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Sample records for specimen size effect

  1. Specimen size effects in Charpy impact testing

    International Nuclear Information System (INIS)

    Alexander, D.J.; Klueh, R.L.

    1989-01-01

    Full-size , half-size, and third-size specimens from several different steels have been tested as part of an ongoing alloy development program. The smaller specimens permit more specimens to be made from small trail heats and are much more efficient for irradiation experiments. The results of several comparisons between the different specimen sizes have shown that the smaller specimens show qualitatively similar behavior to large specimens, although the upper-shelf energy level and ductile-to-ductile transition temperature are reduced. The upper-shelf energy levels from different specimen sizes can be compared by using a simple volume normalization method. The effect of specimen size and geometry on the ductile-to-ductile transition temperature is more difficult to predict, although the available data suggest a simple shift in the transition temperature due to specimen size changes.The relatively shallower notch used in smaller specimens alters the deformation pattern, and permits yielding to spread back to the notched surface as well as through to the back. This reduces the constraint and the peak stresses, and thus the initiation of cleavage is more difficult. A better understanding of the stress and strain distributions is needed. 19 refs., 3 figs., 3 tabs

  2. Effects of drying conditions, admixtures and specimen size on shrinkage strains

    International Nuclear Information System (INIS)

    Al-Saleh, Saleh A.; Al-Zaid, Rajeh Z.

    2006-01-01

    The paper presents the results of an experimental investigation on the effects of drying conditions, specimen size and presence of plasticizing admixture on the development of shrinkage strains. The measurements are taken in a harsh (50 deg. C and 5% R.H.) and a moderate environment (28 deg. C and 50% R.H.). The results include strain development at various levels of cross sections of concrete prisms. The drying conditions are found to be the dominant parameter affecting the shrinkage strain development particularly in specimens of smaller sizes. The effect of plasticizing admixture on shrinkage strains is negligible

  3. The quantification of specimen size effects in the ductile-brittle transition for C-Mn steel

    International Nuclear Information System (INIS)

    Knee, N.; Worthington, P.J.; Moskovic, R.

    1989-02-01

    It is now generally accepted that the temperature range of the brittle to ductile transition, determined using fracture mechanics specimens, is dependent of the specimen size for ferritic steels. This size effect arises through increasing constraint at the crack tip as the specimen thickness increases together with an increasing volume of material sampled. The size effect can be quantified in terms of a shift in temperature for a given toughness level. This was determined in the present work from fracture toughness/temperature curves obtained by performing fracture toughness tests on eight 100 mm thick compact tension specimens and 40 25 mm thick compact tension specimens over the ductile-brittle transition range of a C-Mn steel. The emphasis is on the development of a practical methodology to quantify the size effect from a limited but still appreciable number of tests. (author)

  4. Effect of specimen size on the fracture toughness of Type 304 stainless steel. Interim report

    International Nuclear Information System (INIS)

    Mills, W.J.

    1982-02-01

    The effect of specimen size on the elastic-plastic fracture toughness behavior of Type 304 stainless steel was characterized by the multiple-specimen J-R curve technique at 427 0 C. Fracture tests were performed on five compact specimen sizes: 2.5T (thickness = 63.5 mm), 2.5T (thickness = 14.7 mm), 1T (thickness = 25.4 mm), 1T (thickness = 14.7 mm), and 0.577 (thickness = 14.7 mm). In comparison with the 63.5-mm thick 2.5T specimen results, the smaller specimens exhibited higher J/sub Ic values and lower R-curve slopes (dJ/da). However, the differences in J/sub Ic/ and dJ/da were not statistically significant for the 2.5T and 1T specimens, which suggests that size effects for 1T and larger specimens are relatively small or nonexistant. On the other hand, there was a statistical difference between the 0.577T and 2.5T J/sub Ic/ values

  5. Size effect studies on smooth tensile specimens at room temperature and 400 oC

    International Nuclear Information System (INIS)

    Krompholz, K.; Kamber, J.; Groth, E.; Kalkhof, D.

    2000-06-01

    One of the objectives of the REVISA project (REactor Vessel Integrity in Severe Accidents) is to assess the size effect related to deformation and failure models as well as material data under quasistatic and dynamic conditions in homogeneous and non-homogeneous states of strain. For these investigations the reactor pressure vessel material 20 MnMoNi 55 was selected. It was subjected to a size effect study on smooth scaled tensile specimens of three sizes. Two strain rates (2*10 -5 /s and 10 -3 /s) and two temperatures (room temperature and 400 o C) were selected. The investigations are aimed at a support for a gradient plasticity approach to size effects. Test on the small specimens (diameters 3 and 9 mm) were performed at an electromechanical test machine, while the large specimens (diameter 30 mm) had to be tested at a servohydraulical closed loop test machine with a force capacity of 1000 kN

  6. Size effect studies on smooth tensile specimens at room temperature and 400 {sup o}C

    Energy Technology Data Exchange (ETDEWEB)

    Krompholz, K.; Kamber, J.; Groth, E.; Kalkhof, D

    2000-06-15

    One of the objectives of the REVISA project (REactor Vessel Integrity in Severe Accidents) is to assess the size effect related to deformation and failure models as well as material data under quasistatic and dynamic conditions in homogeneous and non-homogeneous states of strain. For these investigations the reactor pressure vessel material 20 MnMoNi 55 was selected. It was subjected to a size effect study on smooth scaled tensile specimens of three sizes. Two strain rates (2*10{sup -5}/s and 10{sup -3}/s) and two temperatures (room temperature and 400 {sup o}C) were selected. The investigations are aimed at a support for a gradient plasticity approach to size effects. Test on the small specimens (diameters 3 and 9 mm) were performed at an electromechanical test machine, while the large specimens (diameter 30 mm) had to be tested at a servohydraulical closed loop test machine with a force capacity of 1000 kN.

  7. LISSAC - size and geometry effects on the failure behaviour of notched specimens

    International Nuclear Information System (INIS)

    Seidenfuss, M.; Roos, E.

    2004-01-01

    In the current German design codes, mainly stress based concepts are used in the safety analysis of technical components. However, no reliable limit loads or safety margins can be defined with these concepts. Validated concepts on the basis of a tolerable limit strain are presently not available. In the context of the EU program LISSAC specimens with different geometry as well as geometrically similar specimens with a size ratio up to 1:50 are examined. On the basis of finite element simulations it is shown that damage models are able to predict the experimentally observed geometry and size effects on the failure strains. (orig.)

  8. Size effect studies on notched tensile specimens at room temperature and 400 {sup o}C

    Energy Technology Data Exchange (ETDEWEB)

    Krompholz, K.; Kamber, J.; Groth, E.; Kalkhof, D

    2000-07-01

    One of the objectives of the REVISA project (REactor Vessel Integrity in Severe Accidents) is to assess the size effect related to deformation and failure models as well as material data under quasistatic and dynamic conditions in homogeneous and non-homogeneous states of strain. For these investigations the reactor pressure vessel material 20 MnMoNi 55 was selected. It was subjected to a size effect study on notched scaled tensile specimens of three sizes. Two strain rates (2*10{sup -5}/s and 10{sup -3}/s) and two temperatures (room temperature and 400 {sup o}C) were selected. The investigations are aimed at a support for a gradient plasticity approach to size effects. Test on the small specimens (diameters 2.4 and 7.2 mm) were performed at an electromechanical test machine, while the large specimens (diameter 24 mm) had to be tested at a servohydraulical closed loop test machine with a force capacity of 1000 kN. All characteristic values were found to be size dependent. A selected semicircular notch retains its shape. The notch opening becomes a chord of a segment of a circle, the notch shape at fracture is a segment of a circle. (author)

  9. Size effect studies on geometrically scaled three point bend type specimens with U-notches

    Energy Technology Data Exchange (ETDEWEB)

    Krompholz, K.; Kalkhof, D.; Groth, E

    2001-02-01

    One of the objectives of the REVISA project (REactor Vessel Integrity in Severe Accidents) is to assess size and scale effects in plastic flow and failure. This includes an experimental programme devoted to characterising the influence of specimen size, strain rate, and strain gradients at various temperatures. One of the materials selected was the forged reactor pressure vessel material 20 MnMoNi 55, material number 1.6310 (heat number 69906). Among others, a size effect study of the creep response of this material was performed, using geometrically similar smooth specimens with 5 mm and 20 mm diameter. The tests were done under constant load in an inert atmosphere at 700 {sup o}C, 800 {sup o}C, and 900 {sup o}C, close to and within the phase transformation regime. The mechanical stresses varied from 10 MPa to 30 MPa, depending on temperature. Prior to creep testing the temperature and time dependence of scale oxidation as well as the temperature regime of the phase transformation was determined. The creep tests were supplemented by metallographical investigations.The test results are presented in form of creep curves strain versus time from which characteristic creep data were determined as a function of the stress level at given temperatures. The characteristic data are the times to 5% and 15% strain and to rupture, the secondary (minimum) creep rate, the elongation at fracture within the gauge length, the type of fracture and the area reduction after fracture. From metallographical investigations the accent's phase contents at different temperatures could be estimated. From these data also the parameters of the regression calculation (e.g. Norton's creep law) were obtained. The evaluation revealed that the creep curves and characteristic data are size dependent of varying degree, depending on the stress and temperature level, but the size influence cannot be related to corrosion or orientation effects or to macroscopic heterogeneity (position effect

  10. Specimen size effect considerations for irradiation studies of SiC/SiC

    Energy Technology Data Exchange (ETDEWEB)

    Youngblood, G.E.; Henager, C.H. Jr.; Jones, R.H. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-10-01

    For characterization of the irradiation performance of SiC/SiC, limited available irradiation volume generally dictates that tests be conducted on a small number of relatively small specimens. Flexure testing of two groups of bars with different sizes cut from the same SiC/SiC plate suggested the following lower limits for flexure specimen number and size: Six samples at a minimum for each condition and a minimum bar size of 30 x 6.0 x 2.0 mm{sup 3}.

  11. Effects of specimen size on the flexural strength and Weibull modulus of nuclear graphite IG-110, NBG-18, and PCEA

    International Nuclear Information System (INIS)

    Chi, Se-Hwan

    2015-01-01

    Changes in flexural strength and Weibull modulus due to specimen size were investigated for three nuclear graphite grades, IG-110, NBG-18, and PCEA, using four-point-1/3 point (4-1/3) loading with specimens of three different sizes: 3.18 (Thickness) × 6.35 (Width) × 50.8 (Length), 6.50 (T) × 12.0 (W) × 52.0 (L), 18.0 (T) × 16.0 (W) × 64 (L) (mm) (total: 210 specimens). Results showed some specimen size effects were grade dependent: While NBG-18 (a) showed rather significant specimen size effects (37% difference between the 3 T and 18 T), the differences in IG-110 and PCEA were 7.6–15%. The maximum differences in flexural strength due to specimen size were larger in the PCEA and NBG-18 having larger sized coke particles (medium grain size: >300 μm) than the IG-110 with super fine coke particle size (25 μm). The Weibull modulus showed a data population dependency, in that it decreased with increasing numbers of data used for modulus determination. A good correlation between the fracture surface roughness and the flexural strength was confirmed

  12. Influence of specimen size on the creep of rock salt

    International Nuclear Information System (INIS)

    Senseny, P.E.

    1982-01-01

    Triaxial compression creep data for Avery Island dome salt are analyzed to determine the influence of specimen size on creep deformation. Laboratory experiments were performed on 50- and 100-mm-diameter specimens in the temperature range from 25 to 200 0 C and the axial stress difference range from 2.5 to 31.0 MPa. The strain-vs-time data from each test are divided into transient and steady-state components. Results of statistical analysis of these data show that transient creep of the small specimens is a stronger function of stress, temperature, and time than is transient creep of the larger specimens. Analysis of the steady-state data show no size effect, however. 14 references, 7 figures, 3 tables

  13. Test methodology and technology of fracture toughness for small size specimens

    Energy Technology Data Exchange (ETDEWEB)

    Wakai, E.; Takada, F.; Ishii, T.; Ando, M. [Japan Atomic Energy Agency, Naga-gun, Ibaraki-ken (Japan); Matsukawa, S. [JNE Techno-Research Co., Kanagawa-ken (Japan)

    2007-07-01

    Full text of publication follows: Small specimen test technology (SSTT) is required to investigate mechanical properties in the limited availability of effective irradiation volumes in test reactors and accelerator-based neutron and charged particle sources. The test methodology guideline and the manufacture processes for very small size specimens have not been established, and we would have to formulate it. The technology to control exactly the load and displacement is also required in the test technology under the environment of high dose radiation produced from the specimens. The objective of this study is to examine the test technology and methodology of fracture toughness for very small size specimens. A new bend test machine installed in hot cell has been manufactured to obtain fracture toughness and DBTT (ductile - brittle transition temperature) of reduced-activation ferritic/martensitic steels for small bend specimens of t/2-1/3PCCVN (pre-cracked 1/3 size Charpy V-notch) with 20 mm length and DFMB (deformation and fracture mini bend specimen) with 9 mm length. The new machine can be performed at temperatures from -196 deg. C to 400 deg. C under unloading compliance method. Neutron irradiation was also performed at about 250 deg. C to about 2 dpa in JMTR. After the irradiation, fracture toughness and DBTT were examined by using the machine. Checking of displacement measurement between linear gauge of cross head's displacement and DVRT of the specimen displacement was performed exactly. Conditions of pre-crack due to fatigue in the specimen preparation were also examined and it depended on the shape and size of the specimens. Fracture toughness and DBTT of F82H steel for t/2-1/3PCCVN, DFMB and 0.18DCT specimens before irradiation were examined as a function of temperature. DBTT of smaller size specimens of DFMB was lower than that of larger size specimen of t/2-1/3PCCVN and 0.18DCT. The changes of fracture toughness and DBTT due to irradiation were also

  14. Effect of sized and specimen geometry on the initiation and propagation of the ductile fracture

    International Nuclear Information System (INIS)

    Frund, J.M.; Marini, B.; Bethmont, M.

    1994-02-01

    Strength to the fracture of the pipe in PWR has to be justified with mechanical analyses. These tests are based on the strength to ductile fracture of steels which are tested in lab. The values of resistance to fracture are obtained through tensile tests on CT specimens (determination of J-R curves). The purpose of this study is to justify the sizes of the specimens which have to be used to characterize the strength to ductile fracture of steel in secondary pipes. Tests were conducted on 0,5T-CT, 1T-CT and 2T-CT specimens. Two materials with different suffer contents were studied. The test results show that the JO,2 values gotten from the different specimens are similar. But the strength to ductile fracture in 2T-CT specimens in lower than the one measured in 0,5t-CT and 1T-CT specimens. The surface of fracture of the different specimens displays splits perpendicular to the notch and parallel to the sheet surface. These splits are produced by the separation of the manganese sulfur inclusions. The effect notes on the J-R curves seems to be relevant to these splits. The reason why these splits might be responsible for a decrease of the tearing modulus are not clearly defined up to this point. The results which have been published show the importance of the geometry effects (presence or not of lateral notches...) and the loading mode on the strength to ductile fracture. We note that the curves determined from tests on CT specimens are conservative. A few preliminary studies showed that the geometry effects on resistance to fracture can be studied and explained by using local approach methods. The Rousselier modeling is useful to explain the behaviour of ferritic steels in ductile fracture. (authors). 20 refs., 7 figs., 5 tabs

  15. Effect of Specimen Shape and Size on the Compressive Strength of Foamed Concrete

    Directory of Open Access Journals (Sweden)

    Sudin M.A.S.

    2014-03-01

    Full Text Available Lightweight concrete, in the form of foamed concrete, is a versatile material that primarily consists of a cement based mortar, mixed with at least 20% volume of air. Its dry density is typically below 1600 kg/m3 with a maximum compressive strength of 15MPa. The ASTM standard provision specifies a correction factor for concrete strength of between 14 and 42Mpa, in order to compensate for a reduced strength, when the aspect height-to-diameter ratio of a specimen is less than 2.0. However, the CEB-FIP provision specifically mentions a ratio of 150mm dia. × 300mm cylinder strength to 150 mm cube strength; though, both provision requirements do not specifically clarify the applicability and/or modification of the correction factors for the compressive strength to lightweight concrete (in this case, foamed concrete. The focus of this work is to study the effect of specimen size and shape on the axial compressive strength of concrete. Specimens of various sizes and shapes were cast with square and circular cross-sections i.e., cubes, prisms, and cylinders. Their compression strength behaviours at 7 and 28 days were investigated. The results indicate that, as the CEB-FIP provision specified, even for foamed concrete, 100mm cubes (l/d = 1.0 produce a comparable compressive strength with 100mm dia. × 200mm cylinders (l/d = 2.0.

  16. Fracture toughness of Charpy-size compound specimens and its application in engineering

    International Nuclear Information System (INIS)

    Zhang, X.P.; Shi, Y.W.

    1994-01-01

    The use of a pre-cracked Charpy-size specimen with a side-groove to evaluate the fracture toughness of materials has been researched and considered. This method not only satisfies the demand for small-size specimens in surveillance tests of fracture toughness but also avoids using complicated physical methods to monitor the initial conditions of crack propagation. For most materials this method has solved the problem in which the small-size specimen did not satisfy the valid conditions of a fracture toughness measurement. In order to obtain more information from neutron-irradiated sample specimens and raise the reliability of fracture toughness surveillance tests, it has been considered more important to repeatedly exploit the broken Charpy-size specimen tested in the surveillance test, and to make it renewable. In this work, on the renewing design and utilization of Charpy-size specimens, nine data on fracture toughness can be obtained from one pre-cracked side-grooved Charpy-size specimen, while at present usually only one to three data on fracture toughness can be obtained from one Charpy-size specimen. Thus, it is found that the new method would improve the reliability of fracture toughness surveillance testing and evaluation. In addition, some factors that affect the optimum design of pre-cracked deep side-groove Charpy-size compound specimens have also been discussed. (author)

  17. Role of specimen size upon the measured toughness of cellular solids

    International Nuclear Information System (INIS)

    Christodoulou, I; Tan, P J

    2013-01-01

    It is well known that the mechanical properties of cellular solids depend critically upon the specimen size and that a 'sufficiently' large test specimen is needed to obtain representative bulk values. Notwithstanding, the fracture toughness of cellular solids is still measured experimentally based on standards, such as the ASTM E399 and E813, developed for solid materials that do not possess an intermediate, 'cell-level' length scale. Experimental data in the literature appears to show that the toughness of stochastic 3D foams is, also, size-dependent. This paper presents the results of a detailed finite element (FE) study that will quantify, and identify the physical origin of, the size-dependent effect. Three-point bending of a single-edge notched (or SEN(B)) specimen, with a 2D Voronoi micro-architecture, is modelled numerically to obtain estimates of fracture toughness which are compared to those obtained with a 'boundary-layer' analysis

  18. MR evaluation of postmenopausal ovarian size. Comparison with surgical specimen

    International Nuclear Information System (INIS)

    Joja, Ikuo; Ishida, Kana; Matsushita, Toshi; Mimura, Seiichi; Yamaguchi, Takuya; Akagi, Noriaki; Miyagi, Yasunari; Hara, Takeshi; Kanazawa, Susumu

    2008-01-01

    We investigated ovarian size after menopause using magnetic resonance (MR) imaging and gross specimens obtained from patients with uterine cancer after menopause in whom normal ovaries were confirmed at the time of surgery. The relationships between size of ovarian long axis and age, the number of years since menopause, and age at menopause were statistically evaluated for 130 ovaries observed in short-axis T 2 -weighted MR images of the uterine corpus and in 147 ovarian gross specimens. No significant relationships were found between size of ovarian long axis and these 3 factors. When the sizes of the ovaries in MR images were compared with those in gross specimens, the latter were larger, with a statistically significant difference. Similarly, when the sizes of the ovaries observed or not observed in MR images were compared in gross specimens, the former were larger, with a statistically significant difference. These results indicate that the size of the ovarian long axis observed in MR images does not accurately reflect the true size of the long axis, but ovarian size strongly affects visualization of the ovaries in MR images after menopause. In addition, these results indicate that there are no significant relationships between ovarian size after menopause and age, the number of years since menopause, or age at menopause. (author)

  19. Modelling of Size Effect with Regularised Continua

    Directory of Open Access Journals (Sweden)

    H. Askes

    2004-01-01

    Full Text Available A nonlocal damage continuum and a viscoplastic damage continuum are used to model size effects. Three-point bending specimens are analysed, whereby a distinction is made between unnotched specimens, specimens with a constant notch and specimens with a proportionally scaled notch. Numerical finite element simulations have been performed for specimen sizes in a range of 1:64. Size effects are established in terms of nominal strength and compared to existing size effect models from the literature. 

  20. Fracture mechanics characterisation of medium-size adhesive joint specimens

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Jacobsen, T.K.

    2004-01-01

    Medium-size specimens (glass-fibre beams bonded together by an adhesive layer were tested in four point bending to determine their load carrying capacity. Specimens having different thickness were tested. Except for onespecimen, the cracking occurred as cracking...... along the adhesive layer; initially cracking occurred along the adhesive/laminate interface, but after some crack extension the cracking took place inside the laminate (for one specimen the later part of thecracking occurred unstably along the adhesive/ laminate interface). Crack bridging by fibres...

  1. Development of stress relaxation measurement by a small size C-ring specimen method

    International Nuclear Information System (INIS)

    Shimanuki, Shizuka; Nakata, Kiyotomo; Kasahara, Shigeki; Kuniya, Jiro

    2002-01-01

    A stress relaxation measurement method has been developed by using C-ring specimens, and a specimen size effect has been evaluated taking radiation-induced stress relaxation into consideration. C-ring specimens were stressed by forcing a wedge in the gap. Giving an appropriate eccentric configuration in the half of the ring opposite the gap, the stress gradient along the circumference was eliminated in the section and the stress level could be varied by changing the gap spacing. The validity of the C-ring test method was confirmed by thermally stress relaxation experiments at annealing temperatures from 300 to 600degC for 1 min to 200 h in carbon steel: considerable stress relaxation could be measured for all levels of applied stress even at relatively low annealing temperatures. The relaxation results obtained from the C-ring test were in good agreement with those from a uniaxial tensile stress relaxation test. The smaller C-ring specimen with about 40 mm diameter, which is required for radiation-induced stress relaxation test, also showed adequate accuracy on stress relaxation at 600 to 830degC in stainless steel, compared with the large size C-ring specimen test. (author)

  2. Small Scale Yielding Correction of Constraint Loss in Small Sized Fracture Toughness Test Specimens

    International Nuclear Information System (INIS)

    Kim, Maan Won; Kim, Min Chul; Lee, Bong Sang; Hong, Jun Hwa

    2005-01-01

    Fracture toughness data in the ductile-brittle transition region of ferritic steels show scatter produced by local sampling effects and specimen geometry dependence which results from relaxation in crack tip constraint. The ASTM E1921 provides a standard test method to define the median toughness temperature curve, so called Master Curve, for the material corresponding to a 1T crack front length and also defines a reference temperature, T 0 , at which median toughness value is 100 MPam for a 1T size specimen. The ASTM E1921 procedures assume that high constraint, small scaling yielding (SSY) conditions prevail at fracture along the crack front. Violation of the SSY assumption occurs most often during tests of smaller specimens. Constraint loss in such cases leads to higher toughness values and thus lower T 0 values. When applied to a structure with low constraint geometry, the standard fracture toughness estimates may lead to strongly over-conservative estimates. A lot of efforts have been made to adjust the constraint effect. In this work, we applied a small-scale yielding correction (SSYC) to adjust the constraint loss of 1/3PCVN and PCVN specimens which are relatively smaller than 1T size specimen at the fracture toughness Master Curve test

  3. The influence of specimen size on creep crack growth rate in cross-weld CT specimens cut out from a welded component

    International Nuclear Information System (INIS)

    Andersson, Peder; Segle, Peter; Samuelson, Lars Aa.

    1999-04-01

    A 3D finite element study of creep crack growth in cross-weld CT specimens with material properties of 2.25Cr1Mo at 550 deg C is carried out, where large strain and displacement theory is used. The creep crack growth rate is calculated using a creep ductility based damage model, in which the creep strain rate perpendicular to the crack plane ahead of the crack tip is integrated, considering the multiaxial stress state. The influence of specimen size on creep crack growth rate under constant load is given special attention, but the possibility to transfer results from cross-weld CT specimens to welded high temperature components is also investigated. The creep crack growth rate of a crack in a circumferentially welded pipe is compared with the creep crack growth rate of cross-weld CT specimens of three different sizes, cut out from the pipe. Although the constraint ahead of the crack tip is higher for a larger CT specimen, the creep crack growth rate is higher for a smaller specimen than for a larger one if they are loaded to attain the same stress intensity factor. If the specimens are loaded to the same C* value, however, a more complicated pattern occurs; depending on the material properties of the weldment constituents, the CT specimen with the intermediate size will either yield the highest or the lowest creep crack growth rate

  4. Prediction of fracture toughness based on experiments with sub-size specimens in the brittle and ductile regimes

    Energy Technology Data Exchange (ETDEWEB)

    Mahler, Michael, E-mail: Michael.Mahler@kit.edu; Aktaa, Jarir

    2016-04-15

    For determination of fracture toughness in the brittle regime or ductile fracture in the upper shelf region, special standard specifications are in use e.g. ASTM E399 or ASTM E1820. Due to the rigorous size requirements for specimen testing, it is necessary to use big specimens. To circumvent this problem an approach based on finite element (FE) simulations using the cohesive zone model (CZM) is used. The parameters of the cohesive zone model have been determined using sub-size specimens. With the identified parameters, simulations of standard-size specimens have been performed to successfully predict fracture toughness of standard-size specimens in the brittle and ductile regimes. The objective is to establish small size testing technology for the determination of fracture toughness. - Highlights: • Prediction of fracture toughness on standard-size specimens. • Valid fracture toughness based on sub-size specimens. • Triaxiality dependent cohesive zone model. • Approach works independent on fracture appearance (brittle, ductile).

  5. Effects of aspect ratio and specimen size on uniaxial failure stress of iron green bodies at high strain rates

    Directory of Open Access Journals (Sweden)

    Kuroyanagi Yuki

    2015-01-01

    Full Text Available Powder metallurgy is used for the production of a number of mechanical parts and is an essential production method. These are great advantages such as product cost effectiveness and product uniqueness. In general, however parts created by powder metallurgy have low strength because of low density. In order to increase strength as well as density, new techniques such as high-velocity-compaction (HVC was developed and further investigation has been conducted on improvement of techniques and optimum condition using computer simulation. In this study, the effects of aspect ratio and specimen size of iron green bodies on failure strength of uniaxial compression and failure behavior were examined using a split Hopkinson pressure Bar. The diameters of specimens were 12.5 mm and 25 mm the aspect ratios (thickness/diameter were 0.8 and 1.2.

  6. Development of fatigue life evaluation method using small specimen

    International Nuclear Information System (INIS)

    Nogami, Shuhei; Nishimura, Arata; Wakai, Eichi; Tanigawa, Hiroyasu; Itoh, Takamoto; Hasegawa, Akira

    2013-01-01

    For developing the fatigue life evaluation method using small specimen, the effect of specimen size and shape on the fatigue life of the reduced activation ferritic/martensitic steels (F82H-IEA, F82H-BA07 and JLF-1) was investigated by the fatigue test at room temperature in air using round-bar and hourglass specimens with various specimen sizes (test section diameter: 0.85–10 mm). The round-bar specimen showed no specimen size and no specimen shape effects on the fatigue life, whereas the hourglass specimen showed no specimen size effect and obvious specimen shape effect on it. The shorter fatigue life of the hourglass specimen observed under low strain ranges could be attributed to the shorter micro-crack initiation life induced by the stress concentration dependent on the specimen shape. On the basis of this study, the small round-bar specimen was an acceptable candidate for evaluating the fatigue life using small specimen

  7. The effect of specimen and flaw dimensions on fracture toughness

    International Nuclear Information System (INIS)

    Nevalainen, M.J.

    1997-06-01

    The effect of the specimen size and geometry on fracture toughness has been investigated both by experimental tests and computational analyses. The methods for constraint description, namely T-stress, Q-parameter and Small-Scale Yielding Correction (SSYC) have been compared and applied for various geometries. A statistical treatment for the specimen thickness effect on cleavage fracture toughness has been investigated. Elliptical surface cracks were compared with straight-thickness cracks and a method for crack shape correction was presented. Based on the results, the differences in apparent fracture toughness values obtained from various specimen configurations can be better understood and taken into account

  8. Size Effects on the Strength of Metals

    DEFF Research Database (Denmark)

    Huang, Xiaoxu

    2014-01-01

    The grain size effect and the specimen size effect on the strength of metals are briefly reviewed with respect to their history and current status of research. It is revealed that the fundamental strengthening mechanisms responsible for these two types of size effect are to increase the resistanc...

  9. The effect of specimen and flaw dimensions on fracture toughness

    Energy Technology Data Exchange (ETDEWEB)

    Nevalainen, M.J. [VTT Manufacturing Technology, Espoo (Finland)

    1997-06-01

    The effect of the specimen size and geometry on fracture toughness has been investigated both by experimental tests and computational analyses. The methods for constraint description, namely T-stress, Q-parameter and Small-Scale Yielding Correction (SSYC) have been compared and applied for various geometries. A statistical treatment for the specimen thickness effect on cleavage fracture toughness has been investigated. Elliptical surface cracks were compared with straight-thickness cracks and a method for crack shape correction was presented. Based on the results, the differences in apparent fracture toughness values obtained from various specimen configurations can be better understood and taken into account. 64 refs. The thesis includes also four previous publications by author.

  10. The feasibility of small size specimens for testing of environmentally assisted cracking of irradiated materials and of materials under irradiation in reactor core

    International Nuclear Information System (INIS)

    Toivonen, A.; Moilanen, P.; Pyykkoenen, M.; Taehtinen, S.; Rintamaa, R.; Saario, T.

    1998-01-01

    Environmentally assisted cracking (EAC) of core materials has become an increasingly important issue of downtime and maintenance costs in nuclear power plants. Small size specimens are necessary in stress corrosion testing of irradiated materials because of difficulties in handling high dose rate materials and because of restricted availability of the materials. The drawback of using small size specimens is that in some cases they do not fulfil the requirements of the relevant testing standards. Recently VTT has developed J-R testing with irradiated and non-irradiated sub size 3 PB specimens, both in inert and in LWR environments. Also, a new materials testing system which will enable simultaneous multiple specimen testing both in laboratory conditions and in operating reactor core is under development. The new testing system will utilize Charpy and sub size 3 PB specimens. The feasibility study of the system has been carried out using different materials. Fracture resistance curves of a Cu-Zr-Cr alloy are shown to be independent of the specimen geometry and size, to some extent. Results gained from tests in simulated boiling water reactor (BWR) water are presented for sensitized SIS 2333 stainless steel. The experimental results indicate that the size of the plastic zone or stress triaxiality must be further studied although no significant effect on the environmentally assisted crack growth rate was observed. (orig.)

  11. The feasibility of small size specimens for testing of environmentally assisted cracking of irradiated materials and of materials under irradiation in reactor core

    Energy Technology Data Exchange (ETDEWEB)

    Toivonen, A.; Moilanen, P.; Pyykkoenen, M.; Taehtinen, S.; Rintamaa, R.; Saario, T. [Valtion Teknillinen Tutkimuskeskus, Espoo (Finland)

    1998-11-01

    Environmentally assisted cracking (EAC) of core materials has become an increasingly important issue of downtime and maintenance costs in nuclear power plants. Small size specimens are necessary in stress corrosion testing of irradiated materials because of difficulties in handling high dose rate materials and because of restricted availability of the materials. The drawback of using small size specimens is that in some cases they do not fulfil the requirements of the relevant testing standards. Recently VTT has developed J-R testing with irradiated and non-irradiated sub size 3 PB specimens, both in inert and in LWR environments. Also, a new materials testing system which will enable simultaneous multiple specimen testing both in laboratory conditions and in operating reactor core is under development. The new testing system will utilize Charpy and sub size 3 PB specimens. The feasibility study of the system has been carried out using different materials. Fracture resistance curves of a Cu-Zr-Cr alloy are shown to be independent of the specimen geometry and size, to some extent. Results gained from tests in simulated boiling water reactor (BWR) water are presented for sensitized SIS 2333 stainless steel. The experimental results indicate that the size of the plastic zone or stress triaxiality must be further studied although no significant effect on the environmentally assisted crack growth rate was observed. (orig.)

  12. Tumor Size on Abdominal MRI Versus Pathologic Specimen in Resected Pancreatic Adenocarcinoma: Implications for Radiation Treatment Planning

    Energy Technology Data Exchange (ETDEWEB)

    Hall, William A., E-mail: whall4@emory.edu [Department of Radiation Oncology, Emory University, Atlanta, Georgia (United States); Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Mikell, John L. [Department of Radiation Oncology, Emory University, Atlanta, Georgia (United States); Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Mittal, Pardeep [Department of Radiology, Emory University, Atlanta, Georgia (United States); Colbert, Lauren [Department of Radiation Oncology, Emory University, Atlanta, Georgia (United States); Prabhu, Roshan S. [Department of Radiation Oncology, Emory University, Atlanta, Georgia (United States); Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Kooby, David A. [Department of Surgery, Emory University, Atlanta, Georgia (United States); Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Nickleach, Dana [Biostatistics and Bioinformatics Shared Resource, Emory University, Atlanta, Georgia (United States); Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Hanley, Krisztina [Department of Pathology, Emory University, Atlanta, Georgia (United States); Sarmiento, Juan M. [Department of Surgery, Emory University, Atlanta, Georgia (United States); Ali, Arif N.; Landry, Jerome C. [Department of Radiation Oncology, Emory University, Atlanta, Georgia (United States); Winship Cancer Institute, Emory University, Atlanta, Georgia (United States)

    2013-05-01

    Purpose: We assessed the accuracy of abdominal magnetic resonance imaging (MRI) for determining tumor size by comparing the preoperative contrast-enhanced T1-weighted gradient echo (3-dimensional [3D] volumetric interpolated breath-hold [VIBE]) MRI tumor size with pathologic specimen size. Methods and Materials: The records of 92 patients who had both preoperative contrast-enhanced 3D VIBE MRI images and detailed pathologic specimen measurements were available for review. Primary tumor size from the MRI was independently measured by a single diagnostic radiologist (P.M.) who was blinded to the pathology reports. Pathologic tumor measurements from gross specimens were obtained from the pathology reports. The maximum dimensions of tumor measured in any plane on the MRI and the gross specimen were compared. The median difference between the pathology sample and the MRI measurements was calculated. A paired t test was conducted to test for differences between the MRI and pathology measurements. The Pearson correlation coefficient was used to measure the association of disparity between the MRI and pathology sizes with the pathology size. Disparities relative to pathology size were also examined and tested for significance using a 1-sample t test. Results: The median patient age was 64.5 years. The primary site was pancreatic head in 81 patients, body in 4, and tail in 7. Three patients were American Joint Commission on Cancer stage IA, 7 stage IB, 21 stage IIA, 58 stage IIB, and 3 stage III. The 3D VIBE MRI underestimated tumor size by a median difference of 4 mm (range, −34-22 mm). The median largest tumor dimensions on MRI and pathology specimen were 2.65 cm (range, 1.5-9.5 cm) and 3.2 cm (range, 1.3-10 cm), respectively. Conclusions: Contrast-enhanced 3D VIBE MRI underestimates tumor size by 4 mm when compared with pathologic specimen. Advanced abdominal MRI sequences warrant further investigation for radiation therapy planning in pancreatic adenocarcinoma before

  13. Tumor Size on Abdominal MRI Versus Pathologic Specimen in Resected Pancreatic Adenocarcinoma: Implications for Radiation Treatment Planning

    International Nuclear Information System (INIS)

    Hall, William A.; Mikell, John L.; Mittal, Pardeep; Colbert, Lauren; Prabhu, Roshan S.; Kooby, David A.; Nickleach, Dana; Hanley, Krisztina; Sarmiento, Juan M.; Ali, Arif N.; Landry, Jerome C.

    2013-01-01

    Purpose: We assessed the accuracy of abdominal magnetic resonance imaging (MRI) for determining tumor size by comparing the preoperative contrast-enhanced T1-weighted gradient echo (3-dimensional [3D] volumetric interpolated breath-hold [VIBE]) MRI tumor size with pathologic specimen size. Methods and Materials: The records of 92 patients who had both preoperative contrast-enhanced 3D VIBE MRI images and detailed pathologic specimen measurements were available for review. Primary tumor size from the MRI was independently measured by a single diagnostic radiologist (P.M.) who was blinded to the pathology reports. Pathologic tumor measurements from gross specimens were obtained from the pathology reports. The maximum dimensions of tumor measured in any plane on the MRI and the gross specimen were compared. The median difference between the pathology sample and the MRI measurements was calculated. A paired t test was conducted to test for differences between the MRI and pathology measurements. The Pearson correlation coefficient was used to measure the association of disparity between the MRI and pathology sizes with the pathology size. Disparities relative to pathology size were also examined and tested for significance using a 1-sample t test. Results: The median patient age was 64.5 years. The primary site was pancreatic head in 81 patients, body in 4, and tail in 7. Three patients were American Joint Commission on Cancer stage IA, 7 stage IB, 21 stage IIA, 58 stage IIB, and 3 stage III. The 3D VIBE MRI underestimated tumor size by a median difference of 4 mm (range, −34-22 mm). The median largest tumor dimensions on MRI and pathology specimen were 2.65 cm (range, 1.5-9.5 cm) and 3.2 cm (range, 1.3-10 cm), respectively. Conclusions: Contrast-enhanced 3D VIBE MRI underestimates tumor size by 4 mm when compared with pathologic specimen. Advanced abdominal MRI sequences warrant further investigation for radiation therapy planning in pancreatic adenocarcinoma before

  14. Progress report on irradiation experiment on small size specimens in high temperature flux module

    Energy Technology Data Exchange (ETDEWEB)

    Ramesh, M.; Jacquet, P.; Chaouadi, R.

    2011-02-15

    This report describes the progress made in IFREC/DEMO Research and Development Program during the year 2010 at SCK/CEN. This task is part of demonstrating the possibility to irradiate small specimens in the HFTM modules that will be used in DEMO. Different small specimens of three candidate materials of DEMO fusion reactor will be irradiated with the objective of validating the specimen geometry and size to reliably characterize the mechanical properties of unirradiated and in future of irradiated materials.

  15. Reduction of Specimen Size for the Full Simultaneous Characterization of Thermoelectric Performance

    Science.gov (United States)

    Vasilevskiy, D.; Simard, J.-M.; Masut, R. A.; Turenne, S.

    2017-05-01

    The successful implementation of thermoelectric (TE) materials for waste heat recovery depends strongly on our ability to increase their performance. This challenge continues to generate a renewed interest in novel high TE performance compounds. The technological difficulties in producing homogeneous ingots of new compounds or alloys with regular shape and a size sufficiently large to prepare several samples that are usually needed for a separate measurement of all TE parameters are well known. It creates a situation whereby material performance could be critically over- or under-evaluated at the first stages of the research process of a new material. Both cases would equally lead to negative consequences. Thus, minimizing the specimen size yet keeping it adequate for accurate material characterization becomes extremely important. In this work we report the experimental validation of reliable simultaneous measurements of the four most relevant TE parameters on a single bismuth telluride alloy based specimen of 4 mm × 4 mm × 1.4 mm in size. This translates in roughly 140 mg in weight for one of the heaviest TE materials, as was used in this study, and coefficient, electrical resistivity, thermal conductivity and the figure of merit were simultaneously assessed from 300 K to 440 K with increments of 20 K, 15 K, 10 K, 5 K, and 1 K. Our choice of a well-known homogeneous material has been made to increase measurement reliability and accuracy, but the results are expected to be valid for the full TE characterization of any unknown material. These results show a way to significantly decrease specimen sizes which has the potential to accelerate investigation of novel TE materials for large scale waste heat recovery.

  16. Size effects in ductile cellular solids. Part I : modeling

    NARCIS (Netherlands)

    Onck, P.R.; Andrews, E.W.; Gibson, L.J.

    2001-01-01

    In the mechanical testing of metallic foams, an important issue is the effect of the specimen size, relative to the cell size, on the measured properties. Here we analyze size effects for the modulus and strength of regular, hexagonal honeycombs under uniaxial and shear loadings. Size effects for

  17. Effect of specimen size on the upper shelf energy of ferritic steels

    International Nuclear Information System (INIS)

    Kumar, A.S.

    1990-01-01

    A methodology is proposed that can be used to predict the upper shelf energy (USE) of ferritic steels based on subsize specimen data. The proposed methodology utilizes the partitioning of the USE into energies required for crack initiation and crack propagation. Notched-only Charpy specimens are used in conjunction with precracked specimens to separate the two components. An unirradiated ferritic steel, HT-9, was used to demonstrate the validity of the methodology. Unlike previous correlations that were limited in their applicability to either highly ductile or brittle material, the proposed methodology is expected to be applicable over a wide range of ductility and to be particularly useful for materials that harden significantly during irradiation

  18. Development of fatigue life evaluation technique using miniature specimen

    International Nuclear Information System (INIS)

    Nogami, Shuhei; Nishimura, Arata; Fujiwara, Masaharu; Hisaka, Tomoaki

    2012-01-01

    To develop the fatigue life evaluation technique using miniature specimen, the investigation of the effect of specimen size and specimen shape on the fatigue life and the development of the fatigue testing machine, especially the extensometer, were carried out. The effect of specimen size on the fatigue life was almost negligible for the round-bar specimens. The shorter fatigue life at relatively low strain range conditions for the hourglass specimen that the standard specimen were observed. Therefore the miniature round-bar specimen was considered to be adequate for the fatigue life evaluation using small specimen. Several types of the extensometer system using a strain gauge and a laser has been developed for realizing the fatigue test of the miniature round-bar specimen at high temperature in vacuum. (author)

  19. Investigation of smooth specimen scc test procedures; variations in environment, specimen size, stressing frame, and stress state. [for high strength aluminum alloys

    Science.gov (United States)

    Lifka, B. W.; Sprowls, D. O.; Kelsey, R. A.

    1975-01-01

    The variables studied in the stress-corrosion cracking performance of high strength aluminum alloys were: (1) corrosiveness of the environment, (2) specimen size and stiffness of the stressing system, (3) interpretation of transgranular cracking, and (4) interaction of the state of stress and specimen orientation in a product with an anisotropic grain structure. It was shown that the probability of failure and time to fracture for a specimen loaded in direct tension are influenced by corrosion pattern, the stressing assembly stiffness, and the notch tensile strength of the alloy. Results demonstrate that the combination of a normal tension stress and a shear stress acting on the plane of maximum susceptibility in a product with a highly directional grain cause the greatest tendency for stress-corrosion cracking.

  20. The feasibility of prefatigued sub size specimens to fracture mechanical studies in inert and in reactor environments

    International Nuclear Information System (INIS)

    Toivonen, A.; Moilanen, P.; Taehtinen, S.; Aaltonen, P.; Wallin, K.

    1998-01-01

    The feasibility of sub size specimens to fracture mechanical tests in inert and in reactor environment is studied in this paper. The need for using sub size specimens has arised from the need to study highly irradiated materials as well as to study localised stress corrosion cracking, i.e. stress corrosion cracking in very narrow heat affected zones for example in welded thin walled pipes. This paper focuses on the effects of high J-integral values on ductile tearing and on environmentally assisted crack growth rate. The main focus is on the stress corrosion tests. The subject is approached first by theoretical discussion. The experimental study consists of J-R tests in air and of slow J-R tests in simulated boiling water reactor (BWR) environment. In most cases the tests were continued until the J-integral level was significantly above the maximum allowable J values for ductile fracture toughness characterisation prescribed in test standards. The results indicate that the measurement capacity of the specimens depends on the specimen dimensions in J-R tests in air, as could be expected. The measurement capacity limitations are not necessarily important in stress corrosion testing as the environmentally assisted crack growth rate can be measured even without exceeding the J-integral limits given in J-R standards. The theoretical and experimental studies indicate that stress corrosion studies are not limited to linear elastic fracture mechanics approach, but elastic plastic fracture mechanics is applicable as well. (author)

  1. Analytical modeling of the effect of crack depth, specimen size, and biaxial stress on the fracture toughness of reactor vessel steels

    International Nuclear Information System (INIS)

    Chao, Yuh-Jin

    1995-01-01

    Fracture, toughness values for A533-B reactor pressure vessel (RPV) steel obtained from test programs at Oak Ridge National Laboratory (ORNL) and University of Kansas (KU) are interpreted using the J-A 2 analytical model. The analytical model is based on the critical stress concept and takes into consideration the constraint effect using the second parameter A 2 in addition to the generally accepted first parameter J which represents the loading level. It is demonstrated that with the constraint level included in the model effects of crack depth (shallow vs deep), specimen size (small vs. large), and loading type (uniaxial vs biaxial) on the fracture toughness from the test programs can be interpreted and predicted

  2. Results of UT training for defect detection and sizing technique using specimens with fatigue crack and SCC

    International Nuclear Information System (INIS)

    Yoneyama, H.; Yamaguchi, A.; Sugibayashi, T.

    2005-01-01

    At the importance increase of UT (ultrasonic testing) with the application of rules on fitness-for-service for nuclear power plants, JAPEIC (Japan power engineering and inspection corporation) started education training for defect detection and sizing technique. Weld joints specimen with EDM (Electro-Discharged Machining) notches, fatigue cracks and intergranular stress corrosion cracks were tested and practiced repeatedly based on a modified ultrasonic method and the defect size measuring accuracy of the trainees was surely improved. Results of the blind test confirmed effectiveness of education training. (T. Tanaka)

  3. Ductile fracture toughness of heavy section pressure vessel steel plate. A specimen-size study of ASTM A 533 steels

    International Nuclear Information System (INIS)

    Williams, J.A.

    1979-09-01

    The ductile fracture toughness, J/sub Ic/, of ASTM A 533, Grade B, Class 1 and ASTM A 533, heat treated to simulate irradiation, was determined for 10- to 100-mm thick compact specimens. The toughness at maximum specimen load was also measured to determine the conservatism of J/sub Ic/. The toughness of ASTM A 533, Grade B, Class 1 steel was 349 kJ/m 2 and at the equivalent upper shelf temperature, the heat treated material exhibited 87 kJ/m 2 . The maximum load fracture toughness was found to be linearly proportional to specimen size, and only specimens which failed to meet ASTM size criteria exhibited maximum load toughness less than J/sub Ic/

  4. 2015 Accomplishments-Tritium aging studies on stainless steel. Effects of hydrogen isotopes, crack orientation, and specimen geometry on fracture toughness

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, Michael J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-01-01

    This study reports on the effects of hydrogen isotopes, crack orientation, and specimen geometry on the fracture toughness of stainless steels. Fracture toughness variability was investigated for Type 21-6-9 stainless steel using the 7K0004 forging. Fracture toughness specimens were cut from the forging in two different geometric configurations: arc shape and disc shape. The fracture toughness properties were measured at ambient temperature before and after exposure to hydrogen gas and compared to prior studies. There are three main conclusions that can be drawn from the results. First, the fracture toughness properties of actual reservoir forgings and contemporary heats of steel are much higher than those measured in earlier studies that used heats of steel from the 1980s and 1990s and forward extruded forgings which were designed to simulate reservoir microstructures. This is true for as-forged heats as well as forged heats exposed to hydrogen gas. Secondly, the study confirms the well-known observation that cracks oriented parallel to the forging grain flow will propagate easier than those oriented perpendicular to the grain flow. However, what was not known, but is shown here, is that this effect is more pronounced, particularly after hydrogen exposures, when the forging is given a larger upset. In brick forgings, which have a relatively low amount of upset, the fracture toughness variation with specimen orientation is less than 5%; whereas, in cup forgings, the fracture toughness is about 20% lower than that forging to show how specimen geometry affects fracture toughness values. The American Society for Testing Materials (ASTM) specifies minimum specimen section sizes for valid fracture toughness values. However, sub-size specimens have long been used to study tritium effects because of the physical limitation of diffusing hydrogen isotopes into stainless steel at mild temperatures so as to not disturb the underlying forged microstructure. This study shows

  5. Evaluation of Specimen Geometric Effect for Laser Flash Thermal Diffusivity Test

    International Nuclear Information System (INIS)

    Park, Dae Gyu; Kim, Hee Moon; Song, Woong Sub; Baik, Seung Je; Ryu, Woo Seok; Ahn, Sang Bok; Joo, Young Sun

    2012-01-01

    KAERI(Korea Atomic Energy Research Institute) is developing a new type of nuclear reactor, the so called 'SMART' (System Integrated Modular Advanced Reactor) reactor. Alloy 690 was selected as the candidate material for the heat exchanger tube of of SMART's steam generator. The SMART R and D is now facing the stage of engineering verification and standard design approval for application of DEMO reactors. Therefore, the material performance under the relevant environment needs to be evaluated. The one of the important material performance issues is thermal conductivity, which the engineering database is necessary for the steam generator design. However, the neutron post irradiation characteristics of alloy 690 are little known. As a result, a PIE (Post Irradiation Examination) of the thermal properties have been plan for a 4 times, so called base line test, 1 st irradiation test, 2 nd and 3 rd irradiation test. But there is some constraint to perform thermal diffusivity test owing to test specimen. Originally thermal diffusivity test are planed using disk shape with 9 mm diameter and 1 mm thick specimen. Due to mismatch of neutron irradiation schedule, thermal diffusivity will be tested by different shape and size specimens at 1 st irradiation test. Therefore, verification of geometric and size effect are necessary for test specimen in order to achieve accurate test results

  6. Development of specimen size and test rate effects on the J-integral upper transition behavior of A533B steel

    International Nuclear Information System (INIS)

    Joyce, James A.

    1988-01-01

    During the past three years a test method has been developed for dynamic testing of fracture mechanics specimens which is specifically designed for application to the upper transition temperature range. The method uses drop tower loading rates of 2.5 m/sec and obtains a J IC or a J-R curve using an analytical key curve approach verified by initial and final crack length measurements obtained from the fracture surface. A J-R curve is obtained from each specimen and contains crack growth corrections so that it is directly comparable with static results obtained in accordance with the ASTM E1152 J-R curve test method. The test procedure has been applied to A106 steel, A533B steel and US Navy HY80 and HY100 steels at temperatures from -200F to 150F. Standard 1T three point bend specimens were used for the A533B and the HY100 steel. Static test results have shown that the J at cleavage initiation (which is presently an unstandardized quantity) is specimen a/W independent throughout the ductile to brittle transition but of course demonstrates considerable statistical scatter in the vicinity of the ductile upper shelf. Dynamic J-R tests have shown an increase in J IC with test rate for most, but not for all, materials. Separation of J into elastic and plastic components shows that the elastic J component increases with test rate in a fashion consistent with the materials tensile sensitivity to test rate but the plastic J component decreases with test rate - an apparent visco-plastic phenomena. For A106 steel the plastic J decrease exceeds the elastic J increase and the upper shelf toughness falls - while the other materials have demonstrated a relatively larger increase in the elastic J component and a smaller decrease in the plastic J component giving an overall increase in upper shelf toughness. Separation of the J integral into elastic and plastic components has demonstrated that J EL is specimen scale and geometry dependent while J PL is relatively scale and geometry

  7. Notch effects in uniaxial tension specimens

    International Nuclear Information System (INIS)

    Delph, T.J.

    1979-03-01

    Results of a literature survey on the effect of notches on the time-dependent failure of uniaxial tension specimens at elevated temperatures are presented. Particular attention is paid to the failure of notched specimens containing weldments

  8. Size effects in the mechanical behavior of cellular materials

    NARCIS (Netherlands)

    Tekoglu, C; Onck, PR

    Effective mechanical properties of cellular materials depend strongly on the specimen size to the cell size ratio. Experimental studies performed on aluminium foams show that under uniaxial compression, the stiffness of these materials falls below the corresponding bulk value, when the ratio of the

  9. Development of high time-resolution laser flash equipment for thermal diffusivity measurements using miniature-size specimens

    International Nuclear Information System (INIS)

    Shikama, Tatsuo; Namba, Chusei; Kosuda, Michinori; Maeda, Yukio.

    1994-01-01

    For measurements of thermal diffusivity of miniature-size specimens heavily irradiated by neutrons, a new Q-switched laser-flash instrument was developed. In the present instrument the time-resolution was improved to 0.1 ms by using a laser-pulse width of 25 ns. The realization of high time-resolution made it possible to measure the thermal diffusivity of thin specimens. It is expected that copper of 0.7 mm thick, and SUS 304 of 0.1 mm could be used for the measurements. In case of ATJ graphite, 0.5 mm thick specimen could be used for the reliable measurement in the temperature range of 300-1300 K. (author)

  10. Recent improvements in size effects correlations for DBTT and upper shelf energy of ferritic steels

    International Nuclear Information System (INIS)

    Kumar, A.S.; Louden, B.S.; Garner, F.A.; Hamilton, M.L.

    1992-01-01

    Currently available correlations for the effects of specimen size on the USE were developed for relatively ductile steels and will not serve as well when the steels become embrittled. Size effects correlations were developed recently for the impact properties of less ductile HT9 to be applied to other initially more ductile steels as they lose their ductility during irradiation. These new correlations successfully predict the ductile brittle transition temperature (DBTT) and the upper shelf energy (USE) of full size Charpy specimens based on subsize specimen data. The new DBTT and the USE correlations were tested against published experimental data on other ferritic steels and shown to perform successfully at lower USE particularly when both precracked and notched only specimens were employed

  11. Prediction of primary breast cancer size and T-stage using micro-computed tomography in lumpectomy specimens

    Directory of Open Access Journals (Sweden)

    Wafa M Sarraj

    2015-01-01

    Full Text Available Background: Histopathology is the only accepted method to measure and stage the breast tumor size. However, there is a need to find another method to measure and stage the tumor size when the pathological assessment is not available. Micro-computed tomography. (micro-CT has the ability to measure tumor in three dimensions in an intact lumpectomy specimen. In this study, we aimed to determine the accuracy of micro-CT to measure and stage the primary tumor size in breast lumpectomy specimens, as compared to the histopathology. Materials and Methods: Seventy-two women who underwent lumpectomy surgery at the Massachusetts General Hospital Department of Surgery from June 2011 to September 2011, and from August 2013 to December 2013 participated in this study. The lumpectomy specimens were scanned using micro-CT followed by routine pathological processing. The maximum dimension of the invasive breast tumor was obtained from the micro-CT image and was compared to the corresponding pathology report for each subject. Results: The invasive tumor size measurement by micro-CT was underestimated in 24. cases. (33%, overestimated in 37. cases. (51%, and matched it exactly in 11. cases. (15% compared to the histopathology measurement for all the cases. However, micro-CT T.stage classification differed from histopathology in only 11. (15.2% with 6. cases. (8.3% classified as a higher stage by micro-CT, and 5. cases. (6.9% classified as lower compared to histopathology. In addition, micro-CT demonstrated a statically significant strong agreement (κ =0.6, P < 0.05 with pathological tumor size and staging for invasive ductal carcinoma. (IDC group. In contrast, there was no agreement. (κ = .2, P = 0.67 between micro-CT and pathology in estimating and staging tumor size for invasive lobular carcinoma. (ILC group. This could be explained by a small sample size. (7 for ILC group. Conclusions: Micro-CT is a promising modality for measuring and staging the IDC.

  12. Effect of a new specimen size on fatigue crack growth behavior in thick-walled pressure vessels

    International Nuclear Information System (INIS)

    Shariati, Mahmoud; Mohammadi, Ehsan; Masoudi Nejad, Reza

    2017-01-01

    Fatigue crack growth in thick-walled pressure vessels is an important factor affecting their fracture. Predicting the path of fatigue crack growth in a pressure vessel is the main issue discussed in fracture mechanics. The objective of this paper is to design a new geometrical specimen in fatigue to define the behavior of semi-elliptical crack growth in thick-walled pressure vessels. In the present work, the importance of the behavior of fatigue crack in test specimen and real conditions in thick-walled pressure vessels is investigated. The results of fatigue loading on the new specimen are compared with the results of fatigue loading in a cylindrical pressure vessel and a standard specimen. Numerical and experimental methods are used to investigate the behavior of fatigue crack growth in the new specimen. For this purpose, a three-dimensional boundary element method is used for fatigue crack growth under stress field. The modified Paris model is used to estimate fatigue crack growth rates. In order to verify the numerical results, fatigue test is carried out on a couple of specimens with a new geometry made of ck45. A comparison between experimental and numerical results has shown good agreement. - Highlights: • This paper provides a new specimen to define the behavior of fatigue crack growth. • We estimate the behavior of fatigue crack growth in specimen and pressure vessel. • A 3D finite element model has been applied to estimate the fatigue life. • We compare the results of fatigue loading for cylindrical vessel and specimens. • Comparison between experimental and numerical results has shown a good agreement.

  13. Fracture toughness evaluation of small notched specimen in consideration of notch effect and loading rate

    International Nuclear Information System (INIS)

    Lee, Baik Woo; Kwon, Dong Il; Jang, Jae Il

    2000-01-01

    Notch effect and loading rate dependency on fracture toughness were considered when evaluating fracture toughness of small notched specimens using the instrumented impact test. Notch effect was analyzed into stress redistribution effect and stress relaxation with a viewpoint of stress triaxiality. Stress redistribution effect was corrected by introducing effective crack length, which was the sum of actual crack length and plastic zone size. Stress relaxation effect was also corrected using elastic stress concentration factor, which would decrease if plastic deformation occurred. As a result, corrected fracture toughness of the notched specimen was very consistent with the reference fracture toughness obtained using precracked specimen. In addition, limiting notch root radius, below which fracture toughness was independent of notch radius, was observed and discussed. Loading rate dependency on fracture toughness, which was obtained from the static three point bending test and the instrumented impact test, was also discussed with stress field in plastic zone ahead of a notch and fracture based on stress control mechanism. (author)

  14. On size effects in fracture

    International Nuclear Information System (INIS)

    Sinclair, G.B.

    1985-01-01

    This paper discusses the dependence of fracture stress on size. This conclusion is based on classical energy arguments. For an in-plane scaled specimen pair, the larger the specimen the smaller the fracture stress. In contrast the same theory gives a different dependence for out-of-plane specimen and the dependence involves plane stress, strain, fracture stresses and Poisson's ratio. The objective of this paper is to examine how well these predictions are actually complied with

  15. Mean stress sensitivity of ductile iron with respect to technological and statistical size effect considering defects

    Directory of Open Access Journals (Sweden)

    Kainzinger Paul

    2014-06-01

    Full Text Available Specimens of two sizes have been taken from two sampling locations within a wind turbine hub made of nodular cast iron (EN-GJS-400-18-LT for constant amplitude fatigue testing. The sampling positions exhibit varying cooling conditions, resulting in different microstructures. Fatigue tests have been carried out at R-ratios of R = −1 and R = 0. The coarse microstructure as well as the larger specimens yielded in lower fatigue strengths. No effect of the microstructure or the specimen size on the mean stress sensitivity has been found. Fractographic analysis of the fractured specimen's surface revealed micro-shrinkages to be the source of crack initiation for all specimens. Micro-shrinkage size increases from fine to coarse microstructure and with increasing specimen size. The El-Haddad equation using the √area parameter was used to describe the fatigue limit. The results were in good agreement with the experiments.

  16. High temperature corrosion behavior of different grain size specimens of 2.25 Cr-1 Mo steel in SO2+O2 environment

    International Nuclear Information System (INIS)

    Ghosh, D.; Mitra, S.K.

    2011-01-01

    The investigation is primarily aimed at the high temperature corrosion behavior of different grain sizes of 2.25 Cr-1 Mo steel at SO 2 +O 2 (mixed oxidation and sulfidation). The various grain sizes (18 μm,26 μm, 48 μm, and 72 μm) are obtained by different annealing treatment. Isothermal corrosion studies are carried out in different grain size specimens at 973K for 8 hours. The corrosion growth rate and the reaction kinetics are studied by weight gain method. The external scales of the post corroded specimen are studied in Scanning Electron Microscope (SEM) to examine the corrosion products morphology on the scale. X-ray mapping analysis of the different elements (Fe, O, Cr and S) is carried out by Energy Dispersive Spectroscopy (EDS) attached with SEM. The X-ray Diffraction Analysis (XRD) is also carried out to identify the corrosion products in the external scale. Finally, it is concluded that that the corrosion rate of 2.25 Cr-1 Mo steel strongly depend on grain sizes of the specimens. The corrosion rate increases with the decreases of grain size. The finer grain (18 μm) show higher corrosion rate than the coarse grains (72 μm). The weight gain kinetics follows the parabolic growth rate which further indicates that the corrosion process is diffusion controlled. The scale analysis shows the thicker scale and extensive scale cracking and spallations in case of finer grain size specimen (18 μm), whereas the coarse grain specimen (72 μm) shows compact and adherent layer. The XRD analysis shows that the corrosion products consist of mixtures of iron oxides( Fe 3 O 4 and Fe 2 O 3 ) and iron sulfides (FeS). The details mechanism of the corrosion is discussed to explain the difference in corrosion rate for different grain sizes. (author)

  17. Size effect in tension perpendicular to the grain

    DEFF Research Database (Denmark)

    Pedersen, Martin Bo Uhre; Clorius, Christian Odin; Damkilde, Lars

    1999-01-01

    The strength in tension perpendicular to the grain is known to decrease with an increase in the stressed volume. Usually this size effect is explained on a stochastic basis, that is an explanation relying on an increased probability of encountering a strength reducing flaw when the volume...... of the material under stress is increased. This paper presents a small experimental investigation on specimens with well defined structural orientation of the material. The experiments exhibit a larger size effect than expected and furthermore the data and the nature of the failures encountered suggest...... that the size effect can be explained on a deterministic basis. Arguments for such a simple deterministic explanation of size effect is found in finite element modelling using the orthotropic stiffness characteristics in the transverse plane of wood....

  18. Influence of specimen size/type on the fracture toughness of five irradiated RPV materials

    International Nuclear Information System (INIS)

    Sokolov, Mikhail A; Lucon, Enrico

    2015-01-01

    The Heavy-Section Steel Irradiation (HSSI) Program had previously irradiated five reactor pressure vessel (RPV) steels/welds at fast neutron fluxes of about 4 to 8 x 10 11 n/cm 2 /s (>1 MeV) to fluences from 0.5 to 3.4 10 19 n/cm 2 and at 288 °C. The unirradiated fracture toughness tests were performed by Oak Ridge National Laboratory with 12.7-mm and 25.4-mm thick (0.5T and 1T) compact specimens, while the HSSI Program provided tensile and 5 x 10-mm three-point bend specimens to SCK-CEN for irradiation in the in-pile section of the Belgian Reactor BR2 at fluxes > 10 13 n/cm 2 /s and subsequent testing by SCK-CEN. The BR2 irradiations were conducted at about 2 and 4 x 10 13 n/cm 2 /s with irradiation temperature between 295 °C and 300 °C (water temperature), and to fluences between 6 and 10 x 10 19 n/cm 2 . The irradiation-induced shifts of the Master Curve reference temperatures, ΔT 0 , for most of the materials deviated from the embrittlement correlations much more than expected, motivating the testing of 5 x 10-mm three-point bend specimens of all five materials in the unirradiated condition to eliminate specimen size and geometry as a variable. Tests of the unirradiated small bend specimens resulted in Master Curve reference temperatures, ΔT 0 , 25 °C to 53 °C lower than those from the larger compact specimens, meaning that the irradiation-induced reference temperature shifts, ΔT 0 , were larger than the initial measurements, resulting in much improved agreement between the measured and predicted fracture toughness shifts.

  19. An experimental assessment of the size effects on the strength and ductility of freestanding copper films under macroscopically homogenous deformation

    Science.gov (United States)

    Chauhan, Shakti Singh

    Metallic interconnects and circuitry has been experiencing excessive deformation beyond their elastic limits in many applications, ranging from micro-electromechanical systems (MEMS) to flexible electronics. These broad applications are creating needs to understand the extent of strength and ductility of freestanding metallic films at scales approaching the micron and sub micron range. This work aims to elucidate the effects of microstructural constraint as well as geometric dimensional constraint on the strength and ductility of freestanding Cu films under uniaxial tension. Two types of films are tested (i) high purity rolled films of 12.5-100microm thickness and average grain sizes of 11-47microm and (ii) electroplated films of 2-50 microm thickness and average grain sizes of 1.8-5microm. Several experimental tools including residual electrical resistivity measurements, surface strain measurements and surface roughness measurements are employed to highlight the underlying deformation mechanisms leading to the observed size effects. With respect to the strength of the specimens, we find that the nature and magnitude of thickness effects is very sensitive to the average grain size. In all cases, coupled thickness and grain size effects were observed. This study shows that this observed coupling, unique to the case of freestanding specimen, arises because the observed size effects are an outcome of the size dependence of two fundamental microstructural parameters i.e. volume fraction of surface grains and grain boundary area per unit specimen volume. For films having thickness and grain sizes greater than 5microm, thickness dependent weakening is observed for a constant grain size. Reducing thickness results in an increase in the volume fraction of grains exposed to the free surface as well as a reduction in the grain boundary area per unit specimen volume. The former effect leads to a reduction in the effective microstructural constraint on the intragranular

  20. Notch size effects on high cycle fatigue limit stress of Udimet 720

    International Nuclear Information System (INIS)

    Ren Weiju; Nicholas, Theodore

    2003-01-01

    Notch size effects on the high cycle fatigue (HCF) limit stress of Ni-base superalloy Udimet 720 were investigated on cylindrical specimens with three notch sizes of the same stress concentration factor K t =2.74. The HCF limit stress corresponding to a life of 10 6 cycles was experimentally determined at a stress ratio of 0.1 and a frequency of 25 Hz at room temperature. The stresses were calculated using finite element analysis (FEA) and the specimens analyzed using scanning electron microscopy (SEM). Test results show that at the same K t value, notch size can slightly affect the HCF limit stress of U720 when notch root plasticity occurs. FEA and SEM results reveal that the notch size effects are influenced by a complicated combination of the stress and plastic strain fields at the notch tip, the nominal stress, and the effects of prior plastic deformation on fatigue crack initiation

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

    International Nuclear Information System (INIS)

    Sokolov, M.A.; McCabe, D.E.; Nanstad, R.K.; Davidov, Y.A.

