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Sample records for ballistic impact experiments

  1. Buildings vs. ballistics: Quantifying the vulnerability of buildings to volcanic ballistic impacts using field studies and pneumatic cannon experiments

    Science.gov (United States)

    Williams, G. T.; Kennedy, B. M.; Wilson, T. M.; Fitzgerald, R. H.; Tsunematsu, K.; Teissier, A.

    2017-09-01

    Recent casualties in volcanic eruptions due to trauma from blocks and bombs necessitate more rigorous, ballistic specific risk assessment. Quantitative assessments are limited by a lack of experimental and field data on the vulnerability of buildings to ballistic hazards. An improved, quantitative understanding of building vulnerability to ballistic impacts is required for informing appropriate life safety actions and other risk reduction strategies. We assessed ballistic impacts to buildings from eruptions at Usu Volcano and Mt. Ontake in Japan and compiled available impact data from eruptions elsewhere to identify common damage patterns from ballistic impacts to buildings. We additionally completed a series of cannon experiments which simulate ballistic block impacts to building claddings to investigate their performance over a range of ballistic projectile velocities, masses and energies. Our experiments provide new insights by quantifying (1) the hazard associated with post-impact shrapnel from building and rock fragments; (2) the effect of impact obliquity on damage; and (3) the additional impact resistance buildings possess when claddings are struck in areas directly supported by framing components. This was not well identified in previous work which may have underestimated building vulnerability to ballistic hazards. To improve assessment of building vulnerability to ballistics, we use our experimental and field data to develop quantitative vulnerability models known as fragility functions. Our fragility functions and field studies show that although unreinforced buildings are highly vulnerable to large ballistics (> 20 cm diameter), they can still provide shelter, preventing death during eruptions.

  2. Modeling and experiments on ballistic impact into UHMWPE yarns using flat and saddle-nosed projectiles

    NARCIS (Netherlands)

    Phoenix, S.L.; Heisserer, U.; Werff, H. van der; Jagt-Deutekom , M.J. van der

    2017-01-01

    Yarn shooting experiments were conducted to determine the ballistically-relevant, Young’s modulus and tensile strength of ultra-high molecular weight polyethylene (UHMWPE) fiber. Target specimens were Dyneema® SK76 yarns (1760 dtex), twisted to 40 turns/m, and initially tensioned to stresses ranging

  3. Impacts of Deflection Nose on Ballistic Trajectory Control Law

    Directory of Open Access Journals (Sweden)

    Bo Zhang

    2014-01-01

    Full Text Available The deflection of projectile nose is aimed at changing the motion of the projectile in flight with the theory of motion control and changing the exterior ballistics so as to change its range and increase its accuracy. The law of external ballistics with the deflectable nose is considered as the basis of the design of a flight control system and an important part in the process of projectile development. Based on the existing rigid external ballistic model, this paper establishes an external ballistic calculation model for deflectable nose projectile and further establishes the solving programs accordingly. Different angle of attack, velocity, coefficients of lift, resistance, and moment under the deflection can be obtained in this paper based on the previous experiments and emulation researches. In the end, the author pointed out the laws on the impaction of external ballistic trajectory by the deflection of nose of the missile.

  4. Numerical Simulation of Ballistic Impact of Layered Aluminum Nitride Ceramic

    Science.gov (United States)

    2015-09-01

    ARL-TR-7416 ● SEP 2015 US Army Research Laboratory Numerical Simulation of Ballistic Impact of Layered Aluminum Nitride Ceramic...of Ballistic Impact of Layered Aluminum Nitride Ceramic by JD Clayton Weapons and Materials Research Directorate, ARL...Numerical Simulation of Ballistic Impact of Layered Aluminum Nitride Ceramic 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

  5. Towards reliable simulations of ballistic impact on concrete structures

    NARCIS (Netherlands)

    Khoe, Y.S.; Tyler Street, M.D.; Maravalalu Suresh,, R.S.; Weerheijm, J.

    2013-01-01

    Protection against weapon effects like ballistic impacts, fragmenting shells and explosions is the core business of the Explosions, Ballistics and Protection department of TNO (The Netherlands). Experimental and numerical research is performed to gain and maintain the knowledge to support the Dutch

  6. Ballistic Impact Simulation of Ceramic/Metal Armor Structures

    OpenAIRE

    ARSLAN, Kemal; GÜNEŞ, Recep

    2017-01-01

    The study presents a comparative numericalinvestigation on ballistic performance of ceramic/metal armor structures. 2Daxisymmetric numerical model was developed for ballistic impact simulationsusing LS-DYNA® finite element software. The armor structuresincluded combinations of boron carbide (B4C), Al6061-T6 and 4340steel constituents. The interfaces in the armor structure were modelled with anepoxy resin adhesive. In order to define proper material behavior,Johnson-Holmquist-Ceramics material...

  7. Comparison of ballistic impact effects between biological tissue and gelatin.

    Science.gov (United States)

    Jin, Yongxi; Mai, Ruimin; Wu, Cheng; Han, Ruiguo; Li, Bingcang

    2018-02-01

    Gelatin is commonly used in ballistic testing as substitute for biological tissue. Comparison of ballistic impact effects produced in the gelatin and living tissue is lacking. The work in this paper was aimed to compare the typical ballistic impact effects (penetration trajectory, energy transfer, temporary cavity) caused by 4.8mm steel ball penetrating the 60kg porcine hind limbs and 10wt% gelatin. The impact event in the biological tissue was recorded by high speed flash X-ray machine at different delay time, while the event in the gelatin continuously recorded by high speed video was compared to that in the biological tissue. The collected results clearly displayed that the ballistic impact effects in the muscle and gelatin were similar for the steel ball test; as for instance, the projectile trajectory in the two targets was basically similar, the process of energy transfer was highly coincident, and the expansion of temporary cavity followed the same pattern. This study fully demonstrated that choosing gelatin as muscle simulant was reasonable. However, the maximum temporary cavity diameter in the gelatin was a little larger than that in the muscle, and the expansion period of temporary cavity was longer in the gelatin. Additionally, the temporary cavity collapse process in the two targets followed different patterns, and the collapse period in the gelatin was two times as long as that in the muscle. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Ballistic Behaviour of Thick Steel Armour Plate under Oblique Impact: Experimental Investigation .

    OpenAIRE

    S. N. Dikshit

    1998-01-01

    The ballistic behaviour of thick steel amlOW- plate has been investigated at different obliquity when impacted by an ogive-shaped steel projectile. The ballistic experiments have been conducted in the velocity range 300-800 m/s. Both the thickness of the target plate and the diameter of the projectile were 20 Inm. At 30 and 45. obliquity 20 mm plate provides full protection at 800 m/s, whereas at 0 and 15. obliquity, the plate provides protection up to 600 m/s. At 15 and 30° obliquity, the pl...

  9. Ballistic Behaviour of Thick Steel Armour Plate under Oblique Impact : Experimental Investigation II

    OpenAIRE

    S. N. Dikshit

    1999-01-01

    The ballistic behaviour of thick steel armour plate at different obliquities has been investigated. Ballistic experiments were conducted in the velocity range 300-800 mls at 0°, 15°, 30° and 45° obliquity .A steel, conical projectile or 6.1 mm diameter was impacted on a 10 mm thick steel armour plate. At 30° and 45° obliquity, the plate offers protection up to a striking velocity of 800 mls. At zero obliquity, the plate provides protection below 6~ m/s. The depth of penetration decreases with...

  10. High Resolution, High-Speed Photography, an Increasingly Prominent Diagnostic in Ballistic Research Experiments

    International Nuclear Information System (INIS)

    Shaw, L.; Muelder, S.

    1999-01-01

    High resolution, high-speed photography is becoming a prominent diagnostic in ballistic experimentation. The development of high speed cameras utilizing electro-optics and the use of lasers for illumination now provide the capability to routinely obtain high quality photographic records of ballistic style experiments. The purpose of this presentation is to review in a visual manner the progress of this technology and how it has impacted ballistic experimentation. Within the framework of development at LLNL, we look at the recent history of large format high-speed photography, and present a number of photographic records that represent the state of the art at the time they were made. These records are primarily from experiments involving shaped charges. We also present some examples of current photographic technology, developed within the ballistic community, that has application to hydro diagnostic experimentation at large. This paper is designed primarily as an oral-visual presentation. This written portion is to provide general background, a few examples, and a bibliography

  11. Ballistic impact resistance of selected organic ophthalmic lenses.

    Science.gov (United States)

    Chou, B Ralph; Yuen, Gloria S-C; Dain, Stephen J

    2011-11-01

    The aim was to assess the impact resistance of coated and uncoated mid-index spectacle lens materials using the ballistic impact test. Nominally plano lenses of each material in three thicknesses were obtained. The lenses were flat edged to a 50 mm diameter. Each lens was impacted by a 6.35 mm steel ball. Impact velocities were selected using the Zippy Estimation by Sequential Testing protocol to determine the threshold fracture impact velocity. Threshold fracture impact velocity generally increased with thickness; however, there was a wide variation in performance among the various lens materials at each thickness. In all but two instances, the differences in impact velocity at each thickness of lens material were significant. Comparison of the data for CR39 and Hoya Phoenix with the results of earlier studies showed that the lens mounting is a significant factor. The fracture velocities found in the present study were significantly lower than the fracture velocities found when the lens edge is restrained in the mounting. A scratch resistant coating reduced the impact resistance of CR39. The effect of the antireflection coating on the fracture velocity depended on the nature of the base scratch-resistant coating. Mid-index lens materials of the same thickness show widely varying levels of impact resistance under the ballistic test. Impact resistance increases non-linearly with centre thickness. The lens mounting might affect the results of the ballistic impact test. The presence of 'cushion coatings' might enhance impact resistance. © 2011 The Authors. Clinical and Experimental Optometry © 2011 Optometrists Association Australia.

  12. Hybrid Composite Laminates Reinforced with Kevlar/Carbon/Glass Woven Fabrics for Ballistic Impact Testing

    Directory of Open Access Journals (Sweden)

    Elias Randjbaran

    2014-01-01

    Full Text Available Current study reported a facile method to investigate the effects of stacking sequence layers of hybrid composite materials on ballistic energy absorption by running the ballistic test at the high velocity ballistic impact conditions. The velocity and absorbed energy were accordingly calculated as well. The specimens were fabricated from Kevlar, carbon, and glass woven fabrics and resin and were experimentally investigated under impact conditions. All the specimens possessed equal mass, shape, and density; nevertheless, the layers were ordered in different stacking sequence. After running the ballistic test at the same conditions, the final velocities of the cylindrical AISI 4340 Steel pellet showed how much energy was absorbed by the samples. The energy absorption of each sample through the ballistic impact was calculated; accordingly, the proper ballistic impact resistance materials could be found by conducting the test. This paper can be further studied in order to characterise the material properties for the different layers.

  13. Hybrid composite laminates reinforced with Kevlar/carbon/glass woven fabrics for ballistic impact testing.

    Science.gov (United States)

    Randjbaran, Elias; Zahari, Rizal; Jalil, Nawal Aswan Abdul; Majid, Dayang Laila Abang Abdul

    2014-01-01

    Current study reported a facile method to investigate the effects of stacking sequence layers of hybrid composite materials on ballistic energy absorption by running the ballistic test at the high velocity ballistic impact conditions. The velocity and absorbed energy were accordingly calculated as well. The specimens were fabricated from Kevlar, carbon, and glass woven fabrics and resin and were experimentally investigated under impact conditions. All the specimens possessed equal mass, shape, and density; nevertheless, the layers were ordered in different stacking sequence. After running the ballistic test at the same conditions, the final velocities of the cylindrical AISI 4340 Steel pellet showed how much energy was absorbed by the samples. The energy absorption of each sample through the ballistic impact was calculated; accordingly, the proper ballistic impact resistance materials could be found by conducting the test. This paper can be further studied in order to characterise the material properties for the different layers.

  14. A School Experiment in Kinematics: Shooting from a Ballistic Cart

    Science.gov (United States)

    Kranjc, T.; Razpet, N.

    2011-10-01

    Many physics textbooks start with kinematics. In the lab, students observe the motions, describe and make predictions, and get acquainted with basic kinematics quantities and their meaning. Then they can perform calculations and compare the results with experimental findings. In this paper we describe an experiment that is not often done, but is interesting and attractive to students—the ballistic cart, i.e., the shooting of a ball from a cart moving along a slope. For that, one has to be familiar with one-dimensional uniform motion and one-dimensional motion with constant acceleration, as well as curvilinear motion that is a combination of such motions.1,2 The experimental results confirm theoretical predictions.

  15. Experiments with Liquid Propellant Jet Ignition in a Ballistic Compressor

    National Research Council Canada - National Science Library

    Birk, Avi

    1998-01-01

    .... The apparatus consists of an inline ballistic compressor and LP injector. The rebound of the ballistic compressor piston was arrested, trapping 40 to 55 MPa of 750 to 8500 C argon for ignition of circular jets in a windowed test chamber...

  16. A comparison of the behind armour blunt trauma effects between ceramic faced and soft body armours caused by ballistic impact

    OpenAIRE

    Lewis, E. A.; Horsfall, Ian; Watson, Celia H.

    2002-01-01

    Recently published research has characterised the behind armour blunt trauma (BABT) effects associated with high velocity ballistic impact on textile-based armour faced with a ceramic plate. Subsequently dynamic displacements, accelerations and pressures have been characterised both in Gelatine experiments and animal experiments and used to provide test methodologies. High velocity armour consists of a ceramic plate usually backed with a composite panel, which is worn over the conventional te...

  17. High Speed Thermal Imaging on Ballistic Impact of Triaxially Braided Composites

    Science.gov (United States)

    Johnston, Joel P.; Pereira, J. Michael; Ruggeri, Charles R.; Roberts, Gary D.

    2017-01-01

    Ballistic impact experiments were performed on triaxially braided polymer matrix composites to study the heat generated in the material due to projectile velocity and penetration damage. Quantifying the heat generation phenomenon is crucial for attaining a better understanding of composite behavior and failure under impact loading. The knowledge gained can also be used to improve physics-based models which can numerically simulate impact of composites. Triaxially braided (0/+60/-60) composite panels were manufactured with T700S standard modulus carbon fiber and two epoxy resins. The PR520 (toughened) and 3502 (untoughened) resin systems were used to make different panels to study the effects of resin properties on temperature rise. Ballistic impact tests were conducted on these composite panels using a gas gun, and different projectile velocities were applied to study the effect on the temperature results. Temperature contours were obtained from the rear surface of the panel during the test through a high speed, infrared (IR) thermal imaging system. The contours show that high temperatures were locally generated and more pronounced along the axial tows for the T700S/PR520 composite specimens; whereas, tests performed on T700S/3502 composite panels using similar impact velocities demonstrated a widespread area of lower temperature rises. Nondestructive, ultrasonic C-scan analyses were performed to observe and verify the failure patterns in the impacted panels. Overall, the impact experimentation showed temperatures exceeding 525 K (485degF) in both composites which is well above the respective glass transition temperatures for the polymer constituents. This expresses the need for further high strain rate testing and measurement of the temperature and deformation fields to fully understand the complex behavior and failure of the material in order to improve the confidence in designing aerospace components with these materials.

  18. Wound Ballistics Modeling for Blast Loading Blunt Force Impact and Projectile Penetration

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Paul A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cooper, Candice Frances [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Burnett, Damon J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    Light body armor development for the warfighter is based on trial-and-error testing of prototype designs against ballistic projectiles. Torso armor testing against blast is virtually nonexistent but necessary to ensure adequate protection against injury to the heart and lungs. In this report, we discuss the development of a high-fidelity human torso model, it's merging with the existing Sandia Human Head-Neck Model, and development of the modeling & simulation (M&S) capabilities necessary to simulate wound injury scenarios. Using the new Sandia Human Torso Model, we demonstrate the advantage of virtual simulation in the investigation of wound injury as it relates to the warfighter experience. We present the results of virtual simulations of blast loading and ballistic projectile impact to the tors o with and without notional protective armor. In this manner, we demonstrate the ad vantages of applying a modeling and simulation approach to the investigation of wound injury and relative merit assessments of protective body armor without the need for trial-and-error testing.

  19. Strengthening the composite protective shield of light-weight ship against ballistic impacts: analytical and experimental

    Directory of Open Access Journals (Sweden)

    I. Jalili

    Full Text Available Light and medium protection for small naval vessels guarantees their high performance and safety during the guard duties. In this study, a protective shield fabricated from Dyneema HB25 fibers has been utilized as an add-on layer on the coast guard boat hull. Finite element analyses have been conducted using Chocron's model. Two standards of gun-fire were employed and various thicknesses of the composite layers were examined by ballistic impacts. Afterward, numerical simulations results compared with experiments and revealed a good consistency. Finally, some graphs have been presented to help designers for choosing more convenient shield based on protection and weight characteristics after judgment of vessel requirements.

  20. Ballistic Resistance of Honeycomb Sandwich Panels under In-Plane High-Velocity Impact

    Science.gov (United States)

    Yang, Shu; Wang, Dong; Yang, Li-Jun

    2013-01-01

    The dynamic responses of honeycomb sandwich panels (HSPs) subjected to in-plane projectile impact were studied by means of explicit nonlinear finite element simulations using LS-DYNA. The HSPs consisted of two identical aluminum alloy face-sheets and an aluminum honeycomb core featuring three types of unit cell configurations (regular, rectangular-shaped, and reentrant hexagons). The ballistic resistances of HSPs with the three core configurations were first analyzed. It was found that the HSP with the reentrant auxetic honeycomb core has the best ballistic resistance, due to the negative Poisson's ratio effect of the core. Parametric studies were then carried out to clarify the influences of both macroscopic (face-sheet and core thicknesses, core relative density) and mesoscopic (unit cell angle and size) parameters on the ballistic responses of the auxetic HSPs. Numerical results show that the perforation resistant capabilities of the auxetic HSPs increase as the values of the macroscopic parameters increase. However, the mesoscopic parameters show nonmonotonic effects on the panels' ballistic capacities. The empirical equations for projectile residual velocities were formulated in terms of impact velocity and the structural parameters. It was also found that the blunter projectiles result in higher ballistic limits of the auxetic HSPs. PMID:24187526

  1. Friction Stir Weld Failure Mechanisms in Aluminum-Armor Structures Under Ballistic Impact Loading Conditions

    Science.gov (United States)

    Grujicic, M.; Pandurangan, B.; Arakere, A.; Yen, C.-F.; Cheeseman, B. A.

    2013-01-01

    A critical assessment is carried out of the microstructural changes in respect of the associated reductions in material mechanical properties and of the attendant ballistic-impact failure mechanisms in prototypical friction stir welding (FSW) joints found in armor structures made of high-performance aluminum alloys (including solution-strengthened and age-hardenable aluminum alloy grades). It is argued that due to the large width of FSW joints found in thick aluminum-armor weldments, the overall ballistic performance of the armor is controlled by the ballistic limits of its weld zones (e.g., heat-affected zone, the thermomechanically affected zone, the nugget, etc.). Thus, in order to assess the overall ballistic survivability of an armor weldment, one must predict/identify welding-induced changes in the material microstructure and properties, and the operative failure mechanisms in different regions of the weld. Toward this end, a procedure is proposed in the present study which combines the results of the FSW process modeling, basic physical-metallurgy principles concerning microstructure/property relations, and the fracture mechanics concepts related to the key blast/ballistic-impact failure modes. The utility of this procedure is demonstrated using the case of a solid-solution strengthened and cold-worked aluminum alloy armor FSW-weld test structure.

  2. Determine ISS Soyuz Orbital Module Ballistic Limits for Steel Projectiles Hypervelocity Impact Testing

    Science.gov (United States)

    Lyons, Frankel

    2013-01-01

    A new orbital debris environment model (ORDEM 3.0) defines the density distribution of the debris environment in terms of the fraction of debris that are low-density (plastic), medium-density (aluminum) or high-density (steel) particles. This hypervelocity impact (HVI) program focused on assessing ballistic limits (BLs) for steel projectiles impacting the enhanced Soyuz Orbital Module (OM) micrometeoroid and orbital debris (MMOD) shield configuration. The ballistic limit was defined as the projectile size on the threshold of failure of the OM pressure shell as a function of impact speeds and angle. The enhanced OM shield configuration was first introduced with Soyuz 30S (launched in May 2012) to improve the MMOD protection of Soyuz vehicles docked to the International Space Station (ISS). This test program provides HVI data on U.S. materials similar in composition and density to the Russian materials for the enhanced Soyuz OM shield configuration of the vehicle. Data from this test program was used to update ballistic limit equations used in Soyuz OM penetration risk assessments. The objective of this hypervelocity impact test program was to determine the ballistic limit particle size for 440C stainless steel spherical projectiles on the Soyuz OM shielding at several impact conditions (velocity and angle combinations). This test report was prepared by NASA-JSC/ HVIT, upon completion of tests.

  3. Dynamic Load Measurement of Ballistic Gelatin Impact Using an Instrumented Tube

    Science.gov (United States)

    Seidt, J. D.; Periira, J. M.; Hammer, J. T.; Gilat, A.; Ruggeri, C. R.

    2012-01-01

    Bird strikes are a common problem for the aerospace industry and can cause serious damage to an aircraft. Ballistic gelatin is frequently used as a surrogate for actual bird carcasses in bird strike tests. Numerical simulations of these tests are used to supplement experimental data, therefore it is necessary to use numerical modeling techniques that can accurately capture the dynamic response of ballistic gelatin. An experimental technique is introduced to validate these modeling techniques. A ballistic gelatin projectile is fired into a strike plate attached to a 36 in. long sensor tube. Dynamic load is measured at two locations relative to the strike plate using strain gages configured in a full Wheatstone bridge. Data from these experiments are used to validate a gelatin constitutive model. Simulations of the apparatus are analyzed to investigate its performance.

  4. Assessment of Three Finite Element Approaches for Modeling the Ballistic Impact Failure of Metal Plates

    Science.gov (United States)

    Mansur, Ali; Nganbe, Michel

    2015-03-01

    The ballistic impact was numerically modeled for AISI 450 steel struck by a 17.3 g ogive nose WC-Co projectile using Abaqus/Explicit. The model was validated using experimental results and data for different projectiles and metal targets. The Abaqus ductile-shear, local principal strain to fracture, and absorbed strain energy at failure criteria were investigated. Due to the highly dynamic nature of ballistic impacts, the absorbed strain energy approach posed serious challenges in estimating the effective deformation volume and yielded the largest critical plate thicknesses for through-thickness penetration (failure). In contrast, the principal strain criterion yielded the lowest critical thicknesses and provided the best agreement with experimental ballistic test data with errors between 0 and 30%. This better accuracy was due to early failure definition when the very first mesh at the target back side reached the strain to fracture, which compensated for the overall model overestimation. The ductile-shear criterion yielded intermediate results between those of the two comparative approaches. In contrast to the ductile-shear criterion, the principal strain criterion requires only basic data readily available for practically all materials. Therefore, it is a viable alternative for an initial assessment of the ballistic performance and pre-screening of a large number of new candidate materials as well as for supporting the development of novel armor systems.

  5. Phase Contrast Imaging of Damage Initiation During Ballistic Impact of Boron Carbide

    Science.gov (United States)

    Schuster, Brian; Tonge, Andrew; Ramos, Kyle; Rigg, Paulo; Iverson, Adam; Schuman, Adam; Lorenzo, Nicholas

    2017-06-01

    For several decades, flash X-ray imaging has been used to perform time-resolved investigations of the response of ceramics under ballistic impact. Traditional absorption based contrast offers little insight into the early initiation of inelastic deformation mechanisms and instead typically only shows the gross deformation and fracture behavior. In the present work, we employed phase contrast imaging (PCI) at the Dynamic Compression Sector (DCS) at the Advanced Photon Source, Argonne National Laboratory, to investigate crack initiation and propagation following the impact of copper penetrators into boron carbide targets. These experiments employed a single-stage propellant gun to launch small-scale (0.6 mm diameter by 3 mm long) pure copper impactors at velocities ranging from 0.9 to 1.9 km/s into commercially available boron carbide targets that were 8 mm on a side. At the lowest striking velocities the penetrator undergoes dwell or interface defeat and the target response is consistent with the cone crack formation at the impact site. At higher striking velocities there is a distinct transition to massive fragmentation leading to the onset of penetration.

  6. Experiments and modeling of ballistic penetration using an energy failure criterion

    Directory of Open Access Journals (Sweden)

    Dolinski M.

    2015-01-01

    Full Text Available One of the most intricate problems in terminal ballistics is the physics underlying penetration and perforation. Several penetration modes are well identified, such as petalling, plugging, spall failure and fragmentation (Sedgwick, 1968. In most cases, the final target failure will combine those modes. Some of the failure modes can be due to brittle material behavior, but penetration of ductile targets by blunt projectiles, involving plugging in particular, is caused by excessive localized plasticity, with emphasis on adiabatic shear banding (ASB. Among the theories regarding the onset of ASB, new evidence was recently brought by Rittel et al. (2006, according to whom shear bands initiate as a result of dynamic recrystallization (DRX, a local softening mechanism driven by the stored energy of cold work. As such, ASB formation results from microstructural transformations, rather than from thermal softening. In our previous work (Dolinski et al., 2010, a failure criterion based on plastic strain energy density was presented and applied to model four different classical examples of dynamic failure involving ASB formation. According to this criterion, a material point starts to fail when the total plastic strain energy density reaches a critical value. Thereafter, the strength of the element decreases gradually to zero to mimic the actual material mechanical behavior. The goal of this paper is to present a new combined experimental-numerical study of ballistic penetration and perforation, using the above-mentioned failure criterion. Careful experiments are carried out using a single combination of AISI 4340 FSP projectiles and 25[mm] thick RHA steel plates, while the impact velocity, and hence the imparted damage, are systematically varied. We show that our failure model, which includes only one adjustable parameter in this present work, can faithfully reproduce each of the experiments without any further adjustment. Moreover, it is shown that the

  7. A ballistic transport model for electronic excitation following particle impact

    Science.gov (United States)

    Hanke, S.; Heuser, C.; Weidtmann, B.; Wucher, A.

    2018-01-01

    We present a ballistic model for the transport of electronic excitation energy induced by keV particle bombardment onto a solid surface. Starting from a free electron gas model, the Boltzmann transport equation (BTE) is employed to follow the evolution of the temporal and spatial distribution function f (r → , k → , t) describing the occupation probability of an electronic state k → at position r → and time t. Three different initializations of the distribution function are considered: i) a thermal distribution function with a locally and temporally elevated electron temperature, ii) a peak excitation at a specific energy above the Fermi level with a quasi-isotropic distribution in k-space and iii) an anisotropic peak excitation with k-vectors oriented in a specific transport direction. While the first initialization resembles a distribution function which may, for instance, result from electronic friction of moving atoms within an ion induced collision cascade, the peak excitation can in principle result from an autoionization process after excitation in close binary collisions. By numerically solving the BTE, we study the electronic energy exchange along a one dimensional transport direction to obtain a time and space resolved excitation energy distribution function, which is then analyzed in view of general transport characteristics of the chosen model system.

  8. KevlarTM Fiber-Reinforced Polybenzoxazine Alloys for Ballistic Impact Application

    Directory of Open Access Journals (Sweden)

    Chanchira Jubsilp

    2011-10-01

    Full Text Available A light weight ballistic composites from KevlarTM-reinforcing fiber having polybenzoxazine (BA/urethane prepolymer (PU alloys as a matrix were investigated in this work. The effect of alloy compositions on the ballistic composite properties was determined. The results revealed that the enhancement in the glass transition temperature (Tg of the KevlarTM-reinforced BA/PU composites compared to that of the KevlarTM-reinforced polybenzoxazine composite was observed. The increase of the elastomeric PU content in the BA/PU alloy resulted in samples with tougher characteristics. The storage modulus of the KevlarTM-reinforced BA/PU composites increased with increasing the mass fraction of polybenzoxazine. A ballistic impact test was also performed on the KevlarTM-reinforced BA/PU composites using a 9 mm handgun. It was found that the optimal contents of PU in the BA/PU alloys should be approximately 20wt%. The extent of the delaminated area and interfacial fracture were observed to change with the varied compositions of the matrix alloys. The appropriate thickness of KevlarTM-reinforced 80/20 BA/PU composite panel was 30 plies and 50 plies to resist the penetration from the ballistic impact equivalent to levels II-A and III-A of NIJ standard. The arrangement of composite panels with the higher stiffness panel at the front side also showed the best efficiency of ballistic penetration resistance.

  9. On the influence of particle morphology on the post-impact ballistic response of ceramic armour materials

    Science.gov (United States)

    Hameed, Amer; Appleby-Thomas, Gareth; Wood, David; Jaansalu, Kevin

    2015-06-01

    Recent studies have shown evidence that the ballistic-resistance of fragmented (comminuted) ceramics is independent of the original strength of the material. In particular, experimental investigations into the ballistic behaviour of such fragmented ceramics have indicated that this response is correlated to shattered ceramic morphology. This suggests that careful control of ceramic microstructure - and therefore failure paths - might provide a route to optimise post-impact ballistic performance, thereby enhancing multi-hit capability. In this study, building on previous in-house work, ballistic tests were conducted using pre-formed `fragmented-ceramic' analogues based around three morphologically differing (but chemically identical) alumina feedstock materials compacted into target `pucks. In an evolution of previous work, variation of target thickness provided additional insight into an apparent morphology-based contribution to ballistic response.

  10. Penetration of sandwich plates with hybrid-cores under oblique ballistic impact

    Directory of Open Access Journals (Sweden)

    Changye Ni

    2014-01-01

    Full Text Available The oblique penetration performance of lightweight hybrid-cored sandwich plates are investigated numerically. To compose the hybrid-core, ceramic prisms are inserted into pyramidal metal lattice trusses and fixed using epoxy resin. Three-dimensional finite element simulations are carried out for the hybridcored sandwich impacted at 15°, 30°, 45°, and 60° obliquity by a hemispherical projectile. The ballistic limit, the energy absorbed by the constituting elements, and the critical oblique angle are quantified. The physical mechanisms underlying the failure and the influence of fundamental system parameters are explored. The angle of obliquity is found to have significant influence on the ballistic trajectory and erosion of the projectile, thus it is important for the impact response and penetration resistance of the sandwich. For oblique angles equal to or larger than 45°, the projectile moves mainly horizontally and can not effectively penetrate across the sandwich.

  11. Recent high-speed ballistics experiments at ORNL

    International Nuclear Information System (INIS)

    Combs, S.K.; Gouge, M.J.; Baylor, L.R.; Fisher, P.W.; Foster, C.A.; Foust, C.R.; Milora, S.L.; Qualls, A.L.

    1994-01-01

    Oak Ridge National Laboratory (ORNL) has been developing pellet injectors for plasma fueling experiments on magnetic confinement devices for almost 20 years. With these devices, pellets (1 to 8 mm in diameter) composed of hydrogen isotopes are formed (at temperatures <20 K) and typically accelerated to speeds of ∼ 1.0 to 2.0 km/s for injection into plasmas of experimental fusion devices. A variety of pellet injector designs have been developed at ORNL, including repeating pneumatic injectors (single- and multiple-barrel light gas guns) that can inject up to hundreds of pellets for long-pulse plasma operation. The repeating pneumatic injectors are of particular importance because long-pulse fueling is required for present large experimental fusion devices, with steady-state operation the objective for future fusion reactors. In this paper, recent advancements in the development of repeating pneumatic injectors are described, including (1) a small-bore (1.8-mm), high-firing-rate (10-Hz) version of a single-stage light gas gun; (2) a repeating single-stage light gas gun for 8-mm-diam tritium pellets; (3) a repeating two-stage light gas gun for operation at higher pellet velocities; and (4) a steady-state hydrogen extruder feed system

  12. Combined Structural and Compositional Evolution of Planetary Rings Due to Micrometeoroid Impacts and Ballistic Transport

    Science.gov (United States)

    Estrada, Paul R.; Durisen, Richard H.; Cuzzi, Jeffrey N.; Morgan, Demitri A.

    2015-01-01

    We introduce improved numerical techniques for simulating the structural and compositional evolution of planetary rings due to micrometeoroid bombardment and subsequent ballistic transport of impact ejecta. Our current, robust code is capable of modeling structural changes and pollution transport simultaneously over long times on both local and global scales. In this paper, we describe the methodology based on the original structural code of Durisen et al. (1989, Icarus 80, 136-166) and on the pollution transport code of Cuzzi and Estrada (1998, Icarus 132, 1-35). We provide demonstrative simulations to compare with, and extend upon previous work, as well as examples of how ballistic transport can maintain the observed structure in Saturn's rings using available Cassini occultation optical depth data. In particular, we explicitly verify the claim that the inner B (and presumably A) ring edge can be maintained over long periods of time due to an ejecta distribution that is heavily biased in the prograde direction through a balance between the sharpening effects of ballistic transport and the broadening effects of viscosity. We also see that a "ramp"-like feature forms over time just inside that edge. However, it does not remain linear for the duration of the runs presented here unless a less steep ejecta velocity distribution is adopted. We also model the C ring plateaus and find that their outer edges can be maintained at their observed sharpness for long periods due to ballistic transport. We hypothesize that the addition of a significant component of a retrograde-biased ejecta distribution may help explain the linearity of the ramp and is probably essential for maintaining the sharpness of C ring plateau inner edges. This component would arise for the subset of micrometeoroid impacts which are destructive rather than merely cratering. Such a distribution will be introduced in future work.

  13. Gun Testing Ballistics Issues for Insensitive Munitions Fragment Impact Testing

    Science.gov (United States)

    Baker, Ernest; Schultz, Emmanuel; NATO Munitions Safety Information Analysis Centre Team

    2017-06-01

    The STANAG 4496 Ed. 1 Fragment Impact, Munitions Test Procedure is normally conducted by gun launching a projectile for attack against a munition. The purpose of this test is to assess the reaction of a munition impacted by a fragment. The test specifies a standardized projectile (fragment) with a standard test velocity of 2530+/-90 m/s, or an alternate test velocity of 1830+/-60 m/s. The standard test velocity can be challenging to achieve and has several loosely defined and undefined characteristics that can affect the test item response. This publication documents the results of an international review of the STANAG 4496 related to the fragment impact test. To perform the review, MSIAC created a questionnaire in conjunction with the custodian of this STANAG and sent it to test centers. Fragment velocity variation, projectile tilt upon impact and aim point variation were identified as observed gun testing issues. Achieving 2530 m/s consistently and cost effectively can be challenging. The aim point of impact of the fragment is chosen with the objective of obtaining the most violent reaction. No tolerance for aim point is specified, although aim point variation can be a source for IM response variation. Fragment tilt on impact is also unspecified. The standard fragment fabricated from a variety of different steels which have a significant margin for mechanical properties. These, as well as other gun testing issues, have significant implications to resulting IM response.

  14. Simulation of depth of penetration during ballistic impact on thick ...

    Indian Academy of Sciences (India)

    of predicting residual velocity of projectile, contact time and force time histories. But this model is applicable only for thin metal targets where the projectile will come out from the non-impact end of the target after penetration process. Anderson et al (1993) used energy balance principle and used numerical simulations to ...

  15. Wound Ballistics Modeling for Blast Loading Blunt Force Impact and Projectile Penetration.

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Paul A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-11-01

    Light body armor development for the warfighter is based on trial-and-error testing of prototype designs against ballistic projectiles. Torso armor testing against blast is nonexistent but necessary to protect the heart and lungs. In tests against ballistic projectiles, protective apparel is placed over ballistic clay and the projectiles are fired into the armor/clay target. The clay represents the human torso and its behind-armor, permanent deflection is the principal metric used to assess armor protection. Although this approach provides relative merit assessment of protection, it does not examine the behind-armor blunt trauma to crucial torso organs. We propose a modeling and simulation (M&S) capability for wound injury scenarios to the head, neck, and torso of the warfighter. We will use this toolset to investigate the consequences of, and mitigation against, blast exposure, blunt force impact, and ballistic projectile penetration leading to damage of critical organs comprising the central nervous, cardiovascular, and respiratory systems. We will leverage Sandia codes and our M&S expertise on traumatic brain injury to develop virtual anatomical models of the head, neck, and torso and the simulation methodology to capture the physics of wound mechanics. Specifically, we will investigate virtual wound injuries to the head, neck, and torso without and with protective armor to demonstrate the advantages of performing injury simulations for the development of body armor. The proposed toolset constitutes a significant advance over current methods by providing a virtual simulation capability to investigate wound injury and optimize armor design without the need for extensive field testing.

  16. Deformations on Hole and Projectile Surfaces Caused By High Velocity Friction During Ballistic Impact

    Science.gov (United States)

    Karamış, M. B.

    2018-01-01

    In this study, the deformations caused by the ballistic impact on the MM composites and on projectile surfaces are examined. The hole section and grain deformation of unreinforced targets are also examined after impact. The relatively high complexity of impact problems is caused by the large number of intervening parameters like relative velocity of projectile and target, shape of colliding objects, relative stiffness and masses, time-dependent surface of contact, geometry and boundary conditions and material characteristics. The material used in this investigation are 2024 and 7075 aluminum alloys as matrix reinforced with SiC and Al2O3 particles. The matrix materials are extensively used in defense applications due to its favorable ballistic properties, moderate strength, high corrosion resistance and super plastic potential. Two different composites were produced; one by casting and the other by lamination. The ballistic tests of the composite targets were carried out according to NIJ Standard-0101.04, Temperature 21 °C, RH=65% with 7.62 mm projectiles. The bullet weight was 9.6 g and their muzzle velocities were in the range of 770–800 m/s. The projectiles consisted of a steel core, copper jacket and lead material. The composite targets were positioned 15 m from the rifle. The interaction between projectiles and the target hole created after impact were examined by light microscopy and photography. Different damage and failure mechanisms such as petalling, cracking, spalling, dishing, etc., were observed on the target body. On the other hand, dramatic wear and damages on the projectile surface were also observed. The targets were supported with Al-5083 backing blocks having 40 mm thickness.

  17. Ballistic Impact Response of Woven Hybrid Coir/Kevlar Laminated Composites

    Directory of Open Access Journals (Sweden)

    Azrin Hani A.R

    2016-01-01

    Full Text Available The effects of different laminated hybrid composites stacking configuration subjected to ballistic impact were investigated. The hybrid composites consist of woven coir (C and woven Kevlar (K layers laminated together. The samples of woven coir were prepared using handloom device. The composites were produced by stacking the laminated woven coir and Kevlar alternately with the presence of the binder. The samples were tested under ballistic impact with different stacking configuration. The results obtained had successfully achieved the National Institute of Justice (NIJ standard level IIA with energy absorption of 435.6 kJ and 412.2 kJ under the projectile speed of between 330 m/s and 321 m/s respectively. Samples that having Kevlar layer at the front face and woven coir layer as back face achieved partial penetration during projectile impact. This orientation is proven to have good impact energy absorption and able to stop projectile at the second panel of the composites.

  18. Metallographic characterisation of Al6061-T6 aluminium plates subjected to ballistic impact

    Energy Technology Data Exchange (ETDEWEB)

    Manes, A., E-mail: andrea.manes@polimi.it; Pagani, M.; Saponara, M.; Mombelli, D.; Mapelli, C.; Giglio, M.

    2014-07-01

    Al6061-T6 aluminium single layer plates, of different thickness, impacted by two different 7.62 mm Armour Piercing projectiles are studied from a metallographic point of view. The material behaviour after ballistic impact is investigated by optical and scanning electron microscopy as well as by micro-hardness tests. The study allows one to highlight the physical phenomena that happen during the impact: the formation of adiabatic shear bands (ASB), the evolution of softening and hardening phenomena, the creation of petalling, plugging and the formation of a melted film between the target and the penetrator as well as the localised failure mechanism. The thermo-mechanical effects on the target and the penetrator material have been examined in order to investigate in the physical phenomena ruling the ballistic damage; the differences between the two types of impactors are also highlighted. Among interesting findings, it has been noticed that a complete penetration is less detrimental and tungsten core projectile seems more damaging for the structural integrity of Al6061-T6 plates. A complete penetration allows the material to better dissipate the plastic deformation energy induced by bullet whereas the arrest increases localised material softening effect resulting in the formation of ASB. Although the creation of numerical models is not the aim of the present paper, the findings could be useful for the building of a modelling approach capable of replicating all the involved phenomena in details.

  19. Ballistic Impact Testing of Aluminum 2024 and Titanium 6Al-4V for Material Model Development

    Science.gov (United States)

    Pereira, J. Michael; Revilock, Duane M.; Ruggeri, Charles R.; Emmerling, William C.; Altobelli, Donald J.

    2012-01-01

    An experimental program is underway to develop a consistent set of material property and impact test data, and failure analysis, for a variety of materials that can be used to develop improved impact failure and deformation models. Unique features of this set of data are that all material property information and impact test results are obtained using identical materials, the test methods and procedures are extensively documented and all of the raw data is available. This report describes ballistic impact testing which has been conducted on aluminum (Al) 2024 and titanium (Ti) 6Al-4vanadium (V) sheet and plate samples of different thicknesses and with different types of projectiles, one a regular cylinder and one with a more complex geometry incorporating features representative of a jet engine fan blade.

  20. Ballistic impacts on an anatomically correct synthetic skull with a surrogate skin/soft tissue layer.

    Science.gov (United States)

    Mahoney, Peter; Carr, Debra; Arm, Richard; Gibb, Iain; Hunt, Nicholas; Delaney, Russ J

    2018-03-01

    The aim of this work was to further develop a synthetic model of ballistic head injury by the addition of skin and soft tissue layers to an anatomically correct polyurethane skull filled with gelatine 10% by mass. Six head models were impacted with 7.62 x 39 mm full metal jacket mild steel core (FMJ MSC) bullets with a mean velocity of 652 m/s. The impact events were filmed with high-speed cameras. The models were imaged pre- and post-impact using computed tomography. The models were assessed post impact by two experienced Home Office pathologists and the images assessed by an experienced military radiologist. The findings were scored against real injuries. The entry wounds, exit wounds and fracture patterns were scored positively, but the synthetic skin and soft tissue layer was felt to be too extendable. Further work is ongoing to address this.

  1. Vibration and Energy Dissipation of Nanocomposite Laminates for Below Ballistic Impact Loading

    Directory of Open Access Journals (Sweden)

    G. Balaganesan

    Full Text Available Abstract Composite laminates are made of glass woven roving mats of 610gsm, epoxy resin and nano clay which are subjected to projectile impact. Nano clay dispersion is varied from 1% to 5%. Impact tests are conducted in a gas gun setup with a spherical nose cylindrical projectile of diameter 9.5 mm of mass 7.6 g. The energy absorbed by the laminates when subjected to impact loading is studied, the velocity range is below ballistic limit. The effect of nano clay on energy absorption in vibration, delamination and matrix crack is studied for different weight % of nano clay and for different thickness values of the laminates. The natural frequencies and damping factors are obtained for the laminates during impact and the effect of nano clay is studied. The results show considerable improvement in energy absorption due to the presence of nano clay

  2. Hybrid Carbon-Glass Fiber/Toughened Epoxy Thick Composite Joints Subject to Drop-Weight and Ballistic Impacts

    National Research Council Canada - National Science Library

    Liaw, Benjamin; Delale, Feridun

    2007-01-01

    .... The main objectives of this project are (1) to conduct tensile, drop-weight impact and ballistic impact tests of monolithic S2 glass fiber/toughened epoxy composites and hybrid carbon-S2 glass fiber/toughened epoxy composites, (2...

  3. One Dimension Analytical Model of Normal Ballistic Impact on Ceramic/Metal Gradient Armor

    International Nuclear Information System (INIS)

    Liu Lisheng; Zhang Qingjie; Zhai Pengcheng; Cao Dongfeng

    2008-01-01

    An analytical model of normal ballistic impact on the ceramic/metal gradient armor, which is based on modified Alekseevskii-Tate equations, has been developed. The process of gradient armour impacted by the long rod can be divided into four stages in this model. First stage is projectile's mass erosion or flowing phase, mushrooming phase and rigid phase; second one is the formation of comminuted ceramic conoid; third one is the penetration of gradient layer and last one is the penetration of metal back-up plate. The equations of third stage have been advanced by assuming the behavior of gradient layer as rigid-plastic and considering the effect of strain rate on the dynamic yield strength

  4. Ballistics Trajectory and Impact Analysis for Insensitive Munitions and Hazard Classification Project Criteria

    Science.gov (United States)

    Baker, Ernest; van der Voort, Martijn; NATO Munitions Safety Information Analysis Centre Team

    2017-06-01

    Ballistics trajectory and impact conditions calculations were conducted in order to investigate the origin of the projection criteria for Insensitive Munitions (IM) and Hazard Classification (HC). The results show that the existing IM and HC projection criteria distance-mass relations are based on launch energy rather than impact conditions. The distance-mass relations were reproduced using TRAJCAN trajectory analysis by using launch energies of 8, 20 and 79J and calculating the maximum impact distance reached by a natural fragment (steel) launched from 1 m height. The analysis shows that at the maximum throw distances, the impact energy is generally much smaller than the launch energy. Using maximum distance projections, new distance-mass relations were developed that match the criteria based on impact energy at 15m and beyond rather than launch energy. Injury analysis was conducted using penetration injury and blunt injury models. The smallest projectile masses in the distance-mass relations are in the transition region from penetration injury to blunt injury. For this reason, blunt injury dominates the assessment of injury or lethality. State of the art blunt injury models predict only minor injury for a 20J impact. For a 79J blunt impact, major injury is likely to occur. MSIAC recommends changing the distance-mass relation that distinguishes a munitions burning response to a 20 J impact energy criterion at 15 m and updating of the UN Orange Book.

  5. Hybrid Carbon-Glass Fiber/Toughened Epoxy Thick Composite Joints Subject to Drop-Weight and Ballistic Impacts

    National Research Council Canada - National Science Library

    Liaw, Benjamin; Delale, Feridun

    2007-01-01

    ... No. DAAD19-02-R-0010 to conduct research on hybrid carbon-S2 glass fiber/toughened epoxy thick-section, hybrid interwoven composite joints subject to drop-weight and ballistic impacts. Dr. Basavaraju B. Raju of U.S...

  6. Simulation of impact ballistic of Cu-10wt%Sn frangible bullet using smoothed particle hydrodynamics

    Science.gov (United States)

    Hidayat, Mas Irfan P.; Widyastuti, Simaremare, Peniel

    2018-04-01

    Frangible bullet is designed to disintegrate upon impact against a hard target. Understanding the impact response and performance of frangible bullet is therefore of highly interest. In this paper, simulation of impact ballistic of Cu-IOwt%Sn frangible bullet using smoothed particle hydrodynamics (SPH) method is presented. The frangible bullet is impacted against a hard, cylindrical stainless steel target. Effect of variability of the frangible bullet material properties due to the variation of sintering temperature in its manufacturing process to the bullet frangibility factor (FF) is investigated numerically. In addition, the bullet kinetic energy during impact as well as its ricochet and fragmentation are also examined and simulated. Failure criterion based upon maximum strain is employed in the simulation. It is shown that the SPH simulation can produce good estimation for kinetic energy of bullet after impact, thus giving the FF prediction with respect to the variation of frangible bullet material properties. In comparison to explicit finite element (FE) simulation, in which only material/element deletion is shown, convenience in showing frangible bullet fragmentation is shown using the SPH simulation. As a result, the effect of sintering temperature to the way of the frangible bullet fragmented can be also observed clearly.

  7. Terminal ballistics

    CERN Document Server

    Rosenberg, Zvi

    2016-01-01

    This book comprehensively discusses essential aspects of terminal ballistics, combining experimental data, numerical simulations and analytical modeling. Employing a unique approach to numerical simulations as a measure of sensitivity for the major physical parameters, the new edition also includes the following features: new figures to better illustrate the problems discussed; improved explanations for the equation of state of a solid and for the cavity expansion process; new data concerning the Kolsky bar test; and a discussion of analytical modeling for the hole diameter in a thin metallic plate impacted by a shaped charge jet. The section on thick concrete targets penetrated by rigid projectiles has now been expanded to include the latest findings, and two new sections have been added: one on a novel approach to the perforation of thin concrete slabs, and one on testing the failure of thin metallic plates using a hydrodynamic ram.

  8. Effect of Hardness on the Ballistic Impact Behavior of High-Strength Steels Against 7.62-mm Armor Piercing Projectiles

    Science.gov (United States)

    Demir, Teyfik; Übeyli, Mustafa; Yıldırım, R. O.

    2009-03-01

    Ballistic performance of engineering materials should be known in selection of the most suitable armor material to protect civilian or military system with the lowest possible weight against various threats. In this study, the ballistic impact characterization of high-strength steels, namely AISI 4340 and DIN 100Cr6, was investigated using 7.62-mm armor piercing (AP) projectiles by considering four hardness levels and five areal densities. The main aim was to examine the effect of hardness and areal density on the ballistic behavior of these steels. Hence, four different heat-treatment schedules were applied to these steels to get different mechanical properties. After ballistic testing, macro and micro examinations of the specimens were carried out to clarify their failure mechanisms. According to the results, the AISI 4340 steel having a hardness of ~50 HRC showed the best ballistic performance among the investigated materials.

  9. Procedure Developed for Ballistic Impact Testing of Composite Fan Containment Concepts

    Science.gov (United States)

    Pereira, J. Michael; Melis, Matthew E.

    1998-01-01

    The fan-containment system in a jet engine is designed to prevent a fan blade from penetrating the engine case in the event that the blade or a portion of the blade separates from the rotor during operation. Usually, these systems consist of a thick metal case that is strong enough to survive such an impact. Other systems consist of a dry aramid fabric wrapped around a relatively thin metal case. In large turbofan engines, metal-containment systems can weigh well over 300 kg, and there is a strong impetus to reduce their weight. As a result, the NASA Lewis Research Center is involved in an effort to develop polymer matrix composite (PMC) fan-containment systems to reduce the weight and cost while maintaining the high levels of safety associated with current systems. Under a Space Act Agreement with AlliedSignal Aircraft Engines, a new ballistic impact test procedure has been developed to quantitatively evaluate the performance of polymer matrix composite systems.

  10. Ballistic Impact Response of Kevlar 49 and Zylon under Conditions Representing Jet Engine Fan Containment

    Science.gov (United States)

    Pereira, J. Michael; Revilock, Duane M.

    2007-01-01

    A ballistic impact test program was conducted to provide validation data for the development of numerical models of blade out events in fabric containment systems. The impact response of two different fiber materials - Kevlar 49 (E.I. DuPont Nemours and Company) and Zylon AS (Toyobo Co., Ltd.) was studied by firing metal projectiles into dry woven fabric specimens using a gas gun. The shape, mass, orientation and velocity of the projectile were varied and recorded. In most cases the tests were designed such that the projectile would perforate the specimen, allowing measurement of the energy absorbed by the fabric. The results for both Zylon and Kevlar presented here represent a useful set of data for the purposes of establishing and validating numerical models for predicting the response of fabrics under conditions simulating those of a jet engine blade release situation. In addition some useful empirical observations were made regarding the effects of projectile orientation and the relative performance of the different materials.

  11. A Comparison of the Deformation Flow and Failure of Two Tungsten Heavy Alloys in Ballistic Impacts

    National Research Council Canada - National Science Library

    Schuster, Brian E; Peterson, Bryan P; Magness, Lee S

    2006-01-01

    .... Small, but consistent, differences in the ballistic performances of the two lots of penetrators were observed in depth of penetration tests, in thick armor steel targets, and in limit velocity...

  12. Computational Predictions of Rear Surface Velocities for Metal Plates under Ballistic Impact

    Science.gov (United States)

    2015-06-01

    Reinecke WG, editor. Ballistics ’99. Proceedings of the 18th International Symposium on Ballistics; 1999 Nov 15–19; San Antonio, TX. Lancaster (PA...Antonio, TX. Lancaster (PA): Technomic Pub Co. p. 761–768. 6. Robinson AC, Brunner TA, Carroll S, Drake R, Garasi CJ, Gardiner T, Haill T, Heath H...material library . While the primary data in this report does not consider fracture models, the comparisons below do include default settings of the JC

  13. Morphoscopic analysis of experimentally produced bony wounds from low-velocity ballistic impact.

    Science.gov (United States)

    Kieser, Jules A; Tahere, Joy; Agnew, Caitlin; Kieser, David C; Duncan, Warwick; Swain, Michael V; Reeves, Matthew T

    2011-12-01

    Understanding how bone behaves when subjected to ballistic impact is of critical importance for forensic questions, such as the reconstruction of shooting events. Yet the literature addressing microscopic anatomical features of gunshot wounds to different types of bone is sparse. Moreover, a biomechanical framework for describing how the complex architecture of bone affects its failure during such impact is lacking. The aim of this study was to examine the morphological features associated with experimental gunshot wounds in slaughtered pig ribs. We shot the 4th rib of 12 adult pigs with .22 mm subsonic bullets at close range (5 cm) and examined resultant wounds under the light microscope, scanning electron microscope SEM and micro tomograph μCT. In all cases there was a narrow shot channel followed by spall region, with evidence of plastic deformation with burnishing of the surface bone in the former, and brittle fracture around and through individual Haversian systems in the latter. In all but one case, the entrance wounds were characterized by superficially fractured cortical bone in the form of a well-defined collar, while the exit wounds showed delamination of the periosteum. Inorganic residue was evident in all cases, with electron energy dispersive spectroscopy EDS confirming the presence of carbon, phosphate, lead and calcium. This material appeared to be especially concentrated within the fractured bony collar at the entrance. We conclude that gunshot wounds in flat bones may be morphologically divided into a thin burnished zone at the entry site, and a fracture zone at the exit.

  14. Ballistic Impact Behavior of Nacre-Like Laminated Composites Consisting of B4C Tablets and Polyurea Matrix

    Science.gov (United States)

    Grujicic, M.; Snipes, J. S.; Ramaswami, S.

    2016-03-01

    A nacre-like composite armor consisting of B4C tablets and polyurea matrix is modeled, and its ballistic impact behavior and penetration resistance (under a normal and a 15°-oblique impact by a solid right circular cylindrical projectile) were analyzed using a series of transient, nonlinear dynamic, finite-element analyses. Nacre is a biological material constituting the innermost layer of the shells of gastropods and bivalves. It consists of polygonal tablets of aragonite, tessellated to form individual layers and having the adjacent layers as well as the tablets within a layer bonded by a biopolymer. Due to its highly complex hierarchical microstructure, nacre possesses an outstanding combination of mechanical properties, the properties which are far superior to the ones that are predicted using the homogenization techniques such as the rule of mixtures. The results of the transient nonlinear dynamic analysis pertaining to the ballistic impact response and the penetration resistance of the modeled nacre-like armor are compared with their counterparts for the B4C single-block armor having an identical areal density. Furthermore, the effect of various nacre microstructural features (e.g., surface profiling, micron-scale asperities, mineral bridges between the overlapping tablets lying in adjacent layers) on the ballistic penetration resistance of the nacre-like composite armor is investigated in order to identify an optimal nacre-like composite-armor architecture having the largest penetration resistance. The results obtained clearly show that a nacre-like armor possesses a superior penetration resistance relative to its monolithic counterpart, and that the nacre microstructural features considered play a critical role in the armor penetration resistance.

  15. Effect of Mesoscale and Multiscale Modeling on the Performance of Kevlar Woven Fabric Subjected to Ballistic Impact: A Numerical Study

    Science.gov (United States)

    Jia, Xin; Huang, Zhengxiang; Zu, Xudong; Gu, Xiaohui; Xiao, Qiangqiang

    2013-12-01

    In this study, an optimal finite element model of Kevlar woven fabric that is more computational efficient compared with existing models was developed to simulate ballistic impact onto fabric. Kevlar woven fabric was modeled to yarn level architecture by using the hybrid elements analysis (HEA), which uses solid elements in modeling the yarns at the impact region and uses shell elements in modeling the yarns away from the impact region. Three HEA configurations were constructed, in which the solid element region was set as about one, two, and three times that of the projectile's diameter with impact velocities of 30 m/s (non-perforation case) and 200 m/s (perforation case) to determine the optimal ratio between the solid element region and the shell element region. To further reduce computational time and to maintain the necessary accuracy, three multiscale models were presented also. These multiscale models combine the local region with the yarn level architecture by using the HEA approach and the global region with homogenous level architecture. The effect of the varying ratios of the local and global area on the ballistic performance of fabric was discussed. The deformation and damage mechanisms of fabric were analyzed and compared among numerical models. Simulation results indicate that the multiscale model based on HEA accurately reproduces the baseline results and obviously decreases computational time.

  16. Terminal Ballistics

    CERN Document Server

    Rosenberg, Zvi

    2012-01-01

    This book covers the important issues of terminal ballistics in a comprehensive way combining experimental data, numerical simulations and analytical modeling. The first chapter reviews the experimental equipment which are used for ballistic tests and the diagnostics for material characterization under impulsive loading conditions. The second chapter covers essential features of the codes which are used for terminal ballistics such as the Euler vs. Lagrange schemes and meshing techniques, as well as the most popular material models. The third chapter, devoted to the penetration mechanics of rigid penetrators, brings the update of modeling in this field. The fourth chapter deals with plate perforation and the fifth chapter deals with the penetration mechanics of shaped charge jets and eroding long rods. The last two chapters discuss several techniques for the disruption and defeating of the main threats in armor design. Throughout the book the authors demonstrate the advantages of numerical simulations in unde...

  17. Comparison of Ballistic-Coefficient-Based Estimation Algorithms for Precise Tracking of a Re-Entry Vehicle and its Impact Point Prediction

    Directory of Open Access Journals (Sweden)

    Kyung Rok Moon

    2012-12-01

    Full Text Available This paper studies the problem of tracking a re-entry vehicle (RV in order to predict its impact point on the ground. Re-entry target dynamics combined with super-high speed has a complex non-linearity due to ballistic coefficient variations. However, it is difficult to construct a database for the ballistic coefficient of a unknown vehicle for a wide range of variations, thus the reliability of target tracking performance cannot be guaranteed if accurate ballistic coefficient estimation is not achieved. Various techniques for ballistic coefficient estimation have been previously proposed, but limitations exist for the estimation of non-linear parts accurately without obtaining prior information. In this paper we propose the ballistic coefficient β model-based interacting multiple model-extended Kalman filter (β-IMM-EKF for precise tracking of an RV. To evaluate the performance, other ballistic coefficient model based filters, which are gamma augmented filter, gamma bootstrapped filter were compared and assessed with the proposed β-IMM-EKF for precise tracking of an RV.

  18. FAA Development of Reliable Modeling Methodologies for Fan Blade Out Containment Analysis. Part 2; Ballistic Impact Testing

    Science.gov (United States)

    Revilock, Duane M.; Pereira, J. Michael

    2008-01-01

    This report summarizes the ballistic impact testing that was conducted to provide validation data for the development of numerical models of blade out events in fabric containment systems. The ballistic impact response of two different fiber materials - Kevlar 49 (E.I. DuPont Nemours and Company) and Zylon AS (Toyobo Co., Ltd.) was studied by firing metal projectiles into dry woven fabric specimens using a gas gun. The shape, mass, orientation and velocity of the projectile were varied and recorded. In most cases the tests were designed such that the projectile would perforate the specimen, allowing measurement of the energy absorbed by the fabric. The results for both Zylon and Kevlar presented here represent a useful set of data for the purposes of establishing and validating numerical models for predicting the response of fabrics under conditions simulating those of a jet engine blade release situations. In addition some useful empirical observations were made regarding the effects of projectile orientation and the relative performance of the different materials.

