WorldWideScience

Sample records for charpy impact properties

  1. Charpy impact properties of stainless steel weldment in liquefied natural gas pipelines: Effect of low temperatures

    International Nuclear Information System (INIS)

    Highlights: • Low-temperature impact properties of welded stainless steel pipe were investigated. • Microstructure and impact properties of FCC and BCC structured steels were compared. • Microstructural investigation was performed under varying temperature conditions. • Relatively higher absorbed energy in the welded zone was observed and discussed. - Abstract: In this study, an austenitic stainless steel pipe for the transportation of liquefied natural gas (LNG) was gas tungsten arc welded with a wall thickness of 15.1 mm. Low-temperature Charpy V-notch (CVN) impact tests were performed to investigate the effect of low temperatures on the fracture toughness of the welded zone (WZ), heat-affected zone (HAZ), and base metal (BM) of the LNG pipe. For design and safety reasons, it is necessary to investigate the low-temperature impact properties of weld metals, because weld metals have higher susceptibility to embrittlement than their counterpart base metals. In addition, the effects of cubic crystal structures on the CVN impact response were examined to compare the absorbed energy and fracture surfaces of the materials. Charpy impact tests were performed on mild steels with body-centered cubic (BCC) crystal structures for comparison with the test results of welded austenitic stainless steels with face-centered cubic (FCC) crystal structures. The applicable temperatures were examined, and a scanning electron microscope was used to examine the fracture surface morphology of V-notched specimens tested under various temperature conditions. The results revealed that the absorbed energy of the WZ was slightly higher than that of the BM and HAZ in the FCC-crystal-structured welded pipe specimens. In addition, the ductile-to-brittle transition temperature of the BCC-crystal-structured mild steels was examined

  2. Correlation of microstructure and charpy impact properties in API X70 and X80 line-pipe steels

    International Nuclear Information System (INIS)

    This study aims at correlating microstructure and Charpy impact properties in high-toughness API X70 and X80 line-pipe steels. Three kinds of steels were fabricated by varying alloying elements and hot rolling conditions, and their microstructures and Charpy impact properties were investigated. In addition, their effective grain sizes were characterized by the electron back-scatter diffraction (EBSD) analysis. The Charpy impact test results indicated that the steels rolled in the single phase region had the higher upper shelf energy (USE) than the steel rolled in the two phase region because their microstructures were composed of acicular ferrites. In the X80 steel rolled in the single phase region, the decreased energy transition temperature (ETT) could be explained by the decrease in the overall effective grain size due to the presence of acicular ferrite having smaller effective grain size. Thus, it had excellent mechanical properties in yield and tensile strengths, absorbed energy, and transition temperature, except in ductility

  3. 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.

  4. 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.

  5. Evaluation of Charpy impact properties and fracture toughness for irradiated ferritic steels (4)

    International Nuclear Information System (INIS)

    In order to evaluate the radiation-induced shift of fracture toughness from Charpy impact test results for miniaturized specimens, all of the Charpy impact data on high-strength ferritic steels developed by JNC were examined on the basis of the recent progress on the Charpy impact and fracture toughness test methods. Main results obtained are as follows. 1. The radiation-induced shift of fracture toughness is characterized by the shift of the reference fracture toughness temperature, ΔT100, where T100 is the temperature at which the fracture toughness value is 100MPa√ m. ΔT100 is approximately equal to the radiation-induced shift of Charpy DBTT at 41J (ΔT41). Therefore, ΔT100 can be estimated by determining ΔT41 from miniaturized Charpy specimen data. 2. The value of T41 for miniaturized specimens, T41M, can be determined as the test temperature where the absorbed energy is equal to 41/αx[(Bb)3/2F/(Bb)3/2M]. Here, B is the specimen thickness, b is the ligament size and αx[(Bb)3/2F/(Bb)3/2M] is the normalization factor to get the upper shelf energy of full size specimens, USEF, from the mini-size USEM. The values of α is larger than 0.65, depending on the USE of the material. It is also shown that the fracture volume of (Bb)3/2 is more valid than that of Bb2. 3. The following relationship appears to hold between T41F and T41M. T41F - T41M=M=98 - 15.1xln(Bb)3/2, where M is the specimen size correction factor. M also depends on notch geometry and its dependence becomes large with decreasing specimen size. This indicates that the value of T41F can be estimated from T41M by choosing suitable notch geometry. 4. The radiation-induced shift of T41F, ΔT41F, is approximately equal to ΔT41M. This indicates that the estimate of ΔT100 can be made from ΔT41M. 5. For all of the miniaturized Charpy specimen data on high-strength ferritic steels that were irradiated in JOYO and tested at Tohoku University, the values of USEF, T41F, ΔT41F and ΔT100 were successfully

  6. Relation between Charpy impact properties and magnetism in thermally aged Fe-Cu model alloys

    International Nuclear Information System (INIS)

    This study demonstrates the possibility of applying magnetic methods to pressure vessel surveillance for irradiation embrittlement at nuclear power plants. Charpy impact test and magnetic hesteresis measurement were preformed on thermally aged Fe-1.0wt%Cu model alloys with and without pre-deformation. DBTT increased with increasing aging time. However, magnetic hysteresis parameters showed nonmonotonical changes. The phenomena are discussed in terms of Cu precipitation behavior and dislocation structure. (author)

  7. Charpy Impact Test on Polymeric Molded Parts

    OpenAIRE

    Alexandra Raicu

    2012-01-01

    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 ...

  8. 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.

  9. Evaluation of Charpy impact properties and fracture toughness for irradiated ferritic steels (3)

    International Nuclear Information System (INIS)

    Four kinds of ferritic steels, 61FK, 61FS, ASTM A213T9 (F9S) and NSCR9, were irradiated in SMIR-10 at 823 K to (3.2-9.0)x1026 n/m2 (E > 0.1 MeV) and subjected to instrumented Charpy impact tests. The absorbed energy, dynamic yield and maximum loads, brittle fracture load and the deflection to brittle fracture were measured as a function of test temperature and the ductile-to-brittle transition temperature (DBTT) and the upper shelf energy (USE) were evaluated. For the test, Charpy V-notch specimens, JIS-4, were used which had the dimensions of 10x2x55 mm and the V-notch geometry of notch root radius of 0.25 mm, notch of 2 mm and notch angle of 45 degrees. Main results obtained are as follows. 1) The DBTT was less dependent on neutron dose. The DBTT for the higher dose of (8.8-9.0)-1026 n/m2 increased in the order of 61FK, NSCR9, 61FS and F9S. 2) As the neutron dose increased, the USE decreased for 61FK, while it stayed almost constant for 61GS and increased for F9S. The USE for the higher dose decreased in the order of 61FK, NSCR9, 61FS and F9S, which was the same as the increasing order of DBTT. 3) The DBTT shifts, ΔDBTT, due to irradiation with the higher dose level increased in the order of 61FK, 61FS and NSCR9, except for F9S, where the DBTT in the unirradiated state is not available. 4) The change in USE, ΔUSE, due to irradiation with the higher dose increased in the order of 61FS, 61FK and NSCR9, except for F9S. 5) Comparison of the present results with the previous ones irradiated at 723K in SMIR-10 showed that 823K irradiation caused considerably larger embrittlement than 723K irradiation, especially for F9S and 61FK. (author)

  10. Evaluation of Charpy impact properties and fracture toughness for irradiated ferritic steels. 2

    International Nuclear Information System (INIS)

    The instrumented Charpy impact test was performed for two PMC-FM steels, 61FK and 61FS, irradiated at 723 K to 9.0 x 1026 n/m2 (E > 0.1 MeV) in SMIR-10, and the other two steels, ASTM A213T9 and NSCR9, irradiated at 723 K to 3.6 x 1026 n/m2 in SMIR-10. The test was also conducted for unirradiated 61FK. The absorbed energy, dynamic yield load, dynamic maximum load and brittle fracture load were measured as a function of test temperature and the ductile-to-brittle transition temperature (DBTT) and the upper shelf energy (USE) were evaluated. The DBTT was determined in three different ways; the temperature at which the total absorbed energy was one half of USE (DBTT1), the temperature at which the dynamic yield and maximum loads were equal (DBTT2), and the temperature at which the total absorbed energy was equal to 2 J which corresponds to 10 J for full size specimens (DBTT3). For the test, Charpy V-notch specimens, JIS-4, were used which had the dimensions of 10 x 2 x 55 mm and the V-notch geometry of notch root radius of 0.25 mm, notch depth of 2 mm and notch angle of 45 degrees. Main results obtained are as follows. 1) The DBTT showed that DBTT1>DBTT2>DBTT3 for 61FK, 61FS and NSCR9. 2) For unirradiated 61FK the DBTT1 was 202 K and the USE was 16.9 J, while for irradiated 61FK the DBTT1 was 249 K and the USE was 10.8 J. Therefore, the irradiation caused the DBTT1 to increase by 47 K and the USE to decrease by 6.1 J. 3) For irradiated 61FS the DBTT1 was 207 K and the USE was 17.0 J. Since the DBTT1 and USE of unirradiated 61FS were 160 K and 20 J, respectively, it followed that the irradiation caused the DBTT1 to increase by 47 K and the USE to decrease by 3 J. 4) For irradiated F9S the DBTT1 was 166 K and the USE was 21.4 J. 5) For irradiated NSCR9 the DBTT1 was 208 K and the USE was 16.2 J. Since the DBTT1 and USE of unirradiated NSCR9 were 185 K and 16 J, respectively, it followed that the irradiation caused the DBTT1 to increase by 23 K but no decrease in USE. (J.P.N.)

  11. Effect of mechanical alloying atmosphere on the microstructure and Charpy impact properties of an ODS ferritic steel

    International Nuclear Information System (INIS)

    Two types of oxide dispersion strengthened (ODS) ferritic steels, with the composition of Fe-14Cr-2W-0.3Ti-0.3Y2O3 (in weight percent), have been produced by mechanically alloying elemental powders of Fe, Cr, W, and Ti with Y2O3 particles either in argon atmosphere or in hydrogen atmosphere, degassing at various temperatures, and compacting the mechanically alloyed powders by hot isostatic pressing. It was found in particular that mechanical alloying in hydrogen yields a significant reduction in oxygen content in the materials, a lower dislocation density, and a strong improvement in the fast fracture properties of the ODS ferritic steels, as measured by Charpy impact tests.

  12. Effects of Microstructural Inhomogeneity on Charpy Impact Properties for Reactor Pressure Vessel

    International Nuclear Information System (INIS)

    Reactor pressure vessel (RPV) steels are fabricated by vacuum carbon deoxidation (VCD), and then heat treatment of quenching and tempering is conducted after forging. The through-the-thickness variation of microstructure in RPV can occur due to the cooling rate gradient during quenching and inhomogeneous deformation during forging process. The variation of microstructure in RPV affects the mechanical properties, and inhomogeneity in mechanical properties can occur. The evaluation of mechanical properties of RPV is conducted at thickness of 1/4T. In order to evaluate the safety of RPV more correctly, the research about the through-the-thickness variation of microstructure and mechanical properties in RPV is need. 1. The fine low bainite (LB) is the dominant phase at the inner-surface (0T), but coarse upper bainite (UB) is the dominant phase at the center (1/2T). This is because cooling rate gradient from surface to center occurs during quenching. 2. Inter-lath carbides act as fracture initiation site, and it reduces impact toughness. 3. The upper shelf energy is low and the reference temperatures are high at the 1/4T. Impact properties are poor at 1/4T because of the formation of coarse upper bainite structure and coarse inter-lath carbides

  13. Effects of Microstructural Inhomogeneity on Charpy Impact Properties for Reactor Pressure Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Seokmin; Song, Jaemin; Kim, Min-Chul; Choi, Kwon-Jae; Lee, Bong-Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    Reactor pressure vessel (RPV) steels are fabricated by vacuum carbon deoxidation (VCD), and then heat treatment of quenching and tempering is conducted after forging. The through-the-thickness variation of microstructure in RPV can occur due to the cooling rate gradient during quenching and inhomogeneous deformation during forging process. The variation of microstructure in RPV affects the mechanical properties, and inhomogeneity in mechanical properties can occur. The evaluation of mechanical properties of RPV is conducted at thickness of 1/4T. In order to evaluate the safety of RPV more correctly, the research about the through-the-thickness variation of microstructure and mechanical properties in RPV is need. 1. The fine low bainite (LB) is the dominant phase at the inner-surface (0T), but coarse upper bainite (UB) is the dominant phase at the center (1/2T). This is because cooling rate gradient from surface to center occurs during quenching. 2. Inter-lath carbides act as fracture initiation site, and it reduces impact toughness. 3. The upper shelf energy is low and the reference temperatures are high at the 1/4T. Impact properties are poor at 1/4T because of the formation of coarse upper bainite structure and coarse inter-lath carbides.

  14. Effects of nonstandard heat treatment temperatures on tensile and Charpy impact properties of carbon-steel casting repair welds

    International Nuclear Information System (INIS)

    This report discusses carbon steel castings which are used for a number of different components in nuclear power plants, including valve bodies and bonnets. Components are often repaired by welding processes, and both welded components and the repair welds are subjected to a variety of postweld heat treatments (PWHT) with temperatures as high as 899 degrees C (1650 degrees F), well above the normal 593 to 677 degrees C (1100 to 1250 degrees F) temperature range. The temperatures noted are above the A1 transformation temperature for the materials used for these components. A test program was conducted to investigate the potential effects of such ''nonstandard'' PWHTs on mechanical properties of carbon steel casting welds. Four weldments were fabricated, two each with the shielded-metal-arc (SMA) and flux-cored-arc (FCA) processes,with a high-carbon and low-carbon filler metal in each case. All four welds were sectioned and given simulated PWHTs at temperatures from 621 to 899 degrees C (1150 to 1650 degrees F) in increments of 56 degrees C (100 degrees F) and for times of 5, 10, 20, and 40 h at each temperature. Hardness, tensile, and Charpy V-notch (CVN) impact tests were conducted for the as-welded and heat-treated conditions

  15. Effects of Oxides on Tensile and Charpy Impact Properties and Fracture Toughness in Heat Affected Zones of Oxide-Containing API X80 Linepipe Steels

    Science.gov (United States)

    Sung, Hyo Kyung; Sohn, Seok Su; Shin, Sang Yong; Oh, Kyung Shik; Lee, Sunghak

    2014-06-01

    This study is concerned with effects of complex oxides on acicular ferrite (AF) formation, tensile and Charpy impact properties, and fracture toughness in heat affected zones (HAZs) of oxide-containing API X80 linepipe steels. Three steels were fabricated by adding Mg and O2 to form oxides, and various HAZ microstructures were obtained by conducting HAZ simulation tests under different heat inputs. The no. of oxides increased with increasing amount of Mg and O2, while the volume fraction of AF present in the steel HAZs increased with increasing the no. of oxides. The strengths of the HAZ specimens were generally higher than those of the base metals because of the formation of hard microstructures of bainitic ferrite and granular bainite. When the total Charpy absorbed energy was divided into the fracture initiation and propagation energies, the fracture initiation energy was maintained constant at about 75 J at room temperature, irrespective of volume fraction of AF. The fracture propagation energy rapidly increased from 75 to 150 J and saturated when the volume fraction of AF exceeded 30 pct. At 253 K (-20 °C), the total absorbed energy increased with increasing volume fraction of AF, as the cleavage fracture was changed to the ductile fracture when the volume fraction of AF exceeded 45 pct. Thus, 45 vol pct of AF at least was needed to improve the Charpy impact energy, which could be achieved by forming a no. of oxides. The fracture toughness increased with increasing the no. of oxides because of the increased volume fraction of AF formed around oxides. The fracture toughness did not show a visible correlation with the Charpy absorbed energy at room temperature, because toughness properties obtained from these two toughness testing methods had different significations in view of fracture mechanics.

  16. A report on the instrumented Charpy impact test for metallic materials

    International Nuclear Information System (INIS)

    An instrumented testing method has been developed for Charpy impact test for steels, aluminum alloys and other materials. Using the instrumented Charpy testing machine developed, it is clearly estimated that the method is good enough to give us detailed information about the impact properties of these metallic materials. (author)

  17. Instrumented Charpy Impact Property and Analysis of Fracture Surface of Hot Work Tool Steel; Netukan kogu ko no keisoka sharupi shogeki tokusei to hamen kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Yokoi, D.; Tsujii, N. [Sanyo Special Steel Co. Ltd., Hyogo (Japan); Fukaura, K.; Sunada, H. [Himeji Inst.of Tech., Hyogo (Japan)

    1997-06-15

    The effects of hardness and prior austenite grain size on the impact property of hot work tool steel JIS-SKD6 at room temperature were investigated by the analyses of impact fracture surface and of load-deflection diagrams obtained from instrumented Charpy impact test. In order to vary hardness and the grain size, the specimens of SKD6 produced by ingot and powder metallurgy were quenched from different temperatures, i.e., 1303K and 1403K, and then tempered twice at 873K. It was found that most of impact energy was exhausted in crack initiation for every material and the impact fracture modes were divided into three groups. Although the impact energy tended to decrease with increasing hardness, fine-grained structure suppressed the reduction in impact energy due to the enhancement of the resistance to the crack initiation. 2 refs., 11 figs., 2 tabs.

  18. Effects of Cooling Conditions on Microstructure, Tensile Properties, and Charpy Impact Toughness of Low-Carbon High-Strength Bainitic Steels

    Science.gov (United States)

    Sung, Hyo Kyung; Shin, Sang Yong; Hwang, Byoungchul; Lee, Chang Gil; Lee, Sunghak

    2013-01-01

    In this study, four low-carbon high-strength bainitic steel specimens were fabricated by varying finish cooling temperatures and cooling rates, and their tensile and Charpy impact properties were investigated. All the bainitic steel specimens consisted of acicular ferrite, granular bainite, bainitic ferrite, and martensite-austenite constituents. The specimens fabricated with higher finish cooling temperature had a lower volume fraction of martensite-austenite constituent than the specimens fabricated with lower finish cooling temperature. The fast-cooled specimens had twice the volume fraction of bainitic ferrite and consequently higher yield and tensile strengths than the slow-cooled specimens. The energy transition temperature tended to increase with increasing effective grain size or with increasing volume fraction of granular bainite. The fast-cooled specimen fabricated with high finish cooling temperature and fast cooling rate showed the lowest energy transition temperature among the four specimens because of the lowest content of coarse granular bainite. These findings indicated that Charpy impact properties as well as strength could be improved by suppressing the formation of granular bainite, despite the presence of some hard microstructural constituents such as bainitic ferrite and martensite-austenite.

  19. Comparison of microstructural properties and Charpy impact behaviour between different plates of the Eurofer97 steel and effect of isothermal ageing

    Energy Technology Data Exchange (ETDEWEB)

    Stratil, Ludek [Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Zizkova 22, 616 62 Brno (Czech Republic); Hadraba, Hynek, E-mail: hadraba@ipm.cz [Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Zizkova 22, 616 62 Brno (Czech Republic); Bursik, Jiri; Dlouhy, Ivo [Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Zizkova 22, 616 62 Brno (Czech Republic)

    2011-09-30

    Highlights: > Two plates of Eurofer97 steel were tested in thermally unaffected and aged state. > The two plates of Eurofer97 differ significantly in mean prior austenite grain size. > The different grain size lead to different transition temperature between the plates. > Thermal ageing applied lead to slight microstructural changes of the Eurofer97. > The microstructural changes caused small shift of transition temperature. - Abstract: The microstructure and fracture properties of the Eurofer97 steel plates of thickness 14 mm and 25 mm were investigated in as-received state and in state after long-term thermal ageing (550 deg. C/5000 h). Detailed microstructure studies were carried out by means of optical light, electron and quantitative electron microscopy. Mechanical properties were evaluated by means of Charpy impact testing and hardness testing and fracture surfaces were fractographically analysed in macro and microscales. The microstructure of the Eurofer97 consisted of tempered martensite with M{sub 23}C{sub 6} and MX precipitates. Microstructure of 14 mm plate was more homogenous and fine grained than 25 mm plate. Due to different microstructure the t{sub DBTT} of thicker plate was on +10 deg. C higher than for 14 mm plate for which reached -60 deg. C. Slight microstructural changes on the level of subgrain consisting of their partial recrystallization and slight carbide coarsening were observed after applied ageing. The isothermal ageing caused evident shift in t{sub DBTT} about +5 deg. C, which was most likely caused by recrystallization of subgrains.

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

    International Nuclear Information System (INIS)

    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

  1. 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

  2. Magnetic system for the quality control of specimens for Charpy impact test

    Science.gov (United States)

    Martin, R. V.; Castanho, M. A. P.

    2015-10-01

    It was developed a non-destructive testing system based on magnetic methods for characterization of steel specimens, used in calibration of Charpy impact testing machines. The magnetic properties saturation, remanence, coercivity, and the hysteresis curves were used to create a "magnetic signature" of reference to ensure the value of energy absorbed by these standard specimens.

  3. Enhancement of Charpy impact value by electron beam irradiation of carbon fiber reinforced polymer

    International Nuclear Information System (INIS)

    Influences of electron beam irradiation on Charpy impact value of carbon fiber reinforced polymer (CFRP) have been investigated. The irradiation, which is one of short-time treatments, enhanced the Charpy impact value of CFRP. Furthermore, strengthening of carbon fiber, ductility enhancement of polymer and interface effects on impact test explains the impact value enhancement of CFRP. (author)

  4. 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.

  5. Development of dissimilar welding technique between PNC-FMS wrapper tube and SUS316 steel. 1. Investigation of δ ferrite formation and evaluation of Charpy impact property

    International Nuclear Information System (INIS)

    Ferritic/Martensitic steel (PNC-FMS) with superior resistance to swelling is being developed as wrapper tube for the long-life core of large-scale fast breeder reactor. If the δ ferrite phase would be formed at heat affected zone (HAZ) in welding between PNC-FMS wrapper tube and SUS316 steel, and thus toughness degradation would be suspected due to δ ferrite formation. In this study, the formation of the δ ferrite in applying TIG welding and EB welding are investigated using base metal of 3 types, which are Nieq max./Creq min., Nieq min./Creq max. and the center of chemical composition in the specification. The effect of the amount of the δ ferrite formation and characteristics of toughness change with thermal aging were evaluated. The results are summarized as follows. 1. The δ ferrite generation can be suppressed in the combination of welding process and chemical composition. (1) In case of specification center, the δ ferrite formation can be suppressed about 1% by EB welding. (2) In case of Nieq max./Creq min. in the specification, the δ ferrite formation can be perfectly suppressed even in TIG welding or EB welding. 2. The relationship between δ ferrite content and Charpy impact value was investigated using 3 types of chemical composition in the specification. (1) Ductile Brittle Transition Temperature (DBTT) increased, when δ ferrite content increases. (2) DBTT shift by aging is within about 23degC. (3) DBTT is influenced by grain size and it is lower as the fine grain (grain no.11). (4) Upper Shelf Energy (USE) is not dependent on the δ ferrite content. (author)

  6. 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.

  7. Tensile and Charpy impact properties of an ODS ferritic/martensitic steel 9Cr–1.8W–0.5Ti–0.35Y2O3

    International Nuclear Information System (INIS)

    Highlights: • The tensile property and Charpy impact were tested. • Both strength and plasticity in LT direction are better than that of TL direction. • The LSE was more than 65% of the USE from absorbed energy curve. • The initiation and propagation energy at different temperatures were calculated. • High LSE and dimples on the fracture surface indicated good toughness at −60 °C. - Abstract: A 9Cr-ODS ferritic/martensitic steel with a composition of 9Cr–1.8W–0.5Ti–0.35Y2O3 was fabricated by mechanical alloying and hot isostatic pressing, followed by hot rolling. Tensile properties were measured at room temperature (23 °C) and 700 °C in the rolling direction (LT) and the transverse direction (TL). The ultimate tensile strength (UTS) of the as-rolled samples in both directions reached 990 MPa at 23 °C, and still maintained at 260 MPa at 700 °C. The tensile strength and elongation of the rolling direction was greater than that of the transverse direction. The Charpy impact was tested from −100 to 100 °C in the LT direction. The lower shelf energy (LSE) was more than 65% of the upper shelf energy (USE). The total absorbed energy was separated into the energies for crack initiation and propagation. The propagation energy was always higher than the initiation energy in the range of temperatures tested. The ductile-to-brittle transition temperature (DBTT) of the rolled 9Cr ODS evaluated by an absorbed energy curve was about 0 °C. However, the high LSE and the fracture surface that still contained dimples at lower shelf indicated good toughness of the as-rolled 9Cr ODS steels at temperature of −60 °C

  8. Tensile and Charpy impact properties of an ODS ferritic/martensitic steel 9Cr–1.8W–0.5Ti–0.35Y{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guangming; Zhou, Zhangjian, E-mail: zhouzhj@mater.ustb.edu.cn; Wang, Man; Li, Shaofu; Zou, Lei; Zhang, Liwei

    2014-04-15

    Highlights: • The tensile property and Charpy impact were tested. • Both strength and plasticity in LT direction are better than that of TL direction. • The LSE was more than 65% of the USE from absorbed energy curve. • The initiation and propagation energy at different temperatures were calculated. • High LSE and dimples on the fracture surface indicated good toughness at −60 °C. - Abstract: A 9Cr-ODS ferritic/martensitic steel with a composition of 9Cr–1.8W–0.5Ti–0.35Y{sub 2}O{sub 3} was fabricated by mechanical alloying and hot isostatic pressing, followed by hot rolling. Tensile properties were measured at room temperature (23 °C) and 700 °C in the rolling direction (LT) and the transverse direction (TL). The ultimate tensile strength (UTS) of the as-rolled samples in both directions reached 990 MPa at 23 °C, and still maintained at 260 MPa at 700 °C. The tensile strength and elongation of the rolling direction was greater than that of the transverse direction. The Charpy impact was tested from −100 to 100 °C in the LT direction. The lower shelf energy (LSE) was more than 65% of the upper shelf energy (USE). The total absorbed energy was separated into the energies for crack initiation and propagation. The propagation energy was always higher than the initiation energy in the range of temperatures tested. The ductile-to-brittle transition temperature (DBTT) of the rolled 9Cr ODS evaluated by an absorbed energy curve was about 0 °C. However, the high LSE and the fracture surface that still contained dimples at lower shelf indicated good toughness of the as-rolled 9Cr ODS steels at temperature of −60 °C.

  9. An overview of the principles of modeling Charpy impact energy data using statistical analysis

    International Nuclear Information System (INIS)

    Integrity assessments of Magnox nuclear reactors with steel pressure vessels quantify the temperature margins between the operating temperature of the plant, at any given location, and the onset of upper-shelf temperature. The onset of upper-shelf temperature can be estimated from the fracture toughness properties of each material used in the construction of the pressure vessels. Although start-of-life fracture toughness properties of the materials have been measured, such properties are not available for the neutron-irradiated and thermally aged condition. One of the main effects of neutron irradiation and temperature experienced during service is to increase the ductile-to-brittle transition temperature (DBTT), which can be represented in terms of temperature shifts. In the irradiation surveillance schemes for the Magnox reactors, these temperature shifts can be inferred from Charpy impact energy data which have been measured regularly during the service life. Since Charpy impact energy data are inherently scattered, it is necessary to optimize the interpretation of the data by statistical processing. A recent analysis undertaken by Moskovic et al. concluded that Bayesian analyses are best suited to address the problem. In this overview, the authors consider the requirements of such analyses and the various options available. They then consider the method proposed by Moskovic et al. with respect to the requirements of the inputs to the integrity assessment and the validity of this approach. In this method of analysis, the distribution of all possible values of model coefficients is established by judging the various possible combinations of these model coefficients in relation to the likelihood of the observed data. Analysis of artificially generated data has been used to compare the effectiveness of Bayesian analyses with those used traditionally

  10. Charpy impact test of cloth reinforced epoxide resin at low temperature

    International Nuclear Information System (INIS)

    Charpy impact tests are made on commercial epoxide resin, glass cloth reinforced epoxide and carbon cloth reinforced epoxide at liquid nitrogen temperature and RT. The samples are described, the tests and results presented and illustrated with relevant halftones. The effects of impact velocity and of off-axis angle on the samples are presented. Four conclusions are formulated

  11. Fractographic examination of Charpy impact specimens from the HFIR-MFE-RB2 test

    International Nuclear Information System (INIS)

    The objective of this work is to determine the effect of low temperature irradiation in HFIR on the properties of ferritic stainless steels in order to determine the applicability of these alloys as first wall materials. Selected fracture surfaces of miniature Charpy specimens of HT-9 in base metal, weld metal and heat affected zone (HAZ) metal conditions, and 9Cr-1Mo in base metal and weld metal conditions have been examined by scanning electron microscopy following irradiation in High Flux Isotope Reactor-Magnetic Fusion Energy-RB2 at 550C to 10 dpa. Hardness measurements have also been made. Comparison of results with results on specimens irradiated to low dose demonstrates only minor changes in fracture behavior, but continued increases in hardness due to irradiation. Therefore, the mechanism controlling the degradation of impact properties does not affect the fracture path but does affect strength. A mechanism is proposed to explain the behavior based on microchemical segregation of carbide forming elements. 5 references, 10 figures, 1 table

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

    International Nuclear Information System (INIS)

    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/cm2. Decrease in fracture toughness J-R curve or JIC 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

  13. 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.

  14. 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.; Energy Technology

    1996-06-05

    The degradation of fracture toughness, tensile, and Charpy-impact properties of Type 308 stainless steel (SS) pipe welds due to thermal aging has been characterized at room temperature and 290 C. Thermal aging of SS welds results in moderate decreases in Charpy-impact strength and fracture toughness. For the various welds in this study, upper-shelf energy decreased by 50-80 J/cm{sup 2}. The decrease in fracture toughness J-R curve or JIC is relatively small. Thermal aging had little or no effect on the tensile strength of the welds. Fracture properties of SS welds are controlled by the distribution and morphology of second-phase particles. Failure occurs by the 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 the 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.

  15. Charpy impact energy evolution, with sensitization treatments, in absence and presence of internal hydrogen in austenitic 304 L

    International Nuclear Information System (INIS)

    Charpy impact energy measurement is a sensitive method, specially at low temperature (-180+-50C), to evaluate the sensitization treatments on austenitic 304 L, in presence or absence of cathodic hydrogen

  16. Effects of V-notch dimensions on charpy impact test results for differently sized miniature specimens of ferritic steel

    International Nuclear Information System (INIS)

    In order to develop the small specimen technology in Charpy impact testing, the effects of V-notch dimensions on the test results were investigated for miniaturized specimens of a ferritic steel, Japanese Ferrite/Martensite Dual Phase Steel (JFMS). The miniaturized Charpy specimens had four different square cross-sections of 3.3, 2, 1.5 and 1 mm, and each of them had a variety of V-notch dimensions (notch depth, notch root radius and notch angle). All of the specimens were subjected to Charpy impact tests between 93 and 373 K using a specially instrumented impact machine. The fracture surfaces of all tested specimens were examined by scanning electron microscopy. The main results obtained are as follows: (1) The ductile-to-brittle transition temperature (DBTT) varied noticeably depending upon the notch dimensions, some of the DBTTs exceeding that of the full size specimens. (2) The DBTTs for the miniaturized specimens were uniquely defined by the elastic stress concentration factor, Kt, leading to an important aspect that the DBTT for the full size specimens can be directly obtained from the DBTT of the miniaturized specimens with a V-notch giving a suitable value of Kt. (3) The upper shelf energy (USE) was dependent only on notch depth or ligament size, indicating that the notch geometry was practically unimportant. When all of the measured USEs were normalized by Bb2 or (Bb)3/2 (B is the specimen thickness, b the ligament size), the normalized USEs of the miniaturized specimens agreed with that of the full size specimens within the range of ±15% except for one specimen whose notch root radius was as large as 0.25 mm. (4) The observed characteristics of fracture surface were essentially the same as those of the full size specimens. The measurement of lateral expansion, or ductility, was more useful in estimating the impact property of JFMS than that of fracture appearance (fibrous fracture). (author)

  17. Clean Cast Steel Technology: Effect of Micro-porosity on Tensile and Charpy Properties of Four Cast Steels

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, John, A.; Bates, Charles, E.

    2005-09-19

    The effect of these large shrink cavities on mechanical properties could be easily calculated using well established engineering formulas. Over the years, increases in computational and metallurgical resources have allowed the modeler to improve accuracy and increase the complexity of numerical predictors. An accurate prediction of micro-porosity, not observable using conventional radiographic techniques, and an engineering understanding of the effect on mechanical properties would give a designer confidence in using a more efficient casting design and a lower safety factor. This will give castings an additional design advantage. The goal of this project is to provide current and future modelers/designers with a tensile and Charpy property dataset for validation of micro-porosity predictors. The response of ultimate strength, elongation, and reduction in area to micro-porosity was very similar in all four alloys. Ultimate strength was largely unaffected by tensile fracture surface porosity until values of about 25% were reached and decreased linearly with increasing values. Elongation and reduction in area decreased sharply after less than 5% fracture surface porosity. Niyama values of about 0.7 were produced sound material and acceptable tensile properties. Ultrasonic velocities of 0.233 in/usec and higher produced acceptable tensile properties. Metallographic examination revealed a ratio of 4-6 to 1 in fracture surface porosity to metallographic porosity. Charpy impact properties were largely unaffected by the microporosity concentrations examined in this study and did not correlate to either Niyama values, fracture surface porosity, or metallographic porosity.

  18. Tensile and Charpy impact behavior of an irradiated three-wire series-arc stainless steel cladding

    International Nuclear Information System (INIS)

    The potential for stainless steel cladding to improve the fracture behavior of an operating nuclear reactor pressure vessel, particularly during certain overcooling transients, may depend greatly on the properties of the irradiated cladding. Therefore, three-wire stainless steel cladding irradiated at temperatures and to fluences relevant to power reactor operation was examined. Postirradiation testing results show that, in the test temperature range from -125 to 288 degrees C, the yield strength increased by 8 to 30%, and ductility insignificantly increased, while there was almost no change in the ultimate tensile strength. All cladding exhibited ductile-to-brittle transition behavior during Charpy impact testing, owing to the dominance of delta-ferrite failures at low temperatures. On the upper shelf, the energy was reduced (owing to irradiation exposure) 15 to 20%, while the lateral expansion was reduced 43 and 41% at 2 and 5 - 1019 n/cm2 (E > 1 MeV), respectively. In addition, radiation damage resulted in 13 and 28 degrees C shifts of the Charpy impact transition temperature at the 41-J level for the low and high fluences, respectively

  19. Charpy impact test of cloth reinforced epoxide resin at low temperatures

    International Nuclear Information System (INIS)

    This chapter attempts to establish a method for obtaining dynamic toughness and to provide basic data for design, using the Charpy impact test at cryogenic temperatures and an epoxide and FRP with epoxide matrix as samples. Examines the failure mechanism and the potential problems associated with the use of these materials in practical applications in superconducting magnets. Concludes that impact strength at room temperature (RT) has larger values than those at liquid nitrogen temperature irrespective of impact velocity; impact strength can be improved by reinforcement using glass or carbon cloths; impact strength of reinforced plastics shows a dependence on off-axis angle and the dependence varies with the type of reinforcement, matrix and specimens shape; and impact strength of glass reinforced plastic (GRP) is larger than that of GRP when the specimen shape is identical

  20. 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.

  1. The production of calibration specimens for impact testing of subsize Charpy specimens

    International Nuclear Information System (INIS)

    Calibration specimens have been manufactured for checking the performance of a pendulum impact testing machine that has been configured for testing subsize specimens, both half-size (5.0 x 5.0 x 25.4 mm) and third-size (3.33 x 3.33 x 25.4 mm). Specimens were fabricated from quenched-and-tempered 4340 steel heat treated to produce different microstructures that would result in either high or low absorbed energy levels on testing. A large group of both half- and third-size specimens were tested at -40 degrees C. The results of the tests were analyzed for average value and standard deviation, and these values were used to establish calibration limits for the Charpy impact machine when testing subsize specimens. These average values plus or minus two standard deviations were set as the acceptable limits for the average of five tests for calibration of the impact testing machine

  2. Charpy impact test results of ferritic alloys from the HFIR-MFE-RB2 test

    International Nuclear Information System (INIS)

    Miniature Charpy specimens of HT-9 in base metal, weld metal and heat affected zone (HAZ) metal conditions, and 9Cr-1Mo in base metal and weld metal conditions have been tested following irradiation in HFIR-MFE-RB2 at 550C to ≅10 dpa. All specimen conditions have degraded properties (both DBTT and USE) in comparison with specimens irradiated to lower dose. 9Cr-Mo degraded more than HT-9 and weld metal performed worse than base metal which performed worse than HAZ material. Property degradation was approximately linear as a function of dose, indicating that degradation response had not saturated by 10 dpa. 6 refs., 2 figs., 2 tabs

  3. Constraint effects on fracture toughness of impact-loaded, precracked Charpy specimens

    International Nuclear Information System (INIS)

    Impact-loaded, precracked Charpy specimens often play a crucial role in irradiation surveillance programs for nuclear power plants. However, the small specimen size B=W=10 mm limits the maximum value of cleavage fracture toughness Jc that can be measured under elastic-plastic conditions without loss of crack tip constraint. In this investigation, plane strain impact analyses provide detailed resolution of crack tip fields for impact-loaded specimens. Crack tip stress fields are characterized in terms of J-Q trajectories and the toughness-scaling model which is applicable for a cleavage fracture mechanism. Results of the analyses suggest deformation limits at fracture in the form of b>MJc/σ0, where M approaches 25-30 for a strongly rate-sensitive material at impact velocities of 3-6 m s-1. Based on direct comparison of the static and dynamic J values computed using a domain integral formulation, a new proposal emerges for the transition time, the time after impact at which interial effects diminish sufficiently for simple evaluation of J using the plastic η factor approach. (orig.)

  4. Analysis of Charpy V-notch impact toughness of irradiated A533-B class 1 plate and four submerged-arc welds

    International Nuclear Information System (INIS)

    Studies of the effects of neutron irradiation on Charpy V-notch impact properties of steels have, in general, included a minimum number of tests for each combination of material and irradiation parameters. The present study attempts to apply statistical analyses with multiple testing at selected temperatures to assess the accuracy and reliability of results. Charpy V-notch impact test specimens were irradiated in the Bulk Shielding Reactor at Oak Ridge National Laboratory at 2880C to target neutron fluences of 2 X 1023 neutrons (n)/m2 (>1 MeV). The materials were ASTM A533-B Class 1 plate (HeavySection Steel Technology Plate 02) and four submerged-arc welds representing current nuclear pressure vessel fabrication practice. Both unirradiated and irradiated specimens were tested by two separate groups and multiple tests were conducted at several selected temperatures. Statistical analyses permitted determination of material and test variability and an interlaboratory comparison. Several Charpy curve-fitting methods were used and results are compared with predictions from several ''trend curve'' expressions

  5. Response of unirradiated and neutron-irradiated vanadium alloys to Charpy-impact loading

    International Nuclear Information System (INIS)

    The ductile-brittle transition temperature (DBTT) was determined by Charpy-impact impact tests for dehydrogenated (<30 appm H) and hydrogenated (400--1200 appm H) V-7.2Cr-14.5Ti, V-9.9Cr-9.2Ti, V-13.5Cr-5.2Ti, V-17.7Ti, V-9.2Cr-4.9Ti, V-9.0Cr-3.2Fe-1.2Zr, V-3.1Ti-0.5Si, V-4.1Cr-4.3Ti, V-4.6Ti, and V-2.5Ti-1.0Si alloys. The DBTT was also determined for the V-13.5Cr-5.2Ti, V-9.2Cr-4.9Ti, V-7.2Cr-14.5Ti, and V-17.7Ti alloys after neutron irradiation at 420 and 600 degrees C to 41--44 atom displacements per atom. The DBTTs determined for these vanadium alloys show that a vanadium alloy containing Cr and/or Ti and Si alloying additions to be used as a structural material in a fusion reactor should contain 3--11 wt % total alloying addition for maximum resistance to hydrogen- and/or irradiation-induced embrittlement. 4 refs., 3 figs., 2 tabs

  6. Application of Instrumented Charpy Method in Characterisation of Materials

    Directory of Open Access Journals (Sweden)

    Željko Alar

    2015-07-01

    Full Text Available Testing of absorbed impact energy according to the Charpy method is carried out to determine the behaviour of a material under the impact load. Instrumented Charpy method allows getting the force displacement curve through the entire test, That curve can be related to force-displacement curve which is obtained by the static tensile test. The purpose of this study was to compare the results of forces obtained by the static tensile test with the forces obtained by the instrumented Charpy method. Experimental part of the work contains testing of the mechanical properties of S275J0 steel by the static tensile test and Impact test on instrumented Charpy pendulum.

  7. Charpy impact test results of ferritic alloys from the HFIR[High Flux Isotope Reactor]-MFE-RB2 test

    International Nuclear Information System (INIS)

    Miniature Charpy specimens of HT-9 in base metal, weld metal and heat affected zone (HAZ) metal conditions, and 9Cr-1Mo in base metal and weld metal conditions have been tested following irradiation in HFIR-MFE-RB2 at 550C to ≅10 dpa. All specimen conditions have degraded properties (both DBTT and USE) in comparison with specimens irradiated to lower dose. 9Cr-Mo degraded more than HT-9 and weld metal performed worse than base metal which performed worse than HAZ material. Property degradation was approximately linear as a function of dose, indicating that degradation response had not saturated by 10 dpa

  8. Tensile testing and scanning electron microscope examination of Charpy impact specimens from the HFBR

    International Nuclear Information System (INIS)

    The Materials Technology Group of the Department of Nuclear Energy (DNE) at Brookhaven National Laboratory (BNL) has performed a fractographic examination of neutron irradiated and unirradiated Charpy ''V'' notch specimens which have been deformed to failure in a tensile testing apparatus. The evaluation was carried out using a scanning electron microscope (SEM) to evaluate the fracture mode. Photomicrographs were then evaluated to determine if ductile areas were present on the fracture surfaces of the specimens. The irradiated tensile tests (Charpy ''V'' notch configuration) showed minimum notch tensile strengths of 37.2 Ksi before failure. The unirradiated 6061 T-6 material exhibited a minimum notch tensile strength of 41.9 Ksi. 2 refs., 21 figs., 1 tab

  9. 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.

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

    International Nuclear Information System (INIS)

    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. Effect of Local Crystallographic Texture on the Fissure Formation During Charpy Impact Testing of Low-Carbon Steel

    Science.gov (United States)

    Ghosh, Abhijit; Patra, Sudipta; Chatterjee, Arya; Chakrabarti, Debalay

    2016-03-01

    The severity of the formation of fissures (also known as splitting or delamination) on the fracture surface of Charpy impact-tested samples of a low-carbon steel has been found to increase with the decrease in finish rolling temperature [1093 K to 923 K (820 °C to 650 °C)]. Combined scanning electron microscopy and electron back-scattered diffraction study revealed that crystallographic texture was the prime factor responsible for the fissure formation. Through-thickness texture band composed of cube [Normal Direction (ND)║] and gamma [ND║] orientations developed during the inter-critical rolling treatment. Strain incompatibility between these two texture bands causes fissure cracking on the main fracture plane. A new approach based on the angle between {001} planes of neighboring crystals has been employed in order to estimate the `effective grain size,' which is used to determine the cleavage fracture stress on different planes of a sample. The severity of fissure formation was found to be directly related to the difference in cleavage fracture stress between the `main fracture plane' and `fissure plane.' Clustering of ferrite grains having cube texture promoted the fissure crack propagation along the transverse `fissure plane,' by increasing the `effective grain size' and decreasing the cleavage fracture stress on that plane.

  12. Effect of Local Crystallographic Texture on the Fissure Formation During Charpy Impact Testing of Low-Carbon Steel

    Science.gov (United States)

    Ghosh, Abhijit; Patra, Sudipta; Chatterjee, Arya; Chakrabarti, Debalay

    2016-06-01

    The severity of the formation of fissures (also known as splitting or delamination) on the fracture surface of Charpy impact-tested samples of a low-carbon steel has been found to increase with the decrease in finish rolling temperature [1093 K to 923 K (820 °C to 650 °C)]. Combined scanning electron microscopy and electron back-scattered diffraction study revealed that crystallographic texture was the prime factor responsible for the fissure formation. Through-thickness texture band composed of cube [Normal Direction (ND)║] and gamma [ND║] orientations developed during the inter-critical rolling treatment. Strain incompatibility between these two texture bands causes fissure cracking on the main fracture plane. A new approach based on the angle between {001} planes of neighboring crystals has been employed in order to estimate the `effective grain size,' which is used to determine the cleavage fracture stress on different planes of a sample. The severity of fissure formation was found to be directly related to the difference in cleavage fracture stress between the `main fracture plane' and `fissure plane.' Clustering of ferrite grains having cube texture promoted the fissure crack propagation along the transverse `fissure plane,' by increasing the `effective grain size' and decreasing the cleavage fracture stress on that plane.