    1997-01-01

    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 K Ic 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 K k 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 K Jc 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

  2. The Effect of Specimen Size on the Results of Concrete Adiabatic Temperature Rise Test with Commercially Available Equipment

    Directory of Open Access Journals (Sweden)

    Byung Jae Lee

    2014-12-01

    Full Text Available In this study, adiabatic temperature rise tests depending on binder type and adiabatic specimen volume were performed, and the maximum adiabatic temperature rises and the reaction factors for each mix proportion were analyzed and suggested. The results indicated that the early strength low heat blended cement mixture had the lowest maximum adiabatic temperature rise (Q∞ and the ternary blended cement mixture had the lowest reaction factor (r. Also, Q and r varied depending on the adiabatic specimen volume even when the tests were conducted with a calorimeter, which satisfies the recommendations for adiabatic conditions. Test results show a correlation: the measurements from the 50 L specimens were consistently higher than those from the 6 L specimens. However, the Q∞ and r values of the 30 L specimen were similar to those of the 50 L specimen. Based on the above correlation, the adiabatic temperature rise of the 50 L specimen could be predicted using the results of the 6 L and 30 L specimens. Therefore, it is thought that this correlation can be used for on-site concrete quality control and basic research.

  3. The Effect of Specimen Size on the Results of Concrete Adiabatic Temperature Rise Test with Commercially Available Equipment.

    Science.gov (United States)

    Lee, Byung Jae; Bang, Jin Wook; Shin, Kyung Joon; Kim, Yun Yong

    2014-12-08

    In this study, adiabatic temperature rise tests depending on binder type and adiabatic specimen volume were performed, and the maximum adiabatic temperature rises and the reaction factors for each mix proportion were analyzed and suggested. The results indicated that the early strength low heat blended cement mixture had the lowest maximum adiabatic temperature rise ( Q ∞ ) and the ternary blended cement mixture had the lowest reaction factor ( r ). Also, Q and r varied depending on the adiabatic specimen volume even when the tests were conducted with a calorimeter, which satisfies the recommendations for adiabatic conditions. Test results show a correlation: the measurements from the 50 L specimens were consistently higher than those from the 6 L specimens. However, the Q ∞ and r values of the 30 L specimen were similar to those of the 50 L specimen. Based on the above correlation, the adiabatic temperature rise of the 50 L specimen could be predicted using the results of the 6 L and 30 L specimens. Therefore, it is thought that this correlation can be used for on-site concrete quality control and basic research.

  4. On impact testing of subsize Charpy V-notch type specimens

    International Nuclear Information System (INIS)

    Mikhail, A.S.; Nanstad, R.K.

    1994-01-01

    The potential for using subsize specimens to determine the actual properties of reactor pressure vessel steels is receiving increasing attention for improved vessel condition monitoring that could be beneficial for light-water reactor plant-life extension. This potential is made conditional upon, on the one hand, by the possibility of cutting samples of small volume from the internal surface of the pressure vessel for determination of actual properties of the operating pressure vessel. The plant-life extension will require supplemental surveillance data that cannot be provided by the existing surveillance programs. Testing of subsize specimens manufactured from broken halves of previously tested surveillance Charpy V-notch (CVN) specimens offers an attractive means of extending existing surveillance programs. Using subsize CVN type specimens requires the establishment of a specimen geometry that is adequate to obtain a ductile-to-brittle transition curve similar to that obtained from full-size specimens. This requires the development of a correlation of transition temperature and upper-shelf toughness between subsize and full-size specimens. The present study was conducted under the Heavy-Section Steel Irradiation Program. Different published approaches to the use of subsize specimens were analyzed and five different geometries of subsize specimens were selected for testing and evaluation. The specimens were made from several types of pressure vessel steels with a wide range of yield strengths, transition temperatures, and upper-shelf energies (USEs). Effects of specimen dimensions, including depth, angle, and radius of notch have been studied. The correlation of transition temperature determined from different types of subsize specimens and the full-size specimen is presented. A new procedure for transforming data from subsize specimens was developed and is presented

  5. Influence of specimen size/type on the fracture toughness of five irradiated RPV materials

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, Mikhail A [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lucon, Enrico [National Inst. of Standards and Technology (NIST), Boulder, CO (United States)

    2015-01-01

    The Heavy-Section Steel Irradiation (HSSI) Program had previously irradiated five reactor pressure vessel (RPV) steels/welds at fast neutron fluxes of about 4 to 8 x 1011 n/cm2/s (>1 MeV) to fluences from 0.5 to 3.4 1019 n/cm2 and at 288 °C. The unirradiated fracture toughness tests were performed by Oak Ridge National Laboratory with 12.7-mm and 25.4-mm thick (0.5T and 1T) compact specimens, while the HSSI Program provided tensile and 5 x 10-mm three-point bend specimens to SCK-CEN for irradiation in the in-pile section of the Belgian Reactor BR2 at fluxes > 1013 n/cm2/s and subsequent testing by SCK-CEN. The BR2 irradiations were conducted at about 2 and 4 x 1013 n/cm2/s with irradiation temperature between 295 °C and 300 °C (water temperature), and to fluences between 6 and 10 x 1019n/cm2. The irradiation-induced shifts of the Master Curve reference temperatures, ΔT0, for most of the materials deviated from the embrittlement correlations much more than expected, motivating the testing of 5 x 10-mm three-point bend specimens of all five materials in the unirradiated condition to eliminate specimen size and geometry as a variable. Tests of the unirradiated small bend specimens resulted in Master Curve reference temperatures, T0, 25 °C to 53 °C lower than those from the larger compact specimens, meaning that the irradiation-induced reference temperature shifts, ΔT0, were larger than the initial measurements, resulting in much improved agreement between the measured and predicted fracture toughness shifts.

  6. Size effects on failure behaviour of reactor pressure vessel steel and their dependence on deformation inhomogeneity

    International Nuclear Information System (INIS)

    Aktaa, J.; Klotz, M.; Schmitt, R.

    2003-01-01

    The investigation of the size dependence of the material behaviour and particularly of the failure strain is the main objective of the European research project LISSAC (Limit Strains for Severe Accident Conditions). Within our activities in LISSAC, tensile test series with specimens of similar geometry and different sizes are performed. The specimens, cut from the wall of a real reactor vessel, are flat with a central hole, flat with a double edge notch as well as round with a circumferential notch in order to obtain inhomogeneous deformation with high strain gradients, which will be higher in the smaller specimens and might be responsible for size effects. An additional variation of the strain gradient is obtained by varying the central hole radius of the flat specimens, with three different hole geometries being considered: round hole, increased round hole and slot. During the tests optical methods are used for measuring local deformations and partly local strain gradients. The results obtained show a size effect neither on the global nor on the local deformation behaviour, whereas the damage and failure behaviour is influenced significantly by the size of the specimen. On the basis of the surface deformation measurements, finite element calculations are performed to estimate the local failure strains as well as the corresponding strain gradients. A clear dependence of local failure strains on strain gradients is obtained. (author)

  7. Thermal Cycling of Uranium Dioxide - Tungsten Cermet Fuel Specimens

    Energy Technology Data Exchange (ETDEWEB)

    Gripshover, P.J.; Peterson, J.H.

    1969-12-08

    In phase I tungsten clad cermet fuel specimens were thermal cycled, to study the effects of fuel loading, fuel particle size, stablized fuel, duplex coatings, and fabrication techniques on dimensional stability during thermal cycling. In phase II the best combination of the factors studies in phase I were combined in one specimen for evaluation.

  8. Application of subsize specimens in nuclear plant life extension

    International Nuclear Information System (INIS)

    Rosinski, S.T.; Kumar, A.S.; Cannon, N.S.; Hamilton, M.L.

    1993-01-01

    The US Department of Energy is sponsoring a research effort through Sandia National Laboratories and the University of Missouri-Rolla to test a correlation for the upper shelf energy (USE) values obtained from the impact testing of subsize Charpy V-notch specimens to those obtained from the testing of full-size samples. The program involves the impact testing of unirradiated and irradiated full-, half-, and third-size Charpy V-notch specimens. To verify the applicability of the correlation on LWR materials, unirradiated and irradiated full-, half-, and third-size Charpy V-notch specimens of a commercial pressure vessel steel (ASTM A533 Grade B) will be tested. The correlation methodology is based on the partitioning of the USE into crack initiation and crack propagation energies. To accomplish this partition, both precracked and notched-only specimens will be used. Whereas the USE of notched-only specimens is the sum of both crack initiation and crack propagation energies, the USE of precracked specimens reflects only the crack propagation component. The difference in the USE of the two types of specimens represents a measure of the crack initiation energy. Normalizing the values of the crack initiation energy to the fracture volume of the sample produces similar values for the full-, half-, and third-size specimens. In addition, the ratios of the USE and the crack propagation energy are also in agreement for full-, half-, and third-size specimens. These two observations will be used to predict the USE of full-size specimens based on subsize USE data. This paper provides details of the program and presents results obtained from the application of the developed correlation methodology to the impact testing of the unirradiated full-, half-, and third-size A533 Grade B Charpy V-notch specimens

  9. Instrumented impact testing machine with reduced specimen oscillation effects

    International Nuclear Information System (INIS)

    Rintamaa, R.; Rahka, K.; Wallin, K.

    1984-07-01

    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)

  10. Observations of a potential size-effect in experimental determination of the hydraulic properties of fractures

    International Nuclear Information System (INIS)

    Witherspoon, P.A.; Amick, C.H.; Gale, J.E.; Iwai, K.

    1979-05-01

    In several recent investigations, experimental studies on the effect of normal stress on the hydraulic conductivity of a single fracture were made on three rock specimens ranging in cross-sectional area from 0.02 m 2 to over 1.0 m 2 . At the maximum stress levels that could be attained (10 to 20 MPa), minimum values of the fracture hydraulic conductivity were not the same for each rock specimen. These minimum values increased with specimen size, indicating that the determination of fracture conductivity may be significantly influenced by a size effect. The implications of these results are important. Cores collected in the field are normally not larger than 0.15 m in diameter. However, the results of this work suggest that when this size core is used for laboratory investigations, the results may be nonconservative in that fracture permeabilities will be significantly lower than will be found in the field. 6 figures

  11. A Simple Size Effect Model for Tension Perpendicular to the Grain

    DEFF Research Database (Denmark)

    Pedersen, M. U.; Clorius, Christian Odin; Damkilde, Lars

    2003-01-01

    The strength in tension perpendicular to the grain is known to decrease with an increase in the stressed volume. Usually this size effect is explained on a stochastic basis, that is, an explanation relying on the increased probability of encountering a strength reducing flaw when the volume...... of the material under stress is increased. This paper presents an experimental investigation on specimens with a well-defined structural orientation of the material. The experiments exhibit a large size effect and the nature of the failures encountered suggests that the size effect can be explained...... on a deterministic basis. Arguments for such a simple deterministic explanation of size effect is found in finite element modelling, using the orthotropic stiffness characteristics in the transverse plane of wood....

  12. Transition Fracture Toughness Characterization of Eurofer 97 Steel using Pre-Cracked Miniature Multi-notch Bend Bar Specimens

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sokolov, Mikhail A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Linton, Kory D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Clowers, Logan N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Katoh, Yutai [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-11-01

    In this report, we present the feasibility study of using pre-cracked miniature multi-notch bend bar specimens (M4CVN) with a dimension of 45mm (length) x 3.3mm (width) x 1.65mm (thickness) to characterize the transition fracture toughness of Eurofer97 based on the ASTM E1921 Master Curve method. From literature survey results, we did not find any obvious specimen size effects on the measured fracture toughness of unirradiated Eurofer97. Nonetheless, in order to exclude the specimen size effect on the measured fracture toughness of neutron irradiated Eurofer97, comparison of results obtained from larger size specimens with those from smaller size specimens after neutron irradiation is necessary, which is not practical and can be formidably expensive. However, limited literature results indicate that the transition fracture toughness of Eurofer97 obtained from different specimen sizes and geometries followed the similar irradiation embrittlement trend. We then described the newly designed experimental setup to be used for testing neutron irradiated Eurofer97 pre-cracked M4CVN bend bars in the hot cell. We recently used the same setup for testing neutron irradiated F82H pre-cracked miniature multi-notch bend bars with great success. Considering the similarity in materials, specimen types, and the nature of tests between Eurofer97 and F82H, we believe the newly designed experimental setup can be used successfully in fracture toughness testing of Eurofer97 pre-cracked M4CVN specimens.

  13. Effect of Sporosarcina Pasteurii on the strength properties of compressed earth specimens

    International Nuclear Information System (INIS)

    Bernat-Maso, E.; Gil, L.; Escrig, C.; Barbé, J.; Cortés, P.

    2018-01-01

    Microbial biodeposition of calcite induction for improving the performance of rammed earth is a research area that must be analysed in a representative environment. This analysis must consider the compaction force, particle size distribution and curing process as production variables. This paper investigates the effects of adding specific bacteria, Sporosarcina Pasteurii, into compressed earth cubes and the effect of production variables. Uniaxial compressive tests and direct shear tests have been conducted for 80 specimens. The results indicate that calcite precipitation interacts with the drying process of clay/silt resulting in reducing the compressive strength, the apparent cohesion and the friction angle. Finally, bacterial activity, which is more likely in samples cured in a high humidity environment, tends to reduce the dilatancy effect. [es

  14. The effect of specimen thickness on the experimental and finite ...

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    as a fracture parameter and the J-CTOD relation for the determination of critical ... fracture behaviour of EDD (0·06%C) steel sheets with CT specimens and using ... On the other hand, in the predominantly plane stress region, if the toughness value ..... (iii) Hardness measurement – The plastic zone size and shape is also ...

  15. [The effect of disinfectant soaking on dental gypsum model size].

    Science.gov (United States)

    Zhu, Cao-yun; Xu, Yun-wen; Xu, Kan

    2012-12-01

    To study the influence of disinfectant soaking on the dimensional stability of three kinds of dental gypsum model. Three commonly used gypsums ( type III,IV,Vtype) in clinic were used to make 24 specimens for 50 mm×15 mm×10 mm in size. One hour after release, the specimens were placed for 24 h. A digital caliper was used to measure the size of the gypsum model. Distilled water immersion was as used control, glutaraldehyde disinfectant and Metrix CaviCide disinfectant soaking were used for the experimental group. After soaking for 0.5h, the gypsum models were removed and placed for 0.5 h, 1 h, 2 h, 24 h. The size of the models was measured again using the same method. The data was analyzed with SPSS10.0 software package. The initial gypsum model length was (50.07±0.017) mm, (50.048±0.015) mm and (50.027±0.015) mm. After soaking for different times, the size of the model changed little, and the dimensions changed less than 0.01%. The results show that disinfectant soaking has no significant effect on dental model dimensions.

  16. Room temperature fatigue behavior of OFHC copper and CuAl25 specimens of two sizes

    DEFF Research Database (Denmark)

    Singhal, A.; Stubbins, J.F.; Singh, B.N.

    1994-01-01

    requiring an understanding of their fatigue behavior.This paper describes the room temperature fatigue behavior of unirradiated OFHC (oxygen-free high-conductivity) copper and CuAl25 (copper strengthened with a 0.25% atom fraction dispersion of alumina). The response of two fatigue specimen sizes to strain......Copper and its alloys are appealing for application in fusion reactor systems for high heat flux components where high thermal conductivities are critical, for instance, in divertor components. The thermal and mechanical loading of such components will be, at least in part, cyclic in nature, thus...

  17. Validity of fracture toughness determined with small bend specimens

    International Nuclear Information System (INIS)

    Wallin, K.; Rintamaa, R.; Valo, M.

    1994-02-01

    This report considers the validity of fracture toughness estimates obtained with small bend specimens in relation to fracture toughness estimates obtained with large specimens. The study is based upon the analysis and comparison of actual test results. The results prove the validity of the fracture toughness determined based upon small bend specimens, especially when the results are only used to determine the fracture toughness transition temperature T o . In this case the possible error is typically less than 5 deg C and at most 10 deg C. It can be concluded that small bend specimens are very suitable for the estimation of fracture toughness in the case of brittle fracture, provided the results are corrected for statistical size effects. (orig.). (20 refs., 17 figs.)

  18. Impact of specimen adequacy on the assessment of renal allograft biopsy specimens.

    Science.gov (United States)

    Cimen, S; Geldenhuys, L; Guler, S; Imamoglu, A; Molinari, M

    2016-01-01

    The Banff classification was introduced to achieve uniformity in the assessment of renal allograft biopsies. The primary aim of this study was to evaluate the impact of specimen adequacy on the Banff classification. All renal allograft biopsies obtained between July 2010 and June 2012 for suspicion of acute rejection were included. Pre-biopsy clinical data on suspected diagnosis and time from renal transplantation were provided to a nephropathologist who was blinded to the original pathological report. Second pathological readings were compared with the original to assess agreement stratified by specimen adequacy. Cohen's kappa test and Fisher's exact test were used for statistical analyses. Forty-nine specimens were reviewed. Among these specimens, 81.6% were classified as adequate, 6.12% as minimal, and 12.24% as unsatisfactory. The agreement analysis among the first and second readings revealed a kappa value of 0.97. Full agreement between readings was found in 75% of the adequate specimens, 66.7 and 50% for minimal and unsatisfactory specimens, respectively. There was no agreement between readings in 5% of the adequate specimens and 16.7% of the unsatisfactory specimens. For the entire sample full agreement was found in 71.4%, partial agreement in 20.4% and no agreement in 8.2% of the specimens. Statistical analysis using Fisher's exact test yielded a P value above 0.25 showing that - probably due to small sample size - the results were not statistically significant. Specimen adequacy may be a determinant of a diagnostic agreement in renal allograft specimen assessment. While additional studies including larger case numbers are required to further delineate the impact of specimen adequacy on the reliability of histopathological assessments, specimen quality must be considered during clinical decision making while dealing with biopsy reports based on minimal or unsatisfactory specimens.

  19. On the gradient plasticity approach to size effects. Pt. 1: reviews

    International Nuclear Information System (INIS)

    Malmberg, T.; Tsagrakis, I.; Eleftheriadis, I.; Aifantis, E.C.; Michigan Technol. Univ., Houghton, MI

    2001-03-01

    The influence of specimen size on the plastic deformation and failure behaviour of some metals and steels is considered. This size dependence issue relates to the question of the transferability of mechanical test results of geometrically similar scaled-down structural models to the full scale structures using similitude laws; but it concerns also the validity of small scale laboratory type test results and their use as a basis for the computational modelling of large scale components. In part I ''reviews'' of this report a restricted review of scaled experiments at room temperature of geometrically similar specimens is given. This refers to the initiation of yielding under non-uniform states of deformation and also to the plastic deformation and fracture of smooth tensile specimens. Among others, non-classical continuum mechanics theories have become a means to interpret size effects. Especially gradient concepts are of interest which enrich the classical plasticity theories by higher order spatial strain gradients. These model extensions implicate additional material parameters which can be associated with internal length scales characteristic for the material. In part I a brief review of several gradient theories of plasticity is also given, including both deformation and flow theories and a comparison of the original ''symmetric stress'' theory with the more recent ''asymmetric stress'' theory is provided. The forthcoming part II ''applications'' exemplifies to what extend strain gradient models can describe the size influence on the deformation behaviour. (orig.) [de

  20. Evaluation of fracture toughness of vessel materials using small-size specimens and full stress-strain curves

    Energy Technology Data Exchange (ETDEWEB)

    Lebedev, A A; Chausov, N G [Akademyiya Nauk Ukrayini, Kiev (Ukraine)

    1994-12-31

    Physically substantiated dependences between crack resistance characteristics determined by the parameters of descending sections of full stress-strain curves and stressed state rigidity at crack initiation moment, have been experimentally obtained. The possibility of crack resistance reliable estimation based on full stress-strain obtained using small-size specimens with different concentrators, has thus been experimentally substantiated. Results obtained by the method and actual temperature dependence of irradiated steel 15X2NMFA crack resistance characteristics, agreed well. 2 refs., 7 figs.

  1. Influence of specimen size and grain orientation to the life of a polycrystalline Ni-base alloy at LCF stress

    International Nuclear Information System (INIS)

    Seibel, Thomas

    2014-01-01

    In the present work the LCF (Low Cycle Fatigue) crack initiation life of the conventionally cast Ni-base alloy RENE 80 was analyzed as a function of specimen size and grain orientation. Five specimen geometries with distinctly different gauge sections were used: 3 geometries with cylindrical gauge section (G1-G3) and two notched geometries with a stress concentration factor of α 1 = 1,62 (KG1) and α 2 = 2,60 (KG2), resulting in a maximum difference of the damage relevant surface area up to a factor of approximately 72. Correction factors were determined by FEM calculations for all specimen geometries with highly reduced gauge sections where direct strain measurement was not possible. Additionally a uniform failure criterion with a relatively small crack size of 0,962 mm 2 was defined. Totally, 116 isothermal LCF tests were carried out at the different specimen types at a temperature of 850 C in total strain control with a load ratio (minimum strain / maximum strain) of R ε = -1. The load cycles were applied with triangular waveform at a frequency of 0.1 Hz for high strain amplitudes and 1 Hz for low strain amplitudes, respectively. After the LCF-Tests the fracture surfaces of all samples were analyzed in more detail by SEM to identify the crack initiation mechanisms as well as the crack initiation sites. In this context it could be shown, that fatigue cracks were generally initiated at slip bands in surface grains. Accordingly, the grain orientations at the crack initiation sites were measured by electron back scatter diffraction (EBSD) and the maximum shear stresses in the respective principal slip system (111) <110> was calculated using the Schmid approach. For this, longitudinal sections were be prepared exactly at the crack initiation sites of samples loaded with low strain amplitudes where clearly defined single crack initiation sites were observed. Afterwards the maximum shear stress in the principal slip system at the crack initiation site was correlated

  2. Size effect model for the edge strength of glass with cut and ground edge finishing

    NARCIS (Netherlands)

    Vandebroek, M.; Louter, C.; Caspeele, R.; Ensslen, F.; Belis, J.L.I.F.

    2014-01-01

    The edge strength of glass is influenced by the size of the surface (near the edge) which is subjected to tensile stresses. To quantify this size effect, 8 series of single layer annealed glass beam specimens (as-received glass) were subjected to in-plane four-point bending with linearly increased

  3. Thick Concrete Specimen Construction, Testing, and Preliminary Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Clayton, Dwight A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hoegh, Kyle [Univ. of Minnesota, Minneapolis, MN (United States); Khazanovich, Lev [Univ. of Minnesota, Minneapolis, MN (United States)

    2015-03-01

    initial results are also presented along with a discussion of the preliminary findings. Comparative NDE of various defects in reinforced concrete specimens is a key component in identifying the most promising techniques and directing the research and development efforts needed to characterize concrete degradation in commercial NPPs. This requires access to the specimens for data collection using state-of-the-art technology. The construction of the specimen detailed in this report allows for an evaluation of how different NDE techniques may interact with the size and complexities of NPP concrete structures. These factors were taken into account when determining specimen size and features to ensure a realistic design. The lateral dimensions of the specimen were also chosen to mitigate unrealistic boundary effects that would not affect the results of field NPP concrete testing. Preliminary results show that, while the current methods are able to identify some of the deeper defects, improvements in data processing or hardware are necessary to be able to achieve the precision and reliability achieved in evaluating thinner and less heavily reinforced concrete structures.

  4. Analysis of size effect applicable to evaluation of fracture toughness of base metal for PWR vessel

    International Nuclear Information System (INIS)

    Benhamou, C.; Joly, P.; Andrieu, A.; Parrot, A.; Vidard, S.

    2015-01-01

    The objective of the present paper is to review the specimen size effect (also called crack front length effect) on Fracture Toughness of PWR Reactor Pressure Vessel Steel base metal. The analysis of the reality and amplitude of this effect is conducted in a first step on a database (the so-called GKSS database) including fracture toughness test results on a single representative material using specimens of different thicknesses, tested in the same temperature range. A realistic analytical form for describing the size effect observed in this data set is thus derived from statistical analyses and proposed for engineering application. In a second step, this size effect formulation is then applied to a large number of fracture toughness data, obtained in Irradiation Surveillance Programs, and also to the numerous data used for the definition of the ASME (and RCC-M) fracture toughness reference curves. This analysis allows normalizing all the available fracture toughness data with a single specimen width of 100 mm and defining the fracture toughness reference curve as the lower bound of this normalized set of data points. It is thus demonstrated that the fracture toughness reference curve is associated with a reference crack length of 100 mm, and can be used in RPV integrity analyses for other crack front length in association with the crack front length correction formula defined in the first step. (authors)

  5. Capillary Versus Aspiration Biopsy: Effect of Needle Size and Length on the Cytopathological Specimen Quality

    International Nuclear Information System (INIS)

    Hopper, Kenneth D.; Grenko, Ronald T.; Fisher, Alicia I.; TenHave, Thomas R.

    1996-01-01

    Purpose: To test the value of the nonaspiration, or capillary, biopsy technique by experimental comparison with the conventional fine-needle aspiration technique using various needle gauges and lengths. Methods: On fresh hepatic and renal tissue from five autopsies, multiple biopsy specimens were taken with 20, 22, and 23-gauge Chiba needles of 5, 10, 15, and 20-cm length, using the aspiration technique and the capillary technique. The resultant specimens were graded on the basis of a grading scheme by a cytopathologist who was blinded to the biopsy technique. Results: The capillary technique obtained less background blood or clot which could obscure diagnostic tissue, although not significantly different from the aspiration technique (p= 0.2). However, for the amount of cellular material obtained, retention of appropriate architecture, and mean score, the capillary technique performed statistically worse than aspiration biopsy (p < 0.01). In addition, with decreasing needle caliber (increasing needle gauge) and increasing length, the capillary biopsy was inferior to the aspiration biopsy. Conclusion: The capillary biopsy technique is inferior to the aspiration technique according to our study. When the capillary technique is to be applied, preference should be given to larger caliber, shorter needles

  6. The effect of specimen size on the ductile/brittle transition temperature in an A533B pressure vessel steel

    International Nuclear Information System (INIS)

    Green, G.; Knott, J.F.

    It was ascertained that it is possible to relate critical crack opening displacement (COD) values, deltasub(crit), obtained on small specimens of A 533-B pressure vessel steel to the fracture toughness value representing the initiation of fracture in a large structure. The variation of deltasub(crit) with temperature is given. A sharp increase in deltasub(crit) is observed above a temperature of approximately -100 degC and this was found to be associated with the initiation of small amounts of fibrous fracture, prior to a cleavage instability. An upper limit to the deltasub(crit) values was obtained above -50 degC, where the fracture was found to be fully ductile. Values of deltasub(crit) estimated from the valid fracture toughness results are shown for comparison. At low temperatures the estimated deltasub(crit) values are seen to be less than those measured in the small bend specimens and the sharp increase in the estimated deltasub(crit) values occurs at a higher temperature, approximately 0 degC. The room temperature deltasub(crit) value, estimated from the valid toughness results (0.15 mm) compares well with COD for the initiation of fibrous fracture, measured at the same temperature in small bend specimens (0.175 mm). The following conclusions were drawn from the experiments: 1. The ductile/brittle transition temperature, determined by critical COD measurements, is influenced by the relaxation of triaxial stresses in small specimens. 2. It is possible to relate critical COD values for the initiation of fibrous fracture, measured in small specimens, to the fracture toughness representing this behaviour in a large structure

  7. The effects of surface finish and grain size on the strength of sintered silicon carbide

    Science.gov (United States)

    You, Y. H.; Kim, Y. W.; Lee, J. G.; Kim, C. H.

    1985-01-01

    The effects of surface treatment and microstructure, especially abnormal grain growth, on the strength of sintered SiC were studied. The surfaces of sintered SiC were treated with 400, 800 and 1200 grit diamond wheels. Grain growth was induced by increasing the sintering times at 2050 C. The beta to alpha transformation occurred during the sintering of beta-phase starting materials and was often accompanied by abnormal grain growth. The overall strength distributions were established using Weibull statistics. The strength of the sintered SiC is limited by extrinsic surface flaws in normal-sintered specimens. The finer the surface finish and grain size, the higher the strength. But the strength of abnormal sintering specimens is limited by the abnormally grown large tabular grains. The Weibull modulus increases with decreasing grain size and decreasing grit size for grinding.

  8. Sample size effect on the determination of the irreversibility line of high-Tc superconductors

    International Nuclear Information System (INIS)

    Li, Q.; Suenaga, M.; Li, Q.; Freltoft, T.

    1994-01-01

    The irreversibility lines of a high-J c superconducting Bi 2 Sr 2 Ca 2 Cu 3 O x /Ag tape were systematically measured upon a sequence of subdivisions of the sample. The irreversibility field H r (T) (parallel to the c axis) was found to change approximately as L 0.13 , where L is the effective dimension of the superconducting tape. Furthermore, it was found that the irreversibility line for a grain-aligned Bi 2 Sr 2 Ca 2 Cu 3 O x specimen can be approximately reproduced by the extrapolation of this relation down to a grain size of a few tens of micrometers. The observed size effect could significantly obscure the real physical meaning of the irreversibility lines. In addition, this finding surprisingly indicated that the Bi 2 Sr 2 Ca 2 Cu 2 O x /Ag tape and grain-aligned specimen may have similar flux line pinning strength

  9. Modelling and experimental characterisation of a residual stress field in a ferritic compact tension specimen

    International Nuclear Information System (INIS)

    Wenman, M.R.; Price, A.J.; Steuwer, A.; Chard-Tuckey, P.R.; Crocombe, A.

    2009-01-01

    The aim of the work is to elucidate the influence of plasticity behaviour on the residual stress field in a ferritic reactor pressure vessel steel. To this end, we investigate two compressively pre-loaded compact tension (CT) specimens to generate a mechanical residual stress field. One specimen was subsequently pre-cracked by fatigue before both specimens were measured using high-energy synchrotron X-ray diffraction. A fine grain size microstructure (∼5-10 μm grain size) allowed a small X-ray beam slit size and therefore gauge volume. The results provide an excellent data set for validation of finite element (FE) modelling predictions against which they have been compared. The results of both mechanical testing and modelling suggest that the use of a combined hardening model is needed to accurately predict the residual stress field present in the specimen after pre-loading. Some discrepancy between the modelled crack tip stress values and those found by X-ray diffraction remain which can be partly explained by volume averaging effects in the presence of very high stress/strain gradients.

  10. Modelling and experimental characterisation of a residual stress field in a ferritic compact tension specimen

    Energy Technology Data Exchange (ETDEWEB)

    Wenman, M.R., E-mail: m.wenman@imperial.ac.u [Department of Materials, Imperial College London, London SW7 2AZ (United Kingdom); Price, A.J. [Faculty of Engineering and Physical Sciences (J5), University of Surrey, Guildford GU2 7XH (United Kingdom); Steuwer, A. [ESS Scandinavia, Stora Algatan 4, 22350 Lund (Sweden) and Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa); Chard-Tuckey, P.R. [Nuclear Department, Defence College of Management and Technology, HMS Sultan, Gosport, Hants PO12 3BY (United Kingdom); Crocombe, A. [Faculty of Engineering and Physical Sciences (J5), University of Surrey, Guildford GU2 7XH (United Kingdom)

    2009-12-15

    The aim of the work is to elucidate the influence of plasticity behaviour on the residual stress field in a ferritic reactor pressure vessel steel. To this end, we investigate two compressively pre-loaded compact tension (CT) specimens to generate a mechanical residual stress field. One specimen was subsequently pre-cracked by fatigue before both specimens were measured using high-energy synchrotron X-ray diffraction. A fine grain size microstructure (approx5-10 mum grain size) allowed a small X-ray beam slit size and therefore gauge volume. The results provide an excellent data set for validation of finite element (FE) modelling predictions against which they have been compared. The results of both mechanical testing and modelling suggest that the use of a combined hardening model is needed to accurately predict the residual stress field present in the specimen after pre-loading. Some discrepancy between the modelled crack tip stress values and those found by X-ray diffraction remain which can be partly explained by volume averaging effects in the presence of very high stress/strain gradients.

  11. Size Effect on Acoustic Emission Characteristics of Coal-Rock Damage Evolution

    Directory of Open Access Journals (Sweden)

    Zhijie Wen

    2017-01-01

    Full Text Available Coal-gas outburst, rock burst, and other mine dynamic disasters are closely related to the instability and failure of coal-rock. Coal-rock is the assemblies of mineral particles of varying sizes and shapes bonded together by cementing materials. The damage and rupture process of coal-rock is accompanied by acoustic emission (AE, which can be used as an effective means to monitor and predict the instability of coal-rock body. In this manuscript, considering the size effect of coal-rock, the influence of different height to diameter ratio on the acoustic emission characteristics of coal-rock damage evolution was discussed by microparticle flow PFC2D software platform. The results show that coal-rock size influences the uniaxial compressive strength, peak strain, and elastic modulus of itself; the size effect has little effect on the acoustic emission law of coal-rock damage and the effects of the size of coal-rock samples on acoustic emission characteristics are mainly reflected in three aspects: the triggering time of acoustic emission, the strain range of strong acoustic emission, and the intensity of acoustic emission; the damage evolution of coal-rock specimen can be divided into 4 stages: initial damage, stable development, accelerated development, and damage.

  12. Size effect in X-ray and electron diffraction patterns from hydroxyapatite particles

    International Nuclear Information System (INIS)

    Suvorova, E.I.; Buffat, P.-A.

    2001-01-01

    High-resolution transmission electron microscopy (HRTEM), electron microdiffraction, and X-ray diffraction were used to study hydroxyapatite specimens with particle sizes from a few nanometers to several hundreds of nanometers. Diffuse scattering (without clear reflections in transmission diffraction patterns) or strongly broadened peaks in X-ray diffraction patterns are characteristic for agglomerated hydroxyapatite nanocrystals. However, HRTEM and microdiffraction showed that this cannot be considered as an indication of the amorphous state of the matter but rather as the demonstration of size effect and the morphological and structural features of hydroxyapatite nanocrystals

  13. High inter-specimen variability of baseline data for the tibio-talar contact area.

    Science.gov (United States)

    Matricali, Giovanni A; Bartels, Ward; Labey, Luc; Dereymaeker, Greta Ph E; Luyten, Frank P; Vander Sloten, Jos

    2009-01-01

    The tibio-talar contact area has been widely investigated to monitor biomechanical changes due to articular incongruities or an altered loading. This study aims to investigate for the first time in a systematic way the extent of the inter-specimen variability of the tibio-talar contact area, and its repercussions when analyzing data concerning this parameter. Ten specimens were loaded to record the tibio-talar contact characteristics by use of pressure sensitive film. The size of the talar dome area, the size of the (normalized) tibio-talar contact area, the position of the tibio-talar contact area, and the shape of the latter were determined and analyzed. Inter-specimen variability was expressed as the coefficient of variation and was calculated for the datasets of previous studies as well. The size of the tibio-talar contact area showed a very high inter-specimen variability, as is the case in previous studies. This high variability persisted when a normalized tibio-talar contact area was calculated. The shape of the tibio-talar contact area showed some basic characteristics, but a high variation in details could be observed. Every specimen can be considered to have its own "ankle print". By this variability, articular incongruities are expected to have a different effect on local biomechanical characteristics in every single individual. Therefore, every single case has to be evaluated and reported for significant changes. In case of modeling, this also underscores the need to use subject specific models fed by sets of parameters derived from a series of single specimens.

  14. Atomistic origin of size effects in fatigue behavior of metallic glasses

    Science.gov (United States)

    Sha, Zhendong; Wong, Wei Hin; Pei, Qingxiang; Branicio, Paulo Sergio; Liu, Zishun; Wang, Tiejun; Guo, Tianfu; Gao, Huajian

    2017-07-01

    While many experiments and simulations on metallic glasses (MGs) have focused on their tensile ductility under monotonic loading, the fatigue mechanisms of MGs under cyclic loading still remain largely elusive. Here we perform molecular dynamics (MD) and finite element simulations of tension-compression fatigue tests in MGs to elucidate their fatigue mechanisms with focus on the sample size effect. Shear band (SB) thickening is found to be the inherent fatigue mechanism for nanoscale MGs. The difference in fatigue mechanisms between macroscopic and nanoscale MGs originates from whether the SB forms partially or fully through the cross-section of the specimen. Furthermore, a qualitative investigation of the sample size effect suggests that small sample size increases the fatigue life while large sample size promotes cyclic softening and necking. Our observations on the size-dependent fatigue behavior can be rationalized by the Gurson model and the concept of surface tension of the nanovoids. The present study sheds light on the fatigue mechanisms of MGs and can be useful in interpreting previous experimental results.

  15. Evaluations of environmental effect on micro crack initiation and propagation by surface observations of fatigue specimens

    International Nuclear Information System (INIS)

    Fujikawa, Ryosuke; Abe, Shigeki; Nakamura, Takao; Kamaya, Masayuki

    2014-01-01

    Fatigue life of nuclear facilities tends to be decreased by the influence of reactor coolant, which is called environmental effect. The effect accelerates crack growth rate but the influence for crack initiation is not clarified. This study intends to discuss the environmental effect in crack initiation. The crack length and the number of cracks are measured from the investigation of fatigue test specimens in reactor coolant and air. The behavior of crack initiation is revealed from the measurement of number of cracks, crack sizes and fatigue life. From this study, environmental effect of reactor coolant is considered to influence crack initiation and increase the number of micro crack. It is also estimated that the coalescence of cracks influences the acceleration of crack growth. (author)

  16. The response of pressure vessel steel specimens on drop weight loading

    International Nuclear Information System (INIS)

    Winkler, S.; Kalthoff, J.F.; Gerscha, A.

    1979-01-01

    Load records obtained in instrumented impact tests in general are disturbed by inertia effects. The influence of mechanical damping provisions on these disturbing inertia effects is investigated. Precracked bend specimens are dynamically loaded in a drop weight testing system. The specimens of size 620 mm x 150 mm (25 mm or 50 mm thick) were machined from the pressure vessel steel 22 NiMoCr 37 which was heat treated to achieve a specially hardened condition. The tests were performed at two different low temperatures. The impact velocity was about 4 m/s. As it is usual in instrumented impact testing, the load at the tup of the impining striker is recorded as a function of time during the impact process. In addition the specimen is instrumented by a strain gage close to the crack tip in order to directly measure the stress intensification. Experiments were performed under pure and damped impact conditions. Damping was achieved by utilizing a soft aluminum plate between the striker and the specimen. (orig.)

  17. Toughening MoSi2 with Niobium metal -- Effects of size and orientation of ductile laminae

    International Nuclear Information System (INIS)

    Shaw, L.; Abbaschian, R.

    1994-01-01

    Effects of size and orientation of ductile laminae on the toughness of brittle matrix composites have been evaluated using MoSi 2 composites reinforced with Nb laminae. Nb laminae with thicknesses ranging from 0.127 to 1.0 mm were hot pressed with MoSi 2 powder to prepare the composites. Toughness of the composites was measured using four-point bend test on chevron-notched specimens. It was found that the toughness of the composites increased with increasing size of the niobium laminae. Furthermore, toughening was observed at crack propagation directions perpendicular to the laminae plane, indicating that ductile laminae offer two dimensional toughening. A model based on the bridging contribution of the ductile phase has been proposed to analyze the chevron-notched specimens of the ductile-phase-reinforced brittle matrix composites. The analysis showed that the dependence of the toughness of the composites on the size and orientation of the ductile laminae could be interpreted in terms of their bridging capability and bending contributions

  18. Methods and devices for small specimen testing at the Japan Atomic Energy Research Institute

    International Nuclear Information System (INIS)

    Jitsukawa, Shiro; Kizaki, Minoru; Umino, Akira; Shiba, Kiyoyuki; Hishinuma, Akimichi

    1993-01-01

    Devices for a punch test on annular notched specimens, small punch (SP) tests, and miniaturized tension tests in hot cells were developed. A micro-manipulator to handle small specimens and an electro-discharge machine (EDM) to extract miniaturized tension specimens and annular notched specimens from transmission electron microscopy (TEM) disks were also fabricated. These devices were designed and made for remote operation in hot cells. Preliminary tests to evaluate the applicability of test methods were carried out. Correlation between SP test results and tensile properties was not strong. Miniaturized tensile results were reasonably similar to the results with larger specimens. The ductile-brittle transition temperature (DBTT) by the punch test on annular notched specimens was higher than that obtained from the SP test. However, materials dependence of the DBTT was different from that measured by standard Charpy V-notch (CVN) tests. This may be due to a specimen size effect

  19. System size effects on the mechanical response of cohesive-frictional granular ensembles

    Directory of Open Access Journals (Sweden)

    Singh Saurabh

    2017-01-01

    Full Text Available Shear resistance in granular ensembles is a result of interparticle interaction and friction. However, even the presence of small amounts of cohesion between the particles changes the landscape of the mechanical response considerably. Very often such cohesive frictional (c-ϕ granular ensembles are encountered in nature as well as while handling and storage of granular materials in the pharmaceutical, construction and mining industries. Modeling of these c-ϕ materials, especially in engineering applications have relied on the oft-made assumption of a “continua” and have utilized the popular tenets of continuum plasticity theory. We present an experimental investigation on the fundamental mechanics of c-ϕ materials specifically; we investigate if there exists a system size effect and any additional length scales beyond the continuum length scale on their mechanical response. For this purpose, we conduct a series of 1-D compression (UC tests on cylindrical specimens reconstituted in the laboratory with a range of model particle–binder combinations such as sandcement, sand-epoxy, and glass ballotini-epoxy mixtures. Specimens are reconstituted to various diameters ranging from 10 mm to 150 mm (with an aspect ratio of 2 to a predefined packing fraction. In addition to the effect of the type of binder (cement, epoxy and system size, the mean particle size is also varied from 0.5 to 2.5 mm. The peak strength of these materials is significant as it signals the initiation of the cohesive-bond breaking and onset of mobilization of the inter particle frictional resistance. For these model systems, the peak strength is a strong function of the system size of the ensemble as well as the mean particle size. This intriguing observation is counter to the traditional notion of a continuum plastic typical granular ensemble. Microstructure studies in a computed-tomograph have revealed the existence of a web patterned ‘entangled-chain’ like structure

  20. System size effects on the mechanical response of cohesive-frictional granular ensembles

    Science.gov (United States)

    Singh, Saurabh; Kandasami, Ramesh Kannan; Mahendran, Rupesh Kumar; Murthy, Tejas

    2017-06-01

    Shear resistance in granular ensembles is a result of interparticle interaction and friction. However, even the presence of small amounts of cohesion between the particles changes the landscape of the mechanical response considerably. Very often such cohesive frictional (c-ϕ) granular ensembles are encountered in nature as well as while handling and storage of granular materials in the pharmaceutical, construction and mining industries. Modeling of these c-ϕ materials, especially in engineering applications have relied on the oft-made assumption of a "continua" and have utilized the popular tenets of continuum plasticity theory. We present an experimental investigation on the fundamental mechanics of c-ϕ materials specifically; we investigate if there exists a system size effect and any additional length scales beyond the continuum length scale on their mechanical response. For this purpose, we conduct a series of 1-D compression (UC) tests on cylindrical specimens reconstituted in the laboratory with a range of model particle-binder combinations such as sandcement, sand-epoxy, and glass ballotini-epoxy mixtures. Specimens are reconstituted to various diameters ranging from 10 mm to 150 mm (with an aspect ratio of 2) to a predefined packing fraction. In addition to the effect of the type of binder (cement, epoxy) and system size, the mean particle size is also varied from 0.5 to 2.5 mm. The peak strength of these materials is significant as it signals the initiation of the cohesive-bond breaking and onset of mobilization of the inter particle frictional resistance. For these model systems, the peak strength is a strong function of the system size of the ensemble as well as the mean particle size. This intriguing observation is counter to the traditional notion of a continuum plastic typical granular ensemble. Microstructure studies in a computed-tomograph have revealed the existence of a web patterned `entangled-chain' like structure, we argue that this ushers

  1. Analysis on the stress corrosion crack inception based on pit shape and size of the FV520B tensile specimen

    Science.gov (United States)

    Xiang, Longhao; Pan, Juyi; Chen, Songying

    2018-06-01

    The influence of pit shape and size on local stress concentration in the tensile specimen and the stress corrosion cracks inception was studied by employing the element remove technique. The maximum stress located in the bottom of pit on FV520B tensile specimen. The location of maximum strain was near the mouth of the pit or the shoulder and plastic strain existed in this region. Stress concentration factor and plastic deformation on four different geometrical shape pits of hemisphere, semi-ellipsoid, bullet and butterfly were numerically investigated, respectively. The simulation results showed that butterfly pit got the biggest stress concentration factor. The plastic strain rate during pit growth was in the sensitivity range of stress corrosion cracks inception, indicating that stress corrosion cracks were more likely to nucleate near the pit tip or the shoulder.

  2. Yield of two consecutive sputum specimens for the effective diagnosis of pulmonary tuberculosis.

    Directory of Open Access Journals (Sweden)

    Mohammad R Islam

    Full Text Available BACKGROUND: From long instances, it is debatable whether three sputum specimens are required for the diagnosis of pulmonary tuberculosis (TB or TB can be diagnosed effectively using two consecutive sputum specimens. This study was set out to evaluate the significance of examining multiple sputum specimens in diagnosis of TB. METHODS: We retrospectively reviewed the acid-fast bacillus (AFB smear and culture results of three consecutive days' sputum specimens from 413 confirmed TB patients which were detected as part of a larger active case finding study in Dhaka Central Jail, the largest correctional facility in Bangladesh. RESULTS: AFB was detected from 81% (n = 334 patients, of which 89% (n = 297 were diagnosed from the first and additional 9% (n = 30 were from the second sputum specimen. M. tuberculosis growth was observed for 406 patients and 85% (n = 343 were obtained from the first sputum and additional 10% (n = 42 were from the second one. The third specimen didn't show significant additional diagnostic value for the detection of AFB by microscopy or growth of the M. tuberculosis. CONCLUSIONS: We concluded from our study results that examining two consecutive sputum specimens is sufficient enough for the effective diagnosis of TB. It can also decrease the laboratory workload and hence improve the quality of work in settings with high TB burden like Bangladesh.

  3. Yield of two consecutive sputum specimens for the effective diagnosis of pulmonary tuberculosis.

    Science.gov (United States)

    Islam, Mohammad R; Khatun, Razia; Uddin, Mohammad Khaja Mafij; Khan, Md Siddiqur Rahman; Rahman, Md Toufiq; Ahmed, Tahmeed; Banu, Sayera

    2013-01-01

    From long instances, it is debatable whether three sputum specimens are required for the diagnosis of pulmonary tuberculosis (TB) or TB can be diagnosed effectively using two consecutive sputum specimens. This study was set out to evaluate the significance of examining multiple sputum specimens in diagnosis of TB. We retrospectively reviewed the acid-fast bacillus (AFB) smear and culture results of three consecutive days' sputum specimens from 413 confirmed TB patients which were detected as part of a larger active case finding study in Dhaka Central Jail, the largest correctional facility in Bangladesh. AFB was detected from 81% (n = 334) patients, of which 89% (n = 297) were diagnosed from the first and additional 9% (n = 30) were from the second sputum specimen. M. tuberculosis growth was observed for 406 patients and 85% (n = 343) were obtained from the first sputum and additional 10% (n = 42) were from the second one. The third specimen didn't show significant additional diagnostic value for the detection of AFB by microscopy or growth of the M. tuberculosis. We concluded from our study results that examining two consecutive sputum specimens is sufficient enough for the effective diagnosis of TB. It can also decrease the laboratory workload and hence improve the quality of work in settings with high TB burden like Bangladesh.

  4. Assessment of bone biopsy needles for sample size, specimen quality and ease of use

    International Nuclear Information System (INIS)

    Roberts, C.C.; Liu, P.T.; Morrison, W.B.; Leslie, K.O.; Carrino, J.A.; Lozevski, J.L.

    2005-01-01

    To assess whether there are significant differences in ease of use and quality of samples among several bone biopsy needles currently available. Eight commonly used, commercially available bone biopsy needles of different gauges were evaluated. Each needle was used to obtain five consecutive samples from a lamb lumbar pedicle. Subjective assessment of ease of needle use, ease of sample removal from the needle and sample quality, before and after fixation, was graded on a 5-point scale. The number of attempts necessary to reach a 1 cm depth was recorded. Each biopsy specimen was measured in the gross state and after fixation. The RADI Bonopty 15 g and Kendall Monoject J-type 11 g needles were rated the easiest to use, while the Parallax Core-Assure 11 g and the Bard Ostycut 16 g were rated the most difficult. Parallax Core-Assure and Kendall Monoject needles had the highest quality specimen in the gross state; Cook Elson/Ackerman 14 g and Bard Ostycut 16 g needles yielded the lowest. The MD Tech without Trap-Lok 11 g needle had the highest quality core after fixation, while the Bard Ostycut 16 g had the lowest. There was a significant difference in pre-fixation sample length between needles (P<0.0001), despite acquiring all cores to a standard 1 cm depth. Core length and width decrease in size by an average of 28% and 42% after fixation. Bone biopsy needles vary significantly in performance. Detailed knowledge of the strengths and weaknesses of different needles is important to make an appropriate selection for each individual's practice. (orig.)

  5. Transmission electron microscopy of bulk specimens over 10 µm in thickness

    Energy Technology Data Exchange (ETDEWEB)

    Sadamatsu, Sunao, E-mail: sadamatsu@mech.kagoshima-u.ac.jp [Department of Mechanical Engineering, Kagoshima University, Korimoto, Kagoshima 890-0065 (Japan); Tanaka, Masaki; Higashida, Kenji [Department of Materials Science and Engineering, Kyushu University, Nishi-ku, Fukuoka 819-0395 (Japan); Matsumura, Syo [Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Nishi-ku, Fukuoka 819-0395 (Japan); Ultramicroscopy Research Center, Kyushu University, Nishi-ku, Fukuoka 819-0395 (Japan)

    2016-03-15

    We succeeded the observation of microstructures in bulk-sized specimens of over 10 µm in thickness by employing a technique that combines transmission electron microscopy (TEM) with energy-filtered imaging based on electron energy-loss spectroscopy (EELS). This method is unique in that it incorporates the inelastically scattered electrons into the imaging process. Using this technique, bright and sharp images of dislocations in crystalline silicon specimens as thick as 10 µm were obtained. A calibration curve to determine foil thickness of such a thick specimen was also derived. This method simply extends the observable thickness range in TEM. If combined with tilt series of observation over a significant range of angle, it will disclose three dimensional nanostructures in a µm-order block of a specimen, promoting our understanding of the controlling mechanisms behind various bulky material properties. - Highlights: • We developed a method which enables thick specimens to be observed using EF-TEM. • The effects of energy filter width and position on images were determined. • We suggested a method to determine the thickness of a thick film sample. • We achieved observation of microstructures in specimens with a thickness of 10 µm.

  6. On the Da Vinci size effect in tensile strengths of nanowires: A molecular dynamics study

    Science.gov (United States)

    Zhao, Ziyu; Liu, Jinxing; Soh, Ai Kah

    2018-01-01

    In recent decades, size effects caused by grain size, strain gradient, typical defects etc., have been widely investigated. Nevertheless, the dependence of tensile strength on the specimen length, addressed by Da Vinci around 500 hundred years ago, has received rather limited attention, even though it is one unavoidable question to answer if people attempt to bring materials' amazing nano-scale strengths up to macro-level. Therefore, we make efforts to study tensile behaviors of copper nanowires with a common cross-section and various lengths by employing the molecular dynamics simulations. Surprisingly, a strong size effect of Da Vinci type indeed arises. We have shown the influences of lattice orientation, temperature and prescribed notch on such a Da Vinci size effect. Two different theoretical explanations are briefly proposed for a qualitative understanding. Finally, a simple scaling rule is summarized to cover the tendencies observed.

  7. TEM specimen preparation of semiconductor-PMMA-metal interfaces

    International Nuclear Information System (INIS)

    Thangadurai, P.; Lumelsky, Yulia; Silverstein, Michael S.; Kaplan, Wayne D.

    2008-01-01

    Transmission electron microscopy (TEM) cross-section specimens of PMMA in contact with gold and Si were prepared by focused ion beam (FIB) and compared with plan-view PMMA specimens prepared by a dip-coating technique. The specimens were characterized by TEM and electron energy loss spectroscopy (EELS). In the cross-section specimens, the thin films of PMMA were located in a Si-PMMA-Au multilayer. Different thicknesses of PMMA films were spin-coated on the Si substrates. The thickness of the TEM specimens prepared by FIB was estimated using EELS to be 0.65 of the plasmon mean-free-path. Along the PMMA-Au interface, Au particle diffusion into the PMMA was observed, and the size of the Au particles was in the range of 2-4 nm. Dip-coating of PMMA directly on Cu TEM grids resulted in thin specimens with a granular morphology, with a thickness of 0.58 of the plasmon mean-free-path. The dip-coated specimens were free from ion milling induced artifacts, and thus serve as control specimens for comparison with the cross-sectioned specimens prepared by FIB

  8. Characterization of test specimens produced in reduced size for X-ray microtomography (µ-CT tests

    Directory of Open Access Journals (Sweden)

    E. E. BERNARDES

    Full Text Available Abstract The need to use reduced sample sizes, in order to attain improved spatial resolution in (µ-CT tests applied in Portland cement composites, makes researchers perform the fractionation of materials to obtain samples with dimensions compatible with the capacity of the scanning equipment, which might cause alterations in the microstructure under analysis. Therefore, a test specimen (TS with dimensions compatible with the scanning capacity of a microtomography system that operates with an X-ray tube and voltage ranging from 20 to 100 kV was proposed. Axial compression strength tests were made and their total porosity was assessed by an apparent density and solid fraction density ratio, which were obtained by means of mercury and helium pycnometry and µ-CT technique, respectively. The adoption of that TS has shown to be viable for providing a sample with a higher level of representation.

  9. A triple-scale crystal plasticity modeling and simulation on size effect due to fine-graining

    International Nuclear Information System (INIS)

    Kurosawa, Eisuke; Aoyagi, Yoshiteru; Tadano, Yuichi; Shizawa, Kazuyuki

    2010-01-01

    In this paper, a triple-scale crystal plasticity model bridging three hierarchical material structures, i.e., dislocation structure, grain aggregate and practical macroscopic structure is developed. Geometrically necessary (GN) dislocation density and GN incompatibility are employed so as to describe isolated dislocations and dislocation pairs in a grain, respectively. Then the homogenization method is introduced into the GN dislocation-crystal plasticity model for derivation of the governing equation of macroscopic structure with the mathematical and physical consistencies. Using the present model, a triple-scale FE simulation bridging the above three hierarchical structures is carried out for f.c.c. polycrystals with different mean grain size. It is shown that the present model can qualitatively reproduce size effects of macroscopic specimen with ultrafine-grain, i.e., the increase of initial yield stress, the decrease of hardening ratio after reaching tensile strength and the reduction of tensile ductility with decrease of its grain size. Moreover, the relationship between macroscopic yielding of specimen and microscopic grain yielding is discussed and the mechanism of the poor tensile ductility due to fine-graining is clarified. (author)

  10. On the Da Vinci size effect in tensile strengths of nanowires: A molecular dynamics study

    Directory of Open Access Journals (Sweden)

    Ziyu Zhao

    2018-01-01

    Full Text Available In recent decades, size effects caused by grain size, strain gradient, typical defects etc., have been widely investigated. Nevertheless, the dependence of tensile strength on the specimen length, addressed by Da Vinci around 500 hundred years ago, has received rather limited attention, even though it is one unavoidable question to answer if people attempt to bring materials’ amazing nano-scale strengths up to macro-level. Therefore, we make efforts to study tensile behaviors of copper nanowires with a common cross-section and various lengths by employing the molecular dynamics simulations. Surprisingly, a strong size effect of Da Vinci type indeed arises. We have shown the influences of lattice orientation, temperature and prescribed notch on such a Da Vinci size effect. Two different theoretical explanations are briefly proposed for a qualitative understanding. Finally, a simple scaling rule is summarized to cover the tendencies observed.

  11. Size Effect Studies on Tensile Tests for Hot Stamping Steel

    Science.gov (United States)

    Chen, Xiaodu; Li, Yuanyuan; Han, Xianhong; Zhang, Junbo

    2018-02-01

    Tensile tests have been widely used to determine basic mechanical properties of materials. However, the properties measured may be related to geometrical factors of the tested samples especially for high-strength steels; this makes the properties' definitions and comparisons difficult. In this study, a series of tensile tests of ultra-high-strength hot-stamped steel were performed; the geometric shapes and sizes as well as the cutting direction were modified. The results demonstrate that the hot-stamped parts were isotropic and the cutting direction had no effect; the measured strengths were practically unrelated to the specimen geometries, including both size and shape. The elongations were slightly related to sample sizes within the studied range but highly depended on the sample shape, represented by the coefficient K. Such phenomena were analyzed and discussed based on microstructural observations and fracture morphologies. Moreover, two widely used elongation conversion equations, the Oliver formula and Barba's law, were introduced to verify their applicability, and a new interpolating function was developed and compared.

  12. Fracture toughness measurements with subsize disk compact specimens

    International Nuclear Information System (INIS)

    Alexander, D.J.

    1992-01-01

    Special fixtures and test methods are necessary to facilitate the fracture toughness testing of small disk compact specimens of irradiated candidate materials for first-wall fusion applications. New methods have been developed for both the unloading compliance and potential drop techniques of monitoring crack growth. Provisions have been made to allow the necessary probes and instrumentation to be installed remotely using manipulators for testing of irradiated specimens in a hot cell. Laboratory trials showed that both unloading compliance and potential drop gave useful results. Both techniques gave similar data, and predicted the final crack extension within allowable limits. The results from the small disk compact specimens were similar to results from conventional compact specimen 12.7 mm thick. However, the slopes of the J-R curves from the larger specimens were lower, suggesting that the smaller disk compact specimens may have lost some constraint due to their size. The testing shows that it should be possible to generate useful J-R curve fracture toughness data from the small disk compact specimens

  13. Fracture toughness measurements with subsize disk compact specimens

    International Nuclear Information System (INIS)

    Alexander, D.J.

    1992-01-01

    Special fixtures and test methods have been developed for testing small disk compact specimens (12.5 mm diam by 4.6 mm thick). Both unloading compliance and potential drop methods have been used to monitor crack extension during the J-integral resistance (J-R) curve testing. Provisions have been made to allow the necessary probes and instrumentation to be installed remotely using manipulators for testing of irradiated specimens in a hat cell. Laboratory trials showed that both unloading compliance and potential drop gave useful results. Both techniques gave similar data, and predicted the final crack extension within allowable limits. The results from the small disk compact specimens were similar to results from conventional compact specimens 12.7-mm thick. However, the slopes of the J-R curves from the larger specimens were lower, suggesting that the smaller disk compact specimens may have lost some constraint due to their size. The testing shows that it should be possible to generate useful J-R curve fracture toughness data from the small disk compact specimens

  14. Effect of Ti content on grain size and mechanical properties of UNS S44100 ferritic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Y. [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Mao, W.M., E-mail: weiminmao@263.net [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Chen, Y.J. [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Jing, J.; Cheng, M. [Taizhou Xinyu Precision Manufacture Company Limited, Jiangyan 225500, Jiangsu (China)

    2016-11-20

    The effect of Ti contents between 0.10 and 0.50 wt% on the grain size and mechanical properties of UNS S44100 ferritic stainless steel produced by investment casting was investigated. The mechanical properties were related to tensile strength and elongation. The average grain sizes of the as-cast specimens decreased obviously with increasing Ti content due to the increasing number of (Ti,Nb)(C,N) precipitates, with sizes of 2.0–4.0 µm, acting as the nuclei for heterogeneous nucleation. The average sizes of TiN clusters in steels 2 and 3 were 3.6 and 7.0 µm, respectively, whereas no TiN clusters were discovered in steel 1 with 0.13 wt% Ti. The experimental results were in good agreement with the thermodynamic analysis of TiN formation. The precipitation temperature of TiN showed a rising trend with increasing Ti content, which implies that larger TiN clusters are more likely to be induced with Ti contents greater than 0.30 wt%. Some as-cast specimens were normalized at 850 °C for 2 h in order to improve the mechanical properties. In addition, the morphology of the TiN clusters, which caused a sharply decline in the mechanical properties of the as-cast specimens with increasing Ti content, showed no change after normalizing. The tensile strengths of the normalized specimens in the three steels increased to different degrees and the improvement of elongation in steel 1 was remarkable. The comparatively rational Ti content of UNS S44100 ferritic stainless steel for meeting the requirements of investment casting production is between 0.10 and 0.20 wt%.

  15. Changes in measured size of atherosclerotic plaque calcifications in dual-energy CT of ex vivo carotid endarterectomy specimens: effect of monochromatic keV image reconstructions

    International Nuclear Information System (INIS)

    Mannelli, Lorenzo; Mitsumori, Lee M.; Ferguson, Marina; Xu, Dongxiang; Chu, Baocheng; Branch, Kelley R.; Shuman, William P.; Yuan, Chun

    2013-01-01

    The aim of this study was to compare the size of the calcifications measured on the different keV images to a histological standard. Five ex vivo carotid endarterectomy (CEA) specimens were imaged with a dual-energy CT. CT images were reconstructed at different monochromatic spectral energies (40, 60, 77, 80, 100, 120, 140 keV). Cross-sectional area of the plaque calcifications present on each CT image was measured. The histological calcium areas on each corresponding CEA specimen were traced manually on digitised images of Toluidine Blue/Basic Fuchsin stained plastic sections. The CT images and corresponding histology sections were matched. The CT-derived calcium areas on each keV image were compared to the calcified area measurements by histology. A total of 107 histology sections were matched to corresponding CT images. The average calcified area per section by histology was 7.6 ± 7 mm 2 (range 0-26.4 mm 2 ). There was no significant difference between the calcified areas measured by histology and those measured on CT-virtual monochromatic spectral (VMS) reconstructed images at 77 keV (P = 0.08), 80 keV (P = 0.20) and 100 keV (P = 0.14). Calcium area measured on the 80 keV image set was most comparable to the amount of calcium measured by histology. (orig.)

  16. Specimen Machining for the Study of the Effect of Swelling on CGR in PWR Environment.

    Energy Technology Data Exchange (ETDEWEB)

    Teysseyre, Sebastien Paul [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-06-01

    This report describes the preparation of ten specimens to be used for the study of the effect of swelling on the propagation of irradiation assisted stress corrosion cracking cracks. Four compact tension specimens, four microscopy plates and two tensile specimens were machined from a AISI 304 material that was irradiated up to 33 dpa. The specimens had been machined such as to represent the behavior of materials with 3.7%swelling and <2% swelling.

  17. Finite Element Analysis for Bending Process of U-Bending Specimens

    Energy Technology Data Exchange (ETDEWEB)

    Park, Won Dong; Bahn, Chi Bum [Pusan National University, Busan (Korea, Republic of)

    2015-10-15

    ASTM G30 suggests that the applied strain can be calculated by dividing thickness by a bend radius. It should be noted, however, that the formula is reliable under an assumption that the ratio of thickness to bend radius is less than 0.2. Typically, to increase the applied stress/strain, the ratio of thickness to bend radius becomes larger than 0.2. This suggests that the estimated strain values by ASTM G30 are not reliable to predict the actual residual strain state of the highly deformed U-bend specimen. For this reason, finite element analysis (FEA) for the bending process of Ubend specimens was conducted by using a commercial finite element analysis software ABAQUS. ver.6.14- 2;2014. From the results of FEA, PWSCC initiation time and U-bend specimen size can be determined exactly. Since local stress and strain have a significant effect on the initiation of PWSCC, it was inappropriate to apply results of ASTM G30 to the PWSCC test directly. According to results of finite element analysis (FEA), elastic relaxation can cause inaccuracy in intended final residual stress. To modify this inaccuracy, additional process reducing the spring back is required. However this additional process also may cause uncertainty of stress/strain state. Therefore, the U-bending specimen size which is not creating uncertainty should be optimized and selected. With the bending radius of 8.3 mm, the thickness of 3 mm and the roller distance of 32.6 mm, calculated maximum stress and strain were 670 MPa and 0.21, respectively.

  18. The effect of shredding and test apparatus size on compressibility and strength parameters of degraded municipal solid waste.

    Science.gov (United States)

    Hossain, M S; Gabr, M A; Asce, F

    2009-09-01

    In many situations, MSW components are processed and shredded before use in laboratory experiments using conventional soil testing apparatus. However, shredding MSW material may affect the target property to be measured. The objective of this study is to contribute to the understanding of the effect of shredding of MSW on the measured compressibility and strength properties. It is hypothesized that measured properties can be correlated to an R-value, the ratio of waste particle size to apparatus size. Results from oedometer tests, conducted on 63.5 mm, 100 mm, 200 mm diameter apparatus, indicated the dependency of the compressibility parameters on R-value. The compressibility parameters are similar for the same R-value even though the apparatus size varies. The results using same apparatus size with variable R-values indicated that shredding of MSW mainly affects initial compression. Creep and biological strain rate of the tested MSW are not significantly affected by R-value. The shear strength is affected by shredding as the light-weight reinforcing materials are shredded into smaller pieces during specimen preparation. For example, the measured friction angles are 32 degrees and 27 degrees for maximum particle sizes of 50 mm and 25 mm, respectively. The larger MSW components in the specimen provide better reinforcing contribution. This conclusion is however dependent on comparing specimen at the same level of degradation since shear strength is also a function of extent of degradation.

  19. Geometrical size effect in high cycle fatigue strength of heavy-walled Ductile Cast Iron GJS400: Weakest link vs. defect-based approach

    Directory of Open Access Journals (Sweden)

    Cova Matteo

    2014-06-01

    Full Text Available Fatigue strength is known to decrease with increasing dimension of the component. This is due to a technological size effect, related to the production process, and to a geometrical size effect, due to a higher probability of finding a large defect. To investigate the latter, an heavy-walled component made of Ductile Cast Iron (DCI has been trepanned and a fatigue test plan has been carried out using 4 different specimen geometries. An attempt has been made to relate the resulting fatigue strength using a weakest-link approach based on the effective volumes and surfaces. This approach seems to work well only in cases of different specimen's lengths. Some of the fracture surfaces were analyzed by means of SEM and the initiating defects were identified and measured. An approach in which the defects population can be randomly distributed in the specimen has been tried. Virtual fatigue tests have been carried out by considering pure propagation of the worst defect. The resulting fatigue curves showed that this approach is promising but needs further description of the initiation phase.

  20. SMILE: test to validate the WPS effect with a cylindrical thick-walled specimen

    International Nuclear Information System (INIS)

    Bezdikian, G.; Moinereau, D.; Roos, E.; Kerkhof, K.; Taylor, N.

