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Sample records for charpy v-notch impact

  1. Weld investigations by 3D analyses of Charpy V-notch specimens

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, Allan

    2005-01-01

    The Charpy impact test is a standard procedure for determining the ductile-brittle transition in welds. The predictions of such tests have been investigated by full three dimensional transient analyses of Charpy V-notch specimens. The material response is characterised by an elastic-viscoplastic ......The Charpy impact test is a standard procedure for determining the ductile-brittle transition in welds. The predictions of such tests have been investigated by full three dimensional transient analyses of Charpy V-notch specimens. The material response is characterised by an elastic...... parameters in the weld material differ from those in the base material, and the heat a®ected zone (HAZ) tends to be more brittle than the other material regions. The effect of weld strength undermatch or overmatch is an important issue. Some specimens, for which the notched surface is rotated relative...

  2. Confocal microscopy-fracture reconstruction and finite element modeling characterization of local cleavage toughness in a ferritic/martensitic steel in subsized Charpy V-notch impact tests

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, T. E-mail: yamataku@fusion.imr.tohoku.ac.jp; Odette, G.R.; Lucas, G.E.; Matsui, H

    2000-12-01

    The confocal microscopy (CM)-fracture reconstruction (FR) method, coupled with scanning electron microscopy (SEM) fractography, was used to measure the critical notch deformation conditions at cleavage initiation for two subsized Charpy V-notch (CVN) specimen geometries of Japan ferritic/martensitic steel (JFMS). A new method was developed to permit FR of notched specimens. Three-dimensional finite element analysis (FEA) simulations of the notch and specimen deformation were used to estimate values of critical micro-cleavage fracture stress, {sigma}{sup *}, and critical stressed area, A{sup *}. Since {sigma}{sup *}-A{sup *} is independent of size and geometry, it provides a fundamental local measure of cleavage toughness.

  3. Material inertia and size effects in the Charpy V-notch test

    DEFF Research Database (Denmark)

    Desandre, D. A.; Benzerga, A. A.; Tvergaard, Viggo;

    2004-01-01

    The effect of material inertia on the size dependence of the absorbed energy in the Charpy V-notch test is investigated. The material response is characterized by an elastic-viscoplastic constitutive relation for a porous plastic solid, with adiabatic heating due to plastic dissipation and the re......The effect of material inertia on the size dependence of the absorbed energy in the Charpy V-notch test is investigated. The material response is characterized by an elastic-viscoplastic constitutive relation for a porous plastic solid, with adiabatic heating due to plastic dissipation...

  4. Certification of Charpy V-notch Reference Test Pieces of 80 J Nominal Absorbed Energy (ERM®-FA015x and ERM®-FA015y)

    OpenAIRE

    LAMBERTY MARIE ANDREE; Dean, Alan; Roebben, Gert

    2011-01-01

    This certification report describes the processing and characterisation of ERM®-FA015x and ERM®-FA015y, two batches of Charpy V-notch certified reference test pieces. Sets of five of these test pieces are used for the verification of pendulum impact test machines according to EN 10045-2 (Charpy impact test on metallic materials, Part 2. Method for the verification of impact testing machines) or according to ISO 148-2 (Metallic materials - Charpy pendulum impact test – Part 2: Verification of ...

  5. The evaluation of tempered martensite embrittlement in 4130 steel by instrumented charpy V-notch testing

    Science.gov (United States)

    Zia-Ebrahimi, F.; Krauss, G.

    1983-06-01

    Tempered martensite embrittlement (TME) was studied in vacuum-melted 4130 steel with either 0.002 or 0.02 wt pct P. TME was observed as a severe decrease in Charpy V-notch impact energy, from 46 ft-lb. at 200 °C to 35 ft-lb. at 300 °C in the low P alloy. The impact energy of the high P alloy was consistently lower than that of the low P alloy in all tempered conditions. Fracture was transgranular for all specimens; therefore, segregation of P to the prior austenitic grain boundaries was not a factor in the o°Currence of TME. Analysis of load-time curves obtained by instrumented Charpy testing revealed that the embrittlement is associated with a drop in the pre-maximum-load and post-unstable-fracture energies. In specimens tempered at 400 °C the deleterious effect of phosphorus on impact energy became pronounced, a result more consistent with classical temper embrittlement rather than TME. A constant decrease in pre-maximum-load energy due to phosphorus content was observed. The pre-maximum-load energy decreases with increasing tempering temperature in the range of 200 °C to 400 °C, a result explained by the change in work hardening rate. Carbon extraction replicas of polished and etched as-quenched specimens revealed the presence of Fe2MoC and/or Fe3C carbides retained after austenitizing. Ductile crack extension close to the notch root was related to the formation of fine micro voids at the retained carbides.

  6. Charpy Impact Test on Polymeric Molded Parts

    Directory of Open Access Journals (Sweden)

    Alexandra Raicu

    2012-09-01

    Full Text Available The paper presents the Charpy impact tests on the AcrylonitrileButadiene-Styrene (ABS polymeric material parts. The Charpy impact test, also known as the Charpy V-notch test, is a standardized strain rate test which determines the amount of energy absorbed by a material during fracture. This is a typical method described in ASTM Standard D 6110. We use for testing an Instron - Dynatup equipment which have a fully integrated hardware and software package that let us capture load information at very high speed from the impact tests.

  7. Certification of Charpy V-Notch Reference Test Pieces of 30 J Nominal Absorbed Energy - Certified Reference Materials ERM®-FA013bg and ERM®-FA013bh

    OpenAIRE

    LAMBERTY MARIE ANDREE; Dean, Alan; Roebben, Gert

    2011-01-01

    This certification report describes the processing and characterisation of ERM®-FA013bg and ERM®-FA013bh, two batches of Charpy V-notch certified reference test pieces. Sets of five of these test pieces are used for the verification of pendulum impact test machines according to EN 10045-2 (Charpy impact test on metallic materials, Part 2. Method for the verification of impact testing machines [1]) or according to ISO 148-2 (Metallic materials - Charpy pendulum impact test - Part 2: Verificati...

  8. A study of the fracture process and factors that control toughness variability in Charpy V-notch specimens

    Science.gov (United States)

    Bouchard, Real

    La presente etude a ete initiee pour developper une comprehension quantitative du processus de rupture avec les facteurs qui controlent la dispersion des mesures de tenacite lorsque des eprouvettes Charpy entaillees en V sont utilisees. Un grand nombre d'essais ont ete realises pour un acier C-Mn: eprouvettes Charpy testees sous impact, eprouvettes Charpy testees en flexion lente, eprouvettes axisymetriques entaillees et sollicitees en traction et essais de tenacite sur eprouvettes prefissurees. Base sur le concept de la statistique de Weibull, l'approche locale developpee par le groupe Beremin a ete utilisee pour decrire la probabilite de rupture par clivage en fonction de la contrainte appliquee aussi bien qu'en fonction de l'energie Charpy obtenue. Le calcul par elements finis a ete realise pour determiner la distribution de la deformation et des contraintes en pointe d'entaille et de fissure. La nouvelle approche introduite decrit bien les resultats experimentaux. Les points d'initiation du clivage ont ete identifies au MEB et par la suite, avec la technique de faisceau d'ions focalise, sectionnes, polis et examines. L'examen de la microstructure sous le point d'initiation revele clairement que le clivage s'initie par un mecanisme d'empilement de dislocations ou les dislocations sont arretees aux joints de grain, aux interfaces de perlite/ferrite ou de perlite qui agissent comme barrieres physiques.

  9. Reconstituted Charpy impact specimens. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Perrin, J.S.; Wullaert, R.A.; McConnell, P.; Server, W.L.; Fromm, E.O.

    1982-12-01

    The arc stud welding process was used to produce new, full size Charpy V-notch impact specimens from halves of Charpy specimens which had been previously tested. The apparatus was developed such that it could be used not only for unirradiated specimens, but also so that it could be adapted for in-cell use to produce new reconstituted specimens of irradiated material. The materials studied are of interest in nuclear applications. They include A533B, A36, A516-80, submerged arc weld metal (A508 base metal), HY80, cast duplex stainless steel, irradiated A533B, and irradiated submerged arc weld metal (A508 base metal). Both unirradiated and irradiated specimens were successfully produced and subsequently impact tested. In general, there was excellent agreement when comparing the original curves to the subsequent curves generated with reconstituted specimens. This program has shown that the arc stud welding process is well suited for producing reconstituted specimens at a reasonable cost using either unirradiated or irradiated material.

  10. Dynamic Toughness Testing of Pre-Cracked Charpy V-Notch Specimens. Convention ELECTRABEL - SCK-CEN

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E

    1999-04-01

    This document describes the experimental and analytical procedures which have been adopted at the laboratories of the Belgian Nuclear Research Centre SCK-CEN for performing dynamic toughness tests on pre-cracked Charpy-V specimens. Such procedures were chosen on the basis of the existing literature on the subject, with several updates in the data analysis stages which reflect more recent developments in fracture toughness testing. Qualification tests have been carried out on PCCv specimens of JRQ steel, in order to assess the reliability of the results obtained; straightforward comparisons with reference data have been performed, as well as more advanced analyses using the Master Curve approach. Aspects related to machine compliance and dynamic tup calibration have also been addressed.

  11. Assessment of Ductile-to-Brittle Transition Behavior of Localized Microstructural Regions in a Friction-Stir Welded X80 Pipeline Steel with Miniaturized Charpy V-Notch Testing

    Science.gov (United States)

    Avila, Julian A.; Lucon, Enrico; Sowards, Jeffrey; Mei, Paulo Roberto; Ramirez, Antonio J.

    2016-06-01

    Friction-stir welding (FSW) is an alternative welding process for pipelines. This technology offers sound welds, good repeatability, and excellent mechanical properties. However, it is of paramount importance to determine the toughness of the welds at low temperatures in order to establish the limits of this technology. Ductile-to-brittle transition curves were generated in the present study by using a small-scale instrumented Charpy machine and miniaturized V-notch specimens (Kleinstprobe, KLST); notches were located in base metal, heat-affected, stirred, and hard zones within a FSW joint of API-5L X80 Pipeline Steel. Specimens were tested at temperatures between 77 K (-196 °C) and 298 K (25 °C). Based on the results obtained, the transition temperatures for the base material and heat-affected zone were below 173 K (-100 °C); conversely, for the stirred and hard zones, it was located around 213 K (-60 °C). Fracture surfaces were characterized and showed a ductile fracture mechanism at high impact energies and a mixture of ductile and brittle mechanisms at low impact energies.

  12. Dynamic fracture toughness and Charpy impact properties of an AISI 403 martensitic stainless steel

    Science.gov (United States)

    Sreenivasan, P. R.; Ray, S. K.; Mannan, S. L.; Rodriguez, P.

    1996-04-01

    Dynamic fracture toughness and Charpy impact properties of a normalised and tempered AISI 403 martensitic stainless steel obtained from instrumented impact tests are presented. Procedures for estimating dynamic fracture toughness ( KId) from the load-time traces obtained in instrumented tests of unprecracked Charpy V-notch (CVN) specimens are considered. The estimated KId values show reasonable agreement with those obtained from instrumented drop-weight and precracked Charpy tests. Also, except in the upper transition and uppershelf regions, the ASME KIR curve is generally conservative (i.e. gives lower KId values) when compared to the above KId estimates. The conservatism of the ASME KIR at the upper transition and uppershelf temperatures needs verification/validation. The lowest KId values estimated at the lower shelf temperatures for the above steel, namely, 33-42 MPa√m are in good agreement with the reported values of 35-50 MPa√m for the same steel in the literature.

  13. Fracture toughness and Charpy impact properties of several RAFMS before and after irradiation in HFIR

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, M.A. [Oak Ridge National Laboratory, Oak Ridge, TN 37831-6151 (United States)]. E-mail: sokolovm@ornl.gov; Tanigawa, H. [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Odette, G.R. [University of California-Santa Barbara, Santa Barbara, CA 93106-5080 (United States); Shiba, K. [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Klueh, R.L. [Oak Ridge National Laboratory, Oak Ridge, TN 37831-6151 (United States)

    2007-08-01

    As part of the development of candidate reduced-activation ferritic steels for fusion applications, several steels, namely F82H, 9Cr-2WVTa steels and F82H weld metal, are being investigated in the joint DOE-JAEA collaboration program. Within this program, three capsules containing a variety of specimen designs were irradiated at two design temperatures in the ORNL High Flux Isotope Reactor (HFIR). Two capsules, RB-11J and RB-12J, were irradiated in the HFIR removable beryllium positions with europium oxide (Eu{sub 2}O{sub 3}) thermal neutron shields in place. Specimens were irradiated up to 5 dpa. Capsule JP25 was irradiated in the HFIR target position to 20 dpa. The design temperatures were 300 {sup o}C and 500 {sup o}C. Precracked third-sized V-notch Charpy (3.3 x 3.3 x 25.4 mm) and 0.18 T DC(T) specimens were tested to determine transition and ductile shelf fracture toughness before and after irradiation. The master curve methodology was applied to evaluate the fracture toughness transition temperature, T {sub 0}. Irradiation induced shifts of T {sub 0} and reductions of J {sub Q} were compared with Charpy V-notch impact properties. Fracture toughness and Charpy shifts were also compared to hardening results.

  14. Superior Charpy impact properties of ODS ferritic steel irradiated in JOYO

    Science.gov (United States)

    Kuwabara, T.; Kurishita, H.; Ukai, S.; Narui, M.; Mizuta, S.; Yamazaki, M.; Kayano, H.

    1998-10-01

    The effect of neutron irradiation on Charpy impact properties of an ODS ferritic steel developed by PNC was studied. The miniaturized Charpy V-notch (MCVN) specimens (1.5 × 1.5 × 20 mm) of two orientations (longitudinal, called 1DS-L, and transverse, 1DS-T) were irradiated to fluence levels of (0.3-3.8) × 10 26 n/m 2 ( E n > 0.1 MeV) between 646 and 845 K in JOYO. MCVN specimens before and after the irradiation were subjected to instrumented Charpy impact tests. The test results and fracture surface observations showed that in the unirradiated state the steel showed no ductile-to-brittle transition behavior until 153 K regardless of orientation and the upper shelf energy of the steel was as high as that of a high-strength ferritic steel without dispersed oxide. Such excellent impact properties were essentially maintained after the irradiation although an appreciable decrease in absorbed energy occurred by higher temperature irradiations at and above 793 K.

  15. Fracture behaviors of neutron-irradiated ferritic steels studied by the instrumented charpy impact test

    Science.gov (United States)

    Yoshida, H.; Miyata, K.; Narui, M.; Kayano, H.

    1989-12-01

    The instrumented Charpy impact test for quarter-size specimens was developed and applied to study fracture behavior of ferritic steels and a ferritic-martensitic steel (JFMS) before and after neutron irradiation. The load-deflection curves obtained for U- and V-notched specimens showed typical characteristics of fracture properties of these steels. The temperature dependence of the fracture energy ( Ef) and the failure deflection ( Df) clearly indicates ductile-brittle transition and the DBTT can be determined from the Ef and Df versus temperature curves. The V-notched specimens showed sharper transition at higher temperatures for the JFMS than the U-notched ones, where the former were sensitive to brittle fracture and the latter well demonstrated the behavior of crack propagation. For the ferritic steels the DBTTs showed low values at compositions containing approximate 8-10% Cr and the increase of the DBTT (Δ DBTT) due to irradiation also showed a similar tendency. The Δ DBTT appeared to be relatively larger for the JFMS than the ferritic steels.

  16. Quality assurance of absorbed energy in Charpy impact test

    Science.gov (United States)

    Rocha, C. L. F.; Fabricio, D. A. K.; Costa, V. M.; Reguly, A.

    2016-07-01

    In order to ensure the quality assurance and comply with standard requirements, an intralaboratory study has been performed for impact Charpy tests, involving two operators. The results based on ANOVA (Analysis of Variance) and Normalized Error statistical techniques pointed out that the execution of the tests is appropriate, because the implementation of quality assurance methods showed acceptable results.

  17. Ultrahigh Charpy impact toughness (~450J) achieved in high strength ferrite/martensite laminated steels

    Science.gov (United States)

    Cao, Wenquan; Zhang, Mingda; Huang, Chongxiang; Xiao, Shuyang; Dong, Han; Weng, Yuqing

    2017-01-01

    Strength and toughness are a couple of paradox as similar as strength-ductility trade-off in homogenous materials, body-centered-cubic steels in particular. Here we report a simple way to get ultrahigh toughness without sacrificing strength. By simple alloying design and hot rolling the 5Mn3Al steels in ferrite/austenite dual phase temperature region, we obtain a series of ferrite/martensite laminated steels that show up-to 400–450J Charpy V-notch impact energy combined with a tensile strength as high as 1.0–1.2 GPa at room temperature, which is nearly 3–5 times higher than that of conventional low alloy steels at similar strength level. This remarkably enhanced toughness is mainly attributed to the delamination between ferrite and martensite lamellae. The current finding gives us a promising way to produce high strength steel with ultrahigh impact toughness by simple alloying design and hot rolling in industry. PMID:28150692

  18. Ultrahigh Charpy impact toughness (~450J) achieved in high strength ferrite/martensite laminated steels.

    Science.gov (United States)

    Cao, Wenquan; Zhang, Mingda; Huang, Chongxiang; Xiao, Shuyang; Dong, Han; Weng, Yuqing

    2017-02-02

    Strength and toughness are a couple of paradox as similar as strength-ductility trade-off in homogenous materials, body-centered-cubic steels in particular. Here we report a simple way to get ultrahigh toughness without sacrificing strength. By simple alloying design and hot rolling the 5Mn3Al steels in ferrite/austenite dual phase temperature region, we obtain a series of ferrite/martensite laminated steels that show up-to 400-450J Charpy V-notch impact energy combined with a tensile strength as high as 1.0-1.2 GPa at room temperature, which is nearly 3-5 times higher than that of conventional low alloy steels at similar strength level. This remarkably enhanced toughness is mainly attributed to the delamination between ferrite and martensite lamellae. The current finding gives us a promising way to produce high strength steel with ultrahigh impact toughness by simple alloying design and hot rolling in industry.

  19. Microstructural characterization of Charpy-impact-tested nanostructured bainite

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Y.T.; Chang, H.T.; Huang, B.M. [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan, ROC (China); Huang, C.Y. [Iron and Steel R& D Department, China Steel Corporation, Kaohsiung, Taiwan, ROC (China); Yang, J.R., E-mail: jryang@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan, ROC (China)

    2015-09-15

    In this work, a possible cause of the extraordinary low impact toughness of nanostructured bainite has been investigated. The microstructure of nanostructured bainite consisted chiefly of carbide-free bainitic ferrite with retained austenite films. X-ray diffractometry (XRD) measurement indicated that no retained austenite existed in the fractured surface of the Charpy-impact-tested specimens. Fractographs showed that cracks propagated mainly along bainitic ferrite platelet boundaries. The change in microstructure after impact loading was verified by transmission electron microscopy (TEM) observations, confirming that retained austenite was completely transformed to strain-induced martensite during the Charpy impact test. However, the zone affected by strained-induced martensite was found to be extremely shallow, only to a depth of several micrometers from the fracture surface. It is appropriately concluded that upon impact, as the crack forms and propagates, strain-induced martensitic transformation immediately occurs ahead of the advancing crack tip. The successive martensitic transformation profoundly facilitates the crack propagation, resulting in the extremely low impact toughness of nanostructured bainite. Retained austenite, in contrast to its well-known beneficial role, has a deteriorating effect on toughness during the course of Charpy impact. - Highlights: • The microstructure of nanostructured bainite consisted of nano-sized bainitic ferrite subunits with retained austenite films. • Special sample preparations for SEM, XRD and TEM were made, and the strain-affected structures have been explored. • Retained austenite films were found to transform into martensite after impact loading, as evidenced by XRD and TEM results. • The zone of strain-induced martensite was found to extend to only several micrometers from the fracture surface. • The poor Charpy impact toughness is associated with the fracture of martensite at a high strain rate during

  20. Effect of grain structure on Charpy impact behavior of copper

    Science.gov (United States)

    Liang, Ningning; Zhao, Yonghao; Wang, Jingtao; Zhu, Yuntian

    2017-01-01

    Nanostructured (NS) and ultrafine-grained (UFG) materials have high strength and relatively low ductility. Their toughness has not been comprehensively investigated. Here we report the Charpy impact behavior and the corresponding microstructural evolutions in UFG Cu with equi-axed and elongated grains which were prepared by equal channel angular pressing (ECAP) for 2 and 16 passes at room temperature. It is found that their impact toughness (48 J/cm2) is almost comparable to that of coarse grained (CG) Cu: 55 J/cm2. The high strain rate during the Charpy impact was found to enhance the strain hardening capability of the UFG Cu due to the suppression of dynamic dislocation recovery. The crack in the CG Cu was blunted by dislocation-slip mediated plastic deformation, while the cracks in the UFG Cu were formed at grain boundaries and triple junctions due to their limited plasticity. Near the crack surfaces the elongated grains in ECAP-2 sample were refined by recrystallization, while equi-axed grains in the ECAP-16 sample grew larger. PMID:28303950

  1. Charpy Impact Energy and Microindentation Hardness of 60-NITINOL

    Science.gov (United States)

    Stanford, Malcolm K.

    2012-01-01

    60-NITINOL (60 wt.% Ni 40 wt.% Ti) is being studied as a material for advanced aerospace components. The Charpy impact energy and microindentation hardness has been studied for this material, fabricated by vacuum induction skull melting (casting) and by hot isostatic pressing. Test specimens were prepared in various hardened and annealed heat treatment conditions. The average impact energy ranged from 0.33 to 0.49J for the hardened specimens while the annealed specimens had impact energies ranging from 0.89 to 1.18J. The average hardness values of the hardened specimens ranged from 590 to 676 HV while that of the annealed specimens ranged from 298 to 366 HV, suggesting an inverse relationship between impact energy and hardness. These results are expected to provide guidance in the selection of heat treatment processes for the design of mechanical components.

  2. Experimental study on the material dynamic fracture properties by Instrumented Charpy Impact test with single specimen method

    Science.gov (United States)

    Jian, F.; Fulian, D.; Chengzhong, W.

    2003-09-01

    With the determination of load-time curve recorded by Amsler/Roell RKP 450 Instrumented Charpy Impact test and based on the Newton's Second Law, Impact character of a single standard V-notch specimen of X70 pipeline steel under the low temperature -70 ^{circ}C was investigated by studying the impact energy distribution. It was revealed that maximum load point (Fm point) was not exact the dynamic crack initiation, which was detected somewhere prior and very close to Fm point by using Compliance Changing Rate method. This fact was also confirmed by Dynamic CTOD method. That is to say, Impact energy related to the Fm point (i.e. Em) consists not only the crack initiation energy Ei, but a small part of crack extension energy as well. Ratio of Ei/Em was found to be 0.90 just applicable to the material used here. Dynamic fracture toughness JJd was then estimated by modified Rice equation. Crack extension behavior and dynamic crack growth resistance curve (J-Δa) during stable crack propagation period was carefully analyzed by Key Curve method. Finally, methods for evaluating tearing module Tmat, and CTOD curve under the impact test were also briefly introduced in the paper.

  3. 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.

  4. Instrumented charpy impact tests of austenitic and ferritic steels

    Science.gov (United States)

    Yoshida, H.; Miyata, K.; Hayashi, Y.; Narui, M.; Kayano, H.

    1985-08-01

    The instrumented Charpy impact test was applied to commercial Mn-steel and ferritic steels before and after JMTR irradiation ( 6.5 × 10 22 n/m 2). The load-deflection curves show typical characteristics of the fracture properties of the specimens; i.e. linear elastic behaviour for the brittle fracture and elastic-plastic behaviour for the ductile fracture. The fracture deflection and the absorption energy (fracture energy) dropped rapidly at the temperature of ductile to brittle transition. The ductile-brittle transition temperatures (DBTTs) showed shifts of about 30 and 40 K due to the irradiation for 9Cr-1Mo and 9Cr-2Mo steels, respectively. In Mn-steel the transition from ductile to brittle did not appear at temperatures higher than 77 K. The lateral expansions measured from the scanning electron micrographs show good correspondence to the above results.

  5. Numerical modelling of Charpy-V notch test by local approach to fracture. Application to an A508 steel in the ductile-brittle transition range; Modelisation de l'essai Charpy par l'approche locale de la rupture. Application au cas de l'acier 16MND5 dans le domaine de transition

    Energy Technology Data Exchange (ETDEWEB)

    Tanguy, B

    2001-07-15

    Ferritic steels present a transition of the rupture mode which goes progressively of a brittle rupture (cleavage) to a ductile rupture when the temperature increases. The following of the difference of the transition temperature of the PWR vessel steel by the establishment of toughness curves makes of the Charpy test an integrating part of the monitoring of the French PWR reactors. In spite of the advantages which are adapted to it in particular its cost, the Charpy test does not allow to obtain directly a variable which characterizes a crack propagation resistance as for instance the toughness used for qualifying the mechanical integrity of a structure. This work deals with the establishment of the through impact strength-toughness in the transition range of the vessel steel: 16MND5 from a non-empirical approach based on the local approach of the rupture. The brittle rupture is described by the Beremin model (1983), which allows to describe the dispersion inherent in this rupture mode. The description of the brittle fissure is carried out by the GTN model (1984) and by the Rousselier model (1986). This last model has been modified in order to obtain a realistic description of the brittle damage in the case of fast solicitations and of local heating. The method proposed to determine the parameters of the damage models depends only of tests on notched specimens and of the inclusion data of the material. The behaviour is described by an original formulation parametrized in temperature which allows to describe all the tests carried out in this study. Before using this methodology, an experimental study of the behaviour and of the rupture modes of the steel 16MND5 has been carried out. From the toughness tests carried out in quasi-static and dynamical conditions, it has been revealed that this steel does not present important unwedging of its toughness curve due to the velocity effect. In the transition range, local heating of about 150 C have been measured in the root

  6. An improved correlation procedure for subsize and full-size Charpy impact specimen data

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, M.A.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)

    1997-03-01

    The possibility of using subsize specimens to monitor the properties of reactor pressure vessel steels is receiving increasing attention for light-water reactor plant life extension. This potential results from the possibility of cutting samples of small volume form the internal surface of the pressure vessel for determination of the actual properties of the operating pressure vessel. In addition, plant life extension will require supplemental data that cannot be provided by existing surveillance programs. Testing of subsize specimens manufactured from broken halves of previously tested surveillance Charpy specimens offers an attractive means of extending existing surveillance programs. Using subsize Charpy V-notch-type specimens requires the establishment of a specimen geometry that is adequate to obtain a ductile-to-brittle transition curve similar to that obtained from full-size specimens, and the development of correlations for transition temperature and upper-shelf energy (USE) level between subsize and full-size specimens. Five different geometries of subsize specimens were selected for testing and evaluation. The specimens were made from several types of pressure vessel steels with a wide range of yield strengths, transition temperatures, and USEs. The effects of specimen dimensions, including notch depth, angle, and radius, have been studied. The correlations of transition temperatures determined from different types of subsize specimens and the full-size specimens are presented. A new procedure for transforming data from subsize specimens is developed. The transformed data are in good agreement with data from full-size specimens for materials that have USE levels less than 200 J.

  7. Analysis of the Charpy V-notch test for welds

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, A.

    2000-01-01

    strength variations in a weldment in a HY100 steel. The predicted work to fracture shows a strong sensitivity to the location of the notch relative to the weld, with the most brittle behavior for a notch close to the narrow heat affected zone. The analyses illustrate the strong dependence of the transition...

  8. Tensile and charpy impact properties of irradiated reduced-activation ferritic steels

    Energy Technology Data Exchange (ETDEWEB)

    Klueh, R.L.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    Tensile tests were conducted on eight reduced-activation Cr-W steels after irradiation to 15-17 and 26-29 dpa, and Charpy impact tests were conducted on the steels irradiated to 26-29 dpa. Irradiation was in the Fast Flux Test Facility at 365{degrees}C on steels containing 2.25-12% Cr, varying amounts of W, V, and Ta, and 0.1%C. Previously, tensile specimens were irradiated to 6-8 dpa and Charpy specimens to 6-8, 15-17, and 20-24 dpa. Tensile and Charpy specimens were also thermally aged to 20000 h at 365{degrees}C. Thermal aging had little effect on the tensile behavior or the ductile-brittle transition temperature (DBTT), but several steels showed a slight increase in the upper-shelf energy (USE). After {approx}7 dpa, the strength of the steels increased and then remained relatively unchanged through 26-29 dpa (i.e., the strength saturated with fluence). Post-irradiation Charpy impact tests after 26-29 dpa showed that the loss of impact toughness, as measured by an increase in DBTT and a decrease in the USE, remained relatively unchanged from the values after 20-24 dpa, which had been relatively unchanged from the earlier irradiations. As before, the two 9Cr steels were the most irradiation resistant.

  9. Effect of low temperatures on charpy impact toughness of austempered ductile irons

    Science.gov (United States)

    Riabov, Mikhail V.; Lerner, Yury S.; Fahmy, Mohammed F.

    2002-10-01

    Impact properties of standard American Society for Testing Materials (ASTM) grades of austempered ductile iron (ADI) were evaluated at subzero temperatures in unnotched and V-notched conditions and compared with ferritic and pearlitic grades of ductile irons (DIs). It was determined that there is a decrease in impact toughness for all ADI grades when there is a decrease in content of retained austenite and a decrease in test temperature, from room temperature (RT) to -60 °C. However, the difference in impact toughness values was not so noticeable for low retained austenite containing grade 5 ADI at both room and subzero temperatures as it was for ADI grade 1. Furthermore, the difference in impact toughness values of V-notched specimens of ADI grades 1 and 5 tested at -40 °C was minimal. The impact behaviors of ADI grade 5 and ferritic DI were found to be more stable than those of ADI grades 1, 2, 3, and 4 and pearlitic DI when the testing temperature was decreased. The impact toughness of ferritic DI was higher than that of ADI grades 1 and 2 at both -40 °C and -60 °C. The impact properties of ADI grades 4 and 5 were found to be higher than that of pearlitic DI at both -40 °C and -60 °C. The scanning electron microscopy (SEM) study of fracture surfaces revealed mixed ductile and quasicleavage rupture morphology types in all ADI samples tested at both -40 °C and -60 °C. With decreasing content of retained austenite and ductility, the number of quasicleavage facets increased from ADI grade 1-5. It was also found that fracture morphology of ADI did not experience significant changes when the testing temperature decreased. Evaluation of the bending angle was used to support impact-testing data. Designers and users of ADI castings may use the data developed in this research as a reference.

  10. Influence of Stacking Sequence and Notch Angle on the Charpy Impact Behavior of Hybrid Composites

    Science.gov (United States)

    Behnia, S.; Daghigh, V.; Nikbin, K.; Fereidoon, A.; Ghorbani, J.

    2016-09-01

    The low-velocity impact behavior of hybrid composite laminates was investigated. The epoxy matrix was reinforced with aramid, glass, basalt, and carbon fabrics using the hand lay-up technique. Different stacking sequences and notch angles were and notch angles considered and tested using a Charpy impact testing machine to study the hybridization and notch angle effects on the impact response of the hybrid composites. The energy absorption capability of specimens with different stacking sequences and notch angles is compared and discussed. It is shown that the hybridization can enhance the mechanical performance of composite materials.

  11. Behavior of Aramid Fiber/Ultrahigh Molecular Weight Polyethylene Fiber Hybrid Composites under Charpy Impact and Ballistic Impact

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The aramid fiber/UHMWPE (ultrahigh molecular weight polyethylene) fiber hybrid composites (AF/DF) were manufactured. By Charpy impact, the low velocity impact behavior of AF/DF composite was studied. And the high velocity impact behavior under ballistic impact was also investigated. The influence of hybrid ratio on the performances of low and high velocity impact was analyzed, and hybrid structures with good impact properties under low velocity impact and high velocity were optimized. For Charpy impact, the maximal impact load increased with the accretion of the AF layers for AF/DF hybrid composites. The total impact power was reduced with the decrease of DF layers and the delamination can result in the increase of total impact power. For ballistic impact, the DF ballistic performance was better than that of the AF and the hybrid ratio had a crucial influence. The failure morphology of AF/DF hybrid composite under Charpy impact and ballistic impact was analyzed. The AF/DF hybrid composites in suitable hybrid ratio could attain better performance than AF or DF composites.

  12. A New Analytical Expression for the Relationship Between the Charpy Impact Energy and Notch Tip Position for Functionally Graded Steels

    Institute of Scientific and Technical Information of China (English)

    H.Samareh Salavati Pour; F.Berto; Y.Alizadeh

    2013-01-01

    The effect of the distance between the notch tip and the position of the middle phase in the FGSs on the Charpy impact energy is investigated in the present paper.The results show that when the notch apex is close to the middle layer,the Charpy impact energy reaches its maximum value.This is due to the increment of the absorbed energy by plastic deformation ahead of the notch tip.On the other hand,when the notch tip is far from the middle layer,the Charpy impact energy strongly decreases.Another fundamental motivation of the present work is that for crack arrester configuration,no accurate mathematical or analytical modelling is available up to now.By considering the relationship between the Charpy impact energy and the plastic volume size,a new theoretical model has been developed to link the Charpy impact energy with the distance from the notch apex to the middle phase.This model is a simplified one and the effect of different shapes of the layers and the effect of microstructure on the mechanical properties and plastic region size will be considered in further investigation.The results of the new developed closed form expression show a sound agreement with some recent experimental results taken from the literature.

  13. Experimental study on variations in Charpy impact energies of low carbon steel, depending on welding and specimen cutting method

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhaorui; Kang, Hansaem; Lee, Young Seog [Chung-Ang University, Seoul (Korea, Republic of)

    2016-05-15

    This paper presents an experimental study that examines variations of Charpy impact energy of a welded steel plate, depending upon the welding method and the method for obtaining the Charpy specimens. Flux cored arc welding (FCAW) and Gas tungsten arc welding (GTAW) were employed to weld an SA516 Gr. 70 steel plate. The methods of wire cutting and water-jet cutting were adopted to take samples from the welded plate. The samples were machined according to the recommendations of ASTM SEC. II SA370, in order to fit the specimen dimension that the Charpy impact test requires. An X-ray diffraction (XRD) method was used to measure the as-weld residual stress and its redistribution after the samples were cut. The Charpy impact energy of specimens was considerably dependent on the cutting methods and locations in the welded plate where the specimens were taken. The specimens that were cut by water jet followed by FCAW have the greatest resistance-to-fracture (Charpy impact energy). Regardless of which welding method was used, redistributed transverse residual stress becomes compressive when the specimens are prepared using water-jet cutting. Meanwhile, redistributed transverse residual stress becomes tensile when the specimens are prepared using wire cutting.

  14. 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.

  15. Unnotched Charpy Impact Energy Transition Behavior of Austempered Engineering Grade Ductile Iron Castings

    Science.gov (United States)

    Kisakurek, Sukru Ergin; Ozel, Ahmet

    2014-04-01

    Unnotched Charpy impact energy transition behavior of five different engineering grade ductile iron castings, as specified by EN 1563 Standards, were examined in as-cast, as well as in austempered states. ADIs were produced with the maximum impact energy values permissible for the grades. Austempering treatment detrimented the sub-zero impact properties of the ferritic castings, but considerably enhanced those of the pearlitic-ferritic irons. The impact energy transition behavior of the austempered states of all the grades examined were noted to be determined by the progressive transformation of the unavoidable carbon-unsaturated and untransformed regions of the austenite remaining in the matrix of the austempered ductile iron to martensite with decreasing temperature.

  16. Effect of Cadmium Plating Thickness on the Charpy Impact Energy of Hydrogen-Charged 4340 Steel

    Science.gov (United States)

    Es-Said, O. S.; Alcisto, J.; Guerra, J.; Jones, E.; Dominguez, A.; Hahn, M.; Ula, N.; Zeng, L.; Ramsey, B.; Mulazimoglu, H.; Li, Yong-Jun; Miller, M.; Alrashid, J.; Papakyriakou, M.; Kalnaus, S.; Lee, E. W.; Frazier, W. E.

    2016-09-01

    Hydrogen was intentionally introduced into ultra-high strength steel by cadmium plating. The purpose was to examine the effect of cadmium plate thickness and hence hydrogen on the impact energy of the steel. The AISI 4340 steel was austenitized at 1000 °C for 1 h, water quenched, and tempered at temperatures between 257 and 593 °C in order to achieve a range of targeted strength levels. The specimens were cadmium plated with 0.00508 mm (0.2 mils), 0.00762 mm (0.3 mils), and 0.0127 mm (0.5 mils). Results demonstrated that the uncharged specimens exhibited higher impact energy values when compared to the plated specimens at all tempering temperatures. The cadmium-plated specimens had very low Charpy impact values irrespective of their ultimate tensile strength values. The model of hydrogen transport by mobile dislocations to the fracture site appears to provide the most suitable explanation of the results.

  17. Instrumented impact testing machine with reduced specimen oscillation effects

    Science.gov (United States)

    Rintamaa, R.; Ranka, K.; Wallin, K.; Ikonen, K.; Talja, H.; Kotilainen, H.; Sirkkola, E.

    1984-07-01

    A pendulum-type instrumented Charpy test apparatus based on inverted test geometry was developed. Geometry inversion reduces inertia load and specimen oscillation effects. Initial impact energy is double that of standard (300 J) impact testers, allowing the use of larger (10 x 20 x 110 mm) bend specimens than normal Charpy specimens. The rotation axis in the three point bending is nearly stationary, making COD-measurements possible. Inertia effects and specimen oscillations are compared with the conventional tester, and using an analytical finite element model for Charpy V-notch specimens. Better performance for the inverted geometry is reported.

  18. A reassessment of the effects of helium on Charpy impact properties of ferritic/martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Gelles, D.S.; Hamilton, M.L. [Pacific Northwest National Lab., Richland, WA (United States); Hankin, G.L. [Loughborough Univ. (United Kingdom)

    1998-03-01

    To test the effect of helium on Charpy impact properties of ferritic/martensitic steels, two approaches are reviewed: quantification of results of tests performed on specimens irradiated in reactors with very different neutron spectra, and isotopic tailoring experiments. Data analysis can show that if the differences in reactor response are indeed due to helium effects, then irradiation in a fusion machine at 400 C to 100 dpa and 1000 appm He will result in a ductile to brittle transition temperature shift of over 500 C. However, the response as a function of dose and helium level is unlikely to be simply due to helium based on physical reasoning. Shear punch tests and microstructural examinations also support this conclusion based on irradiated samples of a series of alloys made by adding various isotopes of nickel in order to vary the production of helium during irradiation in HFIR. The addition of nickel at any isotopic balance to the Fe-12Cr base alloy significantly increased the shear yield and maximum strengths of the alloys. However, helium itself, up to 75 appm at over 7 dpa appears to have little effect on the mechanical properties of the alloys. This behavior is instead understood to result from complex precipitation response. The database for effects of helium on embrittlement based on nickel additions is therefore probably misleading and experiments should be redesigned to avoid nickel precipitation.

  19. Application of Charpy Impact Absorbed Energy to the Safety Assessment Based on SINTAP

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The European Structural Integrity Assessment Procedure(SINTAP) was applied to the assessment of welded joints of the APl 5L X65 pipeline steel with an assumed embedded flaw and surface flaw at the weld toe. At default level( level 0), the assessment point was established by estimating fracture toughness value KIc conservatively from Charpy energy test data. At the same time, the analysis level 1 (basic level)was applied based on the fracture toughness CTOD. Then the two assessment levels were compared. The assessment results show that all assessment points are located within the failure lines of analysis levels 0 and 1. So the welded joint of the pipeline is safe. It can be concluded that the assessment based on Charpy absorbed energy is practicable when other fracture toughness data are not available, or cannot be easily obtained. The results are conservative.

  20. Effects of thermal aging on fracture toughness and Charpy-impact strength of stainless steel pipe welds

    Energy Technology Data Exchange (ETDEWEB)

    Gavenda, D.J.; Michaud, W.F.; Galvin, T.M.; Burke, W.F.; Chopra, O.K. [Argonne National Lab., IL (United States)

    1996-05-01

    Degradation of fracture toughness, tensile, and Charpy-impact properties of Type 304 and 304/308 SS pipe welds due to thermal aging was studied at room temperature and 290 C. Thermal aging of SS welds results in moderate decreases in charpy-impact strength and fracture toughness. Upper-shelf energy decreased by 50-80 J/cm{sup 2}. Decrease in fracture toughness J-R curve or J{sub IC} is relatively small. Thermal aging had no or little effect on tensile strength of the welds. Fracture properties of SS welds are controlled by the distribution and morphology of second-phase particles. Failure occurs by formation and growth of microvoids near hard inclusions; such processes are relatively insensitive to thermal aging. The ferrite phase has little or no effect on fracture properties of the welds. Differences in fracture resistance of the welds arise from differences in the density and size of inclusions. Mechanical-property data from the present study are consistent with results from other investigations. The existing data have been used to establish minimum expected fracture properties for SS welds.

  1. Standard test method for instrumented impact testing of metallic materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This standard establishes the requirements for performing instrumented Charpy V-Notch (CVN) and instrumented Miniaturized Charpy V-Notch (MCVN) impact tests on metallic materials. This method, which is based on experience developed testing steels, provides further information (in addition to the total absorbed energy) on the fracture behavior of the tested materials. Minimum requirements are given for measurement and recording equipment such that similar sensitivity and comparable total absorbed energy measurements to those obtained in Test Methods E 23 and E 2248 are achieved. 1.2 The values stated in SI units are to be regarded as the standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  2. Miniaturized Charpy test for reactor pressure vessel embrittlement characterization

    Energy Technology Data Exchange (ETDEWEB)

    Manahan, M.P. Sr. [MPM Research and Consulting, Lemont, PA (United States)

    1999-10-01

    Modifications were made to a conventional Charpy machine to accommodate the miniaturized Charpy V-Notch (MCVN) specimens which were fabricated from an archived reactor pressure vessel (RPV) steel. Over 100 dynamic MCVN tests were performed and compared to the results from conventional Charpy V-Notch (CVN) tests to demonstrate the efficacy of the miniature specimen test. The optimized sidegrooved MCVN specimens exhibit transitional fracture behavior over essentially the same temperature range as the CVN specimens which indicates that the stress fields in the MCVN specimens reasonably simulate those of the CVN specimens and this fact has been observed in finite element calculations. This result demonstrates a significant breakthrough since it is now possible to measure the ductile-brittle transition temperature (DBTT) using miniature specimens with only small correction factors, and for some materials as in the present study, without the need for any correction factor at all. This development simplifies data interpretation and will facilitate future regulatory acceptance. The non-sidegrooved specimens yield energy-temperature data which is significantly shifted downward in temperature (non-conservative) as a result of the loss of constraint which accompanies size reduction.

  3. Impact toughness of high strength low alloy TMT reinforcement ribbed bar

    Indian Academy of Sciences (India)

    Bimal Kumar Panigrahi; Surendra Kumar Jain

    2002-08-01

    Charpy V-notch impact toughness of 600 MPa yield stress TMT rebars alloyed with copper, phosphorus, chromium and molybdenum has been evaluated. Subsize Charpy specimens were machined from the rebar keeping the tempered martensite rim intact. The copper–phosphorus rebar showed toughness of 35 J at room temperature. The toughness of copper–molybdenum and copper–chromium rebars was 52 J. The lower toughness of phosphorus steel is attributed to solid solution strengthening and segregation of phosphorus to grain boundaries. Due to superior corrosion resistance, copper–phosphorus TMT rebar is a candidate material in the construction sector.

  4. Miniature Precracked Charpy Specimens for Measuring the Master Curve Reference Temperature of RPV Steels at Impact Loading Rates

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E.; Scibetta, M.; Puzzolante, L.

    2008-10-15

    In the framework of the 2006 Convention, we investigated the applicability of fatigue precracked miniature Charpy specimens of KLST type (MPCC - B = 3 mm, W = 4 mm and L = 27 mm) for impact toughness measurements, using the well-characterized JRQ RPV steel. In the ductile to-brittle transition region, MPCC tests analyzed using the Master Curve approach and compared to data previously obtained from PCC specimens had shown a more ductile behavior and therefore un conservative results. In the investigation presented in this report, two additional RPV steels have been used to compare the performance of impact-tested MPCC and PCC specimens in the transition regime: the low-toughness JSPS steel and the high-toughness 20MnMoNi55 steel. The results obtained (excellent agreement for 20MnMoNi55 and considerable differences between T0 values for JSPS) are contradictory and do not presently allow qualifying the MPCC specimens as a reliable alternative to PCC samples for impact toughness measurements.

  5. Charpy Impact Response of the Cracked Aluminum Plates Repaired with FML Patches using the Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Faramarz Ashenai Ghasemi

    2016-09-01

    Full Text Available Here, the effect of fiber metal laminate (FMLs patches was studied for repairing of single-sided cracked aluminum plates experimentally to see their response to Charpy impact tests. The main desired parameters were composite patch lay-up, crack length, and crack angle each one in three levels. All experimental attempts generated and followed based on the design of experiments method by using of response surface methodology. The predicted energy absorption values obtained from the model were in good agreement with the experimental results. No matter the specimens were repaired or not, as the crack length was increased the energy absorption of the structure was decreased. The experimental results also showed that for lengthen cracks, increasing of the crack angle had more effect on energy absorption. Also it was observed that the patch lay-up effective on the impact response of the specimens. The more the metal layer was departed from the aluminum plate and the FML patches interfacial surface, the less energy was absorbed in the structure.

  6. Low-energy charpy impact of interleaved CF/EP laminates

    Science.gov (United States)

    Yuan, Q.; Friedrich, K.; Karger-Kocsis, J.

    1995-03-01

    Carbon fiber (CF) reinforced epoxy (CF/EP) laminates laid up in different ways (cross-ply and quasi-isotropic) with and without various adhesive interlayers (A) were studied under three-point bending using instrumented low-energy impact at single and multiple bounces. Interleaves were a modified EP resin on polyester fabric, a modified EP resin, and a polyethersulphone (PES) film. The impact response depends strongly on whether the CFs are oriented longitudinally (L) or transversely (T) to the hammer edge in the outer bounced ply. The threshold incident energy ( E in,th) associated with severe damage to the laminates was much lower with the longitudinal outer ply. The impact fatigue response of the transverse cross-ply (TCP) and quasi-isotropic (TQI) composite beams showed that stiffness degradation starts at a certain a threshold number of impact (NOI) and follows a logarithmic decay as a function of NOI. This is in close analogy to fatigue tests under usual conditions. Deterioration in stiffness can be assigned to the relative change in the secant slope ( E max/ x max) of the load-displacement ( F-x) traces. The related load-time ( F-t) traces flatten due to impact fatigue so that their load maximum ( F max) shifts toward higher contact time. The efficiency of the interleaving was assessed in both single (at E in,th≈3 J) and repeated impact (at E in=1 J). The first technique allowed us to differentiate between the various interleaves, whereas the latter contributed to finding the optimum stacking and position of the interleaves.

  7. Charpy impact test results for low activation ferritic alloys irradiated to 30 dpa

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, L.E.; Hamilton, M.L.; Gelles, D.S. [Pacific Northwest National Laboratory, Richland, WA (United States)

    1996-04-01

    Miniature specimens of six low activation ferritic alloys have been impact field tested following irradiation at 370{degrees}C to 30 dpa. Comparison of the results with those of control specimens and specimens irradiated to 10 dpa indicates that degradation in the impact behavior appears to have saturated by {approx}10 dpa in at least four of these alloys. The 7.5Cr-2W alloy referred to as GA3X appears most promising for further consideration as a candidate structural material in fusion reactor applications, although the 9Cr-1V alloy may also warrant further investigation.

  8. Charpy impact test of Ti-6Al-4V joints diffusion welded at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, J.M.G. de; Urena, A. [Complutense Univ. of Madrid (Spain); Carrion, J.G. [National Inst. of Aeroespatial Technologies, Madrid (Spain). Materials and Structures Div.

    1996-08-15

    The Diffusion Welding (DW) of two or more sheets of Ti-6Al-4V alloy is particularly interesting for aerospace parts manufacturing. In some cases, DW can be carried out together with Superplastic Forming (SPF), because they can share a single facility and the same processing parameters, such as temperature, pressure, time, surface condition and vacuum. The overall manufacturing process is known as SPF/DW, by which it is possible to obtain honeycomb structures in a range of designs. Temperature requirements for industrial SPF of Ti-6Al-4V are very restrictive and a temperature of 1,023 K is needed. However, temperature is not so critical for DW, and the bond can be produced at lower temperatures, when other DW parameters, mainly pressure and time, are changed in a suitable way. The DW parameters for this research were chosen in order to produce DW joints below 1,023 K. The differences between DW at SPF temperatures and other lower temperatures would thus be revealed. Mechanical tests were used as a tool to check DW joints obtained at the temperatures used in the research (1,123 K and 1,023 K), and were complemented with metallographic studies. The results obtained form shear and peel tests have been already discussed. In the present work the results of impact energy tests are also presented.

  9. STRESS FIELD AT A TIP OF A PREFABRICATED SPIRAL V-NOTCH

    Institute of Scientific and Technical Information of China (English)

    郑周练; 陈山林; 叶晓明

    2004-01-01

    Based on the tranditional V-notched blasting,a technique of spirally V-notched blasting to loosen earth and rock was presented.Fracture mechanics and Westergaard stress function were adopted to build a complex stress function to derive the plane stress and strain fields at one tip of the crack under a quasi-static pressure.An expression was formulated to define the stress intensity factor of spiral V-notch loosen blasting.Factors that have effects on the stress intensity factor were studied.It is demonstrated that spiral V-notch loosen blasting is an extension of vertical V-notch blasting,straight cracking,and alike theories.

  10. Correlation between standard Charpy and sub-size Charpy test results of selected steels in upper shelf region

    Science.gov (United States)

    Konopík, P.; Džugan, J.; Bucki, T.; Rzepa, S.; Rund, M.; Procházka, R.

    2017-02-01

    Absorbed energy obtained from impact Charpy tests is one of the most important values in many applications, for example in residual lifetime assessment of components in service. Minimal absorbed energy is often the value crucial for extending components service life, e.g. turbines, boilers and steam lines. Using a portable electric discharge sampling equipment (EDSE), it is possible to sample experimental material non-destructively and subsequently produce mini-Charpy specimens. This paper presents a new approach in correlation from sub-size to standard Charpy test results.

  11. Impact resistance and fractography of low-alloy martensitic steels

    Directory of Open Access Journals (Sweden)

    S. Frydman

    2008-03-01

    Full Text Available In this paper dynamic properties of HTK SOOH, HTK 900H. Hardox 400 and Hardox 500 steeZs in delivcrcd stalc (aftcr hardening andtempering are considered. Charpy V - notch (CVN test rcsults in connection with fractography in the ductilc - to - brittle transitionternpcrature region were analyzed. The impact transition curve obtained from CVN tcst not always predicts properly a behavior ofmaterials in conditions of dynamic loading, so the analyze of character of fracture helps to evalitate the rcal bchavior of ma~crials. Tcstcdsamples were cut out longitudinally and transversely in relation to cold work direction. The results of CVN test far investigated steels, inthe range of temperatures from 40t o 20 "C are presented. Regarding ductilc - to - bri~tlel ransition temperature, there is a significantdiffcrcnce taking into account vatues of Charpy V cncrgy absorbcd and a character of fracture.

  12. Degradation of impact fracture during accelerated aging of weld metal on microalloyed steel; Degradacion de la tenacidad al impacto durante el envejecimiento acelerado de soldadura en acero microaleado

    Energy Technology Data Exchange (ETDEWEB)

    Vargas-Arista, B.; Hallen, J. M.; Albiter, A.; Angeles-Chavez, C.

    2008-07-01

    The effect of accelerated aging on the toughness and fracture of the longitudinal weld metal on an API5L-X52 line pipe steel was evaluated by Charpy V-notch impact test, fracture analysis and transmission electron microscopy. Aging was performed at 250 degree centigrade for 100 to 1000 h. The impact results indicated a significant reduction in the fracture energy and impact toughness as a function of aging time, which were achieved by the scanning electron microscope fractography that showed a decrease in the vol fraction of microvoids by Charpy ductile failure with the aging time, which favored the brittle fracture by transgranular cleavage. The minimum vol fraction of microvoids was reached at 500 h due to the peak aged. The microstructural analysis indicated the precipitation of transgranular iron nano carbides in the aged specimens, which was related to the deterioration of toughness and change in the ductile to brittle behavior. (Author) 15 refs.

  13. Numerical and experimental evaluation of the impact performance of advanced high-strength steel sheets based on a damage model

    Science.gov (United States)

    Ma, Ning; Park, Taejoon; Kim, Dongun; Kim, Chongmin; Chung, Kwansoo

    2010-06-01

    The impact performance in a Charpy impact test was experimentally and numerically studied for the advanced high-strength steel sheets (AHSS) TWIP940 and TRIP590 as well as the high-strength grade known as 340R. To characterize the mechanical properties, uni-axial simple tension tests were conducted to determine the anisotropic properties and strain rate sensitivities of these materials. In particular, the high-speed strain-rate sensitivity of TRIP590 and 340R (rate sensitive) was also characterized to account for the high strain rates involved in the Charpy impact test. To evaluate fracture behavior in the Charpy impact test, a new damage model including a triaxiality-dependent fracture criterion and hardening behavior with stiffness deterioration was introduced. The model was calibrated via numerical simulations and experiments involving simple tension and V-notch tests. The new damage model along with the anisotropic yield function Hill 1948 was incorporated into the ABAQUS/Explicit FEM code, which performed reasonably well to predict the impact energy absorbed during the Charpy impact test.

  14. Charpy impact test results of four low activation ferritic alloys irradiated at 370{degrees}C to 15 DPA

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, L.E.; Hamilton, M.L.; Gelles, D.S. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-10-01

    Miniature CVN specimens of four low activation ferritic alloys have been impact tested following irradiation at 370{degrees}C to 15 dpa. Comparison of the results with those of control specimens indicates that degradation in the impact behavior occurs in each of these four alloys. The 9Cr-2W alloy referred to as GA3X and the similar alloy F82H with 7.8Cr-2W appear most promising for further consideration as candidate structural materials in fusion energy system applications. These two alloys exhibit a small DBTT shift to higher temperatures but show increased absorbed energy on the upper shelf.

  15. Critical applied stresses for a crack initiation from a sharp V-notch

    Directory of Open Access Journals (Sweden)

    L. Náhlík

    2014-10-01

    Full Text Available The aim of the paper is to estimate a value of the critical applied stress for a crack initiation from a sharp V-notch tip. The classical approach of the linear elastic fracture mechanics (LELM was generalized, because the stress singularity exponent differs from 0.5 in the studied case. The value of the stress singularity exponent depends on the V-notch opening angle. The finite element method was used for a determination of stress distribution in the vicinity of the sharp V-notch tip and for the estimation of the generalized stress intensity factor depending on the V-notch opening angle. Critical value of the generalized stress intensity factor was obtained using stability criteria based on the opening stress component averaged over a critical distance d from the V-notch tip and generalized strain energy density factor. Calculated values of the critical applied stresses were compared with experimental data from the literature and applicability of the LEFM concept is discussed.

  16. Further Charpy impact test results of low activation ferritic alloys, irradiated at 430{degrees}C to 67 dpa

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, L.E.; Hamilton, M.L.; Gelles, D.S. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-04-01

    Miniature CVN specimens of four ferritic alloys, GA3X, F82H, GA4X and HT9, have been impact tested following irradiation at 430{degrees}C to 67 dpa. Comparison of the results with those of the previously tested lower dose irradiation condition indicates that the GA3X and F82H alloys, two primary candidate low activation alloys, exhibit virtually identical behavior following irradiation at 430{degrees}C to {approximately}67 dpa and at 370{degrees}C to {approximately}15 dpa. Very little shift is observed in either DBTT or USE relative to the unirradiated condition. The shifts in DBTT and USE observed in both GA4X and HT9 were smaller after irradiation at 430{degrees}C to {approximately}67 dpa than after irradiation at 370{degrees}C to {approximately}15 dpa.

  17. Impact Toughness of an Isothermally Treated Zeron®100 SDSS

    Science.gov (United States)

    Calliari, Irene; Breda, Marco; Ramous, Emilio; Brunelli, Katya; Pizzo, Marco; Menapace, Cinzia

    2012-10-01

    The aim of the present study is to investigate the impact toughness of a UNS 32760 SDSS, in relation to the quantity of secondary phases precipitated after isothermal aging in the range of 850-950 °C and for different exposure times. The impact toughness has been investigated by means of instrumented impact testing, using Charpy V-notched specimens at room temperature. The impact testing results show that, for an amount of about 0.5% volume fraction of intermetallic phase, the impact toughness is reduced by over 50%. For volume fractions higher than 1.5-2%, the impact toughness is definitively compromised, and small entities of plastic deformations are enough to cause a prevailing brittle fracture mechanism. By increasing the precipitates' amounts, the fracture mechanism shows an ever more prominent brittle behavior until 6% volume fraction, exceeding which the ductile component is totally absent.

  18. Impact Behavior of A356 Foundry Alloys in the Presence of Trace Elements Ni and V

    Science.gov (United States)

    Casari, Daniele; Ludwig, Thomas H.; Merlin, Mattia; Arnberg, Lars; Garagnani, Gian Luca

    2015-02-01

    In the present work, the impact behavior of unmodified A356 alloys with the addition of Ni or V in as-cast and T6 heat-treated conditions was assessed. Charpy V-notched specimens obtained from sand and permanent mold casting showed low total absorbed energy average values ( W t permanent mold cast alloys due to the locally finer microstructure. Concurrent mechanisms related to the chemical composition, solidification conditions and heat treatment were found to control the impact properties of the alloys. While the trace element Ni exerted only minor effects on the impact toughness of the A356 alloy, V had a strong influence: (i) V-containing sand cast alloys absorbed slightly higher impact energies compared to the corresponding A356 base alloys; (ii) in the permanent mold cast alloys, V in solid solution led to a considerable loss of ductility, which in turn decreased the total absorbed energy.

  19. Transferability of Charpy Absorbed Energy to Fracture Toughness Based on Weibull Stress Criterion

    Institute of Scientific and Technical Information of China (English)

    Hongyang JING; Lianyong XU; Lixing HUO; Fumiyoshi Minami

    2005-01-01

    The relationship between Charpy absorbed energy and the fracture toughness by means of the (crack tip opening displacement (CTOD)) method was analyzed based on the Weibull stress criterion. The Charpy absorbed energy and the fracture toughness were measured for the SN490B steel under the ductile-brittle transition temperature region. For the instrumented Charpy impact test, the curves between the loading point displacement and the load against time were recorded. The critical Weibull stress was taken as a fracture controlled parameter, and it could not be affected by the specimen configuration and the loading pattern based on the local approach. The parameters controlled brittle fracture are obtained from the Charpy absorbed energy results, then the fracture toughness for the compact tension (CT) specimen is predicted. It is found that the results predicted are in good agreement with the experimental. The fracture toughness could be evaluated by the Charpy absorbed energy, because the local approach gives a good description for the brittle fracture even though the Charpy impact specimen or the CT specimen is used for the given material.

  20. The effect of fibre content, fibre size and alkali treatment to Charpy impact resistance of Oil Palm fibre reinforced composite material

    Science.gov (United States)

    Fitri, Muhamad; Mahzan, Shahruddin

    2016-11-01

    In this research, the effect of fibre content, fibre size and alkali treatment to the impact resistance of the composite material have been investigated, The composite material employs oil palm fibre as the reinforcement material whereas the matrix used for the composite materials are polypropylene. The Oil Palm fibres are prepared for two conditions: alkali treated fibres and untreated fibres. The fibre sizes are varied in three sizes: 5mm, 7mm and 10mm. During the composite material preparation, the fibre contents also have been varied into 3 different percentages: 5%, 7% and 10%. The statistical approach is used to optimise the variation of specimen determined by using Taguchi method. The results were analyzed also by the Taguchi method and shows that the Oil Palm fibre content is significantly affect the impact resistance of the polymer matrix composite. However, the fibre size is moderately affecting the impact resistance, whereas the fibre treatment is insignificant to the impact resistance of the oil palm fibre reinforced polymer matrix composite.

  1. Study of crack propagation mechanisms during Charpy impact toughness tests on both equiaxed and lamellar microstructures of Ti–6Al–4V titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Buirette, Christophe, E-mail: christophe.buirette@ensiacet.fr [Institut Carnot CIRIMAT, ENSIACET, 4 allée Emile Monso, 31030 Toulouse (France); Huez, Julitte, E-mail: julitte.huez@ensiacet.fr [Institut Carnot CIRIMAT, ENSIACET, 4 allée Emile Monso, 31030 Toulouse (France); Gey, Nathalie, E-mail: Nathalie.gey@univ-lorraine.fr [Laboratoire d’Etude des Microstructures et de Mécanique des Matériaux (LEM3), UMR CNRS 7239, Université de Lorraine, Île du Saulcy, 57045 METZ Cedex 1 (France); DAMAS, Laboratory of Excellence on Design of Alloy Metals for Low-Mass Structures, Université de Lorraine (France); Vassel, Alain, E-mail: alain.vassel@titane.asso.fr [Association Française du Titane, 16 quai Ernest Renaud, BP 70515, 44105 Nantes Cedex 4 (France); Andrieu, Eric, E-mail: eric.andrieu@ensiacet.fr [Institut Carnot CIRIMAT, ENSIACET, 4 allée Emile Monso, 31030 Toulouse (France)

    2014-11-17

    The impact toughness of two highly textured rolled plates of Ti–6Al–4V alloy with an α equiaxed and an α lamellar microstructures has been investigated. The results show a strong anisotropy of the fracture energy for both materials and underline that a coincidence of the prismatic planes with the shear bands at the notch tip is favorable for higher fracture energies. Moreover, it is pointed out, as it was already done by previous studies, that the α lamellar microstructure presents higher fracture energy than the α equiaxed one. Thanks to electron back scattering diffraction, and tensile tests, local microstructure heterogeneities, called macrozones, have been observed and characterized. Their size depends on microstructure element and is larger for α lamellar microstructure than for the α equiaxed. High strain is localized on the macrozones favorably oriented for prismatic slip with respect to the direction of impact and leads to a particular dimple free zone on the fracture surface. The contribution of these macrozones in the fracture behavior, and more precisely on the crack propagation rate was evaluated; thus the effects of the macroscopic texture and of the microstructure element on the impact toughness are discussed separately.