  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. Comparison of impact test results on small and ISO-V type Charpy specimens

    International Nuclear Information System (INIS)

    The ductile-to-brittle transition temperatures were calculated from the impact energies measured on ISO-V and KLST specimens for some non-irradiated, irradiated and both irradiated and annealed quenched and tempered pressure vessel steels at the proposed energy levels 68 J/41 J and 3.1 J/1.9 J, or 28 J and 3.15 J. At the energy levels derived from the mean upper shelf energy (USE) ratio (3.1 J/1.9 J) the transition temperatures were on the average 64 deg. C lower as compared with those measured on the ISO-V specimen. At the energy level 3.15 J derived from the ligament area the transition temperature was on the average 36 deg. C lower than that measured on the ISO-V specimen. For both criteria the standard deviation of the correlation was about 15 deg. C. A procedure was also proposed for calculating the USE of ISO-V specimen from the value measured on the KLST specimen. The transition temperature shifts measured for the irradiated materials on the KLST specimen were up to 30 - 40 deg. C lower than those measured on the ISO-V specimens when the shifts were measured at the levels below 75% USE. The degrees of recovery measured on the KLST specimens were of the same order of magnitude or lower than those measured on the ISO-V specimens. (author). 6 refs, 6 figs

  15. Charpy V-notch properties and microstructures of narrow gap ferritic welds of a quenched and tempered steel plate

    Energy Technology Data Exchange (ETDEWEB)

    Powell, G.L.F.; Herfurth, G. [Commonwealth Scientific and Industrial Research Organization, Woodville (Australia)

    1998-11-01

    Multipass welds of quenched and tempered 50-mm-thick steel plate have been deposited by a single wire narrow gap process using both gas metal arc welding (GMAW) and submerged arc welding (SAW). Of the five welds, two reported much lower Charpy V-notch (CVN) values when tested at {minus} 20 C. The CVN toughness did not correlate with either the welding process or whether the power source was pulsed or nonpulsed. The only difference in the ferritic microstructure between the two welds of low Charpy values and the three of high values was the percentage of acicular ferrite. There was no effect of the percentage of as-deposited reheated zones intersected by the Charpy notch or the microhardness of the intercellular-dendritic regions. In all welds, austenite was the microconstituent between the ferrite laths. The percentage of acicular ferrite correlated with the presence of MnO, TiO{sub 2}, {gamma} Al{sub 2}O{sub 3}, or MnO. Al{sub 2}O{sub 3} as the predominant crystalline compound in the oxide inclusions. In turn, the crystalline compound depended on the aluminum-to-titanium ratio in both the weld deposits and the oxide inclusions. In addition to the presence of less acicular ferrite, the two welds that showed lower Charpy values also reported more oxide inclusions greater than 1 {micro}m in diameter. The combination of more oxide inclusions greater than 1 {micro}m and less acicular ferrite is considered to be the explanation for the lower Charpy values.

  16. Estimation of Charpy notch toughness for thermal aging specimens of cast duplex stainless steel using thermalelectric power measurement

    International Nuclear Information System (INIS)

    The material properties of cast duplex stainless steel, which is used for main coolant pipes of PWR (pressurized water reactor) type nuclear power plants, change due to thermal aging. Therefore it is advisable to evaluate these changes of material properties non-destructively for maintenance of the plant component. In order to establish a non-destructive evaluation procedure for the degree of thermal aging of cast duplex stainless steel, thermoelectric power (TEP) measurements were carried out with a newly made TEP meter for thermal aging specimens, with different ferrite contents, aging temperatures and aging periods. Then the relationship between TEP and notch toughness obtained by Charpy impact test was investigated. As the results: (1) TEP increases due to thermal aging. The higher ferrite content, the higher TEP. The higher aging temperature, the more rapidly TEP increases. (2) Because of the decrease of Charpy notch toughness and the increase of TEP due to the fluctuation of Cr concentration caused by the phase separation of the ferrite phase, TEP increases by thermal aging as the Charpy notch toughness decreases. (3) Regardless of the aging temperature, the specimens with the same ferrite content have the same relationship between Charpy notch toughness and TEP. (4) It is possible to estimate Charpy notch toughness with an error of 100 J/cm2 by TEP in the beginning of aging. Therefore, it can be concluded that we can estimate Charpy notch toughness for cast duplex stainless steel by TEP depending on the ferrite content regardless of the aging temperature. (author)

  17. Effects of oxidation on the impact energy of Hastelloy S and Hastelloy C-4 Charpy V-notch specimens heated in air at 6000 to 8000C

    International Nuclear Information System (INIS)

    The 90SrF2 heat source being developed at PNL utilizes a Hastelloy S or Hastelloy C-4 outer capsule having a 0.5-in.-thick wall to contain the Hastelloy C-276 inner capsule. The primary objective of the study was to demonstrate that the air oxidation of the outer capsule that could occur during heat-source service would not degrade the ductility and Charpy impact strength of the capsule below the licensing requirements given in Section 1.1. The 90SrF2 heat source under development is intended for general-purpose use. Compatibility considerations limit the interface temperature between the 90SrF2 and Hastelloy C-276 inner capsule to a maximum of 8000C. The outer capsule surface temperature will be somewhat less than 8000C, and depending on the service, may be substantially lower. The oxidation tests were therefore carried out at 6000 to 8000C for exposures up to 10,000h to cover the range of temperature the outer capsule might expect to encounter in service. The results showed that the oxidation of Hastelloy S and Hastelloy C-4 in air at 6000 to 8000C is very slow, and both alloys form adherent oxide layers that serve to protect the underlying metal. Subsurface attack of Hastelloy S and Hastelloy C-4 due to oxidation was greater than expected, considering the slow oxidation rates of the two alloys at 6000 to 8000C. Estimates of subsurface attack, determined from micrographs of the oxidized specimens, showed erratic results and it was impossible to assign any type of rate equation to the subsurface attack. A conservative estimate of long-term effects can be made using a linear extrapolation of the test results. There were no significant differences between the room-temperature Charpy impact energy of Hastelloy S and Hastelloy C-4 specimens oxidized in air at 6000 to 8000C and control specimens heated in vacuum

  18. Evaluation of impact and fatigue properties on austempered ductile iron

    OpenAIRE

    Arias Fernández, Sergio

    2009-01-01

    Austempered Ductile Iron (ADI) proved to be an excellent material as it possesses attractive properties: high strength, ductility and toughness are combined with good wear resistance and machinability. In this work impact and the fatigue properties have been evaluated for low alloyed Austempered Ductile Iron. To do this, Charpy-type impact test for austempered ductile iron was performed by the standard ASTM A 327M and Fatigue Crack Growth Rates (FCGR) were measured by the stand...

  19. Influence of Martensite Volume Fraction on Impact Properties of Triple Phase (TP) Steels

    Science.gov (United States)

    Zare, Ahmad; Ekrami, A.

    2013-03-01

    Ferrite-bainite-martensite triple phase (TP) microstructures with different volume fractions of martensite were obtained by changing heat treatment time during austempering at 300 °C. Room temperature impact properties of TP steels with different martensite volume fractions ( V M) were determined by means of Charpy impact testing. The effects of test temperature on impact properties were also investigated for two selected microstructures containing 0 (the DP steel) and 8.5 vol.% martensite. Test results showed reduction in toughness with increasing V M in TP steels. Fracture toughness values for the DP and TP steels with 8.5 vol.% martensite were obtained from correlation between fracture toughness and the Charpy impact energy. Fractography of Charpy specimens confirmed decrease in TP steels' toughness with increasing V M by considering and comparing radial marks and crack initiation regions at the fracture surfaces of the studied steels.

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

    International Nuclear Information System (INIS)

    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

  1. 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.

  2. Reconstitution technology of Charpy surveillance specimens with short insert length

    International Nuclear Information System (INIS)

    As for the shortage of the surveillance specimens to monitor the effect of the irradiation embrittlement of reactor pressure vessels (RPV) materials in case of longer-term operation than present surveillance program of nuclear power plants, the reconstitution of them is considered to be the promising measures. Although the length of the specimen insert is required not less than 18 mm in ASTM E1253-99 which is the technical standard to reconstitute Charpy specimens, the minimum length of the specimen insert required should be 10 mm when L-T direction Charpy specimens that have been applied to the early domestic nuclear power plants are reconstituted into T-L direction specimens in order to test the upper shelf absorbed energy of T-L direction specimens. This paper presents the current status of the research consigned by Ministry of Economy, Trade and Industry (METI) in Japan on the applicability of the reconstituted Charpy specimens with short length of the specimen insert. The length of the specimen insert to preserve the absorbed energy of the Charpy specimen is correlated to the absorbed energy of its material. The significant part of upper shelf energy is attributed to the energy for the plastic deformation zone near V-notch in the Charpy specimen. To preserve the absorbed energy, the anticipated plastically deformed zone shall not be affected by the reconstitution procedure. In order to clarify the condition for preserving the absorbed energy in the case of reconstitution, the preliminary data has been obtained using un-irradiated and irradiated Charpy specimens, and the following results have been obtained by the tests carried out in this research. 1) The plastic deformation widths have been estimated by measuring the hardness distribution near the V-notch of the un-irradiated Charpy impact tested specimens, correlated to the absorbed energy. 2) The absorbed energy shifts of reconstituted, un-irradiated Charpy specimens with various length of the specimen

  3. 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

    International Nuclear Information System (INIS)

    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, σ*, and critical stressed area, A*. Since σ*-A* is independent of size and geometry, it provides a fundamental local measure of cleavage toughness

  4. Results of charpy V-notch impact testing of structural steel specimens irradiated at ∼30 degrees C to 1 x 1016 neutrons/cm2 in a commercial reactor cavity

    International Nuclear Information System (INIS)

    A capsule containing Charpy V-notch (CVN) and mini-tensile specimens was irradiated at ∼ 30 degrees C (∼ 85 degrees F) in the cavity of a commercial nuclear power plant to a fluence of 1 x 1016 neutrons/cm2 (> 1MeV). The capsule included six CVN impact specimens of archival High Flux Isotope Reactor A212 grade B ferritic steel and five CVN impact specimens of a well-studied A36 structural steel. This irradiation was part of the ongoing study of neutron-induced damage effects at the low temperature and flux experienced by reactor supports. The plant operators shut down the plant before the planned exposure was reached. The exposure of these specimens produced no significant irradiation-induced embrittlement. Of interest were the data on unirradiated specimens in the L-T orientation machined from a single plate of A36 structural steel, which is the same specification for the structural steel used in some reactor supports. The average CVN energy of five unirradiated specimens obtained from one region of the plate and tested at room temperature was ∼ 99 J, while the energy of 11 unirradiated specimens from other locations of the same plate was 45 J, a difference of ∼ 220%. The CVN impact energies for all 18 specimens ranged from a low of 32 J to a high of 111 J. Moreover, it appears that the University of Kansas CVN impact energy data of the unirradiated specimens at the 100-J level are shifted toward higher temperatures by about 20 K. The results were an example of the extent of scatter possible in CVN impact testing. Generic values for the CVN impact energy of A36 should be used with caution in critical applications

  5. Failure mechanics of fiber composite notched charpy specimens. [stress analysis

    Science.gov (United States)

    Chamis, C. C.

    1976-01-01

    A finite element stress analysis was performed to determine the stress variation in the vicinity of the notch and far field of fiber composites Charpy specimens (ASTM Standard). NASTRAN was used for the finite element analysis assuming linear behavior and equivalent static load. The unidirectional composites investigated ranged from Thornel 75 Epoxy to S-Glass/Epoxy with the fiber direction parallel to the long dimension of the specimen. The results indicate a biaxial stress state exists in (1) the notch vicinity which is dominated by transverse tensile and interlaminar shear and (2) near the load application point which is dominated by transverse compression and interlaminar shear. The results also lead to the postulation of hypotheses for the predominant failure modes, the fracture initiation, and the fracture process. Finally, the results indicate that the notched Charpy test specimen is not suitable for assessing the impact resistance of nonmetallic fiber composites directly.

  6. 系列冲击试验转变温度的意义及其局限性%Significance and limitations of transition temperature based on series Charpy impact tests

    Institute of Scientific and Technical Information of China (English)

    马伟; 姜自强; 姜安婕

    2011-01-01

    文章采用双曲正切函数模型,对夏比冲击试验转变温度曲线的数学特征和各种定义的转变温度的物理意义进行了分析探讨,明确了以转变温度曲线比较材料低温韧性的2个基本原则,提出指标转变温度的相对性概念和相对指标转变温度定义的严重缺陷,在重要场合,应以2种以上类型的转变温度予以验证,ASTME185给出的方法值得借鉴.%Mathematical characteristics of transition temperature curve and physical significance of several definitions of transition temperature based on Charpy impact tests are analyzed by using the hyperbolic tangent function model. Two principles in comparing low temperature toughness of materials in light of transition temperature curve are proposed. The relativity of temperature transition indexes is discussed and the limitations of the definition of the relative temperature transition indexes is pointed out. In some important situations, verification should be carried out based on two or more types of transition temperature and the method given by ASTM E185 is useful.

  7. Charpy V, an application in Mat lab

    International Nuclear Information System (INIS)

    The obtained results with the system Charpy VV1 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)

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

    International Nuclear Information System (INIS)

    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

  9. Mechanical properties of medieval bloomery iron materials - comparative tensile and charpy-tests on bloomery iron samples and S235JRG2

    Czech Academy of Sciences Publication Activity Database

    Thiele, Á.; Hošek, Jiří

    2015-01-01

    Roč. 59, č. 1 (2015), s. 35-38. ISSN 0324-6051 R&D Projects: GA ČR GAP405/12/2289 Institutional support: RVO:67985912 Keywords : bloomery iron * phosphoric iron * mechanical properties * archaeometallurgy Subject RIV: AC - Archeology, Anthropology, Ethnology

  10. Irradiation programme MANITU: Results of pre-examinations and Charpy tests with unirradiated materials

    International Nuclear Information System (INIS)

    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.)

  11. 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)

  12. Enhancements in Magnesium Die Casting Impact Properties

    Energy Technology Data Exchange (ETDEWEB)

    David Schwam; John F. Wallace; Yulong Zhu; Srinath Viswanathan; Shafik Iskander

    2000-06-30

    The need to produce lighter components in transportation equipment is the main driver in the increasing demand for magnesium castings. In many automotive applications, components can be made of magnesium or aluminum. While being lighter, often times the magnesium parts have lower impact and fatigue properties than the aluminum. The main objective of this study was to identify potential improvements in the impact resistance of magnesium alloys. The most common magnesium alloys in automotive applications are AZ91D, AM50 and AM60. Accordingly, these alloys were selected as the main candidates for the study. Experimental quantities of these alloys were melted in an electrical furnace under a protective atmosphere comprising sulfur hexafluoride, carbon dioxide and dry air. The alloys were cast both in a permanent mold and in a UBE 315 Ton squeeze caster. Extensive evaluation of tensile, impact and fatigue properties was conducted at CWRU on permanent mold and squeeze cast test bars of AZ91, AM60 and AM50. Ultimate tensile strength values between 20ksi and 30ksi were obtained. The respective elongations varied between 25 and 115. the Charpy V-notch impact strength varied between 1.6 ft-lb and 5 ft-lb depending on the alloy and processing conditions. Preliminary bending fatigue evaluation indicates a fatigue limit of 11-12 ksi for AM50 and AM60. This is about 0.4 of the UTS, typical for these alloys. The microstructures of the cast specimens were investigated with optical and scanning electron microscopy. Concomitantly, a study of the fracture toughness in AM60 was conducted at ORNL as part of the study. The results are in line with values published in the literature and are representative of current state of the art in casting magnesium alloys. The experimental results confirm the strong relationship between aluminum content of the alloys and the mechanical properties, in particular the impact strength and the elongation. As the aluminum content increases from about 5

  13. Electron beam welding reconstitution technology of Charpy-V specimens

    International Nuclear Information System (INIS)

    This paper reports results connected with the reconstitution of the Cv-type specimens by electron beam welding technology. The experiments were carried out using a 15 kW Leybold Heraus welding unit in a range of power between 1.5 and 3.5 kW, and welding speed from 0.5cm/s to 1.5 cm/s. Material which used in this study is 15Kh2NMFA reactor pressure vessel steel. Weldability of pressure vessel steel by electron beam was investigated in accordance EN ISO 13919-1 1996. Charpy impact tests show good agreement between original and electron beam reconstituted specimens. (author)

  14. Experiment HFIR-MFE-T3 for low-temperature irradiation of miniaturized Charpy V-notch specimens of nickel-doped ferritic steels

    International Nuclear Information System (INIS)

    The HFIR-MFE-T3 experimental capsule is described. This experiment consists of miniature Charpy V-notch specimens of 12 Cr-1 MoVW and 12 Cr-1 MoVW-2 Ni alloys. The different levels of nickel will result in different helium levels generated during irradiation, and thus will allow for an evaluation of the effect of helium on impact properties. Irradiation of the capsule has started with projected fluence at midplane that will produce 10 dpa expected by January 1982

  15. Parameters controlling the performance of AA319-type alloys Part II. Impact properties and fractography

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z.; Samuel, A.M.; Samuel, F.H.; Ravindran, C.; Doty, H.W.; Valtierra, S

    2004-02-25

    The Charpy impact energy of Al-Si-Cu AA319-type alloys was measured in terms of the total absorbed energy. The Charpy specimens were machined from end-chilled castings to incorporate the effect of cooling rate on the impact properties. Unnotched specimens were used to increase the accuracy of the measurements, and to emphasize the effect of microstructure. The influence of the microconstituents on the impact strength was investigated by adding various alloying elements (i.e. Sr, Fe, and P) to the AA319 base alloy, and applying two different heat treatments (T5, and T6). The results show that strontium-modification enhances the impact properties, so that the Sr-modified AA319 alloy exhibits the highest impact properties compared to the base, and other alloys at any given dendrite arm spacing (DAS). The impact energy increases with increase in cooling rate, while iron, and phosphorus additions have a detrimental influence due, respectively, to the formation of {beta}-Al{sub 5}FeSi, and phosphorus oxide particles during solidification. T6 treatment assists in the even distribution, and dissolution of the microconstituents (including the block-like CuAl{sub 2} particles) into the aluminum matrix. With more Cu available for strengthening during aging, the impact toughness is greatly enhanced. In the unmodified AA319 base alloy, crack initiation, and propagation occur mainly through Si-particle fracture, and the mechanism of void coalescence. In the Sr-modified, 1.2% Fe-containing 319 alloys, however, crack initiation takes place through fragmentation of {beta}-Al{sub 5}FeSi, Si, and CuAl{sub 2} or Cu{sub 2}FeAl{sub 7} particles. Crack propagation occurs through cleavage of the {beta}-Fe platelets, and fracture of the Cu-intermetallics, and brittle Si particles. Such samples exhibit very low impact energies.

  16. Transverse and z-Direction CVN Impact Tests of X65 Line Pipe Steels of Two Centerline Segregation Ratings

    Science.gov (United States)

    Su, Lihong; Li, Huijun; Lu, Cheng; Li, Jintao; Fletcher, Leigh; Simpson, Ian; Barbaro, Frank; Zheng, Lei; Bai, Mingzhuo; Shen, Jianlan; Qu, Xianyong

    2016-08-01

    Centerline segregation occurs as a positive concentration of alloying elements in the mid-thickness region of continuously cast slab. Depending upon its severity, it may affect mechanical properties and potentially downstream processing such as weldability, particularly for high-strength line pipe. The segregation fraction in continuously cast slabs and corresponding hot-rolled strips was assessed on API 5L grade X65 line pipe steels with different levels of segregation, rated as Mannesmann 2.0 and 1.4. The results showed that the segregation fraction in hot-rolled strip samples was in accordance with that assessed in the cast slabs, and the segregated regions in hot-rolled strip samples were found to be discontinuous. Transverse and z-direction CVN impact tests were conducted on the two strips and the results showed that centerline segregation does have an influence on the Charpy impact properties of line pipe steel. Specimens located at segregated regions exhibited lower Charpy impact toughness and strips rolled from slabs with higher segregation levels are more likely to exhibit greater variability in Charpy impact toughness. The influence of centerline segregation on z-direction Charpy impact toughness is more severe than on transverse Charpy impact toughness. Lower Charpy impact toughness and brittle fracture surface with cleavage facets along with rod-shaped MnS inclusions were observed for the strip rolled from slab with 2.0 segregation rating if the Charpy specimens were located at segregated regions. The influence on Charpy impact toughness can be associated with the pearlite structure at the centerline and level of MnS inclusions.

  17. Transverse and z-Direction CVN Impact Tests of X65 Line Pipe Steels of Two Centerline Segregation Ratings

    Science.gov (United States)

    Su, Lihong; Li, Huijun; Lu, Cheng; Li, Jintao; Fletcher, Leigh; Simpson, Ian; Barbaro, Frank; Zheng, Lei; Bai, Mingzhuo; Shen, Jianlan; Qu, Xianyong

    2016-06-01

    Centerline segregation occurs as a positive concentration of alloying elements in the mid-thickness region of continuously cast slab. Depending upon its severity, it may affect mechanical properties and potentially downstream processing such as weldability, particularly for high-strength line pipe. The segregation fraction in continuously cast slabs and corresponding hot-rolled strips was assessed on API 5L grade X65 line pipe steels with different levels of segregation, rated as Mannesmann 2.0 and 1.4. The results showed that the segregation fraction in hot-rolled strip samples was in accordance with that assessed in the cast slabs, and the segregated regions in hot-rolled strip samples were found to be discontinuous. Transverse and z-direction CVN impact tests were conducted on the two strips and the results showed that centerline segregation does have an influence on the Charpy impact properties of line pipe steel. Specimens located at segregated regions exhibited lower Charpy impact toughness and strips rolled from slabs with higher segregation levels are more likely to exhibit greater variability in Charpy impact toughness. The influence of centerline segregation on z-direction Charpy impact toughness is more severe than on transverse Charpy impact toughness. Lower Charpy impact toughness and brittle fracture surface with cleavage facets along with rod-shaped MnS inclusions were observed for the strip rolled from slab with 2.0 segregation rating if the Charpy specimens were located at segregated regions. The influence on Charpy impact toughness can be associated with the pearlite structure at the centerline and level of MnS inclusions.

  18. Effect of potential factors in manufacturing process on mechanical properties of F82H

    International Nuclear Information System (INIS)

    Highlights: • Effects of hot forging and cooling method on mechanical properties were studied. • Differences, inhomogeneity, and anisotropy in tensile and Charpy impact properties were observed for plates with a lower hot forging level. • No significant difference was observed in tensile and Charpy impact properties between air cooled and water quenched samples. - Abstract: A DEMO reactor requires over 3500 tons of reduced activation ferritic/martensitic steel. To prepare such a large quantity of the material with appropriate mechanical properties, it is important to study the effect of various factors in the manufacturing process for mass production. In our work, we focused on the effects of hot forging and the cooling method after normalizing, which have not been previously studied. Plates with three different thicknesses were fabricated from slabs with two different hot forging reduction ratios, and the tensile and Charpy impact properties were evaluated for each of these plates. The plates made using a lower hot forging reduction ratio had different tensile properties, and inhomogeneity and anisotropy were observed in the Charpy impact test results. These results indicate that the hot forging operation to which the ingot is initially subjected must be sufficiently high to ensure that the appropriate mechanical properties are achieved. To test the effect of the cooling method, plates cooled in air and those quenched in water after normalizing were prepared, and tensile and Charpy impact tests were performed on these plates. No significant differences were observed indicating that air cooling is sufficient to obtain the appropriate mechanical properties

  19. 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.

  20. 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.

  1. Correlations between Standard and Miniaturised Charpy-V Specimens

    International Nuclear Information System (INIS)

    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

  2. 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.

  3. Evaluation of impact properties of weld joint of reactor pressure vessel steels with the use of miniaturized specimens

    International Nuclear Information System (INIS)

    The effects of specimen size and location of V-notch on the Charpy impact properties were investigated with different sizes of specimens, standard, CVN-1/2, CVN-1/3, and CVN-1.5 mm, for A533B steel, low Mn, high Cu, high phosphorus (P), and high Cu/P steel weld joint. A part of the specimens was irradiated with neutron at 563 K up to 8x1019 n/cm2. The heat affected zone (HAZ) specimen is the best in the impact properties among the specimens of base metal, HAZ, and weld metal in the steels with 0.003 wt.% P, while it is the worst in the steels with ∼ 0.3 wt.% P. This indicates that the surveillance test of HAZ specimen can be represented by base metal in the case of A533B steels with lower P content (∼ 0.003 wt.%). The effects of notch location and chemical contents on ductile to brittle transition temperature (DBTT) are almost independent of specimen size within an error of ±5 K, indicating that the miniaturized Charpy specimens are applicable and effective in the surveillance tests of reactor pressure vessel steel of extended operation period. After irradiation, the highest DBTT was observed for the specimen with V-notch in base metal in the case of A533B steel and high Cu steel with 0.003 wt.% P. (author)

  4. Effect of constituent phase on mechanical properties of 9Cr–1WVTa reduced activation ferritic–martensitic steels

    International Nuclear Information System (INIS)

    Influence of the formation of ferrite and accompanying carbides in martensite matrix on the tensile and Charpy impact properties was investigated for reduced activation ferritic–martensitic (RAFM) 9Cr–1WVTa steel. As the fractions of ferrite and carbide adjacent to the ferrite grain boundary increase, both tensile and Charpy impact properties deteriorated in as-normalized condition. In particular, the tensile strength and elongation decreased simultaneously, which is believed to be led by the localized deformation in ferrite which is softer than martensite, promoting the formation and growth of voids. In addition, the formation of ferrite was also detrimental to the Charpy impact properties regarding to the absorbed energy because the precipitation of carbides around ferrite were vulnerable to the nucleation and propagation of cleavage cracks. The degradation of tensile properties can be recovered by tempering, but the DBTT temperature still increases with presence of ferrite

  5. Comparison of transition temperature criteria applied for KLST and ISO-V type Charpy specimens

    International Nuclear Information System (INIS)

    A great deal of test data have been obtained on reactor pressure vessel steels using the standard Charpy-V test. Although more advanced test methods, based on elastic-plastic fracture mechanics, are both recommendable and already in use in the surveillance programmes of some nuclear power plants (NPPs), Charpy tests are still required, e.g., by regulatory guides. Besides the normal-size (ISO-V) Charpy specimen (10 x10 x 55 mm3), various types of sub-size specimens have been introduced. One standardised sub-size specimen being in use is the so-called KLST specimen, the size of which is 3 x 4 x 27 mm3 with 1 mm central notch (DIN50 115). So far the test data published for the KLST specimen, as well as sub-size specimens in general, is still limited. The results from small specimen testing are typically used for evaluating the fracture behaviour of the ISO-V Charpy specimen and if there are no test results available for the correlation, as there usually is not, a general correlation has to be applied to evaluate the fracture behaviour of the ISO-V specimen. The availability of a sub-size specimen depends therefore significantly on how reliably this relationship has been established. Impact test data measured with different specimens have been correlated using some appropriate criterion (or criteria) and since a total transition curve is normally measured, there are several ones available. The criterion can be a fixed energy or lateral expansion level describing the transition temperature or the level can be derived from the upper-shelf energy (USE). In general, the proposed criterion can be divided into two groups: those derived from the dimensions of the specimens and those derived empirically from experimental data. Test data measured with ISO-V and KLST-type Charpy specimens are discussed and the validity of two proposed, basically different transition temperature criteria and the resulting differences in the temperatures, that are inevitable because of the

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

    International Nuclear Information System (INIS)

    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.

  7. 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.

  8. Tensile and impact behavior of the reduced-activation steels OPTIFER and F82H mod

    International Nuclear Information System (INIS)

    Tensile and charpy impact tests were carried out on some OPTIFER steel grades and F82H mod. The steels show little difference in tensile properties, but pronounced differences in charpy impact properties. Combinations of low ductile-brittle transition temperature (DBTT) and high yield strength are favored for OPTIFER-IV. After aging at 600 deg. C and higher, F82H mod steel embrittles due to precipitation of Laves phase (Cr, Fe)2W, whereas OPTIFER-IV is resistant to aging

  9. Physical and mechanical properties of cast 17-4 PH stainless steel

    International Nuclear Information System (INIS)

    The physical and mechanical properties of an overaged 17-4 PH stainless steel casting have been examined. The tensile and compressive properties of cast 17-4 PH are only influenced to a slight degree by changing test temperature and strain rate. However, both the Charpy impact energy and dynamic fracture toughness exhibit a tough-to-brittle transition with decreasing temperature - this transition being related to a change in fracture mode from ductile, dimple to cleavage-like. Finally, although the overaged 17-4 PH casting had a relatively low room temperature Charpy impact energy when compared to wrought 17-4 PH, its fracture toughness was at least comparable to that of wrought 17-4 PH. This observation suggests that prior correlations between Charpy impact energies and fracture toughness, as derived from wrought materials, must be approached with caution when applied to cast alloys

  10. Effect of phosphorous and boron addition on microstructural evolution and Charpy impact properties of high-phosphorous-containing plain carbon steels

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Seokmin [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Shin, Sang Yong [Microstructure Physics and Alloy Design, Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf D-40237 (Germany); Lee, Junghoon [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Lee, Chang-Hoon [Next Generation Products Research Group, Technical Research Laboratories, POSCO, Pohang 790-785 (Korea, Republic of); Lee, Sunghak, E-mail: shlee@postech.ac.kr [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

    2013-03-01

    Four plain carbon steels were fabricated by controlling the addition of P and B, and then isothermal heat-treatments were conducted at 550 °C and 650 °C for 3 h on these steels to make ferrite–pearlite-based or ferrite–bainite-based microstructures, respectively. B was added for controlling the reduction in toughness due to grain boundary segregation of P because B was readily distributed on grain boundaries. In the 550 °C-treated steels, bainite grains were refined by the B addition, whereas the 650 °C-treated steels did not show the grain refinement due to the B addition. According to the critical time analysis for non-equilibrium grain boundary segregation of P and B, the present isothermal treatment time of 3 h was too short for the grain boundary segregation of P, and thus the fracture occurred mostly in a cleavage mode, instead of an intergranular mode. Since this 3 h-treatment time was too long for the grain boundary segregation of B, the grain boundary segregation of B was reduced, and the precipitation of cementites was promoted. In the 550 °C-treated steels, the area fraction of intergranular fracture increased with increasing volume fraction of grain boundary cementites, as they played an important role in initiating the intergranular fracture, although the area fraction of intergranular fracture was lower than 5%. In the 650 °C-treated steels having coarse grains, however, grain boundary cementites did not work for intergranular fracture because the crack readily propagated in a cleavage mode.

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

    International Nuclear Information System (INIS)

    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)

  12. Microstructure and mechanical properties of a W–2wt.%Y2O3 composite produced by sintering and hot forging

    International Nuclear Information System (INIS)

    A W–2Y2O3 composite has been developed by powder metallurgy methods in collaboration with the Plansee Company (Austria). The microstructure of the composite was analyzed using transmission electron microscopy and electron backscatter diffraction in scanning electron microscopy. The mechanical properties of the composite were analyzed using nano-indentation experiments, tensile and Charpy impact tests. It was mainly found that the composite exhibits ductile tensile behavior at 673–1273 K but weak Charpy impact properties, characterized by low absorbed energy values, at 773–1273 K

  13. Experimental Investigation of Charpy Impact Tests on Metallic SLM parts

    OpenAIRE

    Yasa, Evren; Deckers, Jan; Kruth, Jean-Pierre; Rombouts, Marleen; Luyten, Jan

    2009-01-01

    Selective laser melting (SLM) is a layer-additive manufacturing technology making it possible to create fully functional parts directly from standard metal powders without using any intermediate binders or any additional post-processing steps. During the process, a laser source selectively scans a powder bed according to the CAD data of the part to be produced and powder particles are completely molten by a high intensity laser beam. SLM is capable of producing near full density metallic part...

  14. Effect of ageing and specimen size on the impact properties of manet II steel

    International Nuclear Information System (INIS)

    Manet steel is one of the martensitic I 2%Cr-I%Mo-v steels family. These steels are used extensively in highly thermally stressed components, such as superheater tubing and main steam pipe systems in power stations, due to their adequate strength at high temperatures. In the present work the effect of ageing at 550 degree C for 1000 h on the impact properties of manet II steel was investigated. Two different Charpy V-notch impact specimens were used: full-size and sub size ones. Tests were carried out on two instrumental impact machines appropriate for the two specimen sizes. Both microstructure and fracture surface were examined using optical and scanning electron microscopy (SEM). The results showed that ageing produced little embrittling effect on MANET II steel. Both the ductile-to-brittle transition temperature (DBTT) and the brittleness transition temperature (TD) were increased by bout 15 degree C. The local fracture stress was also slightly reduced due to the ageing treatment. The results were discussed in the light of the chemical composition and the fracture surface morphology. 12 figs., 3 tabs

  15. Static and impact crack properties of a high-strength steel welded joint

    Energy Technology Data Exchange (ETDEWEB)

    Zrilic, M. [Faculty of Technology and Metallurgy, Karnegijeva 4, 11000 Belgrade (Serbia)]. E-mail: misa@tmf.bg.ac.yu; Grabulov, V. [Military Technical Institute, Ratka Resanovica 1, Belgrade (Serbia); Burzic, Z. [Military Technical Institute, Ratka Resanovica 1, Belgrade (Serbia); Arsic, M. [Institute for Material Testing, Bul. Vojvode Misica 43, Belgrade (Serbia); Sedmak, S. [Faculty of Technology and Metallurgy, Karnegijeva 4, 11000 Belgrade (Serbia)

    2007-03-15

    In order to gain the benefits of weldable high-strength steels in pressurized equipment applications, satisfactory toughness and crack properties of the welded joint, both in the weld metal and the heat-affected -zone (HAZ), are required. Experimental investigations of toughness and crack resistance parameters through static and impact tests of a high-strength, low-alloy steel (HSLA) with a nominal yield strength of 700 MPa and its welded joint, were performed on Charpy-sized specimens, V-notched and pre-cracked, of the parent metal, weld metal and HAZ. The selected electrode produced slight undermatching and enabled the welded joints to be manufactured without cold cracks. The impact energy and its parts responsible for crack initiation and propagation were determined by toughness evaluation. Crack sensitivity, defined as the ratio of the impact energy for V-notched and for pre-cracked specimens, enabled a comparison of the homogeneous microstructure of the parent metal and the weld metal, and of the heterogeneous microstructure of the heat-affected-zone (HAZ), which indicated a better crack toughness behaviour of the HAZ. The results obtained showed that the toughness and crack resistance of the weld metal were significantly lower than those of the parent metal and the HAZ. The fracture mechanics parameters, J {sub Ic} integral, and plane strain fracture toughness, K {sub Ic}, as well as J resistance curves expressed the degradation less.

  16. The impact and hot tensile properties of 9Cr1Mo steel in various heat treatment conditions

    International Nuclear Information System (INIS)

    The impact and elevated temperature tensile properties of 9Cr1Mo in several heat treatment conditions have been studied to test the tolerance of the steel to departures from the material specification for AGR or fast reactor applications. The properties were found not to be sensitive to grain size or to the presence of grain boundary delta ferrite (<5%) which can arise in weld heat affected zones. Prior creep resulted in some loss of tensile strength but no loss of ductility was measured even though secondary precipitation had begun to develop under the conditions of the prior creep test. The dominant variable governing both tensile and impact properties was the state of temper and an empirical relationship was found between the tensile properties and hardness: the latter also being predictable by a Holloman-Jaffe form of expression. However, the Charpy impact properties of specimens aged near the service temperature (at 550 deg. C) were severely reduced by a mode of prior austenite grain boundary embrittlement manifested as severe intercrystalline failure. The embrittlement is of a type consistent with decohesion arising simply from equilibrium segregation (ie temper embrittlement). While the latter appears to make a significant contribution, interface decohesion is believed also to depend on concentration changes associated with carbide growth. (author)

  17. 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.

  18. Phase transformation and impact properties in the experimentally simulated weld heat-affected zone of a reduced activation ferritic/martensitic steel

    International Nuclear Information System (INIS)

    In this work, the phase transformation and impact properties in the weld heat-affected zone (HAZ) of a reduced activation ferritic/martensitic (RAFM) steel are investigated. The HAZs were experimentally simulated using a Gleeble simulator. The base steel consisted of tempered martensite through normalizing at 1000 °C and tempering at 750 °C, while the HAZs consisted of martensite, δ-ferrite and a small volume of autotempered martensite. The impact properties using a Charpy V-notch impact test revealed that the HAZs showed poor impact properties due to the formation of martensite and δ-ferrite as compared with the base steel. In addition, the impact properties of the HAZs further deteriorated with an increase in the δ-ferrite fraction caused by increasing the peak temperature. The impact properties of the HAZs could be improved through the formation of tempered martensite after post weld heat treatment (PWHT), but they remained lower than that of the base steel because the δ-ferrite remained in the tempered HAZs

  19. Characterization by notched and precracked Charpy tests of the in-service degradation of RPV steel fracture toughness

    International Nuclear Information System (INIS)

    The current engineering and regulatory practice to estimate fracture toughness safety margins for nuclear reactor pressure vessels (RPVs) relies heavily on the CVN impact test. Techniques to estimate in-service toughness degradation directly using a variety of precracked specimens are under development worldwide. Emphasis is on their miniaturization. In the nuclear context, it is essential to address many issues such as representativity of the surveillance programs with respect to the vessel in terms of materials and environment, transferability of test results to the structure (constraint and size effects), lower bound toughness certification, creadibility relative to trends of exising databases. An enhanced RPV surveillance strategy in under development in Belgium. It combines state-of-the-art micromechanical and damage modelling to the evaluation of CVN load-deflection signals, tensile stress-strain curves and slow-bend tests of reconstituted precracked Charpy specimens. A probabilistic micromechanical model has been established for static and dynamic transgranular cleavage initiation fracture toughness in the ductile-brittle transition temperature range. This model allows to project toughness bounds for any steel embrittlement condition from the corresponding CVN and static tensile properties, using a single scaling factor defined by imposing agreement with toughness tests in a single condition. The outstanding finding incorporated by this toughness transfer model is that the microcleavage fracture stress is affected by temperature in the ductile-brittle transition and that this influence is strongly correlated to the flow stress: this explains the shape of the KIcn KId temperature curves as well as the actual magnitude of the strain rate and irradiation effects. Furthermore, CVN crack arrest loads and fracture appearance are also taken advantage of in order to estimate KIa degradation. Finally, the CVN-tensile load-temperature diagram provides substantial

  20. Characterization by notched and precracked Charpy tests of the in-service degradation of RPV steel fracture toughness

    Energy Technology Data Exchange (ETDEWEB)

    Fabry, A.

    1997-01-01

    The current engineering and regulatory practice to estimate fracture toughness safety margins for nuclear reactor pressure vessels (RPVs) relies heavily on the CVN impact test. Techniques to estimate in-service toughness degradation directly using a variety of precracked specimens are under development worldwide. Emphasis is on their miniaturization. In the nuclear context, it is essential to address many issues such as representativity of the surveillance programs with respect to the vessel in terms of materials and environment, transferability of test results to the structure (constraint and size effects), lower bound toughness certification, creadibility relative to trends of exising databases. An enhanced RPV surveillance strategy in under development in Belgium. It combines state-of-the-art micromechanical and damage modelling to the evaluation of CVN load-deflection signals, tensile stress-strain curves and slow-bend tests of reconstituted precracked Charpy specimens. A probabilistic micromechanical model has been established for static and dynamic transgranular cleavage initiation fracture toughness in the ductile-brittle transition temperature range. This model allows to project toughness bounds for any steel embrittlement condition from the corresponding CVN and static tensile properties, using a single scaling factor defined by imposing agreement with toughness tests in a single condition. The outstanding finding incorporated by this toughness transfer model is that the microcleavage fracture stress is affected by temperature in the ductile-brittle transition and that this influence is strongly correlated to the flow stress: this explains the shape of the K{sub Ic}n K{sub Id} temperature curves as well as the actual magnitude of the strain rate and irradiation effects. Furthermore, CVN crack arrest loads and fracture appearance are also taken advantage of in order to estimate K{sub Ia} degradation. Finally, the CVN-tensile load-temperature diagram

  1. Statistical Analysis of Charpy Transition Temperature Shift in Reactor Pressure Vessel Steels: Application of Nuclear Materials Database(MatDB)

    International Nuclear Information System (INIS)

    The MDPortal contains various technical documents on the degradation and development of nuclear materials. Additionally, the nuclear materials database (MatDB) is also launched in KAERI recently. The MatDB covers the mechanical properties of various nuclear structural materials used as the components: a reactor pressure vessel, steam generator, and primary and secondary piping. In this study, we introduced MatDB briefly, and analyzed the Charpy transition temperature shift in reactor pressure vessel steels of Korean nuclear power plants retrieved from MatDB. It can show an application of the MatDB to the real case of material degradations in NPPs. The MatDB includes the tensile results, Charpy results, fatigue results and J-R curve results at present. In the future other properties such as creep, fracture toughness, and SCC degradations are going to be added consistently. The data from MatDB were successfully applied to estimate the TTS analysis of Korean RPV steels in surveillance tests

  2. Impact property at cryogenic temperature of candidate materials for fusion reactor and their electron beam welded joint

    International Nuclear Information System (INIS)

    Impact properties at cryogenic temperature of candidate materials for fusion reactor and their electron beam welded joints are investigated by using instrumented Charpy impact testing apparatus. Material used are aluminum alloys (A7N01, A5083, A6061), JFMS (Japanese Ferritic Martensitic Steel) and two kinds of high manganese steels. Although JFMS is a steel for high temperature use, the impact test is conducted at low temperature same as the cases of the other materials. Testing results are obtained as follows. 1. Base metals and welded joint of aluminum alloys exhibit high absorbed energy at low temperature. Ductility of each base metal and welded joint gradually decreases with decreasing of testing temperature. 2. Base metal and welded joint of JFMS exhibit an absorbed energy transition temperature at near a room temperature. 3. Base metal and welded joint of high manganese steel A-T (18Mn) exhibit abrupt decreasing of absorbed energy at 77K, but base metal and welded joint of high manganese steel B-T (22Mn-0.2N) exhibit gradual increasing of maximum strength and decreasing of ductility with decreasing of testing temperature. (author)

  3. The effect of needleless electrospun nanofibrous interleaves on mechanical properties of carbon fabrics/epoxy laminates

    OpenAIRE

    Molnar, K.; E. Kostakova; Meszaros, L.

    2014-01-01

    The effect of polyacrylonitrile nanofibrous interlaminar layers on the impact properties of unidirectional and woven carbon fabric (CF)-reinforced epoxy (EP) matrix composites was investigated. The nanofibers were produced directly on the surface of carbon fabrics by a needleless electrospinning method, and composites were then prepared by vacuum-assisted impregnation. Interlaminar shear stress tests, three-point bending, Charpy-impact and instrumented falling weight tests were carried out. T...

  4. Influence of cooling rates on properties of pre-alloyed PM materials

    OpenAIRE

    L.A. Dobrzański; M. Musztyfaga

    2009-01-01

    Purpose: The paper focuses on microstructural and mechanical properties of pre-alloyed Astaloy CrL and CrM sintered steels with high addition of carbon.Design/methodology/approach: The main objective of the present work was to establish the effect of cooling rates on the microstructure and properties such as: Charpy impact test, microhardness, wear resistance (disk on disk test) were evaluated depending on chemical composition. Compacts containing low amounts of chromium, molybdenum and high ...

  5. Effect of Clay Addition on Mechanical Properties of Unsaturated Polyester/Glass Fiber Composites

    OpenAIRE

    Kusmono; Zainal Arifin Mohd Ishak

    2013-01-01

    Unsaturated polyester (UP)/glass fiber/clay composites were prepared by hand layup method. The effect of clay loading on the morphological and mechanical properties of UP/glass fiber composites was investigated in this study. X-ray diffraction (XRD) was used to characterize the structure of the composites. The mechanical properties of the composites were determined by tensile, flexural, unnotched Charpy impact and fracture toughness tests. XRD results indicated that the exfoliated structure w...

  6. 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.

  7. Comparison between instrumented precracked Charpy and compact specimen tests of carbon steels

    International Nuclear Information System (INIS)

    The General Atomic Company High Temperature Gas-Cooled Reactor (HTGR) is housed within a prestressed concrete reactor vessel (PCRV). Various carbon steel structural members serve as closures at penetrations in the vessel. A program of testing and evaluation is underway to determine the need for reference fracture toughness (K/sub IR/) and indexing procedures for these materials as described in Appendix G to Section III, ASME Code for light water reactor steels. The materials of interest are carbon steel forgings (SA508, Class 1) and plates (SA537, Classes 1 and 2) as well as weldments of these steels. The fracture toughness behavior is characterized with instrumented precracked Charpy V-votch specimens (PCVN) - slow-bend and dynamic - and compact specimens (10-mm and 25-mm thicknesses) using both linear elastic (ASTM E399) and elastic-plastic (equivalent Energy and J-Integral) analytical procedures. For the dynamic PCVN tests, force-time traces are analyzed according to the procedures of the Pressure Vessel Research Council (PVRC)/Metal Properties Council (MPC). Testing and analytical procedures are discussed and PCVN results are compared to those obtained with compact specimens

  8. Visual interface for the automation of the instrumented pendulum of Charpy tests used in the surveillance program of reactors vessel of nuclear power plants

    International Nuclear Information System (INIS)

    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)

  9. Properties of Cross-Impact Balance Analysis

    CERN Document Server

    Weimer-Jehle, Wolfgang

    2009-01-01

    CIB matrices are N x N hypermatrices, the elements of which are m x n matrices. They are used in Cross-Impact Balance Analysis, a concept applied in social sciences, management sciences, scenario analysis and technology foresight to identify plausible configurations of qualitatively defined impact networks. Cross-Impact Balance Analysis (CIB) offers an opportunity for qualitative systems analysis without complex mathematics. Although CIB doesn't confront its user with too much mathematics, the background of the method and its algorithm can be scrutinized by mathematical means, thus revealing an extensive set of useful properties which are described and proved in this article. Among them are four laws of invariance, a treatise on several special cases of CIB matrices, and the proof that CIB analysis is equivalent to a universal computer (a Turing machine).

  10. 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.

  11. Impact Property of Ultra Fine Grain Copper

    Directory of Open Access Journals (Sweden)

    Fahad Al-Mufadi

    2014-06-01

    Full Text Available Ultrafine Grained (UFG and Nano-Structured (NS materials have experienced a rapid development during the last decade and made profound impact on every field of materials science and engineering. The present study has been undertaken to develop ultrafine grained pure copper by severe plastic deformation method and to examine the impact property by different characterizing tools. For this aim, equal channel angular pressing die with the channel angle, outer corner angle and channel diameter of 90°, 17° and 20 mm, respectively had been designed and manufactured. Commercial pure copper billets were ECAPed up to four passes by route BC at the ambient temperature. The results indicated that there is a great improvement at the hardness measurement, yield strength and ultimate tensile strength after ECAP process. It is found that the magnitudes of HV reach 136 from 52 HV after the final pass. Also, about 285 and 125% enhancement at the YS and UTS values have been obtained after the fourth pass as compared to the as-received conditions, respectively. On the other hand, the elongation to failure and impact energy have been reduced by imposing ECAP process and pass numbers. It is needed to say that about 56% reductions in the impact energy have been attained for the samples as contrasted to annealed specimens. Furthermore, the grain size of the final pass is 800 nm for Cu sample. Finally, fracture surfaces of billets after impact test have been investigated using Scanning Electron Microscope (SEM.