    2004-01-01

    The Reactor Pressure Vessel (RPV) is an essential component, which is liable to limit the lifetime duration of PWR plants. The assessment of defects in RPV subjected to pressurized thermal shock (PTS) transients made at an European level generally does not necessarily consider the beneficial effect of the load history (Warm Pre-stress, WPS). The SMILE project - Structural Margin Improvements in aged embrittled RPV with Load history Effects - aims to give sufficient elements to demonstrate, to model and to validate the beneficial WPS effect. It also aims to harmonize the different approaches in the national codes and standards regarding the inclusion of the WPS effect in a RPV structural integrity assessment. The project includes significant experimental work on WPS type experiments with C(T) specimens and a PTS type transient experiment on a large component. This paper deals with the results of the PTS type transient experiment on a component-like, specimen subjected to WPS-loading, the so called Validation Test, carried out within the framework of work package WP4. The test specimen consists of a cylindrical thickwalled specimen with a thickness of 40 mm and an outer diameter of 160 mm, provided with an internal fully circumferential crack with a depth of about 15 mm. The specified load path type is Load-Cool-Unload-Fracture (LCUF). (orig.)

  1. Imaging of concrete specimens using inverse synthetic aperture radar

    International Nuclear Information System (INIS)

    Rhim, Hong C.; Buyukozturk, Oral

    2000-01-01

    Radar Measurement results of laboratory size concrete specimens are presented in this paper. The purpose of this research work is to study various aspects of the radar method in an effort to develop an improved radar system for nondestructive testing of concrete structures. The radar system used for the study is an Inverse Synthetic Aperture Radar (ISAR), which is capable of transmitting microwaves at three different frequency ranges of 2-3.4, 3.4-5.8, and 8-12 GHz. Radar measurement setup is such that the radar is locates 14.4 m away from a concrete target to satisfy a far-field criterion. The concrete target is rotated for 20 degrees during the measurements for the generation of two-dimensional (cross-range) imagery. Concrete targets used for the measurements have the dimensions of 305 mm (width)x305 mm (height)x92 mm (thickness) with different inside configurations. Comparisons are made for dry and wet specimens, specimens with and without inclusions. Each specimen is made to model various situations that a concrete structure can have in reality. Results show that center frequency, frequency bandwidth, and polarization of the incident wave have different effects on identifying the thickness or inclusions inside concrete specimens. Results also suggest that a certain combination of measurement parameters is suitable for a specific application area. Thus, measurement parameters can be optimized for a specific problem. The findings are presented and discussed in details in the paper. Signal processing schemes implemented for imaging of the specimens are also discussed

  2. Effect of grain size on superelasticity in Fe-Mn-Al-Ni shape memory alloy wire

    Directory of Open Access Journals (Sweden)

    T. Omori

    2013-09-01

    Full Text Available Effects of grain size on superelastic properties in Fe-34Mn-15Al-7.5Ni alloy wires with a ⟨110⟩ fiber-texture were investigated by cyclic tensile tests. It was confirmed that the critical stress for induced martensitic transformation and the superelastic strain are functions of relative grain size d/D (d: mean grain diameter, D: wire diameter, and that the critical stress is proportional to (1–d/D2 as well as in Cu-based shape memory alloys. A large superelastic strain of about 5% was obtained in the specimen with a large relative grain size over d/D = 1.

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

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, A.

    2004-01-01

    . The onset of cleavage is taken to occur when the average of the maximum principal stress over a specified volume attains a critical value. The weld analyzed here is overmatched, so that the yield strength for the weld is larger than that of the base material. Analyses are carried out for specimens where...... the notch is cut parallel to the surface of the test piece, as well as more complex geometries where the notched surface of the specimen is rotated relative to the surface of the test piece. It is found that even for a homogeneous material the brittle-ductile transition can be much affected by three...... dimensional effects; for example, curvature of the deformed free surface gives rise to a stress increase that promotes cleavage. Furthermore, for the rotated specimens the weld geometry relative to the notched specimen surface is so complex that only a full 3D analysis is able to account for the interaction...

  4. Eddy current crack detection capability assessment approach using crack specimens with differing electrical conductivity

    Science.gov (United States)

    Koshti, Ajay M.

    2018-03-01

    Like other NDE methods, eddy current surface crack detectability is determined using probability of detection (POD) demonstration. The POD demonstration involves eddy current testing of surface crack specimens with known crack sizes. Reliably detectable flaw size, denoted by, a90/95 is determined by statistical analysis of POD test data. The surface crack specimens shall be made from a similar material with electrical conductivity close to the part conductivity. A calibration standard with electro-discharged machined (EDM) notches is typically used in eddy current testing for surface crack detection. The calibration standard conductivity shall be within +/- 15% of the part conductivity. This condition is also applicable to the POD demonstration crack set. Here, a case is considered, where conductivity of the crack specimens available for POD testing differs by more than 15% from that of the part to be inspected. Therefore, a direct POD demonstration of reliably detectable flaw size is not applicable. Additional testing is necessary to use the demonstrated POD test data. An approach to estimate the reliably detectable flaw size in eddy current testing for part made from material A using POD crack specimens made from material B with different conductivity is provided. The approach uses additional test data obtained on EDM notch specimens made from materials A and B. EDM notch test data from the two materials is used to create a transfer function between the demonstrated a90/95 size on crack specimens made of material B and the estimated a90/95 size for part made of material A. Two methods are given. For method A, a90/95 crack size for material B is given and POD data is available. Objective of method A is to determine a90/95 crack size for material A using the same relative decision threshold that was used for material B. For method B, target crack size a90/95 for material A is known. Objective is to determine decision threshold for inspecting material A.

  5. Assessment of plastic flow and fracture properties with small specimens test techniques for IFMIF-designed specimens

    International Nuclear Information System (INIS)

    Spaetig, P.; Campitelli, E.N.; Bonade, R.; Baluc, N.

    2005-01-01

    The primary mission of the International Fusion Material Irradiation Facility (IFMIF) is to generate a material database to be used for the design of various components, for the licensing and for the assessment of the safe operation of a demonstration fusion reactor. IFMIF is an accelerator-based high-energy neutron source whose irradiation volume is quite limited (0.5 l for the high fluence volume). This requires the use of small specimens to measure the irradiation-induced changes on the physical and mechanical properties of materials. In this paper, we developed finite element models to better analyze the results obtained with two different small specimen test techniques applied to the tempered martensitic steel F82H-mod. First, one model was used to reconstruct the load-deflection curves of small ball punch tests, which are usually used to extract standard tensile parameters. It was shown that a reasonable assessment of the overall plastic flow can be done with small ball punch tests. Second, we investigated the stress field sensitivity at a crack tip to the constitutive behavior, for a crack modeled in plane strain, small-scale yielding and fracture mode I conditions. Based upon a local criterion for cleavage, that appears to be the basis to account for the size and geometry effects on fracture toughness, we showed that the details of the constitutive properties play a key role in modeling the irradiation-induced fracture toughness changes. Consequently, we suggest that much more attention and efforts have to be paid in investigating the post-yield behavior of the irradiated specimens and, in order to reach this goal, we recommend the use of not only tensile specimens but also that of compression ones in the IFMIF irradiation matrices. (author)

  6. Full thickness crack arrest investigations on compact specimens and a heavy wide-plate

    International Nuclear Information System (INIS)

    Kussmaul, K.; Gillot, R.; Elenz, T.

    1993-01-01

    In order to determine the influence of specimen size and testing procedure on the crack arrest toughness K Ia at various temperatures, investigations were carried out on a wide-plate and compact specimens using a highly brittle material. Test interpretation included static as well as dynamic methods. The comparison of the measured K Ia -values shows good agreement although there is a distinct difference in specimen size. In general, the (static) ASTM test method yields a lower and thus conservative estimate of the crack arrest toughness K Ia . 14 refs., 27 figs., 3 tabs

  7. The effect of residual stresses induced by prestraining on fatigue life of notched specimens

    Science.gov (United States)

    Sadeler, R.; Ozel, A.; Kaymaz, I.; Totik, Y.

    2005-06-01

    The effect of tensile prestraining-induced residual stress on the fatigue life of notched steel parts was investigated. The study was performed on AISI 4140 steel. Rotating bending fatigue tests were carried out on semicircular notched specimens with different notch radii in the as-quenched and tempered conditions. Metallography of the specimens was performed by means of light optical microscopy. The finite-element method was used to evaluate the residual stress distribution near the notch region. Fatigue tests revealed fatigue life improvement for notched specimens, which changes depending on the notch radii and applied stress. Scanning electron microscopy was used to examine the fracture surfaces of the specimens.

  8. Size effects in tin-based lead-free solder joints: Kinetics of bond formation and mechanical characteristics

    Science.gov (United States)

    Abdelhadi, Ousama Mohamed Omer

    Continuous miniaturization of microelectronic interconnects demands smaller joints with comparable microstructural and structural sizes. As the size of joints become smaller, the volume of intermetallics (IMCs) becomes comparable with the joint size. As a result, the kinetics of bond formation changes and the types and thicknesses of IMC phases that form within the constrained region of the bond varies. This dissertation focuses on investigating combination effects of process parameters and size on kinetics of bond formation, resulting microstructure and the mechanical properties of joints that are formed under structurally constrained conditions. An experiment is designed where several process parameters such as time of bonding, temperature, and pressure, and bond thickness as structural chracteristic, are varied at multiple levels. The experiment is then implemented on the process. Scanning electron microscope (SEM) is then utilized to determine the bond thickness, IMC phases and their thicknesses, and morphology of the bonds. Electron backscatter diffraction (EBSD) is used to determine the grain size in different regions, including the bulk solder, and different IMC phases. Physics-based analytical models have been developed for growth kinetics of IMC compounds and are verified using the experimental results. Nanoindentation is used to determine the mechanical behavior of IMC phases in joints in different scales. Four-point bending notched multilayer specimen and four-point bending technique were used to determine fracture toughness of the bonds containing IMCs. Analytical modeling of peeling and shear stresses and fracture toughness in tri-layer four-point bend specimen containing intermetallic layer was developed and was verified and validated using finite element simulation and experimental results. The experiment is used in conjunction with the model to calculate and verify the fracture toughness of Cu6Sn5 IMC materials. As expected two different IMC phases

  9. Correlation of fracture parameters during onset of crack in middle tension specimen

    Directory of Open Access Journals (Sweden)

    M.S. Starvin

    2017-07-01

    Full Text Available The present study addresses the implementation of finite element analysis and the prediction of fracture parameters in a middle tension (MT specimen that was fabricated using AISI 4140 steel. The correlation of fracture parameters with external loads and crack sizes was investigated. A Finite Element code was developed to simulate the fracture model. The contour integral method was applied in the calculation of stress intensity factor and J-integral in the cracked specimen. The ASTM standard empirical formula was used to calculate the stress intensity factor (SIF and the numerical predictions were validated. A standard laboratory experiment was also carried out using the MT specimen to calculate the crack growth rate in this specific material. The SIF values were almost linear with external load but it was decreasing as the crack size increases. The crack requires minimum load for crack propagation as the crack size increases. Similarly the J-integral was accelerated with increase in crack size.

  10. A Rapid and Cost-Effective Method for DNA Extraction from Archival Herbarium Specimens.

    Science.gov (United States)

    Krinitsina, A A; Sizova, T V; Zaika, M A; Speranskaya, A S; Sukhorukov, A P

    2015-11-01

    Here we report a rapid and cost-effective method for the extraction of total DNA from herbarium specimens up to 50-90-year-old. The method takes about 2 h, uses AMPure XP magnetic beads diluted by PEG-8000- containing buffer, and does not require use of traditional volatile components like chloroform, phenol, and liquid nitrogen. It yields up to 4 µg of total nucleic acid with high purity from about 30 mg of dry material. The quality of the extracted DNA was tested by PCR amplification of 5S rRNA and rbcL genes (nuclear and chloroplast DNA markers) and compared against the traditional chloroform/isoamyl alcohol method. Our results demonstrate that the use of the magnetic beads is crucial for extraction of DNA suitable for subsequent PCR from herbarium samples due to the decreasing inhibitor concentrations, reducing short fragments of degraded DNA, and increasing median DNA fragment sizes.

  11. Size Effect Studies of the Creep Behaviour of 20MnMoNi55 at Temperatures from 700 oC to 900 oC

    International Nuclear Information System (INIS)

    Krompholz, K.; Groth, E.; Kalkhof, D.

    2000-11-01

    One of the objectives of the REVISA project (REactor Vessel Integrity in Severe Accidents) is to assess size and scale effects in plastic flow and failure. This includes an experimental programme devoted to characterising the influence of specimen size, strain rate, and strain gradients at various temperatures. One of the materials selected was the forged reactor pressure vessel material 20 MnMoNi 55, material number 1.6310 (heat number 69906). Among others, a size effect study of the creep response of this material was performed, using geometrically similar smooth specimens with 5 mm and 20 mm diameter. The tests were done under constant load in an inert atmosphere at 700 o C, 800 o C, and 900 o C, close to and within the phase transformation regime. The mechanical stresses varied from 10 MPa to 30 MPa, depending on temperature. Prior to creep testing the temperature and time dependence of scale oxidation as well as the temperature regime of the phase transformation was determined. The creep tests were supplemented by metallographical investigations.The test results are presented in form of creep curves strain versus time from which characteristic creep data were determined as a function of the stress level at given temperatures. The characteristic data are the times to 5% and 15% strain and to rupture, the secondary (minimum) creep rate, the elongation at fracture within the gauge length, the type of fracture and the area reduction after fracture. From metallographical investigations the austenitic phase contents at different temperatures could be estimated. From these data also the parameters of the regression calculation (e.g. Norton's creep law) were obtained. The evaluation revealed that the creep curves and characteristic data are size dependent of varying degree, depending on the stress and temperature level, but the size influence cannot be related to corrosion or orientation effects or to macroscopic heterogeneity (position effect) of the original

  12. Use of globally unique identifiers (GUIDs) to link herbarium specimen records to physical specimens.

    Science.gov (United States)

    Nelson, Gil; Sweeney, Patrick; Gilbert, Edward

    2018-02-01

    With the advent of the U.S. National Science Foundation's Advancing Digitization of Biodiversity Collections program and related worldwide digitization initiatives, the rate of herbarium specimen digitization in the United States has expanded exponentially. As the number of electronic herbarium records proliferates, the importance of linking these records to the physical specimens they represent as well as to related records from other sources will intensify. Although a rich and diverse literature has developed over the past decade that addresses the use of specimen identifiers for facilitating linking across the internet, few implementable guidelines or recommended practices for herbaria have been advanced. Here we review this literature with the express purpose of distilling a specific set of recommendations especially tailored to herbarium specimen digitization, curation, and management. We argue that associating globally unique identifiers (GUIDs) with physical herbarium specimens and including these identifiers in all electronic records about those specimens is essential to effective digital data curation. We also address practical applications for ensuring these associations.

  13. 3D volume reconstruction from serial breast specimen radiographs for mapping between histology and 3D whole specimen imaging

    NARCIS (Netherlands)

    Mertzanidou, T.; Hipwell, J.H.; Reis, S.; Hawkes, D.J.; Ehteshami Bejnordi, B.; Dalmis, M.U.; Vreemann, S.; Platel, B.; Laak, J.A. van der; Karssemeijer, N.; Hermsen, M.; Bult, P.; Mann, R.M.

    2017-01-01

    PURPOSE: In breast imaging, radiological in vivo images, such as x-ray mammography and magnetic resonance imaging (MRI), are used for tumor detection, diagnosis, and size determination. After excision, the specimen is typically sliced into slabs and a small subset is sampled. Histopathological

  14. Application of small specimens to fracture mechanics characterization of irradiated pressure vessel steels

    International Nuclear Information System (INIS)

    Sokolov, M.A.; Wallin, K.; McCabe, D.E.

    1996-01-01

    In this study, precracked Charpy V-notch (PCVN) specimens were used to characterize the fracture toughness of unirradiated and irradiated reactor pressure vessel steels in the transition region by means of three-point static bending. Fracture toughness at cleavage instability was calculated in terms of elastic-plastic K Jc values. A statistical size correction based upon weakest-link theory was performed. The concept of a master curve was applied to analyze fracture toughness properties. Initially, size-corrected PCVN data from A 533 grade B steel, designated HSST Plate O2, were used to position the master curve and a 5% tolerance bound for K Jc data. By converting PCVN data to IT compact specimen equivalent K Jc data, the same master curve and 5% tolerance bound curve were plotted against the Electric Power Research Institute valid linear-elastic K Jc database and the ASME lower bound K Ic curve. Comparison shows that the master curve positioned by testing several PCVN specimens describes very well the massive fracture toughness database of large specimens. These results give strong support to the validity of K Jc with respect to K Ic in general and to the applicability of PCVN specimens to measure fracture toughness of reactor vessel steels in particular. Finally, irradiated PCVN specimens of other materials were tested, and the results are compared to compact specimen data. The current results show that PCVNs demonstrate very good capacity for fracture toughness characterization of reactor pressure vessel steels. It provides an opportunity for direct measurement of fracture toughness of irradiated materials by means of precracking and testing Charpy specimens from surveillance capsules. However, size limits based on constraint theory restrict the operational test temperature range for K Jc data from PCVN specimens. 13 refs., 8 figs., 1 tab

  15. Fracture toughness evaluation of Eurofer'97 by testing small specimens

    International Nuclear Information System (INIS)

    Serrano, M.; Fernandez, P.; Lapena, J.

    2006-01-01

    The Eurofer'97 is the structural reference material that will be tested in the ITER modules. Its metallurgical properties have been well characterized during the last years. However, more investigations related with the fracture toughness of this material are necessary because this property is one of the most important to design structural components and to study their integrity assessment. In the case of structural materials for fusion reactor the small specimen technology (SSTT) are being actively developed to investigate the fracture toughness among other mechanical properties. The use of small specimens is due to the small available irradiation volume of IFMIF and also due to the high fluence expected in the fusion reactor. The aim of this paper is to determine the fracture toughness of the Eurofer'97 steel by testing small specimens of different geometry in the ductile to brittle transition region, with the application of the Master Curve methodology, and to evaluate this method to assess the decrease in fracture toughness due to neutron irradiation. The tests and data analysis have been performed following the Master Curve approach included in the ASTM Standard E1921-05. Specimen size effect and comparison of the fracture toughness results with data available in the literature are also considered. (author)

  16. Enhanced radiometric detection of Mycobacterium paratuberculosis by using filter-concentrated bovine fecal specimens

    International Nuclear Information System (INIS)

    Collins, M.T.; Kenefick, K.B.; Sockett, D.C.; Lambrecht, R.S.; McDonald, J.; Jorgensen, J.B.

    1990-01-01

    A commercial radiometric medium, BACTEC 12B, was modified by addition of mycobactin, egg yolk suspension, and antibiotics (vancomycin, amphotericin B, and nalidixic acid). Decontaminated bovine fecal specimens were filter concentrated by using 3-microns-pore-size, 13-mm-diameter polycarbonate filters, and the entire filter was placed into the radiometric broth. Comparison of the radiometric technique with conventional methods on 603 cattle from 9 Mycobacterium paratuberculosis-infected herds found that of 75 positive specimens, the radiometric technique detected 92% while conventional methods detected 60% (P less than 0.0005). Only 3.9% of radiometric cultures were contaminated. To measure the effect of filter concentration of specimens on the detection rate, 5 cattle with minimal and 5 with moderate ileum histopathology were sampled weekly for 3 weeks. M. paratuberculosis was detected in 33.3% of nonfiltered specimens and 76.7% of filtered specimens (P less than 0.005). Detection rates were directly correlated with the severity of disease, and the advantage of specimen concentration was greatest on fecal specimens from cattle with low-grade infections. Detection times were also correlated with infection severity: 13.4 +/- 5.9 days with smear-positive specimens, 27.9 +/- 8.7 days with feces from cows with typical subclinical infections, and 38.7 +/- 3.8 days with fecal specimens from cows with low-grade infections. Use of a cocktail of vancomycin, amphotericin B, and nalidixic acid for selective suppression of nonmycobacterial contaminants was better than the commercial product PANTA (Becton Dickinson Microbiologic Systems, Towson, Md.) only when specimens contained very low numbers of M. paratuberculosis

  17. Observation particle morphology of colloidal system by conventional SEM with an improved specimen preparation technique.

    Science.gov (United States)

    Xu, Jing; Hou, Zhaosheng; Yuan, Xiaojiao; Guo, Hong

    2011-08-01

    On the basis of our previous report that polymer emulsion with different viscosity can be investigated by conventional scanning electron microscopy (SEM), we have developed an improved specimen preparation technique for obtaining particle morphology and size of colloidal silver, collagen, glutin, and polymer microspheres. In this study, we expect to provide a means for charactering the three-dimensional surface microstructure of colloidal particles. Dilution of the samples with appropriate volatile solvent like ethanol is effective for SEM specimen preparation. At a proper ratio between sample and ethanol, the colloidal particles are dispersed uniformly in ethanol and then deposited evenly on the substrate. Different drying methods are studied to search a proper drying condition, in which the small molecule solvent is removed without destroying the natural particle morphology. And the effects of ethanol in the specimen preparation process are described by analyzing the physicochemical properties of ethanol. The specimen preparation technique is simple and can be achieved in common laboratory for charactering the particle morphology of colloidal system. Copyright © 2010 Wiley-Liss, Inc.

  18. Conclusions regarding fracture mechanics testing and evaluation of small specimens - As evidenced by the finnish contribution to the IAEA CRP3 programme

    Energy Technology Data Exchange (ETDEWEB)

    Wallin, K; Valo, M; Rintamaa, R; Torronen, K [Technical Research Centre of Finland, Espoo (Finland); Ahlstrand, R [Imatran Voima Oy (IVO), Helsinki (Finland)

    1994-12-31

    An extensive mechanical property evaluation has been carried out on various specimens (a Japanese steel plate (JRQ), a French forging material (FFA) and a Japanese forging material (JFL)) in the as-received and irradiated conditions. The mechanical properties measured at different temperatures include Charpy-V notch and instrumented pre-cracked Charpy data and static and dynamic elastic-plastic fracture toughness based on the J-integral, with various specimen size and geometry. Test analysis lead to conclusions regarding the use of small specimen fracture mechanical tests for investigating irradiation effects: CVN{sub pc} and RCT type specimens are suitable for determining the materials fracture toughness even in the ductile/brittle transition region provided the elastic-plastic parameter K{sub JC} is applied together with a statistical size correction. These two specimen types yield equivalent results for the fracture toughness transition shift. Charpy-V appears not to be suitable for estimating the static fracture toughness transition shift. 8 refs., 11 figs.

  19. Size Effect Studies of the Creep Behaviour of 20MnMoNi55 at Temperatures from 700 {sup o}C to 900 {sup o}C

    Energy Technology Data Exchange (ETDEWEB)

    Krompholz, K.; Groth, E.; Kalkhof, D

    2000-11-01

    One of the objectives of the REVISA project (REactor Vessel Integrity in Severe Accidents) is to assess size and scale effects in plastic flow and failure. This includes an experimental programme devoted to characterising the influence of specimen size, strain rate, and strain gradients at various temperatures. One of the materials selected was the forged reactor pressure vessel material 20 MnMoNi 55, material number 1.6310 (heat number 69906). Among others, a size effect study of the creep response of this material was performed, using geometrically similar smooth specimens with 5 mm and 20 mm diameter. The tests were done under constant load in an inert atmosphere at 700 {sup o}C, 800 {sup o}C, and 900 {sup o}C, close to and within the phase transformation regime. The mechanical stresses varied from 10 MPa to 30 MPa, depending on temperature. Prior to creep testing the temperature and time dependence of scale oxidation as well as the temperature regime of the phase transformation was determined. The creep tests were supplemented by metallographical investigations.The test results are presented in form of creep curves strain versus time from which characteristic creep data were determined as a function of the stress level at given temperatures. The characteristic data are the times to 5% and 15% strain and to rupture, the secondary (minimum) creep rate, the elongation at fracture within the gauge length, the type of fracture and the area reduction after fracture. From metallographical investigations the austenitic phase contents at different temperatures could be estimated. From these data also the parameters of the regression calculation (e.g. Norton's creep law) were obtained. The evaluation revealed that the creep curves and characteristic data are size dependent of varying degree, depending on the stress and temperature level, but the size influence cannot be related to corrosion or orientation effects or to macroscopic heterogeneity (position effect) of

  20. Extreme value paradigm for the effect of size of target volume on end results in radiation oncology

    International Nuclear Information System (INIS)

    Herbert, D.E.

    1983-01-01

    In clinical radiation oncology, it is commonly reported that complications of normal tissue occur more readily at larger field sizes for a given dose and recurrence of disease is observed more frequently from the larger tumors for a given dose. Cognate phenomena have long been observed in the study of the strength of materials. That is, the larger specimens will fracture under less applied stress, breakdown under less applied voltage, corrode in a shorter time, etc. The statistical theory of extreme values has provided both a rational explanation and a technique for exploitation of these ''size effects'' on the likelihood of specimen failure. This theory describes the relation which exists between the parameters (in particular, the location parameter) of the frequency distributions of the extreme values [smallest x(1) and largest x(n)] in a sample from a population of observations xi and the sample size n. It is shown in the present paper that the clinical failure phenomena are not inconsistent with the statistical theory of extreme values. The paper presents heuristic comparisons of the predictions of this theory with the received clinical observations of the effect of the size of the volume of irradiated tissues on the likelihood of occurrence of the misadventures of clinical radiation oncology: recurrence of disease and complication of normal tissue. The concordance of observations and predictions is acceptable. The quality and quantity of the currently available data have precluded the construction of any apodictic representations

  1. Correlations between Standard and Miniaturised Charpy-V Specimens

    International Nuclear Information System (INIS)

    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

  2. Robust DNA Isolation and High-throughput Sequencing Library Construction for Herbarium Specimens.

    Science.gov (United States)

    Saeidi, Saman; McKain, Michael R; Kellogg, Elizabeth A

    2018-03-08

    Herbaria are an invaluable source of plant material that can be used in a variety of biological studies. The use of herbarium specimens is associated with a number of challenges including sample preservation quality, degraded DNA, and destructive sampling of rare specimens. In order to more effectively use herbarium material in large sequencing projects, a dependable and scalable method of DNA isolation and library preparation is needed. This paper demonstrates a robust, beginning-to-end protocol for DNA isolation and high-throughput library construction from herbarium specimens that does not require modification for individual samples. This protocol is tailored for low quality dried plant material and takes advantage of existing methods by optimizing tissue grinding, modifying library size selection, and introducing an optional reamplification step for low yield libraries. Reamplification of low yield DNA libraries can rescue samples derived from irreplaceable and potentially valuable herbarium specimens, negating the need for additional destructive sampling and without introducing discernible sequencing bias for common phylogenetic applications. The protocol has been tested on hundreds of grass species, but is expected to be adaptable for use in other plant lineages after verification. This protocol can be limited by extremely degraded DNA, where fragments do not exist in the desired size range, and by secondary metabolites present in some plant material that inhibit clean DNA isolation. Overall, this protocol introduces a fast and comprehensive method that allows for DNA isolation and library preparation of 24 samples in less than 13 h, with only 8 h of active hands-on time with minimal modifications.

  3. Effectiveness of Plastinated Anatomical Specimens Depicting Common Sports Injuries to Enhance Musculoskeletal Injury Evaluation Education

    Science.gov (United States)

    Tamura, Kaori; Stickley, Christopher D.; Labrash, Steven J.; Lozanoff, Scott

    2014-01-01

    Context: Plastination techniques have emerged as effective methods for preserving human tissue and enabling human specimens to be utilized in a fashion similar to anatomical models with much greater accuracy. Opportunities to observe and experience human specimens in classroom settings should be beneficial to undergraduate and graduate students in…

  4. Numerical investigation of 3-D constraint effects on brittle fracture in SE(B) and C(T) specimens

    International Nuclear Information System (INIS)

    Nevalainen, M.; Dodds, R.H. Jr.

    1996-07-01

    This investigation employs 3-D nonlinear finite element analyses to conduct an extensive parametric evaluation of crack front stress triaxiality for deep notch SE(B) and C(T) specimens and shallow notch SE(B) specimens, with and without side grooves. Crack front conditions are characterized in terms of J-Q trajectories and the constraint scaling model for cleavage fracture toughness proposed previously by Dodds and Anderson. The 3-D computational results imply that a significantly less strict size/deformation limit, relative to the limits indicated by previous plane-strain computations, is needed to maintain small-scale yielding conditions at fracture by a stress- controlled, cleavage mechanism in deep notch SE(B) and C(T) specimens. Additional new results made available from the 3-D analyses also include revised η-plastic factors for use in experimental studies to convert measured work quantities to thickness average and maximum (local) J-values over the crack front

  5. Experimental investigation of grain size effect on fatigue crack growth rate in turbine disc superalloy GH4169 under different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Dianyin [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China); Collaborative Innovation Center of Advanced Aero-Engine, Beijing 100191 (China); Beijing Key Laboratory of Aero-Engine Structure and Strength, Beijing 100191 (China); Mao, Jianxing [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China); Song, Jun, E-mail: jun.song2@mcgill.ca [Mining and Materials Engineering, McGill University, Montreal, QC, Canada H3A 0C5 (Canada); Meng, Fanchao [Mining and Materials Engineering, McGill University, Montreal, QC, Canada H3A 0C5 (Canada); Shan, Xiaoming [China Aviation Powerplant Research Institute, Zhuzhou 412002 (China); Wang, Rongqiao, E-mail: wangrq@buaa.edu.cn [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China); Collaborative Innovation Center of Advanced Aero-Engine, Beijing 100191 (China); Beijing Key Laboratory of Aero-Engine Structure and Strength, Beijing 100191 (China)

    2016-07-04

    Systematic experiments for fatigue crack growth (FCG) rate on compact tension (CT) specimens have been conducted in nickel-based superalloy GH4169 at a broad range of temperatures with a frequency of 10 Hz and a stress ratio of 0.1. In order to investigate the crack closure behavior, FCG experiments at stress ratio of 0.5 were also performed by comparing with the results at stress ration of 0.1. CT specimens were cut from three typical locations of an actual forged turbine disc to investigate the effect of grain size on the FCG behaviors. The grain size distribution, precipitates and fracture surface characteristics at different locations of the turbine disc were examined through optical microscope, transmission electron microscope (TEM) and scanning electronic microscope (SEM) analyses. Digital image correlation (DIC), optical interferometry and oxide film measurements were carried out to investigate the presence and inducement of the crack closure. Then a modified FCG model, with a distribution factor that evaluates the scattering in the FCG rate, was formulated to describe the dependence of FCG rate on grain size. Finally, the possible microscopic mechanisms to explain the grain size effect on the FCG behaviors based on crack deflection and blockage, and the crack closure inducements involving plasticity and oxide were discussed in this study.

  6. Thermal analysis on the specimens for low irradiation temperature below 100degC in the HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Myoung-Hwan; Kim, Bong-Goo; Lee, Byung-Chul; Kim, Tae-Kyu [Korea Atomic Energy Research Inst., Daejeon (Korea, Republic of)

    2012-03-15

    A capsule has been used for an irradiation test of various nuclear materials in the research reactor, HANARO. As a part of the research reactor development project with a plate type fuel, the irradiation tests of beryllium, zircaloy-4 and graphite materials using the capsule will be carried out to obtain the mechanical characteristics at low temperatures below 100degC with 30 MW reactor power. In this study, in order to obtain the preliminary design data of the capsule with various specimens and the temperature of specimens, a thermal analysis is performed by using an ANSYS program. The finite element models for the cross section of the capsule containing the specimen are generated, and the temperatures are evaluated. The analysis results show that most specimens meet the irradiation target temperature. However, some canned graphite specimens have a slightly high temperature, and the gap size has a significant effect on the specimen temperature. Based on those results a detailed design and analysis of the capsule will be completed this year. (author)

  7. Analysis of the Indentation Size Effect in the Microhardness Measurements in B6O

    Directory of Open Access Journals (Sweden)

    Ronald Machaka

    2011-01-01

    Full Text Available The Vickers microhardness measurements of boron suboxide (B6O ceramics prepared by uniaxial hot-pressing was investigated at indentation test loads in the range from 0.10 to 2.0 kgf. Results from the investigation indicate that the measured microhardness exhibits an indentation load dependence. Based on the results, we present a comprehensive model intercomparison study of indentation size effects (ISEs in the microhardness measurements of hot-pressed B6O discussed using existing models, that is, the classical Meyer's law, Li and Bradt's proportional specimen resistance model (PSR, the modified proportional specimen resistance model (MPSR, and Carpinteri's multifractal scaling law (MFSL. The best correlation between literature-cited load-independent Vickers microhardness values, the measured values, and applied models was achieved in the case of the MPSR and the MFSL models.

  8. Effect of Heat Flux on the Specimen Temperature of an LBE Capsule

    International Nuclear Information System (INIS)

    Kang, Y. H.; Park, S. J.; Cho, M. S.; Choo, K. N.; Lee, Y. S.

    2011-01-01

    For application of high-temperature irradiation tests in the HANARO reactor for Gen IV reactor material development, a number of newly designed LBE capsules have been investigated at KAERI since 2008. Recent study on heat transfer experiment of an LBE capsule with a single heater has shown that the specimen temperature of the mock-up increased linearly with an increase of heat input. The work highlighted only the heat transfer capability of an LBE capsule with a single heater as a simulated specimen in a liquid metal medium. Hence, a new LBE capsule with multi specimen sets has been designed and fabricated for the heat transfer experiment of an LBE capsule of 11M-01K. In this paper, a series of thermal analyses and heat transfer experiments for a newly designed LBE capsule was implemented to study the effect of an increase in the value of heat input and its influence on temperature distribution in the capsule mock-up

  9. Effects of Specimen Diameters on the Distribution of Corrosion Fatigue Cracks

    OpenAIRE

    石原, 外美; 塩澤, 和章; 宮尾, 嘉寿

    1988-01-01

    The distribution of corrosion fatigue cracks observed on the un-notched round specimen surface differs with specimen diameter, especially in the low stress amplitude region. At a constant fatigue life ratio, many long cracks are initiated on the larger specimen, 12 mm (diameter), in comparison with the smaller specimen, 6 mm (diameter). On the other hand, in the high stress amplitude region of corrosion fatigue and fatigue in laboratory air, the distribution of cracks during the fatigue proce...

  10. Influence of specimen thickness on the fatigue behavior of notched steel plates subjected to laser shock peening

    Science.gov (United States)

    Granados-Alejo, V.; Rubio-González, C.; Vázquez-Jiménez, C. A.; Banderas, J. A.; Gómez-Rosas, G.

    2018-05-01

    The influence of specimen thickness on the fatigue crack initiation of 2205 duplex stainless steel notched specimens subjected to laser shock peening (LSP) was investigated. The purpose was to examine the effectiveness of LSP on flat components with different thicknesses. For the LSP treatment a Nd:YAG pulsed laser operating at 10 Hz with 1064 nm of wavelength was used; pulse density was 2500 pulses/cm2. The LSP setup was the waterjet arrangement without sample coating. Residual stress distribution as a function of depth was determined by the hole drilling method. Notched specimens 2, 3 and 4 mm thick were LSP treated on both faces and then fatigue loading was applied with R = 0.1. Experimental fatigue lives were compared with life predictions from finite element simulation. A good comparison of the predicted and experimental fatigue lives was observed. LSP finite element simulation helps in explaining the influence of thickness on fatigue lives in terms of equivalent plastic strain distribution variations associated with the change in thickness. It is demonstrated that specimen size effect is an important issue in applying LSP on real components. Reducing the specimen thickness, the fatigue life improvement induced by LSP is significantly increased. Fatigue life extension up to 300% is observed on thin specimens with LSP.

  11. Preliminary investigation of candidate specimens for the Egyptian environmental specimen bank

    International Nuclear Information System (INIS)

    Shawky, S.; Amer, H.; Schladot, J.D.; Ostapczuk, P.; Emons, H.; Abou El-Nour, F.

    2000-01-01

    In the frame of establishing an environmental monitoring program related to environmental specimen banking in egypt, some candidate specimens from the aquatic environment (Fish muscle, fish liver; mussels) were investigated. The selection of specimens and sampling sites is described. Specimens are chemically characterised with respect to some major and trace elements and the results are compared with data obtained from comparable specimens collected in aquatic ecosystems of germany

  12. Effect of dispersed phase particle size on microstructure of cup fracture

    International Nuclear Information System (INIS)

    Goritskij, V.M.; Guseva, I.A.

    1978-01-01

    A correlation-regressive analysis has been carried out to reveal the influence of the size and the mean distance between the disperse particles of deposits V(C,N) on the microstructure (size of micropores and cups, density of the cups) of a viscous cup-like fracture of specimens made of 30Kh2NMFA grade steel that has been hardened and annealed. It is shown that micropores develop at relatively large particles of deposits V(C,N) (>=0.04/m). A strong correlation linear connection exists between the size of a disperse particle of deposits V(C,N), the size of micropore and cup. This connection is attributable to the close, pairwise correlative connection between the size of the particle and the micropore, the micropore and the cup

  13. Pseudolipomatosis in Endometrial Specimens Does Not Represent Uterine Perforation.

    Science.gov (United States)

    Heller, Alexis

    2017-02-01

    Specimens of endometrial biopsies can sometimes present with an artifact within blood, composed of optically clear vacuoles mimicking adipose tissue, pseudolipomatosis. This artifact can be mistaken for adipose tissue and lead to an overdiagnosis of uterine perforation. We describe the case of pseudolipomatosis seen within the evacuated products of conception from a missed abortion. Areas of vacuolization in the blood clot mimicked adipose tissue. However, the vacuoles varied in size and did not contain adipocytes. Familiarity with this artifact will lead to avoidance of overdiagnosis of adipose tissue and uterine perforation in curettage specimens.

  14. Effects of antibiotics on protected specimen brush sampling in ventilator-associated pneumonia.

    Science.gov (United States)

    Prats, E; Dorca, J; Pujol, M; Garcia, L; Barreiro, B; Verdaguer, R; Gudiol, F; Manresa, F

    2002-05-01

    The effects of antibiotic treatment on the results of protected specimen brushing (PSB) in ventilator-associated pneumonia were prospectively assessed by performing this procedure before antibiotic treatment, and 12, 24, 48 and 72 h after initiation of antibiotic treatment, in 35 ventilated patients who developed pneumonia during mechanical ventilation. The number of micro-organisms isolated, their concentration (colony-forming units (cfu) mL(-1)), and the number of cases with a positive PSB (> or =10(3) cfu x mL(-1)) were evaluated. Within 12 h of the initiation of effective antibiotic treatment a rapid, significant decrease in the numbers of organisms isolated, their individual concentrations and the percentage of positive PSB results were observed. Certain bacterial species (Streptococcus pneumoniae, Haemophilus influenzee) appeared to be more vulnerable to antibiotics than others (Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumanni). This data confirms that prior antibiotic treatment, even after only a few hours of activity, significantly decreases the sensitivity of protected brush specimen; this effect appears to be particularly marked among the species involved in early ventilator associated pneumonia.

  15. How to open the treasure chest? Optimising DNA extraction from herbarium specimens.

    Science.gov (United States)

    Särkinen, Tiina; Staats, Martijn; Richardson, James E; Cowan, Robyn S; Bakker, Freek T

    2012-01-01

    Herbarium collections are potentially an enormous resource for DNA studies, but the use of herbarium specimens in molecular studies has thus far been slowed down by difficulty in obtaining amplifiable DNA. Here we compare a set of commercially available DNA extraction protocols and their performance in terms of DNA purity and yield, and PCR amplification success as measured by using three differentially sized markers, the rbcL barcoding marker (cpDNA), the LEAFY exon 3 (nrDNA), and the trnL((UAA)) P6 loop (cpDNA). Results reveal large differences between extraction methods, where DNA purity rather than yield is shown to be strongly correlated with PCR success. Amplicon size shows similarly strong correlation with PCR success, with the shortest fragment showing the highest success rate (78%, P6 loop, 10-143 base pairs (bp)) and the largest fragment the lowest success (10%, rbcL, 670 bp). The effect of specimen preparation method on PCR success was also tested. Results show that drying method strongly affects PCR success, especially the availability of fragments longer than 250 bp, where longer fragments are more available for PCR amplification in air dried material compared to alcohol dried specimens. Results from our study indicate that projects relying on poor-quality starting material such as herbarium or scat samples should focus on extracting pure DNA and aim to amplify short target regions (herbarium samples available into barcoding initiatives and other molecular studies.

  16. Small specimen test technology of fracture toughness in structural material F82H steel for fusion nuclear reactors

    International Nuclear Information System (INIS)

    Wakai, Eiichi; Ohtsuka, Hideo; Jitsukawa, Shiro; Matsukawa, Shingo; Ando, Masami

    2006-03-01

    Small specimen test technology (SSTT) has been developed to investigate mechanical properties of nuclear materials. SSTT has been driven by limited availability of effective irradiation volumes in test reactors and accelerator-based neutron and charged particle sources, and it is very useful for the reduction of waste materials produced in nuclear engineering. In this study new bend test machines have been developed to obtain fracture behaviors of F82H steel for very small bend specimens of pre-cracked t/2-1/3CVN (Charpy V-notch) with 20 mm-length and DFMB (deformation and fracture mini bend specimen) with 9 mm-length and disk compact tension of 0.18DCT type, and fracture behaviors were examined to evaluate DBTT (ductile-brittle transition temperature) at temperature from -180 to 25degC. The effect of specimen size on DBTT of F82H steel was also examined by using Charpy type specimens such as 1/2t-CVN, 1/3CVN and t/2-1/3CVN. In this paper, it also provides the information of the specimens irradiated at 250degC and 350degC to about 2 dpa in the capsule of 04M-67A and 04M-68A of JMTR experiments. (author)

  17. An Experimental Study of the Fracture Coalescence Behaviour of Brittle Sandstone Specimens Containing Three Fissures

    Science.gov (United States)

    Yang, S. Q.; Yang, D. S.; Jing, H. W.; Li, Y. H.; Wang, S. Y.

    2012-07-01

    To analyse the fracture coalescence behaviour of rock, rectangular prismatic sandstone specimens (80 × 160 × 30 mm in size) containing three fissures were tested under uniaxial compression. The strength and deformation behaviours of the specimens are first analysed by investigating the effects of the ligament angle β2 on the peak strength, peak strain and crack initiation stress of the specimens. To confirm the sequence of crack coalescence, a photographic monitoring technique is used throughout the entire period of deformation. Based on the results, the relationship between the real-time crack coalescence process and the axial stress-strain curve of brittle sandstone specimens is also developed, and this relationship can be used to evaluate the macroscopic deformation characteristics of pre-cracked rock. The equivalent strain evolution fields of the specimen, with α = β1 = 45° and β2 = 90°, are obtained using the digital image correlation technique and show good agreement with the experimental results of pre-cracked brittle sandstone. These experimental results are expected to improve the understanding of fracture mechanisms and be used in rock engineering with intermittent structures, such as deep underground excavated tunnels.

  18. Effect of NaCl Solution Spraying on Fatigue Lives of Smooth and Slit Specimens of 0.37% Carbon Steel

    Science.gov (United States)

    Makabe, Chobin; Ferdous, Md. Shafiul; Shimabukuro, Akimichi; Murdani, Anggit

    2017-07-01

    The fatigue crack initiation life and growth rate are affected by experimental conditions. A corrosive environment can be created in a laboratory by means of dropping salt water onto the specimen surface, spraying chloride mist into the experimental chamber, etc. In the case of smooth specimens of some metals, fatigue life is shortened and the fatigue limit disappears under such corrosive experimental conditions. In this study, the effects of intermittent spraying of 3% NaCl solution-mist on corrosion fatigue behavior were investigated. The material used was 0.37% carbon steel. This is called JIS S35C in Japan. Spraying of 3% NaCl solution-mist attacked the surface layer of the specimen. It is well known that the pitting, oxidation-reduction reaction, etc. affect the fatigue strength of metals in a corrosive environment. We carried out corrosion fatigue tests with smooth specimens, holed specimens and slit specimens. Then the effects of such specimen geometry on the fatigue strength were investigated when the NaCl solution-mist was sprayed onto the specimen surface. In the case of lower stress amplitude application in slit specimens, the fatigue life in a corrosive atmosphere was longer than that in the open air. It is discussed that the behavior is related to the crack closure which happens when the oxide builds up and clogs the crack or slit.

  19. An engineering method for estimating notch-size effect in fatigue tests on steel

    Science.gov (United States)

    Kuhn, Paul; Hardrath, Herbert F

    1952-01-01

    Neuber's proposed method of calculating a practical factor of stress concentration for parts containing notches of arbitrary size depends on the knowledge of a "new material constant" which can be established only indirectly. In this paper, the new constant has been evaluated for a large variety of steels from fatigue tests reported in the literature, attention being confined to stresses near the endurance limit. Reasonably satisfactory results were obtained with the assumption that the constant depends only on the tensile strength of the steel. Even in cases where the notches were cracks of which only the depth was known, reasonably satisfactory agreement was found between calculated and experimental factors. It is also shown that the material constant can be used in an empirical formula to estimate the size effect on unnotched specimens tested in bending fatigue.

  20. Impurity composition effect on work function in cylindrical specimens of niobium and low zirconium niobium base alloys

    International Nuclear Information System (INIS)

    Kobyakov, V.P.

    2000-01-01

    A study is made into poly- and single crystal cylindrical niobium specimens, prepared by various methods as well as into polycrystalline specimens of niobium base alloys doped with 1.2 and 1.6 % Zr. Thermionic work function is measured using a full current method. Several techniques are applied to determine the content of substitutional and interstitial impurities in specimens. The phase composition of polished section surface is also investigated. A work function increase is observed when a considerable amount of carbide phases occurs at the surface. This increase is comparable with the effect of going from a polycrystalline niobium specimen to a single crystal with (110) surface orientation [ru

  1. Representative volume element size of a polycrystalline aggregate with embedded short crack

    International Nuclear Information System (INIS)

    Simonovski, I.; Cizelj, L.

    2007-01-01

    A random polycrystalline aggregate model is proposed for evaluation of a representative volume element size (RVE) of a 316L stainless steel with embedded surface crack. RVE size is important since it defines the size of specimen where the influence of local microstructural features averages out, resulting in the same macroscopic response for geometrically similar specimen. On the other hand macroscopic responses of specimen with size smaller than RVE will, due to the microstructural features, differ significantly. Different sizes and orientations of grains, inclusions, voids,... etc are examples of such microstructural features. If a specimen size is above RVE size, classical continuum mechanics can be applied. On the other hand, advanced material models should be used for specimen with size below RVE. This paper proposes one such model, where random size, shape and orientation of grains are explicitly modeled. Crystal plasticity constitutive model is used to account for slip in the grains. RVE size is estimated by calculating the crack tip opening displacements of aggregates with different grain numbers. Progressively larger number of grains are included in the aggregates until the crack tip displacements for two consecutive aggregates of increasing size differ less than 1 %. At this point the model has reached RVE size. (author)

  2. Testing machine for fatigue crack kinetic investigation in specimens under bending

    International Nuclear Information System (INIS)

    Panasyuk, V.V.; Ratych, L.V.; Dmytrakh, I.N.

    1978-01-01

    A kinematic diagram of testing mashine for the investigation of fatigue crack kinetics in prismatic specimens, subjected to pure bending is described. Suggested is a technique of choosing an optimum ratio of the parameters of ''the testing machine-specimen'' system, which provide the stabilization of the stress intensity coefficient for a certain region of crack development under hard loading. On the example of the 40KhS and 15Kh2MFA steel specimens the pliability of the machine constructed according to the described diagram and designed for the 30ONxm maximum bending moment. The results obtained can be used in designing of the testing machines for studying pure bending under hard loading and in choosing the sizes of specimens with rectangular cross sections for investigations into the kinetics of the fatigue crack

  3. Effects of Crumb Rubber Size and Concentration on Performance of Porous Asphalt Mixtures

    Directory of Open Access Journals (Sweden)

    Altan Cetin

    2013-01-01

    Full Text Available The purpose of this study is to investigate the effect of size distribution and concentration of crumb rubber on the performance characteristics of porous asphalt mixture. The recycling of scrap tires in asphalt pavements appears as an important alternative providing a large-scale market. The characteristics of bitumen are very important with regard to service life of porous asphalt pavement. The experimental study consists of two main steps. Firstly, the mixture design was performed to determine the optimum bitumen content. In the latter step, the mixtures were modified by dry process using crumb rubber in three different grain size distributions of #4~#20, #20~#200, and #4~#200 and rubber content of 10%, 15%, and 20% as weight of optimum bitumen. The permeability, Cantabro abrasion loss, indirect tensile strength, moisture susceptibility, and resilient modulus tests were carried out on the specimens. Test results show that #20~#200 sized rubber particles reduced air voids and coefficient of permeability, while they increased the Cantabro abrasion loss. In general, increasing the crumb rubber size and content decreased the performance characteristics of the porous asphalt mixtures.

  4. Development of Reconstitution Technology for Surveillance Specimens

    International Nuclear Information System (INIS)

    Yasushi Atago; Shunichi Hatano; Eiichiro Otsuka

    2002-01-01

    The Japan Power Engineering and Inspection Corporation (JAPEIC) has been carrying out the project titled 'Nuclear Power Plant Integrated Management Technology (PLIM)' consigned by Japanese Ministry of Economy, Trade and Industry (METI) since 1996FY as a 10-years project. As one of the project themes, development of reconstitution technology for reactor pressure vessel (RPV/RV) surveillance specimens, which are installed in RPVs to monitor the neutron irradiation embrittlement on RPV/RV materials, is now on being carried out to deal with the long-term operation of nuclear power plants. The target of this theme is to establish the technical standard for applicability of reconstituted surveillance specimens including the reconstitution of the Charpy specimens and Compact Tension (CT) specimens. With the Charpy specimen reconstitution, application of 10 mm length inserts is used, which enables the conversion of tests from the LT-direction to the TL-direction. This paper presents the basic data from Charpy and CT specimens of RPV materials using the surveillance specimens obtained for un-irradiated materials including the following. 1) Reconstitution Technology of Charpy Specimens. a) The interaction between plastic zone and Heat Affected Zone (HAZ). b) The effects of the possible deviations from the standard specimens for the reconstituted specimens. 2) Reconstitution Technology of CT specimens. a) The correlation between fracture toughness and plastic zone width. Because the project is now in progress, this paper describes the outline of the results obtained as of the end of 2000 FY. (authors)

  5. Experimental investigation of the thickness effect for large as-welded SAW S355 steel specimens

    DEFF Research Database (Denmark)

    Ólafsson, Ólafur Magnús; Jensen, Jørgen Juncher; Berggreen, Christian

    2016-01-01

    The presented work aims to investigate and establish a pre-cise, thorough and detailed database from series of experi-mental testing of submerged arc welded (SAW) specimens of various thicknesses typically applied in ships and offshore structures and foundations. Welded structures of all sizes...... and shapes exhibit fatigue failure primarily in the welded region, rather than in the base material, due to imperfections and flaws relating to the welding procedure. The welded region has therefore received much attention from universities, re-search institutions along with industry as it is of significant...

  6. Effect of loading condition, specimen geometry, size-effect and ...

    Indian Academy of Sciences (India)

    Department of Civil Engineering, Institute of Technology, Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur 495009, India; Department of Civil Engineering, National Institute of Technology, Jamshedpur 831014, India; Department of Civil Engineering, Indian Institute of Technology, Kharagpur 721 302, India ...

  7. Fabrication of uranium carbide/beryllium carbide/graphite experimental-fuel-element specimens

    International Nuclear Information System (INIS)

    Muenzer, W.A.

    1978-01-01

    A method has been developed for fabricating uranium carbide/beryllium carbide/graphite fuel-element specimens for reactor-core-meltdown studies. The method involves milling and blending the raw materials and densifying the resulting blend by conventional graphite-die hot-pressing techniques. It can be used to fabricate specimens with good physical integrity and material dispersion, with densities of greater than 90% of the theoretical density, and with a uranium carbide particle size of less than 10 μm

  8. The pack size effect: Influence on consumer perceptions of portion sizes

    NARCIS (Netherlands)

    Hieke, Sophie; Palascha, Aikaterini; Jola, Corinne; Wills, Josephine; Raats, Monique M.

    2016-01-01

    Larger portions as well as larger packs can lead to larger prospective consumption estimates, larger servings and increased consumption, described as 'portion-size effects' and 'pack size effects'. Although related, the effects of pack sizes on portion estimates have received less attention. While

  9. Response of a PGNAA setup for pozzolan-based cement concrete specimens

    International Nuclear Information System (INIS)

    Naqvi, A.A.; Garwan, M.A.; Maslehuddin, M.; Nagadi, M.M.; Al-Amoudi, O.S.B.; Raashid, M.

    2010-01-01

    Pozzolanic materials are added to Portland cement concrete to increase its durability, particularly corrosion-resistance. In this study the elemental composition of a pozzolanic cement concrete was measured non-destructively utilizing an accelerator-based Prompt Gamma Ray Neutron Activation Analysis (PGNAA) setup. The optimum size of the pozzolanic cement concrete specimen was obtained through Monte Carlo simulations. The simulation results were experimentally verified through the γ-ray yield measurement from the pozzolanic cement concrete specimens as a function of their radii. The concentration of the pozzolanic material in the cement concrete specimens was evaluated by measuring γ-ray yield for calcium and iron from pozzolanic cement concrete specimens containing 5-80 wt% pozzolan. A good agreement was noted between the experimental values and the Monte Carlo simulation results, indicating an excellent response of the KFUPM accelerator-based PGNAA setup for pozzolan based concrete.

  10. Response of a PGNAA setup for pozzolan-based cement concrete specimens

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)], E-mail: aanaqvi@kfupm.edu.sa; Garwan, M.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Maslehuddin, M. [Center for Engineering Research, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Nagadi, M.M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Raashid, M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2010-04-15

    Pozzolanic materials are added to Portland cement concrete to increase its durability, particularly corrosion-resistance. In this study the elemental composition of a pozzolanic cement concrete was measured non-destructively utilizing an accelerator-based Prompt Gamma Ray Neutron Activation Analysis (PGNAA) setup. The optimum size of the pozzolanic cement concrete specimen was obtained through Monte Carlo simulations. The simulation results were experimentally verified through the {gamma}-ray yield measurement from the pozzolanic cement concrete specimens as a function of their radii. The concentration of the pozzolanic material in the cement concrete specimens was evaluated by measuring {gamma}-ray yield for calcium and iron from pozzolanic cement concrete specimens containing 5-80 wt% pozzolan. A good agreement was noted between the experimental values and the Monte Carlo simulation results, indicating an excellent response of the KFUPM accelerator-based PGNAA setup for pozzolan based concrete.

  11. Increasing the efficiency of digitization workflows for herbarium specimens.

    Science.gov (United States)

    Tulig, Melissa; Tarnowsky, Nicole; Bevans, Michael; Anthony Kirchgessner; Thiers, Barbara M

    2012-01-01

    The New York Botanical Garden Herbarium has been databasing and imaging its estimated 7.3 million plant specimens for the past 17 years. Due to the size of the collection, we have been selectively digitizing fundable subsets of specimens, making successive passes through the herbarium with each new grant. With this strategy, the average rate for databasing complete records has been 10 specimens per hour. With 1.3 million specimens databased, this effort has taken about 130,000 hours of staff time. At this rate, to complete the herbarium and digitize the remaining 6 million specimens, another 600,000 hours would be needed. Given the current biodiversity and economic crises, there is neither the time nor money to complete the collection at this rate.Through a combination of grants over the last few years, The New York Botanical Garden has been testing new protocols and tactics for increasing the rate of digitization through combinations of data collaboration, field book digitization, partial data entry and imaging, and optical character recognition (OCR) of specimen images. With the launch of the National Science Foundation's new Advancing Digitization of Biological Collections program, we hope to move forward with larger, more efficient digitization projects, capturing data from larger portions of the herbarium at a fraction of the cost and time.

  12. Effect of Particle Size on Mechanical Properties of Sawdust-High Density Polyethylene Composites under Various Strain Rates

    Directory of Open Access Journals (Sweden)

    Haliza Jaya

    2016-06-01

    Full Text Available There is a need to understand the effect of wood particle size, as it affects the characteristics of wood-based composites. This study considers the effect of wood particle size relative to the dynamic behavior of wood composites. The compression Split Hopkinson Pressure Bar (SHPB was introduced to execute dynamic compression testing at the strain rate of 650 s-1, 900 s-1, and 1100 s-1, whereas a conventional universal testing machine (UTM was used to perform static compression testing at the strain rate of 0.1 s-1, 0.01 s-1, and 0.001 s-1 for four different particle sizes (63 µm, 125 µm, 250 µm, and 500 µm. The results showed that mechanical properties of composites were positively affected by the particle sizes, where the smallest particle size gave the highest values compared to the others. Moreover, the particle size also affected the rate sensitivity and the thermal activation volume of sawdust/HDPE, where smaller particles resulted in lower rate sensitivity. For the post-damage analysis, the applied strain rates influenced deformation behavior differently for all particle sizes of the specimens. In a fractographic analysis under dynamic loading, the composites with large particles experienced severe catastrophic deformation and damages compared to the smaller particles.

  13. Effect of CT Specimen Thickness on the Mechanical Characteristics at the Crack Tip of Stress Corrosion Cracking in Ni-based Alloys

    Science.gov (United States)

    Yinghao, Cui; He, Xue; Lingyan, Zhao

    2017-12-01

    It’s important to obtain accurate stress corrosion crack(SCC) growth rate for quantitative life prediction of components in nuclear power plants. However, the engineering practice shows that the crack tip constraint effect has a great influence on the mechanical properties and crack growth rate of SCC at crack tip. To study the influence of the specimen thickness on the crack tip mechanical properties of SCC, the stress, strain and C integral at creep crack tip are analyzed under different specimens thickness. Results show that the cracked specimen is less likely to crack due to effect of crack tip constraint. When the thickness ratio B/W is larger than 0.1, the crack tip constraint is almost ineffective. Value of C integral is the largest when B/W is 0.25. Then specimen thickness has little effect on the value of C integral. The effect of specimen thickness on the value of C integral is less significant at higher thickness ratio.

  14. Size effect in radiation damage

    International Nuclear Information System (INIS)

    Brumovsky, M.

    1979-01-01

    Radiation embrittlement of nuclear reactor pressure vessel steels is mostly measured using small standard specimens in dynamic bend tests. Their dimensions are much smaller than those of the reactor. The increase in the critical temperature (transition temperature from the brittle-to-ductile fracture) is normally measured using standard Charpy-V type specimens or small CT-type specimens. This increase is then used as the main parameter for the pressure vessel safety evaluation. The philosophy of experiments is discussed used for the nonirradiated and irradiated pressure vessel steels. A comparison of the increase in the transition temperature measured in different types of specimens using various testing methods (static and dynamic bend tests with notch or crack) is also made. The results of this comparison and another study showed a relatively good agreement. (author)

  15. Some recent innovations in small specimen testing

    International Nuclear Information System (INIS)

    Odette, G.R.; He, M.; Gragg, D.; Klingensmith, D.; Lucas, G.E.

    2002-01-01

    New innovative small specimen test techniques are described. Finite element simulations show that combinations of cone indentation pile-up geometry and load-penetration depth relations can be used to determine both the yield stress and strain-hardening behavior of a material. Techniques for pre-cracking and testing sub-miniaturized fracture toughness bend bars, with dimensions of 1.65x1.65x9 mm 3 , or less, are described. The corresponding toughness-temperature curves have a very steep transition slope, primarily due to rapid loss of constraint, which has advantages in some experiments to characterize the effects of specified irradiation variables. As one example of using composite specimens, an approach to evaluating helium effects is proposed, involving diffusion bonding small wires of a 54 Fe-based ferritic-martensitic alloy to a surrounding fracture specimen composed of an elemental Fe-based alloy. Finally, we briefly outline some potential approaches to multipurpose specimens and test automation

  16. Single specimen fracture toughness determination procedure using instrumented impact test

    International Nuclear Information System (INIS)

    Rintamaa, R.

    1993-04-01

    In the study a new single specimen test method and testing facility for evaluating dynamic fracture toughness has been developed. The method is based on the application of a new pendulum type instrumented impact tester equipped with and optical crack mouth opening displacement (COD) extensometer. The fracture toughness measurement technique uses the Double Displacement Ratio (DDR) method, which is based on the assumption that the specimen is deformed as two rigid arms that rotate around an apparent centre of rotation. This apparent moves as the crack grows, and the ratio of COD versus specimen displacement changes. As a consequence the onset ductile crack initiation can be detected on the load-displacement curve. Thus, an energy-based fracture toughness can be calculated. In addition the testing apparatus can use specimens with the Double ligament size as compared with the standard Charpy specimen which makes the impact testing more appropriate from the fracture mechanics point of view. The novel features of the testing facility and the feasibility of the new DDR method has been verified by performing an extensive experimental and analytical study. (99 refs., 91 figs., 27 tabs.)

  17. A cylindrical specimen holder for electron cryo-tomography

    International Nuclear Information System (INIS)

    Palmer, Colin M.; Löwe, Jan

    2014-01-01

    The use of slab-like flat specimens for electron cryo-tomography restricts the range of viewing angles that can be used. This leads to the “missing wedge” problem, which causes artefacts and anisotropic resolution in reconstructed tomograms. Cylindrical specimens provide a way to eliminate the problem, since they allow imaging from a full range of viewing angles around the tilt axis. Such specimens have been used before for tomography of radiation-insensitive samples at room temperature, but never for frozen-hydrated specimens. Here, we demonstrate the use of thin-walled carbon tubes as specimen holders, allowing the preparation of cylindrical frozen-hydrated samples of ribosomes, liposomes and whole bacterial cells. Images acquired from these cylinders have equal quality at all viewing angles, and the accessible tilt range is restricted only by the physical limits of the microscope. Tomographic reconstructions of these specimens demonstrate that the effects of the missing wedge are substantially reduced, and could be completely eliminated if a full tilt range was used. The overall quality of these tomograms is still lower than that obtained by existing methods, but improvements are likely in future. - Highlights: • The missing wedge is a serious problem for electron cryo-tomography. • Cylindrical specimens allow the missing wedge to be eliminated. • Carbon nanopipettes can be used as cylindrical holders for tomography of frozen-hydrated specimens. • Cryo-tomography of cylindrical biological samples demonstrates a reduction of deleterious effects associated with the missing wedge

  18. Rehydration of forensically important larval Diptera specimens.

    Science.gov (United States)

    Sanford, Michelle R; Pechal, Jennifer L; Tomberlin, Jeffery K

    2011-01-01

    Established procedures for collecting and preserving evidence are essential for all forensic disciplines to be accepted in court and by the forensic community at large. Entomological evidence, such as Diptera larvae, are primarily preserved in ethanol, which can evaporate over time, resulting in the dehydration of specimens. In this study, methods used for rehydrating specimens were compared. The changes in larval specimens with respect to larval length and weight for three forensically important blow fly (Diptera: Calliphoridae) species in North America were quantified. Phormia regina (Meigen), Cochliomyia macellaria (F.), and Chrysomya rufifacies (Macquart) third-instar larvae were collected from various decomposing animals and preserved with three preservation methods (80% ethanol, 70% isopropyl alcohol, and hot-water kill then 80% ethanol). Preservative solutions were allowed to evaporate. Rehydration was attempted with either of the following: 80% ethanol, commercial trisodium phosphate substitute solution, or 0.5% trisodium phosphate solution. All three methods partially restored weight and length of specimens recorded before preservation. Analysis of variance results indicated that effects of preservation, rehydration treatment, and collection animal were different in each species. The interaction between preservative method and rehydration treatment had a significant effect on both P. regina and C. macellaria larval length and weight. In addition, there was a significant interaction effect of collection animal on larval C. macellaria measurements. No significant effect was observed in C. rufifacies larval length or weight among the preservatives or treatments. These methods could be used to establish a standard operating procedure for dealing with dehydrated larval specimens in forensic investigations.

  19. Clinical evaluation of a mobile digital specimen radiography system for intraoperative specimen verification.

    Science.gov (United States)

    Wang, Yingbing; Ebuoma, Lilian; Saksena, Mansi; Liu, Bob; Specht, Michelle; Rafferty, Elizabeth

    2014-08-01

    Use of mobile digital specimen radiography systems expedites intraoperative verification of excised breast specimens. The purpose of this study was to evaluate the performance of a such a system for verifying targets. A retrospective review included 100 consecutive pairs of breast specimen radiographs. Specimens were imaged in the operating room with a mobile digital specimen radiography system and then with a conventional digital mammography system in the radiology department. Two expert reviewers independently scored each image for image quality on a 3-point scale and confidence in target visualization on a 5-point scale. A target was considered confidently verified only if both reviewers declared the target to be confidently detected. The 100 specimens contained a total of 174 targets, including 85 clips (49%), 53 calcifications (30%), 35 masses (20%), and one architectural distortion (1%). Although a significantly higher percentage of mobile digital specimen radiographs were considered poor quality by at least one reviewer (25%) compared with conventional digital mammograms (1%), 169 targets (97%), were confidently verified with mobile specimen radiography; 172 targets (98%) were verified with conventional digital mammography. Three faint masses were not confidently verified with mobile specimen radiography, and conventional digital mammography was needed for confirmation. One faint mass and one architectural distortion were not confidently verified with either method. Mobile digital specimen radiography allows high diagnostic confidence for verification of target excision in breast specimens across target types, despite lower image quality. Substituting this modality for conventional digital mammography can eliminate delays associated with specimen transport, potentially decreasing surgical duration and increasing operating room throughput.

  20. Innovations in macroscopic evaluation of pancreatic specimens and radiologic correlation

    Directory of Open Access Journals (Sweden)

    Charikleia Triantopoulou

    2016-01-01

    Full Text Available The purpose of this study was to evaluate the feasibility of a novel dissection technique of surgical specimens in different cases of pancreatic tumors and provide a radiologic pathologic correlation. In our hospital, that is a referral center for pancreatic diseases, the macroscopic evaluation of the pancreatectomy specimens is performed by the pathologists using the axial slicing technique (instead of the traditional procedure with longitudinal opening of the main pancreatic and/or common bile duct and slicing along the plane defined by both ducts. The specimen is sliced in an axial plane that is perpendicular to the longitudinal axis of the descending duodenum. The procedure results in a large number of thin slices (3–4 mm. This plane is identical to that of CT or MRI and correlation between pathology and imaging is straightforward. We studied 70 cases of suspected different solid and cystic pancreatic tumors and we correlated the tumor size and location, the structure—consistency (areas of necrosis—hemorrhage—fibrosis—inflammation, the degree of vessels’ infiltration, the size of pancreatic and common bile duct and the distance from resection margins. Missed findings by imaging or pitfalls were recorded and we tried to explain all discrepancies between radiology evaluation and the histopathological findings. Radiologic-pathologic correlation is extremely important, adding crucial information on imaging limitations and enabling quality assessment of surgical specimens. The deep knowledge of different pancreatic tumors’ consistency and way of extension helps to improve radiologists’ diagnostic accuracy and minimize the radiological-surgical mismatching, preventing patients from unnecessary surgery.