  19. Ballistic Limit of High-Strength Steel and Al7075-T6 Multi-Layered Plates Under 7.62-mm Armour Piercing Projectile Impact

    Directory of Open Access Journals (Sweden)

    N. A. Rahman

    Full Text Available Abstract This paper presents the computational-based ballistic limit of laminated metal panels comprised of high strength steel and aluminium alloy Al7075-T6 plate at different thickness combinations to necessitate the weight reduction of existing armour steel plate. The numerical models of monolithic configuration, double-layered configuration and triple-layered configuration were developed using a commercial explicit finite element code and were impacted by 7.62 mm armour piercing projectile at velocity range of 900 to 950 m/s. The ballistic performance of each configuration plate in terms of ballistic limit velocity, penetration process and permanent deformation was quantified and considered. It was found that the monolithic panel of high-strength steel has the best ballistic performance among all panels, yet it has not caused any weight reduction in existing armour plate. As the weight reduction was increased from 20-30%, the double-layered configuration panels became less resistance to ballistic impact where only at 20% and 23.2% of weight reduction panel could stop the 950m/s projectile. The triple-layered configuration panels with similar areal density performed much better where all panels subjected to 20-30% weight reductions successfully stopped the 950 m/s projectile. Thus, triple-layered configurations are interesting option in designing a protective structure without sacrificing the performance in achieving weight reduction.

  20. Capabilities of Helmets for Preventing Head Injuries Induced by Ballistic Impacts

    Directory of Open Access Journals (Sweden)

    D.V. Balandin

    2004-01-01

    Full Text Available The limiting performance of ballistically loaded helmets designed to reduce head injuries is studied analytically. The projectile does not penetrate the helmet. This analysis evaluates the absolute minimum of the peak displacement of the helmet shell relative to the head, provided that criteria measuring the severity of head injuries lie within prescribed limits. Rather than optimize a specific design configuration, e.g. a viscoelastic foam liner, characteristics of a time-dependent force representing the helmet liner are calculated. The formulation reduces the limiting performance analysis to an optimal control problem.

  1. Modelling of fracture processes in the ballistic impact on ceramic armours

    International Nuclear Information System (INIS)

    Zaera, R.; Sanchez-Galvez, V.

    1997-01-01

    This work examines the essential physical processes in the perforation of metal backed ceramic armours which include projectile erosion, fracture of the ceramic tile and ductile deformation of the metal backing plate. The impact of projectiles onto alumina and aluminium nitride ceramic materials is studied experimentally and numerically. Observations were performed using an X-ray shadowgraph technique to obtain accurate data of the penetration process at different times. From the examination of computer simulations and corresponding impact experiments a simple analytical model is developed by assuming some hypotheses simplifying the actual mechanisms of the penetration process. Material description is simplified by using simple equations and a few material parameters easily obtained experimentally, such as the elastic modulus, the compressive and tensile strength and the rupture strain. (orig.)

  2. The impact of strength level on adaptations to combined weightlifting, plyometric, and ballistic training.

    Science.gov (United States)

    James, L P; Gregory Haff, G; Kelly, V G; Connick, M J; Hoffman, B W; Beckman, E M

    2017-12-27

    The purpose of this investigation was to determine whether the magnitude of adaptation to integrated ballistic training is influenced by initial strength level. Such information is needed to inform resistance training guidelines for both higher- and lower-level athlete populations. To this end, two groups of distinctly different strength levels (stronger: one-repetition-maximum (1RM) squat = 2.01 ± 0.15 kg·BM -1 ; weaker: 1.20 ± 0.20 kg·BM -1 ) completed 10 weeks of resistance training incorporating weightlifting derivatives, plyometric actions, and ballistic exercises. Testing occurred at pre-, mid-, and post-training. Measures included variables derived from the incremental-load jump squat and the 1RM squat, alongside muscle activity (electromyography), and jump mechanics (force-time comparisons throughout the entire movement). The primary outcome variable was peak velocity derived from the unloaded jump squat. It was revealed that the stronger group displayed a greater (P = .05) change in peak velocity at mid-test (baseline: 2.65 ± 0.10 m/s, mid-test: 2.80 ± 0.17 m/s) but not post-test (2.85 ± 0.18 m/s) when compared to the weaker participants (baseline 2.43 ± 0.09, mid-test. 2.47 ± 0.11, post-test: 2.61 ± 0.10 m/s). Different changes occurred between groups in the force-velocity relationship (P = .001-.04) and jump mechanics (P ≤ .05), while only the stronger group displayed increases in muscle activation (P = .05). In conclusion, the magnitude of improvement in peak velocity was significantly influenced by pre-existing strength level in the early stage of training. Changes in the mechanisms underpinning performance were less distinct. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Influence of Material Properties on the Ballistic Performance of Ceramics for Personal Body Armour

    Directory of Open Access Journals (Sweden)

    Christian Kaufmann

    2003-01-01

    Full Text Available In support of improved personal armour development, depth of penetration tests have been conducted on four different ceramic materials including alumina, modified alumina, silicon carbide and boron carbide. These experiments consisted of impacting ceramic tiles bonded to aluminum cylinders with 0.50 caliber armour piercing projectiles. The results are presented in terms of ballistic efficiency, and the validity of using ballistic efficiency as a measure of ceramic performance was examined. In addition, the correlation between ballistic performance and ceramic material properties, such as elastic modulus, hardness, spall strength and Hugoniot Elastic Limit, has been considered.

  4. Thermoplastic composites for ballistic application

    Science.gov (United States)

    Song, John Whachong

    2003-08-01

    Systematic studies of thermoplastic composites on ballistic impact failure and kinetic energy absorption mechanisms were examined on both semicrystalline and amorphous polymer matrix composites. By taking advantages of the nature of thermoplastic polymers, the main objective of this research was to develop armor grade composites with thermoplastic resin matrices through a understanding of the microscopic as well as macroscopic characteristics of the composites. In both semicrystalline neat resin and composites, the crystal formation and the degree of crystallinity of the polymer matrix were greatly influenced by processing conditions, especially, the cooling rate. As the cooling rate is decreased, more perfect crystal formation and amorphous rearrangements were evident vs cooling at higher rates. The relative degree of crystallinity of semicrystalline matrix composites was calculated using dynamic mechanical analysis (DMA). These values were in good agreement with neat resin values obtained via differantial scanning calorimeter (DSC). Unfortunately, the morphological perfection of the semicrystalline matrix exhibits negligible advantage on ballistic impact resistance. Failure of the composites under ballistic impact was localized and the kinetic energy absorption was low. Amorphous polymers were also greatly influenced by processing conditions. Furthermore, amorphous polymers exhibit large processing windows in terms of processing temperature, which allows the various processing manipulations for ballistic composite fabrication. As increasing processing temperature, glass transition temperature of the polymer and stiffness of the composite increased due to the morphological perfection and level of wetting, respectively. Ballistic impact resistance was found to be inversely proportional to the stiffness of the composites. Fiber wetting characteristics and polymer morphology changes during the cooling process are considered to be major contributors of this behavior

  5. Elevated Temperature Ballistic Impact Testing of PBO and Kevlar Fabrics for Application in Supersonic Jet Engine Fan Containment Systems

    Science.gov (United States)

    Pereira, J. Michael; Roberts Gary D.; Revilock, Duane M., Jr.

    1997-01-01

    Ballistic impact tests were conducted on fabric made from both Poly(phenylene benzobizoxazole) (PBO) and Kevlar 29 which were selected to be similar in weave pattern, areal density, and fiber denier. The projectiles were 2.54-cm- (1-in.-) long aluminum cylinders with a diameter of 1.27 cm (0.5 in.). The fabric specimens were clamped on four sides in a 30.5-cm- (12-in.-) square frame. Tests on PBO were conducted at room temperature and at 260 C (500 F). A number of PBO specimens were aged in air at 204 and 260 C (400 and 500 F) before impact testing. Kevlar specimens were tested only at room temperature and with no aging. The PBO absorbed significantly more energy than the Kevlar at both room and elevated temperatures. However, after aging at temperatures of 204 C (400 F) and above, the PBO fabric lost almost all of its energy absorbing ability. It was concluded that PBO fabric is not a feasible candidate for fan containment system applications in supersonic jet engines where operating temperatures exceed this level.

  6. Ballistic Limit of High-Strength Steel and Al7075-T6 Multi-Layered Plates Under 7.62-mm Armour Piercing Projectile Impact

    OpenAIRE

    Rahman,N. A.; Abdullah,S.; Zamri,W. F. H.; Abdullah,M. F.; Omar,M. Z.; Sajuri,Z.

    2016-01-01

    Abstract This paper presents the computational-based ballistic limit of laminated metal panels comprised of high strength steel and aluminium alloy Al7075-T6 plate at different thickness combinations to necessitate the weight reduction of existing armour steel plate. The numerical models of monolithic configuration, double-layered configuration and triple-layered configuration were developed using a commercial explicit finite element code and were impacted by 7.62 mm armour piercing projectil...

  7. Penetration resistance and ballistic-impact behavior of Ti/TiAl3 metal/intermetallic laminated composites (MILCs: A computational investigation

    Directory of Open Access Journals (Sweden)

    Jennifer S. Snipes

    2016-06-01

    Full Text Available A comprehensive computational engineering analysis is carried out in order to assess suitability of the Ti/TiAl3 metal/intermetallic laminated composites (MILCs for use in both structural and add-on armor applications. This class of composite materials consists of alternating sub-millimeter thick layers of Ti (the ductile and tough constituent and TiAl3 (the stiff and hard constituent. In recent years, this class of materials has been investigated for potential use in light-armor applications as a replacement for the traditional metallic or polymer-matrix composite materials. Within the computational analysis, an account is given to differing functional requirements for candidate materials when used in structural and add-on ballistic armor. The analysis employed is of a transient, nonlinear-dynamics, finite-element character, and the problem investigated involves normal impact (i.e. under zero obliquity angle of a Ti/TiAl3 MILC target plate, over a range of incident velocities, by a fragment simulating projectile (FSP. This type of analysis can provide more direct information regarding the ballistic limit of the subject armor material, as well as help with the identification of the nature and the efficacy of various FSP material-deformation/erosion and kinetic-energy absorption/dissipation phenomena and processes. The results obtained clearly revealed that Ti/TiAl3 MILCs are more suitable for use in add-on ballistic, than in structural armor applications.

  8. Ballistic impact velocity response of carbon fibre reinforced aluminium alloy laminates for aero-engine

    Science.gov (United States)

    Mohammed, I.; Abu Talib, A. R.; Sultan, M. T. H.; Saadon, S.

    2017-12-01

    Aerospace and other industries use fibre metal laminate composites extensively due to their high specific strength, stiffness and fire resistance, in addition to their capability to be tailored into different forms for specific purposes. The behaviours of such composites under impact loading is another factor to be considered due to the impacts that occur in take-off, landing, during maintenance and operations. The aim of the study is to determine the specific perforation energy and impact strength of the fibre metal laminates of different layering pattern of carbon fibre reinforced aluminium alloy and hybrid laminate composites of carbon fibre and natural fibres (kenaf and flax). The composites are fabricated using the hand lay-up method in a mould with high bonding polymer matrix and compressed by a compression machine, cured at room temperature for one day and post cure in an oven for three hours. The impact tests are conducted using a gun tunnel system with a flat cylindrical bullet fired using a helium gas at a distance of 14 inches to the target. Impact and residual velocity of the projectile are recorded by high speed video camera. Specific perforation energy of carbon fibre reinforced aluminium alloy (CF+AA) for both before and after fire test are higher than the specific perforation energy of the other composites considered before and after fire test respectively. CF +AA before fire test is 55.18% greater than after. The same thing applies to impact strength of the composites where CF +AA before the fire test has the highest percentage of 11.7%, 50.0% and 32.98% as respectively compared to carbon fibre reinforced aluminium alloy (CARALL), carbon fibre reinforced flax aluminium alloy (CAFRALL) and carbon fibre reinforced kenaf aluminium alloy (CAKRALL), and likewise for the composites after fire test. The considered composites in this test can be used in the designated fire zone of an aircraft engine to protect external debris from penetrating the engine

  9. Impact of ballistic body armour and load carriage on walking patterns and perceived comfort.

    Science.gov (United States)

    Park, Huiju; Branson, Donna; Petrova, Adriana; Peksoz, Semra; Jacobson, Bert; Warren, Aric; Goad, Carla; Kamenidis, Panagiotis

    2013-01-01

    This study investigated the impact of weight magnitude and distribution of body armour and carrying loads on military personnel's walking patterns and comfort perceptions. Spatio-temporal parameters of walking, plantar pressure and contact area were measured while seven healthy male right-handed military students wore seven different garments of varying weight (0.06, 9, 18 and 27 kg) and load distribution (balanced and unbalanced, on the front and back torso). Higher weight increased the foot contact time with the floor. In particular, weight placement on the non-dominant side of the front torso resulted in the greatest stance phase and double support. Increased plantar pressure and contact area observed during heavier loads entail increased impact forces, which can cause overuse injuries and foot blisters. Participants reported increasingly disagreeable pressure and strain in the shoulder, neck and lower back during heavier weight conditions and unnatural walking while wearing unbalanced weight distributed loads. This study shows the potentially synergistic impact of wearing body armour vest with differential loads on body movement and comfort perception. This study found that soldiers should balance loads, avoiding load placement on the non-dominant side front torso, thus minimising mobility restriction and potential injury risk. Implications for armour vest design modifications can also be found in the results.

  10. Environmental Impact Statement. Small Intercontinental Ballistic Missile Program. Malmstrom Air Force Base, Montana

    Science.gov (United States)

    1987-12-01

    was useful but not totally germane to the impact analysis in Chapter 4.0. At the same time, new material has been added to Chapter 3.0 in some areas...4.1.2-2 Military-Civilian Composition of Program Inmigration .............. 4-34 1990-2000 4.1.2-3 Great Falls Public Schools Projected Program...Proposed Action and Alternatives 1, 2, and 3 4.1.3-2 1990-2000 Small ICBM Population Inmigration for the ............... 4-63 Proposed Action and

  11. Modeling and Simulation of Ballistic Penetration of Ceramic-Polymer-Metal Layered Systems

    Directory of Open Access Journals (Sweden)

    J. D. Clayton

    2015-01-01

    Full Text Available Numerical simulations and analysis of ballistic impact and penetration by tungsten alloy rods into composite targets consisting of layers of aluminum nitride ceramic tile(s, polymer laminae, and aluminum backing are conducted over a range of impact velocities on the order of 1.0 to 1.2 km/s. Computational results for ballistic efficiency are compared with experimental data from the literature. Simulations and experiments both demonstrate a trend of decreasing ballistic efficiency with increasing impact velocity. Predicted absolute residual penetration depths often exceed corresponding experimental values. The closest agreement between model and experiment is obtained when polymer interfaces are not explicitly represented in the numerical calculations, suggesting that the current model representation of such interfaces may be overly compliant. The present results emphasize the importance of proper resolution of geometry and constitutive properties of thin layers and interfaces between structural constituents for accurate numerical evaluation of performance of modern composite protection systems.

  12. High velocity impact experiment (HVIE)

    Energy Technology Data Exchange (ETDEWEB)

    Toor, A.; Donich, T.; Carter, P.

    1998-02-01

    The HVIE space project was conceived as a way to measure the absolute EOS for approximately 10 materials at pressures up to {approximately}30 Mb with order-of-magnitude higher accuracy than obtainable in any comparable experiment conducted on earth. The experiment configuration is such that each of the 10 materials interacts with all of the others thereby producing one-hundred independent, simultaneous EOS experiments The materials will be selected to provide critical information to weapons designers, National Ignition Facility target designers and planetary and geophysical scientists. In addition, HVIE will provide important scientific information to other communities, including the Ballistic Missile Defense Organization and the lethality and vulnerability community. The basic HVIE concept is to place two probes in counter rotating, highly elliptical orbits and collide them at high velocity (20 km/s) at 100 km altitude above the earth. The low altitude of the experiment will provide quick debris strip-out of orbit due to atmospheric drag. The preliminary conceptual evaluation of the HVIE has found no show stoppers. The design has been very easy to keep within the lift capabilities of commonly available rides to low earth orbit including the space shuttle. The cost of approximately 69 million dollars for 100 EOS experiment that will yield the much needed high accuracy, absolute measurement data is a bargain!

  13. Assessment of Ballistic Performance for Transparent Material

    Directory of Open Access Journals (Sweden)

    Basim M. Fadhil

    2014-05-01

    Full Text Available A finite element method was used to investigate the ballistic behavior of Polymethylmethacrylate (PMMA under impact loading by spherical steel projectile with different ranges of velocities. Three different target thicknesses were used in the experimental and the numerical works. A mathematical model has been used for the ballistic limit based on the experimental results. It has been found that projectile velocity and target thickness play an important role in the ballistic behavior of PMMA. A good agreement was found between the numerical, experimental, and the analytical result.

  14. Analysis of behind the armor ballistic trauma.

    Science.gov (United States)

    Wen, Yaoke; Xu, Cheng; Wang, Shu; Batra, R C

    2015-05-01

    The impact response of body armor composed of a ceramic plate with an ultrahigh molecular weight polyethylene (UHMWPE) fiber-reinforced composite and layers of UHMWPE fibers shielding a block of ballistic gelatin has been experimentally and numerically analyzed. It is a surrogate model for studying injuries to human torso caused by a bullet striking body protection armor placed on a person. Photographs taken with a high speed camera are used to determine deformations of the armor and the gelatin. The maximum depth of the temporary cavity formed in the ballistic gelatin and the peak pressure 40mm behind the center of the gelatin front face contacting the armor are found to be, respectively, ~34mm and ~15MPa. The Johnson-Holmquist material model has been used to simulate deformations and failure of the ceramic. The UHMWPE fiber-reinforced composite and the UHMWPE fiber layers are modeled as linear elastic orthotropic materials. The gelatin is modeled as a strain-rate dependent hyperelastic material. Values of material parameters are taken from the open literature. The computed evolution of the temporary cavity formed in the gelatin is found to qualitatively agree with that seen in experiments. Furthermore, the computed time histories of the average pressure at four points in the gelatin agree with the corresponding experimentally measured ones. The maximum pressure at a point and the depth of the temporary cavity formed in the gelatin can be taken as measures of the severity of the bodily injury caused by the impact; e.g. see the United States National Institute of Justice standard 0101.06-Ballistic Resistance of Body Armor. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Explicit Finite Element Modeling of Multilayer Composite Fabric for Gas Turbine Engine Containment Systems, Phase II. Part 2; Ballistic Impact Testing

    Science.gov (United States)

    Revilock, D. M.; Pereira, J. M.

    2009-01-01

    This report summarizes the ballistic impact testing that was conducted to provide validation data for the development of numerical models of blade-out events in fabric containment systems. The ballistic impact response of two different fiber materials - Kevlar(TradeName) 49 and Zylon(TradeName) AS (as spun) was studied by firing metal projectiles into dry woven fabric specimens using a gas gun. The shape, mass, orientation, and velocity of the projectile were varied and recorded. In most cases, the tests were designed so the projectile would perforate the specimen, allowing measurement of the energy absorbed by the fabric. The results for both Zylon and Kevlar presented here represent a useful set of data for the purposes of establishing and validating numerical models to predict the response of fabrics under conditions that simulate those of a jet engine blade-release situation. In addition, some useful empirical observations were made regarding the effects of projectile orientation and the relative performance of the different fabric materials.

  16. Ballistic penetration of multi-layered ceramic/steel targets

    Science.gov (United States)

    Zavattieri, Pablo D.; Espinosa, Horacio D.

    2000-04-01

    The response of multi-layered ceramic/steel targets to high velocity impact and penetration has been investigated through experiments and finite element simulations. Damage quantification and the material stresses and velocity histories provided by experiments are used as constraints to be satisfied by numerical simulations of the ballistic penetration event. Experimental and numerical observations demonstrate that the penetration process does not strongly depend on the ceramic material as usually assumed by most investigators. Instead, local and global effects which are related to material performance and structural features have been found to be very important factors that affect the overall target performance. These findings show that meaningful light weight armor design can only be accomplished through a combined experimental/numerical study in which relevant ballistic materials and structures are simultaneously investigated.

  17. Ballistic Evaluation of 2060 Aluminum

    Science.gov (United States)

    2016-05-24

    compared with other ballistic- grade AAs, namely AA2195 and AA2139. The results of these experiments were used to derive the acceptance tables for AA2060...contributions of the following people who made this work possible: program lead Brian Placzankis of ARL’s Coatings, Corrosion and Engineered Polymers Branch...properties as the AA2195 alloy and therefore became the basis for a fiscal year 2012 OSD-funded DAC program to fully validate and ultimately transition

  18. Performance of natural curaua fiber-reinforced polyester composites under 7.62 mm bullet impact as a stand-alone ballistic armor

    Directory of Open Access Journals (Sweden)

    Fábio de Oliveira Braga

    2017-10-01

    Full Text Available A multilayered armor system (MAS is intended to personal protection against high kinetic energy ammunition. MAS layers are composed of materials such as a front ceramic and a back composite that must show both high impact resistance and low weight, usually conflicting characteristics. Synthetic fiber fabrics, such as Kevlar™ and Dyneema™, are the favorite materials to back the front ceramic, due to their high strength, high modulus and relatively low weight. Recently, composites reinforced with natural fibers have been considered as MAS second layer owing to their good performance associated with other advantages as being cheaper and environmentally friendly. Among the natural fibers, those extracted from the leaves of the Ananas erectifolius plant, known as curaua, stand out due to its exceptional high strength and high modulus. Thus, the objective of the present work is to evaluate the performance of curaua fiber-reinforced polyester composites subjected to ballistic impact of high energy 7.62 mm ammunition. Composites reinforced with 0, 10, 20 and 30 vol.% of curaua fibers were produced and stand-alone tested as armor target to evaluate the absorbed energy. Analysis of variance (Anova and Tukey's honest significant difference test (HSD made it possible to compare the results to Kevlar™ laminates. Among the tested materials, the 30 vol.% fiber composites were found to be the best alternative to Kevlar™. Keywords: Composite, Natural fiber, Curaua fiber, Ballistic test

  19. Ballistic Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Ballistic Test Facility is comprised of two outdoor and one indoor test ranges, which are all instrumented for data acquisition and analysis. Full-size aircraft...

  20. Viscoelastic shock wave in ballistic gelatin behind soft body armor.

    Science.gov (United States)

    Liu, Li; Fan, Yurun; Li, Wei

    2014-06-01

    Ballistic gelatins are widely used as a surrogate of biological tissue in blunt trauma tests. Non-penetration impact tests of handgun bullets on the 10wt% ballistic gelatin block behind soft armor were carried out in which a high-speed camera recorded the crater׳s movement and pressure sensors imbedded in the gelatin block recorded the pressure waves at different locations. The observed shock wave attenuation indicates the necessity of considering the gelatin׳s viscoelasticity. A three-element viscoelastic constitutive model was adopted, in which the relevant parameters were obtained via fitting the damping free oscillations at the beginning of the creep-mode of rheological measurement, and by examining the data of published split Hopkinson pressure bar (SHPB) experiments. The viscoelastic model is determined by a retardation time of 5.5×10(-5)s for high oscillation frequencies and a stress relaxation time of 2.0-4.5×10(-7)s for shock wave attenuation. Using the characteristic-line method and the spherical wave assumption, the propagation of impact pressure wave front and the subsequent unloading profile can be simulated using the experimental velocity boundary condition. The established viscoelastic model considerably improves the prediction of shock wave attenuation in the ballistic gelatin. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Laboratory Impact Experiments

    Science.gov (United States)

    Horanyi, M.; Munsat, T.

    2017-12-01

    The experimental and theoretical programs at the SSERVI Institute for Modeling Plasmas, Atmospheres, and Cosmic Dust (IMPACT) address the effects of hypervelocity dust impacts and the nature of the space environment of granular surfaces interacting with solar wind plasma and ultraviolet radiation. These are recognized as fundamental planetary processes due their role in shaping the surfaces of airless planetary objects, their plasma environments, maintaining dust haloes, and sustaining surface bound exospheres. Dust impacts are critically important for all airless bodies considered for possible human missions in the next decade: the Moon, Near Earth Asteroids (NEAs), Phobos, and Deimos, with direct relevance to crew and mission safety and our ability to explore these objects. This talk will describe our newly developed laboratory capabilities to assess the effects of hypervelocity dust impacts on: 1) the gardening and redistribution of dust particles; and 2) the generation of ionized and neutral gasses on the surfaces of airless planetary bodies.

  2. ballistic performance of a quenched and tempered steel against

    African Journals Online (AJOL)

    eobe

    conditions. Hardness is an important feature for the materials used for armour strategy [1-3]. Sangoy and others.[5]reported that high hardness of given armour steel directly determines the ballistic performance and perforation mode. Many studies on the ballistic impact behaviour of the steels revealed that relationship exists ...

  3. Is there ballistic transport in metallic nano-objects? Ballistic versus diffusive contributions

    International Nuclear Information System (INIS)

    Garcia, N; Bai Ming; Lu Yonghua; Munoz, M; Cheng Hao; Levanyuk, A P

    2007-01-01

    When discussing the resistance of an atomic-or nanometre-size contact we should consider both its ballistic and its diffusive contributions. But there is a contribution of the leads to the resistance of the contact as well. In this context, the geometry and the roughness of the surfaces limiting the system will contribute to the resistance, and these contributions should be added to the ideal ballistic resistance of the nanocontact. We have calculated, for metallic materials, the serial resistance of the leads arising from the roughness, and our calculations show that the ohmic resistance is as important as the ballistic resistance of the constriction. The classical resistance is a lower limit to the quantum resistance of the leads. Many examples of earlier experiments show that the mean free path of the transport electrons is of the order of the size of the contacts or the leads. This is not compatible with the idea of ballistic transport. This result may put in serious difficulties the current, existing interpretation of experimental data in metals where only small serial resistances compared with the ballistic component of the total resistance have been taken into account. The two-dimensional electron gas (2DEG) is also discussed and the serial corrections appear to be smaller than for metals. Experiments with these last systems are proposed that may reveal new interesting aspects in the physics of ballistic and diffusive transport

  4. Is there ballistic transport in metallic nano-objects? Ballistic versus diffusive contributions

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, N [Laboratorio de Fisica de Sistemas Pequenos y NanotecnologIa, Consejo Superior de Investigaciones CientIficas (CSIC), Madrid 28006 (Spain); Bai Ming [Laboratorio de Fisica de Sistemas Pequenos y NanotecnologIa, Consejo Superior de Investigaciones CientIficas (CSIC), Madrid 28006 (Spain); Lu Yonghua [Laboratorio de Fisica de Sistemas Pequenos y NanotecnologIa, Consejo Superior de Investigaciones CientIficas (CSIC), Madrid 28006 (Spain); Munoz, M [Laboratorio de Fisica de Sistemas Pequenos y NanotecnologIa, Consejo Superior de Investigaciones CientIficas (CSIC), Madrid 28006 (Spain); Cheng Hao [Laboratorio de Fisica de Sistemas Pequenos y NanotecnologIa, Consejo Superior de Investigaciones CientIficas (CSIC), Madrid 28006 (Spain); Levanyuk, A P [Fisintec Innovacion Tecnologica, Miraflores 65, Alcobendas, Madrid 28100 (Spain)

    2007-01-10

    When discussing the resistance of an atomic-or nanometre-size contact we should consider both its ballistic and its diffusive contributions. But there is a contribution of the leads to the resistance of the contact as well. In this context, the geometry and the roughness of the surfaces limiting the system will contribute to the resistance, and these contributions should be added to the ideal ballistic resistance of the nanocontact. We have calculated, for metallic materials, the serial resistance of the leads arising from the roughness, and our calculations show that the ohmic resistance is as important as the ballistic resistance of the constriction. The classical resistance is a lower limit to the quantum resistance of the leads. Many examples of earlier experiments show that the mean free path of the transport electrons is of the order of the size of the contacts or the leads. This is not compatible with the idea of ballistic transport. This result may put in serious difficulties the current, existing interpretation of experimental data in metals where only small serial resistances compared with the ballistic component of the total resistance have been taken into account. The two-dimensional electron gas (2DEG) is also discussed and the serial corrections appear to be smaller than for metals. Experiments with these last systems are proposed that may reveal new interesting aspects in the physics of ballistic and diffusive transport.

  5. Artifacts that mimic ballistic magnetoresistance

    International Nuclear Information System (INIS)

    Egelhoff, W.F. . E-mail : egelhoff@nist.gov; Gan, L.; Ettedgui, H.; Kadmon, Y.; Powell, C.J.; Chen, P.J.; Shapiro, A.J.; McMichael, R.D.; Mallett, J.J.; Moffat, T.P.; Stiles, M.D.; Svedberg, E.B.

    2005-01-01

    We have investigated the circumstances underlying recent reports of very large values of ballistic magnetoresistance (BMR) in nanocontacts between magnetic wires. We find that the geometries used are subject to artifacts due to motion of the wires that distort the nanocontact thereby changing its electrical resistance. Since these nanocontacts are often of atomic scale, reliable experiments would require stability on the atomic scale. No method for achieving such stability in macroscopic wires is apparent. We conclude that macroscopic magnetic wires cannot be used to establish the validity of the BMR effect

  6. Ballistic Phosphorene Transistor

    Science.gov (United States)

    2015-11-19

    satisfactory. W911NF-14-1-0572 -II 66414-EL-II.3 TO:(1) Electronics Division (Qiu, Joe) TITLE: Final Report: Ballistic Phosphorene Transistor (x) Material... Transistor ” as a STIP award for the period 09/1/2014 through 5/31/2015. The ARO program director responsible for the grant is Dr. Joe Qiu. The PI is Prof...UU 19-11-2015 1-Sep-2014 31-May-2015 Approved for Public Release; Distribution Unlimited Final Report: Ballistic Phosphorene Transistor The views

  7. Finite element simulations and experiments of ballistic impacts on high performance PE composite material

    NARCIS (Netherlands)

    Herlaar, K.; Jagt-Deutekom, M.J. van der; Jacobs, M.J.N.

    2005-01-01

    The use of lightweight composite armour concepts is essential for the protection of future combat systems, both vehicles and personal. The design of such armour systems is challenging due to the complex material behaviour. Finite element simulations can be used to help understand the important

  8. 24th International Symposium on Ballistics

    Science.gov (United States)

    2008-09-26

    2008s.ppt Experimental Set-up Reverse ballistics experiments Flash radiography used to measure position of nose and tail of rod versus time 3 IBS 2008s.ppt...s Ballistic Testing. [VC]max vs Velocity Thorax -Kevlar Thorax -Twaron Thorax -Zylon Abdomen-Kevlar Abdomen-Twaron Abdomen-Zylon 25% Severe Thoracic...Injury 25% Severe Abdominal Injury -20 -10 0 10 20 30 40 50 60 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 D is pl ac em en tm m Time sec Displacement vs Time Thorax

  9. Gun Internal Ballistics.

    Science.gov (United States)

    An approximate method of analysis is formulated for gun internal ballistics. The method is incorporated in a digital computer program which is...described. The validity of the method of analysis and computational procedure is substantiated by comparison of theoretical results with experimental

  10. Ballistic hole magnetic microscopy

    NARCIS (Netherlands)

    Haq, E.; Banerjee, T.; Siekman, M.H.; Lodder, J.C.; Jansen, R.

    2005-01-01

    A technique to study nanoscale spin transport of holes is presented: ballistic hole magnetic microscopy. The tip of a scanning tunneling microscope is used to inject hot electrons into a ferromagnetic heterostructure, where inelastic decay creates a distribution of electron-hole pairs.

  11. Ballistic Trauma: Lessons Learned from Iraq and Afghanistan

    Science.gov (United States)

    Shin, Emily H.; Sabino, Jennifer M.; Nanos, George P.; Valerio, Ian L.

    2015-01-01

    Management of upper extremity injuries secondary to ballistic and blast trauma can lead to challenging problems for the reconstructive surgeon. Given the recent conflicts in Iraq and Afghanistan, advancements in combat-casualty care, combined with a high-volume experience in the treatment of ballistic injuries, has led to continued advancements in the treatment of the severely injured upper extremity. There are several lessons learned that are translatable to civilian trauma centers and future conflicts. In this article, the authors provide an overview of the physics of ballistic injuries and principles in the management of such injuries through experience gained from military involvement in Iraq and Afghanistan. PMID:25685099

  12. Ballistic penetration test results for Ductal and ultra-high performance concrete samples.

    Energy Technology Data Exchange (ETDEWEB)

    Reinhart, William Dodd; Thornhill, Tom Finley, III (KTech)

    2010-03-01

    This document provides detailed test results of ballistic impact experiments performed on several types of high performance concrete. These tests were performed at the Sandia National Laboratories Shock Thermodynamic Applied Research Facility using a 50 caliber powder gun to study penetration resistance of concrete samples. This document provides test results for ballistic impact experiments performed on two types of concrete samples, (1) Ductal{reg_sign} concrete is a fiber reinforced high performance concrete patented by Lafarge Group and (2) ultra-high performance concrete (UHPC) produced in-house by DoD. These tests were performed as part of a research demonstration project overseen by USACE and ERDC, at the Sandia National Laboratories Shock Thermodynamic Applied Research (STAR) facility. Ballistic penetration tests were performed on a single stage research powder gun of 50 caliber bore using a full metal jacket M33 ball projectile with a nominal velocity of 914 m/s (3000 ft/s). Testing was observed by Beverly DiPaolo from ERDC-GSL. In all, 31 tests were performed to achieve the test objectives which were: (1) recovery of concrete test specimens for post mortem analysis and characterization at outside labs, (2) measurement of projectile impact velocity and post-penetration residual velocity from electronic and radiographic techniques and, (3) high-speed photography of the projectile prior to impact, impact and exit of the rear surface of the concrete construct, and (4) summarize the results.

  13. Firearms and Ballistics

    OpenAIRE

    BOLTON-KING, Rachel; Schulze, Johan

    2016-01-01

    Chapter 7 of the book entitled 'Practical Veterinary Forensics' aims to introduce forensic veterinarians to the scientific concepts underpinning the field of firearms and ballistics. This introduction will enable practitioners to understand wound formation depending on the firearm and ammunition used. \\ud \\ud Various types of firearms, modern firing mechanisms and ammunition will be explained, together with an introduction to the physical concepts underpinning the four main constituents of th...

  14. Supra-ballistic phonons

    International Nuclear Information System (INIS)

    Russell, F.M.

    1989-05-01

    Energetic particles moving with a solid, either from nuclear reactions or externally injected, deposit energy by inelastic scattering processes which eventually appears as thermal energy. If the transfer of energy occurs in a crystalline solid then it is possible to couple some of the energy directly to the nuclei forming the lattice by generating phonons. In this paper the transfer of energy from a compound excited nucleus to the lattice is examined by introducing a virtual particle Π. It is shown that by including a Π in the nuclear reaction a substantial amount of energy can be coupled directly to the lattice. In the lattice this particle behaves as a spatially localized phonon of high energy, the so-called supra-ballistic phonon. By multiple inelastic scattering the supra-ballistic phonon eventually thermalizes. Because both the virtual particle Π and the equivalent supra-ballistic phonon have no charge or spin and can only exist within a lattice it is difficult to detect other than by its decay into thermal phonons. The possibility of a Π removing excess energy from a compound nucleus formed by the cold fusion of deuterium is examined. (Author)

  15. Ballistic negatron battery

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, M.S.R. [Koneru Lakshmiah Univ.. Dept. of Electrical and Electronics Engineering, Green fields, Vaddeswaram (India)

    2012-07-01

    If we consider the Statistics there is drastic increase in dependence of batteries from year to year, due to necessity of power storage equipment at homes, power generating off grid and on grid Wind, PV systems, etc.. Where wind power is leading in renewable sector, there is a need to look at its development. Considering the scenario in India, most of the wind resource areas are far away from grid and the remaining areas which are near to grid are of low wind currents which is of no use connecting these equipment directly to grid. So, there is a need for a power storage utility to be integrated, such as the BNB (Ballistic Negatron Battery). In this situation a country like India need a battery which should be reliable, cheap and which can be industrialized. So this paper presents the concept of working, design, operation, adaptability of a Ballistic Negatron Battery. Unlike present batteries with low energy density, huge size, more weight, more charging time and low resistant to wear level, this Ballistic Negatron Battery comes with, 1) High energy storage capability (many multiples more than the present most advanced battery). 2) Very compact in size. 3) Almost negligible in weight compared to present batteries. 4) Charges with in very less time. 5) Never exhibits a wear level greater than zero. Seems like inconceivable but adoptable with simple physics. This paper will explains in detail the principle, model, design, construction and practical considerations considered in making this battery. (Author)

  16. Fracture behaviour of mullite fibre reinforced-mullite matrix composites under quasi-static and ballistic impact loading

    Czech Academy of Sciences Publication Activity Database

    Boccaccini, A. R.; Atiq, S.; Boccaccini, D. N.; Dlouhý, Ivo; Kaya, C.

    č. 65 (2005), s. 325-333 ISSN 0266-3538 R&D Projects: GA AV ČR IAA2041003 Keywords : ceramic matrix composites * mullite matrix * toughness Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.184, year: 2005

  17. The application of a calibrated 3D ballistic trajectory model to ballistic hazard assessments at Upper Te Maari, Tongariro

    Science.gov (United States)

    Fitzgerald, R. H.; Tsunematsu, K.; Kennedy, B. M.; Breard, E. C. P.; Lube, G.; Wilson, T. M.; Jolly, A. D.; Pawson, J.; Rosenberg, M. D.; Cronin, S. J.

    2014-10-01

    On 6 August, 2012, Upper Te Maari Crater, Tongariro volcano, New Zealand, erupted for the first time in over one hundred years. Multiple vents were activated during the hydrothermal eruption, ejecting blocks up to 2.3 km and impacting ~ 2.6 km of the Tongariro Alpine Crossing (TAC) hiking track. Ballistic impact craters were mapped to calibrate a 3D ballistic trajectory model for the eruption. This was further used to inform future ballistic hazard. Orthophoto mapping revealed 3587 impact craters with a mean diameter of 2.4 m. However, field mapping of accessible regions indicated an average of at least four times more observable impact craters and a smaller mean crater diameter of 1.2 m. By combining the orthophoto and ground-truthed impact frequency and size distribution data, we estimate that approximately 13,200 ballistic projectiles were generated during the eruption. The 3D ballistic trajectory model and a series of inverse models were used to constrain the eruption directions, angles and velocities. When combined with eruption observations and geophysical observations, the model indicates that the blocks were ejected in five variously directed eruption pulses, in total lasting 19 s. The model successfully reproduced the mapped impact distribution using a mean initial particle velocity of 200 m/s with an accompanying average gas flow velocity over a 400 m radius of 150 m/s. We apply the calibrated model to assess ballistic hazard from the August eruption along the TAC. By taking the field mapped spatial density of impacts and an assumption that an average ballistic impact will cause serious injury or death (casualty) over an 8 m2 area, we estimate that the probability of casualty ranges from 1% to 16% along the affected track (assuming an eruption during the time of exposure). Future ballistic hazard and probabilities of casualty along the TAC are also assessed through application of the calibrated model. We model a magnitude larger eruption and illustrate

  18. Ballistic Characterization Of A Typical Military Steel Helmet

    Directory of Open Access Journals (Sweden)

    Mohamed Ali Maher

    2017-08-01

    Full Text Available In this study the ballistic limit of a steel helmet against a FMJ 919 mm caliber bullet is estimated. The helmet model is the typical polish helmet wz.31.The helmet material showed high strength low alloy steel material of 0.28 carbon content and 9.125 kgm2 areal density. The tensile test according to ASTM E8 showed a tensile strength of 1236.4 MPa .The average hardness value was about HV550. First shooting experiment has been executed using a 9 mm pistol based on 350 ms muzzle velocity at 5m against the simply supported helmet complete penetrations rose in this test were in the form of cracks on the helmet surface and partial penetrations were in the form of craters on the surface whose largest diameter and depth were 43 mm and 20.2 mm consequently .The second experiment was on a rifled gun arrangement 13 bullets of 919 mm caliber were shot on the examined simply supported steel helmet at a zero obliquity angle at different velocities to determine the ballistic limit velocity V50 according to MIL-STD-662F. Three major outcomes were revealed 1 the value V50 which found to be about 390 ms is higher than the one found in literature 360 ms German steel helmet model 1A1. 2 The smallest the standard deviation of the mixed results zone data the most accurate the ballistic limit is. 3Similar to the performance of blunt-ended projectiles impacting overmatching targets tD near 11 or larger It was found that the dominating failure mode of the steel helmet stuck by a hemispherical-nose projectile was plugging mode despite of having tD ratio of about 19 undermatching.

  19. Capability of satellite-aided ballistic capture

    Science.gov (United States)

    Luo, Z.-F.; Topputo, F.

    2017-07-01

    In this paper we study a special instance of ballistic capture dynamics: the case in which the capture orbit about a planet experiences a close passage to one or more of its natural satellites. The capability of the satellites in improving ballistic capture is assessed. The dynamical framework considers at least the gravitational attractions of the Sun, the planet, and its satellites, all acting on a massless particle. The effect of the satellites is introduced explicitly by modifying a previously developed method, which relies on three-dimensional stable sets and n-body dynamics with precise ephemeris. Once a stability criterium is defined, initial conditions defined over a computational grid are integrated forward and backward. This allows us to classify orbits into different sets. Ballistic capture orbits with prescribed features are generated by manipulating these sets. Two indices, namely the hyperbolic velocity and the stability index, are used to assess the performance of pre- and post-capture portions, respectively. A Pareto frontier is used to extract orbits of practical interest. Case studies are performed in the context of Earth and Jupiter environments. Comparing to the situation with no moons, the satellite-aided ballistic capture can evidently increase the pre-capture energy and post-capture stability, so making it possible to have permanent capture of a particle at zero-cost. This is a desirable feature in mission design.

  20. The Ejecta Evolution of Deep Impact: Insight from Experiments

    Science.gov (United States)

    Hermalyn, B.; Schultz, P. H.; Heineck, J. T.

    2010-12-01

    The Deep Impact (DI) probe impacted comet 9P/Tempel 1 at an angle of ~30° from local horizontal with a velocity of 10.2 km/s. Examination of the resulting ballistic (e.g., non-vapor driven) ejecta revealed phenomena that largely followed expectations from laboratory investigations of oblique impacts into low-density porous material, including a downrange bias, uprange zone of avoidance, and cardioid (curved) rays (Schultz, et al, 2005, 2007). Modeling of the impact based on canonical models and scaling laws (Richardson, et al, 2007) allowed a first-order reconstruction of the event, but did not fully represent the three-dimensional nature of the ejecta flow-field in an oblique impact essential for interpretation of the DI data. In this study, we present new experimental measurements of the early-time ejecta dynamics in oblique impacts that allow a more complete reconstruction of the ballistic ejecta from the impact, including visualization of the DI encounter and predictions for the upcoming re-encounter with Tempel 1. A suite of hypervelocity 30° impact experiments into granular materials was performed at the NASA Ames Vertical Gun Range (AVGR) for the purpose of interpreting the Deep Impact event. A technique based on Particle Tracking Velocimetry (PTV) permitted non-intrusive measurement of the ejecta velocity within the ejecta curtain. The PTV system developed at the AVGR utilizes a laser light sheet projected parallel to the impact surface to illuminate horizontal “slices” of the ejecta curtain that are then recorded by multiple cameras. Particle displacement between successive frames and cameras allows determination of the three-component velocity of the ejecta curtain. Pioneering efforts with a similar technique (Anderson, et al, 2003, 2006) characterized the main-stage ejecta velocity distributions and demonstrated that asymmetries in velocity and ejection angle persist well into the far-field for oblique impacts. In this study, high-speed cameras

  1. Advanced prepreg ballistic composites for military helmets

    OpenAIRE

    Dimeski, Dimko; Srebrenkoska, Vineta

    2014-01-01

    With the advancement of ballistic materials and technologies, the ballistic prepregs are becoming an essential construction technique for getting the maximum performance out of the high performance fibers. The ballistic prepregs help to maximize the engagement between fibers and high speed projectiles penetrating the ballistic material, thus reducing the amount of ballistic material required to defeat the projectiles. The backbone of lightweight ballistic materials is high perform...

  2. Understanding the Ballistic Event: Methodology and Initial Observations

    OpenAIRE

    Healey, Adam; Cotton, J; Maclachlan, S; Smith, Paul; Yeomans, Julie

    2016-01-01

    The purpose of the study is to accelerate the development of ceramic materials for armour applications, by substantially increasing the information obtained from a high-energy projectile impact event. This has been achieved by modifying an existing test configuration to incorporate a block of ballistic gel, attached to the strike face of a ceramic armour system, to capture fragments generated during the ballistic event such that their final positions are maintained. Three different materials,...

  3. Global and local re-impact and velocity regime of ballistic ejecta of boulder craters on Ceres

    Science.gov (United States)

    Schulzeck, F.; Schröder, S. E.; Schmedemann, N.; Stephan, K.; Jaumann, R.; Raymond, C. A.; Russell, C. T.

    2018-04-01

    Imaging by the Dawn-spacecraft reveals that fresh craters on Ceres below 40 km often exhibit numerous boulders. We investigate how the fast rotating, low-gravity regime on Ceres influences their deposition. We analyze size-frequency distributions of ejecta blocks of twelve boulder craters. Global and local landing sites of boulder crater ejecta and boulder velocities are determined by the analytical calculation of elliptic particle trajectories on a rotating body. The cumulative distributions of boulder diameters follow steep-sloped power-laws. We do not find a correlation between boulder size and the distance of a boulder to its primary crater. Due to Ceres' low gravitational acceleration and fast rotation, ejecta of analyzed boulder craters (8-31 km) can be deposited across the entire surface of the dwarf planet. The particle trajectories are strongly influenced by the Coriolis effect as well as the impact geometry. Fast ejecta of high-latitude craters accumulate close to the pole of the opposite hemisphere. Fast ejecta of low-latitude craters wraps around the equator. Rotational effects are also relevant for the low-velocity regime. Boulders are ejected at velocities up to 71 m/s.

  4. Ballistic Missile Intercept from UCAV

    Science.gov (United States)

    2011-12-01

    on the DPRK TPD-2 ballistic missile. A 3 degree-of-freedom ( 3DoF ) mathematical model was previously developed and used to simulate the trajectory...Characteristics(estimated) TPD-2 ICBM Data Input to Simulation(From [1]) Figure 3. Reach of TPD-2 Missile A 3DoF ballistic missile

  5. Ballistic transport and electronic structure

    NARCIS (Netherlands)

    Schep, Kees M.; Kelly, Paul J.; Bauer, Gerrit E.W.

    1998-01-01

    The role of the electronic structure in determining the transport properties of ballistic point contacts is studied. The conductance in the ballistic regime is related to simple geometrical projections of the Fermi surface. The essential physics is first clarified for simple models. For real

  6. Ballistic performance of polyurea-coated armor grade ceramic tiles

    Science.gov (United States)

    Samiee, Ahsan; Isaacs, Jon; Nemat-Nasser, Sia

    2010-04-01

    The use of ceramics as energy absorbents has been studied by many researchers and some improvements in the ballistic performance of ceramic tiles have been made by coating them with different classes of materials (e.g. E-glass/epoxy, carbon-fiber/epoxy, etc.). Using ceramics for energy absorbing applications leads to a significant weight reduction of the system. Therefore, any modification to the ceramic configuration in the system which leads to more energy absorption with the same or less areal density is significant. On the other hand, polyurea has been proved to be an excellent energy dissipating agent in many applications. Inspired by this, we are studying the effect of coating ceramics with polyurea and other materials, on the energy absorption and ballistic performance of the resulting ceramic-based composites. In this study, we investigate the effect of polyurea on ballistic efficiency of ceramic tiles. To this end, we have performed a set of penetration tests on polyurea-ceramic composites. In our experiments, a high velocity projectile is propelled to impact and perforate the ceramic-polyurea composite. The velocity and mass of the projectile are measured before and after the penetration. The change in the kinetic energy of the projectile is evaluated and compared for different polyurea-ceramic configurations (e.g., polyurea on front face, polyurea on back face, polyurea between two ceramic tiles, etc.). The experimental results suggest that polyurea is not as effective as other restraining materials such as E-glass/epoxy and carbon-fiber/epoxy.

  7. Ballistic quality assurance

    International Nuclear Information System (INIS)

    Cassol, E.; Bonnet, J.; Porcheron, D.; Mazeron, J.J.; Peiffert, D.; Alapetite, C.

    2012-01-01

    This review describes the ballistic quality assurance for stereotactic intracranial irradiation treatments delivered with Gamma Knife R either dedicated or adapted medical linear accelerators. Specific and periodic controls should be performed in order to check the mechanical stability for both irradiation and collimation systems. If this step remains under the responsibility of the medical physicist, it should be done in agreement with the manufacturer's technical support. At this time, there are no recent published guidelines. With technological developments, both frequency and accuracy should be assessed in each institution according to the treatment mode: single versus hypo-fractionated dose, circular collimator versus micro-multi-leaf collimators. In addition, 'end-to-end' techniques are mandatory to find the origin of potential discrepancies and to estimate the global ballistic accuracy of the delivered treatment. Indeed, they include frames, non-invasive immobilization devices, localizers, multimodal imaging for delineation and in-room positioning imaging systems. The final precision that could be reasonably achieved is more or less 1 mm. (authors)

  8. Low-velocity impact cratering experiments in granular slopes

    Science.gov (United States)

    Hayashi, Kosuke; Sumita, Ikuro

    2017-07-01

    Low-velocity impact cratering experiments are conducted in sloped granular targets to study the effect of the slope angle θ on the crater shape and its scales. We use two types of granular matter, sand and glass beads, former of which has a larger friction coefficient μs = tanθr , where θr is the angle of repose. Experiments show that as θ increases, the crater becomes shallower and elongated in the direction of the slope. Furthermore the crater floor steepens in the upslope side and a thick rim forms in the downslope side, thus forming an asymmetric profile. High-speed images show that these features are results of ejecta being dispersed farther towards the downslope side and the subsequent avalanche which buries much of the crater floor. Such asymmetric ejecta dispersal can be explained by combining the Z-model and a ballistic model. Using the topographic maps of the craters, we classify crater shape regimes I-III, which transition with increasing θ : a full-rim crater (I), a broken-rim crater (II), and a depression (III). The critical θ for the regime transitions are larger for sand compared to glass beads, but collapse to close values when we use a normalized slope θ^ = tanθ / tanθr . Similarly we derive θ^-dependences of the scaled crater depth, length, width and their ratios which collapse the results for different targets and impact energies. We compare the crater profiles formed in our experiments with deep craters on asteroid Vesta and find that some of the scaled profiles nearly overlap and many have similar depth / length ratios. This suggests that these Vestan craters may also have formed in the gravity regime and that the formation process can be approximated by a granular flow with a similar effective friction coefficient.

  9. Ballistic impact on composite armour

    OpenAIRE

    Bourke, P

    2007-01-01

    Armoured vehicles in current military service are requiring ever more protection to enable them to carry out their mission in a safe, effective manner. This requirement is driving vehicle weight up to such an extent that the logistics of vehicle transport is becoming increasingly difficult. Composite materials are an important material group whose high specific properties can enable structures to be manufactured for a far lower weight than might otherwise be possible. Composite...

  10. Ballistic model to estimate microsprinkler droplet distribution

    Directory of Open Access Journals (Sweden)

    Conceição Marco Antônio Fonseca

    2003-01-01

    Full Text Available Experimental determination of microsprinkler droplets is difficult and time-consuming. This determination, however, could be achieved using ballistic models. The present study aimed to compare simulated and measured values of microsprinkler droplet diameters. Experimental measurements were made using the flour method, and simulations using a ballistic model adopted by the SIRIAS computational software. Drop diameters quantified in the experiment varied between 0.30 mm and 1.30 mm, while the simulated between 0.28 mm and 1.06 mm. The greatest differences between simulated and measured values were registered at the highest radial distance from the emitter. The model presented a performance classified as excellent for simulating microsprinkler drop distribution.

  11. Centrifuge impact cratering experiment 5

    Science.gov (United States)

    1984-01-01

    Transient crates motions, cratering flow fields, crates dynamics, determining impact conditions from total crater welt, centrifuge quarter-space cratering, and impact cratering mechanics research is documented.

  12. Thermodynamic properties of UF sub 6 measured with a ballistic piston compressor

    Science.gov (United States)

    Sterritt, D. E.; Lalos, G. T.; Schneider, R. T.

    1973-01-01

    From experiments performed with a ballistic piston compressor, certain thermodynamic properties of uranium hexafluoride were investigated. Difficulties presented by the nonideal processes encountered in ballistic compressors are discussed and a computer code BCCC (Ballistic Compressor Computer Code) is developed to analyze the experimental data. The BCCC unfolds the thermodynamic properties of uranium hexafluoride from the helium-uranium hexafluoride mixture used as the test gas in the ballistic compressor. The thermodynamic properties deduced include the specific heat at constant volume, the ratio of specific heats for UF6, and the viscous coupling constant of helium-uranium hexafluoride mixtures.

  13. Performance of lead-free versus lead-based hunting ammunition in ballistic soap.

    Directory of Open Access Journals (Sweden)

    Felix Gremse

    Full Text Available BACKGROUND: Lead-free hunting bullets are an alternative to lead-containing bullets which cause health risks for humans and endangered scavenging raptors through lead ingestion. However, doubts concerning the effectiveness of lead-free hunting bullets hinder the wide-spread acceptance in the hunting and wildlife management community. METHODS: We performed terminal ballistic experiments under standardized conditions with ballistic soap as surrogate for game animal tissue to characterize dimensionally stable, partially fragmenting, and deforming lead-free bullets and one commonly used lead-containing bullet. The permanent cavities created in soap blocks are used as a measure for the potential wound damage. The soap blocks were imaged using computed tomography to assess the volume and shape of the cavity and the number of fragments. Shots were performed at different impact speeds, covering a realistic shooting range. Using 3D image segmentation, cavity volume, metal fragment count, deflection angle, and depth of maximum damage were determined. Shots were repeated to investigate the reproducibility of ballistic soap experiments. RESULTS: All bullets showed an increasing cavity volume with increasing deposited energy. The dimensionally stable and fragmenting lead-free bullets achieved a constant conversion ratio while the deforming copper and lead-containing bullets showed a ratio, which increases linearly with the total deposited energy. The lead-containing bullet created hundreds of fragments and significantly more fragments than the lead-free bullets. The deflection angle was significantly higher for the dimensionally stable bullet due to its tumbling behavior and was similarly low for the other bullets. The deforming bullets achieved higher reproducibility than the fragmenting and dimensionally stable bullets. CONCLUSION: The deforming lead-free bullet closely resembled the deforming lead-containing bullet in terms of energy conversion

  14. Ballistic Trauma of Limbs

    Science.gov (United States)

    Lamah, Léopold; Keita, Damany; Marie Camara, Ibrahima; Lamine Bah, Mohamed; Sory, Sidimé; Diallo, Mamadou Moustapha

    2017-01-01

    The objective of our study was to report the management and follow-up of a particular case of ballistic trauma and to do the literature review. Observation: A 35-year-old patient, a trader who was the victim of a firearm accident under not very clear circumstances. He was admitted to the emergency department after 3 hours. Clinically, the patient had significant bleeding in the arm and was in a state of clouding of consciousness. We could notice on the right arm, a posterior large transfixing wound of 1 cm and a 6 cm one on the antero-internal side. The limb was cold with a small and thready pulse. Sensitivity was decreased in the radial nerve area. The radiograph showed bone comminution from the middle 1/3 to the superior 1/3 of the humeral diaphysis. The treatment was orthopedic (after debridement) by scapula-brachio-ante-brachiopalmar plaster splint with thoracic strap. The wound healed in 46 days and the patient resumed his activities after 11 months and 2 weeks. Conclusion: The authors presented the value of using the scapulo-brachio-palmar plaster splints with thoracic strap in some severe upper limb trauma in the absence of the external fixator. PMID:28567155

  15. Experimental investigation on ballistic stability of high-speed projectile in sand

    Science.gov (United States)

    Zhang, Wei; Qi, Yafei; Huang, Wei; Li, Dacheng; Hypervelocity Impact Research Center Team

    2015-06-01

    The investigation on ballistic stability of high-speed projectile in granular materials is important to the study of the earth penetrating weapon(EPW). Laboratory-scaled sand entry experiments for the trajectory in the sand have been performed with four different nosed projectiles at a range of velocities from 20 m/s to 250 m/s. The slender projectiles were designed into flat, ogival, hemi-sperical, truncated-ogival nose shapes to make comparisons on the trajectory when those projectiles were launched at vertical and oblique impact angles (0° ~ 25°) along a view window. A high-speed camera placed at the side of the window was employed to capture the entire process of projectiles' penetration. Basing on the comparison of different tests, theoretical analysis is carried out on the relationships between ballistic stability and associated conditions. It can be obtained that projectile with flat nose has the best ballistic stability, followed by truncated-ogival nose, and ogival nose is the least at the same velocity. Additionally, a semi-empirical model based on a corrected drag coefficient is established to predict the depth of penetration. National Natural Science Foundation of China (NO.: 11372088)

  16. Learning without knowing: subliminal visual feedback facilitates ballistic motor learning

    DEFF Research Database (Denmark)

    Lundbye-Jensen, Jesper; Leukel, Christian; Nielsen, Jens Bo

    by subconscious (subliminal) augmented visual feedback on motor performance. To test this, 45 subjects participated in the experiment, which involved learning of a ballistic task. The task was to execute simple ankle plantar flexion movements as quickly as possible within 200 ms and to continuously improve...... by the learner, indeed facilitated ballistic motor learning. This effect likely relates to multiple (conscious versus unconscious) processing of visual feedback and to the specific neural circuitries involved in optimization of ballistic motor performance.......). It is a well- described phenomenon that we may respond to features of our surroundings without being aware of them. It is also a well-known principle, that learning is reinforced by augmented feedback on motor performance. In the present experiment we hypothesized that motor learning may be facilitated...

  17. Sedimentological impacts of INDEX experiment

    Digital Repository Service at National Institute of Oceanography (India)

    Valsangkar, A.B.; Ambre, N.V.; Rodrigues, M.

    the disturber experiment suggest that noticeable changes occur in the sediment texture, clay mineralogy and grain size parameters. The grain size and mineralogical data has further been utilized in characterizing the sediment plume as well as its direction...

  18. Ballistic materials in MR imaging

    International Nuclear Information System (INIS)

    Smith, A.S.; Hurst, G.C.; Duerk, J.L.; Diaz, P.J.

    1990-01-01

    This paper reports on the most common ballistic materials available in the urban setting studied for deflection force, rotation, heating, and imaging artifact at 1.5 T to determine potential efficacy and safety for imaging patients with ballistic injuries. Twenty-eight missiles were tested, covering the range of bullet types and materials suggested by the Cleveland Police Department. Deflection force was measured by the New method. Rotation was studied by evaluating bullets in a 10% (W/W) ballistic gelating after 30 minutes with the long axis of the bullet placed parallel and perpendicular to the z axis. Heating was measured with alcohol thermometers imaged for 1 hour alternately with FESUM and spin-echo sequences (RF absorption w/Kg and 0.033 w/Kg). Image artifact evaluation of routine sequences was performed

  19. Ballistic Limit Equation for Single Wall Titanium

    Science.gov (United States)

    Ratliff, J. M.; Christiansen, Eric L.; Bryant, C.

