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Sample records for charpy impact properties

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  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. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Validation Study of Unnotched Charpy and Taylor-Anvil Impact Experiments using Kayenta

    Energy Technology Data Exchange (ETDEWEB)

    Kamojjala, Krishna [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lacy, Jeffrey [Idaho National Lab. (INL), Idaho Falls, ID (United States); Chu, Henry S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Brannon, Rebecca [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    Validation of a single computational model with multiple available strain-to-failure fracture theories is presented through experimental tests and numerical simulations of the standardized unnotched Charpy and Taylor-anvil impact tests, both run using the same material model (Kayenta). Unnotched Charpy tests are performed on rolled homogeneous armor steel. The fracture patterns using Kayenta’s various failure options that include aleatory uncertainty and scale effects are compared against the experiments. Other quantities of interest include the average value of the absorbed energy and bend angle of the specimen. Taylor-anvil impact tests are performed on Ti6Al4V titanium alloy. The impact speeds of the specimen are 321 m/s and 393 m/s. The goal of the numerical work is to reproduce the damage patterns observed in the laboratory. For the numerical study, the Johnson-Cook failure model is used as the ductile fracture criterion, and aleatory uncertainty is applied to rate-dependence parameters to explore its effect on the fracture patterns.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  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. 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.

  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. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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...

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  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. 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...

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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 ...

  9. 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)

  10. 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.

  11. 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...

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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)

  1. 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.

  2. 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.

  3. 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.

  4. 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...

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Changes in the Material Properties of Steel 1.4762 Depending on the Temperature

    Science.gov (United States)

    Brnic, Josip; Turkalj, Goran; Krscanski, Sanjin; Niu, Jitai; Li, Qiang

    2016-09-01

    This paper presents the experimental results and analysis of the behaviour of steel 1.4762 at different temperatures. Tensile mechanical properties and creep behaviour were determined using uniaxial tests. Charpy impact test was used to determine impact energies at different temperatures. The mentioned mechanical properties are displayed as engineering stress-strain diagrams while material resistance to creep is presented in the form of creep curves. Based on Charpy impact energy an assessment of fracture toughness is given. Experimental results show that the values of mechanical properties are continuously decreased by increasing the temperature. After the temperature of 623 K (tensile strength: 468 MPa; yield strength: 298 MPa) the decrease of the ultimate strength and yield strength is especially emphasized and the difference between them becomes smaller. The creep resistance is considered quite small, except at low stress levels.

  14. 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.

  15. 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)

  16. 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.

  17. 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.

  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. The utilize of gamma radiation on the examination of mechanical properties of polymeric materials

    OpenAIRE

    F. Greškovič; Varga, J.; Ľ. Dulebová

    2012-01-01

    The article deals about the application area of radiation crosslinking of plastics, which follows after the injection moulding. The main objective of the presented article is the research of influence irradiation dosage on mechanical properties of materials: PP filled by 15 % of mineral filler – talc. Mechanical properties - tensile strength and impact strength by Charpy were examined in dependence on absorbed dose of the gamma rays on various conditions and were compared with non-irradiated ...

  20. 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.

  1. 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.)

  2. Impact properties of zinc die cast alloys

    Energy Technology Data Exchange (ETDEWEB)

    Schrems, Karol K.; Dogan, Omer N.; Manahan, M.P. (MPM Technologies, Inc.); Goodwin, F.E. (ILZRO)

    2005-01-01

    Alloys 3, 5, AcuZinc 5, and ZA-8 were tested at five temperatures between -40 C and room temperature to determine impact properties. Izod impact energy data was obtained in accordance with ASTM D256. Unlike ASTM E23, these samples were tested with a milled notch in order to compare with plastic samples. In addition, flexural data was obtained for design use.

  3. 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.

  4. 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.

  5. 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 ...

  6. 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.

  7. 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...

  8. 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...

  9. Effect of cladding procedures on mechanical properties of heat treated dissimilar joint

    Directory of Open Access Journals (Sweden)

    B. Mateša

    2012-10-01

    Full Text Available The specimens plated by different cladding procedures (hot rolling, submerged arc welding surfacing using strip electrode (SAW and explosion welding were heat treated by annealing (650 ºC through 2 hours. Charpy impact energy testing, as well as shear strength testing of clad joints were performed. Testing results indicated significance of cladding procedure and determined heat treatment infl uences on stated mechanical properties.

  10. 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)

  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. Mechanical properties of the as-forged and the forged-and-milled steels for reactor pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bong Sang; Yoon, Ji Hyun; Kim, Joo Hak; Oh, Yong Jun; Hong, Jun Hwa [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2001-04-01

    The mechanical properties of the as-forged and the forged and milled SA508-Gr.3 reactor pressure vessel steels were evaluated. The full Charpy impact curves obtained for four different locations in test materials. The various data including yield strengths, tensile strengths, elongations were obtained from the tensile strengths, elongations were obtained from the tensile test results for two locations in test materials. The detailed test results were integrated and analysed in this report. 6 refs., 7 figs., 5 tabs. (Author)

  13. 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.

  14. 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.

  15. 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.

  16. The effect of hot isostatic pressing on crack initiation, fatigue, and mechanical properties of two cast aluminum alloys

    Science.gov (United States)

    Rich, T. P.; Orbison, J. G.; Duncan, R. S.; Olivero, P. G.; Peterec, R. H.

    1999-06-01

    This article presents the results of an experimental materials testing program on the effect of hot isostatic pressing (HIP) on the crack initiation, fatigue, and mechanical properties of two cast aluminum alloys: AMS 4220 and 4225. These alloys are often used in castings for high temperature applications. Standard tensile and instrumented Charpy impact tests were performed at room and elevated temperatures. The resulting data quantify improvements in ultimate tensile strength, ductility, and Charpy impact toughness from the HIP process while indicating little change in yield strength for both alloys. In addition standard fracture mechanics fatigue tests along with a set of unique fatigue crack initiation tests were performed on the alloys. Hot isostatic pressing was shown to produce a significant increase in cycles to crack initiation for AMS 4225, while no change was evident in traditional da/dN fatigue crack growth. The data permits comparisons of the two alloys both with and without the HIP process.

  17. 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.

  18. 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

  19. 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.

  20. 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%.

  1. 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.

  2. Mechanical Properties of Isotactic Polypropylene Modified with Thermoplastic Potato Starch

    Science.gov (United States)

    Knitter, M.; Dobrzyńska-Mizera, M.

    2015-05-01

    In this paper selected mechanical properties of isotactic polypropylene (iPP) modified with potato starch have been presented. Thermoplastic starch (TPS) used as a modifier in the study was produced from potato starch modified with glycerol. Isotactic polypropylene/thermoplastic potato starch composites (iPP/TPS) that contained 10, 30, 50 wt.% of modified starch were examined using dynamic mechanical-thermal analysis, static tensile, Brinell hardness, and Charpy impact test. The studies indicated a distinct influence of a filler content on the mechanical properties of composites in comparison with non-modified polypropylene.

  3. 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.

  4. Effect of neutron irradiation on the mechanical properties of weld overlay cladding for reactor pressure vessel

    Science.gov (United States)

    Tobita, Tohru; Udagawa, Makoto; Chimi, Yasuhiro; Nishiyama, Yutaka; Onizawa, Kunio

    2014-09-01

    This study investigates the effects of high fluence neutron irradiation on the mechanical properties of two types of cladding materials fabricated using the submerged-arc welding and electroslag welding methods. The tensile tests, Charpy impact tests, and fracture toughness tests were conducted before and after the neutron irradiation with a fluence of 1 × 1024 n/m2 at 290 °C. With neutron irradiation, we could observe an increase in the yield strength and ultimate strength, and a decrease in the total elongation. All cladding materials exhibited ductile-to-brittle transition behavior during the Charpy impact tests. A reduction in the Charpy upper-shelf energy and an increase in the ductile-to-brittle transition temperature was observed with neutron irradiation. There was no obvious decrease in the elastic-plastic fracture toughness (JIc) of the cladding materials upon irradiation with high neutron fluence. The tearing modulus was found to decrease with neutron irradiation; the submerged-arc-welded cladding materials exhibited low JIc values at high temperatures.

  5. Effect of neutron irradiation on the mechanical properties of weld overlay cladding for reactor pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Tobita, Tohru, E-mail: tobita.tohru@jaea.go.jp; Udagawa, Makoto; Chimi, Yasuhiro; Nishiyama, Yutaka; Onizawa, Kunio

    2014-09-15

    This study investigates the effects of high fluence neutron irradiation on the mechanical properties of two types of cladding materials fabricated using the submerged-arc welding and electroslag welding methods. The tensile tests, Charpy impact tests, and fracture toughness tests were conducted before and after the neutron irradiation with a fluence of 1 × 10{sup 24} n/m{sup 2} at 290 °C. With neutron irradiation, we could observe an increase in the yield strength and ultimate strength, and a decrease in the total elongation. All cladding materials exhibited ductile-to-brittle transition behavior during the Charpy impact tests. A reduction in the Charpy upper-shelf energy and an increase in the ductile-to-brittle transition temperature was observed with neutron irradiation. There was no obvious decrease in the elastic–plastic fracture toughness (J{sub Ic}) of the cladding materials upon irradiation with high neutron fluence. The tearing modulus was found to decrease with neutron irradiation; the submerged-arc-welded cladding materials exhibited low J{sub Ic} values at high temperatures.

  6. 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)

  7. 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.

  8. 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.

  9. Grey water impact on soil physical properties

    Directory of Open Access Journals (Sweden)

    Miguel L. Murcia-Sarmiento

    2014-01-01

    Full Text Available Due to the increasing demand for food produced by the increase in population, water as an indispensable element in the growth cycle of plants every day becomes a fundamental aspect of production. The demand for the use of this resource is necessary to search for alternatives that should be evaluated to avoid potential negative impacts. In this paper, the changes in some physical properties of soil irrigated with synthetic gray water were evaluated. The experimental design involved: one factor: home water and two treatments; without treated water (T1 and treated water (T2. The variables to consider in the soil were: electrical conductivity (EC, exchangeable sodium percentage (ESP, average weighted diameter (MWD and soil moisture retention (RHS. The water used in drip irrigation high frequency was monitored by tensiometer for producing a bean crop (Phaseolous vulgaris L. As filtration system used was employed a unit composed of a sand filter (FLA and a subsurface flow wetland artificial (HFSS. The treatments showed significant differences in the PSI and the RHS. The FLA+HFSS system is an alternative to the gray water treatment due to increased sodium retention.

  10. 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.

  11. Fracture properties of neutron-irradiated martensitic 9Cr-WVTa steels below room temperature

    Science.gov (United States)

    Abe, F.; Narui, M.; Kayano, H.

    1994-09-01

    Fracture properties of the reduced activation martensitic 9Cr-1WVTa and 9Cr-3WVTa steels were investigated by carrying out instrumented Charpy impact tests and tensile tests at temperatures below room temperature after irradiation in the Japan Materials Testing Reactor at 493 and 538 K. Modified 9Cr-1MoVNb steel was also examined for comparison. The irradiation-induced increase in ductile-to-brittle transition temperature was 53, 26 and 40 K for the {1}/{3} size Charpy specimens of 9Cr-1WVTa, 9Cr-3WVTa and 9Cr-1MoVNb steels, respectively, which resulted primarily from the irradiation-induced increase in yield stress. The cleavage fracture stress was 1820-1870 MPa for the three steels in unirradiated conditions, which was scarcely affected by irradiation. The deflections to the maximum load and to the brittle fracture initiation were decreased by irradiation. In the tensile test, quasi-cleavage fracture occurred at 77 K in both unirradiated and irradiated conditions. The cleavage fracture stress was 1320-1380 MPa for the tensile specimens of the three steels, which was about 1.4 times smaller than that for the Charpy specimens.

  12. The utilize of gamma radiation on the examination of mechanical properties of polymeric materials

    Directory of Open Access Journals (Sweden)

    F. Greškovič

    2012-04-01

    Full Text Available The article deals about the application area of radiation crosslinking of plastics, which follows after the injection moulding. The main objective of the presented article is the research of influence irradiation dosage on mechanical properties of materials: PP filled by 15 % of mineral filler – talc. Mechanical properties - tensile strength and impact strength by Charpy were examined in dependence on absorbed dose of the gamma rays on various conditions and were compared with non-irradiated samples. Radiation processing involves mainly the use of either electron beams from electron accelerators or gamma radiation from Cobalt-60 sources.

  13. Mechanical, Thermal and Dynamic Mechanical Properties of PP/GF/xGnP Nanocomposites

    Science.gov (United States)

    Ashenai Ghasemi, F.; Ghorbani, A.; Ghasemi, I.

    2017-03-01

    The mechanical, thermal, and dynamic mechanical properties of ternary nanocomposites based on polypropylene, short glass fibers, and exfoliated graphene nanoplatelets were studied. To investigate the mechanical properties, uniaxial tensile and Charpy impact tests were carried out. To study the crystallinity of the compositions, a DSC test was performed. A dynamic mechanical analysis was used to characterize the storage modulus and loss factor (tan δ). The morphology of the composites was studied by a scanning electron microscope (SEM). The results obtained are presented in tables and graphics.

  14. Subtask 12A3: Fabrication and properties of compositional variants of vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Grossbeck, M.L.; Alexander, D.J.; Gubbi, A.N. [Oak Ridge National Lab., TN (United States)

    1995-03-01

    Procurement of five 15 kg heats of V-Cr-Ti alloys with variations in Cr and Ti concentrations from the primary V-4Cr-4Ti composition. Fabrication into sheet product, determination of the tensile and Charpy impact properties, and preparation of specimens for reactor irradiation experiments. Data obtained from these alloys will be used to define the allowable ranges of Cr and Ti within which consistent properties may be obtained. Four 15 kg heats with variations in Cr and Ti concentration have been procured in various plate and sheet thicknesses. Measurements of recovery and recrystallization kinetics, precipitation behavior, and Charpy impact properties are in progress to compare properties with the behavior of the primary alloy composition V-4Cr-4Ti. In the fully recrystallized condition, the impact properties of the V-6Cr-3Ti alloy are inferior to those of the 500 kg heat of V-4Cr-4Ti. However, properties comparable to those of the V-4Cr-4Ti can be obtained of the V-6Cr-3Ti as tested in a partially-recrystallized condition. 5 figs., 4 tabs.

  15. Electron impact phenomena and the properties of gaseous ions

    CERN Document Server

    Field, F H; Massey, H S W; Brueckner, Keith A

    1970-01-01

    Electron Impact Phenomena and the Properties of Gaseous Ions, Revised Edition deals with data pertaining to electron impact and to molecular gaseous ionic phenomena. This book discusses electron impact phenomena in gases at low pressure that involve low-energy electrons, which result in ion formation. The text also describes the use of mass spectrometers in electron impact studies and the degree of accuracy obtained when measuring electron impact energies. This book also reviews relatively low speed electrons and the transitions that result in the ionization of the atomic system. This text the

  16. 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.

  17. How property title impacts urban consolidation

    DEFF Research Database (Denmark)

    Easthope, Hazel; Warnken, Jan; Sherry, Cathy

    2014-01-01

    Continuing urbanisation is triggering an increase in multi-titled housing internationally. This trend has given rise to a substantial research interest in the social consequences of higher density living. Little enquiry, however, has been directed to examining how property title subdivisions...... tensions inherent in multi-title developments: i) tensions between individual and collective property rights, ii) tensions between the needs and responsibilities of different stakeholders, and iii) tensions inherent in the concurrent role of multi-title developments as governmental, market and civil...

  18. A Conceptual Framework of Green Certification Impact On Property Price

    Directory of Open Access Journals (Sweden)

    Abdullah Lizawati

    2016-01-01

    Full Text Available Green building is one of the sustainability dimensions in built environment. The issues of green building and its impact to the society have been increasingly discussed. Green certification is one of the components in measuring sustainable development and plays an important role as an assessment system to an individual building’s performance. The question arises whether the market understand and recognized the green certification. The objectives of this research are to discuss the issue pertaining to green value and the relationship between green certification and property price. The research emphasized on the understanding of property attributes focusing on green certification and the impact to the property price. Among the attributes identified are structural characteristics, location and neighborhood, and time attributes. Thus, this paper will discusses the review of literature on green development and the significance impact on property market in term of price and value. The green building development across the country could be classified as another sector in property markets that give significant impact to the real estate industry. As a result, a conceptual framework in assessing the impact of green certification is suggested to provide a significant input in developing the model of hedonic pricing for green building. This research may contribute to extend the body of knowledge in the area of green development and a suggested significant input will give much emphasize on the new valuation technique in valuing green building properties.

  19. Effects of hydrogen on mechanical properties of Cr-Mo steel equipment in refinery environments

    Energy Technology Data Exchange (ETDEWEB)

    Toussaint, P. [Industeel Belgium, Charleroi (Belgium); Pillot, S.; Bourges, P. [Industeel Creusot, Le Creusot (France). Centre de Reserche des Materiaux du Creusot; Masson, G. [ArcelorMittal Global Plates Strategy, Luxemboug (Luxembourg); Coudreuse, L. [Industeel Loire, Rive de Gier (France)

    2008-07-01

    This paper discussed an experimental study conducted to determine the effect of hydrogen on the mechanical properties of steel refinery pressure vessels. Hydrogen was introduced into the steel during service as well as during a shut-down operation in order to determine tensile and Charpy-impact properties of the base metal, heat-affected zone, and weld metal. Charpy impact transition curves were assessed in order to evaluate the effect of hydrogen content on the fracture aspect transition temperature (FATT). Tensile specimens were charged with hydrogen in an autoclave at temperatures lower than 450 degrees C. Creep tests were conducted to measure the variation of creep strength and ductility between specimens. The effect of hydrogen on different weld microstructures was examined. Results of the study showed that the FATT was increased by the presence of hydrogen in the metal. Sensitivities in the weld metal were noted. Tests conducted to examine the influence of hydrogen on creep properties demonstrated that the presence of hydrogen reduced rupture times. Hydrogen affected the static, quasi-static, and dynamic properties of the steel samples. It was concluded that vanadium alloyed materials are less sensitive to hydrogen than standard steel grades. 3 refs., 9 tabs., 11 figs.

  20. Narrow groove gas tungsten arc welding of ASTM A508 Class 4 steel for improved toughness properties

    Energy Technology Data Exchange (ETDEWEB)

    Penik, M.A. Jr. [Rensselaer Polytechnic Inst., Troy, NY (United States)

    1997-04-01

    Welding of heavy section steel has traditionally used the automatic submerged arc welding (ASAW) process because of the high deposition rates achievable. However, the properties, particularly fracture toughness, of the weld are often inferior when compared to base material. This project evaluated the use of narrow groove gas tungsten arc welding (GTAW) to improve weld material properties. The welding procedures were developed for ASTM A508 Class 4 base material using a 1% Ni filler material complying to AWS Specification A.23-90-EF3-F3-N. A narrow groove joint preparation was used in conjunction with the GTAW process so competitive fabrication rates could be achieved when compared to the ASAW process. Weld procedures were developed to refine weld substructure to achieve better mechanical properties. Two heaters of weld wire were used to examine the effects of minor filler metal chemistry differences on weld mechanical properties. Extensive metallographic evaluations showed excellent weld quality with a refined microstructure. Chemical analysis of the weld metal showed minimal weld dilution by the base metal. Mechanical testing included bend and tensile tests to ensure weld quality and strength. A Charpy impact energy curve versus temperature and fracture toughness curve versus temperature were developed for each weld wire heat. Results of fracture toughness and Charpy impact testing indicated an improved transition temperature closer to that of the base material properties.

  1. 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.

  2. 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

  3. 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.

  4. Recent Impacts on Mars: Cluster Properties and Seismic Signal Predictions

    Science.gov (United States)

    Justine Daubar, Ingrid; Schmerr, Nicholas; Banks, Maria; Marusiak, Angela; Golombek, Matthew P.

    2016-10-01

    Impacts are a key source of seismic waves that are a primary constraint on the formation, evolution, and dynamics of planetary objects. Geophysical missions such as InSight (Banerdt et al., 2013) will monitor seismic signals from internal and external sources. New martian craters have been identified in orbital images (Malin et al., 2006; Daubar et al., 2013). Seismically detecting such impacts and subsequently imaging the resulting craters will provide extremely accurate epicenters and source crater sizes, enabling calibration of seismic velocities, the efficiency of impact-seismic coupling, and retrieval of detailed regional and local internal structure.To investigate recent impact-induced seismicity on Mars, we have assessed ~100 new, dated impact sites. In approximately half of new impacts, the bolide partially disintegrates in the atmosphere, forming multiple craters in a cluster. We incorporate the resulting, more complex, seismic effects in our model. To characterize the variation between sites, we focus on clustered impacts. We report statistics of craters within clusters: diameters, morphometry indicating subsurface layering, strewn-field azimuths indicating impact direction, and dispersion within clusters indicating combined effects of bolide strength and elevation of breakup.Measured parameters are converted to seismic predictions for impact sources using a scaling law relating crater diameter to the momentum and source duration, calibrated for impacts recorded by Apollo (Lognonne et al., 2009). We use plausible ranges for target properties, bolide densities, and impact velocities to bound the seismic moment. The expected seismic sources are modeled in the near field using a 3-D wave propagation code (Petersson et al., 2010) and in the far field using a 1-D wave propagation code (Friederich et al., 1995), for a martian seismic model. Thus we calculate the amplitudes of seismic phases at varying distances, which can be used to evaluate the detectability

  5. Comparison of Impact Properties for Carbon and Low Alloy Steels

    Institute of Scientific and Technical Information of China (English)

    O.H. Ibrahim

    2011-01-01

    The impact properties of hot rolled carbon steel (used for the manufacture of reinforcement steel bars) and the quenched & tempered (Q&T) low alloy steel (used in the pressure vessel industry) were determined. The microstructure of the hot rolled carbon steel contained ferrite/pearlite phases, while that of the quenched and tempered low alloy steel contained bainite structure. Impact properties were determined for both steels by instrumented impact testing at temperatures between -150 and 200℃. The impact properties comprised total impact energy, ductile to brittle transition temperature, crack initiation and propagation energy, brittleness transition temperature and cleavage fracture stress. The Q&T low alloy steel displayed much higher resistance to ductile fracture at high test temperatures, while its resistance to brittle fracture at low test temperatures was a little higher than that of the hot rolled carbon steel. The results were discussed in relation to the difference in the chemical composition and microstructure for the two steels.

  6. 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...

  7. Effect of mold temperature on short and long-term mechanical properties of PBT

    Directory of Open Access Journals (Sweden)

    2008-02-01

    Full Text Available In this work, the effect of mold temperature variation on the short-term mechanical properties obtained from the tensile and Charpy impact tests, and the long-term mechanical properties obtained from dynamic mechanical loading and flexural creep of injection molded polybutylene terepthalate (PBT are reported. It has been observed that the effect of changing the processing condition viz. mold temperature on the viscoelastic properties are more pronounced when their long-term behavior is tested. The tensile and impact properties showed only a negligible effect to the change in mold temperature. Further, analysis of the creep curves by applying a four-element Burger model presented a comprehensive understanding of their long-term viscoelastic behavior with respect to the change in mold temperature.

  8. 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.

  9. Effect of Beam Oscillation on Microstructure and Mechanical Properties of AISI 316L Electron Beam Welds

    Science.gov (United States)

    Kar, Jyotirmaya; Roy, Sanat Kumar; Roy, Gour Gopal

    2017-04-01

    The properties of electron beam-welded AISI 316L stainless steel butt joints prepared with and without beam oscillation were evaluated by microstructural analysis, mechanical testing like microhardness measurements, tensile tests at room and elevated temperature 973 K (700 °C), three-point bend, and Charpy impact tests. All joints, irrespective of being prepared with or without beam oscillation, were found to be defect free. Welds produced by beam oscillation exhibited narrower fusion zone (FZ) with lathy ferrite morphology, while the weld without beam oscillation was characterized by wider FZ and skeletal ferrite morphology. During tensile tests at room and elevated temperature 973 K (700 °C), all samples fractured in the base metal (BM) and showed almost the same tensile properties as that of the BM. However, the notch tensile tests at room temperature demonstrated higher strength for joints prepared with the oscillating beam. Besides, face and root bend tests, as well as Charpy impact tests, showed higher bending strength and notch toughness, respectively, for joints prepared with beam oscillation.

  10. Effect of Beam Oscillation on Microstructure and Mechanical Properties of AISI 316L Electron Beam Welds

    Science.gov (United States)

    Kar, Jyotirmaya; Roy, Sanat Kumar; Roy, Gour Gopal

    2017-02-01

    The properties of electron beam-welded AISI 316L stainless steel butt joints prepared with and without beam oscillation were evaluated by microstructural analysis, mechanical testing like microhardness measurements, tensile tests at room and elevated temperature 973 K (700 °C), three-point bend, and Charpy impact tests. All joints, irrespective of being prepared with or without beam oscillation, were found to be defect free. Welds produced by beam oscillation exhibited narrower fusion zone (FZ) with lathy ferrite morphology, while the weld without beam oscillation was characterized by wider FZ and skeletal ferrite morphology. During tensile tests at room and elevated temperature 973 K (700 °C), all samples fractured in the base metal (BM) and showed almost the same tensile properties as that of the BM. However, the notch tensile tests at room temperature demonstrated higher strength for joints prepared with the oscillating beam. Besides, face and root bend tests, as well as Charpy impact tests, showed higher bending strength and notch toughness, respectively, for joints prepared with beam oscillation.

  11. Characterization of the Microstructures and the Cryogenic Mechanical Properties of Electron Beam Welded Inconel 718

    Science.gov (United States)

    Kwon, Soon Il; Bae, Sang Hyun; Do, Jeong Hyeon; Jo, Chang Yong; Hong, Hyun Uk

    2016-02-01

    The microstructures and the cryogenic mechanical properties of electron beam (EB) welds between cast and forged Inconel 718 superalloys with a thickness of 10 mm were investigated in comparison with gas tungsten arc (GTA) welds. EB welding with a heat input lower than 250 J/mm caused the formation of liquation microfissuring in the cast-side heat-affected-zone (HAZ) of the EB welds. HAZ liquation microfissuring appeared to be associated with the constitutional liquation of primary NbC carbides at the grain boundaries. Compared with the GTA welding process, the EB welding produced welds with superior microstructure, exhibiting fine dendritic structure associated with the reduction in size and fraction of the Laves phase due to the rapid cooling rate. This result was responsible for the superior mechanical properties of the EB welds at 77 K (-196 °C). Laves particles in both welds were found to provide the preferential site for the crack initiation and propagation, leading to a significant decrease in the Charpy impact toughness at 77 K (-196 °C). Crack initiation and propagation induced by Charpy impact testing were discussed in terms of the dendrite arm spacing, the Laves size and the dislocation structure ahead of the crack arisen from the fractured Laves phase in the two welds.

  12. 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.

  13. 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.

  14. Method for Investigation of Frictional Properties at Impact Loading

    Science.gov (United States)

    Sundin, K. G.; Åhrström, B. O.

    1999-05-01

    In the assessment of lubricant performance and also in various other contact applications it is of importance to know the frictional qualities of a surface. Under quasi-static conditions, normal and frictional forces are measured using force transducers but the task is more difficult when loads are transient. The experimental method presented in this paper is based on the analysis of propagating waves in a beam, due to an impact on the end surface. The impact is oblique and therefore a transverse as well as a normal force is generated. The normal force history is measured from the axial non-dispersive wave using strain gauges. Transverse force and bending moment both generate dispersive flexural waves. From the FFT of two transverse acceleration histories, the frictional force at the end of the rod is evaluated using beam theory. The relation between normal and frictional force histories displays the frictional properties at the impact. Preliminary results are presented.

  15. Asteroid Impact Deflection and Assessment (AIDA) mission - Properties of Impact Ejecta

    Science.gov (United States)

    Hamilton, Douglas P.; Fahnestock, Eugene G.; Schwartz, Stephen R.; Murdoch, Naomi; Asphaug, Erik; Cheng, Andrew F.; Housen, Kevin R.; Michel, Patrick; Miller, Paul L.; Stickle, Angela; Tancredi, Gonzalo; Vincent, Jean-Baptiste; Wuennemann, Kai; Yu, Yang; AIDA Impact Simulation Working Group

    2016-10-01

    The Asteroid Impact Deflection and Assessment (AIDA) mission is composed of NASA's Double Asteroid Redirection Test (DART) mission and ESA's Asteroid Impact Monitor (AIM) rendezvous mission. The DART spacecraft is designed to impact the small satellite of near-Earth asteroid 65803 Didymos in October 2022, while the in-situ AIM spacecraft observes. AIDA's Modeling and Simulation of Impact Outcomes Working Group is tasked with investigating properties of the debris ejected from the impact. The orbital evolution of this ejecta has important implications for observations that the AIM spacecraft will take as well as for the safety of the spacecraft itself. Ejecta properties including particle sizes, bulk densities, and velocities all depend on the poorly-known physical properties of Didymos' moon. The moon's density, internal strength, and especially its porosity have a strong effect on all ejecta properties. Making a range of assumptions, we perform a suite of numerical simulations to determine the fate of the ejected material; we will use simulation predictions to optimize AIM observations and safety. Ultimately, combining AIM's observations of the ejecta with detailed numerical simulations will help constrain key satellite parameters.We use distinct types of numerical tools to explore ejecta properties based on additional target parameters (different forms of friction, cohesion), e.g., the shock physics code iSALE, smoothed particle hydrodynamics codes, and the granular code PKDGRAV. Given the large discrepancy between the 6 km/s impact speed of DART and the moon's 6 cm/s escape speed, a great challenge will be to determine properties of the low-speed ejecta. Very low-speed material relevant to the safety of the AIM spacecraft and its ability to conduct its observations may loft from the crater at late stages of the impact process, or from other locations far from the impact site due to seismic energy propagation. The manner in which seismic waves manifests in

  16. Characterization of Triaxial Braided Composite Material Properties for Impact Simulation

    Science.gov (United States)

    Roberts, Gary D.; Goldberg, Robert K.; Biniendak, Wieslaw K.; Arnold, William A.; Littell, Justin D.; Kohlman, Lee W.

    2009-01-01

    The reliability of impact simulations for aircraft components made with triaxial braided carbon fiber composites is currently limited by inadequate material property data and lack of validated material models for analysis. Improvements to standard quasi-static test methods are needed to account for the large unit cell size and localized damage within the unit cell. The deformation and damage of a triaxial braided composite material was examined using standard quasi-static in-plane tension, compression, and shear tests. Some modifications to standard test specimen geometries are suggested, and methods for measuring the local strain at the onset of failure within the braid unit cell are presented. Deformation and damage at higher strain rates is examined using ballistic impact tests on 61- by 61- by 3.2-mm (24- by 24- by 0.125-in.) composite panels. Digital image correlation techniques were used to examine full-field deformation and damage during both quasi-static and impact tests. An impact analysis method is presented that utilizes both local and global deformation and failure information from the quasi-static tests as input for impact simulations. Improvements that are needed in test and analysis methods for better predictive capability are examined.

  17. Analysis of Dynamic Properties of Piezoelectric Structure under Impact Load

    Directory of Open Access Journals (Sweden)

    Taotao Zhang

    2015-10-01

    Full Text Available An analytical model of the dynamic properties is established for a piezoelectric structure under impact load, without considering noise and perturbations in this paper. Based on the general theory of piezo-elasticity and impact mechanics, the theoretical solutions of the mechanical and electrical fields of the smart structure are obtained with the standing and traveling wave methods, respectively. The comparisons between the two methods have shown that the standing wave method is better for studying long-time response after an impact load. In addition, good agreements are found between the theoretical and the numerical results. To simulate the impact load, both triangle and step pulse loads are used and comparisons are given. Furthermore, the influence of several parameters is discussed so as to provide some advices for practical use. It can be seen that the proposed analytical model would benefit, to some extent, the design and application (especially the airport runway of the related smart devices by taking into account their impact load performance.

  18. 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.

  19. 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。

  20. Effect of Heat Treatment Process on Mechanical Properties and Microstructure of a 9% Ni Steel for Large LNG Storage Tanks

    Science.gov (United States)

    Zhang, J. M.; Li, H.; Yang, F.; Chi, Q.; Ji, L. K.; Feng, Y. R.

    2013-12-01

    In this paper, two different heat treatment processes of a 9% Ni steel for large liquefied natural gas storage tanks were performed in an industrial heating furnace. The former was a special heat treatment process consisting of quenching and intercritical quenching and tempering (Q-IQ-T). The latter was a heat treatment process only consisting of quenching and tempering. Mechanical properties were measured by tensile testing and charpy impact testing, and the microstructure was analyzed by optical microscopy, transmission electron microscopy, and x-ray diffraction. The results showed that outstanding mechanical properties were obtained from the Q-IQ-T process in comparison with the Q-T process, and a cryogenic toughness with charpy impact energy value of 201 J was achieved at 77 K. Microstructure analysis revealed that samples of the Q-IQ-T process had about 9.8% of austenite in needle-like martensite, while samples of the Q-T process only had about 0.9% of austenite retained in tempered martensite.

  1. Impacts of land leveling on lowland soil physical properties

    Directory of Open Access Journals (Sweden)

    José Maria Barbat Parfitt

    2014-02-01

    Full Text Available The practice of land leveling alters the soil surface to create a uniform slope to improve land conditions for the application of all agricultural practices. The aims of this study were to evaluate the impacts of land leveling through the magnitudes, variances and spatial distributions of selected soil physical properties of a lowland area in the State of Rio Grande do Sul, Brazil; the relationships between the magnitude of cuts and/or fills and soil physical properties after the leveling process; and evaluation of the effect of leveling on the spatial distribution of the top of the B horizon in relation to the soil surface. In the 0-0.20 m layer, a 100-point geo-referenced grid covering two taxonomic soil classes was used in assessment of the following soil properties: soil particle density (Pd and bulk density (Bd; total porosity (Tp, macroporosity (Macro and microporosity (Micro; available water capacity (AWC; sand, silt, clay, and dispersed clay in water (Disp clay contents; electrical conductivity (EC; and weighted average diameter of aggregates (WAD. Soil depth to the top of the B horizon was also measured before leveling. The overall effect of leveling on selected soil physical properties was evaluated by paired "t" tests. The effect on the variability of each property was evaluated through the homogeneity of variance test. The thematic maps constructed by kriging or by the inverse of the square of the distances were visually analyzed to evaluate the effect of leveling on the spatial distribution of the properties and of the top of the B horizon in relation to the soil surface. Linear regression models were fitted with the aim of evaluating the relationship between soil properties and the magnitude of cuts and fills. Leveling altered the mean value of several soil properties and the agronomic effect was negative. The mean values of Bd and Disp clay increased and Tp, Macro and Micro, WAD, AWC and EC decreased. Spatial distributions of all

  2. EVALUATION OF THE IMPACT OF THIN POURS ON SALTSTONE PROPERTIES

    Energy Technology Data Exchange (ETDEWEB)

    Cozzi, A.; Langton, C.; Fox, K.

    2012-10-02

    testing showed increased flow when the number of cold joints was increased. Compressive strength testing showed that the maximum load at the onset of cracking was reduced by approximately 26% for those samples that contained cold joints as compared to the monolithic samples. The number of cold joints in the sample had no significant impact on the maximum load prior to cracking. The porosity of the samples was not influenced by cold joints. This result was expected as the porosity is a material property affected by the properties of the components (premix and salt solution) and the water to premix ratio. Overall, the only obvious impact of cold joints in the samples was to significantly increase hydraulic conductivity in the direction parallel to the cold joints. An increasing number of cold joints (thin layers) in the simulated saltstone samples did not exacerbate this effect, nor did it have a negative impact on the Leachability Indices or porosity for surfaces exposed for approximately four days. The presence of a cold joint reduced the compressive strength of the material, although this impact was seen regardless of the number of cold joints in the sample.

  3. IMPACT OF COOKING HOMOGENEITY ON PULP STRENGTH PROPERTIES

    Institute of Scientific and Technical Information of China (English)

    BofengMao

    2004-01-01

    Cooking homogeneity of kraft pulping can havesignificant impact on pulp strength properties. Wehave studied cooking homogeneity of two kraftdigesters within Stora Enso. One of the digesters is aone-vessel hydraulic continuous digester (digester A)and the other one is a two-vessel vapor/liquor phasecontinuous digester (digester B). They are located inthe same mill and use the same softwood chipquality. Due to the differences in chip pre-steamingand cooking facilities and conditions, significantdifferences in pulp strength properties, reject contentsand kappa variations have been found between thepulps produced in the two digesters. Digester A has amodem chip bin with efficient pre-heating and airremoval, whereas digester B has poor chippre-steaming conditions. Our strength deliverystudies show that although the two digesters producepulps with the same kappa number and viscosity, thepulp produced in digester A has about 20% higherstrength delivery, l%-unit (based on wood) lowerreject content and lower kappa variations based onFTIR spectra analysis on pulp sheet than the pulpproduced in digester B.Results of the studies indicate that morehomogeneous cooking,variation in the fibers,i.e., lower lignin/kappa leads to improved pulpstrength properties. Efficient chip pre-steaming isimportant/essential for achieving homogeneouscooking. Rebuilding the equipment for improvingchip pre-steaming conditions of digester B is to becarded out.

  4. IMPACT OF COOKING HOMOGENEITY ON PULP STRENGTH PROPERTIES

    Institute of Scientific and Technical Information of China (English)

    Bofeng Mao

    2004-01-01

    Cooking homogeneity of kraft pulping can have significant impact on pulp strength properties. We have studied cooking homogeneity of two kraft digesters within Stora Enso. One of the digesters is a one-vessel hydraulic continuous digester (digester A)and the other one is a two-vessel vapor/liquor phase continuous digester (digester B). They are located in the same mill and use the same softwood chip quality. Due to the differences in chip pre-steaming and cooking facilities and conditions, significant differences in pulp strength properties, reject contents and kappa variations have been found between the pulps produced in the two digesters. Digester A has a modem chip bin with efficient pre-heating and air removal, whereas digester B has poor chip pre-steaming conditions. Our strength delivery studies show that although the two digesters produce pulps with the same kappa number and viscosity, the pulp produced in digester A has about 20% higher strength delivery, l%-unit (based on wood) lower reject content and lower kappa variations based on FTIR spectra analysis on pulp sheet than the pulp produced in digester B.Results of the studies indicate that more homogeneous cooking, i.e., lower lignin/kappa variation in the fibers, leads to improved pulp strength properties. Efficient chip pre-steaming is important/essential for achieving homogeneous cooking. Rebuilding the equipment for improving chip pre-steaming conditions of digester B is to be carried out.

  5. Influence of the composition and heat treatments in the mechanical properties of aluminium bronze alloys; Influencia de la composicion y el tratamiento termico en las propiedades mecanicas de aleaciones de bronce al aluminio

    Energy Technology Data Exchange (ETDEWEB)

    Cenoz-Echeverria, I.; Fernandez-Carrasquilla, J.

    2007-07-01

    Aluminium bronzes are copper-base alloys containing aluminium within the limits between 5-12%. Additions of Fe, Ni and Mn are used as alloying elements forming a family of complex alloys noted for their exceptional strength and corrosion resistance. In present paper sd the Ni:Fe ratio and heat treatments have been analyzed by determining the mechanical properties for three different aluminium bronze alloys containing Cu-Al10-Fe3, Cu-Al10-Fe5-Ni5 and Cu-Al10-Fe4-Ni8. The effect of as cast, quenched and quenched and tempered structures has been investigated regarding hardness, proof and ultimate tensile strength, elongation, modules of elasticity, Poisson ratio, fracture toughness, fatigue strength, crack propagation and Charpy impact properties. The influence of temperature has been studied by testing the elastic modules, Poisson ratio, the proof stress, tensile strength and the Charpy impact properties at -20 degree centigree, 24 degree centigree and 100 degree centigree. (Author)

  6. 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.

  7. Effect of fibre orientations on the mechanical properties of kenaf–aramid hybrid composites for spall-liner application

    Institute of Scientific and Technical Information of China (English)

    R. YAHAYA; S.M. SAPUAN; M. JAWAID; Z. LEMAN; E.S. ZAINUDIN

    2016-01-01

    This paper presents the effect of kenaf fibre orientation on the mechanical properties of kenaf–aramid hybrid composites for military vehicle's spall liner application. It was observed that the tensile strength of woven kenaf hybrid composite is almost 20.78%and 43.55%higher than that of UD and mat samples respectively. Charpy impact strength of woven kenaf composites is 19.78%and 52.07%higher than that of UD and mat kenaf hybrid composites respectively. Morphological examinations were carried out using scanning electron microscopy. The results of this study indicate that using kenaf in the form of woven structure could produce a hybrid composite material with high tensile strength and impact resistance properties.

  8. Economic impact of fuel properties on turbine powered business aircraft

    Science.gov (United States)

    Powell, F. D.

    1984-01-01

    The principal objective was to estimate the economic impact on the turbine-powered business aviation fleet of potential changes in the composition and properties of aviation fuel. Secondary objectives include estimation of the sensitivity of costs to specific fuel properties, and an assessment of the directions in which further research should be directed. The study was based on the published characteristics of typical and specific modern aircraft in three classes; heavy jet, light jet, and turboprop. Missions of these aircraft were simulated by computer methods for each aircraft for several range and payload combinations, and assumed atmospheric temperatures ranging from nominal to extremely cold. Five fuels were selected for comparison with the reference fuel, nominal Jet A. An overview of the data, the mathematic models, the data reduction and analysis procedure, and the results of the study are given. The direct operating costs of the study fuels are compared with that of the reference fuel in the 1990 time-frame, and the anticipated fleet costs and fuel break-even costs are estimated.

  9. Impact of soil properties on selected pharmaceuticals adsorption in soils

    Science.gov (United States)

    Kodesova, Radka; Kocarek, Martin; Klement, Ales; Fer, Miroslav; Golovko, Oksana; Grabic, Roman; Jaksik, Ondrej

    2014-05-01

    The presence of human and veterinary pharmaceuticals in the environment has been recognized as a potential threat. Pharmaceuticals may contaminate soils and consequently surface and groundwater. Study was therefore focused on the evaluation of selected pharmaceuticals adsorption in soils, as one of the parameters, which are necessary to know when assessing contaminant transport in soils. The goals of this study were: (1) to select representative soils of the Czech Republic and to measure soil physical and chemical properties; (2) to measure adsorption isotherms of selected pharmaceuticals; (3) to evaluate impact of soil properties on pharmaceutical adsorptions and to propose pedotransfer rules for estimating adsorption coefficients from the measured soil properties. Batch sorption tests were performed for 6 selected pharmaceuticals (beta blockers Atenolol and Metoprolol, anticonvulsant Carbamazepin, and antibiotics Clarithromycin, Trimetoprim and Sulfamethoxazol) and 13 representative soils (soil samples from surface horizons of 11 different soil types and 2 substrates). The Freundlich equations were used to describe adsorption isotherms. The simple correlations between measured physical and chemical soil properties (soil particle density, soil texture, oxidable organic carbon content, CaCO3 content, pH_H2O, pH_KCl, exchangeable acidity, cation exchange capacity, hydrolytic acidity, basic cation saturation, sorption complex saturation, salinity), and the Freundlich adsorption coefficients were assessed using Pearson correlation coefficient. Then multiple-linear regressions were applied to predict the Freundlich adsorption coefficients from measured soil properties. The largest adsorption was measured for Clarithromycin (average value of 227.1) and decreased as follows: Trimetoprim (22.5), Metoprolol (9.0), Atenolol (6.6), Carbamazepin (2.7), Sulfamethoxazol (1.9). Absorption coefficients for Atenolol and Metoprolol closely correlated (R=0.85), and both were also

  10. Weld-metal property optimization from flux ingredients through mixture experiments and mathematical programming approach

    Directory of Open Access Journals (Sweden)

    Ademola David Adeyeye

    2009-09-01

    Full Text Available This paper presents a new methodology for weld-metal properties optimization from welding flux ingredients. The methodology integrates statistical design of mixture experiment with mathematical programming optimization technique. The mixture experiment is responsible for the modeling of the weld-metal properties as a function of welding flux levels while mathematical programming optimizes the model. Data and confirmed models from the literature were used to perform optimization on the responses. The maximum values possible with the prevailing conditions for acicular ferrite, charpy impact toughness and silicon transfer are 51.2%, 29 J and 0.231% respectively while the minimum oxygen content possible is 249 ppm. The new methodology is able to eliminate the limitations associated with the traditional experimental optimization methodology for flux formulation.

  11. 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.

  12. Impact of temperature on the biological properties of soil

    Science.gov (United States)

    Borowik, Agata; Wyszkowska, Jadwiga

    2016-01-01

    The aim of the study was to determine the response of soil microorganisms and enzymes to the temperature of soil. The effect of the temperatures: 5, 10, 15, 20, and 25°C on the biological properties of soil was investigated under laboratory conditions. The study was performed using four different soils differing in their granulometric composition. It was found that 15°C was the optimal temperature for the development of microorganisms in soil. Typically, in the soil, the highest activity of dehydrogenases was observed at 10-15°C, catalase and acid phosphatase - at 15°C, alkaline phosphatase at 20°C, urease and β-glucosidase at 25°C. The highest colony development index for heterotrophic bacteria was recorded in soils incubated at 25°C, while for actinomycetes and fungi at 15°C. The incubation temperature of soil only slightly changed the ecophysiological variety of the investigated groups of microorganisms. Therefore, the observed climate changes might have a limited impact on the soil microbiological activity, because of the high ability of microorganisms to adopt. The response of soil microorganisms and enzymes was more dependent on the soil granulometric composition, organic carbon, and total nitrogen than on its temperature.

  13. Impact behaviour of nylon-rubber blends: 5. Influence of the mechanical properties of the elastomer

    OpenAIRE

    Borggreve, R.J.M.; Gaymans, R.J.; Schuijer, J.

    1989-01-01

    Blends of 90wt% nylon-6 and 10wt% impact modifier were prepared. As impact modifiers were used: EPDM (ethylene propylene diene monomer) rubber, EPM (ethylene propylene monomer) rubber, polyethylene, four poly(ether esters) and some commercial impact modifers. EPDM, EPM and polyethylene were functionalized with maleic anhydride. The mechanical properties of the impact modifiers were tested with both a torsion pendulum test and a tensile test. The notched impact strength of the blends was measu...

  14. IMPACT OF INCREASED ALUMINATE CONCENTRATIONS ON PROPERTIES OF SALTSTONE MIXES

    Energy Technology Data Exchange (ETDEWEB)

    Harbour, J; Tommy Edwards, T; Erich Hansen, E; Vickie Williams, V

    2007-10-12

    One of the goals of the Saltstone variability study is to identify the operational and compositional variables that control or influence the important processing and performance properties of Saltstone mixes. The protocols developed in this variability study are ideally suited as a tool to assess the impact of proposed changes to the processing flow sheet for Liquid Waste Operations (LWO). One such proposal that is currently under consideration is to introduce a leaching step in the treatment of the High Level Waste (HLW) sludge to remove aluminum prior to vitrification at the Defense Waste Processing Facility (DWPF). This leachate would significantly increase the soluble aluminate concentrations as well as the free hydroxide ion concentration in the salt feed that will be processed at the Saltstone Processing Facility (SPF). Consequently, an initial study of the impact of increased aluminate concentration on the Saltstone grout properties was performed. The projected compositions and ranges of the aluminate rich salt stream (which includes the blending strategy) are not yet available and consequently, in this initial report, two separate salt stream compositions were investigated. The first stream starts with the previously projected baseline composition of the salt solution that will be fed to SPF from the Salt Waste Processing Facility (SWPF). The second stream is the solution that results from washing of the current Tank 51 sludge and subsequent transfer of the salt solution to Tank 11. The SWPF simulant has higher nitrate and lower free hydroxide than the Tank 11 simulant. In both of these cases, the aluminate was varied up to a maximum of 0.40 to 0.45M aluminate in order to evaluate the impact of increasing aluminate ion concentration on the grout properties. In general, the fresh grout properties of mixes made with SWPF and Tank 11 simulants were relatively insensitive to an increase in aluminate concentration in the salt solutions. However, the overall

  15. 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...

  16. Polypropylene–rubber blends: 1. The effect of the matrix properties on the impact behaviour

    NARCIS (Netherlands)

    Wal, van der A.; Mulder, J.J.; Oderkerk, J.; Gaymans, R.J.

    1998-01-01

    The effect of matrix properties, i.e. crystallinity and molecular weight, on the impact behaviour of polypropylene–EPDM blends was studied. The blends were made on a twin-screw extruder. The impact strength was determined as a function of temperature, using a notched Izod impact test. The matrix cry

  17. Effect of Heat Treatment on Microstructure, Mechanical Properties and Fracture Behaviour of Ship and Dual Phase Steels%Effect of Heat Treatment on Microstructure, Mechanical Properties and Fracture Behaviour of Ship and Dual Phase Steels

    Institute of Scientific and Technical Information of China (English)

    Fatih Hayat; Htiseyin Uzun

    2011-01-01

    Grade A (GA) and high strength steel DH36 ship steels possessing different chemical compositions were used, and strength properties of GA steel and DH36 steel were compared. Additionally, 4 types of dual phase (DP) steels with different martensite volume fractions (MVFs) were produced from GA steel by means of heat treatment and they were compared with other steels through conducting mierostructure, microhardness, tensile and impact tests. The fracture surfaces of specimens (DH36, GA and DP steels) exposed to tensile and Charpy impact tests were investigated by scanning electron microscope. Furthermore, it was found that the specimens quenched from 800 and 900℃ had better strength than DH36 steel. The tensile test results indicated that the tensile strength of DP steel water quenched from 900℃ was 3 times that of GA steel and twice that of DH36 steel.

  18. 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

  19. Impact of Intellectual Property in National and Business Development under the Context of the Current Globalization

    Directory of Open Access Journals (Sweden)

    Stalin Ballesteros García

    2016-12-01

    Full Text Available The objective of the document is to show the impact of the intellectual property on the national and enterprise development in the globalization context since the early twenty-first century. First, it is a historical telling of the intellectual property and its role in the international society; then outlining the arguments to infer the incidence degree of the intellectual property in the economic development of countries and then discussing the inclusion impact of concepts directly related to the intellectual property in business growth activities. It concludes with a reflection on the Colombian situation, in public and private context, in terms of intellectual property.

  20. Microstructure and mechanical properties of railway wheels manufactured with low-medium carbon Si-Mn-Mo-V steel

    Institute of Scientific and Technical Information of China (English)

    Mingru Zhang; Haicheng Gu

    2008-01-01

    The suitability of carbide-free bainite steel as railway wheel materials was investigated. The low-medium carbon Si-Mn-Mo-V steel was designed to make railway wheels by forging and rolling. The slack quenching with water was conducted on the tread of rim section by programmed control to simulate isothermal heat treatment after being austenitized. Microstructures and mechanical properties have been studied. The results indicate that the microstructure of the rim is mainly carbide-free bainite, and the mixed mi- crostructure of bainitic ferrite and granular bainite is observed in web and hub. The mechanical properties are superior to both the standard requirements and the commercial production, such as CL60 plain carbon. The Charpy impact energy is relatively high at room and/or subzero temperatures. The force-displacement curves and fractographies reveal the excellent ability of resistance to crack initiation and propagation.

  1. 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.

  2. 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.)

  3. IMPACT PROPERTIES OF METALLOCENE-CATALYZED ETHYLENE-α-OLEFIN COPOLYMERS

    Institute of Scientific and Technical Information of China (English)

    Xu-rong Xu; Jun-ting Xua; Lin-xian Feng

    2002-01-01

    The impact properties of two selected metallocene-catalyzed ethylene-butene copolymers and one conventional copolymer were evaluated using Izod impact test. It is found that the metallocene-catalyzed copolymer shows superior impact properties. This result was explained on the basis of the more homogeneous inter-molecular composition distribution and narrower molecular weight distribution, which leads to more homogeneous morphology with fewer defects. Stepwise crystallization improves the impact properties, especially in the crack propagation process, to a large extent. This is due to the decrease of entanglements by stepwise crystallization, which is advantageous for the chain slip and shear. The polymer with heterogeneous intra-molecular composition distribution exhibits a more evident improvement of impact properties under stepwise crystallization.

  4. Impact properties of aluminium - glass fiber reinforced plastics sandwich panels

    Directory of Open Access Journals (Sweden)

    Mathivanan Periasamy

    2012-06-01

    Full Text Available Aluminium - glass fiber reinforced plastics (GFRP sandwich panels are hybrid laminates consisting of GFRP bonded with thin aluminum sheets on either side. Such sandwich materials are increasingly used in airplane and automobile structures. Laminates with varying aluminium thickness fractions, fiber volume fractions and orientation in the layers of GFRP were fabricated by hand lay up method and evaluated for their impact performance by conducting drop weight tests under low velocity impacts. The impact energy required for initiating a crack in the outer aluminium layer as well as the energy required for perforation was recorded. The impact load-time history was also recorded to understand the failure behavior. The damage depth and the damage area were measured to evaluate the impact resistance. Optical photography and scanning electron micrographs were taken to visualize the crack and the damage zone. The bidirectional cross-ply hybrid laminate (CPHL has been found to exhibit better impact performance and damage resistance than the unidirectional hybrid laminate (UDHL. Increase in aluminium thickness fraction (Al tf and fiber volume fraction (Vf resulted in an increase in the impact energy required for cracking and perforation. On an overall basis, the sandwich panels exhibited better impact performance than the monolithic aluminium.

  5. Deflection by kinetic impact: Sensitivity to asteroid properties

    Science.gov (United States)

    Bruck Syal, Megan; Michael Owen, J.; Miller, Paul L.

