Small punch tensile/fracture test data and 3D specimen surface data on Grade 91 ferritic/martensitic steel from cryogenic to room temperature.

Science.gov (United States)

Bruchhausen, Matthias; Lapetite, Jean-Marc; Ripplinger, Stefan; Austin, Tim

2016-12-01

Raw data from small punch tensile/fracture tests at two displacement rates in the temperature range from -196 °C to room temperature on Grade 91 ferritic/martensitic steel are presented. A number of specimens were analyzed after testing by means of X-ray computed tomography (CT). Based on the CT volume data detailed 3D surface maps of the specimens were established. All data are open access and available from Online Data Information Network (ODIN)https://odin.jrc.ec.europa.eu. The data presented in the current work has been analyzed in the research article "On the determination of the ductile to brittle transition temperature from small punch tests on Grade 91 ferritic-martensitic steel" (M. Bruchhausen, S. Holmström, J.-M. Lapetite, S. Ripplinger, 2015) [1].

Urine specimen validity test for drug abuse testing in workplace and court settings.

Science.gov (United States)

Lin, Shin-Yu; Lee, Hei-Hwa; Lee, Jong-Feng; Chen, Bai-Hsiun

2018-01-01

In recent decades, urine drug testing in the workplace has become common in many countries in the world. There have been several studies concerning the use of the urine specimen validity test (SVT) for drug abuse testing administered in the workplace. However, very little data exists concerning the urine SVT on drug abuse tests from court specimens, including dilute, substituted, adulterated, and invalid tests. We investigated 21,696 submitted urine drug test samples for SVT from workplace and court settings in southern Taiwan over 5 years. All immunoassay screen-positive urine specimen drug tests were confirmed by gas chromatography/mass spectrometry. We found that the mean 5-year prevalence of tampering (dilute, substituted, or invalid tests) in urine specimens from the workplace and court settings were 1.09% and 3.81%, respectively. The mean 5-year percentage of dilute, substituted, and invalid urine specimens from the workplace were 89.2%, 6.8%, and 4.1%, respectively. The mean 5-year percentage of dilute, substituted, and invalid urine specimens from the court were 94.8%, 1.4%, and 3.8%, respectively. No adulterated cases were found among the workplace or court samples. The most common drug identified from the workplace specimens was amphetamine, followed by opiates. The most common drug identified from the court specimens was ketamine, followed by amphetamine. We suggest that all urine specimens taken for drug testing from both the workplace and court settings need to be tested for validity. Copyright © 2017. Published by Elsevier B.V.

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

Investigation of the influence of different surface regularization methods for cylindrical concrete specimens in axial compression tests

Directory of Open Access Journals (Sweden)

R. MEDEIROS

Full Text Available ABSTRACT This study was conducted with the aim of evaluating the influence of different methods for end surface preparation of compressive strength test specimens. Four different methods were compared: a mechanical wear method through grinding using a diamond wheel established by NBR 5738; a mechanical wear method using a diamond saw which is established by NM 77; an unbonded system using neoprene pads in metal retainer rings established by C1231 and a bonded capping method with sulfur mortar established by NBR 5738 and by NM 77. To develop this research, 4 concrete mixes were determined with different strength levels, 2 of group 1 and 2 of group 2 strength levels established by NBR 8953. Group 1 consists of classes C20 to C50, 5 in 5MPa, also known as normal strength concrete. Group 2 is comprised of class C55, C60 to C100, 10 in 10 MPa, also known as high strength concrete. Compression tests were carried out at 7 and 28 days for the 4 surface preparation methods. The results of this study indicate that the method established by NBR 5738 is the most effective among the 4 strengths considered, once it presents lower dispersion of values obtained from the tests, measured by the coefficient of variation and, in almost all cases, it demonstrates the highest mean of rupture test. The method described by NBR 5738 achieved the expected strength level in all tests.

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

Analysis of the applicability of fracture mechanics on the basis of large scale specimen testing

International Nuclear Information System (INIS)

Brumovsky, M.; Polachova, H.; Sulc, J.; Anikovskij, V.; Dragunov, Y.; Rivkin, E.; Filatov, V.

1988-01-01

The verification is dealt with of fracture mechanics calculations for WWER reactor pressure vessels by large scale model testing performed on the large testing machine ZZ 8000 (maximum load of 80 MN) in the Skoda Concern. The results of testing a large set of large scale test specimens with surface crack-type defects are presented. The nominal thickness of the specimens was 150 mm with defect depths between 15 and 100 mm, the testing temperature varying between -30 and +80 degC (i.e., in the temperature interval of T ko ±50 degC). Specimens with a scale of 1:8 and 1:12 were also tested, as well as standard (CT and TPB) specimens. Comparisons of results of testing and calculations suggest some conservatism of calculations (especially for small defects) based on Linear Elastic Fracture Mechanics, according to the Nuclear Reactor Pressure Vessel Codes which use the fracture mechanics values from J IC testing. On the basis of large scale tests the ''Defect Analysis Diagram'' was constructed and recommended for brittle fracture assessment of reactor pressure vessels. (author). 7 figs., 2 tabs., 3 refs

Stress-deformed state of cylindrical specimens during indirect tensile strength testing

Directory of Open Access Journals (Sweden)

Levan Japaridze

2015-10-01

Full Text Available In this study, the interaction between cylindrical specimen made of homogeneous, isotropic, and linearly elastic material and loading jaws of any curvature is considered in the Brazilian test. It is assumed that the specimen is diametrically compressed by elliptic normal contact stresses. The frictional contact stresses between the specimen and platens are neglected. The analytical solution starts from the contact problem of the loading jaws of any curvature and cylindrical specimen. The contact width, corresponding loading angle (2θ0, and elliptical stresses obtained through solution of the contact problems are used as boundary conditions for a cylindrical specimen. The problem of the theory of elasticity for a cylinder is solved using Muskhelishvili's method. In this method, the displacements and stresses are represented in terms of two analytical functions of a complex variable. In the main approaches, the nonlinear interaction between the loading bearing blocks and the specimen as well as the curvature of their surfaces and the elastic parameters of their materials are taken into account. Numerical examples are solved using MATLAB to demonstrate the influence of deformability, curvature of the specimen and platens on the distribution of the normal contact stresses as well as on the tensile and compressive stresses acting across the loaded diameter. Derived equations also allow calculating the modulus of elasticity, total deformation modulus and creep parameters of the specimen material based on the experimental data of radial contraction of the specimen.

Feasibility study of flexible phased array ultrasonic technology using irregular surface specimen

International Nuclear Information System (INIS)

Lee, Seung Pyo; Moon, Yong Sik; Jung, Nam Du

2015-01-01

Nuclear power plant contain many dissimilar metal welds that connect carbon steel components with stainless steel pipes using alloy 600 welding materials. Primary water stress corrosion cracks at dissimilar metal welds have been continuously reported around the world. In periodic integrity evaluations, dissimilar metal welds are examined using a generic ultrasonic testing procedure, KPD-UT-10. In this procedure, the gap between the probe and examination surface is limited to 1/32 inch (0.8 mm). It is not easy to test some dissimilar metal welds in Korean plants applying ordinary technology because of their tapered shapes and irregular surface conditions. This paper introduces a method for applying a flexible phased array technology to improve the reliability of ultrasonic testing results for various shapes and surface conditions. The artificial flaws in specimens with irregular surfaces were completely detected using the flexible phased array ultrasonic technology. Therefore, it can be said that the technology is applicable to field examination.

Feasibility study of flexible phased array ultrasonic technology using irregular surface specimen

Energy Technology Data Exchange (ETDEWEB)

Lee, Seung Pyo; Moon, Yong Sik; Jung, Nam Du [NDE Performance Demonstration Team, Korea Hydro and Nuclear Power, Central Research Institute, Daejeon (Korea, Republic of)

2015-02-15

Nuclear power plant contain many dissimilar metal welds that connect carbon steel components with stainless steel pipes using alloy 600 welding materials. Primary water stress corrosion cracks at dissimilar metal welds have been continuously reported around the world. In periodic integrity evaluations, dissimilar metal welds are examined using a generic ultrasonic testing procedure, KPD-UT-10. In this procedure, the gap between the probe and examination surface is limited to 1/32 inch (0.8 mm). It is not easy to test some dissimilar metal welds in Korean plants applying ordinary technology because of their tapered shapes and irregular surface conditions. This paper introduces a method for applying a flexible phased array technology to improve the reliability of ultrasonic testing results for various shapes and surface conditions. The artificial flaws in specimens with irregular surfaces were completely detected using the flexible phased array ultrasonic technology. Therefore, it can be said that the technology is applicable to field examination.

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.

Improved PID control for triaxial testing liquefied specimen

DEFF Research Database (Denmark)

Sabaliauskas, Tomas; Ibsen, Lars Bo

Using a frictionless triaxial apparatus, sand specimens can be tested at relatively high axial strains, even while liquefying. However, liquefying specimens have extremely nonlinear stiffness, thus standard PID control does not perform well. To maintain control over applied loads, the PID...... controller was modified to adapt to disturbed soil states. The proposed methods expand the scope of testing towards options which are otherwise inaccessible by triaxial testing....

46 CFR 57.06-4 - Production testing specimen requirements.

Science.gov (United States)

2010-10-01

... WELDING AND BRAZING Production Tests § 57.06-4 Production testing specimen requirements. (a) For test... 46 Shipping 2 2010-10-01 2010-10-01 false Production testing specimen requirements. 57.06-4... to welding shall not throw the finished test plate out of line by an angle of over 5°. (c) Where the...

Post-deformation examination of specimens subjected to SCC testing

Energy Technology Data Exchange (ETDEWEB)

Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Busby, Jeremy T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Leonard, Keith J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-09-01

This report details the results of post-radiation and post-deformation characterizations performed during FY 2015–FY 2016 on a subset of specimens that had previously been irradiated at high displacement per atom (dpa) damage doses. The specimens, made of commercial austenitic stainless steels and alloys, were subjected to stress-corrosion cracking tests (constant extension rate testing and crack growth testing) at the University of Michigan under conditions typical of nuclear power plants. After testing, the specimens were returned to Oak Ridge National Laboratory (ORNL) for further analysis and evaluation.

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)

A proposed standard round compact specimen for plane strain fracture toughness testing

Science.gov (United States)

Underwood, J. H.; Newman, J. C., Jr.; Seeley, R. R.

1980-01-01

A round, disk-shaped specimen is proposed as a standard test specimen for addition to ASTM Test for Plane-Strain Fracture Toughness of Metallic Materials (E 399-78A). The specimen is diametrically cracked, and loaded in the same way as the existing standard compact specimen. Tests and analyses were performed to verify that the proposed round compact specimen and associated stress intensity factor K solution are appropriate for a standard plane strain fracture toughness test. The use of the round compact specimen for other fracture tests is described.

LOCA scenario tests of irradiated fuel rod specimens

International Nuclear Information System (INIS)

Scott, Harold

2004-01-01

out that away from the burst region, for unirradiated cladding, the equivalent cladding reacted (ECR) and oxygen concentration decrease as expected with increasing wall thickness and decreasing inner-surface oxidation, but the hydrogen concentration increases dramatically to >3000 wppm near and just beyond the two neck regions. Characterization of the 2nd BWR test specimen has determined the degree of inner surface oxidation in the ballooned region and found the amount of secondary hydriding at and beyond the neck regions is less than 300 wppm. (Author)

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

The purpose of the U.S. Department of Energy Office of Nuclear Energy’s Light Water Reactor Sustainability (LWRS) Program is to develop technologies and other solutions that can improve the reliability, sustain the safety, and extend the operating lifetimes of nuclear power plants (NPPs) beyond 60 years. Since many important safety structures in an NPP are constructed of concrete, inspection techniques must be developed and tested to evaluate the internal condition. In-service containment structures generally do not allow for the destructive measures necessary to validate the accuracy of these inspection techniques. This creates a need for comparative testing of the various nondestructive evaluation (NDE) measurement techniques on concrete specimens with known material properties, voids, internal microstructure flaws, and reinforcement locations. A preliminary report detailed some of the challenges associated with thick reinforced concrete sections and prioritized conceptual designs of specimens that could be fabricated to represent NPP concrete structures for using in NDE evaluation comparisons. This led to the construction of the concrete specimen presented in this report, which has sufficient reinforcement density and cross-sectional size to represent an NPP containment wall. Details on how a suitably thick concrete specimen was constructed are presented, including the construction materials, final nominal design schematic, as well as formwork and rigging required to safely meet the desired dimensions of the concrete structure. The report also details the type and methods of forming the concrete specimen as well as information on how the rebar and simulated defects were embedded. Details on how the resulting specimen was transported, safely anchored, and marked to allow access for systematic comparative NDE testing of defects in a representative NPP containment wall concrete specimen are also given. Data collection using the MIRA Ultrasonic NDE equipment and

Effect of holes on the room temperature tensile behaviors of thin wall specimens with (210) side surface of Ni-base single crystal superalloy

Energy Technology Data Exchange (ETDEWEB)

Zhou, Z.J.; Liu, T.; Pu, S. [Superalloys Division, Institute of Metal Research, Chinese Academy of Sciences, No. 72, Wenhua Road, Shenyang 110016 (China); Xu, H. [Materials Fatigue and Fracture Division, Institute of Metal Research, Chinese Academy of Sciences, No. 72, Wenhua Road, Shenyang 110016 (China); Wang, L., E-mail: wangli@imr.ac.cn [Superalloys Division, Institute of Metal Research, Chinese Academy of Sciences, No. 72, Wenhua Road, Shenyang 110016 (China); Lou, L.H. [Superalloys Division, Institute of Metal Research, Chinese Academy of Sciences, No. 72, Wenhua Road, Shenyang 110016 (China)

2015-10-25

Tensile properties of Ni-base single crystal superalloy plate specimens with and without a hole at room temperature were studied in the present paper. During the testing process, an ARAMIS system based on the digital image correlation technique and in-situ scanning electron microscopy were employed to in-situ observe the strain distribution and slip traces development on the sample surfaces. It was demonstrated that the yield stress was decreased with the appearance of a hole due to the stress concentration. The results were analyzed based on the stress and strain states of specimens and the slip traces development observed on specimen surfaces. - Graphical abstract: The strain distribution for samples without and with a hole, respectively. - Highlights: • Tensile tests of plate specimens without and with a hole were performed. • Surface strain fields were in-situ observed by ARAMIS system. • Slip traces development on sample surfaces was in-situ observed by SEM. • The hole deteriorated both the tensile strength and elongation of the samples. • Tensile strength of specimens without and with a hole was discussed respectively.

Hydrogen embrittlement of titanium tested with fracture mechanics specimens

International Nuclear Information System (INIS)

Aho-Mantila, I.; Rahko, P.

1990-11-01

Titanium is one of the possible canister materials for spent nuclear fuel. The aim of this study is to determine whether the hydrogen embrittlement of titanium could be a possible deterioration mechanism of titanium canisters. This experimental study was preceded by a literature review and an experimental study on crack nucleation. Tests in this study were carried out with hydrogen charged fracture mechanics specimens. The studied hydrogen contents were as received, 100 ppm, 200 ppm, 500 ppm and 700 ppm and the types of the studied titanium were ASTM Grades 2 and 12. Test methods were slow tensile test (0.027 mm/h) and fatigue test (stress ratio 0.7 or 0.8 and frequency 5 Hz). According to the literature titanium may be embrittled by hydrogen at slow strain rates and cracking may occur under sustained load. In this study no evidence of hydrogen embrittlement was noticed in slow strain rate tension with bulk hydrogen contents up to 700 ppm. The fatigue tests of titanium Grades 2 and 12 containing 700 ppm hydrogen showed even slower crack growth compared to the as received condition. Very high hydrogen contents well in eccess of 700 ppm on the surface of titanium can, however, facilitate surface crack nucleation and crack growth, as shown in the previous study

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.)

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.

Development of piezoelectric ceramics driven fatigue testing machine for small specimens

International Nuclear Information System (INIS)

Saito, S.; Kikuchi, K.; Onishi, Y.; Nishino, T.

2002-01-01

A new fatigue testing machine with piezoelectric ceramics actuators was developed and a prototype was manufactured for high-cycle fatigue tests with small specimens. The machine has a simple mechanism and is compact. These features make it easy to set up and to maintain the machine in a hot cell. The excitation of the actuator can be transmitted to the specimen using a lever-type testing jig. More than 100 μm of displacement could be prescribed precisely to the specimen at a frequency of 50 Hz. This was sufficient performance for high-cycle bend fatigue tests on specimens irradiated at the SINQ target in Paul Scherrer Institute. The relationship of a displacement applied to the specimen and the strain of the necking part were obtained by experimental methods and by finite element method (FEM) calculations. Both results showed good agreement. This fact makes it possible to evaluate the strain of irradiated specimens by FEM simulations

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

Fabrication and testing of prestressed composite rotor blade spar specimens

Science.gov (United States)

Gleich, D.

1974-01-01

Prestressed composite spar specimens were fabricated and evaluated by crack propagation and ballistic penetration tests. The crack propagation tests on flawed specimens showed that the prestressed composite spar construction significantly suppresses crack growth. Damage from three high velocity 30 caliber projectile hits was confined to three small holes in the ballistic test specimen. No fragmentation or crack propagation was observed indicating good ballistic damage resistance. Rotor attachment approaches and improved structural performance configurations were identified. Design theory was verified by tests. The prestressed composite spar configuration consisted of a compressively prestressed high strength ARDEFORM 301 stainless steel liner overwrapped with pretensioned S-994 fiberglass.

Quantitative sensing of corroded steel rebar embedded in cement mortar specimens using ultrasonic testing

Science.gov (United States)

Owusu Twumasi, Jones; Le, Viet; Tang, Qixiang; Yu, Tzuyang

2016-04-01

Corrosion of steel reinforcing bars (rebars) is the primary cause for the deterioration of reinforced concrete structures. Traditional corrosion monitoring methods such as half-cell potential and linear polarization resistance can only detect the presence of corrosion but cannot quantify it. This study presents an experimental investigation of quantifying degree of corrosion of steel rebar inside cement mortar specimens using ultrasonic testing (UT). A UT device with two 54 kHz transducers was used to measure ultrasonic pulse velocity (UPV) of cement mortar, uncorroded and corroded reinforced cement mortar specimens, utilizing the direct transmission method. The results obtained from the study show that UPV decreases linearly with increase in degree of corrosion and corrosion-induced cracks (surface cracks). With respect to quantifying the degree of corrosion, a model was developed by simultaneously fitting UPV and surface crack width measurements to a two-parameter linear model. The proposed model can be used for predicting the degree of corrosion of steel rebar embedded in cement mortar under similar conditions used in this study up to 3.03%. Furthermore, the modeling approach can be applied to corroded reinforced concrete specimens with additional modification. The findings from this study show that UT has the potential of quantifying the degree of corrosion inside reinforced cement mortar specimens.

Uniaxial compression tests on diesel contaminated frozen silty soil specimens

International Nuclear Information System (INIS)

Chenaf, D.; Stampli, N.; Bathurst, R.; Chapuis, R.P.

1999-01-01

Results of a uniaxial, unconfined compression test on artificial diesel-contaminated and uncontaminated frozen silty soils are discussed. The testing program involved 59 specimens. The results show that for the same fluid content, diesel contamination reduced the strength of the frozen specimens by increasing the unfrozen water content. For example, in specimens containing 50 per cent diesel oil of the fluid content by weight the maximum strength was reduced by 95 per cent compared to the strength of an uncontaminated specimen. Diesel contamination was also shown to contribute to the slippage between soil particles by acting as a lubricant, thus accelerating the loss of compressive strength.13 refs., 18 figs

Catalogue of test specimens for non-destructive examination

International Nuclear Information System (INIS)

1985-05-01

One of the key elements in assuring the integrity of reactor primary circuits is the availability of trustworthy non-destructive methods for detecting dangerous defects that may be present. Various approaches to making such examinations are being developed, including the use of ultrasonic and radiographic techniques. To demonstrate their capability and reliability, they must be tested on steel specimens reproducing the various types of faults which may arise in real primary circuit vessels and piping. Such specimens are costly to fabricate. It is therefore clearly desirable that existing specimens should be made accessible to as many organisations as possible for testing. This catalogue contains detailed Information on forty-odd deliberately flawed plates, blocks, vessels, etc. which have been produced in OECD countries, along with the name of a contact person to whom inquiries should be directed in each case

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)

The influence of microstructure on surface strain distributions in a nickel micro-tension specimen

International Nuclear Information System (INIS)

Turner, T J; Shade, P A; Schuren, J C; Groeber, M A

2013-01-01

This work presents an integrated experimental and modeling approach for examining the deformation of a pure nickel polycrystal utilizing micro-mechanical testing and a crystal-based elasto-viscoplastic finite-element model (CPFEM). The objective is to study the influence of microstructure on the heterogeneous deformation in polycrystalline materials, and to utilize a modeling framework to explore aspects of the deformation that are difficult or impossible to measure experimentally. To accomplish this, a micro-tension specimen containing 259 grains was created from a pure nickel foil material and deformed in uniaxial tension. After the deformation, the specimen was destructively serial sectioned in concert with electron back scattering diffraction, and these data were used to instantiate a CPFEM simulation. The material parameters in the CPFEM model were calibrated by matching the experimental macroscopic stress-strain response of the micro-tension specimen, and then the simulation results were compared with experimental surface deformations measured with digital image correlation. After validating the simulation results by comparing measured and predicted surface strain distributions, a parametric study of the influence of both crystallographic texture and grain morphology is presented to better understand the influence of microstructure on the development of heterogeneous deformation in the pure nickel polycrystalline material. (paper)

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

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.

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

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

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

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.

A test specimen for characterizing the fracture energy of interfaces in composites

International Nuclear Information System (INIS)

Shaw, L.; Abbaschian, R.

1993-01-01

A sandwich-type chevron-notched specimen, which has a phase angle of loading near zero, is proposed to measure interfacial fracture energy arising mainly from chemical bonding. With the specimen configuration of this kind, the advantages from both sandwich test specimens and chevron-notched specimens can be combined to provide an easy and accurate test for the measurement of interfacial fracture energy. The validity of the specimen has been analyzed in terms of the mechanics of sandwich-type specimens and chevron-notched specimens, and demonstrated using the Al 2 O 3 /Nb bimaterial system. The results show that for a phase angle of loading around -7 degrees the Al 2 O 3 /Nb interface has a fracture energy of 9.3 ± 0.2 J/m 2 . 39 refs

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)

Instrumented Impact Testing: Influence of Machine Variables and Specimen Position

International Nuclear Information System (INIS)

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

2008-01-01

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

Instrumented Impact Testing: Influence of Machine Variables and Specimen Position

Energy Technology Data Exchange (ETDEWEB)

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

2008-09-15

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

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

Optimization of tensile method and specimen geometry in modified ring tensile test

International Nuclear Information System (INIS)

Kitano, Koji; Fuketa, Toyoshi; Sasajima, Hideo; Uetsuka, Hiroshi

2001-03-01

Several techniques in ring tensile test are proposed in order to evaluate mechanical properties of cladding under hoop loading condition caused by pellet/cladding mechanical interaction (PCMI). In the modified techniques, variety of tensile methods and specimen geometry are being proposed in order to limit deformation within the gauge section. However, the tensile method and the specimen geometry were not determined in the modified techniques. In the present study, we have investigated the tensile method and the specimen geometry through finite element method (FEM) analysis of specimen deformation and tensile test on specimens with various gauge section geometries. In using two-piece tensile tooling, the mechanical properties under hoop loading condition can be correctly evaluated when deformation part (gauge section) is put on the top of a half-mandrel, and friction between the specimen and the half-mandrel is reduced with Teflon tape. In addition, we have shown the optimum specimen geometry for PWR 17 by 17 type cladding. (author)

46 CFR 54.05-5 - Toughness test specimens.

Science.gov (United States)

2010-10-01

... shown in Figure 4 of the specification. Special attention is drawn to the fact that the Charpy Keyhole....090-inch. In preparing weld specimens for dropweight testing, weld reinforcement shall be ground flush...

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

Test of large-scale specimens and models as applied to NPP equipment materials

International Nuclear Information System (INIS)

Timofeev, B.T.; Karzov, G.P.

1993-01-01

The paper presents the test results on low-cycle fatigue, crack growth rate and fracture toughness of large-scale specimens and structures, manufactured from steel, widely applied in power engineering industry and used for the production of NPP equipment with VVER-440 and VVER-1000 reactors. The obtained results are compared with available test results of standard specimens and calculation relations, accepted in open-quotes Calculation Norms on Strength.close quotes At the fatigue crack initiation stage the experiments were performed on large-scale specimens of various geometry and configuration, which permitted to define 15X2MFA steel fracture initiation resistance by elastic-plastic deformation of large material volume by homogeneous and inhomogeneous state. Besides the above mentioned specimen tests in the regime of low-cycle loading, the test of models with nozzles were performed and a good correlation of the results on fatigue crack initiation criterium was obtained both with calculated data and standard low-cycle fatigue tests. It was noted that on the Paris part of the fatigue fracture diagram a specimen thickness increase does not influence fatigue crack growth resistance by tests in air both at 20 and 350 degrees C. The estimation of the comparability of the results, obtained on specimens and models was also carried out for this stage of fracture. At the stage of unstable crack growth by static loading the experiments were conducted on specimens of various thickness for 15X2MFA and 15X2NMFA steels and their welded joints, produced by submerged arc welding, in as-produced state (the beginning of service) and after embrittling heat treatment, simulating neutron fluence attack (the end of service). The obtained results give evidence of the possibility of the reliable prediction of structure elements brittle fracture using fracture toughness test results on relatively small standard specimens. 35 refs., 23 figs

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)

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.

Effects of cavity surface temperature on mechanical properties of specimens with and without a weld line in rapid heat cycle molding

International Nuclear Information System (INIS)

Wang, Guilong; Zhao, Guoqun; Wang, Xiaoxin

2013-01-01

Highlights: ► Higher cavity surface temperature reduces tensile strength of non-weldline part. ► Higher cavity surface temperature increases weldline tensile strength for PS and PP. ► Higher cavity surface temperature reduces weldline tensile strength for ABS, ABS/PMMA, ABS/PMMA/nano-C a CO 3 and FRPP. ► Tensile strength is reduced more by the weldline than impact strength. ► FRPP has the lowest weld line factor than other plastics without reinforced fibers. - Abstract: Rapid heat cycle molding (RHCM) is a recently developed injection molding technology to enhance surface esthetic of the parts. By rapid heating and cooling of mold cavity surfaces in molding process, it can greatly alleviate or even eliminate the surface defects such as flow mark, weld line, glass fiber rich surface, silver mark, jetting mark, and swirl mark, and also improve gloss finish and dimensional accuracy without prolonging the molding cycle. Besides surface esthetic, mechanical property is also a very import issue for the molded plastic part. The aim of this study is focusing on the effects of the cavity surface temperature just before filling, T cs , in RHCM on the mechanical strength of the specimen with and without weld line. Six kinds of typical plastics including polystyrene (PS), polypropylene (PP), acrylonitrile butadiene styrene (ABS), acrylonitrile butadiene styrene/polymethylmethacrylate (ABS/PMMA), ABS/PMMA/nano-C a CO 3 and glass fiber reinforced polypropylene (FRPP) are used in experiments. The specimens with and without a weld line are produced with the different T cs on the developed electric-heating RHCM system. Tensile tests and notched Izod impact tests are conducted to characterize the mechanical strength of the specimens molded with different cavity surface temperatures. Simulations, differential scanning calorimetry (DSC), scanning electron microscope (SEM) and optical microscope are implemented to explain the impact mechanism of T cs on mechanical properties

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)

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

International Nuclear Information System (INIS)

Manahan, M.P.; Williams, J.; Martukanitz, R.P.

1993-01-01

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

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)

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...

Standard practice for preparation and use of direct tension stress-corrosion test specimens

CERN Document Server

American Society for Testing and Materials. Philadelphia

1985-01-01

1.1 This practice covers procedures for designing, preparing, and using ASTM standard tension test specimens for investigating susceptibility to stress-corrosion cracking. Axially loaded specimens may be stressed quantitatively with equipment for application of either a constant load, constant strain, or with a continuously increasing strain. 1.2 Tension test specimens are adaptable for testing a wide variety of product forms as well as parts joined by welding, riveting, or various other methods. 1.3 The exposure of specimens in a corrosive environment is treated only briefly because other standards are being prepared to deal with this aspect. Meanwhile, the investigator is referred to Practices G35, G36, G37, and G44, and to ASTM Special Technical Publication 425 (1).

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.

A curved beam test specimen for determining the interlaminar tensile strength of a laminated composite

Science.gov (United States)

Hiel, Clement C.; Sumich, Mark; Chappell, David P.

1991-01-01

A curved beam type of test specimen is evaluated for use in determining the through-the-thickness strength of laminated composites. Two variations of a curved beam specimen configuration (semicircular and elliptical) were tested to failure using static and fatigue loads. The static failure load for the semicircular specimens was found to be highly sensitive to flaw content, with the specimens falling into two distinct groups. This result supports the use of proof testing for structural validation. Static design allowables are derived based on the Weibull distribution. Fatigue data indicates no measured increase in specimen compliance prior to final fracture. All static and fatigue failures at room temperature dry conditions occurred catastrophically. The elliptical specimens demonstrated unusually high failure strengths indicating the presence of phenomena requiring further study. Results are also included for specimens exposed to a wet environment showing a matrix strength degradation due to moisture content. Further testing is underway to evaluate a fatigue methodology for matrix dominated failures based on residual static strength (wearout).

Thermal endurance tests on silicone rubber specimens

International Nuclear Information System (INIS)

Warburton, C.

1977-07-01

Thermal endurance tests have been performed on a range of silicone rubber specimens at temperature above 300 0 C. It is suggested that the rubber mix A2426, the compound from which Wylfa sealing rings are manufactured, will fail at temperatures above 300 0 C within weeks. Hardness measurements show that this particular rubber performs in a similar manner to Walker's S.I.L./60. (author)

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.

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

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.)

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

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

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

Comparison of gross anatomy test scores using traditional specimens vs. QuickTime Virtual Reality animated specimens

Science.gov (United States)

Maza, Paul Sadiri

movie modules. The comparison of the two sample group means of the examinations show that there was no difference in results between using QTVR movie modules to test gross anatomy knowledge versus using physical specimens. The results of this study are discussed to explain the benefits of using such computer based anatomy resources in gross anatomy assessments.

Acquisition and preparation of specimens of rock for large-scale testing

International Nuclear Information System (INIS)

Watkins, D.J.

1981-01-01

The techniques used for acquisition and preparation of large specimens of rock for laboratory testing depend upon the location of the specimen, the type of rock and the equipment available at the sampling site. Examples are presented to illustrate sampling and preparation techniques used for two large cylindrical samples of granitic material, one pervasively fractured and one containing a single fracture

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.

Computer vision applied to herbarium specimens of German trees: testing the future utility of the millions of herbarium specimen images for automated identification.

Science.gov (United States)

Unger, Jakob; Merhof, Dorit; Renner, Susanne

2016-11-16

Global Plants, a collaborative between JSTOR and some 300 herbaria, now contains about 2.48 million high-resolution images of plant specimens, a number that continues to grow, and collections that are digitizing their specimens at high resolution are allocating considerable recourses to the maintenance of computer hardware (e.g., servers) and to acquiring digital storage space. We here apply machine learning, specifically the training of a Support-Vector-Machine, to classify specimen images into categories, ideally at the species level, using the 26 most common tree species in Germany as a test case. We designed an analysis pipeline and classification system consisting of segmentation, normalization, feature extraction, and classification steps and evaluated the system in two test sets, one with 26 species, the other with 17, in each case using 10 images per species of plants collected between 1820 and 1995, which simulates the empirical situation that most named species are represented in herbaria and databases, such as JSTOR, by few specimens. We achieved 73.21% accuracy of species assignments in the larger test set, and 84.88% in the smaller test set. The results of this first application of a computer vision algorithm trained on images of herbarium specimens shows that despite the problem of overlapping leaves, leaf-architectural features can be used to categorize specimens to species with good accuracy. Computer vision is poised to play a significant role in future rapid identification at least for frequently collected genera or species in the European flora.

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.

Remote replacement of materials open-test assembly specimens at the FFTF/IEM cell

International Nuclear Information System (INIS)

Gibbons, P.W.; Ramsey, E.B.