  2. Effect of V Notch Shape on Fatigue Life in Steel Beam Made of AISI 1037

    Directory of Open Access Journals (Sweden)

    Qasim Bader

    2014-04-01

    Full Text Available The present work encompasses effect of V notch shape with various geometries and dimensions on fatigue life behavior in steel beam made of Medium Carbon Steel AISI 1037 which has a wide application in industry. Fatigue life of notched specimens is calculated using the fatigue life obtained from the experiments for smooth specimens (reference and by use Numerical method (FEA.The fatigue experiments were carried out at room temperature, applying a fully reversed cyclic load with the frequency of (50Hz and mean stress equal to zero (R= -1, on a cantilever rotating-bending fatigue testing machine. The stress ratio was kept constant throughout the experiment. Different instruments have been used in this investigation like Chemical composition analyzer type (Spectromax ,Tensile universal testing machine type (WDW-100E ,Hardness tester type (HSV- 1000 , Fatigue testing machine model Gunt WP 140, Optical Light Microscope (OLM and Scanning Electron Microscope (SEM were employed to examine the fracture features . The results show that there is acceptable error between experimental and numerical works .

  3. METHOD TO CALCULATE STRESS INTENSITY FACTOR OF V-NOTCH IN BI-MATERIALS

    Institute of Scientific and Technical Information of China (English)

    Youtang Li; Ming Song

    2008-01-01

    Based on Zak's stress function,the eigen-equation of stress singularity of bi-materials with a Ⅴ-notch was obtained.A new definition of stress intensity factor for a perpendicular inter facial Ⅴ-notch of bi-material was put forward.The effects of shear modulus and Poisson's ratio of the matrix material and attaching material on eigen-values were analyzed.A generalized ex pression for calculating KI of the perpendicular V-notch of bi-materials was obtained by means of stress extrapolation.Effects of notch depth,notch angle and Poisson's ratio of materials on the singular stress field near the tip of the Ⅴ-notch were analyzed systematically with numerical simulations.As an example,a finite plate with double edge notches under uniaxial uniform ten sion was calculated by the method presented and the influence of the notch angle and Poisson's ratio on the stress singularity near the tip of notch was obtained.

  4. INFLUENCE OF COOLING RATE DURING QUENCHING ON IMPACT TOUGHNESS OF A HOT-WORK TOOL STEEL AT AMBIENT TEMPERATURE AND AT 200 °C

    Directory of Open Access Journals (Sweden)

    Henrik Jesperson

    2013-05-01

    Full Text Available Gross cracking of die-casting dies with inferior toughness sometimes occurs through too low preheating temperature and/or too slow cooling during quenching. This study aimed to clarify the influence of cooling rate on the toughness of the hot-work tool steel grade Uddeholm Vidar Superior at ambient temperature and at 200 °C, a typical preheating temperature for aluminium die-casting dies. Toughness was measured through instrumented Charpy V-notch impact testing. The decrease in energy absorption with increasing cooling time between 800°C and 500°C both at both ambient temperature and 200 °C was pronounced. At ambient temperature, the decrease in total energy was a consequence of a decrease in initiation energy whereas, at 200 °C, the decrease in total energy was due to a decrease in propagation energy.

  5. Charpy V, an application in Mat lab; Charpy V, una aplicacion en Matlab

    Energy Technology Data Exchange (ETDEWEB)

    Castillo M, J.A.; Torres V, M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2003-07-01

    The obtained results with the system Charpy V{sub V}1 designed in Mat lab for the estimate of parameters of three mathematical models are shown. The adjustment of data is used to determine the fracture energy, the lateral expansion and the percentage of ductility of steels coming from the reactor vessels of Laguna Verde, Veracruz. The data come from test tubes type Charpy V of irradiated material and not irradiated. To verify our results they were compared with those obtained by General Electric of data coming from the Laguna Verde nuclear power plant. (Author)

  6. Fracture Mechanics Study on 155 mm M107E1 Projectile Made from Isothermally Transformed HF-1 Steel

    Science.gov (United States)

    1976-02-01

    of MIO7EI Projectiles.. 22 4. Charpy V-Notch Impact Energy of Tsothermally Transformed HF-i Steel (Heat A) as a Function of Testing Temperature . 23...evaluating rough handling. Specific stress and loading rate data were developed through a series of drop tests of instrumented projectiles. Although the...Impact Toughness The impact toughness of Heat A was investigated at test tempera- tures ranging from -65 degrees F to +1150 degrees F using Charpy V- notch

  7. A Calibration of the Wierzbicki-Xue Damage Model Using Charpy Test Results

    Directory of Open Access Journals (Sweden)

    Kim Jong-Bong

    2015-01-01

    Full Text Available Damage models are frequently used to predict fractures in large deformation problems such as penetration of a projectile into a target. Though many damage models have been proposed so far, coefficients of each model have been provided for only a few materials. In this study, the coefficients of the Wierzbicki-Xue (2005 damage model for tungsten heavy alloy (DX2HCMF are determined using the Charpy impact test. The Wierzbicki-Xue fracture criterion is implemented into NET3D code in which a node-split algorithm is built in. By comparing the energy absorbed in the Charpy test with the results of finite element analysis, the fracture model coefficients are determined.

  8. On the Effectiveness of the Dynamic Force Adjustment for Reducing the Scatter of Instrumented Charpy Results

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E.

    2008-09-15

    One of the key factors for obtaining reliable instrumented Charpy results is the calibration of the instrumented striker. An interesting alternative to the conventional static calibration recommended by the standards is the Dynamic Force Adjustment (DFA), in which forces and displacements are iteratively adjusted until equality is achieved between absorbed energies calculated under the test record (Wt) and measured by the machine encoder (KV). In this study, this procedure has been applied to the instrumented data obtained by 10 international laboratories using notched and precracked Charpy specimens, in the framework of a Coordinated Research Project (CRP8) of IAEA. DFA is extremely effective in reducing the between-laboratory scatter for both general yield and maximum forces. The effect is less significant for dynamic reference temperatures measured from precracked Charpy specimens using the Master Curve procedure, but a moderate reduction of the standard deviation is anyway observed. It is shown that striker calibration is a prominent contribution to the interlaboratory variability of instrumented impact forces, particularly in the case of maximum forces.

  9. Evaluation of fracture toughness in dental ceramics using indentation and SEVNB (Single Edge V-Notched Beam)-method; Avaliacao da tenacidade a fratura de ceramicas dentarias atraves do metodo de entalhe - SEVNB (Single Edge V-Notched Beam)

    Energy Technology Data Exchange (ETDEWEB)

    Santos, L.A.; Santos, C.; Souza, R.C.; Ribeiro, S. [Universidade de Sao Paulo (DEMAR/EEL/USP), Lorena, SP (Brazil). Escola de Engenharia de Lorena. Dept. de Engenharia de Materiais. Polo Urbo-Industrial; Strecker, K. [Universidade Federal de Sao Joao del-Rei (DME/UFSJ), MG (Brazil). Dept. de Materiais Eletricos; Oberacker, R. [Karlsruhe Univ. (Germany)

    2009-07-01

    In this work, the fracture toughness of different ceramics based on Al{sub 2}O{sub 3} and ZrO{sub 2} were evaluated using, comparatively two methods, Vickers indentation and SEVNB (Single Edge V-Notched Beam) method. Al{sub 2}O{sub 3}, ZrO{sub 2}(3%Y{sub 2}O{sub 3}) micro-particled and ZrO{sub 2}(3%Y{sub 2}O{sub 3}) nanometric, ZrO{sub 2}-Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}-ZrO{sub 2} composites were sintered at different temperatures. Samples were characterized by relative density, X-ray diffraction, SEM, and mechanical evaluation by hardness, bending strength and fracture toughness obtained by ickers indentation and SEVNB-method. The results were presented comparing the densification and microstructural results. Furthermore, the advantages and limitations of each method were discussed. (author)

  10. Correlations between Standard and Miniaturised Charpy-V Specimens

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E.; Van Walle, E.; Fabry, A.; Puzzolante, J.-L.; Verstrepen, A.; Vosch, R.; Van de Velde, L

    1998-12-01

    A total of 565 instrumented impact tests (232 performed on full-size and 333 on sub-size Charpy-V specimens) have been analysed in order to derive meaningful assumptions on the correlations existing between test results obtained on specimens of different size. Nine materials (pressure vessel steels) have been considered, in both as-received and irradiated state, for a total of 19 conditions examined. For the analysis of data, conventional as well novel approaches have been investigated; former ones, based on a review of the existing literature, include predictions of USE values by the use of normalization factors (NF), shifts of index temperatures related to energy/lateral expansion/shear fracture levels, and a combination of both approaches (scaling and shifting of energy curves). More original and recent proposals have also been verified, available in the literature but also proposed by SCK-CEN in the frame of enhanced surveillance of nuclear reactor pressure vessels. Conclusions have been drawn regarding the applicability and reliability of these methodologies, and recommendations have been given for future developments of the activities on this topic.

  11. Influence of Striking Edge Radius (2 mm versus 8 mm) on Instrumented Charpy Data and Absorbed Energies

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E.

    2008-08-15

    The most commonly used test standards for performing Charpy impact tests (ISO 148 and ASTM E 23) envisage the use of strikers having different radii of the striking edge, i.e. 2 mm (ISO) and 8 mm (ASTM). The effect of striker geometry on Charpy results was extensively studied in the past in terms of absorbed energy measured by the machine encoder, but few investigations are available on the influence of striker configuration on the results of instrumented Charpy tests (characteristic forces, displacements and integrated energy). In this paper, these effects are investigated based on the analysis of published results from three interlaboratory studies and some unpublished Charpy data obtained at SCK-CEN. The instrumented variables which are the most sensitive to the radius of the striking edge are the maximum force and its corresponding displacement, with 8mm-strikers providing systematically higher values. Absorbed energies, obtained both from the instrumented trace and from the pendulum encoder, are almost insensitive to the type of striker up to 200 J. For higher energy levels, the values obtained from 8mm strikers become progressively larger. Data scatter is generally higher for 2mm-strikers.

  12. Impact Toughness Properties of Nickel- and Manganese-Free High Nitrogen Austenitic Stainless Steels

    Science.gov (United States)

    Mohammadzadeh, Roghayeh; Akbari, Alireza; Mohammadzadeh, Mina

    2016-12-01

    A large amount of manganese (>10 wt pct) in nickel-free high nitrogen austenitic stainless steels (Ni-free HNASSs) can induce toxicity. In order to develop Ni-free HNASSs with low or no manganese, it is necessary to investigate their mechanical properties for biomedical applications. This work aims to study the Charpy V-notch (CVN) impact toughness properties of a Ni- and Mn-free Fe-22.7Cr-2.4Mo-1.2N HNASS plate in the temperature range of 103 K to 423 K (-170 °C to 150 °C). The results show that unlike conventional AISI 316L austenitic stainless steel, the Ni- and Mn-free HNASS exhibits a sharp ductile-to-brittle transition (DBT). The intergranular brittle fracture associated with some plasticity and deformation bands is observed on the fracture surface at 298 K (25 °C). Electron backscattered diffraction (EBSD) analysis of the impact-tested sample in the longitudinal direction indicates that deformation bands are parallel to {111} slip planes. By decreasing the temperature to 273 K, 263 K, and 103 K (0 °C, -10 °C, and -70 °C), entirely intergranular brittle fracture occurs on the fracture surface. The fracture mode changes from brittle fracture to ductile as the temperature increases to 423 K (150 °C). The decrease in impact toughness is discussed on the basis of temperature sensitivity of plastic flow and planarity of deformation mechanism.

  13. Certification of NIST Room Temperature Low-Energy and High-Energy Charpy Verification Specimens.

    Science.gov (United States)

    Lucon, Enrico; McCowan, Chris N; Santoyo, Ray L

    2015-01-01

    The possibility for NIST to certify Charpy reference specimens for testing at room temperature (21 °C ± 1 °C) instead of -40 °C was investigated by performing 130 room-temperature tests from five low-energy and four high-energy lots of steel on the three master Charpy machines located in Boulder, CO. The statistical analyses performed show that in most cases the variability of results (i.e., the experimental scatter) is reduced when testing at room temperature. For eight out of the nine lots considered, the observed variability was lower at 21 °C than at -40 °C. The results of this study will allow NIST to satisfy requests for room-temperature Charpy verification specimens that have been received from customers for several years: testing at 21 °C removes from the verification process the operator's skill in transferring the specimen in a timely fashion from the cooling bath to the impact position, and puts the focus back on the machine performance. For NIST, it also reduces the time and cost for certifying new verification lots. For one of the low-energy lots tested with a C-shaped hammer, we experienced two specimens jamming, which yielded unusually high values of absorbed energy. For both specimens, the signs of jamming were clearly visible. For all the low-energy lots investigated, jamming is slightly more likely to occur at 21 °C than at -40 °C, since at room temperature low-energy samples tend to remain in the test area after impact rather than exiting in the opposite direction of the pendulum swing. In the evaluation of a verification set, any jammed specimen should be removed from the analyses.

  14. Tensile and impact properties of V-4Cr-4Ti alloy heats 832665 and 832864.

    Energy Technology Data Exchange (ETDEWEB)

    Bray, T. S.; Tsai, H.; Nowicki, L. J.; Billone, M. C.; Smith, D. L.; Johnson, W. R.; Trester, P. W.

    1999-11-08

    Two large heats of V-4Cr-4Ti alloy were produced in the United States in the past few years. The first, 832665, was a 500 kg heat procured by the U.S. Department of Energy for basic fusion structural materials research. The second, 832864, was a 1300 kg heat procured by General Atomics for the DIII-D radiative divertor upgrade. Both heats were produced by Oremet-Wah Chang (previously Teledyne Wah Chang of Albany). Tensile properties up to 800 C and Charpy V-notch impact properties down to liquid nitrogen temperature were measured for both heats. The product forms tested for both heats were rolled sheets annealed at 1000 C for 1 h in vacuum. Testing results show the behavior of the two heats to be similar and the reduction of strengths with temperature to be insignificant up to at least 750 C. Ductility of both materials is good in the test temperature range. Impact properties for both heats are excellent--no brittle failures at temperatures above -150 C. Compared to the data for previous smaller laboratory heats of 15-50 kg, the results show that scale-up of vanadium alloy ingot production to sizes useful for reactor blanket design can be successfully achieved as long as reasonable process control is implemented.

  15. Effects of Notch Misalignment and Tip Radius on Displacement Field in V-Notch Rail Shear Test as Determined by Photogrammetry

    Science.gov (United States)

    Hill, Charles S.; Oliveras, Ovidio M.

    2011-01-01

    Evolution of the 3D strain field during ASTM-D-7078 v-notch rail shear tests on 8-ply quasi-isotropic carbon fiber/epoxy laminates was determined by optical photogrammetry using an ARAMIS system. Specimens having non-optimal geometry and minor discrepancies in dimensional tolerances were shown to display non-symmetry and/or stress concentration in the vicinity of the notch relative to a specimen meeting the requirements of the standard, but resulting shear strength and modulus values remained within acceptable bounds of standard deviation. Based on these results, and reported difficulty machining specimens to the required tolerances using available methods, it is suggested that a parametric study combining analytical methods and experiment may provide rationale to increase the tolerances on some specimen dimensions, reducing machining costs, increasing the proportion of acceptable results, and enabling a wider adoption of the test method.

  16. Fractographic examination of reduced activation ferritic/martensitic steel charpy specimens irradiated to 30 dpa at 370{degrees}C

    Energy Technology Data Exchange (ETDEWEB)

    Gelles, D.S.; Hamilton, M.L. [Pacific Northwest National Lab., Richland, WA (United States); Schubert, L.E. [Univ. of Missouri, Rolla, MO (United States)

    1996-10-01

    Fractographic examinations are reported for a series of reduced activation ferritic/Martensitic steel Charpy impact specimens tested following irradiation to 30 dpa at 370{degrees}C in FFTF. One-third size specimens of six low activation steels developed for potential application as structural materials in fusion reactors were examined. A shift in brittle fracture appearance from cleavage to grain boundary failure was noted with increasing manganese content. The results are interpreted in light of transmutation induced composition changes in a fusion environment.

  17. Investigation of some problems in developing standards for precracked Charpy slow bend tests

    Science.gov (United States)

    Succop, G.; Bubsey, R. T.; Jones, M. H.; Brown, W. F., Jr.

    1977-01-01

    The reported investigation was undertaken in connection with an attempt to develop procedures which would be useful in standardizing a test method for the precracked Charpy slow bend specimen. A number of alloys was studied for which valid plane-strain fracture toughness values have been established. The investigation shows that useful relations between precracked Charpy slow bend results and crack size factors can be obtained under some circumstances. However, it is not yet known what factors control these circumstances.

  18. Standard Guide for Reconstitution of Irradiated Charpy-Sized Specimens

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This guide covers procedures for the reconstitution of ferritic pressure boundary steels used in nuclear power plant applications, Type A Charpy (Test Methods E 23) specimens and specimens suitable for testing in three point bending in accordance with Test Methods E 1921 or E 1820. Materials from irradiation programs (principally broken specimens) are reconstituted by welding end tabs of similar material onto remachined specimen sections that were unaffected by the initial test. Guidelines are given for the selection of suitable specimen halves and end tab materials, for dimensional control, and for avoidance of overheating the notch area. A comprehensive overview of the reconstitution methodologies can be found in Ref (1). 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard...

  19. Tensile and impact properties of V-4Cr-4Ti alloy heats 832665 and 832864

    Energy Technology Data Exchange (ETDEWEB)

    Bray, T.S. E-mail: tbray@anl.gov; Tsai, H.; Nowicki, L.J.; Billone, M.C.; Smith, D.L.; Johnson, W.R.; Trester, P.W

    2000-12-01

    Two large heats of V-4Cr-4Ti alloy were produced in the US in the past few years. The first, 832665, was a 500 kg heat procured by the US Department of Energy for basic fusion structural materials research. The second, 832864, was a 1300 kg heat procured by General Atomics for the DIII-D radiative divertor upgrade. Both heats were produced by Oremet-Wah Chang (previously Teledyne Wah Chang of Albany). Tensile properties up to 800 deg. C and Charpy V-notch impact properties down to liquid nitrogen temperature were measured for both heats. The product forms tested for both heats were rolled sheets annealed at 1000 deg. C for 1 h in vacuum. Testing results show the behavior of the two heats to be similar and the reduction of strengths with temperature to be insignificant up to at least 750 deg. C. Ductility of both materials is good in the test temperature range. Impact properties for both heats are excellent - no brittle failures at temperatures above -150 deg. C. Compared to the data for previous smaller laboratory heats of 15-50 kg, the results show that scale-up of vanadium alloy ingot production to sizes useful for reactor blanket design can be successfully achieved as long as reasonable process control is implemented (H. Tsai, et al., Fusion Materials Semiannual Progress Report for Period Ending 30th June 1998, DOE/ER-0313/24, p. 3; H. Tsai, et al., Fusion Materials Semiannual Progress Report for Period Ending 31st December 1998, DOE/ER-0313/25, p. 3)

  20. EUROFER 97. Tensile, charpy, creep and structural tests

    Energy Technology Data Exchange (ETDEWEB)

    Rieth, M.; Schirra, M.; Falkenstein, A.; Graf, P.; Heger, S.; Kempe, H.; Lindau, R.; Zimmermann, H.

    2003-10-01

    EUROFER 97 - the European reference material for the first wall of a DEMO fusion reactor - was produced as 3.5 t batch of rods and plates. Following the history of the development activities from conventional martensitic 12% Cr steel, MANET and OPTIFER up to the low or reduced activation (RAFM) EUROFER steel, results obtained from experiments on specimens from rods (diameter 100 mm) and plates (14 mm) are presented for a basic characterization. Physical and mechanical properties are compared with those of OPTIFER-1W and the F82H-mod 2% W steel. The transition behaviour was determined by plotting a continuous TTT (time temperature transition) diagram. In addition, extension coefficients were determined from room temperature up to 1000 C. Hardening tests at temperatures from 850 C to 1120 C illustrated the range of maximum hardness as well as grain size development. Tempering tests and additional annealing experiments from 300 C to 875 C allowed characterizing tempering behaviour and stability. Charpy properties were examined for various heat treatments and specimen types between 60 C and -100 C. Further, ductility criteria like FATT, DBTT and 68 J were determined. Particular attention was paid to the influence of grain size and O{sub 2} content. Tensile strength was measured for several heat treatments between room temperature and 700 C. Long-term ageing was investigated by means of stabilization annealing experiments. These were carried out with various temperature/time combinations including tensile tests. In EUROFER tensile strength was hardly affected by the different heat treatments while the ductility criteria showed only a moderate increase in temperature. Therefore, it can be concluded that EUROFER is not susceptible to ageing. Creep and creep rupture properties were investigated in the temperature range of 450 C to 650 C. So far, creep times of up to 15000 h have been covered by the experiments. The status of the test program allows for an extrapolation of

  1. Instrumented Charpy Impact Testing and Dynamic Fracture Toughness of 30CrNi2MoV Steel of Frac-pump Fluid Cylinder%压裂泵阀箱用钢的示波冲击性能及动态断裂韧性

    Institute of Scientific and Technical Information of China (English)

    王国荣; 陈林燕; 肖晓华; 李蓉

    2014-01-01

    对30CrNi2MoV压裂泵阀箱用钢进行880℃淬火+560~650℃回火的调质处理,在室温下进行了CharpyV型缺口示波冲击试验,通过SEM对各个回火温度下的冲击断口形貌进行了对比分析.实验结果表明:30CrNi2MoV阀箱钢的延性断裂韧度、动态断裂韧度、裂纹扩展功、冲击功等关键指标均随回火温度的升高而升高.供货态试样断口为解理形貌;560℃回火断口形貌是准解理+韧窝;590~650℃断口是韧窝形貌.冲击韧度和冲击断口形貌有良好的对应关系.

  2. Evaluation of hydrogen embrittlement and temper embrittlement by key curve method in instrumented Charpy test

    Directory of Open Access Journals (Sweden)

    Makita A.

    2010-06-01

    Full Text Available Instrumented Charpy test was conducted on small sized specimen of 21/4Cr-1Mo steel. In the test the single specimen key curve method was applied to determine the value of fracture toughness for the initiation of crack extension with hydrogen free, KIC, and for hydrogen embrittlement cracking, KIH. Also the tearing modulus as a parameter for resistance to crack extension was determined. The role of these parameters was discussed at an upper shelf temperature and at a transition temperature. Then the key curve method combined with instrumented Charpy test was proven to be used to evaluate not only temper embrittlement but also hydrogen embrittlement.

  3. Certification of NIST Room Temperature Low-Energy and High-Energy Charpy Verification Specimens

    OpenAIRE

    Lucon, Enrico; McCowan, Chris N.; Santoyo, Ray L.

    2015-01-01

    The possibility for NIST to certify Charpy reference specimens for testing at room temperature (21 °C ± 1 °C) instead of −40 °C was investigated by performing 130 room-temperature tests from five low-energy and four high-energy lots of steel on the three master Charpy machines located in Boulder, CO. The statistical analyses performed show that in most cases the variability of results (i.e., the experimental scatter) is reduced when testing at room temperature. For eight out of the nine lots ...

  4. Evaluation of hydrogen embrittlement and temper embrittlement by key curve method in instrumented Charpy test

    Science.gov (United States)

    Ohtsuka, N.; Shindo, Y.; Makita, A.

    2010-06-01

    Instrumented Charpy test was conducted on small sized specimen of 21/4Cr-1Mo steel. In the test the single specimen key curve method was applied to determine the value of fracture toughness for the initiation of crack extension with hydrogen free, KIC, and for hydrogen embrittlement cracking, KIH. Also the tearing modulus as a parameter for resistance to crack extension was determined. The role of these parameters was discussed at an upper shelf temperature and at a transition temperature. Then the key curve method combined with instrumented Charpy test was proven to be used to evaluate not only temper embrittlement but also hydrogen embrittlement.

  5. Instrumentação de um pendulo para ensaio de impacto Charpy

    OpenAIRE

    1994-01-01

    Resumo: O ensaio de impacto Charpy convencional, possibilita que se determine a energia total ('E IND. T') absorvida para fratura de um corpo de prova entalhado, de dimensões padronizadas. Entretanto, sabe-se que essa energia total, resulta da soma de duas componentes: a energia necessária para iniciar a fratura ('E IND.I') mais a energia necessária para a propagação dessa fratura ('E IND. P'). No presente trabalho, é instrumentado um pêndulo de ensaio de impacto Charpy, utilizando-se técnica...

  6. Visual interface for the automation of the instrumented pendulum of Charpy tests used in the surveillance program of reactors vessel of nuclear power plants; Interfase visual para la automatizacion del pendulo instrumentado de pruebas Charpy utilizado en el programa de vigilancia de la vasija de reactores de centrales nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Rojas S, A.S.; Sainz M, E.; Ruiz E, J.A. [ININ, Carretera Mexico-Toluca Km.36.5, Mpio. de Ocoyoacac, Estado de Mexico (Mexico)]. E-mail: asrs@nuclear.inin.mx; esm@nuclear.inin.mx; jare@nuclear.inin.mx

    2004-07-01

    Inside the Programs of Surveillance of the nuclear power stations periodic information is required on the state that keep the materials with those that builds the vessel of the reactor. This information is obtained through some samples or test tubes that are introduced inside the core of the reactor and it is observed if its physical characteristics remain after having been subjected to the radiation changes and temperature. The rehearsal with the instrumented Charpy pendulum offers information on the behavior of fracture dynamics of a material. In the National Institute of Nuclear Research (ININ) it has an instrumented Charpy pendulum. The operation of this instrument is manual, having inconveniences to carry out rehearsals with radioactive material, handling of high and low temperatures, to fulfill the normative ones for the realization of the rehearsals, etc. In this work the development of a computational program is presented (virtual instrument), for the automation of the instrumented pendulum. The system has modules like: Card of data acquisition, signal processing, positioning system, tempered system, pneumatic system, compute programs like it is the visual interface for the operation of the instrumented Charpy pendulum and the acquisition of impact signals. This system shows that given the characteristics of the nuclear industry with radioactive environments, the virtual instrumentation and the automation of processes can contribute to diminish the risks to the personnel occupationally exposed. (Author)

  7. Impact properties of A356-T6 alloys

    Science.gov (United States)

    Shivkumar, S.; Wang, L.; Keller, C.

    1994-02-01

    The Charpy impact energy of A356 alloys has been measured. Instrumented Charpy impact tests have been conducted at 25,100,150, and 200 °C. The Charpy specimens were machined from plate castings ortapered cylindrical castings. The plates were produced in sand molds, and tapered cylinders were produced in water-cooled copper molds. Both unmodified and strontium-modified castings were tested. The results indicate that strontium modification improves the impact properties of sand and permanent mold castings. The impact energy increases with solution treatment time. Strontium modification reduces the solution treatment time for attaining a specific impact property level in the casting.

  8. Instrumented Impact Testing Using a Hopkinson Bar Apparatus

    Science.gov (United States)

    1975-07-01

    revert« «Id» II necnnvv *nd identity by ftfoeft number) A technique for conducting instrumented Charpy impact tests using a Hopkin- son bar is...materi- al--; obtained from an instrumented impact test at 54 in/sec (1.37 m/s) and from a standard Charpy impact machine at 135 in/sec (3.43 m/s...arises as to how important wave reflections might be in the interpretation of experimental data from an instrumented Charpy impact test . In

  9. Identification of neutron irradiation induced strain rate sensitivity change using inverse FEM analysis of Charpy test

    Science.gov (United States)

    Haušild, Petr; Materna, Aleš; Kytka, Miloš

    2015-04-01

    A simple methodology how to obtain additional information about the mechanical behaviour of neutron-irradiated WWER 440 reactor pressure vessel steel was developed. Using inverse identification, the instrumented Charpy test data records were compared with the finite element computations in order to estimate the strain rate sensitivity of 15Ch2MFA steel irradiated with different neutron fluences. The results are interpreted in terms of activation volume change.

  10. Apportion of Charpy energy in API 5L grade X70 pipeline steel

    Energy Technology Data Exchange (ETDEWEB)

    Hashemi, Sayyed H. [Department of Mechanical Engineering, The University of Birjand, PO Box 97175 /615, Birjand (Iran, Islamic Republic of)], E-mail: shhashemi@birjand.ac.ir

    2008-12-15

    Conventional Charpy based failure models for gas transportation pipelines recommend the minimum fracture energy for safe performance of these structures. In recent years however, full-scale burst experiments have shown that such models cannot fully guarantee the safety of higher grade pipeline steels. One possible reason for this discrepancy, which is further investigated in this research, is that Charpy energy inherently contains both fracture and non-fracture related energy. To separate this, energy partitioning analysis was used. First, the overall fracture energy of X70 steel is measured experimentally on an instrumented Charpy rig. Next, the measured energy is divided into fracture initiation and propagation parts using load-displacement data. It appeared from test results that a significant amount of energy was consumed in non-fracture related processes. From this, correction factors were suggested for possible use in current industry failure models. Interestingly, these corrections factors agreed well with those reported from full-thickness burst tests for tough pipeline steels.

  11. Low temperature impact testing of welded structural wrought iron

    Science.gov (United States)

    Rogers, Zachary

    During the second half of the 19th century, structural wrought iron was commonly used in construction of bridges and other structures. Today, these remaining structures are still actively in use and may fall under the protection of historic preservation agencies. Continued use and protection leads to the need for inspection, maintenance, and repair of the wrought iron within these structures. Welding can be useful to achieve the appropriate repair, rehabilitation, or replacement of wrought iron members. There is currently very little published on modern welding techniques for historic wrought iron. There is also no pre-qualified method for this welding. The demand for welding in the repair of historic structural wrought iron has led to a line of research investigating shielded metal arc welding (SMAW) of historic wrought iron at the University of Colorado Denver. This prior research selected the weld type and other weld specifications to try and achieve a recognized specific welding procedure using modern SMAW technology and techniques. This thesis continues investigating SMAW of historic wrought iron. Specifically, this thesis addresses the toughness of these welds from analysis of the data collected from performing Charpy V-Notch (CVN) Impact Tests. Temperature was varied to observe the material response of the welds at low temperature. The wrought iron used in testing was from a historic vehicle bridge in Minnesota, USA. This area, and many other areas with wrought iron structures, can experience sustained or fluctuating temperatures far below freezing. Investigating the toughness of welds in historic wrought iron at these temperatures is necessary to fully understand material responses of the existing structures in need of maintenance and repair. It was shown that welded wrought iron is tougher and more ductile than non-welded wrought iron. In regards to toughness, welding is an acceptable repair method. Information on wrought iron, low temperature failure

  12. Influence of Loading Rate on the Calibration of Instrumented Charpy Strikers

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E.; Scibetta, M.; McColskey, D.; McCowan, C.

    2009-01-15

    One of the key factors for obtaining reliable instrumented Charpy results is the calibration of the instrumented striker. The conventional approach for establishing an analytical relationship between strain gage output and force applied to the transducer is the static calibration, which is preferably performed with the striker installed in the pendulum assembly. However, the response of an instrumented striker under static force application may sometimes differ significantly from its dynamic performance during an actual Charpy test. This is typically reflected in a large difference between absorbed energy returned by the pendulum encoder (KV) and calculated under the instrumented force/displacement test record (Wt). Such difference can be either minimized by optimizing the striker design or analytically removed by adjusting forces and displacements until KV = Wt (the so-called 'Dynamic Force Adjustment'). This study investigates the influence of increasing force application rates on the force/voltage characteristics of two instrumented strikers, one at NIST in Boulder, CO and one at SCK-CEN in Mol, Belgium.

  13. On the Use of the Master Curve based on the Precracked Charpy Specimen

    Energy Technology Data Exchange (ETDEWEB)

    Chaouadi, R.; Scibetta, M.; Van Walle, E.; Gerard, R

    1999-08-01

    Recently, worldwide interest has been demonstrated in the evaluation of the use of the Master Curve approach to characterize fracture toughness of ferritic steels in the transition regime. This was acknowledged by the recent release of the ASTM Standard Test Method for Determination of Reference Temperature, T{sub 0}, for Ferritic Steels in the Transition Range (E1921). The present work aims to investigate the use of the Charpy specimen along with the Master Curve approach to derive the fracture toughness behaviour of reactor pressure vessel steels. Therefore, four well characterized and documented reactor pressure vessel steels were selected. A large experimental program to measure fracture toughness with Charpy size specimens was carried out. Four important aspects were investigated: (1) the T0 determination as a function of test temperature; (2) the E1921 specimen size requirement (factor M=30); (3) the censoring procedure for specimens not satisfying the E1921 size requirements; (4) the estimation of the fracture toughness lower bound, and its comparison to the ASME KIC curve. It is found that within the experimental and statistical uncertainties, the reference temperature T0 is not affected by the test temperature, even when data are not valid according to E1921 requirements. By application of the censoring procedure, the determination of the reference temperature may lead to non conservative results. Comparison to larger specimen size suggests the use of M=60 rather than 30 to limit the loss of constraint, in agreement with finite element calculations. Nevertheless, the differences are not large enough to be statistically significant. The lower bound based on the Master Curve is very close to the experimental lower bound, while the ASME K{sub IC} curve trends to be over conservative. Replacing RT{sub NDT} by the new index, RT{sub To}, in the ASME KIC equation reduces this over conservatism.

  14. Development of an Ultralight Pulse Gas Metal ARC Welding System for Shipyard Applications

    Science.gov (United States)

    2007-07-27

    standard 200A OXO, Model AP20. Instrumentation included a calibrated analog ammeter (shunt, mV meter) and VOM (Simpson 260). Initial testing used...strength predicted based on the same correlation. In both cases, weld metal Charpy V-notch impact test results far exceeded minimum specification...Technology (CNST), work was conducted to specify, build, test , and production prove a light-weight, man-portable welding system as described above. The

  15. Fracture process of a low carbon low alloy steel relevant to charpy toughness at ductile-brittle fracture transition region

    Science.gov (United States)

    Tani, T.; Nagumo, M.

    1995-02-01

    The fracture process that determines the Charpy energy at the ductile-brittle transition region was investigated by means of the instrumented Charpy test and fractographic analysis with a low carbon low alloy steel subjected to different control-rolling conditions. The decomposition of a Charpy energy into the energies dissipated in the course of the notch-tip blunting, stable crack growth, and brittle crack propagation is unique irrespective of the testing temperatures and specimen series. Toughness level can be divided into four regions according to the pre-dominating fracture process. The temperature dependence of toughness and effects of the an-isotropy of a specimen originates in the brittle fracture initiation stage rather than the resistance against the notch-tip blunting or stable crack growth. From fractographic examination referring to the stress analyses, it is discussed that the brittle fracture initiation is controlled by the local deformation microstructures in the plastic zone together with the stress field ahead of the notch or the stable crack front.

  16. Impact toughness improvement of high strength aluminium alloy by intrinsic and extrinsic fracture mechanisms via hot roll bonding

    OpenAIRE

    Cepeda-Jiménez, C.M.; García-Infanta, J.M.; Pozuelo, M.; Ruano, Oscar Antonio; Carreño, Fernando

    2009-01-01

    A multilayer aluminium laminate comprising ten layers of Al-Zn-Mg-Cu alloy (82 vol.%) and nine layers of pure aluminium (18 vol.%) has been processed by hot rolling. The rolled laminate was characterized by electron backscattering diffraction, Charpy impact and shear tests. The multilayer laminate showed an outstanding Charpy impact toughness, being eighteen times higher than that for the as-received Al-Zn-Mg-Cu alloy. Damage tolerance improvement was due to the high volume fra...

  17. Impact toughness of tungsten films deposited on martensite stainless steel

    Institute of Scientific and Technical Information of China (English)

    HUANG Ning-kang; YANG Bin; WANG De-zhi

    2005-01-01

    Tungsten films were deposited on stainless steel Charpy specimens by magnetron sputtering followed by electron beam heat treatment. Charpy impact tests and scanning electron microscopy were used to investigate the ductile-brittle transition behavior of the specimens. With decreasing test temperature the fracture mode was transformed from ductile to brittle for both kinds of specimens with and without W films. The data of the crack initiation energy, crack propagation energy, impact absorbing energy, fracture time and deflection as well as the fracture morphologies at test temperature of -70 ℃ show that W films can improve the impact toughness of stainless steel.

  18. Method for Estimating Percent Shear Fracture Appearance of Charpy-V Specimen of Nuclear Pressure Vessel Steel%核压力容器钢冲击断口剪切面积百分比的估算方法

    Institute of Scientific and Technical Information of China (English)

    伍晓勇; 冯明全; 崔永海

    2001-01-01

    Percent shear fracture appearance is an important factor to evaluate neutron irradiation embrittlement of nuclear pressure vessel steel.But it is difficult to measure the irregular surface directly,especially for post-irradiation speciments.Depending on Charpy-V instrumented impact tests,characteristic load values can be determined according to load-deflection curve which completely represents the impact failure processes,and percent shear fracture appearance can be estimated using different formula.The estimating method is more effective to calculate irradiation-induced changes in transition temperature,which already successfully applied to the irradiation surveillance test of reactor pressure vessel steel of Daya-bay nuclear power station.%在核压力容器钢的中子辐照脆化评价中,断口剪切面积百分比是一个重要的参数。但此参数不易直接测量,对于辐照后的放射性试样其测量更加困难。本文采用 Charpy-V示波冲击试验,并根据计算机采集得到的完整记录冲击过程的载荷 -位移曲线,即可确定相应的载荷特征值,同时估算出断口剪切面积百分比。该估算方法用于计算核压力容器钢因中子辐照引起的脆性转变温度的变化值,其计算结果较为准确且计算方法也简便,现已成功地应用于大亚湾核电站压力容器的辐照监督试验。

  19. Effect of neutron irradiation on fracture toughness of metal matrix composites

    Science.gov (United States)

    Sato, Shinji; Hamada, Kenichi; Kohyama, Akira

    1992-09-01

    Based on the recent improvement in mechanical properties of unidirectionally reinforced metal matrix composites (MMCs), SiC/Al and C/Al, impact property change due to neutron irradiation has been investigated. This paper details effects of neutron irradiation on fracture toughness of the MMCs. Materials used were formed sheets of SiC/Al and C/Al. Miniaturized Charpy V-notched specimens were tested by an instrumented Charpy impact tester. Neutron irradiation was performed in JMTR(LWR) at Oarai. The Charpy value was increased with increasing test temperature and with neutron irradiation. SiC/Al was rather more neutron fluence insensitive than C/Al and the insensitivity was correlated to differences in interfacial structure between the two systems.

  20. 碰撞试验

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Drop impact test - mechanics & physics of failure; Drop-impact simulation and experimental verification for spindle fixation of video and audio module;Ductile-brittle transition evaluation of Japanese sword and weld metals using miniaturized impact specimens;Dynamic behavior of high polymers with focus on a macrolon;Dynamic J{sub}R curves of 308 stainless steel weld from instrumented impact test of unprecracked Charpy V-notch specimens;Dynamic mechanical analysis and toughening mechanisms of polycarbonate and 4,4'-dihydorxydiphenyl copolycarbonate;……

  1. Determinación de la tenacidad a la fractura de muestras de Acero 45 fundido, empleando las correlaciones entre el KIC y la energía de impacto medida en el ensayo de Charpy. // Determination of the fracture tenacity of cast Steel grade 45 samples, using th

    Directory of Open Access Journals (Sweden)

    F. Ramos Morales

    2005-05-01

    Full Text Available En el presente trabajo se determinan los valores de tenacidad a la fractura (KIC de muestras de Acero 45 fundido,empleando las correlaciones entre la tenacidad a la fractura y la energía de impacto (CVN obtenida del ensayo de Charpy.Se hace una discusión sobre las correlaciones que más se ajustan en la región de transición y en upper shelf. Se comparanlos valores obtenidos de estas correlaciones a valores de tenacidad a la fractura establecidos en la literatura.Palabras claves: Fractura, energía de impacto, acero fundido.______________________________________________________________________________Abstract.In this paper, the values of fracture toughness (KIC are determined on specimens of cast steel grade 45, using thecorrelations among the fracture toughness (KIC and the impact energy (CVN obtained from a Charpy test. A discussion ismade on the correlations that are better adjusted in the transition region and in upper shelf region. The obtained values arecompared from these correlations to values of fracture toughness (KIC settled down in the literature.Key words. Fracture, impact energy, cast steel.

  2. Instrumented Charpy : analysis of the instrumentation and the effect of different metallurgical conditions of an ultra-high strength steel on the dynamic fracture toughness

    OpenAIRE

    2009-01-01

    Resumo: O ensaio Charpy clássico, utilizado desde o início do século XX, permite determinar a energia global de fratura, propriedade mecânica conhecida como tenacidade. Esta energia tem caráter qualitativo e na aplicação no projeto estrutural, reduz-se a comparações entre as curvas de transição dúctil-frágil dos materiais. Com o surgimento da instrumentação do ensaio Charpy clássico é possível determinar a propriedade mecânica, tenacidade à fratura dinâmica, KId, muito utilizada na Mecânica d...

  3. 46 CFR 54.05-20 - Impact test properties for service of 0 °F and below.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Impact test properties for service of 0 °F and below... ENGINEERING PRESSURE VESSELS Toughness Tests § 54.05-20 Impact test properties for service of 0 °F and below. (a) Test energy. The impact energies of each set of transverse Charpy specimens may not be less...

  4. Irradiation programme MANITU: Results of pre-examinations and Charpy tests with unirradiated materials; Bestrahlungsprogramm MANITU. Ergebnisse der Voruntersuchungen und der Kerbschlagbiegeversuche mit den unbestrahlten Werkstoffen

    Energy Technology Data Exchange (ETDEWEB)

    Rieth, M.; Dafferner, B.; Ries, H.; Romer, O.

    1995-04-01

    The irradiation project MANITU was planned in the frame of the European Long-term Fusion Materials Development Programme. The results of MANITU will have a lasting influence on the future actions within the materials development programme. The problem of the irradiation induced embrittlement of possible martensitic alloy candidates is still unsolved. But after the evaluation of sub-size Charpy tests with the unirradiated refrence specimens of MANITU a first tendency is recognizable. The Charpy properties of the newly developed low activation 7-10% Cr-WVTa alloys are clearly better compared with the modified commerical 10-11% Cr-NiMoVNb steels. In the present report the pre-examinations are documented and the Charpy test results with unirradiated reference specimens are analysed and assessed. (orig.) [Deutsch] Das Bestrahlungsprojekt MANITU wurde im Rahmen des europaeischen Langzeitprogramms fuer Materialentwicklung fuer die Kernfusion geplant. Die daraus gewonnenen Ergebnisse werden das weitere Vorgehen bei der Materialentwicklung entscheidend beeinflussen. Das Problem der bestrahlungsinduzierten Versproedung bei den in Frage kommenden martensitischen Werkstoffen ist nach wie vor ungeloest. Eine erste Tendenz zeichnet sich nach der Auswertung der Kerbschlagbiegeversuche an den unbestrahlten miniaturisierten Referenzproben des MANITU-Programms ab. Die neu entwickelten niedrig aktivierbaren 7-10% Cr-WVTa-Legierungen weisen gegenueber den modifizierten kommerziellen 10-11% Cr-NiMoVNb-Staehlen deutlich bessere Kerbschlageigenschaften auf. Im vorliegenden Bericht werden die Voruntersuchungen dokumentiert und die Ergebnisse aus den Kerbschlagbiegeversuchen der unbestrahlten Referenzproben analysiert und bewertet. (orig.)

  5. Impact energy analysis of HSLA specimens after simulated welding thermal cycle

    Directory of Open Access Journals (Sweden)

    Samarždić, I.

    2008-04-01

    Full Text Available This paper presents impact energy results of specimens made from high strength fine grained steel TStE 420 after thermal cycle simulation. These results are obtained by examining Charpy specimens. Metallographic analysis is performed, hardness is measured and total impact energy is divided into ductile and brittle components.

  6. 真空热处理

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    [篇名 ] Relations between fracture toughness, hardness and microstructure of vacuum heat-treated high-speed steel,[ 篇名 ] Flexible furnace concepts for vacuum heat treatment using high-pressure gas quenching,[ 篇名 ] Effect of boron micro-alloying on microstructure and mechanical properties of fine-grained CM247LC superalloy,[ 篇名] PROPERTIES OF POLYCRYSTALS SINTERED AT HIGH PRESSURES FROM DIAMOND NANOPOWDERS PRODUCED BY DETONATION AND STATIC SYNTHESES,[ 篇名 ] The Effects of Steel Quality, Vacuum Heat Treatment Quench Rate and Charpy V-Notch Impact Test Temperature on the Impact Toughness and Microstructure of Premium Quality H-13 Tool Steel。

  7. Fracture Toughness Evaluation of Kori-1 RPV Beltline Weld for a Long-Term Operation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bong-Sang; Kim, Min-Chul; Ahn, Sang-Bok; Kim, Byung-Chul; Hong, Jun-Hwa [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2007-07-01

    Irradiation embrittlement of RPV (reactor pressure vessel) material is the most important aging issue for a long-term operation of nuclear power plants. KORI unit 1, which is the first PWR in Korea, is approaching its initial licensing life of 30 years. In order to operate the reactor for another 10 years and more, it should be demonstrated that the irradiation embrittlement of the reactor will be adequately managed by ensuring that the fracture toughness properties have a certain level of the safety margin. The current regulation requires Charpy V-notch impact data through conventional surveillance tests. It is based on the assumption that Charpy impact test results are well correlated with the fracture toughness properties of many engineering steels. However, Charpy V-notch impact data may not be adequate to estimate the fracture toughness of certain materials, such as Linde 80 welds. During the last decade, a tremendous number of fracture toughness data on many RPV steels have been produced in accordance with the new standard test method, the so-called master curve method. ASTM E1921 represents a revolutionary advance in characterizing fracture toughness of RPV steels, since it permits establishing the ductile to brittle transition portion of the fracture toughness curve with direct measurements on a relatively small number of relatively small specimens, such as pre-cracked Charpy specimens. Actual fracture toughness data from many different RPV steels revealed that the Charpy test estimations are generally conservative with the exception of a few cases. Recent regulation codes in USA permit the master curve fracture toughness methodology in evaluating an irradiation embrittlement of commercial nuclear reactor vessels.

  8. Effect of Grain Boundary Character Distribution on the Impact Toughness of 410NiMo Weld Metal

    DEFF Research Database (Denmark)

    Divya, M.; Das, Chitta Ranjan; Chowdhury, Sandip Ghosh;

    2016-01-01

    Grain boundary character distributions in 410NiMo weld metal were studied in the as-welded, first-stage, and second-stage postweld heat treatment (PWHT) conditions, and these were correlated with the Charpy-V impact toughness values of the material. The high impact toughness values in the weld me...

  9. Impact energy analysis of quenched and tempered fine grain structural steel specimens after weld thermal cycle simulation

    Directory of Open Access Journals (Sweden)

    M. Dunđer

    2014-10-01

    Full Text Available The paper presents impact energy results of thermal cycle simulated specimens of quenched and tempered fine grain structural steel S960QL. These results are obtained by examining notched Charpy specimens. Upon performed metallographic analysis and measured hardness, total impact energy is separated into ductile and brittle components.

  10. Impact toughness and fracture toughness of austempered ductile iron

    OpenAIRE

    Liu, Jingcheng; Guoxiong SUN

    2004-01-01

    The impact toughness and fracture toughness ofaustermpered ductile iron (ADI) are described. The notched and un-notched charpy impact toughness of ADI at room temperature are somewhat lower than that of steel castings or forged steel pieces, however, they are approximately three times higher than that of mormal pearlitic ductile iron. The impact toughness of ADI decreases with decreasing temperature; but at -40 ℃ it still maintains about 70% of the value at room temperature. The properties of...

  11. Notch sensitivity of hydrogenated oxygen-strengthened titanium

    Science.gov (United States)

    Wasz, M. L.; Ko, C. C.; Brotzen, F. R.; Mclellan, R. B.

    1990-01-01

    While earlier studies have shown that the tensile properties and fracture test intensity factors of oxygen-strengthened Ti remain nearly unaffected by the presence of about 70 ppm (weight) hydrogen, the Charpy V-notch test-determined impact properties of oxygen-bearing Ti are strongly affected by the presence of hydrogen. The present study establishes that, concurrently with the strengthening effect of oxygen, there is a substantial lowering of ductility. The presence of hydrogen has virtually no effect on the notch strength of Ti alloys of either low or high oxygen content, where hydrogen contents lie in the 25-80 range.

  12. Grain refinement of high strength steels to improve cryogenic toughness

    Science.gov (United States)

    Rush, H. F.

    1985-01-01

    Grain-refining techniques using multistep heat treatments to reduce the grain size of five commercial high-strength steels were investigated. The goal of this investigation was to improve the low-temperature toughness as measured by Charpy V-notch impact test without a significant loss in tensile strength. The grain size of four of five alloys investigated was successfully reduced up to 1/10 of original size or smaller with increases in Charpy impact energy of 50 to 180 percent at -320 F. Tensile properties were reduced from 0 to 25 percent for the various alloys tested. An unexpected but highly beneficial side effect from grain refining was improved machinability.

  13. Characterisation of the fracture properties in the ductile to brittle transition region of the weld material of a reactor pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Scibetta, M. [SCK-CEN, Boeretang 200, 2400 Mol (Belgium); Ferreno, D., E-mail: ferrenod@unican.es [University of Cantabria, ETS Ingenieros de Caminos, Av/Los Castros s/n, 39005 Santander (Spain); Gorrochategui, I. [Centro Tecnologico de Componentes (CTC), Parque Cientifico y Tecnologico de Cantabria, Isabel Torres No 1, 39011 Santander (Spain); Nuclenor, SA, C/Hernan Cortes 26, 39003 Santander (Spain); Lacalle, R. [University of Cantabria, ETS Ingenieros de Caminos, Av/Los Castros s/n, 39005 Santander (Spain); Walle, E. van [SCK-CEN, Boeretang 200, 2400 Mol (Belgium); Martin, J. [Nuclenor, SA, C/Hernan Cortes 26, 39003 Santander (Spain); Gutierrez-Solana, F. [University of Cantabria, ETS Ingenieros de Caminos, Av/Los Castros s/n, 39005 Santander (Spain)

    2011-04-15

    This work presents the results of the fracture characterisation of the weld material of a nuclear vessel, currently in service, in the ductile to brittle transition region. The tests consisted of Charpy impact and tensile tests, performed in the framework of the surveillance programme of the plant. Moreover, in the context of this research, K{sub Jc} fracture toughness tests on pre-cracked Charpy V notch specimens (evaluated according to the Master Curve methodology) together with some mini-tensile tests, were performed; non-irradiated and several irradiated material conditions were characterised. The analysis of the experimental results revealed some inconsistencies concerning the material embrittlement as measured through Charpy and K{sub Jc} fracture tests: in order to obtain an adequate understanding of the results, an extended experimental scope well beyond the regulatory framework was developed, including Charpy tests and K{sub Jc} fracture tests, both performed on reconstituted specimens. Moreover, Charpy specimens irradiated in the high flux BR2 material test reactor were tested with the same purpose. With this extensive experimental programme, a coherent and comprehensive description of the irradiation behaviour of the weld material in the transition region was achieved. Furthermore it revealed better material properties in comparison with the initial expectations based on the information obtained in the framework of the surveillance programme.

  14. Measurement of the dynamic fracture toughness with notched PMMA specimen under impact loading

    OpenAIRE

    2009-01-01

    International audience; In the present study three-point-bend impact experiments were conducted using an instrumented Charpy pendulum with a laser displacement measurement to better understand the correlation between impact velocity and the dynamic effects observed on the load-time curves. The experiments were performed at impact velocities ranging from 1 to 4 m/s. The aim of this work is to measure the dynamic fracture toughness at high impact velocities where the classical method is limited...

  15. Definition of the minimum longitude of insert in the rebuilding of Charpy test tubes for surveillance and life extension of vessels in Mexico; Definicion de la longitud minima de inserto en la reconstitucion de probetas Charpy para vigilancia y extension de vida de vasijas en Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Romero C, J.; Hernandez C, R.; Rocamontes A, M., E-mail: jesus.romero@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2011-11-15

    In the National Institute of Nuclear Research (Mexico) a welding system for the rebuilding of Charpy test tubes has been developed, automated, qualified and used for the surveillance of the mechanical properties (mainly embrittlement) of the vessel. This system uses the halves of the rehearsed Charpy test tubes of the surveillance capsules extracted of the reactors, to obtain, of a rehearsed test tube, two reconstituted test tubes. This rebuilding process is used so much in the surveillance program like in the potential extension of the operation license of the vessel. To the halves of Charpy test tubes that have been removed the deformed part by machine are called -insert- and in a very general way the rebuilding consists in weld with the welding process -Stud Welding- two metallic implants in the ends of the insert, to obtain a reconstituted test tube. The main characteristic of this welding are the achieved small dimensions, so much of the areas welded as of the areas affected by the heat. The applicable normative settles down that the minim longitude of the insert for the welding process by Stud Welding it should be of 18 mm, however according to the same normative this longitude can diminish if is demonstrated analytic or experimentally that the central volume of 1 cm{sup 3} in the insert is not affected. In this work the measurement of the temperature profiles to different distances of the welding interface is presented, defining an equation for the maximum temperatures reached in function of the distance, on the other hand the real longitude affected in the test tube by means of metallography is determined and this way the minimum longitude of the insert for this developed rebuilding system was determined. (Author)

  16. Grain size and temperature influence on the toughness of a CuAlBe shape memory alloy

    Energy Technology Data Exchange (ETDEWEB)

    Albuquerque, Victor Hugo C. de, E-mail: victor.albuquerque@fe.up.pt [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Laboratorio de Solidificacao Rapida LSR, Cidade Universitaria, S/N 58059-900 Joao Pessoa, PB (Brazil); Melo, Tadeu Antonio de A, E-mail: tadeu@lsr.ct.ufpb.br [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Laboratorio de Solidificacao Rapida LSR, Cidade Universitaria, S/N 58059-900 Joao Pessoa, PB (Brazil); Gomes, Rodinei M., E-mail: gomes@lsr.ct.ufpb.br [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Laboratorio de Solidificacao Rapida LSR, Cidade Universitaria, S/N 58059-900 Joao Pessoa, PB (Brazil); Lima, Severino Jackson G. de, E-mail: jackson@lsr.ct.ufpb.br [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Laboratorio de Solidificacao Rapida LSR, Cidade Universitaria, S/N 58059-900 Joao Pessoa, PB (Brazil); Tavares, Joao Manuel R.S., E-mail: tavares@fe.up.pt [Faculdade de Engenharia da Universidade do Porto (FEUP), Departamento de Engenharia Mecanica (DEMec)/Instituto de Engenharia Mecanica e Gestao Industrial INEGI, Rua Dr. Roberto Frias, S/N 4200-465 Porto (Portugal)

    2010-11-25

    Research highlights: {yields} This work evaluated the capacity of a CuAlBe alloy to absorb energy until rupture. {yields} The V-notch Charpy test was adopted at -150, -100, -50, 0, 50, 100 and 150 deg. C. {yields} Charpy tests were complemented by DSC, DSC with optical microscope and by SEM. {yields} First work to analyze the toughness of a CuAlBe alloy based on the Charpy test. {yields} The results are of relevant value to enhance the understanding of the CuAlBe alloy. - Abstract: This work is a study of the influence of grain size and temperature on the toughness of CuAlBe shape memory alloys with (CuAlBeNbNi) and without NbNi (CuAlBe) grain refiner elements. The toughness analysis was based on the V-notch Charpy impact test under temperatures of -150, -100, -50, 0, 50, 100 and 150 deg. C. A statistical analysis of the results led to the conclusion that the toughness of both alloys was influenced by temperature and grain size. The CuAlBeNbNi alloy absorbed higher impact energy than the CuAlBe alloy showing that the refining elements improved the toughness of the alloy. To confirm and complement these findings, the fracture surfaces were evaluated by stereomicroscopy. Smooth homogeneous surfaces and rough heterogonous surfaces were detected for the CuAlBeNbNi and CuAlBe alloys, respectively. Predominately brittle zones were confirmed by scanning electron microscopy in both alloys. Furthermore, to determine the phase transformation temperatures and the associated microstructures, the alloys were assessed by conventional differential scanning calorimetry (DSC) and DSC with optical microscopy.

  17. Evaluation of ageing-induced embrittlement in an austenitic stainless steel by instrumented impact testing

    Science.gov (United States)

    Samuel, K. G.; Sreenivasan, P. R.; Ray, S. K.; Rodriguez, P.

    1987-09-01

    Fracture properties of a thermally aged Type 316 stainless steel have been investigated at room temperature by an instrumented impact test. The impact energy is found to depend on the heat treatment conditions. Several alternative estimates for toughness are evaluated and compared with the conventional Charpy impact energy, C v, to assess the degree of embrittlement. Sensitivity of these parameters to monitor the ageing-induced embrittlement in comparison with C v is discussed.

  18. Test Technique Development on the Irradiated Reconstituted PCVN Specimen in Hot Cell

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Sangbok; Oh, Wanho; Choo, Yongsun; Kim, Minchul; Lee, Bongsang [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2006-07-01

    The degradation of fracture toughness is the important factor to restrict the life of nuclear pressure vessel in PWR reactors. A pressure vessel is operated in conformity with the fracture analysis based on ASME codes to ensure safety margins from the unstable fracture. A fracture analysis is performed based on the result from the Charpy impact tests in PWR reactor, but it has the questions to be exact solutions because the test results give indirect and excessively conservative values. Therefore the research to find an exact toughness parameter is undergoing to use the pre-cracked Charpy v-notch (PCVN). As results the master curve method is proposed in ASTM E1921 to be supposed an appropriate tool to evaluate the fracture toughness for the irradiated, or the operated pressure vessel materials. The surveillance test program to evaluate toughness degradation on existing commercial PWR reactor is performed through the impact test on Charpy specimens. It gives the lack of the specimen to evaluate the safety in toughness for on-going operation beyond design life. To overcome the shortage of specimen, the test method to use a reconstituted PCVN specimen fabricated from the broken half of Charpy specimen is proposed and adopted in foreign reactors. In this paper techniques developed for the reconstituted specimen from the domestic commercial PWR reactor in hot cell are described.

  19. Impact properties of the aircraft cast aluminium alloy Al-7Si0.6Mg (A357

    Directory of Open Access Journals (Sweden)

    Alexopoulos N.D.

    2010-06-01

    Full Text Available The impact mechanical properties of the widely used in the aeronautics A357 cast aluminum alloy were investigated by exploiting experiments on an instrumented Charpy impact testing machine. The evaluated impact properties for 25 different artificial aging heat treatment conditions were analyzed and discussed in conjunction with the respective tensile properties. Correlations are proposed to establish useful relationships between impact resistance and tensile strain energy density properties. The established correlations, which are well supported by the performed experiments, can be used to estimate the tensile ductility and toughness of the A357 cast aluminum alloy from the Charpy impact test. Performed fractographic analyses were supporting the physically arbitrary correlation between tensile strain energy density and impact resistance.

  20. Impact properties of the aircraft cast aluminium alloy Al-7Si0.6Mg (A357)

    Science.gov (United States)

    Alexopoulos, N. D.

    2010-06-01

    The impact mechanical properties of the widely used in the aeronautics A357 cast aluminum alloy were investigated by exploiting experiments on an instrumented Charpy impact testing machine. The evaluated impact properties for 25 different artificial aging heat treatment conditions were analyzed and discussed in conjunction with the respective tensile properties. Correlations are proposed to establish useful relationships between impact resistance and tensile strain energy density properties. The established correlations, which are well supported by the performed experiments, can be used to estimate the tensile ductility and toughness of the A357 cast aluminum alloy from the Charpy impact test. Performed fractographic analyses were supporting the physically arbitrary correlation between tensile strain energy density and impact resistance.

