Threshold values characterizing iodine-induced SCC of zircaloys

International Nuclear Information System (INIS)

Une, K.

1981-01-01

In this paper, threshold values of stress, stress intensity factor, strain, strain rate and iodine concentration for SCC of unirradiated and irradiated Zircaloys are reviewed. The ratio of σ sub(th)/σ sub(y) adequately represents the effects of cold-work and irradiation on the SCC susceptibility, where threshold stress σ sub(th) is defined as the minimum stress to cause SCC to failure after 10-20 hours and σ sub(y), the yield stress obtained in an inert atmosphere. The ratio becomes gradually smaller with larger σ sub(y) and is less than 1 for materials with yield strengths above about 350MPa. Plastic strain appears to be necessary for SCC; plastic strains to failure range from 0.1 to 1% for high strength materials, even when data for irradiated materials are included. Strain rate significantly affects the susceptibility. A comparison of SCC data between constant strain rate and constant stress tests is presented. (author)

Performance characteristics of SCC radioimmunoassay and clinical significance serum SCC Ag assay in patients with malignancy

International Nuclear Information System (INIS)

Kim, Dong Youn

1986-01-01

To evaluate the performance characteristics of SCC RIV and the clinical significance of serum SCC Ag assay in patients with malignancy, serum SCC Ag levels were measured by SCC RIV kit in 40 normal controls and 35 percents with various untreated malignancy, who visited Chonju Presbyterian Medical Center. The results were as follows; 1. The SCC RIA was simple to perform and can be completed in two workday. And the standard curve and reproducibility were both good. 2. The mean serum SCC Ag level in normal controls was 1.64 ± 0.93 ng/mL and normal upper limit of serum SCC Ag was defined as 2.6 ng/mL. 3 out of 40 (7.5%) normal controls showed elevated SCC Ag levels above the normal upper limit. 3. In 35 patients with various untreated malignancy, 18 patients (51.4%) showed elevated serum SCC Ag levels, 59.1% of 22 patients with cervical cancer, 80% of 5 patients with lung cancer, 33% of 3 patients with esophageal cancer, 0% of 2 patients with rectal cancer and 0% of 3 patients with breast cancer showed elevated serum SCC Ag levels. Above results represent that SCC RIV is simple method to perform followed by good standard curve and reproducibility, and may be a useful indicator reflecting diagnostic data of patients with cervical cancer and lung cancer

Developments in SCC Mitigation by Electrocatalysis

Science.gov (United States)

Andresen, Peter L.; Kim, Young J.

SCC is strongly influenced by water chemistry parameters, especially when crack chemistry can be concentrated from differential aeration or thermal gradients or boiling. Mitigation of the effects of the high corrosion potential associated with oxidants is markedly and efficiently accomplished by electrocatalysis, which requires that there be a stoichiometric excess of reductants over oxidants. Mechanisms and criteria for effective SCC mitigation are summarized, with particular focus on the critical location for the catalyst in a crack and experimental support for these concepts. Optimization of electrocatalysis by OnLine NobleChem- is described, for example where Pt is injected at levels of 0.002 to 0.05 ppb in the reactor water.

Investigation on potential SCC in gas transmission pipeline in China

Energy Technology Data Exchange (ETDEWEB)

Jian, S. [Petroleum Univ., Beijing (China); Zupei, Y.; Yunxin, M. [China Petroleum Pipeline Corp., Beijing (China). Science and Technology Center

2004-07-01

Stress corrosion cracking (SCC) is a common phenomenon that occurs on the outer surfaces of buried pipelines. This paper investigated aspects of SCC on 3 transmission pipelines on the West-East Gas Pipeline Project in China. The study was comprised of 3 different investigations: (1) an investigation of SCC cases on constructed pipelines; (2) an evaluation of SCC sensitivity of pipeline steels in typical soil environments; and (3) an analysis of soil environments and operation conditions of western pipelines. The study included a review of pipeline corrosion investigations, as well as an examination of pipeline failure cases. Investigative digs were conducted at 21 sites to test soil chemistries. Slow strain rate stress were conducted to evaluate SCC sensitivity of steel pipelines used in China. Potentiodynamic polarization tests were conducted to characterize the electrochemical behaviour of the X70 line pipe steel in different soil environments. Results of the study showed that the environmental conditions in many locations in China contributed to SCC in pipelines. SCC was observed on the surface of X70 steel pipe specimens in both marsh and saline environments. Seasonal temperature changes also contributed additional stress on pipelines. The movement of soil bodies in mountainous areas also contributed to stress and coating damage. It was concluded that proper cathodic protection can alleviate concentrations of local solutions under disbanded coatings. Overprotection of SCC will accelerate the growth of cracks and the degradation of coatings. Samples gathered from the solutions found under the disbanded coatings of pipelines will be used to form part of a reference database for predicting SCC in oil and gas pipelines in the future. 2 refs., 4 tabs., 5 figs.

Accelerated SCC Testing of Stainless Steels According to Corrosion Resistance Classes

Energy Technology Data Exchange (ETDEWEB)

Borchert, M.; Mori, G. [General Analytical and Physical Chemistry, Montanuniversitaet Leoben (Austria); Bischof, M.; Tomandl, A. [Hilti Corporation, Liechtenstein (Austria)

2015-12-15

The German Guidelines for stainless steel in buildings (Z.30.3-6) issued by the German Institute for Building Technology (DIBt) categorize various stainless steel grades into five corrosion resistance classes (CRCs). Only 21 frequently used grades are approved and assigned to these CRCs. To assign new or less commonly used materials, a large program of outdoor exposure tests and laboratory tests is required. The present paper shows the results of stress corrosion cracking (SCC) tests that can distinguish between different CRCs. Slow strain rate tests (SSRT) were performed in various media and at different temperatures. CRC IV could be distinguished from CRC II and CRC III with a 31.3 % Cl{sup -} as MgCl{sub 2} solution at 140 .deg. C. CRC II and CRC III could be differentiated by testing in a 30% Cl{sup -} as MgCl{sub 2} solution at 100 .deg. C.

Influence of deformation on SCC susceptibility of austenitic stainless steel in PWR primary water

Energy Technology Data Exchange (ETDEWEB)

Kaneshima, Yoshiari; Totsuka, Nobuo; Nakajima, Nobuo [Institute of Nuclear Safety System Inc., Mihama, Fukui (Japan)

2001-09-01

Slow strain rate tests (SSRT) were carried out to evaluate the SCC susceptibility of four types of austenitic stainless steels (SUS304, SUS316, SUS304L and SUS316L) in PWR primary water. The influence of deformation on SCC susceptibility of SUS316 was studied. All types of stainless steel were susceptible to SCC, and the SCC susceptibility varied depending on the steel type. The comparison of the SSRT results and tensile test in air based on the reduction of area measurement showed that the SCC susceptibility increased with increasing the degree of deformation. For explaining the influence of deformation on SCC susceptibility, it is necessary to evaluate both intergranular and transgranular fractures. (author)

Comparison of ANN and RKS approaches to model SCC strength

Science.gov (United States)

Prakash, Aravind J.; Sathyan, Dhanya; Anand, K. B.; Aravind, N. R.

2018-02-01

Self compacting concrete (SCC) is a high performance concrete that has high flowability and can be used in heavily reinforced concrete members with minimal compaction segregation and bleeding. The mix proportioning of SCC is highly complex and large number of trials are required to get the mix with the desired properties resulting in the wastage of materials and time. The research on SCC has been highly empirical and no theoretical relationships have been developed between the mixture proportioning and engineering properties of SCC. In this work effectiveness of artificial neural network (ANN) and random kitchen sink algorithm(RKS) with regularized least square algorithm(RLS) in predicting the split tensile strength of the SCC is analysed. Random kitchen sink algorithm is used for mapping data to higher dimension and classification of this data is done using Regularized least square algorithm. The training and testing data for the algorithm was obtained experimentally using standard test procedures and materials available. Total of 40 trials were done which were used as the training and testing data. Trials were performed by varying the amount of fine aggregate, coarse aggregate, dosage and type of super plasticizer and water. Prediction accuracy of the ANN and RKS model is checked by comparing the RMSE value of both ANN and RKS. Analysis shows that eventhough the RKS model is good for large data set, its prediction accuracy is as good as conventional prediction method like ANN so the split tensile strength model developed by RKS can be used in industries for the proportioning of SCC with tailor made property.

The effect of molybdenum addition on SCC susceptibility of stainless steels in oxygenated high temperature water

International Nuclear Information System (INIS)

Akashi, Masatsune; Kawamoto, Teruaki

1978-01-01

The effect of molybdenum addition on the SCC susceptibility of sensitized stainless steel in oxygenated high temperature water has been studied through the creviced bent beam SCC test (CBB test) and A262E intergranular corrosion test. The molybdenum addition improved the SCC susceptibility of sensitized stainless steels in oxygenated high temperature water not only by delaying the sensitization at lower temperatures but also by increasing the material resistance to the SCC under a given degree of sensitization. These laboratory test results reveal that the molybdenum addition is quite beneficial for improving the SCC susceptibility of stainless steel pipe weld joints in boiling water reactor environment. (auth.)

The clinical significance of follow up SCC levels in patients with recurrent squamous cell carcinoma of the cervix

International Nuclear Information System (INIS)

Choi, Young Min; Park, Sung Kwang; Cho, Heung Lae; Lee, Kyoung Bok; Kim, Ki Tae; Kim, Ju Ree; Sohn, Seung Chang

2002-01-01

To investigate the clinical usefulness of a follow-up examination using serum squamous cell carcinoma antigen (SCC) for the early detection of recurrence in patients treated for cervical squamous cell carcinoma. 20 patients who were treated for recurrent cervical squamous cell carcinoma between 1997 and 1998, who had experienced a complete remission after radiotherapy and who underwent an SCC test around the time when recurrence was detected, were included in this study. The levels of SCC were measured from the serum of the patients by immunoassay and values less than 2 ng/mL were regarded as normal. The sensitivity of the SCC test for use in the detection of recurrence, the association between the SCC values and the recurrence patterns and the tumor size and stage, and the temporal relation between the SCC increment and recurrence detection were evaluated. The SCC values were above normal in 17 out of 20 patients, so the sensitivity of the SCC test for the detection of recurrence was 85%, and the mean and median of the SCC values were 15.2 and 9.5 ng/mL, respectively. No differences were observed in the SCC values according to the recurrence sites. For 11 patients, the SCC values were measured over a pero id of 6 months before recurrence was detected, and the mean and median values were 13.6 and 3.6 ng/mL, respectively. The SCC values of 7 patients were higher than the normal range, and the SCC values of the other 4 patients were normal but 3 among them were above 1.5 ng/mL. At the time of diagnosis, the SCC valuess were measured for 16 of the 20 recurrent patients, and the SCC values of the patients with a bulky tumor (≥ 4 cm) or who were in stage IIb or III were higher than those of the patients with a non-bulky tumor or who were in stage Ib or IIa. The SCC test is thought to be useful for the early detection of recurrence during the follow up period in patients treated for cervical squamous cell carcinoma. When an effective salvage treatment is developed in

Influence of startup oxidizing transients of IGA/SCC in PWR steam generators

International Nuclear Information System (INIS)

Gorman, J.A.; McIlree, A.R.; Gaudreau, T.; Bjornkvist, L.; Andersson, P.-O.

1998-01-01

There is a considerable amount of evidence oxidizing conditions during and following startups are an important factor in the intergranular corrosion/stress corrosion cracking (IGA/SCC) of mill annealed alloy 600 steam generator tubes. This evidence includes plant data that indicate that the growth of IGA/SCC correlates better in some cases with numbers of startups than with time at power, laboratory tests in several plausible crevice environments that show that small amounts of copper oxides accelerate the rate of IGA/SCC, laboratory tests that show that elevating the electrochemical potential (ECP) increases the rates of IGA/SCC in many chemical environments, and laboratory tests that show that copper oxides, hematite, and other oxidized corrosion products can raise the ECP of several solution chemistries into aggressive ranges. Some preliminary data also exist that show that some amounts of oxidized species are produced during typical layup and startup conditions, but data for the subsequent reduction of these oxides are largely lacking. The purpose of this paper is to review the available evidence, to arrive at conclusions regarding the probable importance of oxidizing conditions during startup on occurrence of IGA/SCC, and to identify needed research to better quantify the situation. (author)

Multi-scale analysis of deformation behavior at SCC crack tip (3) (Contract research)

International Nuclear Information System (INIS)

Kaji, Yoshiyuki; Miwa, Yukio; Tsukada, Takashi; Hayakawa, Masao; Nagashima, Nobuo

2008-08-01

In recent years, incidents of the stress corrosion cracking (SCC) were frequently reported that occurred to the various components of domestic boiling water reactors (BWR), and the cause investigation and measure become the present important issue. By the Japan nuclear energy safety organization (JNES), a research project on the intergranular SCC (IGSCC) in nuclear grade stainless steels (henceforth, IGSCC project) is under enforcement from a point of view to secure safety and reliability of BWR, and SCC growth data of low carbon stainless steels are being accumulated for the weld part or the work-hardened region adjacent to the weld metal. In the project, it has been an important subject to guarantee the validity of accumulated SCC data. At a crack tip of SCC in compact tension (CT) type specimen used for the SCC propagation test, a macroscopic plastic region is formed where heterogeneity of microstructure developed by microscopic sliding and dislocations is observed. However, there is little quantitative information on the plastic region, and therefore, to assess the data of macroscopic SCC growth rate and the validity of propagation test method, it is essentially required to investigate the plastic region at the crack tip in detail from a microscopic viewpoint. This report describes a result of the research conducted by the Japan Atomic Energy Agency and the National Institute for Materials Science under contract with JNES that was concerned with a multi-scale analysis of plastic deformation behavior at the crack tip of SCC. The research was carried out to evaluate the validity of the SCC growth data acquired in the IGSCC project based on a mechanistic understanding of SCC. For the purpose, in this research, analyses of the plastic deformation behavior and microstructure around the crack tip were performed in a nano-order scale. The hardness measured in nano, meso and macro scales was employed as a common index of the strength, and the essential data necessary

Elucidating the iodine stress corrosion cracking (SCC) process for zircaloy tubing

International Nuclear Information System (INIS)

Nagai, M.; Shimada, S.; Nishimura, S.; Amano, K.

1984-01-01

Several experimental investigations were made to enhance understanding of the iodine stress corrosion cracking (SCC) process for Zircaloy: (1) oxide penetration process, (2) crack initiation process, and (3) crack propagation process. Concerning the effect of the oxide layer produced by conventional steam-autoclaving, no significant difference was found between results for autoclaved and as-pickled samples. Tests with 15 species of metal iodides revealed that only those metal iodides which react thermodynamically with zirconium to produce zirconium tetraiodide (ZrI 4 ) caused SCC of Zircaloy. Detailed SEM examinations were made on the SCC fracture surface of irradiated specimens. The crack propagation rate was expressed with a da/dt=C Ksup(n) type equation by combining results of tests and calculations with a finite element method. (author)

Effects of temperature on SCC propagation in high temperature water injected with hydrogen peroxide

International Nuclear Information System (INIS)

Nakano, Junichi; Sato, Tomonori; Kato, Chiaki; Yoshiyuki, Kaji; Yamamoto, Masahiro; Tsukada, Takashi

2012-09-01

film were performed on the fracture surface. In addition, to estimate the environmental situation in crack by prediction of oxide formation, a thermal equilibrium calculation was performed using a computer code for simulating aqueous-based chemical systems. Tensile tests were also carried out at 453 and 561 K in air to evaluate an effect of temperature on mechanical properties. Conclusions obtained in this study are summarized as follows; (1) Specimen exposed to 100 ppb H 2 O 2 at 453 K and 8 ppm O 2 at 561 K showed a steady SCC propagation behaviour. In 100 ppb H 2 O 2 at 561 K, however, an intergranular type SCC (IGSCC) was observed only small portion of area near the side groove of specimen. Effects of H 2 O 2 on SCC growth behaviour appeared stronger at lower temperature due to a reduction of the thermal decomposition of H 2 O 2 . (2) In 100 ppb H 2 O 2 at 453 K and 8 ppm O 2 at 561 K, a single phase oxide of Fe 3 O 4 was observed near the crack tip. In 100 ppb H 2 O 2 at 561 K, however, mixture of NiFe 2 O 4 , Fe 3 O 4 and Fe 2 O 3 was distributed on the surface of side groove and the crack mouth. When SCC propagated steadily, Fe 3 O 4 was produced near the crack tip. (3) Thermal equilibrium calculation for oxide formation at 561 and 453 K showed that a domain of stable Fe 2 O 3 spreads toward high pH region with decreasing in temperature which seemed to be due to production of Fe 3+ and OH - by thermal decomposition of H 2 O 2 . (authors)

Determination of I-SCC crack propagation rate of zircaloy-4

International Nuclear Information System (INIS)

Woo-Seog, Ryu

2002-01-01

Threshold stress intensity (K ISCC ) and propagation rate of iodine-induced SCC in recrystallized and stress-relieved Zircaloy-4 were determined using a DCPD method. Dynamic system flowing Ar gas through iodine chamber at 60 deg C provided a constant iodine pressure of 1000 Pa during test. The SCC curves of crack velocity vs. stress intensity showed the typical SCC curves that are composed of stages I, II and III. The threshold K ISCC at 350 deg C was about 9 and 9.5 MPa √m for the stress- relieved Zircaloy-4 and the recrystallized Zircaloy-4, respectively. The plateau velocity in the stage II at 350 deg C was 4-8x 10 -4 mm/sec in the range of 20-40 MPa√m. In comparison with recrystallized Zircaloy-4, stress-relieved Zircaloy-4 had a lower threshold stress intensity factor and a little higher SCC velocity, indicating that SRA Zircaloy-4 was more sensitive to SCC in respect of velocity. The fracture mode in recrystallized Zircaloy was mostly a transgranular fracture with river pattern. An intergranular mode and the flutting were scarcely observed. (author)

Computational modelling of SCC flow

DEFF Research Database (Denmark)

Geiker, Mette Rica; Thrane, Lars Nyholm; Szabo, Peter

2005-01-01

To benefit from the full potential of self-compacting concrete (SCC) prediction tools are needed for the form filling of SCC. Such tools should take into account the properties of the concrete, the shape and size of the structural element, the position of rebars, and the casting technique. Examples...

SCC testing of steam generator tubes repaired by welded sleeves

International Nuclear Information System (INIS)

Pierson, E.; Stubbe, J.

1993-01-01

One way to repair steam generator tubing is to introduce a sleeve inside the tube so that it spans the corroded area and to seal it at both ends. This technique has been studied at Laborelec with a particular attention paid to the occurrence of new SCC cracks at the upper joint. Tube segments coming from the same lot of mill annealed alloy 600 were sent to six manufacturers to be sleeved by their own procedure (including TIG, laser or kinetic welding, followed or not by a stress relief heat treatment), and then tested at Laborelecin 10% NaOH at 350 degrees C. The tests were performed with and without differential pressure i.e. in capsules (Δ = 9 and 19 MPa) and in autoclave (Δp = 0). Nearly all the not stress relieved mock-ups developed through cracks in several hundred hours in auto-clave. The cracks were circumferential and situated near the weld. At 9 and 19 MPa, the time to failure decreased and longitudinal cracks appeared near the weld and at the transition zone of expanded areas. Cracks were never observed in the alloy 690 sleeve, except in the weld bead. Reference capsules (roll expaned tubes) made of the same lot of alloy 600 were tested in the same environment

Evaluation of SCC test methods for Inconel 600 in low temperature aqueous solutions

International Nuclear Information System (INIS)

Newman, R.C.; Roberge, R.; Bandy, R.

1982-04-01

In late 1981, widespread leakage was encountered in Alloy 600 steam-generator tubing at the Three Mile Island Unit 1 nuclear power plant. The phenomenon was identified as low-temperature intergranular stress-corrosion cracking (SCC) initiated from the inner surfaces of the tubes exposed to the primary coolant. A testing program was initiated to examine the material and environmental factors relevant to these failures, which were found to be associated with sensitization of the material and contamination of the coolant by air and sodium thiosulfate. The test solutions contained 1.3% boric acid with various additions of sulfur compounds and lithium hydroxide. Constant extension rate testing was used as the primary tool to examine environmental effects such as the inhibition of cracking by lithium hydroxide. Important effects of crack-initiation frequency on the specimen potential (and therefore crack velocity) are demonstrated

A quantitative prediction model of SCC rate for nuclear structure materials in high temperature water based on crack tip creep strain rate

International Nuclear Information System (INIS)

Yang, F.Q.; Xue, H.; Zhao, L.Y.; Fang, X.R.

2014-01-01

Highlights: • Creep is considered to be the primary mechanical factor of crack tip film degradation. • The prediction model of SCC rate is based on crack tip creep strain rate. • The SCC rate calculated at the secondary stage of creep is recommended. • The effect of stress intensity factor on SCC growth rate is discussed. - Abstract: The quantitative prediction of stress corrosion cracking (SCC) of structure materials is essential in safety assessment of nuclear power plants. A new quantitative prediction model is proposed by combining the Ford–Andresen model, a crack tip creep model and an elastic–plastic finite element method. The creep at the crack tip is considered to be the primary mechanical factor of protective film degradation, and the creep strain rate at the crack tip is suggested as primary mechanical factor in predicting the SCC rate. The SCC rates at secondary stage of creep are recommended when using the approach introduced in this study to predict the SCC rates of materials in high temperature water. The proposed approach can be used to understand the SCC crack growth in structural materials of light water reactors

Durability Indicators Comparison for SCC and CC in Tropical Coastal Environments.

Science.gov (United States)

Calado, Carlos; Camões, Aires; Monteiro, Eliana; Helene, Paulo; Barkokébas, Béda

2015-03-27

Self-compacting concrete (SCC) demands more studies of durability at higher temperatures when subjected to more aggressive environments in comparison to the conventional vibrated concrete (CC). This work aims at presenting results of durability indicators of SCC and CC, having the same water/binder relations and constituents. The applied methodologies were electrical resistivity, diffusion of chloride ions and accelerated carbonation experiments, among others, such as microstructure study, scanning electron microscope and microtomography experiments. The tests were performed in a research laboratory and at a construction site of the Pernambuco Arena. The obtained results shows that the SCC presents an average electrical resistivity 11.4% higher than CC; the average chloride ions diffusion was 63.3% of the CC; the average accelerated carbonation penetration was 45.8% of the CC; and the average open porosity was 55.6% of the CC. As the results demonstrated, the SCC can be more durable than CC, which contributes to elucidate the aspects related to its durability and consequent prolonged life cycle.

Effect of surface grinding on chloride induced SCC of 304L

Energy Technology Data Exchange (ETDEWEB)

Zhou, Nian, E-mail: nzh@du.se [Department of Material Science, Dalarna University, SE-79188 Falun (Sweden); KTH, SE-10044 Stockholm (Sweden); Pettersson, Rachel [KTH, SE-10044 Stockholm (Sweden); Jernkontoret, SE-11187 Stockholm (Sweden); Lin Peng, Ru [Department of Management and Engineering, Linköping University, SE-58183 Linköping (Sweden); Schönning, Mikael [Corrosion Department, Avesta Research Centre – Outokumpu Stainless AB, SE-774 22 Avesta (Sweden)

2016-03-21

The effect of surface grinding on the stress corrosion cracking (SCC) behavior of 304L austenitic stainless steel in boiling magnesium chloride has been investigated. SCC tests were conducted both without external loading and with varied levels of four-point bend loading for as-delivered material and for specimens which had been ground parallel or perpendicular to the loading direction. Residual stresses due to the grinding operation were measured using the X-ray diffraction technique. In addition, surface stress measurements under applied load were performed before exposure to evaluate the deviation between actual applied loading and calculated values according to ASTM G39. Micro-cracks initiated by a high level of tensile residual stress in the surface layer were observed for all the ground specimens but not those in the as-delivered condition. Grinding along the loading direction increased the susceptibility to chloride induced SCC; while grinding perpendicular to the loading direction improved SCC resistance. Surface tensile residual stresses were largely relieved after the initiation of cracks.

Effect of surface grinding on chloride induced SCC of 304L

International Nuclear Information System (INIS)

Zhou, Nian; Pettersson, Rachel; Lin Peng, Ru; Schönning, Mikael

2016-01-01

The effect of surface grinding on the stress corrosion cracking (SCC) behavior of 304L austenitic stainless steel in boiling magnesium chloride has been investigated. SCC tests were conducted both without external loading and with varied levels of four-point bend loading for as-delivered material and for specimens which had been ground parallel or perpendicular to the loading direction. Residual stresses due to the grinding operation were measured using the X-ray diffraction technique. In addition, surface stress measurements under applied load were performed before exposure to evaluate the deviation between actual applied loading and calculated values according to ASTM G39. Micro-cracks initiated by a high level of tensile residual stress in the surface layer were observed for all the ground specimens but not those in the as-delivered condition. Grinding along the loading direction increased the susceptibility to chloride induced SCC; while grinding perpendicular to the loading direction improved SCC resistance. Surface tensile residual stresses were largely relieved after the initiation of cracks.

SCC of cold-worked austenitic stainless steels exposed to PWR primary water conditions: susceptibility to initiation

International Nuclear Information System (INIS)

Herms, E.; Raquet, O.; Sejourne, L.; Vaillant, F.

2009-01-01

Heavily cold-worked austenitic stainless steels (AISI 304L and 316L types) could be significantly susceptible to Stress Corrosion Cracking (SCC) when exposed to PWR nominal primary water conditions even in absence of any pollutants. Susceptibility to SCC was shown to be related with some conditions such as initial hardness, procedure of cold-work or dynamic straining. A dedicated program devoted to better understand the initiation stage on CW austenitic stainless steels in PWR water is presented. Initiation is studied thanks to SCC test conditions leading to an intergranular cracking propagation mode on a CW austenitic stainless steel which is the mode generally reported after field experience. SCC tests are carried out in typical primary water conditions (composition 1000 ppm B and 2 ppm Li) and for temperature in the range 290 - 340 C. Material selected is 316L cold-worked essentially by rolling (reduction in thickness of 40%). Initiation tests are carried out under various stress levels with the aim to investigate the evolution of the initiation period versus the value of applied stress. SCC tests are performed on cylindrical notched specimens in order to increase the applied stress and allow accelerated testing without modify the exposure conditions to strictly nominal hydrogenated PWR water. Respective influences of cyclic/dynamic conditions on SCC initiation are presented and discussed. Dedicated interrupted tests help to investigate the behaviour of the crack initiation process. These SCC tests have shown that crack initiation could be obtained after a very short time under dynamic loading conditions on heavily pre-strained austenitic stainless steels. Actual results show that the most limiting stage of the cracking process on CW 316L seems to be the transition from slow transgranular propagation of surface initiated cracks to intergranular fast propagation through the thickness of the sample. The duration of this stage during crack initiation tests is

An Investigation of the Mechanism of IGA/SCC of Alloy 600 in Corrosion Accelerating Heated Crevice Environments - Topical Report Phase I 8/18/1999 - 8/31/2000

International Nuclear Information System (INIS)

Lumsden, Jesse

2000-01-01

The crevice formed by the tube/tube support plate (T/TSP) intersection in a pressurized water reactor (PWR) steam generator is a concentration site for nonvolatile impurities (referred to as hideout) in the steam generator water. The restricted mass transport in the small crevice volume prevents the species, which concentrate by a thermal/hydraulic mechanism during the generation of steam, from quickly dispersing into the bulk water. The presence of a porous scale corrosion product on the surface of the tube and deposits of corrosion products in the crevice further restrict mass transport. The concentrated solutions and deposits in T/TSP crevices have been correlated with several forms of corrosion on the OD of steam generator tubes including intergranular attack/stress corrosion cracking (IGA/SCC), pitting, and wastage. The rate and type of corrosion are dependent on pH, specific anions, and the electrochemical potential. Careful water chemistry control and other remedial measures have essentially stopped all forms of secondary side corrosion except IGA/SCC. Crevice chemistries in an operating steam generator cannot be measured directly because of their inaccessibility. In practice, computer codes (MULTEQ, Molar Ratio Index, etc.) based upon hypothesized chemical reactions and thermal hydraulic mechanisms are used to predict crevice chemistry. The Rockwell program provides an experimental base to benchmark crevice chemistry models and to benchmark crevice chemistry control measures designed to mitigate IGA/SCC. The objective of this program is to develop an understanding of the corrosion accelerating mechanisms, particularly IGA/SCC, in steam generator crevices. The important variables will be identified, including the relationship between bulk water chemistry and corrosion accelerating chemistries in a crevice. An important result will be the identification of water chemistry control measures needed to mitigate secondary side IGA/SCC in steam generator tubes. The

An application of the recrystallization method for the observation of plastic strain distribution around SCC cracks in sensitized SUS 304 stainless steels

International Nuclear Information System (INIS)

Tokiwai, Moriyasu

1981-01-01

Various types of stress corrosion cracking (SCC) testing methods have been developed since the SCC was discovered in type 304 stainless steel of BWR cooling pipes. With regard to the countermeasures for SCC, it is essential to evaluate the SCC susceptibility under the simulated or accelerated testing conditions. Among various acceleration SCC tests, the slow strain rate technique (SSRT) test has been used most widely. The SCC susceptibility, in almost cases, has been evaluated not on the base of the crack behavior but of the reduction of stress or strain under the corrosive environment. It is well known that the intensively deformed zone (plastic zone) is formed at the crack tip in fatigue and creep phenomena, but such plastic zone related with the resistance of crack extention has not been studied in SCC phenomenon. The objective of this study is to confirm the existence of the plastic zone at tips of SCC cracks by the application of the recrystallization method. The shape and the distribution of the plastic zone was measured by use of optical and scanning electron microscope in sensitized specimens SSRT tested in high temperature water containing various concentrations of dissolved oxygen. Results obtained are discussed in relation to the susceptibility of SCC. (author)

Effect of dissolved oxygen on SCC of LP turbine steel

International Nuclear Information System (INIS)

Maeng, W. Y.; Lee, J. H.; Kim, W. C.

2002-01-01

Slow Strain Rate Tests (SSRT) were carried out to investigate the effect of dissolved oxygen on Stress Corrosion Cracking (SCC) susceptibility of 3.5NiCrMoV steels used in discs of Low-Pressure (LP) steam turbines in electric power generating plants. The influence of dissolved oxygen on cracking in water was studied; for this purpose, specimens were strained to fracture at 150 .deg. C in water environments with various amounts of dissolved oxygen. The maximum elongation of the turbine steel decreased with increasing dissolved oxygen. Dissolved oxygen significantly affected the SCC susceptibility of turbine steel in water. The increase of the SCC susceptibility of the turbine steel in a higher dissolved oxygen environment is due to the non protectiveness of the oxide layer of the turbine steel surface and the increase of corrosion current

Application of tumor markers SCC-Ag, CEA, and TPA in patients with cervical precancerous lesions.

Science.gov (United States)

Farzaneh, Farah; Shahghassempour, Shapour; Noshine, Bahram; Arab, Maliheh; Yaseri, Mehdi; Rafizadeh, Mitra; Alizadeh, Kamyab

2014-01-01

To determine the potential clinical utility of tumor markers CEA, TPA, and SCC-Ag for early detection of cervical precancerous lesions. A case-control study was carried out on 120 women (46 patients with histologically confirmed cervical precancerous lesions and 74 healthy controls). The significance of serum selected tumor markers in early detection of cervical intraepithelial neoplasia (CIN) were assessed. Of the case group, the rates of CIN I, II, III, was 69.6%, 23.9%, and 6.5%, respectively. According to the manufacturer's cut-off values of 2 ng/ml, 5 ng/ml, and 70 U/ml for SCC-Ag, CEA and TPA tests, in that order, SCC-Ag test had a sensitivity of 13%, but CEA and TPA tests could not distinguish between case and control groups. The diagnostic sensitivities were highest at cut-off values of 0.55 ng/ml for SCC-Ag, 2.6 ng/ ml for CEA, and 25.5 U/ml for TPA which were 93%, 61%, and 50%, respectively. However, the area under the receiver operating characteristic curve was the largest for SCC-Ag (0.95 vs. 0.61 and 0.60 for CEA and TPA, respectively). Moreover, there was a highly significant direct correlation between SCC-Ag concentration and the degree of cervical precancerous lesions (r=0.847, ptumor marker in Iranian patients with CIN and it needs to be more evaluated by studies with larger populationa.

Rehabilitation of the gas pipeline that had a rupture in service caused by SCC (Stress Corrosion C raking); Rehabilitacion al servicio de un gasoducto que ha sufrido una ruptura en servicio por SCC

Energy Technology Data Exchange (ETDEWEB)

Silva, Fernando; Carzoglio, Eduardo; Hryciuk, Pedro [TGN - Transportadora de Gas del Norte S.A. (Argentina). Depto. de Integridad

2003-07-01

TGN had a rupture in service on Gasoducto Troncal Norte. After initial evaluation of the causes of the rupture it was concluded that it had been caused by Stress Corrosion Cracking (SCC). Subsequent investigation in the area of the rupture revealed that colonies of cracks, typical of SCC were found in pipes located near the rupture. In order to put back in service the pipeline in a safety condition, SCC mitigation activities were performed. A decision was made to conduct a hydro test along approximately 30 kilometers of pipe. The stages of the works, the problems faced and the solutions found are dealt with, as well as the conclusions reached upon completion of the works which allowed a better understanding of SCC phenomenon. The methodology for the identification of those areas susceptible to SCC is also described. (author)

Stress Corrosion Cracking of Pipeline Steels in Fuel Grade Ethanol and Blends - Study to Evaluate Alternate Standard Tests and Phenomenological Understanding of SCC

Science.gov (United States)

2011-10-30

Main aim of this project was to evaluate alternate standard test methods for stress corrosion cracking (SCC) and compare them with the results from slow strain rate test (SSRT) results under equivalent environmental conditions. Other important aim of...

SCC growth behavior of stainless steel weld heat-affected zone in hydrogenated high temperature water

International Nuclear Information System (INIS)

Yamada, Takuyo; Terachi, Takumi; Miyamoto, Tomoki; Arioka, Koji

2010-01-01

It is known that the SCC growth rate of stainless steels in high-temperature water is accelerated by cold-work (CW). The weld heat-affected-zone (HAZ) of stainless steels is also deformed by weld shrinkage. However, only little have been reported on the SCC growth of weld HAZ of SUS316 and SUS304 in hydrogenated high-temperature water. Thus, in this present study, SCC growth experiments were performed using weld HAZ of stainless steels, especially to obtain data on the dependence of SCC growth on (1) temperature and (2) hardness in hydrogenated water at temperatures from 250degC to 340degC. And then, the SCC growth behaviors were compared between weld HAZ and CW stainless steels. The following results have been obtained. Significant SCC growth were observed in weld HAZ (SUS316 and SUS304) in hydrogenated water at 320degC. The SCC growth rates of the HAZ are similar to that of 10% CW non-sensitized SUS316, in accordance with that the hardness of weld HAZ is also similar to that of 10% CW SUS316. Temperature dependency of SCC growth of weld HAZ (SUS316 and SUS304) is also similar to that of 10% CW non-sensitized SUS316. That is, no significant SCC were observed in the weld HAZ (SUS316 and SUS304) in hydrogenated water at 340degC. This suggests that SCC growth behaviors of weld HAZ and CW stainless steels are similar and correlated with the hardness or yield strength of the materials, at least in non-sensitized regions. And the similar temperature dependence between the HAZ and CW stainless steels suggests that the SCC growth behaviors are also attributed to the common mechanism. (author)

An Investigation of the Mechanism of IGA/SCC of Alloy 600 in Corrosion Accelerating Heated Crevice Environments - Topical Report Phase I 8/18/1999 - 8/31/2000; TOPICAL

International Nuclear Information System (INIS)

Dr. Jesse Lumsden

2000-01-01

The crevice formed by the tube/tube support plate (T/TSP) intersection in a pressurized water reactor (PWR) steam generator is a concentration site for nonvolatile impurities (referred to as hideout) in the steam generator water. The restricted mass transport in the small crevice volume prevents the species, which concentrate by a thermal/hydraulic mechanism during the generation of steam, from quickly dispersing into the bulk water. The presence of a porous scale corrosion product on the surface of the tube and deposits of corrosion products in the crevice further restrict mass transport. The concentrated solutions and deposits in T/TSP crevices have been correlated with several forms of corrosion on the OD of steam generator tubes including intergranular attack/stress corrosion cracking (IGA/SCC), pitting, and wastage. The rate and type of corrosion are dependent on pH, specific anions, and the electrochemical potential. Careful water chemistry control and other remedial measures have essentially stopped all forms of secondary side corrosion except IGA/SCC. Crevice chemistries in an operating steam generator cannot be measured directly because of their inaccessibility. In practice, computer codes (MULTEQ, Molar Ratio Index, etc.) based upon hypothesized chemical reactions and thermal hydraulic mechanisms are used to predict crevice chemistry. The Rockwell program provides an experimental base to benchmark crevice chemistry models and to benchmark crevice chemistry control measures designed to mitigate IGA/SCC. The objective of this program is to develop an understanding of the corrosion accelerating mechanisms, particularly IGA/SCC, in steam generator crevices. The important variables will be identified, including the relationship between bulk water chemistry and corrosion accelerating chemistries in a crevice. An important result will be the identification of water chemistry control measures needed to mitigate secondary side IGA/SCC in steam generator tubes. The

Durability Indicators Comparison for SCC and CC in Tropical Coastal Environments

Directory of Open Access Journals (Sweden)

Carlos Calado

2015-03-01

Full Text Available Self-compacting concrete (SCC demands more studies of durability at higher temperatures when subjected to more aggressive environments in comparison to the conventional vibrated concrete (CC. This work aims at presenting results of durability indicators of SCC and CC, having the same water/binder relations and constituents. The applied methodologies were electrical resistivity, diffusion of chloride ions and accelerated carbonation experiments, among others, such as microstructure study, scanning electron microscope and microtomography experiments. The tests were performed in a research laboratory and at a construction site of the Pernambuco Arena. The obtained results shows that the SCC presents an average electrical resistivity 11.4% higher than CC; the average chloride ions diffusion was 63.3% of the CC; the average accelerated carbonation penetration was 45.8% of the CC; and the average open porosity was 55.6% of the CC. As the results demonstrated, the SCC can be more durable than CC, which contributes to elucidate the aspects related to its durability and consequent prolonged life cycle.

A Review of Root Causes of SCC Phenomena in BWR/RBMK: An Overview of Radiation-Induced Long Cell Action Relevant to SCC

International Nuclear Information System (INIS)

Genn Saji

2004-01-01

The author suggests a new hypothetical mechanism: radiation-induced 'long cell action' may cause electrolytic corrosion. In this mechanism, SCC (stress corrosion cracking) results from auto-catalytic growth of cracks in crevice water chemistry that is kept acidic by a combination of hydration of cations released from crack tips. The acidic chemistry is maintained by radiation-induced 'long cell action' in pits which are maintained by a trans-passive corrosion process under a stress field. The pivotal point of the thesis is 'long cell action' which appears not to have been investigated in the nuclear community. It is because the reactor water used in BWR/RBMK systems has a very low electrical conductivity. For 'long cell action' to take place, there must be an unknown ion transport mechanism. One potential mechanism can be the high flow rate of the reactor water, carrying ionic species from the anode to the cathode. The other is the effective removal of ferrous ions by deposition as crud, which enhanced by the decomposition of H 2 O 2 . There are also some surprising similarities between SCC in the reactor systems and the basic mechanism of underground corrosion by long cell action. In this mechanism, the 'long cell action' is induced by a difference in availability of oxygen inside the soil. Conduction of electrons through an electric conductor over a long distance plays a significant role as they are released by dissolution of metallic ions and sucked up from the metal surface. (author)

Assessment of and proposal for a mechanistic interpretation of the SCC of high nickel alloys in lead-containing environments

International Nuclear Information System (INIS)

Staehle, R.W.

2002-01-01

The SCC of Alloys 600 and 690 in lead-containing solutions, 'lead stress corrosion cracking' (PbSCC) is quite aggressive on tubing in conditions of operation of steam generators (SG) in pressurized water reactors (PWR). Lead dissolved in water can produce PbSCC at concentrations of Pb as low as 0.1 ppm in these alloys. PbSCC is perhaps the most generally aggressive of the environmental species that occur in SGs. This discussion considers the occurrence of Pb in SGs and the PbSCC that can result. The dependencies of PbSCC on the variables of pH, potential, species, alloy composition, alloy structure, temperature and stress are reviewed. Also, important features of the mechanism of PbSCC are assessed. The most significant question related to PbSCC is why more is not occurring in view of the low thresholds for the PbSCC and the ubiquity of the Pb. While there are usually no common specific sources for Pb in most secondary systems, Pb concentrates on surfaces of tubing efficiently over long times. Regardless, it appears that extensive PbSCC does not occur because it is immobilized by forming stable compounds with other species such as sulfur, carbon, phosphorous and silica. Pb is also immobilized by forming stable adsorbed states with oxides such as magnetite and hematite. The possibility of releasing Pb to produce PbSCC increases as water chemistry produces more pure systems and as chemical cleaning is used. Contrary to the common assumption that PbSCC is TGSCC, that of Alloy 600MA is generally IGSCC; only the sensitized (SN), stress relieved (SR) and thermally treated (TT) conditions of Alloys 600 and 690 sustain TGSCC in Pb-containing solutions. In view of the prevailing IGSCC produced by Pb in MA materials, the possibility of all IGSCC in SGs being due to Pb should be considered where crevice environments are in the nominally neutral range. TGSCC that is observed in SGs can be produced by other, although not widely appreciated, environments. The mechanism of PbSCC

Magnesium alloys as body implants: fracture mechanism under dynamic and static loadings in a physiological environment.

Science.gov (United States)

Choudhary, Lokesh; Raman, R K Singh

2012-02-01

It is essential that a metallic implant material possesses adequate resistance to cracking/fracture under the synergistic action of a corrosive physiological environment and mechanical loading (i.e. stress corrosion cracking (SCC)), before the implant can be put to actual use. This paper presents a critique of the fundamental issues with an assessment of SCC of a rapidly corroding material such as magnesium alloys, and describes an investigation into the mechanism of SCC of a magnesium alloy in a physiological environment. The SCC susceptibility of the alloy in a simulated human body fluid was established by slow strain rate tensile (SSRT) testing using smooth specimens under different electrochemical conditions for understanding the mechanism of SCC. However, to assess the life of the implant devices that often possess fine micro-cracks, SCC susceptibility of notched specimens was investigated by circumferential notch tensile (CNT) testing. CNT tests also produced important design data, i.e. threshold stress intensity for SCC (KISCC) and SCC crack growth rate. Fractographic features of SCC were examined using scanning electron microscopy. The SSRT and CNT results, together with fractographic evidence, confirmed the SCC susceptibility of both smooth and notched specimens of a magnesium alloy in the physiological environment. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Effects of hydrogen during SCC of Al-5Mg alloys in NaCl 30 g/l environment: experimental study and numerical simulations

International Nuclear Information System (INIS)

Tanguy, Dome

2001-01-01

After a presentation of the industrial context and of some knowledge about stress corrosion cracking (SCC) of 5xxx alloys (notably their sensitivity to intergranular dissolution in presence of the Al 3 Mg 2 phase in grain boundaries) and about other mechanisms intervening in SCC, this research thesis reports a characterization of intergranular precipitation in the alloys for which SCC and corrosion fatigue tests have been performed. Experimental results are reported and discussed (crack initiation and growth, growth rate, loading mode). The simulation of a model microstructure at the atomic scale is presented. It allows hydrogen trapping to be studied with respect to the presence of magnesium at the grain boundary. A numerical model of the Al-Mg system is developed to study the first stages of magnesium-rich intergranular precipitation. The next part reports the study of hydrogen intergranular trapping in Al-Mg by focusing on the Mg-H binding energy and on trapping occurring in the boundary. In conclusion, the author proposes a fracture mechanism at the atomic scale

Characterization of SCC crack tips and surface oxide layers in alloy 600

Energy Technology Data Exchange (ETDEWEB)

Fujii, Katsuhiko; Fukuya, Koji [Inst. of Nuclear Safety System Inc., Mihama, Fukui (Japan)

2002-09-01

In order to investigate the mechanism of primary water stress corrosion cracking (SCC), direct observation of microstructures of SCC crack tips and surface oxide layers in alloy 600 were carried out. A focused-ion beam (FIB) micro-processing technique was applied to prepare electron transparent foils including the crack tip and the surface oxide layer without any damage to those microstructures. Transmission electron microscopy and analysis were used to characterize the crack tips and surface oxide layers. Cr-rich oxides and a metal-Ni phase were identified in the crack tips and grain boundaries ahead of the crack tips independent of dissolved hydrogen concentrations. >From the fact that the Cr-rich oxides and metal-Ni phase were observed in the inner surface oxide layer, the same oxidation mechanism as the surface is proposed for the crack tip region and internal oxidation accompanying selective Cr oxidation is suggested as the mechanism. (author)

Improvement of life time of SCC in type 304 stainless steel by ultrasound irradiation

International Nuclear Information System (INIS)

Tokiwai, Moriyasu; Kimura, Hideo

1985-01-01

It is well known that the susceptibility to stress corrosion cracking (SCC) is controled by compressive stress such as shot-peening treatment. In this study, the effects of ultrasound irradiation to type 304 stainless upon SCC were investigated. The main findings are as follows; (1) Ultrasound irradiation produces the high level compressive stress on the surface of metals. This compressive stress was induced by the cavitation phenomenon. (2) In U-bent specimen, the initial tensile stress was mitigated and converted to compressive stress by ultrasound irradiation. (3) Type 304 stainless steel was subjected to SCC test using sodium thyosulfate solution. It was definitely demonstrated that the ultrasound irradiation was effective for the mitigation of SCC life time. (4) Ultrasound irradiation time was one of the most important factors in irradiation conditions. (author)

Iodine stress corrosion cracking (SCC) of unirradiated Zircaloy-4 tubing by means of internal gas pressurization, (1)

International Nuclear Information System (INIS)

Onchi, Takeo; Inoue, Tadashi

1982-01-01

The internal gas pressurization tests were conducted at 360 0 C, to examine the influence of iodine concentration on the iodine stress corrosion cracking (SCC) susceptibility of Zircaloy-4 tubing of 17 x 17 type PWR design. The iodine contents studied were ranging of 0.06 to 6 mg/cm 2 , corresponding to 30 from 0.3 mg/cm 3 . Applied hoop stress vs. time-to-failure relationships were obtained in argon gas with iodine, as well as without iodine, from the tests of maximum holding times up to 72 hrs. The relationships obtained were insensitive to iodine contents. The applied stress lowering in iodine atmosphere approached a threshold stress below which SCC failure did not occur within the holding time, but not in argon gas alone. The threshold stresses were approximately 25.5 kg/mm 2 (250 Mpa), independent on iodine concentrations. Based on fracture mechanics approach and fractographic analysis, an interpretation was made of those applied stress and time-to-failure relationships. (author)

Eco-SCC: From Theory to Practical Application

NARCIS (Netherlands)

Hüsken, G.; Brouwers, H.J.H.; Shui, Z.; Wu, S.; Yu, J.

2010-01-01

This paper presents the results of an experimental investigation on the application of self-compacting concrete (SCC) with reduced cement content and fine stone waste materials. Two SCC mixes containing stone waste material were designed for the application in a new formwork system developed for

Multi-scale analysis of deformation behavior at SCC crack tip (2). (Contract research)

International Nuclear Information System (INIS)

Kaji, Yoshiyuki; Miwa, Yukio; Tsukada, Takashi; Hayakawa, Masao; Nagashima, Nobuo

2007-03-01

This report describes a result of the research conducted by the Japan Atomic Energy Agency and the National Institute for Materials Science under contract with Japan Nuclear Energy Safety Organization (JNES) that was concerned with a multi-scale analysis of plastic deformation behavior at the crack tip of stress corrosion cracking (SCC). The research was carried out to evaluate the validity of the SCC growth data acquired in the intergranular SCC (IGSCC) project based on a mechanistic understanding of SCC. For the purpose, in this research, analyses of the plastic deformation behavior and microstructure around the crack tip were performed in a nano-order scale. The hardness measured in nano, meso and macro scales was employed as a common index of the strength, and the essential data necessary to understand the SCC propagation behavior were acquired and analyzed that are mainly a size of plastic deformation region and a microstructural information in the region, e.g. data of crystallografy, microscopic deformation and dislocations at the inside of grains and grain boundaries. In this year, we analyzed the state of plastic deformation region at the crack tip of IGSCC under various conditions and investigated relationship between crack growth behavior and stress intensity factor. Especially, we investigated in detail about two different hardened specimens used in the SCC growth tests in the IGSCC project. (J.P.N.)

Characterization of SCC crack tip and hydrogen distribution in alloy 600

Energy Technology Data Exchange (ETDEWEB)

Fujii, Katsuhiko; Nakajima, Nobuo; Fukuya, Koji [Institute of Nuclear Safety System Inc., Mihama, Fukui (Japan); Hatano, Yuji [Toyama Univ. (Japan)

2001-09-01

In order to identify the mechanism of primary water stress corrosion cracking (SCC), direct observations of SCC crack tip microstructure and hydrogen distribution in alloy 600 were carried out. A new technique has been developed to prepare electron transparent foils including the crack tip using focused-ion beam (FIB) micro-processing technique. Cr-rich oxide and metal-Ni phase were identified in the crack tip and grain boundary ahead of the crack. >From the fact that similar microstructure was observed in the surface oxide layer, it is suggested that the oxidation mechanism is identical at the crack tip region and the surface. It became clear that the crack tip region and the oxidized grain boundary don't work as strong trapping sites of solute hydrogen under unloaded condition, because a homogeneous hydrogen distribution around the crack tip region was detected by tritium microautoradiography. (author)

SCC with high volume of fly ash content

Directory of Open Access Journals (Sweden)

Bakhrakh Anton

2017-01-01

Full Text Available Self-compacting concrete is a very perspective building material. It provides great benefits during the construction of heavily reinforced buildings. SCC has outstanding properties such as high flowability, dense structure and high strength due to specific quality of aggregates, fillers, their proportion in mix, use of polycarboxylate-based superplasticizers. Main disadvantages of SCC are high price and the difficulty of obtaining a proper mix. Use of fillers, such as fly ash type F, is a way to make SCC cheaper by replacing part of cement. Fly ash also provides some technological and operating advantages. In this paper the influence of high volume (60% from cement fly ash type F on the properties of concrete mixture and hardened concrete is investigated. The result of the work shows the possibility of reduction the cost of SCC using ordinary fillers and high amount of fly ash. The investigated SCC has low speed of hardening (7-day compressive strength at the range of 41.8 MPa and high volume of entrained air content (3.5%.

The Scc2/Scc4 complex acts in sister chromatid cohesion and transcriptional regulation by maintaining nucleosome-free regions

Science.gov (United States)

Lopez-Serra, Lidia; Kelly, Gavin; Patel, Harshil; Stewart, Aengus; Uhlmann, Frank

2014-01-01

The cohesin complex is at the heart of many chromosomal activities, including sister chromatid cohesion and transcriptional regulation1-3. Cohesin loading onto chromosomes depends on the Scc2/Scc4 cohesin loader complex4-6, but the chromatin features that form cohesin loading sites remain poorly understood. Here, we show that the RSC chromatin remodeling complex recruits budding yeast Scc2/Scc4 to broad nucleosome-free regions, that the cohesin loader itself helps to maintain. Consequently, inactivation of the cohesin loader or RSC complex have similar effects on nucleosome positioning, gene expression and sister chromatid cohesion. These results reveal an intimate link between local chromatin structure and higher order chromosome architecture. Our findings pertain to the similarities between two severe human disorders, Cornelia de Lange syndrome, caused by mutations in the human cohesin loader, and Coffin-Siris syndrome, resulting from mutations in human RSC complex components7-9. Both could arise from gene misregulation due to related changes in the nucleosome landscape. PMID:25173104

IGA/SCC propagation rate measurements on alloy 600 steam generator tubing using a side stream model boiler

International Nuclear Information System (INIS)

Takamatsu, H.; Matsueda, K.; Matsunaga, T.; Kitera, T.; Arioka, K.; Tsuruta, T.; Okamoto, S.

1993-01-01

IGA/SCC crack propagation rate measurements using various types of IGA/SCC predefected ALloy 600 tubing were tested in model boilers, a side stream model boiler at Ohi Unit 1 and similar model boilers in the laboratory. Types of IGA/SCC predefects introduced from the outside of the tubing were as follows. (1) Actual IGA/SCC predefect introduced by high temperature caustic environments; (2) Longitudinal predefect by electrodischarge machining (EDM) method, and then crack tip fatigue was introduced to serve as the marker on the fractured surface (EDM slit + fatigue). IGA/SCC crack propagation rate was measured after the destructive examination by Cr concentration profile on fracture surface for (1), and observation of intergranular fractured surface propagated from the marked fatigue was employed for (2) and (3) after the model boiler tests. As for the water chemistry conditions, mainly AVT (high N 2 H 4 ) + boric acid (5-10ppm as B in SGs) treatment for both model boilers, and some of the tests for the model boiler in the laboratory employed AVT (high N 2 H 4 ) without boric acid. The results of IGA/SCC crack propagation rate measurements were compared with each other, and the three methods employed showed a good coincidence with the rate of ca. 1 x 10 -5 mm/Hr for AVT (high N 2 H 4 ) + boric acid treatment condition, in the case that crack tip boron intensity (B/O value by IMMA analysis) of more than 1 was observed

SCC crack propagation behavior in 316L weld metal under high temperature water

International Nuclear Information System (INIS)

Nakade, Katsuyuki; Hirasaki, Toshifumi; Suzuki, Shunichi; Takamori, Kenro; Kumagai, Katsuhiko; Tanaka, Yoshihiko; Umeoka, Kuniyoshi

2008-01-01

Intergranular stress corrosion cracking (SCC) of 316L weld metal is of concern to the BWR plants. PLR pipes in commercial BWR plants have shown SCC in almost HAZ area in high temperature water, whereas, SCC has been arrested around fusion boundary for long time in the actual PLR pipe. The SCC behavior could be characterized in terms of dendrite direction, which was defined as the angle between dendrite growth direction and macro-SCC direction. In this study, the relationship between dendrite growth direction and macro-SCC direction was clearly showed on the fracture surface. The relative large difference of SCC susceptibility of 316L HAZ and weld metal was observed on the fracture surface. In the case of 0 degree, SCC has rapidly propagated into the weld metal parallel to the dendrite structure. In the case of more than 30 degree SCC direction, SCC was arrested around fusion area, and 60 degree SCC was drastically arrested around the fusion area. The large inclined dendrite structure for SCC is highly resistant to SCC. (author)

Chl1 DNA helicase regulates Scc2 deposition specifically during DNA-replication in Saccharomyces cerevisiae.

Directory of Open Access Journals (Sweden)

Soumya Rudra

Full Text Available The conserved family of cohesin proteins that mediate sister chromatid cohesion requires Scc2, Scc4 for chromatin-association and Eco1/Ctf7 for conversion to a tethering competent state. A popular model, based on the notion that cohesins form huge ring-like structures, is that Scc2, Scc4 function is essential only during G1 such that sister chromatid cohesion results simply from DNA replisome passage through pre-loaded cohesin rings. In such a scenario, cohesin deposition during G1 is temporally uncoupled from Eco1-dependent establishment reactions that occur during S-phase. Chl1 DNA helicase (homolog of human ChlR1/DDX11 and BACH1/BRIP1/FANCJ helicases implicated in Fanconi anemia, breast and ovarian cancer and Warsaw Breakage Syndrome plays a critical role in sister chromatid cohesion, however, the mechanism through which Chl1 promotes cohesion remains poorly understood. Here, we report that Chl1 promotes Scc2 loading unto DNA such that both Scc2 and cohesin enrichment to chromatin are defective in chl1 mutant cells. The results further show that both Chl1 expression and chromatin-recruitment are tightly regulated through the cell cycle, peaking during S-phase. Importantly, kinetic ChIP studies reveals that Chl1 is required for Scc2 chromatin-association specifically during S-phase, but not during G1. Despite normal chromatin enrichment of both Scc2 and cohesin during G1, chl1 mutant cells exhibit severe chromosome segregation and cohesion defects--revealing that G1-loaded cohesins is insufficient to promote cohesion. Based on these findings, we propose a new model wherein S-phase cohesin loading occurs during DNA replication and in concert with both cohesion establishment and chromatin assembly reactions--challenging the notion that DNA replication fork navigates through or around pre-loaded cohesin rings.

Report D : self-consolidating concrete (SCC) for infrastructure elements - creep, shrinkage and abrasion resistance.

Science.gov (United States)

2012-08-01

Concrete specimens were fabricated for shrinkage, creep, and abrasion resistance : testing. Variations of self-consolidating concrete (SCC) and conventional concrete were : all tested. The results were compared to previous similar testing programs an...

Report E : self-consolidating concrete (SCC) for infrastructure elements - hardened mechanical properties and durability performance.

Science.gov (United States)

2012-08-01

Concrete is one of the most produced and utilized materials in the world. Due to : the labor intensive and time consuming nature of concrete construction, new and : innovative concrete mixes are being explored. Self-consolidating concrete (SCC) is on...

Mechanical and environmental effects on stress corrosion cracking of low carbon pipeline steel in a soil solution

International Nuclear Information System (INIS)

Contreras, A.; Hernández, S.L.; Orozco-Cruz, R.; Galvan-Martínez, R.

2012-01-01

Highlights: ► Mechanical and environmental effects on SCC of X52 steel were investigated. ► Slow strain rate tests (SSRT) were performed in a soil solution (NS4). ► Different levels of polarization potentials were applied to mitigating SCC. ► SSRT results indicate that X52 pipeline steel was susceptible to SCC. ► SCC susceptibility increase as the yielding and ultimate tensile stress increase. -- Abstract: Mechanical and environmental effects on stress corrosion cracking (SCC) susceptibility of X52 pipeline steel were investigated using slow strain rate tests (SSRT) performed in a glass autoclave containing a soil solution at strain rate of 1 × 10 −6 in./s at room temperature. Polarization potentials of −100, −200 and −400 mV referred to open circuit potential (OCP) was applied in order to establish the effectiveness of cathodic protection in mitigating SCC of X52 pipeline steel. Electrochemical impedance spectroscopy (EIS) tests and scanning electron microscopy (SEM) observations were done in order to analyze the SCC process. SSRT results indicate that X52 pipeline steel was susceptible to SCC. Susceptibility to SCC increase as the yielding stress (YS) and ultimate tensile stress (UTS) increase. The EIS results showed that the highest corrosion of the steel sample was obtained when the highest cathodic over potential was applied. SEM observations of these specimens showed a brittle type of fracture with transgranular appearance. The failure and SCC of X52 steel in soil solution was explained by hydrogen mechanism.

The manufacturing of Stress Corrosion Crack (SCC) on Inconel 600 tube

International Nuclear Information System (INIS)

Bae, Seunggi; Bak, Jaewoong; Kim, Seongcheol; Lee, Sangyul; Lee, Boyoung

2014-01-01

The Stress Corrosion Crack (SCC), taken a center stage in recently accidents about nuclear power plants, is one of the environmentally induced cracking occurred when a metallic structure under tensile stress is exposed to corrosive environment. In this study, the SCC was manufactured in the simulated corrosive environmental conditions on Inconel 600 tube that widely applied in the nuclear power plants. The tensile stress which is one of the main factors to induce SCC was given by GTAW welding in the inner surface of the specimen. The corrosive environment was simulated by using the sodium hydroxide (NaOH) and sodium sulfide (Na 2 S). In this study, SCC was manufactured in the simulated corrosive environmental conditions with Inconel 600 tube that widely applied in the nuclear power plants. 1) The SCC was manufactured on Inconel 600 tube in simulated operational environments of nuclear power plants. In the experiment, the welding heat input which is enough to induce the cracking generated the SCC near the welding bead. So, in order to prevent the SCC, the residual stress on structure should be relaxed. 2) The branch-type cracking was detected

SCC in acidic, neutral, and alkaline environments

International Nuclear Information System (INIS)

Anon.

1996-01-01

This group considered the following: (1) What features characterized SCC in the different environments? (2) What are the phenomenological correlations that presently describe SCC and how good are these? (3) What modeling is now available for all or some part of the subject? (4) What are the elements and sub-elements for an ideal model which would adequately describe the subject? and (5) What work has yet to be done to organize an adequate model?