1990-01-01

The Fast Flux Test Facility (FFTF) interim examination and maintenance (IEM) cell is used for the remote disassembly of irradiated fuel and materials experiments. The materials open-test assembly (MOTA) is brought to the IEM cell for materials test specimen removal. The specimens are shipped to the materials laboratory for sorting and installation in new specimen holders and then returned within 10 days to the IEM cell where they are installed in a new MOTA vehicle for further irradiation. Reconstituting a MOTA is a challenging remote operation involving dozens of steps and two separate facilities. Handling and disassembling sodium-wetted components pose interesting handling, cleaning, and disposal challenges. The success of this system is evidenced by its timely completion in the critical path of FFTF outage schedules

Surface crack growth in cylindrical hollow specimen subject to tension and torsion

Directory of Open Access Journals (Sweden)

V. Shlyannikov

2015-07-01

Full Text Available The subject for studies is an aluminium cylindrical hollow specimen with external axial and part circumferential semi-elliptical surface crack undergoing fatigue loads. Both the optical microscope measurements and the crack opening displacement (COD method are used to monitor and calculate both crack depth and crack length during the tests. The variation of crack growth behaviour is studied under cyclic axial tension, pure torsion and combined tension+torsion fatigue loading. For the particular surface flaw geometries considered, the elastic and plastic in-plane and out-of-plane constraint parameters, as well as the governing parameter for stress fields in the form of In-integral and plastic stress intensity factor, are obtained as a function of the aspect ratio, dimensionless crack length and crack depth. The combined effect of tension and torsion loading and initial surface flaw orientation on the crack growth for two type of aluminium alloys is made explicit. The experimental and numerical results of the present study provided the opportunity to explore the suggestion that fatigue crack propagation may be governed more strongly by the plastic stress intensity factor rather than the magnitude of the elastic SIFs alone. One advantage of the plastic SIF is its sensitivity to combined loading due to accounting for the plastic properties of the material.

Standard test method for laboratory evaluation of magnesium sacrificial anode test specimens for underground applications

CERN Document Server

American Society for Testing and Materials. Philadelphia

1997-01-01

1.1 This test method covers a laboratory procedure that measures the two fundamental performance properties of magnesium sacrificial anode test specimens operating in a saturated calcium sulfate, saturated magnesium hydroxide environment. The two fundamental properties are electrode (oxidation potential) and ampere hours (Ah) obtained per unit mass of specimen consumed. Magnesium anodes installed underground are usually surrounded by a backfill material that typically consists of 75 % gypsum (CaSO4·2H2O), 20 % bentonite clay, and 5 % sodium sulfate (Na2SO4). The calcium sulfate, magnesium hydroxide test electrolyte simulates the long term environment around an anode installed in the gypsum-bentonite-sodium sulfate backfill. 1.2 This test method is intended to be used for quality assurance by anode manufacturers or anode users. However, long term field performance properties may not be identical to property measurements obtained using this laboratory test. Note 1—Refer to Terminology G 15 for terms used ...

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....

Miniature specimen technology for postirradiation fatigue crack growth testing

International Nuclear Information System (INIS)

Mervyn, D.A.; Ermi, A.M.

1979-01-01

Current magnetic fusion reactor design concepts require that the fatigue behavior of candidate first wall materials be characterized. Fatigue crack growth may, in fact, be the design limiting factor in these cyclic reactor concepts given the inevitable presence of crack-like flaws in fabricated sheet structures. Miniature specimen technology has been developed to provide the large data base necessary to characterize irradiation effects on the fatigue crack growth behavior. An electrical potential method of measuring crack growth rates is employed on miniature center-cracked-tension specimens (1.27 cm x 2.54 cm x 0.061 cm). Results of a baseline study on 20% cold-worked 316 stainless steel, which was tested in an in-cell prototypic fatigue machine, are presented. The miniature fatigue machine is designed for low cost, on-line, real time testing of irradiated fusion candidate alloys. It will enable large scale characterization and development of candidate first wall alloys

Analysis of the percentage voids of test and field specimens using computerized tomography

International Nuclear Information System (INIS)

Braz, D.; Lopes, R.T.; Motta, L.M.G. da

1999-01-01

Computerized tomography has been an excellent tool of analysis of asphaltics mixtures, because it allows comparison of the quality and integrity of test and field specimens. It was required to detect and follow the evolution of cracks, when these mixtures were submitted to fatigue tests, and also helping to interpret the distribution of tensions and deformations which occur in the several types of solicitations imposed to the mixtures. Comparing the medium values of percentage voids obtained from tomographic images with the project's values, it can be observed that the values of test and field specimens for the wearing course are closer to the ones of the project than the ones of the binder. It can be verified that the wearing course specimens always present a distribution of the aggregate, and voids quite homogeneously in the whole profile of the sample, while the binder specimens show an accentuated differentiation of the same factors in the several heights of the sample. Therefore, when choosing a slice for tomography, these considerations should be taken into account

Corrosion testing of uranium silicide fuel specimens

International Nuclear Information System (INIS)

Bourns, W.T.

1968-09-01

U 3 Si is the most promising high density natural uranium fuel for water-cooled power reactors. Power reactors fuelled with this material are expected to produce cheaper electricity than those fuelled with uranium dioxide. Corrosion tests in 300 o C water preceded extensive in-reactor performance tests of fuel elements and bundles. Proper heat-treatment of U-3.9 wt% Si gives a U 3 5i specimen which corrodes at less than 2 mg/cm 2 h in 300 o C water. This is an order of magnitude lower than the maximum corrosion rate tolerable in a water-cooled reactor. U 3 Si in a defected unbonded Zircaloy-2 sheath showed only a slow uniform sheath expansion in 300 o C water. All tests were done under isothermal conditions in an out-reactor loop. (author)

Corrosion testing of uranium silicide fuel specimens

Energy Technology Data Exchange (ETDEWEB)

Bourns, W T

1968-09-15

U{sub 3}Si is the most promising high density natural uranium fuel for water-cooled power reactors. Power reactors fuelled with this material are expected to produce cheaper electricity than those fuelled with uranium dioxide. Corrosion tests in 300{sup o}C water preceded extensive in-reactor performance tests of fuel elements and bundles. Proper heat-treatment of U-3.9 wt% Si gives a U{sub 3}5i specimen which corrodes at less than 2 mg/cm{sup 2} h in 300{sup o}C water. This is an order of magnitude lower than the maximum corrosion rate tolerable in a water-cooled reactor. U{sub 3}Si in a defected unbonded Zircaloy-2 sheath showed only a slow uniform sheath expansion in 300{sup o}C water. All tests were done under isothermal conditions in an out-reactor loop. (author)

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.

Standard practice for preparation and use of Bent-Beam stress-corrosion test specimens

CERN Document Server

American Society for Testing and Materials. Philadelphia

2011-01-01

1.1 This practice covers procedures for designing, preparing, and using bent-beam stress-corrosion specimens. 1.2 Different specimen configurations are given for use with different product forms, such as sheet or plate. This practice applicable to specimens of any metal that are stressed to levels less than the elastic limit of the material, and therefore, the applied stress can be accurately calculated or measured (see Note 1). Stress calculations by this practice are not applicable to plastically stressed specimens. Note 1—It is the nature of these practices that only the applied stress can be calculated. Since stress-corrosion cracking is a function of the total stress, for critical applications and proper interpretation of results, the residual stress (before applying external stress) or the total elastic stress (after applying external stress) should be determined by appropriate nondestructive methods, such as X-ray diffraction (1). 1.3 Test procedures are given for stress-corrosion testing by ex...

Development of resistance welding process. 4. Preparation of pressuring enclosed creep test specimen of 7A material

International Nuclear Information System (INIS)

Endo, Hideo; Seki, Masayuki; Ishibashi, Fujio; Hirako, Kazuhito; Tsukada, Tatsuya

2001-02-01

Mechanical strength in the position welded by resistance welding system was examined in 1999. The test specimens were destroyed in the welding position in a shorter time than expected in the creep test. Therefore, test specimens were prepared to evaluate the cause of destruction. Inner-pressure enclosed creep test specimens were prepared by resistance welding method. Cladding material with low deviation of thickness and high re-crystallization rate was used. Heat treatment after resistance welding was performed to remove the influence of residual stress and the precipitation of carbides. (1) Before preparation of specimens, the welding condition was fixed. Three test specimens were prepared. Two specimens without heat treatment were transported to MMS in Oarai Engineering Center on Aug. 4, 2000. One specimen with heat treatment was transported to MMS after evaluating the residual stress to get optimum heat treatment condition. (2) Specimens were prepared with welding end plugs to both ends of ferritic ODS cladding. Enclosing sides were welded with highly strong Ferritic/Martensitic steel end plugs. The other sides were welded with ferritic ODS end plugs. (3) Some kinds of electrical wave data were obtained during performing welding. Welding position was evaluated with supersonic detector after performing welding. (4) Mechanical strength of welding position in high temperature 800degC was confirmed to be equal to or larger than that of cladding material. The highly qualified specimens in the present were successfully prepared. (author)

Critical assessment of precracked specimen configuration and experimental test variables for stress corrosion testing of 7075-T6 aluminum alloy plate

Science.gov (United States)

Domack, M. S.

1985-01-01

A research program was conducted to critically assess the effects of precracked specimen configuration, stress intensity solutions, compliance relationships and other experimental test variables for stress corrosion testing of 7075-T6 aluminum alloy plate. Modified compact and double beam wedge-loaded specimens were tested and analyzed to determine the threshold stress intensity factor and stress corrosion crack growth rate. Stress intensity solutions and experimentally determined compliance relationships were developed and compared with other solutions available in the literature. Crack growth data suggests that more effective crack length measurement techniques are necessary to better characterize stress corrosion crack growth. Final load determined by specimen reloading and by compliance did not correlate well, and was considered a major source of interlaboratory variability. Test duration must be determined systematically, accounting for crack length measurement resolution, time for crack arrest, and experimental interferences. This work was conducted as part of a round robin program sponsored by ASTM committees G1.06 and E24.04 to develop a standard test method for stress corrosion testing using precracked specimens.

Charpy impact test of oxidized and hydrogenated zircaloy using a thin strip specimen

International Nuclear Information System (INIS)

Otsuka, Teppei; Hashizume, Kenichi; Sugisaki, Masayasu

2004-01-01

The impact properties of an oxidized and a hydrogenated Zircaloy have been studied with an instrumented Charpy machine by using a strip Charpy V-notch specimen (1 mm thick by 4mm wide). Fracture processes such as crack initiation and propagation were examined using load-displacement curves obtained in this study. In the case of the hydrogenated specimen containing preferentially oriented hydrides, an appreciable decrease in the absorbed energy was observed in the crack propagation rather than in the crack initiation. From results of fractographs of the specimen, it was suggested that the reduction of the crack propagation energy of hydrogenated specimen could be attributed to the change of the stress state in the Zircaloy matrix, which was caused by the fracture of hydride in the inner part of specimen. In the case of the specimen oxidized at 973k for 60 min, on which an oxide layer (4 μm in thickness) and oxygen incursion layer (4μm) were formed, the surface layers affected the crack initiation process. The growing oxygen incursion layer, in particular, resulted in the constraint of plastic deformation of the Zircaloy matrix not only in the crack initiation but also in the crack propagation as its thickness increased. (author)

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

Stress Wave Attenuation in Aluminum Alloy and Mild Steel Specimens Under SHPB Tensile Testing

Science.gov (United States)

Pothnis, J. R.; Ravikumar, G.; Arya, H.; Yerramalli, Chandra S.; Naik, N. K.

2018-02-01

Investigations on the effect of intensity of incident pressure wave applied through the striker bar on the specimen force histories and stress wave attenuation during split Hopkinson pressure bar (SHPB) tensile testing are presented. Details of the tensile SHPB along with Lagrangian x- t diagram of the setup are included. Studies were carried out on aluminum alloy 7075 T651 and IS 2062 mild steel. While testing specimens using the tensile SHPB setup, it was observed that the force calculated from the transmitter bar strain gauge was smaller than the force obtained from the incident bar strain gauge. This mismatch between the forces in the incident bar and the transmitter bar is explained on the basis of stress wave attenuation in the specimens. A methodology to obtain force histories using the strain gauges on the specimen during SHPB tensile testing is also presented. Further, scanning electron microscope images and photomicrographs are given. Correlation between the microstructure and mechanical properties is explained. Further, uncertainty analysis was conducted to ascertain the accuracy of the results.

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

International Nuclear Information System (INIS)

Nanstad, R.K.

1980-01-01

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

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.

Quantitative estimation of hydrogen concentration on the Ni3Al specimens surface in the process of hydrogen release

International Nuclear Information System (INIS)

Katano, Gen; Sano, Shogo; Saito, Hideo; Mori, Minoru

2000-01-01

The method to calculate the hydrogen concentration in metal specimens is given by tritium counts with the liquid scintillation counter. As segments to measure, Ni 3 Al intermetallic compound crystals were used. Tritium was charged to crystals with the method of cathode charging. The charged tritium was transported by diffusion and released from specimen surface. The tritium releasing rate was calculated from the increasing rate of tritium activity. Then the concentration of hydrogen at the surface was calculated from tritium counts. The outcome showed that the hydrogen concentration decreases at specimens surface by elapsed time. Then, the behavior of tritium diffusion was affected by doped boron (up to 0.235 atom% B and 0.470 atom% B) in Ni 3 Al crystals. As the amount of boron increased, the tritium diffusion coefficient decreased. And the hydrogen concentration varied with the amount of boron. After passing enough time, the hydrogen concentration in crystals with boron was much larger than the one without boron. Since it is very likely that the hydrogen concentration is affected by the number of hydrogen sites in the crystal, it is obvious judging by these phenomena, that by doping boron, numbers of hydrogen trapping sites were created. As the hydrogen distribution becomes homogenous after passing enough time, it is possible to measure the hydrogen concentration in all the crystals from β-ray counts at specimens surface. (author)

C.O.D. toughness testing of medium strength steel as a preliminary development for single specimen J integral toughness tests of SA533-B steel

International Nuclear Information System (INIS)

Dean, P.; Tait, R.B.; Garrett, G.G.

1981-10-01

The primary purpose of this project is to set up a test facility and to develop the necessary expertise to enable reliable elasto-plastic fracture toughness tests to be performed. Initially, tests are to be conducted on material similar to that used in the Koeberg pressure vessel walls, with the ultimate goal of performing single specimen J integral tests on the pressure vessel steel itself to determine through-thickness toughness variations. The project will comprise a number of stages, each one necessary for the development of the techniques used in J integral testing. These include: (i) development of an appropriate specimen design, of suitable size and shape that is applicable to both crack opening displacement (C.O.D.) and J integral tests; (ii) development, testing and calibration of the necessary associated mechanical and electrical equipment (e.g. clip gauge, amplifiers, interface unit, etc.), with (iii) an estimation of the probable errors and noise levels with a view to their elimantion, leading to (iv) perfection of the sensitivity and reproducibility of, firstly, the multiple specimen C.O.D. technique and, secondly, the multiple specimen J integral techniques. (v) Based on the above techniques, development of the single specimen J integral test method incorporating development of a computerised testing procedure. All the above procedure is to be conducted on similar, but non-Koeberg pressure vessel material ('ROQ Tough'). (vi) Finally, development and testing of both multiple specimen and single specimen J integral tests on actual SA533B material and an investigation of the through thickness toughness and fatigue crack propagation behaviour

New specimen design for studying the growth of small fatigue cracks with surface acoustic waves

Science.gov (United States)

London, Blair

1985-08-01

The study of small surface fatigue cracks in AISI 4140 quenched and tempered steel by a nondestructive surface acoustic wave technique is summarized. A novel cantilevered bending, plate-type fatigue specimen is described that is compatible with the acoustic method. Small cracks are initiated from a 25-μm deep surface pit produced by an electrospark machine. The importance of studying these cracks which closely approximate naturally occurring fatigue cracks is briefly discussed.

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.

Design of creep machine and creep specimen chamber for carrying out creep tests in flowing liquid sodium

Energy Technology Data Exchange (ETDEWEB)

Ravi, S., E-mail: sravi@igcar.gov.in; Laha, K.; Sakthy, S.; Mathew, M.D.; Jayakumar, T.

2014-02-15

Highlights: • Design of a lever type creep machine for carrying out creep test in flowing sodium. • Leveling of lever during creep was achieved by automated movement of fulcrum. • Design of creep chamber for providing constant sodium flow rate across creep specimen. • Minimum use of bellow in chamber for sodium containment and mechanical isolation. • Mini-lever mechanism to counter balance load reduction on specimen due to bellow stiffness. - Abstract: A creep testing system has been designed, fabricated, installed and validated for carrying out creep tests in flowing liquid sodium. The testing system consists of two sections namely creep testing machine and an environmental chamber. The testing system has the ability of (i) applying tensile load to the test specimen through a lever, (ii) monitoring continuously the creep elongation and (iii) allowing sodium to flow around the creep specimen at constant velocity. The annular space between the creep specimen and the environmental chamber has been suitably designed to maintain constant sodium flow velocity. Primary and secondary bellows are employed in the environmental chamber to (i) mechanically isolate the creep specimen, (ii) prevent the flowing sodium in contact with air and (iii) maintain an argon gas cover to the leaking sodium if any from primary bellow, with a provision to an alarm get activated by a spark plug. The lever-horizontality during creep test has been maintained by automatically lifting up the fulcrum instead of lowering down the pull rod as conventionally used. A mini lever mechanism has been incorporated in the load train to counter balance the load reduction on specimen from the changing stiffness of the bellows. The validation of the testing system has been established by carrying out creep tests on 316L(N) stainless steel at 873 K over a wide stress range and comparing the results with those obtained in air by employing the developed and conventional creep testing machines.

Failure mechanism of resistance-spot-welded specimens impacted on base material by bullets

Science.gov (United States)

Fan, Chunlei; Ma, Bohan; Chen, Danian; Wang, Huanran; Ma, Dongfang

2018-01-01

The tests of bullet impact on the base material (BM) of a simple specimen with a single resistance-spot-welded (RSW) nugget of TRIP800 steel are performed to investigate the response of the RSW specimen to the ballistic debris impact on the RSW specimen. A one-stage gas gun is used to fire the bullets while a laser velocity interferometer system for any reflector (VISAR) is used to measure the velocity histories of the free surfaces of the RSW specimen. The recovered RSW specimens are examined with the three-dimensional super depth digital microscope (SDDM) and the scanning electro microscope (SEM). For the tests of small multiple-bullet impact, it is revealed that the wave train of the VISAR measured results and the detachment of the base material interfaces in the recovered RSW specimens are directly related to the reflection and refraction of the curved stress waves incoming to the interfaces and the free surfaces in the RSW specimens. The detachment of BM interfaces can lead to the impact failure of the RSW joints for the larger multiple-bullet impact at higher velocity, the mechanism of which is different from the case for normal incidence (spalling). For the tests of single large bullet impact, it is brought to light experimentally that the plastic strain concentration at the "notch tip" spurs either the crack near the RSW joint or the split of the nugget. The numerical simulation shows up the process of splitting the nugget: a crack initiates at the "notch tip", propagates across the nugget interface and splits the nugget into two parts. It is indicated that the interaction between the stress waves and many interfaces/free surfaces in the RSW specimen under ballistic impact causes variable local stress triaxialities and stress Lode angles, which affects the deformation and fracture mechanism of the RSW specimen including stretching and shearing failure. It is shown that the impact failure of the RSW joints is a mixture of brittle fracture and ductile

Environmental charging of spacecraft-tests of thermal control materials for use on the global positioning system flight space vehicle. Part 2: Specimen 6 to 9

Science.gov (United States)

Stevens, N. J.; Berkopec, F. D.; Blech, R. A.

1976-01-01

The NASA/USAF program on the Environmental Charging of Spacecraft Surfaces consists, in part, of experimental efforts directed toward evaluating the response of materials to the environmental charged particle flux. Samples of thermal blankets of the type to be used on the Global Positioning System Flight Space Vehicles were tested to determine their response to electron flux. The primary result observed was that no discharges were obtained with the quartz-fiber-fabric-covered multilayer insulation specimen. The taped aluminized polyester grounding system used on all specimens did not appear to grossly deteriorate with time; however, the specimens require specific external pressure to maintain constant grounding system resistance.

Stress corrosion cracking tests on electron beam welded carbon steel specimens in carbonate-bicarbonate solution

International Nuclear Information System (INIS)

Parkins, R.N.

1985-04-01

Stress corrosion cracking tests have been performed on tapered carbon steel test pieces containing electron beam welds with a view to defining susceptibility to such cracking in a carbonate-bicarbonate solution at 90 C and an appropriate electrode potential. The tests involved applying cyclic loads to the specimens and it is shown that the threshold stress for cracking reduces linearly with increase in the magnitude of the cyclic load component. Extrapolation of these trends to zero fluctuating stress indicates static load threshold stresses in the vicinity of the yield stress (i.e. about 300 N/mm 2 for parent plate without a weld, 400 N/mm 2 for specimens with welds on one side only and 600 N/mm 2 for specimens having welds penetrating through the thickness of the specimen). The averages of the maximum crack velocities observed were least for parent plate material and greatest for weld metal, the former being essentially intergranular in morphology and the latter mostly transgranular, with heat affected zone material being intermediate between these extremes. (author)

49 CFR 40.99 - How long does the laboratory retain specimens after testing?

Science.gov (United States)

2010-10-01

... 49 Transportation 1 2010-10-01 2010-10-01 false How long does the laboratory retain specimens after testing? 40.99 Section 40.99 Transportation Office of the Secretary of Transportation PROCEDURES FOR TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Drug Testing Laboratories § 40.99 How...

Disturbance induced by surface preparation on instrumented indentation test

International Nuclear Information System (INIS)

Li, Yugang; Kanouté, Pascale; François, Manuel

2015-01-01

Surface preparation, which may induce considerable sample disturbance, plays an important role in instrumented indentation test (IIT). In this study, the sample disturbance (mainly divided into residual stresses and plastic strain) induced by the surface preparation process of instrumented indentation test specimens were investigated with both experimental tests and numerical simulations. Grazing incidence X-ray diffractions (GIXRD) and uniaxial tensile tests were conducted for characterizing the residual stresses and high plastic strain in the top surface layers of a carefully mechanically polished indentation sample, which, in the present work, is made of commercially pure titanium. Instrumented indentation tests and the corresponding finite element simulations were performed as well. For comparison, a reference sample (carefully mechanically polished & electrolytically polished) which represents the raw material was prepared and tested. Results showed that a careful mechanical polishing procedure can effectively reduce the level of residual stresses induced by this process. However, the high plastic strain in the surface region imposed by the polishing process is significant. The induced plastic strain can affect a depth up to 5 µm, which is deeper than the maximum penetration depth h max (3 µm) used for the instrumented indentation tests. In the near surface layer (in the range of depth about 350 nm), the plastic strain levels are fairly high. In the very top layer, the plastic strain was even estimated to reach more than 60%. The simultaneous use of indentation tests and numerical simulations showed that the existence of high plastic strain in the surface region will make the load vs depth (P–h) curve shift upwards, the contact hardness (H) increase and the contact stiffness (S) decrease

Disturbance induced by surface preparation on instrumented indentation test

Energy Technology Data Exchange (ETDEWEB)

Li, Yugang, E-mail: yugang.li@utt.fr [Université de Technologie de Troyes (UTT), ICD-LASMIS, UMR CNRS 6281, 12, rue Marie Curie-CS 42060, 10010 Troyes Cedex (France); Kanouté, Pascale, E-mail: pascale.kanoute@onera.fr [Université de Technologie de Troyes (UTT), ICD-LASMIS, UMR CNRS 6281, 12, rue Marie Curie-CS 42060, 10010 Troyes Cedex (France); The French Aerospace Lab (ONERA), DMSM/MCE, 29 avenue de la Division Leclerc-BP 72, F-92322 Chatillon Cedex (France); François, Manuel, E-mail: manuel.francois@utt.fr [Université de Technologie de Troyes (UTT), ICD-LASMIS, UMR CNRS 6281, 12, rue Marie Curie-CS 42060, 10010 Troyes Cedex (France)

2015-08-26

Surface preparation, which may induce considerable sample disturbance, plays an important role in instrumented indentation test (IIT). In this study, the sample disturbance (mainly divided into residual stresses and plastic strain) induced by the surface preparation process of instrumented indentation test specimens were investigated with both experimental tests and numerical simulations. Grazing incidence X-ray diffractions (GIXRD) and uniaxial tensile tests were conducted for characterizing the residual stresses and high plastic strain in the top surface layers of a carefully mechanically polished indentation sample, which, in the present work, is made of commercially pure titanium. Instrumented indentation tests and the corresponding finite element simulations were performed as well. For comparison, a reference sample (carefully mechanically polished & electrolytically polished) which represents the raw material was prepared and tested. Results showed that a careful mechanical polishing procedure can effectively reduce the level of residual stresses induced by this process. However, the high plastic strain in the surface region imposed by the polishing process is significant. The induced plastic strain can affect a depth up to 5 µm, which is deeper than the maximum penetration depth h{sub max} (3 µm) used for the instrumented indentation tests. In the near surface layer (in the range of depth about 350 nm), the plastic strain levels are fairly high. In the very top layer, the plastic strain was even estimated to reach more than 60%. The simultaneous use of indentation tests and numerical simulations showed that the existence of high plastic strain in the surface region will make the load vs depth (P–h) curve shift upwards, the contact hardness (H) increase and the contact stiffness (S) decrease.

Development of reconstitution technique of irradiated specimen. 2. Annual report for FY1994 on JAERI-IHI cooperated research program

Energy Technology Data Exchange (ETDEWEB)

Nishiyama, Yutaka; Fukaya, Kiyoshi; Onizawa, Kunio; Suzuki, Masahide; Shibata, Katsuyuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kaihara, Shoichiro; Nakamura, Terumi; Sato, Akira; Yoshida, Kazuo

1996-02-01

A surface-activated joining method to construct Charpy impact specimens from a limited volume of broken specimens is being developed. The method is likely to decrease the thermal input led to annealing and metallurgical changes. This paper describes the technical qualification process of the joining parameters and surface configuration of joined specimens. All tests have been done with A533B cl.1. The joining machine with higher vacuum than that previously used was prepared for the tests. Precise control of joining parameters led to heat-affected zone as small as 1mm in each side. In the case of joining the square shaped (10x10mm) and circular shaped ({phi} 16mm) specimens, overall joining was achieved by an attached envelope to the square shaped specimen. In addition, the grooved surface of the circular shaped specimen brought out uniformly distributed heat-affected zone. The specification of hot-use joining machine which involves the joining sequence and restrictions of the dimension was also examined. (author).

Conversion of fracture toughness testing values from small scale three point bending test specimens to small scale yielding state (SSY) by elastic-plastic stress analysis

International Nuclear Information System (INIS)

Ikonen, K.

1993-07-01

The report describes the work performed for achieving readiness to calculate fracture toughness dependence on dimension effects and loading conditions in fracture test specimens and real structures. In the report two- and three-dimensional computer codes developed and calculational methods applied are described. One of the main goals is to converse fracture toughness from small scale three point bending test specimens to case of a depth crack in plane strain i.e. to small scale yielding state (SSY) by numerical elastic-plastic stress analysis. Thickness effect of a test specimens and effect of a crack depth are separately investigated. Tests of three point bending specimens with and without sidegrooves and curved crack front are numerically simulated and experimental and computed results are compared. J-integral is calculated along crack front and also from force-deflection dependence of the beam. For the analyses the computing system was thoroughly automatized. Measuring capacity of three point bending test specimens was tried to evaluate. (orig.) (7 refs., 54 figs.)

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.

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.

COMPARISON BETWEEN WOOD DRYING DEFECT SCORES: SPECIMEN TESTING X ANALYSIS OF KILN-DRIED BOARDS

Directory of Open Access Journals (Sweden)

Djeison Cesar Batista

2015-04-01

Full Text Available It is important to develop drying technologies for Eucalyptus grandis lumber, which is one of the most planted species of this genus in Brazil and plays an important role as raw material for the wood industry. The general aim of this work was to assess the conventional kiln drying of juvenile wood of three clones of Eucalyptus grandis. The specific aims were to compare the behavior between: i drying defects indicated by tests with wood specimens and conventional kiln-dried boards; and ii physical properties and the drying quality. Five 11-year-old trees of each clone were felled, and only flatsawn boards of the first log were used. Basic density and total shrinkage were determined, and the drying test with wood specimens at 100 °C was carried out. Kiln drying of boards was performed, and initial and final moisture content, moisture gradient in thickness, drying stresses and drying defects were assessed. The defect scoring method was used to verify the behavior between the defects detected by specimen testing and the defects detected in kiln-dried boards. As main results, the drying schedule was too severe for the wood, resulting in a high level of boards with defects. The behavior between the defects in the drying test with specimens and the defects of kiln-dried boards was different, there was no correspondence, according to the defect scoring method.

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

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

Development of test specimens to obtain the transmission factors to attenuate photons of 0.511 MeV

International Nuclear Information System (INIS)

Costa, Jacó Júlio de Souza; Cardoso, Domingos D'Oliveira; Gavazza, Sérgio; Oliveira, Cláudio Luiz de; Morales, Rudnei Karam; Amorim, Aneuri Souza de; Balthar, Mario Cesar Viegas; Oliveira, Luciano Santa Rita

2017-01-01

For designing a shielding, it is necessary, mainly, to determine or have access to the following parameters: transmission factors of the material used and type of radiation to be shielded. Cylindrical test specimens with different thicknesses were developed for experimentally obtaining the material transmission factor for shielding calculation. The cylindrical test specimens were made considering the geometric characteristics of the detector, the ease of production and the energy of 0.511 MeV from the 18 F-FDG decay. A type of concrete widely used in Brazil was used in the preparation of the cylindrical test specimens. (author)

Development of test specimens to obtain the transmission factors to attenuate photons of 0.511 MeV

Energy Technology Data Exchange (ETDEWEB)

Costa, Jacó Júlio de Souza; Cardoso, Domingos D' Oliveira; Gavazza, Sérgio; Oliveira, Cláudio Luiz de; Morales, Rudnei Karam, E-mail: jacojulio@gmail.com [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil); Amorim, Aneuri Souza de; Balthar, Mario Cesar Viegas; Oliveira, Luciano Santa Rita [Centro Tecnológico do Exercito (CETEx), Rio de Janeiro, RJ (Brazil)

2017-07-01

For designing a shielding, it is necessary, mainly, to determine or have access to the following parameters: transmission factors of the material used and type of radiation to be shielded. Cylindrical test specimens with different thicknesses were developed for experimentally obtaining the material transmission factor for shielding calculation. The cylindrical test specimens were made considering the geometric characteristics of the detector, the ease of production and the energy of 0.511 MeV from the {sup 18}F-FDG decay. A type of concrete widely used in Brazil was used in the preparation of the cylindrical test specimens. (author)

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.

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

Standard test methods for bend testing of material for ductility

CERN Document Server

American Society for Testing and Materials. Philadelphia

2009-01-01

1.1 These test methods cover bend testing for ductility of materials. Included in the procedures are four conditions of constraint on the bent portion of the specimen; a guided-bend test using a mandrel or plunger of defined dimensions to force the mid-length of the specimen between two supports separated by a defined space; a semi-guided bend test in which the specimen is bent, while in contact with a mandrel, through a specified angle or to a specified inside radius (r) of curvature, measured while under the bending force; a free-bend test in which the ends of the specimen are brought toward each other, but in which no transverse force is applied to the bend itself and there is no contact of the concave inside surface of the bend with other material; a bend and flatten test, in which a transverse force is applied to the bend such that the legs make contact with each other over the length of the specimen. 1.2 After bending, the convex surface of the bend is examined for evidence of a crack or surface irregu...

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

Test and Analysis Correlation for a Y-Joint Specimen for a Composite Cryotank

Science.gov (United States)

Mason, Brian H.; Sleight, David W.; Grenoble, Ray

2015-01-01

The Composite Cryotank Technology Demonstration (CCTD) project under NASA's Game Changing Development Program (GCDP) developed space technologies using advanced composite materials. Under CCTD, NASA funded the Boeing Company to design and test a number of element-level joint specimens as a precursor to a 2.4-m diameter composite cryotank. Preliminary analyses indicated that the y-joint in the cryotank had low margins of safety; hence the y-joint was considered to be a critical design region. The y-joint design includes a softening strip wedge to reduce localized shear stresses at the skirt/dome interface. In this paper, NASA-developed analytical models will be correlated with the experimental results of a series of positive-peel y-joint specimens from Boeing tests. Initial analytical models over-predicted the experimental strain gage readings in the far-field region by approximately 10%. The over-prediction was attributed to uncertainty in the elastic properties of the laminate and a mismatch between the thermal expansion of the strain gages and the laminate. The elastic properties of the analytical model were adjusted to account for the strain gage differences. The experimental strain gages also indicated a large non-linear effect in the softening strip region that was not predicted by the analytical model. This non-linear effect was attributed to delamination initiating in the softening strip region at below 20% of the failure load for the specimen. Because the specimen was contained in a thermally insulated box during cryogenic testing to failure, delamination initiation and progression was not visualized during the test. Several possible failure initiation locations were investigated, and a most likely failure scenario was determined that correlated well with the experimental data. The most likely failure scenario corresponded to damage initiating in the softening strip and delamination extending to the grips at final failure.

Apparatus and method for fatigue testing of a material specimen in a high-pressure fluid environment

Science.gov (United States)

Wang, Jy-An; Feng, Zhili; Anovitz, Lawrence M; Liu, Kenneth C

2013-06-04

The invention provides fatigue testing of a material specimen while the specimen is disposed in a high pressure fluid environment. A specimen is placed between receivers in an end cap of a vessel and a piston that is moveable within the vessel. Pressurized fluid is provided to compression and tension chambers defined between the piston and the vessel. When the pressure in the compression chamber is greater than the pressure in the tension chamber, the specimen is subjected to a compression force. When the pressure in the tension chamber is greater than the pressure in the compression chamber, the specimen is subjected to a tension force. While the specimen is subjected to either force, it is also surrounded by the pressurized fluid in the tension chamber. In some examples, the specimen is surrounded by hydrogen.