  1. Development of the plant life management technology for RPV steels [ - Current status of surveillance test specimen reconstitution program -

    International Nuclear Information System (INIS)

    Kazunobu, Sakamoto; Eliichiro, Otsuka; Yoshiaki, Oka; Kosei, Taguchi; Michiyoshi, Yamamoto

    2001-01-01

    In order to develop the reconstitution technology to standardize surveillance test specimen reconstitution practices to deal with the extended service life of reactor pressure vessels, the Japan Power Engineering and Inspection Corporation (JAPEIC) has been carried out the project entrusted by the Ministry of International Trade and Industry (MITI). We focus on a correlation between the reduction of absorbed energy and the interaction of the heat affected zone (HAZ) and the plastic zone, to establish applicable reconstitution conditions for Charpy specimens. The relationship between the plastic zone width and the absorbed energy has been obtained by estimating the plastic zone width from the hardness distribution of the Charpy specimens. Impact tests of reconstituted specimens with 10 mm-length insert using the surface activated joining method were performed and the test results were compared to those obtained by the standard specimens. By comparing the length of insert material to the sum of HAZ width and plastic zone width, it is clear that the interaction causes the reduction of the absorbed energy. Hence, the applicable conditions of reconstituted Charpy specimens could be assessed by comparing the insert length to the sum of HAZ width and plastic zone width. Moreover the effects of the possible deviations from the standard shape and size specimens for the reconstituted specimens were studied. (authors)

  2. Hit size effectiveness in relation to the microdosimetric site size

    International Nuclear Information System (INIS)

    Varma, M.N.; Wuu, C.S.; Zaider, M.

    1994-01-01

    This paper examines the effect of site size (that is, the diameter of the microdosimetric volume) on the hit size effectiveness function (HSEF), q(y), for several endpoints relevant in radiation protection. A Bayesian and maximum entropy approach is used to solve the integral equations that determine, given microdosimetric spectra and measured initial slopes, the function q(y). All microdosimetric spectra have been calculated de novo. The somewhat surprising conclusion of this analysis is that site size plays only a minor role in selecting the hit size effectiveness function q(y). It thus appears that practical means (e.g. conventional proportional counters) are already at hand to actually implement the HSEF as a radiation protection tool. (Author)

  3. Microwave tissue coagulation: effects of power and treatment time on coagulation size

    International Nuclear Information System (INIS)

    Kang, Seung Pyung; Kim, Young Hwan; Park, Dong Man; Kim, Jeong Seok; Park, Seo Young; Cha, Soon Joo; Hur, Gham

    1999-01-01

    To determine the effects of power and coagulation time on lesion size of ex-vivo bovine liver using microwaves. Six bovine livers were divided into two groups (first group : 30W output, second group : 60W output) and microwave coagulation was performed for 30, 60, and 120 sec. Thermal injury site was then observed by means of sonography, and the maximal transverse diameter of the echo-change portion after microwave coagulation was measured. On the section of specimen, maximal transverse diameters of the thermal injury site were measured by gross inspection and compared with the result of sonographic measurement. Maximal transverse diameters of hyperechoic lesions of the first group, as seen on sonography, were 8.3mm, 12.2mm, and 15.6mm, and the maximal transverse diameters of thermal injury sites on gross specimens were 9.1mm, 12.0mm, and 15.1mm, respectively. Maximal transverse diameters of hyperechoic lesions of the second group, as seen on sonography, were 12.1mm, 17.4mm, and 21.2mm and maximal transverse diameters of thermal injury sites on gross specimens were 13.2mm, 16.0mm, and 20.0mm, respectively. Statistically maximal transverse diameters of hyperechoic lesions, as seen on sonography, correlated closely with the gross findings of maximal transverse diameters of thermal injury sites (P < .05). Maximal transverse diameters of thermal injury sites were significantly increased as the output of the microwave coagulator and the duration of coagulation time increased (P < .05)

  4. Increasing the efficiency of digitization workflows for herbarium specimens

    Directory of Open Access Journals (Sweden)

    Melissa Tulig

    2012-07-01

    Full Text Available The New York Botanical Garden Herbarium has been databasing and imaging its estimated 7.3 million plant specimens for the past 17 years. Due to the size of the collection, we have been selectively digitizing fundable subsets of specimens, making successive passes through the herbarium with each new grant. With this strategy, the average rate for databasing complete records has been 10 specimens per hour. With 1.3 million specimens databased, this effort has taken about 130,000 hours of staff time. At this rate, to complete the herbarium and digitize the remaining 6 million specimens, another 600,000 hours would be needed. Given the current biodiversity and economic crises, there is neither the time nor money to complete the collection at this rate.Through a combination of grants over the last few years, The New York Botanical Garden has been testing new protocols and tactics for increasing the rate of digitization through combinations of data collaboration, field book digitization, partial data entry and imaging, and optical character recognition (OCR of specimen images. With the launch of the National Science Foundation’s new Advancing Digitization of Biological Collections program, we hope to move forward with larger, more efficient digitization projects, capturing data from larger portions of the herbarium at a fraction of the cost and time.

  5. Damage Study in Notched Particulate Composie Specimens Under Nonuniform Strain Loading

    National Research Council Canada - National Science Library

    Kwon, Y

    1999-01-01

    .... The numerical specimen considered had a semi-circular notch with a linearly varying length. The initial crack size occurring at the notch tip was modeled and predicted using a micro/macro-approach along with a damage model...

  6. Design and use of nonstandard tensile specimens for irradiated materials testing

    International Nuclear Information System (INIS)

    Panayotou, N.F.

    1984-10-01

    Miniature, nonstandard, tensile-type specimens have been developed for use in radiation effects experiments at high energy neutron sources where the useful radiation volume is as small as a few cubic centimeters. The end result of our development is a sheet-type specimen, 12.7 mm long with a 5.1 mm long, 1.0 mm wide gage section, which is typically fabricated from 0.25 mm thick sheet stock by a punching technique. Despite this miniature geometry, it has been determined that the data obtained using these miniature specimens are in good agreement with data obtained using much larger specimens. This finding indicates that miniature tensile specimen data may by used for engineering design purposes. Furthermore, it is clear that miniature tensile specimen technology is applicable to fields other than the study of radiation effects. This paper describes the miniature specimen technology which was developed and compares the data obtained from these miniature specimens to data obtained from much larger specimens. 9 figures

  7. Prediction of retained residual stresses in laboratory fracture mechanics specimens extracted from welded components

    International Nuclear Information System (INIS)

    Hurlston, R.G.; Sherry, A.H.; James, P.; Sharples, J.K.

    2015-01-01

    The measurement of weld material fracture toughness properties is important for the structural integrity assessment of engineering components. However, welds can contain high levels of residual stress and these can be retained in fracture mechanics specimens, particularly when machined from non-stress relieved welds. Retained residual stresses can make the measurement of valid fracture toughness properties difficult. This paper describes the results of analytical work undertaken to investigate factors that can influence the magnitude and distribution of residual stresses retained in fracture mechanics specimen blanks extracted from as-welded ferritic and austenitic stainless steel plates. The results indicate that significant levels of residual stress can be retained in specimen blanks prior to notching, and that the magnitude and distribution of stress is dependent upon material properties, specimen geometry and size, and extraction location through the thickness of the weld. Finite element modelling is shown to provide a useful approach for estimating the level and distributions of retained residual stresses. A new stress partitioning approach has been developed to estimate retained stress levels and results compare favourably with FE analysis and available experimental data. The approach can help guide the selection of specimen geometry and machining strategies to minimise the level of residual stresses retained in fracture mechanics specimen blanks extracted from non stress-relieved welds and thus improve the measurement of weld fracture toughness properties. - Highlights: • A simplified method for generating realistic weld residual stresses has been developed. • It has been shown that significant levels of residual stress can be retained within laboratory fracture mechanics specimens. • The level and distribution is dependant upon material, specimen type, specimen size and extraction location. • A method has been developed to allow estimates of the

  8. Elastic-plastic analysis of fracture mechanics test specimens. Part 2

    International Nuclear Information System (INIS)

    Talja, H.; Wallin, K.

    1984-12-01

    This is second part of the report of the research program 'Comparisons between computational and experimental elastic-plastic results' started at the Technical Research Centre of Finland in 1981. The first part of the research program was reported earlier and contained a two dimensional linear elastic finite element analysis of four specimen geometries (CT, RCT, ASTM-3P and Charpy-V) and testing and elastic-plastic analysis of the specimen (EGF71; 1TCT, material A 542). In this report the second part of the program containing the testing and 2-D elastic-plastic analyses of five specimens is described. The four specimen geometries mentioned above and two different materials (stainless steel AISI 304 and ferrite pressure vessel steel A533B) are considered. The following comparisons are presented in the report: load vs. load displacement curves, J-integral, crack opening displacement (COD), J vs. COD and the size of the plastic zone. The agreement between the computational and experimental results is quite good. Complete agreement can be achieved only with 3-dimensional calculation models. (author)

  9. The size effect in corrosion greatly influences the predicted life span of concrete infrastructures.

    Science.gov (United States)

    Angst, Ueli M; Elsener, Bernhard

    2017-08-01

    Forecasting the life of concrete infrastructures in corrosive environments presents a long-standing and socially relevant challenge in science and engineering. Chloride-induced corrosion of reinforcing steel in concrete is the main cause for premature degradation of concrete infrastructures worldwide. Since the middle of the past century, this challenge has been tackled by using a conceptual approach relying on a threshold chloride concentration for corrosion initiation ( C crit ). All state-of-the-art models for forecasting chloride-induced steel corrosion in concrete are based on this concept. We present an experiment that shows that C crit depends strongly on the exposed steel surface area. The smaller the tested specimen is, the higher and the more variable C crit becomes. This size effect in the ability of reinforced concrete to withstand corrosion can be explained by the local conditions at the steel-concrete interface, which exhibit pronounced spatial variability. The size effect has major implications for the future use of the common concept of C crit . It questions the applicability of laboratory results to engineering structures and the reproducibility of typically small-scale laboratory testing. Finally, we show that the weakest link theory is suitable to transform C crit from small to large dimensions, which lays the basis for taking the size effect into account in the science and engineering of forecasting the durability of infrastructures.

  10. Effects of Particle Size and Cement Replacement of LCD Glass Powder in Concrete

    Directory of Open Access Journals (Sweden)

    Seong Kyum Kim

    2017-01-01

    Full Text Available The high quality liquid crystal display (LCD processing waste glass (LPWG generated from the manufacturing process of Korea’s LCD industries, having the world’s highest technological level and production, was finely ground into particles smaller than cement particles (higher fineness than OPC to verify their applicability and performance as a replacement for cement. For a concrete mix having a W/B ratio of 0.44, cement was replaced with LPWG glass powder (LGP at ratios of 5, 10, 15, and 20% (LGP12 and 5 and 10% (LGP5 according to the particle size to prepare test cylinder specimens, which were tested with respect to air contents, slump in fresh concrete, and compressive strength and splitting tensile strength of hardened concrete. The microstructure of the concrete specimens was analyzed through Scanning Electron Microscopy (SEM, Energy Dispersive X-ray (EDX, and a Mercury Intrusion Porosimetry (MIP. Replacement of cement with LGP for cement could effectively decrease the quantity of cement used due to the excellent performance of LGP. It may positively contribute to the sustainable development of the cement industry as well as waste recycling and environment conservation on a national scale.

  11. Effect of heating rate and grain size on the melting behavior of the alloy Nb-47 mass % Ti in pulse-heating experiments

    International Nuclear Information System (INIS)

    Basak, D.; Boettinger, W.J.; Josell, D.; Coriell, S.R.; McClure, J.L.; Cezairliyan, A.

    1999-01-01

    The effect of heating rate and grain size on the melting behavior of Nb-47 mass% Ti is measured and modeled. The experimental method uses rapid resistive self-heating of wire specimens at rates between ∼10 2 and ∼10 4 K/s and simultaneous measurement of radiance temperature and normal spectral emissivity as functions of time until specimen collapse, typically between 0.4 and 0.9 fraction melted. During heating, a sharp drop in emissivity is observed at a temperature that is independent of heating rate and grain size. This drop is due to surface and grain boundary melting at the alloy solidus temperature even though there is very little deflection (limited melting) of the temperature-time curve from the imposed heating rate. Above the solidus temperature, the emissivity remains nearly constant with increasing temperature and the temperature vs time curve gradually reaches a sloped plateau over which the major fraction of the specimen melts. As the heating rate and/or grain size is increased, the onset temperature of the sloped plateau approaches the alloy liquidus temperature and the slope of the plateau approaches zero. This interpretation of the shapes of the temperature-time-curves is supported by a model that includes diffusion in the solid coupled with a heat balance during the melting process. There is no evidence of loss of local equilibrium at the melt front during melting in these experiments

  12. Atomic size and local order effects on the high temperature strength of binary Mg alloys

    Energy Technology Data Exchange (ETDEWEB)

    Abaspour, Saeideh, E-mail: s.abaspour78@gmail.com [ARC-Centre of Excellence for Design in Light Metals, Materials Engineering, School of Engineering, The University of Queensland, Brisbane QLD 4072 (Australia); Queensland Centre for Advanced Materials Processing and Manufacturing (AMPAM), The University of Queensland (Australia); Zambelli, Victor [ARC-Centre of Excellence for Design in Light Metals, Materials Engineering, School of Engineering, The University of Queensland, Brisbane QLD 4072 (Australia); Dargusch, Matthew [Queensland Centre for Advanced Materials Processing and Manufacturing (AMPAM), The University of Queensland (Australia); Cáceres, Carlos H. [ARC-Centre of Excellence for Design in Light Metals, Materials Engineering, School of Engineering, The University of Queensland, Brisbane QLD 4072 (Australia)

    2016-09-15

    The solid solution strengthening introduced by Ca (0.6 and 0.9 at%) and Sn 0.5–2.5 at%) was studied through tensile, compression and stress relaxation tests at room temperature, 373 K (100 °C) and 453 K (180 °C) on solution heat-treated and quenched specimens and compared with existing data for binary alloys containing Ca, Sn, Y, Gd, Nd, Zn and Al as well as for AZ91 alloy. At room temperature the solution-hardening rate introduced by Ca and Sn was much higher than that of Al, matching those of Y, Gd and Zn. Calcium also reduced the tension/compression asymmetry. At high temperature Ca effectively prevented stress relaxation, nearly matching Y, Gd and Nd. Tin was less effective, but still outperformed Al and AZ91 at low stresses. The effects at room and high temperature introduced by Ca and Sn appeared consistent with the presence of short-range order, in line with those introduced by Y, Nd, Gd and Zn. The larger than Mg atom size of Ca, Nd, Gd and Y can be expected to intensify the local order by strengthening the atomic bonds through its effects on the local electron density, accounting for their greater strengthening at high temperature. For given difference in atomic size, the effects on the local order are expected to be lesser for smaller sized atoms like Sn and Zn, hence their more subdued effects.

  13. Effect of ultraviolet light on creatinine measurement in jaundiced specimens

    International Nuclear Information System (INIS)

    Nisbet, J.A.; D'Souza, R.

    1986-01-01

    During initial evaluation of a creatinine method using the RA-1000 analyser, experiments with addition of bilirubin indicated negligible interference. However the finding of a 'zero' creatinine value in an extremely jaundiced specimen prompted to re-examine the method. In contrast to earlier findings with normal plasma containing added bilirubin, the authors found that plasma from moderately or severely jaundiced patients gave creatinine values lower than those obtained with a reference method. Since bilirubin has been implicated in the interference, the authors studied the effect of destroying bilirubin with ultraviolet light to see if this provided a practical solution to the problem. (Auth.)

  14. Effect of specimen geometry on the variability in fatigue crack growth rate

    International Nuclear Information System (INIS)

    Tsuji, Hirokazu; Nakajima, Hajime; Kondo, Tatsuo

    1982-02-01

    Fatigue crack growth tests on SA 533 grade B class 1 steel were conducted in air with both contoured double cantilever beam (CDCB) specimens and compact-tension (CT) specimens for comparison, which corresponded to the ΔK constant and ΔK increasing fatigue tests respectively. The variability of the measured values was examined statistically, and possible sources of the determined variability were discussed. The variability in the ΔK increasing fatigue tests with the CT specimens was found to be substantially greater than that in the ΔK constant fatigue tests with the CDCB specimens employed in the present study. In addition, the width of the scatter as well as in the degree of deviation from the expected linearity in da/dN versus ΔK plots were found to be varied depending on the level of ΔK in the CT specimen. Based on the results, a conclusion was drawn that constant ΔK type tests should be preferred in the tests where accuracy and reproducibility of crack growth rate measurement was of particular importance. (author)

  15. Effect Sizes in Gifted Education Research

    Science.gov (United States)

    Gentry, Marcia; Peters, Scott J.

    2009-01-01

    Recent calls for reporting and interpreting effect sizes have been numerous, with the 5th edition of the "Publication Manual of the American Psychological Association" (2001) calling for the inclusion of effect sizes to interpret quantitative findings. Many top journals have required that effect sizes accompany claims of statistical significance.…

  16. Rock sampling. [method for controlling particle size distribution

    Science.gov (United States)

    Blum, P. (Inventor)

    1971-01-01

    A method for sampling rock and other brittle materials and for controlling resultant particle sizes is described. The method involves cutting grooves in the rock surface to provide a grouping of parallel ridges and subsequently machining the ridges to provide a powder specimen. The machining step may comprise milling, drilling, lathe cutting or the like; but a planing step is advantageous. Control of the particle size distribution is effected primarily by changing the height and width of these ridges. This control exceeds that obtainable by conventional grinding.

  17. [Effect sizes, statistical power and sample sizes in "the Japanese Journal of Psychology"].

    Science.gov (United States)

    Suzukawa, Yumi; Toyoda, Hideki

    2012-04-01

    This study analyzed the statistical power of research studies published in the "Japanese Journal of Psychology" in 2008 and 2009. Sample effect sizes and sample statistical powers were calculated for each statistical test and analyzed with respect to the analytical methods and the fields of the studies. The results show that in the fields like perception, cognition or learning, the effect sizes were relatively large, although the sample sizes were small. At the same time, because of the small sample sizes, some meaningful effects could not be detected. In the other fields, because of the large sample sizes, meaningless effects could be detected. This implies that researchers who could not get large enough effect sizes would use larger samples to obtain significant results.

  18. Size effects in shear interfaces

    OpenAIRE

    GARNIER, J

    2001-01-01

    In physical modelling (centrifuge tests, calibration chambers, laboratory tests), the size of the soil particles may not be negligible when compared to the dimensions of the models. Size effects may so disturb the response of the models and the experimental data obtained on these cannot be extended to true scale conditions. Different tests have been performed to study and quantify the size effects that may happen in shear interfaces between soils and structures : modified shear box tests, pul...

  19. Effect of chip size on mechanical property and microstructure of AZ91D magnesium alloy prepared by solid state recycling

    International Nuclear Information System (INIS)

    Hu Maoliang; Ji Zesheng; Chen Xiaoyu; Zhang Zhenkao

    2008-01-01

    In this study, different kinds of AZ91D magnesium alloy chips were prepared by solid state recycling. Mechanical properties and microstructures of the recycled specimens were investigated. Various microstructural analyses were performed using the techniques of optical microscopy, scanning electron microscopy and oxygen-nitrogen analysis. Microstructural observations revealed that all the recycled specimens consisted of fine grains due to dynamic recrystallization. The oxide precipitate content is closely related to the recycled chip size. Accumulated oxygen concentration linearly increases with the total surface area of the machined chips in the recycled specimens. Ambient oxide in the recycled specimen contributes to a higher ultimate tensile strength and a higher elongation to failure; however, excessive oxide in the recycled specimen may adversely affect the elongation to failure

  20. 16 CFR Figure 3 to Part 1610 - Specimen Holder Supported in Specimen Rack

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Specimen Holder Supported in Specimen Rack 3 Figure 3 to Part 1610 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FLAMMABLE FABRICS ACT... Holder Supported in Specimen Rack ER25MR08.002 ...

  1. A Primer on Basic Effect Size Concepts.

    Science.gov (United States)

    Elmore, Patricia B.; Rotou, Ourania

    The increased interest in reporting effect sizes means that it is necessary to consider what should be included in a primer on effect sizes. A review of papers on effect sizes and commonly repeated statistical analyses suggests that it is important to discuss effect sizes relative to bivariate correlation, t-tests, analysis of variance/covariance,…

  2. Small specimen technique for assessing mechanical properties of metallic components

    Energy Technology Data Exchange (ETDEWEB)

    Lobo, Raquel M.; Andrade, Arnaldo H.P.; Morcelli, Aparecido E., E-mail: rmlobo@ipen.br, E-mail: morcelliae@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2017-11-01

    Small Punch Test (SPT) is one of the most promising techniques of small specimen test, which was originally applied in testing of irradiated materials in nuclear engineering. Then it was introduced to other fields as an almost nondestructive method to measure the local mechanical properties that are difficult to be obtained using conventional mechanical tests. Most studies to date are focused on metallic materials, although SPT applications are recently spreading to other materials. The small punch test (SPT) employs small-sized specimens (for example, samples measuring 8 mm in diameter and 0.5 mm thick). The specimen is firmly clamped between two circular dies and is bi-axially strained until failure into a circular hole using a hemispherical punch. The 'load-punch displacement' record can be used to estimate the yield strength, the ultimate tensile strength, the tensile elongation, and the temperature of the ductile-to-brittle transition. Recently, some researchers are working on the use of miniature notched or pre-cracked specimens (denoted as p-SPT) to validate its geometry and dimensions for obtaining the fracture properties of metallic materials. In a first approach, the technique makes it possible to convert primary experimental data into conventional mechanical properties of a massive specimen. In this paper a comprehensive review of the different STP applications is presented with the aim of clarifying its usefulness. (author)

  3. Small specimen technique for assessing mechanical properties of metallic components

    International Nuclear Information System (INIS)

    Lobo, Raquel M.; Andrade, Arnaldo H.P.; Morcelli, Aparecido E.

    2017-01-01

    Small Punch Test (SPT) is one of the most promising techniques of small specimen test, which was originally applied in testing of irradiated materials in nuclear engineering. Then it was introduced to other fields as an almost nondestructive method to measure the local mechanical properties that are difficult to be obtained using conventional mechanical tests. Most studies to date are focused on metallic materials, although SPT applications are recently spreading to other materials. The small punch test (SPT) employs small-sized specimens (for example, samples measuring 8 mm in diameter and 0.5 mm thick). The specimen is firmly clamped between two circular dies and is bi-axially strained until failure into a circular hole using a hemispherical punch. The 'load-punch displacement' record can be used to estimate the yield strength, the ultimate tensile strength, the tensile elongation, and the temperature of the ductile-to-brittle transition. Recently, some researchers are working on the use of miniature notched or pre-cracked specimens (denoted as p-SPT) to validate its geometry and dimensions for obtaining the fracture properties of metallic materials. In a first approach, the technique makes it possible to convert primary experimental data into conventional mechanical properties of a massive specimen. In this paper a comprehensive review of the different STP applications is presented with the aim of clarifying its usefulness. (author)

  4. Sequencing historical specimens: successful preparation of small specimens with low amounts of degraded DNA.

    Science.gov (United States)

    Sproul, John S; Maddison, David R

    2017-11-01

    Despite advances that allow DNA sequencing of old museum specimens, sequencing small-bodied, historical specimens can be challenging and unreliable as many contain only small amounts of fragmented DNA. Dependable methods to sequence such specimens are especially critical if the specimens are unique. We attempt to sequence small-bodied (3-6 mm) historical specimens (including nomenclatural types) of beetles that have been housed, dried, in museums for 58-159 years, and for which few or no suitable replacement specimens exist. To better understand ideal approaches of sample preparation and produce preparation guidelines, we compared different library preparation protocols using low amounts of input DNA (1-10 ng). We also explored low-cost optimizations designed to improve library preparation efficiency and sequencing success of historical specimens with minimal DNA, such as enzymatic repair of DNA. We report successful sample preparation and sequencing for all historical specimens despite our low-input DNA approach. We provide a list of guidelines related to DNA repair, bead handling, reducing adapter dimers and library amplification. We present these guidelines to facilitate more economical use of valuable DNA and enable more consistent results in projects that aim to sequence challenging, irreplaceable historical specimens. © 2017 John Wiley & Sons Ltd.

  5. Breast cancer: determining the genetic profile from ultrasound-guided percutaneous biopsy specimens obtained during the diagnostic workups.

    Science.gov (United States)

    López Ruiz, J A; Zabalza Estévez, I; Mieza Arana, J A

    2016-01-01

    To evaluate the possibility of determining the genetic profile of primary malignant tumors of the breast from specimens obtained by ultrasound-guided percutaneous biopsies during the diagnostic imaging workup. This is a retrospective study in 13 consecutive patients diagnosed with invasive breast cancer by B-mode ultrasound-guided 12 G core needle biopsy. After clinical indication, the pathologist decided whether the paraffin block specimens seemed suitable (on the basis of tumor size, validity of the sample, and percentage of tumor cells) before sending them for genetic analysis with the MammaPrint® platform. The size of the tumors on ultrasound ranged from 0.6cm to 5cm. In 11 patients the preserved specimen was considered valid and suitable for use in determining the genetic profile. In 1 patient (with a 1cm tumor) the pathologist decided that it was necessary to repeat the core biopsy to obtain additional samples. In 1 patient (with a 5cm tumor) the specimen was not considered valid by the genetic laboratory. The percentage of tumor cells in the samples ranged from 60% to 70%. In 11/13 cases (84.62%) it was possible to do the genetic analysis on the previously diagnosed samples. In most cases, regardless of tumor size, it is possible to obtain the genetic profile from tissue specimens obtained with ultrasound-guided 12 G core biopsy preserved in paraffin blocks. Copyright © 2015 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

  6. Freeze-Thaw Cycle Test on Basalt, Diorite and Tuff Specimens with the Simulated Ground Temperature of Antarctica

    Science.gov (United States)

    Park, J.; Hyun, C.; Cho, H.; Park, H.

    2010-12-01

    Physical weathering caused by freeze-thaw action in cold regions was simulated with artificial weathering simulator in laboratory. Physical weathering of rock in cold regions usually depends on the temperature, rock type and moisture content. Then these three variables were considered in this study. The laboratory freeze-thaw tests were conducted on the three types of rocks, e.g. diorite, basalt and tuff, which are the major rock types around Sejong Station, King George Island, Antarctica. Nine core samples composed of three samples from each rock type were prepared in NX core, and 50 cycles of freeze-thaw test was carried out under dried and saturated water conditions. In this study, the physical weathering of rocks was investigated after each 10 cycles by measuring P-wave velocity, bulk density, effective porosity, Schmidt hardness and uniaxial compression strength(UCS). The experimental result of the diorite and the tuff specimens showed that P-wave velocity, bulk density, effective porosity, Schmidt hardness and UCS were gradually decreased as weathering progresses, but the result of the basalt specimens did not show typical trends due to the characteristics of irregular pore distribution and various pore sizes. Scanning electron microscopy(SEM) photographs of diorite, basalt and tuff specimens weathered in dried and saturated conditions were also acquired to investigate the role of water during physical weathering processes. The number and size of microcracks were increased as weathering progresses. This work was supported by the National Research Foundation of Korea(NRF) Grant(NRF-2010-0027753).

  7. Humeral head size in shoulder arthroplasty

    DEFF Research Database (Denmark)

    Vaesel, M T; Olsen, Bo Sanderhoff; Søjbjerg, Jens Ole

    1998-01-01

    Changes in kinematics after hemiarthroplasty of the glenohumeral joint were investigated in nine cadaveric specimens. During experiments the influence of the humeral head size on glenohumeral kinematics was evaluated. A modular prosthesis with five different head sizes and press-fit stems was use...

  8. Use of miniature tensile specimen and video extensometer for measurement of mechanical properties

    International Nuclear Information System (INIS)

    Kumar, Kundan; Pooleery, Arun; Madhusoodanan, K.

    2014-08-01

    Miniaturisation of the tensile test specimen below the sub-size level poses various challenges, such as conformity of specimen to various acceptance criteria as per standard test specimen, aspect ratio, minimum number of grains required in a gauge cross-section, fabrication for uniformity in metrological values, etc. Apart from these, measurement of strain over a very limited available space on the test specimen is another practical challenge. Despite these limitations, miniature specimen testing is increasingly being used worldwide these days. The driving forces behind increasing use of miniature test techniques are new material development, assuring fitness of component after in-service-inspection, low dose of radiation exposure due to smaller dimensions of test specimens etc. However, the evaluation of mechanical properties from a miniature tensile test has a greater advantage over the other miniature novel test techniques, such as small punch test, ABI, miniature fatigue and impact tests etc., as it is a direct method of measurement of mechanical properties. This report covers various aspects of miniature tensile test methodologies, which include geometrical design of specimen having gauge length of 3-5 mm, fabrication, development of special fixtures for gripping the test specimens, and use of optical method for strain measurement. The geometrical design of the specimen and its behaviour over application of tensile load has been established using FEM analysis. A good agreement between conventional and miniature test results exemplifies the potential of the miniature tensile test technique. (author)

  9. Size effects in manufacturing of metallic components

    DEFF Research Database (Denmark)

    Vollertsen, F; Biermann, D; Hansen, Hans Nørgaard

    2009-01-01

    In manufacturing of metallic components, the size of the part plays an important role for the process behaviour. This is due to so called size effects, which lead to changes in the process behaviour even if the relationship between the main geometrical features is kept constant. The aim...... of this paper is to give a systematic review on Such effects and their potential use or remedy. First, the typology of size effects will be explained, followed by a description of size effects on strength and tribology. The last three sections describe size effects on formability, forming processes and cutting...... processes. (C) 2009 CIRP....

  10. Modelling the effect of size-asymmetric competition on size inequality

    DEFF Research Database (Denmark)

    Rasmussen, Camilla Ruø; Weiner, Jacob

    2017-01-01

    Abstract The concept of size asymmetry in resource competition among plants, in which larger individuals obtain a disproportionate share of contested resources, appears to be very straightforward, but the effects of size asymmetry on growth and size variation among individuals have proved...... to be controversial. It has often been assumed that competition among individual plants in a population has to be size-asymmetric to result in higher size inequality than in the absence of competition, but here we question this inference. Using very simple, individual-based models, we investigate how size symmetry...... of competition affects the development in size inequality between two competing plants and show that increased size inequality due to competition is not always strong evidence for size-asymmetric competition. Even absolute symmetric competition, in which all plants receive the same amount of resources...

  11. Dependency of annealing behaviour on grain size in Al–TiC ...

    Indian Academy of Sciences (India)

    This work investigates the effect of grain size on annealing behaviour in both coarse-grained and ultrafinegrained Al–TiC composite processed by accumulative roll bonding (ARB). Microstructural analysis indicates that annealingbehaviour of the specimens are essentially determined by the level of strain accumulation or ...

  12. Validatin of miniaturised tensile testing on DMLS TI6AL4V (ELI specimens

    Directory of Open Access Journals (Sweden)

    Van Zyl, Ian

    2016-11-01

    Full Text Available Direct metal laser sintering (DMLS is a relatively new technology that is developing rapidly. Since DMLS material is created by melting/solidifying tracks and layers from powder, even building geometry can influence the mechanical properties. To certify a material, the testing specimens must be designed and manufactured according to the appropriate standards. Miniaturised tensile DMLS samples could be a good alternative for express quality control, and could reduce the cost of DMLS-specific testing. In this study, as-built and stress-relieved miniaturised tensile DMLS Ti6Al4V (ELI specimens with different surface qualities were investigated. The fracture surfaces and mechanical properties of the mini-tensile specimens were analysed and compared with standard full-sized specimens also manufactured by DMLS. The obtained data showed the applicability of mini-tensile tests for the express analysis of DMLS objects if a correction factor is applied for the calculation of the load-bearing cross-section of the specimen.

  13. Fractographic examination of HT-9 and 9Cr-1Mo Charpy specimens irradiated in the AD-2 test

    International Nuclear Information System (INIS)

    Gelles, D.S.; Hu, W.L.

    1983-01-01

    Fracture surface topologies have been examined using scanning electron microscopy for 20 selected half sized Charpy impact specimens of HT-9 and Modified 9Cr-1Mo in order to provide improved understanding of fracture toughness degradation as a result of irradiation for Path E alloys. The specimen matrix included unirradiated specimens and specimens irradiated in EBR-II in the AD-2 experiment. Also, hardness measurements have been made on selected irradiated Charpy specimens. The results of examinations indicate that irradiation hardening due to G-phase formation at 390 0 C is responsible for the large shift in ductile-to-brittle transition temperature (DBTT) found in HT-9. Toughness degradation in HT-9 observed following higher temperature irradiations is attributed to precipitation at delta ferrite stringers. Reductions in toughness as a consequence of irradiation in Modified 9Cr-1Mo are attributed to in-reactor precipitation of (V,Nb)C and M 23 C 6 . It is shown that crack propagation rates for ductile and brittle failure modes can be measured, that they differ by over an order of magnitude and that unexpected multiple shifts in fracture mode from ductile to brittle failure can be attributed to the effect of delta ferrite stringers on crack propagation rates

  14. Effect size estimates: current use, calculations, and interpretation.

    Science.gov (United States)

    Fritz, Catherine O; Morris, Peter E; Richler, Jennifer J

    2012-02-01

    The Publication Manual of the American Psychological Association (American Psychological Association, 2001, American Psychological Association, 2010) calls for the reporting of effect sizes and their confidence intervals. Estimates of effect size are useful for determining the practical or theoretical importance of an effect, the relative contributions of factors, and the power of an analysis. We surveyed articles published in 2009 and 2010 in the Journal of Experimental Psychology: General, noting the statistical analyses reported and the associated reporting of effect size estimates. Effect sizes were reported for fewer than half of the analyses; no article reported a confidence interval for an effect size. The most often reported analysis was analysis of variance, and almost half of these reports were not accompanied by effect sizes. Partial η2 was the most commonly reported effect size estimate for analysis of variance. For t tests, 2/3 of the articles did not report an associated effect size estimate; Cohen's d was the most often reported. We provide a straightforward guide to understanding, selecting, calculating, and interpreting effect sizes for many types of data and to methods for calculating effect size confidence intervals and power analysis.

  15. Mismatch effect on CT specimen mechanical effect and consequences on the weld toughness characterization

    International Nuclear Information System (INIS)

    Marie, S.; Nedelec, M.

    2012-01-01

    The welded joints are particularly sensitive areas in the structures in terms of harmfulness of defects. Given the complexity of the problem (geometry poorly controlled, multi-material aspect, the potential influence of residual stresses), the tests are conducted based on pessimistic assumptions that can wrap all the uncertainties of the problem. In the case of a defect assessment, the considered toughness is deduced from conventional characterization tests with a crack in the welding, considering the current standards, ISO 12135 or ASTM E-1820 which are valid only for an homogeneous specimen. In 2010, a new standard ISO 16563 was published to address the specificity of welded joints. If it covers some of the difficulties, it remains incomplete. In nuclear piping, welds have a mismatch M, i.e. the ratio between the yield strength of the weld metal and the base metal, usually greater than 1: this avoids any problem of strain localization at the junction and ensure that the stresses in the base metal are also easily supported by the welded joint. In this configuration, it turns out that for a given mechanical loading, a crack in the weld located generally has a solicitation, quantified by the parameter J, less (depending on the size of the junction) to those that would see the same crack located in the base metal. Unfortunately, this phenomenon exists also potentially for a characterization test, which would overestimate the true toughness of the welded joint. Plasticity that develops from the crack tip can quickly reach this interface and be affected. To evaluate this phenomenon, we considered two types of representative welded joint (PWR secondary loop ferritic weld and a 316 stainless steel weld) and performed a F.E. analysis of the multi-material CT specimen mechanical answer and on the η coefficient conventionally used to derive the plastic component of J from the area under the curve force-opening displacement. (authors)

  16. Accuracy of computed tomography in determining pancreatic cancer tumor size

    International Nuclear Information System (INIS)

    Aoki, Kazunori; Okada, Shuichi; Moriyama, Noriyuki

    1994-01-01

    We compared tumor sizes determined by computed tomography (CT) with those of the resected specimens in 26 patients with pancreatic cancer in order to clarify whether or not the size of a pancreatic tumor can be accurately determined by CT. From the precontrast, postcontrast and arterial dominant phases of dynamic CT, the arterial dominant phase was found to yield the highest correlation between CT measured tumor size and that of the resected specimens (p<0.01). The correlation coefficient was, however, not high (r=0.67). CT alone may therefore be insufficient to determine tumor size in pancreatic cancer accurately. (author)

  17. Splitting tests on rock specimens

    Energy Technology Data Exchange (ETDEWEB)

    Davies, J D; Stagg, K G

    1970-01-01

    Splitting tests are described for a square-section sandstone specimens line loaded through steel or timber packings on the top face and supported on the bottom face either on similar packings (type A specimen) or directly on the lower platen plate of the testing machine (type B specimens). The stress distribution across the vertical central plane and the horizontal central plane were determined from a linear elastic finite element analysis for both types. Two solutions were obtained for the type B specimen: one assuming no friction between the base of the specimen and the platen plate and the other assuming no relative slip between the surfaces. Vertical and horizontal strains were measured at the center of the specimens for all loads up to failure.

  18. Do class size effects differ across grades?

    DEFF Research Database (Denmark)

    Nandrup, Anne Brink

    size cap that creates exogenous variation in class sizes. Significant (albeit modest) negative effects of class size increases are found for children on primary school levels. The effects on math abilities are statistically different across primary and secondary school. Larger classes do not affect......This paper contributes to the class size literature by analyzing whether short-run class size effects are constant across grade levels in compulsory school. Results are based on administrative data on all pupils enroled in Danish public schools. Identification is based on a government-imposed class...

  19. Laparoscopic specimen retrieval bags.

    Science.gov (United States)

    Smorgick, Noam

    2014-10-01

    Specimen retrieval bags have long been used in laparoscopic gynecologic surgery for contained removal of adnexal cysts and masses. More recently, the concerns regarding spread of malignant cells during mechanical morcellation of myoma have led to an additional use of specimen retrieval bags for contained "in-bag" morcellation. This review will discuss the indications for use retrieval bags in gynecologic endoscopy, and describe the different specimen bags available to date.

  20. Study of microstructure and fracture properties of blunt notched and sharp cracked high density polyethylene specimens.

    Science.gov (United States)

    Pan, Huanyu; Devasahayam, Sheila; Bandyopadhyay, Sri

    2017-07-21

    This paper examines the effect of a broad range of crosshead speed (0.05 to 100 mm/min) and a small range of temperature (25 °C and 45 °C) on the failure behaviour of high density polyethylene (HDPE) specimens containing a) standard size blunt notch and b) standard size blunt notch plus small sharp crack - all tested in air. It was observed that the yield stress properties showed linear increase with the natural logarithm of strain rate. The stress intensity factors under blunt notch and sharp crack conditions also increased linearly with natural logarithm of the crosshead speed. The results indicate that in the practical temperature range of 25 °C and 45 °C under normal atmosphere and increasing strain rates, HDPE specimens with both blunt notches and sharp cracks possess superior fracture properties. SEM microstructure studies of fracture surfaces showed craze initiation mechanisms at lower strain rate, whilst at higher strain rates there is evidence of dimple patterns absorbing the strain energy and creating plastic deformation. The stress intensity factor and the yield strength were higher at 25 °C compared to those at 45 °C.

  1. Preparation of ZiO2 specimens for transmission electron microscopy

    International Nuclear Information System (INIS)

    Bressiani, A.H.A.

    1987-01-01

    The determination of average grain size, of the presence of monoclinic, tetragonal and cubic phases, as well as their relative distributions are necessary for the study of several partially stabilized zirconia properties. However, the phase distributions can be changed during the preparation of specimens for transmission electron microscopy, yielding misleading results. In this work suitable preparation method is reported. (Author) [pt

  2. Effective porosity and pore-throat sizes of Conasauga Group mudrock: Application, test and evaluation of petrophysical techniques

    International Nuclear Information System (INIS)

    Dorsch, J.; Katsube, T.J.; Sanford, W.E.; Univ. of Tennessee, Knoxville, TN; Dugan, B.E.; Tourkow, L.M.

    1996-04-01

    Effective porosity (specifically referring to the interconnected pore space) was recently recognized as being essential in determining the effectiveness and extent of matrix diffusion as a transport mechanism within fractured low-permeability rock formations. The research presented in this report was performed to test the applicability of several petrophysical techniques for the determination of effective porosity of fine-grained siliciclastic rocks. In addition, the aim was to gather quantitative data on the effective porosity of Conasauga Group mudrock from the Oak Ridge Reservation (ORR). The quantitative data reported here include not only effective porosities based on diverse measurement techniques, but also data on the sizes of pore throats and their distribution, and specimen bulk and grain densities. The petrophysical techniques employed include the immersion-saturation method, mercury and helium porosimetry, and the radial diffusion-cell method

  3. Urine culture - catheterized specimen

    Science.gov (United States)

    Culture - urine - catheterized specimen; Urine culture - catheterization; Catheterized urine specimen culture ... urinary tract infections may be found in the culture. This is called a contaminant. You may not ...

  4. HMSRP Hawaiian Monk Seal Specimen Data (includes physical specimens, collection information, status, storage locations, and laboratory results associated with individual specimens)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set includes physical specimens, paper logs and Freezerworks database of all logged information on specimens collected from Hawaiian monk seals since 1975....

  5. Specimen's plane misaligned installation solution based on charge fluctuation inside SEM

    Science.gov (United States)

    Lu, Haojian; Liu, Yanting; Yang, Yuanyuan; Wang, Panbing; Shen, Yajing

    2018-04-01

    Precise specimen's installation is a sticking point to ensure the characterization accuracy of the in-situ material property test. Although it is common knowledge that specimen's plane misaligned installation (PMI) would cause extra force loading during mechanical testing, there are few effective solutions available to deal with it at the current stage, especially during the in-situ scanning electron microscopy (SEM) test. Taking into consideration the charge fluctuation phenomenon under SEM, this paper proposes a highlight area variation (HAV) method for specimen deformation judgment, i.e., the specimen deformation is defined when the highlight area changes greater than 20% of the initial value of the specimen surface. Three types of specimens with different resistivities, i.e., human hair (electrical resistivity ˜3 × 1012 Ω cm), optical fiber (electrical resistivity ˜1017 Ω cm), and magnetic wire (electrical resistivity ˜2 × 10-5 Ω cm), are chosen to verify the effectiveness of the HAV method. Furthermore, combined with the developed robot-aided alignment system, the specimen's PMI problem can also be solved. In the demonstration, the human hair specimen is installed across two specimen stages and its in-situ twisting (in 360°) test is implemented. The results clearly indicate that the HAV method and the robot-aided alignment system are practical and reliable, and the specimen can be aligned on the same plane and installed precisely with accuracy up to 3 μm. This method will benefit the in-situ SEM material mechanical property test and has a significant impact in fundamental material research.

  6. Integration of Value Stream Map and Healthcare Failure Mode and Effect Analysis into Six Sigma Methodology to Improve Process of Surgical Specimen Handling.

    Science.gov (United States)

    Hung, Sheng-Hui; Wang, Pa-Chun; Lin, Hung-Chun; Chen, Hung-Ying; Su, Chao-Ton

    2015-01-01

    Specimen handling is a critical patient safety issue. Problematic handling process, such as misidentification (of patients, surgical site, and specimen counts), specimen loss, or improper specimen preparation can lead to serious patient harms and lawsuits. Value stream map (VSM) is a tool used to find out non-value-added works, enhance the quality, and reduce the cost of the studied process. On the other hand, healthcare failure mode and effect analysis (HFMEA) is now frequently employed to avoid possible medication errors in healthcare process. Both of them have a goal similar to Six Sigma methodology for process improvement. This study proposes a model that integrates VSM and HFMEA into the framework, which mainly consists of define, measure, analyze, improve, and control (DMAIC), of Six Sigma. A Six Sigma project for improving the process of surgical specimen handling in a hospital was conducted to demonstrate the effectiveness of the proposed model.

  7. Publication Bias in Psychology: A Diagnosis Based on the Correlation between Effect Size and Sample Size

    Science.gov (United States)

    Kühberger, Anton; Fritz, Astrid; Scherndl, Thomas

    2014-01-01

    Background The p value obtained from a significance test provides no information about the magnitude or importance of the underlying phenomenon. Therefore, additional reporting of effect size is often recommended. Effect sizes are theoretically independent from sample size. Yet this may not hold true empirically: non-independence could indicate publication bias. Methods We investigate whether effect size is independent from sample size in psychological research. We randomly sampled 1,000 psychological articles from all areas of psychological research. We extracted p values, effect sizes, and sample sizes of all empirical papers, and calculated the correlation between effect size and sample size, and investigated the distribution of p values. Results We found a negative correlation of r = −.45 [95% CI: −.53; −.35] between effect size and sample size. In addition, we found an inordinately high number of p values just passing the boundary of significance. Additional data showed that neither implicit nor explicit power analysis could account for this pattern of findings. Conclusion The negative correlation between effect size and samples size, and the biased distribution of p values indicate pervasive publication bias in the entire field of psychology. PMID:25192357

  8. Impact of implant size on cement filling in hip resurfacing arthroplasty.

    Science.gov (United States)

    de Haan, Roel; Buls, Nico; Scheerlinck, Thierry

    2014-01-01

    Larger proportions of cement within femoral resurfacing implants might result in thermal bone necrosis. We postulate that smaller components are filled with proportionally more cement, causing an elevated failure rate. A total of 19 femoral heads were fitted with polymeric replicas of ReCap (Biomet) resurfacing components fixed with low-viscosity cement. Two specimens were used for each even size between 40 and 56 mm and one for size 58 mm. All specimens were imaged with computed tomography, and the cement thickness and bone density were analyzed. The average cement mantle thickness was 2.63 mm and was not correlated with the implant size. However, specimen with low bone density had thicker cement mantles regardless of size. The average filling index was 36.65% and was correlated to both implant size and bone density. Smaller implants and specimens with lower bone density contained proportionally more cement than larger implants. According to a linear regression model, bone density but not implant size influenced cement thickness. However, both implant size and bone density had a significant impact on the filling index. Large proportions of cement within the resurfacing head have the potential to generate thermal bone necrosis and implant failure. When considering hip resurfacing in patients with a small femoral head and/or osteoporotic bone, extra care should be taken to avoid thermal bone necrosis, and alternative cementing techniques or even cementless implants should be considered. This study should help delimiting the indications for hip resurfacing and to choose an optimal cementing technique taking implant size into account.

  9. The Coupled Effect of Loading Rate and Grain Size on Tensile Strength of Sandstones under Dynamic Disturbance

    Directory of Open Access Journals (Sweden)

    Miao Yu

    2017-01-01

    Full Text Available It is of significance to comprehend the effects of rock microstructure on the tensile strength under different loading rates caused by mining disturbance. So, in this paper, three kinds of sandstones drilled from surrounding rocks in Xiao Jihan Coal to simulate the in situ stress state, whose average grain size is 30 μm (fine grain, FG, 105 μm (medium grain, MG, and 231 μm (Coarse grain, CG, are selected with the calculation of optical microscopic technique and moreover processed to Brazilian disc (BD to study the mechanical response of samples. The dynamic Brazilian tests of samples with three kinds of grain sizes are conducted with the Split Hopkinson Pressure Bar (SHPB driven by pendulum hammer, which can produce four different velocities (V=2.0 m/s, 2.5 m/s, 3.3 m/s, and 4.2 m/s when the incident bar is impacted by pendulum hammer. The incident wave produced by pendulum hammer is a slowly rising stress wave, which allows gradual stress accumulation in the specimen and maintains the load at both ends of the specimen in an equilibrium state. The results show that the dynamic strength of three kinds of BD samples represented loading rates dependence, and FG sandstones are more sensitive for loading rates than MG and CG samples. Moreover, the peak strength is observed to increase linearly with an increasing stress rates, and the relationship between the dynamic BD strength and stress rates can be built through a linear equation. Finally, the failure modes of different grain sizes are discussed and explained by microfailure mechanism.

  10. The distinct element analysis for swelling pressure test of bentonite. Discussion on the effects of wall friction force and aspect ratio of specimen

    International Nuclear Information System (INIS)

    Shimizu, Hiroyuki; Kikuchi, Hirohito; Fujita, Tomoo; Tanai, Kenji

    2011-10-01

    For geological isolation systems for radioactive waste, bentonite based material is assumed to be used as a buffer material. The swelling characteristics of the bentonite based material are expected to fill up the void space around the radioactive wastes by swelling. In general, swelling characteristics and properties of bentonite are evaluated by the laboratory tests. However, due to the lack of standardization of testing method for bentonite, the accuracy and reproducibility of the testing results are not sufficiently proved. In this study, bentonite swelling pressure test were simulated by newly developed Distinct Element Method (DEM) code, and the effects of wall friction force and aspect ratio of bentonite specimen were discussed. As a result, the followings were found. In the beginning of the swelling pressure test, since swelling occurs only around the fluid injection side of the specimen, wall friction force acts only in the swelling area and the specimen moves to opposite side from fluid injection side. However, when the entire specimen started swelling, displacement of the specimen prevented by the wall friction force, and the specimen is pressed against the pressure measurement side. Then, the swelling pressure measured on the pressure measurement side increases. Such displacement in the specimen is significantly affected by the decreasing of mechanical properties and the difference of saturation in the bentonite specimen during the fluid infiltration. Moreover, when the aspect ratio of the specimen is large, the displacement of the particle in the specimen becomes large and the area on which the wall frictional force acts is also large. Therefore, measured swelling pressure increases more greatly as the aspect ratio of the specimen increases. To contributes to the standardization of laboratory test methods for bentonite, these effects of wall friction force revealed by the DEM simulation should be verified through laboratory experiments. (author)

  11. Plastic zone size for nanoindentation of irradiated Fe–9%Cr ODS

    Energy Technology Data Exchange (ETDEWEB)

    Dolph, Corey K. [Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Silva, Douglas J. da [Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Federal University of São Carlos, Rodovia Washington Luís, km 235 - SP-310, São Carlos, São Paulo (Brazil); Swenson, Matthew J. [Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Wharry, Janelle P., E-mail: jwharry@purdue.edu [Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Purdue University, 400 Central Drive, West Lafayette, IN 47907 (United States)

    2016-12-01

    The objective of this study is to determine irradiation effects on the nanoindentation plastic zone morphology in a model Fe–9%Cr ODS alloy. Specimens are irradiated to 50 displacements per atom at 400°C with Fe{sup ++} self-ions or to 3 dpa at 500°C with neutrons. The as-received specimen is also studied as a control. The nanoindentation plastic zone size is calculated using two approaches: (1) an analytical model based on the expanding spherical cavity analogy, and (2) finite element modeling (FEM). Plastic zones in all specimen conditions extend radially outward from the indenter, ∼4–5 times the tip radius, indicative of fully plastic contact. Non-negligible plastic flow in the radial direction requires the experimentalist to consider the plastic zone morphology when nanoindenting ion-irradiated specimens; a single nanoindent may sample non-uniform irradiation damage, regardless of whether the indent is made top-down or in cross-section. Finally, true stress-strain curves are generated.

  12. Blood specimen labelling errors: Implications for nephrology nursing practice.

    Science.gov (United States)

    Duteau, Jennifer

    2014-01-01

    Patient safety is the foundation of high-quality health care, as recognized both nationally and worldwide. Patient blood specimen identification is critical in ensuring the delivery of safe and appropriate care. The practice of nephrology nursing involves frequent patient blood specimen withdrawals to treat and monitor kidney disease. A critical review of the literature reveals that incorrect patient identification is one of the major causes of blood specimen labelling errors. Misidentified samples create a serious risk to patient safety leading to multiple specimen withdrawals, delay in diagnosis, misdiagnosis, incorrect treatment, transfusion reactions, increased length of stay and other negative patient outcomes. Barcode technology has been identified as a preferred method for positive patient identification leading to a definitive decrease in blood specimen labelling errors by as much as 83% (Askeland, et al., 2008). The use of a root cause analysis followed by an action plan is one approach to decreasing the occurrence of blood specimen labelling errors. This article will present a review of the evidence-based literature surrounding blood specimen labelling errors, followed by author recommendations for completing a root cause analysis and action plan. A failure modes and effects analysis (FMEA) will be presented as one method to determine root cause, followed by the Ottawa Model of Research Use (OMRU) as a framework for implementation of strategies to reduce blood specimen labelling errors.

  13. Nanocoatings size effect in nanostructured films

    CERN Document Server

    Aliofkhazraei, Mahmood

    2014-01-01

    Size effect in structures has been taken into consideration over the last years. In comparison with coatings with micrometer-ranged thickness, nanostructured coatings usually enjoy better and appropriate properties, such as strength and resistance. These coatings enjoy unique magnetic properties and are used with the aim of producing surfaces resistant against erosion, lubricant system, cutting tools, manufacturing hardened sporadic alloys, being resistant against oxidation and corrosion. This book reviews researches on fabrication and classification of nanostructured coatings with focus on size effect in nanometric scale. Size effect on electrochemical, mechanical and physical properties of nanocoatings are presented.

  14. Integration of Value Stream Map and Healthcare Failure Mode and Effect Analysis into Six Sigma Methodology to Improve Process of Surgical Specimen Handling

    Directory of Open Access Journals (Sweden)

    Sheng-Hui Hung

    2015-01-01

    Full Text Available Specimen handling is a critical patient safety issue. Problematic handling process, such as misidentification (of patients, surgical site, and specimen counts, specimen loss, or improper specimen preparation can lead to serious patient harms and lawsuits. Value stream map (VSM is a tool used to find out non-value-added works, enhance the quality, and reduce the cost of the studied process. On the other hand, healthcare failure mode and effect analysis (HFMEA is now frequently employed to avoid possible medication errors in healthcare process. Both of them have a goal similar to Six Sigma methodology for process improvement. This study proposes a model that integrates VSM and HFMEA into the framework, which mainly consists of define, measure, analyze, improve, and control (DMAIC, of Six Sigma. A Six Sigma project for improving the process of surgical specimen handling in a hospital was conducted to demonstrate the effectiveness of the proposed model.

  15. Structural effect of size on interracial friendship.

    Science.gov (United States)

    Cheng, Siwei; Xie, Yu

    2013-04-30

    Social contexts exert structural effects on individuals' social relationships, including interracial friendships. In this study, we posit that, net of group composition, total context size has a distinct effect on interracial friendship. Under the assumptions of (i) maximization of preference in choosing a friend, (ii) multidimensionality of preference, and (iii) preference for same-race friends, we conducted analyses using microsimulation that yielded three main findings. First, increased context size decreases the likelihood of forming an interracial friendship. Second, the size effect increases with the number of preference dimensions. Third, the size effect is diluted by noise, i.e., the random component affecting friendship formation. Analysis of actual friendship data among 4,745 American high school students yielded results consistent with the main conclusion that increased context size promotes racial segregation and discourages interracial friendship.

  16. Production of iodine-123 radiobiological specimen on 25 MeV electron beam

    International Nuclear Information System (INIS)

    Oganesyan, Yu.Ts.; Starodub, G.Ya.; Buklanov, G.V.; Korotkin, Yu.S.; Belov, A.G.

    1988-01-01

    The technique is described and experimental results are presented for production of radioactive specimen-iodine-123 for medical biological investigations. It is shown that in ten hour irradiation of 124 Xe enriched target of 10 g weight by the 25 MeV electron beam at MT-25 microtron short lived 123 I with activity of about 200 mCl can be accumulated. The procedure was developed for extraction of radioactive atoms and preparing the solution that permits to obtain during 1-1.5 h after the end of irradiation the specimen which satisfies all pharmacopeia requirements. It follows from the results that using small-size electron accelerators with the beam energy up to 25 MeV permits to organize economical and large-scale production of high quality radioactive specimen of 123 I for servicing a large region of this country. 14 refs.; 4 figs.; 1 tab

  17. Effect of reverse cyclic loading on the fracture resistance curve in C(T) specimen

    International Nuclear Information System (INIS)

    Sung Seok, C.; Jin Kim, Y.; Il Weon, J.

    1999-01-01

    Fracture resistance (J-R) curves, which are used for elastic-plastic fracture mechanics analyses, are known to be dependent on the cyclic loading history. The objective of this paper is to investigate the effect of reverse cyclic loading on the J-R curves in C(T) specimens. The effect of two parameters was observed on the J-R curves during the reverse cyclic loading. One was the minimum-to-maximum load ratio (R) and the other was the incremental plastic displacement (δ cycle /δ i ), which is related to the amount of crack growth that occurs in a cycle. Fracture resistance tests on C(T) specimens with varying the load ratio and the incremental plastic displacement were performed, and the test results showed that the J-R curves were decreased with decreasing the load ratio and decreasing the incremental plastic displacement. Direct current potential drop (DCPD) method was used for the detection of crack initiation and crack growth in typical laboratory J-R tests. The values of crack initiation J-integral (J I ) and crack initiation displacement (δ i ) were also obtained by using the DCPD method. (orig.)

  18. Effect of monitoring strategies and reference data of the German Environmental Specimen Banking Program

    International Nuclear Information System (INIS)

    Paulus, M.; Bartel, M.; Klein, R.; Nentwich, K.; Quack, M.; Teubner, D.; Wagner, G.

    2005-01-01

    The constitution of the German Environmental Specimen Bank (ESB) has started in 1985, subsequent to a successful pilot study concerning the feasibility. Since that time, a multitude of technological and methodical standards have been developed, which allow for a high quality of the storage-samples and of the specimen characterization. While the storage-samples are kept for retrospective analysis, by now, already comprehensive data on the material-developing in the environment are available due to a real time monitoring of selected environmental chemicals over a period of up to twenty years. Thus, spatial and temporal trends can be described. Since the state of knowledge on critical tissue concentrations in the sublethal range is extremely low at present, it is however not possible to accomplish a direct assessment of relevancy of the substance concentrations. Hence, within the scope of the German ESB Program, the following strategies on assessment of relevancy are observed: use of biomarkers, histopathological examinations, biometric specimen characterization, use of ecological indicator groups, and development of a reference system with analytical and biometric data. Thus, for example endocrine effects in male breams in the river Saar, which correlate directly to operational discharges from municipal sewage plants, could be detected. By histopathological examinations, fibrotic and necrotic tissue adaptations on the gonads had been ascertained cumulatively, which unambiguously imply a restricted fertility of the male breams. In the river Rhine, an improved growth along the timeline could be described on the basis of biometric characterization of breams, which is regarded as rate for the reaction to all structural and material changes in the water body. Presently, with the development of a reference system based on the data collected in the scope of the Environmental Specimen Bank, a basis for the assessment of monitoring results with accumulation indicators is

  19. Material Models to Study the Bauschinger Effect on an Aluminum Shear Test Specimen

    International Nuclear Information System (INIS)

    Cardoso, Rui P. R.; Gracio, Jose J.; Yoon, Jeong-Whan

    2007-01-01

    Sheet metal forming processes generally involve complex loadings and nonlinear material models. Combinations of drawing, re-drawing and/or reverse drawing operations commonly induce cyclic loads with non-proportional strain paths, leading to Bauschinger effects that can not be predicted by conventional isotropic hardening laws. In order to properly represent this effect, it is also required to accommodate an appropriate kinematic hardening model along with an anisotropic yield function. In this work, two different approaches will be used to predict the Bauschinger effect for an Aluminum shear test specimen: the rate dependent crystal plasticity model and a new combined isotropic/kinematic hardening model based on the two yield surfaces approach (loading and boundary yield surfaces), as recently proposed

  20. The role of specimen temperature difference in the elevated temperature pitting/transfer of PE16 and 20/25/Nb SS during impact wear

    International Nuclear Information System (INIS)

    Morri, J.

    1989-01-01

    A previous study of the impact fretting wear characteristics of PE16 + impacting 20/25 Nb SS (carried out on the BNL twin vibrator rig) identified a pitting-transfer form of wear at 480 0 C. This behaviour was thought to be dependent upon the temperature difference ΔT(ΔT = T 20/25 -T PE 16 ) between the two specimens. In that series of tests, however, no localised temperature control over the specimens was possible and specimen temperature effects could only be assessed by interchanging their positions in the rig. The introduction of locally positioned auxilliary heaters permitted a degree of control over the specimen temperature difference. The effect of ΔT upon pitting and transfer of the PE16 and 20/25 was then assessed and is reported in this paper. The study confirmed that the pitting transfer process was dependent on the temperature difference between the two surfaces. The direction and size of the transfer/pitting effect was independent of the material. Under the particular set of conditions employed in the test, pitting occurred only when the magnitude of ΔT exceeded 20 0 C. At high ΔT the initial period of high friction was extended and was associated with the tendency for gross transfer and pitting. (author)

  1. Specimen alignment in an axial tensile test of thin films using direct imaging and its influence on the mechanical properties of BeCu

    International Nuclear Information System (INIS)

    Kang, Dong-Joong; Park, Jun-Hyub; Shin, Myung-Soo; Ha, Jong-Eun; Lee, Hak-Joo

    2010-01-01

    This paper proposes a new system for verification of the alignment of loading fixtures and test specimens during tensile testing of thin film with a micrometer size through direct imaging. The novel and reliable image recognition system to evaluate the misalignment between the load train and the specimen axes during tensile test of thin film was developed using digital image processing technology with CCD. The decision of whether alignment of the tensile specimen is acceptable or not is based on a probabilistic analysis through the edge feature extraction of digital imaging. In order to verify the performance of the proposed system and investigate the effect of the misalignment of the specimen on tensile properties, the tensile tests were performed as displacement control in air and at room temperature for metal thin film, the beryllium copper (BeCu) alloys. In the case of the metal thin films, bending stresses caused by misalignment are insignificant because the films are easily bent during tensile tests to eliminate the bending stresses. And it was observed that little effects and scatters on tensile properties occur by stress gradient caused by twisting at in-plane misalignment, and the effects and scatters on tensile properties are insignificant at out-of-plane misalignment, in the case of the BeCu thin film.

  2. Influence of specimen size and grain orientation to the life of a polycrystalline Ni-base alloy at LCF stress; Einfluss der Probengroesse und der Kornorientierung auf die Lebensdauer einer polykristallinen Ni-Basislegierung bei LCF-Beanspruchung

    Energy Technology Data Exchange (ETDEWEB)

    Seibel, Thomas

    2014-07-01

    In the present work the LCF (Low Cycle Fatigue) crack initiation life of the conventionally cast Ni-base alloy RENE 80 was analyzed as a function of specimen size and grain orientation. Five specimen geometries with distinctly different gauge sections were used: 3 geometries with cylindrical gauge section (G1-G3) and two notched geometries with a stress concentration factor of α{sub 1} = 1,62 (KG1) and α{sub 2} = 2,60 (KG2), resulting in a maximum difference of the damage relevant surface area up to a factor of approximately 72. Correction factors were determined by FEM calculations for all specimen geometries with highly reduced gauge sections where direct strain measurement was not possible. Additionally a uniform failure criterion with a relatively small crack size of 0,962 mm{sup 2} was defined. Totally, 116 isothermal LCF tests were carried out at the different specimen types at a temperature of 850 C in total strain control with a load ratio (minimum strain / maximum strain) of R{sub ε} = -1. The load cycles were applied with triangular waveform at a frequency of 0.1 Hz for high strain amplitudes and 1 Hz for low strain amplitudes, respectively. After the LCF-Tests the fracture surfaces of all samples were analyzed in more detail by SEM to identify the crack initiation mechanisms as well as the crack initiation sites. In this context it could be shown, that fatigue cracks were generally initiated at slip bands in surface grains. Accordingly, the grain orientations at the crack initiation sites were measured by electron back scatter diffraction (EBSD) and the maximum shear stresses in the respective principal slip system (111) <110> was calculated using the Schmid approach. For this, longitudinal sections were be prepared exactly at the crack initiation sites of samples loaded with low strain amplitudes where clearly defined single crack initiation sites were observed. Afterwards the maximum shear stress in the principal slip system at the crack initiation

  3. Screen-film specimen radiography

    International Nuclear Information System (INIS)

    Shepard, S.J.; Hogan, J.; Schreck, B.

    1990-01-01

    This paper reports on the reproducibility and quality of biopsy specimen radiographs, a unique phototimed cabinet x-ray system is being developed. The system utilizes specially modified Kodal Min-R cassettes and will be compatible with current mammographic films. Tube voltages are in the 14-20-kVp range with 0.1-1.0-second exposure times. A top-hat type compression device is used (1) to compress the specimen to uniform thickness, (2) to measure the specimen thickness and determine optimum kVp, and (3) to superimpose a grid over the specimen for identification of objects of radiographic interest. The phototiming circuit developed specifically for this purpose will be described along with the modified Min-R cassette. Characteristics of the generator and cabinet will also be described. Tests will be performed on phantoms to evaluate the system limitations

  4. Centrifuge-operated specimen staining method and apparatus

    Science.gov (United States)

    Clarke, Mark S. F. (Inventor); Feeback, Daniel L. (Inventor)

    1999-01-01

    A method of staining preselected, mounted specimens of either biological or nonbiological material enclosed within a staining chamber where the liquid staining reagents are applied and removed from the staining chamber using hypergravity as the propelling force. In the preferred embodiment, a spacecraft-operated centrifuge and method of diagnosing biological specimens while in orbit, characterized by hermetically sealing a shell assembly. The assembly contains slide stain apparatus with computer control therefor, the operative effect of which is to overcome microgravity, for example on board an International Space Station.