  1. A Repeated Impact Method and Instrument to Evaluate the Impact Fatigue Property of Drillpipe

    Science.gov (United States)

    Lin, Yuanhua; Li, Qiang; Sun, Yongxing; Zhu, Hongjun; Zhou, Ying; Xie, Juan; Shi, Taihe

    2013-04-01

    It is well known that drillpipe failures are a pendent problem in drilling engineering. Most of drillpipe failures are low amplitude-repeated impact fatigue failures. The traditional method is using Charpy impact test to describe the fracture property of drillpipe, but it cannot veritably characterize the impact fatigue property of drillpipe under low amplitude-repeated impact. Based on the Charpy impact and other methods, a repeated impact method and instrument have been proposed to simulate the low amplitude-repeated impact of downhole conditions for drillpipe. Then, a series of tests have been performed using this instrument. Test results demonstrate the drillpipe upset transition area nonhomogeneity is more severe than drillpipe body, which is the key factor that leads to washout and fracture frequently of it. As the one time impact energy increases, the repeated impact times decrease exponentially, therefore, the rotational speed has a great effect on the fatigue life of drillpipe, and it is vital to select a suitable rotational speed for drilling jobs. In addition, based on SEM fractographs we found that the fracture surface of repeated impact is similar to the fatigue fracture, and there are many low cycle fatigue characteristic features on fracture surface that reveal very good agreement with the features of drillpipe fatigue failures in the field.

  2. Impact Resistance of Structural Ceramics. Part 1. Instrumented Drop- Weight Tests

    Science.gov (United States)

    1976-05-01

    instrumented Charpy test and the instrumented DWT. The Impact Fracture Energy of a ceramic is determined by its dynamic strength. At room temperature...AFML-TR-76-56 ~I’S PART I 0 IMPACT RESISTANCE OF STRUCTURAL CERAMICS PART I: INSTRUMENTED DROP-WEIGHT TESTS PROCESSING AND HIGH TEMPERATURE MATERIALS...BLAG..OTP ,fIJMED .. TABLE OF CONTENTS SECTION PAGE I INTRODUCTION 1 II DROP-WEIGHT TEST (DWT) 3 III EXPERIMENTAL PROCEDURES FOR THE INSTRUMENTED DWT AT

  3. Applicability of the Modified Ritchie-Knott-Rice Failure Criterion to Examine the Feasibility of Miniaturized Charpy Type SE(B Specimens

    Directory of Open Access Journals (Sweden)

    Toshiyuki Meshii

    2016-01-01

    Full Text Available This paper examined whether the modified Ritchie-Knott-Rice (RKR failure criterion can be applied to examine the feasibility of miniaturized Charpy type SE(B specimens of thickness-to-width ratio B/W=1. The modified RKR failure criterion considered in this paper is the (4δt,σ22c criterion which predicts the onset of cleavage fracture when the midplane crack-opening stress measured at a distance equal to four times the crack-tip opening displacement, denoted as σ22d, exceeds a critical stress σ22c. Specimens with B values of 25, 10, 3, and 2 mm (denoted as 25t, 10t, 3t, and 2t specimens, resp. manufactured with 0.55% carbon steel were tested at 20°C. The results showed that the modified RKR criterion could appropriately predict the occurrence of cleavage fracture accompanied by negligibly small stable crack extension (denoted as KJc fracture naturally for the 25t and 10t specimens. The modified RKR criterion could also predict that KJc fracture does not occur for the 2t specimen. The σ22c obtained from specimens for the 25t and 10t specimens exhibited only a small difference, indicating that the Jc obtained from the 10t specimens can be used to predict the Jc that will be obtained with the 25t specimens.

  4. The impact resistance of SiC and other mechanical properties of SiC and Si3N4

    Science.gov (United States)

    Bradt, R. C.

    1984-01-01

    Studies focused on the impact and mechanical behavior of SiC and Si3N4 at high temperatures are summarized. Instrumented Charpy impact testing is analyzed by a compliance method and related to strength; slow crack growth is related to processing, and creep is discussed. The transient nature of flaw populations during oxidation under load is emphasized for both SiC and Si3N4.

  5. A mechanical property and stress corrosion evaluation of VIM-ESR-VAR work strengthened and direct double aged Inconel 718 bar material

    Science.gov (United States)

    Montano, J. W.

    1986-01-01

    Presented are the mechanical properties and the stress corrosion resistance of triple melted vacuum induction melted (VIM), electro-slag remelted (ESR), and vacuum arc remelted (VAR), solution treated, work strengthened and direct double aged Inconel 718 alloy bars 4.00 in. (10.16) and 5.75 in. (14.60 cm) diameter. Tensile, charpy v-notched impact, and compact tension specimens were tested at ambient temperature in both the longitudinal and transverse directions. Longitudinal tensile and yield strengths in excess of 220 ksi (1516.85 MPa) and 200 ksi (1378.00 MPa) respectively, were realized at ambient temperature. Additional charpy impact and compact tension tests were performed at -100 F (-73 C). Longitudinal charpy impact strength equalled or exceeded 12.0 ft-lbs (16.3 Joules) at ambient and at -100 F(-73 C) while longitudinal compact (LC) tension fracture toughness strength remained above 79 ksi (86.80 MPa) at ambient and at -100 F(-73 C) temperatures. No failures occurred in the longitudinal or transverse tensile specimens stressed to 75 and 100 percent of their respective yield strengths and exposed to a salt fog environment for 180 days. Tensile tests performed after the stress corrosion test indicated no mechanical property degradation.

  6. Influence of Mo addition on the tempered properties of 13Cr martensitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Byong Ho; Ahn, Yong Sik [Pukyong National Univ., Busan (Korea, Republic of)

    1998-11-01

    In order to investigate the effect of Mo addition on the mechanical properties of 13Cr-0.2C martensitic stainless steel, tensile test and Charpy V-notch test were performed after tempering at the temperature range of 200{approx}700 .deg. C following austenitizing at 1100 .deg. C. The yield strength and hardness of the steel were increased with the increase of Mo content at all tempering conditions, because Mo causes retardation of precipitation and coarsening of carbides and solid solution strengthening of matrix. Except 500 .deg. C of tempering temperature, the Charpy impact energy was significantly increased with Mo content and showed the highest value at 1.5 wt% addition. The increase of impact energy of the steel containing Mo is thought to be caused by {delta}-ferrite formed in the tempered martensitic matrix. At 500 .deg. C tempering, Charpy impact energy was decreased drastically due to temper embrittlement and it was not possible to prevent it even though Mo was added up to 1.5 wt%.

  7. Fracture-Toughness Analysis in Transition-Temperature Region of Three American Petroleum Institute X70 and X80 Pipeline Steels

    Science.gov (United States)

    Shin, Sang Yong; Woo, Kuk Je; Hwang, Byoungchul; Kim, Sangho; Lee, Sunghak

    2009-04-01

    The fracture toughness in the transition-temperature region of three American Petroleum Institute (API) X70 and X80 pipeline steels was analyzed in accordance with the American Society for Testing and Materials (ASTM) E1921-05 standard test method. The elastic-plastic cleavage fracture toughness ( K Jc ) was determined by three-point bend tests, using precracked Charpy V-notch (PCVN) specimens; the measured K Jc values were then interpreted by the three-parameter Weibull distribution. The fracture-toughness test results indicated that the master curve and the 98 pct confidence curves explained the variation in the measured fracture toughness well. The reference temperatures obtained from the fracture-toughness test and index temperatures obtained from the Charpy impact test were lowest in the X70 steel rolled in the two-phase region, because this steel had smaller effective grains and the lowest volume fraction of hard phases. In this steel, few hard phases led to a higher resistance to cleavage crack initiation, and the smaller effective grain size led to a higher possibility of crack arrest, thereby resulting in the best overall fracture properties. Measured reference temperatures were then comparatively analyzed with the index temperatures obtained from the Charpy impact test, and the effects of microstructures on these temperatures were discussed.

  8. Impact

    NARCIS (Netherlands)

    Lohse, Detlef; Bergmann, Raymond; Mikkelsen, Rene; Zeilstra, Christiaan; Meer, van der Devaraj; Versluis, Michel

    2004-01-01

    A lot of information on impacts of solid bodies on planets has been extracted from remote observations of impact craters on planetary surfaces; experiments however with large enough impact energies as compared to the energy stored in the ground are difficult. We approach this problem by downscaled e

  9. Factors affecting miniature Izod impact strength of tungsten-fiber-metal-matrix

    Science.gov (United States)

    Winsa, E. A.; Petrasek, D. W.

    1973-01-01

    The miniature Izod and Charpy impact strengths of copper, copper-nickel, and nickel-base superalloy uniaxially reinforced with continuous tungsten fibers were studied. In most cases, impact strength was increased by increasing fiber or matrix toughness, decreasing fibermatrix reaction, increasing test temperature, hot working, or heat treating. Notch sensitivity was reduced by increasing fiber content or matrix toughness. An equation relating impact strength to fiber and matrix properties and fiber content was developed. Program results imply that tungsten alloy-fiber/superalloy matrix composites can be made with adequate impact resistance for turbine blade or vane applications.

  10. Microstructure and Failure Analysis of Flash Butt Welded HSLA 590CL Steel Joints in Wheel Rims

    Science.gov (United States)

    Lu, Ping; Xu, Zhixin; Shu, Yang; Ma, Feng

    2016-11-01

    The aim of the present investigation was to evaluate the microstructures, mechanical properties and failure behavior of flash butt welded high strength low alloy 590CL steel joints. Acicular ferrite, Widmanstatten ferrite and granular bainite were observed in the weld. The micro-hardness values of the welded joints varied between 250 HV and 310 HV. The tensile strength of the welded joints met the strength standard of the wheel steel. The Charpy V-notch impact absorbing energy of the welded joints was higher than the base metal, and the impact fracture of the welded joints was composed of shearing and equiaxed dimples. The fracture mode of the wheel rim in the flaring and expanding process was brittle fracture and ductile fracture, respectively. A limited deviation was found in the terminal of the crack for the wheel in the flaring process. A transition from the weld to the Heat Affected Zone was observed for the wheel in the expanding process.

  11. Toughness testing and high-temperature oxidation evaluations of advanced alloys for core internals

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Lizhen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pint, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chen, Xiang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-16

    Alloy X-750 was procured from Carpenter Technology and Bodycote in this year. An appropriate TMT was developed on Alloy 439 to obtain materials with refined grain size for property screening tests. Charpy V-notch impact tests were completed for the three ferritic steels Grade 92, Alloy 439, and 14YWT. Fracture toughness tests at elevated temperatures were completed for 14YWT. The tests will be completed for the other alloys in next fiscal year. Steam oxidation tests of the three ferritic steels, 316L, and Zr–2.5Nb have been completed. The steam tests of the Ni-based superalloys and the other austenitic stainless steels will be continued and finished in next fiscal year. Performance ranking in terms of steam oxidation resistance and impact/fracture toughness of the alloys will be deduced.

  12. Toughness testing and high-temperature oxidation evaluations of advanced alloys for core internals

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Lizhen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pint, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chen, Xiang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-16

    In summary, Alloy X-750 was procured from Carpenter Technology and Bodycote in this year. An appropriate TMT was developed on Alloy 439 to obtain materials with refined grain size for property screening tests. Charpy V-notch impact tests were completed for the three ferritic steels Grade 92, Alloy 439, and 14YWT. Fracture toughness tests at elevated temperatures were completed for 14YWT. The tests will be completed for the other alloys in next fiscal year. Steam oxidation tests of the three ferritic steels, 316L, and Zr–2.5Nb have been completed. The steam tests of the Ni-based superalloys and the other austenitic stainless steels will be continued and finished in next fiscal year. Performance ranking in terms of steam oxidation resistance and impact/fracture toughness of the alloys will be deduced.

  13. The Effect of Constant and Pulsed Current Gas Tungsten Arc Welding on Joint Properties of 2205 Duplex Stainless Steel to 316L Austenitic Stainless Steel

    Science.gov (United States)

    Neissi, R.; Shamanian, M.; Hajihashemi, M.

    2016-05-01

    In this study, dissimilar 316L austenitic stainless steel/2205 duplex stainless steel (DSS) joints were fabricated by constant and pulsed current gas tungsten arc welding process using ER2209 DSS as a filler metal. Microstructures and joint properties were characterized using optical and electron scanning microscopy, tensile, Charpy V-notch impact and micro-hardness tests, and cyclic polarization measurements. Microstructural observations confirmed the presence of chromium nitride and delta ferrite in the heat-affected zone of DSS and 316L, respectively. In addition, there was some deviation in the austenite/ferrite ratio of the surface welding pass in comparison to the root welding pass. Besides having lower pitting potential, welded joints produced by constant current gas tungsten arc welding process, consisted of some brittle sigma phase precipitates, which resulted in some impact energy reduction. The tensile tests showed high tensile strength for the weld joints in which all the specimens were broken in 316L base metal.

  14. Standard Guide for In-Service Annealing of Light-Water Moderated Nuclear Reactor Vessels

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This guide covers the general procedures to be considered for conducting an in-service thermal anneal of a light-water moderated nuclear reactor vessel and demonstrating the effectiveness of the procedure. The purpose of this in-service annealing (heat treatment) is to improve the mechanical properties, especially fracture toughness, of the reactor vessel materials previously degraded by neutron embrittlement. The improvement in mechanical properties generally is assessed using Charpy V-notch impact test results, or alternatively, fracture toughness test results or inferred toughness property changes from tensile, hardness, indentation, or other miniature specimen testing (1). 1.2 This guide is designed to accommodate the variable response of reactor-vessel materials in post-irradiation annealing at various temperatures and different time periods. Certain inherent limiting factors must be considered in developing an annealing procedure. These factors include system-design limitations; physical constrain...

  15. Verification of the effect of surface preparation on Hot Isostatic Pressing diffusion bonding joints of CLAM steel

    Science.gov (United States)

    Zhao, Yanyun; Li, Chunjing; Huang, Bo; Liu, Shaojun; Huang, Qunying

    2014-12-01

    Hot Isostatic Pressing (HIP) diffusion bonding with CLAM steel is the primary candidate fabrication technique for the first wall (FW) of DFLL-TBM. Surface state is one of the key factors for the joints quality. The effect of surface state prepared with grinder and miller on HIP diffusion bonding joints of CLAM steel was investigated. HIP diffusion bonding was performed at 140 MPa and 1373 K within 3 h. The mechanical properties of the joints were investigated with instrumented Charpy V-notch impact tests and the microstructures of the joints were analyzed with scanning electron microscopy (SEM). The results showed that the milled samples with fine surface roughness were more suitable for CLAM steel HIP diffusion bonding.

  16. Verification of the effect of surface preparation on Hot Isostatic Pressing diffusion bonding joints of CLAM steel

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yanyun [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Li, Chunjing, E-mail: chunjing.li@fds.org.cn [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Bo; Liu, Shaojun [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Qunying [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

    2014-12-15

    Hot Isostatic Pressing (HIP) diffusion bonding with CLAM steel is the primary candidate fabrication technique for the first wall (FW) of DFLL-TBM. Surface state is one of the key factors for the joints quality. The effect of surface state prepared with grinder and miller on HIP diffusion bonding joints of CLAM steel was investigated. HIP diffusion bonding was performed at 140 MPa and 1373 K within 3 h. The mechanical properties of the joints were investigated with instrumented Charpy V-notch impact tests and the microstructures of the joints were analyzed with scanning electron microscopy (SEM). The results showed that the milled samples with fine surface roughness were more suitable for CLAM steel HIP diffusion bonding.

  17. Impacts

    NARCIS (Netherlands)

    Hellmuth, M.; Kabat, P.

    2003-01-01

    Even without the impacts of climate change, water managers face prodigious challenges in meeting sustainable development goals. Growing populations need affordable food, water and energy. Industrial development demands a growing share of water resources and contaminates those same resources with its

  18. Comparison of Instrumented Impact Standard and Testing Technology between Multiaxial Impact and Charpy Impact%仪器化多轴冲击和简支梁冲击标准与试验技术的比较

    Institute of Scientific and Technical Information of China (English)

    戴婷

    2015-01-01

    分析比较了仪器化多轴冲击标准ISO 6603-2和简支梁冲击标准ISO 179-2的异同,着重讨论了这些标准在测试技术上的不同要求,探讨了试验机性能对试验结果的影响,并提出了对试验机测控系统软硬件设计的技术要求.提出实验人员要了解不同类型冲击试验标准的差异,在实际测试过程中根据具体测试目的选择合适的试验方法;测试数据的精确度、曲线的质量保障和测试标准有关,还和试验机的性能有关,要求实验人员熟知试验机的核心技术参数,同时了解所选测试标准对试验机的要求,选择满足测试需求的试验机.

  19. The Effects of Ionized Gas Exposure on the Toughness and Fatigue Properties of Aluminum Alloys and Composites.

    Science.gov (United States)

    Zaat, Stephen Vincent

    The effects of an oxygen ionized gas from simulated space exposure on the toughness and fatigue properties of several aerospace aluminum alloys and aluminum composites have been analyzed. The test matrix consisted of four aluminum systems: the 6000 and 1100 series and two 8090 aluminum-lithium alloys. The test specimens were prepared as Charpy V-notched impact and disk-shaped compact fracture toughness specimens. A small specimen size is used for the compact tension specimens to facilitate exposure in a Radio Frequency (RF) Plasma Prep II unit. Radio frequency plasma, sometimes referred to as the "electrodeless plasma", is used in disassociative ionization of molecular oxygen to simulate high fluence, relatively low energy, low earth orbit (LEO) space atomic oxygen. The plasma reacts with the aluminum alloy systems and forms a thin scale of alumina a few microns thick. Monolayer sensitive Variable Angle Spectroscopic Ellipsometry (VASE) is used to determine the growth characteristics and effect on optical constants, the reflective index, n and absorption coefficient, k. Atomic Force Microscopy (AFM) was also employed to determine the effect of short exposure to the oxygen plasma environment. AFM indicates that sharp spikes of oxygen rich material are produced above the aluminum specimen surface resulting in stress concentrations with gradual roughing of the surface. After 10 years of simulated exposure, the increased roughness results in a 34% increase in the fatigue crack growth, da/dN, for the 6000 series; the crack growth rate of the aluminum-lithium material was increased about 28%. The results of instrumented Charpy V-notched impact specimens indicated that exposure reduced the energy for fracture initiation by 29%. Plane strain fracture toughness effects could not be established because the influence of oxygen was concentrated at the surface of the specimens.

  20. IMPACTS !

    CERN Multimedia

    2008-01-01

    (Photo courtesy of Don Davis / NASA)The University of Geneva (UNIGE) and the Ecole Polytechnique Fédérale of Lausanne (EPFL) are organising the 4th series of public lectures on astronomy, on the theme of "Impacts". The schedule is as follows: Il y a 100 ans : une explosion dans la Tunguska – Dr. Frédéric COURBIN, EPFL Les impacts sur Terre – Prof. Didier Queloz, UNIGE La fin des dinosaures – Dr. Stéphane Paltani, UNIGE Wednesday 7 May 2008, from 7.00 p.m. to 9.00 p.m. Auditoire CO1, EPFL, Ecublens Thursday 08 May 2008, from 7.00 p.m. to 9.00 p.m. Auditoire Rouiller, Uni-Dufour, Genève All 3 lectures will be givent each evening! Admission free Information: 022 379 22 00

  1. Subtask 12F4: Effects of neutron irradiation on the impact properties and fracture behavior of vanadium-base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.M.; Loomis, B.A.; Smith, D.L. [Argonne National Lab., IL (United States)

    1995-03-01

    Up-to-date results on the effects of neutron irradiation on the impact properties and fracture behavior of V, V-Ti, V-Cr-Ti and V-Ti-Si alloys are presented in this paper, with an emphasis on the behavior of the U.S. reference alloys V-4Cr-4Ti containing 500-1000 wppm Si. Database on impact energy and cluctile-brittle transition temperature (DBTT) has been established from Charpy impact tests of one-third-size specimens irradiated at 420{degrees}C-600{degrees}C up to {approx}50 dpa in lithium environment in fast fission reactors. To supplement the Charpy impact tests fracture behavior was also characterized by quantitative SEM fractography on miniature tensile and disk specimens that were irradiated to similar conditions and fractured at -196{degrees}C to 200{degrees}C by multiple bending. For similar irradiation conditions irradiation-induced increase in DBTT was influenced most significantly by Cr content, indicating that irradiation-induced clustering of Cr atoms takes place in high-Cr (Cr {ge} 7 wt.%) alloys. When combined contents of Cr and Ti were {le}10 wt.%, effects of neutron irradiation on impact properties and fracture behavior were negligible. For example, from the Charpy-impact and multiple-bend tests there was no indication of irradiation-induced embrittlement for V-5Ti, V-3Ti-1Si and the U.S. reference alloy V-4Cr-4Ti after irradiation to {approx}34 dpa at 420{degrees}C to 600{degrees}C, and only ductile fracture was observed for temperatures as low as -196{degrees}C. 14 refs., 8 figs., 1 tab.

  2. Evaluation of Crashworthiness for SAE Materials under Ductile to Brittle Transition Temperature (DBTT

    Directory of Open Access Journals (Sweden)

    Amol Bhanage

    2014-10-01

    Full Text Available The concept of crashworthy coaches came into existence after a crash. This demands, avoid vehicle deformation of other/central parts. For this, the behaviour of plastic deformation of the material is necessary to be known. So, these results are required to study the crashworthy behaviour of the structure. In this research, Comparative study has been taken on the automotive materials of SAE 1026, SAE 4140, SAE 5120 and SAE8620. This paper presents the results of fracture toughness, impact energy and stress required for crack propagation from Charpy v-notch impact test and tensile test. The mechanical behaviour of SAE 1026, SAE 4140, SAE 5120 and SAE 8620 are important to describe response during actual loading condition properties used in the crash analysis of the component. The Charpy impact test was conducted at temperature ranging from room temperature 24°C, 0°C, -20°C, - 40°C, -60°C. Specimens oriented in T-L direction are tested. The materials SAE 1026, SAE 4140, SAE 5120 and SAE8620 shown that the ductile to brittle transition temperature, based on 19.5 J, 10.5 J, 113 J, 59.5 J, absorbed energy is about 1.2°C, -3°C, -38°C, -10°C respectively.

  3. Impact tests of the tungsten coated stainless steels prepared by using magnetron sputtering with ion beam mixing or electron beam alloying treatment

    Science.gov (United States)

    Zou, Yu; Zhan, Chang-Yong; Yang, Bin; Wu, Jian-Chun

    2013-05-01

    Tungsten films were deposited on stainless steel (SS) with ion beam mixing (IBM) or electron beam alloying (EBA) treatment. The ductile-brittle transition behaviors of the specimens were investigated by means of instrumented Charpy impact test at a series of temperature, and SEM was used to observe the morphology of the cross section. Impact tests show that different treatment methods with W films do not have much influence on crack initiation, while EBA treatment with W films can more effectively prevent crack propagation, namely improve the impact toughness of SS than using IBM treatment. The reason that caused this difference was discussed.

  4. Impact Resistance of Short Fibre/Particle Reinforced Epoxy

    Science.gov (United States)

    Chang, L.; Zhang, Z.; Breidt, C.

    2004-01-01

    The influence of temperature on the fracture behaviour of epoxy-based composites was studied using an instrumented Charpy impact approach. A series of epoxy reinforced with short carbon fibres (SCF) and additionally filled with various amounts of PTFE and graphite particles was considered in this study. Unnotched specimens were tested at -196°C, 20°C, and 70°C, respectively. It was found that, for specimens with the same matrix content, a proper hybridisation of composites was possible to achieve a better impact performance compared to single-filler/epoxy. For example, 10 vol.%PTFE+10 vol.%SCF/epoxy exhibited a higher impact resistance than that of 20 vol.%SCF/epoxy at all measured temperatures. Failure mechanisms at different temperatures were discussed with SEM fractography.

  5. Impact toughness and fracture toughness of austempered ductile iron

    Directory of Open Access Journals (Sweden)

    Jingcheng LIU

    2004-11-01

    Full Text Available The impact toughness and fracture toughness ofaustermpered ductile iron (ADI are described. The notched and un-notched charpy impact toughness of ADI at room temperature are somewhat lower than that of steel castings or forged steel pieces, however, they are approximately three times higher than that of mormal pearlitic ductile iron. The impact toughness of ADI decreases with decreasing temperature; but at -40 ℃ it still maintains about 70% of the value at room temperature. The properties of fracture toughness are important in safety design and failure analysis. In this study all fracture toughness data of ADI are higher than that of conventional ductile iron, and are equivalent to or better than that of steel castings o forged steel pieces with the tensile strength equivalent to ADI.

  6. Instrumented Impact Testing: Influence of Machine Variables and Specimen Position

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E.; McCowan, C. N.; Santoyo, R. A.

    2008-09-15

    An investigation has been conducted on the influence of impact machine variables and specimen positioning on characteristic forces and absorbed energies from instrumented Charpy tests. Brittle and ductile fracture behavior has been investigated by testing NIST reference samples of low, high and super-high energy levels. Test machine variables included tightness of foundation, anvil and striker bolts, and the position of the center of percussion with respect to the center of strike. For specimen positioning, we tested samples which had been moved away or sideways with respect to the anvils. In order to assess the influence of the various factors, we compared mean values in the reference (unaltered) and altered conditions; for machine variables, t-test analyses were also performed in order to evaluate the statistical significance of the observed differences. Our results indicate that the only circumstance which resulted in variations larger than 5 percent for both brittle and ductile specimens is when the sample is not in contact with the anvils. These findings should be taken into account in future revisions of instrumented Charpy test standards.

  7. MICROSTRUCTURE AND IMPACT FRACTURE BEHAVIOUR OF HAZ OF F460 HEAVY SHIP PLATE WITH HIGH STRENGTH AND TOUGHNESS%F460高强韧厚船板焊接热影响区的组织和冲击断裂行为

    Institute of Scientific and Technical Information of China (English)

    刘东升; 程丙贵; 罗咪

    2011-01-01

    Thermal cycles of the heat-affected zone (HAZ) of an advanced F460 steel plate used as offshore structure and ship-building in the future were simulated by employing a Gleeble 3800 ther-momechanical simulator. The microstructures of the HAZ formed at different heat input energies (E) were characterized by means of OM, SEM, EBSD and TEM, and mechanical properties were measured. When E is equal to 15 kJ/cm, the microstructures consist of mainly lath-like martensite (LM) with high density dislocations and large misorientations, between the laths exist fine martensite/austenite (M/A) constituents. When E is equal to 30 kJ/cm, lath-like bainite (LB) is formed. The lath grains and M/A constituents will coarsen and the amount of high angle (≥15°) boundaries will decrease with the increase of E to 50 kJ/cm. When E is in a range of 100-300 kJ/cm, the microstructures consist of granular bainite (GB)+upper bainite (UB)+quasi-polygonal ferrite (QPF). The hardness of the HAZ (HV), the maximum Charpy V notch (CVN) impact load (Pm), the brittle fracture arrested load (Pa), the crack propagation rate, and the entire displacement (d0) of the CVN impact course decrease with the increase of E. The size of cleavage facets increases with the increase of E, which can be used to explain the effective grain size of the HAZ increases with the increase of E, as a result, the hardness decreases and low temperature toughness deteriorates as E increases. The upper limit of the simulated heat input E for the F460 steel is 30 kJ/cm which makes the toughness of the HAZ equivalent to that of the mother plate at -60 ℃.%使用Gleeble-3800热模拟试验机模拟单道次焊接条件下大厚度(50 mm)F460钢板热影响区(HAZ)热循环过程,通过OM,SEM,EBSD和TEM研究了HAZ的显微组织随热输入(E)的演化规律.测试了不同E下HAZ的室温硬度(HV),在-40和-60℃下进行了Charpy冲击示波实验(CVN).当E=15 kJ/cm时,显微组织为高位错密度板条马氏体(LM),板条

  8. Low temperature impact strength of heavy section ductile iron castings: effects of microstructure and chemical composition

    Directory of Open Access Journals (Sweden)

    C. Labrecque

    2011-02-01

    Full Text Available A foundry research project has been recently initiated at RTIT in order to better understand the fabrication of as-cast heavy section DI parts meeting high impact energy requirements at low temperatures. The experimental castings have the following dimensions 180 mm x 180 mm x 190 mm. The achieved as-cast Charpy impact strengths were as follows: 17 J (RT, 16 J (-20°C and 11 J (-40°C. The foundry process, the chemical composition and the microstructure of this experimental casting are compared to the ones of various examples in order to show the detrimental effects of residual elements, microshrinkage and microcarbide on the impact properties. Finally, quality index empirical models (based on casting chemical compositions are used to analyse the impact tests results. This paper illustrates that an adequate nodule count can contribute to reducing the detrimental effects of the residual elements and microsegregation.

  9. Mechanical characterization based in the impact test of the cadmium-zinc and cadmium-zinc-copper alloys; Caracterizacion mecanica basada en la prueba de impacto de las aleaciones cadmio-zinc y cadmio-zinc-cobre

    Energy Technology Data Exchange (ETDEWEB)

    Casolco, S.R.; Torres V, G. [Instituto de Investigacion en Materiales, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-360, 04510 Mexico D.F. (Mexico)

    1999-11-01

    The present work is a study carried out in the Institute for Materials Research of the UNAM, of the alloys cadmium-zinc and cadmium-zinc-copper with the fundamental objective of knowing their behavior to the impact that which will allow to establish structural applications of these alloys. This work consists mainly on impact tests of the type Charpy at different temperatures in a range of - 150 Centigrade to 250 Centigrade and to study their fracture morphologies with the help of a scanning electron microscope to recognize the tendency of the material toward the fracture of the fragile type and to determine the ductile-fragile transition. (Author)

  10. Soil Erosion and Surface Water Quality Impacts of Natural Gas Development in East Texas, USA

    Directory of Open Access Journals (Sweden)

    Matthew McBroom

    2012-11-01

    Full Text Available Due to greater demands for hydrocarbons and improvements in drilling technology, development of oil and natural gas in some regions of the United States has increased dramatically. A 1.4 ha natural gas well pad was constructed in an intermittent stream channel at the Alto Experimental Watersheds in East Texas, USA (F1, while another 1.1 ha well pad was offset about 15 m from a nearby intermittent stream (F2. V-notch weirs were constructed downstream of these well pads and stream sedimentation and water quality was measured. For the 2009 water year, about 11.76 cm, or almost 222% more runoff resulted from F1 than F2. Sediment yield was significantly greater at F1, with 13,972 kg ha−1 yr−1 versus 714 kg ha−1yr−1 at F2 on a per unit area disturbance basis for the 2009 water year. These losses were greater than was observed following forest clearcutting with best management practices (111–224 kg ha−1. Significantly greater nitrogen and phosphorus losses were measured at F1 than F2. While oil and gas development can degrade surface water quality, appropriate conservation practices like retaining streamside buffers can mitigate these impacts.

  11. The effect of strain rate on the impact strength of the high-Mn steel

    Directory of Open Access Journals (Sweden)

    A. Śmiglewicz

    2015-10-01

    Full Text Available In the paper, results of impact bending tests of a high-manganese steel of Fe – 30 wt.%, Mn – 9 wt.%, Al – 0,65 wt.%, C grade are presented. The tests were carried out using a flywheel machine, suitable for dynamic stretching and impact bending tests in the range of linear velocity of the forcing element from 5 ÷ 40 m/s. The obtained test results were compared with the results of impact resistance of the studied steel determined using Charpy machine. Structural investigations were carried out using scanning transmission electron microscopy. Surfaces of fractures formed in the break point during bending tests were analyzed, and they indicate a presence of mixed transcrystalline fractures with a predominance of plastic fractures.

  12. Effect of waveform graph of instrumented Charpy impact test on fracture mode with QT400-18L at low temperature%含镍QT400-18L低温断裂方式的分析

    Institute of Scientific and Technical Information of China (English)

    路焱

    2010-01-01

    示波冲击试验可以记录试样在断裂过程中载荷与冲击吸收功的完整信息,反映试样在承受冲击过程时载荷与时间的变化规律.使用示波冲击试验机测试了含镍QT400-18L试样低温环境下的冲击韧性,记录不同含镍量的球铁试样-40℃低温下的裂纹形成功与裂纹扩展功以及冲击载荷与时间的波形图.研究结果表明,不同含镍量QT400-18L试样发生不同形式的断裂,其中,镍的质量分数为0.70%的试样发生弹性变形的过程最长,弹性变形所需能量的消耗最大,断裂方式为韧性、脆性的混合型断裂,因此其低温冲击韧性最大,αkv可达到20.87 J/cm2.

  13. RPSW/A摆锤示波冲击试验机测试系统改造%Modification to the Testing System of RPSW/A Pendulum Instrumented Charpy Impact Testing Machine

    Institute of Scientific and Technical Information of China (English)

    周海; 邵建龙; 方淑芳

    2006-01-01

    介绍了RPSW/A摆锤示波冲击试验机的基本组成、工作原理及存在的问题,提出了Windows平台下通过多功能PCI数据采集卡实现高速数据采集的设想.在此基础上用VB编写了数据采集及处理软件,使该试验机恢复正常,并解决了原机测试系统存在的故障率高、试验数据不易保存、操作烦琐等不足.

  14. Characteristics of the IAEA correlation monitor material for surveillance programmes

    Science.gov (United States)

    Wallin, Kim; Valo, Matti; Rintamaa, Rauno; Toerroenen, Kari; Ahlstrand, Ralf

    1989-08-01

    Correlation monitor material developed to meet the needs of the IAEA (International Atomic Energy Association) coordinated research program for optimizing reactor pressure vessel surveillance programs and their analysis is described. The material is intended to serve as a reference within the IAEA for future vessel surveillance programs throughout the world. The results of an extensive evaluation of the material in the as-received condition are presented. The mechanical properties measured at different temperatures include Charpy V notch and instrumented precracked Charpy data. Elastic-plastic fracture toughness is studied. Specimen size and geometry are varied in the tests. Correlations between different fracture properties are evaluated and discussed.

  15. Fundamental study of crack initiation and propagation. Annual progress report, March 1976--March 1977

    Energy Technology Data Exchange (ETDEWEB)

    Norris, D.M. Jr. (ed.)

    1977-06-01

    Ductile fracture in nuclear pressure vessel steel was characterized using a computer model of material damage. The model predicts crack initiation and growth and contains constants that are set by computer simulation of the following fracture tests: the simple tension test, the circumferentially notched round tension test, the blunt-notched compact tension test, and the Charpy V-notch test. The simulations provide the stress and strain states of these tests at fracture. The major goal of our characterization program is to determine the correlation between Charpy toughness and fracture toughness.

  16. Weldability investigation of fine-grained S1100QL steel

    Directory of Open Access Journals (Sweden)

    I. Samardžić

    2016-07-01

    Full Text Available This paper presents the results of weldability investigation on welded joints made of fine - grained high-strength S1100QL steel. The investigations are performed on two welded plates by HV 10 hardness measuring and by Charpy V notch testing at different test temperatures. Mechanical properties of welded joints are overviewed, along with welded parameters, all of which enable obtaining of high-quality welded joints.

  17. Gas Metal Arc Welding Process Modeling and Prediction of Weld Microstructure in MIL A46100 Armor-Grade Martensitic Steel

    Science.gov (United States)

    2013-06-01

    Ref 9] Within this technique, the progress of the assumed/predicted phase transformations is related to dimensional changes to the test sample; (b...uniform elongation, eUTS = 10-13%; Charpy V-notch absorbed energy, UCharpy-V = 25-30 J; specific heat, CV = 440-520 J/kg ÆK; thermal conductivity, k = 35...Valentich, Tube Type Dilatometers: Applications From Cryogenic to Elevated Temperatures, Instrument Society of America, Research Triangle Park, NC

  18. Influence of strain localization on deformation mechanisms and fracture of 12Cr1MoV steel with various notch shape under impact loading

    Science.gov (United States)

    Panin, S. V.; Vlasov, I. V.; Maruschak, P. O.; Moiseenko, D. D.; Berto, F.; Vinogradov, A.; Bischak, R. T.; Maksimov, P. V.

    2016-11-01

    The energy of 12Cr1MoV steel specimen fracture with V-, U- and I-shaped notches under impact loading was measured and analyzed. The results were described using common energy-based approach to ductile-brittle fracture. Within the stage-wise approach of physical mesomechanics of materials, the rate of increase/decrease of load at the stage of initiation and propagation of a macroscopic defect was evaluated, providing a good correlation with the work of fracture. The excitable cellular automata technique was applied to simulate the deformational behavior of the specimens with different shape of notches. It was demonstrated that in the case of the blunted notch, the maximum impact toughness is facilitated by a more uniform distribution of the load along the notch, which hinders brittle fracture at lower testing temperature. For the specimen with the sharp I-notch, the bands of localized shear are oriented normally to the loading axis, inhibiting macrolocalization of strain and crack propagation. For this reason, the impact toughness of the specimen with the I-notch appeared to be higher than that of the V-notched one.

  19. Subtask 12D2: Baseline impact properties of vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.M.; Loomis, B.A.; Smith, D.L. [Argonne National Lab., IL (United States)

    1995-03-01

    The objective of this work is to determine the baseline impact properties of vanadium-base alloys as a function of compositional variables. Up-to-date results on impact properties of unirradiated V, V-Ti, V-Cr-Ti and V-Ti-Si alloys are presented and reviewed in this paper, with an emphasis on the most promising class of alloys, i.e., V-(4-5)Cr-(3-5)Ti containing 400-1000 wppm Si. Database on impact energy and ductile-brittle transition temperature (DBTT) has been established from Charpy impact tests on small laboratory as well as production-scale heats. DBTT is influenced most significantly by Cr contents and, to a lesser extent, by Ti contents of the alloys. When combined contents of Cr and Ti were {le}10 wt.%, V-Cr-Ti alloys exhibit excellent impact properties, i.e., DBTT<-200{degrees}C and upper shelf energies of {approx}120-140 J/cm{sup 2}. Impact properties of the production-scale heat of the U.S. reference alloy V-4Cr- 4Ti were as good as those of the laboratory-scale heats. Optimal impact properties of the reference alloy were obtained after annealing the as-rolled products at 1000{degrees}C-1050{degrees}C for 1-2 h in high-quality vacuum. 17 refs., 6 figs., 2 tabs.

  20. Interface Effects on the Quasi-Static and Impact Toughness of Discontinuously Reinforced Aluminum Laminates

    Science.gov (United States)

    Osman, Todd M.; Hassan, Hala A.; Lewandowski, John J.

    2008-08-01

    Trilayer laminates consisting of two layers of aluminum alloy 7093 surrounding one layer of 7093/SiC/15 p were produced via two roll-bonding techniques as well as by adhesive bonding. The effects of systematic changes in interface characteristics ( i.e., weak bond via roll bonding with a thin ductile interlayer material, stronger bond via roll bonding without a thin ductile interlayer, and strongest bond via adhesive bonding with a semibrittle material) on the subsequent laminate toughness was studied. The fracture resistance of the laminates and the constituent materials was examined via instrumented Charpy notched impact testing in the crack-arrester orientation as well as by fracture-toughness testing of bend bars tested in the crack-divider and the crack-arrester orientations. The notched impact resistance of the trilayer crack-arrester laminates was found to be greater than both monolithic 7093/SiC/15 p and 7093 samples of similar global thickness. The laminated structure promoted crack arrest, deflection, and large-scale deformation of the unreinforced layers, producing R-curve behavior. The tendency for interface delamination was predicted and confirmed based on recent mechanics-based analyses. The trilayer laminate structures tested in the crack-divider orientation exhibited a greater R-curve than either of the 7093/SiC/15 p or 7093 samples tested at similar global thickness. Both types of roll-bonded laminates ( i.e., stronger interface and weak interface containing a thin metal interlayer) exhibited a greater enhancement in Charpy impact toughness and mode I fracture toughness than did the adhesively bonded ( i.e., semibrittle interface) laminates. These relative improvements in toughness were rationalized by estimating the contributions to energy absorption by the delamination and crack bridging in these systems and by the effects of the interface type on these processes. These results are generally relevant to the performance of these materials under

  1. Fundamental study of crack initiation and propagation. [Computer model of ductile fracture

    Energy Technology Data Exchange (ETDEWEB)

    Norris, D.M. Jr.; Reaugh, J.E.; Moran, B.; Quinones, D.F.; Wilkins, M.L.

    1977-12-21

    Objective is to determine the fracture toughness of A533B-1 steel by computer modeling Charpy V-notch tests. A computer model of ductile fracture was developed that predicts fracture initiation. The model contains a set of material-dependent parameters obtained by computer simulations of small specimen tests. The computer calculations give detailed stress and strain histories up to the time of fracture, which are used to determine the model parameter values. The calibrated fracture model, that correctly predicts fracture initiation (and initiation energy) in the Charpy specimen, may then be used to simulate tests of accepted fracture-toughness specimens and hence obtain fracture toughness. The model parameters were calibrated to predict fracture in four different test specimens: two different notched-tension specimens, a simple tension specimen, and a precracked compact-tension specimen. The model was then used in a computer simulation of the Charpy V-notch specimen to initiate and advance a flat fracture. Results were compared with interrupted Charpy tests. Calibration of the model for two additional heat treatments of A533B-1 steel is in progress.

  2. Tensile and impact properties of General Atomics 832864 heat of V-4Cr-4Ti alloy

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, H.; Nowicki, L.J.; Gazda, J.; Billone, M.C.; Smith, D.L. [Argonne National Lab., IL (United States); Johnson, W.R.; Trester, P. [General Atomics, San Diego, CA (United States)

    1998-09-01

    A 1300-kg heat of V-4Cr-4Ti alloy was procured by General Atomics (GA) for the DIII-D radiative divertor program. To determine the mechanical properties of this alloy, tensile and Charpy tests were conducted on specimens prepared from pieces of 4.8-mm-thick as-rolled plates, a major product form for the DIII-D application. The tensile tests were conducted at three temperatures, 26, 280 and 380 C, the last two being the anticipated peak temperatures during DIII-D boronization and postvent bake-out, respectively. Results from these tests show that the tensile and impact properties of the 832864 heat are comparable to those of the other smaller V-(4-5)Cr-(4-5)Ti alloy heats previously developed by the US Fusion Materials Program and that scale-up of vanadium alloy production can be successfully achieved as long as reasonable process control is implemented.

  3. Evaluation of effect of hydrogen on toughness of Zircaloy-2 by instrumented drop weight impact testing

    Science.gov (United States)

    Viswanathan, U. K.; Singh, R. N.; Basak, C. B.; Anantharaman, S.; Sahoo, K. C.

    2006-05-01

    Hydride-assisted degradation in fracture toughness of Zircaloy-2 was evaluated by carrying out instrumented drop-weight tests on curved Charpy specimens fabricated from virgin pressure tube. Samples were charged to 60 ppm and 225 ppm hydrogen. Ductile-to-brittle-transition behaviour was exhibited by as-received and hydrided samples. The onset of ductile-to-brittle-transition was at about 130 °C for hydrided samples, irrespective of their hydrogen content. Dynamic fracture toughness ( KID) was estimated based on linear elastic fracture mechanics (LEFM) approach. For fractures occurring after general yielding, the fracture toughness was derived based on equivalent energy criterion. Results are supplemented with fractography. This simple procedure of impact testing appears to be promising for monitoring service-induced degradation in fracture toughness of pressure tubes.

  4. Influence of helium on impact properties of reduced-activation ferritic/martensitic Cr-steels

    Science.gov (United States)

    Lindau, R.; Möslang, A.; Preininger, D.; Rieth, M.; Röhrig, H. D.

    Instrumented Charpy impact tests of the reduced activation type 8Cr2WVTa steel F82H have been performed after homogeneous implantation of 300 appm helium at 250°C. The results are compared with investigations on mixed spectrum neutron irradiated (HFR Petten) specimens. After neutron irradiation at 250°C to the same low damage dose of 0.2 dpa, the ductile-brittle transition temperature shift (ΔDBTT) amounts to 18°C, whereas a much higher ΔDBTT of 42°C has been measured after helium implantation. These results are compared with other neutron irradiated ferritic/martensitic steels having different boron levels and thus different helium contents. A model is proposed which describes the dynamic brittle fracture of martensitic/ferritic steels by a stress-induced propagation of micro-cracks, taking into account radiation induced hardening as well as helium bubble formation.

  5. V-Notched Bar Creep Life Prediction: GH3536 Ni-Based Superalloy Under Multiaxial Stress State

    Science.gov (United States)

    Zhang, D. X.; Wang, J. P.; Wen, Z. X.; Liu, D. S.; Yue, Z. F.

    2016-07-01

    In this study, creep experiments on smooth and circumferential V-type notched round bars were conducted in GH3536 Ni-based superalloy at 750 °C to identify notch strengthening effect in notched specimens. FE analysis was carried out, coupled with continuum damage mechanics (CDM), to analyze stress distribution and damage evolution under multiaxial stress state. The creep deformation of smooth specimens and the rupture life of both smooth and notched specimens showed good agreement between experimental results and FE analysis predictions; the creep rupture life for the notched specimen was successfully predicted via the "skeletal point" concept. Both creep damage analysis and the observed fracture morphology suggest that creep rupture started first at the root in the V-type notched specimens, and shifted to the region close to the notch root when the notch was relatively shallow compared to U-type notched specimens.

  6. Effect of tempering temperature on the microstructure and mechanical properties of a reactor pressure vessel steel

    Science.gov (United States)

    Li, C. W.; Han, L. Z.; Luo, X. M.; Liu, Q. D.; Gu, J. F.

    2016-08-01

    The microstructure and mechanical properties of reactor pressure vessel (RPV) steel were investigated after tempering at different temperatures ranging from 580 to 700 °C for 5 h. With increasing tempering temperature, the impact toughness, which is qualified by Charpy V-notch total absorbed energy, initially increases from 142 to 252 J, and then decreases to 47 J, with a maximum value at 650 °C, while the ultimate tensile strength varies in exactly the opposite direction. Comparing the microstructure and fracture surfaces of different specimens, the variations in toughness and strength with the tempering temperature were generally attributed to the softening of the bainitic ferrite, the agminated Fe3C carbides that resulted from decomposition of martensite/austenite (M/A) constituents, the precipitation of Mo2C carbides, and the newly formed M/A constituents at the grain boundaries. Finally, the correlation between the impact toughness and the volume fraction of the M/A constituents was established, and the fracture mechanisms for the different tempering conditions are explained.

  7. Impact strength of denture polymethyl methacrylate reinforced with continuous glass fibers or metal wire.

    Science.gov (United States)

    Vallittu, P K; Vojtkova, H; Lassila, V P

    1995-12-01

    The impact strength of heat-cured acrylic resin test specimens that had been reinforced in various ways was compared in this study. Ten rectangular test specimens were fabricated for each test group. The strengtheners included 1.0-mm-diameter steel wire and continuous E-glass fibers. Both notched and unnotched test specimens were tested in a Charpy-type impact test. In a further analysis the concentration of glass fibers in the test specimens was determined and plotted against the impact strength of the test specimens. The results showed that, compared with the unreinforced specimens, both types of reinforcement increased the impact strength of the test specimens considerably (p < 0.001). There was no clear difference between the mean impact strength value of the test specimens reinforced with metal wire and that of the specimens reinforced with glass fiber. The correlation coefficient between the fiber concentration of the test specimens and their impact strength was 0.818 (p < 0.005). Specimens with fiber concentrations greater than 25 wt% yielded to the higher impact strength more readily than those with metal wire reinforcement did.

  8. Processing and impact properties of steel based laminated composites; Procesado y propiedades de impacto de materiales compuestos laminados de base hierro

    Energy Technology Data Exchange (ETDEWEB)

    Carreno, F.; Pozuelo, M.; Chao, J.; Ruano, O. A.

    2001-07-01

    A seven layers steel based laminated composite (four ultra-high carbon steel, UHCS, layers and three mild steel, MS layers) has been processed by rolling bonding and its microstructure and impact properties have been studied. Suitable parameters of temperature and thickness reduction were selected to obtain a finer microstructure relative to the original materials components. This finer microstructure induces improved mechanical properties. Charpy impact tests values in both crack arrester and crack divider orientations improve the values of the UHCS constituent materials. Furthermore, the crack arrester orientation value exceed that of the MS material. The delamination, which is controlled by interface bonding, plays a key role defecting the crack, absorbing energy and imposing the nucleation of new cracks in the next materials layers. (Author) 10 refs.

  9. Required grades of hull steel plates in consideration of fracture toughness; Hakai jinsei wo koryoshita sentaiyo koban shiyo kubun ni kansuru ichikosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Yajima, H.; Yamamoto, M.; Ogaki, Y. [Hiroshima University, Hiroshima (Japan). Faculty of Engineering

    1997-10-01

    This paper discusses the required grades of hull steel plates based on the steel ship rule of Nippon Kaiji Kyokai (NK). The minimum value of the allowable crack length in NK rule (critical safety crack length at 0degC just before brittle unstable crack causing fatal fracture) was estimated. In the case where the estimated crack tip exists in a matrix, the crack length was a minimum of 200-210mm, while nearly 60mm in a fusion line at high-heat-input welded joint. The allowable crack lengths estimated from a specified value in the NK rule were fairly different. The allowable crack length at 0degC was also estimated from the minimum value in V-notch Charpy impact test. The private proposal on the required grades of hull steel plates in consideration of fracture toughness was discussed. Thirty-five percent of crack lengths found in real ships is 100mm or less, however, cracks of 250-400mm long are frequently found suggesting the allowable crack length of 400mm. The required grade integrally considering required values and design conditions is demanded to secure the reliability of hull strength. 5 refs., 5 figs., 2 tabs.

  10. Application of the Master Curve approach for the irradiation embrittlement evaluation of pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Viehrig, H.W.; Boehmert, J. [Forschungszentrum Rossendorf e.V., Inst. fuer Sicherheitsforschung, Dresden (Germany)

    2003-09-01

    The master curve (MC) approach and the associated reference temperature, T{sub 0}, as defined in the test standard ASTM E1921, is rapidly moving from the research laboratory to application in integrity assessment of components and structures. T{sub 0} is the index temperature for the universal MC, which considers the toughness behaviour of a specific material. ''The Structural Integrity Assessment Procedures for European Industry'' (SINTAP) contain a MC extension for analysing the fracture behaviour of inhomogeneous ferritic steels. This paper presents the application of the MC approach to the T{sub 0} determination of different types of Russian WWER-type reactor pressure vessel (RPV) steels. In addition the SINTAP-MC approach was applied to determine an alternative reference temperature, T{sub R}. The influence of different microstructures and compositions within one type of RPV steel and the effect of irradiation with fast neutrons on T{sub 0} are experimentally evaluated. In general the MC based T{sub 0} is about 72 K below the Charpy V-notch transition temperature related to an impact energy of 48 J. The paper demonstrates the application of MC based T{sub 0} and T{sub R} as an alternative reference temperature for neutron embrittled RPV steels used in the RPV integrity assessment. (orig.)

  11. An Assessment of the Ductile Fracture Behavior of Hot Isostatically Pressed and Forged 304L Stainless Steel

    Science.gov (United States)

    Cooper, A. J.; Smith, R. J.; Sherry, A. H.

    2017-02-01

    Type 300 austenitic stainless steel manufactured by hot isostatic pressing (HIP) has recently been shown to exhibit subtly different fracture behavior from that of equivalent graded forged steel, whereby the oxygen remaining in the component after HIP manifests itself in the austenite matrix as nonmetallic oxide inclusions. These inclusions facilitate fracture by acting as nucleation sites for the initiation, growth, and coalescence of microvoids in the plastically deforming austenite matrix. Here, we perform analyses based on the Rice-Tracey (RT) void growth model, supported by instrumented Charpy and J-integral fracture toughness testing at ambient temperature, to characterize the degree of void growth ahead of both a V-notch and crack in 304L stainless steel. We show that the hot isostatically pressed (HIP'd) 304L steel exhibits a lower critical void growth at the onset of fracture than that observed in forged 304L steel, which ultimately results in HIP'd steel exhibiting lower fracture toughness at initiation and impact toughness. Although the reduction in toughness of HIP'd steel is not detrimental to its use, due to the steel's sufficiently high toughness, the study does indicate that HIP'd and forged 304L steel behave as subtly different materials at a microstructural level with respect to their fracture behavior.

  12. Comparison of ductile-to-brittle transition curve fitting approaches

    Energy Technology Data Exchange (ETDEWEB)

    Cao, L.W. [School of Materials Science and Engineering, Beihang University (BUAA), Beijing 100191 (China)] [Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR (United Kingdom); Wu, S.J., E-mail: wusj@buaa.edu.cn [School of Materials Science and Engineering, Beihang University (BUAA), Beijing 100191 (China); Flewitt, P.E.J. [Interface Analysis Centre, University of Bristol, Bristol BS2 8BS (United Kingdom)] [School of Physics, HH Wills Laboratory, University of Bristol, BS8 1TL (United Kingdom)

    2012-05-15

    Ductile-to-brittle transition (DBT) curve fitting approaches are compared over the transition temperature range for reactor pressure vessel steels with different kinds of data, including Charpy-V notch impact energy data and fracture toughness data. Three DBT curve fitting methods have been frequently used in the past, including the Burr S-Weibull and tanh distributions. In general there is greater scatter associated with test data obtained within the transition region. Therefore these methods give results with different accuracies, especially when fitting to small quantities of data. The comparison shows that the Burr distribution and tanh distribution can almost equally fit well distributed and large data sets extending across the test temperature range to include the upper and lower shelves. The S-Weibull distribution fit is poor for the lower shelf of the DBT curve. Overall for both large and small quantities of measured data the Burr distribution provides the best description. - Highlights: Black-Right-Pointing-Pointer Burr distribution offers a better fit than that of a S-Weibull and tanh fit. Black-Right-Pointing-Pointer Burr and tanh methods show similar fitting ability for a large data set. Black-Right-Pointing-Pointer Burr method can fit sparse data well distributed across the test temperature. Black-Right-Pointing-Pointer S-Weibull method cannot fit the lower shelf well and show poor fitting quality.

  13. Ductile tearing of crack-like defects during hydrostatic testing of pipes

    Energy Technology Data Exchange (ETDEWEB)

    Hippert, E.; Donato, G.V.P.; Teixeira, J.C.G.; Lima de, R.S. [Petrobras, Rio de Janeiro (Brazil)

    2004-07-01

    Although hydrostatic testing is widely used to monitor pipeline integrity, experimental studies have shown that flaw growth can occur during hydrostatic testing procedures. This study investigated the effect of pipeline hydrostatic testing on ductile crack growth of prior crack-like defects. Six segments of 3 m length API X60 steel pipes were tested. Each segment contained an electro-sparking erosion part-wall defects positioned both externally and internally on the base metal. Crack extension for external part-wall defects was monitored using an ultrasonic technique. Pipe resistance curves of applied load versus crack depth were obtained for each crack configuration. Laboratory curves were obtained from fracture mechanics tests pieces and then used to determine the initiation of stable extension of the applied load defects. It was observed that the level of crack tip constraint and triaxiality were similar to those experienced in real structures. It was suggested that single edge notch tensile (SET) specimens may be the most suitable specimens for predicting pipeline toughness behavior. A suitable parameter for estimating hydrostatic testing pressure was derived from values obtained during Charpy V-notch impact testing. It was concluded that future research will focus on the development of SET specimens and testing methods. 12 refs., 4 tabs., 11 figs.

  14. The Mechanical properties and microstructural relationships in iron--manganese--chromium alloys. [14 to 20% Mn, 13 to 18% Cr, Al and Ti additions

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, L.D.

    1977-01-01

    The relationships between microstructure and mechanical properties were studied for a series of Fe--Mn--Cr alloys. A combination of optical and scanning electron microscopy, EDAX analysis, and x-ray diffractometry was used to characterize the microstructures. Tensile testing and Charpy V-notch impact testing were utilized to study the mechanical properties. Triplex structures of gamma (fcc), alpha (bcc), and epsilon (hcp) were obtained in air-cool and quench-and-refrigeration heat treatments. Increasing volume fractions of metastable austenite and epsilon-martensite phases, which transform during testing, were found to have beneficial effects on the toughness and ductility properties, without significant losses in strength properties. A chromium concentration of 13 percent led to a better combination of strength and ductility than a concentration of 18 percent. The mechanical properties and preliminary corrosion results for the air-cooled 18Mn--13Cr and 16Mn--13Cr alloys are comparable to those of AISI 300 series austenitic stainless steels. These alloys show promise, therefore, as base systems for replacement austenitic stainless alloys. In addition, the 18Mn--13Cr air-cooled alloy exhibits excellent cryogenic properties, i.e., a yield strength of 360 MPa (53 ksi), an ultimate strength of 1110 MPa (161 ksi) an elongation of 60 percent, and a reduction in area of 17 percent at -196/sup 0/C. 62 figures, 9 tables.

  15. Results of crack-arrest tests on two irradiated high-copper welds

    Energy Technology Data Exchange (ETDEWEB)

    Iskander, S.K.; Corwin, W.R.; Nanstead, R.K. (Oak Ridge National Lab., TN (USA))

    1990-12-01

    The objective of this study was to determine the effect of neutron irradiation on the shift and shape of the lower-bound curve to crack-arrest data. Two submerged-arc welds with copper contents of 0.23 and 0.31 wt % were commercially fabricated in 220-mm-thick plate. Crack-arrest specimens fabricated from these welds were irradiated at a nominal temperature of 288{degree}C to an average fluence of 1.9 {times} 10{sup 19} neutrons/cm{sup 2} (>1 MeV). Evaluation of the results shows that the neutron-irradiation-induced crack-arrest toughness temperature shift is about the same as the Charpy V-notch impact temperature shift at the 41-J energy level. The shape of the lower-bound curves (for the range of test temperatures covered) did not seem to have been altered by irradiation compared to those of the ASME K{sub Ia} curve. 9 refs., 21 figs., 10 tabs.

  16. Investigations into the microstructure-toughness relation in high frequency induction welded pipes

    Energy Technology Data Exchange (ETDEWEB)

    Gungor, O. E.; Thibaux, P.; Liebeherr, M. [ArcelorMittal Global RnD Ghent, Zelzate, (Belgium); Yan, P.; Bhadeshia, H. K. D. H. [Material Science and Mettalurgy, University of Cambridge, (United Kingdom); Quidord, D. [ArcelorMittal Commercial FCE, Fos-sur-Mer, (France)

    2010-07-01

    High frequency induction is frequently used in the production of longitudinally welded pipes for gas transmission but there is some concern about the lower toughness of the weld metal. The HFI welds require in-line post-weld heat treatment (PWHT) to ensure better weld properties. This study investigated the effect of the high frequency induction (HFI) welding process and in-line post-weld heat treatment on weld properties. Tests were performed on HFI welded X65 pipes with a diameter of 24''. Mechanical properties of the pipes were evaluated using Charpy impact (V-notch) and tensile tests before and after PWHT. The EBSD technique was used to study the microtexture and grain structure of the welds. The results showed that the toughness of the bond line after PWHT was sufficiently high, but it is still lower than that of the base material. The coarse crystallographic grain size at the junction of the welds was found to be one of the main reasons for the low toughness.

  17. Effect of composition and processing on the thermal fatigue and toughness of high performance die steels. Year 1 report

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, J.F.; Wang, Yumin; Schwam, D.

    1996-06-01

    The goal of this project is to extend the lifetime of dies for die casting by 20%. Since the die contributes about 10% to the cost of die cast parts, such an improvement in lifetime would result in annual savings of over $200 Million dollars. This is based on the estimated annual die production of one Billion dollars in the US. The major tasks of this two year project are: (1) Evaluate NEW DIE STEEL COMPOSITIONS that have been developed for demanding applications and compare them to Premium Grade H-13 die steel. (2) Optimize the AUSTENITIZING TREATMENT of the new composition. Assess the effects of fast, medium and slow COOLING RATES DURING HEAT TREATMENT, on the thermal fatigue resistance and toughness of the die steel. (3) Determine the effect of ELECTRO-DISCHARGE MACHINING (EDM) on the thermal fatigue resistance and impact properties of the steel. (4) Select demanding components and conduct IN-PLANT TESTING by using the new steel. Compare the performance of the new steel with identical components made of Premium Grade H-13. The immersion thermal fatigue specimen developed at CWRU is being used to determine resistance to heat checking, and the Charpy V-notch test for evaluating the toughness. The overall result of this project will be identification of the best steel available on the market and the best processing methods for aluminum die casting dies. This is an interim report for year 1 of the project.

  18. Advanced-gas-cooled-nuclear-reactor materials evaluation and development program. Volume 1. Final report, September 23, 1976-September 30, 1982

    Energy Technology Data Exchange (ETDEWEB)

    Kimball, O.F.

    1983-05-15

    Included in this report is a discussion of the materials selected for the screening phase and more intensive screening phase test programs and the systems and components for which they are candidate materials. Thirty-one (31) commercially available alloy and alloy/coating materials and ten (10) experimental alloys were evaluated in the program. The experimental test facilities developed as part of this program are discussed and experimental testing procedures are summarized. The results of the initial screening test programs are presented. This includes creep testing results and metallographic analyses of candidate materials exposed to simulated HTGR helium and air under stress at temperatures of 750/sup 0/, 850/sup 0/, 950/sup 0/, or 1050/sup 0/C (1382/sup 0/, 1562/sup 0/, 1742/sup 0/, or 1922/sup 0/F) for exposure times to 10,000 hours. Metallographic analyses, weight change and carbon analyses results, and post exposure room temperature tensile and Charpy V-notch impact test results are presented for candidate materials exposed unstressed under the conditions stated above.

  19. Further application of the cleavage fracture stress model for estimating the T{sub 0} of highly embrittled ferritic steels

    Energy Technology Data Exchange (ETDEWEB)

    Sreenivasan, P.R.