  12. 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)

  13. Use of precracked Charpy and smaller specimens to establish the master curve

    International Nuclear Information System (INIS)

    The current provisions used in the U.S. Code of Federal Regulations for the determination of the fracture toughness of reactor pressure vessel steels employs an assumption that there is a direct correlation between KIc lower-bound toughness and the Charpy V-notch transition curve. Such correlations are subject to scatter from both approaches which weakens the reliability of fracture mechanics-based analyses. In this study, precracked Charpy and smaller size specimens are used in three-point static bend testing to develop fracture mechanics based Kk values. The testing is performed under carefully controlled conditions such that the values can be used to predict the fracture toughness performance of large specimens. The concept of a universal transition curve (master curve) is applied. Data scatter that is characteristic of commercial grade steels and their weldments is handled by Weibull statistical modeling. The master curve is developed to describe the median KJc fracture toughness for 1T size compact specimens. Size effects are modeled using weakest-link theory and are studied for different specimen geometries. It is shown that precracked Charpy specimens when tested within their confined validity limits follow the weakest-link size-adjustment trend and predict the fracture toughness of larger specimens. Specimens of smaller than Charpy sizes (5 mm thick) exhibit some disparities in results relative to weakest-link size adjustment prediction suggesting that application of such adjustment to very small specimens may have some limitations

  14. Laser weld reconstitution of conventional Charpy and Miniaturized Notch Test (MNT) specimens

    International Nuclear Information System (INIS)

    As nuclear power plants approach end-of-license (EOL) and consideration is given to license renewal, there is an ever increasing need to expand the amount of data obtainable from the original surveillance specimens. A laser welding technique to reconstitute broken Charpy specimens is being developed to produce both conventional and miniaturized Charpy specimens. This paper reports on early laser welding development efforts and summarizes previous proof-of-principle experiments on a 1/16 scale miniaturized Charpy test. In order to benchmark the laser welding procedure, the laser-reconstituted specimen data have been compared with the original specimen data. In addition, the microstructure after welding has been examined to ensure that the material in the vicinity of the notch is essentially unchanged after the welding process. Data which characterize the thermal transient during welding are obtained by attaching thermocouples to the specimens. Other important considerations include perturbation of the stress field near the notch, dynamic stress waves, and contact of the weld region with the tup. Precise control of welding parameters has been demonstrated, heat-affected zones as small as 0.25 mm can be achieved, and sufficient penetration depth can be obtained to enable welding thick sections (1T or greater) to yield conventional Charpy specimens or fracture toughness specimens and thin sections (∼5 mm) to yield Miniaturized Notch Test (MNT) specimens

  15. 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.

  16. The effect of temper embrittlement on the fracture properties of a pressure vessel steel

    International Nuclear Information System (INIS)

    This paper describes an experimental investigation to determine the effects of temper embrittlement on the fracture properties of a 3.5NiCrMoV pressure vessel steel. An extensive test programme involving large and small specimen fracture tests was conducted on material both before and after an embrittling process. The small specimen tests included impact and slow bend tests on both V notched and fatigue cracked charpy specimens. The results obtained from the various small scale tests were then compared against valid Ksub(Ic) results. It was concluded that temper embrittlement of 3.5 NiCrMoV steel is a strain rate sensitive phenomenon and therefore the shift in the fracture toughness transition curve cannot be determined from the corresponding shift in the charpy impact transition curve. (orig.)

  17. Numerical simulation of a Charpy test and correlation of fracture toughness with fracture energy. Vessel steel and duplex stainless steel of the primary loop

    International Nuclear Information System (INIS)

    The analysis methods used to evaluate the harmlessness of defects in the components of the primary coolant circuit of pressurized water reactor are based on the knowledge of the failure properties of concerned materials. The toughness is used to be measured through tests performed on normalized samples. But in some cases, especially for the vessel steel submitted to irradiation effects or for cast components in duplex stainless steel sensitive to thermal ageing, these measurements are not available on the material aged in operation. Therefore, fracture resistance has been evaluated through Charpy tests. Toughness is thus obtained on the basis of an empirical correlation. To improve these predictions, a modeling of the Charpy test in the framework of the local approach to fracture has been performed, for both materials. For the vessel steel, a complete evaluation of toughness has been achieved on the basis of a bidimensional viscoplastic modeling under large strain assumptions and a post-treatment with a Weibull model (cleavage fracture). The main hypothesis (partition between plain stress and plain strain areas in the bidimensional modeling) was corrected after a three dimensional calculations with the finite element program Code-Aster. The fracture analysis put into evidence that damage considerations like cavity nucleation and growth have to be introduced in the model in order to improve the description of physical phenomena. Two ways of progress have been suggested and are in course of being investigated, one in the framework of local approach to failure, the other with the help of micro-macro relationship. With regard to the duplex steel, the description of a Charpy (U) test allowed to clearly discriminate between crack initiation and propagation phases. A modeling through an equivalent homogenous material with a damage law based on a modified Gurson potential enables to describe quantitatively both phases of fracture. It clearly appears that a reliable

  18. Definition of the minimum longitude of insert in the rebuilding of Charpy test tubes for surveillance and life extension of vessels in Mexico

    International Nuclear Information System (INIS)

    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 cm3 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)

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

    OpenAIRE

    Makita A.; Shindo Y.; Ohtsuka N.

    2010-01-01

    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 temperat...

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

    International Nuclear Information System (INIS)

    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

  1. Spring Cleaning: Rural Water Impacts, Valuation and Property Rights Institutions

    OpenAIRE

    Michael Kremer; Jessica Leino; Edward Miguel; Alix Peterson Zwane

    2009-01-01

    In many societies, social norms create common property rights in natural resources, limiting incentives for private investment. This paper uses a randomized evaluation in Kenya to measure the health impacts of investments to improve source water quality through spring protection, estimate the value that households place on spring protection, and simulate the welfare impacts of alternative water property rights norms and institutions, including common property, freehold private property, and a...

  2. 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.

  3. Effect of thermal aging on mechanical properties of cast stainless steels

    International Nuclear Information System (INIS)

    A procedure and correlations are presented for predicting mechanical properties of cast stainless steels in service at temperatures <450 degrees C from known material information. The ''saturation'' fracture properties of a cast stainless steel, i.e., the minimum values that would be achieved for the material after long-term service, are estimated from the chemical composition of the steel. Fracture properties as a function of time and temperature of service are estimated from the kinetics of embrittlement, which are also determined from chemical composition. The correlations successfully predict fracture toughness, Charpy-impact, and tensile properties of cast stainless steels from the Shippingport-, Ringhals-, and Gundremmingen-reactor components

  4. Mechanical properties and fracture toughness of rail steels and thermite welds at low temperature

    Science.gov (United States)

    Wang, Yuan-qing; Zhou, Hui; Shi, Yong-jiu; Feng, Bao-rui

    2012-05-01

    Brittle fracture occurs frequently in rails and thermite welded joints, which intimidates the security and reliability of railway service. Railways in cold regions, such as Qinghai-Tibet Railway, make the problem of brittle fracture in rails even worse. A series of tests such as uniaxial tensile tests, Charpy impact tests, and three-point bending tests were carried out at low temperature to investigate the mechanical properties and fracture toughness of U71Mn and U75V rail steels and their thermite welds. Fracture micromechanisms were analyzed by scanning electron microscopy (SEM) on the fracture surfaces of the tested specimens. The ductility indices (percentage elongation after fracture and percentage reduction of area) and the toughness indices (Charpy impact energy A k and plane-strain fracture toughness K IC) of the two kinds of rail steels and the corresponding thermite welds all decrease as the temperature decreases. The thermite welds are more critical to fracture than the rail steel base metals, as indicated by a higher yield-to-ultimate ratio and a much lower Charpy impact energy. U71Mn rail steel is relatively higher in toughness than U75V, as demonstrated by larger A k and K IC values. Therefore, U71Mn rail steel and the corresponding thermite weld are recommended in railway construction and maintenance in cold regions.

  5. Effects of processing optimisation on microstructure, texture, grain boundary and mechanical properties of Fe–17Cr ferritic stainless steel thick plates

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jian, E-mail: jh595@uowmail.edu.au [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Li, Huijun; Zhu, Zhixiong [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Jiang, Laizhu; Xu, Haigang; Ma, Li [Baoshan Iron and Steel Co., Ltd., Shanghai 200431 (China)

    2014-10-20

    The relationships between microstructure, texture, grain boundary and tensile strength, Charpy impact toughness of (Nb+Ti+V) stabilised Fe–17Cr ferritic stainless steel thick plates were investigated by means of optical microscopy, X-ray diffraction, scanning electron microscopy, electron backscatter diffraction, tensile and Charpy impact testing. The results show that for Fe–17Cr ferritic stainless steel thick plate, the addition of warm rolling procedure leads to refinement of grain size, modification of texture, and then optimisation of grain boundary, including grain boundary character distribution and grain boundary connectivity. Meanwhile, the mechanical testing results indicate that optimal transformation that warm rolling procedure brings to Fe–17Cr ferritic steel thick plate is beneficial to its mechanical properties.

  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. 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.

  8. Residual stress study by neutron diffraction in the Charpy specimens reconstructed by various welding methods

    International Nuclear Information System (INIS)

    The investigation of welding residual stress is very important for nuclear industry since it can considerably affect the structural integrity of various components and products and their lifetime. In order to evaluate the applicability of various welding methods the residual stress in test Charpy specimens welded by various techniques were analysed using high resolution neutron diffraction. The experiments show that the level of residual stress in welds can be quite high and this fact should be considered when choosing an appropriate welding technique. Key words: neutron diffraction, residual stress, welding

  9. Evaluation of Microstructure and Mechanical Properties of Laser Beam Welded AISI 409M Grade Ferritic Stainless Steel%Evaluation of Microstructure and Mechanical Properties of Laser Beam Welded AISI 409M Grade Ferritic Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    A K Lakshminarayanan; V Balasubramanian

    2012-01-01

    The microstructure analysis and mechanical properties evaluation of laser beam welded AISI 409M ferritic stainless steel joints are investigated. Single pass autogeneous welds free of volumetric defects were produced at a welding speed of 3 000 mm/min. The joints were subjected to optical microscope, scanning electron fractographe, microhardness, transverse and longitudinal tensile, bend and charpy impact toughness testing. The coarse ferrite grains in the base metal were changed into dendritic grains as a result of rapid solidification of laser beam welds. Tensile testing indicates overmatching of the weld metal is relative to the base metal. The joints also exhibited acceptable impact toughness and bend strength properties.

  10. The effect of needleless electrospun nanofibrous interleaves on mechanical properties of carbon fabrics/epoxy laminates

    Directory of Open Access Journals (Sweden)

    K. Molnar

    2014-01-01

    Full Text Available The effect of polyacrylonitrile nanofibrous interlaminar layers on the impact properties of unidirectional and woven carbon fabric (CF-reinforced epoxy (EP matrix composites was investigated. The nanofibers were produced directly on the surface of carbon fabrics by a needleless electrospinning method, and composites were then prepared by vacuum-assisted impregnation. Interlaminar shear stress tests, three-point bending, Charpy-impact and instrumented falling weight tests were carried out. The fracture surfaces were analyzed by scanning electron microscopy. Due to the nano-sized reinforcements, the interlaminar shear strength of the woven and unidirectional fiber-reinforced composites was enhanced by 7 and 11%, respectively. In the case of the falling weight impact tests carried out on woven reinforced composites, the nanofibers increased the absorbed energy to maximum force by 64% compared to that measured for the neat composite. The Charpy impact tests indicated that the nanofiber interleaves also led to a significant increase in the initiation and total break energies. Based on the results, it can be concluded that the presence of nanofibers can effectively increase the impact properties of composites without compromising their in-plane properties because the thickness of the composites was not altered by the presence of interleaves. The improvement of the impact properties can be explained by the good load distribution behavior of the nanofibers.

  11. Estimation of sediment properties during benthic impact experiments

    Digital Repository Service at National Institute of Oceanography (India)

    Yamazaki, T.; Sharma, R.

    Sediment properties, such as water content and density, have been used to estimate the dry and wet weights, as well as the volume of sediment recovered and discharged, during benthic impact experiments conducted in the Pacific and Indian Oceans...

  12. 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

  13. Crack lengths calculation by the unloading compliance technique for Charpy size specimens

    International Nuclear Information System (INIS)

    The problems with the crack length determination by the unloading compliance method are well known for Charpy size specimens. The final crack lengths calculated for bent specimens do not fulfil ASTM 1820 accuracy requirements. Therefore some investigations have been performed to resolve this problem. In those studies it was considered that the measured compliance should be corrected for various factors, but satisfying results were not obtained. In the presented work the problem was attacked from the other side, the measured specimen compliance was taken as a correct value and what had to be adjusted was the calculation procedure. On the basis of experimentally obtained compliances of bent specimens and optically measured crack lengths the investigation was carried out. Finally, a calculation procedure enabling accurate crack length calculation up to 5 mm of plastic deflection was developed. Applying the new procedure, out of investigated 238 measured crack lengths, more than 80% of the values fulfilled the ASTM 1820 accuracy requirements, while presently used procedure provided only about 30% of valid results. The newly proposed procedure can be also prospectively used in modified form for specimens of a size different than Charpy size. (orig.)

  14. Predicting the impact of biochar additions on soil hydraulic properties

    Science.gov (United States)

    Different physical and chemical properties of biochar, which is made out of a variety of biomass materials, can impact water movement through amended soil. The objective of this research was to develop a decision support tool predicting the impact of biochar additions on soil saturated hydraulic con...

  15. The Impact of Landfills on Residential Property Values

    OpenAIRE

    Alan K. Reichert; Michael Small; Sunil Mohanty

    1992-01-01

    The purpose of this study is to determine the impact of five municipal landfills on residential property values in a major metropolitan area (Cleveland, Ohio). The study concludes that landfills will likely have an adverse impact upon housing values when the landfill is located within several blocks of an expensive housing area. The negative impact is between 5.5%-7.3% of market value depending upon the actual distance from the landfill. For less expensive, older areas the landfill effect is ...

  16. Analysis of mechanical property data obtained from nuclear pressure vessel surveillance capsules

    International Nuclear Information System (INIS)

    A typical pressure vessel surveillance capsule examination program provides mechanical property data from tensile, Charpy V-notch impact, and, in some cases, fracture mechanics specimens. This data must be analyzed in conjunction with the unirradiated baseline mechanical property data to determine the effect of irradiation on the mechanical properties. In the case of Charpy impact specimens, for example, irradiation typically causes an increase in the transition temperature, and a decrease in the upper shelf energy level. The results of the Charpy impact and other mechanical specimen tests must be evaluated to determine if property changes are occurring in the manner expected when the reactor was put into service. The large amount of data obtained from surveillance capsule examinations in recent years enables one to make fairly good predictions. After the changes in the mechanical properties of specimens from a particular surveillance capsule have been experimentally determined and evaluated, they must be related to the reactor pressure vessel. This requires a knowledge of the neutron fluence of the surveillance capsule, and the ratio of the surveillance capsule fluence to the pressure vessel wall fluence. This ratio is frequently specified by the reactor manufacturer, or can be calculated from a knowledge of the geometry and materials of the reactor components inside the pressure vessel. A knowledge of the exact neutron fluence of the capsule specimens and the capsule to vessel wall neutron fluence ratio is of great importance, since inaccuracies in these numbers cause just as serious a problem as inaccuracies in the mechanical property determinations. A further area causing analysis difficulties is problems encountered in recent capsule programs relating to capsule design, construction, operation, and dismantling. (author)

  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...... generate social issues in multi-titled housing. This appears as a significant gap in the literature, as the tensions inherent in multi-title developments have significant implications for individuals, developments and entire metropolitan areas. This paper employs a lifecycle framework to examine three...... 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. Impact of foundation properties on seismic response

    International Nuclear Information System (INIS)

    Seismic response of the NPP structures depends on the foundation properties twice. First, “free-field excitation” depends on soil/rock layering; second, soil-structure interaction also depends on soil/rock profile. Extreme cases of soil foundation profile are homogeneous half-space and soil layer resting on rigid rock. These two site profiles are principally different in behavior. Each particular site is usually somewhere in between. It is important to know the type of site in order to predict seismic response of NPP structures. (author)

  20. Charpy notch toughness and hardness of reheated martensite and lower bainite

    Directory of Open Access Journals (Sweden)

    F. Vodopivec

    2010-07-01

    Full Text Available A high strength low alloyed (HSLA V-Nb steel was heat treated to martensite and lower bainite with different grain size, reheated for 3 seconds at 750 °C and air cooled. Charpy notch tests were performed from -100 °C to 60 °C and the hardness assessed at room temperature. For as delivered steel and lower bainite, the upper shelf toughness was above 200 J and the transition temperature low, while, for martensite the upper shelf toughness threshold was aproximateky at 0 °C. After reheating, notch toughness was decreased moderatly for martensite and strongly for lower bainite. Independently on grain size, lower bainite was more propensive than martensite to embritlement after short reheating in the (α + β range. For martensite, the change of notch toughness was not related to change of hardness, as by lower hardness lower, also toughness was lower.

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

    International Nuclear Information System (INIS)

    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, T0, 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 KIC curve trends to be over conservative. Replacing RTNDT by the new index, RTTo, in the ASME KIC equation reduces this over conservatism

  2. 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.

  3. Spring cleaning: rural water impacts, valuation, and property rights institutions.

    Science.gov (United States)

    Kremer, Michael; Leino, Jessica; Miguel, Edward; Zwane, Alix Peterson

    2011-01-01

    Using a randomized evaluation in Kenya, we measure health impacts of spring protection, an investment that improves source water quality. We also estimate households' valuation of spring protection and simulate the welfare impacts of alternatives to the current system of common property rights in water, which limits incentives for private investment. Spring infrastructure investments reduce fecal contamination by 66%, but household water quality improves less, due to recontamination. Child diarrhea falls by one quarter. Travel-cost based revealed preference estimates of households' valuations are much smaller than both stated preference valuations and health planners' valuations, and are consistent with models in which the demand for health is highly income elastic. We estimate that private property norms would generate little additional investment while imposing large static costs due to above-marginal-cost pricing, private property would function better at higher income levels or under water scarcity, and alternative institutions could yield Pareto improvements. PMID:21853618

  4. 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

  5. Tube manufacturing and mechanical properties of oxide dispersion strengthened ferritic steel

    International Nuclear Information System (INIS)

    In order to apply the ODS ferritic steels for the prospective cladding materials of advanced fast breeder reactors, fabrication tests of thin-walled cladding tubes were carried out from a viewpoint of future industrial manufacturing. The manufactured claddings within the specification limit exhibited a superior high temperature strength and sufficient Charpy impact properties. The degradation of creep rutpure strength in the bi-axial direction, as compared with the uni-axial direction, is mainly attributed to the grain boundary fracture mode within the elongated bamboo grain structure. (orig.)

  6. Microstructural characterization and mechanical property evaluation of microalloyed steel

    Directory of Open Access Journals (Sweden)

    Om Prakash Tenduwe

    2015-04-01

    Full Text Available Experimental evaluation of microstructural and mechanical property of any material is very important for knowing their serviceability, various properties and behavior in different operational conditions. These parametric properties can be used to predict their proper utilization, life prediction, service reliability and operational safety in various condition. The material used in this investigation is a micro alloyed steel. The micro structural characterizations have been done through optical microscopy as well as SEM and various mechanical property evaluation were done through tensile test, hardness test and Charpy impact toughness tests in different orientations. The results have been used to predict the serviceability, and it is observed from this study that this steel contains good amount of ferrite-pearlite combination, and this material show the high tensile strength and better mechanical property for utilizing in the field of automotive and piping industry.

  7. Applicability of smaller than Charpy specimens for fracture toughness characterization with the VTT method

    International Nuclear Information System (INIS)

    The term fracture toughness usually refers to the linear elastic fracture resistance parameter KIC. In the case of structural steels, the estimation of KIC is limited to the lower shelf of toughness or require extremely large specimens. This specimen size requirement has been one major obstacle for applying fracture mechanics in structural integrity assessment outside aviation, nuclear and off-shore industries. During the last decade, a statistical data treatment methodology, based on a micro-mechanistic cleavage fracture model, combined with elastic plastic finite element analysis has enabled the fracture toughness to be characterized with small specimens in the ductile-to-brittle transition region. The methodology is known as the VTT method or the Master Curve procedure. The development has led to a new testing standard for fracture toughness testing of ferritic steels in the transition range. Here, the premises for the methodology are described and its validity range is discussed. Presently the methodology has been validated for as small as 10.10 mm2 bend specimens, but the use of even smaller specimens is under investigation. Specifically, results obtained with three different sub-Charpy specimen configurations are presented and discussed. (author)

  8. Use of forces from instrumented Charpy V-notch testing to determine crack-arrest toughness

    International Nuclear Information System (INIS)

    The objective of this investigation is an estimation of the crack-arrest toughness, particularly of irradiated materials, from voltage versus time output of an instrumented setup during a test on a Charpy V-notch (CVN) specimen. This voltage versus time trace (which can be converted to force versus displacement) displays events during fracture of the specimen. Various stages of the fracture process can be identified on the trace, including an arrest point indicating arrest of brittle fracture. The force at arrest, Fa, versus test temperature, T, relationship is examined to explore possible relationships to other experimental measures of crack-arrest toughness such as the drop-weight nil-ductility temperature (NDT), or crack-arrest toughness, Ka. For a wide range of weld and plate materials, the temperature at which Fa = 2.45 kN correlates with NDT with a standard deviation, sigma, of about 11 K. Excluding the so-called low upper-shelf energy (USE) welds from the analysis resulted in Fa = 4.12 kN and σ = 6.6 K. The estimates of the correlation of the temperature for Fa = 7.4 kN with the temperature at 100-MPa√m level for a mean American Society of Mechanical Engineers (ASME) type KIa curve through crack-arrest toughness values show that prediction of conservative values of Ka are possible

  9. Re-utilization by '' Stud Welding'' of capsules charpy-V belonged to surveillance programs

    International Nuclear Information System (INIS)

    The perspectives of nuclear plants life extension that are approximating to their end of design life compels to make new surveillance programs. The re-utilization of specimens belonging to surveillance capsules already tested in these new surveillance programs seems be a solution worldwide accepted. The two possible re-utilization processes of this irradiated material are: Subsized specimens and Reconstitution. While the first alternative (Subsized specimens) outlines serious problems for apply the results, the reconstitution eliminates this problem, since the resulting specimens after of the reconstruction procedure would be of the same dimensions that the original. The reconstruction process involves welds, and therefore it has associated the specific problems of this type of joints. Furthermore, by be tried to material irradiated with certain degree of internal damage, that is the variable to evaluate, requires that the heat contribution to the piece not originate local thermal treatments that alter its mechanical qualities. In this work has been followed the evolution by the variables of the weld process and their influence on the quality by the union from metallographic al point of view as well as mechanical for a weld procedure by Stud Welding. The principal objective is to optimize said parameters to assure a good mechanical continuity, without detriment of the microstructural characteristics of the original material. To verify this last have been accomplished with metallographical tests, temperature profile, hardness and will be carried out also Charpy tests. (Author)

  10. 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.

  11. Microstructure and mechanical properties of an oxide dispersion strengthened ferritic steel by a new fabrication route

    International Nuclear Information System (INIS)

    A reduced activation oxide dispersion strengthened (ODS) ferritic steel with nominal composition of Fe-12Cr-2.5W-0.25Ti-0.2V-0.4Y2O3 (designated 12Cr-ODS) was produced by using EDTA-citrate complex method to synthesize and add Y2O3 particles to an argon atomized steel powder, followed by hot isostatic pressing at 1160 deg. C for 3 h under the pressure of 130 MPa, forging at 1150 deg. C, and heat treatment at 1050 deg. C for 2 h. The microstructure, tensile, and Charpy impact properties of the 12Cr-ODS steel were investigated. Transmission electron microscopy studies indicate that the 12Cr-ODS steel exhibits the characteristic ferritic structure containing few dislocations. Tensile characterization has shown that the 12Cr-ODS steel has superior tensile strength accompanied by good elongation at room temperature and 550 deg. C. The material exhibits very attractive Charpy impact properties with upper shelf energy of 22 J and a ductile-to-brittle transition temperature (DBTT) of about -15 deg. C. The formation of small, equiaxed grains and fine dispersion of oxide particles are the main reasons for the good compromise between tensile strength and impact properties.

  12. Coal properties and mine operational factors that impact gas drainage

    Energy Technology Data Exchange (ETDEWEB)

    Black, D.J.; Aziz, N.I. [Wollongong Univ., Wollongong, NSW (Australia)

    2010-07-01

    Areas of increased gas content, which are difficult to drain, are encountered in many underground coal mines in Australia. Several factors have the potential to influence the overall efficiency and effectiveness of gas drainage from the mined coal seam. This paper reported on a study that was conducted at an operating coal mine in the Bulli seam of Australia's Illawarra coal measures. Gas composition in the mining domain ranged from almost pure methane in the east to almost pure carbon dioxide in the west. Gas production data from many inseam gas drainage boreholes was evaluated relative to a variety of coal properties and mine operational factors to determine their impact on gas production performance. The study showed that although the design of the boreholes and the drainage time had some impact on gas production, the coal properties were found to have the greatest impact. In particular, coal rank, ash content, gas content, seam thickness and gas composition all had an influence on gas production. The total gas in place and degree of saturation had the most significant impact on coal seam gas production performance. Several recommendations were made to optimize gas drainage productivity. 3 refs., 12 figs.

  13. Mechanical properties of 1950's vintage 304 stainless steel weldment components after low temperature neutron irradiation

    International Nuclear Information System (INIS)

    The reactor vessels of the nuclear production reactors at the Savannah River Site (SRS) were constructed in the 1950's from Type 304 stainless steel plates welded with Type 308 stainless steel filler using the multipass metal inert gas process. An irradiated mechanical properties database has been developed for the vessel with materials from archival primary coolant system piping irradiated at low temperatures (75 to 150 degrees C) in the State University of New York at Buffalo reactor (UBR) and the High Flux Isotope Reactor (HFIR) to doses of 0.065 to 2.1 dpa. Fracture toughness, tensile, and Charpy-V impact properties of the weldment components (base, weld, and weld heat-affected-zone (HAZ)) have been measured at temperatures of 25 degrees C and 125 degrees C in the L-C and C-L orientations for materials in both the irradiated and unirradiated conditions for companion specimens. Fracture toughness and tensile properties of specimens cut from an SRS reactor vessel sidewall with doses of 0.1 and 0.5 dpa were also measured at temperatures of 25 and 125 degrees C. The irradiated materials exhibit hardening with loss of work hardenability and a reduction in toughness relative to the unirradiated materials. The HFIR-irradiated materials show an increase in yield strength between about 20% and 190% with a concomitant tensile strength increase between about 15% to 30%. The elastic-plastic fracture toughness parameters and Charpy-V energy absorption both decrease and show only a slight sensitivity to dose. The irradiation-induced decrease in the elastic-plastic fracture toughness (Jdef at 1 mm crack extension) is between 20% to 65%; the range of J1C values are 72.8 to 366 kJ/m2 for the irradiated materials. Similarly, Charpy V-notch results show a 40% to 60% decrease in impact energies

  14. 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.

  15. Impact of aging conditions on mechanical properties of thermoplastic polyurethane

    International Nuclear Information System (INIS)

    In this study, impact of environmental aging conditions on the mechanical properties of thermoplastic polyurethane (TPU) was investigated. Especially, effect of temperature on water diffusion has been studied. Water-sorption experiments, tensile test and dynamic mechanical thermal analysis (DMTA) were performed after immersion in distilled water at different temperatures (25, 70 and 90 oC). The sorption process was analyzed by gravimetric measurements at different temperatures. Also, diffusion coefficients of solvent molecules in the TPU samples were identified. Therefore the activation energy and the mixing enthalpy were deduced. The aging impact on some mechanical properties of this material has been investigated after various aging cycles. Degradation of mechanical properties was observed. In fact, elastic modulus and stress at 200% of strain were decreased. It was also shown that such degradation largely depends on both aging temperature and aging immersion duration. The storage modulus (E') was also affected by the hygrothermal (HT) environment. The modification of mechanical properties seems to be well correlated to structural observations obtained from scanning electron microscopy (SEM) photographs. Finally, through thermal aging experiments, it was deduced that the combination of temperature with water seems to be a major factor of TPU degradation.

  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. Impact properties of shear thickening fluid impregnated foams

    Science.gov (United States)

    Soutrenon, M.; Michaud, V.

    2014-03-01

    Concentrated colloidal suspensions of silica particles in polyethylene glycol exhibit a shear thickening behavior: above a critical shear rate in a confined environment, they show a steep increase of viscosity. This reversible transition from a low to a high viscosity state is associated with a large energy absorption that could be harnessed for impact protection. As these suspensions are liquid at rest, however, shear thickening fluids (STFs) are difficult to use in practical applications. Furthermore, their specific rheological properties exist within a narrow range of concentration, so they tend to disappear when the material is in contact with air and humidity. In this work, a soft foam scaffold was impregnated with STF to provide a three-dimensional shape to the assembly at rest, while a silicone was cast around it to serve as a physical barrier to the external environment. A method to quickly impregnate the foam was proposed. Impact tests were carried out on the STF/foam/silicone composite pads using a free fall impact tower. Compared to rubber or pure silicone, larger energy absorptions, up to 85%, were observed, which could be repeated for multiple impacts. The transmitted shock waves were also reduced, showing the potential of this system for impact protection of structures.

  18. Impact properties of shear thickening fluid impregnated foams

    International Nuclear Information System (INIS)

    Concentrated colloidal suspensions of silica particles in polyethylene glycol exhibit a shear thickening behavior: above a critical shear rate in a confined environment, they show a steep increase of viscosity. This reversible transition from a low to a high viscosity state is associated with a large energy absorption that could be harnessed for impact protection. As these suspensions are liquid at rest, however, shear thickening fluids (STFs) are difficult to use in practical applications. Furthermore, their specific rheological properties exist within a narrow range of concentration, so they tend to disappear when the material is in contact with air and humidity. In this work, a soft foam scaffold was impregnated with STF to provide a three-dimensional shape to the assembly at rest, while a silicone was cast around it to serve as a physical barrier to the external environment. A method to quickly impregnate the foam was proposed. Impact tests were carried out on the STF/foam/silicone composite pads using a free fall impact tower. Compared to rubber or pure silicone, larger energy absorptions, up to 85%, were observed, which could be repeated for multiple impacts. The transmitted shock waves were also reduced, showing the potential of this system for impact protection of structures. (paper)

  19. 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.

  20. Effect of Impact Energy on the Impact-Wear Properties of High Manganese Steels in Acidic Corrosive Conditions

    International Nuclear Information System (INIS)

    The impact abrasion behavior of high manganese steel is investigated under three kinds of impact energy in acid hematite ore slurry by using a modified MLD-10 impact abrasion tester. Through the SEM observation of the worn surface and the optical metallographic analysis of the cross-sectional samples, the corrosive impact abrasion mechanisms of the steel under different impact energies are studied. In acid-hematite slurry, the variations of impact energies would result in synchronous transformation of the impact abrasion properties and mechanisms of the high manganese steel in the corrosive condition, as led different corrosive impact abrasion mechanism under different impact energies

  1. Effect of copper content on the microstructure and mechanical properties of multipass MMA, low alloy steel weld metal deposits

    International Nuclear Information System (INIS)

    Effect of copper content in the range of 0.14-0.94 wt.% on the microstructure and mechanical properties of Cr-Ni-Cu low alloy steel weld metal deposits was investigated. All welds were prepared by manual metal arc welding technique in flat position. Microstructure of the welds was examined by optical and scanning electron microscopes. The results showed increase in acicular ferrite and microphases formed at the expense of primary ferrite and ferrite with second phase with steady refinement of microstructure. According to these microstructural changes, hardness, yield and ultimate tensile stresses increased while Charpy V-notch impact toughness and percent elongation reduced.

  2. Impact of Foliage Surface Properties on Vegetation Reflection and Absorption

    Science.gov (United States)

    Yang, B.; Knyazikhin, Y.; Yan, L.; Zhao, Y.; Jiao, J.

    2013-12-01

    Optical properties of phytoelements and their distribution in the canopy space (i.e., canopy structure) are among key factors that determine light environment in vegetation canopies, which in turn drives various physiological and physical processes required for the functioning of plants. Canopy radiative response is the source of information about ecosystem properties from remote sensing. Understanding of how radiation interacts with foliage and traverses in the 3D vegetation canopy is essential to both modeling and remote sensing communities. Radiation scattered by a leaf includes information from two dissimilar sources - the leaf surface and leaf interior. The first component of scattered radiation emanates from light reflected at the air-cuticle interface. This portion of reflected radiation does not interact with biochemical constituents inside the leaf and depends on the properties of the leaf surface. The leaf cuticle acts as a "barrier" for photons to enter the mesophyll and be absorbed; thus, tending to increase the leaf scattering. The second component mainly results from radiation interactions within the leaf-interior. The canopy radiation regime is sensitive to canopy structure, leaf surface properties and leaf biochemical constituents. Impact of leaf surface properties on canopy reflection and absorption is poorly understood. Radiation scattered at the surface of leaves is partly polarized. Fresnel reflection is the principal cause of light polarization. Polarization measurements provide a means to assess the impact of leaf surface properties on canopy radiation regime. We measured Bidirectional Reflectance Factor (BRF) in the principal plane and its polarized portion of needles and shoots of two coniferous species in the 400 to 1000 nm spectral interval. The needle and shoot BRF spectra were decomposed into polarized (PBRF) and diffuse (DBRF) components: BRF=PBRF+DBRF. Our analyses indicate: 1) PBRF in forward directions can account for up to 70% of

  3. Wide – Ranging Influence of Mischmetal on Properties of GP240GH Cast Steel

    Directory of Open Access Journals (Sweden)

    J. Kasińska

    2012-12-01

    Full Text Available This paper presents influence of rare earth metals (REM on the properties of GP240GH cast carbon steel. The research has beenperformed on successive industrial melts. Each time ca 2000 kg of liquid metal was modified. The rare earth metals were put into the ladle during tapping of heat melt from the furnace. Because of this the amount of sulphur in the cast steel was decreased and the non-metallic inclusion morphology was significantly changed. It was found that non metallic inclusions the cracking mechanism of Charpy specimens and the impact strength were all changed. The following properties were tested: mechanical properties (y, UTS, plastic properties (necking, elongation and impact strength (SCI. In the three-point bend test the KJC stress intensity factor was evaluated.

  4. Tensile and impact properties of TZM and Mo-5% Re

    International Nuclear Information System (INIS)

    Some aspects of the mechanical behaviour of two molybdenum alloys, one belonging to the precipitation hardened sub-family (TZM) and the other is a solid solution Mo 5% rhenium-bearing alloy, have been investigated. Experimental data (tensile mechanical strength, ductility and impact properties of unirradiated materials) show that a difference in behaviour exists between the precipitation hardened and the solid solution strengthened alloy, but at the same time a serious discrepancy has been found between the present results and previously reported ductile to brittle transition temperature values for Mo alloys. ((orig.))

  5. Mechanical properties of neutron irradiated vanadium alloys under liquid sodium environment

    International Nuclear Information System (INIS)

    Full text of publication follows: Vanadium alloys are candidate materials for fusion reactor blanket structural materials, but its knowledge about the mechanical properties at high temperatures during neutron irradiation is limited and there are uncertainties that may have influenced the results such as the interstitial impurity content of specimens. The objective of this study is to investigate the mechanical properties and microstructural changes of the high-purified V-4Cr-4Ti alloys, NIFS-HEAT2 during neutron irradiation. In this study, tensile test, Charpy impact test and microstructural observation were done for V-4Cr-4Ti alloys and vanadium binary alloys. Small sized tensile specimens, 1.5 Charpy V-notched specimens and TEM specimens of highly purified V-4Cr-4Ti alloys, NIFS-Heat and vanadium binary alloys were irradiated in Joyo in the temperature range from 450 deg. C to 650 deg. C with a damage level from 1 to 5 dpa. In the irradiation experiment, we have developed Na-enclosed irradiation rig in Joyo in order to equalize the irradiation temperature of large scale specimens and prevent the invasion of interstitial impurities from the circumstance in irradiation rig during irradiation for irradiation specimens. After dismantling the Na-enclosed capsule and cleaning the surface of specimens, tensile tests at room temperature, Charpy impact tests and TEM observation were performed. Irradiation hardening and reduction of ductility for NIFS-Heat alloys could be seen at 450 deg. C irradiation in tensile tests, but the destructive loss of plasticity could not be in any vanadium specimens even at 450 deg. C irradiation. Results of Charpy impact test showed that the amounts of upper shelf energy of NIFS-heat specimens irradiated at 450 deg. C and 600 deg. C were about 0.1-0.2 J at room temperature and brittle behavior could not be seen from load displacement relationship and SEM observation of fracture surface. From the TEM observation of NIFS-Heat alloys

  6. 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.

  7. 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.

  8. 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.

  9. Effect of initial microstructure on mechanical properties in warm caliber rolling of high carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Y.S. [National Research Laboratory for Computer Aided Materials Processing, Department of Mechanical Engineering, KAIST, 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Son, I.H. [Wire Rod Research Group, Technical Research Laboratories, POSCO, 1 Goedong-dong, Nam-gu, Pohang, Gyeongbuk 790-785 (Korea, Republic of); Jung, K.H.; Kim, D.K. [National Research Laboratory for Computer Aided Materials Processing, Department of Mechanical Engineering, KAIST, 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Lee, D.L. [Wire Rod Research Group, Technical Research Laboratories, POSCO, 1 Goedong-dong, Nam-gu, Pohang, Gyeongbuk 790-785 (Korea, Republic of); Im, Y.T., E-mail: ytim@kaist.ac.kr [National Research Laboratory for Computer Aided Materials Processing, Department of Mechanical Engineering, KAIST, 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2011-07-15

    Highlights: {yields} The effect of initial microstructure on change of micro-hardness, tension, and Charpy tests were investigated by warm caliber rolling (WCR). {yields} Smaller ferrite grain and dispersed cementite particles with smaller interspacing increased the strength and toughness. {yields} In WCR, elongation hardly decreased compared to the conventional hot rolling. {yields} Depending on the microstructure change, WCR guaranteed higher impact energy and the mode of fracture varied as well. - Abstract: In this study, the effect of initial microstructure on change of mechanical properties was investigated by warm caliber rolling (WCR) of high carbon steel. Experiments were carried out with two different kinds of initial microstructures of pearlite and tempered martensite at the temperature of 500 deg. C. For comparison, the microstructure of austenite phase obtained from the conventional hot rolling at the temperature of 900 deg. C up to about 83% of the accumulative reduction in area was assumed to be a reference case. It was found that the WCR provided better mechanical properties in terms of strength and toughness compared to the conventional hot rolling based on experimental results of micro-hardness, tension, and Charpy impact tests. The improvement of strength and toughness was attributed to smaller ferrite grain and dispersed cementite particles with smaller interspacing aligned to the rolling direction after the WCR owing to field emission scanning electron microscopy. The investigated WCR might be useful in obtaining the high strength material with better toughness without adding new alloying elements for industrial applications according to the present investigation.

  10. Correlation of microstructure and fracture properties of API X70 pipeline steels

    Science.gov (United States)

    Hwang, Byoungchul; Kim, Young Min; Lee, Sunghak; Kim, Nack J.; Ahn, Seong Soo

    2005-03-01

    Effects of microstructure on fracture toughness and transition temperature of high-toughness X70 pipeline steels were investigated in this study. Three types of steels were fabricated by varying alloying elements such as C, Cu, and Mo, and their microstructures were varied by rolling conditions such as finish rolling temperature and finish cooling temperature. Charpy V-notch (CVN) impact tests and pressed notch drop-weight tear tests (DWTT) were conducted on the rolled steel specimens. The charpy impact test results indicated that the specimens rolled in the single-phase region of the steel containing a reduced amount of C and Mo had the highest upper shelf energy (USE) and the lowest energy transition temperature (ETT) because of the appropriate formation of acicular, quasipolygonal, or polygonal ferrite and the decreased fraction of martensite-austenite constituents. Most of the specimens rolled in the single-phase region also showed excellent DWTT properties as the percent shear area (pct SA) well exceeded 85 pct, irrespective of finish cooling temperatures, while their USE was higher than that of the specimens rolled in the two-phase region. Thus, overall fracture properties of the specimens rolled in the single-phase region were better than those of the specimens rolled in the two-phase region, considering both USE and pct SA.

  11. Effect of initial microstructure on mechanical properties in warm caliber rolling of high carbon steel

    International Nuclear Information System (INIS)

    Highlights: → The effect of initial microstructure on change of micro-hardness, tension, and Charpy tests were investigated by warm caliber rolling (WCR). → Smaller ferrite grain and dispersed cementite particles with smaller interspacing increased the strength and toughness. → In WCR, elongation hardly decreased compared to the conventional hot rolling. → Depending on the microstructure change, WCR guaranteed higher impact energy and the mode of fracture varied as well. - Abstract: In this study, the effect of initial microstructure on change of mechanical properties was investigated by warm caliber rolling (WCR) of high carbon steel. Experiments were carried out with two different kinds of initial microstructures of pearlite and tempered martensite at the temperature of 500 deg. C. For comparison, the microstructure of austenite phase obtained from the conventional hot rolling at the temperature of 900 deg. C up to about 83% of the accumulative reduction in area was assumed to be a reference case. It was found that the WCR provided better mechanical properties in terms of strength and toughness compared to the conventional hot rolling based on experimental results of micro-hardness, tension, and Charpy impact tests. The improvement of strength and toughness was attributed to smaller ferrite grain and dispersed cementite particles with smaller interspacing aligned to the rolling direction after the WCR owing to field emission scanning electron microscopy. The investigated WCR might be useful in obtaining the high strength material with better toughness without adding new alloying elements for industrial applications according to the present investigation.

  12. Effect of multiple repairs in girth welds of pipelines on the mechanical properties

    International Nuclear Information System (INIS)

    This work presents the results of multiple weld repairs in the same area in seamless API X-52 microalloyed steel pipe. Four conditions of shielded metal arc welding repairs and one as-welded specimen of the girth weld were characterized to determine changes in the microstructure, grain size in the heat affected zone, and to evaluate their effect on the mechanical properties of the weld joints. The mechanical properties by means of tension tests, Charpy-V impact resistance and Vickers hardness of the welds were analyzed. The results indicate that significant changes are not generated in the microstructural constituents of the heat affected zone. Grain growth in the heat affected zone at the specimen mid-thickness with the number of repairs was observed. Tensile strength of the weld joints meets the requirement of the API 1104 standard even after the fourth weld repair. Significant reduction in Charpy-V impact resistance with the number of weld repairs was found when the notch location was in the intersection of the fusion line with the specimen mid-thickness. A significant increase in the Vickers hardness of the heat affected zone occurred after the first repair and a gradual decrease in the Vickers hardness occurred as the number of repairs increases

  13. Effect of thermo-mechanical treatments on the microstructure and mechanical properties of an ODS ferritic steel

    International Nuclear Information System (INIS)

    The Fe-14Cr-2W-0.3Ti-0.3Y2O3 oxide dispersion strengthened (ODS) reduced activation ferritic (RAF) steel was fabricated by mechanical alloying of a pre-alloyed, gas atomised powder with yttria nano-particles, followed by hot isostatic pressing and thermo-mechanical treatments (TMTs). Two kinds of TMT were applied: (i) hot pressing, or (ii) hot rolling, both followed by annealing in vacuum at 850 deg. C. The use of a thermo-mechanical treatment was found to yield strong improvement in the microstructure and mechanical properties of the ODS RAF steel. In particular, hot pressing leads to microstructure refinement, equiaxed grains without texture, and an improvement in Charpy impact properties, especially in terms of the upper shelf energy (about 4.5 J). Hot rolling leads to elongated grains in the rolling direction, with a grain size ratio of 6:1, higher tensile strength and reasonable ductility up to 750 deg. C, and better Charpy impact properties, especially in terms of the ductile-to-brittle transition temperature (about 55 deg. C).

  14. 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.

  15. Impact strength of the 28 CDV 508 steel, evolution of the specifications. Metallurgical consequences for relaxation and creep properties

    International Nuclear Information System (INIS)

    The property for use aimed at the beginning of Cr-Mo-V steel manufacturing was its relaxation and creep properties. In that field, all studies show the vanadium carbide as the main element for creep strength; the best efficiency being obtained with a precipitation made during the γ→α transformation of cooling in the bainitic range. The other convenient factors to obtain a high creep strength are a high austenitizing temperature to dissolve all cabide before quenching and also a high room strength level. The combination of these different conditions is practically found in the 28 CDV 508 steel specification as it appears in AFNOR-Standard. Yet the extended use of bolting in a range of temperatures between 450 and 550 deg C produces an additional steel embrittlement. It has more or less harmful consequences for materials specially in transient periods before opening and after closing the turbine for inspection. Bearing in mind the assumption according to which, in bolting, a comparatively high Charpy V level at 0 deg C, as for example 7 daJ/cm2 can be beneficial to secure a transition temperature of steel after use at not higher than room temperatures, the scope of the mork is to determine the metallurgical conditions to perform this purpose and the consequences for relaxation and creep properties of steel

  16. Prediction of quenched and tempered steel and cast steel properties

    Directory of Open Access Journals (Sweden)

    B. Smoljan

    2011-12-01

    Full Text Available Purpose: The influence of processing parameters, such as pouring temperature and cooling rate during the casting, as well as application of hot working and pre-heat treatment, on strength and toughness of quenched and tempered steel was investigated.Design/methodology/approach: Strength and toughness were presented by yield strength and Charpy-V notch toughness, respectively. Experimental procedure of material properties optimization was done using the 25-2 factor experiment.Findings: It was found out that yield strength is insensitive on differences between applied manufacturing processes, but by application of hot working and with appropriate pouring temperature the Charpy-V notch toughness is increased. Also, Charpy-V notch toughness is increased by interactive effect of the appropriate cooling rate during the casting and application of hot working.Research limitations/implications: The research was focused mainly on Charpy-V notch toughness of carbon and low alloyed heat treatable steels.Practical implications: The established algorithms can be used for prediction of tensile strength, yield strength and Charpy-V notch toughness in heat treating practice.Originality/value: Original relation for prediction of quenched and tempered steel and cast steel Charpy-V notch toughness are developed.