    2016-05-01

    Impacting an asteroid with a spacecraft traveling at high speed delivers an impulsive change in velocity to the body. In certain circumstances, this strategy could be used to deflect a hazardous asteroid, moving its orbital path off of an Earth-impacting course. However, the efficacy of momentum delivery to asteroids by hypervelocity impact is sensitive to both the impact conditions (particularly velocity) and specific characteristics of the target asteroid. Here we numerically model asteroid response to kinetic impactors under a wide range of initial conditions, using an Adaptive Smoothed Particle Hydrodynamics code. Impact velocities spanning 1-30 km/s were investigated, yielding, for a particular set of assumptions about the modeled target material, a power-law dependence consistent with a velocity-scaling exponent of μ = 0.44. Target characteristics including equation of state, strength model, porosity, rotational state, and shape were varied, and corresponding changes in asteroid response were documented. The kinetic-impact momentum-multiplication factor, β, decreases with increasing asteroid cohesion and increasing porosity. Although increased porosity lowers β, larger porosities result in greater deflection velocities, as a consequence of reduced target masses for asteroids of fixed size. Porosity also lowers disruption risk for kinetic impacts near the threshold of disruption. Including fast (P = 2.5 h) and very fast (P = 100 s) rotation did not significantly alter β but did affect the risk of disruption by the impact event. Asteroid shape is found to influence the efficiency of momentum delivery, as local slope conditions can change the orientation of the crater ejecta momentum vector. These results emphasize the need for asteroid characterization studies to bracket the range of target conditions expected at near-Earth asteroids while also highlighting some of the principal uncertainties associated with the kinetic-impact deflection strategy.

  6. The Impact of Wind Power Projects on Residential Property Values in the United States: A Multi-Site Hedonic Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hoen, Ben [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wiser, Ryan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Cappers, Peter [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Thayer, Mark [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sethi, Gautam [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2009-12-01

    This report uses statistical analysis to evaluate the impact of wind power projects on property values, and fails to uncovers conclusive evidence of the existence of any widespread property value impacts.

  7. Impact and dynamic mechanical thermal properties of textile silk reinforced epoxy resin composites

    Science.gov (United States)

    Yang, K.; Guan, J.

    2016-07-01

    Silk fabric reinforced epoxy resin composites (SFRPs) were prepared using simple techniques of hand lay-up, hot-press and vacuum treatment, and a series of volume fractions of silk reinforcements were achieved. The impact properties and dynamic mechanical properties of SFRPs were investigated using a pendulum impact testing method and dynamic mechanical thermal analysis (DMTA). The results suggest that silk reinforcement could greatly enhance the mechanical performances of SFRPs. The impact strength reached a maximum of 71 kJ/m2 for 60%-silk SFRP, which demonstrated a potential of silk composites for defence and impact- resistant materials.

  8. Drop Impact on Textile Material: Effect of Fabric Properties

    Directory of Open Access Journals (Sweden)

    Romdhani Zouhaier

    2014-09-01

    Full Text Available This paper presents an experimental study of impact of water drop on a surface in a spreading regime with no splashing. Three surfaces were studied: virgin glass, coating film and woven cotton fabric at different construction parameters. All experiments were carried out using water drop with the same free fall high. Digidrop with high-resolution camera is used to measure the different parameters characterising this phenomenon. Results show an important effect of the height of the free fall on the drop profile and the spreading behaviour. An important drop deformation at the surface impact was observed. Then, fabric construction as the weft count deeply affects the drop impact. For plain weave, an increase of weft count causes a decrease in penetration and increase in the spreading rate. The same result was obtained for coated fabric. Therefore, the impact energy was modified and the drop shape was affected, which directly influenced the spreading rate.

  9. Thermoplastic impact property improvement in hybrid natural fibre epoxy composite bumper beam

    Science.gov (United States)

    Davoodi, M. M.; Sapuan, S. M.; Ali, Aidy; Ahmad, D.; Khalina, A.

    2010-05-01

    Utilization of thermoset resin as a bumper beam composite matrix is currently more dominated in car manufacturer suppliers, because of availability, easy processing, low material cost and production equipment investment. Moreover, low viscosity, shrinkage and excellent flow facilitate better fibre impregnation and proper surface resin wetting. Three-dimensional cross linking curing increase impact, creep and environmental stress cracking resistance properties. Low impact properties of natural fibre epoxy composite, are main issues in its employment for automotive structural components. Impact properties in epoxy composite bumper beam could be increased by modifying the resin, reinforcement and manufacturing process as well as geometry parameters such as cross section, thickness, added ribs and fixing method optimizations could strengthen impact resistance. There are two main methods, flexibilisation and toughening, as modifying the resin in order to improve the impact properties of epoxy composite, which form single phase or two-phase morphology to make modifier as epoxy or from separate phase to keep the thermo-mechanical properties. Liquid rubber, thermoplastic, core shell particle and rigid particle are different methods of toughening improvements. In this research, thermoplastic toughening has used to improve impact properties in hybrid natural fibre epoxy composite for automotive bumper beam and has achieved reasonable impact improvements.

  10. Thermoplastic impact property improvement in hybrid natural fibre epoxy composite bumper beam

    Energy Technology Data Exchange (ETDEWEB)

    Davoodi, M M; Sapuan, S M; Ali, Aidy [Department of Mechanical and Manufacturing Engineering, Universiti Putra Malaysia 43400 UPM Serdang, Selangor (Malaysia); Ahmad, D; Khalina, A, E-mail: makinejadm2@asme.org [Department of Biological and Agricultural Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia)

    2010-05-15

    Utilization of thermoset resin as a bumper beam composite matrix is currently more dominated in car manufacturer suppliers, because of availability, easy processing, low material cost and production equipment investment. Moreover, low viscosity, shrinkage and excellent flow facilitate better fibre impregnation and proper surface resin wetting. Three-dimensional cross linking curing increase impact, creep and environmental stress cracking resistance properties. Low impact properties of natural fibre epoxy composite, are main issues in its employment for automotive structural components. Impact properties in epoxy composite bumper beam could be increased by modifying the resin, reinforcement and manufacturing process as well as geometry parameters such as cross section, thickness, added ribs and fixing method optimizations could strengthen impact resistance. There are two main methods, flexibilisation and toughening, as modifying the resin in order to improve the impact properties of epoxy composite, which form single phase or two-phase morphology to make modifier as epoxy or from separate phase to keep the thermo-mechanical properties. Liquid rubber, thermoplastic, core shell particle and rigid particle are different methods of toughening improvements. In this research, thermoplastic toughening has used to improve impact properties in hybrid natural fibre epoxy composite for automotive bumper beam and has achieved reasonable impact improvements.

  11. Modeling of Impact Properties of Auxetic Materials: Phase 1

    Science.gov (United States)

    2013-08-01

    underlying metal substrate from impact damage will be determined, and compared to the effect of solid polymer coatings (containing no honeycomb shaped air...higher indentation resistance, higher fracture toughness and greater resistance to impact damage . These unique features of the auxetic materials make... Elastoplasticity of auxetic materials, Computational Material Science, in press. [24] Horrigan, E.J., Smith, C.W., Scarpa, F.L., Gaspar, N., Javadi, A.A

  12. Dynamic Mechanical Properties and Fracture Surface Morphologies of Core-Shell Rubber (CSR) Toughened Epoxy at Liquid Nitrogen (Ln2) Temperatures

    Science.gov (United States)

    Wang, J.; Magee, D.; Schneider, J. A.

    2009-01-01

    The dynamic mechanical properties and fracture surface morphologies were evaluated for a commercial epoxy resin toughened with two types of core-shell rubber (CSR) toughening agents (Kane Ace(Registered TradeMark) MX130 and MX960). The impact resistance (R) was evaluated by the resulting breaking energy measured in Charpy impact tests conducted on an instrumented drop tower. The resulting fracture surface morphologies were examined using Scanning Electron Microscopy (SEM). Fractographic observations of the CSR toughened epoxy tested at ambient temperature, showed a fracture as characterized by slender dendrite textures with large voids. The increasing number of dendrites and decreasing size of scale-like texture with more CSR particles corresponded with increased R. As the temperature decreased to Liquid Nitrogen (LN 2), the fracture surfaces showed a fracture characterized by a rough, torn texture containing many river markings and deep furrows.

  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. On the Possible Influence of Small Impact on Geoengineering Properties of Subsoil

    Science.gov (United States)

    Smaga, A.; Radaszewski, R.; Wierzbicki, J.

    2016-08-01

    The main aim of the study was to investigate the changes in geoengineering properties of non lithified deposits below the craters in comparison to genetically the similar types of sediments unaffected by impact.

  15. Comparison of petrophysical properties of impactites for four meteoritic impact structures

    Science.gov (United States)

    Popov, Y.; Mayr, S.; Romushkevich, R.; Burkhardt, H.; Wilhelm, H.

    2014-05-01

    We reanalyzed and compared unique data sets, which we obtained in the frame of combined petrophysical and geothermal investigations within scientific drilling projects on four impact structures: the Puchezh-Katunki impact structure (Vorotilovo borehole, Russia), the Ries impact structure (Noerdlingen-73 borehole, Germany), the Chicxulub impact structure (ICDP Yaxcopoil-1 borehole, Mexico), and the Chesapeake impact structure (ICDP-USGS-Eyreville borehole, USA). For a joined interpretation, we used the following previously published data: thermal properties, using the optical scanning technique, and porosities, both measured on densely sampled halfcores of the boreholes. For the two ICDP boreholes, we also used our previously published P-wave velocities measured on a subset of cores. We show that thermal conductivity, thermal anisotropy, porosity, and velocity can be correlated with shock metamorphism (target rocks of the Puchezh-Katunki and Ries impact structures), and confirm the absence of shock metamorphism in the samples taken from megablocks (Chicxulub and Chesapeake impact structure). The physical properties of the lithic impact breccias and suevites are influenced mainly by their impact-related porosity. Physical properties of lower porosity lithic impact breccias and suevites are also influenced by their chemical composition. These data allow for a distinction between different types of breccias due to differences concerning the texture and chemistry and the different amounts of melt and rock clasts.

  16. 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...

  17. 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.

  18. Impact localization for a composite plate using the spatial focusing properties of advanced signal processing techniques

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hyunjo; Cho, Sungjong [Wonkwang Univ., Iksan (Korea, Republic of)

    2012-12-15

    A structural health monitoring technique for locating impact position in a composite plate is presented in this paper. The method employs a single sensor and spatial focusing properties of time reversal(TR) and inverse filtering(IF). We first examine the spatial focusing efficiency of both approaches at the impact position and its surroundings through impact experiments. The imaging results of impact localization show that the impact location can be accurately estimated in any position of the plate. Compared to existing techniques for locating impact or acoustic emission source, the proposed method has the benefits of using a single sensor and not requiring knowledge of anisotropic material properties and geometry of structures. Furthermore, it does not depend on a particular mode of dispersive Lamb waves that is frequently used in other ultrasonic testing of plate like structures.

  19. Effect of thermal aging on SCC and mechanical properties of stainless steel weld metals

    Energy Technology Data Exchange (ETDEWEB)

    Hixon, J.R. [U.S. Nuclear Regulatory Commission (United States); Kim, J.H.; Ballinger, R.G. [Massachusetts Inst. of Technology (United States)

    2007-07-01

    The thermal aging and consequent embrittlement of materials are ongoing issues in cast stainless steels and duplex stainless steel. Spinodal decomposition is largely responsible for the well known '475{sup o}C embrittlement that results in drastic reductions in ductility and toughness in these materials, and this process is operative in welds in either cast or wrought stainless steels where delta ferrite is present. While the embrittlement can occur after several hundred hours of aging at 475{sup o}C, the process is also operative at lower temperatures, including the 300{sup o}C operating temperature of a boiling water reactor (BWR), where ductility reductions have been observed after several tens of thousands of hours. An experimental program is under way in to understand how the spinodal decomposition may affect material properties changes in BWR pipe weld metals. Testing includes nano and micro-structural analysis as well as fatigue and SCC crack growth. In this study we report on the initial results of this program, including tensile, Charpy impact, fracture toughness and SCC crack growth rates of SS weld metals under simulated BWR conditions. The measurement of tensile, microhardness and Charpy-impact energy show an increase in strength, a decrease in ductility, and a decrease in impact energy after aging for 1000 hours at 430 and 400 {sup o}C. Crack growth rates for material in the as welded and aged for 5000 hours at 400{sup o}C have been measured and are generally within the scatter band for wrought material although the aged material data fall at the high end. Unusual insitu unstable fracture behavior has been experienced at toughness values significantly below (<50%) the room temperature fracture toughness. This behavior, termed 'environmental fracture' requires further investigation. (author)

  20. 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.

  1. Online Data Resources in Chemical Engineering Education: Impact of the Uncertainty Concept for Thermophysical Properties

    Science.gov (United States)

    Kim, Sun Hyung; Kang, Jeong Won; Kroenlein, Kenneth; Magee, Joseph W.; Diky, Vladimir; Muzny, Chris D.; Kazakov, Andrei F.; Chirico, Robert D.; Frenkel, Michael

    2013-01-01

    We review the concept of uncertainty for thermophysical properties and its critical impact for engineering applications in the core courses of chemical engineering education. To facilitate the translation of developments to engineering education, we employ NIST Web Thermo Tables to furnish properties data with their associated expanded…

  2. Impact of neutrino properties on the estimation of inflationary parameters from current and future observations

    CERN Document Server

    Gerbino, Martina; Vagnozzi, Sunny; Lattanzi, Massimiliano; Mena, Olga; Giusarma, Elena; Ho, Shirley

    2016-01-01

    We study the impact of assumptions about neutrino properties on the estimation of inflationary parameters from cosmological data, with a specific focus on the allowed contours in the $n_s/r$ plane. We study the following neutrino properties: (i) the total neutrino mass $ M_\

  3. Impact properties of 500-kg heat of V-4Cr-4Ti

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.M.; Nowicki, L.; Gazda, J. [Argonne National Lab., Chicago, IL (United States)] [and others

    1995-04-01

    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 industrial-scale (500-kg) heat of the alloy was fabricated successfully. The objective of this work is to determine the impact properties of the industrial-scale heat.

  4. Tethered polymer chains : surface chemistry and their impact on colloidal and surface properties

    NARCIS (Netherlands)

    Currie, EPK; Norde, W; Stuart, Martien A. Cohen

    2003-01-01

    In this review the grafting of polymer chains to solid supports or interfaces and the subsequent impact on colloidal properties is examined. We start by examining theoretical models for densely grafted polymers (brushes), experimental techniques for their preparation and the properties of the ensuin

  5. Tethered polymer chains: surface chemistry and their impact on colloidal and surface properties

    NARCIS (Netherlands)

    Currie, E.P.K.; Norde, W.; Cohen Stuart, M.A.

    2003-01-01

    In this review the grafting of polymer chains to solid supports or interfaces and the subsequent impact on colloidal properties is examined. We start by examining theoretical models for densely grafted polymers (brushes), experimental techniques for their preparation and the properties of the ensuin

  6. IMPACT OF OIL ON THE MECHANICAL PROPERTIES OF SOIL SUBSIDENCE

    Directory of Open Access Journals (Sweden)

    Алексей Алексеевич Бурцев

    2016-08-01

    Full Text Available The paper studied the effect of oil content on the mechanical properties of soil subsidence - Ek modulus and compressibility factor m0, obtained in the laboratory with the help of artificial impregnation oil soil samples. A comparison of the above parameters with samples of the same soil in the natural and water-saturated conditions has been perfomed.

  7. Knitted Strain Sensors: Impact of Design Parameters on Sensing Properties

    Directory of Open Access Journals (Sweden)

    Ozgur Atalay

    2014-03-01

    Full Text Available This paper presents a study of the sensing properties exhibited by textile-based knitted strain sensors. Knitted sensors were manufactured using flat-bed knitting technology, and electro-mechanical tests were subsequently performed on the specimens using a tensile testing machine to apply strain whilst the sensor was incorporated into a Wheatstone bridge arrangement to allow electrical monitoring. The sensing fabrics were manufactured from silver-plated nylon and elastomeric yarns. The component yarns offered similar diameters, bending characteristics and surface friction, but their production parameters differed in respect of the required yarn input tension, the number of conductive courses in the sensing structure and the elastomeric yarn extension characteristics. Experimental results showed that these manufacturing controls significantly affected the sensing properties of the knitted structures such that the gauge factor values, the working range and the linearity of the sensors varied according to the knitted structure. These results confirm that production parameters play a fundamental role in determining the physical behavior and the sensing properties of knitted sensors. It is thus possible to manipulate the sensing properties of knitted sensors and the sensor response may be engineered by varying the production parameters applied to specific designs.

  8. Drop Impact on Textile Material: Effect of Fabric Properties

    OpenAIRE

    2014-01-01

    This paper presents an experimental study of impact of water drop on a surface in a spreading regime with no splashing. Three surfaces were studied: virgin glass, coating film and woven cotton fabric at different construction parameters. All experiments were carried out using water drop with the same free fall high. Digidrop with high-resolution camera is used to measure the different parameters characterising this phenomenon. Results show an important effect of the height of the free fall on...

  9. Excellent Ballistic Impact Properties Demonstrated By New Fabric

    Science.gov (United States)

    Pereira, J. Michael; Revilock, Duane M.; Hopkins, Dale A.

    2002-01-01

    Recently, a relatively new industrial fiber known by the trade name Zylon has been under commercial development by Toyobo Co., Ltd., Japan. In ballistic impact tests conducted at the NASA Glenn Research Center, it was found that dry fabric braided of Zylon had greater ballistic impact capacity than comparable (braid style and weight) fabric braided of Kevlar. To study the potential use of Zylon fabric in jet engine containment systems, the fabric was tested in Glenn's Structures and Acoustics Division Ballistic Impact Facility under conditions simulating those which occur in a jet engine blade-out event. Circular ring test specimens were fabricated by wrapping five layers of braided Zylon or Kevlar fabric around an inner ring made of a thin sheet of aluminum and a 1-in.-thick layer of aluminum honeycomb. The test specimens had an inner diameter of 40 in., an axial length of 10 in., and a wall thickness of approximately 1.5in. A test specimen is shown in the photograph.

  10. Correlation of mechanical properties with metallurgical structure for 18Ni 200 grade maraging steel at room and cryogenic temperatures

    Science.gov (United States)

    Wagner, J. A.

    1991-01-01

    An extensive metallurgical study is presented which is intended to explain variations in the mechanical properties of Ni18 200 grade maraging steel in various product forms and orientations. Fracture toughness and Charpy impact values are found to decrease with decreasing temperature and be dependent on product form, specimen orientation, and metallurgical condition. Fatigue crack growth rates are dependent on temperature only. Fractographic analysis reveals that the decrease in toughness at -170 C is not associated with cleavage-type fracture morphology. Those specimens exhibiting low fracture toughness at room temperature or -170 C are found to have a significantly larger number of titanium-rich particles associated with dimple formation on the fracture surface.

  11. Effect of processing conditions on the mechanical and thermal properties of high-impact polypropylene nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Furlan, L.G. [Federal Institute of Rio Grande do Sul, IFRS, Campus Restinga, Estrada Joao Antonio da Silveira, 351, Porto Alegre 91790-400 (Brazil); Ferreira, C.I.; Dal Castel, C.; Santos, K.S.; Mello, A.C.E. [Chemistry Institute, Federal University of Rio Grande do Sul, UFRGS, Av. Bento Goncalves, 9500, Porto Alegre 91501-970 (Brazil); Liberman, S.A.; Oviedo, M.A.S. [Braskem S.A., III Polo Petroquimico, Via Oeste, Lote 5, Triunfo 95853-000 (Brazil); Mauler, R.S., E-mail: mauler@iq.ufrgs.br [Chemistry Institute, Federal University of Rio Grande do Sul, UFRGS, Av. Bento Goncalves, 9500, Porto Alegre 91501-970 (Brazil)

    2011-08-25

    Highlights: {yields} Polypropylene montmorillonite (PP-MMT) produced at different processing conditions. {yields} Polypropylene Nanocomposites with higher increase on impact resistance. {yields} Higher enhancement on mechanical properties. - Abstract: Polypropylene montmorillonite (PP-MMT) nanocomposites have been prepared by using a co-rotating twin screw extruder. The effects of processing conditions at fixed clay content (5 wt%) on polymer properties were investigated by means of transmission electron microscopy (TEM), flexural modulus, izod impact, dynamic mechanical analysis (DMA), and differential scanning calorimetry (DSC). It was noticed that the morphology and the mechanical properties of polypropylene nanocomposites were affected by different screw shear configuration. The results showed that the higher enhancement on mechanical properties was obtained by medium shear intensity profile instead of high configuration. An exceptional increase (maximum of 282%) on impact resistance was observed.

  12. Nanosilver: Properties, Applications and Impacts on Health and Environment

    Directory of Open Access Journals (Sweden)

    Patricia F. M. Nogueira

    2013-11-01

    Full Text Available Nanotechnology has developed rapidly in the last decade as a multidisciplinary field, with a myriad of applications in strategic areas including energy, electronics, medi-cine, biotechnology, among others. In modern days, the high commercial demand of silver nanoparticles (NPAg, in particular, has motivated a broad debate in the scientific community. This review gives a brief survey of the applications, commercialization and possible impacts of NPAg to human health and environment, with focus on their toxicity, transformation, and bioavailability. We also present a description of the current international laws and regulations regarding commercialization of nanomaterials.

  13. The Impact of Name Ambiguity on Properties of Coauthorship Networks

    Directory of Open Access Journals (Sweden)

    Kim, Jinseok

    2014-06-01

    Full Text Available Initial based disambiguation of author names is a common data pre-processing step in bibliometrics. It is widely accepted that this procedure can introduce errors into network data and any subsequent analytical results. What is not sufficiently understood is the precise impact of this step on the data and findings. We present an empirical answer to this question by comparing the impact of two commonly used initial based disambiguation methods against a reasonable proxy for ground truth data. We use DBLP, a database covering major journals and conferences in computer science and information science, as a source. We find that initial based disambiguation induces strong distortions in network metrics on the graph and node level: Authors become embedded in ties for which there is no empirical support, thus increasing their sphere of influence and diversity of involvement. Consequently, networks generated with initial-based disambiguation are more coherent and interconnected than the actual underlying networks, and individual authors appear to be more productive and more strongly embedded than they actually are.

  14. Impact properties of vanadium-base alloys irradiated at < 430 C

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-03-01

    Recent attention to vanadium-base alloys has focused on the effect of low-temperature (<430 C) neutron irradiation on the mechanical properties, especially the phenomena of loss of work-hardening capability under tensile loading and loss of dynamic toughness manifested by low impact energy and high ductile-brittle-transition temperature (DBTT). This paper summarizes results of an investigation of the low-temperature impact properties of V-5Ti, V-4Cr-4Ti, and V-3Ti-Si that were irradiated in several fission reactor experiments, i.e., FFTF-MOTA, EBR-II X-530, and ATR-A1. Irradiation performance of one production-scale and one laboratory heat of V-4C-4Ti and one laboratory heat of V-3Ti-Si was the focus of the investigation. Even among the same lass of alloy, strong heat-to-heat variation was observed in low-temperature impact properties. A laboratory heat of V-4Cr-4Ti and V-3Ti-1Si exhibited good impact properties whereas a 500-kg heat of V-4Cr-4Ti exhibited unacceptably high DBTT. The strong heat-to-heat variation in impact properties of V-4Cr-4Ti indicates that fabrication procedures and minor impurities play important roles in the low-temperature irradiation performance of the alloys.

  15. Mechanical properties of transgenic silkworm silk at high rate impact

    Science.gov (United States)

    Chu, Jou-Mei

    Transgenic silkworm silk was created to obtain the quality of spider silk while being mass-producible. Due to the variability in sequencing between the silkworm and spider DNA, the resulting transgenic silkworm silk may have different properties compared to spider silk. Furthermore, the high strain rate mechanical response of this new natural fiber is still unknown and needs to be characterized. In this experimental research, a quasi-static load frame (MTS) and a Kolsky tension bar are used to characterize the tensile stress-strain response of transgenic silkworm silk over a range of strain-rates between 10-3/s to 103/s. The results show that transgenic silkworm silk tends to have high overall elongation and initial stiffness at high strain rates compared to those of spider silk. Furthermore, specimen gage length sensitivity is studied with gage lengths of 3.97 mm (5/32 in), 4.76 mm (3/16 in), and 6.35 mm (1/4 in). Fracture surfaces are examined via Scanning Electron Microscopy (SEM) and reveal that the fracture mode is similar to that of spider silk. Therefore, it may be possible for the tensile properties of transgenic silkworm silk be comparable to that of spider silk.

  16. Microstructural evolution and mechanical properties of Inconel 718 after thermal exposure

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Z.S., E-mail: yuzaisong@tpri.com.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, No. 28, Xianning West Road, Xi’an 710049 (China); Xi' an Thermal Power Research Institute Co. Ltd., No. 136, Xingqing Road, Xi’an 710032 (China); Zhang, J.X. [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, No. 28, Xianning West Road, Xi’an 710049 (China); Yuan, Y.; Zhou, R.C.; Zhang, H.J.; Wang, H.Z. [Xi' an Thermal Power Research Institute Co. Ltd., No. 136, Xingqing Road, Xi’an 710032 (China)

    2015-05-14

    Inconel 718 was subjected to various heat treatments, i.e., solution heat treatment, standard ageing treatment and standard ageing plus 700 °C thermal exposure. The mechanical properties of the alloys were determined using tensile tests and Charpy pendulum impact tests at 650 °C and room temperature, respectively. The highest yield strength of 988 MPa was attained in the standard aged specimen, whereas a maximum impact toughness of 217 J cm{sup −2} was attained in the solution-treated specimen. After thermal exposure, the mechanical properties of the specimens degrade. Both the yield strength and impact toughness decreased monotonically with increasing thermal exposure time. Subjected to a 10000-h long-term thermal exposure, the yield strength dramatically decreased to 475 MPa (almost 50% of the maximum strength), and the impact toughness reduced to only 18 J cm{sup −2}. The microstructures of the specimens were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Coarsening of γ′ and γ″ and the transformation of γ″ to δ-Ni{sub 3}Nb was observed after thermal exposure. However, a complete transformation from metastable γ″ to δ-Ni{sub 3}Nb was never accomplished, even after the 10000-h long-term thermal exposure. Based on the obtained experimental results, the effects of the microstructural evolution on the mechanical properties are discussed.

  17. 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...

  18. Aerosol physical properties and their impact on climate change processes

    Science.gov (United States)

    Strzalkowska, Agata; Zielinski, Tymon; Petelski, Tomasz; Makuch, Przemyslaw; Pakszys, Paulina; Markuszewski, Piotr; Piskozub, Jacek; Drozdowska, Violetta; Gutowska, Dorota; Rozwadowska, Anna

    2013-04-01

    Characterizing aerosols involves the specification of not only their spatial and temporal distributions but their multi-component composition, particle size distribution and physical properties as well. Due to their light attenuation and scattering properties, aerosols influence radiance measured by satellite for ocean color remote sensing. Studies of marine aerosol production and transport are important for many earth sciences such as cloud physics, atmospheric optics, environmental pollution studies, and interaction between ocean and atmosphere. It was one of the reasons for the growth in the number of research programs dealing with marine aerosols. Sea salt aerosols are among the most abundant components of the atmospheric aerosol, and thus it exerts a strong influence on radiation, cloud formation, meteorology and chemistry of the marine atmosphere. An accurate understanding and description of these mechanisms is crucial to modeling climate and climate change. This work provides information on combined aerosol studies made with lidars and sun photometers onboard the ship and in different coastal areas. We concentrate on aerosol optical thickness and its variations with aerosol advections into the study area. We pay special attention to the problem of proper data collection and analyses techniques. We showed that in order to detect the dynamics of potential aerosol composition changes it is necessary to use data from different stations where measurements are made using the same techniques. The combination of such information with air mass back-trajectories and data collected at stations located on the route of air masses provides comprehensive picture of aerosol variations in the study area both vertically and horizontally. Acknowledgements: The support for this study was provided by the project Satellite Monitoring of the Baltic Sea Environment - SatBałtyk founded by European Union through European Regional Development Fund contract No. POIG 01

  19. The Effects of the Substitution of Wood Fiberwith Agro-based Fiber (Barley Straw on the Properties of Natural Fiber/Polypropylene Composites

    Directory of Open Access Journals (Sweden)

    Hyvärinen Marko

    2015-01-01

    Full Text Available Ecological concerns and the impending depletion of fossil fuels are driving the development of new bio-based, green products. Natural fibers are used increasingly as a filler or reinforcement in commercial thermoplastics due to their low cost, high specific properties and renewable nature. Agricultural byproducts and wastes are excellent alternative materials to supplement or substitute wood material as a reinforcement in composites.This comparative study focuses on the effects of the substitution of wood fiber with agro-basedfiber (barley straw on the mechanical and physical properties of natural fiber/polypropylene composites. The studied mechanical properties are flexural strength and modulus, Brinell hardness and Charpy impact strength. Water absorption and thickness swelling are studied as physical properties. Generally, the research resultsindicate that almost all the studied properties weakened significantlyas woodwas substituted with barley straw.Ofmechanical properties, the major decrease wasobserved in hardness.However, the use of barley straw slightlyimproved impact strength.The moisture-related properties, water absorption and thickness swelling,which have a great impact on the durability of a composite material, weakened significantly.

  20. Effect of Autogenous Arc Welding Processes on Tensile and Impact Properties of Ferritic Stainless Steel Joints

    Institute of Scientific and Technical Information of China (English)

    A K Lakshminarayanan; K Shanmugam; V Balasubramanian

    2009-01-01

    The effect of autogeneous arc welding processes on tensile and impact properties of ferritic stainless steel conformed to AISI 409M grade is studied.Rolled plates of 4 mm thickness have been used as the base material for preparing single pass butt welded jointa.Tensile and impact properties,microhardness,microstructure,and fracture surface morphology of continuous current gas tungsten arc welding (CCGTAW),pulsed current gas tungsten arc welding (PCGTAW),and plasma arc welding (PAW) joints are evaluated and the results are compared.It is found that the PAW joints of ferritic stainless steel show superior tensile and impact properties when compared with CCGTAW and PCGTAW joints,and this is mainly due to lower heat input,finer fusion zone grain diameter,and higher fusion zone hardness.

  1. The impact of surface properties on particle-interface interactions

    Science.gov (United States)

    Wang, Anna; Kaz, David; McGorty, Ryan; Manoharan, Vinothan N.

    2013-03-01

    The propensity for particles to bind to oil-water interfaces was first noted by Ramsden and Pickering over a century ago, and has been attributed to the huge reduction in surface energy when a particle breaches an oil-water interface and straddles it at its equilibrium height. Since then materials on a variety of length scales have been fabricated using particles at interfaces, from Pickering emulsions to Janus particles. In these applications, it is simply assumed that the particle sits at its hugely energetically favourable equilibrium position. However, it was recently shown that the relaxation of particles towards their equilibrium position is logarithmic in time and could take months, much longer than typical experiments. Here we investigate how surface charge and particle 'hairiness' impact the interaction between micron-sized particles and oil-water interfaces, and explore a molecular kinetic theory model to help understand these results. We use digital holographic microscopy to track micron-sized particles as they approach an oil-water interface with a resolution of 2 nm in all three dimensions at up to thousands of frames per second.

  2. Extent of pyrolysis impacts on fast pyrolysis biochar properties.

    Science.gov (United States)

    Brewer, Catherine E; Hu, Yan-Yan; Schmidt-Rohr, Klaus; Loynachan, Thomas E; Laird, David A; Brown, Robert C

    2012-01-01

    A potential concern about the use of fast pyrolysis rather than slow pyrolysis biochars as soil amendments is that they may contain high levels of bioavailable C due to short particle residence times in the reactors, which could reduce the stability of biochar C and cause nutrient immobilization in soils. To investigate this concern, three corn ( L.) stover fast pyrolysis biochars prepared using different reactor conditions were chemically and physically characterized to determine their extent of pyrolysis. These biochars were also incubated in soil to assess their impact on soil CO emissions, nutrient availability, microorganism population growth, and water retention capacity. Elemental analysis and quantitative solid-state C nuclear magnetic resonance spectroscopy showed variation in O functional groups (associated primarily with carbohydrates) and aromatic C, which could be used to define extent of pyrolysis. A 24-wk incubation performed using a sandy soil amended with 0.5 wt% of corn stover biochar showed a small but significant decrease in soil CO emissions and a decrease in the bacteria:fungi ratios with extent of pyrolysis. Relative to the control soil, biochar-amended soils had small increases in CO emissions and extractable nutrients, but similar microorganism populations, extractable NO levels, and water retention capacities. Corn stover amendments, by contrast, significantly increased soil CO emissions and microbial populations, and reduced extractable NO. These results indicate that C in fast pyrolysis biochar is stable in soil environments and will not appreciably contribute to nutrient immobilization.

  3. Impact Properties of Copper-Alloyed and Nickel-Copper Alloyed ADI

    Science.gov (United States)

    Batra, Uma; Ray, Subrata; Prabhakar, S. R.

    2007-08-01

    The influence of austenitization and austempering parameters on the impact properties of copper-alloyed and nickel-copper-alloyed austempered ductile irons (ADIs) has been studied. The austenitization temperature of 850 and 900 °C have been used in the present study for which austempering time periods of 120 and 60 min were optimized in an earlier work. The austempering process was carried out for 60 min for three austempering temperatures of 270, 330, and 380 °C to study the effect of austempering temperature. The influence of the austempering time on impact properties has been studied for austempering temperature of 330 °C for time periods of 30-150 min. The variation in impact strength with the austenitization and austempering parameters has been correlated to the morphology, size and amount of austenite and bainitic ferrite in the austempered structure. The fracture surface of ADI failed under impact has been studied using SEM.

  4. Aviation Impacts on Property Values and Management: The Case of Suvarnabhumi International Airport

    Directory of Open Access Journals (Sweden)

    Patcharin Limlomwongse Suksmith

    2015-07-01

    Full Text Available Many countries have developed policies and measures to deal with the external impact of aviation on the wider community. There is, however, often controversy and lack of acceptance of some measures, such as compensation, in the communities affected by aviation. Such measures are often felt to be ineffective and perceived as unfair. A clear and objective model for determining compensation would be helpful to reduce controversy. The objective of this study is therefore to examine the relationship between aviation impacts and property values in the case of Thailand's Suvarnabhumi Airport for application to the possible improvement of compensation packages. Multiple regression analysis was used to determine the relationship between five common impacts of aviation (safety, noise, scenery, air pollution, and traffic and property value change, with data from a survey of sample communities around the airport. The results, both for the overall neighborhood and for separate land used types, show that only noise and air pollution demonstrate significant negative relations with property value. The effect of noise drives a higher impact on property price than the effect of air pollution. The main contribution of this research is to improve developing country compensation models by applied measurement from regression analysis to identify factors with significant impacts, using property value change as proxy to measure the impact of the airport. For example, in the case of Thailand, a compensation model should consider noise and air pollution as the main factors rather than consider only noise contour area. The higher weight on noise should be designed to reflect land use types. Furthermore the market value of property loss should be taken into account when designing a compensation package. The survey and regression method used in this study can be adapted for finding relevant factors and suggesting appropriate compensation for other environmental and

  5. Impact of fuel properties on advanced power systems

    Energy Technology Data Exchange (ETDEWEB)

    Sondreal, E.A.; Jones, M.L.; Hurley, J.P.; Benson, S.A.; Willson, W.G. [Univ. of North Dakota, Grand Forks, ND (United States)

    1995-12-01

    Advanced coal-fired combined-cycle power systems currently in development and demonstration have the goal of increasing generating efficiency to a level approaching 50% while reducing the cost of electricity from new plants by 20% and meeting stringent standards on emissions of SO{sub x} NO{sub x} fine particulates, and air toxic metals. Achieving these benefits requires that clean hot gas be delivered to a gas turbine at a temperature approaching 1350{degrees}C, while minimizing energy losses in the gasification, combustion, heat transfer, and/or gas cleaning equipment used to generate the hot gas. Minimizing capital cost also requires that the different stages of the system be integrated as simply and compactly as possible. Second-generation technologies including integrated gasification combined cycle (IGCC), pressurized fluidized-bed combustion (PFBC), externally fired combined cycle (EFCC), and other advanced combustion systems rely on different high-temperature combinations of heat exchange, gas filtration, and sulfur capture to meet these requirements. This paper describes the various properties of lignite and brown coals.

  6. Impact of urban pollution emitted in Warsaw on aerosol properties

    Science.gov (United States)

    Zawadzka, O.; Markowicz, K. M.; Pietruczuk, A.; Zielinski, T.; Jaroslawski, J.

    2013-04-01

    This paper presents the analyses of the long-term observations of aerosol optical thickness (AOT) and concentrations of particulate matter with an aerodynamic diameter CIMEL (Belsk) sun photometers. The PM10 concentrations were measured at three Warsaw stations as well as in Belsk. The ground-based observations, and the satellite data from the Moderate Resolution Imaging Spectroradiometer (MODIS) provided information about the influence of Warsaw emissions on the AOT. The estimated effect is about 0.02 (at 500 nm) based on the sun photometers' comparisons and 0.03 (at 550 nm) based on the MODIS results. Relatively small impact of Warsaw emissions on the AOT (about 10-15%) is consistent with the PM10 data. The mean PM10 differences, estimated during the same time as sun photometer measurements, for Warsaw Ursynow (a residential area) and Belsk was only 5.7 μg m-3 (13%), and for Warsaw Targowek (a mixed shopping and residential area) and Belsk was about 9.8 μg m-3 (20%). For the station located in the central Warsaw, near to the street with the heavy traffic, the difference in the long-term mean of the PM10 was significantly larger and reached 22.1 μg m-3 (36%). Finally, an extreme smoke event observed on 4 April 2009, when favorable weather conditions led to the differences in the AOT between Warsaw and Belsk in a range of 0.11-0.2 (at 500 nm) has been described.

  7. Impact of coupling agent on properties of wood-plastic composite

    Institute of Scientific and Technical Information of China (English)

    XU Min; LI Shuai

    2007-01-01

    The impact ortwo couphng agents,maleic anhydride (coupling agent 1) and isocyanate (coupling agent 2) on the properties of wood-plastic composites (WPC) was studied.Wood-plastic composites were made with coupling agents 1 and 2 and properties were tested under the condition that the ratio of wood fiber to thermoplastic polymer was 7:3,target density was 0.7 g/cm3,press temperature was 175℃,press time was 8 min,and adding amount of coupling agent 2%.Results show that coupling agent 2 was superior to coupling agent 1 and had great effect on the physical and mechanical properties of WPC.When using the same coupling agent,the impact on their properties varied with different thermoplastic polymers.

  8. Flexural, Impact Properties and Sem Analysis of Bamboo and Glass Fiber Reinforced Polyester Hybrid Composites

    Directory of Open Access Journals (Sweden)

    Raghavendra Rao. H

    2014-08-01

    Full Text Available The Flexural, Impact properties and Scanning electron microscope analysis of Bamboo/glass fibers Reinforced polyester Hybrid composites were studied. The effect of alkali treatment of the bamboo fibers on these properties was also studied. It was observed that the Flexural, impact properties of the hybrid composite increase with glass fiber content. These properties found to be higher when alkali treated bamboo fibers were used in the hybrid composites. The elimination of amorphous hemi-cellulose with alkali treated leading to higher crystallinity of the bamboo fibers with alkali treatment may be responsible for these observations. The author investigated the interfacial bonding between Glass/Bamboo reinforced polyester composites. The effect of alkali treatment on the bonding between Glass/Bamboo composites was also studied.

  9. The New Cispadana Motorway. Impact on Industrial Buildings Property Values

    Directory of Open Access Journals (Sweden)

    Simona Tondelli

    2012-11-01

    Full Text Available Infrastructures, through externalities, modify the territorial status quo: by creating advantages and disadvantages, they lead to inequalities and territorial cohesion problems, calling for a setup of territorial equalization mechanisms. In this paper, the estimation of the costs and benefits generated from the building of the new Cispadana regional motorway (Emilia-Romagna Region, Italy is described. The study focuses on the price variations of the industrial buildings property values in the real estate market after the new motorway will be built, aiming at developing a forecasting method, which could be repeatable and applicable to other kinds of externalities. Thanks to the hedonic pricing method, which is recurring in transport literature, using a multiple linear regression model based on ordinary least squares method (OLS, the contribution of the accessibility on the industrial buildings' pricing has been isolated; it was then possible to forecast the rise in the industrial buildings prices that will be due to the accessibility variation produced by the new infrastructure. The purpose of such a procedure is the setup of equalization mechanisms, which can re-balance the territorial effects though he so-called “land value capture” tools. Thanks to a relatively quick phase of development and implementation, the  described application could be used as a tool for the ex-ante evaluation of different infrastructure projects and as an ex-post analysis tool for the monitoring of an existing infrastructure. Finally, thanks to the chance to understand the contribution of each territorial feature to the final price of the good, this application could be very useful in participatory planning processes because it could provide a common knowledge base which could be used to support the public administration’s capability of negotiation with the private partner, both in the  participatory planning processes and in the public-private partnership

  10. THE INVESTIGATION OF FRACTURE PROPERTIES OF SISAL TEXTILE REINFORCED POLYMERS

    Institute of Scientific and Technical Information of China (English)

    LiYan

    2004-01-01

    Sisal fibre is a kind of natural fibre which possesses high specific strength and modulus, low price, recycalability, easy availability in some countries. Using sisal fibre as reinforcement to make sisal fibre reinforced polymer composites has aroused great interest of materials scientists and engineers all over the world. Many researches have been done in recent years which include the study of mechanical properties of the composites, finding an efficient way to improve the interfacial bonding properties between sisal fibre and polymeric matrices and fibre surface treatment on the mechanical performance of the composites. Though many researches on sisal fibre reinforced composites have been done so far, none deals with the fracture properties of this novel composite which is crucial for the actual application of this material. In this research, Charpy impact test and compact tension test were employed to study the fracture toughness of sisal fibre reinforced vinyl ester and epoxy composites. The effect of fibre surface treatment on the fracture properties of these composites by permanganate and silane was evaluated. The initiation and propagation of the crack were observed with optical microscopy (OM). The fracture morphologies revealed by OM explains the fracture phenomenon of sisal fibre reinforced composites.

  11. The economic impacts of noxious facilities on wages and property values: An exploratory analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nieves, L.A.; Hemphill, R.C.; Clark, D.E.

    1991-05-01

    Recent assessments of socioeconomic impacts resulting from the location of potentially hazardous facilities have concentrated on the issue of negative public perceptions and their resulting economic consequences. This report presents an analysis designed to answer the question: Can economic impacts resulting from negative perceptions of ``noxious facilities`` be identified and measured? To identify the impacts of negative perceptions, data on noxious facilities sited throughout the United States were compiled, and secondary economic and demographic data sufficient to analyze the economic impacts on the surrounding study areas were assembled. This study uses wage rate and property value differentials to measure impacts on social welfare so that the extent to which noxious facilities and their associated activities have affected surrounding areas can be determined.

  12. The economic impacts of noxious facilities on wages and property values: An exploratory analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nieves, L.A.; Hemphill, R.C.; Clark, D.E.

    1991-05-01

    Recent assessments of socioeconomic impacts resulting from the location of potentially hazardous facilities have concentrated on the issue of negative public perceptions and their resulting economic consequences. This report presents an analysis designed to answer the question: Can economic impacts resulting from negative perceptions of noxious facilities'' be identified and measured To identify the impacts of negative perceptions, data on noxious facilities sited throughout the United States were compiled, and secondary economic and demographic data sufficient to analyze the economic impacts on the surrounding study areas were assembled. This study uses wage rate and property value differentials to measure impacts on social welfare so that the extent to which noxious facilities and their associated activities have affected surrounding areas can be determined.

  13. The impact of freeze-drying on microstructure and rehydration properties of carrot

    NARCIS (Netherlands)

    Voda, A.; Homan, N.; Witek, M.; Duijster, A.; Dalen, van G.; Sman, van der R.G.M.; Nijsse, J.; Vliet, van L.J.; As, van H.; Duynhoven, van J.P.M.

    2012-01-01

    The impact of freeze-drying, blanching and freezing rate pre-treatments on the microstructure and on the rehydration properties of winter carrots were studied by µCT, SEM, MRI and NMR techniques. The freezing rate determines the size of ice crystals being formed that leave pores upon drying. Their a

  14. Effect of ultrasonic impact treatment on the mechanical properties of titanium nickelide single crystal

    Science.gov (United States)

    Surikova, N. S.; Narkevich, N. A.; Surikov, N. Yu.; Vlasov, I. V.; Ovchinnikov, S. V.; Mironov, Yu. P.; Gritsenko, B. P.

    2016-10-01

    Optical and transmission electron microscopy, X-ray diffraction analysis, nanoindentation, measurements of wear, and mechanical uniaxial tensile tests have been used to study the effect of ultrasonic impact surface treatment on the fine structure and the mechanical properties of the surface layers and the deformation behavior of TiNi(Fe, Mo) bulk single crystal samples.

  15. The impact of ants on mineral soil properties and processes at different spatial scales

    NARCIS (Netherlands)

    Cammeraat, E.L.H.; Risch, A.C.

    2008-01-01

    Soil dwelling ants are important soil engineers that have a large impact on the soil ecosystem. This is reflected in the alteration of soil properties by ants due to burrowing activities, the accumulation of organic matter and other nutrients in the soil, which, in turn, alters soil physical, chemic

  16. Intellectual Property Rights in Plant Breeding and Biotechnology: assessing impact on the Indian seed industry

    NARCIS (Netherlands)

    Pal, S.; Tripp, R.; Louwaars, N.P.

    2007-01-01

    The enactment of Intellectual Property Rights legislation and its enforcement are two distinct tasks, and the latter requires development of institutional capacity. The impact of IPRs should be seen in conjunction with economic policies and other regulations like seed and biosafety rules, which are

  17. The impact of carbohydrate and protein level and sources on swine manure foaming properties

    Science.gov (United States)

    This study explored the impact of swine diet on the composition, methane production potential, and foaming properties of manure. Samples of swine manure were collected from controlled feeding trials with diets varying in protein and carbohydrate levels and sources. Protein sources consisted of corn ...

  18. Impact of dietary carbohydrate and protein source and content on swine manure foaming properties

    Science.gov (United States)

    Diet ingredients are thought to contribute to foaming problems associated with swine deep-pit systems. Two experiments explored the impact of protein and carbohydrate sources in swine diets on the physicochemical properties, methane production potential, and foaming characteristics of swine manure. ...

  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. Effect of laser beam position on mechanical properties of F82H/SUS316L butt-joint welded by fiber laser

    Energy Technology Data Exchange (ETDEWEB)

    Serizawa, Hisashi, E-mail: serizawa@jwri.osaka-u.ac.jp [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Mori, Daiki; Ogiwara, Hiroyuki; Mori, Hiroaki [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2014-10-15

    Highlights: • The micro hardness of weld metal in F82H/SUS316L joint partially decreases after PWHT by shifting beam position to SUS316L. • Charpy impact energy of F82H/SUS316L joint obviously increases after PWHT due to the release of residual stress. • The tensile strength of weld metal in F82H/SUS316L joint is higher than that of SUS316L. • The fiber laser welding seems to be one of the most candidate methods to join between F82H and SUS316L pipes practically. - Abstract: A dissimilar butt-joint between reduced activation ferritic/martensitic steel F82H and SUS316L austenitic stainless steel was made by 4 kW fiber laser and the influence of laser beam position on its mechanical properties before and after post-weld heat treatment (PWHT) was examined at room temperature. From the nano-indentation measurements and the microstructural observations, it is found that the micro hardness of weld metal partially decreases after PWHT by shifting beam position to SUS316L because its phase seems to move from only the martensitic phase to the mixture of austenitic and martensitic phases. In addition, Charpy impact test suggests that the impact energy slightly increases by shifting beam position before PWHT and obviously increases after PWHT due to the release of residual stress. Moreover, the tensile test indicates that the tensile strength of weld metal is higher than that of SUS316L and the fracture occurs at the base metal of SUS316L regardless of laser beam position.

  1. Tensile and Impact Properties of Shielded Metal Arc Welded AISI 409M Ferritic Stainless Steel Joints

    Institute of Scientific and Technical Information of China (English)

    K.Shanmugam; A.K.Lakshminarayanan; V.Balasubramanian

    2009-01-01

    The present study is concerned with the effect of filler metals such as austenitic stainless steel, ferritic stainless steel and duplex stainless steel on tensile and impact properties of the ferritic stainless steel conforming to AISI 409M grade. Rolled plates of 4 mm thickness were used as the base material for preparing single pass butt welded joints. Tensile and impact properties, microhardness, microstructure and fracture surface morphology of the joints fabricated by austenitic stainless steel, ferritic stainless steel and duplex stainless steel filler metals were evaluated and the results were reported. From this investigation, it is found that the joints fabricated by duplex stainless steel filler metal showed higher tensile strength and hardness compared to the joints fabricated by austenitic and ferritic stainless steel filler metals. Joints fabricated by austenitic stainless steel filler metal exhibited higher ductility and impact toughness compared with the joints fabricated by ferritic stainless steel and duplex stainless steel filler metals.

  2. The influence of high and low temperatures on the impact properties of glass–epoxy composites

    Directory of Open Access Journals (Sweden)

    SLAVISA PUTIC

    2007-07-01

    Full Text Available The aim of this paper is to present the influence of high and low temperatures on the impact properties glass–epoxy composites. The impact strength an is presented for four different glass–epoxy composite structures at three different temperatures, i.e., at room temperature t = 20 °C, at an elevated temperature t = +50 °C and at a low temperature t = –50 °C. Standard mechanical testing was carried out on the composite materials with specific masses of reinforcement of 210 g m-2 and 550 g m-2 and orientations 0°/90° and ±45°. Micromechanical analysis of the failure was performed in order to determine real models and mechanisms of crack and temperature influence on the impact properties.

  3. Impact of wheat bran derived arabinoxylanoligosaccharides and associated ferulic acid on dough and bread properties.

    Science.gov (United States)

    Snelders, Jeroen; Dornez, Emmie; Delcour, Jan A; Courtin, Christophe M

    2014-07-23

    The impact of arabinoxylanoligosaccharides (AXOS) with varying bound or free ferulic acid (FA) content on dough and bread properties was studied in view of their prebiotic and antioxidant properties. AXOS with an FA content of 0.1-1.7% caused an increase in dough firmness with increasing AXOS concentration. AXOS with a high FA content (7.2%), on the contrary, resulted in an increase in dough extensibility and a decrease in resistance to extension, similar to that for free FA, when added in levels up to 2%. Higher levels resulted in unmanageable dough. A limited impact on dough gluten network formation was observed. These results suggest that for highly feruloylated AXOS, the FA-mediated dough softening supersedes the firming effect displayed by the carbohydrate moiety of AXOS. The impact of the different AXOS on bread volume, however, was minimal. Furthermore, AXOS in bread were not engaged in covalent cross-linking and significantly increased its antioxidant capacity.

  4. Impact property enhancement of poly (lactic acid) with different flexible copolymers

    Science.gov (United States)

    Likittanaprasong, N.; Seadan, M.; Suttiruengwong, S.

    2015-07-01

    The objective of this work was to improve the impact property of Poly (lactic acid) (PLA) by blending with different copolymers. Six flexible copolymers, namely, acrylonitrile butadiene styrene (ABS) powder, Biomax, polybutyrate adipate co-terephthalate (PBAT), polyether block amide (PEBAX), ethylene-vinyl acetate (EVA) and ethylene acrylic elastomer (EAE), with loading less than 20wt% were used and compared. The rheological, mechanical and morphological properties of samples were investigated by melt flow index, tensile testing, impact testing and scanning electron microscope (SEM), respectively. It was found that PLA added 20wt% EAE showed the highest impact strength (59.5 kJ/m2), which was 22 times higher than neat PLA. The elongation at break was also increased by 12 folds compared to neat PLA. The SEM images showed good interface and distribution for PLA containing 20wt% EAE, 15 phr Biomax and 20 wt% PEBAX.

  5. Physical and Social Impacts on Hydrologic Properties of Residential Lawn Soils

    Science.gov (United States)

    Smith, M. L.; Band, L. E.

    2009-12-01

    Land development practices result in compacted soils that filter less water, increase surface runoff and decrease groundwater infiltration. Literature review of soil infiltration rates reveals that developed sites’ rates, 0.1 to 24 cm/hr, are reduced when compared to rates of undeveloped sites, 14.7 to 48.7 cm/hr. Yet, most hydrologic models neglect the impacts of residential soil compaction on infiltration and runoff. The objectives of this study included: determination of differences between soil properties of forested and residential lawn sites in Baltimore Ecosystem Study; parcel-scale location impacts on soil properties; and the impact of social and physical factors on the distribution of soil properties of residential lawns. Infiltration measures were collected in situ using a Cornell Sprinkle Infiltrometer and soil cores were collected for water retention and texture analysis. These soil properties were paired with GIS data relating to age of house construction, property value, parcel area, percent canopy cover per parcel and parcel distance from stream. The study finds that saturated infiltration rates in residential lawn soils are significantly lower than forest soils due to reduced macroporosity of residential lawn soils. Intra-parcel differences in bulk density and soil depth indicate that runoff from residential lawns is more likely from near-house and near-curb locations than the mid-front or backyards. The range of infiltration rate, bulk density and percent organic matter can be explained by readily attainable social and physical factors—age of house construction and parcel distance to stream. The impacts of land management on soil properties appear to be more prominent than percent canopy.