    2016-02-15

    The semi-empirical cleavage fracture stress model (CFS), based on the microscopic cleavage fracture stress, s{sub f}, for estimating the ASTM E1921 reference temperature (T{sub 0}) of ferritic steels from instrumented impact testing of unprecracked Charpy V-notch specimens is further confirmed by test results for additional steels, including steels highly embrittled by thermal aging or irradiation. In addition to the ferrite-pearlite, bainitic or tempered martensitic steels (which was examined earlier), acicular or polygonal ferrite, precipitation-strengthened or additional simulated heat affected zone steels are also evaluated. The upper limit for the applicability of the present CFS model seems to be T{sub 41J} ∝160 to 170 C or T{sub 0} or T{sub Qcfs} (T{sub 0} estimate from the present CFS model) ∝100 to 120 C. This is not a clear-cut boundary, but indicative of an area of caution where generation and evaluation of further data are required. However, the present work demonstrates the applicability of the present CFS model even to substantially embrittled steels. The earlier doubts expressed about T{sub Qcfs} becoming unduly non-conservative for highly embrittled steels has not been fully substantiated and partly arises from the necessity of modifications in the T{sub 0} evaluation itself at high degrees of embrittlement suggested in the literature.

  20. Influence of Constituent Materials on the Impact Toughness and Fracture Mechanisms of Hot-Roll-Bonded Aluminum Multilayer Laminates

    Science.gov (United States)

    Cepeda-Jiménez, C. M.; Hidalgo, P.; Pozuelo, M.; Ruano, O. A.; Carreño, F.

    2010-01-01

    Two aluminum multilayer laminates have been processed by hot roll bonding following similar processing paths. The first one is constituted by alternated Al 2024 and Al 1050 layers (ALH19) and the second one by alternated Al 7075 and Al 1050 layers (ADH19). The influence of the constituent materials in the multilayer laminates both during the processing at high temperature and during the subsequent mechanical characterization has been analyzed. The mechanical behavior of the as-received materials at the processing conditions has been characterized by hot torsion. Multilayer laminates have been tested at room temperature under impact Charpy tests, three-point bend tests, and shear tests on the interfaces. The relative toughness increase compared to the constituent materials was much higher for the ADH19 laminate based on the high-strength Al 7075 alloy than for the ALH19 laminate. This is attributed to the different fracture mechanism.

  1. Irradiation programme MANITU: results of impact tests with the irradiated materials (2,4 dpa); Bestrahlungsprogramm MANITU. Ergebnisse der Kerbschlagbiegeversuche mit den bis 2,4 dpa bestrahlten Werkstoffen

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, H.C.; Dafferner, B.; Ries, H.; Romer, O.

    2001-05-01

    The irradiation project MANITU was planned and carried out in the frame of the European long-term fusion materials development programme. The problem of the irradiation induced embrittlement of possible martensitic alloy candidates is still unsolved. But after the evaluation of sub-size Charpy tests with the unirradiated reference specimens of MANITU a first tendency was recognizable. The mechanical properties of the newly developed low activation 7-10% Cr-W(Ge)VTa alloys are partly better compared to the modified commercial 10-11% Cr-NiMoVNb steels. After the evaluation of subsize Charpy tests with specimens irradiated up to 0.2 and 0.8 dpa in the first phase of the MANITU programme, better mechanical properties of the 7-10% Cr-W(Ge)VTa alloys were obvious. In the present report the results of instrumented impact tests within the second phase of the MANITU programme (irradiation dose 2.4 dpa, irradiation temperatures 250, 300, 350, 400, and 450 C) are analysed and assessed in comparison to the results of the irradiation up to 0.2 and 0.8 dpa in the first phase of the project. Among the examined alloys (MANET-I/II, K-Heat, OPTIFER-Ia/II, F82H, ORNL 3791) the ORNL steel shows the very best embrittlement behaviour after neutron irradiation. (orig.)

  2. Impact and hardness optimisation of composite materials inspired by the babassu nut (Orbignya speciosa).

    Science.gov (United States)

    Staufenberg, Gerrit; Graupner, Nina; Müssig, Jörg

    2015-08-20

    The babassu nut is the fruit of the babassu palm Orbignya speciosa. The combination of hardness and impact strength is difficult to acquire for artificial materials, making the babassu nut a promising source for biomimetic inspiration. Unnotched Charpy impact tests, Shore D hardness tests and scanning electron microscopy were used for mechanical and microscopical analysis of the pericarp. Four major principles were found for a biomimetic approach: a hard core ((1); endocarp) is embedded in a soft outer layer of high impact strength ((2); epicarp) and is reinforced with fibres of variable fineness (3), some of which are oriented radial to the core (4). Biomimetic fibre-reinforced composites were produced using abstracted mechanisms of the babassu nut based on regenerated cellulose fibres (lyocell, L) with two different fineness values as reinforcement embedded in a polylactide (PLA) core matrix and polypropylene (PP) based outer layers. The biomimetic fibre composite reaches a significantly higher impact strength that is 1.6 times higher than the reference sample produced from a PLA/PP/L-blend. At the same time the hardness is slightly increased compared to PP/L.

  3. Improving Impact Strength Recovery of Fractured and Healed Rice Husks Fibre Reinforced Polypropylene Composites.

    Directory of Open Access Journals (Sweden)

    Odhong, O.V.E

    2016-10-01

    Full Text Available Rice husks fibre reinforced polypropylene composite (rhfrpc is a natural plant fibre reinforced polymer composite having advantages of high strength, light weight and affordability. They are commonly used for light load structural and non structural applications. They are mainly used as particle boards, for fencing post, roofing tiles, for interiors of car and aircrafts among other usages. This material once cracked by impact forces cannot be repaired using traditional repair methods for engineering materials such as metals or other composites that can be repaired by welding or by patch repair methods respectively, thus a method of repair of rice husks fibre reinforced polypropylene composites by refilling the damaged volume by injection of various healing agents has been investigated. The composite coupons were produced by injection moulding, cooled sufficiently and prepared for charpy impact tests. Test results for pristine coupons were a maximum of 48 J/mm2 . The destroyed coupons were then subjected to healing in a fabricated healing fixture. Healing agents such as epoxy resin, ethyl cyanoacrylate, and tannin gum have been investigated for their use as possible healing agents to fill the damaged volume and perform healing action at the fractured surfaces. The impact test results were recorded and compared with those of unhealed pristine coupons. The recovered strengths were a maximum of 60 J/mm2 translating into a 125% impact strength recovery, and this is good enough for the healed composites to be recommended for reuse in their second lives of their respective original functions.

  4. Fracture mechanisms assessment of a multilayer material with high strength and excellent impact toughness based on the aerospace Al 7075 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Cepeda-Jimenez, C. M.; Ruano, O. A.; Carreno, F.

    2012-11-01

    An aluminium multilayer laminate has been processed by hot rolling. It is constituted by 19 alternated layers of high-strength aluminium alloy (Al 7075-T6, 82 % vol) and thinner pure aluminium layers (Al 1050-H24, 18 % vol). The microstructure of the constituent alloys and the composition gradient across the interfaces has been characterized. The multilayer laminate and the as-received aluminium alloys have been tested at room temperature by Vickers microhardness, three-point bend test and impact Charpy test. The outstanding improvement in damage tolerance, which is 18 times higher than that for the as-received Al 7075 alloy, is due to both intrinsic and extrinsic fracture mechanisms operating in the multilayer laminate during mechanical testing. (Author) 19 refs.

  5. Quantitative fractography under light microscopy: A digital image processing approach; Quantitative Fraktographie mittels Lichtmikroskopie: Naeherung durch digitale Bildverarbeitung

    Energy Technology Data Exchange (ETDEWEB)

    Horovistiz, A.L.; Ribeiro, L.M.F.; Campos, K.A.; Jesuino, G.A.; Guimaraes, V.A.; Hein, L.R.O. [UNESP, Guaratingueta, SP (Brazil)

    2003-02-01

    This work is an example of the improvement on quantitative fractography by means of digital image processing and light microscopy. Two techniques are presented to investigate the quantitative fracture behavior of Ti-4Al-4V heat-treated alloy specimens, under Charpy impact testing. The first technique is the Minkowski method for fractal dimension measurement from surface profiles, revealing the multifractal character of Ti-4Al-4V fracture. It was not observed a clear positive correlation of fractal values against Charpy energies for Ti-4Al-4V alloy specimens, due to their ductility, microstructural heterogeneities and the dynamic loading characteristics at region near the V-notch. The second technique provides an entire elevation map of fracture surface by extracting in-focus regions for each picture from a stack of images acquired at successive focus positions, then computing the surface roughness. Extended-focus reconstruction has been used to explain the behavior along fracture surface. Since these techniques are based on light microscopy, their inherent low cost is very interesting for failure investigations. (orig.) [German] Diese Arbeit ist ein Beispiel fuer die Verbesserung der quantitativen Fraktographie mittels digitaler Bildverarbeitung und Lichtmikroskopie. Zur Untersuchung des quantitativen Bruchverhaltens von waermebehandelten Ti-4Al-4V-Proben im Charpy-Kerbschlagversuch werden zwei Techniken vorgestellt. Die erste Technik ist die Minkowski-Methode zur Messung der fraktalen Dimensionen aus Oberflaechenprofilen, welche den multifraktalen Charakter des Bruches von Ti-4Al-4V ergibt. Es wurde keine eindeutige positive Korrelation zwischen den fraktalen Werten und den Charpyenergien der Ti-4Al-4V-Proben aufgrund deren Duktilitaet, Gefuegeheterogenitaeten und dynamischen Belastungscharakteristiken im Bereich um den V-Kerb beobachtet. Die zweite Methode bietet eine vollstaendige Erhoehungsabbildung der Bruchoberflaeche durch Extraktion der Fokusierungsbereiche

  6. The cryogenic bonding evaluation at the metallic-composite interface of a composite overwrapped pressure vessel with additional impact investigation

    Science.gov (United States)

    Clark, Eric A.

    A bonding evaluation that investigated the cryogenic tensile strength of several different adhesives/resins was performed. The test materials consisted of 606 aluminum test pieces adhered to a wet-wound graphite laminate in order to simulate the bond created at the liner-composite interface of an aluminum-lined composite overwrapped pressure vessel. It was found that for cryogenic applications, a flexible, low modulus resin system must be used. Additionally, the samples prepared with a thin layer of cured resin -- or prebond -- performed significantly better than those without. It was found that it is critical that the prebond surface must have sufficient surface roughness prior to the bonding application. Also, the aluminum test pieces that were prepared using a surface etchant slightly outperformed those that were prepared with a grit blast surface finish and performed significantly better than those that had been scored using sand paper to achieve the desired surface finish. An additional impact investigation studied the post impact tensile strength of composite rings in a cryogenic environment. The composite rings were filament wound with several combinations of graphite and aramid fibers and were prepared with different resin systems. The rings were subjected to varying levels of Charpy impact damage and then pulled to failure in tension. It was found that the addition of elastic aramid fibers with the carbon fibers mitigates the overall impact damage and drastically improves the post-impact strength of the structure in a cryogenic environment.

  7. Effects of manufacturing process on impact properties and microstructures of ODS steels

    Energy Technology Data Exchange (ETDEWEB)

    Tanno, Takashi, E-mail: tanno.takashi@jaea.go.jp; Ohtsuka, Satoshi; Yano, Yasuhide; Kaito, Takeji; Tanaka, Kenya

    2014-12-15

    Oxide dispersion strengthened (ODS) steels are notable advanced alloys with durability to a high-temperature and high-dose neutron irradiation environment because of their good swelling resistance and mechanical properties under neutron irradiation. 9–12Cr-ODS martensite steels have been developed in the Japan Atomic Energy Agency as the primary candidate material for the fast reactor fuel cladding tubes. They would also be good candidates for the fusion reactor blanket material which is exposed to high-dose neutron irradiation. In this work, modification of the manufacturing process of 11Cr-ODS steel was carried out to improve its impact property. Two types of 11Cr-ODS steels were manufactured: pre-mix and full pre-alloy ODS steels. Miniature Charpy impact tests and metallurgical observations were carried out on these steels. The impact properties of full pre-alloy ODS steels were shown to be superior to those of pre-mix ODS steels. It was demonstrated that the full pre-alloy process noticeably improved the microstructure homogeneity (i.e. reduction of inclusions and pores)

  8. Format Guide for Scientific and Technical Reports.

    Science.gov (United States)

    1984-01-01

    Beta B / Kappa K K Sigma I (r Gamma r , Lambda A X Tau T 7 S Delta a 8 Mu M p Upsilon Y v Epsilon E E Nu N v Phi 4 Zeta Z C Xi f Chi X X Eta H 71...crytallographic centrifugal cumulant Cerenkov, Cherenkov cumulus cesium cure-all chain -reacting pile cut (use cap. letter and no hyphen for Charpy V-notch...one word) • lifetime minelayer lighter-than-air craft minesweeper lightweight minimum, minima light -year mismatch .. like (combines to form one mockup

  9. Study of Six-Component Internal Strain Gage Balances for Use in the HIRT Facility

    Science.gov (United States)

    1975-07-01

    bridges, also provides a backlog of s t ress information on which to base this study. The two-shell balance has been an important instrument in the...Reference 1) Ftu (ksi) 300 Fty (ksi) 280 Fsu (ksi) 170 Elongation (%) 5 E (106 psi) 27,0 G (106psi) 10.2 Charpy V-notch (ft-lb) 17 KIC (ksi ~-n...varying BMC location can be used to attain higher normal force for given runs, thus allowing for more test points. Figure 7 is a graphic

  10. Ductile growth of crack like flawing during hydrotest; Propagacao dutil de defeitos planares durante teste hidrostatico

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Jose C.; Donato, Guilherme V. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES); Silva, Marcinei S. da; Bastian, Fernando L. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE); Lima, Romulo S. de [PETROBRAS/AB-RE, Rio de Janeiro, RJ (Brazil)

    2003-07-01

    In this paper effects of hydrostatic testing on ductile propagation of crack like flaw defects were evaluated in API X-60 steel. The model used was based on the J-tearing theory, supported by elastic - plastic fracture mechanics. The J-initiation resistance values (JIc) were determined by fracture mechanic tests using potential drop technique and compact test specimen. The JIc values were also determined from flow stress and Charpy V-notch at plateau, which are both usually available in mill-test data. Despite of being based on small database it seems it could be extended and it will be useful for future analysis. (author)

  11. Enhancement of Impact Toughness by Delamination Fracture in a Low-Alloy High-Strength Steel with Al Alloying

    Science.gov (United States)

    Sun, Junjie; Jiang, Tao; Liu, Hongji; Guo, Shengwu; Liu, Yongning

    2016-12-01

    The effect of delamination toughening of martensitic steel was investigated both at room and low temperatures [253 K and 233 K (-20 °C and -40 °C)]. Two low-alloy martensitic steels with and without Al alloying were both prepared. Layered structure with white band and black matrix was observed in Al alloyed steel, while a homogeneous microstructure was displayed in the steel without Al. Both steels achieved high strength (tensile strength over 1600 MPa) and good ductility (elongation over 11 pct), but they displayed stark contrasts on impact fracture mode and Charpy impact energy. Delamination fracture occurred in Al alloyed steel and the impact energies were significantly increased both at room temperature (from 75 to 138 J, i.e., nearly improved up to 2 times) and low temperatures [from 47.9 to 71.3 J at 233 K (-40 °C)] compared with the one without Al. Alloying with Al promotes the segregation of Cr, Mn, Si and C elements to form a network structure, which is martensite with higher carbon content and higher hardness than that of the matrix. And this network structure evolved into a band structure during the hot rolling process. The difference of yield stress between the band structure and the matrix gives rise to a delamination fracture during the impact test, which increases the toughness greatly.

  12. Enhancement of Impact Toughness by Delamination Fracture in a Low-Alloy High-Strength Steel with Al Alloying

    Science.gov (United States)

    Sun, Junjie; Jiang, Tao; Liu, Hongji; Guo, Shengwu; Liu, Yongning

    2016-09-01

    The effect of delamination toughening of martensitic steel was investigated both at room and low temperatures [253 K and 233 K (-20 °C and -40 °C)]. Two low-alloy martensitic steels with and without Al alloying were both prepared. Layered structure with white band and black matrix was observed in Al alloyed steel, while a homogeneous microstructure was displayed in the steel without Al. Both steels achieved high strength (tensile strength over 1600 MPa) and good ductility (elongation over 11 pct), but they displayed stark contrasts on impact fracture mode and Charpy impact energy. Delamination fracture occurred in Al alloyed steel and the impact energies were significantly increased both at room temperature (from 75 to 138 J, i.e., nearly improved up to 2 times) and low temperatures [from 47.9 to 71.3 J at 233 K (-40 °C)] compared with the one without Al. Alloying with Al promotes the segregation of Cr, Mn, Si and C elements to form a network structure, which is martensite with higher carbon content and higher hardness than that of the matrix. And this network structure evolved into a band structure during the hot rolling process. The difference of yield stress between the band structure and the matrix gives rise to a delamination fracture during the impact test, which increases the toughness greatly.

  13. Effects of Zr, Ti, and Al Additions on Nonmetallic Inclusions and Impact Toughness of Cast Low-Alloy Steel

    Science.gov (United States)

    Bizyukov, Pavel V.; Giese, Scott R.

    2017-03-01

    A microalloying of the low-carbon and low-alloy cast steel was conducted with Zr, Ti, and Al that were added to the steel in four combinations. After heat treatment, the samples were tested for impact toughness at room temperature using the Charpy method. The highest values of impact toughness were obtained in the group treated with Zr, while Zr-Ti and Zr-Ti-Al groups showed moderate toughness values; the lowest values were observed in the Zr-Al group. Difference among the treatment groups was observed in the fracture mechanisms, morphology, and area distribution of the inclusions. High toughness values achieved in the trials treated with zirconium corresponded with smooth ductile fracture. The metal treated with a combination of zirconium and titanium had a relatively small area occupied by inclusions, but its toughness was also moderate. Lowest impact toughness values corresponded with the larger area occupied by the inclusions in the trials treated with aluminum. Also, a connection between the solubility product [Al][N] and impact toughness was established. The study also provides a qualitative description and quantitative analysis of the nonmetallic inclusions formation as a result of microalloying treatment. The precipitation sequence of the inclusions was described based on the thermochemical calculations for the nonmetallic compounds discovered in the experimental steel. A description of the size distribution, morphology, and composition was conducted for the oxides, nitrides, sulfides, and multiphase particles.

  14. Study on impact properties of creep-resistant steel thermally simulated heat affected zone

    Directory of Open Access Journals (Sweden)

    Mitrović Radivoje M.

    2012-01-01

    Full Text Available The steam pipe line (SPL and steam line material, along with its welded joints, subject to damage that accumulates during operation in coal power plants. As a result of thermal fatigue, dilatation of SPL at an operating temperature may lead to cracks initiation at the critical zones within heat affected zone (HAZ of steam pipe line welded joints. By registration of thermal cycle during welding and subsequent HAZ simulation is possible to obtain target microstructure. For the simulation is chosen heat resisting steel, 12H1MF (designation 13CrMo44 according to DIN standard. From the viewpoint of mechanical properties, special attention is on impact toughness mostly because very small number of available references. After simulation of single run and multi run welding test on instrumented Charpy pendulum. Metallographic and fractographic analysis is also performed, on simulated 12H1MF steel from service and new, unused steel. The results and correlation between microstructure and impact toughness is discussed, too.

  15. Impact characteristics of austempered spheroidal graphite cast steel. Austemper kyujo kokuen chuko no shogeki tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, T.; Tada, S.; Abe, T. (Government Industrial Research Institute, Tohoku, Sendai (Japan))

    1993-08-25

    Austempered ductile cast iron (ADI) has excellent mechanical properties both in strength and toughness, but the Young's modulus of ADI is lower than that of steel because ADI contains much graphite. In order to obtain better mechanical properties than ADI, spheroidal graphite cast steel containing less graphite by volume was austempered. The Young's modulus of austempered spheroidal graphite cast steel (AGS) was 200 GPa, which was comparable to steel. The retained austenite volume of the sample containing 2.4% Si varied with the austempering conditions, but that of the sample containing 1.4% Si decreased in a shorter austempered time. As a result, it was found that Si affects stability of the retained austenite. Charpy impact value increased with increasing the retained austenite volume when the volume was above 15%. The impact value of AGS with 40% retained austenite was over twice as large as that of ADI austempered under the same conditions. 21 refs., 8 figs., 1 tab.

  16. Characteristic of retained austenite decomposition during tempering and its effect on impact toughness in SA508 Gr.3 steel

    Science.gov (United States)

    Yan, Guanghua; Han, Lizhan; Li, Chuanwei; Luo, Xiaomeng; Gu, Jianfeng

    2017-01-01

    Retained austenite(RA) usually presents in the quenched Nuclear Pressure-Vessel SA508 Gr.3 steel. In the present work, the characteristic of RA decomposition and its effect on the impact toughness were investigated by microstructure observation, dilatometric experiments and Charpy impact tests. The results show that the RA transformed into martensite and bainite during tempering at 230 °C and 400 °C respectively, while mixture of long rod carbides and ferrite formed at 650 °C. The long rod carbides formed from RA decomposition decrease the critical cleavage stress for initiation of micro-cracks, and deteriorate the impact toughness of the steel. Pre-tempering at a low temperature such as 230 °C or 400 °C leading to the decomposition of RA into martensite or baintie can eliminate the deterioration of the toughness caused by direct decomposition into long rod carbides. The absorbed energy indicate that pre-tempering at 400 °C can drive dramatically improvement in the toughness of the steel.

  17. Enhanced Thermal Performance and Impact Strength of UHMWPE/Recycled-PA6 Blends Synthesized via a Melting Extrusion Route

    Directory of Open Access Journals (Sweden)

    Xiuying Yang

    2016-01-01

    Full Text Available The blends of ultra-high molecular weight polyethylene (UHMWPE and recycled-polyamide 6 (R-PA6 were prepared via a melting extrusion route using high-density polyethylene-graft-maleic anhydride (HDPE-g-MAH as the compatibilizer. The morphologies and distributions of the chemical components of the blends were characterized by scanning electron microscopy and synchrotron Fourier transform infrared microspectroscopy. The effects of R-PA6 content on the Vicat softening temperature (VST, heat distortion temperature (HDT, and impact strength of the blends were studied. Remarkably, in comparison with those of UHMWPE, the VST and HDT of UHMWPE/R-PA6 blends with 44 wt% R-PA6 were increased to 165.1 and 98.4°C, respectively, and the Charpy impact strength and Izod impact strength of the blends were enhanced to 33.9 and 16.2 kJ/m2, respectively. In addition, it was found that the blending system containing 44 wt% R-PA6 and 48 wt% UHMWPE exhibited the best compatibility when it was prepared using 8 wt% HDPE-g-MAH. The distribution of the phases of UHMWPE and R-PA6 was uniform, and no obvious phase separation was observed in the blends.

  18. Influence of Heat Input on Martensite Formation and Impact Property of Ferritic-Austenitic Dissimilar Weld Metals

    Institute of Scientific and Technical Information of China (English)

    M. Mukherjee; T.K. Pal

    2012-01-01

    The effect of heat input on martensite formation and impact properties of gas metal arc welded modified ferritic stainless steel (409M) sheets (as received) with thickness of 4 mm was described in detail in this work. The welded joints were prepared under three heat input conditions, i.e. 0.4, 0.5 and 0.6 kJ/mm using two different austenitic filler wires (308L and 316L) and shielding gas composition of Ar + 5% CO2. The welded joints were evaluated by microstructure and charpy impact toughness. The dependence of weld metal microstructure on heat input and filler wires were determined by dilution calculation, Creq/Nieq ratio, stacking fault energy (SFE), optical microscopy (OM) and transmission electron microscopy (TEM). It was observed that the microstructure as well as impact property of weld metal was significantly affected by the heat input and filler wire. Weld metals prepared by high heat input exhibited higher amount of martensite laths and toughness compared with those prepared by medium and low heat inputs, which was true for both the filler wires. Furthermore, 308L weld metals in general provided higher amount of martensite laths and toughness than 316L weld metals.

  19. An Experimental Technique for Developing Intermediate Strain Rates in Ductile Metals

    Science.gov (United States)

    2008-03-01

    Instrumented Charpy tests rely on a strain gage instrumented load cell to col- lect a load-history during impact. However, the same fundamental limitations due...to wave-propagation and inertia effects are inherent in the instrumented Charpy test , as other instrumented impact tests , limiting the velocities at...lower velocities, the instrumentation of the Charpy test has transformed it from an al- most purely subjective impact survivability test to

  20. Subtask 12D1: Impact properties of production heat of V-4Cr-4Ti

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.M.; Nowicki, L.; Smith, D.L. [Argonne National Lab., IL (United States)

    1995-03-01

    Following previous reports of excellent properties of a laboratory heat of V-4Cr-4Ti, the alloy identified as the primary vanadium-based candidate for application as fusion reactor structural components, a large production-scale (500-kg) heat of the alloy was fabricated successfully. Since impact toughness has been known to be most sensitive to alloy composition and microstructure, impact testing of the production-scale heat was conducted in this work between -200{degrees}C and +200{degrees}C. A 500-kg heat of V-4Cr-4Ti, an alloy identified previously as the primary vanadium-based candidate alloy for application as fusion reactor structural components, has been produced successfully. Impact tests were conducted at -196{degrees}C to 150{degrees}C on 1/3-size Charpy specimens of the scale-up heat in as-rolled condition and after annealing for 1 h at 950, 1000, and 1050{degrees}C in high-quality vacuum. The annealed material remained ductile at all test temperatures; the ductile-brittle transition temperature (DBTT) was lower than -200{degrees}C. The upper-shelf energy of the production-scale heat was similar to that of the laboratory-scale ({approx}30-kg) heat of V-4Cr-4Ti investigated previously. Effect of annealing temperature was not significant; however, annealing at 1000{degrees}C for 1 h not only produces best impact properties but also ensures a sufficient tolerance to effect of temperature inhomogeneity expected when annealing large components. Effect of notch geometry was also investigated on the production heat. When annealed properly (e.g., at 1000{degrees}C for 1 h), impact properties were not sensitive to notch geometry (45{degrees}-notch, root radius 0.25 mm; and 300-notch, root radius 0.08 mm). 11 refs., 6 figs., 1 tab.

  1. High Manganese and Aluminum Steels for the Military and Transportation Industry

    Science.gov (United States)

    Bartlett, Laura; Van Aken, David

    2014-09-01

    Lightweight advanced high strength steels (AHSS) with aluminum contents between 4 and 12 weight percent have been the subject of intense interest in the last decade because of an excellent combination of high strain rate toughness coupled with up to a 17% reduction in density. Fully austenitic cast steels with a nominal composition of Fe-30%Mn-9%Al-0.9%C are almost 15% less dense than quenched and tempered Cr-Mo steels (SAE 4130) with equivalent strengths and dynamic fracture toughness. This article serves as a review of the tensile and high-strain-rate fracture properties associated mainly with silicon additions to this base composition. In the solution-treated condition, cast steels have high work-hardening rates with elongations up to 64%, room-temperature Charpy V-notch (CVN) impact energies up to 200 J, and dynamic fracture toughness over 700 kJ/m2. Silicon additions in the range of 0.59-1.56% Si have no significant effect on the mechanical properties of solution-treated steels but increased the tensile strength and hardness during aging. For steels aged at 530°C to an average hardness of 310 Brinell hardness number, HBW, increasing the amount of silicon from 1.07% to 1.56% decreased the room temperature CVN breaking energy from 92 J to 68 J and the dynamic fracture toughness from 376 kJ/m2 to 265 kJ/m2. Notch toughness is a strong function of phosphorus content, decreasing the solution-treated CVN impact toughness from 200 J in a 0.006% P steel to 28 J in a 0.07% P steel. For age-hardened steels with 1% Si, increasing levels of phosphorus from 0.001% to 0.043% decreased the dynamic fracture toughness from 376 kJ/m2 to 100 kJ/m2.

  2. Impact behavior of reduced-activation steels irradiated to 24 dpa

    Energy Technology Data Exchange (ETDEWEB)

    Klueh, R.L.; Alexander, D.J. [Oak Ridge National Laboratory, TN (United States)

    1996-04-01

    Charpy impact properties of eight reduced-activation Cr-W ferritic steels were determined after irradiation to {approx}21-24 dpa in the Fast Flux Test Facility (FFTF) at 365{degree}C. Chromium concentrations in the eight steels ranged from 2.25 to 12wt% Cr (steels contained {approx}0.1%C). the 2 1/4Cr steels contained variations of tungsten and vanadium, and the steels with 5, 9, and 12% Cr, contained a combination of 2% W and 0.25% V. A 9Cr in FFTF to {approx}6-8 and {approx}15-17 dpa. Irradiation caused an increase in the DBTT and decrease in the USE, but there was little further change in the DBTT from that observed after the 15-17 dpa irradiation, indicating that the shift had essentially saturated with fluence. The results are encouraging because they indicate that the effect of irradiation on toughness can be faorably affected by changing composition and microstructure.

  3. STUDY ON THE EXPERIMENTAL TECHNIQUES OF DYNAMIC FRACTURE TOUGHNESS OF MATERIALS BASED ON INSTRUMENTED CHARPY IMPACT TEST%基于示波冲击实验材料动态断裂韧度测试技术的研究

    Institute of Scientific and Technical Information of China (English)

    许振琦; 朱世范; 果春焕; 王延春; 姜风春

    2015-01-01

    采用预裂纹Charpy冲击试样,基于示波冲击试验建立了测试材料动态断裂韧度的试验方法.与以往预裂纹试样动态应力强度因子的计算方法不同,采用Timoshenko梁理论,提出了一种简单方法来计算三点弯曲试样的刚度K(a),由此建立了三点弯曲试样动态应力强度因子的计算方法,通过实验测得启裂时间,从而确定动态断裂韧度.采用有限元方法对试样动态应力强度因子的理论计算方法进行了验证.结果表明,建立的计算方法准确、可靠,避免了复杂的数值计算,便于工程应用.

  4. Genital impacts Genital impacts

    Directory of Open Access Journals (Sweden)

    Luiz Felipe G Soares

    2008-04-01

    Full Text Available I propose to analyze three images of genitalia from three different films that do not have sex as their central subject: (1 Lígia’s (Leona Cavalli’s vulva in Claudio Assis’s Amarelo Manga (Brazil, 2002, (2 Stoffer’s (Jens Albinus’s erect penis in Lars von Trier’s The Idiots (Denmark, 1998, and (3 transsexual Dil’s (Jaye Davidson’s penis in Neil Jordan’s The Crying Game (USA, 1992. All three images are explicit and surprising enough to provoke impact, both in diegetic and extra-diagetic spaces. intend to compare the three images and investigate the nature of their impacts, not directly in terms of morality, but in their relation with two theoretical assumptions: (1 the intense way in which, according to Linda Nicholson (1999, so many cultures insist in interpreting bodies and genitalia as still capable of defining gender characters, and (2 the notion of image, not as representation, but as image itself, as “what it is”, or as “the place of every transformation in the universe”, as suggested first by Bergson (2005, and then by Deleuze (1983-5, Rancière (2001 and Agamben (1995. The Deleuzean retard may indicate the way in which genitalia, as image, turn into enigma, in the very passage from nature to culture. The three shots give back to those clear images of genitalia the property they have always had: their character of central pieces in the game of such passage. The contrast between such simple and clear images and all those complex games corresponds to the nature of the impact I want to investigate. film; genitalia; narrative. I propose to analyze three images of genitalia from three different films that do not have sex as their central subject: (1 Lígia’s (Leona Cavalli’s vulva in Claudio Assis’s Amarelo Manga (Brazil, 2002, (2 Stoffer’s (Jens Albinus’s erect penis in Lars von Trier’s The Idiots (Denmark, 1998, and (3 transsexual Dil’s (Jaye Davidson’s penis in Neil Jordan’s The Crying Game (USA

  5. An Investigation on the Wear Resistance and Fatigue Behaviour of Ti-6Al-4V Notched Members Coated with Hydroxyapatite Coatings

    Directory of Open Access Journals (Sweden)

    Reza H Oskouei

    2016-02-01

    Full Text Available In this study, surface properties of Ti-6Al-4V alloy coated with hydroxyapatite coatings were investigated. Wear resistance and fatigue behaviour of samples with coating thicknesses of 10 and 50 µm as well as uncoated samples were examined. Wear experiments demonstrated that the friction factor of the uncoated titanium decreased from 0.31 to 0.06, through a fluctuating trend, after 50 cycles of wear tests. However, the friction factor of both the coated samples (10 and 50 µm gradually decreased from 0.20 to 0.12 after 50 cycles. At the end of the 50th cycle, the penetration depth of the 10 and 50 µm coated samples were 7.69 and 6.06 µm, respectively. Fatigue tests showed that hydroxyapatite coatings could improve fatigue life of a notched Ti-6Al-4V member in both low and high cycle fatigue zones. It was understood, from fractography of the fracture surfaces, that the fatigue zone of the uncoated specimens was generally smaller in comparison with that of the coated specimens. No significant difference was observed between the fatigue life of coated specimens with 10 and 50 µm thicknesses.

  6. Production and fabrication of vanadium alloys for the radiative divertor program of DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, W.R.; Smith, J.P.; Stambaugh, R.D.

    1996-04-01

    V-4Cr-4-Ti alloy has been recently selected for use in the manufacture of a portion of the DIII-D Radiative Divertor modification, as part of an overall DIII-D vanadium alloy deployment effort developed by General Atomics (GA) in conjunction with the Argonne and Oak Ridge National Laboratories (ANL or ORNL). The goal of this work is to produce a production-scale heat of the alloy and fabricate it into product forms for the manufacture of a portion of the Radiative Divertor (RD) for the DIII-D tokamak, to develop the fabrications technology for manufacture of the vanadium alloy radiative Divertor components, and to determine the effects of typical tokamak environments in the behavior of the vanadium alloy. The production of a {approx}1300-kg heat of V-4Cr-4Ti alloy is currently in progress at Teledyne Wah Chang of Albany, oregon (TWCA) to provide sufficient material for applicable product forms. Two unalloyed vanadium ingots for the alloy have already been produced by electron beam melting of raw processes vanadium. Chemical compositions of one ingot and a portion of the second were acceptable, and Charpy V-Notch (CVN) impact test performed on processed ingot samples indicated ductile behavior. Material from these ingots are currently being blended with chromium and titanium additions, and will be vacuum-arc remelted into a V-4Cr-4Ti alloy ingot and converted into product forms suitable for components of the DIII-D RD structure. Several joining methods selected for specific applications in fabrication of the RD components are being investigated, and preliminary trials have been successful in the joining of V-alloy to itself by both resistance and inertial welding processes and to Inconel 625 by inertial welding.

  7. 17-4PH马氏体不锈钢350℃长期时效脆化研究%Study on Aging Embrittlement of 17-4PH Martensite Stainless Steel at 350℃

    Institute of Scientific and Technical Information of China (English)

    王均; 邹红; 伍晓勇; 邱绍宇; 沈保罗

    2005-01-01

    采用光学显微镜(OM)、扫描电镜(SEM)、硬度测定以及示波冲击试验(instrumental impact test)研究了17-4PH马氏体不锈钢在350℃长期时效过程中显微组织、硬度、冲击韧性以及断口形貌的变化规律.结果表明:该马氏体不锈钢在350℃长期时效的过程中,随着时效时间的延长,其硬度升高,并在时效9000h时达到最大值;其裂纹萌生功(Ei),裂纹扩展功(Ep)和总冲击功(Et)都随时效时间的延长而逐渐下降.根据示波冲击曲线获得了17-4PH马氏体不锈钢的动态断裂韧性Kid,其动态断裂韧性也表现出和Ei,Ep及Et相类似的变化规律.该不锈钢的夏氏V型缺口(Charpy V-notch)冲击试样断口形貌随着时效时间的延长由韧窝断裂为主向准解理断裂和沿晶断裂为主变化.

  8. Effect of composition and processing on the thermal fatigue and toughness of high performance die steels. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, J.F.; Wang, Y.; Schwam, D.

    1997-06-01

    The objective of this study was to improve average die life by optimizing die steel composition and the die processing. Four different steels, K,Q,C and Premium Grade H-13 have been investigated for thermal fatigue resistance and toughness. Optimum heat treatment processing has been determined for each steel with respect to austenitizing temperature and tempering conditions. The effect of the quenching rate on the thermal fatigue resistance and toughness of the die steels and the effect of Electro-Discharge Machining (EDM) on the thermal fatigue resistance were also determined. The immersion thermal fatigue specimen developed at CWRU was used to determine the thermal fatigue resistance as characterized by the two parameters of average maximum crack length and total crack area. The Charpy V-notch impact test was used over a -100{degrees}F to 450{degrees}F testing temperature range to evaluate the toughness and the brittle-ductile transition behavior. K steel has been identified as superior in performance compared to Premium Grade H-13. Q and C provide lower toughness and thermal fatigue resistance than H-13. Faster cooling rates provide higher thermal fatigue resistance and toughness. Higher austenitizing temperatures such as 1925{degrees}F compared to 1875{degrees}F provide better thermal fatigue resistance, but lower austenitizing temperatures of 1875{degrees}F provide better toughness. Higher hardness improves thermal fatigue resistance, but reduces toughness. A minimum of Rc 46 hardness is desired for aluminum die casting dies. EDM reduces the thermal fatigue resistance compared to conventional machining operations. When the EDM process of multiple small steps of decreasing energy and post-EDM treatments are employed, the effect can be reduced to a very slight amount. Preliminary evidence of the superior performance of the K steel has been provided by ongoing field testing of inserts in multiple cavity dies.

  9. Injection moulding of long glass fibre reinforced poly(ethylene terephtalate: Influence of carbon black and nucleating agents on impact properties

    Directory of Open Access Journals (Sweden)

    E. Lafranche

    2012-09-01

    Full Text Available This paper aims at highlighting the influence of different additives (carbon black and nucleating agents on both the notched and unnotched Charpy impact properties of long glass fibre reinforced poly(ethylene terephtalate injection mouldings. The relationship with the polymer matrix and composite microstructure modifications (variations of crystalline morphology and local fibre content was investigated. Adding carbon black alone decreases the impact performances. This highly conductive additive actually increases the cooling rate, and therefore the fibre ‘frettage’ effect (higher internal stresses. It also acts as filler, which increases the material brittleness. The nucleating agents allow reducing the mould temperature, but their effect on the impact strength may be favourable or not depending on the processing temperatures. The addition of such additives induces perturbations of the polymer melt rheology in the mould cavity and of the cooling kinetics of the part, which both act on the fibre distribution during mould filling and on the degree of crystallinity of the composite parts.

  10. Impact properties of electron beam welds of V–4Ti–4Cr alloys NIFS-HEAT-2 and CEA-J57

    Energy Technology Data Exchange (ETDEWEB)

    Tsisar, Valentyn, E-mail: valentyn_tsisar@ipm.lviv.ua [National Institute for Fusion Science (NIFS), 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Physical–Mechanical Institute of National Academy of Sciences of Ukraine (PhMI NASU), 5 Naukova Street, 79601 Lviv (Ukraine); Karlsruhe Institute of Technology (KIT), Institute for Applied Materials – Material Process Technology (IAM-WPT), Hermann-von-Helmholtz-Platz, 1, 76344 Eggenstein-Leopoldshafen (Germany); Nagasaka, Takuya [National Institute for Fusion Science (NIFS), 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Le Flem, Marion [CEA, DEN, DMN, SRMA, F-91191 Gif Sur Yvette (France); Yeliseyeva, Olga [Physical–Mechanical Institute of National Academy of Sciences of Ukraine (PhMI NASU), 5 Naukova Street, 79601 Lviv (Ukraine); Konys, Jürgen [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials – Material Process Technology (IAM-WPT), Hermann-von-Helmholtz-Platz, 1, 76344 Eggenstein-Leopoldshafen (Germany); Muroga, Takeo [National Institute for Fusion Science (NIFS), 322-6 Oroshi, Toki, Gifu 509-5292 (Japan)

    2014-10-15

    Highlights: • Electron beam welding was applied for V–4Ti–4Cr alloys NIFS-HEAT-2 and CEA-J57. • Weld metal showed superior impact properties in comparison with base metal. • Expected shift in DBTT to higher temperatures does not take place. - Abstract: The Charpy impact properties and microstructure of bead-on-plate electron beam welds of V–4Ti–4Cr alloys NIFS-HEAT-2 (NH-2) and CEA-J57 (J57) were investigated. Weld metal of both grades demonstrated increase in hardness (HV{sub 100} ∼ 180) in comparison with base metal (HV{sub 100} ∼ 135) due to decomposition of Ti–C,O,N precipitates followed by the solid-solution hardening of V-matrix with oxygen. Hardness decreases gradually from the weld metal through the heat affected zone toward the base metal indicating partial decomposition of precipitation bands from the side of heat affected zone directly adjoining weld metal. The latter consists of columnar crystallites (grains) possessing with inner dendritic structure and elongated from the center of weld belt in the direction of heat removal. Thickness of weld metal does not exceed 1 mm while heat affected zone is about 3 mm thick. Absorbed energies of weld metal are superior in comparison with base metal for both grades (NH-2 and J57) while the fracture mode is mainly ductile in the temperature range of impact test from 17 to −196 °C.

  11. Impact accelerations

    Science.gov (United States)

    Vongierke, H. E.; Brinkley, J. W.

    1975-01-01

    The degree to which impact acceleration is an important factor in space flight environments depends primarily upon the technology of capsule landing deceleration and the weight permissible for the associated hardware: parachutes or deceleration rockets, inflatable air bags, or other impact attenuation systems. The problem most specific to space medicine is the potential change of impact tolerance due to reduced bone mass and muscle strength caused by prolonged weightlessness and physical inactivity. Impact hazards, tolerance limits, and human impact tolerance related to space missions are described.

  12. The evaluation of dynamic cracking resistance of chosen casting alloys in the aspect of the impact bending test

    Directory of Open Access Journals (Sweden)

    J.Sadowski

    2008-10-01

    Full Text Available The increase of quality and durability of produced casting alloys can be evaluated on the base of material tests performed on a high level. One of such modern test methods are tests of the dynamic damage process of materials and the evaluation on the base of obtained courses F(f, F(t of parameters of dynamic cracking resistance KId, JId, performed with the usage of instrumented Charpy pendulums. In the paper there was presented the evaluation of dynamic cracking resistance parameters of casting alloys such as: AK12 aluminum alloy, L20G cast steel and spheroid cast iron. The methodology of the evaluation of that parameters was described and their change as well, for the AK12 alloy with the cold work different level, L20G cast steel cooled from different temperatures in the range +20oC -60oC, and for the spheroid cast iron in different stages of treatment i.e. raw state, after normalization, spheroid annealing and graphitizing annealing.Obtained parameters of dynamic cracking resistance KId, JId of tested casting alloys enabled to define the critical value of the ad defect that can be tolerated by tested castings in different work conditions with impact loadings.

  13. Heat treatment effects on impact toughness of 9Cr-1MoVNb and 12Cr-1MoVW steels irradiated to 100 dpa

    Energy Technology Data Exchange (ETDEWEB)

    Klueh, R.L.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)

    1997-08-01

    Plates of 9Cr-1MoVNb and 12Cr-1MoVW steels were given four different heat treatments: two normalizing treatments were used and for each normalizing treatment two tempers were used. Miniature Charpy specimens from each heat treatment were irradiated to {approx}19.5 dpa at 365{degrees}C and to {approx}100 dpa at 420{degrees}C in the Fast Flux Test Facility (FFTF). In previous work, the same materials were irradiated to 4-5 dpa at 365{degrees}C and 35-36 dpa at 420{degrees}C in FFTF. The tests indicated that prior austenite grain size, which was varied by the different normalizing treatments, had a significant effect on impact behavior of the 9Cr-1MoVNb but not on the 12Cr-1MoVW. Tempering treatment had relatively little effect on the shift in DBTT for both steels. Conclusions are presented on how heat treatment can be used to optimize impact properties.

  14. SCK-CEN Contribution to the''Relation between different measures of exposure-induced shifts in ductile-brittle transition temperatures'' (REFEREE). Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Chaouadi, R.; Van Walle, E.; Fabry, A.; Puzzolante, J.L

    1998-08-01

    The relationship between Charpy-V (CVN) impact, fracture toughness and tensile properties for selected reactor pressure -vessel steels in the transition temperature range are investigated. Data on the testing of unirradiated material are reported. The applied methods include chemical analysis, Charpy-V impact testing, tensile testing and fracture toughness determination.

  15. Final Report, Volume 2, The Development of Qualification Standards for Cast Duplex Stainless Steel

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Steven, W.; Lundin, Carl, D.

    2005-09-30

    The scope of testing cast Duplex Stainless Steel (DSS) required testing to several ASTM specifications, while formulating and conducting industry round robin tests to verify and study the reproducibility of the results. ASTM E562 (Standard Test Method for Determining Volume Fraction by Systematic manual Point Count) and ASTM A923 (Standard Test Methods for Detecting Detrimental Intermetallic Phase in Wrought Duplex Austenitic/Ferritic Stainless Steels) were the specifications utilized in conducting this work. An ASTM E562 industry round robin, ASTM A923 applicability study, ASTM A923 industry round robin, and an ASTM A923 study of the effectiveness of existing foundry solution annealing procedures for producing cast DSS without intermetallic phases were implemented. In the ASTM E562 study, 5 samples were extracted from various cast austenitic and DSS in order to have varying amounts of ferrite. Each sample was metallographically prepared by UT and sent to each of 8 participants for volume fraction of ferrite measurements. Volume fraction of ferrite was measured using manual point count per ASTM E562. FN was measured from the Feritescope{reg_sign} and converted to volume fraction of ferrite. Results indicate that ASTM E562 is applicable to DSS and the results have excellent lab-to-lab reproducibility. Also, volume fraction of ferrite conversions from the FN measured by the Feritescope{reg_sign} were similar to volume fraction of ferrite measured per ASTM E562. In the ASTM A923 applicability to cast DSS study, 8 different heat treatments were performed on 3 lots of ASTM A890-4A (CD3MN) castings and 1 lot of 2205 wrought DSS. The heat treatments were selected to produce a wide range of cooling rates and hold times in order to study the suitability of ASTM A923 to the response of varying amounts on intermetallic phases [117]. The test parameters were identical to those used to develop ASTM A923 for wrought DSS. Charpy V-notch impact samples were extracted from the

  16. Final Report, Volume 2, The Development of Qualification Standards for Cast Duplex Stainless Steel

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Steven, W.; Lundin, Carl, W.

    2005-09-30

    The scope of testing cast Duplex Stainless Steel (DSS) required testing to several ASTM specifications, while formulating and conducting industry round robin tests to verify and study the reproducibility of the results. ASTM E562 (Standard Test Method for Determining Volume Fraction by Systematic manual Point Count) and ASTM A923 (Standard Test Methods for Detecting Detrimental Intermetallic Phase in Wrought Duplex Austenitic/Ferritic Stainless Steels) were the specifications utilized in conducting this work. An ASTM E562 industry round robin, ASTM A923 applicability study, ASTM A923 industry round robin, and an ASTM A923 study of the effectiveness of existing foundry solution annealing procedures for producing cast DSS without intermetallic phases were implemented. In the ASTM E562 study, 5 samples were extracted from various cast austenitic and DSS in order to have varying amounts of ferrite. Each sample was metallographically prepared by UT and sent to each of 8 participants for volume fraction of ferrite measurements. Volume fraction of ferrite was measured using manual point count per ASTM E562. FN was measured from the Feritescope® and converted to volume fraction of ferrite. Results indicate that ASTM E562 is applicable to DSS and the results have excellent lab-to-lab reproducibility. Also, volume fraction of ferrite conversions from the FN measured by the Feritescope® were similar to volume fraction of ferrite measured per ASTM E562. In the ASTM A923 applicability to cast DSS study, 8 different heat treatments were performed on 3 lots of ASTM A890-4A (CD3MN) castings and 1 lot of 2205 wrought DSS. The heat treatments were selected to produce a wide range of cooling rates and hold times in order to study the suitability of ASTM A923 to the response of varying amounts on intermetallic phases [117]. The test parameters were identical to those used to develop ASTM A923 for wrought DSS. Charpy V-notch impact samples were extracted from the castings and wrought

  17. The impact of hydrograph variability and frequency on the morphodynamics of gravel-bed rivers

    Science.gov (United States)

    Plumb, Ben; Franca, Mário; Juez, Carmelo; Schleiss, Anton; Annable, William

    2016-04-01

    Hydromodification is the alteration of natural watershed hydrologic processes, which is known to change the way that water naturally enters watercourses. In the case of urbanization, this change has manifested through individual hydrograph characteristics (resulting in a decrease in duration and in the time-to-peak), as well as through the increase of the frequency of morphologically significant flood events. These hydrologic changes have been documented to impact the morphology of gravel-bed rivers, often resulting in channel degradation. However, the actual extent that urbanization changes bedload transport characteristics, which is known to be the most important driver of channel morphology, are not yet known. A laboratory experiment was undertaken in a 0.5m gravel-bed flume with sediment feed using a single poorly sorted bimodal sediment mixture in order to evaluate the impacts of changing hydrograph characteristics and frequencies on bedload transport and bed morphology. The hydrograph characteristics and frequencies were derived from long term stream-gauge records of urbanizing gravel-bed watercourses. These records are long enough to therefore be representative of the actual relative changes of the hydrologic regime; from an unaltered to a highly hydromodified system. A series of four hydrologic scenarios were established, representing 10 years of morphologically significant discharge events for four different stages of urban land-use, and corresponding hydrologic regimes. Each scenario begins with the same initial conditions and is allowed to evolve naturally with each successive hydrograph. For each scenario, the hydrograph duration and unsteadiness were varied, while peak discharge remained constant for all scenarios. In addition, the number of hydrographs ranged from nine to 33 for the unaltered to the most hydromodified scenarios, respectively. Discharge was measured constantly with a v-notch weir, and varied with a calibrated valve relationship

  18. Impact beyond the impact factor.

    Science.gov (United States)

    Zupanc, Günther K H

    2014-02-01

    The journal impact factor is an annually calculated number for each scientific journal, based on the average number of times its articles published in the two preceding years have been cited. It was originally devised as a tool for librarians and publishers to provide information about the citation performance of a journal as a whole, but over the last few decades it has increasingly been used to assess the quality of specific articles and the research performance of individual investigators, institutions, and countries. In addition to this clear abuse of the journal impact factor, several conceptual and technical issues limit its usability as a measure of journal reputation, especially when journals are compared across different fields. An author's decision regarding the suitability of a scholarly journal for publication should, therefore, be based on the impact that this journal makes in the field of research, rather than on the journal impact factor.

  19. Economic impact

    Energy Technology Data Exchange (ETDEWEB)

    Technology Transfer Department

    2001-06-01

    In federal fiscal year 2000 (FY00), Berkeley Lab had 4,347 full- and part-time employees. In addition, at any given time of the year, there were more than 1,000 Laboratory guests. These guests, who also reside locally, have an important economic impact on the nine-county Bay Area. However, Berkeley Lab's total economic impact transcends the direct effects of payroll and purchasing. The direct dollars paid to the Lab's employees in the form of wages, salaries, and benefits, and payments made to contractors for goods and services, are respent by employees and contractors again and again in the local and greater economy. Further, while Berkeley Lab has a strong reputation for basic scientific research, many of the Lab's scientific discoveries and inventions have had direct application in industry, spawning new businesses and creating new opportunities for existing firms. This analysis updates the Economic Impact Analysis done in 1996, and its purpose is to describe the economic and geographic impact of Laboratory expenditures and to provide a qualitative understanding of how Berkeley Lab impacts and supports the local community. It is intended as a guide for state, local, and national policy makers as well as local community members. Unless otherwise noted, this analysis uses data from FY00, the most recent year for which full data are available.

  20. Evaluation of ductile-brittle transition behavior with neutron irradiation in nuclear reactor pressure vessel steels using small punch test

    Energy Technology Data Exchange (ETDEWEB)

    Kim, M. C.; Lee, B. S. [KAERI, Taejon (Korea, Republic of); Oh, Y. J. [Hanbat National Univ., Taejon (Korea, Republic of)

    2003-10-01

    A Small Punch (SP) test was performed to evaluate the ductile-brittle transition temperature before and after neutron irradiation in Reactor Pressure Vessel (RPV) steels produced by different manufacturing (refining) processes. The results were compared to the standard transition temperature shifts from the Charpy test and Master Curve fracture toughness test in accordance with the ASTM standard E1921. The samples were taken from 1/4t location of the vessel thickness and machined into a 10x10x0.5mm dimension. Irradiation of the samples was carried out in the research reactor at KAERI (HANARO) at about 290 .deg. C of the different fluence levels respectively. SP tests were performed in the temperature range of RT to -196 .deg. C using a 2.4mm diameter ball. For the materials before and after irradiation, SP transition temperatures (T{sub sp}), which are determined at the middle of the upper and lower SP energies, showed a linear correlation with the Charpy index temperature, T{sub 41J}. T{sub sp} from the irradiated samples was increased as the fluence level increased and was well within the deviation range of the unirradiated data. The TSP had a correlation with the reference temperature (T{sub 0}) from the master curve method using a pre-cracked Charpy V-notched (PCVN) specimen.

  1. Effect of Welding Speed and Tool Pin Geometry on Impact Strength in Friction Stir Welding of Aluminium 6101 T6 Alloy

    Directory of Open Access Journals (Sweden)

    Singh Rajbir

    2016-01-01

    Full Text Available Friction stir welding (FSW process is a solid state joining method in which the material that is being welded does not melt and recast. This process uses a non-consumable tool to generate frictional heat in the abutting surfaces. The welding parameters play a major role in deciding the joint characteristics. In this investigation the effect of welding speed and tool pin geometry in friction stir welds of Aluminium alloy was studied. The welded joints were made of Aluminium alloy AA 6101 T6 strips of 6mm thickness with different tool pin profile (Cylindrical, Taper cylindrical, Square and Taper Square. All the welding operations were done at the room temperature. Charpy tests were carried out to find the impact strength. From this investigation it is found that strength is superior with taper square tool pin profile than cylindrical, taper cylindrical and square tool pin profile. The pieces weld at rotational speed of 1200 r.p.m and welding speed of 70mm/min using taper square tool have higher strength.

  2. X60钢级HFW焊管焊缝冲击韧性异常原因分析%Cause Analysis on Abnormal Impact Toughness of X60 Steel HFW Pipe Weld

    Institute of Scientific and Technical Information of China (English)

    赵金兰; 雷俊杰; 王高峰; 聂向晖

    2014-01-01

    通过对某X60钢级HFW焊管进行拉伸试验、压扁试验及-20℃低温冲击试验,发现该焊管焊缝的冲击韧性异常低。采用金相显微分析、扫描电镜分析及能谱分析法对焊缝冲击韧性异常的原因进行了分析。结果表明,焊缝源区存在大量的灰斑,是造成焊缝冲击韧性较低的主要原因,母材组织中存在一定的带状组织也会降低焊缝的冲击韧性,另外,如果焊后热处理工艺不当,就不能起到改善焊缝冲击韧性的作用。%The tensile test, flattening test and -20 ℃ low temperature Charpy impact test on one X60 HFW pipe weld were carried out. It found that the impact toughness abnormal low. The cause of the low impact toughness was analyzed by the metallographic analysis, SEM and energy spectrum analysis. The results showed that, the existence of a large number of gray spot in weld source area is the main cause of low impact toughness, and the banded structure of base metal also can reduce the impact toughness of weld. In addition, improper heat treatment after welding will not improve weld impact toughness.

  3. MoSi2-Base Hybrid Composite Passed Engine Test

    Science.gov (United States)

    Keith, Theo G., Jr.; Hebsur, Mohan

    1998-01-01

    important property measured was impact resistance. Aircraft engine components require sufficient toughness to resist manufacturing defects, assembly damage, stress concentrations at notches, and foreign object damage. Engine company designers indicated that impact resistance would have to be measured before they would seriously consider these types of composites. The Charpy V-notch test was chosen to assess impact resistance, and both monolithic and composite versions Of MOSi2 were tested from -300 to 1400 C. The results (see the following graphs) show that nitride-particulate-reinforced MoSi2 exhibited impact resistance higher than that of many monolithic ceramics and intermetallics, and that the fiber-reinforced composites had even higher values, approaching that of cast superalloys.

  4. Introduction of a new dynamic fracture toughness evaluation system

    Science.gov (United States)

    Kobayashi, Toshiro; Yamamoto, Isamu; Niinomi, Mitsuo

    1993-05-01

    The instrumented Charpy impact test has been widely used as a simple method for semiempirically evaluating material impact toughness. The authors have developed a new instrumented Charpy impact testing system, which is called computer aided instrumented Charpy impact testing. Using this system, dynamic fracture toughness parameters and various absorbed energies can be obtained from the load-deflection curve of a single precracked specimen for both ductile and brittle materials. The system has been put into practical use in Japan. This paper introduces the details of the toughness evaluation procedures in the system.

  5. Irradiation programme MANITU. Results of impact tests with the irradiated materials of the second irradiation phase (0.8 dpa); Bestrahlungsprogramm MANITU. Ergebnisse der Kerbschlagbiegeversuche mit den bis 0,8 dpa bestrahlten Werkstoffen der zweiten Bestrahlungsphase

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, H.C.; Rieth, M.; Dafferner, B.; Ries, H.; Romer, O.

    2000-09-01

    The irradiation project MANITU was planned and carried out in the frame of the European Longterm Fusion Materials Development Programme. The problem of the irradiation induced embrittlement of possible martensitic alloy candidates is still unsolved. But after the evaluation of sub-size Charpy tests with the unirradiated reference specimens of MANITU a first tendency was recognizable. The mechanical properties of the newly developed low activation 7-10% Cr-W(Ge)VTa alloys are partly better compared to the modified commercial 10-11% Cr-NiMoVNb steels. After the evaluation of subsize Charpy tests with specimens irradiated up to 0.2 and 0.8 dpa in the first phase of the MANITU programme, better mechanical properties of the 7-10% Cr-W(Ge)VTa alloys were obvious. In the present report the results of instrumented impact tests within the second phase of the MANITU programme (irradiation dose 0.8 dpa, irradiation temperatures 250, 300, 350, 400, and 450 C) are analysed and assessed in comparison to the results of the irradiation up to 0.8 dpa in the first phase of the project. Among the examined alloys (OPTIMAR, OPTIFER-IV, GA3X) the GA3X steel shows the very best embrittlement behaviour after neutron irradiation. (orig.) [German] Das Bestrahlungsprojekt MANITU wurde im Rahmen des europaeischen Langzeitprogramms fuer Materialentwicklung fuer die Kernfusion geplant und durchgefuehrt. Das Problem der bestrahlungsinduzierten Versproedung bei den in Frage kommenden martensitischen Werkstoffen ist nach wie vor ungeloest. Eine erste Tendenz zeichnete sich jedoch nach der Auswertung der Kerbschlagbiegeversuche an den unbestrahlten miniaturisierten Referenzproben des MANITU-Programms ab. Die neu entwickelten niedrig aktivierbaren 7-10% Cr-W(Ge)VTa-Legierungen weisen gegenueber den modifizierten kommerziellen 10-11% Cr-NiMoVNb-Staehlen teilweise bessere mechanische Eigenschaften auf. Nach Auswertung der Kerbschlagbiegeversuche an den in der ersten Phase des MANITU-Programms mit 0

  6. Standard Guide for Predicting Radiation-Induced Transition Temperature Shift in Reactor Vessel Materials, E706 (IIF)

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 This guide presents a method for predicting reference transition temperature adjustments for irradiated light-water cooled power reactor pressure vessel materials based on Charpy V-notch 30-ftlbf (41-J) data. Radiation damage calculative procedures have been developed from a statistical analysis of an irradiated material database that was available as of May 2000. The embrittlement correlation used in this guide was developed using the following variables: copper and nickel contents, irradiation temperature, and neutron fluence. The form of the model was based on current understanding for two mechanisms of embrittlement: stable matrix damage (SMD) and copper-rich precipitation (CRP); saturation of copper effects (for different weld materials) was included. This guide is applicable for the following specific materials, copper, nickel, and phosphorus contents, range of irradiation temperature, and neutron fluence based on the overall database: 1.1.1 MaterialsA 533 Type B Class 1 and 2, A302 Grade B, A302 G...

  7. Analysis of fracture toughness in transition temperature region of a Mn-Mo-Ni low-alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Ho; Hwang, Byoung Chul; Lee, Sung Hak [Pohang Univ. of Science and Technology, Pohang (Korea, Republic of)

    2002-08-01

    This study is concerned with the analysis of fracture toughness in the transition region of a Mn-Mo-Ni low-alloy steel according to ASTM E1921 standard test method. Elastic-plastic cleavage fracture toughness, K{sub Jc} was determined by 3-point bend tests, using precracked Charpy V-notch (PCVN) specimens, and then the measured K{sub Jc} values were interpreted by the 3-parameter Weibull distribution with a theoretical slope of 4. fractographic observation indicated that the critical distance from a precrack tip to a cleavage initiation site linearly increased with increasing the critical J(J{sub c}) value, and that the stretch zone width had a good correlation with K{sub Jc} value, irrespective of testing temperature. Relationship between J{sub c} and critical distance, local fracture stress, and plane strain fracture toughness were discussed on the basis of the cleavage fracture behavior in the transition temperature region.