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  18. 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

  19. Experimental study on mechanical properties and impact toughness of steel for transmission line towers at low temperatures%输电线铁塔钢材的低温力学和冲击韧性试验

    Institute of Scientific and Technical Information of China (English)

    王元清; 廖小伟; 张子富; 刘希月; 邢海军

    2015-01-01

    为选择合适的输电线铁塔钢材,防止杆塔因构件发生低温脆性断裂引起的破坏,通过系列室温和低温条件下的单轴拉伸和冲击试验,研究了输电线铁塔用Q345B、Q420B、Q460C钢管和Q345B、Q420B角钢钢材的力学性能和冲击韧性;通过对比分析,评价了钢管和角钢钢材的塑性指标;利用Boltzmann函数曲线拟合,得到了钢管和角钢钢材的韧-脆转变温度.结果表明:钢材的屈服强度和抗拉强度随温度的降低而增大,其塑性指标均能满足规范要求;钢材夏比冲击功值随温度降低而减小, Q345B钢管和角钢钢材的韧脆转变温度较高,抗低温冷脆性能较差,结合拉伸和冲击试验结果,建议在寒冷地区优先采用Q420B钢管,不宜采用Q345B角钢.%In cold region, it is of great significance to select suitable steel material in order to prevent the failure or collapse of transmission line tower, which results from the brittle fracture of construction member at low temperatures . A series of uniaxial tensile tests and Charpy impact tests were performed to investigate the mechanical properties and impact toughness of materials of steel tube ( Q345B, Q420B, Q460C ) and angle iron ( Q345B, Q420B) . The plastic indices of steel tube and angle iron materials were evaluated through comparison and analysis. The Boltzmann function was employed to conduct curve fitting for impact energy versus temperature, obtaining the ductile-brittle transition temperatures. Results indicate that the yield strength and ultimate tensile strength increase with the decrease of temperature, and all the plastic indices can meet the prescribed requirement. Charpy impact energy increases as the temperature reduces. Besides, the ductile-brittle transition temperatures of Q345B steel tube and Q345B angle iron are relatively high, indicating the poor resistance ability of cold brittleness failure. Based on the results of tensile tests and impact tests, it is suggested that

  20. Preparation of Esterified Bacterial Cellulose for Improved Mechanical Properties and the Microstructure of Isotactic Polypropylene/Bacterial Cellulose Composites

    Directory of Open Access Journals (Sweden)

    Bo Wang

    2016-04-01

    Full Text Available Bacterial cellulose (BC has great potential to be used as a new filler to reinforce isotactic polypropylene (iPP due to its high crystallinity, biodegradability, and efficient mechanical properties. In this study, esterification was used to modify BC, which improved the surface compatibility of the iPP and BC. The results indicated that the cellulose octoate (CO changed the surface properties from hydrophilic to lipophilic. Compared to the pure iPP, the tensile strength, charpy notched impact strength, and tensile modulus of the iPP/BC composites increased by 9.9%, 7.77%, and 15.64%, respectively. However, the addition of CO reinforced the iPP/CO composites. The tensile strength, charpy notched impact strength, and tensile modulus of the iPP/CO composites increased by 14.23%, 14.08%, and 17.82% compared to the pure iPP. However, the elongation at break of both the composites is decreased. The SEM photographs and particle size distribution of the composites showed improvements when the change of polarity of the BC surface, interface compatibility, and dispersion of iPP improved.

  1. 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.

  2. Evaluation of the mechanical properties of Niobium modified cast AISI H 13 hot work tool steel

    International Nuclear Information System (INIS)

    In this research, the effects of partially replacing of vanadium and molybdenum with niobium on the mechanical properties of AISIH 13 hot-work tool steel have been studied. Cast samples made of the modified new steel were homogenized and austenitized at different conditions, followed by tempering at the specified temperature ranges. Hardness, red hardness, three point bending test and Charpy impact test were carried out to evaluate the mechanical properties together with characterizing the microstructure of the modified steel using scanning electron microscope. The results show that niobium addition modifies the cast structure of Nb-alloyed steel, and increases its maximum hardness. It was found that bending strength; bending strain, impact strength, and red hardness of the modified cast steel are also higher than those of the cast H13 steel, and lower than those of the wrought H13 steel.

  3. 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.

  4. Mechanical property and microstructural change by thermal aging of SCS14A cast duplex stainless steel

    International Nuclear Information System (INIS)

    The aging behavior, especially saturation, of JIS SCS14A cast duplex stainless steels was investigated on the basis of the mechanical properties and microstructural changes during accelerated aging at 350 oC and 400 oC. The aging behavior of the materials mainly proceeds via two stages. During the first stage, the generation and concentration of the iron-rich and chromium-enriched phase in ferrite occurs by phase decomposition. The first stage corresponds to aging times of up to 3000 h at 400 oC. During the first stage, the ferrite hardness achieved is approximately 600 VHN, and the Charpy impact energy is almost saturated. During the second stage, the precipitated chromium-enriched phase aggregates and coarsens, and the G phase precipitation also occurs. The second stage corresponds to the aging times range of 3000-30 000 h at 400 oC. During the second stage, the ferrite hardness achieved is about 800 VHN; however, further hardening exceeding 600 VHN does not influence the Charpy impact energy

  5. Long term aging of duplex stainless steels. Relationship between toughness properties and metallurgical parameters

    International Nuclear Information System (INIS)

    The long term thermal aging behaviour of a whole series of Molybdenum-bearing and Molybdenum-free heats of cast duplex stainless steels has been studied between 300 and 400 deg C. It has been characterized mainly through the evolution of hardness, microhardness of the ferrite, impact Charpy toughness, Charpy-V notch transitions curves and in some cases in term of resistance to ductile tearing with the aim of establishing predictive knowledge from which the behaviour of real components can be assessed. The large data base collected in this extended programme has allowed to show the influence of metallurgical parameters (in particular ferrite, Cr, Ni, Mo contents, ferrite morphology or final solution heat treatment) on mechanical properties in unaged conditions and after aging. For given Cr and ferrite content, Mo-free heats (having also lower nickel content) age considerably less than Mo-bearing heats at 350 deg C, but tend towards the same behaviour at 400 deg C. The analysis of aging kinetics (from the evolution of impact toughness) for Mo-bearing heats (most sensitive to aging) allowed to deduce a set of apparent activation energies which decrease with increasing aging temperature. With this time-temperature equivalence parameter, extrapolations and predictive toughness curves can be given

  6. Analysis of weldment mechanical properties of modified 9 Cr-1 Mo steel

    International Nuclear Information System (INIS)

    The status of welding and weldability studies on modified 9 Cr-1 Mo steel is presented, and microhardness, tensile, creep, and Charpy impact properties of welds made by gas tungsten arc, shielded metal arc, and submerged arc processes are analyzed. Microhardness traverses of modified 9 Cr-1 Mo welds were examined after nominal and extended postweld heat treatments. Microhardness data on modified 9 Cr-1 Mo were also compared with similar results on standard 9 Cr-1 Mo, 2 1/4 Cr-1 Mo, and HT9. Tensile and creep data were primarily on weldment specimens in which the gage length contained the base metal, weld metal, and heat-affected zone. Charpy impact data were primarily on the weld metal, with notch parallel to the welding direction. On the basis of the data presented, it is concluded that standard 9 Cr-1 Mo wire and electrodes can be used to weld modified 9 Cr-1 Mo base metal if welds are given a nominal postweld heat treatment. If welds are to be normalized and tempered, the use of modified wire and electrodes having the base metal composition is recommended

  7. Effects of gamma irradiation and moisture absorption on mechanical properties of PA6/PTFE blends

    Institute of Scientific and Technical Information of China (English)

    罗文波; 肖华明; 谭江华; 吴国忠; 林明丽

    2008-01-01

    PA6/PTFE blends with varying polytetrafluoroethylene content from 3% to 15%(mass fraction) were irradiated by 60Co gamma-ray with various doses(20,50 and 100 kGy) under ambient conditions.Moisture absorption test,U-notched Charpy impact test and quasi-static tension and bending were conducted to investigate the effect of irradiation on moisture absorption and mechanical properties of the blends.It is shown that the exposure of the blend to 60Co irradiation improves the tensile modulus,tensile strength and flexural modulus due to irradiation induced cross-linking in PA6 phase.However,the Charpy impact strength of the blends is much lower than that of the original PA6 and it decreases slightly with the increase of irradiation dose.Moreover,the flexural modulus increases to a maximum value and then decreases with further increasing the PTFE content,and the moisture absorption decreases with the increase of the PTFE content and irradiation dose.

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

    International Nuclear Information System (INIS)

    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

  9. Instrumentation of a Charpy-pendulum. Additional data obtained from it and its application to nuclear reactor pressure vessels surveillance programs

    International Nuclear Information System (INIS)

    Charpy test gives information about a material dynamic fracture behavior. In a plain Charpy test, this information is the absorbed energy during fracture of the specimen, lateral deformation and the percentage of ductile fracture of the specimen. These parameters can then be used for the determination of the material response to a dynamic applied load, and are used at present to determine the brittle-ductile transition temperature of a material. However, there is a lot of additional information that can be obtained from a Charpy test, which is vital for the case of surveillance programs of nuclear power plants, where it is necessary to get the most available information from the specimens to be tested, because each one of them was irradiated for many years under temperature and neutronic flux conditions similar to that of the internal surface of the reactor pressure vessel, which converts these specimens in unique and very expensive ones. This additional information can be obtained from the curve that determines the evolution of the applied force to the specimen throughout the time involved in its fracture. It was possible to instrument a Charpy pendulum at a fraction of the cost necessary to buy an instrumentation package like the ones available in the market, and since the instrumentation equipment obtained is easy to transport. It has the additional advantage that can be used to instrument any other pendulum replacing only the hammer of the pendulum with a instrumented one for that pendulum. (author)

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

    International Nuclear Information System (INIS)

    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

  11. Effect of neutron irradiation on the impact properties of A533B steel

    International Nuclear Information System (INIS)

    A new methodology is proposed to correlate the upper shelf energy (USE) of full size and subsize Charpy specimens of a nuclear reactor pressure vessel plate material, ASTM type A 533 Grade B (A533B) having a low USE (USE 19 n/cm2 (E > 1 MeV) by 78 degree, 83 degree, and 70 degree C for full, half, and third size specimens, respectively. These shifts in DBTT appeared to be independent of specimen size and notch geometry

  12. 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)

  13. 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.

  14. Prediction of Mechanical Properties of 25CrMo48V Seamless Tube Using Neural Network Model

    Science.gov (United States)

    Sun, Laibo; Zhang, Chuanyou; Wang, Qingfeng; Wang, Mingzhi; Yan, Zesheng

    In this investigation, a neural network model was established to predict mechanical properties of 25CrMo48V seamless tubes. The sensitivity analysis was also performed to estimate the relative significance of each chemical composition in mechanical behavior of steel tubes. The results of this investigation show that there is a good agreement between experimental and predicted values indicating desirable validity of the model. Among those alloying elements, the elements of carbon, silicon and chromium tended to play a more important role in controlling both the yielding strength and the Charpy-V-Notch transverse impact toughness. In comparison, the impurities such as O, N, S and P have a relatively weak impact. More detailed dependences of mechanical properties on each chemical composition in isolation can be revealed using the established model. The well-trained neural network has a great potential in designing tough and ultrahigh-strength seamless tubes and modeling the on-line production parameters.

  15. Material properties characterization of low carbon steel using TBW and PWHT techniques in smooth-contoured and U-shaped geometries

    International Nuclear Information System (INIS)

    This paper investigates the effects of the temper bead welding (TBW) technique and post weld heat treatment (PWHT) on mechanical properties of multi-layer welding on low carbon steel specimens using Charpy V-notch impact testing and tensile testing. Several samples of two different weld geometries, viz. (i) smooth-contoured, and (ii) U-shaped were made with multiple bead layers using both TBW and PWHT techniques. Impact testing showed that at room temperature and below, TBW gave an impact toughness in the Heat Affected Zone (HAZ) better than both PWHT and the parent material. At temperatures higher than the room temperature but below 60 °C, PWHT gave better impact toughness in the HAZ. Above 60 °C, both TBW and PWHT showed impact toughness lower than that of the parent material. In tensile testing, both TBW and PWHT weld metal specimens produced acceptable results; however, TBW gave yield and tensile strengths closer to that of the actual material than PWHT. -- Highlights: • Effects of post weld heat treatment (PWHT) and temper bead welding (TBW) on properties are tested. • Charpy V-notch impact and tensile testing was performed on multi-layer welding of low carbon steel. • At room temperature and below, TBW gave better impact toughness than both PWHT and parent material. • Above room temperature but below 60 °C, PWHT gave better impact toughness than TBW. • Above 60 °C, both TBW and PWHT showed impact toughness lower than that of parent material

  16. Aging degradation of cast stainless steels: Effects on mechanical properties

    International Nuclear Information System (INIS)

    A program is being conducted to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water operating conditions. Mechanical property data are presented from Charpy-impact, tensile, and J-R curve tests for several heats of cast stainless steel aged up to 10,000 h at 450, 400, 350, 320, and 2900C. The results indicate that thermal aging increases the tensile strength and decreases the impact energy, J/sub IC/, and tearing modulus of the steels. Also, the ductile-to-brittle transition curve shifts to higher temperatures. The fracture toughness results are consistent with the Charpy-impact data, i.e., the relative reduction in J/sub IC/ is similar to the relative decrease in impact energy. The ferrite content and concentration of C in the steel have a strong effect on the overall process of low-temperature embrittlement. The low-carbon CF-3 steels are the most resistant and Mo-containing CF-8M steels are most susceptible to embrittlement. Weakening of the ferrite/austenite phase boundaries by carbide precipitates has a significant effect on the kinetics and extent of embrittlement of the high-carbon CF-8 and CF-8M steels, particularly after aging at temperatures ≥4000C. The influence of N content and distribution of ferrite on loss of toughness are discussed. The data also indicate that existing correlations do not accurately represent the embrittlement behavior over the temperature range 280 to 4500C, i.e., extrapolation of high-temperature data to reactor temperatures may not be valid for some compositions of cast stainless steel

  17. Efeito do tratamento térmico de solubilização na microestrutura e nas propriedades de impacto do aço inoxidável superaustenítico ASTM A 744 Gr. CN3MN Aging heat treatment effect on the microstructure and impact properties of the super-austenitic stainless steel ASTM A 744 Gr. CN3MN

    Directory of Open Access Journals (Sweden)

    Márcio Ritoni

    2010-03-01

    Full Text Available O aço inoxidável superaustenítico ASTM A 744 Gr. CN3MN é aplicado na fabricação de equipamentos que trabalham em ambientes sob corrosão severa com solicitação mecânica. Nesse trabalho investigou-se a influência do tratamento térmico de solubilização na microestrutura e nas propriedades desse tipo de material. Foram realizados tratamentos térmicos de solubilização na faixa de temperaturas entre 1100 e 1250°C. Ensaios de impacto (Charpy em temperatura ambiente e a -46°C foram realizados nas amostras tratadas termicamente. As análises microestruturais foram feitas por meio de microscopia eletrônica de varredura, eletrônica de transmissão e difração de raios X. Concluiu-se que, para maximizar a resistência ao impacto, a solubilização deve ser feita a 1200°C, pois tal medida produz a menor fração volumétrica de precipitados. As amostras solubilizadas a 1200 e 1240°C apresentaram fase sigma (s e carboneto M6C.This research investigated the influence of solution heat treatments on the microstructure and properties of this type of material. These treatments were carried out at temperatures ranging from 1100 to 1250ºC. Impact (Charpy tests were conducted at room temperature and -46°C for all solution treated samples. The microstructural analyses were carried out by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. It was concluded that, to maximize the material's impact strength, the solution heat treatment should be done at 1200ºC, at which temperature the volumetric fraction of precipitates is lower than at other solution heat treatment temperatures. The samples that were solution heat treated at 1200 and 1240ºC presented sigma (s and M6C carbide phases.

  18. Effects of alloying elements and solution-annealing temperature on the mechanical properties of austenitic Fe-Mn-C alloy

    International Nuclear Information System (INIS)

    In order to investigate the effects of various alloying elements including S as a free-machining element on the mechanical properties of high manganese non-magnetic steel, tensile and Charpy impact tests were carried out in the annealed condition. The mechanism of the observed large strengthening effect of V especially on the 0.2% proof stress was investigated by examining Petch relation and its solution hardening effect. A linear regression equation which relates the 0.2% proof stress to the chemical composition is obtained. The strengthening effect of ferrite-forming substitutional element becomes greater in the order of Cr, Mo and V. Especially, the effect of V on the 0.2% proof stress is comparable with that of interstitial element C. While, austenite-forming substitutional elements Ni and Mn have little effect on the strength. The elongation and Charpy impact toughness show decreasing tendencies by the additions of ferrite-forming substitutional elements and S. However, interstitial elements C and N hardly decrease the elongation irrespective of their large strengthening effect. 0.2% proof stress and tensile strength decrease with increasing solution annealing temperature and a Petch relation is found. The large strengthening effect of V cannot be explained by its small solution hardening effect and is rather considered to be mainly attributable to grain refining by the V addition. (author)

  19. 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.

  20. Mechanical properties of thermally aged cast stainless steels from Shippingport reactor components

    International Nuclear Information System (INIS)

    Thermal embrittlement of static-cast CF-8 stainless steel components from the decommissioned Shippingport reactor has been characterized. Cast stainless steel materials were obtained from four cold-leg check valves, three hot-leg main shutoff valves, and two pump volutes. The actual time-at-temperature for the materials was ∼13 y at ∼281 C (538 F) for the hot-leg components and ∼264 C (507 F) for the cold-leg components. Baseline mechanical properties for as-cast material were determined from tests on either recovery-annealed material, i.e., annealed for 1 h at 550 C and then water quenched, or material from the cooler region of the component. The Shippingport materials show modest decreases in fracture toughness and Charpy-impact properties and a small increase in tensile strength because of relatively low service temperatures and ferrite content of the steel. The procedure and correlations developed at Argonne National Laboratory for estimating mechanical properties of cast stainless steels predict accurate or slightly lower values for Charpy-impact energy, tensile flow stress, fracture toughness J-R curve, and JIC of the materials. The kinetics of thermal embrittlement and degree of embrittlement at saturation, i.e., the minimum impact energy achieved after long-term aging, were established from materials that were aged further in the laboratory. The results were consistent with the estimates. The correlations successfully predicted the mechanical properties of the Ringhals 2 reactor hot and crossover-leg elbows (CF-8M steel) after service of ∼ 15 y and the KRB reactor pump cover plate (CF-8) after ∼ 8 y of service

  1. Superior Properties of Ultra-fine-grained Steels

    Directory of Open Access Journals (Sweden)

    J. I. Leinonen

    2004-01-01

    Full Text Available A description of the improved mechanical properties obtained in ultra-fine-grained steels up to now will be presented in this paper, and some potential applications of these new generation steels will be described. In addition, the principle and implementation of a novel hot rolling process developed by the author will be introduced. This novel Thermomechanical Nonrecrystallisation Control Process (TNCP has been shown to give an ultra-fine ferrite (uff structure with grain sizes of 2 to 3mm in various test steels, thus resulting in super-toughness. Charpy V impact test results suggest that some of these steels could still be tough at temperatures lower than -100 °C. This novel process, TNCP, is one potential candidate for the commercial production of superior ultra-fine-grained steels in the future.

  2. 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.

  3. A study on the structural integrity evaluation of the dual purpose casks for the spent fuel storage and transport with HANARO irradiation impact tests

    International Nuclear Information System (INIS)

    This study is conducted in order to evaluate structural integrity of the dual propose casks for the spent fuel storage and transport after 30 years storage. Charpy impact specimen was manufactured and material irradiation test was performed using the HANARO. For the irradiated and unirradiated Charpy impact specimen with v-notch, the impact test was conducted, then the impact test results were applied in the impact analysis of the dual propose casks for the spent fuel storage and transport. From the impact analysis results, we confirmed that the structural integrity of the dual propose cask was maintained under original and irradiation conditions

  4. 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.

  5. 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.

  6. Effects of post-weld heat treatment on microstructure and mechanical properties of laser welds in GH3535 superalloy

    Science.gov (United States)

    Yu, Kun; Jiang, Zhenguo; Leng, Bin; Li, Chaowen; Chen, Shuangjian; Tao, Wang; Zhou, Xingtai; Li, Zhijun

    2016-07-01

    In this study, the microstructure and mechanical properties of laser welds before and after post-weld heat treatment processes were studied. The results show that the tensile strength of the joints can be increased by 90 MPa by a post-weld heat treatment process at 871 °C for 6 h, exceeding the strength of the original state of the base metal. Besides, elongation of the joints are also increased to 43% by the process, whereas the elongation of as-welded joints are only 22%. In addition, the Charpy impact properties of laser welds almost do not change. Second phase precipitates, which were identified as Mo-Si rich M6C-type carbides by transmission electron diffraction and scanning electron microscope, were observed at solidification grain boundaries and solidification subgrain boundaries. These carbides can pin dislocations during the following tensile deformation, hence are responsible for the strengthening of tensile properties of the joints.

  7. Mechanical properties at cryogenic temperature of improved high manganese steel and their electron beam welded joint

    International Nuclear Information System (INIS)

    This study has been conducted to obtain more improved high manganese steel than A-T and B-T which were investigated in the previous paper. Then, tensile and impact properties at cryogenic temperature of three kinds of high manganese steel, AS (17Mn-12Cr-4.5Si), BV (21Mn-6.3Cr-3.4Si-0.19N) and CT (25Mn-6.5Cr-4.5Si), and their electron beam welded joints were examined by using tensile and instrumented Charpy impact testing apparatus. From the view points of ultimate tensile strength, elongation and total absorbed energy at cryogenic temperature, CT is far better than A-T and B-T, and can be considered as an improved high manganese steel. (author)

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

    International Nuclear Information System (INIS)

    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.

  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. Numerical simulation of a Charpy test and correlation of fracture toughness with fracture energy. Vessel steel and duplex stainless steel of the primary loop; Simulation numerique d`un essai de resilience et correlation entre resilience et proprites de tenacite. Acier de cuve et acier austenoferritique du circuit primaire

    Energy Technology Data Exchange (ETDEWEB)

    Breban, P; Eripret, C. [Departement MTC, Service RNE, Direction des Etudes et Recherches, Electricite de France (EDF), 92 - Clamart (France)

    1995-12-31

    The analysis methods used to evaluate the harmlessness of defects in the components of the primary coolant circuit of pressurized water reactor are based on the knowledge of the failure properties of concerned materials. The toughness is used to be measured through tests performed on normalized samples. But in some cases, especially for the vessel steel submitted to irradiation effects or for cast components in duplex stainless steel sensitive to thermal ageing, these measurements are not available on the material aged in operation. Therefore, fracture resistance has been evaluated through Charpy tests. Toughness is thus obtained on the basis of an empirical correlation. To improve these predictions, a modeling of the Charpy test in the framework of the local approach to fracture has been performed, for both materials. For the vessel steel, a complete evaluation of toughness has been achieved on the basis of a bidimensional viscoplastic modeling under large strain assumptions and a post-treatment with a Weibull model (cleavage fracture). The main hypothesis (partition between plain stress and plain strain areas in the bidimensional modeling) was corrected after a three dimensional calculations with the finite element program Code-Aster. The fracture analysis put into evidence that damage considerations like cavity nucleation and growth have to be introduced in the model in order to improve the description of physical phenomena. Two ways of progress have been suggested and are in course of being investigated, one in the framework of local approach to failure, the other with the help of micro-macro relationship. With regard to the duplex steel, the description of a Charpy (U) test allowed to clearly discriminate between crack initiation and propagation phases. A modeling through an equivalent homogenous material with a damage law based on a modified Gurson potential enables to describe quantitatively both phases of fracture. It clearly appears that a reliable

  11. 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.

  12. Impact of Apple Pomace on the Property of French Bread

    OpenAIRE

    Yaqiang He; Qian Lu

    2015-01-01

    This study analyzed properties of wheat dough and French bread added with different kinds of apple pomace. In the analysis of wheat dough, both farinograph indexes and extenograph indexes were used as evaluation criteria. Specific volume, whiteness and bread core pores were employed to evaluate the property of French bread. Analysis on the nutrient profile of apple pomace indicated that the content of dietary fiber could reach 15.8%. The result of farinograph indexes and extenograph indexes s...

  13. Optical properties of impact diamonds from the Popigai astrobleme

    OpenAIRE

    Yelisseyev, A.; Meng, G. S.; Afanasyev, V.; Pokhilenko, N.; Pustovarov, V.; Isakova, A.; Z. S. Lin; Lin, H. Q.

    2013-01-01

    Impact diamonds from Popigai astrobleme were found to consist of different carbon phases: cubic and hexagonal diamond with sp3 bonding according to X-ray structural analysis as well as amorphous, crystalline and disordered graphite with sp2-bonding (Raman scattering). The sizes of graphite domains vary from 10 to 100 nm. Fundamental absorption edge for Popigai impact diamonds is shifted ~ 0.5 eV to lower energies in comparison with kimberlite diamonds (5.47 eV) as a result of the lonsdaleite ...

  14. Impact of Permeation Properties and Backsheet-Encapsulant Interactions on the Reliability of PV Modules

    OpenAIRE

    Cornelia Peike; Philip Hülsmann; Matthias Blüml; Philipp Schmid; Karl-Anders Weiß; Michael Köhl

    2012-01-01

    The reliability of photovoltaic modules is highly influenced by the material properties of the backsheet and encapsulation material. Currently, little attention is paid to the permeation properties of the back-sheet material or to its impact on encapsulation degradation and module reliability. We investigated the interaction of different types of solar encapsulation and back-sheet materials. Therefore, various laminates were made to examine the environmental impact on such materials during th...

  15. Proceedings of a C.S.N.I. specialist meeting on instrumented pre-cracked Charpy testing

    International Nuclear Information System (INIS)

    This report presents the status of the testing and data analysis procedures for the instrumented pre-cracked Charpy test with emphasis on the application of the test technique to the nuclear industry. The report (Proceedings) consist of invited technical papers by specialists in the field and a synopsis of the comments, conclusions, and recommendations reached in a workshop session. The CSNl-sponsored and EPRI-hosted meeting confirmed both the popularity of the test technique in the nuclear industry and the problems associated with the test technique due to the lack of a national or international consensus standard. Major emphasis in the meeting was devoted to evaluating the existing industry testing procedure (EPRI procedure) and proposed national standards (ASTM, ASK). The EPRI procedures were considered adequate by specialists concerned with engineering applications, but too restrictive by specialists concerned with research applications. As a result of the conference, a compilation of state-of-the-art papers is now available to code and standard committees. Specific comments concerning test and data analysis procedures, applications in the nuclear industry, and future research areas are also contained in the proceedings

  16. Vibration properties of the ostrich eggshell at impact

    Czech Academy of Sciences Publication Activity Database

    Trnka, Jan; Stoklasová, Pavla; Strnková, J.; Nedomová, Š.; Buchar, J.

    2013-01-01

    Roč. 61, č. 6 (2013), s. 1873-1880. ISSN 1211-8516 Institutional support: RVO:61388998 Keywords : eggshell * impact * surface displacement Subject RIV: GM - Food Processing http://acta.mendelu.cz/61/6/1873/same_authors/

  17. Psychometric properties of the impact on participation and autonomy questionnaire.

    NARCIS (Netherlands)

    Cardol, M.; Haan, R.J. de; Jong, B.A. de; Bos, G.A.M. van den; Groot, J.M. de

    2001-01-01

    OBJECTIVE: To examine the homogenity, test-retest reliability, construct validity, and concurrent validity of the Impact on Participation and Autonomy Questionnaire (IPAQ). DESIGN: Cross-sectional study with a test-retest subsample. PATIENTS: One hundred twenty-six persons from 5 diagnostic groups r

  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. Prediction of the brittle fracture toughness value of a RPV steel from the analysis of a limited set of Charpy results

    International Nuclear Information System (INIS)

    Our objective is to establish a method to be able to determine fracture toughness of a reactor pressure vessel (RPV) by using the small number of Charpy specimens used in the reactor surveillance program. Previous studies have shown that it is possible to determine fracture toughness from Charpy tests. Another point is to determine if statistical effects are compatible with a restricted number of specimens, this paper deals with this point and presents a methodology that is applicable to the case of irradiated materials from the surveillance program. Several conclusions can be drawn from this study: -) When determining failure parameters, we gain most accuracy by increasing the number of samples from 3 to about 6; -) it is possible to evaluate brittle fracture toughness using local approach, either by using Beremin or Renevey model; -) The effect of using a small number of Charpy specimens to determine fracture toughness in brittle fracture is evaluated. The error in the evaluation of fracture toughness is much smaller than the experimental dispersion itself. (A.C.)

  20. Influence of Mode of Metal Transfer on Microstructure and Mechanical Properties of Gas Metal Arc-Welded Modified Ferritic Stainless Steel

    Science.gov (United States)

    Mukherjee, Manidipto; Pal, Tapan Kumar

    2012-06-01

    This article describes in detail the effect of the modes of metal transfer on the microstructure and mechanical properties of gas metal arc-welded modified ferritic stainless steel (SSP 409M) sheets (as received) of 4 mm thickness. The welded joints were prepared under three modes of metal transfer, i.e., short-circuit (SC), spray (S), transfer, and mix (M) mode transfer using two different austenitic filler wires (308L and 316L) and shielding gas composition of Ar + 5 pct CO2. The welded joints were evaluated by means of microstructural, hardness, notched tensile strength, Charpy impact toughness, and high cycle fatigue. The dependence of weld metal microstructure on modes of metal transfer and filler wires has been determined by dilution calculation, WRC-1992 diagram, Creq/Nieq ratio, stacking fault energy (SFE), optical microscopy (OM), and transmission electron microscopy (TEM). It was observed that the microstructure as well as the tensile, Charpy impact, and high cycle fatigue of weld metal is significantly affected by the mode of metal transfer and filler wire used. However, the heat-affected zone (HAZ) is affected only by the modes of metal transfer. The results have been correlated with the microstructures of weld and HAZ developed under different modes of metal transfer.

  1. Impact of carbonation on water transport properties of cementitious materials

    International Nuclear Information System (INIS)

    Carbonation is a very well-known cementitious materials pathology. It is the major cause of reinforced concrete structures degradation. It leads to rebar corrosion and consequent concrete cover cracking. In the framework of radioactive waste management, cement-based materials used as building materials for structures or containers would be simultaneously submitted to drying and atmospheric carbonation. Although scientific literature regarding carbonating is vast, it is clearly lacking information about the influence of carbonation on water transport properties. This work then aimed at studying and understanding the change in water transport properties induced by carbonation. Simultaneously, the representativeness of accelerated carbonation (in the laboratory) was also studied. (author)

  2. 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

  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. Psychometric properties of the impact on participation and autonomy questionnaire.

    OpenAIRE

    Cardol, M.; Haan, R.J. de; de Jong, B A; Bos, G.A.M. van den; Groot, J.M. de

    2001-01-01

    OBJECTIVE: To examine the homogenity, test-retest reliability, construct validity, and concurrent validity of the Impact on Participation and Autonomy Questionnaire (IPAQ). DESIGN: Cross-sectional study with a test-retest subsample. PATIENTS: One hundred twenty-six persons from 5 diagnostic groups recruited from the outpatients clinics of 2 rehabilitation centers and the rehabilitation department of an academic hospital. INTERVENTIONS: The IPAQ and 3 other self-administered questionnaires (Si...

  5. 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.

  6. 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.

  7. The Long Term Impact of Flooding on Residential Property Values

    OpenAIRE

    C. Eves

    2001-01-01

    Current planning schemes in Australia identify areas that are potentially flood liable. This identification of flood liable land is based on flood height levels over time. Throughout New South Wales this measure of flood affectation is determined by three classifications. These classifications also influence the development of residential property within these flood areas. Prospective purchasers are advised of this flood zoning when a full title search is carried out. However, as these proper...

  8. Hadron properties in nuclear medium and their impacts on observables

    OpenAIRE

    Tsushima, K.

    2002-01-01

    The effect of changes in hadron properties in a nuclear medium on physical observables is discussed. Highlighted results are, (1) hypernuclei, (2) meosn-nuclear bound states, (3) $K$-meson production in heavy ion collisions, and (4) $J/\\Psi$ dissociation in a nuclear medium. In addition, results for the near-threshold $\\omega$- and $\\phi$-meson productions in proton proton collisions are reported.

  9. Does Size Really Matter? Landfill Scale Impacts on Property Values

    OpenAIRE

    Lim, Jong Seok; Missios, Paul

    2005-01-01

    The economic advantage of constructing and operating large-scale landfills over small-scale landfills has been used to justify regional landfills as a solution to the municipal waste disposal problem. In addition to the dampening effects on social efforts to divert waste away from landfills, higher external costs of larger landfills may in fact offset the private cost advantages. In this study, the negative effects of a landfill that are capitalized in property values of houses located in the...

  10. Cellulose Ester / Polyolefin Binary Blends : Rheology, Morphology and Impact Properties

    OpenAIRE

    Besson, François; Vanhille, Aurélie; Budtova, Tatiana

    2012-01-01

    Due to depletion of fossil resources and global environmental respect awareness, interest in biobased plastic materials is tremendously growing. Direct extraction of vegetal polymers like cellulose followed by a chemical modification to bring new properties is one of the paths to produce a bioplastic. Progressively replaced by oil-based polymers in the sixties, thermoplastic cellulose esters are now reconsidered for various materials applications. To improve mechanical weaknesses of cellulose...

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

    International Nuclear Information System (INIS)

    Highlights: → Polypropylene montmorillonite (PP-MMT) produced at different processing conditions. → Polypropylene Nanocomposites with higher increase on impact resistance. → 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.

  13. 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.

  14. Intellectual Property in Vaccine Innovation: Impact of Recent Patent Developments.

    Science.gov (United States)

    Ng, Elizabeth Siew-Kuan

    2016-01-01

    This chapter examines the issues on patentability of microorganisms and human genes under the US laws and analyzes their influence on vaccine innovation. The analysis will focus on three aspects, namely, the naturally existing state, unmodified isolated form (i.e., mere extraction from the natural environment), and human-modified/genetically engineered structure. The outcome of the assessment suggests that the impact of the recent US patent jurisprudence on vaccines may differ significantly depending on whether the preparation of a vaccine in question involves natural or man-made DNA material. PMID:27076340

  15. Low temperature thermal aging of austenitic stainless steel welds: Kinetics and effects on mechanical properties

    International Nuclear Information System (INIS)

    Highlights: ► Embrittlement of 304L and 316L welds after aging up to 20,000 h. ► Spinodal decomposition and G-phase precipitation in ferrite at 400 °C. Only spinodal decomposition at 335 and 365 °C. ► Charpy impact, microhardness and tensile tests for evaluation of aging embrittlement and its kinetics determined. - Abstract: Austenitic stainless steel welds in components used in light water reactors are susceptible to thermal aging embrittlement at reactor operating temperature of around 300 °C after a long service life. In this study, low temperature aging embrittlement of types 304L and 316L stainless steel welds with 10% ferrite was investigated on the basis of changes in mechanical properties and microstructure after aging up to 20,000 h at 335, 365 and 400 °C. Spinodal decomposition and G-phase precipitation in the ferrite was observed after aging which lead to embrittlement in the material. In contrast to the small effect on tensile properties, the impact toughness was significantly degraded after aging. Charpy impact test of the aged samples showed decrease in upper-shelf and lower-shelf energy and increase in ductile brittle transition temperature. Large increase in the microhardness of ferrite phase was observed with no change in austenite hardness. The embrittlement in 316L weld was higher compared to 304L weld for similar aging condition. The kinetics of aging embrittlement was established based on Arrhenius relationship. A constant activation energy was determined for 304L weld in the temperature range 335–400 °C, however, 316L weld showed different activation energy values in each temperature range.

  16. Low temperature thermal aging of austenitic stainless steel welds: Kinetics and effects on mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, K., E-mail: kchandra@barc.gov.in [Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Kain, Vivekanand [Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Bhutani, Vikas [Punjab Engineering College, Chandigarh 160 012 (India); Raja, V.S. [Indian Institute of Technology, Mumbai 400 076 (India); Tewari, R.; Dey, G.K. [Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Chakravartty, J.K. [Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2012-02-01

    Highlights: Black-Right-Pointing-Pointer Embrittlement of 304L and 316L welds after aging up to 20,000 h. Black-Right-Pointing-Pointer Spinodal decomposition and G-phase precipitation in ferrite at 400 Degree-Sign C. Only spinodal decomposition at 335 and 365 Degree-Sign C. Black-Right-Pointing-Pointer Charpy impact, microhardness and tensile tests for evaluation of aging embrittlement and its kinetics determined. - Abstract: Austenitic stainless steel welds in components used in light water reactors are susceptible to thermal aging embrittlement at reactor operating temperature of around 300 Degree-Sign C after a long service life. In this study, low temperature aging embrittlement of types 304L and 316L stainless steel welds with 10% ferrite was investigated on the basis of changes in mechanical properties and microstructure after aging up to 20,000 h at 335, 365 and 400 Degree-Sign C. Spinodal decomposition and G-phase precipitation in the ferrite was observed after aging which lead to embrittlement in the material. In contrast to the small effect on tensile properties, the impact toughness was significantly degraded after aging. Charpy impact test of the aged samples showed decrease in upper-shelf and lower-shelf energy and increase in ductile brittle transition temperature. Large increase in the microhardness of ferrite phase was observed with no change in austenite hardness. The embrittlement in 316L weld was higher compared to 304L weld for similar aging condition. The kinetics of aging embrittlement was established based on Arrhenius relationship. A constant activation energy was determined for 304L weld in the temperature range 335-400 Degree-Sign C, however, 316L weld showed different activation energy values in each temperature range.

  17. The effect of repeated repair welding on mechanical and corrosion properties of stainless steel 316L

    International Nuclear Information System (INIS)

    Highlights: • Microstructure and properties of the HAZ were analyzed. • Delta ferrite morphology changed, and ferrite content decreased. • Adverse effect on yield and ultimate tensile strength was negligible. • The absorbed energy and hardness decreases with increasing number of weld-repair. • The sensitivity to pitting corrosion was increased. - Abstract: The purpose of this study is to evaluate changes in the mechanical, micro structural and the corrosion properties of stainless steel 316L under repeated repair welding. The welding and the repair welding were conducted by shielded metal arc welding (SMAW). The SMAW welding process was performed using E316L filler metals. Specimen of the base metal and different conditions of shielded metal arc welding repairs were studied by looking in the micro structural changes, the chemical composition of the phases, the grain size (in the heat affected zone) and the effect on the mechanical and corrosion properties. The microstructure was investigated using optical microscopy (OM) and scanning electron microscopy (SEM). The chemical composition of the phases was determined using energy dispersive spectrometry (EDS). The corrosion behavior in 1 M H2SO4 + 3.5% NaCl solution was evaluated using a potentiodynamic polarization method. Tensile tests, Charpy-V impact resistance and Brinell hardness tests were conducted. Hardness of the heat affected zone decreased as the number of repairs increased. Generally an increase in the yield strength (YS) and the ultimate tensile strength (UTS) occurred with welding. After the first repair, a gradual decrease in YS and UTS occurred but the values of YS and UTS were not less than values of the base metal. Significant reduction in Charpy-V impact resistance with the number of weld repairs were observed when the notch location was in the HAZ. The HAZ of welding repair specimen is more sensitive to pitting corrosion. The sensitivity of HAZ to pitting corrosion was increased by

  18. Electron impact polarization and correlation properties of the inert gases

    Energy Technology Data Exchange (ETDEWEB)

    Csanak, G.; Cartwright, D.C. [Los Alamos National Lab., NM (United States); Machado, L.E. [Sao Carlos Univ., SP (Brazil); Meneses, G.D. [Campinas Univ., SP (Brazil)

    1993-08-01

    For the heavier rare-gas targets, Ne, Ar, Kr, there is now a reasonable amount of experimental electron impact coherence parameter data available for excitation of the lowest J = 1 states. Theoretical results for those rare-gas targets have been restricted to distorted-wave approximation (DWA) type theories. A systemization of the experimental data is presented, and they are compared with available theoretical results. In the case of the heavy rare gases, the experimental and theoretical data available for the three species, Ne, Ar, Kr, are compared in order to identify trends. The experimental data are compared with results from available theories (mainly DWA type), and the importance of spin-orbit coupling effects and ``shell`` effects is discussed. A physical picture that is emerging from all collisional data is presented, and future experimental and theoretical activities that will, provide new insight into the physics of these processes are recommended.

  19. 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.

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

    OpenAIRE

    Samarždić, I.; Aračić, S.; Duđner, M.

    2008-01-01

    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.

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

    International Nuclear Information System (INIS)

    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

  2. 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.

  3. Impact of pairing on thermodynamical properties of stellar matter

    Science.gov (United States)

    Burrello, S.; Aymard, F.; Colonna, M.; Gulminelli, F.; Raduta, Ad. R.

    2016-05-01

    Superfluidity in the crust is a key ingredient for the cooling properties of proto-neutron stars. Investigations on crust superfluidity carried out so far typically assumed that the cluster component was given by a single representative nucleus and did not consider the fact that at finite temperature a wide distribution of nuclei is expected to be populated at a given crust pressure condition. We want to assess the importance of this distribution on the calculation of the heat capacity in the inner crust, in the framework of an extended NSE model. We additionally show that it is very important to consider the temperature evolution of the proton fraction, imposed by the β-equilibrium condition, for a quantitatively reliable estimation of the heat capacity.

  4. Impacts of radiation processing on physicochemical properties of Table Eggs

    International Nuclear Information System (INIS)

    This study investigated the effect of gamma irradiation on pathogens, quality, and functional properties of shell eggs. Using intact, fresh while and brown shell eggs, inoculated with 109 colony-forming units (cfu) of S enteritidis and S, typhimurium. The effect of gamma-irradiation at doses 2,4 and 6 kGy of gamma irradiation on bacteriologic and population and physical characteristics (Haugh units and yolk color), chemical composition (moisture, crude protein, crude fat and ash), the rheological changes (viscosity), pH and protean solubility of the eggs were determinate d. Results showed that 2 kGy, the number of S, enteritidis and eggs internal quality as freshness as measured by albumen height and the number of hugh units, and yolk color index were all significantly reduced with increasing irradiation doses. On significant change was found after irradiation in egg white or yolk in the chemical composition (moisture, crude protein, crude fat and ash). After irradiation, the foaming ability and foam capacity of egg white were increasing radiation doses> The viscosity of egg white and yolk decreased with increasing doses of irradiation. The pH of the egg white and yolk increasing doses of radiation dose. The protein salability decreased significantly in egg white and yolk with increasing radiation dose. These Results Suggest that gamma irradiation reduce the freshness of shell eggs and improving important functional properties such as to foaming ability and foaming capacity. Gamma irradiation can also be applied to the egg breaking process sine irradiation reduces the viscosity of egg white and yolk, which can allow egg whites and yolks to be separated with greater efficiency. (Author)

  5. 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. PMID:22751053

  6. Biological Invasions Impact Ecosystem Properties and can Affect Climate Predictions

    Science.gov (United States)

    Gonzalez-Meler, M.; Matamala, R.; Cook, D. R.; Graham, S.; Fan, Z.; Gomez-Casanovas, N.

    2012-12-01

    Climate change models vary widely in their predictions of the effects of climate forcing, in part because of difficulties in assigning sources of uncertainties and in simulating changes in the carbon source/sink status and climate-carbon cycle feedbacks of terrestrial ecosystems. We studied the impacts of vegetation and weather variations on carbon and energy fluxes at a restored tallgrass prairie in Illinois. The prairie was a strong carbon sink, despite a prolonged drought period and vegetation changes due to the presence of a non-native biennial plant. A model considering the combined effects of air temperature, precipitation, RH, incoming solar radiation, and vegetation was also developed and used to describe net ecosystem exchange for all years. The vegetation factor was represented in the model with summer albedo and/or NDVI. Results showed that the vegetation factor was more important than abiotic factors in describing changes in C and energy fluxes in ecosystems under disturbances. Changes from natives to a non-native forbs species had the strongest effect in reducing net ecosystem production and increasing sensible heat flux and albedo, which may result in positive feedbacks on warming. Here we show that non-native species invasions can alter the ecosystem sensitivity to climatic factors often construed in models.

  7. 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.

  8. Impacts of Salinity on Soil Hydraulic Properties and Evaporation Fluxes

    Science.gov (United States)

    Fierro, V.; Cristi Matte, F.; Suarez, F. I.; Munoz, J. F.

    2014-12-01

    Saline soils are common in arid zones, where evaporation from shallow groundwater is generally the main component of the water balance. Thus, to correctly manage water resources in these zones, it is important to quantify the evaporation fluxes. Evaporation from saline soils is a complex process that couples the movement of salts, heat, liquid water and water vapor, and strongly depends on the soil water content. Precipitation/dissolution reactions can change the soil structure and alter flow paths, modifying evaporation fluxes. We utilized the HYDRUS-1D model to investigate the effects of salinity on soil hydraulic properties and evaporation fluxes. HYDRUS-1D simulates the transport of liquid water, water vapor, and heat, and can incorporate precipitation/dissolution reactions of the major ions. To run the model, we determined the water retention curve for a soil with different salinities; and we used meteorological forcing from an experimental site from the Atacama Desert. It was found that higher sodium adsorption ratios in the soil increase the soil water retention capacity. Also, it was found that evaporation fluxes increase salts concentration near the soil surface, changing the soil's water retention capacity in that zone. Finally, movement of salts causes differences in evaporation fluxes. It is thus necessary to incorporate salt precipitation/dissolution reactions and its effects on the water retention curve to correctly simulate evaporation in saline soils

  9. 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.