Characteristics of SCC with Fly Ash and Manufactured Sand

Science.gov (United States)

Praveen Kumar, K.; Radhakrishna

2016-09-01

Self compacting concrete (SCC) of M40 grade was designed. The binder in SCC consists of OPC and fly ash in the ratio of 65:35. River sand was replaced by manufactured sand (M-sand) at replacement levels of 20,40,60,80 and 100%. An attempt was made to evaluate the workability and strength characteristics of self compacting concrete with river sand and manufactured sand as fine aggregates. For each replacement level, constant workability was maintained by varying the dosage of superplasticizer. T50 flow time, V Funnel time, V-funnel T5 time as well as compressive, split tensile and flexural strength of SCC were found at each replacement level of M-sand. They were compared to SCC with river sand. Results indicate favourable use of M-sand in preparation of Self Compacting Concrete.

Self-compacting concretes (SCC: comparison of methods of dosage

Directory of Open Access Journals (Sweden)

B. F. Tutikian

Full Text Available The composition of a self-compacting concrete (SCC should be defined to fulfills a number of requirements, such as self-compactibility, strength and durability. This study aims to compare three methods of dosage for SCC with local materials, so as to determine which one is the most economical and rational, thus assisting the executor in making a decision and enabling economic and technical feasibility for its application. The methods used in the experimental program were: Nan Su et al., which was developed in 2001 [1]; Repette-Melo, which was proposed in 2005 [2]; and Tutikian & Dal Molin, which was developed in 2007 [3]. From the results obtained in the experimental program, it was observed that the method which presented the lowest cost and highest compressive strength at the ages of 7, 28 and 91 days was Tutikian & Dal Molin, while the one which reached the lowest chloride ion penetration, best compactness and highest elasticity modulus was Repette-Melo. In tests carried out in the fresh state, all tested methods yielded mixtures which comply with the self-compactibility levels required by ABNT NBR 15823:2010 [4].

Potential of utilizing asphalt dust waste as filler material in the production of sustainable self compacting concrete (SCC)

Science.gov (United States)

Ismail, Isham; Shahidan, Shahiron; Bahari, Nur Amira Afiza Saiful

2017-12-01

Waste materials from many industries are widely used in the production of sustainable green concrete. Utilizing asphalt dust waste (ADW) as a filler material in the development of self-compacting concrete (SCC) is one of the alternative solutions for reducing environmental waste. SCC is an innovative concrete that does not require vibration for placing and compaction. However, there is limited information on the effects of utilizing ADW in the development of SCC. Therefore, this research study examines the effects of various w/b ratios (0.2, 0.3 and 0.4) and differing amounts of ADW (0% to 50%) on the rheological properties of fresh state concrete. The compressive strength of the SCC was tested only for 7 and 28 days as preliminary studies. The results revealed that mixtures MD730, MD740 and MD750 showed satisfactory results for the slump flow, J-Ring, L-Box and V-Funnel test during the fresh state. The compressive strength values obtained after 28 days for MD730, MD740 and MD750 were 35.1 MPa, 36.8 MPa and 29.4 MPa respectively. In conclusion, the distribution of materials in mixtures has significant effect in achieving rheological properties and compressive strength of SCC.

Program of in-pile IASCC testing under the simulated actual plant condition. Development of technique for in-pile IASCC initiation test in JMTR

International Nuclear Information System (INIS)

Ugachi, Hirokazu; Tsukada, Takashi; Kaji, Yoshiyuki; Nagata, Nobuaki; Dozaki, Koji; Takiguchi, Hideki

2003-01-01

Irradiation assisted stress corrosion cracking (IASCC) is caused by the synergistic effects of neutron irradiation, stress and corrosion by high temperature water. It is, therefore, essential to perform in-pile SCC tests, which are material tests under the conditions simulating those of actual LWR operation, in order to clarify the precise mechanism of the phenomenon, though mainly out-of-pile SCC tests for irradiated materials have been carried out in this research field. There are, however, many difficulties to perform in-pile SCC tests. Performing in-pile SCC tests, essential key techniques must be developed. Hence as a part of development of the key techniques for in-pile SCC tests, we have embarked on development of the test technique which enables us to obtain the information concerning the effect of such parameters as applied stress level, water chemistry, irradiation conditions, etc. on the crack initiation behavior. Although it is difficult to detect the crack initiation in in-pile SCC tests, the crack initiation can be evaluated by the detection of specimen rupture if the cross section area of the specimen is small enough. Therefore, we adopted the uniaxial constant loading (UCL) test with small tensile specimens. This paper will describe the current status of the development of several techniques for in-pile SCC initiation tests in JMTR and the results of the performance tests of the designed testing unit using the out-of-pile loop facility. (author)

SCC: Semantic Context Cascade for Efficient Action Detection

KAUST Repository

Heilbron, Fabian Caba

2017-11-09

Despite the recent advances in large-scale video analysis, action detection remains as one of the most challenging unsolved problems in computer vision. This snag is in part due to the large volume of data that needs to be analyzed to detect actions in videos. Existing approaches have mitigated the computational cost, but still, these methods lack rich high-level semantics that helps them to localize the actions quickly. In this paper, we introduce a Semantic Cascade Context (SCC) model that aims to detect action in long video sequences. By embracing semantic priors associated with human activities, SCC produces high-quality class-specific action proposals and prune unrelated activities in a cascade fashion. Experimental results in ActivityNet unveils that SCC achieves state-of-the-art performance for action detection while operating at real time.

Evaluation of the Frequencies for Canister Inspections for SCC

Energy Technology Data Exchange (ETDEWEB)

Stockman, Christine [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bryan, Charles R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2016-02-02

This report fulfills the M3 milestone M3FT-15SN0802042, “Evaluate the Frequencies for Canister Inspections for SCC” under Work Package FT-15SN080204, “ST Field Demonstration Support – SNL”. It reviews the current state of knowledge on the potential for stress corrosion cracking (SCC) of dry storage canisters and evaluates the implications of this state of knowledge on the establishment of an SCC inspection frequency. Models for the prediction of SCC by the Japanese Central Research Institute of Electric Power Industry (CRIEPI), the United States (U.S.) Electric Power Research Institute (EPRI), and Sandia National Laboratories (SNL) are summarized, and their limitations discussed.

Intergranular cracking mechanism in baffle former bolt materials for PWR core internals

Energy Technology Data Exchange (ETDEWEB)

Yonezawa, Toshio; Arioka, Koji; Kanasaki, Hiroshi; Fujimoto, Koji [Takasago R and D Center, Mitsubishi Heavy Industries Ltd., Takasago, Hyogo (Japan); Ajiki, Kazuhide [Kobe Shipyard and Machinery, Mitsubishi Heavy Industries Ltd., Kobe, Hyogo (Japan); Matsuoka, Takanori [Nuclear Development Corp., Tokai, Ibaraki (Japan); Urata, Sigeru; Mizuta, Hitoshi [Kansai Electric Power Co., Inc., Osaka (Japan)

2000-03-01

In this study, the cause of intergranular cracking in baffle former bolts(BFBs) was estimated from metallurgical and chemical viewpoints based upon the experimental data and information published by EdF. At first, five kinds of possibilities were estimated as the cause of intergranular cracking in BFBs. Five possibilities estimated were (1) mechanical cracking caused by high strain in irradiation hardened austenitic stainless steels, (2) O{sub 2} SCC due to residual oxygen in the bolt stagnant region, (3) caustic SCC due to dry and wet phenomenon, (4) low pH SCC due to oxygen concentration cell, and (5) PWSCC due to radiation induced segregation. In this study each possibility was evaluated by the calculation and some out of pile tests. And also, the cause of the intergranular cracking in BFBs was estimated by the data of the post-irradiation examinations and basic out of pile tests for Type 316CW and Type 347 stainless steels in the authors' previous study. From these evaluation, the intergranular cracking in BFBs seems to be caused by the PWSCC, but not caused by mechanical cracking O{sub 2} SCC, caustic SCC or low pH SCC. (author)

The behavior of self-compacting concrete (SCC) with bagasse ash

Science.gov (United States)

Hanafiah, Saloma, Whardani, Putri Nurul Kusuma

2017-11-01

Self-Compacting Concrete (SCC) has the ability to flow and self-compacting. One of the benefit of SCC can reduced the construction time and labor cost. The materials to be used for see slightly different with the conventional concrete. Less coarse aggregate to be used up to 50%. The maximum size of coarse aggregate was also limited e.g. 10 mm. Other material was quartz sand with grain size of 50-650 µm. For reducing the around of cement, bagasse ash was used as partial replacement of cement. In this research, the variations of w/c to be used, e.g. 0.275, 0.300, 0.325 and the percentage of bagasse ash substitution were 10%, 15%, and 20%. EFNARC standard was conducted for slump flow test following the V-funnel test and L-box shape test. The maximum value of slump flow test was 75.75 cm, V-funnel test was 4.95 second, and L-box test was 1.000 yielded by mixture with w/c = 0.325 and 0% of bagasse ash. The minimum value of slump flow test was 61.50 cm, V-funnel test is 21.05 second, and L-box test was 0.743 yielded by mixture with w/c = 0.275 and 20% of bagasse ash. The maximum value of compressive strength was 67.239 MPa yielded by mixture with w/c = 0.275 and 15% of bagasse ash. And the minimum value of compressive strength was 41.813 MPa yielded by mixture with w/c = 0.325 and 20% bagasse ash.

Metazoan Scc4 homologs link sister chromatid cohesion to cell and axon migration guidance

NARCIS (Netherlands)

V.C. Seitan (Vlad); P.A. Banks (Peter); S. Laval (Steve); N.A. Majid (Nazia); D. Dorsett (Dale); A. Rana (Amer); J. Smith (Jeremy); A. Bateman (Alex); S. Krpic (Sanja); A. Hostert (Arnd); S.M. Rollins; H. Erdjument-Bromage (Hediye); P. Tempst (Paul); C.Y. Benard (Claire); S. Hekimi (Siegfried); S.F. Newbury (Sarah); T. Strachan (Tom)

2006-01-01

textabstractSaccharomyces cerevisiae Scc2 binds Scc4 to form an essential complex that loads cohesin onto chromosomes. The prevalence of Scc2 orthologs in eukaryotes emphasizes a conserved role in regulating sister chromatid cohesion, but homologs of Scc4 have not hitherto been identified outside

Analysis of SCC initiation/propagation behavior of stainless steels in LWR environments

International Nuclear Information System (INIS)

Saito, Koichi; Kuniya, Jiro

1999-01-01

This paper presents a method to analyze initiation and propagation behavior of stress corrosion cracking (SCC) of stainless steels on the basis of a new prediction algorithm in which the initiation period and propagation period of SCC under irradiation conditions are considered from a practical viewpoint. The prediction algorithm is based on three ideas: (1) threshold neutron fluence of radiation-enhanced SCC (RESCC), (2) equivalent critical crack depth, and (3) threshold stress intensity factor for SCC (K ISCC ). SCC initiation/propagation behavior in light water reactor (LWR) environments is analyzed by incorporating model equations on irradiation hardening, irradiation-enhanced electrochemical potentiokinetic reactivation (EPR) and irradiation stress relaxation that are phenomena peculiar to neutron irradiation. The analytical method is applied to predict crack growth behavior of a semi-elliptical surface crack in a flat plane that has an arbitrary residual stress profile; specimens are sensitized type 304 stainless steels which had been subjected to neutron irradiation in high temperature water. SCC growth behavior of a semi-elliptical surface crack was greatly dependent on the distribution of residual stress in a flat plane. When residual stress at the surface of the flat plane was relatively small, the method predicted SCC propagation did not take place. (author)

SCC crack growth rate of cold worked 316L stainless steel in PWR environment

Science.gov (United States)

Du, Donghai; Chen, Kai; Yu, Lun; lu, Hui; Zhang, Lefu; Shi, Xiuqiang; Xu, Xuelian

2015-01-01

Many component failures in nuclear power plants were found to be caused by stress corrosion cracking (SCC) of cold worked austenitic steels. Some of the pressure boundary component materials are even cold worked up to 35% plastic deformation, leaving high residual stress and inducing high growth rate of corrosion crack. Controlling water chemistry is one of the best counter measure to mitigate this problem. In this work, the effects of temperature (200 up to 325 °C) and dissolved oxygen (0 up to 2000 μg/L) on SCC crack growth rates of cold worked austenitic stainless steel type 316L have been tested by using direct current potential drop (DCPD) method. The results showed that temperature affected SCC crack growth rates more significantly in oxygenated water than in deaerated water. In argon deaerated water, the crack growth rate exhibited a peak at about 250 °C, which needs further verification. At 325 °C, the SCC crack growth rate increased rapidly with the increase of dissolved oxygen concentration within the range from 0 up to 200 μg/L, while when dissolved oxygen was above 200 μg/L, the crack growth rate followed a shallower dependence on dissolved oxygen concentration.

Mechanical properties of Self-Consolidating Concrete incorporating Cement Kiln Dust

Directory of Open Access Journals (Sweden)

Mostafa Abd El-Mohsen

2015-04-01

Full Text Available Self-Consolidating Concrete (SCC has been widely used in both practical and laboratory applications. Selection of its components and their ratios depends, mainly, on the target mechanical and physical properties recommended by the project consultant. Partial replacement of cement in SCC with cheap available industrial by-product could produce environmentally durable concrete with similar properties of normal concrete. In the current research, SCC was produced by blending Cement Kiln Dust (CKD with cement in different ratios. Four mixes incorporating cement kiln dust with partial cement replacement of 10%, 20%, 30%, and 40% were produced and compared with a control mix of Normally Vibrated Concrete (NVC. Superplasticizer was used to increase the flow-ability of SCC mixes. The fresh and hardened mechanical properties of all mixes were determined and evaluated. Moreover, time-dependent behavior was investigated for all mixes in terms of drying shrinkage test. The shrinkage strain was measured for all specimens for a period of 120 days. Based on the experimental results, it was found that SCC mixture containing 20% cement replacement of CKD exhibited the highest mechanical strength compared to other SCC mixes and NVC mix as well. It was observed that the volumetric changes of specimens were directly proportional to the increase of the cement replacement ratio.

Maintenance technologies for SCC of PWR

International Nuclear Information System (INIS)

Okimura, Koji; Hori, Nobuyuki; Kanzaki, Hiroshi; Tokuhisa, Kiichi; Kamo, Kazuhiko; Kurokawa, Masaaki

2007-01-01

The recent technologies of test, relaxation of deterioration, repairing and change of materials are explained for safe and stable operation of pressurized water reactor (PWR). Stress corrosion cracking (SCC) is originated by three factors such as materials, stress and environment. The eddy current test (ECT) method for the stream generator pipe and the ultrasonic test method for welding part of pipe were developed as the test technologies. Primary water stress corrosion cracking (PWSCC) of Inconel 600 in the welding part is explained. The shot peening of instrument in the gas, the water jet peening of it in water, and laser irradiation on the surface are illustrated as some examples of improvement technology of stress. The cladding of Inconel 690 on Inconel 600 is carried out under the condition of environmental cut. Total or some parts of the upper part of reactor, stream generator and structure in the reactor are changed by the improvement technologies. Changing Inconel 600 joint in the exit pipe of reactor with Inconel 690 is illustrated. (S.Y.)

SCC of 2304 Duplex Stainless Steel-Microstructure, Residual Stress and Surface Grinding Effects.

Science.gov (United States)

Zhou, Nian; Peng, Ru Lin; Schönning, Mikael; Pettersson, Rachel

2017-02-23

The influence of surface grinding and microstructure on chloride induced stress corrosion cracking (SCC) behavior of 2304 duplex stainless steel has been investigated. Grinding operations were performed both parallel and perpendicular to the rolling direction of the material. SCC tests were conducted in boiling magnesium chloride according to ASTM G36; specimens were exposed both without external loading and with varied levels of four-point bend loading. Residual stresses were measured on selected specimens before and after exposure using the X-ray diffraction technique. In addition, in-situ surface stress measurements subjected to four-point bend loading were performed to evaluate the deviation between the actual applied loading and the calculated values according to ASTM G39. Micro-cracks, initiated by grinding induced surface tensile residual stresses, were observed for all the ground specimens but not on the as-delivered surfaces. Loading transverse to the rolling direction of the material increased the susceptibility to chloride induced SCC. Grinding induced tensile residual stresses and micro-notches in the as-ground surface topography were also detrimental.

SCC of 2304 Duplex Stainless Steel—Microstructure, Residual Stress and Surface Grinding Effects

Directory of Open Access Journals (Sweden)

Nian Zhou

2017-02-01

Full Text Available The influence of surface grinding and microstructure on chloride induced stress corrosion cracking (SCC behavior of 2304 duplex stainless steel has been investigated. Grinding operations were performed both parallel and perpendicular to the rolling direction of the material. SCC tests were conducted in boiling magnesium chloride according to ASTM G36; specimens were exposed both without external loading and with varied levels of four-point bend loading. Residual stresses were measured on selected specimens before and after exposure using the X-ray diffraction technique. In addition, in-situ surface stress measurements subjected to four-point bend loading were performed to evaluate the deviation between the actual applied loading and the calculated values according to ASTM G39. Micro-cracks, initiated by grinding induced surface tensile residual stresses, were observed for all the ground specimens but not on the as-delivered surfaces. Loading transverse to the rolling direction of the material increased the susceptibility to chloride induced SCC. Grinding induced tensile residual stresses and micro-notches in the as-ground surface topography were also detrimental.

SCC of 2304 Duplex Stainless Steel—Microstructure, Residual Stress and Surface Grinding Effects

Science.gov (United States)

Zhou, Nian; Peng, Ru Lin; Schönning, Mikael; Pettersson, Rachel

2017-01-01

The influence of surface grinding and microstructure on chloride induced stress corrosion cracking (SCC) behavior of 2304 duplex stainless steel has been investigated. Grinding operations were performed both parallel and perpendicular to the rolling direction of the material. SCC tests were conducted in boiling magnesium chloride according to ASTM G36; specimens were exposed both without external loading and with varied levels of four-point bend loading. Residual stresses were measured on selected specimens before and after exposure using the X-ray diffraction technique. In addition, in-situ surface stress measurements subjected to four-point bend loading were performed to evaluate the deviation between the actual applied loading and the calculated values according to ASTM G39. Micro-cracks, initiated by grinding induced surface tensile residual stresses, were observed for all the ground specimens but not on the as-delivered surfaces. Loading transverse to the rolling direction of the material increased the susceptibility to chloride induced SCC. Grinding induced tensile residual stresses and micro-notches in the as-ground surface topography were also detrimental. PMID:28772582

Mechanical properties of self-compacting concrete state-of-the-art report of the RILEM technical committee 228-MPS on mechanical properties of self-compacting concrete

CERN Document Server

Schutter, Geert

2014-01-01

The State-of-the-Art Report of RILEM Technical Committee 228-MPS on Mechanical properties of Self-Compacting Concrete (SCC) summarizes an extensive body of information related to mechanical properties and mechanical behaviour of SCC. Due attention is given to the fact that the composition of SCC varies significantly. A wide range of  mechanical properties are considered, including compressive strength, stress-strain relationship, tensile and flexural strengths, modulus of elasticity, shear strength, effect of elevated temperature, such as fire spalling and residual properties after fire, in-situ properties, creep, shrinkage, bond properties, and structural behaviour. A chapter on fibre-reinforced SCC is included, as well as a chapter on specialty SCC, such as light-weight SCC, heavy-weight SCC, preplaced aggregate SCC, special fibre reinforced SCC, and underwater concrete.

The Effect of the Kind of Sands and Additions on the Mechanical Behaviour of S.C.C

Science.gov (United States)

Zeghichi, L.; Benghazi, Z.; Baali, L.

The sand is an inert element essential in the composition of concrete; its use ensures granular continuity between the cement and gravel for better cohesion of concrete. This paper presents the results of a study that investigated the influence of sand quality on the properties of fresh and hardened self-compacting concrete (SCC). The dune sands are very fine materials characterized by a high intergranular porosity, high surface area and low fineness modulus; on the other hand crushed (manufactured) sand has a high rate into thin and irregular shapes which are influencing the workability of concrete. The amount of dune sand varies from (0% 50%, to 100%) by weight of fine aggregates. The effect of additions is also treated (blast furnace slag and lime stone) The results show that the rheological properties favour the use of dune sands; however the mechanical properties support the use of crushed sand.

Crystal Structure of the Cohesin Gatekeeper Pds5 and in Complex with Kleisin Scc1

Directory of Open Access Journals (Sweden)

Byung-Gil Lee

2016-03-01

Full Text Available Sister chromatid cohesion is mediated by cohesin, whose Smc1, Smc3, and kleisin (Scc1 subunits form a ring structure that entraps sister DNAs. The ring is opened either by separase, which cleaves Scc1 during anaphase, or by a releasing activity involving Wapl, Scc3, and Pds5, which bind to Scc1 and open its interface with Smc3. We present crystal structures of Pds5 from the yeast L. thermotolerans in the presence and absence of the conserved Scc1 region that interacts with Pds5. Scc1 binds along the spine of the Pds5 HEAT repeat fold and is wedged between the spine and C-terminal hook of Pds5. We have isolated mutants that confirm the observed binding mode of Scc1 and verified their effect on cohesin by immunoprecipitation and calibrated ChIP-seq. The Pds5 structure also reveals architectural similarities to Scc3, the other large HEAT repeat protein of cohesin and, most likely, Scc2.

Effects of microstructure and mechanical properties of alloys 600 an 690 on secondary side SCC

International Nuclear Information System (INIS)

Vaillant, F.; Buisine, D.; Prieux, B.; Fournel, J.C.; Gelpi, A.

1996-03-01

Modeling for secondary side cracking is needed to understand the behaviour of alloy 600 in plants. They require a comprehensive understanding of the various influences of the material properties on Stress Corrosion Cracking (SCC), based on field experience and laboratory data. In an attempt to predict the materials effects on SCC behaviour of new steam generators, laboratory corrosion data of alloy 690 were overviewed. French field experience with steam generators equipped with drilled tube support plates (TSPs) has demonstrated that the lower the yield stress (YS) and the carbon content, the higher the susceptibility t secondary side cracking of mill-annealed (MA) alloy 600. Also heat treated (700 deg. C x 16 h) tubing has been shown to have a much better resistance, but this excellent resistance could not be attributed only to the material properties. In laboratory environments, particularly in caustics, results have confirmed several of the above mentioned key findings on alloy 600: in caustic environments and under constant loading, tubes fabricated from MA alloy 600 with low YS have exhibited the worst resistance to initiation; YS was found to be the most accurate parameter to account for the behaviour of MA alloy 600. A heat treatment at 700 deg. C appeared to reduce the propagation rates of cracks in alloy 600. The best IGSCC resistance of alloy 690 was obtained for tubes with intergranular precipitation of carbides. TT (700 deg. C) significantly improved the propagation resistance of alloy 690; in acidic and neutral sulfate environments, IGSCC of alloy 600 was not strongly dependent on the microstructure in the MA condition, but sensitization was detrimental. When alloy 600 and particularly alloy 690 were thermally treated at 700 deg. C x 16 h, the resistance to IGSCC was significantly improved. Tests performed on alloy 690 have shown a better resistance to IGSCC initiation and propagation than alloy 600, in NaOH and acidic sulfate environments. (authors

The effect of w/c ratio on microstructure of self-compacting concrete (SCC) with sugarcane bagasse ash (SCBA)

Science.gov (United States)

Hanafiah, Saloma, Victor, Amalina, Khoirunnisa Nur

2017-11-01

Self-Compacting Concrete (SCC) is a concrete that can flow and compact by itself without vibrator. The ability of SCC to flow by itself makes this concrete very suitable for construction that has very small reinforcement gaps. In this study, SCC was designed to get a compressive strength above 60 MPa at the age of 28 days. Sugarcane bagasse ash was used as substitution material for cement replacement. Percentages of sugarcane bagasse ash used were 10%, 15%, and 20%. There were three w/c values that vary from 0.275, 0.300, and 0.325. Testing standards referred to ASTM, EFNARC and ACI. The fresh concrete test was slump flow, L-box and V-funnel. The maximum compressive strength was in the mixture with the sugarcane bagasse ash composition of 15% and w/c=0.275 which was 67.24 MPa. The result of SEM test analysis found that the mixture composition with 15% sugarcane bagasse ash has solid CSH structure, small amount of pores, and smaller pore diameter than other mixtures.

SCC of Alloy 600 in PWR steam generator tubes

International Nuclear Information System (INIS)

Pascali, R.; Buzzanca, G.; Quaglia, G.M.; Ronchetti, C.

1986-01-01

The studies reported in this paper concern the evaluation of Alloy 600 and 690 behaviour in chemical agressive conditions simulating the concentration film on heat exchanging tube. The corrosion tests have been performed to evidence the influence of metallurgical conditions and different heats. Various devices for reproducing dead areas and steam blanketing have been designed and tested, such as, umbrellas, rings, thin deposits, etc. A system to reproduce the S.G. areas with thick deposits has been designed successively and set up in a previous series of tests, in boiling water at 56 kg/cm/sup 2/, 270 0 C and heat flux 45 W/cm/sup 2/. Caustic SCC tests have been carried out in adiabatic conditions also using small autoclaves

Mechanical Behavior of Self-Compacting Concrete Containing Nano-Metakaolin

Directory of Open Access Journals (Sweden)

Mohammed Kareem Abed

2017-08-01

Full Text Available This paper presents the influence of nano- metakaolin addition for production self-compacting concrete (SCC. Nano-metakaolin material was used at four percentages (0, 1, 3 and 5 % as partial replacement by weight of cement [Reference mix (PC, (1%, 3%, 5% nano-metakaolin(1, 3, 5 NMK]. This research studied the influence of nano-metakaolin material on the fresh and mechanical properties which represented by the different tests were slump flow, T50cm, L-Box, V-funnel, compressive and flexural strength. From the results of this study, found that the SCC with 5% of nano-metakaolin material as partial replacement by weight of cement give the best results of fresh and mechanical properties of SCC mixes.

Evaluating the SCC resistance of underwater welds in sodium tetrathionate

International Nuclear Information System (INIS)

White, R.A.; Angeliu, T.M.

1997-01-01

The susceptibility of welds to stress corrosion cracking (SCC) is enhanced by the surface residual tensile stresses generated by the typical welding process. However, underwater plasma transferred arc (PTA) welding has been shown to produce compressive surface residual stresses, an encouraging result if repairs of cracked boiling water reactor (BWR) components are to be made without further endangering them to SCC. This program was designed to verify that underwater PTA welds are resistant to SCC and to determine if underwater PTA welding could mitigate SCC in potentially susceptible welds. This was achieved by exposing various welds on solution annealed (SA) and SA + thermally sensitized 304 stainless steel at 25 C in a solution of 1.5 gm/liter of sodium sulfide added to 0.05M sodium tetrathionate, titrated to a pH of 1.25 with H 2 SO 4 . The autogeneous welds were produced using gas tungsten arc (GTA) and plasma transferred arc (PTA) welding under atmospheric conditions, and PTA welding underwater. After 1 hour of sodium tetrathionate exposure, GTA and air PTA welds exhibited SCC while the underwater PTA weld heat affected zones were more resistant. Underwater PTA welds bisecting a GTA weld eliminated the cracking in the GTA weld heat affected zone under certain conditions. The lack of IG cracking in the region influenced by the underwater PTA weld is consistent with the measurement of compressive surface residual stresses inherent to the underwater welding process

The clinical significance of serum SCC-Ag combined with CD105 in patients with cervical cancer during the early stage diagnosis

Directory of Open Access Journals (Sweden)

Ru-Chan Ma

2016-09-01

Full Text Available Objective: To invest the clinical significance of serum SCC-Ag combined with CD105 in early diagnosis of cervical cancer to provide new ideas for early diagnosis and clinical treatment of cervical cancer. Methods: A total of 74 cases cervical cancer patients were selected as cervical cancer group, and 52 cases uterine fibroids patients were selected as normal cervical group, serum samples were collected in the early morning fasting condition, SCC-Ag and CD105 were checked by ELISA method, SCC-Ag and CD105 of two groups were analyzed by t-test, and to compare SCC-Ag and CD105 in different TMN staging, lymph gland metastasis and non-lymph gland metastasis in patients with cervical cancer, the correlation analysis was used by Pearson correlation analysis method. Results: These results came from ELISA method, comparing with normal cervical group, the SCC-Ag and CD105 of cervical cancer group increased, the difference was statistically significant. Comparing with Ⅰ period of TMN staging, SCC-Ag and CD105 of Ⅱ period increased, Ⅲ, Ⅳ period increased, the difference was statistically significant. Comparing with Ⅱ period, SCC-Ag and CD105 of Ⅲ, Ⅳ period increased, the difference was statistically significant. Comparing with non-lymph gland metastasis, SCC-Ag and CD105 of lymph gland metastasis increased in cervical cancer with surgical treatment, the difference was statistically significant. According to Pearson correlation analysis, SCC-Ag and CD105 were positively correlated. Conclusion: SCC-Ag and CD105 in patients with cervical cancer increase highly, it has important clinical value that of serum SCCAg combined with CD105 in the early diagnosis of cervical cancer, especially it has clinical guiding significance to staging and lymph gland metastasis of cervical cancer, and it is worthy of clinical reference.

Assessment and management of SCC in a liquid pipeline: case study

Energy Technology Data Exchange (ETDEWEB)

Cazenave, Pablo; Tandon, Samarth; Gao, Ming; Krishnamurthy, Ravi [Blade Energy Partners, Houston, Texas (United States); Peverelli, Romina (PIMS of London, London (United Kingdom)); Moreno Ochoa, Carlos (Pemex Refinacion, Cd de Mexico, (Mexico)); Diaz Solis, Esau (Pemex Refinacion, Cd de Mexico, (Mexico))

2010-07-01

A 30-inch crude oil pipeline system was built between Nuevo Teapa to Venta de Carpjo from 1978 to 1980. It is owned by Pemex; its total length is 570 km, and it has strategic importance in Mexico's refining capability. In this oil pipeline, various degrees of external and internal corrosion have been found, and recent incidents occurred as a result of stress corrosion cracking (SCC). This paper presents an approach for managing high pH SCC in such a pipeline: it includes a comprehensive verification excavation plan, a strict in-ditch NDT investigation protocol, statistical models to determine the probability of detection and identification, sizing tolerance analyses, and an assessment methodology that is backed up by the material testing program. All the results provided by the application of the approach lead to the development of integrity management strategies. An integrity management plan is established and refined before the next inspection.

Effect of Strength and Microstructure on Stress Corrosion Cracking Behavior and Mechanism of X80 Pipeline Steel in High pH Carbonate/Bicarbonate Solution

Science.gov (United States)

Zhu, Min; Du, Cuiwei; Li, Xiaogang; Liu, Zhiyong; Wang, Shengrong; Zhao, Tianliang; Jia, Jinghuan

2014-04-01

The stress corrosion cracking (SCC) behaviors and mechanisms of X80 pipeline steels with different strength and microstructure in high pH carbonate/bicarbonate solution were investigated by slow strain rate testing and electrochemical test. The results showed that the cracking mode of low strength X80 steel composed of bulky polygonal ferrite and granular bainite in high pH solution was intergranular (IGSCC), and the SCC mechanism was anodic dissolution (AD). While the mixed cracking mode of high strength X80 steel consisted of fine acicular ferrite and granular bainite was intergranular (IGSCC) in the early stage, and transgranular (TGSCC) in the later stage. The decrease of pH value of crack tip was probably the key reason for the occurrence of TGSCC. The SCC mechanism may be a mixed mode of AD and hydrogen embrittlement (HE), and the HE mechanism may play a significant role in the deep crack propagation at the later stage. The cracking modes and SCC mechanisms of the two X80 steels were associated with its microstructure and strength.

Effects of fluoride and aluminum on expressions of StAR and P450scc of related steroidogenesis in guinea pigs' testis.

Science.gov (United States)

Dong, Chunguang; Cao, Jinling; Cao, Chunfang; Han, Yichao; Wu, Shouyan; Wang, Shaolin; Wang, Jundong

2016-03-01

A lot of studies have shown that fluoride and aluminum have toxic effect on male reproductive system, but the mechanism of which and the interaction between fluoride and aluminum is still unknown. This study investigated the effects of fluoride (NaF) or/and aluminum (AlCl3) on serum testosterone level, gene and protein expression levels of Steroidogenic Acute Regulatory Protein (StAR) and Cytochrome P450 cholesterol side chain cleavage enzyme (P450scc) in the testes of guinea pigs. Fifty-two guinea pigs were divided randomly into four groups (Control, HiF, HiAl and HiF + HiAl). Fluoride (150 mg NaF/L) or/and aluminum (300 mg AlCl3/L) were orally administrated to male guinea pigs for 13 weeks. The results showed that F and Al reduced number and elevated abnormal ratio of sperm. Meanwhile, the concentrations of serum testosterone in all experimental groups were decreased. P450scc protein expression was significantly reduced in all treatment groups, and StAR expression was decreased remarkably in HiF group and HiF + HiAl group. The levels of StAR mRNA in three groups were reduced by 53.9%, 21.4% and 33.4%, respectively, while the expressions of P450scc mRNA were reduced by 67.8%, 17.0% and 47.8%. Therefore, we concluded that F induced the reduction in testosterone and sperm amount, and thus in lower fertility, which might occur as a consequence of depressed StAR and P450scc mRNA expression. There were no synergistic effects between F and Al, instead, Al weakened the toxicity of F to some extents. The results indicated that Al had antagonism effects on F. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development of BWR components SCC mitigation method by the TiO{sub 2} treating technique

Energy Technology Data Exchange (ETDEWEB)

Takamori, K.; Suzuki, J.; Suzuki, S.; Miyazaki, A. [Tokyo Electric Power Co., Tokohama-city (Japan); Okamura, M.; Osato, T.; Ichikawa, N. [Toshiba Corp., Kawasaki-city (Japan); Urata, H.; Takagi, J. [Toshiba Corp., Yokohama-city (Japan)

2007-07-01

Stress Corrosion Cracking (SCC) susceptibility of Boiling Water Reactor (BWR) materials is mitigated by reduction of the electrochemical corrosion potential (ECP). In the reactor there is a photo-excitation reaction between TiO{sub 2} and ultraviolet Cherenkov radiation. The TiO{sub 2} treatment technique plans to mitigate SCC by reducing the ECP without hydrogen addition. We conducted the demonstration tests of the TiO{sub 2} treatment technique in a test reactor and in BWR plant piping systems. The test results showed that the ECP of TiO{sub 2} treated type 316L stainless steel and the Ni based alloy 600 were reduced to -350 mV vs. the standard hydrogen electrode (SHE) in the reactor system in normal water chemistry (NWC). In the no Cherenkov radiation area, the ECP of the TiO{sub 2} treated stainless steel still decreased as the dissolved hydrogen concentration in feed water up to 0.3 ppm. (a condition that will be referred as 'low HWC.') (author)

Structure of the Pds5-Scc1 Complex and Implications for Cohesin Function

Directory of Open Access Journals (Sweden)

Kyle W. Muir

2016-03-01

Full Text Available Sister chromatid cohesion is a fundamental prerequisite to faithful genome segregation. Cohesion is precisely regulated by accessory factors that modulate the stability with which the cohesin complex embraces chromosomes. One of these factors, Pds5, engages cohesin through Scc1 and is both a facilitator of cohesion, and, conversely also mediates the release of cohesin from chromatin. We present here the crystal structure of a complex between budding yeast Pds5 and Scc1, thus elucidating the molecular basis of Pds5 function. Pds5 forms an elongated HEAT repeat that binds to Scc1 via a conserved surface patch. We demonstrate that the integrity of the Pds5-Scc1 interface is indispensable for the recruitment of Pds5 to cohesin, and that its abrogation results in loss of sister chromatid cohesion and cell viability.

Effect of overload on SCC growth in stainless steels in high temperature water

International Nuclear Information System (INIS)

Xue, He; Peng, Qunjia; Shoji, Tetsuo

2009-01-01

By incorporating the film slip-dissolution/oxidation model and the elastic-plastic finite element method (EPFEM), the effect of the overload on stress corrosion cracking (SCC) growth rate of stainless steel in high temperature water is discussed in this paper. Results show that SCC growth rate of a 20% cold worked 316L stainless steel in high temperature water decrease in the overload affected zone ahead of the growing crack tip. Therefore, a reasonable overload could availably reduce the SCC growth rate during a certain in-service period. (author)

Asphalt dust waste material as a paste volume in developing sustainable self compacting concrete (SCC)

Science.gov (United States)

Ismail, Isham; Shahidan, Shahiron; Bahari, Nur Amira Afiza Saiful

2017-12-01

Self-compacting concrete (SCC) mixtures are usually designed to have high workability during the fresh state through the influence of higher volumes of paste in concrete mixtures. Asphalt dust waste (ADW) is one of disposed materials obtained during the production of asphalt premix. These fine powder wastes contribute to environmental problems today. However, these waste materials can be utilized in the development of sustainable and economical SCC. This paper focuses on the preliminary evaluations of the fresh properties and compressive strength of developed SCC for 7 and 28 days only. 144 cube samples from 24 mixtures with varying water binder ratios (0.2, 0.3 and 0.4) and ADW volume (0% to 100%) were prepared. MD940 and MD950 showed a satisfactory performance for the slump flow, J-Ring, L-Box and V-Funnel tests at fresh state. The compressive strength after 28 days for MD940 and MD950 was 36.9 MPa and 28.0 MPa respectively. In conclusion, the use of ADW as paste volume should be limited and a higher water binder ratio will significantly reduce the compressive strength.

Fundamental and clinical evaluation of ''SCC RIABEAD'' kit for immunoradiometric assay of squamous cell carcinoma related antigen

International Nuclear Information System (INIS)

Koizumi, Mitsuru; Endo, Keigo; Nakajima, Kotoko

1987-01-01

A commercial ''SCC RIABEAD'' kit for immunoradiometric assay of squamous cell carcinoma related antigen (SCC antigen) was fundamentally and clinically evaluated. Laboratory performance was satisfactory for intra-assay and inter-assay reproducibility, recovery, and dilution, with rapid and simple measurement techniques. Seropositivity for SCC antigen was significantly higher for squamous cell carcinoma of the liver and uterine cervix than the other histology types. In the case of cervical squamous cell carcinoma, it increased with progressing disease. Post-treatment serum levels of SCC antigen returned to negative. SCC antigen is considered to be a useful tumor marker for these diseases. There was a good correlation between the measurement values obtained from the present and conventional (SCC RIAKIT) assays. The present assay remarkably decreased false-positive cases of pulmonary benign diseases. The results showed a ''SCC RIABEAD'' to be a favorable kit for immunoradiometric assay of SSC antigen, as compared with conventional assay kit. (Namekawa, K.)

Prediction of the impact of flow induced inhomogeneities in Self Compacting Concrete (SCC)

DEFF Research Database (Denmark)

Spangenberg, Jon; Roussel, N.; Hattel, Jesper Henri

2010-01-01

SCC is nowadays a worldwide used construction material. However, heterogeneities induced by casting may lead to variations of local properties and hence to a potential decrease of the structure’s load carrying capacity. The heterogeneities in SCC are primarily caused by static and dynamic segrega...

Characteristics of Aerococcus viridans isolated from bovine subclinical mastitis and its effect on milk SCC, yield, and composition.

Science.gov (United States)

Sun, Meng; Gao, Jian; Ali, Tariq; Yu, Dan; Zhang, Shiyao; Khan, Saeed U; Fanning, Séamus; Han, Bo

2017-04-01

Aerococcus viridians (A. viridans), an environmental Gram-positive bacterium, has been documented to be associated with bovine mastitis. However, its exact role in bovine mastitis and the changes it brings about in milk characteristics are not yet known. The objectives of the current study were to describe the antibiotic resistance of A. viridans from bovine mastitis as well as the correlation between existence of this pathogen in udders and the somatic cell counts (SCC), daily milk yield, and composition of individual cow. One-year sampling for subclinical mastitis composite milk was conducted based on monthly DHI data from September 2013 to August 2014, in a commercial herd located in Beijing, China. All samples were cultured and pathogens were identified using microbiology method. A. viridians isolates were further identified by API identification system and 16S ribosomal RNA (rRNA) sequencing method. Kirby-Bauer disk diffusion method was used to test the antibiotic resistance of A. viridians against kinds of antimicrobial substance. SCC, milk yield, and milk composition data were from monthly Dairy Herd Improvement (DHI) results. Results showed that a total of 279 (16.67%) A. viridans isolates were identified from among 1674 bacterial isolates cultured from milk samples with high SCC. The incidence of mastitis caused by A. viridans was the highest (48-53%) during the summer season. Majority of the isolates were susceptible to most of antimicrobial compounds tested, especially to β-lactams, but were found to be resistant (50-90%) to aminoglycosides, sulfonamides, and tetracycline. The average SCC of the A. viridans infected cows was significantly higher (1000.0 × 10 3  cells/mL) (P  0.05) by 1.86 kg/day. Reductions were also observed in fat content (P > 0.05), lactose (P  0.05), whereas protein content increased significantly (P bovine subclinical mastitis wherein it exerts an effect on SCC, milk yield, and composition.

SCC susceptibility of cold-worked stainless steel with minor element additions

International Nuclear Information System (INIS)

Nakano, Junichi; Nemoto, Yoshiyuki; Tsukada, Takashi; Uchimoto, Tetsuya

2011-01-01

To examine the effects of minor elements on stress corrosion cracking (SCC) susceptibility of low carbon stainless steels with a work hardened layer, a high purity type 304 stainless steel was fabricated and minor elements, Si, S, P, C or Ti, were added. A work hardened layer was introduced by shaving on the surface of stainless steels. The specimens were exposed to a boiling 42% MgCl 2 solution for 20 h and the number and the length of initiated cracks were examined. SCC susceptibility of the specimen with P was the highest and that of the specimen with C was the lowest in all specimens. By magnetic force microscope examination, a magnetic phase expected to be a martensitic phase was detected near the surface. Since corrosion resistance of martensite is lower than that of austenite, the minor elements additions would affect SCC susceptibility through the amount of the transformed martensite.

Stress Corrosion Cracking of Steel and Aluminum in Sodium Hydroxide: Field Failure and Laboratory Test

Directory of Open Access Journals (Sweden)

Y. Prawoto

2012-01-01

Full Text Available Through an investigation of the field failure analysis and laboratory experiment, a study on (stress corrosion cracking SCC behavior of steel and aluminum was performed. All samples were extracted from known operating conditions from the field failures. Similar but accelerated laboratory test was subsequently conducted in such a way as to mimic the field failures. The crack depth and behavior of the SCC were then analyzed after the laboratory test and the mechanism of stress corrosion cracking was studied. The results show that for the same given stress relative to ultimate tensile strength, the susceptibility to SCC is greatly influenced by heat treatment. Furthermore, it was also concluded that when expressed relative to the (ultimate tensile strength UTS, aluminum has similar level of SCC susceptibility to that of steel, although with respect to the same absolute value of applied stress, aluminum is more susceptible to SCC in sodium hydroxide environment than steel.

NDE to Manage Atmospheric SCC in Canisters for Dry Storage of Spent Fuel: An Assessment

Energy Technology Data Exchange (ETDEWEB)

Meyer, Ryan M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Pardini, Allan F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cuta, Judith M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Adkins, Harold E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Casella, Andrew M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Qiao, Hong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Larche, Michael R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Diaz, Aaron A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Doctor, Steven R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2013-09-01

This report documents efforts to assess representative horizontal (Transuclear NUHOMS®) and vertical (Holtec HI-STORM) storage systems for the implementation of non-destructive examination (NDE) methods or techniques to manage atmospheric stress corrosion cracking (SCC) in canisters for dry storage of used nuclear fuel. The assessment is conducted by assessing accessibility and deployment, environmental compatibility, and applicability of NDE methods. A recommendation of this assessment is to focus on bulk ultrasonic and eddy current techniques for direct canister monitoring of atmospheric SCC. This assessment also highlights canister regions that may be most vulnerable to atmospheric SCC to guide the use of bulk ultrasonic and eddy current examinations. An assessment of accessibility also identifies canister regions that are easiest and more difficult to access through the ventilation paths of the concrete shielding modules. A conceivable sampling strategy for canister inspections is to sample only the easiest to access portions of vulnerable regions. There are aspects to performing an NDE inspection of dry canister storage system (DCSS) canisters for atmospheric SCC that have not been addressed in previous performance studies. These aspects provide the basis for recommendations of future efforts to determine the capability and performance of eddy current and bulk ultrasonic examinations for atmospheric SCC in DCSS canisters. Finally, other important areas of investigation are identified including the development of instrumented surveillance specimens to identify when conditions are conducive for atmospheric SCC, characterization of atmospheric SCC morphology, and an assessment of air flow patterns over canister surfaces and their influence on chloride deposition.

SCC: Semantic Context Cascade for Efficient Action Detection

KAUST Repository

Heilbron, Fabian Caba; Barrios, Wayner; Escorcia, Victor; Ghanem, Bernard

2017-01-01

in videos. Existing approaches have mitigated the computational cost, but still, these methods lack rich high-level semantics that helps them to localize the actions quickly. In this paper, we introduce a Semantic Cascade Context (SCC) model that aims

Influence of Recycled Concrete Dust on the Properties of Self– Compacting Concrete (SCC)

OpenAIRE

Ivanauskas, Ernestas; Lazauskas, Mantas; Grigaliūnas, Paulius

2017-01-01

Concrete – composite material which economical effect mostly depends on the amount of binder material (usually cement), its type and fineness. Cement manufacturing generates great employment of energy resources. The demand for all kind of manufacturing natural resources are aimed to be reduced as much as possible. Alternative raw material resources are being introduced and tested together with increasing self-compacting concrete (SCC) popularity in Lithuania. Considering environmental require...

SCC susceptibility of cold-worked stainless steel with minor element additions

Energy Technology Data Exchange (ETDEWEB)

Nakano, Junichi, E-mail: nakano.junnichi@jaea.go.jp [Japan Atomic Energy Agency, Shirakatashirane 2-4, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Nemoto, Yoshiyuki, E-mail: yoshiyuki.nemoto@oecd.org [OECD Nuclear Energy Agency, Le Seine St-Germain, 12, boulevard des Iles, F-92130 Issy-les-Moulineaux (France); Tsukada, Takashi, E-mail: tsukada.takashi@jaea.go.jp [Japan Atomic Energy Agency, Shirakatashirane 2-4, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Uchimoto, Tetsuya, E-mail: uchimoto@ifs.tohoku.ac.jp [Tohoku University, Aoba-ku, Sendai-shi, Miyagi-ken 980-8577 (Japan)

2011-10-01

To examine the effects of minor elements on stress corrosion cracking (SCC) susceptibility of low carbon stainless steels with a work hardened layer, a high purity type 304 stainless steel was fabricated and minor elements, Si, S, P, C or Ti, were added. A work hardened layer was introduced by shaving on the surface of stainless steels. The specimens were exposed to a boiling 42% MgCl{sub 2} solution for 20 h and the number and the length of initiated cracks were examined. SCC susceptibility of the specimen with P was the highest and that of the specimen with C was the lowest in all specimens. By magnetic force microscope examination, a magnetic phase expected to be a martensitic phase was detected near the surface. Since corrosion resistance of martensite is lower than that of austenite, the minor elements additions would affect SCC susceptibility through the amount of the transformed martensite.

Estimation of radiative forcing and chore length of shallow convective clouds (SCC) based on broadband pyranometer measurement network

Science.gov (United States)

Shi, H.

2017-12-01

We presented a method to identify and calculate cloud radiative forcing (CRF) and horizontal chore length (L) of shallow convective clouds (SCC) using a network of 9 broadband pyranometers. The analyzing data was collected from the SCC campaign during two years summers (2015 2016) at Baiqi site over Inner Mongolia grassland. The network of pyranometers was operated across a spatial domain covering 42.16-42.30° N and 114.83-114.98° E. The SCC detection method was verified by observer reports and cameras, which showed that the detection method and human observations were in agreement about 75 %. The differences between the SCC detection method and human observations can be responsible for following factors: 1) small or dissipating clouds can be neglected for the value of 1 min of temporal resolution of pyranometer; 2) human observation recorded weather conditions four times every day; 3) SCC was indistinguishable from coexistence of SCC and Cirrus (Ci); 4) the SCC detection method is weighted toward clouds crossing the sun's path, while the human observer can view clouds over the entire sky. The deviation of L can be attributed to two factors: 1) the accuracy of wind speed at height of SCC and the ratio of horizontal and vertical length play a key role in determine values of L; 2) the effect of variance of solar zenith angle can be negligible. The downwelling shortwave CRF of SCC was -134.1 Wm-2. The average value of L of SCC was 1129 m. Besides, the distribution of normalized cloud chore length agreed well with power-law fit.

Isoalantolactone inhibits UM-SCC-10A cell growth via cell cycle arrest and apoptosis induction.

Directory of Open Access Journals (Sweden)

Minjun Wu

Full Text Available Isoalantolactone is a sesquiterpene lactone compound isolated from the roots of Inula helenium L. Previous studies have demonstrated that isoalantolactone possesses antifungal, anti-bacterial, anti-helminthic and anti-proliferative properties in a variety of cells, but there are no studies concerning its effects on head and neck squamous cell carcinoma (HNSCC. In the present study, an MTT assay demonstrated that isoalantolactone has anti-proliferative activity against the HNSCC cell line (UM-SCC-10A. Immunostaining identified that this compound induced UM-SCC-10A cell apoptosis but not necrosis. To explain the molecular mechanisms underlying its effects, flow cytometry and western blot analysis showed that the apoptosis was associated with cell cycle arrest during the G1 phase, up-regulation of p53 and p21, and down-regulation of cyclin D. Furthermore, our results revealed that induction of apoptosis through a mitochondrial pathway led to up-regulation of pro-apoptotic protein expression (Bax, down-regulation of anti-apoptotic protein expression (Bcl-2, mitochondrial release of cytochrome c (Cyto c, reduction of mitochondrial membrane potential (MMP and activation of caspase-3 (Casp-3. Involvement of the caspase apoptosis pathway was confirmed using caspase inhibitor Z-VAD-FMK pretreatment. Together, our findings suggest that isoalantolactone induced caspase-dependent apoptosis via a mitochondrial pathway and was associated with cell cycle arrest in the G1 phase in UM-SCC-10A cells. Therefore, isoalantolactone may become a potential drug for treating HNSCC.

Learnings from investigations on SG divider plates: Coupling field characterizations with numerical mechanical simulation

International Nuclear Information System (INIS)

Rossillon, F.; Depradeux, L.; Miloudi, S.; Deforge, D.; Lemaire, E.; Massoud, J.P.

2014-01-01

Nickel based alloys stress corrosion cracking (SCC) has been a major concern for the nuclear power plant utilities since the 1970s. Since 2002, SCC indications have been found on steam generator (SG) divider plates made of alloy 600 on French PWRs (pressurized water reactors) 900 MWe units. Although integrity is not questioned, many studies have been conducted to deepen understanding of the phenomenon. Among numerous studies to investigate the SCC damage phenomena, advanced mechanical analysis has been performed to improve the knowledge of the in-service loadings of the SG 900 MWe partition stub and divider plate. Manufacturing steps are taken into account, such as welding and the first hydro-test, to have a more precise description of the mechanical states in the vicinity of the welds where SCC is likely to occur. Recently, EDF hot laboratories made destructive examinations of a decommissioned SG. To fulfil the analyses computations have been carried out on the dedicated configuration. A 3D FE model, including the simulation of the welding and hydro-test, has been set up. Comparisons with experimental investigations on the divider plate of decommissioned SG have shown a good agreement between experimental and numerical results. These results emphasize the redistribution of weld residual stresses after the first hydro-test, and the effect of hydro-testing on the plastic deformation of the stub only in some specific cases of 900 MWe SG

Learnings from investigations on SG divider plates: Coupling field characterizations with numerical mechanical simulation

Energy Technology Data Exchange (ETDEWEB)

Rossillon, F., E-mail: frederique.rossillon@edf.fr [EDF SEPTEN, 12-14 Avenue Dutrievoz, Villeurbanne (France); Depradeux, L. [EC2-MS, 66 Bd Niels Bohr, Villeurbanne (France); Miloudi, S. [EDF CEIDRE, CNPE de Chinon, Avoine (France); Deforge, D. [EDF CEIDRE, 2 Rue Ampère, Saint Denis (France); Lemaire, E. [EDF UNIE, Cap Ampère, Saint Denis (France); Massoud, J.P. [EDF SEPTEN, 12-14 Avenue Dutrievoz, Villeurbanne (France)

2014-04-01

Nickel based alloys stress corrosion cracking (SCC) has been a major concern for the nuclear power plant utilities since the 1970s. Since 2002, SCC indications have been found on steam generator (SG) divider plates made of alloy 600 on French PWRs (pressurized water reactors) 900 MWe units. Although integrity is not questioned, many studies have been conducted to deepen understanding of the phenomenon. Among numerous studies to investigate the SCC damage phenomena, advanced mechanical analysis has been performed to improve the knowledge of the in-service loadings of the SG 900 MWe partition stub and divider plate. Manufacturing steps are taken into account, such as welding and the first hydro-test, to have a more precise description of the mechanical states in the vicinity of the welds where SCC is likely to occur. Recently, EDF hot laboratories made destructive examinations of a decommissioned SG. To fulfil the analyses computations have been carried out on the dedicated configuration. A 3D FE model, including the simulation of the welding and hydro-test, has been set up. Comparisons with experimental investigations on the divider plate of decommissioned SG have shown a good agreement between experimental and numerical results. These results emphasize the redistribution of weld residual stresses after the first hydro-test, and the effect of hydro-testing on the plastic deformation of the stub only in some specific cases of 900 MWe SG.

Distinguishing effect of buffing vs. grinding, milling and turning operations on the chloride induced SCC susceptibility of 304L austenitic stainless steel

International Nuclear Information System (INIS)

Kumar, Pandu Sunil; Acharyya, Swati Ghosh; Rao, S.V. Ramana; Kapoor, Komal

2017-01-01

The study compares the effect of different surface working operations like grinding, milling, turning and buffing on the Cl – induced stress corrosion cracking (SCC) susceptibility of austenitic 304L stainless steel (SS) in a chloride environment. SS 304L was subjected to four different surface working operations namely grinding, milling, turning and buffing. The residual stress distribution of the surface as a result of machining was measured by X-ray diffraction. The Cl – induced SCC susceptibility of the different surface worked samples were determined by testing in boiling magnesium chloride as per ASTM G36 for 3 h, 9 h and 72 h. The surface and cross section of the samples both pre and post exposure to the corrosive medium was characterized using optical microscopy, scanning electron microscopy (SEM). The study revealed that grinding, milling and turning operations resulted in high tensile residual stresses on the surface together with the high density of deformation bands making these surfaces highly susceptible to Cl – induced SCC. On the other hand buffing produces compressive residual stresses on the surface with minimal plastic strain, making it more resistance to Cl – induced SCC. The study highlights that the conventional machining operations on 304L SS surfaces should be invariably followed by buffing operation to make the surfaces more resistance to SCC. - Highlights: • Grinding, milling and turning lead to tensile residual stresses and plastic strain. • Buffing leads to compressive residual stresses on the surface and minimal strain. • Grinding, milling and turning make 304L SS surface susceptible to SCC. • Buffed 304L SS surface is immune to SCC. • Grinding, milling, and turning operations should be followed by buffing operation.

Distinguishing effect of buffing vs. grinding, milling and turning operations on the chloride induced SCC susceptibility of 304L austenitic stainless steel

Energy Technology Data Exchange (ETDEWEB)

Kumar, Pandu Sunil [School of Engineering Sciences and Technology, University of Hyderabad, Hyderabad 500046 (India); Acharyya, Swati Ghosh, E-mail: swati364@gmail.com [School of Engineering Sciences and Technology, University of Hyderabad, Hyderabad 500046 (India); Rao, S.V. Ramana; Kapoor, Komal [Nuclear Fuel Complex, Department of Atomic Energy, Government of India, Hyderabad 500062 (India)

2017-02-27

The study compares the effect of different surface working operations like grinding, milling, turning and buffing on the Cl{sup –} induced stress corrosion cracking (SCC) susceptibility of austenitic 304L stainless steel (SS) in a chloride environment. SS 304L was subjected to four different surface working operations namely grinding, milling, turning and buffing. The residual stress distribution of the surface as a result of machining was measured by X-ray diffraction. The Cl{sup –} induced SCC susceptibility of the different surface worked samples were determined by testing in boiling magnesium chloride as per ASTM G36 for 3 h, 9 h and 72 h. The surface and cross section of the samples both pre and post exposure to the corrosive medium was characterized using optical microscopy, scanning electron microscopy (SEM). The study revealed that grinding, milling and turning operations resulted in high tensile residual stresses on the surface together with the high density of deformation bands making these surfaces highly susceptible to Cl{sup –} induced SCC. On the other hand buffing produces compressive residual stresses on the surface with minimal plastic strain, making it more resistance to Cl{sup –} induced SCC. The study highlights that the conventional machining operations on 304L SS surfaces should be invariably followed by buffing operation to make the surfaces more resistance to SCC. - Highlights: • Grinding, milling and turning lead to tensile residual stresses and plastic strain. • Buffing leads to compressive residual stresses on the surface and minimal strain. • Grinding, milling and turning make 304L SS surface susceptible to SCC. • Buffed 304L SS surface is immune to SCC. • Grinding, milling, and turning operations should be followed by buffing operation.

SCC modification by use of amorphous nano-silica

NARCIS (Netherlands)

Quercia Bianchi, G.; Spiesz, P.R.; Hüsken, G.; Brouwers, H.J.H.

2014-01-01

In this study two different types of nano-silica (nS) were applied in self-compacting concrete (SCC), both having similar particle size distributions (PSD), but produced through two different processes: fumed powder silica and precipitated silica in colloidal suspension. The influence of nano-silica

Form Filling with SCC in a Vertical Form

DEFF Research Database (Denmark)

Thrane, Lars Nyholm

2004-01-01

This paper presents the results obtained from two different vertical form filling experiments with SCC that have been completed as part of the experimental work in an ongoing Ph.D project. The project is carried out at the Danish Technological Institute in collaboration with the Technical...

Inducement of IGA/SCC in Inconel 600 steam generator tubing during unit outages

Energy Technology Data Exchange (ETDEWEB)

Durance, D.; Sedman, K. [Bruce Power, Tiverton, Ontario (Canada); Roberts, J. [CANTECH Associates Ltd., Burlington, Ontario (Canada); King, P. [Babcock and Wilcox Canada, Cambridge, Ontario (Canada); Gorman, J. [Dominion Engineering, Reston, VA (United States); Allen, R. [Kinectrics, Inc., Toronto, Ontario (Canada)

2008-07-01

The degradation of Unit 4 SG tubing by IGA/SCC has limited both the operating period and end of life predictions for Unit 4 since restart in late 2003. The circumferential IGA/SCC has been most significant in SG4 with substantial increases in both initiation and growth rates from 2005 through the spring of 2007. A detailed review of the occurrence of circumferential OD IGA/SCC at the RTZ in the HL TTS region of Bruce 4 steam generator tubes has led a conclusion that it is probable that the IGA/SCC has been the result of attack by partially reduced sulfur species such as tetrathionates and thiosulfates during periods of low temperature exposure. It is believed that attack of this type has mostly likely occurred during startup evolutions following outages as the result the development of aggressive reduced sulfur species in the TTS region during periods when the boilers were fully drained for maintenance activities. The modification of outage practices to limit secondary side oxygen ingress in the spring of 2007 has apparently arrested the degradation and has had significant affects on the allowable operating interval and end of life predictions for the entire unit. (author)

Inducement of IGA/SCC in Inconel 600 steam generator tubing during unit outages

International Nuclear Information System (INIS)

Durance, D.; Sedman, K.; Roberts, J.; King, P.; Gorman, J.; Allen, R.

