Low cycle fatigue properties of CLAM steel at 823 K

Energy Technology Data Exchange (ETDEWEB)

Hu, Xue [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049 (China); Huang, Lixin [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Yan, Wei; Wang, Wei [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Sha, Wei [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast, Belfast BT9 5AG (United Kingdom); Shan, Yiyin, E-mail: yyshan@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Yang, Ke, E-mail: kyang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)

2014-09-08

China Low Activation Martensitic (CLAM) steel is considered to be the main candidate material for the first wall components of future fusion reactors in China. In this paper, the low cycle fatigue (LCF) behavior of CLAM steel is studied under fully reversed tension–compression loading at 823 K in air. Total strain amplitude was controlled from 0.14% to 1.8% with a constant strain rate of 2.4×10{sup −3} s{sup −1}. The corresponding plastic strain amplitude ranged from 0.023% to 1.613%. The CLAM steel displayed continuous softening to failure at 823 K. The relationship between strain, stress and fatigue life was obtained using the parameters obtained from fatigue tests. The LCF properties of CLAM steel at 823 K followed Coffin–Manson relationship. Furthermore, irregular serration was observed on the stress–strain hysteresis loops of CLAM steel tested with the total strain amplitude of 0.45–1.8%, which was attributed to the dynamic strain aging (DSA) effect. During continuous cyclic deformation, the microstructure and precipitate distribution of CLAM steel changed gradually. Many tempered martensitic laths were decomposed into subgrains, and the size and number of M{sub 23}C{sub 6} carbide and MX carbonitride precipitates decreased with the increase of total strain amplitude. The response cyclic stress promoted the recovery of martensitic lath, while the thermal activation mainly played an important role on the growth of precipitates in CLAM steel at 823 K. In order to have a better understanding of high-temperature LCF behavior, the potential mechanisms controlling stress–strain response, DSA phenomenon and microstructure changes have also been evaluated.

Fatigue Life of Stainless Steel in PWR Environments with Strain Holding

Energy Technology Data Exchange (ETDEWEB)

Kim, Taesoon; Kim, Kyuhyung [KHNP CRI, Daejeon (Korea, Republic of); Seo, Myeonggyu; Jang, Changheui [KAIST, Daejeon (Korea, Republic of)

2016-10-15

Many components and structures of nuclear power plants are exposed to the water chemistry conditions during the operation. Recently, as design life of nuclear power plant is expanded over 60 years, the environmentally assisted fatigue (EAF) due to these water chemistry conditions has been considered as one of the important damage mechanisms of the safety class 1 components. Therefore, many studies to evaluate the effect of light water reactor (LWR) coolant environments on fatigue life of materials have been conducted. Many EAF test results including Argonne National Laboratory’s consistently indicated the substantial reduction of fatigue life in the light water reactor environments. However, there is a discrepancy between laboratory test data and plant operating experience regarding the effects of environment on fatigue: while laboratory test data suggest huge accumulation of fatigue damage, very limited experience of cracking caused by the low cycle fatigue in light water reactor. These hold-time effect tests are preformed to characterize the effects of strain holding on the fatigue life of austenitic stainless steels in PWR environments in comparison with the existing fixed strain rate results. Low cycle fatigue life tests were conducted for the type 316 stainless steel in 310℃ air and PWR environments with triangular strain. In agreement with the previous reports, the LCF life was reduced in PWR environments. Also for the slower strain rate, the reduction of LCF life was greater than the faster strain rate. The LCF test conditions for the hold-time effects were determined by the references and consideration of actual plant transient. To simulate the heat-up and cooldown transient, sub-peak strain holding during the down-hill of strain amplitude was chosen instead of peak strain holding which used in the previous researches.

Strain-controlled low cycle fatigue properties of a rare-earth containing ME20 magnesium alloy

Energy Technology Data Exchange (ETDEWEB)

Mirza, F.A., E-mail: f4mirza@ryerson.ca [Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3 (Canada); Wang, K.; Bhole, S.D.; Friedman, J.; Chen, D.L. [Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3 (Canada); Ni, D.R.; Xiao, B.L. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Ma, Z.Y., E-mail: zyma@imr.ac.cn [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)

2016-04-20

The present study was aimed to evaluate the strain-controlled cyclic deformation characteristics and low cycle fatigue (LCF) life of a low (~0.3 wt%) Ce-containing ME20-H112 magnesium alloy. The alloy contained equiaxed grains with ellipsoidal particles containing Mg and Ce (Mg{sub 12}Ce), and exhibited a relatively weak basal texture. Unlike the high rare earth (RE)-containing magnesium alloy, the ME20M-H112 alloy exhibited asymmetrical hysteresis loops somewhat similar to the RE-free extruded Mg alloys due to the presence of twinning-detwinning activities during cyclic deformation. While cyclic stabilization was barely achieved even at the lower strain amplitudes, cyclic softening was the predominant characteristics at most strain amplitudes. The ME20M-H112 alloy showed basically an equivalent fatigue life to that of the RE-free extruded Mg alloys, which could be described by the Coffin-Manson law and Basquin's equation. Fatigue crack was observed to initiate from the near-surface imperfections, and in contrast to the typical fatigue striations, the present alloy showed some shallow dimples along with some fractions of quasi-cleavage features in the crack propagation area.

Stress-strain time-dependent behavior of A356.0 aluminum alloy subjected to cyclic thermal and mechanical loadings

Science.gov (United States)

Farrahi, G. H.; Ghodrati, M.; Azadi, M.; Rezvani Rad, M.

2014-08-01

This article presents the cyclic behavior of the A356.0 aluminum alloy under low-cycle fatigue (or isothermal) and thermo-mechanical fatigue loadings. Since the thermo-mechanical fatigue (TMF) test is time consuming and has high costs in comparison to low-cycle fatigue (LCF) tests, the purpose of this research is to use LCF test results to predict the TMF behavior of the material. A time-independent model, considering the combined nonlinear isotropic/kinematic hardening law, was used to predict the TMF behavior of the material. Material constants of this model were calibrated based on room-temperature and high-temperature low-cycle fatigue tests. The nonlinear isotropic/kinematic hardening law could accurately estimate the stress-strain hysteresis loop for the LCF condition; however, for the out-of-phase TMF, the condition could not predict properly the stress value due to the strain rate effect. Therefore, a two-layer visco-plastic model and also the Johnson-Cook law were applied to improve the estimation of the stress-strain hysteresis loop. Related finite element results based on the two-layer visco-plastic model demonstrated a good agreement with experimental TMF data of the A356.0 alloy.

Low cycle fatigue behaviour of Ti-6Al-5Zr-0.5Mo-0.25Si alloy at room temperature

International Nuclear Information System (INIS)

Nag, Anil Kumar; Praveen, K.V.U.; Singh, Vakil

2006-01-01

Low cycle fatigue (LCF) behaviour of the near α titanium alloy, Ti-6Al-5Zr-0.5Mo-0.25Si (LT26A), was investigated in the (α+ β) as well as β treated conditions at room temperature. LCF tests were carried out under total strain controlled mode in the range of Δε t /2: from ± 0.60% to ± 1.40%. The alloy shows cyclic softening in both the conditions. Also it exhibits dual slope Coffin-Manson (C-M) relationship in both the treated conditions. (author)

Toward enhanced hydrogen generation from water using oxygen permeating LCF membranes

KAUST Repository

Wu, Xiao-Yu

2015-01-01

© the Owner Societies. Hydrogen production from water thermolysis can be enhanced by the use of perovskite-type mixed ionic and electronic conducting (MIEC) membranes, through which oxygen permeation is driven by a chemical potential gradient. In this work, water thermolysis experiments were performed using 0.9 mm thick La0.9Ca0.1FeO3-δ (LCF-91) perovskite membranes at 990 °C in a lab-scale button-cell reactor. We examined the effects of the operating conditions such as the gas species concentrations and flow rates on the feed and sweep sides on the water thermolysis rate and oxygen flux. A single step reaction mechanism is proposed for surface reactions, and three-resistance permeation models are derived. Results show that water thermolysis is facilitated by the LCF-91 membrane especially when a fuel is added to the sweep gas. Increasing the gas flow rate and water concentration on the feed side or the hydrogen concentration on the sweep side enhances the hydrogen production rate. In this work, hydrogen is used as the fuel by construction, so that a single-step surface reaction mechanism can be developed and water thermolysis rate parameters can be derived. Both surface reaction rate parameters for oxygen incorporation/dissociation and hydrogen-oxygen reactions are fitted at 990 °C. We compare the oxygen fluxes in water thermolysis and air separation experiments, and identify different limiting steps in the processes involving various oxygen sources and sweep gases for this 0.9 mm thick LCF-91 membrane. In the air feed-inert sweep case, the bulk diffusion and sweep side surface reaction are the two limiting steps. In the water feed-inert sweep case, surface reaction on the feed side dominates the oxygen permeation process. Yet in the water feed-fuel sweep case, surface reactions on both the feed and sweep sides are rate determining when hydrogen concentration in the sweep side is in the range of 1-5 vol%. Furthermore, long term studies show that the surface

Tuning Low Cycle Fatigue Properties of Cu-Be-Co-Ni Alloy by Precipitation Design

Directory of Open Access Journals (Sweden)

Yanchuan Tang

2018-06-01

Full Text Available As material for key parts applied in the aerospace field, the Cu-Be-Co-Ni alloy sustains cyclic plastic deformation in service, resulting in the low cycle fatigue (LCF failure. The LCF behaviors are closely related to the precipitation states of the alloy, but the specific relevance is still unknown. To provide reasonable regulation of the LCF properties for various service conditions, the effect of precipitation states on the LCF behaviors of the alloy was investigated. It is found that the alloy composed fully of non-shearable γ′ precipitates has higher fatigue crack initiation resistance, resulting in a longer fatigue life under LCF process with low total strain amplitude. The alloy with fine shearable γ′I precipitates presents higher fatigue crack propagation resistance, leading to a longer fatigue life under LCF process with high total strain amplitude. The cyclic stress response behavior of the alloy depends on the competition between the kinematic hardening and isotropic softening. The fine shearable γ′I precipitates retard the decrease of effective stress during cyclic loading, causing cyclic hardening of the alloy. The present work would help to design reasonable precipitation states of the alloy for various cyclic loading conditions to guarantee its safety in service.

The UK's Levy Control Framework for renewable electricity support: Effects and significance

International Nuclear Information System (INIS)

Lockwood, Matthew

2016-01-01

There is a long-standing debate over price vs. quantity approaches to supporting the deployment of renewable electricity technologies. In the context of a recent shift from quantity to price-based support, the UK has also introduced a new form of budgetary framework, the Levy Control Framework (LCF). The introduction of the LCF has been very important for investors but has received relatively little attention in the academic literature. The paper gives an overview of the LCF, explores its effects on renewables policy, on consumers and on investor confidence arguing that an unintended consequence of its introduction has been to increase uncertainty, through interactions with underlying support mechanisms. A number of problems with the current scope and design of the LCF are noted. It is argued that the LCF is best understood as aimed at avoiding a political backlash against renewable support policy in a context where the benefits of such policy are concentrated economically and socially. The paper concludes by placing the LCF within a wider context of a shift towards greater budgetary control over renewable energy support policy across European countries. - Highlights: • Gives an description of the Levy Control Framework. • Analyses the effects of the LCF on UK renewable policy. • Reviews possible purposes of the LCF. • Evaluates the effects of the LCF on consumers and investors. • Places the LCF in context of greater cost control over renewables across the EU.

Cyclic Deformation and Fatigue Behaviors of Alloy 617 Base Metal and Weldments at 900℃ for VHTR Applications

Energy Technology Data Exchange (ETDEWEB)

Kim, Seon Jin; Kim, Byung Tak; Dewa, Rando T.; Hwang, Jeong Jun; Kim, Tae Su [Pukyong National Univ., Busan (Korea, Republic of); Kim, Woo Gon; Kim, Eung Seon [KAERI, Daejeon (Korea, Republic of)

2016-05-15

An analysis of cyclic deformation can contribute to a deeper understanding of the fatigue fracture mechanisms as well as to improvements in the design and application of VHTR system. However, the studies associated with cyclic deformation and low cycle fatigue (LCF) properties of Alloy 617 have focused mainly on the base metal, with little attention given to the weldments. Totemeier studied on high-temperature creep-fatigue of Alloy 617 base metal and weldments. Current research activities at PKNU and KAERI focus on the study of cyclic deformation and LCF behaviors of Alloy 617 base metal (BM) and weldments (WM) specimens were machined from GTAW buttwelded plates at very high-temperature of 900℃. In this work, the cyclic deformation characteristics and fatigue behaviors of Alloy 617 BM and WM are studied and discussed with respect to LCF. In this paper, cyclic deformation and low cycle fatigue behaviors of Alloy 617 base metal and weldments was evaluated using strain-controlled LCF tests at 900℃for 0.6% total strain range. Results of the current experiments can be concluded; The WM specimen has shown a higher cyclic stress response than the BM specimen. The fatigue life of WM specimen was reduced relative to that of BM specimen.

Cyclic deformation and fatigue behaviors of Hadfield manganese steel

Energy Technology Data Exchange (ETDEWEB)

Kang, J. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Zhang, F.C., E-mail: zfc@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Long, X.Y. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Lv, B. [School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004 (China)

2014-01-03

The cyclic deformation characteristics and fatigue behaviors of Hadfield manganese steel have been investigated by means of its ability to memorize strain and stress history. Detailed studies were performed on the strain-controlled low cycle fatigue (LCF) and stress-controlled high cycle fatigue (HCF). Initial cyclic hardening to saturation or peak stress followed by softening to fracture occurred in LCF. Internal stress made the dominant contribution to the fatigue crack propagation until failure. Effective stress evolution revealed the existence of C–Mn clusters with short-range ordering in Hadfield manganese steel and demonstrated that the interaction between C atoms in the C–Mn cluster and dislocation was essential for its cyclic hardening. The developing/developed dislocation cells and stacking faults were the main cyclic deformation microstructures on the fractured sample surface in LCF and HCF, which manifested that fatigue failure behavior of Hadfield manganese steel was induced by plastic deformation during strain-controlled or stress-controlled testing.

ANOVA parameters influence in LCF experimental data and simulation results

Directory of Open Access Journals (Sweden)

Vercelli A.

2010-06-01

Full Text Available The virtual design of components undergoing thermo mechanical fatigue (TMF and plastic strains is usually run in many phases. The numerical finite element method gives a useful instrument which becomes increasingly effective as the geometrical and numerical modelling gets more accurate. The constitutive model definition plays an important role in the effectiveness of the numerical simulation [1, 2] as, for example, shown in Figure 1. In this picture it is shown how a good cyclic plasticity constitutive model can simulate a cyclic load experiment. The component life estimation is the subsequent phase and it needs complex damage and life estimation models [3-5] which take into account of several parameters and phenomena contributing to damage and life duration. The calibration of these constitutive and damage models requires an accurate testing activity. In the present paper the main topic of the research activity is to investigate whether the parameters, which result to be influent in the experimental activity, influence the numerical simulations, thus defining the effectiveness of the models in taking into account of all the phenomena actually influencing the life of the component. To obtain this aim a procedure to tune the parameters needed to estimate the life of mechanical components undergoing TMF and plastic strains is presented for commercial steel. This procedure aims to be easy and to allow calibrating both material constitutive model (for the numerical structural simulation and the damage and life model (for life assessment. The procedure has been applied to specimens. The experimental activity has been developed on three sets of tests run at several temperatures: static tests, high cycle fatigue (HCF tests, low cycle fatigue (LCF tests. The numerical structural FEM simulations have been run on a commercial non linear solver, ABAQUS®6.8. The simulations replied the experimental tests. The stress, strain, thermal results from the thermo

Challenges in high temperature low cycle fatigue testing of metallic materials

International Nuclear Information System (INIS)

Sandhya, R.; Valsan, M.; Bhanu Sankara Rao, K.

2007-01-01

The evaluation of the high strain Low Cycle Fatigue properties of structural materials is an involved and complicated procedure requiring skill and diligence from the experimentalist. This presentation describes the various testing methods to evaluate the LCF properties of structural materials, the complexities involved and some solutions to exacting requirements, not covered by the testing procedure standards. The basic components of servo-hydraulic fatigue testing machines is described, as are the calibration and maintenance procedures. Results of LCF tests conducted at the authors' laboratory on AISI 316L(N) stainless steel and Mod.9Cr-1Mo ferritic steel are described. The complications in total strain controlled testing of weld joints is brought out and soft zone development in Mod. 9Cr-1Mo ferritic steel is described. The special requirements for testing in environmental chambers is a challenging task. In-house chambers, designed to carry out testing in dynamic sodium environment is highlighted. These chambers have provision to accommodate extensometers for strain measurements, and also house all the safety instrumentation needed to carry out to mechanical testing in dynamic sodium environment. The variation of LCF results as a function of specimen geometry is examined. The various failure criteria adopted by laboratories in different countries are also touched upon. (author)

Possible in-lattice confinement fusion (LCF). Dynamic application of atomic and nuclear data

International Nuclear Information System (INIS)

Kawarasaki, Yuuki

1995-01-01

New scheme of a nuclear fusion reactor system is proposed, the basic concept of which comes from ingenious combination of hitherto developed techniques and verified facts; 1) so-called cold fusion (CF), 2) plasma of both magnetic confinement fusion (MCF) and inertial confinement fusion (ICF), and 3) accelerator-based D-T(D) neutron source. Details of the LCF reactor physics require dynamics of atomic data as well as nuclear data; interaction of ions with matters in solid and the problems of radiation damage. (author)

Local strain in front of cracks in the case of creep fatigue

International Nuclear Information System (INIS)

Rie Kyongtschong; Olfe, J.

1993-01-01

In-situ measurements of strain fields in front of cracks were performed for high temperature Low Cycle Fatigue (LCF) with different hold times by means of a grid method. The tests were carried out on the austenitic stainless steel 304 L and the ferritic steel X22 CrMoV 12 1. Simultaneous observation of crack growth leads to a correlation between crack growth and local strain. The interaction of creep and fatigue related to strain concentration at the crackk tip and crack growth was discussed. A model is proposed which is based on the formation of cavities on grain boundaries. (orig.) [de

High temperature low cycle fatigue behavior of a directionally solidified Ni-base superalloy DZ951

International Nuclear Information System (INIS)

Chu Zhaokuang; Yu Jinjiang; Sun Xiaofeng; Guan Hengrong; Hu Zhuangqi

2008-01-01

Total strain-controlled low cycle fatigue (LCF) tests were performed at a temperature range from 700 to 900 deg. C in ambient air condition on a directionally solidified Ni-base superalloy DZ951. The fatigue life of DZ951 alloy does not monotonously decrease with increasing temperature, but exhibits a strong dependence on the total strain range. The dislocation characteristics and failed surface observation were evaluated through transmission electron microscopy and scanning electron microscopy. The alloy exhibits cyclic hardening, softening or cyclic stability as a whole, which is dependent on the testing temperature and total strain range. At 700 deg. C, the cyclic plastic deformation process is the main cause of fatigue failure. At 900 deg. C, the failure mostly results from combined fatigue and creep damage under total strain range from 0.6 to 1.2% and the reduction in fatigue life can be taken as the cause of oxidation, creep and cyclic plastic deformation under total strain range of 0.5%

Fatigue and fracture behavior of low alloy ferritic forged steels

International Nuclear Information System (INIS)

Chaudhry, V.; Sharma, A.K.; Muktibodh, U.C.; Borwankar, Neeraj; Singh, D.K.; Srinivasan, K.N.; Kulkarni, R.G.

2016-01-01

Low alloy ferritic steels are widely used in nuclear industry for the construction of pressure vessels. Pressure vessel forged low alloy steels 20MnMoNi55 (modified) have been developed indigenously. Experiments have been carried out to study the Low Cycle Fatigue (LCF) and fracture behavior of these forged steels. Fully reversed strain controlled LCF testing at room temperature and at 350 °C has been carried out at a constant strain rate, and for different axial strain amplitude levels. LCF material behavior has been studied from cyclic stress-strain responses and the strain-life relationships. Fracture behavior of the steel has been studied based on tests carried out for crack growth rate and fracture toughness (J-R curve). Further, responses of fatigue crack growth rate tests have been compared with the rate evaluated from fatigue precracking carried out for fracture toughness (J-R) tests. Fractography of the samples have been carried out to reveal dominant damage mechanisms in crack propagation and fracture. The fatigue and fracture properties of indigenously developed low alloy steel 20MnMoNi55 (modified) steels are comparable with similar class of steels. (author)

One- and multistage total strain and stress-controlled fatigue tests with a steel of type 42 CrMo 4 subject to varied residual and mean stress loading. Final report

International Nuclear Information System (INIS)

Macherauch, E.; Schulze, V.

1995-01-01

Work under this research project covered tests with the quenched and tempered steel 42 CrMo 4 to which one- and two-stage tension-compression fatigue stresses were applied with varying mean loads, under conditions of nominal stress and total strain control. Shot peening was used to induce various microstructural conditions in the material at the surface and near below. Softening in the material was observed to be a continuous process, and the steel showed no stabilised, cyclic deformation behaviour. The cyclic stress-strain curve measured with equal stress amplitudes and total strain control applied shows higher plastic strain amplitudes than that measured with nominal stresses. The fatigue behaviour under two-stage loading depends on the chosen sequence of loads applied, the testing periods, and the overall testing procedure, so that there is no way of deriving data for two-stage testing procedures from single-stage test results. (orig.) [de

High temperature fatigue behaviour of intermetallics

Indian Academy of Sciences (India)

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

The effect of processing route on strain-controlled low cycle fatigue (LCF) life of binary ..... the once regarding close control of composition, control and reproduction of ... inverse effect of temperature on fatigue life seen in tests conducted in air.

Ratcheting and low cycle fatigue behavior of SA333 steel and their life prediction

International Nuclear Information System (INIS)

Paul, Surajit Kumar; Sivaprasad, S.; Dhar, S.; Tarafder, S.

2010-01-01

Ratcheting and low cycle fatigue (LCF) experiments have been conducted at 25 o C temperature in laboratory environment under different loading conditions. SA333 steel exhibits cyclic hardening throughout its life during LCF. It is found that ratcheting strain increases with both increasing mean stress and stress amplitude. It has also been noticed that plastic strain amplitude and plastic strain energy decrease with increase in mean stress at constant stress amplitude. Ratcheting and LCF life in the range of 10 2 -10 5 cycles have been predicted with the help of a mean stress-based fatigue lifing equation.

Effect of creep and oxidation on reduced fatigue life of Ni-based alloy 617 at 850 °C

Energy Technology Data Exchange (ETDEWEB)

Chen, Xiang, E-mail: chenx@ornl.gov [Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, 104 South Wright Street, Urbana, IL 61801 (United States); Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831 (United States); Yang, Zhiqing [Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831 (United States); Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Sokolov, Mikhail A.; Erdman, Donald L. [Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831 (United States); Mo, Kun; Stubbins, James F. [Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, 104 South Wright Street, Urbana, IL 61801 (United States)

2014-01-15

Low cycle fatigue (LCF) and creep–fatigue testing of Ni-based alloy 617 was carried out at 850 °C. Compared with its LCF life, the material’s creep–fatigue life decreases to different extents depending on test conditions. To elucidate the microstructure-fatigue property relationship for alloy 617 and the effect of creep and oxidation on its fatigue life, systematic microstructural investigations were carried out using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and electron backscatter diffraction (EBSD). In LCF tests, as the total strain range increased, deformations concentrated near high angle grain boundaries (HAGBs). The strain hold period in the creep–fatigue tests introduced additional creep damage to the material, which revealed the detrimental effect of the strain hold time on the material fatigue life in two ways. First, the strain hold time enhanced the localized deformation near HAGBs, resulting in the promotion of intergranular cracking of alloy 617. Second, the strain hold time encouraged grain boundary sliding, which resulted in interior intergranular cracking of the material. Oxidation accelerated the initiation of intergranular cracking in alloy 617. In the crack propagation stage, if oxidation was promoted and the cyclic oxidation damage was greater than the fatigue damage, oxidation-assisted intergranular crack growth resulted in a significant reduction in the material’s fatigue life.

A low cycle fatigue model for low carbon manganese steel including the effect of dynamic strain aging

Energy Technology Data Exchange (ETDEWEB)

Huang, Zhi Yong, E-mail: huangzy@scu.edu.cn [Sichuan University, School of Aeronautics and Astronautics, No.29 Jiuyanqiao Wangjiang Road, Chengdu 610064 (China); Wagner, Danièle [Université Paris Ouest Nanterre La Défense (France); Wang, Qing Yuan; Khan, Muhammad Kashif [Sichuan University, School of Aeronautics and Astronautics, No.29 Jiuyanqiao Wangjiang Road, Chengdu 610064 (China); Chaboche, Jean–Louis [ONERA, DMSM, 29 avenue de la Division Lecerc, F-92320, Chatillon (France)

2016-01-27

Carbon–manganese steel A48 (French standards) is used in steam generator pipes of the nuclear power plant where it is subjected to the cyclic thermal load. The Dynamic Strain Aging (DSA) influences the mechanical behavior of the steel in low cycle fatigue (LCF) at favorable temperature and strain rate. The peak stress of A48 steel experiences hardening–softening–hardening (HSH) evolution at 200 °C and 0.4% s{sup −1} strain rate in fatigue loading. In this study, isotropic and kinematic hardening rules with DSA effect have been modified. The HSH evolution of cyclic stress associated with cumulative plastic deformation has also been estimated.

Job strain among blue-collar and white-collar employees as a determinant of total mortality: a 28-year population-based follow-up

Science.gov (United States)

Seitsamo, Jorma; von Bonsdorff, Monika E; Ilmarinen, Juhani; Nygård, Clas-Håkan; Rantanen, Taina

2012-01-01

Objectives To investigate the effect of job demand, job control and job strain on total mortality among white-collar and blue-collar employees working in the public sector. Design 28-year prospective population-based follow-up. Setting Several municipals in Finland. Participants 5731 public sector employees from the Finnish Longitudinal Study on Municipal Employees Study aged 44–58 years at baseline. Outcomes Total mortality from 1981 to 2009 among individuals with complete data on job strain in midlife, categorised according to job demand and job control: high job strain (high job demands and low job control), active job (high job demand and high job control), passive job (low job demand and low job control) and low job strain (low job demand and high job control). Results 1836 persons died during the follow-up. Low job control among men increased (age-adjusted HR 1.26, 95% CI 1.12 to 1.42) and high job demand among women decreased the risk for total mortality HR 0.82 (95% CI 0.71 to 0.95). Adjustment for occupational group, lifestyle and health factors attenuated the association for men. In the analyses stratified by occupational group, high job strain increased the risk of mortality among white-collar men (HR 1.52, 95% CI 1.09 to 2.13) and passive job among blue-collar men (HR 1.28, 95% CI 1.05 to 1.47) compared with men with low job strain. Adjustment for lifestyle and health factors attenuated the risks. Among white-collar women having an active job decreased the risk for mortality (HR 0.78, 95% CI 0.60 to 1.00). Conclusion The impact of job strain on mortality was different according to gender and occupational group among middle-aged public sector employees. PMID:22422919

Role of butter layer in low-cycle fatigue behavior of modified 9Cr and CrMoV dissimilar rotor welded joint

International Nuclear Information System (INIS)

Wu, Qingjun; Lu, Fenggui; Cui, Haichao; Liu, Xia; Wang, Peng; Tang, Xinhua

2014-01-01

Highlights: • Modified 9Cr–CrMoV dissimilar turbine rotor was successfully welded by NG-SAW. • LCF properties of both welded joints were approximate at smaller strain amplitude. • Tempered martensite with amounts of carbides in HAZ contributed to weakest zones. • Matched BL determined LCF properties of whole joint for dissimilar welded rotor. - Abstract: The present work aims at studying the role of butter layer (BL) in low-cycle fatigue (LCF) behavior of modified 9Cr steel and CrMoV steel dissimilar welded joint. The significant difference of the chemical composition of base metals (BMs) makes it a challenge to achieve sound welded joint. Therefore, buttering was considered to obtain a transition layer between the dissimilar steels. The LCF tests of two kinds of specimens without and with butter layer were performed applying strain-controlled cyclic load with different axial strain amplitudes. The test results indicated that the number of cycles at higher strain amplitudes of welded joint without butter layer was greatly higher than that of the joint with butter layer, while the fatigue lifetime to crack initiation (2N f ) became closer to each other at low and middle strain amplitudes. The failure was in the tempered heat affected zone (HAZ) at the CrMoV side for specimens without BL, while the fracture occurred at the tempered HAZ in the BL for specimens with BL. The microstructure details of BM, BL, HAZ and weld metals (WMs) were revealed by optical microscopy (OM). It was found that the tempered martensite was major microstructure for welded joint and much more carbides were observed in tempered HAZ than other parts due to the repeated tempering. Microhardness test indicated a softest zone existing tempered HAZ of BL and also there was a softer zone in tempered HAZ at the CrMoV side due to repeated tempering during welding and post weld heat treatment (PWHT). And scanning electron microscopy (SEM) was applied to observe the fractography. It was

Low cycle fatigue design data for India-specific reduced activation ferritic-martensitic (IN-RAFM) steel

Energy Technology Data Exchange (ETDEWEB)

Mariappan, K.; Shankar, Vani, E-mail: vani@igcar.gov.in; Sandhya, R.; Laha, K.

2016-03-15

Highlights: • Generation of first set of experimental data related to LCF performance of the commercial heat of IN-RAFM steel. • Analysis of cyclic behavior from the perspective of both design and material characteristics. • Various correction factors to account for various plastic strain accumulations, change in Poisson’s ratio and asymmetry of loadings. • Low cycle fatigue design parameters and correction factor values were comparable with P91 steel as reported in RCC-MR design code. - Abstract: The objective of the present paper is to provide first hand experimental data and analysis on the low cycle fatigue (LCF) performance of a commercial heat of Indian reduced activation ferritic-martensitic (IN-RAFM) steel. Since this material is not yet codified in RCC-MR, cyclic properties were generated for the design of the structural material of the Test Blanket Modules (TBM) made of RAFM steel. Hence, as a part of the material development program, LCF experiments were conducted on IN-RAFM steel obtained in the normalized and tempered condition. Total axial strain controlled experiments were performed in air by employing strain amplitudes ranging from ±0.25 to ±1.0% and at temperatures of 300, 673, 723, 823, and 873 K and a nominal strain rate, 3 × 10{sup −3} s{sup −1}. In the present work, various cyclic parameters that are useful for the design oriented fatigue analysis are derived as per the systematic procedure given in the RCC-MR design code. The physical significance of each design parameter such as elasto-plastic corrections based on Neuber analysis has been explained and correlated with the material behavior such as the cyclic softening nature of the RAFM steel.

Creep-fatigue of High Temperature Materials for VHTR: Effect of Cyclic Loading and Environment

Energy Technology Data Exchange (ETDEWEB)

Celine Cabet; L. Carroll; R. Wright; R. Madland

2011-05-01

Alloy 617 is the one of the leading candidate materials for Intermediate Heat eXchangers (IHX) of a Very High Temperature Reactor (VHTR). System start-ups and shut-downs as well as power transients will produce low cycle fatigue (LCF) loadings of components. Furthermore, the anticipated IHX operating temperature, up to 950°C, is in the range of creep so that creep-fatigue interaction, which can significantly increase the fatigue crack growth, may be one of the primary IHX damage modes. To address the needs for Alloy 617 codification and licensing, a significant creep-fatigue testing program is underway at Idaho National Laboratory. Strain controlled LCF tests including hold times up to 1800s at maximum tensile strain were conducted at total strain range of 0.3% and 0.6% in air at 950°C. Creep-fatigue testing was also performed in a simulated VHTR impure helium coolant for selected experimental conditions. The creep-fatigue tests resulted in failure times up to 1000 hrs. Fatigue resistance was significantly decreased when a hold time was added at peak stress and when the total strain was increased. The fracture mode also changed from transgranular to intergranular with introduction of a tensile hold. Changes in the microstructure were methodically characterized. A combined effect of temperature, cyclic and static loading and environment was evidenced in the targeted operating conditions of the IHX. This paper This paper reviews the data previously published by Carroll and co-workers in references 10 and 11 focusing on the role of inelastic strain accumulation and of oxidation in the initiation and propagation of surface fatigue cracks.

Application of the strain energy for fatigue life prediction (LCF) of metals by the energy-based criterion

International Nuclear Information System (INIS)

Shahram Shahrooi; Ibrahim Henk Metselaar; Zainul Huda; Ghezavati, H.R.

2009-01-01

Full text: In this study, the plastic strain energy under multiaxial fatigue condition has been calculated in the cyclic plasticity models by the stress-strain hysteresis loops. Then, using the results of these models, the fatigue lives in energy-based fatigue model is predicted and compared to experimental data. Moreover, a weighting factor on shear plastic work is presented to decrease the life factors in the model fatigue. (author)

Characterisation and modelling of the microstructural and mechanical evolution of a steam turbine rotor steel

International Nuclear Information System (INIS)

Mayer, T.

2012-01-01

This dissertation deals with the effective mechanical analysis of steam turbine parts which is not only required for the reliable and safe use of newly built steam turbines, but also for the remaining life assessment of components that have been exposed to service duty over long periods of time. This Thesis aims to develop a physically motivated evolutionary constitutive model for a low-alloy bainitic 2CrMoNiWV (23CrMoNiWV8-8) steam turbine rotor steels. A comprehensive experimental characterisation is performed concerning the mechanical and microstructural evolution of 2CrMoNiWV as subjected to low cycle fatigue (LCF) deformation at elevated temperatures, at different strain rates and for various strain amplitudes. This cyclic plastic deformation causes the rearrangement of dislocations in the microstructure of the steels used for such rotor applications. Symmetric, strain controlled LCF experiments have been carried out in the Laboratory of the High Temperature Integrity Group at the Swiss Federal Laboratories for Materials Science and Technology EMPA. These include mechanical tests in the temperature range between 20 °C to 600 °C at strain rates of 0.001%/s to 1.0%/s and strain amplitudes of ±0.25% to ±1.0%. The LCF experiments reported on comprehensively characterise the temperature, strain rate and strain amplitude dependent cyclic elastic-plastic behaviour of 2CrMoNiWV. Both complete single-specimen endurance tests and interrupted multi-specimen tests have been performed. On the basis of this experimental evidence, an evolutionary formulation of the model is further developed that excellently reproduces the strain amplitude dependent mechanical evolution of 2CrMoNiWV when subjected to LCF loading at different constant strain amplitudes but equal temperature and strain rate. The simulation of benchmark experiments introducing increasing or decreasing strain amplitude steps into the LCF deformation history provide promising results. A further important

Characterisation and modelling of the microstructural and mechanical evolution of a steam turbine rotor steel

Energy Technology Data Exchange (ETDEWEB)

Mayer, T.

2012-07-01

This dissertation deals with the effective mechanical analysis of steam turbine parts which is not only required for the reliable and safe use of newly built steam turbines, but also for the remaining life assessment of components that have been exposed to service duty over long periods of time. This Thesis aims to develop a physically motivated evolutionary constitutive model for a low-alloy bainitic 2CrMoNiWV (23CrMoNiWV8-8) steam turbine rotor steels. A comprehensive experimental characterisation is performed concerning the mechanical and microstructural evolution of 2CrMoNiWV as subjected to low cycle fatigue (LCF) deformation at elevated temperatures, at different strain rates and for various strain amplitudes. This cyclic plastic deformation causes the rearrangement of dislocations in the microstructure of the steels used for such rotor applications. Symmetric, strain controlled LCF experiments have been carried out in the Laboratory of the High Temperature Integrity Group at the Swiss Federal Laboratories for Materials Science and Technology EMPA. These include mechanical tests in the temperature range between 20 °C to 600 °C at strain rates of 0.001%/s to 1.0%/s and strain amplitudes of ±0.25% to ±1.0%. The LCF experiments reported on comprehensively characterise the temperature, strain rate and strain amplitude dependent cyclic elastic-plastic behaviour of 2CrMoNiWV. Both complete single-specimen endurance tests and interrupted multi-specimen tests have been performed. On the basis of this experimental evidence, an evolutionary formulation of the model is further developed that excellently reproduces the strain amplitude dependent mechanical evolution of 2CrMoNiWV when subjected to LCF loading at different constant strain amplitudes but equal temperature and strain rate. The simulation of benchmark experiments introducing increasing or decreasing strain amplitude steps into the LCF deformation history provide promising results. A further important

Strain-controlled nonvolatile magnetization switching

Science.gov (United States)

Geprägs, S.; Brandlmaier, A.; Brandt, M. S.; Gross, R.; Goennenwein, S. T. B.

2014-11-01

We investigate different approaches towards a nonvolatile switching of the remanent magnetization in single-crystalline ferromagnets at room temperature via elastic strain using ferromagnetic thin film/piezoelectric actuator hybrids. The piezoelectric actuator induces a voltage-controllable strain along different crystalline directions of the ferromagnetic thin film, resulting in modifications of its magnetization by converse magnetoelastic effects. We quantify the magnetization changes in the hybrids via ferromagnetic resonance spectroscopy and superconducting quantum interference device magnetometry. These measurements demonstrate a significant strain-induced change of the magnetization, limited by an inefficient strain transfer and domain formation in the particular system studied. To overcome these obstacles, we address practicable engineering concepts and use a model to demonstrate that a strain-controlled, nonvolatile magnetization switching should be possible in appropriately engineered ferromagnetic/piezoelectric actuator hybrids.

Influence of PbBi environment on the low-cycle fatigue behavior of SNS target container materials

International Nuclear Information System (INIS)

Kalkhof, D.; Grosse, M.

2003-01-01

The low-cycle fatigue (LCF) behavior of the stainless steel 316L and the 10.5Cr-steel Manet-II was investigated at 260 deg. C in air and in stagnant lead-bismuth (PbBi). At low-strain levels, the fatigue lives for 316L in PbBi and air were comparable. At total strain amplitudes of 0.50% and higher a weak influence of PbBi was observed. In contrast to 316L, the results of LCF tests for Manet-II in PbBi showed a significant reduction of lifetime for all applied strain amplitudes. In the worst case the cycle number to crack initiation was reduced by a factor of ∼7 compared with the comparable test in air. For the low-strain amplitude of 0.30%, fatigue tests conducted at a frequency of 0.1 Hz had shorter fatigue lives than at a frequency of 1.0 Hz. For Manet-II the crack propagation in PbBi was much faster than in air, and failure immediate followed the formation of the first macroscopic crack

Failure Mechanisms and Damage Model of Ductile Cast Iron Under Low-Cycle Fatigue Conditions

Science.gov (United States)

Wu, Xijia; Quan, Guangchun; MacNeil, Ryan; Zhang, Zhong; Sloss, Clayton

2014-10-01

Strain-controlled low-cycle fatigue (LCF) tests were conducted on ductile cast iron (DCI) at strain rates of 0.02, 0.002, and 0.0002/s in the temperature range from room temperature to 1073 K (800 °C). A constitutive-damage model was developed within the integrated creep-fatigue theory (ICFT) framework on the premise of strain decomposition into rate-independent plasticity and time-dependent creep. Four major damage mechanisms: (i) plasticity-induced fatigue, (ii) intergranular embrittlement (IE), (iii) creep, and (iv) oxidation were considered in a nonlinear creep-fatigue interaction model which represents the overall damage accumulation process consisting of oxidation-assisted fatigue crack nucleation and propagation in coalescence with internally distributed damage ( e.g., IE and creep), leading to final fracture. The model was found to agree with the experimental observations of the complex DCI-LCF phenomena, for which the linear damage summation rule would fail.

Secondary Hardening Behavior in Super Duplex Stainless Steels during LCF in Dynamic Strain Ageing Regime

OpenAIRE

Chai, Guocai; Andersson, Marcus

2013-01-01

Cyclic deformation behaviors in five modified duplex stainless steel S32705 grades have been studied at 20 °C, 200 °C, 250° and 350 °C. The influence of temperature and nitrogen concentration on the occurrence of the second hardening phenomenon, in the stress response curve was focused. An increase in nitrogen concentration can have a positive effect on dynamic strain ageing by increasing the first hardening and also the second hardening behavior during cyclic deformation. Furthermore, an inc...

Standard practice for strain controlled thermomechanical fatigue testing

CERN Document Server

American Society for Testing and Materials. Philadelphia

2010-01-01

1.1 This practice covers the determination of thermomechanical fatigue (TMF) properties of materials under uniaxially loaded strain-controlled conditions. A “thermomechanical” fatigue cycle is here defined as a condition where uniform temperature and strain fields over the specimen gage section are simultaneously varied and independently controlled. This practice is intended to address TMF testing performed in support of such activities as materials research and development, mechanical design, process and quality control, product performance, and failure analysis. While this practice is specific to strain-controlled testing, many sections will provide useful information for force-controlled or stress-controlled TMF testing. 1.2 This practice allows for any maximum and minimum values of temperature and mechanical strain, and temperature-mechanical strain phasing, with the restriction being that such parameters remain cyclically constant throughout the duration of the test. No restrictions are placed on en...

Controlling nitrogen migration through micro-nano networks.

Science.gov (United States)

Cai, Dongqing; Wu, Zhengyan; Jiang, Jiang; Wu, Yuejin; Feng, Huiyun; Brown, Ian G; Chu, Paul K; Yu, Zengliang

2014-01-14

Nitrogen fertilizer unabsorbed by crops eventually discharges into the environment through runoff, leaching and volatilization, resulting in three-dimensional (3D) pollution spanning from underground into space. Here we describe an approach for controlling nitrogen loss, developed using loss control fertilizer (LCF) prepared by adding modified natural nanoclay (attapulgite) to traditional fertilizer. In the aqueous phase, LCF self-assembles to form 3D micro/nano networks via hydrogen bonds and other weak interactions, obtaining a higher nitrogen spatial scale so that it is retained by a soil filtering layer. Thus nitrogen loss is reduced and sufficient nutrition for crops is supplied, while the pollution risk of the fertilizer is substantially lowered. As such, self-fabrication of nano-material was used to manipulate the nitrogen spatial scale, which provides a novel and promising approach for the research and control of the migration of other micro-scaled pollutants in environmental medium.

Effects of Control Mode and R-Ratio on the Fatigue Behavior of a Metal Matrix Composite

Science.gov (United States)

2005-01-01

Composite Because of their high specific stiffness and strength at elevated temperatures, continuously reinforced metal matrix composites (MMC's) are under consideration for a future generation of aeropropulsion systems. Since components in aeropropulsion systems experience substantial cyclic thermal and mechanical loads, the fatigue behavior of MMC's is of great interest. Almost without exception, previous investigations of the fatigue behavior of MMC's have been conducted in a tension-tension, load-controlled mode. This has been due to the fact that available material is typically less than 2.5-mm thick and, therefore, unable to withstand high compressive loads without buckling. Since one possible use of MMC's is in aircraft skins, this type of testing mode may be appropriate. However, unlike aircraft skins, most engine components are thick. In addition, the transient thermal gradients experienced in an aircraft engine will impose tension-compression loading on engine components, requiring designers to understand how the MMC will behave under fully reversed loading conditions. The increased thickness of the MMC may also affect the fatigue life. Traditionally, low-cycle fatigue (LCF) tests on MMC's have been performed in load control. For monolithic alloys, low-cycle fatigue tests are more typically performed in strain control. Two reasons justify this choice: (1) the critical volume from which cracks initiate and grow is generally small and elastically constrained by the larger surrounding volume of material, and (2) load-controlled, low-cycle fatigue tests of monolithics invariably lead to unconstrained ratcheting and localized necking--an undesired material response because the failure mechanism is far more severe than, and unrelated to, the fatigue mechanism being studied. It is unknown if this is the proper approach to composite testing. However, there is a lack of strain-controlled data on which to base any decisions. Consequently, this study addresses the

Total Strain FE Model for Reinforced Concrete Floors on Piles

NARCIS (Netherlands)

Hofmeyer, H.; Bos, van den A.A.

2008-01-01

A finite element (FE) model using a total strain material model has been developed to predict the behavior of warehouse reinforced concrete floors on piles. The material model (not the FE model itself) was calibrated to material tests. The FE model for the floor structure was checked with full-scale

LCF behavior of Zr-4 alloy at elevated temperature

International Nuclear Information System (INIS)

Ye Yuming; Cai Lixun

2006-01-01

A series of strain fatigue tests were carried out on small bugle-like slice-specimens of Zr-4 alloy at room temperature and 400 degree C. According to Elastic and Plastic Finite Element Analysis and assumption of local damage equivalence, a strain conversion equation was given to transform the transverse strain of the specimen to the axial strain. Based on the test results of the alloy and the strain conversion equation, fatigue life estimation equations of Zr-4alloy, or M-C (Manson-Coffin) models, were obtained. The results showed that, Zr-4 alloy had obvious cyclic hardening character during high amplitude strain at different temperatures, but showed reverse character during low amplitude strain. Elevated temperature lowered seriously the fatigue life of Zr-4 alloys, ann as the increasing of amplitude strain, temperature effect impaired gradually. Analysis showed that the prediction life by using M-C model based on the traditional strain conversion equation was quite conservative when axial strain amplitude was less than 5000 micro-strain. (authors)

Life time calculations for LCF loading combined with tensional hold periods

International Nuclear Information System (INIS)

Bocek, M.; Armas, A.; Piel, D.

1983-01-01

The life time in high amplitude strain cycling with tensional hold periods is analysed presuming that creep failure damage is life determining. The life fraction rule (LFR) is used to calculate the life time consumpted during the dwell period in strain controlled tests as well as during tensional hold time stress cycles. It follows from the present investigation that stress relaxation occurring during the strain hold periods plays the dominant influence upon the relationship between life and dwell time. For strong stress relaxation (e.g. high temperature) less damage is accumulated as compared to suppressed relaxation (low temperature). The damage in stress relaxation is calculated by means of the LFR and the results are compared to experiments conducted on Zircaloy-4 and the austenitic stainless stell Type AISI 304. From the very good agreement between both it is concluded that under the loading conditions considered, creep failure damage is the main life determining damage contribution. (orig.)

Modeling of uniaxial ratchetting behavior of SA333 carbon manganese steel

International Nuclear Information System (INIS)

Shit, J.; Dhar, S.; Acharyya, S.K.; Goyal, S.

2012-01-01

The paper deals with uniaxial ratcheting phenomenon of cyclic plasticity behavior of the materials SA333 carbon Manganese steel. A mechanistic model for the ratcheting phenomenon has been proposed. It is observed that von Mises yield criterion together with Chaboche’s kinematic hardening rules are not sufficient to model ratcheting phenomenon. Other associated phenomena like plastic strain memory surface, back stress memory points and over all the extra hardening behavior have to be incorporated to get a complete material model for ratcheting. The proposed model assembled all these ideas together with von Mises yield criterion and Chabache’s kinematic hardening rule. Low cycle fatigue tests and uniaxial ratcheting tests have been conducted for the materials. The material constants are identified and derived from experimental results. The ratcheting coefficients have been properly calibrated with these material constants. The material model, as mentioned above, for the ratcheting phenomenon has been implemented in an elastic plastic finite element code. The ratcheting results for different stress controlled ratcheting loads have been computed. The good feature of this model is that it reduces to symmetric low cycle fatigue model when loop closes. - Highlights: ► A common material model to simulate symmetric LCF and ratcheting. ► Extra hardening to take care the shift of plastic strain centre. ► Material parameters from tensile and LCF tests. ► Saturated loop in LCF and ratcheting strain rate is compared with experiment. ► Consideration of loading path, memory path and their directions.

Low and high cycle fatigue behaviour of steel-X6CRNI1811 (Type 304 SS) in air and flowing sodium

International Nuclear Information System (INIS)

Huthmann, H.; Jenner, G.

Strain controlled LCF-tests were performed on X6CrNi1811 steel (Type 304 SS) in air and flowing sodium in a non-isothermal sodium loop. The results measured at 550 deg. C in an upstream position of the sodium loop show an increase in fatigue life in the strain range from about 1.5% to 0.4% for the base material in the as-received condition while the welded joints remain unaffected by the environment. The LCF-behaviour of base material specimens tested at 500 deg. C in a downstream position after a prior pre-exposure to sodium (4058 h, 500 deg. C) is also improved in comparison to parallel specimens tested in air with comparable thermal aging. Load controlled HCF-tests performed on X6CrNi1811 steel at 550 deg. C show a significant increase in fatigue life in the low cycle region (Nsub(f) 6 cycles) and a higher endurance limit for the base material in sodium but no influence of the environment is indicated for the welded joints. (author)

Low cycle fatigue characteristics of duplex stainless steel with degradation under pure torsional load

International Nuclear Information System (INIS)

Kwon, Jae Do; Park, Joong Cheul

2002-01-01

Monotonic torsional and pure torsional low cycle fatigue (LCF) test with artificial degradation were performed on duplex stainless steel (CF8M). CF8M is used in pipes and valves in nuclear reactor coolant system. It was aged at 430 degree C for 3600hrs. Through the monotonic and LCF test, it is found that mechanical properties (i.e., yield strength, strain hardening exponent, strength coefficient etc.) increase and fatigue life (N f ) decreases with degradation of material. The relationship between shear strain amplitude (γ α ) and N f was proposed

Influence of microstructure on low cycle fatigue in some single phase and biphasic stainless steels

Energy Technology Data Exchange (ETDEWEB)

Stolarz, J. [Ecole Nationale Superieure des Mines, Centre SMS, URA CNRS 1884, Saint-Etienne (France)

2004-07-01

This overview deals with the effects of microstructural parameters in different single phase and biphasic stainless steels on short crack behaviour and on fatigue life in the low cycle regime. The effect of the grain size is investigated in a single phase austenitic stainless steel. Under plastic strain control, the fatigue life increases when the grain size decreases. The results are discussed by analysing the distributions of crack depths as a function of the grain size. The second type of material is a metastable austenitic steel which partially transforms into martensite during LCF at temperatures between -50 C and +120 C. The grain size of the initially single phase austenitic microstructure has a combined influence on the volume fraction of martensite produced during fatigue and on the fatigue life. In this case, the grain size effect is still considerable but totally indirect because all fatigue cracks grow exclusively in the martensite. The cyclic behaviour analysis in biphasic alloys in which two phases undergo plastic deformation during LCF is considerably more complex because the conventional concept of microstructural barriers cannot be applied. The possible damage patterns in a pair of grains with different mechanical properties are discussed on the example of a solution treated and aged superduplex austenitic-ferritic stainless steel (SDSS). The hardening of one phase (ferrite) through ageing at 475 C changes the cyclic behaviour of the initial ''quasi single phase'' microstructure. Consequently, the fatigue life under plastic strain control decreases compared with the solution treated SDSS. The discussion is focussed on LCF damage mechanisms at the microstructure size scale with a particular accent put on the propagation of short cracks in the bulk. All the microstructures exhibit some common features with respect to the behaviour of short cracks. In particular a strong effect of microstructural barriers in the bulk and the

Differences in the cyclic deformation behaviour of quenched and tempered steel 42 CrMo 4 (AISI 4140) due to stress- and strain-control

International Nuclear Information System (INIS)

Schulze, V.; Lang, K.-H.; Voehringer, O.; Macherauch, E.

1998-01-01

Cyclic stress-strain-curves and Manson-Coffin-plots of quenched and tempered steel 42 CrMo 4 (AISI 4140) strongly depend on whether they are determined under stress- or total-strain-control. At total-strain-controlled experiments, this is caused on the one hand by comparatively high initial stress-amplitudes which lead to distinctive cyclic work softening. On the other hand, the occuring differences in the evolution of inhomogeneous deformation patterns at both types of loading, which can be recorded by means of photoelasticity and microscopy, lead to differently distributed plastic deformations and to different integral values of plastic strain. (orig.)

Effect of alloying composition on low-cycle fatigue properties and microstructure of Fe–30Mn–(6−x)Si–xAl TRIP/TWIP alloys

Energy Technology Data Exchange (ETDEWEB)

Nikulin, Ilya, E-mail: nikulin.i.a@gmail.com [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Belgorod State University, Pobeda 85, Belgorod 308015 (Russian Federation); Sawaguchi, Takahiro [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Tsuzaki, Kaneaki [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

2013-12-10

The change in low-cycle fatigue (LCF) properties and deformation microstructure due to the alteration of aluminum and silicon contents was studied in relation with the tensile properties in Fe–30Mn–(6−x)Si–xAl (x=0, 1, 2, 3, 4, 5, 6 wt%) alloys, which are high-Mn austenitic TRIP/TWIP alloys. Austenite to ε-martensite transformation took place during LCF deformation in the TRIP alloys with x≤2 while mechanical twinning was not observed by electron-backscattering diffraction (EBSD) analysis in the TWIP alloys with x>2 after LCF deformation. The fatigue resistance of the alloys was shown to be correlated with the tensile proof strength and the hardening rate. Superior fatigue life of 8×10{sup 3} cycles at a total strain range Δε=2% was found in the Fe–30Mn–4Si–2Al TRIP alloy with a low fraction of ε-martensite, high tensile proof strength and low hardening rate at both tensile and fatigue deformations. On the other hand, a considerable decrease in the fatigue properties was observed in the alloys with decreasing proof strength and increasing hardening rate. Proof strength provided by the solid solution of Al and Si, represents the hampering of plastic deformation, and the hardening rate reflects the strain reversibility affected by the stacking fault energy (SFE) through the rate of austenite to martensite transformation in the TRIP alloys and the substructure formation in the TWIP alloys.

Strain actuated aeroelastic control

Science.gov (United States)

Lazarus, Kenneth B.