  10. Methods for assessing environmental impacts of a FUSRAP property-cleanup/interim-storage remedial action

    International Nuclear Information System (INIS)

    This document provides a description of a property-cleanup/interim-storage action, explanation of how environmental impacts might occur, comprehensive treatment of most potential impacts that might occur as a result of this type of action, discussion of existing methodologies for estimating and assessing impacts, justification of the choice of specific methodologies for use in FUSRAP environmental reviews, assessments of representative impacts (or expected ranges of impacts where possible), suggested mitigation measures, and some key sources of information. The major topical areas covered are physical and biological impacts, radiological impacts, and socioeconomic impacts. Some project-related issues were beyond the scope of this document, including dollar costs, specific accident scenarios, project funding and changes in Congressional mandates, and project management (contracts, labor relations, quality assurance, liability, emergency preparedness, etc.). These issues will be covered in other documents supporting the decision-making process. Although the scope of this document covers property-cleanup and interim-storage actions, it is applicable to other similar remedial actions. For example, the analyses discussed herein for cleanup activities are applicable to any FUSRAP action that includes site cleanup

  11. Fracture toughness and mechanical properties of aluminum alloys for research reactors

    International Nuclear Information System (INIS)

    Aluminum alloys have been used as the structural material of the research reactor or because of their good properties for corrosion resistance and machinability as well as high neutron economy. In order to respond to the needs to maintain the aged core structure and to utilize for the high performance research reactor, irradiation test of aluminum alloys were initiated to provide the data base on the toughness and strength of aluminum alloys aged under research reactor condition. This report describes the results of tensile test, hardness test, Charpy impact test and fracture toughness test on A5052-O and A6061-T6 aluminum alloys under the unirradiated condition. From those tests, it was found that base metal of A5052-O has the highest toughness, welded joints of A5052-O and A6061-T6 is equivalent and have medium toughness, and base metal of A6061-T651 has very low toughness. (author)

  12. Polylactide/poly(hydroxybutyrate-co-hydroxyvalerate blends: Morphology and mechanical properties

    Directory of Open Access Journals (Sweden)

    S. Bronnikov

    2014-08-01

    Full Text Available The morphology and the mechanical properties of polylactide/poly(hydroxybutyrate-co-hydroxyvalerate blends of various compositions were studied. The statistical analysis of the scanning electron microscopy images allowed finding two statistical ensembles of the minor-phase particles. The first ensemble involves the dispersed particles, whereas the second one contains the coalesced particles. The mean diameters of both dispersed and coalesced minor-phase particles were calculated and plotted against the blend composition. Young’s modulus, tensile strength, elongation at break, and Charpy impact strength of the blends were determined and examined as a function of the blend composition. The Young’s modulus values were shown to be in accordance with theoretical predictions.

  13. The effect of reduced oxygen content powder on the impact toughness of 316 steel powder joined to 316 steel by low temperature HIP

    International Nuclear Information System (INIS)

    During the manufacture of the blanket modules, 316L steel powder is simultaneously consolidated and joined to tubes and blocks of 316L materials by Hot Isostatic Pressing (HIP). The high processing temperature can detrimentally increase the grain size of the water cooling tubes in the structure and the blocks reducing their strength. It is well known that surface oxides on the powder particles negatively influence the impact toughness of material and joints consolidated in this way. By increasing the consolidation temperature the metallurgical bonding is improved, due to a redistribution of oxygen within the oxide layer towards more discrete oxide particles. In order to get acceptable mechanical properties of materials produced at a low HIP temperature the oxygen content on the powder surfaces needs to be reduced. The aim of this new techniques to reduce the oxygen content of the metal powder. The influence on Charpy impact energy and tensile strength were demonstrated

  14. 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.

  15. Impact of leg lengthening on viscoelastic properties of the deep fascia

    OpenAIRE

    Wu Zi-Xiang; Wei Yi-Yong; Wang Hai-Qiang; Luo Zhuo-Jing

    2009-01-01

    Abstract Background Despite the morphological alterations of the deep fascia subjected to leg lengthening have been investigated in cellular and extracellular aspects, the impact of leg lengthening on viscoelastic properties of the deep fascia remains largely unknown. This study aimed to address the changes of viscoelastic properties of the deep fascia during leg lengthening using uniaxial tensile test. Methods Animal model of leg lengthening was established in New Zealand white rabbits. Dist...

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

    OpenAIRE

    Tiago Jose Antoszczyszyn; Rodrigo Metz Gabriel Paes; Ana Sofia Clímaco Monteiro de Oliveira; Adriano Scheid

    2014-01-01

    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 (PT...

  17. Irrigation suitability of North Bengal Sugar Mill’s effluent and its impact on soil properties

    OpenAIRE

    Tabriz, S.S.; Mojid, M. A.; Wyseure, G.C.L

    2011-01-01

    The suitability of effluent water (hereafter called wastewater) from North Bengal Sugar Mill (NBSM) for irrigation and its impact on soil properties were evaluated. The quality parameters of wastewater from three different locations of the drainage canal and one freshwater sample from a hand tubewell of the NBSM complex were determined. The major physico-chemical and hydraulic properties of the wastewater affected and unaffected soils from West Baiddanathpur village (hereafter referred to as ...

  18. A compilation of structural property data for computer impact calculation (5/5)

    International Nuclear Information System (INIS)

    The paper describes structural property data for computer impact calculations of nuclear fuel shipping casks. Four kinds of material data, mild steel, stainless steel, lead and wood are compiled. These materials are main structural elements of shipping casks. Structural data such as, the coefficient of thermal expansion, the modulus of longitudinal elasticity, the modulus of transverse elasticity, the Poisson's ratio and stress and strain relationships, have been tabulated against temperature or strain rate. This volume 5 involve structural property data of wood. (author)

  19. A compilation of structural property data for computer impact calculation (4/5)

    International Nuclear Information System (INIS)

    The paper describes structural property data for computer impact calculations of nuclear fuel shipping casks. Four kinds of material data, mild steel, stainless steel, lead and wood are compiled. These materials are main structural elements of shipping casks. Structural data such as, the coefficient of thermal expansion, the modulus of longitudinal elasticity, the modulus of transverse elasticity, the Poisson's ratio and stress and strain relationships, have been tabulated against temperature or strain rate. This volume 4 involve structural property data of lead. (author)

  20. 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.

  1. 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.

  2. 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.

    2016-04-01

    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.

  3. Effect of multiple impacts on protective properties of external hip protectors

    Directory of Open Access Journals (Sweden)

    Tatjana Bulat

    2008-10-01

    Full Text Available Tatjana Bulat1, Shawn Applegarth1, Stuart Wilkinson2, Shirley G Fitzgerald1, Shahbaz Ahmed1, Patricia Quigley11VISN 8 Patient Safety Center of Inquiry, Tampa, FL, USA; 2University of South Florida Department of Mechanical Engineering, Tampa, FL, USAAbstract: A variety of external hip protectors are available on the market but no standards for their performance exist and it is unknown if their properties change after repeated fall impacts. The purpose of this study was to determine if protective properties change in different types of new (unused hip protectors after repeated, simulated falls. Five hip protector brands were chosen to represent different products available on the market and the two mechanisms employed in reducing the force of an impact (shunting or absorbing. Ten pairs of each type (20 pads for each brand were tested using a 1.8-m Instron Dynatup 9250 HV vertical impact testing tower. The impact testing system was specifically designed for this study by creating a simulated trochanter to provide more accurately a impact area similar to that of a real hip bone. The hip protectors were impacted once a day for 3 consecutive days. Repeated impacts demonstrated the pads’ decreased ability to either absorb or shunt force in all types of hip protectors. However, the mean forces were still in the protective range (force below fracture threshold of 3100 N for 3 of the 5 brands tested after 3 impacts. The protective properties of external hip protectors do degrade after repeated impacts. The degree of degradation differs from brand to brand. Regardless of type, most pads were still able to bring the force of impact below the fracture threshold of 3100 N. Future studies need to address the issue of durability of different types/brands of hip protectors after repeated laundering and fall impacts to determine when should they be replaced. Additionally, a national or international standard needs to be developed against which the performance

  4. Dynamic finite element method modeling of the upper shelf energy of precracked Charpy specimens of neutron irradiated weld metal 72W

    International Nuclear Information System (INIS)

    Dynamic finite element modeling of the fracture behavior of fatigue-precracked Charpy specimens in both unirradiated and irradiated conditions was performed using a computer code, ABAQUS Explicit, to predict the upper shelf energy of precracked specimens of a given size from experimental data obtained for a different size. A tensile fracture-strain based method for modeling crack extension and propagation was used. It was found that the predicted upper shelf energies of full and half size precracked specimens based on third size data were in reasonable agreement with their respective experimental values. Similar success was achieved for predicting the upper shelf energy of subsize precracked specimens based on full size data

  5. 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.

  6. 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.

  7. Determining perception-based impacts of noxious facilities on wage rates and property values

    Energy Technology Data Exchange (ETDEWEB)

    Nieves, L.A.; Clark, D.E.

    1992-02-01

    This document, written for the US Department of Energy, discusses current information and the need for future research on estimating the impacts on wages and property values that could result from people`s perceptions of the risks associated with noxious facilities. Psychometric studies indicate that the US population is averse to living near noxious facilities, nuclear-related facilities in particular. Contingent valuation and hedonic studies find that the net economic impacts of proximity to noxious facilities are generally negative and often substantial. Most of these studies are limited in scope, and none estimate the impacts derived from public perceptions of such facilities. This study examines the mechanisms by which negative public perceptions result in economic impacts reflected in wages and property values. On the basis of these mechanisms, it develops a predictive model of perception-based impacts and identifies the data and methods needed to implement it. The key to predicting perception-based impacts lies in combining psychometric and hedonic methods. The reliability of psychometric measures as indicators of aversive stimuli that precipitate economic impacts can be empirically tested. To test the robustness of the findings, alternative estimation methods an be employed in the hedonic analysis. Contingent valuation methods can confirm the results.

  8. Determining perception-based impacts of noxious facilities on wage rates and property values

    Energy Technology Data Exchange (ETDEWEB)

    Nieves, L.A.; Clark, D.E.

    1992-02-01

    This document, written for the US Department of Energy, discusses current information and the need for future research on estimating the impacts on wages and property values that could result from people's perceptions of the risks associated with noxious facilities. Psychometric studies indicate that the US population is averse to living near noxious facilities, nuclear-related facilities in particular. Contingent valuation and hedonic studies find that the net economic impacts of proximity to noxious facilities are generally negative and often substantial. Most of these studies are limited in scope, and none estimate the impacts derived from public perceptions of such facilities. This study examines the mechanisms by which negative public perceptions result in economic impacts reflected in wages and property values. On the basis of these mechanisms, it develops a predictive model of perception-based impacts and identifies the data and methods needed to implement it. The key to predicting perception-based impacts lies in combining psychometric and hedonic methods. The reliability of psychometric measures as indicators of aversive stimuli that precipitate economic impacts can be empirically tested. To test the robustness of the findings, alternative estimation methods an be employed in the hedonic analysis. Contingent valuation methods can confirm the results.

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

    International Nuclear Information System (INIS)

    A multilayer aluminium laminate comprising 10 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, which was 18 times higher than that for the as-received Al-Zn-Mg-Cu alloy. The improvement in damage tolerance was due to the high volume fraction of the high-strength aluminium and extrinsic fracture mechanisms.

  10. A Demographic Analysis of the Impact of Property Tax Caps on Indiana School Districts

    Science.gov (United States)

    Hirth, Marilyn A.; Lagoni, Christopher

    2014-01-01

    In 2008, the Indiana legislature passed and the governor signed into law House Enrolled Act No. 1001, now referred to as Public Law 146-2008, which capped Indiana school districts' ability to raise revenues from the local property tax without local voter approval. To phase in the impact of the law, the state provided school districts with…

  11. Silica Bridge Impact on Hollow-core Bragg Fiber Transmission Properties

    DEFF Research Database (Denmark)

    Poli, F.; Foroni, M.; Giovanelli, D.;

    2007-01-01

    The silica bridges impact on the hollow-core Bragg fiber guiding properties is investigated. Results demonstrate that silica nanosupports are responsible for the surface mode presence, which causes the peaks experimentally measured in the transmission spectrum. © 2006 Optical Society of America....

  12. Theoretical Prediction of Dynamic Composite Material Properties for Hypervelocity Impact Simulations

    OpenAIRE

    Ryan, S; Wicklein, M.; Mouritz, A.; Riedel , W.; Schäfer, F.; Thoma, K

    2009-01-01

    Abstract Recent advances in the description of fibre-reinforced polymer composite material behaviour under extreme loading rates provide a significant extension in capabilities for numerical simulation of hypervelocity impact on composite satellite structures. Given the complexity of the material model, extensive material characterisation is required, however, as the properties of composite materials are commonly tailored for a specific application, experimental characterisation is...

  13. Tensile and impact properties of the steel MANET-II and their optimization

    International Nuclear Information System (INIS)

    The report describes the investigations concerning tensile and impact bending properties done in the IMF-II of the KfK. The tensile tests include the investigation of the parameters test temperature, deformation rate, specimen site, cast, dimensions of the semi finished products and other parameters. The material has an adequate strength (e.g. Rp0,2 (500 C) = 465 MPa), a sufficient ductility (e.g. A > 10%) and a good homogenity of this properties. The impact bending properties of some heats of the MANET-II grade steel had been investigated using instrumented V-notch impact bending tests, and it has been compared with other steels. The strength of the MANET-II grade steel, measured by the maximum load and the stress intensity factor, is very high. The ductility, measured by the specimen bending up to the cleavage fracture, is sufficient. The toughness of the material, measured by the upper shelf energy of the impact strength, by the energy up to the maximum load and by the J-integral, is adequate. Only the transition temperature of the impact energy (DBTT = 0 C) and the FATT (T = +4 C) are too high. The limiting temperature of the first or last appearance of cleavage fracture is too high, too. For that reason an optimization of the thermal treatment of the steel had been attempted. That leads to a higher yield strength at elevated temperature and to a lower DBTT = -30 C. (orig.)

  14. The evaluation of irradiation effect on the mechanical properties of the oxide dispersion strengthened ferritic steel claddings. Irradiated at JOYO/CMIR-4 and 5

    International Nuclear Information System (INIS)

    The effect of fast neutron irradiation on the mechanical properties of the oxide dispersion strengthened (ODS) ferritic steel claddings (1DS and 1DK) which were manufactured by warm working as the first trial cladding tube manufacturing in JNC, were investigated. The samples were irradiated in JOYO/CMIR-4 and 5. Uni-axial tensile test, ring-tensile test, burst test and miniaturized Charpy impact test were carried out to study the mechanical properties such as strength and elongation, of irradiated ODS ferritic claddings. The results of this study showed that there was no considerable deterioration on the mechanical properties of these ODS ferritic steel cladding samples under the irradiation conditions examined. The results obtained in this study are as follows; 1) The increase in strength due to irradiation hardening appeared in higher temperatures (∼600, 650degC) than that of austenitic steels such as PNC316. 2) There was an anisotropy in the short time range strengths after irradiation due to its particular crystalline structure so called ''bamboo structure''. 3) The elongation of hoop direction after irradiation was significantly tended to be much lower than that of longitudinal direction because of its particular ''bamboo structure''. 4) There was no obvious decrease in elongation and miniaturized Charpy impact properties under irradiation conditions examined. 5) TEM observation showed that there was no significant change in microstructure before and after irradiation except the precipitation of Laves phase on grain boundary after irradiation and that Y2O3 particles and their fine distribution might be stable during irradiation. (author)

  15. A Novel Ni-Containing Powder Metallurgy Steel with Ultrahigh Impact, Fatigue, and Tensile Properties

    Science.gov (United States)

    Wu, Ming-Wei; Shu, Guo-Jiun; Chang, Shih-Ying; Lin, Bing-Hao

    2014-08-01

    The impact toughness of powder metallurgy (PM) steel is typically inferior, and it is further impaired when the microstructure is strengthened. To formulate a versatile PM steel with superior impact, fatigue, and tensile properties, the influences of various microstructures, including ferrite, pearlite, bainite, and Ni-rich areas, were identified. The correlations between impact toughness with other mechanical properties were also studied. The results demonstrated that ferrite provides more resistance to impact loading than Ni-rich martensite, followed by bainite and pearlite. However, Ni-rich martensite presents the highest transverse rupture strength (TRS), fatigue strength, tensile strength, and hardness, followed by bainite, pearlite, and ferrite. With 74 pct Ni-rich martensite and 14 pct bainite, Fe-3Cr-0.5Mo-4Ni-0.5C steel achieves the optimal combination of impact energy (39 J), TRS (2170 MPa), bending fatigue strength at 2 × 106 cycles (770 MPa), tensile strength (1323 MPa), and apparent hardness (38 HRC). The impact energy of Fe-3Cr-0.5Mo-4Ni-0.5C steel is twice as high as those of the ordinary high-strength PM steels. These findings demonstrate that a high-strength PM steel with high-toughness can be produced by optimized alloy design and microstructure.

  16. Global Geometric Properties of Martian Impact Craters: A Preliminary Assessment Using Mars Orbiter Laser Altimeter (MOLA)

    Science.gov (United States)

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

    1999-01-01

    Impact craters on Mars have been used to provide fundamental insights into the properties of the martian crust, the role of volatiles, the relative age of the surface, and on the physics of impact cratering in the Solar System. Before the three-dimensional information provided by the Mars Orbiter Laser Altimeter (MOLA) instrument which is currently operating in Mars orbit aboard the Mars Global Surveyor (MGS), impact features were characterized morphologically using orbital images from Mariner 9 and Viking. Fresh-appearing craters were identified and measurements of their geometric properties were derived from various image-based methods. MOLA measurements can now provide a global sample of topographic cross-sections of martian impact features as small as approx. 2 km in diameter, to basin-scale features. We have previously examined MOLA cross-sections of Northern Hemisphere and North Polar Region impact features, but were unable to consider the global characteristics of these ubiquitous landforms. Here we present our preliminary assessment of the geometric properties of a globally-distributed sample of martian impact craters, most of which were sampled during the initial stages of the MGS mapping mission (i.e., the first 600 orbits). Our aim is to develop a framework for reconsidering theories concerning impact cratering in the martian environment. This first global analysis is focused upon topographically-fresh impact craters, defined here on the basis of MOLA topographic profiles that cross the central cavities of craters that can be observed in Viking-based MDIM global image mosaics. We have considered crater depths, rim heights, ejecta topologies, cross-sectional "shapes", and simple physical models for ejecta emplacement. To date (May, 1999), we have measured the geometric properties of over 1300 impact craters in the 2 to 350 km diameter size interval. A large fraction of these measured craters were sampled with cavity-center cross-sections during the first

  17. 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.

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

    International Nuclear Information System (INIS)

    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−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−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-Ni3Nb was observed after thermal exposure. However, a complete transformation from metastable γ″ to δ-Ni3Nb 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

  19. 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.

  20. The inclined impact test, an efficient method to characterize coatings' cohesion and adhesion properties

    International Nuclear Information System (INIS)

    The impact test, supported by its finite elements method (FEM) simulation, has been successfully used to characterize the fatigue performance of coatings. In this test, the load is exercised perpendicularly to the coated surface by a cemented carbides ball. In the inclined impact test, the successive impacts are applied on an inclined surface. In this way, the coated surfaces are loaded vertically and tangentially simultaneously. The coating fatigue failure modes were classified by means of scanning electron microscopy (SEM) observations and energy dispersive X-ray spectroscopy microanalyses. The experimental method is supported by a developed FEM simulation, which considers the mechanical elastic-plastic properties of the coating and of the substrate, as well as of the ball indenter during the impact test, thus enabling the elucidation of the coating failure modes. In this way, critical equivalent stresses were determined and the coating cohesive and adhesive impact performance was systematically investigated. The inclined impact test implies a new reference to the prediction of the coatings' cohesive and adhesive failure, managing to approach loading directions for a variety of coated surfaces in different applications. Examples for an efficient use of this test are presented and a characteristic magnitude, the coating impact adhesion (CIA), is introduced

  1. Impact of microstructural evolutions during thermal aging of Alloy 625 on its monotonic mechanical properties

    Directory of Open Access Journals (Sweden)

    Suave Lorena Mataveli

    2014-01-01

    Full Text Available Alloy 625 is widely used for petrochemical, marine and aerospace applications owing to its outstanding corrosion and mechanical properties at high temperatures. However, this alloy is prone to complex microstructure evolutions above 500 ∘C that may impact its mechanical properties. In this study, the impact of its microstructure evolutions occurring upon thermal aging on the monotonic mechanical properties has been studied. Thermal exposures of up to ∼2000 hours in the 550 ∘C – 900 ∘C temperature range have been investigated. TTT diagrams of the δ and γ′′ phases were established based on high resolution scanning electron microscopy observations. The evolutions of secondary carbides distributions were also followed. It has been observed a steep increase of the room temperature micro-hardness after overagings performed at 650 ∘C and 700 ∘C due to the precipitation of the γ′′ phase. Moreover, it is clearly demonstrated a strengthening effect of the δ phase observed after long term thermal exposures at temperatures in excess of 700 ∘C. Finally, the impact of a thermal aging in the γ′′ precipitation domain on the tensile properties was evaluated from room temperature up to 800 ∘C. It is shown that the loss of high temperature ductility is not correlated to the precipitation of grain boundary secondary carbides.

  2. The use of single-specimen techniques for measuring upper shelf toughness properties under impact loading rates. Convention TRACTEBEL/SCK-CEN 2005 Task 1.1.5

    International Nuclear Information System (INIS)

    The multiple-specimen method (low-blow or stop-block tests) is the conventional approach for measuring the upper shelf fracture toughness of metallic materials under impact loading rates, typically fatigue precracked Charpy specimens tested on an instrumented pendulum machine. The method is fairly simple but requires a relatively large number of specimens. Nowadays, several single-specimen methods are available, which are purely based on the analysis of the instrumented force/displacement trace; they don't need any dedicated instrumentation for the measurement of crack extension during the test. Three of these techniques have been applied in this work to low-blow tests performed at different temperatures on two significantly different RPV steels (20MnMoNi55 and JSPS): the Normalization Data Reduction (NDR) technique, Schindler's Analytical 3-Parameter Approach and Chaouadi's method. Analyses have been performed after applying a double fitting approach to the raw test data, which allows selecting a limited set of force/displacement data which are representative of the whole instrumented trace. Results show that all three methods provide acceptable accuracy in terms of both ductile crack initiation and resistance to crack propagation (tearing modulus). However, for this type of analysis we recommend the use of the more widely accepted NDR technique, which is described in detail in the ASTM E1820-01 standard (although the limitations on data smoothness presently enforced in the standard seem incompatible with the oscillations of a typical dynamic PCCv curve). (author)

  3. 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.

  4. Mechanical Properties of Granular Materials and Their Impact on Load Distribution in Silo: A Review

    Directory of Open Access Journals (Sweden)

    Horabik J.

    2015-01-01

    Full Text Available Mechanical properties of granular materials and their impact on load distribution in storage silo were discussed with special focus on materials of biological origin. Granular materials classification was briefly outlined. The evolution of constitutive models of granular materials developed in the frame of mechanics of continuum was addressed. Analytical methods, Finite Element Methods (FEM, and Discrete Element Methods (DEM of estimation of silo pressure were discussed. Special attention was paid to the following issues: dynamic pressure switch in the first moment of silo discharge, asymmetry of loads due to eccentric discharge, and impact of uncontrolled increase of moisture content of grain on silo pressures.

  5. 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.

  6. Characterization of Physical, Thermal and Structural Properties of Chromium (VI) Oxide Powder: Impact of Biofield Treatment

    OpenAIRE

    Trivedi, Mahendra; Branton, Alice; Trivedi, Dahryn; Nayak, Gopal

    2015-01-01

    Chromium (VI) oxide (CrO3) has gained extensive attention due to its versatile physical and chemical properties. The objective of the present study was to evaluate the impact of biofield treatment on physical, thermal and structural properties of CrO3 powder. In this study, CrO3 powder was divided into two parts i.e. control and treatment. Control part was remained as untreated and treated part received Mr. Trivedi’s biofield treatment. Subsequently, control and treated CrO3 samples were char...

  7. A compilation of structural property data for computer impact calculation (3/5)

    International Nuclear Information System (INIS)

    The paper describes structural property data for computer impact calculations of nuclear fuel shipping casks. Four kinds of material data, mild steel, stainless steel, lead and wood are compiled. These materials are main structural elements of shipping casks. Structural data such as, the coefficient of thermal expansion, the modulus of longitudinal elasticity, the modulus of transverse elasticity, the Poisson's ratio and stress and strain relationships, have been tabulated against temperature or strain rate. This volume 3 involve structural property data of stainless steel. (author)

  8. Instrumented impact testing machine with reduced specimen oscillation effects

    International Nuclear Information System (INIS)

    Owing to small and inexpensive specimens the Charpy impact test is widely used in quality control and alloy development. Limitations in power reactor survellance capsules it is also widely used for safety analysis purposes. Instrumenting the tup and computerizing data acquisition, makes dynamic fracture mechanics data measurement possible and convenient. However, the dynamic effects (inertia forces, specimen oscillations) in the impact test cause inaccuracies in the recorded load-time diagram and hence diminish the reliability of the calculated dynamic fracture mechanics parameters. To decrease inaccuracies a new pendulum type of instrumented impact test apparatus has been developed and constructed in the Metals Laboratory of the Technical Research Centre of Finland. This tester is based on a new principle involving inverted test geometry. The purpose of the geometry inversion is to reduce inertia load and specimen oscillation effects. Further, the new impact tester has some other novel features: e.g. the available initia impact energy is about double compared to the conventional standard (300 J) impact tester allowing the use of larger (10 x 20 x 110 mm) bend specimens than normal Charpy specimens. Also, the rotation asix in the three point bending is nearly stationary making COD-measurements possible. An experimental test series is described in which the inertia effects and specimen oscillations are compared in the conventional and new impact tester utilizing Charpy V-notch specimens. Comparison of the two test geometries is also made with the aid of an analytical model using finite element method (FEM) analysis. (author)

  9. Impacts of Hematite Nanoparticle Exposure on Biomechanical, Adhesive, and Surface Electrical Properties of Escherichia coli Cells

    OpenAIRE

    Zhang, Wen; Hughes, Joseph; Chen, Yongsheng

    2012-01-01

    Despite a wealth of studies examining the toxicity of engineered nanomaterials, current knowledge on their cytotoxic mechanisms (particularly from a physical perspective) remains limited. In this work, we imaged and quantitatively characterized the biomechanical (hardness and elasticity), adhesive, and surface electrical properties of Escherichia coli cells with and without exposure to hematite nanoparticles (NPs) in an effort to advance our understanding of the cytotoxic impacts of nanomater...

  10. The impact of cold deformation, annealing temperatures and chemical assays on the mechanical properties of platinum

    OpenAIRE

    Trumić B.; Stanković D.; Ivanović A.

    2010-01-01

    In order to form the necessary data base on platinum and platinum metals, certain tests were carried out on platinum samples of different purity of 99.5%, 99.9% and 99.99%. The degree of cold deformation, annealing temperature and chemical assays were tested as well as their impact on the mechanical properties of platinum. The Vickers hardness (HV) values were determined with different deformation degree, starting from annealing temperatures for platinum of different purity and tensile streng...

  11. Mechanical Properties of Granular Materials and Their Impact on Load Distribution in Silo: A Review

    OpenAIRE

    Horabik J.; Molenda M.

    2015-01-01

    Mechanical properties of granular materials and their impact on load distribution in storage silo were discussed with special focus on materials of biological origin. Granular materials classification was briefly outlined. The evolution of constitutive models of granular materials developed in the frame of mechanics of continuum was addressed. Analytical methods, Finite Element Methods (FEM), and Discrete Element Methods (DEM) of estimation of silo pressure were discussed. Special attention w...

  12. The Impact of Political Transformation on the South African Commercial Property Market

    OpenAIRE

    F. Viruly; Pienaar, E

    2007-01-01

    This study considers the impact that the transformation of the South African socio-political environment has had on locational decision making in the South African commercial property market. A central theme of the apartheid policy was to underpin and promote the economic viability of homelands and specific areas in metropolitan areas through a national decentralization policy and more specifically the provision of financial locational incentives. In addition, townships in close proximity to ...

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

    OpenAIRE

    2011-01-01

    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...

  14. Impact of wheeled and tracked tractors on soil physical properties in a mixed conifer stand

    OpenAIRE

    Cambi M.; Certini G; Fabiano F; Foderi C; Laschi A; Picchio R

    2015-01-01

    Damage to forest soil caused by vehicle traffic mainly consists of soil compaction, displacement, and rut formation. Severity of the damage depends on vehicle mass, weight of the carried loads, ground morphology, and soil properties, such as moisture. This paper investigates the impacts of two types of vehicles (tracked or wheeled tractor), traffic intensities (one or five skidding cycles) and soil moisture (24% or 13% by weight) on compaction of a loam textured soil in a mixed conifer stand ...

  15. Land Use and Property Market Impacts of the Relocation of Athens International Airport

    OpenAIRE

    Politakis, Alexis

    2006-01-01

    This dissertation investigates the impact of the relocation of Athens International Airport (AIA), the most significant urban development in the modern history of the city of Athens, on land uses and the property market around the former airport site (FAS) and the new Eleftherios Venizelos airport (EV). Airport relocations are in themselves relatively rare events in global aviation. In this dissertation, for the first time, sources from various fields are brought together to be...

  16. 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

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

    Science.gov (United States)

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

    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.

  18. 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.

  19. The impacts of nuclear facilities on property values and other factors in the surrounding communities

    International Nuclear Information System (INIS)

    This paper addresses the issue of the impact of the siting of nuclear facilities on the adjacent communities. It reviews previous studies on the issue and then empirically examines the impacts of seven major nuclear facilities located throughout the USA on the surrounding communities. The analysis focuses on the effects on local property values, economic growth, tax revenues, public services, community development, jobs and employment, and schools. Using published data, economic and statistical analyses, literature reviews and interviews, it finds that the impacts of these facilities have been largely positive. The findings are placed in perspective, caveats are noted concerning the generalisation of the conclusions derived and recommendations for required further research are provided. (author)

  20. 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.

  1. 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

  2. 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.

  3. Evaluation of material properties considering thermal embrittlement for accelerated aged CF-8M and CF-8A cast austenitic stainless steel

    International Nuclear Information System (INIS)

    Cast austenitic stainless steel have been widely used for primary coolant piping in light water reactors. This material is subject to thermal embrittlement at reactor operating temperature. CF-8M and CF-8A cast austenitic stainless steel is used for several components, such as primary coolant piping, elbow, pump casing, and valve bodies in light water reactors. Thermal embrittlement results in spinodal decomposition of delta-ferrite leading to decreased fracture toughness. In this study, the specimens were prepared using an accelerated aging method. The measurement of ferrite content, Charpy impact test and J-R test were performed to verify the predicting equation for aged material properties. In case of above 25% ferrite content, predicted result of J-R curve might be non-conservative

  4. Microstructures and Mechanical Properties of Laser Welding Joint of a CLAM Steel with Revised Chemical Compositions

    Science.gov (United States)

    Chen, Shuhai; Huang, Jihua; Lu, Qi; Zhao, Xingke

    2016-05-01

    To suppress the tendency to form delta ferrite in weld metal (WM) of China low activation martensitic (CLAM) steel joint, a CLAM steel with revised chemical compositions was designed. Laser welding of the CLAM steel was investigated. The microstructures of the WM and heat-affected zone were analyzed. The impact toughness of the WM was evaluated by a Charpy impact test method with three V notches. The influence of temper temperature on mechanical properties was analyzed. It was found that the delta ferrite was eliminated almost completely in laser WM of CLAM steel with revised chemical compositions which has lower tendency to form delta ferrite than original chemical compositions. The joint has higher tensile strength than the parent metal. With increasing the heat input, the impact toughness of the joint is approximatively equal with that of parent metal first and then decreases obviously. Temper treatment could effectively improve mechanical property of the joint. When the temper temperature exceeds 600 °C, the impact toughness of the joint is higher than that of the parent metal.

  5. Microstructures and Mechanical Properties of Laser Welding Joint of a CLAM Steel with Revised Chemical Compositions

    Science.gov (United States)

    Chen, Shuhai; Huang, Jihua; Lu, Qi; Zhao, Xingke

    2016-03-01

    To suppress the tendency to form delta ferrite in weld metal (WM) of China low activation martensitic (CLAM) steel joint, a CLAM steel with revised chemical compositions was designed. Laser welding of the CLAM steel was investigated. The microstructures of the WM and heat-affected zone were analyzed. The impact toughness of the WM was evaluated by a Charpy impact test method with three V notches. The influence of temper temperature on mechanical properties was analyzed. It was found that the delta ferrite was eliminated almost completely in laser WM of CLAM steel with revised chemical compositions which has lower tendency to form delta ferrite than original chemical compositions. The joint has higher tensile strength than the parent metal. With increasing the heat input, the impact toughness of the joint is approximatively equal with that of parent metal first and then decreases obviously. Temper treatment could effectively improve mechanical property of the joint. When the temper temperature exceeds 600 °C, the impact toughness of the joint is higher than that of the parent metal.

  6. Low temperature mechanical properties, fractographic and metallographic evaluation of several alloy steels

    Science.gov (United States)

    Montano, J. W.

    1973-01-01

    The mechanical properties are presented of alloy steels, 4130, 4140, 4340, 6150, and 8740. Test specimens were manufactured from approximately 1.00 inch (2.54 cm) diameter bar stock which had been heat treated to two different hardness levels. The following mechanical tests were performed at temperatures of 80 F (+26.7 C), 0 F (-17.8 C), -100 F (-73 C), and -200 F (-129 C): (1) tensile test (Ultimate, yield, modulus, elongation, and reduction of area), (2) notched tensile test, (3) charpy V-notched impact test (impact energy), and (4) double shear strength test (ultimate and yield). The test data indicate excellent tensile strength, notched/unnotched tensile ratios, ductility, impact, and shear properties at all test temperatures, except at -200 F (-129 C) where the impact strength of the higher strength group of alloy steels, 4130 (Rc-37) and 4140 (Rc-44) decreased to approximately 9 ft. lbs. (12 joules) and 6 ft. lbs. (8 joules), respectively. Chemical, metallographic, and fractographic analyses were also performed to evaluate microstructure, microhardness and the effect of decrease in temperature on the ductile to brittle failure transition.

  7. Influence of increasing notch radius on properties of nitrided hot work tool steels

    Energy Technology Data Exchange (ETDEWEB)

    Rosso, M.; Scavino, G.; Ugues, D. [Politecnico di Torino - Dipt. di Scienza dei Materiali e Ingegeneria Chimica (Italy); Bennani, A. [COGNE Acciai Speciali - Aosta (Italy)

    2000-07-01

    Tool steels are a very large group of complex alloys which have evolved for many diverse hot and cold forming applications and they constitute a class of strategic materials. Hot work tool steels fall into groups which have either chromium, tungsten, or molibdenum as the major alloying element. The medium carbon and the relatively high alloy content make these steels air hardenable and resistant to impact and softening during repeated exposure to hot working operations. In this work the impact properties of Charpy U-notch samples with increasing notch radius are presented and discussed. The samples were manufactured with AISI H13 hot working tool steel and a modified composition, and were tested in the as quenched state and after nitriding. After the impact test, the microhardness properties were evaluated and correlated to the heat treatment. The notch radius strongly affect the impact resistance of the samples, namely at the lowest values. The microstructure details and the fracture morphology were observed by light microscopy and SEM. (orig.)

  8. The impact of oil and natural gas facilities on rural residential property values

    Energy Technology Data Exchange (ETDEWEB)

    Boxall, P.C. [Alberta Univ., Edmonton, AB (Canada). Dept. of Rural Economy

    2005-07-01

    This PowerPoint presentation examined challenges in the economic valuation of environmental changes within the context of formal real estate markets. It was proposed that some values that are expressed in markets can be affected by environmental changes and should be used in resource development land assessments. Details of indirect market valuation and revealed preference methods were reviewed. An outline of hedonic pricing was presented. It was noted that hedonic pricing can be used with other market values and prices such as tourism, art prices and hotel prices, where multivariate regression techniques are used and regression coefficients reveal information on the implicit prices of certain characteristics. Property value examples in the environmental economics literature were reviewed. A case study using data from eco-terrorism costs was presented. Issues concerning sour gas facilities were discussed with reference to public anxiety over hydrogen sulfide (H{sub 2}S) toxicity and flares. Concerns over health risks and negative amenity impacts were discussed. The impacts of sour gas facilities on property values of residential acreages in and around Calgary were considered, and a map of the study area was presented. An outline of emergency plan response zones was provided. Price effects of industry facilities were presented, including marginal and cumulative impacts on price. It was concluded that oil and gas activities have significant impacts on rural residential property prices, but that industry members currently report that there is little to no effect. It was suggested that the research presented in this paper could be used to assess levels of compensation. tabs., figs.

  9. The impact of oil and natural gas facilities on rural residential property values

    International Nuclear Information System (INIS)

    This PowerPoint presentation examined challenges in the economic valuation of environmental changes within the context of formal real estate markets. It was proposed that some values that are expressed in markets can be affected by environmental changes and should be used in resource development land assessments. Details of indirect market valuation and revealed preference methods were reviewed. An outline of hedonic pricing was presented. It was noted that hedonic pricing can be used with other market values and prices such as tourism, art prices and hotel prices, where multivariate regression techniques are used and regression coefficients reveal information on the implicit prices of certain characteristics. Property value examples in the environmental economics literature were reviewed. A case study using data from eco-terrorism costs was presented. Issues concerning sour gas facilities were discussed with reference to public anxiety over hydrogen sulfide (H2S) toxicity and flares. Concerns over health risks and negative amenity impacts were discussed. The impacts of sour gas facilities on property values of residential acreages in and around Calgary were considered, and a map of the study area was presented. An outline of emergency plan response zones was provided. Price effects of industry facilities were presented, including marginal and cumulative impacts on price. It was concluded that oil and gas activities have significant impacts on rural residential property prices, but that industry members currently report that there is little to no effect. It was suggested that the research presented in this paper could be used to assess levels of compensation. tabs., figs

  10. A study on the intercritical annealing treatment on the mechanical properties of SA106 Gr.C piping steel

    International Nuclear Information System (INIS)

    From the point of view on material properties in Leak-Before-Break (LBB) analysis, the premise of LBB is that the materials used are sufficiently tough (ductile) that small through-wall crack would remain stable. It is reported, however, that the toughness and LBB safety margins of SA106 Gr.C piping steel is reduced due to dynamic strain aging (DSA) at the reactor operating temperature. In this study, intercritical annealing in two-phase (α+γ) region was performed to investigate the possibility of improving the toughness and reducing DSA susceptibility for giving allowable LBB safety margins. Tensile tests were carried out under various temperatures and strain rates for assessing the material properties with the heat treatments. Also, Charpy impact tests were conducted to measure impact toughness at room temperature. After intercritical annealing, the manifestations of DSA were observed in the tensile properties. However, the ductility loss caused by DSA was smaller than the as-received material. Furthermore, the intercritical annealing was able to increase the impact toughness by 1.5 times compared to as-received material. With the heat treatment, we could obtain some kinds of microstructural changes such as the cleaner retained ferrite, increased ferrite content and somewhat finer grain size. It is considered that the reduced DSA sensitivity was induced by cleaner retained ferrite and it resulted in higher impact toughness in addition to the general toughening due to finer grain sizes and increased ferrite content

  11. Modulation of pyridinium cationic lipid-DNA complex properties by pyridinium gemini surfactants and its impact on lipoplex transfection properties.

    Science.gov (United States)

    Sharma, Vishnu Dutt; Lees, Julia; Hoffman, Nicholas E; Brailoiu, Eugen; Madesh, Muniswamy; Wunder, Stephanie L; Ilies, Marc A

    2014-02-01

    The study presents the effects of blending a cationic gemini surfactant into cationic lipid bilayers and its impact on the plasmid DNA compaction and delivery process. Using nanoDSC, dynamic light scattering, zeta potential, and electrophoretic mobility measurements, together with transfection (2D- and 3D-) and viability assays, we identified the main physicochemical parameters of the lipid bilayers, liposomes, and lipoplexes that are affected by the gemini surfactant addition. We also correlated the cationic bilayer composition with the dynamics of the DNA compaction process and with transfection efficiency, cytotoxicity, and the internalization mechanism of the resultant nucleic acid complexes. We found that the blending of gemini surfactant into the cationic bilayers fluidized the supramolecular assemblies, reduced the amount of positive charge required to fully compact the plasmid DNA and, in certain cases, changed the internalization mechanism of the lipoplexes. The transfection efficiency of select ternary lipoplexes derived from cationic gemini surfactants and lipids was several times superior to the transfection efficiency of corresponding binary lipoplexes, also surpassing standard transfection systems. The overall impact of gemini surfactants into the formation and dynamic of cationic bilayers was found to depend heavily on the presence of colipids, their nature, and amount present in lipoplexes. The study confirmed the possibility of combining the specific properties of pyridinium gemini surfactants and cationic lipids synergistically to obtain efficient synthetic transfection systems with negligible cytotoxicity useful for therapeutic gene delivery. PMID:24377350

  12. Evaluation of mechanical properties and low velocity impact characteristics of balsa wood and urethane foam applied to impact limiter of nuclear spent fuel shipping cask

    International Nuclear Information System (INIS)

    The paper aims to evaluate the low velocity impact responses and mechanical properties of balsa wood and urethane foam core materials and their sandwich panels, which are applied as the impact limiter of a nuclear spent fuel shipping cask. For the urethane foam core, which is isotropic, tensile, compressive, and shear mechanical tests were conducted. For the balsa wood core, which is orthotropic and shows different material properties in different orthogonal directions, nine mechanical properties were determined. The impact test specimens for the core material and their sandwich panel were subjected to low velocity impact loads using an instrumented testing machine at impact energy levels of 1, 3, and 5J. The experimental results showed that both the urethane foam and the balsa wood core except in the growth direction (z-direction) had a similar impact response for the energy absorbing capacity, contact force, and indentation. Furthermore, it was found that the urethane foam core was suitable as an impact limiter material owing to its resistance to fire and low cost, and the balsa wood core could also be strongly considered as an impact limiter material for a lightweight nuclear spent fuel shipping cask

  13. Improved mechanical properties of A 508 class 3 steel for nuclear pressure vessel through steelmaking

    International Nuclear Information System (INIS)

    The present work is concerned with the steelmaking practices which improve the mechanical properties of the A 508 class 3 steel for reactor pressure vessel. Three kinds of steelmaking practices were applied to manufacture the forged heavy wall shell for reactor pressure vessel, that is, the vacuum carbon deoxidation (VCD), modified VCD containing aluminum and silicon-killing. The segregation of the chemical elements through the thickness was quite small so that the variations of the tensile properties at room temperature were small and the anisotropy of the impact properties was hardly observed regardless of the steelmaking practices. The Charpy V-notch impact properties and the reference nil-ductile transition temperature by drop weight test were significantly improved by the modified VCD and silicon-killing as compared with those of the steel by VCD. Moreover, the plane strain fracture toughness values of the materials by modified VCD and silicon-killing practices was much higher than those of the steel by VCD. These were resulted from the fining of austenite grain size. It was observed that the grain size was below 20 microm (ASTM No. 8.5) when using the modified VCD and silicon-killing, compared to 50 microm (ASTM No. 7.0) when using VCD

  14. Impact of soil water property parameterization on atmospheric boundary layer simulation

    Science.gov (United States)

    Cuenca, Richard H.; Ek, Michael; Mahrt, Larry

    1996-03-01

    Both the form of functional relationships applied for soil water properties and the natural field-scale variability of such properties can significantly impact simulation of the soil-plant-atmosphere system on a diurnal timescale. Various input parameters for soil water properties including effective saturation, residual water content, anerobiosis point, field capacity, and permanent wilting point are incorporated into functions describing soil water retention, hydraulic conductivity, diffusivity, sorptivity, and the plant sink function. The perception of the meaning of these values and their variation within a natural environment often differs from the perspective of the soil physicist, plant physiologist, and atmospheric scientist. This article investigates the sensitivity of energy balance and boundary layer simulation to different soil water property functions using the Oregon State University coupled atmosphere-plant-soil (CAPS) simulation model under bare soil conditions. The soil parameterizations tested in the CAPS model include those of Clapp and Hornberger [1978], van Genuchten [1980], and Cosby et al. [1984] using initial atmospheric conditions from June 16, 1986 in Hydrologic Atmospheric Pilot Experiment-Modélisation du Bilan Hydrique (HAPEX-MOBILHY). For the bare soil case these results demonstrate unexpected model sensitivity to soil water property parameterization in partitioning all components of the diurnal energy balance and corresponding boundary layer development.

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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

  17. 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.

  18. 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.

  19. 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.

  20. Efeito do tratamento térmico de envelhecimento na microestrutura e nas propriedades de impacto do aço inoxidável superaustenítico ASTM A 744 Gr. CN3MN Aging heat treatment effect on the microstructure and impact properties of the super-austenitic stainless steel ASTM A 744 Gr. CN3MN

    Directory of Open Access Journals (Sweden)

    Márcio Ritoni

    2010-03-01

    Full Text Available O aço inoxidável superaustenítico ASTM A 744 Gr. CN3MN é aplicado na fabricação de equipamentos que trabalham em ambientes sob corrosão severa com solicitação mecânica. Nesse trabalho, investigou-se a influência do tratamento térmico de envelhecimento na microestrutura e nas propriedades de impacto desse tipo de material. Foram realizados tratamentos térmicos de envelhecimento a 900°C por 1,5; 12; 24; 36 e 48 horas. Ensaios de impacto na temperatura ambiente e a -46°C foram realizados nas amostras tratadas termicamente. As análises microestruturais foram feitas por meio de microscopia eletrônica de varredura e difração de raios X. Concluiu-se que quanto maior a o tempo de exposição do material à temperatura de 900°C, menor é a energia absorvida no impacto. Com 1,5 horas o material apresentou redução na resistência ao impacto de 128 para 25 Joules. O tratamento térmico a 900°C por 48 horas causou a precipitação de algumas fases na matriz austenítica, sendo as mais prováveis: sigma (σ, chi (χ e carboneto M23C6.ASTM A 744 Gr. CN3MN superaustenitic stainless steel is employed in the manufacture of equipments designed to work in severely corrosive environments under mechanical loads. This research investigated the influence of aging heat treatments on the microstructure and impact properties of this type of material. These treatments were carried out at temperature of 900ºC for different periods of time: 1.5; 12; 24; 36 and 48 hours. Impact Charpy tests were conducted at room temperature and -46°C for all heat treated samples. The microstructural analyses were carried out by optical microscopy, scanning electron microscopy and X-ray diffraction. It was concluded that as long as the steel was exposed to 900ºC, the energy absorbed during impact was lower. After 1.5 hours at 900ºC the impact energy dropped from 128 to 25 Joules. The samples heat treated at 900ºC for 48 hours showed precipitation of some phases at

  1. 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.