  5. A 3D dislocation dynamics analysis of the size effect on the strength of [1 1 1] LiF micropillars at 300K and 600K

    Science.gov (United States)

    Chang, Hyung-Jun; Segurado, Javier; Molina-Aldareguía, Jon M.; Soler, Rafael; LLorca, Javier

    2016-03-01

    The mechanical behavior in compression of [1 1 1] LiF micropillars with diameters in the range 0.5 μm to 2.0 μm was analyzed by means of discrete dislocation dynamics at ambient and elevated temperature. The dislocation velocity was obtained from the Peach-Koehler force acting on the dislocation segments from a thermally-activated model that accounted for the influence of temperature on the lattice resistance. A size effect of the type ‘smaller is stronger’ was predicted by the simulations, which was in quantitative agreement with previous experimental results by the authors [1]. The contribution of the different physical deformation mechanisms to the size effect (namely, nucleation of dislocations, dislocation exhaustion and forest hardening) could be ascertained from the simulations and the dominant deformation mode could be assessed as a function of the specimen size and temperature. These results shed light into the complex interaction among size, lattice resistance and dislocation mobility in the mechanical behavior of μm-sized single crystals.

  6. Molecular markers: Implications for cytopathology and specimen collection.

    Science.gov (United States)

    VanderLaan, Paul A

    2015-08-01

    Cytologic specimens obtained through minimally invasive biopsy techniques are increasingly being used as principle diagnostic specimens for tumors arising in multiple sites. The number and scope of ancillary tests performed on these specimens have grown substantially over the past decade, including many molecular markers that not only can aid in formulating accurate and specific diagnoses but also can provide prognostic or therapeutic information to help direct clinical decisions. Thus, the cytopathologist needs to ensure that adequate material is collected and appropriately processed for the study of relevant molecular markers, many of which are specific to tumor site. This brief review covers considerations for effective cytologic specimen collection and processing to ensure diagnostic and testing success. In addition, a general overview is provided of molecular markers pertinent to tumors from a variety of sites. The recognition of these established and emerging molecular markers by cytopathologists is an important step toward realizing the promise of personalized medicine. © 2015 American Cancer Society.

  7. Influence of impacts on static and low-cycle fatigue characteristics of composite specimens (Draft)

    NARCIS (Netherlands)

    Walters, C.L.

    2012-01-01

    This paper describes the effect of impacts on the possible reduction of the structural characteristics and damage growth of graphite-epoxy specimens. The considered specimens are undamaged specimens and specimens impacted with two different energy levels. In particular, barely visible impact damage

  8. Tumor containing fragment number influences immunohistochemistry positive rate of HER2 in biopsy specimens of gastric cancer.

    Science.gov (United States)

    Xu, Chen; Liu, Yalan; Ge, Xiaowen; Jiang, Dongxian; Zhang, Ying; Ji, Yuan; Hou, Jun; Huang, Jie; Su, Jieakesu; Zeng, Haiying; Qin, Jing; Hou, Yingyong

    2017-05-26

    HER2 assessment in biopsy specimens of gastric cancer (GC) is challenging because of the intratumoral heterogeneity. False negative results may be get because of limited biopsy material. The aim of this study is to explore how tumor-containing fragment number and biopsy specimen number affect HER2 immunohistochemistry (IHC) positive rate. Eight hundred and ninety biopsy specimens and 459 paired resected specimens were collected. IHC staining of HER2 was performed. HER2 IHC positive (scored 3+) rate was compared based on tumor-containing fragment number, biopsy specimen number, average size and tumor tissue proportion of tumor-containing fragments. The positive predictability of biopsy specimens to resected specimens was analyzed based on tumor fragment number. HER2 IHC positive rates were 2.0, 3.5, 7.0, 13.2, 17.1, and 15.9% when tumor fragment numbers were 1, 2, 3, 4, 5 and 6 respectively. The rate rose with the increase of tumor fragment number (P = 0.004). ROC curve analysis showed that biopsy specimens exhibited positive predictability when tumor fragment number reached 3, but showed better performance when the number was ≥4 (P fragment number reached 4, no statistic differences were reached in either HER2 IHC positive rate or positive predictability with further increase of the number (P > 0.05). HER2 IHC positive rate was not associated with biopsy number (P = 0.127), average size of tumor fragments (P = 0.397), and tumor tissue proportion of tumor fragments (P = 0.825) directly. The number of tumor-containing fragments influences HER2 IHC positive (scored 3+) rate. Greater than or equal to 4 (≥4) tumor fragments give better results in the positive rate as well as positive predictability. We recommend the number of tumor containing fragments be described in the HER2 IHC pathology reports for clinical reference in endoscopic biopsy specimens of GC.

  9. Effect of Different Peat Size and Pre-Consolidation Pressure of Reconstituted Peat on Effective Undrained Shear Strength Properties

    Science.gov (United States)

    Azhar, ATS; Norhaliza, W.; Ismail, B.; Ezree, AM; Nizam, ZM

    2017-08-01

    Shear strength of the soil is one of the most important parameters in engineering design, especially during the pre- or post-construction periods, since it is mainly used to measure and evaluate the foundation or slope stability of soil. Peat normally known as a soil that has a very low value of shear strength, and in order to determine and understand the shear strength of the peat, it is a difficult task in geotechnical engineering due to several factors such as types of fabrics, the origin of the soil, water content, organic matter and the degree of humification. The aim of this study is to determine the effective undrained shear strength properties of reconstituted peat of different sizes. All the reconstituted peat samples were formed with the size that passed the opening sieve of 0.425 mm (effective undrained shear strength properties for reconstituted peat effective shear strength properties for the reconstituted peat effective undrained shear strength properties result obtained from the tests show that the reconstituted peat pore pressure, Δu, show both of specimen. The physical properties of the reconstituted peat

  10. Practical Approaches to Mitigation of Specimen Charging in High-Resolution Transmission Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Young-Min Kim

    2010-09-01

    Full Text Available Specimen charging that is associated with the electron bombardment on the sample is a practical hindrance to high-resolution transmission electron microscopy (HRTEM analysis because it causes a severe loss of resolution in either diffraction or image data. Conductive thin film deposition on an insulating specimen has been proposed as an effective approach to the mitigation of the specimen charging; however, this method is generally not useful in HRTEM imaging of materials because the deposited film induces another artifact in the HRTEM image contrast. In this study, we propose practical methods to mitigate the specimen charging that takes place during the HRTEM of materials. For bulk-type specimens prepared by either an ion-thinning or focused-ion beam (FIB process, a plasma cleaning treatment is significantly effective in eliminating the charging phenomenon. In the case of low-dimensional nanomaterials such as nanowires and nanoparticles, the plasma cleaning is not feasible; however, the charging effect can be effectively eliminated by adjusting the electron illumination condition. The proposed methods facilitate a decrease in the buildup of specimen charging, thereby enhancing the quality of high-resolution images significantly.

  11. Size effect in the strength of concrete structures

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    The fracture mechanics size effect, as opposed to the Weibull statistical size effect, is a .... Solutions for TPB beam and a typical wedge-splitting geometry have been ..... Bazant Z P 1984 Size effect in blunt fracture: Concrete, rock, metal. J. Eng.

  12. Proton irradiation effects on tensile and bend-fatigue properties of welded F82H specimens

    Energy Technology Data Exchange (ETDEWEB)

    Saito, S., E-mail: saito.shigeru@jaea.go.j [JAEA Tokai, J-PARC Center, 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Kikuchi, K.; Hamaguchi, D. [JAEA Tokai, J-PARC Center, 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Usami, K.; Ishikawa, A.; Nishino, Y.; Endo, S. [JAEA Tokai, Department of Hot Laboratories, Tokai-mura, Ibaraki-ken 319-1195 (Japan); Kawai, M. [KEK, Tsukuba-shi, Ibaraki-ken 305-0801 (Japan); Dai, Y. [PSI, Spallation Source Division, 5232 Villigen PSI (Switzerland)

    2010-03-15

    In several institutes, research and development for an accelerator-driven transmutation system (ADS) have been progressed. Ferritic/martensitic (FM) steels are the candidate materials for the beam window of ADS. To evaluate of the mechanical properties of the irradiated materials, the post irradiation examination (PIE) work of the SINQ (Swiss spallation neutron source) target irradiation program (STIP) specimens was carried out at JAEA. In present study, the results of PIE on FM steel F82H and its welded joint have been reported. The present irradiation conditions of the specimens were as follows: proton energy was 580 MeV. Irradiation temperatures were ranged from 130 to 380 deg. C, and displacement damage level was ranged from 5.7 to 11.8 dpa. The results of tensile tests performed at 22 deg. C indicated that the irradiation hardening occurred with increasing the displacement damage up to 10.1 dpa at 320 deg. C irradiation. At higher dose (11.8 dpa) and higher temperature (380 deg. C), irradiation hardening was observed, but degradation of ductility was relaxed in F82H welded joint. In present study, all specimens kept its ductility after irradiation and fractured in ductile manner. The results on bend-fatigue tests showed that the fatigue life (N{sub f}) of F82H base metal irradiated up to 6.3 dpa was almost the same with that of unirradiated specimens. The N{sub f} of the specimens irradiated up to 9.1 dpa was smaller than that of unirradiated specimens. Though the number of specimen was limited, the N{sub f} of F82H EB (15 mm) and EB (3.3 mm) welded joints seemed to increase after irradiation and the fracture surfaces of the specimens showed transgranular morphology. While F82H TIG welded specimens were not fractured by 10{sup 7} cycles.

  13. Multi-detector row CT colonography: effect of collimation, pitch, and orientation on polyp detection in a human colectomy specimen.

    Science.gov (United States)

    Taylor, Stuart A; Halligan, Steve; Bartram, Clive I; Morgan, Paul R; Talbot, Ian C; Fry, Nicola; Saunders, Brian P; Khosraviani, Kirosh; Atkin, Wendy

    2003-10-01

    To investigate the effects of orientation, collimation, pitch, and tube current setting on polyp detection at multi-detector row computed tomographic (CT) colonography and to determine the optimal combination of scanning parameters for screening. A colectomy specimen containing 117 polyps of different sizes was insufflated and imaged with a multi-detector row CT scanner at various collimation (1.25 and 2.5 mm), pitch (3 and 6), and tube current (50, 100, and 150 mA) settings. Two-dimensional multiplanar reformatted images and three-dimensional endoluminal surface renderings from the 12 resultant data sets were examined by one observer for the presence and conspicuity of polyps. The results were analyzed with Poisson regression and logistic regression to determine the effects of scanning parameters and of specimen orientation on polyp detection. The percentage of polyps that were detected significantly increased when collimation (P =.008) and table feed (P =.03) were decreased. Increased tube current resulted in improved detection only of polyps with a diameter of less than 5 mm. Polyps of less than 5 mm were optimally depicted with a collimation of 1.25 mm, a pitch of 3, and a tube current setting of 150 mA; polyps with a diameter greater than 5 mm were adequately depicted with 1.25-mm collimation and with either pitch setting and any of the three tube current settings. Small polyps in the transverse segment (positioned at a 90 degrees angle to the z axis of scanning) were significantly less visible than those in parallel or oblique orientations (P detector row CT is highly dependent on collimation, pitch, and, to a lesser extent, tube current. Collimation of 1.25 mm, combined with pitch of 6 and tube current of 50 mA, provides for reliable detection of polyps 5 mm or larger while limiting the effective radiation dose. Polyps smaller than 5 mm, however, may be poorly depicted with use of these settings in the transverse colon. Copyright RSNA, 2003

  14. Prevention of the Portion Size Effect

    NARCIS (Netherlands)

    I. Versluis (Iris)

    2016-01-01

    markdownabstractAn increase in the portion size leads to an increase in energy intake, a phenomenon which is also referred to as the portion size effect. The increase in portion sizes in recent years is regarded as an important contributor to the increase in the prevalence of obesity. Hence, the aim

  15. Particle size effect on formation and stability of β-La2Mo2O9 ionic conductor

    International Nuclear Information System (INIS)

    Rocha, R.A.; Muccillo, E.N.S.

    2007-01-01

    The La 2 Mo 2 O 9 compound was prepared by thermal crystallization from a mixed nitrate solution to obtain a precursor material with different particle size than that obtained by the conventional mixing of starting oxides. This precursor material was characterized by several techniques before and after thermal decomposition into the final compound. X-ray diffraction and electron microscopy results evidence the formation of the high-temperature β-La 2 Mo 2 O 9 phase after calcination at 550 deg. C . The well-known α-to-β phase transition was detected at temperatures lower than that for powders prepared from mixing of starting oxides. Electrical conductivity measurements at several oxygen partial pressures show that specimens prepared from nitrates have a different behavior when compared to those specimens obtained by the conventional route. The overall results reveal the role of particle size of the precursor material on phase transition and stability of sintered La 2 Mo 2 O 9

  16. Effect of coarse {gamma} grain size on the dynamic and static recrystallisation during hot working in microalloyed Nb and Nb-Ti steels

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A.I.; Abad, R.; Lopez, B.; Rodriguez-Ibabe, J.M. [Centro de Estudios e Investigaciones Tecnicas de Guipuzcoa (CEIT), San Sebastian (Spain)

    1998-10-01

    The effect of coarse austenite grain size on the dynamic and static recrystallisation kinetics of two microalloyed Nb and Nb-Ti steels has been investigated in the present work. To characterize the dynamic recrystallisation behaviour of the austenite, continuous-torsion tests were carried out after the reheating of the specimen at different temperatures in the range 1000-1420 C. It has been observed that the occurrence of dynamic recrystallisation is dependent on the initial grain size and the deformation conditions (temperature and strain-rate). Decreasing values of the Zener-Hollomon parameter (Z) and grain size promotes dynamic recrystallisation. However for the coarser grain sizes no peaks appear on the flow curves above a determined value of Z. This value seems to decrease with increasing the grain size. An equation to predict the {epsilon}{sub p} peak strain for a wide range of grain sizes has been obtained for both steels. The effect of strain on the static recrystallisation of the austenite, having a large grain size, has been also studied. Interrupted-torsion tests were performed to determined the fractional softening. A quadratic dependence of t{sub 0.5} on strain has been observed, denoting a less dependence of recrystallisation on strain than proposed previously by other authors in the range of lower grain sizes. (orig.) 22 refs.

  17. The Impact of Storage Times of Museum Insect Specimens on PCR Success: Case Study on Moth Collections in Indonesia

    Directory of Open Access Journals (Sweden)

    HARI SUTRISNO

    2012-06-01

    Full Text Available Museum specimens are vast repositories of genetic information of interests to biological researchers. Since a new method in DNA extraction, a non destructive method, has been reported to be successful in extracting DNA of museum specimens even fossils without any morphological damages, using museum specimens as resources of genetic information for molecular studies is becoming popular recently. However, the PCR success depends on the quality of the specimens. To evaluate the impact of the storage times of museum specimens on PCR success, we conducted DNA extraction of 14 dry museum specimens of the moths collected from 1992 to 2010 by using a non destructive method. The results showed that the DNA specimens museum were fragmented into various sizes (100-1000 bp depend on the storage times. On the other hand, fresh specimens which were preserved within absolute ethanol were almost not fragmented. The specimens of < 6 years old (2005-2010 succeed to amplify in 650 bp amplicon but for some specimens of 7 years old (2 of 3 specimens resulted in a very weak amplification. These specimens, however, were able to amplify strongly in 300 bp amplicon. The results also showed that specimens of 1-19 years old were success to amplify in 100 bp amplicon.

  18. Effect of microstructure on shape memory effect and transformation behavior in an Fe-32Mn-6.5Si alloy

    International Nuclear Information System (INIS)

    Lee, J. Y.; Choi, C. S.; Jee, K. K.; Shin, M. C.; Jang, W. Y.

    1998-01-01

    The objective of this study is to investigate the effect of microstructure and pre-strain on Shape Memory Effect(SME) and transformation behavior in an Fe-32Mn-6.5Si alloy. The alloy was annealed at various temperatures from 600 to 1200 .deg. C for 1 hour to vary microstructure after cold rolling. Shape memory effect and reverse transformation behavior were examined through bending test and TMA after deforming the alloy with various degree of pre-strain. Austenite grain size increases with an increase in heat treatment temperature, except the specimen heat-treated at 600 .deg. C, which remains unrecrystallized. The specimen heat-treated at 600 .deg. C, retaining cold rolling effect, exhibits the best SME due to a high Md temperature. In the recrystallized specimens, the larger grain size, the better SME. As grain size increases, the reverse transformation range becomes shorter, indicating that reverse transformation takes place with less constraint. The better SME in a large grain size can be attributed to the easiness of the reverse transformation

  19. Influence of glass particle size of resin cements on bonding to glass ceramic: SEM and bond strength evaluation.

    Science.gov (United States)

    Valentini, Fernanda; Moraes, Rafael R; Pereira-Cenci, Tatiana; Boscato, Noéli

    2014-05-01

    This study investigated the effect of the filler particle size (micron or submicron) of experimental resin cements on the microtensile bond strength to a glass-ceramic pretreated with hydrofluoric acid (HFA) etching or alumina airborne-particle abrasion (AA). Cements were obtained from a Bis-GMA/TEGDMA mixture filled with 60 mass% micron-sized (1 ± 0.2 µm) or submicron-sized (180 ± 30 µm) Ba-Si-Al glass particles. Ceramic blocks (PM9; VITA) were treated with 10% HFA for 60 s or AA for 15 s. Silane and adhesive were applied. Ceramic blocks were bonded to resin composite blocks (Z250; 3M ESPE) using one of the cements. Bonded specimens were sectioned into beams (n = 20/group) and subjected to microtensile bond strength tests. Data were analyzed using ANOVA and Student-Newman-Keuls' tests (5%). Failure modes were classified under magnification. Morphologies of the treated ceramic surfaces and bonded interfaces were evaluated by scanning electron microscopy. The HFA-submicron group had lower bond strengths than the other groups. All AA-submicron specimens debonded prematurely. Mixed failures were predominant for HFA groups, whereas interfacial failures predominated for AA groups. SEM revealed a honeycomb-like aspect in the HFA-treated ceramic, whereas the AA-treated groups showed an irregular retentive pattern. Continuity of cement infiltration along the bonded interface was more uniform for HFA-treated compared to AA-treated specimens. Cracks toward the bulk of the ceramic were observed in AA-treated specimens. Particle size significantly influenced the ceramic bond strength, whereas surface treatment had a minor effect. Copyright © 2014 Wiley Periodicals, Inc.

  20. New elmisaurine specimens from North America and their relationship to the Mongolian Elmisaurus rarus

    Directory of Open Access Journals (Sweden)

    Gregory F. Funston

    2016-02-01

    Full Text Available New specimens from Canada confirm the presence of elmisaurines in North America and shed light on the relationship of Leptorhynchos elegans to Mongolian forms. These specimens have hindlimb elements previously unknown from elmisaurines in the Dinosaur Park Formation, including tibiae and pedal phalanges. Metatarsal anatomy is sufficiently different to merit a generic distinction from Elmisaurus rarus, and both can be distinguished from Caenagnathus collinsi Sternberg, 1940 and Chirostenotes pergracilis. Differences between these taxa include body size, degree of coossification of the tarsometatarsus, and development of cruciate ridges of the third metatarsal. Histological analysis confirms that these differences are not correlated with ontogenetic age of the specimens. The results support the informal separation of caenagnathids based on metatarsal structure, and allow comments on paleobiological differences between caenagnathids and oviraptorids.

  1. Tensile-Creep Test Specimen Preparation Practices of Surface Support Liners

    Science.gov (United States)

    Guner, Dogukan; Ozturk, Hasan

    2017-12-01

    Ground support has always been considered as a challenging issue in all underground operations. Many forms of support systems and supporting techniques are available in the mining/tunnelling industry. In the last two decades, a new polymer based material, Thin Spray-on Liner (TSL), has attained a place in the market as an alternative to the current areal ground support systems. Although TSL provides numerous merits and has different application purposes, the knowledge on mechanical properties and performance of this material is still limited. In laboratory studies, since tensile rupture is the most commonly observed failure mechanism in field applications, researchers have generally studied the tensile testing of TSLs with modification of American Society for Testing and Materials (ASTM) D-638 standards. For tensile creep testing, specimen preparation process also follows the ASTM standards. Two different specimen dimension types (Type I, Type IV) are widely preferred in TSL tensile testing that conform to the related standards. Moreover, molding and die cutting are commonly used specimen preparation techniques. In literature, there is a great variability of test results due to the difference in specimen preparation techniques and practices. In this study, a ductile TSL product was tested in order to investigate the effect of both specimen preparation techniques and specimen dimensions under 7-day curing time. As a result, ultimate tensile strength, tensile yield strength, tensile modulus, and elongation at break values were obtained for 4 different test series. It is concluded that Type IV specimens have higher strength values compared to Type I specimens and moulded specimens have lower results than that of prepared by using die cutter. Moreover, specimens prepared by molding techniques have scattered test results. Type IV specimens prepared by die cutter technique are suggested for preparation of tensile test and Type I specimens prepared by die cutter technique

  2. Effect of microscopic structure on deformation in nano-sized copper and Cu/Si interfacial cracking

    Energy Technology Data Exchange (ETDEWEB)

    Sumigawa, Takashi, E-mail: sumigawa@cyber.kues.kyoto-u.ac.jp; Nakano, Takuya; Kitamura, Takayuki

    2013-03-01

    The purpose of this work is to examine the effect of microscopic structure on the mechanical properties of nano-sized components (nano-components). We developed a bending specimen with a substructure that can be observed by means of a transmission electron microscope (TEM). We examined the plastic behavior of a Cu bi-crystal and the Cu/Si interfacial cracking in a nano-component. TEM images indicated that an initial plastic deformation takes place near the interface edge (the junction between the Cu/Si interface and the surface) in the Cu film with a high critical resolved shear stress (400–420 MPa). The deformation developed preferentially in a single grain. Interfacial cracking took place at the intersection between the grain boundary and the Cu/Si interface, where a high stress concentration existed due to deformation mismatch. These results indicate that the characteristic mechanical behavior of a nano-component is governed by the microscopic stress field, which takes into account the crystallographic structure. - Highlights: ► A nano-component specimen including a bi-crystal copper layer was prepared. ► A loading test with in-situ transmission electron microscopy was conducted. ► The plastic and cracking behaviors were governed by microscopic stress. ► Stress defined under continuum assumption was still present in nano-components.

  3. Janka hardness using nonstandard specimens

    Science.gov (United States)

    David W. Green; Marshall Begel; William Nelson

    2006-01-01

    Janka hardness determined on 1.5- by 3.5-in. specimens (2×4s) was found to be equivalent to that determined using the 2- by 2-in. specimen specified in ASTM D 143. Data are presented on the relationship between Janka hardness and the strength of clear wood. Analysis of historical data determined using standard specimens indicated no difference between side hardness...

  4. Measurement of deformation field in CT specimen using laser speckle

    International Nuclear Information System (INIS)

    Jeon, Moon Chang; Kang, Ki Ju

    2001-01-01

    To obtain A 2 experimentally in the J-A 2 theory, deformation field on the lateral surface of a CT specimen was to be determined using laser speckle method. The crack growth was measured using direct current potential drop method and most procedure of experimental and data reduction was performed according to ASTM Standard E1737-96. Laser speckle images during crack propagation were monitored by two CCD cameras to cancel the effect of rotation and translation of the specimen. An algorithm to pursue displacement of a point from each image was developed and successfully used to measure A 2 continuously as the crack tip was propagated. The effects of specimen thickness on J-R curve and A 2 were explored

  5. Demonstration of Laser Cutting System for Tube Specimen

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Y. G.; Kim, G. S.; Heo, G. S.; Baik, S. J.; Kim, H. M.; Ahn, S. B. [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    The oxide layer removal system was also developed because the oxide layer on the surface of the irradiated fuel cladding and components interrupted the applying the electric current during the processing. However, it was found that the mechanical testing data of the irradiated specimens with removal of oxide layer was less reliable than the specimens with oxide layer . The laser cutting system using Nd:YAG with fiber optic beam delivery has great potential in material processing applications of the irradiated fuel cladding and components due to non-contact process. Thus, the oxide layer doesn't interrupt the fabrication process during the laser cutting system. In the present study, the laser cutting system was designed to fabricate the mechanical testing specimens from the unirradiated fuel cladding with and without oxide. The feasibility of the laser cutting system was demonstrated for the fabrication of various types of unirradiated specimens. The effect of surface oxide layer was also investigated for machining process of the zirlo fuel cladding and it was found that laser beam machining could be a useful tool to fabricate the specimens with surface oxide layer. Based on the feasibility studies and demonstration, the design of the laser cutting machine for fully or partially automatic and remotely operable system will be proposed and made.

  6. Effect of laser power and specimen temperature on atom probe analyses of magnesium alloys

    International Nuclear Information System (INIS)

    Oh-ishi, K.; Mendis, C.L.; Ohkubo, T.; Hono, K.

    2011-01-01

    The influence of laser power, wave length, and specimen temperature on laser assisted atom probe analyses for Mg alloys was investigated. Higher laser power and lower specimen temperature led to improved mass and spatial resolutions. Background noise and mass resolutions were degraded with lower laser power and higher specimen temperature. By adjusting the conditions for laser assisted atom probe analyses, atom probe results with atomic layer resolutions were obtained from all the Mg alloys so far investigated. Laser assisted atom probe investigations revealed detailed chemical information on Guinier-Preston zones in Mg alloys. -- Research highlights: → We study performance of UV laser assisted atom probe analysis for Mg alloys. → There is an optimized range of laser power and specimen temperature. → Optimized UV laser enables atom probe data of Mg alloys with high special resolution.

  7. Effects of grain size on high temperature creep of fine grained, solution and dispersion hardened V-1.6Y-8W-0.8TiC

    Energy Technology Data Exchange (ETDEWEB)

    Furuno, T. [Ehime Univerisity, 3 Bunkyo-cho, Matsuyama 790-8577 (Japan); Kurishita, H., E-mail: kurishi@imr.tohoku.ac.jp [International Research Center for Nuclear Materials Science, Institute for Materials Research (IMR), Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Nagasaka, T.; Nishimura, A.; Muroga, T. [Fusion Engineering Research Center, National Institute for Fusion Science (NIFS), Oroshi-cho 322-6, Tok, Gifu 292 (Japan); Sakamoto, T.; Kobayashi, S.; Nakai, K. [Department of Materials Science and Biotechnology, Ehime Univerisity, 3 Bunkyo-cho, Matsuyama 790-8577 (Japan); Matsuo, S.; Arakawa, H. [International Research Center for Nuclear Materials Science, Institute for Materials Research (IMR), Tohoku University, Oarai, Ibaraki 311-1313 (Japan)

    2011-10-01

    Creep resistance is the major concern of vanadium and its alloys for fusion reactor structural applications. In order to elucidate the effects of grain size on the creep behavior of solution and dispersion strengthened vanadium alloys, V-1.6Y-8W-0.8TiC specimens with fine grain sizes from 0.58 to 1.45 {mu}m were prepared by mechanical alloying and HIP without any plastic working and tested at 1073 K and 250 MPa in vacuum. It is shown that the creep resistance of V-1.6Y-8W-0.8TiC depends strongly on grain size and increases with increasing grain size: The creep life for the grain size of 1.45 {mu}m is almost one order longer than that of 0.58 {mu}m, and about two orders longer than that of V-4Cr-4Ti (NIFS-Heat 2) although the grain size of V-4Cr-4Ti is as large as 17.8 {mu}m. The observed creep behavior is discussed in terms of grain size effects on dislocation glide and grain boundary sliding.

  8. Causality in Statistical Power: Isomorphic Properties of Measurement, Research Design, Effect Size, and Sample Size

    Directory of Open Access Journals (Sweden)

    R. Eric Heidel

    2016-01-01

    Full Text Available Statistical power is the ability to detect a significant effect, given that the effect actually exists in a population. Like most statistical concepts, statistical power tends to induce cognitive dissonance in hepatology researchers. However, planning for statistical power by an a priori sample size calculation is of paramount importance when designing a research study. There are five specific empirical components that make up an a priori sample size calculation: the scale of measurement of the outcome, the research design, the magnitude of the effect size, the variance of the effect size, and the sample size. A framework grounded in the phenomenon of isomorphism, or interdependencies amongst different constructs with similar forms, will be presented to understand the isomorphic effects of decisions made on each of the five aforementioned components of statistical power.

  9. LPTR irradiation of LLL vanadium tensile specimens and LLL Nb--1Zr tensile specimens

    International Nuclear Information System (INIS)

    MacLean, S.C.; Rowe, C.L.

    1977-01-01

    The LPTR irradiation of 14 LLL vanadium tensile specimens and 14 LLL Nb-1Zr tensile specimens is described. Sample packaging, the irradiation schedule and neutron fluences for three energy ranges are given

  10. Spatial and temporal variation of body size among early Homo.

    Science.gov (United States)

    Will, Manuel; Stock, Jay T

    2015-05-01

    The estimation of body size among the earliest members of the genus Homo (2.4-1.5Myr [millions of years ago]) is central to interpretations of their biology. It is widely accepted that Homo ergaster possessed increased body size compared with Homo habilis and Homo rudolfensis, and that this may have been a factor involved with the dispersal of Homo out of Africa. The study of taxonomic differences in body size, however, is problematic. Postcranial remains are rarely associated with craniodental fossils, and taxonomic attributions frequently rest upon the size of skeletal elements. Previous body size estimates have been based upon well-preserved specimens with a more reliable species assessment. Since these samples are small (n Koobi Fora after 1.7Myr, indicating regional size variation. The significant body size differences between specimens from Koobi Fora and Olduvai support the cranial evidence for at least two co-existing morphotypes in the Early Pleistocene of eastern Africa. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Georeferencing Animal Specimen Datasets

    NARCIS (Netherlands)

    van Erp, M.G.J.; Hensel, R.; Ceolin, D.; van der Meij, M.

    2014-01-01

    For biodiversity research, the field of study that is concerned with the richness of species of our planet, it is of the utmost importance that the location of an animal specimen find is known with high precision. Due to specimens often having been collected over the course of many years, their

  12. Strip specimen tests for pipeline materials and girth welds

    Energy Technology Data Exchange (ETDEWEB)

    Mohr, William C. [Edison Welding Institute (EWI), Columbus, Ohio (United States)

    2009-07-01

    Strip specimen testing of pipeline materials has been widely applied as a method of getting data relevant to the performance of pipelines under axial direction loading. Comparisons of strip specimen against smaller standard tests (round tensile bar, fracture toughness specimens, polished round bars) and against full-scale or large-scale testing will be explored. Data from early-generation pipe welds from the 1920's to the 1940's to the most recent materials for offshore reeled pipe will be used for examples. Strip samples can provide full thickness information to take account of varying material properties or imperfection distribution through the thickness. Strip samples can also accommodate measurement of effects of the original surface finish or weld surface shape. Strip samples have more design flexibility than standard tests, but must be designed to limit stress concentrations and effects of local bending. (author)

  13. Size-scaling of tensile failure stress in boron carbide

    Energy Technology Data Exchange (ETDEWEB)

    Wereszczak, Andrew A [ORNL; Kirkland, Timothy Philip [ORNL; Strong, Kevin T [ORNL; Jadaan, Osama M. [University of Wisconsin, Platteville; Thompson, G. A. [U.S. Army Dental and Trauma Research Detachment, Greak Lakes

    2010-01-01

    Weibull strength-size-scaling in a rotary-ground, hot-pressed boron carbide is described when strength test coupons sampled effective areas from the very small (~ 0.001 square millimeters) to the very large (~ 40,000 square millimeters). Equibiaxial flexure and Hertzian testing were used for the strength testing. Characteristic strengths for several different specimen geometries are analyzed as a function of effective area. Characteristic strength was found to substantially increase with decreased effective area, and exhibited a bilinear relationship. Machining damage limited strength as measured with equibiaxial flexure testing for effective areas greater than ~ 1 mm2 and microstructural-scale flaws limited strength for effective areas less than 0.1 mm2 for the Hertzian testing. The selections of a ceramic strength to account for ballistically-induced tile deflection and to account for expanding cavity modeling are considered in context with the measured strength-size-scaling.

  14. How to Estimate and Interpret Various Effect Sizes

    Science.gov (United States)

    Vacha-Haase, Tammi; Thompson, Bruce

    2004-01-01

    The present article presents a tutorial on how to estimate and interpret various effect sizes. The 5th edition of the Publication Manual of the American Psychological Association (2001) described the failure to report effect sizes as a "defect" (p. 5), and 23 journals have published author guidelines requiring effect size reporting. Although…

  15. In situ TEM and synchrotron characterization of U–10Mo thin specimen annealed at the fast reactor temperature regime

    International Nuclear Information System (INIS)

    Yun, Di; Mo, Kun; Mohamed, Walid; Ye, Bei; Kirk, Marquis A.; Baldo, Peter; Xu, Ruqing; Yacout, Abdellatif M.

    2015-01-01

    U–Mo metallic alloys have been extensively used for the Reduced Enrichment for Research and Test Reactors (RERTR) program, which is now known as the Office of Material Management and Minimization under the Conversion Program. This fuel form has also recently been proposed as fast reactor metallic fuels in the recent DOE Ultra-high Burnup Fast Reactor project. In order to better understand the behavior of U–10Mo fuels within the fast reactor temperature regime, a series of annealing and characterization experiments have been performed. Annealing experiments were performed in situ at the Intermediate Voltage Electron Microscope (IVEM-Tandem) facility at Argonne National Laboratory (ANL). An electro-polished U–10Mo alloy fuel specimen was annealed in situ up to 700 °C. At an elevated temperature of about 540 °C, the U–10Mo specimen underwent a relatively slow microstructure transition. Nano-sized grains were observed to emerge near the surface. At the end temperature of 700 °C, the near-surface microstructure had evolved to a nano-crystalline state. In order to clarify the nature of the observed microstructure, Laue diffraction and powder diffraction experiments were carried out at beam line 34-ID of the Advanced Photon Source (APS) at ANL. Phases present in the as-annealed specimen were identified with both Laue diffraction and powder diffraction techniques. The U–10Mo was found to recrystallize due to thermally-induced recrystallization driven by a high density of pre-existing dislocations. A separate in situ annealing experiment was carried out with a Focused Ion Beam processed (FIB) specimen. A similar microstructure transition occurred at a lower temperature of about 460 °C with a much faster transition rate compared to the electro-polished specimen. - Highlights: • TEM annealing experiments were performed in situ at the IVEM facility up to fast reactor temperature. • At 540 °C, the U-10Mo specimen underwent a slow microstructure transition

  16. In situ TEM and synchrotron characterization of U–10Mo thin specimen annealed at the fast reactor temperature regime

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Di, E-mail: diyun1979@xjtu.edu.cn [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Xi' an Jiao Tong University, 28 Xian Ning West Road, Xi' an 710049 (China); Mo, Kun; Mohamed, Walid; Ye, Bei; Kirk, Marquis A.; Baldo, Peter; Xu, Ruqing; Yacout, Abdellatif M. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

    2015-12-15

    U–Mo metallic alloys have been extensively used for the Reduced Enrichment for Research and Test Reactors (RERTR) program, which is now known as the Office of Material Management and Minimization under the Conversion Program. This fuel form has also recently been proposed as fast reactor metallic fuels in the recent DOE Ultra-high Burnup Fast Reactor project. In order to better understand the behavior of U–10Mo fuels within the fast reactor temperature regime, a series of annealing and characterization experiments have been performed. Annealing experiments were performed in situ at the Intermediate Voltage Electron Microscope (IVEM-Tandem) facility at Argonne National Laboratory (ANL). An electro-polished U–10Mo alloy fuel specimen was annealed in situ up to 700 °C. At an elevated temperature of about 540 °C, the U–10Mo specimen underwent a relatively slow microstructure transition. Nano-sized grains were observed to emerge near the surface. At the end temperature of 700 °C, the near-surface microstructure had evolved to a nano-crystalline state. In order to clarify the nature of the observed microstructure, Laue diffraction and powder diffraction experiments were carried out at beam line 34-ID of the Advanced Photon Source (APS) at ANL. Phases present in the as-annealed specimen were identified with both Laue diffraction and powder diffraction techniques. The U–10Mo was found to recrystallize due to thermally-induced recrystallization driven by a high density of pre-existing dislocations. A separate in situ annealing experiment was carried out with a Focused Ion Beam processed (FIB) specimen. A similar microstructure transition occurred at a lower temperature of about 460 °C with a much faster transition rate compared to the electro-polished specimen. - Highlights: • TEM annealing experiments were performed in situ at the IVEM facility up to fast reactor temperature. • At 540 °C, the U-10Mo specimen underwent a slow microstructure transition

  17. DNA extraction from herbarium specimens.

    Science.gov (United States)

    Drábková, Lenka Záveská

    2014-01-01

    With the expansion of molecular techniques, the historical collections have become widely used. Studying plant DNA using modern molecular techniques such as DNA sequencing plays an important role in understanding evolutionary relationships, identification through DNA barcoding, conservation status, and many other aspects of plant biology. Enormous herbarium collections are an important source of material especially for specimens from areas difficult to access or from taxa that are now extinct. The ability to utilize these specimens greatly enhances the research. However, the process of extracting DNA from herbarium specimens is often fraught with difficulty related to such variables as plant chemistry, drying method of the specimen, and chemical treatment of the specimen. Although many methods have been developed for extraction of DNA from herbarium specimens, the most frequently used are modified CTAB and DNeasy Plant Mini Kit protocols. Nine selected protocols in this chapter have been successfully used for high-quality DNA extraction from different kinds of plant herbarium tissues. These methods differ primarily with respect to their requirements for input material (from algae to vascular plants), type of the plant tissue (leaves with incrustations, sclerenchyma strands, mucilaginous tissues, needles, seeds), and further possible applications (PCR-based methods or microsatellites, AFLP).

  18. Action Mechanism of Iridoid Compounds on Guinea-pig Right Atrium Specimens

    OpenAIRE

    齊藤, 久美子; 酒井 淳一; 堀田 芳弘

    2016-01-01

     We examined the actions of iridoid compounds (aucubin (Auc), geniposidic acid (GA)) and a noniridoid compound (chlorogenic acid (CA)) contained in Eucommia leaves [1] [2], which show blood pressure-lowering effects, on the heart using right atrial specimens isolated from guinea pigs. These 3 compounds showed negative inotropic effects (NIE) and negative chronotropic effects (NCE) at a final concentration of 10 -5 or 10 -4 M in an experiment using right atrial specimens. Furthermore, pretreat...

  19. Innovations in macroscopic evaluation of pancreatic specimens and radiologic correlation

    International Nuclear Information System (INIS)

    Triantopoulou, Charikleia; Papaparaskeva, Kleo; Agalianos, Christos; Dervenis, Christos

    2016-01-01

    •The axial slicing technique offers many advantages in accurate estimation of tumors extend and staging.•Cross-sectional axial imaging is the best technique for accurate radiologic-pathologic correlation.•Correlation may explain any discrepancies between radiological and histopathological findings.•Pathology correlation may offer a better understanding of the missed findings by imaging or pitfalls The axial slicing technique offers many advantages in accurate estimation of tumors extend and staging. Cross-sectional axial imaging is the best technique for accurate radiologic-pathologic correlation. Correlation may explain any discrepancies between radiological and histopathological findings. Pathology correlation may offer a better understanding of the missed findings by imaging or pitfalls The purpose of this study was to evaluate the feasibility of a novel dissection technique of surgical specimens in different cases of pancreatic tumors and provide a radiologic pathologic correlation. In our hospital, that is a referral center for pancreatic diseases, the macroscopic evaluation of the pancreatectomy specimens is performed by the pathologists using the axial slicing technique (instead of the traditional procedure with longitudinal opening of the main pancreatic and/or common bile duct and slicing along the plane defined by both ducts). The specimen is sliced in an axial plane that is perpendicular to the longitudinal axis of the descending duodenum. The procedure results in a large number of thin slices (3–4 mm). This plane is identical to that of CT or MRI and correlation between pathology and imaging is straightforward. We studied 70 cases of suspected different solid and cystic pancreatic tumors and we correlated the tumor size and location, the structure—consistency (areas of necrosis—hemorrhage—fibrosis—inflammation), the degree of vessels’ infiltration, the size of pancreatic and common bile duct and the distance from resection margins

  20. Effect of a shear modified Gurson model on damage development in a FSW tensile specimen

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau; Tvergaard, Viggo

    2009-01-01

    For a friction stir welded aluminum plate the resistance to ductile failure is studied by analyzing tensile test specimens cut out across the weldline. As the stress triaxiality is rather low in these tests, the Gurson material model is not expected to give a very accurate description of the void......, such that the damage parameter does not really represent the void volume fraction. Various amounts of the additional damage evolution are compared with predictions of the original Gurson model. The analyses are carried out for different yield stress profiles transverse to the weld and for different specimen widths....... It is found that the modification does provide additional damage development in the friction stir weld, which may help to fit experimental data. But the suggested modification depends strongly on the overall stress state, and may have a too strong effect in some cases where the stress triaxiality is rather...

  1. AGC-2 Specimen Post Irradiation Data Package Report

    Energy Technology Data Exchange (ETDEWEB)

    Windes, William Enoch [Idaho National Lab. (INL), Idaho Falls, ID (United States); Swank, W. David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rohrbaugh, David T. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cottle, David L. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-08-01

    This report documents results of the post-irradiation examination material property testing of the creep, control, and piggyback specimens from the irradiation creep capsule Advanced Graphite Creep (AGC)-2 are reported. This is the second of a series of six irradiation test trains planned as part of the AGC experiment to fully characterize the neutron irradiation effects and radiation creep behavior of current nuclear graphite grades. The AGC-2 capsule was irradiated in the Idaho National Laboratory Advanced Test Reactor at a nominal temperature of 600°C and to a peak dose of 5 dpa (displacements per atom). One-half of the creep specimens were subjected to mechanical stresses (an applied stress of either 13.8, 17.2, or 20.7 MPa) to induce irradiation creep. All post-irradiation testing and measurement results are reported with the exception of the irradiation mechanical strength testing, which is the last destructive testing stage of the irradiation testing program. Material property tests were conducted on specimens from 15 nuclear graphite grades using a similar loading configuration as the first AGC capsule (AGC-1) to provide easy comparison between the two capsules. However, AGC-2 contained an increased number of specimens (i.e., 487 total specimens irradiated) and replaced specimens of the minor grade 2020 with the newer grade 2114. The data reported include specimen dimensions for both stressed and unstressed specimens to establish the irradiation creep rates, mass and volume data necessary to derive density, elastic constants (Young’s modulus, shear modulus, and Poisson’s ratio) from ultrasonic time-of-flight velocity measurements, Young’s modulus from the fundamental frequency of vibration, electrical resistivity, and thermal diffusivity and thermal expansion data from 100–500°C. No data outliers were determined after all measurements were completed. A brief statistical analysis was performed on the irradiated data and a limited comparison between

  2. Use of the strength ratio for pre-cracked Charpy specimens for the measuring, of the dynamic toughness of steels

    International Nuclear Information System (INIS)

    Pereira, L.C.; Darwish, F.A.I.

    1981-01-01

    The specimen strength ratio (R sub(sb)) determined for precraked Charpy specimens fractured in dynamic bending was correlated with plane strain fracture toughness (K sub(Id)) obtained through valid measurements of the J-integral at the moment of fracture initiation in various microstructures of the AISI 4140 steel. The results indicate a linear relationship between K sub(Id) and R sub(sb) for the microstructures considered in this work. The range of validity of this linear correlation is presented and discussed in terms of the ASTM E399 specimen size criterion. (Author) [pt

  3. Biofuel manufacturing from woody biomass: effects of sieve size used in biomass size reduction.

    Science.gov (United States)

    Zhang, Meng; Song, Xiaoxu; Deines, T W; Pei, Z J; Wang, Donghai

    2012-01-01

    Size reduction is the first step for manufacturing biofuels from woody biomass. It is usually performed using milling machines and the particle size is controlled by the size of the sieve installed on a milling machine. There are reported studies about the effects of sieve size on energy consumption in milling of woody biomass. These studies show that energy consumption increased dramatically as sieve size became smaller. However, in these studies, the sugar yield (proportional to biofuel yield) in hydrolysis of the milled woody biomass was not measured. The lack of comprehensive studies about the effects of sieve size on energy consumption in biomass milling and sugar yield in hydrolysis process makes it difficult to decide which sieve size should be selected in order to minimize the energy consumption in size reduction and maximize the sugar yield in hydrolysis. The purpose of this paper is to fill this gap in the literature. In this paper, knife milling of poplar wood was conducted using sieves of three sizes (1, 2, and 4 mm). Results show that, as sieve size increased, energy consumption in knife milling decreased and sugar yield in hydrolysis increased in the tested range of particle sizes.

  4. Electrokinetic Flow in Microchannels with Finite Reservoir Size Effects

    International Nuclear Information System (INIS)

    Yan, D; Yang, C; Nguyen, N-T; Huang, X

    2006-01-01

    In electrokinetically-driven microfluidic applications, reservoirs are indispensable and have finite sizes. During operation processes, as the liquid level difference in reservoirs keeps changing as time elapses, the flow characteristics in a microchannel exhibit a combination of the electroosmotic flow and the time-dependent induced backpressure-driven flow. In this work, an assessment of the finite reservoir size effect on electroosmotic flows is presented theoretically and experimentally. A model is developed to describe the timedependent electrokinetic flow with finite reservoir size effects. The theoretical analysis shows that under certain conditions the finite reservoir size effect is significant. The important parameters that describe the effect of finite reservoir size on the flow characteristics are discussed. A new concept denoted as 'effective pumping period' is introduced to characterize the reservoir size effect. The proposed model clearly identifies the mechanisms of the finitereservoir size effects and is further confirmed by using micro-PIV technique. The results of this study can be used for facilitating the design of microfluidic devices

  5. Influence of Nb content on grain size and mechanical properties of 18 wt% Cr ferritic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Y. [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Mao, W.M., E-mail: weiminmao@263.net [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Chen, Y.J. [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Jing, J.; Cheng, M. [Taizhou Xinyu Precision Manufacture Company Limited, Jiangyan 225500, Jiangsu (China)

    2016-11-20

    The influence of Nb contents between 0.20 and 1.20 wt% on the grain size and mechanical properties of 18 wt% Cr ferritic stainless steel produced by investment casting was investigated. The average grain sizes of the three steels decreased apparently with increasing Nb content mainly due to the increasing number of pre-existing oxides formed at higher temperature, which were more likely to be the nuclei of heterogeneous nucleation. The thermodynamic analysis of Nb(C,N) formation was in conformity to the experimental result that the Nb(C,N) precipitates became larger with increasing Nb content. The as-cast specimen with the smallest grain size of steel C had the worse tensile strength and elongation in comparison with the as-cast specimens of steels A and B, mostly owing to the catenarian and dendritic Nb(C,N) particles distributed densely at the grain boundaries. The mechanical properties of specimens were not improved remarkably through high temperature solid-solution, whereas the mechanical properties of normalized specimens in the three steels were improved to different degrees. The coalescence and sparse distribution of smaller precipitates at grain boundaries after normalizing effectively weakened the local stress concentration arising from the reticular distribution of particles. The normalized specimen of steel A with 0.24 wt% Nb still showed good mechanical properties. Normalizing at 850 °C for 2 h is the appropriate heat treatment for the 18 wt% Cr ferritic stainless steel. The comparatively rational Nb content of the ferritic stainless steel is between 0.20 and 0.40 wt% for investment casting production.

  6. Statistical properties of four effect-size measures for mediation models.

    Science.gov (United States)

    Miočević, Milica; O'Rourke, Holly P; MacKinnon, David P; Brown, Hendricks C

    2018-02-01

    This project examined the performance of classical and Bayesian estimators of four effect size measures for the indirect effect in a single-mediator model and a two-mediator model. Compared to the proportion and ratio mediation effect sizes, standardized mediation effect-size measures were relatively unbiased and efficient in the single-mediator model and the two-mediator model. Percentile and bias-corrected bootstrap interval estimates of ab/s Y , and ab(s X )/s Y in the single-mediator model outperformed interval estimates of the proportion and ratio effect sizes in terms of power, Type I error rate, coverage, imbalance, and interval width. For the two-mediator model, standardized effect-size measures were superior to the proportion and ratio effect-size measures. Furthermore, it was found that Bayesian point and interval summaries of posterior distributions of standardized effect-size measures reduced excessive relative bias for certain parameter combinations. The standardized effect-size measures are the best effect-size measures for quantifying mediated effects.

  7. Estimating the average grain size of metals - approved standard 1969

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    These methods cover procedures for estimating and rules for expressing the average grain size of all metals and consisting entirely, or principally, of a single phase. The methods may also be used for any structures having appearances similar to those of the metallic structures shown in the comparison charts. The three basic procedures for grain size estimation which are discussed are comparison procedure, intercept (or Heyn) procedure, and planimetric (or Jeffries) procedure. For specimens consisting of equiaxed grains, the method of comparing the specimen with a standard chart is most convenient and is sufficiently accurate for most commercial purposes. For high degrees of accuracy in estimating grain size, the intercept or planimetric procedures may be used

  8. Feasibility Study of Laser Cutting for Fabrication of Tensile Specimen

    International Nuclear Information System (INIS)

    Jin, Y. G.; Baik, S. J.; Kim, G. S.; Heo, G. S.; Yoo, B. O.; Ahn, S. B.; Chun, Y. B.

    2015-01-01

    The specimen fabrication technique was established to machine the specimen from the irradiated materials. The wire cut EDM(electric discharge machine) was modified to fabricate the mechanical testing specimens from irradiated components and fuel claddings. The oxide layer removal system was also developed because the oxide layer on the surface of the irradiated components and claddings interrupted the applying the electric current during the processing. However, zirconium oxide is protective against further corrosion as well as beneficial to mechanical strength for the tensile deformation of the cladding. Thus, it is important to fabricate the irradiated specimens without removal of oxide layer on the surface of the irradiated structural components and claddings. In the present study, laser cutting system was introduced to fabricate the various mechanical testing specimens from the unirradiated fuel cladding and the feasibility of the laser cutting system was studied for the fabrication of various types of irradiated specimens in a hot cell at IMEF (Irradiated Materials Examination Facility) of KAERI. Laser beam machining system was introduced to fabricate the various mechanical testing specimens from the unirradiated fuel cladding and the dimensions were compared for the feasibility of the laser cutting system. The effect of surface oxide layer was also investigated for machining process of the zircaloy-4 fuel cladding and it was found that laser beam machining could be a useful tool to fabricate the specimens with surface oxide layer

  9. Feasibility Study of Laser Cutting for Fabrication of Tensile Specimen

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Y. G.; Baik, S. J.; Kim, G. S.; Heo, G. S.; Yoo, B. O.; Ahn, S. B.; Chun, Y. B. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The specimen fabrication technique was established to machine the specimen from the irradiated materials. The wire cut EDM(electric discharge machine) was modified to fabricate the mechanical testing specimens from irradiated components and fuel claddings. The oxide layer removal system was also developed because the oxide layer on the surface of the irradiated components and claddings interrupted the applying the electric current during the processing. However, zirconium oxide is protective against further corrosion as well as beneficial to mechanical strength for the tensile deformation of the cladding. Thus, it is important to fabricate the irradiated specimens without removal of oxide layer on the surface of the irradiated structural components and claddings. In the present study, laser cutting system was introduced to fabricate the various mechanical testing specimens from the unirradiated fuel cladding and the feasibility of the laser cutting system was studied for the fabrication of various types of irradiated specimens in a hot cell at IMEF (Irradiated Materials Examination Facility) of KAERI. Laser beam machining system was introduced to fabricate the various mechanical testing specimens from the unirradiated fuel cladding and the dimensions were compared for the feasibility of the laser cutting system. The effect of surface oxide layer was also investigated for machining process of the zircaloy-4 fuel cladding and it was found that laser beam machining could be a useful tool to fabricate the specimens with surface oxide layer.

  10. A 3D dislocation dynamics analysis of the size effect on the strength of [1 1 1] LiF micropillars at 300K and 600K

    International Nuclear Information System (INIS)

    Chang, Hyung-Jun; Segurado, Javier; Molina-Aldareguía, Jon M; Soler, Rafael

    2016-01-01

    The mechanical behavior in compression of [1 1 1] LiF micropillars with diameters in the range 0.5 μm to 2.0 μm was analyzed by means of discrete dislocation dynamics at ambient and elevated temperature. The dislocation velocity was obtained from the Peach–Koehler force acting on the dislocation segments from a thermally-activated model that accounted for the influence of temperature on the lattice resistance. A size effect of the type ‘smaller is stronger’ was predicted by the simulations, which was in quantitative agreement with previous experimental results by the authors [1]. The contribution of the different physical deformation mechanisms to the size effect (namely, nucleation of dislocations, dislocation exhaustion and forest hardening) could be ascertained from the simulations and the dominant deformation mode could be assessed as a function of the specimen size and temperature. These results shed light into the complex interaction among size, lattice resistance and dislocation mobility in the mechanical behavior of μm-sized single crystals. (paper)

  11. Techniques in human airway inflammation - Quantity and morphology of bronchial biopsy specimens taken by forceps of three sizes

    NARCIS (Netherlands)

    Aleva, RM; Kraan, J; Smith, M; ten Hacken, NHT; Postma, DS; Timens, W

    Background: In recent years, fiberoptic bronchoscopy has been introduced successfully in the research of bronchial asthma. Bronchial biopsy specimens obtained by this procedure are small, and an optimal biopsy technique is necessary to obtain high-quality tissue samples, as sufficient length of

  12. Evaluation of A-1 reactor heavy-water calandria specimens

    International Nuclear Information System (INIS)

    Brumovsky, M.

    1976-01-01

    Container chains with surveillance specimens were placed in two special channels of the core peripheral part to test changes in mechanical properties due to reactor operation of caisson tube material. The specimens were made from the caisson tube material and placed by eight pieces on the outer surface of the containers. The first removed specimens were tested for corrosion losses, tensile strength, and fractured surfaces were then assessed. The changes in strength properties were found to be similar in both base material and welded joints. The corrosion film on surveillance specimens did not practically affect strength properties nor ductility. It was found that the Al-Mg-Si alloy used for the heavy water vessel caisson tubes following stabilization annealing was fully stable at operating temperatures of up to 100 degC. Slio.ht changes in properties can be attributed to the effect of a high neutron dose. Thus, the high radiation and temperature stability of the alloy was confirmed. (O.K.)

  13. Strain Amount Dependent Grain Size and Orientation Developments during Hot Compression of a Polycrystalline Nickel Based Superalloy

    Directory of Open Access Journals (Sweden)

    Guoai He

    2017-02-01

    Full Text Available Controlling grain size in polycrystalline nickel base superalloy is vital for obtaining required mechanical properties. Typically, a uniform and fine grain size is required throughout forging process to realize the superplastic deformation. Strain amount occupied a dominant position in manipulating the dynamic recrystallization (DRX process and regulating the grain size of the alloy during hot forging. In this article, the high-throughput double cone specimen was introduced to yield wide-range strain in a single sample. Continuous variations of effective strain ranging from 0.23 to 1.65 across the whole sample were achieved after reaching a height reduction of 70%. Grain size is measured to be decreased from the edge to the center of specimen with increase of effective strain. Small misorientation tended to generate near the grain boundaries, which was manifested as piled-up dislocation in micromechanics. After the dislocation density reached a critical value, DRX progress would be initiated at higher deformation region, leading to the refinement of grain size. During this process, the transformations from low angle grain boundaries (LAGBs to high angle grain boundaries (HAGBs and from subgrains to DRX grains are found to occur. After the accomplishment of DRX progress, the neonatal grains are presented as having similar orientation inside the grain boundary.

  14. Text Fixture for Double Cantilever Beam (DCB) Specimens Subjected to Uneven Bending Moments

    DEFF Research Database (Denmark)

    Svenninggaard, Jon; Andreasen, Jens; Bak, Brian

    Bending Moments as a function of the phase angle ranging from mode I to mode II loading including mixed modes in-between. The test fixture utilizes an existing tensile testing machine and can subject specimens to loads up to 350 Nm. The test fixture is compact in size and designed using standard aluminium...... profiles for the main structure. The load is transferred from the test machine to the specimen through a 2 mm Dyneema rope. The rope is routed over a set of rollers that are positioned according to the specified mode mixity and phase angle. The kinematics of the test fixture has been analysed extensively...... strength in layered materials the cohesive law and fracture strength must be known. Ideally the entire cohesive law is known in order to aid in the design of components and structures. In this work we present a novel test fixture which can be used to test DCB specimens that are subjected to pure Uneven...

  15. Size effects in crystal plasticity

    DEFF Research Database (Denmark)

    Borg, Ulrik

    2007-01-01

    Numerical analyses of plasticity size effects have been carried out for different problems using a developed strain gradient crystal plasticiy theory. The theory employs higher order stresses as work conjugates to slip gradients and uses higher order boundary conditions. Problems on localization...... of plastic flow in a single crystal, grain boundary effects in a bicrystal, and grain size effects in a polycrystal are studied. Single crystals containing micro-scale voids have also been analyzed at different loading conditions with focus on the stress and deformation fields around the voids, on void...... growth and interaction between neighboring voids, and on a comparison between the developed strain gradient crystal plasticity theory and a discrete dislocation plasticity theory. Furthermore, voids and rigid inclusions in isotropic materials have been studied using a strain gradient plasticity theory...

  16. Quantitative X-ray microanalysis of biological specimens

    International Nuclear Information System (INIS)

    Roomans, G.M.

    1988-01-01

    Qualitative X-ray microanalysis of biological specimens requires an approach that is somewhat different from that used in the materials sciences. The first step is deconvolution and background subtraction on the obtained spectrum. The further treatment depends on the type of specimen: thin, thick, or semithick. For thin sections, the continuum method of quantitation is most often used, but it should be combined with an accurate correction for extraneous background. However, alternative methods to determine local mass should also be considered. In the analysis of biological bulk specimens, the ZAF-correction method appears to be less useful, primarily because of the uneven surface of biological specimens. The peak-to-local background model may be a more adequate method for thick specimens that are not mounted on a thick substrate. Quantitative X-ray microanalysis of biological specimens generally requires the use of standards that preferably should resemble the specimen in chemical and physical properties. Special problems in biological microanalysis include low count rates, specimen instability and mass loss, extraneous contributions to the spectrum, and preparative artifacts affecting quantitation. A relatively recent development in X-ray microanalysis of biological specimens is the quantitative determination of local water content

  17. Interpreting and Reporting Effect Sizes in Research Investigations.

    Science.gov (United States)

    Tapia, Martha; Marsh, George E., II

    Since 1994, the American Psychological Association (APA) has advocated the inclusion of effect size indices in reporting research to elucidate the statistical significance of studies based on sample size. In 2001, the fifth edition of the APA "Publication Manual" stressed the importance of including an index of effect size to clarify…

  18. Permanent magnet finger-size scanning electron microscope columns

    Energy Technology Data Exchange (ETDEWEB)

    Nelliyan, K., E-mail: elenk@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Khursheed, A. [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore)

    2011-07-21

    This paper presents permanent magnet scanning electron microscope (SEM) designs for both tungsten and field emission guns. Each column makes use of permanent magnet technology and operates at a fixed primary beam voltage. A prototype column operating at a beam voltage of 15 kV was made and tested inside the specimen chamber of a conventional SEM. A small electrostatic stigmator unit and dedicated scanning coils were integrated into the column. The scan coils were wound directly around the objective lens iron core in order to reduce its size. Preliminary experimental images of a test grid specimen were obtained through the prototype finger-size column, demonstrating that it is in principle feasible.

  19. Permanent magnet finger-size scanning electron microscope columns

    International Nuclear Information System (INIS)

    Nelliyan, K.; Khursheed, A.

    2011-01-01

    This paper presents permanent magnet scanning electron microscope (SEM) designs for both tungsten and field emission guns. Each column makes use of permanent magnet technology and operates at a fixed primary beam voltage. A prototype column operating at a beam voltage of 15 kV was made and tested inside the specimen chamber of a conventional SEM. A small electrostatic stigmator unit and dedicated scanning coils were integrated into the column. The scan coils were wound directly around the objective lens iron core in order to reduce its size. Preliminary experimental images of a test grid specimen were obtained through the prototype finger-size column, demonstrating that it is in principle feasible.

  20. A new mass mortality of juvenile Protoceratops and size-segregated aggregation behaviour in juvenile non-avian dinosaurs.

    Directory of Open Access Journals (Sweden)

    David W E Hone

    Full Text Available BACKGROUND: Monodominant bonebeds are a relatively common occurrence for non-avian dinosaurs, and have been used to infer associative, and potentially genuinely social, behavior. Previously known assemblages are characterized as either mixed size-classes (juvenile and adult-sized specimens together or single size-classes of individuals (only juveniles or only adult-sized individuals within the assemblage. In the latter case, it is generally unknown if these kinds of size-segregated aggregations characterize only a particular size stage or represent aggregations that happened at all size stages. Ceratopsians ("horned dinosaurs" are known from both types of assemblages. METHODS/PRINCIPAL FINDINGS: Here we describe a new specimen of the ceratopsian dinosaur Protoceratops andrewsi, Granger and Gregory 1923 from Mongolia representing an aggregation of four mid-sized juvenile animals. In conjunction with existing specimens of groups of P. andrewsi that includes size-clustered aggregations of young juveniles and adult-sized specimens, this new material provides evidence for some degree of size-clustered aggregation behaviour in Protoceratops throughout ontogeny. This continuity of size-segregated (and presumably age-clustered aggregation is previously undocumented in non-avian dinosaurs. CONCLUSIONS: The juvenile group fills a key gap in the available information on aggregations in younger ceratopsians. Although we support the general hypothesis that many non-avian dinosaurs were gregarious and even social animals, we caution that evidence for sociality has been overstated and advocate a more conservative interpretation of some data of 'sociality' in dinosaurs.

  1. A new mass mortality of juvenile Protoceratops and size-segregated aggregation behaviour in juvenile non-avian dinosaurs.

    Science.gov (United States)

    Hone, David W E; Farke, Andrew A; Watabe, Mahito; Shigeru, Suzuki; Tsogtbaatar, Khishigjav

    2014-01-01

    Monodominant bonebeds are a relatively common occurrence for non-avian dinosaurs, and have been used to infer associative, and potentially genuinely social, behavior. Previously known assemblages are characterized as either mixed size-classes (juvenile and adult-sized specimens together) or single size-classes of individuals (only juveniles or only adult-sized individuals within the assemblage). In the latter case, it is generally unknown if these kinds of size-segregated aggregations characterize only a particular size stage or represent aggregations that happened at all size stages. Ceratopsians ("horned dinosaurs") are known from both types of assemblages. Here we describe a new specimen of the ceratopsian dinosaur Protoceratops andrewsi, Granger and Gregory 1923 from Mongolia representing an aggregation of four mid-sized juvenile animals. In conjunction with existing specimens of groups of P. andrewsi that includes size-clustered aggregations of young juveniles and adult-sized specimens, this new material provides evidence for some degree of size-clustered aggregation behaviour in Protoceratops throughout ontogeny. This continuity of size-segregated (and presumably age-clustered) aggregation is previously undocumented in non-avian dinosaurs. The juvenile group fills a key gap in the available information on aggregations in younger ceratopsians. Although we support the general hypothesis that many non-avian dinosaurs were gregarious and even social animals, we caution that evidence for sociality has been overstated and advocate a more conservative interpretation of some data of 'sociality' in dinosaurs.

  2. Strain Measurement System Developed for Biaxially Loaded Cruciform Specimens

    Science.gov (United States)

    Krause, David L.

    2000-01-01

    A new extensometer system developed at the NASA Glenn Research Center at Lewis Field measures test area strains along two orthogonal axes in flat cruciform specimens. This system incorporates standard axial contact extensometers to provide a cost-effective high-precision instrument. The device was validated for use by extensive testing of a stainless steel specimen, with specimen temperatures ranging from room temperature to 1100 F. In-plane loading conditions included several static biaxial load ratios, plus cyclic loadings of various waveform shapes, frequencies, magnitudes, and durations. The extensometer system measurements were compared with strain gauge data at room temperature and with calculated strain values for elevated-temperature measurements. All testing was performed in house in Glenn's Benchmark Test Facility in-plane biaxial load frame.

  3. Friction Compensation in the Upsetting of Cylindrical Test Specimens

    DEFF Research Database (Denmark)

    Christiansen, Peter; Martins, P. A. F.; Bay, Niels Oluf

    2016-01-01

    This manuscript presents a combined numerical andexperimental methodology for determining the stress-straincurve of metallic materials from the measurements of forceand displacement obtained in the axial compression of cylindrical test specimens with friction between the specimens and the platens....... The methodology is based on minimizing the errorbetween the average surface pressure obtained from the experimental measurements of the force and displacement and thatobtained from the slab method of analysis of metal plasticity.Three different friction models based on Coulomb friction, the constant friction...... model or combined friction models are utilized .Experimental results obtained from cylindrical and Rastegaev test specimens with different lubricants combined with the experimental determination of friction by means of ring compression tests allows compensating the effect of friction...

  4. Portion size and intended consumption. Evidence for a pre-consumption portion size effect in males?

    Science.gov (United States)

    Robinson, Eric; te Raa, Wesselien; Hardman, Charlotte A

    2015-08-01

    Larger portions increase energy intake (the 'portion size effect'); however, the mechanisms behind this effect are unclear. Although pre-meal intentions are thought to be an important determinant of energy intake, little research has examined how much of a meal individuals intend to eat when served standard versus larger portion sizes. Three studies examined the effect of manipulating portion size on intended food consumption. In Studies 1 (spaghetti bolognese) and 2 (curry and rice) male participants were shown an image of either a standard or a larger meal and indicated how much of the meal they intended to consume. In Study 3 male and female participants were served either a standard or a larger portion of ice cream for dessert, they indicated how much they intended to consume and then ate as much of the ice cream as they desired. Regardless of being shown standard or large portion sizes, in Studies 1 and 2 participants reported that they intended to eat the majority of the meal, equating to a large difference in intended energy consumption between portion size conditions (a 'pre-consumption portion size effect'). This finding was replicated in male participants in Study 3, although females intended to eat a smaller proportion of the larger portion of ice cream, compared to the standard portion. Both male and female participants tended to eat in accordance with their pre-meal intentions and a portion size effect on actual consumption was subsequently observed in males, but not in females. The portion size effect may be observed when measuring pre-meal intended consumption in males. Copyright © 2015. Published by Elsevier Ltd.