1992-01-01

Viewgraphs on strain actuated aeroelastic control are presented. Topics covered include: structural and aerodynamic modeling; control law design methodology; system block diagram; adaptive wing test article; bench-top experiments; bench-top disturbance rejection: open and closed loop response; bench-top disturbance rejection: state cost versus control cost; wind tunnel experiments; wind tunnel gust alleviation: open and closed loop response at 60 mph; wind tunnel gust alleviation: state cost versus control cost at 60 mph; wind tunnel command following: open and closed loop error at 60 mph; wind tunnel flutter suppression: open loop flutter speed; and wind tunnel flutter suppression: closed loop state cost curves.

An investigation on high temperature fatigue properties of tempered nuclear-grade deposited weld metals

Science.gov (United States)

Cao, X. Y.; Zhu, P.; Yong, Q.; Liu, T. G.; Lu, Y. H.; Zhao, J. C.; Jiang, Y.; Shoji, T.

2018-02-01

Effect of tempering on low cycle fatigue (LCF) behaviors of nuclear-grade deposited weld metal was investigated, and The LCF tests were performed at 350 °C with strain amplitudes ranging from 0.2% to 0.6%. The results showed that at a low strain amplitude, deposited weld metal tempered for 1 h had a high fatigue resistance due to high yield strength, while at a high strain amplitude, the one tempered for 24 h had a superior fatigue resistance due to high ductility. Deposited weld metal tempered for 1 h exhibited cyclic hardening at the tested strain amplitudes. Deposited weld metal tempered for 24 h exhibited cyclic hardening at a low strain amplitude but cyclic softening at a high strain amplitude. Existence and decomposition of martensite-austenite (M-A) islands as well as dislocations activities contributed to fatigue property discrepancy among the two tempered deposited weld metal.

Influence of Localized Plasticity on IASCC Sensitivity of Austenitic Stainless Steels under PWR Primary Water

Science.gov (United States)

Cissé, Sarata; Tanguy, Benoit; Laffont, Lydia; Lafont, Marie-Christine; Guerre, Catherine; Andrieu, Eric

The sensibility of precipitation-strengthened A286 austenitic stainless steel to Stress Corrosion Cracking (SCC) is studied by means of Slow Strain Rate Tests (SSRT). First, alloy cold working by Low Cycle Fatigue (LCF) is investigated. Fatigue tests under plastic strain control are performed at different strain levels (Δ ɛp/2=0.2%, 0.5% and 0.8%) in order to establish correlation between stress softening and deformation microstructure resulting from LCF tests. Deformed microstructures have been identified through TEM investigations. Three states of cyclic behaviour for precipitation-strengthened A286 have been identified: hardening, cyclic softening and finally saturation of softening. It is shown that the A286 alloy cyclic softening is due to microstructural features such as defects — free deformation bands resulting from dislocations motion along family plans , that swept defects or γ' precipitates and lead to deformation localization. In order to quantify effects of plastic localized deformation on intergranular stress corrosion cracking (IGSCC) of the A286 alloy in PWR primary water, slow strain rate tests are conducted. For each cycling conditions, two specimens at a similar stress level are tested: the first containing free precipitate deformation bands, the other not significant of a localized deformation state. SSRT tests are still in progress.

Crack initiation and propagation in welded joints of turbine and boiler steels during low cycle fatigue

International Nuclear Information System (INIS)

Lindblom, J.; Sandstroem, R.; Linde, L.; Henderson, P.

1990-01-01

Low cycle fatigue (LCF) tests have been performed at 300 and 565 degrees C on welded joints and on microstructures to be found in or near welded joints in a low alloy ferritic steel 0.5 Cr, 0.5 Mo, 0.25 V. The difference in lifetimes between the 300 degrees C and 565 degrees C tests was small comparing the same microstructures and strain ranges, although the stress amplitude was greater at 300 degrees C. Under constant stress conditions the fatigue life depended on the fatigue life of the parent metal but under constant strain conditions the lifetime was governed by that of the bainitic structures. Strain controlled LCF tests have been performed at 750 degrees C on welded joints in the austenitic steel AISI 316 and on different parent and weld metals used in these joints. In continuously cycled samples all cracks were transgranular and initiated at the surface; hold-time samples displayed internally initiated intergranular cracking in the weld metal. Under constant strain conditions the 316 parent and weld metals exhibited similar lifetimes. When considering a constant stress situation the strength of the microsturctures decreased in the following order: Sanicro weld metal, cold deformed parent metal, undeformed parent metal and weld metal (K.A.E.)

Low cycle fatigue behavior of ITER-like divertor target under DEMO-relevant operation conditions

Energy Technology Data Exchange (ETDEWEB)

Li, Muyuan; Werner, Ewald [Lehrstuhl für Werkstoffkunde und Werkstoffmechanik, Technische Universität München, Boltzmannstr. 15, 85748 Garching (Germany); You, Jeong-Ha, E-mail: you@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany)

2015-01-15

Highlights: • LCF behavior of the cooling tube and the interlayer of an ITER-like divertor target is studied. • For the cooling tube, LCF failure will not be an issue under an HHF load of up to 18 MW/m{sup 2}. • Plastic strain in the interlayer is concentrated at the free surface edge of the bond interface. • The predicted LCF lifetime of the interlayer may not meet the design requirement. - Abstract: In this work the low cycle fatigue (LCF) behavior of the copper alloy cooling tube and the copper interlayer of an ITER-like divertor target is reported for nine different combinations of loading and cooling conditions relevant to DEMO divertor operation. The LCF lifetime is presented as a function of loading and cooling conditions considered here by means of cyclic plasticity simulation and using LCF data of materials relevant for ITER. The numerical predictions indicate, that fatigue failure will not be an issue for the copper alloy tube under a high heat flux (HHF) load of up to 18 MW/m{sup 2} as long as it preserves its initial strength. In contrast, the copper interlayer exhibits significant plastic dissipation at the free surface edge of the bond interface adjacent to the cooling tube, where the LCF lifetime is predicted to be below 3000 load cycles for HHF loads higher than 15 MW/m{sup 2}. Most of the bulk region of the copper interlayer away from the free surface edge does not experience severe plastic fatigue and hence does not pose any critical concern as the LCF lifetime is predicted to be at least 7000 load cycles. LCF lifetime decreases as HHF load is increased or coolant temperature is decreased.

Strain-controlled electrocatalysis on multimetallic nanomaterials

Science.gov (United States)

Luo, Mingchuan; Guo, Shaojun

2017-11-01

Electrocatalysis is crucial for the development of clean and renewable energy technologies, which may reduce our reliance on fossil fuels. Multimetallic nanomaterials serve as state-of-the-art electrocatalysts as a consequence of their unique physico-chemical properties. One method of enhancing the electrocatalytic performance of multimetallic nanomaterials is to tune or control the surface strain of the nanomaterials, and tremendous progress has been made in this area in the past decade. In this Review, we summarize advances in the introduction, tuning and quantification of strain in multimetallic nanocrystals to achieve more efficient energy conversion by electrocatalysis. First, we introduce the concept of strain and its correlation with other key physico-chemical properties. Then, using the electrocatalytic reduction of oxygen as a model reaction, we discuss the underlying mechanisms behind the strain-adsorption-reactivity relationship based on combined classical theories and models. We describe how this knowledge can be harnessed to design multimetallic nanocrystals with optimized strain to increase the efficiency of oxygen reduction. In particular, we highlight the unexpectedly beneficial (and previously overlooked) role of tensile strain from multimetallic nanocrystals in improving electrocatalysis. We conclude by outlining the challenges and offering our perspectives on the research directions in this burgeoning field.

Repeated Strains, Social Control, Social Learning, and Delinquency: Testing an Integrated Model of General Strain Theory in China

Science.gov (United States)

Bao, Wan-Ning; Haas, Ain; Chen, Xiaojin; Pi, Yijun

2014-01-01

In Agnew's general strain theory, repeated strains can generate crime and delinquency by reducing social control and fostering social learning of crime. Using a sample of 615 middle-and high-school students in China, this study examines how social control and social learning variables mediate the effect of repeated strains in school and at home on…

Rat Strain Ontology: structured controlled vocabulary designed to facilitate access to strain data at RGD.

Science.gov (United States)

Nigam, Rajni; Munzenmaier, Diane H; Worthey, Elizabeth A; Dwinell, Melinda R; Shimoyama, Mary; Jacob, Howard J

2013-11-22

The Rat Genome Database (RGD) ( http://rgd.mcw.edu/) is the premier site for comprehensive data on the different strains of the laboratory rat (Rattus norvegicus). The strain data are collected from various publications, direct submissions from individual researchers, and rat providers worldwide. Rat strain, substrain designation and nomenclature follow the Guidelines for Nomenclature of Mouse and Rat Strains, instituted by the International Committee on Standardized Genetic Nomenclature for Mice. While symbols and names aid in identifying strains correctly, the flat nature of this information prohibits easy search and retrieval, as well as other data mining functions. In order to improve these functionalities, particularly in ontology-based tools, the Rat Strain Ontology (RS) was developed. The Rat Strain Ontology (RS) reflects the breeding history, parental background, and genetic manipulation of rat strains. This controlled vocabulary organizes strains by type: inbred, outbred, chromosome altered, congenic, mutant and so on. In addition, under the chromosome altered category, strains are organized by chromosome, and further by type of manipulations, such as mutant or congenic. This allows users to easily retrieve strains of interest with modifications in specific genomic regions. The ontology was developed using the Open Biological and Biomedical Ontology (OBO) file format, and is organized on the Directed Acyclic Graph (DAG) structure. Rat Strain Ontology IDs are included as part of the strain report (RS: ######). As rat researchers are often unaware of the number of substrains or altered strains within a breeding line, this vocabulary now provides an easy way to retrieve all substrains and accompanying information. Its usefulness is particularly evident in tools such as the PhenoMiner at RGD, where users can now easily retrieve phenotype measurement data for related strains, strains with similar backgrounds or those with similar introgressed regions. This

Forecasting Low-Cycle Fatigue Performance of Twinning-Induced Plasticity Steels: Difficulty and Attempt

Science.gov (United States)

Shao, C. W.; Zhang, P.; Zhang, Z. J.; Liu, R.; Zhang, Z. F.

2017-12-01

We find the existing empirical relations based on monotonic tensile properties and/or hardness cannot satisfactorily predict the low-cycle fatigue (LCF) performance of materials, especially for twinning-induced plasticity (TWIP) steels. Given this, we first identified the different deformation mechanisms under monotonic and cyclic deformation after a comprehensive study of stress-strain behaviors and microstructure evolutions for Fe-Mn-C alloys during tension and LCF, respectively. It is found that the good tensile properties of TWIP steel mainly originate from the large activation of multiple twinning systems, which may be attributed to the grain rotation during tensile deformation; while its LCF performance depends more on the dislocation slip mode, in addition to its strength and plasticity. Based on this, we further investigate the essential relations between microscopic damage mechanism (dislocation-dislocation interaction) and cyclic stress response, and propose a hysteresis loop model based on dislocation annihilation theory, trying to quickly assess the LCF resistance of Fe-Mn-C steels as well as other engineering materials. It is suggested that the hysteresis loop and its evolution can provide significant information on cyclic deformation behavior, e.g., (point) defect multiplication and vacancy aggregation, which may help estimate the LCF properties.

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

International Nuclear Information System (INIS)

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

2016-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-06-15

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

Shape recovery and irrecoverable strain control in polyurethane shape-memory polymer

International Nuclear Information System (INIS)

Tobushi, Hisaaki; Ejiri, Yoshihiro; Hayashi, Syunichi; Hoshio, Kazumasa

2008-01-01

In shape-memory polymers, large strain can be fixed at a low temperature and thereafter recovered at a high temperature. If the shape-memory polymer is held at a high temperature for a long time, the irrecoverable strain can attain a new intermediate shape between the shape under the maximum stress and the primary shape. Irrecoverable strain control can be applied to the fabrication of a shape-memory polymer element with a complex shape in a simple method. In the present study, the influence of the strain-holding conditions on the shape recovery and the irrecoverable strain control in polyurethane shape-memory polymer is investigated by tension test of a film and three-point bending test of a sheet. The higher the shape-holding temperature and the longer the shape-holding time, the higher the irrecoverable strain rate. The equation that expresses the characteristics of the irrecoverable strain control is formulated

A procedure to generate input data of cyclic softening and hardening for FEM analysis from constant strain amplitude fatigue tests in LCF regime

International Nuclear Information System (INIS)

Sarajaervi, U.; Cronvall, O.

2007-03-01

Fatigue is produced by cyclic application of stresses by mechanical or thermal loading. The metal subjected to fluctuating stress will fail at stresses much lower than those required to cause fracture in a single application of load. The key parameters are the range of stress variation and the number of its occurrences. Low-cycle fatigue, usually induced by mechanical and thermal loads, is distinguished from high-cycle fatigue, mainly associated with vibration or high number of small thermal fluctuations. Numerical models describing fatigue behaviour of austenitic stainless piping steels under cyclic loading and their applicability for modelling of low-cycle-fatigue are discussed in this report. In order to describe the cyclic behaviour of the material for analysis with finite element method (FEM) based analysis code ABAQUS, the test data, i.e. stress-strain curves, have to be processed. A code to process the data all through the test duration was developed within this study. A description of this code is given also in this report. Input data for ABAQUS was obtained to describe both kinematic and isotropic hardening properties. Further, by combining the result data for various strain amplitudes a mathematic expression was be created which allows defining a parameter surface for cyclic (i.e. isotropic) hardening. Input data for any strain amplitude within the range of minimum and maximum strain amplitudes of the test data can be assessed with the help of the developed 3D stress-strain surface presentation. The modelling of the fatigue induced initiation and growth of cracks was not considered in this study. On the other hand, a considerable part of the fatigue life of nuclear power plant (NPP) piping components is spent in the phase preceding the initiation and growth of cracks. (au)

A procedure to generate input data of cyclic softening and hardening for FEM analysis from constant strain amplitude fatigue tests in LCF regime

Energy Technology Data Exchange (ETDEWEB)

Sarajaervi, U.; Cronvall, O. [VTT (Finland)

2007-03-15

Fatigue is produced by cyclic application of stresses by mechanical or thermal loading. The metal subjected to fluctuating stress will fail at stresses much lower than those required to cause fracture in a single application of load. The key parameters are the range of stress variation and the number of its occurrences. Low-cycle fatigue, usually induced by mechanical and thermal loads, is distinguished from high-cycle fatigue, mainly associated with vibration or high number of small thermal fluctuations. Numerical models describing fatigue behaviour of austenitic stainless piping steels under cyclic loading and their applicability for modelling of low-cycle-fatigue are discussed in this report. In order to describe the cyclic behaviour of the material for analysis with finite element method (FEM) based analysis code ABAQUS, the test data, i.e. stress-strain curves, have to be processed. A code to process the data all through the test duration was developed within this study. A description of this code is given also in this report. Input data for ABAQUS was obtained to describe both kinematic and isotropic hardening properties. Further, by combining the result data for various strain amplitudes a mathematic expression was be created which allows defining a parameter surface for cyclic (i.e. isotropic) hardening. Input data for any strain amplitude within the range of minimum and maximum strain amplitudes of the test data can be assessed with the help of the developed 3D stress-strain surface presentation. The modelling of the fatigue induced initiation and growth of cracks was not considered in this study. On the other hand, a considerable part of the fatigue life of nuclear power plant (NPP) piping components is spent in the phase preceding the initiation and growth of cracks. (au)

Low cycle fatigue properties of neutron irradiated solid HIP 316L(N). ITER Task T214, NET deliverable GB6 ECN-5

International Nuclear Information System (INIS)

Rensman, J.; Van Osch, E.V.; Tjoa, G.L.; Boskeljon, J.; Van Hoepen, J.

1998-05-01

The Low Cycle Fatigue (LCF) properties of neutron irradiated Hot Isostatically Pressed (HIP) joints of type 316L(N) stainless steel (heat PM-130) have been measured, as well as the LCF properties of reference 316L(N)-ERHII. Cylindrical LCF test specimens of 3 mm diameter were irradiated in the High Flux Reactor (HFR) in Petten, The Netherlands, simulating the first wall conditions of future fusion reactors by a combination of high displacement damage with proportional amounts of helium. The solid HIP specimens were irradiated up to a target dose level of 5 dpa at a temperature of 550K. The damage levels realised range from 3.0 to 4.4 dpa, with helium contents up to 41 appm. Testing temperature was equal to the irradiation temperature: 550K. The report contains the experimental conditions and summarises the results, which are given in terms of first cycle stress, the peak stress, the number of cycles where the peak stress is reached, the stress at half life and the plastic strain at half life, and the total number of cycles to failure, N f . The main conclusions are that the unirradiated solid-HIP materials has the same LCF properties as unirradiated 316L(N)-ERHII plate material. The neutron irradiation induces both hardening and reduction of fatigue life. The bond does not seem to have any effect on the fatigue properties for the unirradiated solid HIP 316L(N), whereas a combined effect of irradiation and the bond cannot be established. No failures related to debonding of the joint were observed for the tests. 7 refs

Association between job strain (high demand-low control and cardiovascular disease risk factors among petrochemical industry workers

Directory of Open Access Journals (Sweden)

Siamak Poorabdian

2013-08-01

Full Text Available Objective: One of the practical models for assessment of stressful working conditions due to job strain is "job demand and control" or Karasek's job strain model. This model explains how adverse physical and psychological effects including cardiovascular disease risk factors can be established due to high work demand. The aim was to investigate how certain cardiovascular risk factors including body mass index (BMI, heart rate, blood pressure, serum total cholesterol levels, and cigarette smoking are associated with job demand and control in workers. Materials and Methods: In this cohort study, 500 subjects completed "job demand and control" questionnaires. Factor analysis method was used in order to specify the most important "job demand and control" questions. Health check-up records of the workers were applied to extract data about cardiovascular disease risk factors. Ultimately, hypothesis testing, based on Eta, was used to assess the relationship between separated working groups and cardiovascular risk factors (hypertension and serum total cholesterol level. Results: A significant relationship was found between the job demand-control model and cardiovascular risk factors. In terms of chisquared test results, the highest value was assessed for heart rate (Chi2 = 145.078. The corresponding results for smoking and BMI were Chi2 = 85.652 and Chi2 = 30.941, respectively. Subsequently, Eta result for total cholesterol was 0.469, followed by hypertension equaling 0.684. Moreover, there was a significant difference between cardiovascular risk factors and job demand-control profiles among different working groups including the operational group, repairing group and servicing group. Conclusion: Job control and demand are significantly related to heart disease risk factors including hypertension, hyperlipidemia, and cigarette smoking.

Controllable spin-charge transport in strained graphene nanoribbon devices

Energy Technology Data Exchange (ETDEWEB)

Diniz, Ginetom S., E-mail: ginetom@gmail.com; Guassi, Marcos R. [Institute of Physics, University of Brasília, 70919-970, Brasília-DF (Brazil); Qu, Fanyao [Institute of Physics, University of Brasília, 70919-970, Brasília-DF (Brazil); Department of Physics, The University of Texas at Austin, Austin, Texas 78712 (United States)

2014-09-21

We theoretically investigate the spin-charge transport in two-terminal device of graphene nanoribbons in the presence of a uniform uniaxial strain, spin-orbit coupling, exchange field, and smooth staggered potential. We show that the direction of applied strain can efficiently tune strain-strength induced oscillation of band-gap of armchair graphene nanoribbon (AGNR). It is also found that electronic conductance in both AGNR and zigzag graphene nanoribbon (ZGNR) oscillates with Rashba spin-orbit coupling akin to the Datta-Das field effect transistor. Two distinct strain response regimes of electronic conductance as function of spin-orbit couplings magnitude are found. In the regime of small strain, conductance of ZGNR presents stronger strain dependence along the longitudinal direction of strain. Whereas for high values of strain shows larger effect for the transversal direction. Furthermore, the local density of states shows that depending on the smoothness of the staggered potential, the edge states of AGNR can either emerge or be suppressed. These emerging states can be determined experimentally by either spatially scanning tunneling microscope or by scanning tunneling spectroscopy. Our findings open up new paradigms of manipulation and control of strained graphene based nanostructure for application on novel topological quantum devices.

Short fatigue cracks nucleation and growth in lean duplex stainless steel LDX 2101

Energy Technology Data Exchange (ETDEWEB)

Strubbia, R., E-mail: strubbia@ifir-conicet.gov.ar [Instituto de Física Rosario – CONICET, Universidad Nacional de Rosario (Argentina); Hereñú, S.; Alvarez-Armas, I. [Instituto de Física Rosario – CONICET, Universidad Nacional de Rosario (Argentina); Krupp, U. [Faculty of Engineering and Computer Science, University of Applied Sciences Osnabrück (Germany)

2014-10-06

This work is focused on the fatigue damage of lean duplex stainless steels (LDSSs) LDX 2101. Special interest is placed on analyzing short fatigue crack behavior. In this sense, short crack initiation and growth during low cycle fatigue (LCF) and short crack nucleation during high cycle fatigue (HCF) of this LDSS have been studied. The active slip systems and their associated Schmid factors (SF) are determined using electron backscattered diffraction (EBSD). Additionally, the dislocation structure developed during cycling is observed by transmission electron microscopy (TEM). Regardless of the fatigue regime, LCF and HCF, short cracks nucleate along intrusion/extrusions in ferritic grains. Moreover, during the LCF phase boundaries decelerate short crack propagation. These results are rationalized by the hardness of the constitutive phases and the dependence of screw dislocation mobility in the ferrite phase on strain rate and stress amplitude.

A Constitutive Model for Strain-Controlled Strength Degradation of Rockmasses (SDR)

Science.gov (United States)

Kalos, A.; Kavvadas, M.

2017-11-01

The paper describes a continuum, rate-independent, incremental plasticity constitutive model applicable in weak rocks and heavily fractured rockmasses, where mechanical behaviour is controlled by rockmass strength rather than structural features (discontinuities). The model describes rockmass structure by a generalised Hoek-Brown Structure Envelope (SE) in the stress space. Stress paths inside the SE are nonlinear and irreversible to better simulate behaviour at strains up to peak strength and under stress reversals. Stress paths on the SE have user-controlled volume dilatancy (gradually reducing to zero at large shear strains) and can model post-peak strain softening of brittle rockmasses via a structure degradation (damage) mechanism triggered by accumulated plastic shear strains. As the SE may strain harden with plastic strains, ductile behaviour can also be modelled. The model was implemented in the Finite Element Code Simulia ABAQUS and was applied in plane strain (2D) excavation of a cylindrical cavity (tunnel) to predict convergence-confinement curves. It is shown that small-strain nonlinearity, variable volume dilatancy and post-peak hardening/softening strongly affect the predicted curves, resulting in corresponding differences of lining pressures in real tunnel excavations.

Crystallization engineering as a route to epitaxial strain control

Directory of Open Access Journals (Sweden)

Andrew R. Akbashev

2015-10-01

Full Text Available The controlled synthesis of epitaxial thin films offers opportunities for tuning their functional properties via enabling or suppressing strain relaxation. Examining differences in the epitaxial crystallization of amorphous oxide films, we report on an alternate, low-temperature route for strain engineering. Thin films of amorphous Bi–Fe–O were grown on (001SrTiO3 and (001LaAlO3 substrates via atomic layer deposition. In situ X-ray diffraction and X-ray photoelectron spectroscopy studies of the crystallization of the amorphous films into the epitaxial (001BiFeO3 phase reveal distinct evolution profiles of crystallinity with temperature. While growth on (001SrTiO3 results in a coherently strained film, the same films obtained on (001LaAlO3 showed an unstrained, dislocation-rich interface, with an even lower temperature onset of the perovskite phase crystallization than in the case of (001SrTiO3. Our results demonstrate how the strain control in an epitaxial film can be accomplished via its crystallization from the amorphous state.

The influence of temperature on low cycle fatigue behavior of prior cold worked 316L stainless steel (II) : life prediction and failure mechanism

International Nuclear Information System (INIS)

Hong, Seong Gu; Yoon, Sam Son; Lee, Soon Bok

2003-01-01

Tensile and low cycle fatigue tests on prior cold worked 316L stainless steel were carried out at various temperatures from room temperature to 650 deg. C. Fatigue resistance was decreased with increasing temperature and decreasing strain rate. Cyclic plastic deformation, creep, oxidation and interactions with each other are thought to be responsible for the reduction in fatigue resistance. Currently favored life prediction models were examined and it was found that it is important to select a proper life prediction parameter since stress-strain relation strongly depends on temperature. A phenomenological life prediction model was proposed to account for the influence of temperature on fatigue life and assessed by comparing with experimental result. LCF failure mechanism was investigated by observing fracture surfaces of LCF failed specimens with SEM

Toward a better understanding of strain incompatibilities at grain boundaries in the analysis of fatigue crack initiation at low temperature in the UdimetTM 720 Li superalloy

Directory of Open Access Journals (Sweden)

Larrouy Baptiste

2014-01-01

Full Text Available Low cycle fatigue properties of polycrystalline γ-γ′ Ni-based superalloys are dependent on many factors such as temperature, environment, grain size and distribution of the strengthening phases. Under LCF conditions at intermediate temperatures, an intergranular crack initiation could be observed. In this paper we propose to analyze the local conditions favouring such an intergranular cracking mode considering the high strength C&W UdimetTM720 Li alloy, widely used for manufacturing high pressure turbine disk for aeroengine applications. Tensile and fatigue tests were performed in air in the 20–465 ∘C range of temperature on micro-samples in order to focus on plasticity and damage processes developed near grain boundaries. A special attention was paid on the slip transfer between neighbouring grains taking into account their local crystallographic orientations. In some specific crystallographic configurations, small zones were detected at the tip of slip bands presenting an intense elastic/plastic activity. Although they are limited in size, they are associated to local crystalline rotations. High levels of local strain/stress were also evaluated in these volumes using an EBSD pattern cross correlation technique. The development of such specific zones was investigated at different stages of the tensile and LCF behaviour and was identified as leading to micro-cracks initiation for both solicitation modes.

Cyclic Elastoplastic Performance of Aluminum 7075-T6 Under Strain- and Stress-Controlled Loading

Science.gov (United States)

Agius, Dylan; Wallbrink, Chris; Kourousis, Kyriakos I.

2017-12-01

Elastoplastic investigations of aerospace aluminum are important in the development of an understanding of the possible cyclic transient effects and their contribution to the material performance under cyclic loading. Cyclic plasticity can occur in an aerospace aluminum component or structure depending on the loading conditions and the presence of external and internal discontinuities. Therefore, it is vital that the cyclic transient effects of aerospace aluminum are recognized and understood. This study investigates experimentally the cyclic elastoplastic performance of aluminum 7075-T6 loaded in symmetric strain control, and asymmetric stress and strain control. A combination of cyclic hardening and softening was noticed from high strain amplitude symmetric strain-controlled tests and at low stress amplitude asymmetric stress-controlled tests. From asymmetric strain control results, the extent of mean stress relaxation depended on the size of the strain amplitude. Additionally, saturation of the ratcheting strain (plastic shakedown) was also found to occur during asymmetric stress control tests. The experimental results were further analyzed using published microstructure research from the past two decades to provide added explanation of the micro-mechanism contribution to the cyclic transient behavior.

Elliptical posts allow for detailed control of non-equibiaxial straining of cell cultures

DEFF Research Database (Denmark)

Olesen, Christian Gammelgaard; Pennisi, Cristian Pablo; de Zee, Mark

2013-01-01

tissue cells in vivo are subjected to a range of mechanical deformations including shear strain caused by activities of daily living. Shear strains are suspected to play an important role in tissue necrosis. Method The Flexcell system was redesigned using a finite element model in order to obtain large...... areas of the membrane in a controlled, uniform non-equibiaxial strain state. Results The redesign was manufactured and the resulting strains were experimentally validated by means of image analysis methods. The results showed that the system could be used for experiments varying the shear strain....... Conclusion The result allows scientists and experimentalists to apply detailed control of the strain tensor applied to tissue samples in two dimensions....

CYCLIC PLASTIC BEHAVIOUR OF UFG COPPER UNDER CONTROLLED STRESS AND STRAIN LOADING

Directory of Open Access Journals (Sweden)

Lucie Navrátilová

2012-01-01

Full Text Available The influence of stress- and strain-controlled loading on microstructure and cyclic plastic behaviour of ultrafine-grained copper prepared by equal channel angular pressing was examined. The stability of microstructure is a characteristic feature for stress-controlled test whereas grain coarsening and development of bimodal structure was observed after plastic strain-controlled tests. An attempt to explain the observed behaviour was made.

Field-induced strain memory with non-180 .deg. domain-reorientation control

International Nuclear Information System (INIS)

Kadota, Yoichi; Hosaka, Hiroshi; Morita, Takeshi

2010-01-01

Using non-180 .deg. domain-reorientation control, we propose the strain memory effect in ferroelectric ceramics. Electric fields with asymmetric amplitudes were applied to soft-type lead zirconate titanate (PZT) ceramics, and the strain hysteresis and the polarization loop were measured. The butterfly curve became asymmetric under an electric field with a particular asymmetric amplitude. The asymmetric butterfly curve had two stable strain states at zero electric field. Thus, the strain memory effect was realized as the difference between the two stable strain states. An XRD analysis was carried out to verify the contribution of the non-180 .deg. domain reorientation to the strain memory effect. The non-180 .deg. domain reorientation was determined as the intensity ratio of the (002) to the (200) peak. The strain memory determined from macroscopic strain measurements had a linear relationship to the non-180 .deg. domain volume fraction. This result indicated the origin of the strain memory to be the non-180 .deg. domain reorientation.

Complete Genome Sequence of the Quality Control Strain Staphylococcus aureus subsp. aureus ATCC 25923.

Science.gov (United States)

Treangen, Todd J; Maybank, Rosslyn A; Enke, Sana; Friss, Mary Beth; Diviak, Lynn F; Karaolis, David K R; Koren, Sergey; Ondov, Brian; Phillippy, Adam M; Bergman, Nicholas H; Rosovitz, M J

2014-11-06

Staphylococcus aureus subsp. aureus ATCC 25923 is commonly used as a control strain for susceptibility testing to antibiotics and as a quality control strain for commercial products. We present the completed genome sequence for the strain, consisting of the chromosome and a 27.5-kb plasmid. Copyright © 2014 Treangen et al.

Fixed and mobile-bearing total ankle prostheses: Effect on tibial bone strain.

Science.gov (United States)

Terrier, Alexandre; Fernandes, Caroline Sieger; Guillemin, Maïka; Crevoisier, Xavier

2017-10-01

Total ankle replacement is associated to a high revision rate. To improve implant survival, the potential advantage of prostheses with fixed bearing compared to mobile bearing is unclear. The objective of this study was to test the hypothesis that fixed and mobile bearing prostheses are associated with different biomechanical quantities typically associated to implant failure. With a validated finite element model, we compared three cases: a prosthesis with a fixed bearing, a prosthesis with a mobile bearing in a centered position, and a prosthesis with mobile bearing in an eccentric position. Both prostheses were obtained from the same manufacturer. They were tested on seven tibias with maximum axial compression force during walking. We tested the hypothesis that there was a difference of bone strain, bone-implant interfacial stress, and bone support between the three cases. We also evaluated, for the three cases, the correlations between bone support, bone strain and bone-implant interfacial stress. There were no statistically significant differences between the three cases. Overall, bone support was mainly trabecular, and less effective in the posterior side. Bone strain and bone-implant interfacial stress were strongly correlated to bone support. Even if slight differences are observed between fixed and mobile bearing, it is not enough to put forward the superiority of one of these implants regarding their reaction to axial compression. When associated to the published clinical results, our study provides no argument to warn surgeons against the use of two-components fixed bearing implants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cooperative photoinduced metastable phase control in strained manganite films

Science.gov (United States)

Zhang, Jingdi; Tan, Xuelian; Liu, Mengkun; Teitelbaum, S. W.; Post, K. W.; Jin, Feng; Nelson, K. A.; Basov, D. N.; Wu, Wenbin; Averitt, R. D.

2016-09-01

A major challenge in condensed-matter physics is active control of quantum phases. Dynamic control with pulsed electromagnetic fields can overcome energetic barriers, enabling access to transient or metastable states that are not thermally accessible. Here we demonstrate strain-engineered tuning of La2/3Ca1/3MnO3 into an emergent charge-ordered insulating phase with extreme photo-susceptibility, where even a single optical pulse can initiate a transition to a long-lived metastable hidden metallic phase. Comprehensive single-shot pulsed excitation measurements demonstrate that the transition is cooperative and ultrafast, requiring a critical absorbed photon density to activate local charge excitations that mediate magnetic-lattice coupling that, in turn, stabilize the metallic phase. These results reveal that strain engineering can tune emergent functionality towards proximal macroscopic states to enable dynamic ultrafast optical phase switching and control.

The role of high cycle fatigue (HCF) onset in Francis runner reliability

International Nuclear Information System (INIS)

Gagnon, M; Tahan, S A; Bocher, P; Thibault, D

2012-01-01

High Cycle Fatigue (HCF) plays an important role in Francis runner reliability. This paper presents a model in which reliability is defined as the probability of not exceeding a threshold above which HCF contributes to crack propagation. In the context of combined Low Cycle Fatigue (LCF) and HCF loading, the Kitagawa diagram is used as the limit state threshold for reliability. The reliability problem is solved using First-Order Reliability Methods (FORM). A study case is proposed using in situ measured strains and operational data. All the parameters of the reliability problem are based either on observed data or on typical design specifications. From the results obtained, we observed that the uncertainty around the defect size and the HCF stress range play an important role in reliability. At the same time, we observed that expected values for the LCF stress range and the number of LCF cycles have a significant influence on life assessment, but the uncertainty around these values could be neglected in the reliability assessment.

Modulation of magnetic coercivity in Ni thin films by reversible control of strain

Energy Technology Data Exchange (ETDEWEB)

Lin, Wen-Chin, E-mail: wclin@ntnu.edu.tw [Department of Physics, National Taiwan Normal University, Taipei 116, Taiwan (China); Huang, Chia-Wei; Ting, Yi-Chieh; Lo, Fang-Yuh [Department of Physics, National Taiwan Normal University, Taipei 116, Taiwan (China); Chern, Ming-Yau [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China)

2015-05-01

In this study, we demonstrated the magnetoelectric control of magnetic thin films. (111)-textured Pd/Ni/Pd thin films were prepared on mica/lead zirconium titanate (PZT) substrates for the investigation. The reversible modulation of magnetic coercivity in Ni films was observed through the electric-voltage-controlled strain variation from the PZT substrate. For 14 nm Ni film, the applied electric field of ±350 V/m led to ±0.5% strain variation of PZT, which was transferred to ±0.4% strain variation of Pd/Ni/Pd thin films on mica, and resulted in ∓17 Oe (∓5% of the preliminary magnetic coercivity). The reversible modulation of magnetic coercivity is supposed to be caused by the voltage-controlled strain through the magneto-elastic effect. - Highlights: • The magnetoelectric control of the magnetic coercivity of Pd/Ni/Pd thin films was demonstrated. • The ±0.4% strain variation of 14 nm Ni thin films resulted in ±17 Oe change of H{sub c}. • The reversible modulation of H{sub c} is supposed to be caused by the magneto-elastic effect.

Differences in the cyclic deformation behaviour of quenched and tempered steel 42 CrMo 4 (AISI 4140) due to stress- and strain-control; Versuchsfuehrungsbedingte Unterschiede im zyklischen Verformungsverhalten von verguetetem 42 CrMo 4 bei Spannungs- und Totaldehnungskontrolle

Energy Technology Data Exchange (ETDEWEB)

Schulze, V.; Lang, K.-H.; Voehringer, O.; Macherauch, E. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Werkstoffkunde 1

1998-04-01

Cyclic stress-strain-curves and Manson-Coffin-plots of quenched and tempered steel 42 CrMo 4 (AISI 4140) strongly depend on whether they are determined under stress- or total-strain-control. At total-strain-controlled experiments, this is caused on the one hand by comparatively high initial stress-amplitudes which lead to distinctive cyclic work softening. On the other hand, the occuring differences in the evolution of inhomogeneous deformation patterns at both types of loading, which can be recorded by means of photoelasticity and microscopy, lead to differently distributed plastic deformations and to different integral values of plastic strain. (orig.) 11 refs.

Chemometric analysis of attenuated total reflectance infrared spectra of Proteus mirabilis strains with defined structures of LPS.

Science.gov (United States)

Zarnowiec, Paulina; Mizera, Andrzej; Chrapek, Magdalena; Urbaniak, Mariusz; Kaca, Wieslaw

2016-07-01

Proteus spp. strains are some of the most important pathogens associated with complicated urinary tract infections and bacteremia affecting patients with immunodeficiency and long-term urinary catheterization. For epidemiological purposes, various molecular typing methods have been developed for this pathogen. However, these methods are labor intensive and time consuming. We evaluated a new method of differentiation between strains. A collection of Proteus spp. strains was analyzed by attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy in the mid-infrared region. ATR FT-IR spectroscopy used in conjunction with a diamond ATR accessory directly produced the biochemical profile of the surface chemistry of bacteria. We conclude that a combination of ATR FT-IR spectroscopy and mathematical modeling provides a fast and reliable alternative for discrimination between Proteus isolates, contributing to epidemiological research. © The Author(s) 2016.

Native strains of Beauveria bassiana for the control of Rhipicephalus sanguineus sensu lato.

Science.gov (United States)

Cafarchia, Claudia; Immediato, Davide; Iatta, Roberta; Ramos, Rafael Antonio Nascimento; Lia, Riccardo Paolo; Porretta, Daniele; Figueredo, Luciana Aguiar; Dantas-Torres, Filipe; Otranto, Domenico

2015-02-05

Rhipicephalus sanguineus sensu lato ticks are widespread worldwide due to their adaptability to survive under different environmental conditions. They may act as vectors of a wide range of pathogens to humans and animals and their control is based on the use of chemical products on dogs and in the environment. Alternative control strategies, such as the use of entomopathogenic fungi as bio-control agents have also been investigated. The ability of native strains of Beauveria bassiana sensu lato in causing mortality in different tick species (e.g., Amblyomma cajennense and Rhipicephalus microplus) has been demonstrated. However, limited studies have assessed the use of B. bassiana for the control of R. sanguineus s.l. and none of them have employed native strains of this fungus. Here we investigated the pathogenicity of a native strain of B. bassiana (CD1123) against all developmental stages of R. sanguineus s.l.. Batches of eggs, larvae, nymphs and adult ticks were immersed in a suspension of 10(7) conidia/ml of B. bassiana s.l., isolated from a R. sanguineus s.l. engorged female. All treatment and control groups were observed for 20 days, and the biological parameters (i.e., mortality, hatching, moulting percentage, pre-oviposition period, oviposition period and rate, eggs production efficiency, reproductive efficiency and fitness indexes) were assessed. The effect of the B. bassiana strain tested herein on eggs, larvae, nymphs and adults showed a significantly higher mortality than those of the control groups (p bassiana strain is highly virulent towards all life-cycle developmental stages of R. sanguineus s.l. and may be of potential interest as a biological control agent against these ticks.

Improving sensitivity of the polyurethane/CNT laminate strain sensor by controlled mechanical preload

International Nuclear Information System (INIS)

Slobodian, Petr; Olejnik, Robert; Matyas, Jiri; Babar, Dipak Gorakh

2016-01-01

This article describes strain detection potential of polyurethane/CNT layered composite and further possible enhance of its sensitivity to strain, expressed by value of gauge factor, GF, employing its controlled mechanical preload. In course of its fabrication a non-woven polyurethane membrane made by electro spinning was used as filtering membrane for CNT aqueous dispersion. Final CNT polyurethane laminate composite is prepared by compression molding. Produced polyurethane/CNT composite laminate is electrically conductive and high elastic. Its elongation leads to change of its macroscopic electrical resistance. Changes in resistance are further reversible, reproducible and can monitor deformation in real time. Gauge factor reaches very high values around 8 for strain reaching 3.5% comparing with conventional metallic strain gauges. Finally, controlled mechanical preload significantly increases value of GF. For example for value of 8.1% of preload value of GF reaches 23.3 for strain 3.5%. (paper)

Advanced technology components for model GTP305-2 aircraft auxiliary power system. Final report 6 May 75-15 Jul 79

Energy Technology Data Exchange (ETDEWEB)

Kidwell, J.R.; Large, G.D.

1980-02-01

The GTP305-2 Advanced APU is a single shaft, all shaft power engine incorporating an axial-centrifugal compressor, a reverse flow annular combustor and a radial-axial turbine. Cycle analyses indicated a 10-percent high pressure compressor flow increase improved matching characteristics with the low pressure compressor. The combustion system is a reverse flow annular combustor with an air-assist/airblast fuel injection system. The radial-axial turbine stage is characterized by an integrally cast turbine rotor and a cast exhaust duct assembly. The Integrated Components Assembly (ICA) rig consists of the combustor and turbines with a dummy mass on the shaft to simulate the compressor. ICA testing was conducted to establish component performance at design operating conditions. ICA and cold air aerodynamic testing of the turbine stage and cooling flow effects, indicates design efficiency goals were exceeded. ICA test results, cold-air testing and combustion system parameters were input to the cycle model. Room temperature strain-control LCF tests were performed and results analyzed on a Weibull distribution. Data analysis indicated LCF life improvement was obtained through HIP and heat treatment.

Pseudomonas fluorescens strain CL145A - a biopesticide for the control of zebra and quagga mussels (Bivalvia: Dreissenidae).

Science.gov (United States)

Molloy, Daniel P; Mayer, Denise A; Gaylo, Michael J; Morse, John T; Presti, Kathleen T; Sawyko, Paul M; Karatayev, Alexander Y; Burlakova, Lyubov E; Laruelle, Franck; Nishikawa, Kimi C; Griffin, Barbara H

2013-05-01

Zebra mussels (Dreissena polymorpha) and quagga mussels (Dreissena rostriformis bugensis) are the "poster children" of high-impact aquatic invasive species. In an effort to develop an effective and environmentally acceptable method to control their fouling of raw-water conduits, we have investigated the potential use of bacteria and their natural metabolic products as selective biological control agents. An outcome of this effort was the discovery of Pseudomonas fluorescens strain CL145A - an environmental isolate that kills these dreissenid mussels by intoxication (i.e., not infection). In the present paper, we use molecular methods to reconfirm that CL145A is a strain of the species P. fluorescens, and provide a phylogenetic analysis of the strain in relation to other Pseudomonas spp. We also provide evidence that the natural product lethal to dreissenids is associated with the cell wall of P. fluorescens CL145A, is a heat-labile secondary metabolite, and has degradable toxicity within 24 h when applied to water. CL145A appears to be an unusual strain of P. fluorescens since it was the only one among the ten strains tested to cause high mussel mortality. Pipe trials conducted under once-through conditions indicated: (1) P. fluorescens CL145A cells were efficacious against both zebra and quagga mussels, with high mortalities achieved against both species, and (2) as long as the total quantity of bacterial cells applied during the entire treatment period was the same, similar mussel mortality could be achieved in treatments lasting 1.5-12.0 h, with longer treatment durations achieving lower mortalities. The efficacy data presented herein, in combination with prior demonstration of its low risk of non-target impact, indicate that P. fluorescens CL145A cells have significant promise as an effective and environmentally safe control agent against these invasive mussels. Copyright © 2012 Elsevier Inc. All rights reserved.

Ring strain and total syntheses of modified macrocycles of the isoplagiochin type

Directory of Open Access Journals (Sweden)

Andreas Speicher

2009-12-01

Full Text Available Macrocycles of the bisbibenzyl-type are natural products that are found exclusively in bryophytes (liverworts. The molecular framework of the subtype “isoplagiochin” is of substantial structural interest because of the chirality of the entire molecule, which arises from two biaryl axes in combination with two helical two-carbon units in a cyclic arrangement. From a structural as well as a synthetic point of view we report on the total synthesis of compounds which possess more rigid two-carbon biaryl bridges like stilbene (E or Z or even tolane moieties which were introduced starting with a Sonogashira protocol. The McMurry method proved to be a powerful tool for the cyclization to these considerably ring-strained macrocycles.

Strain and displacement controls by fibre bragg grating and digital image correlation

DEFF Research Database (Denmark)

Waldbjørn, Jacob Paamand; Høgh, Jacob Herold; Schmidt, Jacob Wittrup

2014-01-01

the test based on measurements performed directly on the test specimen. In this paper, fibre Bragg grating (FBG) and Digital Image Correlation (DIC) are used to control a test. The FBG sensors offer the possibility of measuring strains inside the specimen, while the DIC system measures strains...

Height control of self-assembled quantum dots by strain engineering during capping

NARCIS (Netherlands)

Grossi, D.; Smereka, P.; Keizer, J.G.; Ulloa, J.M.; Koenraad, P.M.

2014-01-01

Strain engineering during the capping of III-V quantum dots has been explored as a means to control the height of strained self-assembled quantum dots. Results of Kinetic Monte Carlo simulations are confronted with cross-sectional Scanning Tunnel Microscopy (STM) measurements performed on InAs

Cyclic life of superalloy IN738LC under in-phase and out-of-phase thermo-mechanical fatigue loading

International Nuclear Information System (INIS)

Chen Hongjun; Wahi, R.P.; Wever, H.

1995-01-01

The cyclic life of IN738LC, a widely used nickel base superalloy for blades in stationary gas turbines, was investigated under thermo-mechanical fatigue loading using a temperature variation range of 1023 to 1223 K, with temperature variation rate in the range of 6 to 15 K/min. Simple thermo-mechanical cycles with linear sequences corresponding to in-phase (IP) and out-of-phase (OP) tests were performed. Both the IP and OP tests were carried out at different constant mechanical strain ranges varied between 0.8 to 2.0% and at a constant mechanical strain rate of 10 -5 s -1 . Thermo-mechanical fatigue lives under both test conditions were compared with each other and with those of isothermal LCF tests at a temperature of 1223 K. The results show that the life under thermo-mechanical fatigue is strongly dependent on the nature of the test, i.e. stress controlled or strain controlled. (orig.)

Strain-controlled magnetic domain wall propagation in hybrid piezoelectric/ferromagnetic structures.

Science.gov (United States)

Lei, Na; Devolder, Thibaut; Agnus, Guillaume; Aubert, Pascal; Daniel, Laurent; Kim, Joo-Von; Zhao, Weisheng; Trypiniotis, Theodossis; Cowburn, Russell P; Chappert, Claude; Ravelosona, Dafiné; Lecoeur, Philippe

2013-01-01

The control of magnetic order in nanoscale devices underpins many proposals for integrating spintronics concepts into conventional electronics. A key challenge lies in finding an energy-efficient means of control, as power dissipation remains an important factor limiting future miniaturization of integrated circuits. One promising approach involves magnetoelectric coupling in magnetostrictive/piezoelectric systems, where induced strains can bear directly on the magnetic anisotropy. While such processes have been demonstrated in several multiferroic heterostructures, the incorporation of such complex materials into practical geometries has been lacking. Here we demonstrate the possibility of generating sizeable anisotropy changes, through induced strains driven by applied electric fields, in hybrid piezoelectric/spin-valve nanowires. By combining magneto-optical Kerr effect and magnetoresistance measurements, we show that domain wall propagation fields can be doubled under locally applied strains. These results highlight the prospect of constructing low-power domain wall gates for magnetic logic devices.

Controlled fermentation of Moroccan picholine green olives by oleuropein-degrading Lactobacilli strains

Energy Technology Data Exchange (ETDEWEB)

Ghabbour, N.; Rokni, Y.; Lamzira, Z.; Thonart, P.; Chihib, N.E.; Peres, C.; Asehraou, A.

2016-07-01

The control of the spontaneous fermentation process of un-debittered Moroccan Picholine green olives was undertaken basing the inoculation with two lactobacilli strains (Lactobacillus plantarum S175 and Lactobacillus pentosus S100). These strains, previously selected in our laboratory for their oleuropein-degrading capacity, were inoculated in olives brined at 5% of NaCl, and then incubated at 30 °C. The physico-chemical parameters (pH, free acidity, reducing sugars, sodium chloride, oleuropein and its hydrolysis products), and the microbiological parameters (mesophilic aerobic bacteria, coliforms, Staphylococcus, lactic acid bacteria and yeasts and moulds), were regularly analyzed during the fermentation time. The results obtained showed the effectiveness of the lactic acid bacteria strains to develop suitable oleuropein biodegradation and controlled lactic fermentation processes more than the un-inoculated olives (control). This result was confirmed by the rapid elimination of coliforms and staphylococcus, the accumulation of hydroxytyrosol as a result of oleuropein biodegradation, and a drastic reduction in spoiled olives with good quality fermented olives. (Author)

Multiferroic Properties of o-LuMnO3 Controlled by b-Axis Strain

Science.gov (United States)

Windsor, Y. W.; Huang, S. W.; Hu, Y.; Rettig, L.; Alberca, A.; Shimamoto, K.; Scagnoli, V.; Lippert, T.; Schneider, C. W.; Staub, U.

2014-10-01

Strain is a leading candidate for controlling magnetoelectric coupling in multiferroics. Here, we use x-ray diffraction to study the coupling between magnetic order and structural distortion in epitaxial films of the orthorhombic (o-) perovskite LuMnO3. An antiferromagnetic spin canting in the E-type magnetic structure is shown to be related to the ferroelectrically induced structural distortion and to a change in the magnetic propagation vector. By comparing films of different orientations and thicknesses, these quantities are found to be controlled by b-axis strain. It is shown that compressive strain destabilizes the commensurate E-type structure and reduces its accompanying ferroelectric distortion.

Experimental investigation on low cycle fatigue and creep-fatigue interaction of DZ125 in different dwell time at elevated temperatures

International Nuclear Information System (INIS)

Shi Duoqi; Liu Jinlong; Yang Xiaoguang; Qi Hongyu; Wang Jingke

2010-01-01

Research highlights: → This paper has researched creep-fatigue interaction of directionally solidified superalloy DZ125 with different dwell time at high temperature combined with micro-mechanism by experiment. → The results indicated that the life of creep-fatigue decreases as dwell time increases, but the life of this alloy was almost unchanged when dwell time exceeds a critical value at 850 deg. C. - Abstract: The low cycle fatigue (LCF) and creep-fatigue tests have been conducted with directionally solidified nickel-based superalloy DZ125 at 850 and 980 deg. C to study the creep-fatigue interaction behavior of alloy with different dwell time. On the average, the life of creep-fatigue tests are about 70% less than the life of LCF tests under the same strain range at 850 deg. C. The life of creep-fatigue decreases as dwell time increases, but the life of this alloy was almost unchanged when dwell time exceeds a critical value at 850 deg. C. Scanning electron microscope (SEM) analyses of the fracture revealed that the fracture modes were influenced by different way of loading. In case of LCF, the primary fracture mode was transgranular, while in case of creep-fatigue, the primary fracture mode was mixed with transgranular and intergranular. There were also obvious different morphologies of surface crack between LCF and creep-fatigue.

Genome sequences of three strains of Aspergillus flavus for the biological control of Aflatoxin

Science.gov (United States)

The genomes of three strains of Aspergillus flavus with demonstrated utility for the biological control of aflatoxin were sequenced. These sequences were assembled with MIRA and annotated with Augustus using A. flavus strain 3357 (NCBI EQ963472) as a reference. Each strain had a genome of 36.3 to ...

Multi-layered controllable stiffness beams for morphing: energy, actuation force, and material strain considerations

International Nuclear Information System (INIS)

Murray, Gabriel; Gandhi, Farhan

2010-01-01

Morphing aerospace structures could benefit from the ability of structural elements to transition from a stiff load-bearing state to a relatively compliant state that can undergo large deformation at low actuation cost. The present paper focuses on multi-layered beams with controllable flexural stiffness—comprising polymer layers affixed to the surfaces of a base beam and cover layers, in turn, affixed to the surfaces of the polymer layers. Heating the polymer through the glass transition reduces its shear modulus, decouples the cover layers from the base beam and reduces the overall flexural stiffness. Although the stiffness and actuation force required to bend the beam reduce, the energy required to heat the polymer layer must also be considered. Results show that for beams with low slenderness ratios, relatively thick polymer layers, and cover layers whose extensional stiffness is high, the decoupling of the cover layers through softening of the polymer layers can result in flexural stiffness reductions of over 95%. The energy savings are also highest for these configurations, and will increase as the deformation of the beam increases. The decoupling of the cover layers from the base beam through the softening of the polymer reduces the axial strains in the cover layers significantly; otherwise material failure would prevent large deformation. Results show that when the polymer layer is stiff, the cover layers are the dominant contributors to the total energy in the beam, and the energy in the polymer layers is predominantly axial strain energy. When the polymer layers are softened the energy in the cover layers is a small contributor to the total energy which is dominated by energy in the base beam and shear strain energy in the polymer layer

A Predictive Framework for Thermomechanical Fatigue Life of High Silicon Molybdenum Ductile Cast Iron Based on Considerations of Strain Energy Dissipation

Science.gov (United States)

Avery, Katherine R.