2008-01-01

The degradation of Unit 4 SG tubing by IGA/SCC has limited both the operating period and end of life predictions for Unit 4 since restart in late 2003. The circumferential IGA/SCC has been most significant in SG4 with substantial increases in both initiation and growth rates from 2005 through the spring of 2007. A detailed review of the occurrence of circumferential OD IGA/SCC at the RTZ in the HL TTS region of Bruce 4 steam generator tubes has led a conclusion that it is probable that the IGA/SCC has been the result of attack by partially reduced sulfur species such as tetrathionates and thiosulfates during periods of low temperature exposure. It is believed that attack of this type has mostly likely occurred during startup evolutions following outages as the result the development of aggressive reduced sulfur species in the TTS region during periods when the boilers were fully drained for maintenance activities. The modification of outage practices to limit secondary side oxygen ingress in the spring of 2007 has apparently arrested the degradation and has had significant affects on the allowable operating interval and end of life predictions for the entire unit. (author)

The effect of form pressure on the air void structure of SCC

DEFF Research Database (Denmark)

Jensen, Mikkel Vibæk; Hasholt, Marianne Tange; Geiker, Mette Rica

2005-01-01

The high workability of self-compacting concrete (SCC) invites to high casting rates. However, casting walls at high rate may result in large pressure at the bottom of the form and subsequently compression of the air voids. This paper deals with the influence of hydrostatic pressure during setting...... on the air void structure of hardened, air entrained SCC. The subject was examined through laboratory investigations of SCC with two different amounts of air entrainment. The condition in the form was simulated by using containers making it possible to cure concrete under various pressures corresponding...... to the bottom of castings of 0, 2, 4, and 6 meters height. The laboratory investigations were supplemented with data from two full-scale wall castings. The air void structure of the hardened concretes was determined on plane sections. The results indicate that the pressure related changes of the air void...

Influence of surface oxide films on the SCC of stainless steel in high temperature water

Energy Technology Data Exchange (ETDEWEB)

Tani, Junichi; Kato, Shunji; Hirano, Hideo [Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan). Komae Research Lab; Kushida, H.

2000-06-01

Effect of pre-filming conditions on the SCC susceptibility of stainless steels (SS) was investigated by SSRT and electrochemical measurement in high temperature water. The IGSCC ratio of a specimen with the oxide film formed in hydrogen-saturated water (R film specimen) was higher than that of a specimen with the oxide film formed in air-saturated water (O film specimen). When the pre-filmed specimens were coupled with a Cr-depleted SS that simulated weld-heat-affected zones, the galvanic couple between the R film specimen and Cr-depleted SS showed higher corrosion current than the couple between the O film specimen and Cr-depleted SS. The film thickness of the Cr-depleted SS was thinner in the couple with the R film specimen after the test. These results clearly show that the SCC susceptibility of R film specimen was higher than that of the O film specimen, in accordance with the SSRT results. (author)

SRNL SHELF LIFE STUDIES - SCC STUDIES AT ROOM TEMPERTURE [stress corrosion cracking

Energy Technology Data Exchange (ETDEWEB)

Mickalonis, J.; Duffey, J.

2014-11-12

Phase II, Series 2 corrosion testing performed by the Savannah River National Laboratory (SRNL) for the Department of Energy 3013 container has been completed. The corrosion tests are part of an integrated plan conducted jointly by Los Alamos National Laboratory and the Savannah River Site. SRNL was responsible for conducting corrosion studies in small-scale vessels to address the influence of salt composition, water loading, and type of oxide/salt contact on the relative humidity inside a 3013 container and on the resulting corrosion of Type 304L and 316L stainless steel (304L and 316L). This testing was conducted in two phases: Phase I evaluated a broad spectrum of salt compositions and initial water loadings on the salt mixtures exposed to 304L and 316L and the resulting corrosion; Phase II evaluated the corrosion of 304L at specific water loadings and a single salt composition. During Phase I testing at high initial moisture levels (0.35 to 1.24 wt%)a, the roomtemperature corrosion of 304L exposed to a series of plutonium oxide/chloride salt mixtures ranged from superficial staining to pitting and stress corrosion cracking (SCC). 304L teardrop coupons that exhibited SCC were directly exposed to a mixture composed of 98 wt % PuO2, 0.9 wt % NaCl, 0.9 wt % KCl, and 0.2 wt % CaCl2. Cracking was not observed in a 316L teardrop coupon. Pitting was also observed in this environment for both 304L and 316L with depths ranging from 20 to 100 μm. Neither pitting nor SCC was observed in mixtures with a greater chloride salt concentration (5 and 28 wt%). These results demonstrated that for a corrosive solution to form a balance existed between the water loading and the salt chloride concentration. This chloride solution results from the interaction of loaded water with the hydrating CaCl2 salt. In Phase II, Series 1 tests, the SCC results were shown to be reproducible with cracking occurring in as little as 85 days. The approximate 0.5 wt% moisture level was found to

Grain by grain study of the mechanisms of crack propagation during iodine SCC of Zry-4

International Nuclear Information System (INIS)

Haddad Andalag, R.E.

1993-01-01

This paper describes the tests conducted to determine the conditions leading to cracking of a specified grain of metal, focussing on the crystallographic orientation of crack paths, the critical stress conditions and the significance of the fractographic features encountered. In order to get orientable cracking, a technique was developed to produce iodine SCC, by means of pressurizing tubes of a specially heat treated Zry-4 having very large grains, shaped as discs of a few millimeters in diameter and grown up to the wall thickness. Careful orientation of fractured grains, performed by means of a back-reflection Laue technique with a precision better than one degree, has proved that transgranular cracking occurs only along basal planes. The effect of anisotropy, plasticity, triaxiality and residual stresses originated in thermal contraction, has to be considered to account for the influence of the stress state . A grain by grain calculation led to the conclusion that transgranular cracking always occurs on those bearing the maximum resolved tensile stress on basal planes. There are clear indications of the need of a triaxial stress state for the process to occur. Fracture modes other than pseudo-cleavage have been encountered, including intergranular separation, ductile tearing produced by prismatic slip and propagation along twin boundaries. In each case the fractographic features have been identified, and associations have been made with fractographs obtained in normal fuel cladding. (Author)

Effects of overload on the threshold stress intensity factor for SCC

International Nuclear Information System (INIS)

Takahashi, Koji; Ando, Kotoji; Miyazaki, Yuji; Hashikura, Yasuaki

2009-01-01

The effects of overload on the threshold stress intensity factor for stress corrosion crack (K ISCC ) of stainless steel were studied. Tensile overload was applied to a wedge opening loaded (WOL) specimen of SUS316. Then, SCC tests were carried out to determine the resultant K ISCC . As a result, the apparent value of K ISCC increases as increasing a stress intensity factor by tensile overload (K OV ). The effects of tensile overload on K ISCC and the threshold stress intensity factor range for fatigue (ΔK th ) were compared. It was found that the effects of tensile overload on K ISCC were larger than that on ΔK th . (author)

Role of grain boundary engineering in the SCC behavior of ferritic-martensitic alloy HT-9

International Nuclear Information System (INIS)

Gupta, G.; Ampornrat, P.; Ren, X.; Sridharan, K.; Allen, T.R.; Was, G.S.

2007-01-01

This paper focuses on the role of grain boundary engineering (GBE) in stress corrosion cracking (SCC) of ferritic-martensitic (F-M) alloy HT-9 in supercritical water (SCW) at 400 deg. C and 500 deg. C. Constant extension rate tensile (CERT) tests were conducted on HT-9 in as-received (AR) and coincident site lattice enhanced (CSLE) condition. Both unirradiated and irradiated specimens (irradiated with 2 MeV protons at 400 deg. C and 500 deg. C to a dose of 7 dpa) were tested. Ferritic-martensitic steel HT-9 exhibited intergranular stress corrosion cracking when subjected to CERT tests in an environment of supercritical water at 400 deg. C and 500 deg. C and also in an inert environment of argon at 500 deg. C. CSL-enhancement reduces grain boundary carbide coarsening and cracking susceptibility in both the unirradiated and irradiated condition. Irradiation enhanced coarsening of grain boundary carbides and cracking susceptibility of HT-9 for both the AR and CSLE conditions. Intergranular (IG) cracking of HT-9 results likely from fracture of IG carbides and seems consistent with the mechanism that coarser carbides worsen cracking susceptibility. Oxidation in combination with wedging stresses is the likely cause of the observed environmental enhancement of high temperature IG cracking in HT-9

Cytotoxic Effect of the Genus Sinularia Extracts on Human SCC25 and HaCaT Cells

International Nuclear Information System (INIS)

Wang, G.H.; Chou, T.H.; Liang, C.H.; Lin, R.J.; Sheu, J.H.; Wang, S.H.

2009-01-01

Soft corals of the genus Sinularia are being increasingly adopted to treat a wide variety of disease processes. However, the mechanism underlying its activity against human oral cancer cells is poorly understood. This study evaluates the cyototoxicity effects of the genus Sinularia extracts (S. grandilobata, S. parva, S. triangula, S. scabra, S. nanolobata and S. gibberosa) by SCC25 and HaCaT cells. The cell adhesion assay indicates that extracts reduce the cell attachment. Extracts exhibit a dose-dependent cytotoxic effect using MTS assay.Treatment of extracts to observe the morphological alterations in cells, membrane blebbing, nuclear condensation, and apoptotic bodies is demonstrated. Flow cytometry shows that extracts sensitized the cells in the G0/G1 and G2/M phases with a concomitant significantly increased sub-G1 fraction, suggesting cell death by apoptosis. Extracts of the genus Sinularia thus apparently cause apoptosis of SCC25 and HaCaT cells, and warrant further research investigating the possible antioral cancer compounds in these soft corals.

Characteristics of SCC crack propagation in 22Cr-5. 5Ni-3Mo duplex stainless steel weldment

Energy Technology Data Exchange (ETDEWEB)

Kim, Choong Un; Kang, Choon Sik

1988-02-01

The characteristics of SCC crack propagation in duplex stainless steel weldment made by SMAW, GTAW and GMAW processes were investigated in 42% MgCl/sub 2/ 142 deg C boiling solution. From these experiments, it could be concluded that the structure anisotropy of ..gamma.. phase as well as the phase ratio played an important role in SCC resistance. GTA and GMA weld metal showed higher SCC resistance than base metal because of randomly distributed ..gamma.. phase. The crack in weld metal had same opportunity of receiving keying effect as that in base metal, but it had less possibility of intersecting ..gamma.. phase. The SCC resistance of the SMA weld metal and the HAZ was lower than that of the base metal because their phase ratio deviated from the proper phase ratio.

Porosity of Self-Compacting Concrete (SCC) incorporating high volume fly ash

Science.gov (United States)

Kristiawan, S. A.; Sunarmasto; Murti, G. Y.

2017-02-01

Degradation of concrete could be triggered by the presence of aggressive agents from the environment into the body of concrete. The penetration of these agents is influenced by the pore characteristics of the concrete. Incorporating a pozzolanic material such as fly ash could modify the pore characteristic of the concrete. This research aims to investigate the influence of incorporating fly ash at high volume level on the porosity of Self-Compacting Concrete (SCC). Laboratory investigations were carried out following the ASTM C642 for measuring density and volume of permeable pores (voids) of the SCC with varying fly ash contents (50-70% by weight of total binder). In addition, a measurement of permeable voids by saturation method was carried out to obtain an additional volume of voids that could not be measured by the immersion and boiling method of ASTM C642. The results show that the influence of fly ash content on the porosity appears to be dependent on age of SCC. At age less than 56 d, fly ash tends to cause an increase of voids but at 90 d of age it reduces the pores. The additional pores that can be penetrated by vacuum saturation method counts about 50% of the total voids.

A criterion and mechanism for power ramp defects

International Nuclear Information System (INIS)

Garlick, A.; Gravenor, J.G.

1978-02-01

The problem of power ramp defects in water reactor fuel pins is discussed in relation to results recently obtained from ramp experiments in the Steam Generating Heavy Water Reactor. Cladding cracks in the defected fuel pins were similar, both macro- and micro structurally, to those in unirradiated Zircaloy exposed to iodine stress-corrosion cracking (scc) conditions. Furthermore, when the measured stress levels for scc in short-term tests were taken as a criterion for ramp defects, UK fuel modelling codes were found to give a useful indication of defect probability under reactor service conditions. The likelihood of sticking between fuel and cladding is discussed and evidence presented which suggests that even at power a degree of adhesion may be expected in some fuel pins. The ramp defect mechanism is discussed in terms of fission product scc, initiation being by intergranular penetration and propagation by cleavage when suitably orientated grains are exposed to large dilatational stresses ahead of the main crack. (author)

Multiple nano elements of SCC--transition from phenomenology to predictive mechanistics

International Nuclear Information System (INIS)

Staehle, R.W.

2009-01-01

Full text of publication follows: Predicting the occurrence and rate of stress corrosion cracking in materials of construction is one of the most critical pathways for assuring the reliability of light water nuclear reactor plants. It is the general intention of operators of nuclear plants that they continue performing satisfactorily for times of 60 to 80 years at least. Such times are beyond existing experience, and there are no bases for choosing credible predictions. Present bases for predicting SCC rely on anecdotal experience for predicting what materials sustain SCC in specified environments and on phenomenological correlations using such parameters as K (stress intensity), 1/T (temperature), E(corr) (corrosion potential), pH, [x] a (concentration), other established quantities, and statistical correlations. While these phenomenological correlations have served the industry well in the past, they have also allowed grievous mistakes. Further, such correlations are flawed in their fundamental credibility. Predicting SCC in aqueous solutions means to predict its dependence upon the seven primary variables: potential, pH, species, alloy composition, alloy structure, stress and temperature. A serious prediction of SCC upon these seven primary variables can only be achieved by moving to fundamental nano elements. Unfortunately, useful predictability from the nano approach cannot be achieved quickly or easily; thus, it will continue to be necessary to rely on existing phenomenology. However, as the nano approach evolves, it can contribute increasingly to the quantitative capacity of the phenomenological approach. The nano approach will require quite different talents and thinking than are now applied to the prediction of SCC; while some of the boundary conditions of phenomenology must continue to be applied, elements of the nano approach will include accounting for at least, typically, the following multiple elements as they apply at the sites of initiation and at

Usefulness of SCC-antigen for diagnosis and monitoring recurrence and effectiveness of therapies of squamous cell carcinoma of the lung

International Nuclear Information System (INIS)

Mino, Naoko; Iio, Atsushi; Ata, Mariko; Murase, Kenya; Kataoka, Masaaki; Ito, Hisao; Ishine, Masahiro; Kawamura, Masashi; Hamamoto, Ken

1987-01-01

The serum levels of SCC antigen (squamous cell carcinoma related antigen) were measured in 111 patients with primary lung cancer to assess its clinical usefulness for diagnosis of squamous cell carcinoma and for monitoring recurrence and effectiveness of therapies. Serum SCC antigen level in patients with squamous cell carcinoma of the lung was 5.9 ± 10.4 ng/ml, which was high (p < 0.05) compared with those in normal controls (1.6 ± 0.5 ng/ml), patients with other types of lung cancer (2.4 ± 2.9 ng/ml) or benign disease (1.8 ± 1.1 ng/ml). Studies at various clinical stages of squamous cell carcinoma of the lung showed, however, that the SCC antigen levels were high only in the advanced stages (III and IV), whereas not so high in the earlier stages. These results confirmed that SCC antigen is a relatively specific marker to squamous cell carcinoma in the lung, as reported in the uterine cervix and the esophagus. The SCC antigen levels decreased after operation and more markedly after radiotherapy in dose-dependent manner, corresponding to the reduction of the tumor size. On the other hand, the SCC antigen levels were extremely high in the recurrence. It was concluded that SCC antigen is a useful marker for monitoring recurrence or effectiveness of the therapies of SCC of the lung, although not so for its early diagnosis. (author)

Curcumin inhibits oral squamous cell carcinoma SCC-9 cells proliferation by regulating miR-9 expression

Energy Technology Data Exchange (ETDEWEB)

Xiao, Can [Department of Occupational Medicine and Environmental Health, School of Public Health, Soochow University, Suzhou 215123 (China); Department of Stomatology, The First Affiliated Hospital of Soochow University, Suzhou 215006 (China); Wang, Lili; Zhu, Lifang [Department of Stomatology, The First Affiliated Hospital of Soochow University, Suzhou 215006 (China); Zhang, Chenping, E-mail: zhang_cping@163.com [Department of Head and Neck Tumors, Shanghai Ninth People’s Hospital Affiliated Shanghai JiaoTong University School of Medicine, Shanghai 200011 (China); Zhou, Jianhua [Department of Occupational Medicine and Environmental Health, School of Public Health, Soochow University, Suzhou 215123 (China)

2014-11-28

Highlights: • miR-9 expression level was significantly decreased in OSCC tissues. • Curcumin significantly inhibited SCC-9 cells proliferation. • miR-9 mediates the inhibition of SCC-9 proliferation by curcumin. • Curcumin suppresses Wnt/β-catenin signaling in SCC-9 cells. • miR-9 mediates the suppression of Wnt/β-catenin signaling by curcumin. - Abstract: Curcumin, a phytochemical derived from the rhizome of Curcuma longa, has shown anticancer effects against a variety of tumors. In the present study, we investigated the effects of curcumin on the miR-9 expression in oral squamous cell carcinoma (OSCC) and explored the potential relationships between miR-9 and Wnt/β-catenin pathway in curcumin-mediated OSCC inhibition in vitro. As the results shown, the expression levels of miR-9 were significantly lower in clinical OSCC specimens than those in the adjacent non-tumor tissues. Furthermore, our results indicated that curcumin inhibited OSCC cells (SCC-9 cells) proliferation through up-regulating miR-9 expression, and suppressing Wnt/β-catenin signaling by increasing the expression levels of the GSK-3β, phosphorylated GSK-3β and β-catenin, and decreasing the cyclin D1 level. Additionally, the up-regulation of miR-9 by curcumin in SCC-9 cells was significantly inhibited by delivering anti-miR-9 but not control oligonucleotides. Downregulation of miR-9 by anti-miR-9 not only attenuated the growth-suppressive effects of curcumin on SCC-9 cells, but also re-activated Wnt/β-catenin signaling that was inhibited by curcumin. Therefore, our findings would provide a new insight into the use of curcumin against OSCC in future.

Curcumin inhibits oral squamous cell carcinoma SCC-9 cells proliferation by regulating miR-9 expression

International Nuclear Information System (INIS)

Xiao, Can; Wang, Lili; Zhu, Lifang; Zhang, Chenping; Zhou, Jianhua

2014-01-01

Highlights: • miR-9 expression level was significantly decreased in OSCC tissues. • Curcumin significantly inhibited SCC-9 cells proliferation. • miR-9 mediates the inhibition of SCC-9 proliferation by curcumin. • Curcumin suppresses Wnt/β-catenin signaling in SCC-9 cells. • miR-9 mediates the suppression of Wnt/β-catenin signaling by curcumin. - Abstract: Curcumin, a phytochemical derived from the rhizome of Curcuma longa, has shown anticancer effects against a variety of tumors. In the present study, we investigated the effects of curcumin on the miR-9 expression in oral squamous cell carcinoma (OSCC) and explored the potential relationships between miR-9 and Wnt/β-catenin pathway in curcumin-mediated OSCC inhibition in vitro. As the results shown, the expression levels of miR-9 were significantly lower in clinical OSCC specimens than those in the adjacent non-tumor tissues. Furthermore, our results indicated that curcumin inhibited OSCC cells (SCC-9 cells) proliferation through up-regulating miR-9 expression, and suppressing Wnt/β-catenin signaling by increasing the expression levels of the GSK-3β, phosphorylated GSK-3β and β-catenin, and decreasing the cyclin D1 level. Additionally, the up-regulation of miR-9 by curcumin in SCC-9 cells was significantly inhibited by delivering anti-miR-9 but not control oligonucleotides. Downregulation of miR-9 by anti-miR-9 not only attenuated the growth-suppressive effects of curcumin on SCC-9 cells, but also re-activated Wnt/β-catenin signaling that was inhibited by curcumin. Therefore, our findings would provide a new insight into the use of curcumin against OSCC in future

Assessment of copper resistance to stress-corrosion cracking in nitrite solutions by means of joint analysis of acoustic emission measurements, deformation diagrams, qualitative and quantitative fractography, and non-linear fracture mechanics

Energy Technology Data Exchange (ETDEWEB)

Khanzhin, V.G.; Nikulin, S.A. [Moscow State Inst. of Steel and Alloys (Russian Federation)

2005-06-01

A study of stress-corrosion cracking (SCC) of copper in 0.1M NaNO{sub 2} aqueous solution is presented. The fracture kinetics was monitored by measuring the acoustic emission (AE) signals. Macro- and micro-fractography analysis, using scanning electron microscopy (SEM), was employed to investigate the fracture mechanisms. Estimates of stress intensity factor, KI, and J-integral were derived in order to assess the resistance of copper to stress corrosion cracking. Two kinds of SCC tests under continuous circulation of the corrosive solution were employed in the present study: 1. Constant extension rate (2x10{sup -6}/s) tests on pre-cracked, middle tension (MT) panel specimens. 2. Tests on pre-cracked, compact tension (CT) specimens at a fixed (by a fixing bolt) opening of the crack walls ({delta} = 0.3 mm, K{sub i} = 27 MPax{radical}m). The time base for these tests was about two months. After the completion of the SCC test, the CT specimen was additionally tested, under a constant-rate (0.02 mm/s) off-center extension. In the both kinds of tests, the SCC fracture kinetics is found to exhibit two typical stages: Stage 1: SCC initiation stage (after a certain incubation period, T{sub i}, measured to be T{sub i} {approx_equal} 3-4 hours for MT specimens under constant extension, the corresponding stress was {sigma} {approx_equal} 40-70 MPa, and T{sub i} {approx_equal} 200 hours for CT specimens under a fixed crack wall opening). Stage 2: Active fracture process (SCC macro-fracture) distinguished by strong AE pulses (which are registered after time T{sub 2} {approx_equal} 8 hours for MT specimens and T{sub 2} {approx_equal} 800 hours for CT specimens). Fractography analysis has shown that the zone of SCC fracture in MT specimens extends to approximately 1,500 {mu}m. A 400-700 {mu}m deep zone of brittle transgranular fracture, which included small areas showing characteristic SCC 'striations', was observed adjacent to the fatigue pre-crack area. At higher

Basic evaluation of measurement of the serum level of squamous cell carcinoma-related antigen (SCC) and its value in following irradiated patients with cancer of the uterine cervix

International Nuclear Information System (INIS)

Obata, Yasunori; Tadokoro, Masanori; Kazato, Sadayuki

1987-01-01

The measuremet of the serum level of squamous cell carcinoma-related antigen (SCC) purified from liver metastasis of cancer of the uterine cervix by an RIA kit is basically evaluated. The results of sensitivity, the recovery test, dilution test and variance test are good enough for clinical application. In gynecological disorders, the possitive rate is high (62 % [29/47]) in patients with cancer of the uterine cervix. Furthermore, the rate and level are related with the clinical staging. The changes of the serum SCC level in irradiated patients with cancer of the uterine cervix were a good reflection of the effectiveness of the treatment. (author)

Blocking Mechanism Study of Self-Compacting Concrete Based on Discrete Element Method

Science.gov (United States)

Zhang, Xuan; Li, Zhida; Zhang, Zhihua

2017-11-01

In order to study the influence factors of blocking mechanism of Self-Compaction Concrete (SCC), Roussel’s granular blocking model was verified and extended by establishing the discrete element model of SCC. The influence of different parameters on the filling capacity and blocking mechanism of SCC were also investigated. The results showed that: it was feasible to simulate the blocking mechanism of SCC by using Discrete Element Method (DEM). The passing ability of pebble aggregate was superior to the gravel aggregate and the passing ability of hexahedron particles was bigger than tetrahedron particles, while the tetrahedron particle simulation results were closer to the actual situation. The flow of SCC as another significant factor affected the passing ability that with the flow increased, the passing ability increased. The correction coefficient λ of the steel arrangement (channel section shape) and flow rate γ in the block model were introduced that the value of λ was 0.90-0.95 and the maximum casting rate was 7.8 L/min.

Environmental mitigation for SCC initiation of BWR core internals by hydrogen injection during start-up

International Nuclear Information System (INIS)

Dozaki, K.; Abe, A.; Nagata, N.; Takiguchi, H.

2004-01-01

Hydrogen injection into the reactor water has been applied to many BWR power stations. Since hydrogen injected accelerates recombination of oxidant generated by water radiolysis, oxidant concentration, such as dissolved oxygen concentration in reactor water can be reduced. As the result of the reduction of oxidant concentration, Electrochemical Corrosion Potential (ECP) at the surface of structural material can be lowered. Lowered ECP moderates Stress Corrosion Cracking (SCC) sensitivity of structural materials, such as stainless steels. As usual, hydrogen injection system begins to work after the plant start-up is finished, when the condition of normal operation is established. Accordingly, Hydrogen Water Chemistry (HWC) does not cover all the period of plant operation. As far as SCC crack growth is considered, loss of HWC during plant start-up does not result in significant crack growth, because of duration of plant start-up is much shorter than that of plant normal operation, when HWC condition is being satisfied. However, the reactor water environment and load conditions during a plant start-up may contribute to the initiation of SCC. It is estimated that the core internals are subjected to the strain rate that may cause susceptibility to SCC initiation during start-up. Dissolved oxygen (DO) and hydrogen peroxide (H 2 O 2 ) has a peak, and ECP is in high levels during start-up. Therefore it is beneficial to perform hydrogen injection during start-up as well in order to suppress SCC initiation. We call it HWC During Start-up (HDS) here. (orig.)

SCC life estimation based on cracks initiated from the corrosion pits of bolting material SCM435 used in steam turbine

International Nuclear Information System (INIS)

Itoh, Hitomi; Ochi, Mayumi; Fujiwara, Isao; Momoo, Takashi

2003-01-01

Life estimation was performed for the stress corrosion cracking (SCC) that occurs in deaerated and wet hot pure steam at the bottoms of the threads of bolts made of SCM435 (equivalent to AISI 4137) used in steam turbine. SCC is believed to occur when corrosion pits are formed and grow to critical size, after which SCC is initiated and cracks propagate until the critical fracture toughness value is reached. Calculations were performed using laboratory and field data. The results showed that, for a 40mm diameter bolt with 0.2% offset strength of 820MPa, the critical crack depth for straight-front cracks was 5.4mm. The SCC life depends on the lubricant used; the SCC life estimated from this value is approximately 70,000 hours when graphite is used as a lubricant. (author)

Role of cavity formation in SCC of cold worked carbon steel in high-temperature water. Part 2. Study of crack initiation behavior

International Nuclear Information System (INIS)

Yamada, Takuyo; Aoki, Masanori; Miyamoto, Tomoki; Arioka, Koji

2013-01-01

To consider the role of cavity formation in stress corrosion cracking (SCC) of cold worked (CW) carbon steel in high-temperature water, SCC and creep growth (part 1) and initiation (part 2) tests were performed. The part 2 crack initiation tests used blunt notched compact tension (CT) type specimens of CW carbon steel exposed under the static load condition in hydrogenated pure water and in air in the range of temperatures between 360 and 450°C. Inter-granular (IG) crack initiation was observed both in water and in air even in static load condition when steel specimens had been cold worked. 1/T type temperature dependencies of initiation times were observed for CW carbon steel, and the crack initiation times in an operating pressurized heavy water reactor, PHWR (Pt Lepreau) seemed to lie on the extrapolated line of the experimental results. Cavities were identified at the grain boundaries near the bottom of a notch (highly stressed location) before cracks initiated both in water and air. The cavities were probably formed by the condensation of vacancies and they affected the bond strength of the grain boundaries. To assess the mechanism of IGSCC initiation in high temperature water, the diffusion of vacancies driven by stress gradients was studied using a specially designed CT specimen. As a model for IGSCC in CW carbon steel in high temperature water, it was concluded that the formation of cavities from the collapse of vacancies offers the best interpretation of the present data. (author)

Finite-Element Investigation of the Structural Behavior of Basalt Fiber Reinforced Polymer (BFRP- Reinforced Self-Compacting Concrete (SCC Decks Slabs in Thompson Bridge

Directory of Open Access Journals (Sweden)

Lingzhu Zhou

2018-06-01

Full Text Available The need for a sustainable development and improved whole life performance of concrete infrastructure has led to the requirement of more durable and sustainable concrete bridges alongside accurate predictive analysis tools. Using the combination of Self-Compacting Concrete (SCC with industrial by-products and fiber-reinforced polymer (FRP, reinforcement is anticipated to address the concerns of high carbon footprint and corrosion in traditional steel-reinforced concrete structures. This paper presents a numerical investigation of the structural behavior of basalt fiber-reinforced polymer (BFRP-reinforced SCC deck slabs in a real bridge, named Thompson Bridge, constructed in Northern Ireland, U.K. A non-linear finite element (FE model is proposed by using ABAQUS 6.10 in this study, which is aimed at extending the previous investigation of the field test in Thompson Bridge. The results of this field test were used to validate the accuracy of the proposed finite element model. The results showed good agreement between the test results and the numerical results; more importantly, the compressive membrane action (CMA inside the slabs could be well demonstrated by this FE model. Subsequently, a series of parametric studies was conducted to investigate the influence of different parameters on the structural performance of the deck slabs in Thompson Bridge. The results of the analyses are discussed, and conclusions on the behavior of the SCC deck slabs reinforced by BFRP bars are presented.

SCC growth behavior of cast stainless steels in high-temperature water. Influences of corrosion potential, steel type, thermal aging and cold-work

International Nuclear Information System (INIS)

Yamada, Takuyo; Terachi, Takumi; Miyamoto, Tomoki; Arioka, Koji

2011-01-01

Recent studies on crack growth rate (CGR) measurement in oxygenated high-temperature pure water conditions, such as normal water chemistry (NWC) in BWRs, using compact tension (CT) type specimens have shown that stainless steel weld metal are susceptible to stress corrosion cracking (SCC). On the other hand, the authors reported that no significant SCC growth was observed on stainless steel weld metals in PWR primary water at temperatures from 250degC to 340degC. Cast austenitic stainless steels are widely used in light water reactors, and there is a similarity between welded and cast stainless steels in terms of the microstructure of the ferrite/austenite duplex structure. However, there are a few reports giving CGR data on cast stainless steels in the BWRs and PWRs. The principal purpose of this study was to examine the SCC growth behavior of cast stainless steels in simulated PWR primary water. A second objective was to examine the effects on SCC growth in hydrogenated and oxygenated water environments at 320degC of: (1) corrosion potential; (2) steels type (Mo in alloy); (3) thermal-aging (up to 400degC x 40 kh); and (4) cold-working (10%). The results were as follows: (1) No significant SCC growth was observed on all types of cast stainless steels: aged (400degC x 40 kh) of SCS14A and SCS13A and 10% cold-working, in hydrogenated (low-potential) water at 320degC. (2) Aging at 400degC x 40 kh SCS14A (10%CW) markedly accelerated the SCC growth of cast material in high-potential water at 320degC, but no significant SCC growth was observed in the hydrogenated water, even after long-term thermal aging (400degC x 40 kh). (3) Thus, cast stainless steels have excellent SCC resistance in PWR primary water. (4) On the other hand, significant SCC growth was observed on all types of cast stainless steels: 10%CW SCS14A and SCS13A, in 8 ppm-oxygenated (high-potential) water at 320degC. (5) No large difference in SCC growth was observed between SCS14A (Mo) and SCS13A. (6) No

Mechanical properties of Self-Consolidating Concrete incorporating Cement Kiln Dust

OpenAIRE

El-Mohsen, Mostafa Abd; Anwar, Ahmed M.; Adam, Ihab A.

2015-01-01

Self-Consolidating Concrete (SCC) has been widely used in both practical and laboratory applications. Selection of its components and their ratios depends, mainly, on the target mechanical and physical properties recommended by the project consultant. Partial replacement of cement in SCC with cheap available industrial by-product could produce environmentally durable concrete with similar properties of normal concrete. In the current research, SCC was produced by blending Cement Kiln Dust (CK...

Mechanical behavior of confined self-compacting reinforced concrete circular columns under concentric axial loading

Directory of Open Access Journals (Sweden)

Fouad Khairallah

2013-12-01

Full Text Available While there is abundant research information on ordinary confined concrete, there are little data on the behavior of Self-Compacting Concrete (SCC under such condition. Due to higher shrinkage and lower coarse aggregate content of SCC compared to that of Normal Concrete (NC, its composite performance under confined conditions needs more investigation. This paper has been devoted to investigate and compare the mechanical behavior of confined concrete circular columns cast with SCC and NC under concentric axial loading. The parameters affecting are including concrete compressive strength and confinement configuration. Twenty column specimens were casted and confined using four confinement techniques, CFRP wrap, FRP tube, GFRP wrap, and spiral steel hoops. The performance of the tested column specimens is evaluated based on mode of failure, load–displacement curve, stress–strain characteristics, ultimate strength, ductility, and degree of confinement.

Metallurgical and mechanical parameters controlling alloy 718 stress corrosion cracking resistance in PWR primary water

International Nuclear Information System (INIS)

Deleume, J.

2007-11-01

Improving the performance and reliability of the fuel assemblies of the pressurized water reactors requires having a perfect knowledge of the operating margins of both the components and the materials. The choice of alloy 718 as reference material for this study is justified by the industrial will to identify the first order parameters controlling the excellent resistance of this alloy to Stress Corrosion Cracking (SCC). For this purpose, a specific slow strain rate (SSR) crack initiation test using tensile specimen with a V-shaped hump in the middle of the gauge length was developed and modeled. The selectivity of such SSR tests in simulated PWR primary water at 350 C was clearly established by characterizing the SCC resistance of nine alloy 718 thin strip heats. Regardless of their origin and in spite of a similar thermo-mechanical history, they did not exhibit the same susceptibility to SCC crack initiation. All the characterized alloy 718 heats develop oxide scale of similar nature for various exposure times to PWR primary medium in the temperature range [320 C - 360 C]. δ phase precipitation has no impact on alloy 718 SCC initiation behavior when exposed to PWR primary water, contrary to interstitial contents and the triggering of plastic instabilities (PLC phenomenon). (author)

Human papillomavirus (HPV) and Oropharyngeal Squamous Cell Carcinoma (OP-SCC) of the Head and Neck: a Growing Epidemic

Science.gov (United States)

Bauman, Jessica; Wirth, Lori

2015-01-01

Human papillomavirus (HPV) is now considered a major causative agent in oropharyngeal squamous cell carcinoma (OP-SCC). The incidence of HPV+ OP-SCC is increasing dramatically, is higher in men, and is now more common than cervical cancer in the United States. HPV+ OPSCCs usually present as locally advanced, stage IV cancers, requiring intensive treatment with surgery, chemotherapy, and/or radiation that can cause tremendous morbidity. HPV vaccination is predicted to prevent HPV+ OP-SCC because over 90% are caused by vaccine-type HPV. However, current vaccination rates are not yet high enough to be effective at preventing HPV-associated malignancies at a population level. PMID:27132327

Fresh and mechanical properties of self-compacting concrete with coarse aggregate replacement using Waste of Oil Palm Shell

Science.gov (United States)

Prayuda, Hakas; Saleh, Fadillawaty; Ilham Maulana, Taufiq; Monika, Fanny

2018-05-01

Self-compacting Concrete (SCC) is a real innovation that can solidify itself without the help of tools to ease field practice. In its implementation, SCC can use alternative materials to reduce waste, such as Oil Palm Shell (OPS). In this research, OPS used as a replacement of crushed stone as the main coarse aggregate. The concrete mixture used consists of cement, sand, crushed stone, OPS as a variation of aggregate substitutes, palm oil fuel ash, and superplasticizer. OPS used were variated with 0%, 5%, 10%, 25% and 50% of crushed stone aggregate weight with age up to 28 days. Tests were conducted on fresh and mechanical properties. From the results, it is known that replacement of aggregate using OPS meets fresh properties criteria and although the compressive strength of OPS concrete mixture is lower than normal SCC, OPS still can be an alternative in making SCC and reducing palm oil industrial waste.

Small Radioisotope Power System Testing at NASA Glenn Research Center

Science.gov (United States)

Dugala, Gina; Bell, Mark; Oriti, Salvatore; Fraeman, Martin; Frankford, David; Duven, Dennis

2013-01-01

In April 2009, NASA Glenn Research Center (GRC) formed an integrated product team (IPT) to develop a Small Radioisotope Power System (SRPS) utilizing a single Advanced Stirling Convertor (ASC) with passive balancer. A single ASC produces approximately 80 We making this system advantageous for small distributed lunar science stations. The IPT consists of Sunpower, Inc., to provide the single ASC with a passive balancer, The Johns Hopkins University Applied Physics Laboratory (JHUAPL) to design an engineering model Single Convertor Controller (SCC) for an ASC with a passive balancer, and NASA GRC to provide technical support to these tasks and to develop a simulated lunar lander test stand. The single ASC with a passive balancer, simulated lunar lander test stand, and SCC were delivered to GRC and were tested as a system. The testing sequence at GRC included SCC fault tolerance, integration, electromagnetic interference (EMI), vibration, and extended operation testing. The SCC fault tolerance test characterized the SCCs ability to handle various fault conditions, including high or low bus power consumption, total open load or short circuit, and replacing a failed SCC card while the backup maintains control of the ASC. The integrated test characterized the behavior of the system across a range of operating conditions, including variations in cold-end temperature and piston amplitude, including the emitted vibration to both the sensors on the lunar lander and the lunar surface. The EMI test characterized the AC and DC magnetic and electric fields emitted by the SCC and single ASC. The vibration test confirms the SCCs ability to control the single ASC during launch. The extended operation test allows data to be collected over a period of thousands of hours to obtain long term performance data of the ASC with a passive balancer and the SCC. This paper will discuss the results of each of these tests.

Effects of nano-silica (NS) additions on durability of SCC mixtures

NARCIS (Netherlands)

Quercia Bianchi, G.; Spiesz, P.R.; Brouwers, H.J.H.; Andrade, C; Gulikers, JJW; Polder, R

2015-01-01

In this study, three different types of nano-silica were applied in self-compacting concrete (SCC), one produced by the controlled dissolution of the olivine mineral and two having similar particle size distributions (PSD), but produced through two different processes: fumed powder nano-silica and

Stress corrosion cracking

International Nuclear Information System (INIS)

Dietzel, W.; Turnbull, A.

2007-01-01

Comprehensive Structural Integrity is a reference work which covers all activities involved in the assurance of structural integrity. It provides engineers and scientists with an unparalleled depth of knowledge in the disciplines involved. The new online Volume 11 is dedicated to the mechanical characteristics of materials. This paper contains the chapter 11.03 and is structured as follows: General aspects of SCC testing; Non-precracked specimens; Precracked specimens - the fracture mechanics approach to SCC; Crack growth measurement; Limitations of the LEFM approach to SCC; The use of SCC data; Guide to selection of mechanical scc test method

SCC growth behavior of stainless steel weld metals in high-temperature water. Influence of corrosion potential, weld type, thermal aging, cold-work and temperature

International Nuclear Information System (INIS)

Yamada, Takuyo; Terachi, Takumi; Miyamoto, Tomoki; Arioka, Koji

2009-01-01

Recent studies on crack growth rate measurement in oxygenated high-temperature pure water conditions, such as normal water chemistry in boiling water reactors, using compact tension type specimens have shown that weld stainless steels are susceptible to stress corrosion cracking. However, to our knowledge, there is no crack growth data of weld stainless steels in pressurized water reactor primary water. The principal purpose of this study was to examine the SCC growth behavior of stainless steel weld metals in simulated PWR primary water. A second objective was to examine the effect of (1) corrosion potential, (2) thermal-aging, (3) Mo in alloy and (4) cold-working on SCC growth in hydrogenated and oxygenated water environments at 320degC. In addition, the temperature dependence of SCC growth in simulated PWR primary water was also studied. The results were as follows: (1) No significant SCC growth was observed on all types of stainless steel weld metals: as-welded, aged (400degC x 10 kh) 308L and 316L, in 2.7 ppm-hydrogenated (low-potential) water at 320degC. (2) 20% cold-working markedly accelerated the SCC growth of weld metals in high-potential water at 320degC, but no significant SCC growth was observed in the hydrogenated water, even after 20% cold-working. (3) No significant SCC growth was observed on stainless steel weld metals in low-potential water at 250degC and 340degC. Thus, stainless steel weld metals have excellent SCC resistance in PWR primary water. On the other hand, (4) significant SCC growth was observed on all types of stainless steel weld metals: as-weld, aged (400degC x 10 kh) and 20% cold-worked 308L and 316L, in 8 ppm-oxygenated (high-potential) water at 320degC. (5) No large difference in SCC growth was observed between 316L (Mo) and 308L. (6) No large effect on SCC growth was observed between before and after aging up to 400degC for 10 kh. (7) 20% cold-working markedly accelerated the SCC growth of stainless steel weld metals. (author)

Casticin impairs cell growth and induces cell apoptosis via cell cycle arrest in human oral cancer SCC-4 cells.

Science.gov (United States)

Chou, Guan-Ling; Peng, Shu-Fen; Liao, Ching-Lung; Ho, Heng-Chien; Lu, Kung-Wen; Lien, Jin-Cherng; Fan, Ming-Jen; La, Kuang-Chi; Chung, Jing-Gung

2018-02-01

Casticin, a polymethoxyflavone, present in natural plants, has been shown to have biological activities including anti-cancer activities. Herein, we investigated the anti-oral cancer activity of casticin on SCC-4 cells in vitro. Viable cells, cell cycle distribution, apoptotic cell death, reactive oxygen species (ROS) production, and Ca 2+ production, levels of ΔΨ m and caspase activity were measured by flow cytometric assay. Cell apoptosis associated protein expressions were examined by Western blotting and confocal laser microscopy. Results indicated that casticin induced cell morphological changes, DNA condensation and damage, decreased the total viable cells, induced G 2 /M phase arrest in SCC-4 cells. Casticin promoted ROS and Ca 2+ productions, decreases the levels of ΔΨ m , promoted caspase-3, -8, and -9 activities in SCC-4 cells. Western blotting assay demonstrated that casticin affect protein level associated with G2/M phase arrest and apoptosis. Confocal laser microscopy also confirmed that casticin increased the translocation of AIF and cytochrome c in SCC-4 cells. In conclusion, casticin decreased cell number through G 2 /M phase arrest and the induction of cell apoptosis through caspase- and mitochondria-dependent pathways in SCC-4 cells. © 2017 Wiley Periodicals, Inc.

Pre-radiotherapy and post-radiotherapy serial serum Squamous Cell Carcinoma antigen (SCC) and CarcinoEmbryonic Antigen (CEA) in the monitoring of squamous cell carcinoma of uterine cervix

Energy Technology Data Exchange (ETDEWEB)

Yun, Hyong Geun; Park, Choong Hak [College of Medicine, Dankook Univ., Chunan (Korea, Republic of)

1999-03-01

To evaluate the significance of squamous cell carcinoma antigen (SCC) and carcinoembryonic antigen (CEA) as tumor markers in uterine cervix carcinoma. In 22 patients with histologically proven primary squamous cell carcinoma of uterine cervix, tumor volume was checked either by using MRI (in 20 patients) or ultrasound (in 2 patients). Pre-treatment serum SCC levels were checked in 22 patients and CEA levels in 21 patients. After curative radiotherapy, post-treatment SCC and CEA were checked regularly. SCC was raised in 68.2% and CEA was raised in 19.0% before treatment. The coefficient of correlation between tumor volume and pre-reatment SCC was 0.59382 when one extremely deviated case was excluded. And there was no correlation between tumor volume and CEA. After the treatment, SCC was raised in 9.1% and CEA was raised in 4.8%. In further follow up measurement, raise of SCC was associated with clinical relapse or persistence of disease. The specificity of raised SCC level in association with recurrent or persistent disease was 93.8%. The sensitivity in association with recurrent or persistent disease was 100%. The positive predictive values was 85.7%. The median lead time for recurrence was 1.2 months. Both SCC and CEA were good tumor markers for monitoring treatment effect in patients with raised pre-treatment levels. But the sensitivity of pretreatment CEA was low, while that of pretreatment SCC was high. And there was no additional gain by adding CEA measurements to SCC measurements.

Pre-radiotherapy and post-radiotherapy serial serum Squamous Cell Carcinoma antigen (SCC) and CarcinoEmbryonic Antigen (CEA) in the monitoring of squamous cell carcinoma of uterine cervix

International Nuclear Information System (INIS)

Yun, Hyong Geun; Park, Choong Hak

1999-01-01

To evaluate the significance of squamous cell carcinoma antigen (SCC) and carcinoembryonic antigen (CEA) as tumor markers in uterine cervix carcinoma. In 22 patients with histologically proven primary squamous cell carcinoma of uterine cervix, tumor volume was checked either by using MRI (in 20 patients) or ultrasound (in 2 patients). Pre-treatment serum SCC levels were checked in 22 patients and CEA levels in 21 patients. After curative radiotherapy, post-treatment SCC and CEA were checked regularly. SCC was raised in 68.2% and CEA was raised in 19.0% before treatment. The coefficient of correlation between tumor volume and pre-reatment SCC was 0.59382 when one extremely deviated case was excluded. And there was no correlation between tumor volume and CEA. After the treatment, SCC was raised in 9.1% and CEA was raised in 4.8%. In further follow up measurement, raise of SCC was associated with clinical relapse or persistence of disease. The specificity of raised SCC level in association with recurrent or persistent disease was 93.8%. The sensitivity in association with recurrent or persistent disease was 100%. The positive predictive values was 85.7%. The median lead time for recurrence was 1.2 months. Both SCC and CEA were good tumor markers for monitoring treatment effect in patients with raised pre-treatment levels. But the sensitivity of pretreatment CEA was low, while that of pretreatment SCC was high. And there was no additional gain by adding CEA measurements to SCC measurements

SCC500: next-generation infrared imaging camera core products with highly flexible architecture for unique camera designs

Science.gov (United States)

Rumbaugh, Roy N.; Grealish, Kevin; Kacir, Tom; Arsenault, Barry; Murphy, Robert H.; Miller, Scott

2003-09-01

A new 4th generation MicroIR architecture is introduced as the latest in the highly successful Standard Camera Core (SCC) series by BAE SYSTEMS to offer an infrared imaging engine with greatly reduced size, weight, power, and cost. The advanced SCC500 architecture provides great flexibility in configuration to include multiple resolutions, an industry standard Real Time Operating System (RTOS) for customer specific software application plug-ins, and a highly modular construction for unique physical and interface options. These microbolometer based camera cores offer outstanding and reliable performance over an extended operating temperature range to meet the demanding requirements of real-world environments. A highly integrated lens and shutter is included in the new SCC500 product enabling easy, drop-in camera designs for quick time-to-market product introductions.

Latest SCC Issues of core shroud and recirculation piping in Japanese BWRs

International Nuclear Information System (INIS)

Okamura, Yuichi; Sakashita, Akihiro; Fukuda, Toshihiko; Yamashita, Hironobu; Futami, Tsuneo

2003-01-01

This paper reports that a high incidence of stress corrosion cracking (SCC) cracks have been found in the core Shroud and PLR piping of several Japanese BWR plants. The results of investigations show the cracks to be of SCC type in 316L stainless steel and with different characteristics from the type in 304 stainless steel. The cracks on the shroud surface were mainly verified near the shroud ring weld line and core region weld line, and the crack shape could be classified into two types: one type was circumferential cracking in the shroud ring, and the other was isolated occurrences of radial cracking in the core region. The structural integrity of those shrouds with cracks was evaluated under a conservative assumption and confirmed to be adequate. A relatively large error was identified in measuring the crack depth in the PLR piping. (author)

PCI/SCC failure behavior of KWU/CE fuel rods

International Nuclear Information System (INIS)

Kikuchi, Akira

1983-10-01

The Over Ramp (Studsvik Over Ramp-STOR) project is an international power ramping irradiation program for studying PCI/SCC failure behavior of PWR-fuel rods. The project had its activities for about three years (Apr., 1977 - Dec., 1980) as the cooperation works of twelve participants composing nine countries. The present report introduces the irradiation data on the KWU/CE fuel rods in the project and discusses the failure behavior of PWR-fuel rods. (author)

LAFD: TA-3 NISC & SCC Facility Familiarization Tour, OJT #53356

Energy Technology Data Exchange (ETDEWEB)

Rutherford, Victor Stephen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Norman, Rich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Montoya, Gene [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Blumberg, Paul A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); McCurdy, Patrick B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-10-24

Los Alamos National Laboratory (LANL, the Laboratory, or the Lab) conducts familiarization tours for Los Alamos County Fire Department (LAFD) personnel at the Strategic Computing Complex (SCC), TA-03-2327, and the Nonproliferation & International Security Complex (NISC), TA-03-2322. These tours are official LANL business; their purpose is to orient the firefighters to the SCC and the NISC so that they can respond efficiently and quickly to a variety of emergency situations. The tour includes ingress and egress of the buildings, layout and organization of the buildings, evacuation procedures, and areas of concern to emergency responders within these buildings. LAFD firefighters have the training, skills, and abilities to perform these emergency responder tasks; other LANL personnel who have the required clearance level cannot perform these tasks. This handout provides details of the information, along with maps and diagrams, to be presented during the familiarization tours. The report will be distributed to the trainees at the time of the tour. A corresponding checklist will also be used as guidance during the familiarization tours to ensure that all required information is presented to the LAFD personnel.

Mechanical Performance Evaluation of Self-Compacting Concrete with Fine and Coarse Recycled Aggregates from the Precast Industry.

Science.gov (United States)

Santos, Sara A; da Silva, Pedro R; de Brito, Jorge

2017-08-04

This paper intends to evaluate the feasibility of reintroducing recycled concrete aggregates in the precast industry. The mechanical properties of self-compacting concrete (SCC) with incorporation of recycled aggregates (RA) (coarse recycled aggregates (CRA) and fine recycled aggregates (FRA)) from crushed precast elements were evaluated. The goal was to evaluate the ability of producing SCC with a minimum pre-established performance in terms of mechanical strength, incorporating variable ratios of RA (FRA/CRA%: 0/0%, 25/25%, 50/50%, 0/100% and 100/0%) produced from precast source concretes with similar target performances. This replication in SCC was made for two strength classes (45 MPa and 65 MPa), with the intention of obtaining as final result concrete with recycled aggregates whose characteristics are compatible with those of a SCC with natural aggregates in terms of workability and mechanical strength. The results enabled conclusions to be established regarding the SCC's produced with fine and coarse recycled aggregates from the precast industry, based on its mechanical properties. The properties studied are strongly affected by the type and content of recycled aggregates. The potential demonstrated, mainly in the hardened state, by the joint use of fine and coarse recycled aggregate is emphasized.

SCC growth behaviors of austenitic stainless steels in simulated PWR primary water

Science.gov (United States)

Terachi, T.; Yamada, T.; Miyamoto, T.; Arioka, K.

2012-07-01

The rates of SCC growth were measured under simulated PWR primary water conditions (500 ppm B + 2 ppm Li + 30 cm3/kg-H2O-STP DH2) using cold worked 316SS and 304SS. The direct current potential drop method was applied to measure the crack growth rates for 53 specimens. Dependence of the major engineering factors, such as yield strength, temperature and stress intensity was systematically examined. The rates of crack growth were proportional to the 2.9 power of yield strength, and directly proportional to the apparent yield strength. The estimated apparent activation energy was 84 kJ/mol. No significant differences in the SCC growth rates and behaviors were identified between 316SS and 304SS. Based on the measured results, an empirical equation for crack growth rate was proposed for engineering applications. Although there were deviations, 92.8% of the measured crack growth rates did not exceed twice the value calculated by the empirical equation.

Clinical diagnostic significance of combined detection of serum and pleural effusion levels of CEA, NSE, CYFRA21-1, SCC-Ag in patients with lung cancer

International Nuclear Information System (INIS)

Bian Baoxiang; Hu Nan; Wu Fenglei; Yang Chengxi

2008-01-01

Objective: To appraise the clinical diagnostic significance of combined detection of serum and chest fluid levels of CEA, NSE, CYFRA21-1 and SCC-Ag in patients with lung cancer. Methods: Serum and pleural effusion contents of CEA, NSE, CYFRA21-1 and SCC-Ag were determined with RIA in 54 patients with lung cancer and 35 patients with benign lung disorders. Results: The serum and pleural effusion contents of CEA, NSE, CYFRA21-1 and SCC-Ag in patients with lung cancer were significantly higher than those in patients with benign lung disorders (P<0.01). The contents of CEA, NSE, CYFRA21-1 and SCC-Ag in patients pleural effusion were significantly higher than those in patients serum (P<0.01). For combined detection of CEA, NSE, CYFRA21-1 and SCC-Ag in serum and pleural effusion, the positive rate was 83.33% and 92.59% respectively. Conclusion: Combined detection of CEA, NSE, CYFRA21-1 and SCC-Ag contents in serum and pleural effusion can increase the positive rate of lung cancer diagnosis. (authors)

Fisetin-induced apoptosis of human oral cancer SCC-4 cells through reactive oxygen species production, endoplasmic reticulum stress, caspase-, and mitochondria-dependent signaling pathways.

Science.gov (United States)

Su, Chen-Hsuan; Kuo, Chao-Lin; Lu, Kung-Wen; Yu, Fu-Shun; Ma, Yi-Shih; Yang, Jiun-Long; Chu, Yung-Lin; Chueh, Fu-Shin; Liu, Kuo-Ching; Chung, Jing-Gung

2017-06-01

Oral cancer is one of the cancer-related diseases in human populations and its incidence rates are rising worldwide. Fisetin, a flavonoid from natural products, has been shown to exhibit anticancer activities in many human cancer cell lines but the molecular mechanism of fisetin-induced apoptosis in human oral cancer cells is still unclear; thus, in this study, we investigated fisetin-induced cell death and associated signal pathways on human oral cancer SCC-4 cells in vitro. We examined cell morphological changes, total viable cells, and cell cycle distribution by phase contrast microscopy and flow cytometry assays. Reactive oxygen species (ROS), Ca 2+ , mitochondria membrane potential (ΔΨ m ), and caspase-8, -9, and -3 activities were also measured by flow cytometer. Results indicate that fisetin induced cell death through the cell morphological changes, caused G2/M phase arrest, induction of apoptosis, promoted ROS and Ca 2+ production, and decreased the level of ΔΨ m and increased caspase-3, -8, and -9 activities in SCC-4 cells. DAPI staining and DNA gel electrophoresis were also used to confirm fisetin-induced cell apoptosis in SCC-4 cells. Western blotting also found out that Fisetin increased the proapoptotic proteins such as Bax and Bid and decreased the antiapoptotic proteins such as Bcl-2. Furthermore, results also showed that Fisetin increased the cytochrome c, AIF, and Endo G release from mitochondria in SCC-4 cells. We also used ATF-6α, ATF-6β, GADD153, and GRP78 which indicated that fisetin induced cell death through ER stress. Based on those observations, we suggest that fisetin induced cell apoptosis through ER stress, mitochondria-, and caspase-dependent pathways. © 2017 Wiley Periodicals, Inc.

Critical study of test methods in stress corrosion cracking. Application to stainless steels in chloride environment

International Nuclear Information System (INIS)

Ajana, Lotfi

1985-01-01

The transposition of results obtained in laboratory to the prediction of in-service material resistance is a crucial problem in the case of stress corrosion cracking (SCC). The search for a SCC test which allows a reliable and realistic classification of stainless steels in chloride environments requires a choice of adequate electrolytes and of mechanical solicitation mode. In this research, the author first justifies the choice of an environment which could be representative of actual service conditions in the case of 5 grades of austenitic steels and 1 grade of austeno-ferric steel. Using a computerized data acquisition and processing system, the author compares the information obtained with two types of test: under constant load and under slow strain rate [fr

SCC behavior of alloy 690 from a CDRM mock-up

International Nuclear Information System (INIS)

Lapena, J.; Sol Garcia-Redondo, M. del; Perosanz, F.J.; Saez, A.; Gomez-Briceno, D.; Castelao, C.

2015-01-01

Stress corrosion cracking (SCC) response of Alloy 690 when the material has been subjected to nonuniform cold working is of interest to understand the behavior of the weld heat affected zone (HAZ) of Alloy 690 in which localised plastic strain exists due to weld shrinkage. This has a special interest in the case of control-rod-drive mechanisms (CRDM) of vessel head. To simulate these conditions during last years many crack growth rate (CGR) data were obtained in deformed material by cold work (rolling, forging or tensile straining), up to 40% of cold working. However, it is unclear to what extent this simulation procedure reproduces the conditions of the material in a CRDM. A research project is being carried out in order to obtain CGR data in realistic situations existing in operating power plants, by the use of CT specimens extracted from CRDMs. This presentation shows the characterization and some results of crack growth rate data on Alloy 690 TT base metal/HAZ/weld metal using specimens made from a CRDM mock-up. It has been fabricated following the usual procedures used for the RPV head fabrication for the Spanish PWR NPP. (authors)

Stress corrosion mechanisms of alloy-600 polycrystals and monocrystals in primary water: effect of hydrogen

International Nuclear Information System (INIS)

Foct, F.

1999-01-01

The aim of this study is to identify the mechanisms involved in Alloy 600 primary water stress corrosion cracking. Therefore, this work is mainly focussed on the two following points. The first one is to understand the influence of hydrogen on SCC of industrial Alloy 600 and the second one is to study the crack initiation and propagation on polycrystals and single crystals. A cathodic potential applied during slow strain rate tests does not affect crack initiation but increases the slow crack growth rate by a factor 2 to 5. Cathodic polarisation, cold work and 25 cm 3 STP/kg hydrogen content increase the slow CGR so that the K ISCC (and therefore fast CGR) is reached. The influence of hydrogenated primary water has been studied for the first time on Alloy 600 single crystals. Cracks cannot initiate on tensile specimens but they can propagate on pre-cracked specimens. Transgranular cracks present a precise crystallographic aspect which is similar to that of 316 alloy in MgCl 2 solutions. Moreover, the following results improve the description of the cracking conditions. Firstly, the higher the hydrogen partial pressure, the lower the Alloy 600 passivation current transients. Since this result is not correlated with the effect of hydrogen on SCC, cracking is not caused by a direct effect of dissolved hydrogen on dissolution. Secondly, hydrogen embrittlement of Alloy 600 disappears at temperatures above 200 deg.C. Thirdly, grain boundary sliding (GBS) does not directly act on SCC but shows the mechanical weakness of grain boundaries. Regarding the proposed models for Alloy 600 SCC, it is possible to draw the following conclusions. Internal oxidation or absorbed hydrogen effects are the most probable mechanisms for initiation. Dissolution, internal oxidation and global hydrogen embrittlement models cannot explain crack propagation. On the other hand, the Corrosion Enhanced Plasticity Model gives a good description of the SCC propagation. (author)

SCC propagation and cessation behavior near the fusion boundary of dissimilar weld joint with Ni-based weld metal and low alloy steel

International Nuclear Information System (INIS)

Ishizawa, Makoto; Abe, Hiroshi; Watanabe, Yutaka

2009-01-01

The purpose of this study is to investigate the following items focused on the microstructure near the fusion boundary of dissimilar weld joint with Ni-based weld metal and low alloy steel; (1) Microstructural characteristics near the fusion boundary, (2) Dominant factor that makes crack retardation near the fusion boundary. Main conclusions can be summarized as follows; (1) From the results of CBB tests, it has been understood that the low alloy steel has no SCC susceptibility and that there is a difference in oxidation behavior between high and low sulfur containing low alloy steel, (2) In Alloy182/LAS sample, most of crack tips were located at the fusion boundary. It has been thought that crack become less active when crack reach at fusion boundary, (3) It has been suggested that the dominant factor of crack retardation is low SCC susceptibility of low alloy steel in high temperature water. (author)

Evaluation of neutron irradiation effect on SCC crack growth behaviour of austenitic stainless steel

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-08-15

Austenitic stainless steels are widely used as structural materials alloy in reactor pressure vessel internal components because of their high strength, ductility and fracture toughness. However, exposure due to neutron irradiation results in changes in microstructure, mechanical properties and microchemistry of the material. Irradiation assisted stress corrosion cracking (IASCC) caused by the effect of neutron irradiation during long term operation in high temperature water environments in nuclear power plants is considered to take the form of intergranular stress corrosion cracking (IGSCC) and the critical fluence level has been reported to be about 5x10{sup 24}n/m{sup 2} (E>1MeV) for Type 304 SS in BWR environment. JNES had been conducting IASCC project during from JFY 2000 to JFY 2008, and prepared an engineering database on IASCC. However, the data of crack growth rate (CGR) below the critical fluence level are not sufficient. Therefore, evaluation of neutron irradiation effect project (ENI) was initiated to obtain the CGR data below the critical fluence level, and prepare the SCC growth rate diagram for life time evaluation of core shroud. Test specimens have been irradiated in the OECD/Halden reactor, and the post irradiation experiments (PIE) have been conducting during from JFY 2011 to JFY 2013, finally the modified IASCC guide will be prepared in JFY 2013. (author)

Monitoring Conditions Leading to SCC/Corrosion of Carbon Steel in Fuel Grade Ethanol

Science.gov (United States)

2011-02-11

This is the draft final report of the project on field monitoring of conditions that lead to SCC in ethanol tanks and piping. The other two aspects of the consolidated program, ethanol batching and blending effects (WP#325) and source effects (WP#323...