    2009-01-01

    Hypervelocity impact tests and hydrocode simulations were used to determine the ballistic limit equation (BLE) for perforation of a titanium wall, as a function of wall thickness. Two titanium alloys were considered, and separate BLEs were derived for each. Tested wall thicknesses ranged from 0.5mm to 2.0mm. The single-wall damage equation of Cour-Palais [ref. 1] was used to analyze the Ti wall's shielding effectiveness. It was concluded that the Cour-Palais single-wall equation produced a non-conservative prediction of the ballistic limit for the Ti shield. The inaccurate prediction was not a particularly surprising result; the Cour-Palais single-wall BLE contains shield material properties as parameters, but it was formulated only from tests of different aluminum alloys. Single-wall Ti shield tests were run (thicknesses of 2.0 mm, 1.5 mm, 1.0 mm, and 0.5 mm) on Ti 15-3-3-3 material custom cut from rod stock. Hypervelocity impact (HVI) tests were used to establish the failure threshold empirically, using the additional constraint that the damage scales with impact energy, as was indicated by hydrocode simulations. The criterion for shield failure was defined as no detached spall from the shield back surface during HVI. Based on the test results, which confirmed an approximately energy-dependent shield effectiveness, the Cour-Palais equation was modified.

  20. Modeling of Quasi-ballistic transport in multi-gate MOSFET for circuit simulations

    International Nuclear Information System (INIS)

    Martinie, Sebastien

    2009-01-01

    Today, the MOSFET transistor reaches deca-nanometer dimensions for which the effects of ballistic transport can no longer be neglected. The challenge is therefore to be able to introduce (quasi-)ballistic transport in the modeling of new devices and evaluates its impact at the circuit level. In this context, our work focuses on the introduction of (quasi-)ballistic transport in compact model of multi-gate transistor for the simulation of circuit elements. Firstly, the McKelvey's method applied to MOSFET has been used to synthesize existing works on analytical modeling of ballistic / quasi-ballistic transport. Then, we built a macroscopic model called 'quasi-ballistic mobility' (starting from pioneering work of Rhew et al), following the comparison between the moment method and the McKelvey method to describe (quasi-)ballistic transport in TCAD environment. Secondly, results from this first model have led us to build our (quasi-)ballistic current by adapting or creating new approaches to take into account various effects of nano-scale devices: short-channel effects, quantum confinement and scattering mechanisms. Finally, our work investigates the impact of the transport properties on the performances of circuit operation. (author)

  1. Magnetic anisotropy and anisotropic ballistic conductance of thin magnetic wires

    International Nuclear Information System (INIS)

    Sabirianov, R.

    2006-01-01

    The magnetocrystalline anisotropy of thin magnetic wires of iron and cobalt is quite different from the bulk phases. The spin moment of monatomic Fe wire may be as high as 3.4 μ B , while the orbital moment as high as 0.5 μ B . The magnetocrystalline anisotropy energy (MAE) was calculated for wires up to 0.6 nm in diameter starting from monatomic wire and adding consecutive shells for thicker wires. I observe that Fe wires exhibit the change sign with the stress applied along the wire. It means that easy axis may change from the direction along the wire to perpendicular to the wire. We find that ballistic conductance of the wire depends on the direction of the applied magnetic field, i.e. shows anisotropic ballistic magnetoresistance. This effect occurs due to the symmetry dependence of the splitting of degenerate bands in the applied field which changes the number of bands crossing the Fermi level. We find that the ballistic conductance changes with applied stress. Even for thicker wires the ballistic conductance changes by factor 2 on moderate tensile stain in our 5x4 model wire. Thus, the ballistic conductance of magnetic wires changes in the applied field due to the magnetostriction. This effect can be observed as large anisotropic BMR in the experiment

  2. Ballistic behavior of ultra-high molecular weight polyethylene composite: effect of gamma radiation

    International Nuclear Information System (INIS)

    Alves, Andreia L. dos Santos; Nascimento, Lucio F.C.; Suarez, Joao C. Miguez; lucio2002bol.com.br

    2003-01-01

    Since World War II, textile composites have been used as ballistic armor. Ultra-high molecular weight polyethylene (UHMWPE) fibers are used in the production of armor materials. As they have been developed and commercialized only recently, there is not enough information about the effect of environmental agents in the ballistic performance of UHMWPE composites. In the present work, was evaluated the ballistic behavior of composite plates manufactured with UHMWPE fibers after exposure to gamma radiation. The ballistic tests results were related to the macromolecular alterations induced by the radiation through mechanical (hardness, impact and flexure) and physicochemical (Ftir/Mir. DSC and TGA) testing. It was observed that irradiation induces changes in the UHMWPE, degrading the ballistic performance of the composite. These results are presented and discussed. (author)

  3. Investigation on energy absorption efficiency of each layer in ballistic armour panel for applications in hybrid design

    OpenAIRE

    Yang, Yanfei; Chen, Xiaogang

    2017-01-01

    This study aims to reveal different energy absorption efficiency of each layer when armour panel is under ballistic impact. Through Finite Element (FE) modelling and ballistic tests, it is found that when fabrics are layered up in a panel, energy absorption efficiency is only 30%–60% of an individual fabric layer with free boundary condition. In addition, fabric layers in front, middle, and back exhibit different ballistic characteristics. Therefore, a new hybrid design principle has been pro...

  4. BALLISTIC RESISTANT ARTICLES COMPRISING TAPES

    NARCIS (Netherlands)

    VAN DER EEM, JORIS; HARINGS, JULES; JANSE, GERARDUS; TJADEN, HENDRIK

    2015-01-01

    The invention pertains to a ballistic-resistant moulded article comprising a compressed stack of sheets comprising reinforcing tapes having a tensile strength of at least 1.0 GPa, a tensile modulus of at least 40 GPa, and a tensile energy-to-break of at least 15 J/g, the direction of the tapes

  5. Optimization theory for ballistic conversion

    NARCIS (Netherlands)

    Xie, Yanbo; Versluis, Andreas Michel; van den Berg, Albert; Eijkel, Jan C.T.

    2016-01-01

    The growing demand of renewable energy stimulates the exploration of new materials and methods for clean energy. We recently demonstrated a high efficiency and power density energy conversion mechanism by using jetted charged microdroplets, termed as ballistic energy conversion. Hereby, we model and

  6. Simulating water distribution patterns for fixed spray plate sprinkler using the ballistic theory

    Directory of Open Access Journals (Sweden)

    Sofiane Ouazaa

    2014-07-01

    Full Text Available Ballistic simulation of the spray sprinkler for self-propelled irrigation machines requires the incorporation of the effect of the jet impact with the deflecting plate. The kinetic energy losses produced by the jet impact with the spray plate were experimentally characterized for different nozzle sizes and two working pressures for fixed spray plate sprinklers (FSPS. A technique of low speed photography was used to determine drop velocity at the point where the jet is broken into droplets. The water distribution pattern of FSPS for different nozzle sizes, working at two pressures and under different wind conditions were characterized in field experiments. The ballistic model was calibrated to simulate water distribution in different technical and meteorological conditions. Field experiments and the ballistic model were used to obtain the model parameters (D50, n, K1and K2. The results show that kinetic energy losses decrease with nozzle diameter increments; from 80% for the smallest nozzle diameter (2 mm to 45% for nozzle diameters larger than 5.1 mm, and from 80% for the smallest nozzle diameter (2 mm to 34.7% for nozzle diameters larger than 6.8 mm, at 138 kPa and 69 kPa working pressures, respectively. The results from the model compared well with field observations. The calibrated model has reproduced accurately the water distribution pattern in calm (r=0.98 and high windy conditions (r=0.76. A new relationship was found between the corrector parameters (K1’ and K2’ and the wind speed. As a consequence, model simulation will be possible for untested meteorological conditions.

  7. Finite element simulations and experiments to determine the residual damage of a CFRP composite material after ballistic impacts

    NARCIS (Netherlands)

    Herlaar, K.; Jagt-Deutekom, M. van der

    2005-01-01

    The use of lightweight systems is essential for future combat systems. More and more steel structures are replaced by composite structures. This also influences the vulnerability of the platform. A finite element material model is created in Autodyn of the carbon fiber reinforced plastic (CFRP)

  8. Planar impact experiments for EOS measurements

    International Nuclear Information System (INIS)

    Furnish, M.D.

    1993-01-01

    The community concerned with the numerical modeling of groundshock produced by underground nuclear tests must have access to materials data to benchmark models of rock behavior. Historically the primary source of these data has been planar impact experiments. These experiments have involved gun, explosive and electrical launchers. Other methods of introducing planar shocks include shock driving by in-contact explosives or laser bursts. This paper briefly describes gun launcher-based planar impact methods used to characterize geological materials at Sandia National Laboratories

  9. Ballistic study of Tensylon®–based panels

    Directory of Open Access Journals (Sweden)

    L-C. Alil

    2018-06-01

    Full Text Available Ballistic protection is a matter of interest requested by civilian as well as military needs. The last decade has witnessed an increase in the use of light weight and efficient armour systems. These panels may be used for body protection as well as light vehicle protection against small calibres or to enhance the protection level of heavier vehicles with decreasing or maintaining their weight penalty. Ultra high molecular weight polyethylene is a material of interest for light weight armour applications. The authors designed panels made of hot–pressed Tensylon® in different configurations with thin steel sheets as a backing and shield protection. Comparison of their ballistic performance to the theory predictions reveals the improved ballistic response of the panels. In addition, a non–pressed Tensylon® panel has been tested in order to facilitate the observations of the failure mechanisms inside the panels. Even if not suitable for practical use, such non–pressed panels clearly reveal the dynamic processes at micro–scale that occur during the impact. The failure mechanisms of the material under bullet penetration are discussed based on photography, optical microscopy and scanning electron microscopy. The supposed effects of the panel pressing are discussed based on the observed difference between pressed and non–pressed structures ballistic response.

  10. Laboratory experiments with impacting fuel rods

    International Nuclear Information System (INIS)

    Kiss, S.; Lipcsei, S.

    1994-10-01

    Vibration surveillance and diagnostics of fuel rods and fuel assemblies are important tasks in NPPs. Thus accurate knowledge of vibration phenomena and measurability is very important. Experimental results on models without limiter give good coincidence with theoretical calculations. Spectra measured on impacting rod become smoother with increasing impacting level. Spectra of fuel rods have a wider range in impacting rate and higher level of smoothing than spectra of model rod have. The impacting rate strongly depends on mechanical properties of the rod. By the experiments, one can state that as for Fourier spectra the only thing caused by the impacts is the smoothening. However, there is a chance to give faulty diagnosis by Fourier spectra only. Consequently, investigation of fuel rod vibration requires increased caution. (author) 4 refs.; 12 figs.; 1 tab

  11. Synchro-ballistic recording of detonation phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Critchfield, R.R.; Asay, B.W.; Bdzil, J.B.; Davis, W.C.; Ferm, E.N.; Idar, D.J.

    1997-09-01

    Synchro-ballistic use of rotating-mirror streak cameras allows for detailed recording of high-speed events of known velocity and direction. After an introduction to the synchro-ballistic technique, this paper details two diverse applications of the technique as applied in the field of high-explosives research. In the first series of experiments detonation-front shape is recorded as the arriving detonation shock wave tilts an obliquely mounted mirror, causing reflected light to be deflected from the imaging lens. These tests were conducted for the purpose of calibrating and confirming the asymptotic Detonation Shock Dynamics (DSD) theory of Bdzil and Stewart. The phase velocities of the events range from ten to thirty millimeters per microsecond. Optical magnification is set for optimal use of the film`s spatial dimension and the phase velocity is adjusted to provide synchronization at the camera`s maximum writing speed. Initial calibration of the technique is undertaken using a cylindrical HE geometry over a range of charge diameters and of sufficient length-to-diameter ratio to insure a stable detonation wave. The final experiment utilizes an arc-shaped explosive charge, resulting in an asymmetric detonation-front record. The second series of experiments consists of photographing a shaped-charge jet having a velocity range of two to nine millimeters per microsecond. To accommodate the range of velocities it is necessary to fire several tests, each synchronized to a different section of the jet. The experimental apparatus consists of a vacuum chamber to preclude atmospheric ablation of the jet tip with shocked-argon back lighting to produce a shadow-graph image.

  12. The usage of optical fibers for damage detection in ballistic protection composite laminates

    Directory of Open Access Journals (Sweden)

    Živković Irena D.

    2006-01-01

    Full Text Available This paper describes the procedure of embedding fiber optic sensors in laminar thermoplastic composite material, as well as damage investigation after ballistic loading. Thermoplastic-reinforced composite materials were made for increased material damage resistance during ballistic loading. Damage inside the composite material was detected by observing the intensity drop of the light signal transmitted through the optical fibers. Experimental testing was carried out in order to observe and analyze the response of the material under various load conditions. Different types of Kevlar reinforced composite materials (thermoplastic, thermo reactive and thermoplastic with ceramic plate as the impact face were made. Material damage resistance during ballistic loading was investigated and compared. Specimens were tested under multiple load conditions. The opto-electronic part of the measurement system consists of two light-emitting diodes as light sources for the optical fibers, and two photo detectors for the light intensity measurement. The output signal was acquired from photo detectors by means of a data acquisition board and personal computer. The measurements showed an intensity drop of the transmitted light signal as a result of the applied loading on composite structure for all the optical fibers. All the diagrams show similar behavior of the light signal intensity. In fact, all of them may be divided into three zones: the zone of penetration of the first composite layer, the bullet traveling zone through the composite material till its final stop, and the material relaxation zone. The attenuation of the light signal intensity during impact is caused by the influence of the applied dynamic stress on the embedded optical fibers. The applied stress caused micro bending of the optical fiber, changes in the shape of the cross-section and the unequal changes of the indices of refraction of the core and cladding due to the stress-optic effect. The

  13. Investigation about the influence of the mechanical properties of lead core and brass jacket of a NATO 7.62 mm ball bullet in numerical simulations of ballistic impacts

    Directory of Open Access Journals (Sweden)

    Scapin M.

    2012-08-01

    Full Text Available In the present work a validated numerical approach has been used in order to build a robust and reliable FE model of the impact of a NATO 7.62 mm ball bullet, against an aluminium transmission shaft. The bullet is a full metal jacket type, with a lead alloy core and a brass jacket. Target shaft is made by an Al6061-T6 aluminium alloy. According to the soft core (lead alloy of the bullet, most effort has been spent in order to evaluate the effect of bullet materials mechanical properties on the numerical results. Numerical analyses, carried out using the non-linear dynamic finite element solver Abaqus∖Explicit 6.10, have been performed focusing on core and jacket material behaviour (target material, Al6061-T6, has been previously calibrated by the authors. Thus numerical analyses have been performed considering for the mechanical behaviour of the bullet both a simplified approach (as reported in literature and new material data (with strain rate effect obtained by means of experimental tests on the two materials (lead and brass with specimens cut directly from the bullet. Finally the results of the analyses have been compared with real experimental ballistic tests.

  14. The Cooperative Ballistic Missile Defence Game

    NARCIS (Netherlands)

    Evers, L.; Barros, A.I.; Monsuur, H.

    2013-01-01

    The increasing proliferation of ballistic missiles and weapons of mass destruction poses new risks worldwide. For a threatened nation and given the characteristics of this threat a layered ballistic missile defence system strategy appears to be the preferred solution. However, such a strategy

  15. Temperature dependence of ballistic mobility in a metamorphic InGaAs/InAlAs high electron mobility transistor

    International Nuclear Information System (INIS)

    Lee, Jongkyong; Gang, Suhyun; Jo, Yongcheol; Kim, Jongmin; Woo, Hyeonseok; Han, Jaeseok; Kim, Hyungsang; Im, Hyunsik

    2014-01-01

    We have investigated the temperature dependence of ballistic mobility in a 100 nm-long InGaAs/InAlAs metamorphic high-electron-mobility transistor designed for millimeter-wavelength RF applications. To extract the temperature dependence of quasi-ballistic mobility, our experiment involves measurements of the effective mobility in the low-bias linear region of the transistor and of the collision-dominated Hall mobility using a gated Hall bar of the same epitaxial structure. The data measured from the experiment are consistent with that of modeled ballistic mobility based on ballistic transport theory. These results advance the understanding of ballistic transport in various transistors with a nano-scale channel length that is comparable to the carrier's mean free path in the channel.

  16. Asteroid deflection using a kinetic impactor: Insights from hypervelocity impact experiments

    Science.gov (United States)

    Hoerth, Tobias; Schäfer, Frank

    2016-04-01

    Within the framework of the planned AIDA mission [1], an impactor spacecraft (DART) hits the second component of the asteroid Didymos at hypervelocity. The impact crater will be observed from the AIM spacecraft and an observation of the ejecta plume is possible [1]. This allows conclusions to be drawn about the physical properties of the target material, and the momentum transfer will be studied [1]. In preparation for this mission, hypervelocity impact experiments can provide valuable information about the outcome of an impact event as a function of impactor and target material properties and, thus, support the interpretation of the data from the DART impact. In addition, these impact experiments provide an important means to validate numerical impact simulations required to simulate large-scale impacts that cannot be studied in laboratory experiments. Impact experiments have shown that crater morphology and size, crater growth and ejecta dynamics strongly depend on the physical properties of the target material [2]. For example, porous materials like sandstone lead to a shallower and slower ejection than low-porous materials like quartzite, and the cratering efficiency is reduced in porous targets leading to a smaller amount of ejected mass [3]. These phenomena result in a reduced momentum multiplication factor (often called "beta-value"), i.e. the ratio of the change in target momentum after the impact and the momentum of the projectile is smaller for porous materials. Hypervelocity impact experiments into target materials with different porosities and densities such as quartzite (2.9 %, 2.6 g/cm3), sandstone (25.3 %, 2 g/cm3), limestone (31 %, 1.8 g/cm3), and highly porous aerated concrete (87.5 %, 0.4 g/cm3) were conducted. Projectile velocities were varied between about 3 km/s and almost 7 km/s. A ballistic pendulum was used to measure the momentum transfer. The material strength required for scaling laws was determined for all target materials. The highest

  17. Natural Mallow Fiber-Reinforced Epoxy Composite for Ballistic Armor Against Class III-A Ammunition

    Science.gov (United States)

    Nascimento, Lucio Fabio Cassiano; Holanda, Luane Isquerdo Ferreira; Louro, Luis Henrique Leme; Monteiro, Sergio Neves; Gomes, Alaelson Vieira; Lima, Édio Pereira

    2017-10-01

    Epoxy matrix composites reinforced with up to 30 vol pct of continuous and aligned natural mallow fibers were for the first time ballistic tested as personal armor against class III-A 9 mm FMJ ammunition. The ballistic efficiency of these composites was assessed by measuring the dissipated energy and residual velocity after the bullet perforation. The results were compared to those in similar tests of aramid fabric (Kevlar™) commonly used in vests for personal protections. Visual inspection and scanning electron microscopy analysis of impact-fractured samples revealed failure mechanisms associated with fiber pullout and rupture as well as epoxy cracking. As compared to Kevlar™, the mallow fiber composite displayed practically the same ballistic efficiency. However, there is a reduction in both weight and cost, which makes the mallow fiber composites a promising material for personal ballistic protection.

  18. Ballistic representation for kinematic access

    Science.gov (United States)

    Alfano, Salvatore

    2011-01-01

    This work uses simple two-body orbital dynamics to initially determine the kinematic access for a ballistic vehicle. Primarily this analysis was developed to assess when a rocket body might conjunct with an orbiting satellite platform. A family of access opportunities can be represented as a volume for a specific rocket relative to its launch platform. Alternately, the opportunities can be represented as a geographical footprint relative to aircraft or satellite position that encompasses all possible launcher locations for a specific rocket. A thrusting rocket is treated as a ballistic vehicle that receives all its energy at launch and follows a coasting trajectory. To do so, the rocket's burnout energy is used to find its equivalent initial velocity for a given launcher's altitude. Three kinematic access solutions are then found that account for spherical Earth rotation. One solution finds the maximum range for an ascent-only trajectory while another solution accommodates a descending trajectory. In addition, the ascent engagement for the descending trajectory is used to depict a rapid access scenario. These preliminary solutions are formulated to address ground-, sea-, or air-launched vehicles.

  19. The Effects of PMMA on Ballistic Impact Performance of Hybrid Hard/Ductile All-Plastic- and Glass-Plastic-Based Composites

    Science.gov (United States)

    2004-02-01

    6 Figure 5. Typical conoid fracture pattern observed in the exit side of the PC-PMMA-PC laminate after impact...radial and circumferential cracks form over the PMMA plate in the PC-PMMA-PC laminates (figure 4). A conoid fracture pattern (figure 5) is evident in...generally recognized that the extent in the spreading of impact energy is closely related to the ability to form a conoid shaped damage zone within the

  20. Design Guide for Aerodynamics Testing of Earth and Planetary Entry Vehicles in a Ballistic Range

    Science.gov (United States)

    Bogdanoff, David W.

    2017-01-01

    The purpose of this manual is to aid in the design of an aerodynamics test of an earth or planetary entry capsule in a ballistic range. In this manual, much use is made of the results and experience gained in 50 years of ballistic range aerodynamics testing at the NASA Ames Research Center, and in particular, that gained in the last 27 years, while the author was working at NASA Ames. The topics treated herein include: Data to be obtained; flight data needed to design test; Reynolds number and dynamic similarity of flight trajectory and ballistic range test; capabilities of various ballistic ranges; Calculations of swerves due to average and oscillating lift and of drag-induced velocity decreases; Model and sabot design; materials, weights and stresses; Sabot separation; Launches at angle of attack and slapping with paper to produce pitch/yaw oscillations.

  1. Methodology to determine skull bone and brain responses from ballistic helmet-to-head contact loading using experiments and finite element analysis.

    Science.gov (United States)

    Pintar, Frank A; Philippens, Mat M G M; Zhang, JiangYue; Yoganandan, Narayan

    2013-11-01

    The objective of the study was to obtain helmet-to-head contact forces from experiments, use a human head finite element model to determine regional responses, and compare outputs to skull fracture and brain injury thresholds. Tests were conducted using two types of helmets (A and B) fitted to a head-form. Seven load cells were used on the head-form back face to measure helmet-to-head contact forces. Projectiles were fired in frontal, left, right, and rear directions. Three tests were conducted with each helmet in each direction. Individual and summated force- and impulse-histories were obtained. Force-histories were inputted to the human head-helmet finite element model. Pulse durations were approximately 4 ms. One-third force and impulse were from the central load cell. 0.2% strain and 40 MPa stress limits were not exceeded for helmet-A. For helmet-B, strains exceeded in left, right, and rear; pressures exceeded in bilateral directions; volume of elements exceeding 0.2% strains correlated with the central load cell forces. For helmet-A, volumes exceeding brain pressure threshold were: 5-93%. All elements crossed the pressure limit for helmet-B. For both helmets, no brain elements exceeded peak principal strain limit. These findings advance our understanding of skull and brain biomechanics from helmet-head contact forces. Published by Elsevier Ltd.

  2. Understanding the ballistic event : Methodology and observations relevant to ceramic armour

    Science.gov (United States)

    Healey, Adam

    The only widely-accepted method of gauging the ballistic performance of a material is to carry out ballistic testing; due to the large volume of material required for a statistically robust test, this process is very expensive. Therefore a new test, or suite of tests, that employ widely-available and economically viable characterisation methods to screen candidate armour materials is highly desirable; in order to design such a test, more information on the armour/projectile interaction is required. This work presents the design process and results of using an adapted specimen configuration to increase the amount of information obtained from a ballistic test. By using a block of ballistic gel attached to the ceramic, the fragmentation generated during the ballistic event was captured and analysed. In parallel, quasi-static tests were carried out using ring-on-ring biaxial disc testing to investigate relationships between quasi-static and ballistic fragment fracture surfaces. Three contemporary ceramic armour materials were used to design the test and to act as a baseline; Sintox FA alumina, Hexoloy SA silicon carbide and 3M boron carbide. Attempts to analyse the post-test ballistic sample non-destructively using X-ray computed tomography (XCT) were unsuccessful due to the difference in the density of the materials and the compaction of fragments. However, the results of qualitative and quantitative fracture surface analysis using scanning electron microscopy showed similarities between the fracture surfaces of ballistic fragments at the edges of the tile and biaxial fragments; this suggests a relationship between quasi-static and ballistic fragments created away from the centre of impact, although additional research will be required to determine the reason for this. Ballistic event-induced porosity was observed and quantified on the fracture surfaces of silicon carbide samples, which decreased as distance from centre of impact increased; upon further analysis this

  3. Rifle bullet penetration into ballistic gelatin.

    Science.gov (United States)

    Wen, Yaoke; Xu, Cheng; Jin, Yongxi; Batra, R C

    2017-03-01

    The penetration of a rifle bullet into a block of ballistic gelatin is experimentally and computationally studied for enhancing our understanding of the damage caused to human soft tissues. The gelatin is modeled as an isotropic and homogeneous elastic-plastic linearly strain-hardening material that obeys a polynomial equation of state. Effects of numerical uncertainties on penetration characteristics are found by repeating simulations with minute variations in the impact speed and the angle of attack. The temporary cavity formed in the gelatin and seen in pictures taken by two high speed cameras is found to compare well with the computed one. The computed time histories of the hydrostatic pressure at points situated 60 mm above the line of impact are found to have "two peaks", one due to the bullet impact and the other due to the bullet tumbling. Contours of the von Mises stress and of the effective plastic strain in the gelatin block imply that a very small region adjacent to the cavity surface is plastically deformed. The angle of attack is found to noticeably affect the penetration depth at the instant of the bullet tumbling through 90°. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Measurement of damage velocities in impacts of transparent armor

    International Nuclear Information System (INIS)

    Anderson, Charles E Jr; Bigger, Rory P; Weiss, Carl E

    2014-01-01

    A series of impact experiments were conducted to examine the response of transparent material to ballistic impact. The experiments consisted of impacting 15 mm of borosilicate glass bonded to 9.5 mm of Lexan. The projectile was a 0.30-cal hard steel bullet designed specifically for the experiments. High-speed imaging of the impact event and post-test analysis quantified damage propagation and the rate of propagation.

  5. Measurement of damage velocities in impacts of transparent armor

    Science.gov (United States)

    Anderson, Charles E., Jr.; Bigger, Rory P.; Weiss, Carl E.

    2014-05-01

    A series of impact experiments were conducted to examine the response of transparent material to ballistic impact. The experiments consisted of impacting 15 mm of borosilicate glass bonded to 9.5 mm of Lexan. The projectile was a 0.30-cal hard steel bullet designed specifically for the experiments. High-speed imaging of the impact event and post-test analysis quantified damage propagation and the rate of propagation.

  6. Ballistic transport in planetary ring systems due to particle erosion mechanisms. I - Theory, numerical methods, and illustrative examples

    Science.gov (United States)

    Durisen, Richard H.; Murphy, Brian W.; Cramer, Nichael Lynn; Cuzzi, Jeffrey N.; Mullikin, Thomas L.

    1989-01-01

    Ballistic transport, defined as the net radial transport of mass and angular momentum due to exchanges of meteoroid hypersonic-impact ejecta by neighboring planetary ring regions on time-scales orders-of-magnitude shorter than the age of the solar system, is presently considered as a problem in mathematical physics. The preliminary results of a numerical scheme for following the combined effects of ballistic transport and viscous diffusion demonstrate that ballistic transport generates structure near sharp edges already present in the ring-mass distribution; the entire ring system ultimately develops an undulatory structure whose length scale is typically of the order of the radial excursion of the impact ejecta.

  7. Modeling Ballistic Penetration of Multi-Layered Targets

    Science.gov (United States)

    Zavattieri, Pablo Daniel; Dante Espinosa, Horacio; Dwivedi, Sunil

    1999-06-01

    There have been several efforts to experimentally design suitable multi-layered ceramic targets. The focus of these experiments has been to minimize ceramic damage and flow to maximize penetration resistance. But the challenge of developing effective ceramic armor systems by experiments alone is a difficult task. In general, experiments do not always provide direct information on material behavior. The implementation of an iterative computational/experimental procedure requires reliable material models incorporating microfailure and macrofracture of ceramics and penetrator materials. A dynamic finite element analysis of large displacements, high strain rate deformation behavior of materials is presented in total lagrangian coordinates. An isochoric finite deformation plasticity model for metals, including rate and temperature effecs, and a continuum/discrete damage model capable of capturing fragmentation at two size scales is derived by combining continuum damage model and a discrete damage model for brittle failure. It is assumed that size and distribution of potential fragments are known a-priori, through either experimental findings or material properties, and that macrocracks can nucleate and propagate along the boundaries of these potential fragments. The finite deformation continuum multiple-plane microcracking damage model accounts for microcracks within fragments and interface elements, with cohesive strength, between potential fragments describe the behavior of macrocracks. A versatile adaptive remeshing technique has been implemented to have well conditioned fine mesh in zones with high rate of inelastic deformation and coarse mesh in zones with low rate of inelastic deformation. The results are presented for the ballistic penetration of multi-layered ceramic/steel targets using the above model. The effect of ceramic materials and target configuration design for ceramic confinement on the response of multi-layered targets subjected to high velocity

  8. The use of gelatine in wound ballistics research.

    Science.gov (United States)

    Carr, D J; Stevenson, T; Mahoney, P F

    2018-04-25

    Blocks of gelatine are used in both lethality and survivability studies for broadly the same reason, i.e. comparison of ammunition effects using a material that it is assumed represents (some part of) the human body. The gelatine is used to visualise the temporary and permanent wound profiles; elements of which are recognised as providing a reasonable approximation to wounding in humans. One set of researchers aim to improve the lethality of the projectile, and the other to understand the effects of the projectile on the body to improve survivability. Research areas that use gelatine blocks are diverse and include ammunition designers, the medical and forensics communities and designers of ballistic protective equipment (including body armour). This paper aims to provide an overarching review of the use of gelatine for wound ballistics studies; it is not intended to provide an extensive review of wound ballistics as that already exists, e.g. Legal Med 23:21-29, 2016. Key messages are that test variables, projectile type (bullet, fragmentation), impact site on the body and intermediate layers (e.g. clothing, personal protective equipment (PPE)) can affect the resulting wound profiles.

  9. Ballistic Rail Gun Soft Recovery Facility

    Data.gov (United States)

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

  10. Allegany Ballistics Lab: sensor test target system

    Science.gov (United States)

    Eaton, Deran S.

    2011-06-01

    Leveraging the Naval Surface Warfare Center, Indian Head Division's historical experience in weapon simulation, Naval Sea Systems Command commissioned development of a remote-controlled, digitally programmable Sensor Test Target as part of a modern, outdoor hardware-in-the-loop test system for ordnance-related guidance, navigation and control systems. The overall Target system design invokes a sciences-based, "design of automated experiments" approach meant to close the logistical distance between sensor engineering and developmental T&E in outdoor conditions over useful real world distances. This enables operating modes that employ broad spectrum electromagnetic energy in many a desired combination, variably generated using a Jet Engine Simulator, a multispectral infrared emitter array, optically enhanced incandescent Flare Simulators, Emitter/Detector mounts, and an RF corner reflector kit. As assembled, the recently tested Sensor Test Target prototype being presented can capably provide a full array of useful RF and infrared target source simulations for RDT&E use with developmental and existing sensors. Certain Target technologies are patent pending, with potential spinoffs in aviation, metallurgy and biofuels processing, while others are variations on well-established technology. The Sensor Test Target System is planned for extended installation at Allegany Ballistics Laboratory (Rocket Center, WV).

  11. Inelastic deformation and failure of tungsten carbide under ballistic-loading conditions

    NARCIS (Netherlands)

    Hazell, P.J.; Appleby-Thomas, G.J.; Herlaar, K.; Painter, J.

    2010-01-01

    High-speed photography has been used to investigate the dynamic behaviour of similar grades of WC-Co hardmetals during ballistic impacts with velocities in the range of 28-484. m/s. Key features of the failure of similar grades of WC-Co materials during complimentary impacts have been observed and

  12. Effect of tempering time on the ballistic performance of a high strength armour steel

    OpenAIRE

    Pradipta Kumar Jena; Ponguru Senthil P.; Siva Kumar K.

    2016-01-01

    The investigation describes and analyses the effect of tempering time on the mechanical and ballistic performance of a high strength armour steel. The steel is subjected to tempering at 300 °C for 2, 24 and 48 h. A marginal variation in strength and hardness is observed with increase in tempering time, whereas ductility and Charpy impact values are found to be decreasing. Ballistic performance of the samples are evaluated by impacting 7.62 mm and 12.7 mm armour piercing projectiles at 0° angl...

  13. Clustered impacts - Experiments and implications. [cratering mechanics

    Science.gov (United States)

    Schultz, P. H.; Gault, D. E.

    1985-01-01

    The characteristics of impact by clusters of projectiles are experimentally studied by launching grouped projectiles of aluminum shot, steel shot, iron filings, and sand. Cratering efficiency is considered as a function of a dimensionless parameter related to projectile size and impact velocity. The effects of different target and projectile densities on cratering efficiency are examined. Crater morphology is addressed by considering a typical example, reviewing the systematics between cluster dispersion and crater morphology for vertical impacts, and examining oblique angle impacts which have relevance for planetary secondary cratering processes. These results are compared with impacts by single bodies with different strengths. The evolution of the ejecta plume for clustered impacts is compared to that for single-body impacts for vertical and oblique impacts from 1.3 to 1.8 km/s. The experimental results are discussed in the context of planetary surface processes, emphasizing processes in an atmosphere-free environment and secondary impact cratering.

  14. Diffusing-wave spectroscopy of cold atoms in ballistic motion

    Science.gov (United States)

    Eloy, Aurélien; Yao, Zhibin; Bachelard, Romain; Guerin, William; Fouché, Mathilde; Kaiser, Robin

    2018-01-01

    Diffusing-wave spectroscopy is a powerful technique which consists in measuring the temporal correlation function of the intensity of light multiply scattered by a medium. In this paper, we apply this technique to cold atoms under purely ballistic motion and we investigate the transition between the single and the multiple-scattering regime. The intensity correlation function changes from a simple Gaussian function, whose width reveals the sample temperature, to a more complex decay shortened by the frequency redistribution in the thick cloud. These features are quantitatively compared to simulations with a phase-coherent and an incoherent model. Both show a very good agreement with the experiments.

  15. Ballistic Characterization Of A Typical Military Steel Helmet

    OpenAIRE

    Mohamed Ali Maher; Dr. Osama Mounir Dawood; Dr. Nabil El Houseiny Awad; Mahmoud Mohamed Younes

    2017-01-01

    In this study the ballistic limit of a steel helmet against a FMJ 919 mm caliber bullet is estimated. The helmet model is the typical polish helmet wz.31.The helmet material showed high strength low alloy steel material of 0.28 carbon content and 9.125 kgm2 areal density. The tensile test according to ASTM E8 showed a tensile strength of 1236.4 MPa .The average hardness value was about HV550. First shooting experiment has been executed using a 9 mm pistol based on 350 ms muzzle velocity at 5m...

  16. Ballistic behaviour of ultra-high molecular weight polyethylene: effect of gamma radiation

    International Nuclear Information System (INIS)

    Alves, Andreia L.S.; Nascimento, Lucio F.C.; Miguez Suarez, Joao Carlos

    2004-01-01

    The fiber reinforced polymer matrix composites (PMCs) are considered excellent engineering materials. In structural applications, when a high strength-to-weight ratio is fundamental for the design, PMCs are successfully replacing many conventional materials. Since World War II textile materials have been used as ballistic armor. Materials manufactured with ultrahigh molecular weight polyethylene (UHMWPE) fibers are used in the production of armor materials, for personnel protection and armored vehicles. As these have been developed and commercialized more recently, there is not enough information about the action of the ionizing radiation in the ballistic performance of this armor material. In the present work the ballistic behavior of composite plates manufactured with ultrahigh molecular weight polyethylene (UHMWPE) fibers were evaluated after exposure to gamma radiation. The ballistic tests results were related to the macromolecular modifications induced by the environmental degradation through mechanical (hardness, impact and flexure) and physicochemical (infrared spectroscopy, differential scanning calorimetry and thermal gravimetric analysis) tests. Our results indicate that gamma irradiation induces modifications in the UHMWPE macromolecular chains, altering the mechanical properties of the composite and decreasing, for higher radiation doses, its ballistic performance. These results are presented and discussed. (author)

  17. Ballistic Behaviour of Tempered Steel Armour Plates under Plane Strain Condition .

    OpenAIRE

    S. N. Dikshit

    1998-01-01

    The present investigation deals with the ballistic behaviour of tempered steel armour plates under plane strain condition at normal angle of attack. A conical-shaped steel projectile of 6.1 mmdiameter was impacted on 20 mm thick steel annour plates of 350, 450 and 550 Hv hardness, in the velocity range 200 -700 m/s at zero obliquity. Ballistic performance measured in terms of the depthof penetration indicates that, under plane strain condition, behavio1Do" f 550 Hv steel plate is better than ...

  18. Considerations on Dop (Depth Of Penetration) Test for Evaluation of Ceramics Materials Used in Ballistic Protection

    Science.gov (United States)

    Popa, Ioan-Dan; Dobriţa, Florin

    2017-12-01

    Tremendous amount of funds and other resorces were invested in studying the response of ceramic materials under ballistic impact, the main goal being to find a way to increase the protection of soldiers and the vehicles used in the modern battlespace. Using of ceramic materials especially carbon based (carbides), nitrogen based (nitrides) and oxygen based (oxides) ceramics in order to increase the protection level of ballistic equipment could be, sometimes, a big challenge when trying to use the proper test in order to evaluate and compare their performances. The role of the tests is to provide a better understanding of their response in different situations and, as a consequence, to make them more efficient as armour components through future improvements. The paper presents shortly the main tests which are used and eventually standardised for evaluating the ballistic behaviour of the ceramics and other armour components, with a special focus to DOP (Depth of Penetration) Tests.

  19. Deep-sea impact experiments and their future requirements

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, R.

    of biomass, followed by gradual restoration. Important results have been obtained from these experiments, but in order to have a better understanding of the impacts and restoration processes, it will be necessary to improvise future experiments to resemble...

  20. Shape of scoria cones on Mars: Insights from numerical modeling of ballistic pathways

    Czech Academy of Sciences Publication Activity Database

    Brož, Petr; Čadek, O.; Hauber, E.; Rossi, A. P.

    2014-01-01

    Roč. 406, November (2014), s. 14-23 ISSN 0012-821X Institutional support: RVO:67985530 Keywords : Mars * explosive volcanism * scoria cone * ballistic pathway Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 4.734, year: 2014

  1. A discussion on the usefulness of a shared European ballistic image database.

    Science.gov (United States)

    De Ceuster, J; Hermsen, R; Mastaglio, M; Nennstiel, R

    2012-12-01

    The introduction of electronic systems into the comparison of weapon marks in the mid 1990s caused a revolution in the discipline of "forensic ballistics". Most European states now use this technology to search their national open case files. Globalisation of crime and the loss of effective border controls have made the idea of a unified European ballistic system seem logical. The article critically considers the requirements and possible outcomes of such a system. Based on the experience of forensic practitioners it seems probable that a shared European electronic ballistic system will be of a very limited value at present. Further improvements of existing systems to reach compatibility are encouraged. Copyright © 2011 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

  2. Area Ballistic Missile Defense Coordinator and the Airborne Laser: Creating Ballistic Missile Defense Unity of Effort

    National Research Council Canada - National Science Library

    Oms, Pedro

    2003-01-01

    Theater Ballistic Missile Defense (TBMD) is a challenging mission area for any Theater Combatant or Joint Task Force Commander, and one he must focus on to mitigate the strategic effects this "terror" weapon can impart...

  3. Ballistic transport in semiconductor nanostructures: From quasi ...

    Indian Academy of Sciences (India)

    By suitable design it is possible to achieve quasi-ballistic transport in semiconductor nanostructures over times up to the ps-range. Monte-Carlo simulations reveal that under these conditions phase-coherent real-space oscillations of an electron ensemble, generated by fs-pulses become possible in wide potential wells.

  4. The Internal Ballistics of an Air Gun

    Science.gov (United States)

    Denny, Mark

    2011-01-01

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

  5. Electron Interference in Ballistic Graphene Nanoconstrictions

    DEFF Research Database (Denmark)

    Baringhaus, Jens; Settnes, Mikkel; Aprojanz, Johannes

    2016-01-01

    We realize nanometer size constrictions in ballistic graphene nanoribbons grown on sidewalls of SiC mesa structures. The high quality of our devices allows the observation of a number of electronic quantum interference phenomena. The transmissions of Fabry-Perot-like resonances are probed...

  6. Ballistic transport in semiconductor nanostructures: From quasi ...

    Indian Academy of Sciences (India)

    Abstract. By suitable design it is possible to achieve quasi-ballistic transport in semi- conductor nanostructures over times up to the ps-range. Monte-Carlo simulations reveal that under these conditions phase-coherent real-space oscillations of an electron ensem- ble, generated by fs-pulses become possible in wide ...

  7. Optimization theory for ballistic energy conversion

    NARCIS (Netherlands)

    Xie, Yanbo; Versluis, Michel; Van Den Berg, Albert; Eijkel, Jan C.T.

    2016-01-01

    The growing demand of renewable energy stimulates the exploration of new materials and methods for clean energy. We recently demonstrated a high efficiency and power density energy conversion mechanism by using jetted charged microdroplets, termed as ballistic energy conversion. Hereby, we model and

  8. The educational impact of experience overseas.

    Science.gov (United States)

    Fox, Thomas A; Byrne, Ged; Byrne-Davis, Lucie M

    2017-05-09

    Health care professionals are increasingly seeking overseas experience as part of their training. In the UK and Ireland, spending time overseas is becoming increasingly common during the first few years of training, with 10.8 per cent of Foundation Year-2 (Postgraduate Year-2) doctors working outside the UK in 2015. Although we know that doctors in training are increasingly seeking overseas experience, the reasons behind this are unknown. Many travel with the intention of returning after a period of time. With medical 'gap years' becoming common, there is a need to understand the reasons behind this phenomenon and what doctors take away from their overseas experience. We interviewed 20 British and Irish doctors in training who had spent time working in another high-income country before choosing to return home. A qualitative study was conducted to explore their experiences and what they learned from them. Doctors in training reported choosing to travel overseas to experience living abroad, take a break from training and to help them decide on their specialty choice. Participants reported a positive experience, with increased motivation, a greater sense of perspective, increased confidence, improved clinical skills and a better-informed decision on which specialty they wished to pursue. Doctors in training are increasingly seeking overseas experience, the reasons behind this are unknown DISCUSSION: Working overseas can be a positive educational experience for doctors in training. Although increasing numbers of doctors are choosing to work abroad, many wish to return to their countries of origin to complete training, and doctors should not be discouraged from undertaking additional experience overseas. © 2017 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

  9. Experimental Determination of Ballistic Performance of Composite Material Kevlar 29 and Alumina Powder/ Epoxy by Spherical Projectile

    Directory of Open Access Journals (Sweden)

    Luay Hashem Abbud

    2016-12-01

    Full Text Available In this study, a response of hybrid composite laminate woven fiber Kevlar29 – Al2O3 Powder/ Epoxy subjected to high velocity impact loading is presented. The energy absorbed due to impact of small rigid projectile on composite materials targets is determined experimentally. The energy absorbed due to impact of hemispherical projectiles on the developed composite laminates is investigated. The results revealed the maximum ballistic limit at impact velocity is found to be 390.87 ± 6 m/s for an the 18 mm target thickness. The ballistic limit velocity predictions are based on the theoretical method presented from another article. The initial velocity and residual velocity results showed good is agreement compared with the predicted results of Ipson and Recht equations. With 5.4 % of accuracy based on the experimental value for the theoretical model for ballistic limit velocity.

  10. Environmental Impact Analysis Process Chemical Release Experiment

    National Research Council Canada - National Science Library

    1999-01-01

    The U.S. Air Force proposes to conduct an experiment to identify the potential environmental consequences of an inadvertent release of hydrazine rocket propellant in space, during orbital or suborbital operations...

  11. Looking at Gestalt Group Impact: An Experiment.

    Science.gov (United States)

    Serok, Shraga; Bar, Ruth

    1984-01-01

    Tested the impact of gestalt group therapy on aspects of self-concept in graduate students (N=33). Results showed a significant rise in decisiveness, general adaptation and self-criticism in the gestalt group as compared to the control groups and showed no significant changes in the self-identification and self-acceptance parameters. (LLL)

  12. Clinical aspects of ballistic peripheral nerve injury: shrapnel versus gunshot.

    Science.gov (United States)

    Rochkind, Shimon; Strauss, Ido; Shlitner, Zvi; Alon, Malvina; Reider, Evgeny; Graif, Moshe

    2014-08-01

    Ballistic injuries to peripheral nerves pose special challenges in terms of indications, timing and type of surgical intervention. The aim of the present work was to analyze our experience in the surgical treatment of peripheral nerve ballistic injuries with respect to the mechanism of injury (gunshot versus shrapnel), and identify common and dissimilar prognostic factors in both types of injury. This study was conducted on 42 patients totaling 58 nerves. Twenty-two patients (32 nerves) were injured by gunshot and 20 patients (26 nerves) by shrapnel. Median postoperative follow-up was 33 months (range 12 months to 14 years). Overall postoperative outcome appears to be more favorable for gunshot-wound (GSW) patients than shrapnel-injured patients, especially in terms of neuropathic pain relief (75 % vs. 58 % respectively, p Nerve graft reconstruction, rather than neurolysis, seems to be the more beneficial treatment for shrapnel-induced neuropathic pain (100 % vs. 47 % in improvement rate, respectively). Early surgical intervention (median 2 months after injury) significantly relieved neuropathic pain in 83 % of shrapnel-injured patients compared to 58 % in patients operated later. This study suggests that shrapnel injury is more destructive for nerve tissue than gunshot injury. Our impression is that early surgical intervention in shrapnel injuries and split nerve grafting (especially when small fragments are recognized in the nerve) significantly improve the patient's functional activity and quality of life.

  13. The Anti-Ballistic Missile Treaty

    International Nuclear Information System (INIS)

    Platt, A.

    1991-01-01

    This paper reports that in late May 1972 former President Richard M. Nixon went to Moscow and signed, among other documents, a Treaty to Limit Anti-Ballistic Missile (ABM) Systems. Under this agreement, both the United States and the Soviet Union made a commitment not to build nationwide ABM defenses against the other's intercontinental and submarine-launched ballistic missiles. They agreed to limit ABM deployments to a maximum of two sites, with no more than 100 launchers per site. Thirteen of the treaty's sixteen articles are intended to prevent any deviation from this. In addition, a joint Standing Consultative Commission to monitor compliance was created. National technical means --- sophisticated monitoring devices on land, sea, and in space --- were to be the primary instruments used to monitor compliance with the treaty. The ABM Treaty was signed in conjunction with an Interim Agreement to Limit Strategic Offensive Arms

  14. Orbital magnetism in ensembles of ballistic billiards

    International Nuclear Information System (INIS)

    Ullmo, D.; Richter, K.; Jalabert, R.A.

    1993-01-01

    The magnetic response of ensembles of small two-dimensional structures at finite temperatures is calculated. Using semiclassical methods and numerical calculation it is demonstrated that only short classical trajectories are relevant. The magnetic susceptibility is enhanced in regular systems, where these trajectories appear in families. For ensembles of squares large paramagnetic susceptibility is obtained, in good agreement with recent measurements in the ballistic regime. (authors). 20 refs., 2 figs

  15. Lightweight Multifunctional Linear Cellular Alloy Ballistic Structures

    Science.gov (United States)

    2006-04-26

    densities of 10, 15 and 20 % with the dimensions shown in Table 1. The alloy compositions were high strength maraging steel (M200) and Super Invar ... alloys made from LCA processing3 are shown in Table 3. Super Invar in the as-reduced state is a ductile (25-30%) austenitic alloy . When cooled to...Final Report for Lightweight Multifunctional Linear Cellular Alloy Ballistic Structures from Structured Alloys , Inc. Joe K

  16. Modeling internal ballistics of gas combustion guns.

    Science.gov (United States)

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

    2016-05-01

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

  17. Targeting Low-Energy Ballistic Lunar Transfers

    Science.gov (United States)

    Parker, Jeffrey S.

    2010-01-01

    Numerous low-energy ballistic transfers exist between the Earth and Moon that require less fuel than conventional transfers, but require three or more months of transfer time. An entirely ballistic lunar transfer departs the Earth from a particular declination at some time in order to arrive at the Moon at a given time along a desirable approach. Maneuvers may be added to the trajectory in order to adjust the Earth departure to meet mission requirements. In this paper, we characterize the (Delta)V cost required to adjust a low-energy ballistic lunar transfer such that a spacecraft may depart the Earth at a desirable declination, e.g., 28.5(white bullet), on a designated date. This study identifies the optimal locations to place one or two maneuvers along a transfer to minimize the (Delta)V cost of the transfer. One practical application of this study is to characterize the launch period for a mission that aims to launch from a particular launch site, such as Cape Canaveral, Florida, and arrive at a particular orbit at the Moon on a given date using a three-month low-energy transfer.

  18. Specimen Alignment Technique for Oblique-Impact Shock Physics Experiments

    National Research Council Canada - National Science Library

    Cline, Tim

    2005-01-01

    .... This groove enables a projectile with a small protrusion, or key, to navel the length of the gun without rotating, permitting an angled front face of the projectile to properly impact a pre-aligned target. Precise alignment of the target with the angled front of the projectile is critical for a successful experiment. This technical note provides a detailed procedure for performing target alignment during oblique-impact experiments.

  19. Learning without knowing: subliminal visual feedback facilitates ballistic motor learning

    DEFF Research Database (Denmark)

    Lundbye-Jensen, Jesper; Leukel, Christian; Nielsen, Jens Bo

    received supraliminal as compared to subliminal feedback. In the 0 ms feedback group motor performance increased only slightly indicating an important role of augmented feedback in learning the ballistic task. In the two groups who received subliminal feedback none of the subjects were able to tell what...... by the learner, indeed facilitated ballistic motor learning. This effect likely relates to multiple (conscious versus unconscious) processing of visual feedback and to the specific neural circuitries involved in optimization of ballistic motor performance....

  20. Comparison of Impact Duration Between Experiment and Theory From Charpy Impact Test

    OpenAIRE

    Muhammad Said N.B.; Ali M.B.; Zakaria K.A.; Daud M.A.M.

    2016-01-01

    This study presents the comparison of impact duration between experiment and theory from impact signal through a Charpy test. Recently, the number of accidents on the highway has been increased and it depends on the impact duration of material that have the ability to provide adequate protection to passengers from harmful and improve occupant survivability during crash event. Charpy impact test was implemented on different material and thickness but at the same striker velocity. Impact signal...

  1. Impact Crater Experiments for Introductory Physics and Astronomy Laboratories

    Science.gov (United States)

    Claycomb, J. R.

    2009-01-01

    Activity-based collisional analysis is developed for introductory physics and astronomy laboratory experiments. Crushable floral foam is used to investigate the physics of projectiles undergoing completely inelastic collisions with a low-density solid forming impact craters. Simple drop experiments enable determination of the average acceleration,…

  2. Ceramic bar impact experiments for improved material model

    International Nuclear Information System (INIS)

    Brar, N.S.; Proud, W.G.; Rajendran, A.M.

    2004-01-01

    Ceramic bar-on-bar (uniaxial stress) experiments are performed to extend uniaxial strain deformation states imposed in flyer plate impact experiments. A number of investigators engaged in modeling the bar-on-bar experiments have varying degrees of success in capturing the observed fracture modes in bars and correctly simulating the measured in-situ axial stress or free surface velocity histories. The difficulties encountered are related to uncertainties in understanding the dominant failure mechanisms as a function of different stress states imposed in bar impacts. Free surface velocity of the far end of the target AD998 bar were measured using a VISAR in a series of bar-on-bar impact experiments at nominal impact speeds of 100 m/s, 220 m/s, and 300 m/s. Velocity history data at an impact of 100 m/s show the material response as elastic. At higher impact velocities of 200 m/s and 300 m/s the velocity history data suggest an inelastic material response. A high-speed (Imacon) camera was employed to examine the fracture and failure of impactor and target bars. High speed photographs provide comprehensive data on geometry of damage and failure patterns as a function of time to check the validity of a particular constitutive material model for AD998 alumina used in numerical simulations of fracture and failure of the bars on impact

  3. In-flight dynamics of volcanic ballistic projectiles

    Science.gov (United States)

    Taddeucci, J.; Alatorre-Ibargüengoitia, M. A.; Cruz-Vázquez, O.; Del Bello, E.; Scarlato, P.; Ricci, T.

    2017-09-01

    Centimeter to meter-sized volcanic ballistic projectiles from explosive eruptions jeopardize people and properties kilometers from the volcano, but they also provide information about the past eruptions. Traditionally, projectile trajectory is modeled using simplified ballistic theory, accounting for gravity and drag forces only and assuming simply shaped projectiles free moving through air. Recently, collisions between projectiles and interactions with plumes are starting to be considered. Besides theory, experimental studies and field mapping have so far dominated volcanic projectile research, with only limited observations. High-speed, high-definition imaging now offers a new spatial and temporal scale of observation that we use to illuminate projectile dynamics. In-flight collisions commonly affect the size, shape, trajectory, and rotation of projectiles according to both projectile nature (ductile bomb versus brittle block) and the location and timing of collisions. These, in turn, are controlled by ejection pulses occurring at the vent. In-flight tearing and fragmentation characterize large bombs, which often break on landing, both factors concurring to decrease the average grain size of the resulting deposits. Complex rotation and spinning are ubiquitous features of projectiles, and the related Magnus effect may deviate projectile trajectory by tens of degrees. A new relationship is derived, linking projectile velocity and size with the size of the resulting impact crater. Finally, apparent drag coefficient values, obtained for selected projectiles, mostly range from 1 to 7, higher than expected, reflecting complex projectile dynamics. These new perspectives will impact projectile hazard mitigation and the interpretation of projectile deposits from past eruptions, both on Earth and on other planets.

  4. Deterrence of ballistic missile systems and their effects on today's air operations

    Science.gov (United States)

    Durak, Hasan

    2015-05-01

    Lately, the effect-based approach has gained importance in executing air operations. Thus, it makes more successful in obtaining the desired results by breaking the enemy's determination in a short time. Air force is the first option to be chosen in order to defuse the strategic targets. However, the problems such as the defense of targets and country, radars, range…etc. becoming serious problems. At this level ballistic missiles emerge as a strategic weapon. Ultimate emerging technologies guided by the INS and GPS can also be embedded with multiple warheads and reinforced with conventional explosive, ballistic missiles are weapons that can destroy targets with precision. They have the advantage of high speed, being easily launched from every platform and not being easily detected by air defense systems contrary to other air platforms. While these are the advantages, there are also disadvantages of the ballistic missiles. The high cost, unavailability of nuclear, biological and chemical weapons, and its limited effect while using conventional explosives against destroying the fortified targets are the disadvantages. The features mentioned above should be considered as limitation to the impact of the ballistic missiles. The aim is to impose the requests on enemies without starting a war with all components and to ensure better implementation of the operation functions during the air operations. In this study, effects of ballistic missiles in the future on air battle theatre will be discussed in the beginning, during the process and at the end phase of air operations within the scope of an effect-based approach.

  5. Comparison of Impact Duration Between Experiment and Theory From Charpy Impact Test

    Directory of Open Access Journals (Sweden)

    Muhammad Said N.B.

    2016-01-01

    Full Text Available This study presents the comparison of impact duration between experiment and theory from impact signal through a Charpy test. Recently, the number of accidents on the highway has been increased and it depends on the impact duration of material that have the ability to provide adequate protection to passengers from harmful and improve occupant survivability during crash event. Charpy impact test was implemented on different material and thickness but at the same striker velocity. Impact signal is obtained through the strain gauge that has been installed to striker hammer and connected to frequency data acquisition system. Collected signal is then analysed to identify the time period during impact before fractured. Result from both experiment and theory shows an increment to the impact duration as thickness is increased. Charpy test shows that aluminium 6061-T6 has a higher impact duration compared to carbon steel 1050.

  6. Contemporary management of maxillofacial ballistic trauma.

    Science.gov (United States)

    Breeze, J; Tong, D; Gibbons, A

    2017-09-01

    Ballistic maxillofacial trauma in the UK is fortunately relatively rare, and generally involves low velocity handguns and shotguns. Civilian terrorist events have, however, shown that all maxillofacial surgeons need to understand how to treat injuries from improvised explosive devices. Maxillofacial surgeons in the UK have also been responsible for the management of soldiers evacuated from Iraq and Afghanistan, and in this review we describe the newer types of treatment that have evolved from these conflicts, particularly that of damage-control maxillofacial surgery. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  7. Modeling the Impact Ejected Dust Contribution to the Lunar Exosphere: Results from Experiments and Ground Truth from LADEE

    Science.gov (United States)

    Hermalyn, B.; Colaprete, A.

    2013-12-01

    A considerable body of evidence indicates the presence of lofted regolith dust above the lunar surface. These observations range from multiple in-situ and orbital horizon glow detections to direct measurement of dust motion on the surface, as by the Apollo 17 Lunar Ejecta and Meteorites (LEAM) experiment. Despite this evidence, the specific mechanisms responsible for the lofting of regolith are still actively debated. These include impact ejection, electrostatic lofting, effects of high energy radiation, UV/X- rays, and interplay with solar wind plasma. These processes are highly relevant to one of the two main scientific objectives of the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission (due to launch September, 2013): to directly measure the lunar exospheric dust environment and its spatial and temporal variability towards the goal of better understanding the dust flux. Of all the proposed mechanisms taking place on the lunar surface, the only unequivocal ongoing process is impact cratering. Hypervelocity impact events, which mobilize and redistribute regolith across planetary surfaces, are arguably the most pervasive geologic process on rocky bodies. While many studies of dust lofting state that the impact flux rate is orders of magnitude too low to account for the lunar horizon glow phenomenon and discount its contribution, it is imperative to re-examine these assumptions in light of new data on impact ejecta, particularly from the contributions from mesoscale (impactor size on the order of grain size) and macroscale (impactor > grain size) cratering. This is in large part due to a previous lack of data, for while past studies have established a canonical ejecta model for main-stage ejection of sand targets from vertical impacts, only recent studies have been able to begin quantitatively probing the intricacies of the ejection process outside this main-stage, vertical regime. In particular, it is the high-speed early-time ejecta that will reach

  8. Inoculation method could impact the outcome of microbiological experiments

    DEFF Research Database (Denmark)

    Kragh, Kasper Nørskov; Alhede, Maria; Rybtke, Morten

    2018-01-01

    characteristics with biofilms such as increased antibiotic tolerance. We have investigated how aggregates develop and what influences this development in LBC of Pseudomonas aeruginosa We focused on how the method of inoculation impacted aggregation by assessing aggregate frequency and size using confocal laser...... of biofilm aggregates in a LBC, with inoculation directly from a plate resulting in the most numerous and largest aggregates. These large aggregates had an overall impact on the cultures' subsequent tolerance towards tobramycin indicating that the inoculation method has a profound impact on antibiotic...... coli and Staphylococcus aureus also produce aggregates in LBC. Our results stress the importance of inoculation consistency throughout experiments and the substantial impact aggregate development in LBC has on the output of microbiological experiments.IMPORTANCE Liquid pure cultures are fundamental...

  9. Development and testing of a flexible ballistic neck protection

    NARCIS (Netherlands)

    Roebroeks, G.H.J.J.; Rensink, P.