Isothermal low cycle fatigue (LCF) and anisothermal thermomechanical fatigue (TMF) tests were conducted on a high silicon molybdenum (HiSiMo) cast iron for temperatures up to 1073K. LCF and out-of-phase (OP) TMF lives were significantly reduced when the temperature was near 673K due to an embrittlement phenomenon which decreases the ductility of HiSiMo at this temperature. In this case, intergranular fracture was predominant, and magnesium was observed at the fracture surface. When the thermal cycle did not include 673K, the failure mode was predominantly transgranular, and magnesium was not present on the fracture surface. The in-phase (IP) TMF lives were unaffected when the thermal cycle included 673K, and the predominant failure mode was found to be transgranular fracture, regardless of the temperature. No magnesium was present on the IP TMF fracture surfaces. Thus, the embrittlement phenomenon was found to contribute to fatigue damage only when the temperature was near 673K and a tensile stress was present. To account for the temperature- and stress-dependence of the embrittlement phenomenon on the TMF life of HiSiMo cast iron, an original model based on the cyclic inelastic energy dissipation is proposed which accounts for temperature-dependent differences in the rate of fatigue damage accumulation in tension and compression. The proposed model has few empirical parameters. Despite the simplicity of the model, the predicted fatigue life shows good agreement with more than 130 uniaxial low cycle and thermomechanical fatigue tests, cyclic creep tests, and tests conducted at slow strain rates and with hold times. The proposed model was implemented in a multiaxial formulation and applied to the fatigue life prediction of an exhaust manifold subjected to severe thermal cycles. The simulation results show good agreement with the failure locations and number of cycles to failure observed in a component-level experiment.

Monitoring Leptospira strain collections: the need for quality control

NARCIS (Netherlands)

Cerqueira, Gustavo M.; McBride, Alan J. A.; Queiroz, Adriano; Pinto, Luciano S.; Silva, Everton F.; Hartskeerl, Rudy A.; Reis, Mitermayer G.; Ko, Albert I.; Dellagostin, Odir A.

2010-01-01

The purpose of this study was to perform a 16S sequence-based quality control of two Leptospira strain collections. 16S rRNA gene sequencing was used to verify two Leptospira reference collections provided by the World Health Organization and maintained at a reference laboratory for leptospirosis in

Control of biaxial strain in single-layer molybdenite using local thermal expansion of the substrate

Science.gov (United States)

Plechinger, Gerd; Castellanos-Gomez, Andres; Buscema, Michele; van der Zant, Herre S. J.; Steele, Gary A.; Kuc, Agnieszka; Heine, Thomas; Schüller, Christian; Korn, Tobias

2015-03-01

Single-layer MoS2 is a direct-gap semiconductor whose electronic band structure strongly depends on the strain applied to its crystal lattice. While uniaxial strain can be easily applied in a controlled way, e.g., by bending of a flexible substrate with the atomically thin MoS2 layer on top, experimental realization of biaxial strain is more challenging. Here, we exploit the large mismatch between the thermal expansion coefficients of MoS2 and a silicone-based substrate to apply a controllable biaxial tensile strain by heating the substrate with a focused laser. The effect of this biaxial strain is directly observable in optical spectroscopy as a redshift of the MoS2 photoluminescence. We also demonstrate the potential of this method to engineer more complex strain patterns by employing highly absorptive features on the substrate to achieve non-uniform heat profiles. By comparison of the observed redshift to strain-dependent band structure calculations, we estimate the biaxial strain applied by the silicone-based substrate to be up to 0.2%, corresponding to a band gap modulation of 105 meV per percentage of biaxial tensile strain.

Influence of Thermal Aging on Tensile and Low Cycle Fatigue Behavior of Type 316LN Austenitic Stainless Steel Weld Joint

Science.gov (United States)

Suresh Kumar, T.; Nagesha, A.; Ganesh Kumar, J.; Parameswaran, P.; Sandhya, R.

2018-05-01

Influence of short-term thermal aging on the low-cycle fatigue (LCF) behavior of 316LN austenitic stainless steel weld joint with 0.07 wt pct N has been investigated. Prior thermal exposure was found to improve the fatigue life compared with the as-welded condition. Besides, the treatment also imparted a softening effect on the weld metal, leading to an increase in the ductility of the weld joint which had a bearing on the cyclic stress response. The degree of cyclic hardening was seen to increase after aging. Automated ball-indentation (ABI) technique was employed toward understanding the mechanical properties of individual zones across the weld joint. It was observed that the base metal takes most of the applied cyclic strain during LCF deformation in the as-welded condition. In the aged condition, however, the weld also participates in the cyclic deformation. The beneficial effect of thermal aging on cyclic life is attributed to a reduction in the severity of the metallurgical notch leading to a restoration of ductility of the weld region. The transformation of δ-ferrite to σ-phase during the aging treatment was found to influence the location of crack initiation. Fatigue cracks were found to initiate in the base metal region of the joint in most of the testing conditions. However, embrittlement in the weld metal caused a shift in the point of crack initiation with increasing strain amplitude under LCF.

Pressure management of water distribution systems via the remote real-time control of variable speed pumps

CSIR Research Space (South Africa)

Page, Philip R

2017-08-01

Full Text Available describes controllers which set the pump speed α, a physical property of the pump. The “proportional control” method (denoted PC), in analogy to the method for PCVs [2, 3, 12, 13], adjusts αi+1 = αi − kpi (Hi −Hsp) (3) where kpi is a dimension-full parameter... constant) Kpi in Eq. 6. An analogous procedure was followed for a PCV [13]. The proposed controller is called the “parameter-dependent P-controller with known constant pump flow” (DCF). The LCF and DCF controllers require Q to be known, either through a...

Life table and male mating competitiveness of wild type and of a chromosome mutation strain of Tetranychus urticae in relation to genetic pest control

International Nuclear Information System (INIS)

Feldmann, A.M.

1981-01-01

Males of Tetranychus urticae Koch (Acarina: Tetranychidae) from a strain, homozygous for a structural chromosome mutation (T) were competed against males from a standard (wild-type) strain for mating of wild-type fermales. The T-males exhibited only a slight reduction in male mating competitiveness. The debilitating influence of ageing on male mating competitiveness was equal for males of both strains. Life-table studies on both strains showed that the net reproductive rate (R 0 ) of the T-strain was 53.3, which was higher than the R 0 -value of the standard strain (43.3). This difference was caused by the higher rate of age-dependent mortality of adult females of the standard strain. Also differences between both strains in the total sex-ratio were observed; the T-strain produced significantly fewer males and more females than the standard strain. The mean generation time of both strains was almost equal (14 days). The values of the intrinsic rate of increase (rsub(m)) for the T-strain and the standard strain were 0.286 and 0.273, respectively. The life-table data correspond well with those published elsewhere on Tetranychus urticae. The feasibility of T-strains for application in genetic pest control considering the use of structural chromosome mutations as a 'transport mechanism' for conditional lethals is discussed. (orig.)

Learning and strain among newcomers: a three-wave study on the effects of job demands and job control.

Science.gov (United States)

Taris, Toon W; Feij, Jan A

2004-11-01

The present 3-wave longitudinal study was an examination of job-related learning and strain as a function of job demand and job control. The participants were 311 newcomers to their jobs. On the basis of R. A. Karasek and T. Theorell's (1990) demand-control model, the authors predicted that high demand and high job control would lead to high levels of learning; low demand and low job control should lead to low levels of learning; high demand and low job control should lead to high levels of strain; and low demand and high job control should lead to low levels of strain. The relation between strain and learning was also examined. The authors tested the hypotheses using ANCOVA and structural equation modeling. The results revealed that high levels of strain have an adverse effect on learning; the reverse effect was not confirmed. It appears that Karasek and Theorell's model is very relevant when examining work socialization processes.

Mechanical behaviour of aluminium–lithium alloys

Indian Academy of Sciences (India)

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

to their low ductility (Lin et al 1982; Sanders & Starke 1982, 1989; Gregson & Flower 1985;. Vasudevan ...... same in the lower strain amplitude region are found to be dependent on alloy chemistry and processing history. A comparison of the results from these studies has shown that anisotropy in the LCF properties is far ...

Aeroelastic Control of a Segmented Trailing Edge Using Fiber Optic Strain Sensing Technology

Science.gov (United States)

Graham, Corbin Jay; Martins, Benjamin; Suppanade, Nathan

2014-01-01

Currently, design of aircraft structures incorporate a safety factor which is essentially an over design to mitigate the risk of structure failure during operation. Typically this safety factor is to design the structure to withstand loads much greater than what is expected to be experienced during flight. NASA Dryden Flight Research Centers has developed a Fiber Optic Strain Sensing (FOSS) system which can measure strain values in real-time. The Aeroelastics Lab at the AERO Institute is developing a segmented trailing edged wing with multiple control surfaces that can utilize the data from the FOSS system, in conjunction with an adaptive controller to redistribute the lift across a wing. This redistribution can decrease the amount of strain experienced by the wing as well as be used to dampen vibration and reduce flutter.

Beauveria bassiana strains for biological control of Cosmopolites sordidus (Germ.) (Coleoptera: Curculionidae) in plantain.

Science.gov (United States)

Fancelli, Marilene; Dias, Alex Batista; Delalibera, Italo; de Jesus, Sandra Cerqueira; do Nascimento, Antonio Souza; Silva, Sebastião de Oliveira e; Caldas, Ranulfo Correa; Ledo, Carlos Alberto da Silva

2013-01-01

The objective of this study was to select strains of Beauveria bassiana for controlling Cosmopolites sordidus (Germ.) in plantain farms (cv. Terra) of the "Recôncavo" and southern regions in the state of Bahia, Brazil. The virulence of 32 B. bassiana isolates against C. sordidus was determined under laboratory conditions. Three isolates (CNPMF 407, CNPMF 218, and CNPMF 416) were selected for evaluation under field conditions in plantations located in the counties of Mutuípe and Wenceslau Guimarães. Population of C. sordidus was estimated every 15 days by using pseudostem traps. The efficiency of the three strains of B. bassiana was compared to chemical control (carbofuran, 4 g/trap) and absence of control. Carbofuran caused around 90% of adult mortality after 12 months, with a reduction in the population of C. sordidus since the first evaluation. A low number of trapped insects was observed in the fungus-treated plots, suggesting the efficiency of the isolates in controlling the C. sordidus population. The strain CNPMF 218 was the most efficient in controlling C. sordidus adults in both locations, causing around 20% mortality, leading to 40% population size reduction after 12 months.

Beauveria bassiana Strains for Biological Control of Cosmopolites sordidus (Germ. (Coleoptera: Curculionidae in Plantain

Directory of Open Access Journals (Sweden)

Marilene Fancelli

2013-01-01

Full Text Available The objective of this study was to select strains of Beauveria bassiana for controlling Cosmopolites sordidus (Germ. in plantain farms (cv. Terra of the “Recôncavo” and southern regions in the state of Bahia, Brazil. The virulence of 32 B. bassiana isolates against C. sordidus was determined under laboratory conditions. Three isolates (CNPMF 407, CNPMF 218, and CNPMF 416 were selected for evaluation under field conditions in plantations located in the counties of Mutuípe and Wenceslau Guimarães. Population of C. sordidus was estimated every 15 days by using pseudostem traps. The efficiency of the three strains of B. bassiana was compared to chemical control (carbofuran, 4g/trap and absence of control. Carbofuran caused around 90% of adult mortality after 12 months, with a reduction in the population of C. sordidus since the first evaluation. A low number of trapped insects was observed in the fungus-treated plots, suggesting the efficiency of the isolates in controlling the C. sordidus population. The strain CNPMF 218 was the most efficient in controlling C. sordidus adults in both locations, causing around 20% mortality, leading to 40% population size reduction after 12 months.

Low-cycle fatigue and damage of an uncoated and coated single crystal nickel-base superalloy SCB

International Nuclear Information System (INIS)

Stekovic, S.; Ericsson, T.

2007-01-01

This paper presents low-cycle fatigue (LCF) behaviour and damage mechanisms of uncoated and coated specimens of a single crystal nickel-base superalloy SCB tested at 500 C and 900 C. Four coatings were deposited on the base material, an overlay coating AMDRY997, a platinum-modified aluminide diffusion coating RT22 and two innovative coatings called IC1 and IC3 with a NiW diffusion barrier in the interface. AMDRY997 and RT22 were used as reference coatings. The LCF tests were performed at three strain amplitudes, 1.0, 1.2 and 1.4%, with R = -1, in laboratory air and without any dwell time. The LCF life of the specimens is determined by crack initiation and propagation. Crack data are presented for different classes of crack size in the form of crack density, that is, the number of cracks normalised to the investigated interface length. Micrographs of damage of the coatings are also shown. The effect of the coatings on the LCF life of the superalloy was dependent on the test temperature and deposited coating. At 500 C all coatings had a detrimental effect on the LCF life of the superalloy. At 900 C both AMDRY997 and IC1 prolonged the fatigue life of the superalloy by factors ranging between 1.5 and 4 while RT22 and IC3 shortened the life of the coating-substrate system. Specimens coated with RT22 exhibited generally more damage than other tested coatings at 900 C. Most of the cracks observed initiated at the coating surface and a majority were arrested in the interdiffusion zone between the base material and the coating. No topologically close-packed phases were found. Delamination was only found in AMDRY997 at higher strains. Surface roughness or rumpling was found in the overlay coating AMDRY997 with some cracks initiating from the rumples. The failure morphology at 900 C reflected the role of oxidation in the fatigue life, the crack initiation and propagation of the coated specimens. The wake of the cracks grown into the substrate was severely oxidised leading to

[Characterization of a bacterial biocontrol strain 1404 and its efficacy in controlling postharvest citrus anthracnose].

Science.gov (United States)

Wang, Qian; Hu, Chunjin; Ke, Fanggang; Huang, Siliang; Li, Qiqin

2010-09-01

Anthracnose caused by Colletotrichum gloeosporioides (Penz.) Sacc. is a main disease in citrus production. To develop an effective biocontrol measure against citrus postharvest anthracnose, we screened antagonistic microbes and obtained a bacterial strain 1404 from the rhizospheric soil of chili plants in Nanning city, Guangxi, China. The objectives of the present study were to: (1) identify and characterize the antagonistic bacterium; and (2) to evaluate the efficacy of the antagonistic strain in controlling citrus postharvest anthracnose disease. Strain 1404 was identified by comparing its 16S rDNA sequence with related bacteria from GenBank database, as well as analyzing its morphological, physiological and biochemical characters. The antagonistic stability of the strain 1404 was determined by continuously transferring it on artificial media. The effect of the strain on suppressing citrus anthracnose at postharvest stage was tested by stab inoculation method. The 16S rDNA of strain 1404 was amplified with primers PF1 (5'-AGAGTTTGATCATGGCTCAG-3') and PR1 (5'-TACGGTTACCTTGTTACGACTT-3') and its sequence submitted to GenBank (accession number: GU361113). Strain 1404 clustered with the GenBank-derived Brevibacillus brevis strains in the 16S-rDNA-sequence-based phylogenetic tree at 100% bootstrap level. The morphological traits, physiological and biochemical characters of strain 1404 agreed with that of Brevibacillus brevis. Less change in the suppressive ability of antagonist against growth of Colletotrichum gloeosporioides was observed during four continuous transfers on artificial media. The average control efficacy of the strain was 64. 9 % against the disease 20 days after the antagonist application. Strain 1404 was identified as Brevibacillus brevis based on its morphological traits, phyiological and biochemical characters as well as 16S rDNA sequence analysis. The antagonist was approved to be a promising biocontrol agent. This is the first report of

Controlling the exciton energy of a nanowire quantum dot by strain fields

Energy Technology Data Exchange (ETDEWEB)

Chen, Yan; Zhang, Jiaxiang; Ding, Fei, E-mail: f.ding@ifw-dresden.de [Institute for Integrative Nanosciences, IFW Dresden, Helmholtz Strasse 20, 01069 Dresden (Germany); Zadeh, Iman Esmaeil; Jöns, Klaus D.; Fognini, Andreas; Zwiller, Val [Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft (Netherlands); Reimer, Michael E. [Institute for Quantum Computing and Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, N2L 3G1 (Canada); Dalacu, Dan; Poole, Philip J. [National Research Council, Ottawa, Ontario K1A 0R6 (Canada); Schmidt, Oliver G. [Institute for Integrative Nanosciences, IFW Dresden, Helmholtz Strasse 20, 01069 Dresden (Germany); Material Systems for Nanoelectronics, Chemnitz University of Technology, Reichenhainer Strasse 70, 09107 Chemnitz (Germany)

2016-05-02

We present an experimental route to engineer the exciton energies of single quantum dots in nanowires. By integrating the nanowires onto a piezoelectric crystal, we controllably apply strain fields to the nanowire quantum dots. Consequently, the exciton energy of a single quantum dot in the nanowire is shifted by several meVs without degrading its optical intensity and single-photon purity. Second-order autocorrelation measurements are performed at different strain fields on the same nanowire quantum dot. The suppressed multi-photon events at zero time delay clearly verify that the quantum nature of single-photon emission is well preserved under external strain fields. The work presented here could facilitate on-chip optical quantum information processing with the nanowire based single photon emitters.

Quality parameters and RAPD-PCR differentiation of commercial baker's yeast and hybrid strains.

Science.gov (United States)

El-Fiky, Zaki A; Hassan, Gamal M; Emam, Ahmed M

2012-06-01

Baker's yeast, Saccharomyces cerevisiae, is a key component in bread baking. Total of 12 commercial baker's yeast and 2 hybrid strains were compared using traditional quality parameters. Total of 5 strains with high leavening power and the 2 hybrid strains were selected and evaluated for their alpha-amylase, maltase, glucoamylase enzymes, and compared using random amplified polymorphic DNA (RAPD). The results revealed that all selected yeast strains have a low level of alpha-amylase and a high level of maltase and glucoamylase enzymes. Meanwhile, the Egyptian yeast strain (EY) had the highest content of alpha-amylase and maltase enzymes followed by the hybrid YH strain. The EY and YH strains have the highest content of glucoamylase enzyme almost with the same level. The RAPD banding patterns showed a wide variation among commercial yeast and hybrid strains. The closely related Egyptian yeast strains (EY and AL) demonstrated close similarity of their genotypes. The 2 hybrid strains were clustered to Turkish and European strains in 1 group. The authors conclude that the identification of strains and hybrids using RAPD technique was useful in determining their genetic relationship. These results can be useful not only for the basic research, but also for the quality control in baking factories. © 2012 Institute of Food Technologists®

Control of strain in GaN by a combination of H2 and N2 carrier gases

International Nuclear Information System (INIS)

Yamaguchi, Shigeo; Kariya, Michihiko; Kosaki, Masayoshi; Yukawa, Yohei; Nitta, Shugo; Amano, Hiroshi; Akasaki, Isamu

2001-01-01

We study the effect of a combination of N 2 and H 2 carrier gases on the residual strain and crystalline properties of GaN, and we propose its application to the improvement of crystalline quality of GaN/Al 0.17 Ga 0.83 N multiple quantum well (MQW) structures. GaN was grown with H 2 or N 2 carrier gas (H 2 - or N 2 - GaN) on an AlN low-temperature-deposited buffer layer. A (0001) sapphire substrate was used. N 2 - GaN was grown on H 2 - GaN. The total thickness was set to be 1.5 μm, and the ratio of N 2 - GaN thickness to the total thickness, x, ranged from 0 to 1. With increasing x, the tensile stress in GaN increased. Photoluminescence intensity at room temperature was much enhanced. Moreover, the crystalline quality of GaN/Al 0.17 Ga 0.83 N MQW was much higher when the MQW was grown with N 2 on H 2 - GaN than when it was grown with H 2 on H 2 - GaN. These results were due to the achievement of control of strain in GaN using a combination of N 2 - GaN and H 2 - GaN. [copyright] 2001 American Institute of Physics

Deformable trailing edge flaps for modern megawatt wind turbine controllers using strain gauge sensors

DEFF Research Database (Denmark)

Andersen, Peter Bjørn; Henriksen, Lars Christian; Gaunaa, Mac

2010-01-01

. By enabling the trailing edge to move independently and quickly along the spanwise position of the blade, local small flutuations in the aerodynamic forces can be alleviated by deformation of the airfoil flap. Strain gauges are used as input for the flap controller, and the effect of placing strain gauges......The present work contains a deformable trailing edge flap controller integrated in a numerically simulated modern, variablespeed, pitch-regulated megawatt (MW)-size wind turbine. The aeroservoelastic multi-body code HAWC2 acts as a component in the control loop design. At the core of the proposed...... edge flaps on a wind turbine blade rather than a conclusive control design with traditional issues like stability and robustness fully investigated. Recent works have shown that the fatigue load reduction by use of trailing edge flaps may be greater than for traditional pitch control methods...

Controlled Autolysis and Enzyme Release in a Recombinant Lactococcal Strain Expressing the Metalloendopeptidase Enterolysin A

Science.gov (United States)

Hickey, Rita M.; Ross, R. Paul; Hill, Colin

2004-01-01

This study concerns the exploitation of the lytic enzyme enterolysin A (EntL), produced by Enterococcus faecalis strain DPC5280, to elicit the controlled autolysis of starter lactococci. EntL, a cell wall metalloendopeptidase secreted by some E. faecalis strains, can kill a wide range of gram-positive bacteria, including lactococci. The controlled expression of entL, which encodes EntL, was achieved using a nisin-inducible expression system in a lactococcal host. Zymographic analysis of EntL activity demonstrated that active enzyme is produced by the recombinant lactococcal host. Indeed, expression of EntL resulted in almost complete autolysis of the host strain 2 h after induction with nisin. Model cheese experiments using a starter strain in addition to the inducible enterolysin-producing strain showed a 27-fold increase in activity with respect to the release of lactate dehydrogenase in the strain overexpressing EntL, demonstrating the potential of EntL production in large-scale cheese production systems. Indeed, the observation that a wide range of lactic bacteria are sensitive to EntL suggests that EntL-induced autolysis has potential applications with a variety of lactic acid bacteria and could be a basis for probiotic delivery systems. PMID:15006800

Stress-strain properties of railway steel at strain rates of upto 105 per second

International Nuclear Information System (INIS)

Hashmi, M.S.J.; Islam, M.N.

1985-01-01

This paper presents the stress-strain characteristics of railway steel at strain rates of up to 10 5 /s at room temperature determined by a new technique. In determining the results, account has been taken of the strain-rate variation, the total strain and the strain rate history. The effect of friction, material inertia and temperature rise is also assessed and an empirical constitutive equation describing the strain-rate and strain sensitive flow stress for this type of steel is proposed. (orig.)

Prevention of brittle fracture of steel structures by controlling the local stress and strain fields

Directory of Open Access Journals (Sweden)

Moyseychik Evgeniy Alekseevich

Full Text Available In the article the author offers a classification of the methods to increase the cold resistance of steel structural shapes with a focus on the regulation of local fields of internal stresses and strains to prevent brittle fracture of steel structures. The need of a computer thermography is highlighted not only for visualization of temperature fields on the surface, but also to control the fields of residual stresses and strains in a controlled element.

O uso de Picibanil (OK-432 no tratamento do linfangioma de cabeça e pescoço

Directory of Open Access Journals (Sweden)

Mello-Filho Francisco V.

2002-01-01

Full Text Available Introdução e Objetivo: O Linfangioma Cérvico-Facial (LCF é geralmente um tumor volumoso, envolvendo estruturas importantes da face e do pescoço. A terapia habitualmente recomendada é a retirada cirúrgica, porém, esta é geralmente seguida de seqüelas importantes, causando deformidade da região. Com o objetivo de avaliarmos uma terapêutica alternativa, analisamos a eficiência do Picibanil (OK 432 no tratamento de LCF em crianças. Forma de Estudo: Clínico retrospectivo. Material e Método: Estudo retrospectivo de seis crianças com diagnóstico de LCF tratadas com OK-432 no HCFMRP-USP no período de 1997 a 2001. Foram analisadas as seguintes características dos LCF: dimensões, tipos de cistos e volume aspirado. Avaliamos, também, o número de aplicações de OK 432 com os respectivos intervalos de tempo utilizados, sua evolução, intercorrências e o resultado final do tratamento. Resultados: Os LCFs apresentavam de oito a 15cm em seu maior diâmetro, na ocasião da primeira consulta, sendo o tipo de cisto mais freqüentemente encontrado o tipo macro cisto. O volume de liquido aspirado variou de dois a 60 ml e o número de aplicações de uma a cinco vezes em intervalos variáveis de um mês a um ano. Em todos os pacientes ocorreu regressão da massa tumoral, sendo que em três houve o desaparecimento total do LCF. A única intercorrência observada foi febre em media de 38.2º C em todos pacientes. Conclusão: O OK 432 é uma droga segura, eficaz e que pode ser utilizada como medida de primeira escolha no tratamento do LCF.

Mechanical control over valley magnetotransport in strained graphene

Energy Technology Data Exchange (ETDEWEB)

Ma, Ning, E-mail: maning@stu.xjtu.edu.cn [Department of Physics, MOE Key Laboratory of Advanced Transducers and Intelligent Control System, Taiyuan University of Technology, Taiyuan 030024 (China); Department of Applied Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049 (China); Zhang, Shengli, E-mail: zhangsl@mail.xjtu.edu.cn [Department of Applied Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049 (China); Liu, Daqing, E-mail: liudq@cczu.edu.cn [School of Mathematics and Physics, Changzhou University, Changzhou 213164 (China)

2016-05-06

Recent experiments report that the graphene exhibits Landau levels (LLs) that form in the presence of a uniform strain pseudomagnetic field with magnitudes up to hundreds of tesla. We further reveal that the strain removes the valley degeneracy in LLs, and leads to a significant valley polarization with inversion symmetry broken. This accordingly gives rise to the well separated valley Hall plateaus and Shubnikov–de Haas oscillations. These effects are absent in strainless graphene, and can be used to generate and detect valley polarization by mechanical means, forming the basis for the new paradigm “valleytronics” applications. - Highlights: • We explore the mechanical strain effects on the valley magnetotransport in graphene. • We analytically derive the dc collisional and Hall conductivities under strain. • The strain removes the valley degeneracy in Landau levels. • The strain causes a significant valley polarization with inversion symmetry broken. • The strain leads to the well separated valley Hall and Shubnikov–de Haas effects.

Flux control-based design of furfural-resistance strains of Saccharomyces cerevisiae for lignocellulosic biorefinery.

Science.gov (United States)

Unrean, Pornkamol

2017-04-01

We have previously developed a dynamic flux balance analysis of Saccharomyces cerevisiae for elucidation of genome-wide flux response to furfural perturbation (Unrean and Franzen, Biotechnol J 10(8):1248-1258, 2015). Herein, the dynamic flux distributions were analyzed by flux control analysis to identify target overexpressed genes for improved yeast robustness against furfural. The flux control coefficient (FCC) identified overexpressing isocitrate dehydrogenase (IDH1), a rate-controlling flux for ethanol fermentation, and dicarboxylate carrier (DIC1), a limiting flux for cell growth, as keys of furfural-resistance phenotype. Consistent with the model prediction, strain characterization showed 1.2- and 2.0-fold improvement in ethanol synthesis and furfural detoxification rates, respectively, by IDH1 overexpressed mutant compared to the control. DIC1 overexpressed mutant grew at 1.3-fold faster and reduced furfural at 1.4-fold faster than the control under the furfural challenge. This study hence demonstrated the FCC-based approach as an effective tool for guiding the design of robust yeast strains.

Peri-implant bone strains and micro-motion following in vivo service: a postmortem retrieval study of 22 tibial components from total knee replacements.

Science.gov (United States)

Mann, Kenneth A; Miller, Mark A; Goodheart, Jacklyn R; Izant, Timothy H; Cleary, Richard J

2014-03-01

Biological adaptation following placement of a total knee replacements (TKRs) affects peri-implant bone mineral density (BMD) and implant fixation. We quantified the proximal tibial bone strain and implant-bone micro-motion for functioning postmortem retrieved TKRs and assessed the strain/micro-motion relationships with chronological (donor age and time in service) and patient (body weight and BMD) factors. Twenty-two tibial constructs were functionally loaded to one body weight (60% medial/40% lateral), and the bone strains and tray/bone micro-motions were measured using a digital image correlation system. Donors with more time in service had higher bone strains (p = 0.044), but there was not a significant (p = 0.333) contribution from donor age. Donors with lower peri-implant BMD (p = 0.0039) and higher body weight (p = 0.0286) had higher bone strains. Long term implants (>11 years) had proximal bone strains 900 µϵ that were almost twice as high as short term (implants 570 µϵ. Micro-motion was greater for younger donors (p = 0.0161) and longer time in service (p = 0.0008). Increased bone strain with long term in vivo service could contribute to loosening of TKRs by failure of the tibial peri-implant bone. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Nodulation and N2 fixation effectiveness of Bradyrhizobium strains in symbiosis with Adzuki Bean, Vigna angularis

Directory of Open Access Journals (Sweden)

Dušica Delić

2010-04-01

Full Text Available In pot experiment, one isolate Knj from a Serbian soil, four strains of Bradyrhizobium japonicum and three strains of Bradyrhizobium spp. were examined for the effect on adzuki bean nodulation and effectiveness in symbiotic N2 fixation. All the tested strains produced root nodules in adzuki bean. Strains of B. japonicum showed high potential of N2 fixation, particularly 525 and 542. B. japonicum strains resulted 65-71% shoot dry weight and 99-138% total N content of uninoculated control with full N content (100%. No significant difference was found between the plants inoculated with Bradyrhizobium spp. strains and uninoculated control plants without N (40-42 and 42% shoot dry weight, respectively, which indicated symbiotic N2 fixation inactivity of the Bradyrhizobium spp. strains. Knj strain had the middle position (56% shoot dry weight. These data showed that B. japonicum 525 and 542 strains could be used in further investigations in order to apply them as inoculants in microbiological N fertilizers.

Design of triaxial test with controlled suction: measure of strain

International Nuclear Information System (INIS)

Gasc-Barbier, M.; Cosenza, Ph.; Ghoreychi, M.; Chanchole, S.; Cosenza, Ph.; Tessier, D.

2000-01-01

Experimental study of mechanical behavior of clayey materials under hygrometric condition is usually performed either on unloaded samples or by means of classical odometer tests used in soil mechanics. Such methods are not well adapted to hard deep clayey rocks with little deformability, porosity and permeability. Moreover, stress and strain tensors having a significant effect on hygro-mechanical behaviour and properties cannot be measured and investigated appropriately by classical tests. This is why a specific triaxial test was designed in which the sample is surrounded by a fiber glass tissue allowing air circulation and then by silicon on which confining pressure is applied. Thus, equilibrium between air and sample was reduced. Stress and strain tensors were also measured in time on the sample subjected to a mechanical loading and to a controlled suction. After presentation of the test, preliminary results are given. (authors)

Evaluation of Trichoderma spp. strains for control yellowing pea caused by Fusarium oxysporum

Directory of Open Access Journals (Sweden)

Christian Eraso Insuasty

2014-07-01

Full Text Available The yellowing of pea caused by the fungus Fusarium oxysporum f. sp. pisi is considered the most damaging disease of this crop. This study took place at the plant health laboratory and greenhouse of the Universidad de Nariño, and the experimental stage was conducted at the Granja experimental Botana. Its purpose was to evaluate the antagonistic ability of the fungi Trichoderma spp. to F. oxysporum. Isolation of F. oxysporum was made from diseased tissue; Trichoderma strains were obtained from the rhizosphere of healthy plants (collected in the towns of Potosi, Córdoba, Gualmatán, Ipiales and Puerres in the state of Nariño, Colombia, and a commercial strain from laboratory Perkins Ltda. In laboratory, unrestrictedly randomized design with 21 treatments (strains was used. Mycelial growth and inhibition zone were evaluated in dual plantings, which served as selection criteria for greenhouse test where plant height, root length, root dry matter and percentage of incidence were evaluated. In the field, a randomized block design was used to evaluate yield components, plant height and root length with the best strains. In the laboratory, C2 (Córdoba 2, C7 (Gualmatán 3, C14 (Puerres 2, C20 (Potosi 4 and C21 (Perkins Lab. showed antagonistic activity in the greenhouse, C7, C14 and C21 were the best; in field, significant differences between C14 and C21, compared to C7 and the control, were obtained. Strains C14 and C21 have consistent antagonistic capacity and can be used to control F. oxysporum in pea.

The effects of probiotics on total cholesterol: A meta-analysis of randomized controlled trials.

Science.gov (United States)

Wang, Lang; Guo, Mao-Juan; Gao, Qing; Yang, Jin-Feng; Yang, Lin; Pang, Xiao-Li; Jiang, Xi-Juan

2018-02-01

Probiotics supplements provide a new nonpharmacological alternative to reduce cardiovascular risk factors. The impact of probiotics on the reduction of total cholesterol (TC) remains controversial. We conducted a meta-analysis to showcase the most updated and comprehensive evaluation of the studies. Randomized controlled trials (RCTs) were searched from electronic databases, including PubMed, Embase, Cochrane Central Register of Controlled Trials, Chinese Biomedical Literature Database, China National Knowledge Infrastructure, Wanfang database dating from January 2007 to January 2017. The curative effects of probiotics on the reduction of TC were assessed using mean difference (MD), as well as their 95% confidence interval (CI). RevMan software (version 5.3) was used to carry out this meta-analysis. Thirty-two RCTs including 1971 patients met the inclusion criteria. Results of this analysis showed that compared with the control group serum TC was significantly reduced in probiotics group [MD = -13.27, 95% CI (-16.74 to 9.80), P  6 weeks: [MD = -22.18, 95% CI (-28.73, -15.63), P probiotics forms and intervention duration might have a significant impact on the results. However, strains and doses of probiotics had no significant influence on curative effects. Available evidence indicates that probiotics supplements can significantly reduce serum TC. Furthermore, higher baseline TC, longer intervention time, and probiotics in capsules form might contribute to a better curative effect.

Simulation Research on Adaptive Control of a Six-degree-of-freedom Material-testing Machine

Directory of Open Access Journals (Sweden)

Dan Wang

2014-02-01

Full Text Available This paper presents an adaptive controller equipped with a stiffness estimation method for a novel material-testing machine, in order to alleviate the performance depression caused by the stiffness variance of the tested specimen. The dynamic model of the proposed machine is built using the Kane method, and kinematic model is established with a closed-form solution. The stiffness estimation method is developed based on the recursive least-squares method and the proposed stiffness equivalent matrix. Control performances of the adaptive controller are simulated in detail. The simulation results illustrate that the proposed controller can greatly improve the control performance of the target material-testing machine by online stiffness estimation and adaptive parameter tuning, especially in low-cycle fatigue (LCF and high-cycle fatigue (HCF tests.

Theory of strain-controlled magnetotransport and stabilization of the ferromagnetic insulating phase in manganite thin films.

Science.gov (United States)

Mukherjee, Anamitra; Cole, William S; Woodward, Patrick; Randeria, Mohit; Trivedi, Nandini

2013-04-12

We show that applying strain on half-doped manganites makes it possible to tune the system to the proximity of a metal-insulator transition and thereby generate a colossal magnetoresistance (CMR) response. This phase competition not only allows control of CMR in ferromagnetic metallic manganites but can be used to generate CMR response in otherwise robust insulators at half-doping. Further, from our realistic microscopic model of strain and magnetotransport calculations within the Kubo formalism, we demonstrate a striking result of strain engineering that, under tensile strain, a ferromagnetic charge-ordered insulator, previously inaccessible to experiments, becomes stable.

Novel Strategies Using Total Gastrodin and Gastrodigenin, or Total Gastrodigenin for Quality Control of Gastrodia elata.

Science.gov (United States)

Tang, Chunlan; Wu, Bingchu; Wu, Jinyi; Zhang, Zheng; Yu, Bocheng

2018-01-29

Gastrodia elata Blume ( G. elata ), a traditional Chinese medicine, is widely used for treatment of various neuro dysfunctions. However, its quality control is still limited to the determination of gastrodin. In the present study, two novel strategies based on quantitative evaluation of total gastrodin and gastrodigenin with base hydrolysis and total gastrodigenin with base-enzymatic hydrolysis followed by HPLC-FLD were put forward and successfully applied to evaluate the quality of 47 batches of G. elata from eight localities. Meanwhile, a systematic comparison of the novel strategy with the multiple markers and the Pharmacopeia method was performed. The results showed that the parishins category could be completely hydrolyzed to gastrodin by sodium hydroxide solution, and gastrodin could further utterly hydrolyze to gastrodigenin with β-d-glucosidase buffer solution. The contents of total gastrodin and gastrodigenin ranged from 1.311% to 2.034%, and total gastrodigenin from 0.748% to 1.120% at the eight localities. From the comparison, we can conclude that the two novel strategies can comprehensively reveal the characteristics of overall active ingredients in G. elata for quality control. The present study provides a feasible and credible strategy for the quality control of G. elata , suggesting a revision of the latest Chinese Pharmacopoeia or European Pharmacopoeia methods for the modernization of G. elata use.

Effectiveness of Active Packaging on Control of Escherichia Coli O157:H7 and Total Aerobic Bacteria on Iceberg Lettuce.

Science.gov (United States)

Lu, Haixia; Zhu, Junli; Li, Jianrong; Chen, Jinru

2015-06-01

Contaminated leafy green vegetables have been linked to several outbreaks of human gastrointestinal infections. Antimicrobial interventions that are adoptable by the fresh produce industry for control of pathogen contamination are in great demand. This study was undertaken to evaluate the efficacy of sustained active packaging on control of Escherichia coli O157:H7 and total aerobic bacteria on lettuce. Commercial Iceberg lettuce was inoculated with a 3-strain mixture of E. coli O157:H7 at 10(2) or 10(4) CFU/g. The contaminated lettuce and un-inoculated controls were placed respectively in 5 different active packaging structures. Traditional, nonactive packaging structure was included as controls. Packaged lettuce was stored at 4, 10, or 22 °C for 3 wk and sampled weekly for the population of E. coli O157:H7 and total aerobic bacteria. Results showed that packaging structures with ClO2 generator, CO2 generator, or one of the O2 scavengers effectively controlled the growth of E. coli O157:H7 and total aerobic bacteria under all storage conditions. Packaging structure with the ClO2 generator was most effective and no E. coli O157:H7 was detected in samples packaged in this structure except for those that were inoculated with 4 log CFU/g of E. coli O157:H7 and stored at 22 °C. Packaging structures with an oxygen scavenger and the allyl isothiocyanate generator were mostly ineffective in control of the growth of the bacteria on Iceberg lettuce. The research suggests that some of the packaging structures evaluated in the study can be used to control the presence of foodborne pathogens on leafy green vegetables. © 2015 Institute of Food Technologists®

Effect of strain on voltage-controlled magnetism in BiFeO₃-based heterostructures.

Science.gov (United States)

Wang, J J; Hu, J M; Yang, T N; Feng, M; Zhang, J X; Chen, L Q; Nan, C W

2014-04-01

Voltage-modulated magnetism in magnetic/BiFeO3 heterostructures can be driven by a combination of the intrinsic ferroelectric-antiferromagnetic coupling in BiFeO3 and the antiferromagnetic-ferromagnetic exchange interaction across the heterointerface. However, ferroelectric BiFeO3 film is also ferroelastic, thus it is possible to generate voltage-induced strain in BiFeO3 that could be applied onto the magnetic layer across the heterointerface and modulate magnetism through magnetoelastic coupling. Here, we investigated, using phase-field simulations, the role of strain in voltage-controlled magnetism for these BiFeO3-based heterostructures. It is predicted, under certain condition, coexistence of strain and exchange interaction will result in a pure voltage-driven 180° magnetization reversal in BiFeO3-based heterostructures.

Quality control of dosimetry in total body irradiation

International Nuclear Information System (INIS)

Kallinger, W.

1986-11-01

An on-line dose measurement system for the quality control of the treatment of leukemia by means of total body irradiation with Co-60 gamma radiation is introduced. An ionization chamber and 5 diodes arranged on the surface of the patient incorporated with a microprocessor provides useful information and data necessary for the treatment. Following the concerted treatment procedure employing this system, the treatment of leukemia by means of total body irradiation is expected to be improved

Effective Coping With Supervisor Conflict Depends on Control: Implications for Work Strains.

Science.gov (United States)

Eatough, Erin M; Chang, Chu-Hsiang

2018-01-11

This study examined the interactive effects of interpersonal conflict at work, coping strategy, and perceived control specific to the conflict on employee work strain using multisource and time-lagged data across two samples. In Sample 1, multisource data was collected from 438 employees as well as data from participant-identified secondary sources (e.g., significant others, best friends). In Sample 2, time-lagged data from 100 full-time employees was collected in a constructive replication. Overall, findings suggested that the success of coping efforts as indicated by lower strains hinges on the combination of the severity of the stressor, perceived control over the stressor, and coping strategy used (problem-focused vs. emotion-focused coping). Results from the current study provide insights for why previous efforts to document the moderating effects of coping have been inconsistent, especially with regards to emotion-focused coping. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Microstructure, vertical strain control and tunable functionalities in self-assembled, vertically aligned nanocomposite thin films

International Nuclear Information System (INIS)

Chen, Aiping; Bi, Zhenxing; Jia, Quanxi; MacManus-Driscoll, Judith L.; Wang, Haiyan

2013-01-01

Vertically aligned nanocomposite (VAN) oxide thin films have recently stimulated a significant amount of research interest owing to their novel architecture, vertical interfacial strain control and tunable material functionalities. In this work, the growth mechanisms of VAN thin films have been investigated by varying the composite material system, the ratio of the two constituent phases, and the thin film growth conditions including deposition temperature and oxygen pressure as well as growth rate. It has been shown that thermodynamic parameters, elastic and interfacial energies and the multiple phase ratio play dominant roles in the resulting microstructure. In addition, vertical interfacial strain has been observed in BiFeO 3 (BFO)- and La 0.7 Sr 0.3 MnO 3 (LSMO)-based VAN thin film systems; the vertical strain could be tuned by the growth parameters and selection of a suitable secondary phase. The tunability of physical properties such as dielectric loss in BFO:Sm 2 O 3 VAN and low-field magnetoresistance in LSMO-based VAN systems has been demonstrated. The enhancement and tunability of those physical properties have been attributed to the unique VAN architecture and vertical strain control. These results suggest that VAN architecture with novel microstructure and unique vertical strain tuning could provide a general route for tailoring and manipulating the functionalities of oxide thin films

Self-organized strain engineering on GaAs (311)B : template formation for quantum dot nucleation control

NARCIS (Netherlands)

Gong, Q.; Nötzel, R.; Hamhuis, G.J.; Eijkemans, T.J.; Wolter, J.H.

2002-01-01

A matrix of closely packed cells develops during molecular-beam epitaxy of In/sub 0.35/Ga/sub 0.65/As on GaAs (311)B, due to strain-driven growth instability. The established lateral strain distribution generates a unique template that controls the nucleation and growth of InAs quantum dots (QDs).

Normal references of right ventricular strain values by two-dimensional strain echocardiography according to the age and gender.

Science.gov (United States)

Park, Jae-Hyeong; Choi, Jin-Oh; Park, Seung Woo; Cho, Goo-Yeong; Oh, Jin Kyung; Lee, Jae-Hwan; Seong, In-Whan

2018-02-01

Right ventricular (RV) strain values by 2-dimensional strain echocardiography (STE) can be used as objective markers of RV systolic function. However, there is little data about normal reference RV strain values according to age and gender. We measured normal RV strain values by STE. RV strain values were analyzed from the digitally stored echocardiographic images from NORMAL (Normal echOcardiogRaphic diMensions and functions in KoreAn popuLation) study for the measurement of normal echocardiographic values performed in 23 Korean university hospitals. We enrolled total 1003 healthy persons in the NORMAL study. Of them, we analyzed 2-dimensional RV strain values in 493 subjects (261 females, mean 47 ± 15 years old) only with echocardiographic images by GE machines. Their LV systolic and diastolic functions were normal. RV fractional area change was 48 ± 6% and tricuspid annular plane systolic excursion was 23 ± 3 mm. Total RV global longitudinal peak systolic strain (RVGLS total ) was -21.5 ± 3.2%. Females had higher absolute RVGLS total (-22.3 ± 3.3 vs -20.7 ± 2.9%, p value to that of older males (age ≥50 years, -20.5 ± 2.8 vs -20.9 ± 3.1%, p = 0.224). We calculated normal RVGLS values in normal population. Females have higher absolute strain values than males, especially in younger age groups (<50 years old).

Association Between Maternal Serum Total Oxidant Status Total Antioxidant Status and Preterm Labor: A Prospective - Controlled Clinical Study

OpenAIRE

Hakan Kalaycı; Mete Gürol Uğur; Ebru Öztürk; Özcan Balat; Özcan Erel

2011-01-01

OBJECTIVE: To measure the levels of individual antioxidant components of pregnants with preterm labor to evaluate their total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI). STUDY DESIGN: Prospectively-controlled 31 pregnants with a diagnosis of preterm labor (group Ι) and 32 controls (group ΙΙ) were evaluated for demographic data, general and obstetrical physical examination, obstetrical sonography, and routine laboratory tests. TAS, TOS and OSI leve...

Proximal forearm extensor muscle strain is reduced when driving nails using a shock-controlled hammer.

Science.gov (United States)

Buchanan, Kimberly A; Maza, Maria; Pérez-Vázquez, Carlos E; Yen, Thomas Y; Kijowski, Richard; Liu, Fang; Radwin, Robert G

2016-10-01

Repetitive hammer use has been associated with strain and musculoskeletal injuries. This study investigated if using a shock-control hammer reduces forearm muscle strain by observing adverse physiological responses (i.e. inflammation and localized edema) after use. Three matched framing hammers were studied, including a wood-handle, steel-handle, and shock-control hammer. Fifty volunteers were randomly assigned to use one of these hammers at a fatiguing pace of one strike every second, to seat 20 nails in a wood beam. Magnetic resonance imaging was used to scan the forearm muscles for inflammation before the task, immediately after hammering, and one to two days after. Electromyogram signals were measured to estimate grip exertions and localized muscle fatigue. High-speed video was used to calculate the energy of nail strikes. While estimated grip force was similar across the three hammers, the shock-control hammer had 40% greater kinetic energy upon impact and markedly less proximal extensor muscle edema than the wood-handle and steel-handle hammers, immediately after use (phandle shock can mitigate strain in proximal forearm extensor muscles. Copyright © 2016 Elsevier Ltd. All rights reserved.

Hydrostatic-pressure and uniaxial-strain experiments for controlling the spin-Peierls transition

International Nuclear Information System (INIS)

Mito, Masaki; Deguchi, Hiroyuki; Fujita, Wataru; Kondo, Ryusuke; Kagoshima, Seiichi

2010-01-01

The spin-Peierls (SP) system is considered to be a quantum spin system strongly coupled with the lattice. We have succeeded in controlling SP transition by applying hydrostatic pressure and/or uniaxial strain. The observed phenomenon could be a typical example for understanding the SP transition based on the Hamiltonian. (author)

Family food purchases of high- and low-calorie foods in full-service supermarkets and other food retailers by Black women in an urban US setting.

Science.gov (United States)

Chrisinger, Benjamin W; DiSantis, Katherine Isselmann; Hillier, Amy E; Kumanyika, Shiriki K

2018-06-01

Public health interventions to increase supermarket access assume that shopping in supermarkets is associated with healthier food purchases compared to other store types. To test this assumption, we compared purchasing patterns by store-type for certain higher-calorie, less healthy foods (HCF) and lower-calorie, healthier foods (LCF) in a sample of 35 black women household shoppers in Philadelphia, PA. Data analyzed were from 450 food shopping receipts collected by these shoppers over four-week periods in 2012. We compared the likelihood of purchasing the HCF (sugar-sweetened beverages, sweet/salty snacks, and grain-based snacks) and LCF (low-fat dairy, fruits, and vegetables) at full-service supermarkets and six other types of food retailers, using generalized estimating equations. Thirty-seven percent of participants had household incomes at or below the poverty line, and 54% had a BMI >30. Participants shopped primarily at full-service supermarkets (55%) or discount/limited assortment supermarkets (22%), making an average of 11 shopping trips over a 4-week period and spending mean (SD) of $350 ($222). Of full-service supermarket receipts, 64% included at least one HCF item and 58% at least one LCF. Most trips including HCF (58%) and LCF (60%) expenditures were to full-service or discount/limited assortment supermarkets rather than smaller stores. Spending a greater percent of total dollars in full-service supermarkets was associated with spending more on HCF (p = 0.03) but not LCF items (p = 0.26). These findings in black women suggest a need for more attention to supermarket interventions that change retailing practices and/or consumer shopping behaviors related to foods in the HCF categories examined.

A Total Quality-Control Plan with Right-Sized Statistical Quality-Control.

Science.gov (United States)

Westgard, James O

2017-03-01

A new Clinical Laboratory Improvement Amendments option for risk-based quality-control (QC) plans became effective in January, 2016. Called an Individualized QC Plan, this option requires the laboratory to perform a risk assessment, develop a QC plan, and implement a QC program to monitor ongoing performance of the QC plan. Difficulties in performing a risk assessment may limit validity of an Individualized QC Plan. A better alternative is to develop a Total QC Plan including a right-sized statistical QC procedure to detect medically important errors. Westgard Sigma Rules provides a simple way to select the right control rules and the right number of control measurements. Copyright © 2016 Elsevier Inc. All rights reserved.

Investigation of thermal fatigue behavior of thermal barrier coating systems

International Nuclear Information System (INIS)

Zhu Dongming; Miller, R.A.

1997-01-01

In the present study, the mechanisms of fatigue crack initiation and propagation, and of coating failure under thermal loads that simulate those in diesel engines are investigated. Surface cracks initiate early and grow continuously under thermal low cycle fatigue (LCF) and high cycle fatigue (HCF) stresses. It is found that, in the absence of interfacial oxidation, the failure associated with LCF is closely related to coating sintering and creep at high temperatures. Significant LCF and HCF interactions have been observed in the thermal fatigue tests. The fatigue crack growth rate in the ceramic coating strongly depends on the characteristic HCF cycle number, N* HCF which is defined as the number of HCF cycles per LCF cycle. The crack growth rate is increased from 0.36 μm/LCF cycle for a pure LCF test to 2.8 μm/LCF cycle for a combined LCF and HCF test at N* HCF about 20 000. A surface wedging model has been proposed to account for the HCF crack growth in the coating systems. This mechanism predicts that the HCF damage effect increases with heat flux and thus with increasing surface temperature swing, thermal expansion coefficient and elastic modulus of the ceramic coating, as well as with the HCF interacting depth. Good correlation has been found between the analysis and experimental evidence. (orig.)

Strain-Modulated Epitaxy

National Research Council Canada - National Science Library

Brown, April

1999-01-01

Strain-Modulated Epitaxy (SME) is a novel approach, invented at Georgia Tech, to utilize subsurface stressors to control strain and therefore material properties and growth kinetics in the material above the stressors...

Job strain and informal caregiving as predictors of long-term sickness absence

DEFF Research Database (Denmark)

Mortensen, Jesper; Dich, Nadya; Lange, Theis

2017-01-01

OBJECTIVES: The aim of this study was to investigate the individual, joint and interactive effects of job strain and informal caregiving on long-term sickness absence with special attention to gender differences. METHODS: The study comprised a prospective cohort study of 6798 working adults from...... France, 14 727 from Finland, and 5275 from the UK. A total of 26 800 participants, age 52 (interquartile range 47-56) years participated in the study. Job strain was assessed using the demand-control model. Informal caregiving was defined as care for a sick, disabled, or elderly person. Long......-term sickness absence spells defined as absence >14 consecutive days were registered during two years follow-up. We used recurrent-events Cox regression in random-effects meta-analyses. RESULTS: A total of 12% men and 21% women had ≥1 long-term sickness absence spell. Among women, both high job strain [hazard...

Effect of physical exercise on work ability and daily strain in symptomatic menopausal women: a randomized controlled trial.

Science.gov (United States)

Rutanen, Reetta; Nygård, Clas-Håkan; Moilanen, Jaana; Mikkola, Tomi; Raitanen, Jani; Tomas, Eija; Luoto, Riitta

2014-01-01

Menopause related symptoms modify quality of life and may also have an impact on work ability. The aim of this study was to investigate the effects of physical exercise on work ability and daily strain among women with menopausal symptoms. Occupationally active symptomatic menopausal women (n=123) were randomized into 24-week aerobic exercise intervention and control groups. Mobile phone questionnaires were used to collect daily data on perceived physical and mental strain in a randomised and controlled setting. Work ability was measured with the Work Ability Index (WAI) and with questions about work strain. In all 123 women aged 44-62 (mean age 53.8 ± 3.4) years who worked full- or part-time participated in the study. Women were randomized into a control (n=60) and intervention group (n=63). The subjects were mostly working in mentally demanding jobs (e.g., office worker), but also in physical (e.g., cleaner) and mixed (physical and mental) jobs (e.g., nurse). The increase in mental resources and decrease in physical strain from baseline to end were statistically significantly greater among the intervention group than among the control group. Between-group differences in the change in WAI were, however, statistically non-significant. A 6-month physical exercise intervention among symptomatic menopausal women seems not to be enough to increase perceived work ability but the physical exercise may increase perceived mental resources and decrease perceived daily physical strain.}

Efeitos de área e de borda sobre a estrutura florestal em fragmentos de floresta de terra-firme após 13-17 anos de isolamento Area and edge effects on forest structure in Amazonian forest fragments after 13-17 years of isolation

Directory of Open Access Journals (Sweden)

Henrique E. M. Nascimento

2006-01-01

Full Text Available As estimativas de densidade e biomassa de árvores vivas com DAP > 10 cm e arvoretas 1-9,9 cm de DAP, liteira lenhosa grossa caída (LCG diâmetro > 10 cm, árvores mortas em pé (> 10 de DAP e liteira lenhosa fina caída (LCF - 2,5 9,9 cm de diâmetro foram quantificadas em 56 parcelas permanentes de 1 ha, distribuídas em quatro categorias de tamanho de fragmento - fragmentos de 1 ha (4 parcelas, fragmentos de 10 ha (12 parcelas e fragmentos de 100 ha (14 parcelas e floresta contínua (19 parcelas e em duas classes de distância da borda - 300 m (21 parcelas. A densidade e a biomassa de árvores e arvoretas de espécies de estágios sucessionais mais avançados não diferiram significativamente entre as diferentes categorias de tamanho e entre as duas distâncias da borda. Por outro lado, fragmentos florestais e locais 300 m da borda, respectivamente. Fragmentos florestais apresentaram maior quantidade de LCG e LCF do que a floresta contínua. Houve também diferenças significativas entre ambas as distâncias da borda para a quantidade de LCG e LCF e necromassa total. Uma análise de covariância mostrou que não houve efeito de tamanho do fragmento, mas a distância da borda teve um efeito significativo sobre a quantidade de LCG e LCF. A quantidade de LCG e LCF foi correlacionada negativamente com a distância da borda - locais mais próximos à borda tiveram cerca de 40% e 60% mais LCG do que locais mais distantes.Density and biomass of live trees >10 cm DBH and saplings 1-9.9 cm DBH, coarse woody debris (LCG diameter > 10 cm, fine woody debris (LCF diameter 2.5-9.9 cm, and standing dead trees (> 10 cm DBH were quantified in 56 permanent, 1-ha sample plots. These plots are located in four 1- (4 plots, three 10- (12 plots and two 100- (14 plots forest fragments in size and nearby continuous forests (19 plots as well as in two classes of distance from the edges - 300 m (21 plots. Density and biomass of primary species did not differ

A real-time PCR method for quantification of the total and major variant strains of the deformed wing virus.