Analysis of the truth loading conditions of a austenitic CT specimen during a SCC experiment

International Nuclear Information System (INIS)

Marie, S.; Guerre, C.; Herms, E.

2012-01-01

samples have been machined/prepared, the residual stresses field in the specimen after its machining is calculated and then taken into account in the mechanical analysis. The characteristics of this field in addition to the mechanical loading applied during SCC testing can explain the crack propagation behavior observed experimentally. (authors)

Mechanical Testing of MLCCs

Science.gov (United States)

Teverovsky, Alexander A.

2016-01-01

Cracking of multilayer ceramic capacitors, MLCCs, remains a serious problem for space systems. This problem increases substantially for large size capacitors and in cases when manual soldering is involved or the system experiences mechanical shock or vibration. In any case, a fracture occurs when the sum of external and internal mechanical stresses exceeds the strength of the part. To reduce the probability of cracking, the level of stress should be reduced, e.g. by optimizing the assembly workmanship and rules for board design, and the strength of the parts increased by selecting the most mechanically robust capacitors. The latter might possibly be achieved by selecting MLCCs based on the in-situ measurements of mechanical characteristics using four types of tests: flexural strength, hardness, fracture toughness, and flex bend testing. Note that military specifications MIL-PRF-123 and MIL-PRF-55681 do not have requirements for mechanical testing of the parts. However, specifications for automotive industry components employ two types of mechanical tests: beam load (break strength) test per AEC-Q200-003 and board flex test per AEC-Q200-005. A recent military specification for thin dielectric capacitors, MIL-PRF-32535, has one mechanical test, board flex testing, that is similar to AEC-Q200-005. The purpose of this report was assessment of the efficiency of different mechanical tests for selection robust capacitors and comparison of mechanical characteristics of Base Metal Electrode (BME) and Precious Metal Electrode (PME) capacitors. The report has three parts related to the first three mechanical tests mentioned above.

Effect of corrosion product layer on SCC susceptibility of copper containing type 304 stainless steel in 1 M H2SO4

International Nuclear Information System (INIS)

Asawa, M.; Devasenapathi, A.; Fujisawa, M.

2004-01-01

The effect of surface corrosion product layer on the stress corrosion cracking (SCC) susceptibility of type 304 stainless steel with Cu was studied in 1 kmol/m 3 (1 M) sulfuric acid at 353 K temperature. Studies based on the intermittent removal of surface corrosion product layer indicated that the surface film governs the SCC behavior of the alloy by accelerating both the crack initiation and propagation stages. The electrochemical impedance and polarization studies showed the surface layer to be promoting SCC initiation by lowering the uniform corrosion rate and the propagation by shifting the surface corrosion potential to a more noble direction. The elemental analysis of the corrosion product both by the energy dispersive X-ray (EDX) spectroscopy and by X-ray diffraction (XRD) analysis along with the thermodynamic calculations showed the layer to be constituted mainly of metallic copper (Cu) and the mono-hydrated iron sulfate which acts as cathode promoting SCC

Subclinical mastitis in dairy camels in Algeria: Comparison of screening tests

Directory of Open Access Journals (Sweden)

Leyla HADEF

2017-02-01

Full Text Available The aim of the present study was to determine a threshold values and to assess the effectiveness of four indirect tests for the diagnosis of subclinical mastitis in dairy camels comparing with bacteriological culture. One hundred fifty three milk samples from 17 lactating camels were subjected to bacteriological culture, where 84 milk samples were positive, 47 were negative and 22 samples were considered as contaminated. A total of 131 milk samples were screened by pH, electrical conductivity (EC, California mastitis test (CMT and somatic cell count (SCC. The good combination of sensitivity and specificity were obtained with a threshold of 6.55, 7.2 mS/cm, score trace was considered as CMT (+ and 240 000 cells/ml for the four tests, respectively. The sensitivity of the SCC, pH, EC and CMT was 72.61, 66.66, 47.61 and 39.28 %; the specificity 70.21, 38.02, 59.57 and 72.34 %; percentage accuracy 71.75, 51.14, 51.90 and 51.14 %; and positive predictive value 81.33, 47.61, 67.79 and 71.73 %, respectively. The SCC was significantly correlated with bacteriological culture (r = 0.415, p < 0.05. Kappa value of SCC was higher than that of other tests (SCC > CMT > EC > pH. In conclusion, the results suggest that the SCC was the most accurate, reliable, diagnostic method compared to other tests used in this study after cultural isolation for the detection of subclinical mastitis in dairy camel under field conditions.

Stress corrosion crack initiation of Zircaloy-4 cladding tubes in an iodine vapor environment during creep, relaxation, and constant strain rate tests

Science.gov (United States)

Jezequel, T.; Auzoux, Q.; Le Boulch, D.; Bono, M.; Andrieu, E.; Blanc, C.; Chabretou, V.; Mozzani, N.; Rautenberg, M.

2018-02-01

During accidental power transient conditions with Pellet Cladding Interaction (PCI), the synergistic effect of the stress and strain imposed on the cladding by thermal expansion of the fuel, and corrosion by iodine released as a fission product, may lead to cladding failure by Stress Corrosion Cracking (SCC). In this study, internal pressure tests were conducted on unirradiated cold-worked stress-relieved Zircaloy-4 cladding tubes in an iodine vapor environment. The goal was to investigate the influence of loading type (constant pressure tests, constant circumferential strain rate tests, or constant circumferential strain tests) and test temperature (320, 350, or 380 °C) on iodine-induced stress corrosion cracking (I-SCC). The experimental results obtained with different loading types were consistent with each other. The apparent threshold hoop stress for I-SCC was found to be independent of the test temperature. SEM micrographs of the tested samples showed many pits distributed over the inner surface, which tended to coalesce into large pits in which a microcrack could initiate. A model for the time-to-failure of a cladding tube was developed using finite element simulations of the viscoplastic mechanical behavior of the material and a modified Kachanov's damage growth model. The times-to-failure predicted by this model are consistent with the experimental data.

Value and significance of tumor markers as CEA, CA125, SCC-Ag, CA199 and CYFRA21-1 in the diagnosis of cervical cancer

Directory of Open Access Journals (Sweden)

Xiao-Juan Wang

2017-09-01

Full Text Available Objective: To investigate the value and significance of serum CEA, CA125, SCC-Ag, CA199 and CYFRA21-1 in the diagnosis of cervical cancer by comparing the detection of five serum markers. Methods: A total of 108 cases were divided into three groups, including 60 cervical cancerpatients and 20 cervical intraepithelial neoplasiain patients treated in our hospital from September 2015 to September 2016 and 28 healthy women. Radioimmunoassay was used to detect and compare the serum levels of CA125, CA199, CYFRA21-1 and ELISA method was used to detect and compare the serum levels of SCC-Ag, CEA. Results: (1 There was no statistically significant difference in the serum CEA, CA125, SCC-Ag, CA199, CYFRA21-1 levels between CIN group and control group. The serums CEA, CA125, SCC-Ag, CA199, CYFRA21-1 levels of cervical cancer patients were significantly higher than the other two groups. The differences were statistically significant. (2There were statistically significant differences in the serum CEA, CA125, SCC-Ag, CA199, CYFRA21-1 levels between different cervical pathological type groups.The serum CA125, CA199, CEA levels of cervical glandular cancer patients were significantly higher than the other two groups. The differences were statistically significant. The serum SCC-Ag, CYFRA21-1 levels of cervical squamous cancer patients were significantly higher than the other two groups. The differences were statistically significant. Conclusion: The serums CEA, CA125, SCC-Ag, CA199, CYFRA21-1 levels of cervical cancer patients were significantly higher than cervical intraepithelial neoplasiain patients and healthy women. The serum CA125, CA199, CEA levels of cervical glandular cancer patients were significantly higher and the serum SCC-Ag, CYFRA21-1 levels of cervical squamous cancer patients were significantly higher. The five tumor markers can be used in diagnosis of cervical cancer and they are also worthy in distinguishing cervical pathological types.

A study of long-term static load on degradation and mechanical integrity of Mg alloys-based biodegradable metals

International Nuclear Information System (INIS)

Koo, Youngmi; Jang, Yongseok; Yun, Yeoheung

2017-01-01

Highlights: • Long-term stress corrosion cracking (SCC) test of Mg alloys was performed. • AZ31B-H24 shows transgranular stress corrosion cracking (TGSCC) and ZE41A-T5 intergranular stress corrosion cracking (IGSCC). • Long-term static loading accelerated crack propagation, leading to the loss of mechanical strength. - Abstract: Predicting degradation behavior of biodegradable metals in vivo is crucial for the clinical success of medical devices. This paper reports on the effect of long-term static stress on degradation of magnesium alloys and further changes in mechanical integrity. AZ31B (H24) and ZE41A (T5) alloys were tested to evaluate stress corrosion cracking (SCC) in a physiological solution for 30 days and 90 days (ASTM G39 testing standard). Scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) and micro-computed tomography (micro-CT) were used to characterize surface morphology and micro-structure of degraded alloys. The results show the different mechanisms of stress corrosion cracking for AZ31B (transgranular stress corrosion cracking, TGSCC) and ZE41A (intergranular stress corrosion cracking, IGSCC). AZ31B was more susceptible to stress corrosion cracking under a long term static load than ZE41A. In conclusion, we observed that long-term static loading accelerated crack propagation, leading to the loss of mechanical integrity.

A study of long-term static load on degradation and mechanical integrity of Mg alloys-based biodegradable metals

Energy Technology Data Exchange (ETDEWEB)

Koo, Youngmi; Jang, Yongseok; Yun, Yeoheung, E-mail: yyun@ncat.edu

2017-05-15

Highlights: • Long-term stress corrosion cracking (SCC) test of Mg alloys was performed. • AZ31B-H24 shows transgranular stress corrosion cracking (TGSCC) and ZE41A-T5 intergranular stress corrosion cracking (IGSCC). • Long-term static loading accelerated crack propagation, leading to the loss of mechanical strength. - Abstract: Predicting degradation behavior of biodegradable metals in vivo is crucial for the clinical success of medical devices. This paper reports on the effect of long-term static stress on degradation of magnesium alloys and further changes in mechanical integrity. AZ31B (H24) and ZE41A (T5) alloys were tested to evaluate stress corrosion cracking (SCC) in a physiological solution for 30 days and 90 days (ASTM G39 testing standard). Scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) and micro-computed tomography (micro-CT) were used to characterize surface morphology and micro-structure of degraded alloys. The results show the different mechanisms of stress corrosion cracking for AZ31B (transgranular stress corrosion cracking, TGSCC) and ZE41A (intergranular stress corrosion cracking, IGSCC). AZ31B was more susceptible to stress corrosion cracking under a long term static load than ZE41A. In conclusion, we observed that long-term static loading accelerated crack propagation, leading to the loss of mechanical integrity.

Self-compacting concrete containing different powders at elevated temperatures - Mechanical properties and changes in the phase composition of the paste

International Nuclear Information System (INIS)

Bakhtiyari, S.; Allahverdi, A.; Rais-Ghasemi, M.; Zarrabi, B.A.; Parhizkar, T.

2011-01-01

Fire resistance of self-compacting concretes (SCC) containing limestone and quartz powders, with two different compressive strengths, were evaluated and compared with normal concretes (NC). The residual mechanical strengths of the mixes at different temperatures were measured. The changes in the phase composition of the cement pastes at high temperatures were examined with thermal analysis and X-ray diffractometry methods. The SCC mixes showed a higher susceptibility to spalling at high temperatures but the NC mixes suffered much more from loss of the mechanical strengths. Both the powder types and the compressive strength notably influenced the fire behavior of the SCC. The quartz powder accelerated the hydration of the SCC cement paste at high temperatures, up to 500 o C. However, the quartz-contained SCC showed the highest risk of spalling among all the mixes. The results showed that the thermal analysis could be a useful device for evaluating the fire behavior of building materials.

Self-compacting concrete containing different powders at elevated temperatures - Mechanical properties and changes in the phase composition of the paste

Energy Technology Data Exchange (ETDEWEB)

Bakhtiyari, S., E-mail: bakhtiyari@bhrc.ac.ir [School of Chemical Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Allahverdi, A., E-mail: ali.allahverdi@iust.ac.ir [Cement Research Center, School of Chemical Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114 (Iran, Islamic Republic of); Rais-Ghasemi, M., E-mail: raissghasemi@bhrc.ac.ir [Dep. of Concrete Technology, Building and Housing Research Center (BHRC), Tehran (Iran, Islamic Republic of); Zarrabi, B.A., E-mail: zarrabi@chalmers.se [Fire Technology Dep., SP Technical Research Institute of Sweden (Sweden); Parhizkar, T., E-mail: parhizkar@bhrc.ac.ir [Dep. of Concrete Technology, Building and Housing Research Center (BHRC), Tehran (Iran, Islamic Republic of)

2011-02-20

Fire resistance of self-compacting concretes (SCC) containing limestone and quartz powders, with two different compressive strengths, were evaluated and compared with normal concretes (NC). The residual mechanical strengths of the mixes at different temperatures were measured. The changes in the phase composition of the cement pastes at high temperatures were examined with thermal analysis and X-ray diffractometry methods. The SCC mixes showed a higher susceptibility to spalling at high temperatures but the NC mixes suffered much more from loss of the mechanical strengths. Both the powder types and the compressive strength notably influenced the fire behavior of the SCC. The quartz powder accelerated the hydration of the SCC cement paste at high temperatures, up to 500 {sup o}C. However, the quartz-contained SCC showed the highest risk of spalling among all the mixes. The results showed that the thermal analysis could be a useful device for evaluating the fire behavior of building materials.

A study on the mechanism of stress corrosion cracking of duplex stainless steels in hot alkaline-sulfide solution

Science.gov (United States)

Chasse, Kevin Robert

Duplex stainless steels (DSS) generally have superior strength and corrosion resistance as compared to most standard austenitic and ferritic stainless grades owing to a balanced microstructure of austenite and ferrite. As a result of having favorable properties, DSS have been selected for the construction of equipment in pulp and paper, chemical processing, nuclear, oil and gas as well as other industries. The use of DSS has been restricted in some cases because of stress corrosion cracking (SCC), which can initiate and grow in either the ferrite or austenite phase depending on the environment. Thorough understanding of SCC mechanisms of DSS in chloride- and hydrogen sulfide-containing solutions has been useful for material selection in many environments. However, understanding of SCC mechanisms of DSS in sulfide-containing caustic solutions is limited, which has restricted the capacity to optimize process and equipment design in pulp and paper environments. Process environments may contain different concentrations of hydroxide, sulfide, and chloride, altering corrosion and SCC susceptibility of each phase. Crack initiation and growth behavior will also change depending on the relative phase distribution and properties of austenite and ferrite. The role of microstructure and environment on the SCC of standard grade UNS S32205 and lean grade UNS S32101 in hot alkaline-sulfide solution were evaluated in this work using electrochemical, film characterization, mechanical testing, X-ray diffraction, and microscopy techniques. Microstructural aspects, which included residual stress state, phase distribution, phase ratio, and microhardness, were related to the propensity for SCC crack initiation in different simulated alkaline pulping liquors at 170 °C. Other grades of DSS and reference austenitic and superferritic grades of stainless steel were studied using exposure coupons for comparison to understand compositional effects and individual phase susceptibility

2,2′,4,4′-Tetrabromodiphenyl ether (BDE-47) decreases progesterone synthesis through cAMP-PKA pathway and P450scc downregulation in mouse Leydig tumor cells

International Nuclear Information System (INIS)

Han, Xiumei; Tang, Rong; Chen, Xiaojiao; Xu, Bo; Qin, Yufeng; Wu, Wei; Hu, Yanhui; Xu, Bin; Song, Ling; Xia, Yankai; Wang, Xinru

2012-01-01

Polybrominated diphenyl ethers (PBDEs) are commonly used as flame retardants in textiles, plastics and electronics and represent a group of persistent environmental contaminants. They have been found to accumulate in human and marine mammals. Previous studies have shown that PBDEs have endocrine-disrupting properties and reproductive toxicity. However, the mechanisms under the reproductive disruptions are still not well understood. In this study, we explored the effects of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) on progesterone biosynthesis and possible mechanisms in mouse Leydig tumor cells (mLTC-1). Our results showed that BDE-47 could reduce progesterone production and decrease the intracellular cAMP level induced by hCG or forskolin. These suggested that BDE-47 decreasing progesterone production in mLTC-1 cells may be associated with the decline of intracellular cAMP level. Moreover, our data also indicated that the site G protein in cAMP-PKA pathway may be involved in this process. Furthermore, the addition of cAMP analog, 8-Br-cAMP, could not reverse the decrease of progesterone biosynthesis, indicating that a post-cAMP site (or sites) might be involved into the BDE-47-decreased progesterone production. In addition, we found BDE-47 reduced the activity of P450 side chain cleavage enzyme (P450scc), which was companied with the decline of P450scc mRNA and protein level in mLTC-1 cells. Put all together, these results suggested that progesterone synthesis decrease induced by BDE-47 may be associated with attenuation of cAMP generation and reduction of P450scc activity.

Calibration Device Designed for proof ring used in SCC Experiment

Science.gov (United States)

Hu, X. Y.; Kang, Z. Y.; Yu, Y. L.

2017-11-01

In this paper, a calibration device for proof ring used in SCC (Stress Corrosion Cracking) experiment was designed. A compact size loading device was developed to replace traditional force standard machine or a long screw nut. The deformation of the proof ring was measured by a CCD (Charge-Coupled Device) during the calibration instead of digital caliper or a dial gauge. The calibration device was verified at laboratory that the precision of force loading is ±0.1% and the precision of deformation measurement is ±0.002mm.

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.

Vibrational absorption spectra, DFT and SCC-DFTB conformational study and analysis of [Leu]enkephalin

DEFF Research Database (Denmark)

Abdali, Salim; Niehaus, T.A.; Jalkanen, Karl J.

2003-01-01

. Ab initio (DFT at the B3LYP/6-31G* level of theory) and semi-empirical (SCC-DFTB) with and without dispersion correction were applied to simulate the VA spectra of [Leu] enkephalin. In these calculations structures taken from X-ray measurements for different conformers of the molecule were used...

General aspects of the mechanical integrity of canisters

International Nuclear Information System (INIS)

Saario, Timo

2007-01-01

This paper attempts to introduce a new point of view to the mechanical integrity of the canisters, 'mechanical integrity evolutionary path'. The mechanical integrity evolutionary path is a description of development of the critical parameters involved in the prevailing degradation modes as a function of time. The degradation mechanisms considered are: mechanical overload; creep; and stress corrosion cracking. For each degradation mechanism one may consider two different states; initial state; critical state. The initial state considered will be different for different degradation mechanisms. For example stress corrosion cracking (SCC), which involves electrochemical steps is not possible without a surface covering aqueous phase. Thus, potentially, the initial state for SCC is that existing after saturation. On the other hand, the initial state for a possible mechanical overload can be different in different periods during the mechanical integrity evolutionary path. During the handling and transport stages the initial state is 'ex works', while during a glaciation the initial state has been altered due to creep, corrosion and possible SCC processes. The canister will go through mechanical overload during saturation and bentonite swelling phases and it will deform to fit the form of the insert. The initial state for this period is 'ex works', with e.g. manufacturing defects. The insert is designed to bear the load after closing the gap. In the 'ex works' state directionality of the mechanical properties has been raised lately as a new issue worth checking. Within the projected evolutionary path two events have been especially considered; seismic events and glaciation. A glacier 2 km thick would increase the hydrostatic pressure with 20 MPa if there were a mechanism transmitting the load into the aqueous phase. Remembering what makes ice skating possible such a mechanism seems plausible. For mechanical overload the critical state is relatively straightforward to

General aspects of the mechanical integrity of canisters

Energy Technology Data Exchange (ETDEWEB)

Saario, Timo [VTT Materials and Building (Finland)

2007-09-15

This paper attempts to introduce a new point of view to the mechanical integrity of the canisters, 'mechanical integrity evolutionary path'. The mechanical integrity evolutionary path is a description of development of the critical parameters involved in the prevailing degradation modes as a function of time. The degradation mechanisms considered are: mechanical overload; creep; and stress corrosion cracking. For each degradation mechanism one may consider two different states; initial state; critical state. The initial state considered will be different for different degradation mechanisms. For example stress corrosion cracking (SCC), which involves electrochemical steps is not possible without a surface covering aqueous phase. Thus, potentially, the initial state for SCC is that existing after saturation. On the other hand, the initial state for a possible mechanical overload can be different in different periods during the mechanical integrity evolutionary path. During the handling and transport stages the initial state is 'ex works', while during a glaciation the initial state has been altered due to creep, corrosion and possible SCC processes. The canister will go through mechanical overload during saturation and bentonite swelling phases and it will deform to fit the form of the insert. The initial state for this period is 'ex works', with e.g. manufacturing defects. The insert is designed to bear the load after closing the gap. In the 'ex works' state directionality of the mechanical properties has been raised lately as a new issue worth checking. Within the projected evolutionary path two events have been especially considered; seismic events and glaciation. A glacier 2 km thick would increase the hydrostatic pressure with 20 MPa if there were a mechanism transmitting the load into the aqueous phase. Remembering what makes ice skating possible such a mechanism seems plausible. For mechanical overload the critical

Evaluation of salt particle collection device for preventing SCC on canister - Effect on particle collection rate by electric field

International Nuclear Information System (INIS)

Takeda, H.; Saegusa, T.

2013-01-01

Now, in Japan, while metal casks are used for spent nuclear fuel storage, a practical use of concrete casks is under review because of its cost effectiveness and procurement easiness. In reviewing the practical use, stress corrosion cracking (SCC) of a canister container in the concrete cask becomes an issue and is needed to be resolved soon. A natural ventilation system is generally adopted for the storage facilities, especially in Japan where facilities are built near coasts so that the cooling air includes sea salt particles. Therefore, the occurrence of SCC is concerned when the sea salt particles adhere to welded parts of the canisters. In this study, we proposed a salt particle collection device with low pressure loss which does not interfere with the air flow into the building or the concrete casks. The device is composed of a stack of 10 parallel stainless steel plates, the air is free to circulate in the space between them. Pressure loss tests in a laboratory and salt particle collection tests in the field have been performed. It has been clarified that the pressure loss of the device is one-thirtieth to one-twentieth of that of a commercial filter and 40% of the particles in the air could be collected and the device would not influence the heat removal performance. Moreover, we evaluated the effect of electric field on the particle collection under supposing the particle charge. In the case of electric field over 10 3 kV/m the particle collection rate could be improved dramatically

Microstructure, mechanical properties and stress corrosion cracking of Al–Zn–Mg–Zr alloy sheet with trace amount of Sc

Energy Technology Data Exchange (ETDEWEB)

Huang, Xing [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Pan, Qinglin, E-mail: pql1964@126.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Li, Bo [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Liu, Zhiming; Huang, Zhiqi [Guangdong Fenglu Aluminum Co., Ltd, Foshan 528133 (China); Yin, Zhimin [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)

2015-11-25

Microstructural and property evolution of the Al–Zn–Mg–0.10%Sc–0.10%Zr alloy sheet during its preparation were investigated in detail by means of optical microscopy (OM), scanning electron microscope (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), Vickers micro-hardness test and room temperature tensile test. Stress corrosion cracking (SCC) behavior of the Al–Zn–Mg–0.10%Sc–0.10%Zr alloy under different heat treatments was studied using slow strain rate test. The results showed that serious dendritic segregation existed in as-cast condition. The suitable homogenization treatment for Al–Zn–Mg–0.10%Sc–0.10%Zr alloy was 470 °C/24 h. After homogenization treatment, dissoluble Zn and Mg enriched non-equilibrium phases dissolved into α-Al matrix completely. The suitable solid solution-aging treatment for Al–Zn–Mg–0.10%Sc–0.10%Zr alloy was solution treated at 470 °C for 60 min, followed by water quenching and then aged at 120 °C for 24 h. Under this aging temper, the grain structures were composed of sub-grains, η′ phases and nanometer-sized, spherical Al{sub 3}(Sc, Zr) particles. Grain boundary precipitates (GBPs) area fraction was found to be an important parameter to evaluate the SCC susceptibility. The improved corrosion resistance from increasing aging temperature or prolonging aging time was due to the discontinuous η precipitates along the grain boundary and the high area fraction of GBPs. The main strengthening mechanisms of Al–Zn–Mg–0.10%Sc–0.10%Zr alloy are precipitation strengthening derived from η′ precipitates, dispersion strengthening, sub-grain strengthening and grain refinement caused by coherent Al{sub 3}(Sc, Zr) particles. - Highlights: • The suitable homogenization treatment of the alloy has been identified. • Evolution of microstructure and mechanical properties is investigated. • Strengthening mechanisms of the alloy has been established. • The basic mechanism has

Effect of cold work and processing orientation on the SCC behavior of Alloy 600

International Nuclear Information System (INIS)

Moshier, W.C.; Brown, C.M.

1999-01-01

Cold work accelerates SCC growth rates in Alloy 600. However, the variation in crack growth rates generated from cold worker material has been significant, and the effect has been difficult to quantify. A study was performed in hydrogenated water adjusted to pH 10.2 to systematically evaluate the effect of cold work on Alloy 600 as a function of temperature, amount of cold work, stress intensity factor, and processing orientation. Cold work was introduced into the material by either tensile prestraining or cold rolling plate product. Crack growth rates were determined between 252 and 360 C, stress intensity factors between 21 and 55 MPa√m, and yield strengths between 201 and 827 MPa. The material with the highest yield strength was cold rolled and tested in the longitudinal-transverse (LT) and short-transverse (ST) orientations. Crack growth rates increased with increasing temperature, stress intensity factor, and yield strength. Furthermore, crack growth rates were a strong function of the processing orientation in the cold rolled plate, with growth rates being approximately an order of magnitude greater in the ST orientation compared to the LT orientation. Crack growth rates in the LT orientation were measured between 0.003 and 1.95 x 10 -9 m/s and between 0.066 and 6.3 x 10 -9 m/s in the ST orientation. Activation energies were slightly greater in the ST orientation, ranging from 154 to 191 kcal/mole, compared to activation energies between 126 and 157 kJ/mole in the LT orientation. The results of this study demonstrate that although cold work can be used to accelerate SCC, the orientation of crack growth can significantly affect the results, and must be taken into account when analyzing data from cold worked material

NSE, CEA and SCC - a useful combination of tumor markers in lung cancer

International Nuclear Information System (INIS)

Fischbach, W.; Jany, B.

1988-01-01

The usefulness of neuronspecific enolase (NSE), CEA, and of the tumor associated antigen SSC was investigated in 61 patients with histologically proven lung cancer (small cell lung cancer n=25, adenocarcinoma n=14, squamous cell carcinoma n=18 and large cell carcinoma n=4). The sensitivity of NSE was 93.3% in small cell lung cancer (SCLC), whereas in adeno- and squamous cell carcinoma only 8 or 13%, resp., elevated serum NSE were found. CEA was the most sensitive marker for adenocarcinoma (58.3%). Contrary to NSE, however, CEA does not allow any conclusions concerning differential diagnosis as pathological serum concentrations were also observed in 46.6% both in small cell lung cancer and in squamous cell carcinoma. SCC demonstrated a sensitivity of 53% in squamous cell carcinoma. Elevated serum levels were also found in adenocarcinoma (41.6%), but never in small lung cancer. For all three markers tested, high serum concentrations were predominantly present in patients with advanced disease state. (orig.) [de

Clinical significance of measurement of changes of serum IGF-II, SCC and CYFRA21-1 levels after operation in patients with carcinoma of uterine cervix

International Nuclear Information System (INIS)

Kuang Lei

2010-01-01

Objective: To explore the clinical significance of changes of serum IGF-II, SCC and CYFRA21-1 levels after operation in patients with carcinoma uterine cervix. Methods: Serum levels of IGF-II, SCC and CYFRA21-1 were determined with RIA repeatedly in 31 patients with carcinoma of uterine cervix (before operation 1 month after operation and 6 month after operation) and once in 35 controls. Results: Before operation,serum levels of IGF-II, SCC and CYFRA21-1 in the patients were significantly higher than those in the controls (P<0.01). One month after operation all the serum levels were approaching normal. Six month later,the levels in the patients without recurrence remained normal. However, the levels in the 6 patients with recurrence returned to those before operation again. Conclusion: Changes of serum IGF-II, SCC and CYFRA21-1 levels are closely related to the tumor burden and may be of prognostic importance. (authors)

Thermally activated low temperature creep and primary water stress corrosion cracking of NiCrFe alloys

International Nuclear Information System (INIS)

Hall, M.M. Jr.

1993-01-01

A phenomenological SCC-CGR model is developed based on an apriori assumption that the SCC-CGR is controlled by low temperature creep (LTC). This mode of low temperature time dependent deformation occurs at stress levels above the athermal flow stress by a dislocation glide mechanism that is thermally activated and may be environmentally assisted. The SCC-CGR model equations developed contain thermal activation parameters descriptive of the dislocation creep mechanism. Thermal activation parameters are obtained by fitting the CGR model to SCC-CGR data obtained on Alloy 600 and Alloy X-750. These SCC-CGR activation parameters are compared to LTC activation parameters obtained from stress relaxation tests. When the high concentration of hydrogen at the tip of an SCC crack is considered, the SCC-CGR activation energies and rate sensitivities are shown to be quantitatively consistent with hydrogen reducing the activation energy and increasing the strain rate sensitivity in LTC stress relaxation tests. Stress dependence of SCC-CGR activation energy consistent with that found for the LTC activation energy. Comparisons between temperature dependence of the SCC-CGR stress sensitivity and LTC stress sensitivity provide a basis for speculation on effects of hydrogen and solute carbon on SCC crack growth rates

Fabrication of irradiation capsule for IASCC irradiation tests (2). Irradiation capsule for crack propagation test (Joint research)

International Nuclear Information System (INIS)

Ide, Hiroshi; Matsui, Yoshinori; Kawamata, Kazuo; Taguchi, Taketoshi; Kanazawa, Yoshiharu; Onuma, Yuichi; Watanabe, Hiroyuki; Inoue, Shuichi; Izumo, Hironobu; Ishida, Takuya; Saito, Takashi; Ishitsuka, Etsuo; Kawamura, Hiroshi; Kaji, Yoshiyuki; Ugachi, Hirokazu; Tsukada, Takashi

2008-03-01

It is known that irradiation Assisted Stress Corrosion Cracking (IASCC) occurs when austenitic stainless steel components used for light water reactor (LWR) are irradiated for a long period. In order to evaluate the high aging of the nuclear power plant, the study of IASCC becomes the important problem. The specimens irradiated in the reactor were evaluated by post irradiation examination in the past study. For the appropriate evaluation of IASCC, it is necessary to test it under the simulated LWR conditions; temperature, water chemistry and irradiation conditions. In order to perform in-pile SCC test, saturated temperature capsule (SATCAP) was developed. There are crack growth test, crack propagation test and so on for in-pile SCC test. In this report, SATCAP for crack propagation test is reported. (author)

Fabrication of irradiation capsule for IASCC irradiation tests (1). Irradiation capsule for crack growth test (Joint research)

International Nuclear Information System (INIS)

Ide, Hiroshi; Matsui, Yoshinori; Kawamata, Kazuo; Taguchi, Taketoshi; Kanazawa, Yoshiharu; Onuma, Yuichi; Watanabe, Hiroyuki; Inoue, Shuichi; Izumo, Hironobu; Ishida, Takuya; Saito, Takashi; Ishitsuka, Etsuo; Kawamura, Hiroshi; Kaji, Yoshiyuki; Ugachi, Hirokazu; Tsukada, Takashi

2008-03-01

It is known that Irradiation Assisted Stress Corrosion Cracking (IASCC) occurs when austenitic stainless steel components used for light water reactor (LWR) are irradiated for a long period. In order to evaluate the high aging of the nuclear power plant, the study of IASCC becomes the important problem. The specimens irradiated in the reactor were evaluated by post irradiation examination in the past study. For the appropriate evaluation of IASCC, it is necessary to test it under the simulated LWR conditions; temperature, water chemistry and irradiation conditions. In order to perform in-pile SCC test, saturated temperature capsule (SATCAP) was developed. There are crack growth test, crack propagation test and so on for in-pile SCC test. In this report, SATCAP for crack growth test is reported. (author)

Test techniques for fracture mechanics testing

International Nuclear Information System (INIS)

Schwalbe, K.H.

1980-01-01

Test methods for fracture mechanics tests are described. Two groups of techniques are distinguished: Those for measurement of stable crack growth and those for determination of the loading parameters. (orig.) [de

Constant extension rate testing of Type 304L stainless steel in simulated waste tank environments

International Nuclear Information System (INIS)

Wiersma, B.J.

1992-01-01

New tanks for storage of low level radioactive wastes will be constructed at the Savannah River Site (SRS) of AISI Type 304L stainless steel (304L). The presence of chlorides and fluorides in the wastes may induce Stress Corrosion Cracking (SCC) in 304L. Constant Extension Rate Tests (CERT) were performed to determine the susceptibility of 304L to SCC in simulated wastes. In five of the six tests conducted thus far 304L was not susceptible to SCC in the simulated waste environments. Conflicting results were obtained in the final test and will be resolved by further tests. For comparison purposes the CERT tests were also performed with A537 carbon steel, a material similar to that utilized for the existing nuclear waste storage tanks at SRS

Stress corrosion cracking susceptibility of austenitic stainless steels in supercritical water conditions

International Nuclear Information System (INIS)

Novotny, R.; Haehner, P.; Ripplinger, S.; Siegl, J.; Penttilae, Sami; Toivonen, Aki

2009-01-01

Within the 6th Framework Program HPLWR-2 project (High Performance Light Water Reactor - Phase 2), stress corrosion cracking (SCC) susceptibilities of selected austenitic stainless steels, 316L and 316NG, were studied in supercritical water (SCW) with the aim to identify and describe the specific failure mechanisms prevailing during slow strain-rate tensile (SSRT) tests in ultra-pure demineralised SCW water solution. The SSRT tests were performed using a step-motor controlled loading device in an autoclave at 350 deg. C, 500 deg. C and 550 deg. C. Besides water temperature, the pressure, the oxygen content and the strain rate (resp. crosshead speed) were varied in the series of tests. The specimens SSRT tested to failure were subjected to fractographic analysis, in order to characterise the failure mechanisms. The fractography confirmed that failure was due to a combination of transgranular SCC and transgranular ductile fracture. The share of SCC and ductile fracture in the failure process of individual specimens was affected by the parameters of the SSRT tests, so that the environmental influence on SCC susceptibility could be assessed, in particular, the SCC sensitising effects of increasing oxygen content, decreasing strain rate and increasing test temperature. (author)

Liderazgo de una empresa familiar que influye en el clima laboral de los trabajadores de la empresa SEDEMI S.C.C

OpenAIRE

Rodríguez Valenzuela, Darwin Fausto

2015-01-01

El presente trabajo detalla el estudio del liderazgo y su influencia en el clima organizacional de los trabajadores de la empresa familiar Sedemi S.C.C., con la fin de proponer opciones de mejora, que coadyuven al directorio de la empresa, para fomentar un ambiente laboral agradable y motivador para sus empleados, y de esta manera incrementar su desempeño laboral. La investigación se realizó en la empresa SEDEMI S.C.C. La población objetivo está conformada por los empleados administrativos y ...

dK/da effects on the SCC growth rates of nickel base alloys in high-temperature water

Science.gov (United States)

Chen, Kai; Wang, Jiamei; Du, Donghai; Andresen, Peter L.; Zhang, Lefu

2018-05-01

The effect of dK/da on crack growth behavior of nickel base alloys has been studied by conducting stress corrosion cracking tests under positive and negative dK/da loading conditions on Alloys 690, 600 and X-750 in high temperature water. Results indicate that positive dK/da accelerates the SCC growth rates, and the accelerating effect increases with dK/da and the initial CGR. The FRI model was found to underestimate the dK/da effect by ∼100X, especially for strain hardening materials, and this underscores the need for improved insight and models for crack tip strain rate. The effect of crack tip strain rate and dK/dt in particular can explain the dK/da accelerating effect.

Verification of intraspecimen method using constant stress tension test of sensitized alloy 600

International Nuclear Information System (INIS)

Lee, Seung Ki; Choi, Hoi Su; Hwang, Il Soon

2005-01-01

Stress corrosion cracking (SCC) occurring at the Nibase alloy 600 used in the nuclear power plant SG tubes and CRDM penetration nozzles had been reported after long-term operation in the harsh environment. Intraspecimen method was developed to predict the SCC initiation time statistically. [1] By dividing a test area into a number of smaller regions (intraspecimens) having homogeneous physical and chemical condition each SCC initiation in each intraspecimen could be counted as an independent outcome to provide enough number of statistical data. Earlier work of intraspecimen method had many problems in test method and didn't agree with Weibull statistics which is the theoretical base of intraspecimen method. The test method is improved in this intraspecimen test. To find out the root causes of the problems in earlier work and improve the accuracy of intraspecimen method, two kinds of materials are introduced, which are different in grain size but same in chemical composition. Ni-base alloy 600, heat no. J313 and J323 are used as test materials. Specimens of sensitized Alloy 600 are tested under the condition of constant tensile stress and well defined chemical environment therefore we can easily observe typical intergranular stress corrosion cracking (IGSCC). Material with finer grain (J323) showed the areadependence in agreement with theoretical prediction. But material with coarser grain (J313) did not show any significant area-dependence. While SCC initiates earlier at grain boundaries that are oriented close to normal to the stress axis, crack initiation time showed no correlation with grain boundary misorientation estimated by Electron Back Scattered Diffraction (EBSD). From the SCC initiation tests with two test materials, it is concluded that the number of grains in an intraspecimen, degree of sensitization and uniform stress distribution are important parameters to meet Weibull statistics

Anti-Cancer Effects of Imperata cylindrica Leaf Extract on Human Oral Squamous Carcinoma Cell Line SCC-9 in Vitro.

Science.gov (United States)

Keshava, Rohini; Muniyappa, Nagesh; Gope, Rajalakshmi; Ramaswamaiah, Ananthanarayana Saligrama

2016-01-01

Imperata cylindrica, a tall tufted grass which has multiple pharmacological applications is one of the key ingredients in various traditional medicinal formula used in India. Previous reports have shown that I. cylindrica plant extract inhibited cell proliferation and induced apoptosis in various cancer cell lines. To our knowledge, no studies have been published on the effect of I. cylindrica leaf extract on human oral cancers. The present study was undertaken in order to evaluate the anticancer properties of the leaf extract of I. cylindrica using an oral squamous cell carcinoma cell line SCC-9 as an in vitro model system. A methanol extract from dried leaves of I. cylindrica (ICL) was prepared by standard procedures. Effects of the ICL extract on the morphology of SCC-9 cells was visualized by microscopy. Cytotoxicity was determined by MTT assay. Effects of the ICL extract on colony forming ability of SCC-9 cells was evaluated using clonogenic assay. Cell cycle analysis was performed by flow cytometry and induction of apoptosis was determined by DNA fragmentation assay. The ICL extract treatment caused cytotoxicity and induced cell death in vitro in SCC-9 cells in a dose-dependent manner. This treatment also significantly reduced the clonogenic potential and inhibited cell proliferation by arresting the cell cycle in the G2/M phase. Furthermore, DNA fragmentation assays showed that the observed cell death was caused by apoptosis. This is the first report showing the anticancer activity of the methanol extracts from the leaves of I. cylindrica in human oral cancer cell line. Our data indicates that ICL extract could be considered as one of the lead compounds for the formulation of anticancer therapeutic agents to treat/manage human oral cancers. The natural abundance of I. cylindrica and its wide geographic distribution could render it one of the primary resource materials for preparation of anticancer therapeutic agents.

CEA, SCC and NSE levels in exhaled breath condensate--possible markers for early detection of lung cancer.

Science.gov (United States)

Zou, Yingchang; Wang, Lin; Zhao, Cong; Hu, Yanjie; Xu, Shan; Ying, Kejing; Wang, Ping; Chen, Xing

2013-12-01

Lung cancer (LC) is the leading cause of cancer-related death. The sensitive and non-invasive diagnostic tools in the early stage are still poor. We present a pilot study on the early diagnosis of LC by detecting markers in exhaled breath condensate (EBC). EBC samples were collected from 105 patients with LC and 56 healthy controls. We applied chemiluminescence immunoassay to detect CEA (carcinoembryonic antigen), SCC (squamous cell carcinoma) antigen and NSE (neuron specific enolase) in EBC and serum. Concentrations of markers were compared between independent groups and subgroups. A significantly higher concentration level of each marker was found in patients with LC than healthy controls. The areas under curve of receiver operating characteristic (ROC) curves were 0.800, 0.771, 0.659, 0.679, 0.636 and 0.626 for EBC-CEA, serum-CEA, EBC-SCC, serum-SCC, EBC-NSE and serum-NSE, respectively. Markers in EBC had a higher positive rate (PR) and were more specific to histologic types than markers in serum. In addition, multivariate analysis was performed to evaluate the association of presenting markers with the stages of non-small cell lung cancer (NSCLC). EBC-CEA showed the best predictive characteristic (p tumor markers in EBC may have a better diagnostic performance for LC than those in serum. With further investigation on the combination of markers in EBC, detection of EBC could probably be a novel and non-invasive method to detect NSCLC earlier.

Chemical inhomogeneity populations in various zircaloy claddings and their association with SCC and corrosion resistance

International Nuclear Information System (INIS)

Tasooji, A.; Miller, A.K.; Cheung, T.Y.; Brooks, M.; Santucci, J.

1987-01-01

A technique has been developed that permits detection and characterization of sparsely distributed chemical inhomogeneities in Zircaloy. These inhomogeneities have previously been observed at the origins of iodine stress-corrosion cracks but are not detectable by, for example, simple scanning electron microscopy (SEM) examination. The technique uses radioactive iodine to ''label'' the chemical inhomogeneities, autoradiography to detect their locations, and SEM and energy-dispersive X-ray analysis (EDAX) to further characterize them. Large areas of surface have been surveyed and statistically meaningful populations of chemical inhomogeneities measured for five different lots of Zircaloy cladding. Inner surfaces and cladding cross-sectional surfaces have been studied. There are clear differences in chemical inhomogeneity size distribution and composition between the various claddings. For three of the claddings characterized in this work, the previously measured stress-corrosion cracking (SCC) threshold stresses correlate well (inversely) with the new data on their average chemical inhomogeneity sizes. Of special interest is the fact that the most SCC-resistant cladding contains far fewer iron-bearing inhomogeneities than the other claddings

Corrosion testing of type 304L stainless steel in tuff groundwater environments

International Nuclear Information System (INIS)

Westerman, R.E.; Pitman, S.G.; Haberman, J.H.

1987-11-01

The stress-corrosion cracking (SCC) resistance of Type 304L stainless steel (SS) to elevated temperatures in tuff rock and tuff groundwater environments was determined under irradiated and nonirradiated conditions using U-bend specimens and slow-strain-rate tests. The steel was tested both in the solution-annealed condition and after sensitization heat treatments. The material was found to be susceptible to SCC in both the solution-annealed and solution-annealed-and-sensitized conditions when exposed to an irradiated crushed tuff rock environment containing air and water vapor at 90 0 C. A similar exposure at 50 0 C did not result in failure after a 25-month test duration. Specimens of sensitized 304 SS conditioned with a variety of sensitization heat treatments resisted failure during a test of 1-year duration in which a nonirradiated environment of tuff rock and groundwater held at 200 0 C was allowed to boil to dryness on a cyclical basis. All specimens of sensitized 304 SS exposed to this environment failed. Slow-strain-rate studies were performed on 304L, 304, and 316L SS specimens. The 304L SS was tested in J-13 well water at 150 0 C, and the 316L SS at 95 0 C. Neither material showed evidence of SCC in these tests. Sensitized 304 SS did exhibit SCC in J-13 well water in tests conducted at 150 0 C. 12 refs., 27 figs., 13 tabs

Precursor evolution and SCC initiation of cold-worked alloy 690 in simulated PWR primary water

Energy Technology Data Exchange (ETDEWEB)

Zhai, Ziqing; Kruska, Karen; Toloczko, Mychailo B.; Bruemmer, Stephen M.

2017-03-27

Stress corrosion crack initiation of two thermally-treated, cold-worked (CW) alloy 690 materials was investigated in 360oC simulated PWR primary water using constant load tensile (CLT) tests and blunt notch compact tension (BNCT) tests equipped with direct current potential drop (DCPD) for in-situ detection of cracking. SCC initiation was not detected by DCPD for the 21% and 31%CW CLT specimens loaded at their yield stress after ~9,220 h, however intergranular (IG) precursor damage and isolated surface cracks were observed on the specimens. The two 31%CW BNCT specimens loaded at moderate stress intensity after several cyclic loading ramps showed DCPD-indicated crack initiation after 10,400h exposure at constant stress intensity, which resulted from significant growth of IG cracks. The 21%CW BNCT specimens only exhibited isolated small IG surface cracks and showed no apparent DCPD change throughout the test. Interestingly, post-test cross-section examinations revealed many grain boundary (GB) nano-cavities in the bulk of all the CLT and BNCT specimens particularly for the 31%CW materials. Cavities were also found along GBs extending to the surface suggesting an important role in crack nucleation. This paper provides an overview of the evolution of GB cavities and will discuss their effects on crack initiation in CW alloy 690.

In-Pile Tests for IASCC Growth Behavior of Irradiated 316L Stainless Steel under Simulated BWR Condition in JMTR

Science.gov (United States)

Chimi, Yasuhiro; Kasahara, Shigeki; Ise, Hideo; Kawaguchi, Yoshihiko; Nakano, Junichi; Nishiyama, Yutaka

The Japan Atomic Energy Agency (JAEA) has an in-pile irradiation test plan to evaluate in-situ effects of neutron/γ-ray irradiation on stress corrosion crack (SCC) growth of irradiated stainless steels using the Japan Materials Testing Reactor (JMTR). SCC growth rate and its dependence on electrochemical corrosion potential (ECP) are different between in-pile test and post irradiation examination (PIE). These differences are not fully understood because of a lack of in-pile data. This paper presents a systematic review on SCC growth data of irradiated stainless steels, an in-pile test plan for crack growth of irradiated SUS316L stainless steel under simulated BWR conditions in the JMTR, and the development of the in-pile test techniques.

Effect of controlled potential on SCC of nuclear waste package container materials

International Nuclear Information System (INIS)

Lum, B. Y.; Roy, A. K.; Spragge, M. K.

1999-01-01

The slow-strain-rate (SSR) test technique was used to evaluate the susceptibility of Titanium (Ti) Gr-7 (UNS R52400) and Ti Gr-12 (UNS R53400) to stress corrosion cracking (SCC). Ti Gr-7 and Ti Gr-12 are two candidate container materials for the multi-barrier package for nuclear waste. The tests were done in a deaerated 90 C acidic brine (pH ∼ 2.7) containing 5 weight percent (wt%) sodium chloride (NaCl) using a strain rate of 3.3 x 10 -6 sec -1 . Before being tested in the acidic brine, specimens of each alloy were pulled inside the test chamber in the dry condition at ambient temperature. Then while in the test solution, specimens were strained under different cathodic (negative) controlled electrochemical potentials. These controlled potentials were selected based on the corrosion potential measured in the test solution before the specimens were strained. Results indicate that the times to failure (TTF) for Ti Gr-12 were much shorter than those for Ti Gr-7. Furthermore, as the applied potential became more cathodic, Ti Gr-12 showed reduced ductility in terms of percent reduction in area (%RA) and true fracture stress (σ f ). In addition, TTF and percent elongation (%El) reached the minimum values when Ti Gr-12 was tested under an impressed potential of -1162 mV. However, for Ti Gr-7, all these ductility parameters were not significantly influenced by the changes in applied potential. In general, the results of hydrogen analysis by secondary ion mass spectrometry (SIMS) showed increased hydrogen concentration at more cathodic controlled potentials. Optical microscopy and scanning electron microscopy (SEM) were used to evaluate the morphology of cracking both at the primary fracture face and the secondary cracks along the gage section of the broken tensile specimen. Transgranular secondary cracks were observed in both alloys possibly resulting from the formation of brittle titanium hydrides due to cathodic charging. The primary fracture face was characterized

Effect of sulfur on the SCC and corrosion fatigue performance of stainless steel

International Nuclear Information System (INIS)

West, E.; Nolan, T.; Lucente, A.; Morton, D.; Lewis, N.; Morris, R.; Mullen, J.; Newsome, G.

2015-01-01

Stress corrosion cracking and corrosion fatigue experiments were conducted on model heats of 304/304L stainless steel with systematically controlled sulfur content to isolate the influence of sulfur on crack growth behavior. The results of the SCC experiments conducted in 338 C. degrees deaerated water on 20% cold worked model heats with 0.006 and 0.012 wt% sulfur showed an order of magnitude or more reduction in the crack growth rate relative to a model heat with <0.001 wt% sulfur. Corrosion fatigue crack growth rates revealed a reduction in the crack growth rates of the elevated sulfur heats relative to model predicted steady state crack growth rates with increasing rise time for nominal loading conditions of a stress ratio of 0.7 and a stress intensity factor range of 6.6 MPa√m. At the longest rise time of 5.330 sec, the corrosion fatigue crack growth rate of the 0.006 wt% sulfur model heat was only 13% of model predictions and the crack growth of the 0.012 wt% sulfur heat completely stalled. Experiments conducted in anion faulted aerated water on stainless steel heats with moderate to high sulfur and variable carbon and boron contents showed that any detrimental effect of sulfur in this environment was secondary to the effect of sensitization in promoting SCC growth. (authors)

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)

Helium leak testing the Westinghouse LCP coil

International Nuclear Information System (INIS)

Merritt, P.A.; Attaar, M.H.; Hordubay, T.D.

1983-01-01

The tests, equipment, and techniques used to check the Westinghouse LCP coil for coolant flow path integrity and helium leakage are unique in terms of test sensitivity and application. This paper will discuss the various types of helium leak testing done on the LCP coil as it enters different stages of manufacture. The emphasis will be on the degree of test sensitivity achieved under shop conditions, and what equipment, techniques and tooling are required to achieve this sensitivity (5.9 x 10 -8 scc/sec). Other topics that will be discussed are helium flow and pressure drop testing which is used to detect any restrictions in the flow paths, and the LCP final acceptance test which is the final leak test performed on the coil prior to its being sent for testing. The overall allowable leak rate for this coil is 5 x 10 -6 scc/sec. A general evaluation of helium leak testing experience are included

Testing Mechanisms for Philanthropic Behaviour

NARCIS (Netherlands)

Bekkers, R.H.F.P.; Wiepking, P.

2011-01-01

This special issue of the International Journal of Nonprofit and Voluntary Sector Marketing presents a collection of nine papers testing mechanisms that drive philanthropic behaviour. By testing one or more specific mechanisms that were derived from the philanthropic literature, the authors of the

Degradation of self-compacting concrete (SCC) due to sulfuric acid attack: Experiment investigation on the effect of high volume fly ash content

Science.gov (United States)

Kristiawan, S. A.; Sunarmasto; Tyas, G. P.

2016-02-01

Concrete is susceptible to a variety of chemical attacks. In the sulfuric acid environment, concrete is subjected to a combination of sulfuric and acid attack. This research is aimed to investigate the degradation of self-compacting concrete (SCC) due to sulfuric acid attack based on measurement of compressive strength loss and diameter change. Since the proportion of SCC contains higher cement than that of normal concrete, the vulnerability of this concrete to sulfuric acid attack could be reduced by partial replacement of cement with fly ash at high volume level. The effect of high volume fly ash at 50-70% cement replacement levels on the extent of degradation owing to sulfuric acid will be assessed in this study. It can be shown that an increase in the utilization of fly ash to partially replace cement tends to reduce the degradation as confirmed by less compressive strength loss and diameter change. The effect of fly ash to reduce the degradation of SCC is more pronounced at a later age.

Metallurgical and mechanical parameters controlling alloy 718 stress corrosion cracking resistance in PWR primary water; Facteurs metallurgiques et mecaniques controlant l'amorcage de defauts de corrosion sous contrainte dans l'alliage 718 en milieu primaire des reacteurs a eau sous pression

Energy Technology Data Exchange (ETDEWEB)

Deleume, J

2007-11-15

Improving the performance and reliability of the fuel assemblies of the pressurized water reactors requires having a perfect knowledge of the operating margins of both the components and the materials. The choice of alloy 718 as reference material for this study is justified by the industrial will to identify the first order parameters controlling the excellent resistance of this alloy to Stress Corrosion Cracking (SCC). For this purpose, a specific slow strain rate (SSR) crack initiation test using tensile specimen with a V-shaped hump in the middle of the gauge length was developed and modeled. The selectivity of such SSR tests in simulated PWR primary water at 350 C was clearly established by characterizing the SCC resistance of nine alloy 718 thin strip heats. Regardless of their origin and in spite of a similar thermo-mechanical history, they did not exhibit the same susceptibility to SCC crack initiation. All the characterized alloy 718 heats develop oxide scale of similar nature for various exposure times to PWR primary medium in the temperature range [320 C - 360 C]. {delta} phase precipitation has no impact on alloy 718 SCC initiation behavior when exposed to PWR primary water, contrary to interstitial contents and the triggering of plastic instabilities (PLC phenomenon). (author)

Testing of nuclear grade lubricants and their effects on A540 B24 and A193 B7 bolting materials

International Nuclear Information System (INIS)

Czajkowski, C.J.

1985-01-01

An investigation was performed on eleven commonly used lubricants by the nuclear power industry. The investigation included EDS analysis of the lubricants, notched-tensile constant extension rate testing of bolting materials with the lubricants, frictional testing of the lubricants and weight loss testing of a bonded solid film lubricant. The report generally concludes that there is a significant amount of variance in the mechanical properties of common bolting materials; that MoS 2 can hydrolyze to form H 2 S at 100 0 C and cause stress corrosion cracking (SCC) of bolting materials, and that the use of copper-containing lubricants can be potentially detrimental to high strength steels in an aqueous environment. Additionally, the testing of various lubricants disclosed that some lubricants contain potentially detrimental elements (e.g. S, Sb) which can promote SCC of the common bolting materials. One of the most significant findings of this report is the observation that both A193 B7 and A540 B24 bolting materials are susceptible to transgranular stress corrosion cracking in demineralized H 2 O at 280 0 C in notched tensile tests

The stress-corrosion cracking behavior of high-strength aluminum powder metallurgy alloys

Science.gov (United States)

Pickens, J. R.; Christodoulou, L.

1987-01-01

The susceptibility to stress-corrosion cracking (SCC) of rapidly solidified (RS) aluminum powder metallurgy (P/M) alloys 7090 and 7091, mechanically alloyed aluminum P/M alloy IN* 9052, and ingot metallurgy (I/M) alloys of similar compositions was compared using bolt-loaded double cantilever beam specimens. In addition, the effects of aging, grain size, grain boundary segregation, pre-exposure embrittlement, and loading mode on the SCC of 7091 were independently assessed. Finally, the data generated were used to elucidate the mechanisms of SCC in the three P/M alloys. The IN 9052 had the lowest SCC susceptibility of all alloys tested in the peak-strength condition, although no SCC was observed in the two RS alloys in the overaged condition. The susceptibility of the RS alloys was greater in the underaged than the peak-aged temper. We detected no significant differences in susceptibility of 7091 with grain sizes varying from 2 to 300 μm. Most of the crack advance during SCC of 7091 was by hydrogen embrittlement (HE). Furthermore, both RS alloys were found to be susceptible to preexposure embrittlement—also indicative of HE. The P/M alloys were less susceptible to SCC than the I/M alloys in all but one test.

Accelerated testing of space mechanisms

Science.gov (United States)

Murray, S. Frank; Heshmat, Hooshang

1995-01-01

This report contains a review of various existing life prediction techniques used for a wide range of space mechanisms. Life prediction techniques utilized in other non-space fields such as turbine engine design are also reviewed for applicability to many space mechanism issues. The development of new concepts on how various tribological processes are involved in the life of the complex mechanisms used for space applications are examined. A 'roadmap' for the complete implementation of a tribological prediction approach for complex mechanical systems including standard procedures for test planning, analytical models for life prediction and experimental verification of the life prediction and accelerated testing techniques are discussed. A plan is presented to demonstrate a method for predicting the life and/or performance of a selected space mechanism mechanical component.

The hardness test: a real mechanical test

International Nuclear Information System (INIS)

Rezakhanlou, R.

1993-02-01

During the service life, the mechanical properties of the PWR components change. It is necessary to determine precisely this evolution, but it is not always possible to draw a sample with the adequate size for the characterization. For this latter case we intend to calculate the stress-strain curve of a material from a hardness test results, because it is appropriate for testing on site and do not need any particular sample shape. This paper is the first bibliographical part of a larger study on the relation between the values measured during a hardness test (applied load, indentation diameter) and the mechanical properties of a solid obtained by a traction test. We have treated the problem within the general setting of two solids in contact. Thus, we expose general elastic, elasto-plastic and plastic models describing the indentation of a solid by a rigid indenter

Modelling of stress corrosion cracking in zirconium alloys

International Nuclear Information System (INIS)

Fandeur, O.; Rouillon, L.; Pilvin, P.; Jacques, P.; Rebeyrolle, V.

2001-01-01

During normal and incidental operating conditions, PWR power plants must comply with the first safety requirement, which is to ensure that the cladding wall is sound. Indeed some severe power transients potentially induce Stress Corrosion Cracking (SCC) of the zirconium alloy clad, due to strong Pellet Cladding Interaction (PCI). Since, at present, the prevention of this risk has some consequences on the French reactors manoeuvrability, a better understanding and forecast of the clad damage related to SCC/PCI is needed. With this aim, power ramp tests are performed in experimental reactors to assess the fuel rod behaviour and evaluate PCI failure risks. To study in detail SCC mechanisms, additional laboratory experiments are carried out on non-irradiated and irradiated cladding tubes. Numerical simulations of these tests have been developed aiming, on the one hand, to evaluate mechanical state variables and, on the other hand, to study consistent mechanical parameters for describing stress corrosion clad failure. The main result of this simulation is the determination of the validity ranges of the stress intensity factor, which is frequently used to model SCC. This parameter appears to be valid only at the onset of crack growth, when crack length remains short. In addition, the role of plastic strain rate and plastic strain as controlling parameters of the SCC process has been analysed in detail using the above mechanical description of the crack tip mechanical fields. Finally, the numerical determination of the first-order parameter(s) in the crack propagation rate law is completed by the development of laboratory tests focused on these parameters. These tests aim to support experimentally the results of the FE simulation. (author)

An experimental survey on combined effects of fibers and nanosilica on the mechanical, rheological, and durability properties of self-compacting concrete

International Nuclear Information System (INIS)

Beigi, Morteza H.; Berenjian, Javad; Lotfi Omran, Omid; Sadeghi Nik, Aref; Nikbin, Iman M.

2013-01-01

Highlights: • We investigate combine effects of fibers and nanosilica on SCC. • The mechanical, rheological, and durability properties were tested and compared. • Microstructural properties of concrete were assessed using AFM and XRD techniques. • Nanosilica and fibers can improve the mechanical properties and durability of SCC. - Graphical abstract: - Abstract: Previous studies have shown that application of fibers in concrete enhances scratching, flexural and tensile strength. Self-Compacting Concrete (SCC) is a highly flowable and coherent concrete able to self-compact under its own weight. On the other hand, nanosilica particles and artificial pozzolans possessing high efficiency in concrete technology can improve structural properties of cement-based materials. Previous studies have suggested self-compacting and fiber-reinforced concretes for more stable and efficient buildings. Therefore, the present study aimed to evaluate the effects of nanosilica and different concrete reinforcing fibers including steel, polypropylene and glass on the performance of concrete. In this study mechanical (compressive, splitting tensile and flexural strength, toughness and modulus of elasticity), rheological (L-Box, slump flow, T50) and durability (resist chloride ion penetration (RCPT) and water absorption) properties are assessed. In addition, microstructural properties of concrete were assessed using Atomic Force Microscopy (AFM) and X-Ray Diffraction (XRD) techniques. Totally, 40 concrete mixes , labeled as A, B, C and D, with nanosilica contents of 0, 2, 4 and 6 weight percent (wt.%) of cement, respectively and three types of reinforcing fibers (steel: 0.2, 0.3 and 0.5 volume percent (v%) and polypropylene: 0.1, 0.15 and 0.2 v% and glass: 0.15, 0.2 and 0.3 v%) were evaluated. The results of the study showed that the presence of both nanosilica and reinforcing fibers in optimal percentages, can improve the mechanical properties and durability of self

Conserved vector current test/second class current search in the A = 8 isotriplet

International Nuclear Information System (INIS)

Snover, K.A.; Schagen, J.P.S. van; Storm, D.W.; Kelly, M.P.