  6. Effects of impurity elements on mechanical properties and microstructures of reduced-activation ferritic/martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Sawahata, A. [Ibaraki Univ., Graduate School of Science and Engineering, Hitachi (Japan); Tanigawa, H.; Shiba, K. [Japan Atomic Energy Agency, Naga-gun, Ibaraki-ken (Japan); Enomoto, M. [Ibaraki Univ., Dept. of Materials Science, Faculty of Engineering, Hitachi (Japan)

    2007-07-01

    Full text of publication follows: Reduced activation ferritic/martensitic steels (RAFs), such as F82H (Fe-8Cr-2W-0.2V- 0.04Ta-0.1C, in wt%), are one of the leading candidates for structural materials of fusion reactors. Impact property of F82H can be improved by adjusting the amount of tantalum or titanium concentration. On the other hand, it was reported by microstructure analyses of IEA steel that tantalum has a tendency to form oxides and causes a large dispersion of fracture toughness. In this study, the correlation between titanium or tantalum concentration and the impact property were reported focusing on difference in microstructure. Charpy impact test and microstructure analyses were carried out against modified F82H series of which titanium, nitrogen and tantalum composition were controlled. Charpy impact test results showed that the ductile-brittle transition temperature (DBTT) of T05A (0.05Ta- 0.0014N-impact property. The influence of tantalum concentration on the formation of these oxides and mechanical properties will be reported. (authors)

  7. Impact of lux gene insertion on bacterial surface properties and transport.

    Science.gov (United States)

    Chen, Gang; Srinivasa Ranga, Vijay Penagonda; Mao, Yongjun; Chen, Kevin; Qiao, Hanzi

    2008-03-01

    Genetic markers have been in popular use for tracing microbial movement in the environment. However, the impact of genetic marker insertion on microbial surface properties and consequent transport is often ignored. For this research, we investigated the impact of luminescence-based genetic marker insertion on bacterial surface properties and transport. Typical Gram-positive bacterial strains of Lactobacillus casei, Streptococcus mitis and Micrococcus luteus were used as model bacterial strains in this research. We manipulated gene transfer to observe the impact of lux gene insertion on bacterial surface properties based on contact angle measurements, and we conducted column experiments to evaluate the impact of lux gene insertion on bacterial transport. After lux gene insertion, bacterial interactions with the porous media increased, demonstrating stronger deposition potential in the porous media. Accordingly, retention of the daughter strains increased. Lux gene insertion also resulted in an increase in bacterial dispersion and equilibrium adsorption in the porous media. The bacterial deposition coefficient was found to correlate with the free energy of interactions between bacteria and the porous media.

  8. The sensitivity of the burst performance of impact damaged pressure vessels to material strength properties

    Science.gov (United States)

    Lasn, K.; Vedvik, N. P.; Echtermeyer, A. T.

    2016-07-01

    This numerical study is carried out to improve the understanding of short-term residual strength of impacted composite pressure vessels. The relationship between the impact, created damage and residual strength is predicted by finite element (FE) analysis. The burst predictions depend largely on the strength properties used in the material models. However, it is typically not possible to measure all laminate properties on filament wound structures. Reasonable testing efforts are concentrated on critical properties, while obtaining other less sensitive parameters from e.g. literature. A parametric FE model is hereby employed to identify the critical strength properties, focusing on the cylindrical section of the pressure vessel. The model simulates an impactor strike on an empty vessel, which is subsequently pressurized until burst. Monte Carlo Simulations (MCS) are employed to investigate the correlations between strength related material parameters and the burst pressure. The simulations indicate the fracture toughness of the composite, hoop layer tensile strength and the yield stress of the PE liner as the most influential parameters for current vessel and impact configurations. In addition, the conservative variation in strength parameters is shown to have a rather moderate effect (COV ca. 7%) on residual burst pressures.

  9. Impact properties of rubber-modified epoxy resin-graphite-fiber composites

    Science.gov (United States)

    Gilwee, W. J.; Nir, Z.

    1984-01-01

    To improve the impact resistance of graphite-fiber composites, a commercial and an experimental epoxy resin were modified with liquid reactive rubber and a brominated epoxy resin. The commercial epoxy was a tetrafunctional resin, and the experimental epoxy was a trifunctional resin. The reactive rubber was a carboxyl-terminated butadiene-acrylonitrile copolymer. The rubber content was varied from 0 to 25 percent (wt). The brominated epoxy resin was used at Br levels of 4, 19, and 35 percent of the resin. Composites were prepared with woven graphite cloth reinforcement. The composites were evaluated by using flexural strength in the dry state and an elevated temperature after saturation with water. The impact properties were determined by measuring shear strength after falling-ball impact and instrumented impact. The rubber-modified, trifunctional resin exhibited better properties, when tested in hot-wet conditions in a heated oven at 366 K (after boiling the material for 2 h in demineralized water), than the tetrafunctional resin. Improved impact resistance was observed with the addition of the reactive rubber to the epoxy resin. Further improvement was observed with the addition of the brominated epoxy resin.

  10. Determination of mechanical properties of impacted human morsellized cancellous allografts for revision joint arthroplasty.

    Science.gov (United States)

    Tanabe, Y; Wakui, T; Kobayashi, A; Ohashi, H; Kadoya, Y; Yamano, Y

    1999-12-01

    This paper deals with the characterization of mechanical properties of impacted morsellized cancellous allograft (IMCA) produced by dynamic compaction of allograft femoral heads ground by commercially available bone mills, i.e. rotating rasp and reciprocating type bone mills. Various ranges and profiles of particle size in the graft aggregates were obtained using these bone mills, and the effect of number of compaction as well as the distribution of particle sizes on the mechanical properties of IMCA under quasistatic compression and shear loading conditions was discussed. The morsellized cancellous allograft prepared by the reciprocating type bone mill showed a broad distribution of particle sizes, and gave IMCA superior mechanical properties to the graft with a more uniform size distribution, or prepared by the rotating rasp type bone mills. The increase of number of compaction also improved the mechanical properties of IMCA in compression.

  11. Effect of nanoparticles on tensile, impact and fatigue properties of fibre reinforced plastics

    Indian Academy of Sciences (India)

    R Nagalingam; S Sundaram; B Stanly Jones Retnam

    2010-10-01

    Advanced composite, fibre-reinforced polymer (FRP), has been favoured for certain aerospace, military, marine and automotive applications. Polymer nanocomposites containing layered silicates have attracted much attention. These exhibit increased modulus, decreased thermal expansion coefficient, increased solvent resistance and enhanced ionic conductivity when compared to the polymer alone. Here we have developed eight different combinations of composites FRP with nanoclay (montmorillonite) by layered manufacturing techniques (LM) and measured the mechanical properties. The measurement showed that the tensile strength, impact strength and fatigue life are greatly increased. A plausible explanation for high increase of properties has also been discussed.

  12. Effects of Alloying Elements on the Microstructures and Mechanical Properties of Heavy Section Ductile Cast Iron

    Institute of Scientific and Technical Information of China (English)

    G.S. Cho; K.H. Choe; K.W. Lee; A.Ikenaga

    2007-01-01

    The effects of alloying elements on the as-cast microstructures and mechanical properties of heavy section ductile cast iron were investigated to develop press die material having high strength and high ductility.Measurements of ultimate tensile strength, 0.2% proof strength, elongation and unnotched Charpy impact energy are presented as a function of alloy amounts within 0.25 to 0.75 wt pct range. Hardness is measured on the broken tensile specimens. The small additions of Mo, Cu, Ni and Cr changed the as-cast mechanical properties owing to the different as-cast matrix microstructures. The ferrite matrix of Mo and Ni alloyed cast iron exhibits Iow strength and hardness as well as high elongation and impact energy. The increase in Mo and Ni contents developed some fractions of pearlite structures near the austenite eutectic cell boundaries, which caused the elongation and impact energy to drop in a small range. Adding Cu and Cr elements rapidly changed the ferrite matrix into pearlite matrix, so strength and hardness were significantly increased. As more Mo and Cr were added. the size and fraction of primary carbides in the eutectic cell boundaries increased through the segregation of these elements into the intercellular boundaries.

  13. Material properties of the F82H melted in an electric arc furnace

    Energy Technology Data Exchange (ETDEWEB)

    Sakasegawa, Hideo, E-mail: sakasegawa.hideo@jaea.go.jp [Japan Atomic Energy Agency, Rokkasho, Aomori (Japan); Tanigawa, Hiroyasu [Japan Atomic Energy Agency, Rokkasho, Aomori (Japan); Kano, Sho; Abe, Hiroaki [Institute for Materials Research, Tohoku university, Sendai, Miyagi (Japan)

    2015-10-15

    Highlights: • We studied material properties of reduced activation ferritic/martensitic steel. • We melted F82H using a 20 tons electric arc furnace for the first time. • Mass effect likely affected material properties. • MX (M: Metal, C: Carbon and/or Nitrogen) precipitates mainly formed on grain and sub grain boundaries. - Abstract: Fusion DEMO reactor requires over 11,000 tons of reduced activation ferritic/martensitic steel. It is necessary to develop the manufacturing technology for fabricating such large-scale steel with appropriate mechanical properties. In this work, we focused fundamental mechanical properties and microstructures of F82H-BA12 heat which was melted using a 20 tons electric arc furnace followed by electroslag remelting process. Its raw material of iron was blast furnace iron, because the production volume of electrolytic iron which has been used in former heats, is limited. After melting and forging, this F82H-BA12 heat was heat-treated in four different conditions to consider their fluctuations and to optimize them, and tensile and Charpy impact tests were then performed. The result of these mechanical properties were comparable to those of former F82H heats less than 5 tons which were melted applying vacuum induction melting.

  14. The effects of acetylation on properties of flax fibre and its polypropylene composites

    Directory of Open Access Journals (Sweden)

    2008-06-01

    Full Text Available Flax fibre was modified with acetylation. The influence of the acetylation on the structure and properties of flax fibre were investigated as well as modified flax fibre reinforced polypropylene composites were also prepared. The catalyst was used to accelerate acetylation reaction rate. Flax fibre was characterised after modification. Surface morphology, moisture absorption property, components content, degree of polymerisation, crystallinity of cellulose and thermal stability of flax fibres were studied. Due to acetylation, the flax fibre surface morphology and moisture resistance properties improved remarkably. Flax fibre (modified and unmodified reinforced polypropylene composites were fabricated with 30 wt% fibre loading. The mechanical properties were investigated for those composites. Tensile and flexural strengths of composites were found to increase with increasing degree of acetylation up to 18% and then decreased. Charpy impact strengths of composites were found to decrease with increasing degree of acetylation. Owing to addition of coupling agent (maleated polypropylene -MAH, the tensile and flexural strength properties were found to increase in between 20 to 35% depending on degree of acetylation.

  15. An atomistic modelling of the porosity impact on UO{sub 2} matrix macroscopic properties

    Energy Technology Data Exchange (ETDEWEB)

    Jelea, A., E-mail: andrei.jelea@irsn.fr [Institut de Radioprotection et de Surete Nucleaire (IRSN), DPAM, SEMCA, LEC, Cadarache (France); Centre Interdisciplinaire des Nanosciences de Marseille, CNRS, Campus de Luminy, Marseille 13288 (France); Institute of Physical Chemistry Ilie Murgulescu, Romanian Academy, 202 Spl Independentei St., 060021 Bucharest-12 (Romania); Colbert, M. [Institut de Radioprotection et de Surete Nucleaire (IRSN), DPAM, SEMCA, LEC, Cadarache (France); Centre Interdisciplinaire des Nanosciences de Marseille, CNRS, Campus de Luminy, Marseille 13288 (France); Ribeiro, F. [Institut de Radioprotection et de Surete Nucleaire (IRSN), DPAM, SEMCA, LEC, Cadarache (France); Treglia, G. [Centre Interdisciplinaire des Nanosciences de Marseille, CNRS, Campus de Luminy, Marseille 13288 (France); Pellenq, R.J.-M. [Centre Interdisciplinaire des Nanosciences de Marseille, CNRS, Campus de Luminy, Marseille 13288 (France); Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2011-08-15

    Highlights: > The porosity impact on the UO{sub 2} matrix thermomechanical properties was investigated. > Atomistic simulation techniques were used in this study. > The UO{sub 2} thermal expansion coefficient is modified due to the pore surface effects. > The elastic moduli at 0 K and at finite temperature decrease linearly with porosity. - Abstract: The porosity impact on the UO{sub 2} matrix thermomechanical properties was investigated using atomistic simulation techniques. The porosity modifies the thermal expansion coefficient and this is attributed to pore surface effects. The elastic moduli at 0 K and at finite temperature decrease with porosity, this variation being well approximated using affine functions. These results agree with other mesoscale model predictions and experimental data, showing the ability of the semiempirical potential atomistic simulations to give an overall good description of the porous UO{sub 2}. However, the surface effects are incompletely described.

  16. Dynamic-Mechanical and Impact Properties of Conductive Polymer Blends Based on Polypropylene

    Science.gov (United States)

    Acierno, Domenico; Russo, Pietro

    2007-04-01

    Plastic materials with significant electrical properties are getting more and more interest as witnessed by the wide spectra of industrial applications such as high performance textiles, fabrics for military, electronics and display technologies, automotive field (fuel delivery lines, exterior body panels) and so on. In this context, in the last decade an increasing interest has been devoted to the use of intrinsically conductive polymers such as polyaniline (PANI). In this work melt blended formulations based on polypropylene, containing 5% and 10% by weight of PANI, were investigated in terms of dynamic-mechanical and impact properties. Preliminary results indicate that, besides the processing conditions, inclusions of PANI make a general worsening of the dumping behaviour, especially in the rubbery region. Anyway, it is evident a clear improvement of the impact resistance with respect to the matrix, processed under the same conditions and taken as a reference, for the 5wt % system.

  17. Phenolic rigid organic filler/isotactic polypropylene composites. Ⅲ. Impact resistance property

    Institute of Scientific and Technical Information of China (English)

    Heming LIN; Dongming QI; Jian HAN; Zhiqi CAI; Minghua WU

    2009-01-01

    A novel phenolic rigid organic filler (KT) was used to modify isotactic polypropylene (iPP). The influence of KT particles on the impact resistance property of PP/KT specimens (with similar interparticles distance, 1.8 μm) was studied by notched izod impact tests. It was found that the brittle-ductile transition (BDT) of the PP/KT microcomposites took place at the filler content of about 4%, and the impact strength attains the maximum at 5% (with filler particles size of 1.5 μm), which is about 2.5 times that of unfilled iPP specimens. The impact fracture morphology was investigated by scanning electron microscopy (SEM). For the PP/KT specimens and the high-density polyethylene/KT (HDPE/KT) specimens in ductile fracture mode, many microfibers could be found on the whole impact fracture surface. It was the filler particles that induced the plastic deformation of interparticles ligament and hence improved the capability of iPP matrix on absorbing impact energy dramatically. The determinants on the BDT were further discussed on the basis of stress concentration and debonding resistance. It can be concluded that aside from the interparticle distance, the filler particles size also plays an important role in semicrystal-line polymer toughening.

  18. Multi-scale analysis of the impact of polylactide morphology on gas barrier properties

    OpenAIRE

    Fernandes Nassar, Samira; Guinault, Alain; Delpouve, Nicolas; Divry, Véronique; Sollogoub, Cyrille

    2017-01-01

    Semicrystalline polylactide (PLA) films with controlled morphology were produced by thermal crystallization to optimize the oxygen barrier properties. The crystalline morphology of PLA at the scales of the lamella and the spherulite was investigated and the mobile amorphous phase dynamics were studied. The crystalline morphology had a negligible impact on the oxygen diffusion coefficient. The occurrence of a rigid amorphous fraction (RAF) in the amorphous phase due to its insufficient decoupl...

  19. Corn Stover Impacts on Near-Surface Soil Properties of No-Till Corn In Ohio

    Energy Technology Data Exchange (ETDEWEB)

    Blanco-Canqui, H; Lal, Rattan; Post, W M.; Izaurralde, R Cesar C.; Owens, L B.

    2006-01-06

    Corn stover is a primary biofuel feedstock and its expanded use could help reduce reliance on fossil fuels and net CO2 emissions. Excessive stover removal may, however, negatively impact near-surface soil properties within a short period after removal. We assessed changes in soil crust strength, bulk density, and water content over a 1-yr period following a systematic removal or addition of stover from three no-till soils under corn in Ohio.

  20. Experimental study of dynamic mechanical properties of reactive powder concrete under high-strain-rate impacts

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The dynamic mechanical properties of reactive powder concrete subjected to compressive impacts with high strain rates ranging from 10 to 1.1×102 s-1 were investigated by means of SHPB (split-Hopkinson-pressure-bar) tests of the cylindrical specimens with five different steel fiber volumetric fractions.The properties of wave stress transmission,failure,strength,and energy consumption of RPC with varied fiber volumes and impact strain rates were analyzed.The influences of impact strain rates and fiber volumes on those properties were characterized as well.The general forms of the dynamic stress-strain relationships of RPC were modeled based on the experimental data.The investigations indicate that for the plain RPC the stress response is greater than the strain response,showing strong brittle performance.The RPC with a certain volume of fibers sustains higher strain rate impact and exhibits better deformability as compared with the plain RPC.With a constant fiber fraction,the peak compressive strength,corresponding peak strain and the residual strain of the fiber-reinforced RPC rise by varying amounts when the impact strain rate increases,with the residual strain demonstrating the greatest increment.Elevating the fiber content makes trivial contribution to improving the residual deformability of RPC when the impact strain rate is constant.The tests also show that the fiber content affects the peak compressive strength and the peak deformability of RPC in a different manner.With a constant impact strain rate and the fiber fraction less than 1.75%,the peak compressive strength rises with an increasing fiber volume.The peak compressive strength tends to decrease as the fiber volume exceeds 1.75%.The corresponding peak strain,however,incessantly rises with the increasing fiber volume.The total energy Edisp that RPC consumed during the period from the beginning of impacts to the time of residual strains elevates with the fiber volume increment as long as the fiber

  1. Study on comprehensive properties of duplex austenitic surfacing alloys for impacting abrasion

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, comprehensive property crack resistance, work hardening and abrasion resistance of a series of double-phases austenitic alloys(FAW) has been studied by means of SEM, TEM and type MD-10 impacting wear test machine. FAW alloys are of middle chromium and low manganese, including Fe-Cr-Mo-C alloy,Fe-Cr-Mn-C alloy and Fe-Cr-Mn-Ni-C alloy, that are designed for working in condition of impacting abrasion resistance hardfacing.Study results show that the work hardening mechanism of FAW alloys are mainly deformation high dislocation density and dynamic carbide aging, the form of wearing is plastic chisel cutting. Adjusting the amount of carbon, nickel, manganese and other elements in austenitic phase area, the FAW alloy could fit different engineering conditions of high impacting, high temperature and so on.

  2. Influence of Surface Properties and Impact Conditions on Adhesion of Insect Residues

    Science.gov (United States)

    Wohl, Christopher J.; Smith, Joseph G.; Connell, John W.; Siochi, Emilie J.; Doss, Jereme R.; Shanahan, Michelle H.; Penner, Ronald K.

    2015-01-01

    Insect residues can cause premature transition to turbulent flow on laminar flow airfoils. Engineered surfaces that mitigate the adhesion of insect residues provide, therefore, a route to more efficient aerodynamics and reduced fuel burn rates. Areal coverage and heights of residues depend not only on surface properties, but also on impact conditions. We report high speed photography of fruit fly impacts at different angles of inclination on a rigid aluminum surface, optical microscopy and profilometry, and contact angle goniometry to support the design of engineered surfaces. For the polyurethane and epoxy coatings studied, some of which exhibited superhydrophobicity, it was determined that impact angle and surface compositions play critical roles in the efficacy of these surfaces to reduce insect residue adhesion.

  3. Impact of annealing on electrical properties of Cu2ZnSnSe4 absorber layers

    Science.gov (United States)

    Weiss, Thomas Paul; Redinger, Alex; Rey, Germain; Schwarz, Torsten; Spies, Maria; Cojocura-Mirédin, Oana; Choi, P.-P.; Siebentritt, Susanne

    2016-07-01

    Reported growth processes for kesterite absorber layers generally rely on a sequential process including a final high temperature annealing step. However, the impact and details for this annealing process vary among literature reports and little is known on its impact on electrical properties of the absorber. We used kesterite absorber layers prepared by a high temperature co-evaporation process to explicitly study the impact of two different annealing processes. From electrical characterization it is found that the annealing process incorporates a detrimental deep defect distribution. On the other hand, the doping density could be reduced leading to a better collection and a higher short circuit current density. The activation energy of the doping acceptor was studied with admittance spectroscopy and showed Meyer-Neldel behaviour. This indicates that the entropy significantly contributes to the activation energy.

  4. Mechanical performance of carbon-epoxy laminates. Part I: quasi-static and impact bending properties

    Directory of Open Access Journals (Sweden)

    José Ricardo Tarpani

    2006-06-01

    Full Text Available In Part I of this study, quasi-static and impact bending properties of four aeronautical grade carbon-epoxy laminates have been determined and compared. Materials tested were unidirectional cross-ply (tape and bidirectional woven textile (fabric carbon fiber lay-up architectures, impregnated with standard and rubber-toughened resins, respectively, giving rise to 1.5 mm-thick laminates. Quasi-static mechanical properties assessed in transversal mode loading were modulus of elasticity, flexural strength and tenacity at the maximum load, whereas the net absorbed energy was determined under translaminar impact conditions. Two-dimensional woven carbon fiber reinforcements embedded in a rubber-toughened matrix presented the best mechanical performance under static loading. Under dynamic loading conditions, woven fiber fabric pre-forms were favorably sensitive to increasing impact energies regardless the nature of the employed epoxy resin. However, it was concluded that great care should be taken with this material within the low energy impact regimen.

  5. Effects of surface properties on the impact process of a yield stress fluid drop

    Energy Technology Data Exchange (ETDEWEB)

    Saidi, Alireza [UMR 5518 CNRS-Grenoble Institut Polytechnique (Grenoble INP), Laboratory of Pulp and Paper Science and Graphic Arts (LGP2), St Martin d' Heres (France); Martin, Celine [UMR 5518 CNRS-Grenoble Institut Polytechnique (Grenoble INP), Laboratory of Pulp and Paper Science and Graphic Arts (LGP2), St Martin d' Heres (France); Universite Joseph Fourier Grenoble I, CNRS, Laboratoire de Rheologie, CNRS UMR 5520, Grenoble Institut Polytechnique, BP 53, Grenoble Cedex 9 (France); Magnin, Albert [Universite Joseph Fourier Grenoble I, CNRS, Laboratoire de Rheologie, CNRS UMR 5520, Grenoble Institut Polytechnique, BP 53, Grenoble Cedex 9 (France)

    2011-07-15

    The impact of a yield stress fluid drop onto a solid surface with diversified interface properties has been experimentally investigated. Two smooth substrates with distinct surface energies and three similar substrates with different roughnesses have been used. The bulk shear rheological behaviour of Carbopol gels, concentrated suspensions of swollen micro-gels, has been measured. Wall friction has also been characterized on each substrate. Slip effects of gels proved to be greater on a more hydrophobic substrate. They decreased with an increase in roughness. The drop hydrodynamics during the impact was correlated with the wall friction of the gels on all substrates and with the ratio of surface roughness to size of the swollen micro-gels. At very low impact velocities, the gravitational subsidence amplitude depends greatly on surface properties. At higher impact velocities, no significant difference is observed during the spreading phase. The drop behaviour differs during the retraction depending on the substrate. Interface effects during the retraction stage proved to diminish when the yield stress value increases. (orig.)

  6. Lunar Crustal Properties: Insights from the GRAIL Gravity Signatures of Lunar Impact Craters

    Science.gov (United States)

    Soderblom, J. M.; Andrews-Hanna, J. C.; Evans, A. J.; Johnson, B. C.; Melosh, J., IV; Milbury, C.; Miljkovic, K.; Nimmo, F.; Phillips, R. J.; Smith, D. E.; Solomon, S. C.; Wieczorek, M. A.; Zuber, M. T.

    2014-12-01

    Impact cratering is a violent process, shattering and melting rock and excavating deep-seated material. The resulting scars are apparent on every planetary surface across our Solar System. Subsurface density variations associated with the resulting impact structures contain clues to aid in unlocking the details of this process. High-resolution gravity fields, such as those derived from the Gravity Recovery and Interior Laboratory (GRAIL) mission, are ideal for investigating these density variations. With gravity measurements from GRAIL and topography from the Lunar Orbiter Laser Altimeter (LOLA), we derived high-resolution Bouguer gravity fields (i.e., the gravity field after the contribution from topography is removed) that we correlated with craters mapped from LOLA data. We found that the mass deficit beneath lunar impact craters relates directly to crater size, up to diameter ~130 km, whereas craters larger than this diameter display no further systematic change. This observation, coupled with the greater depth of impact damage expected beneath larger craters, indicates that some process is affecting the production and/or preservation of porosity at depth or otherwise altering the mean density beneath the larger craters (note, measurable mantle uplift is observed for craters larger than ~184-km diameter). The observed crater gravity anomalies, however, exhibit considerable variation about these mean trends, suggesting that other factors are also important in determining the bulk density of impact crater structures. Milbury et al. (this conference) have demonstrated that pre-impact crustal porosity strongly influences the resulting density contrast between the impact damage zone beneath a crater and its surroundings. Herein, we extend these studies using the same GRAIL- and LOLA-derived maps to further investigate the effects that crustal properties have on the bulk density of the rock beneath lunar impact features. We focus, in particular, on the processes that

  7. Effect of thermal exposure on mechanical properties hypo eutectic aerospace grade aluminium-silicon alloy

    Science.gov (United States)

    Nagesh Kumar, R.; Ram Prabhu, T.; Siddaraju, C.

    2016-09-01

    The effect of thermal exposure on the mechanical properties of a C355.0 aerospace grade aluminum-silicon alloy (5% Si - 1.2% Cu - 0.5% Mg) was investigated in the present study. The alloy specimens were subjected to T6 (solution treatment and artificial ageing treatment) temper treatment to enhance the strength properties through precipitation hardening. The T6 temper treatment involved solution heat treatment at 520oC for 6h, followed by water quenching and ageing at 150oC. After the heat treatment, the specimens were exposed to various temperatures (50oC, 100oC, 150oC, 200oC and 250oC) for 5 and 10 h to study the structural applications of this alloy to the various Mach number military aircrafts. After the thermal exposure, specimens were tested for tensile, hardness and impact properties (Charpy). The microstructure of the thermal exposed specimens was examined in the optical microscopes and correlated with the mechanical properties results. In summary, an increase of exposure time has a different effect on the tensile and hardness properties of the alloy. For the exposure time 5h, the tensile and hardness properties increase upto 100oC and later decrease with an increase of temperature. In contrast, the tensile and hardness properties linearly decrease with an increase of temperature. Several factors such as matrix grain growth, diffusion rate, Si particles size and distribution, precipitate stability play a key role on deciding the tensile properties of the alloy. Comparing the relative effects of temperature and time, the temperature effects dominate more in deteriorating tensile properties of the alloy. There are no effects of exposure temperature and/or time on the impact properties of the alloy.

  8. Impact of the post fire management in some soil chemical properties. First results.

    Science.gov (United States)

    Francos, Marcos; Pereira, Paulo; Alcañiz, Meritxell; Úbeda, Xavi

    2016-04-01

    Post-fire management after severe wildfires has impact on soil properties. In Mediterranean environments management of fire affected areas is a common practice. This intervention may change soil chemical properties of the soil such as major cations. The aim of this work is to study the impact of different types of forest management in soil extractable calcium, magnesium, sodium and potassium after a severe wildfire. The study area is located in Ódena (Catalonia, Spain). The wildfire occurred at July 27th of 2015 and burned 1235 ha. After the fire an experimental plot was designed 9 plots with 2x2 meters (4 square meters). The different managements were: a) clear-cuted area and wood removed, b) no treatment); and c) clear-cutted. The results of the first sampling showed significant differences among all treatments in extractable calcium, sodium and potassium. The amount of these extractable elements was high in clear-cutted treatment in comparison to the others. No differences were identified in extractable magnesium. Overall, in the immediate period after the fire, burned area management, changed the studied soil properties. We are currently studying the evolution of this soil properties in these plots with the time

  9. Impact Properties of Engineered Cementitious Composites with High Volume Fly Ash Using SHPB Test

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhitao; YANG Yingzi; YAO Yan

    2012-01-01

    The split Hopkinson pressure bar (SHPB) testing with diameter 40 mm was used to investigate the dynamic mechanical properties of engineered cementitious composites (ECCs) with different fly ash content.The basic properties including deformation,energy absorption capacity,strain-stress relationship and failure patterns were discussed.The ECCs showed strain-rate dependency and kept better plastic flow during impact process compared with reactive powder concrete (RPC) and concrete,but the critical compressive strength was lower than that of R-PC and concrete.The bridging effect of PVA fiber and addition of fly ash can significantly improve the deformation and energy absorption capacities of ECCs.With the increase of fly ash content in ECCs,the static and dynamic compressive strength lowered and the dynamic increase factor enhanced,Therefore,to meet different engineering needs,the content of fly ash can be an important index to control the static and dynamic mechanical properties of ECCs.

  10. The impact of the chemical synthesis on the magnetic properties of intermetallic PdFe nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Castellanos-Rubio, I.; Insausti, M.; Muro, I. Gil de [Universidad del País Vasco, UPV/EHU, Dpto. de Química Inorgánica (Spain); Arias-Duque, D. Carolina; Hernández-Garrido, Juan Carlos [Universidad de Cadiz, Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica, Facultad de Ciencias (Spain); Rojo, T.; Lezama, L., E-mail: luis.lezama@ehu.es [Universidad del País Vasco, UPV/EHU, Dpto. de Química Inorgánica (Spain)

    2015-05-15

    Palladium-rich Iron nanoparticles in the 4–8 nm range have been produced by a combination of two methods: the thermal decomposition of organometallic precursors and the reduction of metallic salts by a polyol. Herein, it is shown how the details of the synthesis have a striking impact on the magnetic and morphological properties of the final products. In the synthesis of these bimetallic nanoparticles, the use of high reaction temperatures plays an essential role in attaining good chemical homogeneity, which has proved to have a key influence on the magnetic properties. Magnetic characterization has been performed by electron magnetic resonance and magnetization measurements, which have confirmed the superparamagnetic-like behavior at room temperature. No clear traces of magnetic polarization in palladium atoms have been detected. The combination of long-term stability and homogeneous chemical and magnetic properties makes these particles very suitable for a wide range of applications in nanotechnology.

  11. 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

  12. Ballistic Impact Properties of Zr-Based Amorphous Alloy Composites Reinforced with Woven Continuous Fibers

    Science.gov (United States)

    Kim, Gyeong Su; Son, Chang-Young; Lee, Sang-Bok; Lee, Sang-Kwan; Song, Young Buem; Lee, Sunghak

    2012-03-01

    This study aims at investigating ballistic impact properties of Zr-based amorphous alloy (LM1 alloy) matrix composites reinforced with woven stainless steel or glass continuous fibers. The fiber-reinforced composites with excellent fiber/matrix interfaces were fabricated without pores and misinfiltration by liquid pressing process, and contained 35 to 41 vol pct of woven continuous fibers homogeneously distributed in the amorphous matrix. The woven-STS-continuous-fiber-reinforced composite consisted of the LM1 alloy layer of 1.0 mm in thickness in the upper region and the fiber-reinforced composite layer in the lower region. The hard LM1 alloy layer absorbed the ballistic impact energy by forming many cracks, and the fiber-reinforced composite layer interrupted the crack propagation and blocked the impact and traveling of the projectile, thereby resulting in the improvement of ballistic performance by about 20 pct over the LM1 alloy. According to the ballistic impact test data of the woven-glass-continuous-fiber-reinforced composite, glass fibers were preferentially fragmented to form a number of cracks, and the amorphous matrix accelerated the fragmentation of glass fibers and the initiation of cracks. Because of the absorption process of ballistic impact energy by forming very large amounts of cracks, fragments, and debris, the glass-fiber-reinforced composite showed better ballistic performance than the LM1 alloy.

  13. Investigation on Impact Strength Properties of Kevlar Fabric using Different Shear Thickening Fluid Composition

    Directory of Open Access Journals (Sweden)

    R. Joselin

    2014-05-01

    Full Text Available Great interest has aroused in developing high impact resistant fabrics based on the incorporation of a shear thickening fluid (STF into high performance fabrics (Kevlar. This work developed a shear thickening fluid enhanced fabrics and the influence of the shear thickening fluid types against spike impact and the impact resistance performance were investigated. Silica nano-particle impregnated Kevlar fabrics exhibit significantly enhanced ballistic performance while retaining flexibility. It was found that fabrics impregnated with functionalized nanoparticles offer multiple resistance to the penetration of a sharp impactor. The improvement in protection is traced by the formation of siloxane bonds during functionalization. It exhibits significant improvement in shear stiffness and aslight increase in tensile stiffness. The impact strength properties of all samples were tested using impact testingand quasi-static testing apparatuses. Chemical compositions and microscopic structures were analyzed with Fouriertransform infrared spectroscopy and scanning electron microscopy. The current study clearly displays a significant enhancement in penetration resistance of Kevlar fabric impregnated with different combination of STF’s.Defence Science Journal, Vol. 64, No. 3, May 2014, pp. 236-243, DOI:http://dx.doi.org /10.14429/dsj.64.7322

  14. The correlation of low-velocity impact resistance of graphite-fiber-reinforced composites with matrix properties

    Science.gov (United States)

    Bowles, K. J.

    1986-01-01

    Summarized are basic studies that were conducted to correlate the impact resistance of graphite-fiber-reinforced composites with polymer matrix properties. Three crosslinked epoxy resins and a linear polysulfone were selected as composite matrices. As a group, these resins possess a significantly large range of mechanical properties. The mechanical properties of the resins and their respective composites were measured. Neat resin specimens and unidirectional and crossply composite specimens were impact tested with an instrumented dropweight tester. Impact resistances of the specimens were assessed on the basis of loading capability, energy absorption, and extent of damage.

  15. Dynamical properties measurements for asteroid, comet and meteorite material applicable to impact modeling and mitigation calculations

    Energy Technology Data Exchange (ETDEWEB)

    Furnish, M.D.; Boslough, M.B. [Sandia National Labs., Albuquerque, NM (United States); Gray, G.T. III [Los Alamos National Lab., NM (United States); Remo, J.L. [Quantametrics, Inc., St. James, NY (United States)

    1994-07-01

    We describe methods for measuring dynamical properties for two material categories of interest in understanding large-scale extraterrestrial impacts: iron-nickel and underdense materials (e.g. snow). Particular material properties measured by the present methods include Hugoniot release paths and constitutive properties (stress vs. strain). The iron-nickel materials lend themselves well to conventional shock and quasi-static experiments. As examples, a suite of experiments is described including six impact tests (wave profile compression/release) over the stress range 2--20 GPa, metallography, quasi-static and split Hopkinson pressure bar (SHPB) mechanical testing, and ultrasonic mapping and sound velocity measurements. Temperature sensitivity of the dynamic behavior was measured at high and low strain rates. Among the iron-nickel materials tested, an octahedrite was found to have behavior close to that of Armco iron under shock and quasi-static conditions, while an ataxite exhibited a significantly larger quasi-static yield strength than did the octahedrite or a hexahedrite. The underdense materials pose three primary experimental difficulties. First, the samples are friable; they can melt or sublimate during storage, preparation and testing. Second, they are brittle and crushable; they cannot withstand such treatment as traditional machining or launch in a gun system. Third, with increasing porosity the calculated Hugoniot density becomes rapidly more sensitive to errors in wave time-of-arrival measurements. Carefully chosen simulants eliminate preservation (friability) difficulties, but the other difficulties remain. A family of 36 impact tests was conducted on snow and snow simulants at Sandia, yielding reliable Hugoniot and reshock states, but limited release property information. Other methods for characterizing these materials are discussed.

  16. Dynamical properties measurements for asteroid, comet and meteorite material applicable to impact modeling and mitigation calculations

    Science.gov (United States)

    Furnish, M. D.; Boslough, M. B.; Gray, G. T., III; Remo, J. L.

    We describe methods for measuring dynamical properties for two material categories of interest in understanding large-scale extraterrestrial impacts: iron-nickel and underdense materials (e.g. snow). Particular material properties measured by the present methods include Hugoniot release paths and constitutive properties (stress vs. strain). The iron-nickel materials lend themselves well to conventional shock and quasi-static experiments. As examples, a suite of experiments is described including six impact tests (wave profile compression/release) over the stress range 2-20 GPa, metallography, quasi-static and split Hopkinson pressure bar (SHPB) mechanical testing, and ultrasonic mapping and sound velocity measurements. Temperature sensitivity of the dynamic behavior was measured at high and low strain rates. Among the iron-nickel materials tested, an octahedrite was found to have behavior close to that of Armco iron under shock and quasi-static conditions, while an ataxite exhibited a significantly larger quasi-static yield strength than did the octahedrite or a hexahedrite. The underdense materials pose three primary experimental difficulties. First, the samples are friable; they can melt or sublimate during storage, preparation and testing. Second, they are brittle and crushable; they cannot withstand such treatment as traditional machining or launch in a gun system. Third, with increasing porosity the calculated Hugoniot density becomes rapidly more sensitive to errors in wave time-of-arrival measurements. Carefully chosen simulants eliminate preservation (friability) difficulties, but the other difficulties remain. A family of 36 impact tests was conducted on snow and snow simulants at Sandia, yielding reliable Hugoniot and reshock states, but limited release property information. Other methods for characterizing these materials are discussed.

  17. Evaluation of flow properties in the weldments of vanadium alloys using a novel indentation technique

    Energy Technology Data Exchange (ETDEWEB)

    Gubbi, A.N.; Rowcliffe, A.F.; Lee, E.H.; King, J.F.; Goodwin, G.M. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    Automated Ball Indentation (ABI) testing, was successfully employed to determine the flow properties of the fusion zone, heat affected zone (HAZ), and base metal of the gas tungsten arc (GTA) and electron beam (EB) welds of the V-4Cr-4Ti (large heat no. 832665) and the V-5Cr-5Ti (heat 832394) alloys. ABI test results showed a clear distinction among the properties of the fusion zone, HAZ, and base metal in both GTA and EB welds of the two alloys. GTA and EB welds of both V-4Cr-4Ti and V-5Cr-5Ti alloys show strengthening of both the fusion zone and the HAZ (compared to base metal) with the fusion zone having higher strength than the HAZ. These data correlate well with the Brinell hardness. On the other hand, GTA welds of both alloys, after a post-weld heat treatment of 950{degrees}C for 2 h, show a recovery of the properties to base metal values with V-5Cr-5Ti showing a higher degree of recovery compared to V-4Cr-4Ti. These measurements correlate with the reported recovery of the Charpy impact properties.

  18. Long-term properties of reduced activation ferritic/martensitic steels for fusion reactor blanket system

    Energy Technology Data Exchange (ETDEWEB)

    Shiba, Kiyoyuki, E-mail: Shiba.kiyoyuki@jaea.go.jp [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Tanigawa, Hiroyasu; Hirose, Takanori; Sakasegawa, Hideo; Jitsukawa, Shiro [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)

    2011-12-15

    Thermal aging properties of reduced activation ferritic/martensitic steel F82H was researched. The aging was performed at temperature ranging from 400 Degree-Sign C to 650 Degree-Sign C up to 100,000 h. Microstructure, precipitates, tensile properties, and Charpy impact properties were carried out on aged materials. Laves phase was found at temperatures between 550 and 650 Degree-Sign C and M{sub 6}C type carbides were found at the temperatures between 500 and 600 Degree-Sign C over 10,000 h. These precipitates caused degradation in toughness, especially at temperatures ranging from 550 Degree-Sign C to 650 Degree-Sign C. Tensile properties do not have serious aging effect, except for 650 Degree-Sign C, which caused large softening even after 10,000 h. Increase of precipitates also causes some degradation in ductility, but it is not critical. Large increase in ductile-to-brittle transition temperature was observed in the 650 Degree-Sign C aging. It was caused by the large Laves phase precipitation at grain boundary. Laves precipitates at grain boundary also degrades the upper-shelf energy of the aged materials. These aging test results indicate F82H can be used up to 30,000 h at 550 Degree-Sign C.

  19. 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.

  20. IMPACT OF TIME / TEMPERATURE CURING CONDITIONS AND ALUMINATE CONCENTRATIONS ON SALTSTONE PROPERTIES

    Energy Technology Data Exchange (ETDEWEB)

    Harbour, J.; Edwards, T.; Williams, V.

    2009-05-05

    This report addresses the impact of (1) the time and temperature curing conditions (profile) and (2) the impact of higher aluminate concentrations in the decontaminated salt solution on Saltstone processing and performance properties. The results demonstrate that performance properties as well as some of the processing properties of Saltstone are highly sensitive to the conditions of time and temperature under which curing occurs. This sensitivity is in turn dependent on the concentration of aluminate in the salt feed solution. In general, the performance properties and indicators (Young's modulus, compressive strength and total porosity) are reduced when curing is initially carried out under high temperature. However, this reduction in performance properties is dependent on the sequence of temperatures (the time/temperature profile) experienced during the curing process. That is, samples that are subjected to a 1, 2, 3 or 4 day curing time at 60 C followed by final curing at 22 C lead to performance properties that are significantly different than the properties of grouts allowed to cure for 1, 2, 3 or 4 days at 22 C followed by a treatment at 60 C. The performance properties of Saltstone cured in the sequence of higher temperature first are generally less (and in some cases significantly less) than performance properties of Saltstone cured only at 22 C. This loss in performance was shown to be mitigated by increased slag content or cement content in the premix at the expense of fly ash. For the sequence in which the Saltstone is initially cured at 22 C followed by a higher temperature cure, the performance properties can be equal to or greater than the properties observed with curing only at 22 C curing. The results in this report indicate that in order to meaningfully measure and report the performance properties of Saltstone, one has to know the time/temperature profile conditions under which the Saltstone will be cured. This will require thermal modeling

  1. IMPACT OF ALUMINATE IONS ON THE PROPERTIES OF SALTSTONE GROUT MIXES

    Energy Technology Data Exchange (ETDEWEB)

    Harbour, J; Tommy Edwards, T; Erich Hansen, E; Vickie Williams, V

    2008-02-21

    It is important to identify and control the operational and compositional variables that impact the important processing and performance properties of Saltstone grout mixes. The grout that is produced at the Saltstone Production Facility (SPF) is referred to as Saltstone and is a waste form that immobilizes low concentrations of radionuclides as well as certain toxic metals. The Saltstone will be disposed of in vaults at Savannah River Site (SRS). An effort referred to as the Saltstone Variability Study has been initiated to achieve this goal. The protocols developed in this variability study are also ideally suited as a tool to assess the impact of proposed changes to the processing flow sheet for Liquid Waste Operations at SRS. One such proposal that is currently under consideration is to introduce a leaching step in the treatment of the High Level Waste (HLW) sludge to remove aluminum prior to vitrification at the Defense Waste Processing Facility (DWPF). This leachate would significantly increase the soluble aluminate concentration in the salt feed that will be processed at the SPF. Consequently, an initial study of the impact of increased aluminate concentration on the Saltstone grout properties was performed. Prior work by Lukens (1) showed that aluminate in the salt solutions increases the amount of heat generation.

  2. Impact of morphology on the radiative properties of fractal soot aggregates

    Science.gov (United States)

    Doner, Nimeti; Liu, Fengshan

    2017-01-01

    The impact of morphology on the radiative properties of fractal soot aggregates was investigated using the discrete dipole approximation (DDA). The optical properties of four different types of aggregates of freshly emitted soot with a fractal dimension Df=1.65 and a fractal pre-factor kf=1.76 were calculated. The four types of aggregates investigated are formed by uniform primary particles in point-touch, by uniform but overlapping primary particles, by uniform but enlarged primary particles in point-touch, and formed by point-touch and polydisperse primary particles. The radiative properties of aggregates consisting of N=20, 56 and 103 primary particles were numerically evaluated for a given refractive index at 0.532 and 1.064 μm. The radiative properties of soot aggregates vary strongly with the volume equivalent radius aeff and wavelength. The accuracy of DDA was evaluated in the first and fourth cases against the generalized multi-sphere Mie (GMM) solution in terms of the vertical-vertical differential scattering cross section (Cvv). The model predicted the average relative deviations from the base case to be within 15-25% for Cvv, depending on the number of particles for the aggregate. The scattering cross sections are only slightly affected by the overlapping but more significantly influenced by primary particle polydispersity. It was also found that the enlargement of primary particles by 20% has a strong effect on soot aggregate radiative properties.

  3. Temporal Variability of Aerosol Properties during TCAP: Impact on Radiative Forcing

    Energy Technology Data Exchange (ETDEWEB)

    Kassianov, Evgueni I.; Barnard, James C.; Pekour, Mikhail S.; Berg, Larry K.; Fast, Jerome D.; Michalsky, Joseph J.; Lantz, K.; Hodges, G. B.

    2013-11-01

    Ground-based remote sensing and in situ observations of aerosol microphysical and optical properties have been collected during summertime (June-August, 2012) as part of the Two-Column Aerosol Project (TCAP; http://campaign.arm.gov/tcap/), which was supported by the U.S. Department of Energy’s (DOE’s) Atmospheric Radiation Measurement (ARM) Program (http://www.arm.gov/). The overall goal of the TCAP field campaign is to study the evolution of optical and microphysical properties of atmospheric aerosol transported from North America to the Atlantic and their impact on the radiation energy budget. During TCAP, the ground-based ARM Mobile Facility (AMF) was deployed on Cape Cod, an arm-shaped peninsula situated on the easternmost portion of Massachusetts (along the east coast of the United States) and that is generally downwind of large metropolitan areas. The AMF site was equipped with numerous instruments for sampling aerosol, cloud and radiative properties, including a Multi-Filter Rotating Shadowband Radiometer (MFRSR), a Scanning Mobility Particle Sizer (SMPS), an Aerodynamic Particle Sizer (APS), and a three-wavelength nephelometer. In this study we present an analysis of diurnal and day-to-day variability of the column and near-surface aerosol properties obtained from remote sensing (MFRSR data) and ground-based in situ measurements (SMPS, APS, and nephelometer data). In particular, we show that the observed diurnal variability of the MFRSR aerosol optical depth is strong and comparable with that obtained previously from the AERONET climatology in Mexico City, which has a larger aerosol loading. Moreover, we illustrate how the variability of aerosol properties impacts the direct aerosol radiative forcing at different time scales.

  4. Study on Dynamic Mechanical Properties of Limestone under Uniaxial Impact Compressive Loads

    Directory of Open Access Journals (Sweden)

    Fei Zou

    2016-01-01

    Full Text Available The dynamic mechanical properties of limestone are studied with 5 types of impact pressure acting on limestone samples in axial direction in this paper. The rubber shaper with a diameter of 5 mm and thickness of 2 mm is adopted. Besides the conical punch of split pressure bar of Hopkinson with a diameter of 50 mm is also used. The half-sinusoid pulse is obtained by using the pulse shaper method and special punch method; the constant strain rate deformation of the sample is realized. Dynamic compressive properties and failure modes of limestone under different impact pressure are investigated. In addition, energy dissipation is studied in the process of experiment. The results show that the dynamic compressive strength of limestone has an exponent relation to strain rate. The failure strain, degree of fragmentation, incident energy, and absorption energy increase, while the energy absorbency decreases with the increasing of strain rate. However, the initial elastic modulus is not sensitive to the strain rate. The research method and conclusions have reference value for the dynamic mechanical properties of other brittle materials.

  5. 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.

  6. Global Geometric Properties of Martian Impact Craters: An Assessment from Mars Orbiter Laser Altimeter (MOLA) Digital Elevation Models

    Science.gov (United States)

    Garvin, J. B.; Frawley, J. J.; Sakimoto, S. E. H.; Schnetzler, C.

    2000-01-01

    Global geometric characteristics of topographically fresh impact craters have been assessed, for the first time, from gridded MOLA topography. Global trends of properties such as depth/diameter differ from previous estimates. Regional differences are observed.

  7. A study on the microstructure and mechanical properties of AISI D2 tool steel modified by niobium

    Energy Technology Data Exchange (ETDEWEB)

    Hamidzadeh, M.A.; Meratian, M. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Mohammadi Zahrani, M., E-mail: iut.mohammadi@gmail.com [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2012-10-30

    The microstructure and mechanical properties of AISI D2 tool steel with up to 1.5 wt% niobium additions were investigated. The microstructural evolutions were characterized by means of optical microscopy and scanning electron microscopy techniques. Mechanical properties of the samples were measured using tensile testing, hardness measurements and Charpy impact test. The results indicated that modification of the microstructure was effectively achieved through the addition of 1.5 wt% of niobium, which refined the prior-austenite grains and decreased the volume fraction of eutectic carbides. Also, the eutectic carbide network tended to break thereby forming blocky and ribbon-like morphologies in the eutectic structures. The ductility and impact toughness of the niobium-contained steels were increased considerably and reached to about 5.8% and 15 J/cm{sup 2}, respectively. Generally, the results of this study suggest that niobium can be used as an alloying element to significantly enhance the ductility and impact toughness of D2 tool steel without affecting the hardness.

  8. Environmental impact estimation of municipal solidwaste treatment based on their composition and properties

    Directory of Open Access Journals (Sweden)

    Il'inykh Galina Viktorovna

    2014-02-01

    Full Text Available Municipal solid waste (MSW is a significant environmental and sanitarian problem for urban areas. Different, often alternative, measures are considered in order to reduce the environmental impact of MSW management system, so adequate technique of comparative assessment of their environmental efficiency is needed. The problem is that waste composition, dangerous and organic matter content are often ignored when environmental impacts of MSW management system are calculated. Therefore, an algorithm of environmental impact estimation of municipal solid waste treatment based on their composition and properties is a question of considerable importance.The main difficulty in performing environmental impact calculation in compliance with MSW composition is the evaluation of the emissions per waste unit. Waste component content and biodegradable carbon content in every component are taken into account as basic waste features for emission estimation. Methane generation potential is calculated as a function of biodegradable carbon content.Environmental impacts of waste treatment on manual sorting plant in Yekaterinburg are given as an example. Waste composition analysis was carried out there in 2012. Material flow analysis allowed clarifying mass balance of the process. About 10 % of income waste mass are going out of the waste management system as a recyclables and determine the decreasing of environmental impacts. 1.24 % of biodegradable carbon don’t reach landfills, so it means that production of about ten cubic meters of biogas per ton of income MSW are prevented. When converting this data in money, it results in 47.1 rubles per ton of MSW or about 4.7 million rubles annually.

  9. Impact Wear Properties of Metal-Plastic Multilayer Composites Filled with Glass Fiber Treated with Rare Earth Element Surface Modifier

    Institute of Scientific and Technical Information of China (English)

    程先华; 薛玉君

    2001-01-01

    The friction and wear properties of metal-plastic multilayer composites filled with glass fiber, which is treated with rare earth element surface modifier, under impact load and dry friction conditions were investigated. Experimental results show that the metal-plastic multilayer composite filled with glass fiber exhibits excellent friction and impact wear properties when using rare earth elements as surface modifier for the surface treatment of glass fiber.

  10. Environmental Impacts on Spiking Properties in Hodgkin-Huxley Neuron with Direct Current Stimulus

    Institute of Scientific and Technical Information of China (English)

    YUAN Chang-Qing; ZHAO Tong-Jun; ZHAN Yong; ZHANG Su-Hua; LIU Hui; ZHANG Yu-Hong

    2009-01-01

    Based on the well accepted Hodgkin-Huxley neuron model, the neuronal intrinsic excitability is studied when the neuron is subject to varying environmental temperatures, the typical impact for its regulating ways. With computer simulation, it is found that altering environmental temperature can improve or inhibit the neuronal intrinsic excitability so as to influence the neuronal spiking properties. The impacts from environmental factors can be understood that ,the neuronal spiking threshold is essentially influenced by the fluctuations in the environ-ment. With the environmental temperature varying, burst spiking is realized for the neuronal membrane voltage because of the environment-dependent spiking threshold. This burst induced by changes in spiking threshold is different from that excited by input currents or other stimulus.

  11. Comparison of quasistatic to impact mechanical properties of multiwall carbon nanotube/polycarbonate composites

    Energy Technology Data Exchange (ETDEWEB)

    Brühwiler, Paul A.; Barbezat, Michel; Necola, Adly; Kohls, Doug J.; Bunk, Oliver; Schaefer, Dale W.; Pötschke, Petra (PSI); (EMMPA); (UCIN); (Leibniz)

    2010-10-22

    We report the quasistatic tensile and impact penetration properties (falling dart test) of injection-molded polycarbonate samples, as a function of multiwall carbon nanotube (MWNT) concentration (0.0-2.5%). The MWNT were incorporated by dilution of a commercial MWNT/polycarbonate masterbatch. The stiffness and quasistatic yield strength of the composites increased approximately linearly with MWNT concentration in all measurements. The energy absorbed in fracture was, however, a negative function of the MWNT concentration, and exhibited different dependencies in quasistatic and impact tests. Small-angle x-ray scattering (SAXS) showed that the dispersion of the MWNT was similar at all concentrations. The negative effects on energy absorption are attributed to agglomerates remaining in the samples, which were observed in optical microscopy and SAXS. Overall, there was a good correspondence between static and dynamic energy absorption.