Directory of Open Access Journals (Sweden)

Emma L Bradford

Full Text Available European honey bees (Apis mellifera are critically important to global food production by virtue of their pollination services but are severely threatened by deformed wing virus (DWV especially in the presence of the external parasite Varroa destructor. DWV exists as many viral strains with the two major variants (DWV-A and DWV-B varying in virulence. A single plasmid standard was constructed containing three sections for the specific determination of DWV-A (VP2 capsid region, DWV-B (IRES and a conserved region suitable for total DWV (helicase region. The assays were confirmed as specific and discriminatory with limits of detections of 25, 25 and 50 genome equivalents for DWV-A, DWV-B and total-DWV, respectively. The methods were successfully tested on Apis mellifera and V. destructor samples with varying DWV profiles. The new method determined a more accurate total DWV titre in samples with substantial DWV-B than the method currently described in the COLOSS Beebook. The proposed assays could be utilized for the screening of large quantities of bee material for both a total DWV load overview along with more detailed investigations into DWV-A and DWV-B profiles.

Inaccuracy of a physical strain trainer for the monitoring of partial weight bearing.

Science.gov (United States)

Pauser, Johannes; Jendrissek, Andreas; Swoboda, Bernd; Gelse, Kolja; Carl, Hans-Dieter

2011-11-01

To investigate the use of a physical strain trainer for the monitoring of partial weight bearing. Case series with healthy volunteers. Orthopedic clinic. Healthy volunteers (N=10) with no history of foot complaints. Volunteers were taught to limit weight bearing to 10% body weight (BW) and 50% BW, monitored by a physical strain trainer. The parameters peak pressure, maximum force, force-time integral, and pressure-time integral were assessed by dynamic pedobarography when volunteers walked with full BW (condition 1), 50% BW (condition 2), and 10% BW (condition 3). With 10% BW (condition 3), forces with normative gait (condition 1) were statistically significantly reduced under the hindfoot where the physical strain trainer is placed. All pedobarographic parameters were, however, exceeded when the total foot was measured. A limitation to 10% BW with the physical strain trainer (condition 3) was equal to a bisection of peak pressure and maximum force for the total foot with normative gait (condition 1). Halved BW (condition 2) left a remaining mean 82% of peak pressure and mean 59% of maximum force from full BW (condition 1). The concept of controlling partial weight bearing with the hindfoot-addressing device does not represent complete foot loading. Such devices may be preferably applied in cases when the hindfoot in particular must be off-loaded. Other training devices (eg, biofeedback soles) that monitor forces of the total foot have to be used to control partial weight bearing of the lower limb accurately. Copyright © 2011 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Effect of strain on voltage-controlled magnetism in BiFeO3-based heterostructures

Science.gov (United States)

Wang, J. J.; Hu, J. M.; Yang, T. N.; Feng, M.; Zhang, J. X.; Chen, L. Q.; Nan, C. W.

2014-01-01

Voltage-modulated magnetism in magnetic/BiFeO3 heterostructures can be driven by a combination of the intrinsic ferroelectric-antiferromagnetic coupling in BiFeO3 and the antiferromagnetic-ferromagnetic exchange interaction across the heterointerface. However, ferroelectric BiFeO3 film is also ferroelastic, thus it is possible to generate voltage-induced strain in BiFeO3 that could be applied onto the magnetic layer across the heterointerface and modulate magnetism through magnetoelastic coupling. Here, we investigated, using phase-field simulations, the role of strain in voltage-controlled magnetism for these BiFeO3-based heterostructures. It is predicted, under certain condition, coexistence of strain and exchange interaction will result in a pure voltage-driven 180° magnetization reversal in BiFeO3-based heterostructures. PMID:24686503

Sequence analysis of measles virus strains collected during the pre- and early-vaccination era in Denmark reveals a considerable diversity of ancient strains

DEFF Research Database (Denmark)

Christensen, Laurids Siig; Schöller, S.; Schierup, M. H.

2002-01-01

A total of 199 serum samples from patients with measles collected in Denmark, Greenland and the Faroe Islands from 1964 to 1983 were analysed by PCR. Measles virus (MV) RNA could be detected in 38 (19%) of the samples and a total of 18 strains were subjected to partial sequence analysis of the he......A total of 199 serum samples from patients with measles collected in Denmark, Greenland and the Faroe Islands from 1964 to 1983 were analysed by PCR. Measles virus (MV) RNA could be detected in 38 (19%) of the samples and a total of 18 strains were subjected to partial sequence analysis...... of the hemagglutinin gene. The strains exhibited a considerable genomic diversity, which is at odds with the assumption that one genome type prevailed among globally circulating MV strains prior to the advent of live-attenuated vaccines. Our data indicate that the similarity of the various vaccine strains...... is attributed to their having originated from the same primary isolate. Consequently, it is implied that a small number of clinical manifestations of MV worldwide from which strains similar to the vaccine strain were identified were vaccine related rather than being caused by members of a persistently...

Control of Listeria monocytogenes in goat's milk and goat's jben by the bacteriocinogenic Enterococcus faecium F58 strain.

Science.gov (United States)

Achemchem, Fouad; Abrini, Jamal; Martínez-Bueno, Manuel; Valdivia, Eva; Maqueda, Mercedes

2006-10-01

The bacteriocinogenic Enterococcus faecium F58 strain, a natural goat's jben cheese isolate, lacks decarboxylase activity involved in most biogenic amine formation. It was also sensitive to 13 antibiotics assayed and free of virulence and vancomycin resistance genes. The F58 strain reached the stationary phase after 12 h of growth in sterile goat's milk, and the production of enterocin F-58 (Ent L50) was first detected after 48 h (400 AU/ml), thereafter remaining stable up to 5 days. The effectiveness of the F58 strain in controlling Listeria monocytogenes serovar 4b in reduced fat and whole goat's milk, and in goat's jben has been examined. Coculture experiments of F58-L. monocytogenes in both types of milk demonstrated that listeriae were not eliminated, although reductions by 1 to 4 log units were found. Nevertheless, when the F58 strain was previously inoculated in whole milk and left to grow for 12 h before contamination, the pathogen was completely eliminated after 130 h of coculture. Production of jben cheese contaminated with L. monocytogenes prior to packaging, using preparations of F58-producer strain, caused a significant decrease in the number of viable listeriae, which were undetectable after 1 week of cheese storage at 22 degrees C. Altogether, results from this study suggest that E. faecium F58 strain may be used as an adjunct culture in cheese to control contamination and growth of L. monocytogenes by in situ enterocin production, thus providing an additional hurdle to enhance control of this pathogen.

Species attribution and strain typing of Oenococcus oeni (formerly Leuconostoc oenos) with restriction endonuclease fingerprints.

Science.gov (United States)

Viti, C; Giovannetti, L; Granchi, L; Ventura, S

1996-10-01

In several wines, malolactic fermentation is required to improve the organoleptic characters and to stabilize the final product. In order to establish a controlled malolactic fermentation in wine, easy identification and sensitive typing of strains of Oenococcus oeni (new name of the malolactic bacterium Leuconostoc oenos) used as starter cultures are necessary. To accomplish these tasks, several strains of Oenococcus oeni isolated from wines of the Chianti region (Italy), along with reference strains and strains of L. mesenteroides subsp. mesenteroides, L. carnosum, L. fallax, L. pseudomesenteroides, L. lactis and Weisella paramesenteroides, were studied with RFLP of ribosomal genes and ultrasensitive total DNA restriction pattern analysis performed on polyacrylamide gel. With each of four restriction endonucleases used, identical restriction profiles of ribosomal genes were obtained for all strains of O. oeni. These ribopatterns, being strongly dissimilar to profiles of the other lactic acid bacteria tested, appear to be well suited for the attribution of wine lactic acid bacteria to the species O. oeni. Cluster analysis performed on two total DNA restriction profile data sets showed that the species O. oeni possesses a good degree of genomic homogeneity. Very sensitive typing of strains of O. oeni was obtained with total DNA restriction profiles. The potential of an integrated approach using restriction profiles for species assignment and typing of selected malolactic bacteria is demonstrated.

Substrate-Limited Saccharomyces cerevisiae Yeast Strains Allow Control of Fermentation during Bread Making.

Science.gov (United States)

Struyf, Nore; Laurent, Jitka; Verspreet, Joran; Verstrepen, Kevin J; Courtin, Christophe M

2017-04-26

Identification and use of yeast strains that are unable to consume one or more otherwise fermentable substrate types could allow a more controlled fermentation process with more flexibility regarding fermentation times. In this study, Saccharomyces cerevisiae strains with different capacities to consume substrates present in wheat were selected to investigate the impact of substrate limitation on dough fermentation and final bread volume. Results show that fermentation of dough with maltose-negative strains relies on the presence of fructan and sucrose as fermentable substrates and can be used for regular bread making. Levels of fructan and sucrose, endogenously present or added, hence determine the extent of fermentation and timing at the proofing stage. Whole meal is inherently more suitable for substrate-limited fermentation than white flour due to the presence of higher native levels of these substrates. Bread making protocols with long fermentation times are accommodated by addition of substrates such as sucrose.

Validity test of the IPD-Work consortium approach for creating comparable job strain groups between Job Content Questionnaire and Demand-Control Questionnaire

Directory of Open Access Journals (Sweden)

Bongkyoo Choi

2015-04-01

Full Text Available Objectives: This study aims to test the validity of the IPD-Work Consortium approach for creating comparable job strain groups between the Job Content Questionnaire (JCQ and the Demand-Control Questionnaire (DCQ. Material and Methods: A random population sample (N = 682 of all middle-aged Malmö males and females was given a questionnaire with the 14-item JCQ and 11-item DCQ for the job control and job demands. The JCQ job control and job demands scores were calculated in 3 different ways: using the 14-item JCQ standard scale formulas (method 1; dropping 3 job control items and using the 11-item JCQ standard scale formulas with additional scale weights (method 2; and the approach of the IPD Group (method 3, dropping 3 job control items, but using the simple 11-item summation-based scale formulas. The high job strain was defined as a combination of high demands and low control. Results: Between the 2 questionnaires, false negatives for the high job strain were much greater than false positives (37–49% vs. 7–13%. When the method 3 was applied, the sensitivity of the JCQ for the high job strain against the DCQ was lowest (0.51 vs. 0.60–0.63 when the methods 1 and 2 were applied, although the specificity was highest (0.93 vs. 0.87–0.89 when the methods 1 and 2 were applied. The prevalence of the high job strain with the JCQ (the method 3 was applied was considerably lower (4–7% than with the JCQ (the methods 1 and 2 were applied and the DCQ. The number of congruent cases for the high job strain between the 2 questionnaires was smallest when the method 3 was applied. Conclusions: The IPD-Work Consortium approach showed 2 major weaknesses to be used for epidemiological studies on the high job strain and health outcomes as compared to the standard JCQ methods: the greater misclassification of the high job strain and lower prevalence of the high job strain.

Factors affecting finite strain estimation in low-grade, low-strain clastic rocks

Science.gov (United States)

Pastor-Galán, Daniel; Gutiérrez-Alonso, Gabriel; Meere, Patrick A.; Mulchrone, Kieran F.

2009-12-01

The computer strain analysis methods SAPE, MRL and DTNNM have permitted the characterization of finite strain in two different regions with contrasting geodynamic scenarios; (1) the Talas Ala Tau (Tien Shan, Kyrgyzs Republic) and (2) the Somiedo Nappe and Narcea Antiform (Cantabrian to West Asturian-Leonese Zone boundary, Variscan Belt, NW of Iberia). The performed analyses have revealed low-strain values and the regional strain trend in both studied areas. This study also investigates the relationship between lithology (grain size and percentage of matrix) and strain estimates the two methodologies used. The results show that these methods are comparable and the absence of significant finite strain lithological control in rocks deformed under low metamorphic and low-strain conditions.

Family food purchases of high- and low-calorie foods in full-service supermarkets and other food retailers by Black women in an urban US setting

Directory of Open Access Journals (Sweden)

Benjamin W. Chrisinger

2018-06-01

Full Text Available Public health interventions to increase supermarket access assume that shopping in supermarkets is associated with healthier food purchases compared to other store types. To test this assumption, we compared purchasing patterns by store-type for certain higher-calorie, less healthy foods (HCF and lower-calorie, healthier foods (LCF in a sample of 35 black women household shoppers in Philadelphia, PA. Data analyzed were from 450 food shopping receipts collected by these shoppers over four-week periods in 2012. We compared the likelihood of purchasing the HCF (sugar-sweetened beverages, sweet/salty snacks, and grain-based snacks and LCF (low-fat dairy, fruits, and vegetables at full-service supermarkets and six other types of food retailers, using generalized estimating equations. Thirty-seven percent of participants had household incomes at or below the poverty line, and 54% had a BMI >30. Participants shopped primarily at full-service supermarkets (55% or discount/limited assortment supermarkets (22%, making an average of 11 shopping trips over a 4-week period and spending mean (SD of $350 ($222. Of full-service supermarket receipts, 64% included at least one HCF item and 58% at least one LCF. Most trips including HCF (58% and LCF (60% expenditures were to full-service or discount/limited assortment supermarkets rather than smaller stores. Spending a greater percent of total dollars in full-service supermarkets was associated with spending more on HCF (p = 0.03 but not LCF items (p = 0.26. These findings in black women suggest a need for more attention to supermarket interventions that change retailing practices and/or consumer shopping behaviors related to foods in the HCF categories examined. Keywords: Obesity, Store choice, Food choice, Food shopping, Supermarkets, African Americans

Nickel speciation in several serpentine (ultramafic) topsoils via bulk synchrotron-based techniques

Energy Technology Data Exchange (ETDEWEB)

Siebecker, Matthew G.; Chaney, Rufus L.; Sparks, Donald L.

2017-07-01

Serpentine soils have elevated concentrations of trace metals including nickel, cobalt, and chromium compared to non-serpentine soils. Identifying the nickel bearing minerals allows for prediction of potential mobility of nickel. Synchrotron-based techniques can identify the solid-phase chemical forms of nickel with minimal sample treatment. Element concentrations are known to vary among soil particle sizes in serpentine soils. Sonication is a useful method to physically disperse sand, silt and clay particles in soils. Synchrotron-based techniques and sonication were employed to identify nickel species in discrete particle size fractions in several serpentine (ultramafic) topsoils to better understand solid-phase nickel geochemistry. Nickel commonly resided in primary serpentine parent material such as layered-phyllosilicate and chain-inosilicate minerals and was associated with iron oxides. In the clay fractions, nickel was associated with iron oxides and primary serpentine minerals, such as lizardite. Linear combination fitting (LCF) was used to characterize nickel species. Total metal concentration did not correlate with nickel speciation and is not an indicator of the major nickel species in the soil. Differences in soil texture were related to different nickel speciation for several particle size fractionated samples. A discussion on LCF illustrates the importance of choosing standards based not only on statistical methods such as Target Transformation but also on sample mineralogy and particle size. Results from the F-test (Hamilton test), which is an underutilized tool in the literature for LCF in soils, highlight its usefulness to determine the appropriate number of standards to for LCF. EXAFS shell fitting illustrates that destructive interference commonly found for light and heavy elements in layered double hydroxides and in phyllosilicates also can occur in inosilicate minerals, causing similar structural features and leading to false positive results in

Evaluation of the endophytic nature of Bacillus amyloliquefaciens strain GYL4 and its efficacy in the control of anthracnose.

Science.gov (United States)

Kim, Jeong Do; Jeon, Byeong Jun; Han, Jae Woo; Park, Min Young; Kang, Sin Ae; Kim, Beom Seok

2016-08-01

Endophytic bacteria are viewed as a potential new source of biofungicides because they have beneficial characteristics as control agents for plant disease. This study was performed to examine the endophytic feature and disease control efficacy of Bacillus amyloliquefaciens strain GYL4 and to identify the antifungal compounds produced by this strain. B. amyloliquefaciens strain GYL4 was isolated from leaf tissue of pepper plants (Capsicum annuum L.). Anthracnose symptoms were markedly reduced in the leaves of pepper plants colonised by GYL4. An egfp-expressing strain of GYL4 (GYL4-egfp) was constructed and reintroduced into pepper plants, which confirmed its ability to colonise the internal tissues of pepper plants. GYL4-egfp was observed in the root and stem tissues 4 days after treatment and abundantly found in the internal leaf tissue 9 days after treatment. Bacillomycin derivatives purified from the culture extract of GYL4 displayed control efficacy on anthracnose development in cucumber (Cucumis sativus L. cv. Chunsim). The present study is the first report on evaluation of the endophytic and systemic nature of B. amyloliquefaciens strain GYL4 and its potential as a biocontrol agent for anthracnose management. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites. Topical Report

Energy Technology Data Exchange (ETDEWEB)

Nguyen, Ba Nghiep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fifield, Leonard S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Jin [Autodesk, Inc., Ithaca, NY (United States); Costa, Franco [Autodesk, Inc., Ithaca, NY (United States); Lambert, Gregory [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Baird, Donald G. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Sharma, Bhisham A. [Purdue Univ., West Lafayette, IN (United States); Kijewski, Seth A. [Purdue Univ., West Lafayette, IN (United States); Sangid, Michael D. [Purdue Univ., West Lafayette, IN (United States); Gandhi, Umesh N. [Toyota Research Inst. North America, Ann Arbor, MI (United States); Wollan, Eric J. [PlastiComp, Inc., Winona, MN (United States); Roland, Dale [PlastiComp, Inc., Winona, MN (United States); Mori, Steven [Magna Exteriors and Interiors Corporation, Aurora, ON (Canada); Tucker, III, Charles L. [Univ. of Illinois, Urbana-Champaign, IL (United States)

2016-06-01

This project aimed to integrate, optimize, and validate the fiber orientation and length distribution models previously developed and implemented in the Autodesk® Simulation Moldflow® Insight (ASMI) software package for injection-molded long-carbon-fiber (LCF) thermoplastic composite structures. The project was organized into two phases. Phase 1 demonstrated the ability of the advanced ASMI package to predict fiber orientation and length distributions in LCF/polypropylene (PP) and LCF/polyamide-6, 6 (PA66) plaques within 15% of experimental results. Phase 2 validated the advanced ASMI package by predicting fiber orientation and length distributions within 15% of experimental results for a complex three-dimensional (3D) Toyota automotive part injection-molded from LCF/PP and LCF/PA66 materials. Work under Phase 2 also included estimate of weight savings and cost impacts for a vehicle system using ASMI and structural analyses of the complex part. The present report summarizes the completion of Phases 1 and 2 work activities and accomplishments achieved by the team comprising Pacific Northwest National Laboratory (PNNL); Purdue University (Purdue); Virginia Polytechnic Institute and State University (Virginia Tech); Autodesk, Inc. (Autodesk); PlastiComp, Inc. (PlastiComp); Toyota Research Institute North America (Toyota); Magna Exteriors and Interiors Corp. (Magna); and University of Illinois. Figure 1 illustrates the technical approach adopted in this project that progressed from compounding LCF/PP and LCF/PA66 materials, to process model improvement and implementation, to molding and modeling LCF/PP and LCF/PA66 plaques. The lessons learned from the plaque study and the successful validation of improved process models for fiber orientation and length distributions for these plaques enabled the project to go to Phase 2 to mold, model, and optimize the 3D complex part.

Coatings for Oxidation and Hot Corrosion Protection of Disk Alloys

Science.gov (United States)

Nesbitt, Jim; Gabb, Tim; Draper, Sue; Miller, Bob; Locci, Ivan; Sudbrack, Chantal

2017-01-01

Increasing temperatures in aero gas turbines is resulting in oxidation and hot corrosion attack of turbine disks. Since disks are sensitive to low cycle fatigue (LCF), any environmental attack, and especially hot corrosion pitting, can potentially seriously degrade the life of the disk. Application of metallic coatings are one means of protecting disk alloys from this environmental attack. However, simply the presence of a metallic coating, even without environmental exposure, can degrade the LCF life of a disk alloy. Therefore, coatings must be designed which are not only resistant to oxidation and corrosion attack, but must not significantly degrade the LCF life of the alloy. Three different Ni-Cr coating compositions (29, 35.5, 45wt. Cr) were applied at two thicknesses by Plasma Enhanced Magnetron Sputtering (PEMS) to two similar Ni-based disk alloys. One coating also received a thin ZrO2 overcoat. The coated samples were also given a short oxidation exposure in a low PO2 environment to encourage chromia scale formation. Without further environmental exposure, the LCF life of the coated samples, evaluated at 760C, was less than that of uncoated samples. Hence, application of the coating alone degraded the LCF life of the disk alloy. Since shot peening is commonly employed to improve LCF life, the effect of shot peening the coated and uncoated surface was also evaluated. For all cases, shot peening improved the LCF life of the coated samples. Coated and uncoated samples were shot peened and given environmental exposures consisting of 500 hrs of oxidation followed by 50 hrs of hot corrosion, both at 760C). The high-Cr coating showed the best LCF life after the environmental exposures. Results of the LCF testing and post-test characterization of the various coatings will be presented and future research directions discussed.

Quality-control ranges for antimicrobial susceptibility testing by broth dilution of the Brachyspira hyodysenteriae type strain (ATCC 27164(T))

DEFF Research Database (Denmark)

Pringle, M.; Aarestrup, Frank Møller; Bergsjø, B.

2006-01-01

There are no approved standards for antimicrobial susceptibility testing of the fastidious spirochete Brachyspira hyodysenteriae. An interlaboratory study was performed to establish MIC quality control ranges for six antimicrobial agents for the type strain of B. hyodysenteriae using broth diluti....... The results showed that B. hyodysenteriae B78(T) ATCC 27164(T) is a suitable quality control strain. This is a first step toward standardization of methods regarding this anaerobe....

Construction of a recombinant Bacillus velezensis strain as an integrated control agent against plant diseases and insect pests.

Science.gov (United States)

Roh, Jong Yul; Liu, Qin; Choi, Jae Young; Wang, Yong; Shim, Hee Jin; Xu, Hong Guang; Choi, Gyung Ja; Kim, Jin-Cheol; Je, Yeon Ho

2009-10-01

To construct a new recombinant strain of Bacillus velezensis that has antifungal and insecticidal activity via the expression of the insecticidal Bacillus thuringiensis crystal protein, a B. thuringiensis expression vector (pHT1K-1Ac) was generated that contained the B. thuringiensis cry1Ac gene under the control of its endogenous promoter in a minimal E. coli-B. thuringiensis shuttle vector (pHT1K). This vector was introduced into a B. velezensis isolate that showed high antifungal activities against several plant diseases, including rice blast (Magnaporthe grisea), rice sheath blight (Rhizotonia solani), tomato gray mold (Botrytis cinerea), tomato late blight (Phytophthora infestans), and wheat leaf rust (Puccinia recondita), by electroporation. The recombinant B. velezensis strain was confirmed by PCR using cry1Ac-specific primers. Additionally, the recombinant strain produced a protein approximately 130 kDa in size and parasporal inclusion bodies similar to B. thuringiensis. The in vivo antifungal activity assay demonstrated that the activity of the recombinant B. velezensis strain was maintained at the same level as that of wild-type B. velezensis. Furthermore, it exhibited high insecticidal activity against a lepidopteran pest, Plutella xylostella, although its activity was lower than that of a recombinant B. thuringiensis strain, whereas wild-type B. velezensis strain did not show any insecticidal activity. These results suggest that this recombinant B. velezensis strain can be used to control harmful insect pests and fungal diseases simultaneously in one crop.

Job strain among rubber-glove-factory workers in central Thailand.

Science.gov (United States)

Sein, Muang Muang; Howteerakul, Nopporn; Suwannapong, Nawarat; Jirachewee, Jirachai

2010-01-01

Job strain has become a major concern because of its potential impacts on worker well-being and performance. This cross-sectional study aimed to assess the prevalence of, and examine factors associated with, job strain among workers in a rubber-glove factory, in a central province of Thailand. A total of 200 workers aged 18-55 yr, who had worked at the factory for at least 6 months, completed the Job Content Questionnaire (JCQ) (Thai Version). Two of 5 scales in the JCQ were used to measure job strain, i.e.; job control and psychological job demand. The prevalence of job strain was 27.5%. Multiple logistic regression analysis indicated two variables significantly associated with job strain: low supervisor social support (adjusted OR=3.08; 95%CI: 1.38-6.91) and high job insecurity (adjusted OR=2.25; 95%CI: 1.04-4.88). Effective training for supervisors, to create good relationships among workers and supervisors, and ensuring steady and secure jobs for good employees, are necessary.

Microgrid Stability Controller Based on Adaptive Robust Total SMC

OpenAIRE

Su, Xiaoling; Han, Minxiao; Guerrero, Josep M.; Sun, Hai

2015-01-01

This paper presents a microgrid stability controller (MSC) in order to provide existing distributed generation units (DGs) the additional functionality of working in islanding mode without changing their control strategies in grid-connected mode and to enhance the stability of the microgrid. Microgrid operating characteristics and mathematical models of the MSC indicate that the system is inherently nonlinear and time-variable. Therefore, this paper proposes an adaptive robust total sliding...

Job strain and male fertility.

Science.gov (United States)

Hjollund, Niels Henrik I; Bonde, Jens Peter E; Henriksen, Tine Brink; Giwercman, Aleksander; Olsen, Jørn

2004-01-01

Job strain, defined as high job demands and low job control, has not previously been explored as a possible determinant of male fertility. We collected prospective data on job strain among men, and describe the associations with semen quality and probability of conceiving a clinical pregnancy during a menstrual cycle. Danish couples (N = 399) who were trying to become pregnant for the first time were followed for up to 6 menstrual periods. All men collected semen samples, and a blood sample was drawn from both partners. Job demand and job control were measured by a self-administered questionnaire at entry, and in each cycle the participants recorded changes in job control or job demand during the previous 30 days. In adjusted analyses, no associations were found between any semen characteristic or sexual hormones and any job strain variable. The odds for pregnancy were not associated with job strain. Psychologic job strain encountered in normal jobs in Denmark does not seem to affect male reproductive function.

The LCF behaviour of SS AISI 304 in the temperature range between 450 deg. C and 850 deg. C in connection with life time predictions

International Nuclear Information System (INIS)

Bocek, M.; Petersen, C.; Schmitt, R.

The lifetime in high amplitude strain cycling with tensional hold periods is analysed presuming that creep failure damage is life determining. The life fraction rule (LFR) is used to calculate the lifetime consumpted during the dwell period in strain controlled tests as well as during tensional hold time stress cycles. It follows from the present investigation that stress relaxation occurring during the strain hold periods has a dominant influence upon the lifetime. The damage in stress relaxation is calculated by means of the LFR and the results are compared to experiments conducted on Zircaloy-4 (T=600 deg. C) and the austenitic stainless steel Type AISI 304 (T=650 deg. C). From the very good agreement between both it is concluded that under the loading conditions considered, creep failure damage is the main life determining damage contribution. To investigate the contributions of creep and fatigue to failure damage stress controlled experiments were conducted on AISI 304 at 550 deg. C and 850 deg. C. Whereas at the lower temperature (T 0.6 Tsub(s)) the lifetime increased with decreasing R. Therefrom it is concluded that in the case considered for T>0.6 Tsub(s) fatigue damage is not lifetime determining. (author)

A strain-controlled C2N monolayer membrane for gas separation in PEMFC application

Science.gov (United States)

Deng, Shengwei; Hu, Hui; Zhuang, Guilin; Zhong, Xing; Wang, Jianguo

2018-05-01

Ultrathin membranes with controllable pore sizes have great potential to realize high-selectivity gas separation at low energy cost, especially for those mixtures with narrow size distributions. Using a combination of van der Waals-corrected density functional theory (DFT) calculations and molecular dynamics (MD) simulation, we examine the separation ability of biaxial stretched monolayer C2N nanosheets which is applied to the O2 separation from CO/CO2/O2 mixtures in the cathode of proton exchange membrane fuel cells (PEMFC). The DFT calculations show that the diffusion energy barrier for molecules passing through the membrane followed by CO, CO2 and O2 in descending order, and an overall decrease of energy barriers due to the widen the pore size is observed with the increase of applied strains. Furthermore, MD results show that the nanosheet can effectively purify O2 from CO2 and CO with a strain from 8% to 10%. It confirms that the selectivity is determined by the electronic structure related interaction in addition to the kinetic diameter of individual molecules. The O2 permeability is improved progressively with further increase of strain, and small amount of CO2 begins to permeate through the nanosheet at relatively large strain, while the excellent CO isolation is not compromised until the theoretical maximum strain.

Comparative developmental trajectory of four strains of chicken ...

African Journals Online (AJOL)

This study evaluated egg traits, embryonic growth, and early growth rate in four strains of chicken. A total of 1200 hatching eggs, 300 each from four strains of chicken were used for this study. The strains included Nigerian indigenous chicken (NIC), Arbor acre, Hubbard, and Marshall broiler strains. Embryonic weights, yolk ...

Sandstone compaction under actively controlled uniaxial strain conditions - an experimental study on the causes of subsidence in the Dutch Wadden Area

Science.gov (United States)

Hol, Sander; Mossop, Antony; van der Linden, Arjan; Zuiderwijk, Pedro; Makurat, Axel; van Eijs, Rob

2016-04-01

In the Wadden Sea, a tidal-flat area located between the North Sea and the Dutch mainland shore, and UNESCO World Heritage site, subsidence could potentially impact the ecological system. To guide the licensing process governing gas extraction for the area by a solid understanding of the system's response to production, Nederlandse Aardolie Maatschappij (NAM) has carried out a study on the magnitudes, timing, and mechanisms of subsidence related to gas production. As part of this study program, we address the effect of production-induced reservoir compaction, using core samples from the Moddergat field located at the Wadden Sea coastline, from a depth of ~3800 m TVDSS, to assess the nature of the compaction mechanisms that operate. In this contribution, we focus on the uniaxial strain response of Permian, Aeolian sandstone to pore pressure depletion. As the majority of experiments reported in the literature are conducted under triaxial stress conditions, this data set is somewhat unique, and can help confirm the validity of micromechanical processes found for triaxial stress conditions. We report over 30 data sets of experiments carried out using 1.0 and 1.5 inch diameter plugs, sub-sampled from the extracted sandstone core material. The experiments start at in-situ conditions of pore pressure (Pf=~57 MPa), stress (Sv=~80 MPa, Sh=~67 MPa) and temperature (T up to 100 °C), and deplete to a pore pressure of 3 MPa, under actively controlled lateral constraint boundary conditions (i.e. uniaxial strain). Care was taken to systematically vary porosity and sample morphology to ensure representation of the intra-reservoir variability. Our laboratory data show that pressure-depletion results in a strain in the range of 5·10-3-1·10-2 over the total duration of the experiments of 5-12 weeks, with approximately 80% of the total strain response being close to instantaneous, and 20% developing over time. The total strain response develops during depletion as a result of

Validity test of the IPD-Work consortium approach for creating comparable job strain groups between Job Content Questionnaire and Demand-Control Questionnaire.

Science.gov (United States)

Choi, Bongkyoo; Ko, Sangbaek; Ostergren, Per-Olof

2015-01-01

This study aims to test the validity of the IPD-Work Consortium approach for creating comparable job strain groups between the Job Content Questionnaire (JCQ) and the Demand-Control Questionnaire (DCQ). A random population sample (N = 682) of all middle-aged Malmö males and females was given a questionnaire with the 14-item JCQ and 11-item DCQ for the job control and job demands. The JCQ job control and job demands scores were calculated in 3 different ways: using the 14-item JCQ standard scale formulas (method 1); dropping 3 job control items and using the 11-item JCQ standard scale formulas with additional scale weights (method 2); and the approach of the IPD Group (method 3), dropping 3 job control items, but using the simple 11-item summation-based scale formulas. The high job strain was defined as a combination of high demands and low control. Between the 2 questionnaires, false negatives for the high job strain were much greater than false positives (37-49% vs. 7-13%). When the method 3 was applied, the sensitivity of the JCQ for the high job strain against the DCQ was lowest (0.51 vs. 0.60-0.63 when the methods 1 and 2 were applied), although the specificity was highest (0.93 vs. 0.87-0.89 when the methods 1 and 2 were applied). The prevalence of the high job strain with the JCQ (the method 3 was applied) was considerably lower (4-7%) than with the JCQ (the methods 1 and 2 were applied) and the DCQ. The number of congruent cases for the high job strain between the 2 questionnaires was smallest when the method 3 was applied. The IPD-Work Consortium approach showed 2 major weaknesses to be used for epidemiological studies on the high job strain and health outcomes as compared to the standard JCQ methods: the greater misclassification of the high job strain and lower prevalence of the high job strain. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Transcriptome differences between enrofloxacin-resistant and enrofloxacin-susceptible strains of Aeromonas hydrophila

OpenAIRE

Zhu, Fengjiao; Yang, Zongying; Zhang, Yiliu; Hu, Kun; Fang, Wenhong

2017-01-01

Enrofloxacin is the most commonly used antibiotic to control diseases in aquatic animals caused by A. hydrophila. This study conducted de novo transcriptome sequencing and compared the global transcriptomes of enrofloxacin-resistant and enrofloxacin-susceptible strains. We got a total of 4,714 unigenes were assembled. Of these, 4,122 were annotated. A total of 3,280 unigenes were assigned to GO, 3,388 unigenes were classified into Cluster of Orthologous Groups of proteins (COG) using BLAST an...

Selection of Trichogramma strains and determination of number of parasitoids to be released to control Gymnandrosoma aurantianum Lima (Lepidoptera, Tortricidae)

International Nuclear Information System (INIS)

Molina, Rosa Maria da Silva; Parra, Jose Roberto Postali

2006-01-01

In order to select Trichogramma strains to control G. aurantianum, the biological characteristics of 13 Trichogramma species/strains were evaluated. After selection, the ideal number of T. pretiosum (G18 strain) to be released per G. aurantianum egg was determined in greenhouse tests. The selection test for species/strains was carried out in an incubator adjusted to 25 +- 1 deg C, RH 70 +- 10%, and a 14 h photo phase. The ideal number of parasitoids was estimated in cages covered with a piece of voile-type fabric. The cycle duration for the 13 Trichogramma species/strains varied from 10.2 to 11.9 days. The Atp strain (T. atopovirilia) showed greater parasitism capacity, with an average of 23.3 parasitized eggs and 77.5% parasitism in 24 hours. The G18 strain (T. pretiosum) came next, with an average of 16.8 parasitized eggs and 56.1% parasitism during the same time interval. The emergency, longevity of males, and sex ratio for the 13 species/strains were similar. The number of adults emerged per egg was 1.8 for strains G11 (T. pretiosum) and Br10 (T. bruni), which were different from the G3 strain (T. pretiosum) only, with 1.3 adults per egg. With regard to female longevity, distinct values were observed only between T. pretiosum strains Tp and L2, with 6.3 and 9.3 days, respectively. Under greenhouse conditions, the estimated ratio of 36 T. pretiosum parasitoids per G. aurantianum egg allowed the highest percentage of parasitism (89%). Therefore, Trichogramma spp. has a potential to control G. aurantianum, as long as a large number of parasitoids is released per unit area. (author)

Isolation strategy of a two-strain avian influenza model using optimal control

Science.gov (United States)

Mardlijah, Ariani, Tika Desi; Asfihani, Tahiyatul

2017-08-01

Avian influenza has killed many victims of both birds and humans. Most cases of avian influenza infection in humans have resulted transmission from poultry to humans. To prevent or minimize the patients of avian influenza can be done by pharmaceutical and non-pharmaceutical measures such as the use of masks, isolation, etc. We will be analyzed two strains of avian influenza models that focus on treatment of symptoms with insulation, then investigate the stability of the equilibrium point by using Routh-Hurwitz criteria. We also used optimal control to reduce the number of humans infected by making the isolation level as the control then proceeds optimal control will be simulated. The completion of optimal control used in this study is the Pontryagin Minimum Principle and for simulation we are using Runge Kutta method. The results obtained showed that the application of two control is more optimal compared to apply one control only.

The hold-time effects on the low cycle fatigue behaviors of 316 SS in PWR primary environment

International Nuclear Information System (INIS)

Lee, Junho; Hong, Jong-Dae; Seo, Myung-Gyu; Jang, Changheui

2015-01-01

The effects of the environments on fatigue life of the structural materials used in nuclear power plants (NPPs) were known to be significant according to the extensive test results. Accordingly, the fatigue analysis procedures and the design fatigue curves were proposed in the ASME Code. However, the implication that the existing ASME design fatigue curves did not sufficiently reflect the effect of the operation conditions of nuclear power plants emerged as an issue to be resolved. One of possible reasons to explain the discrepancy is that the laboratory test conditions do not represent the actual plant transients. Therefore, it is necessary to clarify the effects of light water environments on fatigue life while considering more plant-relevant transient conditions such as hold-time. For this reason, this study will focus on the fatigue life of type 316 stainless steel (SS) in the pressurized water reactor (PWR) environments while incorporating the hold-time during the low cycle fatigue (LCF) test in simulated PWR environments. The objective of this study is to characterize the effects of hold-time on the fatigue life of austenitic stainless steels in PWR environments in comparison with the existing fixed strain rate results. Low cycle fatigue life tests were conducted for the type 316 SS in 310 .deg. C air and simulated PWR environments. To simulate the heat-up and cool-down transient, sub-peak strain holding during the down-hill of strain amplitude was chosen. Currently, LCF tests with 60 seconds holding are in progress. The 0.4, 0.04%/s strain rate condition test results are presented in this study, which shows somewhat longer fatigue life

The hold-time effects on the low cycle fatigue behaviors of 316 SS in PWR primary environment

Energy Technology Data Exchange (ETDEWEB)

Lee, Junho; Hong, Jong-Dae; Seo, Myung-Gyu; Jang, Changheui [KAIST, Daejeon (Korea, Republic of)

2015-05-15

The effects of the environments on fatigue life of the structural materials used in nuclear power plants (NPPs) were known to be significant according to the extensive test results. Accordingly, the fatigue analysis procedures and the design fatigue curves were proposed in the ASME Code. However, the implication that the existing ASME design fatigue curves did not sufficiently reflect the effect of the operation conditions of nuclear power plants emerged as an issue to be resolved. One of possible reasons to explain the discrepancy is that the laboratory test conditions do not represent the actual plant transients. Therefore, it is necessary to clarify the effects of light water environments on fatigue life while considering more plant-relevant transient conditions such as hold-time. For this reason, this study will focus on the fatigue life of type 316 stainless steel (SS) in the pressurized water reactor (PWR) environments while incorporating the hold-time during the low cycle fatigue (LCF) test in simulated PWR environments. The objective of this study is to characterize the effects of hold-time on the fatigue life of austenitic stainless steels in PWR environments in comparison with the existing fixed strain rate results. Low cycle fatigue life tests were conducted for the type 316 SS in 310 .deg. C air and simulated PWR environments. To simulate the heat-up and cool-down transient, sub-peak strain holding during the down-hill of strain amplitude was chosen. Currently, LCF tests with 60 seconds holding are in progress. The 0.4, 0.04%/s strain rate condition test results are presented in this study, which shows somewhat longer fatigue life.

Development of a totally computer-controlled triple quadrupole mass spectrometer system

International Nuclear Information System (INIS)

Wong, C.M.; Crawford, R.W.; Barton, V.C.; Brand, H.R.; Neufeld, K.W.; Bowman, J.E.

1983-01-01

A totally computer-controlled triple quadrupole mass spectrometer (TQMS) is described. It has a number of unique features not available on current commercial instruments, including: complete computer control of source and all ion axial potentials; use of dual computers for data acquisition and data processing; and capability for self-adaptive control of experiments. Furthermore, it has been possible to produce this instrument at a cost significantly below that of commercial instruments. This triple quadrupole mass spectrometer has been constructed using components commercially available from several different manufacturers. The source is a standard Hewlett-Packard 5985B GC/MS source. The two quadrupole analyzers and the quadrupole CAD region contain Balzers QMA 150 rods with Balzers QMG 511 rf controllers for the analyzers and a Balzers QHS-511 controller for the CAD region. The pulsed-positive-ion-negative-ion-chemical ionization (PPINICI) detector is made by Finnigan Corporation. The mechanical and electronics design were developed at LLNL for linking these diverse elements into a functional TQMS as described. The computer design for total control of the system is unique in that two separate LSI-11/23 minicomputers and assorted I/O peripherals and interfaces from several manufacturers are used. The evolution of this design concept from totally computer-controlled instrumentation into future self-adaptive or ''expert'' systems for instrumental analysis is described. Operational characteristics of the instrument and initial results from experiments involving the analysis of the high explosive HMX (1,3,5,7-Tetranitro-1,3,5,7-Tetrazacyclooctane) are presented

Biodiversity of Lactobacillus sanfranciscensis strains isolated from five sourdoughs.

Science.gov (United States)

Kitahara, M; Sakata, S; Benno, Y

2005-01-01

Five different sourdoughs were investigated for the composition of lactic acid bacteria (LAB) and the biodiversity of Lactobacillus sanfranciscensis strains. A total of 57 strains were isolated from five sourdoughs. Isolated strains were all identified by the 16S rDNA sequence and species-specific primers for L. sanfranciscensis. Results of identification showed that LAB strains were L. sanfranciscensis, Lactobacillus plantarum, Lactobacillus paralimentarius, Lactobacillus fermentum, Lactobacillus pontis, Lactobacillus casei, Weisella confusa and Pediococcus pentosaceus. A total of 21 strains were identified as L. sanfranciscensis and these isolates were detected in all five sourdoughs. Ribotyping was applied to investigate the relationship between intraspecies diversity of L. sanfranciscensis and sourdough. A total of 22 strains of L. sanfranciscensis including L. sanfranciscensis JCM 5668T were compared by ribotyping. The dendrogram of 21 ribotyping patterns showed four clusters, and L. sanfranciscensis JCM 5668T was independent of the others. The different biotypes of L. sanfranciscensis were present in two sourdoughs compared with other three sourdoughs. The LAB compositions of five sourdoughs were different and the relationship between intraspecies diversity of L. sanfranciscensis strains and five sourdoughs was shown by ribotyping. This study demonstrated that ribotyping was useful for distinguishing L. sanfranciscensis strains. A further important result is that the intra-species diversity of L. sanfranciscensis strains seems to be related to the sourdough preparation.

IMPROVEMENT OF BORASSUS AKEASSII WINES QUALITY BY CONTROLLED FERMENTATION USING SACCHAROMYCES CEREVISIAE STRAINS

Directory of Open Access Journals (Sweden)

TAPSOBA François

2016-06-01

Full Text Available Palm wine produced traditionally and consumed by many people around the world and specifically in Burkina Faso posed health risks because of questionable quality of wine produced by mix culture fermentation and the use of antiseptics for the stabilization. In order to improve its quality, Saccharomyces cerevisiae strains isolated from Borassus akeassii wines and identified by amplification and RFLP analysis of the 5-8S-ITS region were used for in vitro fermentation of unfermented palm sap. The physicochemical characteristics of the sap were measured before and after fermentation process by High-Performance Liquid Chromatography (HPLC and the microbiological quality were also performed. HPLC analysis showed that glucose and fructose concentration in palm sap were 37.0 and 27.6 g/L respectively, ethanol content was ranged between 2.76 and 5.31 % (g/mL for controlled fermentation and 2.20 % (g/mL for spontaneous fermentation. Lactic and acetic acids were ranged between 0.1 and 0.3 g/L and 1.5 and 1.6 g/L for controlled fermentation versus 2.5 and 3.1 g/L and the spontaneous fermentation respectively. Coliforms and Staphylococcus aureus were detected only in the unfermented palm sap and the wine fermented spontaneously. Principal component analysis showed a good separation between spontaneous and controlled fermentation. Sterilization and controlled fermentation of the unfermented sap with palm wine Saccharomyces cerevisiae strains led to the improvement of palm wine quality.

Strain rate measurement by Electronic Speckle Pattern Interferometry: A new look at the strain localization onset

International Nuclear Information System (INIS)

Guelorget, Bruno; Francois, Manuel; Vial-Edwards, Cristian; Montay, Guillaume; Daniel, Laurent; Lu, Jian

2006-01-01

In-plane Electronic Speckle Pattern Interferometry has been successfully used during tensile testing of semi-hard copper sheets in order to measure the strain rate. On one hand, heterogeneity in strain rate field has been found before the maximum of the tensile force (ε t ≅ 19.4 and 25.4%, respectively). Thus, a localization phenomenon occurs before the classic Considere's criterion (dF = 0) for the diffuse neck initiation. On the other hand, strain rate measurement before fracture shows the moment where one of the two slip band systems becomes predominant, then strain concentrates in a small area, the shear band. Uncertainty evaluation has been carried out, which shows a very good accuracy of the total strain and the strain rate measurements

Strain rate measurement by Electronic Speckle Pattern Interferometry: A new look at the strain localization onset

Energy Technology Data Exchange (ETDEWEB)

Guelorget, Bruno [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)]. E-mail: bruno.guelorget@utt.fr; Francois, Manuel [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France); Vial-Edwards, Cristian [Departemento de Ingenieria Mecanica y Metalurgica, Pontificia Universidad Catolica de Chile, Vicuna Mackenna 4860, 6904411 Santiago (Chile); Montay, Guillaume [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France); Daniel, Laurent [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France); Lu, Jian [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)

2006-01-15

In-plane Electronic Speckle Pattern Interferometry has been successfully used during tensile testing of semi-hard copper sheets in order to measure the strain rate. On one hand, heterogeneity in strain rate field has been found before the maximum of the tensile force ({epsilon} {sup t} {approx_equal} 19.4 and 25.4%, respectively). Thus, a localization phenomenon occurs before the classic Considere's criterion (dF = 0) for the diffuse neck initiation. On the other hand, strain rate measurement before fracture shows the moment where one of the two slip band systems becomes predominant, then strain concentrates in a small area, the shear band. Uncertainty evaluation has been carried out, which shows a very good accuracy of the total strain and the strain rate measurements.

Constant pH Accelerated Molecular Dynamics Investigation of the pH Regulation Mechanism of Dinoflagellate Luciferase.

Science.gov (United States)

Donnan, Patrick H; Ngo, Phong D; Mansoorabadi, Steven O

2018-01-23

The bioluminescence reaction in dinoflagellates involves the oxidation of an open-chain tetrapyrrole by the enzyme dinoflagellate luciferase (LCF). The activity of LCF is tightly regulated by pH, where the enzyme is essentially inactive at pH ∼8 and optimally active at pH ∼6. Little is known about the mechanism of LCF or the structure of the active form of the enzyme, although it has been proposed that several intramolecularly conserved histidine residues in the N-terminal region are important for the pH regulation mechanism. Here, constant pH accelerated molecular dynamics was employed to gain insight into the conformational activation of LCF induced by acidification.

Fatigue crack nucleation of type 316LN stainless steel

International Nuclear Information System (INIS)

Kim, Dae Whan; Kim, Woo Gon; Hong, Jun Hwa; Ryu, Woo Seog

2000-01-01

Low Cycle Fatigue (LCF) life decreases drastically with increasing temperature but increases with the addition of nitrogen at room and high temperatures. The effect of nitrogen on LCF life may be related to crack nucleation at high temperatures in austenitic stainless steel because the fraction of crack nucleation in LCF life is about 40%. The influence of nitrogen on the crack nucleation of LCF in type 316LN stainless steel is investigated by observations of crack population and crack depth after testing at 40% of fatigue life. Nitrogen increases the number of cycles to nucleate microcracks of 100 μm but decreases the crack population

Nuclear magnetic resonance probe head design for precision strain control

International Nuclear Information System (INIS)

Kissikov, T.; Sarkar, R.; Bush, B. T.; Lawson, M.; Canfield, P. C.; Curro, N. J.

2017-01-01

Here, we present the design and construction of an NMR probe to investigate single crystals under strain at cryogenic temperatures. The probe head incorporates a piezoelectric-based apparatus from Razorbill Instruments that enables both compressive and tensile strain tuning up to strain values on the order of 0.3% with a precision of 0.001%. 75 As NMR in BaFe 2 As 2 reveals large changes to the electric field gradient and indicates that the strain is homogeneous to within 16% over the volume of the NMR coil.

Analysis of bacterial strains from contaminated and non ...

African Journals Online (AJOL)

Administrator

2007-05-02

May 2, 2007 ... A total 18 strains were collected from non-contaminated and contaminated environments, and were purified. All purified strains were characterized for Gram reaction and biochemical analysis. Screening for bioplastic production was done by Sudan black staining. Strains isolated from non-contaminated.

Material properties for reactor pressure vessels and containment shells under dynamic loading

International Nuclear Information System (INIS)

Albertini, C.

1997-01-01

The effects of high strain rate, dynamic biaxial loading and deformation mode (tension, shear) on the mechanical properties of AISI 316 austenitic stainless steel in as-received and pre-damaged (creep, LCF) conditions are reported. This research was conducted to assess the performances of the containment shell of fast breeder reactors. The results of this research have been utilized to prepare similar investigations for SA 537 Class 1 ferritic steel used for the containment shell of LWR. The first results of these investigations are reported. A programme to study the mechanical properties of plain concrete with real size aggregate at high strain rate is described. (orig.)

Controlled fermentation of Moroccan picholine green olives by oleuropein-degrading Lactobacilli strains

Directory of Open Access Journals (Sweden)

Ghabbour, N.