2002-01-01

A new experiment is underway to make a precision determination of the isovector M1 and E2 decays of the 2 + isobaric analog resonance doublet in 8 Be for the purpose of an improved CVC/SCC test in the A = 8 isotriplet. Assuming CVC holds, our current sensitivity for SCC is at the level of 5% of weak magnetism. (author)

Shaking table testing of mechanical components

International Nuclear Information System (INIS)

Jurukovski, D.; Taskov, Lj.; Mamucevski, D.; Petrovski, D.

1995-01-01

Presented is the experience of the Institute of Earthquake Engineering and Engineering Seismology, Skopje, Republic of Macedonia in seismic qualification of mechanical components by shaking table testing. Technical data and characteristics for the three shaking tables available at the Institute are given. Also, for characteristic mechanical components tested at the Institute laboratories, basic data such as producer, testing investor, description of the component, testing regulation, testing equipment and final user of the results. (author)

Technical basis for hydrogen-water chemistry: Laboratory studies of water chemistry effects on SCC [stress-corrosion-cracking

International Nuclear Information System (INIS)

Kassner, T.F.; Ruther, W.E.; Soppet, W.K.

1986-10-01

The influence of different impurities, viz., oxyacids and several chloride salts, on the stress-corrosion-cracking (SCC) of sensitized Type 304 stainless steel (SS) was investigated in constant-extension-rate-tensile (CERT) tests in 289 0 C water at a low dissolved-oxygen concentration ( 0 C in low-oxygen environments with and without sulfate at low concentrations. In these experiments, the crack growth behavior of the materials was correlated with the type and concentration of the impurities and the electrochemical potentials of Type 304 SS and platinum electrodes in the simulated hydrogen-water chemistry environments. The information suggests that better characterization of water quality, through measurement of the concentrations of individual species (SO 4 2- , NO 3 - , Cu 2+ , etc.) coupled with measurements of the corrosion and redox potentials at high temperatures will provide a viable means to monitor and ultimately improve the performance of BWR system materials

SCC analysis of Alloy 600 tubes from a retired steam generator

Science.gov (United States)

Hwang, Seong Sik; Kim, Hong Pyo

2013-09-01

Steam generators (SG) equipped with Alloy 600 tubes of a Korean nuclear power plants were replaced with a new one having Alloy 690 tubes in 1998 after 20 years of operation. To set up a guide line for an examination of the other SG tubes, a metallographic examination of the defected tubes was carried out. A destructive analysis on 71 tubes was addressed, and a relation among the stress corrosion crack (SCC) defect location, defect depth, and location of the sludge pile was obtained. Tubes extracted from the retired SG were transferred to a hot laboratory. Detailed nondestructive analysis examinations were taken again at the laboratory, and the tubes were then destructively examined. The types and sizes of the cracks were characterized. The location and depth of the SCC were evaluated in terms of the location and height of the sludge. Most axial cracks were in the sludge pile, whereas the circumferential ones were around the top of the tube sheet (TTS) or below the TTS. Average defect depth of the axial cracks was deeper than that of the circumferential ones. Axial cracks at tube support plate (TSP) seem to be related with corrosion/sludge in crevice like at the TTS region. Circumferential cracks at TSP seem to be caused by tube denting at the upper part of the TSP. Tubes not having clear ECT signals for quantifying an ECT data-base. Tubes having no ECT signal. Tubes with a large ECT signal. Tubes with various types and sizes of flaws (primary water stress corrosion cracking (PWSCC), outside diameter stress corrosion cracking (ODSCC), Pit). Tubes with distinct PWSCC or ODSCC. Tubes were extracted from the RSG based on the field ECT with the criteria, and transferred to a hot laboratory at the Korea Atomic Energy Research Institute (KAERI) for destructive examination. A comprehensive ECT inspection was performed again at the hot laboratory to confirm the location of the cracks obtained from a field inspection. These exact locations of the defects were marked on the

Multi-channel mechanical test machine for HANARO (I)

International Nuclear Information System (INIS)

Song, M. S.; Choi, Y.; Cho, M. S.; Kim, B. G.; Kang, Y. H.

2004-01-01

Design and fabrication of multi-channel mechanical test machine is useful and important for the study of in-pile test of nuclear materials in HANARO. The dimension and shape of the multi-channel mechanical test machine should be fixed to a test reactor and their objectives. KAERI successfully developed a non-instrumented multi-channel mechanical test machine for material irradiation tests in a domestic research reactor, HANARO. This results in strongly stimulating and accelerating irradiation tests of materials in domestic industry and research fields with HANARO. Although various types of in-pile creep capsule were made for well installation in each test reactor, there is no in-pile creep multi-channel mechanical test machine for HANARO. Hence, the objectives of this study are to fabricate and test a multi-channel mechanical test machine of HANARO

Influence of aggressive media on the mechanical behavior of the uranium--0.20 wt % vanadium alloy the role of hydrogen embrittlement

International Nuclear Information System (INIS)

Arnould-Laurent, R.

The tests comprised tensile tests under constant load or up to the fracture point using cylindrical or flat, trapezoidal test pieces, tests in which disks were ruptured under gaseous pressure, and tenacity tests. The alloy was found to be sensitive to: (1) intrinsic brittleness (I.B.) due to dissolved residual hydrogen from the preparation stage. This manifested itself mainly by cracking at an elongation threshold of about 3 percent. (2) Cracking due to stress corrosion (S.C.C.) in the true sense, which is made possible under certain conditions by an imperfect passivation of the metal surface. The process is initiated either by the appearance of microcracks which appear at the surface, or by corrosion pits. (3) Generalized corrosion accelerated by the stress (S.A.C.), whose microscopic appearance is similar to that observed with corrosion under gaseous hydrogen. Below pH 2 there is no stress corrosion. Stress rupture tests in moist air at 80 and 100 0 C measure I.B. + S.C.C. under high stress, giving rise to short lifetimes. I.B. + S.C.C. + S.A.C., with S.A.C. predominant, occurs under lower stresses that give long lifetimes. Stress rupture tests measure at 20 and 60 0 C I.B. + S.C.C. with I.B. predominant. Under high stresses (short lifetimes) the magnitude of the S.C.C. component increases as the temperature increases. The most serious effects are those of S.A.C. at 80 and 100 0 C, and of I.B. at all temperatures. The way this alloy behaves can only be changed by an effective reduction in the quantity of residual hydrogen present, or by coatings that will in no case allow the ingress of hydrogen. 62 fig, 82 references, 15 tables

Role of failure-mechanism identification in accelerated testing

Science.gov (United States)

Hu, J. M.; Barker, D.; Dasgupta, A.; Arora, A.

1993-01-01

Accelerated life testing techniques provide a short-cut method to investigate the reliability of electronic devices with respect to certain dominant failure mechanisms that occur under normal operating conditions. However, accelerated tests have often been conducted without knowledge of the failure mechanisms and without ensuring that the test accelerated the same mechanism as that observed under normal operating conditions. This paper summarizes common failure mechanisms in electronic devices and packages and investigates possible failure mechanism shifting during accelerated testing.

SCC, Bowen's disease and BCC arising on chronic radiation dermatitis due to radiation therapy for tinea pedis

International Nuclear Information System (INIS)

Aoki, Eri; Aoki, Mikako; Ikemura, Akiko; Igarashi, Tsukasa; Suzuki, Kayano; Kawana, Seiji

2000-01-01

We reported a case who developed three different types of skin cancers: SCC, BCC, and Bowen's disease, on the chronic radiation dermatitis. He had been treated for his tinea pedis et palmaris with radiotherapy in 1940's. It is very ratre that three different types of skin cancers arise in the same patient. This is a second case reported in Japan. (author)

Comparison of ultrasound-assisted and traditional caustic leaching of spent cathode carbon (SCC) from aluminum electrolysis.

Science.gov (United States)

Xiao, Jin; Yuan, Jie; Tian, Zhongliang; Yang, Kai; Yao, Zhen; Yu, Bailie; Zhang, Liuyun

2018-01-01

The spent cathode carbon (SCC) from aluminum electrolysis was subjected to caustic leaching to investigate the different effects of ultrasound-assisted and traditional methods on element fluorine (F) leaching rate and leaching residue carbon content. Sodium hydroxide (NaOH) dissolved in deionized water was used as the reaction system. Through single-factor experiments and a comparison of two leaching techniques, the optimum F leaching rate and residue carbon content for ultrasound-assisted leaching process were obtained at a temperature of 70°C, residue time of 40min, initial mass ratio of alkali to SCC (initial alkali-to-material ratio) of 0.6, liquid-to-solid ratio of 10mL/g, and ultrasonic power of 400W, respectively. Under the optimal conditions, the leaching residue carbon content was 94.72%, 2.19% larger than the carbon content of traditional leaching residue. Leaching wastewater was treated with calcium chloride (CaCl 2 ) and bleaching powder and the treated wastewater was recycled caustic solution. All in all, benefiting from advantage of the ultrasonication effects, ultrasound-assisted caustic leaching on spent cathode carbon had 55.6% shorter residue time than the traditional process with a higher impurity removal rate. Copyright © 2017 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

Yinghao, Cui; He, Xue; Lingyan, Zhao

2017-12-01

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

Modeling the initiation of Primary Water Stress Corrosion Cracking in nickel base alloys 182 and 82 of Pressurized Water Reactors

International Nuclear Information System (INIS)

Wehbi, Mickael

2014-01-01

Nickel base welds are widely used to assemble components of the primary circuit of Pressurized Water Reactors (PWR) plants. International experience shows an increasing number of Stress Corrosion Cracks (SCC) in nickel base welds 182 and 82 which motivates the development of models predicting the time to SCC initiation for these materials. SCC involves several parameters such as materials, mechanics or environment interacting together. The goal of this study is to have a better understanding of the physical mechanisms occurring at grains boundaries involved in SCC. In-situ tensile test carried out on oxidized alloy 182 evidenced dispersion in the susceptibility to corrosion of grain boundaries. Moreover, the correlation between oxidation and cracking coupled with micro-mechanical simulations on synthetic polycrystalline aggregate, allowed to propose a cracking criterion of oxidized grain boundaries which is defined by both critical oxidation depth and local stress level. Due to the key role of intergranular oxidation in SCC and since significant dispersion is observed between grain boundaries, oxidation tests were performed on alloys 182 and 82 in order to model the intergranular oxidation kinetics as a function of chromium carbides precipitation, temperature and dissolved hydrogen content. The model allows statistical analyses and is embedded in a local initiation model. In this model, SCC initiation is defined by the cracking of the intergranular oxide and is followed by slow and fast crack growth until the crack depth reaches a given value. Simplifying assumptions were necessary to identify laws used in the SCC model. However, these laws will be useful to determine experimental conditions of future investigations carried out to improve the calibration used parameters. (author)

Irradiation assisted stress corrosion cracking of HTH Alloy X-750 and Alloy 625

International Nuclear Information System (INIS)

Mills, W.J.; Lebo, M.R.; Bajaj, R.; Kearns, J.J.; Hoffman, R.C.; Korinko, J.J.

1994-01-01

In-reactor testing of bolt-loaded precracked compact tension specimens was performed in 360 degree C water to determine effect of irradiation on the SCC behavior of HTH Alloy X-750 and direct aged Alloy 625. Out-of-flux and autoclave control specimens provided baseline data. Primary test variables were stress intensity factor, fluence, chemistry, processing history, prestrain. Results for the first series of experiments were presented at a previous conference. Data from two more recent experiments are compared with previous results; they confirm that high irradiation levels significantly reduce SCC resistance in HTH Alloy X-750. Heat-to-heat differences in IASCC were related to differences in boron content, with low boron heats showing improved SCC resistance. The in-reactor SCC performance of Alloy 625 was superior to that for Alloy X-750, as no cracking was observed in any Alloy 625 specimens even though they were tested at very high K 1 and fluence levels. A preliminary SCC usage model developed for Alloy X-750 indicates that in-reactor creep processes, which relax stresses but also increase crack tip strain rates, and radiolysis effects accelerate SCC. Hence, in-reactor SCC damage under high flux conditions may be more severe than that associated with postirradiation tests. In addition, preliminary mechanism studies were performed to determine the cause of IASCC In Alloy X-750

Fresh and mechanical properties of self compacting concrete containing copper slag as fine aggregates

Directory of Open Access Journals (Sweden)

Rahul Sharma

2017-03-01

Full Text Available An investigation is carried out on the development of Self Compacting Concrete (SCC using copper slag (CS as fine aggregates with partial and full replacement of sand. Six different SCC mixes (60% OPC and 40% Fly Ash with 0% as control mix, 20%, 40%, 60%, 80% and 100% of copper slag substituting sand with constant w/b ratio of 0.45 were cast and tested for fresh properties of SCC. Compressive strength and splitting tensile strength were evaluated at different ages and microstructural analysis was observed at 120 days. It has been observed that the fluidity of SCC mixes was significantly enhanced with the increment of copper slag. The test results showed that the compressive strength increases up to 60% copper slag as replacement of sand, beyond which decrease in strength was observed. The highest compressive strength was obtained at 20% copper slag substitution at different curing ages among all the mixes, except for 7 days curing. The splitting tensile strength of the CS substituted mixes in comparison to control concrete was found to increase at all the curing ages but the remarkable achievement of strength was detected at 60% copper slag replacement. The microscopic view from Scanning electron microscopy (SEM demonstrated more voids, capillary channels, and micro cracks with the increment of copper slag as substitution of sand as compared to the control mix.

Pull-Out Strength and Bond Behavior of Prestressing Strands in Prestressed Self-Consolidating Concrete.

Science.gov (United States)

Long, Wu-Jian; Khayat, Kamal Henri; Lemieux, Guillaume; Hwang, Soo-Duck; Xing, Feng

2014-10-10

With the extensive use of self-consolidating concrete (SCC) worldwide, it is important to ensure that such concrete can secure uniform in-situ mechanical properties that are similar to those obtained with properly consolidated concrete of conventional fluidity. Ensuring proper stability of SCC is essential to enhance the uniformity of in-situ mechanical properties, including bond to embedded reinforcement, which is critical for structural engineers considering the specification of SCC for prestressed applications. In this investigation, Six wall elements measuring 1540 mm × 2150 mm × 200 mm were cast using five SCC mixtures and one reference high-performance concrete (HPC) of normal consistency to evaluate the uniformity of bond strength between prestressing strands and concrete as well as the distribution of compressive strength obtained from cores along wall elements. The evaluated SCC mixtures used for casting wall elements were proportioned to achieve a slump flow consistency of 680 ± 15 mm and minimum caisson filling capacity of 80%, and visual stability index of 0.5 to 1. Given the spreads in viscosity and static stability of the SCC mixtures, the five wall elements exhibited different levels of homogeneity in in-situ compressive strength and pull-out bond strength. Test results also indicate that despite the high fluidity of SCC, stable concrete can lead to more homogenous in-situ properties than HPC of normal consistency subjected to mechanical vibration.

Effect of radiotherapy on serum SCC, CEA, CRFRA21-1, TAG72, CA199 and lymphocyte subsets in patients with esophageal squamous cell carcinoma

Directory of Open Access Journals (Sweden)

Sha Sha

2016-09-01

Full Text Available Objective: To study the effect of radiotherapy on serum SCC, CEA, CRFRA21-1, TAG72, CA199 and lymphocyte subsets in patients with esophageal squamous cell carcinoma. Methods: A total of 60 patients with esophageal squamous cell carcinoma in our hospital from January 2013 to January 2016 were selected as experiment group and 40 healthy subjects were selected as control group. Patients in experiment group were treated with 6MV X-ray radiation therapy. Serum SCC, CEA, CRFRA21-1, TAG72, CA199 and the cell percentage of peripheral blood CD4+, CD8+ were compared in control group and the experimental group before and after 1 month radiotherapy. Results: Before treatment, the levels of serum SCC, CEA and CRFRA21-1 in the experimental group were significantly higher than those in the control group (P0.05. Before treatment, the cell percentage of peripheral blood CD4+, CD8+ and the ratio of CD4+/CD8+ in experimental group was significantly lower than that of the control group, the percentage of peripheral blood CD8+ in the experimental group was significantly higher than that in the control group (P0.05, and in the experimental group, the proportion of CD4+ cells and the tatio of CD4+/CD8+ in peripheral blood was significantly lower than that of the control group, the proportion of CD8+ was significantly higher than that of the control group (P<0.05. Conclusions: Radiotherapy can significantly reduce the serum SCC, CEA, CRFRA21-1, TAG72 and CA199 levels of the patients with esophageal squamous cell carcinoma, but have less influence on the T lymphocyte subsets.

Studies on microstructure, mechanical and corrosion properties of high nitrogen stainless steel shielded metal arc welds

Science.gov (United States)

Mohammed, Raffi; Madhusudhan Reddy, G.; Srinivasa Rao, K.

2018-03-01

The present work is aimed at studying the microstructure, mechanical and corrosion properties of high nitrogen stainless steel shielded metal arc (SMA) welds made with Cromang-N electrode. Basis for selecting this electrode is to increase the solubility of nitrogen in weld metal due to high chromium and manganese content. Microstructures of the welds were characterized using optical microscopy (OM), field emission scanning electron microscopy (FESEM) and electron back scattered diffraction (EBSD) mainly to determine the morphology, phase analysis, grain size and orientation image mapping. Hardness, tensile and ductility bend tests were carried out to determine mechanical properties. Potentio-dynamic polarization testing was carried out to study the pitting corrosion resistance using a GillAC basic electrochemical system. Constant load type testing was carried out to study stress corrosion cracking (SCC) behaviour of welds. The investigation results shown that the selected Cr–Mn–N type electrode resulted in favourable microstructure and completely solidified as single phase coarse austenite. Mechanical properties of SMA welds are found to be inferior when compared to that of base metal and is due to coarse and dendritic structure.

Mechanical properties of self-compacted fiber concrete mixes

Directory of Open Access Journals (Sweden)

Mounir M. Kamal

2014-04-01

Full Text Available Increased productivity and improved working environment have had high priority in the development of concrete construction over the last decade. The major impact of the introduction of self-compacting concrete (SCC is connected to the production process. The productivity is drastically improved through the elimination of vibration compaction and process reorganization. The working environment is significantly enhanced through avoidance of vibration induced damages, reduced noise and improved safety. Additionally, SCC technology has improved the performance in terms of hardened concrete properties like surface quality, strength and durability. The main objective of this research was to determine the optimum content of fibers (steel and polypropylene fibers used in SCC. The effect of different fibers on the fresh and hardened properties was studied. An experimental investigation on the mechanical properties, including compressive strength, flexural strength and impact strength of fiber reinforced self-compacting concrete was performed. The results of the investigation showed that: the optimum dosage of steel and polypropylene fiber was 0.75% and 1.0% of the cement content, respectively. The impact performance was also improved due to the use of fibers. The control mix specimen failed suddenly in flexure and impact, the counterpart specimens contain fibers failed in a ductile manner, and failure was accompanied by several cracks.

Influence of calcined mud on the mechanical properties and shrinkage of self-compacting concrete

Directory of Open Access Journals (Sweden)

Fatima Taieb

2018-01-01

Full Text Available The use of SCC has a particular interest in terms of sustainable development. Indeed, their specific formulation leads to a greater volume of dough than for common concretes, thus, a larger quantity of cement. However, for economical, ecological and technical reasons, it is sought to limit their cement content [1]. It is therefore necessary to almost always use mineral additions as a partial replacement for cement because the technology of self-compacting concretes can consume large quantities of fines, in this case calcinated mud issued from dams dredging sediments that can give and/or ameliorate characteristics and performances of this type of concretes. Four SCCs had been formulated from the same composition where the only percentage of calcinated mud of Chorfa (west of Algeria dam changed (0%, 10%, 20% and 30%. The effect of calcinated mud on characteristics at fresh state of SCC according to AFGC was quantified. Mechanical strengths and shrinkage deformation (total, autogenous, drying were evaluated. The results show the possibility to make SCCs with different dosages of calcinated mud having strengths that can defy those of the control SCC. The analysis of free deformations indicates the beneficial impact of the mud by contributing to decrease the amplitudes of the shrinkage compared to those of the control SCC.

Dynamic thermo-chemo-mechanical strain of Zircaloy-4 slotted rings for evaluating strategies that mitigate stress corrosion cracking

Energy Technology Data Exchange (ETDEWEB)

Ferrier, G.A.; Metzler, J.; Farahani, M.; Chan, P.K.; Corcoran, E.C. [Royal Military College of Canada, Kingston, ON (Canada)

2014-07-01

Stress corrosion cracking (SCC) in Zircaloy-4 fuel sheaths has been investigated by static loading of slotted ring samples under hot and corrosive conditions. However, in nuclear reactors, power ramps can have short (e.g., 10-20 minutes) and recurring time frames due to dynamic processes such as on-power refuelling, adjuster rod manoeuvres, and load following. Therefore, to enable out-reactor dynamic testing, an apparatus was designed to dynamically strain slotted ring samples under SCC conditions. This apparatus can additionally be used to test fatigue properties. Unique capabilities of this apparatus and preliminary results obtained from static and dynamic tests are presented. (author)

Steam generator materials

International Nuclear Information System (INIS)

Kim, Joung Soo; Han, J. H.; Kim, H. P.; Lim, Y. S.; Lee, D. H.; Suh, J. H.; Hwang, S. S.; Hur, D. H.; Kim, D. J.; Kim, Y. H.

2002-05-01

In order to keep the nuclear power plant(NPP)s safe and increase their operating efficiency, axial stress corrosion cracking(SCC)(IGA/IGSCC, PWSCC, PbSCC) test techniques were developed and SCC property data of the archive steam generator tubing materials having been used in nuclear power plants operating in Korea were produced. The data obtained in this study were data-based, which will be used to clarify the damage mechanisms, to operate the plants safely, and to increase the lifetime of the tubing. In addition, the basic technologies for the improvement of the SCC property of the tubing materials, for new SCC inhibition, for damaged tube repair, and for manufacturing processes of the tubing were developed. In the 1 phase of this long term research, basic SCC test data obtained from the archive steam generator tubing materials used in NPPs operating in Korea were established. These basic technologies developed in the 1 phase will be used in developing process optimization during the 2 phase in order to develop application technologies to the field nuclear power plants

Measurements and mechanisms of localized aqueous corrosion in aluminum-lithium-copper alloys

Science.gov (United States)

Wall, Douglas; Stoner, Glenn E.

1991-01-01

Summary information is included for electrochemical aspects of stress corrosion cracking in alloy 2090 and an introduction to the work to be initiated on the new X2095 (Weldalite) alloy system. Stress corrosion cracking (SCC) was studied in both S-T and L-T orientations in alloy 2090. A constant load TTF test was performed in several environments with a potentiostatically applied potential. In the same environments the electrochemical behavior of phases found along subgrain boundaries was assessed. It was found that rapid failure due to SCC occurred when the following criteria was met: E(sub BR,T1) is less than E(sub applied) is less than E(sub Br, matrix phase). Although the L-T orientation is usually considered more resistant to SCC, failures in this orientation occurred when the stated criteria was met. This may be due to the relatively isotropic geometry of the subgrains which measure approximately 12 to 25 microns in diameters. Initial studies of alloy X2095 includes electrochemical characterization of three compositional variations each at three temperatures. The role of T(sub 1) dissolution in SCC behavior is addressed using techniques similar to those used in the research of 2090 described. SCC susceptibility is also studied using alternate immersion facilities at Reynolds Metals Corporation. Pitting is investigated in terms of stability, role of precipitate phases and constituent particles, and as initiation sites for SCC. In all research endeavors, attempts are made to link electrochemistry to microstructure. Previous work on 2090 provides a convenient basis for comparison since both alloys contain T(sub 1) precipitates but with different distributions. In 2090 T(sub 1) forms preferentially on subgrain boundaries whereas in X2095 the microstructure appears to be more homogeneous with finer T(sub 1) particles. Another point for comparison is the delta prime strengthening phase found in 2090 but absent in X2095.

Inkjet Printed Fully-Passive Body-Worn Wireless Sensors for Smart and Connected Community (SCC

Directory of Open Access Journals (Sweden)

Bashir I. Morshed

2017-11-01

Full Text Available Future Smart and Connected Communities (SCC will utilize distributed sensors and embedded computing to seamlessly generate meaningful data that can assist individuals, communities, and society with interlocking physical, social, behavioral, economic, and infrastructural interaction. SCC will require newer technologies for seamless and unobtrusive sensing and computation in natural settings. This work presents a new technology for health monitoring with low-cost body-worn disposable fully passive electronic sensors, along with a scanner, smartphone app, and web-server for a complete smart sensor system framework. The novel wireless resistive analog passive (WRAP sensors are printed using an inkjet printing (IJP technique on paper with silver inks (Novacentrix Ag B40, sheet resistance of 21 mΩ/sq and incorporate a few discrete surface mounted electronic components (overall thickness of <1 mm. These zero-power flexible sensors are powered through a wireless inductive link from a low-power scanner (500 mW during scanning burst of 100 ms by amplitude modulation at the carrier signal of 13.56 MHz. While development of various WRAP sensors is ongoing, this paper describes development of a WRAP temperature sensor in detail as an illustration. The prototypes were functionally verified at various temperatures with energy consumption of as low as 50 mJ per scan. The data is analyzed with a smartphone app that computes severity (Events-of-Interest, or EoI using a real-time algorithm. The severity can then be anonymously shared with a custom web-server, and visualized either in temporal or spatial domains. This research aims to reduce ER visits of patients by enabling self-monitoring, thereby improving community health for SSC.

Influence of alkali metal oxides and alkaline earth metal oxides on the mitigation of stress corrosion cracking in CANDU fuel sheathing

Energy Technology Data Exchange (ETDEWEB)

Metzler, J.; Ferrier, G.A.; Farahani, M.; Chan, P.K.; Corcoran, E.C., E-mail: Joseph.Metzler@rmc.ca [Royal Military College of Canada, Kingston, ON (Canada)

2015-07-01

Stress corrosion cracking (SCC)can cause failures of CANDU Zircaloy-4 fuel sheathing. The process occurs when a corrosive element (i.e.,iodine) interacts with a susceptible material that is under sufficient strain at a high temperature. Currently, there is an ongoing effort to improve SCC mitigation strategies for future iterations of CANDU reactors. A potential mechanism for SCC mitigation involves utilizing alkali metal oxides and alkaline earth metal oxides that will sequester corrosive iodine while actively repairing a protective oxide layer on the sheath. SCC tests performed with sodium oxide (Na{sub 2}O) and calcium oxide (CaO) have shown to decrease significantly the sheath degradation. (author)

Pull-Out Strength and Bond Behavior of Prestressing Strands in Prestressed Self-Consolidating Concrete

Directory of Open Access Journals (Sweden)

Wu-Jian Long

2014-10-01

Full Text Available With the extensive use of self-consolidating concrete (SCC worldwide, it is important to ensure that such concrete can secure uniform in-situ mechanical properties that are similar to those obtained with properly consolidated concrete of conventional fluidity. Ensuring proper stability of SCC is essential to enhance the uniformity of in-situ mechanical properties, including bond to embedded reinforcement, which is critical for structural engineers considering the specification of SCC for prestressed applications. In this investigation, Six wall elements measuring 1540 mm × 2150 mm × 200 mm were cast using five SCC mixtures and one reference high-performance concrete (HPC of normal consistency to evaluate the uniformity of bond strength between prestressing strands and concrete as well as the distribution of compressive strength obtained from cores along wall elements. The evaluated SCC mixtures used for casting wall elements were proportioned to achieve a slump flow consistency of 680 ± 15 mm and minimum caisson filling capacity of 80%, and visual stability index of 0.5 to 1. Given the spreads in viscosity and static stability of the SCC mixtures, the five wall elements exhibited different levels of homogeneity in in-situ compressive strength and pull-out bond strength. Test results also indicate that despite the high fluidity of SCC, stable concrete can lead to more homogenous in-situ properties than HPC of normal consistency subjected to mechanical vibration.

Experimental investigations into the shear behavior of self-compacting RC beams with and without shear reinforcement

Directory of Open Access Journals (Sweden)

Ammar N. HANOON

2014-12-01

Full Text Available Self-compacting concrete (SCC is a new generation of high-performance concrete, known for its excellent deformability and high resistance to segregation and bleeding. Nonetheless, SCC may be incapable of resisting shear because the shear resistance mechanisms of this concrete are uncertain, especially the aggregate interlock mechanism. This uncertainty is attributed to the fact that SCC contains a smaller amount of coarse aggregates than normal concrete (NC does. This study focuses on the shear strength of self-compacting reinforced concrete (RC beams with and without shear reinforcement. A total of 16 RC beam specimens was manufactured and tested in terms of shear span-to-depth ratio and flexural and shear reinforcement ratio. The test results were compared with those of the shear design equations developed by ACI, BS, CAN and NZ codes. Results show that an increase in web reinforcement enhanced cracking strength and ultimate load. Shear-tension failure was the control failure in all tested beams.

Observations and insights into Pb-assisted stress corrosion cracking of alloy 600 steam generator tubes

International Nuclear Information System (INIS)

Thomas, L.; Bruemmer, Stephen M.

2005-01-01

Pb-assisted stress-corrosion cracking (PbSCC) of Alloy 600 steam-generator tubing in high-temperature-water service and laboratory tests were studied by analytical transmission electron microscopy of cross-sectioned samples. Examinations of pulled tubes from many pressurized water reactors revealed lead in cracks from 11 of 17 samples. Comparisons of the degraded intergranular structures with ones produced in simple laboratory tests with PbO in near-neutral AVT water showed that the PbSCC characteristics in service tubing could be reproduced without complex chemistries and heat-flow conditions that can occur during plant operation. Observations of intergranular and transgranular cracks promoted by Pb in the test samples also provided new insights into the mechanisms of PbSCC in mill-annealed and thermally treated Alloy 600

Gonadal development and growth in 46,XX and 46,XY individuals with P450scc deficiency (congenital lipoid adrenal hyperplasia)

DEFF Research Database (Denmark)

Müller, J; Torsson, A; Damkjaer Nielsen, M

1991-01-01

We have investigated gonadal development and growth in 4 individuals (3 with 46,XY and 1 with 46,XX karyotype) with P450scc deficiency. One patient died at 2 months of age from adrenal insufficiency, while the remaining 3 individuals were healthy and developed normally (age at follow-up: 18, 10...... and 8 years). In the surviving individuals, the diagnosis was established during the first 2-4 months of life by extensive endocrine studies of blood and urine. In the remaining patient, the diagnosis was made on the basis of karyotype (46,XY), anatomy of internal and external genitalia and adrenal...... pathology. Gonadectomy was performed in the 2 surviving 46,XY individuals at the age of 7 years, and histological examination showed normal testicular morphology but very few germ cells. Postmortem examination of the testes of the 2-month-old subject showed normal testicular histology, and quantitative...

European Union bulk tank SCC standards and proposed US standards: Compliance based on data from four Federal Milk Marketing Orders

Science.gov (United States)

The objective of this study was to evaluate compliance of US producers with the proposed BTSCC limits. Four different SCC levels of compliance were evaluated: 750K; 600K; 500K; 400K. For the 12 month period ending October 2010, 1.0% of producers and 0.2% of milk exceeded the current US limit of 750K...

Biaxial mechanical tests in zircaloy-4

International Nuclear Information System (INIS)

Mintzer, S.R.; Bordoni, R.A.A.; Falcone, J.M.

1980-01-01

The texture of the zircaloy-4 tubes used as cladding in nuclear fuel elements determines anisotropy of the mechanical properties. As a consequence, the uniaxial tests to determine the mechanical behaviour of the tubes are incomplete. Furthermore, the cladding in use is subject to creep with a state of biaxial tensions. For this reason it is also important to determine the biaxial mechanical properties. The creep tests were performed by internal pressure for a state of axial to circumferential tensions of 0.5. Among the experimental procedures are described: preparation of the test specimens, pressurizing equipment, and the implementation of a device that permits a permanent register of the deformation. For the non-irradiated Atucha type zircaloy-4 sheaths, experimental curves of circumferential deformation versus time were obtained, in tests at constant pressure and for different values of temperature and pressure. An empirical function was determined to adjust the experimental values for the speed of the circumferential deformation in terms of the initial tension applied, temperature and deformation, and the change of the corresponding parameters in accordance to the range of the tensions. Also the activation energy for creep was determined. (M.E.L.) [es

Polarization tests of one-particle-exchange mechanisms

International Nuclear Information System (INIS)

Goldstein, G.R.; Moravcsik, M.J.

1984-01-01

Since one-particle-exchange (OPE) mechanisms are predominant in all aspects of elementary-particle dynamics, a novel class of polarization tests is proposed for such mechanisms. They test whether a single particle of total angular momentum J is exchanged (''J constraints'') and whether the process can be factorized into two vertices (''factorization constraints''), but the tests are independent of more detailed dynamical features such as the exact nature of the coupling at the vertices. Except for a restricted type of processes containing some low spin values, the constraints reduce the number of reaction amplitudes and offer tests of OPE which are independent of the value of J. The tests have a particularly simple form in a ''magic'' formalism in which the quantization directions of the particles are in the reaction plane and are rotated from the helicity directions by a ''magic'' angle which can be easily specified for a given s and t. The tests consist of measuring whether a certain polarization quantity vanishes or not, thus providing sensitive ''null experiments'' for the exploration of particle dynamics. The results are illustrated on the popular reaction (1/2)+(1/2)→(1/2)+(1/2), which is embodied, for example, in elastic nucleon-nucleon scattering. The tests can be used either for one single-exchange mechanism or for a combination of such mechanisms (even if they involve different J exchanges), as long as they all have the same type of parity

The effect of a single tensile overload on stress corrosion cracking growth of stainless steel in a light water reactor environment

International Nuclear Information System (INIS)

Xue He; Li Zhijun; Lu Zhanpeng; Shoji, Tetsuo

2011-01-01

Research highlights: → The affect of a single tensile overload on SCC growth rate is investigated. → A single tensile overload would produce a residual plastic strain in the SCC tip. → The residual plastic strain would decrease the plastic strain rate in the SCC tip. → A single tensile overload would cause crack growth rate retardation in the SCC tip. → SCC growth rate in the quasi-stationary crack tip is relatively lower. - Abstract: It has been found that a single tensile overload applied during constant load amplitude might cause crack growth rate retardation in various crack propagating experiments which include fatigue test and stress corrosion cracking (SCC) test. To understand the affecting mechanism of a single tensile overload on SCC growth rate of stainless steel or nickel base alloy in light water reactor environment, based on elastic-plastic finite element method (EPFEM), the residual plastic strain in both tips of stationary and growing crack of contoured double cantilever beam (CDCB) specimen was simulated and analyzed in this study. The results of this investigation demonstrate that a residual plastic strain in the region immediately ahead of the crack tips will be produced when a single tensile overload is applied, and the residual plastic strain will decrease the plastic strain rate level in the growing crack tip, which will causes crack growth rate retardation in the tip of SCC.

Improved Stress Corrosion Cracking Resistance and Strength of a Two-Step Aged Al-Zn-Mg-Cu Alloy Using Taguchi Method

Science.gov (United States)

Lin, Lianghua; Liu, Zhiyi; Ying, Puyou; Liu, Meng

2015-12-01

Multi-step heat treatment effectively enhances the stress corrosion cracking (SCC) resistance but usually degrades the mechanical properties of Al-Zn-Mg-Cu alloys. With the aim to enhance SCC resistance as well as strength of Al-Zn-Mg-Cu alloys, we have optimized the process parameters during two-step aging of Al-6.1Zn-2.8Mg-1.9Cu alloy by Taguchi's L9 orthogonal array. In this work, analysis of variance (ANOVA) was performed to find out the significant heat treatment parameters. The slow strain rate testing combined with scanning electron microscope and transmission electron microscope was employed to study the SCC behaviors of Al-Zn-Mg-Cu alloy. Results showed that the contour map produced by ANOVA offered a reliable reference for selection of optimum heat treatment parameters. By using this method, a desired combination of mechanical performances and SCC resistance was obtained.

Relationship between stress corrosion cracking and low frequency fatigue-corrosion of alloy 600 in PWR primary water

International Nuclear Information System (INIS)

Bosch, C.

1998-01-01

Stress corrosion cracking of PWR vessel head adapters is a main problem for nuclear industry. With the aim to better understand the influence of the mechanical parameters on the cracking phenomena (by stress corrosion (SCC) or fatigue corrosion (FC)) of alloy 600 exposed to primary PWR coolant, a parametrical study has been carried out. Crack propagation tests on CT test specimens have been implemented under static loads (stress corrosion tests) or low frequency cyclic loads (fatigue corrosion tests). Results (frequency influence, type of cycles, ratio charge on velocities and propagation modes of cracks) have allowed to characterize the transition domain between the crack phenomena of SCC and FC. With the obtained results, it has been possible too to differentiate the effects due to environmental factors and the effects due to mechanical factors. At last, a quantitative fractographic study and the observations of the microstructure at the tip of crack have led to a better understanding of the transitions of the crack propagation mode between the SCC and the FC. (O.M.)

Effect and mechanism of cadmium on the progesterone synthesis of ovaries

International Nuclear Information System (INIS)

Zhang Wenchang; Jia Haimei

2007-01-01

The paper presents results of the effect of cadmium on the progesterone synthesis of ovaries. In the current study, we investigated whether Cd also disrupts progesterone synthesis via steroidogenic acute regulatory protein (StAR) and P450 cholesterol side-chain cleavage (P450scc), which play important roles in progesterone synthesis. The Wistar rats were exposed to cadmium in vivo (at 2.5, 5, 7.5 mg/kg, as a single s.c. dose). We showed that the serum P 4 and granule cells P 4 of rats were significantly lower than control group. Ovaries granule cells were incubated in Dulbecco-modified Eagle medium +15% fetal bovine serum with 0, 10, 20, or 40 μM CdCl 2 in vitro, progesterone levels were declined in a dose-dependent manner. Our data showed that the expression of StAR and P450scc in vivo or in vitro were inhibited when treated with CdCl 2 (p 2 treatment; the expression of StAR mRNA and P450scc mRNA in 8-Br-cAMP + 40 μM CdCl 2 were significantly higher than 40 μM CdCl 2 , and were lower than control group. We concluded that StAR, which delivers cholesterol to the inner mitochondrial membrane, is one site at which Cd interferes with progesterone production in cultured rats ovarian granule cells; P450scc, which conveys cholesterol to pregnenolone, is anther site. The mechanisms were mainly controlled by the cAMP-dependent pathway

Dedicated Beamline Facilities for Catalytic Research. Synchrotron Catalysis Consortium (SCC)

Energy Technology Data Exchange (ETDEWEB)

Chen, Jingguang [Columbia Univ., New York, NY; Frenkel, Anatoly [Yeshiva Univ., New York, NY (United States); Rodriguez, Jose [Brookhaven National Lab. (BNL), Upton, NY (United States); Adzic, Radoslav [Brookhaven National Lab. (BNL), Upton, NY (United States); Bare, Simon R. [UOP LLC, Des Plaines, IL (United States); Hulbert, Steve L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Karim, Ayman [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mullins, David R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Overbury, Steve [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-03-04

Synchrotron spectroscopies offer unique advantages over conventional techniques, including higher detection sensitivity and molecular specificity, faster detection rate, and more in-depth information regarding the structural, electronic and catalytic properties under in-situ reaction conditions. Despite these advantages, synchrotron techniques are often underutilized or unexplored by the catalysis community due to various perceived and real barriers, which will be addressed in the current proposal. Since its establishment in 2005, the Synchrotron Catalysis Consortium (SCC) has coordinated significant efforts to promote the utilization of cutting-edge catalytic research under in-situ conditions. The purpose of the current renewal proposal is aimed to provide assistance, and to develop new sciences/techniques, for the catalysis community through the following concerted efforts: Coordinating the implementation of a suite of beamlines for catalysis studies at the new NSLS-II synchrotron source; Providing assistance and coordination for catalysis users at an SSRL catalysis beamline during the initial period of NSLS to NSLS II transition; Designing in-situ reactors for a variety of catalytic and electrocatalytic studies; Assisting experimental set-up and data analysis by a dedicated research scientist; Offering training courses and help sessions by the PIs and co-PIs.

Demonstration through EPR tests of the sensitivity of austeno-ferritic steels to intergranular corrosion and stress corrosion cracking

International Nuclear Information System (INIS)

Lopez, Nathalie

1997-01-01

Duplex stainless steels can be sensitised to intergranular corrosion and stress corrosion cracking (SCC) under some conditions (heat treatments, welding). The aim of this work is to contribute to the validation of the EPR (Electrochemical Potentiodynamic Reactivation) test in order to determine conditions for normalisation. This method, based on the dissolution of chromium depleted areas due to precipitation of σ-phase, provides a degree of sensitisation to intergranular corrosion. The test is broaden considering the mechanical stress by the way of slow strain rate tests, performed in chloride magnesium and in a solution similar to the EPR solution. A metallurgical study puts on the precipitates and the structural modifications due to welding and heat treatments, in order to make a critical analysis of the EPR test. (author) [fr

Evaluation of a 3% surf solution (surf field mastitis test) for the diagnosis of subclinical bovine and bubaline mastitis.

Science.gov (United States)

Muhammad, Ghulam; Naureen, Abeera; Asi, Muhammad Nadeem; Saqib, Muhammad; Fazal-ur-Rehman

2010-03-01

To evaluate a 3% solution of household detergent viz., Surf Excel (Surf field mastitis test, SFMT) vis-à-vis California mastitis test (CMT), Whiteside test (WST), somatic cell counts (SCC; cut off limit = 5 x 10(5) cells per millilitre) and bacteriological cultures for the detection of subclinical mastitis in quarter foremilk samples (n=800) of dairy cows and buffaloes. Culture and SCC were used as gold standards. All tests were evaluated parallel and serial patterns. The sensitivities of SFMT, SCC, culture, CMT and WST in parallel testing were 72.82, 81.55, 87.38, 75.73 and 54.37%, respectively in cows, while 66.22, 79.73, 82.43, 70.27 and 50.00, respectively in buffaloes. SFMT was significantly (pnegative predictive values of SFMT (93.50 in cow; 96.35 in buffaloes) differed non-significantly from that of CMT (94.02 in cow; 96.15 in buffaloes). The kappa index between the tests was moderate to perfect both in parallel (0.54 to >0.80) and serial (0.58 to >0.8) testing. On the basis of closely similar diagnostic efficiency of SFMT to CMT in terms of sensitivity, specificity, predictive values and kappa index together with inexpensive and ready availability of SFMT reagent, it tempting to suggest that SFMT can be use as a cheaper, user-friendly alternative animal-side subclinical mastitis diagnostic test in poor countries.

Numerical study on dissimilar guide vane design with SCC piston for air and emulsified biofuel mixing improvement

Directory of Open Access Journals (Sweden)

Hamid Mohd Fadzli

2017-01-01

Full Text Available Crude palm oil (CPO is one of the most potential biofuels that can be applied in the conventional diesel engines, where the chemical properties of CPO are comparable to diesel fuel. However, its higher viscosity and heavier molecules can contributes to several engine problems such as low atomization during injection, carbon deposit formation, injector clogging, low mixing with air and lower combustion efficiency. An emulsification of biofuel and modifications of few engine critical components have been identified to mitigate the issues. This paper presents the effects of dissimilar guide vane design (GVD in terms of height variation of 0.25R, 0.3R and 0.35R at the intake manifold with shallow depth re-entrance combustion chamber (SCC piston application to the incylinder air flow characteristics improvement. The simulation results show that the intake manifold with GVD improved the performance of the air flow characteristic particularly swirl, tumble and cross tumble ratios from the intake manifold to the engine. The GVD with the height of 0.3R was found to be the optimum design with respect to the overall improvement of the air flow characteristic. The improvement of the air flow characteristic with the application of GVD and SCC piston in the engine was expected to contribute to a better air fuel mixing, fuel atomization and combustion efficiency of the engine using emulsified biofuel as a source of fuel.

Self-consolidating concretes containing waste PET bottles as sand replacement

Science.gov (United States)

Khalid, Faisal Sheikh; Azmi, Nurul Bazilah; Mazenan, Puteri Natasya; Shahidan, Shahiron; Othman, Nor hazurina; Guntor, Nickholas Anting Anak

2018-02-01

This study evaluates the effect of self-consolidating concrete (SCC) containing waste polyethylene terephthalate (PET) granules on the fresh, mechanical and water absorption properties. Fine aggregates were replaced from 0% to 8% by PET granules. The fresh properties of SCC containing PET granules were determined using slump flow and V-funnel flow time tests. The compressive and splitting tensile strength were evaluated. The results indicated that utilization of waste PET granules in production of SCC could be an effective way for recycling purpose. The maximum amount of PET replacement should be limited to 5%. Exceeding 5% of PET content may result in an increase of V-funnel flow time to overpass the limiting value, decrease in strength. The production of high performance SCC containing 5% PET granules satisfies all the requirements for SCC with satisfactory outputs.

Constant strain rate test and SCC-behaviour of stainless steels

International Nuclear Information System (INIS)

Krauss, H.; Speckhardt, H.

1979-01-01

In the present work, the stress corrosion cracking behaviour in boiling aqueous 35% magnesium chloride solution under conditions of no external current was investigated as a function of the defined extension rates for the two austenitic steels X 2 CrNi 189 and X 2 CrNiSi 1815, as well as for both ferritic austenitic steels X 6 CrNiMoCu 217 and X 2 CrNiMoN 225. The endurance time found until cracking, the maximum tensile stress, the sample stretching up to cracking and the relative rupture energy were determined for the evaluation, as well as metallographic investigations to describe the crack picture, test surface appearance and attack picture carried out. (orig.) 891 RW/orig. 892 BRE [de

On the mechanism of polypropylene fibres in preventing fire spalling in self-compacting and high-performance cement paste

International Nuclear Information System (INIS)

Liu, X.; Ye, G.; De Schutter, G.; Yuan, Y.; Taerwe, L.

2008-01-01

With the increasing application of self-compacting concrete (SCC) in construction and infrastructure, the fire spalling behavior of SCC has been attracting due attention. In high performance concrete (HPC), addition of polypropylene fibers (PP fibers) is widely used as an effective method to prevent explosive spalling. Hence, it would be useful to investigate whether the PP fibers are also efficient in SCC to avoid explosive spalling. However, no universal agreement exists concerning the fundamental mechanism of reducing the spalling risk by adding PP fiber. For SCC, the reduction of flowability should be considered when adding a significant amount of fibres. In this investigation, both the micro-level and macro-level properties of pastes with different fiber contents were studied in order to investigate the role of PP fiber at elevated temperature in self-compacting cement paste samples. The micro properties were studied by backscattering electron microscopy (BSE) and mercury intrusion porosimetry (MIP) tests. The modification of the pore structure at elevated temperature was investigated as well as the morphology of the PP fibers. Some macro properties were measured, such as the gas permeability of self-compacting cement paste after heating at different temperatures. The factors influencing gas permeability were analyzed. It is shown that with the melting of PP fiber, no significant increase in total pore volume is obtained. However, the connectivity of isolated pores increases, leading to an increase of gas permeability. With the increase of temperature, the addition of PP fibers reduces the damage of cement pastes, as seen from the total pore volume and the threshold pore diameter changes. From this investigation, it is concluded that the connectivity of pores as well as the creation of micro cracks are the major factors which determine the gas permeability after exposure to high temperatures. Furthermore, the connectivity of the pores acts as a dominant factor

An Investigation into Stress Corrosion Cracking of Dissimilar Metal Welds with 304L Stainless Steel and Alloy 82 in High Temperature Pure Water

Science.gov (United States)

Yeh, Tsung-Kuang; Huang, Guan-Ru; Tsai, Chuen-Horng; Wang, Mei-Ya

For a better understanding toward stress corrosion cracking (SCC) in dissimilar metal welds with 304L stainless steel and Alloy 82, the SCC growth behavior in the transition regions of weld joints was investigated via slow strain rate tensile (SSRT) tests in 280 oC pure water with a dissolve oxygen level of 300 ppb. Prior to the SSRT tests, samples with dissimilar metal welds were prepared and underwent various pretreatments, including post-weld heat treatment (PWHT), shot peening, solution annealing, and mechanical grinding. In addition to the SSRT tests, measurements of degree of sensitization and micro-hardness on the transition regions of the metal welds were also conducted. According to the test results, the samples having undergone PWHTs exhibited relatively high degrees of sensitization. Distinct decreases in hardness were observed in the heat-affected zones of the base metals in all samples. Furthermore, the fracture planes of all samples after the SSRT tests were located at the stainless steel sides and were in parallel with the fusion lines. Among the treating conditions investigated in this study, a PWHT would pose a detrimental effect on the samples in the aspects of mechanical property and degree of SCC. Solution annealing would lead to the greatest improvement in ductility and SCC retardation, and shot peening would provide the treated samples with a positive improvement in ductility and corrosion retardation, but not to a great extent.

Nuclear power plant life extension and management aspects; neutron irradiation embrittlement and stress corrosion cracking - two possible degradation mechanisms and methods for their mitigation

International Nuclear Information System (INIS)

Tipping, P.; Ineichen, U.; Cripps, R.C.

1994-01-01

The response of a mock-up low alloy ferritic reactor pressure vessel (RPV) steel and associated weldments to neutron irradiation has been studied using a combination of hardness, tensile, fracture mechanical and toughness tests in combination with annealing treatments. Thermal analysis using isochronal and isothermal techniques has indicated that annealing at a minimum of 440 o C for 168h is needed to mitigate neutron embrittlement received at 290 o C. Rates of re-embrittlement after annealing and reirradiating are no faster than initial rates, even up to neutron fluences as high as 5x10 19 cm -2 (energy E>1 MeV). All mechanical properties measured benefited from annealing. Thus, annealing is indicated as one measure for maintaining mechanical properties in irradiated low alloy steels and welds and should be considered in plant life management strategies. The influence of simulated reactor coolant water chemistry on the stress corrosion cracking propensity of ferritic low alloy steel specimens in autoclave loop experiments has also been studied. The double cantilever bend specimens were fatigue pre-cracked and wedge-loaded to different degrees to induce nominal stress intensity factors between 15-95 MPa.m 1/2 . Other specimens were subjected to stress using a tensile loading device integral with the test autoclave. The importance of close control of the dissolved oxygen content and the conductivity of the water has become evident under these experimental conditions. The RPV material and degree and mode of loading are also important parameters in SCC studies; stress intensity factors above 30 MPa.m 1/2 have been associated with SCC in these studies. (author) 2 figs., 13 refs

Verification testing of the compression performance of the HEVC screen content coding extensions

Science.gov (United States)

Sullivan, Gary J.; Baroncini, Vittorio A.; Yu, Haoping; Joshi, Rajan L.; Liu, Shan; Xiu, Xiaoyu; Xu, Jizheng

2017-09-01

This paper reports on verification testing of the coding performance of the screen content coding (SCC) extensions of the High Efficiency Video Coding (HEVC) standard (Rec. ITU-T H.265 | ISO/IEC 23008-2 MPEG-H Part 2). The coding performance of HEVC screen content model (SCM) reference software is compared with that of the HEVC test model (HM) without the SCC extensions, as well as with the Advanced Video Coding (AVC) joint model (JM) reference software, for both lossy and mathematically lossless compression using All-Intra (AI), Random Access (RA), and Lowdelay B (LB) encoding structures and using similar encoding techniques. Video test sequences in 1920×1080 RGB 4:4:4, YCbCr 4:4:4, and YCbCr 4:2:0 colour sampling formats with 8 bits per sample are tested in two categories: "text and graphics with motion" (TGM) and "mixed" content. For lossless coding, the encodings are evaluated in terms of relative bit-rate savings. For lossy compression, subjective testing was conducted at 4 quality levels for each coding case, and the test results are presented through mean opinion score (MOS) curves. The relative coding performance is also evaluated in terms of Bjøntegaard-delta (BD) bit-rate savings for equal PSNR quality. The perceptual tests and objective metric measurements show a very substantial benefit in coding efficiency for the SCC extensions, and provided consistent results with a high degree of confidence. For TGM video, the estimated bit-rate savings ranged from 60-90% relative to the JM and 40-80% relative to the HM, depending on the AI/RA/LB configuration category and colour sampling format.

SCC and Corrosion Fatigue characterization of a Ti-6Al-4V alloy in a corrosive environment – experiments and numerical models

Directory of Open Access Journals (Sweden)

S. Baragetti

2014-10-01

Full Text Available In the present article, a review of the complete characterization in different aggressive media of a Ti-6Al-4V titanium alloy, performed by the Structural Mechanics Laboratory of the University of Bergamo, is presented. The light alloy has been investigated in terms of corrosion fatigue, by axial fatigue testing (R = 0.1 of smooth and notched flat dogbone specimens in laboratory air, 3.5% wt. NaCl–water mixture and methanol–water mixture at different concentrations. The first corrosive medium reproduced a marine environment, while the latter was used as a reference aggressive environment. Results showed that a certain corrosion fatigue resistance is found in a salt water medium, while the methanol environment caused a significant drop – from 23% to 55% in terms of limiting stress reduction – of the fatigue resistance of the Ti-6Al-4V alloy, even for a solution containing 5% of methanol. A Stress Corrosion Cracking (SCC experimental campaign at different methanol concentrations has been conducted over slightly notched dog-bone specimens (Kt = 1.18, to characterize the corrosion resistance of the alloy under quasi-static load conditions. Finally, crack propagation models have been implemented to predict the crack propagation rates for smooth specimens, by using Paris, Walker and Kato-Deng-Inoue-Takatsu propagation formulae. The different outcomes from the forecasting numerical models were compared with experimental results, proposing modeling procedures for the numerical simulation of fatigue behavior of a Ti-6Al-4V alloy.

Stress corrosion cracking of X80 pipeline steel exposed to high pH solutions with different concentrations of bicarbonate

Science.gov (United States)

Fan, Lin; Du, Cui-wei; Liu, Zhi-yong; Li, Xiao-gang

2013-07-01

Susceptibilities to stress corrosion cracking (SCC) of X80 pipeline steel in high pH solutions with various concentrations of HCO{3/-} at a passive potential of -0.2 V vs. SCE were investigated by slow strain rate tensile (SSRT) test. The SCC mechanism and the effect of HCO{3/-} were discussed with the aid of electrochemical techniques. It is indicated that X80 steel shows enhanced susceptibility to SCC with the concentration of HCO{3/-} increasing from 0.15 to 1.00 mol/L, and the susceptibility can be evaluated in terms of current density at -0.2 V vs. SCE. The SCC behavior is controlled by the dissolution-based mechanism in these circumstances. Increasing the concentration of HCO{3/-} not only increases the risk of rupture of passive films but also promotes the anodic dissolution of crack tips. Besides, little susceptibility to SCC is found in dilute solution containing 0.05 mol/L HCO{3/-} for X80 steel. This can be attributed to the inhibited repassivation of passive films, manifesting as a more intensive dissolution in the non-crack tip areas than at the crack tips.

The effect of tempering on mechanical properties of 50Mn18Cr4WN retaining ring material

International Nuclear Information System (INIS)

Sun, M.C.; Guo, C.H.; Zheng, Z.Z.; Ma, Z.M.

1990-01-01

50Mn18Cr4WN is a retaining ring steel. It is strengthened by solution heat treatment and cold working. The process produces high macro residual stress. The retaining ring must be tempered for stress-relief. When the ring is sleeved, it is heated too. If the retaining ring is tempered, are the mechanical properties of the retaining ring damaged? The problem is described in the article. The tempering of testing pieces was carried out at several temperatures: 350degC, 400degC, 450degC, 500degC and 650degC. The tempering time was 3h. The yield point, tensile strength, elongation and reduction of area were determined by means of the tensile test. In the results, for temperatures between 350degC and 450degC, the yield point, tensile strength, elongation and reduction of area did not change notably. A stress corrosion cracking test was also carried out in a 3%Ni 4 NO 3 , 36%Ca(NO 3 ) 2 aqueous solution. K 1scc values after tempering at 450degC and without tempering were measured. The results showed that the K 1scc after tempering at 450degC decreased notably. Micrographs show that carbo-nitride precipitated. The precipitated carbo-nitride particles increased in size at the grain boundaries. The precipitated carbonitride particles increased in number at slip lines. It is clear that the precipitated particles lead to the increase of micro-cells and the micro-cells aggravated the stress corrosion cracking process. (orig.)

The role of anodic dissolution in the stress corrosion cracking of Al-Li-Cu alloy 2090

International Nuclear Information System (INIS)

Buchheit, R.G. Jr.; Wall, F.D.; Stoner, G.E.; Moran, J.P.

1991-01-01

The short-transverse (S-T) stress corrosion cracking (SCC) behavior of Al-Li-CU alloy 2090 was studied using a static load SCC test technique. Time to failure was measured as a function of applied potential in several different environments. Rapid SCC failures ( br, T1 applied br, matrix where potentials refer to the breakaway potentials of the subgrain boundary T 1 (Al 2 CuLi) phase and the α-Al matrix phase. E br values were measured using potentiodynamic polarization of bulk materials intended to simulate the individual phases found in the subgrain boundary region. Results strongly suggest an anodic dissolution based SCC mechanism for this alloy where selective dissolution of T 1 on the subgrain boundary is a critical step. The unusual pre-exposure embrittlement phenomenon demonstrated by Al- Li alloys is also shown to be consistent with these simple SCC criteria. 21 refs., 9 figs., 6 tabs

Prediction of PWSCC in nickel base alloys using crack growth rate models

International Nuclear Information System (INIS)

Thompson, C.D.

1995-01-01

The Ford/Andresen slip dissolution SCC model, originally developed for stainless steel components in BWR environments, has been applied to Alloy 600 and Alloy X-750 tested in deaerated pure water chemistry. A method is described whereby the crack growth rates measured in compact tension specimens can be used to estimate crack growth in a component. Good agreement was found between model prediction and measured SCC in X-750 threaded fasteners over a wide range of temperatures, stresses, and material condition. Most data support the basic assumption of this model that cracks initiate early in life. The evidence supporting a particular SCC mechanism is mixed. Electrochemical repassivation data and estimates of oxide fracture strain indicate that the slip dissolution model can account for the observed crack growth rates, provided primary rather than secondary creep rates are used. However, approximately 100 cross-sectional TEM foils of SCC cracks including crack tips reveal no evidence of enhanced plasticity or unique dislocation patterns at the crack tip or along the crack to support a classic slip dissolution mechanism. No voids, hydrides,, or microcracks are found in the vicinity of the crack tips creating doubt about classic hydrogen related mechanisms. The bulk oxide films exhibit a surface oxide which is often different than the oxide found within a crack. Although bulk chromium concentration affects the rate of SCC, analytical data indicates the mechanism does not result from chromium depletion at the grain boundaries. The overall findings support a corrosion/dissolution mechanism but not one necessarily related to slip at the crack tip. (author). 12 refs, 27 figs

Prediction of pure water stress corrosion cracking (PWSCC) in nickel base alloys using crack growth rate models

International Nuclear Information System (INIS)

Thompson, C.D.; Krasodomski, H.T.; Lewis, N.; Makar, G.L.

1995-01-01

The Ford/Andresen slip dissolution SCC model, originally developed for stainless steel components in BWR environments, has been applied to Alloy 600 and Alloy X-750 tested in deaerated pure water chemistry. A method is described whereby the crack growth rates measured in compact tension specimens can be used to estimate crack growth in a component. Good agreement was found between model prediction and measured SCC in X-750 threaded fasteners over a wide range of temperatures, stresses, and material condition. Most data support the basic assumption of this model that cracks initiate early in life. The evidence supporting a particular SCC mechanism is mixed. Electrochemical repassivation data and estimates of oxide fracture strain indicate that the slip dissolution model can account for the observed crack growth rates, provided primary rather than secondary creep rates are used. However, approximately 100 cross-sectional TEM foils of SCC cracks including crack tips reveal no evidence of enhanced plasticity or unique dislocation patterns at the crack tip or along the crack to support a classic slip dissolution mechanism. No voids, hydrides, or microcracks are found in the vicinity of the crack tips creating doubt about classic hydrogen related mechanisms. The bulk oxide films exhibit a surface oxide which is often different than the oxides found within a crack. Although bulk chromium concentration affects the rate of SCC, analytical data indicates the mechanism does not result from chromium depletion at the grain boundaries. The overall findings support a corrosion/dissolution mechanism but not one necessarily related to slip at the crack tip

Stress corrosion cracking of alloy 182 weld in a PWR water environment

International Nuclear Information System (INIS)

Lima, Luciana Iglesias Lourenco; Schvartzman, Monica Maria de Abreu Mendonca; Quinan, Marco Antonio Dutra; Soares, Antonio Edicleto Gomes; Piva, Stephano P.T.