  8. Applicability of master curve concept for the safety assessment of power plant components - experimental investigations

    Energy Technology Data Exchange (ETDEWEB)

    Tanguy, B.; Stoeckl, H.; Siegele, D. [Fraunhofer-Institut fuer Werkstoffmechanik (IWM), Freiburg im Breisgau (Germany)

    2003-07-01

    This paper presents the application of the master curve concept to the determination of the reference temperature, T{sub 0} for two different reactor pressure vessel (RPV) steels. The aim of this study is to provide a wide experimental database and microstructural observations to study the applicability of master curve concept. Mechanical and fracture properties of 22NiMoCr3-7 and JRQ A533B steels have been investigated over a wide range of temperatures. Precracked Charpy V-notch (PCVN) and CT(1T) specimens were used to characterize the fracture toughness of two unirradiated reactor pressure vessel steels. The master curve methodology described in ASTM Standard E1921 was followed to determine the reference temperature, T{sub 0}. The reference temperature dependence on specimen geometry and on specimen location was evidenced. A systematic investigation of the nature and position of cleavage initiating sites has been carried out. (orig.)

  9. Current understanding of the effects of enviromental and irradiation variables on RPV embrittlement

    Energy Technology Data Exchange (ETDEWEB)

    Odette, G.R.; Lucas, G.E.; Wirth, B.; Liu, C.L. [Univ. of California, Santa Barbara, CA (United States)

    1997-02-01

    Radiation enhanced diffusion at RPV operating temperatures around 290{degrees}C leads to the formation of various ultrafine scale hardening phases, including copper-rich and copper-catalyzed manganese-nickel rich precipitates. In addition, defect cluster or cluster-solute complexes, manifesting a range of thermal stability, develop under irradiation. These features contribute directly to hardening which in turn is related to embrittlement, manifested as shifts in Charpy V-notch transition temperature. Models based on the thermodynamics, kinetics and micromechanics of the embrittlement processes have been developed; these are broadly consistent with experiment and rationalize the highly synergistic effects of most important irradiation (temperature, flux, fluence) and metallurgical (copper, nickel, manganese, phosphorous and heat treatment) variables on both irradiation hardening and recovery during post-irradiation annealing. A number of open questions remain which can be addressed with a hierarchy of new theoretical and experimental tools.

  10. Efecto de la Profundidad sobre la Soldabilidad de Aceros Ferríticos en Ambientes Simulados Unidos por Soldadura Húmeda

    Directory of Open Access Journals (Sweden)

    Fernando Macías López

    Full Text Available Resumen El objetivo de este trabajo fue evaluar el efecto de la profundidad sobre las propiedades en soldaduras de ranura en “V” con varios cordones de relleno. Metal base y electrodos comerciales fueron utilizados (ASTM A36 y AWS E7014 y cuatro diferentes condiciones se utilizaron para desarrollar las soldaduras húmedas como son 10, 20, 30 y 40m de profundidad. Una cámara presurizada con 30 atmósferas de capacidad fue utilizada para simular la profundidad, inundada con agua fresca. Un buzo soldador fue quien realizo las soldaduras. Las propiedades en la sección transversal mediante pruebas de tenacidad CVN (Charpy V-notch, macro ataque y esfuerzo a la tensión fueron determinadas por correlación. Las pruebas mecánicas con mejores resultados se observaron en la condición de 20m de profundidad.

  11. Mechanical and Microstructural Evaluation of DMAG Welding of Structural Steel

    Directory of Open Access Journals (Sweden)

    Tolga Mert

    2015-01-01

    Full Text Available Double channel torch, which allows concentric flow of two different shielding gases, was designed and manufactured in order to pursue double channel torch gas metal arc welding of unalloyed structural steel S235JR (EN 10025-2 with fourteen passes. Tensile and Charpy V-notch tests were realized and the results were compared with those of conventional gas metal arc welding. In order to evaluate mechanical testing results, microstructural analyses were conducted. It was found that the increase with double channel gas metal arc welding process in yield and tensile strengths as well as in toughness tests, especially in subzero temperatures, compared with conventional gas metal arc welding was due to longer columnar grains and finer tempered zone grain structure between passes and due to solidification and less dendritic structure formation in all-weld metal in double channel gas metal arc welding.

  12. Irradiation programme HFR phase 1b. Results of impact tests with the irradiated materials (2.4 dpa); Bestrahlungsprogramm HFR Phase 1b. Ergebnisse der Kerbschlagbiegeversuche mit den bis 2,4 dpa bestrahlten Werkstoffen

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, H.C.; Dafferner, B.; Ries, H.; Lautensack, S.; Romer, O.

    2004-04-01

    The irradiation project HFR phase 1b was planned and carried out in the frame of the European Long-term Fusion Materials Development Programme. It represents the continuation of the former High-Flux-Reactor irradiation programmes which are documented in detail in former FZK-reports. The problem of the irradiation induced embrittlement of possible martensitic alloy candidates is still not finally solved. After evaluation of sub-size Charpy tests with the 2.4 dpa irradiated specimens, the low activation 7-10%-Cr-W(Ge)VTa alloys showed outstandingly better characteristics compared to the modified commercial 10-11%-Cr-NiMoVNb steels. The emphasis of the phase 1b project is now on the investigation of low activating OPTIFER-alloys, which exhibit in contrast to the previously irradiated OPTIFER-steels a clearly reduced boron content in order to reduce the irradiation embrittlement. In the present report the results of instrumented impact tests within the phase 1b programme (irradiation dose 2.4 dpa, irradiation temperatures 250, 300, 350, 400, and 450 C) are analysed and assessed in comparison to the results of the MANITU- and HFR phase 1a- irradiation programmes. Herein, the OPTIFER-V steel, which is nearly identical to the industrial heat EUROFER97 (which became available after the irradiation), supplied the best results. (orig.)

  13. Evaluation of ductile-brittle transition temperature before and after neutron irradiation for RPV steels using small punch tests

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min-Chul [Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)]. E-mail: mckim@kaeri.re.kr; Oh, Yong Jun [Hanbat National University, Deogmyeong-dong, Yuseong-gu, Daejeon 305-719 (Korea, Republic of); Lee, Bong Sang [Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

    2005-08-01

    Small punch (SP) tests were performed to evaluate the ductile-brittle transition temperature before and after a neutron irradiation of reactor pressure vessel (RPV) steels produced by different manufacturing (refining) processes. The results were compared to the standard transition temperature shifts from the conventional Charpy tests and the Master Curve fracture toughness tests in accordance with the American Society for Testing and Materials (ASTM) standard E1921. Small punch specimens were taken from a 1/4t location of the vessel thickness and machined into a 10 mm x 10 mm x 0.5 mm dimension. The specimens were irradiated in the research reactors at Korea Atomic Energy Research Institute Nuclear Research Institute in the Czech Republic at the different fluence levels of about 290 deg C. Small punch tests were performed in the temperature range of RT to -196 deg C using a 2.4 mm diameter ball. For the materials before and after irradiation, the small punch transition temperatures (T {sub SP}), which are determined at the middle of the upper small punch energies, showed a linear correlation with the Charpy index temperature, T {sub 41J}. T {sub SP} from the irradiated samples was increased with the fluence levels and was well within the deviation range of the unirradiated data. However, the transition temperature shift from the Charpy test ({delta}T {sub 41J}) shows a better correlation with the transition temperature shift ({delta}T {sub SP(E)}) when a specific small punch energy level rather than the middle energy level of the small punch curve is used to determine the transition temperature. T {sub SP} also had a correlation with the reference temperature (T {sub 0}) from the Master Curve method using a pre-cracked Charpy V-notched (PCVN) specimen.

  14. Impact Behavior and Fracture Mechanism of Ductile Cast Iron with Minor Nickel Addition at Low Temperature%低镍球墨铸铁低温冲击性能及断裂机理研究

    Institute of Scientific and Technical Information of China (English)

    陈江; 黄兴民; 高杰维; 董海; 戴光泽

    2012-01-01

    使用激光共聚焦显微镜、扫描电镜和示波冲击等实验手段研究了镍元素(0.0%~0.9%,质量分数,下同)对球墨铸铁的微观组织和低温冲击性能的影响,对低温断裂机理进行了探讨.结果表明:含镍0.7%退火态球墨铸铁的韧脆转变温度低于-60℃,其-70℃下冲击功高于12J;适量镍元素添加能有效地细化晶粒和强化基体,改善球墨铸铁的低温冲击性能.%Utilizing laser confocal microscopy, SEM, instrumented impact and other experimental methods, the influence of nickel content(0. 0%-0. 9%,mass fraction, the same below) on the micro-structure and low temperature impact toughness of ductile cast iron(DCI) was investigated. The fracture mechanism of DCIs was studied further at different temperatures by using scanning electronic microscopy (SEM). The results show that ductile-to-brittle transition temperature of as-annealed DCIs with 0. 7% Ni content is lower than —60℃ , the impact energy of Charpy-type test is still higher than 12J at —70℃. Minor Ni addition of proper quantities might favor the grain refinement and matrix strengthen, low temperature impact toughness properties of DCIs are markedly improved.

  15. 芯壳结构竹塑复合材料断口冲击强度的分形表征%Fractal characterization of impact strength fracture of bamboo plastic composites with core-shell structure

    Institute of Scientific and Technical Information of China (English)

    羡瑜; 王翠翠; 王戈; 程海涛

    2015-01-01

    of different shell layer materials on the impact strength in the BPCs with core-shell structure, Charpy non-notched impact strength of the BPCs with core-shell structure was measured at room temperature according to ASTMD6110-2010. The fractographs of the BPCs with core-shell structure that had different shell layer materials were observed by scanning electron microscope (SEM). The impact fracture surface topography of BPCs manifested self-similarity. Based on fractal theory and computer image processing technology, a MATLAB program which computed the fracture’s box-counting dimension of the BPCs with core-shell structure was designed. The digital image was transformed into factual image, and the charpy impact fracture surface fractal dimensions of the BPCs with core-shell structure that had different shell layer materials were measured by pixel-covering method, to investigate the relationship between impact strength and fractal dimension of the BPCs with core-shell structure. Results showed that the BPCs fracture possessed fractal characteristics and there were differences for the fractal dimensions of the BPCs with core-shell structure that had different shell layer materials. The fractal dimensions of the fracture surface were within the range of from 2.2075 to 2.2204, the linear degree of fitted beeline of MATLAB program was high and the correlation coefficients obtained were more than 0.98. The strong linear correlation indicated that impact fracture surface of the BPCs with core-shell structure had significant fractal characteristics. The impact fracture topography of HDPE in the shell layer was the most complicated in 4 kinds of fractures of the BPCs with core-shell structure, and the fractal dimension was up to 2.2204; the impact fracture topography of white mud/HDPE in the shell layer was more regular, and the fractal dimension was the smallest. The results accorded with the observed results by human eyes. The impact strength of the BPCs with core

  16. 氢腐蚀分层对换热器筒体承载能力的影响%Influence of bearing capacity of heat exchanger shell caused by hydrogen corrosion delaminating crack

    Institute of Scientific and Technical Information of China (English)

    何家胜; 李超; 朱晓明; 陈伟; 路远明; 杨峰

    2013-01-01

    To explore the influence of hydrogen corrosion delaminating crack on the mechanical properties and bearing capacity in operation of the layered heat exchanger shell, the material capability of layered heat exchanger shell was analyzed by using chemical constituents analysis, hardness test, tensile tests, Charpy V-notch pendulum impact test. The finite element method was used to calculate the stress distribution of heat exchanger shell and to discuss the stress intensity factors of crack tip. The results show that the Mn element is lower in the chemical constituents, other elements accord with the National Standards; the material hardness meets the requirements, but the toughness declines obviously. The material of heat layered exchanger shell is deteriorated by the hydrogen corrosion, which destroys the continuity and uniformity of the material, decreases the ultimate strength, but increases the yield-strength ratio. The film stress state is destroyed, and material resistance to crack growth decreases. The hydrogen corrosion delaminating crack causes biggish partial stress and makes bearing capacity of the heat exchanger shell decrease.%为了解换热器筒体发生氢腐蚀分层后,其简体局部材料的性能发生的变化及对换热器运行中的承载能力带来的影响,采用化学成分分析、硬度测试、拉伸试验、夏比V口冲击韧性试验等方法对换热器筒体材料的性能进行了分析;运用有限元分析方法计算了简体分层处的应力分布,并探讨了裂纹尖端应力强度因子的变化情况.研究结果表明:材料化学成分中除Mn元素的含量偏低外,其它元素含量符合国家标准;材料的硬度符合要求,材料的强度极限降低,屈强比上升,韧性明显降低.氢腐蚀分层使换热器筒体材料局部劣化,破坏了材料的均匀性和连续性,破坏了简体的薄膜应力状态,产生了较大的局部应力,使换热器筒体承载能力下降.

  17. Felled trees as a rockfall protection system: Impact on simply supported fresh wood stems, experimental and numerical study

    Science.gov (United States)

    Olmedo, Ignacio; Bourrier, Franck; Bertrand, David; Berger, Frédéric; Limam, Ali

    2014-05-01

    Forest is a well known and efficient natural protection solution against rockfall. In forested areas, the maintenance of forests is required to ensure their protective function and health. During this process that consists in removing some trees, the protective capacity of the forest decreases. To compensate the temporary loss of protection, some of the felled trees can be left in an oblique position to the slope. It is a financially feasible solution to ensure the protection against rockfall during the regeneration of forests. Thus, felled trees can become a useful protection system if they are correctly placed. No studies have been done concerning the efficiency of these devices and particularly their resistance to rock impacts and their energy dissipation capacity. In order to estimate the capacity of these devices to dissipate energy, it is necessary to study the dynamic response of tree stems under impact as well as rock's trajectory changes due the interaction with such structures. Experimental and numerical studies are carried out to determine the efficacy of this devices. Laboratory experiments enabled studying the response of fresh wood stems under dynamic and quasi-static loadings. A Mouton-Charpy pendulum was used on the dynamic loading tests performed onto simply supported stems. The experimental device was instrumented in order to obtain the impact force data and the stem's displacements fields. The mechanical properties of fresh wood are analyzed from the experimental results which also allow carrying out a detailed study of the stems dynamic response. A numerical model based on the Discrete Element Method (DEM) enables to simulate the interaction of a rock and a felled tree device. To simulate the rock - tree interactions, rocks are represented by spherical solid bodies while cylindrical bodies represent the trees. The fresh wood constitutive law and the contact law are integrated on the model allowing realistic simulations. The numerical model is

  18. 3D analyses of the effect of weld orientation in Charpy specimens

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, A.

    2004-01-01

    of failure in the weld material, base material and heat affected zone (HAZ). For these rotated specimens the location where the notch crosses the thin layer of HAZ, i.e. whether this location is near the center of the specimen or near the free specimen edge, makes a large difference in the response. (C) 2004...

  19. Dynamic finite element analysis of third size charpy specimens of V-4Cr-4Ti

    Energy Technology Data Exchange (ETDEWEB)

    Lansberry, M.R.; Kumar, A.S.; Mueller, G.E. [Univ. of Missouri, Rolla, MO (United States); Kurtz, R.J. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-04-01

    A 2-D finite element analysis was performed on precracked, one third scale CVN specimens to investigate the sensitivity of model results to key material parameters such as yield strength, failure strain and work hardening characteristics. Calculations were carried out at temperatures of -196{degree}C and 50{degree}C. The dynamic finite element analyses were conducted using ABAQUS/Explicit V5.4. The finite element results were compared to experimental results for the production-scale heat of V-4Cr-4Ti (ANL Heat No. 832665) as a benchmark. Agreement between the finite element model and experimental data was very good at -196{degree}C, whereas at 50{degree}C the model predicted a slightly lower absorbed energy than actually measured.

  20. Assessment of J-R Curves Obtained from Precracked Charpy Samples

    Science.gov (United States)

    1985-09-01

    16 3. J-R curves for A723, Class 1, Grade 4 pressure vessel steel . 17 4. J-R curves for HY80 steel . 18 5. J-R curves for HY130 steel . 19 DTIC t,. 1 NV...In HY80 and KY130 steels , it is clear that significant strain-hardening occurred. The effect of strain-hardening could be crack growth at peak load...aimmoSO ff nwoa MW Identify b black nrnmsbm’) 3-R curves were determined for five materials (7075-T651; 2024-T351; HY13O; HY80 ; and A723, Class 1

  1. The Chicxulub Impact Crater and Oblique Impact

    Science.gov (United States)

    McDonald, M.; Gulick, S.; Melosh, H.; Christeson, G.

    2007-05-01

    Determining whether or not the Chicxulub impact was oblique (<45 degrees) will aid in our understanding of the environmental consequences 65 Ma. Planetary impact events, and impact simulations in the laboratory, show that oblique impacts have clear asymmetric ejecta distributions. However, the subsurface structures of the resultant craters are not well understood. In 2005, we acquired 1822 km of seismic reflection data onboard the R/V Maurice Ewing imaging the massive (200+ km) Chicxulub impact crater. The seismic profiles show that pre- crater stratigraphy outside the central basin of the Chicxulub impact crater is offset downward into the crater marking the post-impact slumping and formation of the terrace zone. The inward collapse of the Chicxulub terrace zone coincides with the outward collapse of the central uplift to form the peak ring. Chicxulub's peak ring is offset to the southeast, away from the deepest terrace zone mapped in the seismic data, suggesting that its peak ring was offset toward a more gradual wall of the transient cavity. Peak ring offsets, relative to crater center, of Venusian craters from radar images in the Magellan data set allow us to determine whether there are systematic variations in peak ring offset due to oblique impact. Ten pristine Venusian peak ring craters formed by oblique impact show that peak rings are offset both uprange and downrange, suggesting that peak ring position, and related subsurface asymmetries in the terrace zone, do not provide information about impact obliquity. This analysis supports the idea that Chicxulub's peak ring offset is a consequence of target properties and pre-impact structure and independent of impact trajectory.

  2. How is impact factor impacting our research?

    Science.gov (United States)

    Rawat, Seema

    2014-01-01

    The impact factor (IF) of an journal is a measure reflecting the average number of citations to recent articles published in the journal. It is frequently used as a proxy for the relative importance of a journal within its field, with journals with higher impact factors deemed to be more important than those with lower ones. However it is not a perfect metric and has its own limitations. Journals are increasingly finding new ways to improve their impact factor by increasing self citation, publishing more review articles. This correspondence discuss the fallacies of the impact factor.

  3. Impactitis: The impact factor myth syndrome

    Directory of Open Access Journals (Sweden)

    Elsaie Mohamed

    2009-01-01

    Full Text Available Background : In the early 1960s, Eugene Garfield and Irving Sher created the journal impact factor to help select journals for the Science Citation Index (SCI. Today it has become a widespread subject of controversy even for Garfield, the man who created it who is quoted saying " Impact Factor is not a perfect tool to measure the quality of articles but there is nothing better and it has the advantage of already being in existence and is, therefore, a good technique for scientific evaluation". The use of the term "impact factor" has gradually evolved, especially in Europe, to include both journal and author impact. This ambiguity often causes problems. It is one thing to use impact factors to compare journals and quite another to use them to compare authors. Journal impact factors generally involve relatively large populations of articles and citations. Individual authors, on average, produce much smaller numbers of articles. Objectives: Impact factor, an index based on the frequency with which a journal′s articles are cited in scientific publications, is a putative marker of journal quality. However, empiric studies on impact factor′s validity as an indicator of quality are lacking. The authors try to evaluate and highlight the validity of Impact Factors and its significance as a tool of assessment for scientific publications. Methods: Analysis of the several reports in literature and from their own point of view. Conclusion: A journal′s impact factor is based on 2 elements: the numerator, which is the number of citations in the current year to any items published in a journal in the previous 2 years, and the denominator, which is the number of substantive articles (source items published in the same 2 years. The impact factor could just as easily be based on the previous year′s articles alone, which would give an even greater weight to rapidly changing fields.

  4. Effect of lead factors on the embrittlement of RPV SA-508 cl 3 steel

    Energy Technology Data Exchange (ETDEWEB)

    Kempf, Rodolfo, E-mail: kempf@cnea.gov.ar [CNEA, Unidad Actividad Combustibles Nucleares, División Caracterización, Avda. Gral Paz 1499, C.P.B1650KNA, San Martín, Buenos Aires (Argentina); Troiani, Horacio, E-mail: troiani@cab.cnea.gov.ar [Centro Atómico Bariloche (CNEA) e Instituto Balseiro (UNCU), CONICET, Av. Bustillo 9500, CP 8400, Rio Negro (Argentina); Fortis, Ana Maria, E-mail: fortis@cnea.gov.ar [CNEA, Departamento Estructura y Comportamiento, UNSAM, Avda. Gral Paz 1499, C.P.B1650KNA, San Martín, Buenos Aires (Argentina)

    2013-03-15

    This paper presents a project to study the effect of lead factors on the mechanical behaviour of the SA-508 type 3 Reactor Pressure Vessel (RPV) steel used in the reactor under construction Atucha II in Argentina. Charpy-V notch specimens of this steel were irradiated at the RA1 experimental reactor at a temperature of 275 °C with two lead factors (186 and 93). The neutron flux was 3.71 × 10{sup 15} n m{sup −2} s{sup −1} and 1.85 × 10{sup 15} n m{sup −2} s{sup −1} (E > 1 MeV) respectively. In both cases, the fluence was 6.6 × 10{sup 21} n m{sup −2}, which is equivalent to that received by the PHWR Atucha II RPV in 10 years of full power irradiation. The results of Charpy tests revealed significant embrittlement both in the ΔT = 14 °C and ΔT = 21 °C shifts of the ductile–brittle transition temperatures (DBTT) and in the reduction of the maximum energy absorbed. This result shows that the shift of the DBTT with a lead factor of 93 is larger than that obtained with a lead factor of 186. Then, the results of irradiation in experimental reactors (MTR) with high lead factors may not be conservative with respect to the actual RPV embrittlement.

  5. Chicxulub Ejecta Impact Trenches And Terminal Impact

    Science.gov (United States)

    Page, R. L.

    2013-05-01

    DISCOVERY During a Pacific voyage from E. Australia to the US on a small sailing research vessel what appears to be two Chicxulub impact trenches were discovered in the ocean floor at depths of 4,627m and 3,519m. DESCRIPTION Trench A begins at a depth of 4,627m, 704km from the Chicxulub impact and is 18km long, 5km wide and 225m deep. Trench B begins at a depth of 3,519m, 732km from the Chixculub impact and is 23km long, 7 km wide and 400m deep. At the end of Trench B is what appears to be a debris deposit 5km long. Their relationship to the Chicxulub impact seems confirmed by their central axis, which when extended intersect at the Chicxulub impact at N Lat 21.33, W Long 89.5. Down range 286km from the end of Trench B is what appears to be the terminal impact of the object that created the two trenches. This is in the form of several large boulders, small seamounts, and islands in shallower depths indicating breakup of the object 1040km from the Chicxulub impact. The trenches are in an area of the Caribbean where currents prevented them from being silted in, preserving their physical form on the ocean floor. The object that created the trenches could have been large ejecta from the impact or possibly part of the asteroid that separated before impact or upon impact and carried on 1000km down range. The trajectory of both trenches is an upward angle of about 3 degrees. This indicates that the trajectory of the object was at a low angle, very high velocity and was deflected slightly upward upon impact with the ocean floor 4,627 below sea level. RESEARCH The first two phases of 10 phases consisting of mapping, exploration, research, and documentation of the impacts have been completed. Phase 1 consisted of assembling available sea floor data of the area of the impacts. Phase 2 consisted of selecting aerial and under water images from Google Earth, preparing bathymetric mapping from a GEBCO_08. BODC raster analysis with 50m contour intervals of the impact area

  6. Impacted science: impact is not importance.

    Science.gov (United States)

    Casadevall, Arturo; Fang, Ferric C

    2015-10-13

    The journal impact factor (IF) exerts a tremendous influence on the conduct of scientists. The obsession with IF has been compared to a medical condition, sometimes referred to as "IF mania" or "impactitis." Here, we analyze the difference between impact and importance, using examples from the history of science to show that these are not equivalent. If impact does not necessarily equal importance, but scientists are focused on high-impact work, there is a danger that misuse of the IF may adversely affect scientific progress. We suggest five measures to fight this malady: (i) diversify journal club selections, (ii) do not judge science on the publication venue, (iii) reduce the reliance on journal citation metrics for employment and advancement, (iv) discuss the misuse of the IF in ethics courses, and (v) cite the most appropriate sources. If IF mania is indeed a medical condition, the most appropriate course of action may be disimpaction.

  7. Vibro-impact dynamics

    CERN Document Server

    Luo, Albert C J

    2012-01-01

    Presents a systematic view of vibro-impact dynamics based on the nonlinear dynamics analysis Comprehensive understanding of any vibro-impact system is critically impeded by the lack of analytical tools viable for properly characterizing grazing bifurcation. The authors establish vibro-impact dynamics as a subset of the theory of discontinuous systems, thus enabling all vibro-impact systems to be explored and characterized for applications.  Vibro-impact Dynamics presents an original theoretical way of analyzing the behavior of vibro-impact dynamics that can be extended to discontinuous dynamic

  8. Microstructure and Impact Toughness Resistance of TC4 Titanium Alloy%TC4钛合金的显微组织及其抗冲击韧性

    Institute of Scientific and Technical Information of China (English)

    刘建强

    2013-01-01

    对TC4钛合金采用不同的热处理工艺,获得了马氏体组织、粗大网篮组织、针状组织、魏氏组织、蠕虫状组织和等轴状+块状双态组织的组织状态,采用夏比冲击试验,对其抗冲击韧性进行分析.结果表明:不同组织状态的TC4钛合金,其抗冲击韧性存在较大差异,原始态TC4钛合金为粗大的魏氏组织,抗冲击韧性很差,Akv2可达20 J;热处理后,等轴状+块状双态组织的冲击功最高,Akv2可达60 J,抗冲击韧性较好;马氏体组织、针状组织、粗大篮网状组织和魏氏组织的冲击功较低,Akv2可达40J,抗冲击韧性较差;蠕虫状组织冲击功最低,Akv2约为30 J,抗冲击韧性最差.%TC4 titanium alloy was treated by different technics of heat treatment.The microstructure stater of martensite,basketweave,acicular,widmanstatten and vermicular were obtained.The toughness of resistance impact was analyzed by Charpy impact test.The results show that the toughness of resistance impact of TC4 alloy is different.The microstructure of original TC4 alloy is widmanstatten,which the resistance impact toughness is bad,that Akv2 is about 20 J.After heat treatment,the toughness impact of duplex microstructure of equal axis shape and block is better,that Akv2 is about 60 J.The resistance impact toughness is martensite,needle,basketry and widmanstatten,that Akv2 is about 40 J,the resistance impact toughness of the microstructure of vermicular is worst,that Akv2 is about 30 J.

  9. Irradiation programme MANITU. Results of impact tests with the irradiated materials of the first irradiation phase (0.8 dpa); Bestrahlungsprogramm MANITU. Ergebnisse der Kerbschlagbiegeversuche mit den bis 0,8 dpa bestrahlten Werkstoffen der ersten Bestrahlungsphase

    Energy Technology Data Exchange (ETDEWEB)

    Rieth, M.; Dafferner, B.; Ries, H.; Romer, O.

    1995-09-01

    The irradiation project MANITU was planned and carried out in the frame of the European Longterm Fusion Materials Development Programme. The problem of the irradiation induced embrittlement of possible martensitic alloy candidates is still unsolved. But after the evaluation of subsize Charpy tests with the unirradiated reference specimens of MANITU a first tendency was recognizable. The mechanical properties of the newly developed low activation 7-10% Cr-W(Ge)VTa alloys are partly better compared to the modified commercial 10-11% Cr-NiMoVNb steels. In the present report the results of instrumented impact tests within the first phase of the MANITU programme (irradiation dose 0.8 dpa, irradiation temperatures 250, 300, 350, 400, and 450 C) are analysed and assessed. Among all examined alloys (MANET-I, MANET-II, K-heat, OPTIFER-Ia, OPTIFER-II, F82H, 9Cr-2WVTa ORNL 3791) the ORNL steel shows the very best embrittlement behaviour after neutron irradiation. (orig.) [Deutsch] Das Bestrahlungsprojekt MANITU wurde im Rahmen des europaeischen Langzeitprogramms fuer Materialentwicklung fuer die Kernfusion geplant und durchgefuehrt. Das Problem der bestrahlungsinduzierten Versproedung bei den in Frage kommenden martensitischen Werkstoffen ist nach wie vor ungeloest. Eine erste Tendenz zeichnete sich jedoch nach der Auswertung der Kerbschlagbiegeversuche an den unbestrahlten miniaturisierten Referenzproben des MANITU-Programms ab. Die neu entwickelten niedrig aktivierbaren 7-10% Cr-W(Ge)VTa-Legierungen weisen gegenueber den modifizierten kommerziellen 10-11% Cr-NiMoVNb-Staehlen teilweise bessere mechanische Eigenschaften auf. Im vorliegenden Bericht werden die Ergebnisse aus den instrumentierten Kerbschlagbiegeversuchen der ersten Phase des MANITU-Programms (Bestrahlungsdosis 0,8 dpa, Bestrahlungstemperaturen 250, 300, 350, 400 und 450 C) analysiert und bewertet. Von den untersuchten Legierungen (MANET-I, MANET-II, Kastencharge, OPTIFER-Ia, OPTIFER-II, F82H, 9Cr-2WVTa ORNL 3791

  10. Irradiation programme MANITU. Results of impact tests with the irradiated materials (0.2 dpa); Bestrahlungsprogramm MANITU. Ergebnisse der Kerbschlagbiegeversuche mit den bis 0,2 dpa bestrahlten Werkstoffen

    Energy Technology Data Exchange (ETDEWEB)

    Rieth, M.; Dafferner, B.; Kunisch, W.; Ries, H.; Romer, O.

    1997-04-01

    The irradiation project MANITU was planned and carried out in the frame of the European Longterm Fusion Materials Development Programme. The problem of the irradiation induced embrittlement of possible martensitic alloy candidates is still unsolved. But after the evaluation of subsize Charpy tests with specimens of MANITU (0.8 dpa) a first tendency was recognizable. The mechanical properties of the newly developed low activation 7-10% Cr-W(Ge)VTa alloys are better compared to the modified commercial 10-11% Cr-NiMoVNb steels. In the present report the results of instrumented impact tests of the MANITU programme (irradiation dose 0.2 dpa, irradiation temperatures 250, 300, 350, 400, and 450 C) are analysed and assessed. Among all examined alloys (MANET-I, MANET-II, K-heat, OPTIFER-Ia, OPTIFER-II, F82H, 9Cr-2WVTa ORNL 3791) the ORNL steel shows the best embrittlement behaviour after neutron irradation. (orig.) [Deutsch] Das Bestrahlungsprojekt MANITU wurde im Rahmen des europaeischen Langzeitprogramms fuer Materialentwicklung fuer die Kernfusion geplant und durchgefuehrt. Das Problem der bestrahlungsinduzierten Versproedung bei den in Frage kommenden martensitischen Werkstoffen ist nach wie vor ungeloest. Eine erste Tendenz zeichnete sich jedoch nach der Auswertung der Kerbschlagbiegeversuche an den bis 0,8 dpa bestrahlten miniaturisierten Proben des MANITU-Programms ab. Die neu entwickelten niedrig aktivierbaren 7-10% Cr-W(Ge)VTa-Legierungen weisen gegenueber den modifizierten kommerziellen 10-11% Cr-NiMoVNb-Staehlen bessere mechanische Eigenschaften auf. Im vorliegenden Bericht werden die Ergebnisse aus den instrumentierten Kerbschlagbiegeversuchen des MANITU-Programms (Bestrahlungsdosis 0,2 dpa, Bestrahlungstemperaturen 250, 300, 350, 400 und 450 C) analysiert und bewertet. Von den untersuchten Legierungen (MANET-I, MANET-II, Kastencharge, OPTIFER-Ia, OPTIFER-II, F82H, 9Cr-2WVTa ORNL 3791) zeigt der ORNL-Stahl das beste Versproedungsverhalten nach

  11. Head Impact Laboratory (HIL)

    Data.gov (United States)

    Federal Laboratory Consortium — The HIL uses testing devices to evaluate vehicle interior energy attenuating (EA) technologies for mitigating head injuries resulting from head impacts during mine/...

  12. Deep Impact Spots Quarry

    Science.gov (United States)

    2005-01-01

    Sixty-nine days before it gets up-close-and-personal with a comet, NASA's Deep Impact spacecraft successfully photographed its quarry, comet Tempel 1, at a distance of 39.7 million miles. The image, taken on April 25, 2005, is the first of many comet portraits Deep Impact will take leading up to its historic comet encounter on July 4.

  13. Impact assessment revisited

    DEFF Research Database (Denmark)

    Thiele, Jan; Kollmann, Johannes Christian; Markussen, Bo

    2010-01-01

    The theoretical underpinnings of the assessment of invasive alien species impacts need to be improved. At present most approaches are unreliable to quantify impact at regional scales and do not allow for comparison of different invasive species. There are four basic problems that need to be addre......The theoretical underpinnings of the assessment of invasive alien species impacts need to be improved. At present most approaches are unreliable to quantify impact at regional scales and do not allow for comparison of different invasive species. There are four basic problems that need...... to be addressed: (1) Some impacted ecosystem traits are spatially not additive; (2) invader effects may increase non-linearly with abundance or there may be effect thresholds impairing estimates of linear impact models; (3) the abundance and impact of alien species will often co-vary with environmental variation......; and (4) the total invaded range is an inappropriate measure for quantifying regional impact because the habitat area available for invasion can vary markedly among invasive species. Mathematical models and empirical data using an invasive alien plant species (Heracleum mantegazzianum) indicate...

  14. Asteroid Impact Monitoring

    Science.gov (United States)

    Milani, A.

    2006-06-01

    Some asteroids and comets with Earth-crossing orbit may impact our planet, thus we need to be able to identify the cases which could have a dangerous close approach within a century. This must be done as soon as such an asteroid is discovered, allowing for follow up observations which might contradict the impact possibility, and in the worst case to organize mitigation, possibly including deflection. The mathematical problem of predicting possible impacts, even with very low probabilities, has been solved by our group in the last few years. This paper presents the basic theory of these impact prediction, and discusses how they are practically used in the impact monitoring systems now operational, in particular the CLOMON2 robot of the Universities of Pisa and Valladolid.

  15. Asteroid impact monitoring

    Directory of Open Access Journals (Sweden)

    Milani A.

    2006-01-01

    Full Text Available Some asteroids and comets with Earth-crossing orbit may impact our planet, thus we need to be able to identify the cases which could have a dangerous close approach within a century. This must be done as soon as such an asteroid is discovered, allowing for follow up observations which might contradict the impact possibility, and in the worst case to organize mitigation, possibly including deflection. The mathematical problem of predicting possible impacts, even with very low probabilities, has been solved by our group in the last few years. This paper presents the basic theory of these impact prediction, and discusses how they are practically used in the impact monitoring systems now operational, in particular the CLOMON2 robot of the Universities of Pisa and Valladolid.

  16. Integrated impact assessment

    Energy Technology Data Exchange (ETDEWEB)

    Porter, A.L.; Rossini, F.A.

    1981-12-01

    Impact assessment studies the effects on society of proposed projects, programs, or policies. It is perhaps best known in the forms of technology assessment and environmental-impact assessment. The institutionalization of impact assessment, the principal features of impact assessment and its performance are discussed here, keynoting interdisciplinarity as a critical factor. Substantial progress in performance has occurred over the past decade, especially in environmental and social analyses, pointing to some critical issues for the decade ahead. Within studies, integration across disciplinary components, between contributions from professionals and parties-at-interest, and between producers and users must be improved. Across studies, practitioners of impact assessment need to intercommunicate to advance the state of their art. 38 references.

  17. Effect of iron-intermetallics and porosity on tensile and impact properties of aluminum-silicon-copper and aluminum-silicon-magnesium cast alloys

    Science.gov (United States)

    Ma, Zheyuan

    Aluminum-silicon (Al-Si) alloys are an important class of materials that constitute the majority of aluminum cast parts produced, due to their superior properties and excellent casting characteristics. Within this family of alloys, Al-Si-Cu and Al-Si-Mg cast alloys are frequently employed in automotive applications. The commercially popular 319 and 356 alloys, representing these two alloy systems, were selected for study in the present work, with the aim of investigating the effect of iron intermetallics and porosity on the alloy performance. This was carried out through a study of the tensile and impact properties, these being two of the important mechanical properties used in design calculations. Iron, through the precipitation of second phase intermetallic constituents, in particular the platelike beta-Al5FeSi phase, is harmful to the alloy properties. Likewise, gas- or shrinkage porosity in castings is also detrimental to the mechanical properties. By determining the optimum alloying, melt processing and solidification parameters (viz., Fe content, Sr modification and cooling rate) required to minimize the harmful effects of porosity and iron intermetallics, and studying their role on the fracture behavior, the fracture mechanism in the alloys could be determined. Castings were prepared from both industrial and experimental 319.2, B319.2 and A356.2 alloy melts, containing Fe levels of 0.2--1.0 wt%. Sr-modified (˜200 ppm) melts were also prepared for each alloy Fe level. The end-chilled refractory mold used provided directional solidification and a range of cooling rates (or dendrite arm spacings, DAS) within the same casting. Tensile and impact test samples machined from specimen blanks sectioned from the castings at various heights above the chill end provided DASs of 23--85mum. All samples were T6-heat-treated before testing. Tests were carried out employing Instron Universal and Instrumented Charpy testing machines. Optical microscopy, image analysis, SEM

  18. Emotional impact of halitosis

    Directory of Open Access Journals (Sweden)

    Bernard Troger

    2014-12-01

    Full Text Available OBJECTIVE: To evaluate the emotional impact of halitosis on 18-year-old men using a self-reported questionnaire.METHOD:A total of 2,224 participants underwent dental and medical examinations in the army medical services in the city of Pelotas, southern Brazil, in July 2008.RESULTS: In this sample, 12% of respondents expressed concern about their oral malodor, which had a strong emotional impact on their quality of life.CONCLUSIONS: The individuals reporting halitosis showed a higher degree of concern with their oral malodor. Low educational level and low income were associated with psychological impact and halitosis in this population.

  19. Writing for Impact

    DEFF Research Database (Denmark)

    Meier, Ninna

    2016-01-01

    Academic work may have impact in a variety of ways, depending on purpose, audience and field, but this is most likely to happen when your work resonates in meaningful ways with people. Ninna Meier encourages a more systematic investigation of the role of writing in achieving impact. Impact through...... writing means getting your readers to understand and remember your message and leave the reading experience changed. The challenge is to make what you write resonate with an audience’s reservoir of experiential knowledge. If the words do not connect to anything tangible, interest can be quickly lost....

  20. Impact of granular drops

    KAUST Repository

    Marston, J. O.

    2013-07-15

    We investigate the spreading and splashing of granular drops during impact with a solid target. The granular drops are formed from roughly spherical balls of sand mixed with water, which is used as a binder to hold the ball together during free-fall. We measure the instantaneous spread diameter for different impact speeds and find that the normalized spread diameter d/D grows as (tV/D)1/2. The speeds of the grains ejected during the “splash” are measured and they rarely exceed twice that of the impact speed.

  1. Environmental impact report (draft)

    Energy Technology Data Exchange (ETDEWEB)

    1980-05-01

    The three projects as proposed by Pacific Gas and Electric Company and the environmental analysis of the projects are discussed. Sections on the natural and social environments of the proposed projects and their surrounding areas consist of descriptions of the setting, discussions of the adverse and beneficial consequences of the project, and potential mitigation measures to reduce the effects of adverse impacts. The Environmental Impact Report includes discussions of unavoidable adverse effects, irreversible changes, long-term and cumulative impacts, growth-inducing effects, and feasible alternatives to the project. (MHR)

  2. 78 FR 13082 - Draft Environmental Impact Report/Environmental Impact Statement/Environmental Impact Statement...

    Science.gov (United States)

    2013-02-26

    ... Bureau of Reclamation Draft Environmental Impact Report/Environmental Impact Statement/ Environmental...: The Bureau of Reclamation has made available for public review and comment the draft Environmental Impact Report/Environmental Impact Statement/Environmental Impact Statement (EIR/EIS/EIS) for the...

  3. Impact Management System

    Data.gov (United States)

    US Agency for International Development — IMS (developed w/Iraq mission) is a system for conducting quality portfolio impact analysis, linking projects to strategy through integration of context data. IMS...

  4. Quality Measurement Impact Reports

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Secretary of the Department of Health and Human Services is required to assess the impact of consensus-endorsed quality and efficiency measures used in federal...

  5. Weather Radar Impact Zones

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent an inventory of the national impacts of wind turbine interference with NEXRAD radar stations. This inventory was developed by the NOAA Radar...

  6. Economic impacts study

    Energy Technology Data Exchange (ETDEWEB)

    Brunsen, W.; Worley, W.; Frost, E.

    1988-09-30

    This is a progress report on the first phase of a project to measure the economic impacts of a rapidly changing U.S. target base. The purpose of the first phase is to designate and test the macroeconomic impact analysis model. Criteria were established for a decision-support model. Additional criteria were defined for an interactive macroeconomic impact analysis model. After a review of several models, the Economic Impact Forecast System model of the U.S. Army Construction Research Laboratory was selected as the appropriate input-output tool that can address local and regional economic analysis. The model was applied to five test cases to demonstrate its utility and define possible revisions to meet project criteria. A plan for EIFS access was defined at three levels. Objectives and tasks for scenario refinement are proposed.

  7. Citing for High Impact

    CERN Document Server

    Shi, Xiaolin; McFarland, Daniel A

    2010-01-01

    The question of citation behavior has always intrigued scientists from various disciplines. While general citation patterns have been widely studied in the literature we develop the notion of citation projection graphs by investigating the citations among the publications that a given paper cites. We investigate how patterns of citations vary between various scientific disciplines and how such patterns reflect the scientific impact of the paper. We find that idiosyncratic citation patterns are characteristic for low impact papers; while narrow, discipline-focused citation patterns are common for medium impact papers. Our results show that crossing-community, or bridging citation patters are high risk and high reward since such patterns are characteristic for both low and high impact papers. Last, we observe that recently citation networks are trending toward more bridging and interdisciplinary forms.

  8. Earthquake impact scale

    Science.gov (United States)

    Wald, D.J.; Jaiswal, K.S.; Marano, K.D.; Bausch, D.

    2011-01-01

    With the advent of the USGS prompt assessment of global earthquakes for response (PAGER) system, which rapidly assesses earthquake impacts, U.S. and international earthquake responders are reconsidering their automatic alert and activation levels and response procedures. To help facilitate rapid and appropriate earthquake response, an Earthquake Impact Scale (EIS) is proposed on the basis of two complementary criteria. On the basis of the estimated cost of damage, one is most suitable for domestic events; the other, on the basis of estimated ranges of fatalities, is generally more appropriate for global events, particularly in developing countries. Simple thresholds, derived from the systematic analysis of past earthquake impact and associated response levels, are quite effective in communicating predicted impact and response needed after an event through alerts of green (little or no impact), yellow (regional impact and response), orange (national-scale impact and response), and red (international response). Corresponding fatality thresholds for yellow, orange, and red alert levels are 1, 100, and 1,000, respectively. For damage impact, yellow, orange, and red thresholds are triggered by estimated losses reaching $1M, $100M, and $1B, respectively. The rationale for a dual approach to earthquake alerting stems from the recognition that relatively high fatalities, injuries, and homelessness predominate in countries in which local building practices typically lend themselves to high collapse and casualty rates, and these impacts lend to prioritization for international response. In contrast, financial and overall societal impacts often trigger the level of response in regions or countries in which prevalent earthquake resistant construction practices greatly reduce building collapse and resulting fatalities. Any newly devised alert, whether economic- or casualty-based, should be intuitive and consistent with established lexicons and procedures. Useful alerts should

  9. Impact on floating membranes

    OpenAIRE

    Vandenberghe, Nicolas; Duchemin, Laurent

    2016-01-01

    When impacted by a rigid object, a thin elastic membrane with negligible bending rigidity floating on a liquid pool deforms. Two axisymmetric waves radiating from the impact point propagate. In the first place, a longitudinal wave front -- associated with in-plane deformation of the membrane and traveling at constant speed -- separates an outward stress free domain with a stretched but flat domain. Then, in the stretched domain a dispersive transverse wave travels at a wave speed that depends...

  10. Applied Impact Physics Research

    Science.gov (United States)

    Wickert, Matthias

    2013-06-01

    Applied impact physics research is based on the capability to examine impact processes for a wide range of impact conditions with respect to velocity as well as mass and shape of the projectile. For this reason, Fraunhofer EMI operates a large variety of launchers that address velocities up to ordnance velocities as single stage powder gun but which can also be operated as two-stage light gas guns achieving the regime of low earth orbital velocity. Thereby for projectile masses of up to 100 g hypervelocity impact phenomena up to 7.8 km/s can be addressed. Advanced optical diagnostic techniques like microsecond video are used as commercial systems but - since impact phenomena are mostly related with debris or dust - specialized diagnostics are developed in-house like x-ray cinematography and x-ray tomography. Selected topics of the field of applied impact physics will be presented like the interesting behavior of long rods penetrating low-density materials or experimental findings at hypervelocity for this class of materials as well as new x-ray diagnositic techniques.

  11. Experimental impact crater morphology

    Science.gov (United States)

    Dufresne, A.; Poelchau, M. H.; Hoerth, T.; Schaefer, F.; Thoma, K.; Deutsch, A.; Kenkmann, T.

    2012-04-01

    The research group MEMIN (Multidisciplinary Experimental and Impact Modelling Research Network) is conducting impact experiments into porous sandstones, examining, among other parameters, the influence of target pore-space saturation with water, and projectile velocity, density and mass, on the cratering process. The high-velocity (2.5-7.8 km/s) impact experiments were carried out at the two-stage light-gas gun facilities of the Fraunhofer Institute EMI (Germany) using steel, iron meteorite (Campo del Cielo IAB), and aluminium projectiles with Seeberg Sandstone as targets. The primary objectives of this study within MEMIN are to provide detailed morphometric data of the experimental craters, and to identify trends and characteristics specific to a given impact parameter. Generally, all craters, regardless of impact conditions, have an inner depression within a highly fragile, white-coloured centre, an outer spallation (i.e. tensile failure) zone, and areas of arrested spallation (i.e. spall fragments that were not completely dislodged from the target) at the crater rim. Within this general morphological framework, distinct trends and differences in crater dimensions and morphological characteristics are identified. With increasing impact velocity, the volume of craters in dry targets increases by a factor of ~4 when doubling velocity. At identical impact conditions (steel projectiles, ~5km/s), craters in dry and wet sandstone targets differ significantly in that "wet" craters are up to 76% larger in volume, have depth-diameter ratios generally below 0.19 (whereas dry craters are almost consistently above this value) at significantly larger diameters, and their spallation zone morphologies show very different characteristics. In dry craters, the spall zone surfaces dip evenly at 10-20° towards the crater centre. In wet craters, on the other hand, they consist of slightly convex slopes of 10-35° adjacent to the inner depression, and of sub-horizontal tensile

  12. 基于加速度测量的仪器化冲击试验方法研究%Study on the method of instrumental impact test based on acceleration measurement

    Institute of Scientific and Technical Information of China (English)

    苏文桂; 吴燕瑞; 陈家权; 赵政飞; 温洁明

    2012-01-01

    为研究摆杆在材料冲击过程的动态响应特性及摆杆的振动对测试结果的影响,本文利用虚拟仪器技术构建了一个仪器化冲击测试系统,将加速度传感器用于仪器化冲击试验.试验结果表明,将加速度传感器用于仪器化冲击试验所得的特征曲线与传统仪器化冲击试验特征曲线一致,用加速度传感器测出的数据计算出的冲击功与试验机表盘读数吻合,因此将加速度传感器用于仪器化冲击试验是可行的.通过测量试验中冲击试验机摆锤的加速度,分析材料的冲击性能与摆锤振动特性的关系.运用欧拉-伯努利梁理论对摆杆进行横向固有频率分析和对试验中加速度信号进行功率谱密度分析,得到摆杆在冲击载荷作用下的动态响应与材料的韧脆性之间的关系.研究结果表明,冲击功中的裂纹扩展功反映材料的韧脆性,冲击功中的裂纹扩展功越大,材料的韧性越好;材料韧性越好,摆杆的振动低频所占的能量就越高.%In order to investigate the dynamic responses of the striker arm in the impact process, an instrumental impact system was built by using virtual instrument technique to apply accelerometers in the impact tests. Testing results showed that the characteristic curves obtained from instrumented impact test by applying accelerometer are consistent with that from the traditional instrumented impact test and the impact energy calculated with the accelerometer signal data agreed well with the panel reading data, showing that applying accelerometers for impact test is feasible. By measuring the acceleration of the pendulum of charpy impact machine, the vibration characteristics of the pendulum were studied. The relationship between the dynamic response of the striker arm and the impact properties of the given material was built by analyzing the natural frequency of transverse vibration of striker arm, which was calculated by Euler Bernoulli beam

  13. The Asteroid Impact Mission

    Science.gov (United States)

    Carnelli, Ian; Galvez, Andres; Mellab, Karim

    2016-04-01

    The Asteroid Impact Mission (AIM) is a small and innovative mission of opportunity, currently under study at ESA, intending to demonstrate new technologies for future deep-space missions while addressing planetary defense objectives and performing for the first time detailed investigations of a binary asteroid system. It leverages on a unique opportunity provided by asteroid 65803 Didymos, set for an Earth close-encounter in October 2022, to achieve a fast mission return in only two years after launch in October/November 2020. AIM is also ESA's contribution to an international cooperation between ESA and NASA called Asteroid Impact Deflection Assessment (AIDA), consisting of two mission elements: the NASA Double Asteroid Redirection Test (DART) mission and the AIM rendezvous spacecraft. The primary goals of AIDA are to test our ability to perform a spacecraft impact on a near-Earth asteroid and to measure and characterize the deflection caused by the impact. The two mission components of AIDA, DART and AIM, are each independently valuable but when combined they provide a greatly increased scientific return. The DART hypervelocity impact on the secondary asteroid will alter the binary orbit period, which will also be measured by means of lightcurves observations from Earth-based telescopes. AIM instead will perform before and after detailed characterization shedding light on the dependence of the momentum transfer on the asteroid's bulk density, porosity, surface and internal properties. AIM will gather data describing the fragmentation and restructuring processes as well as the ejection of material, and relate them to parameters that can only be available from ground-based observations. Collisional events are of great importance in the formation and evolution of planetary systems, own Solar System and planetary rings. The AIDA scenario will provide a unique opportunity to observe a collision event directly in space, and simultaneously from ground-based optical and

  14. Impact on floating membranes

    CERN Document Server

    Vandenberghe, Nicolas

    2016-01-01

    When impacted by a rigid object, a thin elastic membrane with negligible bending rigidity floating on a liquid pool deforms. Two axisymmetric waves radiating from the impact point propagate. In the first place, a longitudinal wave front -- associated with in-plane deformation of the membrane and traveling at constant speed -- separates an outward stress free domain with a stretched but flat domain. Then, in the stretched domain a dispersive transverse wave travels at a wave speed that depends on the local stretching rate. We study the dynamics of this fluid-body system and we show that the wave dynamics is similar to the capillary waves that propagate at a liquid-gas interface but with a surface tension coefficient that depends on impact speed. We emphasize the role of the stretching in the membrane in the wave dynamics but also in the development of a buckling instability that give rise to radial wrinkles.

  15. Granular Dynamics During Impact

    Science.gov (United States)

    Nordstrom, K. N.; Lim, E.; Harrington, M.; Losert, W.

    2014-06-01

    We study the impact of a projectile onto a bed of 3 mm grains immersed in an index-matched fluid. We vary the amount of prestrain on the sample, strengthening the force chains within the system. We find this affects only the prefactor of the linear depth-dependent term in the stopping force. We propose a simple model to account for the strain dependence of this term, owing to increased pressure in the pile. Interestingly, we find that the presence of the fluid does not affect the impact dynamics, suggesting that dynamic friction is not a factor. Using a laser sheet scanning technique to visualize internal grain motion, we measure the trajectory of each grain throughout an impact. Microscopically, our results indicate that weaker initial force chains result in more irreversible, plastic rearrangements, suggesting static friction between grains does play a substantial role in the energy dissipation.

  16. NASA Lunar Impact Monitoring

    Science.gov (United States)

    Suggs, Robert M.; Moser, D. E.

    2015-01-01

    The MSFC lunar impact monitoring program began in 2006 in support of environment definition for the Constellation (return to Moon) program. Work continued by the Meteoroid Environment Office after Constellation cancellation. Over 330 impacts have been recorded. A paper published in Icarus reported on the first 5 years of observations and 126 calibrated flashes. Icarus: http://www.sciencedirect.com/science/article/pii/S0019103514002243; ArXiv: http://arxiv.org/abs/1404.6458 A NASA Technical Memorandum on flash locations is in press

  17. Global Scale Impacts

    CERN Document Server

    Asphaug, Erik; Jutzi, Martin

    2015-01-01

    Global scale impacts modify the physical or thermal state of a substantial fraction of a target asteroid. Specific effects include accretion, family formation, reshaping, mixing and layering, shock and frictional heating, fragmentation, material compaction, dilatation, stripping of mantle and crust, and seismic degradation. Deciphering the complicated record of global scale impacts, in asteroids and meteorites, will lead us to understand the original planet-forming process and its resultant populations, and their evolution in time as collisions became faster and fewer. We provide a brief overview of these ideas, and an introduction to models.

  18. Dynamic Response and Simulations of Nanoparticle-Enhanced Composites

    Science.gov (United States)

    2007-11-15

    ash based Eco-Core foams were characterized with a Dynatup Model 8250 instrumented impact test system for both notched and un-notched specimens. 3...impact testing were prepared in accordance to Section 7 of ASTM D- 6110-06: "Standard Test Method for Determining the Charpy Impact Resistance of...Notched Specimens of Plastics" [2.11. Sample dimensions for Charpy impact test specimen are shown in Figure 2.1.1. 221/2’ + /2’ A B F C mm in. A 10.16

  19. Impact dynamics instrumentation

    Science.gov (United States)

    Mccormck, R. F.

    1986-01-01

    One of the tasks specified in the NASA Langley controlled impact demonstration (CID) work package was to furnish dynamic instrumentation sensors. The types of instrumentation sensors required were accelerometers for aircraft structural loads measurements, seat belt load cells to measure anthropomorphic dummy responses to the aircraft impact, and strain gage bending bridges to measure the aircraft fuselage and wing bending during impact. The objective in the selection of dynamic instrumentation for the CID was to provide 352 of the highest quality transducers and remain within budget allocation. The transducers that were selected for the CID evaluation process were each subjected to rigorous laboratory acceptance tests and to aircraft fuselage section drop tests at the LaRC Impact Dynamics Research Facility. Data compiled from this series of tests showed the selected transducers to be best suited for the CID mission requirement. The transducers installation technique on the airframe proved successful. The transducer quality assurance was guaranteed through rigorous acceptance testing. Data acquired was 97.0%.

  20. Global protected area impacts.

    Science.gov (United States)

    Joppa, Lucas N; Pfaff, Alexander

    2011-06-01

    Protected areas (PAs) dominate conservation efforts. They will probably play a role in future climate policies too, as global payments may reward local reductions of loss of natural land cover. We estimate the impact of PAs on natural land cover within each of 147 countries by comparing outcomes inside PAs with outcomes outside. We use 'matching' (or 'apples to apples') for land characteristics to control for the fact that PAs very often are non-randomly distributed across their national landscapes. Protection tends towards land that, if unprotected, is less likely than average to be cleared. For 75 per cent of countries, we find protection does reduce conversion of natural land cover. However, for approximately 80 per cent of countries, our global results also confirm (following smaller-scale studies) that controlling for land characteristics reduces estimated impact by half or more. This shows the importance of controlling for at least a few key land characteristics. Further, we show that impacts vary considerably within a country (i.e. across a landscape): protection achieves less on lands far from roads, far from cities and on steeper slopes. Thus, while planners are, of course, constrained by other conservation priorities and costs, they could target higher impacts to earn more global payments for reduced deforestation.

  1. Impact on floating membranes

    Science.gov (United States)

    Vandenberghe, Nicolas; Duchemin, Laurent

    2016-05-01

    When impacted by a rigid body, a thin elastic membrane with negligible bending rigidity floating on a liquid pool deforms. Two axisymmetric waves radiating from the impact point propagate. First, a longitudinal wave front, associated with in-plane deformation of the membrane and traveling at constant speed, separates an outward stress-free domain from a stretched domain. Then, in the stretched domain a dispersive transverse wave travels at a speed that depends on the local stretching rate. The dynamics is found to be self-similar in time. Using this property, we show that the wave dynamics is similar to the capillary waves that propagate at a liquid-gas interface but with a surface tension coefficient that depends on impact speed. During wave propagation, we observe the development of a buckling instability that gives rise to radial wrinkles. We address the dynamics of this fluid-body system, including the rapid deceleration of an impactor of finite mass, an issue that may have applications in the domain of absorption of impact energy.

  2. Environmental Impacts - Coastal Ecosystems

    NARCIS (Netherlands)

    Bakker, J.P.; Baas, Andreas C.W.; Bartholdy, Jesper; Jones, Laurence; Ruessink, B.G.; Temmerman, Stijn; van de Pol, Martijn

    2016-01-01

    This chapter examines the impacts of climate change on the natural coastal ecosystems in the North Sea region. These comprise sandy shores and dunes and salt marshes in estuaries and along the coast. The chapter starts by describing the characteristic geomorphological features of these systems and t

  3. Impact resistant electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Veith, Gabriel M.; Armstrong, Beth L.; Tenhaeff, Wyatt E.; Dudney, Nancy J.

    2017-03-07

    A passively impact resistant composite electrolyte composition includes an electrolyte solvent, up to 2M of an electrolyte salt, and shear thickening ceramic particles having a polydispersity index of no greater than 0.1, an average particle size of in a range of 50 nm to 1 .mu.m, and an absolute zeta potential of greater than .+-.40 mV.

  4. Organizational Impact of RAMS.

    Science.gov (United States)

    Staebler, Mel

    A series of observations is made regarding the potential impact of the Remotely Accessible Management System (RAMS) upon the administrative structure of the Pontiac, Michigan City School System. Nine major results of the district wide needs assessment are reported, and evidence is advanced to support the conclusion that modern educational…

  5. Social Impact Assessment in Europe

    DEFF Research Database (Denmark)

    Larsen, Sanne Vammen; Hansen, Anne Merrild; Lyhne, Ivar

    2015-01-01

    cases, which are characterised by debates and conflicts on social issues. Analysis of the EA statements shows inclusion of a broad range of social impacts. However, the EAs do not fully match the concerns of the public, and social impacts are not always analysed in depth, mitigation measures...... are not suggested or are postponed and the geographical distribution of impacts assessed is biased towards including negative local impacts. We discuss the scope and handling of social impacts, and possible implications. Based on this, we conclude with the view that EA might do the job of handling social impacts...

  6. 76 FR 62442 - Final Environmental Impact Report/Environmental Impact Statement for Upper Truckee River...

    Science.gov (United States)

    2011-10-07

    ... Bureau of Reclamation Final Environmental Impact Report/Environmental Impact Statement for Upper Truckee.... ACTION: Notice of availability. SUMMARY: The final Environmental Impact Report/Environmental Impact... publication of the final Environmental Impact Report/Environmental Impact Statement. ADDRESSES: The...

  7. From Pressures to Impacts

    DEFF Research Database (Denmark)

    Hauschild, Michael Zwicky

    2006-01-01

    materials over manufacture or construction through use to disposal or decommissioning and recycling. It is a holistic tool in the sense that it models all relevant environmental impacts from the global (like climate change and ozone depletion) to the local (like land use) and also the loss of resources......Life cycle assessment (LCA) has been developed as a tool for assessment of the environmental impacts which are caused by the pressures from products or systems, viewed in a life cycle perspective, i.e. covering all stages of the life cycle of the product or system from the extraction of raw....... The framework for LCA has been standardised by the International Standards Organisation, ISO, which identifies four phases – Goal and scope definition, where the goal is defined, the service to be provided by the studied system is quantified in terms of the functional unit of the study, and the product system...

  8. The Cambrian impact hypothesis

    CERN Document Server

    Zhang, Weijia

    2008-01-01

    After a thorough research on the circumstantial changes and the great evolution of life in the Cambrian period, the author propounds such a hypothesis: During the Late Precambrian, about 500-600Ma, a celestial body impacted the Earth. The high temperature ended the great glaciation, facilitated the communication of biological information. The rapid change of Earth environment enkindled the genesis-control system, and released the HSP-90 variations. After the impact, benefited from the protection of the new ozone layer and the energy supplement of the aerobic respiration, those survived underground life exploded. They generated carapaces and complex metabolism to adjust to the new circumstance of high temperature and high pressure. This article uses a large amount of analyses and calculations, and illustrates that this hypothesis fits well with most of the important incidences in astronomic and geologic discoveries.

  9. Unraveling Scientific Impact

    OpenAIRE

    Stremersch, S.; Camacho, N.M.A.; Vanneste, S.; Verniers, I.W.J.

    2014-01-01

    The number of citations a paper receives is the most commonly used measure of scientific impact. In this paper, we study not only the number but also the type of citations that 659 marketing articles generated. We discern five citation types: application, affirmation, negation, review and perfunctory mention (i.e., citing an article only indirectly without really using it). Prior literature in scientometrics recognizes that the former three types, on average, signal a higher level of scientif...