  2. Environmental Impacts on Spiking Properties in Hodgkin–Huxley Neuron with Direct Current Stimulus

    International Nuclear Information System (INIS)

    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 environment. 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. (cross-disciplinary physics and related areas of science and technology)

  3. 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.

  4. [Investigation of the chain structure and thermal property of xylene solubles of impact polypropylene copolymers].

    Science.gov (United States)

    Luo, Hua-Lin; Zhao, Ying; Wu, Jin-Guang; Wang, Du-Jin

    2012-12-01

    Impact polypropylene copolymers (IPC) are in-situ blends of polypropylene homopolymer and ethylene-alpha-olefin copolymers formed in the reactor, which is a multiphasic complex material with isotactic polypropylene (iPP) as a matrix in which poly(ethylene-alpha-olefin) elastomeric copolymer is finely dispersed, and ethylene-alpha-olefin random copolymer (EPR) acts as an elastomer to improve the impact resistance properties of iPP at room temperature and low temperature. In the present, the content of xylene soluble is used to evaluate the content of EPR rubber phase in IPC. The content, the chain structure, and glass transition temperature (T(g)) of EPR rubber are critical to the toughness of IPC. In the present report, Fourier transform infrared spectroscopy(FTIR), nuclear magnetic resonance (NMR) and differential scanning calorimetry(DSC) were utilized to study the comonomer content, chain structure and thermal property of xylene soluble of two IPC prepared by different catalysts. The results indicated that there are small amount of ethylene-propylene segmented copolymers containing short methylene sequence that is crystallizable in the xylene soluble in addition to the ethylene-propylene random copolymers. And the sequence length of crystallizable methylene group of ethylene-propylene segmented copolymers in these two kinds of xylene soluble is different. The random distribution degree of ethylene and propylene monomer in the ethylene-propylene copolymers in these two kinds of xylene soluble is similar. The xylene soluble with lower content of PPP sequence and higher content of ethylene monomer has lower T(g), which will benefit the improvement of impact resistance property of polypropylene. PMID:23427568

  5. Effect of direct quenching on the microstructure and mechanical properties of the lean-chemistry HSLA-100 steel plates

    International Nuclear Information System (INIS)

    Highlights: → Direct-quenched and tempered (DQT) steels gives better mechanical properties. → Fine Cu and Nb (C, N) precipitates enhance matrix strengthening and tempering resistance. → Boron promotes hardenability, but low temperature Charpy impact toughness gets affected. → Mechanical properties equivalent to HSLA-100 steel is achieved by directly quenched leaner chemistry alloys. - Abstract: The influence of direct quenching on structure-property behavior of lean chemistry HSLA-100 steels was studied. Two laboratory heats, one containing Cu and Nb (C:0.052, Mn:0.99, Cu:1.08, Nb:0.043, Cr:0.57, Ni:1.76, Mo:0.55 pct) and the other containing Cu, Nb and B (C:0.04, Mn:1.02, Cu:1.06, Nb:0.036, Cr:0.87, Ni:1.32, Mo:0.41, B:0.002 percent) were hot-rolled into 25 and 12.5 mm thick plates by varying finish-rolling temperatures. The plates were heat-treated by conventional reheat quenching and tempering (RQT), as well as by direct quenching and tempering (DQT) techniques. In general, direct-quench and tempered plates of Nb-Cu heat exhibited good strength (yield strength ∼ 900 MPa) and low-temperature impact toughness (average: 74 J at -85 deg. C); the Charpy V-notch impact energies were marginally lower than conventional HSLA-100 steel. In Nb-Cu-B heat, impact toughness at low-temperature was inferior owing to boron segregation at grain boundaries. Transmission electron microscopy (TEM) and scanning auger microprobe (SAM) analysis confirmed existence of borocarbides at grain boundaries in this steel. In general, for both the steels, the mechanical properties of the direct-quench and tempered plates were found to be superior to reheat quench and tempered plates. A detailed transmission electron microscopy study revealed presence of fine Cu and Nb (C, N) precipitates in these steels. It was also observed that smaller martensite inter-lath spacing, finer grains and precipitates in direct-quench and tempered plates compared to the reheat quench and tempered plates

  6. Impact toughness and plastic properties of composite layered samples as compared to monolithic ones

    Science.gov (United States)

    Yakovleva, I. L.; Tereshchenko, N. A.; Mirzaev, D. A.; Panov, A. V.; Shaburov, D. V.

    2007-08-01

    Effects of testing conditions on the mechanical properties and fracture of a material in the course of impact loading have been studied. Using steels of various phase compositions (ferritic steel 08Kh18T1 and austenitic steel 10Kh18AG19) tested in a wide temperature range (from 20 to -196°C), the advantage of layered structures has been established as compared to monolithic. It has been shown that the testing of composite samples simulates the loading-affected behavior of the ferritic steel 08Kh18T1 with an inhomogeneous layered microstructure obtained during repeated hot rolling with a reduction of no less than 65%.

  7. 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...

  8. [Impact of directly compressed auxiliary materials on powder property of fermented cordyceps powder].

    Science.gov (United States)

    Chen, Li-Hua; Yue, Guo-Chao; Guan, Yong-Mei; Yang, Ming; Zhu, Wei-Feng

    2014-01-01

    To investigate such physical indexes as hygroscopicity, angle of repose, bulk density, fillibility of compression of mixed powder of directly compressed auxiliary materials and fermented cordyceps powder by using micromeritic study methods. The results showed that spray-dried lactose Flowlac100 and microcrystalline cellulose Avicel PH102 had better effect in liquidity and compressibility on fermented cordyceps powder than pregelatinized starch. The study on the impact of directly compressed auxiliary materials on the powder property of fermented cordyceps powder had guiding significant to the research of fermented cordyceps powder tablets, and could provide basis for the development of fermented cordyceps powder tablets. PMID:24754170

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

    OpenAIRE

    Satyam Verma; Jayakumar, S.

    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...

  10. Experimental Investigation on Physical, Thermal and Spectroscopic Properties of 2-Chlorobenzonitrile: Impact of Biofield Treatment

    OpenAIRE

    Mahendra Kumar Trivedi

    2015-01-01

    2-chlorobenzonitrile (2-ClBN) is widely used in the manufacturing of azo dyes, pharmaceuticals, and as intermediate in various chemical reactions. The aim of present study was to evaluate the impact of biofield treatment on physical, thermal and spectroscopic properties of 2-ClBN. 2-ClBN sample was divided into two groups that served as treated and control. The treated group received Mr. Trivedi’s biofield treatment. Subsequently, the control and treated samples were evaluated using X-r...

  11. 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

  12. 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%.

  13. Systematic satellite observations of the impact of aerosols from passive volcanic degassing on local cloud properties

    Science.gov (United States)

    Ebmeier, S. K.; Mather, T. A.; Sayer, A. M.; Grainger, R. G.; Carboni, E.

    2014-12-01

    Aerosol indirect radiative effects - the alteration of cloud properties by atmospheric aerosol - have a large, but relatively uncertain impact on the Earth's radiative balance. Quantification of volcanic aerosol indirect effects contributes to our understanding of both present-day atmospheric properties and of the pre-industrial baseline necessary to assess aerosol radiative forcing. The impact of emissions from passively degassing volcanoes and minor volcanic explosions are particularly poorly constrained. We present systematic satellite measurements of the time-averaged indirect aerosol effect over several years at multiple active and inactive volcanic islands (Moderate Resolution Imaging Spectroradiometer, 2000-2013 and Advanced Along-Track Scanning Radiometer 2002-2008). Retrievals of aerosol and cloud properties at Kilauea, Yasur and Piton de la Fournaise are rotated about the volcanic vent to be parallel to wind direction, so that average upwind and downwind values can be estimated. The emissions from all three volcanoes, including those from passive degassing, strombolian activity and minor explosions lead to measurably increased aerosol optical depth (<0.1) and decreased cloud droplet effective radius (<8 μm) downwind of the volcanoes. Furthermore, Top of Atmosphere Short Wave flux from NASA's Clouds and the Earth's Radiant Energy System (CERES) show downwind perturbations ranging from 10 to 45 Wm-2 within 400 km of degassing volcanoes. Comparison of these observations to cloud properties at isolated islands without degassing volcanoes demonstrates that these patterns are not purely orographic in origin. Our observations of unpolluted, isolated marine settings may capture processes similar to those in the pre-industrial marine atmosphere.

  14. IMPACT OF IRRADIATION AND THERMAL AGING ON DWPF SIMULATED SLUDGE PROPERTIES

    International Nuclear Information System (INIS)

    The research and development programs in support of the Defense Waste Processing Facility (DWPF) and other high-level waste vitrification processes require the use of both nonradioactive waste simulants and actual waste samples. While actual waste samples are the ideal materials to study, acquiring large quantities of actual waste is difficult and expensive. Tests utilizing actual high-level waste require the use of expensive shielded cells facilities to provide sufficient shielding for the researchers. Nonradioactive waste simulants have been used for laboratory testing, pilot-scale testing and full-scale integrated facility testing. These waste simulants were designed to reproduce the chemical and, if possible, the physical properties of the actual high-level waste. This technical report documents a study on the impact of irradiating a Sludge Batch 3 (SB3) simulant and of additional tests on aging a SB3 simulant by additional thermal processing. Prior simulant development studies examined methods of producing sludge and supernate simulants and processes that could be used to alter the physical properties of the simulant to more accurately mimic the properties of actual waste. Development of a precipitated sludge simulant for the River Protection Project (RPP) demonstrated that the application of heat for a period of time could significantly alter the rheology of the sludge simulant. The RPP precipitated simulant used distillation to concentrate the sludge solids and produced a reduction in sludge yield stress of up to 80% compared to the initial sludge properties. Observations at that time suggested that a substantial fraction of the iron hydroxide had converted to the oxide during the distillation. DWPF sludge simulant studies showed a much smaller reduction in yield stress (∼10%), demonstrated the impact of shear on particle size, and showed that smaller particle sizes yielded higher yield stress products. The current study documented in this report focuses

  15. 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. PMID:27137806

  16. 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.

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

    Science.gov (United States)

    Auroy, M.; Poyet, S.; Le Bescop, P.; Torrenti, J.-M.

    2013-07-01

    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.

  18. Impact of carbonation on the durability of cementitious materials: Water transport properties characterization

    International Nuclear Information System (INIS)

    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. (authors)

  19. Laser Peening Process and Its Impact on Materials Properties in Comparison with Shot Peening and Ultrasonic Impact Peening

    Directory of Open Access Journals (Sweden)

    Abdullahi K. Gujba

    2014-12-01

    Full Text Available The laser shock peening (LSP process using a Q-switched pulsed laser beam for surface modification has been reviewed. The development of the LSP technique and its numerous advantages over the conventional shot peening (SP such as better surface finish, higher depths of residual stress and uniform distribution of intensity were discussed. Similar comparison with ultrasonic impact peening (UIP/ultrasonic shot peening (USP was incorporated, when possible. The generation of shock waves, processing parameters, and characterization of LSP treated specimens were described. Special attention was given to the influence of LSP process parameters on residual stress profiles, material properties and structures. Based on the studies so far, more fundamental understanding is still needed when selecting optimized LSP processing parameters and substrate conditions. A summary of the parametric studies of LSP on different materials has been presented. Furthermore, enhancements in the surface micro and nanohardness, elastic modulus, tensile yield strength and refinement of microstructure which translates to increased fatigue life, fretting fatigue life, stress corrosion cracking (SCC and corrosion resistance were addressed. However, research gaps related to the inconsistencies in the literature were identified. Current status, developments and challenges of the LSP technique were discussed.

  20. Estimation of mechanical properties of cast stainless steels during thermal aging in LWR systems

    International Nuclear Information System (INIS)

    A procedure and correlations are presented for predicting Charpy- impact energy, tensile flow stress, fracture toughness J-R curve, and JIC of aged cast stainless steels from known material information. The ''saturation'' impact strength and fracture toughness of a specific cast stainless steel, i.e., the minimum value that would be achieved for the material after long-term service, is estimated from the chemical composition of the steel. Mechanical properties as a function of time and temperature of reactor service are estimated from impact energy and flow stress of the unaged material and the kinetics of embrittlement, which are also determined from chemical composition. The JIC values are determined from the estimated J-R curve and flow stress. Examples of estimating mechanical properties of cast stainless steel components during reactor service are presented. A common ''lower-bound'' J-R curve for cast stainless steels of unknown chemical composition is also defined for a given grade of steel, ferrite content, and temperature

  1. Estimation of mechanical properties of cast stainless steels during thermal aging in LWR systems

    International Nuclear Information System (INIS)

    A procedure and correlations are presented for predicting Charpy-impact energy, tensile flow stress, fracture toughness J-R curve, and JIC of aged cast stainless steels from known material information. The ''saturation'' impact strength and fracture toughness of a specific cast stainless steel, i.e., the minimum value that would be achieved for the material after long-term service, is estimated from the chemical composition of the steel. Mechanical properties as a function of time and temperature of reactor service are estimated from impact energy and flow stress of the unaged material and the kinetics of embrittlement, which are also determined from chemical composition. The JIC values are determined from the estimated J-R curve and flow stress. Examples of estimating mechanical properties of cast stainless steel components during reactor service are presented. A common predicted lower-bound J-R curve for cast stainless steels of unknown chemical composition is also defined for a given grade of steel, ferrite content, and temperature

  2. Thermal aging of cast stainless steels in LWR systems: Estimation of mechanical properties

    International Nuclear Information System (INIS)

    A procedure and correlations are presented for predicting Charpy-impact energy, tensile flow stress, fracture toughness J-R curve, and JIC of aged cast stainless steels from known material information. The ''saturation'' impact strength and fracture toughness of a specific cast stainless steel, i.e., the minimum value that would be achieved for the material after long-term service, is estimated from the chemical composition of the steel. Mechanical properties as a function of time and temperature of reactor service are estimated from impact energy and flow stress of the unaged material and the kinetics of embrittlement, which are also determined from chemical composition. The JIC values are determined from the estimated J-R curve and flow stress. Examples of estimating mechanical properties of cast stainless steel components during reactor service are presented. A common ''lower-bound'' J-R curve for cast stainless steels of unknown chemical composition is also defined for a given grade of steel, ferrite content, and temperature

  3. Precipitation strengthening and mechanical properties of ultra low carbon bainitic steel with Cu addition

    International Nuclear Information System (INIS)

    Effect of ageing parameters on tensile properties and impact energy of ultra low carbon bainitic steel (ULCB) was established. The investigated HN3MCu1.5 steel belongs to a new group of structural steels, which are going to be applied for constructions working at low temperatures.. The chemical composition of the steel is given. The microstructure of the steel after ageing at temperature 640oC during to 100 hours was observed by optical and electron microscopy. Special attention was paid to study primary austenite grain size, which determines the average diameter of bainite-martensite packet size and thus the impact transition temperature according to empirical equations. Then the quantitative determination of the average diameter of precipitates and the interparticle spacing was studied to calculate the precipitation strengthening effect on yield strength. The empirical equation, which relates effect of ageing time to the yield strength was determined. It was established that the optimum mechanical properties of HN3MCu1.5 steel aged at 649oC are achieved for ageing time in the range of 1 - 10 hours. For the above ageing parameters the investigated steels had: YS = 700-661 MPa, TS = 814-741 MPa and impact energy KCV = 150-170 J determined on Charpy V specimens at temperature -80oC. (author)

  4. Investigations on the impact strength of constructional high-strength Weldox steel at lowered temperature

    Directory of Open Access Journals (Sweden)

    W. Ozgowicz

    2008-08-01

    Full Text Available Purpose: The paper presents the results of investigations concerning the impact strength of thick steel plates at lowered temperature obtained by industrial smelting of micro-alloyed steel of the type S1100QL (Weldox 1100 and S1300QL (Weldox 1300 with a yield strength of 1100-1300 MPa.Design/methodology/approach: The main methods used for these researches were the impact test Charpy V at lower temperatures, and metallographic observations. The tested samples at lower temperature have also been analyzed fractographically.Findings: The influence of the chemical composition and technology of production on the structure and mechanical properties of the investigated kinds of steels have been determined, as well as their ductility temperature of transition into the brittle state.Research limitations/implications: A large dispersion of intermetallic precipitated phases restricted considerably the possibility of their metallographic identification. This latter one will be done in the next stage of basic investigations.Practical implications: A wide range of practical applications of Weldox 1100 and Weldox 1300 sheet plates is warranted by both their high impact strength, especially at lower temperatures, and lower ductility transition temperature.Originality/value: It has been found that the degree of refinement of the martensitic structure and dispersion of secondary precipitations, mainly carbides and niobium nitrocarbides affect considerably the change of the impact strength within the investigated range of temperature from ambient temperature to minus 150°C.

  5. Effects of heat treatment conditions on the microstructure and impact properties of EUROFER 97 ODS steel

    International Nuclear Information System (INIS)

    Probably the most important range of materials to consider for the blanket material in the tokamak design for fusion reactors such as ITER and DEMO is the high alloy Fe9Cr oxide dispersion strengthened (ODS) ferritic steels. These steels possess exceptional thermal conductivity and low thermal expansion while being strongly resistant to void swelling. Their main drawback is the high ductile-to-brittle transition temperature (DBTT), particularly in the ODS versions of the material. This paper describes attempts that are being made to reduce this DBTT in as yet unirradiated materials by a novel heat treatment procedure. The principle behind this approach is that low DBTT in the unirradiated materials will lead to relatively low DBTT even in He-containing material that has been irradiated with fusion blanket-type irradiations. New batches of high alloy Fe9Cr ODS (EUROFER) ferritic steel have been produced by a powder metallurgical route, and relatively homogeneous material has been produced by a hot isostatic pressing procedure. Mini-Charpy test specimens were made from materials that had been subjected to a matrix of heat treatments designed to show up variations in solution treatment (ST) temperature, cooling rate from the ST temperature and tempering treatment. The initial DBTT was in the range 150-200 °C. Extremely interesting results have been obtained. DBTT downward shifts of up to 200 °C have been observed by using a high 1300 °C ST temperature and a low cooling rate. The paper goes on to describe the microstructure of this material, and discusses the possible microstructural factors needed to produce these very high DBTT downward shifts. Low dissolved carbon and higher proportions of low-angle grain boundaries seem to provide the key to the understanding of the alloy behaviour.

  6. Effect of intercritical annealing treatment on the mechanical properties of SA106 Gr.C piping steel

    International Nuclear Information System (INIS)

    It is reported that SA106 Gr.C piping steel generally exhibits not enough toughness to apply LBB concept and needs a suitable additional heat treatment to improve the toughness. The intercritical annealing at the (α+γ) phase temperature at 760 deg C for 40 min was performed in this study. To evaluate the improved material properties with the heat treatments, tensile tests were carried out under various temperatures, from RT to 350 deg C, and strain rates, from 1.39x10-4s-1 to 1.39x10-2s-1. Also, Charpy impact tests were conducted to measure impact toughness at room temperature. The manifestations of dynamic strain aging (DSA) were observed in the tensile properties. However, the magnitude of serration and the strength increased by DSA was relatively small compared to similar grade carbon steels. The intercritical annealing was able to increase the impact toughness by 1.5 times compared to as-received material. The dissolved carbon content in the retained ferrite, which was formed at the (α+γ) region, may be lower than that in the transformed ferrite, which was formed at the pearlite transformation temperature. It is considered that the cleaner retained ferrite may have caused the higher impact toughness and ductility in addition to the general toughening due to finer grain sizes, which were resulted from the heat treatment

  7. Impacts of land use changes on physical and chemical soil properties in the Central Pyrenees

    Science.gov (United States)

    Nadal Romero, Estela; Hoitinga, Leo; Valdivielso, Sergio; Pérez Cardiel, Estela; Serrano Muela, Pili; Lasanta, Teodoro; Cammeraat, Erik

    2015-04-01

    Soils and vegetation tend to evolve jointly in relation to climate evolution and the impacts of human activity. Afforestation has been one of the main policies for environmental management of forest landscapes in Mediterranean areas. Afforestation has been based mainly on conifers because they are fast-growing species, and also because it was believed that this would lead to rapid restoration of soil properties and hydrological processes, and the formation of protective vegetation cover. This study analyses the effects of afforestation on physical and chemical soil properties. Specifically, we addressed this research question: (i) How do soil properties change after land abandonment? The 11 microsites considered were: Afforestation Pinus sylvestris (escarpment, terrace and close to the stem), Afforestation Pinus nigra (escarpment, terrace and close to the stem), natural shrubland, grasslands, bare lands, and undisturbed forest site (pine cover and close to the stem). An extensive single sampling was carried out in September 2014. We systematically collected 5 top soil samples (0-10 cm) and 3 deep soil samples (10-20 cm) per microsite (88 composite samples in total). These properties were analysed: (i) soil texture, (ii) bulk density, (iii) pH and electrical conductivity, (iv) total SOC, (v) Total Nitrogen, (vi) organic matter, (vii) CaCO3 and (viii) aggregate stability. Statistical tests have been applied to determine relationships between the different soil properties and are used to assess differences between different soil samples, land use areas and soil depths. Implications of reafforestation for soil development and environmental response are discussed. Acknowledgments This research was supported by a Marie Curie Intra-European Fellowship in the project "MED-AFFOREST" (PIEF-GA-2013-624974).

  8. Correlation of particle impact conditions with bonding, nanocrystal formation and mechanical properties in kinetic sprayed nickel

    International Nuclear Information System (INIS)

    Owing to the specific high-strain-rate thermomechanical characteristics of Ni particle impact in kinetic spraying, the rebound phenomenon of the impacting particles hinders the formation of the first layer and impedes successful build-up of the coating. Even at higher impact velocities, the deposition efficiency of the coating is quite low because of excessive kinetic energy, which induces the rebound and/or erosion of the highly flattened particles. This paper reports noticeably improved bonding and deposition characteristics of Ni particles resulting from suppressed equivalent (von Mises) flow stress and enhanced interface heat-up as a result of powder preheating. Experimental observations coupled with finite-element modeling (FEM) corroborate the fact that the thermally softened Ni particle is very effective for enhanced adhesive and cohesive bonding. Based on the FEM results, the thermal boost-up zone, increased by thermally accelerated adiabatic shear instability, is proposed as a crucial factor for enhancing bonding between the particles, which is essential in producing better coating properties. Moreover, nanocrystal formation (<100 nm) in the coating was more pronounced than cases previously reported in the literature, mainly because of the enhanced thermal activation and straining of the severely deformed particles, which was verified by transmission electron microscopy investigations and nanoindentation tests.

  9. Impact of wheeled and tracked tractors on soil physical properties in a mixed conifer stand

    Directory of Open Access Journals (Sweden)

    Cambi M

    2016-02-01

    Full Text Available Damage to forest soil caused by vehicle traffic mainly consists of soil compaction, displacement, and rut formation. Severity of the damage depends on vehicle mass, weight of the carried loads, ground morphology, and soil properties, such as moisture. This paper investigates the impacts of two types of vehicles (tracked or wheeled tractor, traffic intensities (one or five skidding cycles and soil moisture (24% or 13% by weight on compaction of a loam textured soil in a mixed conifer stand of central Italy. Changes in porosity, bulk density, shear and penetration resistances were analyzed. The latter three parameters were significantly higher in the trafficked soil portions than in the undisturbed ones in all treatments, while the opposite was true for porosity. The impact on soil bulk density and porosity was stronger for the wheeled tractor working on moist soil, while no significant effect of soil moisture was recorded for the tracked tractor. Shear and penetration resistances increased as a consequence of traffic, depending on both tractor type and soil moisture. The largest impact on shear resistance was recorded for the wheeled tractor on moist soil, while significant differences in penetration resistance were observed only between tracked and wheeled tractors in dry soil conditions. In order to preserve soil quality during logging activities, we recommend to operate under dry soil conditions and to limit vehicle movement on existing or new planned trails.

  10. New insights into the properties of contrail cirrus and their impact on climate from airborne experiments

    Science.gov (United States)

    Voigt, Christiane; Schumann, Ulrich; Minikin, Andreas; Schlager, Hans; Anderson, Bruce

    2016-04-01

    Current growth rates in aviation demand a profound scientific data base of contrail cirrus properties in order to accurately assess their climate impact. In particular, the differentiation of contrail cirrus in natural cirrus fields is challenging. Direct observations of contrail cirrus throughout their life cycle are scarce and therefore limit our understanding of the climate effects from contrail cirrus. Here, we give new insights into the growth, life-cycle and climate impact from contrail cirrus based on results from suite of aircraft experiments. NASA's ACCESSII mission focused on the detection of aircraft emissions and initial contrail stages. Nascent contrails were detected at cruise altitudes at 100 m distance to the engine exit. Contrail growth to 10-min contrail age was investigated during DLR's CONCERT campaigns. Finally, the objective of the ML-CIRRUS experiment was to study the life cycle and climate impact of contrail cirrus. The contrail measurements are related to previous observations and discussed in the context of recent developments in contrail modeling. Highlights include the quantification of the effects of aircraft type on contrail microphysics, the analysis of ice particle shapes and the quantitative distinction of contrail cirrus and natural cirrus.

  11. 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.

  12. 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. PMID:26604353

  13. Influence of Y2O3 and Fe2Y additions on the formation of nano-scale oxide particles and the mechanical properties of an ODS RAF steel

    International Nuclear Information System (INIS)

    The main goal of this work was to manufacture an oxide dispersion strengthened (ODS) reduced activation ferritic steel from a pre-alloyed, gas atomised Fe-14Cr-2W-0.2Ti (in wt.%) powder mechanically alloyed with either 0.3%Y2O3 or 0.5%Fe2Y particles and consolidated by hot isostatic pressing, and to investigate its microstructure, microhardness and Charpy impact properties. A lower oxygen content was measured in the ODS Fe2Y steel than in the ODS Y2O3 steel. However, the mean size of nanoclusters in the ODS Fe2Y steel was found larger, whereas density was smaller, than in the ODS Y2O3 steel. In addition, the nanoclusters in the ODS Fe2Y steel appear less stable upon thermal annealing at 1350 oC for 1 h. Vickers microhardness measurements revealed that after HIPping the ODS Y2O3 is about 40% harder (366 HV0.1) than the ODS Fe2Y (260 HV0.1). After heat treatment at 1350 deg. C the microhardness of both alloys was found smaller by about 30%. The ODS Fe2Y steel was found to exhibit a much better Charpy impact behaviour, with an upper shelf energy of 8.8 J and a ductile-to-brittle transition temperature of -24 deg. C. The differences in mechanical properties were discussed in terms of the oxygen content as well as in the mean size, number density and crystallographic structure of the nanoclusters.

  14. Effect of post-weld heat treatment on the mechanical properties of electron beam welded joints for CLAM steel

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Qingsheng, E-mail: chunjing.li@fds.org.cn; Zheng, Shuhui; Liu, Shaojun; Li, Chunjing; Huang, Qunying

    2013-11-15

    In this paper the microstructure and mechanical properties of electron beam weld (EBW) joints for China low activation martensitic (CLAM) steel, which underwent a series of different post weld heat treatments (PWHTs) were studied. The aim of the study was to identify suitable PWHTs that give a good balance between strength and toughness of the EBW joints. The microstructural analyses were performed by means of optical microscope (OM) and scanning electron microscope (SEM). The mechanical properties were determined via tensile tests and Charpy impact tests. The results showed that the tensile strength of the as-weld joint (i.e. without any PWHT) were close to that of the base metal, but the impact toughness was only 13% of that of the base metal due to the existence of a delta-ferrite microstructure. To achieve a significant improvement in toughness a PWHT needs to be performed. If a one-step PWHT is applied tempering at 760 °C for 2 h gives EBW joints with high strength at a still acceptable toughness level. If a two-step PWHT is applied, a process involving quenching at 980 °C for 0.5 h followed by tempering at 740 °C or 760 °C for 2 h gives EBW joints with high strength and toughness properties. Whenever possible a two-step PWHT should be applied in favor of a one-step process, because of higher resulting strength and toughness properties.

  15. Effect of post-weld heat treatment on the mechanical properties of electron beam welded joints for CLAM steel

    Science.gov (United States)

    Wu, Qingsheng; Zheng, Shuhui; Liu, Shaojun; Li, Chunjing; Huang, Qunying

    2013-11-01

    In this paper the microstructure and mechanical properties of electron beam weld (EBW) joints for China low activation martensitic (CLAM) steel, which underwent a series of different post weld heat treatments (PWHTs) were studied. The aim of the study was to identify suitable PWHTs that give a good balance between strength and toughness of the EBW joints. The microstructural analyses were performed by means of optical microscope (OM) and scanning electron microscope (SEM). The mechanical properties were determined via tensile tests and Charpy impact tests. The results showed that the tensile strength of the as-weld joint (i.e. without any PWHT) were close to that of the base metal, but the impact toughness was only 13% of that of the base metal due to the existence of a delta-ferrite microstructure. To achieve a significant improvement in toughness a PWHT needs to be performed. If a one-step PWHT is applied tempering at 760 °C for 2 h gives EBW joints with high strength at a still acceptable toughness level. If a two-step PWHT is applied, a process involving quenching at 980 °C for 0.5 h followed by tempering at 740 °C or 760 °C for 2 h gives EBW joints with high strength and toughness properties. Whenever possible a two-step PWHT should be applied in favor of a one-step process, because of higher resulting strength and toughness properties.

  16. 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.

  17. Evolution of mechanical properties of silicate glasses: Impact of the chemical composition and effects of irradiation

    International Nuclear Information System (INIS)

    This thesis examines: (1) how the chemical composition changes the hardness, toughness, and stress corrosion cracking behavior in model pristine and (2) how external irradiation impact these properties. It is to be incorporated in the context of the storage of nuclear waste in borosilicate glass matrix, the structural integrity of which should be assessed. Eight simplified borosilicate glasses made of 3 oxides with modulated proportions (SiO2-B2O3-Na2O (SBN) have been selected and their hardness, toughness, and stress corrosion cracking behavior have been characterized prior and after irradiation. The comparative study of the non-irradiated SBN glasses provides the role played by the chemical composition. The sodium content is found to be the key parameter: As it increases, the glass plasticity increases, leading to changes in the mechanical response to strain. Hardness (Hv) and toughness (Kc) decrease since the flow under indenter increases. The analysis of the stress corrosion behavior evidences a clear shift of the SCC curves linked also to the glass plasticity. Four of the 8 simplified SBN glass systems highlight the influence of electron, light and heavy ions irradiations on the mechanical properties. Once again, the sodium content is a key parameter. It is found to inhibit the glass modification: Glasses with high sodium content are more stable. Ions irradiations highlight the predominant role of nuclear interaction in changing the glass properties. Finally, electronic interaction induced by helium and electron irradiation does not lead to the same structural/mechanical glasses variations. (author)

  18. 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.

  19. Impact of carbonation on water transport properties of cement-based materials

    International Nuclear Information System (INIS)

    Cement-based materials would be commonly used for nuclear waste management and, particularly for geological disposal vaults as well as containers in France. Under service conditions, the structures would be subjected to simultaneous drying and carbonation. Carbonation relates to the reaction between CO2 and the hydrated cement phases (mainly portlandite and C-S-H). It induces mineralogical and microstructural changes (due to hydrates dissolution and calcium carbonate precipitation). It results in transport properties modifications, which can have important consequences on the durability of reinforced concrete structures. Concrete durability is greatly influenced by water: water is necessary for chemical reactions to occur and significantly impacts transport. The evaluation of the unsaturated water transport properties in carbonated materials is then an important issue. That is the aim of this study. A program has been established to assess the water transport properties in carbonated materials. In this context, four mature hardened cement pastes (CEM I, CEM III/A, CEM V/A according to European standards and a Low-pH blend) are carbonated. Accelerated carbonation tests are performed in a specific device, controlling environmental conditions: (i) CO2 content of 3%, to ensure representativeness of the mineralogical evolution compared to natural carbonation and (ii) 25 C. degrees and 55% RH, to optimize carbonation rate. After carbonation, the data needed to describe water transport are evaluated in the framework of simplified approach. Three physical parameters are required: (1) the concrete porosity, (2) the water retention curve and, (3) the effective permeability. The obtained results allow creating link between water transport properties of non-carbonated materials to carbonated ones. They also provide a better understanding of the effect of carbonation on water transport in cementitious materials and thus, complement literature data. (authors)

  20. The influence of sintering time on the properties of PM duplex stainless steel

    Directory of Open Access Journals (Sweden)

    Z. Brytan

    2009-12-01

    Full Text Available Purpose: The purpose of this paper is to analyse the effect of sintering time on the pore morphology, microstructural changes, tensile properties and corrosion resistance of vacuum sintered duplex stainless steel.Design/methodology/approach: In presented study PM duplex stainless steels were obtained through mixing base ferritic stainless steel powder with controlled addition of elemental alloying powders and then sintered in a vacuum furnace with argon backfilling at 1250°C for different time periods. Produced materials were studied by LOM/SEM metallography and the pore morphology was characterized. The mechanical properties were studied in tensile, hardness and Charpy impact tests. The corrosion resistance was evaluated by means of salt spray test and immersion in sulfuric acid.Findings: Prolongation of sintering time influenced on increase of density thus on the mechanical properties and microstructure balance.Practical implications: Mechanical properties of obtained PM duplex stainless steels are very promising, especially with the aim of extending their field of possible applications.Originality/value: The possibility of obtaining balanced austenitic-ferritic microstructure of stainless steel using elemental powders added to a stainless steel base powder. The vacuum sintering of such powder mixture results in good microstructural homogeneity.

  1. 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.

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

    International Nuclear Information System (INIS)

    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

  3. 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

  4. Investigations on the impact strength of constructional high-strength Weldox steel at lowered temperature

    OpenAIRE

    W. Ozgowicz; E. Kalinowska-Ozgowicz

    2008-01-01

    Purpose: The paper presents the results of investigations concerning the impact strength of thick steel plates at lowered temperature obtained by industrial smelting of micro-alloyed steel of the type S1100QL (Weldox 1100) and S1300QL (Weldox 1300) with a yield strength of 1100-1300 MPa.Design/methodology/approach: The main methods used for these researches were the impact test Charpy V at lower temperatures, and metallographic observations. The tested samples at lower temperature have also b...

  5. 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.

  6. Impacts of lawn-care pesticides on aquatic ecosystems in relation to property value

    International Nuclear Information System (INIS)

    To determine the potential impacts of lawn-care pesticides on aquatic ecosystems, the macroinvertebrate communities of six streams were assessed using a multimetric approach. Four streams flowed through residential neighborhoods of Peachtree City, GA, USA, with differing mean property values and two reference streams were outside the city limits. A series of correlation analyses were conducted comparing stream rank from water quality and physical stream parameters, habitat assessments, benthic macroinvertebrate metric, pesticide toxicity and metal toxicity data to determine relationships among these parameters. Significant correlations were detected between individual analyses of stream rank for pesticide toxicity, specific conductance, turbidity, temperature and dissolved oxygen with benthic macroinvertebrate metrics. - The macroinvertebrate communities of suburban streams may be influenced by the toxicity of the pesticides present in the water and sediment as well as select water quality parameters

  7. IMPACT OF THERMAL TREATMENT ON THE PROPERTIES OF THE PROTEIC FOAMS

    Directory of Open Access Journals (Sweden)

    Alain Riaublanc

    2011-02-01

    Full Text Available The food foams are "whipped" products that have recently experienced significant growth in the food industry. They are appreciated by consumers for their creamy texture, taste and visual aspect. Whey proteins are particularly common ingredients in the formulation of food foams because of their functional properties (foaming properties, interfacial, emulsifying. Denaturation and aggregation of whey proteins further to a heat treatment, allows the improvement of these properties by creating protein aggregates with targeted properties. The objective of this study is to understand the impact of the intensity of heat treatment applied to a protein solution on the aggregation of proteins (proportion, size and morphology of protein assemblies and on their foaming properties in order to better control the use properties of foamed products stabilized by whey protein aggregates (WPI. In this work, a 2% w/v of whey proteins in the presence of salt (50 mM NaCl was heated in an Actijoule type tubular heat exchanger at 80, 90 and 100 °C. Native and denatured solutions of WPI were characterized by microcalorimetry ( DSC, size exclusion chromatography (SEC, diffusion light scattering (DLS, electrophoresis (SDS-PAGE, optical microscopy and atomic force microscopy (AFM. To assess the impact of thermal treatment on the foaming ability of protein solutions, a bubbling method has been employed. The experimental results showed that as far as the heating temperature is increased, it promotes the aggregation of proteins into oligomers which then are forming soluble aggregates of about 160 nm in diameter. We have also observed that the increase of this fraction is a continuous function of temperature for solutions treated up to 100 °C. However, the amount of insoluble aggregates formed reaches a maximum when the heat treatment temperature is 90 °C. Finally, we showed by SDS-PAGE that the soluble and insoluble aggregates are stabilized by disulfide bridges and

  8. Impacts of hematite nanoparticle exposure on biomechanical, adhesive, and surface electrical properties of Escherichia coli cells.

    Science.gov (United States)

    Zhang, Wen; Hughes, Joseph; Chen, Yongsheng

    2012-06-01

    Despite a wealth of studies examining the toxicity of engineered nanomaterials, current knowledge on their cytotoxic mechanisms (particularly from a physical perspective) remains limited. In this work, we imaged and quantitatively characterized the biomechanical (hardness and elasticity), adhesive, and surface electrical properties of Escherichia coli cells with and without exposure to hematite nanoparticles (NPs) in an effort to advance our understanding of the cytotoxic impacts of nanomaterials. Both scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that E. coli cells had noticeable deformation with hematite treatment for 45 min with a statistical significance. The hematite-treated cells became significantly harder or stiffer than untreated ones, as evidenced by indentation and spring constant measurements. The average indentation of the hematite-treated E. coli cells was 120 nm, which is significantly lower (P hematite-treated E. coli cells (0.28 ± 0.11 nN/nm) was about 20 times higher than that of untreated ones (0.01 ± 0.01 nN/nm). The zeta potential of E. coli cells, measured by dynamic light scattering (DLS), was shown to shift from -4 ± 2 mV to -27 ± 8 mV with progressive surface adsorption of hematite NPs, a finding which is consistent with the local surface potential measured by Kelvin probe force microscopy (KPFM). Overall, the reported findings quantitatively revealed the adverse impacts of nanomaterial exposure on physical properties of bacterial cells and should provide insight into the toxicity mechanisms of nanomaterials. PMID:22467500

  9. 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. PMID:26087015

  10. 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

  11. The impact of algal properties and pre-oxidation on solid-liquid separation of algae.

    Science.gov (United States)

    Henderson, Rita; Parsons, Simon A; Jefferson, Bruce

    2008-04-01

    Algae are traditionally classified according to biological descriptors which do not give information on surface characteristics that are important with respect to removal by water treatment processes. This review examines the character of freshwater algal populations from a water treatment perspective and evaluates the impact of their varying properties and the use of pre-oxidation on their removal by solid-liquid separation processes.. The characteristics shown to impact on treatment were morphology, motility, surface charge, cell density and the extracellular organic matter (EOM) composition and concentration. With the exception of density, these are not phyla specific. It was also shown that dissolved air flotation (DAF) was the most robust clarification method, where up to 99.8% removal was achieved compared to 94% for sedimentation when using metal coagulants. However, successful clarification relied heavily on the optimisation of preceding coagulation and flocculation and coagulant demand was important in this respect. Comparison of all available data reveals a relationship between cell surface area and coagulant demand. It is thus suggested that cell surface area would provide a basis for regrouping algae such that the classification is informative with respect to water treatment. However, the absolute coagulant demand is a result of both surface area and EOM influences. The latter are relatively poorly understood in comparison to natural organic matter (NOM) systems and this remains a limit in current knowledge. PMID:18261761

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

    International Nuclear Information System (INIS)

    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.

  13. Impact tensile properties and strength development mechanism of glass for reinforcement fiber

    International Nuclear Information System (INIS)

    In this study, impact tensile properties of E-glass were investigated by fiber bundle testing under a high strain rate. The impact tests were performed employing two types of experiments. One is the tension-type split Hopkinson pressure bar system, and the other is the universal high-speed tensile-testing machine. As the results, it was found that not only the tensile strength but also the fracture strain of E-glass fiber improved with the strain rate. The absorbed strain energy of this material significantly increased. It was also found that the degree of the strain rate dependency of E-glass fibers on the tensile strength was varied according to fiber diameter. As for the strain rate dependency of the glass fiber under tensile loading condition, change of the small crack-propagation behaviour was considered to clarify the development of the fiber strength. The tensile fiber strength was estimated by employing the numerical simulation based on the slow crack-growth model (SCG). Through the parametric study against the coefficient of the crack propagation rate, the numerical estimation value was obtained for the various testing conditions. It was concluded that the slow crack-growth behaviour in the glass fiber was an essential for the increase in the strength of this material

  14. 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.

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

    Science.gov (United States)

    Shahali, Y.; Pourpak, Z.; Moin, M.; Zare, A.; Majd, A.

    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.

  16. Impact tensile properties and strength development mechanism of glass for reinforcement fiber

    Science.gov (United States)

    Kim, T.; Oshima, K.; Kawada, H.

    2013-07-01

    In this study, impact tensile properties of E-glass were investigated by fiber bundle testing under a high strain rate. The impact tests were performed employing two types of experiments. One is the tension-type split Hopkinson pressure bar system, and the other is the universal high-speed tensile-testing machine. As the results, it was found that not only the tensile strength but also the fracture strain of E-glass fiber improved with the strain rate. The absorbed strain energy of this material significantly increased. It was also found that the degree of the strain rate dependency of E-glass fibers on the tensile strength was varied according to fiber diameter. As for the strain rate dependency of the glass fiber under tensile loading condition, change of the small crack-propagation behaviour was considered to clarify the development of the fiber strength. The tensile fiber strength was estimated by employing the numerical simulation based on the slow crack-growth model (SCG). Through the parametric study against the coefficient of the crack propagation rate, the numerical estimation value was obtained for the various testing conditions. It was concluded that the slow crack-growth behaviour in the glass fiber was an essential for the increase in the strength of this material.

  17. Characterisation of weldment hardness, impact energy and microstructure in API X65 steel

    International Nuclear Information System (INIS)

    The variation of microstructure and mechanical properties in various sub-zones of double submerged arc welded line pipe steel of grade API X65 was investigated. Instrumented Charpy V-notch tests and Vickers hardness experiments were conducted on the fusion zone, base metal and heat affected zone of the weld joint in 14.3 mm thick, 1219 mm outside diameter spiral pipeline. The lowest impact energy and the highest hardness level (160J and 218 HV, respectively) were recorded in the fusion zone. The low energy and high hardness characteristics of the seam weld can be attributed to its cast microstructure and the presence of grain boundary phases (such as proeutectoid ferrite), confirmed by standard metallographic observation. Despite this, service requirements set by the API 5L industry code (minimum impact energy of 73J, maximum hard spots of 350 HV) were fulfilled by the tested steel. Highlights: ► Experimental study of API X65 steel microstructure. ► Analysis of the relationship between X65 steel microstructure and hardness. ► Analysis of the relationship between X65 steel microstructure and impact energy. ► Presentation of detailed technical information on DSA welding in spiral pipes.

  18. Impact Toughness of 0.2 Pct C-1.5 Pct Si-(1.5 to 5) Pct Mn Transformation-Induced Plasticity-Aided Steels with an Annealed Martensite Matrix

    Science.gov (United States)

    Tanino, Hikaru; Horita, Masaomi; Sugimoto, Koh-Ichi

    2016-05-01

    The impact properties of 0.2 pct C-1.5 pct Si-(1.5 to 5) pct Mn transformation-induced plasticity (TRIP)-aided steels with an annealed martensite matrix which had been subjected to isothermal transformation after inter-critical annealing were investigated for potential automotive applications. The impact properties are related to the retained austenite characteristics of the steels. The products of tensile strength (TS) and Charpy impact absorbed value (CIAV) were the same for the 1.5 and 5 pct Mn steels, although the ductile-brittle transition temperature was higher for the latter. The impact properties of the 3 pct Mn steel were worse than these two steels. The high TS × CIAV value for the 5 pct Mn steel at 293 K (25 °C) was mainly caused by the TRIP effect of a larger amount of retained austenite (36 vol pct) and the hardened matrix structure; low retained austenite stability and/or a hard martensite-austenite phase reduced this value. The higher ductile-brittle transition temperature of the 5 pct Mn steel was associated with Mn segregation, a large amount of unstable retained austenite on prior austenitic grain boundaries, and decreased cleavage fracture stress owing to the high Mn content.

  19. Visualization of impact damaging of carbon/epoxy panels

    Science.gov (United States)

    Boccardi, Simone; Boffa, Natalino Daniele; Carlomagno, Giovanni Maria; Meola, Carosena; Ricci, Fabrizio

    2016-05-01

    This work is concerned with impact damaging of carbon/epoxy materials. Specimens of different thickness are herein considered, which involve several fibers orientations and stacking sequences. Impact tests are carried out at different energies with a modified Charpy pendulum. The specimen surface opposite to that struck by the impactor is viewed by an infrared imaging device. Then, a sequence of thermal images is acquired during each impact test. Through the temperature variations experienced by the specimen surface, post-processing of such images supplies the likely occurred damage. In addition, specimens are non-destructively evaluated with lock-in thermography to visualize any manufacturing defects, as well as impact damage.

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

    International Nuclear Information System (INIS)

    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/cm2, 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.

  1. 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.

  2. Using bacterial bioluminescence to evaluate the impact of biofilm on porous media hydraulic properties.

    Science.gov (United States)

    Bozorg, Ali; Gates, Ian D; Sen, Arindom

    2015-02-01

    Biofilm formation in natural and engineered porous systems can significantly impact hydrodynamics by reducing porosity and permeability. To better understand and characterize how biofilms influence hydrodynamic properties in porous systems, the genetically engineered bioluminescent bacterial strain Pseudomonas fluorescens HK44 was used to quantify microbial population characteristics and biofilm properties in a translucent porous medium. Power law relationships were found to exist between bacterial bioluminescence and cell density, fraction of void space occupied by biofilm (i.e. biofilm saturation), and hydraulic conductivity. The simultaneous evaluation of biofilm saturation and porous medium hydraulic conductivity in real time using a non-destructive approach enabled the construction of relative hydraulic conductivity curves. Such information can facilitate simulation studies related to biological activity in porous structures, and support the development of new models to describe the dynamic behavior of biofilm and fluid flow in porous media. The bioluminescence based approach described here will allow for improved understanding and control of industrially relevant processes such as biofiltration and bioremediation. PMID:25479429

  3. 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.