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

Energy Technology Data Exchange (ETDEWEB)

Lucon, E

1999-04-01

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

Metallographic analysis of irradiated RERTR-3 fuel test specimens

International Nuclear Information System (INIS)

Meyer, M. K.; Hofman, G. L.; Strain, R. V.; Clark, C. R.; Stuart, J. R.

2000-01-01

The RERTR-3 irradiation test was designed to investigate the irradiation behavior of aluminum matrix U-MO alloy dispersion fuels under high-temperature, high-fission-rate conditions. Initial postirradiation examination of RERTR-3 fuel specimens has concentrated on binary U-MO atomized fuels. The rate of matrix aluminum depletion was found to be higher than predictions based on low temperature irradiation data. Wavelength Dispersive X-ray Spectroscopy (WDS) indicates that aluminum is present in the interior of the fuel particles. WDS data is supported by a mass and volume balance calculation performed on the basis of image analysis results. The depletion of matrix aluminum seems to have no detrimental effects on fuel performance under the conditions tested to date

Fatigue damage observed non-destructively in fibre composite coupon test specimens by X-ray CT

DEFF Research Database (Denmark)

Jespersen, Kristine Munk; Mikkelsen, Lars Pilgaard

2016-01-01

This study presents a method for monitoring the 3D fatigue damage progression on a micro-structural level in a glass fibre/polymer coupon test specimen by means of laboratory X-ray Computed Tomography (CT). A modified mount and holder made for the standard test samples to fit into the X-ray CT...... scanner along with a tension clamp solution is presented. Initially, the same location of the test specimen is inspected by ex-situ X-ray CT during the fatigue loading history, which shows the damage progression on a micro-structural level. The openings of individual uni-directional (UD) fibre fractures...

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.)

Failure mechanism of resistance-spot-welded specimens impacted on base material by bullets

Directory of Open Access Journals (Sweden)

Chunlei Fan

2018-01-01

Full Text Available The tests of bullet impact on the base material (BM of a simple specimen with a single resistance-spot-welded (RSW nugget of TRIP800 steel are performed to investigate the response of the RSW specimen to the ballistic debris impact on the RSW specimen. A one-stage gas gun is used to fire the bullets while a laser velocity interferometer system for any reflector (VISAR is used to measure the velocity histories of the free surfaces of the RSW specimen. The recovered RSW specimens are examined with the three-dimensional super depth digital microscope (SDDM and the scanning electro microscope (SEM. For the tests of small multiple-bullet impact, it is revealed that the wave train of the VISAR measured results and the detachment of the base material interfaces in the recovered RSW specimens are directly related to the reflection and refraction of the curved stress waves incoming to the interfaces and the free surfaces in the RSW specimens. The detachment of BM interfaces can lead to the impact failure of the RSW joints for the larger multiple-bullet impact at higher velocity, the mechanism of which is different from the case for normal incidence (spalling. For the tests of single large bullet impact, it is brought to light experimentally that the plastic strain concentration at the “notch tip” spurs either the crack near the RSW joint or the split of the nugget. The numerical simulation shows up the process of splitting the nugget: a crack initiates at the “notch tip”, propagates across the nugget interface and splits the nugget into two parts. It is indicated that the interaction between the stress waves and many interfaces/free surfaces in the RSW specimen under ballistic impact causes variable local stress triaxialities and stress Lode angles, which affects the deformation and fracture mechanism of the RSW specimen including stretching and shearing failure. It is shown that the impact failure of the RSW joints is a mixture of brittle

Estimation of Surface Temperature and Heat Flux by Inverse Heat Transfer Methods Using Internal Temperatures Measured While Radiantly Heating a Carbon/Carbon Specimen up to 1920 F

Science.gov (United States)

Pizzo, Michelle; Daryabeigi, Kamran; Glass, David

2015-01-01

The ability to solve the heat conduction equation is needed when designing materials to be used on vehicles exposed to extremely high temperatures; e.g. vehicles used for atmospheric entry or hypersonic flight. When using test and flight data, computational methods such as finite difference schemes may be used to solve for both the direct heat conduction problem, i.e., solving between internal temperature measurements, and the inverse heat conduction problem, i.e., using the direct solution to march forward in space to the surface of the material to estimate both surface temperature and heat flux. The completed research first discusses the methods used in developing a computational code to solve both the direct and inverse heat transfer problems using one dimensional, centered, implicit finite volume schemes and one dimensional, centered, explicit space marching techniques. The developed code assumed the boundary conditions to be specified time varying temperatures and also considered temperature dependent thermal properties. The completed research then discusses the results of analyzing temperature data measured while radiantly heating a carbon/carbon specimen up to 1920 F. The temperature was measured using thermocouple (TC) plugs (small carbon/carbon material specimens) with four embedded TC plugs inserted into the larger carbon/carbon specimen. The purpose of analyzing the test data was to estimate the surface heat flux and temperature values from the internal temperature measurements using direct and inverse heat transfer methods, thus aiding in the thermal and structural design and analysis of high temperature vehicles.

Analysis of anisotropic damage in forged Al–Cu–Mg–Si alloy based on creep tests, micrographs of fractured specimen and digital image correlations

Energy Technology Data Exchange (ETDEWEB)

Gariboldi, Elisabetta, E-mail: elisabetta.gariboldi@polimi.it [Politecnico di Milano, Department of Mechanical Engineering, Via La Masa 34 20156 Milano (Italy); Naumenko, Konstantin, E-mail: konstantin.naumenko@ovgu.de [Otto-von-Guericke-University Magdeburg, Institute of Mechanics, D-39106 Magdeburg (Germany); Ozhoga-Maslovskaja, Oksana, E-mail: oksana.ozhogamaslovskaja@gmail.com [Politecnico di Milano, Department of Mechanical Engineering, Via La Masa 34 20156 Milano (Italy); Zappa, Emanuele, E-mail: emanuele.zappa@polimi.it [Politecnico di Milano, Department of Mechanical Engineering, Via La Masa 34 20156 Milano (Italy)

2016-01-15

The aim of this paper is to analyze anisotropic damage mechanisms in forged Al–Cu–Mg–Si alloy based on the results of creep tests. Smooth specimens are sampled in three forging directions. Creep strain vs. time curves as well as light optical microscope and scanning electron microscope observations illustrate basic features of damage growth. Flat notch specimens are sampled in different directions to analyze stress redistributions and damage in zones of stress concentration. The digital image correlation technique has been applied in situ in order to extract the strain values on the surface of the notched specimens. All observations demonstrate that the principal origins of anisotropic creep and damage are associated with elongated grains and second phase clustered particles located at grain boundaries. Longitudinal specimens possess nucleations of decohesion sites and growth of voids around second phase particles at grain boundaries. Damage evolution for radial and transverse specimens is due to the formation and growth of cracks in second phase particles orthogonal to the principal stress axis. Residual strains are confined to the notch root as well as to the flanges of advanced macrocrack, indicating the small scale yielding during the creep fracture process.

An Experimental Study of Shear-Dominated Failure in the 2013 Sandia Fracture Challenge Specimen

Energy Technology Data Exchange (ETDEWEB)

Corona, Edmundo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Deibler, Lisa Anne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Reedlunn, Benjamin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ingraham, Mathew Duffy [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Williams, Shelley [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-04-01

This report presents an experimental study motivated by results obtained during the 2013 Sandia Fracture Challenge. The challenge involved A286 steel, shear-dominated compression specimens whose load-deflection response contained a load maximum fol- lowed by significant displacement under decreasing load, ending with a catastrophic fracture. Blind numerical simulations deviated from the experiments well before the maximum load and did not predict the failure displacement. A series of new tests were conducted on specimens machined from the original A286 steel stock to learn more about the deformation and failure processes in the specimen and potentially improve future numerical simulations. The study consisted of several uniaxial tension tests to explore anisotropy in the material, and a set of new tests on the compression speci- men. In some compression specimen tests, stereo digital image correlation (DIC) was used to measure the surface strain fields local to the region of interest. In others, the compression specimen was loaded to a given displacement prior to failure, unloaded, sectioned, and imaged under the microscope to determine when material damage first appeared and how it spread. The experiments brought the following observations to light. The tensile tests revealed that the plastic response of the material is anisotropic. DIC during the shear- dominated compression tests showed that all three in-plane surface strain components had maxima in the order of 50% at the maximum load. Sectioning of the specimens revealed no signs of material damage at the point where simulations deviated from the experiments. Cracks and other damage did start to form approximately when the max- imum load was reached, and they grew as the load decreased, eventually culminating in catastrophic failure of the specimens. In addition to the steel specimens, a similar study was carried out for aluminum 7075-T651 specimens. These specimens achieved much lower loads and displacements

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)

Progress in Tissue Specimens Alternative for the Driver Genes Testing of Non-small Cell Lung Cancer

Directory of Open Access Journals (Sweden)

Yan SUN

2015-06-01

Full Text Available Target treatment based on driver genes in advanced non-small cell lung cancer is very important currently. Tumor tissues is the gold standard for driver genes testing. However, most of patients could not get the gene information for lack of enough tissues. To explore the tissue specimens alternatives is a hot spot in clinical work. This report reviews the tissue specimen alternatives of driver gene testing in non-small cell lung cancer.

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...

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....

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.

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)

Standard Test Method to Determine Color Change and Staining Caused by Aircraft Maintenance Chemicals upon Aircraft Cabin Interior Hard Surfaces

CERN Document Server

American Society for Testing and Materials. Philadelphia

2001-01-01

1.1 This test method covers the determination of color change and staining from liquid solutions, such as cleaning or disinfecting chemicals or both, on painted metallic surfaces and nonmetallic surfaces of materials being used inside the aircraft cabin. The effects upon the exposed specimens are measured with the AATCC Gray Scale for Color Change and AATCC Gray Color Scale for Staining. Note 1—This test method is applicable to any colored nonmetallic hard surface in contact with liquids. The selected test specimens are chosen because these materials are present in the majority of aircraft cabin interiors. 1.2This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Macro and Microscopic Investigation on Fracture Specimen of Alloy 617 Base Metal and Weldment in Low Cycle Fatigue Regime

International Nuclear Information System (INIS)

Kim, Seon Jin; Dewa, Rando Tungga; Kim, Won Gon

2016-01-01

This paper investigates macro- and microscopic fractography performed on fracture specimens from low cycle fatigue (LCF) testings through an Alloy 617 base metal and weldments. The weldment specimens were taken from gas tungsten arc welding (GTAW) pad of Alloy 617. The aim of the present study is to investigate the macro- and microscopic aspects of the low cycle fatigue fracture mode and mechanism of Alloy 617 base metal and GTAWed weldment specimens. Fully axial total strain controlled fatigue tests were conducted at room temperature with total strain ranges of 0.6, 0.9, 1.2 and 1.5%. Macroscopic fracture surfaces of Alloy 617 base metal specimens showed a flat type normal to the fatigue loading direction, whereas the GTAWed weldment specimens were of a shear/star type. The fracture surfaces of both the base metal and weldment specimens revealed obvious fatigue striations at the crack propagation regime. In addition, the fatigue crack mechanism of the base metal showed a transgranular normal to fatigue loading direction; however, the GTAWed weldment specimens showed a transgranular at approximately 45° to the fatigue loading direction

Macro and Microscopic Investigation on Fracture Specimen of Alloy 617 Base Metal and Weldment in Low Cycle Fatigue Regime

Energy Technology Data Exchange (ETDEWEB)

Kim, Seon Jin; Dewa, Rando Tungga [Pukyung National Univ., Busan (Korea, Republic of); Kim, Won Gon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-06-15

This paper investigates macro- and microscopic fractography performed on fracture specimens from low cycle fatigue (LCF) testings through an Alloy 617 base metal and weldments. The weldment specimens were taken from gas tungsten arc welding (GTAW) pad of Alloy 617. The aim of the present study is to investigate the macro- and microscopic aspects of the low cycle fatigue fracture mode and mechanism of Alloy 617 base metal and GTAWed weldment specimens. Fully axial total strain controlled fatigue tests were conducted at room temperature with total strain ranges of 0.6, 0.9, 1.2 and 1.5%. Macroscopic fracture surfaces of Alloy 617 base metal specimens showed a flat type normal to the fatigue loading direction, whereas the GTAWed weldment specimens were of a shear/star type. The fracture surfaces of both the base metal and weldment specimens revealed obvious fatigue striations at the crack propagation regime. In addition, the fatigue crack mechanism of the base metal showed a transgranular normal to fatigue loading direction; however, the GTAWed weldment specimens showed a transgranular at approximately 45° to the fatigue loading direction.

Condition For Strain-Hardening In Ecc Uniaxial Test Specimen

DEFF Research Database (Denmark)

Dick-Nielsen, Lars; Stang, Henrik; Poulsen, Peter Noe

2006-01-01

and infinite sheets under uniaxial tension. The crack is assumed to be cohesive and the cohesive law applied takes into account fiber as well as mortar properties. It is shown that the maximum crack opening observed during crack propagation in various test specimen geometries is small, 20 m and also small......This paper discusses the adequateness of the steady state flat crack criterion for crack propagation in Engineered Cementitious Composites. The investigation is performed by use of a semi-analytical model as well as a Finite Element Model. The simulations are for one crack propagating in finite...

Contact area measurements on structured surfaces

DEFF Research Database (Denmark)

Kücükyildiz, Ömer Can; Jensen, Sebastian Hoppe Nesgaard; De Chiffre, Leonardo

In connection with the use of brass specimens featuring structured surfaces in a tribology test, an algorithm was developed for automatic measurement of the contact area by optical means.......In connection with the use of brass specimens featuring structured surfaces in a tribology test, an algorithm was developed for automatic measurement of the contact area by optical means....

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

Comparison of Three Different Methods for Pile Integrity Testing on a Cylindrical Homogeneous Polyamide Specimen

Science.gov (United States)

Lugovtsova, Y. D.; Soldatov, A. I.

2016-01-01

Three different methods for pile integrity testing are proposed to compare on a cylindrical homogeneous polyamide specimen. The methods are low strain pile integrity testing, multichannel pile integrity testing and testing with a shaker system. Since the low strain pile integrity testing is well-established and standardized method, the results from it are used as a reference for other two methods.

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

Method for thinning specimen

Science.gov (United States)

Follstaedt, David M.; Moran, Michael P.

2005-03-15

A method for thinning (such as in grinding and polishing) a material surface using an instrument means for moving an article with a discontinuous surface with an abrasive material dispersed between the material surface and the discontinuous surface where the discontinuous surface of the moving article provides an efficient means for maintaining contact of the abrasive with the material surface. When used to dimple specimens for microscopy analysis, a wheel with a surface that has been modified to produce a uniform or random discontinuous surface significantly improves the speed of the dimpling process without loss of quality of finish.

Reverse-Transcriptase PCR Detection of Leptospira: Absence of Agreement with Single-Specimen Microscopic Agglutination Testing.

Science.gov (United States)

Waggoner, Jesse J; Balassiano, Ilana; Mohamed-Hadley, Alisha; Vital-Brazil, Juliana Magalhães; Sahoo, Malaya K; Pinsky, Benjamin A

2015-01-01

Reference diagnostic tests for leptospirosis include nucleic acid amplification tests, bacterial culture, and microscopic agglutination testing (MAT) of acute and convalescent serum. However, clinical laboratories often do not receive paired specimens. In the current study, we tested serum samples using a highly sensitive real-time nucleic acid amplification test for Leptospira and compared results to MAT performed on the same specimens. 478 serum samples from suspected leptospirosis cases in Rio de Janeiro were tested using a real-time RT-PCR for the diagnosis of leptospirosis, malaria and dengue (the Lepto-MD assay). The Lepto-MD assay detects all species of Leptospira (saprophytic, intermediate, and pathogenic), and in the current study, we demonstrate that this assay amplifies both Leptospira RNA and DNA. Dengue virus RNA was identified in 10 patients, and no cases of malaria were detected. A total of 65 samples (13.6%) were positive for Leptospira: 35 samples (7.3%) in the Lepto-MD assay, 33 samples (6.9%) by MAT, and 3 samples tested positive by both (kappa statistic 0.02). Poor agreement between methods was consistent regardless of the titer used to define positive MAT results or the day of disease at sample collection. Leptospira nucleic acids were detected in the Lepto-MD assay as late as day 22, and cycle threshold values did not differ based on the day of disease. When Lepto-MD assay results were added to the MAT results for all patients in 2008 (n=818), the number of detected leptospirosis cases increased by 30.4%, from 102 (12.5%) to 133 (16.3%). This study demonstrates a lack of agreement between nucleic acid detection of Leptospira and single-specimen MAT, which may result from the clearance of bacteremia coinciding with the appearance of agglutinating antibodies. A combined testing strategy for acute leptospirosis, including molecular and serologic testing, appears necessary to maximize case detection.

Relationships between Loblolly Pine small clear specimens and Dimension Lumber Tested in Static Bending

Science.gov (United States)

Mark Alexander Butler; Joseph Dahlen; Finto Antony; Michael Kane; Thomas L. Eberhardt; Huizhe Jin; Kim Love-Myers; John Paul McTague

2016-01-01

Prior to the 1980s, the allowable stresses for lumber in North America were derived from testing of small clear specimens. However, the procedures were changed because these models were found to be inaccurate. Nevertheless, small clear testing continues to be used around the world for allowable stress determinations and in studies that examine forest management impacts...

Method for independent strain and temperature measurement in polymeric tensile test specimen using embedded FBG sensors

DEFF Research Database (Denmark)

Pereira, Gilmar Ferreira; McGugan, Malcolm; Mikkelsen, Lars Pilgaard

2016-01-01

to calculate independently the strain and temperature are presented in the article, together with a measurement resolution study. This multi-parameter measurement method was applied to an epoxy tensile specimen, tested in a unidirectional tensile test machine with a temperature controlled cabinet. A full......A novel method to obtain independent strain and temperature measurements using embedded Fibre Bragg Grating (FBG) in polymeric tensile test specimens is presented in this paper. The FBG strain and temperature cross-sensitivity was decoupled using two single mode FBG sensors, which were embedded...... of temperature, from 40 C to -10 C. The consistency of the expected theoretical results with the calibration procedure and the experimental validation shows that this proposed method is applicable to measure accurate strain and temperature in polymers during static or fatigue tensile testing. Two different...

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)

Effect of surface treatments on stress corrosion cracking susceptibility of nickel base alloys

International Nuclear Information System (INIS)

Iwanami, Masaru; Kaneda, Junya; Tamako, Hiroaki; Hato, Hisamitsu; Takamoto, Shinichi

2009-01-01

Effect of surface treatment on SCC susceptibility of Ni base alloys was investigated. Cracks were observed in all grinding specimens in a creviced bent beam (CBB) test. On the other hand, no cracks occurred in shot peening (SP), water jet peening (WJP) specimens. It was indicated that these surface treatments effectively reduced the SCC susceptibility of nickel-base alloys. As a result of a residual stress test, the surface of specimens with grinding had high tensile residual stress. However, SP and WJP improved surface residual stress to compressive stress. The depth of the compressive effect of WJP was almost the same as that of SP. However, the surface hardness of WJP specimens differed from that of SP and it was found that WJP had less impact on surface hardening. This difference was consistent with their surface microstructures. The surface of SP specimens had clearly the deformation region, but the surface of WJP specimens was localized. (author)

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

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.

Technique for the residual life assessment of high temperature components based on creep-rupture testing on welded miniature specimens

Energy Technology Data Exchange (ETDEWEB)

Garzillo, A.; Guardamagna, C.; Moscotti, L.; Ranzani, L. [Ente Nazionale per l`Energia Elettrica, Milan (Italy)

1995-06-01

Following the present trend in the development of advanced methodologies for residual life assessment of high temperature components operating in power plants, particularly in non destructive methods, a testing technique has been set up at ENEL-CRAM based on creep-rupture testa in an argon on welded miniature specimens. Five experimental systems for creep-rupture tests in an argon atmosphere have been set up which include high accuracy systems, vacuum chambers and exrwnsometer devices. With the aim of establishing and validating the suitability of the experimental methodology, creep-rupture and interrupted creep testing programmes have been performed on miniature specimens (2 mm diameter and 10 mm gauge lenght). On the basis of experience gathered by various European research laboratories, a miniature specimen construction procedure has been developed using a laser welding technique for joining threaded heads to sample material. Low alloy ferritic steels, such as virgin 2.25CrlMo, 0.5Cr 0.5Mo 0.25V, and IN 738 superalloy miniature specimens have been investigated and the results, compared with those from standard specimens, show a regular trend in deformation vs time. Additional efforts to provide guidelines for material sampling from each plant component will be required in order to reduce uncertainties in residual life prediction.

Relationship between surface area for adhesion and tensile bond strength--evaluation of a micro-tensile bond test.

Science.gov (United States)

Sano, H; Shono, T; Sonoda, H; Takatsu, T; Ciucchi, B; Carvalho, R; Pashley, D H

1994-07-01

The purpose of this study was to test the null hypothesis that there is no relationship between the bonded surface area of dentin and the tensile strength of adhesive materials. The enamel was removed from the occlusal surface of extracted human third molars, and the entire flat surface was covered with resin composite bonded to the dentin to form a flat resin composite crown. Twenty-four hours later, the bonded specimens were sectioned parallel to the long axis of the tooth into 10-20 thin sections whose upper part was composed of resin composite with the lower half being dentin. These small sections were trimmed using a high speed diamond bur into an hourglass shape with the narrowest portion at the bonded interface. Surface area was varied by altering the specimen thickness and width. Tensile bond strength was measured using custom-made grips in a universal testing machine. Tensile bond strength was inversely related to bonded surface area. At surface areas below 0.4 mm2, the tensile bond strengths were about 55 MPa for Clearfil Liner Bond 2 (Kuraray Co., Ltd.), 38 MPa for Scotchbond MP (3M Dental Products), and 20 MPa for Vitremer (3M Dental Products). At these small surface areas all of the bond failures were adhesive in nature. This new method permits measurement of high bond strengths without cohesive failure of dentin. It also permits multiple measurements to be made within a single tooth.

ASTM international symposium on small specimen test techniques and their applications to pressure vessel annealing and plant life extension

International Nuclear Information System (INIS)

Garner, F.A.; Hamilton, M.L.; Heinisch, H.L.; Kumar, A.S.

1992-01-01

Miniature sheet-type tensile specimens are currently being used in a variety of radiation damage studies conducted in a number of different reactors. Although these specimens are very small, they have proven successful in addressing issues encountered in both thermal reactors and anticipated fusion reactors. This paper reviews the results of a number of recent studies that illustrate the range of applicability of these small specimens. When combined with other types of specimens and other types of measurements made prior to tensile testing, miniature tensile specimens have been found to serve as very useful tools for application to both fundamental studies and alloy screening studies

Assessment of the stability of DNA in specimens collected under conditions for drug testing-A pilot study.

Science.gov (United States)

White, Robert M; Mitchell, John M; Hart, E Dale; Evans, Amy; Meaders, Meredith; Norsworthy, Sarah E; Hayes, Eugene D; Flegel, Ron; Maha, George C; Shaffer, Megan D; Hall, Erin M; Rogers, Kelley

2018-02-01

For forensic biological sample collections, the specimen donor is linked solidly to his or her specimen through a chain of custody (CoC) sometimes referenced as a chain of evidence. Rarely, a donor may deny that a urine or oral fluid (OF) specimen is his or her specimen even with a patent CoC. The goal of this pilot study was to determine the potential effects of short-term storage on the quality and quantity of DNA in both types of specimen under conditions that may be encountered with employment-related drug testing specimens. Fresh urine and freshly collected oral fluid all produced complete STR profiles. For the "pad" type OF collectors, acceptable DNA was extractable both from the buffer/preservative and the pad. Although fresh urine and OF produced complete STR profiles, partial profiles were obtained after storage for most samples. An exception was the DNA in the Quantisal OF collector, from which a complete profile was obtained for both freshly collected OF and stored OF. Copyright © 2017 Elsevier B.V. All rights reserved.

Basic research into eddy current testing of austenetic weld joints and surface claddings

International Nuclear Information System (INIS)

Meier, W.

1976-01-01

The result of research work has shown that the eddy-current testing method can be used for austenetic steel up to 10 mm thick to detect cracks in the material. An exception to this are laminations if they are parallel to the surface. Cracks in the various geometrical positions in the test specimen produce different results in the x-y plot. They are influenced by the direction of the material cracks. Research into the influence the geometric parameters have on the indications shows that the eddy-current method provides clearer interpretations of material cracks than any other non-destructive test method known. (orig.) [de

Special fracture mechanics specimens for multilayer plastic pipes testing

Czech Academy of Sciences Publication Activity Database

Hutař, Pavel; Šestáková, Lucie; Knésl, Zdeněk; Nezbedová, E.; Náhlík, Luboš

2009-01-01

Roč. 28, č. 8 (2009), s. 785-792 ISSN 0142-9418 R&D Projects: GA ČR GA106/09/0279; GA ČR GC101/09/J027 Institutional research plan: CEZ:AV0Z20410507 Keywords : Multilayer plastic pipes * C-type specimen * K-calibration * Fracture toughness * Slow crack growth * Non-homogenous specimens Subject RIV: JL - Material s Fatigue, Friction Mechanics Impact factor: 1.667, year: 2009

Design, Fabrication and Test Report on a Verification Capsule (05M-06K) for the Control of a Neutron Irradiation Fluence of Specimens in HANARO

Energy Technology Data Exchange (ETDEWEB)

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

2007-02-15

As a part of a project for a capsule development and utilization for an irradiation test, a verification capsule (05M-06K) was designed, fabricated and tested for the development of new instrumented capsule technology for a more precise control of the irradiation fluence of a specimen, irrespective of the reactor operation condition. The basic structure of the 05M-06K capsule was based on the 04M-22K mock-up capsule which was successfully designed and out-pile tested to confirm the various key technologies necessary for the fluence control of a specimen. 21 square and round shaped specimens made of STS 304 were inserted into the capsule. The capsule was constructed in 5 stages with specimens and an independent electric heater at each stage. Each of the five specimens which were accommodated in the 1st stage (top) of the capsule can be taken out of the HANARO core during a normal reactor operation. The specimen is extracted by a specimen extraction mechanism using a steel wire. During the out-pile test, the temperatures of the specimens were measured by 12 thermocouples installed in the capsule. The capsule was successfully out-pile tested in a single channel test loop. The obtained results will be used for a safety evaluation of the new irradiation capsule for controlling the irradiation fluence of specimens in HANARO.

Computer-aided, single-specimen controlled bending test for fracture-kinetics measurement in ceramics

International Nuclear Information System (INIS)

Borovik, V.G.; Chushko, V.M.; Kovalev, S.P.

1995-01-01

Fracture testing of ceramics by using controlled crack growth is proposed to allow study of crack-kinetics behavior under a given loading history. A computer-aided, real-time data acquisition system improves the quality of crack-growth parameters obtained in a simple, single-specimen bend test. Several ceramic materials were tested in the present study: aluminum nitride as a linear-elastic material; and alumina and yttria-stabilized zirconia, both representative of ceramics with microstructure-dependent nonlinear fracture properties. Ambiguities in the crack-growth diagrams are discussed to show the importance of accounting for crack-growth history in correctly describing nonequilibrium fracture behavior

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

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.

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...

Effect of various tooth whitening modalities on microhardness, surface roughness and surface morphology of the enamel.

Science.gov (United States)

Kwon, So Ran; Kurti, Steven R; Oyoyo, Udochukwu; Li, Yiming

2015-09-01

The purpose of this study was to evaluate the effect of four whitening modalities on surface enamel as assessed with microhardness tester, profilometer, and scanning electron microscopy (SEM). Whitening was performed according to manufacturer's directions for over-the-counter (OTC), dentist dispensed for home use (HW) and in-office (OW) whitening. Do-it-yourself (DIY) whitening consisted of a strawberry and baking soda mix. Additionally, negative and positive controls were used. A total of 120 enamel specimens were used for microhardness testing at baseline and post-whitening. Following microhardness testing specimens were prepared for SEM observations. A total of 120 enamel specimens were used for surface roughness testing at baseline and post-whitening (n = 20 per group). Rank-based Analysis of Covariance was performed to compare microhardness and surface roughness changes. Tests of hypotheses were two-sided with α = 0.05. There was a significant difference in Knoop hardness changes (ΔKHN) among the groups (Kruskal-Wallis test, p whitening modalities-DIY, OTC, HW and OW induced minimal surface morphology changes when observed with SEM. It can be concluded that none of the four whitening modalities adversely affected enamel surface morphology. However, caution should be advised when using a DIY regimen as it may affect enamel microhardness and an OTC product as it has the potential to increase surface roughness.

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)

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)

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.

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.)

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.)

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.

Crack propagation under thermal cycling loading inducing a thermal gradient in the specimen thickness

International Nuclear Information System (INIS)

Le, H.N.

2009-05-01

This study aims to figure out the crack growth phenomenon by thermal fatigue induced by thermal gradient through thickness of specimen. Firstly, an experimental facility has been developed: a rectangular parallelepiped specimen is subjected to thermal cycling between 350 C and 100 C; the specimen is freed to expand and contract. Two semi-circular notches (0,1 mm depth and 4 mm length) have been machined on the surface of the specimen. A series of interrupted tests has been carried out to characterize and quantify the crack growth in depth and surface of the pre-existing crack. Next, a three-dimensional crack growth simulation has been implemented in ABAQUS. Automation using Python was used to simulate the propagation of a crack under thermal cycling, with re-meshing at crack front after each calculation step. No assumption has been taken on the crack front during the crack propagation. A comparison with test results showed very good agreement on the evolution of crack front shape and on the kinetics of propagation on the edge and the heart of pre-existing crack. An analytical approach was also developed based on the calculation of stress intensity factors (SIC). A two-dimensional approach was first introduced enabling us to better understand the influence of various thermal and geometric parameters. Finally, a three dimensional approach, with an elliptical assumption crack shape during the propagation, leading to a prediction of crack growth on the surface and in depth which is very similar to that obtained numerically, but with computational time much lower. (author)

Direct Observation of Asperity Deformation of Specimen with Random Rough Surface in Upsetting Process

DEFF Research Database (Denmark)

Azushima, A.; Kuba, S.; Tani, S.

2004-01-01

The trapping behavior of liquid lubricant and contact behavior of asperities at the workpiece-tool interface during upsetting and indentation are observed directly using a compression subpress which consists of a transparent die made of sapphire, a microscope with a CCD camera and a video system....... The experiments are carried out without lubricant and with lubricant. Specimens used are commercially pure A1100 Aluminum with a random rough surface. From this observation, the change in the fraction of real contact area is measured by an image processor. The real contact area ratios in upsetting experiment...

Yield surface investigation of alloys during model disk spin tests

Directory of Open Access Journals (Sweden)

E. P. Kuzmin

2014-01-01

Full Text Available Gas-turbine engines operate under heavy subsequently static loading conditions. Disks of gas-turbine engine are high loaded parts of irregular shape having intensive stress concentrators wherein a 3D stress strain state occurs. The loss of load-carrying capability or burst of disk can lead to severe accident or disaster. Therefore, development of methods to assess deformations and to predict burst is one of the most important problems.Strength assessment approaches are used at all levels of engine creation. In recent years due to actively developing numerical method, particularly FEA, it became possible to investigate load-carrying capability of irregular shape disks, to use 3D computing schemes including flow theory and different options of force and deformation failure criteria. In spite of a wide progress and practical use of strength assessment approaches, there is a lack of detailed research data on yield surface of disk alloys. The main purpose of this work is to validate the use of basis hypothesis of flow theory and investigate the yield surface of disk alloys during the disks spin test.The results of quasi-static numerical simulation of spin tests of model disk made from high-temperature forged alloy are presented. To determine stress-strain state of disk during loading finite element analysis is used. Simulation of elastic-plastic strain fields was carried out using incremental theory of plasticity with isotropic hardening. Hardening function was taken from the results of specimens tensile test. Specimens were cut from a sinkhead of model disk. The paper investigates the model sensitivity affected by V.Mises and Tresca yield criteria as well as the Hosford model. To identify the material model parameters the eddy current sensors were used in the experimental approach to measure rim radial displacements during the load-unload of spin test. The results of calculation made using different material models were compared with the

Service-cycle component-feature specimen TMF testing of steam turbine rotor steels

Energy Technology Data Exchange (ETDEWEB)

Radosavljevic, M.; Holdsworth, S.R. [Eidgenoessische Materialpruefungs- und Forschungsanstalt, Duebendorf (Switzerland); Mazza, E. [Eidgenoessische Materialpruefungs- und Forschungsanstalt, Duebendorf (Switzerland); Eidgenoessische Technische Hochschule (ETH), Zurich (Switzerland); Grossmann, P.; Ripamonti, L. [ALSTOM Power (Switzerland) Ltd., Baden (Switzerland)

2010-07-01

This paper reviews the methodology adopted in a Swiss Research Collaboration to devise a component-feature representative specimen geometry and the TMF cycle parameters necessary to closely simulate arduous steam turbine operating duty. Implementation of these service-like experimental conditions provides a practical indication of the effectiveness of deformation and crack initiation endurance predictions. Comprehensive post test inspection provides evidence to demonstrate the physical realism of the laboratory simulations in terms of the creep-fatigue damage generated during the benchmark tests. Mechanical response results and physical damage observations are presented and their practical implications discussed for the example of a 2%CrMoNiWV rotor service cycle. (orig.)