  12. Effect of filler addition on the compressive and impact properties of glass fibre reinforced epoxy

    Indian Academy of Sciences (India)

    Nikhil Gupta; Balraj Singh Brar; Eyassu Woldesenbet

    2001-04-01

    Flyash is incorporated in glass fibre reinforced epoxies to study their response to the filler addition. Low cost of flyash can reduce the overall cost of the component. Only very low volume fractions of filler are investigated in the present study. To obtain further clarification of the observed phenomenon, another abundantly available low cost material, calcium carbonate is incorporated in one set of the specimens. Compressive strength of the material is found to decrease, whereas steep increase in impact strength is observed by introduction of very small quantity of fillers. Specimens containing calcium carbonate are tested for impact properties only. Effect of specimen aspect ratio on the compressive strength values is also studied by testing specimens of three different aspect ratios. Scanning electron microscopic observations are taken to develop a better understanding of the phenomena taking place in the material system at microscopic level.

  13. Mechanical properties of reactively flame retarded cyanate ester/epoxy resin blends and their carbon fibre reinforced composites

    Directory of Open Access Journals (Sweden)

    A. Toldy

    2016-12-01

    Full Text Available Cyanate ester/epoxy resin (CE/EP carbon fibre reinforced composites consisting of diglycidyl ether of bisphenol A (DGEBA and novolac type cyanate ester (CE were prepared and reactively flame retarded using epoxy functional adduct of DGEBA and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO. Effect of cyanate ester and flame retardant (FR ratio was determined on matrix viscosity, matrix and composite glass transition temperature (Tg, as well as composite mechanical properties including storage modulus, tensile, bending, interlaminar shear and Charpy impact properties. Although the epoxy resin (EP and FR decreased the Tg, even the flame retarded CE/EP blends had at least 22 °C higher Tg than the benchmark DGEBA composite. As for the mechanical properties, as a result of higher interlaminar shear strength suggesting better fibre-matrix adhesion, the CE/EP blends managed to over-perform the reference CE in most cases: The 2% phosphorus (P-containing CE/EP composite had 25% higher tensile strength than the CE reference. The bending strength of the blends remained in the same range as the reference, while the impact resistance significantly increased in comparison to CE, especially in flame retarded composites.

  14. Asteroid surface archaeology: Identification of eroded impact structures by spectral properties on (4) Vesta

    Science.gov (United States)

    Hoffmann, M.; Nathues, A.; Schäfer, M.; Schmedemann, N.; Vincent, J.; Russell, C.

    2014-07-01

    Introduction: Vesta's surface material is characterized as a deep regolith [1,2], mobilized by countless impacts. The almost catastrophic impact near Vesta's south pole, which has created the Rheasilvia basin, and the partly overlapping older impact of similar size, Veneneia, have not only reshaped the areas of their interior (roughly 50 % of the Vesta surface), but also emplaced each time a huge ejecta blanket of similar size, thus covering the whole remaining surface. In this context, pristine and even younger morphologic features have been erased. However, the spectral signatures of the early differentiation and alteration products by impacts have partially remained in situ. While near the north pole several large old eroded impact features are visible, the equatorial zone close to the basin rims seems to be void of those. Since it is unlikely, that this zone has been entirely avoided by large projectiles, in this area the results of such impacts may have left morphologically not detectable remnants: Individual distribution of particle sizes and altered photometric properties, excavated layers, shock metamorphism, melt generation inside particles and on macroscopic scales, and emplacement of exogenous projectile material. An analysis by color ratio images and spatial profiles of diagnostic spectral parameters reveals such features. Results: Based on local spectroscopic evidence we have detected eroded impact features of three categories: 1) Small craters with diameters of a few kilometers, 2) Large craters or, if even larger, incipient impact basins, 3) Sub-global ejecta blankets. The eastern part of Feralia Planitia, diameter 140 km, has little evidence of a round outline in the shape model, but it features spectral gradients towards its center. A feature of similar size, centered north of Lucaria Tholus becomes only visible by a similar spectra gradient and a circular outline in specific spectral ratio mosaics. These features seem to be related to the

  15. 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.

  16. 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.

  17. Effect of austenitizing conditions on the impact properties of an alloyed austempered ductile iron of initially ferritic matrix structure

    Energy Technology Data Exchange (ETDEWEB)

    Delia, M.; Alaalam, M.; Grech, M. [Univ. of Malta (Malta). Dept. of Metallurgy and Materials

    1998-04-01

    The effect of austenitizing conditions on the microstructure and impact properties of an austempered ductile iron (ADI) containing 1.6% Cu and 1.6% Ni as the main alloying elements was investigated. Impact tests were carried out on samples of initially ferritic matrix structure and which had been first austenitized at 850, 900, 950, and 1,000 C for 15 to 360 min and austempered at 360 C for 180 min. Results showed that the austenitizing temperature, T{sub {gamma}}, and time, t{sub {gamma}} have a significant effect on the impact properties of the alloy. This has been attributed to the influence of these variables on the carbon kinetics. Microstructures of samples austenitized at 950 and 1,000 C contain no pro-eutectoid ferrite. The impact properties of the former structures are independent of t{sub {gamma}}, while those solution treated at 1,000 C are generally low and show wide variation over the range of soaking time investigated. For fully ausferritic structures, impact properties fall with an increase in T{sub {gamma}}. This is particularly evident at 1,000 C. As the T{sub {gamma}} increases, the amount of carbon dissolved in the original austenite increases. This slows down the rate of austenite transformation and results in coarser structures with lower mechanical properties. Optimum impact properties are obtained following austenitizing between 900 and 950 C for 120 to 180 min.

  18. The impact of the manufacturing process on the hardness and sensory properties of milk chocolate

    OpenAIRE

    Zarić Danica B.; Pajin Biljana S.; Lončarević Ivana S.; Šoronja-Simović Dragana M.; Šereš Zita I.

    2012-01-01

    The aim of this paper was to examine the impact of the manufacturing process on the textural characteristics and sensory properties of milk chocolate. The research was conducted on the samples of chocolate produced in a ball mill during 30, 60 and 90 minutes of refining, each of them being pre-crystallized at 26, 28 and 30°C. A chocolate mass of identical ingredient composition was also produced using a standard manufacturing process at the same pre-crystallization temperatures. Chocola...

  19. Impact of forest fire on physical, chemical and biological properties of soil: A review

    OpenAIRE

    Satyam Verma; S Jayakumar

    2012-01-01

    Forest fire is very common to all the ecosystems of the world. It affects both vegetation and soil. It is also helpful in maintaining diversity and stability of ecosystems. Effect of forest fire and prescribed fire on forest soil is very complex. It affects soil organic matter, macro and micro-nutrients, physical properties of soil like texture, colour, pH, Bulk Density as well as soil biota. The impact of fire on forest soil depends on various factors such as intensity of fire, fuel load and...

  20. Analysis of Basis Weight Uniformity of Microfiber Nonwovens and Its Impact on Permeability and Filtration Properties

    Science.gov (United States)

    Amirnasr, Elham

    It is widely recognized that nonwoven basis weight non-uniformity affects various properties of nonwovens. However, few studies can be found in this topic. The development of uniformity definition and measurement methods and the study of their impact on various web properties such as filtration properties and air permeability would be beneficial both in industrial applications and in academia. They can be utilized as a quality control tool and would provide insights about nonwoven behaviors that cannot be solely explained by average values. Therefore, for quantifying nonwoven web basis weight uniformity we purse to develop an optical analytical tool. The quadrant method and clustering analysis was utilized in an image analysis scheme to help define "uniformity" and its spatial variation. Implementing the quadrant method in an image analysis system allows the establishment of a uniformity index that can be used to quantify the degree of uniformity. Clustering analysis has also been modified and verified using uniform and random simulated images with known parameters. Number of clusters and cluster properties such as cluster size, member and density was determined. We also utilized this new measurement method to evaluate uniformity of nonwovens produced with different processes and investigated impacts of uniformity on filtration and permeability. The results of quadrant method shows that uniformity index computed from quadrant method demonstrate a good range for non-uniformity of nonwoven webs. Clustering analysis is also been applied on reference nonwoven with known visual uniformity. From clustering analysis results, cluster size is promising to be used as uniformity parameter. It is been shown that non-uniform nonwovens has provide lager cluster size than uniform nonwovens. It was been tried to find a relationship between web properties and uniformity index (as a web characteristic). To achieve this, filtration properties, air permeability, solidity and

  1. The impact of welding wire on the mechanical properties of welded joints

    Directory of Open Access Journals (Sweden)

    Magdalena Mazur

    2014-06-01

    Full Text Available This paper presents results of the mechanical properties of Hardox 450 steel welded joints. These welded joints were made in accordance with welding procedure specifications (WPS, which was prepared and  applied in the Wielton company. Fillers were provided by welding wires with two different diameters. The welding wire was G4Sil with diameter of 1.0 mm and 1.2 mm. The aim of this study was to examine whether the thickness of the welding wire has a direct effect on the properties of welded joints. Test specimens were made in similar parameters of the welding process. Then they were subjected to macroscopic research, tensile strength, impact strength and hardness

  2. The impact of the manufacturing process on the hardness and sensory properties of milk chocolate

    Directory of Open Access Journals (Sweden)

    Zarić Danica B.

    2012-01-01

    Full Text Available The aim of this paper was to examine the impact of the manufacturing process on the textural characteristics and sensory properties of milk chocolate. The research was conducted on the samples of chocolate produced in a ball mill during 30, 60 and 90 minutes of refining, each of them being pre-crystallized at 26, 28 and 30°C. A chocolate mass of identical ingredient composition was also produced using a standard manufacturing process at the same pre-crystallization temperatures. Chocolate hardness was examined using a piece of equipment called Texture Analyser, measuring the stress intensity which leads to chocolate crushing. Sensory analysis was performed using the point scoring method. The new manufacturing process, i.e. the manufacturing of chocolate in a ball mill improves sensory properties and hardness of milk chocolate. [Projekat Ministarstva nauke Republike Srbije, br. TR 31014

  3. THE IMPACT OF RELATIVE HUMIDITY ON THE RADIATIVE PROPERTY AND RADIATIVE FORCING OF SULFATE AEROSOL

    Institute of Scientific and Technical Information of China (English)

    张立盛; 石广玉

    2001-01-01

    With the data of complex refractive index of sulfate aerosol, the radiative properties of the aerosol under 8 relative humidity conditions are calculated in this paper. By using the concentration distribution from two CTM models and LASG GOALS/AGCM, the radiative forcing due to hygroscopic sulfate aerosol is simulated. The results show that: (1) With the increase of relative humidity, the mass extinction coefficiency factor decreases in the shortwave spectrum: single scattering albedo keeps unchanged except for a little increase in longwave spectrum, and asymmetry factor increases in whole spectrum. (2) Larger differences occur in radiative forcing simulated by using two CTM data, and the global mean forcing is -0. 268 and -0. 816 W/m2,respectively. (3) When the impact of relative humidity on radiative property is taken into account,the distribution pattern of radiative forcing due to the wet particles is very similar to that of dry sulfate, but the forcing value decreases by 6%.

  4. The impact of relative humidity during electrospinning on the morphology and mechanical properties of nanofibers.

    Science.gov (United States)

    Pelipenko, Jan; Kristl, Julijana; Janković, Biljana; Baumgartner, Saša; Kocbek, Petra

    2013-11-01

    Electrospinning is an efficient and flexible method for nanofiber production, but it is influenced by many systemic, process, and environmental parameters that govern the electrospun product morphology. This study systematically investigates the influence of relative humidity (RH) on the electrospinning process. The results showed that the morphology of the electrospun product (shape and diameter) can be manipulated with precise regulation of RH during electrospinning. Because the diameter of nanofibers correlates with their rigidity, it was shown that RH control can lead to manipulation of material mechanical properties. Finally, based on the solution's rheological parameter-namely, phase shift angle-we were able to predict the loss of homogenous nanofiber structure in correlation with RH conditions during electrospinning. This research addresses the mechanism of RH impact on the electrospinning process and offers the background to exploit it in order to better control nanomaterial properties and alter its applicability.

  5. Mechanical properties of sisal fibre reinforced urea-formaldehyde resin composites

    Directory of Open Access Journals (Sweden)

    2007-10-01

    Full Text Available Alkali-treated sisal fibres were used as novel reinforcement to obtain composites with self-synthesized ureaformaldehyde resin as matrix phase. The composites were prepared by means of compression molding, and then the effects of sisal loading on mechanical properties such as impact strength, flexural strength, and wear resistance were investigated. In addition, water uptake was studied and structural features were revealed by the scanning electron microscopy (SEM. The composite with 30 wt% sisal fibres gives excellent flexural strength, water absorption, and especially the wear resistance showing that it has the most superior bonding and adhesion of all the composites. In particular, the highest value 9.42 kJ/m2 of charpy impact strength is observed in the composite with 50 wt% sisal fibre. SEM micrographs of impact fractured and worn surfaces clearly demonstrate the interfacial adhesion between fibre and matrix. This work shows the potential of sisal fibre (SF to improve the composite wear resistance and to be used in fibreboard.

  6. MECHANICAL AND THERMAL PROPERTIES OF NANOSIZED TITANIUM DIOXIDE FILLED RIGID POLY(VINYL CHLORIDE)

    Institute of Scientific and Technical Information of China (English)

    Yun-xiang Zhang; Yi-hu Song; Qiang Zheng

    2013-01-01

    Nano-sized rod-like titanium dioxide (TiO2) filled rigid poly(vinyl chloride) (PVC) nanocomposites were prepared by using injection-molding method.Vicat,Charpy impact and tensile tests as well as thermogravimetric and dynamic mechanical analyses were used to characterize the structure and properties of the nanocomposites.The results showed that nano-TiO2 could improve Vicar softening temperature and also improve thermal stability of PVC during the stages of dehydrochlorination and formation of carbonaceous conjugated polyene sequences,which can be ascribed to restriction of the nanoparticles on the segmental relaxation as being evidenced by raises in glass transition and β-relaxation temperatures of PVC upon filling TiO2.Addition of TiO2 nanoparticles less than 40 phr (parts per hundreds of resin) could significantly improve impact strength of the composites while the TiO2 agglomeration at high contents leads to a reduction in impact toughness.

  7. Physico-chemical properties and cytotoxic effects of sugar-based surfactants: Impact of structural variations.

    Science.gov (United States)

    Lu, Biao; Vayssade, Muriel; Miao, Yong; Chagnault, Vincent; Grand, Eric; Wadouachi, Anne; Postel, Denis; Drelich, Audrey; Egles, Christophe; Pezron, Isabelle

    2016-09-01

    Surfactants derived from the biorefinery process can present interesting surface-active properties, low cytotoxicity, high biocompatibility and biodegradability. They are therefore considered as potential sustainable substitutes to currently used petroleum-based surfactants. To better understand and anticipate their performances, structure-property relationships need to be carefully investigated. For this reason, we applied a multidisciplinary approach to systematically explore the effect of subtle structural variations on both physico-chemical properties and biological effects. Four sugar-based surfactants, each with an eight carbon alkyl chain bound to a glucose or maltose head group by an amide linkage, were synthesized and evaluated together along with two commercially available standard surfactants. Physico-chemical properties including solubility, Krafft point, surface-tension lowering and critical micellar concentration (CMC) in water and biological medium were explored. Cytotoxicity evaluation by measuring proliferation index and metabolic activity against dermal fibroblasts showed that all surfactants studied may induce cell death at low concentrations (below their CMC). Results revealed significant differences in both physico-chemical properties and cytotoxic effects depending on molecule structural features, such as the position of the linkage on the sugar head-group, or the orientation of the amide linkage. Furthermore, the cytotoxic response increased with the reduction of surfactant CMC. This study underscores the relevance of a methodical and multidisciplinary approach that enables the consideration of surfactant solution properties when applied to biological materials. Overall, our results will contribute to a better understanding of the concomitant impact of surfactant structure at physico-chemical and biological levels.

  8. Impact of carbonation on the durability of cementitious materials: water transport properties characterization

    Directory of Open Access Journals (Sweden)

    Le Bescop P.

    2013-07-01

    Full Text Available Within the context of long-lived intermediate level radioactive waste geological disposal, reinforced concrete would be used. In service life conditions, the concrete structures would be subjected to drying and carbonation. Carbonation relates to the reaction between carbon dioxide (CO2 and the main hydrates of the cement paste (portlandite and C-S-H. Beyond the fall of the pore solution pH, indicative of steel depassivation, carbonation induces mineralogical and microstructural changes (due to portlandite and C-S-H dissolution and calcium carbonate precipitation. This results in the modification of the transport properties, which can impact the structure durability. Because concrete durability depends on water transport, this study focuses on the influence of carbonation on water transport properties. In fact, the transport properties of sound materials are known but they still remain to be assessed for carbonated ones. An experimental program has been designed to investigate the transport properties in carbonated materials. Four hardened cement pastes, differing in mineralogy, are carbonated in an accelerated carbonation device (in controlled environmental conditions at CO2 partial pressure of about 3%. Once fully carbonated, all the data needed to describe water transport, using a simplified approach, will be evaluated.

  9. Subtask 12A2: Fabrication and properties of laboratory-scale heat of V-5Cr-5Ti

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-03-01

    The immediate objective of this work is to fabricate a new laboratory-scale heat of V-5Cr-5Ti and identify optimal annealing procedure that produces the highest impact toughness in the alloy. By comparing the result with the optimal annealing procedure identified for the production- and laboratory-scale heats of V-4Cr-4Ti, the eventual objective of the study is to demonstrate that excellent and reliable mechanical properties of V-(4-5)Cr-(4-5)Ti alloy class can be produced through a common annealing procedure. Impact properties were determined on a new 15-kg laboratory heat of V-5Cr-5Ti, fabricated by the same procedures as those used to produce the 500-kg production-scale heat of V-4Cr-4Ti, to identify optimal annealing procedure of the alloy. Charpy-impact tests were conducted on one-third-size specimens because low-temperature (<0{degrees}C) impact properties have been known to be most sensitive to the structure and quality of V-(4-5)Cr-(4-5)Ti alloy class. After final annealing at {approx}1000{degrees}C for 1 h in high-quality vacuum, the laboratory heat V-5Cr-5Ti exhibited impact properties as excellent as those of the production-scale heat V-4Cr-4Ti; i.e., DBTT < -200{degrees}C and absorbed energies of 10-16 J. This demonstrates that when annealed at common optimal condition of 1000{degrees}C for 1 h, the V-(4-5)Cr-(4-5)Ti alloy class exhibit excellent impact toughness and a sufficient tolerance to minor variations in alloying element composition. 5 refs., 5 figs., 1 tab.

  10. 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.

  11. Effect of austenitizing conditions on the impact properties of an alloyed austempered ductile iron of initially ferritic matrix structure

    Science.gov (United States)

    Delia, M.; Alaalam, M.; Grech, M.

    1998-04-01

    The effect of austenitizing conditions on the microstructure and impact properties of an austempered ductile iron (ADI) containing 1.6% Cu and 1.6% Ni as the main alloying elements was investigated. Impact tests were carried out on samples of initially ferritic matrix structure and which had been first austenitized at 850,900, 950, and 1000°C for 15 to 360 min and austempered at 360°C for 180 min. Results showed that the austenitizing temperature, Tγ, and time, tγ, have a significant effect on the impact properties of the alloy. This has been attributed to the influence of these variables on the carbon kinetics. The impact energy is generally high after short tγ, and it falls with further soaking. In samples austenitized at 850 and 900°C, these trends correspond to the gradual disappearance of the pro-eutectoid ferrite and the attainment of fully developed ausferritic structures. In initially ferritic structures, the carbon diffusion distances involved during austenitization are large compared to those in pearlitic structures. This explains the relatively long soaking periods required to attain fully ausferritic structures, which in spite of the lower impact energy values, have a better combination of mechanical properties. Microstructures of samples austenitized at 950 and 1000°C contain no pro-eutectoid ferrite. The impact properties of the former structures are independent of tγ, while those solution treated at 1000°C are generally low and show wide variation over the range of soaking time investigated. For fully ausferritic structures, impact properties fall with an increase in Tγ. This is particularly evident at 1000°C. As the Tγ increases, the amount of carbon dissolved in the original austenite increases. This slows down the rate of austenite transformation and results in coarser structures with lower mechanical properties. Optimum impact properties are obtained following austenitizing between 900 and 950°C for 120 to 180 min.

  12. Effect of bainite transformation and retained austenite on mechanical properties of austempered spheroidal graphite cast steel

    Science.gov (United States)

    Takahashi, Toshio; Abe, Toshihiko; Tada, Shuji

    1996-06-01

    Austempered ductile iron (ADI) has excellent mechanical properties, but its Young's modulus is low. Austempered spheroidal graphite cast steel (AGS) has been developed in order to obtain a new material with superior mechanical properties to ADI. Its carbon content (approximately 1.0 pct) is almost one-third that of a standard ADI; thus, the volume of graphite is also less. Young's modulus of AGS is 195 to 200 GPa and is comparable to that of steel. Austempered spheroidal graphite cast steel has an approximately 200 MPa higher tensile strength than ADI and twice the Charpy absorbed energy of ADI. The impact properties and the elongation are enhanced with increasing volume fraction of carbon-enriched retained austenite. At the austempering temperature of 650 K, the volume fraction of austenite is approximately 40 pct for 120 minutes in the 2.4 pct Si alloy, although it decreases rapidly in the 1.4 pct Si alloy. The X-ray diffraction analysis shows that appropriate quantity of silicon retards the decomposition of the carbon-enriched retained austenite. For austempering at 570 K, the amount of the carbon-enriched austenite decreases and the ferrite is supersaturated with carbon, resulting in high tensile strength but low toughness.

  13. Effect of bainite transformation and retained austenite on mechanical properties of austempered spheroidal graphite cast steel

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Toshio; Abe, Toshihiko; Tada, Shuji [Tohoku National Industrial Research Inst., Sendai (Japan). Materials Engineering Div.

    1996-06-01

    Austempered ductile iron (ADI) has excellent mechanical properties, but its Young`s modulus is low. Austempered spheroidal graphite cast steel (AGS) has been developed in order to obtain a new material with superior mechanical properties to ADI. Its carbon content (approximately 1.0 pct) is almost one-third that of a standard ADI; thus, the volume of graphite is also less. Young`s modulus of AGS is 195 to 200 GPa and is comparable to that of steel. Austempered spheroidal graphite cast steel has an approximately 200 MPa higher tensile strength than ADI and twice the Charpy absorbed energy of ADI. The impact properties and the elongation are enhanced with increasing volume fraction of carbon-enriched retained austenite. At the austempering temperature of 650 K, the volume fraction of austenite is approximately 40 pct for 120 minutes in the 2.4 pct Si alloy, although it decreases rapidly in the 1.4 pct Si alloy. The X-ray diffraction analysis shows that appropriate quantity of silicon retards the decomposition of the carbon-enriched retained austenite. For austempering at 570 K, the amount of the carbon-enriched austenite decreases and the ferrite is supersaturated with carbon, resulting in high tensile strength but low toughness.

  14. Economic impacts of land development: employment, housing, and property values. [Monograph

    Energy Technology Data Exchange (ETDEWEB)

    Muller, T.

    1976-01-01

    This report examines the effects of land development on three areas of the economy: employment, housing, and wealth. The main objective is to provide local governments with inexpensive methods for estimating the impact of new development on demand for employment and housing. Since both employment and housing effects are regional in nature, regional impacts are also noted. National patterns are shown to provide a basis of comparison between local data and national directions. Most changes in property value tend to occur at the neighborhood level. This is one reason for the comparatively limited interest in this subject at the community or regional level. The three areas examined in this study--employment, housing, and wealth--are viewed as one unit for analysis, since each interacts with the others. Additional employment resulting from industrial, commercial, or other development increases the demand for housing. In turn, changes in housing demand affect the value of the existing housing stock and developable land. Residential construction increases the supply of housing and thus affects both the price of existing dwelling units and potentially the level of inmigration to a community due to expanding employment opportunities. And higher per capita personal income resulting from expanded employment opportunities increases demand for housing. (Although income is not treated separately in this report, its relationship to employment, housing demand, and property value is noted.)

  15. Effects of Various Heat Treatments on the Ballistic Impact Properties of Inconel 718 Investigated

    Science.gov (United States)

    Pereira, J. Michael; Lerch, Bradley A.

    2000-01-01

    Uncontained failures of aircraft engine fan blades are serious events that can cause equipment damage and loss of life. Federal Aviation Administration (FAA) certification requires that all engines demonstrate the ability to contain a released fan blade with the engine running at full power. However, increased protection generally comes at the expense of weight. Proper choice of materials is therefore imperative to an optimized design. The process of choosing a good casing material is done primarily through trial and error. This costly procedure could be minimized if there was a better understanding of the relationships among static material properties, impact properties, and failure mechanisms. This work is part of a program being conducted at the NASA Glenn Research Center at Lewis Field to study these relationships. Ballistic impact tests were conducted on flat, square sheets of Inconel 718 that had been subjected to different heat treatments. Two heat treatments and the as-received condition were studied. In addition, results were compared with those from an earlier study involving a fourth heat treatment. The heat treatments were selected on the basis of their effects on the static tensile properties of the material. The impact specimens used in this study were 17.8-cm square panels that were centered and clamped over a 15.2-cm square hole in a 1.27-cm-thick steel plate. Three nominal plate thickness dimensions were studied, 1.0, 1.8, and 2.0 mm. For each thickness, all the specimens were taken from the same sheet of material. The projectile was a Ti-6Al-4V cylinder with a length of 25.4 mm, a diameter of 12.7 mm, and a mass ranging from 14.05 to 14.20 g. The projectiles were accelerated toward the specimens at normal incidence using a gas gun with a 2-m-long, 12.7-mm inner-diameter barrel. The ballistic limit for each heat treatment condition and thickness was determined by conducting a number of impact tests that bracketed as closely as possible the velocity

  16. Impact of neutrino properties on the estimation of inflationary parameters from current and future observations

    Science.gov (United States)

    Gerbino, Martina; Freese, Katherine; Vagnozzi, Sunny; Lattanzi, Massimiliano; Mena, Olga; Giusarma, Elena; Ho, Shirley

    2017-02-01

    We study the impact of assumptions about neutrino properties on the estimation of inflationary parameters from cosmological data, with a specific focus on the allowed contours in the ns/r plane, where ns is the scalar spectral index and r is the tensor-to-scalar ratio. We study the following neutrino properties: (i) the total neutrino mass Mν=∑i mi (where the index i =1 , 2, 3 runs over the three neutrino mass eigenstates); (ii) the number of relativistic degrees of freedom Neff at the time of recombination; and (iii) the neutrino hierarchy. Whereas previous literature assumed three degenerate neutrino masses or two massless neutrino species (approximations that clearly do not match neutrino oscillation data), we study the cases of normal and inverted hierarchy. Our basic result is that these three neutrino properties induce measurements are included, the standard contours in the ns/r plane are basically reproduced. Larger shifts of the contours in the ns/r plane (up to 0.8 σ ) arise for nonstandard values of Neff. We also provide forecasts for the future CMB experiments Cosmic Origins Explorer (COrE, satellite) and Stage-IV (ground-based) and show that the incomplete knowledge of neutrino properties, taken into account by a marginalization over Mν, could induce a shift of ˜0.4 σ toward lower values in the determination of ns (or a ˜0.8 σ shift if one marginalizes over Neff). Comparison to specific inflationary models is shown. Imperfect knowledge of neutrino properties must be taken into account properly, given the desired precision in determining whether or not inflationary models match the future data.

  17. Impact of dilution on the microstructure and properties of Ni-based 625 alloy coatings

    Directory of Open Access Journals (Sweden)

    Tiago Jose Antoszczyszyn

    2014-06-01

    Full Text Available Nickel-based alloy IN 625 is used to protect components of aircrafts, power generation and oil refinery due to an association of toughness and high corrosion resistance. These properties are associated with the chemical composition and microstructure of coatings which depend on the processing parameters and the composition of the component being protected. This paper assessed impact of dilution on the microstructure and properties of the Ni alloy IN 625 deposited by Plasma Transferred Arc (PTA on two substrates: carbon steel API 5L and stainless steel AISI 316L. Differences due to the interaction with the substrate were maximized analyzing single layer coatings, processed with three deposition current: 120, 150 and 180 A. Correlation with a cast Nickel-based alloy sample contributed to assess the impact of dilution on coatings. Dilution was determined by the area ratio and Vickers hardness measured on the transverse section of coatings. Scanning electron and Laser confocal microscopy and X-ray diffraction analysis were carried out to characterize the microstructure. Results indicated the increasing dilution with the deposition current was deeply influenced by the substrate. Dilution ranging from 5 to 29% was measured on coatings processed on the API 5L steel and from 22 to 51% on the low thermal conductivity AISI 316L steel substrate. Differences on the microstructure and properties of coatings can be associated with the interaction with each substrate. Higher fraction of carbides account for the higher coating hardness when processing on API 5L whereas the low thermal conductivity of AISI 316L and the higher Fe content in solid solution contributed to the lower hardness of coatings.

  18. Impact of phytic acid on nutrient bioaccessibility and antioxidant properties of dehusked rice.

    Science.gov (United States)

    Lee, H H; Loh, S P; Bong, C F J; Sarbini, S R; Yiu, P H

    2015-12-01

    Whole grains consumption promotes health benefits, but demonstrates controversial impacts from phytic acid in meeting requirements of good health. Therefore, this study was aimed to determine the nutrient bioaccessibility and antioxidant properties of rice cultivars named "Adan" or "Bario" and deduce the nutritional impact of phytic acid. Majority of the dehusked rice in the collection showed an acceptable level of in-vitro starch digestibility and in-vitro protein digestibility, but were poor in antioxidant properties and bioaccessibility of minerals (Ca, Fe and Zn). The drawbacks identified in the rice cultivars were due to relatively high phytic acid content (2420.6 ± 94.6 mg/100 g) and low phenolic content (152.39 ± 18.84 μg GAE/g). The relationship between phytic acid content and mineral bioaccessibility was strongest in calcium (r = 0.60), followed by iron (r = 0.40) and zinc (r = 0.27). Phytic acid content did not significantly correlate with in-vitro starch digestibility and in-vitro protein digestibility but showed a weak relationship with antioxidant properties. These suggest that phytic acid could significantly impair the mineral bioaccessibility of dehusked rice, and also act as an important antioxidant in non-pigmented rice. Bario rice cultivars offered dehusked rice with wide range of in-vitro digestibility of starch and protein, and also pigmented rice as a good source of antioxidants. However, there is a need to reduce phytic acid content in dehusked rice for improved mineral bioaccessibility among Bario rice cultivars.

  19. 重组竹的耐冲击性能%Impact Resistance Properties of Bamboo Scrimber

    Institute of Scientific and Technical Information of China (English)

    于子绚; 江泽慧; 王戈; 程海涛; 张文福; 邱亚新

    2012-01-01

    Low-velocity impact tests were conducted on bamboo scrimber and bamboo-wood scrimber by Instron Dynatup 9 250 HV drop weight impact testing machines in order to explore the adaptabilities of bamboo-wood composites under impact load in extreme circumstances (hurricane or hail storm) and provide a basis for reasonable structural design. The impact properties and damage mechanisms of the two kinds of materials were investigated. Results show that the impact properties of the bamboo scrimber with high density are better compared with that with low density, while the bamboo-wood serimber with vertical and horizontal structure is prior to the bamboo scrimber at the same density level. The impact damage results in longitudinal crack along the fiber direction which leads to overall failure of the material. However, the bamboo-wood scrimber with vertical and horizontal structure could restrain the crack propagation, and defects only occur near the impact position, in which the exit plane of the hammer presents a layered cracking, indicating a layered energy absorbing mechanism. The bamboo-wood scrimber with the same density exhibits a strong ability to resist impact damage.%探索竹/木复合材料在极端环境中(飓风、雹暴等)对冲击载荷的适应性,并在此基础上进行合理的结构设计.利用Instron 9250HV落锤冲击试验机对毛竹重组竹和竹木复合重组材进行了低速冲击试验,研究了密度和组坯形式对冲击性能和损伤模式的影响,并分析了组坯结构与吸能机制的关系.结果表明:高密度重组竹的耐冲击性能较好,纵横组坯的竹木复合重组材冲击性能优于同密度的重组竹.冲击损伤使重组竹沿纤维方向纵向开裂,导致材料整体失效;而竹木复合重组材的横纵结构抑制了裂纹的扩展,使缺陷仅发生在冲击点附近;落锤出射面表现为层状开裂,具有分层吸能的能量吸收机制.相同密度的竹木复合重组材可以更好地抵抗冲击破坏.

  20. The impact of substrate properties and thermal annealing on tantalum nitride thin films

    Science.gov (United States)

    Grosser, M.; Münch, M.; Seidel, H.; Bienert, C.; Roosen, A.; Schmid, U.

    2012-01-01

    In this study film properties of sputter-deposited tantalum nitride (TaNx) thin layers are investigated focusing on the impact of substrate properties, varying nitrogen content for film synthetization as well as post-deposition annealings in the temperature range up to 500 °C. For comparison, these investigations are done on low temperature co-fired ceramics and on silicon based substrates whereas the latter approach ensures defined and well-known surface properties. Furthermore, results on the phase evolution with high temperature annealings are presented showing a transformation of Ta4N to Ta2N in the temperature range between 350 °C and 500 °C. With increasing nitrogen content (i.e. nitrogen flow during film deposition) in the TaNx layers the topography shows first an increase in surface roughness, next a range where a smoothing of the surface characteristics is observed, and finally buckling and the existence of grain agglomerates. All these analyses are further evaluated with electrical measurements on the film resistivity and on the oxidation behaviour to gain deeper insight into material parameters relevant for micromachined devices which are operated under harsh environmental conditions.

  1. The impact of substrate properties and thermal annealing on tantalum nitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Grosser, M., E-mail: michaela_grosser@yahoo.de [Chair of Micromechanics, Microfluidics/Microactuators, Saarland University, 66123 Saarbruecken (Germany); Muench, M.; Seidel, H. [Chair of Micromechanics, Microfluidics/Microactuators, Saarland University, 66123 Saarbruecken (Germany); Bienert, C.; Roosen, A. [Friedrich-Alexander-University Erlangen-Nuremberg, Martensstr. 5, D-91058 Erlangen (Germany); Schmid, U. [Department for Microsystems Technology, Institute of Sensor and Actuator Systems, Vienna University of Technology, Floragasse 7, 1040 Vienna (Austria)

    2012-01-15

    In this study film properties of sputter-deposited tantalum nitride (TaN{sub x}) thin layers are investigated focusing on the impact of substrate properties, varying nitrogen content for film synthetization as well as post-deposition annealings in the temperature range up to 500 Degree-Sign C. For comparison, these investigations are done on low temperature co-fired ceramics and on silicon based substrates whereas the latter approach ensures defined and well-known surface properties. Furthermore, results on the phase evolution with high temperature annealings are presented showing a transformation of Ta{sub 4}N to Ta{sub 2}N in the temperature range between 350 Degree-Sign C and 500 Degree-Sign C. With increasing nitrogen content (i.e. nitrogen flow during film deposition) in the TaN{sub x} layers the topography shows first an increase in surface roughness, next a range where a smoothing of the surface characteristics is observed, and finally buckling and the existence of grain agglomerates. All these analyses are further evaluated with electrical measurements on the film resistivity and on the oxidation behaviour to gain deeper insight into material parameters relevant for micromachined devices which are operated under harsh environmental conditions.

  2. Impact of forest fire on physical, chemical and biological properties of soil: A review

    Directory of Open Access Journals (Sweden)

    Satyam Verma

    2012-09-01

    Full Text Available Forest fire is very common to all the ecosystems of the world. It affects both vegetation and soil. It is also helpful in maintaining diversity and stability of ecosystems. Effect of forest fire and prescribed fire on forest soil is very complex. It affects soil organic matter, macro and micro-nutrients, physical properties of soil like texture, colour, pH, Bulk Density as well as soil biota. The impact of fire on forest soil depends on various factors such as intensity of fire, fuel load and soil moisture. Fire is beneficial as well as harmful for the forest soil depending on its severity and fire return interval. In low intensity fires, combustion of litter and soil organic matter increase plant available nutrients, which results in rapid growth of herbaceous plants and a significant increase in plant storage of nutrients. Whereas high intensity fires can result into complete loss of soil organic matter, volatilization of N, P, S, K, death of microbes, etc. Intense forest fire results into formation of some organic compounds with hydrophobic properties, which results into high water repellent soils. Forest fire also causes long term effect on forest soil. The purpose of this paper is to review the effect of forest fire on various properties of soil, which are important in maintaining healthy ecosystem.

  3. Dynamic performance of a static or throwing droplet impact onto a solid substrate with different properties

    Science.gov (United States)

    Wu, Jie; Li, Ya-Dong

    2016-03-01

    The dynamic performance of a static or throwing droplet impact onto a solid substrate with different properties is numerically studied in this work. After being released or horizontally thrown out, a two-dimensional droplet can fall freely under gravity. The substrate, which is below the droplet, is either hydrophilic/hydrophobic or inhomogeneous. To conduct numerical simulations, a hybrid method is adopted, in which the flow field is solved by using the lattice Boltzmann method and the interface is captured by solving the Cahn-Hilliard equation directly. Given a fixed distance between the droplet and the substrate (H∗), the effects of Bond number (Bo), Weber number (We), and surface property on the performance of droplet impingement are investigated in detail. With the increase of Bond number, the surface coverage area of a static droplet also increases. A hydrophilic surface or an inhomogeneous surface with small advancing/receding angle difference can lead to the breakup of droplet rim due to the bubble entrapment. Moreover, dependent on the Weber number and the surface property, the leading edge rim of a throwing droplet developing on an inhomogeneous surface may break up before or after it contacts the substrate. As a result, compared to the case of static droplet, the surface coverage area will be reduced due to the diffusion of small droplet segment.

  4. Spectral properties of simulated impact glasses produced from martian soil analogue JSC Mars-1

    Science.gov (United States)

    Moroz, L. V.; Basilevsky, A. T.; Hiroi, T.; Rout, S. S.; Baither, D.; van der Bogert, C. H.; Yakovlev, O. I.; Fisenko, A. V.; Semjonova, L. F.; Rusakov, V. S.; Khramov, D. A.; Zinovieva, N. G.; Arnold, G.; Pieters, C. M.

    2009-07-01

    To simulate the formation of impact glasses on Mars, an analogue of martian bright soil (altered volcanic soil JSC Mars-1) was melted at relevant oxygen fugacities using a pulsed laser and a resistance furnace. Reduction of Fe3+ to Fe2+ and in some cases formation of nanophase Fe0 in the glasses were documented by Mössbauer spectroscopy and TEM studies. Reflectance spectra for several size fractions of the JSC Mars-1 sample and the glasses were acquired between 0.3 and 25 μm. The glasses produced from the JSC Mars-1 soil show significant spectral variability depending on the method of production and the cooling rate. In general, they are dark and less red in the visible compared to the original JSC Mars-1 soil. Their spectra do not have absorption bands due to bound water and structural OH, have positive spectral slopes in the near-infrared range, and show two broad bands centered near 1.05 and 1.9 μm, typical of glasses rich in ferrous iron. The latter bands and low albedo partly mimic the spectral properties of martian dark regions, and may easily be confused with mafic materials containing olivine and low-Ca pyroxene. Due to their disordered structures and vesicular textures, the glasses show relatively weak absorption features from the visible to the thermal infrared. These weak absorption bands may be masked by the stronger bands of mafic minerals. Positive near-infrared spectral slopes typical of fresh iron-bearing impact or volcanic glasses may be masked either by oxide/dust coatings or by aerosols in the Mars' atmosphere. As a result, impact glasses may be present on the surface of Mars in significant quantities that have been either misidentified as other phases or masked by phases with stronger infrared features. Spectrometers with sufficient spatial resolution and wavelength coverage may detect impact glasses at certain locations, e.g., in the vicinity of fresh impact craters. Such dark materials are usually interpreted as accumulations of mafic

  5. The effect of the accelerated aging on the mechanical properties of the PMMA denture base materials modified with itaconates

    Directory of Open Access Journals (Sweden)

    Spasojević Pavle M.

    2011-01-01

    Full Text Available This study evaluated the effect of accelerated ageing on the tensile strength, elongation at break, hardness and Charpy impact strength in commercial PMMA denture base material modified with di-methyl itaconate (DMI and di-n-butyl itaconate (DBI. The samples were prepared by modifying commercial formulation by addition of itaconates in the amounts of 2.5, 5, 7.5 and 10% by weight. After polymerization samples were characterized by FT-IR and DSC analysis while residual monomer content was determined by HPLC-UV. Accelerated ageing was performed at 70°C in water for periods of 7, 15 and 30 days. Tensile measurements were performed using Instron testing machine while the hardness of the polymerized samples was measured by Shore D method. The addition of itaconate significantly reduces the residual MMA. Even at the small amounts of added itaconates (2.5% the residual MMA content was reduced by 50%. The increase of itaconate content in the system leads to the decrease of residual MMA. It has been found that the addition of di-n-alkyl itaconates decreases the tensile strength, hardness and Charpy impact strength and increases elongation at break. Samples modified with DMI had higher values of tensile strength, hardness and Charpy impact strength compared to the ones modified with DBI. This is explained by the fact that DBI has longer side chain compared to DMI. After accelerated ageing during a 30 days period the tensile strength decreased for all the investigated samples. The addition of DMI had no effect on the material ageing and the values for the tensile strength of all of the investigated samples decreased around 20%, while for the samples modified with DBI, the increase of the amount of DBI in the polymerized material leads to the higher decrease of the tensile strength after the complete accelerated ageing period od 30 days, aulthough after the first seven days of the accelerated ageing the values of hardness have increased for all of the

  6. Comparison of microstructure and mechanical properties of ultra-narrow gap laser and gas-metal-arc welded S960 high strength steel

    Science.gov (United States)

    Guo, Wei; Li, Lin; Dong, Shiyun; Crowther, Dave; Thompson, Alan

    2017-04-01

    The microstructural characteristics and mechanical properties, including micro-hardness, tensile properties, three-point bending properties and Charpy impact toughness at different test temperatures of 8 mm thick S960 high strength steel plates were investigated following their joining by multi-pass ultra-narrow gap laser welding (NGLW) and gas metal arc welding (GMAW) techniques. It was found that the microstructure in the fusion zone (FZ) for the ultra-NGLW joint was predominantly martensite mixed with some tempered martensite, while the FZ for the GMAW joint was mainly consisted of ferrite with some martensite. The strength of the ultra-NGLW specimens was comparable to that of the base material (BM), with all welded specimens failed in the BM in the tensile tests. The tensile strength of the GMAW specimens was reduced approximately by 100 MPa when compared with the base material by a broad and soft heat affected zone (HAZ) with failure located in the soft HAZ. Both the ultra-NGLW and GMAW specimens performed well in three-point bending tests. The GMAW joints exhibited better impact toughness than the ultra-NGLW joints.

  7. Impact of visual repetition rate on intrinsic properties of low frequency fluctuations in the visual network.

    Directory of Open Access Journals (Sweden)

    Yi-Chia Li

    Full Text Available BACKGROUND: Visual processing network is one of the functional networks which have been reliably identified to consistently exist in human resting brains. In our work, we focused on this network and investigated the intrinsic properties of low frequency (0.01-0.08 Hz fluctuations (LFFs during changes of visual stimuli. There were two main questions to be discussed in this study: intrinsic properties of LFFs regarding (1 interactions between visual stimuli and resting-state; (2 impact of repetition rate of visual stimuli. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed scanning sessions that contained rest and visual stimuli in various repetition rates with a novel method. The method included three numerical approaches involving ICA (Independent Component Analyses, fALFF (fractional Amplitude of Low Frequency Fluctuation, and Coherence, to respectively investigate the modulations of visual network pattern, low frequency fluctuation power, and interregional functional connectivity during changes of visual stimuli. We discovered when resting-state was replaced by visual stimuli, more areas were involved in visual processing, and both stronger low frequency fluctuations and higher interregional functional connectivity occurred in visual network. With changes of visual repetition rate, the number of areas which were involved in visual processing, low frequency fluctuation power, and interregional functional connectivity in this network were also modulated. CONCLUSIONS/SIGNIFICANCE: To combine the results of prior literatures and our discoveries, intrinsic properties of LFFs in visual network are altered not only by modulations of endogenous factors (eye-open or eye-closed condition; alcohol administration and disordered behaviors (early blind, but also exogenous sensory stimuli (visual stimuli with various repetition rates. It demonstrates that the intrinsic properties of LFFs are valuable to represent physiological states of human brains.

  8. Impacts of gantry angle dependent scanning beam properties on proton PBS treatment

    Science.gov (United States)

    Lin, Yuting; Clasie, Benjamin; Lu, Hsiao-Ming; Flanz, Jacob; Shen, Tim; Jee, Kyung-Wook

    2017-01-01

    While proton beam models in treatment planning systems are generally assumed invariant with respect to the beam deliveries at different gantry angles. Physical properties of scanning pencil beams can change. The gantry angle dependent properties include the delivered charge to the monitor unit chamber, the spot position and the spot shape. The aim of this study is to investigate the extent of the changes and their dosimetric impacts using historical pencil beam scanning (PBS) treatment data. Online beam delivery records at the time of the patient-specific qualify assurance were retrospectively collected for a total of 34 PBS fields from 28 patients treated at our institution. For each field, proton beam properties at two different gantry angles (the planned and zero gantry angles) were extracted by a newly-developed machine log analysis method and used to reconstruct the delivered dose distributions in the cubic water phantom geometry. The reconstructed doses at the two different angles and a planar dose measurement by a 2D ion-chamber array were compared and the dosimetric impacts of the gantry angle dependency were accessed by a 3D γ-index analysis. In addition, the pencil beam spot size was independently characterized as a function of the gantry angle and the beam energy. The dosimetric effects of the perturbed beam shape were also investigated. Comparisons of spot-by-spot beam positions between both gantry angles show a mean deviation of 0.4 and 0.7 mm and a standard deviation of 0.3 and 0.6 mm for x and y directions, respectively. The delivered giga-protons per spot show a percent mean difference and a standard deviation of 0.01% and 0.3%, respectively, from each planned spot weight. These small deviations lead to an excellent agreement in dose comparisons with an average γ passing rate of 99.1%. When each calculation for both planned and zero gantry angles was compared to the measurement, a high correlation in γ values was also observed, also

  9. Impacts of gantry angle dependent scanning beam properties on proton PBS treatment.

    Science.gov (United States)

    Lin, Yuting; Clasie, Benjamin; Lu, Hsiao-Ming; Flanz, Jacob; Shen, Tim; Jee, Kyung-Wook

    2017-01-21

    While proton beam models in treatment planning systems are generally assumed invariant with respect to the beam deliveries at different gantry angles. Physical properties of scanning pencil beams can change. The gantry angle dependent properties include the delivered charge to the monitor unit chamber, the spot position and the spot shape. The aim of this study is to investigate the extent of the changes and their dosimetric impacts using historical pencil beam scanning (PBS) treatment data. Online beam delivery records at the time of the patient-specific qualify assurance were retrospectively collected for a total of 34 PBS fields from 28 patients treated at our institution. For each field, proton beam properties at two different gantry angles (the planned and zero gantry angles) were extracted by a newly-developed machine log analysis method and used to reconstruct the delivered dose distributions in the cubic water phantom geometry. The reconstructed doses at the two different angles and a planar dose measurement by a 2D ion-chamber array were compared and the dosimetric impacts of the gantry angle dependency were accessed by a 3D γ-index analysis. In addition, the pencil beam spot size was independently characterized as a function of the gantry angle and the beam energy. The dosimetric effects of the perturbed beam shape were also investigated. Comparisons of spot-by-spot beam positions between both gantry angles show a mean deviation of 0.4 and 0.7 mm and a standard deviation of 0.3 and 0.6 mm for x and y directions, respectively. The delivered giga-protons per spot show a percent mean difference and a standard deviation of 0.01% and 0.3%, respectively, from each planned spot weight. These small deviations lead to an excellent agreement in dose comparisons with an average γ passing rate of 99.1%. When each calculation for both planned and zero gantry angles was compared to the measurement, a high correlation in γ values was also observed, also

  10. Thermal Properties of Starch From New Corn Lines as Impacted by Environment and During Line Development

    Energy Technology Data Exchange (ETDEWEB)

    Elizabeth M. Lenihan

    2003-12-12

    The objectives of this research were to further characterize exotic by adapted corn inbreds by studying the impact of environment on their starch thermal properties, and investigating the development of starch thermal properties during kernel maturation by using differential scanning calorimetry (DSC). A method to expedite identification of unusual starch thermal traits was investigated by examining five corn kernels at a time, instead of one kernel, which the previous screening methods used. Corn lines with known thermal functions were blended with background starch (control) in ratios of unique starch to control starch, and analyzed by using DSC. Control starch was representative of typical corn starch. The values for each ratio within a mutant type were unique ({alpha} < 0.01) for most DSC measurements. These results supported the five-kernel method for rapidly screening large amounts of corn germplasm to identify unusual starch traits. The effects of 5 growing locations on starch thermal properties from exotic by adapted corn and Corn Belt lines were studied using DSC. The warmest location, Missouri, generally produced starch with greater gelatinization onset temperature (T{sub oG}), narrower range of gelatinization (R{sub G}), and greater enthalpy of gelatinization ({Delta}H{sub G}). The coolest location, Illinois, generally resulted in starch with lower T{sub oG}, wider R{sub G}, and lower {Delta}H{sub G}. Starch from the Ames 1 farm had thermal properties similar to those of Illinois, whereas starch from the Ames 2 farm had thermal properties similar to those of Missouri. The temperature at Ames 2 may have been warmer since it was located near a river; however, soil type and quality also were different. Final corn starch structure and function change during development and maturity. Thus, the changes in starch thermal properties during 5 stages of endosperm development from exotic by adapted corn and Corn Belt lines at two locations were studied by using DSC

  11. Nanofilled and/or toughened POM composites produced by water-mediated melt compounding: Structure and mechanical properties

    Directory of Open Access Journals (Sweden)

    2008-10-01

    Full Text Available Binary and ternary composites composed of polyoxymethylene (POM, polyurethane (PU and synthetic boehmite alumina (AlO(OH were produced by water-mediated melt compounding technique. PU latex and/or aqueous alumina suspension were injected into the molten POM in a twin-screw extruder to prepare toughened and/or reinforced polymer composites. The dispersion of the alumina and PU was studied by transmission- and scanning electron microcopy techniques (TEM and SEM, respectively, and discussed. The crystallization of the POM-based systems was inspected by polarized optical microscopy (PLM. The mechanical and thermomechanical properties of the composites were determined in dynamic-mechanical thermal analysis (DMTA, short-time creep tests (performed at various temperatures, uniaxial static tensile and notched Charpy impact tests. Incorporation of alumina increased the stiffness and resistance to creep and reduced the tensile strength, elongation at break and impact toughness. The change in the above parameters was opposite for the POM/PU binary blends. Additional incorporation of alumina in the POM/PU blend enhanced the resistance to creep, elongation at break and maintained the impact toughness compared to the POM/PU blend.

  12. Changes in the properties of solonetzic soil complexes in the dry steppe zone under anthropogenic impacts

    Science.gov (United States)

    Lyubimova, I. N.; Novikova, A. F.

    2016-05-01

    Long-term studies of changes in the properties of solonetzic soil complexes of the dry steppe zone under anthropogenic impacts (deep plowing, surface leveling, irrigation, and post-irrigation use) have been performed on the Privolzhskaya sand ridge and the Khvalyn and Ergeni plains. The natural morphology of solonetzic soils was strongly disturbed during their deep ameliorative plowing. At present, the soil cover consists of solonetzic agrozems (Sodic Protosalic Cambisols (Loamic, Aric, Protocalcic)), textural (clay-illuvial) calcareous agrozems (Eutric Cambisols (Loamic, Aric, Protocalcic)), agrosolonetzes (Endocalcaric Luvisols (Loamic, Aric, Cutanic, Protosodic), agrochestnut soils (Eutric Cambisols (Siltic, Aric)), and meadowchestnut soils (Haplic Kastanozems). No features attesting to the restoration of the initial profile of solonetzes have been found. The dynamics of soluble salts and exchangeable sodium differ in the agrosolonetzes and solonetzic agrozems. A rise in pH values takes place in the middle part of the soil profiles on the Khvalyn and Ergeni plains.

  13. New method of the polymeric material properties experimental investigation under powerful energy flux impact

    Science.gov (United States)

    Demidov, B. A.; Efremov, V. P.; Kalinin, Yu G.; Kazakov, E. D.; Metelkin, S. Yu; Petrov, V. A.; Potapenko, A. I.

    2015-11-01

    Investigation of the polymeric material properties under powerfull energy flux impact is relevant as for basic research (mathematical modeling of polymeric materials behavior in extreme conditions, testing the state equations), as for practical applications (for testing of protective coatings for space research and laboratory facilities). This paper presents the results of experimental studies of the interaction of polymeric materials with a relativistic electron beam produced by a high-current electron accelerator Calamary. Calamary facility provides a wide range of electron beam parameters: diameter 10-15 mm, the voltage on the diode up to 300 kV, the current through the diode up to 30 kA. New method of beam-target interaction area measurement was developed. The original method for the mechanical kick impulse measuring based on piezoelectric vibration sensor was presented. The dependence of the kick impulse from the power flux was obtained.

  14. The impact properties of laminated composites containing ultrahigh carbon (UHC) steels

    Science.gov (United States)

    Kum, D. W.; Oyama, T.; Wadsworth, J.; Sherby, O. D.

    AN ULTRAHIGH carbon (UHC) steel/mild steel laminated composite and a UHC steel/UHC steel laminate have been successfully manufactured by a roll-bonding procedure. Impact properties of these laminates, as well as of monolithic samples of the steels contained in these laminates, have been determined in the crackarrestor orientation over the temperature range 25 to -196°C. Both notched and unnotched samples of the laminated composite and laminate have been tested. Extremely low ductile-to-brittle temperatures of -140°C, and very high shelf energies (>325 J), have been found both for the laminated composites and the laminates. This remarkably good behavior is shown to be a result of notch blunting by delamination within the laminates.