2016-06-01

Full Text Available The control of the spontaneous fermentation process of un-debittered Moroccan Picholine green olives was undertaken basing the inoculation with two lactobacilli strains (Lactobacillus plantarum S175 and Lactobacillus pentosus S100. These strains, previously selected in our laboratory for their oleuropein-degrading capacity, were inoculated in olives brined at 5% of NaCl, and then incubated at 30 ÅãC. The physico-chemical parameters (pH, free acidity, reducing sugars, sodium chloride, oleuropein and its hydrolysis products, and the microbiological parameters (mesophilic aerobic bacteria, coliforms, Staphylococcus, lactic acid bacteria and yeasts and moulds, were regularly analyzed during the fermentation time. The results obtained showed the effectiveness of the lactic acid bacteria strains to develop suitable oleuropein biodegradation and controlled lactic fermentation processes more than the un-inoculated olives (control. This result was confirmed by the rapid elimination of coliforms and staphylococcus, the accumulation of hydroxytyrosol as a result of oleuropein biodegradation, and a drastic reduction in spoiled olives with good quality fermented olives.Se llevó a cabo el control del proceso de fermentación espontánea de aceitunas verdes sin desamargar picholine marroquí basado en la inoculación con dos cepas de lactobacilos (Lactobacillus plantarum S175 y Lactobacillus pentosus S100. Estas cepas, seleccionadas previamente en nuestro laboratorio por su capacidad de degradar a la oleuropeína, se inocularon en las aceitunas en salmuera al 5 % de NaCl, y después se incubaron a 30 °C. Los parámetros físico-químicos (pH, acidez libre, reducción de azúcares, cloruro sódico, oleuropeína y sus productos de hidrólisis y los parámetros microbiológicos (bacterias aerobias mesófilas, coliformes, estafilococos, bacterias lácticas y levaduras y mohos, fueron analizados regularmente durante el tiempo de fermentación. Los resultados

Crack behaviour of ferritic pressure vessels steels in oxygenated high temperature water under transient loadings. Crack corrosion phase 2. Crack development and fatigue. Final report; Rissverhalten ferritischer Druckbehaelterstaehle in sauerstoffhaltigem Hochtemperaturwasser bei transienten Vorgaengen. Risskorrosion Phase 2. Rissentstehung und Ermuedung. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Weissenberg, Thomas

2014-03-15

Using the example of the ferritic steels 22NiMoCr3-7 and 15MnNi6-3 representative for Nuclear Power Plants experimental data for the evaluation of the influence of the light water reactor (LWR) coolant environment and postulated chloride contaminations on crack development and fatigue have been determined in order to verify and extend the basis for a reliable estimation of the residual service life of reactor components. The aim of the research project was the investigation of the environmental effects at low strain rate conditions and the determination of the fatigue life under cyclic loading at uniaxial and multiaxial stress state. The quasi-static tensile tests (Constant Extension Rate Test, CERT) were performed using 3 low strain rates, each differing by about one order of magnitude (2.5.10{sup -3}, 3.1.10{sup -4} and 2.3.10{sup -5} %/s). The low cycle fatigue (LCF) experiments were conducted applying alternating tensile-compression loading with strain amplitudes of 0.3, 0.5 and 0.9 % at strain rates of 0.1 and 0.01 %/s (tests in air primarily 0.1 %/s). The cyclic notched tensile tests were carried out with a nominal axial strain in the notch root of 0.5 % at a strain rate of 0.1 %/s. The experiments in each case were performed in air, high purity water and chloride containing water at a testing temperature of 240 C, the oxygen content of the liquid medium was set to 0.4 ppm (simulated boiling water reactor coolant). In the CERT experiments chloride contents of 30, 50 and 100 ppb were applied, in the LCF tests the chloride content was 50 ppb which can be regarded as an upper realistic limit for a postulated chloride contamination of the reactor coolant. All experiments in liquid environment were preceded by a pre-autoclaving phase of at least 100 h in order to allow the formation of a stable oxide layer (magnetite). The testing material 22NiMoCr3-7 was available in form of an original reactor pressure vessel shell primarily designated for the German nuclear

Crack behaviour of ferritic pressure vessels steels in oxygenated high temperature water under transient loadings. Crack corrosion phase 2. Crack development and fatigue. Final report

International Nuclear Information System (INIS)

Weissenberg, Thomas

2014-03-01

Using the example of the ferritic steels 22NiMoCr3-7 and 15MnNi6-3 representative for Nuclear Power Plants experimental data for the evaluation of the influence of the light water reactor (LWR) coolant environment and postulated chloride contaminations on crack development and fatigue have been determined in order to verify and extend the basis for a reliable estimation of the residual service life of reactor components. The aim of the research project was the investigation of the environmental effects at low strain rate conditions and the determination of the fatigue life under cyclic loading at uniaxial and multiaxial stress state. The quasi-static tensile tests (Constant Extension Rate Test, CERT) were performed using 3 low strain rates, each differing by about one order of magnitude (2.5.10 -3 , 3.1.10 -4 and 2.3.10 -5 %/s). The low cycle fatigue (LCF) experiments were conducted applying alternating tensile-compression loading with strain amplitudes of 0.3, 0.5 and 0.9 % at strain rates of 0.1 and 0.01 %/s (tests in air primarily 0.1 %/s). The cyclic notched tensile tests were carried out with a nominal axial strain in the notch root of 0.5 % at a strain rate of 0.1 %/s. The experiments in each case were performed in air, high purity water and chloride containing water at a testing temperature of 240 C, the oxygen content of the liquid medium was set to 0.4 ppm (simulated boiling water reactor coolant). In the CERT experiments chloride contents of 30, 50 and 100 ppb were applied, in the LCF tests the chloride content was 50 ppb which can be regarded as an upper realistic limit for a postulated chloride contamination of the reactor coolant. All experiments in liquid environment were preceded by a pre-autoclaving phase of at least 100 h in order to allow the formation of a stable oxide layer (magnetite). The testing material 22NiMoCr3-7 was available in form of an original reactor pressure vessel shell primarily designated for the German nuclear power plant

Generation of localized strain in a thin film piezoelectric to control individual magnetoelectric heterostructures

Energy Technology Data Exchange (ETDEWEB)

Cui, Jizhai; Liang, Cheng-Yen; Sepulveda, Abdon; Carman, Gregory P.; Lynch, Christopher S., E-mail: cslynch@seas.ucla.edu [Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095 (United States); Paisley, Elizabeth A.; Ihlefeld, Jon F. [Electronic, Optical, and Nano Materials Department, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

2015-08-31

Experimental results demonstrate the ability of a surface electrode pattern to produce sufficient in-plane strain in a PbZr{sub 0.52}Ti{sub 0.48}O{sub 3} (PZT) thin film clamped by a Si substrate to control magnetism in a 1000 nm diameter Ni ring. The electrode pattern and the Ni ring/PZT thin film heterostructure were designed using a finite element based micromagnetics code. The magnetoelectric heterostructures were fabricated on the PZT film using e-beam lithography and characterized using magnetic force microscopy. Application of voltage to the electrodes moved one of the “onion” state domain walls. This method enables the development of complex architectures incorporating strain-mediated multiferroic devices.

Role Strain in Collegiate Athletic Training Approved Clinical Instructors

Science.gov (United States)

Henning, Jolene M; Weidner, Thomas G

2008-01-01

Context: Certified athletic trainers who serve as Approved Clinical Instructors (ACIs) in the collegiate setting are balancing various roles (eg, patient care and related administrative tasks, clinical education). Whether this balancing act is associated with role strain in athletic trainers has not been examined. Objective: To examine the degree of, and contributing factors (eg, socialization experiences, professional and employment demographics, job congruency) to, role strain in collegiate ACIs. Design: Cross-sectional survey design. Setting: Geographically stratified random sample of ACIs affiliated with accredited athletic training education programs at National Collegiate Athletic Association (NCAA) Division I, II, and III institutions. Patients or Other Participants: 118 collegiate ACIs (47 head athletic trainers, 45 assistant athletic trainers, 26 graduate assistant athletic trainers). Main Outcome Measure(s): The Athletic Training ACI Role Strain Inventory, which measures total degree of role strain, 7 subscales of role strain, socialization experiences, professional and employment characteristics, and congruency in job responsibilities. Results: A total of 49% (n  =  58) of the participants experienced a moderate to high degree of role strain. Role Overload was the highest contributing subscale to total role strain. No differences were noted between total role strain and role occupant groups, NCAA division, or sex. Graduate assistant athletic trainers experienced a greater degree of role incompetence than head athletic trainers did (P  =  .001). Division II ACIs reported a greater degree of inter-role conflict than those in Division I (P  =  .02). Female ACIs reported a greater degree of role incompetence than male ACIs (P  =  .01). Those ACIs who stated that the ACI training provided by their institution did not adequately prepare them for the role as an ACI experienced greater role strain (P < .001). Conclusions: The ACIs in the

The demand-control model for job strain: a commentary on different ways to operationalize the exposure variable

Directory of Open Access Journals (Sweden)

Márcia Guimarães de Mello Alves

2015-01-01

Full Text Available Demand-control has been the most widely used model to study job strain in various countries. However, researchers have used the model differently, thus hindering the comparison of results. Such heterogeneity appears in both the study instrument used and in the definition of the main exposure variable - high strain. This cross-sectional study aimed to assess differences between various ways of operationalizing job strain through association with prevalent hypertension in a cohort of workers (Pro-Health Study. No difference in the association between high job strain and hypertension was found according to the different ways of operationalizing exposure, even though prevalence varied widely, according to the adopted form, from 19.6% for quadrants to 42% for subtraction tertile. The authors recommend further studies to define the cutoff for exposure variables using combined subjective and objective data.

Differing effects of 2 active dried yeast (Saccharomyces cerevisiae) strains on ruminal acidosis and methane production in nonlactating dairy cows.

Science.gov (United States)

Chung, Y-H; Walker, N D; McGinn, S M; Beauchemin, K A

2011-05-01

Fifteen ruminally cannulated, nonlactating Holstein cows were used to measure the effects of 2 strains of Saccharomyces cerevisiae, fed as active dried yeasts, on ruminal pH and fermentation and enteric methane (CH(4)) emissions. Nonlactating cows were blocked by total duration (h) that their ruminal pH was below 5.8 during a 6-d pre-experimental period. Within each block, cows were randomly assigned to control (no yeast), yeast strain 1 (Levucell SC), or yeast strain 2 (a novel strain selected for enhanced in vitro fiber degradation), with both strains (Lallemand Animal Nutrition, Montréal, QC, Canada) providing 1 × 10(10) cfu/head per day. Cows were fed once daily a total mixed ration consisting of a 50:50 forage to concentrate ratio (dry matter basis). The yeast strains were dosed via the rumen cannula daily at the time of feeding. During the 35-d experiment, ruminal pH was measured continuously for 7 d (d 22 to 28) by using an indwelling system, and CH(4) gas was measured for 4 d (d 32 to 35) using the sulfur hexafluoride tracer gas technique (with halters and yokes). Rumen contents were sampled on 2 d (d 22 and 26) at 0, 3, and 6h after feeding. Dry matter intake, body weight, and apparent total-tract digestibility of nutrients were not affected by yeast feeding. Strain 2 decreased the average daily minimum (5.35 vs. 5.65 or 5.66), mean (5.98 vs. 6.24 or 6.34), and maximum ruminal pH (6.71 vs. 6.86 or 6.86), and prolonged the time that ruminal pH was below 5.8 (7.5 vs. 3.3 or 1.0 h/d) compared with the control or strain 1, respectively. The molar percentage of acetate was lower and that of propionate was greater in the ruminal fluid of cows receiving strain 2 compared with cows receiving no yeast or strain 1. Enteric CH(4) production adjusted for intake of dry matter or gross energy, however, did not differ between either yeast strain compared with the control but it tended to be reduced by 10% when strain 2 was compared with strain 1. The study shows that

Control of protein synthesis in Escherichia coli: strain differences in control of translational initiation after energy source shift-down.

Science.gov (United States)

Jacobson, L A; Jen-Jacobson, L

1980-06-01

We have studied the parameters of protein synthesis in a number of Escherichia coli strains after a shift-down from glucose-minimal to succinate-minimal medium. One group of strains, including K-12(lambda) (ATCC 10798) and NF162, showed a postshift translational yield of 50 to 65% and a 2- to 2.5-fold increase in the functional lifetime of general messenger ribonucleic acid. There was no change in the lag time for beta-galactosidase induction in these strains after the shift-down. A second group, including W1 and W2, showed no reduction in translational yield, no change in the functional lifetime of messenger ribonucleic acid, and a 50% increase in the lag time for beta-galactosidase induction. Evidence is presented which indicates that this increased lag time is not the result of a decreased rate of polypeptide chain propagation. A third group of strains, including NF161, CP78, and NF859, showed an intermediate pattern: translational yield was reduced to about 75% of normal, and the messenger ribonucleic acid functional lifetime was increased by about 50%. Calculation of the relative postshift rates of translational initiation gave about 0.2, 1.0, and 0.5, respectively, for the three groups. There was no apparent correlation between the ability to control translation and the genotypes of these strains at the relA, relX, or spoT loci. Measurements of the induction lag for beta-galactosidase during short-term glucose starvation or after a down-shift induced by alpha-methylglucoside indicated that these regimens elicit responses that are physiologically distinct from those elicited by a glucose-to-succinate shift-down.

Low Cycle Fatigue of Steel in Strain Controled Cyclic Bending

Directory of Open Access Journals (Sweden)

Kulesa Anna

2016-03-01

Full Text Available The paper presents a comparison of the fatigue life curves based on test of 15Mo3 steel under cyclic, pendulum bending and tension-compression. These studies were analyzed in terms of a large and small number of cycles where strain amplitude is dependent on the fatigue life. It has been shown that commonly used Manson-Coffin-Basquin model cannot be used for tests under cyclic bending due to the impossibility of separating elastic and plastic strains. For this purpose, some well-known models of Langer and Kandil and one new model of authors, where strain amplitude is dependent on the number of cycles, were proposed. Comparing the results of bending with tension-compression it was shown that for smaller strain amplitudes the fatigue life for both test methods were similar, for higher strain amplitudes fatigue life for bending tests was greater than for tension-compression.

Strain rate dependent tensile behavior of advanced high strength steels: Experiment and constitutive modeling

International Nuclear Information System (INIS)

Kim, Ji-Hoon; Kim, Daeyong; Han, Heung Nam; Barlat, F.; Lee, Myoung-Gyu

2013-01-01

High strain rate tensile tests were conducted for three advanced high strength steels: DP780, DP980 and TRIP780. A high strain rate tensile test machine was used for applying the strain rate ranging from 0.1/s to 500/s. Details of the measured stress–strain responses were comparatively analyzed for the DP780 and TRIP780 steels which show similar microstructural feature and ultimate tensile strength, but different strengthening mechanisms. The experimental observations included: usual strain rate dependent plastic flow stress behavior in terms of the yield stress (YS), the ultimate tensile strength (UTS), the uniform elongation (UE) and the total elongation (TE) which were observed for the three materials. But, higher strain hardening rate at early plastic strain under quasi-static condition than that of some increased strain rates was featured for TRIP780 steel, which might result from more active transformation during deformation with lower velocity. The uniform elongation that explains the onset of instability and the total elongation were larger in case of TRIP steel than the DP steel for the whole strain rate range, but interestingly the fracture strain measured by the reduction of area (RA) method showed that the TRIP steel has lower values than DP steel. The fractographs using scanning electron microscopy (SEM) at the fractured surfaces were analyzed to relate measured fracture strain and the microstructural difference of the two materials during the process of fracture under various strain rates. Finally, constitutive modeling for the plastic flow stresses under various strain rates was provided in this study. The proposed constitutive law could represent both Hollomon-like and Voce-like hardening laws and the ratio between the two hardening types was efficiently controlled as a function of strain rate. The new strength model was validated successfully under various strain rates for several grades of steels such as mild steels, DP780, TRIP780, DP980 steels.

Effectiveness of Shot Peening In Suppressing Fatigue Cracking At Non-Metallic Inclusions In Udimet(Registered Trademark)720

Science.gov (United States)

Barrie, Robert L.; Gabb, Timothy P.; Telesman, Jack; Kantzos, Peter T.; Prescenzi, Anthony; Biles, T.; Bonacuse, P. J.

2006-01-01

The fatigue lives of modern powder metallurgy disk alloys can be reduced over an order of magnitude by cracking at inherent non-metallic inclusions. The objective of this work was to study the effectiveness of shot peening in suppressing LCF crack initiation and growth at surface nonmetallic inclusions. Inclusions were carefully introduced at elevated levels during powder metallurgy processing of the nickel-base disk superalloy Udimet 720. Multiple strain-controlled fatigue tests were then performed on machined specimens with and without shot peened test sections at 427 C and 650 C. The low cycle fatigue lives and failure initiation sites varied as functions of inclusion content, shot peening, and fatigue conditions. A large majority of the failures in as-machined specimens with the introduced inclusions occurred at cracks initiating from inclusions intersecting the specimen surface. These inclusions reduced fatigue life by up to 100X, when compared to lives of material without inclusions residing at specimen surface. Large inclusions produced the greatest reductions in life for tests at low strain ranges and high strain ratios. Shot peening improved life in many cases by reducing the most severe effects of inclusions.

[Molecular typing of 12 Brucella strains isolated in Guizhou province in 2010-2013].

Science.gov (United States)

Wang, Yue; Chen, Hong; Liu, Ying; Zhou, Jingzhu; Li, Shijun; Hang, Yan; Tang, Guangpeng; Wang, Dingming; Chen, Guichun

2015-09-01

To identify and characterize the Brucella strains from Guizhou province in 2010-2013. A total of 12 strains of Brucella suspicious bacteria were isolated in Guizhou province from 2010 to 2013. Four strains (GZLL3, GZLL4, GZLL11 and SH2) were isolated from goat blood samples and eight strains (SH4, GZZY, GZSQ, GZZA, BR13001, BR13004, BR13005 and BR13006) were isolated from blood samples of patient 12 Brucella suspicious strains were identified and characterized using conventional methods. Brucella genus specific gene BCSP31-based PCR (BCSP31-PCR) was used to identify the genus of Brucella and IS711 insert sequence-based PCR (AMOS-PCR) was applied to identify the species of Brucella strains. Goats and patients originated Brucella strains were comparatively analysed using Pulse-field Gel Electrophoresis (PFGE). Both of conventional methods and PCR identified the 12 Brucella suspicious strains as B. melitensis biotype 3. BCSP31-PCR identification results showed that a specific DNA bands (223 bp) were detected in all the 12 strains and positive control samples with no DNA band in negative samples. AMOS-PCR amplified a 731 bp-DNA bands in all the 12 strains, with 731 bp, 498 bp and 275 bp in M5, S2 and A19 strains, respectively, and no DNA band was detected in the negative control samples. PFGE analysis showed that 12 Brucella isolates from patients and goats showed consistent PFGE patterns with the digestion of restriction enzyme Xba I. The epidemic species/type of Brucella in both human and animal in Guizhou province was B. melitensis biotype 3 and goat was the main animal source of infection of brucellosis in Guizhou province.

Total synthesis and related studies of large, strained, and bioactive natural products

Science.gov (United States)

HIRAMA, Masahiro

2016-01-01

Our chemical syntheses and related scientific investigations of natural products with complex architectures and powerful biological activities are described, focusing on the very large 3 nm-long polycyclic ethers called the ciguatoxins, highly strained and labile chromoprotein antitumor antibiotics featuring nine-membered enediyne cores, and extremely potent anthelmintic macrolides called the avermectins. PMID:27725470

Magnetic properties of cyclically deformed austenite

Energy Technology Data Exchange (ETDEWEB)

Das, Arpan, E-mail: dasarpan1@yahoo.co.in

2014-06-01

In meta-stable austenitic stainless steels, low cycle fatigue deformation is accompanied by a partial stress/strain-induced solid state phase transformation of paramagnetic γ(fcc) austenite phase to ferromagnetic α{sup /}(bcc) martensite. The measured characteristic of magnetic properties, which are the saturation magnetization, susceptibility, coercivity, retentivity, and the area under the magnetic hysteresis loop are sensitive to the total strain amplitude imposed and the corresponding material behaviour. The morphologies and nucleation characteristics of deformation induced martensites (i.e., ϵ(hcp), α{sup /}(bcc)) have been investigated through analytical transmission electron microscope. It has been observed that deformation induced martensites can nucleate at a number of sites (i.e., shear band intersections, isolated shear bands, shear band–grain boundary intersection, grain boundary triple points, etc.) through multiple transformation sequences: γ(fcc)→ϵ(hcp), γ(fcc)→ϵ(hcp)→α{sup /}(bcc), γ(fcc)→ deformation twin →α{sup /}(bcc) and γ(fcc)→α{sup /}(bcc). - Highlights: • LCF tests were done at various strain amplitudes of 304LNSS. • Quantification of martensite was done through ferritecope. • Magnetic properties were characterised through VSM. • Correlation of magnetic properties with the cyclic plastic response was done. • TEM was done to investigate the transformation micro-mechanisms.

Strain controlled switching effects in phosphorene and GeS.

Science.gov (United States)

Li, B W; Wang, Y; Xie, Y Q; Zhu, L; Yao, K L

2017-10-27

By performing first principles calculations within the combined approach of density functional theory and nonequilibrium Green's function technique, we have designed some nanoelectronic devices to explore the ferroelastic switching of phosphorene and phosphorene analogs GeS. With the structure swapping along the zigzag direction and armchair direction, band gap transformed at different states due to their anisotropic phosphorene-like structure. From the initial state to the middle state, the band gap becomes progressively smaller, after that, it becomes wide. By analyzing transmission coefficients, it is found that the transport properties of phosphorene and GeS can be controlled by a uniaxial strain. The results also manifest that GeS has great potential to fabricate ferroic nonvolatile memory devices, because its relatively high on/off transmission coefficient ratio (∼1000) between the two stable ferroelastic states.

Effects of tibial plateau angle and spacer thickness applied during in vitro canine total knee replacement on three-dimensional kinematics and collateral ligament strain.

Science.gov (United States)

Baker, Katherine M; Foutz, Timothy L; Johnsen, Kyle J; Budsberg, Steven C

2014-09-01

To quantify the 3-D kinematics and collateral ligament strain of stifle joints in cadaveric canine limbs before and after cranial cruciate ligament transection followed by total knee replacement (TKR) involving various tibial plateau angles and spacer thicknesses. 6 hemi-pelvises collected from clinically normal nonchondrodystrophic dogs (weight range, 25 to 35 kg). Hemi-pelvises were mounted on a modified Oxford knee rig that allowed 6 degrees of freedom of the stifle joint but prevented mechanical movement of the hip and tarsal joints. Kinematics and collateral ligament strain were measured continuously while stifle joints were flexed. Data were again collected after cranial cruciate ligament transection and TKR with combinations of 3 plateau angles (0°, 4°, and 8°) and spacer thicknesses (5, 7, and 9 mm). Presurgical (ie, normal) stifle joint rotations were comparable to those previously documented for live dogs. After TKR, kinematics recorded for the 8°, 5-mm implant most closely resembled those of unaltered stifle joints. Decreasing the plateau angle and increasing spacer thickness altered stifle joint adduction, internal rotation, and medial translation. Medial collateral ligament strain was minimal in unaltered stifle joints and was unaffected by TKR. Lateral collateral ligament strain decreased with steeper plateau angles but returned to a presurgical level at the flattest plateau angle. Among the constructs tested, greatest normalization of canine stifle joint kinematics in vitro was achieved with the steepest plateau angle paired with the thinnest spacer. Furthermore, results indicated that strain to the collateral ligaments was not negatively affected by TKR.

Statistical analysis of elevated-temperature, strain-controlled fatigue data on Type 304 stainless steel

International Nuclear Information System (INIS)

Diercks, D.R.; Raske, D.T.

1976-01-01

The available elevated-temperature, strain-controlled, uniaxial fatigue data on Type 304 stainless steel (435 data points) are summarized, and variables that influence cyclic life are divided into first- and second-order categories. The first-order variables, which include strain range, strain rate, temperature, and tensile hold time, were used in a multivariable regression analysis to describe the observed variation in fatigue life. Goodness of fit with respect to these variables as well as the appropriateness of the transformations employed are discussed. Confidence intervals are estimated, and a comparison with the ASME Boiler and Pressure Vessel Code Case 1592 creep-fatigue design curve is made for a particular set of conditions. The second-order variables include the laboratories at which the data were generated, the different heats from which the test specimens were fabricated, and the heat treatments that preceded testing. These variables were statistically analyzed to determine their effect on fatigue life. The results are discussed, and the heats and heat treatments that are most resistant to fatigue damage under these loading and environmental conditions are identified

Stress strain modelling of casting processes in the framework of the control volume method

DEFF Research Database (Denmark)

Hattel, Jesper; Andersen, Søren; Thorborg, Jesper

1998-01-01

Realistic computer simulations of casting processes call for the solution of both thermal, fluid-flow and stress/strain related problems. The multitude of the influencing parameters, and their non-linear, transient and temperature dependent nature, make the calculations complex. Therefore the nee......, the present model is based on the mainly decoupled representation of the thermal, mechanical and microstructural processes. Examples of industrial applications, such as predicting residual deformations in castings and stress levels in die casting dies, are presented...... for fast, flexible, multidimensional numerical methods is obvious. The basis of the deformation and stress/strain calculation is a transient heat transfer analysis including solidification. This paper presents an approach where the stress/strain and the heat transfer analysis uses the same computational...... domain, which is highly convenient. The basis of the method is the control volume finite difference approach on structured meshes. The basic assumptions of the method are shortly reviewed and discussed. As for other methods which aim at application oriented analysis of casting deformations and stresses...

Microgrid Stability Controller Based on Adaptive Robust Total SMC

DEFF Research Database (Denmark)

Su, Xiaoling; Han, Minxiao; Guerrero, Josep M.

2015-01-01

This paper presents a microgrid stability controller (MSC) in order to provide existing DGs the additional functionality of working in islanding mode without changing their control strategies in grid-connected mode and to enhance the stability of the microgrid. Microgrid operating characteristics....... The MSC provides fast dynamic response and robustness to the microgrid. When the system is operating in grid-connected mode, it is able to improve the controllability of the exchanged power between the microgrid and the utility grid, while smoothing DG’s output power. When the microgrid is operating...... and mathematical models of the MSC indicate that the system is inherently nonlinear and time-variable. Therefore, this paper proposes an adaptive robust total sliding-mode control (ARTSMC) system for the MSC. It is proved that the ARTSMC system is insensitive to parametric uncertainties and external disturbances...

Mean strain effects on the random cyclic strain-life relations of 0Cr18Ni10Ti pipe steel

International Nuclear Information System (INIS)

Zhao Yongxiang; Yang Bing

2005-01-01

Experimental study is performed on the mean strain effects on the random cyclic strain-life relations of the new nuclear material, 0Cr18Ni10Ti pipe steel. In order to save costs of specimens and tests, an improved maximum likelihood fatigue test method is applied to manage the present strain-controlled fatigue tests. Six straining ratios, respectively, -1, -0.52, 0.22, 0.029, 0.18, and 0.48, are applied to study the effects. Total 104 specimens are fatigued. Since the material exhibits an entirely relaxation effect of mean stress under the six ratios and, in addition, there is no effectively method for the description of the mean straining effects under this case, previous Zhao's random strain-life relations are therefore applied for effective characterization of the scattering test data under the six ratios on a basis of Coffin-Manson equation.Then the effects of the ratios are analyzed respectively on the average fatigue lives, the standard deviations of the logarithms of fatigue lives, and the fatigue lives under different survival probabilities and confidences. The results reveal that the ratios greater than zero exhibit a positive effect of about 1.3 to 1.6 times under the survival probability of 0.999 and the confidence of 95%. A negative effect is exhibited for the case of the ratios less than zero. In addition, the assessment of the effects from the sense of average fatigue lives might result in a wrong conclusion for the practice of higher reliabilities. The effects can be appropriately assessed from a probabilistic sense to take into account the average lives, the scattering regularity of test data, and the size of sampling. (author)

Strains and Stressors: An Analysis of Touchscreen Learning in Genetically Diverse Mouse Strains

Science.gov (United States)

Graybeal, Carolyn; Bachu, Munisa; Mozhui, Khyobeni; Saksida, Lisa M.; Bussey, Timothy J.; Sagalyn, Erica; Williams, Robert W.; Holmes, Andrew

2014-01-01

Touchscreen-based systems are growing in popularity as a tractable, translational approach for studying learning and cognition in rodents. However, while mouse strains are well known to differ in learning across various settings, performance variation between strains in touchscreen learning has not been well described. The selection of appropriate genetic strains and backgrounds is critical to the design of touchscreen-based studies and provides a basis for elucidating genetic factors moderating behavior. Here we provide a quantitative foundation for visual discrimination and reversal learning using touchscreen assays across a total of 35 genotypes. We found significant differences in operant performance and learning, including faster reversal learning in DBA/2J compared to C57BL/6J mice. We then assessed DBA/2J and C57BL/6J for differential sensitivity to an environmental insult by testing for alterations in reversal learning following exposure to repeated swim stress. Stress facilitated reversal learning (selectively during the late stage of reversal) in C57BL/6J, but did not affect learning in DBA/2J. To dissect genetic factors underlying these differences, we phenotyped a family of 27 BXD strains generated by crossing C57BL/6J and DBA/2J. There was marked variation in discrimination, reversal and extinction learning across the BXD strains, suggesting this task may be useful for identifying underlying genetic differences. Moreover, different measures of touchscreen learning were only modestly correlated in the BXD strains, indicating that these processes are comparatively independent at both genetic and phenotypic levels. Finally, we examined the behavioral structure of learning via principal component analysis of the current data, plus an archival dataset, totaling 765 mice. This revealed 5 independent factors suggestive of “reversal learning,” “motivation-related late reversal learning,” “discrimination learning,” “speed to respond,” and �

Low Cycle Fatigue of Composite Materials in Army Structural Applications: A Review of Literature and Recommendations for Research

National Research Council Canada - National Science Library

Harik, Vasyl Michael

2000-01-01

Low cycle fatigue (LCF) of laminate composite structures used in Army applications is assessed to identify the key physical phenomena occurring during LCF processes and to determine their main characteristics...

On the control of ribosomal protein biosynthesis in Escherichia coli

International Nuclear Information System (INIS)

Pichon, J.; Marvaldi, J.; Coeroli, C.; Cozzone, A.; Marchis-Mouren, G.

1977-01-01

The rate of individual ribosomal protein synthesis relative to total protein synthesis has been determined in Escherichia coli rel + and rel - cells, under valyl-tRNA deprivation. These strains have a temperature-sensitive valyl-tRNA synthetase. Starvation was obtained following transfer of the cells to non-permissive temperature. Ribosomal proteins were obtained by treatment of either total lysates of freeze-thawed lysozyme spheroplasts or ammonium sulphate precipitate of ribosomes, with acetic acid. Differential labelling of the ribosomal proteins was observed in both strains: proteins from the rel + strain appear more labelled than those from the rel - strain, the rate of labelling of individual proteins being about the same in both strains. Moreover ribosomal proteins were found as stable during starvation as total protein. It is thus concluded that in starving cells individual ribosomal proteins are not synthesized at equal rates. This indicates that the synthesis of ribosomal proteins is not only under the control of the rel gene

Low cycle fatigue behavior of hot-bent 347 stainless steel in a simulated PWR water environment

Energy Technology Data Exchange (ETDEWEB)

Lee, Jun Ho; Seo, Myung Gyu; Jang, Chang Heui [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Hong, Jong Tae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Tae Soon [Central Research InstituteKorea Hydro and Nuclear Power Co., Ltd., Daejeon (Korea, Republic of)

2016-11-15

The effect of hot bending on the Low cycle fatigue (LCF) behavior of 347 SS was evaluated in Room temperature (RT) air and simulated Pressurized water reactor (PWR) water environments. The LCF life of 347 SS in PWR water was shorter than that in RT air for the as-received and hot-bent conditions. The LCF life of hot-bent 347 SS was relatively longer than that of the as-received condition in both RT air and PWR water. Microstructure analysis indicated development of dislocation structure near niobium carbide particles and increase in dislocation density for the hot-bent 347 SS. Such microstructure acted as barriers to dislocation movement during the LCF test, resulting in minimal hardening for the hot-bent 347 SS in RT air.

Role of scaffold network in controlling strain and functionalities of nanocomposite films.

Science.gov (United States)

Chen, Aiping; Hu, Jia-Mian; Lu, Ping; Yang, Tiannan; Zhang, Wenrui; Li, Leigang; Ahmed, Towfiq; Enriquez, Erik; Weigand, Marcus; Su, Qing; Wang, Haiyan; Zhu, Jian-Xin; MacManus-Driscoll, Judith L; Chen, Long-Qing; Yarotski, Dmitry; Jia, Quanxi

2016-06-01

Strain is a novel approach to manipulating functionalities in correlated complex oxides. However, significant epitaxial strain can only be achieved in ultrathin layers. We show that, under direct lattice matching framework, large and uniform vertical strain up to 2% can be achieved to significantly modify the magnetic anisotropy, magnetism, and magnetotransport properties in heteroepitaxial nanoscaffold films, over a few hundred nanometers in thickness. Comprehensive designing principles of large vertical strain have been proposed. Phase-field simulations not only reveal the strain distribution but also suggest that the ultimate strain is related to the vertical interfacial area and interfacial dislocation density. By changing the nanoscaffold density and dimension, the strain and the magnetic properties can be tuned. The established correlation among the vertical interface-strain-properties in nanoscaffold films can consequently be used to tune other functionalities in a broad range of complex oxide films far beyond critical thickness.

The role of nitrogen uptake on the competition ability of three vineyard Saccharomyces cerevisiae strains.

Science.gov (United States)

Vendramini, Chiara; Beltran, Gemma; Nadai, Chiara; Giacomini, Alessio; Mas, Albert; Corich, Viviana

2017-10-03

Three vineyard strains of Saccharomyces cerevisiae, P301.4, P304.4 and P254.12, were assayed in comparison with a commercial industrial strain, QA23. The aim was to understand if nitrogen availability could influence strain competition ability during must fermentation. Pairwise-strain fermentations and co-fermentations with the simultaneous presence of the four strains were performed in synthetic musts at two nitrogen levels: control nitrogen condition (CNC) that assured the suitable assimilable nitrogen amount required by the yeast strains to complete the fermentation and low nitrogen condition (LNC) where nitrogen is present at very low level. Results suggested a strong involvement of nitrogen availability, as the frequency in must of the vineyard strains, respect to QA23, in LNC was always higher than that found in CNC. Moreover, in CNC only strain P304.4 reached the same strain frequency as QA23. P304.4 competition ability increased during the fermentation, indicating better performance when nitrogen availability was dropping down. P301.4 was the only strain sensitive to QA23 killer toxin. In CNC, when it was co-inoculated with the industrial strain QA23, P301.4 was never detected. In LNC, P301.4 after 12h accounted for 10% of the total population. This percentage increased after 48h (20%). Single-strain fermentations were also run in both conditions and the nitrogen metabolism further analyzed. Fermentation kinetics, ammonium and amino-acid consumptions and the expression of genes under nitrogen catabolite repression evidenced that vineyard yeasts, and particularly strain P304.4, had higher nitrogen assimilation rate than the commercial control. In conclusion, the high nitrogen assimilation rate seems to be an additional strategy that allowed vineyard yeasts successful competition during the growth in grape musts. Copyright © 2017 Elsevier B.V. All rights reserved.

Strain preservation of experimental animals: vitrification of two-cell stage embryos for multiple mouse strains.

Science.gov (United States)

Eto, Tomoo; Takahashi, Riichi; Kamisako, Tsutomu

2015-04-01

Strain preservation of experimental animals is crucial for experimental reproducibility. Maintaining complete animal strains, however, is costly and there is a risk for genetic mutations as well as complete loss due to disasters or illness. Therefore, the development of effective vitrification techniques for cryopreservation of multiple experimental animal strains is important. We examined whether a vitrification method using cryoprotectant solutions, P10 and PEPeS, is suitable for preservation of multiple inbred and outbred mouse strains. First, we investigated whether our vitrification method using cryoprotectant solutions was suitable for two-cell stage mouse embryos. In vitro development of embryos exposed to the cryoprotectant solutions was similar to that of fresh controls. Further, the survival rate of the vitrified embryos was extremely high (98.1%). Next, we collected and vitrified two-cell stage embryos of 14 mouse strains. The average number of embryos obtained from one female was 7.3-33.3. The survival rate of vitrified embryos ranged from 92.8% to 99.1%, with no significant differences among mouse strains. In vivo development did not differ significantly between fresh controls and vitrified embryos of each strain. For strain preservation using cryopreserved embryos, two offspring for inbred lines and one offspring for outbred lines must be produced from two-cell stage embryos collected from one female. The expected number of surviving fetuses obtained from embryos collected from one female of either the inbred or outbred strains ranged from 2.9 to 19.5. The findings of the present study indicated that this vitrification method is suitable for strain preservation of multiple mouse strains. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Atlas of stress-strain curves

CERN Document Server

2002-01-01

The Atlas of Stress-Strain Curves, Second Edition is substantially bigger in page dimensions, number of pages, and total number of curves than the previous edition. It contains over 1,400 curves, almost three times as many as in the 1987 edition. The curves are normalized in appearance to aid making comparisons among materials. All diagrams include metric (SI) units, and many also include U.S. customary units. All curves are captioned in a consistent format with valuable information including (as available) standard designation, the primary source of the curve, mechanical properties (including hardening exponent and strength coefficient), condition of sample, strain rate, test temperature, and alloy composition. Curve types include monotonic and cyclic stress-strain, isochronous stress-strain, and tangent modulus. Curves are logically arranged and indexed for fast retrieval of information. The book also includes an introduction that provides background information on methods of stress-strain determination, on...

Social Learning, Social Control, and Strain Theories: A Formalization of Micro-level Criminological Theories

OpenAIRE

Proctor, Kristopher Ryan

2010-01-01

This dissertation proposes theoretical formalization as a way of enhancing theory development within criminology. Differential association, social learning, social control, and general strain theories are formalized in order to identify assumptions of human nature, key theoretical concepts, theoretical knowledge claims, and scope conditions. The resulting formalization allows greater comparability between theories in terms of explanatory power, and additionally provides insights into integrat...

Strain Specific Factors Control Effector Gene Silencing in Phytophthora sojae.

Directory of Open Access Journals (Sweden)

Sirjana Devi Shrestha

Full Text Available The Phytophthora sojae avirulence gene Avr3a encodes an effector that is capable of triggering immunity on soybean plants carrying the resistance gene Rps3a. P. sojae strains that express Avr3a are avirulent to Rps3a plants, while strains that do not are virulent. To study the inheritance of Avr3a expression and virulence towards Rps3a, genetic crosses and self-fertilizations were performed. A cross between P. sojae strains ACR10 X P7076 causes transgenerational gene silencing of Avr3a allele, and this effect is meiotically stable up to the F5 generation. However, test-crosses of F1 progeny (ACR10 X P7076 with strain P6497 result in the release of silencing of Avr3a. Expression of Avr3a in the progeny is variable and correlates with the phenotypic penetrance of the avirulence trait. The F1 progeny from a direct cross of P6497 X ACR10 segregate for inheritance for Avr3a expression, a result that could not be explained by parental imprinting or heterozygosity. Analysis of small RNA arising from the Avr3a gene sequence in the parental strains and hybrid progeny suggests that the presence of small RNA is necessary but not sufficient for gene silencing. Overall, we conclude that inheritance of the Avr3a gene silenced phenotype relies on factors that are variable among P. sojae strains.

Mumps Hoshino and Torii vaccine strains were distinguished from circulating wild strains.

Science.gov (United States)

Sawada, Akihito; Yamaji, Yoshiaki; Nakayama, Tetsuo

2013-06-01

Aseptic meningitis and acute parotitis have been observed after mumps vaccination. Mumps outbreaks have been reported in Japan because of low vaccine coverage, and molecular differentiation is required to determine whether these cases are vaccine associated. RT-nested PCR was performed in the small hydrophobic gene region, and viruses were differentiated by restriction fragment length polymorphism assay. A total of 584 nucleotides were amplified. The PCR product of the Hoshino strain was cut into two fragments (313 and 271 nucleotides) by MfeI; that of the Torii strain was digested with EcoT22I, resulting in 332- and 252-nucleotide fragments. Both strains were genotype B and had an XbaI site, resulting in two fragments: 299 and 285 nucleotides. Current circulating wild types were cut only by XbaI or MfeI. However, the MfeI site of the wild types was different from that of the Hoshino strain, resulting in 451- and 133-nucleotide fragments. Using three restriction enzymes, two mumps vaccine strains were distinguished from wild types, and this separation was applied to the identification of vaccine-related adverse events.

Fatigue behavior of an insulation system for the ITER magnets in the load and strain controlled mode

International Nuclear Information System (INIS)

Prokopec, R.; Humer, K.; Weber, H.W.

2007-01-01

The application of glass-fiber reinforced plastics as insulation materials for fusion magnet coils (e.g. of ITER) requires a full mechanical material characterization under ITER relevant conditions. The tension-tension fatigue test is useful to simulate the pulsed tokamak operation of the ITER coils in the relevant range of 10 4 -10 5 cycles. The fatigue process can be run under load or strain control, which may influence the material behavior under cyclic load conditions. Therefore, investigations were performed at 77 K using an industrial glass-fiber reinforced composite impregnated with epoxy resin. For both the load and the strain controlled mode, R-values of 0.3 and 0.5 and a frequency of 10 Hz were chosen. The results are discussed with respect to the lifetime performance of ITER

A Biocontrol Strain of Bacillus subtilis WXCDD105 Used to Control Tomato Botrytis cinerea and Cladosporium fulvum Cooke and Promote the Growth of Seedlings

Directory of Open Access Journals (Sweden)

Hui Wang

2018-05-01

Full Text Available In this study, a strain named WXCDD105, which has strong antagonistic effects on Botrytis cinerea and Cladosporium fulvum Cooke, was screened out from the rhizosphere of healthy tomato plants. The tomato plants had inhibition diameter zones of 5.00 mm during the dual culture for four days. Based on the morphological and physiological characteristics, the 16S rDNA sequence, and the gyrB gene sequence analysis, the strain WXCDD105 was identified as Bacillus subtilis suBap. subtilis. The results of the mycelial growth test showed that the sterile filtrate of the strain WXCDD105 could significantly inhibit mycelial growth of Botrytis cinerea and Cladosporium fulvum Cooke. The inhibition rates were 95.28 and 94.44%, respectively. The potting experiment showed that the strain WXCDD105 made effective the control of tomato gray mold and tomato leaf mold. The control efficiencies were 74.70 and 72.07%. The antagonistic test results showed that the strain WXCDD105 had different degrees of inhibition on 10 kinds of plant pathogenic fungi and the average inhibition rates were more than 80%. We also found that the strain WXCDD105 stimulated both the seed germination and seedling growth of tomatoes. Using the fermentation liquid of WXCDD105 (108 cfu·mL−1 to treat the seeds, the germination rate and radicle length were increased. Under the treatment of the fermentation liquid of the strain WXCDD105 (106 cfu·mL−1, nearly all physiological indexes of tomato seedlings were significantly higher than that of the control groups. This could not only keep the nutritional quality of tomato fruits but also prevent them from rotting. This study provided us with an excellent strain for biological control of tomato gray mold, tomato leaf mold, and tomato growth promotion. This also laid the technical foundation for its application.

Determination of dilution and quality control of total and anti ...

African Journals Online (AJOL)

Objective: To determine the correct dilution and Quality control commercial ELISA of total and anti-measles antibodies for HIV infected pregnant women. Design: A laboratory based study. Setting: The University of Nairobi, Department of Paediatrics laboratory. Subjects: HIV infected pregnant women enrolled and exposed to ...

Preparation of progenin III from total steroidal saponins of Dioscorea nipponica Makino using a crude enzyme from Aspergillus oryzae strain.

Science.gov (United States)

Liu, Tingqiang; Yu, Hongshan; Liu, Chunying; Bao, Yongming; Hu, Xiangchun; Wang, Yuanhao; Liu, Bing; Fu, Yaoyao; Tang, Sihui; Jin, Fengxie

2013-05-01

Progenin III, one of the most active spirostanol saponins, is a potential candidate for anti-cancer therapy due to its strong antitumor activity and low hemolytic activity. However, the concentration of progenin III is extremely low in natural Dioscorea plants. In this paper, the progenin III production from total steroidal saponins of Dioscorea nipponica Makino was studied using the crude enzyme from Aspergillus oryzae DLFCC-38. The crude enzyme converting total steroidal saponins into progenin III was obtained from the A. oryzae DLFCC-38 culture. For enzyme production, the strain was cultured for 72 h at 30 °C with shaking at 150 rpm in 5 % (w/v) malt extract medium containing 2 % (v/v) extract of D. nipponica as the enzyme inducer. The crude enzyme converted total steroidal saponins into major progenin III with a high yield when the reaction was carried out for 9 h at 50 °C and pH 5.0 with the 20 mg/ml of substrate. In the preparation of progenin III, 117 g of crude progenin III was obtained from 160 g of substrate, and the crude product was purified with silica gel column to obtain 60.3 g progenin III of 93.4 % purity.

Learning and strain among newcomers: a three-wave study on the effects of Job Demands and Job Control

NARCIS (Netherlands)

Taris, T.W.; Feij, J.A.

2004-01-01

The present 3-wave longitudinal study was an examination of job-related learning and strain as a function of job demand and job control. The participants were 311 newcomers to their jobs. On the basis of R. A. Karasek and T. Theorell's (1990) demand-control model, the authors predicted that high

An ultrasensitive strain sensor with a wide strain range based on graphene armour scales.

Science.gov (United States)

Yang, Yi-Fan; Tao, Lu-Qi; Pang, Yu; Tian, He; Ju, Zhen-Yi; Wu, Xiao-Ming; Yang, Yi; Ren, Tian-Ling

2018-06-12

An ultrasensitive strain sensor with a wide strain range based on graphene armour scales is demonstrated in this paper. The sensor shows an ultra-high gauge factor (GF, up to 1054) and a wide strain range (ε = 26%), both of which present an advantage compared to most other flexible sensors. Moreover, the sensor is developed by a simple fabrication process. Due to the excellent performance, this strain sensor can meet the demands of subtle, large and complex human motion monitoring, which indicates its tremendous application potential in health monitoring, mechanical control, real-time motion monitoring and so on.

MM98.57 Quantification of Combined Strain Paths

DEFF Research Database (Denmark)

Nielsen, Morten Sturgård; Wanheim, Tarras

1998-01-01

this curve into useful scalar relations from experimental data.The strain history for plane strain when assuming volume constancy may be plotted in a shear strain, normal strain diagram, which has the property of showing both the rotation of principal deformation axes during the deformation and the amount...... is to describe the total strain history as a curve in the 6-dimensional shear strain, normal strain space. In order to be able to use these experimental data for calculation, the development of this strain curve must be transformed into a set of scalar relations that may be used for predicting the yield surface...... at a given point in a new strain history. A simple example of this concept is to take the length of the strain curve as describing scalar relation: E.g. to use the equivalent strain as parameter for describing the yield stress. This paper focuses on the strain curve concept and the possibilities to convert...

Laboratory evaluation of a native strain of Beauveria bassiana for controlling Dermanyssus gallinae (De Geer, 1778) (Acari: Dermanyssidae).

Science.gov (United States)

Immediato, Davide; Camarda, Antonio; Iatta, Roberta; Puttilli, Maria Rita; Ramos, Rafael Antonio Nascimento; Di Paola, Giancarlo; Giangaspero, Annunziata; Otranto, Domenico; Cafarchia, Claudia

2015-09-15

The poultry red mite, Dermanyssus gallinae (De Geer, 1778) (Acari: Dermanyssidae) is one of the most economically important ectoparasites of laying hens worldwide. Chemical control of this mite may result in environmental and food contamination, as well as the development of drug resistance. High virulence of Beauveria bassiana sensu lato strains isolated from naturally infected hosts or from their environment has been demonstrated toward many arthropod species, including ticks. However, a limited number of studies have assessed the use of B. bassiana for the control of D. gallinae s.l. and none of them have employed native strains. This study reports the pathogenicity of a native strain of B. bassiana (CD1123) against nymphs and adults of D. gallinae. Batches of nymph and adult mites (i.e., n=720 for each stage) for treated groups (TGs) were placed on paper soaked with a 0.1% tween 80 suspension of B. bassiana (CIS, 10(5), 10(7) and 10(9) conidia/ml), whilst 240 untreated control mites for each stage (CG) were exposed only to 0.1% tween 80. The mites in TG showed a higher mortality at all stages (pbassiana suspension containing 10(9) conidia/ml was highly virulent towards nymph and adult stages of D. gallinae, therefore representing a possible promising natural product to be used in alternative or in combination to other acaricidal compounds currently used for controlling the red mite. Copyright © 2015 Elsevier B.V. All rights reserved.

Strain-engineered growth of two-dimensional materials.

Science.gov (United States)

Ahn, Geun Ho; Amani, Matin; Rasool, Haider; Lien, Der-Hsien; Mastandrea, James P; Ager Iii, Joel W; Dubey, Madan; Chrzan, Daryl C; Minor, Andrew M; Javey, Ali

2017-09-20

The application of strain to semiconductors allows for controlled modification of their band structure. This principle is employed for the manufacturing of devices ranging from high-performance transistors to solid-state lasers. Traditionally, strain is typically achieved via growth on lattice-mismatched substrates. For two-dimensional (2D) semiconductors, this is not feasible as they typically do not interact epitaxially with the substrate. Here, we demonstrate controlled strain engineering of 2D semiconductors during synthesis by utilizing the thermal coefficient of expansion mismatch between the substrate and semiconductor. Using WSe 2 as a model system, we demonstrate stable built-in strains ranging from 1% tensile to 0.2% compressive on substrates with different thermal coefficient of expansion. Consequently, we observe a dramatic modulation of the band structure, manifested by a strain-driven indirect-to-direct bandgap transition and brightening of the dark exciton in bilayer and monolayer WSe 2 , respectively. The growth method developed here should enable flexibility in design of more sophisticated devices based on 2D materials.Strain engineering is an essential tool for modifying local electronic properties in silicon-based electronics. Here, Ahn et al. demonstrate control of biaxial strain in two-dimensional materials based on the growth substrate, enabling more complex low-dimensional electronics.

Effects of Bacillus thuringiensis strains virulent to Varroa destructor on larvae and adults of Apis mellifera.

Science.gov (United States)

Alquisira-Ramírez, Eva Vianey; Peña-Chora, Guadalupe; Hernández-Velázquez, Víctor Manuel; Alvear-García, Andrés; Arenas-Sosa, Iván; Suarez-Rodríguez, Ramón

2017-08-01

The sublethal effects of two strains of Bacillus thuringiensis, which were virulent in vitro to Varroa destructor, were measured on Apis mellifera. The effects of five concentrations of total protein (1, 5, 25, 50 and 100μg/mL) from the EA3 and EA26.1 strains on larval and adult honey bees were evaluated for two and seven days under laboratory conditions. Based on the concentrations evaluated, total protein from the two strains did not affect the development of larvae, the syrup consumption, locomotor activity or proboscis extension response of adults. These same parameters were also tested for the effects of three concentrations (1, 10 and 15μg/kg) of cypermethrin as a positive control. Although no significant differences were observed after two days of treatment with cypermethrin, a dose-response relationship in syrup consumption and locomotor activity was observed. A significant reduction in the proboscis extension response of the bees treated with cypermethrin was also observed. Therefore, in contrast to cypermethrin, our results indicate that the EA3 and EA26.1 strains of B. thuringiensis can be used in beehives to control V. destructor and reduce the negative effects of this mite on colonies without adverse effects on the larvae and adults of A. mellifera. Additionally, the overuse of synthetic miticides, which produce both lethal and sublethal effects on bees, can be reduced. Copyright © 2017 Elsevier Inc. All rights reserved.

Application of the control variate technique to estimation of total sensitivity indices

International Nuclear Information System (INIS)

Kucherenko, S.; Delpuech, B.; Iooss, B.; Tarantola, S.

2015-01-01

Global sensitivity analysis is widely used in many areas of science, biology, sociology and policy planning. The variance-based methods also known as Sobol' sensitivity indices has become the method of choice among practitioners due to its efficiency and ease of interpretation. For complex practical problems, estimation of Sobol' sensitivity indices generally requires a large number of function evaluations to achieve reasonable convergence. To improve the efficiency of the Monte Carlo estimates for the Sobol' total sensitivity indices we apply the control variate reduction technique and develop a new formula for evaluation of total sensitivity indices. Presented results using well known test functions show the efficiency of the developed technique. - Highlights: • We analyse the efficiency of the Monte Carlo estimates of Sobol' sensitivity indices. • The control variate technique is applied for estimation of total sensitivity indices. • We develop a new formula for evaluation of Sobol' total sensitivity indices. • We present test results demonstrating the high efficiency of the developed formula

Bacteriocin-like inhibitory activities of seven Lactobacillus delbrueckii subsp. bulgaricus strains against antibiotic susceptible and resistant Helicobacter pylori strains.

Science.gov (United States)

Boyanova, L; Gergova, G; Markovska, R; Yordanov, D; Mitov, I

2017-12-01

The aim of the study was to detect anti-Helicobacter pylori activity of seven Lactobacillus delbrueckii subsp. bulgaricus (GLB) strains by four cell-free supernatant (CFS) types. Activity of non-neutralized and non-heat-treated (CFSs1), non-neutralized and heat-treated (CFSs2), pH neutralized, catalase-treated and non-heat-treated (CFSs3), or neutralized, catalase- and heat-treated (CFSs4) CFSs against 18 H. pylori strains (11 of which with antibiotic resistance) was evaluated. All GLB strains produced bacteriocin-like inhibitory substances (BLISs), the neutralized CFSs of two GLB strains inhibited >81% of test strains and those of four GLB strains were active against >71% of antibiotic resistant strains. Two H. pylori strains were BLIS resistant. The heating did not reduce the CFS activity. Briefly, all GLB strains evaluated produced heat-stable BLISs, although GLB and H. pylori strain susceptibility patterns exhibited differences. Bacteriocin-like inhibitory substance activity can be an advantage for the probiotic choice for H. pylori infection control. In this study, anti-Helicobacter pylori activity of seven Lactobacillus delbrueckii subsp. bulgaricus (GLB) strains was evaluated by four cell-free supernatant (CFS) types. The GLB strains produced heat-stable bacteriocin-like inhibitory substances (BLISs) with a strong anti-H. pylori activity and some neutralized, catalase- and heat-treated CFSs inhibited >83% of the test strains. Bacteriocin-like inhibitory substance production of GLB strains can render them valuable probiotics in the control of H. pylori infection. © 2017 The Society for Applied Microbiology.

Psychological strains and youth suicide in rural China.

Science.gov (United States)

Zhang, Jie; Wieczorek, William F; Conwell, Yeates; Tu, Xin Ming

2011-06-01

The strain theory of suicide postulates that suicide is usually preceded by psychological strains. A strain can be a consequence of any of four conflicts: differential values, aspiration and reality, relative deprivation, and lack of coping skills for a crisis. This study, with a blend of psychiatric and social predictors of suicide, identified correlates of suicide that are relevant to Chinese culture and tested the strain theory of suicide with Chinese data. We sampled 392 suicides and 416 living controls (both aged 15-34 years) from 16 rural counties in China in 2008 and interviewed two informants for each suicide and each control. We found that marriage and religion/religiosity did not distinguish the suicides from the living controls among Chinese rural young women. Religion/religiosity tended to be stronger for suicides than for controls. Psychological strains in the forms of relative deprivation, unrealized aspiration, and lack of coping skills were significantly associated with suicide, even after accounting for the role of mental illness. The strain theory of suicide forms a challenge to the psychiatric model popular in the West, at least in explaining the Chinese suicide. Copyright © 2011 Elsevier Ltd. All rights reserved.