Linear Array Ultrasonic Testing Of A Thick Concrete Specimens For Non-Destructive Evaluation

Energy Technology Data Exchange (ETDEWEB)

Clayton, Dwight A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Khazanovich, Lev [Univ. of Minnesota, Minneapolis, MN (United States); Zammerachi, Mattia [Univ. of Minnesota, Minneapolis, MN (United States); Ezell, N. Dianne Bull [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-04-01

The University of Minnesota and Oak Ridge National Laboratory are collaborating on the design and construction of a concrete specimen with sufficient reinforcement density and cross-sectional size to represent a light water reactor (LWR) containment wall with various defects. The preliminary analysis of the collected data using extended synthetic aperture focussin technique (SAFT) reconstruction indicated a great potential of the ultrasound array technology for locating relatively shallow distresses. However, the resolution and reliability of the analysis is inversely proportional to the defect depth and the amount of reinforcement between the measurement point and the defect location. The objective of this round of testing is to evaluate repeatability of the obtained reconstructions from measurements with different frequencies as well as to examine the effect of the duration of the sending ultrasound signal on the resulting reconstructions. Two series of testing are performed in this study. The objective of the first series is to evaluate repeatability of the measurements and resulting reconstructed images. The measurements use three center frequencies. Five measurements are performed at each location with and without lifting the device. The analysis of the collected data suggested that a linear array ultrasound system can produce reliably repeatable reconstructions using 50 kHz signals for relatively shallow depths (less than 0.5 m). However, for reconstructions at the greater depths the use of lower frequency and/or signal filtering to reduce the effect of signal noise may be required. The objective of the second series of testing is to obtain measurements with various impulse signal durations. The entire grid on the smooth surface is tested with four different various impulse signal durations. An analysis of the resulting extended SAFT reconstructions suggested that Kirchhoff-based migration leads to easier interpreting reconstructions when shorter duration

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.

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

Development of small specimen test techniques. Development of a remote controlled small punch testing apparatus

International Nuclear Information System (INIS)

Ohmi, Masao; Saito, Junichi; Ooka, Norikazu; Jitsukawa, Shiro; Hishinuma, Akimichi; Umino, Akira.

1997-01-01

An accelerator-driven deuterium-lithium (d-Li) stripping reaction-type neutron source, such as the International Fusion Materials Irradiation Facility (IFMIF) planned by the International Energy Agency is recognized as one of the most promising facility to obtain test environments of high-energy neutrons for fusion reactor materials development. The limitation on the available irradiation volume of the irradiation facility requires the development of the small specimen test techniques (SSTT). Application of SSTT to evaluate the degradation of various components in the light water reactor for the life extension is expected to be also quite beneficial. A remote-controlled testing machine for the Small Punch (SP) and miniaturized tensile tests was developed at the hot laboratory of the Japan Materials Testing Reactor (JMTR). The machine is designed for testing at temperatures ranging between 93 and 1,123 K to evaluate the temperature dependence of the strength of materials including the embrittlement at low temperatures and the softening at elevated temperatures. The tests are performed in a vacuum or in an inert gas environment. The machine has been installed in a hot cell and is being used for the round robin test program of the SP test method. The round robin test program is planned to identify the capability of the test method and to establish a standard test procedure. The configuration and the specifications of the test machine are introduced and the results of the SP tests are also shown. (author)

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.

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

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)

Gamma irradiation test report of simulated grout specimens for gas generation/liquid advection

International Nuclear Information System (INIS)

Hinman, C.A.

1994-01-01

This report presents the results from an irradiation test performed on four specimens of grout that were fabricated from synthetic Double Shell Slurry Feed (DSSF) liquid waste. The objective was to investigate the radiolytic generation of gases and the potential for advective rejection of waste liquids from the grout matrix and to provide experimental information for the validation of the C-Cubed calculated model. It has been demonstrated that a number of gases can be formed within the grout due to radiolytic decomposition of various chemical components that make up the grout. This observation leads to the conjecture that the potential exists for the rejection of a portion of the 60 vol% free liquid from the grout matrix driven by pressurization by these gases. It was found that, for the specimen geometries used in this test series, and for peak radiation dose accumulation rates on the order of 4 to 60 times of the initial rate expected in the grout vaults (300 Rads/hr), no liquid rejection was observed from 2% to 35% of the target exposure expected in the grout vaults (1E+08 Rads). When the irradiation rate exceeded the projected grout vault dose rate by a factor of 200 a small amount of liquid rejection was observed from one of two specimens that had received 20% more than the goal exposure. Because of the differences in the magnitudes of the relative radiation field strengths between this study and an actual grout vault, it is concluded that the potential for liquid rejection by internal gas pressurization from presently configured grout waste forms is very low for the expected conditions

Evaluation and comparison of multiple test methods, including real-time PCR, for Legionella detection in clinical specimens.

Directory of Open Access Journals (Sweden)

Adriana Peci

2016-08-01

Full Text Available Legionella is a gram-negative bacterium that can cause Pontiac fever, a mild upper respiratory infection and Legionnaire’s disease, a more severe illness. We aimed to compare the performance of urine antigen, culture and PCR test methods and to determine if sputum is an alternative to the use of more invasive bronchoalveolar lavage (BAL. Data for this study included specimens tested for Legionella at PHOL from January 1, 2010 to April 30, 2014, as part of routine clinical testing. We found sensitivity of UAT compared to culture to be 87%, specificity 94.7%, positive predictive value (PPV 63.8% and negative predictive value (NPV 98.5%. Sensitivity of UAT compared to PCR was 74.7%, specificity 98.3%, PPV 77.7% and NPV 98.1%. Of 146 patients who had a Legionella positive result by PCR, only 66(45.2% also had a positive result by culture. Sensitivity for culture was the same using either sputum or BAL (13.6%; sensitivity for PCR was 10.3% for sputum and 12.8% for BAL. Both sputum and BAL yield similar results despite testing methods (Fisher Exact p-values=1.0, for each test. In summary, all test methods have inherent weaknesses in identifying Legionella; thereforemore than one testing method should be used. Obtaining a single specimen type from patients with pneumonia limits the ability to diagnose Legionella, particularly when urine is the specimen type submitted. Given ease of collection, and similar sensitivity to BAL, clinicians are encouraged to submit sputum in addition to urine when BAL submission is not practical, from patients being tested for Legionella.

Standard practice for preparing, cleaning, and evaluating corrosion test specimens

CERN Document Server

American Society for Testing and Materials. Philadelphia

2003-01-01

1.1 This practice covers suggested procedures for preparing bare, solid metal specimens for tests, for removing corrosion products after the test has been completed, and for evaluating the corrosion damage that has occurred. Emphasis is placed on procedures related to the evaluation of corrosion by mass loss and pitting measurements. (Warning—In many cases the corrosion product on the reactive metals titanium and zirconium is a hard and tightly bonded oxide that defies removal by chemical or ordinary mechanical means. In many such cases, corrosion rates are established by mass gain rather than mass loss.) 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see 1 and 7.2.

Surface and near surface defect detection in thick copper EB-welds using eddy current testing

International Nuclear Information System (INIS)

Pitkaenen, J.; Lipponen, A.

2010-01-01

The surface inspection of thick copper electron beam (EB) welds plays an important role in the acceptance of nuclear fuel disposal. The main reasons to inspect these components are related to potential manufacturing and handling defects. In this work the data acquisition software, visualising tools for eddy current (EC) measurements and eddy current sensors were developed for detection of unwanted defects. The eddy current equipment was manufactured by IZFP and the visualising software in active co-operation with Posiva and IZFP for the inspections. The inspection procedure was produced during the development of the inspection techniques. The inspection method development aims to qualify the method for surface and near surface defect detection and sizing according to ENIQ. The study includes technical justification to be carried out, and compilation of a defect catalogue and experience from measurements within the Posiva's research on issues related to manufacturing. The depth of penetration in copper components in eddy current testing is rather small. To detect surface breaking defects the eddy current inspection is a good solution. A simple approach was adopted using two techniques: higher frequency was used to detect surface defects and to determine the dimensions of the defects except depth, lower frequency was used to detect defects having a ligament and for sizing of deeper surface breaking defects. The higher frequency was 30 kHz and the lower frequency was 200 Hz. The higher frequency probes were absolute bobbing coils and lower frequency probes combined transmitter - several receiver coils. To evaluate both methods, calibration blocks were manufactured by FNS for weld inspections. These calibration specimens mainly consisted of electron discharge machined notches and holes of varying shapes, lengths and diameters in the range of 1 mm to 20 mm of depth. Also one copper lid specimen with 152 defects was manufactured and used for evaluation of weld inspection

Intergranular corrosion testing of austenitic stainless steels in nitric acid solutions

Energy Technology Data Exchange (ETDEWEB)

Whillock, G.O.H.; Dunnett, B. F. [British Nuclear Fuels plc, BNFL, B170, Sellafield, Seascale, Cumbria CA20 1PG (United Kingdom)

2004-07-01

In hot strong nitric acid solutions, stainless steels exhibit intergranular corrosion. Corrosion rates are often measured from immersion testing of specimens manufactured from the relevant material (e.g. plate or pipe). The corrosion rates, measured from weight loss, are found to increase with time prior to reaching steady state, which can take thousands of hours to achieve. The apparent increase in corrosion rate as a function of time was found to be an artefact due to the surface area of the specimen's being used in the corrosion rate calculations, rather than that of the true area undergoing active corrosion i.e. the grain boundaries. The steady state corrosion rate coincided with the onset of stable grain dropping, where the use of the surface area of the specimen to convert the weight loss measurements to corrosion rates was found to be appropriate. This was confirmed by sectioning of the specimens and measuring the penetration depths. The rate of penetration was found to be independent of time and no induction period was observed. A method was developed to shorten considerably the testing time to reach the steady state corrosion rate by use of a pre-treatment that induces grain dropping. The long-term corrosion rates from specimens which were pre-treated was similar to that achieved after prolonged testing of untreated (i.e. initially ground) specimens. The presence of cut surfaces is generally unavoidable in the simple immersion testing of specimens in test solutions. However, inaccuracy in the results may occur as the measured corrosion rate is often influenced by the orientation of the microstructure, the highest rates typically being observed on the cut surfaces. Two methods are presented which allow deconvolution of the corrosion rates from immersion testing of specimens containing cut surfaces, thus allowing reliable prediction of the long-term corrosion rate of plate surfaces. (authors)

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

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

Mesh-morphing algorithms for specimen-specific finite element modeling.

Science.gov (United States)

Sigal, Ian A; Hardisty, Michael R; Whyne, Cari M

2008-01-01

Despite recent advances in software for meshing specimen-specific geometries, considerable effort is still often required to produce and analyze specimen-specific models suitable for biomechanical analysis through finite element modeling. We hypothesize that it is possible to obtain accurate models by adapting a pre-existing geometry to represent a target specimen using morphing techniques. Here we present two algorithms for morphing, automated wrapping (AW) and manual landmarks (ML), and demonstrate their use to prepare specimen-specific models of caudal rat vertebrae. We evaluate the algorithms by measuring the distance between target and morphed geometries and by comparing response to axial loading simulated with finite element (FE) methods. First a traditional reconstruction process based on microCT was used to obtain two natural specimen-specific FE models. Next, the two morphing algorithms were used to compute mappings from the surface of one model, the source, to the other, the target, and to use this mapping to morph the source mesh to produce a target mesh. The microCT images were then used to assign element-specific material properties. In AW the mappings were obtained by wrapping the source and target surfaces with an auxiliary triangulated surface. In ML, landmarks were manually placed on corresponding locations on the surfaces of both source and target. Both morphing algorithms were successful in reproducing the shape of the target vertebra with a median distance between natural and morphed models of 18.8 and 32.2 microm, respectively, for AW and ML. Whereas AW-morphing produced a surface more closely resembling that of the target, ML guaranteed correspondence of the landmark locations between source and target. Morphing preserved the quality of the mesh producing models suitable for FE simulation. Moreover, there were only minor differences between natural and morphed models in predictions of deformation, strain and stress. We therefore conclude that

High resolution SAW elastography for ex-vivo porcine skin specimen

Science.gov (United States)

Zhou, Kanheng; Feng, Kairui; Wang, Mingkai; Jamera, Tanatswa; Li, Chunhui; Huang, Zhihong

2018-02-01

Surface acoustic wave (SAW) elastography has been proven to be a non-invasive, non-destructive method for accurately characterizing tissue elastic properties. Current SAW elastography technique tracks generated surface acoustic wave impulse point by point which are a few millimeters away. Thus, reconstructed elastography has low lateral resolution. To improve the lateral resolution of current SAW elastography, a new method was proposed in this research. A M-B scan mode, high spatial resolution phase sensitive optical coherence tomography (PhS-OCT) system was employed to track the ultrasonically induced SAW impulse. Ex-vivo porcine skin specimen was tested using this proposed method. A 2D fast Fourier transform based algorithm was applied to process the acquired data for estimating the surface acoustic wave dispersion curve and its corresponding penetration depth. Then, the ex-vivo porcine skin elastogram was established by relating the surface acoustic wave dispersion curve and its corresponding penetration depth. The result from the proposed method shows higher lateral resolution than that from current SAW elastography technique, and the approximated skin elastogram could also distinguish the different layers in the skin specimen, i.e. epidermis, dermis and fat layer. This proposed SAW elastography technique may have a large potential to be widely applied in clinical use for skin disease diagnosis and treatment monitoring.

46 CFR 57.04-1 - Test specimen requirements and definition of ranges (modifies QW 202, QW 210, QW 451, and QB 202).

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Test specimen requirements and definition of ranges... HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING WELDING AND BRAZING Procedure Qualification Range § 57.04-1 Test specimen requirements and definition of ranges (modifies QW 202, QW 210, QW 451, and QB 202...

USFDA-GUIDELINE BASED VALIDATION OF TESTING METHOD FOR RIFAMPICIN IN INDONESIAN SERUM SPECIMEN

Directory of Open Access Journals (Sweden)

Tri Joko Raharjo

2010-06-01

Full Text Available Regarding a new regulation from Indonesia FDA (Badan POM-RI, all new non patent drugs should show bioequivalence with the originator drug prior to registration. Bioequivalence testing (BE-testing has to be performed to the people that represented of population to which the drug to be administrated. BE testing need a valid bio-analytical method for certain drug target and group of population. This research report specific validation of bio-analysis of Rifampicin in Indonesian serum specimen in order to be used for BE testing. The extraction was performed using acetonitrile while the chromatographic separation was accomplished on a RP 18 column (250 × 4.6 mm i.d., 5 µm, with a mobile phase composed of KH2PO4 10 mM-Acetonitrile (40:60, v/v and UV detection was set at 333 nm. The method shown specificity compared to blank serum specimen with retention time of rifampicin at 2.1 min. Lower limit of quantification (LLOQ was 0.06 µg/mL with dynamic range up to 20 µg/mL (R>0.990. Precision of the method was very good with coefficient of variance (CV 0.58; 7.40 and 5.56% for concentration at 0.06, 5, 15 µg/mL, respectively. Accuracies of the method were 3.22; 1.94; 1.90% for concentration 0.06, 5 and 15 µg/mL respectively. The average recoveries were 97.82, 95.50 and 97.31% for concentration of rifampicin 1, 5 and 5 µg/mL, respectively. The method was also shown reliable result on stability test on freezing-thawing, short-term and long-term stability as well as post preparation stability. Validation result shown that the method was ready to be used for Rifampicin BE testing with Indonesian subject.   Keywords: Rifampicin, Validation, USFDA-Guideline

49 CFR 40.173 - Who is responsible for paying for the test of a split specimen?

Science.gov (United States)

2010-10-01

... is responsible for paying for the test of a split specimen? (a) As the employer, you are responsible... 49 Transportation 1 2010-10-01 2010-10-01 false Who is responsible for paying for the test of a.... (b) As the employer, you must not condition your compliance with these requirements on the employee's...

Evaluation and Comparison of Multiple Test Methods, Including Real-time PCR, for Legionella Detection in Clinical Specimens

Science.gov (United States)

Peci, Adriana; Winter, Anne-Luise; Gubbay, Jonathan B.

2016-01-01

Legionella is a Gram-negative bacterium that can cause Pontiac fever, a mild upper respiratory infection and Legionnaire’s disease, a more severe illness. We aimed to compare the performance of urine antigen, culture, and polymerase chain reaction (PCR) test methods and to determine if sputum is an acceptable alternative to the use of more invasive bronchoalveolar lavage (BAL). Data for this study included specimens tested for Legionella at Public Health Ontario Laboratories from 1st January, 2010 to 30th April, 2014, as part of routine clinical testing. We found sensitivity of urinary antigen test (UAT) compared to culture to be 87%, specificity 94.7%, positive predictive value (PPV) 63.8%, and negative predictive value (NPV) 98.5%. Sensitivity of UAT compared to PCR was 74.7%, specificity 98.3%, PPV 77.7%, and NPV 98.1%. Out of 146 patients who had a Legionella-positive result by PCR, only 66 (45.2%) also had a positive result by culture. Sensitivity for culture was the same using either sputum or BAL (13.6%); sensitivity for PCR was 10.3% for sputum and 12.8% for BAL. Both sputum and BAL yield similar results regardless testing methods (Fisher Exact p-values = 1.0, for each test). In summary, all test methods have inherent weaknesses in identifying Legionella; therefore, more than one testing method should be used. Obtaining a single specimen type from patients with pneumonia limits the ability to diagnose Legionella, particularly when urine is the specimen type submitted. Given ease of collection and similar sensitivity to BAL, clinicians are encouraged to submit sputum in addition to urine when BAL submission is not practical from patients being tested for Legionella. PMID:27630979

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.

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

Two-step method to evaluate equibiaxial residual stress of metal surface based on micro-indentation tests

International Nuclear Information System (INIS)

Nishikawa, Masaaki; Soyama, Hitoshi

2011-01-01

Highlights: → The sensitivity to residual stress was improved by selecting the depth parameter. → Residual stress could be obtained while determining the effect of unknown parameters. → The estimated residual stress agreed well with those of X-ray diffraction. -- Abstract: The present study proposed a method to evaluate the equibiaxial compressive residual stress of a metal surface by means of a depth-sensing indentation method using a spherical indenter. Inverse analysis using the elastic-plastic finite-element model for an indentation test was established to evaluate residual stress from the indentation load-depth curve. The proposed inverse analysis utilizes two indentation test results for a reference specimen whose residual stress is already known and for a target specimen whose residual stress is unknown, in order to exclude the effect of other unknown mechanical properties, such as Young's modulus and yield stress. Residual stress estimated by using the indentation method is almost identical to that measured by X-ray diffraction for indentation loads of 0.49-0.98 N. Therefore, it can be concluded that the proposed method can effectively evaluate residual stress on metal surface.

Surface properties and corrosion behavior of Co-Cr alloy fabricated with selective laser melting technique.

Science.gov (United States)

Xin, Xian-zhen; Chen, Jie; Xiang, Nan; Wei, Bin

2013-01-01

We sought to study the corrosion behavior and surface properties of a commercial cobalt-chromium (Co-Cr) alloy which was fabricated with selective laser melting (SLM) technique. For this purpose, specimens were fabricated using different techniques, such as SLM system and casting methods. Surface hardness testing, microstructure observation, surface analysis using X-ray photoelectron spectroscopy (XPS) and electrochemical corrosion test were carried out to evaluate the corrosion properties and surface properties of the specimens. We found that microstructure of SLM specimens was more homogeneous than that of cast specimens. The mean surface hardness values of SLM and cast specimens were 458.3 and 384.8, respectively; SLM specimens showed higher values than cast ones in hardness. Both specimens exhibited no differences in their electrochemical corrosion properties in the artificial saliva through potentiodynamic curves and EIS, and no significant difference via XPS. Therefore, we concluded that within the scope of this study, SLM-fabricated restorations revealed good surface properties, such as proper hardness, homogeneous microstructure, and also showed sufficient corrosion resistance which could meet the needs of dental clinics.

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

Strength Prediction and Failure Modes of Concrete Specimens Subjected to the Split Test

DEFF Research Database (Denmark)

Hoang, Linh Cao; Andersen, M.E.; Hansen, N.T.

2014-01-01

This paper deals with modelling and test of concrete specimens subjected to the Brazilian split test. Based on the fictitious crack concept, a simple model for the crack propagation process in the splitting plane is developed. From the model, it is possible to determine the distribution of residual...... tensile strength as crack propagation take place. The residual tensile strength is thereafter used in a rigid plastic analysis of the splitting failure. Based on this combined approach, the ultimate load may either be governed by crack propagation or by a plastic failure, which then terminates the crack...

SurePath Specimens Versus ThinPrep Specimen Types on the COBAS 4800 Platform: High-Risk HPV Status and Cytology Correlation in an Ethnically Diverse Bronx Population.

Science.gov (United States)

Naeem, R C; Goldstein, D Y; Einstein, Mark H; Ramos Rivera, G; Schlesinger, K; Khader, S N; Suhrland, M; Fox, A S

2017-08-01

To compare the cytologic preparations of 130 cervical specimens (from women of various ethnicities at high risk for human papillomavirus [HPV] infection) using the SurePath (SP) collection system with specimens gathered using the ThinPrep (TP) system, as processed on the Cobas 4800 analyzer, to determine which collection method more accurately identifies HPV infection. In our prospective study, specimens were collected from 130 women of various ethnicities residing in or near Bronx County, NY. The SP-collected specimen was first processed for cytologic findings; if clinical HPV testing was requested on that specimen, it was tested using Hybrid Capture II (HC2) methodology. We tested the remnant SP-collected cell concentrate using the Cobas analyzer. Then, the TP-collected and SP-collected specimens were tested in the same run on that analyzer, and the results were compared. We also compared the results with the concurrent cytologic findings. The results were concordant for overall HR-HPV status in 93.8% of cases. Also, a statistically significant lower cycle threshold value was observed with Cobas testing of specimen concentrates tested via the BD SurePath Pap Test (P = .001), suggesting higher sensitivity compared with specimens tested via the ThinPrep Pap Test. Cobas 4800 HPV testing of SP-collected specimen concentrates yields comparable results to TP-collected specimen concentrates. Based on the limited data that we derived, SP collection may be a more favorable methodology than TP collection for HPV testing of individuals at high risk in our ethnically diverse, urban patient population. © American Society for Clinical Pathology, 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

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

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

Accurate characterization of wafer bond toughness with the double cantilever specimen

Science.gov (United States)

Turner, Kevin T.; Spearing, S. Mark

2008-01-01

The displacement loaded double cantilever test, also referred to as the "Maszara test" and the "crack opening method" by the wafer bonding community, is a common technique used to evaluate the interface toughness or surface energy of direct wafer bonds. While the specimen is widely used, there has been a persistent question as to the accuracy of the method since the actual specimen geometry differs from the ideal beam geometry assumed in the expression used for data reduction. The effect of conducting the test on whole wafer pairs, in which the arms of cantilevers are wide plates rather than slender beams, is examined in this work using finite element analysis. A model is developed to predict the equilibrium shape of the crack front and to develop a corrected expression for calculating interface toughness from crack length measurements obtained in tests conducted on whole wafer pairs. The finite element model, which is validated through comparison to experiments, demonstrates that using the traditional beam theory-based expressions for data reduction can lead to errors of up to 25%.

Observation of fracture behavior of 3-D printed specimens under rolling contact fatigue in water

Directory of Open Access Journals (Sweden)

Mizobe Koshiro

2017-01-01

Full Text Available Polymer bearing was widely used in the corrosive conditions because of its high corrosion durability. The polymer bearing had been formed using molding and machining until the new 3-D printing method was developed. In this study, we performed the rolling contact fatigue tests of the 3-D printed specimens in water and observed the fracture behaviour of the specimens. We found that the surface cracks are related to both the rolling direction and the lamination directions.

Standard practice for verification of testing frame and specimen alignment under tensile and compressive axial force application

CERN Document Server

American Society for Testing and Materials. Philadelphia

2005-01-01

1.1 Included in this practice are methods covering the determination of the amount of bending that occurs during the application of tensile and compressive forces to notched and unnotched test specimens in the elastic range and to plastic strains less than 0.002. These methods are particularly applicable to the force application rates normally used for tension testing, creep testing, and uniaxial fatigue testing.

Standard practice for verification of testing frame and specimen alignment under tensile and compressive axial force application

CERN Document Server

American Society for Testing and Materials. Philadelphia

2014-01-01

1.1 Included in this practice are methods covering the determination of the amount of bending that occurs during the application of tensile and compressive forces to notched and unnotched test specimens in the elastic range and to plastic strains less than 0.002. These methods are particularly applicable to the force application rates normally used for tension testing, creep testing, and uniaxial fatigue testing.

High-Throughput Testing of Urogenital and Extragenital Specimens for Detection of Chlamydia Trachomatis and Neisseria Gonorrhoeae with Cobas® CT/NG.

Science.gov (United States)

Marlowe, Elizabeth M; Hardy, David; Krevolin, Mark; Gohl, Peter; Bertram, Alexander; Arcenas, Rodney; Seiverth, Britta; Schneider, Tanja; Liesenfeld, Oliver

2017-09-01

We compared the analytical and clinical performance of cobas ® CT/NG for use on the Cobas ® 6800/8800 Systems with the Cobas ® 4800 CT/NG Test from urogenital and extragenital specimens in over 12,000 specimens from both male and female subjects in Germany and the United States. The analytical sensitivity was ≤40 EB/ml for Chlamydia trachomatis (CT) and ≤1 CFU/ml for Neisseria gonorrhoeae (NG). Using clinical specimens, the overall percent agreement with the Cobas ® 4800 CT/NG Test was >98.5%. Across urogenital specimens, there were 93 discrepant specimens; 76 (93.8%) of 81 CT discrepant specimens were 6800+/4800- and 10 (83.3%) of 12 NG discrepant specimens were 6800+/4800-. Sequencing verified CT results for 45 (61.6%) of 73 samples positive by 6800 and 1 (20%) of 5 positive by 4800. Similarly, 7 (70.0%) of 10 NG samples positive by 6800 and 1 of 2 positive by 4800 were confirmed by sequencing. Among discrepant extragenital specimens (all 6800+/4800-), 7 (50%) of 14 oropharyngeal and 23 (76.7%) of 30 anorectal CT discordant samples were confirmed as CT positive by sequencing; all 8 anorectal and 20 (90.9%) of 22 oropharyngeal NG discordant results were also confirmed as NG positive. In conclusion, Cobas ® CT/NG for use on the Cobas ® 6800/8800 Systems provides high-throughput automated solutions for sexually transmitted infection (STI) screening programs.

Residual stress state in pipe cut ring specimens for fracture toughness testing

Energy Technology Data Exchange (ETDEWEB)

Damjanovic, Darko [J.J. Strossmayer Univ. of Osijek, Slavonski Brod (Croatia). Mechanical Engineering Faculty; Kozak, Drazan [Zagreb Univ. (Croatia). Dept. for Mechanical Design; Marsoner, Stefan [Materials Center, Leoben (Austria).; Gubeljak, Nenad [Maribor Univ. (Slovenia). Chair of Mechanics

2017-07-01

Thin-walled pipes are not suitable for measuring fracture toughness parameters of vital importance because longitudinal crack failure is the most common failure mode in pipes. This is due to the impossibility to manufacture standard specimens for measuring fracture toughness, such as SENB or CT specimens, from the thin wall of the pipe. Previous works noticed this problem, but until now, a good and convenient solution has not been found or developed. To overcome this problem, very good alternative solution was proposed, the so-called pipe ring notched bend specimen (PRNB) [1-5]. Until now, only the idealized geometry PRNB specimen is analyzed, i. e., a specimen which is not cut out from an actual pipe but produced from steel plate. Based on that, residual stresses are neglected along with the imperfections in geometry (elliptical and eccentricity). The aim of this research is to estimate the residual stress state(s) in real pipes used in the boiler industry produced by hot rolling technique. These types of pipes are delivered only in normalized condition, but not stress relieved. Therefore, there are residual stresses present due to the manufacturing technique, but also due to uneven cooling after the production process. Within this paper, residual stresses are estimated by three methods: the incremental hole drilling method (IHMD), X-ray diffraction (XRD) and the splitting method (SM). Knowing the residual stress state in the ring specimen, it is possible to assess their impact on fracture toughness measured on the corresponding PRNB specimen(s).

Residual stress state in pipe cut ring specimens for fracture toughness testing

International Nuclear Information System (INIS)

Damjanovic, Darko; Kozak, Drazan; Marsoner, Stefan; Gubeljak, Nenad

2017-01-01

Thin-walled pipes are not suitable for measuring fracture toughness parameters of vital importance because longitudinal crack failure is the most common failure mode in pipes. This is due to the impossibility to manufacture standard specimens for measuring fracture toughness, such as SENB or CT specimens, from the thin wall of the pipe. Previous works noticed this problem, but until now, a good and convenient solution has not been found or developed. To overcome this problem, very good alternative solution was proposed, the so-called pipe ring notched bend specimen (PRNB) [1-5]. Until now, only the idealized geometry PRNB specimen is analyzed, i. e., a specimen which is not cut out from an actual pipe but produced from steel plate. Based on that, residual stresses are neglected along with the imperfections in geometry (elliptical and eccentricity). The aim of this research is to estimate the residual stress state(s) in real pipes used in the boiler industry produced by hot rolling technique. These types of pipes are delivered only in normalized condition, but not stress relieved. Therefore, there are residual stresses present due to the manufacturing technique, but also due to uneven cooling after the production process. Within this paper, residual stresses are estimated by three methods: the incremental hole drilling method (IHMD), X-ray diffraction (XRD) and the splitting method (SM). Knowing the residual stress state in the ring specimen, it is possible to assess their impact on fracture toughness measured on the corresponding PRNB specimen(s).

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.

Effect of surface roughness on ultrasonic echo amplitude in aluminium-copper alloy castings

International Nuclear Information System (INIS)

Ambardar, R.; Pathak, S.D.; Prabhakar, O.; Jayakumar, T.

1996-01-01

In the present investigation, the influence of test surface roughness on ultrasonic back-wall echo (BWE) amplitude in Al-4.5%Cu alloy cast specimens has been studied. The results indicate that as the value of surface roughness of the specimen increases, the value of relating BWE amplitude at a given probe frequency decreases. However, under the present set of experimental conditions, the decrease in BWE amplitude with the increase in surface roughness of the test specimen is found to be appreciable at 10 MHz probe frequency. (author)

Comparison of analysis and experimental data for a unique crack arrest specimen

International Nuclear Information System (INIS)

Ayres, D.J.; Fabi, R.J.; Schonenberg, R.Y.; Norris, D.M.

1988-01-01

A new fracture test specimen has been developed to study crack extension and arrest in nuclear reactor vessel steels subject to stress-intensity factor and toughness gradients similar to those in postulated pressurized thermal shock situations. A summary of the results of all the tests performed is presented to illustrate the range of crack arrest and crack reinitiation conditions observed. One test of this specimen with the corresponding stress analysis is described in detail. During this test the crack initiated, extended, arrested, reinitiated, extended again, and reached a final arrest. Comparison of detailed dynamic elastic-plastic finite-element analyses and dynamic strain and displacement measurements of the crack extension, arrest, and reinitiation events, combined with topographic analysis of the future surfaces, has led to a new understanding of the crack extension and arrest process. The results of the tests demonstrate crack arrest in rising stress-intensity field at near-upper-shelf temperature conditions and show that the toughness required for arrest is lower than would be predicted by the analysis procedures usually employed for pressurized thermal shock evaluations

Advanced Mechanical Testing of Sandwich Materials

DEFF Research Database (Denmark)

Hayman, Brian; Berggreen, Christian; Jenstrup, Claus

2008-01-01

An advanced digital optical system has been used to measure surface strains on sandwich face and core specimens tested in a project concerned with improved criteria for designing sandwich X-joints. The face sheet specimens were of glass reinforced polyester and were tested in tension. The core sp...

Light transmittance and surface roughness of a feldspathic ceramic CAD-CAM material as a function of different surface treatments.