  5. The effect of oxide particles on the strength and ductility of bulk iron with a bimodal grain size distribution

    Energy Technology Data Exchange (ETDEWEB)

    Casas, C.; Tejedor, R. [Department of Materials Science and Metallurgical Engineering, ETSEIB, Universitat Politècnica de Catalunya, Av. Diagonal 647, 08028 Barcelona (Spain); Rodríguez-baracaldo, R. [Department of Mechanical Engineering, Universidad Nacional de Colombia, Bogotá. Colombia (Colombia); Benito, J.A., E-mail: Josep.a.benito@upc.edu [Department of Materials Science and Metallurgical Engineering, EUETIB, Universitat Politècnica de Catalunya, Comte d' Urgell 187, 08036 Barcelona (Spain); Fundació CTM Centre Tecnològic de Manresa, Plaça de la Ciencia, 2, 08243 Manresa (Spain); Cabrera, J.M. [Department of Materials Science and Metallurgical Engineering, ETSEIB, Universitat Politècnica de Catalunya, Av. Diagonal 647, 08028 Barcelona (Spain); Fundació CTM Centre Tecnològic de Manresa, Plaça de la Ciencia, 2, 08243 Manresa (Spain)

    2015-03-11

    The strength and ductility of bulk nanostructured and ultrafine-grained iron containing 0.39% oxygen by weight was determined by tensile tests. Samples were obtained by consolidation of milled iron powder at 500 °C. Heat treatments were designed to cover a wide range of grain sizes spanning from 100 to 2000 nm with different percentages of coarse and nanostructured grain areas, which was defined as a bimodal grain size distribution. Transmission electron microscopy was used to determine the diameter, volume fraction and location of oxides in the microstructure. The strength was analysed following two approaches. The first one was based on the strong effect of oxides and involved the use of a mixed particle-grain boundary strengthening model, and the second one was based on simple grain boundary strengthening. The mixed model underestimated the strength of nanostructured samples, whereas the simple grain boundary model worked better. However, for specimens with a bimodal grain size, the fitting of the mixed model was better. In this case, the more effective particle strengthening was related to the dispersion of oxides inside the large ferrite grains. In addition, the bimodal samples showed an acceptable combination of strength and ductility. Again, the ferrite grains containing oxides promoted strain hardening due to the increase in dislocation activity.

  6. Influence of preservative and mounting media on the size and shape of monogenean sclerites.

    Science.gov (United States)

    Fankoua, Severin-Oscar; Bitja Nyom, Arnold R; Bahanak, Dieu Ne Dort; Bilong Bilong, Charles F; Pariselle, Antoine

    2017-08-01

    Based on Cichlidogyrus sp. (Monogenea, Ancyrocephalidae) specimens from Hemichromis sp. hosts, we tested the influence of different methods to fix/preserve samples/specimens [frozen material, alcohol or formalin preserved, museum process for fish preservation (fixed in formalin and preserved in alcohol)] and different media used to mount the slides [tap water, glycerin ammonium picrate (GAP), Hoyer's one (HM)] on the size/shape of sclerotized parts of monogenean specimens. The results show that the use of HM significantly increases the size of haptoral sclerites [marginal hooks I, II, IV, V, and VI; dorsal bar length, width, distance between auricles and auricle length, ventral bar length and width], and changes their shape [angle opening between shaft and guard (outer and inner roots) in both ventral and dorsal anchors, ventral bar much wider, dorsal one less curved]. This influence seems to be reduced when specimens/samples are fixed in formalin. The systematics of Monogenea being based on the size and shape of their sclerotized parts, to prevent misidentifications or description of invalid new species, we recommend the use of GAP as mounting medium; Hoyer's one should be restricted to monogenean specimens fixed for a long time which are more shrunken.

  7. Controlled Environment Specimen Transfer

    DEFF Research Database (Denmark)

    Damsgaard, Christian Danvad; Zandbergen, Henny W.; Hansen, Thomas Willum

    2014-01-01

    an environmental transmission electron microscope to an in situ X-ray diffractometer through a dedicated transmission electron microscope specimen transfer holder, capable of sealing the specimen in a gaseous environment at elevated temperatures. Two catalyst material systems have been investigated; Cu/ZnO/Al2O3...... transferred in a reactive environment to the environmental transmission electron microscope where further analysis on the local scale were conducted. The Co/Al2O3 catalyst was reduced in the environmental microscope and successfully kept reduced outside the microscope in a reactive environment. The in situ......Specimen transfer under controlled environment conditions, such as temperature, pressure, and gas composition, is necessary to conduct successive complementary in situ characterization of materials sensitive to ambient conditions. The in situ transfer concept is introduced by linking...

  8. Acoustic emission during tensile deformation and fracture of nuclear grade AISI type 304 stainless steel specimens with notches

    International Nuclear Information System (INIS)

    Mukhopadhyay, C.K.; Jayakumar, T.; Baldev Raj

    1996-01-01

    Acoustic emission generated during tensile deformation and fracture of nuclear grade AISI type 304 stainless steel specimens with notches has been studied. The extent of acoustic activity generated depends on notch tip severity, notch tip blunting and tearing of the notches. The equation N=AK m applied to the acoustic emission data of the notched specimens has shown good correlation. Acoustic emission technique can be used to estimate the size of an unknown notch. (author)

  9. 3D printing from microfocus computed tomography (micro-CT) in human specimens: education and future implications.

    Science.gov (United States)

    Shelmerdine, Susan C; Simcock, Ian C; Hutchinson, John Ciaran; Aughwane, Rosalind; Melbourne, Andrew; Nikitichev, Daniil I; Ong, Ju-Ling; Borghi, Alessandro; Cole, Garrard; Kingham, Emilia; Calder, Alistair D; Capelli, Claudio; Akhtar, Aadam; Cook, Andrew C; Schievano, Silvia; David, Anna; Ourselin, Sebastian; Sebire, Neil J; Arthurs, Owen J

    2018-06-14

    Microfocus CT (micro-CT) is an imaging method that provides three-dimensional digital data sets with comparable resolution to light microscopy. Although it has traditionally been used for non-destructive testing in engineering, aerospace industries and in preclinical animal studies, new applications are rapidly becoming available in the clinical setting including post-mortem fetal imaging and pathological specimen analysis. Printing three-dimensional models from imaging data sets for educational purposes is well established in the medical literature, but typically using low resolution (0.7 mm voxel size) data acquired from CT or MR examinations. With higher resolution imaging (voxel sizes below 1 micron, printing of micro-CT imaged specimens can provide insight into craniofacial surgical applications, developmental cardiac anatomy, placental imaging, archaeological remains and high-resolution bone imaging. We conclude with other potential future usages of this emerging technique.

  10. Biaxial Testing of 2195 Aluminum Lithium Alloy Using Cruciform Specimens

    Science.gov (United States)

    Johnston, W. M.; Pollock, W. D.; Dawicke, D. S.; Wagner, John A. (Technical Monitor)

    2002-01-01

    A cruciform biaxial test specimen was used to test the effect of biaxial load on the yield of aluminum-lithium alloy 2195. Fifteen cruciform specimens were tested from 2 thicknesses of 2195-T8 plate, 0.45 in. and 1.75 in. These results were compared to the results from uniaxial tensile tests of the same alloy, and cruciform biaxial tests of aluminum alloy 2219-T87.

  11. Finite size effects of a pion matrix element

    International Nuclear Information System (INIS)

    Guagnelli, M.; Jansen, K.; Palombi, F.; Petronzio, R.; Shindler, A.; Wetzorke, I.

    2004-01-01

    We investigate finite size effects of the pion matrix element of the non-singlet, twist-2 operator corresponding to the average momentum of non-singlet quark densities. Using the quenched approximation, they come out to be surprisingly large when compared to the finite size effects of the pion mass. As a consequence, simulations of corresponding nucleon matrix elements could be affected by finite size effects even stronger which could lead to serious systematic uncertainties in their evaluation

  12. An acceleration test for stress corrosion cracking using humped specimen

    International Nuclear Information System (INIS)

    Kamaya, Masayuki; Fukumura, Takuya; Totsuka, Nobuo

    2003-01-01

    By using the humped specimen, which is processed by the humped die, in the slow strain rate technique (SSRT) test, fracture facet due to stress corrosion cracking (SCC) can be observed in relatively short duration. Although the cold work and concentrated stress and strain caused by the characteristic shape of the specimen accelerate the SCC, to date these acceleration effects have not been examined quantitatively. In the present study, the acceleration effects of the humped specimen were examined through experiments and finite element analyses (FEA). The experiments investigated the SCC of alloy 600 in the primary water environment of a pressurized water reactor. SSRT tests were conducted using two kinds of humped specimen: one was annealed after hump processing in order to eliminate the cold work, and the other was hump processed after the annealing treatment. The work ratio caused by the hump processing and stress/strain conditions during SSRT test were evaluated by FEA. It was found that maximum work ratio of 30% is introduced by the hump processing and that the distribution of the work ratio is not uniform. Furthermore, the work ratio is influenced by the friction between the specimen and dies as well as by the shape of dies. It was revealed that not only the cold work but also the concentrated stress and strain during SSRT test accelerate the crack initiation and growth of the SCC. (author)

  13. Do Class Size Effects Differ across Grades?

    Science.gov (United States)

    Nandrup, Anne Brink

    2016-01-01

    This paper contributes to the class size literature by analysing whether short-run class size effects are constant across grade levels in compulsory school. Results are based on administrative data on all pupils enrolled in Danish public schools. Identification is based on a government-imposed class size cap that creates exogenous variation in…

  14. Evaluation of constraint methodologies applied to a shallow-flaw cruciform bend specimen tested under biaxial loading conditions

    International Nuclear Information System (INIS)

    Bass, B.R.; McAfee, W.J.; Williams, P.T.; Pennell, W.E.

    1998-01-01

    A technology to determine shallow-flaw fracture toughness of reactor pressure vessel (RPV) steels is being developed for application to the safety assessment of RPVs containing postulated shallow surface flaws. Matrices of cruciform beam tests were developed to investigate and quantify the effects of temperature, biaxial loading, and specimen size on fracture initiation toughness of two-dimensional (constant depth), shallow surface flaws. The cruciform beam specimens were developed at Oak Ridge National Laboratory (ORNL) to introduce a prototypic, far-field. out-of-plane biaxial stress component in the test section that approximates the nonlinear stresses resulting from pressurized-thermal-shock or pressure-temperature loading of an RPV. Tests were conducted under biaxial load ratios ranging from uniaxial to equibiaxial. These tests demonstrated that biaxial loading can have a pronounced effect on shallow-flaw fracture toughness in the lower transition temperature region for RPV materials. The cruciform fracture toughness data were used to evaluate fracture methodologies for predicting the observed effects of biaxial loading on shallow-flaw fracture toughness. Initial emphasis was placed on assessment of stress-based methodologies. namely, the J-Q formulation, the Dodds-Anderson toughness scaling model, and the Weibull approach. Applications of these methodologies based on the hydrostatic stress fracture criterion indicated an effect of loading-biaxiality on fracture toughness, the conventional maximum principal stress criterion indicated no effect

  15. The effect of sand/cement ratio on radon exhalation from cement specimens containing 226Ra

    International Nuclear Information System (INIS)

    Takriti, S.; Shweikani, R.; Ali, A. F.; Rajaa, G.

    2002-09-01

    Portland cement was mixed with different kind of sand (calcite and silica) in different ratio to produce radioactive specimens with radium chloride. The release of radon from these samples was studied. The results showed that radon release from the calcite-cement samples increased with the increases of the sand mixed ratio until fixed value (about 20%) then decreased to less than its release from the beginning, and the release changed with the sand size also. Radon release from silica-cement samples had the same observations of calcite-cement samples. It was found that calcite-cement reduced the radon exhalation quantity rather than the silica-cement samples. The decreases of the radon exhalation from the cement-sand may be due to the creation of free spaces in the samples, which gave the possibility to radon to decay into these free spaces rather than radon exhalation. The daughters of the radon decay 214 Bi and 214 Pb reported by gamma measurements of the cement-sand samples. (author)

  16. Interviewer Effects on a Network-Size Filter Question

    Directory of Open Access Journals (Sweden)

    Josten Michael

    2016-06-01

    Full Text Available There is evidence that survey interviewers may be tempted to manipulate answers to filter questions in a way that minimizes the number of follow-up questions. This becomes relevant when ego-centered network data are collected. The reported network size has a huge impact on interview duration if multiple questions on each alter are triggered. We analyze interviewer effects on a network-size question in the mixed-mode survey “Panel Study ‘Labour Market and Social Security’” (PASS, where interviewers could skip up to 15 follow-up questions by generating small networks. Applying multilevel models, we find almost no interviewer effects in CATI mode, where interviewers are paid by the hour and frequently supervised. In CAPI, however, where interviewers are paid by case and no close supervision is possible, we find strong interviewer effects on network size. As the area-specific network size is known from telephone mode, where allocation to interviewers is random, interviewer and area effects can be separated. Furthermore, a difference-in-difference analysis reveals the negative effect of introducing the follow-up questions in Wave 3 on CAPI network size. Attempting to explain interviewer effects we neither find significant main effects of experience within a wave, nor significantly different slopes between interviewers.

  17. The Venice specimen of Ouranosaurus nigeriensis (Dinosauria, Ornithopoda

    Directory of Open Access Journals (Sweden)

    Filippo Bertozzo

    2017-06-01

    Full Text Available Ouranosaurus nigeriensis is an iconic African dinosaur taxon that has been described on the basis of two nearly complete skeletons from the Lower Cretaceous Gadoufaoua locality of the Ténéré desert in Niger. The entire holotype and a few bones attributed to the paratype formed the basis of the original description by Taquet (1976. A mounted skeleton that appears to correspond to O. nigeriensis has been on public display since 1975, exhibited at the Natural History Museum of Venice. It was never explicitly reported whether the Venice specimen represents a paratype and therefore, the second nearly complete skeleton reported in literature or a third unreported skeleton. The purpose of this paper is to disentangle the complex history of the various skeletal remains that have been attributed to Ouranosaurus nigeriensis (aided by an unpublished field map of the paratype and to describe in detail the osteology of the Venice skeleton. The latter includes the paratype material (found in 1970 and collected in 1972, with the exception of the left femur, the right coracoid and one manus ungual phalanx I, which were replaced with plaster copies, and (possibly other manus phalanges. Some other elements (e.g., the first two chevrons, the right femur, the right tibia, two dorsal vertebrae and some pelvic bones were likely added from other individual/s. The vertebral column of the paratype was articulated and provides a better reference for the vertebral count of this taxon than the holotype. Several anatomical differences are observed between the holotype and the Venice specimen. Most of them can be ascribed to intraspecific variability (individual or ontogenetic, but some are probably caused by mistakes in the preparation or assemblage of the skeletal elements in both specimens. The body length of the Venice skeleton is about 90% the linear size of the holotype. Osteohistological analysis (the first for this taxon of some long bones, a rib and a dorsal

  18. The Venice specimen of Ouranosaurus nigeriensis (Dinosauria, Ornithopoda).

    Science.gov (United States)

    Bertozzo, Filippo; Dalla Vecchia, Fabio Marco; Fabbri, Matteo

    2017-01-01

    Ouranosaurus nigeriensis is an iconic African dinosaur taxon that has been described on the basis of two nearly complete skeletons from the Lower Cretaceous Gadoufaoua locality of the Ténéré desert in Niger. The entire holotype and a few bones attributed to the paratype formed the basis of the original description by Taquet (1976). A mounted skeleton that appears to correspond to O. nigeriensis has been on public display since 1975, exhibited at the Natural History Museum of Venice. It was never explicitly reported whether the Venice specimen represents a paratype and therefore, the second nearly complete skeleton reported in literature or a third unreported skeleton. The purpose of this paper is to disentangle the complex history of the various skeletal remains that have been attributed to Ouranosaurus nigeriensis (aided by an unpublished field map of the paratype) and to describe in detail the osteology of the Venice skeleton. The latter includes the paratype material (found in 1970 and collected in 1972), with the exception of the left femur, the right coracoid and one manus ungual phalanx I, which were replaced with plaster copies, and (possibly) other manus phalanges. Some other elements (e.g., the first two chevrons, the right femur, the right tibia, two dorsal vertebrae and some pelvic bones) were likely added from other individual/s. The vertebral column of the paratype was articulated and provides a better reference for the vertebral count of this taxon than the holotype. Several anatomical differences are observed between the holotype and the Venice specimen. Most of them can be ascribed to intraspecific variability (individual or ontogenetic), but some are probably caused by mistakes in the preparation or assemblage of the skeletal elements in both specimens. The body length of the Venice skeleton is about 90% the linear size of the holotype. Osteohistological analysis (the first for this taxon) of some long bones, a rib and a dorsal neural spine

  19. Three-dimensional MR imaging of formaldehyde-fixed specimens using alginate impression material (Jeltrate PlusTM)

    International Nuclear Information System (INIS)

    Kinoshita, Yoshimasa; Okazaki, Keisuke; Kohshi, Kiyotaka; Yokota, Akira; Iriguchi, Norio.

    1998-01-01

    MRI has been widely accepted as one of the most useful techniques for investigations of the brain, liver and other organs. It is difficult, however, to set specimens in a small resonator without problems with air contamination, morphological change due to compression and motion artifact because of poor fixation. We embedded formaldehyde-fixed specimens in an alginate impression material, Jeltrate Plus TM , and set these specimens in a small resonator. Data were acquired using a 3-D steady-state free precession (3D-ssfp) sequence (6 x 6 x 6 cm field of view, echo time 9 ms, repetition time 200 ms, flip angle 90 degrees, 128 x 128 x 128 matrix size, 2 signals averaged per cycle) utilizing a 4.7 Tesla MRI system (SISCO/Varian, SIS 200/400). To reconstruct 3-D representations from 2-D images, background noise of 2-D slices was eliminated, relative optical density normalized and ROI trimmed using National Institute of Health (NIH) Image 1.59 software on a Macintosh computer. In vitro MRI of specimens may be useful to clarify images of anatomical and pathological structures. The alginate impression material was found to be a useful casting substance for postmortem specimens being examined by MRI. (author)

  20. Specimen holder for an electron microscope and device and method for mounting a specimen in an electron microscope

    NARCIS (Netherlands)

    Zandbergen, H.W.; Latenstein van Voorst, A.; Westra, C.; Hoveling, G.H.

    1996-01-01

    A specimen holder for an electron microscope, comprising a bar-shaped body provided adjacent one end with means for receiving a specimen, with means being present for screening the specimen from the environment at least temporarily in airtight and moisture-proof manner in a first position, which

  1. Small-scale Specimen Testing of Monolithic U-Mo Fuel Foils

    Energy Technology Data Exchange (ETDEWEB)

    Ramprashad Prabhakaran; Douglas E. Burkes; James I. Cole; Indrajit Charit; Daniel M. Wachs

    2008-10-01

    The objective of this investigation is to develop a shear punch testing (SPT) procedure and standardize it to evaluate the mechanical properties of irradiated fuels in a hot-cell so that the tensile behavior can be predicted using small volumes of material and at greatly reduced irradiation costs. This is highly important in the development of low-enriched uranium fuels for nuclear research and test reactors. The load-displacement data obtained using SPT can be interpreted in terms of and correlated with uniaxial mechanical properties. In order to establish a correlation between SPT and tensile data, sub-size tensile and microhardness testing were performed on U-Mo alloys. In addition, efforts are ongoing to understand the effect of test parameters (such as specimen thickness, surface finish, punch-die clearance, crosshead velocity and carbon content) on the measured mechanical properties, in order to rationalize the technique, prior to employing it on a material of unknown strength.

  2. Small-scale Specimen Testing of Monolithic U-Mo Fuel Foils

    International Nuclear Information System (INIS)

    Ramprashad Prabhakaran; Douglas E. Burkes; James I. Cole; Indrajit Charit; Daniel M. Wachs

    2008-01-01

    The objective of this investigation is to develop a shear punch testing (SPT) procedure and standardize it to evaluate the mechanical properties of irradiated fuels in a hot-cell so that the tensile behavior can be predicted using small volumes of material and at greatly reduced irradiation costs. This is highly important in the development of low-enriched uranium fuels for nuclear research and test reactors. The load-displacement data obtained using SPT can be interpreted in terms of and correlated with uniaxial mechanical properties. In order to establish a correlation between SPT and tensile data, sub-size tensile and microhardness testing were performed on U-Mo alloys. In addition, efforts are ongoing to understand the effect of test parameters (such as specimen thickness, surface finish, punch-die clearance, crosshead velocity and carbon content) on the measured mechanical properties, in order to rationalize the technique, prior to employing it on a material of unknown strength

  3. A general mixed mode fracture mechanics test specimen: The DCB-specimen loaded with uneven bending moments

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, B.F.; Joergensen, K.; Oestergaard, R.C. [Risoe National Lab., Materials Dept., Roskilde (Denmark); Jacobsen, T.K. [LM Glasfiber A/S, Lunderskov (Denmark)

    2004-03-01

    A mixed mode specimen is proposed for fracture mechanics characterisation of adhesive joints, laminates and multilayers. The specimen is a double cantilever beam specimen loaded with uneven bending moments at the two free beams. By varying the ratio between the two applied moments, the full mode mixity range from pure mode I to pure mode II can be generated for the same specimen geometry. The specimen allows stable crack growth. In case of large scale crack bridging, mixed mode cohesive laws can be obtained by a J integral based approach. As a preliminary example, fracture of adhesive joints between two glass-fibre laminates was studied. The mixed mode fracture resistance increased with increasing crack length due to fibre cross over bridging, eventually reaching a steady-state level (R-curve behaviour). The steady-state fracture toughness level increased with increasing tangential crack opening displacement. Cohesive stresses were determined by a J integral approach. The deducted shear stress was found to be relative high ({approx} = 20 MPa) in comparison with the normal stress ({approx} = 1 MPa). (au)

  4. Operative outcomes of conventional specimen radiography versus in-operating room specimen radiography in radioactive seed-localized segmental mastectomies.

    Science.gov (United States)

    Rhee, Daniel; Pockaj, Barbara; Wasif, Nabil; Stucky, Chee-Chee; Pizzitola, Victor; Giurescu, Marina; Patel, Bhavika; McCarthy, Janice; Gray, Richard

    2018-01-01

    In-operating room specimen radiography (ORSR) has not been studied among women undergoing radioactive seed localization (RSL) for breast cancer surgery and had the potential to decrease operative time and perhaps improve intraoperative margin management. One hundred consecutive RSL segmental mastectomies among 98 patients using ORSR were compared to 100 consecutive segmental mastectomies among 98 patients utilizing conventional radiography (CSR) prior to the initiation of ORSR from December 2013 to January 2015 after radioactive seed localization. Final pathologic margins were considered to be 10 mm for all cases of no residual disease after biopsy or neoadjuvant therapy, but such patients were excluded from analyses involving tumor size. All patients' specimens were subjected to intraoperative pathologic consultation in addition to ORSR or CSR. The median age of the cohort was 65 years (range 36-97), and the median tumor size was 1 cm. There were no differences between the ORSR and CSR groups in age, tumor size, percentage of cases with only DCIS, and percentage of cases with microcalcifications. The ORSR group had a statistically significant lower BMI. Mean operative time from cut-to-close was not significantly different (ORSR 77 min, SD 24.8 vs CSR 76 min, SD 24.8, p = 0.75). There was no statistical difference in mean closest final pathologic margin (4.99 mm, SD 3.3 vs 4.88 mm, SD 3.5, p = 0.9). The percentage undergoing intraoperative margin re-excision (ORSR 40%, CR 47%, p = 0.31) and the mean total number of margins excised intraoperatively (ORSR 0.9, CR 1.0 p = 0.65) were similar. The rate of any margin CSR; this difference was not statistically significant (p = 0.25). The mean ratio of segmental mastectomy volume to maximum tumor diameter was less for ORSR (82.7cm2 vs 139.4cm2, p = 0.014). ORSR for RSL breast surgery, in the setting of routine intraoperative pathology consultation, does not significantly impact operative time, the rate or

  5. The causal effect of board size in the performance of small and medium-sized firms

    DEFF Research Database (Denmark)

    Bennedsen, Morten; Kongsted, Hans Christian; Meisner Nielsen, Kasper

    2008-01-01

    correlation between family size and board size and show this correlation to be driven by firms where the CEO's relatives serve on the board. Second, we find empirical evidence of a small adverse board size effect driven by the minority of small and medium-sized firms that are characterized by having......Empirical studies of large publicly traded firms have shown a robust negative relationship between board size and firm performance. The evidence on small and medium-sized firms is less clear; we show that existing work has been incomplete in analyzing the causal relationship due to weak...... identification strategies. Using a rich data set of almost 7000 closely held corporations we provide a causal analysis of board size effects on firm performance: We use a novel instrument given by the number of children of the chief executive officer (CEO) of the firms. First, we find a strong positive...

  6. Finite element simulations of electrostatic dopant potentials in thin semiconductor specimens for electron holography

    Energy Technology Data Exchange (ETDEWEB)

    Somodi, P.K.; Twitchett-Harrison, A.C.; Midgley, P.A. [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Kardynał, B.E. [Peter Grünberg Institute 9, Forschungszentrum Jülich, D-52425 Jülich (Germany); Barnes, C.H.W. [Department of Physics, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Dunin-Borkowski, R.E., E-mail: rafaldb@gmail.com [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute 5, Forschungszentrum Jülich, D-52425 Jülich (Germany)

    2013-11-15

    Two-dimensional finite element simulations of electrostatic dopant potentials in parallel-sided semiconductor specimens that contain p–n junctions are used to assess the effect of the electrical state of the surface of a thin specimen on projected potentials measured using off-axis electron holography in the transmission electron microscope. For a specimen that is constrained to have an equipotential surface, the simulations show that the step in the projected potential across a p–n junction is always lower than would be predicted from the properties of the bulk device, but is relatively insensitive to the value of the surface state energy, especially for thicker specimens and higher dopant concentrations. The depletion width measured from the projected potential, however, has a complicated dependence on specimen thickness. The results of the simulations are of broader interest for understanding the influence of surfaces and interfaces on electrostatic potentials in nanoscale semiconductor devices. - Highlights: • Finite element simulations are performed to calculate electrostatic dopant potentials in TEM specimens that contain p–n junctions. • The effect of the electrical state of the specimen surface on the projected potential is assessed for equipotential specimen surfaces. • The step in projected potential is always found to be lower than the step in potential in the bulk device. • The step in projected potential is least sensitive to surface state energy for thicker specimens and higher dopant concentrations. • The depletion width measured from the projected potential has a complicated dependence on specimen thickness.

  7. Finite element simulations of electrostatic dopant potentials in thin semiconductor specimens for electron holography

    International Nuclear Information System (INIS)

    Somodi, P.K.; Twitchett-Harrison, A.C.; Midgley, P.A.; Kardynał, B.E.; Barnes, C.H.W.; Dunin-Borkowski, R.E.

    2013-01-01

    Two-dimensional finite element simulations of electrostatic dopant potentials in parallel-sided semiconductor specimens that contain p–n junctions are used to assess the effect of the electrical state of the surface of a thin specimen on projected potentials measured using off-axis electron holography in the transmission electron microscope. For a specimen that is constrained to have an equipotential surface, the simulations show that the step in the projected potential across a p–n junction is always lower than would be predicted from the properties of the bulk device, but is relatively insensitive to the value of the surface state energy, especially for thicker specimens and higher dopant concentrations. The depletion width measured from the projected potential, however, has a complicated dependence on specimen thickness. The results of the simulations are of broader interest for understanding the influence of surfaces and interfaces on electrostatic potentials in nanoscale semiconductor devices. - Highlights: • Finite element simulations are performed to calculate electrostatic dopant potentials in TEM specimens that contain p–n junctions. • The effect of the electrical state of the specimen surface on the projected potential is assessed for equipotential specimen surfaces. • The step in projected potential is always found to be lower than the step in potential in the bulk device. • The step in projected potential is least sensitive to surface state energy for thicker specimens and higher dopant concentrations. • The depletion width measured from the projected potential has a complicated dependence on specimen thickness

  8. Disruption effects on the beam size measurement

    Energy Technology Data Exchange (ETDEWEB)

    Raimondi, P.; Decker, F.J.; Chen, P.

    1995-06-01

    At the SLC Final Focus with higher currents and smaller beam sizes, the disruption parameter D{sub y} is close to one and so the pinch effect should produce a luminosity enhancement. Since a flat beam-beam function is fit to deflection scan data to measure the beam size, disruption can affect the measurement. Here the authors discuss the quantitative effects of disruption for typical SLC beam parameters. With 3.5 10{sup 10} particles per pulse, bunch length of 0.8 mm and beam sizes of 2.1 {mu}m horizontally and 0.55 {mu}m vertically, the measured vertical size can be as much as 25% bigger than the real one. Furthermore during the collision the spot size actually decrease, producing an enhancement factor H{sub D} of about 1.25. This would yield to a true luminosity which is 1.6 times that which is estimated from the beam-beam deflection fit.

  9. Disruption effects on the beam size measurement

    International Nuclear Information System (INIS)

    Raimondi, P.; Decker, F.J.; Chen, P.

    1995-01-01

    At the SLC Final Focus with higher currents and smaller beam sizes, the disruption parameter D y is close to one and so the pinch effect should produce a luminosity enhancement. Since a flat beam-beam function is fit to deflection scan data to measure the beam size, disruption can affect the measurement. Here the authors discuss the quantitative effects of disruption for typical SLC beam parameters. With 3.5 10 10 particles per pulse, bunch length of 0.8 mm and beam sizes of 2.1 μm horizontally and 0.55 μm vertically, the measured vertical size can be as much as 25% bigger than the real one. Furthermore during the collision the spot size actually decrease, producing an enhancement factor H D of about 1.25. This would yield to a true luminosity which is 1.6 times that which is estimated from the beam-beam deflection fit

  10. Assessing the effectiveness of 30% sodium chloride aqueous solution for the preservation of fixed anatomical specimens: a 5-year follow-up study.

    Science.gov (United States)

    de Oliveira, Fabrício Singaretti

    2014-07-01

    Anatomical specimens used in human or veterinary anatomy laboratories are usually prepared with formaldehyde (a cancerous and teratogenic substance), glycerin (an expensive and viscous fluid), or ethanol (which is flammable). This research aimed to verify the viability of an aqueous 30% sodium chloride solution for preservation of anatomical specimens previously fixed with formaldehyde. Anatomical specimens of ruminant, carnivorous, equine, swine and birds were used. All were previously fixed with an aqueous 20% formaldehyde solution and held for 7 days in a 10% aqueous solution of the same active ingredient. During the first phase of the experiment, small specimens of animal tissue previously fixed in formaldehyde were distributed in vials with different concentrations of formaldehyde, with or without 30% sodium chloride solution, a group containing only 30% sodium chloride, and a control group containing only water. During this phase, no contamination was observed in any specimen containing 30% sodium chloride solution, whether alone or in combination with different concentrations of formaldehyde. In the second phase of the experiment, the 30% sodium chloride solution, found to be optimal in the first phase of the experiment, was tested for its long-term preservation properties. For a period of 5 years, the preserved specimens were evaluated three times a week for visual contamination, odors, and changes in color and texture. There was no visual contamination or decay found in any specimen. Furthermore, no strange odors, or changes in color or softness were noted. The 30% sodium chloride solution was determined to be effective in the preservation of anatomic specimens previously fixed in formaldehyde. © 2014 Anatomical Society.

  11. An Evaluation of the Gap Sizes of 3-Unit Fixed Dental Prostheses Milled from Sintering Metal Blocks

    OpenAIRE

    Jung, Jae-Kwan

    2017-01-01

    This study assessed the clinical acceptability of sintering metal-fabricated 3-unit fixed dental prostheses (FDPs) based on gap sizes. Ten specimens were prepared on research models by milling sintering metal blocks or by the lost-wax technique (LWC group). Gap sizes were assessed at 12 points per abutment (premolar and molar), 24 points per specimen (480 points in a total in 20 specimens). The measured points were categorized as marginal, axial wall, and occlusal for assessment in a silicone...

  12. Plane strain fracture toughness tests on 2.4 and 3.9-inch-thick maraging steel specimens at various yield strength levels.

    Science.gov (United States)

    Fisher, D. M.; Repko, A. J.

    1972-01-01

    Tests of bend and compact specimens were conducted according to ASTM Tentative Method E 399-70T on a 200 grade maraging steel over a range of yield strengths from 123 to 234 ksi. The toughness of any given yield strength level was greater for the overaged condition than for the underaged. Some results which met the specimen size requirements of the method were distinctly lower than corresponding results from larger specimens. Inconsistencies in both validation and invalidation of results by the requirement for linearity of the test record were also noted.

  13. Face compression yield strength of the copper-Inconel composite specimen

    International Nuclear Information System (INIS)

    Horie, T.

    1987-05-01

    A new equation for the face compression yield strength of copper-Inconel composite material has been derived. Elastic-plastic finite element analyses were also made for composite specimens with various aspect ratios to examine the edge effect of the specimen. According to the results of both the new equation and the analyses, the face compression yield strength of the composite should be decreased by about 25% from the value obtained with Becker's equation

  14. Effect of temperature upon the fatigue-crack propagation behavior of Inconel 625

    International Nuclear Information System (INIS)

    James, L.A.

    1977-03-01

    The techniques of linear-elastic fracture mechanics were employed to characterize the effect of temperature upon the fatigue-crack propagation behavior of mill-annealed Inconel 625 in an air environment over the range 75 0 - 1200 0 F (24 0 - 649 0 C). In general, fatigue-crack growth rates increased with increasing test temperature. Two different specimen sizes were employed at each test temperature, and no effects of specimen size upon crack growth were noted

  15. A general mixed mode fracture mechanics test specimen: The DCB-specimen loaded with uneven bending moments

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Jørgensen, K.; Jacobsen, T.K.

    2004-01-01

    A mixed mode specimen is proposed for fracture mechanics characterisation of adhesive joints, laminates and multilayers. The specimen is a double cantilever beam specimen loaded with uneven bending moments at the two free beams. By varying the ratiobetween the two applied moments, the full mode...... glass-fibre laminates was studied. The mixed mode fracture resistance increased with increasing crack length due to fibre bridging, eventually reaching asteady-state level (R-curve behaviour). The steady-state fracture toughness level increased with increasing tangential crack opening displacement....

  16. Grain-to-grain variations in NbC particle size distributions in an austenitic stainless steel

    International Nuclear Information System (INIS)

    Barlow, C.Y.; Ralph, B.; Silverman, B.; Jones, A.R.

    1979-01-01

    Quantitative information has been obtained concerning the size distributions of NbC precipitate particles in different grains in a deformed and aged austenitic stainless steel specimen. The precipitate size distributions obtained differ from one grain to another. The average disparity measured between the mean precipitate sizes was a function of the distance between the grains compared. The results obtained are considered in terms of differences in precipitation behaviour due to variations in the levels of plastic strain in constituent grains of the deformed specimen. (author)

  17. Effect of display size on visual attention.

    Science.gov (United States)

    Chen, I-Ping; Liao, Chia-Ning; Yeh, Shih-Hao

    2011-06-01

    Attention plays an important role in the design of human-machine interfaces. However, current knowledge about attention is largely based on data obtained when using devices of moderate display size. With advancement in display technology comes the need for understanding attention behavior over a wider range of viewing sizes. The effect of display size on test participants' visual search performance was studied. The participants (N = 12) performed two types of visual search tasks, that is, parallel and serial search, under three display-size conditions (16 degrees, 32 degrees, and 60 degrees). Serial, but not parallel, search was affected by display size. In the serial task, mean reaction time for detecting a target increased with the display size.

  18. 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.

  19. Influence of different sizes of composite femora on the biomechanical behavior of cementless hip prosthesis.

    Science.gov (United States)

    Schmidutz, Florian; Woiczinski, Mathias; Kistler, Manuel; Schröder, Christian; Jansson, Volkmar; Fottner, Andreas

    2017-01-01

    For the biomechanical evaluation of cementless stems different sizes of composite femurs have been used in the literature. However, the impact of different specimen sizes on test results is unknown. To determine the potential effect of femur size the biomechanical properties of a conventional stem (CLS Spotorno) were examined in 3 different sizes (small, medium and large composite Sawbones®). Primary stability was tested under physiologically adapted dynamic loading conditions measuring 3-dimensional micromotions. For the small composite femur the dynamic load needed to be adapted since fractures occurred when reaching 1700N. Additionally, surface strain distribution was recorded before and after implantation to draw conclusions about the tendency for stress shielding. All tested sizes revealed similar micromotions only reaching a significant different level at one measurement point. The highest micromotions were observed at the tip of the stems exceeding the limit for osseous integration of 150μm. Regarding strain distribution the highest strain reduction after implantation was registered in all sizes at the level of the lesser trochanter. Specimen size seems to be a minor influence factor for biomechanical evaluation of cementless stems. However, the small composite femur is less suitable for biomechanical testing since this size failed under physiological adapted loads. For the CLS Spotorno osseous integration is unlikely at the tip of the stem and the tendency for stress shielding is the highest at the level of the lesser trochanter. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Effect of particle size distribution on sintering of tungsten

    International Nuclear Information System (INIS)

    Patterson, B.R.; Griffin, J.A.

    1984-01-01

    To date, very little is known about the effect of the nature of the particle size distribution on sintering. It is reasonable that there should be an effect of size distribution, and theory and prior experimental work examining the effects of variations in bimodal and continuous distributions have shown marked effects on sintering. Most importantly, even with constant mean particle size, variations in distribution width, or standard deviation, have been shown to produce marked variations in microstructure and sintering rate. In the latter work, in which spherical copper powders were blended to produce lognormal distributions of constant geometric mean particle size by weight frequency, blends with larger values of geometric standard deviation, 1nσ, sintered more rapidly. The goals of the present study were to examine in more detail the effects of variations in the width of lognormal particle size distributions of tungsten powder and determine the effects of 1nσ on the microstructural evolution during sintering

  1. Recent advances in FIB-TEM specimen preparation techniques

    International Nuclear Information System (INIS)

    Li Jian; Malis, T.; Dionne, S.

    2006-01-01

    Preparing high-quality transmission electron microscopy (TEM) specimens is of paramount importance in TEM studies. The development of the focused ion beam (FIB) microscope has greatly enhanced TEM specimen preparation capabilities. In recent years, various FIB-TEM foil preparation techniques have been developed. However, the currently available techniques fail to produce TEM specimens from fragile and ultra-fine specimens such as fine fibers. In this paper, the conventional FIB-TEM specimen preparation techniques are reviewed, and their advantages and shortcomings are compared. In addition, a new technique suitable to prepare TEM samples from ultra-fine specimens is demonstrated

  2. FIRM SIZE EFFECTS ON TRANSACTION COSTS

    NARCIS (Netherlands)

    NOOTEBOOM, B

    1993-01-01

    Associated with effects of scale, scope, experience and learning there are effects of firm size on transaction costs; in the stages of contact, contract and control. These effects are due to ''threshold costs'' in setting up contacts, contracts and governance schemes, and to differences with respect

  3. Reliability of 46,XX results on miscarriage specimens: a review of 1,222 first-trimester miscarriage specimens.

    Science.gov (United States)

    Lathi, Ruth B; Gustin, Stephanie L F; Keller, Jennifer; Maisenbacher, Melissa K; Sigurjonsson, Styrmir; Tao, Rosina; Demko, Zach

    2014-01-01

    To examine the rate of maternal contamination in miscarriage specimens. Retrospective review of 1,222 miscarriage specimens submitted for chromosome testing with detection of maternal cell contamination (MCC). Referral centers requesting genetic testing of miscarriage specimens at a single reference laboratory. Women with pregnancy loss who desire complete chromosome analysis of the pregnancy tissue. Analysis of miscarriage specimens using single-nucleotide polymorphism (SNP) microarray technology with bioinformatics program to detect maternal cell contamination. Chromosome content of miscarriages and incidence of 46,XX results due to MCC. Of the 1,222 samples analyzed, 592 had numeric chromosomal abnormalities, and 630 were normal 46,XX or 46,XY (456 and 187, respectively). In 269 of the 46,XX specimens, MCC with no embryonic component was found. With the exclusion of maternal 46,XX results, the chromosomal abnormality rate increased from 48% to 62%, and the ratio for XX to XY results dropped from 2.6 to 1.0. Over half of the normal 46,XX results in miscarriage specimens were due to MCC. The use of SNPs in MCC testing allows for precise identification of chromosomal abnormalities in miscarriage as well as MCC, improving the accuracy of products of conception testing. Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  4. Effect of grain size upon the fatigue-crack propagation behavior of alloy 718 under hold-time cycling at elevated temperature

    Energy Technology Data Exchange (ETDEWEB)

    James, L A

    1986-01-01

    Fatigue-crack propagation tests were conducted in air at 538/sup 0/C on several specimens of Alloy 718 representing several different producers, melt practices and product forms. This variety resulted in a range of grain sizes from ASTM Size 5 to 11.5. Tests at low cyclic frequency employing a tensile hold-time revealed a relationship between crack growth rates and grain size: higher growth rates were associated with fine-grain material and lower rates with larger-grain material. The lowest crack growth rates were associated with a necklace microstructure, whereby large grains are associated with necklaces of very small grains.

  5. Development of neural basis for chinese orthographic neighborhood size effect.

    Science.gov (United States)

    Zhao, Jing; Li, Qing-Lin; Ding, Guo-Sheng; Bi, Hong-Yan

    2016-02-01

    The brain activity of orthographic neighborhood size (N size) effect in Chinese character naming has been studied in adults, meanwhile behavioral studies have revealed a developmental trend of Chinese N-size effect in developing readers. However, it is unclear whether and how the neural mechanism of N-size effect changes in Chinese children along with development. Here we address this issue using functional magnetic resonance imaging. Forty-four students from the 3(rd) , 5(th) , and 7(th) grades were scanned during silent naming of Chinese characters. After scanning, all participants took part in an overt naming test outside the scanner, and results of the naming task showed that the 3(rd) graders named characters from large neighborhoods faster than those from small neighborhoods, revealing a facilitatory N-size effect; the 5(th) graders showed null N-size effect while the 7(th) graders showed an inhibitory N-size effect. Neuroimaging results revealed that only the 3(rd) graders exhibited a significant N-size effect in the left middle occipital activity, with greater activation for large N-size characters. Results of 5(th) and 7(th) graders showed significant N-size effects in the left middle frontal gyrus, in which 5(th) graders induced greater activation in large N-size condition than in small N-size condition, while 7(th) graders exhibited an opposite effect which was similar to the adult pattern reported in a previous study. The current findings suggested the transition from broadly tuned to finely tuned orthographic representation with reading development, and the inhibition from neighbors' phonology for higher graders. Hum Brain Mapp 37:632-647, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  6. Design of specimen for weld residual stress simulation

    International Nuclear Information System (INIS)

    Kim, Jin Weon; Park, Jong Sun; Lee, Kyung Soo

    2008-01-01

    The objective of this study is to design a laboratory specimen for simulating residual stress of circumferential butt welding of pipe. Specimen type and method for residual stress generation were proposed based on the review of prior studies and parametric finite element simulation. To prove the proposed specimen type and loading method, the residual stress was generated using the designed specimen by applying proposed method and was measured. The measured residual stress using X-ray diffraction reasonably agreed with the results of finite element simulation considered in the specimen design. Comparison of residual strains measured at several locations of specimen and given by finite element simulation also showed good agreement. Therefore, it is indicated that the designed specimen can reasonably simulate the residual stress of circumferential butt welding of pipe

  7. Shear and foundation effects on crack root rotation and mode-mixity in moment- and force-loaded single cantilever beam sandwich specimen

    DEFF Research Database (Denmark)

    Saseendran, Vishnu; Carlsson, Leif A.; Berggreen, Christian

    2017-01-01

    Foundation effects play a crucial role in sandwich fracture specimens with a soft core. Accurate estimation of deformationcharacteristics at the crack front is vital in understanding compliance, energy release rate and mode-mixity infracture test specimens. Beam on elastic foundation analysis...... modulus is proposed that closely agrees with the numerical compliance and energy release rate results forall cases considered. An analytical expression for crack root rotation of the loaded upper face sheet provides consistentresults for both loading configurations. For the force-loaded single cantilever...

  8. Effect Size in Efficacy Trials of Women With Decreased Sexual Desire.

    Science.gov (United States)

    Pyke, Robert E; Clayton, Anita H

    2018-03-22

    Regarding hypoactive sexual desire disorder (HSDD) in women, some reviewers judge the effect size small for medications vs placebo, but substantial for cognitive behavior therapy (CBT) or mindfulness meditation training (MMT) vs wait list. However, we lack comparisons of the effect sizes for the active intervention itself, for the control treatment, and for the differential between the two. For efficacy trials of HSDD in women, compare effect sizes for medications (testosterone/testosterone transdermal system, flibanserin, and bremelanotide) and placebo vs effect sizes for psychotherapy and wait-list control. We conducted a literature search for mean changes and SD on main measures of sexual desire and associated distress in trials of medications, CBT, or MMT. Effect size was used as it measures the magnitude of the intervention without confounding by sample size. Cohen d was used to determine effect sizes. For medications, mean (SD) effect size was 1.0 (0.34); for CBT and MMT, 1.0 (0.36); for placebo, 0.55 (0.16); and for wait list, 0.05 (0.26). Recommendations of psychotherapy over medication for treatment of HSDD are premature and not supported by data on effect sizes. Active participation in treatment conveys considerable non-specific benefits. Caregivers should attend to biological and psychosocial elements, and patient preference, to optimize response. Few clinical trials of psychotherapies were substantial in size or utilized adequate control paradigms. Medications and psychotherapies had similar, large effect sizes. Effect size of placebo was moderate. Effect size of wait-list control was very small, about one quarter that of placebo. Thus, a substantial non-specific therapeutic effect is associated with receiving placebo plus active care and evaluation. The difference in effect size between placebo and wait-list controls distorts the value of the subtraction of effect of the control paradigms to estimate intervention effectiveness. Pyke RE, Clayton AH

  9. Comparison of gross anatomy test scores using traditional specimens vs. QuickTime Virtual Reality animated specimens

    Science.gov (United States)

    Maza, Paul Sadiri

    In recent years, technological advances such as computers have been employed in teaching gross anatomy at all levels of education, even in professional schools such as medical and veterinary medical colleges. Benefits of computer based instructional tools for gross anatomy include the convenience of not having to physically view or dissect a cadaver. Anatomy educators debate over the advantages versus the disadvantages of computer based resources for gross anatomy instruction. Many studies, case reports, and editorials argue for the increased use of computer based anatomy educational tools, while others discuss the necessity of dissection for various reasons important in learning anatomy, such as a three-dimensional physical view of the specimen, physical handling of tissues, interactions with fellow students during dissection, and differences between specific specimens. While many articles deal with gross anatomy education using computers, there seems to be a lack of studies investigating the use of computer based resources as an assessment tool for gross anatomy, specifically using the Apple application QuickTime Virtual Reality (QTVR). This study investigated the use of QTVR movie modules to assess if using computer based QTVR movie module assessments were equal in quality to actual physical specimen examinations. A gross anatomy course in the College of Veterinary Medicine at Cornell University was used as a source of anatomy students and gross anatomy examinations. Two groups were compared, one group taking gross anatomy examinations in a traditional manner, by viewing actual physical specimens and answering questions based on those specimens. The other group took the same examinations using the same specimens, but the specimens were viewed as simulated three-dimensional objects in a QTVR movie module. Sample group means for the assessments were compared. A survey was also administered asking students' perceptions of quality and user-friendliness of the QTVR

  10. The Static and Fatigue Behavior of AlSiMg Alloy Plain, Notched, and Diamond Lattice Specimens Fabricated by Laser Powder Bed Fusion

    Directory of Open Access Journals (Sweden)

    Hugo Soul

    2018-04-01

    Full Text Available The fabrication of engineered lattice structures has recently gained momentum due to the development of novel additive manufacturing techniques. Interest in lattice structures resides not only in the possibility of obtaining efficient lightweight materials, but also in the functionality of pre-designed architectured structures for specific applications, such as biomimetic implants, chemical catalyzers, and heat transfer devices. The mechanical behaviour of lattice structures depends not only the composition of the base material, but also on the type and size of the unit cells, as well as on the material microstructure resulting from a specific fabrication procedure. The present work focuses on the static and fatigue behavior of diamond cell lattice structures fabricated from an AlSiMg alloy by laser powder bed fusion technology. In particular, the specimens were fabricated with three different orientations of lattice cells—[001], [011], [111]—and subjected to static tensile testing and force-controlled pull–pull fatigue testing up to 1 × 107 cycles. In parallel, the mechanical behavior of dense tensile plain and notched specimens was also studied and compared to that of their lattice counterparts. Results showed a significant effect of the cell orientation on the fatigue lives: specimens oriented at [001] were ~30% more fatigue-resistant than specimens oriented at [011] and [111].

  11. Fracture assessment of HSST Plate 14 shallow-flaw cruciform bend specimens tested under biaxial loading conditions

    Energy Technology Data Exchange (ETDEWEB)

    Bass, B.R.; McAfee, W.J.; Williams, P.T.; Pennell, W.E.

    1998-06-01

    A technology to determine shallow-flaw fracture toughness of reactor pressure vessel (RPV) steels is being developed for application to the safety assessment of RPVs containing postulated shallow surface flaws. Matrices of cruciform beam tests were developed to investigate and quantify the effects of temperature, biaxial loading, and specimen size on fracture initiation toughness of two-dimensional (constant depth), shallow, surface flaws. The cruciform beam specimens were developed at Oak Ridge National Laboratory (ORNL) to introduce a far-field, out-of-plane biaxial stress component in the test section that approximates the nonlinear stresses resulting from pressurized-thermal-shock or pressure-temperature loading of an RPV. Tests were conducted under biaxial load ratios ranging from uniaxial to equibiaxial. These tests demonstrated that biaxial loading can have a pronounced effect on shallow-flaw fracture toughness in the lower transition temperature region for an RPV material. The cruciform fracture toughness data were used to evaluate fracture methodologies for predicting the observed effects of biaxial loading on shallow-flaw fracture toughness. Initial emphasis was placed on assessment of stress-based methodologies, namely, the J-Q formulation, the Dodds-Anderson toughness scaling model, and the Weibull approach. Applications of these methodologies based on the hydrostatic stress fracture criterion indicated an effect of loading-biaxiality on fracture toughness; the conventional maximum principal stress criterion indicated no effect. A three-parameter Weibull model based on the hydrostatic stress criterion is shown to correlate the experimentally observed biaxial effect on cleavage fracture toughness by providing a scaling mechanism between uniaxial and biaxial loading states.

  12. Evaluation of irradiated coating material specimens

    International Nuclear Information System (INIS)

    Lee, Yong Jin; Nam, Seok Woo; Cho, Lee Moon

    2007-12-01

    Evaluation result of irradiated coating material specimens - Coating material specimens radiated Gamma Energy(Co 60) in air condition. - Evaluation conditions was above 1 X 10 4 Gy/hr, and radiated TID 2.0 X 10 6 Gy. - The radiated coating material specimens, No Checking, Cracking, Flaking, Delamination, Peeling and Blistering. - Coating system at the Kori no. 1 and APR 1400 Nuclear power plant, evaluation of irradiated coating materials is in accordance with owner's requirement(2.0 X 10 6 Gy)

  13. Digitizing specimens in a small herbarium: A viable workflow for collections working with limited resources.

    Science.gov (United States)

    Harris, Kari M; Marsico, Travis D

    2017-04-01

    Small herbaria represent a significant portion of herbaria in the United States, but many are not digitizing their collections. At the Arkansas State University Herbarium (STAR), we have created a viable workflow to help small herbaria begin the digitization process, including suggestions for publishing data on the Internet. We calculated hourly rates of each phase of the digitization process. We also mapped accessions at the county level to determine geographic strengths in the collection. All 17,678 accessioned flowering plant specimens at STAR are imaged, databased in Specify, and available electronically on the herbarium's website. Students imaged the specimens at a mean rate of 145/h. We found differences in databasing rates between the graduate student leading the project (47/h) and undergraduate assistants (25/h). The majority of specimens at STAR were collected within the counties neighboring the institution. With this workflow, we estimate that one person can digitize a 20,000-specimen collection in less than 2.5 yr by working only 10 h/wk. Because STAR is a small herbarium with limited resources, the application of the workflow described should assist curators of similar-sized collections as they contemplate and undertake the digitization process.

  14. The Role of Social Norms in the Portion Size Effect: Reducing normative relevance reduces the effect of portion size on consumption decisions

    Directory of Open Access Journals (Sweden)

    Iris eVersluis

    2016-05-01

    Full Text Available People typically eat more from large portions of food than from small portions. An explanation that has often been given for this so-called portion size effect is that the portion size acts as a social norm and as such communicates how much is appropriate to eat. In this paper, we tested this explanation by examining whether manipulating the relevance of the portion size as a social norm changes the portion size effect, as assessed by prospective consumption decisions. We conducted one pilot experiment and one full experiment in which participants respectively indicated how much they would eat or serve themselves from a given amount of different foods. In the pilot (N = 63, we manipulated normative relevance by allegedly basing the portion size on the behavior of either students of the own university (in-group or of another university (out-group. In the main experiment (N = 321, we told participants that either a minority or majority of people similar to them approved of the portion size. Results show that in both experiments, participants expected to serve themselves and to eat more from larger than from smaller portions. As expected, however, the portion size effect was less pronounced when the reference portions were allegedly based on the behavior of an out-group (pilot or approved only by a minority (main experiment. These findings suggest that the portion size indeed provides normative information, because participants were less influenced by it if it communicated the behaviors or values of a less relevant social group. In addition, in the main experiment, the relation between portion size and the expected amount served was partially mediated by the amount that was considered appropriate, suggesting that concerns about eating an appropriate amount indeed play a role in the portion size effect. However, since the portion size effect was weakened but not eliminated by the normative relevance manipulations and since mediation was only partial

  15. System for the continuous irradiation of specimens, especially for activation analysis

    International Nuclear Information System (INIS)

    Dieck, L.E.

    1975-01-01

    The system is to ensure a continuous irradiation of several specimens, especially for activation analysis. The specimens rotate in a hollow body which is axially movable along a rail. The rotation is effected by a turbine driven by hydraulic or pneumatic power and placed in the hollow body which can be used for example in the rabbit system of a nuclear reactor. The driving medium serves both as conveying medium for the system and drive for the rotating drum and as coolant for the specimens and results in radiation protection. The geometric arrangement and design of both the turbine and the whole system is decribed in detail. (UWI) [de

  16. XRD characterisation of nanoparticle size and shape distributions

    International Nuclear Information System (INIS)

    Armstrong, N.; Kalceff, W.; Cline, J.P.; Bonevich, J.

    2004-01-01

    Full text: The form of XRD lines and the extent of their broadening provide useful structural information about the shape, size distribution, and modal characteristics of the nanoparticles comprising the specimen. Also, the defect content of the nanoparticles can be determined, including the type, dislocation density, and stacking faults/twinning. This information is convoluted together and can be grouped into 'size' and 'defect' broadening contributions. Modern X-ray diffraction analysis techniques have concentrated on quantifying the broadening arising from the size and defect contributions, while accounting for overlapping of profiles, instrumental broadening, background scattering and noise components. We report on a combined Bayesian/Maximum Entropy (MaxEnt) technique developed for use in the certification of a NIST Standard Reference Material (SRM) for size-broadened line profiles. The approach used was chosen because of its generality in removing instrumental broadening from the observed line profiles, and its ability to determine not only the average crystallite size, but also the distribution of sizes and the average shape of crystallites. Moverover, this Bayesian/MaxEnt technique is fully quantitative, in that it also determines uncertainties in the crystallite-size distribution and other parameters. Both experimental and numerical simulations of size broadened line-profiles modelled on a range of specimens with spherical and non-spherical morphologies are presented to demonstrate how this information can be retrieved from the line profile data. The sensitivity of the Bayesian/MaxEnt method to determining the size distribution using varying a priori information are emphasised and discussed

  17. Measurements and Counts for Notacanthidae Specimens

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Taxonomic data were collected for specimens of deep-sea spiny eels (Notacanthidae) from the Hawaiian Ridge by Bruce C. Mundy. Specimens were collected off the north...

  18. Influence of side-groove root radius on the ductile fracture toughness of miniature C(T) specimens

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E.; Scibetta, M.

    2009-05-15

    The use of miniature C(T) specimens, MC(T), for fracture toughness measurements in the upper shelf regime has been investigated at SCK-CEN since 2004, in the framework of the Electrabel/Tractebel SCK-CEN Convention (now General Framework Agreement SUEZ-SCK-CEN). This geometry has been used and validated on both unirradiated (2004-05) and irradiated (2006) materials, mainly reactor pressure vessel (RPV) steels. While side-grooved MC(T) specimens have shown in all conditions a systematically lower tearing resistance and ductile crack initiation toughness as compared to standard-size 1TC(T) samples, the only plain-sided MC(T) specimen tested in 2005 exhibited very high ductile fracture toughness, thus pointing at a strong influence of side-grooving on the upper shelf properties of MC(T) specimens. This study investigates the influence of side-grooving on the initiation toughness and tearing resistance of MC(T) specimens, as a function of the root radius of the side-groove (ranging from 0.1 to 1 mm) and in comparison with plain-sided MC(T) and reference 1TC(T) samples. The material used is the well characterized DIN 22NiMoCr37 RPV steel, which had been used in the European project which generated the famous EURO fracture toughness data set.

  19. Experimental investigation of effect of specimen thickness on fracture toughness of Al-TiC composites

    Directory of Open Access Journals (Sweden)

    M. S. Raviraj

    2016-07-01

    Full Text Available In this paper, the macro and micro-mechanical fracture behavior was studied for aluminum (Al6061 alloy matrix, reinforced with various proportions of TiC particles such as 3wt%, 5wt% and 7wt%. The Al6061-TiC metal matrix composites were produced by stir casting method to ensure uniform distribution of the TiC particulates in the Al matrix. The compact tension (CT specimens were machined according to ASTM E399 specifications to evaluate the fracture toughness for Al6061-TiC metal matrix composites. The CT specimens were machined for crack to width (a/W ratio of 0.5 and thickness to width (B/W ratios of 0.2 to 0.7 with an increment of 0.1. Load versus crack mouth opening displacement (CMOD data was plotted to estimate stress intensity factor KQ for various thicknesses of the specimen. The fracture toughness KIC was obtained by plotting stress intensity factor versus thickness to width ratios of specimen data. The fracture toughness of these composites varied between 16.4-19.2 MPa√m. Scanning Electron Microscope (SEM studies was made on the fractured surface of the specimens to understand the micro-mechanisms of failure involved in these composites. Void initiation is more significant in the matrix near the interface. The micro-cracks grow from these micro-voids and crack propagates by linking these micro cracks locating the crack path preferentially in the matrix adjacent to the interface indicating ductile fracture.

  20. Thermo-mechanical Fatigue Failure of Thermal Barrier Coated Superalloy Specimen

    Science.gov (United States)

    Subramanian, Rajivgandhi; Mori, Yuzuru; Yamagishi, Satoshi; Okazaki, Masakazu

    2015-09-01

    Failure behavior of thermal barrier coated (TBC) Ni-based superalloy specimens were studied from the aspect of the effect of bond coat material behavior on low cycle fatigue (LCF) and thermo-mechanical fatigue (TMF) at various temperatures and under various loading conditions. Initially, monotonic tensile tests were carried out on a MCrAlY alloy bond coat material in the temperature range of 298 K to 1273 K (25 °C to 1000 °C). Special attention was paid to understand the ductile to brittle transition temperature (DBTT). Next, LCF and TMF tests were carried out on the thermal barrier coated Ni-based alloy IN738 specimen. After these tests, the specimens were sectioned to understand their failure mechanisms on the basis of DBTT of the bond coat material. Experimental results demonstrated that the LCF and TMF lives of the TBC specimen were closely related to the DBTT of the bond coat material, and also the TMF lives were different from those of LCF tests. It has also been observed that the crack density in the bond coat in the TBC specimen was significantly dependent on the test conditions. More importantly, not only the number of cracks but also the crack penetration probability into substrate were shown to be sensitive to the DBTT.

  1. Family size and effective population size in a hatchery stock of coho salmon (Oncorhynchus kisutch)

    Science.gov (United States)

    Simon, R.C.; McIntyre, J.D.; Hemmingsen, A.R.

    1986-01-01

    Means and variances of family size measured in five year-classes of wire-tagged coho salmon (Oncorhynchus kisutch) were linearly related. Population effective size was calculated by using estimated means and variances of family size in a 25-yr data set. Although numbers of age 3 adults returning to the hatchery appeared to be large enough to avoid inbreeding problems (the 25-yr mean exceeded 4500), the numbers actually contributing to the hatchery production may be too low. Several strategies are proposed to correct the problem perceived. Argument is given to support the contention that the problem of effective size is fairly general and is not confined to the present study population.

  2. Measuring wage effects of plant size

    DEFF Research Database (Denmark)

    Albæk, Karsten; Arai, Mahmood; Asplund, Rita

    1998-01-01

    There are large plant size–wage effects in the Nordic countries after taking into account individual and job characteristics as well as systematical sorting of the workers into various plant-sizes. The plant size–wage elasticities we obtain are, in contrast to other dimensions of the wage distrib......–wage elasticity. Our results indicate that using size–class midpoints yields essentially the same results as using exact measures of plant size...

  3. Measuring ERCC1 protein expression in cancer specimens

    DEFF Research Database (Denmark)

    Smith, David Hersi; Fiehn, Anne-Marie Kanstrup; Fogh, Louise

    2014-01-01

    Platinum chemotherapy remains part of standard therapies in the management of a variety of cancers. Severe side effects and a high degree of resistance to platinum drugs have led numerous researchers to search for predictive biomarkers, which could aid in identifying patients that are the most......, the specificity of antibody 4F9 was tested by immunoblotting, immunohistochemistry and immunofluorescence. Scoring guidelines to aid in the evaluation of ERCC1 tumor expression were developed and evaluated in archival formalin-fixed paraffin embedded colorectal cancer specimens. Antibody 4F9 was found...... to be specific by all methods applied and it was possible to evaluate the ERCC1 expression in the majority (85%) of colorectal cancer tumor specimens....

  4. Fatigue Failure Modes of the Grain Size Transition Zone in a Dual Microstructure Disk

    Science.gov (United States)

    Gabb, Timothy P.; Kantzos, Pete T.; Palsa, Bonnie; Telesman, Jack; Gayda, John; Sudbrack, Chantal K.

    2012-01-01

    Mechanical property requirements vary with location in nickel-based superalloy disks. In order to maximize the associated mechanical properties, heat treatment methods have been developed for producing tailored grain microstructures. In this study, fatigue failure modes of a grain size transition zone in a dual microstructure disk were evaluated. A specialized heat treatment method was applied to produce varying grain microstructure in the bore to rim portions of a powder metallurgy processed nickel-based superalloy disk. The transition in grain size was concentrated in a zone of the disk web, between the bore and rim. Specimens were extracted parallel and transversely across this transition zone, and multiple fatigue tests were performed at 427 C and 704 C. Grain size distributions were characterized in the specimens, and related to operative failure initiation modes. Mean fatigue life decreased with increasing maximum grain size, going out through the transition zone. The scatter in limited tests of replicates was comparable for failures of uniform gage specimens in all transition zone locations examined.

  5. Technique of manufacturing specimen of irradiated fuel rods

    International Nuclear Information System (INIS)

    Min, Duck Seok; Seo, Hang Seok; Min, Duck Kee; Koo, Dae Seo; Lee, Eun Pyo; Yang, Song Yeol

    1999-04-01

    Technique of manufacturing specimen of irradiated fuel rods to perform efficient PIE is developed by analyzing the relation between requiring time of manufacturing specimen and manufacturing method in irradiated fuel rods. It takes within an hour to grind 1 mm of specimen thickness under 150 rpm in speed of grinding, 600 g gravity in force using no.120, no.240, no.320 of grinding paper. In case of no.400 of grinding paper, it takes more an hour to grind the same thickness as above. It takes up to a quarter to grind 80-130 μm in specimen thickness using no.400 of grinding paper. When grinding time goes beyond 15 minutes, the grinding thickness of specimen does not exist. The polishing of specimen with 150 Rpms in speed of grinding machine, 600 g gravity in force, 10 minutes in polishing time using diamond paste 15 μm on polishing cloths amounts to 50 μm in specimen thickness. In case of diamond paste 9 μm on polishing cloth, the polishing of specimen amounts to 20 μm. The polishing thickness of specimen with 15 minutes in polishing time using 6 μm, 3 μm, 1 μm, 1/4 μm does not exist. Technique of manufacturing specimen of irradiated fuel rods will have application to the destructive examination of PIE. (author). 6 refs., 1 tab., 10 figs

  6. Effectiveness of a Novel Specimen Collection System in Reducing Blood Culture Contamination Rates.

    Science.gov (United States)

    Bell, Mary; Bogar, Catherine; Plante, Jessica; Rasmussen, Kristen; Winters, Sharon

    2018-04-20

    False-positive blood-culture results due to skin contamination of samples remain a persistent problem for health care providers. Our health system recognized that our rates of contamination across the 4 emergency department campuses were above the national average. A unique specimen collection system was implemented throughout the 4 emergency departments and became the mandatory way to collect adult blood cultures. The microbiology laboratory reported contamination rates weekly to manage potential problems; 7 months of data are presented here. There was an 82.8% reduction in false positives with the unique specimen collection system compared with the standard method (chi-squared test with Yates correction, 2-tailed, P = 0.0001). Based on the historical 3.52% rate of blood-culture contamination for our health facilities, 2.92 false positives were prevented for every 100 blood cultures drawn, resulting from adoption of the unique specimen collection system as the standard of care. This unique collection system can reduce the risk of blood culture contamination significantly and is designed to augment, rather than replace, the standard phlebotomy protocol already in use in most health care settings. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. The detection of tightly closed flaws by nondestructive testing (NDT) methods. [fatigue crack formation in aluminum alloy test specimens

    Science.gov (United States)

    Rummel, W. D.; Rathke, R. A.; Todd, P. H., Jr.; Mullen, S. J.

    1975-01-01

    Liquid penetrant, ultrasonic, eddy current and X-radiographic techniques were optimized and applied to the evaluation of 2219-T87 aluminum alloy test specimens in integrally stiffened panel, and weld panel configurations. Fatigue cracks in integrally stiffened panels, lack-of-fusion in weld panels, and fatigue cracks in weld panels were the flaw types used for evaluation. A 2319 aluminum alloy weld filler rod was used for all welding to produce the test specimens. Forty seven integrally stiffened panels containing a total of 146 fatigue cracks, ninety three lack-of-penetration (LOP) specimens containing a total of 239 LOP flaws, and one-hundred seventeen welded specimens containing a total of 293 fatigue cracks were evaluated. Nondestructive test detection reliability enhancement was evaluated during separate inspection sequences in the specimens in the 'as-machined or as-welded', post etched and post proof loaded conditions. Results of the nondestructive test evaluations were compared to the actual flaw size obtained by measurement of the fracture specimens after completing all inspection sequences. Inspection data were then analyzed to provide a statistical basis for determining the flaw detection reliability.