  4. 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.

  5. Preliminary study on the development of EFB Fibre-sago starch composites: impact and flexural properties

    International Nuclear Information System (INIS)

    There is growing interest in the use of natural fibres as the reinforcements for polymer composites in the automotive industry and as matrix for composites in building products application to replace synthetic fibres. In this respect the aim of this study is to develop an environmental friendly composites for furniture industry based on EFB fibres and sago starch. In this preliminary study, a basic composition and processing of EFB fibres-sago starch composites were established and the properties of the composites were determined. EFB fibre content was varied between 50-80% by weight. The amount of sago starch in liquid form was also varied and final weight percentage of sago starch added into the EFB fibres was adjusted accordingly. The mixtures of EFB fibres and sago starch were blended using Haake Rheomixer. The preliminary results indicate that the impact and flexural strengths increased up to 33.58 J/m2 and 18.92 Mpa, respectively at 70% fibres contents. Further study is now being conducted to improve the processability of the composites by adding plasticisers and processing aids and to incorporate certain reactive additives that can enhance electron beam cross linking for further improvement on the mechanical properties of the composites. (Author)

  6. Study of welding velocity and pulse frequency on microstructure and mechanical properties of pulsed gas metal arc welded high strength low alloy steel

    International Nuclear Information System (INIS)

    Highlights: • Effect of welding velocity and pulse frequency in GMAW of HSLA steel. • Dependency of weldment microstructure on the welding velocity and pulse. • Reduction of hardness in the weld zone and HAZ with increasing of heat input. • The higher strength due to the higher amount of martensite. • Deterioration of impact properties with formation of grain boundary ferrite. - Abstract: The microstructure analysis and mechanical properties evaluation of pulsed gas metal arc and conventional gas metal arc welded high strength low alloy (HSLA) steel joints were investigated. Welding was carried out at welding velocity of 10 and 15 cm/min and pulse frequency of 50 and 100 Hz. The joints were subjected to optical microscope, scanning electron microscope, hardness, tensile test and Charpy impact toughness testing. Results showed that at high welding velocity the microstructure of the weld metal consisted mainly of acicular ferrite and lath martensite. At low welding velocity, small amounts of allotriomorphic and Widmanstatten ferrite were also observed. Results also showed that good mechanical properties can be obtained through the pulsed gas metal arc welding with welding velocity of 15 cm/min and pulse frequency of 50 Hz. Furthermore, with decreasing of welding velocity and increasing of the pulse frequency, impact energy decreased. This can be attributed to the formation of grain boundary ferrite and higher volume fraction of inclusion in weld metal. Results of fractography showed ductile fracture as a result of the equiaxed microvoids

  7. Process Integrated Heat Treatment of a Microalloyed Medium Carbon Steel: Microstructure and Mechanical Properties

    Science.gov (United States)

    Herbst, Sebastian; Schledorn, Mareike; Maier, Hans Jürgen; Milenin, Andrij; Nürnberger, Florian

    2016-04-01

    Air-water spray cooling was employed during a heat treatment to enhance the mechanical properties of microalloyed medium carbon steel test cylinders (38MnVS6, 88 mm diameter). Using appropriate cooling times and intensities, the test cylinders' surfaces could be quenched and subsequently self-tempered by the residual heat of the core. Simultaneously, it was possible to keep the core regions of the cylinders in the bainitic regime and carry out a quasi-isothermal holding. The resulting microstructures consisted of tempered martensite (near-surface) and bainite with pearlite and ferrite (core). Compared to the standard heat treatment (controlled air cooling), the tensile properties (proof stress and ultimate tensile strength) could be improved for both near-surface and core regions with the adapted spray cooling. A hardness profile with 450 HV10 surface hardness and a hardening depth of more than 11 mm could be realized. In addition, an increase of the impact toughness for the core was achieved, resulting in approximately 25 J charpy impact energy. This is a substantial improvement compared to standard heat treatment procedure and values reported in the literature and can be attributed to the reduced pearlite volume fraction and the increased amount of fine bainite.

  8. Effect of Clay Addition on Mechanical Properties of Unsaturated Polyester/Glass Fiber Composites

    Directory of Open Access Journals (Sweden)

    Kusmono

    2013-01-01

    Full Text Available Unsaturated polyester (UP/glass fiber/clay composites were prepared by hand layup method. The effect of clay loading on the morphological and mechanical properties of UP/glass fiber composites was investigated in this study. X-ray diffraction (XRD was used to characterize the structure of the composites. The mechanical properties of the composites were determined by tensile, flexural, unnotched Charpy impact and fracture toughness tests. XRD results indicated that the exfoliated structure was found in the composite containing 2 wt% of clay while the intercalated structure was obtained in the composite with 6 wt% of clay. The tensile strength, flexural strength, and flexural modulus of the composites were increased in the presence of clay. The optimum loading of clay in the UP/glass fiber composites was attained at 2 wt%, where the improvement in in tensile strength, flexural strength, and flexural modulus was approximately 13, 21, and 11%, respectively. On the other hand, the highest values in impact toughness and fracture toughness were observed in the composites with 4 wt% of clay.

  9. Tensile and impact behaviour of a microalloyed medium carbon steel: Effect of the cooling condition and corresponding microstructure

    International Nuclear Information System (INIS)

    Highlights: ► Effect of different cooling rate after hot rolling in medium C microalloyed steels. ► Effect of microstructure on the impact toughness, at room and sub-zero temperatures. ► Brittle behavior induced by the fracture of large (Ti, V)(C, N) inclusions. ► Acicular ferrite deflects propagation cracks increasing impact toughness. -- Abstract: The effect of cooling rate after hot rolling on the final microstructure and mechanical properties of a microalloyed medium C steel was investigated. The microstructure was characterized by optical microscopy; the mechanical behavior was studied by hardness, tensile and instrumented Charpy V-notch impact tests carried out at room and sub-zero temperatures. The results of microstructural analysis indicate that a low cooling rate of 0.7 °C/s led to a mixed microstructure consisting of perlite, pro-eutectoid ferrite and bainite, while an increase of the cooling rate to 7.5 °C/s favored the formation of martensite and acicular ferrite. This latter microstructure, in turn, induced an increase in the tensile strength of the steel, with a reduction of its elongation to failure, and superior impact toughness. Analyses of the fracture surfaces with scanning electron microscopy confirmed the influence of the two microstructures on the failure mechanisms of the steel.

  10. Impact of cementitious materials decalcification on transfer properties: application to radioactive waste deep repository

    International Nuclear Information System (INIS)

    Cementitious materials have been selected to compose the engineering barrier system (EBS) of the French radioactive waste deep repository, because of concrete physico-chemical properties: the hydrates of the cementitious matrix and the pH of the pore solution contribute to radionuclides retention; furthermore the compactness of these materials limits elements transport. The confinement capacity of the system has to be assessed while a period at least equivalent to waste activity (up to 100.000 years). His durability was sustained by the evolution of transfer properties in accordance with cementitious materials decalcification, alteration that expresses structure long-term behavior. Then, two degradation modes were carried out, taking into account the different physical and chemical solicitations imposed by the host formation. The first mode, a static one, was an accelerated decalcification test using nitrate ammonium solution. It replicates the EBS alteration dues to underground water. Degradation kinetic was estimated by the amount of calcium leached and the measurement of the calcium hydroxide dissolution front. To evaluate the decalcification impact, samples were characterized before and after degradation in term of microstructure (porosity, pores size distribution) and of transfer properties (diffusivity, gas and water permeability). The influence of cement nature (ordinary Portland cement, blended cement) and aggregates type (lime or siliceous) was observed: experiments were repeated on different mortars mixes. On this occasion, an essential reflection on this test metrology was led. The second mode, a dynamical degradation, was performed with an environmental permeameter. It recreates the EBS solicitations ensured during the re-saturation period, distinguished by the hydraulic pressure imposed by the geologic layer and the waste exothermicity. This apparatus, based on triaxial cell functioning, allows applying on samples pressure drop between 2 and 10 MPa and

  11. Prediction of quenched and tempered steel and cast steel properties

    OpenAIRE

    B. Smoljan; D. Iljkić; H. Novak

    2011-01-01

    Purpose: The influence of processing parameters, such as pouring temperature and cooling rate during the casting, as well as application of hot working and pre-heat treatment, on strength and toughness of quenched and tempered steel was investigated.Design/methodology/approach: Strength and toughness were presented by yield strength and Charpy-V notch toughness, respectively. Experimental procedure of material properties optimization was done using the 25-2 factor experiment.Findings: It was ...

  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. 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.

  14. Degradation of impact fracture during accelerated aging of weld metal on microalloyed steel

    International Nuclear Information System (INIS)

    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

  15. 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.

  16. Effect of post-weld aging treatment on mechanical properties of Tungsten Inert Gas welded low thickness 7075 aluminium alloy joints

    International Nuclear Information System (INIS)

    Highlights: → The effects of post-weld aging treatment on the properties of joints is studied. → The post-weld aging treatment increases the tensile strength of TIG welded joints. → The strengthening is due to a balance of dissolution, reversion and precipitation. → Simple post-weld aging at 140 oC enhances the properties of the welded joints. -- Abstract: This paper reports the influence of post-weld aging treatment on the microstructure, tensile strength, hardness and Charpy impact energy of weld joints low thickness 7075 T6 aluminium alloy welded by Tungsten Inert Gas (TIG). Hot cracking occurs in aluminium welds when high levels of thermal stress and solidification shrinkage are present while the weld is undergoing various degrees of solidification. Weld fusion zones typically exhibit microstructure modifications because of the thermal conditions during weld metal solidification. This often results in low weld mechanical properties and low resistance to hot cracking. It has been observed that the mechanical properties are very sensitive to microstructure of weld metal. Simple post-weld aging treatment at 140 oC applied to the joints is found to be beneficial to enhance the mechanical properties of the welded joints. Correlations between microstructures and mechanical properties were discussed.

  17. Effect of Boron on Microstructure and Mechanical Properties of Hot-Rolled Nb-ADDED Hsla H-Section Steel

    Science.gov (United States)

    Wang, Zuocheng; Cui, Guotao; Sun, Tao; Guo, Weimin; Zhao, Xiuling; Gao, Junqing; Dong, Changxing

    In our research, boron was added into the Nb-added high strength low alloy (HSLA) H-section steels. The contents of boron added were 4ppm, 8ppm and 11ppm, respectively. The mechanical properties of H-section steels with/without boron were examined by using uniaxial tensile test and Charpy impact test (V-notch). The morphologies of the microstructure and the fracture surfaces of the impact specimens were observed by metalloscope, stereomicroscope and electron probe. The experimental results indicate that boron gives a significant increase in impact toughness, especially in low temperature impact toughness, though it leads to an unremarkable increase in strength and plasticity. For instance, the absorbed energy at -40°C reaches up to 126J from 15J by 8ppm boron addition, and the ductile-brittle transition temperature declines by 20°C. It is shown that boron has a beneficial effect on grain refinement. The fracture mechanism is transited from cleavage fracture to dimple fracture due to boron addition.

  18. Impact of roots, mycorrhizas and earthworms on soil physical properties as assessed by shrinkage analysis

    Science.gov (United States)

    Milleret, R.; Le Bayon, R.-C.; Lamy, F.; Gobat, J.-M.; Boivin, P.

    2009-07-01

    SummarySoil biota such as earthworms, arbuscular mycorrhizal fungi (AMF) and plant roots are known to play a major role in engineering the belowground part of the terrestrial ecosystems, thus strongly influencing the water budget and quality on earth. However, the effect of soil organisms and their interactions on the numerous soil physical properties to be considered are still poorly understood. Shrinkage analysis allows quantifying a large spectrum of soil properties in a single experiment, with small standard errors. The objectives of the present study were, therefore, to assess the ability of the method to quantify changes in soil properties as induced by single or combined effects of leek roots ( Allium porrum), AMF ( Glomus intraradices) and earthworms ( Allolobophora chlorotica). The study was performed on homogenised soil microcosms and the experiments lasted 35 weeks. The volume of the root network and the external fungal hyphae was measured at the end, and undisturbed soil cores were collected. Shrinkage analysis allowed calculating the changes in soil hydro-structural stability, soil plasma and structural pore volumes, soil bulk density and plant available water, and structural pore size distributions. Data analysis revealed different impacts of the experimented soil biota on the soil physical properties. At any water content, the presence of A. chlorotica resulted in a decrease of the specific bulk volume and the hydro-structural stability around 25%, and in a significant increase in the bulk soil density. These changes went with a decrease of the structural pore volumes at any pore size, a disappearing of the thinnest structural pores, a decrease in plant available water, and a hardening of the plasma. On the contrary, leek roots decreased the bulk soil density up to 1.23 g cm -3 despite an initial bulk density of 1.15 g cm -3. This increase in volume was accompanied with a enhanced hydro-structural stability, a larger structural pore volume at any

  19. 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.

  20. Optimal Weld Parameters, Weld Microstructure, Mechanical Properties, and Hydrogen Absorption: An Effective Analysis

    Science.gov (United States)

    Bhattacharya, J.; Pal, T. K.

    2011-10-01

    Weld bead-in-grooves were deposited on low alloy, high strength steel plates (ASTM A 517 Grade "F") with a commercial flux-cored filler wire, Auto-MIG 420, at different welding conditions. Microstructure and mechanical properties of welds were characterized by means of optical microscopy, SEM, TEM, EPMA, microhardness measurements, tensile tests, and Charpy impact tests. Hydrogen content of weld metals in as-weld condition and after exposing in simulated service condition was measured by LECO Gas Analyzer. Microstructure of weld metals consisted primarily of lath martensite with small amount of M-A constituents (Martensite-Austenite alternating layers). For some particular welding conditions, such as higher heat input and lower preheat temperatures etc., acicular ferrite is observed with lath martensite. Welds consisting of acicular ferrite in the microstructure showed improved mechanical properties as well as lower hydrogen absorption. The study provides guidelines for selecting proper welding conditions, which results in lower propensity to absorb hydrogen during service, as well as better mechanical properties. Necessity of post-weld heat treatment processes, which is mainly performed to achieve toughness, may be reduced; consequently saving cost and time of the welding process.

  1. Standard test methods for notched bar impact testing of metallic materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 These test methods describe notched-bar impact testing of metallic materials by the Charpy (simple-beam) test and the Izod (cantilever-beam) test. They give the requirements for: test specimens, test procedures, test reports, test machines (see Annex A1) verifying Charpy impact machines (see Annex A2), optional test specimen configurations (see Annex A3), precracking Charpy V-notch specimens (see Annex A4), designation of test specimen orientation (see Annex A5), and determining the percent of shear fracture on the surface of broken impact specimens (see Annex A6). In addition, information is provided on the significance of notched-bar impact testing (see Appendix X2), methods of measuring the center of strike (see Appendix X2). 1.2 These test methods do not address the problems associated with impact testing at temperatures below -196 C (-320 F, 77 K). 1.3 The values stated in SI units are to be regarded as the standard. Inch-pound units are provided for information only. This standard does not purpor...

  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 chemically amended pig slurry on greenhouse gas emissions, soil properties and leachate.

    Science.gov (United States)

    O' Flynn, Cornelius J; Healy, Mark G; Lanigan, Gary J; Troy, Shane M; Somers, Cathal; Fenton, Owen

    2013-10-15

    The effectiveness of chemical amendment of pig slurry to ameliorate phosphorus (P) losses in runoff is well studied, but research mainly has concentrated only on the runoff pathway. The aims of this study were to investigate changes to leachate nutrient losses, soil properties and greenhouse gas (GHG) emissions due to the chemical amendment of pig slurry spread at 19 kg total phosphorus (TP), 90 kg total nitrogen (TN), and 180 kg total carbon (TC) ha(-1). The amendments examined were: (1) commercial grade liquid alum (8% Al2O3) applied at a rate of 0.88:1 [Al:TP], (2) commercial-grade liquid ferric chloride (38% FeCl3) applied at a rate of 0.89:1 [Fe:TP] and (3) commercial-grade liquid poly-aluminium chloride (PAC) (10% Al2O3) applied at a rate of 0.72:1 [Al:TP]. Columns filled with sieved soil were incubated for 8 mo at 10 °C and were leached with 160 mL (19 mm) distilled water wk(-1). All amendments reduced the Morgan's phosphorus and water extractable P content of the soil to that of the soil-only treatment, indicating that they have the ability to reduce P loss in leachate following slurry application. There were no significant differences between treatments for nitrogen (N) or carbon (C) in leachate or soil, indicating no deleterious impact on reactive N emissions or soil C cycling. Chemical amendment posed no significant change to GHG emissions from pig slurry, and in the cases of alum and PAC, reduced cumulative N2O and CO2 losses. Chemical amendment of land applied pig slurry can reduce P in runoff without any negative impact on nutrient leaching and GHG emissions. Future work must be conducted to ascertain if more significant reductions in GHG emissions are possible with chemical amendments. PMID:23850764

  4. Martian subsurface properties and crater formation processes inferred from fresh impact crater geometries

    Science.gov (United States)

    Stewart, Sarah T.; Valiant, Gregory J.

    2006-10-01

    The geometry of simple impact craters reflects the properties of the target materials, and the diverse range of fluidized morphologies observed in Martian ejecta blankets are controlled by the near-surface composition and the climate at the time of impact. Using the Mars Orbiter Laser Altimeter (MOLA) data set, quantitative information about the strength of the upper crust and the dynamics of Martian ejecta blankets may be derived from crater geometry measurements. Here, we present the results from geometrical measurements of fresh craters 3-50 km in rim diameter in selected highland (Lunae and Solis Plana) and lowland (Acidalia, Isidis, and Utopia Planitiae) terrains. We find large, resolved differences between the geometrical properties of the freshest highland and lowland craters. Simple lowland craters are 1.5-2.0 times deeper (≥5σo difference) with >50% larger cavities (≥2σo) compared to highland craters of the same diameter. Rim heights and the volume of material above the preimpact surface are slightly greater in the lowlands over most of the size range studied. The different shapes of simple highland and lowland craters indicate that the upper ˜6.5 km of the lowland study regions are significantly stronger than the upper crust of the highland plateaus. Lowland craters collapse to final volumes of 45-70% of their transient cavity volumes, while highland craters preserve only 25-50%. The effective yield strength of the upper crust in the lowland regions falls in the range of competent rock, approximately 9-12 MPa, and the highland plateaus may be weaker by a factor of 2 or more, consistent with heavily fractured Noachian layered deposits. The measured volumes of continuous ejecta blankets and uplifted surface materials exceed the predictions from standard crater scaling relationships and Maxwell's Z model of crater excavation by a factor of 3. The excess volume of fluidized ejecta blankets on Mars cannot be explained by concentration of ejecta through

  5. Aircraft Measurements of Saharan dust properties and impact of atmospheric transport during Fennec

    Science.gov (United States)

    Ryder, Claire; Highwood, Ellie; Rosenberg, Phil; Trembath, Jamie; Brooke, Jennifer; Bart, Mark; Dean, Angela; Dorsey, James; Crosier, Jonny; McQuaid, Jim; Brindley, Helen; Banks, James; Marsham, John; Sodemann, Harald; Washington, Richard

    2013-04-01

    Measurements of Saharan dust from recent airborne campaigns have found variations in size distributions and optical properties across Saharan and sub-Saharan Africa. These variations have an impact on radiation and thus weather and climate, and are important to characterise and understand, in particular, to understand how they vary with time after dust uplift, transport, and height in the atmosphere. New in-situ aircraft measurements from the Fennec 2011 aircraft campaign over a remote part of the Sahara Desert and the Atlantic Ocean will be presented and compared to previous airborne measurements. Size distributions extending to 300 μm will be shown, representing measurements extending further into the coarse mode than previously published for Saharan dust. The dust sampled by the aircraft covered a wide variety of loadings, dust source regions (Mali, Mauritania and Algeria) and dust ages (from fresh uplift to several days old). A significant coarse mode was present in the size distribution measurements with effective diameter up to 23 μm, and the mean size distribution showed greater concentrations of coarse mode than previous aircraft measurements. Single scattering albedo (SSA) values at 550nm calculated from these size distributions revealed high absorption from 0.77 to 0.95, with a mean of 0.85. Directly measured SSA values were higher (0.91 to 0.99) but new instrumentation revealed that these direct measurements, behind Rosemount inlets, overestimate the SSA by 0.02 to 0.20 depending on the concentration of coarse particles present. This is caused by inlet inefficiencies and pipe losses. Previous measurements of SSA from aircraft measurements may also have been overestimates for this reason. This has a significant impact on atmospheric heating rates. The largest dust particles were encountered closest to the ground, and were most abundant in cases where dust was freshly uplifted. Number concentration, mass loading and extinction coefficient showed inverse

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. 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...

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

    International Nuclear Information System (INIS)

    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

  12. Dynamic Properties of RHA Steel under Planar Shock Loading using Explosive Driven Plate Impact System

    Directory of Open Access Journals (Sweden)

    B. Venkataramudu

    2015-05-01

    Full Text Available Planar shock loading of rolled homogeneous armour (RHA steel has been studied at high pressures in the range of 20-100 GPa using an explosive-driven plate impact system. Shock velocities and flyer velocities are measured using time of arrival pins embedded in the target at known depths. The shock equation of state of RHA steel has been determined. α → ε phase transition stress and hugoniot elastic limit (HEL of RHA steel have been determined through manganin gauge and found to be 12.2 ±0.6 GPa and 4.1 ± 0.2 GPa, respectively. The experimental stress of phase transition has been compared with the stress calculated using ThermoCalc software. The shock properties have been incorporated in the Autodyn simulation package and simulations were performed to determine flyer velocity, pressures and the results are compared with that of experiments.Defence Science Journal, Vol. 65, No. 3, May 2015, pp.196-202, DOI: http://dx.doi.org/10.14429/dsj.65.7952

  13. Impact of gamma sterilization upon strength properties of soft-tissue transplants

    International Nuclear Information System (INIS)

    The impact of sterilization upon the strength of soft-tissue transplants stored in the tissue bank at the N. I. Pirogov Institute for Emergency Medical Aid, namely: dura mater, xenopericardium, and umbilical cord is studied. The radiation dose used was 2.5 Mrad. Findings indicated that the mean deformation limit of dura mater remained unaltered following treatment by either deep freezing and lyophilization or by lyophilization with a subsequent gamma-sterilization. The mean tension limit (destructive force per unit surface area of specimen cross section) has, however, dropped substantially for dura mater treated with lyophilization combined with gamma sterilization. While enopericardium strength was unaffected when treated with the proteolytic enzyme alprim, it declined upon subsequent gamma sterilization. Strength properties of umbilical cord were but insignificantly diminished after gamma sterilization. Based on these findings, it is recommended to avoid additional gamma sterilization of lyophilized dura mater and enzyme-treated xenopericardium in cases when allowance for medical strain upon transplants is to be made. (A.B.)

  14. 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.

  15. 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.

  16. Deposition velocities and impact of physical properties on ozone removal for building materials

    Science.gov (United States)

    Lin, Chi-Chi; Hsu, Shu-Chen

    2015-01-01

    This study aims to estimate the ozone deposition velocities of eight commonly used building materials (BMs) which include calcium silicate board (CSB), green calcium silicate board (GCSB), mineral fiber ceiling (MFC), green mineral fiber ceiling (GMFC), gypsum board (GB), green gypsum board (GGB), wooden flooring (WF) and green wooden flooring (GWF). In addition, the impact of physical properties (specific surface area and total pore volume of BM) on ozone removal ability was also explored and discussed. Studies were conducted in a small-scale environmental stainless steel chamber. CSB and GCSB showed the highest ozone deposition velocities, while WF and GWF showed the lowest ozone deposition velocities among test BMs materials. All reaction probabilities were estimated to fall within the order of magnitude of 10-6. Green BMs showed lower reaction probabilities with ozone comparing with non-green BMs except for GGB. Consistent with the trends for deposition velocity, fleecy and porous materials exhibit higher reaction probabilities than smooth, non-porous surfaces. Specific surface area of BM is more closely related to ozone removal than total pore volume of BM with R2 of 0.93 vs. R2 of 0.84. Discussion of Thiele modulus for all test BMs indicates surface reactions are occurring quickly relative to internal diffusion and ozone removal is internal diffusion-limited.

  17. 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.

  18. Chemical precursor impact on the properties of Cu2ZnSnS4 absorber layer

    Science.gov (United States)

    Vashistha, Indu B.; Sharma, Mahesh C.; Sharma, S. K.

    2016-04-01

    In present work impact of different chemical precursor on the deposition of solar absorber layer Cu2ZnSnS4 (CZTS) were studied by Chemical Bath Deposition (CBD) method without using expensive vacuum facilities and followed by annealing. As compared to the other deposition methods, CBD method is interesting one because it is simple, reproducible, non-hazardous, cost effective and well suited for producing large-area thin films at low temperatures, although effect of precursors and concentration plays a vital role in the deposition. So, the central theme of this work is optimizing and controlling of chemical reactions for different chemical precursors. Further Effect of different chemical precursors i.e. sulphate and chloride is analyzed by structural, morphological, optical and electrical properties. The X-ray diffraction (XRD) of annealed CZTS thin film revealed that films were polycrystalline in nature with kestarite tetragonal crystal structure. The Atomic Force micrographs (AFM) images indicated total coverage compact film and as well as growth of crystals. The band gap of annealed CZTS films was found in the range of optimal band gap by absorption spectroscopy.

  19. Impacts of parameters adjustment of relativistic mean field model on neutron star properties

    International Nuclear Information System (INIS)

    Analysis of the parameters adjustment effects in isovector as well as in isoscalar sectors of effective field based relativistic mean field (E-RMF) model in the symmetric nuclear matter and neutron-rich matter properties has been performed. The impacts of the adjustment on slowly rotating neutron star are systematically investigated. It is found that the mass–radius relation obtained from adjusted parameter set G2** is compatible not only with neutron stars masses from 4U 0614+09 and 4U 1636-536, but also with the ones from thermal radiation measurement in RX J1856 and with the radius range of canonical neutron star of X7 in 47 Tuc, respectively. It is also found that the moment inertia of PSR J073-3039A and the strain amplitude of gravitational wave at the Earth's vicinity of PSR J0437-4715 as predicted by the E-RMF parameter sets used are in reasonable agreement with the extracted constraints of these observations from isospin diffusion data. (author)

  20. Modeling the impact of conservation agriculture on crop production and soil properties in Mediterranean climate

    Science.gov (United States)

    Moussadek, Rachid; Mrabet, Rachid; Dahan, Rachid; Laghrour, Malika; Lembiad, Ibtissam; ElMourid, Mohamed

    2015-04-01

    In Morocco, rainfed agriculture is practiced in the majority of agricultural land. However, the intensive land use coupled to the irregular rainfall constitutes a serious threat that affect country's food security. Conservation agriculture (CA) represents a promising alternative to produce more and sustainably. In fact, the direct seeding showed high yield in arid regions of Morocco but its extending to other more humid agro-ecological zones (rainfall > 350mm) remains scarce. In order to promote CA in Morocco, differents trials have been installed in central plateau of Morocco, to compare CA to conventional tillage (CT). The yields of the main practiced crops (wheat, lentil and checkpea) under CA and CT were analyzed and compared in the 3 soils types (Vertisol, Cambisol and Calcisol). Also, we studied the effect of CA on soil organic matter (SOM) and soil losses (SL) in the 3 different sites. The APSIM model was used to model the long term impact of CA compared to CT. The results obtained in this research have shown favorable effects of CA on crop production, SOM and soil erosion. Key words: Conservation agriculture, yield, soil properties, modeling, APSIM, Morocco.

  1. Impact of Organic and Conventional Systems of Coffee Farming on Soil Properties and Culturable Microbial Diversity.

    Science.gov (United States)

    Velmourougane, Kulandaivelu

    2016-01-01

    A study was undertaken with an objective of evaluating the long-term impacts of organic (ORG) and conventional (CON) methods of coffee farming on soil physical, chemical, biological, and microbial diversity. Electrical conductivity and bulk density were found to increase by 34% and 21%, respectively, in CON compared to ORG system, while water holding capacity was found decreased in both the systems. Significant increase in organic carbon was observed in ORG system. Major nutrients, nitrogen and potassium, levels showed inclination in both ORG and CON system, but the trend was much more pronounced in CON system. Phosphorus was found to increase in both ORG and CON system, but its availability was found to be more with CON system. In biological attributes, higher soil respiration and fluorescein diacetate activity were recorded in ORG system compared to CON system. Higher soil urease activity was observed in CON system, while dehydrogenase activity does not show significant differences between ORG and CON systems. ORG system was found to have higher macrofauna (31.4%), microbial population (34%), and microbial diversity indices compared to CON system. From the present study, it is accomplished that coffee soil under long-term ORG system has better soil properties compared to CON system. PMID:27042378

  2. Impact of Organic and Conventional Systems of Coffee Farming on Soil Properties and Culturable Microbial Diversity

    Science.gov (United States)

    2016-01-01

    A study was undertaken with an objective of evaluating the long-term impacts of organic (ORG) and conventional (CON) methods of coffee farming on soil physical, chemical, biological, and microbial diversity. Electrical conductivity and bulk density were found to increase by 34% and 21%, respectively, in CON compared to ORG system, while water holding capacity was found decreased in both the systems. Significant increase in organic carbon was observed in ORG system. Major nutrients, nitrogen and potassium, levels showed inclination in both ORG and CON system, but the trend was much more pronounced in CON system. Phosphorus was found to increase in both ORG and CON system, but its availability was found to be more with CON system. In biological attributes, higher soil respiration and fluorescein diacetate activity were recorded in ORG system compared to CON system. Higher soil urease activity was observed in CON system, while dehydrogenase activity does not show significant differences between ORG and CON systems. ORG system was found to have higher macrofauna (31.4%), microbial population (34%), and microbial diversity indices compared to CON system. From the present study, it is accomplished that coffee soil under long-term ORG system has better soil properties compared to CON system. PMID:27042378

  3. Salt content impact on the unsaturated property of bentonite-sand buffer backfilling materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Ming [Key Laboratory of Mechanics on Disaster and Environment in Western China, Lanzhou University, Lanzhou 730000 (China); Zhang Huyuan, E-mail: p1314lvp@yahoo.com.cn [Key Laboratory of Mechanics on Disaster and Environment in Western China, Lanzhou University, Lanzhou 730000 (China); Jia Lingyan; Cui Suli [Key Laboratory of Mechanics on Disaster and Environment in Western China, Lanzhou University, Lanzhou 730000 (China)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer SWCC and infiltration process of bentonite-sand mixtures is researched. Black-Right-Pointing-Pointer The k{sub u} of bentonite-sand mixtures was evaluated as the buffer backfilling materials. Black-Right-Pointing-Pointer Salt content impacting on the unsaturated property of bentonite-sand materials is small. - Abstract: Bentonite mixed with sand is often considered as possible engineered barrier in deep high-level radioactive waste disposal in China. In the present work, the vapor transfer technique and water infiltration apparatus were used to measure the soil water characteristic curve (SWCC) and unsaturated hydraulic conductivity (k{sub u}) of bentonite-sand mixtures (B/S) effected by salt content. Results show, the water-holding capacity and k{sub u} increase slightly with the concentration of Na{sup +} in pore liquid increasing from 0 g/L to 12 g/L, similar with the solution concentration of Beishan groundwater in China. Salt content in the laboratory produced only one order of magnitude increase in k{sub u}, which is the 'safe' value. The different pore liquid concentrations used in this study led to small differences in thickness of diffuse double layer of bentonite in mixtures, this might explain why some differences have been found in final values of k{sub u}.

  4. 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; Z

    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.

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

    Science.gov (United States)

    Hallquist, M.; Wenger, J. C.; Baltensperger, U.; Rudich, Y.; Simpson, D.; Claeys, M.; Dommen, J.; Donahue, N. M.; George, C.; Goldstein, A. H.; Hamilton, J. F.; Herrmann, H.; Hoffmann, T.; Iinuma, Y.; Jang, M.; Jenkin, M. E.; Jimenez, J. L.; Kiendler-Scharr, A.; Maenhaut, W.; McFiggans, G.; Mentel, Th. F.; Monod, A.; Prévôt, A. S. H.; Seinfeld, J. H.; Surratt, J. D.; Szmigielski, R.; Wildt, J.

    2009-07-01

    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.

  6. 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

  7. Multi-scales modeling of reactive transport mechanisms. Impact on petrophysical properties during CO2 storage

    International Nuclear Information System (INIS)

    The geo-sequestration of carbon dioxide (CO2) is an attractive option to reduce the emission of greenhouse gases. Within carbonate reservoirs, acidification of brine in place can occur during CO2 injection. This acidification leads to mineral dissolution which can modify the transport properties of a solute in porous media. The aim of this study is to quantify the impact of reactive transport on a solute distribution and on the structural modification induced by the reaction from the pore to the reservoir scale. This study is focused on reactive transport problem in the case of single phase flow in the limit of long time. To do so, we used a multi-scale up-scaling method that takes into account (i) the local scale, where flow, reaction and transport are known; (ii) the pore scale, where the reactive transport is addressed by using averaged formulation of the local equations; (iii) the Darcy scale (also called core scale), where the structure of the rock is taken into account by using a three-dimensions network of pore-bodies connected by pore-throats; and (iv) the reservoir scale, where physical phenomenon, within each cell of the reservoir model, are taken into account by introducing macroscopic coefficients deduced from the study of these phenomenon at the Darcy scale, such as the permeability, the apparent reaction rate, the solute apparent velocity and dispersion. (author)

  8. Erosion of POSS-polyimide films under hypervelocity impact and atomic oxygen: The role of mechanical properties at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Verker, R. [Space Environment Group, Soreq NRC, Yavne 81800 (Israel); School of Mechanical Engineering, Tel-Aviv University, Ramat Aviv, Tel-Aviv 69978 (Israel)], E-mail: rverker@soreq.gov.il; Grossman, E. [Space Environment Group, Soreq NRC, Yavne 81800 (Israel); Eliaz, N. [School of Mechanical Engineering, Tel-Aviv University, Ramat Aviv, Tel-Aviv 69978 (Israel)

    2009-02-15

    Low Earth orbital debris impacts on the external surfaces of satellites have increased dramatically in recent years. Polyimides are used as the outer layer of thermal control insulation blankets, covering most of the external spacecraft surfaces that are exposed to the space environment. A recently developed material, named polyhedral oligomeric silsesquioxane (POSS)-polyimide, shows significant enhancement in withstanding the space environment. In this work, the combined effect of ground-simulated hypervelocity space debris impacts and atomic oxygen (AO) on the erosion of POSS-containing polyimide films was investigated. During such hypervelocity impacts, elevated temperatures, on the order of hundreds degrees, are formed. A laser-driven flyer system was used to accelerate aluminum flyers to impact velocities of up to 3 km s{sup -1}. The impacted films were exposed to an oxygen RF plasma environment, simulating the effect of AO in the low Earth orbit. Impacted polyimide films exposed to AO revealed synergistic erosion effect, while impacted POSS-containing samples showed improved erosion resistance. The increased erosion rate of the impacted polyimide film is explained by formation of residual stresses that affect the oxidation mainly by increasing the diffusivity of oxygen into the subsurface layers. Mechanical properties of the POSS-containing samples performed at 450 deg. C and fractographic examination supports the above hypothesis.

  9. 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.

  10. 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

  11. Experimental Techniques for Evaluating the Effects of Aging on Impact and High Strain Rate Properties of Triaxial Braided Composite Materials

    Science.gov (United States)

    Pereira, J. Michael; Roberts, Gary D.; Ruggeri, Charles R.; Gilat, Amos; Matrka, Thomas

    2010-01-01

    An experimental program is underway to measure the impact and high strain rate properties of triaxial braided composite materials and to quantify any degradation in properties as a result of thermal and hygroscopic aging typically encountered during service. Impact tests are being conducted on flat panels using a projectile designed to induce high rate deformation similar to that experienced in a jet engine fan case during a fan blade-out event. The tests are being conducted on as-fabricated panels and panels subjected to various numbers of aging cycles. High strain rate properties are being measured using a unique Hopkinson bar apparatus that has a larger diameter than conventional Hopkinson bars. This larger diameter is needed to measure representative material properties because of the large unit cell size of the materials examined in this work. In this paper the experimental techniques used for impact and high strain rate testing are described and some preliminary results are presented for both as-fabricated and aged composites.

  12. Microstructure and Properties of SA533B Steel Plates for Nuclear Power Plant Equipments%核电设备用SA533B钢板的组织和性能

    Institute of Scientific and Technical Information of China (English)

    卢书媛; 顾伟; 许玉宇; 王卫忠; 钱伟; 徐海斌

    2011-01-01

    对核电设备用SA533B钢板的显微组织、拉伸性能、冲击性能以及中温疲劳性能进行了分析.结果表明:SA533B钢板的显微组织为晶粒均匀细小的粒状贝氏体,为正常的调质组织;该钢板的综合力学性能优良,同时具有高的强度、塑性、冲击韧度及疲劳性能,满足核级安全性能的要求.%The microstructure, tensile properties, Charpy impact properties and fatigue behavior at 350 ℃ of SA533B steel plates for nuclear power plant equipments were analyzed.The results show that the microstructure of SA533B steel plates was fine and homogeneous granular bainite, and was normal quenched and tempered microstructure.The steel plates had excellent general mechanical properties, bad high strength, plasticity, impact toughness and fatigue properties at the same time, and conformed to the requirements for reactor design.

  13. Long-term aging of cast stainless steels: Mechanisms and resulting properties

    International Nuclear Information System (INIS)

    Mechanical property data are presented from Charpy-impact, tensile, and J-R curve tests for several heats of cast stainless steel aged up to 10,000 h at 450, 400, 350, 320 and 290 deg. C. The results indicate that thermal aging increases the tensile strength and decreases the impact energy, JIC, and tearing modules of the steels. Also, the ductile-to-brittle transition curve shifts to higher temperatures. The ferrite content and concentration of carbon in the steel have a strong effect on the overall process of low-temperature embrittlement. The low-carbon CF-3 steels are the most resistant and the molybdenum-containing high-carbon CF-8M steels are the most susceptible to low-temperature embrittlement. Microstructural data indicate that three processes contribute to embrittlement of cast stainless steels, viz., Cr-rich α' and G-phase precipitation in the ferrite, and carbide precipitation on the austenite/ferrite phase boundary. The influence of nitrogen content and ferrite distribution on loss of toughness are discussed. The data also indicate that existing correlations do not accurately represent the embrittlement behavior over the temperature range 280-450 deg. C, i.e., extrapolation of high temperature data to reactor temperatures may not be valid for some compositions of cast stainless steel. (author)

  14. 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.

  15. Relation among rolling parameters, microstructures and mechanical properties in an acicular ferrite pipeline steel

    International Nuclear Information System (INIS)

    The correlation among thermo-mechanical controlled processing (TMCP) parameters, microstructures and mechanical properties of an acicular ferrite (AF) pipeline steel was investigated in this study. The steel was hot rolled by four different kinds of TMCP to obtain different AF microstructures, and the corresponding mechanical properties were analyzed. Electron backscatter diffraction (EBSD) analysis was conducted to determine the effective grain size (EGS) in the steel. It was found that the EGS in the steel reduced obviously with decrease of the finish rolling temperature (FRT), but little changed with the cooling rate (CR) and the simulated coiling temperature (SCT). Additionally, the fraction of low angle grain boundaries (LAGBs) increased with increasing CR in the experimental range. It was shown that yield strength of the steel was enhanced by the increased CR and SCT, and reduced FRT, which were corresponding with the increases of LAGB fraction and precipitated carbonitrides as well as the decrease of EGS, respectively. Charpy impact results showed that the low temperature toughness of the steel with FRT about 40 oC above Ar3 tended to be the best, which was in good accordance with the highest fraction of high angle grain boundaries (HAGBs), but seemed not to be related with the EGS.

  16. Effects of Ultra Fast Cooling on Microstructure and Mechanical Properties of Pipeline Steels

    Science.gov (United States)

    Tian, Yong; Li, Qun; Wang, Zhao-dong; Wang, Guo-dong

    2015-09-01

    X70 (steel A) and X80 (steel B) pipeline steels were fabricated by ultra fast cooling (UFC). UFC processing improves not only ultimate tensile strength (UTS), yield strength (YS), yield ratio (YS/UTS), and total elongation of both steels, but also their Charpy absorbed energy ( A K) as well. The microstructures of both steels were all composed of quasi polygonal, acicular ferrite (AF), and granular bainite. MA islands (the mixtures of brittle martensite and residual austenite) are more finely dispersed in steel B, and the amount of AF in steel B is much more than that in steel A. The strength of steel B is higher than that of steel A. This is mainly attributed to the effect of the ferrite grain refinement which is resulted from UFC processing. The finely dispersed MA islands not only provide dispersion strengthening, but also reduce loss of impact properties to pipeline steels. UFC produces low-temperature transformation microstructures containing larger amounts of AFs. The presence of AF is a crucial factor in achieving desired mechanical properties for both steels. It is suggested that the toughness of the experimental steel increases with increasing the amount of AF.

  17. Joints Properties of One Side Welded of Ship Materials with Variation of Angle Groove

    Directory of Open Access Journals (Sweden)

    Yustiasih Purwaningrum & b Isharyadi

    2015-05-01

    Full Text Available Indonesian National Transportation Safety Commission based on data from the period 2003-2008 and The Study for the Maritime Traffic Safety System Development Plan states that 21% of the cause of the accident was the failure of Indonesian ship in the structure of the ship (hull structure. This study aimed to investigate the effect of variations in the angle groove of one side welding. Material used is low carbon steel LR grade A in a thickness 12 mm were welded using GMAW (Gas Metal Arc Welding with a angle groove 20°, 40° and 60°. The physical properties examined with an optical microscope and measured mechanical properties with regard to strength, hardness, and tougness using tensile test, hardness test and impact test Charpy Vickers respectively. The test results show the microstructure of the weld, HAZ, and base metals has the same structure is ferrite and perlite. From the results of mechanical tests showed tensile strength is highest in the 40° angle groove is 338.9 MPa. The values of absorbed energy approximately 170 J, which was 58 % of that of weld raw materials.

  18. 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. PMID:23238108

  19. Effects of Ti addition and reheating quenching on grain refinement and mechanical properties in low carbon medium manganese martensitic steel

    International Nuclear Information System (INIS)

    Highlights: → TiC precipitation can induce the grain refinement after reheating-quenching process. → EGS refinement is more effective to explain the improvement of toughness. → The experimental results of precipitation agree with the theoretical calculations. → Excellent mechanical properties with high strength and high toughness can be gained. -- Abstract: The grain refinement and mechanical properties improvement resulted from Ti addition and reheating quenching were demonstrated in this study. The direct quenched medium manganese steel with low carbon content (0.05C) was treated by reheating quenching process. The yield strength and Charpy impact energy were measured. The microstructures and the second precipitated particles were examined by optical microscopy (OM), scanning electron microscopy (SEM), electron back-scattered diffraction (EBSD), transmission electron microscopy (TEM), X-rays diffraction and phase analysis method. It was found that reheating quenching at 900-1000 oC resulted in significant grain refinement, especially the refinement of effective grain size (EGS), which was attributed to the large amount nano-sized precipitation of TiC. In addition, high elastic modulus was also obtained from the large amount TiC precipitated from the matrix. It is concluded that reheating quenching process is a useful method to refine the grain size and improve the combined mechanical properties of the martensitic steel through Ti addition.

  20. The stress corrosion resistance and the cryogenic temperature mechanical properties of hot rolled Nitronic 32 bar material

    Science.gov (United States)

    Montano, J. W. L.

    1977-01-01

    The ambient and cryogenic temperature mechanical properties and the ambient temperature stress corrosion properties of hot rolled and centerless ground Nitronic 32 stainless steel bar material are presented. The mechanical properties of longitudinal specimens were evaluated at test temperatures from ambient to liquid hydrogen. The tensile test data indicated increasing smooth tensile strength with decreasing temperature to liquid hydrogen temperature. However, below -200 F (-129.0 C) the notched tensile strength decreased slightly and below -320 F (-196.0 C) the decrease was significant. The elongation and reduction of area decreased drastically at temperatures below -200 F (-129.0 C). The Charpy V-notched impact energy decreased steadily with decreasing test temperature. Stress corrosion tests were performed on longitudinal tensile specimens stressed to 0, 75, and 90 percent of the 0.2 percent yield strength and on transverse 'C'-ring specimens stressed to 75 and 90 percent of the yield strength and exposed to: alternate immersion in a 3.5 percent NaCl bath, humidity cabinet environment, and a 5 percent salt spray atmosphere. The longitudinal tensile specimens experienced no corrosive attack; however, the 'C'-rings exposed to the alternate immersion and to the salt spray experienced some shallow etching and pitting, respectively. Small cracks appeared in two of the 'C'-rings after one month exposure to the salt spray.