    2016-01-01

    Sufficient ballistic protection of the neck area would significantly reduce the vulnerability of an infantry soldier. So far this protection is offered by extensions on the ballistic vest or combat helmet. However, the requirements for head agility and the various body to head positions combined

  10. A ballistic mission to fly by Comet Halley

    Science.gov (United States)

    Boain, R. J.; Hastrup, R. C.

    1980-01-01

    The paper describes the available options, ballistic trajectory opportunities, and a preliminary reference trajectory that were selected as a basis for spacecraft design studies and programmatic planning for a Halley ballistic intercept mission in 1986. The paper also presents trajectory, performance, and navigation data which support the preliminary selection.

  11. 76 FR 70165 - Ballistic-Resistant Body Armor Standard Workshop

    Science.gov (United States)

    2011-11-10

    ... of Justice Programs Ballistic-Resistant Body Armor Standard Workshop AGENCY: National Institute of..., Ballistic Resistance of Body Armor, and the discussion is directed toward manufacturers, certification... armor community will be summarized as part of the workshop notes. Contributors of comments will not be...

  12. An integrated approach towards future ballistic neck protection materials selection.

    Science.gov (United States)

    Breeze, John; Helliker, Mark; Carr, Debra J

    2013-05-01

    Ballistic protection for the neck has historically taken the form of collars attached to the ballistic vest (removable or fixed), but other approaches, including the development of prototypes incorporating ballistic material into the collar of an under body armour shirt, are now being investigated. Current neck collars incorporate the same ballistic protective fabrics as the soft armour of the remaining vest, reflecting how ballistic protective performance alone has historically been perceived as the most important property for neck protection. However, the neck has fundamental differences from the thorax in terms of anatomical vulnerability, flexibility and equipment integration, necessitating a separate solution from the thorax in terms of optimal materials selection. An integrated approach towards the selection of the most appropriate combination of materials to be used for each of the two potential designs of future neck protection has been developed. This approach requires evaluation of the properties of each potential material in addition to ballistic performance alone, including flexibility, mass, wear resistance and thermal burden. The aim of this article is to provide readers with an overview of this integrated approach towards ballistic materials selection and an update of its current progress in the development of future ballistic neck protection.

  13. Aerodynamic heating of ballistic missile including the effects of gravity

    Indian Academy of Sciences (India)

    http://www.ias.ac.in/article/fulltext/sadh/025/05/0463-0473. Keywords. Aerodynamic heating; ballistic missile; gravity; flat-earth. Abstract. The aerodynamic heating of a ballistic missile due to only convection is analysed taking into consideration the effects of gravity. The amount of heat transferred to the wetted area and to the ...

  14. Ballistic performance and microstructure of four armor ceramics

    NARCIS (Netherlands)

    Abadjieva, E.; Carton, E.P.

    2013-01-01

    The ballistic behavior of four different armor ceramic materials with thicknesses varying from 3 mm to 14 mm has been investigated. These are two types of alumina Al2O3 armor grades and two types of SiC armor grades produced by different armor ceramic producers. The ballistic study has been

  15. Field mapping of ballistic pressure pulse sources

    Directory of Open Access Journals (Sweden)

    Rad Abtin Jamshidi

    2015-09-01

    Full Text Available Ballistic pressure pulse sources are used since late 1990s for the extracorporeal treatment of chronic Enthesitis. Newly indications are found in trigger-point-therapy for the treatment of musculoskeletal disorders. In both applications excellent results without relevant side effects were found in clinical trials. The technical principle of pressure pulse source is based on the same techniques used in air guns. A projectile is accelerated by pressurized air and hits the applicator with high kinetic energy. By this a compression wave travels through the material and induces a fast (4..5μs, almost singular pressure pulse of 2..10 MPa, which is followed by an equally short rarefaction phase of about the same amplitude. It is assumed that the pressure pulse accounts for the biomedical effects of the device. The slower inertial motion of the waveguide is damped by elastic stoppers, but still can be measured several micro seconds after the initial pressure pulse. In order to characterize the pressure pulse devices, field mapping is performed on several radial pressure pulse sources using the fiber optic hydrophone and a polyvinylidenfluorid (PVDF piezoelectric hydrophone. It could be shown that the current standard (IEC 61846 is not appropriate for characterization of ballistic pressure pulse sources.

  16. Advanced geometries for ballistic neutron guides

    International Nuclear Information System (INIS)

    Schanzer, Christian; Boeni, Peter; Filges, Uwe; Hils, Thomas

    2004-01-01

    Sophisticated neutron guide systems take advantage of supermirrors being used to increase the neutron flux. However, the finite reflectivity of supermirrors becomes a major loss mechanism when many reflections occur, e.g. in long neutron guides and for long wavelengths. In order to reduce the number of reflections, ballistic neutron guides have been proposed. Usually linear tapered sections are used to enlarge the cross-section and finally, focus the beam to the sample. The disadvantages of linear tapering are (i) an inhomogeneous phase space at the sample position and (ii) a decreasing flux with increasing distance from the exit of the guide. We investigate the properties of parabolic and elliptic tapering for ballistic neutron guides, using the Monte Carlo program McStas with a new guide component dedicated for such geometries. We show that the maximum flux can indeed be shifted away from the exit of the guide. In addition we explore the possibilities of parabolic and elliptic geometries to create point like sources for dedicated experimental demands

  17. Ballistic resistant article, semi-finished product for and method of making a shell for a ballistic resistant article

    NARCIS (Netherlands)

    Harings, Jules; Janse, Gerardus

    2013-01-01

    The invention relates to a ballistic resistant article, such as a helmet (1), comprising a double curved shell (2) in turn comprising a stack (5) of layers (6) of an oriented anti-ballistic material, the layers (6) comprising one or more plies and having a plurality of cuts (7), the ends of which

  18. The Impact of Translators' Academic Experience on Their Translation Quality

    Science.gov (United States)

    Varzande, Mohsen; Jadidi, Esmaeil

    2015-01-01

    Translators differ from each other in many ways in terms of their knowledge and professional conditions that may directly influence their translation. The present study aimed at investigating the impact of translators' academic experience on their translation quality. Following a "causal-comparative study", a sample of 100 male and…

  19. Ballistic performance of a Kevlar-29 woven fibre composite under varied temperatures

    Science.gov (United States)

    Soykasap, O.; Colakoglu, M.

    2010-05-01

    Armours are usually manufactured from polymer matrix composites and used for both military and non-military purposes in different seasons, climates, and regions. The mechanical properties of the composites depend on temperature, which also affects their ballistic characteristics. The armour is used to absorb the kinetic energy of a projectile without any major injury to a person. Therefore, besides a high strength and lightness, a high damping capacity is required to absorb the impact energy transferred by the projectile. The ballistic properties of a Kevlar 29/polyvinyl butyral composite are investigated under varied temperatures in this study. The elastic modulus of the composite is determined from the natural frequency of composite specimens at different temperatures by using a damping monitoring method. Then, the backside deformation of composite plates is analysed experimentally and numerically employing the finite-element program Abaqus. The experimental and numeric results obtained are in good agreement.

  20. The relationship between mechanical properties and ballistic penetration depth in a viscoelastic gel.

    Science.gov (United States)

    Mrozek, Randy A; Leighliter, Brad; Gold, Christopher S; Beringer, Ian R; Yu, Jian H; VanLandingham, Mark R; Moy, Paul; Foster, Mark H; Lenhart, Joseph L

    2015-04-01

    The fundamental material response of a viscoelastic material when impacted by a ballistic projectile has important implication for the defense, law enforcement, and medical communities particularly for the evaluation of protective systems. In this paper, we systematically vary the modulus and toughness of a synthetic polymer gel to determine their respective influence on the velocity-dependent penetration of a spherical projectile. The polymer gels were characterized using tensile, compression, and rheological testing taking special care to address the unique challenges associated with obtaining high fidelity mechanical data on highly conformal materials. The depth of penetration data was accurately described using the elastic Froude number for viscoelastic gels ranging in Young's modulus from ~60 to 630 kPa. The minimum velocity of penetration was determined to scale with the gel toughness divided by the gel modulus, a qualitative estimate for the zone of deformation size scale upon impact. We anticipate that this work will provide insight into the critical material factors that control ballistic penetration behavior in soft materials and aid in the design and development of new ballistic testing media. Published by Elsevier Ltd.

  1. Ballistic and Diffusive Thermal Conductivity of Graphene

    Science.gov (United States)

    Saito, Riichiro; Masashi, Mizuno; Dresselhaus, Mildred S.

    2018-02-01

    This paper is a contribution to the Physical Review Applied collection in memory of Mildred S. Dresselhaus. Phonon-related thermal conductivity of graphene is calculated as a function of the temperature and sample size of graphene in which the crossover of ballistic and diffusive thermal conductivity occurs at around 100 K. The diffusive thermal conductivity of graphene is evaluated by calculating the phonon mean free path for each phonon mode in which the anharmonicity of a phonon and the phonon scattering by a 13C isotope are taken into account. We show that phonon-phonon scattering of out-of-plane acoustic phonon by the anharmonic potential is essential for the largest thermal conductivity. Using the calculated results, we can design the optimum sample size, which gives the largest thermal conductivity at a given temperature for applying thermal conducting devices.

  2. Ballistic thermoelectric transport in a Luttinger liquid

    International Nuclear Information System (INIS)

    Ivanov, Y V

    2010-01-01

    The Seebeck and Peltier coefficients of a homogeneous Luttinger liquid are calculated in the ballistic regime. Nonlinearity of the electron spectrum is taken into account. It is shown that, in the framework of the defined approximations, the thermoelectric power of a Luttinger liquid is equal to zero, in agreement with the exponentially small thermopower of a one-dimensional degenerate Fermi gas. The Peltier coefficient is controlled by a nonequilibrium state of the system. It is finite and renormalized by the interaction in the case of a convective flow of a Luttinger liquid. The zero modes of bosonic excitations and the dispersion-induced contribution to the electric current operator are taken into account in calculations.

  3. Ballistic transport in gold [110] nanowire

    Science.gov (United States)

    Kurui, Yoshihiko; Oshima, Yoshifumi; Okamoto, Masakuni; Takayanagi, Kunio

    2009-03-01

    Conductance of gold nanowire elongated along the [110] direction (gold [110] nanowire) was measured during many breaking procedures, while simultaneously acquiring transmission electron microscope images. The conductance histogram exhibits a series of peaks whose conductance values increased nearly in steps of the conductance quantum, G0 =2e^2/h. However thick nanowires above 10G0 showed dequantization, where the increment was only 0.9G0. The structure for each peak was determined to be either an atomic sheet or a hexagonal prism. The number of conductance channels calculated for each atomic structure by first principles theory, coincided well with the peak index in the conductance histogram. The present study shows that the [110] nanowire behave as ballistic conductors, and a conductance peak appears whenever a conductance channel is opened.

  4. Ballistic Missile Defense: New Plans, Old Challenges

    Directory of Open Access Journals (Sweden)

    Elizabeth Zolotukhina

    2010-01-01

    Full Text Available On September 17, 2009—the 70th anniversary of the Soviet invasion of Poland in 1939 that marked the beginning of World War II—the Obama Administration announced its intention to shelve plans for the U.S. Ballistic Missile Defense (BMD that had been developed under former President George W. Bush. Pointing to a new intelligence assessment, President Obama argued that his predecessor's plan to deploy an X-band radar station outside of Prague, Czech Republic, and 10 two-stage interceptor missiles in Poland would not adequately protect America and its European allies from the Iranian threat and reiterated his opposition to utilizing unproven technology in any European BMD architecture.

  5. Ballistic energy transport in PEG oligomers

    Directory of Open Access Journals (Sweden)

    Kireev Victor V.

    2013-03-01

    Full Text Available Energy transport between the terminal groups of the azido-PEG-succinimide ester compounds with a number of repeating PEG units of 0, 4, 8, and 12 was studied using relaxation-assisted two-dimensional infrared spectroscopy. The through-bond energy transport time, evaluated as the waiting time at which the cross peak maximum is reached, Tmax, was found to be linearly dependent on the chain length for chain lengths up to 60 Å suggesting a ballistic energy transport regime. The through-bond energy transport speed is found to be ca. 500 m/s. The cross-peak amplitude at the maximum decays exponentially with the chain length with a characteristic decay distance of 15.7 ± 1 Å. Substantial mode delocalization across the PEG bridge is found, which can support the energy propagation as a wavepacket.

  6. Statistics of magnetoconductance in ballistic cavities

    International Nuclear Information System (INIS)

    Yang, X.; Ishio, H.; Burgdoerfer, J.

    1995-01-01

    The statistical properties of magnetoconductance in ballistic microcavities are investigated numerically. The distribution of conductance for chaotic cavities is found to follow the renormalized Porter-Thomas distribution suggested by random-matrix theory for the Gaussian ensemble while the conductance distribution of regular cavities in magnetic fields is nonuniversal and shifted towards the maximum value for a given number of open channels. The renormalized Porter-Thomas distribution implies a universal dependence of fluctuation amplitude on the mean conductance for chaotic cavities in the absence of time-reversal symmetry. The fluctuation amplitude for regular cavities is found to be larger than the saturation value of the fluctuation amplitude of chaotic cavities predicted by random-matrix theory. The change of the mean conductance as a function of the external magnetic field is consistent with semiclassical predictions

  7. 19 mm ballistic range: a potpourri of techniques and recipes

    International Nuclear Information System (INIS)

    Carpluk, G.T.

    1975-01-01

    The expansion of ballistic gun range facilities at LLL has introduced state-of-the-art diagnostic techniques to glovebox-enclosed ballistic guns systems. These enclosed ballistic ranges are designed for the study of one-dimensional shock phenomena in extremely toxic material such as plutonium. The extension of state-of-the-art phtographic and interferometric diagnostic systems to glovebox-enclosed gun systems introduces new design boundaries and performance criteria on optical and mechanical components. A technique for experimentally evaluating design proposals is illustrated, and several specific examples (such as, target alignment, collateral shrapnel damage, and soft recovery) are discussed

  8. Influence of the vacuum resin process, on the ballistic behaviour of lightweight armouring solutions

    Science.gov (United States)

    Lefebvre, M.; Boussu, F.; Coutellier, D.; Vallee, D.

    2012-08-01

    The armour of vehicles against conventional threats is mainly composed with steel or aluminium panels. Efficient heavy solutions exist, but the involved industries require new lightweight structures. Moreover, unconventional threats as IEDs (Improvised Explosive Devices) may cause severe damages on these structural and protective panel solutions. Thus, combination of aluminium or steel plates with textile composite structures used as a backing, leads to the mass reduction and better performance under delamination behaviour against these new threats. This paper is a part of a study dealing with the impact behaviour of three warp interlocks weaving structures under Fragment Simulating Projectile (FSP) impact. During this research, several parameters has being studied as the influence of the yarns insertions [1-4], the degradation of the yarns during the weaving process [5-7], and the influence of the resin rate on the ballistic behaviour. The resin rate inside composite materials is dependant on the final application. In ballistic protection, we need to control the resin rate in order to have a deformable structure in order to absorb the maximum of energy. However, with the warp interlocks weaving structure, the yarns insertions induce empty spaces between the yarns where the resin takes place without being evacuated. The resin rate inside the warp interlocks structures is in the most of cases less than 50%, which lead to have brittle and hard material during the impact. Contrary to interlocks structures, the existing protection based on prepreg structure have a high fibres ratio around 88% of weight. That leads to have the best ballistic properties during the impact and good deformability of the structure. The aim of this paper is to evaluate the influence of the resin rate on the ballistic results of the composites materials. For that, we have chosen two kinds of warp interlocks fabrics which were infused with epoxy resin following two processes. The first is a

  9. Influence of the vacuum resin process, on the ballistic behaviour of lightweight armouring solutions

    Directory of Open Access Journals (Sweden)

    Coutellier D.

    2012-08-01

    Full Text Available The armour of vehicles against conventional threats is mainly composed with steel or aluminium panels. Efficient heavy solutions exist, but the involved industries require new lightweight structures. Moreover, unconventional threats as IEDs (Improvised Explosive Devices may cause severe damages on these structural and protective panel solutions. Thus, combination of aluminium or steel plates with textile composite structures used as a backing, leads to the mass reduction and better performance under delamination behaviour against these new threats. This paper is a part of a study dealing with the impact behaviour of three warp interlocks weaving structures under Fragment Simulating Projectile (FSP impact. During this research, several parameters has being studied as the influence of the yarns insertions [1–4], the degradation of the yarns during the weaving process [5–7], and the influence of the resin rate on the ballistic behaviour. The resin rate inside composite materials is dependant on the final application. In ballistic protection, we need to control the resin rate in order to have a deformable structure in order to absorb the maximum of energy. However, with the warp interlocks weaving structure, the yarns insertions induce empty spaces between the yarns where the resin takes place without being evacuated. The resin rate inside the warp interlocks structures is in the most of cases less than 50%, which lead to have brittle and hard material during the impact. Contrary to interlocks structures, the existing protection based on prepreg structure have a high fibres ratio around 88% of weight. That leads to have the best ballistic properties during the impact and good deformability of the structure. The aim of this paper is to evaluate the influence of the resin rate on the ballistic results of the composites materials. For that, we have chosen two kinds of warp interlocks fabrics which were infused with epoxy resin following two

  10. LCROSS Impact Conditions and Ejecta Evolution: Insight from Experiments

    Science.gov (United States)

    Hermalyn, B.; Schultz, P. H.; Colaprete, A.

    2009-12-01

    The ejecta distribution resulting from an impact event reflects the impact conditions and target material properties. The Lunar CRater Observation and Sensing Satellite (LCROSS) mission will provide a rare look at subsurface materials. The LCROSS impact will excavate regolith from a permanently shadowed crater on the south pole of the moon. The impactor, named the Earth-Departure-Upper-Stage (EDUS), will impact the surface at ~2.5km/s at an angle of greater than 80° from horizontal. The trailing Shepherding Spacecraft (SSc) will record the impact and take measurements of the ejecta in coordination with a comprehensive earth-based observational campaign. Prior studies have explored the predicted ejecta mass/velocity distribution and general ejecta dynamics through computational modeling (Korycansky, et al 2009) and scaling laws(Schultz, 2006, Heldmann et al 2007). At very early times, however, these models and scaling laws break down. It is this high-speed component of the ejected material that will reach the sunlight horizon first and will be recorded by the SSc. Thus to interpret the initial conditions of the impact from the LCROSS ejecta plume, the early-time ejecta distribution must be understood. A suite of impact experiments (performed at the NASA Ames Vertical Gun Range, or AVGR) were designed to interpret LCROSS conditions. These experiments reveal that early in the cratering process, when the projectile is still coupling its energy and momentum to the target surface, ejection velocity is higher than predicted by dimensional scaling laws (Housen, et al 1983). Moreover, the ejection angles of this early-time component are initially lower than predicted, and sweep upward tens of degrees to reach nominal ejection angles (~45° for impacts into sand). Low-density projectiles (such as the EDUS) yield even lower ejection angles throughout much of crater growth, thereby indicating a shallower depth of coupling. An estimate of mass above a given height calculated

  11. Impact of childhood experience of famine on late life health.

    Science.gov (United States)

    Woo, J; Leung, J C S; Wong, S Y S

    2010-02-01

    This study examines whether experience of famine during late childhood affect late life health. Cross sectional cohort survey carried out from 2001-2004. Community in Hong Kong. 1,906 men and 1,826 women aged >or= 65 years living in the community. We examined the impact of experience of famine during late childhood, defined as caloric restriction for at least one year, on body mass index, body composition using DEXA, grip strength, walking speed and stride length, blood pressure, and ankle-brachial index,using logistic regression adjusting for various co-variates (age, lifestyle, socioeconomic factors). Participants who had been exposed to a period of undernutrition in late childhood were shorter, had higher body mass index (BMI) and appendicular lean mass/height2, higher prevalence of recurrent falls, higher prevalence of myocardial infarct, arthritis and back pain. Late childhood undernutrition has some adverse impact on late life health and functional outcomes.

  12. Formation of shatter cones in MEMIN impact experiments

    Science.gov (United States)

    Wilk, J.; Kenkmann, T.

    2016-08-01

    Shatter cones are the only macroscopic feature considered as evidence for shock metamorphism. Their presence is diagnostic for the discovery and verification of impact structures. The occurrence of shatter cones is heterogeneous throughout the crater record and their geometry can diverge from the typical cone shape. The precise formation mechanism of shatter cones is still not resolved. In this study, we aim at better constraining the boundary conditions of shatter cone formation in impact experiments and test a novel approach to qualitatively and quantitatively describe shatter cone geometries by white light interferometry. We recovered several ejected fragments from MEMIN cratering experiments that show slightly curved, striated surfaces and conical geometries with apices of 36°-52°. These fragments fulfilling the morphological criteria of shatter cones were found in experiments with 20-80 cm sized target cubes of sandstone, quartzite and limestone, but not in highly porous tuff. Targets were impacted by aluminum, steel, and iron meteorite projectiles at velocities of 4.6-7.8 km s-1. The projectile sizes ranged from 2.5-12 mm in diameter and produced experimental peak pressures of up to 86 GPa. In experiments with lower impact velocities shatter cones could not be found. A thorough morphometric analysis of the experimentally generated shatter cones was made with 3D white light interferometry scans at micrometer accuracy. SEM analysis of the surfaces of recovered fragments showed vesicular melt films alternating with smoothly polished surfaces. We hypothesize that the vesicular melt films predominantly form at strain releasing steps and suggest that shatter cones are probably mixed mode fractures.

  13. Institute for Non-Lethal Defense Technologies Report: Ballistic Gelatin

    National Research Council Canada - National Science Library

    Nicholas, N. C; Welsch, J. R

    2004-01-01

    Ballistic gelatin is designed to simulate living soft tissue. It is the standard for evaluating the effectiveness of firearms against humans because of its convenience and acceptability over animal or cadaver testing...

  14. Designing an Innovative Composite Armor System for Affordable Ballistic Protection

    National Research Council Canada - National Science Library

    Ma, Zheng-Dong; Wang, Hui; Cui, Yushun; Rose, Douglas; Socks, Adria; Ostberg, Donald

    2006-01-01

    .... This paper focuses on the frontal armor plate and back plate design problems with demonstration examples, including both results of the virtual prototyping and ballistic testing for proof-of-concept...

  15. North Korean Ballistic Missile Threat to the United States

    National Research Council Canada - National Science Library

    Hildreth, Steven A

    2007-01-01

    ... so. The Administration will ask the 110th Congress to fund a National Missile Defense (NMD) site in Europe, which some analysts argue is needed because of the threat of North Korean ballistic missiles to Europe...

  16. Current neutralization in ballistic transport of light ion beams

    International Nuclear Information System (INIS)

    Hubbard, R.F.; Slinker, S.P.; Lampe, M.; Joyce, G.; Ottinger, P.

    1992-01-01

    Intense light ion beams are being considered as drivers to ignite fusion targets in the Laboratory Microfusion Facility (LMF). Ballistic transport of these beams from the diode to the target is possible only if the beam current is almost completely neutralized by plasma currents. This paper summarizes related work on relativistic electron beam and heavy ion beam propagation and describes a simple simulation model (DYNAPROP) which has been modified to treat light ion beam propagation. DYNAPROP uses an envelope equation to treat beam dynamics and uses rate equations to describe plasma and conductivity generation. The model has been applied both to the high current, 30 MeV Li +3 beams for LMF as well as low current, 1.2 MeV proton beams which are currently being studied on GAMBLE B at the Naval Research Laboratory. The predicted ratio of net currents to beam current is ∼0.1--0.2 for the GAMBLE experiment and ∼0.01 for LMF. The implications of these results for LMF and the GAMBLE experiments art discussed in some detail. The simple resistive model in DYNAPROP has well-known limitations in the 1 torr regime which arise primarily from the neglect of plasma electron transport. Alternative methods for treating the plasma response are discussed

  17. Balancing ballistic protection against physiological strain: evidence from laboratory and field trials.

    Science.gov (United States)

    Taylor, Nigel A S; Burdon, Catriona A; van den Heuvel, Anne M J; Fogarty, Alison L; Notley, Sean R; Hunt, Andrew P; Billing, Daniel C; Drain, Jace R; Silk, Aaron J; Patterson, Mark J; Peoples, Gregory E

    2016-02-01

    This project was based on the premise that decisions concerning the ballistic protection provided to defence personnel should derive from an evaluation of the balance between protection level and its impact on physiological function, mobility, and operational capability. Civilians and soldiers participated in laboratory- and field-based studies in which ensembles providing five levels of ballistic protection were evaluated, each with progressive increases in protection, mass (3.4-11.0 kg), and surface-area coverage (0.25-0.52 m(2)). Physiological trials were conducted on volunteers (N = 8) in a laboratory, under hot-dry conditions simulating an urban patrol: walking at 4 km·h(-1) (90 min) and 6 km·h(-1) (30 min or to fatigue). Field-based trials were used to evaluate tactical battlefield movements (mobility) of soldiers (N = 31) under tropical conditions, and across functional tests of power, speed, agility, endurance, and balance. Finally, trials were conducted at a jungle training centre, with soldiers (N = 32) patrolling under tropical conditions (averaging 5 h). In the laboratory, work tolerance was reduced as protection increased, with deep-body temperature climbing relentlessly. However, the protective ensembles could be grouped into two equally stressful categories, each providing a different level of ballistic protection. This outcome was supported during the mobility trials, with the greatest performance decrement evident during fire and movement simulations, as the ensemble mass was increased (-2.12%·kg(-1)). The jungle patrol trials similarly supported this outcome. Therefore, although ballistic protection does increase physiological strain, this research has provided a basis on which to determine how that strain can be balanced against the mission-specific level of required personal protection.

  18. Do global change experiments overestimate impacts on terrestrial ecosystems?

    DEFF Research Database (Denmark)

    Leuzinger, Sebastian; Luo, Yiqi; Beier, Claus

    2011-01-01

    In recent decades, many climate manipulation experiments have investigated biosphere responses to global change. These experiments typically examined effects of elevated atmospheric CO2, warming or drought (driver variables) on ecosystem processes such as the carbon and water cycle (response...... of the responses to decline with higher-order interactions, longer time periods and larger spatial scales. This means that on average, both positive and negative global change impacts on the biosphere might be dampened more than previously assumed....... variables). Because experiments are inevitably constrained in the number of driver variables tested simultaneously, as well as in time and space, a key question is how results are scaled up to predict net ecosystem responses. In this review, we argue that there might be a general trend for the magnitude...

  19. The Modeling and Application of Small Arms Wound Ballistics

    Science.gov (United States)

    1991-08-01

    Components." The Journal of Traurma, vol. 25, pp. 522-529, 1985. 3. Clare, V., W. Ashman, P. Broome, J. Jameson, J. Lewis, J. Merkler, A. Mickiewicz , W...Proving Ground, MD, 1962. 28. Olivier, A., J. Merkler, B. Brown, and A. Mickiewicz . ’Wound Ballistics of the 15.2 Grain Steel Flechette." CRDLR 3132...NWerkler, A. Mickiewicz , W. Sacco, L. Sturdivan, D. Lamb, and F. Sylva,)us. "The ARRADCOM Computer Man - An Automated Approach To Wound Ballistics

  20. Ballistic Heat Conduction and Mass Disorder in One Dimension

    OpenAIRE

    Ong, Zhun-Yong; Zhang, Gang

    2014-01-01

    It is well-known that in the disordered harmonic chain, heat conduction is subballistic and the thermal conductivity ($\\kappa$) scales asymptotically as $\\lim_{L\\rightarrow\\infty}\\kappa\\propto L^{0.5}$ where $L$ is the chain length. However, using the nonequilibrium Green's function (NEGF) method and analytical modeling, we show that there exists a critical crossover length scale ($L_{C}$) below which ballistic heat conduction ($\\kappa\\propto L$) can coexist with mass disorder. This ballistic...

  1. Impact of detector simulation in particle physics collider experiments

    Science.gov (United States)

    Daniel Elvira, V.

    2017-06-01

    Through the last three decades, accurate simulation of the interactions of particles with matter and modeling of detector geometries has proven to be of critical importance to the success of the international high-energy physics (HEP) experimental programs. For example, the detailed detector modeling and accurate physics of the Geant4-based simulation software of the CMS and ATLAS particle physics experiments at the European Center of Nuclear Research (CERN) Large Hadron Collider (LHC) was a determinant factor for these collaborations to deliver physics results of outstanding quality faster than any hadron collider experiment ever before. This review article highlights the impact of detector simulation on particle physics collider experiments. It presents numerous examples of the use of simulation, from detector design and optimization, through software and computing development and testing, to cases where the use of simulation samples made a difference in the precision of the physics results and publication turnaround, from data-taking to submission. It also presents estimates of the cost and economic impact of simulation in the CMS experiment. Future experiments will collect orders of magnitude more data with increasingly complex detectors, taxing heavily the performance of simulation and reconstruction software. Consequently, exploring solutions to speed up simulation and reconstruction software to satisfy the growing demand of computing resources in a time of flat budgets is a matter that deserves immediate attention. The article ends with a short discussion on the potential solutions that are being considered, based on leveraging core count growth in multicore machines, using new generation coprocessors, and re-engineering HEP code for concurrency and parallel computing.

  2. Stigma experiences in bipolar patients: the impact upon functioning.

    Science.gov (United States)

    Thomé, E S; Dargél, A A; Migliavacca, F M; Potter, W A; Jappur, D M C; Kapczinski, F; Ceresér, K M

    2012-10-01

    The aim of this study was to investigate the impact of self-rated stigma and functioning in patients with bipolar disorder in South Brazil. This is a cross-sectional study. Sixty participants with bipolar disorder were recruited from an outpatient Bipolar Disorder Program. Experiences with and impact of perceived stigma were evaluated using the Inventory of Stigmatizing Experiences. Functional impairment was assessed with the Functioning Assessment Short Test (FAST). Higher scores of self-perceived stigma were correlated with higher FAST scores, indicating more disability. After linear correlation analysis, current depressive symptoms, age at onset of treatment, age at diagnosis and functioning were correlated with self-perceived stigma. The study demonstrated a correlation between stigma and poor functioning in bipolar disorder. Perceived stigma is really important to individuals with bipolar disorder, both to how they experience their illness and to its results on functioning. Potential consequences of such results for mental health care professionals are discussed. Differential clinical features, sociocultural factors and the sample size limit the generalization of the present findings. © 2011 Blackwell Publishing.

  3. Clothing increases the risk of indirect ballistic fractures

    Science.gov (United States)

    2013-01-01

    Background Current literature has shown the mechanism of how indirect fractures occur but has not determined what factors increase the risks of such fractures. The objective of this study is thus to determine the effect of clothing and soft tissue thickness on the risk of indirect fracture formation. Methods Twenty-five fresh red deer femora embedded in ballistic gelatine were shot with varying distances off their medial cortex with a 5.56 × 45 mm North Atlantic Treaty Organization (NATO) bullet while being filmed with a slow-motion video. We compared the effect of two different gelatine depths and the effect of denim cloth laid onto the impact surface of the moulds. Results Bullet passage in thinner moulds failed to cause fracture because the bullet exited the mould before a large expanding temporary cavity was produced. Clothing dramatically altered the size and depth of the expanding cavity, as well as increased lateral pressures, resulting in more severe fractures with greater bullet distances from the bone that can cause fracture. Conclusions Clothing increases the risk of indirect fracture and results in larger, more superficial temporary cavities, with greater lateral pressures than are seen in unclothed specimens, resulting in more comminuted fractures. Greater tissue depth affords the 5.56 × 45 mm NATO a chance to yaw and thus develop an enlarging temporary cavity that is sufficient to cause fracture. PMID:24267379

  4. Photodegradation in ballistic laminates: Spectroscopy and lifetime extension

    Energy Technology Data Exchange (ETDEWEB)

    Renschler, C.L.; Stallard, B.R.; White, C.A.; Garcia, M.J.; Morse, H.E. [Sandia National Labs., Albuquerque, NM (United States). Properties of Organic Materials Dept.

    1996-06-01

    Several years ago, the Materials and Process Sciences Center (Org. 1800) was asked by Dept. 9613 to study the materials aging issues which had led to the loss of ballistic protection by Armored Tractor (AT) windshields and windows. The authors speculated that this loss of impact strength was due to photodegradation of the polycarbonate (PC) inboard ply. They developed a spectroscopic method to identify changes in the outboard surface of the PC, and showed that the changes in the surface which occurred upon natural aging in the field could be reproduced by exposing the laminates to a simulated solar flux. Based on these results, they recommended changes in the adhesive interlayers to filter out the ultraviolet (UV) light causing the aging problem. Working with the laminate vendor, PPG, they re-designed the laminates to implement these changes and block essentially all UV light from the inboard ply. The most recent phase of this work involved accelerated solar aging of laminates made with the new design to verify that photoaging effects have been blocked by the new materials. They report here the results of that study, and recommended follow-on work.

  5. The NOL ballistic piston compressor 2: Operation up to 5,000 ATM

    Science.gov (United States)

    Hammond, G. L.; Lalos, G. T.

    1971-01-01

    Experiments are described which demonstrated the feasibility of rapidly compressing inert gases in a ballistic piston compressor to simultaneously high temperatures and densities previously unobtainable in the laboratory. With argon, temperatures of the order of 6000 K and accompanying densities of the order of 100 Amagats have been obtained; and with nitrogen, temperatures and densities of 3000 K and 400 Amagats have been approached. Details of the design, assembly, instrumentation, and operating procedures are presented, and the results of mechanical and thermal performance tests up to 5000 atmospheres pressure are described. Emphasis is placed on experiments which demonstrated the usefulness of this apparatus for spectral line broadening studies.

  6. Physics of Regolith Impacts in Microgravity Experiment (PRIME)

    Science.gov (United States)

    Motil, Brian (Technical Monitor); Colwell, Joshua; Sture, S.

    2003-01-01

    Collisions between planetary ring particles and in some protoplanetary disk environments occur at low impact velocities (v less than 1 m/s) . In some regions of Saturn s rings, for example, the typical collision velocity inferred from observations by the Voyager spacecraft and dynamical modeling is a fraction of a centimeter per second. Although no direct observations of an individual ring particle exist, the abundance of dust in planetary rings and protoplanetary disks suggests that larger ring and disk particles are coated with a layer of smaller particles and dust - the "regolith". Because the ring particles and proto-planetesimals are small (cm to m-sized), the regolith is only weakly bound to the surface by gravity. Similarly, secondary impacts on asteroids by large blocks of ejecta from high velocity cratering events result in low velocity impacts into the asteroid regolith, which is also weakly bound by the asteroid s gravity. At the current epoch and throughout their history, low velocity collisions have played an important role in sculpting planetary systems. In a one-Earth-gravity environment, it is not possible to experimentally determine the behavior of impact eject from such low velocity collisions. Impacts typically occur at speeds exceeding the mutual escape velocity of the two bodies. Thus, impacts at speeds on the order of 10 m/sec or less involve objects that are tens of meters across, or smaller. This research program is an experimental study of such low velocity collisions in a microgravity environment. The experimental work builds on the Collisions Into Dust Experiment (COLLIDE), which has flown twice on the space shuttle. The PRIME experimental apparatus is a new apparatus designed specifically for the environment provided on the NASA KC- 135 reduced gravity aircraft.

  7. Impact of Experience Corps(®) participation on school climate.

    Science.gov (United States)

    Parisi, Jeanine M; Ramsey, Christine M; Carlson, Michelle C; Xue, Qian-Li; Huang, Jin; Romani, William A; McGill, Sylvia; Seeman, Teresa E; Tanner, Elizabeth K; Barron, Jeremy; Tan, Erwin J; Gruenewald, Tara L; Diibor, Ike; Fried, Linda P; Rebok, George W

    2015-07-01

    We examined the impact of the Experience Corps(®) (EC) program on school climate within Baltimore City public elementary schools. In this program, teams of older adult volunteers were placed in high intensity (>15 h per week), meaningful roles in public elementary schools, to improve the educational outcomes of children as well as the health and well-being of volunteers. During the first year of EC participation, school climate was perceived more favorably among staff and students in EC schools as compared to those in comparison schools. However, with a few notable exceptions, perceived school climate did not differ for staff or students in intervention and comparison schools during the second year of exposure to the EC program. These findings suggest that perceptions of school climate may be altered by introducing a new program into elementary schools; however, research examining how perceptions of school climate are impacted over a longer period is warranted.

  8. Impact of Experience Corps® Participation on School Climate

    Science.gov (United States)

    Parisi, Jeanine M.; Ramsey, Christine M.; Carlson, Michelle C.; Xue, Qian-Li; Huang, Jin; Romani, William A.; McGill, Sylvia; Seeman, Teresa E.; Tanner, Elizabeth K.; Barron, Jeremy; Tan, Erwin; Gruenewald, Tara L.; Diibor, Ike; Fried, Linda P.; Rebok, George W.

    2015-01-01

    We examined the impact of the Experience Corps® (EC) program on school climate within Baltimore City public elementary schools. In this program, teams of older adult volunteers were placed in high intensity (>15 hours per week), meaningful roles in public elementary schools, to improve the educational outcomes of children as well as the health and well-being of volunteers. During the first year of EC participation, school climate was perceived more favorably among staff and students in EC schools as compared to those in comparison schools. However, with a few notable exceptions, perceived school climate did not differ for staff or students in intervention and comparison schools during the second year of exposure to the EC program. These findings suggest that perceptions of school climate may be altered by introducing a new program into elementary schools; however, research examining how perceptions of school climate are impacted over a longer period is warranted. PMID:25708453

  9. Memory for Lectures: How Lecture Format Impacts the Learning Experience

    Science.gov (United States)

    Varao-Sousa, Trish L.; Kingstone, Alan

    2015-01-01

    The present study investigated what impact the presentation style of a classroom lecture has on memory, mind wandering, and the subjective factors of interest and motivation. We examined if having a professor lecturing live versus on video alters the learning experience of the students in the classroom. During the lectures, students were asked to report mind wandering and later complete a memory test. The lecture format was manipulated such that all the students received two lectures, one live and one a pre-recorded video. Results indicate that lecture format affected memory performance but not mind wandering, with enhanced memory in the live lectures. Additionally, students reported greater interest and motivation in the live lectures. Given that a single change to the classroom environment, professor presence, impacted memory performance, as well as motivation and interest, the present results have several key implications for technology-based integrations into higher education classrooms. PMID:26561235

  10. Heat Coulomb blockade of one ballistic channel

    Science.gov (United States)

    Sivre, E.; Anthore, A.; Parmentier, F. D.; Cavanna, A.; Gennser, U.; Ouerghi, A.; Jin, Y.; Pierre, F.

    2018-02-01

    Quantum mechanics and Coulomb interaction dictate the behaviour of small circuits. The thermal implications cover fundamental topics from quantum control of heat to quantum thermodynamics, with prospects of novel thermal machines and an ineluctably growing influence on nanocircuit engineering. Experimentally, the rare observations thus far include the universal thermal conductance quantum and heat interferometry. However, evidence for many-body thermal effects paving the way to markedly different heat and electrical behaviours in quantum circuits remains wanting. Here we report on the observation of the Coulomb blockade of electronic heat flow from a small metallic circuit node, beyond the widespread Wiedemann-Franz law paradigm. We demonstrate this thermal many-body phenomenon for perfect (ballistic) conduction channels to the node, where it amounts to the universal suppression of precisely one quantum of conductance for the transport of heat, but none for electricity. The inter-channel correlations that give rise to such selective heat current reduction emerge from local charge conservation, in the floating node over the full thermal frequency range (<~temperature × kB/h). This observation establishes the different nature of the quantum laws for thermal transport in nanocircuits.

  11. Ballistic Josephson junctions based on CVD graphene

    Science.gov (United States)

    Li, Tianyi; Gallop, John; Hao, Ling; Romans, Edward

    2018-04-01

    Josephson junctions with graphene as the weak link between superconductors have been intensely studied in recent years, with respect to both fundamental physics and potential applications. However, most of the previous work was based on mechanically exfoliated graphene, which is not compatible with wafer-scale production. To overcome this limitation, we have used graphene grown by chemical vapour deposition (CVD) as the weak link of Josephson junctions. We demonstrate that very short, wide CVD-graphene-based Josephson junctions with Nb electrodes can work without any undesirable hysteresis in their electrical characteristics from 1.5 K down to a base temperature of 320 mK, and their gate-tuneable critical current shows an ideal Fraunhofer-like interference pattern in a perpendicular magnetic field. Furthermore, for our shortest junctions (50 nm in length), we find that the normal state resistance oscillates with the gate voltage, consistent with the junctions being in the ballistic regime, a feature not previously observed in CVD-graphene-based Josephson junctions.

  12. China and ballistic missile defense: 1955 to 2002 and beyond

    Energy Technology Data Exchange (ETDEWEB)

    Brad, Roberts

    2004-07-01

    China's opposition to U.S. ballistic missile defense was forcefully articulated officially and unofficially between 1991 and 2001. Vociferous opposition gave way to near silence following U.S. ABM Treaty withdrawal, raising a question about precisely whether and how China will respond to future U.S. deployments in both the political and military-operational realms. To gauge likely future responses, it is useful to put the experience of the 1991-2001 period into historical context. China's attitudes toward BMD have passed through a series of distinct phases since the beginning of the nuclear era, as China has been concerned alternately with the problems of strategic defense by both the Soviet Union and United States (and others) around its periphery. Throughout this era it has also pursued its own strategic defense capabilities. There are important elements of continuity in China's attitudes concerns about the viability of its own force and about strategic stability. These suggest the likelihood of significant responses to U.S. BMD even in the absence of sharp rhetoric. (author)

  13. China and ballistic missile defense: 1955 to 2002 and beyond

    International Nuclear Information System (INIS)

    Brad, Roberts

    2004-01-01

    China's opposition to U.S. ballistic missile defense was forcefully articulated officially and unofficially between 1991 and 2001. Vociferous opposition gave way to near silence following U.S. ABM Treaty withdrawal, raising a question about precisely whether and how China will respond to future U.S. deployments in both the political and military-operational realms. To gauge likely future responses, it is useful to put the experience of the 1991-2001 period into historical context. China's attitudes toward BMD have passed through a series of distinct phases since the beginning of the nuclear era, as China has been concerned alternately with the problems of strategic defense by both the Soviet Union and United States (and others) around its periphery. Throughout this era it has also pursued its own strategic defense capabilities. There are important elements of continuity in China's attitudes concerns about the viability of its own force and about strategic stability. These suggest the likelihood of significant responses to U.S. BMD even in the absence of sharp rhetoric. (author)

  14. The Impact of Nature Experience on Willingness to Support Conservation

    Science.gov (United States)

    Zaradic, Patricia A.; Pergams, Oliver R. W.; Kareiva, Peter

    2009-01-01

    We hypothesized that willingness to financially support conservation depends on one's experience with nature. In order to test this hypothesis, we used a novel time-lagged correlation analysis to look at times series data concerning nature participation, and evaluate its relationship with future conservation support (measured as contributions to conservation NGOs). Our results suggest that the type and timing of nature experience may determine future conservation investment. Time spent hiking or backpacking is correlated with increased conservation contributions 11–12 years later. On the other hand, contributions are negatively correlated with past time spent on activities such as public lands visitation or fishing. Our results suggest that each hiker or backpacker translates to $200–$300 annually in future NGO contributions. We project that the recent decline in popularity of hiking and backpacking will negatively impact conservation NGO contributions from approximately 2010–2011 through at least 2018. PMID:19809511

  15. The method of neutron imaging as a tool for the study of the dynamics of water movement in wet aramid-based ballistic body armour panels

    Science.gov (United States)

    Reifler, Felix A.; Lehmann, Eberhard H.; Frei, Gabriel; May, Hans; Rossi, René

    2006-07-01

    A new non-destructive method based on neutron imaging (neutron radiography) to determine the exact water content in aramid-based soft body armour panels is presented. While investigating the ballistic resistance of aramid-based body armour panels under a wet condition, it is important to precisely determine their water content and its chronological development. Using the presented method, the influence of water amount and location on impact testing as well as its time dependence was shown. In the ballistic panels used, spreading of water strongly depended on the kind of quilting. Very fast water migration could be observed when the panels were held vertically. Some first results regarding the water distribution in wet panels immediately after the impact are presented. On the basis of the presented results, requirements for a standard for testing the performance of ballistic panels in the wet state are deduced.

  16. Ballistic analysis during multiscale explosive eruption at Vesuvius and hazard implications

    Science.gov (United States)

    De Novellis, Vincenzo

    2016-04-01

    Ballistic Projectiles (BP) are rock-basement or magma fragments of variable size and density that are ejected from vents during explosive eruptions and follow almost parabolic trajectories that are influenced by gravity and drag forces before they reach their impact point on the surface. During the past century, numerous observers have described the violent ejection of large blocks and bombs from volcanoes during volcanic explosions. Starting from '40 years of last century, several authors developed a mathematical expression relating initial velocity and trajectory angle of ejected blocks to the range, taking into account air drag and assuming a constant drag coefficient; but only in the last 30 years was developed the first mathematical algorithm for ballistic trajectories in the volcanological literature that considered variations in drag coefficient with Reynolds number. Finally, with 21st century computer power, ballistic computation should be available to anyone as a back-of-the-envelope indicator of explosive power by a user-friendly computer program. At Mt. Vesuvius a series of explosion events accompanied eruptive mechanism stages during its history. In particular the explosive eruptive events at Vesuvius was affected by 3 types of energy activity: i) a normal strombolian activity that consists of rhythmic, mild to moderate explosions lasting a few seconds that eject scoriaceous lapilli and bombs, ash and lithic blocks; ii) a vulcanian or violent explosions characterized by short-lived events involving more than one vent, defined as strombolian paroxysms; iii) from sublinian to plinian activity, that have been the most powerful events observed at Mt. Vesuvius; on the other hand plinian was indicated as the energetic term to define the most famous eruption of 79 AD. In this study, an eruptive model appropriate for exanimated eruptions, is used to estimate initial conditions (ejection height, take-off angle, velocity) for BP, assuming a broad range of gas

  17. Balance in scientific impact assessment: the EGU Awards Committe experience

    Science.gov (United States)

    Montanari, Alberto

    2016-04-01

    Evaluation of scientific impact is becoming an essential step all over the world for assigning academic positions, funding and recognition. Impact is generally assessed by means of objective bibliometric indicators which are frequently integrated with a subjective evaluation by one or more individuals. An essential requirement of impact assessment is to ensure balance across several potential discriminating factors, including gender, ethnics, culture, scientific field and many others. Scientific associations need to ensure balance in any step of their activity and in particular when electing their representatives, evaluating scientific contributions, reviewing papers and assigning awards. While ensuring balance is a strict necessity, how to get to target is still a matter of vivid debates. In fact, the context of science is very different with respect to the general context of society and the need for scientific associations to maintain confidentiality in their evaluation procedures makes the application of transparent procedures more complicated. This talk aims to present the experience and the efforts of the European Geosciences Union to ensure balance, with a particular focus on gender balance. Data and statistics will be presented in the attempt to provide constructive indications to get to the target of giving equal opportunities to researchers across gender, continents and ethnic groups. Science is a unifying discipline and balance will be vital to ensure that humans and our planet co-evolve sustainably.

  18. Approximate ballistics formulas for spherical pellets in free flight

    Directory of Open Access Journals (Sweden)

    E.J. Allen

    2018-02-01

    Full Text Available The ballistics equations for spherical pellets in free flight are simplified through appropriate scaling of the pellet velocity and pellet distance. Two different drag coefficient curves are averaged to yield a single curve applicable to shot pellets and round balls. The resulting S-shaped drag coefficient curve is approximated by three straight-line segments. The scaled ballistics equations are then solved exactly and simple formulas are found for the velocity and flight time with respect to trajectory distance. The formulas are applicable to spherical shot pellets and round balls of any composition under any atmospheric conditions. The formulas are amenable to quick and easy computation and may also serve as an aid in understanding and comparing black-box ballistics calculators. For shotshell ballistics, an important assumption in the present investigation is that the pellets are moving as single, free spheres and not as a dense cloud or in a shot column, in particular, the pellets are not interacting during flight. Therefore, the formulas are most appropriate for single round balls, for large shot sizes, and for pellets of small shot size fired from open chokes. The formulas are clear and accessible, and can be implemented by military or law enforcement personnel as well as hunters and shooters. This work differs from previous investigations in that accurate ballistics formulas are derived for spherical projectiles of shotguns and muzzleloaders using realistic drag coefficients.

  19. Transition to ballistic regime for heat transport in helium II

    Energy Technology Data Exchange (ETDEWEB)

    Sciacca, Michele, E-mail: michele.sciacca@unipa.it [Dipartimento Scienze Agrarie e Forestali, Università degli studi di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia (Spain); Sellitto, Antonio, E-mail: ant.sellitto@gmail.com [Dipartimento di Matematica, Informatica ed Economia, Università della Basilicata, Campus Macchia Romana, 85100 Potenza (Italy); Jou, David, E-mail: david.jou@uab.cat [Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia (Spain); Institut d' Estudis Catalans, Carme 47, 08001 Barcelona, Catalonia (Spain)

    2014-07-04

    The size-dependent and flux-dependent effective thermal conductivity of narrow capillaries filled with superfluid helium is analyzed from a thermodynamic continuum perspective. The classical Landau evaluation of the effective thermal conductivity of quiescent superfluid, or the Gorter–Mellinck regime of turbulent superfluids, is extended to describe the transition to ballistic regime in narrow channels wherein the radius R is comparable to (or smaller than) the phonon mean-free path ℓ in superfluid helium. To do so, we start from an extended equation for the heat flux incorporating non-local terms, and take into consideration a heat slip flow along the walls of the tube. This leads from an effective thermal conductivity proportional to R{sup 2} (Landau regime) to another one proportional to Rℓ (ballistic regime). We consider two kinds of flows: along cylindrical pipes and along two infinite parallel plates. - Highlights: • Heat transport in counterflow helium in the ballistic regime. • The one-fluid model based on the Extended Thermodynamics is used. • The transition from the Landau regime to the ballistic regime. • The transition from quantum turbulence to ballistic regime.

  20. Ballistic heat conduction and mass disorder in one dimension

    International Nuclear Information System (INIS)

    Ong, Zhun-Yong; Zhang, Gang

    2014-01-01

    It is well-known that in the disordered harmonic chain, heat conduction is subballistic and the thermal conductivity (κ) scales asymptotically as lim L→∞ κ∝L 0.5 where L is the chain length. However, using the nonequilibrium Green's function (NEGF) method and analytical modelling, we show that there exists a critical crossover length scale (L C ) below which ballistic heat conduction (κ∝L) can coexist with mass disorder. This ballistic-to-subballistic heat conduction crossover is connected to the exponential attenuation of the phonon transmittance function Ξ i.e. Ξ(ω, L) = exp[−L/λ(ω)], where λ is the frequency-dependent attenuation length. The crossover length can be determined from the minimum attenuation length, which depends on the maximum transmitted frequency. We numerically determine the dependence of the transmittance on frequency and mass composition as well as derive a closed form estimate, which agrees closely with the numerical results. For the length-dependent thermal conductance, we also derive a closed form expression which agrees closely with numerical results and reproduces the ballistic to subballistic thermal conduction crossover. This allows us to characterize the crossover in terms of changes in the length, mass composition and temperature dependence, and also to determine the conditions under which heat conduction enters the ballistic regime. We describe how the mass composition can be modified to increase ballistic heat conduction. (paper)

  1. Ballistic Application of Coir Fiber Reinforced Epoxy Composite in Multilayered Armor

    OpenAIRE

    Luz, Fernanda Santos da; Monteiro, Sergio Neves; Lima, Eduardo Sousa; Lima Júnior, Édio Pereira

    2017-01-01

    Multilayered armor systems (MAS) composed of relatively lighter materials with capacity to provide personal ballistic protection are being extensively investigated and used in armor vests. A typical MAS to stand high impact energy 7.62 mm bullet has a front ceramic followed by an aramid fabric laminate, such as Kevlar™. Since both the army and municipal police personnel might need to wear an armor vest, a large number of vests needs to be supplied. In the case of Kevlar™, one of the most expe...

  2. Energy Absorption and Dynamic Deformation of Backing Material for Ballistic Evaluation of Body Armour

    OpenAIRE

    Debarati Bhattacharjee; Ajay Kumar; Ipsita Biswas

    2014-01-01

    The measurement of back face signature (BFS) or behind armour blunt trauma (BABT) is a critical aspect of ballistic evaluation of body armour. BFS is the impact experienced by the armour wearing body, when subjected to a non-penetrating projectile. Mineral or polymeric clay is used to measure the BFS. In addition to stopping the projectile, the body armour can be used only when the BFS also falls within permissible limits. The extent of the BFS depends upon the behavior of the backing materia...

  3. Hypervelocity impacts into porous graphite: experiments and simulations.

    Science.gov (United States)

    Hébert, D; Seisson, G; Rullier, J-L; Bertron, I; Hallo, L; Chevalier, J-M; Thessieux, C; Guillet, F; Boustie, M; Berthe, L

    2017-01-28

    We present experiments and numerical simulations of hypervelocity impacts of 0.5 mm steel spheres into graphite, for velocities ranging between 1100 and 4500 m s -1 Experiments have evidenced that, after a particular striking velocity, depth of penetration no longer increases but decreases. Moreover, the projectile is observed to be trapped below the crater surface. Using numerical simulations, we show how this experimental result can be related to both materials, yield strength. A Johnson-Cook model is developed for the steel projectile, based on the literature data. A simple model is proposed for the graphite yield strength, including a piecewise pressure dependence of the Drucker-Prager form, which coefficients have been chosen to reproduce the projectile penetration depth. Comparisons between experiments and simulations are presented and discussed. The damage properties of both materials are also considered, by using a threshold on the first principal stress as a tensile failure criterion. An additional compressive failure model is also used for graphite when the equivalent strain reaches a maximum value. We show that the experimental crater diameter is directly related to the graphite spall strength. Uncertainties on the target yield stress and failure strength are estimated.This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'. © 2016 The Author(s).

  4. What Should Be the United States Policy towards Ballistic Missile Defense for Northeast Asia?

    National Research Council Canada - National Science Library

    Delgado, Roberto L

    2005-01-01

    .... The threat of ballistic missiles from Northeast Asia is especially high. China and North Korea are seen as the top threats in the region when it comes to the delivery of WMD through ballistic missiles...

  5. Interaction of a ballistic probe with gaseous media

    International Nuclear Information System (INIS)

    Kucerovsky, Zden; Greason, William D

    2008-01-01

    Free-flying metal probes are used to determine charge densities in gaseous media containing free charge or low density plasma. The trajectory of the probe is ensured either by gravity or by propelling the probe to a certain velocity at the launch site. While travelling, the probe charge changes from its launch-site magnitude to that related to the space charge density existing along the trajectory. The degree to which the probe's arrival-site charge magnitude matches the space charge density in the area of interest depends on the probe shape and on the charge exchange processes between the probe body and the medium. The paper studies a probe acting as a free-flying charge carrier in air, and discusses the problems that may lead to an imbalance between the charge collected by the probe in the area of interest and the charge measured at the arrival site. The analysis and the described experiments are of the ballistic type: a small, triboelectrically pre-charged metal probe was propelled on a horizontal path, and the charge carried by the probe was measured at several points along the trajectory by means of contact-free induction rings; the initial and final charges were determined by static Faraday cups. A charge disparity was found under certain conditions, and its degree explained by the effects of the charge carrier potential. The studied probe charges ranged from 10 to 50 nF, and the fly-times needed to cross a one-meter path ranged from 20 to 40 ms. The probe to gas charge exchange experiments and their analysis yielded conditions under which the probe lost approximately 10 % of its charge. The results of our study may be of interest to those who intend to use the free-flying probe technique for the determination of space charge density.

  6. Kinetics of diffusion-controlled and ballistically-controlled reactions

    International Nuclear Information System (INIS)

    Redner, S.

    1995-01-01

    The kinetics of diffusion-controlled two-species annihilation, A+B → O and single-species ballistically-controlled annihilation, A+A → O are investigated. For two-species annihilation, we describe the basic mechanism that leads to the formation of a coarsening mosaic of A- and B-domains. The implications of this picture on the distribution of reactants is discussed. For ballistic annihilation, dimensional analysis shows that the concentration and rms velocity decay as c∼t -α and v∼t -β , respectively, with α+β = 1 in any spatial dimension. Analysis of the Boltzmann equation for the evolution of the velocity distribution yields accurate predictions for the kinetics. New phenomena associated with discrete initial velocity distributions and with mixed ballistic and diffusive reactant motion are also discussed. (author)

  7. Ballistic spin filtering across the ferromagnetic-semiconductor interface

    Directory of Open Access Journals (Sweden)

    Y.H. Li

    2012-03-01

    Full Text Available The ballistic spin-filter effect from a ferromagnetic metal into a semiconductor has theoretically been studied with an intention of detecting the spin polarizability of density of states in FM layer at a higher energy level. The physical model for the ballistic spin filtering across the interface between ferromagnetic metals and semiconductor superlattice is developed by exciting the spin polarized electrons into n-type AlAs/GaAs superlattice layer at a much higher energy level and then ballistically tunneling through the barrier into the ferromagnetic film. Since both the helicity-modulated and static photocurrent responses are experimentally measurable quantities, the physical quantity of interest, the relative asymmetry of spin-polarized tunneling conductance, could be extracted experimentally in a more straightforward way, as compared with previous models. The present physical model serves guidance for studying spin detection with advanced performance in the future.

  8. Ballistic Anisotropic Magnetoresistance of Single-Atom Contacts.

    Science.gov (United States)

    Schöneberg, J; Otte, F; Néel, N; Weismann, A; Mokrousov, Y; Kröger, J; Berndt, R; Heinze, S

    2016-02-10

    Anisotropic magnetoresistance, that is, the sensitivity of the electrical resistance of magnetic materials on the magnetization direction, is expected to be strongly enhanced in ballistic transport through nanoscale junctions. However, unambiguous experimental evidence of this effect is difficult to achieve. We utilize single-atom junctions to measure this ballistic anisotropic magnetoresistance (AMR). Single Co and Ir atoms are deposited on domains and domain walls of ferromagnetic Fe layers on W(110) to control their magnetization directions. They are contacted with nonmagnetic tips in a low-temperature scanning tunneling microscope to measure the junction conductances. Large changes of the magnetoresistance occur from the tunneling to the ballistic regime due to the competition of localized and delocalized d-orbitals, which are differently affected by spin-orbit coupling. This work shows that engineering the AMR at the single atom level is feasible.

  9. Development of high-density ceramic composites for ballistic applications

    International Nuclear Information System (INIS)

    Rupert, N.L.; Burkins, M.S.; Gooch, W.A.; Walz, M.J.; Levoy, N.F.; Washchilla, E.P.