Science.gov (United States)

Ural, Çağrı; Duran, İbrahim; Evmek, Betül; Kavut, İdris; Cengiz, Seda; Yuzbasioglu, Emir

2016-07-15

The aim of the present study was to determine the effect of different surface treatments on light transmission of aesthetic feldspathic ceramics used in CAD-CAM chairside restorations. Forty eight feldspatic ceramic test specimens were prepared from prefabricated CAD-CAM blocks by using a slow speed diamond saw. Test specimens were prepared and divided into 4 groups (n = 12). In the control group, no surface treatments were applied on the feldspathic ceramic surfaces. In the hydrofluoric acid group, the bonding surfaces of feldspathic ceramics were etched with 9.5 % hydrofluoric acid. In the sandblasting group the feldspathic ceramic surfaces were air-abraded with 30-μm alumium oxide (Al2O3) particles and Er:YAG laser was used to irradiate the ceramic surfaces. The incident light power given by the LED device and the transmitted light power through each ceramic sample was registered using a digital LED radiometer device. Each polymerization light had a light guide with 8-mm-diameter tips. Light transmission of feldspathic ceramic samples was determined by placing it on the radiometer and irradiating the specimen for 10 s at the highest setting for each light polymerization. All specimens were coated with gold using a sputter coater and examined under a field emission scanning electron microscope. Surface roughness measurement each group were evaluated with 3D optical surface and tactile profilometers. One-way ANOVA test results revealed that both surface conditioning method significantly affect the light transmittance (F:412.437; p ceramic material below the value of 400 mW/cm(2) which is critical limit for safe polymerization.

A study on preparation of cross sectional anatomy specimen of cadaver

International Nuclear Information System (INIS)

Im, C. K.; Choi, B. I.; Park, J. H.; Chang, K. H.; Yeon, K. M.; Han, M. C.; Kim, C. W.

1984-01-01

With the advent of cross sectional image of CT, ultrasound and magnetic resonance, the need for knowledge of cross sectional anatomy is stranger than ever. To meet this need, preparation of cross sectional anatomy specimen using cadaver is indispensable, not only because it tis the real cut surface anatomy but also because overt limitations of radiographic image in both contrast and special resolution. Authors prepared cross sectional anatomy specimen using a male cadaver, comprising photographs and slides of the 60 cross cut slices from the head to the pelvis. After photography, each slices was embedded using transparent resin allowing permanent preservation of specimen without altering its original architecture. Author's unique method of preparation is presented and 4 representative specimens are illustrated comparing cadaver's CT image, cross cut surface photography, and photography of resin embedded slice of the same cut surface.

Standard Practice for Recording Data from Atmospheric Corrosion Tests of Metallic-Coated Steel Specimens

CERN Document Server

American Society for Testing and Materials. Philadelphia

2010-01-01

1.1 This practice covers a procedure for recording data of atmospheric corrosion tests of metallic-coated steel specimens. Its objective is the assurance of (1) complete identification of materials before testing, (2) objective reporting of material appearance during visual inspections, and (3) adequate photographic, micrographic, and chemical laboratory examinations at specific stages of deterioration, and at the end of the tests. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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.

Time-dependent leak behavior of flawed Alloy 600 tube specimens at constant pressure

Energy Technology Data Exchange (ETDEWEB)

Bahn, Chi Bum, E-mail: bahn@anl.gov [Argonne National Laboratory, Argonne, IL 60439 (United States); Majumdar, Saurin [Argonne National Laboratory, Argonne, IL 60439 (United States); Harris, Charles [United States Nuclear Regulatory Commission, Rockville, MD 20852 (United States)

2011-10-15

Leak rate testing has been performed using Alloy 600 tube specimens with throughwall flaws. Some specimens have shown time-dependent leak behavior at constant pressure conditions. Fractographic characterization was performed to identify the time-dependent crack growth mechanism. The fracture surface of the specimens showed the typical features of ductile fracture, as well as the distinct crystallographic facets, typical of fatigue crack growth at low {Delta}K level. Structural vibration appears to have been caused by the oscillation of pressure, induced by a high-pressure pump used in a test facility, and by the water jet/tube structure interaction. Analyses of the leak behaviors and crack growth indicated that both the high-pressure pump and the water jet could significantly contribute to fatigue crack growth. To determine whether the fatigue crack growth during the leak testing can occur solely by the water jet effect, leak rate tests at constant pressure without the high-pressure pump need to be performed. - Highlights: > Leak rate of flawed Alloy 600 tubing increased at constant pressure condition. > Fractography revealed two cases: ductile tearing and crystallographic facets. > Crystallographic facets are typical features of fatigue crack growth at low {Delta}K. > Fatigue source could be water jet-induced vibration and/or high-pressure pump pulsation.

The Statistic Test on Influence of Surface Treatment to Fatigue Lifetime with Limited Data

OpenAIRE

Suhartono, Agus

2009-01-01

Justifications on the influences of two or more parameters on fatigue strength are some times problematic due to the scatter nature of the fatigue data. Statistic test can facilitate the evaluation, whether the changes in material characteristics as a result of specific parameters of interest is significant. The statistic tests were applied to fatigue data of AISI 1045 steel specimens. The specimens are consisted of as received specimen, shot peened specimen with 15 and 16 Almen intensity as ...

Liquid salt environment stress-rupture testing

Science.gov (United States)

Ren, Weiju; Holcomb, David E.; Muralidharan, Govindarajan; Wilson, Dane F.

2016-03-22

Disclosed herein are systems, devices and methods for stress-rupture testing selected materials within a high-temperature liquid salt environment. Exemplary testing systems include a load train for holding a test specimen within a heated inert gas vessel. A thermal break included in the load train can thermally insulate a load cell positioned along the load train within the inert gas vessel. The test specimen can include a cylindrical gage portion having an internal void filled with a molten salt during stress-rupture testing. The gage portion can have an inner surface area to volume ratio of greater than 20 to maximize the corrosive effect of the molten salt on the specimen material during testing. Also disclosed are methods of making a salt ingot for placement within the test specimen.

Predicting crack instability behavior of burst tests from small specimens for irradiated Zr-2.5Nb pressure tubes

International Nuclear Information System (INIS)

Davies, P.H.

1997-01-01

A scaling approach, based on the deformation J-integral at maximum load obtained from small specimens, is proposed for predicting the crack instability behavior of burst tests on irradiated Zr-2.5Nb pressure tubes. An assessment of this approach is carried out by comparison with other toughness criteria such as the modified J-integral and the plastic work dissipation rate approach. The largest discrepancy between the different parameters occurs for materials of intermediate toughness which exhibit the most stable crack growth and tunnelling up to maximum load. A study of one material of intermediate toughness suggests crack-front tunnelling has a significant influence on the results obtained from the 17-mm-wide specimens. It is shown that for a tube of intermediate toughness the different approaches can significantly underpredict the extent of stable crack growth before instability in a burst test even after correcting for tunnelling. The usefulness of a scaling approach in reducing the discrepancy between the small- and large-scale specimen results for this material is demonstrated

Grips for testing of electrical characteristics of a specimen under a mechanical load

Science.gov (United States)

Briggs, Timothy; Loyola, Bryan

2018-04-24

Various technologies to facilitate coupled electrical and mechanical measurement of conductive materials are disclosed herein. A gripping device simultaneously holds a specimen in place and causes contact to be made between the specimen and a plurality of electrodes connected to an electrical measuring device. An electrical characteristic of the specimen is then measured while a mechanical load is applied to the specimen, and a relationship between the mechanical load and changes in the electrical characteristic can be identified.

Crack propagation tests on the fundamental structure under cyclic thermal transients. Results of nondestructive inspection for cracks

International Nuclear Information System (INIS)

Kobayashi, S.; Horikiri, M.

2001-06-01

This report shows the results of crack inspection in crack propagation tests that were carried out at the Air-cooling Thermal Transient Test Facility (ATTF). Test specimens were made of 304 type austenitic stainless steel, and they were the same cylindrical shape, 1,500 mm in height, 130 mm in outer diameter and 30 mm in thickness. And they had initial slits machined on inner surfaces. Firstly the specimens were heated up to 650degC in a furnace, then cooled by pressurized air blowing through the specimen for 90 seconds. These cyclic changes of temperature gradients in the wall of specimens were loaded. Specimens were tested for several years. The specimen No. CPTT-102 with machined two circumferential slits and two semi-elliptical slits was tested up to 10,000 cycles. And the specimen No. CPTT-103 with machined six semi-elliptical slits of different length respectively was tested up to 5,000 cycles. Cracks of specimens were inspected nondestructively for a giving cycle in these tests. Applied inspection methods were ultra-sonic testing, potential-drop method and inner surface observation. Ultra-sonic testing was carried out by applying the pulse-echo method. Potential-drop testing was carried out by measurement of localized constant direct current beyond cracks. Photographs of the inner surface of specimens were taken using a bore-scope. The results of ultra-sonic testing have been close to destructive test results. The depth of crack by the potential-drop method was almost corresponding to destructive test results, too. Photographs of the inner surface were synthesized by the computer, and connection between main crack and hair crack was observed. (author)

Examination of cadmium safety rod thermal test specimens and failure mechanism evaluation

International Nuclear Information System (INIS)

Thomas, J.K.; Peacock, H.B.; Iyer, N.C.

1992-01-01

The reactor safety rods may be subjected to high temperatures due to gamma heating after the core coolant level has dropped during the ECS phase of a hypothetical LOCA event. Accordingly, an experimental cadmium safety rod testing subtask was established as part of a task to address the response of reactor core components to this accident. Companion reports describe the experiments and a structural evaluation (finite element analysis) of the safety rod. This report deals primarily with the examination of the test specimens, evaluation of possible failure mechanisms, and confirmatory separate effects experiments. It is concluded that the failures observed in the cadmium safety rod thermal tests which occurred at low temperature (T 800 degrees C) with fast thermal ramp rates are concluded to be mechanical in nature without significant environmental degradation. Based on these tests, tasks were initiated to design and manufacture B 4 C safety rods to replace the cadmium safety rods. The B 4 C safety rods have been manufactured at this time and it is currently planned to charge them to the reactor in the near future. 60 refs

qPCR-High resolution melt analysis for drug susceptibility testing of Mycobacterium leprae directly from clinical specimens of leprosy patients.

Science.gov (United States)

Araujo, Sergio; Goulart, Luiz Ricardo; Truman, Richard W; Goulart, Isabela Maria B; Vissa, Varalakshmi; Li, Wei; Matsuoka, Masanori; Suffys, Philip; Fontes, Amanda B; Rosa, Patricia S; Scollard, David M; Williams, Diana L

2017-06-01

Real-Time PCR-High Resolution Melting (qPCR-HRM) analysis has been recently described for rapid drug susceptibility testing (DST) of Mycobacterium leprae. The purpose of the current study was to further evaluate the validity, reliability, and accuracy of this assay for M. leprae DST in clinical specimens. The specificity and sensitivity for determining the presence and susceptibility of M. leprae to dapsone based on the folP1 drug resistance determining region (DRDR), rifampin (rpoB DRDR) and ofloxacin (gyrA DRDR) was evaluated using 211 clinical specimens from leprosy patients, including 156 multibacillary (MB) and 55 paucibacillary (PB) cases. When comparing the results of qPCR-HRM DST and PCR/direct DNA sequencing, 100% concordance was obtained. The effects of in-house phenol/chloroform extraction versus column-based DNA purification protocols, and that of storage and fixation protocols of specimens for qPCR-HRM DST, were also evaluated. qPCR-HRM results for all DRDR gene assays (folP1, rpoB, and gyrA) were obtained from both MB (154/156; 98.7%) and PB (35/55; 63.3%) patients. All PCR negative specimens were from patients with low numbers of bacilli enumerated by an M. leprae-specific qPCR. We observed that frozen and formalin-fixed paraffin embedded (FFPE) tissues or archival Fite's stained slides were suitable for HRM analysis. Among 20 mycobacterial and other skin bacterial species tested, only M. lepromatosis, highly related to M. leprae, generated amplicons in the qPCR-HRM DST assay for folP1 and rpoB DRDR targets. Both DNA purification protocols tested were efficient in recovering DNA suitable for HRM analysis. However, 3% of clinical specimens purified using the phenol/chloroform DNA purification protocol gave false drug resistant data. DNA obtained from freshly frozen (n = 172), formalin-fixed paraffin embedded (FFPE) tissues (n = 36) or archival Fite's stained slides (n = 3) were suitable for qPCR-HRM DST analysis. The HRM-based assay was also able to

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.

Test surfaces useful for calibration of surface profilometers

Science.gov (United States)

Yashchuk, Valeriy V; McKinney, Wayne R; Takacs, Peter Z

2013-12-31

The present invention provides for test surfaces and methods for calibration of surface profilometers, including interferometric and atomic force microscopes. Calibration is performed using a specially designed test surface, or the Binary Pseudo-random (BPR) grating (array). Utilizing the BPR grating (array) to measure the power spectral density (PSD) spectrum, the profilometer is calibrated by determining the instrumental modulation transfer.

Analysis of surface hardness of artificially aged resin composites

Directory of Open Access Journals (Sweden)

Denise Cremonezzi Tornavoi

2012-02-01

Full Text Available This study evaluated the effect of artificially accelerated aging (AAA on the surface hardness of eight composite resins: Filtek Z250, Filtek Supreme, 4 Seasons, Herculite, P60, Tetric Ceram, Charisma, and Filtek Z100. Sixteen specimens were made from the test piece of each material, using an 8.0 × 2.0 mm teflon matrix. After 24 hours, eight specimens from each material were submitted to three surface hardness readings using a Shimadzu Microhardness Tester for 5 seconds at a load of 50 gf. The other eight specimens remained in the artificially accelerated aging machine for 382 hours and were submitted to the same surface hardness analysis. The means of each test specimen were submitted to the Kolmogorov-Smirnov test (p > 0.05, ANOVA and Tukey test (p < 0.05. With regard to hardness (F = 86.74, p < 0.0001 the analysis showed significant differences among the resin composite brands. But aging did not influence the hardness of any of the resin composites (F = 0.39, p = 0.53. In this study, there was interaction between the resin composite brand and the aging factors (F = 4.51, p < 0.0002. It was concluded that notwithstanding the type of resin, AAA did not influence surface hardness. However, with regard to hardness there was a significant difference among the resin brands.

Fracture toughness measurements with subsize disk compact specimens

International Nuclear Information System (INIS)

Alexander, D.J.

1994-01-01

Special fixtures and test methods have been developed for testing small disk compact specimens (1.25 mm diam by 4.6 mm thick). Specimens of European type 316L austenitic stainless steel were irradiated to damage levels of about 3 dpa at nominal irradiation temperatures of either 90 or 250 C and tested over a temperature range from 20 to 250 C. Results show that irradiation to this dose level at these temperatures reduces the fracture toughness but the toughness remains quite high. The toughness decreases as the test temperature increases. Irradiation at 250 C is more damaging than at 90 C, causing larger decreases in the fracture toughness. The testing shows that it is possible to generate useful fracture toughness data with a small disk compact specimens

Direct observation of asperity deformation of specimens with random rough surfaces in upsetting and indentation processes

DEFF Research Database (Denmark)

Azushima, A.; Kuba, S.; Tani, S.

2006-01-01

The trapping behavior of liquid lubricant and contact behavior of asperities at the workpiece-tool interface during upsetting and indentation are observed directly using a compression subpress which consists of a transparent die made of sapphire, a microscope with a CCD camera and a video system....... The experiments are carried out without lubricant and with lubricant. Specimens used are commercially pure A1100 aluminum with a random rough surface. From these observations, the change in the fraction of real contact area is measured by an image processor. The real contact area ratios in upsetting experiments...

Surface Coating of Gypsum-Based Molds for Maxillofacial Prosthetic Silicone Elastomeric Material: The Surface Topography.

Science.gov (United States)

Khalaf, Salah; Ariffin, Zaihan; Husein, Adam; Reza, Fazal

2015-07-01

This study aimed to compare the surface roughness of maxillofacial silicone elastomers fabricated in noncoated and coated gypsum materials. This study was also conducted to characterize the silicone elastomer specimens after surfaces were modified. A gypsum mold was coated with clear acrylic spray. The coated mold was then used to produce modified silicone experimental specimens (n = 35). The surface roughness of the modified silicone elastomers was compared with that of the control specimens, which were prepared by conventional flasking methods (n = 35). An atomic force microscope (AFM) was used for surface roughness measurement of silicone elastomer (unmodified and modified), and a scanning electron microscope (SEM) was used to evaluate the topographic conditions of coated and noncoated gypsum and silicone elastomer specimens (unmodified and modified) groups. After the gypsum molds were characterized, the fabricated silicone elastomers molded on noncoated and coated gypsum materials were evaluated further. Energy-dispersive X-ray spectroscopy (EDX) analysis of gypsum materials (noncoated and coated) and silicone elastomer specimens (unmodified and modified) was performed to evaluate the elemental changes after coating was conducted. Independent t test was used to analyze the differences in the surface roughness of unmodified and modified silicone at a significance level of p SEM analysis results showed evident differences in surface smoothness. EDX data further revealed the presence of the desired chemical components on the surface layer of unmodified and modified silicone elastomers. Silicone elastomers with lower surface roughness of maxillofacial prostheses can be obtained simply by coating a gypsum mold. © 2014 by the American College of Prosthodontists.

Development of reconstitution technique of irradiated specimens. 3. Report for FY 1995 and FY 1996 on JAERI-IHI cooperated research program (joint research)

Energy Technology Data Exchange (ETDEWEB)

Nishiyama, Yutaka; Fukaya, Kiyoshi; Onizawa, Kunio; Suzuki, Masahide [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nakamura, Terumi; Kaihara, Shoichiro; Yoshida, Kazuo; Sato, Akira

1998-10-01

The cooperated research between Japan Atomic Energy Research Institute and Ishikawajima-Harima Heavy Industries Co., Ltd. on the development of reconstitution technique of irradiated reactor pressure vessel surveillance specimens has been performed from FY 1993. In FY 1993-1994, the method of surface activated joining (SAJ) was applied to reconstitution of Charpy impact specimens. Some verification tests using unirradiated reactor pressure vessel plate materials have shown that SAJ is feasible for a reconstitution technique, in particular, owing to low joining temperature. The present paper reports the results of the cooperated research performed in FY 1995-1996. To improve the quality of the SAJ, the configuration of the end tab surface to be joined with the insert material was modified. The torque measured during joining was also introduced in joining parameters. A nondestructive inspection, temperature measurements in the specimens during joining were performed. The effect of joining on Charpy impact properties was discussed. For practical application of the technique to irradiated specimens, we confirmed that the impact specimens with joining interface gave rise to no failure at the joining position during impact test after neutron irradiation. (author)

Automatic grinding apparatus to control uniform specimen thicknesses

Science.gov (United States)

Bryner, Joseph S.

1982-01-01

This invention is directed to a new and improved grinding apparatus comprising (1) a movable grinding surface, (2) a specimen holder, (3) a displacing device for moving the holder and/or grinding surface toward one another, and (4) at least three devices for limiting displacement of the holder to the grinding surface.

An automated tensile machine for small specimens heavily neutron irradiated in FFTF/MOTA

International Nuclear Information System (INIS)

Kohyama, Akira; Sato, Shinji; Hamada, Kenichi

1993-01-01

The objective of this work is to develop a fully automated tensile machine for post-irradiation examination (PIE) of Fast Flux Test Facility (FFTF)/Materials Open Test Assembly (MOTA) irradiated miniature tension specimens. The anticipated merit of the automated tensile machine is to reduce damage to specimens during specimen handling for PIE and to reduce exposure to radioactive specimens. This machine is designed for testing at elevated temperatures, up to 873 K, in a vacuum or in an inert gas environment. Twelve specimen assemblies are placed in the vacuum chamber that can be tested successively in a fully automated manner. A unique automated tensile machine for the PIE of FFTF/MOTA irradiated specimens, the Monbusho Automated Tensile Machine (MATRON) consists of a test frame with controlling units and an automated specimen-loading apparatus. The qualification of the test frame has been completed, and the results have satisfied the machine specifications. The capabilities of producing creep and relaxation data have been demonstrated for Cu, Al, 316SS, and ferritic steels. The specimen holders for the three-point bending test and the small bulge test (small punch test; SP test) were also designed and produced

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...

Strength evaluation test of pressureless-sintered silicon nitride at room temperature

Science.gov (United States)

Matsusue, K.; Takahara, K.; Hashimoto, R.

1984-01-01

In order to study strength characteristics at room temperature and the strength evaluating method of ceramic materials, the following tests were conducted on pressureless sintered silicon nitride specimens: bending tests, the three tensile tests of rectangular plates, holed plates, and notched plates, and spin tests of centrally holed disks. The relationship between the mean strength of specimens and the effective volume of specimens are examined using Weibull's theory. The effect of surface grinding on the strength of specimens is discussed.

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)

Sem-observation of developing plant organs using deep-frozen specimens

NARCIS (Netherlands)

NN,

1982-01-01

The SEM-observation of plant material normally requires dehydrated, dry specimens coated with carbon or metal. Unfortunately, the standard drying methods (including the critical-point-drying-technique) often cause shrinking and deformation of the specimen surface; therefore, SEMstudies on plant

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.

Irradiation of UO2 specimens with molten cores in a pressurized water loop. Test X-2-x

International Nuclear Information System (INIS)

Bain, A.S.

1961-08-01

Two Zircaloy-2 clad specimens containing stoichiometric UO 2 pellets were irradiated in a pressurized water loop for 379 hours at heat ratings sufficient to cause central melting of the UO 2 . There was no appearance of localized overheating or accelerated corrosion of the sheath, but the diametral increases were considerably larger than those observed in loop specimens irradiated at lower heat ratings. The length increases, however, were approximately the same as those measured for specimens at lower ratings. There was a clearly visible demarcation between UO 2 that had been molten and that which had not. The value of ∫ 500 o C Tm kdθ = 74 ± W/cm was essentially the same as that obtained from the short-duration tests in the Hydraulic Rabbit, indicating there is no marked decrease in thermal conductivity of the UO 2 fuel in irradiations up to 379 hours. (author)

Evaluation of Mechanical Property of Carbon Fiber/Polypropylene Composite According to Carbon Fiber Surface Treatment

International Nuclear Information System (INIS)

Han, Song Hee; Oh, Hyun Ju; Kim, Seong Su

2013-01-01

In this study, the mechanical properties of a carbon fiber/polypropylene composite were evaluated according to the carbon fiber surface treatment. Carbon fiber surface treatments such as silane coupling agents and plasma treatment were performed to enhance the interfacial strength between carbon fibers and polypropylene. The treated carbon fiber surface was characterized by XP S, Sem, and single-filament tensile test. The interlaminar shear strength (Ilks) of the composite with respect to the surface treatment was determined by a short beam shear test. The test results showed that the Ilks of the plasma-treated specimen increased with the treatment time. The Ilks of the specimen treated with a silane coupling agent after plasma treatment increased by 48.7% compared to that of the untreated specimen

Ductility and failure behaviour of both unirradiated and irradiated zircaloy-4 cladding using plane strain tensile specimens

International Nuclear Information System (INIS)

Carassou, S.; Le Saux, M.; Pizzanelli, J.P.; Rabouille, O.; Averty, X.; Poussard, C.; Cazalis, B.; Desquines, J.; Bernaudat, C.

2010-01-01

In this work, eight PST (Plan Strain Tensile) tests machined from a Zircaloy-4 (Zy-4) cladding irradiated up to 5 annual cycles have been performed at 280, 350 and 480 Celsius degrees. The specimen displacements during the tests were filmed and digitally recorded to allow the use of a Digital Image Correlation (DIC) analysis technique to experimentally determine the local strains on the outer surface of the specimens. The plane strain conditions have been verified and prevail over a wide area between the notches of the specimen, as expected from full 3D FE numerical analysis performed in support of the tests. For the first time, the location of the onset of fracture for this geometry on irradiated material has been experimentally observed: at 280 C.degrees, crack initiates in the vicinity of the notches, in an area where plane strain conditions are not fulfilled, and for a local circumferential strain value of about 5%. At 350 C. degrees and 480 C. degrees, cracks initiate at a location where plane strain conditions prevail, for circumferential strain values respectively close to 10% and greater than 50%. These results have been compared to results obtained previously by similar test on fresh and hydrided material, as well as tests performed as support to the study. At 350 C. degrees, the homogeneous 700 ppm hydrided Zy-4 and the Zy-4 irradiated during 5 annual cycles exhibit similar fracture behaviour, for both fracture hoop strain values (10%) and fracture mode (through-wall slant fracture). For the irradiated material, it has clearly been established that at 350 C. degrees, a brittle fracture occurs at the outer surface in the hydride rim. The crack propagates subsequently toward the inner surface and the notches, where final fracture occurs

Adhesive bonding of resin composite to various titanium surfaces using different metal conditioners and a surface modification system

Directory of Open Access Journals (Sweden)

Hercules Jorge ALMILHATTI

2013-12-01

Full Text Available Objective: This study evaluated the effect of three metal conditioners on the shear bond strength (SBS of a prosthetic composite material to cpTi grade I having three surface treatments. Material and Methods: One hundred sixty eight rivet-shaped specimens (8.0x2.0 mm were cast and subjected to polishing (P or sandblasting with either 50 mm (50SB or 250 mm (250SB Al2O3. The metal conditioners Metal Photo Primer (MPP, Cesead II Opaque Primer (OP, Targis Link (TL, and one surface modification system Siloc (S, were applied to the specimen surfaces, which were covered with four 1-mm thick layers of resin composite. The resin layers were exposed to curing light for 90 s separately. Seven specimens from each experimental group were stored in water at 37ºC for 24 h while the other 7 specimens were subjected to 5,000 thermal cycles consisting of water baths at 4ºC and 60ºC (n=7. All specimens were subjected to SBS test (0.5 mm/min until failure occurred, and further 28 specimens were analyzed using scanning electron microscope (SEM and X-ray energy-dispersive spectroscopy (EDS. Data were analyzed by 3-way ANOVA followed by post-hoc Tukey's test (α=0.05. Results: On 50SB surfaces, OP groups showed higher SBS means than MPP (P<0.05, while no significant difference was found among OP, S, and TL groups. On 250SB surfaces, OP and TL groups exhibited higher SBS than MPP and S (P<0.05. No significant difference in SBS was found between OP and TL groups nor between MPP and S groups. The use of conditioners on 250SB surfaces resulted in higher SBS means than the use of the same products on 50SB surfaces (P<0.05. Conclusion: Sandblasting associated with the use of metal conditioners improves SBS of resin composites to cpTi.

Optimal design and fabrication of three-dimensional calibration specimens for scanning probe microscopy

Energy Technology Data Exchange (ETDEWEB)

Liu Xiaoning; Luo Tingting; Chen Yuhang; Huang Wenhao [Department of Precision Machinery and Instrumentation, University of Science and Technology of China, 230026 Hefei (China); Piaszenski, Guido [Raith GmbH, Konrad-Adenauer-Allee 8, 44263 Dortmund (Germany)

2012-05-15

Micro-/nano-scale roughness specimens are highly demanded to synthetically calibrate the scanning probe microscopy (SPM) instrument. In this study, three-dimensional (3D) specimens with controllable main surface evaluation parameters were designed. In order to improve the design accuracy, the genetic algorithm was introduced into the conventional digital filter method. A primary 3D calibration specimen with the dimension of 10 {mu}m x 10 {mu}m was fabricated by electron beam lithography. Atomic force microscopy characterizations demonstrated that the statistical and spectral parameters of the fabricated specimen match well with the designed values. Such a kind of 3D specimens has the potential to calibrate the SPM for applications in quantitative surface evaluations.

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.

Quantification of Applied Stresses of C-Ring Specimens for Stress Corrosion Cracking Tests

International Nuclear Information System (INIS)

Kim, Woo Gon; Kim, Sun Jae; Rhee, Chang Kyu; Kuk, Il Hiun; Choi, Jong Ho

1997-01-01

For comparing their resistances for stress-corrosion cracking(SCC) in the K600-MA, K690-MA, and K600-TT tubes, C-ring specimens were fabricated with the various thermal-treatments to control the distributions of the precipitates like Cr-carbides. The bending stresses were analyzed to determine the amounts to make the stress quantitatively to all the C-ring samples, and then the stresses were calculated with the relation to the outer diameter(O.D) deflection(δ) of the C-rings. To measure accurately the bending strains of the C-ring specimens, the strain gauges were used and the compression test was also carried out. In the elastic region, the stresses in both the transverse and the circumferential directions were different with the locations of the strain gauges as attached at α= 30 .deg., 45 .deg., and 90 .deg. to the principal stress direction, but those in the longitudinal direction were independent of their attached locations. Calculated stresses from the strains obtained using the strain gauges were well agreed with the theoretical. In the plastic region over δ=1.0mm, the stresses for the TT tubes showed lower values of about 400MPa than those for the MA tubes. However, the stresses among the TT tubes showed almost the similar values in this region. Therefore, the states of the stresses applied to the C-ring specimens would be different with the material conditions, i.e, the chemical compositions, the thermal treatments such as MA and TT

Tensile bond strength of metal bracket bonding to glazed ceramic surfaces with different surface conditionings.

Science.gov (United States)

Akhoundi, Ms Ahmad; Kamel, M Rahmati; Hashemi, Sh Mahmood; Imani, M

2011-01-01

The objective of this study was to compare the tensile bond strength of metal brackets bonding to glazed ceramic surfaces using three various surface treatments. Forty two glazed ceramic disks were assigned to three groups. In the first and second groups the specimens were etched with 9.5% hydrofluoric acid (HFA). Subsequently in first group, ceramic primer and adhesive were applied, but in second group a bonding agent alone was used. In third group, specimens were treated with 35% phosphoric acid followed by ceramic primer and adhesive application. Brackets were bonded with light cure composites. The specimens were stored in distilled water in the room temperature for 24 hours and thermocycled 500 times between 5°C and 55°C. The universal testing machine was used to test the tensile bond strength and the adhesive remenant index scores between three groups was evaluated. The data were subjected to one-way ANOVA, Tukey and Kruskal-Wallis tests respectively. The tensile bond strength was 3.69±0.52 MPa forfirst group, 2.69±0.91 MPa for second group and 3.60±0.41 MPa for third group. Group II specimens showed tensile strength values significantly different from other groups (Ptensile bond strength.

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

Charpy impact test results on five materials and NIST verification specimens using instrumented 2-mm and 8-mm strikers

International Nuclear Information System (INIS)

Nanstad, R.K.; Sokolov, M.A.

1995-01-01

The Heavy-Section Steel Irradiation Program at Oak Ridge National Laboratory is involved in two cooperative projects, with international participants, both of which involve Charpy V-notch impact tests with instrumented strikers of 2mm and 8mm radii. Two heats of A 533 grade B class I pressure vessel steel and a low upper-shelf (LUS) submerged-arc (SA) weld were tested on the same Charpy machine, while one heat of a Russian Cr-Mo-V forging steel and a high upper-shelf (HUS) SA weld were tested on two different machines. The number of replicate tests at any one temperature ranged from 2 to 46 specimens. Prior to testing with each striker, verification specimens at the low, high, and super high energy levels from the National Institute of Standards and Technology (NIST) were tested. In the two series of verification tests, the tests with the 2mm striker met the requirements at the low and high energy levels but not at the super high energy. For one plate, the 2mm striker showed somewhat higher average absorbed energies than those for the 8-mm striker at all three test temperatures. For the second plate and the LUS weld, however, the 2mm striker showed somewhat lower energies at both test temperatures. For the Russian forging steel and the HUS weld, tests were conducted over a range of temperatures with tests at one laboratory using the 8mm striker and tests at a second laboratory using the 2mm striker. Lateral expansion was measured for all specimens and the results are compared with the absorbed energy results. The overall results showed generally good agreement (within one standard deviation) in energy measurements by the two strikers. Load-time traces from the instrumented strikers were also compared and used to estimate shear fracture percentage. Four different formulas from the European Structural Integrity Society draft standard for instrumented Charpy test are compared and a new formula is proposed for estimation of percent shear from the force-time trace

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.

Shear compression testing of glass-fibre steel specimens after 4K reactor irradiation: Present status and facility upgrade

International Nuclear Information System (INIS)

Gerstenberg, H.; Kraehling, E.; Katheder, H.

1997-01-01

The shear strengths of various fibre reinforced resins being promising candidate insulators for superconducting coils to be used tinder a strong radiation load, e.g. in future fusion reactors were investigated prior and subsequent to reactor in-core irradiation at liquid helium temperature. A large number of sandwich-like (steel-bonded insulation-steel) specimens representing a widespread variety of materials and preparation techniques was exposed to irradiation doses of up to 5 x 10 7 Gy in form of fast neutrons and γ-radiation. In a systematic study several experimental parameters including irradiation dose, postirradiation storage temperature and measuring temperature were varied before the determination of the ultimate shear strength. The results obtained from the different tested materials are compared. In addition an upgrade of the in-situ test rig installed at the Munich research reactor is presented, which allows combined shear/compression loading of low temperature irradiated specimens and provides a doubling of the testing rate

Determination of necking time in tensile test specimens, under high-temperature creep conditions, subjected to distribution of stresses over the cross-section

Science.gov (United States)

Lokoshchenko, A.; Teraud, W.