  10. Laser Impact Welding

    OpenAIRE

    Daehn, Glenn S.; Lippold, John; Liu, Deijan; Taber, Geoff; Wang, Huimin

    2012-01-01

    Laser impact welding is a solid-state, collision-based welding process. In this process, laser-generated optical energy is converted to kinetic energy through the ablation at the surface and confinement of the gas generated between a flyer and backing plate. The launch of the flyer can be affected by many factors, for example, backing material, ablative layer, and flyer thickness. In this paper, the effect of three backing materials: glass, polycarbonate and cellophane tape, we...

  11. Visibility and Citation Impact

    OpenAIRE

    Ale Ebrahim, Nader; Salehi, Hadi; Embi, Mohamed Amin; Habibi Tanha, Farid

    2014-01-01

    The number of publications is the first criteria for assessing a researcher output. However, the main measurement for author productivity is the number of citations, and citations are typically related to the paper's visibility. In this paper, the relationship between article visibility and the number of citations is investigated. A case study of two researchers who are using publication marketing tools confirmed that the article visibility will greatly improve the citation impact. Some st...

  12. Visibility and Citation Impact

    OpenAIRE

    Ale Ebrahim, Nader

    2014-01-01

    The number of publications is the first criteria for assessing a researcher output. However, the main measurement for author productivity is the number of citations, and citations are typically related to the paper's visibility. In this paper, the relationship between article visibility and the number of citations is investigated. A case study of two researchers who are using publication marketing tools confirmed that the article visibility will greatly improve the citation impact. Some s...

  13. Visibility and Citation Impact

    OpenAIRE

    Mohamed Amin Embi; Seyed Mohammad Motahar; Nader Ale Ebrahim نادر آل ابراهیم; Hossein gholizadeh; hossein gholizadeh

    2017-01-01

    The number of publications is the first criteria for assessing a researcher output. However, the main measurement for author productivity is the number of citations, and citations are typically related to the paper's visibility. In this paper, the relationship between article visibility and the number of citations is investigated. A case study of two researchers who are using publication marketing tools confirmed that the article visibility will greatly improve the citation impact. Some strat...

  14. Project X Broader Impacts

    CERN Document Server

    Asner, D M; Henderson, S; Plunkett, R; Wootan, D W; Peterson, M A; Senor, D; Tschirhart, R; Grasselino, A; Romanenko, A; MacDougall, G; Heffner, R H

    2013-01-01

    Part-3 of "Project X: Accelerator Reference Design, Physics Opportunities, Broader Impacts". The proposed Project X proton accelerator at Fermilab, with multi-MW beam power and highly versatile beam formatting, will be a unique world-class facility to explore particle physics at the intensity frontier. Concurrently, however, it can also facilitate important scientific research beyond traditional particle physics and provide unprecedented opportunities in applications to problems of great national importance in the nuclear energy and security sector.

  15. Novel Research Impact Indicators

    Directory of Open Access Journals (Sweden)

    Martin Fenner

    2014-04-01

    Full Text Available Citation counts and more recently usage statistics provide valuable information about the attention and research impact associated with scholarly publications. The open access publisher Public Library of Science (PLOS has pioneered the concept of article-level metrics, where these metrics are collected on a per article and not a per journal basis and are complemented by real-time data from the social web or altmetrics: blog posts, social bookmarks, social media and other.

  16. Milestones and impact factors.

    Science.gov (United States)

    Ozonoff, David M; Grandjean, Philippe

    2010-07-08

    Environmental Health has just received its first Impact Factor by Thomson ISI. At a level of 2.48, this achievement is quite satisfactory and places Environmental Health in the top 25% of environmental science journals. When the journal was launched in 2002, it was still unclear whether the Open Access publishing model could be made into a viable commercial enterprise within the biomedical field. During the past eight years, Open Access journals have become widely available, although still covering only about 15% of journal titles. Major funding agencies and institutions, including prominent US universities, now require that researchers publish in Open Access journals. Because of the profound role of scientific journals for the sharing of results and communication between researchers, the advent of Open Access may be of as much significance as the transition from handwriting to printing via moveable type. As Environmental Health is an electronic Open Access journal, the numbers of downloads at the journal website can be retrieved. The top-20 list of articles most frequently accessed shows that all of them have been downloaded over 10,000 times. Back in 2002, the first article published was accessed only 49 times during the following month. A year later, the server had over 1,000 downloads per month, and now the total number of monthly downloads approaches 50,000. These statistics complement the Impact Factor and confirm the viability of Open Access in our field of research. The advent of digital media and its decentralized mode of distribution - the internet - have dramatically changed the control and financing of scientific information dissemination, while facilitating peer review, accelerating editorial handling, and supporting much needed transparency. Both the meaning and means of "having an impact" are therefore changing, as will the degree and way in which scientific journals remain "factors" in that impact.

  17. Impact cratering calculations

    Science.gov (United States)

    Ahrens, Thomas J.; Okeefe, J. D.; Smither, C.; Takata, T.

    1991-01-01

    In the course of carrying out finite difference calculations, it was discovered that for large craters, a previously unrecognized type of crater (diameter) growth occurred which was called lip wave propagation. This type of growth is illustrated for an impact of a 1000 km (2a) silicate bolide at 12 km/sec (U) onto a silicate half-space at earth gravity (1 g). The von Misses crustal strength is 2.4 kbar. The motion at the crater lip associated with this wave type phenomena is up, outward, and then down, similar to the particle motion of a surface wave. It is shown that the crater diameter has grown d/a of approximately 25 to d/a of approximately 4 via lip propagation from Ut/a = 5.56 to 17.0 during the time when rebound occurs. A new code is being used to study partitioning of energy and momentum and cratering efficiency with self gravity for finite-sized objects rather than the previously discussed planetary half-space problems. These are important and fundamental subjects which can be addressed with smoothed particle hydrodynamic (SPH) codes. The SPH method was used to model various problems in astrophysics and planetary physics. The initial work demonstrates that the energy budget for normal and oblique impacts are distinctly different than earlier calculations for silicate projectile impact on a silicate half space. Motivated by the first striking radar images of Venus obtained by Magellan, the effect of the atmosphere on impact cratering was studied. In order the further quantify the processes of meteor break-up and trajectory scattering upon break-up, the reentry physics of meteors striking Venus' atmosphere versus that of the Earth were studied.

  18. Impact craters on Titan

    Science.gov (United States)

    Wood, Charles A.; Lorenz, Ralph; Kirk, Randy; Lopes, Rosaly; Mitchell, Karl; Stofan, Ellen; ,

    2010-01-01

    Five certain impact craters and 44 additional nearly certain and probable ones have been identified on the 22% of Titan's surface imaged by Cassini's high-resolution radar through December 2007. The certain craters have morphologies similar to impact craters on rocky planets, as well as two with radar bright, jagged rims. The less certain craters often appear to be eroded versions of the certain ones. Titan's craters are modified by a variety of processes including fluvial erosion, mass wasting, burial by dunes and submergence in seas, but there is no compelling evidence of isostatic adjustments as on other icy moons, nor draping by thick atmospheric deposits. The paucity of craters implies that Titan's surface is quite young, but the modeled age depends on which published crater production rate is assumed. Using the model of Artemieva and Lunine (2005) suggests that craters with diameters smaller than about 35 km are younger than 200 million years old, and larger craters are older. Craters are not distributed uniformly; Xanadu has a crater density 2-9 times greater than the rest of Titan, and the density on equatorial dune areas is much lower than average. There is a small excess of craters on the leading hemisphere, and craters are deficient in the north polar region compared to the rest of the world. The youthful age of Titan overall, and the various erosional states of its likely impact craters, demonstrate that dynamic processes have destroyed most of the early history of the moon, and that multiple processes continue to strongly modify its surface. The existence of 24 possible impact craters with diameters less than 20 km appears consistent with the Ivanov, Basilevsky and Neukum (1997) model of the effectiveness of Titan's atmosphere in destroying most but not all small projectiles.

  19. Milestones and Impact Factors

    Directory of Open Access Journals (Sweden)

    Grandjean Philippe

    2010-07-01

    Full Text Available Abstract Environmental Health has just received its first Impact Factor by Thomson ISI. At a level of 2.48, this achievement is quite satisfactory and places Environmental Health in the top 25% of environmental science journals. When the journal was launched in 2002, it was still unclear whether the Open Access publishing model could be made into a viable commercial enterprise within the biomedical field. During the past eight years, Open Access journals have become widely available, although still covering only about 15% of journal titles. Major funding agencies and institutions, including prominent US universities, now require that researchers publish in Open Access journals. Because of the profound role of scientific journals for the sharing of results and communication between researchers, the advent of Open Access may be of as much significance as the transition from handwriting to printing via moveable type. As Environmental Health is an electronic Open Access journal, the numbers of downloads at the journal website can be retrieved. The top-20 list of articles most frequently accessed shows that all of them have been downloaded over 10,000 times. Back in 2002, the first article published was accessed only 49 times during the following month. A year later, the server had over 1,000 downloads per month, and now the total number of monthly downloads approaches 50,000. These statistics complement the Impact Factor and confirm the viability of Open Access in our field of research. The advent of digital media and its decentralized mode of distribution - the internet - have dramatically changed the control and financing of scientific information dissemination, while facilitating peer review, accelerating editorial handling, and supporting much needed transparency. Both the meaning and means of "having an impact" are therefore changing, as will the degree and way in which scientific journals remain "factors" in that impact.

  20. Biological Parameters of Impact

    Science.gov (United States)

    1965-09-01

    zone between no effect and gross injury or death . For example, the pilot who survives an aircraft crash, but who is injured or unconscious so that he...Biological effects were limited to one incidence of bradycardia (116 t36 t and three instances of premature ventricular contractions. However. subjeCtiY" I...R.F.Chandler INTRODUCTION -Investigation of the biological effects of abrupt acceleration (impact) was stimulated by the advent of technical advances

  1. Ecotoxicology & Impact on Biodiversity

    Directory of Open Access Journals (Sweden)

    Shanky Bhat

    2013-07-01

    Full Text Available Ecotoxicology can be defined as the ‘study of impacts of pollutants on the structure and function of ecosystems’ it can be by manmade poisonous chemicals and their effect on the environment, it does not include the study of naturally occurring toxins or it is a scientific discipline combining the methods of ecology and toxicology in studying the effects of toxic substances and especially pollutants on the environment. Ecotoxicology is a mix of various discipline ecology, toxicology, analytical chemistry, physiology, molecular biology, and mathematics. Ecotoxicology looks at the impacts of contaminants including populations, pesticides on individuals, natural communities, and ecosystems. Communities of living things and the environments they live in form ecosystems.Ecosystems include rivers, ponds, deserts, grasslands, and forests, and they too can be affected by pesticides. Ecotoxicologists also study what happens to the pesticides themselves, where they go in the environment, how long they last, and how they finally break down. Herein we review what is ecotoxicology, different kinds of toxicants their impact on biodiversity, assessment of toxicity of environmental toxicant.

  2. Preparing for the Impact

    Science.gov (United States)

    2005-05-01

    On July 4, 2005, the NASA Deep Impact spacecraft will visit Comet 9P/Tempel 1. It will launch a 360 kg impactor that should produce a crater on the surface of the comet and a plume of gas and dust. This experiment will be the first opportunity to study the crust and the interior of a comet. As the material inside the comet's nucleus is pristine, it will reveal new information on the early phases of the Solar System. It will also provide scientists with new insight on crater physics, and thereby give a better understanding on the crater record on comets and other bodies in the Solar System. The scientific outcome of the experiment depends crucially on pre-impact and follow-up observations. Before the impact, it is indeed necessary to accumulate a significant amount of data so as to fully characterise the comet, in terms of size, albedo (reflectivity), rotation period, etc. It is also essential to have a good baseline of observations before the impact to unambiguously discriminate the effects of the impact from the natural activity of the comet. Due to the currently limited understanding of the structure of these dirty snowballs - which is a rather precise definition of a comet - it is indeed far from clear what the effect of the impact will be. Although the most likely model predicts the ejection of a plume and a football stadium sized crater, other model predictions vary between the comet simply swallowing the impactor (with barely any visible effect) to the eventual break-up of the nucleus. As part of a very large international collaboration, two teams of astronomers have used ESO's telescopes over several months to do pre-impact monitoring, taking images and spectra of the comet both in the visible and mid-infrared wavebands. These teams make observations typically once per month, using either the 3.6m or the 3.5m NTT telescopes at La Silla. ESO PR Photo 17/05 shows the latest of these monitoring images. Obtained during the night of May 4 to 5 with the EMMI

  3. Impact Crater Collapse

    Science.gov (United States)

    Melosh, H. J.; Ivanov, B. A.

    The detailed morphology of impact craters is now believed to be mainly caused by the collapse of a geometrically simple, bowl-shaped "transient crater." The transient crater forms immediately after the impact. In small craters, those less than approximately 15 km diameter on the Moon, the steepest part of the rim collapses into the crater bowl to produce a lens of broken rock in an otherwise unmodified transient crater. Such craters are called "simple" and have a depth-to-diameter ratio near 1:5. Large craters collapse more spectacularly, giving rise to central peaks, wall terraces, and internal rings in still larger craters. These are called "complex" craters. The transition between simple and complex craters depends on 1/g, suggesting that the collapse occurs when a strength threshold is exceeded. The apparent strength, however, is very low: only a few bars, and with little or no internal friction. This behavior requires a mechanism for temporary strength degradation in the rocks surrounding the impact site. Several models for this process, including acoustic fluidization and shock weakening, have been considered by recent investigations. Acoustic fluidization, in particular, appears to produce results in good agreement with observations, although better understanding is still needed.

  4. Aluminum alloy impact sparkling

    Directory of Open Access Journals (Sweden)

    M. Dudyk

    2008-08-01

    Full Text Available The cast machine parts are widely used in many branches of industry. A very important issue is gaining the appropriate knowledge relating to the application of castings in places of explosion risks including but not limited to mining, chemical industry and rescue works. A possibility of explosion risks occurrence following the impact sparkling of the cast metal parts is still not solved problem in scientific research. In relation to this issue, in this article, the results of the study are presented, and relating to the tendency to impact sparkling of the aluminium alloys used in machine building. On the grounds of the results obtained, it was demonstrated that the registered impact sparkles bunches of feathers from the analyzed alloys: AlSi7Mg, (AK7; AlSi9Mg, (AK9; AlSi6Cu4, (AK64 and AlSi11, (AK11 show significant differences between each other. The quantitative analysis of the temperature distribution and nuclei surface area performed on the example of the alloy AK9 (subjected to defined period of corrosion allows for the statement that they are dangerous in conditions of explosion risk. Following this fact, designers and users of machine parts made from these materials should not use them in conditions where the explosive mixtures occur.

  5. The IMPACT clinic

    Science.gov (United States)

    Tracy, C. Shawn; Bell, Stephanie H.; Nickell, Leslie A.; Charles, Jocelyn; Upshur, Ross E.G.

    2013-01-01

    Abstract Problem addressed The growing number of elderly patients with multiple chronic conditions presents an urgent challenge in primary care. Current practice models are not well suited to addressing the complex health care needs of this patient population. Objective of program The primary objective of the IMPACT (Interprofessional Model of Practice for Aging and Complex Treatments) clinic was to design and evaluate a new interprofessional model of care for community-dwelling seniors with complex health care needs. A secondary objective was to explore the potential of this new model as an interprofessional training opportunity. Program description The IMPACT clinic is an innovative new model of interprofessional primary care for elderly patients with complex health care needs. The comprehensive team comprises family physicians, a community nurse, a pharmacist, a physiotherapist, an occupational therapist, a dietitian, and a community social worker. The model is designed to accommodate trainees from each discipline. Patient appointments are 1.5 to 2 hours in length, during which time a diverse range of medical, functional, and psychosocial issues are investigated by the full interprofessional team. Conclusion The IMPACT model is congruent with ongoing policy initiatives in primary care reform and enhanced community-based care for seniors. The clinic has been pilot-tested in 1 family practice unit and modeled at 3 other sites with positive feedback from patients and families, clinicians, and trainees. Evaluation data indicate that interprofessional primary care models hold great promise for the growing challenge of managing complex chronic disease. PMID:23486816

  6. Measuring impact in research evaluations

    CERN Document Server

    Bornmann, Lutz

    2014-01-01

    Governments all over the world are contemplating the question of where they should distribute public money (to education or to defence, for example). Distribution of money over a number of different areas always makes an issue, implicitly or explicitly, of the impact which can be achieved with investment in any one of them. Science is also affected by this governmental interest in impact; the issue is not only the impact of research on research itself, but on other areas of society. Citations are traditionally used to measure the impact of research on research. It is as yet unclear how the impact of research on other areas of society can be measured. It appears that alternative metrics (altmetrics, such as Twitter counts) might play a key role in this. This paper is concerned with the measurement of citation impact and societal impact, and looks at the basis, the effects and the problems of impact measurement.

  7. Locating the LCROSS Impact Craters

    CERN Document Server

    Marshall, William; Moratto, Zachary; Colaprete, Anthony; Neumann, Gregory; Smith, David; Hensley, Scott; Wilson, Barbara; Slade, Martin; Kennedy, Brian; Gurrola, Eric; Harcke, Leif; 10.1007/s11214-011-9765-0

    2011-01-01

    The Lunar CRater Observations and Sensing Satellite (LCROSS) mission impacted a spent Centaur rocket stage into a permanently shadowed region near the lunar south pole. The Sheperding Spacecraft (SSC) separated \\sim9 hours before impact and performed a small braking maneuver in order to observe the Centaur impact plume, looking for evidence of water and other volatiles, before impacting itself. This paper describes the registration of imagery of the LCROSS impact region from the mid- and near-infrared cameras onboard the SSC, as well as from the Goldstone radar. We compare the Centaur impact features, positively identified in the first two, and with a consistent feature in the third, which are interpreted as a 20 m diameter crater surrounded by a 160 m diameter ejecta region. The images are registered to Lunar Reconnaisance Orbiter (LRO) topographical data which allows determination of the impact location. This location is compared with the impact location derived from ground-based tracking and propagation of...

  8. Impacts of European drought events

    NARCIS (Netherlands)

    Stahl, Kerstin; Kohn, Irene; Blauhut, Veit; Loon, Van Anne F.; Melsen, Lieke A.; Lanen, van Henny A.J.

    2016-01-01

    Drought is a natural hazard that can cause a wide range of impacts affecting the environment, society, and the economy. Providing an impact assessment and reducing vulnerability to these impacts for regions beyond the local scale, spanning political and sectoral boundaries, requires systematic an

  9. Demonstration project as a procedure for accelerating the application of new technology (Charpie Task Force report). Volume II

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-02-01

    This report examines the issues associated with government programs proposed for the ''commercialization'' of new energy technologies; these programs are intended to hasten the pace at which target technologies are adopted by the private sector. The ''commercial demonstration'' is the principal tool used in these programs. Most previous government interventions in support of technological change have focused on R and D and left to the private sector the decision as to adoption for commercial utilization; thus there is relatively little in the way of analysis or experience which bears direct application. The analysis is divided into four sections. First, the role of R, D, and D within the structure of the national energy goals and policies is examined. The issue of ''prices versus gaps'' is described as a crucial difference of viewpoint concerning the role of the government in the future of the energy system. Second, the process of technological change as it occurs with respect to energy technologies is then examined for possible sources of misalignment of social and private incentives. The process is described as a series of investments. Third, correction of these sources of misalignment then becomes the goal of commercial demonstration programs as this goal and the means for attaining it are explored. Government-supported commercialization may be viewed as a subsidy to the introduction stage of the process; the circumstances under which such subsidies are likely to affect the success of the subsequent diffusion stage are addressed. The discussion then turns to the political, legal, and institutional problems. Finally, methods for evaluation and planning of commercial demonstration programs are analyzed. The critical areas of ignorance are highlighted and comprise a research agenda for improved analytical techniques to support decisions in this area.

  10. Test Simulation using Finite Element Method

    Energy Technology Data Exchange (ETDEWEB)

    Ali, M B; Abdullah, S; Nuawi, M Z; Ariffin, A K, E-mail: abgbas@yahoo.com [Department of Mechanical and Materials Engineering, Faculty of Engineering and Built Environment Universiti Kebangsaan Malaysia 43600 Bangi, Selangor (Malaysia)

    2011-02-15

    The dynamic responses of the standard Charpy impact machine are experimentally studied using the relevant data acquisition system, for the purpose of obtaining the impact response. For this reason, the numerical analysis by means of the finite element method has been used for experiment findings. Modelling of the charpy test was performed in order to obtain strain in the striker during the test. Two types of standard charpy specimens fabricated from different materials, i.e. aluminium 6061 and low carbon steel 1050, were used for the impact simulation testing. The related parameters on between different materials, energy absorbed, strain signal, power spectrum density (PSD) and the relationship between those parameters was finally correlated and discussed.

  11. Social Impact, a Theoretical Model

    Directory of Open Access Journals (Sweden)

    Jenny Onyx

    2014-01-01

    Full Text Available This paper constructs a theoretical model of social impact as it applies to civil society organisations. It does so by drawing on the recent literature on the topic as well as recently completed empirical studies. First, the relationship between impact and evaluation is examined. This is followed by an exploration of the capitals, notably social, human, and cultural capital and their interrelationships, as a theoretical base for the explication of social impact. A formal model of social impact is then identified together with a set of basic principles that may be said to define social impact. Finally the implications of the model are discussed for social policy and organisational management.

  12. Granular Dynamics during Impact

    OpenAIRE

    Nordstrom, Kerstin; Lim, Emily; Harrington, Matthew; Losert, Wolfgang

    2013-01-01

    We study the impact of a projectile onto a bed of 3 mm grains immersed in an index-matched fluid. Specifically, we vary the amount of prestrain on the sample, strengthening the force chains within the system. We find this affects only the prefactor of linear depth-dependent term in the stopping force. We therefore attribute this term to pressure within the material, and not the grain-intruder friction as is sometimes suggested. Using a laser sheet scanning technique to visualize internal grai...

  13. Economic Impact of Obesity.

    Science.gov (United States)

    Spieker, Elena A; Pyzocha, Natasha

    2016-03-01

    Parallel to rising obesity rates is an increase in costs associated with excess weight. Estimates of future direct (medical) and indirect (nonmedical) costs related to obesity suggest rising expenditures that will impose a significant economic burden to individuals and society as a whole. This article reviews research on direct and indirect medical costs and future economic trends associated with obesity and associated comorbidities. Cost disparities associated with subsets of the population experiencing higher than average rates of obesity are explored. Finally, potential solutions with the highest estimated impact are offered, and future directions are proposed.

  14. Impacts of March 11

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Feng: The world-shocking September 11 terrorist attacks occurred in the United States in 2001, and two and a half years late the world saw panic-stricken terrorist attacks of the same kind in Spain. Ever since then March 11 has become another day that is engraved on the mind of the people all over the world. The terrorist event in Madrid has not only produced great impact on Spain and other European nations as well as on the common people, but also spurred the European nations to reflect on a series of important issues and to make some adjustments of their policies.

  15. Violent breaking wave impacts

    DEFF Research Database (Denmark)

    Bredmose, Henrik; Peregrine, D.H.; Bullock, G.N.

    2009-01-01

    for a homogeneous mixture of incompressible liquid and ideal gas. This enables a numerical description of both trapped air pockets and the propagation of pressure shock waves through the aerated water. An exact Riemann solver is developed to permit a finite-volume solution to the flow model with smallest possible...... local error. The high pressures measured during wave impacts on a breakwater are reproduced and it is shown that trapped air can be compressed to a pressure of several atmospheres. Pressure shock waves, reflected off nearby surfaces such as the seabed, can lead to pressures comparable with those...

  16. IMPACT fragmentation model developments

    Science.gov (United States)

    Sorge, Marlon E.; Mains, Deanna L.

    2016-09-01

    The IMPACT fragmentation model has been used by The Aerospace Corporation for more than 25 years to analyze orbital altitude explosions and hypervelocity collisions. The model is semi-empirical, combining mass, energy and momentum conservation laws with empirically derived relationships for fragment characteristics such as number, mass, area-to-mass ratio, and spreading velocity as well as event energy distribution. Model results are used for several types of analysis including assessment of short-term risks to satellites from orbital altitude fragmentations, prediction of the long-term evolution of the orbital debris environment and forensic assessments of breakup events. A new version of IMPACT, version 6, has been completed and incorporates a number of advancements enabled by a multi-year long effort to characterize more than 11,000 debris fragments from more than three dozen historical on-orbit breakup events. These events involved a wide range of causes, energies, and fragmenting objects. Special focus was placed on the explosion model, as the majority of events examined were explosions. Revisions were made to the mass distribution used for explosion events, increasing the number of smaller fragments generated. The algorithm for modeling upper stage large fragment generation was updated. A momentum conserving asymmetric spreading velocity distribution algorithm was implemented to better represent sub-catastrophic events. An approach was developed for modeling sub-catastrophic explosions, those where the majority of the parent object remains intact, based on estimated event energy. Finally, significant modifications were made to the area-to-mass ratio distribution to incorporate the tendencies of different materials to fragment into different shapes. This ability enabled better matches between the observed area-to-mass ratios and those generated by the model. It also opened up additional possibilities for post-event analysis of breakups. The paper will discuss

  17. Effect of oblique impact on impact strength of planetesimals

    Science.gov (United States)

    Yasui, Minami; Yoshida, Yusaku; Matsue, Kazuma; Takano, Shota; Arakawa, Masahiko; Ogawa, Kazunori; Okamoto, Chisato

    2016-10-01

    Collisional processes among planetesimals have played an important role for the formation and the evolution of the bodies in the solar system. Some researchers conducted impact experiments to examine the effects of target material, impact velocity, etc., on the impact strength. Planetesimals could collide with each other at various impact angles. Therefore, the effect of impact angle on the impact strength should be examined, but there are only a few studies about oblique impact experiments. In this study, we conducted oblique impact experiments of porous gypsum and glass spheres simulating planetesimals and examined the effect of the impact angle on the impact strength.We used a porous gypsum sphere and a glass sphere as a target. We carried out impact experiments by using two-stage H2 gas gun at Kobe University. A polycarbonate spherical projectile was accelerated at 2 to 7 km/s. The impact angle, θ, changed from 10° to 90° (90° at a head-on impact). The impact phenomena were observed by a high-speed camera to measure the fragment velocities.The impact strength Q* is defined as an energy density Q, which is the kinetic energy of impactor normalized by the target mass, when the largest fragment mass is half of the original target mass. In both cases of porous gypsum and glass targets, the Q* became larger as the θ decreased. We reanalyzed our results by using the effective energy density, Qc*, defined as Qsin2θ and we found that the results of oblique impacts matched with those of a head-on impact. Furthermore, the relationship between the Qc and the normalized largest fragment mass, ml/Mt, could be fitted by ml/Mt=A×Qc-p and the parameters, A and p, were 82.2 and 0.72 for a porous gypsum target and 1.1×106 and 2.12 for a glass target, respectively. We defined the impact strength Qc* by using the Qc, and the Qc* was about 1000 J/kg for both targets. The power p for a glass target was about 3 times larger than that for a porous gypsum target. This means

  18. Impact of COST 271

    Directory of Open Access Journals (Sweden)

    P. A. Bradley

    2004-06-01

    Full Text Available This article discusses the significance of the achievements of the COST 271 Action on science and technology for space weather and telecommunications in Europe and the world. The Action's work has impacted national and international projects and the decision processes. The key words encompassed in the title of COST 271 are «space weather». But as the reader of this Final Report will appreciate, many more topics were addressed during the Action by the large team of workers from a wide range of countries and organisations than this wording would suggest. Relevant to the performance of telecommunication systems that rely on the presence of the ionosphere for propagation support, or that are affected by transmission through it, there have been investigations among other items of solar and magnetosphere disturbances on the ionosphere, satellite and ground-based measurements of the ionosphere, assembly of near-real-time databases of ionosphere information on the Web, studies of planetary and gravity waves in the ionosphere, ionosphere modelling, mapping and forecasting, long-term changes, ray-path deviations in the presence of irregularities, channel-scattering functions, and scintillations on Earth-space paths. The impact of all this work on the outside communities can be considered within three broad headings as follows.

  19. Environment and environmental impacts

    Directory of Open Access Journals (Sweden)

    Rejane de Fátima Victor Vasconcelos

    2009-12-01

    Full Text Available The article shows what can be environmental impacts and how those happen, both by the actions made by human kind and by natural disasters. Another concern of the research is the unstoppable incident of the natural resources destruction, result f the globalization actions and the economy, and that the environment impacts have happen in every direction, independently of the geographic scale, harming the life in earth, without giving importance who is the target. The article made reference to incidents because of the disorder of the environment, the consequences of rural exodus, the improper tourism, and which actions to solve this problem have not been enough. With reference to sustainable development, it is waited that everyone can live under environmental, social and economical equilibrium, and also has reasonable habit, being sensible to the conservation of the environmental practice. The article emphasizes the values as a need in the equilibrium of sustainability, and even made reference to the lost of the country in the sustainable development and that Brazil could have more interest by the cause, mainly in the managing in the use of pesticides e fungicides in agriculture. The concern with the globalized economy is a radical change which the developing countries are facing. The cause affects of pollutions resulting in health problems. The danger that humanity faces with its own action, as predatory fishing, causing aquatic disorder and the invasion of commerce in the area of permanent conservation.

  20. Landscapes Impacted by Light

    Science.gov (United States)

    Arellano, B.; Roca, J.

    2016-06-01

    The gradual spread of urbanization, the phenomenon known under the term urban sprawl, has become one of the paradigms that have characterized the urban development since the second half of the twentieth century and early twenty-first century. However, there is no unanimous consensus about what means "urbanization". The plurality of forms of human settlement on the planet difficult to identify the urbanization processes. The arrival of electrification to nearly every corner of the planet is certainly the first and more meaningful indicator of artificialization of land. In this sense, the paper proposes a new methodology based on the analysis of the satellite image of nighttime lights designed to identify the highly impacted landscapes worldwide and to build an index of Land Impacted by Light per capita (LILpc) as an indicator of the level of urbanization. The used methodology allows the identification of different typologies of urbanized areas (villages, cities or metropolitan areas), as well as "rural", "rurban", "periurban" and "central" landscapes. The study identifies 186,134 illuminated contours (urbanized areas). In one hand, 404 of these contours could be consider as real "metropolitan areas"; and in the other hand, there are 161,821 contours with less than 5,000 inhabitants, which could be identify as "villages". Finally, the paper shows that 44.5 % live in rural areas, 15.5 % in rurban spaces, 26.2 % in suburban areas and only 18.4 % in central areas.

  1. Impacts of Ocean Acidification

    Energy Technology Data Exchange (ETDEWEB)

    Bijma, Jelle (Alfred Wegener Inst., D-27570 Bremerhaven (Germany)) (and others)

    2009-08-15

    There is growing scientific evidence that, as a result of increasing anthropogenic carbon dioxide (CO{sub 2}) emissions, absorption of CO{sub 2} by the oceans has already noticeably increased the average oceanic acidity from pre-industrial levels. This global threat requires a global response. According to the Intergovernmental Panel on Climate Change (IPCC), continuing CO{sub 2} emissions in line with current trends could make the oceans up to 150% more acidic by 2100 than they were at the beginning of the Anthropocene. Acidification decreases the ability of the ocean to absorb additional atmospheric CO{sub 2}, which implies that future CO{sub 2} emissions are likely to lead to more rapid global warming. Ocean acidification is also problematic because of its negative effects on marine ecosystems, especially marine calcifying organisms, and marine resources and services upon which human societies largely depend such as energy, water, and fisheries. For example, it is predicted that by 2100 around 70% of all cold-water corals, especially those in the higher latitudes, will live in waters undersaturated in carbonate due to ocean acidification. Recent research indicates that ocean acidification might also result in increasing levels of jellyfish in some marine ecosystems. Aside from direct effects, ocean acidification together with other global change-induced impacts such as marine and coastal pollution and the introduction of invasive alien species are likely to result in more fragile marine ecosystems, making them more vulnerable to other environmental impacts resulting from, for example, coastal deforestation and widescale fisheries. The Marine Board-ESF Position Paper on the Impacts of Climate Change on the European Marine and Coastal Environment - Ecosystems indicated that presenting ocean acidification issues to policy makers is a key issue and challenge. Indeed, as the consequences of ocean acidification are expected to emerge rapidly and drastically, but are

  2. Impact Crater with Peak

    Science.gov (United States)

    2002-01-01

    (Released 14 June 2002) The Science This THEMIS visible image shows a classic example of a martian impact crater with a central peak. Central peaks are common in large, fresh craters on both Mars and the Moon. This peak formed during the extremely high-energy impact cratering event. In many martian craters the central peak has been either eroded or buried by later sedimentary processes, so the presence of a peak in this crater indicates that the crater is relatively young and has experienced little degradation. Observations of large craters on the Earth and the Moon, as well as computer modeling of the impact process, show that the central peak contains material brought from deep beneath the surface. The material exposed in these peaks will provide an excellent opportunity to study the composition of the martian interior using THEMIS multi-spectral infrared observations. The ejecta material around the crater can is well preserved, again indicating relatively little modification of this landform since its initial creation. The inner walls of this approximately 18 km diameter crater show complex slumping that likely occurred during the impact event. Since that time there has been some downslope movement of material to form the small chutes and gullies that can be seen on the inner crater wall. Small (50-100 m) mega-ripples composed of mobile material can be seen on the floor of the crater. Much of this material may have come from the walls of the crater itself, or may have been blown into the crater by the wind. The Story When a meteor smacked into the surface of Mars with extremely high energy, pow! Not only did it punch an 11-mile-wide crater in the smoother terrain, it created a central peak in the middle of the crater. This peak forms kind of on the 'rebound.' You can see this same effect if you drop a single drop of milk into a glass of milk. With craters, in the heat and fury of the impact, some of the land material can even liquefy. Central peaks like the one

  3. Accounting for Universities’ Impact

    DEFF Research Database (Denmark)

    Perkmann, Markus; Fini, Riccardo; Ross, Jan-Michael

    2015-01-01

    We present an approach that aims to comprehensively account for scientists’ academic engagement and commercialization activities. While previous research has pointed to the economic and social impact of these activities, it has also been hampered by the difficulties of accurately quantifying them....... Our approach complements university administrative records with data retrieved from external sources and surveys to quantify academic consulting, patenting, and academic entrepreneurship. This allows us to accurately account for ‘independent’ activity, i.e., academic engagement and commercialization...... by not accounting for independent activities. However, with the exception of consulting, we find no significant differences between individuals involved in supported (university-recorded) and independent activity, respectively. Our study contributes to work concerned with developing appropriate and accurate...

  4. Economic Impact of Tourism

    Directory of Open Access Journals (Sweden)

    Gabriela PĂDURE

    2005-10-01

    Full Text Available As the traffic of tourists increased in a particular area, it was observed that environmental and ecological balances were disturbed due toover commercialization. The scenic beauty was made more ‘customer friendly’ and the natural tourism products more accessible and ‘saleable’ byman. Environmentalists are agitated about the damages and carelessness showed by the tourists. Culturally and socially, tourism can impact thedestination country, but its effect cannot be solely attributable to simple tourist activities. On the road to development, tourism products have alsowitnessed some changes. As the world changed and developed, new necessities were identified. As people became more aware, the needs changedand new tourism products were developed to satisfy these new found needs. The last few years have seen the emergence of new areas in tourism like,special interest tourism, green tourism, eco tourism, social tourism and so on.

  5. CITYZEN climate impact studies

    Energy Technology Data Exchange (ETDEWEB)

    Schutz, Martin (ed.)

    2011-07-01

    We have estimated the impact of climate change on the chemical composition of the troposphere due to changes in climate from current climate (2000-2010) looking 40 years ahead (2040-2050). The climate projection has been made by the ECHAM5 model and was followed by chemistry-transport modelling using a global model, Oslo CTM2 (Isaksen et al., 2005; Srvde et al., 2008), and a regional model, EMEP. In this report we focus on carbon monoxide (CO) and surface ozone (O3) which are measures of primary and secondary air pollution. In parallel we have estimated the change in the same air pollutants resulting from changes in emissions over the same time period. (orig.)

  6. Milestones and impact factors

    DEFF Research Database (Denmark)

    Ozonoff, David M; Grandjean, Philippe

    2010-01-01

    universities, now require that researchers publish in Open Access journals. Because of the profound role of scientific journals for the sharing of results and communication between researchers, the advent of Open Access may be of as much significance as the transition from handwriting to printing via moveable...... type. As Environmental Health is an electronic Open Access journal, the numbers of downloads at the journal website can be retrieved. The top-20 list of articles most frequently accessed shows that all of them have been downloaded over 10,000 times. Back in 2002, the first article published...... was accessed only 49 times during the following month. A year later, the server had over 1,000 downloads per month, and now the total number of monthly downloads approaches 50,000. These statistics complement the Impact Factor and confirm the viability of Open Access in our field of research. The advent...

  7. Communication impacting financial markets

    Science.gov (United States)

    Vitting Andersen, Jørgen; Vrontos, Ioannis; Dellaportas, Petros; Galam, Serge

    2014-10-01

    Since the attribution of the Nobel prize in 2002 to Kahneman for prospect theory, behavioral finance has become an increasingly important subfield of finance. However the main parts of behavioral finance, prospect theory included, understand financial markets through individual investment behavior. Behavioral finance thereby ignores any interaction between participants. We introduce a socio-financial model (Vitting Andersen J. and Nowak A., An Introduction to Socio-Finance (Springer, Berlin) 2013) that studies the impact of communication on the pricing in financial markets. Considering the simplest possible case where each market participant has either a positive (bullish) or negative (bearish) sentiment with respect to the market, we model the evolution of the sentiment in the population due to communication in subgroups of different sizes. Nonlinear feedback effects between the market performance and changes in sentiments are taken into account by assuming that the market performance is dependent on changes in sentiments (e.g., a large sudden positive change in bullishness would lead to more buying). The market performance in turn has an impact on the sentiment through the transition probabilities to change an opinion in a group of a given size. The idea is that if for example the market has observed a recent downturn, it will be easier for even a bearish minority to convince a bullish majority to change opinion compared to the case where the meeting takes place in a bullish upturn of the market. Within the framework of our proposed model, financial markets stylized facts such as volatility clustering and extreme events may be perceived as arising due to abrupt sentiment changes via ongoing communication of the market participants. The model introduces a new volatility measure which is apt of capturing volatility clustering and from maximum-likelihood analysis we are able to apply the model to real data and give additional long term insight into where a market is

  8. Reducing the impact.

    Science.gov (United States)

    Mahathir, M

    1997-01-01

    In Asia, attempts to control HIV/AIDS through education have not achieved the necessary behavior changes. This is especially true for young women who are unable to apply their knowledge to their sex behavior because of inequalities in gender relations. Thus, the impact of AIDS on women is significantly greater in settings where the status of women is low. Women in developing countries are at greatest risk because the epidemic is fueled by poverty, lack of information, and lack of autonomy. Prosperity in a developing country, such as Malaysia, entails its own risks because it creates new social norms and values that exist in tandem with debilitating old norms, such as the patriarchy that disempowers women and a resurgence in polygamy and wife abandonment. Subservient gender roles not only increase women's chances of infection, they also target women as the primary caregivers for infected individuals. Young girls may have to abandon school to care for infected parents, and female health care providers are assigned to the lowest ranks of the profession. While most women have been infected by their husbands, they must also bear the stigma of being considered immoral infectors of their husbands. The futures of AIDS widows and orphans is jeopardized by the discrimination that attends the disease, and if the mother dies, her young children face a higher death rate. In settings new to the epidemic, it is difficult to convince men of the importance of addressing women's needs and of seeking the input of women in policy and program development. Only by empowering both sexes to work together to protect society will there be a reasonable chance of reducing the impact of HIV/AIDS.

  9. LANDSCAPES IMPACTED BY LIGHT

    Directory of Open Access Journals (Sweden)

    B. Arellano

    2016-06-01

    Full Text Available The gradual spread of urbanization, the phenomenon known under the term urban sprawl, has become one of the paradigms that have characterized the urban development since the second half of the twentieth century and early twenty-first century. However, there is no unanimous consensus about what means "urbanization". The plurality of forms of human settlement on the planet difficult to identify the urbanization processes. The arrival of electrification to nearly every corner of the planet is certainly the first and more meaningful indicator of artificialization of land. In this sense, the paper proposes a new methodology based on the analysis of the satellite image of nighttime lights designed to identify the highly impacted landscapes worldwide and to build an index of Land Impacted by Light per capita (LILpc as an indicator of the level of urbanization. The used methodology allows the identification of different typologies of urbanized areas (villages, cities or metropolitan areas, as well as “rural”, “rurban”, “periurban” and “central” landscapes. The study identifies 186,134 illuminated contours (urbanized areas. In one hand, 404 of these contours could be consider as real “metropolitan areas”; and in the other hand, there are 161,821 contours with less than 5,000 inhabitants, which could be identify as “villages”. Finally, the paper shows that 44.5 % live in rural areas, 15.5 % in rurban spaces, 26.2 % in suburban areas and only 18.4 % in central areas.

  10. Dynamic Failure of Integrated Durable Hot Structure for Space Access Vehicles

    Science.gov (United States)

    2009-08-01

    hopkinson pressure bar loaded instrumented charpy impact test ,” Engineering Fracture Mechanics, vol. 71, pp. 279–287, 2004. 111 [13] J. Dally and D... instrumented charpy impact test ,” Engineering Fracture Mechanics, vol. 71, pp. 279–287, 2004. Jiang, C.P. Zou, Z. Z. W. D. and Liu, Y. W., “A discussion...SHPB apparatus. A three-point bending test specimen was machined from Ti/TiB plate using EDM technique. The crack was made using EDM wire of 0.002

  11. Microstructural and Fractographic Characterization of a Thermally Embrittled Nuclear Grade Steel: Part I - Annealing

    Directory of Open Access Journals (Sweden)

    Tarpani José R.

    2002-01-01

    Full Text Available A nuclear reactor pressure vessel steel was submitted to different annealing heat treatments aimed at simulating neutron irradiation damage. The obtained microstructures were mechanically tested with subsequent metallographic and fractographic characterization. The relevant microstructural and fractographic aspects were employed in the interpretation of the mechanical behavior of the microstructures in both quasi-static (J-R curve and dynamic (Charpy impact loading regimes. A well defined relationship was determined between the elastic-plastic fracture toughness parameter J-integral and the Charpy impact energy for very most of the microstructures.

  12. Concrete structures under projectile impact

    CERN Document Server

    Fang, Qin

    2017-01-01

    In this book, the authors present their theoretical, experimental and numerical investigations into concrete structures subjected to projectile and aircraft impacts in recent years. Innovative approaches to analyze the rigid, mass abrasive and eroding projectile penetration and perforation are proposed. Damage and failure analyses of nuclear power plant containments impacted by large commercial aircrafts are numerically and experimentally analyzed. Ultra-high performance concrete materials and structures against the projectile impact are developed and their capacities of resisting projectile impact are evaluated. This book is written for the researchers, engineers and graduate students in the fields of protective structures and terminal ballistics.

  13. Management of multiple impacted teeth

    Directory of Open Access Journals (Sweden)

    Nidhi Bansal

    2012-01-01

    Full Text Available An impacted or missing permanent tooth can add significant complications to an otherwise straightforward case. When multiple impacted teeth are present, the case complexity increases further. Developing a treatment sequence, determining appropriate anchorage, and planning and executing sound biomechanics can be a challenge. The following case report illustrates a patient with three retained primary teeth and three impacted permanent canines. After careful treatment planning and extraction of multiple primary teeth;, followed by attempted guided eruption of impacted teeth, the patient finished with a significantly improved functional and aesthetic result.

  14. [Impacts of numerology on acupuncture].

    Science.gov (United States)

    Chen, Min; Wu, Changqiu; Wu, Xueyi

    2016-04-01

    Numerology has a long history in China and has the profound impacts on every academic field in TCM, with acupuncture involved. In this paper, the impacts on acupuncture were discussed in different aspects such as the numbers of meridians, the length of meridian, the time taboo of acupuncture, acupuncture manipulation and time acupuncture. It was found that numerology had laid the critical impact on acupuncture and had the profound imprint nowadays. It is of great significance to study the numerology theory in its impacts on acupuncture, in the exploration on the theories behind acupuncture as well as the comprehensive understanding of acupuncture.

  15. Grain boundary chemistry and heat treatment effects on the ductile-to-brittle transition behavior of vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, R.J.; Hamilton, M.L.; Li, H. [Pacific Northwest National Lab., Richland, WA (United States)

    1998-03-01

    One-third scale Charpy impact specimens of V-4Cr-4Ti were given the same heat treatments applied to equivalent specimens of V-5Cr-5Ti. Auger specimens of V-4Cr-4Ti were also heat treated with the Charpy specimens to enable grain boundary chemistry measurements. The microstructural, microchemical and Charpy impact response of V-4Cr-4Ti displayed trends similar to those observed for V-5Cr-5Ti. The results show that grain size plays an important role in determining the ductile-to-brittle transition temperature (DBTT) of these materials and that a threshold level of grain boundary segregant appears to be required to cause grain boundary embrittlement and intergranular fracture.

  16. Correction factors for safe performance of API X65 pipeline steel

    Energy Technology Data Exchange (ETDEWEB)

    Hashemi, Sayyed H. [Department of Mechanical Engineering, the University of Birjand, P.O. Box 97175/615, Birjand (Iran, Islamic Republic of)], E-mail: shhashemi@birjand.ac.ir

    2009-08-15

    Prediction of required Charpy energy for fracture arrest is vital for safe performance of gas transportation pipelines. This is commonly estimated through failure models calibrated in the past on fracture data from combined Charpy tests and full-thickness burst experiments. Unfortunately, such pipeline failure models are unable to correctly predict the minimum arrest toughness of thermo-mechanical controlled rolled (TMCR) steels. To refine the existing failure models, different empirical adjustments have been proposed in recent years. In this paper, similar correction factors were derived from fracture information of instrumented Charpy impact tests on API X65 steel. The contribution of different fracture mechanisms of impact test specimens was determined through energy partitioning analysis. Parts of the energy contribution were correlated then to the source of uncertainty observed in similar experiments. The applied technique was similar to that of previous studies on X70 and X100 steels, and proved to be encouraging in giving consistent results compared to available test data.

  17. 碰撞试验

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Charpy impact test modelling and local approach to fracture, Comparison of paramctric and non-paramerric mcthocis for determining injury rish, CORRELATION ANALYSIS OF AUTOMOBILE CRASH RESPONSES BASED ON WAVELET DECOMPOSITIONS, Correlation study on different bumper impact test method and predicted results, Damage behaior in ceramic plasma-coated and uncoated glass with steel-ball impact。

  18. Correlation between radiation damage and magnetic properties in reactor vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Kempf, R.A., E-mail: kempf@cnea.gov.ar [División Caracterización, GCCN, CAC-CNEA (Argentina); Sacanell, J. [Departamento Física de la Materia Condensada, GIyA, CAC-CNEA, CONICET (Argentina); Milano, J. [División Resonancias Magnéticas, CAB-CNEA, CONICET (Argentina); Guerra Méndez, N. [Departamento Física de la Materia Condensada, GIyA, CAC-CNEA, CONICET (Argentina); Winkler, E.; Butera, A. [División Resonancias Magnéticas, CAB-CNEA, CONICET (Argentina); Troiani, H. [División Física de Metales, CAB-CNEA and Instituto Balseiro (UNCU), CONICET (Argentina); Saleta, M.E. [División Resonancias Magnéticas, CAB-CNEA, CONICET (Argentina); Fortis, A.M. [Departamento Estructura y Comportamiento. Gerencia Materiales-GAEN, CAC-CNEA (Argentina)

    2014-02-01

    Since reactor pressure vessel steels are ferromagnetic, provide a convenient means to monitor changes in the mechanical properties of the material upon irradiation with high energy particles, by measuring their magnetic properties. Here, we discuss the correlation between mechanical and magnetic properties and microstructure, by studying the flux effect on the nuclear pressure vessel steel used in reactors currently under construction in Argentina. Charpy-V notched specimens of this steel were irradiated in the RA1 experimental reactor at 275 °C with two lead factors (LFs), 93 and 183. The magnetic properties were studied by means of DC magnetometry and ferromagnetic resonance. The results show that the coercive field and magnetic anisotropy spatial distribution are sensitive to the LF and can be explained by taking into account the evolution of the microstructure with this parameter. The saturation magnetization shows a dominant dependence on the accumulated damage. Consequently, the mentioned techniques are suitable to estimate the degradation of the reactor vessel steel.

  19. Analysis of fracture toughness in the transition-temperature region of an Mn-Mo-Ni low-alloy steel

    Science.gov (United States)

    Kim, Sangho; Hwang, Byoungchul; Lee, Sunghak; Lee, Sunghak

    2003-06-01

    This study is concerned with the analysis of fracture toughness in the transition region of an Mn-Mo-Ni low-alloy steel, in accordance with the ASTM E1921 standard test method. Elastic-plastic cleavage fracture toughness ( K Jc ) was determined by three-point bend tests, using precracked Charpy V-notch (PCVN) specimens, and relationships between K Jc , the critical component of J ( J c ), critical distance ( X c ), stretch-zone width (SZW), local fracture stress, and plane-strain fracture toughness ( K Ic were discussed on the basis of the cleavage fracture behavior in the transition region. The master curve and the 95 pct confidence curves well explained the variation in the measured K Jc , and the Weibull slope measured on the Weibull plots was consistent with the theoretical slope of 4. Fractographic observation indicated that X c linearly increased with increasing J c , and that the SZW had a good correlation with K Jc , irrespective of the test temperature. In addition, the local fracture stress was independent of the test temperature, because the tempered bainitic steel used in this study showed a propagation-controlled cleavage fracture behavior.

  20. Effects of grain size on fracture toughness in transition temperature region of Mn-Mo-Ni low-alloy steels

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sangho; Lee, Sunghak; Lee, Bong Sang

    2003-10-25

    An investigation was conducted into the effect of grain size on fracture toughness in the transition temperature region of Mn-Mo-Ni low-alloy steels used for nuclear pressure vessels. Three kinds of steels with different austenite grain sizes (AGS) were fabricated by varying the contents of Al and N, and their microstructures and mechanical properties were examined. Elastic-plastic cleavage fracture toughness, K{sub Jc}, was determined by three-point bend tests of precracked Charpy V-notch (PCVN) specimens according to ASTM E1921 standard test method. When the AGS decreased, the total number of carbides increased, while the size and the aspect ratio of carbides decreased. Local fracture stresses, estimated from a theoretical stress distribution in front of a crack tip, were found to be mainly determined by the 92nd% size of carbides. Cross-sectional areas beneath fracture surfaces were observed to understand microstructural features to affect the cleavage crack propagation behavior. The results showed that measured cleavage fracture units were smaller than AGSs, indicating that packet boundaries as well as austenite grain boundaries played an important role in the cleavage crack propagation. Based on the electron back-scatter diffraction (EBSD) results, the cleavage fracture units could also be matched with the effective grain sizes determined by the misorientation tolerance angle of 25 deg.

  1. Relationship between grain size and fracture toughness in transition region of Mn-Mo-Ni low-alloy steels

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Ho; Lee, Sung Hak [Pohang Univ. of Science and Technology, Pohang (Korea, Republic of); Oh, Yong Jun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2002-03-01

    The present study aims at interpreting the effect of grain size on fracture toughness in the transition region of Mn-Mo-Ni low-alloy steels. Three kinds of steels with different austenite grain sizes were fabricated, and their microstructures and mechanical properties were examined. Elastic-plastic cleavage fracture toughness, K{sub Jc}, was determined by 3-point bend tests of precracked Charpy V-notch (PCVN) specimens according to ASTM E1921 standard test method. When the austenite grain size decreased, the total number of carbides increased, while the size and the aspect ratio of carbides decreased. Local fracture stresses, estimated from a theoretical stress distribution in front of a crack tip, were found to be mainly determined by the 92%th size of carbides. Cross-sectional areas beneath fracture surfaces were observed to understand microstructural features to affect the cleavage crack propagation behavior. The results showed that measured cleavage fracture units were smaller than austenite grain sizes, indicating that packet boundaries as well as austenite grain boundaries played an important role in the cleavage crack propagation. Based on the electron back-scatter diffraction (EBSD) results, the cleavage fracture units could also be matched with the effective grain sizes determined by the misorientation tolerance angle of 25 degree.

  2. Reactor pressure vessel structural integrity research

    Energy Technology Data Exchange (ETDEWEB)

    Pennell, W.E.; Corwin, W.R. [Oak Ridge National Lab., TN (United States)

    1995-04-01

    Development continues on the technology used to assess the safety of irradiation-embrittled nuclear reactor pressure vessels (RPVs) containing flaws. Fracture mechanics tests on RPV steel, coupled with detailed elastic-plastic finite-element analyses of the crack-tip stress fields, have shown that (1) constraint relaxation at the crack tip of shallows surface flaws results in increased data scatter but no increase in the lower-bound fracture toughness, (2) the nil ductility temperature (NDT) performs better than the reference temperature for nil ductility transition (RT{sub NDT}) as a normalizing parameter for shallow-flaw fracture toughness data, (3) biaxial loading can reduce the shallow-flaw fracture toughness, (4) stress-based dual-parameter fracture toughness correlations cannot predict the effect of biaxial loading on a shallow-flaw fracture toughness because in-plane stresses at the crack tip are not influenced by biaxial loading, and (5) an implicit strain-based dual-parameter fracture toughness correlation can predict the effect of biaxial loading on shallow-flaw fracture toughness. Experimental irradiation investigations have shown that (1) the irradiation-induced shift in Charpy V-notch vs temperature behavior may not be adequate to conservatively assess fracture toughness shifts due to embrittlement, and (2) the wide global variations of initial chemistry and fracture properties of a nominally uniform material within a pressure vessel may confound accurate integrity assessments that require baseline properties.

  3. Influence of Heat Input on Microstructure and Toughness Properties in Simulated CGHAZ of X80 Steel Manufactured Using High-Temperature Processing

    Science.gov (United States)

    Zhu, Zhixiong; Han, Jian; Li, Huijun

    2015-11-01

    To determine and demonstrate the weldability of high-Nb high-temperature processed (HTP) steels and provide extremely valuable information for future line pipe steel design and general steel manufacture, in the current study the toughness in simulated coarse-grained heat-affected zone (CGHAZ) of an X80 grade steel manufactured using HTP was evaluated. The simulated CGHAZs subjected to thermal cycles with various heat inputs (HIs) (0.8 to 5.0 kJ/mm) were produced using a Gleeble 3500 simulator. The microstructures and corresponding mechanical properties were investigated by means of optical microscopy, scanning electron microscopy, electron backscatter diffraction, hardness testing, and Charpy V-notch (CVN) testing. The microstructural examination shows that the simulated CGHAZs consisted of a bainite-dominant microstructure and relatively low amount (testing suggest that superior toughness can be achieved in the studied range of HIs (0.8 to 5 kJ/mm). This is thought to be associated with the combined effects of bainitic microstructure and low M-A fraction as well as comparatively fine austenite grain size in the studied CGHAZs.

  4. Reactor Materials Program: Mechanical properties of irradiated Types 304 and 304L stainless steel weldment components

    Energy Technology Data Exchange (ETDEWEB)

    Sindelar, R.L.; Caskey, G.R. Jr.

    1991-12-01

    The vessels (reactor tanks) of the Savannah River Site nuclear production reactors constructed in the 1950`s are comprised of Type 304 stainless steel with Type 308 stainless steel weld filler. Irradiation exposure to the reactor tank sidewalls through reactor operation has caused a change in the mechanical properties of these materials. A database of as-irradiated mechanical properties for site-specific materials and irradiation conditions has been produced for reactor tank structural analyses and to quantify the effects of radiation-induced materials degradation for evaluating reactor service life. The data has been collected from the SRL Reactor Materials Program (RMP) irradiations and testing of archival stainless steel weldment components and from previous SRL programs to measure properties of irradiated reactor Thermal Shield weldments and reactor tank (R-tank) sidewall material. Irradiation programs of the RMP are designed to quantify mechanical properties at tank operating temperatures following irradiation to present and future tank wall maximum exposure conditions. The exposure conditions are characterized in terms of fast neutron fluence (E{sub n} > 0.1 MeV) and displacements per atom (dpa){sup 3}. Tensile properties, Charpy-V notch toughness, and elastic-plastic fracture toughness were measured for base, weld, and weld heat-affected zone (HAZ) weldment components from archival piping specimens following a Screening Irradiation in the University of Buffalo Reactor (UBR) and following a Full-Term Irradiation in the High Flux Isotope Reactor (HFIR).

  5. Reactor Materials Program: Mechanical properties of irradiated Types 304 and 304L stainless steel weldment components

    Energy Technology Data Exchange (ETDEWEB)

    Sindelar, R.L.; Caskey, G.R. Jr.

    1991-12-01

    The vessels (reactor tanks) of the Savannah River Site nuclear production reactors constructed in the 1950's are comprised of Type 304 stainless steel with Type 308 stainless steel weld filler. Irradiation exposure to the reactor tank sidewalls through reactor operation has caused a change in the mechanical properties of these materials. A database of as-irradiated mechanical properties for site-specific materials and irradiation conditions has been produced for reactor tank structural analyses and to quantify the effects of radiation-induced materials degradation for evaluating reactor service life. The data has been collected from the SRL Reactor Materials Program (RMP) irradiations and testing of archival stainless steel weldment components and from previous SRL programs to measure properties of irradiated reactor Thermal Shield weldments and reactor tank (R-tank) sidewall material. Irradiation programs of the RMP are designed to quantify mechanical properties at tank operating temperatures following irradiation to present and future tank wall maximum exposure conditions. The exposure conditions are characterized in terms of fast neutron fluence (E{sub n} > 0.1 MeV) and displacements per atom (dpa){sup 3}. Tensile properties, Charpy-V notch toughness, and elastic-plastic fracture toughness were measured for base, weld, and weld heat-affected zone (HAZ) weldment components from archival piping specimens following a Screening Irradiation in the University of Buffalo Reactor (UBR) and following a Full-Term Irradiation in the High Flux Isotope Reactor (HFIR).

  6. Design and fabrication report on instrumented capsule (99M-01K.02H) for korean reactor pressure vessel material made by HANJUNG (Co)

    Energy Technology Data Exchange (ETDEWEB)

    Choo, K. N.; Kang, Y. H.; Kim, B. G.; Cho, M. S.; Son, J. M.; Kim, D. S.; Oh, J. M.; Park, S. J.; Shin, Y. T

    2000-09-01

    The instrumented capsules (99M-01K{center_dot}02H) was designed and fabricated. The purpose of the capsules were to evaluate the nuclear irradiation performance of the Korean nuclear reactor pressure vessel material, SA508 class 3 steel, fabricated by HANJUNG Co for Yonggwang Units 4,5 and Ulchin Unit 4. There are 5 stages having specimens and independent electric heaters in the capsule mainbody. 12 K-type thermocouples and 5 sets of Ni-Ti-Fe and sapphire neutron Fluence Monitors were also inserted in the apsule. Various types of specimens, such as round compact tension, Charpy insert, pre-cracked v-notch (PCVN), tensile, small punch (SP), magnetic Barkhausen effect (MBE), and transmission electron micrograph (TEM) specimens, were inserted in the capsule. The capsule was fabricated at DAEWOO Precision Co. according to KAERI detailed design specifications. This report describes the details of the design, fabrication and inspection of the 99M-01K and 99M-02H capsule. The capsules were irradiated in the IR2 test hole of HANARO at 290{+-}10 deg C up to the fast neutron fluence (E>1.0 MeV) of 3.0x10{sup 19} (n/cm{sup 2})

  7. Radiological impacts of phosphogypsum.

    Science.gov (United States)

    Al Attar, Lina; Al-Oudat, Mohammad; Kanakri, Salwa; Budeir, Youssef; Khalily, Hussam; Al Hamwi, Ahmad

    2011-09-01

    This study was carried out to assess the radiological impact of Syrian phosphogypsum (PG) piles in the compartments of the surrounding ecosystem. Estimating the distribution of naturally occurring radionuclides (i.e. (226)Ra, (238)U, (232)Th, (210)Po and (210)Pb) in the raw materials, product and by-product of the Syrian phosphate fertilizer industry was essential. The data revealed that the concentrations of the radionuclides were enhanced in the treated phosphate ore. In PG, (226)Ra content had a mean activity of 318 Bq kg(-1). The uranium content in PG was low, ca. 33 Bq kg(-1), because uranium remained in the phosphoric acid produced. Over 80% of (232)Th, (210)Po and (210)Pb present partitioned in PG. The presence of PG piles did not increase significantly the concentration of (222)Rn or gamma rays exposure dose in the area studied. The annual effective dose was only 0.082 mSv y(-1). The geometric mean of total suspended air particulates (TSP) ca. 85 μg m(-3). The activity concentration of the radionuclides in filtrates and runoff waters were below the detection limits (ca. 0.15 mBq L(-1) for (238)U, 0.1 mBq L(-1) for (232)Th and 0.18 mBq L(-1) for both of (210)Po and (210)Pb); the concentration of the radionuclides in ground water samples and Qattina Lake were less than the permissible limits set for drinking water by the World Health Organisation, WHO, (10, 1 and 0.1 Bq L(-1) for (238)U, (232)Th and both of (210)Po and (210)Pb, respectively). Eastern sites soil samples of PG piles recorded the highest activity concentrations, i.e. 26, 33, 28, 61 and 40 Bq kg(-1) for (226)Ra, (238)U, (232)Th, (210)Po and (210)Pb, respectively, due to the prevailing western and north-western wind in the area, but remained within the natural levels reported in Syrian soil (13-32 Bq kg(-1) for (226)Ra, 24.9-62.2 Bq kg(-1) for (238)U and 10-32 Bq kg(-1) for (232)Th). The impact of PG piles on plants varied upon the plant species. Higher concentrations of the radionuclides were

  8. The Impact of Odors

    Directory of Open Access Journals (Sweden)

    M. V. Jokl

    2002-01-01

    Full Text Available The odor microclimate is formed by gaseous airborne components perceived either as an unpleasant smell or as a pleasant smell. Smells enter the building interior partly from outdoors (exhaust fumes - flower fragrance and partly from indoors (building materials, smoking cigarettes - cosmetics, dishes. They affect the human organism through the olfactory center which is connected to the part of brain that is responsible for controlling people’s emotions and sexual feelings: smells therefore participate to a high level in mood formation. The sense of smell diminishes slowly in people over the age of 60, but all female age categories have a better sense of smell than males. Smell is extremely sensitive, e.g., during pregnancy, or if an illness is coming. Bad smells cause a decrease in human performance, loss of concentration, and loss of taste. Sweet smells have a positive impact on human feelings and on human performance. Criteria for odor microclimate appraisal are presented (concentration limits of CO2 , TVOC, plf, decipol, decicarbdiox, decitvoc.