2011-01-01

The weld used to connect two different metals is known as dissimilar metal welds (DMW). In the nuclear power plant, this weld is used to join stainless steel nipples to low alloy carbon steel components on the nuclear pressurized water reactor (PWR). In most cases, nickel alloys are used to joint these materials. These alloys are known to accommodate the differences in composition and thermal expansion of the two materials. The stress corrosion cracking (SCC) is a phenomenon that occurs in nuclear power plants metallic components where susceptibility materials are subjected to the simultaneously effect of mechanical stress and an aggressive media with different compositions. SCC is one of degradation process that gradually introduces damage of components, change their characteristics with the operation time. The nickel alloy 600, and their weld metals (nickel alloys 82 and 182), originally selected due to its high corrosion resistance, it exhibit after long operation period (20 years), susceptibility to the SCC. This study presents a comparative work between the SCC in the Alloy 182 filler metal weld in two different temperatures (303 deg C and 325 deg C) in primary water. The susceptibility to stress corrosion cracking was assessed using the slow strain rate tensile (SSRT) test. The results of the SSRT tests indicated that SCC is a thermally-activated mechanism and that brittle fracture caused by the corrosion process was observed at 325 deg C. (author)

Effects of Aging on the Localized and Stress Corrosion of AlLi 2090 Alloy in Deaerated 3.5% NaCl

International Nuclear Information System (INIS)

Kim, Hee San; Suh, Min Suk; Kwon, Hyuk Sang; Lee, Weung Jo

1995-01-01

Effects of aging on the localized and stress corrosion of AlLi 2090 alloy were investigated by measuring relevant critical potentials using cyclic polarization test and constant extention rate test (CERT) in a deaerated 3.5% NaCl solution at 30 .deg. C. The resistance to localized corrosion, when evaluated in terms of the film breakdown potential (E b ) and repassivation potential (E rp ) from cyclic polarization curve measured potentiodynamically, decreased with aging. Pitting corrosion initiated at Al-Fe-Cu particles, which was confirmed by the enrichment of Fe and Cu inside of pit. Stress corrosion cracking of 2090 alloy aged did not occur under freely corroding condition when load applied in longitudinal transverse direction. The susceptibility to SCC of the alloy, however, was very sensitive to applied potentials. At applied potentials above E b , the SCC susceptibility increased with applied potential. On the other hand, at potentials below E rp , the SCC susceptibility decreased with decreasing the applied potential. The critical cracking potential (E cc ) of aged 2090 alloy was found to exist between E b and E rp when SCC was assumed to occur at the strain to failure ratio (ε NaCl /ε air ) lower than 0.8. The resistance to SCC decreased in the order of underaging, peak aging and overaging, that is, with aging. The cracking mechanism of the alloy was well explained by the active path mechanism

Testing of the BipiColombo Antenna Pointing Mechanism

Science.gov (United States)

Campo, Pablo; Barrio, Aingeru; Martin, Fernando

2015-09-01

BepiColombo is an ESA mission to Mercury, its planetary orbiter (MPO) has two antenna pointing mechanism, High gain antenna (HGA) pointing mechanism steers and points a large reflector which is integrated at system level by TAS-I Rome. Medium gain antenna (MGA) APM points a 1.5 m boom with a horn antenna. Both radiating elements are exposed to sun fluxes as high as 10 solar constants without protections.A previous paper [1] described the design and development process to solve the challenges of performing in harsh environment.. Current paper is focused on the testing process of the qualification units. Testing performance of antenna pointing mechanism in its specific environmental conditions has required special set-up and techniques. The process has provided valuable feedback on the design and the testing methods which have been included in the PFM design and tests.Some of the technologies and components were developed on dedicated items priort to EQM, but once integrated, test behaviour had relevant differences.Some of the major concerns for the APM testing are:- Create during the thermal vacuum testing the qualification temperature map with gradients along the APM. From of 200oC to 70oC.- Test in that conditions the radio frequency and pointing performances adding also high RF power to check the power handling and self-heating of the rotary joint.- Test in life up to 12000 equivalent APM revolutions, that is 14.3 million motor revolutions in different thermal conditions.- Measure low thermal distortion of the mechanical chain, being at the same time insulated from external environment and interfaces (55 arcsec pointing error)- Perform deployment of large items guaranteeing during the process low humidity, below 5% to protect dry lubrication- Verify stability with representative inertia of large boom or reflector 20 Kgm2.

Self-healing of mechanically-loaded self consolidating concretes with high volumes of fly ash

Energy Technology Data Exchange (ETDEWEB)

Mustafa Sahmaran; Suleyman B. Keskin; Gozde Ozerkan; Ismail O. Yaman [University of Gaziantep, Gaziantep (Turkey). Department of Civil Engineering

2008-11-15

This article discusses the effects of self-healing on self consolidating concretes incorporating high volumes of fly ash (HVFA-SCC) when subjected to continuous water exposure. For this purpose, self consolidating concretes with fly ash replacement ratios of 0%, 35%, and 55% were prepared having a constant water-cementitious material ratio of 0.35. A uniaxial compression load was applied to generate microcracks in concrete where cylindrical specimens were pre-loaded up to 70% and 90% of the ultimate compressive load determined at 28 days. Later, the extent of damage was determined as percentage of loss in mechanical properties and percentage of increase in permeation properties. After pre-loading, concrete specimens were stored in water for a month and the mechanical and permeation properties are monitored at every two weeks. It was observed that HVFA-SCC mixtures initially lost 27% of their strength when pre-loaded up to 90% of their ultimate strength, and after 30 days of water curing that reduction was only 7%, indicating a substantial healing. On the other hand, for SCC specimens without fly ash that were pre-loaded to the same level, the loss in strength was initially 19%, and after a month of moist curing it was only 13%. Similar observations were also made on the permeation properties with greater effects. As the HVFA-SCCs studied have an important amount of unhydrated fly ash available in their microstructure, these observations are attributed to the self-healing of the pre-existing cracks, mainly by hydration of anhydrous fly ash particles on the crack surfaces.

Achievements and Future Plans of CLIC Test Facilities

CERN Document Server

Braun, Hans Heinrich

2001-01-01

CTF2 was originally designed to demonstrate the feasibility of two-beam acceleration with high current drive beams and a string of 30 GHz CLIC accelerating structure prototypes (CAS). This goal was achieved in 1999 and the facility has since been modified to focus on high gradient testing of CAS's and 30 GHz single cell cavities (SCC). With these modifications, it is now possible to provide 30 GHz RF pulses of more than 150 MW and an adjustable pulselength from 3 to 15 ns. While the SCC results are promising, the testing of CAS's revealed problems of RF breakdown and related surface damage. As a consequence, a new R&D program has been launched to advance the understanding of RF breakdown processes, to improve surface properties, investigate new materials and to optimise the structure geometries of the CAS's. In parallel the construction of a new facility named CTF3 has started. CTF3 will mainly serve two purposes. The first is the demonstration of the CLIC drive beam generation scheme. CTF3 will acceler-a...

Constant Load SCC Initiation Response of Alloy 22 (UNS N06022), Titanium Grade 7 and Stainless Steels at 1050C

International Nuclear Information System (INIS)

Young, L.M.; Catlin, G.M.; Andresen, P.L.; Gordon, G.M.

2002-01-01

This paper provides an update on research addressing the effects of material condition and applied stress on stress corrosion cracking (SCC) in waste package and drip shield materials for the Yucca Mountain Project. Time-to-failure experiments are being performed on smooth bar tensile specimens in a hot, concentrated, mixed-salt solution chosen to simulate concentrated Yucca Mountain water. The effects of applied stress, welding, surface finish, shot peening, cold work, crevicing, and aging treatment are being investigated for Alloy 22 (UNS N06022). Aging treatments were designed to produce topologically close-packed phases (TCP) and long-range ordering (LRO) and are under investigation as worse-case scenarios for possible microstructures in Alloy 22 (UNS N06022). Titanium Grade 7 and 3 16NG stainless steel are included in the matrix, as they are identified for drip shield and waste package components, respectively. Sensitized 304SS specimens are included in the test matrix to provide benchmark data. This research complements high-resolution crack-growth-rate experiments currently being performed in a parallel research project

Stress corrosion cracking of nickel base alloys in PWR primary water

International Nuclear Information System (INIS)

Guerre, C.; Chaumun, E.; Crepin, J.; De Curieres, I.; Duhamel, C.; Heripre, E.; Herms, E.; Laghoutaris, P.; Molins, R.; Sennour, M.; Vaillant, F.

2013-01-01

Stress corrosion cracking (SCC) of nickel base alloys and associated weld metals in primary water is one of the major concerns for pressurized water reactors (PWR). Since the 90's, highly cold-worked stainless steels (non-sensitized) were also found to be susceptible to SCC in PWR primary water ([1], [2], [3]). In the context of the life extension of pressurized water reactors, laboratory studies are performed in order to evaluate the SCC behaviour of components made of nickel base alloys and of stainless steels. Some examples of these laboratory studies performed at CEA will be given in the talk. This presentation deals with both initiation and propagation of stress corrosion cracks. The aims of these studies is, on one hand, to obtain more data regarding initiation time or crack growth rate and, one the other hand, to improve our knowledge of the SCC mechanisms. The aim of these approaches is to model SCC and to predict components life duration. Crack growth rate (CGR) tests on Alloy 82 with and without post weld heat treatment are performed in PWR primary water (Figure 1). The heat treatment seems to be highly beneficial by decreasing the CGR. This result could be explained by the effect of thermal treatment on the grain boundary nano-scopic precipitation in Alloy 82 [4]. The susceptibility to SCC of cold worked austenitic stainless steels is also studied. It is shown that for a given cold-working procedure, SCC susceptibility increases with increasing cold-work ([2], [5]). Despite the fact that the SCC behaviour of Alloy 600 has been widely studied for many years, recent laboratory experiments and analysis ([6], [7], [8]) showed that oxygen diffusion is not a rate-limiting step in the SCC mechanism and that chromium diffusion in the bulk close the crack tip could be a key parameter. (authors)

Stress corrosion cracking of Ni-Fe-Cr alloys in acid sulfate environments relevant to CANDU steam generators

Energy Technology Data Exchange (ETDEWEB)

Persaud, S.Y.; Carcea, A.G., E-mail: suraj.persaud@mail.utoronto.ca [Univ. of Toronto, Toronto, ON (Canada); Huang, J.; Korinek, A.; Botton, G.A. [McMaster Univ., Hamilton, ON (Canada); Newman, R.C. [Univ. of Toronto, Toronto, ON (Canada)

2014-07-01

Ni-Fe-Cr alloys used in nuclear plants have been found susceptible to stress corrosion cracking (SCC) in acid sulfate environments. Electrochemical measurements and SCC tests were done using Ni, Alloy 600, and Alloy 800 in acid sulfate solutions at 315 {sup o}C. Electrochemical measurements suggested that sulfate is a particularly aggressive anion in mixed chloride systems. Cracks with lengths in excess of 300 μm were present on stressed Alloy 800 samples after 60 hours. High resolution analytical electron microscopy was used to extract a crack tip from an Alloy 800 sample and draw final conclusions with respect to the mechanism of SCC. (author)

Mucins CA 125, CA 19.9, CA 15.3 and TAG-72.3 as tumor markers in patients with lung cancer: comparison with CYFRA 21-1, CEA, SCC and NSE.

Science.gov (United States)

Molina, Rafael; Auge, Jose Maria; Escudero, Jose Miguel; Marrades, Ramon; Viñolas, Nuria; Carcereny, Emilio; Ramirez, Jose; Filella, Xavier

2008-01-01

Tumor marker serum levels were prospectively studied in 289 patients with suspected, but unconfirmed, lung cancer and in 513 patients with lung cancer [417 non-small cell lung cancer (NSCLC) patients and 96 small cell lung cancer (SCLC) patients]. In patients with benign disease, abnormal serum levels were found for the following tumor markers: CEA (in 6.6% of patients); CA 19.9 (6.2%); CA 125 (28.7%); NSE (0.7%); CYFRA (8.7%); TAG-72.3 (4.2%); SCC (3.5%), and CA 15.3 (3.5%). Excluding patients with renal failure or liver diseases, tumor marker specificity improved with abnormal levels in 0.5% for NSE, 0.9% for SCC, 2.8% for CEA, CA 15.3 and TAG-72.3, 3.8% for CA 19.9, 4.2% for CYFRA and 21.4% for CA 125. Excluding CA 125, one of the markers was abnormal in 15% of patients without malignancy. Tumor marker sensitivity was related to cancer histology and tumor extension. NSE had the highest sensitivity in SCLC and CYFRA and CEA in NSCLC. Significantly higher concentrations of CEA, SCC, CA 125, CA 15.3 and TAG-72.3 were found in NSCLC than in SCLC. Likewise, significantly higher CEA (p tumors. Using a combination of 3 tumor markers (CEA, CYFRA 21-1 in all histologies, SCC in squamous tumors and CA 15.3 in adenocarcinomas), a high sensitivity may be achieved in all histological types. Tumor markers may be useful in the histological differentiation of NSCLC and SCLC. Using specific criteria for the differentiation of SCLC and NSCLC, the sensitivity was 84.2 and 68.8%, the specificity was 93.8 and 99.7%, the positive predictive value was 98.3 and 98.5% and the negative predictive value was 57.7 and 93.3%, respectively. Copyright 2008 S. Karger AG, Basel.

Comparative Studies on microstructure, mechanical and corrosion behaviour of DMR 249A Steel and its welds

Science.gov (United States)

Mohammed, Raffi; Dilkush; Madhusudhan Reddy, G.; Srinivasa Rao, K.

2018-03-01

DMR249A Medium strength (low carbon) Low-alloy steels are used as structural components in naval applications due to its low cost and high availability. An attempt has been made to weld the DMR 249A steel plates of 8mm thickness using shielded metal arc welding (SMAW) and gas tungsten arc welding (GTAW). Welds were characterized for metallography to carry out the microstructural changes, mechanical properties were evaluated using vickers hardness tester and universal testing machine. Potentio-dynamic polarization tests were carried out to determine the pitting corrosion behaviour. Constant load type Stress corrosion cracking (SCC) testing was done to observe the cracking tendency of the joints in a 3.5%NaCl solution. Results of the present study established that SMA welds resulted in formation of relatively higher amount of martensite in ferrite matrix when compared to gas tungsten arc welding (GTAW). It is attributed to faster cooling rates achieved due to high thermal efficiency. Improved mechanical properties were observed for the SMA welds and are due to higher amount of martensite. Pitting corrosion and stress corrosion cracking resistance of SMA welds were poor when compared to GTA welds.

Slow strain rate corrosion and fracture characteristics of X-52 and X-70 pipeline steels

International Nuclear Information System (INIS)

Contreras, A.; Albiter, A.; Salazar, M.; Perez, R.

2005-01-01

The susceptibility to stress corrosion cracking (SCC) in a NACE solution saturated with H 2 S, of the X-52 and X-70 steels was studied using slow strain rate tests (SSRT) and electrochemical evaluations. SCC tests were performed in samples which include the longitudinal weld bead of the pipeline steels and were carried out in the NACE solution at both room temperature and 50 deg. C. After failure, the fracture surfaces were observed in a scanning electron microscope (SEM) and the chemical analysis were obtained using X-rays energy dispersive (EDXs) techniques. The specimens tested in air, exhibited a ductile type of failure, and whereas, those tested in the corrosive solution showed a brittle fracture. Specimens tested in the NACE solution saturated with H 2 S presented high susceptibility to SCC. Corrosion was found to be an important factor in the initiation of some cracks. In addition, the effect of the temperature on the corrosion attack was explored. The susceptibility to SCC was manifested as a decrease in the mechanical properties. Potentiodynamic polarization curves and hydrogen permeation measurements were made. The diffusion of atomic hydrogen was related to this fracture forms. The hydrogen permeation flux increased with the increasing of temperature

Comparative study of fracture mechanical test methods for concrete

DEFF Research Database (Denmark)

Østergaard, Lennart; Olesen, John Forbes

2004-01-01

and the interpretation, i.e. the analysis needed to extract the stress-crack opening relationship, the fracture energy etc. Experiments are carried out with each test configuration using mature, high performance concrete. The results show that the UTT is a highly complicated test, which only under very well controlled...... circumstances will yield the true fracture mechanical properties. It is also shown that both the three point bending test and the WST are well-suited substitutes for the uniaxial tension test.......This paper describes and compares three different fracture mechanical test methods; the uniaxial tension test (UTT), the three point bending test (TPBT) and the wedge splitting test (WST). Potentials and problems with the test methods will be described with regard to the experiment...

Miniaturization of specimens for mechanical testing

International Nuclear Information System (INIS)

Harling, O.K.; Kohse, G.

1987-01-01

The development of mechanical property tests based on bending of a 3 mm diameter by (typically) 0.25 mm thick disk is described. Slow strain rate testing of such a disk is used to obtain tensile properties. Finite element computer modelling is used to extract yield stress values with accuracies of at least +- 10% of uniaxial tensile test values for a variety of materials. Analytical estimates of ductility from disk bend test values are possible for low-ductility materials. Work directed toward finite element calculations for ductility and ultimate tensile strength is also discussed. Preliminary data indicating the feasibility of high strain rate testing for estimation of ductile-to-brittle transition temperatures, and an example of the successful application of miniature bend testing in obtaining relative fatigue information are also presented. (author)

PWR type overpower tests at 1620 GJ/KGU (18,800 MWD/MTU)

International Nuclear Information System (INIS)

Knudsen, P.; Bagger, C.; Carlsen, H.

1979-01-01

Three PWR type test fuel pins accumulated a burnup of 1620 GJ/kgU at heat loads decreasing from 45 to 28 kW/m (avg. test levels). One pin was ramped to 43 kW/m at 31 W/m/s; after 15 ks the power was increased to 45 kW/m and held constant for 1.9 Ms without failure indication. The other two pins were ramped to 44 kW/m at 23 W/m/s and then to 49 kW/m in a further 1.2 ks; both failed after max. 360 s. The post-irradiation examination revealed large stress-corrosion (SCC) type cladding cracks. Other cracks, down to a few μm deep, were probably early stages of large SCC cracks. Fission gas release in the intact pin was as high as 42% and estimated to be much lower for the two failed pins

A Fractual Mechanical Testing and Design Strategy for FRC Structures

DEFF Research Database (Denmark)

Stang, Henrik; Olesen, John Forbes

1999-01-01

A unified testing and design strategy for fibre reinforced concrete structures is summarised. The strategy is based on fracture mechanical concepts. Emphasis is placed on material characterisation and testing specifications.......A unified testing and design strategy for fibre reinforced concrete structures is summarised. The strategy is based on fracture mechanical concepts. Emphasis is placed on material characterisation and testing specifications....

Auditory Automotive Mechanics Diagnostic Achievement Test. Center Technical Paper No. 2.

Science.gov (United States)

Swanson, Richard Arthur

The Auditory Automotive Mechanics Diagnostic Achievement Test assesses an automobile mechanic's ability to determine mechanical faults from auditory cues alone. The 44-item test and its instructions are recorded on magnetic tape; answer choices are presented on tape, and are also written in the printed test booklets. The norming and validity…

DFTB3: Extension of the self-consistent-charge density-functional tight-binding method (SCC-DFTB).

Science.gov (United States)

Gaus, Michael; Cui, Qiang; Elstner, Marcus

2012-04-10

The self-consistent-charge density-functional tight-binding method (SCC-DFTB) is an approximate quantum chemical method derived from density functional theory (DFT) based on a second-order expansion of the DFT total energy around a reference density. In the present study we combine earlier extensions and improve them consistently with, first, an improved Coulomb interaction between atomic partial charges, and second, the complete third-order expansion of the DFT total energy. These modifications lead us to the next generation of the DFTB methodology called DFTB3, which substantially improves the description of charged systems containing elements C, H, N, O, and P, especially regarding hydrogen binding energies and proton affinities. As a result, DFTB3 is particularly applicable to biomolecular systems. Remaining challenges and possible solutions are also briefly discussed.

SCC of Alloy 600 components in PWR primary loop

International Nuclear Information System (INIS)

Gomez-Briceno, Dolores; Lapena, Jesus; Castano, M. Luisa; Blazquez, Fernando

2002-01-01

initiation time has been determined. A detailed fractographic study of the fracture surface points out that the appearance of the fracture, intergranular in all the cases, is related to the susceptibility of the material. For the crack growth rate test, CT specimens tested under constant load were used. Specimens were fabricated from five Alloy 600 heats (two forged bars, cold work and hot work tubes, and a plate) with yield strength ranging from 280 to 413 MPa. Crack growth rate data were obtained at temperatures between 290 and 330 deg. C. Activation energy for both processes, crack initiation and propagation has been determined. On the other hand, in January 1994, during a refueling outage, an ID axial throughwall crack was detected in one of the RVH nozzle of Jose Cabrera Nuclear Plant in Spain. Extensive NDE examination of all the vessel head penetrations confirmed ID axially oriented indications in several of the nozzles. The cause of the extensive cracking detected was identified as an IGA/SCC process in primary water contaminated with sulphur species due to a cation resin ingress in the primary loop during the early 1980s. In order to confirm the postulated degradation process and to assess its relevance for other alloy 600 components in the reactor primary loop, an experimental program was performed. The scope of this program included to study the behaviour of sensitised alloy 600 in the water conditions postulated as the cause of the cracking and to obtain crack growth rate data in similar conditions, at 285 and 325 deg. C. In addition, the behaviour of the sensitised alloy 600 in shutdown conditions was also studied. In this paper the main results of these experimental programs, including no published data, will be presented and discussed in the light of the available results from other laboratories. (author)

Mechanical/structural performance test method of a spacer grid

International Nuclear Information System (INIS)

Yoon, Kyung Ho

2000-06-01

The spacer grid is one of the main structural components in the fuel assembly, which supports the fuel rods, guides cooling water, and protects the system from an external impact load, such as earthquakes. In order to develop the spacer grid with the high mechanical performance, the mechanical and structural properties of the spacer grids must be extensively examined while designing it. In this report, the mechanical/structural test methods, i.e. the characteristic test of a spacer grid spring or dimple, static buckling test of a partial or full size spacer grid and dynamic impact test of them are described. The characteristic test of a spacer grid spring or dimple is accomplished with universal tensile test machine, a specimen is fixed with test fixture and then applied compressive load. The characteristic test data is saved at loading and unloading event. The static buckling test of a partial or full size spacer grid is executed with the same universal tensile testing machine, a specimen is fixed between cross-heads and then applied the compressive load. The buckling strength is decided the maximum strength at load vs. displacement curve. The dynamic impact test of a partial or full size spacer grid is performed with pendulum type impact machine and free fall shock test machine, a specimen is fixed with test fixture and then applied the impact load by impact hammer. Specially, the pendulum type impact test machine is also possible under the operating temperature because a furnace is separately attached with test machine

Testing and Modeling of Mechanical Characteristics of Resistance Welding Machines

DEFF Research Database (Denmark)

Wu, Pei; Zhang, Wenqi; Bay, Niels

2003-01-01

for both upper and lower electrode systems. This has laid a foundation for modeling the welding process and selecting the welding parameters considering the machine factors. The method is straightforward and easy to be applied in industry since the whole procedure is based on tests with no requirements......The dynamic mechanical response of resistance welding machine is very important to the weld quality in resistance welding especially in projection welding when collapse or deformation of work piece occurs. It is mainly governed by the mechanical parameters of machine. In this paper, a mathematical...... model for characterizing the dynamic mechanical responses of machine and a special test set-up called breaking test set-up are developed. Based on the model and the test results, the mechanical parameters of machine are determined, including the equivalent mass, damping coefficient, and stiffness...

Design of cost-effective M 25 grade of self compacting concrete

International Nuclear Information System (INIS)

Guru Jawahar, J.; Sashidhar, C.; Ramana Reddy, I.V.; Annie Peter, J.

2013-01-01

Highlights: ► Design of cost-effective M 25 grade of self compacting concrete is done. ► Mechanical properties of SCC compared with M 25 grade of conventional concrete. ► Effect of class F fly ash is studied on the SCC mechanical properties. ► Cost analysis is done between M 25 grade of CC and SCC. ► Recommendation of M 25 grade of SCC for normal building constructions. - Abstract: This investigation is mainly focused on the development of cost-effective normal strength M 25 grade of self compacting concrete (SCC) for the use of normal building constructions. Keeping in view of the normal strength, cost, quality and durability of SCC and greenhouse gas emissions, a combination type of SCC was developed with 35% replacement of cement with class F fly ash. This study recommended a SCC mix with moderate fines to obtain a cost-effective normal strength SCC for the normal building constructions. Studies also revealed that further reduction in fines content in SCC with the same replacement level of fly ash decreased the SCC strength and its performance. Cost analysis has been done between M 25 grade of SCC and conventional concrete (CC). Results shown that the SCC material cost is slightly higher than that of CC of the same strength class, but the savings in labour cost and construction time and quality of SCC would offset the SCC material cost and reduce the total life cycle cost of SCC

Testing and assessment of low alloy steel for marine application

International Nuclear Information System (INIS)

Amjad, M.; Ahmad, S.; Mahmood, K.; Qureshi, A.H.

2007-01-01

This paper is an account of the work carried out during the assessment of low alloy steel (WH-80) for marine application. The relevant acceptance criteria consulted during the process is DEFST AN 02-874 and a standard reference material. Assessment is based on the experimental results of the tests carried out for the steel. Testing comprised of mechanical (tensile, impact and hardness) tests, corrosion (immersion corrosion and stress corrosion cracking) tests, metallography test and weldability (weld joint strength, controlled thermal severity -CTS and Y -Groove) tests undertaken at various testing laboratories in Pakistan. The results obtained after testing have been compared with acceptance criteria (DEFSTAN 02-874 and standard reference material). Moreover results have been compared with contemporary steels used for marine applications. Results showed a reasonable agreement with results available in literature for other low alloy steels with respect to mechanical strength and weldability. Steel weldments qualified the weld joint strength tests and weldability tests. Toughness has been measured at various temperatures. Results revealed that the toughness of base metal is higher than heat affected zone (HAZ) and weld metal. In weldability tests, weld metal and HAZ were examined microscopically to investigate integrity of weld. No cracks have been observed in the weld which indicates complete diffusion in to the welding material. WH- 80 steel has exhibited comparatively high corrosion rate, reduction in tensile strength during SCC test and low Charpy energy values at -50 degree C. It is therefore concluded that the WH-80 steel is unsuitable for use in application at subzero (OC) temperatures and in highly corrosive environment. (author)

Testing lung cancer drugs and therapies in mice

Science.gov (United States)

National Cancer Institute (NCI) investigators have designed a genetically engineered mouse for use in the study of human lung squamous cell carcinoma (SCC). SCC is a type of non-small cell lung carcinoma, one of the most common types of lung cancer, with

PEMANFAATAN REBUSAN DAUN SIRIH MERAH (Piper crocatum DALAM MENURUNKAN TINGKAT KEJADIAN MASTITIS BERDASARKANN UJI CMT DAN SCC

Directory of Open Access Journals (Sweden)

Razan Harastha Sjuhada

2017-11-01

Full Text Available The red betel leaves (Piper crocatum known as herbal antiseptic that contain many substances like essential oil, flavonoid, saponin, and tannin. The red betel leaves can be use to replace chemical antiseptic and more safe to use for teat dipping for dairy cow. The purpose of this research was to determine the effect of teat dipping with red betel leaves decoction to decrease subclinical mastitis level and somatic cell based on CMT and SCC. The method in this research was experiment with Randomize Block Design with 3 treatments and 5 replications. The data analyzed with Analysis of Variance (ANOVA, if there were significant effects it would be continue by Duncan’s Multiple Range Test (DMRT. The results showed that teat dipping with red betel leaves decoction had a significant different (P<0.05 to decrease mastitis level. Teat dipping with red betel leaves decoction 20% concentration could decrease mastitis level up to 30%. Teat dipping with red betel leaves decoction had a significant difference (P<0.05 to decrease the amount of somatic cell too. Teat dipping with red betel leaves stew 20% concentration could decrease the amount of somatic cell up to 1.98% or 0.12CFU/ml. The conclusion that teat dipping with red betel leaves decoction 20% was the best concentration and gave the best results to decrease mastitis level and somatic cell.

Item response theory analysis of the mechanics baseline test

Science.gov (United States)

Cardamone, Caroline N.; Abbott, Jonathan E.; Rayyan, Saif; Seaton, Daniel T.; Pawl, Andrew; Pritchard, David E.

2012-02-01

Item response theory is useful in both the development and evaluation of assessments and in computing standardized measures of student performance. In item response theory, individual parameters (difficulty, discrimination) for each item or question are fit by item response models. These parameters provide a means for evaluating a test and offer a better measure of student skill than a raw test score, because each skill calculation considers not only the number of questions answered correctly, but the individual properties of all questions answered. Here, we present the results from an analysis of the Mechanics Baseline Test given at MIT during 2005-2010. Using the item parameters, we identify questions on the Mechanics Baseline Test that are not effective in discriminating between MIT students of different abilities. We show that a limited subset of the highest quality questions on the Mechanics Baseline Test returns accurate measures of student skill. We compare student skills as determined by item response theory to the more traditional measurement of the raw score and show that a comparable measure of learning gain can be computed.

Effect of cold work hardening on stress corrosion cracking of stainless steels in primary water of pressurized water reactors

International Nuclear Information System (INIS)

Raquet, O.; Herms, E.; Vaillant, F.; Couvant, T.; Boursier, J.M.

2004-01-01

A R and D program is carried out in CEA and EDF laboratories to investigate separately the effects of factors which could contribute to IASCC mechanism. In the framework of this study, the influence of cold work on SCC of ASSs in primary water is studied to supply additional knowledge concerning the contribution of radiation hardening on IASCC of ASSs. Solution annealed ASSs, essentially of type AISI 304(L) and AISI 316(L), are generally considered very resistant to SCC in nominal primary water. However, Constant Extension Rate Tests (CERTs), performed on cold pressed humped specimens in nominal primary water at 360 deg. C, reveal that these materials can exhibit a high SCC susceptibility: deepest cracks reach 1 mm (mean crack growth rate about 1 μm.h -1 ) and propagation is mainly intergranular for 304L and mainly transgranular for 316L. Indeed, work hardening in conjunction with high localized deformation can promote SCC. The influence of the nature of the cold work (shot peening, reaming, cold rolling, counter sinking, fatigue work hardening and tensile deformation) is investigated by means of screening CERTs performed with smooth specimens in 304L at 360 deg. C. For a given cold work hardening level, the susceptibility to crack initiation strongly depends on the cold working process, and no propagation is observed for a hardness level lower than 300 ±10 HV(0.49N). The propagation of cracks is observed only for dynamic loadings like CERT, traction/relaxation tests and crack growth rate tests performed with CT specimens under trapezoidal loading. Although crack initiation is observed for constant load and constant deformation tests, crack propagation do not seem to occur under these mechanical solicitations for 17000 hours of testing, even for hardness levels higher than 450 HV(0.49N). The mean crack growth rate increases when the hardness increases. An important R and D program is in progress to complement these results and to develop a SCC model for ASSs in

Prophylactic dissection of level V in primary mucosal SCC in the clinically N positive neck: A systematic review.

Science.gov (United States)

McLean, Timothy; Kerr, Stephen J; Giddings, Charles E B

2017-09-01

To review the evidence for level V dissection in the management of previously untreated mucosal squamous cell carcinoma (SCC) of the head and neck presenting with nodal metastasis when level V is clinically uninvolved. The Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) were used to conduct a systematic review of the current literature, including all English language articles published after 1990. A literature search was performed on November 29, 2015, of Medline, EMBASE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and the Cochrane Library. The search yielded a total of 270 papers. Strict inclusion and exclusion criteria were applied, leaving 20 eligible papers. Overall prevalence was calculated using random effect meta-analysis. The overall prevalence of level V occult disease in the node (N)-positive neck, irrespective of subsite, was 2.56% (95% confidence interval 1.29-3.84) (2,368 patients and 2,533 necks). The prevalence of occult level V metastasis was up to 7.7% for oral cavity and 8.3% for oropharyngeal tumors. Five studies reported regional recurrence rates over variable time periods. There is exceedingly limited data on outcomes, such as spinal accessory nerve function, quality of life, and perioperative complications. Mucosal head and neck SCC presenting with nodal metastasis but with level V clinically uninvolved has a low prevalence of occult level V disease. Routine dissection of level V does not appear to be warranted; however, a definitive conclusion is unable to be drawn due to limited data on morbidity and oncological outcomes. Laryngoscope, 127:2074-2080, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Present status of the disk pressure tests for hydrogen embrittlements

International Nuclear Information System (INIS)

Fidelle, J.P.

1988-01-01

The Disk Pressure Tests (DPT) have been developed considerably. Theoretically: a finite elements mechanical analysis shows the build up of a triaxial stress state already at the beginning of the test, which, with other reasons accounts for the very high sensitivity. Experimentally: for Internal Hydrogen Embrittlement (IHE) e.g. Co, Ti, U alloys, for environment embrittlement due to H 2 hydrogenated media such as water vapor, alcohol, machining fluids or liquid NH 3 . The range has been expanded considerably: up to 300 MPa and up to 1000 0 C. Very low strain rate - longer than a month - tests have been able to evidence HGE; of FCC alloys where H diffusivity is low for very oxidation -sensitive metals such as Nb and Ta, effects may appear only at somewhat high rates. The relationship between dynamic tests, static and low-cycle fatigue tests has been determined. In a number of instances, including SCC, other techniques and even fracture mechanics have been compared to the DPT and proved at best equivalent and several times, less sensitive than a well conducted DPT. At extreme they could not reproduce the field service phenomenon whereas the DPT did and could also be applied satisfactorily to low yield stress materials. The main rupture aspects have been analysed mechanically and organized in a rational and comprehensive chart based on 12,000 + tests over 15O + materials in different conditions. Comparison of HGE tests and service behaviour of a large variety of materials and industrial equipments has made possible to specify acceptance criteria for industrial service, which, provided the shape of the stress strain curves is not significantly affected, can be expanded to IHE, HE by other fluids than H 2 , 36 refs

Receiver-operating characteristic curves for somatic cell scores and California mastitis test in Valle del Be lice dairy sheep

NARCIS (Netherlands)

Riggio, V.; Pesce, L.L.; Morreale, S.; Portolano, B.

2013-01-01

Using receiver-operating characteristic (ROC) curve methodology this study was designed to assess the diagnostic effectiveness of somatic cell count (SCC) and the California mastitis test (CMT) in Valle del Belice sheep, and to propose and evaluate threshold values for those tests that would

Nondestructive mechanical characterization of developing biological tissues using inflation testing.

Science.gov (United States)

Oomen, P J A; van Kelle, M A J; Oomens, C W J; Bouten, C V C; Loerakker, S

2017-10-01

One of the hallmarks of biological soft tissues is their capacity to grow and remodel in response to changes in their environment. Although it is well-accepted that these processes occur at least partly to maintain a mechanical homeostasis, it remains unclear which mechanical constituent(s) determine(s) mechanical homeostasis. In the current study a nondestructive mechanical test and a two-step inverse analysis method were developed and validated to nondestructively estimate the mechanical properties of biological tissue during tissue culture. Nondestructive mechanical testing was achieved by performing an inflation test on tissues that were cultured inside a bioreactor, while the tissue displacement and thickness were nondestructively measured using ultrasound. The material parameters were estimated by an inverse finite element scheme, which was preceded by an analytical estimation step to rapidly obtain an initial estimate that already approximated the final solution. The efficiency and accuracy of the two-step inverse method was demonstrated on virtual experiments of several material types with known parameters. PDMS samples were used to demonstrate the method's feasibility, where it was shown that the proposed method yielded similar results to tensile testing. Finally, the method was applied to estimate the material properties of tissue-engineered constructs. Via this method, the evolution of mechanical properties during tissue growth and remodeling can now be monitored in a well-controlled system. The outcomes can be used to determine various mechanical constituents and to assess their contribution to mechanical homeostasis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Use of domestic detergents in the California mastitis test for high somatic cell counts in milk.

Science.gov (United States)

Leach, K A; Green, M J; Breen, J E; Huxley, J N; Macaulay, R; Newton, H T; Bradley, A J

2008-11-08

The California mastitis test (CMT) is used on farms to identify subclinical mastitis by an indirect estimation of the somatic cell count (SCC) in milk. Four commercially available detergents were compared with a bespoke cmt fluid for their ability to detect milk samples with a scc above 200,000 cells/ml; differences between the interpretation of the results of the tests by eight operators were also investigated. The sensitivity and specificity of the test were affected by the type of detergent, and by the operators' interpretations. When used by the most sensitive operator, suitably diluted Fairy Liquid performed almost identically to cmt fluid in identifying milk samples with more than 200,000 cells/ml. The average sensitivities achieved by the eight operators for detecting this threshold were 82 per cent for Fairy Liquid and 84 per cent for cmt fluid, and the specificities were 93 and 91 per cent respectively. The other detergents contained less anionic surfactants and were less sensitive but similarly specific.

Testing quantum mechanics using third-order correlations

International Nuclear Information System (INIS)

Kinsler, P.

1996-01-01

Semiclassical theories similar to stochastic electrodynamics are widely used in optics. The distinguishing feature of such theories is that the quantum uncertainty is represented by random statistical fluctuations. They can successfully predict some quantum-mechanical phenomena; for example, the squeezing of the quantum uncertainty in the parametric oscillator. However, since such theories are not equivalent to quantum mechanics, they will not always be useful. Complex number representations can be used to exactly model the quantum uncertainty, but care has to be taken that approximations do not reduce the description to a hidden variable one. This paper helps show the limitations of open-quote open-quote semiclassical theories,close-quote close-quote and helps show where a true quantum-mechanical treatment needs to be used. Third-order correlations are a test that provides a clear distinction between quantum and hidden variable theories in a way analogous to that provided by the open-quote open-quote all or nothing close-quote close-quote Greenberger-Horne-Zeilinger test of local hidden variable theories. copyright 1996 The American Physical Society

Iodine induced stress corrosion cracking of zircaloy cladding tubes

International Nuclear Information System (INIS)

Brunisholz, L.; Lemaignan, C.

1984-01-01

Iodine is considered as one of the major fission products responsible for PCI failure of Zry cladding by stress corrosion cracking (SCC). Usual analysis of SCC involves both initiation and growth as sequential processes. In order to analyse initiation and growth independently and to be able to apply the procedures of fracture mechanics to the design of cladding, with respect to SCC, stress corrosion tests of Zry cladding tubes were undertaken with a small fatigue crack (approx. 200 μm) induced in the inner wall of each tube before pressurization. Details are given on the techniques used to induce the fatigue crack, the pressurization test procedure and the results obtained on stress releaved or recrystallized Zry 4 tubings. It is shown that the Ksub(ISCC) values obtained during these experiments are in good agreement with those obtained from large DCB fracture mechanics samples. Conclusions will be drawn on the applicability of linear elastic fracture mechanics (LEFM) to cladding design and related safety analysis. The work now underway is aimed at obtaining better understanding of the initiation step. It includes the irradiation of Zry samples with heavy ions to simulate the effect of recoil fragments implanted in the inner surface of the cladding, that could create a brittle layer of about 10 μm

The use of a volcanic material as filler in self-compacting concrete production for lower strength applications

Directory of Open Access Journals (Sweden)

D. Burgos

2017-01-01

Full Text Available This study evaluates the use of large amounts of fine powders (fillers derived from a Colombian volcanic material into the production of self-compacting concrete (SCC for lower strength applications. The effects on SCC properties were studied with the incorporation of up to 50% of volcanic material of Tolima (MVT as a partial substitute of the total weight of Portland cement. The workability was determined through slump flow, V-funnel, and L-box test. The compressive strength results were analyzed statistically by MINITAB. These demonstrated that 30% (by total weight of cementitious material was the maximum allowable percentage of MVT to be used in the production of SCCs. Based on this, mechanical and permeability properties of SCC MVT 30% were evaluated at 28, 90 y 360 curing days. SCC MVT 30% exhibited compressive strength of 21 and 27 MPa after 28 and 360 days of curing, respectively.

The use of a volcanic material as filler in self-compacting concrete production for lower strength applications

International Nuclear Information System (INIS)

Burgos, D.; Guzmán, A.; Hossain, K.M.A.; Delvasto, S.

2017-01-01

This study evaluates the use of large amounts of fine powders (fillers) derived from a Colombian volcanic material into the production of self-compacting concrete (SCC) for lower strength applications. The effects on SCC properties were studied with the incorporation of up to 50% of volcanic material of Tolima (MVT) as a partial substitute of the total weight of Portland cement. The workability was determined through slump flow, V-funnel, and L-box test. The compressive strength results were analyzed statistically by MINITAB. These demonstrated that 30% (by total weight of cementitious material) was the maximum allowable percentage of MVT to be used in the production of SCCs. Based on this, mechanical and permeability properties of SCC MVT 30% were evaluated at 28, 90 y 360 curing days. SCC MVT 30% exhibited compressive strength of 21 and 27 MPa after 28 and 360 days of curing, respectively. [es

Mechanical testing of hydraulic fluids II; Mechanische Pruefung von Hydraulikfluessigkeiten II

Energy Technology Data Exchange (ETDEWEB)

Kessler, M.; Feldmann, D.G.; Laukart, V.

2001-09-01

Since May 1996 the Institute for Mechanical Engineering Design 1 of Technical University of Hamburg-Harburg is working on the topic of ''Mechanical Testing of Hydraulic fluids''. The first project lasting 2 1/2 years was completed in 1999, the results are published as the DGMK report 514. Within these project a testing principle for the ''mechanical testing'' of hydraulic fluids has been derived, a prototype of a test rig was designed and set in operation at the authors' institute. This DGMK-report 514-1 describes the results of the second project, which investigates the operating behaviour of the test-rig more in detail. Several test-runs with a total number of 11 different hydraulic fluids show the dependence of the different lubricating behaviour of the tested fluids and their friction and wear behaviour during the tests in a reproducible way. The aim of the project was to derive a testing principle including the design of a suitable test-rig for the mechanical testing of hydraulic fluids. Based on the described results it can be stated that with the developed test it is possible to test the lubricity of hydraulic fluids reproducible and in correlation to field experiences within a relatively short time, so the target was reached. (orig.)

Judgments of Risk Frequencies: Tests of Possible Cognitive Mechanisms

Science.gov (United States)

Hertwig, Ralph; Pachur, Thorsten; Kurzenhauser, Stephanie

2005-01-01

How do people judge which of 2 risks claims more lives per year? The authors specified 4 candidate mechanisms and tested them against people's judgments in 3 risk environments. Two mechanisms, availability by recall and regressed frequency, conformed best to people's choices. The same mechanisms also accounted well for the mapping accuracy of…

System for stress corrosion conditions tests on PWR reactors

International Nuclear Information System (INIS)

Castro, Andre Cesar de Jesus

2007-01-01

The study of environmentally assisted cracking (EAC) involves the consideration and evaluation of the inherent compatibility between a material and the environment under conditions of either applied or residual stress. EAC is a critical problem because equipment, components and structure are subject to the influence of mechanical stress, water environment of different composition, temperature and different material history. Testing for resistance to EAC is one of the most effective ways to determine the interrelationships among this variables on the process of EAC. Up to now, several experimental techniques have been developed worldwide, which address different aspects of environmental caused damage. Constant loading of CT specimens test is a typical example of test, which is used for the estimation of parameters of stress corrosion cracking. To assess the initiation stages and kinetics of crack growth, the testing facility should allow active loading of specimens in the environment that is close to the actual operation conditions of assessed component. This paper presents a testing facility for stress corrosion cracking to be installed at CDTN, which was designed and developed at CDTN. The facility is used to carry out constant load tests under simulated PWR environment, where temperature, water pressure and chemistry are controlled, which are considered the most important factors in SCC. Also, the equipment operational conditions, its applications, and restrictions are presented. The system was developed to operate at temperature until 380 degree C and pressure until 180 bar. It consists in a autoclave stuck at a mechanical system, responsible of producing load , a water treatment station, and a data acquisition system. This testing facility allows the evaluation of cracking progress, especially at PWR reactor. (author) operational conditions. (author)

BWR pipe crack remedies evaluation

International Nuclear Information System (INIS)

Shack, W.J.; Kassner, T.F.; Maiya, P.S.; Park, J.Y.; Ruther, W.; Kuzay, T.; Rybicki, E.F.; Stonesifer, R.B.

1988-01-01

Piping in light-water-reactor power systems has been affected by several types of environmental degradation. This paper presents results from studies of (1) stress corrosion crack growth in fracture mechanics specimens of modified Type 347 SS and Type 304/308L SS weld overlay material, (2) heat-to-heat variations in stress corrosion cracking (SCC) of Types 316NG and 347 SS, (3) SCC of sensitized Type 304 SS in water with cupric ion or organic acid impurities, (4) electrochemical potential (ECP) measurements under gamma irradiation, (5) SCC of ferritic steels, (6) strain-controlled fatigue of Type 316NG SS in air at ambient temperature, and (7) through-wall residual stress measurements and finite-element calculation of residual stresses in weldments treated by a mechanical stress improvement process (MSIP). Fracture-mechanics crack-growth-rate tests on Type 316NG SS have shown that transgranular cracking can occur even in high purity environments, whereas no crack growth was observed in Type 347 SS even in impurity environments. In tests on weld overlay specimens, no cracks penetrated into the overlay even in impurity environments. Instead, the cracks branched when they approached the overlay, and then grew parallel to interface. In SCC tests on sensitized Type 304 SS, cupric ions at concentrations greater than ∼1 ppm were found to be deleterious, whereas organic acids at this concentration were not detrimental. Tests on several ferritic steels indicate a strong correlation between the sulfur content of the steels and susceptibility to SCC. External gamma radiation fields produced a large positive shift in the ECP of Type 304 SS at low dissolved-oxygen concentrations (<5 ppb), whereas in the absence of an external gamma field there was no difference in the ECP values of irradiated and nonirradiated material. Fatigue data for Type 316NG SS are consistent with the ASME code mean curve at high strains, but fall below the curve at low strains. Calculations of the

Finite element simulations of two rock mechanics tests

International Nuclear Information System (INIS)

Dahlke, H.J.; Lott, S.A.

1986-04-01

Rock mechanics tests are performed to determine in situ stress conditions and material properties of an underground rock mass. To design stable underground facilities for the permanent storage of high-level nuclear waste, determination of these properties and conditions is a necessary first step. However, before a test and its associated equipment can be designed, the engineer needs to know the range of expected values to be measured by the instruments. Sensitivity studies by means of finite element simulations are employed in this preliminary design phase to evaluate the pertinent parameters and their effects on the proposed measurements. The simulations, of two typical rock mechanics tests, the plate bearing test and the flat-jack test, by means of the finite element analysis, are described. The plate bearing test is used to determine the rock mass deformation modulus. The flat-jack test is used to determine the in situ stress conditions of the host rock. For the plate bearing test, two finite element models are used to simulate the classic problem of a load on an elastic half space and the actual problem of a plate bearing test in an underground tunnel of circular cross section. For the flat-jack simulation, a single finite element model is used to simulate both horizontal and vertical slots. Results will be compared to closed-form solutions available in the literature

An Adaptive Test Sheet Generation Mechanism Using Genetic Algorithm

Directory of Open Access Journals (Sweden)

Huan-Yu Lin

2012-01-01

Full Text Available For test-sheet composition systems, it is important to adaptively compose test sheets with diverse conceptual scopes, discrimination and difficulty degrees to meet various assessment requirements during real learning situations. Computation time and item exposure rate also influence performance and item bank security. Therefore, this study proposes an Adaptive Test Sheet Generation (ATSG mechanism, where a Candidate Item Selection Strategy adaptively determines candidate test items and conceptual granularities according to desired conceptual scopes, and an Aggregate Objective Function applies Genetic Algorithm (GA to figure out the approximate solution of mixed integer programming problem for the test-sheet composition. Experimental results show that the ATSG mechanism can efficiently, precisely generate test sheets to meet the various assessment requirements than existing ones. Furthermore, according to experimental finding, Fractal Time Series approach can be applied to analyze the self-similarity characteristics of GA’s fitness scores for improving the quality of the test-sheet composition in the near future.

A Proposed Molecular Mechanism of High-Dose Vitamin D3 Supplementation in Prevention and Treatment of Preeclampsia.

Science.gov (United States)

Zabul, Piotr; Wozniak, Michal; Slominski, Andrzej T; Preis, Krzysztof; Gorska, Magdalena; Korozan, Marek; Wieruszewski, Jan; Zmijewski, Michal A; Zabul, Ewa; Tuckey, Robert; Kuban-Jankowska, Alicja; Mickiewicz, Wieslawa; Knap, Narcyz

2015-06-09

A randomized prospective clinical study performed on a group of 74 pregnant women (43 presenting with severe preeclampsia) proved that urinary levels of 15-F(2t)-isoprostane were significantly higher in preeclamptic patients relative to the control (3.05 vs. 2.00 ng/mg creatinine). Surprisingly enough, plasma levels of 25-hydroxyvitamin D3 in both study groups were below the clinical reference range with no significant difference between the groups. In vitro study performed on isolated placental mitochondria and placental cell line showed that suicidal self-oxidation of cytochrome P450scc may lead to structural disintegration of heme, potentially contributing to enhancement of oxidative stress phenomena in the course of preeclampsia. As placental cytochrome P450scc pleiotropic activity is implicated in the metabolism of free radical mediated arachidonic acid derivatives as well as multiple Vitamin D3 hydroxylations and progesterone synthesis, we propose that Vitamin D3 might act as a competitive inhibitor of placental cytochrome P450scc preventing the production of lipid peroxides or excess progesterone synthesis, both of which may contribute to the etiopathogenesis of preeclampsia. The proposed molecular mechanism is in accord with the preliminary clinical observations on the surprisingly high efficacy of high-dose Vitamin D3 supplementation in prevention and treatment of preeclampsia.

Microstructure, local mechanical properties and stress corrosion cracking susceptibility of an SA508-52M-316LN safe-end dissimilar metal weld joint by GTAW

Energy Technology Data Exchange (ETDEWEB)

Ming, Hongliang; Zhu, Ruolin [Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning KeyLaboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049 (China); Zhang, Zhiming [Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning KeyLaboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Wang, Jianqiu, E-mail: wangjianqiu@imr.ac.cn [Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning KeyLaboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Han, En.-Hou.; Ke, Wei [Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning KeyLaboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Su, Mingxing [Shanghai Research Center for Weld and Detection Engineering Technique of Nuclear Equipment, Shanghai 201306 (China)

2016-07-04

The microstructure, local mechanical properties and local stress corrosion cracking susceptibility of an SA508-52M-316LN domestic dissimilar metal welded safe-end joint used for AP1000 nuclear power plant prepared by automatic gas tungsten arc welding was studied in this work by optical microscopy, scanning electron microscopy (with electron back scattering diffraction and an energy dispersive X-ray spectroscopy system), micro-hardness testing, local mechanical tensile testing and local slow strain rate tests. The micro-hardness, local mechanical properties and stress corrosion cracking susceptibility across this dissimilar metal weld joint vary because of the complex microstructure across the fusion area and the dramatic chemical composition change across the fusion lines. Briefly, Type I boundaries and Type II boundaries exist in 52Mb near the SA508-52Mb interface, a microstructure transition was found in SA508 heat affected zone, the residual strain and grain boundary character distribution changes as a function of the distance from the fusion boundary in 316LN heat affected zone, micro-hardness distribution and local mechanical properties along the DMWJ are heterogeneous, and 52Mw-316LN interface has the highest SCC susceptibility in this DMWJ while 316LN base metal has the lowest one.

Mechanical testing of adherence of stacked layers in tubular geometry

Energy Technology Data Exchange (ETDEWEB)

Correia, L.A.; Schuring, E.W.; Van Delft, Y.C. [ECN Energy Efficiency in the Industry, Petten (Netherlands)

2007-09-15

For the development of new molecular separation technologies strong robust tubular membrane systems are required. The fragile membranes, however, need a strong defect free support such as a porous asymmetric ceramic tube. Mechanical failure of these ceramic membrane systems during manufacturing and operation is mainly caused by delamination of the stacked layers. Therefore development is focused on improving the adherence. As no standard mechanical test for tubular samples is available yet, a new tensile test was developed to facilitate the current research. The most important components in the new equipment is a test tool with a curvature matching that of the test sample and a sample casing that align and guide the test tool during the tensile test. With this tensile test the manufacturing procedure for the ECN standard tubular {alpha}-alumina support was optimized. Firing the asymmetric support at 1300C resulted in the highest mechanical strength for the support system with cohesive fracture in the support tube. With the test developed the process condition could be identified where the material of the support tube is the weakest link in the support system.

Thermo-mechanical tests on W7-X current lead flanges

International Nuclear Information System (INIS)

Dhard, Chandra Prakash; Rummel, Thomas; Zacharias, Daniel; Bykov, Victor; Moennich, Thomas; Buscher, Klaus-Peter

2013-01-01

Highlights: • There are significant mechanical loads on the cryostat and radial flanges for W7-X current leads. • These are due to evacuation of W7-X cryostat, cool-down of cold mass, electro-magnetic forces and self weight of leads. • The actual mechanical loads were reduced to simplify the experimental set-up. • The tests were carried out on mock-up flanges test assembly at ambient temperature and at 77 K. • The thermo-mechanical tests on W7-X current lead flanges validate the design and joints of these flanges to the leads. -- Abstract: Fourteen pieces of high temperature superconducting current leads (CL) arranged in seven pairs, will be installed on the outer vessel of Wendelstein 7-X (W7-X) stellarator. In order to support the CL, it is provided with two glass fiber reinforce plastic (GFRP) flanges, namely, the lower cryostat flange (CF) remaining at room temperature and upper radial flange (RF) at about 5 K. Both the flanges i.e. CF and RF experience high mechanical loads with respect to the CL, due to the evacuation of W7-X cryostat, cool-down of cold mass including the CL, electro-magnetic forces due to current and plasma operations and self weight of CL. In order to check the integrity of these flanges for such mechanical loads, thermo-mechanical tests were carried out on these flanges at room temperatures and at liquid nitrogen (LN2) temperatures. The details of test set-up, results and modeling are described in the paper

Fracture-mechanical results of non-destructive testing - function, goals, methods

International Nuclear Information System (INIS)

Herter, K.H.; Kockelmann, H.; Schuler, X.; Waidele, H.

2004-01-01

Non-destructive testing provides data for fracture-mechanical analyses, e.g. defect size and orientation. On the other hand, fracture-mechanical analyses may help to define criteria for non-destructive testing, e.g. sensitivity, inspection intervals and inspection sites. The criteria applied differ as a function of the safety relevance of a component. (orig.) [de

Stress corrosion cracks initiation of recrystallized Zircaloy-4 in iodine-methanol solutions

International Nuclear Information System (INIS)

Mozzani, N.

2013-01-01

During the pellet-cladding interaction, Zirconium-alloy fuel claddings might fail when subjected to incidental power transient in nuclear Pressurized Water Reactors, by Iodine-induced Stress Corrosion Cracking (I-SCC). This study deals with the intergranular initiation of I-SCC cracks in fully recrystallized Zircaloy-4, in methyl alcohol solution of iodine at room temperature, with the focus on critical mechanical parameters and iodine concentration. It was carried out with an approach mixing experiments and numerical simulations. An anisotropic and viscoplastic mechanical behavior model was established and validated over a wide range of loadings. With numerous constant elongation rate tensile tests and four points bending creep tests, the existence of a threshold iodine concentration I0 close to 10 -6 g.g -1 was highlighted, necessary to the occurrence of I-SCC damage, along with a transition concentration I1 close to 2.10 -4 g.g -1 . Above I1 the mechanism changes, leading to a sped up crack initiation and a loss of sensitivity towards mechanical parameters. The importance of concentration on parameters such as crack density, crack average length and intergranular and transgranular crack velocities was evidenced. Experimental results show that plastic strain is not required for I-SCC crack initiation, if the test time is long enough in the presence of stress. Its main influence is to rush the occurrence of cracking by creating initiation sites, by way of breaking the oxide layer and building up intergranular stress. Below I1, the critical strains at initiation show a substantial strain rate sensitivity. In this domain, a threshold stress of 100 MPa was found, well below the yield stress. Thanks to the combined use of notched specimens and numerical simulations, a strong protective effect of an increasing stress bi-axiality ratio was found, both in the elastic and plastic domains. Proton-irradiated samples, up to a dose of 2 dpa, were tested in the same conditions

CMOS-MEMS Test-Key for Extracting Wafer-Level Mechanical Properties

Directory of Open Access Journals (Sweden)

Pei-Zen Chang

2012-12-01

Full Text Available This paper develops the technologies of mechanical characterization of CMOS-MEMS devices, and presents a robust algorithm for extracting mechanical properties, such as Young’s modulus, and mean stress, through the external electrical circuit behavior of the micro test-key. An approximate analytical solution for the pull-in voltage of bridge-type test-key subjected to electrostatic load and initial stress is derived based on Euler’s beam model and the minimum energy method. Then one can use the aforesaid closed form solution of the pull-in voltage to extract the Young’s modulus and mean stress of the test structures. The test cases include the test-key fabricated by a TSMC 0.18 μm standard CMOS process, and the experimental results refer to Osterberg’s work on the pull-in voltage of single crystal silicone microbridges. The extracted material properties calculated by the present algorithm are valid. Besides, this paper also analyzes the robustness of this algorithm regarding the dimension effects of test-keys. This mechanical properties extracting method is expected to be applicable to the wafer-level testing in micro-device manufacture and compatible with the wafer-level testing in IC industry since the test process is non-destructive.

Self-Compacting Concrete Incorporating Micro-SiO2 and Acrylic Polymer

OpenAIRE

Heidari, Ali; Zabihi, Marzieh

2014-01-01

This study examined the effects of using acrylic polymer and micro-SiO2 in self-compacting concrete (SCC). Using these materials in SCC improves the characteristics of the concrete. Self-compacting samples with 1-2% of a polymer and 10% micro-SiO2 were made. In all cases, compressive strength, water absorption, and self-compacting tests were done. The results show that adding acrylic polymer and micro-SiO2 does not have a significant negative effect on the mechanical properties of self-compa...

Test methods for the dynamic mechanical properties of polymeric materials. Final report

Energy Technology Data Exchange (ETDEWEB)

Baker, G.K.

1980-06-01

Various test geometries and procedures for the dynamic mechanical analysis of polymers employing a mechanical spectrometer have been evaluated. The methods and materials included in this work are forced torsional pendulum testing of Kevlar/epoxy laminates and rigid urethane foams, oscillatory parallel plate testing to determine the kinetics of the cure of VCE with Hylene MP, oscillatory compressive testing of B-3223 cellular silicone, and oscillatory tensile testing of Silastic E and single Kevlar filaments. Fundamental dynamic mechanical properties, including the storage and loss moduli and loss tangent of the materials tested, were determined as a function of temperature and sometimes of frequency.

Hydrogen cracking and stress corrosion of pipeline steels. Contribution of the cracking mechanisms study to the understanding of the in-service damage and to the definition of a ranking test; Fissuration assistee par l'hydrogene et corrosion sous contrainte des aciers de pipelines. Apports de l'etude des mecanismes de fissuration a la comprehension de l'endommagement de service et a la definition d'un test de classification

Energy Technology Data Exchange (ETDEWEB)

Le Friant, D.