2018-04-01

The work describes an experimental research of creep of cylindrical tensile test specimens made of aluminum alloy D16T at a constant temperature of 400°C. The issue to be examined was the necking at different values of initial tensile stresses. The use of a developed noncontacting measuring system allowed us to see variations in the specimen shape and to estimate the true stress in various times. Based on the obtained experimental data, several criteria were proposed for describing the point of time at which the necking occurs (necking point). Calculations were carried out at various values of the parameters in these criteria. The relative interval of deformation time in which the test specimen is uniformly stretched was also determined.

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...

Redesigning axial-axial (biaxial) cruciform specimens for very high cycle fatigue ultrasonic testing machines.

Science.gov (United States)

Montalvão, Diogo; Wren, Andrew

2017-11-01

The necessity to increase performances in terms of lifetime and security in mechanical components or structures is the motivation for intense research in fatigue. Applications range from aeronautics to medical devices. With the development of new materials, there is no longer a fatigue limit in the classical sense, where it was accepted that the fatigue limit is the stress level such that there is no fracture up to 1E7 cycles. The recent development of ultrasonic testing machines where frequencies can go as high as 20 kHz or over enabled tests to be extended to ranges larger than 1E9 in just a few days. This area of studies is now known as Very High Cycle Fatigue (VHCF). On the other hand, most of the existing test equipment in the market for both classical and VHCF are uniaxial test machines. However, critical components used in Engineering applications are usually subjected to complex multi-axial loading conditions. In this paper, it is presented the methodology to redesigning existing cruciform test specimens that can be used to create an in-plane biaxial state of stress when used in 'uniaxial' VHCF ultrasonic testing machines (in this case, the term 'uniaxial' is used not because of the state of stress created at the centre of the specimen, but because of the direction at which the load is applied). The methodology is explained in such a way that it can be expanded to other existing designs, namely cruciform designs, that are not yet used in VHCF. Also, although the approach is presented in simple and logical terms, it may not be that obvious for those who have a more focused approach on fatigue rather than on modal analysis. It is expected that by contributing to bridging the gap between the sciences of modal analysis and fatigue, this research will help and encourage others exploiting new capabilities in VHCF.

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...

9 CFR 93.204 - Import permits for poultry and for poultry test specimens for diagnostic purposes; and...

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Import permits for poultry and for poultry test specimens for diagnostic purposes; and reservation fees for space at quarantine facilities... SERVICE, DEPARTMENT OF AGRICULTURE EXPORTATION AND IMPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL...

Development of electric discharge equipment for small specimen sampling

International Nuclear Information System (INIS)

Okamoto, Koji; Kitagawa, Hideaki; Kusumoto, Junichi; Kanaya, Akihiro; Kobayashi, Toshimi

2009-01-01

We have developed the on-site electric discharge sampling equipment that can effectively take samples such as small specimens from the surface portion of the plant components. Compared with the conventional sampling equipment, our sampling equipment can take samples that are thinner in depth and larger in area. In addition, the affection to the equipment can be held down to the minimum, and the thermally-affected zone of the material due to electric discharge is small, which is to be ignored. Therefore, our equipment is excellent in taking samples for various tests such as residual life evaluation.

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.

Application Anti Microbial Activity Test and Direct Inoculation of Urinary Specimen Test to Increase the Quality of Results and Decrease the Production Cost in Clinical Microbiology Laboratory, Sanglah General Hospital Hospital, Bali-Indonesia

Directory of Open Access Journals (Sweden)

Nyoman Sri-Budayanti

2012-05-01

Full Text Available Objective: Urinary tract infection (UTI is the most common bacterial infection in general practice and in hospitals. Fast and accurate urine culture and sensitivity test are needed for adequate therapy. Anti Microbial Activity test (AMA test that is used to detect the presence of antibiotics in urine specimens is not commonly used in clinical microbiology laboratories. Some laboratories are still using indirect inoculation technique using enriched media before inoculating onto the agar media. The aim of this research is to compare results of urinary examination of direct inoculation technique with AMA test with indirect inoculation technique without AMA test.Methods: A number of 210 urine specimens were collected in Clinical Microbiology Laboratory at Sanglah General Hospital within a time period between 16 June until 16 July 2009.Results: Antibiotics were detected in 40% of the urinary specimens; whereas 48.1% showed no evidence of UTI, that is negative AMA test and sterile urinary culture or colony growth < 105 CFU/ml. Only 11.9% of the specimens indicates urinary tract infections. The examination can be completed within 2-3 days which is shorter than indirect inoculation test which require 5-7 days. Direct inoculation technique can reduce the cost of production three-fold the costs require for an indirect inoculation test.Conclusions: Application of AMA test and direct inoculation technique can give results more rapidly, reliable and useful for clinicians. This also decrease the laboratory’s cost of production.

Strain transfer through film-substrate interface and surface curvature evolution during a tensile test

Science.gov (United States)

He, Wei; Han, Meidong; Goudeau, Philippe; Bourhis, Eric Le; Renault, Pierre-Olivier; Wang, Shibin; Li, Lin-an

2018-03-01

Uniaxial tensile tests on polyimide-supported thin metal films are performed to respectively study the macroscopic strain transfer through an interface and the surface curvature evolution. With a dual digital image correlation (DIC) system, the strains of the film and the substrate can be simultaneously measured in situ during the tensile test. For the true strains below 2% (far beyond the films' elastic limit), a complete longitudinal strain transfer is present irrespective of the film thickness, residual stresses and microstructure. By means of an optical surface profiler, the three-dimensional (3D) topography of film surface can be obtained during straining. As expected, the profile of the specimen center remains almost flat in the tensile direction. Nevertheless, a relatively significant curvature evolution (of the same order with the initial curvature induced by residual stresses) is observed along the transverse direction as a result of a Poisson's ratio mismatch between the film and the substrate. Furthermore, finite element method (FEM) has been performed to simulate the curvature evolution considering the geometric nonlinearity and the perfect strain transfer at the interface, which agrees well with the experimental results.

Influence of citric acid on the surface texture of glass ionomer restorative materials.

Science.gov (United States)

Reddy, Dappili Swami Ranga; Kumar, Ramachandran Anil; Venkatesan, Sokkalingam Mothilal; Narayan, Gopal Shankar; Duraivel, Dasarathan; Indra, Rajamani

2014-09-01

This study determined the effectiveness of G-coat plus surface protective agent over petroleum jelly on the surface texture of conventional Glass ionomer restorative materials. Three chemically cured conventional glass ionomer restorative materials type II, type IX and ketac molar were evaluated in this study. Sixty specimens were made for each restorative material. They were divided into two groups of thirty specimens each. Of the sixty specimens, thirty were coated with G-coat plus (a nano-filler coating) and the rest with petroleum jelly. Thirty samples of both protective coating agents were randomly divided into six groups of five specimens and conditioned in citric acid solutions of differing pH (pH 2, 3, 4, 5, 6 & 7). Each specimen was kept in citric acid for three hours a day, and the rest of time stored in salivary substitute. This procedure was repeated for 8 days. After conditioning, the surface roughness (Ra, μm) of each specimen was measured using a surface profilometer (Taylor & Habson, UK). Data was analyzed using one-way analysis of variance (ANOVA) and Tukey's HSD test at a significance level of 0.05. The surface textures of all the tested glass ionomer restorative materials protected with G-coat plus were not significantly affected by acids at low pH. The surface textures of all the tested glass ionomer restorative materials protected with petroleum jelly coating were significantly affected by acids at low pH. The effects of pH on the surface texture of glass ionomer restoratives are material dependent. Among all the materials tested the surface texture of Type II GIC (Group I) revealed marked deterioration when conditioned in solutions of low pH and was statistically significant. Hence, a protective coating either with G-coat plus or with light polymerized low viscosity unfilled resin adhesives is mandatory for all the glass ionomer restorations to increase the wear resistance of the restorative materials.

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.

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)

Development of a strain measurement method for non-plane specimens by means of computer picture processing

International Nuclear Information System (INIS)

Yoshioka, Akira; Soneda, Naoki; Yagawa, Genki; Miyoshi, Akio.

1988-01-01

Integrity Tests of the Fast Breeder Reactor components are often conducted at an elevated temperature, say 550deg C. Since high-temperature strain measurement using special strain gauges is costly and unappropriate for large and repeated strains, the authors have developed an optical strain measurement method and system based on computer picture processing and the triangulation principle. The present method enables us to measure the strain in specimen with curved surfaces. Its operation is also easy, because of the automatic distinction of marks from noises. The verification tests with a plate specimen and a cylindrical one are performed under elevated temperatures. The results show that the present method is very suitable to the tests under elevated temperatures and that the measurement error of strain is within 0.2 % (2000μ), which is reasonable considering the limitation of hardware. (author)

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.

Surface-specific additive manufacturing test artefacts

Science.gov (United States)

Townsend, Andrew; Racasan, Radu; Blunt, Liam

2018-06-01

Many test artefact designs have been proposed for use with additive manufacturing (AM) systems. These test artefacts have primarily been designed for the evaluation of AM form and dimensional performance. A series of surface-specific measurement test artefacts designed for use in the verification of AM manufacturing processes are proposed here. Surface-specific test artefacts can be made more compact because they do not require the large dimensions needed for accurate dimensional and form measurements. The series of three test artefacts are designed to provide comprehensive information pertaining to the manufactured surface. Measurement possibilities include deviation analysis, surface texture parameter data generation, sub-surface analysis, layer step analysis and build resolution comparison. The test artefacts are designed to provide easy access for measurement using conventional surface measurement techniques, for example, focus variation microscopy, stylus profilometry, confocal microscopy and scanning electron microscopy. Additionally, the test artefacts may be simply visually inspected as a comparative tool, giving a fast indication of process variation between builds. The three test artefacts are small enough to be included in every build and include built-in manufacturing traceability information, making them a convenient physical record of the build.

Fatigue Performance of Ti-6Al-4V Additively Manufactured Specimens with Integrated Capillaries of an Embedded Structural Health Monitoring System.

Science.gov (United States)

Hinderdael, Michaël; Strantza, Maria; De Baere, Dieter; Devesse, Wim; De Graeve, Iris; Terryn, Herman; Guillaume, Patrick

2017-08-25

Additive manufacturing (AM) of metals offers new possibilities for the production of complex structures. Up to now, investigations on the mechanical response of AM metallic parts show a significant spread and unexpected failures cannot be excluded. In this work, we focus on the detection of fatigue cracks through the integration of a Structural Health Monitoring (SHM) system in Ti-6Al-4V specimens. The working principle of the presented system is based on the integration of small capillaries that are capable of detecting fatigue cracks. Four-point bending fatigue tests have been performed on Ti-6Al-4V specimens with integrated capillaries and compared to the reference specimenswithout capillaries. Specimens were produced by conventional subtractive manufacturing of wrought material and AM, using the laser based Directed Energy Deposition (DED) process. In this study, we investigated the effect of the presence of the capillary on the fatigue strength and fatigue initiation location. Finite element (FEM) simulations were performed to validate the experimental test results. The presence of a drilled capillary in the specimens did not alter the fatigue initiation location. However, the laser based DED production process introduced roughness on the capillary surface that altered the fatigue initiation location to the capillary surface. The fatigue performance was greatly reduced when considering a printed capillary. It is concluded that the surface quality of the integrated capillary is of primary importance in order not to influence the structural integrity of the component to be monitored.

Design of four-point SENB specimens with stable crack growth

DEFF Research Database (Denmark)

Jørgensen, Jeppe Bjørn; Kildegaard, Casper; Sørensen, Bent F.

2018-01-01

A four-point single-edge-notch-beam (SENB) test specimen loaded in displacement control (fixed grip) is proposed for studying crack deflection at bi-material interfaces. In order to ensure stable crack growth, a novel analytical model of the four-point SENB specimen in fixed grip is derived...... and compared with numerical models. Model results show that the specimen should be short and thick, and the start-crack length should be deep for the crack to propagate stable towards the bi-material interface. Observations from experimental tests of four-point SENB specimens with different start-crack lengths...

COMPARISON BETWEEN WOOD DRYING DEFECT SCORES: SPECIMEN TESTING X ANALYSIS OF KILN-DRIED BOARDS

OpenAIRE

Djeison Cesar Batista; Márcio Pereira da Rocha; Ricardo Jorge Klitzke

2015-01-01

It is important to develop drying technologies for Eucalyptus grandis lumber, which is one of the most planted species of this genus in Brazil and plays an important role as raw material for the wood industry. The general aim of this work was to assess the conventional kiln drying of juvenile wood of three clones of Eucalyptus grandis. The specific aims were to compare the behavior between: i) drying defects indicated by tests with wood specimens and conventional kiln-dried boards; and ii) ph...

Roughness and compressive strength of FDM 3D printed specimens affected by acetone vapour treatment

Science.gov (United States)

Beniak, Juraj; Križan, Peter; Šooš, Ľubomír; Matúš, Miloš

2018-01-01

Rapid Prototyping technologies are the fastest growing technologies in the manufacturing of components and parts. There are many techniques which can be used with different materials and different purposes of produced part. Gradually, Rapid Prototyping systems have grown into Additive Manufacturing, because technology expansion brings faster production, improved manufactured components, and expanded palette of used materials. So now this techniques are also used for regular production of special parts, where is usual change of part design, where is necessary to produce variety of different designs and shapes. The following article deals with Fused Deposition Modelling (FDM) technology, the core of which is the manufacture models and components from thermoplastic polymers by deposition single fibres of semi-molten plastic material layer by layer. The article focuses on the results of research for testing of manufactured specimens by FDM technology. Components are modified by acetone vapour for surface smoothing. The purpose is to point out how the additional specimen treatment influence the strength properties. Presented paper shows realized experiments and measurements of compressive force on specimens and surface roughness which are influenced by acetone vapour treatment.

X-ray evaluation of residual stress distributions within surface machined layer generated by surface machining and sequential welding

International Nuclear Information System (INIS)

Taniguchi, Yuu; Okano, Shigetaka; Mochizuki, Masahito

2017-01-01

The excessive tensile residual stress generated by welding after surface machining may be an important factor to cause stress corrosion cracking (SCC) in nuclear power plants. Therefore we need to understand and control the residual stress distribution appropriately. In this study, residual stress distributions within surface machined layer generated by surface machining and sequential welding were evaluated by X-ray diffraction method. Depth directional distributions were also investigated by electrolytic polishing. In addition, to consider the effect of work hardened layer on the residual stress distributions, we also measured full width at half maximum (FWHM) obtained from X-ray diffraction. Testing material was a low-carbon austenitic stainless steel type SUS316L. Test specimens were prepared by surface machining with different cutting conditions. Then, bead-on-plate welding under the same welding condition was carried out on the test specimens with different surface machined layer. As a result, the tensile residual stress generated by surface machining increased with increasing cutting speed and showed nearly uniform distributions on the surface. Furthermore, the tensile residual stress drastically decreased with increasing measurement depth within surface machined layer. Then, the residual stress approached 0 MPa after the compressive value showed. FWHM also decreased drastically with increasing measurement depth and almost constant value from a certain depth, which was almost equal regardless of the machining condition, within surface machined layer in all specimens. After welding, the transverse distribution of the longitudinal residual stress varied in the area apart from the weld center according to machining conditions and had a maximum value in heat affected zone. The magnitude of the maximum residual stress was almost equal regardless of the machining condition and decreased with increasing measurement depth within surface machined layer. Finally, the

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)

Comparison of fracture toughness values from large-scale pipe system tests and C(T) specimens

International Nuclear Information System (INIS)

Olson, R.; Scott, P.; Marschall, C.; Wilkowski, G.

1993-01-01

Within the International Piping Integrity Research Group (IPIRG) program, pipe system experiments involving dynamic loading with intentionally circumferentially cracked pipe were conducted. The pipe system was fabricated from 406-mm (16-inch) diameter Schedule 100 pipe and the experiments were conducted at 15.5 MPa (2,250 psi) and 288 C (550 F). The loads consisted of pressure, dead-weight, thermal expansion, inertia, and dynamic anchor motion. Significant instrumentation was used to allow the material fracture resistance to be calculated from these large-scale experiments. A comparison of the toughness values from the stainless steel base metal pipe experiment of standard quasi-static and dynamic C(T) specimen tests showed the pipe toughness value was significantly lower than that obtained from C(T) specimens. It is hypothesized that the cyclic loading from inertial stresses in this pipe system experiment caused local degradation of the material toughness. Such effects are not considered in current LBB or pipe flaw evaluation criteria. 4 refs., 14 figs., 1 tab

Location specific in situ TEM straining specimens made using FIB

International Nuclear Information System (INIS)

Field, R.D.; Papin, P.A.

2004-01-01

A method has been devised and demonstrated for producing in situ straining specimens for the transmission electron microscope (TEM) from specific locations in a sample using a dual-beam focused ion beam (FIB) instrument. The specimen is removed from a polished surface in the FIB using normal methods and then attached to a pre-fabricated substrate in the form of a modified TEM tensile specimen. In this manner, specific features of the microstructure of a polished optical mount can be selected for in situ tensile straining. With the use of electron backscattered diffraction (EBSD), this technique could be extended to select specific orientations of the specimen as well

Biaxial Creep Specimen Fabrication

Energy Technology Data Exchange (ETDEWEB)

JL Bump; RF Luther

2006-02-09

This report documents the results of the weld development and abbreviated weld qualification efforts performed by Pacific Northwest National Laboratory (PNNL) for refractory metal and superalloy biaxial creep specimens. Biaxial creep specimens were to be assembled, electron beam welded, laser-seal welded, and pressurized at PNNL for both in-pile (JOYO reactor, O-arai, Japan) and out-of-pile creep testing. The objective of this test campaign was to evaluate the creep behavior of primary cladding and structural alloys under consideration for the Prometheus space reactor. PNNL successfully developed electron beam weld parameters for six of these materials prior to the termination of the Naval Reactors program effort to deliver a space reactor for Project Prometheus. These materials were FS-85, ASTAR-811C, T-111, Alloy 617, Haynes 230, and Nirnonic PE16. Early termination of the NR space program precluded the development of laser welding parameters for post-pressurization seal weldments.

Biaxial Creep Specimen Fabrication

International Nuclear Information System (INIS)

JL Bump; RF Luther

2006-01-01

This report documents the results of the weld development and abbreviated weld qualification efforts performed by Pacific Northwest National Laboratory (PNNL) for refractory metal and superalloy biaxial creep specimens. Biaxial creep specimens were to be assembled, electron beam welded, laser-seal welded, and pressurized at PNNL for both in-pile (JOYO reactor, O-arai, Japan) and out-of-pile creep testing. The objective of this test campaign was to evaluate the creep behavior of primary cladding and structural alloys under consideration for the Prometheus space reactor. PNNL successfully developed electron beam weld parameters for six of these materials prior to the termination of the Naval Reactors program effort to deliver a space reactor for Project Prometheus. These materials were FS-85, ASTAR-811C, T-111, Alloy 617, Haynes 230, and Nirnonic PE16. Early termination of the NR space program precluded the development of laser welding parameters for post-pressurization seal weldments

Advantages and disadvantages of technologies for HER2 testing in breast cancer specimens.

Science.gov (United States)

Furrer, Daniela; Sanschagrin, François; Jacob, Simon; Diorio, Caroline

2015-11-01

Human epidermal growth factor receptor 2 (HER2) plays a central role as a prognostic and predictive marker in breast cancer specimens. Reliable HER2 evaluation is central to determine the eligibility of patients with breast cancer to targeted anti-HER2 therapies such as trastuzumab and lapatinib. Presently, several methods exist for the determination of HER2 status at different levels (protein, RNA, and DNA level). In this review, we discuss the main advantages and disadvantages of the techniques developed so far for the evaluation of HER2 status in breast cancer specimens. Each technique has its own advantages and disadvantages. It is therefore not surprising that no consensus has been reached so far on which technique is the best for the determination of HER2 status. Currently, emphasis must be put on standardization of procedures, internal and external quality control assessment, and competency evaluation of already existing methods to ensure accurate, reliable, and clinically meaningful test results. Development of new robust and accurate diagnostic assays should also be encouraged. In addition, large clinical trials are warranted to identify the technique that most reliably predicts a positive response to anti-HER2 drugs. Copyright© by the American Society for Clinical Pathology.

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

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.

Evaluation of impacts of stress triaxiality on plastic deformability of RAFM steel using various types of tensile specimen

Energy Technology Data Exchange (ETDEWEB)

Kato, Taichiro, E-mail: kato.taichiro@jaea.go.jp [Japan Atomic Energy Agency, 2-166, Obuchi-omotedate, Rokkasho, Aomori 039-3212 (Japan); Ohata, Mitsuru [Osaka University, 2-1, Yamada-Oka, Suita, Osaka 565-0871 (Japan); Nogami, Shuhei [Tohoku University, 6-6-01-2, Aramaki-aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Tanigawa, Hiroyasu [Japan Atomic Energy Agency, 2-166, Obuchi-omotedate, Rokkasho, Aomori 039-3212 (Japan)

2016-11-01

Highlights: • The fracture ductility is lower as the stress triaxiality is higher. • Voids of the interrupted RB1 specimen were observed along grain boundaries and expanded parallel to the tensile axis. • Voids of interrupted R0.2 specimen were rounded shape than those of RB1. • The fracture surface of specimens were observed the elongated and the equiaxed dimples. • The decrease of plastic deformability of the notched specimen was caused by the process of voids formation and crack growth due to the effect of plastic constraint of the notch. - Abstract: A case study on a fusion blanket design such as DEMO indicated that there could be some sections with high stress triaxiality, a parameter to evaluate the magnitude of plastic constraint, in the case of plasma disruption or coolant loss accident. Therefore, it is necessary to accurately understand the ductility loss limit of structural material in order to conduct the structural design assessment of the irradiated and embrittled fusion reactor blanket. Tensile tests were conducted by using three kinds of tensile specimen shapes to investigate of the plastic deformability of F82H. From the results, the fracture ductility is lower as the stress triaxiality is higher. Voids of the interrupted RB1 specimen were observed along grain boundaries and expanded parallel to the tensile axis. That of interrupted R0.2 specimen was rounded shape compared with those of RB1. The fracture surface of RB1 and R0.2 specimens were observed the elongated dimples and the equiaxed dimples without so much elongation, respectively. It is considered that the decrease of plastic deformability for the notched specimen was caused by the process of voids formation and crack growth due to the effect of plastic constraint of the notch.

Influence of ceramic surface texture on the wear of gold alloy and heat-pressed ceramics.

Science.gov (United States)

Saiki, Osamu; Koizumi, Hiroyasu; Nogawa, Hiroshi; Hiraba, Haruto; Akazawa, Nobutaka; Matsumura, Hideo

2014-01-01

The purpose of this study was to evaluate the influence of ceramic surface texture on the wear of rounded rod specimens. Plate specimens were fabricated from zirconia (ZrO2), feldspathic porcelain, and lithium disilicate glass ceramics (LDG ceramics). Plate surfaces were either ground or polished. Rounded rod specimens with a 2.0-mm-diameter were fabricated from type 4 gold alloy and heat-pressed ceramics (HP ceramics). Wear testing was performed by means of a wear testing apparatus under 5,000 reciprocal strokes of the rod specimen with 5.9 N vertical loading. The results were statistically analyzed with a non-parametric procedure. The gold alloy showed the maximal height loss (90.0 µm) when the rod specimen was abraded with ground porcelain, whereas the HP ceramics exhibited maximal height loss (49.8 µm) when the rod specimen was abraded with ground zirconia. There was a strong correlation between height loss of the rod and surface roughness of the underlying plates, for both the gold alloy and HP ceramics.

Analysis of the Mechanical Behavior and Surface Rugosity of Different Dental Die Materials.

Science.gov (United States)

Niekawa, Ciro T; Kreve, Simone; A'vila, Gisseli Bertozzi; Godoy, Gilmar Gil; Eduardo Vieira da Silva, J R; Dias, Sergio Candido

2017-01-01

This work evaluated the mechanical and surface behavior of different die materials. The studied materials are polyurethane resin Exakto-Form (Bredent), Gypsum type IV, Fuji Rock EP (Gc), and Durone (Dentsply). Two metallic matrices molded in polyvinyl siloxane provided 30 cylindrical test specimens for the diametral compression test and 30 hemispherical test specimens for the surface rugosity test. The cylindrical test specimens were submitted to tests of diametral compression strength using a DL2000 universal assay machine, with a load cell of 2000 Kgf and constant speed of 1 mm/min connected to the software. Kruskal-Wallis and Dunn's nonparametric tests were used to analyze the results. The hemispheres were submitted to the surface rugosity assay using a SJ201-P rugosimeter with a sensitivity of 300 μm, speed of 0.5 mm/s, and cut-off of 0.8 mm, and the readings were taken on the convex surface of the test specimens and metallic matrix. Results were analyzed using with Fisher's least significant differences test (LSD) and Dunnett's test. Kruskal-Wallis test showed significant difference between die materials for diametral compression strength ( P = 0.002). Dunn's test showed significantly higher values for modified polyurethane resin (Exakto-Form). The gypsum type IV, which did not significantly differ regarding diametral compression strength, showed 34.0% (Durone) and 42.7% (Fuji Rock) lower values in comparison to Exakto-Form. Within the parameters adopted in this study, it is possible to conclude that Exakto-Form polyurethane resin showed higher resistance to compression and was closer to the metallic matrix rugosity, and, along with the gypsum type IV Durone, showed better reproducibility of details relative to the Fuji Rock.

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.

Laser-driven planar impact of miniature specimens of HY-100 steel

International Nuclear Information System (INIS)

Alexander, David J.; Robbins, David L.

2002-01-01

The deformation and fracture behavior of HY-100, a high-strength steel, under high strain-rate planar-impact conditions, has been studied with the Laser-Driven Miniflyer apparatus. Cold-rolled copper flyers 3 mm in diameter and either 50 or 100 microns thick have been laser-launched against HY-100 targets, 200 microns thick and nominally 10 mm square. The target specimens were sectioned from the 25-mm-thick HY-100 plate in three mutually perpendicular orientations, either parallel or perpendicular to the plate rolling direction. The back-surface response of the HY-100 targets was monitored with dual VISARs. The flyer velocity was varied to produce a range of behavior, from deformation at low velocities, to damage formation at intermediate velocities, and finally to complete spall failure at the highest velocities. The target specimens were sectioned after testing to examine the microstructure and failure processes of the deformed material. Spall strengths were calculated from the VISAR signals. The VISAR traces showed well-defined elastic precursors, which were similar for all orientations of the specimens. The spall strengths, as estimated from the magnitude of the pullback signal, were also similar for all three orientations. The spall strength increased as the flyer impact velocity increased, to values of about 4.6 GPa. Metallographic examination revealed that damage occurred at lower impact velocities in specimens loaded in the through-thickness direction of the plate, as compared to specimens oriented parallel to the plate thickness, but this difference was not reflected in the pull-back signal or the spall strengths

Friction behavior and other material properties of nickel-titanium and titanium-molybdenum archwires following electrochemical surface refinement.

Science.gov (United States)

Meier, Miriam Julia; Bourauel, Christoph; Roehlike, Jan; Reimann, Susanne; Keilig, Ludger; Braumann, Bert

2014-07-01

The aim of this work was to investigate whether electrochemical surface treatment of nickel-titanium (NiTi) and titanium-molybdenum (TiMo) archwires (OptoTherm and BetaTitan; Ortho-Dent Specials, Kisdorf, Germany) reduces friction inside the bracket-archwire complex. We also evaluated further material properties and compared these to untreated wires. The material properties of the surface-treated wires (Optotherm/LoFrix and BetaTitan/LoFrix) were compared to untreated wires made by the same manufacturer (see above) and by another manufacturer (Neo Sentalloy; GAC, Bohemia, NY, USA). We carried out a three-point bending test, leveling test, and friction test using an orthodontic measurement and simulation system (OMSS). In addition, a pure bending test was conducted at a special test station, and scanning electron micrographs were obtained to analyze the various wire types for surface characteristics. Finally, edge beveling and cross-sectional dimensions were assessed. Force losses due to friction were reduced by 10 percentage points (from 36 to 26%) in the NiTi and by 12 percentage points (from 59 to 47%) in the TiMo wire specimens. Most of the other material properties exhibited no significant changes after surface treatment. While the three-point bending tests revealed mildly reduced force levels in the TiMo specimens due to diameter losses of roughly 2%, these force levels remained almost unchanged in the NiTi specimens. Compared to untreated NiTi and TiMo archwire specimens, the surface-treated specimens demonstrated reductions in friction loss by 10 and 12 percentage points, respectively.

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.

Void coalescence and fracture behavior of notched and un-notched tensile tested specimens in fine grain dual phase steel

Energy Technology Data Exchange (ETDEWEB)

Saeidi, N., E-mail: navidsae@gmail.com [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Ashrafizadeh, F.; Niroumand, B. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Forouzan, M.R.; Mohseni mofidi, S. [Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Barlat, F. [Materials Mechanics Laboratory (MML), Graduate Institute of Ferrous Technology (GIFT), Pohang University of Science and Technology POSTECH, San 31 Hyoja-dong, Nam-gu, Pohang, Gyeongbuk 790-784 (Korea, Republic of)

2015-09-17

Due to growing global concern about the environmental issues, steel developers have been forced by automobile makers to produce more efficient steel grades with high strength to weight ratios along with high crashworthiness performance. In order to find deficiencies of the existing steels and develop superior steel products, detailed understanding of deformation and damage behavior in the existing steels is needed. In the present research, deformation and damage evolution during room temperature uniaxial tensile test of a modern high strength Dual Phase Steel, i.e. DP780, were studied. Detailed scanning electron microscopy (SEM) examination of the microstructures of notched and un-notched tensile fractured specimens revealed that in notched specimen, plastic deformation was concentrated more within the notched region. Therefore, much higher reduction in thickness with a high reduction gradient occurred in this region, In the un-notched specimen, however, plastic deformation was more uniformly distributed in larger parts of the gauge length, and therefore, thickness reduction happened with a lower gradient. Although geometric notch on the specimen did not change the void nucleation and growth mechanisms, the kinetics of these phenomena was influenced. On the other hand, voids linkage mechanism tended to change from void coalescence in the un-notched specimen to void sheeting in the notched specimen. Moreover, three different models developed by Brown & Embury (BM), Thomason and Pardoen were employed to predict the final fracture strain. It was revealed that, BM model showed much more accurate predictions for the studied DP steel in comparison with those of Thomason and Pardoens’ models.

Void coalescence and fracture behavior of notched and un-notched tensile tested specimens in fine grain dual phase steel

International Nuclear Information System (INIS)

Saeidi, N.; Ashrafizadeh, F.; Niroumand, B.; Forouzan, M.R.; Mohseni mofidi, S.; Barlat, F.

2015-01-01

Due to growing global concern about the environmental issues, steel developers have been forced by automobile makers to produce more efficient steel grades with high strength to weight ratios along with high crashworthiness performance. In order to find deficiencies of the existing steels and develop superior steel products, detailed understanding of deformation and damage behavior in the existing steels is needed. In the present research, deformation and damage evolution during room temperature uniaxial tensile test of a modern high strength Dual Phase Steel, i.e. DP780, were studied. Detailed scanning electron microscopy (SEM) examination of the microstructures of notched and un-notched tensile fractured specimens revealed that in notched specimen, plastic deformation was concentrated more within the notched region. Therefore, much higher reduction in thickness with a high reduction gradient occurred in this region, In the un-notched specimen, however, plastic deformation was more uniformly distributed in larger parts of the gauge length, and therefore, thickness reduction happened with a lower gradient. Although geometric notch on the specimen did not change the void nucleation and growth mechanisms, the kinetics of these phenomena was influenced. On the other hand, voids linkage mechanism tended to change from void coalescence in the un-notched specimen to void sheeting in the notched specimen. Moreover, three different models developed by Brown & Embury (BM), Thomason and Pardoen were employed to predict the final fracture strain. It was revealed that, BM model showed much more accurate predictions for the studied DP steel in comparison with those of Thomason and Pardoens’ models

Crack Propagation on ESE(T) Specimens Strengthened with CFRP Sheets

DEFF Research Database (Denmark)

Hansen, Christian Skodborg; Jensen, Peter Holmstrøm; Dyrelund, Jens

2009-01-01

In this paper fatigue tests on side notched steel test specimens strengthened with adhesive bonded fibre reinforced polymer (FRP) sheets are presented. The specimens are subject to crack growth both in the steel and bond line. Influence of the load ratio and initial crack length on the overall...