  15. Impact of speciation on the electron charge transfer properties of nanodiamond drug carriers

    Science.gov (United States)

    Sun, Baichuan; Barnard, Amanda S.

    2016-07-01

    Unpassivated diamond nanoparticles (bucky-diamonds) exhibit a unique surface reconstruction involving graphitization of certain crystal facets, giving rise to hybrid core-shell particles containing both aromatic and aliphatic carbon. Considerable effort is directed toward eliminating the aromatic shell, but persistent graphitization of subsequent subsurface-layers makes perdurable purification a challenge. In this study we use some simple statistical methods, in combination with electronic structure simulations, to predict the impact of different fractions of aromatic and aliphatic carbon on the charge transfer properties of the ensembles of bucky-diamonds. By predicting quality factors for a variety of cases, we find that perfect purification is not necessary to preserve selectivity, and there is a clear motivation for purifying samples to improve the sensitivity of charge transfer reactions. This may prove useful in designing drug delivery systems where the release of (selected) drugs needs to be sensitive to specific conditions at the point of delivery.Unpassivated diamond nanoparticles (bucky-diamonds) exhibit a unique surface reconstruction involving graphitization of certain crystal facets, giving rise to hybrid core-shell particles containing both aromatic and aliphatic carbon. Considerable effort is directed toward eliminating the aromatic shell, but persistent graphitization of subsequent subsurface-layers makes perdurable purification a challenge. In this study we use some simple statistical methods, in combination with electronic structure simulations, to predict the impact of different fractions of aromatic and aliphatic carbon on the charge transfer properties of the ensembles of bucky-diamonds. By predicting quality factors for a variety of cases, we find that perfect purification is not necessary to preserve selectivity, and there is a clear motivation for purifying samples to improve the sensitivity of charge transfer reactions. This may prove

  16. Phase Stability and Stoichiometry in Thin Film Iron Pyrite: Impact on Electronic Transport Properties.

    Science.gov (United States)

    Zhang, Xin; Scott, Tom; Socha, Tyler; Nielsen, David; Manno, Michael; Johnson, Melissa; Yan, Yuqi; Losovyj, Yaroslav; Dowben, Peter; Aydil, Eray S; Leighton, Chris

    2015-07-01

    The use of pyrite FeS2 as an earth-abundant, low-cost, nontoxic thin film photovoltaic hinges on improved understanding and control of certain physical and chemical properties. Phase stability, phase purity, stoichiometry, and defects, are central in this respect, as they are frequently implicated in poor solar cell performance. Here, phase-pure polycrystalline pyrite FeS2 films, synthesized by ex situ sulfidation, are subject to systematic reduction by vacuum annealing (to 550 °C) to assess phase stability, stoichiometry evolution, and their impact on transport. Bulk probes reveal the onset of pyrrhotite (Fe(1-δ)S) around 400 °C, rapidly evolving into the majority phase by 425 °C. This is supported by X-ray photoelectron spectroscopy on (001) crystals, revealing surface Fe(1-δ)S formation as low as 160 °C, with rapid growth near 400 °C. The impact on transport is dramatic, with Fe(1-δ)S minority phases leading to a crossover from diffusive transport to hopping (due to conductive Fe(1-δ)S nanoregions in an FeS2 matrix), followed by metallicity when Fe(1-δ)S dominates. Notably, the crossover to hopping leads to an inversion of the sign, and a large decrease in magnitude of the Hall coefficient. By tracking resistivity, magnetotransport, magnetization, and structural/chemical parameters vs annealing, we provide a detailed picture of the evolution in properties with stoichiometry. A strong propensity for S-deficient minority phase formation is found, with no wide window where S vacancies control the FeS2 carrier density. These findings have important implications for FeS2 solar cell development, emphasizing the need for (a) nanoscale chemical homogeneity, and (b) caution in interpreting carrier types and densities.

  17. 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.

  18. Mechanical Properties of V-, Nb-, and Ti-bearing As-cast Microalloyed Steels

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The influence of microalloying additions on the mechanical properties of a low-carbon cast steel containing combinations of V, Nb, and Ti in the as-cast condition was evaluated. Tensile and hardness test results indicated that good combinations of strength and ductility could be achieved by V and Nb additions. While the yield strength and UTS (ultimate tensile strength) increased up to the range of 378-435 MPa and 579-596 MPa, respectively in the microalloyed heats, their total elongation ranged from 18% to 23%. The presence of Ti, however, led to some reduction in the strength. Microstructural studies including scanning electron microscopy (SEM) and optical microscopy revealed that coarse TiN particles were responsible for this behavior. The Charpy impact values of all compositions indicated that microalloying additions significantly decreased the impact energy and led to the dominance of cleavage facets on the fracture surfaces. It seems that the increase in the hardness of coarse ferrite grains due to the precipitation hardening is the main reason for brittle fracture.

  19. PROPERTIES OF CP: COEFFICIENT OF THERMAL EXPANSION, DECOMPOSITION KINETICS, AND REACTION TO SPARK, FRICTION AND IMPACT

    Energy Technology Data Exchange (ETDEWEB)

    Weese, R K; Burnham, A K

    2005-09-28

    The properties of pentaamine (5-cyano-2H-tetrazolato-N2) cobalt (III) perchlorate (CP), which was first synthesized in 1968, continues to be of interest for predicting behavior in handling, shipping, aging, and thermal cook-off situations. We report coefficient of thermal expansion (CTE) values over four specific temperature ranges, decomposition kinetics using linear and isothermal heating, and the reaction to three different types of stimuli: impact, spark, and friction. The CTE was measured using a Thermal Mechanical Analyzer (TMA) for samples that were uniaxially compressed at 10,000 psi and analyzed over a dynamic temperature range of -20 C to 70 C. Differential scanning calorimetry, DSC, was used to monitor CP decomposition at linear heating rates of 1-7 C min{sup -1} in perforated pans and of 0.1-1.0 C min{sup -1} in sealed pans. The kinetic triplet was calculated using the LLNL code Kinetics05, and predictions for 210 and 240 C are compared to isothermal thermogravimetric analysis (TGA) experiments. Values are also reported for spark, friction, and impact sensitivity.

  20. Impact of low molecular weight organic acids (LMWOAs) on biochar micropores and sorption properties for sulfamethoxazole.

    Science.gov (United States)

    Sun, Binbin; Lian, Fei; Bao, Qiongli; Liu, Zhongqi; Song, Zhengguo; Zhu, Lingyan

    2016-07-01

    The interaction between biochar (BC) and antibiotics with the presence of low molecular weight organic acids (LMWOAs) is largely unknown, although it is crucial for understanding the role of BC in reducing the bioavailability of antibiotics in rhizosphere. The impacts of two typical LMWOAs (citric and malic acids) on sorption of sulfamethoxazole (SMX) by crop-straw BCs produced at 300 °C (BCs300) and 600 °C (BCs600), respectively, were examined. The sorption of SMX on BCs increased more than 5 times with the concentration of LMWOAs increasing from 0 to 100 mmol/L, which was mainly attributed to the elevated microporosity of BCs (measured by CO2) after treated by LMWOAs. The pore development of BCs was mainly derived from the release of dissolved organic residues from BC by LMWOA washing. For H2O2-oxidized BCs, however, LMWOAs had little effect on SMX sorption by BCs300 but greatly increased that by BCs600, which can be explained by the distinct sorption mechanisms of SMX on BCs300 and BCs600. These results indicate that the impact of LMWOAs on SMX sorption is highly dependent on the properties of BCs and LMWOAs, as well as their interaction mechanisms.

  1. Statistical investigation and thermal properties for a 1-D impact system with dissipation

    Energy Technology Data Exchange (ETDEWEB)

    Díaz I, Gabriel, E-mail: gabriel.diaz.iturry@gmail.com; Livorati, André L.P., E-mail: livorati@rc.unesp.br; Leonel, Edson D., E-mail: edleonel@rc.unesp.br

    2016-05-06

    Highlights: • The dynamics of a 1-D dissipative impact system is studied. • Statistical properties for the average velocity, root mean square velocity and its deviation are characterized. • A thermodynamics formalism is developed as function of the statistical variable. • The formalism shows itself to be robust, and we can predict numerical values without doing numerical simulations. - Abstract: The behavior of the average velocity, its deviation and average squared velocity are characterized using three techniques for a 1-D dissipative impact system. The system – a particle, or an ensemble of non-interacting particles, moving in a constant gravitation field and colliding with a varying platform – is described by a nonlinear mapping. The average squared velocity allows to describe the temperature for an ensemble of particles as a function of the parameters using: (i) straightforward numerical simulations; (ii) analytically from the dynamical equations; (iii) using the probability distribution function. Comparing analytical and numerical results for the three techniques, one can check the robustness of the developed formalism, where we are able to estimate numerical values for the statistical variables, without doing extensive numerical simulations. Also, extension to other dynamical systems is immediate, including time dependent billiards.

  2. Impacts of air pollution exposure on the allergenic properties of Arizona cypress pollens

    Energy Technology Data Exchange (ETDEWEB)

    Shahali, Y; Pourpak, Z; Moin, M; Zare, A [Immunology, Asthma and Allergy Research Institute, Medical Sciences/ University of Tehran (Iran, Islamic Republic of); Majd, A, E-mail: youcef.shahali@espci.f [Department of Biology, Faculty of Sciences, Islamic Azad University, North Tehran Branch (Iran, Islamic Republic of)

    2009-02-01

    Epidemiological studies have demonstrated that urbanization and high levels of vehicle emissions correlated with the increasing trend of pollen-induced respiratory allergies. Numerous works have investigated the role of pollutants in the pathogenesis of respiratory diseases but impacts of anthropogenic pollution on pollen allergenic properties are still poorly understood. The objective of this survey was to evaluate impacts of the traffic-related pollution on the structure and allergenic protein content of Arizona cypress (Cupressus arizonica, CA) pollens, recognized as a rising cause of seasonal allergy in various regions worldwide. According to our results, traffic-related air pollution by its direct effects on the elemental composition of pollens considerably increased the fragility of the pollen exine, causing numerous cracks in its surface and facilitating pollen content liberation. Pollen grains were also covered by numerous submicronic orbicules which may act as effective vectors for pollen-released components into the lower regions of respiratory organs. On the other hand, this study provides us reliable explications about the low efficiency of standard commercial allergens in the diagnosis of the Arizona cypress pollen allergy in Tehran. Although traffic related pollution affects the allergenic components of CA pollens, the repercussions on the respiratory health of urban populations have yet to be clarified and need further investigations.

  3. Mechanical properties of TIG and EB weld joints of F82H

    Energy Technology Data Exchange (ETDEWEB)

    Hirose, Takanori, E-mail: hirose.takanori@jaea.go.jp; Sakasegawa, Hideo; Nakajima, Motoki; Tanigawa, Hiroyasu

    2015-10-15

    Highlights: • Narrow groove TIG minimized volume of F82H weld. • Mechanical properties of TIG and EB welds of F82H have been characterized. • Post weld heat treatment successfully moderate the toughness of weld metal without softening the base metal. - Abstract: This work investigates mechanical properties of weld joints of a reduced activation ferritic/martensitic steel, F82H and effects of post weld heat treatment on the welds. Vickers hardness, tensile and Charpy impact tests were conducted on F82H weld joints prepared using tungsten-inert-gas and electron beam after various heat treatments. Although narrow groove tungsten-inert-gas welding reduced volume of weld bead, significant embrittlement was observed in a heat affected zone transformed due to heat input. Post weld heat treatment above 993 K successfully moderated the brittle transformed region. The hardness of the brittle region strongly depends on the heat treatment temperature. Meanwhile, strength of base metal was slightly reduced by the treatment at temperature ranging from 993 to 1053 K. Moreover, softening due to double welding was observed only in the weld metal, but negligible in base metal.

  4. Impact of Packing and Processing Technique on Mechanical Properties of Acrylic Denture Base Materials

    Directory of Open Access Journals (Sweden)

    Touraj Nejatian

    2015-04-01

    Full Text Available The fracture resistance of polymethylmethacrylate (PMMA as the most popular denture base material is not satisfactory. Different factors can be involved in denture fracture. Among them, flexural fatigue and impact are the most common failure mechanisms of an acrylic denture base. It has been shown that there is a correlation between the static strength and fatigue life of composite resins. Therefore, the transverse strength of the denture base materials can be an important indicator of their service life. In order to improve the fracture resistance of PMMA, extensive studies have been carried out; however, only a few promising results were achieved, which are limited to some mechanical properties of PMMA at the cost of other properties. This study aimed at optimizing the packing and processing condition of heat-cured PMMA as a denture base resin in order to improve its biaxial flexural strength (BFS. The results showed that the plain type of resin with a powder/monomer ratio of 2.5:1 or less, packed conventionally and cured in a water bath for 2 h at 95 °C provides the highest BFS. Also, it was found that the performance of the dry heat processor is inconsistent with the number of flasks being loaded.

  5. Simulation of Tillage Systems Impact on Soil Biophysical Properties Using the SALUS Model

    Directory of Open Access Journals (Sweden)

    Luigi Sartori

    2011-02-01

    Full Text Available A sustainable land management has been defined as the management system that allows for production, while minimizing risk, maintaining quality of soil and water. Tillage systems can significantly decrease soil carbon storage and influence the soil environment of a crop. Crop growth models can be useful tools in evaluating the impact of different tillage systems on soil biophysical properties and on the growth and final yield of the crops. The objectives of this paper were i to illustrate the SALUS model and its tillage component; ii to evaluate the effects of different tillage systems on water infiltration and time to ponding, iii to simulate the effect of tillage systems on some soil biophysical properties. The SALUS (System Approach to Land Use Sustainability model is designed to simulate continuous crop, soil, water and nutrient conditions under different tillage and crop residues management strategies for multiple years. Predictions of changes in surface residue, bulk density, runoff, drainage and evaporation were consistent with expected behaviours of these parameters as described in the literature. The experiment to estimate the time to ponding curve under different tillage system confirmed the theory and showed the beneficial effects of the residue on soil surface with respect to water infiltration. It also showed that the no-tillage system is a more appropriate system to adopt in areas characterized by high intensity rainfall.

  6. The Impacts of Optical Properties on Radiative Forcing Due to Dust Aerosol

    Institute of Scientific and Technical Information of China (English)

    WANG Hong; SHI Guangyu; LI Shuyan; LI Wei; WANG Biao; HUANG Yanbin

    2006-01-01

    There are large uncertainties in the quantitative assessment of radiative effects due to atmospheric dust aerosol. The optical properties contribute much to those uncertainties. The authors perform several sensitivity experiments to estimate the impacts of optical characteristics on regional radiative forcing in this paper. The experiments involve in refractive indices, single scattering albedo, asymmetry factor and optical depth. An updated dataset of refractive indices representing East Asian dust and the one recommended by the World Meteorology Organization (WMO) are contrastively analyzed and used. A radiative transfer code for solar and thermal infrared radiation with detailed aerosol parameterization is employed. The strongest emphasis is on the refractive indices since other optical parameters strongly depend on it, and the authors found a strong sensitivity of radiative forcing on refractive indices. Studies show stronger scattering, weaker absorption and forward scattering of the East Asian dust particles at solar wavelengths, which leads to higher negative forcing, lower positive forcing and bigger net forcing at the top of the atmosphere (TOA) than that of the WMO dust model. It is also found that the TOA forcings resulting from these two dust models have opposite signs in certain regions, which implies the importance of accurate measurements of optical properties in the quantitative estimation of radiative forcing.

  7. Effect of thermal aging on microstructure and mechanical properties of China low-activation martensitic steel at 550 degrees C

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei; Liu, Shao Jun; Xu, Gang; Zhang, Baoren; Huang, Qun Ying [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei (China)

    2016-04-15

    The thermal aging effects on mechanical properties and microstructures in China low-activation martensitic steel have been tested by aging at 550 degrees C for 2,000 hours, 4,000 hours, and 10,000 hours. The microstructure was analyzed by scanning and transmission electron microscopy. The results showed that the grain size and martensitic lath increased by about 4 μm and 0.3 μm, respectively, after thermal exposure at 550 degrees C for 10,000 hours. MX type particles such as TaC precipitated on the matrix and Laves-phase was found on the martensitic lath boundary and grain boundary on aged specimens. The mechanical properties were investigated with tensile and Charpy impact tests. Tensile properties were not seriously affected by aging. Neither yield strength nor ultimate tensile strength changed significantly. However, the ductile-brittle transition temperature of China low-activation martensitic steel increased by 46 degrees C after aging for 10,000 hours due to precipitation and grain coarsening.

  8. Effect of Ti-containing inclusions on the nucleation of acicular ferrite and mechanical properties of multipass weld metals.

    Science.gov (United States)

    Fattahi, M; Nabhani, N; Hosseini, M; Arabian, N; Rahimi, E

    2013-02-01

    In the present study, the influence of Ti-containing inclusions on the development of acicular ferrite microstructure and mechanical properties in the multipass weld metals has been studied. Shielded metal arc weld deposits were prepared by varying titanium content in the range of 0.003-0.021%. The variation in the titanium content was obtained by the addition of different amounts of titanium oxide nanoparticles to the electrode coating. The dispersion of titanium oxide nanoparticles, composition of inclusions, microstructural analysis, tensile properties and Charpy impact toughness were evaluated. As the amount of Ti-containing inclusions in the weld metal was increased, the microstructure of the weld metal was changed from the grain boundary allotriomorphic ferrite structure to acicular ferrite with the intragranular nucleation of ferrite on the Ti-containing inclusions, and the mechanical properties were improved. This improvement is attributable to the increased percentage of acicular ferrite due to the uniform dispersion of Ti-containing inclusions and the pinning force of oxide nanoparticles against the growth of allotriomorphic ferrite and Widmanstätten ferrite from the austenite grain boundaries.

  9. Heat treatment of investment cast PH 13-8 Mo stainless steel: Part I. Mechanical properties and microstructure

    Science.gov (United States)

    Hochanadel, P. W.; Edwards, G. R.; Robino, C. V.; Cieslak, M. J.

    1994-04-01

    The microstructure of investment cast PH 13-8 Mo stainless steel heat-treated to various conditions was studied using light and electron microscopy, electron probe microanalysis, and Mössbauer spectroscopy. The mechanical properties were investigated by using uniaxial tensile testing, hardness testing, and Charpy impact testing. The Β-NiAl strengthening precipitates, though detectable by electron diffraction, were difficult to resolve by transmission electron microscopy (TEM) in specimens aged at low temperatures (566 °C and below). A high dislocation density was observed in the lath martensitic structure. The higher strength and lower ductility observed at low aging temperatures was attributed to both the high dislocation density and the precipitation of Β-NiAl. When samples were aged at high temperatures (> 566 °C), a lower dislocation density and a reverted austenite fraction on the order of 15 pct were observed. Spherical Β-NiAl precipitates were observed in the overaged condition. The decrease in strength and corresponding increase in ductility observed in samples aged at temperatures above 566 °C were attributed to the reverted austenite and recovery. Mechanical properties were improved when the homogenizing temperature and time were increased. Electron probe microanalysis quantified the increased homogeneity realized by increasing homogenizing temperature and time. Elimination of the refrigeration step, which normally follows the solution treatment, did not degrade the mechanical properties. Mössbauer spectroscopy showed only minor decreases in the fraction of retained austenite when refrigeration followed the solution treatment.

  10. Microstructure and mechanical properties of two API steels for iron ore pipelines.

    OpenAIRE

    Godefroid,Leonardo Barbosa; Cândido,Luiz Cláudio; Toffolo,Rodrigo Vicente Bayão; Barbosa,Luiz Henrique Soares

    2014-01-01

    This research compares the mechanical behavior of two API steels (X60 and X70) used in the longest pipeline in the world for the conveyance of iron ore. Tensile tests, Charpy impact tests, CTOD tests and fatigue crack growth tests are performed at ambient temperature. Metallographic examination showed a banded microstructure consisting of polygonal ferrite and pearlite in both steels, with smaller grain size and the presence of a small quantity of bainite in the X70 steel. All the mechanical ...

  11. Impact of effective ocean optical properties on the Pacific subtropical cell: a CGCM study

    Science.gov (United States)

    Yamanaka, G.; Tsujino, H.; Ishizaki, H.; Nakano, H.; Hirabara, M.

    2012-12-01

    The choice of ocean radiant scheme is important for modeling the upper ocean. According to the ocean-only simulation (Yamanaka et al., 2012), introduction of the chlorophyll-a dependent ocean radiant scheme results in the decreased mixed layer depth (MLD), the enhanced subtropical cell (STC), and the cooling of the eastern tropical Pacific sea surface temperature (SST). They also found that the enhanced STC results from the velocity profile change associated with the decreased Ekman boundary layer. However, the impact is not well understood when the air-sea feedback process is at work. This study examines the impact of the effective ocean optical properties on the Pacific mean fields, especially focusing on the STC, using a coupled general circulation model (CGCM). The CGCM we employed is the Meteorological Research Institute Earth System Model (MRI-ESM1). The atmospheric model is TL159L48, and the ocean model has a horizontal resolution of 1 x 0.5 deg. with 51 levels in vertical. Experimental design basically follows the CMIP5 protocol. Two experiments (CTL and SLR runs) are performed to investigate the impact of the effective ocean optical properties. In the CTL run, a conventional ocean radiant heating scheme (Paul and Simpson, 1977) is used, whereas a new ocean radiant heating scheme is used in the SLR run, where the satellite-derived chlorophyll-a distribution is taken into consideration based on Morel and Antoine (1994) as well as the effect of the varying solar angle (Ishizaki and Yamanaka, 2010). Each experiment is integrated during the period from 1985 to 2005. It is found that introduction of the new ocean radiant scheme (SLR run) changes the long-term mean wind pattern in the Pacific: easterly winds are strengthened in the equatorial Pacific, but weakened in the off-equatorial region. In the tropical Pacific, the enhanced equatorial upwelling cools the equatorial SST and the MLD becomes shallower. This is similar to the ocean-only simulation, but is more

  12. Biomass burning aerosol over the Amazon during SAMBBA: impact of chemical composition on radiative properties

    Science.gov (United States)

    Morgan, William; Allan, James; Flynn, Michael; Darbyshire, Eoghan; Hodgson, Amy; Liu, Dantong; O'shea, Sebastian; Bauguitte, Stephane; Szpek, Kate; Langridge, Justin; Johnson, Ben; Haywood, Jim; Longo, Karla; Artaxo, Paulo; Coe, Hugh

    2014-05-01

    Biomass burning represents one of the largest sources of particulate matter to the atmosphere, resulting in a significant perturbation to the Earth's radiative balance coupled with serious impacts on public health. Globally, biomass burning aerosols are thought to exert a small warming effect but with the uncertainty being 4 times greater than the central estimate. On regional scales, the impact is substantially greater, particularly in areas such as the Amazon Basin where large, intense and frequent burning occurs on an annual basis for several months. Absorption by atmospheric aerosols is underestimated by models over South America, which points to significant uncertainties relating to Black Carbon (BC) aerosol properties. Initial results from the South American Biomass Burning Analysis (SAMBBA) field experiment, which took place during September and October 2012 over Brazil on-board the UK Facility for Airborne Atmospheric Measurement (FAAM) BAe-146 research aircraft, are presented here. Aerosol chemical composition was measured by an Aerodyne Aerosol Mass Spectrometer (AMS) and a DMT Single Particle Soot Photometer (SP2). The physical, chemical and optical properties of the aerosols across the region will be characterized in order to establish the impact of biomass burning on regional air quality, weather and climate. The aircraft sampled a range of conditions including sampling of pristine Rainforest, fresh biomass burning plumes, regional haze and elevated biomass burning layers within the free troposphere. The aircraft sampled biomass burning aerosol across the southern Amazon in the states of Rondonia and Mato Grosso, as well as in a Cerrado (Savannah-like) region in Tocantins state. This presented a range of fire conditions, both in terms of their number, intensity, vegetation-type and their combustion efficiencies. Near-source sampling of fires in Rainforest environments suggested that smouldering combustion dominated, while flaming combustion dominated

  13. Structure property relationships in various filled polymers

    Science.gov (United States)

    Yu, Jiong

    The toughness of impact modified poly(vinyl chloride) (PVC) compounds was examined using a modified Charpy test. Increasing impact speed resulted in a quasi-brittle to ductile transition in all PVC compounds. In the quasi-brittle region, a PVC of 56,000 Mw fractured through a craze-like damage zone that could be described by a modified Dugdale model. Furthermore, the same molecular weight PVC modified with either 10 pph chlorinated polyethylene (CPE) or 10 pph methylmethacrylate-butadiene-styrene (MBS) impact modifier also conformed to the Dugdale model with the craze-like damage zone. It was found that CPE effectively improved the impact performance of PVC by shifting the quasi-brittle to ductile transition to a higher loading rate. Compared to CPE, MBS was found to be a better impact modifier and resulted in a higher quasi-brittle to ductile transition loading rate in the same PVC matrix. Fracture initiation toughness of all the materials was described by the Hayes-Williams modification of the Dugdale model. The intrinsic brittle fracture energy obtained by extrapolation to zero craze length was determined only by the PVC matrix and was independent of the impact modifier. However, the kinetics of craze growth, and hence the response to rapid loading, depended on the impact modifier. Increasing molecular weight of the PVC resin resulted in a more complex damage zone that was not amendable to the Dugdale analysis. A new in-situ infusion method was used to incorporate small amounts (ca. 1wt%) of metal and metal oxide particles into a polymer matrix. Nano-sized particles were observed by both transmission electron microscopy (TEM) and atomic force microscopy (AFM). Oxygen (O2) and carbon dioxide (CO2) transport properties of the infused materials were investigated using a dynamic diffusion approach in which both testing and purge gases can be controlled. It was discovered that trace amounts (ca. 2%) of hydrogen (H2) in the purge gas was sufficient to considerably

  14. Comparison on Mechanical Properties of SA508 Gr.3 Cl.1, Cl.2, and Gr.4N Low Alloy Steels for Pressure Vessels

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min-Chul; Park, Sang-Gyu; Lee, Bong-Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Ki-Hyoung [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2014-10-15

    In this study, microstructure and mechanical properties of SA508 Gr.3 Cl. 1, Cl.2, and Gr.4N low alloy steels are characterized to compare their properties. To evaluate the fracture toughness in the transition region, the master curve method according to ASTM E1921 was adopted in the cleavage transition region. Tensile tests and Charpy impact tests were also performed to evaluate the mechanical properties, and a microstructural investigation was carried out. The microstructure and mechanical properties of SA508 Gr.3 Cl.1, Cl2 and Gr.4N low alloy steels were characterized.. The predominant microstructure of SA508 Gr.4N model alloy is tempered martensite, while SA508 Gr.3 Cl.1 and Cl.2 steels show a typical tempered upper bainitic structure. SA508 Gr. 4N model alloy shows the best strength and transition behavior among the three SA508 steels. SA508 Gr.3 Cl.2 steel also has quite good strength, but there is a loss of toughness.

  15. Tensile strength and impact resistance properties of materials used in prosthetic check sockets, copolymer sockets, and definitive laminated sockets

    OpenAIRE

    Maria J. Gerschutz, PhD; Michael L. Haynes, MS; Derek M. Nixon, BS; James M. Colvin, MS

    2011-01-01

    Prosthetic sockets serve as the interface between people with amputations and their prostheses. Although most materials used to make prosthetic sockets have been used for many years, knowledge of these materials' properties is limited, especially after they are subjected to fabrication processes. This study evaluated tensile and impact properties of the current state-of-the-art materials used to fabricate prosthetic check sockets, copolymer sockets, and definitive laminated sockets. Thermolyn...

  16. Influence of Rare Earths on Improve Impact Property of Structural Alloy Steel with Extra Low Sulfur and Oxygen

    Institute of Scientific and Technical Information of China (English)

    Guo Feng; Lin Qin

    2007-01-01

    The influence of rare earth lanthanum and cerium on impact property of structural alloy steel with extra low sulfur and oxygen was studied by impact test and microanalysis. The results showed that rare earths increased impact power of the steel when their contents were about 0.005%. Proper addition of rare earths could purify grain boundaries and decrease amount of inclusions, and reduced the possibility of crack growth along grain boundaries and through inclusions. Therefore, such steel could absorb more crack growth energy while it was impacted. However, if the content of rare earths is excessive, the grain boundary would be weakened and brittle-hard phosphates and Fe-RE intermetallic would be formed, which worsened impact toughness of steel.

  17. 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

  18. Perceived Impact of a Land and Property Rights Program on Violence Against Women in Rural Kenya: A Qualitative Investigation.

    Science.gov (United States)

    Hilliard, Starr; Bukusi, Elizabeth; Grabe, Shelly; Lu, Tiffany; Hatcher, Abigail M; Kwena, Zachary; Mwaura-Muiru, Esther; Dworkin, Shari L

    2016-03-06

    The current study focuses on a community-led land and property rights program in two rural provinces in western Kenya. The program was designed to respond to women's property rights violations to reduce violence against women and HIV risks at the community level. Through in-depth interviews with 30 women, we examine the perceived impact that this community-level property rights program had on violence against women at the individual and community level. We also examine perceptions as to how reductions in violence were achieved. Finally, we consider how our findings may aid researchers in the design of structural violence-prevention strategies.

  19. The Impact of Changes of Property Rights on Farmland Use:An Empirical Study of China during Transition

    Institute of Scientific and Technical Information of China (English)

    Chen Zhigang; Qu Futian; Wang Qing

    2007-01-01

    In China, farmland property rights characterized by the household-responsibility system (HRS) have been improved since the reform and opening-up. The rights of use, transfer and gain become more stable, authorized and complete. This paper firstly analyzes the impact on farmland productivity, which comes from the improvement of farmland property rights. Then, an econometric model is built to test the above analysis. It concludes that changes of property rights will affect farmland performance in China. In the end, some policy implications are explored for further reforms.

  20. Strategy to document heterogeneity in soil properties and its impact on water transfers from slope to catchment scales

    Science.gov (United States)

    Cohard, J.; Robert, D.; Descloitres, M.; Vandervaere, J.; Braud, I.; Vauclin, M.

    2011-12-01

    Heterogeneity in soil properties has been identified to impact water transfers at different scales from vertical column, hillslopes to watershed. Thus Distributed physically based hydrological models require distributed hydraulic characteristics to quantify these impacts. To characterize soil properties and their heterogeneity, a multi-scale sampling strategy was proposed based on distributed information including electromagnetic survey maps, topography and land use coverage. Each identified units are characterized by there hydraulic properties including in situ infiltration tests. This strategy was applied over the Ara Catchment (12km2) in northern Benin. It has been instrumented in the framework of the AMMA-Catch experimental network in West Africa, to better determine water resources and to investigate possible hydrological retro-action on monsoon cycle. From hydrological point of view, distributed soil hydraulic properties are supposed to impact water transfers and watershed dynamics all along the monsoon cycle. To document this heterogeneity, an electrical conductivity map and geological survey was used as starting points to identify the ground structures which align with the north-south direction with a dip angle of 20° east. A total of 20 pits have been opened to document the 0-2m horizons, and 2 more for the 0-5m horizons. 3 pits were digged within each geological structure areas at the surface. In each pit, the retention and hydraulic conductivity curves of each pedological horizon were characterized with three replicates. This database is used to document the variability of these properties and to produce soil hydraulic property maps. Using the variability information, we tested their impact with the Parflow-CLM 3D distributed model. It was run in an homogeneous configuration and compared with a data controlled heterogeneous configuration. The latest is prepared using a turning band algorithm to distribute soil hydraulic properties.

  1. 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.

  2. Impacts of cloud heterogeneities on cirrus optical properties retrieved from spatial thermal infrared radiometry

    Directory of Open Access Journals (Sweden)

    T. Fauchez

    2014-08-01

    Full Text Available This paper presents a study, based on simulations, of the impact of cirrus cloud heterogeneities on the retrieval of cloud parameters (optical thickness and effective diameter for the Imaging Infrared Radiometer (IIR on board CALIPSO. Cirrus clouds are generated by the stochastic model 3DCLOUD for two different cloud fields and for several averaged cloud parameters. One is obtained from a cirrus observed on the 25 May 2007 during the airborne campaign CIRCLE-2 and the other is a cirrus uncinus. The radiative transfer is simulated with the code 3DMCPOL. To assess the errors due to cloud heterogeneities, two related retrieval algorithms are used: (i The split window technique to retrieve the ice crystal effective diameter and (ii an algorithm similar to the IIR operational algorithm to retrieve the effective emissivity and the effective optical thickness. Differences between input parameters and retrieved parameters are compared as a function of different cloud properties such as the mean optical thickness, the heterogeneity parameter and the effective diameter. The optical thickness heterogeneity for each 1 km × 1 km observation pixel is represented by the optical thickness standard deviation computed using 100 m × 100 m subpixels. We show that optical thickness heterogeneity may have a strong impact on the retrieved parameters, mainly due to the Plane Parallel Approximation (PPA. In particular, for cirrus cloud with ice crystal size of approximately 10 μm, the averaged error on the retrieved effective diameter is about 2.5 μm (~ 25% and on the effective optical thickness of about −0.20 (~ 12%. Then, these biases decrease with the increase of the ice effective size due to a decrease of the cloud absorption and thus of the PPA bias. Cloud heterogeneity effects are much more higher than other possible sources of error. They become larger than the retrieval incertitude of the IIR algorithm from a standard deviation of the optical thickness

  3. Impact of gas injection on the apparent viscosity and viscoelastic property of waste activated sewage sludge.

    Science.gov (United States)

    Bobade, Veena; Baudez, Jean Christophe; Evans, Geoffery; Eshtiaghi, Nicky

    2017-05-01

    Gas injection is known to play a major role on the particle size of the sludge, the oxygen transfer rate, as well as the mixing efficiency of membrane bioreactors and aeration basins in the waste water treatment plants. The rheological characteristics of sludge are closely related to the particle size of the sludge floc. However, particle size of sludge floc depends partly on the shear induced in the sludge and partly on physico-chemical nature of the sludge. The objective of this work is to determine the impact of gas injection on both the apparent viscosity and viscoelastic property of sludge. The apparent viscosity of sludge was investigated by two methods: in-situ and after sparging. Viscosity curves obtained by in-situ measurement showed that the apparent viscosity decreases significantly from 4000 Pa s to 10 Pa s at low shear rate range (below 10 s(-1)) with an increase in gas flow rate (0.5LPM to 3LPM); however the after sparging flow curve analysis showed that the reduction in apparent viscosity throughout the shear rate range is negligible to be displayed. Torque and displacement data at low shear rate range revealed that the obtained lower apparent viscosity in the in-situ method is not the material characteristics, but the slippage effect due to a preferred location of the bubbles close to the bob, causing an inconsistent decrease of torque and increase of displacement at low shear rate range. In linear viscoelastic regime, the elastic and viscous modulus of sludge was reduced by 33% & 25%, respectively, due to gas injection because of induced shear. The amount of induced shear measured through two different tests (creep and time sweep) were the same. The impact of this induced shear on sludge structure was also verified by microscopic images.

  4. The impact of subgroup type and subgroup configurational properties on work team performance.

    Science.gov (United States)

    Carton, Andrew M; Cummings, Jonathon N

    2013-09-01

    Scholars have invoked subgroups in a number of theories related to teams, yet certain tensions in the literature remain unresolved. In this article, we address 2 of these tensions, both relating to how subgroups are configured in work teams: (a) whether teams perform better with a greater number of subgroups and (b) whether teams perform better when they have imbalanced subgroups (majorities and minorities are present) or balanced subgroups (subgroups are of equal size). We predict that the impact of the number and balance of subgroups depends on the type of subgroup-whether subgroups are formed according to social identity (i.e., identity-based subgroups) or information processing (i.e., knowledge-based subgroups). We first propose that teams are more adversely affected by 2 identity-based subgroups than by any other number, yet the uniquely negative impact of a 2-subgroup configuration is not apparent for knowledge-based subgroups. Instead, a larger number of knowledge-based subgroups is beneficial for performance, such that 2 subgroups is worse for performance when compared with 3 or more subgroups but better for performance when compared with no subgroups or 1 subgroup. Second, we argue that teams perform better when identity-based subgroups are imbalanced yet knowledge-based subgroups are balanced. We also suggest that there are interactive effects between the number and balance of subgroups-however, the nature of this interaction depends on the type of subgroup. To test these predictions, we developed and validated an algorithm that measures the configurational properties of subgroups in organizational work teams. Results of a field study of 326 work teams from a multinational organization support our predictions.

  5. Quantifying the impact of AGN and nebular emission on stellar population properties with REBETIKO

    Science.gov (United States)

    Cardoso, L. S. M.; Gomes, J. M.; Papaderos, P.

    2016-06-01

    Spectral synthesis enables the reconstruction of the star formation and chemical evolution histories (SFH & CEH) of a galaxy that are encoded in its spectral energy distribution (SED). Most state-of-the-art population synthesis codes however consider only purely stellar emission and are hence inadequate for modelling studies of galaxies where non-stellar emission components contribute significantly to the SED. This work combines evolutionary and population synthesis techniques to quantify the impact of active galactic nucleus (AGN) and nebular emission on the determination of the stellar population properties in galaxies. We have developed an evolutionary synthesis code called REBETIKO - Reckoning galaxy Emission By means of Evolutionary Tasks with Input Key Observables - to compute and study the time evolution of the SED of AGN-hosts and starburst galaxies. Our code takes into account the main ingredients of a galaxy's SED (e.g. non-thermal emission and/or nebular continuum and lines) for various commonly used parameterizations of the SFH, such as instantaneous burst, constant, exponentially decreasing, and gradually increasing peaking at a redshift between 1-10. Synthetic SEDs computed with REBETIKO have been subsequently fitted with the STARLIGHT population synthesis code (PSC) which can be regarded as representative for currently available state-of-the-art (i.e. purely stellar) PSCs. The objective is to study the impact of non-stellar SED components on the recovery of the true total stellar mass M_{star} and SFH of a galaxy, as well as other evolutionary properties, such as CEH and light- and mass-weighted mean stellar age and metallicity. We find that purely stellar fits in galaxies with a strong non-stellar continuum (e.g. Seyfert and/or starburst galaxies) can for instance overestimate M_{star} by up to 3 orders of magnitude, while the mean stellar age and metallicity can deviate from their true values up to 2 and 4 dex, respectively. These results imply

  6. Impact of within-field variability in soil hydraulic properties on transpiration fluxes and crop yields: A numerical study

    NARCIS (Netherlands)

    Hupet, F.; Dam, van J.C.; Vanclooster, M.

    2004-01-01

    By means of numerical modeling we investigate the impact of within-field variability in the soil hydraulic properties on actual transpiration and dry matter yield for three different climate scenarios. We first show that the sensitivity of the simulated actual transpiration and dry matter yield to s

  7. Impact of the substitution of rice bran on rheological properties of dough and in the new product development.

    Science.gov (United States)

    Rice bran is a nutrient-rich co-product of the rice milling industries. The impact of adding 2-20% rice bran in wheat flour on the rheological behavior of the dough was investigated using the instruments, Farinograph, Consistograph, and Alveograph. The changes in physico-chemical properties were fo...

  8. Impact of land use practices on faunal abundance, nutrient dynamics and biochemical properties of desert pedoecosystem.

    Science.gov (United States)

    Tripathi, G; Sharma, B M

    2005-11-01

    Increased dependence of resource-poor rural communities on soils of low inherent fertility are the major problem of desert agroecosystem. Agrisilviculture practices may help to conserve the soil biota for maintaining essential soil properties and processes in harsh climate. Therefore, the impacts of different land use systems on faunal density, nutrient dynamics and biochemical properties of soil were studied in agrisilviculture system of Indian desert. The selected fields had trees (Zizyphus mauritiana, Prosopis cineraria, Acacia nilotica) and crops (Cuminum cyminum, Brassica nigra, Triticum aestivum) in different combinations. Populations of Acari, Myriapoda, Coleoptera, Collembola, other soil arthropods and total soil fauna showed significant changes with respect to different land use practices and tree species, indicating a strong relation between above and below ground biodiversity. The Coleoptera exhibited greatest association with all agrisilviculture fields. The Z. mauritiana system indicated highest facilitative effects (RTE value) on all groups of soil fauna. Soil temperature, moisture, organic carbon, nitrate- and ammonical-nitrogen, available phosphorus, soil respiration and dehydrogenase activity were greater under tree than that of tree plus cropping system. It showed accumulation of nitrate-nitrogen in tree field and more utilization by crops in cultivated lands. Positive and significant correlation among organic carbon, nitrate- and ammonical-nitrogen, phosphorus, soil respiration and dehydrogenase activity clearly reflects increase in soil nutrients with the increase in microbial and other biotic activity. P. cineraria field was the best pedoecosystem, while C. cyminum was the best winter crop for cultivation in desert agroforestry system for soil biological health and soil sustainability. The increase in organic carbon, soil nutrients and microbial activity is associated with the increase in soil faunal population which reflect role of soil fauna

  9. Numerical analysis of thermal impact on hydro-mechanical properties of clay

    Directory of Open Access Journals (Sweden)

    Xuerui Wang

    2014-10-01

    Full Text Available As is known, high-level radioactive waste (HLW is commonly heat-emitting. Heat output from HLW will dissipate through the surrounding rocks and induce complex thermo-hydro-mechanical-chemical (THMC processes. In highly consolidated clayey rocks, thermal effects are particularly significant because of their very low permeability and water-saturated state. Thermal impact on the integrity of the geological barriers is of most importance with regard to the long-term safety of repositories. This study focuses on numerical analysis of thermal effects on hydro-mechanical properties of clayey rock using a coupled thermo-mechanical multiphase flow (TH2M model which is implemented in the finite element programme OpenGeoSys (OGS. The material properties of the numerical model are characterised by a transversal isotropic elastic model based on Hooke's law, a non-isothermal multiphase flow model based on van Genuchten function and Darcy's law, and a transversal isotropic heat transport model based on Fourier's law. In the numerical approaches, special attention has been paid to the thermal expansion of three different phases: gas, fluid and solid, which could induce changes in pore pressure and porosity. Furthermore, the strong swelling and shrinkage behaviours of clayey material are also considered in the present model. The model has been applied to simulate a laboratory heating experiment on claystone. The numerical model gives a satisfactory representation of the observed material behaviour in the laboratory experiment. The comparison of the calculated results with the laboratory findings verifies that the simulation with the present numerical model could provide a deeper understanding of the observed effects.

  10. Black carbon mixing state impacts on cloud microphysical properties: effects of aerosol plume and environmental conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ching, Ping Pui; Riemer, Nicole; West, Matthew

    2016-05-27

    Black carbon (BC) is usually mixed with other aerosol species within individual aerosol particles. This mixture, along with the particles' size and morphology, determines the particles' optical and cloud condensation nuclei properties, and hence black carbon's climate impacts. In this study the particle-resolved aerosol model PartMC-MOSAIC was used to quantify the importance of black carbon mixing state for predicting cloud microphysical quantities. Based on a set of about 100 cloud parcel simulations a process level analysis framework was developed to attribute the response in cloud microphysical properties to changes in the underlying aerosol population ("plume effect") and the cloud parcel cooling rate ("parcel effect"). It shows that the response of cloud droplet number concentration to changes in BC emissions depends on the BC mixing state. When the aerosol population contains mainly aged BC particles an increase in BC emission results in increasing cloud droplet number concentrations ("additive effect"). In contrast, when the aerosol population contains mainly fresh BC particles they act as sinks for condensable gaseous species, resulting in a decrease in cloud droplet number concentration as BC emissions are increased ("competition effect"). Additionally, we quantified the error in cloud microphysical quantities when neglecting the information on BC mixing state, which is often done in aerosol models. The errors ranged from -12% to +45% for the cloud droplet number fraction, from 0% to +1022% for the nucleation-scavenged black carbon (BC) mass fraction, from -12% to +4% for the effective radius, and from -30% to +60% for the relative dispersion.

  11. Numerical analysis of thermal impact on hydro-mechanical properties of clay

    Institute of Scientific and Technical Information of China (English)

    Xuerui Wang; Hua Shao; Jürgen Hesser; Chunliang Zhang; Wenqing Wang; Olaf Kolditz

    2014-01-01

    As is known, high-level radioactive waste (HLW) is commonly heat-emitting. Heat output from HLW will dissipate through the surrounding rocks and induce complex thermo-hydro-mechanical-chemical (THMC) processes. In highly consolidated clayey rocks, thermal effects are particularly significant because of their very low permeability and water-saturated state. Thermal impact on the integrity of the geological barriers is of most importance with regard to the long-term safety of repositories. This study focuses on numerical analysis of thermal effects on hydro-mechanical properties of clayey rock using a coupled thermo-mechanical multiphase flow (TH2M) model which is implemented in the finite element programme OpenGeoSys (OGS). The material properties of the numerical model are characterised by a transversal isotropic elastic model based on Hooke’s law, a non-isothermal multiphase flow model based on van Genuchten function and Darcy’s law, and a transversal isotropic heat transport model based on Fourier’s law. In the numerical approaches, special attention has been paid to the thermal expansion of three different phases: gas, fluid and solid, which could induce changes in pore pressure and porosity. Furthermore, the strong swelling and shrinkage behaviours of clayey material are also considered in the present model. The model has been applied to simulate a laboratory heating experiment on claystone. The numerical model gives a satisfactory representation of the observed material behaviour in the laboratory experiment. The comparison of the calculated results with the laboratory findings verifies that the simulation with the present numerical model could provide a deeper understanding of the observed effects.

  12. Antioxidant properties of caroot juices and their impact on intestinal and probiotic bacteria

    Directory of Open Access Journals (Sweden)

    Aleksandra Duda-Chodak

    2015-08-01

    Full Text Available There is a growing interest in non-dairy probiotic products. The main aim of the study was to evaluate the impact of juice prepared from 15 various cultivars of carrot on the growth of representatives of human intestinal microbiota (Bifidobacterium catenulatum, Escherichia coli and probiotic strains (Lactobacillus acidophilus LA-5, Lactobacillus casei 01. Carrot juice was added to liquid medium at a final concentration of 5.0% and their impact on the bacteria number was assessed by measurement of the turbidity after 24 h of culture. The number of cells was expressed as % of positive control (medium without juice addition. Juices prepared from all tested cultivars of carrot inhibited the growth of Bifidobacterium catenulatum, and the strongest inhibitory effect was observed for juices obtained from the 'Kongo F1' cultivar (3.40 ±2.85% of positive control, 'Rumba F1'(4.17 ±2.27% and 'Broker F1' (5.35 ±2.14%. The majority of tested juices also inhibited the growth of E. coli, but those prepared from the 'Niland F1', 'Napa F1', 'Afro F1'and 'Samba F1' cultivars stimulated the growth of this bacterium. The probiotic strains were less sensitive to carrot juice impact than intestinal species, however both stimulation and inhibition could be observed. Juices made from the cultivars 'Kongo F1' and 'Deep Purple F1' acted negatively on the growth of both probiotic strains, while juice from 'Bangor F1' cultivar inhibited L. casei 01 growth, but stimulated the growth of LA-5. The obtained results suggest that 'Kongo F1' and 'Deep Purple F1' cultivars are not suitable as an additive or raw material for the production of probiotic products, because of their inhibitory properties against probiotic strains. Concluding, carrots can be used as raw material for the production of probiotic beverages, however both the cultivar of carrot and the strains of probiotic bacteria used for the production should be selected carefully. The most suitable for production of

  13. Investigating the influence of infill percentage on the mechanical properties of fused deposition modelled ABS parts

    Directory of Open Access Journals (Sweden)

    Kenny Álvarez

    2016-09-01

    Full Text Available 3D printing is a manufacturing process that is usually used for modeling and prototyping. One of the most popular printing techniques is fused deposition modeling (FDM, which is based on adding melted material layer by layer. Although FDM has several advantages with respect to other manufacturing materials, there are several problems that have to be faced. When setting the printing options, several parameters have to be taken into account, such as temperature, speed, infill percentage, etc. Selecting these parameters is often a great challenge for the user, and is generally solved by experience without considering the influence of variations in the parameters on the mechanical properties of the printed parts.This article analyzes the influence of the infill percentage on the mechanical properties of ABS (Acrylonitrile Butadiene Styrene printed parts. In order to characterize this influence, test specimens for tensile strength and Charpy tests were printed with a Makerbot Replicator 2X printer, in which the infill percentage was varied but the rest of the printing parameters were kept constant. Three different results were analyzed for these tests: tensile strength, impact resistance, and effective printing time. Results showed that the maximum tensile force (1438N and tensile stress (34,57MPa were obtained by using 100% infill. The maximum impact resistance, 1,55J, was also obtained with 100% infill. In terms of effective printing time, results showed that printing with an infill range between 50% and 98% is not recommended, since the effective printing time is higher than with a 100% infill and the tensile strength and impact resistance are smaller. In addition, in comparing the results of our analysis with results from other authors, it can be concluded that the printer type and plastic roll significantly influence the mechanical properties of ABS parts.

  14. Microstructures and Mechanical Properties of Weld Metal and Heat-Affected Zone of Electron Beam-Welded Joints of HG785D Steel

    Science.gov (United States)

    Zhang, Qiang; Han, Jianmin; Tan, Caiwang; Yang, Zhiyong; Wang, Junqiang

    2016-12-01

    Vacuum electron beam welding (EBW) process was employed to butt weld 10-mm-thick HG785D high-strength steels. The penetration into the steel was adjusted by beam current. Microstructures at weld metal and heat-affected zone (HAZ) regions were comparatively observed. Mechanical properties of the EBWed joints including Vickers hardness, tensile and Charpy impact tests were evaluated. The results indicated that microstructures at the weld metal consisted of coarse lath martensite and a small amount of acicular martensite, while that in the HAZ was tempered sorbite and martensite. The grain size in the weld metal was found to be larger than that in the HAZ, and its proportion in weld metal was higher. The hardness in the weld metal was higher than the HAZ and base metal. The tensile strength and impact toughness in the HAZ was higher than that in the weld metal. All the behaviors were related to microstructure evolution caused by higher cooling rates and state of base metal. The fracture surfaces of tensile and impact tests on the optimized joint were characterized by uniform and ductile dimples. The results differed significantly from that obtained using arc welding process.

  15. The effect of cobalt and carbon the microstructure and mechanical properties of martensitic precipitation strengthened stainless steels

    Science.gov (United States)

    Komolwit, Piyamanee

    The effects of cobalt additions on the mechanical properties and strengthening mechanisms of a martensitic precipitation strengthening stainless steel whose composition is (in wt. %) 0.005C/12Cr/5Mo/1.5Ni has been investigated for cobalt levels of 9, 12, 15, 18, and 21 wt. %. Hardness, yield strength and ultimate tensile strength increase as the cobalt content increases, while the Charpy impact energy decreases as tempering temperature increases. At the peak strength of the 21 wt. % cobalt alloy, which is after tempering at 550°C, the yield strength is 1772 MPa, the ultimate tensile strength is 1916 MPa, and the hardness is 55 HRC. The martensite start temperature decreases as cobalt content increases. In this alloys there is no retained austenite after austenitizing, oil quenching and then refrigerating in liquid nitrogen prior to tempering. These alloys contain no reverted austenite except for the 21 wt. % cobalt alloy after tempering at 600°C. Optical micrographs show lath martensite as the matrix for all alloys. Increasing cobalt content has little effect on prior austenite grain size. Transmission electron micrographs show a substructure of lath martensite and a b.c.c. matrix for all alloys after tempering at 525°C. Precipitates were observed in dark field images at all cobalt levels and were seen in bright field images of 21 wt. % cobalt alloy. One of the precipitates was identified as omega phase with a trigonal structure with lattice parameter of a = b = 4.1 A, c = 2.51 A with c/a = 0.612. The particle size appears to be 17 nanometers in diameter and they were found only in the foils of 21 wt. % cobalt alloy. The second precipitate type was identified as a monoclinic phase with a monoclinic structure with lattice parameters of a = 5.464 A, b = 2.843 A, c = 3.178 A, and alpha = gamma = 90° and beta = 63.4°. The monoclinic phase particles appear to significantly contribute to the strength of these alloys, with particles size and volume fraction

  16. The Impact of Wind Power Projects on Residential Property Values in the United States: A Multi-Site Hedonic Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hoen, Ben; Wiser, Ryan; Cappers, Peter; Thayer, Mark; Sethi, Gautam

    2009-12-02

    With wind energy expanding rapidly in the U.S. and abroad, and with an increasing number of communities considering wind power development nearby, there is an urgent need to empirically investigate common community concerns about wind project development. The concern that property values will be adversely affected by wind energy facilities is commonly put forth by stakeholders. Although this concern is not unreasonable, given property value impacts that have been found near high voltage transmission lines and other electric generation facilities, the impacts of wind energy facilities on residential property values had not previously been investigated thoroughly. The present research collected data on almost 7,500 sales of singlefamily homes situated within 10 miles of 24 existing wind facilities in nine different U.S. states. The conclusions of the study are drawn from eight different hedonic pricing models, as well as both repeat sales and sales volume models. The various analyses are strongly consistent in that none of the models uncovers conclusive evidence of the existence of any widespread property value impacts that might be present in communities surrounding wind energy facilities. Specifically, neither the view of the wind facilities nor the distance of the home to those facilities is found to have any consistent, measurable, and statistically significant effect on home sales prices. Although the analysis cannot dismiss the possibility that individual homes or small numbers of homes have been or could be negatively impacted, it finds that if these impacts do exist, they are either too small and/or too infrequent to result in any widespread, statistically observable impact.