Predicting a new phase (T'') of two-dimensional transition metal di-chalcogenides and strain-controlled topological phase transition

Science.gov (United States)

Ma, Fengxian; Gao, Guoping; Jiao, Yalong; Gu, Yuantong; Bilic, Ante; Zhang, Haijun; Chen, Zhongfang; Du, Aijun

2016-02-01

Single layered transition metal dichalcogenides have attracted tremendous research interest due to their structural phase diversities. By using a global optimization approach, we have discovered a new phase of transition metal dichalcogenides (labelled as T''), which is confirmed to be energetically, dynamically and kinetically stable by our first-principles calculations. The new T'' MoS2 phase exhibits an intrinsic quantum spin Hall (QSH) effect with a nontrivial gap as large as 0.42 eV, suggesting that a two-dimensional (2D) topological insulator can be achieved at room temperature. Most interestingly, there is a topological phase transition simply driven by a small tensile strain of up to 2%. Furthermore, all the known MX2 (M = Mo or W; X = S, Se or Te) monolayers in the new T'' phase unambiguously display similar band topologies and strain controlled topological phase transitions. Our findings greatly enrich the 2D families of transition metal dichalcogenides and offer a feasible way to control the electronic states of 2D topological insulators for the fabrication of high-speed spintronics devices.Single layered transition metal dichalcogenides have attracted tremendous research interest due to their structural phase diversities. By using a global optimization approach, we have discovered a new phase of transition metal dichalcogenides (labelled as T''), which is confirmed to be energetically, dynamically and kinetically stable by our first-principles calculations. The new T'' MoS2 phase exhibits an intrinsic quantum spin Hall (QSH) effect with a nontrivial gap as large as 0.42 eV, suggesting that a two-dimensional (2D) topological insulator can be achieved at room temperature. Most interestingly, there is a topological phase transition simply driven by a small tensile strain of up to 2%. Furthermore, all the known MX2 (M = Mo or W; X = S, Se or Te) monolayers in the new T'' phase unambiguously display similar band topologies and strain controlled topological

Microstructural evolution of aged heat-resistant cast steel following strain controlled fatigue

International Nuclear Information System (INIS)

Golański, Grzegorz; Zielińska-Lipiec, Anna; Mroziński, Stanisław; Kolan, Cezary

2015-01-01

The paper presents the results of research on the microstructure of high-chromium martensitic GX12CrMoVNbN9-1 (GP91) cast steel after the isothermal ageing process and fatigue process. The fatigue process was performed at room temperature and elevated temperature (600 °C), with the value of total strain amplitude ε ac amounting to 0.25% and 0.60%. Microstructural tests of GP91 cast steel were carried out by means of high-resolution transmission electron microscope. Quantitative study performed by means of TEM included the characteristics of changes in the dislocation substructure and morphology of M 23 C 6 carbides. Performed research has shown that the microstructure of the examined cast steel after ageing is characterized by partly remaining lath microstructure with numerous precipitations of the MX and M 23 C 6 type, as well as the Laves phase. It has been shown that the fatigue test at room temperature contributes to the process of dislocation strengthening of the examined cast steel. The increase of fatigue test temperature influences the degree of increase in the matrix softening. The degree of softening of the cast steel microstructure at elevated temperature depends also on the value of strain amplitude ε ac . The softening process of the examined cast steel was connected with the decrease of dislocation density and increase of subgrains

Evaluation of dry-adapted strains of the predatory mite Neoseiulus californicus for spider mite control on cucumber, strawberry and pepper.

Science.gov (United States)

Palevsky, E; Walzer, A; Gal, S; Schausberger, P

2008-06-01

The goal of this study was to evaluate spider mite control efficacy of two dry-adapted strains of Neoseiulus californicus. Performance of these strains were compared to a commercial strain of Phytoseiulus persimilis on whole cucumber, pepper and strawberry plants infested with Tetranychus urticae at 50 +/- 5% RH. Under these dry conditions predators' performance was very different on each host plant. On cucumber, spider mite suppression was not attained by any of the three predators, plants 'burnt out' within 4 weeks of spider mite infestation. On strawberry, all predators satisfactorily suppressed spider mites yet they differed in short term efficacy and persistence. Phytoseiulus persimilis suppressed the spider mites more rapidly than did the BOKU and SI N. californicus strains. Both N. californicus strains persisted longer than did P. persimilis. The BOKU strain was superior to SI in population density reached, efficacy in spider mite suppression and persistence. On pepper, in the first 2 weeks of the experiment the BOKU strain was similar to P. persimilis and more efficacious in spider mite suppression than strain SI. Four weeks into the experiment the efficacy of P. persimilis dropped dramatically and was inferior to the SI and BOKU strains. Overall, mean predator density was highest on plants harbouring the BOKU strain, lowest on plants with P. persimilis and intermediate on plants with the SI strain. Implications for biocontrol of spider mites using phytoseiid species under dry conditions are discussed.

Controlling charges distribution at the surface of a single GaN nanowire by in-situ strain

Directory of Open Access Journals (Sweden)

Xiao Chen

2017-08-01

Full Text Available Effect of the strain on the charge distribution at the surface of a GaN semiconductor nanowire (NW has been investigated inside transmission electron microscope (TEM by in-situ off-axis electron holography. The outer and inner surfaces of the NW bent axially under compression of two Au electrodes were differently strained, resulting in difference of their Fermi levels. Consequently, the free electrons flow from the high Fermi level to the low level until the two Fermi levels aligned in a line. The potential distributions induced by charge redistribution in the two vacuum sides of the bent NW were examined respectively, and the opposite nature of the bounded charges on the outer and inner surfaces of the bent NW was identified. The results provide experimental evidence that the charge distribution at the surfaces of a single GaN NW can be controlled by different strains created along the NW.

Design and Validation of a Cyclic Strain Bioreactor to Condition Spatially-Selective Scaffolds in Dual Strain Regimes

Directory of Open Access Journals (Sweden)

J. Matthew Goodhart

2014-03-01

Full Text Available The objective of this study was to design and validate a unique bioreactor design for applying spatially selective, linear, cyclic strain to degradable and non-degradable polymeric fabric scaffolds. This system uses a novel three-clamp design to apply cyclic strain via a computer controlled linear actuator to a specified zone of a scaffold while isolating the remainder of the scaffold from strain. Image analysis of polyethylene terephthalate (PET woven scaffolds subjected to a 3% mechanical stretch demonstrated that the stretched portion of the scaffold experienced 2.97% ± 0.13% strain (mean ± standard deviation while the unstretched portion experienced 0.02% ± 0.18% strain. NIH-3T3 fibroblast cells were cultured on the PET scaffolds and half of each scaffold was stretched 5% at 0.5 Hz for one hour per day for 14 days in the bioreactor. Cells were checked for viability and proliferation at the end of the 14 day period and levels of glycosaminoglycan (GAG and collagen (hydroxyproline were measured as indicators of extracellular matrix production. Scaffolds in the bioreactor showed a seven-fold increase in cell number over scaffolds cultured statically in tissue culture plastic petri dishes (control. Bioreactor scaffolds showed a lower concentration of GAG deposition per cell as compared to the control scaffolds largely due to the great increase in cell number. A 75% increase in hydroxyproline concentration per cell was seen in the bioreactor stretched scaffolds as compared to the control scaffolds. Surprisingly, little differences were experienced between the stretched and unstretched portions of the scaffolds for this study. This was largely attributed to the conditioned and shared media effect. Results indicate that the bioreactor system is capable of applying spatially-selective, linear, cyclic strain to cells growing on polymeric fabric scaffolds and evaluating the cellular and matrix responses to the applied strains.

Karna Particle Size Dataset for Tables and Figures

Data.gov (United States)

U.S. Environmental Protection Agency — This dataset contains 1) table of bulk Pb-XAS LCF results, 2) table of bulk As-XAS LCF results, 3) figure data of particle size distribution, and 4) figure data for...

Manual instructivo de instalación y control de prótesis totales Instructive manual of installation and control of total prostheses

Directory of Open Access Journals (Sweden)

Marcia Hortensia Corona Carpio

2007-12-01

Full Text Available Se realizó un estudio de la literatura con el objetivo de describir el paso clínico de instalación y control de prótesis total, durante el período comprendido de enero a mayo del 2005 en la Clínica Estomatológica Provincial Docente de Santiago de Cuba. Se abordaron diversos aspectos, definición de conceptos, así como todo el proceder clínico, instrucciones al paciente y consejo s a los portadores de prótesis. Se enfatizó en el paciente geriátrico, destacándose que precisamente este paso es el indicado para eliminar los defectos evidentes y donde el paciente adquiere el hábito de utilizarlos y el organismo de aceptarlo.A literature study was conducted aimed at describing the clinical step of installation and control of total prosthesis at the Provincial Teaching Dental Clinic of Santiago de Cuba from January to May, 2005. Diverse aspects were dealt with, as well as the definition of concepts, the whole clinical procedure, instructions to the patients and advises to prosthesis wearers. Emphasis was made on the geriatric patient, and it was stressed that this step is the indicated to eliminate the evident defects, and where the patient acquires the habit to use them and the body to accept them.

Microgrid Stability Controller Based on Adaptive Robust Total SMC

Directory of Open Access Journals (Sweden)

Xiaoling Su

2015-03-01

Full Text Available This paper presents a microgrid stability controller (MSC in order to provide existing distributed generation units (DGs the additional functionality of working in islanding mode without changing their control strategies in grid-connected mode and to enhance the stability of the microgrid. Microgrid operating characteristics and mathematical models of the MSC indicate that the system is inherently nonlinear and time-variable. Therefore, this paper proposes an adaptive robust total sliding-mode control (ARTSMC system for the MSC. It is proved that the ARTSMC system is insensitive to parametric uncertainties and external disturbances. The MSC provides fast dynamic response and robustness to the microgrid. When the system is operating in grid-connected mode, it is able to improve the controllability of the exchanged power between the microgrid and the utility grid, while smoothing the DGs’ output power. When the microgrid is operating in islanded mode, it provides voltage and frequency support, while guaranteeing seamless transition between the two operation modes. Simulation and experimental results show the effectiveness of the proposed approach.

Effects of mean strain on the random cyclic stress-strain relations of 0Cr18Ni10Ti pipe steel

International Nuclear Information System (INIS)

Zhao Yongxiang; Yang Bing

2005-01-01

Experimental study is performed for the effects of the mean strain on the random cyclic stress-strain relations of the new nuclear material, 0Cr18Ni10Ti pipe steel. From saving the size of specimens, an improved maximum likelihood fatigue test method is proposed to operate the present strain-controlled fatigue tests. Six straining ratios, -1, -0.52, -0.22, 0.029, 0.18, and 0.48, respectively, are applied to study the effects. Fatigue test has been carried out on totally 104 specimens. The test results reveal that the material exhibits a Masing behaviour and the saturation hysteresis loops under the six ratios hold an entirely relaxation effect of mean stress. There is no effectively method for the description of the mean straining effects under this case. Previous Zhao's random stress-strain relations are therefore applied to characterizing effectively the scattering test data under the six ratios on a basis of Ramberg-Osgood equation. Then the effects of the ratios are analyzed respectively on the average stress amplitudes, the standard deviations of the stress amplitudes, and the stress amplitudes under different survival probabilities and confidences. The results reveal that the ratios act a relatively decreasing effect to the stress amplitudes under higher survival probabilities and confidences. The strongest effect appears at the ratio of 0.029, and a weaker effect acts as the distance increase of the ratio from the zero. In addition, it is indicated that the effects from the sense of average fatigue lives might result in a wrong conclusion. The effects can be appropriately assessed from a probabilistic sense to take into account the scattering regularity of test data and the size of sampling. (author)

The correlation between the ultrasonic elastic strain ratio of thyroid cancer and the malignant biological characteristics of cancer cells in the lesions

Directory of Open Access Journals (Sweden)

Li Ma

2017-04-01

Full Text Available Objective: To study the correlation between the ultrasonic elastic strain ratio of thyroid cancer and the malignant biological characteristics of cancer cells in the lesions. Methods: A total of 90 patients with thyroid cancer who accepted surgical treatment in our hospital between March 2015 and September 2016 were selected as the observation group, and 50 patients who received surgery in our hospital during the same period and were with clear pathological diagnosis of thyroid adenoma were selected as the control group. According to the median of ultrasonic elastic strain ratio, the observing group were further divided into high elastic strain ratio group and low elastic strain ratio group (n=45. RT-PCR was used to determine the mRNA expression of proliferation genes, invasion genes and autophagy genes in lesions of all groups of patients. Results: The mean elastic strain ratio of observation group was significantly lower than that of control group. Proliferation gene FOXA1 mRNA expression in lesions of low elastic strain ratio group and high elastic strain ratio group were higher than those of control group while PP4R1 and Smac mRNA expression were lower than those of control group, and as the elastic strain ratio decreased, the FOXA1 mRNA expression increased while PP4R1 and Smac mRNA expression decreased; invasion genes BCORL1, SATB1, Twist1 and CXCR4 mRNA expression in lesions of low elastic strain ratio group and high elastic strain ratio group were higher than those of control group, and as the elastic strain ratio decreased, the BCORL1, SATB1, Twist1 and CXCR4 mRNA expression increased; autophagy genes ARHI, Beclin1, LC3 and PTEN mRNA expression in lesions of low elastic strain ratio group and high elastic strain ratio group were lower than those of control group, and as the elastic strain ratio decreased, the ARHI, Beclin1, LC3 and PTEN mRNA expression decreased. Conclusion: The ultrasonic elastic strain ratio of thyroid cancer is

Automatic control of the NMB level in general anaesthesia with a switching total system mass control strategy.

Science.gov (United States)

Teixeira, Miguel; Mendonça, Teresa; Rocha, Paula; Rabiço, Rui

2014-12-01

This paper presents a model based switching control strategy to drive the neuromuscular blockade (NMB) level of patients undergoing general anesthesia to a predefined reference. A single-input single-output Wiener system with only two parameters is used to model the effect of two different muscle relaxants, atracurium and rocuronium, and a switching controller is designed based on a bank of total system mass control laws. Each of such laws is tuned for an individual model from a bank chosen to represent the behavior of the whole population. The control law to be applied at each instant corresponds to the model whose NMB response is closer to the patient's response. Moreover a scheme to improve the reference tracking quality based on the analysis of the patient's response, as well as, a comparison between the switching strategy and the Extended Kalman Kilter (EKF) technique are presented. The results are illustrated by means of several simulations, where switching shows to provide good results, both in theory and in practice, with a desirable reference tracking. The reference tracking improvement technique is able to produce a better reference tracking. Also, this technique showed a better performance than the (EKF). Based on these results, the switching control strategy with a bank of total system mass control laws proved to be robust enough to be used as an automatic control system for the NMB level.

Controlling magnetism of MoS2 sheets by embedding transition-metal atoms and applying strain.

Science.gov (United States)

Zhou, Yungang; Su, Qiulei; Wang, Zhiguo; Deng, Huiqiu; Zu, Xiaotao

2013-11-14

Prompted by recent experimental achievement of transition metal (TM) atoms substituted in MoS2 nanostructures during growth or saturating existing vacancies (Sun et al., ACS Nano, 2013, 7, 3506; Deepak et al., J. Am. Chem. Soc., 2007, 129, 12549), we explored, via density functional theory, the magnetic properties of a series of 3d TM atoms substituted in a MoS2 sheet, and found that Mn, Fe, Co, Ni, Cu and Zn substitutions can induce magnetism in the MoS2 sheet. The localizing unpaired 3d electrons of TM atoms respond to the introduction of a magnetic moment. Depending on the species of TM atoms, the substituted MoS2 sheet can be a metal, semiconductor or half-metal. Remarkably, the applied elastic strain can be used to control the strength of the spin-splitting of TM-3d orbitals, leading to an effective manipulation of the magnetism of the TM-substituted MoS2 sheet. We found that the magnetic moment of the Mn- and Fe-substituted MoS2 sheets can monotonously increase with the increase of tensile strain, while the magnetic moment of Co-, Ni-, Cu- and Zn-substituted MoS2 sheets initially increases and then decreases with the increase of tensile strain. An instructive mechanism was proposed to qualitatively explain the variation of magnetism with elastic strain. The finding of the magnetoelastic effect here is technologically important for the fabrication of strain-driven spin devices on MoS2 nanostructures, which allows us to go beyond the current scope limited to the spin devices within graphene and BN-based nanostructures.

On generalization uniaxial stress-strain relation

International Nuclear Information System (INIS)

Sahay, C.; Dubey, R.N.

1980-01-01

Different forms of constitutive relations have been advanced for elastic, plastic and elastic-plastic behaviour of materials. It is shown that the various forms of the stress-strain relationship are specialized forms of generalization of a single stress-strain relation. For example, it is shown how the laws of elastic deformation, and the incremental and total deformation relationship for plastic behaviour are derivable from the Ramberg-Osgood relation. (orig.)

Mechanical control of the electro-optical properties of monolayer and bilayer BC3 by applying the in-plane biaxial strain

Science.gov (United States)

Behzad, Somayeh

2017-11-01

Recently, a new two-dimensional (2D) material, the 2D BC3 crystal, has been synthesized. Here, the mechanical control of the electro-optical properties of monolayer and bilayer BC3 by applying the biaxial strain is investigated. The electronic structure calculations showed that the strain-free monolayer and bilayer BC3 are indirect band-gap semiconductors with band gap of 0.62 and 0.29 eV, respectively, where the conduction band minimum (CBM) is at the M point whereas the valence band maximum (VBM) is at the Γ point. The doubly degenerated bands in the monolayer BC3 are splitted in the bilayer BC3 due to the interlayer interactions. Both monolayer and bilayer BC3 remain indirect gap semiconductor under biaxial tensile strain and their band gaps increases with strain. On the other hand, by increasing the magnitude of tensile strain, the optical spectra shift to the lower energies and the static dielectric constant increases. These findings suggest the potential of strain-engineered 2D BC3 in electronic and optoelectronic device applications.

Strain and strain-release engineering at epitaxial SiGe islands on Si(0 0 1) for microelectronic applications

International Nuclear Information System (INIS)

Vastola, G.; Marzegalli, A.; Montalenti, F.; Miglio, Leo

2009-01-01

We report original finite element method simulations of the strain components at nanometric GeSi island on Si(0 0 1), for realistic shape, sizes and average composition, discussing the main mechanisms acting in the misfit strain relaxation. The tensile strain induced in a 30 nm Si capping layer and the one upon removing the island, after fixing the top part of the Si layer, is discussed in view of application as a field effect transistor channel, with high career mobility induced by the lattice deformation. The large shear components obtained for steeper island morphologies are predicted to be particularly performing, especially in comparison to one another strained-silicon configuration (totally top-down originated), recently developed by IBM corporation.

Mycobacterium tuberculosis strains exhibit differential and strain-specific molecular signatures in pulmonary epithelial cells.

Science.gov (United States)

Mvubu, Nontobeko Eunice; Pillay, Balakrishna; Gamieldien, Junaid; Bishai, William; Pillay, Manormoney

2016-12-01

Although pulmonary epithelial cells are integral to innate and adaptive immune responses during Mycobacterium tuberculosis infection, global transcriptomic changes in these cells remain largely unknown. Changes in gene expression induced in pulmonary epithelial cells infected with M. tuberculosis F15/LAM4/KZN, F11, F28, Beijing and Unique genotypes were investigated by RNA sequencing (RNA-Seq). The Illumina HiSeq 2000 platform generated 50 bp reads that were mapped to the human genome (Hg19) using Tophat (2.0.10). Differential gene expression induced by the different strains in infected relative to the uninfected cells was quantified and compared using Cufflinks (2.1.0) and MeV (4.0.9), respectively. Gene expression varied among the strains with the total number of genes as follows: F15/LAM4/KZN (1187), Beijing (1252), F11 (1639), F28 (870), Unique (886) and H37Rv (1179). A subset of 292 genes was commonly induced by all strains, where 52 genes were down-regulated while 240 genes were up-regulated. Differentially expressed genes were compared among the strains and the number of induced strain-specific gene signatures were as follows: F15/LAM4/KZN (138), Beijing (52), F11 (255), F28 (55), Unique (186) and H37Rv (125). Strain-specific molecular gene signatures associated with functional pathways were observed only for the Unique and H37Rv strains while certain biological functions may be associated with other strain signatures. This study demonstrated that strains of M. tuberculosis induce differential gene expression and strain-specific molecular signatures in pulmonary epithelial cells. Specific signatures induced by clinical strains of M. tuberculosis can be further explored for novel host-associated biomarkers and adjunctive immunotherapies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ultra-Precision Measurement and Control of Angle Motion in Piezo-Based Platforms Using Strain Gauge Sensors and a Robust Composite Controller

Science.gov (United States)

Liu, Lei; Bai, Yu-Guang; Zhang, Da-Li; Wu, Zhi-Gang

2013-01-01

The measurement and control strategy of a piezo-based platform by using strain gauge sensors (SGS) and a robust composite controller is investigated in this paper. First, the experimental setup is constructed by using a piezo-based platform, SGS sensors, an AD5435 platform and two voltage amplifiers. Then, the measurement strategy to measure the tip/tilt angles accurately in the order of sub-μrad is presented. A comprehensive composite control strategy design to enhance the tracking accuracy with a novel driving principle is also proposed. Finally, an experiment is presented to validate the measurement and control strategy. The experimental results demonstrate that the proposed measurement and control strategy provides accurate angle motion with a root mean square (RMS) error of 0.21 μrad, which is approximately equal to the noise level. PMID:23860316

Ultra-Precision Measurement and Control of Angle Motion in Piezo-Based Platforms Using Strain Gauge Sensors and a Robust Composite Controller

Directory of Open Access Journals (Sweden)

Zhi-Gang Wu

2013-07-01

Full Text Available The measurement and control strategy of a piezo-based platform by using strain gauge sensors (SGS and a robust composite controller is investigated in this paper. First, the experimental setup is constructed by using a piezo-based platform, SGS sensors, an AD5435 platform and two voltage amplifiers. Then, the measurement strategy to measure the tip/tilt angles accurately in the order of sub-μrad is presented. A comprehensive composite control strategy design to enhance the tracking accuracy with a novel driving principle is also proposed. Finally, an experiment is presented to validate the measurement and control strategy. The experimental results demonstrate that the proposed measurement and control strategy provides accurate angle motion with a root mean square (RMS error of 0.21 μrad, which is approximately equal to the noise level.

Porosity Assessment for Different Diameters of Coir Lignocellulosic Fibers

Science.gov (United States)

da Luz, Fernanda Santos; Paciornik, Sidnei; Monteiro, Sergio Neves; da Silva, Luiz Carlos; Tommasini, Flávio James; Candido, Verônica Scarpini

2017-10-01

The application of natural lignocellulosic fibers (LCFs) in engineering composites has increased interest in their properties and structural characteristics. In particular, the inherent porosity of an LCF markedly affects its density and the adhesion to polymer matrices. For the first time, both open and closed porosities of a natural LCF, for different diameter ranges, were assessed. Fibers extracted from the mesocarp of the coconut fruit were investigated by nondestructive methods of density measurements and x-ray microtomography (microCT). It was found that, for all diameter ranges, the closed porosity is significantly higher than the open porosity. The total porosity increases with diameter to around 60% for coir fibers with more than 503 μm in diameter. The amount and characteristics of these open and closed porosities were revealed by t test and Weibull statistics as well as by microCT.

Segregation of genes from donor strain during the production of recombinant congenic strains.

Science.gov (United States)

van Zutphen, L F; Den Bieman, M; Lankhorst, A; Demant, P

1991-07-01

Recombinant congenic strains (RCS) constitute a set of inbred strains which are designed to dissect the genetic control of multigenic traits, such as tumour susceptibility or disease resistance. Each RCS contains a small fraction of the genome of a common donor strain, while the majority of genes stem from a common background strain. We tested at two stages of the inbreeding process in 20 RCS, derived from BALB/cHeA and STS/A, to see whether alleles from the STS/A donor strain are distributed over the RCS in a ratio as would theoretically be expected. Four marker genes (Pep-3; Pgm-1; Gpi-1 and Es-3) located at 4 different chromosomes were selected and the allelic distribution was tested after 3-4 and after 12 generations of inbreeding. The data obtained do not significantly deviate from the expected pattern, thus supporting the validity of the concept of RCS.

Anaplasma marginale major surface protein 1a: a marker of strain diversity with implications for control of bovine anaplasmosis.

Science.gov (United States)

Cabezas-Cruz, Alejandro; de la Fuente, José

2015-04-01

Classification of bacteria is challenging due to the lack of a theory-based framework. In addition, the adaptation of bacteria to ecological niches often results in selection of strains with diverse virulence, pathogenicity and transmission characteristics. Bacterial strain diversity presents challenges for taxonomic classification, which in turn impacts the ability to develop accurate diagnostics and effective vaccines. Over the past decade, the worldwide diversity of Anaplasma marginale, an economically important tick-borne pathogen of cattle, has become apparent. The extent of A. marginale strain diversity, formerly underappreciated, has contributed to the challenges of classification which, in turn, likely impacts the design and development of improved vaccines. Notably, the A. marginale surface protein 1a (MSP1a) is a model molecule for these studies because it serves as a marker for strain identity, is both an adhesin necessary for infection of cells and an immuno-reactive protein and is also an indicator of the evolution of strain diversity. Herein, we discuss a molecular taxonomic approach for classification of A. marginale strain diversity. Taxonomic analysis of this important molecule provides the opportunity to understand A. marginale strain diversity as it relates geographic and ecological factors and to the development of effective vaccines for control of bovine anaplasmosis worldwide. Copyright © 2015 Elsevier GmbH. All rights reserved.

Graphene spin diode: Strain-modulated spin rectification

Energy Technology Data Exchange (ETDEWEB)

Wang, Yunhua; Wang, B., E-mail: stslyl@mail.sysu.edu.cn, E-mail: wangbiao@mail.sysu.edu.cn [Sino-French Institute of Nuclear Engineering and Technology, School of Physics and Engineering, State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275 (China); Liu, Yulan, E-mail: stslyl@mail.sysu.edu.cn, E-mail: wangbiao@mail.sysu.edu.cn [School of Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

2014-08-04

Strain effects on spin transport in a ferromagnetic/strained/normal graphene junction are explored theoretically. It is shown that the spin-resolved Fermi energy range can be controlled by the armchair direction strain because the strain-induced pseudomagnetic field suppresses the current. The spin rectification effect for the bias reversal occurs because of a combination of ferromagnetic exchange splitting and the broken spatial symmetry of the junction. In addition, the spin rectification performance can be tuned remarkably by manipulation of the strains. In view of this strain-modulated spin rectification effect, we propose that the graphene-based ferromagnetic/strained/normal junction can be used as a tunable spin diode.

Electric-field control of magnetism via strain transfer across ferromagnetic/ferroelectric interfaces.

Science.gov (United States)

Taniyama, Tomoyasu

2015-12-23

By taking advantage of the coupling between magnetism and ferroelectricity, ferromagnetic (FM)/ferroelectric (FE) multiferroic interfaces play a pivotal role in manipulating magnetism by electric fields. Integrating the multiferroic heterostructures into spintronic devices significantly reduces energy dissipation from Joule heating because only an electric field is required to switch the magnetic element. New concepts of storage and processing of information thus can be envisioned when the electric-field control of magnetism is a viable alternative to the traditional current based means of controlling magnetism. This article reviews some salient aspects of the electric-field effects on magnetism, providing a short overview of the mechanisms of magneto-electric (ME) coupling at the FM/FE interfaces. A particular emphasis is placed on the ME effect via interfacial magneto-elastic coupling arising from strain transfer from the FE to FM layer. Recent results that demonstrate the electric-field control of magnetic anisotropy, magnetic order, magnetic domain wall motion, and etc are described. Obstacles that need to be overcome are also discussed for making this a reality for future device applications.

Electric-field control of magnetism via strain transfer across ferromagnetic/ferroelectric interfaces

International Nuclear Information System (INIS)

Taniyama, Tomoyasu

2015-01-01

By taking advantage of the coupling between magnetism and ferroelectricity, ferromagnetic (FM)/ferroelectric (FE) multiferroic interfaces play a pivotal role in manipulating magnetism by electric fields. Integrating the multiferroic heterostructures into spintronic devices significantly reduces energy dissipation from Joule heating because only an electric field is required to switch the magnetic element. New concepts of storage and processing of information thus can be envisioned when the electric-field control of magnetism is a viable alternative to the traditional current based means of controlling magnetism. This article reviews some salient aspects of the electric-field effects on magnetism, providing a short overview of the mechanisms of magneto-electric (ME) coupling at the FM/FE interfaces. A particular emphasis is placed on the ME effect via interfacial magneto-elastic coupling arising from strain transfer from the FE to FM layer. Recent results that demonstrate the electric-field control of magnetic anisotropy, magnetic order, magnetic domain wall motion, and etc are described. Obstacles that need to be overcome are also discussed for making this a reality for future device applications. (topical review)

[Characteristics of natural strains of naphthalene-utilizing bacteria of the genus Pseudomonas].

Science.gov (United States)

Levchuk, A A; Vasilenko, S L; Bulyga, I M; Titok, M A; Thomas, K M

2005-01-01

Sixty-three strains of bacteria capable of utilizing naphthalene as the sole source of carbon and energy were isolated from 137 samples of soil taken in different sites in Belarus. All isolated bacteria contained extrachromosomal genetic elements of 45 to 150 kb in length. It was found that bacteria of 31 strains contained the IncP-9 incompatibility group plasmids, bacteria of one strain carried a plasmid containing replicons IncP-9 and IncP-7, and bacteria of 31 strains contained unidentified plasmids. Primary identification showed that the hosts of plasmids of naphthalene biodegradation are fluorescent bacteria of the genus Pseudomonas (P. putida and P. aeruginosa; a total of 47 strains) and unidentified nonfluorescent microorganisms (a total of 16 strains). In addition to the ability to utilize naphthalene, some strains exhibited the ability to stimulate the growth and development of the root system of Secale cereale.

Strain engineering of van der Waals heterostructures

NARCIS (Netherlands)

Vermeulen, Paul A.; Mulder, Jefta; Momand, Jamo; Kooi, Bart J.

2018-01-01

Modifying the strain state of solids allows control over a plethora of functional properties. The weak interlayer bonding in van der Waals (vdWaals) materials such as graphene, hBN, MoS2, and Bi2Te3 might seem to exclude strain engineering, since strain would immediately relax at the vdWaals

Oxide-assisted crack growth in hold-time low-cycle-fatigue of single-crystal superalloys

Directory of Open Access Journals (Sweden)

Suzuki Akane

2014-01-01

Full Text Available Compressive hold-time low-cycle fatigue is one of the important damage modes in Ni-based superalloy hot-gas path components. In strain controlled LCF, the compressive hold typically degrades fatigue life significantly due to creep relaxation and the resultant generation of tensile stress upon returning to zero strain. Crack initiation typically occurs on the surface, and therefore, the cracks are covered with layers of oxides. Recent finite element modeling based on experimental observations has indicated that the in-plane compressive stress in the alumina layer formed on the surface of the bond coat assists rumpling and, eventually, leads to initiation of cracks. The stress in the oxide layer continues to assist crack extension by pushing the alumina layer along the crack front during the compressive hold. In-situ measurements of the growth strains of alumina were performed using high energy synchrotron X-rays at Argonne National Lab. Specimens of single-crystal superalloys with and without aluminide coatings were statically pre-oxidized to form a layer of alumina at 1093 and 982 ∘C. For the in-situ synchrotron measurements, the specimens were heated up to the pre-oxidation temperatures with a heater. The alumina layers on both bare and coated specimens show compressive in-plane strains at both temperatures. The oxide strains on the superalloys showed dependency on temperature; on the other hand, the oxide strains in the aluminide coatings were insensitive to temperature. The magnitude of the compressive strains was larger on the superalloys than the ones on the aluminide coatings.

Investigation of bending fatigue-life of aluminum sheets based on rolling direction

Directory of Open Access Journals (Sweden)

Raif Sakin

2018-03-01

Full Text Available High-cycle fatigue (HCF and low-cycle fatigue (LCF fatigue lives of rolled AA1100 and AA1050 aluminum sheets along different directions were evaluated at room temperature. Four types of samples denoted as longitudinal (L and transverse (T to the rolling direction were compared because the samples along the two typical directions show an obvious anisotropy. A cantilever plane-bending and multi-type fatigue testing machine was specially designed for this purpose. Deflection-controlled fatigue tests were conducted under fully reversed loading. The longest fatigue lives in the LCF region were obtained for AA1050 (L while AA1100 (L samples had the longest fatigue lives in the HCF region. Keywords: AA1100, AA1050, Aluminum sheet, Bending fatigue life, Rolling direction

Enhancing water stress tolerance improves fitness in biological control strains of Lactobacillus plantarum in plant environments.

Science.gov (United States)

Daranas, Núria; Badosa, Esther; Francés, Jesús; Montesinos, Emilio; Bonaterra, Anna

2018-01-01

Lactobacillus plantarum strains PM411 and TC92 can efficiently control bacterial plant diseases, but their fitness on the plant surface is limited under unfavourable low relative humidity (RH) conditions. To increase tolerance of these strains to water stress, an adaptive strategy was used consisting of hyperosmotic and acidic conditions during growth. Adapted cells had higher survival rates under desiccation than non-adapted cells. Transcript levels and patterns of general stress-related genes increased immediately after the combined-stress adaptation treatment, and remained unaltered or repressed during the desiccation challenge. However, there were differences between strains in the transcription patterns that were in agreement with a better performance of adapted cells of PM411 than TC92 in plant surfaces under low RH environmental conditions. The combined-stress adaptation treatment increased the survival of PM411 cells consistently in different plant hosts in the greenhouse and under field conditions. Stress-adapted cells of PM411 had similar biocontrol potential against bacterial plant pathogens than non-adapted cells, but with less variability within experiments.

Enhancing water stress tolerance improves fitness in biological control strains of Lactobacillus plantarum in plant environments.

Directory of Open Access Journals (Sweden)

Núria Daranas

Full Text Available Lactobacillus plantarum strains PM411 and TC92 can efficiently control bacterial plant diseases, but their fitness on the plant surface is limited under unfavourable low relative humidity (RH conditions. To increase tolerance of these strains to water stress, an adaptive strategy was used consisting of hyperosmotic and acidic conditions during growth. Adapted cells had higher survival rates under desiccation than non-adapted cells. Transcript levels and patterns of general stress-related genes increased immediately after the combined-stress adaptation treatment, and remained unaltered or repressed during the desiccation challenge. However, there were differences between strains in the transcription patterns that were in agreement with a better performance of adapted cells of PM411 than TC92 in plant surfaces under low RH environmental conditions. The combined-stress adaptation treatment increased the survival of PM411 cells consistently in different plant hosts in the greenhouse and under field conditions. Stress-adapted cells of PM411 had similar biocontrol potential against bacterial plant pathogens than non-adapted cells, but with less variability within experiments.

Screening and characterization of Lactobacillus strains producing large amounts of exopolysaccharides

NARCIS (Netherlands)

Geel-Schutten, G.H. van; Flesch, F.; Brink, B. ten; Smith, M.R.; Dijkhuizen, L.

1998-01-01

A total of 182 Lactobacillus strains were screened for production of extracellular polysaccharides (EPS) by a new method: growth in liquid media with high sugar concentrations. Sixty EPS-positive strains were identified; 17 strains produced more than 100 mg/l soluble EPS. Sucrose was an excellent

Selection, application and monitoring of Lactobacillus paracasei strains as adjunct cultures in the production of Gouda-type cheeses.

Science.gov (United States)

Van Hoorde, Koenraad; Van Leuven, Isabelle; Dirinck, Patrick; Heyndrickx, Marc; Coudijzer, Kathleen; Vandamme, Peter; Huys, Geert

2010-12-15

Raw milk cheeses have more intense flavours than cheeses made from pasteurized milk and harbour strains with potential adjunct properties. Two Lactobacillus paracasei strains, R-40926 and R-40937, were selected as potential adjunct cultures from a total of 734 isolates from good quality artisan raw milk Gouda-type cheeses on the basis of their prevalence in different cheese types and/or over several production batches, safety and technological parameters. Conventional culturing, isolation and identification and a combined PCR-DGGE approach using total cheese DNA extracts and DNA extracts obtained from culturable fractions were employed to monitor viability of the introduced adjuncts and their effect on the cheese microbiota. The control cheese made without adjuncts was dominated by members of the starter, i.e. Lactococcus lactis and Leuconostoc pseudomesenteroides. In the cheeses containing either R-40926 or R-40937, the respective adjuncts increased in number as ripening progressed indicating that both strains are well adapted to the cheese environment and can survive in a competitive environment in the presence of a commercial starter culture. Principal component analysis of cheese volatiles determined by steam distillation-extraction and gas chromatography-mass spectrometry could differentiate cheeses made with different concentrations of adjunct R-40926 from the control cheese, and these differences could be correlated to the proteolytic and lipolytic properties of this strain. Collectively, results from microbiological and metabolic analyses indicate that the screening procedure followed throughout this study was successful in delivering potential adjunct candidates to enrich or extend the flavour palette of artisan Gouda-type cheeses under more controlled conditions. Copyright © 2010 Elsevier B.V. All rights reserved.

Strain modification on electronic transport of the phosphorene nanoribbon

Directory of Open Access Journals (Sweden)

Yawen Yuan

2017-07-01

Full Text Available We demonstrate theoretically how local strains can be tailored to control quantum transport of carriers on monolayer armchair and zigzag phosphorene nanoribbon. We find that the electron tunneling is forbidden when the in-plane strain exceeds a critical value. The critical strain is different for different crystal orientation of the ribbons, widths, and incident energies. By tuning the Fermi energy and strain, the channels can be transited from opaque to transparent. Moreover, for the zigzag-phosphorene nanoribbon, the two-fold degenerate quasi-flat edge band splits completely under certain strain. These properties provide us an efficient way to control the transport of monolayer phosphorene-based microstructure.

Serum total proteins and creatinine levels in experimental gambian ...

African Journals Online (AJOL)

Attempt was therefore made to evaluate the effect of two strains of Trypanosoma brucei gambiense on total proteins and other serum biochemical parameters using vervet monkeys as a model. The outcome of both strains in vervet monkeys was traumatic as the monkeys died from infection 12 – 15 weeks post infection while ...

Control of hole localization in magnetic semiconductors by axial strain

Science.gov (United States)

Raebiger, Hannes; Bae, Soungmin; Echeverría-Arrondo, Carlos; Ayuela, Andrés

2018-02-01

Mn and Fe-doped GaN are widely studied prototype systems for hole-mediated magnetic semiconductors. The nature of the hole states around the Mn and Fe impurities, however, remains under debate. Our self-interaction corrected density-functional calculations show that the charge neutral Mn 0 and positively charged Fe+ impurities have symmetry-broken d5+h ground states, in which the hole is trapped by one of the surrounding N atoms in a small polaron state. We further show that both systems also have a variety of other d5+h configurations, including symmetric, delocalized states, which may be stabilized by axial strain. This finding opens a pathway to promote long-range hole-mediated magnetic interactions by strain engineering and clarifies why highly strained thin-films samples often exhibit anomalous magnetic properties.

Linhagens de Trichogramma e Trichogrammatoidea para controle de Stenoma catenifer Trichogramma and Trichogrammatoidea strains to control Stenoma catenifer

Directory of Open Access Journals (Sweden)

Dori Edson Nava

2007-01-01

Full Text Available O objetivo deste trabalho foi selecionar espécies e linhagens de Trichogramma e Trichogrammatoidea, com potencial para controle da broca-do-abacate Stenoma catenifer, considerada a principal praga do abacateiro (Persea americana Mill.. Experimentos em laboratório foram realizados com 12 linhagens das seguintes espécies, sendo: oito de Trichogramma pretiosum; uma de Trichogramma atopovirilia; duas de Trichogramma bruni; e uma de Trichogrammatoidea annulata. Em telado, determinou-se o número de parasitóides a ser liberado por ovo de S. catenifer. Os parâmetros biológicos avaliados em laboratório foram: duração do período ovo-adulto, emergência, parasitismo, razão sexual, número de parasitóides emergidos por ovo de S. catenifer e longevidade de fêmeas e machos. Em telado, avaliou-se o número de ovos parasitados. As espécies Trichogrammatoidea annulata e Trichogramma atopovirilia e suas linhagens foram selecionadas por parasitar maior número de ovos de S. catenifer. Nessas condições, o maior parasitismo foi obtido com uma proporção estimada de 28 e 30 parasitóides, por ovo da praga, respectivamente, para Trichogrammatoidea annulata e Trichogramma atopovirilia.The objective of this work was to select Trichogramma and Trichogrammatoidea species and strains with potential to control the avocado fruit borer Stenoma catenifer, considered the main avocado (Persea americana Mill. pest. Laboratory experiments were carried out with the following strains and species, which comprised eight Trichogramma pretiosum; one Trichogramma atopovirilia; two Trichogramma bruni; and one Trichogrammatoidea annulata. The number of parasitoids to be released per S. catenifer egg under semi-field conditions was studied. Biological parameters evaluated in laboratory were egg-adult development time, survivorship, parasitism, sex ratio, number of parasitoids emerged per S. catenifer egg, and adult longevity. In semi-field experiment, the number of

Research of angelica sinensis (Oliv) diels new strain DGA2000-02 selection

International Nuclear Information System (INIS)

Xie Hongmei; Li Wenjian; Hao Jifang; Liu Jing; Liu Xiaorui; Jing Yanming; Shang Hushan; Liu Rongqing; He Baogang; Wang Chunming; Zhang Guoli; Chen Shuzhen

2008-01-01

Angelica sinensis(Oliv)Diets new strain DGA2000-02 was selected successfully by Institute of Modern Physics, Chinese Academy of Sciences, Dryland Farming Research and Extension Center of Dingxi Prefecture, etc. According to the program of new strain selection, this new strain was selected for several year's after the dry seeds of Gansu Angelica sinensis(Oliv)Diels 90-01 was irradiated by ions of 55 MeV/u 40 Ar +15 . During the period of year 2005-2007, region experiments of Angelica sinensis (Oliv)Diels new strain DGA2000-02 were developed in Minxian, Weiyuan, Zhangxian and Longxi etc. Average yield of the fresh DGA2000-02 Angelica was 10 621.5 kg/hm 2 , and 15.0% production was increased more than control (for 1 386.0 kg/hm 2 of 90-01). The growth stage of the DGA2000-02 was 790 d, and it has deep purple stem and yellow-white root. The quality analysis results are as follows: total ash content is 4.2% and acidast ash content is 0.4%, 16% and 33.3% better than control, respectively; the lixivium is 61.4%, i.e., 4.4% more than the standard of Pharmacopoeia of People's Republic of China (2005 edition); the ferullc acid content is 0.148%, i.e., 2.96 times ligher than the standard. All these results showed that the quality of the DGA2000-02 was better significantly than both control and the standard. It can be grown appropriately at the high, cold and dankness regions at the altitude of 2000-2600 m and with a annual precipitation of 500-600 mm. (authors)

Heterogenic control groups in randomized, controlled, analgesic trials of total hip and knee arthroplasty.

Science.gov (United States)

Karlsen, Anders P; Mathiesen, Ole; Dahl, Jørgen B

2018-03-01

Postoperative analgesic interventions are often tested adjunct to basic non-opioid analgesics in randomized controlled trials (RCTs). Consequently, treatment in control groups, and possible assay sensitivity, differs between trials. We hypothesized that postoperative opioid requirements and pain intensities vary between different control groups in analgesic trials. Control groups from RCTs investigating analgesic interventions after total hip and knee arthroplasty were categorized based on standardized basic analgesic treatment. Morphine consumption 0 to 24 hours postoperatively, and resting pain scores at 6 and 24 hours for subgroups of basic treatments, were compared with ANOVA. In an additional analysis, we compared pain and opioid requirements in trials where a non-steroidal anti-inflammatory drug (NSAID) was administered as an intervention with trial where NSAID was administered in a control group. We included 171 RCTs employing 28 different control groups with large variability in pain scores and opioid requirements. Four types of control groups (comprising 78 trials) were eligible for subgroup comparisons. These subgroups received "opioid" alone, "NSAID + opioid", "acetaminophen + opioid", or "NSAID + acetaminophen + opioid", respectively. Morphine consumption and pain scores varied substantially between these groups, with no consistent superior efficacy in any subgroup. Additionally, trials administering NSAID as an intervention demonstrated lower pain scores and opioid requirements than trials where NSAID was administered in a control group. Analgesic treatment in RCT control groups varies considerably. Control groups receiving various combinations of opioid, NSAID and acetaminophen did not differ consistently in pain and opioid requirements. Pain and opioid requirements were lower in trials administering NSAID as an intervention compared with trials administering NSAID in a control group.

Effects of C and Si on strain aging of strain-based API X60 pipeline steels

Science.gov (United States)

Sung, Hyo Kyung; Lee, Dong Ho; Lee, Sunghak; Lee, Byeong-Joo; Hong, Seung-Pyo; Kim, Young-Woon; Yoo, Jang Yong; Hwang, Byoungchul; Shin, Sang Yong

2017-05-01

Four types of strain-based API X60 pipeline steels were fabricated by varying the C and Si contents, and the effects of C and Si on strain aging were investigated. The 0.05 wt% C steels consisted mainly of polygonal ferrite (PF), whereas the 0.08 wt% C steels consisted of acicular ferrite (AF). The volume fraction of AF increased with increasing C content because C is an austenite stabilizer element. The volume fractions of bainitic ferrite (BF) of the 0.15 wt% Si steels were higher than those of the 0.25 wt% Si steels, whereas the volume fractions of the secondary phases were lower. From the tensile properties before and after the aging process of the strainbased API X60 pipeline steels, the yield strength increased and the uniform and total elongation decreased, which is the strain aging effect. The strain aging effect in the strain-based API X60 pipeline steels was minimized when the volume fraction of AF was increased and secondary phases were distributed uniformly. On the other hand, an excessively high C content formed fine precipitates, and the strain aging effect occurred because of the interactions among dislocations and fine precipitates.

Job strain and time to pregnancy

DEFF Research Database (Denmark)

Hjollund, N H; Kold Jensen, T; Bonde, Jens Peter

1998-01-01

The association between fertility and job strain defined as high job demands and low job control has not previously been studied. A follow-up study was conducted with prospective collection of information on job strain among women, achievement of pregnancy, and potential confounding variables....

Rhizobium Strain Effects on Yield and Bleeding Sap Amino Compounds in Pisum sativum

DEFF Research Database (Denmark)

Rosendahl, Lis

1984-01-01

Bleeding sap composition, dry matter production and N distribution in pea (P. sativum L. cv. Bodil) grown with and without nitrate and nodulated with either R. leguminosarum strain 128c53 or strain 1044 were compared. Nitrate increased the total dry matter production of both symbioses, but decrea......Bleeding sap composition, dry matter production and N distribution in pea (P. sativum L. cv. Bodil) grown with and without nitrate and nodulated with either R. leguminosarum strain 128c53 or strain 1044 were compared. Nitrate increased the total dry matter production of both symbioses...... relative to the total N-accumulation was greater with strain 128c53 due to a higher production of nodule tissue. The root bleeding sap of the symbiosis with the greater yield (strain 1044) contained high levels of asparagine and aspartic acid. In the 128c53 symbiosis, glutamine plus homoserine accounted...... for a higher percentage of the organic solutes transporting newly assimilated N from the root system than in the association with 1044. The Rhizobium strain effect on amino compound composition of the bleeding sap may indicate an influence of the bacteroids on either the N-assimilatory enzyme system...

Morphogenesis and Biomechanics of Engineered Skin Cultured Under Uniaxial Strain.

Science.gov (United States)

Blackstone, Britani N; Powell, Heather M

2012-04-01

Split-thickness autograft is the standard wound treatment for full-thickness burns. In large burns, sparse availability of uninjured skin prevents rapid closure of the wound, resulting in increased scar tissue formation or mortality. Tissue-engineered skin (ES) offers promise when autografts are not available. ES, constructed from a polymeric scaffold and skin cells, has been shown to reduce donor site area required to permanently close wounds, mortality, and morbidity from scarring but cannot restore all skin functions. Current generations of ES are orders of magnitude weaker than normal human skin, leading to difficulty in surgical application, greater susceptibility to mechanical damage during fabrication and application, and less elasticity and strength once engrafted. Previous studies to improve ES biomechanics focus on altering the scaffolding material, which resulted in modest improvements but often inhibited proper skin development. As the skin is naturally under static strain, adding these mechanical cues to the culture environment is hypothesized to improve ES biomechanics. ES was cultured under applied static strains ranging from 0% to 40% strain for a total of 10 days. Strain magnitudes of 10% and 20% strain resulted in significantly stronger ES than unstrained controls, showed upregulation of many genes encoding structural extracellular matrix proteins, and exhibited increased epidermal cell proliferation and differentiation. Enhanced biomechanical properties of ES can allow for facile surgical application and less damage during dressing changes. These findings suggest that mechanical cues play a significant role in skin development and should be further explored.

Microstructural aspects of crack formation and propagation in the austenitic steel X6CrNiNb18-10 under low cycle fatigue loading

International Nuclear Information System (INIS)

Soppa, E.; Kohler, C.; Roos, E.; Schuler, X.

2012-01-01

The understanding of the crack initiation mechanisms and crack growth in apparently monolithic materials like X6CrNiNb18-10 stainless steel under cyclic loading requires the explicit analysis of the phenomena underlying fatigue on both atomistic and microscopic levels. The permanent delivery of mechanical energy through cyclic loading evokes changes in the microstructure that can lead to a martensitic transformation. The transformation of a metastable cubic face centered austenite and formation of a cubic body centered α'-martensite under cyclic loading at room temperature was found, both, in the experiment and in molecular dynamics simulations. The martensite nucleates prevalently at grain boundaries, triple points and at the specimen free surface and forms small (∝ 1 μm) differently oriented grains, also in the same parent austenitic grain. By a combination of interrupted low cycle fatigue tests (LCF) and electron backscatter diffraction (EBSD) measurements the martensitic transformation and subsequent fatigue crack formation were observed at the same area in the microstructure at different stages of the specimen lifetime. The EBSD measurements showed the following crack initiation scenarios: Cracks started (a) at the phase boundary between austenite and α'-martensite, (b) inside fully martensitic areas in the matrix, (c) at broken or debonded coarse NbCs. It is obvious that formation of a hard α'-martensite in a ductile and soft austenite and forming two-phase material causes a heterogeneous stress and strain distribution on the microscopic level. α'-martensite enhances locally the stress amplitude whereas in a soft austenite the plastic strain amplitude increases. Strain concentration in the austenite along the phase boundary is connected with a stress increase along the interface and can initiate fatigue crack there. Also at the crack tip, a permanent martensitic transformation occurs, so that the growth of the fatigue cracks at room temperature seems

Molecular and biochemical studies of some yeast strains

African Journals Online (AJOL)

user

2011-02-21

Feb 21, 2011 ... Kluyveromyces lactis (Y.9) and Pichia jadinii (Y.10) contained almost double the amount of total amino ... Differences between ... biochemical analysis (total protein profile and total amino acids) were used as tools to select the best yeast strains in Saudi Arabia and Egypt as a rich source of animal protein.

Evidence for three types of x-ray damage repair in yeast and sensitivity of totally repair deficient strains to sunlight

International Nuclear Information System (INIS)

Game, J.C.; Schild, D.; Mortimer, R.K.

1987-01-01

Mutants of yeast that confer sensitivity to x-rays are known to fall into two epistasis groups, called here the RAD51 and RAD18 groups, which are each thought to control a different type of x-ray repair. They examine here the role of genes in a third repair pathways in x-ray repair. RAD1 and RAD3 are known to be important in the repair of pyrimidine dimers after uv-irradiation. They find that these genes can also play an important role in x-ray repair, but that this role is only exposed when both the other pathways of x-ray repair are blocked. Double mutants blocked in the RAD51 and RAD18 pathways are significantly less x-ray sensitive than triple mutants blocked in these pathways but also mutant in either the RAD1 or RAD3 genes. In a related experiment, they tested the importance of DNA repair in nature by determining the sensitivity to natural unfiltered sunlight of a strain lacking all known DNA repair pathways. They constructed a quadruple mutant strain containing RAD1-1, RAD18-2, RAD51-1 and PHR1-1. The latter mutation blocks the cell's ability to photoreactivate uv damage. They found that this strain was so sensitive to sunlight that less than three seconds' exposure would cause an average of one lethal hit per cell, and survival was less than 2% after ten seconds' exposure. Wild type yeast at sea level showed no killing after thirty minutes. the quadruple mutant is approximately one thousand times more sensitive to sunlight than the related wild type

STRAIN-CONTROLLED BIAXIAL TENSION OF NATURAL RUBBER: NEW EXPERIMENTAL DATA

KAUST Repository

Pancheri, Francesco Q.

2014-03-01

We present a new experimental method and provide data showing the response of 40A natural rubber in uniaxial, pure shear, and biaxial tension. Real-time biaxial strain control allows for independent and automatic variation of the velocity of extension and retraction of each actuator to maintain the preselected deformation rate within the gage area of the specimen. Wealso focus on the Valanis-Landel hypothesis that is used to verify and validate the consistency of the data.Weuse a threeterm Ogden model to derive stress-stretch relations to validate the experimental data. The material model parameters are determined using the primary loading path in uniaxial and equibiaxial tension. Excellent agreement is found when the model is used to predict the response in biaxial tension for different maximum in-plane stretches. The application of the Valanis-Landel hypothesis also results in excellent agreement with the theoretical prediction.

Effectiveness of Bupivacaine Liposome Injectable Suspension for Postoperative Pain Control in Total Knee Arthroplasty: A Prospective, Randomized, Double Blind, Controlled Study.