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)

Nondestructive detection of surface flaws in materials by infrared thermography

International Nuclear Information System (INIS)

Ishii, Toshimitsu; Ooka, Norikazu; Eto, Motokuni; Hoshiya, Taiji; Okamoto, Yoshizo

1999-01-01

Infrared thermography is one of the useful remote sensing techniques applied to the nondestructive detection of surface flaws in materials. Radiation temperatures of the specimen surface and surrounding walls as well as the difference in them are crucial factors to detect surface flaws from thermal images, and it is essential that these factors be properly evaluated beforehand in order to detect the flaws by infrared thermography. In this study, the radiation temperature of nuclear graphite specimens heated uniformly was measured by infrared thermography to evaluate the radiation characteristics such as emissivity, radiosity coefficient and variation of radiation temperature. The influence of the temperature difference between the test specimen and its surroundings on the limit of detection of pinhole flaws was discussed on the basis of the thermal images of graphite specimen with surface flaws. It was found that the thermal image of a small flaw was clearly visible with increase in the temperature difference. (author)

Evaluation of the protection behaviour of reinforcement steel against corrosion induced by chlorides in reinforced mortar specimens

International Nuclear Information System (INIS)

Crivelaro, Marcos

2002-01-01

In this work various treatments for protecting reinforcing steels against corrosion induced by chlorides have been evaluated. Additives to mortars and surface treatments given to reinforcing steels were evaluated as corrosion protection measures. In the preliminary tests the corrosion resistance of a CA 50 steel treated by immersion in nearly 50 different solutions, was determined. The solutions were prepared with tannins (from various sources) and/or benzotriazole, and during immersion, a surface film formed on the steel. The corrosion resistance of the coated steels was evaluated in a saturated Ca(OH) 2 solution with 5% (wt) NaCl. Preliminary tests were also carried out with mortars reinforced with uncoated steel to which tannin or lignin was added. Two organic coatings, a monocomponent and a bicomponent type, formulated specially for this investigation, with both tannin and benzotriazole, were also tested in the preliminary tests to select the coating with better corrosion protection property. The bicomponent type (epoxy coating) showed better performance than the monocomponent type coating, and the former was therefore chosen to investigate the corrosion performance on CA 50 steel inside mortar specimens. From the preliminary tests, two solutions with tannin from two sources, Black Wattle (Acacia mearnsii) and Brazilian tea (Ilex paraguariensis St. Hill), to which benzotriazole and phosphoric acid were added, were chosen. Mortar specimens reinforced with CA50 steel treated by immersion in these two solutions were prepared. Also, epoxy coated CA50 steel was tested as reinforcement inside mortar specimens. Mortars reinforced with uncoated CA50 steel were also prepared and corrosion tested for comparison. The effect of tannin and lignin as separate additives to the mortar on the corrosion resistance of uncoated steel was also studied. The reinforced mortar specimens were tested with various cycles of immersion for 2 days in 3.5% (wt) NaCl followed by with air

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.

Detection of adenovirus in nasopharyngeal specimens by radioactive and nonradioactive DNA probes

International Nuclear Information System (INIS)

Hyypiae, T.

1985-01-01

The presence of adenovirus DNA in clinical specimens was analyzed by nucleic acid hybridization assays by both radioactive and enzymatic detection systems. The sensitivity of the hybridization tests was in the range of 10 to 100 pg of homologous adenovirus DNA. Minimal background was noticed with unrelated viral and nonviral DNA. Twenty-four nasopharyngeal mucus aspirate specimens, collected from children with acute respiratory infection, were assayed in the hybridization tests and also by an enzyme immunoassay for adenovirus hexon antigen which was used as a reference test. Sixteen specimens positive by the enzyme immunoassay also were positive in the two nucleic acid hybridization tests, and the remaining eight specimens were negative in all of the tests. The results indicate that nucleid acid hybridization tests with both radioactive and nonradioactive probes can be used for diagnosis of microbial infections

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).

Influence of Pre-Sintered Zirconia Surface Conditioning on Shear Bond Strength to Resin Cement

Directory of Open Access Journals (Sweden)

Tomofumi Sawada

2016-06-01

Full Text Available This study analyzed the shear bond strength (SBS of resin composite on zirconia surface to which a specific conditioner was applied before sintering. After sintering of either conditioner-coated or uncoated specimens, both groups were divided into three subgroups by their respective surface modifications (n = 10 per group: no further treatment; etched with hydrofluoric acid; and sandblasted with 50 µm Al2O3 particles. Surfaces were characterized by measuring different surface roughness parameters (e.g., Ra and Rmax and water contact angles. Half of the specimens underwent thermocycling (10,000 cycles, 5–55 °C after self-adhesive resin cement build-up. The SBSs were measured using a universal testing machine, and the failure modes were analyzed by microscopy. Data were analyzed by nonparametric and parametric tests followed by post-hoc comparisons (α = 0.05. Conditioner-coated specimens increased both surface roughness and hydrophilicity (p < 0.01. In the non-thermocycled condition, sandblasted surfaces showed higher SBSs than other modifications, irrespective of conditioner application (p < 0.05. Adhesive fractures were commonly observed in the specimens. Thermocycling favored debonding and decreased SBSs. However, conditioner-coated specimens upon sandblasting showed the highest SBS (p < 0.05 and mixed fractures were partially observed. The combination of conditioner application before sintering and sandblasting after sintering showed the highest shear bond strength and indicated improvements concerning the failure mode.

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)

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)

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

Surface Model and Tomographic Archive of Fossil Primate and Other Mammal Holotype and Paratype Specimens of the Ditsong National Museum of Natural History, Pretoria, South Africa.

Directory of Open Access Journals (Sweden)

Justin W Adams

Full Text Available Nearly a century of paleontological excavation and analysis from the cave deposits of the Cradle of Humankind UNESCO World Heritage Site in northeastern South Africa underlies much of our understanding of the evolutionary history of hominins, other primates and other mammal lineages in the late Pliocene and early Pleistocene of Africa. As one of few designated fossil repositories, the Plio-Pleistocene Palaeontology Section of the Ditsong National Museum of Natural History (DNMNH; the former Transvaal Museum curates much of the mammalian faunas recovered from the fossil-rich deposits of major South African hominin-bearing localities, including the holotype and paratype specimens of many primate, carnivore, and other mammal species (Orders Primates, Carnivora, Artiodactyla, Eulipotyphla, Hyracoidea, Lagomorpha, Perissodactyla, and Proboscidea. Here we describe an open-access digital archive of high-resolution, full-color three-dimensional (3D surface meshes of all 89 non-hominin holotype, paratype and significant mammalian specimens curated in the Plio-Pleistocene Section vault. Surface meshes were generated using a commercial surface scanner (Artec Spider, Artec Group, Luxembourg, are provided in formats that can be opened in both open-source and commercial software, and can be readily downloaded either via an online data repository (MorphoSource or via direct request from the DNMNH. In addition to providing surface meshes for each specimen, we also provide tomographic data (both computerized tomography [CT] and microfocus [microCT] for a subset of these fossil specimens. This archive of the DNMNH Plio-Pleistocene collections represents the first research-quality 3D datasets of African mammal fossils to be made openly available. This simultaneously provides the paleontological community with essential baseline information (e.g., updated listing and 3D record of specimens in their current state of preservation and serves as a single resource of

Surface Model and Tomographic Archive of Fossil Primate and Other Mammal Holotype and Paratype Specimens of the Ditsong National Museum of Natural History, Pretoria, South Africa.

Science.gov (United States)

Adams, Justin W; Olah, Angela; McCurry, Matthew R; Potze, Stephany

2015-01-01

Nearly a century of paleontological excavation and analysis from the cave deposits of the Cradle of Humankind UNESCO World Heritage Site in northeastern South Africa underlies much of our understanding of the evolutionary history of hominins, other primates and other mammal lineages in the late Pliocene and early Pleistocene of Africa. As one of few designated fossil repositories, the Plio-Pleistocene Palaeontology Section of the Ditsong National Museum of Natural History (DNMNH; the former Transvaal Museum) curates much of the mammalian faunas recovered from the fossil-rich deposits of major South African hominin-bearing localities, including the holotype and paratype specimens of many primate, carnivore, and other mammal species (Orders Primates, Carnivora, Artiodactyla, Eulipotyphla, Hyracoidea, Lagomorpha, Perissodactyla, and Proboscidea). Here we describe an open-access digital archive of high-resolution, full-color three-dimensional (3D) surface meshes of all 89 non-hominin holotype, paratype and significant mammalian specimens curated in the Plio-Pleistocene Section vault. Surface meshes were generated using a commercial surface scanner (Artec Spider, Artec Group, Luxembourg), are provided in formats that can be opened in both open-source and commercial software, and can be readily downloaded either via an online data repository (MorphoSource) or via direct request from the DNMNH. In addition to providing surface meshes for each specimen, we also provide tomographic data (both computerized tomography [CT] and microfocus [microCT]) for a subset of these fossil specimens. This archive of the DNMNH Plio-Pleistocene collections represents the first research-quality 3D datasets of African mammal fossils to be made openly available. This simultaneously provides the paleontological community with essential baseline information (e.g., updated listing and 3D record of specimens in their current state of preservation) and serves as a single resource of high

Linear Array Ultrasonic Test Results from Alkali-Silica Reaction (ASR) Specimens

Energy Technology Data Exchange (ETDEWEB)

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

2016-04-01

The purpose of the U.S. Department of Energy Office of Nuclear Energy’s Light Water Reactor Sustainability (LWRS) Program is to develop technologies and other solutions that can improve the reliability, sustain the safety, and extend the operating lifetimes of nuclear power plants (NPPs) beyond 60 years. Since many important safety structures in an NPP are constructed of concrete, inspection techniques must be developed and tested to evaluate the internal condition. In-service containment structures generally do not allow for the destructive measures necessary to validate the accuracy of these inspection techniques. This creates a need for comparative testing of the various nondestructive evaluation (NDE) measurement techniques on concrete specimens with known material properties, voids, internal microstructure flaws, and reinforcement locations.This report presents results of the ultrasound evaluation of four concrete slabs with varying levels of ASR damage present. This included an investigation of the experimental results, as well as a supplemental simulation considering the effect of ASR damage by elasto-dynamic wave propagation using a finite integration technique method. It was found that the Hilbert Transform Indicator (HTI), developed for quantification of freeze/thaw damage in concrete structures, could also be successfully utilized for quantification of ASR damage. internal microstructure flaws, and reinforcement locations.

[Wear intensity and surface roughness of microhybrid composite and ceramic occlusal veneers on premolars after the thermocycling and cyclic mechanical loading tests].

Science.gov (United States)

Zhang, H Y; Jiang, T; Cheng, M X; Zhang, Y W

2018-02-18

To evaluate the wear intensity and surface roughness of occlusal veneers on premolars made of microhybrid composite resin or two kinds of ceramics in vitro after the thermocycling and cyclic mechanical loading tests. In the study,24 fresh extracted human premolars without root canal treatment were prepared (cusps reduction of 1.5 mm in thickness to simulate middle to severe tooth wear, the inclinations of cusps were 20°). The prepared teeth were restored with occlusal veneers made of three different materials: microhybrid composite, heat-pressed lithium disilicate ceramic and computer-aided design/computer-aided manufacturing (CAD/CAM) lithium disilicate ceramic in the thickness of 1.5 mm. The occlusal veneers were cemented with resin cement. The specimens were fatigued using the thermocycling and cyclic mechanical loading tests after being stored in water for 72 h. The wear of specimens was measured using gypsum replicas and 3D laser scanner before and after the thermocycling and cyclic mechanical loading tests and the mean lost distance (mm) was used to indicate the level of wear. The surfaces of occlusal contact area were observed and the surface roughness was recorded using 3D laser scanning confocal microscope before and after the fatigue test. Differences between the groups were compared using ONE-way ANOVA(Pcomposite group, heat-pressed lithium disilicate ceramic group, and CAD/CAM lithium disilicate ceramic group was (-0.13±0.03) mm, (-0.05±0.01) mm and (-0.05±0.01) mm, the wear of microhybrid composite was significantly higher than the two ceramic groups(Pcomposite was significantly higher than the two ceramic groups(Pcomposite(P=0.005) and CAD/CAM lithium disilicate ceramic (P=0.010). From the view of wear speed, microhybrid composite was significantly higher than the two kinds of ceramics, but it was similar to enamel when the opposing tooth was natural. The surface roughness before the themocycling and cyclic mechanical loading test of microhybrid

Illustration of the WPS benefit through BATMAN test series: Tests on large specimens under WPS loading configurations

International Nuclear Information System (INIS)

Yuritzinn, T.; Ferry, L.; Chapuliot, S.; Mongabure, P.; Moinereau, D.; Dahl, A.; Gilles, P.

2008-01-01

To study the effects of warm pre-stressing on the toughness of reactor pressure vessel steel, the 'Commissariat a l Energie Atomique', in collaboration with 'Electricite de France' and AREVA-NP, has made a study combining modeling and a series of experiments on large specimens submitted to a thermal shock or isothermal cooling. The tests were made on 18MND5 ferritic steel bars, containing a short or large fatigue pre-crack. The effect of 'warm pre-stressing' was confirmed, in the two cases of a fast thermal shock creating a gradient across the thickness of the bar and for gradual uniform cooling. In both cases, no propagation was observed during the thermal transient. Fracture occurred under low temperature conditions, at the end of the test when the tensile load was increased. The failure loads recorded were substantially higher than during pre-stressing. To illustrate the benefit of the WPS effect, numerical interpretations were performed using either global approach or local approach criteria. WPS effect and capability of models to predict it were then clearly shown. (authors)

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

Specimen aspect ratio and progressive field strain development of sandstone under uniaxial compression by three-dimensional digital image correlation

Directory of Open Access Journals (Sweden)

H. Munoz

2017-08-01

Full Text Available The complete stress–strain characteristics of sandstone specimens were investigated in a series of quasi-static monotonic uniaxial compression tests. Strain patterns development during pre- and post-peak behaviours in specimens with different aspect ratios was also examined. Peak stress, post-peak portion of stress–strain, brittleness, characteristics of progressive localisation and field strain patterns development were affected at different extents by specimen aspect ratio. Strain patterns of the rocks were obtained by applying three-dimensional (3D digital image correlation (DIC technique. Unlike conventional strain measurement using strain gauges attached to specimen, 3D DIC allowed not only measuring large strains, but more importantly, mapping the development of field strain throughout the compression test, i.e. in pre- and post-peak regimes. Field strain development in the surface of rock specimen suggests that strain starts localising progressively and develops at a lower rate in pre-peak regime. However, in post-peak regime, strains increase at different rates as local deformations take place at different extents in the vicinity and outside the localised zone. The extent of localised strains together with the rate of strain localisation is associated with the increase in rate of strength degradation. Strain localisation and local inelastic unloading outside the localised zone both feature post-peak regime.

Ultrasonic testing technique for users in practical application. Pt. 8

International Nuclear Information System (INIS)

Corsepius, H.W.

1978-01-01

In the present, eighth part of ultrasonic testing technique for users in practical application, the two methods 1) testing by gap coupling and 2) testing by the dipping technique are treated. By the first method the probe is clamped in a holding device in such manner that a water-filled gap remains between probe and surface. Through this gap the sonic signal gets into the specimen without mechanical contact between probe and specimen taking place. By the dipping technique testing is performed in a tank filled with water, the probe being guided over the specimen under water. (RW) [de

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.

Detection of cervical precancerous lesions with Aptima HPV assays using SurePath preservative fluid specimens

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Max Chernesky

2017-06-01

Full Text Available SurePath specimens from women referred to colposcopy were treated with Aptima Transfer Solution (ATS before testing in Aptima HPV (AHPV and Aptima HPV 16, 18/45 (AHPV-GT assays. Untreated SurePath specimens were tested with the cobas HPV test. PreservCyt specimens were assessed for cytology and tested with AHPV. High-grade cervical intraepithelial neoplasia lesions served as the reference standard. Excellent agreement (95.5%; k=0.91 was observed for ATS-treated SurePath specimens between Tigris and Panther systems and between the PreservCyt and ATS-treated SurePath specimens (91.1%, k=0.81 with the AHPV assay on Tigris. Agreement between the AHPV and cobas assays with SurePath specimens was substantial (89.9%, k=0.80. AHPV sensitivity for CIN2+(n=147 was 91.2% for SurePath and PreservCyt. Cobas HPV sensitivity was 93.9% for SurePath specimens. AHPV testing of SurePath specimens was more specific (59.4% than cobas (54.7% (p<0.001. Detection and genotyping showed similar absolute and relative risks. ATS-treated SurePath specimens tested with AHPV and AHPV-GT assays showed similar performance with greater specificity than cobas HPV on SurePath specimens. Similar overall results were seen using a CIN3 disease endpoint. Keywords: Human papillomavirus, SurePath, PreservCyt, Cervical intraepithelial neoplasia, CIN2+, Aptima transfer solution (ATS

Scanning Electron Microscope Mapping System Developed for Detecting Surface Defects in Fatigue Specimens

Science.gov (United States)

Bonacuse, Peter J.; Kantzos, Peter T.

2002-01-01

An automated two-degree-of-freedom specimen positioning stage has been developed at the NASA Glenn Research Center to map and monitor defects in fatigue specimens. This system expedites the examination of the entire gauge section of fatigue specimens so that defects can be found using scanning electron microscopy (SEM). Translation and rotation stages are driven by microprocessor-based controllers that are, in turn, interfaced to a computer running custom-designed software. This system is currently being used to find and record the location of ceramic inclusions in powder metallurgy materials. The mapped inclusions are periodically examined during interrupted fatigue experiments. The number of cycles to initiate cracks from these inclusions and the rate of growth of initiated cracks can then be quantified. This information is necessary to quantify the effect of this type of defect on the durability of powder metallurgy materials. This system was developed with support of the Ultra Safe program.

Improvement of Surface Properties of CP-Titanium by Thermo-Chemical Treatment (TCT) Process

International Nuclear Information System (INIS)

Jeong, Hyeon-Gyeong; Hur, Bo-Young; Lee, Dong-Geun; Lee, Yong-Tai; Yaskiv, O.

2011-01-01

The thermo-chemical treatment (TCT) process was applied to achieve surface hardening of CP titanium. The following three different surface modification conditions were tested so that the best surface hardening process could be selected:(a) PVD, (b) TCT+PVD, and (c) TCT+Aging+PVD. These specimens were tested and analyzed in terms of surface roughness, wear, friction coefficient, and the gradient of hardening from the surface of the matrix. The three test conditions were all beneficial to improve the surface hardness of CP titanium. Moreover, the TCT treated specimens, that is, (b) and (c), showed significantly improved surface hardness and low friction coefficients through the thickness up to 100um. This is due to the functionally gradient hardened surface improvement by the diffused interstitial elements. The hardened surface also showed improvement in bonding between the PVD and TCT surface, and this leads to improvement in wear resistance. However, TCT after aging treatment did not show much improvement in surface properties compared to TCT only. For the best surface hardening on CP titanium, TCT+PVD has advantages in surface durability and economics.

Evaluating empirical/analytical techniques to predict structural integrity of pipe containing surface flaws

International Nuclear Information System (INIS)

Reuter, W.G.; Server, W.L.

1982-01-01

Data from flat-plate specimens containing either triangular-, ellipsoidal- or rectangular-shaped surface flaws were evaluated by several potential analytical techniques. These techniques were modified as needed to predict conditions for initiation of subcritical crack growth, for the defect to penetrate the 6.4 mm (0.25 in.) wall thickness, and for instability (plastic or unstable). The modified analytical techniques developed from the plate specimens were then used to make predictions which are compared with test results obtained from pipe specimens containing triangular-shaped surface flaws

Microwave radiation is effective at disinfecting dental stone surfaces without changing their physical properties.

Science.gov (United States)

Bona, Ariel José; Amaral-Brito, Mauro Gustavo; Rodrigues, José Augusto; Peruzzo, Daiane Cristina; França, Fabiana Mantovani Gomes

2017-01-01

The aims of this study were to evaluate the effectiveness of different microwave radiation regimens for disinfection of type IV dental stone surfaces and to assess the influence of these regimens on surface roughness and dimensional change following disinfection. Three hundred cylindrical (20 × 2-mm) test specimens were made in type IV stone and divided into subgroups of 20 according to the microorganisms tested (Staphylococcus aureus, Escherichia coli, or Candida albicans) and the 900-W microwave radiation protocol (cycles of 3, 5, or 7 minutes; a positive control; or a negative control). To test physical changes, 80 test specimens were made with the same dimensions except that they had 2 parallel and symmetrical indentations measuring 8 × 4 mm. These specimens were divided into 4 subgroups of 20 each (a subgroup for each radiation time and a negative control). The mean dimensional change and roughness data were analyzed by mixed models for repeated measures and Tukey-Kramer tests. Disinfection was analyzed with descriptive statistics. For E coli and C albicans, all radiation times proved effective at sterilizing the test specimens. For S aureus, sterilization was achieved with 5 and 7 minutes of exposure; however, colonies were observed in 10 Petri dishes (50%) exposed to 3 minutes of microwave radiation. No statistically significant difference in dimensional change or surface roughness was observed for any radiation regimen (P > 0.05).

Prediction of multiaxial fatigue life for notched specimens of titanium alloy TC4

Energy Technology Data Exchange (ETDEWEB)

Wu, Z. R.; Li, Z. X. [Southeast University, Nanjing (China); Hu, X. T.; Song, Y. D. [Nanjing University, Nanjing (China)

2016-05-15

Both the proportional and nonproportional multiaxial fatigue tests were conducted on two kinds of notched specimens of titanium alloy TC4. The multiaxial fatigue critical area of notched specimen is considered as the location experiencing the maximum damage. It is unsatisfactory to predict the multiaxial fatigue life with the local stress and strain in the fatigue critical area. The critical distance concepts are employed in the multiaxial life prediction method for notched specimens. The proposed method was checked by the test data of TC4 notched specimens. The prediction results are almost within a factor of three scatter band of the test results.

Patient safety in the clinical laboratory: a longitudinal analysis of specimen identification errors.

Science.gov (United States)

Wagar, Elizabeth A; Tamashiro, Lorraine; Yasin, Bushra; Hilborne, Lee; Bruckner, David A

2006-11-01

Patient safety is an increasingly visible and important mission for clinical laboratories. Attention to improving processes related to patient identification and specimen labeling is being paid by accreditation and regulatory organizations because errors in these areas that jeopardize patient safety are common and avoidable through improvement in the total testing process. To assess patient identification and specimen labeling improvement after multiple implementation projects using longitudinal statistical tools. Specimen errors were categorized by a multidisciplinary health care team. Patient identification errors were grouped into 3 categories: (1) specimen/requisition mismatch, (2) unlabeled specimens, and (3) mislabeled specimens. Specimens with these types of identification errors were compared preimplementation and postimplementation for 3 patient safety projects: (1) reorganization of phlebotomy (4 months); (2) introduction of an electronic event reporting system (10 months); and (3) activation of an automated processing system (14 months) for a 24-month period, using trend analysis and Student t test statistics. Of 16,632 total specimen errors, mislabeled specimens, requisition mismatches, and unlabeled specimens represented 1.0%, 6.3%, and 4.6% of errors, respectively. Student t test showed a significant decrease in the most serious error, mislabeled specimens (P patient safety projects. Trend analysis demonstrated decreases in all 3 error types for 26 months. Applying performance-improvement strategies that focus longitudinally on specimen labeling errors can significantly reduce errors, therefore improving patient safety. This is an important area in which laboratory professionals, working in interdisciplinary teams, can improve safety and outcomes of care.

Horizontal loading test by whole model specimen simulating inner concrete structure of PWR type nuclear power plant

International Nuclear Information System (INIS)

Furuya, Noriyuki; Sekine, Masataka; Kimura, Kozo; Yamaguchi, Yoshihiro; Yamaguchi, Tsuneo; Takeda, Toshikazu

1985-01-01

The Nuclear Power Engineering Test Center has performed a horizontal loading test by a whole model specimen simulating the inner concrete structure of a PWR type nuclear power plant in order to investigate restoring force characteristics of reactor buildings. This report describes the results of examination of applicability to the test results of analysis methods based on elastic theory. The analysis results of elastic stiffness, concrete cracking load, rebar yielding loads and ultimate strength were compared with the test results. According to this examination, it is recognized that even these analysis methods based on elastic theory are comparatively effective for analysis of an inner concrete structure of fairly complex configuration, although there are limits of the scope of applicability. (author)

Detection of defects and evaluation of material deterioration using surface wave technique

International Nuclear Information System (INIS)

Yokono, Yoshikazu; Yoshiara, Toshikatsu; Suetsugu, Jun; Imanaka, Takuichi

1996-01-01

It is very important to detect surface damage and evaluate deterioration of material surface because of their influences on mechanical properties of materials. In general, magnetic particle testing, liquid penetrant testing and eddy current testing are commonly used for detecting surface flaws. These methods, however, are neither effective for estimating flaw height nor for evaluating material deterioration. In this paper the authors apply surface wave propagating along the test surface for these purposes. The surface wave (Rayleigh wave) propagates only near the surface layer in the order of one wave length. In other words, the lower the frequency, the deeper the penetration depth of the surface wave. Accordingly, they can select the frequency considering the inspection purpose. On the other hand, when surface wave having broad-band frequency propagates along the surface of a specimen, higher frequency ultrasound propagates very close to the surface and lower frequency ultrasound propagates deeper in the specimen. Hence, frequency analysis is expected to be effective for estimating upper edge of flaw. Surface wave is also very sensitive to material surface properties such as existence of voids or micro cracks. Acoustic characteristics such as sound velocity, attenuation and other feature parameters are influenced by the variation of the material properties. Hence, material deterioration can be evaluated by the acoustic features

Effect of copper, tin, phosphorous and arsenic on the surface cracking of a 18-8 stainless steel during hot compression tests

International Nuclear Information System (INIS)

Botella, J.; Fernandez, M.T.; Fernandez de Castillo, I.

1998-01-01

The effect of certain different concentrations of Cu, Sn, P and As on the surface cracking of 18-8 austenitic stainless steel hot compressed specimens has been studied, at 1,123 and 1,273 K, in an oxidizing atmosphere (air). A procedure for determining surface cracking has been established, and the cracking factor obtained in this ways is correlated with the chemical composition of the materials at both temperatures. The cracking factors obtained at 1,273 K have been compared with the reduction of area drops obtained by hot tension tests at the same temperature. (Author) 5 refs

A Study on Mechanical behavior of Tensile Specimen Fabricated by Laser Cutting

Energy Technology Data Exchange (ETDEWEB)

Jin, Y. G.; Kim, G. S.; Baik, S. J.; Baek, S. Y. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

The mechanical testing data are required for the assessment of dry storage of the spent nuclear fuel. Laser cutting system could be useful tools for material processing such as cutting in radioactive environment due to non-contact nature, ease in handling and the laser cutting process is most advantageous, offering the narrow kerf width and heat affected zone by using small beam spot diameter. The feasibility of the laser cutting system was demonstrated for the fabrication of various types of the unirradiated cladding with and without oxide layer on the specimens. In the present study, the dimensional measurement and tensile test were conducted to investigate the mechanical behavior of the axial tensile test specimens depending on the material processing methods in a hot cell at IMEF (Irradiated Materials Examination Facility) of KAERI. Laser cutting system was used to fabricate the tensile test specimens, and the mechanical behavior was investigated using the dimensional measurement and tensile test. It was shown that the laser beam machining could be a useful tool to fabricate the specimens and this technique will be developed for the fabrication of various types of irradiated specimens in a hotcell.

A Study on Mechanical behavior of Tensile Specimen Fabricated by Laser Cutting

International Nuclear Information System (INIS)

Jin, Y. G.; Kim, G. S.; Baik, S. J.; Baek, S. Y.

2016-01-01

The mechanical testing data are required for the assessment of dry storage of the spent nuclear fuel. Laser cutting system could be useful tools for material processing such as cutting in radioactive environment due to non-contact nature, ease in handling and the laser cutting process is most advantageous, offering the narrow kerf width and heat affected zone by using small beam spot diameter. The feasibility of the laser cutting system was demonstrated for the fabrication of various types of the unirradiated cladding with and without oxide layer on the specimens. In the present study, the dimensional measurement and tensile test were conducted to investigate the mechanical behavior of the axial tensile test specimens depending on the material processing methods in a hot cell at IMEF (Irradiated Materials Examination Facility) of KAERI. Laser cutting system was used to fabricate the tensile test specimens, and the mechanical behavior was investigated using the dimensional measurement and tensile test. It was shown that the laser beam machining could be a useful tool to fabricate the specimens and this technique will be developed for the fabrication of various types of irradiated specimens in a hotcell

Tensile Bond Strength of Metal Bracket Bonding to Glazed Ceramic Surfaces With Different Surface Conditionings

Directory of Open Access Journals (Sweden)

M. Imani

2011-12-01

Full Text Available Objective: The objective of this study was to compare the tensile bond strength of metal brackets bonding to glazed ceramic surfaces using three various surface treatments.Materials and Methods: Forty two glazed ceramic disks were assigned to three groups. In the first and second groups the specimens were etched with 9.5% hydrofluoric acid (HFA. Subsequently in first group, ceramic primer and adhesive were applied, but in second group a bonding agent alone was used. In third group, specimens were treated with 35% phosphoric acid followed by ceramic primerand adhesive application. Brackets were bonded with light cure composites. The specimens were stored in distilled water in the room temperature for 24 hours and thermocycled 500 times between 5°C and 55°C. The universal testing machine was used to test the tensile bond strength and the adhesive remenant index scores between three groups was evaluated. The data were subjected to one-way ANOVA, Tukey and Kruskal-Wallis tests respectively.Results: The tensile bond strength was 3.69±0.52 MPa forfirst group, 2.69±0.91 MPa for second group and 3.60±0.41 MPa for third group. Group II specimens showed tensile strength values significantly different from other groups (P<0.01.Conclusion: In spite of limitations in laboratory studies it may be concluded that in application of Scotch bond multipurpose plus adhesive, phosphoric acid can be used instead of HFA for bonding brackets to the glazed ceramic restorations with enough tensile bond strength.

Evaluation of Fatigue Behavior and Surface Characteristics of Aluminum Alloy 2024 T6 After Electric Discharge Machining

Science.gov (United States)

Mehmood, Shahid; Shah, Masood; Pasha, Riffat Asim; Sultan, Amir

2017-10-01

The effect of electric discharge machining (EDM) on surface quality and consequently on the fatigue performance of Al 2024 T6 is investigated. Five levels of discharge current are analyzed, while all other electrical and nonelectrical parameters are kept constant. At each discharge current level, dog-bone specimens are machined by generating a peripheral notch at the center. The fatigue tests are performed on four-point rotating bending machine at room temperature. For comparison purposes, fatigue tests are also performed on the conventionally machined specimens. Linearized SN curves for 95% failure probability and with four different confidence levels (75, 90, 95 and 99%) are plotted for each discharge current level as well as for conventionally machined specimens. These plots show that the electric discharge machined (EDMed) specimens give inferior fatigue behavior as compared to conventionally machined specimen. Moreover, discharge current inversely affects the fatigue life, and this influence is highly pronounced at lower stresses. The EDMed surfaces are characterized by surface properties that could be responsible for change in fatigue life such as surface morphology, surface roughness, white layer thickness, microhardness and residual stresses. It is found that all these surface properties are affected by changing discharge current level. However, change in fatigue life by discharge current could not be associated independently to any single surface property.

Studies on fatigue life enhancement of pre-fatigued spring steel specimens using laser shock peening

International Nuclear Information System (INIS)

Ganesh, P.; Sundar, R.; Kumar, H.; Kaul, R.; Ranganathan, K.; Hedaoo, P.; Raghavendra, G.; Anand Kumar, S.; Tiwari, P.; Nagpure, D.C.; Bindra, K.S.; Kukreja, L.M.; Oak, S.M.

2014-01-01

Highlights: • Laser peening significantly extended fatigue life of pre-fatigued spring steel. • Increase in fatigue life of laser peened specimens was more than 15 times. • Black PVC tape is an effective coating for laser peening of ground surfaces. • Repeat peening repaired local surface melted regions on laser peened surface. • Technique is effective for life extension of in-service automobile parts. - Abstract: SAE 9260 spring steel specimens after enduring 50% of their mean fatigue life were subjected to laser shock peening using an in-house developed 2.5 J/7 ns pulsed Neodymium-doped Yttrium Aluminum Garnet (Nd:YAG) laser for studying their fatigue life enhancement. In the investigated range of process parameters, laser shock peening resulted in the extension of fatigue life of these partly fatigue damaged specimens by more than 15 times. Contributing factors for the enhanced fatigue life of laser peened specimens are: about 400 μm thick compressed surface layer with magnitude of surface stress in the range of −600 to −700 MPa, about 20% increase in surface hardness and unaltered surface finish. For laser peening of ground steel surface, an adhesive-backed black polyvinyl chloride (PVC) tape has been found to be a superior sacrificial coating than conventionally used black paint. The effect of repeated laser peening treatment was studied to repair locally surface melted regions and the treatment has been found to be effective in re-establishing desired compressive stress pattern on the erstwhile tensile-stressed surface

An Evaluation of the Cobas4800 HPV Test on Cervico-Vaginal Specimens in Liquid versus Solid Transport Media.