  17. Impact of a low intensity controlled-fire in some chemical soil properties.

    Science.gov (United States)

    Martínez-Murillo, Juan F.; Hueso-González, Paloma; Aranda-Gómez, Francisco; Damián Ruiz-Sinoga, José

    2014-05-01

    Some changes in chemical soil properties can be observed after fires of low intensities. pH and electric conductivity tend to increase, while C/N ratio decrease. In the case of organic matter, the content can increase due to the massive incorporation of necromass including, especially, plants and roots. The aim of this study is to assess the impact of low intensity and controlled fire in some soil properties in field conditions. El Pinarillo experimental area is located in South of Spain. Two set of closed plots were installed (24 m2: 12 m length x 2 m width). One of them was remained as control with the original vegetation cover (Mediterranean matorral: Rosmarinus officinalis, Cistus clusii, Lavandula stoechas, Chamaeropos humilis, Thymus baetica), and the other one was burnt in a controlled-fire in 2011. Weather conditions and water content of vegetation influenced in the intensity of fire (low). After the controlled-fire, soil surface sample (0-5 cm) were taken in both set of plots (B, burnt soil samples; C, control soil samples). Some soil chemical properties were analysed: organic matter content (OM), C/N ratio, pH and electrical conductivity (EC). Some changes were observed in B corroborating a controlled-fire of low intensity. pH remained equal after fire (B: pH=7.7±0.11; C: pH=7.7±0.04). An increment was obtained in the case of EC (B: EC=0.45 mScm-1±0.08 mScm-1; C: EC=0.35 mScm-1±0.07 mScm-1) and OM (B: OM=8.7%±3.8%; C: pH=7.3%±1.5%). Finally, C/N ratio decreased after fire respect to the control and initial conditions (B: C/N=39.0±14.6; C: C/N =46.5±10.2).

  18. Chitosan-Based Nano-Embedded Microparticles: Impact of Nanogel Composition on Physicochemical Properties.

    Science.gov (United States)

    Islam, Paromita; Water, Jorrit J; Bohr, Adam; Rantanen, Jukka

    2016-12-22

    Chitosan-based nanogels have been widely applied as drug delivery vehicles. Spray-drying of said nanogels allows for the preparation of dry powder nano-embedded microparticles. In this work, chitosan-based nanogels composed of chitosan, alginate, and/or sodium tri-penta phosphate were investigated, particularly with respect to the impact of composition on the resulting physicochemical properties. Different compositions were obtained as nanogels with sizes ranging from 203 to 561 nm. The addition of alginate and exclusion of sodium tri-penta phosphate led to an increase in nanogel size. The nanogels were subsequently spray-dried to form nano-embedded microparticles with trehalose or mannitol as matrix excipient. The microparticles of different composition were mostly spherical with a smooth surface and a mass median aerodynamic diameter of 6-10 µm. Superior redispersibility was observed for microparticles containing amorphous trehalose. This study demonstrates the potential of nano-embedded microparticles for stabilization and delivery of nanogel-based delivery systems.

  19. The formation, properties and impact of secondary organic aerosol: current and emerging issues

    Directory of Open Access Journals (Sweden)

    M. Hallquist

    2009-02-01

    Full Text Available Secondary organic aerosol (SOA accounts for a significant fraction of ambient tropospheric aerosol and a detailed knowledge of the formation, properties and transformation of SOA is therefore required to evaluate its impact on atmospheric processes, climate and human health. The chemical and physical processes associated with SOA formation are complex and varied, and, despite considerable progress in recent years, a quantitative and predictive understanding of SOA formation does not exist and therefore represents a major research challenge in atmospheric science. This review begins with a description of the current state of knowledge on the global SOA budget and the atmospheric degradation mechanisms for SOA precursors. The topic of gas-particle partitioning theory is followed by an account of the analytical techniques used to determine the chemical composition of SOA. A survey of recent laboratory, field and modeling studies is also presented. The following topical and emerging issues are highlighted and discussed in detail; molecular characterization of biogenic SOA constituents, condensed phase reactions and oligomerization, the interaction of atmospheric organic components with sulfuric acid, the chemical and photochemical processing of organics in the atmospheric aqueous phase, aerosol formation from real plant emissions, interaction of atmospheric organic components with water, thermodynamics and mixtures in atmospheric models. Finally, the major challenges ahead in laboratory, field and modeling studies of SOA are discussed and recommendations for future research directions are proposed.

  20. Impact of Argon gas on optical and electrical properties of Carbon thin films

    Science.gov (United States)

    Usman, Arslan; Rafique, M. S.; Shaukat, S. F.; Siraj, Khurram; Ashfaq, Afshan; Anjum, Safia; Imran, Muhammad; Sattar, Abdul

    2016-12-01

    Nanostructured thin films of carbon were synthesized and investigated for their electrical, optical, structural and surface properties. Pulsed Laser Deposition (PLD) technique was used for the preparation of these films under Argon gas environment. A KrF Laser (λ=248 nm) was used as source of ablation and plasma formation. It was observed that the carbon ions and the background gas environment has deep impact on the morphology as well as on the microstructure of the films. Time of Flight (TOF) method was used to determine the energies of the ablated carbon ions. The morphology of film surfaces deposited at various argon pressure was analysed using an atomic force microscope. The Raman spectroscopic measurement reveal that there is shift in phase from sp3 to sp2 and a decrease in FWHM of G band, which is a clear indication of enhanced graphitic clusters. The electrical resistivity was also reduced from 85.3×10-1 to 2.57×10-1 Ω-cm. There is an exponential decrease in band gap Eg of the deposited films from 1.99 to 1.37 eV as a function of argon gas pressure.

  1. Secondary materials: Engineering properties, environmental consequences, and social and economic impacts. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Breslin, V.; Reaven, S.; Schwartz, M.; Swanson, L.; Zweig, M.; Bortman, M.; Schubel, J.

    1993-08-01

    This report investigates two secondary materials, plastic lumber made from mixed plastic waste, and cement blocks and structures made with incinerator ash. Engineering properties, environmental impacts, and energy costs and savings of these secondary materials are compared to standard lumber products and cement blocks. Market capacity and social acceptance of plastic lumber and stabilized ash products are analyzed. These secondary materials apparently have potential markets; however, their economic value is primarily that they will not take up landfill space. For plastic lumber and stabilized incinerator ash products, marine and highway construction seem ideal public works applications. Incinerator ash may be suitable to use in seawalls, jetties, fishing reefs, highway barriers, and roadbed applications. Docks, piers, highway sound barriers, parking stops, and park furniture may all be made from plastic lumber. To encourage public acceptance and improve the market potential of secondary materials, these activities could be beneficial: industry should emphasize developing useful, long-lived products; industry and governments should create product performance criteria; government should provide rigorous testing and demonstration programs; and government and industry should cooperate to improve public outreach and educational programs.

  2. Impact of Simulated Microgravity on Cytoskeleton and Viscoelastic Properties of Endothelial Cell

    Science.gov (United States)

    Janmaleki, M.; Pachenari, M.; Seyedpour, S. M.; Shahghadami, R.; Sanati-Nezhad, A.

    2016-01-01

    This study focused on the effects of simulated microgravity (s-μg) on mechanical properties, major cytoskeleton biopolymers, and morphology of endothelial cells (ECs). The structural and functional integrity of ECs are vital to regulate vascular homeostasis and prevent atherosclerosis. Furthermore, these highly gravity sensitive cells play a key role in pathogenesis of many diseases. In this research, impacts of s-μg on mechanical behavior of human umbilical vein endothelial cells were investigated by utilizing a three-dimensional random positioning machine (3D-RPM). Results revealed a considerable drop in cell stiffness and viscosity after 24 hrs of being subjected to weightlessness. Cortical rigidity experienced relatively immediate and significant decline comparing to the stiffness of whole cell body. The cells became rounded in morphology while western blot analysis showed reduction of the main cytoskeletal components. Moreover, fluorescence staining confirmed disorganization of both actin filaments and microtubules (MTs). The results were compared statistically among test and control groups and it was concluded that s-μg led to a significant alteration in mechanical behavior of ECs due to remodeling of cell cytoskeleton. PMID:27581365

  3. Impacts of hydrogen dilution on growth and optical properties of a-SiC:H films

    Institute of Scientific and Technical Information of China (English)

    HU Zhihua; LIAO Xianbo; DIAO Hongwei; KONG Guanglin; ZENG Xiangbo; XU Yanyue

    2004-01-01

    Hydrogenated amorphous silicon-carbon (a-SiC:H) films were deposited by plasma enhanced chemical vapor deposition (PECVD) with a fixed methane to silane ratio ([CH4]/[SiH4]) of 1.2 and a wide range of hydrogen dilution (RH=[H2]/[SiH4 + CH4]) values of 12, 22, 33, 102 and 135. The impacts of RH on the structural and optical properties of the films were investigated by using UV-VIS transmission, Fourier transform infrared (FTIR) absorption, Raman scattering and photoluminescence (PL) measur- ements. The effects of high temperature annealing on the films were also probed. It is found that with increasing hydrogen dilution, the optical band gap increases, and the PL peak blueshifts from ~1.43 to 1.62 Ev. In annealed state, the room temperature PL peak for the low RH samples disappears, while the PL peak for the high RH samples appears at ~2.08 Ev, which is attributed to nanocrystalline Si particles confined by Si-C and Si-O bonds.

  4. The formation, properties and impact of secondary organic aerosol: current and emerging issues

    Directory of Open Access Journals (Sweden)

    J. Wildt

    2009-07-01

    Full Text Available Secondary organic aerosol (SOA accounts for a significant fraction of ambient tropospheric aerosol and a detailed knowledge of the formation, properties and transformation of SOA is therefore required to evaluate its impact on atmospheric processes, climate and human health. The chemical and physical processes associated with SOA formation are complex and varied, and, despite considerable progress in recent years, a quantitative and predictive understanding of SOA formation does not exist and therefore represents a major research challenge in atmospheric science. This review begins with an update on the current state of knowledge on the global SOA budget and is followed by an overview of the atmospheric degradation mechanisms for SOA precursors, gas-particle partitioning theory and the analytical techniques used to determine the chemical composition of SOA. A survey of recent laboratory, field and modeling studies is also presented. The following topical and emerging issues are highlighted and discussed in detail: molecular characterization of biogenic SOA constituents, condensed phase reactions and oligomerization, the interaction of atmospheric organic components with sulfuric acid, the chemical and photochemical processing of organics in the atmospheric aqueous phase, aerosol formation from real plant emissions, interaction of atmospheric organic components with water, thermodynamics and mixtures in atmospheric models. Finally, the major challenges ahead in laboratory, field and modeling studies of SOA are discussed and recommendations for future research directions are proposed.

  5. 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.

  6. Effect of Thermal Aging on Microstructure and Mechanical Properties of China Low-Activation Martensitic Steel at 550 °C

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2016-04-01

    Full Text Available The thermal aging effects on mechanical properties and microstructures in China low-activation martensitic steel have been tested by aging at 550 °C for 2,000 hours, 4,000 hours, and 10,000 hours. The microstructure was analyzed by scanning and transmission electron microscopy. The results showed that the grain size and martensitic lath increased by about 4 μm and 0.3 μm, respectively, after thermal exposure at 550 °C for 10,000 hours. MX type particles such as TaC precipitated on the matrix and Laves-phase was found on the martensitic lath boundary and grain boundary on aged specimens. The mechanical properties were investigated with tensile and Charpy impact tests. Tensile properties were not seriously affected by aging. Neither yield strength nor ultimate tensile strength changed significantly. However, the ductile–brittle transition temperature of China low-activation martensitic steel increased by 46 °C after aging for 10,000 hours due to precipitation and grain coarsening.

  7. Impact behaviour of nylon-rubber blends: 5. Influence of the mechanical properties of the elastomer

    NARCIS (Netherlands)

    Borggreve, R.J.M.; Gaymans, R.J.; Schuijer, J.

    1989-01-01

    Blends of 90wt% nylon-6 and 10wt% impact modifier were prepared. As impact modifiers were used: EPDM (ethylene propylene diene monomer) rubber, EPM (ethylene propylene monomer) rubber, polyethylene, four poly(ether esters) and some commercial impact modifers. EPDM, EPM and polyethylene were function

  8. Aerosol Impacts on Microphysical and Radiative Properties of Stratocumulus Clouds in the Southeast Pacific

    Science.gov (United States)

    Twohy, C. H.; Toohey, D. W.; Andrejczuk, M.; Anderson, J. R.; Adams, A.; Lytle, M.; George, R.; Wood, R.; Zuidema, P.; Leon, D.

    2011-12-01

    The southeast Pacific Ocean is covered by the world's largest stratocumulus cloud layer, which has a strong impact on ocean temperatures and climate in the region. The effect of anthropogenic sources of aerosol particles was investigated during the VOCALS field experiment. Aerosol measurements below and above cloud were made with a ultra-high sensitivity aerosol spectrometer and analytical electron microscopy. In addition to more standard in-cloud measurements, cloud droplets were collected and evaporated using a counterflow virtual impactor (CVI), and the non-volatile residual particles were analyzed. Many flights focused on the gradient in cloud properties along an E-W track from near the Chilean coast to remote areas offshore. Mean statistics from seven flights were compiled. Consistent with a continental source of cloud condensation nuclei, below-cloud accumulation-mode aerosol and droplet number concentration generally decreased from near shore to offshore. The effect extends ~800 to 1000 km from shore. The additional particles are mainly sulfates from anthropogenic sources. Liquid water content and drizzle concentration tended to increase with distance from shore, but exhibited much greater variability. Analysis of the droplet residual measurements showed that not only were there more residual nuclei near shore, but that they tended to be larger than those offshore. Single particle analysis over a broad particle size range was used to reveal types and sources of CCN, which were primarily sulfates near shore. Differences in the size distribution of droplet residual particles and ambient aerosol particles were observed due to the preferential activation of large aerosol particles. By progressively excluding small droplets from the CVI sample, we were able to show that the larger drops, which initiate drizzle, contain the largest aerosol particles. However, the scavenging efficiency is not sharp as expected from a simple parcel activation model. A wide range of

  9. Properties enhancement of Al-Zn-Mg alloy by retrogression and re-aging heat treatment

    Directory of Open Access Journals (Sweden)

    Zaid H.R.

    2011-01-01

    Full Text Available The higher strength 7xxx aluminum alloys exhibited low resistance to stress corrosion cracking (SCC when aged to the peak hardness (T6 temper. The overaged alloys (T7 temper developed to enhance the SCC with loss in the strength of the alloy. Recently, retrogression and re-aging (RRA heat treatments are used for improving the SCC behavior for alloys in T6 tempers such as 7075, 7475 and 8090. In this study, an application of retrogression and re-aging heat treatment processes are carried out to enhance toughness properties of the 7079-T651 aluminum alloy, while maintaining the higher strength of T651-temper. The results of charpy impact energy and electrical conductivity tests show a significantly increases in absorbed energy and electrical conductivity values, when the alloys are exposed to various retrogression temperatures (190, 200, 210°C and times (20, 40, 60 minutes, and then re-aged at 160°C for 18 hours.

  10. Microstructure property analysis of HFIR-irradiated reduced-activation ferritic/martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Tanigawa, H. E-mail: tanigawa@popsvr.tokai.jaeri.go.jp; Hashimoto, N.; Sakasegawa, H.; Klueh, R.L.; Sokolov, M.A.; Shiba, K.; Jitsukawa, S.; Kohyama, A

    2004-08-01

    The effects of irradiation on the Charpy impact properties of reduced-activation ferritic/martensitic steels were investigated on a microstructural basis. It was previously reported that the ductile-brittle transition temperature (DBTT) of F82H-IEA and its heat treatment variant increased by about 130 K after irradiation at 573 K up to 5 dpa. Moreover, the shifts in ORNL9Cr-2WVTa and JLF-1 steels were much smaller, and the differences could not be interpreted as an effect of irradiation hardening. The precipitation behavior of the irradiated steels was examined by weight analysis and X-ray diffraction analysis on extraction residues, and SEM/EDS analysis was performed on extraction replica samples and fracture surfaces. These analyses suggested that the difference in the extent of DBTT shift could be explained by (1) smaller irradiation hardening at low test temperatures caused by irradiation-induced lath structure recovery (in JLF-1), and (2) the fracture stress increase caused by the irradiation-induced over-solution of Ta (in ORNL9Cr-2WVTa)

  11. Complexation of buffer constituents with neutral complexation agents: part I. Impact on common buffer properties.

    Science.gov (United States)

    Riesová, Martina; Svobodová, Jana; Tošner, Zdeněk; Beneš, Martin; Tesařová, Eva; Gaš, Bohuslav

    2013-09-17

    The complexation of buffer constituents with the complexation agent present in the solution can very significantly influence the buffer properties, such as pH, ionic strength, or conductivity. These parameters are often crucial for selection of the separation conditions in capillary electrophoresis or high-pressure liquid chromatography (HPLC) and can significantly affect results of separation, particularly for capillary electrophoresis as shown in Part II of this paper series (Beneš, M.; Riesová, M.; Svobodová, J.; Tesařová, E.; Dubský, P.; Gaš, B. Anal. Chem. 2013, DOI: 10.1021/ac401381d). In this paper, the impact of complexation of buffer constituents with a neutral complexation agent is demonstrated theoretically as well as experimentally for the model buffer system composed of benzoic acid/LiOH or common buffers (e.g., CHES/LiOH, TAPS/LiOH, Tricine/LiOH, MOPS/LiOH, MES/LiOH, and acetic acid/LiOH). Cyclodextrins as common chiral selectors were used as model complexation agents. We were not only able to demonstrate substantial changes of pH but also to predict the general complexation characteristics of selected compounds. Because of the zwitterion character of the common buffer constituents, their charged forms complex stronger with cyclodextrins than the neutral ones do. This was fully proven by NMR measurements. Additionally complexation constants of both forms of selected compounds were determined by NMR and affinity capillary electrophoresis with a very good agreement of obtained values. These data were advantageously used for the theoretical descriptions of variations in pH, depending on the composition and concentration of the buffer. Theoretical predictions were shown to be a useful tool for deriving some general rules and laws for complexing systems.

  12. Impact of controlled particle size nanofillers on the mechanical properties of segmented polyurethane nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Finnigan, Bradley; Casey, Phil; Cookson, David; Halley, Peter; Jack, Kevin; Truss, Rowan; Martin, Darren (Queensland); (UC)

    2008-04-02

    The impact of average layered silicate particle size on the mechanical properties of thermoplastic polyurethane (TPU) nanocomposites has been investigated. At fixed addition levels (3 wt% organosilicate), an increase in average particle size resulted in an increase in stiffness. Negligible stiffening was observed for the smallest particles (30 nm) due to reduced long-range intercalation and molecular confinement, as well as ineffective stress transfer from matrix to filler. At low strain ({le}100%), an increase in filler particle size was associated with an increase in the rate of stress relaxation, tensile hysteresis, and permanent set. At high strain (1200%), two coexisting relaxation processes were observed. The rate of the slower (long-term) relaxation process, which is believed to primarily involve the hard segment rich structures, decreased on addition of particles with an average diameter of 200 nm or less. At high strain the tensile hysteresis was less sensitive to particle size, however the addition of particles with an average size of 200 nm or more caused a significant increase in permanent set. This was attributed to slippage of temporary bonds at the polymer-filler interface, and to the formation of voids at the sites of unaligned tactoids. Relative to the host TPU, the addition of particles with an average size of 30 nm caused a reduction in permanent set. This is a significant result because the addition of fillers to elastomers has long been associated with an increase in hysteresis and permanent set. At high strain, well dispersed and aligned layered silicates with relatively small interparticle distances and favourable surface interactions are capable of imparting a resistance to molecular slippage throughout the TPU matrix.

  13. Impact of pressure on transport properties of AlGaN/GaN high electron mobility transistor

    Science.gov (United States)

    Wang, Xinbo; Ji, Dong; Lu, Yanwu

    2015-11-01

    The properties of AlxGa1-xN/GaN high electron mobility transistor (HEMT) impacted by pressure are characterized quantitatively. The results indicate that the dislocation density increases as the critical thickness decreases with increasing pressure. The two-dimensional electron gas density was found to be linearly changeable with the pressure. A simulation has been completed to verify the influence of electron mobility. The results show that the misfit dislocation scattering induced by the pressure is a major limiting factor for the properties of HEMT.

  14. Statistical Assessment of the Impact of Elevated Contents of Cu and Ni on the Properties of Austempered Ductile Iron

    Directory of Open Access Journals (Sweden)

    Nawrocki P.

    2016-12-01

    Full Text Available The article presents a statistical analysis of data collected from the observation of the production of austempered ductile iron. The impact assessment of the chemical composition, i.e. high contents of Cu and Ni on the properties of ductile iron isothermal tempered is critical to find the right chemical composition of austempered ductile iron. Based on the analyses range of the percentage of Cu and Ni which were selected in the cast iron to obtain material with high strength properties.

  15. Impact of the monetary crisis on statistical properties of the Jakarta and Kuala Lumpur stock exchange indices

    Science.gov (United States)

    Mart, T.; Aminoto, T.

    2007-01-01

    Using the tools developed for statistical physics, we simultaneously analyze statistical properties of the Jakarta and Kuala Lumpur Stock Exchange indices. In spite of the small number of the data used in the analysis, the result still shows the universal behavior of complex systems previously found in the leading stock indices. We also analyze their properties before and after the crash caused by the monetary crisis. To locate the time position when the crash started we use the Omori law. We found that after the crash both stocks do not show a same statistical behavior. The impact of currency controls is observed in the distribution of the index returns.

  16. Impact of Industrial Grade Modified PVA to Vinyl Acetate Semi-continuous Emulsion Polymerization and Properties of Final Product

    Directory of Open Access Journals (Sweden)

    Mindaugas DUBININKAS

    2013-03-01

    Full Text Available Successful vinyl acetate radical emulsion polymerization in water with different type of industrial grade poly(vinyl alcohol were produced by semi continuous way. The poly(vinyl alcohol type has crucial impact on dispersion rheological as well on films and bonding strength properties. It should be stated that the films containing modified poly (vinyl alcohol has better water resistance and mechanical properties. Poly(vinyl alcohol with higher ethylene moieties content and high hydrolization degree determines extremely low viscosity of final dispersion.DOI: http://dx.doi.org/10.5755/j01.ms.19.1.3823

  17. 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.

  18. Influence of titanium diboride reinforcements on the microstructure, mechanical properties and fracture behavior of cast zinc-aluminum composites

    Science.gov (United States)

    Dionne, Sylvie

    The objective of the present study was to examine the relationships between the microstructure, mechanical properties and failure mechanisms which control the performance of TiB2 particle reinforced Zn-8 wt.% Al (ZA-8) composites. Unreinforced ZA-8 and four composite heats with nominal particle contents of 5, 10, 20 and 30 vol.% were prepared using stir casting and permanent mold casting techniques. Tensile, compression, Charpy impact and short bar chevron-notch fracture toughness tests were conducted at room temperature. The microstructure and fracture surfaces of the specimens were characterized using optical, scanning electron, transmission electron and focused ion beam microscopy. These experimental results were compared with relevant MMC models and with published data on Zn-based composites. The TiB2/ZA-8 composites had a homogeneous distribution of particles in a matrix similar to unreinforced ZA-8. The matrix grain size decreased as the TiB2 content increased. No interfacial reaction products were detected. A good correlation was obtained between the measured composite stiffness and the values predicted using an Eshelby model. The yield strength and work hardening rate of TiB2/ZA-8 were only marginally higher than those of unreinforced ZA-8. The strength properties did not increase with the particle content as predicted by the Eshelby model. The premature activation of relaxation processes limited the extent to which particle reinforcement improved the strength of the ZA-8 matrix. Temperature-activated relaxation processes such as diffusion and dislocation motion can occur readily in ZA-8 at room temperature, which corresponds to 0.44 TM. Particle reinforcement of the ZA-8 alloy produced a degradation of the toughness which was sensitive to the loading rate. The Charpy energy of TiB 2/ZA-8 was up to 85% smaller than that of ZA-8, while the corresponding loss in fracture toughness was only 15%. The moderate fracture toughness decrease was explained by the

  19. The Impact of Subway Lines on Residential Property Values in Tianjin: An Empirical Study Based on Hedonic Pricing Model

    Directory of Open Access Journals (Sweden)

    Hui Sun

    2016-01-01

    Full Text Available The construction of subways has an external impact on the urban environment. Among them, the most important acceleration function lies in the property values of housing near subway stations. Tianjin, the largest open coastal city in Northern China, is selected as the subject of the research in this paper by virtue of its unique background. The Hedonic Pricing Model is used in analysing the change in the value of the properties located within 1,000 metres of completed subway line 3 stations. Using the theories of land rent and land location, and a model of the impact of urban traffic on the surrounding real estate prices, we analyse the sphere of influence of Tianjin Metro Line 3 on real estate prices. Finally, the paper stresses the importance of urban construction and subway building and finds that different development strategies should be used according to the characteristics of the subway in various regions of the city.

  20. Effect of Welding Processes and Consumables on Tensile and Impact Properties of High Strength Quenched and Tempered Steel Joints

    Institute of Scientific and Technical Information of China (English)

    G Magudeeswaran; V Balasubramanian; G Madhusudhan Reddy; T S Balasubramanian

    2008-01-01

    Quenched and tempered steels are prone to hydrogen induced cracking in the heat affected gone after welding.The use of austenitic stainless steel consumables to weld the above steel was the only available remedy because of higher solubility for hydrogen in austenitic phase.In this investigation,an attempt was made to determine a suitable consumable to replace expensive austenitic consumables.Two different consumables,namely,austenitic stainless steel and lOW hydrogen ferritic steel,were used to fabricate the joints by shielded metal arc welding(SMAW)and flux cored arc welding(FCAW)processes.The joints fabricated by using low hydrogen ferritic steel consumables showed superior transverse tensile properties,whereas joints fabricated by using austenitic stainless steel consumables exhibited better impact toughness,irrespective of the welding process used.The SMAW joints exhibited superior mechanical and impact properties,irrespective of the consumables used,than their FCAW counterparts.

  1. Supplemental Information For: Asymmetric Distribution of Lunar Impact Basins Caused by Variations in Target Properties

    Science.gov (United States)

    Miljkovic, Katarina; Wieczorek, Mark; Collins, Gareth S.; Laneuville, Matthieu; Neumann, Gregory A.; Melosh, H. Jay; Solomon, Sean C.; Phillips, Roger J.; Smith, David E.; Zuber, Maria T.

    2014-01-01

    Maps of crustal thickness derived from NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission revealed more large impact basins on the nearside hemisphere of the Moon than on its farside. The enrichment in heat-producing elements and prolonged volcanic activity on the lunar nearside hemisphere indicate that the temperature of the nearside crust and uppermantle was hotter than that of the farside at the time of basin formation. Using the iSALE-2D hydrocode to model impact basin formation, we found that impacts on the hotter nearside would have formed basins up to two times larger than similar impacts on the cooler farside hemisphere. The size distribution of lunar impact basins is thus not representative of the earliest inner Solar system impact bombardment

  2. Asymmetric Distribution of Lunar Impact Basins Caused by Variations in Target Properties

    Science.gov (United States)

    Miljkovic, Katarina; Wieczorek, Mark A.; Collins, Gareth S.; Laneuville, Matthieu; Neumann, Gregory A.; Melosh, H. Jay; Solomon, Sean C.; Phillips, Roger J.; Smith, David E.; Zuber, Maria T.

    2014-01-01

    Maps of crustal thickness derived from NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission revealed more large impact basins on the nearside hemisphere of the Moon than on its farside. The enrichment in heat-producing elements and prolonged volcanic activity on the lunar nearside hemisphere indicate that the temperature of the nearside crust and upper mantle was hotter than that of the farside at the time of basin formation. Using the iSALE-2D hydrocode to model impact basin formation, we found that impacts on the hotter nearside would have formed basins up to two times larger than similar impacts on the cooler farside hemisphere. The size distribution of lunar impact basins is thus not representative of the earliest inner Solar system impact bombardment.

  3. Impact of implantation on the properties of N 2O-nitrided oxides of p +- and n +-gate MOS devices

    Science.gov (United States)

    Naumova, O. V.; Fomin, B. I.; Sakharova, N. V.; Ilnitsky, M. A.; Popov, V. P.

    2009-05-01

    The impact of the gate implantation on properties of N2O-nitrided thermal oxides MOS dielectric layers were evaluated in this study via current-voltage, j-ramp and current-temperature techniques. The data obtained show that implantation with boron of poly-Si gates can result in generation of border traps in oxides. The energy position of traps generated in the oxides after Fowler-Nordheim voltage stress and after hard breakdown treatments were evaluated.

  4. Impact of Anti-tacking Agents on Properties of Gas-Entrapped Membrane and Effervescent Floating Tablets

    OpenAIRE

    2014-01-01

    Tackiness caused by the gas-entrapped membrane (Eudragit®RL 30D) was usually observed during storage of the effervescent floating tablets, leading to failure in floatation and sustained release. In this work, common anti-tacking agents (glyceryl monostearate (GMS) and talc) were used to solve this tackiness problem. The impact of anti-tacking agent on the properties of free films and corresponding floating tablets was investigated. GMS was more effective than talc in reducing tackiness of the...

  5. Solid beef cattle manure application impacts on soil properties and 17β-estradiol fate in a clay loam soil.

    Science.gov (United States)

    Caron, Emmanuelle; Farenhorst, Annemieke; Hao, Xiying; Sheedy, Claudia

    2012-01-01

    Livestock manure applied to agricultural land is one of the ways natural steroid estrogens enter soils. To examine the impact of long-term solid beef cattle (Bos Taurus) manure on soil properties and 17β-estradiol sorption and mineralization, this study utilized a soil that had received beef cattle manure over 35 years. The 17β-estradiol was strongly sorbed and sorption significantly increased (P applied.

  6. Tensile strength and impact resistance properties of materials used in prosthetic check sockets, copolymer sockets, and definitive laminated sockets

    Directory of Open Access Journals (Sweden)

    Maria J. Gerschutz, PhD

    2011-10-01

    Full Text Available Prosthetic sockets serve as the interface between people with amputations and their prostheses. Although most materials used to make prosthetic sockets have been used for many years, knowledge of these materials' properties is limited, especially after they are subjected to fabrication processes. This study evaluated tensile and impact properties of the current state-of-the-art materials used to fabricate prosthetic check sockets, copolymer sockets, and definitive laminated sockets. Thermolyn Rigid and Orfitrans Stiff check socket materials produced significantly lower tensile strength and impact resistance than polyethylene terephthalate glycol (PETG. Copolymer socket materials exhibited greater resistance to impact forces than the check socket materials but lower tensile strengths than PETG. The heated molding processes, for the check socket and copolymer materials, reduced both tensile strength and elongation at break. Definitive laminated sockets were sorted according to fabrication techniques. Nyglass material had significantly higher elongation, indicating a more ductile material than carbon-based laminations. Carbon sockets with pigmented resin had higher tensile strength and modulus at break than nonpigmented carbon sockets. Elongation at yield and elongation at break were similar for both types of carbon-based laminations. The material properties determined in this study provide a foundation for understanding and improving the quality of prosthetic sockets using current fabrication materials and a basis for evaluating future technologies.

  7. Recovery of soil physical properties and microbiology in foresty drained peatlands from the impact of forest machinery

    Science.gov (United States)

    Lepilin, Dmitrii; Kimura, Bryn; Uusitalo, Jori; Laiho, Raija; Fritze, Hannu; Lauren, Ari; Tuittila, Eeva-Stiina

    2016-04-01

    Forestry-drained peatlands occupy approximately 5.7 million ha and represent almost one fourth of the total forest surface in Finland. They are subjected to the same silvicultural harvesting operations as upland forests. However, although the potential of timber harvesting to cause detrimental effects on soil is well documented in upland forests, the knowledge on environmental impact of harvesting machinery on peat soils is still lacking. To assess the impact of harvesting machines on peat physical properties and biology we collected soil samples from six peatland forests that were harvested by commonly employed Harvester and Forwarder. Samples were taken from trails formed by harvesting machinery (treatment plots) and outside of trails (control plots unaffected by machinery traffic) to a depth of 15 cm. To adders the recovery of soil properties after disturbance we sampled sites that form a chronosequence in respect to time since harvesting: 1 month (class I), 3-4 years (class II) and 14-15 years (class III). The physical and microbiological properties of soil samples were analyzed in laboratory. Harvesting operations with heavy machinery appeared to significantly increase the bulk density of peat in the machines' trails at recently harvested sites in comparison to control plots. Following change in bulk density there was change of pore size distribution with decreasing macrospores quantity. This led to slight decrease of total porosity and decrease of air filled porosity. Water retention capacity increased with increasing bulk density. CO2 evolution increased in the trails of class I site with where dissolved organic carbon concurrently decreased. While there was not impact of harvesting on microbial biomass or carbon, PLFA analysis indicated that machinery traffic caused a shift in microbial community structure. Results of class II and class III sites showed a recovery of physical properties within 16 years: treatment plots and control plots started to resemble

  8. Friction welding of a nickel free high nitrogen steel: influence of forge force on microstructure, mechanical properties and pitting corrosion resistance

    Directory of Open Access Journals (Sweden)

    Mrityunjoy Hazra

    2014-01-01

    Full Text Available In the present work, nickel free high nitrogen austenitic stainless steel specimens were joined by continuous drive friction welding process by varying the amount of forge (upsetting force and keeping other friction welding parameters such as friction force, burn-off, upset time and speed of rotation as constant at appropriate levels. The joint characterization studies include microstructural examination and evaluation of mechanical (micro-hardness, impact toughness and tensile and pitting corrosion behaviour. The integrity of the joint, as determined by the optical microscopy was very high and no crack and area of incomplete bonding were observed. Welds exhibited poor Charpy impact toughness than the parent material. Toughness for friction weld specimens decreased with increase in forge force. The tensile properties of all the welds were almost the same (irrespective of the value of the applied forge force and inferior to those of the parent material. The joints failed in the weld region for all the weld specimens. Weldments exhibited lower pitting corrosion resistance than the parent material and the corrosion resistance of the weld specimens was found to decrease with increase in forge force.

  9. JV Task 117 - Impact of Lignite Properties on Powerspan's NOx Oxidation System

    Energy Technology Data Exchange (ETDEWEB)

    Scott Tolbert; Steven Benson

    2008-02-29

    Powerspan's multipollutant control process called electrocatalytic oxidation (ECO) technology is designed to simultaneously remove SO{sub 2}, NO{sub x}, PM{sub 2.5}, acid gases (such as hydrogen fluoride [HF], hydrochloric acid [HCl], and sulfur trioxide [SO{sub 3}]), Hg, and other metals from the flue gas of coal-fired power plants. The core of this technology is a dielectric barrier discharge reactor composed of cylindrical quartz electrodes residing in metal tubes. Electrical discharge through the flue gas, passing between the electrode and the tube, produces reactive O and OH radicals. The O and OH radicals react with flue gas components to oxidize NO to NO{sub 2} and HNO{sub 3} and a small portion of the SO{sub 2} to SO{sub 3} and H{sub 2}SO{sub 4}. The oxidized compounds are subsequently removed in a downstream scrubber and wet electrostatic precipitator. A challenging characteristic of selected North Dakota lignites is their high sodium content. During high-sodium lignite combustion and gas cooling, the sodium vaporizes and condenses to produce sodium- and sulfur-rich aerosols. Based on past work, it was hypothesized that the sodium aerosols would deposit on and react with the silica electrodes and react with the silica electrodes, resulting in the formation of sodium silicate. The deposit and reacted surface layer would then electrically alter the electrode, thus impacting its dielectric properties and NO{sub x} conversion capability. The purpose of this project was to determine the impact of lignite-derived flue gas containing sodium aerosols on Powerspan's dielectric barrier discharge (DBD) reactor with specific focus on the interaction with the quartz electrodes. Partners in the project were Minnkota Power Cooperative; Basin Electric Power Cooperative; Montana Dakota Utilities Co.; Minnesota Power; the North Dakota Industrial Commission, the Lignite Energy Council, and the Lignite Research Council; the Energy & Environmental Research Center

  10. Tailoring oxide properties: An impact on adsorption characteristics of molecules and metals

    Science.gov (United States)

    Honkala, Karoliina

    2014-12-01

    Both density functional theory calculations and numerous experimental studies demonstrate a variety of unique features in metal supported oxide films and transition metal doped simple oxides, which are markedly different from their unmodified counterparts. This review highlights, from the computational perspective, recent literature on the properties of the above mentioned surfaces and how they adsorb and activate different species, support metal aggregates, and even catalyse reactions. The adsorption of Au atoms and clusters on metal-supported MgO films are reviewed together with the cluster's theoretically predicted ability to activate and dissociate O2 at the Au-MgO(100)/Ag(100) interface, as well as the impact of an interface vacancy to the binding of an Au atom. In contrast to a bulk MgO surface, an Au atom binds strongly on a metal-supported ultra-thin MgO film and becomes negatively charged. Similarly, Au clusters bind strongly on a supported MgO(100) film and are negatively charged favouring 2D planar structures. The adsorption of other metal atoms is briefly considered and compared to that of Au. Existing computational literature of adsorption and reactivity of simple molecules including O2, CO, NO2, and H2O on mainly metal-supported MgO(100) films is discussed. Chemical reactions such as CO oxidation and O2 dissociation are discussed on the bare thin MgO film and on selected Au clusters supported on MgO(100)/metal surfaces. The Au atoms at the perimeter of the cluster are responsible for catalytic activity and calculations predict that they facilitate dissociative adsorption of oxygen even at ambient conditions. The interaction of H2O with a flat and stepped Ag-supported MgO film is summarized and compared to bulk MgO. The computational results highlight spontaneous dissociation on MgO steps. Furthermore, the impact of water coverage on adsorption and dissociation is addressed. The modifications, such as oxygen vacancies and dopants, at the oxide

  11. Impact of Friedel oscillations on vapor-liquid equilibria and supercritical properties in two and three dimensions

    Science.gov (United States)

    Desgranges, Caroline; Huber, Landon; Delhommelle, Jerome

    2016-07-01

    We determine the impact of the Friedel oscillations on the phase behavior, critical properties, and thermodynamic contours in films [two dimensions (2 D )] and bulk phases [three dimensions (3 D )]. Using expanded Wang-Landau simulations, we calculate the grand-canonical partition function and, in turn, the thermodynamic properties of systems modeled with a linear combination of the Lennard-Jones and Dzugutov potentials, weighted by a parameter X (0 X X allows us to control the height of the first Friedel oscillation and to provide a complete characterization of the effect of the metal-like character in the potential on the thermodynamic properties over a wide range of conditions. For 3 D systems, we are able to show that the critical parameters exhibit a linear dependence on X and that the loci for the thermodynamic state points, for which the system shows the same compressibility factor or enthalpy as an ideal gas, are two straight lines spanning the subcritical and supercritical regions of the phase diagram for all X values. Reducing the dimensionality to 2 D results in a loss of impact of the Friedel oscillation on the critical properties, as evidenced by the virtually constant critical density across the range of X values. Furthermore, our results establish that the straightness of the two ideality lines is retained in 2 D and is independent from the height of the first Friedel oscillation in the potential.

  12. Multi-walled carbon nanotube filled polypropylene nanocomposites based on masterbatch route: Improvement of dispersion and mechanical properties through PP-g-MA addition

    Directory of Open Access Journals (Sweden)

    2008-10-01

    Full Text Available Multi-wall carbon nanotubes (MWNTs filled polypropylene (PP nanocomposites were prepared through diluting a PP/MWNT masterbatch in a PP matrix by melt compounding with a twin screw extruder. Polypropylene grafted maleic anhydride (PP-g-MA was used to promote the carbon nanotubes dispersion. The effect of PP-g-MA addition on the rheological, mechanical and morphological properties of the nanocomposites was assessed for different MWNTs loadings. Scanning electron microscopy (SEM has shown that nanotubes are distributed reasonably uniformly. A better dispersion and good adhesion between the nanotubes and the PP matrix is caused by wrapping of PP-g-MA on MWNTs. When PP-g-MA is added, dynamic moduli and viscosity further increases compared to PP/MWNT nanocomposites. The rheological percolation threshold drops significantly. Tensile and flexural moduli and Charpy impact resistance of the nanocomposites also increases by the addition of PP-g-MA. The present study confirms that PP-g-MA is efficient to promote the dispersion of MWNTs in PP matrix and serves as an adhesive to increase their interfacial strength, hence greatly improving the rheological percolation threshold and mechanical properties of PP/MWNT nanocomposites.

  13. Impact and Use of the Asymmetric Property in Bi-directional Cooperative Relaying under Asymmetric Traffic Conditions

    Science.gov (United States)

    Saeki, Takaaki; Yamamoto, Koji; Murata, Hidekazu; Yoshida, Susumu

    Cooperative relaying (CR) is a promising technique to provide spatial diversity by combining multiple signals from source and relay stations. In the present paper, the impact and use of the asymmetric property in bi-directional CR under asymmetric traffic conditions are discussed assuming that CR involves one communication pair and one relay station in a time division duplex (TDD) system. The asymmetric property means that the average communication quality differs for each transmission direction because of the difference in signal power between the combined signals for each direction. First, numerical results show the asymmetric property of bi-directional CR. Next, in order to evaluate the impact of the asymmetric property, the optimal relay position and resource allocation are compared to those in simple multi-hop relaying, which does not have the asymmetric property. Numerical results show that, in order to maximize the overall quality of bi-directional communication, the optimal relay position in CR depends on the offered traffic ratio, which is defined as the traffic ratio of each transmission direction, while the offered traffic ratio does not affect the optimal relay position in multi-hop relaying. Finally, the asymmetric property is used to enhance the overall quality. Specifically, a high overall quality can be achieved by, for example, opportunistically switching to the transmission direction with higher quality. Under asymmetric traffic conditions, weighted proportionally fair scheduling (WPFS), which is proposed in the context of downlink scheduling in a cellular network, is applied to transmission direction switching. Numerical results reveal that WPFS provides a high overall quality and that the quality ratio is similar to the offered traffic ratio.

  14. Defects in Ceramic Matrix Composites and Their Impact on Elastic Properties (Postprint)

    Science.gov (United States)

    2013-07-01

    Hammond, Elzey D. Elevated temperature mechanical properties of partially sintered alumina . Compos Sci Technol 2004;64:1551–63. [12] Hashin Z... temperatures be- low 1300 C [3], accordingly, the matrix properties were kept constant at different temperatures.Table 4 Properties of coated SiC fiber in...McMeeking RM, Zok FW. Mullite– Alumina mixtures for Use as porous matrices in oxide fiber composites. J Am Ceram Soc 2004;87(2):261–7. [8] Gowayed Y

  15. Tensile and impact properties of three-component PP/wood/elastomer composites

    Directory of Open Access Journals (Sweden)

    B. Pukanszky

    2012-03-01

    Full Text Available Polypropylene (PP was reinforced with wood flour and impact modified with elastomers to increase stiffness and impact resistance simultaneously. Elastomer content changed in four (0, 5, 10 and 20 wt%, while that of wood content in seven steps, the latter from 0 to 60 wt% in 10 wt% steps. Structure and adhesion were controlled by the addition of functionalized (maleated polymers. Composites were homogenized in a twin-screw extruder and then injection molded to tensile bars. Fracture resistance was characterized by standard and instrumented impact tests. The results showed that the components are dispersed independently of each other even when a functionalized elastomer is used for impact modification, at least under the conditions of this study. Impact resistance does not change much as a function of wood content in PP/wood composites, but decreases drastically from the very high level of the PP/elastomer blend to almost the same value obtained without impact modifier in the three-component materials. Increasing stiffness and fiber related local deformation processes led to small fracture toughness at large wood content. Micromechanical deformation processes depend mainly on the strength of PP/wood interaction; debonding and pull-out take place at poor adhesion, while fiber fracture dominates when adhesion is strong. Composites with sufficiently large impact resistance cannot be prepared in the usual range of wood contents (50–60 wt%.

  16. 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

  17. Effects of Heat Treatment on the Ballistic Impact Properties of Inconel 718 for Jet Engine Fan Containment Applications

    Science.gov (United States)

    Pereira, J. Michael; Lerch, Bradley A.

    2001-01-01

    The effects of heat treating Inconel 718 on the ballistic impact response and failure mechanisms were studied. Two different annealing conditions and an aged condition were considered. Large differences in the static properties were found between the annealed and the aged material, with the annealed condition having lower strength and hardness and greater elongation than the aged. High strain rate tests show similar results. Correspondingly large differences were found in the velocity required to penetrate material in the two conditions in impact tests involving 12.5 mm diameter, 25.4 mm long cylindrical Ti-6-4 projectiles impacting flat plates at velocities in the range of 150 to 300 m/sec. The annealed material was able to absorb over 25 percent more energy than the aged. This is contrary to results observed for ballistic impact response for higher velocity impacts typically encountered in military applications where it has been shown that there exists a correlation between target hardness and ballistic impact strength. Metallographic examination of impacted plates showed strong indication of failure due to adiabatic shear. In both materials localized bands of large shear deformation were apparent, and microhardness measurements indicated an increase in hardness in these bands compared to the surrounding material. These bands were more localized in the aged material than in the annealed material. In addition the annealed material underwent significantly greater overall deformation before failure. The results indicate that lower elongation and reduced strain hardening behavior lead to a transition from shear to adiabatic shear failure, while high elongation and better strain hardening capabilities reduce the tendency for shear to localize and result in an unstable adiabatic shear failure. This supports empirical containment design methods that relate containment thickness to the static toughness.

  18. Influence of Shielding Gas Composition on the Properties of Flux-Cored Arc Welds of Plain Carbon Steel

    Directory of Open Access Journals (Sweden)

    Ramy Gadallah

    2012-01-01

    Full Text Available In this study, the influence of variation in the shielding gas composition on the weld properties of steel ST 37-3 was investigated. Six different shielding gas compositions in addition to pure argon (Ar and pure CO2 were studied in this work using flux cored arc welding (FCAW process. For bead-on-plate (B.O.P specimens pure Ar shielding gas has excellent arc stability; however, with increase of the CO2 percent in the shielding gas compositions, the arc stability becomes noisy (unstable arc especially for pure CO2 . 75% Ar – 25% CO2 shielding gas composition has the optimum deposition rate among other shielding gases for B.O.P. Furthermore, for complete real welded joints, the absorbed energy in the Charpy impact toughness test of weld metal (W.M decreases with increase of the CO2 percent in the shielding gas composition. Additionally, the hardness of W.M decreases with the increase of the CO2 percent in the shielding gas composition.

  19. Mechanical properties of neutron-irradiated nickel-containing martensitic steels: II. Review and analysis of helium-effects studies

    Energy Technology Data Exchange (ETDEWEB)

    Klueh, R.L. [Oak Ridge National Laboratory, Metals and Ceramics Division, Building 4500S, P.O. Box 2008, MS 6151, Oak Ridge, TN 37831-6151 (United States)]. E-mail: kluehrl@ornl.gov; Hashimoto, N. [Oak Ridge National Laboratory, Metals and Ceramics Division, Building 4500S, P.O. Box 2008, MS 6151, Oak Ridge, TN 37831-6151 (United States); Sokolov, M.A. [Oak Ridge National Laboratory, Metals and Ceramics Division, Building 4500S, P.O. Box 2008, MS 6151, Oak Ridge, TN 37831-6151 (United States); Maziasz, P.J. [Oak Ridge National Laboratory, Metals and Ceramics Division, Building 4500S, P.O. Box 2008, MS 6151, Oak Ridge, TN 37831-6151 (United States); Shiba, K. [Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun, Tokai, Ibaraki 319-1195 (Japan); Jitsukawa, S. [Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun, Tokai, Ibaraki 319-1195 (Japan)

    2006-10-15

    In part I of this helium-effects study on ferritic/martensitic steels, results were presented on tensile and Charpy impact properties of 9Cr-1MoVNb (modified 9Cr-1Mo) and 12Cr-1MoVW (Sandvik HT9) steels and these steels containing 2% Ni after irradiation in the High Flux Isotope Reactor (HFIR) to 10-12 dpa at 300 and 400 deg. C and in the Fast Flux Test Facility (FFTF) to 15 dpa at 393 deg. C. The results indicated that helium caused an increment of hardening above irradiation hardening produced in the absence of helium. In addition to helium-effects studies on ferritic/martensitic steels using nickel doping, studies have also been conducted over the years using boron doping, ion implantation, and spallation neutron sources. In these previous investigations, observations of hardening and embrittlement were made that were attributed to helium. In this paper, the new results and those from previous helium-effects studies are reviewed and analyzed.

  20. THE IMPACT OF A LETTER OF MAP AMENDMENT ON FLOODPLAIN PROPERTY VALUE

    Directory of Open Access Journals (Sweden)

    James E. Larsen

    2012-01-01

    Full Text Available Substantial empirical evidence indicates properties across the United States that are located within a Special Flood Hazard Area (SFHA sell at a discount compared to similar properties otherwise located. This result is also true in our sample. Researchers have suggested the price discount equals a combination of the present value of the required flood insurance premiums and the value of uninsurable costs. To identify the portion of the discount applicable to each component, analysts have been required to estimate applicable insurance premiums and to assume a discount rate. The present paper presents a methodology that does not require these prerequisites, but still enables separation of the discount into the two components. in the united states, the federal emergency management agency sometimes issues a Letter of Map Amendment (LOMA, which exempts a property from the requirement that it be insured against flood damage as a prerequisite to the owner obtaining a federally-related mortgage loan. Therefore, any price difference between non-LOMA SFHA properties and similar properties outside the SFHA should continue to equal the sum of the two components and any significant price difference between SFHA properties with a LOMA and similar properties located outside the SFHA should equal the present value of the uninsurable costs only. Hedonic regression is used to test this proposal by comparing the selling prices of single-family house transactions for properties located within and outside the SFHA in Kettering, Ohio. In our sample, no significant uninsurable costs were detected.

  1. Uncoupling the Impact of Fracture Properties and Composition on Sensory Perception of Emulsion-Filled Gels

    NARCIS (Netherlands)

    Devezeaux de Lavergne, Marine; Strijbosch, V.M.G.; Broek, Van den A.W.M.; Velde, Van de Fred; Stieger, Markus

    2015-01-01

    The aim of the study is to investigate the effect of fracture properties and composition of emulsion-filled gels on dynamic texture perception. Twelve emulsion-filled gels varying in fracture stress (High/Low) and strain (High/Low) were prepared from three binary gel mixtures. Mechanical properti

  2. Properties of Ejecta Blanket Deposits Surrounding Morasko Meteorite Impact Craters (Poland)

    Science.gov (United States)

    Szokaluk, M.; Muszyński, A.; Jagodziński, R.; Szczuciński, W.

    2016-08-01

    Morasko impact craters are a record of the fall of a meteorite into the soft sediments. The presented results illustrate the geological structure of the area around the crater as well as providing evidence of the occurrence of ejecta blanket.

  3. Effect of Water Absorption on the Impact Properties of Carbon Fiber/ Epoxy Composites

    Institute of Scientific and Technical Information of China (English)

    LU Xiao-jun; ZHANG Qi

    2006-01-01

    In this paper, the effects of test temperatures and time on the impact damage behavior of unidirectional carbon fiber reinforced epoxy resin composites, immersed in pure water, on a pendulum impact tester, was studied. The results show that immersion in liquids has a significant effect on the impact resistance of the unidirectional composite material. It is obvious that after immersion, the mass of the material increases. The fracture initiation forces as well as the fracture initiation energy decrease as the immersion time lengthens. Moreover, the higher the temperature and the longer the time are, the more the crack propagation energy and the ductility index will be. Immersion makes the fracture mode change from the dominant fiber fracture into dominant delamination. All in all, immersion decreases the impact resistance of the composites and causes the fracture mode to change.

  4. Identifying military impacts to archaeological resources based on differences in vertical stratification of soil properties

    Science.gov (United States)

    The National Historic Preservation Act requires land-managing agencies to identify and account for their impacts on archaeological resources. Regulatory agencies that oversee compliance with historic preservation legislation frequently assume military training adversely affects archaeological resou...

  5. 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.

  6. Psychometric properties of the Brazilian version of the Early Childhood Oral Health Impact Scale (B-ECOHIS

    Directory of Open Access Journals (Sweden)

    Pordeus Isabela A

    2011-06-01

    Full Text Available Abstract Background Oral disorders can have a negative impact on the functional, social and psychological wellbeing of young children and their families and cause pain/discomfort for the child. Oral health-related quality of life (OHRQoL has emerged as an important health outcome in clinical trials and healthcare research. The Early Childhood Oral Health Impact Scale (ECOHIS is a proxy measure of children's OHRQoL designed to assess the negative impact of oral disorders on the quality of life of preschool children. The objective of this study was to evaluate the psychometric properties of the Brazilian version of the ECOHIS (B-ECOHIS. Methods This investigation was carried out in preliminary and field studies. The preliminary study comprised a cross-sectional study carried out in the city of Petropolis, Brazil. A sample of 150 children from two to five years of age was recruited at a public hospital. In the field study, an epidemiological survey was carried out in public and private preschools of Belo Horizonte, Brazil. The B-ECOHIS was answered by 1643 parents/caregivers of five-year-old male and female preschool children. In both phases, oral examinations were performed by a single previously calibrated dentist. Reliability was determined through test-retest reliability and internal consistency. Validity was determined through convergent and discriminant validities. The correlation between the scores obtained on the child and family impact sections was assessed. Results In the preliminary (P and field (F study, test-retest reliability correlation values were 0.98 and 0.99 for the child impact section and 0.97 and 0.99 for the family impact section, respectively. The B-ECOHIS demonstrated internal consistency: child impact section (P: α = 0.74; F: α = 0.80 and family impact section (P: α = 0.59; F: α = 0.76. The correlation between the scores obtained on the child and family impact sections was statistically significant (P: rs = 0.54; F: rs

  7. Impact of solid state fermentation on nutritional, physical and flavor properties of wheat bran.

    Science.gov (United States)

    Zhao, Hui-Min; Guo, Xiao-Na; Zhu, Ke-Xue

    2017-02-15

    To improve the nutritional, physical and flavor properties of wheat bran, yeast and lactic acid bacteria (LAB) were used for fermenting wheat bran in solid state. Appearance properties, nutritional properties, microstructure, hydration properties and flavor of raw bran and fermented bran were evaluated. After treatments, water extractable arabinoxylans were 3-4 times higher than in raw bran. Total dietary fiber and soluble dietary fiber increased after solid state fermentation. Over 20% of phytic acid was degraded. Microstructure changes and protein degradation were observed in fermented brans. Water holding capacity and water retention capacity of fermented brans were improved. Results suggest that solid state fermentation is an effective way to improve the properties of wheat brans.