Science.gov (United States)

DeClaire, Jeffrey H; Aiello, Paige M; Warritay, Olayinka K; Freeman, Dwight C

2017-09-01

We compared the effectiveness of liposomal bupivacaine to ropivacaine, each as part of multimodal pain management, in total knee arthroplasty (TKA) postoperative pain control. This prospective, double blind study randomized 96 TKA patients into a control group (periarticular injection of ropivacaine, ketorolac, morphine, and epinephrine in saline; 100cc) or an experimental group (periarticular injection of bupivacaine, ketorolac, morphine, and epinephrine in saline; 80cc plus 1.3% liposomal bupivacaine 20cc; total injection 100cc). The postoperative use of narcotics, visual analog pain scores, hours to ambulate 100 feet, and length of hospital stay were recorded. There was no significant difference between the two groups (control N = 49, experiment N = 47) in mean narcotic use per hour, total narcotic use during hospital stay, time to ambulate 100 feet, length of hospital stay, or visual analog score for pain postoperatively. There is no benefit in the use of liposomal bupivacaine compared with ropivacaine for postoperative pain control in TKA. Copyright © 2017 Elsevier Inc. All rights reserved.

Molecular, morphological and pathogenic characterization of six strains of Metarhizium spp. (Deuteromycotina: Hyphomycetes for the control of Aegorhinus superciliosus (Coleoptera: Curculionidae

Directory of Open Access Journals (Sweden)

María Sepúlveda

2016-03-01

Full Text Available Aegorhinus superciliosus is an important pest on blueberry (Vaccinium corymbosum L. and other fruit trees. The use of entomopathogenic fungi as Metarhizium spp. has been evaluated for the control of this insect, but variability has been observed among different strains. The aim of this study was to characterize six promising strains of Metarhizium spp. for the control of A. superciliosus. The studied strains were QuM173c, Qu-M363, Qu-M171a, Qu-M156a, Qu-M421, and Qu-M430, all of which belonged to the Chilean Collection of Microbial Genetic Resources (ChCMGR of the Institute de Investigaciones Agropecuarias (INIA, Chile. Molecular characterization was made by sequencing the ITS region (Internal Transcribed Spacers, ITS-5.8S rDNA. The morphology of conidia was evaluated through scanning electron microscopy and radial colony growth was evaluated in potato dextrose agar (PDA, Sabouraud dextrose agar (SDA, agar enriched with larvae of Galleria mellonella (Lepidoptera: Pyralidae (GA, and agar enriched with adults of A. superciliosus (AA. Pathogenicity was studied based on mortality of adults of A. superciliosus inoculated with conidia. Sequencing of the ITS-5.8S rDNA region indicates that the strains belong to the clade of M. anisopliae var. anisopliae, except for Qu-M171a, which was identified as M. anisopliae var. lepidiotum. Conidia average length for the six strains was 5.09 pm and average conidia width was 1.92 pm. Radial colony growth differences were observed between strains (p < 0.01 and between different growth media (p < 0.01. The strains exhibited the highest colony growth in the GA medium, while in the AA medium they showed the lowest (p < 0.01. Pathogenicity tests show that Qu-M430 reached a 90% mortality rate (p < 0.01. Results show that there is variability between the studied strains, which is expressed in their morphology, molecular characteristics and pathogenicity towards A. superciliosus.

Automatic Strain-Rate Controller,

Science.gov (United States)

1976-12-01

D—AO37 9~e2 ROME AIR DEVELOPMENT CENTER GRIFFISS AFB N 1’ FIG 13/ 6AUTOMATIC STRAIN—RATE CONTROLLER, (U) DEC 76 R L HUNTSINGER. J A ADAMSK I...goes to zero. CONTROLLER, Leeds and Northrup Series 80 CAT with proportional band , rate , reset, and approach controls . Input from deviation output...8) through ( 16) . (8) Move the set-point slowl y up to 3 or 4. (9) If the recorder po inter hunts , adjust the func t ion controls on tine Ser

Adhesion activity of glyceraldehyde-3-phosphate dehydrogenase in a Chinese Streptococcus suis type 2 strain.

Science.gov (United States)

Wang, Kaicheng; Lu, Chengping

2007-01-01

A total of 36 streptococcal strains, including seven S. equi ssp.zooepidemicus, two S. suis type 1 (SS1), 24 SS2, two SS9, and one SS7, were tested for glyceraldehyde-3-phosphate dehydrogenase gene (gapdh). Except from non-virulent SS2 strain T1 5, all strains harboured gapdh. The gapdh of Chinese Sichuan SS2 isolate ZY05719 and Jiangsu SS2 isolate HA9801 were sequenced and then compared with published sequences in the GenBank. The comparison revealed a 99.9 % and 99.8 % similarity of ZY05719 and HA9801, respectively, with the published sequence. Adherence assay data demonstrated a significant ((p<0.05)) reduction in adhesion of SS2 in HEp-2 cells pre-incubated with purified GAPDH compared to non pre-incubated controls, suggesting the GAPDH mediates SS2 bacterial adhesion to host cells.

Cyclic plastic material behavior leading to crack initiation in stainless steel under complex fatigue loading conditions

International Nuclear Information System (INIS)

Facheris, G.

2014-01-01

The improvement of the reliability and of the safety in the design of components belonging to the primary cooling circuit of a light water nuclear reactor is nowadays one of the most important research topics in nuclear industry. One of the most important damage mechanisms leading the crack initiation in this class of components is the low cycle fatigue (LCF) driven by thermal strain fluctuations caused by the complex thermo-mechanical loading conditions typical for the primary circuit (e.g. operating thermal transients, thermal stratification, turbulent mixing of cold and hot water flows, etc.). The cyclic application of the resulting plastic deformation to the steel grades commonly used for the fabrication of piping parts (e.g. austenitic stainless steels) is associated with a continuous evolution of the mechanical response of the material. As an additional complication, the cyclic behavior of stainless steels is influenced by temperature, strain amplitude and cyclic accumulation of inelastic strain (i.e. ratcheting). The accurate prediction of the structural response of components belonging to the primary cooling circuit requires the development of a reliable constitutive model that must be characterized by a reduced complexity to allow its application in an industrial context. In this framework, the main goal of the current dissertation is to formulate, calibrate and implement in a commercial Finite Element code, a constitutive model that is suitable for the stainless stain grade 316L subjected to complex loading conditions. As a first task, a characterization of the mechanical behavior of 316L subjected to uniaxial and multiaxial strain-controlled conditions (including LCF and ratcheting) is carried out performing several tests in the laboratories of the Paul Scherrer Institute (PSI, Villigen, Switzerland) and of Politecnico di Milano (Italy). The uniaxial experiments demonstrate that, prescribing a strain-controlled ratcheting path, a harder material response

Cyclic plastic material behavior leading to crack initiation in stainless steel under complex fatigue loading conditions

Energy Technology Data Exchange (ETDEWEB)

Facheris, G.

2014-07-01

The improvement of the reliability and of the safety in the design of components belonging to the primary cooling circuit of a light water nuclear reactor is nowadays one of the most important research topics in nuclear industry. One of the most important damage mechanisms leading the crack initiation in this class of components is the low cycle fatigue (LCF) driven by thermal strain fluctuations caused by the complex thermo-mechanical loading conditions typical for the primary circuit (e.g. operating thermal transients, thermal stratification, turbulent mixing of cold and hot water flows, etc.). The cyclic application of the resulting plastic deformation to the steel grades commonly used for the fabrication of piping parts (e.g. austenitic stainless steels) is associated with a continuous evolution of the mechanical response of the material. As an additional complication, the cyclic behavior of stainless steels is influenced by temperature, strain amplitude and cyclic accumulation of inelastic strain (i.e. ratcheting). The accurate prediction of the structural response of components belonging to the primary cooling circuit requires the development of a reliable constitutive model that must be characterized by a reduced complexity to allow its application in an industrial context. In this framework, the main goal of the current dissertation is to formulate, calibrate and implement in a commercial Finite Element code, a constitutive model that is suitable for the stainless stain grade 316L subjected to complex loading conditions. As a first task, a characterization of the mechanical behavior of 316L subjected to uniaxial and multiaxial strain-controlled conditions (including LCF and ratcheting) is carried out performing several tests in the laboratories of the Paul Scherrer Institute (PSI, Villigen, Switzerland) and of Politecnico di Milano (Italy). The uniaxial experiments demonstrate that, prescribing a strain-controlled ratcheting path, a harder material response

Production traits of broiler chicken strains fed Ad Libitum and raised ...

African Journals Online (AJOL)

... of commercial broiler chickens reared on full-feeding, and under the same housing, feeding regime, agro-climatic zone and management practices. A total number of 150 broiler dayold chicks, that, is 50 chicks each of Arbor Acres (strain A), Hubbard (strain B) and Marshall (strain C) were purchased from local hatcheries, ...

[Subjective job strain and job satisfaction among neurologists in German hospitals].

Science.gov (United States)

Bauer, J; Bendels, M H K; Groneberg, D A

2016-06-01

The number of sick leaves due to job strain is increasing. This study's scope is to examine working conditions of neurologists in hospitals in regard to job strain and job satisfaction. This study is part of the iCEPT-Study. The iCEPT-Study was conducted as a web based survey among physicians (n = 7090) in German hospitals. The focus was on working conditions regarding job strain. Job strain was measured by a questionnaire consisting of items and scales from the short version of the Effort-Reward-Imbalance (ERI) questionnaire and the short questionnaire for working analysis (KFZA). By calculation ratios of distinct scales according to validated stress models a conclusion could be drawn as to whether or not job strain was present. The total number of n = 354 neurologists were analyzed. The response rate was at 18.2 %. Job strain was encountered by 52.0 % (95 %-KI: 46.7|57.2) of all neurologists and no significant gender difference was present. However, resident neurologists were significantly more often exposed to job strain than attending neurologists (OR = 2.9; 95 %-KI: 1.6-4.7; p job satisfaction, 59.6 % (95 %-KI: 54.5-64.7) of all respondents stated to be satisfied with their job. Significantly more men were satisfied than women (OR = 1.5; 95 %-KI: 1.0-2.4; p job than residents (OR = 2.9; 95 %-KI: 1.7-4.8; p job strain among neurologists in German hospitals. Keeping the negative implications of mental and physical health in mind, the working conditions of neurologists must be improved. As shown in this study, a possible way to do so is to increase job control in order to decrease a major stressor at work.

Study on the total amount control of atmospheric pollutant based on GIS.

Science.gov (United States)

Wang, Jian-Ping; Guo, Xi-Kun

2005-08-01

To provide effective environmental management for total amount control of atmospheric pollutants. An atmospheric diffusion model of sulfur dioxide on the surface of the earth was established and tested in Shantou of Guangdong Province on the basis of an overall assessment of regional natural environment, social economic state of development, pollution sources and atmospheric environmental quality. Compared with actual monitoring results in a studied region, simulation values fell within the range of two times of error and were evenly distributed in the two sides of the monitored values. Predicted with the largest emission model method, the largest emission of sulfur dioxide would be 54,279.792 tons per year in 2010. The mathematical model established and revised on the basis of GIS is more rational and suitable for the regional characteristics of total amount control of air pollutants.

Functional and hypoglycemic properties of nopal cladodes (O. ficus-indica) at different maturity stages using in vitro and in vivo tests.

Science.gov (United States)

Nuñez-López, María A; Paredes-López, Octavio; Reynoso-Camacho, Rosalía

2013-11-20

Nopal (Opuntia ficus-indica) cladodes are recommended for their therapeutic properties; their maturity stage may affect their biological properties. Cladodes of three maturity stages, from the same crop and location, were dehydrated and evaluated for some of their physicochemical and nutritional characteristics and antidiabetic properties. The flours of small and medium cladodes (SCF and MCF, respectively) had higher contents of dietary fiber, water absorption, swelling, and viscosity compared to those of the large cladode flour (LCF). Streptozotocin-induced diabetic rats, treated with MCF and SCF (doses of 50 mg/kg body weight), showed reduction of postprandial blood glucose on 46.0 and 23.6%, respectively (p < 0.05), in relation to the control; and LCF had no significant effect. In vitro, glucose diffusion tests showed similar ranking by the two former samples, whereas the latter was close to the control. Cladode maturity stages showed different fiber content and produced suspensions with differences in viscosity, which may affect in vitro and in vivo glucose responses.

Influence of pores on crack initiation in monotonic tensile and cyclic loadings in lost foam casting A319 alloy by using 3D in-situ analysis

International Nuclear Information System (INIS)

Wang, Long; Limodin, Nathalie; El Bartali, Ahmed; Witz, Jean-François; Seghir, Rian; Buffiere, Jean-Yves; Charkaluk, Eric

2016-01-01

Lost Foam Casting (LFC) process is replacing the conventional gravity Die Casting (DC) process in automotive industry for the purpose of geometry optimization, cost reduction and consumption control. However, due to lower cooling rate, LFC produces in a coarser microstructure that reduces fatigue life. In order to study the influence of the casting microstructure of LFC Al-Si alloy on damage micromechanisms under monotonic tensile loading and Low Cycle Fatigue (LCF) at room temperature, an experimental protocol based on the three dimensional (3D) in-situ analysis has been set up and validated. This paper focuses on the influence of pores on crack initiation in monotonic and cyclic tensile loadings. X-ray Computed Tomography (CT) allowed the microstructure of material being characterized in 3D and damage evolution being followed in-situ also in 3D. Experimental and numerical mechanical fields were obtained by using Digital Volume Correlation (DVC) technique and Finite Element Method (FEM) simulation respectively. Pores were shown to have an important influence on strain localization as large pores generate enough strain localization zones for crack initiation both in monotonic tensile and cyclic loadings.

Influence of pores on crack initiation in monotonic tensile and cyclic loadings in lost foam casting A319 alloy by using 3D in-situ analysis

Energy Technology Data Exchange (ETDEWEB)

Wang, Long, E-mail: longwang_calt@163.com [Univ. Lille, CNRS, Centrale Lille, Arts et Metiers Paris tech, FRE 3723 – LML – Laboratoire de Mecanique de Lille, F-59000 Lille (France); Limodin, Nathalie; El Bartali, Ahmed; Witz, Jean-François; Seghir, Rian [Univ. Lille, CNRS, Centrale Lille, Arts et Metiers Paris tech, FRE 3723 – LML – Laboratoire de Mecanique de Lille, F-59000 Lille (France); Buffiere, Jean-Yves [Laboratoire Matériaux, Ingénierie et Sciences (MATEIS), CNRS UMR5510, INSA-Lyon, 20 Av. Albert Einstein, 69621 Villeurbanne (France); Charkaluk, Eric [Univ. Lille, CNRS, Centrale Lille, Arts et Metiers Paris tech, FRE 3723 – LML – Laboratoire de Mecanique de Lille, F-59000 Lille (France)

2016-09-15

Lost Foam Casting (LFC) process is replacing the conventional gravity Die Casting (DC) process in automotive industry for the purpose of geometry optimization, cost reduction and consumption control. However, due to lower cooling rate, LFC produces in a coarser microstructure that reduces fatigue life. In order to study the influence of the casting microstructure of LFC Al-Si alloy on damage micromechanisms under monotonic tensile loading and Low Cycle Fatigue (LCF) at room temperature, an experimental protocol based on the three dimensional (3D) in-situ analysis has been set up and validated. This paper focuses on the influence of pores on crack initiation in monotonic and cyclic tensile loadings. X-ray Computed Tomography (CT) allowed the microstructure of material being characterized in 3D and damage evolution being followed in-situ also in 3D. Experimental and numerical mechanical fields were obtained by using Digital Volume Correlation (DVC) technique and Finite Element Method (FEM) simulation respectively. Pores were shown to have an important influence on strain localization as large pores generate enough strain localization zones for crack initiation both in monotonic tensile and cyclic loadings.

Strain localization and elastic-plastic coupling during deformation of porous sandstone

Energy Technology Data Exchange (ETDEWEB)

Dewers, Thomas A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Geomechanics Dept.; Issen, Kathleen A. [Clarkson Univ., Potsdam, NY (United States). Mechanical and Aeronautical Engineering; Holcomb, David J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Geomechanics Dept.; Olsson, William A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Geomechanics Dept.; Ingraham, Mathew D. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Geomechanics Dept.

2017-09-12

Results of axisymmetric compression tests on weak, porous Castlegate Sandstone (Cretaceous, Utah, USA), covering a range of dilational and compactional behaviors, are examined for localization behavior. Assuming isotropy, bulk and shear moduli evolve as increasing functions of mean stress and Mises equivalent shear stress respectively, and as decreasing functions of work-conjugate plastic strains. Acoustic emissions events located during testing show onset of localization and permit calculation of observed shear and low-angle compaction localization zones, or bands, as localization commences. Total strain measured experimentally partitions into: A) elastic strain with constant moduli, B) elastic strain due to stress dependence of moduli, C) elastic strain due to moduli degradation with increasing plastic strain, and D) plastic strain. The third term is the elastic-plastic coupling strain, and though often ignored, contributes significantly to pre-failure total strain for brittle and transitional tests. Constitutive parameters and localization predictions derived from experiments are compared to theoretical predictions. In the brittle regime, predictions of band angles (angle between band normal and maximum compression) demonstrate good agreement with observed shear band angles. Compaction localization was observed in the transitional regime in between shear localization and spatially pervasive compaction, over a small range of mean stresses. In contrast with predictions however, detailed acoustic emissions analyses in this regime show low angle, compaction-dominated but shear-enhanced, localization.

Effect of Indigenous Pseudomonas sp. and Bacillus sp. Strains on Yield and Main Chemical Growth Parameters of Radicchio

Directory of Open Access Journals (Sweden)

Stanojković-Sebić Aleksandra

2018-03-01

Full Text Available Pseudomonas sp. and Bacillus sp. belong to plant growth promoting rhizobacteria which are able to colonize the plants roots and stimulate growth. In this study, the effect of two indigenous plant growth promoting rhizobacterial strains Pseudomonas sp. Q4 and Bacillus sp. Q10 and their mixture (mix Q4+Q10 on content of the main chemical growth parameters (nitrogen, phosphorus, potassium, calcium and magnesium and the yield of dry biomass of radicchio (Cichorium spp. var. rossa di treviso aerial parts and root, was investigated. The study was carried out with stagnosol type of soil in pot experiments under semi-controlled conditions in the Institute of Soil Science (Belgrade, in the period from July to October in 2013. Phosphorus was determined by spectrophotometer, potassium - by flame emission photometry and total nitrogen and carbon - using elemental CNS analyzer, while calcium and magnesium were determined by AAS. The data on yield of both aerial parts and root dry biomass of radicchio showed that its treatment with Q4 and Q10 strains, as well as with their mixture, caused noticeably increase in this parameter in relation to the control, whereby the strain Q4 was more effective for aerial parts, while mix Q4+Q10 - for roots. The obtained data on the studied chemical parameters of radicchio root and aerial parts were in total accordance with their yield. Concluding, studied strains have a potential in promoting the biomass yield and main chemical growth parameters of both aerial parts and root of radicchio.

Proposta do uso de pool de sangue total como controle interno de qualidade em hematologia

OpenAIRE

Schons,Carina Daniele; Tavares,Rejane Giacomelli

2010-01-01

INTRODUÇÃO: A confiabilidade dos resultados do laboratório é garantida pela realização do controle de qualidade, que tem como funções básicas análise, pesquisa e prevenção da ocorrência de erros laboratoriais por meio de programas que abrangem tanto o controle interno quanto o externo. OBJETIVO: Propor a padronização de utilização de pool de sangue total como controle interno de qualidade no setor de hematologia. MÉTODO: Foram selecionadas amostras de sangue total, colhidas com ácido etilenod...

The radiographic observation of the cervical strain

International Nuclear Information System (INIS)

Rhee, Chung Sik

1972-01-01

A total of 100 cases of cervical disorders were analysed of clinical signs and symptoms. The cervical strain is proved by the loss of normal lordotic curvature of the cervical spinal column on the lateral x-ray film in Ewha University Hospital from January, 1970 to december 1971 with the following results. 1. The 53 cervical strain was diagnosed in radiographic study for its abnormal locations. The hyperextension with abnormal curve is twice more after than hyperflection type. 2. The most frequent location of the cervical strain is demonstrated in the 4-6 th cervical spinal bodies (80%). 3. Most pronounced symptoms of cervical strain are local tenderness (40%), limitation of motion (17%) and radiating pain (15%). 4. The ratio of the sex incidence of male female was 3:2

The radiographic observation of the cervical strain

Energy Technology Data Exchange (ETDEWEB)

Rhee, Chung Sik [Ewha Womans University College of Medicine, Seoul (Korea, Republic of)

1972-12-15

A total of 100 cases of cervical disorders were analysed of clinical signs and symptoms. The cervical strain is proved by the loss of normal lordotic curvature of the cervical spinal column on the lateral x-ray film in Ewha University Hospital from January, 1970 to december 1971 with the following results. 1. The 53 cervical strain was diagnosed in radiographic study for its abnormal locations. The hyperextension with abnormal curve is twice more after than hyperflection type. 2. The most frequent location of the cervical strain is demonstrated in the 4-6 th cervical spinal bodies (80%). 3. Most pronounced symptoms of cervical strain are local tenderness (40%), limitation of motion (17%) and radiating pain (15%). 4. The ratio of the sex incidence of male female was 3:2.

Genetic control of the radiosensitivity of lymphoid cells for antibody-forming ability in CXS series of recombinant inbred mouse strains

International Nuclear Information System (INIS)

Okumoto, M.; Mori, N.; Nishikawa, R.; Imai, S.; Hilgers, J.; Takamori, Y.; Yagasaki, O.

1992-01-01

Incidence of radiation-induced lymphomas differs remarkably among various mouse strains. BALB/cHeA (C) mice are highly susceptible to radiation induction of lymphomas, while STS/A (S) mice are resistant. Thus, the induction of the disease is controlled by some genetic factors. To examine an involvement of radiosensitivity of lymphoid cells in lymphomagenesis, we have compared genetic control of the radiosensitivity for antibody-forming ability with that of lymphoma development in BALB/cHeA, STS/A, (CXS)F 1 hybrids and CXS series of recombinant inbred strains. Decrease of number of splenic plaque-forming cell (PFC) in Jerne's method by 3 Gy of X-irradiation for BALB/cHeA mice was larger than that for STS/A mice by more than one order of magnitude. (CXS)F 1 hybrid mice showed small number of decrease of PFC similar to STS/A mice suggesting that phenotype of radioresistance was dominant over sensitivity. The best concordance between genetic markers and radiosensitivities of antibody-forming ability in recombinant inbred strains was observed in a region containing Igh locus on chromosome 12. The results show that one locus controlling the radioresistance of lymphoid cells for antibody-forming ability might exist in the region containing Igh locus, and that this region clearly differ from a region with Ifa locus on chromosome 4 which regulate the susceptibility to radiation-induced lymphomagenesis. (author)

Differential effects of two strains of Rhizophagus intraradices on dry biomass and essential oil yield and composition in Calamintha nepeta

Directory of Open Access Journals (Sweden)

Roxana P Colombo

Full Text Available The aim of this work was to determine the effects of two geographically different strains of Rhizophagus intraradices (M3 and GA5 on the total biomass and essential oil (EO yield and composition of Calamintha nepeta, with or without phosphorus (P fertilization, under greenhouse conditions.The plant biomass was not significantly affected by any of the treatments, showing higher values in control plants. Strains had a differential response in their root colonization rates: M3 reduced these parameters while GA5 did not modify them. Both strains affected EO yield in absence of P fertilization: M3 promoted EO yield in C. nepeta plants and GA5 resulted in negative effects. The percentage composition of EO was not significantly modified by either strain or P fertilization. M3 strain could be a potential fungal bioinoculant for production and commercialization of C. nepeta in the aromatic plant market.

Probiotic properties of Lactobacillus strains isolated from Tibetan kefir grains.

Directory of Open Access Journals (Sweden)

Yongchen Zheng

Full Text Available The objective of this study was to evaluate the functional properties of lactic acid bacteria (LAB isolated from Tibetan kefir grains. Three Lactobacillus isolates identified as Lactobacillus acidophilus LA15, Lactobacillus plantarum B23 and Lactobacillus kefiri D17 that showed resistance to acid and bile salts were selected for further evaluation of their probiotic properties. The 3 selected strains expressed high in vitro adherence to Caco-2 cells. They were sensitive to gentamicin, erythromycin and chloramphenicol and resistant to vancomycin with MIC values of 26 µg/ml. All 3 strains showed potential bile salt hydrolase (BSH activity, cholesterol assimilation and cholesterol co-precipitation ability. Additionally, the potential effect of these strains on plasma cholesterol levels was evaluated in Sprague-Dawley (SD rats. Rats in 4 treatment groups were fed the following experimental diets for 4 weeks: a high-cholesterol diet, a high-cholesterol diet plus LA15, a high-cholesterol diet plus B23 or a high-cholesterol diet plus D17. The total cholesterol, triglyceride and low-density lipoprotein cholesterol levels in the serum were significantly (P<0.05 decreased in the LAB-treated rats compared with rats fed a high-cholesterol diet without LAB supplementation. The high-density lipoprotein cholesterol levels in groups B23 and D17 were significantly (P<0.05 higher than those in the control and LA15 groups. Additionally, both fecal cholesterol and bile acid levels were significantly (P<0.05 increased after LAB administration. Fecal lactobacilli counts were significantly (P<0.05 higher in the LAB treatment groups than in the control groups. Furthermore, the 3 strains were detected in the rat small intestine, colon and feces during the feeding trial. The bacteria levels remained high even after the LAB administration had been stopped for 2 weeks. These results suggest that these strains may be used in the future as probiotic starter cultures for

Probiotic Properties of Lactobacillus Strains Isolated from Tibetan Kefir Grains

Science.gov (United States)

Zheng, Yongchen; Lu, Yingli; Wang, Jinfeng; Yang, Longfei; Pan, Chenyu; Huang, Ying

2013-01-01

The objective of this study was to evaluate the functional properties of lactic acid bacteria (LAB) isolated from Tibetan kefir grains. Three Lactobacillus isolates identified as Lactobacillus acidophilus LA15, Lactobacillus plantarum B23 and Lactobacillus kefiri D17 that showed resistance to acid and bile salts were selected for further evaluation of their probiotic properties. The 3 selected strains expressed high in vitro adherence to Caco-2 cells. They were sensitive to gentamicin, erythromycin and chloramphenicol and resistant to vancomycin with MIC values of 26 µg/ml. All 3 strains showed potential bile salt hydrolase (BSH) activity, cholesterol assimilation and cholesterol co-precipitation ability. Additionally, the potential effect of these strains on plasma cholesterol levels was evaluated in Sprague-Dawley (SD) rats. Rats in 4 treatment groups were fed the following experimental diets for 4 weeks: a high-cholesterol diet, a high-cholesterol diet plus LA15, a high-cholesterol diet plus B23 or a high-cholesterol diet plus D17. The total cholesterol, triglyceride and low-density lipoprotein cholesterol levels in the serum were significantly (P<0.05) decreased in the LAB-treated rats compared with rats fed a high-cholesterol diet without LAB supplementation. The high-density lipoprotein cholesterol levels in groups B23 and D17 were significantly (P<0.05) higher than those in the control and LA15 groups. Additionally, both fecal cholesterol and bile acid levels were significantly (P<0.05) increased after LAB administration. Fecal lactobacilli counts were significantly (P<0.05) higher in the LAB treatment groups than in the control groups. Furthermore, the 3 strains were detected in the rat small intestine, colon and feces during the feeding trial. The bacteria levels remained high even after the LAB administration had been stopped for 2 weeks. These results suggest that these strains may be used in the future as probiotic starter cultures for manufacturing

The Cyclic Stress-Strain Curve of Polycrystals

DEFF Research Database (Denmark)

Pedersen, Ole Bøcker; Rasmussen, K. V.; Winter, A. T.

1982-01-01

The internal stresses implied by the Sachs model are estimated for individual PSBs at low plastic strain amplitudes and for homogeneously sheared grains at higher plastic strain amplitudes. The analysis shows that the Sachs model can account semi-quantitatively for experimentally measured cyclic...... stress-strain curves for copper. A similar approximative analysis of the Taylor model cannot account for the data. An interesting feature of the Sachs model is that, although it is assumed that the flow condition is entirely controlled by the PSBs. the predicted cyclic stress-strain curve displays...

Time related total lactic acid bacteria population diversity and ...

African Journals Online (AJOL)

The total lactic acid bacterial community involved in the spontaneous fermentation of malted cowpea fortified cereal weaning food was investigated by phenotypically and cultivation independent method. A total of 74 out of the isolated 178 strains were Lactobacillus plantarum, 32 were Pediococcus acidilactici and over 60% ...

A rapid cycleave PCR method for distinguishing the vaccine strain Brucella abortus A19 in China.

Science.gov (United States)

Nan, Wenlong; Zhang, Yueyong; Tan, Pengfei; Xu, Zouliang; Chen, Yuqi; Mao, Kairong; Chen, Yiping

2016-05-01

Brucellosis is a widespread zoonotic disease caused by Brucella spp. Immunization with attenuated vaccines has proved to be an effective method of prevention; however, it may also interfere with diagnosis. Brucella abortus strain A19, which is homologous to B. abortus strain S19, is widely used for the prevention of bovine brucellosis in China. For effective monitoring of the control of brucellosis, it is essential to distinguish A19 from field strains. Single-nucleotide polymorphism-based assays offer a new approach to such discrimination studies. In the current study, we developed a cycleave PCR assay that successfully distinguished attenuated vaccine strains A19 and S19 from 22 strains of B. abortus and 57 strains of 5 other Brucella species. The assay gave a negative reaction with 4 non-Brucella species. The minimum sensitivity of the assay, evaluated using 10-fold dilutions of chromosomal DNA, was 7.6 fg for the A19 strain and 220 fg for the single non-A19/non-S19 Brucella strain tested (B. abortus 104M). The assay was also reproducible (intra- and interassay coefficients of variation: 0.003-0.01 and 0.004-0.025, respectively). The cycleave assay gave an A19/S19-specific reaction in 3 out of 125 field serum samples, with the same 3 samples being positive in an alternative A19/S19-specific molecular assay. The cycleave assay gave a total of 102 Brucella-specific reactions (3 being the A19/S19-specific reactions), whereas an alternative Brucella-specific assay gave 92 positive reactions (all also positive in the cycleave assay). Therefore, this assay represents a simple, rapid, sensitive, and specific tool for use in brucellosis control. © 2016 The Author(s).

A randomised, controlled trial of circumpatellar electrocautery in total knee replacement without patellar resurfacing.

Science.gov (United States)

van Jonbergen, H P W; Scholtes, V A B; van Kampen, A; Poolman, R W

2011-08-01

The efficacy of circumpatellar electrocautery in reducing the incidence of post-operative anterior knee pain is unknown. We conducted a single-centre, outcome-assessor and patient-blinded, parallel-group, randomised, controlled trial to compare circumpatellar electrocautery with no electrocautery in total knee replacement in the absence of patellar resurfacing. Patients requiring knee replacement for primary osteoarthritis were randomly assigned circumpatellar electrocautery (intervention group) or no electrocautery (control group). The primary outcome measure was the incidence of anterior knee pain. A secondary measure was the standardised clinical and patient-reported outcomes determined by the American Knee Society scores and the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index. A total of 131 knees received circumpatellar electrocautery and 131 had no electrocautery. The overall incidence of anterior knee pain at follow-up at one year was 26% (20% to 31%), with 19% (12% to 26%) in the intervention group and 32% (24% to 40%) in the control group (p = 0.02). The relative risk reduction from electrocautery was 40% (9% to 61%) and the number needed to treat was 7.7 (4.3 to 41.4). The intervention group had a better mean total WOMAC score at follow-up at one year compared with the control group (16.3 (0 to 77.7) versus 21.6 (0 to 76.7), p = 0.04). The mean post-operative American Knee Society knee scores and function scores were similar in the intervention and control groups (knee score: 92.4 (55 to 100) versus 90.4 (51 to 100), respectively (p = 0.14); function score: 86.5 (15 to 100) versus 84.5 (30 to 100), respectively (p = 0.49)). Our study suggests that in the absence of patellar resurfacing electrocautery around the margin of the patella improves the outcome of total knee replacement.

Assessment of intra-species diversity among strains of Acinetobacter baumannii isolated from sites contaminated with petroleum hydrocarbons

International Nuclear Information System (INIS)

Manab Sarma, P.; Bhattacharya, D.; Krishnan, S.; Lal, B.

2004-01-01

Intra-species diversity among Acinetobacter baumannii strains isolated from crude oil-contaminated soils from different geographic regions in India was assessed, including their capability to degrade different fractions of total petroleum hydrocarbons. A total of 96 strains were isolated from five different sites. Of the 96 isolates, 25 strains were identified as Acinetobacter baumannii; all of these strains were biochemically profiled and grouped into eight phenovars on the basis of multivariate analysis of their substrate utilization profiles. All strains were able to degrade the total petroleum hydrocarbon fractions of crude oil. Intraspecies relatedness among the 25 strains was determined using tRNA intergenic spacer length polymorphism. Specific variants among the strains with different degradation capacities for different fractions of crude oil were detected. Environmental influences that cause intra-species diversity, such as functional resilience, within the selected strains of A. baumannii were also noted. It is suggested that such diversities may make it possible to select contaminant-specific strains for efficient biotechnological strategies in environmental remediation. 19 refs., 4 tabs., 3 figs

Assessment of intra-species diversity among strains of Acinetobacter baumannii isolated from sites contaminated with petroleum hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Manab Sarma, P.; Bhattacharya, D.; Krishnan, S. [TERI School of Advanced Studies, Center of Bioresources and Biotechnology, New Delhi (India); Lal, B. [TERI School of Advanced Studies, Microbial Biotechnology Division, New Delhi (India)

2004-06-01

Intra-species diversity among Acinetobacter baumannii strains isolated from crude oil-contaminated soils from different geographic regions in India was assessed, including their capability to degrade different fractions of total petroleum hydrocarbons. A total of 96 strains were isolated from five different sites. Of the 96 isolates, 25 strains were identified as Acinetobacter baumannii; all of these strains were biochemically profiled and grouped into eight phenovars on the basis of multivariate analysis of their substrate utilization profiles. All strains were able to degrade the total petroleum hydrocarbon fractions of crude oil. Intraspecies relatedness among the 25 strains was determined using tRNA intergenic spacer length polymorphism. Specific variants among the strains with different degradation capacities for different fractions of crude oil were detected. Environmental influences that cause intra-species diversity, such as functional resilience, within the selected strains of A. baumannii were also noted. It is suggested that such diversities may make it possible to select contaminant-specific strains for efficient biotechnological strategies in environmental remediation. 19 refs., 4 tabs., 3 figs.

Twenty-eight divergent polysaccharide loci specifying within and amongst strain capsule diversity in three strains of Bacteroides fragilis

DEFF Research Database (Denmark)

Patrick, S.; Blakely, G.W.; Houston, S.

2010-01-01

including a putative Wzx flippase and Wzy polymerase, was confirmed in all three strains, despite a lack of cross-reactivity between NCTC 9343 and 638R surface polysaccharide-specific antibodies by immunolabelling and microscopy. Genomic comparisons revealed an exceptional level of polysaccharide...... biosynthesis locus diversity. Of the 10 divergent polysaccharide associated loci apparent in each strain, none are similar between NCTC9343 and 638R. YCH46 shares one locus with NCTC9343, confirmed by MAb labelling, and a second different locus with 638R, making a total of 28 divergent polysaccharide...... restriction and modification systems that act to prevent acquisition of foreign DNA. The level of amongst strain diversity in polysaccharide biosynthesis loci is unprecedented....

Ethanol fermentation from lignocellulosic hydrolysate by a recombinant xylose- and cellooligosaccharide-assimilating yeast strain

Energy Technology Data Exchange (ETDEWEB)

Katahira, Satoshi; Fukuda, Hideki [Kobe Univ. (Japan). Div. of Molecular Science; Mizuike, Atsuko; Kondo, Akihiko [Kobe Univ. (Japan). Dept. of Chemical Science and Engineering

2006-10-15

The sulfuric acid hydrolysate of lignocellulosic biomass, such as wood chips, from the forest industry is an important material for fuel bioethanol production. In this study, we constructed a recombinant yeast strain that can ferment xylose and cellooligosaccharides by integrating genes for the intercellular expressions of xylose reductase and xylitol dehydrogenase from Pichia stipitis, and xylulokinase from Saccharomyces cerevisiae and a gene for displaying ss-glucosidase from Aspergillus acleatus on the cell surface. In the fermentation of the sulfuric acid hydrolysate of wood chips, xylose and cellooligosaccharides were completely fermented after 36 h by the recombinant strain, and then about 30 g/l ethanol was produced from 73 g/l total sugar added at the beginning. In this case, the ethanol yield of this recombinant yeast was much higher than that of the control yeast. These results demonstrate that the fermentation of the lignocellulose hydrolysate is performed efficiently by the recombinant Saccharomyces strain with abilities for xylose assimilation and cellooligosaccharide degradation. (orig.)

Informal eldercare and work-related strain.

Science.gov (United States)

Trukeschitz, Birgit; Schneider, Ulrike; Mühlmann, Richard; Ponocny, Ivo

2013-03-01

In light of an aging workforce, reconciling informal eldercare and paid work becomes increasingly pertinent. This article investigates the association between informal eldercare and work-related strain and tests for both the "competing demands" and "expansion" hypotheses. The sample of 938 Austrian employees consisted of employees caring for older relatives and a control group of employees without eldercare obligations. We ran a Tobit regression model on work-related strain with different measures of informal eldercare as explanatory variables and controls for both personal and workplace characteristics. Accounting for different characteristics of eldercare within one estimation model revealed that informal eldercare was associated with work-related strain in 2 ways, that is, it increased with both care hours and subjective care burden. However, after controlling for these burdensome attributes of eldercare, the carer status as such was found to be negatively associated with work-related strain. In addition and independently of care commitments, work-related factors, such as advanced skills and job motivation, reduced work-related strain. This article lends support to both the "competing demands" and the "expansion" hypotheses. Commitment to eldercare can enhance work-related outcomes but entails work-related problems if care burden and time demands of eldercare are substantial. Thus, workers with eldercare responsibilities cannot be considered less productive from the outset. An individual assessment of their situation, considering the care and work setting, is required. Findings from this study support the design of workplace initiatives to uphold workers' productivity in general and bring specific attention to policies alleviating workers' eldercare burden.

Thermoelastoviscoplastic modeling of RAFM steel JLF-1 using tensile and low cycle fatigue experiments

Energy Technology Data Exchange (ETDEWEB)

Msolli, S., E-mail: sabeur.msolli@univ-lorraine.fr

2014-08-01

In this paper, a modeling of the elastoviscoplastic behavior of a Reduced Activation Ferritic Martensitic (RAFM) steel JLF-1 is presented. The modeling of this material was based on various Low Cycle Fatigue (LCF) and tensile tests performed in air and vacuum using different imposed strain rates and temperature ranges going from ambient temperature to 873 K. The coupled viscoplastic model is coded in FORTRAN program, implemented into the finite elements code ABAQUS and used to predict the thermomechanical behavior of a fatigue specimen made of RAFM steel JLF-1. Good agreements were found between numerical results and experimental data.

Antagonistic effect of Lactobacillus strains against gas-producing coliforms isolated from colicky infants

Directory of Open Access Journals (Sweden)

Oggero Roberto

2011-06-01

Full Text Available Abstract Background Infantile colic is a common disturb within the first 3 months of life, nevertheless the pathogenesis is incompletely understood and treatment remains an open issue. Intestinal gas production is thought to be one of the causes of abdominal discomfort in infants suffering from colic. However, data about the role of the amount of gas produced by infants' colonic microbiota and the correlation with the onset of colic symptoms are scanty. The benefit of supplementation with lactobacilli been recently reported but the mechanisms by which they exert their effects have not yet been fully defined. This study was performed to evaluate the interaction between Lactobacillus spp. strains and gas-forming coliforms isolated from stools of colicky infants. Results Strains of coliforms were isolated from stools of 45 colicky and 42 control breastfed infants in McConkey Agar and identified using PCR with species-specific primers, and the BBL™ Enterotube™ II system for Enterobacteriaceae. Gas-forming capability of coliforms was assessed in liquid cultures containing lactose as sole carbon source. The average count of total coliforms in colicky infants was significantly higher than controls: 5.98 (2.00-8.76 log10 vs 3.90 (2.50-7.10 CFU/g of faeces (p = 0.015. The following strains were identified: Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, Enterobacter cloacae and Enterococcus faecalis. Then, 27 Lactobacillus strains were tested for their antagonistic effect against coliforms both by halo-forming method and in liquid co-cultures. Lactobacillus delbrueckii subsp.delbrueckii DSM 20074 and L. plantarum MB 456 were able to inhibit all coliforms strains (halo-forming method, also in liquid co-cultures, thus demonstrating an antagonistic activity. Conclusions This study shows that two out of 27 strains of Lactobacillus examined possess an antimicrobial effect against six species of gas-forming coliforms

Antagonistic effect of Lactobacillus strains against gas-producing coliforms isolated from colicky infants.

Science.gov (United States)

Savino, Francesco; Cordisco, Lisa; Tarasco, Valentina; Locatelli, Emanuela; Di Gioia, Diana; Oggero, Roberto; Matteuzzi, Diego

2011-06-30

Infantile colic is a common disturb within the first 3 months of life, nevertheless the pathogenesis is incompletely understood and treatment remains an open issue. Intestinal gas production is thought to be one of the causes of abdominal discomfort in infants suffering from colic. However, data about the role of the amount of gas produced by infants' colonic microbiota and the correlation with the onset of colic symptoms are scanty. The benefit of supplementation with lactobacilli been recently reported but the mechanisms by which they exert their effects have not yet been fully defined. This study was performed to evaluate the interaction between Lactobacillus spp. strains and gas-forming coliforms isolated from stools of colicky infants. Strains of coliforms were isolated from stools of 45 colicky and 42 control breastfed infants in McConkey Agar and identified using PCR with species-specific primers, and the BBL™ Enterotube™ II system for Enterobacteriaceae. Gas-forming capability of coliforms was assessed in liquid cultures containing lactose as sole carbon source. The average count of total coliforms in colicky infants was significantly higher than controls: 5.98 (2.00-8.76) log10 vs 3.90 (2.50-7.10) CFU/g of faeces (p = 0.015). The following strains were identified: Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, Enterobacter cloacae and Enterococcus faecalis. Then, 27 Lactobacillus strains were tested for their antagonistic effect against coliforms both by halo-forming method and in liquid co-cultures. Lactobacillus delbrueckii subsp. delbrueckii DSM 20074 and L. plantarum MB 456 were able to inhibit all coliforms strains (halo-forming method), also in liquid co-cultures, thus demonstrating an antagonistic activity. This study shows that two out of 27 strains of Lactobacillus examined possess an antimicrobial effect against six species of gas-forming coliforms isolated from colicky infants. Our findings may stimulate

Formation Energies of Native Point Defects in Strained-Layer Superlattices (Postprint)

Science.gov (United States)

2017-06-05

potential; bulk materials; total energy calculations; entropy; strained- layer superlattice (SLS) 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...AFRL-RX-WP-JA-2017-0217 FORMATION ENERGIES OF NATIVE POINT DEFECTS IN STRAINED- LAYER SUPERLATTICES (POSTPRINT) Zhi-Gang Yu...2016 Interim 11 September 2013 – 5 November 2016 4. TITLE AND SUBTITLE FORMATION ENERGIES OF NATIVE POINT DEFECTS IN STRAINED- LAYER SUPERLATTICES

Construction of new synthetic biology tools for the control of gene expression in the cyanobacterium Synechococcus sp. strain PCC 7002.

Science.gov (United States)

Zess, Erin K; Begemann, Matthew B; Pfleger, Brian F

2016-02-01

Predictive control of gene expression is an essential tool for developing synthetic biological systems. The current toolbox for controlling gene expression in cyanobacteria is a barrier to more in-depth genetic analysis and manipulation. Towards relieving this bottleneck, this work describes the use of synthetic biology to construct an anhydrotetracycline-based induction system and adapt a trans-acting small RNA (sRNA) system for use in the cyanobacterium Synechococcus sp. strain PCC 7002. An anhydrotetracycline-inducible promoter was developed to maximize intrinsic strength and dynamic range. The resulting construct, PEZtet , exhibited tight repression and a maximum 32-fold induction upon addition of anhydrotetracycline. Additionally, a sRNA system based on the Escherichia coli IS10 RNA-IN/OUT regulator was adapted for use in Synechococcus sp. strain PCC 7002. This system exhibited 70% attenuation of target gene expression, providing a demonstration of the use of sRNAs for differential gene expression in cyanobacteria. These systems were combined to produce an inducible sRNA system, which demonstrated 59% attenuation of target gene expression. Lastly, the role of Hfq, a critical component of sRNA systems in E. coli, was investigated. Genetic studies showed that the Hfq homolog in Synechococcus sp. strain PCC 7002 did not impact repression by the engineered sRNA system. In summary, this work describes new synthetic biology tools that can be applied to physiological studies, metabolic engineering, or sRNA platforms in Synechococcus sp. strain PCC 7002. © 2015 Wiley Periodicals, Inc.

Total aircraft flight-control system - Balanced open- and closed-loop control with dynamic trim maps

Science.gov (United States)

Smith, G. A.; Meyer, G.

1979-01-01

The availability of the airborne digital computer has made possible a Total Aircraft Flight Control System (TAFCOS) that uses virtually the complete nonlinear propulsive and aerodynamic data for the aircraft to construct dynamic trim maps that represent an inversion of the aircraft model. The trim maps, in series with the aircraft, provide essentially a linear feed-forward path. Basically, open-loop trajectory control is employed with only a small perturbation feedback signal required to compensate for inaccuracy in the aircraft model and for external disturbances. Simulation results for application to an automatic carrier-landing system are presented. Flight-test results for a STOL aircraft operating automatically over a major portion of its flight regime are presented. The concept promises a more rapid and straightforward design from aerodynamic principles, particularly for highly nonlinear configurations, and requires substantially less digital computer capacity than conventional automatic flight-control system designs.

Patient-Controlled Oral Analgesia for Postoperative Pain Management Following Total Knee Replacement

Directory of Open Access Journals (Sweden)

Patti Kastanias

2010-01-01

Full Text Available PURPOSE: To investigate whether patient-controlled oral analgesia (PCOA used by individuals receiving a total knee replacement could reduce pain, increase patient satisfaction, reduce opioid use and/or reduce opioid side effects when compared with traditional nurse (RN-administered oral analgesia.

Functional exercise after total hip replacement (FEATHER a randomised control trial

Directory of Open Access Journals (Sweden)

Monaghan Brenda

2012-11-01

Full Text Available Abstract Background Prolonged physical impairments in range of movement, postural stability and walking speed are commonly reported following total hip replacement (THR. It is unclear from the current body of evidence what kind of exercises should be performed to maximize patient function and quality of life. Methods/design This will be a single blind multi centre randomized control trial with two arms. Seventy subjects post primary total hip arthroplasty will be randomized into either an experimental group (n=35, or to a control group (n=35. The experimental group will attend a functional exercise class twice weekly for a six week period from week 12 to week 18 post surgery. The functional exercise group will follow a circuit based functional exercise class supervised by a chartered Physiotherapist. The control group will receive usual care. The principal investigator (BM will perform blinded outcome assessments on all patients using validated measures for pain, stiffness, and function using the Western Ontario and Mc Master Universities Osteoarthritis index (WOMAC. This is the primary outcome measurement tool. Secondary outcome measurements include Quality of life (SF-36, 6 min walk test, Visual Analogue Scale, and the Berg Balance score. The WOMAC score will be collated on day five post surgery and repeated at week twelve and week eighteen. All other measurements will be taken at week 12 and repeated at week eighteen. In addition a blinded radiologist will measure gluteus medius cross sectional area using real time ultrasound for all subjects at week 12 and at week 18 to determine if the functional exercise programme has any effect on muscle size. Discussion This randomised controlled trial will add to the body of evidence on the relationship between muscle size, functional ability, balance, quality of life and time post surgery in patients following total hip arthroplasty. The CONSORT guidelines will be followed to throughout. Ethical

Seismic qualification of piping systems based on strain criteria

International Nuclear Information System (INIS)

Peters, K.; Rangette, A.

1988-01-01

Typical LMFBR piping is characterized by elevated temperature and low pressure levels. Taking into account operational conditions only these characteristics demand for and allow flexible piping design. The overestimation of the damage potential of seismic loading by e.g. improper failure criteria usually contradicts operational needs producing the known result of excessive ''snubberism'' and reduction of operational margins. As a matter of fact, due to its transiency seismic loading is essentially secondary provoking the natural design requirement ductility instead of stiffness and rigidity - i.e. exclusion of failure by strain control instead of stress control - and thus avoiding the LMFBR typical competition between operational needs and seismic qualification. The design requirement ductility needs judgement mechanisms, i.e. suitable load descriptions, allowed strain levels and strain evaluation tools. A simplified method for strain range estimation and the underlying basic ideas are roughly outlined. The status of verification and experience gained so far is described. The results achieved suggest that the qualification of piping based on ductility requirement controlled by strain criteria is not out of reach. (author)

Pre-fermentative cold maceration in presence of non-Saccharomyces strains: Evolution of chromatic characteristics of Sangiovese red wine elaborated by sequential inoculation.

Science.gov (United States)

Benucci, Ilaria; Cerreti, Martina; Liburdi, Katia; Nardi, Tiziana; Vagnoli, Paola; Ortiz-Julien, Anne; Esti, Marco

2018-05-01

Two different Metschnikowia strains (M. pulcherrima MP 346 or M. fructicola MF 98-3) were applied for the first time, during pre-fermentative cold maceration (PCM) in order to enhance the properties and stability of Sangiovese wine color. During the 2014 and 2015 vintages a total of eight wines were produced with 24 h of cold maceration (PCM 24 h) or 72 h (PCM 72 h), respectively. PCM was carried out in presence of MP 346 or MF 98-3 or pectic enzyme (Cuvée Rouge). The sequential inoculation of S. cerevisiae strain was carried out at the end of PCM. After 12 months in the bottle, the MP 346 and MF 98-3 wines contained much higher levels of total flavonoids than the Control sample for both vintages and regardless PCM duration. Moreover, in both vintages only MF 98-3 showed a higher color intensity than the Control sample after 12 months in the bottle. However, neither PCM duration nor the microbial/enzymatic treatment increased the level of anthocyanins at draining off. Both wines produced by the pre-fermentative inoculum with Metschnikowia strains (MP 346 and MF 98-3) retained their red hue, regardless the duration of pre-fermentative and fermentative macerations, while the Control wines were characterized by faster rates of color loss. Copyright © 2018 Elsevier Ltd. All rights reserved.

Controlling total spot power from holographic laser by superimposing a binary phase grating.

Science.gov (United States)

Liu, Xiang; Zhang, Jian; Gan, Yu; Wu, Liying

2011-04-25

By superimposing a tunable binary phase grating with a conventional computer-generated hologram, the total power of multiple holographic 3D spots can be easily controlled by changing the phase depth of grating with high accuracy to a random power value for real-time optical manipulation without extra power loss. Simulation and experiment results indicate that a resolution of 0.002 can be achieved at a lower time cost for normalized total spot power.

Mumps vaccine virus strains and aseptic meningitis.

Science.gov (United States)

Bonnet, Marie-Claude; Dutta, Anil; Weinberger, Clement; Plotkin, Stanley A

2006-11-30

Mumps immunization can easily be included in national schedules, particularly if combined with measles or measles and rubella vaccines, but debate continues concerning the relative safety of various licensed mumps vaccine strains. The opportunities for control of mumps are also being affected by differences in the cost of the vaccines prepared with different strains of mumps virus. The present report evaluates available data on the association of the Urabe and other strains of mumps vaccine with the occurrence of aseptic meningitis. We also review the comparative immunogenicity and efficacies of the most widely used mumps vaccines in controlled clinical trials and field evaluations, and briefly examine relative cost as it relates to the implementation of national immunization programs. We conclude that extensive experience with the most widely used mumps vaccine strains in many countries has shown that the risk-benefit ratio of live mumps vaccines is highly favourable for vaccination, despite the occasional occurence of aseptic meningitis.

Japanese style total quality control: A first hand experience

Science.gov (United States)

Cook, S. C.

1991-11-01

The scope, concepts and practices of Total Quality Control (TQC) as operated in Japan today are described. The following mechanisms and elements are introduced: policy deployment, cross functional management, small group activities, suggestion systems, standardization, the TQC promotion department, and TQC education. It is shown on a practical level, how TQC operates in the research and engineering divisions of the aeroengine and space operation at Ishikawajima Harima Industries in Japan. Japanese style TQC is a well developed, well promoted, well structured, common approach to achieving customer satisfaction through continuous improvements. Furthermore, TQC itself is being continuously improved with the Japanese still refining, extending, and developing TQC.

Synthesis of siderophores by strains of Staphylococcus cohnii isolated from various environments.

Science.gov (United States)

Szarapińska-Kwaszewska, Jadwiga; Farkas, Lukasz I

2003-01-01

Siderophore activity as the feature of microorganisms enabling colonization of human body and the survival in inanimate environment was investigated in 108 strains of Staphylococcus cohnii; S. cohnii ssp. cohnii (50 strains) and S. cohnii ssp. urealyticus (58 strains). Strains were isolated from people, hospital and non-hospital environment. Highest siderophore activity was noted in strains S. cohnii ssp. urealyticus particularly from the inanimate environments origin. In 86% analyzed strains siderophores of hydroxamate class were detected. Larger amounts of these compounds were synthesized in strains S. cohnii ssp. urealyticus. Strains belonging to both subspecies from human origin showed lower activity of siderophores (total pool) and did not produce hydroxamate class chelators or produced very small amounts of these compounds.