Directory of Open Access Journals (Sweden)

Hongxue Luo

Full Text Available Determine the ability of the Cobas 4800 assay to detect high-risk human papillomavirus (HrHPV and high-grade cervical lesions when using cervico-vaginal samples applied to liquid medium and solid media cards compared to a direct cervical sample.Two cervico-vaginal specimens (pseudo self-collected were obtained from 319 women. One was applied to an iFTA Card (FTA then the brush placed in liquid-based medium (LSELF; the other was applied to a new solid media: POI card (POI. The clinical performance of Cobas4800 assay using the three aforementioned specimens was compared to direct collected endocervical specimens in liquid media (LDOC.The overall agreements of HrHPV detection were 84.2% (LSELF vs. LDOC, 81.0% (FTA vs. LDOC, and 82.3% (POI vs. LDOC. LSELF, FTA and POI identified 98.0%, 79.6%, and 97.5% positive cases of LDOC. Sensitivity to identify CIN2+ were 98.4% (LSELF, 73.8% (FTA, 95.1% (POI, and 93.4% (LDOC respectively. FTA had 78.1% and 90.4% agreement with the LSELF samples for all HrHPV and HPV16/18 detection respectively, while POI had 91.6% for both.Cobas4800 HPV test combined with cervico-vaginal specimens applied to both liquid media and POI solid card are accurate to detect HrHPV infection and high-grade cervical lesions as compared with direct endocervical samples in liquid media.

An Evaluation of the Cobas4800 HPV Test on Cervico-Vaginal Specimens in Liquid versus Solid Transport Media.

Science.gov (United States)

Luo, Hongxue; Du, Hui; Maurer, Kathryn; Belinson, Jerome L; Wang, Guixiang; Liu, Zhihong; Zhang, Lijie; Zhou, Yanqiu; Wang, Chun; Tang, Jinlong; Qu, Xinfeng; Wu, Ruifang

2016-01-01

Determine the ability of the Cobas 4800 assay to detect high-risk human papillomavirus (HrHPV) and high-grade cervical lesions when using cervico-vaginal samples applied to liquid medium and solid media cards compared to a direct cervical sample. Two cervico-vaginal specimens (pseudo self-collected) were obtained from 319 women. One was applied to an iFTA Card (FTA) then the brush placed in liquid-based medium (LSELF); the other was applied to a new solid media: POI card (POI). The clinical performance of Cobas4800 assay using the three aforementioned specimens was compared to direct collected endocervical specimens in liquid media (LDOC). The overall agreements of HrHPV detection were 84.2% (LSELF vs. LDOC), 81.0% (FTA vs. LDOC), and 82.3% (POI vs. LDOC). LSELF, FTA and POI identified 98.0%, 79.6%, and 97.5% positive cases of LDOC. Sensitivity to identify CIN2+ were 98.4% (LSELF), 73.8% (FTA), 95.1% (POI), and 93.4% (LDOC) respectively. FTA had 78.1% and 90.4% agreement with the LSELF samples for all HrHPV and HPV16/18 detection respectively, while POI had 91.6% for both. Cobas4800 HPV test combined with cervico-vaginal specimens applied to both liquid media and POI solid card are accurate to detect HrHPV infection and high-grade cervical lesions as compared with direct endocervical samples in liquid media.

Biocompatibility of surface treated pure titanium and titanium alloy by in vivo and in vitro test

Science.gov (United States)

Lee, Min-Ho; Yoon, Dong-Joo; Won, Dae-Hee; Bae, Tae-Sung; Watari, Fumio

2003-02-01

In the present study, commercial pure Ti and Ti-6Al-4V alloy specimens with and without alkali and heat treatments were implanted in the abdominal connective tissue of mice. Conventional stainless steel 316L was also implanted for comparison. After three months, their biocompatibility was evaluated by in vitro and in vivo experiments. Surface structural changes of specimens due to the alkali treatment and soaking in Hank's solution were analyzed by XRD, SEM, XPS and AES. An apatite layer, which accelerates the connection with bone, was formed more easily on the alkali treated specimens than the non-treated specimens. The number of macrophages, which is known to increase as the inflammatory reaction proceeds, was much lower for the alkali and heat treated specimens than for the others. The average thickness of the fibrous capsule formed around the implant was much thinner for the alkali and heat treated specimens than for the others.

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.

Tensile testing grips are easily assembled under liquid nitrogen

Science.gov (United States)

Skalka, R. J.; Vandergrift, E. F.

1967-01-01

Split-screw grips for tensile testing provide uniform loading on the specimen shoulders. Holes in the heads enable the screws and specimen to be threaded as an assembly into a grip body, closely controlled guides and seats afford positive seating, and precision machining of mating surfaces minimizes misalignment effects.

Construction and performance test of apparatus for permeation experiments with controlled surfaces

International Nuclear Information System (INIS)

Hatano, Yuji; Nomura, Mamoru; Watanabe, Kuniaki; Livshits, Alexander I.; Busnyuk, Andrei O.; Nakamura, Yukio; Ohyabu, Nobuyoshi

2003-01-01

A new apparatus was constructed to examine gas-, atom- and plasma-driven permeation of hydrogen isotopes through group VA metal membranes with precisely controlled surface states. Absorption and desorption experiments are also possible. The new apparatus consists of two vacuum chambers, an upstream chamber and a downstream chamber, separated by a specimen membrane. Both chambers are evacuated by turbo-molecular pumps and sputter-ion pumps. The upstream chamber is equipped with Ta filaments serving as atomizers in atom-driven permeation experiments and cathodes in plasma-driven permeation experiments. The specimen membrane is formed into a tubular shape and electrically isolated from the chamber. Hence, ohmic heating of the membrane is possible, and this feature of the membrane is suitable for surface cleaning by high-temperature heating an impurity doping for the control of surface chemical composition through surface segregation. Both chambers were evacuated to 1 x 10 -7 Pa after baking. The main component of residual gas was H 2 , and the partial pressures of impurity gases other than H 2 were ca. 1 x 10 -8 Pa. Gas- and atom-driven permeation experiments were successfully carried out with hydrogen gas for Nb membrane activated by heating in vacuum at 1173 K. Superpermeation was observed in the atom-driven permeation experiments. Absorption experiments with a clean surface were also carried out. The surface was, however, cleaned only partially, because the temperature distribution was not uniform during high-temperature heating. Nevertheless, surface cleanliness was retained during absorption experiments under the present vacuum conditions. A new membrane assembly that will enable a uniform temperature distribution is now under construction. (author)

Deducing material quality in cast and hot-forged steels by new bending test

Science.gov (United States)

Valberg, Henry; Langøy, Morten; Nedreberg, Mette; Helvig, Torgeir

2017-10-01

A special bend test has been developed and applied for the purpose of characterization and comparison of the material ductility in crankpin steel discs manufactured by casting, or casting subsequently followed by hot open-die forging (ODF) or closed-die forging (CDF). The bending test specimen consists of a small rectangular plate of material with a round hole cut out in the middle. The "eye-shape" specimens were cut out from various positions either near to the surface of, or from the interior of the discs. The test method revealed differences in ductility for the investigated materials, and for different depth positions inside the discs. The roughening of the specimen surface on the top-side of the specimen bend also varied dependent on the processing method for the material. Current results show that this test method is useful for evaluation of material quality in differently processed material. Experimental bend test results are presented for differently processed variants of the same material, i.e., crankpin discs either made by solely casting or casting subsequently followed by hot working either by ODF or CDF.

Jet-Surface Interaction - High Aspect Ratio Nozzle Test: Test Summary

Science.gov (United States)

Brown, Clifford A.

2016-01-01

The Jet-Surface Interaction High Aspect Ratio Nozzle Test was conducted in the Aero-Acoustic Propulsion Laboratory at the NASA Glenn Research Center in the fall of 2015. There were four primary goals specified for this test: (1) extend the current noise database for rectangular nozzles to higher aspect ratios, (2) verify data previously acquired at small-scale with data from a larger model, (3) acquired jet-surface interaction noise data suitable for creating verifying empirical noise models and (4) investigate the effect of nozzle septa on the jet-mixing and jet-surface interaction noise. These slides give a summary of the test with representative results for each goal.

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.)

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

Standard test method for crack-tip opening displacement (CTOD) fracture toughness measurement

CERN Document Server

American Society for Testing and Materials. Philadelphia

2008-01-01

1.1 This test method covers the determination of critical crack-tip opening displacement (CTOD) values at one or more of several crack extension events, and may be used to measure cleavage crack initiation toughness for materials that exhibit a change from ductile to brittle behavior with decreasing temperature, such as ferritic steels. This test method applies specifically to notched specimens sharpened by fatigue cracking. The recommended specimens are three-point bend [SE(B)], compact [C(T)], or arc-shaped bend [A(B)] specimens. The loading rate is slow and influences of environment (other than temperature) are not covered. The specimens are tested under crosshead or clip gage displacement controlled loading. 1.1.1 The recommended specimen thickness, B, for the SE(B) and C(T) specimens is that of the material in thicknesses intended for an application. For the A(B) specimen, the recommended depth, W, is the wall thickness of the tube or pipe from which the specimen is obtained. Superficial surface machini...

How does the surface treatment change the cytocompatibility of implants made by selective laser melting?

Science.gov (United States)

Matouskova, Lucie; Ackermann, Michal; Horakova, Jana; Capek, Lukas; Henys, Petr; Safka, Jiri

2018-04-01

The study investigates the potential for producing medical components via Selective Laser Melting technology (SLM). The material tested consisted of the biocompatible titanium alloy Ti6Al4V. The research involved the testing of laboratory specimens produced using SLM technology both in vitro and for surface roughness. The aim of the research was to clarify whether SLM technology affects the cytocompatibility of implants and, thus, whether SLM implants provide suitable candidates for medical use following zero or minimum post-fabrication treatment. Areas covered: The specimens were tested with an osteoblast cell line and, subsequently, two post-treatment processes were compared: non-treated (as-fabricated) and glass-blasted. Interactions with MG-63 cells were evaluated by means of metabolic MTT assay and microscope techniques (scanning electron microscopy, fluorescence microscopy). Surface roughness was observed on both the non-treated and glass-blasted SLM specimens. Expert Commentary: The research concluded that the glass-blasting of SLM Ti6Al4V significantly reduces surface roughness. The arithmetic mean roughness Ra was calculated at 3.4 µm for the glass-blasted and 13.3 µm for the non-treated surfaces. However, the results of in vitro testing revealed that the non-treated surface was better suited to cell growth.

Technology development on production of test specimens from irradiated capsule outer-tube and mechanical evaluation test of stainless steel with high dose carried out by the technology

International Nuclear Information System (INIS)

Hayashi, Koji; Shibata, Akira; Iwamatsu, Shigemi; Sozawa, Shizuo; Takada, Fumiki; Ohmi, Masao; Nakagawa, Tetsuya

2008-03-01

The irradiation capsule 74M-52J was irradiated during total 136 cycles at reactor core of JMTR and the maximum neutron dose reached on 3.9x10 26 n/m 2 at the capsule outer-tube made of a type 304 stainless steel. In order to produce mechanical test specimens from the outer-tube, a punching technique was developed as a simple remote-handling method in a hot-cell. From comparison between the punching and the mechanical cutting methods, it was clarified that the punching technique was applicable to practical use. Moreover, an evaluation test of mechanical properties using specimens sampled from the 74M-52 was performed with in-water high temperature condition, less than 288degC. The result shows that the residual elongation is 18% at 150degC and 13% at 288degC. It was confirmed that the type 304 stainless steel irradiated up to such high dose shows enough ductility. (author)

Study of residual stresses in CT test specimens welded by electron beam

Science.gov (United States)

Papushkin, I. V.; Kaisheva, D.; Bokuchava, G. D.; Angelov, V.; Petrov, P.

2018-03-01

The paper reports result of residual stress distribution studies in CT specimens reconstituted by electron beam welding (EBW). The main aim of the study is evaluation of the applicability of the welding technique for CT specimens’ reconstitution. Thus, the temperature distribution during electron beam welding of a CT specimen was calculated using Green’s functions and the residual stress distribution was determined experimentally using neutron diffraction. Time-of-flight neutron diffraction experiments were performed on a Fourier stress diffractometer at the IBR-2 fast pulsed reactor in FLNP JINR (Dubna, Russia). The neutron diffraction data estimates yielded a maximal stress level of ±180 MPa in the welded joint.

Thermal expansion of epoxy-fiberglass composite specimens

International Nuclear Information System (INIS)

McElroy, D.L.; Weaver, F.J.; Bridgman, C.

1986-01-01

The thermal expansion behavior of three epoxy-fiberglass composite specimens was measured from 20 to 120 0 C (70 to 250 0 F) using a fused quartz push-rod dilatometer. Billets produced by vacuum impregnating layers of two types of fiberglass cloth with an epoxy resin were core-drilled to produce cylindrical specimens. These were used to study expansion perpendicular and parallel to the fiberglass layers. The dilatometer is held at a preselected temperature until steady-state is indicated by stable length and temperature data. Before testing the composite specimens, a reliability check of the dilatometer was performed using a copper secondary standard. This indicated thermal expansion coefficient (α) values within +-2% of expected values from 20 to 200 0 C

Measurement of temperature fields in specimens of quartz ceramic during surface ablation

Science.gov (United States)

Frolov, G. A.; Pasichnyi, V. V.; Suzdal'Tsev, E. I.; Tsyganenko, V. S.

1989-08-01

The authors propose a method of mounting thermocouples and have obtained temperature fields within specimens of pure and doped quartz ceramic. The linearity of the dependenceΔ * = fleft( {sqrt tau } right) for deep isotherms has been proved experimentally.

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

An In Vitro Evaluation of Alumina, Zirconia, and Lithium Disilicate Surface Roughness Caused by Two Scaling Instruments.

Science.gov (United States)

Vigolo, Paolo; Buzzo, Ottavia; Buzzo, Maurizio; Mutinelli, Sabrina

2017-02-01

Plaque control is crucial for the prevention of inflammatory periodontal disease. Hand scaling instruments have been shown to be efficient for the removal of plaque; however, routine periodontal prophylactic procedures may modify the surface profile of restorative materials. The purpose of this study was to assess in vitro the changes in roughness of alumina, zirconia, and lithium disilicate surfaces treated by two hand scaling instruments. Forty-eight alumina specimens, 48 zirconia specimens, and 48 lithium disilicate specimens, were selected. All specimens were divided into three groups of 16 each; one group for each material was considered the control group and no scaling procedures were performed; the second group of each material was exposed to scaling with steel curettes simulating standard clinical conditions; the third group of each material was exposed to scaling with titanium curettes. After scaling, the surface roughness of the specimens was evaluated with a profilometer. First, a statistical test was carried out to evaluate the difference in surface roughness before the scaling procedure of the three materials was effected (Kruskal-Wallis test). Subsequently, the effect of curette material (steel and titanium) on roughness difference and roughness ratio was analyzed throughout the entire sample and within each material group, and a nonparametric test for dependent values was conducted (Wilcoxon signed-rank test). Finally, the roughness ratios of the three material groups were compared by means of a Kruskal-Wallis test and a Wilcoxon signed-rank test. Upon completion of profilometric evaluation, representative specimens from each group were prepared for SEM evaluation to evaluate the effects of the two scaling systems on the different surfaces qualitatively. After scaling procedure, the roughness profile value increased in all disks. Classifying the full sample according to curette used, the roughness of the disks treated with a steel curette reached a

Detection of tightly closed flaws by nondestructive testing (NDT) methods in steel and titanium

Science.gov (United States)

Rummel, W. D.; Rathke, R. A.; Todd, P. H., Jr.; Tedrow, T. L.; Mullen, S. J.

1976-01-01

X-radiographic, liquid penetrant, ultrasonic, eddy current and magnetic particle testing techniques were optimized and applied to the evaluation of 4340 steel (180 KSI-UTS) and 6Al-4V titanium (STA) alloy specimens. Sixty steel specimens containing a total of 176 fatigue cracks and 60 titanium specimens containing a total of 135 fatigue cracks were evaluated. The cracks ranged in length from .043 cm (0.017 inch) to 1.02 cm (.400 inch) and in depth from .005 cm (.002 inch) to .239 cm (.094 inch) for steel specimens. Lengths ranged from .048 cm (0.019 inch) to 1.03 cm (.407 inch) and depths from 0.010 cm (.004 inch) to .261 cm (0.103 inch) for titanium specimens. Specimen thicknesses were nominally .152 cm (0.060 inch) and 0.635 cm (0.250 inch) and surface finishes were nominally 125 rms. Specimens were evaluated in the "as machined" surface condition, after etch surface and after proof loading in a randomized inspection sequence.

Effect of two-step and one-step surface conditioning of glass ceramic on adhesion strength of orthodontic bracket and effect of thermo-cycling on adhesion strength.

Science.gov (United States)

Asiry, Moshabab A; AlShahrani, Ibrahim; Alaqeel, Samer M; Durgesh, Bangalore H; Ramakrishnaiah, Ravikumar

2018-08-01

The adhesion strength of orthodontic brackets bonded to dental glass ceramics was evaluated after ceramic surface was treated with two-step and one-step surface conditioning systems, and subjecting to thermo-cycling. A total of forty specimens were fabricated from silica based glass ceramic (lithium disilicate) by duplicating the buccal surface of maxillary first premolar. The specimens were randomly assigned to two experimental groups (n = 20), group one specimens were treated with two-step surface conditioning system (IPS ceramic etching gel™ and Monobond plus™) and group two specimens were treated with one-step surface conditioning system (Monobond etch and prime™). The surface roughness of the specimens after treatment with two-step and one-step surface conditioning system was measured using non-contact surface profilometer. Ten randomly selected specimens from each group were subjected to thermo-cycling and the remaining ten served as baseline. The shear bond strength of the specimens was measured using universal material testing machine. The adhesive remnant index score was calculated, and the results of surface roughness and bond strength were tabulated and subjected to analysis of variance and post hoc tukey's test at a significance level of p step conditioning system had higher surface roughness and bond strength than one-step conditioning system. The majority of the specimens treated with both two-step and one-step conditioned specimens showed adhesive failure after subjecting thermo-cycling. Traditional two-step conditioning provides better bond strength. The clinical importance of the study is that, the silane promoted adhesion significantly reduces on exposure to thermo-cycling. Copyright © 2018 Elsevier Ltd. All rights reserved.

Airflow resistivity instrument for in situ measurement on the earth's ground surface

Science.gov (United States)

Zuckerwar, A. J.

1983-01-01

An airflow resistivity instrument features a novel specimen holder, especially designed for in situ measurement on the earth's ground surface. This capability eliminates the disadvantages of prior intrusive instruments, which necessitate the removal of a test specimen from the ground. A prototype instrument can measure airflow resistivities in the range 10-5000 cgs rayl/cm, at specimen depths up to 15.24 cm (6 in.), and at differential pressures up to 2490.8 dyn sq cm (1 in. H2O) across the specimen. Because of the close relationship between flow resistivity and acoustic impedance, this instrument should prove useful in acoustical studies of the earth's ground surface. Results of airflow resistivity measurements on an uncultivated grass field for varying values of moisture content are presented.

Applicability evaluation of eddy current testing for underwater laser beam welding

International Nuclear Information System (INIS)

Kobayashi, Noriyasu; Kasuya, Takashi; Ueno, Souichi; Ochiai, Makoto; Yuguchi, Yasuhiro

2010-01-01

We clarified a defect detecting capability of eddy current testing (ECT) as a surface inspection technique for underwater laser beam welding. An underwater laser beam welding procedure includes groove caving as a preparation, laser beam welding in groove and welding surface grinding as a post treatment. Therefore groove and grinded welding surface inspections are required underwater. We curried out defect detection tests using three kinds of specimens simulated a groove, reactor vessel nozzle dissimilar metal welding materials and a laser beam welding material with a cross coil ECT probe. From experimental results, we confirmed that it is possible to detect 0.3 mm or more depth electro-discharge machining slits on machining surfaces in all specimens and an ECT has possibility as a surface inspection technique for underwater laser beam welding. (author)

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

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

Specimen rejection in laboratory medicine: Necessary for patient safety?

Science.gov (United States)

Dikmen, Zeliha Gunnur; Pinar, Asli; Akbiyik, Filiz

2015-01-01

The emergency laboratory in Hacettepe University Hospitals receives specimens from emergency departments (EDs), inpatient services and intensive care units (ICUs). The samples are accepted according to the rejection criteria of the laboratory. In this study, we aimed to evaluate the sample rejection ratios according to the types of pre-preanalytical errors and collection areas. The samples sent to the emergency laboratory were recorded during 12 months between January to December, 2013 in which 453,171 samples were received and 27,067 specimens were rejected. Rejection ratios was 2.5% for biochemistry tests, 3.2% for complete blood count (CBC), 9.8% for blood gases, 9.2% for urine analysis, 13.3% for coagulation tests, 12.8% for therapeutic drug monitoring, 3.5% for cardiac markers and 12% for hormone tests. The most frequent rejection reasons were fibrin clots (28%) and inadequate volume (9%) for biochemical tests. Clotted samples (35%) and inadequate volume (13%) were the major causes for coagulation tests, blood gas analyses and CBC. The ratio of rejected specimens was higher in the EDs (40%) compared to ICUs (30%) and inpatient services (28%). The highest rejection ratio was observed in neurology ICU (14%) among the ICUs and internal medicine inpatient service (10%) within inpatient clinics. We detected an overall specimen rejection rate of 6% in emergency laboratory. By documentation of rejected samples and periodic training of healthcare personnel, we expect to decrease sample rejection ratios below 2%, improve total quality management of the emergency laboratory and promote patient safety.

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.)

Comparative evaluation of tensile bond strength of silicone-based denture liners after thermocycling and surface treatment.

Science.gov (United States)

Kaur, Harsimran; Datta, Kusum

2015-01-01

To examine, evaluate, and compare the tensile bond strength of two silicone-based liners; one autopolymerizing and one heat cured, when treated with different chemical etchants to improve their adhesion with denture base resin. Hundred and sixty test specimens of heat-cured polymethyl methacrylate (PMMA) were fabricated; out of which 80 specimens were tested for tensile bond strength after bonding it to autopolymerizing resilient liner (Ufigel P) and rest 80 to heat-cured resilient liner (Molloplast B). Each main group was further divided into four subgroups of 20 specimens each, one to act as a control and three were subjected to surface treatment with different chemical etchants namely dichloromethane, MMA monomer, and chloroform. The two silicone-based denture liners were processed between 2 PMMA specimens (10 mm × 10 mm × 40 mm) in the space provided by a spacer of 3 mm, thermocycled (5-55°C) for 500 cycles, and then their tensile strength measurements were done in the universal testing machine. One-way ANOVA technique showed a highly significant difference in the mean tensile bond strength values for all the groups. The Student's t-test computed values of statistics for the compared groups were greater than the critical values both at 5% and at 1% levels. Surface treatment of denture base resin with chemical etchants prior to the application of silicone-based liner (Ufigel P and Molloplast-B) increased the tensile bond strength. The increase was the highest with specimens subjected to 180 s of MMA surface treatment and the lowest with control group specimens.

Load bearing and deformation behaviour of dynamically loaded wide plate specimens

International Nuclear Information System (INIS)

Julisch, P.; Haedrich, H.J.; Stadtmueller, W.; Sturm, D.

1989-01-01

For the testing of large-scale specimens, a 12 MN-High Loading Rate Tensile Testing Machine was designed and built at MPA Stuttgart. The aim was to determine the influence of high loading rates on the stress and strain behaviour of unwelded and welded components of ferritic and austenitic materials. This new generation of testing machines is driven by a propellant charge, and generates a maximum tensile force of 12 MN with a piston velocity of 25 m/s after a stroke of 20 mm, or a maximum velocity of 60 m/s after a stroke of 400 mm. In a first test programme, welded and unwelded wide plate specimens made of material X 6 CrNi 18 11 were tested at room temperature with different strain rates from 10 -3 /s to 63/s. In addition to a description of the 12 MN-High Loading Rate Tensile Testing Machine, the results of the high loading rate tensile tests performed will be presented and compared with quasistatically tested wide plate specimens. (orig.)

Surface discoloration of composite resins: Effects of staining and bleaching.

Science.gov (United States)

Poggio, Claudio; Beltrami, Riccardo; Scribante, Andrea; Colombo, Marco; Chiesa, Marco

2012-09-01

The purpose of this in vitro study was to evaluate surface discoloration of three microhybrid composite resins (Esthet•X HD, Clearfil AP-X, Gradia Direct) and five nanohybrid composite resins (Ceram•X, GC Kalore, G-aenial, Grandio, GrandioSO), after staining and bleaching procedures. The composite resins were polymerized with a curing light (Celalux II, Voco, Cuxhaven, Germany) into 160 silicon molds (6,4 mm in diameter and 2 mm in thickness) to obtain identical specimens. Twenty samples for each composite resin were prepared. The specimens were polished using an automated polishing machine with the sequence of 600-, 800-, 1000-grit abrasive paper under water irrigation. The specimens were immersed in tea and distilled water: the specimens were dipped for 20 min, once a day (every 24 h), for 14 days into the drinks. The specimens were then bleached with carbamide peroxide at 17% (Perfect Bleach-Voco). The color of specimens was measured with a spectrophotometer according to the CIE L(*)a(*)b(*) system after light-polymerization of composite resin specimens, after 7 days, after 14 days, and after bleaching. The color difference h index (DEab(*)) between each measurement was calculated. Statistical analysis was made using analysis of variance (ANOVA). All specimens showed a significant increase in staining with a similar trend and no significant differences between microhybrid and nanohybrid composite resins. After whitening procedures, materials tested showed both significant and unsignificant differences of the h index. Microhybrid and nanohybrid composite resins had similar in vitro surface discoloration in tea. After bleaching, discoloration was removed from some composite resins tested.

Tribology and hydrophobicity of a biocompatible GPTMS/PFPE coating on Ti6Al4V surfaces.

Science.gov (United States)

Panjwani, Bharat; Sinha, Sujeet K

2012-11-01

Tribological properties of perfluoropolyether (PFPE) coated 3-glycidoxypropyltrimethoxy silane (GPTMS) SAMs (self-assembled monolayers) onto Ti6Al4V alloy substrate were studied using ball-on-disk experiments. GPTMS SAMs deposition onto a Ti6Al4V alloy surface was carried out using solution phase method. Ultra-thin layer of PFPE was dip-coated onto SAMs modified specimens. Tribological tests were carried out at 0.2 N normal load and rotational speed of 200 rpm using track radius of 2 mm. Wear track and counterface surface conditions were investigated using optical microscopy. PFPE modified specimens were baked at 150 °C for 1h to investigate the effect of thermal treatment on tribological properties. Surface characterization tests such as contact angle measurement, AFM morphology and X-ray photoelectron spectroscopy were carried out for differently modified specimens. PFPE overcoat meets the requirements of cytotoxicity test using the ISO 10993-5 elution method. PFPE top layer lowered the coefficient of friction and increased wear durability for different specimens (with and without GPTMS intermediate layer). PFPE overcoat onto GPTMS showed significant increase in the wear resistance compared with overcoat onto bare Ti6Al4V specimens. The observed improvement in the tribological properties can be attributed to the change in the interaction of PFPE molecules with the substrate surface due to the GPTMS intermediate layer. Copyright © 2012 Elsevier Ltd. All rights reserved.

Visualization test using piping group mock up specimen for evaluation of wastage phenomena in steam generator for FBR

International Nuclear Information System (INIS)

Kato, Keisuke; Yoshida, Atsuro; Arae, Kunihiko; Narabayashi, Tadashi; Ohshima, Hiroyuki; Kurihara, Akikazu

2012-01-01

There is a need for quantitative evaluation of wastage phenomena in steam generator for FBR. We focused attention on liquid droplet impingement erosion (LDIE) in wastage phenomena and performed basic study with piping group mock up specimen for quantitative evaluation of LDIE. First, we did visualization test of high pressure and high speed jet into the water. Test section mock up the crack of heat exchanger tube and neighboring heat exchanger tubes. We did the test under the following test conditions. Upstream pressure is 0.3MPa, vapor temperature is 300K, crack width is 0.1mm, and crack length is 40mm. (crack diameter is 0.2mm) Second, we did pressure and temperature measurement test in the same test conditions as before. We evaluated jet behavior at test section by those two tests. In addition, we did two phase flow analysis of the jet with TRAC code. (author)

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)

Culturing Stool Specimens for Campylobacter spp., Pennsylvania, USA

Science.gov (United States)

M’ikanatha, Nkuchia M.; Dettinger, Lisa A.; Perry, Amanda; Rogers, Paul; Reynolds, Stanley M.

2012-01-01

In 2010, we surveyed 176 clinical laboratories in Pennsylvania regarding stool specimen testing practices for enteropathogens, including Campylobacter spp. Most (96.3%) routinely test for Campylobacter spp. In 17 (15.7%), a stool antigen test is the sole method for diagnosis. We recommend that laboratory practice guidelines for Campylobacter spp. testing be developed. PMID:22377086

Fatigue behaviour of 304L steel welded structures: influence of residual stresses and surface mechanical finishing

International Nuclear Information System (INIS)

Magnier-Monin, L.

2007-12-01

This study focuses on the influence of residual stresses and surface mechanical finishing on lifetime of stainless steel 304L welded structures. Residual stresses are determined on specific specimens of three types: base-metal, as-welded and ground-welded specimens. Each type is submitted to fatigue tests in order to assess the influence of these parameters on the lifetime, and to determine their evolution. The experiments show that an important surface stress concentration is located in the weld root of as-welded structures, which has a negative effect on the fatigue life. The grinding operation generates high-level surface residual stresses but the lifetime is higher thanks to the reduction of the notch effect. The fatigue test results are compared to the nuclear industry best-fit S-N curves. This enables the determination of correction factors related to fatigue test results of polished specimens, and to assess the lifetime of structures. (author)

Three-Point Bending Tests of Zirconia Core/Veneer Ceramics for Dental Restorations

Directory of Open Access Journals (Sweden)

Massimo Marrelli

2013-01-01

Full Text Available Introduction. The mechanical strength and the surface hardness of commercially available yttrium-doped zirconia were investigated. Furthermore, a comparative study of eight different ceramic veneers, to be used for the production of two-layered all-ceramic restorative systems, was carried out. Materials and Methods. Four types of zirconia specimens were analyzed, according to a standard ISO procedure (ISO 6872. Besides, two-layered zirconia-veneer specimens were prepared for three-point bending tests. Results. A strong effect of the surface roughness on the mechanical strength of zirconia specimens was observed. Finally, a comparative study of eight commercially available veneering ceramics shows different modes of failure between the selected veneers. Conclusion. The results indicate that close attention should be paid to the preparation of zirconia-based crowns and bridges by CAD/CAM process, because surface roughness has an important effect on the mechanical strength of the material. Finally, the results of the mechanical tests on two-layered specimens represent an important support to the choice of the veneering ceramic.

The impact of irradiation induced specimen charging on microanalysis in a scanning electron microscope

International Nuclear Information System (INIS)

Stevens-Kalceff, M.A.

2003-01-01

Full text: It is necessary to assess and characterize the perturbing influences of experimental probes on the specimens under investigation. The significant influence of electron beam irradiation on poorly conducting materials has been assessed by a combination of specialized analytical scanning electron and scanning probe microscopy techniques including Cathodoluminescence Microanalysis and Kelvin Probe Microscopy. These techniques enable the defect structure and the residual charging of materials to be characterized at high spatial resolution. Cathodoluminescence is the non-incandescent emission of light resulting from the electron irradiation. CL microscopy and spectroscopy in a Scanning Electron Microscope (SEM) enables high spatial resolution and high sensitivity detection of defects in poorly conducting materials. Local variations in the distribution of defects can be non-destructively characterized with high spatial (lateral and depth) resolution by adjusting electron beam parameters to select the specimen micro-volume of interest. Kelvin Probe Microscopy (KPM) is a Scanning Probe Microscopy technique in which long-range Coulomb forces between a conductive atomic force probe and the specimen enable the surface potential to be characterized with high spatial resolution. A combination of Kelvin Probe Microscopy (KPM) and Cathodoluminescence (CL) microanalysis has been used to characterize ultra pure silicon dioxide exposed to electron irradiation in a Scanning Electron Microscope. Silicon dioxide is an excellent model specimen with which to investigate charging induced effects. It is a very poor electrical conductor, homogeneous and electron irradiation produces easily identifiable surface modification which enables irradiated regions to be easily and unambiguously located. A conductive grounded coating is typically applied to poorly conducting specimens prior to investigation in an SEM to prevent deflection of the electron beam and surface charging, however

Estimations of creep behavior and failure life for a circumferentially notched specimen

International Nuclear Information System (INIS)

Kobayashi, Ken-ichi; Yokobori, Toshimitsu; Kikuchi, Kenji.

1997-01-01

No method with which to characterize and/or illustrate total creep behavior for specimens with notches, holes or cracks has been proposed. In this paper it is proposed that most creep curves can be drawn with a master curve for each creep test whenever test conditions and failure modes are similar to each other, and the lifetime ratio normalized by the rupture time is introduced. Using smooth and circumferentially notched specimens of 2.25 Cr-1 Mo steel, creep tests were performed at 600degC for examination of this concept. Furthermore, a θ projection method was used to describe creep curves for notched specimens and to extrapolate longer creep lives. Then, the whole creep curve shape for notched specimens could be easily drawn, except for that in the vicinity of the rupture point. However, longer creep lives of notched specimens were underestimated in comparison with a simple extrapolation of the experimental data. This resulted from the negative dependence of the parameter of θ 3 on the applied stress. (author)

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