  1. Review of mechanical properties and microstructures of Types 304 and 316 stainless steel after long-term aging

    International Nuclear Information System (INIS)

    Because commercial liquid metal fast breeder reactors (LMFBRs) will be designed to last for 35 to 40 years, an understanding of the mechanical behavior of the structural alloys used is required for times of 2.2 to 2.5 x 105 h (assuming a 70% availability factor). Types 304 and 316 stainless steel are used extensively in LMFBR systems. These alloys are in a metastable state when installed and evolve to a more stable state and, therefore, microstructure during plant operation. Correlations of microstructures and mechanical properties during aging under representative LMFBR temperature and loading conditions is desirable from the standpoint of assuring safe, reliable, and economic plant operation. We reviewed the mechanical properties and microstructures of types 304 and 316 stainless steel wrought alloys, welds, and castings after long-term aging in air to 9 x 104 h (about 10-1/2 years). The principal effect of such aging is to reduce fracture toughness (as measured in Charpy impact tests) and tensile ductility. Examples are cited, however, where, because stable microstructures are achieved, these as well as strength-related properties can be expected to remain adequate for service life exposures. 27 figures

  2. Review of mechanical properties and microstructures of types 304 and 316 stainless steel after long-term aging

    International Nuclear Information System (INIS)

    Because commercial liquid metal fast breeder reactors (LMFBRs) will be designed to last for 35 to 40 years, an understanding of the mechanical behavior of the structural alloys used is required for times of 2.2 to 2.5x105h (assuming a 70% availability factor). Types 304 and 316 stainless steel are used extensively in LMFBR systems. These alloys are in a metastable state when installed and evolve to a more stable state and, therefore, microstructure during plant operation. Correlations of microstructures and mechanical properties during aging under representative LMFBR temperature and loading conditions is desirable from the standpoint of assuring safe, reliable, and economic plant operation. We reviewed the mechanical properties and microstructures of types 304 and 316 stainless steel wrought alloys, welds, and castings after long-term aging in air to 9x104h (about 10-1/2 years). The principal effect of such aging is to reduce fracture toughness (as measured in Charpy impact tests) and tensile ductility. Examples are cited, however, where, because stable microstructures are achieved, these as well as strength-related properties can be expected to remain adequate for service life exposures. (author)

  3. The stress corrosion resistance and the cryogenic temperature mechanical properties of hot-rolled Nitronic 32 bar material

    International Nuclear Information System (INIS)

    The ambient and cryogenic temperature mechanical properties and the ambient temperature stress corrosion properties of hot rolled and centerless ground Nitronic 32 stainless steel bar material are presented. The mechanical properties of longitudinal specimens were evaluated at test temperatures from ambient to liquid hydrogen. The tensile test data indicated increasing smooth tensile strength with decreasing temperature to liquid hydrogen temperature. However, below -200 F (-129.0 C) the notched tensile strength decreased slightly and below -320 F (-196.0 C) the decrease was significant. The elongation and reduction of area decreased drastically at temperatures below -200 F (-129.0 C). The Charpy V-notched impact energy decreased steadily with decreasing test temperature. Stress corrosion tests were performed on longitudinal tensile specimens stressed to 0, 75, and 90 percent of the 0.2 percent yield strength and on transverse 'C'-ring specimens stressed to 75 and 90 percent of the yield strength and exposed to alternate immersion in a 3.5 percent NaCl bath, humidity cabinet environment, and a 5 percent salt spray atmosphere. The longitudinal tensile specimens experienced no corrosive attack; however, the 'C'-rings exposed to the alternate immersion and to the salt spray experienced some shallow etching and pitting, respectively. Small cracks appeared in two of the 'C'-rings after one month exposure to the salt spray

  4. Effect of chromium, tungsten, tantalum, and boron on mechanical properties of 5-9Cr-WVTaB steels

    International Nuclear Information System (INIS)

    The Cr-W-V-Ta reduced-activation ferritic/martensitic steels use tungsten and tantalum as substitutes for molybdenum and niobium in the Cr-Mo-V-Nb steels that the reduced-activation steels replaced as candidate materials for fusion applications. Studies were made to determine the effect of W, Ta, and Cr composition on the tensile and Charpy properties of the Cr-W-V-Ta; steels with 5%, 7%, and 9% Cr with 2% or 3% W and 0%, 0.05%, or 0.10% Ta were examined. Boron has a long history of use in steels to improve properties, and the effect of boron was also examined. Regardless of the chromium concentration, the steels with 2% W and 0.05-0.1% Ta generally had a better combination of tensile and Charpy properties than steels with 3% W. Boron had a negative effect on properties for the 5% and 7% Cr steels, but had a positive effect on the 9% Cr steel. When the 5, 7, and 9Cr steels containing 2% W and 0.05% Ta were compared, the tensile and Charpy properties of the 5 and 9Cr steels were better than those of the 7Cr steel, and overall, the properties of the 5Cr steel were better than those of the 9Cr steel. Such information will be useful if the properties of the reduced-activation steels are to be optimized

  5. 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.

  6. Risky Business: The Impact of Property Rights on Investment and Revenue in the Film Industry

    OpenAIRE

    Kuppuswamy, Venkat; Baldwin, Carliss Young

    2012-01-01

    Our paper tests a key prediction of property rights theory, specifically, that agents will respond to marginal incentives embedded in property rights when making non-contractible, revenue-enhancing investments. (Grossman and Hart, 1986; Hart and Moore, 1990). Using rich project-level data from the U.S. film industry, we investigate variation in property right allocations, investment choices, and film revenues to test the distinctive aspects of property-rights theory. Empirical tests of these ...

  7. Influence of non-metal inclusions on mechanical properties of Clam steel

    International Nuclear Information System (INIS)

    Full text of publication follows: With good irradiation swelling resistance, thermo-physical and thermo-mechanical properties, the RAFMs (Reduced Activation Ferritic / Martensitic steels) have been considered as the primary candidate structural materials for application in fusion systems in the near future. The China Low Activation Martensitic steel (CLAM) based on the nominal compositions of 9Cr1.5WVTa is being developed in Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) under wide collaboration with many other institutes and universities in domestic and overseas. The heat treatment of CLAM is quenching at 980 deg. C for 30 minutes and then cooled by air or water and tempering at 760 deg. C for 90 minutes and then cooled by air. Mechanical properties of CLAM were strongly affected by the size and distribution of non-metal inclusions as most steels, and its effects on mechanical properties of CLAM steel has been investigated. The evaluation of the non-metallic inclusions in CLAM has been done by optical microscopy observation, electron microscopy observation and Energy Dispersive X-ray Spectroscopy (EDS) analysis. The results showed that most of the non-metal inclusions in CLAM were brittle alumina phase with large size and non-uniform distribution and those were no good to the mechanical properties of CLAM. So electroslag remelting process was chosen to remelt the ingot which was smelted previously by vacuum induction furnace. Inclusion detection by optical microscopy showed that both of the dimensions and quantity of the inclusions decreased and their distributions became more uniform compared with the case before. And the tensile tests and Charpy V-notch impact tests indicated that electroslag remelting improved the tensile properties and impact toughness of CLAM steel. (authors)

  8. 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.

  9. Effect of Ultrasonic Treatment on The Tensile and Impact Properties of Thermoplastic Natural Rubber Nanocomposites Reinforced with Carbon Nanotubes

    International Nuclear Information System (INIS)

    This study investigates the effect of ultrasonic treatment on the mechanical properties of thermoplastic natural rubber (TPNR) nanocomposites reinforced with multi-walled nanotubes. The TPNR nanocomposites were prepared using melt blending method from polypropylene (PP), natural rubber (NR) and liquid natural rubber (LNR) as a compatibilizer, respectively, with 1% of Multi-wall nanotubes. The nanocomposite was prepared using the indirect technique (IDT) with the optimum processing parameters at 180 deg. C with 80 rpm mixing speed and 11 minutes processing time. The results have showed that the good dispersion on nanotubes was achieved by ultrasonic treatment. The optimization of ultrasonic time indicated that the maximum tensile and impact properties occurred with 1 h ultrasonic treatment. The Young's modulus, tensile strength, elongation at break and impact strength have increased by almost 11%, 21%, 43% and 50%, respectively. The results from our study indicate that nanotubes have as excellent reinforcement filler in TPNR matrix.

  10. Effect of Ultrasonic Treatment on The Tensile and Impact Properties of Thermoplastic Natural Rubber Nanocomposites Reinforced with Carbon Nanotubes

    Science.gov (United States)

    Tarawneh, Mou'ad A.; Ahmad, Sahrim Hj.; Yahya, S. Y.; Rasid, Rozaidi

    2009-06-01

    This study investigates the effect of ultrasonic treatment on the mechanical properties of thermoplastic natural rubber (TPNR) nanocomposites reinforced with multi-walled nanotubes. The TPNR nanocomposites were prepared using melt blending method from polypropylene (PP), natural rubber (NR) and liquid natural rubber (LNR) as a compatibilizer, respectively, with 1% of Multi-wall nanotubes. The nanocomposite was prepared using the indirect technique (IDT) with the optimum processing parameters at 180° C with 80 rpm mixing speed and 11 minutes processing time. The results have showed that the good dispersion on nanotubes was achieved by ultrasonic treatment. The optimization of ultrasonic time indicated that the maximum tensile and impact properties occurred with 1 h ultrasonic treatment. The Young's modulus, tensile strength, elongation at break and impact strength have increased by almost 11%, 21%, 43% and 50%, respectively. The results from our study indicate that nanotubes have as excellent reinforcement filler in TPNR matrix.

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

    International Nuclear Information System (INIS)

    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

  12. Atomistic investigation on the structure-property relationship during thermal spray nanoparticle impact

    OpenAIRE

    Goel, Saurav; Faisal, Nadimul Haque; Ratia, Vilma; Agrawal, Anupam; Stukowski, Alexander

    2014-01-01

    During thermal spraying, hot particles impact on a colder substrate. This interaction of crystalline copper nanoparticles and copper substrate is modelled, using MD simulation. The quantitative results of the impacts at different velocities and temperatures are evaluated using a newly defined flattening aspect ratio. This ratio between the maximum diameter after the impact and the height of the splat increases with increasing Reynolds numbers until a critical value is reached. At higher Reyno...

  13. Fracture toughness correlation with microstructure and other mechanical properties in near-eutectoid steel

    OpenAIRE

    Sudhakar, KV; Murty, GS

    1998-01-01

    The variation of yield strength and fracture toughness was investigated for four different heat treatments attempted on specimens of a near-eutectoid steel. The aim of this study was to optimize the microstructure for simultaneous improvements in strength and toughness. Further, the fracture toughness deduced through empirical relations from tensile and charpy impact tests was compared with those measured directly according to ASTM Designation: E 399. Among the four different heat treatments ...

  14. Psychometric properties of the Children’s Revised Impact of Events Scale (CRIES) with Bangladeshi children and adolescents

    OpenAIRE

    Farah Deeba; Rapee, Ronald M; Tania Prvan

    2014-01-01

    Identification of possible cases suffering post-traumatic stress disorder (PTSD) is important, especially in developing countries where traumatic events are typically prevalent. The Children’s Revised Impact of Events Scale is a reliable and valid measure that has two brief versions (13 items and 8 items) to assess reactions to traumatic events among young people. The current study evaluated the psychometric properties of both versions of the CRIES in a sample of 1,342 children and adolescent...

  15. Bacterial ice nuclei impact cloud lifetime and radiative properties and reduce atmospheric heat loss in the BRAMS simulation model

    OpenAIRE

    Costa, Tassio S; Yamasoe, Marcia A; Martins, Jorge A.; Morris, Cindy E.

    2014-01-01

    This study examines the effect of the bacterial species Pseudomonas syringae acting as ice nuclei (IN) on cloud properties to understand its impact on local radiative budget and heating rates. These bacteria may become active IN at temperatures as warm as - 2 degrees C. Numerical simulations were developed using the Brazilian Regional Atmospheric Model System (BRAMS). To investigate the isolated effect of bacterial IN, four scenarios were created considering only homogeneous and bacterial ice...

  16. The Potential Impact of Biofield Energy Treatment on the Physical and Thermal Properties of Silver Oxide Powder

    OpenAIRE

    Trivedi, Mahendra Kumar

    2015-01-01

    Silver oxide has gained significant attention due to its antimicrobial activities. The purpose of this study was to evaluate the impact of biofield energy treatment on the physical and thermal properties of silver oxide (Ag2O). The silver oxide powder was divided into two parts, one part was kept as control and another part was received Mr. Trivedi’s biofield energy treatment. The control and treated samples were analyzed using X-ray diffraction (XRD), differential scanning calorimetry ...

  17. Soil chemicals properties and wheat genotype impact on micronutrient and toxic elements content in wheat integral flour

    OpenAIRE

    Krunoslav Karalić; Ante Nevistić; Brigita Popović; Zdenko Lončarić; Zorica Jurković; Meri Engler

    2012-01-01

    Aim To determine impact of soil chemical properties and different wheat genotypes in Croatia on micronutrient and toxic elements content in wheat integral flour. Methods Research was conducted and soil samples were collected from two different production areas in the Republic of Croatia: Ovčara and Dalj. Besides soil samples, grain samples of four different Croatian wheat genotypes were also collected and analyzed. In total, 40 samples of soil and 40 samples of wheat grain were analysed for t...

  18. Impacts of the Manaus pollution plume on the microphysical properties of Amazonian warm-phase clouds in the wet season

    OpenAIRE

    Cecchini, Micael A.; Machado, Luiz A. T.; Comstock, Jennifer M.; Mei, Fan; Wang, Jian; Fan, Jiwen; Tomlinson, Jason M.; Schmid, Beat; Albrecht, Rachel; Martin, Scot T.; Artaxo, Paulo

    2016-01-01

    The remote atmosphere over the Amazon can be similar to oceanic regions in terms of aerosol conditions and cloud type formations. This is especially true during the wet season. The main aerosol-related disturbances over the Amazon have both natural sources, such as dust transport from Africa, and anthropogenic sources, such as biomass burning or urban pollution. The present work considers the impacts of the latter on the microphysical properties of warm-phase clouds by analy...

  19. The Impact of Solar Panels on the Price and Saleability of Domestic Properties in Oxford

    Directory of Open Access Journals (Sweden)

    Charlie Morris-Marsham

    2011-09-01

    Full Text Available Studies into energy efficiency and micro-generation in the built environment tend to focus on the economic or environmental paybacks of installed technologies. However, as the opening quote suggests, features that reduce the energy consumption of a property may also play a role in influencing property value. To date research into whether and to what extent energy efficiency and micro-generation technologies, such as solar panels, affect the price and saleability of properties has been limited and the assumption amongst property professionals has been that these installations do not affect the price or saleability of properties (Home Sale Network 2009; RICS 2010. This paper addresses the topic by reporting the results of a study which examined property buyer responses to solar panels and explored the expectations of householders and estate agents surrounding solar panels and value in domestic properties in Oxford.

  20. Effect of RE Modification and Heat Treatment on Impact Fatigue Property of a Wear Resistant White Cast Iron

    Institute of Scientific and Technical Information of China (English)

    常立民; 刘建华; 张瑞军; 王继东

    2004-01-01

    The morphology of carbides, as well as the generation and propagation of fatigue cracks in a wear resistant white cast iron after impact fatigue test were observed by means of optical microscope and SEM, and the relationship among the content of RE (rare earths) in the wear resistant white cast iron and the heating temperature as well as the length and propagation speed of the fatigue cracks were determined. Based on the obtained results, the effect of RE modification and heat treatment on the impact fatigue property was further studied. Experimental results show that addition of RE can defer the time required for the generation of fatigue cracks, reduce their propagation speed and increase the impact fatigue resistance. The aforesaid effect is more noticeable in case of combined RE modification with heat treatment, which can be attributed to the variation in morphology and the distribution of the eutectic carbide network.

  1. 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

  2. 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

  3. Impact of nitrogen depth profiles on the electrical properties of crystalline high-K gate dielectrics

    International Nuclear Information System (INIS)

    Highlights: • The in-situ atomic layer doping of nitrogen and post-deposition nitridation using remote NH3 plasma was used to incorporate nitrogen into the crystalline ZrO2 gate dielectrics at a low temperature.. • The impact of nitrogen depth profiles on the electrical properties of crystalline high-K gate oxides was investigated. • The CET was reduced from 1.55 nm to 1.13 nm and Jg was suppressed up to two orders of magnitude by the post-deposition nitridation. • Post-deposition nitridation contributes to higher nitrogen concentration at the top surface of ZrO2, leading to enhancement of the resistance to oxygen diffusion toward the interface and restrain the IL growth during the thermal treatment. • A low CET of 1.13 nm with a suppressed Jg of 1.35 × 10−5 A/cm2 was realized in the crystalline ZrO2 gate oxide treated with the post-deposition nitridation. - Abstract: The electrical characteristics of crystalline ZrO2 gate dielectrics with different nitrogen depth profiles were investigated, which were treated by the in-situ atomic layer doping of nitrogen and post-deposition nitridation processes, respectively, using remote NH3 plasma at a low treatment temperature of 250 °C. The crystalline ZrO2 gate dielectric of the tetragonal/cubic phase was formed by post-metallization annealing (PMA) at a low temperature of 450 °C, resulting in an increase of the dielectric constant. As compared with the in-situ atomic layer doping of nitrogen, the post-deposition nitrogen process leads to a lower capacitance equivalent thickness of 1.13 nm with a low leakage current density of 1.35 × 10−5 A/cm2. The enhanced capacitance density caused by the post-deposition nitrogen treatment may be ascribed to the high nitrogen concentration at the top surface of gate dielectric, giving rise to the suppression of oxygen diffusion from the ambient toward the interface and so a thinner interfacial layer. The result reveals that the nitrogen incorporation at the top surface

  4. Steel Processing Properties and Their Effect on Impact Deformation of Lightweight Structures

    Energy Technology Data Exchange (ETDEWEB)

    Simunovic, S

    2003-09-23

    The objective of the research was to perform a comprehensive computational analysis of the effects of material and process modeling approaches on performance of UltraLight Steel Auto Body (ULSAB) vehicle models. The research addressed numerous material related effects, impact conditions as well as analyzed the performance of the ULSAB vehicles in crashes against designs representing the current US vehicle fleet. This report is organized into three main sections. The first section describes the results of the computational analysis of ULSAB crash simulations that were performed using advanced material modeling techniques. The effects of strain-rate sensitivity on a high strength steel (HSS) intensive vehicle were analyzed. Frontal and frontal offset crash scenarios were used in a finite element parametric study of the ULSAB body structure. Comparisons are made between the crash results using the piece-wise-linear isotropic plasticity strain-rate dependent material model, and the isotropic plasticity material model based on quasi-static properties. The simulation results show the importance of advanced material modeling techniques for vehicle crash simulations due to strain-rate sensitivity and rapid hardening characteristics of advanced high strength steels. Material substitution was investigated for the main frontal crush structure using the material of similar yield stress a significantly different strain-rate and hardening characteristics. The objective of the research presented in Section 2 was to assess the influence of stamping process on crash response of ULSAB vehicle. Considered forming effects included thickness variations and plastic strain hardening imparted in the part forming process. The as-formed thickness and plastic strain for front crash parts were used as input data for vehicle crash analysis. Differences in structural performance between crash models with and without forming data were analyzed in order to determine the effects and feasibility of

  5. Bacterial ice nuclei impact cloud lifetime and radiative properties and reduce atmospheric heat loss in the BRAMS simulation model

    Science.gov (United States)

    Costa, Tassio S.; Gonçalves, Fábio L. T.; Yamasoe, Marcia A.; Martins, Jorge A.; Morris, Cindy E.

    2014-08-01

    This study examines the effect of the bacterial species Pseudomonas syringae acting as ice nuclei (IN) on cloud properties to understand its impact on local radiative budget and heating rates. These bacteria may become active IN at temperatures as warm as -2 °C. Numerical simulations were developed using the Brazilian Regional Atmospheric Model System (BRAMS). To investigate the isolated effect of bacterial IN, four scenarios were created considering only homogeneous and bacterial ice nucleation, with 1, 10 and 100 IN per cubic meter of cloud volume and one with no bacteria. Moreover, two other scenarios were generated: the BRAMS default parameterization and its combination with bacterial IN. The model reproduced a strong convective cell over São Paulo on 3 March 2003. Results showed that bacterial IN may change cloud evolution as well as its microphysical properties, which in turn influence cloud radiative properties. For example, the reflected shortwave irradiance over an averaged domain in a scenario considering bacterial IN added to the BRAMS default parameterization was 14% lower than if bacteria were not considered. Heating rates can also be impacted, especially due to differences in cloud lifetime. Results suggest that the omission of bacterial IN in numerical models, including global cloud models, could neglect relevant ice nucleation processes that potentially influence cloud radiative properties.

  6. Bacterial ice nuclei impact cloud lifetime and radiative properties and reduce atmospheric heat loss in the BRAMS simulation model

    International Nuclear Information System (INIS)

    This study examines the effect of the bacterial species Pseudomonas syringae acting as ice nuclei (IN) on cloud properties to understand its impact on local radiative budget and heating rates. These bacteria may become active IN at temperatures as warm as −2 °C. Numerical simulations were developed using the Brazilian Regional Atmospheric Model System (BRAMS). To investigate the isolated effect of bacterial IN, four scenarios were created considering only homogeneous and bacterial ice nucleation, with 1, 10 and 100 IN per cubic meter of cloud volume and one with no bacteria. Moreover, two other scenarios were generated: the BRAMS default parameterization and its combination with bacterial IN. The model reproduced a strong convective cell over São Paulo on 3 March 2003. Results showed that bacterial IN may change cloud evolution as well as its microphysical properties, which in turn influence cloud radiative properties. For example, the reflected shortwave irradiance over an averaged domain in a scenario considering bacterial IN added to the BRAMS default parameterization was 14% lower than if bacteria were not considered. Heating rates can also be impacted, especially due to differences in cloud lifetime. Results suggest that the omission of bacterial IN in numerical models, including global cloud models, could neglect relevant ice nucleation processes that potentially influence cloud radiative properties. (letter)

  7. Influence of Thermal Aging on the Mechanical and Corrosion Properties of C-22 Alloy Welds

    Energy Technology Data Exchange (ETDEWEB)

    Edgecumbe Summers, T.S.; Rebak, R.B.; Seeley, R.R.

    2000-06-15

    The phase stability of C-22 alloy (UNS No. N06022) gas tungsten arc welds was studied by aging samples at 427, 482, 538, 593, 649, 704, and 760 C for times up to 40,000 hours. The tensile properties and the Charpy impact toughness of these samples were measured in the as-welded condition as well as after aging. The corrosion resistance was measured using standard immersion tests in acidic ferric sulfate (ASTM G 28 A) and 2.5% hydrochloric acid solutions at the boiling point. The microstructures of weld samples were examined using scanning electron microscopy (SEM). One weld sample (aged 40,000 hours at 427 C) was examined using transmission electron microscopy (TEM). The structure of the unaged welds was dendritic with tetrahedrally close-packed (TCP) phase particles in the interdendritic regions. Long-range order was seen in the weld aged at 427 C for 40,000 hours and was assumed to also occur in other welds aged below approximately 600 C. At temperatures above about 600 C, TCP phase nucleation and growth of existing particles occurred. This precipitation occurred near the original particles presumably in regions of the highest molybdenum (Mo) segregation. Lower temperatures had little or no effect on the morphology of TCP phases. The C-22 weld samples were approximately 25% stronger but 30-40% less ductile than the base metal. Strengthening of the weld during aging occurred significantly only at 593 C for the aging times investigated. Because strengthening was not seen at higher temperatures, it was assumed to be due to ordering which has been seen in C-22 base metal at this temperature. A small amount of strengthening was seen at 427 C after 40,000 hours where ordering was just beginning. The Charpy impact toughness was reduced dramatically with aging. The time at which this reduction occurred decreased as aging temperature increased suggesting that the reduced ductility is due to the presence and growth of the brittle TCP phases. The corrosion rate of weld

  8. Effect of heat treatment on mechanical properties of H11 tool steel

    Directory of Open Access Journals (Sweden)

    S.Z. Qamar

    2009-08-01

    Full Text Available Purpose: AISI H11 is a special alloy steel, categorized as chromium tool steel. Because of its high toughness and hardness, it is well suited for hot work applications involving very high loads. Typical applications are hot-work forging and extrusion dies, helicopter rotor blades, etc. For longer life and higher design accuracy, properties of this type of tool steel can be improved by various types of heat treatment. Current work reports and analyzes results of mechanical testing performed on variously heat treated H11 steel samples, to arrive at an optimum heat treatment strategy for hot work applications.Design/methodology/approach: Tensile and impact test specimens were fabricated using precision milling and EDM. These samples were subjected to various heat treatment sequences, consisting of annealing, hardening, air and oil quenching, and tempering at different temperatures. Heat treated samples were then mechanically tested for hardness (Rockwell, impact toughness (Charpy, and tensile properties (yield strength, ultimate strength, ductility.Findings: Mechanical testing of H11 samples revealed that with increasing temper temperatures: (a hardness first increases to a maximum and then gradually decreases; (b impact toughness first decreases to a minimum and then increases; (c yield strength first decreases, then increases, and then increases again; (d ultimate strength first increases to a maximum and then steadily decreases; and (e ductility (% elongation gradually decreases till 600ºC, and then increases rather sharply.Practical implications: Though a very promising candidate for hot-work applications, H11 steel is not commonly used for die and tool making. Results of this study can provide die designers and users in the metalworking industry with good guidelines to select proper heat treatment strategies to use H11 steel for various applications.Originality/value: Very little information is available in published literature about

  9. Impacts and implementation of fuel moisture release and radiation properties in modelling of pulverized fuel combustion processes

    DEFF Research Database (Denmark)

    Yin, Chungen

    2015-01-01

    presents different methods for fuel moisture release and new models for gas and particle radiative properties, and demonstrates their implementation, importance and impacts in PF combustion modelling via a comprehensive CFD study of a pulverized coal-fired utility boiler. To conclude, it is recommended to......Pulverized fuels (PF) prepared and fired in utility boilers usually contain a certain amount of moisture, either free moisture or chemically bound moisture. In PF furnaces, radiation which is the principal mode of heat transfer consists of contribution from both gas and particle phase. This paper....... Therefore, cares must be taken in particle radiation, especially particle radiative properties. The refined weighted-sum-of-gray-gases model (WSGGM) and conversion-dependent particle radiative property models presented in the paper are recommended for use in generic CFD modelling of PF combustion....

  10. Impact of process temperature on GaSb metal-oxide-semiconductor interface properties fabricated by ex-situ process

    International Nuclear Information System (INIS)

    We have studied the impact of process temperature on interface properties of GaSb metal-oxide-semiconductor (MOS) structures fabricated by an ex-situ atomic-layer-deposition (ALD) process. We have found that the ALD temperature strongly affects the Al2O3/GaSb MOS interface properties. The Al2O3/GaSb MOS interfaces fabricated at the low ALD temperature of 150 °C have the minimum interface-trap density (Dit) of ∼4.5 × 1013 cm−2 eV−1. We have also found that the post-metalization annealing at temperature higher than 200 °C degrades the Al2O3/GaSb MOS interface properties. The low-temperature process is preferable in fabricating GaSb MOS interfaces in the ex-situ ALD process to avoid the high-temperature-induced degradations.

  11. Sussing Merger Trees : The Impact of Halo Merger Trees on Galaxy Properties in a Semi-Analytic Model

    CERN Document Server

    Lee, Jaehyun; Elahi, Pascal J; Thomas, Peter A; Pearce, Frazer R; Behroozi, Peter; Han, Jiaxin; Helly, John; Jung, Intae; Knebe, Alexander; Mao, Yao-Yuan; Onions, Julian; Rodriguez-Gomez, Vicente; Schneider, Aurel; Srisawat, Chaichalit; Tweed, Dylan

    2014-01-01

    A halo merger tree forms the essential backbone of a semi-analytic model for galaxy formation and evolution. Recent studies have pointed out that extracting merger trees from numerical simulations of structure formation is non-trivial; different tree building algorithms can give differing merger histories. These differences should be carefully understood before merger trees are used as input for models of galaxy formation. We investigate the impact of different halo merger trees on a semi-analytic model. We find that the z=0 galaxy properties in our model show differences between trees when using a common parameter set. The star formation history of the Universe and the properties of satellite galaxies can show marked differences between trees with different construction methods. Independently calibrating the semi-analytic model for each tree can reduce the discrepancies between the z=0 global galaxy properties, at the cost of increasing the differences in the evolutionary histories of galaxies. Furthermore, ...

  12. The Impact of Solar Panels on the Price and Saleability of Domestic Properties in Oxford

    OpenAIRE

    Charlie Morris-Marsham; Gemma Moore

    2011-01-01

    Studies into energy efficiency and micro-generation in the built environment tend to focus on the economic or environmental paybacks of installed technologies. However, as the opening quote suggests, features that reduce the energy consumption of a property may also play a role in influencing property value. To date research into whether and to what extent energy efficiency and micro-generation technologies, such as solar panels, affect the price and saleability of properties has been limited...

  13. Effect of heat treatment and cleanness of ultra low carbon bainitic (ULCB) steel on its impact toughness

    International Nuclear Information System (INIS)

    The small variations in sulphur and carbon concentrations can have a major influence on the impact transition temperature (ITT) of ultra low carbon HSLA-100 steel which has been quenched in water and tempered (WQ and T). Since the average carbon concentration is very low thus sensitivity of ITT to heat treatment parameters depends also on the yield strength increase due to precipitation effect of εCu phase. The regression analysis has been used to establish equations taking into account those parameters. The properties of a mixed microstructure formed from partially austenitic regions have been also considered. The fine austenitic grains transform into more desirable fine bainitic ferrite phases with lower hardness values and higher toughness. On the other hand, if cooling rate is sufficiently large, then the carbon enriched austenite transforms partially into hard martensite and some of remaining untransformed austenite being retained to ambient temperature. Because hard martensite islands are located in much softer surroundings consisting of tempered ferrite, they do not cause a general reduction in impact toughness tests. Due to further grain refinement of microstructure the measured toughness on Charpy V specimens can be very high at low temperatures. The very detrimental effect of sulphur in ULCB steel has been confirmed by presented results. (author)

  14. Low velocity impact properties of intra-ply hybrid composites based on basalt and nylon woven fabrics

    International Nuclear Information System (INIS)

    In this paper, the low velocity impact behavior of homogenous and hybrid composite laminates reinforced by basalt-nylon intra-ply fabrics was experimentally investigated. Epoxy resin was used as matrix material. The purpose of using this hybrid composite is to combine the good mechanical properties of basalt fiber with the excellent impact resistant of nylon fiber. Five different types of woven fabrics were used as reinforcement with different volume percentages of nylon (0%, 25%, 33.3%, 50% and 100%). The effect of nylon/basalt fiber content on maximum force, maximum deflection, residual deflection, total absorbed energy, elastic energy, size and type of damage were studied at several low velocity impact nominal energy levels (16, 30 and 40 J). The results indicate that impact performance of these composites is significantly affected by the nylon/basalt fiber content. The visual inspection and ultrasonic C-scan of the impact damaged specimens reveals that content of nylon/basalt fiber controls the type and size of damage.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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...

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

    OpenAIRE

    Aleksandra Duda-Chodak; Tomasz Tarko; Łukasz Wajda; Bożena Kręcioch

    2015-01-01

    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 assess...

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

    OpenAIRE

    Il'inykh Galina Viktorovna; Korotaev Vladimir Nikolayevich; Vaysman Yakov Iosifovich

    2014-01-01

    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 algor...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-04-01

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

  3. 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

  4. Carbon and glass hierarchical fibers: Influence of carbon nanotubes on tensile, flexural and impact properties of short fiber reinforced composites

    International Nuclear Information System (INIS)

    Highlights: ► Dense CNT were grown on carbon fiber and glass fiber by use of floating catalyst CVD method. ► CNT showed different growing mechanism on carbon and glass fiber. ► Short fiber-CNT-composites showed enhanced mechanical properties. ► CNT coating enhanced fiber–matrix interaction and acted as additional reinforcement. -- Abstract: Dense carbon nanotubes (CNTs) were grown uniformly on the surface of carbon fibers and glass fibers to create hierarchical fibers by use of floating catalyst chemical vapor deposition. Morphologies of the CNTs were investigated using scanning electronic microscope (SEM) and transmission electron microscope (TEM). Larger diameter dimension and distinct growing mechanism of nanotubes on glass fiber were revealed. Short carbon and glass fiber reinforced polypropylene composites were fabricated using the hierarchical fibers and compared with composites made using neat fibers. Tensile, flexural and impact properties of the composites were measured, which showed evident enhancement in all mechanical properties compared to neat short fiber composites. SEM micrographs of composite fracture surface demonstrated improved adhesion between CNT-coated fiber and the matrix. The enhanced mechanical properties of short fiber composites was attributed to the synergistic effects of CNTs in improving fiber–matrix interfacial properties as well as the CNTs acting as supplemental reinforcement in short fiber-composites.

  5. Impact of Associated Gases on Equilibrium and Transport Properties of a Stream: Molecular Simulation and Experimental Studies

    Science.gov (United States)

    Creton, Benoit; de Bruin, Theodorus; Le Roux, Dominique; Duchet-Suchaux, Pierre; Lachet, Véronique

    2014-02-01

    During the various carbon dioxide capture and storage (CCS) stages, an accurate knowledge of thermodynamic properties of streams is required for the correct sizing of plant units. The injected streams are not pure and often contain small amounts of associated gaseous components such as , , noble gases, etc. In this work, the thermodynamic behavior and transport properties of some -rich mixtures have been investigated using both experimental approaches and molecular simulation techniques such as Monte Carlo and molecular dynamics simulations. Using force fields available in the literature, we have validated the capability of molecular simulation techniques in predicting properties for pure compounds, binary mixtures, as well as multicomponent mixtures. These validations were performed on the basis of experimental data taken from the literature and the acquisition of new experimental data. As experimental data and simulation results were in good agreement, we proposed the use of simulation techniques to generate new pseudo-experimental data and to study the impact of associated gases on the properties of streams. For instance, for a mixture containing 92.0 mol% of , 4.0 mol% of , 3.7 mol% of Ar, and 0.3 mol% of , we have shown that the presence of associated gases leads to a decrease of 14 % and 21 % of the dense phase density and viscosity, respectively, as compared to pure properties.

  6. Effects of Cu and B addition on microstructure and mechanical properties of high-strength bainitic steels

    International Nuclear Information System (INIS)

    Effects of Cu and B addition on microstructure and mechanical properties of high-strength bainitic steels were investigated in this study. Six kinds of steels were fabricated by controlling the amount of Cu and B addition, and their microstructures and tensile and Charpy impact properties were investigated. Their effective grain sizes were also characterized by the electron back-scatter diffraction analysis. The tensile test results indicated that the B- or Cu-containing steels had the higher yield and tensile strengths than the B- or Cu-free steels because their volume fractions of acicular ferrite and martensite were quite high. The B- or Cu-free steels had the higher upper shelf energy than the B- or Cu-containing steels because of their lower volume fraction of martensite. In the steel containing 10 ppm B without Cu, the best combination of high strengths, high upper shelf energy, and low energy transition temperature could be obtained by the decrease in effective grain size due to the presence of acicular ferrite having fine effective grain size.

  7. Investigation of the mechanical properties and microstructure of W and WLa203 after high-speed hot extrusion

    International Nuclear Information System (INIS)

    Full text of publication follows: Tungsten and tungsten-base materials are considered as promising materials for facing plasma components in fusion reactors, due their good thermomechanical properties, high melting temperature and low hydrogen solubility. Unfortunately these materials are brittle at low and intermediate temperatures. The aim of this work is to improve the ductility of W and W-base materials by high-speed hot extrusion. Two different materials W and W-La2O3, were hot extruded in a vertical press at 1000 deg. C, under a pressure of 1.7 GPa and using a high extrusion speed of 104 s-1. Following high speed hot extrusion, the W rod was observed to contain a lot of cracks, while a W-La2O3 rod with a diameter of 10 mm was successfully produced without any cracks. W-La2O3 appears clearly more ductile than W under high-speed hot extrusion. Microhardness measurements showed that the hardness of W increases slightly from 4550 to 4580 MPa, as a result from high-speed hot extrusion, while the hardness of W-La2O3 decreases from 5100 to 4670 MPa. In order to correlate mechanical properties to the microstructure extruded rods are being investigated by means of Charpy impact and tensile tests and scanning and transmission electron microscopy observations. (authors)

  8. On the comparison of microstructural characteristics and mechanical properties of high-vanadium austenitic manganese steels with the Hadfield steel

    International Nuclear Information System (INIS)

    Highlights: ► Mechanical properties of HV-AMS are affected by the type and distribution of VCs. ► Solution treatment of Hadfield steels has no significant effect on HV-AMS alloys. ► HV-AMS alloys have superior wear resistance compared with Hadfield steels. - Abstract: In this study, high-vanadium austenitic manganese steel (HV-AMS) alloys and the standard Hadfield steel were investigated. The microstructure of these high-vanadium alloyed Hadfield steels was studied thoroughly using optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) and was compared to the Hadfield steel. The hardness and unnotched Charpy impact strength of HV-AMS alloys and Hadfield steel were examined at ambient temperature in the as-cast and heat-treated conditions. A pin-on-disk wear test at linear speed of 10 m/min and a 55 N normal load was employed to evaluate the wear behavior of both steel samples. Microstructural results showed that varying the carbon content in HV-AMS alloys can affect the vanadium carbide morphology and its distribution in the austenite matrix which leads to considerable changes of the mechanical properties. Abrasion test revealed that HV-AMS alloys have superior wear resistance, about 5 times of the standard Hadfield steel.

  9. Effect of vanadium and titanium modification on the microstructure and mechanical properties of a microalloyed HSLA steel

    International Nuclear Information System (INIS)

    DMR-249A is a low carbon microalloyed high-strength low-alloy (HSLA) steel. While DMR-249A plates of thickness less than 18 mm meet the specified room temperature yield strength (390 MPa) and Charpy impact toughness (78J at -60 deg. C) in the as-rolled condition, thicker plates require water quenching and tempering. Elimination of the quenching and tempering treatment can result in significant cost and energy savings besides offering increased productivity. Therefore, in the present work, modifications to the base DMR-249A steel composition have been investigated with the objective of producing thicker gage plates (24 mm) capable of meeting the specified properties in the normalized condition. Plates from three modified compositions i.e., containing 0.015 wt.% titanium and 0.06, 0.09 and 0.12 wt.% vanadium respectively and one composition with 0.10 wt.% vanadium, and without any titanium were investigated over a range of normalizing temperatures (875-1000 deg. C). In all cases, only the steel without titanium met the specified properties in the normalized condition. Microstructural investigations using scanning and transmission electron microscopy, as well as support evidence from calculations performed using ThermoCalc software, suggest that this is due to the presence of nanoscale vanadium rich carbonitride particles distributed throughout the matrix. These particles were absent in the titanium-containing steel at a similar vanadium level.

  10. Effect of vanadium and titanium modification on the microstructure and mechanical properties of a microalloyed HSLA steel

    Energy Technology Data Exchange (ETDEWEB)

    Show, B.K., E-mail: bijay_show@rediffmail.com [Defence Metallurgical Research Laboratory, Kanchanbagh P.O., Hyderabad 500058, Andhra Pradesh (India); Veerababu, R., E-mail: veeru_met@yahoo.com [Defence Metallurgical Research Laboratory, Kanchanbagh P.O., Hyderabad 500058, Andhra Pradesh (India); Balamuralikrishnan, R., E-mail: bmk_pgh@yahoo.com [Defence Metallurgical Research Laboratory, Kanchanbagh P.O., Hyderabad 500058, Andhra Pradesh (India); Malakondaiah, G., E-mail: director@dmrl.drdo.in [Defence Metallurgical Research Laboratory, Kanchanbagh P.O., Hyderabad 500058, Andhra Pradesh (India)

    2010-03-15

    DMR-249A is a low carbon microalloyed high-strength low-alloy (HSLA) steel. While DMR-249A plates of thickness less than 18 mm meet the specified room temperature yield strength (390 MPa) and Charpy impact toughness (78J at -60 deg. C) in the as-rolled condition, thicker plates require water quenching and tempering. Elimination of the quenching and tempering treatment can result in significant cost and energy savings besides offering increased productivity. Therefore, in the present work, modifications to the base DMR-249A steel composition have been investigated with the objective of producing thicker gage plates (24 mm) capable of meeting the specified properties in the normalized condition. Plates from three modified compositions i.e., containing 0.015 wt.% titanium and 0.06, 0.09 and 0.12 wt.% vanadium respectively and one composition with 0.10 wt.% vanadium, and without any titanium were investigated over a range of normalizing temperatures (875-1000 deg. C). In all cases, only the steel without titanium met the specified properties in the normalized condition. Microstructural investigations using scanning and transmission electron microscopy, as well as support evidence from calculations performed using ThermoCalc software, suggest that this is due to the presence of nanoscale vanadium rich carbonitride particles distributed throughout the matrix. These particles were absent in the titanium-containing steel at a similar vanadium level.

  11. 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

  12. Effect of initial microstructures on the properties of Ferrite-Martensite Dual-Phase pipeline steels with Strain-Based design

    Directory of Open Access Journals (Sweden)

    Yueyue Hu

    2012-04-01

    Full Text Available This study aims to investigate the effect of initial microstructures on the properties of ferrite-martensite dual-phase pipeline steels with strain-based design. For this purpose, the as-received acicular ferrite steels were first austenitized at 920 ºC for 15 minutes followed by air cooling and water quenching to produce ferrite-pearlite and ferrite-martensite microstructure, respectively. Subsequently, the steels with ferrite-pearlite, ferrite-martensite and as-received acicular ferrite microstructure were intercritically annealed at 820 ºC for 10 minutes followed by water quenching to produce three different ferrite-martensite dual-phase microstructures. Tensile tests, Vickers hardness and Charpy impact tests were carried out to investigate the mechanical properties. Scanning electron microscope was used to analyze the microstructures and tensile fractographs. The results showed that all the tensile specimens of these three different ferrite-martensite dual-phase steels fractured in ductile mode, however, their microstructures and mechanical properties varied significantly. By contrast, the ferrite-martensite dual-phase steel derived from acicular ferrite initial microstructure had optimal combination of the strength, toughness and deformability, which provided a good candidate for the pipeline steels with strain-based design used in severe geological environments.

  13. Review of effects of long-term aging on the mechanical properties and microstructures of Types 304 and 316 stainless steel

    International Nuclear Information System (INIS)

    Because commercial liquid metal fast breeder reactor (LMFBR) are designed to last for 40 years or more, an understanding of the mechanical behavior of the structural alloys used in them is required for times on the order of 2.5 x 105 h (assuming a 70% availability factor). Types 304 and 316 stainless steel are used extensively in LMFBR systems. At the beginning of life these alloys are in a metastable state and evolve to a more stable state and, therefore, more stable microstructure during plant operation. Correlations of microstructures and mechanical properties during aging under representative LMFBR temperature and loading conditions are desirable from the standpoint of assuring safe, reliable, and economic plant operation. We reviewed the mechanical properties and microstructures of types 304 and 316 stainless steel wrought alloys after long-term aging in air for times up to 9 x 104 h (about 10-1/2 years). The principal effect of such aging is to reduce low temperature fracture toughness (as measured by Charpy impact test) and tensile ductility. Examples are cited, however, where, because stable microstructures are achieved, these as well as strength-related properties can be expected to remain adequate for anticipated service life conditions. 16 refs., 19 figs

  14. Effect of commercial cellulases and refining on kraft pulp properties: correlations between treatment impacts and enzymatic activity components.

    Science.gov (United States)

    Cui, Li; Meddeb-Mouelhi, Fatma; Laframboise, François; Beauregard, Marc

    2015-01-22

    The importance of enzymes as biotechnological catalysts for paper industry is now recognized. In this study, five cellulase formulations were used for fibre modification. The number of PFI revolutions decreased by about 50% while achieving the same freeness value (decrease in CSF by 200 mL) with the enzymatic pretreatment. The physical properties of handsheets were modified after enzymatic pretreatment followed by PFI refining. A slight decrease in tear strength was observed with enzymes C1 and C4 at pH 7 while the most decrease in tear was observed after C2, C3, C5 treatments. C1 and C4 which had xylanase activity improved paper properties, while other enzymes had a negative impact. Therefore, the intricate balance between cellulolytic and hemicellulolytic activity is the key to optimizing biorefining and paper properties. It was also observed that C1 impact was pH dependent, which supports the importance of pH in developing an enzymatic strategy for refining energy reduction. PMID:25439885

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

    OpenAIRE

    Tosi., M

    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.

  16. Impact of Wetting/Oven-Drying Cycles on the Mechanical and Physical Properties of Birch Plywood

    Science.gov (United States)

    Sooru, M.; Kasepuu, K.; Kask, R.; Lille, H.

    2015-11-01

    The objective of this study was to explore some physical and mechanical properties and the dimensional stability of birch (Betula sp.) nine-ply veneers glued with phenol-formaldehyde (PF) after 10 cycles of soaking/oven-drying. The properties to be determined were bending strength (BS), modulus of elasticity in bending (MOE), Janka hardness (JH) and thickness swelling (TS), which were tested according to the European Standards (EN). An analytical equation was used for approximation of the change in the physical and mechanical properties of the samples depending on the number of cycles. It was shown that the values of the studied properties were affected most by the first soaking and drying cycles after which BS and MOE decreased continuously while the values of JH and TS stabilized. After 10 cycles the final values of BS, MOE, JH and TS accounted for 75-81%, 95%, 82% and 98.5% of the initial values, respectively.

  17. Privatization in Eastern Europe: The Impact on Economic Development through the Protection of Property Rights

    OpenAIRE

    T.G. Geurts

    2005-01-01

    The transitional economies of Eastern Europe are in the long process of making the switch of a planned economy to a more capitalist economy. An important aspect of a capitalist economy, if not the most important aspect that characterizes the degree of capitalism, is the protection of private property rights. It is well documented that a weak protection of private property rights will lead to fewer investments, in particular in real estate, given the fact that real estate is very illiquid. On ...

  18. The impact of social housing developments on nearby property prices: A Nelson Mandela Bay Case Study

    OpenAIRE

    du Preez, M; M.C. Sale

    2011-01-01

    Social housing projects often face substantial “Not-in-my-backyard†(NIMBY) sentiment and as a result are frequently plagued by local opposition from communities who argue that nearby property prices will be affected adversely by these developments. International hedonic pricing studies conducted have, however, produced mixed results with some concluding that social housing developments may in fact lead to an improvement in surrounding property values. There is, however, a paucity of South...

  19. Relationships between micromorphology and impact properties of injection moulded isotactic polypropylene

    OpenAIRE

    Murphy, Mark William

    1986-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. The micromorphology and properties of injection moulded semi-crystalline polymers can be significantly modified by changes in the injection moulding parameters and the design of mould. Further modifications to the microstructure and properties occur following the incorporation of additives into a thermoplastic compound, such as stabilisers, pigments, nucleants, etc. Many published papers refe...

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

    OpenAIRE

    Endah Saptutyningsih

    2013-01-01

    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 relati...