  8. Impact of the sensory and postprandial properties of energy drinks on cognition

    OpenAIRE

    Mason, C

    2012-01-01

    The impact of energy drinks and their ingredients on cognitive functioning has been of considerable scientific interest in recent years; however studies investigating cognitive effects of energy drink consumption have centred on the postprandial impact, that is the influence of their ingredients once absorbed into the blood. It is possible however, that sensory perception of these drinks, or their ingredients can influence cognition. The four studies outlined in this thesis aim to examin...

  9. The Effect of Adding Different Types of Natural Fibers on Mechanical Properties and Impact Resistance of Concrete

    Directory of Open Access Journals (Sweden)

    Sarmed Fadhil

    2015-04-01

    Full Text Available The purpose of this study is to evaluate the effect of natural fibers: sisal and palm fibers on the different properties of concrete have been investigated through a number of tests. The properties investigated include compressive strength, flexural strength, splitting tensile strength and impact resistance of concrete. Sisal fiber has been used at three percentages of total mixture volume (0.6, 1.20 and 1.8%, respectively, while the palm fiber has been added in (2.5, 5.0 and 7.5%, respectively by volume. The results of this study show that the concrete is reinforced with sisal and palm fibers improvement in flexural strength and in splitting tensile strength while no significant alteration in the compressive strength has occurred. The results also show improvements in the impact resistance of concrete by the addition of sisal and palm fibers which give maximum increase 114.3 and 285.7%, respectively for 1.8% sisal fiber and 7.5% palm fiber, respectively. The addition of sisal and palm fibres to the plain precast concrete slabs enhances the impact resistance and compensates for the decrease in depth for (500×500×40 mm. The important visual observation is that the predominant mode of failure in all fibers which has reinforced concrete slabs is fiber pull-out. Besides, it has been figured out that the slabs remain together in one piece. They are broken; though. The plain concrete slabs have been totally disintegrated and shattered.

  10. 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

  11. Assessing changes on poly(ethylene terephthalate) properties after recycling: Mechanical recycling in laboratory versus postconsumer recycled material

    Energy Technology Data Exchange (ETDEWEB)

    López, María del Mar Castro, E-mail: quimcl02@udc.es [Grupo de Polímeros, Centro de Investigacións Tecnológicas (CIT), Departamento de Física, Escuela Universitaria Politécnica, Universidade de A Coruña, Campus de Ferrol, 15403 Ferrol (Spain); Ares Pernas, Ana Isabel, E-mail: aares@udc.es [Grupo de Polímeros, Centro de Investigacións Tecnológicas (CIT), Departamento de Física, Escuela Universitaria Politécnica, Universidade de A Coruña, Campus de Ferrol, 15403 Ferrol (Spain); Abad López, Ma José, E-mail: mjabad@udc.es [Grupo de Polímeros, Centro de Investigacións Tecnológicas (CIT), Departamento de Física, Escuela Universitaria Politécnica, Universidade de A Coruña, Campus de Ferrol, 15403 Ferrol (Spain); and others

    2014-10-15

    Keeping rheological, mechanical and thermal properties of virgin poly(ethylene terephthalate), PET, is necessary to assure the quality of second-market applications. A comparative study of these properties has been undertaken in virgin, mechanical recycled and commercial recycled PET samples. Viscoelastic characterization was carried out by rheological measurements. Mechanical properties were estimated by tensile and Charpy impact strength tests. Thermal properties and crystallinity were evaluated by differential scanning calorimetry and a deconvolution procedure was applied to study the population of the different crystals. Molecular conformational changes related to crystallinity values were studied by FTIR spectroscopy. Variations in average molecular weight were predicted from rheology. Besides, the presence-absence of linear and cyclic oligomeric species was measured by mass spectrometry techniques, as MALDI-TOF. Mechanical recycled PET undergoes a significant decline in rheological, mechanical and thermal properties upon increasing the number of reprocessing steps. This is due to the cleavage of the ester bonds with reduction in molar mass and raise in cyclic oligomeric species, in particular [GT{sub c}]{sub n} and [GT{sub c}]{sub n}-G type. Chain shortening plus enrichment in trans conformers favour the crystallization process which occurs earlier and faster with modification in crystal populations. Additional physicochemical steps are necessary to preserve the main benefits of PET. - Highlights: • Combination of multiple techniques to characterize the effects of recycling in PET. • Cleavage of ester bonds reduced viscosity, Mw, toughness in mechanical recycled PET. • Virgin, mechanical recycled and commercial recycled PET differ in crystal populations. • Cyclic oligomers [GT{sub c}]{sub n} and [GT{sub c}]{sub n}-G increase from the fourth extrusion cycle onwards.

  12. A Multiple Impact Hypothesis for Moon Formation: Target Spin and Disk Properties

    Science.gov (United States)

    Rufu, R.; Aharonson, O.

    2015-12-01

    We investigate aspects of the multiple impact hypothesis for Moon's formation, whereby the proto-Earth suffers successive collisions, each forming a debris disk that accretes to form a moonlet. The moonlets tidally advance outward, and potentially coalesce to form the Moon. In addressing the fundamental problem of the Moon's formation, we consider smaller impactors than previously studied, and investigate the effect of new geometries using a Smoothed Particles Hydrodynamics (SPH) code. For impacts within the equatorial plane, we find multiple impactors are effective in draining angular momentum from the target's initial spin due to the often-neglected angular momentum carried by escaping mass. Our simulations reveal new consequences of non-equatorial inclination of the impactor, also previously neglected. We note relationships with the resulting disks of corresponding equatorial cases, but find that the target's axis of rotation can now be tilted by a significant amount (10's of degrees) with sub-Mars size impactors. Importantly for distinguishing among competing Moon formation hypotheses, our results imply that (i) the rotational acceleration of the proto-Earth by successive impacts may be limited by angular momentum drain if the impacting population contains multiple members of medium size, and (ii) impacts onto such a non-rapidly rotation proto-Earth (well below break-up speed) can produce disks compatible with sub-Moon fragments in mass, momentum, and composition.

  13. The impact of chemical evolution on the observable properties of stellar populations

    CERN Document Server

    Tosi, M P

    2000-01-01

    The major effects of the chemical evolution of galaxies on the characteristics of their stellar populations are reviewed. A few examples of how the observed stellar properties derived from colour--magnitude diagrams can constrain chemical evolution models are given.

  14. Impact of Biofield Treatment on Chemical and Thermal Properties of Cellulose and Cellulose Acetate

    OpenAIRE

    Trivedi, Mahendra Kumar

    2015-01-01

    Cellulose being an excellent biopolymer has cemented its place firmly in many industries as a coating material, textile, composites, and biomaterial applications. In the present study, we have investigated the effect of biofield treatment on physicochemical properties of cellulose and cellulose acetate. The cellulose and cellulose acetate were exposed to biofield and further the chemical and thermal properties were investigated. X-ray diffraction study asserted that the biofield treatment did...

  15. A STUDY OF THE PROPERTIES OF CP: COEFFICIENT OF THERMAL EXPANSION, DECOMPOSITION KINETICS AND REACTION TO SPARK, FRICTION AND IMPACT

    Energy Technology Data Exchange (ETDEWEB)

    Weese, R K; Burnham, A K; Fontes, A T

    2005-03-30

    The properties of pentaamine (5-cyano-2H-tetrazolato-N2) cobalt (III) perchlorate (CP), which was first synthesized in 1968, continues to be of interest for predicting behavior in handling, shipping, aging, and thermal cook-off situations. We report coefficient of thermal expansion (CTE) values over four specific temperature ranges, decomposition kinetics using linear heating rates, and the reaction to three different types of stimuli: impact, spark, and friction. The CTE was measured using a Thermal Mechanical Analyzer (TMA) for samples that were uniaxially compressed at 10,000 psi and analyzed over a dynamic temperature range of -20 C to 70 C. Using differential scanning calorimetry, DSC, CP was decomposed at linear heating rates of 1, 3, and 7 C/min and the kinetic triplet calculated using the LLNL code Kinetics05. Values are also reported for spark, friction, and impact sensitivity.

  16. WEAR FAILURE MECHANISM AND MULTI-IMPACT PROPERTY OF AUTOMOTIVE ENGINE CHAIN

    Institute of Scientific and Technical Information of China (English)

    Meng Fanzhong; Wang Shukun; Lan Hong; Xu Rongjin; Xu Hanxue

    2005-01-01

    The multi-impact characteristics and failure mechanism of two kinds of automotive engine chain made in China are studied through engine assembly and road-drive tests. The worn surface morphologies of rubbing area between pin, bush and roller are also analyzed based on scanning electron microscope. The results show that the main wear mechanism of automotive engine chain is fatigue wear, and its failure mechanism is the forming, extending and flaking of cracks on top layer of pin and bush. In addition, the material, hot-treatment method and shaping technique for roller have a great influence upon the resistance to multi-impact. Ensuring sufficient strength and plasticity of roller, as well as adopting suitable shaping technique are the effective method to increase its resistance to multi-impact.

  17. Economic Impacts from the Boulder County, Colorado, ClimateSmart Loan Program: Using Property-Assessed Clean Energy Financing

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, M.; Cliburn, J. K.; Coughlin, J.

    2011-04-01

    This report examines the economic impacts (including job creation) from the Boulder County, Colorado, ClimateSmart Loan Program (CSLP), an example of Property-Assessed Clean Energy (PACE) financing. The CSLP was the first test of PACE financing on a multi-jurisdictional level (involving individual cities as well as the county government). It was also the first PACE program to comprehensively address energy efficiency measures and renewable energy, and it was the first funded by a public offering of both taxable and tax-exempt bonds.

  18. Correlation of Impact Conditions, Interface Reactions, Microstructural Evolution, and Mechanical Properties in Kinetic Spraying of Metals: A Review

    Science.gov (United States)

    Kim, Jaeick; Lee, Changhee

    2016-12-01

    In the past, most studies into kinetic spraying technology focused on basic research, but a large portion of current research is devoted to industrial applications of the technology. To advance, however, studies about industrial applications of kinetic spraying require profound understanding of the scientific foundations of the kinetic spray process. Nevertheless, no one has yet provided a well-organized summary of the correlations among impact conditions, interface reactions, microstructural evolution, and mechanical properties across the whole field of kinetic spraying technology. This paper provides such an overview of these correlations for kinetic spraying of metals. For each correlation, the interactions between the given conditions and the material properties of the metal feedstock powder are the most influential. These interactions are so complicated that it is difficult to systematically classify all cases into certain types. Nonetheless, we try to explain and summarize the critical factors and their roles in each relationship.

  19. Impact of thermal annealing on optical properties of vacuum evaporated CdTe thin films for solar cells

    Science.gov (United States)

    Chander, Subhash; Purohit, A.; Lal, C.; Nehra, S. P.; Dhaka, M. S.

    2016-05-01

    In this paper, the impact of thermal annealing on optical properties of cadmium telluride (CdTe) thin films is investigated. The films of thickness 650 nm were deposited on thoroughly cleaned glass substrate employing vacuum evaporation followed by thermal annealing in the temperature range 250-450 °C. The as-deposited and annealed films were characterized using UV-Vis spectrophotometer. The optical band gap is found to be decreased from 1.88 eV to 1.48 eV with thermal annealing. The refractive index is found to be in the range 2.73-2.92 and observed to increase with annealing treatment. The experimental results reveal that the thermal annealing plays an important role to enhance the optical properties of CdTe thin films and annealed films may be used as absorber layer in CdTe/CdS solar cells.

  20. The impact of lone pair-π interactions on photochromic properties in 1-D naphthalene diimide coordination networks.

    Science.gov (United States)

    Liu, Jian-Jun; Guan, Ying-Fang; Chen, Yong; Lin, Mei-Jin; Huang, Chang-Cang; Dai, Wen-Xin

    2015-10-21

    Lone pair-π interaction is an important but less studied binding force. Generally, it is too weak to influence the physical properties of supramolecular systems. Herein we reported the first example exhibiting the impact of lone pair-π interactions on photochromic properties of naphthalene diimide based coordination networks. In three isostructural 1-D networks, [(DPNDI)ZnX2] (DPNDI = N,N-di(4-pyridyl)-1,4,5,8-naphthalene diimide, X = Cl for 1, X = Br for 2 and X = I for 3), they exhibit different electron-transfer photochromic behaviors due to different lone pair-π interactions between the capped halogen atoms and electron-deficient DPNDI moieties. Specifically, 1 and 2 but not 3 are photochromic, which is attributed to a stronger lone pair-π interaction in 3 than those in 1 and 2. This study anticipates breaking a new path for designing novel photochromic materials through such unnoticeable supramolecular interactions.

  1. Correlation of Impact Conditions, Interface Reactions, Microstructural Evolution, and Mechanical Properties in Kinetic Spraying of Metals: A Review

    Science.gov (United States)

    Kim, Jaeick; Lee, Changhee

    2016-09-01

    In the past, most studies into kinetic spraying technology focused on basic research, but a large portion of current research is devoted to industrial applications of the technology. To advance, however, studies about industrial applications of kinetic spraying require profound understanding of the scientific foundations of the kinetic spray process. Nevertheless, no one has yet provided a well-organized summary of the correlations among impact conditions, interface reactions, microstructural evolution, and mechanical properties across the whole field of kinetic spraying technology. This paper provides such an overview of these correlations for kinetic spraying of metals. For each correlation, the interactions between the given conditions and the material properties of the metal feedstock powder are the most influential. These interactions are so complicated that it is difficult to systematically classify all cases into certain types. Nonetheless, we try to explain and summarize the critical factors and their roles in each relationship.

  2. Impacts of freezing and thermal treatments on dimensional and mechanical properties of wood flour-HDPE composite

    Institute of Scientific and Technical Information of China (English)

    YANG Wei-jun; XIE Yan-jun; WANG Hai-gang; LIU Bao-yu; WANG Qing-wen

    2013-01-01

    Wood plastic composite (WPC) of wood flour (WF),high density polyethylene (HDPE),maleic anhydride-grafted polyethylene (MAPE) and lubricant was prepared by extrusion,and then exposed to different temperatures to evaluate the effects of freezing and thermal treatment on its dimensional and mechanical properties.At elevated temperatures,WPC expanded rapidly initially,and then contracted slowly until reaching an equilibrium state.Treatment at 52℃ and relative humidity of 50% for 16 days improved the mechanical properties of WPC:flexure,tensile strength,and izod unnotched impact strength increased by 8%,10% and 15%,respectively.Wide-angle X-ray diffraction (XRD) tests showed that the degree of crystalization of HDPE in WPC declined with increasing treatment temperature.

  3. Soluble Dietary Fiber Fractions in Wheat Bran and Their Interactions with Wheat Gluten Have Impacts on Dough Properties.

    Science.gov (United States)

    Li, Qian; Liu, Rui; Wu, Tao; Wang, Man; Zhang, Min

    2016-11-23

    Six soluble dietary fiber (SDF) fractions were prepared via stepwise ethanol precipitation from natural and fermented wheat bran. The chemical composition, molecular weight distribution, and glycosidic linkage and substitution pattern of each SDF fraction were elucidated by sugar analysis, periodate oxidation and Smith degradation, molecular determination, and (1)H nuclear magnetic resonance (NMR) analysis. The impacts of SDF fractions on the rheological properties and morphologies of doughs were investigated by farinography, rheometry, and scanning electron microscopy (SEM) to clarify the relationship between the microstructural features of SDF fractions and the macroscopic properties of SDF-containing doughs. The interactions between SDF fractions and wheat glutens in doughs were further studied by confocal laser scanning microscopy (CLSM). The experimental results indicated that the SDF fraction with an intermediate molecular weight but a higher substitution degree and a larger disubstitution ratio was most compatible with the dough network and beneficial to dough quality.

  4. Novel slow release nanocomposite nitrogen fertilizers: the impact of polymers on nanocomposite properties and function

    Science.gov (United States)

    Efficient use of fertilizers, especially nitrogen, is essential and strategic to agricultural production. Among the technologies that can contribute to efficient use of fertilizers are slow or controlled release products. This paper describes the impact on structure, urea release rate and function i...

  5. Pilot plant assessment of blend properties and their impact on critical power plant components

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-10-01

    A series of tests were performed to determine the effects of blending eastern bituminous coals with western subbituminous coals on utility boiler operation. Relative to the baseline bituminous coal, the testing reported here indicated that there were significant impacts to boiler performance due to the blending of the eastern and western coals. Results indicated that fuel blending can be used to adequately control flue gas emissions of both SO{sub 2} and NO{sub x} at the expense of reduced milling efficiency, increased sootblowing in the high-temperature and low-temperature regions of the boiler and, to a lesser extent, decreased collection efficiency for an electrostatic precipitator. The higher reactivity of the subbituminous coal increased the overall combustion efficiency, which may tend to decrease the impact of milling efficiency losses. The extent of these impacts was directly related to the percentage of subbituminous coal in the blends. At the lowest blend ratios of subbituminous coal, the impacts were greatly reduced.

  6. Solid, shape recovered 'Bulk' nitinol: Part II-Mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Saigal, Anil, E-mail: anil.saigal@tufts.edu [Department of Mechanical Engineering, Tufts University, Medford, MA 02155 (United States); Fonte, Matthew [Department of Mechanical Engineering, Tufts University, Medford, MA 02155 (United States)

    2011-06-25

    Highlights: {yields} Evaluate use of solid bulk Nitinol as a potential material for hip replacements. {yields} At 400 MPa, Nitinol has an endurance limit greater than 10 million cycles. {yields} Below 445 MPa [1 1 1] textured specimens last longer than [1 1 0] textured specimens. {yields} Above 445 MPa, it switches and both fail relatively quickly around 400,000 cycles. {yields} Impact toughness - Charpy: 4 ft-lbs {+-} 3%, CT: 20-31 MPa{radical}m. - Abstract: The use of Nitinol for medical purposes was first reported in the late 1960s. Today Nitinol is commonly used for the manufacture of stents, which are primarily used in peripheral and coronary bypass graft interventions. The application of NiTi in orthopedics is an exciting prospect but one that has yet to be realized. Nitinol's unique mechanical behavior is derived from the coordinated atomic movements manifesting in phase transformations from cubic austenite to monoclinic martensite. These phase transformations are solid-to-solid phase transformations that occur without diffusion or plasticity, potentially making them reversible. They involve changes in the crystalline structure that can be induced by changes in either temperature or stress. In addition to phase transformations, Nitinol's mechanical strength is strongly dependent on the alloy composition and the method in which the material is processed, i.e. rolled, drawn, extruded, or forged. The mechanical work, combined with the intermediate heat treatment steps, contribute to modify microstructure, transformation temperatures and mechanical properties. These manufacturing processing steps lead to texturing (crystallographic alignment) of the material. Alignment of the atomic planes from texture in the polycrystalline material have a marked influence on the mechanical properties by either limiting or promoting phase transformations and shape recovery strains. This paper focuses on the fatigue and fracture properties of Nitinol.

  7. Spatial variability of the properties of marsh soils and their impact on vegetation

    Science.gov (United States)

    Sidorova, V. A.; Svyatova, E. N.; Tseits, M. A.

    2015-03-01

    Spatial variability of the properties of soils and the character of vegetation was studied on seacoasts of the Velikii Island in the Kandalaksha Bay of the White Sea. It was found that the chemical and physicochemical properties of marsh soils (Tidalic Fluvisols) are largely dictated by the distance from the sea and elevation of the sampling point above sea level. The spatial distribution of the soil properties is described by a quadratic trend surface. With an increase in the distance from the sea, the concentration of ions in the soil solution decreases, and the organic carbon content and soil acidity become higher. The spatial dependence of the degree of variability in the soil properties is moderate. Regular changes in the soil properties along the sea-land gradient are accompanied by the presence of specific spatial patterns related to the system of temporary water streams, huge boulders, and beached heaps of sea algae and wood debris. The cluster analysis made it possible to distinguish between five soil classes corresponding to the following plant communities: barren surface (no permanent vegetation), clayey-sandy littoral with sparse halophytes, marsh with large rhizomatous grasses, and grass-forb-bunchberry vegetation of forest margins. The subdivision into classes is especially distinct with respect to the concentration of chloride ions. The following groups of factors affect the distribution of vegetation: the composition of the soil solution, the height above sea level, the pH of water suspensions, and the humus content.

  8. The impact of hydrate saturation on the mechanical, electrical, and thermal properties of hydrate-bearing sand, silts, and clay

    Energy Technology Data Exchange (ETDEWEB)

    Santamarina, J.C. [Georgia Inst. of Technology, Atlanta, GA (United States). School of Civil and Environmental Engineering; Ruppel, C. [United States Geological Survey, Woods Hole, MA (United States)

    2008-07-01

    A study was conducted to provide an internally-consistent, systematically-acquired database that could help in evaluating gas hydrate reservoirs. Other objectives were to assist in geomechanical analyses, hazards evaluation and the development of methane hydrate production techniques in sandy lithologies and fine-grained sediments that exist in the northern Gulf of Mexico. An understanding of the physical properties of hydrate-bearing sediments facilitates the interpretation of geophysical field data, borehole and slope stability analyses, and reservoir simulation and production models. This paper reported on the key findings derived from 5 years of laboratory experiments conducted on synthetic samples of sand, silts, or clays subjected to various confining pressures. The samples contained controlled saturations of tetrahydrofuran hydrate formed from the dissolved phase. This internally-consistent data set was used to conduct a comprehensive analysis of the trends in geophysical and geotechnical properties as a function of hydrate saturation, soil characteristics, and other parameters. The experiments emphasized measurements of seismic velocities, electrical conductivity and permittivity, large strain deformation and strength, and thermal conductivity. The impact of hydrate formation technique on the resulting physical properties measurements were discussed. The data set was used to identify systematic effects of sediment characteristics, hydrate concentration, and state of stress. The study showed that the electrical properties of hydrate-bearing sediments are less sensitive to the method used to form hydrate in the laboratory than to hydrate saturation. It was concluded that mechanical properties are strongly influenced by both soil properties and the hydrate loci. Since the thermal conductivity depends on the interaction of several factors, it cannot be readily predicted by volume average formulations. 23 refs., 2 tabs., 9 figs.

  9. The impact of manufacturing process on the content of hard triglycerides, hardness and thermal properties of milk chocolate

    Directory of Open Access Journals (Sweden)

    Šoronja-Simović Dragana M.

    2012-01-01

    Full Text Available The rheological and physical properties of the chocolate mass depend on the ingredient composition as well as the manufacturing process. For the purpose of this work, a milk chocolate mass of identical composition and raw materials was manufactured by using the two different manufacturing processes: a standard manufacturing process (SM in five-roller mills including conching, and an unconventional manufacturing process in a ball mill (R1. The quality of both milk chocolate masses was examined by the comparison of thermal (differential scanning calorimetry analysis, textural properties (texture analysis, and the content of hard triglycerides (nuclear magnetic resonance spectroscopy. The main goal of this work was to determine whether chocolate can be produced in a ball mill, using the manufacturing process which results in significant savings, without causing drastic changes to the chocolate physical properties. The new manufacturing process rationalises the standard method by combining two phases, namely conching, and refining into a single one. This results in reduced initial and maintenance costs, as well as costs of workforce and fuel, etc. The results have shown that the new chocolate manufacturing process has a positive impact on texture and thermal properties, while the content of hard triglycerides remains the same.

  10. Fabrication using a levitation melting method of V-4Cr-4Ti-Si-Al-Y alloys and their mechanical properties

    Science.gov (United States)

    Chuto, Toshinori; Satou, Manabu; Hasegawa, Akira; Abe, Katsunori; Nagasaka, Takuya; Muroga, Takeo

    2002-12-01

    Reduction of interstitial impurities such as O and N is a potential method to improve various properties of vanadium alloys. It was shown that addition of Si, Al and Y was useful to reduce the oxygen concentration and to improve post-irradiation ductility at relatively low temperatures for V-Cr-Ti alloys. Several 2.5 kg alloys of V-4Cr-4Ti-Si-Al-Y type were fabricated by using a levitation melting method. Charpy impact test by an instrumented testing machine has been conducted using miniaturized specimens. Tensile tests have been carried out before and after neutron irradiation. The miniaturized specimens were irradiated up to 8×10 22 n/m 2 ( E>1 MeV) at 290 °C in Japan Materials Testing Reactor. By adopting a levitation melting method, high-purity kg-scale ingots of V-4Cr-4Ti-Si-Al-Y alloys with ˜80 ppm C, <170 ppm O and ˜110 ppm N were obtained. The V-4Cr-4Ti-0.1Si-0.1Al-0.1Y alloy fabricated in this study showed good impact properties compared with a previous laboratory-scale alloy. This alloy showed good tensile properties even after neutron irradiation at 290 °C. Levitation melting can be adopted to produce large ingots of V-Cr-Ti-Si-Al-Y type alloys by controlling the amount of yttrium addition. In this study, the technology for fabrication of high-purity kg-scale ingots of V-4Cr-4Ti-Si-Al-Y alloy has been demonstrated, and has made it possible to investigate systematically various properties of the alloy.

  11. The impact of individual nuclear properties on $r$-process nucleosynthesis

    CERN Document Server

    Mumpower, M R; McLaughlin, G C; Aprahamian, A

    2015-01-01

    The astrophysical rapid neutron capture process or `$r$ process' of nucleosynthesis is believed to be responsible for the production of approximately half the heavy element abundances found in nature. This multifaceted problem remains one of the greatest open challenges in all of physics. Knowledge of nuclear physics properties such as masses, $\\beta$-decay and neutron capture rates, as well as $\\beta$-delayed neutron emission probabilities are critical inputs that go into calculations of $r$-process nucleosynthesis. While properties of nuclei near stability have been established, much still remains unknown regarding neutron-rich nuclei far from stability that may participate in the $r$ process. Sensitivity studies gauge the astrophysical response of a change in nuclear physics input(s) which allows for the isolation of the most important nuclear properties that shape the final abundances observed in nature. This review summarizes the extent of recent sensitivity studies and highlights how these studies play ...

  12. Working fluid selection for organic Rankine cycles - Impact of uncertainty of fluid properties

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Andreasen, Jesper Graa; Liu, Wei

    2016-01-01

    of processmodels and constraints 2) selection of property models, i.e. Penge Robinson equation of state 3)screening of 1965 possible working fluid candidates including identification of optimal process parametersbased on Monte Carlo sampling 4) propagating uncertainty of fluid parameters to the ORC netpower output......This study presents a generic methodology to select working fluids for ORC (Organic Rankine Cycles)taking into account property uncertainties of the working fluids. A Monte Carlo procedure is described as a tool to propagate the influence of the input uncertainty of the fluid parameters on the ORC...

  13. Late stages of stellar evolution and their impact on spectrophotometric properties of galaxies

    CERN Document Server

    Buzzoni, Alberto

    2007-01-01

    The connection between AGB evolution of stellar populations and infrared vs. ultraviolet properties of the parent galaxies is reviewed relying on the updated lookout provided by population-synthesis theory. In particular, planetary-nebula events and hot horizontal-branch evolution are assessed in a unitary view to outline a plain general picture of galaxy spectrophotometric evolution. This will include a brief discussion of relevant phenomena such as the "UV upturn" in ellipticals and the stellar mass loss properties along the galaxy morphological sequence.

  14. Late Stages of Stellar Evolution and their Impact on Spectrophotometric Properties of Galaxies

    Science.gov (United States)

    Buzzoni, A.

    2007-12-01

    The connection between AGB evolution of stellar populations and infrared vs. ultraviolet properties of the parent galaxies is reviewed relying on the updated lookout provided by population-synthesis theory. In particular, planetary-nebula events and hot horizontal-branch evolution are assessed in a unitary view to outline a plain general picture of galaxy spectrophotometric evolution. This will include a brief discussion of relevant phenomena such as the ``UV upturn'' in ellipticals and the stellar mass loss properties along the galaxy morphological sequence.

  15. Influences of Fly Ash on Concrete Product's Properties and Environmental Impact Reduction

    Directory of Open Access Journals (Sweden)

    Thipsuree Kornboonraksa

    2015-01-01

    Full Text Available This research aimed to study effects of incorporating fly ash into concrete products. Scope of this study were (1 hazard identification of fly ash (2 study on standard testing of various concrete products and (3 study on environmental impact assessment of concrete products mixed with fly ash. Various types of fly ash namely A, B, C and D were sampling from different power plants. Hazard identification of fly ash was analyzed in terms of total threshold limit concentration (TTLC and soluble threshold limit concentration (STLC. It was found that concentrations of chromium, cadmium, lead, mercury, nickel, zinc, copper and arsenic passed the criteria of notification of the ministry of industry regarding disposal of wastes or unusable materials B.E. 2548 (2005 in appendix-2.Three types of concrete products namely brick road, concrete block and ready mixed concrete were studied. Fly ash was used as cementitious materials to replace Portland cement at 10% and 30% mixture. Concrete products with proportion of fly ash showed lower compressive strengths during 28 days of curing times. However, increase of curing times showed higher compressive strengths for all types of concrete products. ANOVA analysis showed that different fly ash proportion and curing times had a significant effect on compressive strength. The method of CML2 baseline 2000, SimaPro 7.3 was used in environmental impact assessment. The functional unit was set up through working area of 1 m3. It was found that concrete products mixed with fly ash showed lower environmental impact compared to concrete products without fly ash. Increasing proportion of fly ash showed decreased environmental impact. From ANOVA analysis, there was no significant effect of fly ash types on environmental impact reduction for all types of concrete products. However, % fly ash mixture showed significant effect on environmental impact reduction especially in terms of global warming. Decrease in global warming (GW

  16. Impact of saline water on soil properties and crop yield: a simulation study

    NARCIS (Netherlands)

    Tedeschi, A.; Barbieri, G.; Menenti, M.

    1996-01-01

    A field experiment on vegetable crops was carried out between 1988 and 1993 near Naples (Italy). The effect of saline water on soil properties was assessed by means of laboratory experiments on undisturbed soil cores. Significant differences in the soil water retention curves and unsaturated capilla

  17. Characterization of cohesion, adhesion and creep-properties of dynamically loaded coatings through the impact tester

    Energy Technology Data Exchange (ETDEWEB)

    Bouzakis, K.D.; Michailidis, N.; Lontos, A.; Siganos, A.; Hadjiyiannis, S.; Giannopoulos, G.; Maliaris, G. [Aristoteles Univ., Thessaloniki (Greece). Lab. for Machine Tools and Mfg. Engineering; Erkens, G. [CemeCon GmbH, Wuerselen (Germany)

    2001-10-01

    The coating impact test, in combination with finite elements method (FEM) simulation, is successfully used to characterize the fatigue performance of coatings. Critical values for stress components, responsible for distinctive fatigue failure modes of the coating, are obtained and the fatigue limits of various coatings are illustrated in form of generally applicable Smith and Woehler diagrams, determined through a developed evaluation software. This software takes into account the impact test experimental data, as well as coating and substrate constitutive laws. Herewith coating adhesive and cohesive failure modes are elucidated and a cutting performance prediction of coated tools can be carried out. On the other hand, creep phenomena of plasma sprayed coatings are quantitatively interpreted. (orig.)

  18. The impact of kinetic effects on the properties of relativistic electron-positron shocks

    CERN Document Server

    Stockem, A; Fonseca, R A; Silva, L O

    2012-01-01

    We assess the impact of non-thermally shock-accelerated particles on the magnetohydrodynamic (MHD) jump conditions of relativistic shocks. The adiabatic constant is calculated directly from first principle particle-in-cell simulation data, enabling a semi-kinetic approach to improve the standard fluid model and allowing for an identification of the key parameters that define the shock structure. We find that the evolving upstream parameters have a stronger impact than the corrections due to non-thermal particles. We find that the decrease of the upstream bulk speed yields deviations from the standard MHD model up to 10%. Furthermore, we obtain a quantitative definition of the shock transition region from our analysis. For Weibel-mediated shocks the inclusion of a magnetic field in the MHD conservation equations is addressed for the first time.

  19. Impact of presowing laser irradiation of seeds on sugar beet properties

    Science.gov (United States)

    Sacała, E.; Demczuk, A.; Grzyś, E.; Prośba-Białczyk, U.; Szajsner, H.

    2012-07-01

    The aim of the experiment was to establish the influence of biostimulation on the sugar beet seeds. The seeds came from the specialized breeding program energ'hill or were irradiated by the laser in two doses. The impact of the biostimulation was analyzed by determining the nitrate reductase activity and the nitrate, chlorophyll and carotenoids contents in leaves, as well as, the dry matter and sugar concentration in mature roots. The field experiment was established for two sugar beet cultivars. Biostimulation by irradiation and a special seed breeding program energ'hill had a positive influence on some examined parameters (particularly on nitrate reductase activity in Ruveta and in numerous cases on photosynthetic pigments in both cultivars). Regarding the dry matter accumulation and sugar concentration this impact was more favourable for Tiziana than for Ruveta cultivar.

  20. Impact of thermal annealing on physical properties of vacuum evaporated polycrystalline CdTe thin films for solar cell applications

    Science.gov (United States)

    Chander, Subhash; Dhaka, M. S.

    2016-06-01

    A study on impact of post-deposition thermal annealing on the physical properties of CdTe thin films is undertaken in this paper. The thin films of thickness 500 nm were grown on ITO and glass substrates employing thermal vacuum evaporation followed by post-deposition thermal annealing in air atmosphere within low temperature range 150-350 °C. These films were subjected to the XRD, UV-Vis NIR spectrophotometer, source meter, SEM coupled with EDS and AFM for structural, optical, electrical and surface topographical analysis respectively. The diffraction patterns reveal that the films are having zinc-blende cubic structure with preferred orientation along (111) and polycrystalline in nature. The crystallographic parameters are calculated and discussed in detail. The optical band gap is found in the range 1.48-1.64 eV and observed to decrease with thermal annealing. The current-voltage characteristics show that the CdTe films exhibit linear ohmic behavior. The SEM studies show that the as-grown films are homogeneous, uniform and free from defects. The AFM studies reveal that the surface roughness of films is observed to increase with annealing. The experimental results reveal that the thermal annealing has significant impact on the physical properties of CdTe thin films and may be used as absorber layer to the CdTe/CdS thin films solar cells.

  1. Damage phenomena of thin hard coatings submitted to repeated impacts: Influence of the substrate and film properties

    Energy Technology Data Exchange (ETDEWEB)

    Lamri, S. [IRTES-LERMPS, EA 7274, UTBM, 90 010 Belfort Cedex (France); ICD-LASMIS, UTT antenne de Nogent, Rue Lavoisier, 52800 Nogent (France); Langlade, C., E-mail: cecile.langlade@utbm.fr [IRTES-LERMPS, EA 7274, UTBM, 90 010 Belfort Cedex (France); Kermouche, G. [LTDS Laboratory, UMR CNRS 5513, ENI St Etienne (France); UMR CNRS 5146, Ecole des Mines de St-Etienne, Centre SMS, 158 Cours Fauriel, 42100 St-Etienne (France)

    2013-01-10

    To evaluate the surface fatigue resistance of some thin nitride films obtained by Physical Vapour Deposition (PVD) techniques, repeated impact tests have been performed under controlled impact conditions. Short and long duration tests have revealed the occurrence of an original damage phenomenon likely linked to a mechanical blistering of the films. As these blisters appear to be the first damage step, their formation has to be understood in order to be avoided in industrial applications. In particular, the role of the mechanical properties of the substrate has to be clarified as thin protective coatings may be used on pieces prepared using various heat treatments. finite element method (FEM) analysis has been conducted in order to better understand the specific mechanical conditions in the substrate and at the film-substrate interface that could lead to such blistering phenomena. Correlations with the experimental results have been evidenced. From the modelling results the substrate properties have been shown to be of significant influence on the blister formation. However as they do not fully explain the origin of this phenomenon, the influence of the substrate microstructure has also been studied and the presence of vanadium carbides appears to be of major effect.

  2. Measuring workplace trauma response in Australian paramedics: an investigation into the psychometric properties of the Impact of Event Scale

    Directory of Open Access Journals (Sweden)

    Hogan N

    2015-12-01

    Full Text Available Nicola Hogan,1 Shane Costello,1 Malcolm Boyle,2 Brett Williams2 1Faculty of Education, Monash University, Clayton, VIC, Australia; 2Department of Community Emergency Health and Paramedic Practice, Monash University, Frankston, VIC, Australia Introduction: Investigation into the psychological effects of violence toward health care workers and its associated trauma is increasing. The Impact of Event Scale (IES provides a measure of current, subjective, emotional distress symptomatic of a specific traumatic event. However, its validity among paramedics is largely unknown. Problem: The purpose of this study was to investigate the psychometric properties and factor structure of the IES with a sample of Australian paramedics. Methods: The study aimed to investigate the psychometric properties and factor structure of the 15-item IES with a sample of Australian paramedics using Exploratory Factor Analysis with model fit statistics as found in confirmatory analysis. Results: Maximum Likelihood Factor Analysis with Varimax rotation supported the hypothesis that a two-factor solution would provide the best fit of the data. Procrustes rotation provided further support for this hypothesis indicating that the factors, labeled “Intrusion” and “Avoidance”, as well as the individual items of the 12-item final model, were a good fit to an ideal solution. Conclusion: The revision of the scale has improved its validity for use in the general population of paramedics, improving the potential for its use in trauma-related research. Keywords: impact of event scale, psychometrics, paramedics, occupational violence, PTSD

  3. Impact of Non-Invasively Induced Motor Deficits on Tibial Cortical Properties in Mutant Lurcher Mice.

    Directory of Open Access Journals (Sweden)

    Alena Jindrová

    Full Text Available It has been shown that Lurcher mutant mice have significantly altered motor abilities, regarding their motor coordination and muscular strength because of olivorecebellar degeneration. We assessed the response of the cross-sectional geometry and lacuno-canalicular network properties of the tibial mid-diaphyseal cortical bone to motor differences between Lurcher and wild-type (WT male mice from the B6CBA strain. The first data set used in the cross-sectional geometry analysis consists of 16 mice of 4 months of age and 32 mice of 9 months of age. The second data set used in the lacunar-canalicular network analysis consists of 10 mice of 4 months of age. We compared two cross-sectional geometry and four lacunar-canalicular properties by I-region using the maximum and minimum second moment of area and anatomical orientation as well as H-regions using histological differences within a cross section. We identified inconsistent differences in the studied cross-sectional geometry properties between Lurcher and WT mice. The biggest significant difference between Lurcher and WT mice is found in the number of canaliculi, whereas in the other studied properties are only limited. Lurcher mice exhibit an increased number of canaliculi (p < 0.01 in all studied regions compared with the WT controls. The number of canaliculi is also negatively correlated with the distance from the centroid in the Lurcher and positively correlated in the WT mice. When the Lurcher and WT sample is pooled, the number of canaliculi and lacunar volume is increased in the posterior Imax region, and in addition, midcortical H-region exhibit lower number of canaliculi, lacuna to lacuna distance and increased lacunar volume. Our results indicate, that the importance of precise sample selection within cross sections in future studies is highlighted because of the histological heterogeneity of lacunar-canalicular network properties within the I-region and H-region in the mouse cortical

  4. Martian Polar Region Impact Craters: Geometric Properties From Mars Orbiter Laser Altimeter (MOLA) Observations

    Science.gov (United States)

    Garvin, J. B.; Sakimoto, S. E. H.; Frawley, J. J.; Matias, A.

    1998-01-01

    The Mars Orbiter Laser Altimeter (MOLA) instrument onboard the Mars Global Surveyor (MGS) spacecraft has so far observed approximately 100 impact landforms in the north polar latitudes (>60 degrees N) of Mars. Correlation of the topography with Viking Orbiter images indicate that many of these are near-center profiles, and for some of the most northern craters, multiple data passes have been acquired. The northern high latitudes of Mars may contain substantial ground ice and be topped with seasonal frost (largely CO2 with some water), forming each winter. We have analyzed various diagnostic crater topologic parameters for this high-latitude crater population with the objective of characterizing impact features in north polar terrains, and we explore whether there is evidence of interaction with ground ice, frost, dune movement, or other polar processes. We find that there are substantial topographic variations from the characteristics of midlatitude craters in the polar craters that are not readily apparent from prior images. The transition from small simple craters to large complex craters is not well defined, as was observed in the midlatitude MOLA data (transition at 7-8 km). Additionally, there appear to be additional topographic complexities such as anomalously large central structures in many polar latitude impact features. It is not yet clear if these are due to target-induced differences in the formation of the crater or post-formation modifications from polar processes.

  5. Physical property data from the ICDP-USGS Eyreville cores A and B, Chesapeake Bay impact structure, Virginia, USA, acquired using a multisensor core logger

    Science.gov (United States)

    Pierce, H.A.; Murray, J.B.

    2009-01-01

    The International Continental Scientific Drilling Program (ICDP) and the U.S. Geological Survey (USGS) drilled three core holes to a composite depth of 1766 m within the moat of the Chesapeake Bay impact structure. Core recovery rates from the drilling were high (??90%), but problems with core hole collapse limited the geophysical downhole logging to natural-gamma and temperature logs. To supplement the downhole logs, ??5% of the Chesapeake Bay impact structure cores was processed through the USGS GeoTek multisensor core logger (MSCL) located in Menlo Park, California. The measured physical properties included core thickness (cm), density (g cm-3), P-wave velocity (m s-1), P-wave amplitude (%), magnetic susceptibility (cgs), and resistivity (ohm-m). Fractional porosity was a secondary calculated property. The MSCL data-sampling interval for all core sections was 1 cm longitudinally. Photos of each MSCL sampled core section were imbedded with the physical property data for direct comparison. These data have been used in seismic, geologic, thermal history, magnetic, and gravity models of the Chesapeake Bay impact structure. Each physical property curve has a unique signature when viewed over the full depth of the Chesapeake Bay impact structure core holes. Variations in the measured properties reflect differences in pre-impact target-rock lithologies and spatial variations in impact-related deformation during late-stage crater collapse and ocean resurge. ?? 2009 The Geological Society of America.

  6. Post-weld Tempered Microstructure and Mechanical Properties of Hybrid Laser-Arc Welded Cast Martensitic Stainless Steel CA6NM

    Science.gov (United States)

    Mirakhorli, Fatemeh; Cao, Xinjin; Pham, Xuan-Tan; Wanjara, Priti; Fihey, Jean-Luc

    2016-12-01

    Manufacturing of hydroelectric turbine components involves the assembly of thick-walled stainless steels using conventional multi-pass arc welding processes. By contrast, hybrid laser-arc welding may be an attractive process for assembly of such materials to realize deeper penetration depths, higher production rates, narrower fusion, and heat-affected zones, and lower distortion. In the present work, single-pass hybrid laser-arc welding of 10-mm thick CA6NM, a low carbon martensitic stainless steel, was carried out in the butt joint configuration using a continuous wave fiber laser at its maximum power of 5.2 kW over welding speeds ranging from 0.75 to 1.2 m/minute. The microstructures across the weldment were characterized after post-weld tempering at 873 K (600 °C) for 1 hour. From microscopic examinations, the fusion zone was observed to mainly consist of tempered lath martensite and some residual delta-ferrite. The mechanical properties were evaluated in the post-weld tempered condition and correlated to the microstructures and defects. The ultimate tensile strength and Charpy impact energy values of the fully penetrated welds in the tempered condition were acceptable according to ASTM, ASME, and industrial specifications, which bodes well for the introduction of hybrid laser-arc welding technology for the manufacturing of next generation hydroelectric turbine components.

  7. Analysis of the thermal comfort and impact properties of the neoprene-spacer fabric structure for preventing the joint damages

    Directory of Open Access Journals (Sweden)

    Ehsan Ghorbani

    2013-01-01

    Full Text Available Background: Frequent moves at the joint, plus external factors such as trauma, aging, and etc., are all reasons for joint damages. In order to protect and care of joints, the orthopedic textiles are used. To protect the joints, these textiles keep muscles warm to prevent shock. To produce orthopedic textiles, Neoprene foams have been traditionally used. These foams are flexible and resist impact, but are not comfortable enough and might cause problems for the consumer. This study introduces a new structure consisting of perforated Neoprene foam attached to the spacer fabric and also compares the properties of thermal and moisture comfort and impact properties of this structure in comparison with Neoprene foam. Methods: In order to measure the factors related to the samples lateral pressure behavior, a tensile tester was used. A uniform pressure is applied to the samples and a force - displacement curve is obtained. The test continues until the maximum compression force is reached to 50 N. The area under the curve is much greater; more energy is absorbed during the impact. In order to investigate the dynamic heat and moisture transfer of fabrics, an experimental apparatus was developed. This device made the simulation of sweating of human body possible and consisted of a controlled environmental chamber, sweating guarded hot plate, and data acquisition system. Results: The findings show that the Neoprene-spacer fabric structure represents higher toughness values compared to other samples (P ≤ 0.001. Neoprene-spacer fabric structure (A3 has higher rate of moisture transport than conventional Neoprene foam; because of undesirable comfort characteristics in Neoprene. Conclusions: Results of the tests indicate full advantage of the new structure compared with the Neoprene foam for use in orthopedic textiles (P ≤ 0.001.

  8. 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

  9. Ultra-high pressure homogenization-induced changes in skim milk: impact on acid coagulation properties.

    Science.gov (United States)

    Serra, Mar; Trujillo, Antonio J; Jaramillo, Pamela D; Guamis, Buenaventura; Ferragut, Victoria

    2008-02-01

    The effects of ultra-high pressure homogenization (UHPH) on skim milk yogurt making properties were investigated. UHPH-treated milk was compared with conventionally homogenised (15 MPa) heat-treated skim milk (90 degrees C for 90 s), and to skim milk treated under the same thermal conditions but fortified with 3% skim milk powder. Results of the present study showed that UHPH is capable of reducing skim milk particle size which leads to the formation of finer dispersions than those obtained by conventional homogenisation combined with heat treatment. In addition, results involving coagulation properties and yogurt characteristics reflected that, when increasing UHPH pressure conditions some parameters such as density of the gel, aggregation rate and water retention are improved.

  10. Impact Of Air Pollution On Property Values: A Hedonic Price Study

    Directory of Open Access Journals (Sweden)

    Endah Saptutyningsih

    2013-06-01

    Full Text Available The main purpose of this study is the calculation of implicit prices of the environmental level of air quality in Yogyakarta on the basis of housing property prices. By means of Geographical Information System, the housing property prices characterized from the area which have highest air pollution level in province of Yogyakarta. Carbon monoxide is used as the pollution variable. The methodological framework for estimation is based on a hedonic price model. This approach establishes a relationship between the price of a marketable good (e.g. housing and the amenities and characteristics this good contains. Therefore, if variations in air pollution levels occur, then households would change their behavior in an economic way by offering more money for housing located in highly improved environmental areas. The hedonic regression results that the housing price decrease while increasing the level of air contamination such substance as carbon monoxide.

  11. Stabilization of the dimeric birch pollen allergen Bet v 1 impacts its immunological properties.

    Science.gov (United States)

    Kofler, Stefan; Ackaert, Chloé; Samonig, Martin; Asam, Claudia; Briza, Peter; Horejs-Hoeck, Jutta; Cabrele, Chiara; Ferreira, Fatima; Duschl, Albert; Huber, Christian; Brandstetter, Hans

    2014-01-03

    Many allergens share several biophysical characteristics, including the capability to undergo oligomerization. The dimerization mechanism in Bet v 1 and its allergenic properties are so far poorly understood. Here, we report crystal structures of dimeric Bet v 1, revealing a noncanonical incorporation of cysteine at position 5 instead of genetically encoded tyrosine. Cysteine polysulfide bridging stabilized different dimeric assemblies, depending on the polysulfide linker length. These dimers represent quaternary arrangements that are frequently observed in related proteins, reflecting their prevalence in unmodified Bet v 1. These conclusions were corroborated by characteristic immunologic properties of monomeric and dimeric allergen variants. Hereby, residue 5 could be identified as an allergenic hot spot in Bet v 1. The presented results refine fundamental principles in protein chemistry and emphasize the importance of protein modifications in understanding the molecular basis of allergenicity.

  12. Impact of Finger Placement on the Correlation Properties of Rake Combined Signals

    Directory of Open Access Journals (Sweden)

    K. B. Baltzis

    2009-12-01

    Full Text Available 3G mobile devices and base stations employ rake receivers. An important issue in the design of such receivers is finger allocation. This paper explores the relationship between finger placement and the correlation properties of rake combined signals. The dependence of correlation coefficients on system parameters such as the multipath characteristics of the propagation channel, the number of users, the processing gain and the thermal noise power is also discussed. Several conclusions useful in the analysis and design of rake receivers are drawn. A low complexity finger placement algorithm is finally suggested. In the proposed receiver, finger allocation is based on the correlation properties of the desired signal component only. The receiver performs close to complex structures in the literature.

  13. Assessing the impacts of intellectual property rights on trade flows in Latin America

    OpenAIRE

    Juan S. Blyde

    2006-01-01

    The protection of intellectual property has been a subject of great contention between developed and developing countries in recent years. Although the Agreement on TRIPs was signed by the members of the World Trade Organization (WTO) during the Uruguay Round of trade negotiations, its provisions are still viewed with animosity by many developing countries. A complete evaluation of the net effects of the TRIPs agreement in developing countries would require a broad assessment of all the costs...

  14. Impact of Crust Matter on Properties of Neutron Star with Supersoft Symmetry Energy

    Institute of Scientific and Technical Information of China (English)

    HUANG Qi-Zhi; WEN De-Hua

    2011-01-01

    By employing three typical equations of states (EOSs) of the crust matter, the effect of the crust on the structure and properties are investigated, where the core matter is described by the MDIxl model and the non-Newtonian gravity (described by the Yukawa contribution) is considered.It is shown that the EOSs of the crust matter have a notable effect on the mass-radius relation and the moment of inertia.

  15. Impact of Different Surface Ligands on the Optical Properties of PbS Quantum Dot Solids

    OpenAIRE

    Fan Xu; Luis Felipe Gerlein; Xin Ma; Chelsea R. Haughn; Doty, Matthew F.; Cloutier, Sylvain G.

    2015-01-01

    The engineering of quantum dot solids with low defect concentrations and efficient carrier transport through a ligand strategy is crucial to achieve efficient quantum dot (QD) optoelectronic devices. Here, we study the consequences of various surface ligand treatments on the light emission properties of PbS quantum dot films using 1,3-benzenedithiol (1,3-BDT), 1,2-ethanedithiol (EDT), mercaptocarboxylic acids (MPA) and ammonium sulfide ((NH4)2S). We first investigate the influence of differen...

  16. On the impact of indium distribution on the electronic properties in InGaN nanodisks

    KAUST Repository

    Benaissa, M.

    2015-03-09

    We analyze an epitaxially grown heterostructure composed of InGaN nanodisks inserted in GaN nanowires in order to relate indium concentration to the electronic properties. This study was achieved with spatially resolved low-loss electron energy-loss spectroscopy using monochromated electrons to probe optical excitations - plasmons - at nanometer scale. Our findings show that each nanowire has its own indium fluctuation and therefore its own average composition. Due to this indium distribution, a scatter is obtained in plasmon energies, and therefore in the optical dielectric function, of the nanowire ensemble. We suppose that these inhomogeneous electronic properties significantly alter band-to-band transitions and consequently induce emission broadening. In addition, the observation of tailing indium composition into the GaN barrier suggests a graded well-barrier interface leading to further inhomogeneous broadening of the electro-optical properties. An improvement in the indium incorporation during growth is therefore needed to narrow the emission linewidth of the presently studied heterostructures.

  17. Investigating the impact of optical selection effects on observed rest frame prompt GRB properties

    CERN Document Server

    Turpin, Damien; Dezalay, Jean-Pascal; Atteia, Jean-Luc; Klotz, Alain; Dornic, Damien

    2016-01-01

    Measuring gamma-ray burst (GRB) properties in their rest-frame is crucial to understand the physics at work in gamma-ray bursts. This can only be done for GRBs with known redshift. Since redshifts are usually measured from the optical spectrum of the afterglow, correlations between prompt and afterglow emissions may introduce biases in the distribution of rest-frame properties of the prompt emission. Our analysis is based on a sample of 90 GRBs with good optical follow-up and well measured prompt emission. 76 of them have a measure of redshift and 14 have no redshift. We estimate their optical brightness with their R magnitude measured two hours after the trigger and compare the rest frame prompt properties of different classes of GRB afterglow brightness. We find that the optical brightness of GRBs in our sample is mainly driven by their intrinsic afterglow luminosity. We show that GRBs with low and high afterglow optical fluxes have similar Epi , Eiso , Liso , indicating that the rest-frame distributions co...