  8. Experimental and Numerical Investigations on Feasibility and Validity of Prismatic Rock Specimen in SHPB

    Directory of Open Access Journals (Sweden)

    Xibing Li

    2016-01-01

    Full Text Available The paper presents experimental and numerical studies on the feasibility and validity of using prismatic rock specimens in split Hopkinson pressure bar (SHPB test. Firstly, the experimental tests are conducted to evaluate the stress and strain uniformity in the prismatic specimens during impact loading. The stress analysis at the ends of the specimen shows that stress equilibrium can be achieved after about three wave reflections in the specimen, and the balance can be well maintained for a certain time after peak stress. The strain analysis reveals that the prismatic specimen deforms uniformly during the dynamic loading period. Secondly, numerical simulation is performed to further verify the stress and strain uniformity in the prismatic specimen in SHPB test. It indicates that the stress equilibrium can be achieved in prismatic specimen despite a certain degree of stress concentration at the corners. The comparative experiments demonstrate that the change of specimen shape has no significant effect on dynamic responses and failure patterns of the specimen. Finally, a dynamic crack propagation test is presented to show the application of the present work in studying fracturing mechanisms under dynamic loading.

  9. Effects of specimen size and crack depth ratio on calibration curves for modified compact tension specimens

    Czech Academy of Sciences Publication Activity Database

    Seitl, Stanislav; Viszlay, V.; Cifuentes, H.; Canteli, A.

    2015-01-01

    Roč. 15, č. 2 (2015) ISSN 1804-4824 Institutional support: RVO:68081723 Keywords : Modified compact tension test * fracture * concrete * core drill * stress intensity factor Subject RIV: JL - Materials Fatigue, Friction Mechanics

  10. Specimen loading list for the varying temperature experiment

    International Nuclear Information System (INIS)

    Qualls, A.L.; Sitterson, R.G.

    1998-01-01

    The varying temperature experiment HFIR-RB-13J has been assembled and inserted in the reactor. Approximately 5300 specimens were cleaned, inspected, matched, and loaded into four specimen holders. A listing of each specimen loaded into the steady temperature holder, its position in the capsule, and the identification of the corresponding specimen loaded into the varying temperature holder is presented in this report

  11. Recent advances on Charpy specimen reconstitution techniques

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Arnaldo H.P.; Lobo, Raquel M.; Miranda, Carlos Alexandre J., E-mail: aandrade@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2017-07-01

    Charpy specimen reconstitution is widely used around the world as a tool to enhance or supplement surveillance programs of nuclear reactor pressure vessels. The reconstitution technique consists in the incorporation of a small piece from a previously tested specimen into a compound specimen, allowing to increase the number of tests. This is especially important if the available materials is restricted and fracture mechanics parameter have to be determined. The reconstitution technique must fulfill some demands, among them tests results like the original standard specimens and the loaded material of the insert must not be influenced by the welding and machining procedure. It is known that reconstitution of Charpy specimens may affect the impact energy in a consequence of the constraint of plastic deformation by the hardened weldment and HAZ. This paper reviews some recent advances of the reconstitution technique and its applications. (author)

  12. Recent advances on Charpy specimen reconstitution techniques

    International Nuclear Information System (INIS)

    Andrade, Arnaldo H.P.; Lobo, Raquel M.; Miranda, Carlos Alexandre J.

    2017-01-01

    Charpy specimen reconstitution is widely used around the world as a tool to enhance or supplement surveillance programs of nuclear reactor pressure vessels. The reconstitution technique consists in the incorporation of a small piece from a previously tested specimen into a compound specimen, allowing to increase the number of tests. This is especially important if the available materials is restricted and fracture mechanics parameter have to be determined. The reconstitution technique must fulfill some demands, among them tests results like the original standard specimens and the loaded material of the insert must not be influenced by the welding and machining procedure. It is known that reconstitution of Charpy specimens may affect the impact energy in a consequence of the constraint of plastic deformation by the hardened weldment and HAZ. This paper reviews some recent advances of the reconstitution technique and its applications. (author)

  13. Mitogenomes from type specimens, a genotyping tool for morphologically simple species: ten genomes of agar-producing red algae.

    Science.gov (United States)

    Boo, Ga Hun; Hughey, Jeffery R; Miller, Kathy Ann; Boo, Sung Min

    2016-10-14

    DNA sequences from type specimens provide independent, objective characters that enhance the value of type specimens and permit the correct application of species names to phylogenetic clades and specimens. We provide mitochondrial genomes (mitogenomes) from archival type specimens of ten species in agar-producing red algal genera Gelidium and Pterocladiella. The genomes contain 43-44 genes, ranging in size from 24,910 to 24,970 bp with highly conserved gene synteny. Low Ka/Ks ratios of apocytochrome b and cytochrome oxidase genes support their utility as markers. Phylogenies of mitogenomes and cox1+rbcL sequences clarified classification at the genus and species levels. Three species formerly in Gelidium and Pterocladia are transferred to Pterocladiella: P. media comb. nov., P. musciformis comb. nov., and P. luxurians comb. and stat. nov. Gelidium sinicola is merged with G. coulteri because they share identical cox1 and rbcL sequences. We describe a new species, Gelidium millariana sp. nov., previously identified as G. isabelae from Australia. We demonstrate that mitogenomes from type specimens provide a new tool for typifying species in the Gelidiales and that there is an urgent need for analyzing mitogenomes from type specimens of red algae and other morphologically simple organisms for insight into their nomenclature, taxonomy and evolution.

  14. Size-effects in porous metals

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    The intrinsic size-effect for porous metals is investigated. The analyses are carried out numerically using a finite strain generalization of a higher order strain gradient plasticity model. Results for plane strain growth of cylindrical voids are presented in terms of response curves and curves...

  15. Size-effects in porous metals

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    2007-01-01

    The intrinsic size-effect for porous metals is investigated. The analyses are carried out numerically using a finite strain generalization of a higher order strain gradient plasticity model. Results for plane strain growth of cylindrical voids are presented in terms of response curves and curves...

  16. Sequence Capture and Phylogenetic Utility of Genomic Ultraconserved Elements Obtained from Pinned Insect Specimens.

    Directory of Open Access Journals (Sweden)

    Bonnie B Blaimer

    Full Text Available Obtaining sequence data from historical museum specimens has been a growing research interest, invigorated by next-generation sequencing methods that allow inputs of highly degraded DNA. We applied a target enrichment and next-generation sequencing protocol to generate ultraconserved elements (UCEs from 51 large carpenter bee specimens (genus Xylocopa, representing 25 species with specimen ages ranging from 2-121 years. We measured the correlation between specimen age and DNA yield (pre- and post-library preparation DNA concentration and several UCE sequence capture statistics (raw read count, UCE reads on target, UCE mean contig length and UCE locus count with linear regression models. We performed piecewise regression to test for specific breakpoints in the relationship of specimen age and DNA yield and sequence capture variables. Additionally, we compared UCE data from newer and older specimens of the same species and reconstructed their phylogeny in order to confirm the validity of our data. We recovered 6-972 UCE loci from samples with pre-library DNA concentrations ranging from 0.06-9.8 ng/μL. All investigated DNA yield and sequence capture variables were significantly but only moderately negatively correlated with specimen age. Specimens of age 20 years or less had significantly higher pre- and post-library concentrations, UCE contig lengths, and locus counts compared to specimens older than 20 years. We found breakpoints in our data indicating a decrease of the initial detrimental effect of specimen age on pre- and post-library DNA concentration and UCE contig length starting around 21-39 years after preservation. Our phylogenetic results confirmed the integrity of our data, giving preliminary insights into relationships within Xylocopa. We consider the effect of additional factors not measured in this study on our age-related sequence capture results, such as DNA fragmentation and preservation method, and discuss the promise of the UCE

  17. Development of European creep crack growth testing code of practice for industrial specimens

    Energy Technology Data Exchange (ETDEWEB)

    Dogan, B.; Nikbin, K. [Imperial College, London (United Kingdom); Petrovski, B. [Technische Univ. Darmstadt (DE). Inst. fuer Werkstoffkunde (IFW)

    2004-07-01

    The integrity and residual life assessment of high temperature components require defects, detected or assumed to exist, through minimum allowable limits of detectable flaws using nondestructive testing methods. It relies on information obtained from the material's mechanical, uniaxial creep, creep crack initiation and growth properties. The information derived from experiments needs to be validated and harmonised following a Code of Practice that data variability between different institutions can be reduced to a minimum. The present paper reports on a Code of Practice (CoP) being prepared within the framework of the partially European Commission funded project CRETE. The novel aspect of the presented CoP is the inclusion of component relevant industrial specimen geometries. It covers testing and analysis of Creep Crack growth (CCG) in metallic materials at elevated temperature using six different cracked geometries that have been validated in. It aims to give advice on testing, measurements and analysis of creep crack growth data for a range of creep brittle to creep ductile materials using component service relevant specimen geometries and sizes. The CoP may be used for material selection criteria and inspection requirements for damage tolerant applications. In quantitative terms, these types of tests can be used to assess the individual and combined effects of metallurgical, fabrication, operating temperature, and loading conditions on creep crack growth life. Further issues will be addressed including material properties, damage and crack growth related constraint effect, stress relaxation and stress-strain fields, residual stresses, partitioning displacement, analysis of elasticcreep, elastic compliance measurements.

  18. Development of European creep crack growth testing code of practice for industrial specimens

    International Nuclear Information System (INIS)

    Dogan, B.; Nikbin, K.; Petrovski, B.

    2004-01-01

    The integrity and residual life assessment of high temperature components require defects, detected or assumed to exist, through minimum allowable limits of detectable flaws using nondestructive testing methods. It relies on information obtained from the material's mechanical, uniaxial creep, creep crack initiation and growth properties. The information derived from experiments needs to be validated and harmonised following a Code of Practice that data variability between different institutions can be reduced to a minimum. The present paper reports on a Code of Practice (CoP) being prepared within the framework of the partially European Commission funded project CRETE. The novel aspect of the presented CoP is the inclusion of component relevant industrial specimen geometries. It covers testing and analysis of Creep Crack growth (CCG) in metallic materials at elevated temperature using six different cracked geometries that have been validated in. It aims to give advice on testing, measurements and analysis of creep crack growth data for a range of creep brittle to creep ductile materials using component service relevant specimen geometries and sizes. The CoP may be used for material selection criteria and inspection requirements for damage tolerant applications. In quantitative terms, these types of tests can be used to assess the individual and combined effects of metallurgical, fabrication, operating temperature, and loading conditions on creep crack growth life. Further issues will be addressed including material properties, damage and crack growth related constraint effect, stress relaxation and stress-strain fields, residual stresses, partitioning displacement, analysis of elastic creep, elastic compliance measurements

  19. On size and geometry effects on the brittle fracture of ferritic and tempered martensitic steels

    Science.gov (United States)

    Odette, G. R.; Chao, B. L.; Lucas, G. E.

    1992-09-01

    A finite element computation of nonsingular crack tip fields was combined with a weakest link statistics model of cleavage fracture. Model predictions for three point bend specimens with various widths and crack depth to width ratios are qualitatively consistent with a number of trends observed in a 12 Cr martensitic stainless steel. The toughness “benefits” of small sizes and shallow cracks are primarily reflected in strain limits rather than net section stress capacities, which is significant to fusion structures subject to large secondary stresses.

  20. What big size you have! Using effect sizes to determine the impact of public health nursing interventions.

    Science.gov (United States)

    Johnson, K E; McMorris, B J; Raynor, L A; Monsen, K A

    2013-01-01

    The Omaha System is a standardized interface terminology that is used extensively by public health nurses in community settings to document interventions and client outcomes. Researchers using Omaha System data to analyze the effectiveness of interventions have typically calculated p-values to determine whether significant client changes occurred between admission and discharge. However, p-values are highly dependent on sample size, making it difficult to distinguish statistically significant changes from clinically meaningful changes. Effect sizes can help identify practical differences but have not yet been applied to Omaha System data. We compared p-values and effect sizes (Cohen's d) for mean differences between admission and discharge for 13 client problems documented in the electronic health records of 1,016 young low-income parents. Client problems were documented anywhere from 6 (Health Care Supervision) to 906 (Caretaking/parenting) times. On a scale from 1 to 5, the mean change needed to yield a large effect size (Cohen's d ≥ 0.80) was approximately 0.60 (range = 0.50 - 1.03) regardless of p-value or sample size (i.e., the number of times a client problem was documented in the electronic health record). Researchers using the Omaha System should report effect sizes to help readers determine which differences are practical and meaningful. Such disclosures will allow for increased recognition of effective interventions.

  1. The Effect of Crumb Rubber Particle Size to the Optimum Binder Content for Open Graded Friction Course

    Directory of Open Access Journals (Sweden)

    Mohd Rasdan Ibrahim

    2014-01-01

    Full Text Available The main objective of this paper is to investigate the relations of rubber size, rubber content, and binder content in determination of optimum binder content for open graded friction course (OGFC. Mix gradation type B as specified in Specification for Porous Asphalt produced by the Road Engineering Association of Malaysia (REAM was used in this study. Marshall specimens were prepared with four different sizes of rubber, namely, 20 mesh size [0.841 mm], 40 mesh [0.42 mm], 80 mesh [0.177 mm], and 100 mesh [0.149 mm] with different concentrations of rubberised bitumen (4%, 8%, and 12% and different percentages of binder content (4%–7%. The appropriate optimum binder content is then selected according to the results of the air voids, binder draindown, and abrasion loss test. Test results found that crumb rubber particle size can affect the optimum binder content for OGFC.

  2. The effectiveness of inking needle core prostate biopsies for preventing patient specimen identification errors: a technique to address Joint Commission patient safety goals in specialty laboratories.

    Science.gov (United States)

    Raff, Lester J; Engel, George; Beck, Kenneth R; O'Brien, Andrea S; Bauer, Meagan E

    2009-02-01

    The elimination or reduction of medical errors has been a main focus of health care enterprises in the United States since the year 2000. Elimination of errors in patient and specimen identification is a key component of this focus and is the number one goal in the Joint Commission's 2008 National Patient Safety Goals Laboratory Services Program. To evaluate the effectiveness of using permanent inks to maintain specimen identity in sequentially submitted prostate needle biopsies. For a 12-month period, a grossing technician stained each prostate core with permanent ink developed for inking of pathology specimens. A different color was used for each patient, with all the prostate cores from all vials for a particular patient inked with the same color. Five colors were used sequentially: green, blue, yellow, orange, and black. The ink was diluted with distilled water to a consistency that allowed application of a thin, uniform coating of ink along the edges of the prostate core. The time required to ink patient specimens comprising different numbers of vials and prostate biopsies was timed. The number and type of inked specimen discrepancies were evaluated. The identified discrepancy rate for prostate biopsy patients was 0.13%. The discrepancy rate in terms of total number of prostate blocks was 0.014%. Diluted inks adhered to biopsy contours throughout tissue processing. The tissue showed no untoward reactions to the inks. Inking did not affect staining (histochemical or immunohistochemical) or pathologic evaluation. On average, inking prostate needle biopsies increases grossing time by 20%. Inking of all prostate core biopsies with colored inks, in sequential order, is an aid in maintaining specimen identity. It is a simple and effective method of addressing Joint Commission patient safety goals by maintaining specimen identity during processing of similar types of gross specimens. This technique may be applicable in other specialty laboratories and high

  3. Prevention of dental erosion of a sports drink by nano-sized hydroxyapatite in situ study.

    Science.gov (United States)

    Min, Ji Hyun; Kwon, Ho Keun; Kim, Baek Il

    2015-01-01

    To evaluate the inhibitory effects of the sports drink containing nano-sized hydroxyapatite (nano-HA) on dental erosion in situ. The study had a single-blind, two-treatment crossover design. The two treatment groups were a control group (CG; Powerade only) and an experimental group (EG; 0.25% wt/vol nano-HA was added to Powerade). Ten subjects wore removable palatal appliances containing bovine enamel specimens. The appliances were immersed in each drink for 10 mins, 4 times a day for 10 days. The tooth surface microhardness (SMH) was tested, and the erosion depth and the morphology of the tooth surface were observed. The data were analysed by repeated measures anova and t-test. Between the baseline and the 10th day, SMH was decreased by 80% in the specimens of the CG (P erosion depth of 12.70 ± 4.66 μm and an irregular tooth surface were observed on the 10th day in the specimens of the CG. No dental erosions, however, was observed in the specimens of the EG. The sports drink containing 0.25% nano-HA was effective in preventing dental erosion in situ. © 2014 BSPD, IAPD and John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Pulsed-voltage atom probe tomography of low conductivity and insulator materials by application of ultrathin metallic coating on nanoscale specimen geometry.

    Science.gov (United States)

    Adineh, Vahid R; Marceau, Ross K W; Chen, Yu; Si, Kae J; Velkov, Tony; Cheng, Wenlong; Li, Jian; Fu, Jing

    2017-10-01

    We present a novel approach for analysis of low-conductivity and insulating materials with conventional pulsed-voltage atom probe tomography (APT), by incorporating an ultrathin metallic coating on focused ion beam prepared needle-shaped specimens. Finite element electrostatic simulations of coated atom probe specimens were performed, which suggest remarkable improvement in uniform voltage distribution and subsequent field evaporation of the insulated samples with a metallic coating of approximately 10nm thickness. Using design of experiment technique, an experimental investigation was performed to study physical vapor deposition coating of needle specimens with end tip radii less than 100nm. The final geometries of the coated APT specimens were characterized with high-resolution scanning electron microscopy and transmission electron microscopy, and an empirical model was proposed to determine the optimal coating thickness for a given specimen size. The optimal coating strategy was applied to APT specimens of resin embedded Au nanospheres. Results demonstrate that the optimal coating strategy allows unique pulsed-voltage atom probe analysis and 3D imaging of biological and insulated samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. The first juvenile specimens of Plateosaurus engelhardti from Frick, Switzerland: isolated neural arches and their implications for developmental plasticity in a basal sauropodomorph

    Directory of Open Access Journals (Sweden)

    Rebecca Hofmann

    2014-07-01

    Full Text Available The dinosaur Plateosaurus engelhardti is the most abundant dinosaur in the Late Triassic of Europe and the best known basal sauropodomorph. Plateosaurus engelhardti was one of the first sauropodomorph dinosaurs to display a large body size. Remains can be found in the Norian stage of the Late Triassic in over 40 localities in Central Europe (France, Germany, and Switzerland and in Greenland. Since the first discovery of P. engelhardti no juvenile specimens of this species had been described in detail. Here we describe the first remains of juvenile individuals, isolated cervical and dorsal neural arches from Switzerland. These were separated postmortem from their respective centra because of unfused neurocentral sutures. However the specimens share the same neural arch morphology found in adults. Morphometric analysis suggests body lengths of the juvenile individuals that is greater than those of most adult specimens. This supports the hypothesis of developmental plasticity in Plateosaurus engelhardti that previously had been based on histological data only. Alternative hypotheses for explaining the poor correlation between ontogenetic stage and size in this taxon are multiple species or sexual morphs with little morphological variance or time-averaging of individuals from populations differing in body size.

  6. 7 CFR 97.8 - Specimen requirements.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Specimen requirements. 97.8 Section 97.8 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... required by the examiner to furnish representative specimens of the variety, or its flower, fruit, or seeds...

  7. Measuring bacterial cells size with AFM

    Directory of Open Access Journals (Sweden)

    Denise Osiro

    2012-03-01

    Full Text Available Atomic Force Microscopy (AFM can be used to obtain high-resolution topographical images of bacteria revealing surface details and cell integrity. During scanning however, the interactions between the AFM probe and the membrane results in distortion of the images. Such distortions or artifacts are the result of geometrical effects related to bacterial cell height, specimen curvature and the AFM probe geometry. The most common artifact in imaging is surface broadening, what can lead to errors in bacterial sizing. Several methods of correction have been proposed to compensate for these artifacts and in this study we describe a simple geometric model for the interaction between the tip (a pyramidal shaped AFM probe and the bacterium (Escherichia coli JM-109 strain to minimize the enlarging effect. Approaches to bacteria immobilization and examples of AFM images analysis are also described.

  8. Estimating minimum polycrystalline aggregate size for macroscopic material homogeneity

    International Nuclear Information System (INIS)

    Kovac, M.; Simonovski, I.; Cizelj, L.

    2002-01-01

    During severe accidents the pressure boundary of reactor coolant system can be subjected to extreme loadings, which might cause failure. Reliable estimation of the extreme deformations can be crucial to determine the consequences of severe accidents. Important drawback of classical continuum mechanics is idealization of inhomogenous microstructure of materials. Classical continuum mechanics therefore cannot predict accurately the differences between measured responses of specimens, which are different in size but geometrical similar (size effect). A numerical approach, which models elastic-plastic behavior on mesoscopic level, is proposed to estimate minimum size of polycrystalline aggregate above which it can be considered macroscopically homogeneous. The main idea is to divide continuum into a set of sub-continua. Analysis of macroscopic element is divided into modeling the random grain structure (using Voronoi tessellation and random orientation of crystal lattice) and calculation of strain/stress field. Finite element method is used to obtain numerical solutions of strain and stress fields. The analysis is limited to 2D models.(author)

  9. A descriptive study of effect-size reporting in research reviews.

    Science.gov (United States)

    Floyd, Judith A

    2017-06-01

    To describe effect-size reporting in research reviews completed in support of evidence-based practice in nursing. Many research reviews report nurses' critical appraisal of level, quality and overall strength of evidence available to address clinical questions. Several studies of research-review quality suggest effect-size information would be useful to include in these reviews, but none focused on reviewers' attention to effect sizes. Descriptive. One hundred and four reviews indexed in CINAHL as systematic reviews and published from July 2012-February 2014 were examined. Papers were required to be peer-reviewed, written in English, contain an abstract and have at least one nurse author. Reviews were excluded if they did not use critical appraisal methods to address evidence of correlation, prediction or effectiveness. Data from remaining papers (N = 73) were extracted by three or more independent coders using a structured coding form and detailed codebook. Data were stored, viewed and analysed using Microsoft Office Excel ® spreadsheet functions. Sixteen percent (n = 12) of the sample contained effect-size information. Of the 12, six included all the effect-size information recommended by APA guidelines. Independent of completeness of reporting, seven contained discussion of effect sizes in the paper, but none included effect-size information in abstracts. Research reviews available to practicing nurses often fail to include information needed to accurately assess how much improvement may result from implementation of evidence-based policies, programs, protocols or practices. Manuscript reviewers are urged to hold authors to APA standards for reporting/discussing effect-size information in both primary research reports and research reviews. © 2016 John Wiley & Sons Ltd.

  10. Developing integrated workflows for the digitisation of herbarium specimens using a modular and scalable approach.

    Science.gov (United States)

    Haston, Elspeth; Cubey, Robert; Pullan, Martin; Atkins, Hannah; Harris, David J

    2012-01-01

    Digitisation programmes in many institutes frequently involve disparate and irregular funding, diverse selection criteria and scope, with different members of staff managing and operating the processes. These factors have influenced the decision at the Royal Botanic Garden Edinburgh to develop an integrated workflow for the digitisation of herbarium specimens which is modular and scalable to enable a single overall workflow to be used for all digitisation projects. This integrated workflow is comprised of three principal elements: a specimen workflow, a data workflow and an image workflow.The specimen workflow is strongly linked to curatorial processes which will impact on the prioritisation, selection and preparation of the specimens. The importance of including a conservation element within the digitisation workflow is highlighted. The data workflow includes the concept of three main categories of collection data: label data, curatorial data and supplementary data. It is shown that each category of data has its own properties which influence the timing of data capture within the workflow. Development of software has been carried out for the rapid capture of curatorial data, and optical character recognition (OCR) software is being used to increase the efficiency of capturing label data and supplementary data. The large number and size of the images has necessitated the inclusion of automated systems within the image workflow.

  11. HER2 testing on core needle biopsy specimens from primary breast cancers: interobserver reproducibility and concordance with surgically resected specimens

    International Nuclear Information System (INIS)

    Tsuda, Hitoshi; Kurosumi, Masafumi; Umemura, Shinobu; Yamamoto, Sohei; Kobayashi, Takayuki; Osamura, Robert Yoshiyuki

    2010-01-01

    Accurate evaluation of human epidermal growth factor receptor type-2 (HER2) status based on core needle biopsy (CNB) specimens is mandatory for identification of patients with primary breast cancer who will benefit from primary systemic therapy with trastuzumab. The aim of the present study was to validate the application of HER2 testing with CNB specimens from primary breast cancers in terms of interobserver reproducibility and comparison with surgically resected specimens. A total of 100 pairs of archival formalin-fixed paraffin-embedded CNB and surgically resected specimens of invasive breast carcinomas were cut into sections. All 100 paired sections were subjected to HER2 testing by immunohistochemistry (IHC) and 27 paired sections were subjected to that by fluorescence in situ hybridization (FISH), the results being evaluated by three and two observers, respectively. Interobserver agreement levels in terms of judgment and the concordance of consensus scores between CNB samples and the corresponding surgically resected specimens were estimated as the percentage agreement and κ statistic. In CNB specimens, the percentage interobserver agreement of HER2 scoring by IHC was 76% (κ = 0.71) for 3 × 3 categories (0-1+ versus 2+ versus 3+) and 90% (κ = 0.80) for 2 × 2 categories (0-2+ versus 3+). These levels were close to the corresponding ones for the surgically resected specimens: 80% (κ = 0.77) for 3 × 3 categories and 92% (κ = 0.88) for 2 × 2 categories. Concordance of consensus for HER2 scores determined by IHC between CNB and the corresponding surgical specimens was 87% (κ = 0.77) for 3 × 3 categories, and 94% (κ = 0.83) for 2 × 2 categories. Among the 13 tumors showing discordance in the mean IHC scores between the CNB and surgical specimens, the results of consensus for FISH results were concordant in 11. The rate of successful FISH analysis and the FISH positivity rate in cases with a HER2 IHC score of 2+ differed among specimens processed at

  12. HER2 testing on core needle biopsy specimens from primary breast cancers: interobserver reproducibility and concordance with surgically resected specimens

    Directory of Open Access Journals (Sweden)

    Yamamoto Sohei

    2010-10-01

    Full Text Available Abstract Background Accurate evaluation of human epidermal growth factor receptor type-2 (HER2 status based on core needle biopsy (CNB specimens is mandatory for identification of patients with primary breast cancer who will benefit from primary systemic therapy with trastuzumab. The aim of the present study was to validate the application of HER2 testing with CNB specimens from primary breast cancers in terms of interobserver reproducibility and comparison with surgically resected specimens. Methods A total of 100 pairs of archival formalin-fixed paraffin-embedded CNB and surgically resected specimens of invasive breast carcinomas were cut into sections. All 100 paired sections were subjected to HER2 testing by immunohistochemistry (IHC and 27 paired sections were subjected to that by fluorescence in situ hybridization (FISH, the results being evaluated by three and two observers, respectively. Interobserver agreement levels in terms of judgment and the concordance of consensus scores between CNB samples and the corresponding surgically resected specimens were estimated as the percentage agreement and κ statistic. Results In CNB specimens, the percentage interobserver agreement of HER2 scoring by IHC was 76% (κ = 0.71 for 3 × 3 categories (0-1+ versus 2+ versus 3+ and 90% (κ = 0.80 for 2 × 2 categories (0-2+ versus 3+. These levels were close to the corresponding ones for the surgically resected specimens: 80% (κ = 0.77 for 3 × 3 categories and 92% (κ = 0.88 for 2 × 2 categories. Concordance of consensus for HER2 scores determined by IHC between CNB and the corresponding surgical specimens was 87% (κ = 0.77 for 3 × 3 categories, and 94% (κ = 0.83 for 2 × 2 categories. Among the 13 tumors showing discordance in the mean IHC scores between the CNB and surgical specimens, the results of consensus for FISH results were concordant in 11. The rate of successful FISH analysis and the FISH positivity rate in cases with a HER2 IHC score of

  13. Agreement for HPV genotyping detection between self-collected specimens on a FTA cartridge and clinician-collected specimens

    Science.gov (United States)

    Guan, YaoYao; Gravitt, Patti E.; Howard, Roslyn; Eby, Yolanda J.; Wang, Shaoming; Li, Belinda; Feng, Changyan; Qiao, You-Lin; Castle, Philip E.

    2016-01-01

    The current method of transporting self-collected cervicovaginal specimen for HPV DNA testing relies on liquid based medium, which is challenging and expensive to transport. A novel, dry storage and transportation device, Whatman indicating FTA™ Elute Cartridge, avoids some of the pitfalls of liquid-based medium. This method has been shown to be comparable to liquid-based collection medium, but relative performance of self-collected (SC) and clinician-collected (CC) samples onto FTA cards has not been reported. The objective of this study is to compare the analytic performance of self- and clinician-collected samples onto FTA cartridges for the detection of carcinogenic HPV using Linear Array. There was a 91% agreement, 69% positive agreement, and kappa of 0.75 between the clinician-collected and self-collected specimens for detection of any carcinogenic HPV genotype. When the HPV results were categorized hierarchically according to cervical cancer risk, there was no difference in the distribution of the HPV results for the clinician- and self-collected specimens (p = 0.7). This study concludes that FTA elute cartridge is a promising method of specimen transport for cervical cancer screening programs considering using self-collected specimen and HPV testing. Larger studies with clinical endpoints are now needed to assess the clinical performance. PMID:23370404

  14. National Aeronautics and Space Administration Biological Specimen Repository

    Science.gov (United States)

    McMonigal, Kathleen A.; Pietrzyk, Robert a.; Johnson, Mary Anne

    2008-01-01

    The National Aeronautics and Space Administration Biological Specimen Repository (Repository) is a storage bank that is used to maintain biological specimens over extended periods of time and under well-controlled conditions. Samples from the International Space Station (ISS), including blood and urine, will be collected, processed and archived during the preflight, inflight and postflight phases of ISS missions. This investigation has been developed to archive biosamples for use as a resource for future space flight related research. The International Space Station (ISS) provides a platform to investigate the effects of microgravity on human physiology prior to lunar and exploration class missions. The storage of crewmember samples from many different ISS flights in a single repository will be a valuable resource with which researchers can study space flight related changes and investigate physiological markers. The development of the National Aeronautics and Space Administration Biological Specimen Repository will allow for the collection, processing, storage, maintenance, and ethical distribution of biosamples to meet goals of scientific and programmatic relevance to the space program. Archiving of the biosamples will provide future research opportunities including investigating patterns of physiological changes, analysis of components unknown at this time or analyses performed by new methodologies.

  15. Molecular Auditing: An Evaluation of Unsuspected Tissue Specimen Misidentification.

    Science.gov (United States)

    Demetrick, Douglas J

    2018-06-18

    Context Specimen misidentification is the most significant error in laboratory medicine, potentially accounting for hundreds of millions of dollars in extra health care expenses and significant morbidity in patient populations in the United States alone. New technology allows the unequivocal documentation of specimen misidentification or contamination; however, the value of this technology currently depends on suspicion of the specimen integrity by a pathologist or other health care worker. Objective To test the hypothesis that there is a detectable incidence of unsuspected tissue specimen misidentification among cases submitted for routine surgical pathology examination. Design To test this hypothesis, we selected specimen pairs that were obtained at different times and/or different hospitals from the same patient, and compared their genotypes using standardized microsatellite markers used commonly for forensic human DNA comparison in order to identify unsuspected mismatches between the specimen pairs as a trial of "molecular auditing." We preferentially selected gastrointestinal, prostate, and skin biopsies because we estimated that these types of specimens had the greatest potential for misidentification. Results Of 972 specimen pairs, 1 showed an unexpected discordant genotype profile, indicating that 1 of the 2 specimens was misidentified. To date, we are unable to identify the etiology of the discordance. Conclusions These results demonstrate that, indeed, there is a low level of unsuspected tissue specimen misidentification, even in an environment with careful adherence to stringent quality assurance practices. This study demonstrates that molecular auditing of random, routine biopsy specimens can identify occult misidentified specimens, and may function as a useful quality indicator.

  16. Effects of crack front curvature on J–R curve testing using clamped SE(T) specimens of homogeneous materials

    International Nuclear Information System (INIS)

    Huang, Yifan; Zhou, Wenxing

    2015-01-01

    Three-dimensional (3D) finite element analyses (FEA) of clamped single-edge tension (SE(T)) specimens are performed to investigate the impact of the crack front curvature on the elastic compliance, compliance rotation correction factor and average J-integral evaluated over the crack front. Specimens with six average crack lengths (i.e. a_a_v_e/W = 0.2–0.7) and three thickness-to-width ratios (i.e. B/W = 0.5, 1 and 2) are analyzed. The curved crack front is assumed to be bowed symmetrically and characterized by a power-law expression with a wide range of curvatures. Several crack front straightness requirements for SE(B) and C(T) specimens specified in BS7448, ISO and ASTM E1820 standards are reviewed. Based on results of the numerical investigation, new crack front straightness criteria for the SE(T) specimen are proposed in the context of the nine-point measurement by using as a criterion that the errors in the estimated compliance and average J values should be no more than five percent. The proposed criteria depend on both a_a_v_e/W and B/W, and are more advantageous than those specified in the BS, ISO and ASTM standards in terms of controlling the differences in J and compliance between the specimens with curved and straight crack fronts. - Highlights: • Investigate the impacts of crack front curvature on the compliance, rotation correction factor and J for SE(T) specimens. • Validate the applicabilities of crack front straightness criteria specified in the seven test standards on SE(T) specimens. • Recommend new crack front straightness criteria for the SE(T) specimen.

  17. An Inset CT Specimen for Evaluating Fracture in Small Samples of Material

    Science.gov (United States)

    Yahyazadehfar, M.; Nazari, A.; Kruzic, J.J.; Quinn, G.D.; Arola, D.

    2013-01-01

    In evaluations on the fracture behavior of hard tissues and many biomaterials, the volume of material available to study is not always sufficient to apply a standard method of practice. In the present study an inset Compact Tension (inset CT) specimen is described, which uses a small cube of material (approximately 2×2×2 mm3) that is molded within a secondary material to form the compact tension geometry. A generalized equation describing the Mode I stress intensity was developed for the specimen using the solutions from a finite element model that was defined over permissible crack lengths, variations in specimen geometry, and a range in elastic properties of the inset and mold materials. A validation of the generalized equation was performed using estimates for the fracture toughness of a commercial dental composite via the “inset CT” specimen and the standard geometry defined by ASTM E399. Results showed that the average fracture toughness obtained from the new specimen (1.23 ± 0.02 MPa•m0.5) was within 2% of that from the standard. Applications of the inset CT specimen are presented for experimental evaluations on the crack growth resistance of dental enamel and root dentin, including their fracture resistance curves. Potential errors in adopting this specimen are then discussed, including the effects of debonding between the inset and molding material on the estimated stress intensity distribution. Results of the investigation show that the inset CT specimen offers a viable approach for studying the fracture behavior of small volumes of structural materials. PMID:24268892

  18. Thermal property testing technique on micro specimen

    International Nuclear Information System (INIS)

    Baba, Tetsuya; Kishimoto, Isao; Taketoshi, Naoyuki

    2000-01-01

    This study aims at establishment of further development on some testing techniques on the nuclear advanced basic research accumulated by the National Research Laboratory of Metrology for ten years. For this purpose, a technology to test heat diffusion ratio and specific heat capacity of less than 3 mm in diameter and 1 mm in thickness of micro specimen and technology to test heat diffusion ratio at micro area of less than 1 mm in area along cross section of less than 10 mm in diameter of column specimen were developed to contribute to common basic technology supporting the nuclear power field. As a result, as an element technology to test heat diffusion ratio and specific heat capacity of the micro specimen, a specimen holding technique stably to hold a micro specimen with 3 mm in diameter could be developed. And, for testing the specific heat capacity by using the laser flush differential calorimetry, a technique to hold two specimen of 5 mm in diameter at their proximities was also developed. In addition, by promoting development of thermal property data base capable of storing thermal property data obtained in this study and with excellent workability in this 1998 fiscal year a data in/out-put program with graphical user interface could be prepared. (G.K.)

  19. Comparative study on Charpy specimen reconstitution techniques

    International Nuclear Information System (INIS)

    Bourdiliau, B.; Decroix, G.-M.; Averty, X.; Wident, P.; Bienvenu, Y.

    2011-01-01

    Highlights: → Welding processes are used to reconstitute previously tested Charpy specimens. → Stud welding is preferred for a quick installation, almost immediately operational. → Friction welding produces better quality welds, but requires a development effort. - Abstract: Reconstitution techniques are often used to allow material from previously fractured Charpy-V specimens to be reused for additional experiments. This paper presents a comparative experimental study of various reconstitution techniques and evaluates the feasibility of these methods for future use in shielded cells. The following techniques were investigated: arc stud welding, 6.0 kW CO 2 continuous wave laser welding, 4.5 kW YAG continuous wave laser welding and friction welding. Subsize Charpy specimens were reconstituted using a 400 W YAG pulsed wave laser. The best result was obtained with arc stud welding; the resilience of the reconstituted specimens and the load-displacement curves agreed well with the reference specimens, and the temperature elevation caused by the welding process was limited to the vicinity of the weld. Good results were also obtained with friction welding; this process led to the best quality welds. Laser welding seems to have affected the central part of the specimens, thus leading to different resilience values and load-displacement curves.

  20. Size effects in lithium ion batteries

    International Nuclear Information System (INIS)

    Yao Hu-Rong; Yin Ya-Xia; Guo Yu-Gao

    2016-01-01

    Size-related properties of novel lithium battery materials, arising from kinetics, thermodynamics, and newly discovered lithium storage mechanisms, are reviewed. Complementary experimental and computational investigations of the use of the size effects to modify electrodes and electrolytes for lithium ion batteries are enumerated and discussed together. Size differences in the materials in lithium ion batteries lead to a variety of exciting phenomena. Smaller-particle materials with highly connective interfaces and reduced diffusion paths exhibit higher rate performance than the corresponding bulk materials. The thermodynamics is also changed by the higher surface energy of smaller particles, affecting, for example, secondary surface reactions, lattice parameter, voltage, and the phase transformation mechanism. Newly discovered lithium storage mechanisms that result in superior storage capacity are also briefly highlighted. (topical review)

  1. Enzymatic detection of formalin-fixed museum specimens for DNA analysis and enzymatic maceration of formalin-fixed specimens

    DEFF Research Database (Denmark)

    Sørensen, Margrethe; Redsted Rasmussen, Arne; Simonsen, Kim Pilkjær

    2016-01-01

    % ethanol. The method was subsequently tested on wild-living preserved specimens and an archived specimen. The protease enzyme used was SavinaseH 16 L, Type EX from Novozymes A/S. The enzymatic screening test demands only simple laboratory equipment. The method is useful for natural history collections...

  2. Determination of Flaw Size from Thermographic Data

    Science.gov (United States)

    Winfree, William P.; Howell, Patricia A.; Zalameda, Joseph N.

    2014-01-01

    Conventional methods for reducing the pulsed thermographic responses of delaminations tend to overestimate the size of the flaw. Since the heat diffuses in the plane parallel to the surface, the resulting temperature profile over the flaw is larger than the flaw. A variational method is presented for reducing the thermographic data to produce an estimated size for the flaw that is much closer to the true size of the flaw. The size is determined from the spatial thermal response of the exterior surface above the flaw and a constraint on the length of the contour surrounding the flaw. The technique is applied to experimental data acquired on a flat bottom hole composite specimen.

  3. Closeout of JOYO-1 Specimen Fabrication Efforts

    International Nuclear Information System (INIS)

    ME Petrichek; JL Bump; RF Luther

    2005-01-01

    Fabrication was well under way for the JOYO biaxial creep and tensile specimens when the NR Space program was canceled. Tubes of FS-85, ASTAR-811C, and T-111 for biaxial creep specimens had been drawn at True Tube (Paso Robles, CA), while tubes of Mo-47.5 Re were being drawn at Rhenium Alloys (Cleveland, OH). The Mo-47.5 Re tubes are now approximately 95% complete. Their fabrication and the quantities produced will be documented at a later date. End cap material for FS-85, ASTAR-811C, and T-111 had been swaged at Pittsburgh Materials Technology, Inc. (PMTI) (Large, PA) and machined at Vangura (Clairton, PA). Cutting of tubes, pickling, annealing, and laser engraving were in process at PMTI. Several biaxial creep specimen sets of FS-85, ASTAR-811C, and T-111 had already been sent to Pacific Northwest National Laboratory (PNNL) for weld development. In addition, tensile specimens of FS-85, ASTAR-811C, T-111, and Mo-47.5 Re had been machined at Kin-Tech (North Huntington, PA). Actual machining of the other specimen types had not been initiated. Flowcharts 1-3 detail the major processing steps each piece of material has experienced. A more detailed description of processing will be provided in a separate document [B-MT(SRME)-51]. Table 1 lists the in-process materials and finished specimens. Also included are current metallurgical condition of these materials and specimens. The available chemical analyses for these alloys at various points in the process are provided in Table 2

  4. Hall measurements and grain-size effects in polycrystalline silicon

    International Nuclear Information System (INIS)

    Ghosh, A.K.; Rose, A.; Maruska, H.P.; Eustace, D.J.; Feng, T.

    1980-01-01

    The effects of grain size on Hall measurements in polycrystalline silicon are analyzed and interpreted, with some modifications, using the model proposed by Bube. This modified model predicts that the measured effective Hall voltage is composed of components originating from the bulk and space-charge regions. For materials with large grain sizes, the carrier concentration is independent of the intergrain boundary barrier, whereas the mobility is dependent on it. However, for small grains, both the carrier density and mobility depend on the barrier. These predictions are consistent with experimental results of mm-size Wacker and μm-size neutron-transmutation-doped polycrystalline silicon

  5. Sea urchins in a high-CO2 world: partitioned effects of body size, ocean warming and acidification on metabolic rate.

    Science.gov (United States)

    Carey, Nicholas; Harianto, Januar; Byrne, Maria

    2016-04-15

    Body size and temperature are the major factors explaining metabolic rate, and the additional factor of pH is a major driver at the biochemical level. These three factors have frequently been found to interact, complicating the formulation of broad models predicting metabolic rates and hence ecological functioning. In this first study of the effects of warming and ocean acidification, and their potential interaction, on metabolic rate across a broad range in body size (two to three orders of magnitude difference in body mass), we addressed the impact of climate change on the sea urchin ITALIC! Heliocidaris erythrogrammain context with climate projections for southeast Australia, an ocean warming hotspot. Urchins were gradually introduced to two temperatures (18 and 23°C) and two pH levels (7.5 and 8.0), at which they were maintained for 2 months. Identical experimental trials separated by several weeks validated the fact that a new physiological steady state had been reached, otherwise known as acclimation. The relationship between body size, temperature and acidification on the metabolic rate of ITALIC! H. erythrogrammawas strikingly stable. Both stressors caused increases in metabolic rate: 20% for temperature and 19% for pH. Combined effects were additive: a 44% increase in metabolism. Body size had a highly stable relationship with metabolic rate regardless of temperature or pH. None of these diverse drivers of metabolism interacted or modulated the effects of the others, highlighting the partitioned nature of how each influences metabolic rate, and the importance of achieving a full acclimation state. Despite these increases in energetic demand there was very limited capacity for compensatory modulating of feeding rate; food consumption increased only in the very smallest specimens, and only in response to temperature, and not pH. Our data show that warming, acidification and body size all substantially affect metabolism and are highly consistent and

  6. The effect of thermal treatment on the mechanical properties of PLLA tubular specimens

    Directory of Open Access Journals (Sweden)

    Arbeiter Daniela

    2016-09-01

    Full Text Available Conventional permanent stent systems for vascular applications are associated with long-term risks, such as restenosis and thrombosis. To overcome these limitations, novel approaches using various biodegradable materials for stent construction have been investigated. In this context, thermal treatment of polymer materials is investigated to adjust the mechanical properties of biodegradable stents. In this work polymeric tubular specimens of biodegradable poly(L-lactide (PLLA were extruded and subjected to a molding process using different temperatures above glass transition temperature TG. Physicochemical properties of the molded samples were analyzed using DSC measurements and uniaxial tensile tests. The molding process resulted in a weakening of the PLLA tubular specimens with a simultaneous increase in the degree of crystallinity (χ.

  7. Design of a cruciform bend specimen for determination of out-of- plane biaxial tensile stress effects on fracture toughness for shallow cracks

    International Nuclear Information System (INIS)

    Bass, B.R.; Bryson, J.W.; Mcafee, W.J.; Pennell, W.E.; Theiss, T.J.

    1993-01-01

    Pressurized-thermal-shock loading in a reactor pressure vessel produces significant positive out-of-plane stresses along the crack front for both circumferential and axial cracks. Experimental evidence, while very limited, seems to indicate that a reduction in toughness is associated with out-of-plane biaxial loading when compared with toughness values obtained under uniaxial conditions. A testing program is described that seeks to determine the effects of out-of-plane biaxial tensile loading on fracture toughness of RPV steels. A cruciform bend specimen that meets specified criteria for the testing pregam is analyzed using three-dimensional elastic-plastic finite-element techniques. These analysis results provide the basis for proposed test conditions that are judged likely to produce a biaxial loading effect in the cruciform bend specimen

  8. Simultaneous specimen and stage cleaning device for analytical electron microscope

    Science.gov (United States)

    Zaluzec, Nestor J.

    1996-01-01

    An improved method and apparatus are provided for cleaning both a specimen stage, a specimen and an interior of an analytical electron microscope (AEM). The apparatus for cleaning a specimen stage and specimen comprising a plasma chamber for containing a gas plasma and an air lock coupled to the plasma chamber for permitting passage of the specimen stage and specimen into the plasma chamber and maintaining an airtight chamber. The specimen stage and specimen are subjected to a reactive plasma gas that is either DC or RF excited. The apparatus can be mounted on the analytical electron microscope (AEM) for cleaning the interior of the microscope.

  9. Effects of sample size on the second magnetization peak in ...

    Indian Academy of Sciences (India)

    the sample size decreases – a result that could be interpreted as a size effect in the order– disorder vortex matter phase transition. However, local magnetic measurements trace this effect to metastable disordered vortex states, revealing the same order–disorder transition induction in samples of different size. Keywords.

  10. Size effects in nanoindentation: an experimental and analytical study

    NARCIS (Netherlands)

    Voyiadjis, G.Z.; Peters, Rick

    2009-01-01

    This work addresses the size effect encountered in nanoindentation experiments. It is generally referred to as the indentation size effect (ISE). Classical descriptions of the ISE show a decrease in hardness for increasing indentation depth. Recently new experiments have shown that after the initial

  11. Does neighborhood size really cause the word length effect?

    Science.gov (United States)

    Guitard, Dominic; Saint-Aubin, Jean; Tehan, Gerald; Tolan, Anne

    2018-02-01

    In short-term serial recall, it is well-known that short words are remembered better than long words. This word length effect has been the cornerstone of the working memory model and a benchmark effect that all models of immediate memory should account for. Currently, there is no consensus as to what determines the word length effect. Jalbert and colleagues (Jalbert, Neath, Bireta, & Surprenant, 2011a; Jalbert, Neath, & Surprenant, 2011b) suggested that neighborhood size is one causal factor. In six experiments we systematically examined their suggestion. In Experiment 1, with an immediate serial recall task, multiple word lengths, and a large pool of words controlled for neighborhood size, the typical word length effect was present. In Experiments 2 and 3, with an order reconstruction task and words with either many or few neighbors, we observed the typical word length effect. In Experiment 4 we tested the hypothesis that the previous abolition of the word length effect when neighborhood size was controlled was due to a confounded factor: frequency of orthographic structure. As predicted, we reversed the word length effect when using short words with less frequent orthographic structures than the long words, as was done in both of Jalbert et al.'s studies. In Experiments 5 and 6, we again observed the typical word length effect, even if we controlled for neighborhood size and frequency of orthographic structure. Overall, the results were not consistent with the predictions of Jalbert et al. and clearly showed a large and reliable word length effect after controlling for neighborhood size.

  12. Size effect in barium titanate powders synthesized by different hydrothermal methods

    International Nuclear Information System (INIS)

    Sun Weian

    2006-01-01

    The size effect in barium titanate (BaTiO 3 ) was investigated both experimentally and theoretically. Tetragonal BaTiO 3 powders with average sizes from 80 to 420 nm were directly prepared by different hydrothermal methods. The tetragonality of the hydrothermal BaTiO 3 decreased with decreasing particle size, which exhibited a dependence on the synthesis method. A phenomenological model for the size effect was proposed to interpret the experimental observations. The influence of the defects, mainly the lattice hydroxyl, on the size effect was investigated to understand the correlation between the size effect and synthesis condition. The permittivities of BaTiO 3 powder at different particle sizes were calculated, which predicted a maximum permittivity of over 16 000 around the room-temperature critical size of ∼70 nm. The prediction was in good accordance with the experimental data reported recently

  13. Agreement for HPV genotyping detection between self-collected specimens on a FTA cartridge and clinician-collected specimens.

    Science.gov (United States)

    Guan, Yaoyao; Gravitt, Patti E; Howard, Roslyn; Eby, Yolanda J; Wang, Shaoming; Li, Belinda; Feng, Changyan; Qiao, You-Lin; Castle, Philip E

    2013-04-01

    The current method of transporting self-collected cervicovaginal specimen for HPV DNA testing relies on liquid based medium, which is challenging and expensive to transport. A novel, dry storage and transportation device, Whatman indicating FTA™ Elute Cartridge, avoids some of the pitfalls of liquid-based medium. This method has been shown to be comparable to liquid-based collection medium, but relative performance of self-collected (SC) and clinician-collected (CC) samples onto FTA cards has not been reported. The objective of this study is to compare the analytic performance of self- and clinician-collected samples onto FTA cartridges for the detection of carcinogenic HPV using Linear Array. There was a 91% agreement, 69% positive agreement, and kappa of 0.75 between the clinician-collected and self-collected specimens for detection of any carcinogenic HPV genotype. When the HPV results were categorized hierarchically according to cervical cancer risk, there was no difference in the distribution of the HPV results for the clinician- and self-collected specimens (p=0.7). This study concludes that FTA elute cartridge is a promising method of specimen transport for cervical cancer screening programs considering using self-collected specimen and HPV testing. Larger studies with clinical endpoints are now needed to assess the clinical performance. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. The characteristics of Chinese orthographic neighborhood size effect for developing readers.

    Directory of Open Access Journals (Sweden)

    Jing Zhao

    Full Text Available Orthographic neighborhood size (N size effect in Chinese character naming has been studied in adults. In the present study, we aimed to explore the developmental characteristics of Chinese N size effect. One hundred and seventeen students (40 from the 3(rd grade with mean age of 9 years; 40 from the 5(th grade with mean age of 11 years; 37 from the 7(th grade with mean age of 13 years were recruited in the study. A naming task of Chinese characters was adopted to elucidate N-size- effect development. Reaction times and error rates were recorded. Results showed that children in the 3(rd grade named characters from large neighborhoods faster than named those from small neighborhoods, revealing a facilitatory N size effect; the 5(th graders showed null N size effect; while the 7(th graders showed an inhibitory N size effect, with longer reaction times for the characters from large neighborhoods than for those from small neighborhoods. The change from facilitation to inhibition of neighborhood size effect across grades suggested the transition from broadly tuned to finely tuned lexical representation in reading development, and the possible inhibition from higher frequency neighbors for higher graders.

  15. Bottom-up and top-down attentional contributions to the size congruity effect.

    Science.gov (United States)

    Sobel, Kenith V; Puri, Amrita M; Faulkenberry, Thomas J

    2016-07-01

    The size congruity effect refers to the interaction between the numerical and physical (i.e., font) sizes of digits in a numerical (or physical) magnitude selection task. Although various accounts of the size congruity effect have attributed this interaction to either an early representational stage or a late decision stage, only Risko, Maloney, and Fugelsang (Attention, Perception, & Psychophysics, 75, 1137-1147, 2013) have asserted a central role for attention. In the present study, we used a visual search paradigm to further study the role of attention in the size congruity effect. In Experiments 1 and 2, we showed that manipulating top-down attention (via the task instructions) had a significant impact on the size congruity effect. The interaction between numerical and physical size was larger for numerical size comparison (Exp. 1) than for physical size comparison (Exp. 2). In the remaining experiments, we boosted the feature salience by using a unique target color (Exp. 3) or by increasing the display density by using three-digit numerals (Exps. 4 and 5). As expected, a color singleton target abolished the size congruity effect. Searching for three-digit targets based on numerical size (Exp. 4) resulted in a large size congruity effect, but search based on physical size (Exp. 5) abolished the effect. Our results reveal a substantial role for top-down attention in the size congruity effect, which we interpreted as support for a shared-decision account.

  16. Replacement/Refurbishment of JSC/NASA POD Specimens

    Science.gov (United States)

    Castner, Willard L.

    2010-01-01

    The NASA Special NDE certification process requires demonstration of NDE capability by test per NASA-STD-5009. This test is performed with fatigue cracked specimens containing very small cracks. The certification test results are usually based on binomial statistics and must meet a 90/95 Probability of Detection (POD). The assumption is that fatigue cracks are tightly closed, difficult to detect, and inspectors and processes passing such a test are well qualified for inspecting NASA fracture critical hardware. The JSC NDE laboratory has what may be the largest inventory that exists of such fatigue cracked NDE demonstration specimens. These specimens were produced by the hundreds in the late 1980s and early 1990s. None have been produced since that time and the condition and usability of the specimens are questionable.

  17. Polystyrene cryostat facilitates testing tensile specimens under liquid nitrogen

    Science.gov (United States)

    Shogan, R. P.; Skalka, R. J.

    1967-01-01

    Lightweight cryostat made of expanded polystyrene reduces eccentricity in a tensile system being tested under liquid nitrogen. The cryostat is attached directly to the tensile system by a special seal, reducing misalignment effects due to cryostat weight, and facilitates viewing and loading of the specimens.

  18. EFFECTIVELY SEARCHING SPECIMEN AND OBSERVATION DATA WITH TOQE, THE THESAURUS OPTIMIZED QUERY EXPANDER

    Directory of Open Access Journals (Sweden)

    Anton Güntsch

    2009-09-01

    Full Text Available Today’s specimen and observation data portals lack a flexible mechanism, able to link up thesaurus-enabled data sources such as taxonomic checklist databases and expand user queries to related terms, significantly enhancing result sets. The TOQE system (Thesaurus Optimized Query Expander is a REST-like XML web-service implemented in Python and designed for this purpose. Acting as an interface between portals and thesauri, TOQE allows the implementation of specialized portal systems with a set of thesauri supporting its specific focus. It is both easy to use for portal programmers and easy to configure for thesaurus database holders who want to expose their system as a service for query expansions. Currently, TOQE is used in four specimen and observation data portals. The documentation is available from http://search.biocase.org/toqe/.

  19. Characterization of the range effect in synthetic aperture radar images of concrete specimens for width estimation

    Science.gov (United States)

    Alzeyadi, Ahmed; Yu, Tzuyang

    2018-03-01

    Nondestructive evaluation (NDE) is an indispensable approach for the sustainability of critical civil infrastructure systems such as bridges and buildings. Recently, microwave/radar sensors are widely used for assessing the condition of concrete structures. Among existing imaging techniques in microwave/radar sensors, synthetic aperture radar (SAR) imaging enables researchers to conduct surface and subsurface inspection of concrete structures in the range-cross-range representation of SAR images. The objective of this paper is to investigate the range effect of concrete specimens in SAR images at various ranges (15 cm, 50 cm, 75 cm, 100 cm, and 200 cm). One concrete panel specimen (water-to-cement ratio = 0.45) of 30-cm-by-30-cm-by-5-cm was manufactured and scanned by a 10 GHz SAR imaging radar sensor inside an anechoic chamber. Scatterers in SAR images representing two corners of the concrete panel were used to estimate the width of the panel. It was found that the range-dependent pattern of corner scatters can be used to predict the width of concrete panels. Also, the maximum SAR amplitude decreases when the range increases. An empirical model was also proposed for width estimation of concrete panels.

  20. Effect size calculation in meta-analyses of psychotherapy outcome research.

    Science.gov (United States)

    Hoyt, William T; Del Re, A C

    2018-05-01

    Meta-analysis of psychotherapy intervention research normally examines differences between treatment groups and some form of comparison group (e.g., wait list control; alternative treatment group). The effect of treatment is normally quantified as a standardized mean difference (SMD). We describe procedures for computing unbiased estimates of the population SMD from sample data (e.g., group Ms and SDs), and provide guidance about a number of complications that may arise related to effect size computation. These complications include (a) incomplete data in research reports; (b) use of baseline data in computing SMDs and estimating the population standard deviation (σ); (c) combining effect size data from studies using different research designs; and (d) appropriate techniques for analysis of data from studies providing multiple estimates of the effect of interest (i.e., dependent effect sizes). Clinical or Methodological Significance of this article: Meta-analysis is a set of techniques for producing valid summaries of existing research. The initial computational step for meta-analyses of research on intervention outcomes involves computing an effect size quantifying the change attributable to the intervention. We discuss common issues in the computation of effect sizes and provide recommended procedures to address them.

  1. Simulation of finite size effects of the fiber bundle model

    Science.gov (United States)

    Hao, Da-Peng; Tang, Gang; Xun, Zhi-Peng; Xia, Hui; Han, Kui

    2018-01-01

    In theory, the macroscopic fracture of materials should correspond with the thermodynamic limit of the fiber bundle model. However, the simulation of a fiber bundle model with an infinite size is unrealistic. To study the finite size effects of the fiber bundle model, fiber bundle models of various size are simulated in detail. The effects of system size on the constitutive behavior, critical stress, maximum avalanche size, avalanche size distribution, and increased step number of external load are explored. The simulation results imply that there is no feature size or cut size for macroscopic mechanical and statistical properties of the model. The constitutive curves near the macroscopic failure for various system size can collapse well with a simple scaling relationship. Simultaneously, the introduction of a simple extrapolation method facilitates the acquisition of more accurate simulation results in a large-limit system, which is better for comparison with theoretical results.

  2. Experimental and Numerical Evaluation of Direct Tension Test for Cylindrical Concrete Specimens

    Directory of Open Access Journals (Sweden)

    Jung J. Kim

    2014-01-01

    Full Text Available Concrete cracking strength can be defined as the tensile strength of concrete subjected to pure tension stress. However, as it is difficult to apply direct tension load to concrete specimens, concrete cracking is usually quantified by the modulus of rupture for flexural members. In this study, a new direct tension test setup for cylindrical specimens (101.6 mm in diameter and 203.2 mm in height similar to those used in compression test is developed. Double steel plates are used to obtain uniform stress distributions. Finite element analysis for the proposed test setup is conducted. The uniformity of the stress distribution along the cylindrical specimen is examined and compared with rectangular cross section. Fuzzy image pattern recognition method is used to assess stress uniformity along the specimen. Moreover, the probability of cracking at different locations along the specimen is evaluated using probabilistic finite element analysis. The experimental and numerical results of the cracking location showed that gravity effect on fresh concrete during setting time might affect the distribution of concrete cracking strength along the height of the structural elements.

  3. Group-size effect on scanning behaviour of Maasai Ostrich Struthio ...

    African Journals Online (AJOL)

    Group-size effect on scanning behaviour of Maasai Ostrich Struthio camelus ... minute) among different group sizes in late 2006 in Serengeti National Park, ... be influenced by factors other than group size, such as body size and habitat type.

  4. Do Effect-Size Measures Measure up?: A Brief Assessment

    Science.gov (United States)

    Onwuegbuzie, Anthony J.; Levin, Joel R.; Leech, Nancy L.

    2003-01-01

    Because of criticisms leveled at statistical hypothesis testing, some researchers have argued that measures of effect size should replace the significance-testing practice. We contend that although effect-size measures have logical appeal, they are also associated with a number of limitations that may result in problematic interpretations of them…

  5. Evaluation on ductile tearing properties of girth weld pipelines using SE(T) and SE(B) specimens

    Energy Technology Data Exchange (ETDEWEB)

    Mathias, Leonardo Luiz Siqueira; Ruggieri, Claudio [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Engenharia Naval e Oceanica

    2012-07-01

    Predictive methodologies aimed at quantifying the impact of defects in oil and gas pipelines play a key role in safety assessment procedures of in-service facilities. Current methodologies for structural integrity assessments advocate the use of geometry dependent resistance curves so that crack-tip constraint in the test specimen closely matches the crack tip constraint for the structural component. Testing standards now under development to measure fracture resistance of pipeline steels (J and CTOD) most often employ single edge notched specimens under tension (SENT) to match a postulated defect in the structural component. This paper presents an investigation of the ductile tearing properties for a girth weld of an API 5L X80 pipeline steel using experimentally measured crack growth resistance curves (J-R curves). Testing of the girth weld pipeline steels employed side-grooved, clamped SE(T) specimen with center-crack weld and side-grooved, three-point bending SE(B) (or SENB) specimens to determine the J-R curves. The methods were compared in terms of geometry, relative crack size and crack-tip constraint, and the results were applied to a case study, to evaluate the degree of conservativeness in defect acceptance criteria. The tests involving SE(B) specimens are usually considered conservative, however, the comparison between this two methods may point an accurate alternative for girth weld assessments, since adequate geometry is adopted to describe accurately the structure's behavior. (author)

  6. Finite size effects in the intermittency analysis of the fragment-size correlations

    International Nuclear Information System (INIS)

    Bozek, P.; Ploszajczak, M.; Tucholski, A.

    1991-01-01

    An influence of the finite size effect on the fragment-size correlations in the nuclear multifragmentation is studied using the method of scaled factorial moments for a 1 - dim percolation model and for a statistical model of the fragmentation process, which for a certain value of a tuning parameter yields the power-law behaviour of the fragment-size distribution. It is shown that the statistical models of this type contain only repulsive correlations due to the conservation laws. The comparison of the results with those obtained in the non-critical 1 - dim percolation and in the 3 - dim percolation at around the critical point is presented. Correlations in the 1 - dim percolation model are analysed analytically and the mechanism of the attractive correlations in 1 - dim and 3 - dim is identified. (author) 30 refs., 7 figs

  7. Digitizing specimens in a small herbarium: A viable workflow for collections working with limited resources1

    Science.gov (United States)

    Harris, Kari M.; Marsico, Travis D.

    2017-01-01

    Premise of the study: Small herbaria represent a significant portion of herbaria in the United States, but many are not digitizing their collections. Methods: At the Arkansas State University Herbarium (STAR), we have created a viable workflow to help small herbaria begin the digitization process, including suggestions for publishing data on the Internet. We calculated hourly rates of each phase of the digitization process. We also mapped accessions at the county level to determine geographic strengths in the collection. Results: All 17,678 accessioned flowering plant specimens at STAR are imaged, databased in Specify, and available electronically on the herbarium’s website. Students imaged the specimens at a mean rate of 145/h. We found differences in databasing rates between the graduate student leading the project (47/h) and undergraduate assistants (25/h). The majority of specimens at STAR were collected within the counties neighboring the institution. Discussion: With this workflow, we estimate that one person can digitize a 20,000-specimen collection in less than 2.5 yr by working only 10 h/wk. Because STAR is a small herbarium with limited resources, the application of the workflow described should assist curators of similar-sized collections as they contemplate and undertake the digitization process. PMID:28439474

  8. Experimental procedure for the characterization of cyclic behavior from very thin plate specimens

    International Nuclear Information System (INIS)

    Maury, A.; Moulin, D.

    1983-01-01

    Many investigators, including those involved in the INTERNATIONAL BENCHMARK PROJECT ON SIMPLIFIED METHODS FOR ELEVATED TEMPERATURE DESIGN AND ANALYSIS - PROBLEM II, have tried to reproduce experimentally observed behavior by inelastic calculations. Unfortunately, the material characteristics used in the computer code were established from monotonic tensile tests performed with specimens extracted from the plate product itself (1.45 mm thick) employed to construct the ratchetting specimen. It now appears that the cyclic behavior of the material is much more relevant to the phenomenon observed. Hence the need to make this kind of characterization. Nevertheless, the practical problem is to produce cyclic stresses, i.e. tensile and compressive stresses, with very thin specimens. The main difficulty is to prevent the buckling effect. A new special device set up for this particular purpose is described here. The solution adopted was to create uniformly distributed alternative pure bending stresses in the thin plate specimen. Bending moments were produced by two end-grips fixed to the specimen, and these grips were mounted on a conventional test-machine which was displacement-controlled. To reduce tensile and compressive membrane stresses inside the specimen, the grips had two parallel axles of rotation. The forces produced by the machine and the displacements of a number of points of the specimen were continuously recorded during the test, so that cyclically stabilized, bending moments could be evaluated easily for each curvature variation imposed. The very first cyclic experimental data obtained, at room temperature, for the material of the sodium test specimen, a 316 type stainless steel, are presented. It may be noted that the simple specimens were very easy to prepare and hence inexpensive. (orig.)

  9. Developing integrated workflows for the digitisation of herbarium specimens using a modular and scalable approach

    Directory of Open Access Journals (Sweden)

    Elspeth Haston

    2012-07-01

    Full Text Available Digitisation programmes in many institutes frequently involve disparate and irregular funding, diverse selection criteria and scope, with different members of staff managing and operating the processes. These factors have influenced the decision at the Royal Botanic Garden Edinburgh to develop an integrated workflow for the digitisation of herbarium specimens which is modular and scalable to enable a single overall workflow to be used for all digitisation projects. This integrated workflow is comprised of three principal elements: a specimen workflow, a data workflow and an image workflow.The specimen workflow is strongly linked to curatorial processes which will impact on the prioritisation, selection and preparation of the specimens. The importance of including a conservation element within the digitisation workflow is highlighted. The data workflow includes the concept of three main categories of collection data: label data, curatorial data and supplementary data. It is shown that each category of data has its own properties which influence the timing of data capture within the workflow. Development of software has been carried out for the rapid capture of curatorial data, and optical character recognition (OCR software is being used to increase the efficiency of capturing label data and supplementary data. The large number and size of the images has necessitated the inclusion of automated systems within the image workflow.