  9. Research impact: a narrative review.

    Science.gov (United States)

    Greenhalgh, Trisha; Raftery, James; Hanney, Steve; Glover, Matthew

    2016-05-23

    Impact occurs when research generates benefits (health, economic, cultural) in addition to building the academic knowledge base. Its mechanisms are complex and reflect the multiple ways in which knowledge is generated and utilised. Much progress has been made in measuring both the outcomes of research and the processes and activities through which these are achieved, though the measurement of impact is not without its critics. We review the strengths and limitations of six established approaches (Payback, Research Impact Framework, Canadian Academy of Health Sciences, monetisation, societal impact assessment, UK Research Excellence Framework) plus recently developed and largely untested ones (including metrics and electronic databases). We conclude that (1) different approaches to impact assessment are appropriate in different circumstances; (2) the most robust and sophisticated approaches are labour-intensive and not always feasible or affordable; (3) whilst most metrics tend to capture direct and proximate impacts, more indirect and diffuse elements of the research-impact link can and should be measured; and (4) research on research impact is a rapidly developing field with new methodologies on the horizon.

  10. Environmental Impact Assessment: A Procedure.

    Science.gov (United States)

    Stover, Lloyd V.

    Prepared by a firm of consulting engineers, this booklet outlines the procedural "whys and hows" of assessing environmental impact, particularly for the construction industry. Section I explores the need for environmental assessment and evaluation to determine environmental impact. It utilizes a review of the National Environmental Policy Act and…

  11. The impact of 'terminator' technology

    NARCIS (Netherlands)

    Visser, B.; Meer, van der I.J.M.; Louwaars, N.; Beekwilder, J.; Eaton, D.

    2001-01-01

    Genetic use-restriction technologies enable the developers of transgenic plants or animals to protect their variety or breed from unauthorized use in a biological way. The use of 'terminator technology' can have different impacts on farmers and breeders. If the technology is effective, it impacts on

  12. Research Impact and Educational Research

    Science.gov (United States)

    Oancea, Alis

    2013-01-01

    Based on a 2010-11 study involving senior researchers from seven disciplines, this article explores critically some of the diverse interpretations of impact in different disciplines, sub-fields and modes of research, and researchers' views about how these interpretations articulate with top-down impact agendas and with university structures…

  13. Ejecta evolution during cone impact

    KAUST Repository

    Marston, Jeremy

    2014-07-07

    We present findings from an experimental investigation into the impact of solid cone-shaped bodies onto liquid pools. Using a variety of cone angles and liquid physical properties, we show that the ejecta formed during the impact exhibits self-similarity for all impact speeds for very low surface tension liquids, whilst for high-surface tension liquids similarity is only achieved at high impact speeds. We find that the ejecta tip can detach from the cone and that this phenomenon can be attributed to the air entrainment phenomenon. We analyse of a range of cone angles, including some ogive cones, and impact speeds in terms of the spatiotemporal evolution of the ejecta tip. Using superhydrophobic cones, we also examine the entry of cones which entrain an air layer.

  14. Black hole accretion disc impacts

    CERN Document Server

    Pihajoki, Pauli

    2015-01-01

    We present an analytic model for computing the luminosity and spectral evolution of flares caused by a supermassive black hole impacting the accretion disc of another supermassive black hole. Our model includes photon diffusion, emission from optically thin regions and relativistic corrections to the observed spectrum and time-scales. We test the observability of the impact scenario with a simulated population of quasars hosting supermassive black hole binaries. The results indicate that for a moderate binary mass ratio of 0.3, and impact distances of 100 primary Schwarzschild radii, the accretion disc impacts can be expected to equal or exceed the host quasar in brightness at observed wavelength {\\lambda} = 510 nm up to z = 0.6. We conclude that accretion disc impacts may function as an independent probe for supermassive black hole binaries. We release the code used for computing the model light curves to the community.

  15. Guidance law with impact time and impact angle constraints

    Institute of Scientific and Technical Information of China (English)

    Zhang Youan; Ma Guoxin; Liu Aili

    2013-01-01

    A novel closed-form guidance law with impact time and impact angle constraints is proposed for salvo attack of anti-ship missiles,which employs missile's normal acceleration (not jerk) as the control command directly.Firstly,the impact time control problem is formulated as tracking the designated time-to-go (the difference between the designated impact time and the current flight time) for the actual time-to-go of missile,and the impact angle control problem is formulated as tracking the designated heading angle for the actual heading angle of missile.Secondly,a biased proportional navigation guidance (BPNG) law with designated heading angle constraint is constructed,and the actual time-to-go estimation for this BPNG is derived analytically by solving the system differential equations.Thirdly,by adding a feedback control to this constructed BPNG to eliminate the time-to-go error-the difference between the standard time-to-go and the actual time-to-go,a guidance law with adjustable coefficients to control the impact time and impact angle simultaneously is developed.Finally,simulation results demonstrate the performance and feasibility of the proposed approach.

  16. Einstein His Impact on Accelerators; His Impact on the World

    CERN Document Server

    Sessler, Andrew M

    2005-01-01

    The impact of the work of Albert Einstein on accelerator physics is described. Because of the limit of time, and also because the audience knows the details, the impact is described in broad strokes. Nevertheless, it is seen how his work has affected many different aspects of accelerator physics. In the second half of the talk, Albert Einstein's impact on the world will be discussed; namely his work on world peace (including his role as a pacifist, in the atomic bomb, and in arms control) and his efforts as a humanitarian (including his efforts on social justice, anti-racism, and civil rights).

  17. Behind the scenes of GS: the impact of IMPACT

    CERN Multimedia

    Katarina Anthony

    2014-01-01

    Carrying out a job at CERN can be a complicated task, with coordinators reaching across departments to manage personnel, ensure safety and minimise the impact of their activities on the rest of the Laboratory.  To help coordinators with this tough task, the GS Department developed IMPACT, the platform that, since 2011, has unified CERN's major experiment, accelerator and injector coordination tools.   When planning interventions both large and small, IMPACT (the Intervention Management Planning and Coordination Tool) is the go-to gizmo on every CERN coordinator's tool belt. "IMPACT is a central repository of activity requests that standardises the way work is declared at CERN," says Benoit Daudin, GS-AIS-PM Section Leader. "If you need to intervene in any of CERN's major facilities, you need to declare this work on IMPACT. The tool will analyse the job and see whose approval is required. This could simply b...

  18. Author Impact Factor: tracking the dynamics of individual scientific impact.

    Science.gov (United States)

    Pan, Raj Kumar; Fortunato, Santo

    2014-05-12

    The impact factor (IF) of scientific journals has acquired a major role in the evaluations of the output of scholars, departments and whole institutions. Typically papers appearing in journals with large values of the IF receive a high weight in such evaluations. However, at the end of the day one is interested in assessing the impact of individuals, rather than papers. Here we introduce Author Impact Factor (AIF), which is the extension of the IF to authors. The AIF of an author A in year t is the average number of citations given by papers published in year t to papers published by A in a period of Δt years before year t. Due to its intrinsic dynamic character, AIF is capable to capture trends and variations of the impact of the scientific output of scholars in time, unlike the h-index, which is a growing measure taking into account the whole career path.

  19. Author Impact Factor: tracking the dynamics of individual scientific impact

    Science.gov (United States)

    Pan, Raj Kumar; Fortunato, Santo

    2014-05-01

    The impact factor (IF) of scientific journals has acquired a major role in the evaluations of the output of scholars, departments and whole institutions. Typically papers appearing in journals with large values of the IF receive a high weight in such evaluations. However, at the end of the day one is interested in assessing the impact of individuals, rather than papers. Here we introduce Author Impact Factor (AIF), which is the extension of the IF to authors. The AIF of an author A in year t is the average number of citations given by papers published in year t to papers published by A in a period of Δt years before year t. Due to its intrinsic dynamic character, AIF is capable to capture trends and variations of the impact of the scientific output of scholars in time, unlike the h-index, which is a growing measure taking into account the whole career path.

  20. Author Impact Factor: tracking the dynamics of individual scientific impact

    CERN Document Server

    Pan, Raj Kumar

    2013-01-01

    The impact factor (IF) of scientific journals has acquired a major role in the evaluations of the output of scholars, departments and whole institutions. Typically papers appearing in journals with large values of the IF receive a high weight in such evaluations. However, at the end of the day one is interested in assessing the impact of individuals, rather than papers. Here we introduce Author Impact Factor (AIF), which is the extension of the IF to authors. The AIF of an author A in year $t$ is the average number of citations given by papers published in year $t$ to papers published by A in a period of $\\Delta t$ years before year $t$. Due to its intrinsic dynamic character, AIF is capable to capture trends and variations of the impact of the scientific output of scholars in time, unlike the $h$-index, which is a growing measure taking into account the whole career path.

  1. Highlighting Impact and the Impact of Highlighting: PRB Editors' Suggestions

    CERN Document Server

    Antonoyiannakis, Manolis

    2016-01-01

    Associate Editor Manolis Antonoyiannakis discusses the highlighting, as Editors' Suggestions, of a small percentage of the papers published each week. We highlight papers primarily for their importance and impact in their respective fields, or because we find them particularly interesting or elegant. It turns out that the additional layer of scrutiny involved in the selection of papers as Editors' Suggestions is associated with a significantly elevated and sustained citation impact.

  2. Effect of microstructure on the impact toughness of high strength steels

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, I.

    2014-07-01

    One of the major challenges in the development of new steel grades is to get increasingly high strength combined with a low ductile brittle transition temperature and a high upper shelf energy. This requires the appropriate microstructural design. Toughness in steels is controlled by different microstructural constituents. Some of them, like inclusions, are intrinsic while others happening at different microstructural scales relate to processing conditions. A series of empirical equations express the transition temperature as a sum of contributions from substitutional solutes, free nitrogen, carbides, pearlite, grain size and eventually precipitation strengthening. Aimed at developing a methodology that could be applied to high strength steels, microstructures with a selected degree of complexity were produced at laboratory in a Nb-microalloyed steel. As a result a model has been developed that consistently predicts the Charpy curves for ferrite-pearlite, bainitic and quenched and tempered microstructures using as input data microstructural parameters. This model becomes a good tool for microstructural design. (Author)

  3. Including social impacts in LCIA

    DEFF Research Database (Denmark)

    Dreyer, Louise Camilla; Hauschild, Michael Zwicky

    2004-01-01

    environmental impacts and, therefore, recommendations based on LCA fail to address both social and economic concerns. This has raised questions about LCA's ability to support sustainable development decisions. In a research project carried out at Brødrene Hartmann A/S and the Technical University of Denmark...... a framework for social LCA is currently being developed. The project quantifies social impacts and makes them operational in the traditional LCIA framework by developing measurable indicators. These indicators are selected to provide a meaningful and sufficient overall description of social impacts of all...

  4. Including social impacts in LCIA

    DEFF Research Database (Denmark)

    Dreyer, Louise Camilla; Hauschild, Michael Zwicky; Schierbeck, Jens

    2004-01-01

    environmental impacts and, therefore, recommendations based on LCA fail to address both social and economic concerns. This has raised questions about LCA's ability to support sustainable development decisions. In a research project carried out at Brødrene Hartmann A/S and the Technical University of Denmark...... a frameowork for social LCA is currently being developed. The project quantifies social impacts and makes them operational in the traditional LCIA framework by developing measureable indicators. These indicators are selected to provide a meaningful and sufficient overall description of social impacts of all...

  5. 78 FR 54906 - Draft Supplemental Environmental Impact Report/Environmental Impact Statement for a Proposed...

    Science.gov (United States)

    2013-09-06

    ... Fish and Wildlife Service Draft Supplemental Environmental Impact Report/Environmental Impact Statement... Coachella Valley Conservation Commission (CVCC), has prepared a joint draft Supplemental Environmental Impact Report/Environmental Impact Statement (draft Supplemental EIR/EIS) under the...

  6. Privacy Impact Assessment (PIA) Repository

    Data.gov (United States)

    Department of Veterans Affairs — This repository contains Privacy Impact Assessments (PIA) that have been vetted/approved. Section 208 of the Electronic Government Act of 2002 (E-Gov Act) requires...

  7. Distributed Impact Detection System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Automated impact detection and characterization on manned spacecraft has been an elusive goal due to the transitory nature of the detectable high-frequency signals....

  8. Drop impact on superheated surfaces

    CERN Document Server

    Tran, Tuan; Prosperetti, Andrea; Sun, Chao; Lohse, Detlef

    2011-01-01

    At impact of a liquid droplet on a smooth surface heated above the liquid's boiling point, the droplet either immediately boils when it contacts the surfaces (``contact boiling''), or without any surface contact forms a Leidenfrost vapor layer towards the hot surface and bounces back (``gentle film boiling''), or both forms the Leidenfrost layer and ejects tiny droplets upward (``spraying film boiling''). We experimentally determine conditions under which impact behaviors in each regime can be realized. We show that the dimensionless maximum spreading $\\gamma$ of impacting droplets on the heated surfaces in both gentle and spraying film boiling regimes shows a universal scaling with the Weber number $\\We$ ($\\gamma\\sim\\We^{2/5}$) -- regardless of surface temperature and of liquid properties -- which is much steeper than for the impact on non-heated (hydrophilic or hydrophobic) surfaces ($\\gamma\\sim\\We^{1/4}$). We also intereferometrically measure the vapor thickness under the droplet.

  9. Drop impact on superheated surfaces.

    Science.gov (United States)

    Tran, Tuan; Staat, Hendrik J J; Prosperetti, Andrea; Sun, Chao; Lohse, Detlef

    2012-01-20

    At the impact of a liquid droplet on a smooth surface heated above the liquid's boiling point, the droplet either immediately boils when it contacts the surface ("contact boiling"), or without any surface contact forms a Leidenfrost vapor layer towards the hot surface and bounces back ("gentle film boiling"), or both forms the Leidenfrost layer and ejects tiny droplets upward ("spraying film boiling"). We experimentally determine conditions under which impact behaviors in each regime can be realized. We show that the dimensionless maximum spreading γ of impacting droplets on the heated surfaces in both gentle and spraying film boiling regimes shows a universal scaling with the Weber number We (γ~We(2/5)), which is much steeper than for the impact on nonheated (hydrophilic or hydrophobic) surfaces (γ~We(1/4)). We also interferometrically measure the vapor thickness under the droplet.

  10. Broadening nanotechnology's impact on development

    NARCIS (Netherlands)

    Beumer, K.

    2016-01-01

    Discussions about nanotechnology and development focus on applications that directly address the needs of the world’s poor. Nanotechnology can certainly make an impact in the fight against global poverty, but we need to broaden our imagination.

  11. Visualizing the Impacts of Deforestation.

    Science.gov (United States)

    Fortner, Rosanne W.

    1992-01-01

    Presents two activities with investigation procedures to aid students in examining the extent and impact of biomass burning and deforestation in Brazil as an example of the global problem. Provides background information, tables, and diagrams. (five references) (MCO)

  12. Social Impact of SSH Research

    DEFF Research Database (Denmark)

    Johansson, Lasse Gøhler; Grønvad, Jonas Følsgaard; Pedersen, David Budtz

    2016-01-01

    of making social impact. However, the social sciences and humanities (SSH) have only played a marginal role in the societal challenges of Horizon2020. According to Science Europe, the pan-European association for research councils and foundations, only 26.7 percent of the topics under the Horizon2020’s...... societal challenges explicitly invite contributions from SSH research. If we look at the humanities in isolation, it is only around 10 percent of the topics. The marginal role of SSH in Horizon2020 is, among other things, the result of an inadequate understanding of the social impact of SSH research...... and of inadequate instruments for measuring the impact of SSH research. In this paper we address the following questions: 1) how can we understand the social impact of SSH research? And 2) how can we meaningfully measure or assess it? These questions are addressed through a survey of the current scientific...

  13. Climate Impacts on Human Health

    Science.gov (United States)

    ... more rapidly in warm environments. These diseases can cause gastrointestinal distress and, in severe cases, death. [1] Practices to safeguard food can help avoid these illnesses even as the climate changes. Climate change will have a variety of impacts ...

  14. Impact of conflict in Africa

    Directory of Open Access Journals (Sweden)

    Kathryn Touré

    2006-07-01

    Full Text Available Since independence, few African countries have beenspared violence and armed conflict. Two West Africanresearch networks recently organised an internationalcolloquium to assess the impact and develop linkagesbetween education, peace and democracy.

  15. Broadening nanotechnology's impact on development

    Science.gov (United States)

    Beumer, Koen

    2016-05-01

    Discussions about nanotechnology and development focus on applications that directly address the needs of the world's poor. Nanotechnology can certainly make an impact in the fight against global poverty, but we need to broaden our imagination.

  16. Swept Impact Seismic Technique (SIST)

    Science.gov (United States)

    Park, C.B.; Miller, R.D.; Steeples, D.W.; Black, R.A.

    1996-01-01

    A coded seismic technique is developed that can result in a higher signal-to-noise ratio than a conventional single-pulse method does. The technique is cost-effective and time-efficient and therefore well suited for shallow-reflection surveys where high resolution and cost-effectiveness are critical. A low-power impact source transmits a few to several hundred high-frequency broad-band seismic pulses during several seconds of recording time according to a deterministic coding scheme. The coding scheme consists of a time-encoded impact sequence in which the rate of impact (cycles/s) changes linearly with time providing a broad range of impact rates. Impact times used during the decoding process are recorded on one channel of the seismograph. The coding concept combines the vibroseis swept-frequency and the Mini-Sosie random impact concepts. The swept-frequency concept greatly improves the suppression of correlation noise with much fewer impacts than normally used in the Mini-Sosie technique. The impact concept makes the technique simple and efficient in generating high-resolution seismic data especially in the presence of noise. The transfer function of the impact sequence simulates a low-cut filter with the cutoff frequency the same as the lowest impact rate. This property can be used to attenuate low-frequency ground-roll noise without using an analog low-cut filter or a spatial source (or receiver) array as is necessary with a conventional single-pulse method. Because of the discontinuous coding scheme, the decoding process is accomplished by a "shift-and-stacking" method that is much simpler and quicker than cross-correlation. The simplicity of the coding allows the mechanical design of the source to remain simple. Several different types of mechanical systems could be adapted to generate a linear impact sweep. In addition, the simplicity of the coding also allows the technique to be used with conventional acquisition systems, with only minor modifications.

  17. AIDA: Asteroid Impact & Deflection Assessment

    Science.gov (United States)

    Cheng, A. F.; Galvez, A.; Carnelli, I.; Michel, P.; Rivkin, A.; Reed, C.

    2012-12-01

    To protect the Earth from a hazardous asteroid impact, various mitigation methods have been proposed, including deflection of the asteroid by a spacecraft impact. AIDA, consisting of two mission elements, the Double Asteroid Redirection Test (DART) and the Asteroid Impact Monitoring (AIM) mission, is a demonstration of asteroid deflection. To date, there has been no such demonstration, and there is major uncertainty in the result of a spacecraft impact onto an asteroid, that is, the amount of deflection produced by a given momentum input from the impact. This uncertainty is in part due to unknown physical properties of the asteroid surface, such as porosity and strength, and in part due to poorly understood impact physics such that the momentum carried off by ejecta is highly uncertain. A first mission to demonstrate asteroid deflection would not only be a major step towards gaining the capability to mitigate an asteroid hazard, but in addition it would return unique information on an asteroid's strength, other surface properties, and internal structure. This information return would be highly relevant to future human exploration of asteroids. We report initial results of the AIDA joint mission concept study undertaken by the Johns Hopkins Applied Physics Laboratory and ESA with support from NASA centers including Goddard, Johnson and Jet Propulsion Laboratory. For AIDA, the DART spacecraft impactor study is coordinated with an ESA study of the AIM mission, which would rendezvous with the same asteroid to measure effects of the impact. Unlike the previous Don Quijote mission study performed by ESA in 2005-2007, DART envisions an impactor spacecraft to intercept the secondary member of a binary near-Earth asteroid. DART includes ground-based observations to measure the deflection independently of the rendezvous spacecraft observations from AIM, which also measures deflection and provides detailed characterization of the target asteroid. The joint mission AIDA

  18. ECONOMIC IMPACT OF CULTURAL TOURISM

    OpenAIRE

    Zrinka Zadel; Sinisa Bogdan

    2013-01-01

    The subject of analysis in the paper is economic impact of cultural tourism and identification of the main factors which directly affect cultural tourism revenues. Most countries do not have a statistical system of monitoring and analysing individual factors of cultural tourism such as the number of arrivals of cultural tourists and consumption of cultural tourists. Therefore, it is hard to assess the economic impact of cultural tourism. In cultural tourism, cultural assets are prepared and p...

  19. Impact cratering: A geologic process

    Science.gov (United States)

    Melosh, H. J.

    The mechanisms involved in the formation of impact craters are examined theoretically, reviewing the results of recent investigations. Topics addressed include crater morphology, stress waves in solids, the contact and compression stage, the excavation stage, and ejecta deposits. Consideration is given to the scaling of crater dimensions, the crater modification stage, multiring basins, cratered landscapes, atmospheric interactions, and the implications of impact cratering for planetary evolution. Extensive diagrams, graphs, tables, and images of typical craters are provided.

  20. Droplet impacts upon liquid surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ching, B.; Golay, M.W.; Johnson, T.J.

    1984-11-02

    The absorption and rebounding of single droplets and streams of droplets (of diameter less than 1200 micrometers) impacting upon the surface of a deep liquid were examined experimentally. Conservation of mechanical energy and momentum were used to explain rebounding droplet interactions, and impaction criteria have been established regarding the absorption of droplet streams. Surface tension is the dominant mechanism governing the observed behavior. Single droplets were never observed to rebound.

  1. The Deep Impact Experiment and the Physics of Impact Cratering

    Science.gov (United States)

    Richardson, J. E.; Melosh, H. J.; Deep Impact Science Team

    2005-08-01

    On July 4, 2005 the Deep Impact experiment produced an impact event on the surface of Comet 9P Tempel 1, using a 360 kg (primarily copper) impactor striking the comet at a velocity of 10.2 km/sec. In addition to images taken from the flyby spacecraft (500 km closest approach distance), images of the target were also returned from the impactor spacecraft, which show that the impactor hit the comet's surface at an oblique angle of roughly 60 degrees from the surface normal. The impactor struck the comet at an ideal location for viewing the cratering process by the flyby spacecraft both during the 800 second long post-impact imaging phase and during the ``look-back" imaging phase (beginning ˜ 45 minutes after impact). Within a fraction of a second of impact, an incandescent vapor plume emerged from the impact site, cooling rapidly and moving away from the comet at a speed of ˜ 5 km/sec. This vapor emission was followed by the emergence and rapid growth of a prominent, conical ejecta plume, indicating crater excavation flow. This ejecta plume was more opaque (composed of finer material) than predicted, obscuring clear observations of the impact crater itself (extraction efforts continue). However, the behavior of the plume during both it's growth and fallback stages is consistent with a gravity-scaled cratering event into a very weak (post-shock) target material. The expansion state of the plume during the look-back phase will also allow us to place constraints on the comet's gravity field (and by extension mass and density).

  2. 78 FR 14117 - Draft Environmental Impact Statement/Environmental Impact Report for Yolo Bypass Salmonid Habitat...

    Science.gov (United States)

    2013-03-04

    ... Bureau of Reclamation Draft Environmental Impact Statement/Environmental Impact Report for Yolo Bypass... Water Resources intend to prepare an environmental impact statement/ environmental impact report (EIS... addressed in the environmental impact statement/ environmental impact report: 1. March 14, 2013, 1:30-3:30...

  3. ECONOMIC IMPACT OF CULTURAL TOURISM

    Directory of Open Access Journals (Sweden)

    Zrinka Zadel

    2013-12-01

    Full Text Available The subject of analysis in the paper is economic impact of cultural tourism and identification of the main factors which directly affect cultural tourism revenues. Most countries do not have a statistical system of monitoring and analysing individual factors of cultural tourism such as the number of arrivals of cultural tourists and consumption of cultural tourists. Therefore, it is hard to assess the economic impact of cultural tourism. In cultural tourism, cultural assets are prepared and placed on the tourist market, i.e. cultural resources are transformed into cultural tourism products. The main objective is fulfilling tourists' needs, and achieving positive effects which includes economic effects. Identification of the economic impact of cultural tourism is important because cultural resources have an inestimable value for the local community. Tourism valorisation should be used in order to achieve the necessary maximum effects with minimum negative impacts which tourism may leave on cultural resources. The objective of the paper is to identify the economic contribution of cultural tourism in the Republic of Croatia and to propose a model of identification of economic impact of cultural tourism.

  4. Molecular dynamics simulation of impact test

    Energy Technology Data Exchange (ETDEWEB)

    Akahoshi, Y. [Kyushu Inst. of Tech., Kitakyushu, Fukuoka (Japan); Schmauder, S.; Ludwig, M. [Stuttgart Univ. (Germany). Staatliche Materialpruefungsanstalt

    1998-11-01

    This paper describes an impact test by molecular dynamics (MD) simulation to evaluate embrittlement of bcc Fe at different temperatures. A new impact test model is developed for MD simulation. The typical fracture behaviors show transition from brittle to ductile fracture, and a history of the impact loads also demonstrates its transition. We conclude that the impact test by MD could be feasible. (orig.)

  5. 77 FR 59397 - Economic Impact Policy

    Science.gov (United States)

    2012-09-27

    ... Doc No: 2012-23866] EXPORT-IMPORT BANK OF THE UNITED STATES Economic Impact Policy This notice is to... economic impact procedures. A draft of the proposed economic impact procedures can be accessed at the... email to economic.impact@exim.gov or by mail to 811 Vermont Avenue NW., Room 440, Washington, DC...

  6. Impact resistance of fiber composites

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1982-01-01

    Stress-strain curves are obtained for a variety of glass fiber and carbon fiber reinforced plastics in dynamic tension, over the stress-strain range of 0.00087-2070/sec. The test method is of the one-bar block-to-bar type, using a rotating disk or a pendulum as the loading apparatus and yielding accurate stress-strain curves up to the breaking strain. In the case of glass fiber reinforced plastic, the tensile strength, strain to peak impact stress, total strain and total absorbed energy all increase significantly as the strain rate increases. By contrast, carbon fiber reinforced plastics show lower rates of increase with strain rate. It is recommended that hybrid composites incorporating the high strength and rigidity of carbon fiber reinforced plastic with the high impact absorption of glass fiber reinforced plastics be developed for use in structures subjected to impact loading.

  7. SCIX IMPACT ON DWPF CPC

    Energy Technology Data Exchange (ETDEWEB)

    Koopman, D.

    2011-07-14

    A program was conducted to systematically evaluate potential impacts of the proposed Small Column Ion Exchange (SCIX) process on the Defense Waste Processing Facility (DWPF) Chemical Processing Cell (CPC). The program involved a series of interrelated tasks. Past studies of the impact of crystalline silicotitanate (CST) and monosodium titanate (MST) on DWPF were reviewed. Paper studies and material balance calculations were used to establish reasonable bounding levels of CST and MST in sludge. Following the paper studies, Sludge Batch 10 (SB10) simulant was modified to have both bounding and intermediate levels of MST and ground CST. The SCIX flow sheet includes grinding of the CST which is larger than DWPF frit when not ground. Nominal ground CST was not yet available, therefore a similar CST ground previously in Savannah River National Laboratory (SRNL) was used. It was believed that this CST was over ground and that it would bound the impact of nominal CST on sludge slurry properties. Lab-scale simulations of the DWPF CPC were conducted using SB10 simulants with no, intermediate, and bounding levels of CST and MST. Tests included both the Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) cycles. Simulations were performed at high and low acid stoichiometry. A demonstration of the extended CPC flowsheet was made that included streams from the site interim salt processing operations. A simulation using irradiated CST and MST was also completed. An extensive set of rheological measurements was made to search for potential adverse consequences of CST and MST and slurry rheology in the CPC. The SCIX CPC impact program was conducted in parallel with a program to evaluate the impact of SCIX on the final DWPF glass waste form and on the DWPF melter throughput. The studies must be considered together when evaluating the full impact of SCIX on DWPF. Due to the fact that the alternant flowsheet for DWPF has not been selected, this study did not

  8. Impact, productivity, and scientific excellence

    CERN Document Server

    Kaur, Jasleen; Menczer, Filippo; Flammini, Alessandro; Radicchi, Filippo

    2014-01-01

    Citation metrics are becoming pervasive in the quantitative evaluation of scholars, journals and institutions. More then ever before, hiring, promotion, and funding decisions rely on a variety of impact metrics that cannot disentangle quality from productivity, and are biased by factors such as discipline and academic age. Biases affecting the evaluation of single papers are compounded when one aggregates citation-based metrics across an entire publication record. It is not trivial to compare the quality of two scholars that during their careers have published at different rates in different disciplines in different periods of time. We propose a novel solution based on the generation of a statistical baseline specifically tailored on the academic profile of each researcher. By decoupling productivity and impact, our method can determine whether a certain level of impact can be explained by productivity alone, or additional ingredients of scientific excellence are necessary. The method is flexible enough to al...

  9. SEAFRAME. Stewardship of Facilities. Volume 2, Issue 3, 2006

    Science.gov (United States)

    2006-01-01

    or following seas at any angle. Tracks attached to the bottom of the bridge support a towing carriage that carries test personnel, instrumentation ... Charpy test machine for impact testing is being designed and installed in conjunction with Johns Hopkins University. Further expansion includes the...Dynamic Measurement Annex at West Bethesda, supports model testing with calibrated instruments and fabrication capabilities. Other assets include the

  10. Effect of small additional elements on DBTT of V 4Cr 4Ti irradiated at low temperatures

    Science.gov (United States)

    Shibayama, Tamaki; Yamagata, Ichiro; Kayano, Hideo; Namba, Chusei

    1998-10-01

    As a part of a program to screen several V-4Cr-4Ti containing Si, Al and Y alloys and optimize the amounts of Si, Al and Y, the Charpy impact test of five kinds of V-4Cr-4Ti-Si-Al-Y alloys by an instrumented Charpy impact testing machine using miniaturized specimens (1.5 mm × 1.5 mm × 20 mm) have been conducted before and after neutron irradiation. Charpy impact specimens were encapsulated in an aluminum vial filled with high purity He and irradiated up to 1.06 × 10 19 n/cm 2 ( E > 1 MeV, 156 h) at low temperatures (about 150°C) in Japan Materials Testing Reactor (JMTR). The ductile brittle transition temperature (DBTT) of each alloy was determined by various methods on absorbed energy, brittle fracture ratio and lateral expansion from a quantitative analysis of fractography for broken specimens after the Charpy impact test. Almost all specimens were embrittled after low temperature irradiation. Decomposition of primary precipitates could result in migration of interstitial elements to irradiation defects and many precipitates are formed under irradiation. Radiation hardening then caused the substantial degradation of its fracture toughness.

  11. Girth welding of X-60 pipeline with a 10kW laser

    Science.gov (United States)

    Megaw, J. H. P. C.; Hill, M.,; Osbourn, S. J.

    1986-10-01

    Single-pass autogeneous welding by 10kW laser of API 5LX X60 pipeline samples, of 760mm diameter and with wall thickness up to 19mm, in a configuration appropriate 4to J-lay operations, is described. The results of mechanical testing, including Charpy impact properties and their dependence on process conditions, are presented and discussed.

  12. Weldability investigation steel P 91 by weld thermal cycle simulation

    Directory of Open Access Journals (Sweden)

    M. Dunđer

    2015-07-01

    Full Text Available This paper elaborates results of hardness and impact energy of thermal cycle simulated specimens of high-alloy steel P 91 and their dependence on cooling time from 800 to 500 °C. Results were obtained by measuring hardness HV 1 and by experimental testing of Charpy notched specimens. Metallographic analysis of samples was performed on scanning electronic microscope.

  13. Lifetime environmental impact of buildings

    CERN Document Server

    Mequignon, Marc

    2014-01-01

    This work discusses the impact of the life of buildings on? sustainable development methods.?The study of the lifespan of the building is used to assess and?manage the environmental impacts associated?with all the stages of a product's life, from raw material extraction?through to repair, maintenance and?? 'end of life' scenarios. While several papers have discussed thegreenhouse gas emissions of buildings,?less research has been done on how these are affected by the lifespan?of the building. This book serves to?highlight the pertinence of this factor and contributes to providing?new ideas on

  14. Impact evaluation of infrastructure interventions

    DEFF Research Database (Denmark)

    Hansen, Henrik; Andersen, Ole Winckler; White, Howard

    2011-01-01

    The focus on results in development agencies has led to increased focus on impact evaluation to demonstrate the effectiveness of development programmes. A range of methods are available for counterfactual analysis of infrastructure interventions, as illustrated by the variety of papers in this vo......The focus on results in development agencies has led to increased focus on impact evaluation to demonstrate the effectiveness of development programmes. A range of methods are available for counterfactual analysis of infrastructure interventions, as illustrated by the variety of papers...

  15. Ejecta evolution during cone impact

    Science.gov (United States)

    Marston, Jeremy; Vakarelski, Ivan; Thoroddsen, Sigurdur

    2013-11-01

    We present results from an experimental study of the impact of conical shaped bodies into a pool of liquid. By varying the cone angle, impact speed and liquid physical properties, we examine a broad parameter space and seek to find conditions when self-similarity can be observed during this phenomena. We use high-speed imaging to capture the early-time motion of the liquid ejecta which emanates from the tip of the cone and travels up along the cone surface. Surprisingly, we find that the detachment of the ejecta can be simply described by air entrainment relationships derived from coating experiments.

  16. Introducing Life Cycle Impact Assessment

    DEFF Research Database (Denmark)

    Hauschild, Michael Zwicky; Huijbregts, Mark AJ

    2015-01-01

    This chapter serves as an introduction to the presentation of the many aspects of life cycle impact assessment (LCIA) in this volume of the book series ‘LCA Compendium’. It starts with a brief historical overview of the development of life cycle impact assessment driven by numerous national LCIA...... methodology projects and presents the international scientific discussions and methodological consensus attempts in consecutive working groups under the auspices of the Society of Environmental Toxicology and Chemistry (SETAC) as well as the UNEP/ SETAC Life Cycle Initiative, and the (almost) parallel...

  17. SPH Simulation of Hypervelocity Impacts

    Institute of Scientific and Technical Information of China (English)

    李金柱; 张庆明; 龙仁容

    2004-01-01

    The smooth particle hydrodynamics (SPH) method is a very important tool to resolve hypervelocity problems. The basic principle of SPH method and how to generate a proper SPH mesh is described. The results of SPH simulations of hypervelocity impacts on thin or thick aluminum plates, performed by using the LS-DYNA 3D computer code, are also reported. The forming process and composition of the debris clouds simulated are identical with the experiment results. It can be concluded that the simulation is reasonable and SPH method is an ideal method for hypervelocity impact simulation.

  18. The Selby Coalfield impact study

    Energy Technology Data Exchange (ETDEWEB)

    Shutt, J.; Henderson, R.; Kumi-Ampofo, F.; Thursfield, D. [Leeds Metropolitan University, Leeds (United Kingdom). Leeds Business School

    2002-07-01

    This report considers the likely economic and social impacts. It sets out proposals for the establishment of a Selby Mines Closure Task Force. There is a need to mitigate the economic and social impacts of the potential closure and to develop a re-invigorated focus on a sub-regional skills, re-training and regeneration and planning programme co-ordinating the wide range of stakeholders who will need to be involved. 26 refs., 4 figs., 15 tabs. 12 maps., 9 apps.

  19. Rare earth magnets and impaction.

    Science.gov (United States)

    Vardimon, A D; Graber, T M; Drescher, D; Bourauel, C

    1991-12-01

    Aberration in the eruption process was found to be a prime etiologic factor in inducing impaction. Thus an ideal treatment approach should attempt to mimic the normal eruption modus. However, conventional traction methods have been found to be associated with gingiva inflammation, bone recession, reduced attached gingiva, periodontal pockets, exposed cementoenamel junction, and root resorption of the impacted and adjacent teeth. These side effects are the result of premature exposure of the impacted tooth to the oral cavity through a nonself-cleansing pathway and an uncontrolled force system. The present study introduces a new, magnetic attraction system, with a magnetic bracket bonded to an impacted tooth and an intraoral magnet linked to a Hawley type retainer. Vertical and horizontal magnetic brackets were designed, with the magnetic axis magnetized parallel and perpendicular to the base of the bracket, respectively. The vertical type is used for impacted incisors and canines, and the horizontal magnetic bracket is applied for impacted premolars and molars. A three-dimensional analysis of the magnetic force system, by means of the OMSS apparatus, found the small magnetic bracket combined with a large pole surface area of the intraoral magnet to exhibit the most efficient convergent guidance. For this report the magnetic eruption device was examined on one animal subject and four patients. The Nd2Fe14B magnets were coated with parylene and/or encapsulated in stainless steel housings. In deep impaction, the magnetic bracket was cold-sterilized before surgery, and the surgical mucoperiosteal flap was then sutured over the bonded magnetic bracket. Attraction was initiated 1 to 2 weeks after healing. Thus tooth emergence into the oral cavity replicated normal eruption conditioning. The system operated at an attractive force level of 0.2 to 0.5 N. Adjustment was accomplished by temporarily interposing a magnetic spacer between the two magnetic units. No side effects

  20. Large meteoroid's impact damage: review of available impact hazard simulators

    Science.gov (United States)

    Moreno-Ibáñez, M.; Gritsevich, M.; Trigo-Rodríguez, J. M.

    2016-01-01

    The damage caused by meter-sized meteoroids encountering the Earth is expected to be severe. Meteor-sized objects in heliocentric orbits can release energies higher than 108 J either in the upper atmosphere through an energetic airblast or, if reaching the surface, their impact may create a crater, provoke an earthquake or start up a tsunami. A limited variety of cases has been observed in the recent past (e.g. Tunguska, Carancas or Chelyabinsk). Hence, our knowledge has to be constrained with the help of theoretical studies and numerical simulations. There are several simulation programs which aim to forecast the impact consequences of such events. We have tested them using the recent case of the Chelyabinsk superbolide. Particularly, Chelyabinsk belongs to the ten to hundred meter-sized objects which constitute the main source of risk to Earth given the current difficulty in detecting them in advance. Furthermore, it was a detailed documented case, thus allowing us to properly check the accuracy of the studied simulators. As we present, these open simulators provide a first approximation of the impact consequences. However, all of them fail to accurately determine the caused damage. We explain the observed discrepancies between the observed and simulated consequences with the following consideration. The large amount of unknown properties of the potential impacting meteoroid, the atmospheric conditions, the flight dynamics and the uncertainty in the impact point itself hinder any modelling task. This difficulty can be partially overcome by reducing the number of unknowns using dimensional analysis and scaling laws. Despite the description of physical processes associated with atmospheric entry could be still further improved, we conclude that such approach would significantly improve the efficiency of the simulators.

  1. 低C含Cu NV-F690特厚钢板的精细组织和强韧性%FINE MICROSTRUCTURE AND TOUGHNESS OF LOW CARBON COPPER CONTAINING ULTRA HIGH STRENGTH NV-F690 HEAVY STEEL PLATE

    Institute of Scientific and Technical Information of China (English)

    刘东升; 程丙贵; 陈圆圆

    2012-01-01

    本文通过板坯连铸、钢板控轧控冷(TMCP)、固溶淬火回火(QT)工业生产流程,开发低C含Cu高强韧NV-F690特厚(厚度t为80 mm)船体和海洋平台用钢板,使用SEM,EBSD和TEM分别研究了淬火(Q)态和QT态钢板的精细组织,测试了距离钢板表面t/4处(高冷却速率)和芯部t/2处(低冷却速率)的室温硬度和拉伸性能,在-60和-80℃下进行了Charpy冲击(Charpy V notch,CVN)示波实验.结果表明,淬火速率较大有利于板条组织形成和提高大角度晶界比例,t/4处的组织为板条状贝氏体(LB),板条间存在细小片状马氏体/奥氏体(M/A)组元,晶粒间大角度晶界(>15°)体积分数为67.5%;t/2处的组织为粒状贝氏体(GB)+LB.大角度晶界体积分数为63.0%;Q态下的LB具有高位错密度,但晶粒内不存在Cu析出相.经过650℃回火150 min,钢板的强韧性匹配优良,低温下呈韧性断裂,大量含Cu弥散沉淀相在基体组织内析出.t/2处的M/A组元分解为Cr-Mo碳化物,贝氏体板条宽度为0.4 μm,大角度晶界分数为62.5%; t/4处的LB板条回复,板条内存在与基体取向差较大的亚晶,大角度晶界分数提高到71.7%,板条平均宽度为0.2 μm.在-80℃下,NV-F690钢板t/4处的韧性高于t/2处的韧性.随着纤维断裂位移的增大,韧窝断裂区比例和韧窝尺寸逐渐增大,NV-F690钢低温Charpy冲击能量逐渐提高.%Advanced NV-F690 heavy steel plates for offshore structure and shipbuilding have been produced via continuous casting of the slab, thermomechanical control rolling of the plate followed by solutionizing (austenitizing), quenching and tempering (QT) steps. The present work is to reveal the microstructure evolution and evaluate the mechanical properties of 80 mm thick plates subjected to the QT process. The microstructures were characterized with SEM, EBSD and TEM. At quarter thickness (f/4) where the cooling rate was rapid, the as quenched microstructures consist of mainly lath

  2. Mechanical vs. informational components of price impact

    Science.gov (United States)

    Doyne Farmer, J.; Zamani, N.

    2007-01-01

    We study the problem of what causes prices to change. It is well known that trading impacts prices — orders to buy drive the price up, and orders to sell drive it down. We introduce a means of decomposing the total impact of trading into two components, defining the mechanical impact of a trading order as the change in future prices in the absence of any future changes in decision making, and the informational impact as the remainder of the total impact once mechanical impact is removed. This decomposition is performed using order book data from the London Stock Exchange. The average mechanical impact of a market order decays to zero as a function of time, at an asymptotic rate that is consistent with a power law with an exponent of roughly 1.7. In contrast the average informational impact builds to approach a constant value. Initially the impact is entirely mechanical, and is about half as big as the asymptotic informational impact. The size of the informational impact is positively correlated to mechanical impact. For cases where the mechanical impact is zero for all times, we find that the informational impact is negative, i.e. buy market orders that have no mechanical impact at all generate strong negative price responses.

  3. A Scale of Mobbing Impacts

    Science.gov (United States)

    Yaman, Erkan

    2012-01-01

    The aim of this research was to develop the Mobbing Impacts Scale and to examine its validity and reliability analyses. The sample of study consisted of 509 teachers from Sakarya. In this study construct validity, internal consistency, test-retest reliabilities and item analysis of the scale were examined. As a result of factor analysis for…

  4. Employment Impact of Electronic Business.

    Science.gov (United States)

    Hecker, Daniel E.

    2001-01-01

    Electronic business is stimulating employment in some sectors across industries, such as computer-related and customer service occupations, and diminishing employment in others, such as administrative support and marketing/sales. Similarly, employment impacts will vary by industry. (Contains 56 notes and references.) (SK)

  5. Drop Impact on Superheated Surfaces

    NARCIS (Netherlands)

    Tran, A.T.; Staat, H.J.J.; Prosperetti, A.; Sun, C.; Lohse, D.

    2012-01-01

    At the impact of a liquid droplet on a smooth surface heated above the liquid’s boiling point, the droplet either immediately boils when it contacts the surface (“contact boiling”), or without any surface contact forms a Leidenfrost vapor layer towards the hot surface and bounces back (“gentle film

  6. Clinical Impact of Vaccine Development.

    Science.gov (United States)

    Nambiar, Puja H; Daza, Alejandro Delgado; Livornese, Lawrence L

    2016-01-01

    The discovery and development of immunization has been a singular improvement in the health of mankind. This chapter reviews currently available vaccines, their historical development, and impact on public health. Specific mention is made in regard to the challenges and pursuit of a vaccine for the human immunodeficiency virus as well as the unfounded link between autism and measles vaccination.

  7. Collocation Impact on Team Effectiveness

    Directory of Open Access Journals (Sweden)

    M Eccles

    2010-11-01

    Full Text Available The collocation of software development teams is common, specially in agile software development environments. However little is known about the impact of collocation on the team’s effectiveness. This paper explores the impact of collocating agile software development teams on a number of team effectiveness factors. The study focused on South African software development teams and gathered data through the use of questionnaires and interviews. The key finding was that collocation has a positive impact on a number of team effectiveness factors which can be categorised under team composition, team support, team management and structure and team communication. Some of the negative impact collocation had on team effectiveness relate to the fact that team members perceived that less emphasis was placed on roles, that morale of the group was influenced by individuals, and that collocation was invasive, reduced level of privacy and increased frequency of interruptions. Overall through it is proposed that companies should consider collocating their agile software development teams, as collocation might leverage overall team effectiveness.

  8. Elastodynamic Impact into Piezoelectric Media

    Science.gov (United States)

    2014-09-01

    boundary condition to the problem of elastodynamic impact into a lead zirconate titanate (PZT-4) target and find that the solutions obtained using... titanate (PZT-4) target are compared with solutions obtained using a finite-difference time-domain (FDTD) code and the commercial finite element (FE

  9. Health Impact Statement Schiphol Airport

    NARCIS (Netherlands)

    Staatsen BAM; Franssen EAM; Lebret E; CCM

    1994-01-01

    In this report an assessment has been made of the effects on public health caused by environmental pollution originating from activities around Schiphol airport. This investigation is part of an integral Environmental Impact Assessment that was legally required for the planned expansion of the airp

  10. Agroecosystem Impacts on Water Quality

    Science.gov (United States)

    Reedy, R. C.; Scanlon, B. R.

    2010-12-01

    Agroecosystems can have large scale impacts on soil water and groundwater quality by mobilizing salts into underlying aquifers through enhanced recharge and increasing chemical loading to systems through fertilizer applications and irrigation water. Crop evapotranspiration is similar to desalinization in that root-water uptake excludes most salts, and soil-water salinity levels may build up when water drainage or percolation through the root zone is insufficient to flush accumulated salts. The objective of this study was to evaluate impacts of agroecosystems on soil water and groundwater quality using data from the US High Plains and California Central Valley. Natural ecosystems accumulated large reservoirs of salts in unsaturated soils in the southern High Plains and southern part of the Central Valley. Increased recharge under rainfed and irrigated agriculture mobilized these salt reservoirs into the underlying aquifer in the southern High Plains, increasing groundwater salinity, particularly chloride and sulfate. Deficit irrigation in the southern High Plains has created large salt bulges in the unsaturated zone because of insufficient irrigation to flush these salts into the underlying aquifer. Irrigation in both the High Plains and Central Valley regions has markedly increased groundwater nitrate levels, particularly in irrigated areas because of higher fertilizer applications. Agroecosystem impacts on water quality reflect a delicate balance between water and salt cycles and crop production should be managed to minimize negative environmental impacts.

  11. CEO Narcissism: Measurement and Impact

    NARCIS (Netherlands)

    J.A. Rijsenbilt (Antoinette)

    2011-01-01

    textabstractThis research describes the objective measurement of CEO narcissism and its impact on organizational outcomes. Narcissism forms an essential element for effective leadership and is as such an important personal characteristic for CEOs. CEO narcissism can be measured by investigating fi

  12. Nickel: Impact on horticultural characteristics

    Science.gov (United States)

    Knowledge by practitioners regarding the potential impact of nickel nutritional physiology on pecan orchard profitability is a limiting factor in optimization of physiological efficiency of orchard enterprises. Knowledge by farmers and extension specialists about the role of nickel, a newly recogni...

  13. Glatz Prototype Seat Impact Testing

    Science.gov (United States)

    2013-07-03

    thrust piston, the sled coasts to a stop or is stopped with a triggered pneumatic brake system. The impact acceleration is roughly sinusoidal. HIA...all PH testing. The HIA consists of a 4 ft by 8 ft sled positioned on a 204 ft long track and is accelerated using a 24 inch diameter pneumatic

  14. Economic impact of GM crops

    Science.gov (United States)

    Brookes, Graham; Barfoot, Peter

    2014-01-01

    A key part of any assessment of the global value of crop biotechnology in agriculture is an examination of its economic impact at the farm level. This paper follows earlier annual studies which examined economic impacts on yields, key costs of production, direct farm income and effects, and impacts on the production base of the four main crops of soybeans, corn, cotton and canola. The commercialization of genetically modified (GM) crops has continued to occur at a rapid rate, with important changes in both the overall level of adoption and impact occurring in 2012. This annual updated analysis shows that there have been very significant net economic benefits at the farm level amounting to $18.8 billion in 2012 and $116.6 billion for the 17-year period (in nominal terms). These economic gains have been divided roughly 50% each to farmers in developed and developing countries. GM technology have also made important contributions to increasing global production levels of the four main crops, having added 122 million tonnes and 230 million tonnes respectively, to the global production of soybeans and maize since the introduction of the technology in the mid-1990s. PMID:24637520

  15. Review of submissions: competition impacts

    NARCIS (Netherlands)

    G. Burghouwt; W. de Wit

    2015-01-01

    The Airports Commission requested ITF/SEO to provide technical assistance with analysing responses that pertain to the previous work undertaken by the ITF/SEO. This report assesses the submissions by the stakeholders in relation to competition impacts and compares them with the ITF/SEO results and t

  16. Aluminum honeycomb impact limiter study

    Energy Technology Data Exchange (ETDEWEB)

    Yaksh, M.C.; Thompson, T.C. (Nuclear Assurance Corp., Norcross, GA (United States)); Nickell, R.E. (Applied Science and Technology, Inc., Poway, CA (United States))

    1991-07-01

    Design requirements for a cask transporting radioactive materials must include the condition of the 30-foot free fall of the cask onto an unyielding surface. To reduce the deceleration loads to a tolerable level for all the components of the cask, a component (impact limiter) is designed to absorb the kinetic energy. The material, shape, and method of attachment of the impact limiter to the cask body comprises the design of the impact limiter. The impact limiter material of interest is honeycomb aluminum, and the particular design examined was for the NAC Legal Weight Truck cask (NAC-LWT) for spent fuel from light water reactors. The NAC-LWT has a design weight of 52,000 pounds, and it has a nominal length of 200 inches. The report describes the numerical calculations embodied in the FADE program to determine the accelerations and crush strain resulting from an arbitrary height and angle of orientation. Since the program serves as a design tool, static tests are performed to assess the effect of the shell containing the honeycomb aluminum. The static tests and their results are contained in the study. The static tests are used to demonstrate for licensing purposes the level of accelerations imposed on the cask during a 30-foot drop. 3 refs., 41 figs., 15 tabs.

  17. Health in social impact assessment

    NARCIS (Netherlands)

    den Broeder, Lea; Vanclay, Frank; Fehr, Rainer; Viliani, Francesca; Nowacki, Julia; Martuzzi, Marco

    2014-01-01

    SIA developed alongside EIA in the early 1970s as a mechanism to consider the social impacts of planned interventions. The early understanding tended to limit the practical application of SIA to the project level, usually within the context of regulatory frameworks, and primarily considered only the

  18. Interactive modeling of storm impact

    Science.gov (United States)

    van Rooijen, A.; Baart, F.; Roelvink, J. A.; Donchyts, G.; Scheel, F.; de Boer, W.

    2014-12-01

    In the past decades the impact of storms on the coastal zone has increasingly drawn the attention of policy makers and coastal planners, engineers and researchers. The mean reason for this interest is the high density of the world's population living near the ocean, in combination with climate change. Due to sea level rise and extremer weather conditions, many of the world's coastlines are becoming more vulnerable to the potential of flooding. Currently it is common practice to predict storm impact using physics-based numerical models. The numerical model utilizes several inputs (e.g. bathymetry, waves, surge) to calculate the impact on the coastline. Traditionally, the numerical modeller takes the following three steps: schematization/model setup, running and post-processing. This process generally has a total feedback time in the order of hours to days, and is suitable for so-called confirmatory modelling.However, often models are applied as an exploratory tool, in which the effect of e.g. different hydraulic conditions, or measures is investigated. The above described traditional work flow is not the most efficient method for exploratory modelling. Interactive modelling lets users adjust a simulation while running. For models typically used for storm impact studies (e.g. XBeach, Delft3D, D-Flow FM), the user can for instance change the storm surge level, wave conditions, or add a measure such as a nourishment or a seawall. The model will take the adjustments into account immediately, and will directly compute the effect. Using this method, tools can be developed in which stakeholders (e.g. coastal planners, policy makers) are in control and together evaluate ideas by interacting with the model. Here we will show initial results for interactive modelling with a storm impact model.

  19. [The "impact factor" and the impact of medical journals].

    Science.gov (United States)

    Reyes, H

    1998-02-01

    Original articles published in scientific journals are important parameters for committees when they evaluate academic promotions or research grant applications. The analysis usually tries to give each paper a qualitative/quantitative assessment. An article's citation by others is accepted as a fair estimate of the value assigned to its originality and importance. A main determinant of every citation index is the international relevance attained by the journal where the article appeared. The "impact factor" of journals enlisted in the mainstream literature, as defined by the Journal Citation Reports (ISI), is being used by many assessors worldwide. But this index appears to be an unfair unit of measurement for journals that, although included in the main international data bases, are published in non-English languages. Furthermore, some local journals that are not enlisted by the Institute for Scientific Information apply external peer review to select their publications. In contrast, those same journals may have great relevance for their contributing authors and a high impact in their readers. The Editor's proposal is to classify original articles published in biomedical sciences, clinical medicine and public health topics using a three steps scale: a low score to articles published in local journals that use the peer review system, even though they were not enlisted in international data bases; a higher score to articles published in journals included in the mainstream literature, without considering their "impact factors" as differential values; and the highest score to articles published in journals recognized as international leaders in biomedicine, general medicine or in the subspecialties. Therefore, mainstream journals published in non-English languages would not be discriminated from other journals having higher "impact factors" mainly due to their use of the English language.

  20. Calculating Minimum Detectable Impacts in Teen Pregnancy Prevention Impact Evaluations

    OpenAIRE

    Lorenzo Moreno; Russell Cole

    2014-01-01

    This brief provides an overview of how researchers can calculate the minimum detectable impacts (MDIs), which are related to power calculations, for Teen Pregnancy Prevention (TPP) evaluations. It describes a tool that evaluators can use for their own MDI calculations, and includes examples that highlight how to use the tool. A technical appendix provides more details on the formulae in the tool that inform MDI calculations.

  1. Effect of Oxygen Content Upon the Microstructural and Mechanical Properties of Type 316L Austenitic Stainless Steel Manufactured by Hot Isostatic Pressing

    Science.gov (United States)

    Cooper, Adam J.; Cooper, Norman I.; Dhers, Jean; Sherry, Andrew H.

    2016-09-01

    Although hot isostatic pressing (HIP) has been shown to demonstrate significant advances over more conventional manufacture routes, it is important to appreciate and quantify the detrimental effects of oxygen involvement during the HIP manufacture process on the microstructural and material properties of the resulting component. This paper quantifies the effects of oxygen content on the microstructure and Charpy impact properties of HIP'd austenitic stainless steel, through combination of detailed metallographic examination and mechanical testing on HIP'd Type 316L steel containing different concentrations (100 to 190 ppm) of oxygen. Micron-scale pores were visible in the microstructure of the HIP'd materials postmetallographic preparation, which result from the removal of nonmetallic oxide inclusions during metallographic preparation. The area fraction of the resulting pores is shown to correlate with the oxygen concentration which influences the Charpy impact toughness over the temperature range of 77 K to 573 K (-196 °C to 300 °C), and demonstrates the influence of oxygen involved during the HIP manufacture process on Charpy toughness. The same test procedures and microstructural analyses were performed on commercially available forged 316L. This showed comparatively fewer inclusions and exhibited higher Charpy impact toughness over the tested temperature range.

  2. Oceanic Impact: Mechanisms and Environmental Perturbations

    Science.gov (United States)

    Gersonde, Rainer (Editor); Deutsch, Alex (Editor); Ivanov, Boris A. (Editor); Kyte, Frank T. (Editor)

    2002-01-01

    The contents include the following: Oceanic impacts-a growing field of fundamental geoscience. Shock metamorphism on the ocean floor (numerical simulations). Numerical modeling of impact-induced modifications of the deep-sea floor. Computer modelling of the water resurge at a marine impact: the Lockne crater, Sweden. Experimental investigation of the role of water in impact vaporization chemistry. Calcareous plankton stratigraphy around the Pliocene Eltanin asteroid impact area (SE Pacific): documentation and application for geological and paleoceanographic reconstruction. Composition of impact melt debris from the Eltanin impact strewn field, Bellingshausen Sea. Iridium concentrations and abundances of meteoritic ejecta from the Eltanin impact in sediment cores from Polarstern expedition ANT XII/4. Unmelted meteoritic debris collected from Eltanin ejecta in Polarstern cores from expedition ANT XII/4. Impact tsunami-Eltanin. Ancient impact structures on modern continental shelves: The Chesapeake Bay, Montagnais, and Toms Canyon craters, Atlantic margin of North America. The Mjolnir marine impact crater porosity anomaly. Kardla (Hiiu-maa Island, Estonia) - the buried and well-preserved Ordovician marine impact structure. Long-term effect of the Kardla crater (Hiiu-maa, Estonia) on Late Ordovician carbonate sedimentation. The middle Devonian Kaluga impact crater (Russia): new interpretation of marine setting.

  3. Mechanical vs. informational components of price impact

    CERN Document Server

    Farmer, J D; Zamani, Neda

    2006-01-01

    We study the problem of what causes prices to change. We define the mechanical impact of a trading order as the change in future prices in the absence of any future changes in decision making, and its it informational impact as the remainder of the total impact once mechanical impact is removed. We introduce a method of measuring mechanical impact and apply it to order book data from the London Stock Exchange. The average mechanical impact of a market order decays to zero as a function of time, at an asymptotic rate that is consistent with a power law with an exponent of roughly 1.7. In contrast the average informational impact builds to approach a constant value. Initially the impact is entirely mechanical, and is about half as big as the asymptotic informational impact. The size of the informational impact is positively correlated to mechanical impact. For cases where the mechanical impact is zero for all times, we find that the informational impact is negative, i.e. buy market orders that have no mechanica...

  4. Assessment of Traffic Noise Impacts

    DEFF Research Database (Denmark)

    Rich, Jeppe Husted; Nielsen, Otto Anker

    2004-01-01

    A steady growth in traffic intensities in most urban areas throughout the world has forced planners and politicians to seriously consider the resulting environmental impact, such as traffic noise, accidents and air pollution. The assessment of such negative factors is needed in order to reveal...... the true social benefit of infrastructure plans. The paper presents a noise assessment model for the Copenhagen region, which brings together GIS technology and non-linear hedonic regression models to reveal the implicit costs of traffic noise measured as the marginal percentage loss in property values...... with respect to the decibel traffic noise. The model distinguishes between houses and apartments and shows that the ability to include refined accessibility variables have significant impact on estimated prices....

  5. Atomic Ionization by Electron Impact

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The field of atomic ionization by electron impact is several decades old. In that period of time, significant progress has been made in several aspects of the problem and we have learned a lot about ionizing collisions as a result of this work. Over the years, both the experiments and theories have improved dramatically. Experiments are now able to measure absolute triple differential cross sections for both in-plane or out-of-plane geometries. Theories have been getting better and better at including all the 3-body interactions in the wavefunction for the system. However, during the history of the field, experiment has been ahead of theory and it is just very recently that theory has started to catch up. In this paper, we will show that theory is now able to accurately predict the results of electron impact ionization of hydrogen for intermediate and higher energies.

  6. Impact of Emotion on Consciousness

    DEFF Research Database (Denmark)

    Thomsen, Kristine Rømer; Lou, Hans Olav Christensen; Jønsson, Morten;

    2011-01-01

    Emotion and reward have been proposed to be closely linked to conscious experience, but empirical data are lacking. The anterior cingulate cortex (ACC) plays a central role in the hedonic dimension of conscious experience; thus potentially a key region in interactions between emotion...... and consciousness. Here we tested the impact of emotion on conscious experience, and directly investigated the role of the ACC. We used a masked paradigm that measures conscious reportability in terms of subjective confidence and objective accuracy in identifying the briefly presented stimulus in a forced......-choice test. By manipulating the emotional valence (positive, neutral, negative) and the presentation time (16 ms, 32 ms, 80 ms) we measured the impact of these variables on conscious and subliminal (i.e. below threshold) processing. First, we tested normal participants using face and word stimuli. Results...