    1993-01-01

    The application of ceramic composites for ballistic application has been generally developed with ceramics of low density, between 2.5 and 4.5 g/cm 2 . These materials have offered good performance in defeating small-caliber penetrators, but can suffer time-dependent degradation effects when thicker ceramic tiles are needed to defeat modem, longer, heavy metal penetrators that erode rather than break up. This paper addresses the ongoing development, fabrication procedures, analysis, and ballistic evaluation of thinner, denser ceramics for use in armor applications. Nuclear Metals Incorporated (NMI) developed a process for the manufacture of depleted uranium (DU) ceramics. Samples of the ceramics have been supplied to the US Army Research Laboratory (ARL) as part of an unfunded cooperative study agreement. The fabrication processes used, characterization of the ceramic, and a ballistic comparison between the DU-based ceramic with baseline Al 2 O 3 will be presented

  10. Design and Manufacturing Process for a Ballistic Missile

    Directory of Open Access Journals (Sweden)

    Zaharia Sebastian Marian

    2016-12-01

    Full Text Available Designing a ballistic missile flight depends on the mission and the stress to which the missile is subject. Missile’s requests are determined by: the organization of components; flight regime type, engine configuration and aerodynamic performance of the rocket flight. In this paper has been developed a ballistic missile with a smooth fuselage type, 10 control surfaces, 8 directional surfaces for cornering execution, 2 for maneuvers of execution to change the angle of incidence and 4 stabilizers direction. Through the technology of gluing and clamping of the shell and the use of titanium components, mass of ballistic missile presented a significant decrease in weight and a structure with high strength.

  11. Media Impacts on Women's Fertility Desires: A Prolonged Exposure Experiment.

    Science.gov (United States)

    Knobloch-Westerwick, Silvia; Willis, Laura E; Kennard, Ashley R

    2016-06-01

    Media exposure may have implications for family planning, a public health issue of key importance. Drawing on social comparison theory and social identity theory, a prolonged exposure experiment examined whether media portrayals of women's social roles affect fertility desires among 166 American, nonstudent, never married, childless women ages 21-35 years old. After sign-up and baseline sessions, participants viewed magazine pages five days in a row. Stimuli presented women in either mother/homemaker roles, beauty ideal roles, or professional roles. Three days later, participants again indicated their number of desired children and time planned until first birth. Exposure to mother/homemaker and beauty ideal portrayals increased the number of desired children across time. Exposure to professional portrayals increased the time planned until 1st birth compared to beauty ideal portrayals-this impact was partially mediated by a shift toward more progressive gender norms (per social identity theory) and assimilation (per social comparison theory).

  12. Measurement of Damage Velocities in Bullet Impacts of Transparent Armor

    Science.gov (United States)

    Anderson, Charles; Bigger, Rory; Weiss, Carl

    2013-06-01

    A series of impact experiments have been conducted to examine the response of transparent material to ballistic impact. The experiments consisted of impacting 15 mm of borosilicate glass back by 9.5 mm of Lexan. The projectile was a 0.30-cal hard steel bullet designed specifically for the experiments. Residual velocities and the residual length of the bullets (which were soft-recovered in a catch box) were measured as a function of impact velocity. High-speed imaging of the impact event and post-test analysis has permitted quantification of damage propagation and the rate of propagation. The results of several experiments are presented and compared to edge-on impact experiments that have been conducted by Strassburger et al..

  13. Coupling between a Langmuir wave and a ballistic perturbation

    International Nuclear Information System (INIS)

    Gervais, F.; Olivain, J.; Quemeneur, A.; Trocheris, M.

    1980-01-01

    The study of the mode-mode coupling usually neglects the ballistic contribution associated with parent waves. If this approximation is not made, a new mode, resulting from the interaction between the ballistic perturbation of pulsation ω 2 associated with one launched wave and the Landau component of pulsation ω 1 of the second one appears if ω 1 >ω 2 . The problem is solved theoretically and experimental evidence of this mode from measurements performed on a D.C. plasma column, confirms the results of this analysis

  14. Ballistics for neurosurgeons: Effects of firearms of customized cranioplasty implants

    OpenAIRE

    Lemcke, Johannes; L?ser, Rainer; Telm, Andreas; Meier, Ullrich

    2013-01-01

    Introduction: There are about 33,000 deaths caused by gunshot wounds in the USA each year. Probably half of these deaths result from head wounds. Among US Army soldiers, 17% of all ballistic injuries are head wounds. This means that, even in those protected by ballistic helmets, gunshot injuries to the head represent a danger. The aim of this study was to examine the effects of shelling of computer-aided designed (CAD) cranioplasty implants made of two different materials. Methods: An experim...

  15. Quantifying Uncertainty from Computational Factors in Simulations of a Model Ballistic System

    Science.gov (United States)

    2017-08-01

    Ballistic System by Daniel J Hornbaker Approved for public release; distribution is unlimited. NOTICES...Uncertainty from Computational Factors in Simulations of a Model Ballistic System by Daniel J Hornbaker Weapons and Materials Research...November 2016 4. TITLE AND SUBTITLE Quantifying Uncertainty from Computational Factors in Simulations of a Model Ballistic System 5a. CONTRACT NUMBER

  16. Molecular Dynamics Modeling of the Effect of Axial and Transverse Compression on the Residual Tensile Properties of Ballistic Fiber

    Directory of Open Access Journals (Sweden)

    Sanjib C. Chowdhury

    2017-02-01

    Full Text Available Ballistic impact induces multiaxial loading on Kevlar® and polyethylene fibers used in protective armor systems. The influence of multiaxial loading on fiber failure is not well understood. Experiments show reduction in the tensile strength of these fibers after axial and transverse compression. In this paper, we use molecular dynamics (MD simulations to explain and develop a fundamental understanding of this experimental observation since the property reduction mechanism evolves from the atomistic level. An all-atom MD method is used where bonded and non-bonded atomic interactions are described through a state-of-the-art reactive force field. Monotonic tension simulations in three principal directions of the models are conducted to determine the anisotropic elastic and strength properties. Then the models are subjected to multi-axial loads—axial compression, followed by axial tension and transverse compression, followed by axial tension. MD simulation results indicate that pre-compression distorts the crystal structure, inducing preloading of the covalent bonds and resulting in lower tensile properties.

  17. Gate controlled high efficiency ballistic energy conversion system

    NARCIS (Netherlands)

    Xie, Yanbo; Bos, Diederik; de Boer, Hans L.; van den Berg, Albert; Eijkel, Jan C.T.; Zengerle, R.

    2013-01-01

    Last year we demonstrated the microjet ballistic energy conversion system[1]. Here we show that the efficiency of such a system can be further improved by gate control. With gate control the electrical current generation is enhanced a hundred times with respect to the current generated from the zeta

  18. Aerodynamic heating of ballistic missile including the effects of gravity

    Indian Academy of Sciences (India)

    The aerodynamic heating of a ballistic missile due to only convection is analysed taking into consideration the effects of gravity. The amount of heat transferred to the wetted area and to the nose region has been separately determined, unlike A Miele's treatise without consideration of gravity. The peak heating ratesto the ...

  19. Aerodynamic heating of ballistic missile including the effects of gravity

    Indian Academy of Sciences (India)

    Abstract. The aerodynamic heating of a ballistic missile due to only convection is analysed taking into consideration the effects of gravity. The amount of heat transferred to the wetted area and to the nose region has been separately determined, unlike A Miele's treatise without consideration of gravity. The peak heating rates ...

  20. The application of computed tomography in wound ballistics research

    Science.gov (United States)

    Tsiatis, Nick; Moraitis, Konstantinos; Papadodima, Stavroula; Spiliopoulou, Chara; Kelekis, Alexis; Kelesis, Christos; Efstathopoulos, Efstathios; Kordolaimi, Sofia; Ploussi, Agapi

    2015-09-01

    In wound ballistics research there is a relationship between the data that characterize a bullet and the injury resulted after shooting when it perforates the human body. The bullet path in the human body following skin perforation as well as the damaging effect cannot always be predictable as they depend on various factors such as the bullet's characteristics (velocity, distance, type of firearm and so on) and the tissue types that the bullet passes through. The purpose of this presentation is to highlight the contribution of Computed Tomography (CT) in wound ballistics research. Using CT technology and studying virtual “slices” of specific areas on scanned human bodies, allows the evaluation of density and thickness of the skin, the subcutaneous tissue, the muscles, the vital organs and the bones. Density data taken from Hounsfield units can be converted in g/ml by using the appropriate software. By evaluating the results of this study, the anatomy of the human body utilizing ballistic gel will be reproduced in order to simulate the path that a bullet follows. The biophysical analysis in wound ballistics provides another application of CT technology, which is commonly used for diagnostic and therapeutic purposes in various medical disciplines.

  1. Quantum ballistic evolution in quantum mechanics: Application to quantum computers

    International Nuclear Information System (INIS)

    Benioff, P.

    1996-01-01

    Quantum computers are important examples of processes whose evolution can be described in terms of iterations of single-step operators or their adjoints. Based on this, Hamiltonian evolution of processes with associated step operators T is investigated here. The main limitation of this paper is to processes which evolve quantum ballistically, i.e., motion restricted to a collection of nonintersecting or distinct paths on an arbitrary basis. The main goal of this paper is proof of a theorem which gives necessary and sufficient conditions that T must satisfy so that there exists a Hamiltonian description of quantum ballistic evolution for the process, namely, that T is a partial isometry and is orthogonality preserving and stable on some basis. Simple examples of quantum ballistic evolution for quantum Turing machines with one and with more than one type of elementary step are discussed. It is seen that for nondeterministic machines the basis set can be quite complex with much entanglement present. It is also proven that, given a step operator T for an arbitrary deterministic quantum Turing machine, it is decidable if T is stable and orthogonality preserving, and if quantum ballistic evolution is possible. The proof fails if T is a step operator for a nondeterministic machine. It is an open question if such a decision procedure exists for nondeterministic machines. This problem does not occur in classical mechanics. Also the definition of quantum Turing machines used here is compared with that used by other authors. copyright 1996 The American Physical Society

  2. Phase conjugated Andreev backscattering in two-dimensional ballistic cavities

    NARCIS (Netherlands)

    Morpurgo, A.F.; Holl, S.; Wees, B.J.van; Klapwijk, T.M; Borghs, G.

    1997-01-01

    We have experimentally investigated transport in two-dimensional ballistic cavities connected to a point contact and to two superconducting electrodes with a tunable macroscopic phase difference. The point contact resistance oscillates as a function of the phase difference in a way which reflects

  3. Noninteracting beams of ballistic two-dimensional electrons

    International Nuclear Information System (INIS)

    Spector, J.; Stormer, H.L.; Baldwin, K.W.; Pfeiffer, L.N.; West, K.W.

    1991-01-01

    We demonstrate that two beams of two-dimensional ballistic electrons in a GaAs-AlGaAs heterostructure can penetrate each other with negligible mutual interaction analogous to the penetration of two optical beams. This allows electrical signal channels to intersect in the same plane with negligible crosstalk between the channels

  4. Mechanical properties of silicone based composites as a temperature insensitive ballistic backing material for quantifying back face deformation.

    Science.gov (United States)

    Edwards, Tara D; Bain, Erich D; Cole, Shawn T; Freeney, Reygan M; Halls, Virginia A; Ivancik, Juliana; Lenhart, Joseph L; Napadensky, Eugene; Yu, Jian H; Zheng, James Q; Mrozek, Randy A

    2018-04-01

    This paper describes a new witness material for quantifying the back face deformation (BFD) resulting from high rate impact of ballistic protective equipment. Accurate BFD quantification is critical for the assessment and certification of personal protective equipment, such as body armor and helmets, and ballistic evaluation. A common witness material is ballistic clay, specifically, Roma Plastilina No. 1 (RP1). RP1 must be heated to nearly 38°C to pass calibration, and used within a limited time frame to remain in calibration. RP1 also exhibits lot-to-lot variability and is sensitive to time, temperature, and handling procedures, which limits the BFD accuracy and reproducibility. A new silicone composite backing material (SCBM) was developed and tested side-by-side with heated RP1 using quasi-static indentation and compression, low velocity impact, spherical projectile penetration, and both soft and hard armor ballistic BFD measurements to compare their response over a broad range of strain rates and temperatures. The results demonstrate that SCBM mimics the heated RP1 response at room temperature and exhibits minimal temperature sensitivity. With additional optimization of the composition and processing, SCBM could be a drop-in replacement for RP1 that is used at room temperature during BFD quantification with minimal changes to the current RP1 handling protocols and infrastructure. It is anticipated that removing the heating requirement, and temperature-dependence, associated with RP1 will reduce test variability, simplify testing logistics, and enhance test range productivity. Published by Elsevier B.V.

  5. Experimental studies of the physical process for forming the profile of a friction unit in a ballistic installation

    Science.gov (United States)

    Guskov, A. V.; Kormushkin, M. A.; Milevskii, K. E.

    2017-11-01

    In the paper, physical processes were identified and investigated when the device being thrown in a ballistic installation moved. A set of methods for studying the processes that occur during the operation of the friction unit of the device being thrashed was developed. The process of plastic deformation during the formation of a friction unit of a device being thrashed, made of high-carbon steel, was studied. The process of forming a profile on the friction unit was studied, and the influence of the geometric parameters of the profile of the inner surface of the ballistic installation on the specific pressure of the formation of the friction unit of the device being thrown was determined. On the basis of practical experiments, conclusions were drawn about the effect of the geometric parameters of the friction unit profile on the punching force.

  6. Simulation of depth of penetration during ballistic impact on thick ...

    Indian Academy of Sciences (India)

    law of motion for the entire body, treating it as a rigid mass, is obtained (Forrestal et al 1995). Awerbuch & Bodner (1974) developed a mathematical model to describe the mechanics of nor- mal perforation (complete penetration) of projectile into metal targets. This model seems capable of predicting residual velocity of ...

  7. Legislative Environmental Impact Statement: Small Intercontinental Ballistic Missile Program.

    Science.gov (United States)

    1986-11-01

    85 and 95. In the Yuma PG area, areas of special visual quality are found in the vicinity of the Colorado River, the Muggins and Castle Dome moun...assemblages occur in several exposed localities east of the ROI. Floral assemblages and sparse invertebrate materials occur in the Pleistocene Citronelle ...PSD Class I areas include Kings Canyon-Sequoia National Park, Dome Land Wilderness, San Gabriel Wilderness, Cucamonga Wilderness, San Gorgonio

  8. Methods for Analysis and Simulation of Ballistic Impact

    Science.gov (United States)

    2017-04-01

    frictional effects, for example [38, 39, 23]. Fig. (1). Extended hydrodynamic theory based on dimensional analysis applied to aluminum oxide (top) and...though not always in closed form. In §3.2, another 1-D treatment is presented for analysis of planar shock waves, where steady state behavior is...Eng., Vol. 85, pp. 124–131, 2015. [11] J. Clayton, “Dimensional analysis and extended hydrodynamic theory applied to long-rod penetration of ceramics

  9. Ballistic Missile Defense System (BMDS) Programmatic Environmental Impact Statement

    Science.gov (United States)

    2007-01-01

    UCS K.2.1 Cahn Alma DC_M3467 UCS K.2.1 Cahoon Ruth DC_M3880 UCS K.2.1 Cain Art DC_M3371 UCS K.2.1 Calabria Antonio DC_M0629 K.2.1 Calabria Antonio...Alliance for World Security K.3.2, K.3.3, K.3.10, K.3.13, K.3.14, K.4 Flesch Alma S. DC_M2852 UCS K.2.1 Fleshman Joyce DC_M6805 UCS K.2.1 Flodin Betty...Reed, C.S. Ginter, and N. Carrasco , 2003. The sodium/iodide Symporter (NIS): Characterization, regulation, and medical significance. Endocrine

  10. Ballistic Missile Defense Final Programmatic Environmental Impact Statement

    Science.gov (United States)

    1994-10-01

    or informal conasultation with the U.S. Fiah and aoaroro daring the antelope fawaiog peeied wad yearloag for desert bighorn Wildlife= ceee oaceening... catalogued , thereby making missiles easier to identify and shortening response time. F.4.3 ELEMENT DESCRIPTION The SBS element would consist of a

  11. Effects of Ceramic Type on Fragmentation Behaviour during Ballistic Impact

    Science.gov (United States)

    1992-06-01

    confined targets, the debris fromn within the fracture conoid was separated from the ceramic outside the conoid , and its size distribution determined...stress wave interactions. fragent ue fr (tp tobottm) ~As an approximation, tile frrtur ..\\i99S alkmitt in and z.i ron a T conoid is easily separated from...hasS-’,::,ly high proportion of finc fragments within this region, e\\cn fragments up".0 1 in size being mostly produced within the conoid . Vcry few of

  12. Ballistic tongue projection in chameleons maintains high performance at low temperature.

    Science.gov (United States)

    Anderson, Christopher V; Deban, Stephen M

    2010-03-23

    Environmental temperature impacts the physical activity and ecology of ectothermic animals through its effects on muscle contractile physiology. Sprinting, swimming, and jumping performance of ectotherms decreases by at least 33% over a 10 degrees C drop, accompanied by a similar decline in muscle power. We propose that ballistic movements that are powered by recoil of elastic tissues are less thermally dependent than movements that rely on direct muscular power. We found that an elastically powered movement, ballistic tongue projection in chameleons, maintains high performance over a 20 degrees C range. Peak velocity and power decline by only 10%-19% with a 10 degrees C drop, compared to >42% for nonelastic, muscle-powered tongue retraction. These results indicate that the elastic recoil mechanism circumvents the constraints that low temperature imposes on muscle rate properties and thereby reduces the thermal dependence of tongue projection. We propose that organisms that use elastic recoil mechanisms for ecologically important movements such as feeding and locomotion may benefit from an expanded thermal niche.

  13. Imaging ballistic carrier trajectories in graphene using scanning gate microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Morikawa, Sei; Masubuchi, Satoru [Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan); Dou, Ziwei; Wang, Shu-Wei; Smith, Charles G.; Connolly, Malcolm R., E-mail: mrc61@cam.ac.uk [Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE (United Kingdom); Watanabe, Kenji; Taniguchi, Takashi [National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan); Machida, Tomoki, E-mail: tmachida@iis.u-tokyo.ac.jp [Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan); Institute for Nano Quantum Information Electronics, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan)

    2015-12-14

    We use scanning gate microscopy to map out the trajectories of ballistic carriers in high-mobility graphene encapsulated by hexagonal boron nitride and subject to a weak magnetic field. We employ a magnetic focusing geometry to image carriers that emerge ballistically from an injector, follow a cyclotron path due to the Lorentz force from an applied magnetic field, and land on an adjacent collector probe. The local electric field generated by the scanning tip in the vicinity of the carriers deflects their trajectories, modifying the proportion of carriers focused into the collector. By measuring the voltage at the collector while scanning the tip, we are able to obtain images with arcs that are consistent with the expected cyclotron motion. We also demonstrate that the tip can be used to redirect misaligned carriers back to the collector.

  14. Earth to Mars Ballistic Mission Opportunities from Naro Space Center

    Directory of Open Access Journals (Sweden)

    Sung-Moon Yoo

    2003-12-01

    Full Text Available Earth to Mars ballistic mission opportunities from Naro Space Center are studied. Determining ballistic mission opportunities can be divided into two major parts, i.e. the launch window and the daily launch window determination. At the launch window determination parts, Porkchop diagrams of Earth launch C3 magnitude, total mission duration, declination of V∞ vector at the Earth launch, and declination & right ascension of V∞ vector at the Mars arrival are examined. The location of launch site and rotation effects of the Earth are considered during the daily launch window determination parts. Using Lambert method, various Porkchop diagrams of launching in 2027 are examined for example. The daily launch window of Naro Space Center at that year was checked to verify the launch possibility by comparing with the Kennedy Space Center.

  15. Pivotal role of ballistic and quasi-ballistic electrons on LED efficiency

    Science.gov (United States)

    Ni, X.; Li, X.; Lee, J.; Liu, S.; Avrutin, V.; Matulionis, A.; Özgür, Ü.; Morkoç, H.

    2010-08-01

    Significant progress in the power conversion efficiency and brightness of InGaN-based light emitting diodes (LEDs) has paved the way for these devices to be considered for LED lighting. In this realm, however, the efficiency must be retained at high injection levels in order to generate the lumens required. Unfortunately, LEDs undergo a monotonic efficiency degradation starting at current densities even lower than 50 A/cm 2 which would hinder LED insertion into the general lighting market. The physical origins for the loss of efficiency retention are at present a topic of intense debate given its enormous implications. This paper reviews the current status of the field regarding the mechanisms that have been put forward as being responsible for the loss of efficiency, such as Auger recombination, electron overflow (spillover), current crowding, asymmetric injection of electrons and holes, and poor transport of holes through the active region, the last one being applicable to multiple quantum well designs. While the Auger recombination received early attention, increasing number of researchers seem to think otherwise at the moment in that it alone (if any) cannot explain the progressively worsening loss of efficiency reduction as the InN mole fraction is increased. Increasing number of reports seems to suggest that the electron overflow is one of the major causes of efficiency degradation. The physical driving force for this is likely to be the relatively poor hole concentration and transport, and skewed injection favoring electrons owing to their relatively high concentration. Most intriguingly there is recent experimental convincing evidence to suggest that quasi-ballistic electrons in the active region, which are not able to thermalize within the residence time and possibly longitudinal optical phonon lifetime, contribute to the carrier overflow which would require an entirely new thought process in the realm of LEDs.

  16. Sino-Japanese relations and ballistic missile defence

    OpenAIRE

    Hughes, Christopher W.

    2001-01-01

    Since December 1998, the Japanese government has formally committed itself to undertake cooperative technological research with the US into Ballistic Missile Defence (BMD). Japanese government policy-makers stress that the BMD project remains at present purely at the research stage, and that separate government decisions will be necessary before any progression towards the stages of development, production and deployment. Nevertheless, even at the research phase it is clear that both Japanese...

  17. Ballistic Phonon Penetration Depth in Amorphous Silicon Dioxide.

    Science.gov (United States)

    Yang, Lin; Zhang, Qian; Cui, Zhiguang; Gerboth, Matthew; Zhao, Yang; Xu, Terry T; Walker, D Greg; Li, Deyu

    2017-12-13

    Thermal transport in amorphous silicon dioxide (a-SiO 2 ) is traditionally treated as random walks of vibrations owing to its greatly disordered structure, which results in a mean free path (MFP) approximately the same as the interatomic distance. However, this picture has been debated constantly and in view of the ubiquitous existence of thin a-SiO 2 layers in nanoelectronic devices, it is imperative to better understand this issue for precise thermal management of electronic devices. Different from the commonly used cross-plane measurement approaches, here we report on a study that explores the in-plane thermal conductivity of double silicon nanoribbons with a layer of a-SiO 2 sandwiched in-between. Through comparing the thermal conductivity of the double ribbon samples with that of corresponding single ribbons, we show that thermal phonons can ballistically penetrate through a-SiO 2 of up to 5 nm thick even at room temperature. Comprehensive examination of double ribbon samples with various oxide layer thicknesses and van der Waals bonding strengths allows for extraction of the average ballistic phonon penetration depth in a-SiO 2 . With solid experimental data demonstrating ballistic phonon transport through a-SiO 2 , this work should provide important insight into thermal management of electronic devices.

  18. Structural constraints to wilderness: Impacts on visitation and experience

    Science.gov (United States)

    Ingrid E. Schneider; Sierra L. Schroeder; Ann. Schwaller

    2011-01-01

    A significant research body on recreation constraints exists, but wilderness constraints research is limited. Like other recreationists, wilderness visitors likely experience a number of constraints, factors that limit leisure preference formation or participation and enjoyment. This project explored how visitors' experiences with and in wilderness are constrained...

  19. Estimation of sediment properties during benthic impact experiments

    Digital Repository Service at National Institute of Oceanography (India)

    Yamazaki, T.; Sharma, R.

    . The estimates show that the weights of dry (355-1332 t) and wet sediment (1651-4888 t) recovered during the experiments, are not only a function of the total duration and distance covered during the experiment, but also depend on water content and density...

  20. Characterizing Hypervelocity Impact Plasma Through Experiments and Simulations

    Science.gov (United States)

    Close, Sigrid; Lee, Nicolas; Fletcher, Alex; Nuttall, Andrew; Hew, Monica; Tarantino, Paul

    2017-10-01

    Hypervelocity micro particles, including meteoroids and space debris with masses produce a strong electromagnetic pulse (EMP) with a broad frequency spectrum. Subsequent plasma oscillations resulting from instabilities can also emit significant power and may be responsible for many reported satellite anomalies. We present theory and recent results from ground-based impact tests aimed at characterizing hypervelocity impact plasma. We also show results from particle-in-cell (PIC) and computational fluid dynamics (CFD) simulations that allow us to extend to regimes not currently possible with ground-based technology. We show that significant impact-produced radio frequency (RF) emissions occurred in frequencies ranging from VHF through L-band and that these emissions were highly correlated with fast (>20 km/s) impacts that produced a fully ionized plasma.

  1. Game Immersion Experience: Its Hierarchical Structure and Impact on Game-Based Science Learning

    Science.gov (United States)

    Cheng, M.-T.; She, H.-C.; Annetta, L. A.

    2015-01-01

    Many studies have shown the positive impact of serious educational games (SEGs) on learning outcomes. However, there still exists insufficient research that delves into the impact of immersive experience in the process of gaming on SEG-based science learning. The dual purpose of this study was to further explore this impact. One purpose was to…

  2. Small Business Innovation Research Program at the Ballistic Missile Defense Organization

    Science.gov (United States)

    1995-03-21

    8217 ,;;::i’:’.w..:.v,:.’..’,;?.:.:. t OFFICE OF THE INSPECTOR GENERAL SMALL BUSINESS INNOVATION RESEARCH PROGRAM AT THE BALLISTIC...Ballistic Missile Defense Organization Small Business Innovation Research Accession Number: 3526 Publication Date: Mar 21, 1995 Title: Small... Business Innovation Research Program at the Ballistic Missile Defense Organization Corporate Author Or Publisher: DoD, Office of the Inspector General

  3. Determining the Equation of State (EoS) Parameters for Ballistic Gelatin

    Science.gov (United States)

    2015-09-01

    ARL-TR-7467 ● SEP 2015 US Army Research Laboratory Determining the Equation of State (EoS) Parameters for Ballistic Gelatin ...EoS) Parameters for Ballistic Gelatin by Yolin Huang Weapons and Materials Research Directorate, ARL Approved for...State (EoS) Parameters for Ballistic Gelatin 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Yolin Huang 5d

  4. The Impact of Prior Heterosexual Experiences on Homosexuality in Women

    Directory of Open Access Journals (Sweden)

    Marissa A. Harrison

    2008-04-01

    Full Text Available An abundance of unwanted sexual opportunities perpetrated by insensitive, physically and sexually abusive men may be a factor in the expression of homosexuality in some women. In the present study, we examined self-reports of dating histories, sexual experiences, and physical and sexual abuse among lesbians and heterosexual women. Lesbians with prior heterosexual experience reported more severe and more frequent physical abuse by men. Lesbians also reported more instances of forced, unwanted sexual contact perpetrated by men, and this sexual abuse occurred at a significantly earlier age. These data show that adverse experiences with the opposite sex are more common in lesbians than heterosexual women, and therefore negative heterosexual experiences may be a factor in the expression of a same-sex sexual orientation in women. We propose an evolutionary psychological interpretation of this phenomenon based on the cardinally different mating strategies of women and men that have evolved for maximizing the likelihood of reproduction.

  5. NIMS EXPERIMENT DATA RECORDS: SL-9 COMET IMPACT WITH JUPITER

    Data.gov (United States)

    National Aeronautics and Space Administration — NIMS Experiment Data Record (EDR) files contain raw data from the Galileo Orbiter Near-Infrared Mapping Spectrometer (CARLSONETAL1992). This raw data requires...

  6. The impact and applicability of critical experiment evaluations

    International Nuclear Information System (INIS)

    Brewer, R.

    1997-01-01

    This paper very briefly describes a project to evaluate previously performed critical experiments. The evaluation is intended for use by criticality safety engineers to verify calculations, and may also be used to identify data which need further investigation. The evaluation process is briefly outlined; the accepted benchmark critical experiments will be used as a standard for verification and validation. The end result of the project will be a comprehensive reference document

  7. Development of Mortar Simulator with Shell-In-Shell System – Problem of External Ballistics

    Directory of Open Access Journals (Sweden)

    A. Fedaravicius

    2007-01-01

    Full Text Available The shell-in-shell system used in the mortar simulator raises a number of non-standard technical and computational problems starting from the requirement to distribute the propelling blast energy between the warhead and the ballistic barrel, finishing with the requirement that the length of warhead's flight path must be scaled to combat shell firing tables. The design problem of the simulator is split into two parts – the problem of external ballistics where the initial velocities of the warhead must be determined, and the problem of internal ballistics – where the design of the cartridge and the ballistic barrel must be performed.

  8. Influences of nanotwin volume fraction on the ballistic performance of coarse-grained metals

    Directory of Open Access Journals (Sweden)

    Q.D. Ouyang

    2017-09-01

    Full Text Available Coarse-grained (CG metals strengthened by nanotwinned (NT regions possess high strength and good ductility. As such, they are very suitable for applications in bullet-proof targets. Here, a numerical model based on the conventional theory of strain gradient plasticity and the Johnson–Cook failure criterion is employed to study the influences of volume fraction of NT regions on their ballistic performance. The results show that in general a relatively small twin spacing (4–10 nm and a moderate volume fraction (7%–20% will lead to excellent limit velocity and that the influences of volume fraction on limit displacement change with the category of impact processes.

  9. New Diagnostic, Launch and Model Control Techniques in the NASA Ames HFFAF Ballistic Range

    Science.gov (United States)

    Bogdanoff, David W.

    2012-01-01

    This report presents new diagnostic, launch and model control techniques used in the NASA Ames HFFAF ballistic range. High speed movies were used to view the sabot separation process and the passage of the model through the model splap paper. Cavities in the rear of the sabot, to catch the muzzle blast of the gun, were used to control sabot finger separation angles and distances. Inserts were installed in the powder chamber to greatly reduce the ullage volume (empty space) in the chamber. This resulted in much more complete and repeatable combustion of the powder and hence, in much more repeatable muzzle velocities. Sheets of paper or cardstock, impacting one half of the model, were used to control the amplitudes of the model pitch oscillations.

  10. Experimenting with Impacts in a Conceptual Physics or Descriptive Astronomy Laboratory

    Science.gov (United States)

    LoPresto, Michael C.

    2016-01-01

    What follows is a description of the procedure for and results of a simple experiment on the formation of impact craters designed for the laboratory portions of lower mathematical-level general education science courses such as conceptual physics or descriptive astronomy. The experiment provides necessary experience with data collection and…

  11. Socio-economic Impact of Privatisation: The Tanzania Experience ...

    African Journals Online (AJOL)

    In Tanzania and during the short run period privatisation has been both positive and negative effects to the economy. The positive impact seems to outweigh the negative. Positive divestiture results can be measured by the number of firms that have been divested, performance of firms which have already been divested, ...

  12. ATYPICAL DISLOCATION OF IMPACTED PERMANENT TEETH IN CHILDREN. OWN EXPERIENCE.

    Science.gov (United States)

    Janas, Anna; Stelmach, Rafał; Osica, Piotr

    2015-01-01

    Disturbances in forming of the hard tissue of teeth and bones can be a cause of their malformation and translocation. The impact of permanent teeth is one of them. It can occur with translocation of the tooth germ. The aim of the study was to present an atypical translocation of impacted permanent teeth in children. 3.5 year clinical observation was carried out in 14 children (5 girls and 9 boys), aged between 9 and 12 years old. Patients were referred to our Department by orthodontists, paedodontists and General Dental Practitioners, due to impacted permanent teeth. According to the interview, in 8 cases children suffered from a trauma of a facial part of the skull, caused by a fall. On admitance patients were generally healthy. Basing on the clinical and radiological examination, translocation of the impacted permanent teeth has been diagnosed. In 9 cases it concerned medial maxillary incisors, whereas in remaining children--maxillary premolars. The extraction of such teeth has been performed as a part of the one day surgery procedures. In the cases where basing on the radiogram, the position of the tooth allows to predict the latter translocation, the germ has to be extracted.

  13. Health Impact Assessment as a Student Service Learning Experience

    Science.gov (United States)

    Stone, Cynthia; Greene, Marion S.

    2012-01-01

    Health Impact Assessments (HIAs) incorporate a combination of tools, methods, and procedures to evaluate the potential health effects of a proposed program, project, or policy. The university public health department, in collaboration with the county health department, and the local planning organization, developed a curriculum for a…

  14. Does gender impact on female doctors' experiences in the training ...

    African Journals Online (AJOL)

    They expressed concern about finding and maintaining a work-life balance. The gender of their mentor did not impact on the quality of the training but 'bullying' from male peers and selected supervisors occurred. Respondents will continue to recommend the specialty as a satisfying career to young female students.

  15. The impact of sensorimotor experience on affective evaluation of dance

    Directory of Open Access Journals (Sweden)

    Louise eKirsch

    2013-09-01

    Full Text Available Past research demonstrates that we are more likely to positively evaluate a stimulus if we have had previous experience with that stimulus. This has been shown for judgement of faces, architecture, artworks and body movements. In contrast, other evidence suggests that this relationship can also work in the inverse direction, at least in the domain of watching dance. Specifically, it has been shown that in certain contexts, people derive greater pleasure from watching unfamiliar movements they would not be able to physically reproduce compared to simpler, familiar actions they could physically reproduce. It remains unknown, however, how different kinds of experience with complex actions, such as dance, might change observers’ affective judgements of these movements. Our aim was to clarify the relationship between experience and affective evaluation of whole body movements. In a between-subjects design, participants received either physical dance training with a video game system, visual and auditory experience or auditory experience only. Participants’ aesthetic preferences for dance stimuli were measured before and after the training sessions. Results show that participants from the physical training group not only improved their physical performance of the dance sequences, but also reported higher enjoyment and interest in the stimuli after training. This suggests that physically learning particular movements leads to greater enjoyment while observing them. These effects are not simply due to increased familiarity with audio or visual elements of the stimuli, as the other two training groups showed no increase in aesthetic ratings post-training. We suggest these results support an embodied simulation account of aesthetics, and discuss how the present findings contribute to a better understanding of the shaping of preferences by sensorimotor experience.

  16. The impact of sensorimotor experience on affective evaluation of dance

    Science.gov (United States)

    Kirsch, Louise P.; Drommelschmidt, Kim A.; Cross, Emily S.

    2013-01-01

    Past research demonstrates that we are more likely to positively evaluate a stimulus if we have had previous experience with that stimulus. This has been shown for judgment of faces, architecture, artworks and body movements. In contrast, other evidence suggests that this relationship can also work in the inverse direction, at least in the domain of watching dance. Specifically, it has been shown that in certain contexts, people derive greater pleasure from watching unfamiliar movements they would not be able to physically reproduce compared to simpler, familiar actions they could physically reproduce. It remains unknown, however, how different kinds of experience with complex actions, such as dance, might change observers' affective judgments of these movements. Our aim was to clarify the relationship between experience and affective evaluation of whole body movements. In a between-subjects design, participants received either physical dance training with a video game system, visual and auditory experience or auditory experience only. Participants' aesthetic preferences for dance stimuli were measured before and after the training sessions. Results show that participants from the physical training group not only improved their physical performance of the dance sequences, but also reported higher enjoyment and interest in the stimuli after training. This suggests that physically learning particular movements leads to greater enjoyment while observing them. These effects are not simply due to increased familiarity with audio or visual elements of the stimuli, as the other two training groups showed no increase in aesthetic ratings post-training. We suggest these results support an embodied simulation account of aesthetics, and discuss how the present findings contribute to a better understanding of the shaping of preferences by sensorimotor experience. PMID:24027511

  17. The impact of sensorimotor experience on affective evaluation of dance.

    Science.gov (United States)

    Kirsch, Louise P; Drommelschmidt, Kim A; Cross, Emily S

    2013-01-01

    Past research demonstrates that we are more likely to positively evaluate a stimulus if we have had previous experience with that stimulus. This has been shown for judgment of faces, architecture, artworks and body movements. In contrast, other evidence suggests that this relationship can also work in the inverse direction, at least in the domain of watching dance. Specifically, it has been shown that in certain contexts, people derive greater pleasure from watching unfamiliar movements they would not be able to physically reproduce compared to simpler, familiar actions they could physically reproduce. It remains unknown, however, how different kinds of experience with complex actions, such as dance, might change observers' affective judgments of these movements. Our aim was to clarify the relationship between experience and affective evaluation of whole body movements. In a between-subjects design, participants received either physical dance training with a video game system, visual and auditory experience or auditory experience only. Participants' aesthetic preferences for dance stimuli were measured before and after the training sessions. Results show that participants from the physical training group not only improved their physical performance of the dance sequences, but also reported higher enjoyment and interest in the stimuli after training. This suggests that physically learning particular movements leads to greater enjoyment while observing them. These effects are not simply due to increased familiarity with audio or visual elements of the stimuli, as the other two training groups showed no increase in aesthetic ratings post-training. We suggest these results support an embodied simulation account of aesthetics, and discuss how the present findings contribute to a better understanding of the shaping of preferences by sensorimotor experience.

  18. Load and wear experiments on the impact hammer of a vertical shaft impact crusher

    International Nuclear Information System (INIS)

    Yang, J H; Fang, H Y; Luo, M

    2015-01-01

    Impact hammers are important components of impact crushers, and are often shortlived due to the high-impact nature of their use. Wear-resistant alloys are welded to the surface of impact hammers to prolong their service life. In this paper, a simulation model of the rotor and impact hammers in impact crushers was designed to utilize the Discrete Element Method (DEM). The wear-resistant alloy on each impact hammer was divided into twenty-two action regions. The load distribution on each alloy block is affected by the structural and manufacturing parameters of the impact crusher. The wear distribution of the impact hammer was measured by shape morphology according to relative impact crushers. The results demonstrated that the real measurements of wear distribution on the impact hammer were similar to simulated load distribution measurements on the same surface. The study of load distribution of impact hammers by DEM established a theoretical foundation on which to base the optimal design of impact crushers. (paper)

  19. The quasi-ballistic model of electron mobility in liquid hydrocarbons

    International Nuclear Information System (INIS)

    Mozumder, A.

    1996-01-01

    A phenomenological theory of low-mobility liquid hydrocarbons is developed which includes electron ballistic motion in the quasi-free state, in competition with diffusion and trapping. For most low-mobility liquids the theory predicts consistently the effective mobility and activation energy, in agreement with experiments, using quasi-free mobility and trap density respectively as ∼ 100 cm 2 v -1 s -1 and ∼ 10 19 cm -3 . Field dependence of mobility if theoretically of quadratic type for relatively small fields, agreeing approximately with experimental data for n-hexane. Electron scavenging with ''good'' scavengers occurs via the quasi-free state at nearly diffusion-controlled rate; however the effect of large mean free path is seen clearly. (author)

  20. Multi response optimization of wire-EDM process parameters of ballistic grade aluminium alloy

    Directory of Open Access Journals (Sweden)

    Ravindranadh Bobbili

    2015-12-01

    Full Text Available In the current investigation, a multi response optimization technique based on Taguchi method coupled with Grey relational analysis is planned for wire-EDM operations on ballistic grade aluminium alloy for armour applications. Experiments have been performed with four machining variables: pulse-on time, pulse-off time, peak current and spark voltage. Experimentation has been planned as per Taguchi technique. Three performance characteristics namely material removal rate (MRR, surface roughness (SR and gap current (GC have been chosen for this study. Results showed that pulse-on time, peak current and spark voltage were significant variables to Grey relational grade. Variation of performance measures with process variables was modelled by using response surface method. The confirmation tests have also been performed to validate the results obtained by Grey relational analysis and found that great improvement with 6% error is achieved.

  1. The impact of sensorimotor experience on affective evaluation of dance

    NARCIS (Netherlands)

    Kirsch, L.P.; Drommelschmidt, K.A.; Cross, E.S.

    2013-01-01

    Past research demonstrates that we are more likely to positively evaluate a stimulus if we have had previous experience with that stimulus. This has been shown for judgment of faces, architecture, artworks and body movements. In contrast, other evidence suggests that this relationship can also work

  2. Teaching with Videogames: How Experience Impacts Classroom Integration

    Science.gov (United States)

    Bell, Amanda; Gresalfi, Melissa

    2017-01-01

    Digital games have demonstrated great potential for supporting students' learning across disciplines. But integrating games into instruction is challenging and requires teachers to shift instructional practices. One factor that contributes to the successful use of games in a classroom is teachers' experience implementing the technologies. But how…

  3. How Does Sexual Identity Disclosure Impact School Experiences?

    Science.gov (United States)

    Watson, Ryan J.; Wheldon, Christopher W.; Russell, Stephen T.

    2015-01-01

    Lesbian, gay, and bisexual (LGB) individuals disproportionately report negative academic outcomes and experiences as a result of stigma and discrimination. No research to date has investigated how being out in different social relationships may affect these youth. We compare youth who are out to family, friends, and people at school to understand…

  4. Exploring the impact of travel experiences on Italian youth

    African Journals Online (AJOL)

    youth tourism, preferring to focus on workplace expectations and consumer behaviour of the millennial ..... measuring change as a travel benefit, and secondly sharing the results of a Principal Component Analysis (PCA) ..... of measuring the performance post-experience (Pearce, 2011). Moreover, the change dimensions ...

  5. Impact of Advertisements during Channel Zapping on Quality of Experience

    NARCIS (Netherlands)

    Godana, B.E.; Kooij, R.E.; Ahmed, O.K.

    2009-01-01

    Nowadays various digital television services are available. However, the user of these services experiences longer delays than the traditional analog TV while switching from channel to channel. The digital TV operator usually displays a black screen with the channel number during zapping. However,

  6. Impact of advertisements during channel zapping on quality of experience

    NARCIS (Netherlands)

    Godana, B.E.; Kooij, R.E.; Ahmed, O.K.

    2009-01-01

    Nowadays various digital television services are available. However, the user of these services experiences longer delays than the traditional analog TV while switching from channel to channel. The digital TV operator usually displays a black screen with the channel number during zapping. However,

  7. The Impact of Migration on Access to Credit Markets: Experience ...

    African Journals Online (AJOL)

    Experience from Emerging Urban Centres in Tanzania. *Kilima, F.T.M.,1 L. Msese,2 ... can raise labour productivity and effectively engage young people in economic activities both in urban and rural areas. ... dedicated support in training and sensitization to mobilize collective savings and initiate credit services as means to ...

  8. The Impact of Childhood Sexual Abuse on Women's Dental Experiences.

    Science.gov (United States)

    Hays, Kate F.; Stanley, Sheila F.

    1996-01-01

    Compared the dental experiences of 132 women with a history of sexual abuse to 49 women reporting no such history. Findings show that a history of abuse, especially the severity of abuse, predicted different patterns in making and keeping dental appointments, stress-related dental problems, and post-traumatic-stress-disorder-type symptoms while at…

  9. Gridded thermionic gun and integral superconducting ballistic bunch compression cavity

    Energy Technology Data Exchange (ETDEWEB)

    Schultheiss, Thomas [Advanced Energy Systems, Inc., Medford, NY (United States)

    2015-11-16

    general design is a modified ballistic compression cavity pair with two independently powered cells [3]. The first is a cathode cell that includes the thermionic cathode and grid to provide for beam bunching. The second is a full cell with independent phasing and field levels designed to minimize energy spread. The primary goal for Phase II is to manufacture a superconducting gun with a thermionic cathode and imbedded coil. The system developed here is applicable to many high current electron accelerators. The analysis and design constraints imposed by the magnetized cathode make the cathode system developed here more complicated and limited than one without the magnetized beam constraints. High power ERLs would benefit by a gun with the capabilities shown here, 400 mA or more of current. ERLs hold great promise for electron cooling experiments, advanced light sources and Free Electron Lasers. This high current electron injector is a technological advance that will place the requirements for an ERL capable of providing quality bunches needed for cooling within the MEIC circulator ring within reach. This injector would have application to future ERLs around the world.

  10. Flyer impact experiment to study vulnerability and reactivity of gun propellant formulations

    International Nuclear Information System (INIS)

    Bouma, R H B; Boluijt, A G; Verbeek, H J

    2009-01-01

    A flyer impact experiment to study the vulnerability of propellant formulations is designed. The shock wave conditions of the impacting flyer are related to the energy transfer from a single detonating propellant grain as found by numerical simulation. A propellant will react due to the imposed shock from the impacting flyer. The reactivity of the propellant formulation is quantified by the volume of the dent created in an aluminium witness block. This flyer impact experiment simulates the propellant grain-to-grain sympathetic reaction in a shaped charge attack on a gun propellant bed

  11. Flyer impact experiment to study vulnerability and reactivity of gun propellant formulations

    Science.gov (United States)

    Bouma, R. H. B.; Boluijt, A. G.; Verbeek, H. J.

    2009-09-01

    A flyer impact experiment to study the vulnerability of propellant formulations is designed. The shock wave conditions of the impacting flyer are related to the energy transfer from a single detonating propellant grain as found by numerical simulation. A propellant will react due to the imposed shock from the impacting flyer. The reactivity of the propellant formulation is quantified by the volume of the dent created in an aluminium witness block. This flyer impact experiment simulates the propellant grain-to-grain sympathetic reaction in a shaped charge attack on a gun propellant bed.

  12. Cyberbullying among University Students: Gendered Experiences, Impacts, and Perspectives

    OpenAIRE

    Chantal Faucher; Margaret Jackson; Wanda Cassidy

    2014-01-01

    Cyberbullying is an emerging issue in the context of higher education as information and communication technologies (ICT) increasingly become part of daily life in university. This paper presents findings from 1925 student surveys from four Canadian universities. The overall findings are broken down to determine gender similarities and differences that exist between male and female respondents’ backgrounds, ICT usage, experiences with cyberbullying, opinions about the issue, and solutions t...

  13. The impact of sensorimotor experience on affective evaluation of dance

    OpenAIRE

    Louise eKirsch; Kim A. Drommelschmidt; Emily S Cross; Emily S Cross

    2013-01-01

    Past research demonstrates that we are more likely to positively evaluate a stimulus if we have had previous experience with that stimulus. This has been shown for judgement of faces, architecture, artworks and body movements. In contrast, other evidence suggests that this relationship can also work in the inverse direction, at least in the domain of watching dance. Specifically, it has been shown that in certain contexts, people derive greater pleasure from watching unfamiliar movements they...

  14. The impact of sensorimotor experience on affective evaluation of dance

    OpenAIRE

    Kirsch, Louise P.; Drommelschmidt, Kim A.; Cross, Emily S.

    2013-01-01

    Past research demonstrates that we are more likely to positively evaluate a stimulus if we have had previous experience with that stimulus. This has been shown for judgment of faces, architecture, artworks and body movements. In contrast, other evidence suggests that this relationship can also work in the inverse direction, at least in the domain of watching dance. Specifically, it has been shown that in certain contexts, people derive greater pleasure from watching unfamiliar movements they ...

  15. Stroke survivors' views and experiences on impact of visual impairment.

    Science.gov (United States)

    Rowe, Fiona J

    2017-09-01

    We sought to determine stroke survivors' views on impact of stroke-related visual impairment to quality of life. Stroke survivors with visual impairment, more than 1 year post stroke onset, were recruited. Semistructured biographical narrative interviews were audio-recorded and transcribed verbatim. A thematic approach to analysis of the qualitative data was adopted. Transcripts were systematically coded using NVivo10 software. Thirty-five stroke survivors were interviewed across the UK: 16 females, 19 males; aged 20-75 years at stroke onset. Five qualitative themes emerged: "Formal care," "Symptoms and self," "Adaptations," "Daily life," and "Information." Where visual problems existed, they were often not immediately recognized as part of the stroke syndrome and attributed to other causes such as migraine. Many participants did not receive early vision assessment or treatment for their visual problems. Visual problems included visual field loss, double vision, and perceptual problems. Impact of visual problems included loss in confidence, being a burden to others, increased collisions/accidents, and fear of falling. They made many self-identified adaptations to compensate for visual problems: magnifiers, large print, increased lighting, use of white sticks. There was a consistent lack of support and provision of information about visual problems. Poststroke visual impairment causes considerable impact to daily life which could be substantially improved by simple measures including early formal visual assessment, management and advice on adaptive strategies and self-management options. Improved education about poststroke visual impairment for the public and clinicians could aid earlier diagnosis of visual impairments.

  16. Three Mile Island Cleanup: experiences, waste disposal, and environmental impact

    International Nuclear Information System (INIS)

    King, L.J.; Opelka, J.H.

    1982-01-01

    These papers were presented in a two-session symposium during the American Institute of Chemical Engineers 1981 Summer National meeting in Detroit, Michigan, August 16-19, 1981. The cleanup activities described included the venting of the gases, mostly krypton-85, from the reactor containment building and several entries of personnel into the containment building to determine the physical conditions and the levels of radiation and radioactive contamination. Results of the latest process development tests of the flowsheet for the submerged Demineralizer Water Treatment System for decontaminating the water in the containment building were presented. The status of existing knowledge of radiation effects on ion exchange materials used in radioactive waste management were reviewed. A program to demonstrate incorporation of the loaded zeolite into a glass as a final waste form was also described. The generation, classification, treatment, and disposal of solid waste forms resulting from the cleanup were discussed with special consideration of the ion exchange media used for cleanup of liquids with relatively high radionuclide concentrations. The radiological, socioeconomic, and psychological impacts of the cleanup were evaluated. This work formed the basis for the recent issuance by the NRC of a programmatic environmental impact statement relative to decontamination and disposal of the radioactive wastes resulting from the accidents

  17. Ndt Characterization of Boron Carbide for Ballistic Applications

    Science.gov (United States)

    Liaptsis, D.; Cooper, I.; Ludford, N.; Gunner, A.; Williams, Mike; Willis, David

    2011-06-01

    Boron Carbide (B4C) is widely used to provide ballistic protection in challenging service environments. This work was carried out to develop non-destructive testing (NDT) for B4C characterization. Deliberate flaws were introduced within the B4C tiles during manufacturing. An experimental program was undertaken to determine the best method to detect defects in ceramic tiles and material characterization. Ultrasonic characterization of the material was found to be able to detect both density variation and defects within the material.

  18. Star-grain rocket motor - nonsteady internal ballistics

    Energy Technology Data Exchange (ETDEWEB)

    Loncaric, S.; Greatrix, D.R.; Fawaz, Z. [Ryerson University, Dept. of Aerospace Engineering, Toronto (Canada)

    2004-01-01

    The nonsteady internal ballistics of a star-grain solid-propellant rocket motor are investigated through a numerical simulation model that incorporates both the internal flow and surrounding structure. The effects of structural vibration on burning rate augmentation and wave development in nonsteady operation are demonstrated. The amount of damping plays a role in influencing the predicted axial combustion instability symptoms of the motor. The variation in oscillation frequencies about a given star grain section periphery, and along the grain with different levels of burn-back, also influences the means by which the local acceleration drives the combustion and flow behaviour. (authors)

  19. Thermodynamic Bounds on Precision in Ballistic Multiterminal Transport

    Science.gov (United States)

    Brandner, Kay; Hanazato, Taro; Saito, Keiji

    2018-03-01

    For classical ballistic transport in a multiterminal geometry, we derive a universal trade-off relation between total dissipation and the precision, at which particles are extracted from individual reservoirs. Remarkably, this bound becomes significantly weaker in the presence of a magnetic field breaking time-reversal symmetry. By working out an explicit model for chiral transport enforced by a strong magnetic field, we show that our bounds are tight. Beyond the classical regime, we find that, in quantum systems far from equilibrium, the correlated exchange of particles makes it possible to exponentially reduce the thermodynamic cost of precision.

  20. Quantum transport through ballistic chaotic cavities: a statistical approach

    International Nuclear Information System (INIS)

    Mello, P.A.

    1998-01-01

    The problem of quantum chaotic scattering is addressed by means of a statistical model for the scattering matrix. The model, introduced in the past in the context of nuclear physics, describes the problem in terms of a prompt and an equilibrated component: it incorporates the average value of the scattering matrix to describe the prompt processes and satisfies the requirements of flux conservation, causality and ergodicity. The model is applied to the analysis of electronic transport through ballistic mesoscopic cavities: it describes well the results arising form the numerical solution of the Schroedinger equation for two-dimensional cavities. (Author)

  1. Impact of Gamification of Vision Tests on the User Experience.

    Science.gov (United States)

    Bodduluri, Lakshmi; Boon, Mei Ying; Ryan, Malcolm; Dain, Stephen J

    2017-08-01

    Gamification has been incorporated into vision tests and vision therapies in the expectation that it may increase the user experience and engagement with the task. The current study aimed to understand how gamification affects the user experience, specifically during the undertaking of psychophysical tasks designed to estimate vision thresholds (chromatic and achromatic contrast sensitivity). Three tablet computer-based games were developed with three levels of gaming elements. Game 1 was designed to be a simple clinical test (no gaming elements), game 2 was similar to game 1 but with added gaming elements (i.e., feedback, scores, and sounds), and game 3 was a complete game. Participants (N = 144, age: 9.9-42 years) played three games in random order. The user experience for each game was assessed using a Short Feedback Questionnaire. The median (interquartile range) fun level for the three games was 2.5 (1.6), 3.9 (1.7), and 2.5 (2.8), respectively. Overall, participants reported greater fun level and higher preparedness to play the game again for game 2 than games 1 and 3 (P < 0.05). There were significant positive correlations observed between fun level and preparedness to play the game again for all the games (p < 0.05). Engagement (assessed as completion rates) did not differ between the games. Gamified version (game 2) was preferred to the other two versions. Over the short term, the careful application of gaming elements to vision tests was found to increase the fun level of users, without affecting engagement with the vision test.

  2. Made in Denmark 2014 - Evaluation of Spectator Experience and Tourism Economic Impacts

    DEFF Research Database (Denmark)

    Toft, Henrik; Zahle Østergaard, Mads

    2015-01-01

    This report is a translation of the impact analysis of the golf tournament, Made in Denmark, which was held in August 2014. The content of the report is divided into two sub-parts. The first part is an analysis of the spectator experience and how well the experience of being at this event was ass...... was asssessed by the spectators. The second part is a tourism economic impact analysis which purpose is to analyse, evaluate and assess the economic impact this event had on the local area where it was held.......This report is a translation of the impact analysis of the golf tournament, Made in Denmark, which was held in August 2014. The content of the report is divided into two sub-parts. The first part is an analysis of the spectator experience and how well the experience of being at this event...

  3. Workplace experience of radiographers: impact of structural and interpersonal interventions

    Energy Technology Data Exchange (ETDEWEB)

    Kubik-Huch, R.A.; Roempler, M.; Weber, A. [Kantonsspital Baden, Institute of Radiology, Baden (Switzerland); Klaghofer, R.; Buddeberg-Fischer, B. [Zurich University Hospital, Department of Psychosocial Medicine, Zurich (Switzerland)

    2010-02-15

    Within the framework of organisational development, an assessment of the workplace experience of radiographers (RGs) was conducted. The aims of this study were to develop structural and interpersonal interventions and to prove their effectiveness and feasibility. A questionnaire consisting of work-related factors, e.g. time management and communication, and two validated instruments (Workplace Analysis Questionnaire, Effort-Reward Imbalance Scale) was distributed to all RGs (n = 33) at baseline (T1). Interventions were implemented and a follow-up survey (T2) was performed 18 months after the initial assessment. At T1, areas with highest dissatisfaction were communication and time management for ambulant patients (bad/very bad, 57% each). The interventions addressed adaptation of work plans, coaching in developing interpersonal and team leadership skills, and regular team meetings. The follow-up survey (T2) showed significantly improved communication and cooperation within the team and improved qualification opportunities, whereas no significant changes could be identified in time management and in the workplace-related scales 'effort' expended at work and 'reward' received in return for the effort. Motivating workplace experience is important for high-level service quality and for attracting well-qualified radiographers to work at a place and to stay in the team for a longer period. (orig.)

  4. Cyber Bullying and Traumatic Experiences: The Impact on Learning Disabilities

    Directory of Open Access Journals (Sweden)

    Agathi Stathopoulou

    2018-03-01

    Full Text Available The aim of our research is to investigate the effects of traumatic experiences that teens with learning disorders had to go through. The sample of our study is consisted of 160 high school students who were referred in a web line evaluation form, due to low school performance. The research tool that was used was ACHENBACH’s self-report questionnaire for children and teenagers and more specifically the subscales for anxiety-depression and depression-withdrawal. Frequencies, percentages of responses and means have been calculated. An analysis of variance (one way anova to assess the differences in the averages of students' responses to the variable "experiencing a traumatic event" was also performed. The results showed that there are significant differences in the level of statistical significance p <0,01 between the means of students who say they have experienced a traumatic event and those who report that they haven’t. Particularly decisive traumatic experience for the students' mentality seems to be the in-school violence received by students and the death of a loved one. Application features that have to do with the cyber bulling are also presented briefly. 

  5. Workplace experience of radiographers: impact of structural and interpersonal interventions

    International Nuclear Information System (INIS)

    Kubik-Huch, R.A.; Roempler, M.; Weber, A.; Klaghofer, R.; Buddeberg-Fischer, B.

    2010-01-01

    Within the framework of organisational development, an assessment of the workplace experience of radiographers (RGs) was conducted. The aims of this study were to develop structural and interpersonal interventions and to prove their effectiveness and feasibility. A questionnaire consisting of work-related factors, e.g. time management and communication, and two validated instruments (Workplace Analysis Questionnaire, Effort-Reward Imbalance Scale) was distributed to all RGs (n = 33) at baseline (T1). Interventions were implemented and a follow-up survey (T2) was performed 18 months after the initial assessment. At T1, areas with highest dissatisfaction were communication and time management for ambulant patients (bad/very bad, 57% each). The interventions addressed adaptation of work plans, coaching in developing interpersonal and team leadership skills, and regular team meetings. The follow-up survey (T2) showed significantly improved communication and cooperation within the team and improved qualification opportunities, whereas no significant changes could be identified in time management and in the workplace-related scales 'effort' expended at work and 'reward' received in return for the effort. Motivating workplace experience is important for high-level service quality and for attracting well-qualified radiographers to work at a place and to stay in the team for a longer period. (orig.)

  6. Preliminary comparison of ballistic electron emission spectroscopy measurements on InAs quantum dots in a GaAs/AlGaAs heterostructure grown by MBE and MOVPE

    Czech Academy of Sciences Publication Activity Database

    Vaniš, Jan; Zelinka, Jiří; Malina, Václav; Henini, M.; Pangrác, Jiří; Melichar, Karel; Hulicius, Eduard; Šroubek, Filip; Walachová, Jarmila

    2009-01-01

    Roč. 40, č. 3 (2009), s. 496-498 ISSN 0026-2692 R&D Projects: GA ČR GA202/05/0242 Institutional research plan: CEZ:AV0Z20670512; CEZ:AV0Z10100521; CEZ:AV0Z10750506 Keywords : quantum dots * ballistic transport * semiconductor heterojunction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.778, year: 2009

  7. Study of InAs quantum dots in AlGaAs/GaAs heterostructure by ballistic electron emission microscopy/spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Walachová, Jarmila; Zelinka, Jiří; Malina, Václav; Vaniš, Jan; Šroubek, Filip; Pangrác, Jiří; Melichar, Karel; Hulicius, Eduard

    2007-01-01

    Roč. 91, č. 4 (2007), 042110.1-042110.3 ISSN 0003-6951 R&D Projects: GA ČR GA202/05/0242 Institutional research plan: CEZ:AV0Z20670512; CEZ:AV0Z10750506; CEZ:AV0Z10100521 Keywords : quantum dots * ballistic transport * semiconductor heterojunctions Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.596, year: 2007

  8. Ballistic electron emission spectroscopy/microscopy of self-assembled InAs quantum dots of different sizes embedded in GaAs/AlGaAs heterostructure

    Czech Academy of Sciences Publication Activity Database

    Walachová, Jarmila; Zelinka, Jiří; Malina, Václav; Vaniš, Jan; Šroubek, Filip; Pangrác, Jiří; Melichar, Karel; Hulicius, Eduard

    2008-01-01

    Roč. 92, č. 12 (2008), 012101.1-012101.3 ISSN 0003-6951 R&D Projects: GA ČR GA202/05/0242 Institutional research plan: CEZ:AV0Z20670512; CEZ:AV0Z10750506; CEZ:AV0Z10100521 Keywords : quantum dots * ballistic transport * semiconductor heterojunctions Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.726, year: 2008

  9. Comparisons of Ballistic Trajectory Simulations Using Artillery Meteorological Messages Derived from Local Balloon Data and Battlescale Forecast Model Data for the 1998 SADARM IOT&E Firings

    Science.gov (United States)

    2001-11-01

    Evaluation ( IOT &E) firings that occurred during the summer of 1998 at Fort Greeley, Alaska. Due to the complex terrain and local wind conditions encountered...in the test area during the IOT &E, the Met study was proposed as a way to evaluate current and future artillery Met forecasting capabilities to improve...SADARM targeting accuracy. This report includes Ballistic trajectory simulation analyses using raw and forecast Met values and corresponding actual impact data front the IOT &E firings.