  18. Investigating the impact of microbial interactions with geologic media on geophysical properties

    Science.gov (United States)

    Davis, Caroline Ann

    The goals of this study were to investigate the effect of: (1) microbial metabolic byproducts, microbial growth, and biofilm formation on the low frequency electrical properties of porous media, (2) biofilm formation on acoustic wave properties, and (3) the natural electrical (self-potential) signatures associated with an in-situ biological permeable reactive barrier (PRB). The results suggest: (1) increases in electrolytic conductivity are consistent with increased concentrations of organic acids and biosurfactants; (2) mineral weathering promoted by organic acids causes increases in electrolytic conductivity, concomitant with increases in major cation concentrations; (3) interfacial conductivity generally parallels microbial cell concentrations and biofilm formation; (4) variations in microbial growth and biofilms causes spatiotemporal heterogeneity in the elastic properties of porous media; (5) SP signatures associated with the injection of groundwater into an in-situ biological PRB are dominated by diffusion potentials induced by the injections. The results suggest that electrolytic conductivity may be useful as an indicator of metabolism, while interfacial conductivity may be used as proxy indicator for microbial growth and biofilm formation in porous media. In addition, acoustic measurements may provide diagnostic spatiotemporal data for the validation of bioclogging models/simulations. Collectively, this study provides further evidence that geophysical measurements are sensitive to microbial-induced changes to geologic media, and may be useful for the detection and monitoring of subsurface microbial growth, activity, and distribution such as in microbial enhanced oil recovery, assessing biofilm barriers used for contaminant remediation, or as sealants for reservoirs in CO2 sequestration studies.

  19. A comparative study of the impact properties of sandwich materials with different cores

    Science.gov (United States)

    Ramakrishnan, K. R.; Shankar, K.; Viot, P.; Guerard, S.

    2012-08-01

    Sandwich panels are made of two high strength skins bonded to either side of a light weight core and are used in applications where high stiffness combined with low structural weight is required. The purpose of this paper is to compare the mechanical response of several sandwich panels whose core materials are different. Sandwich panels with glass fibre-reinforced polymer face sheets were used, combined with five different cores; polystyrene foam, polypropylene honeycomb, two different density Balsa wood and Cork. All specimens were subjected to low velocity impact and their structural response (Force-displacement curves) were compared to quasistatic response of the panel tested using an hemispherical indenter.

  20. A comparative study of the impact properties of sandwich materials with different cores

    Directory of Open Access Journals (Sweden)

    Viot P.

    2012-08-01

    Full Text Available Sandwich panels are made of two high strength skins bonded to either side of a light weight core and are used in applications where high stiffness combined with low structural weight is required. The purpose of this paper is to compare the mechanical response of several sandwich panels whose core materials are different. Sandwich panels with glass fibre-reinforced polymer face sheets were used, combined with five different cores; polystyrene foam, polypropylene honeycomb, two different density Balsa wood and Cork. All specimens were subjected to low velocity impact and their structural response (Force-displacement curves were compared to quasistatic response of the panel tested using an hemispherical indenter.

  1. Impact of cationic diffusion on properties of iron-bearing glass fibres

    DEFF Research Database (Denmark)

    Smedskjaer, Morten M.; Yue, Yuanzheng; Deubener, Joachim;

    2010-01-01

    A silica-rich surface layer of Fe3+-containing aluminosilicate glass fibres is created by means of an inward diffusion process of divalent network modifying cations. The latter is caused by the reduction of Fe3+ to Fe2+ when the fibres undergo a heat treatment at temperatures around the glass...... transition temperature (Tg) in a reducing H2/N2 atmosphere. The thickness of the surface layer can be adjusted by varying the temperature or the duration of the heat treatment. The reduction process has a significant impact on the glass transition and crystallization behaviour, high temperature stability...

  2. Fruška gora mountainous environments - assessing the impact of geological setting and land use on soil properties

    Directory of Open Access Journals (Sweden)

    Đorđević Tamara

    2016-01-01

    Full Text Available On a global scale, it has been found that in the last decades the surface of the vulnerable land and land affected by degradation is increasing and that unsustainable land management is one of the key drivers of land degradation. In order to assess the effect that these changes have on biodiversity and ecosystem services, and to carry out the appropriate planning and management actions for conserving the environment it is essential to identify and quantify changes caused by land degradation. The aim of this study was to determine the impact of geological setting i.e. type of bedrock, and land use on soil physico-chemical properties in vulnerable mountainous areas of Fruškagora. For the purpose of this study the total of 30 soil samples at 0-20 cm depth were collected at four locations on the Fruškagora Mt. Geological setting was serpentinite and marl and land cover was forest and meadow. Following soil properties were determined: pH, redox potential (Eh, electrical conductivity (EC, total dissolved solids (TDS, concentrations of available cations Ca, Mg, K, Na, contents of organic carbon (Corg and nitrogen (N. The correlation between the obtained parameters was tested with two-way ANOVA and Principal Component Analyses (PCA. All of the obtained results indicate that the soil physico-chemical properties depend on geological setting and that rock composition has to be taken into consideration during land management. [Projekat Ministarstva nauke Republike Srbije, br. 176006 i br. 173011

  3. Impact Strength and Flexural Properties Enhancement of Methacrylate Silane Treated Oil Palm Mesocarp Fiber Reinforced Biodegradable Hybrid Composites

    Directory of Open Access Journals (Sweden)

    Chern Chiet Eng

    2014-01-01

    Full Text Available Natural fiber as reinforcement filler in polymer composites is an attractive approach due to being fully biodegradable and cheap. However, incompatibility between hydrophilic natural fiber and hydrophobic polymer matrix restricts the application. The current studies focus on the effects of incorporation of silane treated OPMF into polylactic acid (PLA/polycaprolactone (PCL/nanoclay/OPMF hybrid composites. The composites were prepared by melt blending technique and characterize the composites with Fourier transform infrared spectroscopy (FTIR, thermogravimetric analysis (TGA, and scanning electron microscopy (SEM. FTIR spectra indicated that peak shifting occurs when silane treated OPMF was incorporated into hybrid composites. Based on mechanical properties results, incorporation of silane treated OPMF enhances the mechanical properties of unmodified OPMF hybrid composites with the enhancement of flexural and impact strength being 17.60% and 48.43%, respectively, at 10% fiber loading. TGA thermogram shows that incorporation of silane treated OPMF did not show increment in thermal properties of hybrid composites. SEM micrographs revealed that silane treated OPMF hybrid composites show good fiber/matrix adhesion as fiber is still embedded in the matrix and no cavity is present on the surface. Water absorption test shows that addition of less hydrophilic silane treated OPMF successfully reduces the water uptake of hybrid composites.

  4. Impact strength and flexural properties enhancement of methacrylate silane treated oil palm mesocarp fiber reinforced biodegradable hybrid composites.

    Science.gov (United States)

    Eng, Chern Chiet; Ibrahim, Nor Azowa; Zainuddin, Norhazlin; Ariffin, Hidayah; Yunus, Wan Md Zin Wan

    2014-01-01

    Natural fiber as reinforcement filler in polymer composites is an attractive approach due to being fully biodegradable and cheap. However, incompatibility between hydrophilic natural fiber and hydrophobic polymer matrix restricts the application. The current studies focus on the effects of incorporation of silane treated OPMF into polylactic acid (PLA)/polycaprolactone (PCL)/nanoclay/OPMF hybrid composites. The composites were prepared by melt blending technique and characterize the composites with Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). FTIR spectra indicated that peak shifting occurs when silane treated OPMF was incorporated into hybrid composites. Based on mechanical properties results, incorporation of silane treated OPMF enhances the mechanical properties of unmodified OPMF hybrid composites with the enhancement of flexural and impact strength being 17.60% and 48.43%, respectively, at 10% fiber loading. TGA thermogram shows that incorporation of silane treated OPMF did not show increment in thermal properties of hybrid composites. SEM micrographs revealed that silane treated OPMF hybrid composites show good fiber/matrix adhesion as fiber is still embedded in the matrix and no cavity is present on the surface. Water absorption test shows that addition of less hydrophilic silane treated OPMF successfully reduces the water uptake of hybrid composites.

  5. Impact of anti-tacking agents on properties of gas-entrapped membrane and effervescent floating tablets.

    Science.gov (United States)

    Kriangkrai, Worawut; Puttipipatkhachorn, Satit; Sriamornsak, Pornsak; Pongjanyakul, Thaned; Sungthongjeen, Srisagul

    2014-12-01

    Tackiness caused by the gas-entrapped membrane (Eudragit(®)RL 30D) was usually observed during storage of the effervescent floating tablets, leading to failure in floatation and sustained release. In this work, common anti-tacking agents (glyceryl monostearate (GMS) and talc) were used to solve this tackiness problem. The impact of anti-tacking agent on the properties of free films and corresponding floating tablets was investigated. GMS was more effective than talc in reducing tackiness of the film. Addition and increasing amount of anti-tacking agents lowered the film mechanical strength, but the coating films were still strong and flexible enough to resist the generated gas pressure inside the floating tablet. Wettability and water vapor permeability of the film decreased with increasing level of anti-tacking agents as a result of their hydrophobicity. No interaction between anti-tacking agents and polymer was observed as confirmed by Fourier transform infrared spectroscopy, powder X-ray diffractometry, and differential scanning calorimetry studies. Increasing amount of anti-tacking agents decreased time to float and tended to retard drug release of the floating tablets. Floating properties and drug release were also influenced by type of anti-tacking agents. The obtained floating tablets still possessed good floating properties and controlled drug release even though anti-tacking agent had some effects. The results demonstrated that the tackiness problem of the floating tablets could be solved by incorporating anti-tacking agent into the gas-entrapped membrane.

  6. Protecting intellectual property associated with Canadian academic clinical trials - approaches and impact

    Directory of Open Access Journals (Sweden)

    Ross Sue

    2012-12-01

    Full Text Available Abstract Intellectual property is associated with the creative work needed to design clinical trials. Two approaches have developed to protect the intellectual property associated with multicentre trial protocols prior to site initiation. The ‘open access’ approach involves publishing the protocol, permitting easy access to the complete protocol. The main advantages of the open access approach are that the protocol is freely available to all stakeholders, permitting them to discuss the protocol widely with colleagues, assess the quality and rigour of the protocol, determine the feasibility of conducting the trial at their centre, and after trial completion, to evaluate the reported findings based on a full understanding of the protocol. The main potential disadvantage of this approach is the potential for plagiarism; however if that occurred, it should be easy to identify because of the open access to the original trial protocol, as well as ensure that appropriate sanctions are used to deal with plagiarism. The ‘restricted access’ approach involves the use of non-disclosure agreements, legal documents that must be signed between the trial lead centre and collaborative sites. Potential sites must guarantee they will not disclose any details of the study before they are permitted to access the protocol. The main advantages of the restricted access approach are for the lead institution and nominated principal investigator, who protect their intellectual property associated with the trial. The main disadvantages are that ownership of the protocol and intellectual property is assigned to the lead institution; defining who ‘needs to know’ about the study protocol is difficult; and the use of non-disclosure agreements involves review by lawyers and institutional representatives at each site before access is permitted to the protocol, significantly delaying study implementation and adding substantial indirect costs to research institutes

  7. Impact of tillage on soil magnetic properties: results over thirty years different cultivation plots

    Science.gov (United States)

    Thiesson, Julien; Kessouri, Pauline; Buvat, Solène; Tabbagh, Alain

    2010-05-01

    Cultivation may favour or not different processes such as air and water circulation, organic matter and fertilizers supplies..., consequently it can a priori induce significant changes in local oxido-reduction conditions which determine the magnetic properties of soils: the soil magnetic signal. If laboratory measurements on soil samples can be slow and irreversible, it is also possible to perform in field measurements by using electromagnetic devices that allow quick and easy measuring over the relevant soil thicknesses both in time (TDEM) and frequency (FDEM) domains. The object of this study is to compare the variation of two magnetic properties (magnetic susceptibility, measured by FDEM apparatus and magnetic viscosity measured by TDEM apparatus) and there ratio along depth for three different types of tillage (no tillage, ploughing, and simplified tillage). An experimental plot of 80 m by 50 m total area, on which these three types of tillage have been conducted for more than thirty years, was surveyed. The plot is divided in five strips of 16 m by 50 m area, each of which being cultivated by one type of tillage only. Each strip is divided in two parts, one half with nitrogen-fixing crop during intercultivation winter period and the other half with bare soil during this period. On each part, the variation along depth of both magnetic properties was assessed by surveying with different devices corresponding to three different volumes of investigation. For the magnetic susceptibility measurements the devices used were the MS2 of Bartington Ltd with the MS2D probe and the CS60 a slingram prototype use in VCP and HCP configurations. For the magnetic viscosity, the devices used were the DECCO from Littlemore ltd. And the VC100, a slingram prototype, used at two heights. Eleven values of the two magnetic properties have been recorded using each device and their medians calculated. The data were inverted to define the median magnetic profiles of each half

  8. Protecting intellectual property associated with Canadian academic clinical trials--approaches and impact.

    Science.gov (United States)

    Ross, Sue; Magee, Laura; Walker, Mark; Wood, Stephen

    2012-12-27

    Intellectual property is associated with the creative work needed to design clinical trials. Two approaches have developed to protect the intellectual property associated with multicentre trial protocols prior to site initiation. The 'open access' approach involves publishing the protocol, permitting easy access to the complete protocol. The main advantages of the open access approach are that the protocol is freely available to all stakeholders, permitting them to discuss the protocol widely with colleagues, assess the quality and rigour of the protocol, determine the feasibility of conducting the trial at their centre, and after trial completion, to evaluate the reported findings based on a full understanding of the protocol. The main potential disadvantage of this approach is the potential for plagiarism; however if that occurred, it should be easy to identify because of the open access to the original trial protocol, as well as ensure that appropriate sanctions are used to deal with plagiarism. The 'restricted access' approach involves the use of non-disclosure agreements, legal documents that must be signed between the trial lead centre and collaborative sites. Potential sites must guarantee they will not disclose any details of the study before they are permitted to access the protocol. The main advantages of the restricted access approach are for the lead institution and nominated principal investigator, who protect their intellectual property associated with the trial. The main disadvantages are that ownership of the protocol and intellectual property is assigned to the lead institution; defining who 'needs to know' about the study protocol is difficult; and the use of non-disclosure agreements involves review by lawyers and institutional representatives at each site before access is permitted to the protocol, significantly delaying study implementation and adding substantial indirect costs to research institutes. This extra step may discourage sites from

  9. 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.

  10. On the impact of the magnitude of Interstellar pressure on physical properties of Molecular Cloud

    Science.gov (United States)

    Anathpindika, S.; Burkert, A.; Kuiper, R.

    2017-01-01

    Recently reported variations in the typical physical properties of Galactic and extra-Galactic molecular clouds (MCs), and in their star-forming ability have been attributed to local variations in the magnitude of interstellar pressure. Inferences from these surveys have called into question two long-standing beliefs : (1) that MCs are Virialised, and (2) they obey the Larson's third law. Here we invoked the framework of cloud-formation via collision between warm gas-flows to examine if these latest observational inferences can be reconciled. To this end we traced the temporal evolution of the gas surface density, the fraction of dense gas, the distribution of gas column density (N-PDF), and the Virial nature of the assembled clouds. We conclude, these physical properties exhibit temporal variation and their respective peak-magnitude also increases in proportion with the magnitude of external pressure, Pext. The velocity dispersion in assembled clouds appears to follow the power-law, σ _{gas}∝ P_{ext}^{0.23}. The power-law tail at higher densities becomes shallower with increasing magnitude of external pressure for Pext/kB ≲ 107 K cm-3; at higher magnitudes such as those typically found in the Galactic CMZ (Pext/kB > 107 K cm-3), the power-law shows significant steepening. While our results are broadly consistent with inferences from various recent observational surveys, it appears, MCs do not exhibit a unique set of properties, but rather a wide variety that can be reconciled with a range of magnitudes of pressure between 104 K cm-3 - 108 K cm-3.

  11. Impact of Residential Prairie Gardens on the Physical Properties of Urban Soil in Madison, Wisconsin.

    Science.gov (United States)

    Johnston, Marie R; Balster, Nick J; Zhu, Jun

    2016-01-01

    Prairie gardens have become a common addition to residential communities in the midwestern United States because prairie vegetation is native to the region, requires fewer resources to maintain than turfgrass, and has been promoted to help remediate urban soil. Although prairie systems typically have deeper and more diverse root systems than traditional turfgrass, no one has tested the effect of this vegetation type on the physical properties of urban soil. We hypothesized that residential prairie gardens would yield lower soil bulk density (BD), lower penetration resistance (PR), greater soil organic matter (SOM), and greater saturated hydraulic conductivity () compared with turfgrass lawns. To test this hypothesis, we examined 12 residential properties in Madison, WI, where homeowners had established a prairie garden within their turfgrass lawn. Despite a consistent trend in the difference between vegetation types, no significant main effects were found (i.e., a difference between vegetation types when averaged over depth) for any of the four soil properties measured in this study. Differences were found with depth and depended on a significant interaction with vegetation type. At the surface depth (0-0.15 m), soil beneath prairie gardens had 10% lower mean BD, 15% lower mean PR, 25% greater level of SOM, and 33% greater compared with soil beneath the adjacent lawns. These differences were not detected at deeper sampling intervals of 0.15 to 0.30 m and 0.30 to 0.45 m. Although not statistically significant, the consistent trend and direction among soil variables suggest that residential prairie gardens had changed the surface soil at a rate that marginally outpaced turfgrass and calls for controlled experiments to identify the mechanisms that might enhance these trends.

  12. Impact of dry heating on physicochemical properties of corn starch and lysine mixture.

    Science.gov (United States)

    Ji, Ying; Yu, Jicheng; Xu, Yongbin; Zhang, Yinghui

    2016-10-01

    Corn starch was modified with lysine by dry heat treatment and to investigate how they can affect the pasting and structural properties of the treated starches. Dry heating with lysine reduced the pasting temperature and resulting in viscosity increase. The particle size of heated starch-lysine mixture increased, suggesting that starch granules were cross-linked to lysine. After dry heating, the onset temperature, peak temperature and conclusion temperature of corn starch-lysine mixture were lower than those of other starches. The degree of crystallinity decreased for the starch after dry heat treatment while these heated starch samples still have the same X-ray diffraction types as the original starch.

  13. Impact of preacidification of milk and fermentation time on the properties of yogurt.

    Science.gov (United States)

    Peng, Y; Horne, D S; Lucey, J A

    2009-07-01

    Casein interactions play an important role in the textural properties of yogurt. The objective of this study was to investigate how the concentration of insoluble calcium phosphate (CCP) that is associated with casein particles and the length of fermentation time influence properties of yogurt gels. A central composite experimental design was used. The initial milk pH was varied by preacidification with glucono-delta-lactone (GDL), and fermentation time (time to reach pH 4.6 from the initial pH) was altered by varying the inoculum level. We hypothesized that by varying the initial milk pH value, the amount of CCP would be modified and that by varying the length of the fermentation time we would influence the rate and extent of solubilization of CCP during any subsequent gelation process. We believe that both of these factors could influence casein interactions and thereby alter gel properties. Milks were preacidified to pH values from 6.55 to 5.65 at 40 degrees C using GDL and equilibrated for 4 h before inoculation. Fermentation time was varied from 250 to 500 min by adding various amounts of culture at 40 degrees C. Gelation properties were monitored using dynamic oscillatory rheology, and microstructure was studied using fluorescence microscopy. Whey separation and permeability were analyzed at pH 4.6. The preacidification pH value significantly affected the solubilization of CCP. Storage modulus values at pH 4.6 were positively influenced by the preacidification pH value and negatively affected by fermentation time. The value for the loss tangent maximum during gelation was positively affected by the preacidification pH value. Fermentation time positively affected whey separation and significantly influenced the rate of CCP dissolution during fermentation, as CCP dissolution was a slow process. Longer fermentation times resulted in greater loss of CCP at the pH of gelation. At the end of fermentation (pH approximately 4.6), virtually all CCP was dissolved

  14. IMPACT OF INTELLECTUAL PROPERTY RIGHTS ON THE MUSIC AND FILM PIRACY: A GENERAL STUDY

    Directory of Open Access Journals (Sweden)

    PARUL BAJPAI

    2011-01-01

    Full Text Available Film makers, musicians, writers, cinematographers, singers, choreographer…..without copyrights, none of these occupations could claim remuneration. But because culture must be accessible to the greatest number, UNESCO, WTO, WIPO are engaged in seeking the right balance between the interests of the artist and those of the general public. The new techniques of pirating musical recording or DVD’s however, are threatening this fragile equilibrium. This paper presents an overview of the current scenario of music and film piracy in different parts of the world. Intellectual property right is working as a global protector to protect rights of original creator, authors etc.

  15. Impact of densification on microstructure and transport properties of CaFe5O7

    Science.gov (United States)

    Delacotte, C.; Hébert, S.; Hardy, V.; Bréard, Y.; Maki, R.; Mori, T.; Pelloquin, D.

    2016-04-01

    Monophasic CaFe5O7 ceramic has been synthesized by solid state route. Its microstructural features have been studied by diffraction techniques and electron microscopy images before and after Spark Plasma Sintering (SPS) annealings. This work is completed by measurements of electrical and thermal properties. Especially, attention is focused around the structural and electronic transition at 360 K for which specific heat measurements have revealed a sharp peak. Densification by SPS techniques led to a significant improvement of electrical conductivity above 360 K.

  16. Psychometric properties of the Revised Fibromyalgia Impact Questionnaire (FIQR – a contribution to the Portuguese validation of the scale

    Directory of Open Access Journals (Sweden)

    Carlos Costa

    2016-07-01

    Full Text Available Background: Fibromyalgia (FM remains a relatively misunderstood and clinically challenging condition that impact significantly in the individual´s life, impairing global functioning and diminishing quality of life. Management is complex and frequently unsatisfactory, requiring personal tailoring and adaptation of interventions according to the fluctuations of the disease manifestations and their response to therapy. The use of comprehensive and quantified assessment tools constitutes, therefore, an essential component of the management of patients with FM. The Revised Fibromyalgia Impact Questionnaire (FIQR is currently one of the most used and well validated instruments to assess functional (incapacity and global impact of FM and associated symptoms. Objectives: To translate to Portuguese the FIQR and to study its psychometric properties. Material and Methods: The total sample comprised 103 women with fibromyalgia, defined according to the established criteria for FM. A self-report battery composed by the Revised Fibromyalgia Impact Questionnaire (FIQR, the Portuguese version of Beck Depression Inventory-II (BDI-II and the Profile of Mood States (PoMS was administered. The FIQR was re-administered to twenty-four participants, six weeks after the first evaluation. Internal reliability was assessed through Cronbach’s alpha, corrected item-total score correlations and alpha if item deleted. Spearman and Pearson correlations along with repeated measures tests were computed to assess the temporal stability of the scale. Convergent and divergent validity were assessed via Spearman and Pearson correlations. Results: The FIQR demonstrated a good to very good internal consistency (from α = 0.87 to α = 0.94. All items correlated to a good degree (above 0.30 to the total score and contributed significantly to the overall reliability. Moreover, FIQR presented a good temporal stability (from r = .617 to r = .886, p ≤ .001 and favorable convergent and

  17. IMPACT OF DME-DIESEL FUEL BLEND PROPERTIES ON DIESEL FUEL INJECTION SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Elana M. Chapman; Andre Boehman; Kimberly Wain; Wallis Lloyd; Joseph M. Perez; Donald Stiver; Joseph Conway

    2004-04-01

    The objectives of this research program are to develop information on lubricity and viscosity improvers and their impact on the wear mechanisms in fuel injectors operating on blends of dimethyl ether (DME) and diesel fuel. Since DME is a fuel with no lubricity (i.e., it does not possess the lubricating quality of diesel fuel), conventional fuel delivery and fuel injection systems are not compatible with dimethyl ether. Therefore, to operate a diesel engine on DME one must develop a fuel-tolerant injection system, or find a way to provide the necessary lubricity to the DME. In the shuttle bus project, we have chosen the latter strategy in order to achieve the objective with minimal need to modify the engine. Our strategy is to blend DME with diesel fuel, to obtain the necessary lubricity to protect the fuel injection system and to achieve low emissions. In this project, we have sought to develop methods for extending the permissible DME content in the DME-diesel blends without experiencing rapid injector failure due to wear. Our activities have covered three areas: examination of the impact of lubricity additives on the viscosity of DME, development of a high-pressure lubricity test apparatus for studies of lubricity and viscosity improvers and development of an injector durability stand for evaluation of wear rates in fuel injectors. The first two of these areas have resulted in valuable information about the limitations of lubricity and viscosity additives that are presently available in terms of their impact on the viscosity of DME and on wear rates on injector hardware. The third area, that of development of an injector durability test stand, has not resulted in a functioning experiment. Some information is provided in this report to identify the remaining tasks that need to be performed to make the injector stand operational. The key observations from the work are that when blended at 25 wt.% in either diesel fuel or Biodiesel fuel, DME requires more than 5 wt

  18. Impact of energy filtering and carrier localization on the thermoelectric properties of granular semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Narducci, Dario, E-mail: dario.narducci@unimib.it [Department of Materials Science, University of Milano Bicocca, via Cozzi 53, 20125 Milano (Italy); Consorzio DeltaTi Research (Italy); Selezneva, Ekaterina [Department of Materials Science, University of Milano Bicocca, via Cozzi 53, 20125 Milano (Italy); Cerofolini, Gianfranco [Department of Materials Science, University of Milano Bicocca, via Cozzi 53, 20125 Milano (Italy); Consorzio DeltaTi Research (Italy); Frabboni, Stefano; Ottaviani, Giampiero [Department of Physics, University of Modena and Reggio Emilia, via Campi 213, 41100 Modena (Italy)

    2012-09-15

    Energy filtering has been widely considered as a suitable tool to increase the thermoelectric performances of several classes of materials. In its essence, energy filtering provides a way to increase the Seebeck coefficient by introducing a strongly energy-dependent scattering mechanism. Under certain conditions, however, potential barriers may lead to carrier localization, that may also affect the thermoelectric properties of a material. A model is proposed, actually showing that randomly distributed potential barriers (as those found, e.g., in polycrystalline films) may lead to the simultaneous occurrence of energy filtering and carrier localization. Localization is shown to cause a decrease of the actual carrier density that, along with the quantum tunneling of carriers, may result in an unexpected increase of the power factor with the doping level. The model is corroborated toward experimental data gathered by several authors on degenerate polycrystalline silicon and lead telluride. - Graphical abstract: In heavily doped semiconductors potential barriers may lead to both carrier energy filtering and localization. This may lead to an enhancement of the thermoelectric properties of the material, resulting in an unexpected increase of the power factor with the doping level. Highlights: Black-Right-Pointing-Pointer Potential barriers are shown to lead to carrier localization in thermoelectric materials. Black-Right-Pointing-Pointer Evidence is put forward of the formation of a mobility edge. Black-Right-Pointing-Pointer Energy filtering and localization may explain the enhancement of power factor in degenerate semiconductors.

  19. Identify OH groups in TiOF2 and their impact on the lithium intercalation properties

    Science.gov (United States)

    Li, Wei; Body, Monique; Legein, Christophe; Dambournet, Damien

    2017-02-01

    A detailed investigation on the chemical composition of the cubic form of titanium oxyfluoride-based compound reveals the presence of OH groups substituting the oxide/ fluoride sublattice. The substitution of oxide by hydroxyl groups induces the presence of titanium vacancies (□) which were characterized by 1H and 19F solid-state NMR. 1H NMR shows that OH groups are present as bridging Ti-OH-Ti or terminal OH groups, i.e. sitting close to a titanium vacancy Ti-OH-□. The electrochemical properties vs. Li+/Li indicates that the presence of OH groups prevents the intercalation of lithium in the upper voltage region (1.2-3 V vs. Li+/Li). Indeed, a partial dehydroxylation of the framework enables to improve the reversibility of the lithium insertion/de-insertion processes. Since the presence of OH groups in this type of compounds is usual and depends on the synthesis method employed, this work enables to rationalize the different electrochemical behaviors reported in the literature and further highlights the importance of a good knowledge of the chemical composition with regard to the physico-chemical properties.

  20. Pulsed Vacuum Osmotic Dehydration of Cherry Tomatoes: Impact on Physicochemical Properties and Probiotics Entrapment

    Directory of Open Access Journals (Sweden)

    Pheeraya CHOTTANOM

    2016-03-01

    Full Text Available Osmotic dehydration (OD and pulsed vacuum osmotic dehydration (PVOD were employed to assess the various properties of partially-dehydrated tomatoes. Ascorbic acid and lycopene degradation and color and texture change were determined. The mastership incorporation of probiotics (Lactobacillus acidophilus TISTR 1338 into tomatoes was also investigated. OD mediums (20, 40 and 60 Brix consisted of a mixture of formulated tomato extract (FTE and probiotic cell suspension. PVOD promoting mass transfer was clearly observed in a short-time process compared with OD. The physical and chemical properties of the tomatoes changed significantly after the dehydration processes, especially those of ascorbic acid content compared with lycopene. A more than 50 % loss of ascorbic acid was noted, starting at 10 g /100 g tomatoes of water loss. The hardness values significantly increased, while chroma values decreased. The cell entrapment on the tomatoes was in the range of 8 - 9 log CFU/g tomatoes. The highest entrapment of the probiotic bacteria was found in the long-time process (12 h conducted with 20 Brix FTE for the PVOD and OD processes, while entrapment was decreased by the short-time process (6 h. Using high solution concentration resulted in lower cell entrapment. However, cell entrapment could be increased by using the vacuum process. These results will provide a platform that encourages the inclusion of probiotics in high quality fresh-cut products and semi-moist products. These products can then be considered as alternative probiotic food choice for consumers.

  1. Impact of Nanoparticles on the Microstructure and Properties of Immiscible Polymer Blends: Preliminary Investigations

    Science.gov (United States)

    Filippone, G.; Acierno, D.

    2010-06-01

    The control of the morphology represents one of the most important aspects in designing polymer blends. A particular arrangement of the phases known as co-continuity can be promoted within a narrow range of compositions and using appropriate expedients during the mixing process. The distinguishing feature of co-continuous morphologies is the mutual interpenetration of the phases, which is often desirable as it may result in a remarkable combination of functional and structural properties of the blend constituents. Besides acting on the composition and processing conditions, adding nanoparticles in polymer systems with an existing phase-separated morphology such as polymer blends represents an innovative way to promote co-continuity in blends with low amounts of either phase. In the present work we focus on this topic, investigating the ability of nanoparticles to affect the morphology and properties of different kinds of immiscible polymer blends. In addition, the implications of the microstructural changes promoted by the filler on the high-temperature mechanical behavior of the blends are discussed.

  2. Impact of parasitic thermal effects on thermoelectric property measurements by Harman method

    Science.gov (United States)

    Kwon, Beomjin; Baek, Seung-Hyub; Keun Kim, Seong; Kim, Jin-Sang

    2014-04-01

    Harman method is a rapid and simple technique to measure thermoelectric properties. However, its validity has been often questioned due to the over-simplified assumptions that this method relies on. Here, we quantitatively investigate the influence of the previously ignored parasitic thermal effects on the Harman method and develop a method to determine an intrinsic ZT. We expand the original Harman relation with three extra terms: heat losses via both the lead wires and radiation, and Joule heating within the sample. Based on the expanded Harman relation, we use differential measurement of the sample geometry to measure the intrinsic ZT. To separately evaluate the parasitic terms, the measured ZTs with systematically varied sample geometries and the lead wire types are fitted to the expanded relation. A huge discrepancy (˜28%) of the measured ZTs depending on the measurement configuration is observed. We are able to separately evaluate those parasitic terms. This work will help to evaluate the intrinsic thermoelectric property with Harman method by eliminating ambiguities coming from extrinsic effects.

  3. Impact of cultivation of Mastocarpus stellatus in IMTA on the seaweeds chemistry and hybrid carrageenan properties.

    Science.gov (United States)

    Azevedo, Gabriela; Domingues, Bernardo; Abreu, Helena; Sousa-Pinto, Isabel; Feio, Gabriel; Hilliou, Loic

    2015-02-13

    The biomass yield potential of Mastocarpus stellatus, a commercially attractive carrageenophyte for foods and pharmaceutics, was investigated by cultivating the seaweeds in the nutrient-rich outflow of a commercial fish farm. Results from two consecutive 4 weeks experiments indicate that the cultivation of this seaweed produces a mean biomass of 21 to 40.6 gDW m(-2) day(-1) depending on the time of the experiment. DRIFT and CP-MAS NMR analyses of seaweeds indicate that cultivation during May affected quantitatively the seaweeds chemistry, and thus the chemical and gelling properties of native extracts of kappa/iota-hybrid carrageenan (KI). Overall, algal growth leads to the production of more sulphated KI, the percentage increase varying between 27% and 44% for the two experiments. However, alkali treatment of seaweeds before extraction reduces the variations in gelling properties of KI induced by the algal growth. This study demonstrates the capacity of growing M. stellatus in an integrated multi-trophic aquaculture system for the sustainable production of high value polysaccharides.

  4. Particle stability in dilute fermented dairy drinks: formation of fluid gel and impact on rheological properties.

    Science.gov (United States)

    Kiani, H; Mousavi, M E; Mousavi, Z E

    2010-12-01

    Fluid gels are known to be very shear-thinning materials with yield stress. In this study, the rheological properties of gellan and gellan-pectin fluid gels in fermented dairy drinks were evaluated using viscometric measurements. Both gellan- and gellan-pectin-containing solutions showed the rheological properties of fluid gels resulting in stabilization of particles; but no evidence of a fluid gel was observed for those with pectin alone and those with no hydrocolloid content. Unlike pectin, gellan gum was capable of creating significant values of yield stress and accordingly stabilized colloidal particles and extrinsic added solid particles in the fermented dairy drink. However, pectin improved the stability in combination with gellan. The origin of fluid gel formation was assumed to be both permanent interactions occurring between gellan and proteins, forming hairy particle gels and transient interactions between the particle gels. The significance of yield stress values for particle stability was demonstrated and two methods, including a noteworthy infinite apparent viscosity method and a conventional Bingham approach, were employed to calculate the values of yield stress. Both the methods showed a good application potential due to their simplicity, reasonable results and also wide availability of the instrument applied.

  5. Impact of symmetry on the ferroelectric properties of CaTiO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Biegalski, Michael D.; Qiao, Liang [Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Gu, Yijia; Chen, Long-Qing [Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16801 (United States); Mehta, Apurva [Stanford Synchrotron Lightsource SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); He, Qian; Borisevich, Albina [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Takamura, Yayoi, E-mail: ytakamura@ucdavis.edu [Department of Chemical Engineering and Materials Science, University of California Davis, Davis, California 95616 (United States)

    2015-04-20

    Epitaxial strain is a powerful tool to induce functional properties such as ferroelectricity in thin films of materials that do not possess ferroelectricity in bulk form. In this work, a ferroelectric state was stabilized in thin films of the incipient ferroelectric, CaTiO{sub 3}, through the careful control of the biaxial strain state and TiO{sub 6} octahedral rotations. Detailed structural characterization was carried out by synchrotron x-ray diffraction and scanning transmission electron microscopy. CaTiO{sub 3} films grown on La{sub 0.18}Sr{sub 0.82}Al{sub 0.59}Ta{sub 0.41}O{sub 3} (LSAT) and NdGaO{sub 3} (NGO) substrates experienced a 1.1% biaxial strain state but differed in their octahedral tilt structures. A suppression of the out-of-plane rotations of the TiO{sub 6} octahedral in films grown on LSAT substrates resulted in a robust ferroelectric I4 mm phase with remnant polarization ∼5 μC/cm{sup 2} at 10 K and T{sub c} near 140 K. In contrast, films grown on NGO substrates with significant octahedral tilting showed reduced polarization and T{sub c}. These results highlight the key role played by symmetry in controlling the ferroelectric properties of perovskite oxide thin films.

  6. Impact of a Reducing Agent on the Dynamic Surface Properties of Lysozyme Solutions.

    Science.gov (United States)

    Tihonov, Michael M; Kim, Viktoria V; Noskov, Boris A

    2016-05-01

    Disulfide bond shuffling in the presence of the reducing agents dithiothreitol (DTT) or β-mercaptoethanol (BME) strongly affects the surface properties of lysozyme solutions. The addition of 0.32 mM DTT substantially alters the kinetic dependencies of the dynamic surface elasticity and surface tension relative to those of pure protein solutions. The significant increase in the dynamic surface elasticity likely relates to the cross-linking between lysozyme molecules and the formation of a dense layer of protein globules stabilized by intermolecular disulfide bonds at the liquid/gas interface. This effect differs from the previously described influence of chaotropic denaturants, such as guanidine hydrochloride (GuHCl) and urea, on the surface properties of lysozyme solutions. If both chaotropic and reducing agents are added to protein solutions simultaneously, their effects become superimposed. In the case of mixed lysozyme/GuHCl/DTT solutions, the dynamic surface elasticity near equilibrium decreases as the GuHCl concentration increases because of the gradual loosening of the cross-linked layer of protein globules but remains much higher than that of lysozyme/GuHCl solutions.

  7. Impact of thickness on microscopic and macroscopic properties of Fe-Te-Se superconductor thin films

    Directory of Open Access Journals (Sweden)

    N. Zhang

    2015-04-01

    Full Text Available A series of iron based Fe-Te-Se superconductor thin films depositing on 0.7wt% Nb-doped SrTiO3 at substrate temperatures in the 250°C -450°C range by pulsed laser ablation of a constituents well defined precursor FeTe0.55Se0.55 target sample. We study the possible growth mechanism and its influence on the superconductor properties. Experimental results indicate the superconductive and non-superconductive properties are modulated only by the thickness of the thin films through the temperature range. The films appear as superconductor whenever the thickness is above a critical value ∼30nm and comes to be non-superconductor below this value. Relative ratios of Fe to (Te+Se in the films retained Fe/(Te+Se1 for non-superconductor no matter what the film growth temperature was. The effect of film growth temperature takes only the role of modulating the ratio of Te/Se and improving crystallinity of the systems. According to the experimental results we propose a sandglass film growth mechanism in which the interfacial effect evokes to form a Fe rich area at the interface and Se or Te starts off a consecutive filling up process of chalcogenide elements defect sides, the process is significant before the film thickness reaches at ∼30nm.

  8. Impact of silica-coating on the microwave absorption properties of carbonyl iron powder

    Energy Technology Data Exchange (ETDEWEB)

    Li, J. [School of Science, Lanzhou University of Technology, Lanzhou, Gansu 730050 (China); Feng, W.J., E-mail: wjfeng@lut.cn [State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metal, Lanzhou University of Technology, Lanzhou 730050 (China); School of Science, Lanzhou University of Technology, Lanzhou, Gansu 730050 (China); Wang, J.S.; Zhao, X.; Zheng, W.Q. [School of Science, Lanzhou University of Technology, Lanzhou, Gansu 730050 (China); Yang, H. [State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metal, Lanzhou University of Technology, Lanzhou 730050 (China); School of Science, Lanzhou University of Technology, Lanzhou, Gansu 730050 (China)

    2015-11-01

    Microwave absorption properties, especially the band width and depth of reflection loss are highlighted as key measurement in studies of microwave absorber. In order to improve the band width and depth of reflection loss of carbonyl iron powder (CIP), we prepared SiO{sub 2} layers on the surface of CIP by using tetraethyl orthosilicate (TEOS) as a SiO{sub 2} source and 3-aminopropyl triethoxysilane (APTES) as a surface modifier. SiO{sub 2} layer was formed by the hydrolysis of TEOS. The results show that after treatment the CIP is covered by a 5–10 nm coating layer. Contrast to uncoated samples, coated samples show improved absorption properties. The minimum of reflection loss is −38.8 dB at 11 GHz and the band width of reflection loss exceeding −10 dB is from 8 GHz to 14 GHz. - Highlights: • Silica coatings were prepared on the surface of carbonyl iron powder. • Coating layers were identified by several ways. • We discussed the absorbing mechanism of coated samples. • Reflection loss was significantly improved, the width of RL exceeding −10 dB is from 8 GHz to 14 GHz.

  9. Distinct impact of targeted actin cytoskeleton reorganization on mechanical properties of normal and malignant cells.

    Science.gov (United States)

    Efremov, Yu M; Dokrunova, A A; Efremenko, A V; Kirpichnikov, M P; Shaitan, K V; Sokolova, O S

    2015-11-01

    The actin cytoskeleton is substantially modified in cancer cells because of changes in actin-binding protein abundance and functional activity. As a consequence, cancer cells have distinctive motility and mechanical properties, which are important for many processes, including invasion and metastasis. Here, we studied the effects of actin cytoskeleton alterations induced by specific nucleation inhibitors (SMIFH2, CK-666), cytochalasin D, Y-27632 and detachment from the surface by trypsinization on the mechanical properties of normal Vero and prostate cancer cell line DU145. The Young's modulus of Vero cells was 1300±900 Pa, while the prostate cancer cell line DU145 exhibited significantly lower Young's moduli (600±400 Pa). The Young's moduli exhibited a log-normal distribution for both cell lines. Unlike normal cells, cancer cells demonstrated diverse viscoelastic behavior and different responses to actin cytoskeleton reorganization. They were more resistant to specific formin-dependent nucleation inhibition, and reinforced their cortical actin after detachment from the substrate. This article is part of a Special Issue entitled: Mechanobiology.

  10. The impact of atrazine on several biochemical properties of chernozem soil

    Directory of Open Access Journals (Sweden)

    LJ. RADIVOJEVIC

    2008-10-01

    Full Text Available The impact of the pesticide atrazine on biochemical processes in soil was investigated. Atrazine loadings of 8.0, 40.0 and 80.0 mg/kg soil were laboratory tested in an experiment set up on a clay loam soil. Dehydrogenase activity, change in biomass carbon, soil respiration and metabolic coefficient were examined. The samples were collected for analysis 1, 7, 14, 21, 30 and 60 days after atrazine application. The acquired data indicated that the effect of atrazine on the biochemical activity of the soil depended on its application rate and duration of activity, and the effect was either stimulating or inhibiting. However, the detected changes were found to be transient, indicating that there is no real risk of the compound disrupting the balance of biochemical processes in soil.

  11. Properties of cold ions produced by synchrotron radiation and by charged particle impact

    Science.gov (United States)

    Levin, J. C.; Biedermann, C.; Cederquist, H.; O, C.-S.; Short, R. T.; Sellin, I. A.

    1989-04-01

    Argon recoil ions produced by beams of 0.8 MeV/u Cl 5+ have been detected by time-of-flight (TOF) techniques in coincidence with the loss of from one to five projectile electrons. Recoil-ion energies have been determined to be more than an order of magnitude higher than those of highly charged ions produced by unmonochromatized synchrotron radiation. Charge-state distributions, however, show similarities, suggesting that loss of projectile electrons corresponds, in some cases, to inner-shell target ionization producing vacancy cascades. In an essential improvement to the usual multinomial description of ionization in the independent-electron-ejection model, we find the inclusion of Auger vacancy cascades significantly alters the description of the recoil ion spectra corresponding to the projectile-electron loss. These conclusions are consistent with impact parameters inferred from determination of mean recoil energy.

  12. Tunable Quantum Dot Solids: Impact of Interparticle Interactions on Bulk Properties

    Energy Technology Data Exchange (ETDEWEB)

    Sinclair, Michael B. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Fan, Hongyou [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Brener, Igal [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Liu, Sheng [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Luk, Ting S. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Li, Binsong [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    QD-solids comprising self-assembled semiconductor nanocrystals such as CdSe are currently under investigation for use in a wide array of applications including light emitting diodes, solar cells, field effect transistors, photodetectors, and biosensors. The goal of this LDRD project was develop a fundamental understanding of the relationship between nanoparticle interactions and the different regimes of charge and energy transport in semiconductor quantum dot (QD) solids. Interparticle spacing was tuned through the application of hydrostatic pressure in a diamond anvil cell, and the impact on interparticle interactions was probed using x-ray scattering and a variety of static and transient optical spectroscopies. During the course of this LDRD, we discovered a new, previously unknown, route to synthesize semiconductor quantum wires using high pressure sintering of self-assembled quantum dot crystals. We believe that this new, pressure driven synthesis approach holds great potential as a new tool for nanomaterials synthesis and engineering.

  13. Study of the Impact of Stellar Multiplicity on Planet Occurrence and Properties

    Science.gov (United States)

    Thorp, Rachel; Desert, J.; Baranec, C.; Law, N. M.; Johnson, J. A.; Riddle, R. L.

    2014-01-01

    Stellar multiplicity in an exoplanet host star system is likely to affect planetary formation and evolution. To explore this possibility, we used visible-light adaptive optics to search for the presence of possible bounded stellar companions to known exoplanet host stars. Here we present the results and analysis of 48 exoplanet host stars as imaged by the Robo-AO system on the 1.5-m telescope at Palomar Observatory. For each object, we performed a search for the presence of stellar companions using several techniques, and for each method we assessed its detection limits. Finally, we address the questions of sensitivity, density number, and spectral types of stellar companions from a statistical standpoint, and conclude on the impact of stellar multiplicity to exoplanet host stars.

  14. [Study of spectrum drifting of primary colors and its impact on color rendering properties].

    Science.gov (United States)

    Cui, Xiao-yan; Zhang, Xiao-dong

    2012-08-01

    LEDs are currently used widely to display text, graphics and images in large screens. With red, green and blue LEDs as three primary colors, color rendition will be realized through color mixing. However, LEDs' spectrum will produce drifts with the changes in the temperature environment. With the changes in the driving current simulating changes in the temperature, the three primary color LEDs' spectral drifts were tested, and the drift characteristics of the three primary colors were obtained respectively. Based on the typical characteristics of the LEDs and the differences between LEDs with different colors in composition and molecular structure, the paper analyzed the reason for the spectrum drifts and the drift characteristics of different color LEDs, and proposed the equations of spectrum drifts. Putting the experimental data into the spectrum drift equations, the paper analyzed the impacts of primary colors on the mixed color, pointed out a way to reduce the chromatic aberration, and provided the theory for engineering application of color LEDs.

  15. Psychometric Properties of the Modified Danish Version of the Caregiver Impact Questionnaire

    DEFF Research Database (Denmark)

    Heidemann, Christian Hamilton; Godballe, Christian; Kjeldsen, Anette Drøhse;

    2014-01-01

    characteristic analysis. An anchor-based distribution method was applied for determining minimal important change as perceived by the respondent. RESULTS: Factor analysis confirmed the hypothesized 1-factor structure with an acceptable fit. Cronbach's alpha was .90. In the analysis of construct validity, 88.......9% of the hypothesized correlations were correctly predicted. Intraclass correlation coefficient was 0.87 and smallest detectable change corresponded to approximately one-fourth of the scale. Responsiveness was found to be good and a change score of 13.8 represented minimal important change. CONCLUSION: The modified...... Danish version of the Caregiver Impact Questionnaire is a valid and reproducible measurement tool that is also sensitive to measuring change in the current setting. A change score representing minimal important change as perceived by the respondent is proposed. Results of this study support the use...

  16. IMPACT OF VIBRATORY AND ROTATIONAL SHOT PEENING ONTO SELECTED PROPERTIES OF TITANIUM ALLOY SURFACE LAYER

    Directory of Open Access Journals (Sweden)

    Kazimierz Zaleski

    2014-06-01

    Full Text Available This study presents the results of tests on impact of vibratory and rotational shot peening of the Ti6A12Mo2Cr titanium alloy onto the processed object surface roughness and surface layer microhardness. The external surfaces of ring-shaped samples were shot peened. The preceding process consisted of turning with a cubic boron nitride blade knife. Steel beads, having a diameter of 6 mm, were used as a processing medium. The variable parameters of shot peening were vibrator amplitude and shot peening time. The range of recommended technological parameters for vibratory and rotational shot peening was determined. As a result of shot peening, the surface roughness could be reduced by approximately 4 times and the surface layer could be hardened to the depth of approximately 0.4 mm.

  17. The impact of baking time and bread storage temperature on bread crumb properties.

    Science.gov (United States)

    Bosmans, Geertrui M; Lagrain, Bert; Fierens, Ellen; Delcour, Jan A

    2013-12-15

    Two baking times (9 and 24 min) and storage temperatures (4 and 25 °C) were used to explore the impact of heat exposure during bread baking and subsequent storage on amylopectin retrogradation, water mobility, and bread crumb firming. Shorter baking resulted in less retrogradation, a less extended starch network and smaller changes in crumb firmness and elasticity. A lower storage temperature resulted in faster retrogradation, a more rigid starch network with more water inclusion and larger changes in crumb firmness and elasticity. Crumb to crust moisture migration was lower for breads baked shorter and stored at lower temperature, resulting in better plasticized biopolymer networks in crumb. Network stiffening, therefore, contributed less to crumb firmness. A negative relation was found between proton mobilities of water and biopolymers in the crumb gel network and crumb firmness. The slope of this linear function was indicative for the strength of the starch network.

  18. Impact of High Concentration Solutions on Hydraulic Properties of Geosynthetic Clay Liner Materials

    Directory of Open Access Journals (Sweden)

    Lei Liu

    2012-11-01

    Full Text Available This study focuses on the impact of landfill high concentration solutions erosion on geosynthetic clay liner (GCL materials permeability. The permeation tests on the GCL, submerged using different kinds of solutions with different concentrations, were carried out systematically by taking these chemical solutions as permeant liquids. Based on seasonal variations of ion concentrations in Chenjiachong landfill leachate (Wuhan Province, CaCl2, MgCl2, NaCl, and KCl were selected as chemical attack solutions to carry out experimental investigations under three concentrations (50 mM, 100 mM, 200 mM and soak times (5, 10, and 20 days. The variation law of the GCL hydraulic conductivity under different operating conditions was analyzed. The relationship between GCL hydraulic conductivity, chemical solutions categories, concentrations, and soak times were further discussed. The GCL hydraulic conductivity, when soaked and permeated with high concentration chemical solutions, increases several times or exceeds two orders of magnitude, as compared with the permeation test under normal conditions that used water as the permeant liquid. This reveals that GCL is very susceptible to chemical attack. For four chemical solutions, the chemical attack effect on GCL hydraulic conductivity is CaCl2 > MgCl2 > KCl > NaCl. The impact of soak times on GCL hydraulic conductivity is the cooperative contribution of the liner chemical attack reaction and hydration swelling. A longer soak time results in a more advantageous hydration swelling effect. The chemical attack reaction restrains the hydration swelling of the GCL. Moreover, the GCL hydraulic conductivity exponentially decreases with the increased amplitude of thickness.

  19. Morphological adaptations for digging and climate-impacted soil properties define pocket gopher (Thomomys spp. distributions.

    Directory of Open Access Journals (Sweden)

    Ariel E Marcy

    Full Text Available Species ranges are mediated by physiology, environmental factors, and competition with other organisms. The allopatric distribution of five species of northern Californian pocket gophers (Thomomys spp. is hypothesized to result from competitive exclusion. The five species in this environmentally heterogeneous region separate into two subgenera, Thomomys or Megascapheus, which have divergent digging styles. While all pocket gophers dig with their claws, the tooth-digging adaptations of subgenus Megascapheus allow access to harder soils and climate-protected depths. In a Northern Californian locality, replacement of subgenus Thomomys with subgenus Megascapheus occurred gradually during the Pleistocene-Holocene transition. Concurrent climate change over this transition suggests that environmental factors--in addition to soil--define pocket gopher distributional limits. Here we show 1 that all pocket gophers occupy the subset of less energetically costly soils and 2 that subgenera sort by percent soil clay, bulk density, and shrink-swell capacity (a mineralogical attribute. While clay and bulk density (without major perturbations stay constant over decades to millennia, low precipitation and high temperatures can cause shrink-swell clays to crack and harden within days. The strong yet underappreciated interaction between soil and moisture on the distribution of vertebrates is rarely considered when projecting species responses to climatic change. Furthermore, increased precipitation alters the weathering processes that create shrink-swell minerals. Two projected outcomes of ongoing climate change--higher temperatures and precipitation--will dramatically impact hardness of soil with shrink-swell minerals. Current climate models do not include factors controlling soil hardness, despite its impact on all organisms that depend on a stable soil structure.

  20. Impact of Lubricant Additives on thePhysicochemical Properties and Activity of Three‐Way Catalysts

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    Chao Xie

    2016-04-01

    Full Text Available As alternative lubricant anti‐wear additives are sought to reduce friction and improve overall fuel economy, it is important that these additives are also compatible with current emissions control catalysts. In the present work, an oil‐miscible phosphorous‐containing ionic liquid (IL, trihexyltetradecylphosphonium bis(2‐ethylhexyl phosphate ([P66614][DEHP], is evaluated for its impact on three‐way catalysts (TWC and benchmarked against the industry standard zinc‐dialkyl‐dithio‐phosphate (ZDDP. The TWCs are aged in different scenarios: neat gasoline (no‐additive, or NA, gasoline+ZDDP, and gasoline+IL. The aged samples, along with the as‐received TWC, are characterized through various analytical techniques including catalyst reactivity evaluation in a bench‐flow reactor. The temperatures of 50% conversion (T50 for the ZDDP‐aged TWCs increased by 30, 24, and 25 °C for NO, CO, and C3H6, respectively, compared to the no‐additive case. Although the IL‐aged TWC also increased in T50 for CO and C3H6, it was notably less than ZDDP, 7 and 9 °C, respectively. Additionally, the IL‐aged samples had higher water‐gas‐shift reactivity and oxygen storage capacity than the ZDDP‐aged TWC. Characterization of the aged samples indicated the predominant presence of CePO4 in the ZDDP‐aged TWC aged by ZDDP, while its formation was retarded in the case of IL where higher levels of AlPO4 is observed. Thus, results in this work indicate that the phosphonium‐phosphate IL potentially has less adverse impact on TWC than ZDDP.