2000-12-19

This work is based on the study of the cracking of a French oil transmission pipeline protected by a cathodic protection system. The objective is to identify field parameters, which contribute to the cracks propagation, and to assess changes in the operating conditions, which could lead to a mitigation of the phenomenon. We have focused on the study of the micro-mechanisms by means of slow strain rate tests. Then, cyclic loading tests were carried out to investigate cracks propagation mechanisms. Smooth and pre-notched specimens were tested at free and cathodic potential. Hydrogen is responsible for crack advance through changes in the local steels properties. Such effects take place when two phenomenons occur: favourable conditions for hydrogen entry and, a localisation of hydrogen and its effects. In particular, we have shown the essential role of a dynamic loading in promoting hydrogen entry into the steel (especially at the very crack tip). At cathodic potential, hydrogen-related effects are exacerbated by the presence of MnS inclusions which leads to the initiation of internal cracks (HIC) and to a SOHIC-like crack morphology. At free potential, the lesser amount of available hydrogen give localisation-related effects a greater importance. Cracking is then related to a hydrogen-induced SCC mechanism. Three parameters are involved in the field cracking: operating pressure variations, period of over-protection and a sensitive steels microstructure (MnS). Cathodic protection appears to be the most efficient field parameter to mitigate the phenomenon: it requires a better control of the polarisation level. Finally, a ranking test is outlined from the study of the cracking mechanisms. (author)

Mechanical testing of hydrogels in cartilage tissue engineering: beyond the compressive modulus.

Science.gov (United States)

Xiao, Yinghua; Friis, Elizabeth A; Gehrke, Stevin H; Detamore, Michael S

2013-10-01

Injuries to articular cartilage result in significant pain to patients and high medical costs. Unfortunately, cartilage repair strategies have been notoriously unreliable and/or complex. Biomaterial-based tissue-engineering strategies offer great promise, including the use of hydrogels to regenerate articular cartilage. Mechanical integrity is arguably the most important functional outcome of engineered cartilage, although mechanical testing of hydrogel-based constructs to date has focused primarily on deformation rather than failure properties. In addition to deformation testing, as the field of cartilage tissue engineering matures, this community will benefit from the addition of mechanical failure testing to outcome analyses, given the crucial clinical importance of the success of engineered constructs. However, there is a tremendous disparity in the methods used to evaluate mechanical failure of hydrogels and articular cartilage. In an effort to bridge the gap in mechanical testing methods of articular cartilage and hydrogels in cartilage regeneration, this review classifies the different toughness measurements for each. The urgency for identifying the common ground between these two disparate fields is high, as mechanical failure is ready to stand alongside stiffness as a functional design requirement. In comparing toughness measurement methods between hydrogels and cartilage, we recommend that the best option for evaluating mechanical failure of hydrogel-based constructs for cartilage tissue engineering may be tensile testing based on the single edge notch test, in part because specimen preparation is more straightforward and a related American Society for Testing and Materials (ASTM) standard can be adopted in a fracture mechanics context.

Crack growth testing of cold worked stainless steel in a simulated PWR primary water environment to assess susceptibility to stress corrosion cracking

International Nuclear Information System (INIS)

Tice, D.R.; Stairmand, J.W.; Fairbrother, H.J.; Stock, A.

2007-01-01

Although austenitic stainless steels do not show a high degree of susceptibility to stress corrosion cracking (SCC) in PWR primary environments, there is limited evidence from laboratory testing that crack propagation may occur under some conditions for materials in a cold-worked condition. A test program is therefore underway to examine the factors influencing SCC propagation in good quality PWR primary coolant. Type 304 stainless steel was subjected to cold working by either rolling (at ambient or elevated temperature) or fatigue cycling, to produce a range of yield strengths. Compact tension specimens were fabricated from these materials and tested in simulated high temperature (250-300 o C) PWR primary coolant. It was observed that the degree of crack propagation was influenced by the degree of cold work, the crack growth orientation relative to the rolling direction and the method of working. (author)

Present status of the disk pressure tests for hydrogen embrittlement

International Nuclear Information System (INIS)

Fidelle, J.P.

1985-05-01

The Disk Pressure Tests (DPT) have been developed considerably theoretically and experimentally for Internal Hydrogen Embrittlement (IHE) e.g. Co, Ti, U alloys, for Environment Embrittlement due to H 2 , hydrogenated media such as water vapor, alcohol, machining fluids or liquid NH 3 . The range has been expanded considerably for pressure up to 300 MPa and temperature (-160 0 C to 1000 0 C). Very low strain rate -longer than a month- tests have been able to evidence embrittlement of FFC alloys where H diffusivity is low. Conversely for very oxidation - sensitive metals (e.g. Nb and Ta) effects may appear only at somewhat high rates. The relationship between dynamic (increasing stress) tests, static (delayed failure) and low-cycle fatigue tests has been determined. In a number of instances, including SCC, other techniques and even fracture mechanics have been compared to the DPT and proved at best equivalent and several times, less sensitive than a well conducted DPT. At extreme they could not reproduce the field service phenomenon whereas the DPT did and could also be applied satisfactorily to low yield stress materials. The main rupture aspects have been analyzed mechanically and organized in a rational and comprehensive chart based on 12,000 + tests over 150 + materials in different conditions. From the tests on a large number of metal systems, a theory of HE has been derived which accounts for the behavior of metals and alloys either embrittled and or hydrited. Finally comparison of HGE tests and service behavior of a large variety of materials and industrial equipments has made possible to specify acceptance criteria for industrial service

Performance Tests of a Mechanical Pump in Sodium Environment

Energy Technology Data Exchange (ETDEWEB)

Cho, Chungho; Kim, Jong-Man; Ko, Yung Joo; Kim, Byeongyeon; Cho, Youngil; Jung, Min-Hwan; Gam, Da-Young; Lee, Yong Bum; Jeong, Ji-Young; Kim, Jong-Bum [KAERI, Daejeon (Korea, Republic of)

2016-05-15

Water is often selected as a surrogate test fluid because it is not only cheap, easily available and easy to handle but also its important hydraulic properties (density and kinematic viscosity) are very similar to that of the sodium. Nevertheless, to ensure the performance, safety, and operability of major components before its installation in the SFR, a series of demonstration experiments of some components in sodium environment should be positively necessary. So, SFR NSSS System Design Division of Korea Atomic Energy Research Institute (KAERI) built various sodium experimental facilities, especially STELLA-1 in 2012. STELLA-1 (Sodium inTegral Effect test Loop for safety simuLation and Assessment) is a large-scale separated effect test facility for demonstrating the thermal-hydraulic performances of major components such as a Sodium-to-Sodium heat exchanger (DHX), Sodium-to-Air heat exchanger (AHX) of the decay heat removal system, and mechanical sodium pump of the primary heat transport system (PHTS). The mechanical pump in-sodium performance test was successfully performed with good reproducibility of the experiment and data to compare hydraulic characteristic of a mechanical pump in-water was collected. In effect of temperature variation on the pump pressure head, reduction of pump pressure head at 250℃ by 0.57% of that of 300℃ maybe the result of an increase in sodium viscosity by 13.6% according to operating temperature decrease by 50℃. Also, we confirmed that the more flywheel weight, the longer halving time and the more initial flow rate when the pump seized, the shorter halving time. The results of the mechanical pump performance test data in sodium environment will be used to compare with that of the in water environment after the evaluation of measurement uncertainty for tests.

Integrated approach for investigating the durability of self-consolidating concrete to sulfate attack

Science.gov (United States)

Bassuoni, Mohamed Tamer F.

The growing use of self-consolidating concrete (SCC) in various infrastructure applications exposed to sulfate-rich environments necessitates conducting comprehensive research to evaluate its durability to external sulfate attack. Since the reliability and adequacy of standard sulfate immersion tests have been questioned, the current thesis introduced an integrated testing approach for assessing the durability of a wide scope of SCC mixtures to external sulfate attack. This testing approach involved progressive levels of complexity from single to multiple damage processes. A new series of sulfate attack tests involving multiple field-like parameters and combined damage mechanisms (various cations, controlled pH, wetting-drying, partial immersion, freezing-thawing, and cyclic cold-hot conditions with or without sustained flexural loading) were designed to evaluate the performance (suitability) of the SCC mixtures under various sulfate attack exposure scenarios. The main mixture design variables of SCC included the type of binder (single, binary, ternary and quaternary), air-entrainment, sand-to-aggregate mass ratio and hybrid fibre reinforcement. The comprehensive database and knowledge obtained from this research were used to develop smart models (fuzzy and neuro-fuzzy inference systems) based on artificial-intelligence to evaluate and predict the performance of the SCC mixtures under various sulfate attack exposure regimes implemented in this study. In full immersion tests involving high concentration sodium and magnesium sulfate solutions with controlled pH, the low penetrability of SCC was responsible for the high durability of specimens. Ternary and quaternary cementitious systems with or without limestone materials provided a passivating layer, with or without acid neutralization capacity, which protected SCC from severe damage in the aggressive sulfuric acid and ammonium sulfate solutions. In contrast to conclusions drawn from the sodium sulfate immersion

Flow Induced segregation in full scale castings with SCC

DEFF Research Database (Denmark)

Thrane, Lars Nyholm; Stang, Henrik; Geiker, Mette Rica

2007-01-01

induced segregation is a major risk during casting and it is not yet clear how this phenomenon should be modelled. In this paper testing and numerical simulations of full-scale wall castings are compared. Two different SCCs and three different filling methods were applied resulting in different flow...... patterns during form filling. Results show that the flow patterns have a major influence on the risk of flow induced segregation and the surface finish of the hardened concrete. A hypothesis for the mechanism of flow induced segregation is put forth....

Ultrasound-based testing of tendon mechanical properties

DEFF Research Database (Denmark)

Seynnes, O R; Bojsen-Møller, J.; Albracht, K

2015-01-01

In the past 20 years, the use of ultrasound-based methods has become a standard approach to measure tendon mechanical properties in vivo. Yet the multitude of methodological approaches adopted by various research groups probably contribute to the large variability of reported values. The technique......, or signal synchronization; and 2) in physiological considerations related to the viscoelastic behavior or length measurements of tendons. Hence, the purpose of the present review is to assess and discuss the physiological and technical aspects connected to in vivo testing of tendon mechanical properties...

Test characteristics of high-resolution ultrasound in the preoperative assessment of margins of basal cell and squamous cell carcinoma in patients undergoing Mohs micrographic surgery.

Science.gov (United States)

Jambusaria-Pahlajani, Anokhi; Schmults, Chrysalyne D; Miller, Christopher J; Shin, Daniel; Williams, Jennifer; Kurd, Shanu K; Gelfand, Joel M

2009-01-01

Noninvasive techniques to assess subclinical spread of nonmelanoma skin cancer (NMSC) may improve surgical precision. High-resolution ultrasound has shown promise in evaluating the extent of NMSC. To determine the accuracy of high-resolution ultrasound to assess the margins of basal cell (BCC) and squamous cell carcinomas (SCC) before Mohs micrographic surgery (MMS). We enrolled 100 patients with invasive SCC or BCC. Before the first stage of MMS, a Mohs surgeon delineated the intended surgical margin. Subsequently, a trained ultrasound technologist independently evaluated disease extent using the EPISCAN I-200 to evaluate tumor extent beyond this margin. The accuracy of high-resolution ultrasound was subsequently tested by comparison with pathology from frozen sections. The test characteristics of the high-resolution ultrasound were sensitivity=32%, specificity=88%, positive predictive value=47%, and negative predictive value=79%. Subgroup analyses demonstrated better test characteristics for tumors larger than the median (area>1.74 cm(2)). Qualitative analyses showed that high-resolution ultrasound was less likely to identify extension from tumors with subtle areas of extension, such as small foci of dermal invasion from infiltrative SCC and micronodular BCC. High-resolution ultrasound requires additional refinements to improve the preoperative determination of tumor extent before surgical treatment of NMSC.

Corrosion behaviour of AISI 304 stainless steel subjected to massive laser shock peening impacts with different pulse energies

International Nuclear Information System (INIS)

Lu, J.Z.; Qi, H.; Luo, K.Y.; Luo, M.; Cheng, X.N.

2014-01-01

Highlights: •Laser shock peening caused an obvious increase of corrosion resistance of 304 steel. •Corrosion resistance of stainless steel increased with increasing pulse energy. •Mechanism of laser shock peening on corrosion behaviour was also entirely determined. -- Abstract: Effects of massive laser shock peening (LSP) impacts with different pulse energies on ultimate tensile strength (UTS), stress corrosion cracking (SCC) susceptibility, fracture appearance and electrochemical corrosion resistance of AISI 304 stainless steel were investigated by slow strain rate test, potentiodynamic polarisation test and scanning electron microscope observation. The influence mechanism of massive LSP impacts with different pulse energies on corrosion behaviour was also determined. Results showed that massive LSP impacts effectively caused a significant improvement on UTS, SCC resistance, and electrochemical corrosion resistance of AISI 304 stainless steel. Increased pulse energy can also gradually improve its corrosion resistance

Mechanism of testosterone deficiency in the transgenic sickle cell mouse.

Directory of Open Access Journals (Sweden)

Biljana Musicki

Full Text Available Testosterone deficiency is associated with sickle cell disease (SCD, but its underlying mechanism is not known. We investigated the possible occurrence and mechanism of testosterone deficiency in a mouse model of human SCD. Transgenic sickle male mice (Sickle exhibited decreased serum and intratesticular testosterone and increased luteinizing hormone (LH levels compared with wild type (WT mice, indicating primary hypogonadism in Sickle mice. LH-, dbcAMP-, and pregnenolone- (but not 22-hydroxycholesterol- stimulated testosterone production by Leydig cells isolated from the Sickle mouse testis was decreased compared to that of WT mice, implying defective Leydig cell steroidogenesis. There also was reduced protein expression of steroidogenic acute regulatory protein (STAR, but not cholesterol side-chain cleavage enzyme (P450scc, in the Sickle mouse testis. These data suggest that the capacity of P450scc to support testosterone production may be limited by the supply of cholesterol to the mitochondria in Sickle mice. The sickle mouse testis exhibited upregulated NADPH oxidase subunit gp91phox and increased oxidative stress, measured as 4-hydroxy-2-nonenal, and unchanged protein expression of an antioxidant glutathione peroxidase-1. Mice heterozygous for the human sickle globin (Hemi exhibited intermediate hypogonadal changes between those of WT and Sickle mice. These results demonstrate that testosterone deficiency occurs in Sickle mice, mimicking the human condition. The defects in the Leydig cell steroidogenic pathway in Sickle mice, mainly due to reduced availability of cholesterol for testosterone production, may be related to NADPH oxidase-derived oxidative stress. Our findings suggest that targeting testicular oxidative stress or steroidogenesis mechanisms in SCD offers a potential treatment for improving phenotypic changes associated with testosterone deficiency in this disease.

Stress corrosion cracking in 17-4PH and 17-7PH stainless steels in NaCl and NaOH (20%) a 90 deg C

International Nuclear Information System (INIS)

Gaona-Tiburcio, C.; Almeraya-Calderon, F.; Martinez-Villafane, A.

2000-01-01

One of the problems that affects to the electric industry is the not programmed stoppages in the power plants, due to the failure of any main component: boiler, turbine and generator. In the turbine, the combined action of a corrosive agent (humid polluted vapor) and a mechanical effort, generally will result in Stress Corrosion Cracking (SCC). In this work the SCC susceptibility of the precipitation hardening stainless steels 17-4PH and 17-17PH, thoroughly used in steam turbine blades of power stations is analyzed. The specimens were tested in the presence of NaCl and NaOH(20%) to 90 deg C and different pH. The CERT test (Constant Extension Rate Test) was used, at 10''-6 s''-1, supplementing it with electrochemical noise, the aim was to identify the conditions of maximum susceptibility and the performance of the studied materials. The fractographic analysis revealed ductile and brittle fracture. Intergranular cracking, characteristic of the anodic dissolution mechanisms of the materials was observed. Nevertheless, the main mechanism responsible the failure was hydrogen embrittlement. (Author) 6 refs

Mechanical Characterization and Corrosion Testing of X608 Al Alloy

Energy Technology Data Exchange (ETDEWEB)

Prabhakaran, Ramprashad; Choi, Jung-Pyung; Stephens, Elizabeth V.; Catalini, David; Lavender, Curt A.; Rohatgi, Aashish

2016-02-07

This paper describes the mechanical characterization and corrosion testing of X608 Al alloy that is being considered for A-pillar covers for heavy-duty truck applications. Recently, PNNL developed a thermo-mechanical process to stamp A-pillar covers at room temperature using this alloy, and the full-size prototype was successfully stamped by a tier-1 supplier. This study was conducted to obtain additional important information related to the newly developed forming process, and to further improve its mechanical properties. The solutionization temperature, pre-strain and paint-bake heat-treatment were found to influence the alloy’s fabricability and mechanical properties. Natural aging effect on the formability was investigated by limiting dome height (LDH) tests. Preliminary corrosion experiments showed that the employed thermo-mechanical treatments did not significantly affect the corrosion behavior of Al X608.

UKAEA mechanical test work in sodium

International Nuclear Information System (INIS)

Wood, D.S.

1977-01-01

The main aim of the UKAEA work is to perform mechanical tests in high quality sodium, and on the basis of relatively long term tests to establish whether factors need to be applied to the air data for the design and assessment of components which will have to operate in sodium for up to 30 years. Most of the tests will be performed in sodium containing 5-10 ppm O 2 and ∼ 1 ppm C with a flow rate over the specimen surface of 3m/sec. Some work is also planned to establish the effect of changes in oxygen level up to 30 ppm on the properties and carburization studies will also be performed. Thin work has been in progress on a limited scale for 2-3 years but is now increasing in magnitude to meet the programme requirements. The materials under test include Type 316 steel and 9% Cr steel with most emphasis being placed on the austenitic steel. From the very limited fatigue and stress rupture tests so far performed on Type 316 steel there is no evidence to suggest that high purity sodium may be detrimental. Longer term tests are necessary however to confirm this finding which is based on results from relatively short term tests. Tests are also necessary in less pure sodium

Test characteristics of milk amyloid A ELISA, somatic cell count, and bacteriological culture for detection of intramammary pathogens that cause subclinical mastitis.

Science.gov (United States)

Jaeger, S; Virchow, F; Torgerson, P R; Bischoff, M; Biner, B; Hartnack, S; Rüegg, S R

2017-09-01

Bovine mastitis is an important disease in the dairy industry, causing economic losses as a result of withheld milk and treatment costs. Several studies have suggested milk amyloid A (MAA) as a promising biomarker in the diagnosis of mastitis. In the absence of a gold standard for diagnosis of subclinical mastitis, we estimated the diagnostic test accuracy of a commercial MAA-ELISA, somatic cell count (SCC), and bacteriological culture using Bayesian latent class modeling. We divided intramammary infections into 2 classes: those caused by major pathogens (e.g., Escherichia coli, Staphylococcus aureus, streptococci, and lacto-/enterococci) and those caused by all pathogens (major pathogens plus Corynebacterium bovis, coagulase-negative staphylococci, Bacillus spp., Streptomyces spp.). We applied the 3 diagnostic tests to all samples. Of 433 composite milk samples included in this study, 275 (63.5%) contained at least 1 colony of any bacterial species; of those, 56 contained major pathogens and 219 contained minor pathogens. The remaining 158 samples (36.5%) were sterile. We determined 2 different thresholds for the MAA-ELISA using Bayesian latent class modeling: 3.9 µg/mL to detect mastitis caused by major pathogens and 1.6 µg/mL to detect mastitis caused by all pathogens. The optimal SCC threshold for identification of subclinical mastitis was 150,000 cells/mL; this threshold led to higher specificity (Sp) than 100,000 cells/mL. Test accuracy for major-pathogen intramammary infections was as follows: SCC, sensitivity (Se) 92.6% and Sp 72.9%; MAA-ELISA, Se 81.4% and Sp 93.4%; bacteriological culture, Se 23.8% and Sp 95.2%. Test accuracy for all-pathogen intramammary infections was as follows: SCC, sensitivity 90.3% and Sp 71.8%; MAA-ELISA, Se 88.0% and Sp 65.2%; bacteriological culture, Se 83.8% and Sp 54.8%. We suggest the use of SCC and MAA-ELISA as a combined screening procedure for situations such as a Staphylococcus aureus control program. With Bayesian

Effect of Ni and Cr on IGSCC growth rate of Ni-Cr-Fe alloys in PWR primary water

International Nuclear Information System (INIS)

Arioka, K.; Yamada, T.; Aoki, M.; Miyamoto, T.

2015-01-01

surface attack seems to play some role on SCC growth. Most important engineering meaning of the complicated temperature dependence with peak is that the mechanism of IGSCC growth at higher temperature is different from that at operating temperature. Furthermore, the order of SCC resistance at higher temperature is not the same at operating temperature. This means that we should pay careful attention to assess SCC from accelerated testing at higher temperature. (authors)

Diseño de un sistema administrativo contable aplicable a la empresa Centro Artesanal Niño Jesús S.C.C.

OpenAIRE

Posso García, Carlos Patricio

2006-01-01

El Sistema Administrativo Contable es el pilar de toda organización para poder desarrollar adecuadamente sus actividades, estableciendo responsabilidades a los encargados de las todas las áreas, medidas de seguridad y control. Diseñar un modelo de un SISTEMA ADMINISTRATIVO-CONTABLE para la empresa CENTRO ARTESANAL NIÑO JESÚS S.C.C. permitirá contar con una oportuna, completa y exacta información de los resultados financieros de la Empresa en su conjunto; así como mejorar los procesos ad...

Development and validation of an achievement test in introductory quantum mechanics: The Quantum Mechanics Visualization Instrument (QMVI)

Science.gov (United States)

Cataloglu, Erdat

The purpose of this study was to construct a valid and reliable multiple-choice achievement test to assess students' understanding of core concepts of introductory quantum mechanics. Development of the Quantum Mechanics Visualization Instrument (QMVI) occurred across four successive semesters in 1999--2001. During this time 213 undergraduate and graduate students attending the Pennsylvania State University (PSU) at University Park and Arizona State University (ASU) participated in this development and validation study. Participating students were enrolled in four distinct groups of courses: Modern Physics, Undergraduate Quantum Mechanics, Graduate Quantum Mechanics, and Chemistry Quantum Mechanics. Expert panels of professors of physics experienced in teaching quantum mechanics courses and graduate students in physics and science education established the core content and assisted in the validating of successive versions of the 24-question QMVI. Instrument development was guided by procedures outlined in the Standards for Educational and Psychological Testing (AERA-APA-NCME, 1999). Data gathered in this study provided information used in the development of successive versions of the QMVI. Data gathered in the final phase of administration of the QMVI also provided evidence that the intended score interpretation of the QMVI achievement test is valid and reliable. A moderate positive correlation coefficient of 0.49 was observed between the students' QMVI scores and their confidence levels. Analyses of variance indicated that students' scores in Graduate Quantum Mechanics and Undergraduate Quantum Mechanics courses were significantly higher than the mean scores of students in Modern Physics and Chemistry Quantum Mechanics courses (p important factor for students in acquiring a successful understanding of quantum mechanics.

Test characteristics of high frequency ultrasound in the pre-operative assessment of margins of basal cell and squamous cell carcinoma in patients undergoing Mohs micrographic surgery

Science.gov (United States)

Jambusaria-Pahlajani, Anokhi; Schmults, Chrysalyne D.; Miller, Christopher J.; Shin, Daniel; Williams, Jennifer; Kurd, Shanu K; Gelfand, Joel M.

2015-01-01

Background Non-invasive techniques to assess subclinical spread of non-melanoma skin cancer (NMSC) may improve surgical precision. High frequency ultrasound (HIFU) has shown promise to evaluate the extent of NMSC. Objective To determine the accuracy of HIFU to assess the margins of basal cell (BCC) and squamous cell carcinomas (SCC) prior to Mohs micrographic surgery (MMS). Methods We enrolled 100 patients with invasive SCC or BCC. Prior to the first stage of MMS, a Mohs surgeon delineated the intended surgical margin. Subsequently, a trained ultrasound technologist independently evaluated disease extent using the EPISCAN I-200 to evaluate tumor extent beyond this margin. The accuracy of HIFU was subsequently tested by comparison to pathology from frozen sections. Results The test characteristics of the ultrasound were sensitivity= 32%, specificity= 88%, positive predictive value= 47%, and negative predictive value=79%. Subgroup analyses demonstrated improved test characteristics for tumors larger than the median (area >1.74 cm2). Qualitative analyses showed that HIFU was less likely to identify extension from tumors with subtle areas of extension, such as small foci of dermal invasion from infiltrative SCC and micronodular BCC. Conclusions HIFU requires additional refinements to improve the preoperative determination of tumor extent prior to surgical treatment of NMSC. PMID:19018815

TESTING METHODS FOR MECHANICALLY IMPROVED SOILS: RELIABILITY AND VALIDITY

Directory of Open Access Journals (Sweden)

Ana Petkovšek

2017-10-01

Full Text Available A possibility of in-situ mechanical improvement for reducing the liquefaction potential of silty sands was investigated by using three different techniques: Vibratory Roller Compaction, Rapid Impact Compaction (RIC and Soil Mixing. Material properties at all test sites were investigated before and after improvement with the laboratory and the in situ tests (CPT, SDMT, DPSH B, static and dynamic load plate test, geohydraulic tests. Correlation between the results obtained by different test methods gave inconclusive answers.

Stress corrosion cracking behavior of zircaloy-2 in iodine environment

International Nuclear Information System (INIS)

Ikeda, Seiichi

1983-01-01

The effects of strain rates, iodine partial pressure and testing temperature on SCC behavior of zircaloy-2 in iodine environment were studied by means of slow strain rate technique (SSRT). SCC behavior of recrystallized specimens in iodine environment was remarkably influenced by the testing temperatures, and the susceptibility to SCC of specimens tested at 623 K was higher than that at 573 K. The susceptibility to SCC of recrystallized specimens increased with increasing iodine partial pressure at the lower strain rates of 4.2 x 10 -6 s -1 and 8.3 x 10 -7 s -1 . Cold worked specimens indicate no SCC failure in iodine environment regardless of strain rates, although those were tested only at 573 K. Fractographic observation revealed that SCC features of recrystallized specimens can be classified into two groups. One group, mostly specimens tested at 573 K, are characterized by the fact that cracks are initiated from corrosion pits. The other group are characterized by transgranuler SCC in the absence of pitting. This type of crack is found on specimens tested in environments containing more than 570 Pa iodine and seems to be produced by iodine embrittlement. (author)

Mechanisms Engineering Test Loop - Phase 1 Status Report

Energy Technology Data Exchange (ETDEWEB)

Kultgen, D. [Argonne National Lab. (ANL), Argonne, IL (United States); Grandy, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Hvasta, M. [Argonne National Lab. (ANL), Argonne, IL (United States); Lisowski, D. [Argonne National Lab. (ANL), Argonne, IL (United States); Toter, W. [Argonne National Lab. (ANL), Argonne, IL (United States); Borowski, A. [Argonne National Lab. (ANL), Argonne, IL (United States)

2016-09-01

This report documents the current status of the Mechanisms Engineering Test Loop (METL) as of the end of FY2016. Currently, METL is in Phase I of its design and construction. Once operational, the METL facility will test small to intermediate-scale components and systems in order to develop advanced liquid metal technologies. Testing different components in METL is essential for the future of advanced fast reactors as it will provide invaluable performance data and reduce the risk of failures during plant operation.

Mechanical design and testing of a hot-gas turbine on a test facility

International Nuclear Information System (INIS)

Staude, R.

1981-01-01

Advanced calculation methods and specific solutions for any particular problem are basic requirements for the mechanical design of hot-gas components for gas turbines. The mechanical design contributes a great deal to the smooth running and operational reliability and thus to the quality of the machine. By reference to an expander, the present paper discusses the strength of hot components, such as the casing and the rotor, for both stationary and transient temperature distribution. Mechanical testing under hot-gas conditions fully confirmed the reliability of the rating and design of the hot-gas turbines supplied by M:A.N.-GHH STERKRADE. (orig.) [de

Space Mechanisms Lessons Learned and Accelerated Testing Studies

Science.gov (United States)

Fusaro, Robert L.

1997-01-01

A number of mechanism (mechanical moving component) failures and anomalies have recently occurred on satellites. In addition, more demanding operating and life requirements have caused mechanism failures or anomalies to occur even before some satellites were launched (e.g., during the qualification testing of GOES-NEXT, CERES, and the Space Station Freedom Beta Joint Gimbal). For these reasons, it is imperative to determine which mechanisms worked in the past and which have failed so that the best selection of mechanically moving components can be made for future satellites. It is also important to know where the problem areas are so that timely decisions can be made on the initiation of research to develop future needed technology. To chronicle the life and performance characteristics of mechanisms operating in a space environment, a Space Mechanisms Lessons Learned Study was conducted. The work was conducted by the NASA Lewis Research Center and by Mechanical Technologies Inc. (MTI) under contract NAS3-27086. The expectation of the study was to capture and retrieve information relating to the life and performance of mechanisms operating in the space environment to determine what components had operated successfully and what components had produced anomalies.

A Proposed Molecular Mechanism of High-Dose Vitamin D3 Supplementation in Prevention and Treatment of Preeclampsia

Directory of Open Access Journals (Sweden)

Piotr Zabul

2015-06-01

Full Text Available A randomized prospective clinical study performed on a group of 74 pregnant women (43 presenting with severe preeclampsia proved that urinary levels of 15-F2t-isoprostane were significantly higher in preeclamptic patients relative to the control (3.05 vs. 2.00 ng/mg creatinine. Surprisingly enough, plasma levels of 25-hydroxyvitamin D3 in both study groups were below the clinical reference range with no significant difference between the groups. In vitro study performed on isolated placental mitochondria and placental cell line showed that suicidal self-oxidation of cytochrome P450scc may lead to structural disintegration of heme, potentially contributing to enhancement of oxidative stress phenomena in the course of preeclampsia. As placental cytochrome P450scc pleiotropic activity is implicated in the metabolism of free radical mediated arachidonic acid derivatives as well as multiple Vitamin D3 hydroxylations and progesterone synthesis, we propose that Vitamin D3 might act as a competitive inhibitor of placental cytochrome P450scc preventing the production of lipid peroxides or excess progesterone synthesis, both of which may contribute to the etiopathogenesis of preeclampsia. The proposed molecular mechanism is in accord with the preliminary clinical observations on the surprisingly high efficacy of high-dose Vitamin D3 supplementation in prevention and treatment of preeclampsia.

Three-dimensional study of grain boundary engineering effects on intergranular stress corrosion cracking of 316 stainless steel in high temperature water

Science.gov (United States)

Liu, Tingguang; Xia, Shuang; Bai, Qin; Zhou, Bangxin; Zhang, Lefu; Lu, Yonghao; Shoji, Tetsuo

2018-01-01

The intergranular cracks and grain boundary (GB) network of a GB-engineered 316 stainless steel after stress corrosion cracking (SCC) test in high temperature high pressure water of reactor environment were investigated by two-dimensional and three-dimensional (3D) characterization in order to expose the mechanism that GB-engineering mitigates intergranular SCC. The 3D microstructure shown that the essential characteristic of the GB-engineered microstructure is formation of many large twin-boundaries as a result of multiple-twinning, which results in the formation of large grain-clusters. The large grain-clusters played a key role to the improvement of intergranular SCC resistance by GB-engineering. The main intergranular cracks propagated in a zigzag along the outer boundaries of these large grain-clusters because all inner boundaries of the grain-clusters were twin-boundaries (∑3) or twin-related boundaries (∑3n) which had much lower susceptibility to SCC than random boundaries. These large grain-clusters had tree-ring-shaped topology structure and very complex morphology. They got tangled so that difficult to be separated during SCC, resulting in some large crack-bridges retained in the crack surface.

14 CFR 27.923 - Rotor drive system and control mechanism tests.

Science.gov (United States)

2010-01-01

... the position that will give maximum longitudinal cyclic pitch change to simulate forward flight. The... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Rotor drive system and control mechanism....923 Rotor drive system and control mechanism tests. (a) Each part tested as prescribed in this section...

Mechanical Testing of Carbon Based Woven Thermal Protection Materials

Science.gov (United States)

Pham, John; Agrawal, Parul; Arnold, James O.; Peterson, Keith; Venkatapathy, Ethiraj

2013-01-01

Three Dimensional Woven thermal protection system (TPS) materials are one of the enabling technologies for mechanically deployable hypersonic decelerator systems. These materials have been shown capable of serving a dual purpose as TPS and as structural load bearing members during entry and descent operations. In order to ensure successful structural performance, it is important to characterize the mechanical properties of these materials prior to and post exposure to entry-like heating conditions. This research focuses on the changes in load bearing capacity of woven TPS materials after being subjected to arcjet simulations of entry heating. Preliminary testing of arcjet tested materials [1] has shown a mechanical degradation. However, their residual strength is significantly more than the requirements for a mission to Venus [2]. A systematic investigation at the macro and microstructural scales is reported here to explore the potential causes of this degradation. The effects of heating on the sizing (an epoxy resin coating used to reduce friction and wear during fiber handling) are discussed as one of the possible causes for the decrease in mechanical properties. This investigation also provides valuable guidelines for margin policies for future mechanically deployable entry systems.

Electrochemical studies on stress corrosion cracking of incoloy-800 in caustic solution. Part II: Precracking samples

Directory of Open Access Journals (Sweden)

Dinu Alice

2006-01-01

Full Text Available Stress corrosion cracking (SCC in a caustic medium may affect the secondary circuit tubing of a CANDU NPP cooled with river water, due to an accidental formation of a concentrated alkaline environment in the areas with restricted circulation, as a result of a leakage of cooling water from the condenser. To evaluate the susceptibility of Incoloy-800 (used to manufacture steam generator tubes for CANDU NPP to SCC, some accelerated corrosion tests were conducted in an alkaline solution (10% NaOH, pH = 13. These experiments were performed at ambient temperature and 85 °C. We used the potentiodynamic method and the potentiostatic method, simultaneously monitoring the variation of the open circuit potential during a time period (E corr/time curve. The C-ring method was used to stress the samples. In order to create stress concentrations, mechanical precracks with a depth of 100 or 250 μm were made on the outer side of the C-rings. Experimental results showed that the stressed samples were more susceptible to SCC than the unstressed samples whereas the increase in temperature and crack depth lead to an increase in SCC susceptibility. Incipient micro cracks of a depth of 30 μm were detected in the area of the highest peak of the mechanical precrack.

Standard test method for determining susceptibility to stress-corrosion cracking of 2XXX and 7XXX Aluminum alloy products

CERN Document Server

American Society for Testing and Materials. Philadelphia

1998-01-01

1.1 This test method covers a uniform procedure for characterizing the resistance to stress-corrosion cracking (SCC) of high-strength aluminum alloy wrought products for the guidance of those who perform stress-corrosion tests, for those who prepare stress-corrosion specifications, and for materials engineers. 1.2 This test method covers method of sampling, type of specimen, specimen preparation, test environment, and method of exposure for determining the susceptibility to SCC of 2XXX (with 1.8 to 7.0 % copper) and 7XXX (with 0.4 to 2.8 % copper) aluminum alloy products, particularly when stressed in the short-transverse direction relative to the grain structure. 1.3 The values stated in SI units are to be regarded as standard. The inch-pound units in parentheses are provided for information. 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 de...

Development of interim test methods and procedures for determining the performance of small photovoltaic systems

Energy Technology Data Exchange (ETDEWEB)

McNutt, P.; Kroposki, B.; Hansen, R.; Algra, K.; DeBlasio, R. [National Renewable Energy Lab., Golden, CO (United States)

1998-09-01

The National Renewable Energy Laboratory (NREL) is developing tests and procedures that will determine if the configuration of a small photovoltaic (PV) system is suitable for its intended use, and if the system will perform as specified. An overview of these procedures is presented in this paper. Development of standard test procedures will allow designers, manufacturers, system integrators, users, and independent laboratories to assess the performance of PV systems under outdoor prevailing conditions. An NREL Technical Report detailing the procedures is under way, and the IEEE Standards Coordinating Committee 21 (SCC21) has established a project on this subject. The work will be submitted to the IEEE SCC21 and International Electrotechnical Commission Technical Committee 82 (IEC TC82) for consideration as a consensus standard. Certification bodies such as PowerMark and PV Global Approval Program (PVGAP) may adopt the IEC and IEEE documents when testing systems. Developing standardized test methods and procedures at NREL to evaluate the outdoor performance of PV systems will encourage product quality and promote PV standards development. Standardized tests will assure people that PV systems will perform as specified for their intended applications. As confidence in PV systems increases, the successful commercialization of PV will grow internationally.

Evaluation on mechanical and corrosion properties of steam generator tubing materials

International Nuclear Information System (INIS)

Kim, In Sup; Lee, Byong Whi; Lee, Sang Kyu; Lee, Young Ho; Kim, Jun Whan; Lee, Ju Seok; Kwon, Hyuk Sang; Kim, Su Jung

1998-06-01

Steam generator is one of the major components of nuclear reactor pressure boundary. It's main function os transferring heat which generated in the reactor to turbine generator through steam generator tube. In these days, steam generator tubing materials of operating plant are used Inconel 600 alloys. But according to the operation time, there are many degradation phenomena which included mechanical damage due to flow induced vibration and corrosion damage due to PWSCC, IGA/SCC and pitting etc. Recently Inconel 690 alloys are selected as new and replacement steam generator tubes for domestic nuclear power plant. But there are few study about mechanical and corrosion properties of Inconel 600 and 690. The objectives of this study is to evaluate and compare mechanical and corrosion propertied of steam generator tube materials

Evaluation on mechanical and corrosion properties of steam generator tubing materials

Energy Technology Data Exchange (ETDEWEB)

Kim, In Sup; Lee, Byong Whi; Lee, Sang Kyu; Lee, Young Ho; Kim, Jun Whan; Lee, Ju Seok; Kwon, Hyuk Sang; Kim, Su Jung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

1998-06-15

Steam generator is one of the major components of nuclear reactor pressure boundary. It's main function os transferring heat which generated in the reactor to turbine generator through steam generator tube. In these days, steam generator tubing materials of operating plant are used Inconel 600 alloys. But according to the operation time, there are many degradation phenomena which included mechanical damage due to flow induced vibration and corrosion damage due to PWSCC, IGA/SCC and pitting etc. Recently Inconel 690 alloys are selected as new and replacement steam generator tubes for domestic nuclear power plant. But there are few study about mechanical and corrosion properties of Inconel 600 and 690. The objectives of this study is to evaluate and compare mechanical and corrosion propertied of steam generator tube materials.

The use of non-destructive tests to estimate Self-compacting concrete compressive strength

Directory of Open Access Journals (Sweden)

Djamila Boukhelkhal

2018-01-01

Full Text Available Until now, there are few studies on the effect of mineral admixtures on correlation between compressive strength and ultrasonic pulse velocity for concrete. The aim of this work is to study the effect of mineral admixture available in Algeria such as limestone powder, granulated slag and natural pozzolana on the correlation between compressive strength and corresponding ultrasonic pulse velocity for self-compacting concrete (SCC. Compressive strength and ultrasonic pulse velocity (UPV were determined for four different SCC (with and without mineral admixture at the 3, 7, 28 and 90 day curing period. The results of this study showed that it is possible to develop a good correlation relationship between the compressive strength and the corresponding ultrasonic pulse velocity for all SCC studied in this research and all the relationships had exponential form. However, constants were different for each mineral admixture type; where, the best correlation was found in the case of SCC with granulated slag (R2 = 0.85. Unlike the SCC with pozzolana, which have the lowest correlation coefficient (R2 = 0.69.

Modification and upgradation of corrosion fatigue testing system

International Nuclear Information System (INIS)

Farooq, A.; Qamar, R.

2006-08-01

Stress Corrosion Cracking (SCC) and Corrosion Fatigue (CF) are important tests which are performed to check the integrity of structural materials operating in different environments, such as nuclear power system, steam and gas turbines, aircraft marine structure, pipelines and bridges. To establish the environmental testing facility on laboratory scale, NMD acquired a computerized (286 Based PC) electromechanical testing machine from M/S CorTest, USA. This machine was commissioned at NMD in 1989. Since then it has been utilized to test and qualify the materials provided by different establishments of PAEC for SCC and CF behavior. However, in October 2004, computer attached to the machine was corrupted and became out of order. Users were handicapped because there was no any alternate system i.e. Manual control tower to operate the machine. Then users approached to Computer Division to investigate the malfunctioning at the computer. Therefore, upon complete checkup of system, it was diagnosed that there was a serious problem in the hard disk and mother board of the computer. Much difficulty was faced in retrieving the application software from the obsolete 286 computer system. Then the basic aim was to replace the old computer with Pentium System. But with Pentium system application software was not working. Since we have already recovered full application software package including source programs, so all the seventeen programs has been thoroughly studied. Four programs had to be modified according to the new hardware. Now the new Pentium system with modified software has been interfaced with the machine. Machine was tested for the both types of above mentioned tests and compared with previous results. The performance of machine was confirmed satisfactory on the new setup. (author)

Pimonidazole labelling and response to fractionated irradiation of five human squamous cell carcinoma (hSCC) lines in nude mice: The need for a multivariate approach in biomarker studies

International Nuclear Information System (INIS)

Yaromina, Ala; Zips, Daniel; Thames, Howard D.; Eicheler, Wolfgang; Krause, Mechthild; Rosner, Andrea; Haase, Michael; Petersen, Cordula; Raleigh, James A.; Quennet, Verena; Walenta, Stefan; Mueller-Klieser, Wolfgang; Baumann, Michael

2006-01-01

Objective: To investigate the influence on local control after fractionated radiotherapy of hypoxia measured in unirradiated tumours using the hypoxic marker Pimonidazole, using multivariate approaches. Material and methods: Five human squamous cell carcinoma lines (FaDu, UT-SCC-15, UT-SCC-14, XF354, and UT-SCC-5) were transplanted subcutaneously into the right hind-leg of NMRI nude mice. Histological material was collected from 60 unirradiated tumours after injection of Pimonidazole. The relative hypoxic area within the viable tumour area (Pimonidazole hypoxic fraction, pHF) was determined in seven serial 10 μm cross-sections per tumour by fluorescence microscopy and computerized image analysis. Local tumour control was evaluated in a total of 399 irradiated tumours at 120 days after 30 fractions given within 6 weeks with total doses between 30 and 115 Gy. Results: Tumour lines showed pronounced heterogeneity in both pHF and TCD 5 . Mean pHF values varied between 5% and 37%, TCD 5 values between 47 and 130 Gy. A Cox Proportional Hazards model of time to recurrence with two covariates, dose and pHF, yielded significant contributions of both parameters on local control (p < 0.005) but violated the proportional hazards assumption, suggesting that other factors also influence tumour control. Introduction of histological grade as an example of a confounding factor into the model improved the fit significantly. Local control rates decreased with increasing pHF and this effect was more pronounced at higher doses. Conclusions: This study confirms that tumour hypoxia measured using Pimonidazole in untreated tumours is a significant determinant of local control after fractionated irradiation. The data support the use of multivariate approaches for the evaluation of a single prognostic biomarker such as Pimonidazole, and more generally, suggest that they are required to establish accurate prognostic factors for tumour response

Sierra/SolidMechanics 4.48 Verification Tests Manual.

Energy Technology Data Exchange (ETDEWEB)

Plews, Julia A.; Crane, Nathan K; de Frias, Gabriel Jose; Le, San; Littlewood, David John; Merewether, Mark Thomas; Mosby, Matthew David; Pierson, Kendall H.; Porter, Vicki L.; Shelton, Timothy; Thomas, Jesse David; Tupek, Michael R.; Veilleux, Michael; Xavier, Patrick G.

2018-03-01

Presented in this document is a small portion of the tests that exist in the Sierra / SolidMechanics (Sierra / SM) verification test suite. Most of these tests are run nightly with the Sierra / SM code suite, and the results of the test are checked versus the correct analytical result. For each of the tests presented in this document, the test setup, a description of the analytic solution, and comparison of the Sierra / SM code results to the analytic solution is provided. Mesh convergence is also checked on a nightly basis for several of these tests. This document can be used to confirm that a given code capability is verified or referenced as a compilation of example problems. Additional example problems are provided in the Sierra / SM Example Problems Manual. Note, many other verification tests exist in the Sierra / SM test suite, but have not yet been included in this manual.

Influence of microstructure on stress corrosion cracking susceptibility of alloys 600 and 690 in primary water of pressurized water reactors

International Nuclear Information System (INIS)

Kergaravat, J.F.

1996-01-01

The mechanism(s) responsible for the stress corrosion cracking (SCC) of Alloy 600 steam generator tubes of pressurized water reactors remain misunderstood in spite of numerous studies on the subject. This failure mode presents several experimental similarities with intergranular creep fracture of austenitic stainless steels. As far as intergranular creep fracture is concerned, grain boundary sliding (GBS) was proved to favor failure. The aim of this work is to check the role played by GBS during SCC. It takes into account chemical (chromium content) and microstructural parameters (grain size, precipitation distribution and density). Therefore, to get a complete set of micro-structurally different samples, we have prepared solution annealed specimens (1100 deg C, 20 min., water quenched) from industrial tubes of Alloys 600 and 690. Each specimen was crept at 500 deg C (400 MPa), 430 deg C (425 MPa) and 360 deg C (475 MPa). Before testing, every sample were engraved with a 7 μm wide fiducial grid. This grid has allowed us to measure GBS after creep testing. GBS was observed for industrial and solution annealed samples for the three testing temperatures. GBS amplitude depends'on chromium content: for micro-structurally identical specimens, Alloy 600 exhibits more GB strain than Alloy 690. It also strongly depends on grain boundary precipitation characteristics: carbide free boundaries slide more easily. During in situ straining experiments performed in a transmission electronic microscope, GBS was evidenced at 320 deg C for Alloy 600 industrial samples. It consists in grain boundary dislocation motion in the interface plane. These dislocations originate from perfect dislocations gliding in the grain interior, encountering grain boundary and spreading in it. Metallic intergranular carbides provide strong obstacles to GBS so stress enhancements arise against them. These stress enhancements are released by micro-twin emission. Constant extension rate tensile tests were

Bandwidth Analysis of Functional Interconnects Used as Test Access Mechanism

NARCIS (Netherlands)

Van den Berg, A.; Ren, P.; Marinissen, E.J.; Gaydadjiev, G.; Goossens, K.

2010-01-01

Test data travels through a System on Chip (SOC) from the chip pins to the Core-Under-Test (CUT) and vice versa via a Test Access Mechanism (TAM). Conventionally, a TAM is implemented using dedicated communication infrastructure. However, also existing functional interconnect, such as a bus or

Bandwidth analysis of functional interconnects used as test access mechanism

NARCIS (Netherlands)

Berg, van den Ardy; Ren, P.; Marinissen, Erik Jan; Gaydadjiev, G.N.; Goossens, K.G.W.

2010-01-01

Test data travels through a System on Chip (SOC) from the chip pins to the Core-Under-Test (CUT) and vice versa via a Test Access Mechanism (TAM). Conventionally, a TAM is implemented using dedicated communication infrastructure. However, also existing functional interconnect, such as a bus or

Upgraded Features of Newly Constructed Fuel Assembly Mechanical Characterization Test Facility in KAERI

Energy Technology Data Exchange (ETDEWEB)

Lee, Kang Hee; Kang, Heung Seok; Yoon, Kyung Ho; Kim, Hyung Kyu; Lee, Young Ho; Kim, Soo Ho; Yang, Jae Ho [KAERI, Daejeon (Korea, Republic of)

2016-05-15

Fuel assembly mechanical characterization test facility (FAMeCT) in KAERI is newly constructed with upgraded functional features such as increased loading capacity, under-water vibration testing and severe earthquake simulation for extended fuel design guideline. The facility building is compactly designed in the scale of 3rd floor building and has regions for assembly-wise mechanical test equipment, dynamic load (seismic) simulating test system, small scale hydraulic loop and component wise test equipment. Figure 1 shows schematic regional layout of the facility building. Mechanical test platform and system is designed to increase loading capacity for axial compression test. Structural stability of the support system of new upper core plate simulator is validated through a limit case functional test. Fuel assembly mechanical characterization test facility in KAERI is newly constructed and upgraded with advanced functional features such as uprated loading capacity, under-water vibration testing and severe earthquake simulation for extended fuel design guideline. This paper briefly introduce the test facility construction and scope of the facility and is focused on the upgraded design features of the facility. Authors hope to facilitate the facility more in the future and collaborate with the industry.

Mechanical characterization tests of the X2-Gen fuel assembly and skeleton

International Nuclear Information System (INIS)

Kim, Hyung Kyu; Yoon, Kyung Ho; Lee, Kang Hee; Kim, Jae Yong; Lee, Young Ho; Kang, Heung Seok

2011-01-01

The KNF (KEPCO Nuclear Fuel) requested mechanical characterization tests of a fuel assembly and a skeleton of the X2-Gen fuel. The tests consisted of the lateral vibration and lateral/axial stiffness, lateral/axial impact and combined deflection tests carried out by using the FAMeCT (Fuel Assembly Mechanical Characterization Tester) in KAERI. The upper and lower core plate simulators were newly designed and manufactured because the fuel geometry of the X2-Gen was different from the KSNP type fuel assembly. In addition to this, the upper carriage was also revised with the LM guide system from the previous two guide rods system. Therefore, the axial and combined deflection tests were soundly executed. Each test was repeated twice to confirm the repeatability. The discrepancy from the repetition was small enough to be neglected. The mechanical characterization tests were accredited with the KOLAS (Korea Laboratory Accreditation Scheme) standard, and the certified test reports (lateral vibration, lateral/axial bending and lateral/axial impact) and the uncertified test report (combined deflection) were issued together with the current test result report

Multiaxial pedicle screw designs: static and dynamic mechanical testing.

Science.gov (United States)

Stanford, Ralph Edward; Loefler, Andreas Herman; Stanford, Philip Mark; Walsh, William R

2004-02-15

Randomized investigation of multiaxial pedicle screw mechanical properties. Measure static yield and ultimate strengths, yield stiffness, and fatigue resistance according to an established model. Compare these measured properties with expected loads in vivo. Multiaxial pedicle screws provide surgical versatility, but the complexity of their design may reduce their strength and fatigue resistance. There is no published data on the mechanical properties of such screws. Screws were assembled according to a vertebrectomy model for destructive mechanical testing. Groups of five assemblies were tested in static tension and compression and subject to three cyclical loads. Modes of failure, yield, and ultimate strength, yield stiffness, and cycles to failure were determined for six designs of screw. Static compression yield loads ranged from 217.1 to 388.0 N and yield stiffness from 23.7 to 38.0 N/mm. Cycles to failure ranged from 42 x 10(3) to 4,719 x 10(3) at 75% of static ultimate load. There were significant differences between designs in all modes of testing. Failure occurred at the multiaxial link in static and cyclical compression. Bending yield strengths just exceeded loads expected in vivo. Multiaxial designs had lower static bending yield strength than fixed screw designs. Five out of six multiaxial screw designs achieved one million cycles at 200 N in compression bending. "Ball-in-cup" multiaxial locking mechanisms were vulnerable to fatigue failure. Smooth surfaces and thicker material appeared to be protective against fatigue failure.

SUPER-CAPACITOR APPLICATION IN ELECTRICAL POWER CABLE TESTING FACILITIES IN THERMAL ENDURANCE AND MECHANICAL BRACING TESTS

Directory of Open Access Journals (Sweden)

I. V. Oleksyuk

2015-01-01

Full Text Available The current-carrying cores of the electrical power cables should be resistant to effects of short-circuit currents whose values depend on the material of the core, its cross-sectional area, cable insulation properties, environment temperature, and the duration of the short-circuit current flow (1 and 3–4 sec. when tested for thermal endurance and mechanical bracing. The facilities for testing the 10 kV aluminum core cables with short-circuit current shall provide mechanical-bracing current 56,82 kA and thermal endurance current 11,16 kA. Although capacitors provide such values of the testing currents to the best advantage, utilizing conventional capacitor-units will involve large expenditures for erecting and  running a separate building. It is expedient to apply super-capacitors qua the electric power supply for testing facilities, as they are capacitors with double-electrical layer and involve the current values of tens of kilo-amperes.The insulation voltage during short-circuit current testing being not-standardized, it is not banned to apply voltages less than 10 kV when performing short-circuit thermal endurance and mechanical bracing tests for electrical power cables of 10 kV. The super-capacitor voltage variation-in-time graph consists of two regions: capacitive and resistive. The capacitive part corresponds to the voltage change consequent on the energy change in the super-capacitors. The resistive part shows the voltage variation due to the active resistance presence in the super-capacitor.The author offers the algorithm determining the number of super capacitors requisite for testing 10 kV-electrical power cables with short-circuit currents for thermal endurance and mechanical bracing. The paper shows that installation of super-capacitors in the facilities testing the cables with short-circuit currents reduces the area needed for the super-capacitors in comparison with conventional capacitors more than by one order of magnitude.

Pre-test habituation improves the reliability of a handheld test of mechanical nociceptive threshold in dairy cows

DEFF Research Database (Denmark)

Raundal, P. M.; Andersen, P. H.; Toft, Nils

2015-01-01

Mechanical nociceptive threshold (MNT) testing has been used to investigate aspects of painful states in bovine claws. We investigated a handheld tool, where the applied stimulation force was monitored continuously relative to a pre-encoded based target force. The effect on MNT of two pre-testing...... habituation procedures was performed in two different experiments comprising a total of 88 sound Holsteins dairy cows kept either inside or outside their home environment. MNT testing was performed using five consecutive mechanical nociceptive stimulations per cow per test at a fixed pre-encoded target rate...... of 2.1 N/s. The habituation procedure performed in dairy cows kept in their home environment led to lowered intra-individual coefficient of variation of MNT (P test...

Initiation of stress corrosion cracking in pre-stained austenitic stainless steels exposed to primary water

International Nuclear Information System (INIS)

Huguenin, P.

2012-01-01

Austenitic stainless steels are widely used in primary circuits of Pressurized Water Reactors (PWR) plants. However, a limited number of cases of Intergranular Stress Corrosion Cracking (IGSCC) has been detected in cold-worked (CW) areas of non-sensitized austenitic stainless steel components in French PWRs. A previous program launched in the early 2000's identified the required conditions for SCC of cold-worked stainless steels. It was found that a high strain hardening coupled with a cyclic loading favoured SCC. The present study aims at better understanding the role of pre-straining on crack initiation and at developing an engineering model for IGSCC initiation of 304L and 316L stainless steels in primary water. Such model will be based on SCC initiation tests on notched (not pre-cracked) specimens under 'trapezoidal' cyclic loading. The effects of pre-straining (tensile versus cold rolling), cold-work level and strain path on the SCC mechanisms are investigated. Experimental results demonstrate the dominating effect of strain path on SCC susceptibility for all pre-straining levels. Initiation can be understood as crack density and crack depth. A global criterion has been proposed to integrate both aspects of initiation. Maps of SCC initiation susceptibility have been proposed. A critical crack depth between 10 and 20 μm has been demonstrated to define transition between slow propagation and fast propagation for rolled materials. For tensile pre-straining, the critical crack depth is in the range 20 - 50 μm. Experimental evidences support the notion of a KISCC threshold, whose value depends on materials, pre-straining ant load applied. The initiation time has been found to depend on the applied loading as a function of (σ max max/YV) 11,5 . The effect of both strain path and surface hardening is indirectly taken into account via the yield stress. In this study, material differences rely on strain path effect on mechanical properties. As a result, a stress

The Diagnostic and Prognostic Value of Tumor Markers (CEA, SCC, CYFRA 21-1, TPS) in Head and Neck Cancer Patients.

Science.gov (United States)

Barak, Vivian; Meirovitz, Amichay; Leibovici, Vera; Rachmut, Jacob; Peretz, Tamar; Eliashar, Ron; Gross, Menachem

2015-10-01

Establishing prognostic factors is very important in the management of cancer patients. Our aim was to evaluate the clinical significance of a panel of tumor markers, including CEA (Carcino Embryonic Antigen), SCC (Squamous Cell Carcinoma Antigen), TPS (Tissue Polypeptide Specific Antigen) and CYFRA 21-1 in head and neck cancer patients, for assessing treatment response and prognosis of patients. We evaluated 312 blood samples from 143 head and neck cancer patients, from several sub-groups: 82 Larynx Carcinoma pre- and 38 post-therapy, 46 Oral Cavity pre and 29 post-therapy, 12 nasopharynx, 16 parotid and other salivary gland patients. Blood tumor markers levels were evaluated by conventional ELISA assays. Correlations of marker levels to stage of disease, lymph node involvement and therapy, were performed. Serum levels of all four tumor markers were higher before therapy and decreased thereafter in all patients. The decrease in TPS level following therapy was significant (p=0.03). Significantly higher levels of TPS and similarly higher levels of the other tumor markers were demonstrated in advanced disease (stages III and IV) patients, as opposed to early disease (stages I and II) patients (p=0.012). Node positive patients had significantly higher TPS levels as compared to node negative (p=0.02). The same trend was shown by the other markers as well, but did not reach statistical significance. TPS was best correlated to survival of patients; those having low levels had the best clinical outcome and longer survival. CEA, SCC, TPS and CYFRA 21-1 can all serve as useful tumor markers in HNC patients. They assessed response to therapy and were prognostic for recurrence. TPS proved to be the most sensitive predictor of advanced disease and poor prognosis. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Modulation of interferon-gamma-induced HLA-DR expression on the human keratinocyte cell line SCC-13 by ultraviolet radiation

International Nuclear Information System (INIS)

Khan, I.U.; Boehm, K.D.; Elmets, C.A.

1993-01-01

Cell surface expression of major histocompatibility determinants on epidermal keratinocytes is a characteristic feature of a number of inflammatory dermatoses and in all likelihood is caused by diffusion of human leukocyte antigen (HLA)-DR-inducing cytokines from cells present in the dermal mononuclear cell infiltrate. Many of these same disorders respond to ultraviolet (UV) radiation phototherapy. Using the human SCC-13 keratinocyte cell line as a model, UV radiation was found to inhibit interferon-gamma-induced HLA-DR expression. Inhibition correlated closely with decreased steady-state levels of HLA-DR mRNA. These findings provide evidence that the therapeutic effect of UV radiation phototherapy may be mediated by its capacity to down-regulate cytokine-induced keratinocyte HLA-DR expression. (Author)

Experimental study of optimal self compacting concrete with spent foundry sand as partial replacement for M-sand using Taguchi approach

Directory of Open Access Journals (Sweden)

Nirmala D.B.

2016-06-01

Full Text Available This paper presents the application of Taguchi approach to obtain optimal mix proportion for Self Compacting Concrete (SCC containing spent foundry sand and M-sand. Spent foundry sand is used as a partial replacement for M-sand. The SCC mix has seven control factors namely, Coarse aggregate, M-sand with Spent Foundry sand, Cement, Fly ash, Water, Super plasticizer and Viscosity modifying agent. Modified Nan Su method is used to proportion the initial SCC mix. L18 (21×37 Orthogonal Arrays (OA with the seven control factors having 3 levels is used in Taguchi approach which resulted in 18 SCC mix proportions. All mixtures are extensively tested both in fresh and hardened states to verify whether they meet the practical and technical requirements of SCC. The quality characteristics considering “Nominal the better” situation is applied to the test results to arrive at the optimal SCC mix proportion. Test results indicate that the optimal mix satisfies the requirements of fresh and hardened properties of SCC. The study reveals the feasibility of using spent foundry sand as a partial replacement of M-sand in SCC and also that Taguchi method is a reliable tool to arrive at optimal mix proportion of SCC.

Experimental study of optimal self compacting concrete with spent foundry sand as partial replacement for M-sand using Taguchi approach

Science.gov (United States)

Nirmala, D. B.; Raviraj, S.

2016-06-01

This paper presents the application of Taguchi approach to obtain optimal mix proportion for Self Compacting Concrete (SCC) containing spent foundry sand and M-sand. Spent foundry sand is used as a partial replacement for M-sand. The SCC mix has seven control factors namely, Coarse aggregate, M-sand with Spent Foundry sand, Cement, Fly ash, Water, Super plasticizer and Viscosity modifying agent. Modified Nan Su method is used to proportion the initial SCC mix. L18 (21×37) Orthogonal Arrays (OA) with the seven control factors having 3 levels is used in Taguchi approach which resulted in 18 SCC mix proportions. All mixtures are extensively tested both in fresh and hardened states to verify whether they meet the practical and technical requirements of SCC. The quality characteristics considering "Nominal the better" situation is applied to the test results to arrive at the optimal SCC mix proportion. Test results indicate that the optimal mix satisfies the requirements of fresh and hardened properties of SCC. The study reveals the feasibility of using spent foundry sand as a partial replacement of M-sand in SCC and also that Taguchi method is a reliable tool to arrive at optimal mix proportion of SCC.