  10. Results of a Round Robin ballistic load sensing headform test series

    NARCIS (Netherlands)

    Philippens, M.A.G.; Anctil, B.; Markwardt, K.C.

    2014-01-01

    The majority of methods to assess the behind armour blunt trauma (BABT) risk for ballistic helmets is based on plastic deformable headforms. An alternative, the Ballistic Load Sensing Headform (BLSH) can record the dynamic contact force between helmet back face and the skull. Helmet BABT methods are

  11. Design of Orion Soil Impact Study using the Modern Design of Experiments

    Science.gov (United States)

    DeLoach, Richard

    2010-01-01

    Two conventional One Factor At a Time (OFAT) test matrices under consideration for an Orion Landing System subscale soil impact study are reviewed. Certain weaknesses in the designs, systemic to OFAT experiment designs generally, are identified. An alternative test matrix is proposed that is based in the Modern Design of Experiments (MDOE), which achieves certain synergies by combining the original two test matrices into one. The attendant resource savings are quantified and the impact on uncertainty is discussed.

  12. Ductile damage in Taylor and Rod-on-rod impact experiment

    Science.gov (United States)

    Iannitti, Gianluca; Ruggiero, Andrew; Bonora, Nicola; Gentile, Domenico

    2013-06-01

    At equivalent impact velocity, pressure in Taylor and ROR impact experiment is not the same and this reflects in the resulting condition for ductile damage development. In this work, finite element parametric simulation was performed to investigate pressure wave development as a function of material and target work hardening curve. Using the Bonora damage model, the impact velocity necessary for generating ductile damage in high purity copper was assessed. Taylor and ROR experiments were performed at different equivalent impact velocities and metallographic investigation were performed on impacted samples in order to validate damage model predictions. In addition, the effect of temperature on damage development was also investigated performing impact tests at different reference temperatures.

  13. 75 FR 78268 - Draft NIJ Selection and Application Guide to Ballistic-Resistant Body Armor for Law Enforcement...

    Science.gov (United States)

    2010-12-15

    ... of Justice Programs Draft NIJ Selection and Application Guide to Ballistic-Resistant Body Armor for... of Draft NIJ Selection and Application Guide to Ballistic-Resistant Body Armor for Law Enforcement... the general public the draft ``NIJ Selection and Application Guide to Ballistic-Resistant Body Armor...

  14. Can Building Design Impact Physical Activity? A Natural Experiment.

    Science.gov (United States)

    Eyler, Amy A; Hipp, Aaron; Valko, Cheryl Ann; Ramadas, Ramya; Zwald, Marissa

    2018-03-01

    Workplace design can impact workday physical activity (PA) and sedentary time. The purpose of this study was to evaluate PA behavior among university employees before and after moving into a new building. A pre-post, experimental versus control group study design was used. PA data were collected using surveys and accelerometers from university faculty and staff. Accelerometry was used to compare those moving into the new building (MOVERS) and those remaining in existing buildings (NONMOVERS) and from a control group (CONTROLS). Survey results showed increased self-reported PA for MOVERS and NONMOVERS. All 3 groups significantly increased in objectively collected daily energy expenditure and steps per day. The greatest steps per day increase was in CONTROLS (29.8%) compared with MOVERS (27.5%) and NONMOVERS (15.9%), but there were no significant differences between groups at pretest or posttest. Self-reported and objectively measured PA increased from pretest to posttest in all groups; thus, the increase cannot be attributed to the new building. Confounding factors may include contamination bias due to proximity of control site to experimental site and introduction of a university PA tracking contest during postdata collection. Methodology and results can inform future studies on best design practices for increasing PA.

  15. Civilian casualties of Iraqi ballistic missile attack to

    Directory of Open Access Journals (Sweden)

    Khaji Ali

    2012-06-01

    Full Text Available 【Abstract】Objective: To determine the pattern of causalities of Iraqi ballistic missile attacks on Tehran, the capital of Iran, during Iraq-Iran war. Methods: Data were extracted from the Army Staff Headquarters based on daily reports of Iranian army units during the war. Results: During 52 days, Tehran was stroked by 118 Al-Hussein missiles (a modified version of Scud missile. Eighty-six missiles landed in populated areas. During Iraqi missile attacks, 422 civilians died and 1 579 injured (4.9 deaths and 18.3 injuries per missile. During 52 days, 8.1 of the civilians died and 30.4 injured daily. Of the cases that died, 101 persons (24% were excluded due to the lack of information. Among the remainders, 179 (55.8% were male and 142 (44.2% were female. The mean age of the victims was 25.3 years±19.9 years. Our results show that the high accuracy of modified Scud missiles landed in crowded ar-eas is the major cause of high mortality in Tehran. The pres-ence of suitable warning system and shelters could reduce civilian casualties. Conclusion: The awareness and readiness of civilian defense forces, rescue services and all medical facilities for dealing with mass casualties caused by ballistic missile at-tacks are necessary. Key words: Mortality; War; Mass casualty incidents; Wounds and injuries

  16. The proliferation of ballistic missiles: an aggravating factor of crises

    International Nuclear Information System (INIS)

    Rousset, Valery

    2015-01-01

    After a brief recall of the history of the development of ballistic missiles from World War II, the author discusses the various uses of these missiles, on the one hand by major powers, and on the other hand by other countries like Israel, Pakistan and India, and also Egypt and Iraq. He recalls the uses of these missiles during regional conflicts (Scuds by Iraq) and then discusses the issue of proliferation of ballistic missiles. He notices that most of these weapons are present in the arsenal of major powers under the form of intercontinental missiles, intermediate range weapons or theatre weapons. On the Third World side, proliferation concerns short- and medium-range missiles produced from technology transfers or national programmes. Mobile systems are now present in all conflicts (notably Libya, Syria) and are now based on more advanced technologies for propellers as well as for control and guidance systems. In the last part, the author discusses the perspectives associated with these missiles which are a strong offensive weapon, and are also modernised to carry nuclear warheads or multiple warheads. These evolutions could put the western superiority into question again

  17. Cyberbullying among University Students: Gendered Experiences, Impacts, and Perspectives

    Directory of Open Access Journals (Sweden)

    Chantal Faucher

    2014-01-01

    Full Text Available Cyberbullying is an emerging issue in the context of higher education as information and communication technologies (ICT increasingly become part of daily life in university. This paper presents findings from 1925 student surveys from four Canadian universities. The overall findings are broken down to determine gender similarities and differences that exist between male and female respondents’ backgrounds, ICT usage, experiences with cyberbullying, opinions about the issue, and solutions to the problem. We also examine the continuities between these findings and those of earlier studies on cyberbullying among younger students. Our findings also suggest that gender differences, which do emerge, provide some support for each of the three theoretical frameworks considered for understanding this issue, that is, relational aggression, cognitive-affective deficits, and power and control. However, none of these three models offers a full explanation on its own. The study thus provides information about cyberbullying behaviour at the university level, which has the potential to inform the development of more appropriate policies and intervention programs/solutions to address the gendered nature of this behaviour.

  18. CAPTCHA: Impact on User Experience of Users with Learning Disabilities

    Directory of Open Access Journals (Sweden)

    Ruti Gafni

    2016-12-01

    Full Text Available CAPTCHA is one of the most common solutions to check if the user trying to enter a Website is a real person or an automated piece of software. This challenge-response test, implemented in many Internet Websites, emphasizes the gaps between accessibility and security on the Internet, as it poses an obstacle for the learning-impaired in the reading and comprehension of what is presented in the test. Various types of CAPTCHA tests have been developed in order to address accessibility and security issues. The objective of this study is to investigate how the differences between various CAPTCHA tests affect user experience among populations with and without learning disabilities. A questionnaire accompanied by experiencing five different tests was administered to 212 users, 60 of them with learning disabilities. Response rates for each test and levels of success were collected automatically. Findings suggest that users with learning disabilities have more difficulties in solving the tests, especially those with distorted texts, have more negative attitudes towards the CAPTCHA tests, but the response time has no statistical difference from users without learning disabilities. These insights can help to develop and implement solutions suitable for many users and especially for population with learning disabilities.

  19. Setting a New Research Agenda: Professional Migration Experiences and Their Impact on Family Well-Being

    Science.gov (United States)

    Dunlop, Ted

    2011-01-01

    In this article, the author talks about the growing pattern of migration experiences for professional people and the impact these have on the well-being of the family as a whole and individual family members who reside outside their home countries for prescribed periods of time. It is easy to argue that the experiences of such families are far…

  20. The Impact of Internet Experience and Attitude on Student Preference for Blended Learning

    Science.gov (United States)

    Alzahrani, Majed Gharmallah; O'Toole, John Mitchell

    2017-01-01

    The purpose of this study is to investigate student experience with the Internet, and their attitudes towards using it, in an attempt to determine the impact of these experiences and attitudes on their view of the implementation of blended learning. Data from 142 Saudi students at a leading university in Saudi Arabia were collected via an online…

  1. A Multidimensional Exploration of the Impact of International Experiences on Counselors' Cross-Cultural Awareness

    Science.gov (United States)

    Okech, Jane E. Atieno; DeVoe, Stephen

    2010-01-01

    Literature on international experiences highlights their significant impact on the development of cross-cultural knowledge and awareness. Using practical examples derived from literature on multiculturalism, the multifaceted dimensions of international experiences are critically reviewed as an essential process for counselors dedicated to…

  2. The Impact of Study Abroad Experiences on Vocational Identity among College Students

    Science.gov (United States)

    Kronholz, Julia F.; Osborn, Debra S.

    2016-01-01

    The purpose of this study was to determine preliminary findings regarding the effect of a study abroad experience on vocational identity and career decision-making as defined by Cognitive Information Processing (CIP) theory (Sampson et al., 2004). The results revealed that a study abroad experience significantly impacts college students'…

  3. Experience and lessons from health impact assessment for human rights impact assessment.

    Science.gov (United States)

    Salcito, Kendyl; Utzinger, Jürg; Krieger, Gary R; Wielga, Mark; Singer, Burton H; Winkler, Mirko S; Weiss, Mitchell G

    2015-09-16

    As globalisation has opened remote parts of the world to foreign investment, global leaders at the United Nations and beyond have called on multinational companies to foresee and mitigate negative impacts on the communities surrounding their overseas operations. This movement towards corporate impact assessment began with a push for environmental and social inquiries. It has been followed by demands for more detailed assessments, including health and human rights. In the policy world the two have been joined as a right-to-health impact assessment. In the corporate world, the right-to-health approach fulfils neither managers' need to comprehensively understand impacts of a project, nor rightsholders' need to know that the full suite of their human rights will be safe from violation. Despite the limitations of a right-to-health tool for companies, integration of health into human rights provides numerous potential benefits to companies and the communities they affect. Here, a detailed health analysis through the human rights lens is carried out, drawing on a case study from the United Republic of Tanzania. This paper examines the positive and negative health and human rights impacts of a corporate operation in a low-income setting, as viewed through the human rights lens, considering observations on the added value of the approach. It explores the relationship between health impact assessment (HIA) and human rights impact assessment (HRIA). First, it considers the ways in which HIA, as a study directly concerned with human welfare, is a more appropriate guide than environmental or social impact assessment for evaluating human rights impacts. Second, it considers the contributions HRIA can make to HIA, by viewing determinants of health not as direct versus indirect, but as interrelated.

  4. Experimenting with electromagnetism using augmented reality: Impact on flow student experience and educational effectiveness

    OpenAIRE

    Ibáñez Espiga, María Blanca; Di Serio, Angela; Villaran Molina, Diego; Delgado Kloos, Carlos

    2014-01-01

    Educational researchers have recognized Augmented Reality (AR) as a technology with great potential to impact affective and cognitive learning outcomes. However, very little work has been carried out to substantiate these claims. The purpose of this study was to assess to which extent an AR learning application affects learners' level of enjoyment and learning effectiveness. The study followed an experimental/control group design using the type of the application (AR-based, web-based) as inde...

  5. Modeling and numerical simulation of interior ballistic processes in a 120mm mortar system

    Science.gov (United States)

    Acharya, Ragini

    Numerical Simulation of interior ballistic processes in gun and mortar systems is a very difficult and interesting problem. The mathematical model for the physical processes in the mortar systems consists of a system of non-linear coupled partial differential equations, which also contain non-homogeneity in form of the source terms. This work includes the development of a three-dimensional mortar interior ballistic (3D-MIB) code for a 120mm mortar system and its stage-wise validation with multiple sets of experimental data. The 120mm mortar system consists of a flash tube contained within an ignition cartridge, tail-boom, fin region, charge increments containing granular propellants, and a projectile payload. The ignition cartridge discharges hot gas-phase products and unburned granular propellants into the mortar tube through vent-holes on its surface. In view of the complexity of interior ballistic processes in the mortar propulsion system, the overall problem was solved in a modular fashion, i.e., simulating each physical component of the mortar propulsion system separately. These modules were coupled together with appropriate initial and boundary conditions. The ignition cartridge and mortar tube contain nitrocellulose-based ball propellants. Therefore, the gas dynamical processes in the 120mm mortar system are two-phase, which were simulated by considering both phases as an interpenetrating continuum. Mass and energy fluxes from the flash tube into the granular bed of ignition cartridge were determined from a semi-empirical technique. For the tail-boom section, a transient one-dimensional two-phase compressible flow solver based on method of characteristics was developed. The mathematical model for the interior ballistic processes in the mortar tube posed an initial value problem with discontinuous initial conditions with the characteristics of the Riemann problem due to the discontinuity of the initial conditions. Therefore, the mortar tube model was solved

  6. Ductile damage in Taylor-anvil and rod-on-rod impact experiment

    International Nuclear Information System (INIS)

    Iannitti, G; Bonora, N; Ruggiero, A; Testa, G

    2014-01-01

    At equivalent impact velocity, pressure in Taylor and ROR impact experiment is not the same and this reflects in the resulting condition for ductile damage development. In this work, finite element parametric simulation was performed to investigate pressure wave development as a function of material and target work hardening curve. Using the Bonora damage model, the impact velocity necessary for generating ductile damage in high purity copper was assessed. Taylor and ROR experiments were performed at different equivalent impact velocities and metallographic investigation were performed on impacted samples in order to validate damage model predictions. Results seems to indicate that ROR configuration is more appropriate for 2damage model validation while the Taylor anvil is more suitable for strength model assessment.

  7. Ductile damage in Taylor-anvil and rod-on-rod impact experiment

    Science.gov (United States)

    Iannitti, G.; Bonora, N.; Ruggiero, A.; Testa, G.

    2014-05-01

    At equivalent impact velocity, pressure in Taylor and ROR impact experiment is not the same and this reflects in the resulting condition for ductile damage development. In this work, finite element parametric simulation was performed to investigate pressure wave development as a function of material and target work hardening curve. Using the Bonora damage model, the impact velocity necessary for generating ductile damage in high purity copper was assessed. Taylor and ROR experiments were performed at different equivalent impact velocities and metallographic investigation were performed on impacted samples in order to validate damage model predictions. Results seems to indicate that ROR configuration is more appropriate for 2damage model validation while the Taylor anvil is more suitable for strength model assessment.

  8. Understanding the Effects of Collisional Evolution and Spacecraft Impact Experiments on Comets and Asteroids

    Science.gov (United States)

    Lederer, S.M.; Jensen, E.A.; Fane, M.; Smith, D.C.; Holmes, J.; Keller, L.P.; Lindsay, S.S.; Wooden, D.H.; Whizin, A.; Cintala, M.J.; hide

    2017-01-01

    Comets and asteroids have endured impacts from other solar system bodies that result in outcomes ranging from catastrophic collisions to regolith evolution due to micrometeorid bombardment of the surface ices and refactory components. Experiments designed to better understand these relics of solar system formation have been conducted on Earth in a laboratory setting, as well as in space through, e.g., the Deep Impact Mission to Comet Tempel 1. Deep Impact fired a high-speed impactor into the roughly 6 km nucleus of the comet. The ejecta plume generated by the impact was studied by both spacecraft instrumentation and groundbased telescopes.

  9. Ballistic Analysis of Capability to Parry the Wind Load at Initial Flight Path of Promising Aircrafts

    Directory of Open Access Journals (Sweden)

    S. N. Ilukhin

    2015-01-01

    Full Text Available The article describes a new approach to solving the problem of parrying the negative impact of the random wind loads at the initial stage of aircraft flight. Based on applied research and many years of practice is proved the usefulness of measures to eliminate the deviations caused by the wind at initial flight path.The paper provides a theoretical justification and formulates the basic law of control to parry the product reversal under the action of random wind. Via example of a modified ballistic target the logic of the functioning of a promising technique for correcting orbital speed is clearly illustrated. This study analyses the influence of the wind load on the dispersion characteristics of the product impact points. To identify the qualitative picture of the process under study was examined flight of the aircraft in the vertical plane. In comparison with uncorrectable case, a trivial example of a mathematical model is used to have an initial assessment of the proposed technique effectiveness. As a determining parameter, was considered a changing angle of the aircraft attack during flight. Using authors-developed algorithms, significant reduction in the dispersion of the product impact points was revealed upon performed calculations, thus bearing evidence of using this method in promising aircrafts of the class under consideration.

  10. Adaptations in athletic performance after ballistic power versus strength training.

    Science.gov (United States)

    Cormie, Prue; McGuigan, Michael R; Newton, Robert U

    2010-08-01

    To determine whether the magnitude of improvement in athletic performance and the mechanisms driving these adaptations differ in relatively weak individuals exposed to either ballistic power training or heavy strength training. Relatively weak men (n = 24) who could perform the back squat with proficient technique were randomized into three groups: strength training (n = 8; ST), power training (n = 8; PT), or control (n = 8). Training involved three sessions per week for 10 wk in which subjects performed back squats with 75%-90% of one-repetition maximum (1RM; ST) or maximal-effort jump squats with 0%-30% 1RM (PT). Jump and sprint performances were assessed as well as measures of the force-velocity relationship, jumping mechanics, muscle architecture, and neural drive. Both experimental groups showed significant (P < or = 0.05) improvements in jump and sprint performances after training with no significant between-group differences evident in either jump (peak power: ST = 17.7% +/- 9.3%, PT = 17.6% +/- 4.5%) or sprint performance (40-m sprint: ST = 2.2% +/- 1.9%, PT = 3.6% +/- 2.3%). ST also displayed a significant increase in maximal strength that was significantly greater than the PT group (squat 1RM: ST = 31.2% +/- 11.3%, PT = 4.5% +/- 7.1%). The mechanisms driving these improvements included significant (P < or = 0.05) changes in the force-velocity relationship, jump mechanics, muscle architecture, and neural activation that showed a degree of specificity to the different training stimuli. Improvements in athletic performance were similar in relatively weak individuals exposed to either ballistic power training or heavy strength training for 10 wk. These performance improvements were mediated through neuromuscular adaptations specific to the training stimulus. The ability of strength training to render similar short-term improvements in athletic performance as ballistic power training, coupled with the potential long-term benefits of improved maximal strength

  11. Assessment and monitoring of ballistic and maximal upper-body strength qualities in athletes.

    Science.gov (United States)

    Young, Kieran P; Haff, G Gregory; Newton, Robert U; Gabbett, Tim J; Sheppard, Jeremy M

    2015-03-01

    To evaluate whether the dynamic strength index (DSI: ballistic peak force/isometric peak force) could be effectively used to guide specific training interventions and detect training-induced changes in maximal and ballistic strength. Twenty-four elite male athletes were assessed in the isometric bench press and a 45% 1-repetition-maximum (1RM) ballistic bench throw using a force plate and linear position transducer. The DSI was calculated using the peak force values obtained during the ballistic bench throw and isometric bench press. Athletes were then allocated into 2 groups as matched pairs based on their DSI and strength in the 1RM bench press. Over the 5 wk of training, athletes performed either high-load (80-100% 1RM) bench press or moderate-load (40-55% 1RM) ballistic bench throws. The DSI was sensitive to disparate training methods, with the bench-press group increasing isometric bench-press peak force (P=.035, 91% likely), and the ballistic-bench-throw group increasing bench-throw peak force to a greater extent (P≤.001, 83% likely). A significant increase (P≤.001, 93% likely) in the DSI was observed for both groups. The DSI can be used to guide specific training interventions and can detect training-induced changes in isometric bench-press and ballistic bench-throw peak force over periods as short as 5 wk.

  12. The impact of power differentials on the care experiences of older people.

    Science.gov (United States)

    Doyle, Susanna

    2014-01-01

    This study explored the lived experience of a small group of older people living in South East Queensland receiving community-based care while living in their own homes. In-depth unstructured interviews were used in this interpretive hermeneutic phenomenological study to encourage participants to raise experiences that held meaning for them as individuals. Many reported a range of experiences demonstrating active power differentials between themselves as recipients of care and their carers, and impacting on their sense of independence and autonomy. The experiences described provide guidance on how care services might better address the needs of older people, from their own perspective.

  13. Shot noise in a harmonically driven ballistic graphene transistor

    Science.gov (United States)

    Korniyenko, Y.; Shevtsov, O.; Löfwander, T.

    2017-04-01

    We study time-dependent electron transport and quantum noise in a ballistic graphene field effect transistor driven by an ac gate potential. The nonlinear response to the ac signal is computed through Floquet theory for scattering states and Landauer-Büttiker theory for charge current and its fluctuations. Photon-assisted excitation of a quasibound state in the top-gate barrier leads to resonances in transmission that strongly influence the noise properties. For strong doping of graphene under source and drain contacts, when electrons are transmitted through the channel via evanescent waves, the resonance leads to a substantial suppression of noise. The Fano factor is then reduced well below the pseudodiffusive value, F tunneling (total suppression of back-reflection) persists for perpendicular incidence also when the barrier is driven harmonically. Although the transmission is inelastic and distributed among sideband energies, a sum rule leads to total suppression of shot noise.

  14. Interference in ballistic motor learning - is motor interference really sensory?

    DEFF Research Database (Denmark)

    Lundbye-Jensen, Jesper; Petersen, Tue Hvass; Rothwell, John C

    Skill gained after a short period of practice in one motor task can be abolished if a second task is learned shortly afterwards. We hypothesised that interference requires the same circuits to be engaged in the two tasks and provoke competing processes of synaptic plasticity. To test this, subjects...... learned a ballistic ankle plantarflexion task. Interference was observed following subsequent learning of a precision tracking task with the same movement direction and agonist muscles, but not by learning involving the opposite movement and antagonist muscles or by voluntary agonist contractions that did...... not require learning. Repeated transcranial magnetic stimulation (rTMS) of corticospinal motor output at intensities below ankle movement threshold did not cause interference, whereas suprathreshold rTMS did. Furthermore, electrical stimulation of the peripheral nerve to the plantarflexors (but not extensors...

  15. Historical Review of the Correlation of Ballistic and Metallurgical Characteristics of Domestic Armor at Watertown Arsenal

    Science.gov (United States)

    1945-12-07

    by the early part of 1942, and since the beginning of 1943 fracture tests for steel soundness and fiber and V-notch Charpy tests were also employed...prior to ballistic testing . Later, for armor 6" and thicker, non-ballistic tests (hardness and V-notch Charpy ) were substituted for ballistics. Today it...conclusions were drawn: "Shock failures in 1-112" and 2" armor, subjected to the slug test , are largely attributable to either poor steel quality, low

  16. Theoretical Study on Adhesives Used in Ballistic Protection Structures and Transparent Armor

    Directory of Open Access Journals (Sweden)

    Alil Luminiţa-Cristina

    2015-06-01

    Full Text Available This article is a brief study conducted on adhesives currently used for manufacturing performance ballistic protection structures. The study landmarks several aspects, such as: types of connections available to achieve multilayer structures based on ceramics, metals and polymers; ways in which adhesives influence the ballistic performance of protective structures; analysis of various types of adhesives used in ballistic protection industry; general considerations in the selection of adhesives for certain types of armor and protective structures; considerations for characterizing, testing and modeling adhesives.

  17. Ballistic Resistance of Armored Passenger Vehicles: Test Protocols and Quality Methods

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey M. Lacy; Robert E. Polk

    2005-07-01

    This guide establishes a test methodology for determining the overall ballistic resistance of the passenger compartment of assembled nontactical armored passenger vehicles (APVs). Because ballistic testing of every piece of every component of an armored vehicle is impractical, if not impossible, this guide describes a testing scheme based on statistical sampling of exposed component surface areas. Results from the test of the sampled points are combined to form a test score that reflects the probability of ballistic penetration into the passenger compartment of the vehicle.

  18. Impact of Pre-Pharmacy Work Experience on Development of Professional Identity in Student Pharmacists.

    Science.gov (United States)

    Bloom, Timothy J; Smith, Jennifer D; Rich, Wesley

    2017-12-01

    Objective. To determine the benefit of pharmacy work experience on the development of student pharmacists' professional identity. Methods. Students in all four professional years were surveyed using a validated Professional Self-identity Questionnaire (PSIQ). They were also asked about pharmacy experience prior to matriculation and their performance on Drug Information tests given midway through the P1 year and at the beginning of the P3 year. PSIQ responses and test results were compared based on pharmacy experience. Results. The PSIQ was completed by 293 student pharmacists, for a 67% response rate, with 76% of respondents reporting pharmacy experience prior to matriculation. Statistically higher scores on responses to 6 of the 9 PSIQ Likert-type items were observed from students in the first professional year for those with pharmacy experience; however, only one item in the second year showed differences with none in the third and fourth years. No impact of experience was observed on Top 100 or Top 300 grades. Conclusion. Pre-matriculation pharmacy experience may increase development of professional identity early in the student experience but may have little impact on academic readiness. Schools and colleges of pharmacy hoping to recruit students with an early sense of professional identity should consider adding such experience to their admissions requirements.

  19. The Czech Republic – impacts of and experience with EU membership

    Directory of Open Access Journals (Sweden)

    Ivo ŠLOSARČÍK

    2011-12-01

    Full Text Available This paper analyses the impact of the post-accession experience of the Czech Republic in the years 2004-2011. In particular, it focuses on the integration into the EU internal market, preparation for Eurozone accession, transfers from the EU budget and the formulation of the EU energy policy. In each policy area, both the impact of the existing EU regulatory framework and Czech preferences for its reforms are covered. The last section of the paper (chapter 6 describes the Czech institutional adaptation to the EU membership, in particular the 2009 Czech presidency experience.

  20. Constitutive equations of a ballistic steel alloy as a function of temperature

    Science.gov (United States)

    Berkovic, L.; Chabotier, A.; Coghe, F.; Rabet, L.

    2012-08-01

    In the present work, dynamic tests have been performed on a new ballistic steel alloy by means of split Hopkinson pressure bars (SHPB). The impact behavior was investigated for strain rates ranging from 1000 to 2500 s-1, and temperatures in the range from - 196 to 300∘C. A robotized sample device was developed for transferring the sample from the heating or cooling device to the position between the bars. Simulations of the temperature evolution and its distribution in the specimen were performed using the finite element method. Measurements with thermocouples added inside the sample were carried out in order to validate the FEM simulations. The results show that a thermal gradient is present inside the sample; the average temperature loss during the manipulation of the sample is evaluated. In a last stage, optimal material constants for different constitutive models (Johnson-Cook, Zerilli-Amstrong, Cowper-Symonds) has been computed by fitting, in a least square sense, the numerical and experimental stress-strain curves. They have been implemented in a hydrocode for validation using a simple impact problem: an adapted projectile geometry with a truncated nose (.50 calibre fragment simulating projectiles) was fired directly against an armor plate. The parameters of the selected strength and failure models were determined. There is a good correspondence between the experimental and computed results. Nevertheless, an improved failure model is necessary to get satisfactory computed residual projectile velocities.

  1. Constitutive equations of a ballistic steel alloy as a function of temperature

    Directory of Open Access Journals (Sweden)

    Coghe F.

    2012-08-01

    Full Text Available In the present work, dynamic tests have been performed on a new ballistic steel alloy by means of split Hopkinson pressure bars (SHPB. The impact behavior was investigated for strain rates ranging from 1000 to 2500 s−1, and temperatures in the range from − 196 to 300∘C. A robotized sample device was developed for transferring the sample from the heating or cooling device to the position between the bars. Simulations of the temperature evolution and its distribution in the specimen were performed using the finite element method. Measurements with thermocouples added inside the sample were carried out in order to validate the FEM simulations. The results show that a thermal gradient is present inside the sample; the average temperature loss during the manipulation of the sample is evaluated. In a last stage, optimal material constants for different constitutive models (Johnson-Cook, Zerilli-Amstrong, Cowper-Symonds has been computed by fitting, in a least square sense, the numerical and experimental stress-strain curves. They have been implemented in a hydrocode for validation using a simple impact problem: an adapted projectile geometry with a truncated nose (.50 calibre fragment simulating projectiles was fired directly against an armor plate. The parameters of the selected strength and failure models were determined. There is a good correspondence between the experimental and computed results. Nevertheless, an improved failure model is necessary to get satisfactory computed residual projectile velocities.

  2. Dynamic and impact contact mechanics of geologic materials: Grain-scale experiments and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Cole, David M.; Hopkins, Mark A.; Ketcham, Stephen A. [Engineer Research and Development Center - Cold Regions Research and Engineering Laboratory, 72 Lyme Rd., Hanover, NH 03755 (United States)

    2013-06-18

    High fidelity treatments of the generation and propagation of seismic waves in naturally occurring granular materials is becoming more practical given recent advancements in our ability to model complex particle shapes and their mechanical interaction. Of particular interest are the grain-scale processes that are activated by impact events and the characteristics of force transmission through grain contacts. To address this issue, we have developed a physics based approach that involves laboratory experiments to quantify the dynamic contact and impact behavior of granular materials and incorporation of the observed behavior indiscrete element models. The dynamic experiments do not involve particle damage and emphasis is placed on measured values of contact stiffness and frictional loss. The normal stiffness observed in dynamic contact experiments at low frequencies (e.g., 10 Hz) are shown to be in good agreement with quasistatic experiments on quartz sand. The results of impact experiments - which involve moderate to extensive levels of particle damage - are presented for several types of naturally occurring granular materials (several quartz sands, magnesite and calcium carbonate ooids). Implementation of the experimental findings in discrete element models is discussed and the results of impact simulations involving up to 5 Multiplication-Sign 105 grains are presented.

  3. Effect of Bainitic Microstructure on Ballistic Performance of Armour Steel Weld Metal Using Developed High Ni-Coated Electrode

    Science.gov (United States)

    Pramanick, A. K.; Das, H.; Reddy, G. M.; Ghosh, M.; Nandy, S.; Pal, T. K.

    2018-04-01

    Welding of armour steel has gained significant importance during the past few years as recent civilian and military requirements demand weld metal properties matching with base metal having good ballistic performance along with high strength and toughness at - 40 °C as per specification. The challenge of armour steel welding therefore lies in controlling the weld metal composition which is strongly dependent on welding electrode/consumables, resulting in desired weld microstructure consisting of lower bainite along with retained austenite. The performance of butt-welded armour steel joints produced by the developed electrodes was evaluated using tensile testing, ballistic testing, impact toughness at room temperature and subzero temperature. Microstructures of weld metals are exclusively characterized by x-ray diffraction technique, scanning electron microscope and transmission electron microscopy with selected area diffraction pattern. Experimental results show that weld metal with relatively lower carbon, higher manganese and lower nickel content was attributed to lower bainite with film type of retained austenite may be considered as a most covetable microstructure for armour steel weld metal.

  4. Impacts of a Southern Indiana Summer Camp: Adult Reflections on Childhood Experiences

    OpenAIRE

    Colin L. Snider; James R. Farmer

    2017-01-01

    Scholars have well documented the impact on youth of attending a residential summer camp. Quantitative studies, generally consisting of pre/post assessments, have found positive outcomes related to self-esteem, self-efficacy, hard skills, and social skills. We explored the long-term outcomes of the camp experience through adult recollections of the camp experience. Participants’ interviews provided four primary, emergent themes: self growth, affinity for nature, life skills, and relationship....

  5. The Impact of Customer Experience Toward Customer Satisfaction and Loyalty of Ciputra World Surabaya

    OpenAIRE

    Chandra, Silvana

    2014-01-01

    Ciputra World Surabaya is facing a tense competition, especially with the upcoming new shopping malls. Author believes that customer satisfaction and loyalty is the ultimate solutions to maintain the visitors traffic, which can be achieved by encouraging customer experience. The research succeeds to gather 142 respondents using simple random sampling method. Thus, by applying the Path Analysis with Regression, it is able to prove that customer experience has significant impact towa...

  6. Land use impacts of rapid transit: implications of recent experience. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Knight, R.L.; Trygg, L.L.

    1977-08-01

    Evidence of land use impacts of recent major rapid transit improvements are reviewed and conclusions drawn concerning the extent and nature of such impacts and the conditions under which they have occurred. Transit improvements studied are primarily post-World War II in origin. American and Canadian examples are stressed, although European experience is teated briefly. Virtually all major modern American and Canadian rapid transit investments are included, covering conventional rapid rail, commuter rail, light rail and bus/busway. In addition to conclusions on general patterns of land use impact and causes, research recommendations and Federal policy implications are drawn.

  7. IMPULSE Highlights for recent experiments at the Advanced Photon Source (2/9-2/18 2014)

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Brian J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-03-18

    This report is a presentation, with slides noting, Over 40 experiments were completed during this run using X-ray imaging on the IMPULSE system at Sector 32 IDB; Summary of new experiments: Idealized sphere compaction – Capture progression of dynamic densification through an idealized system on 0.500 mm borosilicate glass spheres (Slide 1); Detonator and EBW Imaging Experiments on IMPULSE – First time HE was intentionally detonated at APS (Slide 2); Spall and high strain rate crack nucleation/propagation in PMMA – PCI data is providing new and unique insights for model validation (Slide 3); Fiber composite for armor applications was studied under ballistic impact of Dyneema (Collaboration with Army Research Laboratory) (Slide 4). Summary of on-going experiments; Crack propagation in vitreous carbon – observed crack motion and caustic; Jet formation experiments on large grain cerium to examine phase dependent strength; Ballistic impact of Comp-B and TNT to examine thermo-mechanical response in-situ with various penetrator geometries to vary shear concentration. Other efforts: IMPULSE system moved and installed in Sector 35 (DCS). This includes the 4-frame X-ray detection system, 4- channel PDV, and other gun diagnostics; New remotely operated mobile IMPULSE structure in fabrication – to be delivered to APS in April; 4 Mini-VISAR Systems and 4-channel PDV installed in DCS instrumentation room with all associated diagnostics.

  8. A qualitative analysis of the experience and impact of killing in hand-to-hand combat.

    Science.gov (United States)

    Jensen, Peter R; Simpson, Duncan

    2014-08-01

    A growing body of research suggests that killing during military combat is closely associated with posttraumatic stress disorder (PTSD), as well as a number of other adverse mental health related conditions (e.g., dissociative experiences, violent behavior, functional impairment). This article provides first-person perspectives on the experiences and impact of killing by service members with the goal of expanding our understanding of the impact of taking a life during war. In audio-recorded phenomenological interviews, 9 service members described their experiences and the subsequent impact of killing during hand-to-hand combat. A description, supported by participant quotations, was constructed to represent the participants' experiences. Results suggest the experience and aftermath of taking a life in hand-to-hand combat was disturbing, psychologically stressful, and necessitated some form of coping after the event. Service members who killed in hand-to-hand combat viewed their actions as necessary to preserve their life and that killing in hand-to-hand combat was more emotionally taxing than killing by shooting. Our findings may help to improve providers' understanding of service members' first-person experiences of killing in hand-to-hand combat and thus provide the basis for the development of a connected and genuine relationship with such military clients. Copyright © 2014 International Society for Traumatic Stress Studies.

  9. Modeling of ballistic and trapping effects on the collection efficiency of holes and electrons separately for a planar mercuric iodide detector (HgI2

    Directory of Open Access Journals (Sweden)

    Cedric E. Beogo

    2016-07-01

    Full Text Available For the room temperature nuclear detector application, signal created in the detector depends not only to the energy of the incident photon but also to the position of the interaction. This can bring an incomplete charge collection caused by a deep-trapping or a ballistic deficit of charge carrier. Many scientists used to demonstrate their impact on the global efficiency of the charge collection. Here we show this effect, not globally but separately, according to the position where holes and electrons are created. It permits us to see the contribution of each kind of carrier in the signal formation. An analytical model of charge collection is developed firstly to take into account the deep-trapping only. Secondly, this model is improved adding the ballistic deficit effect. The deep-trapping contributes to reduce the efficiency of hole above all on thicker detector. In the other part, ballistic deficit reduce electron efficiency above all near anode in the negatively polarized detector.

  10. Investigating the Role of Collisions on Cometary Dust through High-Velocity Impact Experiments

    Science.gov (United States)

    Lederer, Susan M.; Cintala, M. J.; Olney, R. D.; Keller, L. P.; Nakamura-Messenger, K.

    2007-10-01

    The nebular theory of solar-system formation dictates that early in the Solar System's history, collisions between bodies occurred frequently and continue today. Collisions between small bodies have reworked the surface compositions and structures of cometary nuclei, though to an unknown degree. Here we present preliminary results from high-velocity impact experiments designed to investigate the role of collisional processing on the properties (e.g., shock-related, spectral, composition) of comets with emphasis on the evolution of primordial dust due to impacts. Analyses of the pre- and post-impacted materials were chosen to best allow interpretation of telescopic data of cometary dust, as well as allow direct comparison with comet dust samples from Stardust and IDPs believed to originate from comets. Impact experiments were conducted at the NASA Johnson Space Center Experimental Impact Laboratory using the Vertical Impact gun. Target materials were selected to reflect the bulk composition of Deep Impact target, Comet 9P/ Tempel 1 dust (Harker et al. 2005, Science 310; Lisse et al. 2006, Science 313), and Stardust target, Comet Wild 2 (Brownlee et al. 2006, Science 314). Magnesium-rich olivine (forsterite) and pyroxene (enstatite), diopside, pyrrhotite, and amorphous carbon were chosen to represent the comet dust. Targets were impacted by 3-mm ceramic and nylon projectiles at 2 km/s, which reflects typical impact speeds between objects in the Kuiper Belt. Analyses of the pre- and post-impacted materials will be presented, including a) infrared spectra, using a Fourier Transform Infrared Spectrometer (1.5 - 25 um), b) the structural/shock-induced effects of the dust, through Transmission Electron Microscope data, and c) compositional information via X-ray Diffraction lab studies. This study was made possible by a grant from Research Corporation.

  11. Ballistic Imaging in the Primary Breakup Region of Diesel Injector Sprays

    National Research Council Canada - National Science Library

    Linne, M. A; Parker, T. E

    2006-01-01

    ...) for single-shot imaging of the near-field primary breakup region of a diesel spray. Ballistic imaging is a non-intrusive optical measurement technique that produces line-of-sight integrated images...

  12. Ballistic Missile Defense: National Security and the High Frontier of Space.

    Science.gov (United States)

    Adragna, Steven P.

    1985-01-01

    Ballistic missile defense is discussed, and the rationale behind the proposal to place defensive weapons in space is examined. Strategic defense is a national security, political, and moral imperative. (RM)

  13. Small Business Innovation Research Program at the Ballistic Missile Defense Organization

    National Research Council Canada - National Science Library

    1995-01-01

    The audit objective was to determine whether the Ballistic Missile Defense Organization complied with legislation and DoD policy covering commercial potential requirements for Phase 1 of the SBIR program...

  14. Performance of Plain Woven Jute Fabric-Reinforced Polyester Matrix Composite in Multilayered Ballistic System

    Directory of Open Access Journals (Sweden)

    Sergio Neves Monteiro

    2018-02-01

    Full Text Available The ballistic performance of plain woven jute fabric-reinforced polyester matrix composites was investigated as the second layer in a multilayered armor system (MAS. Volume fractions of jute fabric, up to 30 vol %, were mixed with orthophthalic polyester to fabricate laminate composites. Ballistic tests were conducted using high velocity 7.62 mm ammunition. The depth of penetration caused by the bullet in a block of clay witness, simulating a human body, was used to evaluate the MAS ballistic performance according to the international standard. The fractured materials after tests were analyzed by scanning electron microscopy (SEM. The results indicated that jute fabric composites present a performance similar to that of the much stronger Kevlar™, which is an aramid fabric laminate, as MAS second layer with the same thickness. The mechanism of this similar ballistic behavior as well as the comparative advantages of the jute fabric composites over the Kevlar™ are discussed.

  15. Micro-Doppler Feature Extraction and Recognition Based on Netted Radar for Ballistic Targets

    Directory of Open Access Journals (Sweden)

    Feng Cun-qian

    2015-12-01

    Full Text Available This study examines the complexities of using netted radar to recognize and resolve ballistic midcourse targets. The application of micro-motion feature extraction to ballistic mid-course targets is analyzed, and the current status of application and research on micro-motion feature recognition is concluded for singlefunction radar networks such as low- and high-resolution imaging radar networks. Advantages and disadvantages of these networks are discussed with respect to target recognition. Hybrid-mode radar networks combine low- and high-resolution imaging radar and provide a specific reference frequency that is the basis for ballistic target recognition. Main research trends are discussed for hybrid-mode networks that apply micromotion feature extraction to ballistic mid-course targets.

  16. Women's experiences of victimizing sexualization, Part II: Community and longer term personal impacts.

    Science.gov (United States)

    Smith, S K

    1997-01-01

    This is the second of a two-part article describing the results of a qualitative study on women's experiences of victimizing sexualization. Ten adult women described their experiences of harmful learning about themselves as female and sexual. A four-part thematic description of women's experiences of victimizing sexualization was derived. This article reports on two of the major categories: community and cultural characteristics and longer term personal impacts. Findings of the study support the feminist position that the enactment of gender itself at social and cultural levels sometimes places women at risk for victimization.

  17. Unveiling Clues from Spacecraft Missions to Comets and Asteroids through Impact Experiments

    Science.gov (United States)

    Lederer, Susan M.; Jensen, Elizabeth; Fane, Michael; Smith, Douglas; Holmes, Jacob; Keller, Lindasy P.; Lindsay, Sean S.; Wooden, Diane H.; Whizin, Akbar; Cintala, Mark J.; hide

    2016-01-01

    The Deep Impact Spacecraft mission was the first to boldly face the challenge of impacting the surface of a comet, 9P/Tempel 1, to investigate surface and subsurface 'pristine' materials. The Stardust mission to Comet 81P/Wild 2 brought back an exciting surprise: shocked minerals which were likely altered during the comet's lifetime. Signatures of shock in meteorites also suggest that the violent past of the solar system has left our small bodies with signatures of impacts and collisions. These results have led to the question: How have impacts affected the evolutionary path taken by comets and asteroids, and what signatures can be observed? A future planetary mission to a near-Earth asteroid is proposing to take the next steps toward understanding small bodies through impacts. The mission would combine an ESA led AIM (Asteroid Impact Mission) with a JHU/APL led DART (Double Asteroid Redirect Mission) spacecraft to rendezvous with binary near-Earth asteroid 65803 Didymus (1996 G2). DART would impact the smaller asteroid, 'Didymoon' while AIM would characterize the impact and the larger Didymus asteroid. With these missions in mind, a suite of experiments have been conducted at the Experimental Impact Laboratory (EIL) at NASA Johnson Space Center to investigate the effects that collisions may have on comets and asteroids. With the new capability of the vertical gun to cool targets in the chamber through the use of a cold jacket fed by liquid nitrogen, the effects of target temperature have been the focus of recent studies. Mg-rich forsterite and enstatite (orthopyroxene), diopside (monoclinic pyroxene) and magnesite (Mg-rich carbonate) were impacted. Target temperatures ranged from 25 deg to -100 deg, monitored by connecting thermocouples to the target container. Impacted targets were analyzed with a Fourier Transform Infrared Spectrometer (FTIR) and Transmission Electron Microscope (TEM). Here we present the evidence for impact-induced shock in the minerals through

  18. Trident II (D-5) Sea Launched Ballistic Missile UGM 133A (Trident II Missile)

    Science.gov (United States)

    2015-12-01

    TRIDENT II (D5) Sea-Launched Ballistic Missile UGM 133A (TRIDENT II (D5) missile) developed an improved Submarine Launched Ballistic Missile with...The TRIDENT II (D5) missile’s increased payload allows the deterrent mission to be achieved with fewer submarines . Trident II Missile December 2015...needed for the cable builds, which extended the overall time required for build/test, and b) unplanned work was required during the Burn-In Console

  19. Forensic chemistry: perspective of new analytical methods applied to documentoscopy, ballistic and drugs of abuse

    OpenAIRE

    Romão, Wanderson; Schwab, Nicolas V; Bueno, Maria Izabel M. S; Sparrapan, Regina; Eberlin, Marcos N; Martiny, Andrea; Sabino, Bruno D; Maldaner, Adriano O

    2011-01-01

    In this review recent methods developed and applied to solve criminal occurences related to documentoscopy, ballistic and drugs of abuse are discussed. In documentoscopy, aging of ink writings, the sequence of line crossings and counterfeiting of documents are aspects to be solved with reproducible, fast and non-destructive methods. In ballistic, the industries are currently producing ''lead-free'' or ''nontoxic'' handgun ammunitions, so new methods of gunshot residues characterization are be...

  20. The role of contemporary ferrous and nonferrous materials in ballistic protection of military vehicles

    OpenAIRE

    Dimeski, Dimko; Srebrenkoska, Vineta

    2014-01-01

    Metallic armor is the most mature class of armor materials and is still widely used for ballistic protection today. Although the materials for metallic armor are highly developed, new and innovative metallic armor systems are being used to improve the ballistic protection (while reducing the weight) of various weapon systems. Historically, most metallic armor evolved from designing materials to meet structural or other requirements rather than from designing specifically for balli...

  1. Small Business Administration Section 8 (A) Support Services Contracts at the Ballistic Missile Defense Organization.

    Science.gov (United States)

    1994-12-30

    W.V.W.W/.*.’ OFFICE OF THE INSPECTOR GENERAL SMALL BUSINESS ADMINISTRATION SECTION 8(A) SUPPORT SERVICES CONTRACTS AT THE BALLISTIC MISSILE...ORGANIZATION DIRECTOR, DEFENSE LOGISTICS AGENCY SUBJECT: Audit Report on Small Business Administration Section 8(a) Support Services Contracts at the...Project No. 2CH-5031.01) SMALL BUSINESS ADMINISTRATION SECTION 8(A) SUPPORT SERVICES CONTRACTS AT THE BALLISTIC MISSILE DEFENSE ORGANIZATION

  2. Low-temperature ballistic transport in nanoscale epitaxial graphene cross junctions

    OpenAIRE

    Weingart, S.; Bock, C.; Kunze, U.; Speck, F.; Seyller, Th.; Ley, L.

    2009-01-01

    We report on the observation of inertial-ballistic transport in nanoscale cross junctions fabricated from epitaxial graphene grown on SiC(0001). Ballistic transport is indicated by a negative bend resistance of R12,43 ~ 170 ohm which is measured in a non-local, four-terminal configuration at 4.2 K and which vanishes as the temperature is increased above 80 K.

  3. Comparison of porcine thorax to gelatine blocks for wound ballistics studies

    OpenAIRE

    Mabbott, A.; Carr, D. J.; Champion, S.; Malbon, C.

    2016-01-01

    Tissue simulants are typically used in ballistic testing as substitutes for biological tissues. Many simulants have been used, with gelatine amongst the most common. While two concentrations of gelatine (10 and 20?%) have been used extensively, no agreed standard exists for the preparation of either. Comparison of ballistic damage produced in both concentrations is lacking. The damage produced in gelatine is also questioned, with regards to what it would mean for specific areas of living tiss...

  4. Characterizing the dynamic strength of materials for ballistic applications

    Science.gov (United States)

    Cazamias, James Ulysses

    We unambiguously verified the hypothesis that normal penetration in brittle materials may be represented as a bi-modal process. The first mode is governed by fundamental strength properties of the target, while the second mode is governed by the fracture kinetics. We investigated the failure response of glass under impact loading. We observed a drop in the failure wave velocity by a factor of 1/2 after unloading. While not unexpected, this drop had not been clearly observed previously. In contradiction to literature values, we observed a drop in sound speed behind the failure wave. Finally, despite the common perception that the failed material is comminuted, we observed a finite tensile strength. We proposed a new variant of the Taylor test using scaled rods to examine strain rate effects. For armor steel, we observed changes in strength greater than what would be expected from a logarithmic dependence of strength on strain rate although not enough to account for scale effects. For tungsten penetrators, we observed that smaller scale tungsten rods appeared to have more work hardening than the large scale rods which might account for scale effects. We examined the square Taylor impact problem. We showed that the square Taylor test is a new way to study shear localization under compressive-shear loading. We performed the first shock characterization of AlON. We observed that the bar impact experiment appears to differentiate between different thicknesses of ceramic tile in qualitative agreement with subscale and full scale penetration experiments. We present data supporting the lower yield strength estimate of 4.3 GPa for alumina. We performed the first bar impact characterization of AlON.

  5. The Perceived Impact of Peer Leadership Experiences on College Academic Performance

    Science.gov (United States)

    Skipper, Tracy L.; Keup, Jennifer R.

    2017-01-01

    Open-ended data from the 2009 National Survey of Peer Leaders were analyzed to explore the impact of peer leadership on academic performance. While most participants suggested the experience had no effect on academics, perceptions varied by role. Peer leaders in academic and community service roles described increased skills and understanding of…

  6. Quality Assurance and Its Impact from Higher Education Institutions' Perspectives: Methodological Approaches, Experiences and Expectations

    Science.gov (United States)

    Bejan, Stelian Andrei; Janatuinen, Tero; Jurvelin, Jouni; Klöpping, Susanne; Malinen, Heikki; Minke, Bernhard; Vacareanu, Radu

    2015-01-01

    This paper reports on methodological approaches, experiences and expectations referring to impact analysis of quality assurance from the perspective of three higher education institutions (students, teaching staff, quality managers) from Germany, Finland and Romania. The presentations of the three sample institutions focus on discussing the core…

  7. Impact of RET Teacher-Developed Curriculum Units on Classroom Experiences for Teachers and Students

    Science.gov (United States)

    Klein-Gardner, Stacy S.; Johnston, Megan E.; Benson, Lisa

    2012-01-01

    This phenomenological study examined the impact of Research Experiences for Teachers (RET) teacher-developed curriculum on teaching styles and strategies at two RET sites with common Legacy Cycle training. The study was conducted to assess and document program-specific and National Science Foundation (NSF) goals related to classroom practices and…

  8. Laboratory Experiment Investigating the Impact of Ocean Acidification on Calcareous Organisms

    Science.gov (United States)

    Perera, Alokya P.; Bopegedera, A. M. R. P.

    2014-01-01

    The increase in ocean acidity since preindustrial times may have deleterious consequences for marine organisms, particularly those with calcareous structures. We present a laboratory experiment to investigate this impact with general, introductory, environmental, and nonmajors chemistry students. For simplicity and homogeneity, calcite was…

  9. Deployable Camera (DCAM3) System for Observation of Hayabusa2 Impact Experiment

    Science.gov (United States)

    Sawada, Hirotaka; Ogawa, Kazunori; Shirai, Kei; Kimura, Shinichi; Hiromori, Yuichi; Mimasu, Yuya

    2017-07-01

    An asteroid exploration probe "Hayabusa2", that was developed by Japan Aerospace Exploration Agency (JAXA), was launched on December 3rd, 2014 to challenge complicated and accurate operations during the mission phase around the C-type asteroid 162137 Ryugu (1999 JU3) (Tsuda et al. in Acta Astron. 91:356-362, 2013). An impact experiment on a surface of the asteroid will be conducted using the Small Carry-on Impactor (SCI) system, which will be the world's first artificial crater creation experiment on asteroids (Saiki et al. in Proc. International Astronautical Congress, IAC-12.A3.4.8, 2012, Acta Astron. 84:227-236, 2013a; Proc. International Symposium on Space Technology and Science, 2013b). We developed a new micro Deployable CAMera (DCAM3) system for remote observations of the impact phenomenon applying our conventional DCAM technology that is one of the smallest probes in space missions and gained a great success in past Japanese mission IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun). DCAM3 is a miniaturized separable unit that contains two cameras and radio communication devices for transmission image data to the mothership "Hayabusa2", and it observes the impact experiment at an unsafe region in where the "Hayabusa2" is difficult to stay because of a risk of exploding and impacting debris hitting. In this paper, we report details of the DCAM3 system and development results as well as our mission plan for the DCAM3 observation during the SCI experiment.

  10. The Impacts of Type 1 Diabetes on the K-12 Educational Experience

    Science.gov (United States)

    McKerns-O'Donnell, Monica A.

    2012-01-01

    The purpose of this qualitative research study was to uncover the impacts that type 1 diabetes have on a child's or adolescent's school educational experience. The study used a phenomenological approach based upon the work of Moustakas (1994). Purposeful sampling was used to identify participants. The participant group was comprised of 10…

  11. The Impact of Simulation-Based Learning Experience on Critical Thinking Acquisition

    Science.gov (United States)

    Rome, Candice

    2012-01-01

    The purpose of this comparative experimental project was to compare the impact of simulation-based learning experiences to traditional clinical rotations on critical thinking acquisition of associate nursing students within a maternal-child course. Innovative pedagogies have been integrated in nursing programs to augment inadequate clinical…

  12. The impact of gender diversity on the performance of business teams: evidence from a field experiment

    NARCIS (Netherlands)

    Hoogendoorn, S.; Oosterbeek, H.; van Praag, M.

    2013-01-01

    This paper reports on a field experiment conducted to estimate the impact of the share of women in business teams on their performance. Teams consisting of undergraduate students in business studies start up a venture as part of their curriculum. We manipulated the gender composition of teams and

  13. The impact of gender diversity on the performance of business teams: evidence from a field experiment.

    NARCIS (Netherlands)

    Hoogendoorn, S.; Oosterbeek, H.; van Praag, M.

    This paper reports about a field experiment conducted to estimate the impact of the share of women in business teams on their performance. Teams consisting of under-graduate students in business studies start up a venture as part of their curriculum. We manipulated the gender composition of teams

  14. The impact of gender diversity on the performance of business teams: evidence from a field experiment

    NARCIS (Netherlands)

    Hoogendoorn, S.; Oosterbeek, H.; van Praag, M.

    This paper reports about a field experiment conducted to estimate the impact of the share of women in business teams on their performance. Teams consisting of undergraduate students in business studies start up a venture as part of their curriculum. We manipulated the gender composition of teams and

  15. Impact of Nursing Students' Free-Clinic Experiences on Subsequent Professional Nursing Practice

    Science.gov (United States)

    Bell, Christina Lynn

    2017-01-01

    Bachelors of Science Nursing students at a small liberal arts college in the upper Midwest volunteer with an instructor at a free clinic as part of their curriculum. This study's purpose was to identify the impact of nursing students' free-clinic experiences on their subsequent professional nursing practice and their ability to attend to: (a)…

  16. Assessing the Impact of Direct Experience on Individual Preferences and Attitudes for Electric Vehicles

    DEFF Research Database (Denmark)

    Jensen, Anders Fjendbo

    -choice alternative only in the SC experiment of the final survey. In both surveys the scenarios presented in the experiment are customized based on a relevant car purchase as indicated by each respondent. An in-depth descriptive analysis of the data clearly indicates that preferences for several attributes changed...... with real-life experience. Especially, the preference for driving range, which is a critical attribute for EVs, changes and becomes twice as important in wave 2 as compared to wave 1. As in previous studies, results show that environmental concern has a positive effect on the choice of EVs, but results......-life experience with the new technology and better understand how it affects their lives. The objective of this thesis is to investigate the extent to which direct experience with an EV affects individual preferences for specific EV characteristics and attitudes towards relevant topics and how this impacts market...

  17. Orientation Effects in Ballistic High-Strained P-type Si Nanowire FETs

    Directory of Open Access Journals (Sweden)

    Hong Yu

    2009-04-01

    Full Text Available In order to design and optimize high-sensitivity silicon nanowire-field-effect transistor (SiNW FET pressure sensors, this paper investigates the effects of channel orientations and the uniaxial stress on the ballistic hole transport properties of a strongly quantized SiNW FET placed near the high stress regions of the pressure sensors. A discrete stress-dependent six-band k.p method is used for subband structure calculation, coupled to a two-dimensional Poisson solver for electrostatics. A semi-classical ballistic FET model is then used to evaluate the ballistic current-voltage characteristics of SiNW FETs with and without strain. Our results presented here indicate that [110] is the optimum orientation for the p-type SiNW FETs and sensors. For the ultra-scaled 2.2 nm square SiNW, due to the limit of strong quantum confinement, the effect of the uniaxial stress on the magnitude of ballistic drive current is too small to be considered, except for the [100] orientation. However, for larger 5 nm square SiNW transistors with various transport orientations, the uniaxial tensile stress obviously alters the ballistic performance, while the uniaxial compressive stress slightly changes the ballistic hole current. Furthermore, the competition of injection velocity and carrier density related to the effective hole masses is found to play a critical role in determining the performance of the nanotransistors.

  18. Application of Super-Hydrophobic Coating for Enhanced Water Repellency of Ballistic Fabric

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Barton [ORNL; Rajic, Slobodan [ORNL; Hunter, Scott Robert [ORNL

    2014-10-01

    The objective of this work was to demonstrate that a superhydrophobic coating technology developed at Oak Ridge National Laboratory (ORNL) increases the water repellency of ballistic fabric beyond that provided by existing water repellency treatments. This increased water repellency has the potential to provide durable ballistic fabric for body armor without adding significant weight to the armor or significant manufacturing cost. Specimens of greige and scoured ballistic fabric were treated with a superhydrophobic coating and their weights and degree of water repellency were compared to specimens of untreated fabric. Treatment of both greige and scoured ballistic fabrics yielded highly water repellent fabrics. Our measurements of the water droplet contact angles gave values of approximately 150 , near the lower limit of 160 for superhydrophobic surfaces. The coatings increased the fabric weights by approximately 6%, an amount that is many times less than the estimated weight increase in a conventional treatment of ballistic fabric. The treated fabrics retained a significant amount of water repellency following a basic abrasion test, with water droplet contact angles decreasing by 14 to 23 . Microscopic analysis of the coating applied to woven fabrics indicated that the coating adhered equally well to fibers of greige and scoured yarns. Future evaluation of the superhydrophobic water repellent treatment will involve the manufacture of shoot packs of treated fabric for ballistic testing and provide an analysis of manufacturing scale-up and cost-to-benefit considerations.