  7. Water impacting on superhydrophobic macrotextures.

    Science.gov (United States)

    Gauthier, Anaïs; Symon, Sean; Clanet, Christophe; Quéré, David

    2015-08-11

    It has been recently shown that the presence of macrotextures on superhydrophobic materials can markedly modify the dynamics of water impacting them, and in particular significantly reduce the contact time of bouncing drops, compared with what is observed on a flat surface. This finding constitutes a significant step in the maximization of water repellency, since it enables to minimize even further the contact between solid and liquid. It also opens a new axis of research on the design of super-structures to induce specific functions such as anti-freezing, liquid fragmentation and/or recomposition, guiding, trapping and so on. Here we show that the contact time of drops bouncing on a repellent macrotexture takes discrete values when varying the impact speed. This allows us to propose a quantitative analysis of the reduction of contact time and thus to understand how and why macrotextures can control the dynamical properties of bouncing drops.

  8. Capturing the impact of software

    Science.gov (United States)

    Piwowar, Heather

    2017-01-01

    Research software is undervalued in funding and tenure decisions because its impact is poorly evaluated within the traditional paper-based ecosystem. The talk presents the NSF-funded Depsy project (http://depsy.org) -- a proof-of-concept system designed to address this problem by tracking the impact of software in software-native ways. Depsy finds mentions of software itself in the literature, rather than just counting citations to a wrapper paper about the software. It discovers how software gets reused by other software, even when it's not cited at all. And finally Depsy attempts to represent the full complexity of software authorship, where one project can involve hundreds of contributors in multiple roles that don't map to traditional paper authorship.

  9. BPMN Impact on Process Modeling

    OpenAIRE

    Polak, Przemyslaw

    2013-01-01

    Recent years have seen huge rise in popularity of BPMN in the area of business process modeling, especially among business analysts. This notation has characteristics that distinguish it significantly from the previously popular process modeling notations, such as EPC. The article contains the analysis of some important characteristics of BPMN and provides author’s conclusions on the impact that the popularity and specificity of BPMN can have on the practice of process modeling. Author's obse...

  10. Soft Skills for Hard Impact

    Science.gov (United States)

    Grigorov, Ivo; Davidson, Joy; Knoth, Petr; Kuchma, Iryna; Schmidt, Birgit; Rettberg, Najla; Rogrigues, Eloy

    2015-04-01

    Marine and Earth Science graduates will be under increasing pressure in future to delve into research questions of relevance to societal challenges. Even fundamental research focused on basic processes of the environment and universe will in the coming decade need to justify their societal impact. As the Research Excellence Frameworks (REF) for research evaluation shift more and more away from the classical Impact Factor and number of peer-reviewed publications to "societal impact", the question remains whether the current graduates, and future researchers, are sufficiently prepared to deal with this reality. The essential compliment of skills beyond research excellence, rigor and method are traditionally described as "soft skills". This includes how to formulate an argument, how to construct a scientific publication, how to communicate such publications to non-experts, place them in context of societal challenges and relevant policies, how to write a competitive proposal and "market" one's research idea to build a research group around an interesting research topic. Such "soft skills" can produce very measurable and concrete impact for career development, but are rarely provided systematically and coherently by graduate schools in general. The presentation will focus on Open Science as a set of "soft skills", and demonstrate why graduate schools should train Open Science competencies alongside research excellence by default. Open Science is about removing all barriers to research process and outputs, both published and unpublished, and directly supports transparency and reproducibility of the research process. Open Science as a set of news competencies can also foster unexpected collaborations, engage citizen scientists into co-creation of solutions to societal challenges, as well as use concepts of Open Science to transfer new knowledge to the knowledge-based private sector, and help them with formulating more competitive research proposals in future.

  11. Impact origin of the Moon

    Energy Technology Data Exchange (ETDEWEB)

    Slattery, W.L.

    1998-12-31

    A few years after the Apollo flights to the Moon, it became clear that all of the existing theories on the origin of the Moon would not satisfy the growing body of constraints which appeared with the data gathered by the Apollo flights. About the same time, researchers began to realize that the inner (terrestrial) planets were not born quietly -- all had evidences of impacts on their surfaces. This fact reinforced the idea that the planets had formed by the accumulation of planetesimals. Since the Earth`s moon is unique among the terrestrial planets, a few researchers realized that perhaps the Moon originated in a singular event; an event that was quite probable, but not so probable that one would expect all the terrestrial planets to have a large moon. And thus was born the idea that a giant impact formed the Moon. Impacts would be common in the early solar system; perhaps a really large impact of two almost fully formed planets of disparate sizes would lead to material orbiting the proto-earth, a proto-moon. This idea remained to be tested. Using a relatively new, but robust, method of doing the hydrodynamics of the collision (Smoothed-Particle Hydrodynamics), the author and his colleagues (W. Benz, Univ. of Arizona, and A.G.W. Cameron, Harvard College Obs.) did a large number of collision simulations on a supercomputer. The author found two major scenarios which would result in the formation of the Moon. The first was direct formation; a moon-sized object is boosted into orbit by gravitational torques. The second is when the orbiting material forms a disk, which, with subsequent evolution can form the Moon. In either case the physical and chemical properties of the newly formed Moon would very neatly satisfy the physical and chemical constraints of the current Moon. Also, in both scenarios the surface of the Earth would be quite hot after the collision. This aspect remains to be explored.

  12. Programmatic Impact of SDRAM SEFI

    Science.gov (United States)

    Guertin, Steven M.; Allen, Gregory R.; Sheldon, Douglas J.

    2012-01-01

    The Elpida EDS5104(08)ABTA 512Mb SDRAM is examined for programmatic impact of SEE. Use cases for the devices including EDAC and mode register reload are examined. Results indicate some SEE mitigation methods require careful application to achieve system-level benefits, while some event types are essentially mitigated by the application use. In the studied devices MBE and SEFI are identified and investigated as mechanisms requiring special consideration.

  13. Psychosocial impact of hidradenitis suppurativa

    DEFF Research Database (Denmark)

    Esmann, S.; Jemec, G.B.E.

    2011-01-01

    , especially in relation to smell and appearance, various emotional reactions, and feelings of lack of control. It was found that hidra-denitis suppurativa has a great emotional impact on patients and promotes isolation due to fear of stigmati-zation. Shame and irritation are frequent and relate to smell......, scars, itching and pain. Quality of life is adversely affected and professional support is needed.© 2011 The Authors....

  14. The meteorite impact-induced tsunami hazard.

    Science.gov (United States)

    Wünnemann, K; Weiss, R

    2015-10-28

    When a cosmic object strikes the Earth, it most probably falls into an ocean. Depending on the impact energy and the depth of the ocean, a large amount of water is displaced, forming a temporary crater in the water column. Large tsunami-like waves originate from the collapse of the cavity in the water and the ejecta splash. Because of the far-reaching destructive consequences of such waves, an oceanic impact has been suggested to be more severe than a similar-sized impact on land; in other words, oceanic impacts may punch over their weight. This review paper summarizes the process of impact-induced wave generation and subsequent propagation, whether the wave characteristic differs from tsunamis generated by other classical mechanisms, and what methods have been applied to quantify the consequences of an oceanic impact. Finally, the impact-induced tsunami hazard will be evaluated by means of the Eltanin impact event.

  15. "Impact 4" Berliinis ja Poznanis / Vappu Thurlow

    Index Scriptorium Estoniae

    Thurlow, Vappu, 1960-

    2005-01-01

    5.-10. IX Berliinis ja Poznanis toimunud neljandast rahvusvahelisest graafikakonverentsist "Impact" alapealkirjaga "Kontakt". Eestist osalesid Loit Jõekalda, Eve Kask, Karin Laansoo ja Vappu Thurlow. 2007. a. Tallinnas toimuva "Impact 5", alapealkirjaga "Slices of Time/Lõigutud aeg", kontseptsioon

  16. Impact microcraters on an Australasian microtektite

    Digital Repository Service at National Institute of Oceanography (India)

    ShyamPrasad, M.; Sudhakar, M.

    has a welded promontory, is unique. The projectiles that produced the impacts defined varying trajectories and velocities, ranging from hypervelocity to low velocity (a few 10 m/s). The impacts took place while the microtektite was in flight...

  17. Effects of the neutronic irradiation on the impact tests. Efectos de la irradiacion neutronica sobre los ensayos de resiliencia

    Energy Technology Data Exchange (ETDEWEB)

    Lapea, J.; Perosanz, F.J.; Hernandez, M.T.

    1993-01-01

    The changes that the Charpy curves suffer when steel is exposed to neutronic fluence are studied. Three steels with different chemical composition were chosen, two of them (JPF and JPJ) being treated at only one neutronic fluence, while the last one (JRQ) was irradiated at three fluences. In this way, it was possible to compare the effect of increasing the neutronic dose, and to study the experimental results as a function of the steel chemical composition. Two characteristic facts have been observed: the displacement of the curve at higher temperatures, and decrease of the upper shelf energy (USE). The mechanical recovery of the materials after two different thermal treatments is also described, and a comparation between the experimental results obtained and the damage prediction formulas given by different regulatory international organisms in the nuclear field is established. Author. 11 refs.

  18. Tensile and impact properties of vanadium-base alloys irradiated at low temperatures in the ATR-A1 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, H.; Nowicki, L.J.; Billone, M.C.; Chung, H.M.; Smith, D.L. [Argonne National Lab., IL (United States)

    1998-03-01

    Subsize tensile and Charpy specimens made from several V-(4-5)Cr-(4-5)Ti alloys were irradiated in the ATR-A1 experiment to study the effects of low-temperature irradiation on mechanical properties. These specimens were contained in lithium-bonded subcapsules and irradiated at temperatures between {approx}200 and 300 C. Peak neutron damage was {approx}4.7 dpa. Postirradiation testing of these specimens has begun. Preliminary results from a limited number of specimens indicate a significant loss of work-hardening capability and dynamic toughness due to the irradiation. These results are consistent with data from previous low-temperature neutron irradiation experiments on these alloys.

  19. Price Impact and Survival of Irrational Traders

    OpenAIRE

    Leonid Kogan; Stephan Ross; Jiang Wang; Mark Westerfield

    2004-01-01

    Milton Friedman argued that irrational traders will consistently lose money, won’t survive and, therefore, cannot influence long run equilibrium asset prices. Since his work, survival and price impact have been assumed to be the same. In this paper, we demonstrate that survival and price impact are two independent concepts. The price impact of irrational traders does not rely on their long-run survival and they can have a significant impact on asset prices even when their wealth becomes negli...

  20. The Economic and Social Impact of Tourism

    OpenAIRE

    Gloria M. Arroyo; San Buenaventura, Mariano

    1983-01-01

    This paper analyzes the economic and social impact of tourism in Pagsanjan in which tourism development project is located. Results show that the project’s various significant impacts include increases in employment and income and stimulation of political and women’s participation. While its impact on environment and on the people’s social life has been a mixture of positive and negative results, its impact on income distribution has been trifling. To maximize the tourism multiplier, the pape...

  1. Cosmic Impacts: The DoomsDay Threat

    Science.gov (United States)

    McGaha, J.

    1998-07-01

    Recent science fiction movies (Deep Impact and Armageddon) have brought public attention to the threat of possible impacts from space. Just how real is this threat and what would be the consequences of such an impact? Can we do anything to prevent it? The survival of civilization may depend on it.

  2. Determining the Business Impact of Knowledge Management

    Science.gov (United States)

    Aaron, Bruce C.

    2009-01-01

    This case study describes an evaluation of business impact and return on investment (ROI) for the Knowledge Exchange, a knowledge management (KM) system within Accenture. The evaluation used a continuous measurement design to allow impact and ROI to be tracked across time and groups. The results demonstrated a significant positive impact on…

  3. Impact in the REF: Issues and Obstacles

    Science.gov (United States)

    Watermeyer, Richard

    2016-01-01

    This article focuses on "impact" as a new condition of research assessment for UK academics. It explores a history of resistance to an "impact agenda" and how impact as a component of the Research Excellence Framework (REF)--a system of performance based funding--is viewed by academics as an infringement to a scholarly way of…

  4. Fracture energy evaluation on 7075-T651 aluminum alloy welds determined by instrumented impact pendulum%采用改进冲击摆锤评价7075-T651合金焊缝的断裂能

    Institute of Scientific and Technical Information of China (English)

    R. R. AMBRIZ; D. JARAMILLO; C. GARCÍA; F. F. CURIEL

    2016-01-01

    采用改进冲击摆锤,研究7075-T651合金焊缝夏比试样的力−时间曲线。考虑力−时间曲线和恒冲击速率,获得不同区域的断裂能。与焊缝金属(7.88 J)和基体金属(5.37 J(纵向)和7.37 J(横向))的断裂能相比,热影响区的断裂能更高(33.6 J),这是由于焊接过程中,热力学不稳定的η′相发生组织转变。焊缝区的断裂能比基体合金的高,这是由于焊接凝固过程中产生大量孔洞。为从力−时间曲线中获得动态屈服力,对焊缝、热影响区和基体合金的屈服强度进行近似处理。断裂形貌表明,基体合金在纵向方向上呈现晶间断裂,而在横向方向上,主要为脆性(解理)断裂并伴有韧性断裂特征。而焊缝区和热影响区则呈现韧性断裂。%By using an instrumented impact pendulum, the force versus time curves of 7075-T651 aluminum welds were obtained from standard Charpy-V samples. Considering the force−time curves and constant impact velocity, the fracture energies for different zones were quantified. A fracture energy improvement for the HAZ (33.6 J) was observed in comparison with the weld metal (7.88 J), and base metal (5.37 J and 7.37 J for longitudinal and transverse directions, respectively). This toughness increment was attributed to the microstructural transformation caused by the thermodynamic instability of η′ precipitates during the welding. Fracture energy for weld metal was higher than that for base metal, probably due to pores created during solidification. Regarding the dynamic yielding force obtained from the force−time curves, an approximation to the dynamic yield strength for weld, HAZ and base metal was determined. Fracture surfaces revealed an intergranular failure for base metal in longitudinal direction, whereas a predominately brittle failure (cleavage) with some insights of ductile characteristics was observed for the transverse direction. In contrast, a ductile failure

  5. Irradiation programme HFR phase IIb - SPICE. Impact testing on up to 16.3 dpa irradiated RAFM steels. Final report for task TW2-TTMS 001b-D05

    Energy Technology Data Exchange (ETDEWEB)

    Gaganidze, E.; Dafferner, B.; Ries, H.; Rolli, R.; Schneider, H.C.; Aktaa, J.

    2008-04-15

    The objective of this work is to study the effects of neutron irradiation on the embrittlement behavior of different reduced activation ferritic/martensitic (RAFM) steels. The irradiation was carried out in the Petten High Flux Reactor (HFR) in the framework of the HFR Phase IIb (SPICE) irradiation project at a nominal dose of 16.3 dpa and at different irradiation temperatures (250-450 C). The impact properties are investigated by instrumented Charpy-V tests with subsize specimens (KLST-type). The emphasis is put on the investigation of irradiation induced embrittlement and hardening of the European RAFM reference steel for the first wall of a DEMO fusion reactor, EURO- FER97 under different heat treatment conditions. The mechanical properties of EUROFER97 are compared with the results on international reference steels (F82H-mod, OPTIFER-Ia, GA3X and MANET-I) included in the SPICE project. EUROFER97 irradiated up to 16.3 dpa between 250 and 450 C showed irradiation resistance that is comparable to those of best RAFM steels. Large low temperature (T{sub irr} {<=} 300 C) embrittlement is seen for all investigated RAFM steels. Heat treatment of EUROFER97 at higher austenitizing temperature led to the reduction of embrittlement at low temperatures (T{sub irr} {<=} 350 C). At T{sub irr} {>=} 350 C the DBTTs of the steels remain below -20 C and, hence, are well below the application temperature. Analysis of hardening vs. embrittlement behaviour indicated hardening dominated embrittlement at T{sub irr} {<=} 350 C with 0.17 {<=} C{sub 100} {<=} 0.53 C/MPa. Oxygen dispersion hardened ODS EUROFER with 0.5 wt.% Y{sub 2}O{sub 3} has been irradiated at selected irradiation temperatures. ODS EUROFER showed not satisfying impact properties already in the unirradiated condition characterized by low USE = 2.54 J and large DBTT = 135 C. Furthermore, the increase of USE for irradiation temperatures below T{sub irr} {<=} 350 C indicates not optimized fabrication process. At T{sub irr

  6. To impact or not to impact, this is not a question for BioImpacts!

    OpenAIRE

    2015-01-01

    Summary BioImpacts was launched in March 2011 as a peer-reviewed, open-access journal. Now it is the leading scientific journal of Tabriz University of Medical Sciences (TUOMS) targeting the international scientific community. With several excellent review and research papers published in recent issues, it has secured a reputable status among similar journals printed in the Middle East and worldwide. In the last year alone, one-third of its contributing authors were from universities outside ...

  7. ISI's Impact Factor as Misnomer: A Proposed New Measure To Assess Journal Impact.

    Science.gov (United States)

    Harter, Stephen P.; Nisonger, Thomas E.

    1997-01-01

    Discusses "impact factor," a measure of journal impact defined by the Institute of Scientific Information (ISI) and available in Journal Citation Reports. Argues that "impact factor" is misnamed and misused, suggesting an alternative name and interpretation of the measure, and proposes two new measures to assess the impact of…

  8. 76 FR 80346 - Notice of Availability for the Draft Environmental Impact Statement/Environmental Impact Report...

    Science.gov (United States)

    2011-12-23

    ... Department of the Army, Corps of Engineers Notice of Availability for the Draft Environmental Impact Statement/Environmental Impact Report for Proposed Berths 302-306 American President Lines (APL) Container... of Los Angeles, has completed a Draft Environmental Impact Statement/Environmental Impact Report...

  9. 78 FR 5837 - Cancellation of Environmental Impact Statement/Environmental Impact Report on the Sacramento...

    Science.gov (United States)

    2013-01-28

    ... Bureau of Reclamation Cancellation of Environmental Impact Statement/Environmental Impact Report on the... plans to continue work on a joint environmental impact statement/environmental impact report (EIS/EIR... (68 FR 44811). Dated: December 11, 2012. Anastasia T. Leigh, Regional Environmental Officer,...

  10. 75 FR 80068 - Notice of Availability of the Final Environmental Impact Report/Final Environmental Impact...

    Science.gov (United States)

    2010-12-21

    ... Bureau of Land Management Notice of Availability of the Final Environmental Impact Report/ Final Environmental Impact Statement for the Southern California Edison Eldorado-Ivanpah Transmission Project... (CPUC) have prepared a Final Environmental Impact Report (EIR)/Final Environmental Impact Statement...

  11. 77 FR 45652 - Final Program Environmental Impact Statement/Environmental Impact Report for the San Joaquin...

    Science.gov (United States)

    2012-08-01

    ... Bureau of Reclamation Final Program Environmental Impact Statement/Environmental Impact Report for the... prepared a joint Final Program Environmental Impact Statement/Environmental Impact Report (Final PEIS/R...: Notice of availability. SUMMARY: Pursuant to the National Environmental Policy Act and the...

  12. 76 FR 55703 - Draft Environmental Impact Statement/Environmental Impact Report and Notice of Public Meetings...

    Science.gov (United States)

    2011-09-08

    ... Bureau of Reclamation Draft Environmental Impact Statement/Environmental Impact Report and Notice of... public review and comment the joint draft environmental impact statement/ environmental impact report... meetings regarding the project's environmental effects. The meetings will be held on September 22,...

  13. 78 FR 68860 - Notice of Availability of a Final Environmental Impact Statement and Environmental Impact Report...

    Science.gov (United States)

    2013-11-15

    ... Bureau of Land Management Notice of Availability of a Final Environmental Impact Statement and Environmental Impact Report for the Proposed Stateline Solar Farm and Proposed California Desert Conservation... Impact Statement (EIS) and Draft Environmental Impact Report (EIR) for the Stateline Solar Farm...

  14. A Hail Size Distribution Impact Transducer

    CERN Document Server

    Lane, John E; Haskell, William D; Cox, Robert B

    2014-01-01

    An active impact transducer has been designed and tested for the purpose of monitoring hail fall in the vicinity of the Space Shuttle launch pads. An important outcome of this design is the opportunity to utilize frequency analysis to discriminate between the audio signal generated from raindrop impacts and that of hailstone impacts. The sound of hail impacting a metal plate is sub-tly but distinctly different than the sound of rain impacts. This useful characteristic permits application of signal processing algorithms that are inherently more robust than techniques relying on amplitude processing alone in the implementation of a hail disdrometer.

  15. Columbia River impact evaluation plan

    Energy Technology Data Exchange (ETDEWEB)

    1993-06-01

    As a result of past practices, four areas of the Hanford Site (the 100, 200, 300, and 1100 Areas) have been included on the US Environmental Protection Agency`s (EPA`s) National Priorities List (NPL) under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980. To accomplish the timely cleanup of the past-practice units, the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement), was signed by the Washington State Department of Ecology (Ecology), EPA, and the US Department of Energy (DOE). To support the Tri-Party Agreement, milestones were adopted. These milestones represent the actions needed to ensure acceptable progress toward Hanford Site compliance with CERCLA, RCRA, and the Washington State Hazardous Waste Management Act of 1976. This report was prepared to fulfill the requirement of Tri-Party Agreement Milestone M-30-02, which requires a plan to determine cumulative health and environmental impacts to the Columbia River. This plan supplements the CERCLA remedial investigations/feasibility studies (RI/FS) and RCRA facility investigations/corrective measures studies (RFI/CMSs) that will be undertaken in the 100 Area. To support the plan development process, existing information was reviewed and a preliminary impact evaluation based on this information was performed. The purpose of the preliminary impact evaluation was to assess the adequacy of existing data and proposed data collection activities. Based on the results of the evaluation, a plan is proposed to collect additional data or make changes to existing or proposed data collection activities.

  16. Environmental Impact of Supply Chains

    OpenAIRE

    Brînzã Georgiana

    2012-01-01

    In this research we create a method to transform the savings/ decrease in CO2 into quality increase in physical distribution. And the method consists in finding the right allocation of environmental impact (in terms of CO2 amount) from the distribution activity to every end product. We need to observe and calculate the amount of CO2 in order to know how much CO2 needs to be allocated to every product. The mechanism consists in offering to end-customers the possibility of selecting the distrib...

  17. Cultural Impacts in Managerial Accounting

    Directory of Open Access Journals (Sweden)

    Flavius Guinea

    2006-08-01

    Full Text Available From the theoretical point of view, it has been stated that there is a considerable probability that some cultural aspects could affect the economic environment and, consequently, the managerial accounting. While this statement has a certain suppositional degree, we will try to test the importance of culture within the managerial accounting. Several empirical approaches underline the existence of a powerful impact of the national culture on the managerial accounting systems. Moreover, it is clear for everybody that the companies’ strategic objectives are often expressed in numerical terms, but they are chosen according to the culture.

  18. Soft Matter under Exogenic Impacts

    CERN Document Server

    Rzoska, Sylwester J

    2007-01-01

    ‘Soft Matter Under Exogenic Impacts’ is fairly unique in supplying a comprehensive presentation of high pressures, negative pressures, random constraints and strong electric field exogenic (external) impacts on various soft matter systems. These are: (i) critical liquids, (ii) glass formers, such as supercooled liquids including water, polymers and resins, (iii) liquid crystals and (iv) bio-liquids. It is, because of this, an excellent guide in this novel and still puzzling research area. Besides new results, the identification of new types of physical behavior, new technological materials, ultimate verification of condensed and soft matter physics models, new applications in geophysics, biophysics, biotechnology, are all discussed in this book.

  19. The social impact of computers

    CERN Document Server

    Rosenberg, Richard S

    1992-01-01

    The Social Impact of Computers should be read as a guide to the social implications of current and future applications of computers. Among the basic themes presented are the following: the changing nature of work in response to technological innovation as well as the threat to jobs; personal freedom in the machine age as manifested by challenges to privacy, dignity, and work; the relationship between advances in computer and communications technology and the possibility of increased centralization of authority; and the emergence and influence of artificial intelligence and its role in decision

  20. Nanomedicine science, business, and impact

    CERN Document Server

    Hehenberger, Michael

    2015-01-01

    By covering the science, business, and societal impact of nanomedicine, this book makes a strong case for funding of basic research, for effective translation of scientific breakthroughs into clinical care of patients, and for close collaboration among all stakeholders in the healthcare ecosystem. It covers the underlying science and technology of nanomedicine in detail to help understand the great promise of nanomedicine across all disease areas. Although rich and deep in content, the book attempts to introduce the topic of nanomedicine to a wide audience. Scientific jargon is avoided and adv

  1. Wind energy impact of turbulence

    CERN Document Server

    Hölling, Michae; Ivanell, Stefan

    2014-01-01

    This book presents the results of the seminar ""Wind Energy and the Impact of Turbulence on the Conversion Process"" which was supported from three societies, namely the EUROMech, EAWE and ERCOFATC and took place in Oldenburg, Germany in spring 2012.The seminar was one of the first scientific meetings devoted to the common topic of wind energy and basic turbulence. The established community of researchers working on the challenging puzzle of turbulence for decades met the quite young community of researchers, who face the upcoming challenges in the fast growing field of wind energy application

  2. Impact of floats on water

    CERN Document Server

    de Divitiis, Nicola; 10.1017/S002211200200229X

    2009-01-01

    The impact of a wedge-shaped body on the free surface of a weightless inviscid incompressible liquid is considered. Both symmetrical and unsymmetrical entries at constant velocity are dealt with. The differential problem corresponds to the physico-mathematical model of a distribution of potential singularities and, in particular, the flow singularities at the ends of the wetted regions are represented by sinks. A conformal transformation of the flow field is adopted and the unknown intensities of the discontinuities are found by an optimization procedure, together with the solution of the nonlinear free-surface problem. The flow separation at a sideslip is also considered.

  3. Physics of soft impact and cratering

    CERN Document Server

    Katsuragi, Hiroaki

    2016-01-01

    This book focuses on the impact dynamics and cratering of soft matter to describe its importance, difficulty, and wide applicability to planetary-related problems. A comprehensive introduction to the dimensional analysis and constitutive laws that are necessary to discuss impact mechanics and cratering is first provided. Then, particular coverage is given to the impact of granular matter, which is one of the most crucial constituents for geophysics. While granular matter shows both solid-like and fluid-like behaviors, neither solid nor fluid dynamics is sufficient to fully understand the physics of granular matter. In order to reveal its fundamental properties, extensive impact tests have been carried out recently. The author reveals the findings of these recent studies as well as what remains unsolved in terms of impact dynamics. Impact crater morphology with various soft matter impacts also is discussed intensively. Various experimental and observational results up to the recent Itokawa asteroid’s terrain...

  4. Influences of carbon nanofillers on mechanical performance of epoxy resin polymer

    Science.gov (United States)

    Singh, Shraddha; Srivastava, V. K.; Prakash, Rajiv

    2015-03-01

    The influence of multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GnPs) on epoxy resin was investigated to compare their mechanical properties. MWCNT/epoxy resin and GnP/epoxy resin composites were compared with each other for their tensile strength, compressive strength, Charpy Impact and Izod impact energy with the variation of weight percentage ratio of nanofiller ranging from 0.5, 1.0, 2.0 and 3.0, respectively. The result shows that GnP/epoxy resin composite gave better tensile and compressive strength compared to MWCNT/epoxy resin composite whereas Izod impact energy, Charpy impact energy and dynamic fracture toughness of MWCNT/epoxy resin composite resulted in better impact resistance than the GnP/epoxy resin composite. Thermal stability and microstructural properties of composites were measured using Thermogravimetric analysis (TGA), transmission electron microscope (TEM) and scanning electron microscope (SEM).

  5. Organized crime impact study highlights

    Energy Technology Data Exchange (ETDEWEB)

    Porteous, S.D.

    1998-10-01

    A study was conducted to address the issue of how organized crime impacts on Canadians and their communities both socially and economically. As far as environmental crime is concerned, three main areas of concern have been identified: (1) illicit trade in ozone depleting substances, (2) illicit hazardous waste treatment, and (3) disposal of illicit trade in endangered species. To gauge the magnitude of organized crime activity, the market value of worldwide illegal trafficking in illicit drugs was estimated to be as high as $100 billion worldwide (between $1.4 to 4 billion in Canada). It is suspected that Canada supplies a substantial portion of the U.S. black market in chlorofluorocarbons with most of the rest being supplied from Mexico. Another area of concern involves the disposal of hazardous wastes. Canada produces approximately 5.9 million tonnes of hazardous waste annually. Of these, 3.2 million tonnes are sent to off-site disposal facilities for specialized treatment and recycling. The treatment of hazardous waste is a very profitable business, hence vulnerable to fraudulent practices engaged in by organized crime groups. Environmental implications of this and other environmental crimes, as well as their economic, commercial, health and safety impact were examined. Other areas of organized crime activity in Canada (drugs, economic crimes, migrant trafficking, counterfeit products, motor vehicle theft, money laundering) were also part of the study.

  6. Radioecological impacts of tin mining.

    Science.gov (United States)

    Aliyu, Abubakar Sadiq; Mousseau, Timothy Alexander; Ramli, Ahmad Termizi; Bununu, Yakubu Aliyu

    2015-12-01

    The tin mining activities in the suburbs of Jos, Plateau State, Nigeria, have resulted in technical enhancement of the natural background radiation as well as higher activity concentrations of primordial radionuclides in the topsoil of mining sites and their environs. Several studies have considered the radiological human health risks of the mining activity; however, to our knowledge no documented study has investigated the radiological impacts on biota. Hence, an attempt is made to assess potential hazards using published data from the literature and the ERICA Tool. This paper considers the effects of mining and milling on terrestrial organisms like shrubs, large mammals, small burrowing mammals, birds (duck), arthropods (earth worm), grasses, and herbs. The dose rates and risk quotients to these organisms are computed using conservative values for activity concentrations of natural radionuclides reported in Bitsichi and Bukuru mining areas. The results suggest that grasses, herbs, lichens, bryophytes and shrubs receive total dose rates that are of potential concern. The effects of dose rates to specific indicator species of interest are highlighted and discussed. We conclude that further investigation and proper regulations should be set in place in order to reduce the risk posed by the tin mining activity on biota. This paper also presents a brief overview of the impact of mineral mining on biota based on documented literature for other countries.

  7. Radiation modified high impact polystyrene

    Science.gov (United States)

    Jelčić, Želimir; Ranogajec, Franjo

    2012-09-01

    The purpose of applying high energy (ionising) radiation with absorbed doses up to 1 MGy was to achieve controllable changes in mechanical properties of high impact polystyrene (PS-HI) and, at the same time, to investigate the possibility of using reprocessed irradiated polymeric material. Dielectric relaxation of a radiation modified high impact polystyrene (PS-HI) has been investigated by the time dependence of charging and discharging current. The transient currents for the irradiated PS-HI were well approximated by the power function of the logarithm of time and related to the fractal dimension. It was also shown that yield strength and tensile strength increase while elongation at break decreases with increasing absorbed dose. The specimen prepared by a post-irradiation moulding gave higher melt flow rate than those of specimen formed before irradiation. These results indicate that after radiation the system of PS-HI is reprocessable. It is concluded that an oxygen environment at the beginning of irradiation leads to enhanced chain scission at the expense of crosslinks via peroxide formation and causes oxidative degradation of the main polymer chain of irradiated PS-HI at a low absorbed dose. However, at higher absorbed doses the quasi-inert environment has been established and crosslinking, due to recombination of macroradicals, is dominant.

  8. MIGRATION IMPACT ON ECONOMICAL SITUATION

    Directory of Open Access Journals (Sweden)

    Virginia COJOCARU

    2016-01-01

    Full Text Available This paper presents recent trends and flows of labor migration and its impact on economic and social life. Main aim of this research sets up the influence of the migration on the European economics and its competitiveness. Methods of research are: method of comparison, analysis method, method of deduction, method of statistics, modeling method. The economic impact of migration has been intensively studied but is still often driven by ill-informed perceptions, which, in turn, can lead to public antagonism towards migration. These negative views risk jeopardising efforts to adapt migration policies to the new economic and demographic challenges facing many countries. Migration Policy looks at the evidence for how immigrants affect the economy in three main areas: The labour market, public purse and economic growth. In Europe, the scope of labour mobility greatly increased within the EU/EFTA zones following the EU enlargements of 2004, 2007 and 2014-2015. This added to labour markets’ adjustment capacity. Recent estimates suggest that as much as a quarter of the asymmetric labour market shock – that is occurring at different times and with different intensities across countries – may have been absorbed by migration within a year.

  9. Effect of microstructure on the impact toughness of high strength steels

    Directory of Open Access Journals (Sweden)

    Gutiérrez, Isabel

    2014-12-01

    Full Text Available One of the major challenges in the development of new steel grades is to get increasingly high strength combined with a low ductile brittle transition temperature and a high upper shelf energy. This requires the appropriate microstructural design. Toughness in steels is controlled by different microstructural constituents. Some of them, like inclusions, are intrinsic while others happening at different microstructural scales relate to processing conditions. A series of empirical equations express the transition temperature as a sum of contributions from substitutional solutes, free nitrogen, carbides, pearlite, grain size and eventually precipitation strengthening. Aimed at developing a methodology that could be applied to high strength steels, microstructures with a selected degree of complexity were produced at laboratory in a Nb-microalloyed steel. As a result a model has been developed that consistently predicts the Charpy curves for ferrite-pearlite, bainitic and quenched and tempered microstructures using as input data microstructural parameters. This model becomes a good tool for microstructural design.El desarrollo de nuevos grados de acero se tropieza con frecuencia con la necesidad de incrementar la resistencia mecánica al mismo tiempo que se reduce la temperatura de transición dúctil-frágil y se eleva la energía del palier dúctil. Hacer frente a este reto requiere un diseño microestructural. La tenacidad en aceros está controlada por diferentes constituyentes microestructurales. Algunos de ellos, como las inclusiones son intrínsecos, pero otros que se manifiestan a diferentes escalas microestructurales dependen de las condiciones de proceso. Existen algunas ecuaciones empíricas que permiten calcular para ferrita-perlita en aceros de bajo carbono la temperatura de transición como suma de contribuciones de elementos en solución sólida, nitrógeno libre, carburos, fracción de perlita, tamaño de grano y, eventualmente

  10. Ice Particle Impacts on a Moving Wedge

    Science.gov (United States)

    Vargas, Mario; Struk, Peter M.; Kreeger, Richard E.; Palacios, Jose; Iyer, Kaushik A.; Gold, Robert E.

    2014-01-01

    This work presents the results of an experimental study of ice particle impacts on a moving wedge. The experiment was conducted in the Adverse Environment Rotor Test Stand (AERTS) facility located at Penn State University. The wedge was placed at the tip of a rotating blade. Ice particles shot from a pressure gun intercepted the moving wedge and impacted it at a location along its circular path. The upward velocity of the ice particles varied from 7 to 12 meters per second. Wedge velocities were varied from 0 to 120 meters per second. Wedge angles tested were 0 deg, 30 deg, 45 deg, and 60 deg. High speed imaging combined with backlighting captured the impact allowing observation of the effect of velocity and wedge angle on the impact and the post-impact fragment behavior. It was found that the pressure gun and the rotating wedge could be synchronized to consistently obtain ice particle impacts on the target wedge. It was observed that the number of fragments increase with the normal component of the impact velocity. Particle fragments ejected immediately after impact showed velocities higher than the impact velocity. The results followed the major qualitative features observed by other researchers for hailstone impacts, even though the reduced scale size of the particles used in the present experiment as compared to hailstones was 4:1.

  11. International Database of Volcanic Ash Impacts

    Science.gov (United States)

    Wallace, K.; Cameron, C.; Wilson, T. M.; Jenkins, S.; Brown, S.; Leonard, G.; Deligne, N.; Stewart, C.

    2015-12-01

    Volcanic ash creates extensive impacts to people and property, yet we lack a global ash impacts catalog to organize, distribute, and archive this important information. Critical impact information is often stored in ephemeral news articles or other isolated resources, which cannot be queried or located easily. A global ash impacts database would improve 1) warning messages, 2) public and lifeline emergency preparation, and 3) eruption response and recovery. Ashfall can have varying consequences, such as disabling critical lifeline infrastructure (e.g. electrical generation and transmission, water supplies, telecommunications, aircraft and airports) or merely creating limited and expensive inconvenience to local communities. Impacts to the aviation sector can be a far-reaching global issue. The international volcanic ash impacts community formed a committee to develop a database to catalog the impacts of volcanic ash. We identify three user populations for this database: 1) research teams, who would use the database to assist in systematic collection, recording, and storage of ash impact data, and to prioritize impact assessment trips and lab experiments 2) volcanic risk assessment scientists who rely on impact data for assessments (especially vulnerability/fragility assessments); a complete dataset would have utility for global, regional, national and local scale risk assessments, and 3) citizen science volcanic hazard reporting. Publication of an international ash impacts database will encourage standardization and development of best practices for collecting and reporting impact information. Data entered will be highly categorized, searchable, and open source. Systematic cataloging of impact data will allow users to query the data and extract valuable information to aid in the development of improved emergency preparedness, response and recovery measures.

  12. Determination of the EOS maragingsteel MS1 material resistance at low temperatures

    Directory of Open Access Journals (Sweden)

    J. Dobránsky

    2016-07-01

    Full Text Available This article deals with determination of the EOS MaragingSteel MS1 material resistance at different low temperatures. Material resistance was evaluated in two types of standardized specimens. The impact energy at the specimens tested at 10 °C, values for the specimens with no notch were compared to the V - notch specimens, higher by approximately one - third. When the temperature dropped to 0 °C, the values of the impact energy slightly decreased as well. It therefore follows that lower temperatures result in decrease in the values of the impact strength. This experiment provided us with the opportunity to find out whether the decrease in temperature impacts the resistance of the tested material.

  13. International impact research and management

    Science.gov (United States)

    Marion, J.L.; Leung, Y.; Hammitt, William E.; Cole, David N.

    1998-01-01

    To be sustainable, ecotourism requires the protection of natural environments and processes both from development and operation of the tourism infrastructure, and from the activities of ecotourists within protected areas. This book chapter reviews the international literature on the study of visitor or recreation-related resource impacts with special reference to ecotourism. Four case examples are presented to characterize the geographic scope, focus, and principal findings of this recreation ecology literature and its relevance to ecotourism management. Case examples include the Cairngorms National Nature Reserve, Scotland; the Great Barrier Reef, Australia; the Central American tropics; and wildlife viewing in Kenya?s protected areas. Implications for the management of international protected areas and ecotourism resources are discussed.

  14. Synthetic biology character and impact

    CERN Document Server

    Pade, Christian; Wigger, Henning; Gleich, Arnim

    2015-01-01

    Synthetic Biology is already an object of intensive debate. However, to a great extent the discussion to date has been concerned with fundamental ethical, religious and philosophical questions. By contrast, based on an investigation of the field’s scientific and technological character, this book focuses on new functionalities provided by synthetic biology and explores the associated opportunities and risks. Following an introduction to the subject and a discussion of the most central paradigms and methodologies, the book provides an overview of the structure of this field of science and technology. It informs the reader about the current stage of development, as well as topical problems and potential opportunities in important fields of application. But not only the science itself is in focus. In order to investigate its broader impact, ecological as well as ethical implications will be considered, paving the way for a discussion of responsibilities in the context of a field at a transitional crossroads be...

  15. Hydrocarbon Rocket Technology Impact Forecasting

    Science.gov (United States)

    Stuber, Eric; Prasadh, Nishant; Edwards, Stephen; Mavris, Dimitri N.

    2012-01-01

    Ever since the Apollo program ended, the development of launch propulsion systems in the US has fallen drastically, with only two new booster engine developments, the SSME and the RS-68, occurring in the past few decades.1 In recent years, however, there has been an increased interest in pursuing more effective launch propulsion technologies in the U.S., exemplified by the NASA Office of the Chief Technologist s inclusion of Launch Propulsion Systems as the first technological area in the Space Technology Roadmaps2. One area of particular interest to both government agencies and commercial entities has been the development of hydrocarbon engines; NASA and the Air Force Research Lab3 have expressed interest in the use of hydrocarbon fuels for their respective SLS Booster and Reusable Booster System concepts, and two major commercially-developed launch vehicles SpaceX s Falcon 9 and Orbital Sciences Antares feature engines that use RP-1 kerosene fuel. Compared to engines powered by liquid hydrogen, hydrocarbon-fueled engines have a greater propellant density (usually resulting in a lighter overall engine), produce greater propulsive force, possess easier fuel handling and loading, and for reusable vehicle concepts can provide a shorter turnaround time between launches. These benefits suggest that a hydrocarbon-fueled launch vehicle would allow for a cheap and frequent means of access to space.1 However, the time and money required for the development of a new engine still presents a major challenge. Long and costly design, development, testing and evaluation (DDT&E) programs underscore the importance of identifying critical technologies and prioritizing investment efforts. Trade studies must be performed on engine concepts examining the affordability, operability, and reliability of each concept, and quantifying the impacts of proposed technologies. These studies can be performed through use of the Technology Impact Forecasting (TIF) method. The Technology Impact

  16. Metabolic impact of shift work.

    Science.gov (United States)

    Zimberg, Ioná Zalcman; Fernandes Junior, Silvio A; Crispim, Cibele Aparecida; Tufik, Sergio; de Mello, Marco Tulio

    2012-01-01

    In developing countries, shift work represents a considerable contingent workforce. Recently, studies have shown that overweight and obesity are more prevalent in shift workers than day workers. In addition, shift work has been associated with a higher propensity for the development of many metabolic disorders, such as insulin resistance, diabetes, dislipidemias and metabolic syndrome. Recent data have pointed that decrease of the sleep time, desynchronization of circadian rhythm and alteration of environmental aspects are the main factors related to such problems. Shortened or disturbed sleep is among the most common health-related effects of shift work. The plausible physiological and biological mechanisms are related to the activation of the autonomic nervous system, inflammation, changes in lipid and glucose metabolism, and related changes in the risk for atherosclerosis, metabolic syndrome, and type II diabetes. The present review will discuss the impact of shift work on obesity and metabolic disorders and how disruption of sleep and circadian misalignment may contribute to these metabolic dysfunctions.

  17. Environmental impact of Supernova Remnants

    CERN Document Server

    Dubner, Gloria

    2015-01-01

    The explosion of a supernovae (SN) represents the sudden injection of about 10^51 ergs of thermal and mechanical energy in a small region of space, causing the formation of powerful shock waves that propagate through the interstellar medium at speeds of several thousands of km/s. These waves sweep, compress and heat the interstellar material that they encounter, forming the supernova remnants. Their evolution over thousands of years change forever, irreversibly, not only the physical but also the chemical properties of a vast region of space that can span hundreds of parsecs. This contribution briefly analyzes the impact of these explosions, discussing the relevance of some phenomena usually associated with SNe and their remnants in the light of recent theoretical and observational results.

  18. CID Post-impact fireball

    Science.gov (United States)

    1984-01-01

    The B-720 after impact and sliding through the wing openers is becoming enveloped in a fireball. The right wing appears to be folding over as the aircraft continues to slide. In a typical aircraft crash, fuel spilled from ruptured fuel tanks forms a fine mist that can be ignited by a number of sources at the crash site. In 1984 the NASA Dryden Flight Research Facility (after 1994 a full-fledged Center again) and the Federal Aviation Administration (FAA) teamed-up in a unique flight experiment called the Controlled Impact Demonstration (CID), to test crash a Boeing 720 aircraft using standard fuel with an additive designed to supress fire. The additive, FM-9, a high-molecular-weight long-chain polymer, when blended with Jet-A fuel had demonstrated the capability to inhibit ignition and flame propagation of the released fuel in simulated crash tests. This anti-misting kerosene (AMK) cannot be introduced directly into a gas turbine engine due to several possible problems such as clogging of filters. The AMK must be restored to almost Jet-A before being introduced into the engine for burning. This restoration is called 'degradation' and was accomplished on the B-720 using a device called a 'degrader.' Each of the four Pratt & Whitney JT3C-7 engines had a 'degrader' built and installed by General Electric (GE) to break down and return the AMK to near Jet-A quality. In addition to the AMK research the NASA Langley Research Center was involved in a structural loads measurement experiment, which included having instrumented dummies filling the seats in the passenger compartment. Before the final flight on December 1, 1984, more than four years of effort passed trying to set-up final impact conditions considered survivable by the FAA. During those years while 14 flights with crews were flown the following major efforts were underway: NASA Dryden developed the remote piloting techniques necessary for the B-720 to fly as a drone aircraft; General Electric installed and tested

  19. The Proposed Nalbach (Saarland, Germany) Impact Site: Is it a Companion to the Chiemgau (Southeast Bavaria, Germany) Impact Strewn Field?

    Science.gov (United States)

    Ernstson, K.; Müller, W.; Neumair, A.

    2013-09-01

    Peculiar finds have been attributed to a possible Holocene meteorite impact. They show absolutely identical parallels to impact features from the Chiemgau impact. If the sites can be dated synchronous a 500 km sized impact event might be targeted.

  20. Economic Impacts of Power Shortage

    Directory of Open Access Journals (Sweden)

    Peng Ou

    2016-07-01

    Full Text Available The electricity industry is a basic industry of the national economy. It has experienced several large-scale power shortages, hard power shortage and soft power shortage, which have brought a great threat to China’s sustainable economic development. To solve this problem better, it is necessary to make a quantitative assessment of the economic impacts of power shortage. The CGE model is commonly used for simulating economic shocks and policy effects. It describes supply, demand and equilibrium in different markets by simulating the economic mechanism through a set of equations. Once changed, the exogenous variables will affect a certain part of the system and then the whole system, leading to changes in quantities and prices. The equilibrium state will also change from one to another. A static CGE model is built in this paper, and the Social Accounting Matrix (SAM of eight sectors of China in 2007 is compiled, in order to simulate the economic impacts of hard power shortage and soft power shortage. Simulation results show that the negative effects of power shortage on economic development are very significant, and the effects vary in different sectors. Especially, under the background of hard power shortage, the industrial sector suffers most. The economic cost of power shortage is considerable, and the main reason for it is the specific administrative pricing system in China. The low electricity price in the long term will lead to insufficient construction and hard power shortage; moreover, that in the short run would result in soft power shortage. In order to solve the problem of power shortage completely, power system reform is inevitable.

  1. Programme impact on current contraception in Bangladesh.

    Science.gov (United States)

    Latif, M A

    1994-03-01

    "This paper analyses the impact of three credit programmes--the Bangladesh Rural Advancement Committee (BRAC), the Bangladesh Rural Development Board's Rural Development-12 (BRDB RD-12), and the Grameen Bank (GB), on current rate of contraception. These programmes are targeted to alleviate poverty by providing group-based credit to the rural poor in creating self employment opportunities. With small credits, these programmes combine family planning activities in terms of consciousness raising, awareness building and motivation. Sample survey data are used to analyse the problem of impact evaluation. The analyses show that the BRAC and the GB programmes have [a] significantly positive impact on the current rate of contraception, while the BRDB RD-12 programme does not have any such impact. It is also found that education, both of female[s] and male[s] separately, and child survivorship have independently positive impact[s] on current contraception."

  2. Perfect fluid flow from granular jet impact

    CERN Document Server

    Ellowitz, Jake; Zhang, Wendy W

    2012-01-01

    Experiments on the impact of a densely-packed jet of non-cohesive grains onto a fixed target show that the impact produces an ejecta sheet comprised of particles in collimated motion. The ejecta sheet leaves the target at a well-defined angle whose value agrees quantitatively with the sheet angle produced by water jet impact. Motivated by these experiments, we examine the idealized problem of dense granular jet impact onto a frictionless target in two dimensions. Numerical results for the velocity and pressure fields within the granular jet agree quantitatively with predictions from an exact solution for 2D perfect-fluid impact. This correspondence demonstrates that the continuum limit controlling the coherent collective motion in dense granular impact is Euler flow.

  3. The Impact of Tourism upon Natural Capital

    OpenAIRE

    Gabriela Cornelia Piciu; Carmen Trica

    2011-01-01

    Tourism now represents a major management problem to be faced by those who are responsible for theprotection and control the host areas and their facilities. We have identified impacts from tourist-relatedtransportation, tourist-related development, tourist activities including some recreational activities such as boating,and direct impacts of the lodging and cruise industries. Although this discussion focuses on environmental impacts.After we analyze the influence that providers of tourism s...

  4. Environmental Impact of Teleworking and Teleshopping

    DEFF Research Database (Denmark)

    Falch, Morten

    This paper analyses the impact of two ICT applications on the total demand for transport (telework and teleshopping). These applications are selected as they were expected to be among the applications with the highest potential for savings in transport. The analysis indicates that the total impact...... is limited and might be even negative if rebound effects are included, and that the promotion of ICT applications must be accommodated by other measures before a noticeable positive impact on transport behaviour can be achieved....

  5. Simulating structural response to water impact

    OpenAIRE

    Campbell, James C; Vignjevic, Rade

    2012-01-01

    Structural response to water impact is important for several areas, including the aerospace and marine industries. Aircraft must be designed to cope with ditching and offshore structures are subject to extreme wave impact and green water loading. The goal is a reliable technique for predicting the structural response to extreme water loading. This is a complex problem involving the interaction of non-linear fluid behaviour (breaking waves, fluid impact) with non-linear structural behaviour (l...

  6. Third International Conference on Large Meteorite Impacts

    Science.gov (United States)

    2003-01-01

    The Third International Conference on Large Meteorite Impacts (formerly Large Meteorite Impacts and Planetary Evolution) was held August 5-7, 2003, at the Kloesterle, Noerdlingen. The conference addressed a wide range of topics relating to planetary impacts and their effects on planetary crusts, climate, life on Earth, rocks, and rock-forming minerals. This CD-ROM contains the preface, table of contents, program, abstracts and indexes.

  7. Impact behaviour of stiffened steel plates

    OpenAIRE

    Sølvernes, Sindre Hellem

    2015-01-01

    The impact behavior of stiffened steel plates subjected to impact loading from concentrated loads was studied experimentally and numerically. Both dynamic and quasi-static tests of stiffened steel plates with geometry adopted from a typical external deck area on an offshore platform were conducted. The quasi-static tests were performed to study the relationship between dynamic impact behavior and the corresponding static ones. All tests were carried out in scale 1:4. To allow the executio...

  8. VISION AND ITS IMPACT ON TEAM SUCCESS

    OpenAIRE

    Lynn, Gary S.; Faruk KALAY

    2015-01-01

    A strong vision is a main predictor for both organizational and team success. Although many studies conclude that vision is important at the organizational level, the impacts of vision on innovation/teams have received far less attention. The purpose of this paper is to discuss vision components and explore its impacts on team performance. After studying the vision on a series of 12 innovations at three companies (Apple, IBM, and HP), we empirically tested the impact of the three components o...

  9. Business model elements impacting cloud computing adoption

    DEFF Research Database (Denmark)

    Bogataj, Kristina; Pucihar, Andreja; Sudzina, Frantisek

    The paper presents a proposed research framework for identification of business model elements impacting Cloud Computing Adoption. We provide a definition of main Cloud Computing characteristics, discuss previous findings on factors impacting Cloud Computing Adoption, and investigate technology a...... blocks are investigated: Product Innovation, Infrastructure management, Customer relationship, Financial Aspects.......The paper presents a proposed research framework for identification of business model elements impacting Cloud Computing Adoption. We provide a definition of main Cloud Computing characteristics, discuss previous findings on factors impacting Cloud Computing Adoption, and investigate technology...

  10. Impact wear behaviors of Hadfield manganese steel

    Institute of Scientific and Technical Information of China (English)

    FANG Liang; XU Yun-hua; CEN Qi-hong; ZHU Jin-hua

    2005-01-01

    Impact wear behaviors of Hadfield manganese steel at different impact angles were investigated. The results of impact wear tests show that there exists a critical impact load for Hadfield steel. The wear rate suddenly turns down after some impact cycles when the impact load is greater than the critical load. The critical impact load is smaller than 8.2 J in this research because the nano-sized austenitic grains embedded in amorphous delay the crack propagation in subsurface. From high resolution transmission electron microscope (HRTEM) examination of subsurface microstructure, it is found that a large amount of nano-sized grains embedded in bulk amorphous matrix are fully developed and no martensitic transformation occurs during the impact wear process. The analytical results of worn surface morphology and debris indicate that the initiation of crack, propagation and spalling are restricted in the amorphous phase, resulting in the size distribution of debris in nano-sizes, which is the reason why the wear rate of Hadfield steel is greatly decreased at high impact load.

  11. Impact force of a falling drop

    Science.gov (United States)

    Soto, Dan; Clanet, Cristophe; Quere, David; Xavier Boutillon Collaboration

    2012-11-01

    Controlling droplet deposition is crucial in many industrial processes such as spraying pesticides on crops, inkjet printing or spray coating. Therefore, the dynamics of drop impacts have been extensively studied for more than one century. However, few literature describe the impacting force of a drop on a solid flat surface, although it might be a way to measure the size distribution of a collection of falling drops. We investigated experimentally how the instantaneous force at impact depends on impact velocity and drop radius. We also propose a new model to understand our observations. Physique et Mecanique des Milieux Heterogenes, CNRS, ESPCI, Paris France & Ladhyx, CNRS, Ecole Polytechnique, Palaiseau, France.

  12. Rubber Impact on 3D Textile Composites

    Science.gov (United States)

    Heimbs, Sebastian; Van Den Broucke, Björn; Duplessis Kergomard, Yann; Dau, Frederic; Malherbe, Benoit

    2012-06-01

    A low velocity impact study of aircraft tire rubber on 3D textile-reinforced composite plates was performed experimentally and numerically. In contrast to regular unidirectional composite laminates, no delaminations occur in such a 3D textile composite. Yarn decohesions, matrix cracks and yarn ruptures have been identified as the major damage mechanisms under impact load. An increase in the number of 3D warp yarns is proposed to improve the impact damage resistance. The characteristic of a rubber impact is the high amount of elastic energy stored in the impactor during impact, which was more than 90% of the initial kinetic energy. This large geometrical deformation of the rubber during impact leads to a less localised loading of the target structure and poses great challenges for the numerical modelling. A hyperelastic Mooney-Rivlin constitutive law was used in Abaqus/Explicit based on a step-by-step validation with static rubber compression tests and low velocity impact tests on aluminium plates. Simulation models of the textile weave were developed on the meso- and macro-scale. The final correlation between impact simulation results on 3D textile-reinforced composite plates and impact test data was promising, highlighting the potential of such numerical simulation tools.

  13. College Impact Theories Past and Present

    Science.gov (United States)

    Ozaki, C. Casey

    2016-01-01

    This chapter critically examines the fit and applicability of foundational college impact theories to the community college context and students. Implications for the literature and campuses are explored.

  14. Impact Accelerations of Barefoot and Shod Running.

    Science.gov (United States)

    Thompson, M; Seegmiller, J; McGowan, C P

    2016-05-01

    During the ground contact phase of running, the body's mass is rapidly decelerated resulting in forces that propagate through the musculoskeletal system. The repetitive attenuation of these impact forces is thought to contribute to overuse injuries. Modern running shoes are designed to reduce impact forces, with the goal to minimize running related overuse injuries. Additionally, the fore/mid foot strike pattern that is adopted by most individuals when running barefoot may reduce impact force transmission. The aim of the present study was to compare the effects of the barefoot running form (fore/mid foot strike & decreased stride length) and running shoes on running kinetics and impact accelerations. 10 healthy, physically active, heel strike runners ran in 3 conditions: shod, barefoot and barefoot while heel striking, during which 3-dimensional motion analysis, ground reaction force and accelerometer data were collected. Shod running was associated with increased ground reaction force and impact peak magnitudes, but decreased impact accelerations, suggesting that the midsole of running shoes helps to attenuate impact forces. Barefoot running exhibited a similar decrease in impact accelerations, as well as decreased impact peak magnitude, which appears to be due to a decrease in stride length and/or a more plantarflexed position at ground contact.

  15. Mechanical processes with repeated attenuated impacts

    CERN Document Server

    Nagaev, R F

    1999-01-01

    This book is devoted to considering in the general case - using typical concrete examples - the motion of machines and mechanisms of impact and vibro-impact action accompanied by a peculiar phenomenon called "impact collapse". This phenomenon is that after the initial collision, a sequence of repeated gradually quickening collisions of decreasing-to-zero intensity occurs, with the final establishment of protracted contact between the interacting bodies. The initiation conditions of the impact collapse are determined and calculation techniques for the quantitative characteristics of the corresp

  16. Crater and cavity depth in hypervelocity impact

    Science.gov (United States)

    Kadono, T.; Fujiwara, A.

    2003-04-01

    Hypervelocity impact experiments with low-density mediums (e.g., foams) have been so far carried out to develop the instruments for intact capture of interplanetary dust particles. The results show that the impact leads a "cavity", a cylindrical or carrot (spindle) shaped vestige. Its shape depends on the condition of projectiles; when impact velocity is so low that projectiles are intact, the depth increases with impact velocity, while it decreases or is constant with impact velocity when the impact velocity is so high that projectiles are broken (e.g., Kadono, Planet. Space Sci. 47, 305--318, 1999). On the other hand, as described by Summers (NASA TN D-94, 1959), crater shape with high density targets (comparable to projectile density) also changes with impact velocity. At low velocities, the strength of projectile's materials is greater than the dynamic impact pressure and the projectile penetrates the target intact. The crater produced is deep and narrow. With increase in impact velocity, a point is reached at which the impact pressure is sufficient to cause the projectile to fragment into a few large pieces at impact. Then as the impact velocity is increased further, the projectile shatters into numerous small pieces and the penetration actually decreases. Finally a velocity is reached at which the typical fluid impact occurs, the crater formed is nearly hemispherical in shape. It appears that the situation in cavity formation with low density targets is quite similar to that in cratering with high density targets at low impact velocity. This similarity allows us to discuss cavity formation and cratering in a unified view. As described above, the previous experiments clearly suggest that the condition of projectiles plays important roles in both cratering and cavity formation. Hence here, by introducing a parameter that characterizes the condition of projectiles at the instance of impact, cratering processes such as projectile penetration and shock wave

  17. CANINE IMPACTIONS: AN ORTHODONTIST’S PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    Harikrishna

    2014-11-01

    Full Text Available : Impacted teeth are those which are not predictable and do not erupt absolutely based on clinical and radiographic assessment. Certain impactions can be complicated and the outcome unpredictable if the tooth is positioned unfavourably either horizontally or vertically in the alveolar bone. Presence of canines buccally, palatally or lingually can be seen using various diagnostic methods. Factors that interfere with its development and eruption have influence on aesthetics’, function and stability. A detailed understanding of the management of impacted teeth is essential for a stable and aesthetic result. So, we put forth the most common procedures which can be carried out by general dentists in managing impacted maxillary canines.

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

    Science.gov (United States)

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

    2015-12-01

    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.

  19. INFLUENCE OF IMPACT MODIFIER AND COUPLING AGENT ON IMPACT STRENGTH OF WOOD FLOUR / RECYCLED PLASTIC COMPOSITES

    Directory of Open Access Journals (Sweden)

    Saman GHAHRI

    2014-03-01

    Full Text Available In this research, the improvement of impact strength of wood flour/recycled polypropylene (PP composites was investigated. The PP (virgin and recycled polypropylene and wood flour (WF were compounded at 50% by weight wood flour loading in a counter-rotating twin-screw extruder in the presence MAPP and two types of impact modifiers (ethylene vinyl acetate (EVA and ethylene/propylene/diene terpolymer (EPDM, to produce wood flour-PP composites specimen. The results showed that the composites containing recycled PP exhibited significantly lower impact strength values than those of containing virgin PP. The addition of MAPP, EVA and EPDM in the specimens increased their impact strength. In the presence of MAPP, higher increase in impact strength of the recycled PP/WF composites was observed due to impact modifiers. Both impact modifiers increased the impact strength of the PP/WF composites but the addition of EVA gave the greatest improvements in impact strength. Although the addition of impact modifiers and MAPP increased the impact strength of composites containing recycled PP, such values were still significantly lower than those of containing virgin PP (not modified with MAPP or impact modifier. The use of impact modifiers decreased the flexural properties of the recycled PP/WF composites

  20. A closer look at the fracture toughness of ferritic/martensitic steels

    Science.gov (United States)

    Lucon, Enrico

    2007-08-01

    SCK·CEN has characterized the mechanical properties of several ferritic/martensitic steels, both unirradiated and irradiated. Fracture toughness has been evaluated using Charpy impact and fracture mechanics tests. Two safety-related features have emerged: (a) the applicability of the master curve approach (ASTM E1921-05) appears questionable; and (b) irradiation embrittlement is systematically larger when quantified in terms of quasi-static fracture toughness than when measured from Charpy tests. Both issues are examined in detail and possible interpretations are proposed; potential improvements given by the application of more advanced fracture toughness analysis methodologies are discussed. In order to clarify whether the Charpy/fracture toughness difference in embrittlement is due to loading rate effects, dynamic toughness tests have been performed in the unirradiated condition and for two irradiation doses (0.3 and 1.6 dpa). The corresponding dynamic T0 shifts have been compared with the shifts of Charpy and master curve quasi-static transition temperatures. Other possible contributions are examined and discussed.