Testing of mechanical ventilators and infant incubators in healthcare institutions.

Science.gov (United States)

Badnjevic, Almir; Gurbeta, Lejla; Jimenez, Elvira Ruiz; Iadanza, Ernesto

2017-01-01

The medical device industry has grown rapidly and incessantly over the past century. The sophistication and complexity of the designed instrumentation is nowadays rising and, with it, has also increased the need to develop some better, more effective and efficient maintenance processes, as part of the safety and performance requirements. This paper presents the results of performance tests conducted on 50 mechanical ventilators and 50 infant incubators used in various public healthcare institutions. Testing was conducted in accordance to safety and performance requirements stated in relevant international standards, directives and legal metrology policies. Testing of output parameters for mechanical ventilators was performed in 4 measuring points while testing of output parameters for infant incubators was performed in 7 measuring points for each infant incubator. As performance criteria, relative error of output parameters for mechanical ventilators and absolute error of output parameters for infant incubators was calculated. The ranges of permissible error, for both groups of devices, are regulated by the Rules on Metrological and Technical Requirements published in the Official Gazette of Bosnia and Herzegovina No. 75/14, which are defined based on international recommendations, standards and guidelines. All ventilators and incubators were tested by etalons calibrated in an ISO 17025 accredited laboratory, which provides compliance to international standards for all measured parameters.The results show that 30% of the tested medical devices are not operating properly and should be serviced, recalibrated and/or removed from daily application.

Self-Compacting Concrete Incorporating Micro-SiO2 and Acrylic Polymer

Directory of Open Access Journals (Sweden)

Ali Heidari

2014-01-01

Full Text Available This study examined the effects of using acrylic polymer and micro-SiO2 in self-compacting concrete (SCC. Using these materials in SCC improves the characteristics of the concrete. Self-compacting samples with 1-2% of a polymer and 10% micro-SiO2 were made. In all cases, compressive strength, water absorption, and self-compacting tests were done. The results show that adding acrylic polymer and micro-SiO2 does not have a significant negative effect on the mechanical properties of self-compacting concrete. In addition using these materials leads to improving them.

Mechanical test for fuel assembly spacer grid

International Nuclear Information System (INIS)

Kang, Heung Seok; Jeong, Yeon Ho; Song, Kee Nam; Kim, Hyung Kyu; Yoon, Kyung Ho; Bang, Je Keun.

1997-06-01

In order to propose some tests for a new spacer grid, the grid mechanical tests performed by ABB-CE, KWU and Westinghouse have been investigated. It is known that a static compression test, a dynamic impact test, and a grid spring characteristic test were commonly carried out by the vendors when a prototype spacer grid was developed. The static compression test is to measure the stresses on the strips as well as to obtain the grid stiffness. The dynamic impact test is to get some basic data for accident analysis such as impact stiffness, impact strength, and coefficient of restitution. Since each fuel vendor has his theory on an accident analysis, every vendor employs his particular method for the dynamic impact test. The dynamic impact test can be divided into two in accordance with the number of impact face, and the duration of impact pulse. One is an one-sided impact test and the other is an through-gird impact test. The duration of the impact pulse for the former is considerably shorter than the latter. Therefore, the grid can endure much higher load under the one-sided impact condition than under the through-grid impact condition. The grid spring characteristic test is to obtain a force versus deflection curve. This curve is very important in designing the spacer grid to provide fuel rods with a sound supports in core. (author). 18 tabs., 26 figs

Present status of mechanical testing technology at the Research Hot Laboratory

International Nuclear Information System (INIS)

Kizaki, M.; Tobita, T.; Koya, T.; Kikuchi, T.

1993-01-01

Mechanical tests of irradiated metallic materials at the Research Hot Laboratory(RHL) have been carried out for 30 years to support material research in JAERI and to evaluate the irradiation integrity of pressure vessel steel in commercial power plant. Two tensile testing machines and one Charpy impact testing machine are available for the examinations. One of the tensile testing machines has 1000 kgf load capacity under the vacuum of ∼ 10 -7 torr at the temperature of 1300degC max.. The other one has 10 tonf load capacity, and is utilized for the multi-purpose tests such as tensile and compressive tests in air atmosphere at the temperature between -160 and 900degC. Examinations cover tensile test, bending test, J ic fracture toughness test, low cycle fatigue test and so on. Charpy impact testing machine with notched-bar specimen is instrumented with 30 kgf-m capacity in the temperature range of -140 - 240 degC. To support these mechanical tests in RHL, special jigs, devices and instruments have been developed. (author)

Shaking table qualification tests of mechanical and electrical components

International Nuclear Information System (INIS)

Jurukovski, D.

1993-01-01

This presentation covers the experience of the Institute of Earthquake Engineering and Engineering Seismology, Skopje, Republic of Macedonia in seismic qualification of mechanical components by shaking table testing. The characteristics of the biaxial seismic and single component shaking tables used at the Institute are given. Some examples of the experience from performed test for reactor components are included

Subjective cognitive complaints and the role of executive cognitive functioning in the working population: a case-control study.

Directory of Open Access Journals (Sweden)

Cecilia U D Stenfors

Full Text Available BACKGROUND: Cognitive functioning is important for managing work and life in general. However, subjective cognitive complaints (SCC, involving perceived difficulties with concentration, memory, decision making, and clear thinking are common in the general and working population and can be coupled with both lowered well-being and work ability. However, the relation between SCC and cognitive functioning across the adult age-span, and in the work force, is not clear as few population-based studies have been conducted on non-elderly adults. Thus, the present study aimed to test the relation between SCC and executive cognitive functioning in a population-based sample of employees. METHODS: Participants were 233 employees with either high (cases or low (controls levels of SCC. Group differences in neuropsychological test performance on three common executive cognitive tests were analysed through a set of analyses of covariance tests, including relevant covariates. RESULTS & CONCLUSIONS: In line with the a priori hypotheses, a high level of SCC was associated with significantly poorer executive cognitive performance on all three executive cognitive tests used, compared to controls with little SCC. Additionally, symptoms of depression, chronic stress and sleeping problems were found to play a role in the relations between SCC and executive cognitive functioning. No significant associations remained after adjusting for all these factors. The current findings contribute to an increased understanding of what characterizes SCC in the work force and may be used at different levels of prevention of- and intervention for SCC and related problems with executive cognitive functioning.

New facts in mechanism, development and inspection of stress corrosion vulnerability in gas trunk lines; Nouveaux elements dans le mecanisme, le developpement et le diagnostic de la vulnerabilite a la corrosion sous tension des conduites de gaz principales

Energy Technology Data Exchange (ETDEWEB)

Ott, K. [Tyumentransgaz, (Russian Federation)

2000-07-01

Stress corrosion cracking (SCC) of the buried pipelines has been acknowledged a serious problem long ago. The author's researches (1) for a long period of time have established that SCC occurrence in pipe metal is affected by a combination of three factors: - Metal quality - availability of structural reasons contributing to occurrence and development of original microcracks; - Appropriate level of active stresses (considering inner residual stresses in the structure of metal), exceeding threshold level for occurrence and development of microcracks at rated operating conditions of the pipeline; - Availability of corrosive environment saturated with soil microorganisms, its access to the metal surface and interaction of the environment and metal structure. Operating failure mechanism and kinetics were proposed for buried pipelines - they give insight into, and enable to classify SCC cases as a local bio-corrosion process occurring in abnormal, in terms of content non-metallic spots, and offer to explain, in full, the features of the process that were hard to interpret before. (author)

Thermo-mechanical cementation effects in bentonite investigated by unconfined compression tests

International Nuclear Information System (INIS)

Dueck, Ann; Boergesson, Lennart; Karnland, Ola

2010-01-01

Document available in extended abstract form only. Mechanical properties of buffer material are included in the model used for predicting the physical behaviour of saturated buffer in the final disposal of spent nuclear fuel. One simple test where the mechanical properties can be quantified is the unconfined compression test. In this type of test the relation between stress and strain are determined from axial compression of a cylindrical specimen. In the project LOT the unconfined compression test was used to study the mechanical properties on field exposed buffer material. The results from these test series showed that specimens exposed to warm conditions had a significantly reduced strain at failure compared to reference material. Changes in mechanical properties may be due to incipient chemical changes in the material. However, the present study focuses on other possible sources for brittle failure behaviour. In this study the objective was to experimentally investigate if deviating stress-strain behaviour measured after temperature exposure could be explained by Thermo-Hydro-Mechanical processes. The word cementation is used as a general term for the process involving a change in mechanical properties including brittleness at failure. A relatively large number of specimens were tested representing sodium dominated and calcium dominated bentonites. Cylindrical specimens were compacted from air dry powder to a height and diameter of 20 mm. The main part of the specimens was put in a saturation device prior to the tests in order to ensure full saturation. After the saturation each sample was placed in a mechanical press where a constant rate of strain was applied axially to the specimens having no radial confinement. During the test the deformation and the applied force were measured by means of force and strain transducers. After failure the water content and density were determined. Test series were carried out for investigating the influence of for example

The Use of Waste Maroon Marble Powder and Iron Oxide Pigment in the Production of Coloured Self-Compacting Concrete

Directory of Open Access Journals (Sweden)

Mucteba Uysal

2018-01-01

Full Text Available This work covers some workability, mechanical, and durability properties of coloured self-compacting concrete (SCC containing maroon marble powder and iron oxide pigment. Pigments with varying amounts were used to produce coloured SCC. For this purpose, ten different series were prepared of which two of the series were pigment free that one of them was the colour of white SCC including limestone powder and the other one was the colour of maroon SCC including maroon marble powder. The other series were containing pigments with varying amounts. The water to binder ratio remained constant for all the series at 0.42. Slump flow, T50 time, V-funnel, and L-box tests were used to determine the workability of coloured SCC. The hardened properties that were determined included density, water absorption, ultrasonic pulse velocity (UPV, compressive strength, abrasion resistance, and impermeability. As workability, experimental results showed that coloured SCC could be obtained by using maroon marble powder and when iron oxide pigment used in amounts less than 6%. The addition of pigment notably increased the water absorption of SCC series. The use of smaller quantities of pigment caused slight increase in compressive strength. Higher pigment content also provided decreases in abrasive resistance, and after exposure to abrasion, mass losses were within the range of 0.89%–2.12% and the abrasion depths were within the range of 0.9 mm–2.1 mm. Among the varying amounts of pigmented series, M1 series which contains 1% pigment showed the best performance, and the findings indicated that it is possible to successfully utilize maroon marble powder and lower amounts of pigments in producing coloured SCC.

The role of epithelial-mesenchymal transition in squamous cell carcinoma of the oral cavity.

Science.gov (United States)

Zidar, Nina; Boštjančič, Emanuela; Malgaj, Marija; Gale, Nina; Dovšak, Tadej; Didanovič, Vojko

2018-02-01

Epithelial-mesenchymal transition (EMT) has emerged as a possible mechanism of cancer metastasizing, but strong evidence for EMT involvement in human cancer is lacking. Our aim was to compare oral spindle cell carcinoma (SpCC) as an example of EMT with oral conventional squamous cell carcinoma (SCC) with and without nodal metastases to test the hypothesis that EMT contributes to metastasizing in oral SCC. Thirty cases of oral SCC with and without nodal metastasis and 15 cases of SpCC were included. Epithelial (cytokeratin, E-cadherin), mesenchymal (vimentin, N-cadherin), and stem cell markers (ALDH-1, CD44, Nanog, Sox-2) and transcription repressors (Snail, Slug, Twist) were analyzed immunohistochemically. We also analyzed the expression of microRNAs miR-141, miR-200 family, miR-205, and miR-429. SpCC exhibited loss of epithelial markers and expression of mesenchymal markers or coexpression of both up-regulation of transcription repressors and down-regulation of the investigated microRNAs. SCC showed only occasional focal expression of mesenchymal markers at the invasive front. No other differences were observed between SCC with and without nodal metastases except for a higher expression of ALDH-1 in SCC with metastases. Our results suggest that SpCC is an example of true EMT but do not support the hypothesis that EMT is involved in metastasizing of conventional SCC. Regarding oral SCC progression and metastasizing, we have been facing a shift from the initial enthusiasm for the EMT concept towards a more critical approach with "EMT-like" and "partial EMT" concepts. The real question, though, is, is there no EMT at all?

Modification and Performance Evaluation of a Low Cost Electro-Mechanically Operated Creep Testing Machine

OpenAIRE

John J. MOMOH; Lanre Y. SHUAIB-BABATA; Gabriel O. ADELEGAN

2010-01-01

Existing mechanically operated tensile and creep testing machine was modified to a low cost, electro-mechanically operated creep testing machine capable of determining the creep properties of aluminum, lead and thermoplastic materials as a function of applied stress, time and temperature. The modification of the testing machine was necessitated by having an electro-mechanically operated creep testing machine as a demonstration model ideal for use and laboratory demonstrations, which will prov...

Defect detectability of eddy current testing for underwater laser beam welding

International Nuclear Information System (INIS)

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

2011-01-01

We clarified defect detectability of eddy current testing (ECT) as a surface inspection technique for underwater laser beam welding works of dissimilar metal welding (DMW) of reactor vessel nozzle. The underwater laser beam welding procedure includes groove caving as a preparation, laser beam welding in the grooves and welded surface grinding as a post treatment. Therefore groove and welded surface inspections are required in the underwater condition. The ECT is a major candidate as this inspection technique because a penetrant testing is difficult to perform in the underwater condition. Several kinds of experiments were curried out using a cross coil an ECT probe and ECT data acquisition system in order to demonstrate the ECT defect detectability. We used specimens, simulating groove and DMW materials at an RV nozzle, with electro-discharge machining (EDM) slits over it. Additionally, we performed a detection test for artificial stress corrosion cracking (SCC) defects. From these experimental results, we confirmed that an ECT was possible to detect EDM slits 0.3 mm or more in depth and artificial SCC defects 0.02 mm to 0.48 mm in depth on machined surface. Furthermore, the underwater ECT defect detectability is equivalent to that in air. We clarified an ECT is sufficiently usable as a surface inspection technique for underwater laser beam welding works. (author)

Fast Flux Test Facility sodium pump operating experience - mechanical

International Nuclear Information System (INIS)

Buonamici, R.

1987-11-01

The Heat Transport System (HTS) pumps were designed, fabricated, tested, and installed in the Fast Flux Test Facility (FFTF) Plant during the period from September 1970 through July 1977. Since completion of the installation and sodium fill in December 1978, the FFTF Plant pumps have undergone extensive testing and operation with HTS testing and reactor operation. Steady-state hydraulic and mechanical performances have been and are excellent. In all, FFTF primary and secondary pumps have operated in sodium for approximately 75,000 hours and 79,000 hours, respectively, to August 24, 1987

Monte Carlo simulation taking account of surface crack effect for stress corrosion cracking in a stainless steel SUS 304

International Nuclear Information System (INIS)

Tohgo, Keiichiro; Suzuki, Hiromitsu; Shimamura, Yoshinobu; Nakayama, Guen; Hirano, Takashi

2008-01-01

Stress corrosion cracking (SCC) in structural metal materials occurs by initiation and coalescence of micro cracks, subcritical crack propagation and multiple large crack formation or final failure under the combination of materials, stress and corrosive environment. In this paper, a Monte Carlo simulation for the process of SCC has been proposed based on the stochastic properties of micro crack initiation and fracture mechanics concept for crack coalescence and propagation. The emphasis in the model is put on the influence of semi-elliptical surface cracks. Numerical simulations are carried out based on CBB (creviced bent beam) test results of a sensitized stainless steel SUS 304 and the influence of micro crack initiation rate and coalescence condition on the simulation results is discussed. The numerical examples indicate the applicability of the present model to a prediction of the SCC behavior in real structures. (author)

Dosimetry of irradiation models. The 96-well clonogenic assay for testing radiosensitivity of cell lines

International Nuclear Information System (INIS)

Kulmala, J.; Rantanen, V.; Turku Univ.; Pekkola-Heino, K.; Turku Univ.; Tuominen, J.; Grenman, R.; Turku Univ.

1995-01-01

Radiation experiments with cells in single cell suspension in test tubes and on 96-well plates were carried out and compared. The cells originated from cell lines established from carcinomas of the floor of the mouth and from endometrical carcinoma. Two irradiation models were constructed. Both models allowed the absorbed doses to the cells to be administered with a high accuracy in both experimental settings (better than 5.0%). These irradiation models were compared on cancer cell lines with dissimilar inherent radiation sensitivity and histologic type (UM-SCC-1 resistant, UM-SCC-14A sensitive, and UT-EC-2B highly sensitive); various radiation doses were used. The fractions of surviving cells as a function of radiation dose were compared: there was no significant difference between cells irradiated in test tubes and cells irradiated in 96-well plates. Thus, if the absorbed doses in cells suspended in a tube and in a plate were the same, the survival was similar regardless of the type of irradiation model. (orig.)

Multiscale mechanics of TRIP-assisted multiphase steels: I. Characterization and mechanical testing

International Nuclear Information System (INIS)

Jacques, P.J.; Furnemont, Q.; Lani, F.; Pardoen, T.; Delannay, F.

2007-01-01

The mechanical behaviour of transformation-induced plasticity (TRIP)-assisted multiphase steels is addressed based on three different microstructures generated from the same steel grade. The mechanisms responsible for the work-hardening capacity and the resulting balance between strength and resistance to plastic localization are investigated at different length scales. The macroscopic mechanical response is determined by simple shear, uniaxial tension, Marciniak and equibiaxial tension supplemented by earlier tensile tests on notched and cracked specimens. It is shown that the transformation rate reaches a maximum for stress states intermediate between uniaxial tension and equibiaxial tension. At an intermediate length scale, the true in situ flow properties of the individual ferrite-bainite and retained austenite phases are determined by combining neutron diffraction and digital image correlation. This combined analysis elucidates the partitioning of stress and strain between the different constitutive phases. Based on these results, supplemented by transmission electron microscopy and electron backscattered diffraction observations, a general overview of the hardening behaviour of TRIP-assisted multiphase steels is depicted

A neonatal mouse spinal cord injury model for assessing post-injury adaptive plasticity and human stem cell integration.

Directory of Open Access Journals (Sweden)

Jean-Luc Boulland

Full Text Available Despite limited regeneration capacity, partial injuries to the adult mammalian spinal cord can elicit variable degrees of functional recovery, mediated at least in part by reorganization of neuronal circuitry. Underlying mechanisms are believed to include synaptic plasticity and collateral sprouting of spared axons. Because plasticity is higher in young animals, we developed a spinal cord compression (SCC injury model in the neonatal mouse to gain insight into the potential for reorganization during early life. The model provides a platform for high-throughput assessment of functional synaptic connectivity that is also suitable for testing the functional integration of human stem and progenitor cell-derived neurons being considered for clinical cell replacement strategies. SCC was generated at T9-T11 and functional recovery was assessed using an integrated approach including video kinematics, histology, tract tracing, electrophysiology, and high-throughput optical recording of descending inputs to identified spinal neurons. Dramatic degeneration of axons and synaptic contacts was evident within 24 hours of SCC, and loss of neurons in the injured segment was evident for at least a month thereafter. Initial hindlimb paralysis was paralleled by a loss of descending inputs to lumbar motoneurons. Within 4 days of SCC and progressively thereafter, hindlimb motility began to be restored and descending inputs reappeared, but with examples of atypical synaptic connections indicating a reorganization of circuitry. One to two weeks after SCC, hindlimb motility approached sham control levels, and weight-bearing locomotion was virtually indistinguishable in SCC and sham control mice. Genetically labeled human fetal neural progenitor cells injected into the injured spinal cord survived for at least a month, integrated into the host tissue and began to differentiate morphologically. This integrative neonatal mouse model provides opportunities to explore early

Analytical Tem Comparisons of Stress-Corrosion-Crack Microstructures in Alloy 600 under Steam-Generator Service and Laboratory Test Conditions

International Nuclear Information System (INIS)

Thomas, L.E.; Bruemmer, S.M.; Scott, P.M.

2002-01-01

High-resolution analytical transmission electron microscopy (ATEM) has been used to characterize stress-corrosion cracks (SCC) in Alloy 600 steam-generator (SG) tubing from tests with caustic and acid-sulfate solutions. The aim of this work was to identify the microstructural and microchemical signatures of intergranular attack and cracking produced under well-controlled test conditions in order to determine the local environments promoting degradation in service. Cross-sectioned cracks and crack tips were examined in samples of mill-annealed alloy 600 tested in concentrated caustic and acid-sulfate solutions at 320 C. Characteristic microstructures observed in the caustic (10% NaOH) test sample included deeply penetrative attack along crack-intersected grain boundaries, with Cr-rich spinel and NiO structure oxides ranging from random nanocrystalline to oriented epitaxial films filling cracks up to the tips. Sodium was readily detectable in the oxides (up to 5 wt.% in the spinel corrosion product) along with S and Cu enrichment at crack-wall metal/oxide interfaces and local attack of the metal matrix around IG carbide particles. In the sulfate (Na 2 SO 4 + FeSO 4 ) test sample, the grain boundaries were also deeply attacked/cracked. Epitaxial NiO-structure oxide formed on the crack walls and S, sometimes with Cu, was concentrated between the oriented oxide layers rather than along the metal/oxide interfaces. Carbides were attacked and partially converted to fine-grained oxide containing up to several percent S. Observations of crack tips in the acid sulfate sample also revealed nm-wide cracks preceding the oxide along grain boundaries. The SCC structures produced in the laboratory tests differed in most details from the secondary-side SCC structures observed in pulled SG tubes. Important differences included the oxide morphologies, the presence of easily detectable Na and absence of sulfides in the test samples, different types of attack on IG carbide particles

Testing the foundations of quantum mechanics

CERN Document Server

Gisin, Nicolas; CERN. Geneva

1999-01-01

Quantum mechanics is certainly one of the most fascinating field of physics. In recent years, the new field of "quantum information processing" based on the most fundamental aspect of quantum mechanics, like linearity and entanglement, even increased and its peculiarities. In this series of 4 lectures we shall present some of the issues and experiments that test quantum theory. Entanglement leads, on the one hand side, to the measurement problem, to the EPR paradox and to quantum nonlocality ( distant systems). We will derive the Bell inequality, present experimental results that provide huge evidence in favor of quantum nonlocality and discuss some loopholes that are still open. On the other side, entanglement offers many new possibilities for information processing. Indeed, it provides means to carry out tasks that are either impossible classically (like quantum cryptography and quantum teleportation) or that would require significantly more steps to perform on a classical computer (like searching a databas...

Experimental Studies of Sealing Mechanism of a Dismountable Microsystem-to-Macropart Fluidic Connector for High Pressure and a Wide Range of Temperature

Directory of Open Access Journals (Sweden)

Hugo Nguyen

2010-01-01

Full Text Available As fluidic microelectromechanical devices are developing and often attached to, or embedded in, large, complex, and expensive systems, the issues of modularity, maintenance, and subsystem replacement arise. In this work, a robust silicon connector suitable for high-pressure applications—likely with harsh fluids—in the temperature range of +100 to −100° C is demonstrated and tested together with a stainless steel nipple representing a simple and typical macropart. With a micromachined circular membrane equipped with a 5 μm high ridge, this connector is able to maintain a leak rate below 2.0×10−8 scc/s of gaseous helium with a pressure of up to 9.7 bar. Degradation of the sealing performance on reassembly is associated with the indentation of the ridge. However, the ridge makes the sealing interface less sensitive to particles in comparison with a flat reference. Most evaluation is made through the so-called heat-until-leak tests conducted to determine the maximum working temperature and the sealing mechanism of the connector. A couple of these are followed by cryogenic testing. The effect of thermal mismatch of the components is discussed and utilized as an early warning mechanism.

Analysis of a proposed crucial test of quantum mechanics

International Nuclear Information System (INIS)

Collett, M.J.; Loudon, R.

1987-01-01

An experiment based on an extension of the Einstein-Podolsky-Rosen argument has been proposed by Popper as a crucial test of the Copenhagen interpretation of quantum mechanics. Here the authors show, by a slightly more complete version of Popper's analysis, although still at a relatively primitive level of sophistication, that the proposed experiment does not in fact provide such a test. (author)

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

Intergranular stress corrosion cracking of low alloy and carbon steels in high temperature pure water

International Nuclear Information System (INIS)

Tsubota, M.; Sakamoto, H.; Tsuzuki, R.

1993-01-01

Stress corrosion cracking (SCC) behavior of low alloy steels (A508 and SNCM630) and a carbon steel (SGV480) in high temperature water has been examined with relation to the heat treatment condition, including a long time aging, and the mechanical properties. Intergranular stress corrosion cracking (IGSCC) as observed in the highly hardened specimens, and there was observed in the highly hardened specimens, and there was observed in the highly hardened specimens, and there was observed a close relationship between hardness and SCC susceptibility. From the engineering point of view, it was concluded that adequate SR (stress relief) or tempering heat treatment is necessary to avoid the IGSCC of the welded structures made of low alloy and carbon steels. A508 heat treated with specified quench and temper did not show the SCC susceptibility, even after aging 10000 hours at 350, 400 and 450 degrees C. Tensile properties corresponding to the critical hardness for SSC susceptibility coincided with the values at the 'necking point' in the true stress-strain curve. Ductile-brittle transition observed in the fracture toughness test also occurred at around the critical hardness for SCC susceptibility. Therefore, it was conjectured that the limitation of plasticity was an absolute cause for the SCC susceptibility of the steels

Qualification tests for PWR control element drive mechanism

Energy Technology Data Exchange (ETDEWEB)

Kim, In Yong; Jin, Choon Eon; Choi Suhn [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1996-01-01

It is necessary to perform the qualification test for the magnetic jack type CEDM to show the design compatibility because the CEDM is composed of many mechanical and electrical components complicatedly. ABB-CE performed various qualification tests during the development of the System80 CEDM to which Korea Standard Nuclear Plant (KSNP) CEDM referred. The qualification test for the CEDM is classified into the performance test and the dynamic test. The performance test is to verify operability of the CEDM, and the dynamic test is to find dynamic characteristics and to verify the structural integrity if the CEDM for the seismic accidents. Described in this report are the test requirements, the test facilities and the test methods for the performance and the dynamic qualification tests of the PWR magnetic jack type CEDM. The impacts of the design changes in the Korea Next Generation Reactor (KNGR) on the KSNP CEDM were analyzed to present the necessity for the tests. This report also proposes the facilities to perform the tests in KAERI including reasonable schedule for the tests. Attached to this report is the summary of qualification tests of System 80 CEDM performed by ABB-CE. 20 figs., 16 tabs., 21 refs. (Author) .new.

Qualification tests for PWR control element drive mechanism

International Nuclear Information System (INIS)

Kim, In Yong; Jin, Choon Eon; Choi Suhn

1996-01-01

It is necessary to perform the qualification test for the magnetic jack type CEDM to show the design compatibility because the CEDM is composed of many mechanical and electrical components complicatedly. ABB-CE performed various qualification tests during the development of the System80 CEDM to which Korea Standard Nuclear Plant (KSNP) CEDM referred. The qualification test for the CEDM is classified into the performance test and the dynamic test. The performance test is to verify operability of the CEDM, and the dynamic test is to find dynamic characteristics and to verify the structural integrity if the CEDM for the seismic accidents. Described in this report are the test requirements, the test facilities and the test methods for the performance and the dynamic qualification tests of the PWR magnetic jack type CEDM. The impacts of the design changes in the Korea Next Generation Reactor (KNGR) on the KSNP CEDM were analyzed to present the necessity for the tests. This report also proposes the facilities to perform the tests in KAERI including reasonable schedule for the tests. Attached to this report is the summary of qualification tests of System 80 CEDM performed by ABB-CE. 20 figs., 16 tabs., 21 refs. (Author) .new

Evaluation of limiting mechanisms for long-term spent fuel dry storage

International Nuclear Information System (INIS)

Rashid, J.; Machiels, A.

2001-01-01

Several failure mechanisms have been postulated that could become limiting for spent fuel in dry storage. These are: stress Corrosion Cracking (SCC), Delayed Hydride Cracking (DHC) and Creep Rupture (CR). These mechanisms are examined in some detail from two perspectives: their initial environments in which they were developed and applied, and in relation to their applicability to dry storage. Extrapolation techniques are used to transfer the mechanisms from their initial in-reactor and laboratory domains to out-of-reactor spent fuel dry storage environments. This transfer is accomplished both qualitatively where necessary and quantitatively when possible, with fracture toughness used as the transfer function. In this regard, the paper provides useful information on cladding fracture toughness estimates that recognize the specific physical conditions of the cladding, which would not be found elsewhere in the literature. The arguments presented in this paper confirm the general technical consensus that creep is the governing mechanism for spent fuel in long-term dry storage. (author)

Evaluation of limiting mechanisms for long-term spent fuel dry storage

Energy Technology Data Exchange (ETDEWEB)

Rashid, J. [ANATECH Research Corp., San Diego, CA (United States); Machiels, A. [EPRI, Palo Alto, CA (United States)

2001-07-01

Several failure mechanisms have been postulated that could become limiting for spent fuel in dry storage. These are: stress Corrosion Cracking (SCC), Delayed Hydride Cracking (DHC) and Creep Rupture (CR). These mechanisms are examined in some detail from two perspectives: their initial environments in which they were developed and applied, and in relation to their applicability to dry storage. Extrapolation techniques are used to transfer the mechanisms from their initial in-reactor and laboratory domains to out-of-reactor spent fuel dry storage environments. This transfer is accomplished both qualitatively where necessary and quantitatively when possible, with fracture toughness used as the transfer function. In this regard, the paper provides useful information on cladding fracture toughness estimates that recognize the specific physical conditions of the cladding, which would not be found elsewhere in the literature. The arguments presented in this paper confirm the general technical consensus that creep is the governing mechanism for spent fuel in long-term dry storage. (author)

Thermo-hydro-mechanical tests of buffer material

International Nuclear Information System (INIS)

Pintado, X.; Hassan, Md. M.; Martikainen, J.

2013-10-01

MX-80 bentonite is the reference clay material for the buffer component planned to be used in the deep geological repository for the disposal of spent nuclear fuel in Finland. The buffer presents complex thermo-hydro-mechanical behavior which is modeled with different constitutive models for heat flow, water flow and stress-strain evolution in the buffer. Thermo, hydro and mechanical models need parameters to evaluate the THM-behavior. These modeling parameters were determined by performing series of laboratory experiments as follows: Water retention curve tests were performed on compacted bentonite samples, encompassing a range of initial dry density values from 1397 to 1718 kg/m 3 as the initial water content was around of 5-8 %. The water retention curve was determined by imposing different suctions to the samples and the suctions were then checked using capacitive hygrometer and chilled mirror psychrometer. Oedometer tests were performed on compacted bentonite samples, encompassing a range of initial dry density values from 1590 to 1750 kg/m 3 as the initial water content was around of 6 %. Samples were saturated with tap water, 35 or 70 g/L salt solutions. Infiltration tests were performed on compacted unsaturated bentonite samples, encompassing a range of initial dry density values from 1400 to 1720 kg/m 3 as the initial water content was approximately between 4-7 %. Samples were saturated with tap water, 0.87, 35 or 70 g/L salt solutions. Tortuosity tests were performed on bentonite samples, encompassing a range of dry density values from 1460 to 1750 kg/m 3 and the degree of saturation varied between 33-93 %. Thermal conductivity tests were performed on compacted bentonite samples, encompassing a range of dry density values from 1545 to 1715 kg/m 3 and the degree of saturation varied between 31-88 %. The measurement was performed using a thermal needle probe. The general trend of all analyzed parameters was as expected when dry density, water content, and

Thermo-hydro-mechanical tests of buffer material

Energy Technology Data Exchange (ETDEWEB)

Pintado, X.; Hassan, Md. M.; Martikainen, J. [B and Tech Oy, Helsinki (Finland)

2013-10-15

MX-80 bentonite is the reference clay material for the buffer component planned to be used in the deep geological repository for the disposal of spent nuclear fuel in Finland. The buffer presents complex thermo-hydro-mechanical behavior which is modeled with different constitutive models for heat flow, water flow and stress-strain evolution in the buffer. Thermo, hydro and mechanical models need parameters to evaluate the THM-behavior. These modeling parameters were determined by performing series of laboratory experiments as follows: Water retention curve tests were performed on compacted bentonite samples, encompassing a range of initial dry density values from 1397 to 1718 kg/m{sup 3} as the initial water content was around of 5-8 %. The water retention curve was determined by imposing different suctions to the samples and the suctions were then checked using capacitive hygrometer and chilled mirror psychrometer. Oedometer tests were performed on compacted bentonite samples, encompassing a range of initial dry density values from 1590 to 1750 kg/m{sup 3} as the initial water content was around of 6 %. Samples were saturated with tap water, 35 or 70 g/L salt solutions. Infiltration tests were performed on compacted unsaturated bentonite samples, encompassing a range of initial dry density values from 1400 to 1720 kg/m{sup 3} as the initial water content was approximately between 4-7 %. Samples were saturated with tap water, 0.87, 35 or 70 g/L salt solutions. Tortuosity tests were performed on bentonite samples, encompassing a range of dry density values from 1460 to 1750 kg/m{sup 3} and the degree of saturation varied between 33-93 %. Thermal conductivity tests were performed on compacted bentonite samples, encompassing a range of dry density values from 1545 to 1715 kg/m{sup 3} and the degree of saturation varied between 31-88 %. The measurement was performed using a thermal needle probe. The general trend of all analyzed parameters was as expected when dry

Temperature buffer test. Hydro-mechanical and chemical/ mineralogical characterizations

International Nuclear Information System (INIS)

Aakesson, Mattias; Olsson, Siv; Dueck, Ann; Nilsson, Ulf; Karnland, Ola; Kiviranta, Leena; Kumpulainen, Sirpa; Linden, Johan

2012-01-01

The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modeling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aspo HRL. It was installed during the spring of 2003. Two steel heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by rings of compacted Wyoming bentonite only, whereas the upper heater was surrounded by a composite barrier, with a sand shield between the heater and the bentonite. The test was dismantled and sampled during the winter of 2009/2010. This report presents the hydro-mechanical and chemical/mineralogical characterization program which was launched subsequent to the dismantling operation. The main goal has been to investigate if any significant differences could be observed between material from the field experiment and the reference material. The field samples were mainly taken from Ring 4 (located at the mid-section around the lower heater), in which the temperature in the innermost part reached 155 deg C. The following hydro-mechanical properties have been determined for the material (test technique within brackets): hydraulic conductivity (swelling pressure device), swelling pressure (swelling pressure device), unconfined compression strength (mechanical press), shear strength (triaxial cell) and retention properties (jar method). The following chemical/mineralogical properties (methods within brackets) were determined: anion analysis of water leachates (IC), chemical composition (ICP/AES+MS, EGA), cation exchange capacity (CEC, Cu-trien method) and exchangeable cations (exchange with NH4, ICPAES), mineralogical composition (XRD and FTIR), element distribution and microstructure (SEM and

Eight plane IPND [Integration Prototype Near Detector] mechanical testing

International Nuclear Information System (INIS)

Zhao, A.; Guarino, V.; Wood, K.; Nephew, T.; Ayres, D.

2008-01-01

A mechanical test of an 8 plane IPND mechanical prototype, which was constructed using extrusions from the testing/tryout of the 16 cell prototype extrusion die in Argonne National Laboratory, was conducted. There were 4 vertical and 4 horizontal planes in this 8 plane IPND prototype. Each vertical plane had four 16 cell extrusions, while each horizontal plane had six 16 cell extrusions. Each plane was glued together using the formulation of Devcon adhesive, Devcon 60. The vertical extrusions used in the vertical planes shares the same dimensions as the horizontal extrusions in the horizontal planes with the average web thickness of 2.1 mm and the average wall thickness of 3.1 mm. This mechanical prototype was constructed with end-seals on the both ends of the vertical extrusions. The gaps were filled with epoxy between extrusions and end-seals. The overall dimension of IPND is 154.8 by 103.1 by 21.7 inches with the weight of approximately 1200 kg, as shown in a figure. Two similar mechanical tests of 3 layer and 11 layer prototypes have been done in order to evaluate the strength of the adhesive joint between extrusions in the NOvA detector. The test showed that the IPND prototype was able to sustain under the loading of weight of itself and scintillator. Two FEA models were built to verify the measurement data from the test. The prediction from FEA slice model seems correlated reasonably well to the test result, even under a 'rough' estimated condition for the wall thickness (from an untuned die) and an unknown property of 'garage type' extrusion. A full size of FEA 3-D model also agrees very well with the test data from strain gage readings. It is worthy to point out that the stress distribution of the structure is predominantly determined by the internal pressure, while the buckling stability relies more on the loading weight from the extrusions themselves and scintillate. Results of conducted internal pressure tests, including 3- cell, 11-cell and the IPND

User's manuals of probabilistic fracture mechanics analysis code for aged piping, PASCAL-SP

International Nuclear Information System (INIS)

Itoh, Hiroto; Nishikawa, Hiroyuki; Onizawa, Kunio; Kato, Daisuke; Osakabe, Kazuya

2010-03-01

As a part of research on the material degradation and structural integrity assessment for aged LWR components, a PFM (Probabilistic Fracture Mechanics) analysis code PASCAL-SP (PFM Analysis of Structural Components in Aging LWR - Stress Corrosion Cracking at Welded Joints of Piping) has been developed. This code evaluates the failure probabilities at welded joints of aged piping by a Monte Carlo method. PASCAL-SP treats stress corrosion cracking (SCC) and fatigue crack growth in piping, according to the approaches of NISA and JSME FFS Code. The development of the code has been aimed to improve the accuracy and reliability of analysis by introducing new analysis methodologies and algorithms considering the latest knowledge in the SCC assessment and fracture criteria of piping. In addition, the accuracy of flaw detection and sizing at in-service inspection and residual stress distribution were modeled based on experimental data and introduced into PASCAL-SP. This code has been developed for a cross-check use by the regulatory body in Japan. In addition to this, this code can also be used for a research purpose by researchers in academia and industries. This report provides the user's manual and theoretical background of the code. (author)

Microstructural characterization of titanium dental implants by electron microscopy and mechanical tests

International Nuclear Information System (INIS)

Helfenstein, B.; Muniz, N.O.; Dedavid, B.A.; Gehrke, S.A.; Vargas, A.L.M.

2010-01-01

Mini screw types for titanium implants, with differentiated design, were tested for traction and torsion for behavior analysis of the shape relative to the requirements of ASTM F136. All implants showed mechanical tensile strength above by the standard requirement, being that 83.3% of them broke above the doughnut, in support of the prosthesis. Distinct morphologies in ruptured by mechanical tests, were obtained. However, both fracture surfaces showed fragile comportments. Metallographic tests, x-ray diffraction (XRD) and microhardness were used for microstructural characterization of material, before and after heat treatment. The presences of β phase in screw surface after quenching treatment proves that the thermal treatment can contribute for mechanical resistance in surface implants. (author)

Quantum Mechanics/Molecular Mechanics Simulations Identify the Ring-Opening Mechanism of Creatininase.

Science.gov (United States)

Jitonnom, Jitrayut; Mujika, Jon I; van der Kamp, Marc W; Mulholland, Adrian J

2017-12-05

Creatininase catalyzes the conversion of creatinine (a biosensor for kidney function) to creatine via a two-step mechanism: water addition followed by ring opening. Water addition is common to other known cyclic amidohydrolases, but the precise mechanism for ring opening is still under debate. The proton donor in this step is either His178 or a water molecule bound to one of the metal ions, and the roles of His178 and Glu122 are unclear. Here, the two possible reaction pathways have been fully examined by means of combined quantum mechanics/molecular mechanics simulations at the SCC-DFTB/CHARMM22 level of theory. The results indicate that His178 is the main catalytic residue for the whole reaction and explain its role as proton shuttle during the ring-opening step. In the first step, His178 provides electrostatic stabilization to the gem-diolate tetrahedral intermediate. In the second step, His178 abstracts the hydroxyl proton of the intermediate and delivers it to the cyclic amide nitrogen, leading to ring opening. The latter is the rate-limiting step with a free energy barrier of 18.5 kcal/mol, in agreement with the experiment. We find that Glu122 must be protonated during the enzyme reaction, so that it can form a stable hydrogen bond with its neighboring water molecule. Simulations of the E122Q mutant showed that this replacement disrupts the H-bond network formed by three conserved residues (Glu34, Ser78, and Glu122) and water, increasing the energy barrier. Our computational studies provide a comprehensive explanation for previous structural and kinetic observations, including why the H178A mutation causes a complete loss of activity but the E122Q mutation does not.

Stress corrosion cracking of zirconium and its alloys in halogenide solutions

International Nuclear Information System (INIS)

Farina, Silvia B.

2001-01-01

A doctoral thesis developed at the corrosion labs in CNEA a few years ago showed that zirconium and Zircaloy-4 were susceptible to stress corrosion cracking (SCC) in chloride aqueous solutions at potentials above the pitting potential. However, the nature of the phenomenon was not elucidated. On the other hand, references about the subject were scarce and contradictory. The development of new SCC models, in particular, the surface mobility SCC mechanism suggested a review of zirconium and Zircaloy-4 SCC in halogenide aqueous solutions. This mechanism predicts that zirconium should be susceptible to SCC not only in chloride solutions but also in bromide and iodide solutions due to the low melting point of the surface compounds formed by the interaction between the metal and the environment. The present work was aimed to determine the conditions under which SCC takes place and the mechanism operating during this process. For that purpose, the effect of electrochemical potential, strain rate and temperature on the SCC susceptibility of both, zirconium and Zircaloy-4 in chloride, bromide and iodide solutions was investigated. It was observed that those materials undergo stress corrosion cracking only at potentials higher than the breakdown potential. The crack velocity increased slightly with the applied potential, and the strain rate had an accelerating effect on the crack propagation rate. In both materials two steps were found during cracking. The first one was characterized as intergranular attack assisted by stress due to an anodic dissolution process. This step is followed by a transition to a transgranular mode of propagation, which was considered as the 'true' stress corrosion cracking step. The intergranular attack is the rate-determining step due to the fact that the transgranular propagation rate is higher than the intergranular propagation rate. Several stress corrosion cracking mechanisms were analyzed to explain the transgranular cracking. The predictions

Transformational Leadership and Organizational Citizenship Behavior: A Meta-Analytic Test of Underlying Mechanisms.

Science.gov (United States)

Nohe, Christoph; Hertel, Guido

2017-01-01

Based on social exchange theory, we examined and contrasted attitudinal mediators (affective organizational commitment, job satisfaction) and relational mediators (trust in leader, leader-member exchange; LMX) of the positive relationship between transformational leadership and organizational citizenship behavior (OCB). Hypotheses were tested using meta-analytic path models with correlations from published meta-analyses (761 samples with 227,419 individuals overall). When testing single-mediator models, results supported our expectations that each of the mediators explained the relationship between transformational leadership and OCB. When testing a multi-mediator model, LMX was the strongest mediator. When testing a model with a latent attitudinal mechanism and a latent relational mechanism, the relational mechanism was the stronger mediator of the relationship between transformational leadership and OCB. Our findings help to better understand the underlying mechanisms of the relationship between transformational leadership and OCB.

Smad2 and Smad6 as predictors of overall survival in oral squamous cell carcinoma patients

Directory of Open Access Journals (Sweden)

Snitcovsky Igor

2010-05-01

Full Text Available Abstract Background To test if the expression of Smad1-8 mRNAs were predictive of survival in patients with oral squamous cell carcinoma (SCC. Patients and Methods We analyzed, prospectively, the expression of Smad1-8, by means of Ribonuclease Protection Assay in 48 primary, operable, oral SCC. In addition, 21 larynx, 10 oropharynx and 4 hypopharynx SCC and 65 matched adjacent mucosa, available for study, were also included. For survival analysis, patients were categorized as positive or negative for each Smad, according to median mRNA expression. We also performed real-time quantitative PCR (QRTPCR to asses the pattern of TGFβ1, TGFβ2, TGFβ3 in oral SCC. Results Our results showed that Smad2 and Smad6 mRNA expression were both associated with survival in Oral SCC patients. Cox Multivariate analysis revealed that Smad6 positivity and Smad2 negativity were both predictive of good prognosis for oral SCC patients, independent of lymph nodal status (P = 0.003 and P = 0.029, respectively. In addition, simultaneously Smad2- and Smad6+ oral SCC group of patients did not reach median overall survival (mOS whereas the mOS of Smad2+/Smad6- subgroup was 11.6 months (P = 0.004, univariate analysis. Regarding to TGFβ isoforms, we found that Smad2 mRNA and TGFβ1 mRNA were inversely correlated (p = 0.05, R = -0.33, and that seven of the eight TGFβ1+ patients were Smad2-. In larynx SCC, Smad7- patients did not reach mOS whereas mOS of Smad7+ patients were only 7.0 months (P = 0.04. No other correlations were found among Smad expression, clinico-pathological characteristics and survival in oral, larynx, hypopharynx, oropharynx or the entire head and neck SCC population. Conclusion Smad6 together with Smad2 may be prognostic factors, independent of nodal status in oral SCC after curative resection. The underlying mechanism which involves aberrant TGFβ signaling should be better clarified in the future.

Economic evaluation of maintenance strategies for steam generator tubes using probabilistic fracture mechanics and financial method

International Nuclear Information System (INIS)

Sagisaka, Mitsuyuki; Isobe, Yoshihiro; Yoshimura, Shinobu; Yagawa, Genki

2004-01-01

As an application of probabilistic fracture mechanics (PFM) and a financial method, risk-benefit analyses were performed for the purpose of optimizing maintenance activities of steam generator (SG) tubes used in pressurized water reactors (PWRs). Parameters such as in-service inspection (ISI) detection accuracy, ISI interval, sampling inspection, replacement of SGs and stress corrosion cracking (SCC) allowance operation were selected for sensitivity analyses. In the analysis of the operation introducing maintenance criteria, the effect of quantitative accuracy of the inspection was also taken into account. Although the analyses were mainly conducted for SG tubes made of Inconel 600 mill anneal (MA) materials, the analyses were also performed for SCC-resistant materials with making assumptions on their crack initiation probabilities and crack propagation laws. To justify whether or not it is worth while implementing the selected maintenance strategies in terms of an economic point of view, net present value (NPV) was calculated as an index which is one of the most fundamental financial indices for decision-making based on the discounted cash flow (DCF) method. (author)

Project Physics Tests 3, The Triumph of Mechanics.

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Harvard Univ., Cambridge, MA. Harvard Project Physics.

Test items relating to Project Physics Unit 3 are presented in this booklet. Included are 70 multiple-choice and 20 problem-and-essay questions. Concepts of mechanics are examined on energy, momentum, kinetic theory of gases, pulse analyses, "heat death," water waves, power, conservation laws, normal distribution, thermodynamic laws, and…

Assessment of the effects of surface preparation and coatings on the susceptibility of line pipe to stress-corrosion cracking

International Nuclear Information System (INIS)

Beavers, J.A.

1992-01-01

Objectives were to evaluate susceptibility of pipeline steel to SCC when coated with coal-tar enamel, fusion-bonded epoxy (FBE), and polyethylene tape coatings. The tests included standard cathodic disbondment tests, potential gradients beneath disbonded coatings, electrochemical measurements, and SCC tests. It was concluded that factors affecting relative SCC susceptibility of pipelines with different coatings are the disbonding resistance of the coating and the ability of the coating to pass cathodic protection (CP) current. FBE coated pipelines would be expected to exhibit good SCC resistance, since the FBE coating had high cathodic disbonding resistance and could pass CP current. Grit blasting at levels used at coating mills may be beneficial or detrimental to SCC susceptibility. Excellent correlation was found between th Almen strip deflection and change in SCC threshold stress. It appears to be beneficial to remove as much mill scale as possible, and a white surface finish probably should also be specified. 50 figs, 10 tabs

Neuropsychological mechanisms of Digit Symbol Substitution Test impairment in Asperger Disorder.

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Yoran-Hegesh, Roni; Kertzman, Semion; Vishne, Tali; Weizman, Abraham; Kotler, Moshe

2009-03-31

Our aim was to investigate the neurocognitive mechanisms recruited by adolescents with Asperger Disorder (AD), in comparison to controls, and to detect the underlying mechanisms during the complex information processing required for the performance of the Digit Symbol Substitution Test (DSST). Male adolescents (n=23; mean age 15.1+/-3.6 years) with a DSM-IV diagnosis of AD were compared with a normal male control group with similar demographic characteristics (n=43; mean age: 15.1+/-3.6 years). A computerized neurocognitive battery was administered and included: Inspection Time (IT), Finger Tapping Test (FTT), Simple Reaction Time (SRT), Choice Reaction Time (CRT), Digit Running task (DRT), Stroop test and Digit Symbol Substitution Test (DSST). Adolescents with AD performed significantly worse than controls on the DSST. This impaired DSST performance was related to cognitive mechanisms different from those employed by normal controls. Motor slowness and inability to deal with increased amounts of information affected the performance of the AD group, while shifting of attention was the limiting factor in the controls. Both groups were similarly dependent on response selection. This study demonstrated differences in performance in complex cognitive tasks between adolescents with AD and normal controls that may be related to differences in neurocognitive mechanisms underlying information processing. Future neuroimaging studies are needed to clarify the neural network involved in the differences in cognitive performance between AD subjects and normal controls.

The Performance test of Mechanical Sodium Pump with Water Environment

International Nuclear Information System (INIS)

Cho, Chungho; Kim, Jong-Man; Ko, Yung Joo; Jeong, Ji-Young; Kim, Jong-Bum; Ko, Bock Seong; Park, Sang Jun; Lee, Yoon Sang

2015-01-01

As contrasted with PWR(Pressurized light Water Reactor) using water as a coolant, sodium is used as a coolant in SFR because of its low melting temperature, high thermal conductivity, the high boiling temperature allowing the reactors to operate at ambient pressure, and low neutron absorption cross section which is required to achieve a high neutron flux. But, sodium is violently reactive with water or oxygen like the other alkali metal. So Very strict requirements are demanded to design and fabricate of sodium experimental facilities. Furthermore, performance testing in high temperature sodium environments is more expensive and time consuming and need an extra precautions because operating and maintaining of sodium experimental facilities are very difficult. The present paper describes performance test results of mechanical sodium pump with water which has been performed with some design changes using water test facility in SAM JIN Industrial Co. To compare the hydraulic characteristic of model pump with water and sodium, the performance test of model pump were performed using vender's experimental facility for mechanical sodium pump. To accommodate non-uniform thermal expansion and to secure the operability and the safety, the gap size of some parts of original model pump was modified. Performance tests of modified mechanical sodium pump with water were successfully performed. Water is therefore often selected as a surrogate test fluid because it is not only cheap, easily available and easy to handle but also its important hydraulic properties (density and kinematic viscosity) are very similar to that of the sodium. Normal practice to thoroughly test a design or component before applied or installed in reactor is important to ensure the safety and operability in the sodium-cooled fast reactor (SFR). So, in order to estimate the hydraulic behavior of the PHTS pump of DSFR (600 MWe Demonstraion SFR), the performance tests of the model pump such as performance

Mechanisms underlying the anti-androgenic effects of diethylhexyl phthalate in fetal rat testis

International Nuclear Information System (INIS)

Borch, Julie; Metzdorff, Stine Broeng; Vinggaard, Anne Marie; Brokken, Leon; Dalgaard, Majken

2006-01-01

Diethylhexyl phthalate (DEHP) is widely used as a plasticizer in consumer products and is known to disturb the development of the male reproductive system in rats. The mechanisms by which DEHP exerts these effects are not yet fully elucidated, though some of the effects are related to reduced fetal testosterone production. The present study investigated the effects of four different doses of DEHP on fetal testicular histopathology, testosterone production and expression of proteins and genes involved in steroid synthesis in fetal testes. Pregnant Wistar rats were gavaged from GD 7 to 21 with vehicle, 10, 30, 100 or 300 mg/kg bw/day of DEHP. In male fetuses examined at GD 21, testicular testosterone production ex vivo and testicular testosterone levels were reduced significantly at the highest dose. Histopathological effects on gonocytes were observed at 100 and 300 mg/kg bw/day, whereas Leydig cell effects were mainly seen at 300 mg/kg bw/day. Quantitative RT-PCR revealed reduced testicular mRNA expression of the steroidogenesis related factors SR-B1, StAR, PBR and P450scc. Additionally, we observed reduced mRNA expression of the nuclear receptor SF-1, which regulates certain steps in steroid synthesis, and reduced expression of the cryptorchidism-associated Insl-3. Immunohistochemistry showed clear reductions of StAR, PBR, P450scc and PPARγ protein levels in fetal Leydig cells, indicating that DEHP affects regulation of certain steps in cholesterol transport and steroid synthesis. The suppression of testosterone levels observed in phthalate-exposed fetal rats was likely caused by the low expression of these receptors and enzymes involved in steroidogenesis. It is conceivable that the observed effects of DEHP on the expression of nuclear receptors SF-1 and PPARγ are involved in the downregulation of steroidogenic factors and testosterone levels and thereby underlie the disturbed development of the male reproductive system

Control rod drive mechanism stator loss of coolant test

International Nuclear Information System (INIS)

Besel, L.; Ibatuan, R.

1977-04-01

This report documents the stator loss of coolant test conducted at HEDL on the lead unit Control Rod Drive Mechanism (CRDM) in February, 1977. The purpose of the test was to demonstrate scram capability of the CRDM with an uncooled stator and to obtain a time versus temperature curve of an uncooled stator under power. Brief descriptions of the test, hardware used, and results obtained are presented in the report. The test demonstrated that the CRDM could be successfully scrammed with no anomalies in both the two-phase and three-phase stator winding hold conditions after the respective equilibrium stator temperatures had been obtained with no stator coolant

Self-compacting concrete with sugarcane bagasse ash – ground blast furnace slag blended cement: fresh properties

Science.gov (United States)

Le, Duc-Hien; Sheen, Yeong-Nain; Ngoc-Tra Lam, My

2018-04-01

In this investigation, major properties in fresh state of self-compacting concrete (SCC) developed from sugarcane bagasse ash and granulated blast furnace slag as supplementary cementitious materials were examined through an experimental work. There were four mix groups (S0, BA10, BA20, and BA30) containing different cement replacing levels; and totally, 12 SCC mixtures and one control mixture were provided for the test. Fresh properties of the proposed SCC were evaluated through measurement of the density, slump, slump-flow, V-funnel test, T500 slump, Box-test, and setting time. The testing results indicated that replacing either SBA and/or BFS to OPC in SCC mixtures led to lower density, lesser flowability, and longer hardening times.

Overexpression of the steroidogenic enzyme cytochrome P450 side chain cleavage in the ventral tegmental area increases 3α,5α-THP and reduces long-term operant ethanol self-administration.

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Cook, Jason B; Werner, David F; Maldonado-Devincci, Antoniette M; Leonard, Maggie N; Fisher, Kristen R; O'Buckley, Todd K; Porcu, Patrizia; McCown, Thomas J; Besheer, Joyce; Hodge, Clyde W; Morrow, A Leslie

2014-04-23

Neuroactive steroids are endogenous neuromodulators capable of altering neuronal activity and behavior. In rodents, systemic administration of endogenous or synthetic neuroactive steroids reduces ethanol self-administration. We hypothesized this effect arises from actions within mesolimbic brain regions that we targeted by viral gene delivery. Cytochrome P450 side chain cleavage (P450scc) converts cholesterol to pregnenolone, the rate-limiting enzymatic reaction in neurosteroidogenesis. Therefore, we constructed a recombinant adeno-associated serotype 2 viral vector (rAAV2), which drives P450scc expression and neuroactive steroid synthesis. The P450scc-expressing vector (rAAV2-P450scc) or control GFP-expressing vector (rAAV2-GFP) were injected bilaterally into the ventral tegmental area (VTA) or nucleus accumbens (NAc) of alcohol preferring (P) rats trained to self-administer ethanol. P450scc overexpression in the VTA significantly reduced ethanol self-administration by 20% over the 3 week test period. P450scc overexpression in the NAc, however, did not alter ethanol self-administration. Locomotor activity was unaltered by vector administration to either region. P450scc overexpression produced a 36% increase in (3α,5α)-3-hydroxypregnan-20-one (3α,5α-THP, allopregnanolone)-positive cells in the VTA, but did not increase 3α,5α-THP immunoreactivity in NAc. These results suggest that P450scc overexpression and the resultant increase of 3α,5α-THP-positive cells in the VTA reduces ethanol reinforcement. 3α,5α-THP is localized to neurons in the VTA, including tyrosine hydroxylase neurons, but not astrocytes. Overall, the results demonstrate that using gene delivery to modulate neuroactive steroids shows promise for examining the neuronal mechanisms of moderate ethanol drinking, which could be extended to other behavioral paradigms and neuropsychiatric pathology.

Studies on sulfate attack: Mechanisms, test methods, and modeling

Science.gov (United States)

Santhanam, Manu

The objective of this research study was to investigate various issues pertaining to the mechanism, testing methods, and modeling of sulfate attack in concrete. The study was divided into the following segments: (1) effect of gypsum formation on the expansion of mortars, (2) attack by the magnesium ion, (3) sulfate attack in the presence of chloride ions---differentiating seawater and groundwater attack, (4) use of admixtures to mitigate sulfate attack---entrained air, sodium citrate, silica fume, and metakaolin, (5) effects of temperature and concentration of the attack solution, (6) development of new test methods using concrete specimens, and (7) modeling of the sulfate attack phenomenon. Mortar specimens using portland cement (PC) and tricalcium silicate (C 3S), with or without mineral admixtures, were prepared and immersed in different sulfate solutions. In addition to this, portland cement concrete specimens were also prepared and subjected to complete and partial immersion in sulfate solutions. Physical measurements, chemical analyses and microstructural studies were performed periodically on the specimens. Gypsum formation was seen to cause expansion of the C3S mortar specimens. Statistical analyses of the data also indicated that the quantity of gypsum was the most significant factor controlling the expansion of mortar bars. The attack by magnesium ion was found to drive the reaction towards the formation of brucite. Decalcification of the C-S-H and its subsequent conversion to the non-cementitious M-S-H was identified as the mechanism of destruction in magnesium sulfate attack. Mineral admixtures were beneficial in combating sodium sulfate attack, while reducing the resistance to magnesium sulfate attack. Air entrainment did not change the measured physical properties, but reduced the visible distress of the mortars. Sodium citrate caused a substantial reduction in the rate of damage of the mortars due to its retarding effect. Temperature and

Design and fabrication of a cryostat for low temperature mechanical testing for the Mechanical and Materials Engineering group at CERN

CERN Document Server

Aviles Santillana, I; Gerardin, A; Guinchard, M; Langeslag, S A E; Sgobba, S

2015-01-01

Mechanical testing of materials at low temperatures is one of the cornerstones of the Mechanical and Materials Engineering (MME) group at CERN. A long tradition of more than 20 years and a unique know - how of such tests has been developed with an 18 kN double-walled cryostat. Large campaigns of material qualification have been carried out and the mechanical behaviour of materials at 4 K has been vastly studied in sub - size samples for projects like LEP, LHC and its experiments. With the aim of assessing the mechanical properties of materials of higher strength and/or issued from heavy gauge products for which testing standardized specimens of larger cross section might be more adapted, a new 100 kN cryostat capable of hosting different shapes of normalized samples has been carefully designed and fabricated inhouse together with the associated tooling and measurement instrumentation. It has been conceived to be able to adapt to different test frames both dynamic and static, which will be of paramount importa...

Mechanical testing of PHWR components at different fabrication stages

International Nuclear Information System (INIS)

Saibaba, N.

2007-01-01

Zirconium alloys are extensively used for reactor structural and cladding components for PHWRs and BWRs due to their low neutron absorption cross-section, corrosion resistance to high temperature aqueous environments, adequate mechanical properties and resistance to radiation damage. The coolant tube fabrication route consists of a series of intermediate process steps. The working parameters of each process have a definite bearing on the final properties of these tubes. In order to ascertain the effect of these parameters, mechanical testing is carried out at intermediate stage of coolant tube fabrication. The mechanical properties of the products can be correlated with process parameters and reflect the quality of the product to a great extent. These properties at intermediate stages can serve as process controlling parameters. This paper discusses the correlation of mechanical properties of pressure tubes between the intermediate stage and final stage. The effect of process parameters like annealing temperature, honing, sand blasting pressure and eccentricity on the final mechanical properties was highlighted. (author)

Stress-corrosion cracking properties of candidate fuel cladding alloys for the Canadian SCWR: a summary of literature data and recent test results