  19. Acute effect of a ballistic and a static stretching exercise bout on flexibility and maximal strength.

    Science.gov (United States)

    Bacurau, Reury Frank Pereira; Monteiro, Gizele Assis; Ugrinowitsch, Carlos; Tricoli, Valmor; Cabral, Leonardo Ferreira; Aoki, Marcelo Saldanha

    2009-01-01

    Different stretching techniques have been used during warm-up routines. However, these routines may decrease force production. The purpose of this study was to compare the acute effect of a ballistic and a static stretching protocol on lower-limb maximal strength. Fourteen physically active women (169.3 +/- 8.2 cm; 64.9 +/- 5.9 kg; 23.1 +/- 3.6 years) performed three experimental sessions: a control session (estimation of 45 degrees leg press one-repetition maximum [1RM]), a ballistic session (20 minutes of ballistic stretch and 45 degrees leg press 1RM), and a static session (20 minutes of static stretch and 45 degrees leg press 1RM). Maximal strength decreased after static stretching (213.2 +/- 36.1 to 184.6 +/- 28.9 kg), but it was unaffected by ballistic stretching (208.4 +/- 34.8 kg). In addition, static stretching exercises produce a greater acute improvement in flexibility compared with ballistic stretching exercises. Consequently, static stretching may not be recommended before athletic events or physical activities that require high levels of force. On the other hand, ballistic stretching could be more appropriate because it seems less likely to decrease maximal strength.

  20. Have we underestimated the kinematic and kinetic benefits of non-ballistic motion?

    Science.gov (United States)

    Frost, David M; Cronin, John B; Newton, Robert U

    2008-09-01

    Explosive upper-body movements, with which the load is not thrown (non-ballistic), may comprise a phase during which forces are produced in opposition to the motion of the load. Thirty men completed three test sessions (free weight, ballistic, and pneumatic), each consisting of a one-repetition maximum (1-RM) and four explosive repetitions of a bench press at six loads (15, 30, 45, 60, 75, and 90% 1-RM). The end of the lifting phase for the non-ballistic conditions (free weight and pneumatic) was defined by: the point of peak barbell displacement and the point at which the vertical force became negative (positive work). When analysed by peak displacement, the ballistic condition elicited significantly greater mean velocity, force, and power at loads of 15-60% 1-RM compared with the free weight condition. When the period of negative work was removed, the mean free weight velocity, force, and power at loads below 60% 1-RM increased. Consequently, the only differences between the free weight and ballistic conditions were found at loads of 15% and 30% 1-RM. Including a period of negative work may underestimate all kinematic and kinetic variables dependent on the time to, or position of, the end of the lifting phase, for non-ballistic efforts.

  1. Impact of sexual coercion on romantic experiences of adolescents and young adults.

    Science.gov (United States)

    Collibee, Charlene; Furman, Wyndol

    2014-10-01

    Little is known about the effect of sexual coercion on romantic relationship quality and dating experiences. The current study aimed to address this dearth in the literature and test the hypothesis that sexual coercion has a negative impact on victims' subsequent romantic experiences. Using a sample of 94 youth (44 males and 50 females), the current study addressed the impact of sexual coercion on romantic relationship quality and dating experiences. Tracking youth for 8.5 years (M age at Wave 1 = 15.10 years, SD = .49), the current study used piecewise growth curve modeling to account for shifts in the intercept and slope of romantic experiences following sexual coercion. Negative interactions immediately increased following coercion and continued to have an accelerated rate of growth (i.e., a slope change). Jealousy in romantic relationships increased in slope. Serious dating decelerated following the coercive incident. Results were largely consistent across gender and severity of the coercive incident. Contrary to hypotheses, relational support, relationship satisfaction, and casual dating did not significantly change following sexual coercion. Consistent with hypotheses, sexual coercion had a negative impact on romantic experiences. These findings have clinical implications for both prevention and intervention around sexual violence. In addition, the consistency of findings across gender and severity suggests that increased focus should be directed toward both male sexual coercion and less severe sexual coercion.

  2. Construction of climate change scenarios from transient climate change experiments for the IPCC impacts assessment

    International Nuclear Information System (INIS)

    Viner, D.; Hulme, M.; Raper, S.C.B.; Jones, P.D.

    1994-01-01

    This paper outlines the different methods which may be used for the construction of regional climate change scenarios. The main focus of the paper is the construction of global climate change scenarios from climate change experiments carried out using General Circulation Models (GCMS) An introduction to some GCM climate change experiments highlights the difference between model types and experiments (e.g., equilibrium or transient). The latest generation of climate change experiments has been performed using fully coupled ocean-atmosphere GCMS. These allow transient simulations of climate change to be performed with respect to a given greenhouse gas forcing scenario. There are, however, a number of problems with these simulations which pose difficulties for the construction of climate change scenarios for use in climate change impacts assessment. The characteristics of the transient climate change experiments which pose difficulties for the construction of climate change scenarios are discussed. Three examples of these problems are: different climate change experiments use different greenhouse gas concentration scenarios; the 'cold-start' problem makes it difficult to link future projections of climate change to a given calendar year; a drift of the climate is noticeable in the control simulations. In order to construct climate change scenarios for impacts assessment a method has therefore to be employed which addresses these problems. At present the climate modeling and climate change impacts communities are somewhat polarized in their approach to spatial scales. Current GCMs model the climate at resolutions larger than 2.5 x 3.75 degree, while the majority of impacts assessment studies are undertaken at scales below 50km (or 0.5 degree). This paper concludes by addressing the problems in bringing together these two different modeling perspectives by presenting a number of regional climate change scenarios. 35 refs., 8 figs., 2 tabs

  3. [Biomechanical-clinical interpretation of firearm wounds. General problems. VIII. Propedeutic ABC of terminal ballistics].

    Science.gov (United States)

    Marini, F; Dagradi, V; Radin, S; Mangiante, G; Carolo, F; Giarolli, M; Prati, G; Tenci, A; Della Giacoma, C; Massari, S

    1993-01-01

    The Authors, consistent with their aim to compare and contrast the two protagonists of bullet wounds, namely the bullet and its soft human target, delineating their respective profiles, strengths and weaknesses, feel obliged to dwell at some length on the most frequently pathogenetic regulation firearms. Up until the early twentieth century bullet wounds could be generically classified among the forms of open traumatism, but with the advent of high-speed bullets they have come to take on a unique profile of their own, setting against the old permanent cavity due to mechanical insult a new type of transitory ghost, the definition of which as a cavity would merely be an oversimplification in theoretical terms. Can we really attribute this somewhat privileged dimension to bullet wounds today or must we relegate them once again to the sphere of mechanical traumatisms, albeit with a new inflammatory key to their interpretation, making the most in this sense of the contribution provided by the speed of the bullet? The literature is abundant, but uncertain; we intend to attempt an answer to this tricky question in the following pages, devoted more properly to terminal ballistics. Undoubtedly, the new speeds have had a substantial impact on the wounds inflicted upon the soft target, but the streamlining of the jacket has modified and even offset the results, giving rise to the unexpectedly humanitarian bullet, later subject to reappraisal in military quarters as tactically more efficient, because it obliges the enemy to employ greater resources for recovering, assisting and healing the wounded. We can safely claim that ballistic science in the field of light or portable firearms is experiencing a contradiction between the speed of the bullet and the streamlining of the jacket which makes this speed possible, but which undermines the efficacy of the often unconfessable results. Short-barrelled firearms, which on account of their defensive role, the alibi of their

  4. A biologically inspired neural network controller for ballistic arm movements

    Directory of Open Access Journals (Sweden)

    Schmid Maurizio

    2007-09-01

    Full Text Available Abstract Background In humans, the implementation of multijoint tasks of the arm implies a highly complex integration of sensory information, sensorimotor transformations and motor planning. Computational models can be profitably used to better understand the mechanisms sub-serving motor control, thus providing useful perspectives and investigating different control hypotheses. To this purpose, the use of Artificial Neural Networks has been proposed to represent and interpret the movement of upper limb. In this paper, a neural network approach to the modelling of the motor control of a human arm during planar ballistic movements is presented. Methods The developed system is composed of three main computational blocks: 1 a parallel distributed learning scheme that aims at simulating the internal inverse model in the trajectory formation process; 2 a pulse generator, which is responsible for the creation of muscular synergies; and 3 a limb model based on two joints (two degrees of freedom and six muscle-like actuators, that can accommodate for the biomechanical parameters of the arm. The learning paradigm of the neural controller is based on a pure exploration of the working space with no feedback signal. Kinematics provided by the system have been compared with those obtained in literature from experimental data of humans. Results The model reproduces kinematics of arm movements, with bell-shaped wrist velocity profiles and approximately straight trajectories, and gives rise to the generation of synergies for the execution of movements. The model allows achieving amplitude and direction errors of respectively 0.52 cm and 0.2 radians. Curvature values are similar to those encountered in experimental measures with humans. The neural controller also manages environmental modifications such as the insertion of different force fields acting on the end-effector. Conclusion The proposed system has been shown to properly simulate the development of

  5. Developing a Ballistic Software Kit to Estimate Vehicle Characteristics at the Draft Design Stage

    Directory of Open Access Journals (Sweden)

    V. I. Maiorova

    2015-01-01

    Full Text Available The article describes a ballistic software kit to calculate a moving vehicle trajectory in atmosphere and space. Such software gives an opportunity to accelerate the acquisition of flying vehicle’s ballistic parameters at the stage of draft design. It contributes to improving collaboration efficiency between adjacent departments involved in the project. The developed software kit includes three different programs: Trajectory-LAND© (motion in atmosphere with possible correction of a trajectory, Trajectory-SPACE© (motion in the non-central gravity field with possible simulation of maneuvers, Trajectory-LAUNCH© (launch-vehicle’s insertion into the orbit with possible defining the impact points of separated stages. Each of the software concedes the addition of computational modules to use the solution results of the basic task. Implemented mathematical models permit to take into account the influence of main perturbations on the flying vehicle during the flight. For illustration purposes, the article gives some examples of using each of the programs and their block-diagrams.The developed software implements some algorithms, which allow attaining the convergence of numerical simulation of differential equations of motion. This problem arises, for example, while determining an attitude in case the stages have already separated from the launch vehicle. The mathematical conversion from Rodriguez-Hamilton parameters into Euler’s angles disables us to obtain reliable values of attitude angles due to the limitations for existing area of inverse trigonometric functions being used. Incorrect values of pitch lead to raw and roll channels divergences. Moreover, the mistakes in attitude determination lead to mistakes in obtained values of attack angle, which is included into the forms for aerodynamic forces and torques. As a result, the solution of system of differential equations is a failure when a flying vehicle enters the height of 30-35 km. The

  6. Ballistic Transport: After the Cassini Grand Finale, is there a Final Consensus on Ring Origin and Age?

    Science.gov (United States)

    Estrada, P. R.; Durisen, R. H.; Cuzzi, J. N.

    2017-12-01

    As the Cassini mission comes to its much anticipated end, somewhat befittingly to be immortalized and enshrined for all time within the gaseous confines of a planet named for the Greek god of time (Kronos), we find the time appropriate to return to the subject of ring age and origin. During Cassini's remarkable tenure, important measurements have been obtained that can help to elucidate and perhaps settle the debate once and for all on whether the rings are young or old. At the forefront lie the results of the Cassini Dust Analyzer (CDA) experiment which indicate that the range of the micrometeoroid flux at infinity for Saturn are comparable to the nominal value of the meteoroid flux value currently adopted for use in ballistic transport (BT) applications and models (Estrada et al., 2015, 2017). Moreover, the source of the micrometeoroid flux has been localized to the Edgeworth-Kuiper Belt (EKB) and is not cometary in origin as previously assumed (Altobelli et al., 2015). A major consequence of these measurements is that the EKB flux is much more gravitationally focused increasing the impact flux on the rings by a factor of ˜25 relative to cometary. This implies that the process of micrometeoroid bombardment and BT is likely even more influential in the rings' structural and compositional evolution over time. This measurement taken together with recent analysis of the bulk mass fraction of non-icy constituents (Zhang et al., 2017a,b) using Cassini radiometry data argue strongly for young rings. Another observation that will help to provide a constraint (though not absolute) is the pending measurement of the (B) ring mass. A high mass estimate as argued by some does not necessarily mean old rings, whereas a low mass ring would certainly imply as much. There are several factors that can offer insight on to the age of the rings from BT modeling, such as saturation of the ramp(s), color differences across the B-C (A-CD) boundaries, color differences across plateaus

  7. Laminated safety glass as an intermediate target: a wound ballistic study.

    Science.gov (United States)

    Kunz, Sebastian N; Zinka, Bettina M; Fieseler, Sybille; Graw, Matthias; Peschel, Oliver

    2012-09-01

    Various 9-mm ammunitions (A1, A4, A5, ST, GS, GSb, P.E.P., SeCa, HP, PTP/s, VM, McVG, DM41, PTP, SX2, PT, and MEN frangible) were tested regarding their velocity, energy, angle of impact, and potential wound channel after penetrating a car window at 30° and 90°. Test materials were gelatine, soap, and pig cadavers. The velocities of the projectiles were between c. 288 and 430 m/ses, the energy spread between 394 and 564 J. Handgun bullets fired through vehicular side window glass lose substantial energy reducing the effectiveness of the ammunition. This effect is greater when fired at an angle of 30° compared to 90°. At a shooting angle of 90°, none of the different projectiles showed remarkable differences considering its wound ballistic features. Accuracy is maintained at a 90° angle but seriously impaired at 30°. None of the examined ammunition complied with the demanded wound channel effectiveness of 30-60 J/cm. © 2012 American Academy of Forensic Sciences.

  8. THE IMPACT OF SOCIAL MEDIA ON THE TOURIST EXPERIENCE: TELLING YOUR STORY TO YOUR CONNECTED OTHERS

    Directory of Open Access Journals (Sweden)

    Burcu Selin Yilmaz

    2016-12-01

    Full Text Available The development of the Internet and improvements in information and communication technologies (ICTs allow consumers to share their opinions and experiences of products and services with other consumers through electronic word-of-mouth (eWOM, word-of-mouse communication. Tourism is one sector that has a very close relationship with the innovations in information technologies. Today, social media provide many opportunities for travellers to share their holiday experiences with their connected others. People share their opinions with connected others by sending e-mails, posting comments and feedback on websites and forums, publishing online blogs, and forming and joining communities on the Internet. Sharing their experiences with others contributes to the value of the experience and makes it more meaningful and memorable. In this study, following a theoretical discussion based on a review of the relevant literature, the researcher would like to demonstrate the role and importance of sharing the tourist experience with connected others in social media. By conducting structured interviews (online and offline with people who were chosen based on their holiday experience sharing habits, the contribution and role of storytelling in a tourism consumer’s holiday experience are explored. For new tourists, storytelling plays a serious role in addition to the holiday experience itself, and sharing experiences with connected others is seen as a vital tool for a fulfilling holiday experience. The results will demonstrate the contribution of storytelling to the tourist experience and provide a basis for further research on scale development for assessing the impact of storytelling on the tourist experience.

  9. Core-satellite supraparticles to ballistically stamp nanostructures on surfaces.

    Science.gov (United States)

    Oppmann, Maximilian; Miller, Franziska; Thürauf, Sandra; Groppe, Philipp; Prieschl, Johannes; Stauch, Claudia; Mandel, Karl

    2018-03-27

    Nanostructured surfaces are of great importance in a very wide range of fields. They can be obtained by imprint or deposition techniques. However, these are usually sophisticated to perform. Generally, it is not easy to equip an object/product with a nanostructure post manufacturing. Yet, it would be very beneficial to achieve a modification of an arbitrary surface with a nanostructure of choice at a later stage by an approach that is simple to perform without the need of sophisticated equipment or excessive treatment by physico-chemical methods. Herein, such a process is reported which combines two "old-fashioned" techniques, namely sandblasting and rubber-stamping, and translates them to the "nano-world". By creating core-satellite supraparticles via spray-drying, a ballistic core-satellite stamp particle system is obtained which can be used to easily transfer a wide range of nanoparticles to a great variety of surfaces to equip these with a nanostructure and subsequently advanced properties. These include water-repellant, anti-fouling or anti-dust surfaces. Moreover, it is also demonstrated that the approach can be used to manufacture well-defined nano-imprinted surfaces. Such surfaces showed an improved spreading behavior for aliphatic alcohols, thus rendering such surfaces for instance very susceptible for disinfectants. All in all, the simple technique described herein has a great potential for creating nanostructured surfaces on nearly any surface.

  10. Ballistic thermoelectric properties of nitrogenated holey graphene nanostructures

    Science.gov (United States)

    Cao, Wei; Xiao, Huaping; Ouyang, Tao; Zhong, Jianxin

    2017-11-01

    In this study, we theoretically investigate the ballistic thermoelectric performance of a new two-dimensional material, nitrogenated holey graphene (NHG), using nonequilibrium Green's function method. The calculations show that compared to graphene, such novel single atomic layer structure exhibits better thermoelectric performance. At room temperature, the stable hole (electron) thermoelectric figure of merit ( Z T ) could approach 0.75 (0.2) and 0.6 (0.2) for zigzag-edged (Z-NHGNRs) and armchair-edged NHGNRs (A-NHGNRs), respectively. To achieve better thermoelectric performance, the effect of geometric engineering (chevron-type nanoribbons and rhomboid quantum dot) on the electronic and phononic transport properties of Z-NHGNRs is further discussed. The results indicate that structure modulation is indeed a viable approach to enhance the thermoelectric properties (the figure of merit could exceed 1.5 and 1.3 for the chevron-type and rhomboid quantum dot system, respectively). On analyzing the transport properties, such improvement on the figure of merit is mainly attributed to the increased Seebeck coefficient and reduced thermal conductance (including both electronic and phononic contributions). Our findings presented in this paper qualify NHG as a promising thermoelectric material and provide theoretical guidance for fabricating the outstanding thermoelectric devices.

  11. Application of composite materials to impact-insensitive munitions

    Science.gov (United States)

    Neradka, Vincent F.; Chang, Yale; Grady, Joseph E.; Trowbridge, Daniel A.

    1992-01-01

    An approach is outlined for developing bullet-impact-insensitive munitions based on composite materials that provide rapid venting of the rocket-motor case. Impact experiments are conducted with test specimens of hybrid laminates of graphite/epoxy and epoxy reinforcing with woven glass fibers. The dynamic strain response and initial impact force are measured with strain gauges, and perforation damage is examined in the plates. The results show that impact damage can be designed by means of parametric variations of the fiber, matrix, and ply orientations. It is suggested that rocket-motor cases can be designed with composite materials to provide rapid venting during the failure mode. The experimental ballistic testing performed provides data that can be used comparatively with analytical data on composite materials.

  12. Eye movements and manual interception of ballistic trajectories: effects of law of motion perturbations and occlusions.

    Science.gov (United States)

    Delle Monache, Sergio; Lacquaniti, Francesco; Bosco, Gianfranco

    2015-02-01

    Manual interceptions are known to depend critically on integration of visual feedback information and experience-based predictions of the interceptive event. Within this framework, coupling between gaze and limb movements might also contribute to the interceptive outcome, since eye movements afford acquisition of high-resolution visual information. We investigated this issue by analyzing subjects' head-fixed oculomotor behavior during manual interceptions. Subjects moved a mouse cursor to intercept computer-generated ballistic trajectories either congruent with Earth's gravity or perturbed with weightlessness (0 g) or hypergravity (2 g) effects. In separate sessions, trajectories were either fully visible or occluded before interception to enforce visual prediction. Subjects' oculomotor behavior was classified in terms of amounts of time they gazed at different visual targets and of overall number of saccades. Then, by way of multivariate analyses, we assessed the following: (1) whether eye movement patterns depended on targets' laws of motion and occlusions; and (2) whether interceptive performance was related to the oculomotor behavior. First, we found that eye movement patterns depended significantly on targets' laws of motion and occlusion, suggesting predictive mechanisms. Second, subjects coupled differently oculomotor and interceptive behavior depending on whether targets were visible or occluded. With visible targets, subjects made smaller interceptive errors if they gazed longer at the mouse cursor. Instead, with occluded targets, they achieved better performance by increasing the target's tracking accuracy and by avoiding gaze shifts near interception, suggesting that precise ocular tracking provided better trajectory predictions for the interceptive response.

  13. THE IMPACT OF MARKETING EXPERIMENTS ON THE RELATIONSHIP BETWEEN SOFTWARE PRODUCERS AND THEIR RETAILERS

    Directory of Open Access Journals (Sweden)

    HERȚANU ANDREEA

    2013-07-01

    Full Text Available This paper presents the results of a marketing experiment done on the Romanian software market. The main purpose of this research is to determine how the marketing campaigns of software manufacturers can influence the decisions of software retailers. Through this marketing experimental research an evaluation and an analysis of the impact that marketing policies of software companies have on the retailers from all over the country is made. Three different marketing campaigns were proposed to three groups of software vendors from the most important cities of the country. The total number of software retailers included in this experiment is of 45, and the marketing campaigns proposed by the authors in this experiment refer to the Microsoft brand. Promotion strategies such as: sales promotion by encouraging sales force and promotional pricing or even the policy of partner relationship management have a great impact on three aspects regarding software retailers: loyalty, purchase and resale intention and attitude towards a brand. The results of the experiment show a high interest for the strategy of promotional pricing. The representatives of the software vendors have a positive orientation towards sales promotion by encouraging sales force. Regarding the influences of the manipulations used in the experiment, the greatest impact on the loyalty of the software vendors it has the strategy of promotional pricing. Also the policy of sales promotion by encouraging sales force has the biggest impact on the purchase and sale intention of the software retailers. All three manipulations have also an impact on the attitude towards a brand of the vendors, but the differences are too small to determine which of the proposed stimuli has a greater impact on this aspect. The results of the experiment may help and could have a great influence on the future marketing decisions of manufacturers regarding the strategies and marketing policies used on the Romanian

  14. Compression After Impact Experiments and Analysis on Honeycomb Core Sandwich Panels with Thin Facesheets

    Science.gov (United States)

    McQuigg, Thomas D.

    2011-01-01

    A better understanding of the effect of impact damage on composite structures is necessary to give the engineer an ability to design safe, efficient structures. Current composite structures suffer severe strength reduction under compressive loading conditions, due to even light damage, such as from low velocity impact. A review is undertaken to access the current state-of-development in the areas of experimental testing, and analysis methods. A set of experiments on honeycomb core sandwich panels, with thin woven fiberglass cloth facesheets, is described, which includes detailed instrumentation and unique observation techniques.

  15. MEASUREMENT OF THE CURRENT AND SYMMETRY OF THE IMPACT LINER ON THE NTLX EXPERIMENTS

    International Nuclear Information System (INIS)

    J. STOKES; J. PARKER; ET AL

    2001-01-01

    A series of four liner implosion experiments, denoted the Near Term Liner Experiments (NTLX) was recently conducted on the Shiva Star capacitor bank at the Air Force Research Laboratory (AFRL). Measurement of the driving currents in these experiments is required for post-shot analysis of the liner implosion and experiments conducted in the target cylinder. A Faraday rotation measurement was fielded on Shiva Star to measure the current and compare with the current measured by a Rogowski coil technique. The Faraday rotation technique measured the 16 MA currents in these experiments with better than 1% precision. In addition, six B-dot probes were fielded at equal angles around a circle in the powerflow channel outside the liner to measure the symmetry of the liner impact on the target cylinder. The B-dot probes measure the local I-dot, which has a jump when the liner impacts the target cylinder. A high-pass filter allows one to measure this jump more accurately. From the relative timing of the jump signals, the offset of the liner axis and the circularity of liner are inferred

  16. Inconsistency in 9 mm bullets: correlation of jacket thickness to post-impact geometry measured with non-destructive X-ray computed tomography.

    Science.gov (United States)

    Thornby, John; Landheer, Dirk; Williams, Tim; Barnes-Warden, Jane; Fenne, Paul; Norman, Danielle G; Attridge, Alex; Williams, Mark A

    2014-01-01

    Fundamental to any ballistic armour standard is the reference projectile to be defeated. Typically, for certification purposes, a consistent and symmetrical bullet geometry is assumed, however variations in bullet jacket dimensions can have far reaching consequences. Traditionally, characteristics and internal dimensions have been analysed by physically sectioning bullets--an approach which is of restricted scope and which precludes subsequent ballistic assessment. The use of a non-destructive X-ray computed tomography (CT) method has been demonstrated and validated (Kumar et al., 2011 [15]); the authors now apply this technique to correlate bullet impact response with jacket thickness variations. A set of 20 bullets (9 mm DM11) were selected for comparison and an image-based analysis method was employed to map jacket thickness and determine the centre of gravity of each specimen. Both intra- and inter-bullet variations were investigated, with thickness variations of the order of 200 μm commonly found along the length of all bullets and angular variations of up to 50 μm in some. The bullets were subsequently impacted against a rigid flat plate under controlled conditions (observed on a high-speed video camera) and the resulting deformed projectiles were re-analysed. The results of the experiments demonstrate a marked difference in ballistic performance between bullets from different manufacturers and an asymmetric thinning of the jacket is observed in regions of pre-impact weakness. The conclusions are relevant for future soft armour standards and provide important quantitative data for numerical model correlation and development. The implications of the findings of the work on the reliability and repeatability of the industry standard V50 ballistic test are also discussed. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  17. Effects of acute static, ballistic, and PNF stretching exercise on the muscle and tendon tissue properties.

    Science.gov (United States)

    Konrad, A; Stafilidis, S; Tilp, M

    2017-10-01

    The purpose of this study was to investigate the influence of a single static, ballistic, or proprioceptive neuromuscular facilitation (PNF) stretching exercise on the various muscle-tendon parameters of the lower leg and to detect possible differences in the effects between the methods. Volunteers (n = 122) were randomly divided into static, ballistic, and PNF stretching groups and a control group. Before and after the 4 × 30 s stretching intervention, we determined the maximum dorsiflexion range of motion (RoM) with the corresponding fascicle length and pennation angle of the gastrocnemius medialis. Passive resistive torque (PRT) and maximum voluntary contraction (MVC) were measured with a dynamometer. Observation of muscle-tendon junction (MTJ) displacement with ultrasound allowed us to determine the length changes in the tendon and muscle, respectively, and hence to calculate stiffness. Although RoM increased (static: +4.3%, ballistic: +4.5%, PNF: +3.5%), PRT (static: -11.4%, ballistic: -11.5%, PNF: -13,7%), muscle stiffness (static: -13.1%, ballistic: -20.3%, PNF: -20.2%), and muscle-tendon stiffness (static: -11.3%, ballistic: -10.5%, PNF: -13.7%) decreased significantly in all the stretching groups. Only in the PNF stretching group, the pennation angle in the stretched position (-4.2%) and plantar flexor MVC (-4.6%) decreased significantly. Multivariate analysis showed no clinically relevant difference between the stretching groups. The increase in RoM and the decrease in PRT and muscle-tendon stiffness could be explained by more compliant muscle tissue following a single static, ballistic, or PNF stretching exercise. © 2017 The Authors Scandinavian Journal of Medicine & Science In Sports Published by John Wiley & Sons Ltd.

  18. 3D topography measurements on correlation cells—a new approach to forensic ballistics identifications

    International Nuclear Information System (INIS)

    Song, John; Chu, Wei; Tong, Mingsi; Soons, Johannes

    2014-01-01

    Based on three-dimensional (3D) topography measurements on correlation cells, the National Institute of Standards and Technology (NIST) has developed the ‘NIST Ballistics Identification System (NBIS)’ aimed at accurate ballistics identifications and fast ballistics evidence searches. The 3D topographies are divided into arrays of correlation cells to identify ‘valid correlation areas’ and eliminate ‘invalid correlation areas’ from the matching and identification procedure. A ‘congruent matching cells’ (CMC)’ method using three types of identification parameters of the paired correlation cells (cross correlation function maximum CCF max , spatial registration position in x–y and registration angle θ) is used for high accuracy ballistics identifications. ‘Synchronous processing’ is proposed for correlating multiple cell pairs at the same time to increase the correlation speed. The proposed NBIS can be used for correlations of both geometrical topographies and optical intensity images. All the correlation parameters and algorithms are in the public domain and subject to open tests. An error rate reporting procedure has been developed that can greatly add to the scientific support for the firearm and toolmark identification specialty, and give confidence to the trier of fact in court proceedings. The NBIS is engineered to employ transparent identification parameters and criteria, statistical models and correlation algorithms. In this way, interoperability between different ballistics identification systems can be more easily achieved. This interoperability will make the NBIS suitable for ballistics identifications and evidence searches with large national databases, such as the National Integrated Ballistic Information Network in the United States. (paper)

  19. 3D topography measurements on correlation cells—a new approach to forensic ballistics identifications

    Science.gov (United States)

    Song, John; Chu, Wei; Tong, Mingsi; Soons, Johannes

    2014-06-01

    Based on three-dimensional (3D) topography measurements on correlation cells, the National Institute of Standards and Technology (NIST) has developed the ‘NIST Ballistics Identification System (NBIS)’ aimed at accurate ballistics identifications and fast ballistics evidence searches. The 3D topographies are divided into arrays of correlation cells to identify ‘valid correlation areas’ and eliminate ‘invalid correlation areas’ from the matching and identification procedure. A ‘congruent matching cells’ (CMC)’ method using three types of identification parameters of the paired correlation cells (cross correlation function maximum CCFmax, spatial registration position in x-y and registration angle θ) is used for high accuracy ballistics identifications. ‘Synchronous processing’ is proposed for correlating multiple cell pairs at the same time to increase the correlation speed. The proposed NBIS can be used for correlations of both geometrical topographies and optical intensity images. All the correlation parameters and algorithms are in the public domain and subject to open tests. An error rate reporting procedure has been developed that can greatly add to the scientific support for the firearm and toolmark identification specialty, and give confidence to the trier of fact in court proceedings. The NBIS is engineered to employ transparent identification parameters and criteria, statistical models and correlation algorithms. In this way, interoperability between different ballistics identification systems can be more easily achieved. This interoperability will make the NBIS suitable for ballistics identifications and evidence searches with large national databases, such as the National Integrated Ballistic Information Network in the United States.

  20. Impacts into porous asteroids

    Science.gov (United States)

    Housen, Kevin R.; Sweet, William J.; Holsapple, Keith A.

    2018-01-01

    Many small bodies in the solar system have bulk density well below the solid density of the constituent mineral grains in their meteorite counterparts. Those low-density bodies undoubtedly have significant porosity, which is a key factor that affects the formation of impact craters. This paper summarizes the results of lab experiments in which materials with porosity ranging from 43% to 96% were impacted at ∼1800 m/s. The experiments were performed on a geotechnical centrifuge, in order to reproduce the lithostatic overburden stress and ejecta ballistics that occur in large-scale cratering events on asteroids or planetary satellites. Experiments performed at various accelerations, up to 514G, simulate the outcomes of impacts at size scales up to several tens of km in diameter. Our experiments show that an impact into a highly porous cohesionless material generates a large ovoid-shaped cavity, due to crushing by the outgoing shock. The cavity opens up to form a transient crater that grows until the material flow is arrested by gravity. The cavity then collapses to form the final crater. During collapse, finely crushed material that lines the cavity wall is carried down and collected in a localized region below the final crater floor. At large simulated sizes (high accelerations), most of the crater volume is formed by compaction, because growth of the transient crater is quickly arrested. Nearly all ejected material falls back into the crater, leaving the crater without an ejecta blanket. We find that such compaction cratering and suppression of the ejecta blankets occur for large craters on porous bodies when the ratio of the lithostatic stress at one crater depth to the crush strength of the target exceeds ∼0.005. The results are used to identify small solar system bodies on which compaction cratering likely occurs. A model is developed that gives the crater size and ejecta mass that would result for a specified impact into a porous object.

  1. The Impact of Parental Involvement on a Structured Youth Program Experience: A Qualitative Inquiry

    Directory of Open Access Journals (Sweden)

    Mat D. Duerden

    2013-12-01

    Full Text Available Parental involvement is an often proposed, but rarely researched, key element of youth programs. Questions remain regarding the impact of parental involvement on program processes and outcomes. Qualitative data were collected over a one-year period with youth participants (n=46, parents (n=26, and teachers (n=5 associated with an international immersion/service learning program for adolescents. Three main research questions guided the data analysis: (1 what role does parental involvement play in the youths’ experience in the program; (2 how does parental involvement in the program influence the parent/child relationship; and (3 what role does parental involvement play in terms of the program’s long-term impact on the youth participants? Findings suggest a relationship between parental involvement in youth programs and improved parent/child communication, bonding, and perceptions of one another. Findings also suggest that having a common ground experience prolonged the experience’s positive post-participation effects.

  2. Predictions for impactor contamination on Ceres based on hypervelocity impact experiments

    Science.gov (United States)

    Daly, R. Terik; Schultz, Peter H.

    2015-10-01

    New experiments predict that Ceres should be extensively contaminated with meteoritic debris derived from the asteroid belt. All types of impactors likely contribute to the contamination. Ceres may accrete debris more efficiently if it is ice-rich because of enhanced projectile survival and retention in porous ice targets. Experiments indicate that if a silicate regolith lag protects subsurface ice, then some of the projectile should be injected into the regolith during high-angle impacts, thereby hiding part of the projectile component from view. If impacts excavate ice, sublimation will gradually concentrate projectile relics into a surficial lag. In contrast, if the near-surface lacks ice, then accreted meteoritic debris should be distributed throughout a vertically mixed regolith. High-resolution images may reveal pristine projectile relics lining some crater floors. Moreover, we predict that the surface of Ceres is not exclusively endogenic and may be dominated by delivered exogenic debris.

  3. Experience with breast cancer, pre-screening perceived susceptibility and the psychological impact of screening

    DEFF Research Database (Denmark)

    Absetz, Pilvikki; Aro, Arja R; Sutton, Stephen R

    2003-01-01

    This prospective study examined whether the psychological impact of organized mammography screening is influenced by women's pre-existing experience with breast cancer and perceived susceptibility (PS) to the disease. From a target population of 16,886, a random sample of women with a normal...... responded to the follow-ups. Psychological impact was measured as anxiety (STAI-S), depression (BDI), health-related concerns (IAS), and breast cancer-specific beliefs and concerns. Data was analyzed with repeated measures analyses of variance, with estimates of effect size based on Eta-squared. Women...... normal mammograms. Experience and PS did not influence responses to different screening findings. Of the finding groups, false positives experienced most adverse effects: their risk perception increased and they reported most post-screening breast cancer-specific concerns. Furthermore, they became more...

  4. Integrating impact assessment and conflict management in urban planning: Experiences from Finland

    International Nuclear Information System (INIS)

    Peltonen, Lasse; Sairinen, Rauno

    2010-01-01

    The article examines the interlinkages between recent developments in conflict management and impact assessment procedures in the context of urban planning in Finland. It sets out by introducing the fields of impact assessment and conflict mediation. It then proceeds to discuss the development of impact assessment practices and the status of conflict mediation in Finnish land use planning. The case of Korteniitty infill development plan in Jyvaeskylae is used to demonstrate how the Finnish planning system operates in conflict situations - and how social impact assessment can contribute to managing planning conflicts. The authors ask how the processes of impact assessment contribute to conflict management. Based on the Finnish experience, it is argued that social impact assessment of land use plans can contribute to conflict management, especially in the absence of institutionalised conflict mediation processes. In addition, SIA may acquire features of conflict mediation, depending on extent and intensity of stakeholder participation in the process, and the quality of linkages it between knowledge production and decision-making. Simultaneously, conflict mediation practices and theoretical insights can inform the application of SIA to help it address land use conflicts more consciously.

  5. Impact of a brief addiction medicine training experience on knowledge self-assessment among medical learners

    OpenAIRE

    Klimas, Jan; Ahamad, Keith; Fairgrieve, Kit; McLean, Mark; et al.

    2017-01-01

    Background: Implementation of evidence-based approaches to the treatment of various substance use disorders is needed to tackle the existing epidemic of substance use and related harms. Most clinicians, however, lack knowledge and practical experience with these approaches. Given this deficit, the authors examined the impact of an inpatient elective in addiction medicine amongst medical trainees on addiction-related knowledge and medical management. Methods: Trainees who completed an elective...

  6. The Impact of College Peers on Academic Performance: Evidence from a Natural Experiment in Chile

    OpenAIRE

    Díez-Amigo, Sandro

    2014-01-01

    First year students at the Pontificia Universidad Católica de Chile, one of the leading Chilean universities, are randomly assigned to their first semester college class groups. This paper takes advantage of this natural experiment in order to robustly estimate the impact of peer characteristics on undergraduate academic performance. The research hypothesis is that being assigned as a freshman to a group with more or less students from a same school, or from a given socioeconomic background, ...

  7. Determination of minimum impact parameter by modified touching spheres schemes for intermediate energy Coulomb excitation experiments

    International Nuclear Information System (INIS)

    Kumar, Rajiv; Sharma, Shagun; Singh, Pradeep; Kharab, Rajesh

    2016-01-01

    The energy-independent touching spheres schemes commonly used for the determination of the safe minimum value of the impact parameter for Coulomb excitation experiments are modified through the inclusion of an energy-dependent term. The touching spheres+3fm scheme after modification emerges out to be the best one while touching spheres+4fm scheme is found to be better in its unmodified form. (orig.)

  8. Critical review of Type B shipping container impact analyses: present research areas and substantiating experiments

    International Nuclear Information System (INIS)

    Counts, J.; Payne, J.B.

    1976-01-01

    Assumptions and limitations of a one-dimensional computer code for analyzing the dynamic response of Type B shipping containers subjected to a 9.14 m drop onto a rigid horizontal target are discussed. Some predicted acceleration time-histories are shown and, where possible, compared with existing experimental records. A new and more accurate mathematical model for impacting shipping containers and planned substantiating experiments are reviewed. Other projects in the ongoing research program are briefly noted

  9. Benthic disturbance and impact experiments in the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, R.; Nath, B.N.; Valsangkar, A.B.; Parthiban, G.; Sivakholundu, K.M.; Walker, G.A.

    part of the Indian Deep-Sea Environment Experiment (INDEX) to assess the poten-tial environmental impact of nodule mining,it was proposed to simulate a disturbance on the seafloor and to study its effects on the benthic ecosystem. For this purpose a... benthic disturberwas used during cruise 3B of RV Yuzhmorgeologiyaduring August 1997,in a preselected test sitein the Central Indian Ocean. This multidisciplinary study aims to assess the potential effects of such activities. The program is funded...

  10. Comparison of thoracic wall behavior in large animals and human cadavers submitted to an identical ballistic blunt thoracic trauma.

    Science.gov (United States)

    Prat, Nicolas; Rongieras, Frédéric; de Freminville, Humbert; Magnan, Pascal; Debord, Eric; Fusai, Thierry; Destombe, Casimir; Sarron, Jean-Claude; Voiglio, Eric J

    2012-10-10

    Several models of ballistic blunt thoracic trauma are available, including human cadavers and large animals. Each model has advantages and disadvantages regarding anatomy and physiology, but they have not been compared with identical ballistic aggression. To compare thoracic wall behavior in 40-kg pigs and human cadavers, the thorax of 12 human cadavers and 19 anesthetized pigs were impacted with two different projectiles at different speeds. On the thoracic wall, the peak acceleration, peak velocity, maximal compression, viscous criterion, and injury criteria (e.g. abbreviated injury scale and number of rib fractures) were recorded. The correlations between these motion and injury parameters and the blunt criterion were compared between the two groups. The bone mineral density of each subject was also measured. The peak acceleration, the peak velocity and the viscous criterion were significantly higher for the pigs. The AIS and the number of rib fractures were significantly higher for human cadavers. The bone mineral density was significantly higher for cadavers, but was, for the two groups, significantly lower than for 30-year-old human. The motion of the pig's thoracic wall is greater than that of the human cadaver, and the severity of the impact is always greater for human cadavers than for pigs. In addition, pig bone is more elastic and less brittle than older human cadaver bone. Due to the bone mineral density, the thoracic wall of human adults should be more rigid and more resistant than the thoracic wall of human cadavers or pigs. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  11. The Effectiveness of the Gesture-Based Learning System (GBLS and Its Impact on Learning Experience

    Directory of Open Access Journals (Sweden)

    Moamer Ali Shakroum

    2016-06-01

    Full Text Available Several studies and experiments have been conducted in recent years to examine the value and the advantage of using the Gesture-Based Learning System (GBLS.The investigation of the influence of the GBLS mode on the learning outcomes is still scarce. Most previous studies did not address more than one category of learning outcomes (cognitive, affective outcomes, etc. at the same time when used to understand the impact of GBLS. Moreover, none of these studies considered the difference in students’ characteristics such as learning styles and spatial abilities. Therefore, a comprehensive empirical research on the impact of the GBLS mode on learning outcomes is needed. The purpose of this paper is to fill in the gap and to investigate the effectiveness of the GBLS mode on learning using Technology Mediated Learning (TML models. This study revealed that the GBLS mode has greater positive impact on students’ learning outcomes (cognitive and affective outcomes when compared with other two learning modes that are classified as Computer Simulation Software Learning (CSSL mode and conventional learning mode. In addition, this study also found that the GBLS mode is capable of serving all students with different learning styles and spatial ability levels. The results of this study revealed that the GBLS mode outperformed the existing learning methods by providing a unique learning experience that considers the differences between students. The results have also shown that the Kinect user interface can create an interactive and an enjoyable learning experience.

  12. Diagnostic exome sequencing in children: A survey of parental understanding, experience and psychological impact.

    Science.gov (United States)

    Wynn, J; Ottman, R; Duong, J; Wilson, A L; Ahimaz, P; Martinez, J; Rabin, R; Rosen, E; Webster, R; Au, C; Cho, M T; Egan, C; Guzman, E; Primiano, M; Shaw, J E; Sisson, R; Klitzman, R L; Appelbaum, P S; Lichter-Konecki, U; Anyane-Yeboa, K; Iglesias, A; Chung, W K

    2017-12-20

    Clinical exome sequencing (CES) is increasingly being used as an effective diagnostic tool in the field of pediatric genetics. We sought to evaluate the parental experience, understanding and psychological impact of CES by conducting a survey study of English-speaking parents of children who had diagnostic CES. Parents of 192 unique patients participated. The parent's interpretation of the child's result agreed with the clinician's interpretation in 79% of cases, with more frequent discordance when the clinician's interpretation was uncertain. The majority (79%) reported no regret with the decision to have CES. Most (65%) reported complete satisfaction with the genetic counseling experience, and satisfaction was positively associated with years of genetic counselor (GC) experience. The psychological impact of CES was greatest for parents of children with positive results and for parents with anxiety or depression. The results of this study are important for helping clinicians prepare families for the possible results and variable psychological impact of CES. The frequency of parental misinterpretation of test results indicates the need for additional clarity in the communication of results. Finally, while the majority of patients were satisfied with their genetic counseling, satisfaction was lower for new GCs, suggesting a need for targeted GC training for genomic testing. This article is protected by copyright. All rights reserved.

  13. Unveiling clues from Spacecraft Missions to Comets and Asteroids through Impact Experiments

    Science.gov (United States)

    Lederer, Susan M.; Jensen, Elizabeth; Fane, Michael; Smith, Douglas; Holmes, Jacob; Keller, Lindsay P.; Lindsay, Sean S.; Wooden, Diane H.; Whizin, Akbar; Cintala, Mark J.; Zolensky, Michael

    2016-10-01

    The Deep Impact Spacecraft mission was the first to boldly face the challenge of impacting the surface of a comet, 9P/Tempel 1, to investigate surface and subsurface 'pristine' materials. The Stardust mission to Comet 81P/Wild 2 brought back an exciting surprise: shocked minerals which were likely altered during the comet's lifetime. Signatures of shock in meteorites also suggest that the violent past of the solar system has left our small bodies with signatures of impacts and collisions. These results have led to the question: How have impacts affected the evolutionary path taken by comets and asteroids, and what signatures can be observed?A future planetary mission to a near-Earth asteroid is proposing to take the next steps toward understanding small bodies through impacts. The mission would combine an ESA led AIM (Asteroid Impact Mission) with a JHU/APL led DART (Double Asteroid Redirect Mission) spacecraft to rendezvous with binary near-Earth asteroid 65803 Didymus (1996 G2). DART would impact the smaller asteroid, 'Didymoon' while AIM would characterize the impact and the larger Didymus asteroid.With these missions in mind, a suite of experiments have been conducted at the Experimental Impact Laboratory (EIL) at NASA Johnson Space Center to investigate the effects that collisions may have on comets and asteroids. With the new capability of the vertical gun to cool targets in the chamber through the use of a cold jacket fed by liquid nitrogen, the effects of target temperature have been the focus of recent studies. Mg-rich forsterite and enstatite (orthopyroxene), diopside (monoclinic pyroxene) and magnesite (Mg-rich carbonate) were impacted. Target temperatures ranged from 25°C to -100°C, monitored by connecting thermocouples to the target container. Impacted targets were analyzed with a Fourier Transform Infrared Spectrometer (FTIR) and Transmission Electron Microscope (TEM). Here we present the evidence for impact-induced shock in the minerals through

  14. The experiences, coping mechanisms, and impact of death and dying on palliative medicine specialists.

    Science.gov (United States)

    Zambrano, Sofia C; Chur-Hansen, Anna; Crawford, Gregory B

    2014-08-01

    Research on the experiences, coping mechanisms, and impact of death and dying on the lives of palliative medicine specialists is limited. Most research focuses on the multidisciplinary team or on nurses who work with the dying. Fewer studies consider medical professionals trained in palliative medicine. This study aimed to explore the experiences, coping mechanisms, and impact of death and dying on palliative medicine specialists when dealing with their patients at the end of life. A qualitative research approach guided the study, one-on-one interview data were analyzed thematically. A purposeful sampling technique was employed for participant recruitment. Seven palliative medicine specialists practicing in one city participated in open-ended, in-depth interviews. The analysis of participants' accounts identified three distinct themes. These were Being with the dying, Being affected by death, and dying and Adjusting to the impact of death and dying. This study further contributes to the understanding of the impact of death and dying on professionals who care for dying patients and their families. Despite the stressors and the potential for burnout and compassion fatigue, these participants employed strategies that enhanced meaning-making and emphasized the rewards of their work. However, the consequences of work stressors cannot be underestimated in the practice of palliative care.

  15. The Deep Impact Network Experiment Operations Center Monitor and Control System

    Science.gov (United States)

    Wang, Shin-Ywan (Cindy); Torgerson, J. Leigh; Schoolcraft, Joshua; Brenman, Yan

    2009-01-01

    The Interplanetary Overlay Network (ION) software at JPL is an implementation of Delay/Disruption Tolerant Networking (DTN) which has been proposed as an interplanetary protocol to support space communication. The JPL Deep Impact Network (DINET) is a technology development experiment intended to increase the technical readiness of the JPL implemented ION suite. The DINET Experiment Operations Center (EOC) developed by JPL's Protocol Technology Lab (PTL) was critical in accomplishing the experiment. EOC, containing all end nodes of simulated spaces and one administrative node, exercised publish and subscribe functions for payload data among all end nodes to verify the effectiveness of data exchange over ION protocol stacks. A Monitor and Control System was created and installed on the administrative node as a multi-tiered internet-based Web application to support the Deep Impact Network Experiment by allowing monitoring and analysis of the data delivery and statistics from ION. This Monitor and Control System includes the capability of receiving protocol status messages, classifying and storing status messages into a database from the ION simulation network, and providing web interfaces for viewing the live results in addition to interactive database queries.

  16. Coercive and legitimate authority impact tax honesty: evidence from behavioral and ERP experiments.

    Science.gov (United States)

    Gangl, Katharina; Pfabigan, Daniela M; Lamm, Claus; Kirchler, Erich; Hofmann, Eva

    2017-07-01

    Cooperation in social systems such as tax honesty is of central importance in our modern societies. However, we know little about cognitive and neural processes driving decisions to evade or pay taxes. This study focuses on the impact of perceived tax authority and examines the mental chronometry mirrored in ERP data allowing a deeper understanding about why humans cooperate in tax systems. We experimentally manipulated coercive and legitimate authority and studied its impact on cooperation and underlying cognitive (experiment 1, 2) and neuronal (experiment 2) processes. Experiment 1 showed that in a condition of coercive authority, tax payments are lower, decisions are faster and participants report more rational reasoning and enforced compliance, however, less voluntary cooperation than in a condition of legitimate authority. Experiment 2 confirmed most results, but did not find a difference in payments or self-reported rational reasoning. Moreover, legitimate authority led to heightened cognitive control (expressed by increased MFN amplitudes) and disrupted attention processing (expressed by decreased P300 amplitudes) compared to coercive authority. To conclude, the neuronal data surprisingly revealed that legitimate authority may led to higher decision conflict and thus to higher cognitive demands in tax decisions than coercive authority. © The Author (2017). Published by Oxford University Press.

  17. Impacts of a Southern Indiana Summer Camp: Adult Reflections on Childhood Experiences

    Directory of Open Access Journals (Sweden)

    Colin L. Snider

    2017-01-01

    Full Text Available Scholars have well documented the impact on youth of attending a residential summer camp. Quantitative studies, generally consisting of pre/post assessments, have found positive outcomes related to self-esteem, self-efficacy, hard skills, and social skills. We explored the long-term outcomes of the camp experience through adult recollections of the camp experience. Participants’ interviews provided four primary, emergent themes: self growth, affinity for nature, life skills, and relationship. Outcomes appear to stem from camper-counselor relationships and unstructured free time. This study highlights the lifelong benefits of the camp experience and suggests there is utility in collecting adult long-term recollections of childhood memories.

  18. Assesing the Impact of Direct Experience on Individual Preferences and Attitudes for Electric Vehicles

    DEFF Research Database (Denmark)

    Jensen, Anders Fjendbo

    of the final survey. In both surveys the scenarios presented in the experiment are customized based on a relevant car purchase as indicated by each respondent. An in-depth descriptive analysis of the data clearly indicates that preferences for several attributes changed between the two waves. In general the EV......, which is a critical attribute for EVs, changes and becomes twice as important in wave 2 compared to wave 1. As in previous studies, results show that environmental concern has a positive effect on the choice for EVs, but results indicate that this effect does not change with experience. Using...... the environment have an impact on the choice of EVs. However, all these studies assume that individuals have pre-defined preferences. EVs are emerging products that few people have experienced and preferences and attitudes might change as the market for new products expands and individuals acquire experience...

  19. Feed-forward motor control of ultrafast, ballistic movements.

    Science.gov (United States)

    Kagaya, K; Patek, S N

    2016-02-01

    To circumvent the limits of muscle, ultrafast movements achieve high power through the use of springs and latches. The time scale of these movements is too short for control through typical neuromuscular mechanisms, thus ultrafast movements are either invariant or controlled prior to movement. We tested whether mantis shrimp (Stomatopoda: Neogonodactylus bredini) vary their ultrafast smashing strikes and, if so, how this control is achieved prior to movement. We collected high-speed images of strike mechanics and electromyograms of the extensor and flexor muscles that control spring compression and latch release. During spring compression, lateral extensor and flexor units were co-activated. The strike initiated several milliseconds after the flexor units ceased, suggesting that flexor activity prevents spring release and determines the timing of strike initiation. We used linear mixed models and Akaike's information criterion to serially evaluate multiple hypotheses for control mechanisms. We found that variation in spring compression and strike angular velocity were statistically explained by spike activity of the extensor muscle. The results show that mantis shrimp can generate kinematically variable strikes and that their kinematics can be changed through adjustments to motor activity prior to the movement, thus supporting an upstream, central-nervous-system-based control of ultrafast movement. Based on these and other findings, we present a shishiodoshi model that illustrates alternative models of control in biological ballistic systems. The discovery of feed-forward control in mantis shrimp sets the stage for the assessment of targets, strategic variation in kinematics and the role of learning in ultrafast animals. © 2016. Published by The Company of Biologists Ltd.

  20. Injury representation against ballistic threats using three novel numerical models.

    Science.gov (United States)

    Breeze, Johno; Fryer, R; Pope, D; Clasper, J

    2017-06-01

    Injury modelling of ballistic threats is a valuable tool for informing policy on personal protective equipment and other injury mitigation methods. Currently, the Ministry of Defence (MoD) and Centre for Protection of National Infrastructure (CPNI) are focusing on the development of three interlinking numerical models, each of a different fidelity, to answer specific questions on current threats. High-fidelity models simulate the physical events most realistically, and will be used in the future to test the medical effectiveness of personal armour systems. They are however generally computationally intensive, slow running and much of the experimental data to base their algorithms on do not yet exist. Medium fidelity models, such as the personnel vulnerability simulation (PVS), generally use algorithms based on physical or engineering estimations of interaction. This enables a reasonable representation of reality and greatly speeds up runtime allowing full assessments of the entire body area to be undertaken. Low-fidelity models such as the human injury predictor (HIP) tool generally use simplistic algorithms to make injury predictions. Individual scenarios can be run very quickly and hence enable statistical casualty assessments of large groups, where significant uncertainty concerning the threat and affected population exist. HIP is used to simulate the blast and penetrative fragmentation effects of a terrorist detonation of an improvised explosive device within crowds of people in metropolitan environments. This paper describes the collaboration between MoD and CPNI using an example of all three fidelities of injury model and to highlight future areas of research that are required. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  1. Developmental framework to validate future designs of ballistic neck protection.

    Science.gov (United States)

    Breeze, J; Midwinter, M J; Pope, D; Porter, K; Hepper, A E; Clasper, J

    2013-01-01

    The number of neck injuries has increased during the war in Afghanistan, and they have become an appreciable source of mortality and long-term morbidity for UK servicemen. A three-dimensional numerical model of the neck is necessary to allow simulation of penetrating injury from explosive fragments so that the design of body armour can be optimal, and a framework is required to validate and describe the individual components of this program. An interdisciplinary consensus group consisting of military maxillofacial surgeons, and biomedical, physical, and material scientists was convened to generate the components of the framework, and as a result it incorporates the following components: analysis of deaths and long-term morbidity, assessment of critical cervical structures for incorporation into the model, characterisation of explosive fragments, evaluation of the material of which the body armour is made, and mapping of the entry sites of fragments. The resulting numerical model will simulate the wound tract produced by fragments of differing masses and velocities, and illustrate the effects of temporary cavities on cervical neurovascular structures. Using this framework, a new shirt to be worn under body armour that incorporates ballistic cervical protection has been developed for use in Afghanistan. New designs of the collar validated by human factors and assessment of coverage are currently being incorporated into early versions of the numerical model. The aim of this paper is to describe this developmental framework and provide an update on the current progress of its individual components. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  2. Australian Academic Librarians’ Experience of Evidence Based Practice Involves Empowering, Intuiting, Affirming, Connecting, Noticing, and Impacting

    Directory of Open Access Journals (Sweden)

    Joanne Marie Muellenbach

    2017-12-01

    Full Text Available A Review of: Miller, F., Partridge, H., Bruce, C., Yates, C., & Howlett, A. (2017. How academic librarians experience evidence-based practice: A grounded theory model. Library & Information Science Research, 39(2, 124-130. http://dx.doi.org/10.1016/j.lisr.2017.04.003 Abstract Objective – To explore and enhance the understanding of how Australian library and information science (LIS practitioners experience or understand evidence based practice (EBP within the context of their day-to-day professional work. Design – Constructivist grounded theory methodology. Setting – University libraries in Queensland, Australia. Subjects – 13 academic librarians. Methods – Researchers contacted academic librarians by email and invited each participant to take part in a 30-60 minute, semi-structured interview. They designed interview questions to allow participants to explain their process and experience of EBP. Main results – This study identified six categories of experience of EBP using a constructivist grounded theory analysis process. The categories are: Empowering; Intuiting; Affirming; Connecting; Noticing; and Impacting. Briefly, empowering includes being empowered, or empowering clients, colleagues, and institutions through improved practice or performance. Intuiting includes being intuitive, or using one’s own intuition, wisdom, and understanding, of colleagues and clients’ behaviours to solve problems and redesign services. Affirming includes being affirmed through sharing feedback and using affirmation to strengthen support for action. Connecting includes being connected, and building connections, with clients, colleagues, and institutions. Noticing includes being actively aware of, observing, and reflecting on clients, colleagues, and literature within and outside of one’s own university, and noticing patterns in data to inform decision-making. Impacting includes being impactful, or having a visible impact, on clients, colleagues

  3. Estimating the Global Agricultural Impact of Solar Radiation Management using Volcanic Eruptions as Natural Experiments

    Science.gov (United States)

    Proctor, J.; Hsiang, S. M.; Burney, J. A.; Burke, M.; Schlenker, W.

    2017-12-01

    Solar radiation management (SRM) is increasingly considered an option for managing global temperatures, yet the economic impacts of ameliorating climatic changes by scattering sunlight back to space remain largely unknown. Though SRM may increase crop yields by reducing heat stress, its impacts from concomitant changes in available sunlight have never been empirically estimated. Here we use the volcanic eruptions that inspired modern SRM proposals as natural experiments to provide the first estimates of how the stratospheric sulfate aerosols (SS) created by the eruptions of El Chichon and Pinatubo altered the quantity and quality of global sunlight, how those changes in sunlight impacted global crop yields, and the total effect that SS may have on yields in an SRM scenario when the climatic and sunlight effects are jointly considered. We find that the sunlight-mediated impact of SS on yields is negative for both C4 (maize) and C3 (soy, rice, wheat) crops. Applying our yield model to a geoengineering scenario using SS-based SRM from 2050-2069, we find that SRM damages due to scattering sunlight are roughly equal in magnitude to SRM benefits from cooling. This suggests that SRM - if deployed using SS similar to those emitted by the volcanic eruptions it seeks to mimic - would attenuate little of the damages from climate change to global agriculture on net. Our approach could be extended to study SRM impacts on other global systems, such as human health or ecosystem function.

  4. The impact of automation on pharmacy staff experience of workplace stressors.

    Science.gov (United States)

    James, K Lynette; Barlow, Dave; Bithell, Anne; Hiom, Sarah; Lord, Sue; Oakley, Pat; Pollard, Mike; Roberts, Dave; Way, Cheryl; Whittlesea, Cate

    2013-04-01

    Determine the effect of installing an original pack automated dispensing system (ADS) on staff experience of occupational stressors. Pharmacy staff in a National Health Service hospital in Wales, UK, were administered an anonymous occupational stressor questionnaire pre- (n = 45) and post-automation (n = 32). Survey responses pre- and post-automation were compared using Mann-Whitney U test. Statistical significance was P ≤ 0.05. Four focus groups were conducted (two groups of accredited checking technicians (ACTs) (group 1: n = 4; group 2: n = 6), one group of pharmacists (n = 17), and one group of technicians (n = 4) post-automation to explore staff experiences of occupational stressors. Focus group transcripts were analysed according to framework analysis. Survey response rate pre-automation was 78% (n = 35) and 49% (n = 16) post-automation. Automation had a positive impact on staff experience of stress (P = 0.023), illogical workload allocation (P = 0.004) and work-life balance (P = 0.05). All focus-group participants reported that automation had created a spacious working environment. Pharmacists and ACTs reported that automation had enabled the expansion of their roles. Technicians felt like 'production-line workers.' Robot malfunction was a source of stress. The findings suggest that automation had a positive impact on staff experience of stressors, improving working conditions and workload. Technicians reported that ADS devalued their skills. When installing ADS, pharmacy managers must consider the impact of automation on staff. Strategies to reduce stressors associated with automation include rotating staff activities and role expansions. © 2012 The Authors. IJPP © 2012 Royal Pharmaceutical Society.