  10. Constraint effects of model coal pillar geometry on its strength

    Energy Technology Data Exchange (ETDEWEB)

    Wahab Khair, A.; Danqing Xu (West Virgina University, Morgantown, WV (United States))

    1994-06-01

    Coal and rock specimens with various diameter/height ratios (D/H) were subjected to compressive test in the laboratory. The deformation and failure characteristics of specimens were studied. The study showed that the D/H ratio of specimens significantly affects the deformation, failure characteristics, and the strength of material. The results provide a better understanding of the mechanism of D/H ratio effect on the strength of materials. The magnitude and mechanism of D/H ratio effect was compared with the effect of confining pressure, and contrasted to size effect. The application of the study to pillar design is discussed. 3 refs., 10 figs.

  11. Efeito do comprimento do corpo-de-prova na velocidade ultra-sônica em madeiras Effect of the size of the specimen on ultrasonic velocity

    Directory of Open Access Journals (Sweden)

    Fabiana Goia Rosa de Oliveira

    2006-02-01

    Full Text Available O presente artigo apresenta um estudo sobre a variação da velocidade ultra-sônica longitudinal em função do comprimento da peça de madeira. As espécies utilizadas foram: pinus caribaea (Pinus caribaea var. caribaea eucalipto citriodora (Eucalyptus citriodora, eucalipto grandis (Eucalyptus grandis e jatobá (Hymenaea sp. Utilizou-se equipamento de ultra-som com transdutores exponenciais de 22 kHz. Foram feitas medições do tempo de propagação das ondas ultra-sônicas, com o comprimento variando de 300 cm a 10 cm e mantendo-se a seção transversal constante de 12 cm x 5 cm. Os resultados apontaram que ocorre variação da velocidade em função da distância percorrida e do comprimento de onda (lambda utilizado. Conclui-se que adequar a freqüência do transdutor com o comprimento da peça é essencial para a determinação correta da velocidade ultra-sônica em madeiras.This paper reports on a study of the variation of ultrasonic velocity with the length of the specimen of pinus caribaea (Pinus caribaea var. caribaea eucalipto citriodora (Eucalyptus citriodora, eucalipto grandis (Eucalyptus grandis and jatobá (Hymenaea sp. Ultrasonic measurements were taken with an experimental apparatus having 22 kHz transducers. Tests were carried out with length from 300 cm to 10 cm and constant cross-section (12 cm x 5 cm. The results showed that velocity of ultrasonic waves is sensitive to changes in the distance between transducers and wavelength (lambda. The adjustment between the frequency of transducer and the length of the specimen is essential in order to obtain correct measurements of ultrasonic velocity in wood.

  12. Size and shape variability in the skull of Myotis nigricans (Schinz, 1821 (Chiroptera: Vespertilionidae from two geographic areas in Brazil

    Directory of Open Access Journals (Sweden)

    R. Bornholdt

    Full Text Available We present a quantitative analysis of sexual dimorphism and geographic variation in the skull of Myotis nigricans (Schinz, 1821 assessed by geometric morphometrics. Differences in size and shape of skulls were investigated using 30 landmarks plotted on two-dimensional images of lateral and ventral views. Results of geometric morphometrics revealed sexual dimorphism in the centroid size of the skull in both views. Females were larger than males. Nevertheless, there was no sexual dimorphism in skull shape of M. nigricans. Geographic variation was detected in size and shape of the skull. South Brazilian specimens were significantly larger than Ceará specimens only in the lateral view. Differences in skull shape were statistically significant in both views: specimens from South Brazil were brevirostri and presented a more expanded skull in the posterior region while Ceará specimens were longirostri and do not present any expansion in the brain case. Ecological factors for these phenomena are discussed in the text.

  13. A non-destructive DNA sampling technique for herbarium specimens.

    Science.gov (United States)

    Shepherd, Lara D

    2017-01-01

    Herbarium specimens are an important source of DNA for plant research but current sampling methods require the removal of material for DNA extraction. This is undesirable for irreplaceable specimens such as rare species or type material. Here I present the first non-destructive sampling method for extracting DNA from herbarium specimens. DNA was successfully retrieved from robust leaves and/or stems of herbarium specimens up to 73 years old.

  14. Miniature tensile test specimens for fusion reactor irradiation studies

    International Nuclear Information System (INIS)

    Klueh, R.L.

    1985-01-01

    Three miniature sheet-type tensile specimens and a miniature rod-type specimen are being used to determine irradiated tensile properties for alloy development for fusion reactors. The tensile properties of type 316 stainless steel were determined with these different specimens, and the results were compared. Reasonably good agreement was observed. However, there were differences that led to recommendations on which specimens are preferred. 4 references, 9 figures, 6 tables

  15. Accelerating plant DNA barcode reference library construction using herbarium specimens: improved experimental techniques.

    Science.gov (United States)

    Xu, Chao; Dong, Wenpan; Shi, Shuo; Cheng, Tao; Li, Changhao; Liu, Yanlei; Wu, Ping; Wu, Hongkun; Gao, Peng; Zhou, Shiliang

    2015-11-01

    A well-covered reference library is crucial for successful identification of species by DNA barcoding. The biggest difficulty in building such a reference library is the lack of materials of organisms. Herbarium collections are potentially an enormous resource of materials. In this study, we demonstrate that it is likely to build such reference libraries using the reconstructed (self-primed PCR amplified) DNA from the herbarium specimens. We used 179 rosaceous specimens to test the effects of DNA reconstruction, 420 randomly sampled specimens to estimate the usable percentage and another 223 specimens of true cherries (Cerasus, Rosaceae) to test the coverage of usable specimens to the species. The barcode rbcLb (the central four-sevenths of rbcL gene) and matK was each amplified in two halves and sequenced on Roche GS 454 FLX+. DNA from the herbarium specimens was typically shorter than 300 bp. DNA reconstruction enabled amplification fragments of 400-500 bp without bringing or inducing any sequence errors. About one-third of specimens in the national herbarium of China (PE) were proven usable after DNA reconstruction. The specimens in PE cover all Chinese true cherry species and 91.5% of vascular species listed in Flora of China. It is very possible to build well-covered reference libraries for DNA barcoding of vascular species in China. As exemplified in this study, DNA reconstruction and DNA-labelled next-generation sequencing can accelerate the construction of local reference libraries. By putting the local reference libraries together, a global library for DNA barcoding becomes closer to reality. © 2015 John Wiley & Sons Ltd.

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

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, Allan

    2005-01-01

    The Charpy impact test is a standard procedure for determining the ductile-brittle transition in welds. The predictions of such tests have been investigated by full three dimensional transient analyses of Charpy V-notch specimens. The material response is characterised by an elastic...... parameters in the weld material differ from those in the base material, and the heat a®ected zone (HAZ) tends to be more brittle than the other material regions. The effect of weld strength undermatch or overmatch is an important issue. Some specimens, for which the notched surface is rotated relative...... to the surface of the test piece, have so complex geometry that only a full 3D analysis is able to account for the interaction of failure in the three different material regions, whereas ther specimens can be approximated in terms of a planar analysis....

  17. Size effects in fcc crystals during the high rate compression test

    International Nuclear Information System (INIS)

    Yaghoobi, Mohammadreza; Voyiadjis, George Z.

    2016-01-01

    The present work studies the different mechanisms of size effects in fcc metallic samples of confined volumes during high rate compression tests using large scale atomistic simulation. Different mechanisms of size effects, including the dislocation starvation, source exhaustion, and dislocation source length effect are investigated for pillars with different sizes. The results show that the controlling mechanisms of size effects depend only on the pillar size and not on the value of applied strain. Dislocation starvation is the governing mechanism for very small pillars, i.e. pillars with diameters less than 30 nm. Increasing the pillar size, the dislocation exhaustion mechanism becomes active and there is no more source-limited activations. Next, the average dislocation source length is obtained and compared for pillars with different sizes. The results show that in the case of high rate deformations, the source length does not depend on the sample size, and the related size effects mechanisms are not active anymore. Also, in the case of high rate deformations, there are no size effects for pristine pillars with the diameters larger than 135 nm. In other words, increasing the strain rate decreases the pillar size at which there is no more size effects in the absence of strain gradient. The governing mechanisms of plastic deformation at high strain rate experiments are also different from those of the quasi-static tests. First, the diameter in which the dislocation nucleation at the free surface becomes the dominant mechanism changes from around 200 nm–30 nm. Next, in the case of the pillars with larger diameters, the plastic deformation is governed by the cross-slip instead of the operation of truncated dislocation sources, which is dominant at slower rates of deformation. In order to study the effects of pillar initial structure on the controlling mechanism of size effects, an initial loading and unloading procedure is conducted on some samples prior to the

  18. Local extinction and recolonization, species effective population size, and modern human origins.

    Science.gov (United States)

    Eller, Elise; Hawks, John; Relethford, John H

    2004-10-01

    A primary objection from a population genetics perspective to a multiregional model of modern human origins is that the model posits a large census size, whereas genetic data suggest a small effective population size. The relationship between census size and effective size is complex, but arguments based on an island model of migration show that if the effective population size reflects the number of breeding individuals and the effects of population subdivision, then an effective population size of 10,000 is inconsistent with the census size of 500,000 to 1,000,000 that has been suggested by archeological evidence. However, these models have ignored the effects of population extinction and recolonization, which increase the expected variance among demes and reduce the inbreeding effective population size. Using models developed for population extinction and recolonization, we show that a large census size consistent with the multiregional model can be reconciled with an effective population size of 10,000, but genetic variation among demes must be high, reflecting low interdeme migration rates and a colonization process that involves a small number of colonists or kin-structured colonization. Ethnographic and archeological evidence is insufficient to determine whether such demographic conditions existed among Pleistocene human populations, and further work needs to be done. More realistic models that incorporate isolation by distance and heterogeneity in extinction rates and effective deme sizes also need to be developed. However, if true, a process of population extinction and recolonization has interesting implications for human demographic history.

  19. Effects of fuel particle size distributions on neutron transport in stochastic media

    International Nuclear Information System (INIS)

    Liang, Chao; Pavlou, Andrew T.; Ji, Wei

    2014-01-01

    Highlights: • Effects of fuel particle size distributions on neutron transport are evaluated. • Neutron channeling is identified as the fundamental reason for the effects. • The effects are noticeable at low packing and low optical thickness systems. • Unit cells of realistic reactor designs are studied for different size particles. • Fuel particle size distribution effects are not negligible in realistic designs. - Abstract: This paper presents a study of the fuel particle size distribution effects on neutron transport in three-dimensional stochastic media. Particle fuel is used in gas-cooled nuclear reactor designs and innovative light water reactor designs loaded with accident tolerant fuel. Due to the design requirements and fuel fabrication limits, the size of fuel particles may not be perfectly constant but instead follows a certain distribution. This brings a fundamental question to the radiation transport computation community: how does the fuel particle size distribution affect the neutron transport in particle fuel systems? To answer this question, size distribution effects and their physical interpretations are investigated by performing a series of neutron transport simulations at different fuel particle size distributions. An eigenvalue problem is simulated in a cylindrical container consisting of fissile fuel particles with five different size distributions: constant, uniform, power, exponential and Gaussian. A total of 15 parametric cases are constructed by altering the fissile particle volume packing fraction and its optical thickness, but keeping the mean chord length of the spherical fuel particle the same at different size distributions. The tallied effective multiplication factor (k eff ) and the spatial distribution of fission power density along axial and radial directions are compared between different size distributions. At low packing fraction and low optical thickness, the size distribution shows a noticeable effect on neutron

  20. 10 CFR 26.165 - Testing split specimens and retesting single specimens.

    Science.gov (United States)

    2010-01-01

    ... (c), as applicable. If the specimen in Bottle A is free of any evidence of drugs or drug metabolites... suitable inquiry conducted under the provisions of § 26.63 or to any other inquiry or investigation... records must be provided to personnel conducting reviews, inquiries into allegations, or audits under the...

  1. Nature of size effects in compact models of field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Torkhov, N. A., E-mail: trkf@mail.ru [Tomsk State University, Tomsk 634050 (Russian Federation); Scientific-Research Institute of Semiconductor Devices, Tomsk 634050 (Russian Federation); Tomsk State University of Control Systems and Radioelectronics, Tomsk 634050 (Russian Federation); Babak, L. I.; Kokolov, A. A.; Salnikov, A. S.; Dobush, I. M. [Tomsk State University of Control Systems and Radioelectronics, Tomsk 634050 (Russian Federation); Novikov, V. A., E-mail: novikovvadim@mail.ru; Ivonin, I. V. [Tomsk State University, Tomsk 634050 (Russian Federation)

    2016-03-07

    Investigations have shown that in the local approximation (for sizes L < 100 μm), AlGaN/GaN high electron mobility transistor (HEMT) structures satisfy to all properties of chaotic systems and can be described in the language of fractal geometry of fractional dimensions. For such objects, values of their electrophysical characteristics depend on the linear sizes of the examined regions, which explain the presence of the so-called size effects—dependences of the electrophysical and instrumental characteristics on the linear sizes of the active elements of semiconductor devices. In the present work, a relationship has been established for the linear model parameters of the equivalent circuit elements of internal transistors with fractal geometry of the heteroepitaxial structure manifested through a dependence of its relative electrophysical characteristics on the linear sizes of the examined surface areas. For the HEMTs, this implies dependences of their relative static (A/mm, mA/V/mm, Ω/mm, etc.) and microwave characteristics (W/mm) on the width d of the sink-source channel and on the number of sections n that leads to a nonlinear dependence of the retrieved parameter values of equivalent circuit elements of linear internal transistor models on n and d. Thus, it has been demonstrated that the size effects in semiconductors determined by the fractal geometry must be taken into account when investigating the properties of semiconductor objects on the levels less than the local approximation limit and designing and manufacturing field effect transistors. In general, the suggested approach allows a complex of problems to be solved on designing, optimizing, and retrieving the parameters of equivalent circuits of linear and nonlinear models of not only field effect transistors but also any arbitrary semiconductor devices with nonlinear instrumental characteristics.

  2. Effect of pretreating technologies on the adhesive strength and anticorrosion property of Zn coated NdFeB specimens

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Pengjie [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Earth-Panda Advance Magnetic Material Co. Ltd., Hefei (China); Anhui Province Key Laboratory of Rare Earth Permanent Magnet Materials, Hefei (China); State Key Laboratory of Rare Earth Permanent Magnet Materials (Earth-Panda Advance Magnetic Material Co., Ltd.), Hefei (China); Xu, Guangqing, E-mail: gqxu1979@hfut.edu.cn [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Liu, Jiaqin [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Yi, Xiaofei [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Earth-Panda Advance Magnetic Material Co. Ltd., Hefei (China); Anhui Province Key Laboratory of Rare Earth Permanent Magnet Materials, Hefei (China); State Key Laboratory of Rare Earth Permanent Magnet Materials (Earth-Panda Advance Magnetic Material Co., Ltd.), Hefei (China); Wu, Yucheng, E-mail: ycwu@hfut.edu.cn [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Chen, JingWu [Earth-Panda Advance Magnetic Material Co. Ltd., Hefei (China); Anhui Province Key Laboratory of Rare Earth Permanent Magnet Materials, Hefei (China); State Key Laboratory of Rare Earth Permanent Magnet Materials (Earth-Panda Advance Magnetic Material Co., Ltd.), Hefei (China)

    2016-02-15

    Graphical abstract: Zn coated NdFeB specimens pretreated with different technologies possess different adhesive strengths and anticorrosion properties. And the combined technology of sandblasting and pickling (5 s) achieves the best comprehensive performance. - Highlights: • Zn coated NdFeB specimens are achieved with different pretreating technologies. • Combined technology possesses the highest adhesive strength. • Combined technology possesses excellent anticorrosion property. - Abstract: Zinc coated NdFeB specimens were prepared with different pretreating technologies, such as polishing, pickling (50 s), sandblasting and combined technology of sandblasting and pickling (5 s). Morphologies of the NdFeB substrates pretreated with different technologies were observed with a scanning electron microscope equipped with an energy dispersive spectrometer and an atomic force microscope. The tensile test was performed to measure the adhesive strength between Zn coating and NdFeB substrate. The self-corrosion behavior of the NdFeB specimen was characterized by potentiodynamic polarization curve. The anticorrosion properties of Zn coated NdFeB specimens were characterized by neutral salt spray tests. The pretreating technologies possess obvious impact on the adhesive strength and anticorrosion property of Zn coated NdFeB specimens. Combined pretreating technology of sandblasting and pickling (5 s) achieves the highest adhesive strength (25.56 MPa) and excellent anticorrosion property (average corrosion current density of 21 μA/cm{sup 2}) in the four pretreating technologies. The impacting mechanisms of the pretreating technology on the adhesive strength and anticorrosion properties are deeply discussed.

  3. Effect of pretreating technologies on the adhesive strength and anticorrosion property of Zn coated NdFeB specimens

    International Nuclear Information System (INIS)

    Zhang, Pengjie; Xu, Guangqing; Liu, Jiaqin; Yi, Xiaofei; Wu, Yucheng; Chen, JingWu

    2016-01-01

    Graphical abstract: Zn coated NdFeB specimens pretreated with different technologies possess different adhesive strengths and anticorrosion properties. And the combined technology of sandblasting and pickling (5 s) achieves the best comprehensive performance. - Highlights: • Zn coated NdFeB specimens are achieved with different pretreating technologies. • Combined technology possesses the highest adhesive strength. • Combined technology possesses excellent anticorrosion property. - Abstract: Zinc coated NdFeB specimens were prepared with different pretreating technologies, such as polishing, pickling (50 s), sandblasting and combined technology of sandblasting and pickling (5 s). Morphologies of the NdFeB substrates pretreated with different technologies were observed with a scanning electron microscope equipped with an energy dispersive spectrometer and an atomic force microscope. The tensile test was performed to measure the adhesive strength between Zn coating and NdFeB substrate. The self-corrosion behavior of the NdFeB specimen was characterized by potentiodynamic polarization curve. The anticorrosion properties of Zn coated NdFeB specimens were characterized by neutral salt spray tests. The pretreating technologies possess obvious impact on the adhesive strength and anticorrosion property of Zn coated NdFeB specimens. Combined pretreating technology of sandblasting and pickling (5 s) achieves the highest adhesive strength (25.56 MPa) and excellent anticorrosion property (average corrosion current density of 21 μA/cm 2 ) in the four pretreating technologies. The impacting mechanisms of the pretreating technology on the adhesive strength and anticorrosion properties are deeply discussed.

  4. Handling of biological specimens for electron microscopy

    International Nuclear Information System (INIS)

    Bullock, G.

    1987-01-01

    There are many different aspects of specimen preparation procedure which need to be considered in order to achieve good results. Whether using the scanning or transmission microscope, the initial handling procedures are very similar and are selected for the information required. Handling procedures and techniques described are: structural preservation; immuno-and histo-chemistry; x-ray microanalysis and autoradiography; dehydration and embedding; mounting and coating specimens for scanning electron microscopy; and sectioning of resin embedded material. With attention to detail and careful choice of the best available technique, excellent results should be obtainable whatever the specimen. 6 refs

  5. Finite element simulations of electrostatic dopant potentials in thin semiconductor specimens for electron holography.

    Science.gov (United States)

    Somodi, P K; Twitchett-Harrison, A C; Midgley, P A; Kardynał, B E; Barnes, C H W; Dunin-Borkowski, R E

    2013-11-01

    Two-dimensional finite element simulations of electrostatic dopant potentials in parallel-sided semiconductor specimens that contain p-n junctions are used to assess the effect of the electrical state of the surface of a thin specimen on projected potentials measured using off-axis electron holography in the transmission electron microscope. For a specimen that is constrained to have an equipotential surface, the simulations show that the step in the projected potential across a p-n junction is always lower than would be predicted from the properties of the bulk device, but is relatively insensitive to the value of the surface state energy, especially for thicker specimens and higher dopant concentrations. The depletion width measured from the projected potential, however, has a complicated dependence on specimen thickness. The results of the simulations are of broader interest for understanding the influence of surfaces and interfaces on electrostatic potentials in nanoscale semiconductor devices. © 2013 Elsevier B.V. All rights reserved.

  6. Computation of Effect Size for Moderating Effects of Categorical Variables in Multiple Regression

    Science.gov (United States)

    Aguinis, Herman; Pierce, Charles A.

    2006-01-01

    The computation and reporting of effect size estimates is becoming the norm in many journals in psychology and related disciplines. Despite the increased importance of effect sizes, researchers may not report them or may report inaccurate values because of a lack of appropriate computational tools. For instance, Pierce, Block, and Aguinis (2004)…

  7. Effects of Seed Size on Germination and Early Morphorlogical and ...

    African Journals Online (AJOL)

    Effects of Seed Size on Germination and Early Morphorlogical and Physiological Characteristics of Gmelina Arborea , Roxb. ... African Research Review ... They were grouped into 3 categories as large seed size (LSS), medium seed size ...

  8. Elastic-plastic analysis of the SS-3 tensile specimen

    International Nuclear Information System (INIS)

    Majumdar, S.

    1998-01-01

    Tensile tests of most irradiated specimens of vanadium alloys are conducted using the miniature SS-3 specimen which is not ASTM approved. Detailed elastic-plastic finite element analysis of the specimen was conducted to show that, as long as the ultimate to yield strength ratio is less than or equal to 1.25 (which is satisfied by many irradiated materials), the stress-plastic strain curve obtained by using such a specimen is representative of the true material behavior

  9. Progress Report on Alloy 617 Notched Specimen Testing

    Energy Technology Data Exchange (ETDEWEB)

    McMurtrey, Michael David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Wright, Richard Neil [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lillo, Thomas Martin [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-08-01

    Creep behavior of Alloy 617 has been extensively characterized to support the development of a draft Code Case to qualify Alloy 617 in Section III division 5 of the ASME Boiler and Pressure Vessel Code. This will allow use of Alloy 617 in construction of nuclear reactor components at elevated temperatures and longer periods of time (up to 950°C and 100,000 hours). Prior to actual use, additional concerns not considered in the ASME code need to be addressed. Code Cases are based largely on uniaxial testing of smooth gage specimens. In service conditions, components will generally be under multi axial loading. There is also the concern of the behavior at discontinuities, such as threaded components. To address the concerns of multi axial creep behavior and at geometric discontinuities, notched specimens have been designed to create conditions representative of the states that service components experience. Two general notch geometries have been used for these series of tests: U notch and V notch specimens. The notches produce a tri axial stress state, though not uniform across the specimen. Characterization of the creep behavior of the U notch specimens and the creep rupture behavior of the V notch specimens provides a good approximation of the behavior expected of actual components. Preliminary testing and analysis have been completed and are reported in this document. This includes results from V notch specimens tested at 900°C and 800°C. Failure occurred in the smooth gage section of the specimen rather than at the root of the notch, though some damage was present at the root of the notch, where initial stress was highest. This indicates notch strengthening behavior in this material at these temperatures.

  10. Scanning transmission ion micro-tomography (STIM-T) of biological specimens

    International Nuclear Information System (INIS)

    Schwertner, Michael; Sakellariou, Arthur; Reinert, Tilo; Butz, Tilman

    2006-01-01

    Computed tomography (CT) was applied to sets of Scanning Transmission Ion Microscopy (STIM) projections recorded at the LIPSION ion beam laboratory (Leipzig) in order to visualize the 3D-mass distribution in several specimens. Examples for a test structure (copper grid) and for biological specimens (cartilage cells, cygospore) are shown. Scanning Transmission Micro-Tomography (STIM-T) at a resolution of 260 nm was demonstrated for the first time. Sub-micron features of the Cu-grid specimen were verified by scanning electron microscopy. The ion energy loss measured during a STIM-T experiment is related to the mass density of the specimen. Typically, biological specimens can be analysed without staining. Only shock freezing and freeze-drying is required to preserve the ultra-structure of the specimen. The radiation damage to the specimen during the experiment can be neglected. This is an advantage compared to other techniques like X-ray micro-tomography. At present, the spatial resolution is limited by beam position fluctuations and specimen vibrations

  11. Investigation into the effects of steel wire rope specimen length on breaking force

    CSIR Research Space (South Africa)

    O'Brien, TM

    2004-03-01

    Full Text Available (2000). The methodology employed was to test different length of triangular strand and non-spin rope to destruction, and to evaluate these results against SABS 0293:1996. For each rope construction, specimens were prepared both with and without cut wires...

  12. Size effect of the elastic modulus of rectangular nanobeams: Surface elasticity effect

    International Nuclear Information System (INIS)

    Yao Hai-Yan; Fan Wen-Liang; Yun Guo-Hong

    2013-01-01

    The size-dependent elastic property of rectangular nanobeams (nanowires or nanoplates) induced by the surface elasticity effect is investigated by using a developed modified core-shell model. The effect of surface elasticity on the elastic modulus of nanobeams can be characterized by two surface related parameters, i.e., inhomogeneous degree constant and surface layer thickness. The analytical results show that the elastic modulus of the rectangular nanobeam exhibits a distinct size effect when its characteristic size reduces below 100 nm. It is also found that the theoretical results calculated by a modified core-shell model have more obvious advantages than those by other models (core-shell model and core-surface model) by comparing them with relevant experimental measurements and computational results, especially when the dimensions of nanostructures reduce to a few tens of nanometers. (condensed matter: structural, mechanical, and thermal properties)

  13. Final Report: Posttest Analysis of Omega II Optical Specimens

    International Nuclear Information System (INIS)

    Newlander, C D; Fisher, J H

    2007-01-01

    Preliminary posttest analyses have been completed on optical specimens exposed during the Omega II test series conducted on 14 July 2006. The Omega Facility, located at the Laboratory for Laser Energetics (LLE) at the University of Rochester was used to produce X-ray environments through the interaction of intense pulsed laser radiation upon germanium-loaded silica aerogels. The optical specimen testing was supported by GH Systems through experiment design, pre- and post-test analyses, specimen acquisition, and overall technical experience. The test specimens were fabricated and characterized by Surface Optics Corporation (SOC), San Diego, CA and were simple protected gold coatings on silica substrates. Six test specimens were exposed, five filtered with thin beryllium foil filters, and one unfiltered which was exposed directly to the raw environment. The experimental objectives were: (1) demonstrate that tests of optical specimens could be performed at the Omega facility; (2) evaluate the use and survivability of beryllium foil filters as a function of thickness; (3) obtain damage data on optical specimens which ranged from no damage to damage; (4) correlate existing thermal response models with the damage data; (5) evaluate the use of the direct raw environment upon the specimen response and the ability/desirability to conduct sensitive optical specimen tests using the raw environment; and (6) initiate the development of a protocol for performing optical coatings/mirror tests. This report documents the activities performed by GH Systems in evaluating and using the environments provided by LLNL, the PUFFTFT analyses performed using those environments, and the calculated results compared to the observed and measured posttest data

  14. Effect of particle size on thermal decomposition of alkali metal picrates

    International Nuclear Information System (INIS)

    Liu, Rui; Zhang, Tonglai; Yang, Li; Zhou, Zunning

    2014-01-01

    Graphical abstract: The smaller-sized picrate has greater gas emission than do its larger counterpart. The small size effect reduces the thermal decomposition activation energy, accelerates the reaction rate, and promotes the reaction activity. - Highlights: • Picrates were prepared into three micron sizes by microemulsion synthesis. • Thermal decomposition kinetics and thermodynamics were studied by DPTA and DSC. • Smaller-sized picrate has higher activity and faster reaction rate. • Particle size effect on thermal decomposition kinetics and thermodynamics was revealed. - Abstract: Three alkali metal picrates, KPA, RbPA and CsPA, were prepared into three micron sizes by microemulsion synthesis, and their thermal decomposition behaviors were investigated by DPTA at different temperatures and by DSC at different heating rates. The smaller-sized picrate has greater gas emission and smaller kinetic and thermodynamic parameters than do its larger counterpart. It can be attributed to the decreasing particle size which leads to the high surface energy, the fast mass and heat transfer, and the increasing active sites on the reaction interface. The small size effect and surface effect cause the autocatalysis which reduces the activation energy and promotes the reaction activity. The particle size does not affect the reaction mechanism. However, the picrates with different central alkali metals exhibit different reaction mechanisms even though they are of the same size. This is because the central metal determines the bond energy and consequently affects the stability of picrate

  15. Effect of particle size on thermal decomposition of alkali metal picrates

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Rui; Zhang, Tonglai, E-mail: ztlbit@bit.edu.cn; Yang, Li; Zhou, Zunning

    2014-05-01

    Graphical abstract: The smaller-sized picrate has greater gas emission than do its larger counterpart. The small size effect reduces the thermal decomposition activation energy, accelerates the reaction rate, and promotes the reaction activity. - Highlights: • Picrates were prepared into three micron sizes by microemulsion synthesis. • Thermal decomposition kinetics and thermodynamics were studied by DPTA and DSC. • Smaller-sized picrate has higher activity and faster reaction rate. • Particle size effect on thermal decomposition kinetics and thermodynamics was revealed. - Abstract: Three alkali metal picrates, KPA, RbPA and CsPA, were prepared into three micron sizes by microemulsion synthesis, and their thermal decomposition behaviors were investigated by DPTA at different temperatures and by DSC at different heating rates. The smaller-sized picrate has greater gas emission and smaller kinetic and thermodynamic parameters than do its larger counterpart. It can be attributed to the decreasing particle size which leads to the high surface energy, the fast mass and heat transfer, and the increasing active sites on the reaction interface. The small size effect and surface effect cause the autocatalysis which reduces the activation energy and promotes the reaction activity. The particle size does not affect the reaction mechanism. However, the picrates with different central alkali metals exhibit different reaction mechanisms even though they are of the same size. This is because the central metal determines the bond energy and consequently affects the stability of picrate.

  16. Core size effects on safety performances of LMRs

    Energy Technology Data Exchange (ETDEWEB)

    Na, Byung Chan; Hahn, Do Hee [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    An oxide fuel small size core (1200 MWt) was analyzed in comparison with a large size core (3600 MWt) in order to evaluate the size effects on transient safety performances of liquid-metal reactors (LMRs). In the first part of the study, main static safety parameters (i.e., Doppler coefficient, sodium void effect, etc.) of the two cores were characterized, and the second part of the study was focused on the dynamic behavior of the cores in two representative transient events: the unprotected loss-of-flow (ULOF) and the unprotected transient overpower (UTOP). Margins to fuel melting and sodium boiling have been evaluated for these representative transients. Results show that the small core has a generally better or equivalent level of safety performances during these events. 6 refs., 4 figs., 2 tabs. (Author)

  17. Core size effects on safety performances of LMRs

    Energy Technology Data Exchange (ETDEWEB)

    Na, Byung Chan; Hahn, Do Hee [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    An oxide fuel small size core (1200 MWt) was analyzed in comparison with a large size core (3600 MWt) in order to evaluate the size effects on transient safety performances of liquid-metal reactors (LMRs). In the first part of the study, main static safety parameters (i.e., Doppler coefficient, sodium void effect, etc.) of the two cores were characterized, and the second part of the study was focused on the dynamic behavior of the cores in two representative transient events: the unprotected loss-of-flow (ULOF) and the unprotected transient overpower (UTOP). Margins to fuel melting and sodium boiling have been evaluated for these representative transients. Results show that the small core has a generally better or equivalent level of safety performances during these events. 6 refs., 4 figs., 2 tabs. (Author)

  18. Nanoindentation study of size effect and loading rate effect on mechanical properties of a thin film metallic glass Cu49.3Zr50.7

    International Nuclear Information System (INIS)

    Pang Jianjun; Tan Mingjen; Liew, K.M.; Shearwood, Christopher

    2012-01-01

    A binary metallic glass (MG) Cu 49.3 Zr 50.7 in the form of thin film was successfully grown on a Si (1 0 0) substrate by magnetron sputtering. The mechanical properties, specifically, hardness and modulus at various peak loads and loading rates were characterized through instrumented nanoindentation. Unlike other metallic glasses showing an indentation size effect (ISE), the composition of this study does not have an ISE, which is phenomenologically the result of the negligible length scale according to the strain gradient plasticity model. The proportional specimen resistance model is applicable to the load-displacement behaviors and suggests that the frictional effect is too small to contribute to the ISE. The occurrence of plasticity depends on loading rates and can be delayed so that the displacement during the load holding segment increases logarithmically. In addition, the hardness and modulus are both dependent on the loading rates as well, i.e., they increase as the loading rate increases up to 0.1 mN/s and then hold constant, which is independent of creep time (≤100 s). These loading-rate-dependent behaviors are interpreted as the result of viscoelastic effect rather than free volume kinetics.

  19. Size effects in PbTiO3 nanocrystals: Effect of particle size on spontaneous polarization and strains

    Science.gov (United States)

    Akdogan, E. K.; Rawn, C. J.; Porter, W. D.; Payzant, E. A.; Safari, A.

    2005-04-01

    The spontaneous polarization (Ps) and spontaneous strains (xi) in mechanically unclamped and surface charge compensated PbTiO3 nanocrystals were determined as a function of particle size in the range <150nm by differential scanning calorimetry and x-ray powder diffraction, respectively. Significant deviations from bulk order parameters (P,xi) have been observed as the particle size decreased below ˜100nm. The critical size (rc) below which the ferroelectric tetragonal phase transforms to the paraelectric cubic phase was determined as ˜15nm. The depression in transition temperature with particle size is 14 °C at 28 nm. No change in the order of m3m →4mm ferrodistortive phase transition is observed. A simple analysis showed that ΔHtr/(kBT )˜103 at 25 °C for r =16nm, indicating that the stabilization of the cubic phase at rc cannot be linked to an instability in dipolar ordering due to thermal agitations. Comparison of the spontaneous volumetric strains with the strain induced by surface stress indicated that the effect of surface stress on ferroelectric phase stability was negligible. Anomalies in electrostrictive properties were determined for r →rc. The observed size dependence of PS is attributed to the reduced extent of long-range dipole-dipole interactions that arise due to the changes in bonding characteristics of ions with decreasing particle size in the perovskite lattice, in conformity with a recent study by Tsunekawa et al. [Phys. Rev. Lett. 85 (16), 4340 (2000)].

  20. Effects of tensile test parameters on the mechanical properties of a bimodal Al–Mg alloy

    International Nuclear Information System (INIS)

    Magee, Andrew; Ladani, Leila; Topping, Troy D.; Lavernia, Enrique J.

    2012-01-01

    The properties of aluminum alloy (AA) 5083 are shown to be significantly improved by grain size reduction through cryomilling and the incorporation of unmilled Al particles into the material, creating a bimodal grain size distribution consisting of coarse grains in a nanocrystalline matrix. To provide insight into the mechanical behavior and ultimately facilitate engineering applications, the present study reports on the effects of coarse grain ratio, anisotropy, strain rate and specimen size on the elastic–plastic behavior of bimodal AA 5083 evaluated in uniaxial tension tests using a full-factorial experiment design. To determine the governing failure mechanisms under different testing conditions, the specimens’ failure surfaces were analyzed using optical and electron microscopy. The results of the tests were found to conform to Joshi’s plasticity model. Significant anisotropy effects were observed, in a drastic reduction in strength and ductility, when tension was applied perpendicular (transverse) to the direction of extrusion. These specimens also exhibited a smooth, flat fracture surface morphology with a significantly different surface texture than specimens tested in the axial direction. It was found that decreasing specimen thickness and strain rate served to increase both the strength and ductility of the material. The failure surface morphology was found to differ between specimens of different thicknesses.

  1. Determination of a cohesive law for delamination modelling - Accounting for variation in crack opening and stress state across the test specimen width

    DEFF Research Database (Denmark)

    Joki, R. K.; Grytten, F.; Hayman, Brian

    2016-01-01

    by differentiating the fracture resistance with respect to opening displacement at the initial location of the crack tip, measured at the specimen edge. 2) Extend the bridging law to a cohesive law by accounting for crack tip fracture energy. 3) Fine-tune the cohesive law through an iterative modelling approach so......The cohesive law for Mode I delamination in glass fibre Non-Crimped Fabric reinforced vinylester is determined for use in finite element models. The cohesive law is derived from a delamination test based on DCB specimens loaded with pure bending moments taking into account the presence of large...... that the changing state of stress and deformation across the width of the test specimen is taken into account. The changing state of stress and deformation across the specimen width is shown to be significant for small openings (small fracture process zone size). This will also be important for the initial part...

  2. R2 effect-size measures for mediation analysis.

    Science.gov (United States)

    Fairchild, Amanda J; Mackinnon, David P; Taborga, Marcia P; Taylor, Aaron B

    2009-05-01

    R(2) effect-size measures are presented to assess variance accounted for in mediation models. The measures offer a means to evaluate both component paths and the overall mediated effect in mediation models. Statistical simulation results indicate acceptable bias across varying parameter and sample-size combinations. The measures are applied to a real-world example using data from a team-based health promotion program to improve the nutrition and exercise habits of firefighters. SAS and SPSS computer code are also provided for researchers to compute the measures in their own data.

  3. R2 effect-size measures for mediation analysis

    Science.gov (United States)

    Fairchild, Amanda J.; MacKinnon, David P.; Taborga, Marcia P.; Taylor, Aaron B.

    2010-01-01

    R2 effect-size measures are presented to assess variance accounted for in mediation models. The measures offer a means to evaluate both component paths and the overall mediated effect in mediation models. Statistical simulation results indicate acceptable bias across varying parameter and sample-size combinations. The measures are applied to a real-world example using data from a team-based health promotion program to improve the nutrition and exercise habits of firefighters. SAS and SPSS computer code are also provided for researchers to compute the measures in their own data. PMID:19363189

  4. Tension test system for irradiated small specimens operated by remote control

    International Nuclear Information System (INIS)

    Okada, Akira

    1993-01-01

    A robot-based tension test system has been developed to aid in the mechanical testing of highly radioactive specimens. This system reduces radiation hazards from specimens and allows for the uniform precision of testing results independent of experimenters' skills. The robot system is designed to accommodate a miniaturized tension specimen with a gage section 5.5 by 1.2 mm, with a total length and width of 12.5 and 2.3 mm, respectively, and thickness of about 0.2 mm. The system is composed of a manipulating robot, a vibrational-type specimen feeder, a rotating-type specimen tray, a specimen observation system, a simulated tension text fixture, and a microcomputer for controlling the system. This system accomplishes specimen arrangement in the specimen tray, specimen transportation and loading to the test fixture and testing, and removal of the broken specimen from the fixture. These procedures are performed quickly, safely, and with uniform testing precision by computer control remotely by an unskilled experimenter

  5. Performance of next-generation sequencing on small tumor specimens and/or low tumor content samples using a commercially available platform.

    Directory of Open Access Journals (Sweden)

    Scott Morris

    Full Text Available Next generation sequencing tests (NGS are usually performed on relatively small core biopsy or fine needle aspiration (FNA samples. Data is limited on what amount of tumor by volume or minimum number of FNA passes are needed to yield sufficient material for running NGS. We sought to identify the amount of tumor for running the PCDx NGS platform.2,723 consecutive tumor tissues of all cancer types were queried and reviewed for inclusion. Information on tumor volume, success of performing NGS, and results of NGS were compiled. Assessment of sequence analysis, mutation calling and sensitivity, quality control, drug associations, and data aggregation and analysis were performed.6.4% of samples were rejected from all testing due to insufficient tumor quantity. The number of genes with insufficient sensitivity make definitive mutation calls increased as the percentage of tumor decreased, reaching statistical significance below 5% tumor content. The number of drug associations also decreased with a lower percentage of tumor, but this difference only became significant between 1-3%. The number of drug associations did decrease with smaller tissue size as expected. Neither specimen size or percentage of tumor affected the ability to pass mRNA quality control. A tumor area of 10 mm2 provides a good margin of error for specimens to yield adequate drug association results.Specimen suitability remains a major obstacle to clinical NGS testing. We determined that PCR-based library creation methods allow the use of smaller specimens, and those with a lower percentage of tumor cells to be run on the PCDx NGS platform.

  6. An Upgrade Pinning Block: A Mechanical Practical Aid for Fast Labelling of the Insect Specimens.

    Science.gov (United States)

    Ghafouri Moghaddam, Mohammad Hossein; Ghafouri Moghaddam, Mostafa; Rakhshani, Ehsan; Mokhtari, Azizollah

    2017-01-01

    A new mechanical innovation is described to deal with standard labelling of dried specimens on triangular cards and/or pinned specimens in personal and public collections. It works quickly, precisely, and easily and is very useful for maintaining label uniformity in collections. The tools accurately sets the position of labels in the shortest possible time. This tools has advantages including rapid processing, cost effectiveness, light weight, and high accuracy, compared to conventional methods. It is fully customisable, compact, and does not require specialist equipment to assemble. Conventional methods generally require locating holes on the pinning block surface when labelling with a resulting risk to damage of the specimens. Insects of different orders can be labelled by this simple and effective tool.

  7. Selection dramatically reduces effective population size in HIV-1 infection

    Directory of Open Access Journals (Sweden)

    Mittler John E

    2008-05-01

    Full Text Available Abstract Background In HIV-1 evolution, a 100–100,000 fold discrepancy between census size and effective population size (Ne has been noted. Although it is well known that selection can reduce Ne, high in vivo mutation and recombination rates complicate attempts to quantify the effects of selection on HIV-1 effective size. Results We use the inbreeding coefficient and the variance in allele frequency at a linked neutral locus to estimate the reduction in Ne due to selection in the presence of mutation and recombination. With biologically realistic mutation rates, the reduction in Ne due to selection is determined by the strength of selection, i.e., the stronger the selection, the greater the reduction. However, the dependence of Ne on selection can break down if recombination rates are very high (e.g., r ≥ 0.1. With biologically likely recombination rates, our model suggests that recurrent selective sweeps similar to those observed in vivo can reduce within-host HIV-1 effective population sizes by a factor of 300 or more. Conclusion Although other factors, such as unequal viral reproduction rates and limited migration between tissue compartments contribute to reductions in Ne, our model suggests that recurrent selection plays a significant role in reducing HIV-1 effective population sizes in vivo.

  8. Ultrasonic attenuation as a function of heat treatment and grain size in 79Ni--6Mo--15Fe alloy

    International Nuclear Information System (INIS)

    Gieske, J.H.

    1978-03-01

    A pulse echo ultrasonic technique was used to measure the attenuation coefficient for 79Ni-6Mo-15Fe alloy specimens. The attenuation coefficient was determined using a 25 MHz ultrasonic transducer for specimens which had undergone different time-temperature heat treatments. The ultrasonic attenuation data versus heat treat time was used to assess grain size growth in the specimens

  9. Effect of particle size on the glass transition.

    Science.gov (United States)

    Larsen, Ryan J; Zukoski, Charles F

    2011-05-01

    The glass transition temperature of a broad class of molecules is shown to depend on molecular size. This dependency results from the size dependence of the pair potential. A generalized equation of state is used to estimate how the volume fraction at the glass transition depends on the size of the molecule, for rigid molecule glass-formers. The model shows that at a given pressure and temperature there is a size-induced glass transition: For molecules larger than a critical size, the volume fraction required to support the effective pressure due to particle attractions is above that which characterizes the glassy state. This observation establishes the boundary between nanoparticles, which exist in liquid form only as dispersions in low molecular weight solvents and large molecules which form liquids that have viscosities below those characterized by the glassy state.

  10. Dynamic fracture analysis of a transverse wedge-loaded compact specimen

    International Nuclear Information System (INIS)

    Urabe, Yoshio; Funada, Tatsuo; Hojo, Kiminobu; Baba, Kinji

    1986-01-01

    The J-integral method cannot be applied to the elastic plastic dynamic crack propagation, because unloading and inertia force may take place. From this point of view dynamic elastic plastic scheme using J-integral is developed. Using this dynamic finite element program an MRL type specimen is analyzed. As the result, the property of path-independence of the J-integral under the existence of inertia force and unloading is confirmed. Dynamic effects are considerably small in the MRL type specimen. Also the influence of plastic zone on the crack arrest toughness is shown. Finally the present result is compared with the request of ASTM 2nd round robin test program for crack arrest toughness. (orig.)

  11. Cytogenetic and molecular characterization of Speothos venaticus specimens - doi: 10.4025/actascibiolsci.v32i4.6775 Cytogenetic and molecular characterization of Speothos venaticus specimens - doi: 10.4025/actascibiolsci.v32i4.6775

    Directory of Open Access Journals (Sweden)

    Lígia Souza Lima Silveira da Mota

    2010-11-01

    Full Text Available The bush dog (Speothos venaticus is a South American canid, included in the IBAMA (Brazilian Institute of Environment and Renewable Natural Resources official list of animals threatened with extinction, in the vulnerable category. As a preservation and conservation strategy, specimens kept in captivity by Brazilian Institutions are monitored by a management plan. In order to characterize and analyze the genetic variability of bush dog specimens, a cytogenetic analysis was carried out, and microsatellite data were also obtained through the use of 15 primers, originally developed for the domestic dog (Canis familiaris. All tested primers showed transferability and amplified fragment sizes similar to those described for the canine genome. From the total number of primers, eight were tested, and presented two polymorphic regions. Regarding cytogenetic analysis, one of the animals had chromosomal mosaicism, disqualifying it as a reproducer to form stocks. Thus, we concluded that the genetic evaluation of wild animals kept in captivity provides data that can help with the practice of exchange between different institutions, avoiding problems in the reproductive capacity of the breeding stock.The bush dog (Speothos venaticus is a South American canid, included in the IBAMA (Brazilian Institute of Environment and Renewable Natural Resources official list of animals threatened with extinction, in the vulnerable category. As a preservation and conservation strategy, specimens kept in captivity by Brazilian Institutions are monitored by a management plan. In order to characterize and analyze the genetic variability of bush dog specimens, a cytogenetic analysis was carried out, and microsatellite data were also obtained through the use of 15 primers, originally developed for the domestic dog (Canis familiaris. All tested primers showed transferability and amplified fragment sizes similar to those described for the canine genome. From the total number of

  12. A Debonded Sandwich Specimen Under Mixed Mode Bending (MMB)

    DEFF Research Database (Denmark)

    Quispitupa, Amilcar; Berggreen, Christian; Carlsson, Leif A.

    2008-01-01

    Face/core interface crack propagation in sandwich specimens is analyzed. A thorough analysis of the typical failure modes in sandwich composites was performed in order to design the MMB specimen to promote face/core debond fracture. Displacement, compliance and energy release rate expressions...... for the MMB specimen were derived from a superposition analysis. An experimental verification of the methodology proposed was performed using MMB sandwich specimens with H100 PVC foam core and E-glass/polyester non-crimp quadro-axial [0/45/90/-45]s DBLT-850 faces. Different mixed mode loadings were applied...

  13. [Effect of sandblasting particle sizes on bonding strength between porcelain and titanium fabricated by rapid laser forming].

    Science.gov (United States)

    Zhang, Li-jun; Wang, Zhong-yi; Gao, Bo; Gao, Yang; Zhang, Chun-bao

    2009-11-01

    To evaluate the effect of sandblasting particle sizes of Al2O3 on the bonding strength between porcelain and titanium fabricated by laser rapid forming (LRF). The thermal expansion coefficient, roughness (Ra), contact angle, surface morphology of titanium surface and the bonding strength between titanium and porcelain were evaluated after the titanium surface being sandblasted using different sizes of Al2O3 (50 microm, 120 microm, 250 microm) at a pressure of 0.5 MPa. The cast titanium specimens were used as control, and were sandblasted with 50 microm Al2O3 at the same pressure. The thermal expansion coefficient of cast titanium [(9.84 +/- 0.42) x 10(-6)/ degrees C] and LRF Ti [(9.79 +/- 0.31) x 10(-6)/ degrees C) matched that of Noritake Ti-22 dentin porcelain [(8.93 +/- 0.36) x 10(-6)/ degrees C). When larger size of Al2O3 was used, the value of Ra and contact angle increased as well. There was no significant difference in bonding strength between the LRF Ti-50 microm [(25.91 +/- 1.02) MPa] and cast titanium [(26.42 +/- 1.65) MPa]. Significantly lower bonding strength was found in LRF Ti-120 microm [(21.86 +/- 1.64) MPa] and LRF Ti-250 microm [(19.96 +/- 1.03) MPa]. The bond strength between LRF Ti and Noritake Ti-22 dentin porcelain was above the lower limit value in the ISO 9693 (25 MPa) after using 50 microm Al2O3 sandblasting in 0.5MPa air pressure.

  14. Response trajectories capture the continuous dynamics of the size congruity effect.

    Science.gov (United States)

    Faulkenberry, Thomas J; Cruise, Alexander; Lavro, Dmitri; Shaki, Samuel

    2016-01-01

    In a comparison task involving numbers, the size congruity effect refers to the general finding that responses are usually faster when there is a match between numerical size and physical size (e.g., 2-8) than when there is a mismatch (e.g., 2-8). In the present study, we used computer mouse tracking to test two competing models of the size congruity effect: an early interaction model, where interference occurs at an early representational stage, and a late interaction model, where interference occurs as dynamic competition between response options. In three experiments, we found that the curvature of responses for incongruent trials was greater than for congruent trials. In Experiment 2 we showed that this curvature effect was reliably modulated by the numerical distance between the two stimulus numbers, with large distance pairs exhibiting a larger curvature effect than small distance pairs. In Experiment 3 we demonstrated that the congruity effects persist into response execution. These findings indicate that incongruities between numerical and physical sizes are carried throughout the response process and result from competition between parallel and partially active response options, lending further support to a late interaction model of the size congruity effect. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. The influence of orientation and practical size on the interface fracture of a bone-nano composite cement

    International Nuclear Information System (INIS)

    Ilik, Igor; Khandaker, Morshed

    2010-01-01

    Clinical follow-up studies in cemented total hip arthroplasties found that femoral prosthesis loosening is caused by the fracture of the bone-cement interfaces. The research objectives were to determine whether orientation of the bone has any influence on the interface fracture strength, and to determine whether inclusion of micro/nano sizes MgO particles on Cobalt HV bone cement has any influence on the interface fracture strength. Flexural tests were conducted on five groups of specimens to find Young Modulus and bending strength: (1) longitudinal bone, (2) transverse bone, (3) pure cement particles, (4) cement with 36 im and 27 nm MgO particles, and (5) cement with 27nm MgO particles. Also, fracture tests were conducted on six groups of bone-cement specimen to find interface fracture toughness: (1) longitudinal bone-cement without MgO particles, (2) transverse bone-cement without MgO particles, (3) longitudinal bone-cement with 36 im MgO particles, (4) transverse bone-cement with 36 im MgO particles, (5) , longitudinal bone-cement with 27 nm MgO particles, and (6) transverse bone-cement with 27 nm MgO particles. Transverse bone specimen was 14% stiffer than longitudinal specimen, while bending strength and fracture toughness of longitudinal specimen was 29% and 2.6 times lower than the transverse specimen, respectively. Reduction of Young's modulus (7.3%), bending strength (27%) and fracture toughness (16%) was observed by the inclusion of microsize MgO particles, and a reduction of the Young's Modulus (19%), bending strength (21%),and fracture toughness (19%) for nanosize MgO particles. The interface toughness of the transverse bone infused with 27nm MgO was about 6 times higher than transverse bone infused with 36 im particles of MgO. Preliminary studies show that orientation of the bone has significant influence on the interface fracture. MgO particles size have a significant effect on the strength of the bone - cement interface.(Author)

  16. SHOULD EVERY APPENDECECTOMY SPECIMEN BE SUBJECTED TO HISTOPATHOLOGICAL EXAMINATION? A RETROSPECTIVE STUDY OF HISTOLOGICAL FINDINGS IN APPENDICECTOMY SPECIMENS

    Directory of Open Access Journals (Sweden)

    Shahanuma Shaik

    2017-12-01

    Full Text Available BACKGROUND Appendicitis is one of the commonest surgical emergencies with a lifetime risk of 7-8%. The appendicectomy specimens operated upon clinically-suspected appendicitis often appear normal on gross examination, but histopathological evaluation may reveal a diverse underlying pathology. Therefore, for accurate diagnosis, histopathological examination of all appendicectomy specimens is mandatory. MATERIALS AND METHODS A retrospective study of 175 appendicectomy cases operated over a period of two years. The clinical data and histopathological reports were reviewed and various histopathological findings are categorised. RESULTS Out of the total 175 appendicectomies, 155 emergency appendicectomy cases were included in the study, while 20 cases of incidental appendicectomy were excluded. The peak incidence was found in the 2nd and 3rd decades with male predominance. Among the 155 specimens, 96.8% had histological features of appendicitis and 1.9% were normal appendix. The unusual histopathological findings were Carcinoid tumour and Enterobius vermicularis. CONCLUSION The definitive diagnoses of appendicitis as well as the unusual incidental findings that were missed intraoperatively are established by histopathological examination. The study supports the histological examination of all resected appendicectomy specimens.

  17. Finite-size effects on multibody neutrino exchange

    CERN Document Server

    Abada, A; Rodríguez-Quintero, J; Abada, As

    1998-01-01

    The effect of multibody massless neutrino exchanges between neutrons inside a finite-size neutron star is studied. We use an effective Lagrangian, which incorporates the effect of the neutrons on the neutrinos. Following Schwinger, it is shown that the total interaction energy density is computed by comparing the zero point energy of the neutrino sea with and without the star. It has already been shown that in an infinite-size star the total energy due to neutrino exchange vanishes exactly. The opposite claim that massless neutrino exchange would produce a huge energy is due to an improper summation of an infrared-divergent quantity. The same vanishing of the total energy has been proved exactly in the case of a finite star in a one-dimensional toy model. Here we study the three-dimensional case. We first consider the effect of a sharp star border, assumed to be a plane. We find that there is a non- vanishing of the zero point energy density difference between the inside and the outside due to the refraction ...

  18. Constructing kinetics fatigue diagrams using testing results obtained on a machine with rigid loading for specimens of various thickness

    International Nuclear Information System (INIS)

    Simin'kovich, V.N.; Gladkij, Ya.N.; Deev, N.A.

    1981-01-01

    Bending tests of 40KhS steel specimens, tempered at 200 and 500 deg C, are conducted to investigate the possible effects of specimen thickness on fatigue crack growth. Kinetic fatigue diagrams are constructed using the investigation results. An increase in crack growth with thickness is observed only in high-tempered specimens. Changes in specimen thickness do not affect crack growth in 40KhS low-tempered steel [ru

  19. An Effect Size Measure for Raju's Differential Functioning for Items and Tests

    Science.gov (United States)

    Wright, Keith D.; Oshima, T. C.

    2015-01-01

    This study established an effect size measure for differential functioning for items and tests' noncompensatory differential item functioning (NCDIF). The Mantel-Haenszel parameter served as the benchmark for developing NCDIF's effect size measure for reporting moderate and large differential item functioning in test items. The effect size of…

  20. Synthesis of nanometer-size inorganic materials for the examination of particle size effects on heterogeneous catalysis

    Science.gov (United States)

    Emerson, Sean Christian

    The effect of acoustic and hydrodynamic cavitation on the precipitation of inorganic catalytic materials, specifically titania supported gold, was investigated. The overall objective was to understand the fundamental factors involved in synthesizing nanometer-size catalytic materials in the 1--10 nm range in a cavitating field. Materials with grain sizes in this range have been associated with enhanced catalytic activity compared to larger grain size materials. A new chemical approach was used to produce titania supported gold by co-precipitation with higher gold yields compared to other synthesis methods. Using this approach, it was determined that acoustic cavitation was unable to influence the gold mean crystallite size compared to non-sonicated catalysts. However, gold concentration on the catalysts was found to be very important for CO oxidation activity. By decreasing the gold concentration from a weight loading of 0.50% down to approximately 0.05%, the rate of reaction per mole of gold was found to increase by a factor of 19. Hydrodynamic cavitation at low pressures (6.9--48 bar) was determined to have no effect on gold crystallite size at a fixed gold content for the same precipitation technique used in the acoustic cavitation studies. By changing the chemistry of the precipitation system, however, it was found that a synergy existed between the dilution of the gold precursor solution, the orifice diameter, and the reducing agent addition rate. Individually, these factors were found to have little effect and only their interaction allowed gold grain size control in the range of 8--80 nm. Further modification of the system chemistry and the use of hydrodynamic cavitation at pressures in excess of 690 bar allowed the systematic control of gold crystallite size in the range of 2--9 nm for catalysts containing 2.27 +/- 0.17% gold. In addition, it was shown that the enhanced mixing due to cavitation led to larger gold yields compared to classical syntheses. The

  1. Cracking and Failure in Rock Specimen Containing Combined Flaw and Hole under Uniaxial Compression

    Directory of Open Access Journals (Sweden)

    Xiang Fan

    2018-01-01

    Full Text Available Flaw is a key factor influencing failure behavior of a fractured specimen. In the present study, rectangular-flawed specimens were prepared using sandstone to investigate the effect of flaw on failure behavior of rock. Open flaw and cylindrical hole were simultaneously precut within rock specimens using high-pressure water jet cutting technology. Five series of specimens including intact, single-hole-alone, two-hole-alone, single-hole and two-flaw, and two-hole and single-flaw blocks were prepared. Uniaxial compressive tests using a rigid servo control instrument were carried out to investigate the fracture processes of these flawed specimens. It is observed that during loading, internal stress always intensively distributed at both sidewalls of open hole, especially at midpoint of sidewalls, so rock crumb flaking was firstly observed among all sandstone specimens containing single hole or two holes. Cracking around open hole is associated with the flaw inclination angle which was observed in Series III and V. Crack easily initiated at the tips of flaw with inclination angles of 0°, 30°, and 60° but hard for 90° in Series III and V. Rock burst was the major failure mode among most tested specimens, which generally induced new cracks and finally created crater shape. Additionally, due to extrusion between blocks, new shear or tensile cracks were generated and the rock specimen surface spalled. Eventually, four typical failure processes including rock crumb flaking, crack initiation and propagation, rock burst, and second rupture, were summarized.

  2. Effects of microstructures and creep conditions on the fractal dimension of grain boundary fracture in high-temperature creep of heat-resistant alloys

    International Nuclear Information System (INIS)

    Tanaka, Manabu

    1993-01-01

    The effects of microstructural aspects, such as grain size and grain boundary configuration, and creep conditions on the fractal dimension of the grain boundary fracture were examined using several heat-resistant alloys, principally in an analysis scale range between one grain boundary length and specimen size. Grain boundary fracture surface profiles in the heat-resistant alloys exhibited a fractal nature in the scale range between one grain boundary length and specimen size as well as in the scale range below one grain boundary length. The fractal dimension of the grain boundary fracture slightly increased with decreasing grain size and was generally a little larger in the specimens with serrated grain boundaries than in those with straight grain boundaries. The fractal dimension of the grain boundary and the number of grain boundary microcracks which affected the grain boundary fracture patterns were a little larger in the specimen with the smaller grain size, and were also larger in the specimen with serrated grain boundaries. The fractal dimension of the grain boundary fracture increased with decreasing creep stress in the temperature range from 973 to 1422 K in these alloys, since more grain boundary microcracks existed in the specimens ruptured under the lower stresses at the higher temperatures. (orig.) [de

  3. Effects of anion size and concentration on electrolyte invasion into molecular-sized nanopores

    International Nuclear Information System (INIS)

    Liu Ling; Chen Xi; Kim, Taewan; Han Aijie; Qiao Yu

    2010-01-01

    When an electrolyte solution is pressurized into a molecular-sized nanopore, oppositely charged ions are strongly inclined to aggregate, which effectively reduces the ion solubility to zero. Inside the restrictive confinement, a unique quasi-periodic structure is formed where the paired ion couples are periodically separated by a number of water molecules. As the anion size or ion concentration varies, the geometrical characteristics of the confined ion structure would change considerably, leading to a significant variation in the transport pressure. Both experimental and simulation results indicate that, contradictory to the prediction of conventional theory, infiltration pressure decreases as the anions become larger.

  4. Study of Cluster-size Effect on Damage Formation

    International Nuclear Information System (INIS)

    Aoki, Takaaki; Seki, Toshio; Nakai, Atsuko; Matsuo, Jiro; Takaoka, Gikan

    2003-01-01

    Computer simulation and experiments were performed in order to understand the effect of cluster size on damage formation. Results of molecular dynamics simulations of cluster impact on solid targets derived the model function, which explains the relationship among cluster size, incident energy and number of displacements. On the other hand, time of flight mass measurement system was installed a cluster irradiation system, so that cluster ion beam which cluster size distribution is well known can be irradiated on the target. The damage properties under various cluster irradiation conditions were examined using RBS. The results from computer simulations and experiments showed good agreements with each other, which suggests that irradiation damage by cluster ion beam can be controlled by selecting cluster size distribution and incident energy

  5. Grain-to-Grain Variations in NbC Particle Size Distributions in an Austenitic Stainless Steel

    DEFF Research Database (Denmark)

    Barlow, Claire; Ralph, B.; Silverman, B.

    1979-01-01

    Quantitative information has been obtained concerning the size distributions of NbC precipitate particles in different grains in a deformed and aged austenitic stainless steel specimen. The precipitate size distributions obtained differ from one grain to another. The average disparity measured be...

  6. Investigation of UT procedure for crack depth sizing by phased array UT in Ni-based alloy weld

    International Nuclear Information System (INIS)

    Hirasawa, Taiji; Fukutomi, Hiroyuki

    2013-01-01

    Recently, it has been reported that the primary water stress corrosion cracking (PWSCC) has occurred in nickel based alloy weld components such as steam generator safe end weld, reactor vessel safe end weld, and so on, in PWR. Defect detection and sizing are important in order to ensure the reliable operation and life extension of nuclear power plants. In the reactor vessel safe end weld, it was impossible to measure crack depth of PWSCC. The cracks have occurred in the axial direction of the safe end weld. Furthermore, the cracks had some features such as deep, large aspect ratio (ratio of crack depth and length), sharp geometry of crack tip, and so on. Therefore, development and improvement of defect depth sizing capabilities by ultrasonic testing (UT) have been required. Phased array UT technique was applied with regard to defect depth sizing at the inside inspection in Ni-based alloy welds. Phased array UT was examined a standard block specimen with side drilled holes (SDHs). From the experimental results, the performance of linear array probes and dual matrix array probe were investigated. In the basis of the results, UT procedure for defect depth sizing was investigated and proposed. The UT procedure was applied to the defect depth measurement in Ni-based alloy weld specimen with electric discharge machine (EDM) notches. From these results, good accuracy of defect depth sizing by phased array UT for the inside inspection was shown. Therefore, it was clarified the effectiveness of the UT procedure for defect depth sizing in Ni-based alloy weld. (author)

  7. EFFECTS OF ULTRASOUND ON THE MORPHOLOGY, PARTICLE SIZE, CRYSTALLINITY, AND CRYSTALLITE SIZE OF CELLULOSE

    Directory of Open Access Journals (Sweden)

    SUMARI SUMARI

    2014-05-01

    Full Text Available The aim of this study is to optimize ultrasound treatment to produce fragment of cellulose that is low in particles size, crystallite size, and crystallinity. Slurry of 1 % (w/v the cellulose was sonicated at different time periods and temperatures. An ultrasonic reactor was operated at 300 Watts and 28 kHz to cut down the polymer into smaller particles. We proved that ultrasound damages and fragments the cellulose particles into shorter fibers. The fiber lengths were reduced from in the range of 80-120 µm to 30-50 µm due to an hour ultrasonication and became 20-30 µm after 5 hours. It was also found some signs of erosion on the surface and stringy. The acoustic cavitation also generated a decrease in particle size, crystallinity, and crystallite size of the cellulose along with increasing sonication time but it did not change d-spacing. However, the highest reduction of particle size, crystallite size, and crystallinity of the cellulose occurred within the first hour of ultrasonication, after which the efficiency was decreased. The particle diameter, crystallite size, and crystallinity were decreased from 19.88 µm to 15.96 µm, 5.81 Å to 2.98 Å, and 77.7% to 73.9% respectively due to an hour ultrasound treatment at 40 °C. The treatment that was conducted at 40 °C or 60 °C did not give a different effect significantly. Cellulose with a smaller particle and crystallite size as well as a more amorphous shape is preferred for further study.

  8. Evaluation of the Behavior of Technova Corporation Rod-Stiffened Stitched Compression Specimens

    Science.gov (United States)

    Jegley, Dawn C.

    2013-01-01

    Under Space Act Agreement 1347 between NASA and Technova Corporation, Technova designed and fabricated two carbon-epoxy crippling specimens and NASA loaded them to failure in axial compression. Each specimen contained a pultruded rod stiffener which was held to the specimen skin with through-the-thickness stitches. One of these specimens was designed to be nominally the same as pultruded rod stitched specimens fabricated by Boeing under previous programs. In the other specimen, the rod was prestressed in a Technova manufacturing process to increase its ability to carrying compressive loading. Experimental results demonstrated that the specimen without prestressing carried approximately the same load as the similar Boeing specimens and that the specimen with prestressing carried significantly more load than the specimen without prestressing.

  9. Vacuum sealing and cooling as methods to preserve surgical specimens

    DEFF Research Database (Denmark)

    Kielsgaard Kristensen, Thomas; Engvad, Birte; Nielsen, Ole

    2011-01-01

    Recently, vacuum-based preservation of surgical specimens has been proposed as a safe alternative to formalin fixation at the surgical theater. The method seems feasible from a practical point of view, but no systematic study has examined the effect of vacuum sealing alone with respect to tissue...

  10. Development of realistic concrete models including scaling effects

    International Nuclear Information System (INIS)

    Carpinteri, A.

    1989-09-01

    Progressive cracking in structural elements of concrete is considered. Two simple models are applied, which, even though different, lead to similar predictions for the fracture behaviour. Both Virtual Crack Propagation Model and Cohesive Limit Analysis (Section 2), show a trend towards brittle behaviour and catastrophical events for large structural sizes. A numerical Cohesive Crack Model is proposed (Section 3) to describe strain softening and strain localization in concrete. Such a model is able to predict the size effects of fracture mechanics accurately. Whereas for Mode I, only untieing of the finite element nodes is applied to simulate crack growth, for Mixed Mode a topological variation is required at each step (Section 4). In the case of the four point shear specimen, the load vs. deflection diagrams reveal snap-back instability for large sizes. By increasing the specimen sizes, such instability tends to reproduce the classical LEFM instability. Remarkable size effects are theoretically predicted and experimentally confirmed also for reinforced concrete (Section 5). The brittleness of the flexural members increases by increasing size and/or decreasing steel content. On the basis of these results, the empirical code rules regarding the minimum amount of reinforcement could be considerably revised

  11. Photoinduced non-linear optical effects in the ZnS-Al, In-Sn doped film-glass nanometer-sized interfaces

    International Nuclear Information System (INIS)

    Kityk, I.V.; Makowska-Janusik, M.; Ebothe, J.; El Hichou, A.; El Idrissi, B.; Addou, M.

    2002-01-01

    The effective na