  5. The impact of timetable changes on student achievement and learning experiences.

    Science.gov (United States)

    Reinke, Nicole B

    2018-03-01

    Many pre-registration nursing programs in Australia use distributive models of clinical placement whereby students attend placement on regular days each week of the teaching semester. The use of this model offers practical advantages by increasing the placement offerings, but reduces the weekdays available for students to attend on-campus classes. The impact of introducing this model on the delivery of on-campus classes has not been examined. The aim of this study was to explore the impact of delivering classes using a condensed weekly timetable on the academic achievement, learning experiences and approaches to learning of pre-registration Bachelor of Nursing Science students at an Australian regional university. This was a mixed methods study, including Likert-type and free text responses. Second-year students studying Human Pathophysiology and Pharmacology were invited to complete a questionnaire about their learning practices and experiences; student grades were obtained from official university records. The academic achievement of students learning under the condensed class schedule was approximately 7.5% lower than that achieved by cohorts prior to the timetable changes. This resulted in an additional 9% of the cohort failing the subject compared to previous cohorts. Many students reported that they did not prepare adequately for classes and that their learning experiences were negatively impacted by the condensed class timetable. The incorporation of a distributed model for clinical placements required major changes to the delivery of on-campus coursework classes and added to the semester workload for some Nursing Science students. These changes coincided with lower academic achievement by students learning Human Pathophysiology and Pharmacology and poorer quality learning experiences. The development of students' awareness of how they study and the effectiveness of their study practices may help them to develop self-regulated learning skills which will

  6. Localization and Ballistic Diffusion for the Tempered Fractional Brownian-Langevin Motion

    Science.gov (United States)

    Chen, Yao; Wang, Xudong; Deng, Weihua

    2017-10-01

    This paper discusses the tempered fractional Brownian motion (tfBm), its ergodicity, and the derivation of the corresponding Fokker-Planck equation. Then we introduce the generalized Langevin equation with the tempered fractional Gaussian noise for a free particle, called tempered fractional Langevin equation (tfLe). While the tfBm displays localization diffusion for the long time limit and for the short time its mean squared displacement (MSD) has the asymptotic form t^{2H}, we show that the asymptotic form of the MSD of the tfLe transits from t^2 (ballistic diffusion for short time) to t^{2-2H}, and then to t^2 (again ballistic diffusion for long time). On the other hand, the overdamped tfLe has the transition of the diffusion type from t^{2-2H} to t^2 (ballistic diffusion). The tfLe with harmonic potential is also considered.

  7. Effect of SiC addition to the characteristics of Al-11Zn-6.7Mg composite produced by squeeze casting for ballistic application

    Science.gov (United States)

    Adiputra, R. F.; Wijanarko, R.; Angela, I.; Sofyan, B. T.

    2018-01-01

    Aluminium composite material as an alternative to steel used in body of tactical vehicles has been studied. Addition of SiC was expected to have strengthening effect on the composite matrix therefore improving its ballistic performance. Composites of Al-11Zn-6.7Mg matrix and SiC strengthening particles with the fraction of 0, 10, and 15 vol. % were fabricated through squeeze casting process. Composite samples were then precipitation strengthened at 130 °C for 102 h to further improve their toughness. Final products were characterized by using chemical composition testing, optical microscopy, Scanning Electron Microscope – Energy Dispersive Spectroscopy (SEM-EDS) and quantitative metallography to calculate porosity, hardness test, impact test, and type III ballistic test in accordance with NIJ 0108.04 standard. The results showed that increase in SiC volume fraction from 0 to 10 and 15 vol. % managed to improve the hardness from 73 to 85 and 87 HRB, respectively, while on the other hand reduced the impact values from 12,278.69 to 11,290.35 and 9,924.54 J/m2. SEM-EDS observation confirmed the presence of Mg3Zn3Al2 intermetallic compound which formed during solidification and indicated the precipitation of MgZn2 precipitates during ageing. The ballistic testing demonstrated a promising result of the potential of Al-11Zn-6.7Mg composite strengthened by 15 vol. % SiC to withstand penetration of type III bullet (7.62 mm).

  8. Effects, experiences, and impact of stigma on patients with bipolar disorder

    Directory of Open Access Journals (Sweden)

    Mileva VR

    2013-01-01

    Full Text Available Viktoria R Mileva,1 Gustavo H Vázquez,2 Roumen Milev31Psychology, School of Natural Sciences, University of Stirling, Stirling, UK; 2Department of Neurosciences, University of Palermo, Buenos Aires, Argentina; 3Department of Psychiatry, Queen's University, Kingston, ON, CanadaBackground: Many people with mental illness experience stigma that has impacted their lives. In this study, we validated the Inventory of Stigmatizing Experiences (ISE as a tool to help quantify the stigma experienced by patients with bipolar disorder and its impact on their lives. The ISE has two components, ie, the Stigma Experiences Scale (SES and the Stigma Impact Scale (SIS, which were administered to a population of Argentinean patients with bipolar disorder. We characterized the differences between these two populations using the SES and SIS. Finally, we compared SES and SIS scores with those in a population of Canadian patients with bipolar disorder.Methods: The SES and SIS scales were administered to tertiary care patients with bipolar I and II disorder in Argentina (n = 178 and Canada (n = 214.Results: In this study, we validated both SES (Kuder–Richardson coefficient of reliability, 0.78 and SIS (Cronbach's alpha, 0.91 scales in a population of Argentinean patients with bipolar disorder. There were no significant differences in stigma between patients with bipolar I or II disorder on SES or SIS. However, over 50% of all respondents believed that the average person is afraid of those with mental illnesses, that stigma associated with mental illness has affected their quality of life, and that their self-esteem has suffered due to stigma. In comparison with the Canadian population, Argentinean participants scored lower on both the SES and SIS, which may be due to cultural differences or to differences in population characteristics.Conclusion: Stigma associated with mental illness is serious and pervasive. If we are to find successful strategies to mitigate

  9. Neoliberal Policies and their Impact on Public Health Education: Observations on the Venezuelan Experience

    Directory of Open Access Journals (Sweden)

    Oscar Feo

    2008-11-01

    Full Text Available This article discusses the impact of neoliberal policies on the training of specialists in Public Health and describes the Venezuelan experience. In Venezuela, like other countries of the American continent, Public Health Schools had been transformed from institutions under the direction of the Ministry of Health to a model in which training took place under market conditions. Education in Public Health became a private good for individual consumption, and schools, lacking official funding, survived by offering courses in a market that did not necessarily respond to a country’s health needs. The conclusion discusses the currrent Venezuelan experience, in which the State has resumed control of the training of specialists in public health, making it more democratic, and adoptng an educational model centered around practice and whose purpose is the mass training of leadership teams to bolster the National Public Health System. In order to comment on the impact of neoliberal policies on training in public health we must first briefly review the following themes: 1. Basic concepts such as neoliberalism, globalization, and health systems. 2. The impact of neoliberal reforms on health. 3. The Venezuelan situation: basic principles for the training of professionals and technicians in health within the framework of a model of independent and sovereign national development. 4. Final reflections: challenges for the coming years.

  10. The impacts of nature experience on human cognitive function and mental health.

    Science.gov (United States)

    Bratman, Gregory N; Hamilton, J Paul; Daily, Gretchen C

    2012-02-01

    Scholars spanning a variety of disciplines have studied the ways in which contact with natural environments may impact human well-being. We review the effects of such nature experience on human cognitive function and mental health, synthesizing work from environmental psychology, urban planning, the medical literature, and landscape aesthetics. We provide an overview of the prevailing explanatory theories of these effects, the ways in which exposure to nature has been considered, and the role that individuals' preferences for nature may play in the impact of the environment on psychological functioning. Drawing from the highly productive but disparate programs of research in this area, we conclude by proposing a system of categorization for different types of nature experience. We also outline key questions for future work, including further inquiry into which elements of the natural environment may have impacts on cognitive function and mental health; what the most effective type, duration, and frequency of contact may be; and what the possible neural mechanisms are that could be responsible for the documented effects. © 2012 New York Academy of Sciences.

  11. New insights into the properties of contrail cirrus and their impact on climate from airborne experiments

    Science.gov (United States)

    Voigt, Christiane; Schumann, Ulrich; Minikin, Andreas; Schlager, Hans; Anderson, Bruce

    2016-04-01

    Current growth rates in aviation demand a profound scientific data base of contrail cirrus properties in order to accurately assess their climate impact. In particular, the differentiation of contrail cirrus in natural cirrus fields is challenging. Direct observations of contrail cirrus throughout their life cycle are scarce and therefore limit our understanding of the climate effects from contrail cirrus. Here, we give new insights into the growth, life-cycle and climate impact from contrail cirrus based on results from suite of aircraft experiments. NASA's ACCESSII mission focused on the detection of aircraft emissions and initial contrail stages. Nascent contrails were detected at cruise altitudes at 100 m distance to the engine exit. Contrail growth to 10-min contrail age was investigated during DLR's CONCERT campaigns. Finally, the objective of the ML-CIRRUS experiment was to study the life cycle and climate impact of contrail cirrus. The contrail measurements are related to previous observations and discussed in the context of recent developments in contrail modeling. Highlights include the quantification of the effects of aircraft type on contrail microphysics, the analysis of ice particle shapes and the quantitative distinction of contrail cirrus and natural cirrus.

  12. Integral and local density of states of InAs quantum dots in GaAs/AlGaAs heterostructure observed by ballistic electron emission spectroscopy near one-electron ground state

    Czech Academy of Sciences Publication Activity Database

    Walachová, Jarmila; Zelinka, Jiří; Leshkov, Sergey; Šroubek, Filip; Pangrác, Jiří; Vaniš, Jan

    2013-01-01

    Roč. 48, č. 1 (2013), s. 61-65 ISSN 1386-9477 R&D Projects: GA ČR GPP102/11/P824; GA ČR GAP102/10/1201 Institutional research plan: CEZ:AV0Z10100521 Institutional support: RVO:67985882 ; RVO:68378271 ; RVO:67985556 Keywords : quantum dots * scanning tunneling microscopy * ballistic transport Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.856, year: 2013

  13. Chinese characters reveal impacts of prior experience on very early stages of perception

    Directory of Open Access Journals (Sweden)

    Stollhoff Rainer

    2011-01-01

    Full Text Available Abstract Background Visual perception is strongly determined by accumulated experience with the world, which has been shown for shape, color, and position perception, in the field of visuomotor learning, and in neural computation. In addition, visual perception is tuned to statistics of natural scenes. Such prior experience is modulated by neuronal top-down control the temporal properties of which had been subject to recent studies. Here, we deal with these temporal properties and address the question how early in time accumulated past experience can modulate visual perception. Results We performed stimulus discrimination experiments and compared a group of Chinese participants with a German control group. The perception of our briefly presented visual objects (targets was disturbed by masking stimuli which appeared in close spatiotemporal proximity. These masking stimuli were either intact or scrambled Chinese characters and did not overlap with the targets. In contrast to German controls, Chinese participants show substantial performance differences for real versus scrambled Chinese characters if these masking stimuli were presented as early as less than 100 milliseconds after the onset of the target. For Chinese observers, it even occured that meaningful masking stimuli enhanced target identification if they were shown at least 100 milliseconds after target onset while the same stimuli impaired recognition if presented in close temporal proximity to the target. The latter finding challenges interpretations of our data that solely rely on stimulus contours or geometric properties and emphasizes the impact of prior experience on the very early temporal dynamics of the visual system. Conclusions Our findings demonstrate that prior experience which had been accummulated long before the experiments can modulate the time course of perception intriguingly early, namely already immediately after the perceptual onset of a visual event. This modulation

  14. Preliminary Evidence for the Impact of Combat Experiences on Gray Matter Volume of the Posterior Insula

    Directory of Open Access Journals (Sweden)

    Ashley N. Clausen

    2017-12-01

    Full Text Available Background: Combat-exposed veteran populations are at an increased risk for developing cardiovascular disease. The anterior cingulate cortex (ACC and insula have been implicated in both autonomic arousal to emotional stressors and homeostatic processes, which may contribute to cardiovascular dysfunction in combat veteran populations. The aim of the present study was to explore the intersecting relationships of combat experiences, rostral ACC and posterior insula volume, and cardiovascular health in a sample of combat veterans.Method: Twenty-four male combat veterans completed clinical assessment of combat experiences and posttraumatic stress symptoms. Subjects completed a magnetic resonance imaging scan and autosegmentation using FreeSurfer was used to estimate regional gray matter volume (controlling for total gray matter volume of the rostral ACC and posterior insula. Flow-mediated dilation (FMD was conducted to assess cardiovascular health. Theil-sen robust regressions and Welch's analysis of variance were used to examine relationships of combat experiences and PTSD symptomology with (1 FMD and (2 regional gray matter volume.Results: Increased combat experiences, deployment duration, and multiple deployments were related to smaller posterior insula volume. Combat experiences were marginally associated with poorer cardiovascular health. However, cardiovascular health was not related to rostral ACC or posterior insula volume.Conclusion: The present study provides initial evidence for the relationships of combat experiences, deployment duration, and multiple deployments with smaller posterior insula volume. Results may suggest that veterans with increased combat experiences may exhibit more dysfunction regulating the autonomic nervous system, a key function of the posterior insula. However, the relationship between combat and cardiovascular health was not mediated by regional brain volume. Future research is warranted to further clarify the

  15. Effects of equal channel angular extrusion on microstructure, strength and ballistic performance of AA5754 plates

    DEFF Research Database (Denmark)

    Mishin, Oleg; Hong, Chuanshi; Toftegaard, Helmuth Langmaack

    2014-01-01

    The microstructure, hardness, tensile properties and ballistic performance have been investigated in thick plates of the AA5754 alloy both in a coarse-grained as-received condition and after 4 passes of equal channel angular extrusion (ECAE) conducted at elevated temperatures. It is found that ECAE...... refines the microstructure to an average subgrain size of 0.3 μm, which results in significantly increased hardness and strength. Although ductility decreases due to ECAE, the uniform elongation is still fairly large, ~10%. The ballistic performance of the ECAE-processed material is found...

  16. A Systems Approach to Finding Cost-Effective Alternatives to European Ballistic Missile Defense

    Science.gov (United States)

    2013-09-01

    has holes in its ability to cover the entire region as required. What are the existing approaches to ballistic missile defense in Europe? 4. What Are...however, this report focuses on ballistic missiles which use stellar or inertial guidance systems which are not subject to electromagnetic...location as the Baseline system (35.6° N, 32.5° E) while the other was placed north of Turkey in the Black Sea (41.5° N, 38.1° E). Each Aegis ship was

  17. Models for Ballistic Wind Measurement Error Analysis. Volume II. Users’ Manual.

    Science.gov (United States)

    1983-01-01

    TEST CHART NATIONAL li ’A il (If IANP) ARDl A -CR-83-0008-1 Reports Control Symbol OSO - 1366 MODELS FOR BALLISTIC WIND MEASUREMENTERROR ANALYSIS...AD-A129 360 MODELS FOR BALLSTIC WIND MEASUREMENT ERROR ANALYSIS VO UME 11USERS’ MAN..U) NEW REXICO STATE UNIV LAS U SS CRUCES PHYSICAL SCIENCE LAR...ACCESSION NO. 3. RECIPIENT’S CATALOG NUMBER SASL-CR-83-0008-1 4. TITLE (and Subtitle) 5 TYPE OF REPORT & PERIOD COVERED MODELS FOR BALLISTIC WIND

  18. A ballistics module as a part of the fire control system

    Directory of Open Access Journals (Sweden)

    Branka R. Luković

    2013-10-01

    Full Text Available This article presents a ballistics module as a part of the fire control system of weapons for fire support (mortars, artillery weapons and rocket launchers. The software is "open" with the prominence of autonomy work. It can be modulated and adapted on the user demand. Moreover, it is independent of the hardware base. Introduction: The fire control system is based on a ballistic module (BM which determines the firing data for each weapon tool in the battery. Ballistic calculations, for the given position of the target in relation to the position of tools in the given weather conditions, determine firing data (elevation, direction, timing and locating devices so that the missile seems to cause the desired effect. This paper gives the basic information about the features the BM performs and the manner of their implementation in the fire control system without going into algorithmic solution procedures. Ballistic problem in the fire control system: Ballistic calculation is based on a trajectory calculation of all kinds of projectiles (current, time-fuze, illuminating, smoke, with conventional propulsion, rocket, with built-in gas generator, etc.. Instead of previous solutions, where a trajectory calculation of the fire control system was done by approximate methods, in this BM the trajectory calculation is made by the same model with the same data as for a weapon and ammunition in the process of creating a firing table. The data used in the fire control system are made simultaneously with the preparation of firing tables for a particular tool and associated ammunition,. A modified model of particle, standardized at the NATO level, is also used. Taking into account the meteorological situation, before the trajectory calculation is done, a relative position of the target in relation to the position of the tool should be determined. A selection or loading check is carried out (possibility of reaching a given target as well as the point at which the

  19. Experiments on vibro-impact dynamics of loosely supported tubes under harmonic excitation

    International Nuclear Information System (INIS)

    Axisa, F.; Izquierdo, P.

    1992-01-01

    Computational methods have been recently developed by the authors and others to predict the working life or the acceptable vibration limit of tubular structures experiencing fretting-wear caused by impact-sliding interaction with loose supports or adjacent structures. This problem is of practical interest in various nuclear and other industrial components. This paper reports an experimental work intended to validate the numerical techniques used to compute the tube non-linear vibration in presence of impact-sliding interaction. Attention is especially focused on the local and time averaged dynamical parameters governing the rate of fretting-wear. The experiments were carried out on a straight tube excited harmonically by a pair of electromagnetic shakers. The tube motion was limited by a loose support situated at about midspan. On the other hand, numerical simulations of the tests were also performed. Comparison between test and computational data resulted in rather satisfactory agreement, based on the averaged impact forces and the wear work rate. Results are also discussed in terms of detailed time histories of tube displacement and impact forces

  20. Problem of the reference height of the projectile trajectory as a reduced meteo-ballistic weighting factor

    Directory of Open Access Journals (Sweden)

    Vladimir Cech

    2014-06-01

    Full Text Available This paper deals with the issue of preparation of the aiming angles with the use of tabular firing tables and needed determination of the ballistic elements μB (ballistic wind wB, wxB, wZB, ballistic (virtual temperature τB, ballistic density ρB from the standardized met messages. The weighting factors are used for the calculation of ballistic elements μB that are incorporated into the trajectory calculations characteristics of weapon and ammunition. Two different methodologies practically used in the praxis are analysed and compared. For the comparison of the two methodologies the reference height of trajectory determined from the weighting factor functions is employed. On the basis of the analyses conducted, the potential for further increase in accuracy of these aiming angles preparation methods is pointed out.

  1. Dust generation mechanisms under powerful plasma impacts to the tungsten surfaces in ITER ELM simulation experiments

    International Nuclear Information System (INIS)

    Makhlaj, V.A.; Garkusha, I.E.; Aksenov, N.N.; Chuvilo, A.A.; Chebotarev, V.V.; Landman, I.; Malykhin, S.V.; Pestchanyi, S.; Pugachov, A.T.

    2013-01-01

    In recent tokamak simulation experiments with the QSPA Kh-50 facility several mechanisms of dust generation from tungsten surfaces under ITER ELM-like energy loads have been identified. Here cracking and melting are reported. The brittle destruction dominates after a few transient impacts when a network of major cracks forms on the surface. Bifurcation of major cracks results in ejection of dust particles with sizes up to ∼30 μm. Dust generation occurs also after surface melting and following resolidification when fine crack networks along the grain boundaries develop. In this process the destruction is accompanied by bridge formation due to capillary tension across the fine cracks. Next impacts (even weak melt-free ones) can destroy those bridges, which produces considerable amounts of dust particles of nm-size dust. Surface modification after the repetitive plasma pulses also results in creation of nm-size dust

  2. The Impact of Teen Court on Rural Adolescents: Improved Social Relationships, Psychological Functioning, and School Experiences.

    Science.gov (United States)

    Smokowski, Paul R; Rose, Roderick A; Evans, Caroline B R; Barbee, James; Cotter, Katie L; Bower, Meredith

    2017-08-01

    Teen Court is a prevention program aimed at diverting first time juvenile offenders from the traditional juvenile justice system and reintegrating them into the community. Few studies have examined if Teen Court impacts adolescent functioning. We examined how Teen Court participation impacted psychosocial functioning, social relationships, and school experiences in a sample of 392 rural Teen Court participants relative to two comparison samples, one from the same county as Teen Court (n = 4276) and one from a neighboring county (n = 3584). We found that Teen Court has the potential to decrease internalizing symptoms, externalizing behavior, violent behavior, parent-adolescent conflict, and delinquent friends, and increase self-esteem and school satisfaction.

  3. Laser-driven flier impact experiments at the SG-III prototype laser facility

    International Nuclear Information System (INIS)

    Shui Min; Chu Gen-Bai; Xin Jian-Ting; Wu Yu-Chi; Zhu Bin; He Wei-Hua; Xi Tao; Gu Yu-Qiu

    2015-01-01

    Laser-driven flier impact experiments have been designed and performed at the SG-III prototype laser facility. The continuum phase plate (CPP) technique is used for the 3 ns quadrate laser pulse to produce a relatively uniform irradiated spot of 2 mm. The peak laser intensity is 2.7×10 13  W/cm 2 and it accelerates the aluminum flier with a density gradient configuration to a high average speed of 21.3 km/s, as determined by the flight-of-time method with line VISAR. The flier decelerates on impact with a transparent silica window, providing a measure of the flatness of the flier after one hundred microns of flight. The subsequent shock wave acceleration, pursuing, and decay in the silica window are interpreted by hydrodynamic simulation. This method provides a promising method to create unique conditions for the study of a material’s properties. (paper)

  4. Using Choice Experiments to Assess Environmental Impacts of Dams in Portugal

    Directory of Open Access Journals (Sweden)

    Anabela Botelho

    2015-08-01

    Full Text Available Despite their well-known benefits in electricity production, dams are also responsible for some adverse environmental impacts affecting particularly the wellbeing of residents of the local communities. These environmental damages have not been included in the cost-benefit analysis of hydropower developments mainly because of the difficulty to determine their value. The prime objective of this paper is to measure the economic values of several environmental impacts due to the dams' activity in Portugal, using a discrete choice experiments approach. With the results of this research paper, we expect to contribute to a more efficient and thorough cost-benefit analysis within the complex process of deciding the optimal location of future dams to be built not only in Portugal, but elsewhere. The addition of this stage to the decision-making process allows the integration of economic, social and environmental dimensions, promoting a richer and more informed decision process.

  5. The impact of distraction in natural environments on user experience research

    DEFF Research Database (Denmark)

    Greifeneder, Elke

    2012-01-01

    Laboratories have long been seen as reasonable proxies for user experience research. Yet, this assumption may have become unreliable. The trend toward multiple activities in the users' natural environment, where people simultaneously use a digital library, join a chat or read an incoming Facebook....... The existence and impact of distraction is measured in a standard laboratory setting and in a remote setting that explicitly allows users to work in their own natural environment. The data indicates that there are significant differences between results from the laboratory and natural environment setting...

  6. Boron carbide: hydrocode simulation of plate-impact experiments with an improved failure model

    Science.gov (United States)

    Dyachkov, Sergey; Parshikov, Anatoly; Zhakhovsky, Vasily

    2017-06-01

    Unique strength properties of boron carbide make it useful for numerous applications. However, shock compression accompanied by high strains rates involves material into the process of failure what significantly reduces its strength. In this research we compare simulation results for two sets of plate-impact experiments where samples were manufactured using different technology. Simulations are performed using our 3D SPH hydrocode and the improved Johnson-Holmquist failure model. Complex wave profiles obtained via VISAR are properly reproduced in our modeling. However, it was found that the failed boron carbide strength have a strong effect on the wave profiles and should be different for the each set of experiments. Moreover, heterogeneous distribution of failed boron carbide is shown to affect wave propagation to the rear surface of sample what results in spatial velocity profile variations obtained via line-VISAR system.

  7. Trajectory of Adolescent Obesity: Exploring the Impact of Prenatal to Childhood Experiences

    Science.gov (United States)

    Lanza, H. Isabella; Anglin, M. Douglas

    2013-01-01

    This study examined longitudinal associations of prenatal exposures as well as childhood familial experiences with obesity status from ages 10 to 18. Hierarchical generalized linear modeling (HGLM) was applied to examine 5,156 adolescents from the child sample of the 1979 National Longitudinal Survey of Youth (NLSY79). Higher maternal weight, maternal smoking during pregnancy, lower maternal education, and lack of infant breastfeeding were contributors to elevated adolescent obesity risk in early adolescence. However, maternal age, high birth weight of child, and maternal annual income exhibited long-lasting impact on obesity risk over time throughout adolescence. Additionally, childhood familial experiences were significantly related to risk of adolescent obesity. Appropriate use of family rules in the home and parental engagement in children’s daily activities lowered adolescent obesity risk, but excessive television viewing heightened adolescent obesity risk. Implementation of consistent family rules and parental engagement may benefit adolescents at risk for obesity. PMID:25332643

  8. Impact of legal measures prevent transplant tourism: the interrelated experience of The Philippines and Israel.

    Science.gov (United States)

    Padilla, Benita; Danovitch, Gabriel M; Lavee, Jacob

    2013-11-01

    We describe the parallel changes that have taken place in recent years in two countries, Israel and The Philippines, the former once an "exporter" of transplant tourists and the latter once an "importer" of transplant tourists. These changes were in response to progressive legislation in both countries under the influence of the Declaration of Istanbul. The annual number of Israeli patients who underwent kidney transplantation abroad decreased from a peak of 155 in 2006 to an all-time low of 35 in 2011 while in the Philippines the annual number of foreign transplant recipients fell from 531 in 2007 to two in 2011. The experience of these two countries provides a "natural experiment" on the potential impact of legal measures to prevent transplant tourism.

  9. Impact of the Worst School Experiences in Students: A Retrospective Study on Trauma

    Directory of Open Access Journals (Sweden)

    Paloma Pegolo de Albuquerque

    2015-12-01

    Full Text Available AbstractThe literature indicates damage to students' mental health in cases of school violence. The aim of this retrospective study was to evaluate the psychological impact of school victimization in university students, and to analyze the association between PTSD symptoms and variables related to school victimization. 691 University students responded to the Portuguese version of the Student Alienation and Trauma Survey (SATS. Clinically significant scores in the subscales ranged from 4.7% (somatic symptoms to 20% (hypervigilance, with frequent symptoms described in the literature resulting from school victimization, such as depression, hopelessness, cognitive difficulties, and traumatic event recollection. Additionally, 7.8% of participants presented PTSD symptoms after suffering their "worst school experience". Associations were found between PTSD symptoms and the level of distress after the experience, as well as the perceived benefits after the event, and duration. The results confirm the potential detrimental effects of school victimization, and may be useful to further investigations on this topic.

  10. The impact of presentation format on visual attention and choice in discrete choice experiments

    DEFF Research Database (Denmark)

    Mueller Loose, Simone; Orquin, Jacob Lund

    in the product mock-up presentation required significantly fewer fixations and less decision time, and more within-alternative transitions were observed compared to the verbal and visual presentation formats. Attributes presented visually or at larger size had a higher impact on participants’ choices......Objectives. Discrete choice experiments in which participants choose between alternatives differing on attribute levels are an important research method for preference elicitation. In such experiments choice stimuli is typically presented in tables with verbally described attributes, in tables...... with visual attributes, or as product mock-ups simulating realistic products as close as possible. So far little is known about how presentation formats affect visual attention patterns and choice behavior. This study addresses the question by analysing visual attention and part-worth utilities in choice...

  11. The impact of childhood experience on amygdala response to perceptually familiar black and white faces.

    Science.gov (United States)

    Cloutier, Jasmin; Li, Tianyi; Correll, Joshua

    2014-09-01

    Given the well-documented involvement of the amygdala in race perception, the current study aimed to investigate how interracial contact during childhood shapes amygdala response to racial outgroup members in adulthood. Of particular interest was the impact of childhood experience on amygdala response to familiar, compared with novel, Black faces. Controlling for a number of well-established individual difference measures related to interracial attitudes, the results reveal that perceivers with greater childhood exposure to racial outgroup members display greater relative reduction in amygdala response to familiar Black faces. The implications of such findings are discussed in the context of previous investigations into the neural substrates of race perception and in consideration of potential mechanisms by which childhood experience may shape race perception.

  12. Trajectory of Adolescent Obesity: Exploring the Impact of Prenatal to Childhood Experiences.

    Science.gov (United States)

    Huang, David Y C; Lanza, H Isabella; Anglin, M Douglas

    2014-08-01

    This study examined longitudinal associations of prenatal exposures as well as childhood familial experiences with obesity status from ages 10 to 18. Hierarchical generalized linear modeling (HGLM) was applied to examine 5,156 adolescents from the child sample of the 1979 National Longitudinal Survey of Youth (NLSY79). Higher maternal weight, maternal smoking during pregnancy, lower maternal education, and lack of infant breastfeeding were contributors to elevated adolescent obesity risk in early adolescence. However, maternal age, high birth weight of child, and maternal annual income exhibited long-lasting impact on obesity risk over time throughout adolescence. Additionally, childhood familial experiences were significantly related to risk of adolescent obesity. Appropriate use of family rules in the home and parental engagement in children's daily activities lowered adolescent obesity risk, but excessive television viewing heightened adolescent obesity risk. Implementation of consistent family rules and parental engagement may benefit adolescents at risk for obesity.

  13. A Multiscale Computational Model for Predicting Damage Evolution in Viscoelastic Composites Subjected to Impact Loading

    National Research Council Canada - National Science Library

    Reddy, J. N

    2005-01-01

    ... structures subjected to ballistic impact. The model is three dimensional and computational in nature, utilizing the finite element method, and this model is being implemented to the explicit code DYNA3D...

  14. Impact of operating experience on design of civil structures - An overview

    International Nuclear Information System (INIS)

    Tang, J.H.K.

    1991-01-01

    During the past twenty years, Ontario Hydro has expanded its nuclear power to provide about one third of the electricity used in the province (coal and water powered stations provide the other two thirds). By 1992, the total installed capacity of nuclear generating stations in Ontario will further rise to over 14,000 MW. In common with other power plant design, the layout and structural design of civil facilities for a nuclear generating station are developed from consideration of functional, safety and operational requirements, as well as from past operating experience. Experience on structural performance in the sixteen units of Pickering and Bruce NGS's includes: piping and machinery vibrations, structural fatigue failures, and structural integrity due to extreme loadings not considered in the original design. The operating experience of Ontario Hydro's nuclear stations also indicates that civil structures are subjected to some degree of corrosion or degradation of certain elements similar to other mechanical components in a power station. This category of problems consists of concerns associated with thermal effects on concrete structures due to inoperative cooling system, cracking of concrete, and reliability of elastomeric seal materials at expansion joints of the containment envelop. This paper presents an overview of the operating problems and issues regarding changes in the licensing requirements related to civil structures and supporting systems of major mechanical components. The impact of these generic experience on the design of retrofits and new generating stations is also described in the paper

  15. Sensitivity Experiments on the Impact of Vb-Cyclones to Ocean Temperature and Soil Moisture Changes

    Science.gov (United States)

    Messmer, Martina; José Gómez-Navarro, Juan; Raible, Christoph C.

    2016-04-01

    Cyclones developing over the western Mediterranean and move northeastward are a major source of extreme weather and responsible for heavy precipitation over Central Europe. Gaining insight into these processes is crucial to improve the projection of changes in frequency and severity of these so-called Vb-cyclones under future climate change scenarios. This study explores the impact of climate change on Vb-events through a number of idealized sensitivity experiments that assess the role of the sea surface temperature (SST) and soil moisture and their contribution to the moisture content in the atmosphere in recent Vb-events. To achieve this task, we use the Weather Research and Forecasting model (WRF) to dynamically downscale the ERA Interim reanalysis, simulating five prominent Vb-events that led to extreme precipitation in Central Europe. WRF allows simulating a physical consistent response of Vb-cyclones to different SSTs and soil water volumes. The changes in SSTs are designed to follow the expected temperature changes in a future climate scenario. Additionally the corresponding uncertainty in such projections is considered. Results indicate that although an increase of the Mediterranean SSTs leads to increased precipitation over Central Europe, e.g. 136% greater precipitation in the +5 K experiment compared to the control simulation, a change in the high-impact region of Vb-events at the northern side of the Alps is not found. This counter-intuitive behavior seems to be related to the increase of atmospheric instability over the artificially heated SSTs. Thereby, precipitation notably increases over the east Adriatic coast in response to warmer SSTs, which corresponds to the first location where the air is lifted. However, Vb-events become less destructive in their high-impact region, due to high loss of atmospheric water. Further experiments demonstrate that changing the SSTs of the Atlantic invokes almost no reaction (around 1% change) with respect to

  16. Will woody plant encroachment impact the visitor experience and economy of conservation areas?

    Directory of Open Access Journals (Sweden)

    Emma F. Gray

    2013-02-01

    Full Text Available Woody plant encroachment into savannas is a globally prevalent phenomenon and impacts ecosystem goods and services such as biodiversity, carbon storage, nutrient cycling, grazing and hydrology. The direct ecological and economic consequences for rangelands have been fairly well studied, but, to our knowledge, the economic impact on conservation efforts has not been investigated. African savannas are important as conservation areas because they support large numbers of the world’s remaining megafauna. This study used visitor surveys and long-term mammal distribution data to investigate how an increase in tree density might affect the visibility of animals in a conservation area, which could reduce the satisfaction of visitors to the area. We found that apparent herd sizes and density of animals were much reduced in woody areas, suggesting that visibility is negatively impacted. Visitor surveys determined that a large fraction (almost half of potential future visitors to the park may be lost if animals became more difficult to see and that the majority of these would be the higher-spending visitors. Responses differed depending on the origin of visitors, with international visitors being more interested in seeing animals, whilst local visitors were more content with just being away from the city. The results suggest that woody plant encroachment may have significant impacts on visitor numbers to savanna conservation areas, whilst animal numbers and densities may also be significantly impacted.Conservation implications: The results pointed to potentially significant economic consequences for conservation efforts as visitors become less satisfied with their experience. Perceptions of visitors are important for management decisions as park fees contribute significantly to conservation efforts. This could ultimately result in a reduced capacity for African conservation areas to conserve their biodiversity effectively. The results suggest that

  17. Cerebral activations related to ballistic, stepwise interrupted and gradually modulated movements in Parkinson patients.

    Directory of Open Access Journals (Sweden)

    Carolien M Toxopeus

    Full Text Available Patients with Parkinson's disease (PD experience impaired initiation and inhibition of movements such as difficulty to start/stop walking. At single-joint level this is accompanied by reduced inhibition of antagonist muscle activity. While normal basal ganglia (BG contributions to motor control include selecting appropriate muscles by inhibiting others, it is unclear how PD-related changes in BG function cause impaired movement initiation and inhibition at single-joint level. To further elucidate these changes we studied 4 right-hand movement tasks with fMRI, by dissociating activations related to abrupt movement initiation, inhibition and gradual movement modulation. Initiation and inhibition were inferred from ballistic and stepwise interrupted movement, respectively, while smooth wrist circumduction enabled the assessment of gradually modulated movement. Task-related activations were compared between PD patients (N = 12 and healthy subjects (N = 18. In healthy subjects, movement initiation was characterized by antero-ventral striatum, substantia nigra (SN and premotor activations while inhibition was dominated by subthalamic nucleus (STN and pallidal activations, in line with the known role of these areas in simple movement. Gradual movement mainly involved antero-dorsal putamen and pallidum. Compared to healthy subjects, patients showed reduced striatal/SN and increased pallidal activation for initiation, whereas for inhibition STN activation was reduced and striatal-thalamo-cortical activation increased. For gradual movement patients showed reduced pallidal and increased thalamo-cortical activation. We conclude that PD-related changes during movement initiation fit the (rather static model of alterations in direct and indirect BG pathways. Reduced STN activation and regional cortical increased activation in PD during inhibition and gradual movement modulation are better explained by a dynamic model that also takes into account

  18. Ballistic stretch or aerobic warm-up evoke postexercise hypotension after maximal exercise

    Directory of Open Access Journals (Sweden)

    Raoni Conceição Dos-Santos

    2017-11-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2017v19n4p416   Warm-up is broadly used to increase performance and protect against injury in sports. However, the effects of different models of warm-up on maximal exercise and the subsequent recovery period are undetermined. This study aimed to assess the effects of different warm-ups on performance, blood pressure and autonomic control. Fifity three subjects rested for 5 minutes and then were randomly allocated to one of four experimental groups: Control (CTR, Aerobic Warm-up (AER, Static (SST or Ballistic (BST stretch. Immediately after warm-up, they performed a maximal cycling test and rested for 30 minutes. Heart rate variability (HRV, Systolic (SBP and diastolic (DBP blood pressure were assessed throughout the entire experiment. Statistical analysis was performed by one-way ANOVA with Tukey post-test or two-way ANOVA followed by either Bonferroni or Dunnet post-test, when appropriate. Warm-up did not change test performance or HRV (p>.05, however, when compared between-groups, SBP was higher in BST against all groups (p.05. When compared to baseline values SST showed increased SBP in recovery (p<.05 while only AER and BST showed post-exercise hypotension at 30 minutes (p<.05. In conclusion, despite the lack of effects on performance, AER and BST seem to improve while SST seems to impair the recovery of cardiovascular parameters in an autonomic-independent mechanism.

  19. Impact of Humidity on In Vitro Human Skin Permeation Experiments for Predicting In Vivo Permeability.

    Science.gov (United States)

    Ishida, Masahiro; Takeuchi, Hiroyuki; Endo, Hiromi; Yamaguchi, Jun-Ichi

    2015-12-01

    In vitro skin permeation studies have been commonly conducted to predict in vivo permeability for the development of transdermal therapeutic systems (TTSs). We clarified the impact of humidity on in vitro human skin permeation of two TTSs having different breathability and then elucidated the predictability of in vivo permeability based on in vitro experimental data. Nicotinell(®) TTS(®) 20 and Frandol(®) tape 40mg were used as model TTSs in this study. The in vitro human skin permeation experiments were conducted under humidity levels similar to those used in clinical trials (approximately 50%) as well as under higher humidity levels (approximately 95%). The skin permeability values of drugs at 95% humidity were higher than those at 50% humidity. The time profiles of the human plasma concentrations after TTS application fitted well with the clinical data when predicted based on the in vitro permeation parameters at 50% humidity. On the other hand, those profiles predicted based on the parameters at 95% humidity were overestimated. The impact of humidity was higher for the more breathable TTS; Frandol(®) tape 40mg. These results show that in vitro human skin permeation experiments should be investigated under realistic clinical humidity levels especially for breathable TTSs. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  20. Impact of experience on government policy toward acceptance of hydrogen fuel cell vehicles in Korea

    International Nuclear Information System (INIS)

    Kang, Min Jung; Park, Heejun

    2011-01-01

    As the 'low carbon, green growth' agenda, which emphasized sustainable development through equilibrium between economic growth and environmental preservation, is propagated rapidly in Korea. Despite this progress, it is not uncommon for new products made through advanced technologies, such as hydrogen fuel cell vehicles, to face public skepticism preventing market penetration. Therefore, the factors impacting customer acceptance of hydrogen fuel cell vehicles have to be estimated. Furthermore, it is necessary to examine whether or not the policies related to these products can prevent public skepticism regarding them. This empirical study examining the relationship between personal experiences related to the policy and acceptance of the innovative products of hydrogen fuel cell vehicles shows that government involvement in technology targeting and promotions administered by the 'low carbon, green growth' agenda rarely stimulate potential customers' purchase intentions. Thus, technology targeting administered by the 'low carbon, green growth' agenda needs to be reconciled with customer responses to the future market. - Highlights: → Experience of the 'low carbon, green growth' policy affects perception of it. → Positive perception on the policy seldom arouses positive perception on HFCV performance. → Technology targeting by the policy rarely stimulates purchase intention of HFCV. → Desire to be regarded as a person with environment concern impacts purchase intentions.→ Technology targeting by the policy needs to be reconciled with customer responses to it.

  1. Experiments on the breakup of drop-impact crowns by Marangoni holes

    KAUST Repository

    Aljedaani, Abdulrahman Barakat

    2018-04-04

    We investigate experimentally the breakup of the Edgerton crown due to Marangoni instability when a highly viscous drop impacts on a thin film of lower-viscosity liquid, which also has different surface tension than the drop liquid. The presence of this low-viscosity film modifies the boundary condition, giving effective slip to the drop along the solid substrate. This allows the high-viscosity drop to form a regular bowl-shaped crown, which rises vertically away from the solid and subsequently breaks up through the formation of a multitude of Marangoni holes. Previous experiments have proposed that the breakup of the crown results from a spray of fine droplets ejected from the thin low-viscosity film on the solid, e.g. Thoroddsen et al. (J. Fluid Mech., vol. 557, 2006, pp. 63–72). These droplets can hit the inner side of the crown forming spots with lower surface tension, which drives a thinning patch leading to the hole formation. We test the validity of this assumption with close-up imaging to identify individual spray droplets, to show how they hit the crown and their lower surface tension drive the hole formation. The experiments indicate that every Marangoni-driven patch/hole is promoted by the impact of such a microdroplet. Surprisingly, in experiments with pools of higher surface tension, we also see hole formation. Here the Marangoni stress changes direction and the hole formation looks qualitatively different, with holes and ruptures forming in a repeatable fashion at the centre of each spray droplet impact. Impacts onto films of the same liquid, or onto an immiscible liquid, do not in general form holes. We furthermore characterize the effects of drop viscosity and substrate-film thickness on the overall evolution of the crown. We also measure the three characteristic velocities associated with the hole formation: i.e. the Marangoni-driven growth of the thinning patches, the rupture speed of the resulting thin films inside these patches and finally the

  2. Validation Study of Unnotched Charpy and Taylor-Anvil Impact Experiments using Kayenta

    Energy Technology Data Exchange (ETDEWEB)

    Kamojjala, Krishna [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lacy, Jeffrey [Idaho National Lab. (INL), Idaho Falls, ID (United States); Chu, Henry S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Brannon, Rebecca [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    Validation of a single computational model with multiple available strain-to-failure fracture theories is presented through experimental tests and numerical simulations of the standardized unnotched Charpy and Taylor-anvil impact tests, both run using the same material model (Kayenta). Unnotched Charpy tests are performed on rolled homogeneous armor steel. The fracture patterns using Kayenta’s various failure options that include aleatory uncertainty and scale effects are compared against the experiments. Other quantities of interest include the average value of the absorbed energy and bend angle of the specimen. Taylor-anvil impact tests are performed on Ti6Al4V titanium alloy. The impact speeds of the specimen are 321 m/s and 393 m/s. The goal of the numerical work is to reproduce the damage patterns observed in the laboratory. For the numerical study, the Johnson-Cook failure model is used as the ductile fracture criterion, and aleatory uncertainty is applied to rate-dependence parameters to explore its effect on the fracture patterns.

  3. Exploring students' experience of training for counselling skills and the impact on practice.

    Science.gov (United States)

    Johnston, Bridget; Smith, Val

    2005-08-01

    The aim of this study was to explore participants' experience of an accredited counselling skills course and their perception of its impact on practice. A qualitative design was used utilizing a mixed-method approach. Data were collected using semistructured interviews and the repertory-grid technique. Data were analysed using thematic content analysis (interviews) and the repertory grids were analysed qualitatively using a four-stage procedure. A convenience sample of six healthcare professionals undertaking a counselling skills course completed both interviews. The biggest impact of the course was in the area of self-awareness and skill development. The development of attentive listening, both in terms of objective and subjective findings, was evident. Students perceived that personal qualities, such as warmth and caring, were essential. All participants identified that the group were supportive and that this enhanced learning. The students changed their practice by improving their skills, increasing their awareness and by developing deeper therapeutic relationships with patients and their carers. This research adds to the body of knowledge in palliative care. It identifies key elements in the learning of counselling skills and recognizes the impact of these skills on improving the care of palliative care patients and families.

  4. Impact of audio-visual storytelling in simulation learning experiences of undergraduate nursing students.

    Science.gov (United States)

    Johnston, Sandra; Parker, Christina N; Fox, Amanda

    2017-09-01

    Use of high fidelity simulation has become increasingly popular in nursing education to the extent that it is now an integral component of most nursing programs. Anecdotal evidence suggests that students have difficulty engaging with simulation manikins due to their unrealistic appearance. Introduction of the manikin as a 'real patient' with the use of an audio-visual narrative may engage students in the simulated learning experience and impact on their learning. A paucity of literature currently exists on the use of audio-visual narratives to enhance simulated learning experiences. This study aimed to determine if viewing an audio-visual narrative during a simulation pre-brief altered undergraduate nursing student perceptions of the learning experience. A quasi-experimental post-test design was utilised. A convenience sample of final year baccalaureate nursing students at a large metropolitan university. Participants completed a modified version of the Student Satisfaction with Simulation Experiences survey. This 12-item questionnaire contained questions relating to the ability to transfer skills learned in simulation to the real clinical world, the realism of the simulation and the overall value of the learning experience. Descriptive statistics were used to summarise demographic information. Two tailed, independent group t-tests were used to determine statistical differences within the categories. Findings indicated that students reported high levels of value, realism and transferability in relation to the viewing of an audio-visual narrative. Statistically significant results (t=2.38, psimulation to clinical practice. The subgroups of age and gender although not significant indicated some interesting results. High satisfaction with simulation was indicated by all students in relation to value and realism. There was a significant finding in relation to transferability on knowledge and this is vital to quality educational outcomes. Copyright © 2017. Published by

  5. Exploring painful experiences: impact of emotional narratives on members of a qualitative research team.

    Science.gov (United States)

    Lalor, Joan G; Begley, Cecily M; Devane, Declan

    2006-12-01

    This paper reports a study of the impact of emotional narratives on the well-being of members of a qualitative research team during the conduct of sensitive research. Qualitative data are frequently collected from participants using repeated in-depth interviews when exploring sensitive issues such as loss and grief. The research process can evoke highly emotional responses in the participant and others involved in the study. While consideration has been given to the impact of the research process on participants when a highly affective component is involved, relatively little attention has been given to research team members' experiences. Through analysis of fieldwork records from a grounded theory study of the experiences of women who were carrying a baby with a foetal abnormality, we discuss the affective issues arising in conducting sensitive research. Data sources included two reflexive journals, written comments from two transcribers and the transcript of an interview with the research supervisor. The core category of 'Connecting with the data' emerged, to which each substantive category relates. Three substantive categories -'bearing to watch,''bearing to listen' and 'bearing to support'- emerged as independent but inter-related aspects of the research process as experienced by the researcher, transcribers and supervisor. Methods of protecting the research team and the integrity of the study when the substantive issue is highly emotive are discussed. The emotional impact of research on participants is normally considered prior to the conduct of any sensitive research, and efforts are made to protect them. The potential for researchers, transcribers and supervisors to be harmed should also be carefully considered when planning a project with significant affective elements.

  6. More than a feeling: Emotional cues impact the access and experience of autobiographical memories.

    Science.gov (United States)

    Sheldon, Signy; Donahue, Julia

    2017-07-01

    Remembering is impacted by several factors of retrieval, including the emotional content of a memory cue. Here we tested how musical retrieval cues that differed on two dimensions of emotion-valence (positive and negative) and arousal (high and low)-impacted the following aspects of autobiographical memory recall: the response time to access a past personal event, the experience of remembering (ratings of memory vividness), the emotional content of a cued memory (ratings of event arousal and valence), and the type of event recalled (ratings of event energy, socialness, and uniqueness). We further explored how cue presentation affected autobiographical memory retrieval by administering cues of similar arousal and valence levels in a blocked fashion to one half of the tested participants, and randomly to the other half. We report three main findings. First, memories were accessed most quickly in response to musical cues that were highly arousing and positive in emotion. Second, we observed a relation between a cue and the elicited memory's emotional valence but not arousal; however, both the cue valence and arousal related to the nature of the recalled event. Specifically, high cue arousal led to lower memory vividness and uniqueness ratings, but cues with both high arousal and positive valence were associated with memories rated as more social and energetic. Finally, cue presentation impacted both how quickly and specifically memories were accessed and how cue valence affected the memory vividness ratings. The implications of these findings for views of how emotion directs the access to memories and the experience of remembering are discussed.

  7. Life impact of ankle fractures: Qualitative analysis of patient and clinician experiences

    Directory of Open Access Journals (Sweden)

    McPhail Steven M

    2012-11-01

    Full Text Available Abstract Background Ankle fractures are one of the more commonly occurring forms of trauma managed by orthopaedic teams worldwide. The impacts of these injuries are not restricted to pain and disability caused at the time of the incident, but may also result in long term physical, psychological, and social consequences. There are currently no ankle fracture specific patient-reported outcome measures with a robust content foundation. This investigation aimed to develop a thematic conceptual framework of life impacts following ankle fracture from the experiences of people who have suffered ankle fractures as well as the health professionals who treat them. Methods A qualitative investigation was undertaken using in-depth semi-structured interviews with people (n=12 who had previously sustained an ankle fracture (patients and health professionals (n=6 that treat people with ankle fractures. Interviews were audio-recorded and transcribed. Each phrase was individually coded and grouped in categories and aligned under emerging themes by two independent researchers. Results Saturation occurred after 10 in-depth patient interviews. Time since injury for patients ranged from 6 weeks to more than 2 years. Experience of health professionals ranged from 1 year to 16 years working with people with ankle fractures. Health professionals included an Orthopaedic surgeon (1, physiotherapists (3, a podiatrist (1 and an occupational therapist (1. The emerging framework derived from patient data included eight themes (Physical, Psychological, Daily Living, Social, Occupational and Domestic, Financial, Aesthetic and Medication Taking. Health professional responses did not reveal any additional themes, but tended to focus on physical and occupational themes. Conclusions The nature of life impact following ankle fractures can extend beyond short term pain and discomfort into many areas of life. The findings from this research have provided an empirically derived

  8. The effect of core training on distal limb performance during ballistic strike manoeuvres.

    Science.gov (United States)

    Lee, Benjamin; McGill, Stuart

    2017-09-01

    Ballistic limb motion is enabled by proximal "core" stiffness. However, controversy exists regarding the best method of training this characteristic. This study sought to determine the most effective core training method to enhance distal limb athleticism. A total of 12 participants (24 ± 3 years, 1.8 ± 0.05 m, 76.8 ± 9.7 kg) consisting of Muay Thai athletes performed a core training protocol (Isometric vs. Dynamic, with Control) for 6 weeks, using a repeated measures design to assess performance (peak strike velocity, peak impact force, muscular activation) in various strikes. Isometric training increased impact force in Jab (554.4 ± 70.1 N), Cross (1895.2 ± 203.1 N), Combo (616.8 ± 54.9 N), and Knee (1240.0 ± 89.1 N) trials (P < 0.05). Dynamic training increased strike velocity in Jab (1.3 ± 0.2 m · s -1 ), Cross (5.5 ± 0.9 m · s -1 ), Combo (0.7 ± 0.1, 2.8 ± 0.3 m · s -1 ), and Knee (3.2 ± 0.3 m · s -1 ) trials (P < 0.05). Isometric training increased Combo impact force 935.1 ± 100.3 N greater than Dynamic and 931.6 ± 108.5 N more than Control (P < 0.05). Dynamic training increased Jab strike velocity 1.3 ± 0.1 m · s -1 greater than Isometric and 0.8 ± 0.1 m · s -1 more than Control (P < 0.05). It appears that both static and dynamic approaches to core training are needed to enhance both velocity and force in distal limbs.

  9. Conventional Prompt Global Strike and Long Range Ballistic Missiles: Background and Issues

    Science.gov (United States)

    2017-02-03

    ballistic missiles or caches of weapons of mass destruction (WMD) might allow the United States to destroy these weapons before an adversary could... coherent force structure. Hence, although the Air Force considered the NPR objective of integrating nuclear and conventional strike forces as a

  10. Multiple-Sensor Discrimination of Closely-Spaced Objects on a Ballistic Trajectory

    Science.gov (United States)

    2015-05-18

    26 Table 7. Resulting pignistic probabilities for engagement ........................................................... 26 Table 8. Baseline radar...set of sensors is responsible for observing a complex of objects, selecting a target to engage , and intercepting that target.6 A multiple-sensor...Modeling Two-body orbit dynamics was utilized to generate ballistic trajectories between the desired burnout and reentry points. The dispersion of object

  11. Dynamic material characterization by combining ballistic testing and an engineering model

    NARCIS (Netherlands)

    Carton, E.P.; Roebroeks, G.H.J.J.; Wal, R. van der

    2013-01-01

    At TNO several energy-based engineering models have been created for various failure mechanism occurring in ballistic testing of materials, like ductile hole growth, denting, plugging, etc. Such models are also under development for ceramic and fiberbased materials (fabrics). As the models are

  12. 77 FR 6548 - Notice of Availability of Ballistic Survivability, Lethality and Vulnerability Analyses

    Science.gov (United States)

    2012-02-08

    ... Department of the Army Notice of Availability of Ballistic Survivability, Lethality and Vulnerability... survivability, lethality and vulnerability (SLV) analyses. ARL/SLAD conducts SLV analyses, using the MUVES-S2 vulnerability model, to quantify system, subsystem and/or component level vulnerabilities of ground and air...

  13. Dynamics of ballistically injected latex particles in living human endothelial cells

    NARCIS (Netherlands)

    Li, Y.; Vanapalli Veera, V.S.A.R.; Vanapalli, Srinivas; Duits, Michael H.G.

    2009-01-01

    We studied the dynamics of ballistically injected latex particles (BIP) inside endothelial cells, using video particle tracking to measure the mean squared displacement (MSD) as a function of lag time. The MSD shows a plateau at short times and a linear behavior at longer times, indicating that the

  14. The Advantages of Normalizing Electromyography to Ballistic Rather than Isometric or Isokinetic Tasks.

    Science.gov (United States)

    Suydam, Stephen M; Manal, Kurt; Buchanan, Thomas S

    2017-07-01

    Isometric tasks have been a standard for electromyography (EMG) normalization stemming from anatomic and physiologic stability observed during contraction. Ballistic dynamic tasks have the benefit of eliciting maximum EMG signals for normalization, despite having the potential for greater signal variability. It is the purpose of this study to compare maximum voluntary isometric contraction (MVIC) to nonisometric tasks with increasing degrees of extrinsic variability, ie, joint range of motion, velocity, rate of contraction, etc., to determine if the ballistic tasks, which elicit larger peak EMG signals, are more reliable than the constrained MVIC. Fifteen subjects performed MVIC, isokinetic, maximum countermovement jump, and sprint tasks while EMG was collected from 9 muscles in the quadriceps, hamstrings, and lower leg. The results revealed the unconstrained ballistic tasks were more reliable compared to the constrained MVIC and isokinetic tasks for all triceps surae muscles. The EMG from sprinting was more reliable than the constrained cases for both the hamstrings and vasti. The most reliable EMG signals occurred when the body was permitted its natural, unconstrained motion. These results suggest that EMG is best normalized using ballistic tasks to provide the greatest within-subject reliability, which beneficially yield maximum EMG values.

  15. Hit-to-Kill Guidance Algorithm for the Interception of Ballistic Missiles During the Boost Phase

    Science.gov (United States)

    2006-06-01

    MODELING PROGRAMS...............................................................81 A. 3DOF TARGET...BRFlight3.m .......................................................................................82 B. 3DOF INTERCEPTOR...Degree-of-Freedom ( 3DOF ) model of each. This paper will focus on the Taep’o-dong Two (TD2) ballistic rocket in development by the People’s

  16. Model for ballistic spin-transport in ferromagnet/two-dimensional electron gas/ferromagnet structures

    NARCIS (Netherlands)

    Schapers, T; Nitta, J; Heersche, HB; Takayanagi, H

    The spin dependent conductance of a ferromagnet/two-dimensional electron gas ferromagnet structure is theoretically examined in the ballistic transport regime. It is shown that the spin signal can be improved considerably by making use of the spin filtering effect of a barrier at the ferromagnet

  17. Critical currents in ballistic two-dimensional InAs-based superconducting weak links

    NARCIS (Netherlands)

    Heida, J.P.; Wees, B.J. van; Klapwijk, T.M.; Borghs, G.

    1999-01-01

    The critical supercurrent Ic carried by a short (0.3 to 0.8 µm) ballistic two-dimensional InAs-based electron gas between superconducting niobium electrodes is studied. In relating the maximum value to the resistance of the weak link in the normal state Rn a much lower value is found than

  18. EFFECTS OF STRENGTH VS. BALLISTIC-POWER TRAINING ON THROWING PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Nikolaos Zaras

    2013-03-01

    Full Text Available The purpose of the present study was to investigate the effects of 6 weeks strength vs. ballistic-power (Power training on shot put throwing performance in novice throwers. Seventeen novice male shot-put throwers were divided into Strength (N = 9 and Power (n = 8 groups. The following measurements were performed before and after the training period: shot put throws, jumping performance (CMJ, Wingate anaerobic performance, 1RM strength, ballistic throws and evaluation of architectural and morphological characteristics of vastus lateralis. Throwing performance increased significantly but similarly after Strength and Power training (7.0-13.5% vs. 6.0-11.5%, respectively. Muscular strength in leg press increased more after Strength than after Power training (43% vs. 21%, respectively, while Power training induced an 8.5% increase in CMJ performance and 9.0 - 25.8% in ballistic throws. Peak power during the Wingate test increased similarly after Strength and Power training. Muscle thickness increased only after Strength training (10%, p < 0.05. Muscle fibre Cross Sectional Area (fCSA increased in all fibre types after Strength training by 19-26% (p < 0.05, while only type IIx fibres hypertrophied significantly after Power training. Type IIx fibres (% decreased after Strength but not after Power training. These results suggest that shot put throwing performance can be increased similarly after six weeks of either strength or ballistic power training in novice throwers, but with dissimilar muscular adaptations

  19. Quantum and classical ballistic transport in a chaotic 2D electron channel

    International Nuclear Information System (INIS)

    Luna A, G.A.; Rodriguez, M.A.; Krokhin, A.; Na, K.; Mendez, A.

    1998-01-01

    We review recent results concerning the quantum and classical dynamical properties of ballistic electrons in a ripple channel, their transport properties and its classical-quantum correspondence is analyzed in terms of q uantum Poincare plots , energy level statistics, and certain features of the energy-band spectra. (Author)

  20. Validation of the NATO Armaments Ballistic Kernel for use in small-arms fire control systems

    Directory of Open Access Journals (Sweden)

    D. Corriveau

    2017-06-01

    Full Text Available In support for the development of a new small-arm ballistic computer based on the NATO Armaments Ballistic Kernel (NABK for the Canadian snipers, DRDC Valcartier Research Centre was asked to carry out high-fidelity 6 degree-of-freedom (6-DOF trajectory simulations for a set of relevant vignettes for the snipers, and to compare the direct fire 6-DOF simulation results with those obtained with the 4-DOF NATO Armaments Ballistic Kernel (NABK adapted to simulate small-arm ammunition trajectories. To conduct this study, DRDC Valcartier Research Centre used BALCO v1.0b. This paper presents (1 the process and the methodology employed to carry out the sniper direct fire solution study, (2 the modeling and the simulation of the sniper projectile, the approach used in calculating the firing solutions, and the results of direct fire simulations for the sniper vignettes, and (3 an analysis of firing solutions obtained with the BALCO engine versus those of NABK. The work presented in this paper serves to validate the use of NABK for the new sniper ballistic computer.