Draft genome sequence of Bradyrhizobium sp. strain BR 3267, an elite strain recommended for cowpea inoculation in Brazil

Directory of Open Access Journals (Sweden)

Jean Luiz Simões-Araújo

Full Text Available Abstract The strain BR 3267 is a nitrogen-fixing symbiotic bacteria isolated from soil of semi-arid area of Brazilian Northeast using cowpea as the trap plant. This strain is used as commercial inoculant for cowpea and presents high efficient in nitrogen fixation as consequence of its adaptation potential to semi-arid conditions. We report here the draft genome sequence of Bradyrhizobium sp. strain BR 3267, an elite bacterium used as inoculant for cowpea. Whole genome sequencing of BR 3267 using Illumina MiSeq sequencing technology has 55 scaffolds with a total genome size of 7,904,309 bp and C+G 63%. Annotation was added by the RAST prokaryotic genome annotation service and has shown 7314 coding sequences and 52 RNA genes.

Transformation of Silver Nanoparticles in Sewage Sludge during Incineration.

Science.gov (United States)

Meier, Christoph; Voegelin, Andreas; Pradas del Real, Ana; Sarret, Geraldine; Mueller, Christoph R; Kaegi, Ralf

2016-04-05

Silver nanoparticles (Ag-NP) discharged into the municipal sewer system largely accumulate in the sewage sludge. Incineration and agricultural use are currently the most important strategies for sewage sludge management. Thus, the behavior of Ag-NP during sewage sludge incineration is essential for a comprehensive life cycle analysis and a more complete understanding of the fate of Ag-NP in the (urban) environment. To address the transformation of Ag-NP during sewage sludge incineration, we spiked metallic Ag(0)-NP to a pilot wastewater treatment plant and digested the sludge anaerobically. The sludge was then incinerated on a bench-scale fluidized bed reactor in a series of experiments under variable conditions. Complementary results from X-ray absorption spectroscopy (XAS) and electron microscopy-energy dispersive X-ray (EM-EDX) analysis revealed that Ag(0)-NP transformed into Ag2S-NP during the wastewater treatment, in agreement with previous studies. On the basis of a principal component analysis and subsequent target testing of the XAS spectra, Ag(0) was identified as a major Ag component in the ashes, and Ag2S was clearly absent. The reformation of Ag(0)-NP was confirmed by EM-EDX. The fraction of Ag(0) of the total Ag in the ashes was quantified by linear combination fitting (LCF) of XAS spectra, and values as high as 0.8 were found for sewage sludge incinerated at 800 °C in a synthetic flue gas atmosphere. Low LCF totals (72% to 94%) indicated that at least one relevant reference spectrum was missing in the LCF analysis. The presence of spherical Ag-NP with a diameter of incineration, as demonstrated in this study, needs to be considered in the life cycle assessment of engineered Ag-NP.

Molecular Detection of Aflatoxin Producing Strains of Aspergillus Flavus from Peanut (Arachis Hypogaea

Directory of Open Access Journals (Sweden)

Adeela Hussain

2015-02-01

Full Text Available Aflatoxins are the potential carcinogens produced as secondary metabolites by Aspergillus flavus. They have the ability to contaminate large number of food which ultimately affect the human population. Malt extract agar was selected for the growth of control stains of fungus. The aim of the study was to develop a reliable and quick method for the detection of aflatoxin producing strains in peanuts by using molecular approaches. Total 80 samples of infected peanuts were collected from four different cities of Punjab and checked for their aflatoxin contamination. For aflatoxin detection, three target genes nor1, ver1 and aflR were selected which was involved in the aflatoxin biosynthesis. In all examined cases, 24 out of 80 (30% samples successfully amplified all three genes indicating aflatoxigenic activity. Discrimination between aflatoxigenic and non-aflatoxigenic strains were also determined on the basis of amplification of these three target DNA fragments. In this study, it was also demonstrated that only specific strains were able to produce the aflatoxin contamination in peanuts.

Role of some selected Bifidobacterium strains in modulating immunosenescence of aged albino rats

Directory of Open Access Journals (Sweden)

Hanan A. El-Bakry

2013-10-01

Full Text Available Probiotic administration has been associated with enhanced immune function in elderly subjects. However, approaches for selection of an “ideal” strain of bifidobacteria are still difficult. The aim of the present study is to investigate the possible modulatory effects of three strains of Bifidobacterium species (Bifidobacterium adolescentis ATCC 15704, Bifidobacterium breve ATCC 15700 and Bifidobacterium longum ATCC 15707 on haematological and immunological parameters of aged albino rats corresponding to normal adult ones. The animals were divided into six groups; three groups of aged rats were fed yoghurt inoculated with one of the Bifidobacterium strains; one group of aged rats was fed yoghurt alone (control aged; two groups of adult and aged rats were provided with normal diet and assigned as normal groups. The total leucocyte count was significantly increased in the three bifidobacteria-treated aged groups as compared with both normal and control aged rats. Serum IgA level was considerably increased in all treated rats. On the contrary, serum IgE level was significantly decreased in rats supplemented with yoghurt inoculated with B. adolescentis or B. breve. Both B. adolescentis and B. breve groups showed significant enhanced production of TNF-α. Furthermore, the production of cytokine IL-8 was significantly increased in the B. adolescentis group. Interestingly, it was apparent that only B. adolescentis had the most pronounced effect on aged rats to regain nearly normal values as measured in normal adult rats. Conclusively, the present work indicates that dietary consumption of selected bifidobacteria strains may have a particular application in the elderly especially in terms of immunomodulation.

Strain-enhanced tunneling magnetoresistance in MgO magnetic tunnel junctions

OpenAIRE

Loong, Li Ming; Qiu, Xuepeng; Neo, Zhi Peng; Deorani, Praveen; Wu, Yang; Bhatia, Charanjit S.; Saeys, Mark; Yang, Hyunsoo

2014-01-01

While the effects of lattice mismatch-induced strain, mechanical strain, as well as the intrinsic strain of thin films are sometimes detrimental, resulting in mechanical deformation and failure, strain can also be usefully harnessed for applications such as data storage, transistors, solar cells, and strain gauges, among other things. Here, we demonstrate that quantum transport across magnetic tunnel junctions (MTJs) can be significantly affected by the introduction of controllable mechanical...

Modeling of the influence of coarsening on viscoplastic behavior of a 319 foundry aluminum alloy

International Nuclear Information System (INIS)

Martinez, R.; Russier, V.; Couzinié, J.P.; Guillot, I.; Cailletaud, G.

2013-01-01

Both metallurgical and mechanical behaviors of a 319 foundry aluminum alloy have been modeled by means of a multiscale approach. The nano-scale, represented by the coarsening of Al 2 Cu precipitates, has been modeled according to the Lifshitz–Slyozov–Wagner (LSW) law in a range of temperature going from 23 °C to 300 °C up to 1000 h aging time. Results were then compared to transmission electron microscope (TEM) observations and are in good agreement with the experimental measurements. The model allows us to know the critical radius, the volume fraction and the number of particles per μm 3 in a α-phase representative volume element (RVE). The increase in yield stress generated by the interaction of dislocations with precipitates, lattice and solid solution, is modeled on the microscale. The yield stress becomes thus a function of the precipitation state, and is time/temperature dependent. These two models were then combined into a mechanical macroscale model in order to represent the Low Cycle Fatigue (LCF) behavior of the material. An elasto-viscoplastic law has been used and all the material parameters were experimentally determined with LCF stress/strain loops for the first cycle and for the mechanical steady state. The simulation results are in good agreement with the experiments.

Human fibroblast strain with normal survival but abnormal postreplication repair after ultraviolet light irradiation

International Nuclear Information System (INIS)

Doniger, J.; Barrett, S.F.; Robbins, J.H.

1980-01-01

Postreplication repair has been studied in ultraviolet light (UV-irradiated) fibroblast strains derived from eight apparently normal control donors and seven xeroderma pigmentosum patients. One control donor strain had an intermediate defect in postreplication repair similar to that in excision-deficient xeroderma pigmentosum fibroblasts. However, unlike the xeroderma pigmentosum strains, this control donor strain had normal UV-induced unscheduled DNA synthesis and normal survival after irradiation with UV. This unique fibroblast strain should be useful in studies designed to elucidate the possible role of postreplication repair in UV-induced carcinogenesis and mutagenesis

ECG strain pattern in hypertension is associated with myocardial cellular expansion and diffuse interstitial fibrosis: a multi-parametric cardiac magnetic resonance study.

Science.gov (United States)

Rodrigues, Jonathan C L; Amadu, Antonio Matteo; Ghosh Dastidar, Amardeep; McIntyre, Bethannie; Szantho, Gergley V; Lyen, Stephen; Godsave, Cattleya; Ratcliffe, Laura E K; Burchell, Amy E; Hart, Emma C; Hamilton, Mark C K; Nightingale, Angus K; Paton, Julian F R; Manghat, Nathan E; Bucciarelli-Ducci, Chiara

2017-04-01

In hypertension, the presence of left ventricular (LV) strain pattern on 12-lead electrocardiogram (ECG) carries adverse cardiovascular prognosis. The underlying mechanisms are poorly understood. We investigated whether hypertensive ECG strain is associated with myocardial interstitial fibrosis and impaired myocardial strain, assessed by multi-parametric cardiac magnetic resonance (CMR). A total of 100 hypertensive patients [50 ± 14 years, male: 58%, office systolic blood pressure (SBP): 170 ± 30 mmHg, office diastolic blood pressure (DBP): 97 ± 14 mmHg) underwent ECG and 1.5T CMR and were compared with 25 normotensive controls (46 ± 14 years, 60% male, SBP: 124 ± 8 mmHg, DBP: 76 ± 7 mmHg). Native T1 and extracellular volume fraction (ECV) were calculated with the modified look-locker inversion-recovery sequence. Myocardial strain values were estimated with voxel-tracking software. ECG strain (n = 20) was associated with significantly higher indexed LV mass (LVM) (119 ± 32 vs. 80 ± 17 g/m2, P ECG strain (n = 80). ECG strain subjects had significantly impaired circumferential strain compared with hypertensive subjects without ECG strain and controls (-15.2 ± 4.7 vs. -17.0 ± 3.3 vs. -17.3 ± 2.4%, P ECG strain subjects to hypertensive subjects with elevated LVM but no ECG strain, a significantly higher ECV (30 ± 4 vs. 28 ± 3%, P ECG strain in multivariate logistic regression analysis [odds ratio (95th confidence interval): 1.07 (1.02-1.12), P ECG strain is a marker of advanced LVH associated with increased interstitial fibrosis and associated with significant myocardial circumferential strain impairment. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Cardiology.

A host-specific biological control of grape crown gall by Agrobacterium vitis strain F2/5: its regulation and population dynamics.

Science.gov (United States)

Kaewnum, Supaporn; Zheng, Desen; Reid, Cheryl L; Johnson, Kameka L; Gee, Jodi C; Burr, Thomas J

2013-05-01

Nontumorigenic Agrobacterium vitis strain F2/5 is able to prevent crown gall caused by tumorigenic A. vitis on grape but not on other plant species such as tobacco. Mutations in a quorum-sensing transcription factor, aviR, and in caseinolytic protease (clp) component genes clpA and clpP1 resulted in reduced or loss of biological control. All mutants were complemented; however, restoration of biological control by complemented clpA and clpP1 mutants was dependent on the copy number of vector that was used as well as timing of application of the complemented mutants to grape wounds in relation to inoculation with pathogen. Mutations in other quorum-sensing and clp genes and in a gene associated with polyketide synthesis did not affect biological control. It was determined that, although F2/5 inhibits transformation by tumorigenic A. vitis strains on grape, it does not affect growth of the pathogen in wounded grape tissue over time.

[Case-control study on effect of rivaroxaban on the risk of hidden bleeding after total hip arthroplasty].

Science.gov (United States)

Li, Jun; Jing, Jue-Hua; Shi, Zhan-Jun; Zhou, Yun

2014-01-01

To investigate the risk of hidden blood loss about applying rivaroxaban after total hip arthroplasty. From October 2009 to May 2012,88 patients with femoral head necrosis were treated with primary total hip arthroplasty. All the patients were divided into Rivaroxaban group(44 cases)and control group(44 cases). There were 25 males and 19 females in the Rivaroxaban group, with an average age of (58.48 +/- 15.19) years old; in the control group,24 patients were male and 20 patients were female, with an average age of (61.11 +/- 13.54) years old. The patients in the Rivaroxaban group took Rivaroxaban orally from the first day after operation with a dose of 10 mg each day, and treatment course was 14 days. The patients in the control group took placebo orally at the same time. Dominant blood loss and transfusion were recorded, blood routine examinations were taken before operation and at 3 days after operation. The total blood loss and hidden blood loss were calculated according to the formula. The mean total blood loss was (1509.56 +/- 325.23) ml and the hidden blood loss was(581.47 +/- 215.01) ml, accounting for (37.88 +/- 10.42)% in the Rivaroxaban group. The mean total blood loss was (1262.30 +/- 397.95) ml and the hidden blood loss was (395.59 +/- 97.33) ml, accounting for (30.62 +/- 0.20)% in the control group. The total blood loss, hidden blood loss and transfusion in the Rivaroxaban group was significantly more than those in control group,b ut there was no significant difference on dominant blood loss between two groups. Rivaroxaban increased the overall bleeding risk of total hip arthroplasty, especially hidden bleeding risk, which should be careful used.

77 FR 55166 - Airworthiness Directives; Sikorsky Aircraft Corporation (Sikorsky) Model Helicopters

Science.gov (United States)

2012-09-07

... card or equivalent record that count at the end of each day for which the HR is inoperative. Costs of... cycle events and record on the component card or equivalent record that count at the end of each day for... formulas and LCF Limit Diagrams, and specify counting LCF events to determine the remaining fatigue life...

Potential of a strain of the entomopathogenic fungus Beauveria bassiana (Hypocreales: Cordycipitaceae) as a biological control agent against western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae)

Science.gov (United States)

Five Beauveria bassiana strains were evaluated for control of western flower thrips. Strain RSB was the most virulent, causing 69-96% mortality at concentrations of 1×104 – 1×107 conidia mL-1, 10 days after inoculation of first instars. In greenhouse trials, RSB applied to broccoli foliage signifi...

Whole body and tissue blood volumes of two strains of rainbow trout (Oncorhynchus mykiss)

Science.gov (United States)

Gingerich, W.H.; Pityer, R.A.; Rach, J.J.

1990-01-01

1. Estimates of apparent packed cell, plasma and total blood volumes for the whole body and for 13 selected tissues were compared between Kamloops and Wytheville strains of rainbow trout (Oncorhynchus mykiss) by the simultaneous injection of two vascular tracers, radiolabeled trout erythrocytes (51Cr-RBC) and radioiodated bovine serum albumin (125I-BSA).2. Whole body total blood volume, plasma volume and packed cell volume were slightly, but not significantly greater in the Wytheville trout, whereas, the apparent plasma volumes and total blood volumes in 4 of 13 tissues were significantly greater in the Kamloops strain.3. Differences were most pronounced in highly perfused organs, such as the liver and kidney and in organs of digestion such as the stomach and intestines.4. Differences in blood volumes between the two strains may be related to the greater permeability of the vascular membranes in the Kamloops strain fish.

Characteristics of clinical Helicobacter pylori strains from Ecuador.

Science.gov (United States)

Debets-Ossenkopp, Yvette J; Reyes, Germán; Mulder, Janet; aan de Stegge, Birgit M; Peters, José T A M; Savelkoul, Paul H M; Tanca, J; Peña, Amado S; Vandenbroucke-Grauls, Christina M J E

2003-01-01

In Ecuador, Helicobacter pylori infections are highly prevalent. A total of 42 H. pylori clinical isolates from 86 patients attending the outpatient clinic of the gastroenterology department of the university hospital of Guayaquil in Ecuador were characterized. Their susceptibility, and cagA and vacA status were determined. Resistance to metronidazole and clarithromycin was found in 80.9% and 9.5% of strains, respectively. Neither amoxicillin- nor tetracycline-resistant strains were found. The most prevalent genotype was the cagA(+), vacA s1b,m1 type. This genotype was associated with gastric cancer and peptic ulcer. Typing by random amplified polymorphic DNA showed no genetic relationship among the strains.

Strain-based failure criteria for steel containments

International Nuclear Information System (INIS)

Fanous, F.; Greimann, L.F.

1989-01-01

The Containment Integrity Division of the Sandia National Laboratories (Sandia) has been conducting a program to evaluate the performance of containment buildings with internal pressure. Sandia has suggested that in the absence of leakage past penetrations, containment buildings will fail by rupturing after large plastic strains are developed up to ultimate strain of the material. This paper represents a portion of work conducted at Ames Laboratory for Sandia, the objective of which was to identify fabrication details that may affect the performance of a containment building. Construction drawings for nine steel containment buildings were surveyed, and several significant strain concentration regions were identified by using recommendations from Sandia and Section NE-3217 of the ASME Boiler and Pressure Vessel Code. These following regions were identified as: eccentricities in stiffener patterns around penetrations, eccentricities in containment shell middle surface, flat plate covers used on spare penetrations, containment base connection details, and containment heads. Examples of each of these regions were analyzed by the finite-element method, by simplified equations or both. In the case of middle surface eccentricities, the strains were found to be self-limiting. Even though flat plates have primary strains, they are typically designed so as not to control. Bolts in the base connection have primary strains and may control. The circumferential compressive strains introduced at the knuckle during buckling of the containment head grow as the pressure increases, but are somewhat restricted by the meridional tension. Finally, three analysis techniques and their associated failure criteria for the analysis of containment strength are introduced. (orig.)

The Marine Fungi Rhodotorula sp. (Strain CNYC4007) as a Potential Feed Source for Fish Larvae Nutrition

Science.gov (United States)

Barra, M.; Llanos-Rivera, A.; Cruzat, F.; Pino-Maureira, N.; González-Saldía, R. R.

2017-01-01

Fish oil is used in the production of feed for cultured fish owing to its high polyunsaturated fatty acid content (PUFA). The over-exploitation of fisheries and events like “El Niño” are reducing the fish oil supply. Some marine microorganisms are considered potentially as alternative fatty acid sources. This study assesses a strain of Rhodotorula sp. (strain CNYC4007; 27% docosahexaenoic acid (DHA) of total fatty acids), as feed for fish larvae. The total length and ribonucleic acid (RNA)/deoxyribonucleic acid (DNA) ratio of Danio rerio larvae was determined at first feeding at six and 12 days old (post-yolk absorption larvae). Larvae fed with microencapsulated Rhodotorula sp. CNYC4007 had a significantly higher RNA/DNA ratio than control group (C1). At six days post-yolk absorption group, the RNA/DNA ratio of larvae fed with Rhodotorula sp. bioencapsulated in Brachionus sp. was significantly higher than control group fed with a commercial diet high in DHA (C2-DHA). Finally, at 12 days post-yolk absorption, the RNA/DNA ratio was significantly higher in larvae fed with Rhodotorula sp. CNYC4007 and C2-DHA (both bioencapsulated in Artemia sp. nauplii) than in control group (C1). These results suggest that Rhodotorula sp. CNYC4007 can be an alternative source of DHA for feeding fish at larval stage, providing a sustainable source of fatty acids. PMID:29194350

Faulting of rocks in three-dimensional strain fields I. Failure of rocks in polyaxial, servo-control experiments

Science.gov (United States)

Reches, Ze'ev; Dieterich, James H.

1983-05-01

The dependence of the number of sets of faults and their orientation on the intermediate strain axis is investigated through polyaxial tests, reported here, and theoretical analysis, reported in an accompanying paper. In the experiments, cubic samples of Berea sandstone, Sierra-White and Westerly granites, and Candoro and Solnhofen limestones were loaded on their three pairs of faces by three independent, mutually perpendicular presses at room temperature. Two of the presses were servo-controlled and applied constant displacement rates throughout the experiment. Most samples display three or four sets of faults in orthorhombic symmetry. These faults form in several yielding events that follow a stage of elastic deformation. In many experiments, the maximum and the intermediate compressive stresses interchange orientations during the yielding events, where the corresponding strains are constant. The final stage of most experiments is characterized by slip along the faults.

Predicted strains in austenitic stainless steels at stresses above yield

International Nuclear Information System (INIS)

Hammond, J.P.; Sikka, V.K.

1977-01-01

Tensile results on austenitic stainless steels were analyzed to develop means for predicting strains at stresses above yield for reactor regulatory applications. Eight heats each of types 316 and 304 were tested at 24, 93, 204, and 316 0 C as mill-annealed and at 24 0 C after reannealing. The effects of heat-to-heat variations on total strain (to 5%) at discrete stress levels were portrayed by a rational polynomial incorporating three constants that relate to the basic features of the true-stress-true-strain diagram. Because these constants usually are interrelated, a single parameter, yield strength (YS), proved adequate to predict results. For predictions analytical expressions of yield strength, an average value (YSa), and a lower bound value [YSa - 1.65SEE (standard error of estimate)] were used. Using the rational polynomial with these parameters we determined (1) limits of total maximum strain and (2) ratios of strain of material of lower bound YS to that of average YS. These are recorded at regular increments of stress [34 MPa (5 ksi)] and at ASME Code-related stresses (S/sub y), S/sub m/, 1.2S/sub m/ and 1.5S/sub m/). At intermediate stresses, strain penalties for using material of lower bound strength were large, generally larger for type 316 than type 304. For mill-annealed type 316 at 24, 93, 204, and 316 0 C, the maximum ratios of strain were 8.8, 13.0, 14.1, and 14.9, respectively, whereas for type 304 they were 3.5, 3.4, 5.6, and 4.6. At 1.5S/sub m/ and 316 0 C, a maximum strain of 2.08% was predicted for type 316 and 1.66% for type 304, as contrasted to values of 0.14 and 0.39% for average strain

Effects of strain on the Schwinger pair creation in graphene

International Nuclear Information System (INIS)

Fanbanrai, P.; Hutem, A.; Boonchui, S.

2015-01-01

The effects of strain on mechanically deformed graphene are determined by looking at how the strain affects the amplitude of the Schwinger two particle pair state. The influences of the lattice distortions, such as isotropic tensile strain ϵ is , shear strain ϵ ss , uniaxial armchair strain ϵ as , and zigzag strain ϵ zs , on the photon emission spectrum have been analyzed. We find that the intensities of the emission increases or decreases when compared to those of the unstrained graphene, depending on the type of strain applied. Thus the structure of energy band, the frequencies of the photons and the emission spectrum can be controlled by use of the different strains

Foot loading with an ankle-foot orthosis: the accuracy of an integrated physical strain trainer.

Science.gov (United States)

Pauser, Johannes; Jendrissek, Andreas; Brem, Matthias; Gelse, Kolja; Swoboda, Bernd; Carl, Hans-Dieter

2012-07-01

To investigate the value of a built-in physical strain trainer for the monitoring of partial weight bearing with an ankle-foot orthosis. 12 healthy volunteers were asked to perform three trials. Plantar peak pressure values from normal gait (trial one) were defined as 100% (baseline). The following trials were performed with the Vacoped® dynamic vacuum ankle orthosis worn in a neutral position with full weight bearing (trial two) and a restriction to 10% body weight (BW) (trial three), as monitored with an integrated physical strain trainer. Peak plantar pressure values were obtained using the pedar® X system. Peak pressure values were statistically significantly reduced wearing the Vacoped® shoe with full weight bearing for the hindfoot to 68% of the baseline (normal gait) and for the midfoot and forefoot to 83% and 60%, respectively. Limited weight bearing with 10% BW as controlled by physical strain trainer further reduced plantar peak pressure values for the hindfoot to 19%, for the midfoot to 43% of the baseline and the forefoot to 22% of the baseline. The Vacoped® vacuum ankle orthosis significantly reduces plantar peak pressure. The integrated physical strain trainer seems unsuitable to monitor a limitation to 10% BW adequately for the total foot. The concept of controlling partial weight bearing with the hindfoot-addressing device within the orthosis seems debatable but may be useful when the hindfoot in particular must be off-loaded.

Use of gamma radiation for increasing plant disease control efficacy

International Nuclear Information System (INIS)

Chamswarng, Chiradej; Intanoo, Wanwilai; Piadang, Nattayana

2006-09-01

Irradiation of Trichoderma harzianum with 0.5-8.0 k Gay of gamma ray revealed 41 strains resistant to 10 ppm propiconazole or benomyl fungicides and two strains (23/03-7 and 27/08-1) were resistant to 10 ppm of both fungicides. After these two mutant strains were repeatedly irradiated with gamma ray, 74 mutant strains were obtained. Among these, three mutant strains, used as seed treatment effectively protected tomato seedlings from the infection of Pythium apanidermatum with significantly higher surviving seedlings than the Pythium inoculated control. The higher root colonization of mutant strains was obtains from strains 03/7-113, 03-/7-114 and 08/1-11. Rice seeds (RD 17), previously soaked in water for 24 ht were placed in spore suspension of T. harzianum prepared from 1 kg of fresh culture of 81 mutant isolated derived from single or double irradiation with gamma ray in 50 1 of water for 30 min. Two mutants including 23/03-7 (derived from single irradiation) and 03/7-134 (derived from double irradiation) provided percentages of root colonization by 29.63 and 25.93, while growth-promoted roots were 12.48 and 12.65 cm in length. respectively. These two strains were tested in rice field by treating pre-soaked seeds with Trichoderma suspensions for 30 min and incubated for 24 hr before sowing. Detection of root colonization by T. harzianum at 35, 45 and 102 days after sowing revealed that all Trichoderma strains effectively colonized rice roots at all stages of growth, particularly two mutants completely colonized rice root at 102 days after sowing. After harvesting, a mutant strain 30/7-134 increased rice yield to the maximum level at 29.65% over a control, while the percentage of fertile-seeds and it's seed weight, total seed weight, fertile-seed weight were significantly higher than a control. However, all Trichoderma strains provided the potential increases of rice yield over a control. Strain 03/7-134 significantly reduced percentage of dirty-panicle diseased

Low cycle fatigue of PM/HIP astroloy

Energy Technology Data Exchange (ETDEWEB)

Choe, S.J.; Stoloff, N.S.; Duquette, D.J. (Rensselaer Polytechnic Institute, Troy, NY (USA))

Low cycle fatigue and creep-fatigue-environment interactions of PM/HIP Astrology were studied at 650 C and 725 C. Total strain range was varied from 1.5% to 2.7% at a frequency of 0.3Hz. Creep-fatigue tests were performed with 2 min. or 5 min. tensile hold times. All tests were run in high purity argon in an attempt to minimize environmental effects. Employing a tensile hold was more damaging than raising temperature by 75 C. Slopes of Coffin-Manson plots were nearly independent of temperature and hold time. Raising temperature from 650 C to 725 C did not change the transgranular (TG) crack propagation mode, whereas employing hold times caused TG+IG propagation. All samples displayed multiple fracture origins associated with inclusions located at the specimen surface; pre-existing pores did not affect fatigue crack initiation. Examination of secondary cracks showed no apparent creep damage. Oxidation in high purity argon appeared to be the major factor in LCF life degradation due to hold times.

[Virulence markers of Escherichia coli O1 strains].

Science.gov (United States)

Makarova, M A; Kaftyreva, L A; Grigor'eva, N S; Kicha, E V; Lipatova, L A

2011-01-01

To detect virulence genes in clinical isolates of Escherichia coli O1 using polymerase chain reaction (PCR). One hundred and twenty strains of E.coli O1 strains isolated from faeces of patients with acute diarrhea (n = 45) and healthy persons (n = 75) were studied. PCR with primers for rfb and fliC genes, which control synthesis of O- and H- antigens respectively, was used. Fourteen virulence genes (pap, aaf, sfa, afa, eaeA, bfpA, ial, hly, cnf, stx1, stx2, lt, st, and aer) were detected by PCR primers. K1-antigen was determined by Pastorex Meningo B/E. coli O1 kit (Bio-Rad). rfb gene controlling O-antigen synthesis in serogroup O1 as well as fliC gene controlling synthesis of H7 and K1 antigens were detected in all strains. Thus all E. coli strains had antigenic structure O1:K1 :H-:F7. Virulence genes aafl, sfa, afa, eaeA, bfpA, ial, hly, cnf, stx1, stx2, lt, and st were not detected. All strains owned pap and aer genes regardless of the presence of acute diarrhea symptoms. It was shown that E. coli O1:KI:H-:F7 strains do not have virulence genes which are characteristic for diarrhea-causing Escherichia. In accordance with the presence of pap and aer genes they could be attributed to uropathogenic Escherichia (UPEC) or avian-pathogenic Escherichia (APEC). It is necessary to detect virulence factors in order to determine E. coli as a cause of intestinal infection.

Effect of gamma radiation on the toxicity of milbemectin and chlorfenapyr in acaricide resistant and susceptible strains of Tetranychus urticae Koch (Acari: Tetranychidae)

Energy Technology Data Exchange (ETDEWEB)

Nicastro, Roberto L.; Arthur, Valter; Machi, Andre R., E-mail: rnicastro@cena.usp.br, E-mail: arthur@cena.usp.br [Laboratorio de Radiobiologia e Ambiente (CENA/USP), Piracicaba, SP (Brazil); Sato, Mario E., E-mail: mesato@biologico.sp.gov.br [Laboratorio de Acarologia, Instituto Biologico, Campinas, SP (Brazil)

2011-07-01

The spider mite Tetranychus urticae Koch is considered one of the most important phytophagous mites, causing considerable damage in several agricultural crops. The aim of this study was to evaluate the effect of gamma radiation on the toxicity of the acaricides milbemectin and chlorfenapyr in resistant and susceptible strains of T. urticae. The R and S strains for milbemectin and chlorfenapyr were irradiated with gamma radiation at Gamma cell-220 source at doses of 5, 10, 20, 40 e 80 Gy. Five concentrations of milbemectin and chlorfenapyr were evaluated, making applications 24 hours after irradiation. Mites of the controls were sprayed with the same acaricide concentrations used for the R and S strains but they were not exposed to gamma radiation. Experiments on the effects of gamma radiation on the growth rates of mites for acaricide resistant and susceptible strains of T. urticae were also carried out. Tests with the Milbemectin S strain showed an increased susceptibility to the acaricide milbemectin, when the mites were irradiated (20 Gy), in comparison with the control (non irradiated mites). For the Milbemectin R strain, there was no significant influence of gamma irradiation on the toxicity of milbemectin to the mites of this strain. For the Chlorfenapyr S strain, the effect of gamma radiation was similar to that observed for Milbemectin S strain, with increased toxicity of chlorfenapyr to the mites of this susceptible strain. In the case of the Chlorfenapyr R strain, the mites exposed to gamma radiation showed to be more tolerant to chlorfenapyr, considering the LC{sub 10} values. The same trend was observed for the LC{sub 50} values, however, there was no significant difference with the control. The experiments showed that doses of 200 and 300 Gy eliminated the mite populations of acaricide resistant and susceptible strains of T. urticae, in a period of ten days. The dose of 100 Gy did not lead to total elimination of the mite populations, but reduced

Effect of gamma radiation on the toxicity of milbemectin and chlorfenapyr in acaricide resistant and susceptible strains of Tetranychus urticae Koch (Acari: Tetranychidae)

International Nuclear Information System (INIS)

Nicastro, Roberto L.; Arthur, Valter; Machi, Andre R.; Sato, Mario E.

2011-01-01

The spider mite Tetranychus urticae Koch is considered one of the most important phytophagous mites, causing considerable damage in several agricultural crops. The aim of this study was to evaluate the effect of gamma radiation on the toxicity of the acaricides milbemectin and chlorfenapyr in resistant and susceptible strains of T. urticae. The R and S strains for milbemectin and chlorfenapyr were irradiated with gamma radiation at Gamma cell-220 source at doses of 5, 10, 20, 40 e 80 Gy. Five concentrations of milbemectin and chlorfenapyr were evaluated, making applications 24 hours after irradiation. Mites of the controls were sprayed with the same acaricide concentrations used for the R and S strains but they were not exposed to gamma radiation. Experiments on the effects of gamma radiation on the growth rates of mites for acaricide resistant and susceptible strains of T. urticae were also carried out. Tests with the Milbemectin S strain showed an increased susceptibility to the acaricide milbemectin, when the mites were irradiated (20 Gy), in comparison with the control (non irradiated mites). For the Milbemectin R strain, there was no significant influence of gamma irradiation on the toxicity of milbemectin to the mites of this strain. For the Chlorfenapyr S strain, the effect of gamma radiation was similar to that observed for Milbemectin S strain, with increased toxicity of chlorfenapyr to the mites of this susceptible strain. In the case of the Chlorfenapyr R strain, the mites exposed to gamma radiation showed to be more tolerant to chlorfenapyr, considering the LC 10 values. The same trend was observed for the LC 50 values, however, there was no significant difference with the control. The experiments showed that doses of 200 and 300 Gy eliminated the mite populations of acaricide resistant and susceptible strains of T. urticae, in a period of ten days. The dose of 100 Gy did not lead to total elimination of the mite populations, but reduced significantly

Comparison of the adhesion ability of Candida albicans strains to ...

African Journals Online (AJOL)

The purpose of the present study is to investigate the ability of oral Candida albicans strains to adhere to Caco-2 and Hep-2 epithelial cells, to produce slime using Congo red and Safranin methods and to form a biofilm on polymethylmethacrylate. A total of 20 C. albicans strains were tested in the present work. The biofilm ...

Total lymphoid irradiation

International Nuclear Information System (INIS)

Sutherland, D.E.; Ferguson, R.M.; Simmons, R.L.; Kim, T.H.; Slavin, S.; Najarian, J.S.

1983-01-01

Total lymphoid irradiation by itself can produce sufficient immunosuppression to prolong the survival of a variety of organ allografts in experimental animals. The degree of prolongation is dose-dependent and is limited by the toxicity that occurs with higher doses. Total lymphoid irradiation is more effective before transplantation than after, but when used after transplantation can be combined with pharmacologic immunosuppression to achieve a positive effect. In some animal models, total lymphoid irradiation induces an environment in which fully allogeneic bone marrow will engraft and induce permanent chimerism in the recipients who are then tolerant to organ allografts from the donor strain. If total lymphoid irradiation is ever to have clinical applicability on a large scale, it would seem that it would have to be under circumstances in which tolerance can be induced. However, in some animal models graft-versus-host disease occurs following bone marrow transplantation, and methods to obviate its occurrence probably will be needed if this approach is to be applied clinically. In recent years, patient and graft survival rates in renal allograft recipients treated with conventional immunosuppression have improved considerably, and thus the impetus to utilize total lymphoid irradiation for its immunosuppressive effect alone is less compelling. The future of total lymphoid irradiation probably lies in devising protocols in which maintenance immunosuppression can be eliminated, or nearly eliminated, altogether. Such protocols are effective in rodents. Whether they can be applied to clinical transplantation remains to be seen

Buying food on sale: a mixed methods study with shoppers at an urban supermarket, Philadelphia, Pennsylvania, 2010-2012.

Science.gov (United States)

Phipps, Etienne J; Kumanyika, Shiriki K; Stites, Shana D; Singletary, S Brook; Cooblall, Clarissa; DiSantis, Katherine Isselmann

2014-09-04

The obesity epidemic has drawn attention to food marketing practices that may increase the likelihood of caloric overconsumption and weight gain. We explored the associations of discounted prices on supermarket purchases of selected high-calorie foods (HCF) and more healthful, low-calorie foods (LCF) by a demographic group at high risk of obesity. Our mixed methods design used electronic supermarket purchase data from 82 low-income (primarily African American female) shoppers for households with children and qualitative data from focus groups with demographically similar shoppers. In analyses of 6,493 food purchase transactions over 65 weeks, the odds of buying foods on sale versus at full price were higher for grain-based snacks, sweet snacks, and sugar-sweetened beverages (odds ratios: 6.6, 5.9, and 2.6, respectively; all P snacks. The odds of buying foods on sale versus full price were not higher for any of any of the LCF (P ≥ .07). Without controlling for quantities purchased, we found that spending increased as percentage saved from the full price increased for all HCF and for fruits and vegetables (P ≤ .002). Focus group participants emphasized the lure of sale items and took advantage of sales to stock up. Strategies that shift supermarket sales promotions from price reductions for HCF to price reductions for LCF might help prevent obesity by decreasing purchases of HCF.

Total quality control: the deming management philosophy applied to nuclear power plants

International Nuclear Information System (INIS)

Heising, C.D.; Wetherell, D.L.; Melhem, S.A.; Sato, M.

1987-01-01

In recent years, a call has come for the development of inherently safe nuclear reactor systems that cannot have large-scale accidents. In the search for the perfect inherently safe reactor system, some are calling for the institution of computerized automated control of reactors eliminating most human operators from the control room. A different approach to the problem of the control of inherently safe reactors is that both future and present nuclear power plants need to institute total quality control (TQC) to plant operations and management. The Deming management philosophy of TQC has been implemented in a wide range of industries - particularly in Japan and the US. Specific attention is given, however, to TQC implementation in the electric power industry as applied to nuclear plants. The Kansai Electric Power Company and Florida Power and Light Company have recently implemented TQC. Statistical quality control methods have been applied to monitor and control reactor variables (for example, to the steam generator water level important to start-up operations of pressurized water reactors)

Strain typing of acetic acid bacteria responsible for vinegar production by the submerged elaboration method.

Science.gov (United States)

Fernández-Pérez, Rocío; Torres, Carmen; Sanz, Susana; Ruiz-Larrea, Fernanda

2010-12-01

Strain typing of 103 acetic acid bacteria isolates from vinegars elaborated by the submerged method from ciders, wines and spirit ethanol, was carried on in this study. Two different molecular methods were utilised: pulsed field gel electrophoresis (PFGE) of total DNA digests with a number of restriction enzymes, and enterobacterial repetitive intergenic consensus (ERIC) - PCR analysis. The comparative study of both methods showed that restriction fragment PFGE of SpeI digests of total DNA was a suitable method for strain typing and for determining which strains were present in vinegar fermentations. Results showed that strains of the species Gluconacetobacter europaeus were the most frequent leader strains of fermentations by the submerged method in the studied vinegars, and among them strain R1 was the predominant one. Results showed as well that mixed populations (at least two different strains) occurred in vinegars from cider and wine, whereas unique strains were found in spirit vinegars, which offered the most stressing conditions for bacterial growth. Copyright © 2010 Elsevier Ltd. All rights reserved.

Influence of Environmental Parameters on Trichoderma Strains with Biocontrol Potential

Directory of Open Access Journals (Sweden)

Zsuzsanna Antal

2003-01-01

Full Text Available Several mycoparasitic strains belonging to the filamentous fungal genus Trichoderma are promising candidates for the biological control of plant pathogenic fungi. When planning the application of antagonistic Trichoderma strains for the purposes of biological control, it is very important to consider the environmental parameters affecting the biocontrol agents in the soil. A series of abiotic and biotic environmental parameters has an influence on the biocontrol efficacy of Trichoderma. Some important parameters to be considered are the effects of temperature, water potential and pH, and the presence of pesticides, metal ions and antagonistic bacteria in the soil. Most of the Trichoderma strains are mesophilic. Low temperatures in winter may cause a problem during biological control by influencing the activity of the biocontrol agents. Another problem emerging during the application of Trichoderma strains as biocontrol agents is that they cannot tolerate dry conditions, however, we may need biocontrol agents against plant pathogenic fungi which are able to grow and cause disease even in dry soils. The pH characteristics of the soil also belong to the most important environmental parameters affecting the activities of mycoparasitic Trichoderma strains. Within the frames of a complex integrated plant protection strategy, we may have to combine Trichoderma strains with chemical pesticides or metal compounds, therefore it is important to collect information about the effects of pesticides and metal ions on the biocontrol strains. Antagonistic soil bacteria may also have negative effects on the biocontrol abilities of Trichoderma strains, therefore it may be advantageous if a biocontrol strain possesses bacterium- degrading abilities as well. This review will discuss the literature about the influence of temperature, water potential, pH, pesticides, metal ions and antagonistic bacteria on mycoparasitic Trichoderma strains including the results of our

Misfit Strain in Superlattices Controlling the Electron-Lattice Interaction via Micro strain in Active Layers

International Nuclear Information System (INIS)

Poccia, N.; Ricci, A.; Bianconi, N.

2010-01-01

High-temperature superconductivity (HTS) emerges in quite different electronic materials: cuprates, diborides, and iron-pnictide superconductors. Looking for unity in the diversity we find in all these materials a common lattice architecture: they are practical realizations of heterostructures at atomic limit made of superlattices of metallic active layers intercalated by spacers as predicted in 1993 by one of us. The multilayer architecture is the key feature for the presence of electronic topological transitions where the Fermi surface of one of the subbands changes dimensionality. The superlattice misfit strain η between the active and spacer layers is shown to be a key variable to drive the system to the highest critical temperature Tc that occurs at a particular point of the 3D phase diagram Tc(θ, η) where d is the charge transfer or doping. The plots of Tc as a function of misfit strain at constant charge transfer in cuprates show a first-order quantum critical phase transition where an itinerant striped magnetic phase competes with superconductivity in the proximity of a structural phase transition, that is, associated with an electronic topological transition. The shape resonances in these multi gap superconductors is associated with the maximum Tc.

Job Strain and Cognitive Decline: A Prospective Study of the Framingham Offspring Cohort

Directory of Open Access Journals (Sweden)

W Agbenyikey

2015-04-01

Full Text Available Background: Workplace stress is known to be related with many behavioral and disease outcomes. However, little is known about its prospective relationship with measures of cognitive decline. Objective: To investigate the association of job strain, psychological demands and job control on cognitive decline. Methods: Participants from Framingham Offspring cohort (n=1429, were assessed on job strain, and received neuropsychological assessment approximately 15 years and 21 years afterwards. Results: High job strain and low control were associated with decline in verbal learning and memory. Job strain was associated with decline in word recognition skills. Active job and passive job predicted decline in verbal learning and memory relative to low strain jobs in the younger subgroup. Active job and demands were positively associated with abstract reasoning skills. Conclusions: Job strain and job control may influence decline in cognitive performance.

Effect of weed control treatments on total leaf area of plantation black walnut (Juglans nigra)

Science.gov (United States)

Jason Cook; Michael R. Saunders

2013-01-01

Determining total tree leaf area is necessary for describing tree carbon balance, growth efficiency, and other measures used in tree-level and stand-level physiological growth models. We examined the effects of vegetation control methods on the total leaf area of sapling-size plantation black walnut trees using allometric approaches. We found significant differences in...

Effects of strain and strain-induced α′-martensite on passive films in AISI 304 austenitic stainless steel

International Nuclear Information System (INIS)

Lv, Jinlong; Luo, Hongyun

2014-01-01

In this paper, the effects of strain and heat treatment on strain-induced α′-martensite of AISI 304 stainless steel tubes were measured by X-ray diffraction. Moreover, the effects of strain and content of α′-martensite on passivated property on the surface of the material in borate buffer solution were evaluated by electrochemical technique. The results showed that the volume fraction of α′-martensite increased gradually with the increase of tensile strain for as-received and solid solution samples. However, α′-martensite in as-received sample was more than that in the solid solution sample. The electrochemical impedance spectroscopy results showed that the solid solution treatment improved corrosion resistance of the steel, especially for samples with small strain. Moreover, acceptor densities were always higher than donor densities for as-received and solid solution samples. With the increase of strain, the increase tendency of acceptor density was more significant than that of donor density. We also found that the total density of the acceptor and donor almost increased linearly with the increase of α′-martensite. The present results indicated that the increased acceptor density might lead to the decreased corrosion resistance of the steel. - Highlights: • The solid solution treatment improved corrosion resistance of the stainless steel. • The deteriorated passivated property after strain could be attributed to the increased acceptor density. • The α′-martensite reduced corrosion resistance of the stainless steel

Lifetime total and beverage specific - alcohol intake and prostate cancer risk: a case-control study

Directory of Open Access Journals (Sweden)

Carruba Giuseppe

2004-12-01

Full Text Available Abstract Background We investigated lifetime alcohol consumption and prostate cancer risk in a case-control study conducted in Buffalo, NY (1998–2001. Methods The study included 88 men, aged 45 to 85 years with incident, histologically-confirmed prostate cancer and 272 controls. We conducted extensive in-person interviews regarding lifetime alcohol consumption and other epidemiologic data. Results Prostate cancer risk was not associated with lifetime intake of total and beverage specific ethanol. In addition we found no association with number of drinks per day (average drinks per day over the lifetime or drinks per drinking day (average drinks per day on drinking days only over the lifetime. However, we observed an inverse association with the total number of drinking years. Men in the lowest tertile of total drinking years had a two-fold prostate cancer risk than men in the highest tertile (OR 2.16, 95% CI 0.98–4.78, p for trend Conclusion Our results suggest that alcohol intake distribution across lifetime may play a more important role in prostate cancer etiology than total lifetime consumption.

Liposomal bupivacaine versus traditional bupivacaine for pain control after total hip arthroplasty

Science.gov (United States)

Ma, Ting-Ting; Wang, Yu-Hui; Jiang, Yun-Feng; Peng, Cong-Bin; Yan, Chao; Liu, Zi-Gui; Xu, Wei-Xing

2017-01-01

Abstract Background: In the past, the efficacy of local infiltration of liposomal bupivacaine for total hip arthroplasty (THA) patients was in debate. Therefore, this meta-analysis was conducted to determine whether local infiltration of liposomal bupivacaine provides better pain relief after THA. Methods: We searched Web of Science, PubMed, Embase, and the Cochrane Library databases to the April 2017. Any studies comparing liposomal bupivacaine and traditional bupivacaine were included in our meta-analysis. The outcomes included visual analog scale (VAS) at 24, 48, and 72 hours, total morphine consumption at 24 hours, and the length of hospital stay. We assessed the pooled data using a random-effect model. Results: Six studies were finally included in this meta-analysis. Our pooled data analysis demonstrated that liposomal bupivacaine was more effective than the traditional bupivacaine in terms of VAS at 24 hours (P  =  .018) and the length of hospital stay (P  =  .000). There was no significant difference in terms of the VAS at 48 and 72 hours and total morphine consumption at 24 hours (P >.05). Conclusion: Compared with the traditional bupivacaine, liposomal bupivacaine shows better pain control at 24 hours and reduces the length of hospital stay after THA. Its economic costs must be assessed in multimodal center randomized controlled trials when being recommended as a long-acting alternative analgesic agent for a THA patient. PMID:28640101

Thermoresistance in radioresistant strains of 'Drosophila nebulosa'

International Nuclear Information System (INIS)

Kratz, F.L.

1977-01-01

The detection of thermoresistance in radioresistant strains of 'D. nebulosa' is described, as well as some conclusions on the genetic nature of these differences are presented. The strains used in this experiment were MF 204, from 'Morro de Ferro', in Pocos de Caldas (MG) (one of the biggest radioactive anomalies in the world) whose radioresistance is due to its additive genetic components (Kratz, 1973 and 1975); 85(87) R, an induced radioresistant strain; and MF K a control 'pooled' strain obtained near 'Morro do Ferro'. Survival tests, 72 hours after temperature shocks, performed in the interval of 36 0 C to 39 0 C showed a decreasing gradient of thermoresistance with the following regression coefficients: MF 204 b= - 5,4; 85(87)R b= - 7,2 and MF K b= - 7,9. Bifactorial analysis (strains and sexes) performed at 38 0 C and 39 0 C confirmed differences among strains (P [pt

In vivo and in vitro control activity of plant essential oils against three strains of Aspergillus niger.

Science.gov (United States)

Kumar, Peeyush; Mishra, Sapna; Kumar, Atul; Kumar, Sanjeev; Prasad, Chandra Shekhar

2017-09-01

Contamination of environment and food from the prevalent spores and mycotoxins of Aspergillus niger has led to several diseases in humans and other animals. The present study investigated the control activity of plant essential oils against three strains of A. niger. In the elaborate assays done through microdilution plate assay and agar disk diffusion assay in the lab condition and in vivo assay on the stored wheat grains, the essential oil of Thymus vulgaris depicted overall superior efficacy. In microdilution plate assay, the oil of Anethum graveolens showed best fungistatic activity, while best fungicidal activity was depicted by Syzygium aromaticum oil. The oil of T. vulgaris showed moderate control efficacy against A. niger strains with its antifungal activity resulting mainly due to killing of microorganism rather than growth inhibition. In agar disk diffusion assay, T. vulgaris oil with a zone of inhibition (ZOI) of 23.3-61.1% was the most effective fungicide. The in vivo assay to evaluate the protection efficacy of oils for stored wheat grains against A. niger (AN1) revealed T. vulgaris (90.5-100%) to be the best control agent, followed by the oil of S. aromaticum (61.9-100%). The GC-MS analysis of T. vulgaris oil indicated the presence of thymol (39.11%), γ-terpinene (19.73%), o-cymene (17.21%), and β-pinene (5.38%) as major oil components. Phytotoxic effects of the oils on wheat seeds showed no significant phytotoxic effect of oils in terms of seed germination or seedling growth. The results of the study demonstrated control potentiality of essential oils for the protection of stored wheat against A. niger with prospect for development of eco-friendly antifungal products.

A randomised, controlled clinical study on total hip arthroplasty using 4 different bearings

DEFF Research Database (Denmark)

Borgwardt, Arne; Zerahn, Bo; Fabricius, Sandra D

2017-01-01

PURPOSE: To compare 4 different bearings in total hip arthroplasty (THA) in a randomised controlled clinical study on clinical performance. METHODS: 393 patients with osteoarthritis of the hip or avascular necrosis were included and allocated to 1 of the head-and-cup couples zirconia...

Cashew consumption reduces total and LDL cholesterol: a randomized, crossover, controlled-feeding trial.

Science.gov (United States)

Mah, Eunice; Schulz, Jacqueline A; Kaden, Valerie N; Lawless, Andrea L; Rotor, Jose; Mantilla, Libertie B; Liska, DeAnn J

2017-05-01

Background: Cashews are the third most-consumed tree nut in the United States and are abundant with monounsaturated fatty acids and polyunsaturated fatty acids, which are associated with reduced cardiovascular disease risk. Although a qualified Food and Drug Administration health claim exists for nuts and heart health, cashews have been exempt from its use because cashews exceed the disqualifying amount of saturated fatty acids. Approximately one-third of the saturated fat in cashews is stearic acid, which is relatively neutral on blood lipids, thereby suggesting that cashews could have effects that are similar to those of other nuts. However, clinical data on cashews and blood lipids have been limited. Objective: We investigated the effect of reasonable intakes of cashews on serum lipids in adults with or at risk of high LDL cholesterol. Design: In a randomized, crossover, isocaloric, controlled-feeding study, 51 men and women (aged 21-73 y) with a median LDL-cholesterol concentration of 159 mg/dL (95% CI: 146, 165 mg/dL) at screening consumed typical American diets with cashews (28-64 g/d; 50% of kilocalories from carbohydrate, 18% of kilocalories from protein, and 32% of kilocalories from total fat) or potato chips (control; 54% of kilocalories from carbohydrate, 18% of kilocalories from protein, and 29% of kilocalories from total fat) for 28 d with a ≥2-wk washout period. Results: Consumption of the cashew diet resulted in a significantly greater median change from baseline (compared with the control, all P cholesterol [-3.9% (95% CI: -9.3%, 1.7%) compared with 0.8% (95% CI: -1.5%, 4.5%), respectively], LDL cholesterol [-4.8% (95% CI: -12.6%, 3.1%) compared with 1.2% (95% CI: -2.3%, 7.8%), respectively], non-HDL cholesterol [-5.3% (95% CI: -8.6%, 2.1%) compared with 1.7% (95% CI: -0.9%, 5.6%), respectively], and the total-cholesterol:HDL-cholesterol ratio [-0.0% (95% CI: -4.3%, 4.8%) compared with 3.4% (95% CI: 0.6%, 5.2%), respectively]. There were no

Antagonistic Activities of Bacillus spp. Strains Isolated from Tidal Flat Sediment Towards Anthracnose Pathogens Colletotrichum acutatum and C. gloeosporioides in South Korea.

Science.gov (United States)

Han, Joon-Hee; Shim, Hongsik; Shin, Jong-Hwan; Kim, Kyoung Su

2015-06-01

Anthracnose is a fungal disease caused by Colletotrichum species that is detrimental to numerous plant species. Anthracnose control with fungicides has both human health and environmental safety implications. Despite increasing public concerns, fungicide use will continue in the absence of viable alternatives. There have been relatively less efforts to search antagonistic bacteria from mudflats harboring microbial diversity. A total of 420 bacterial strains were isolated from mudflats near the western sea of South Korea. Five bacterial strains, LB01, LB14, HM03, HM17, and LB15, were characterized as having antifungal properties in the presence of C. acutatum and C. gloeosporioides. The three Bacillus atrophaeus strains, LB14, HM03, and HM17, produced large quantities of chitinase and protease enzymes, whereas the B. amyloliquefaciens strain LB01 produced protease and cellulase enzymes. Two important antagonistic traits, siderophore production and solubilization of insoluble phosphate, were observed in the three B. atrophaeus strains. Analyses of disease suppression revealed that LB14 was most effective for suppressing the incidence of anthracnose symptoms on pepper fruits. LB14 produced antagonistic compounds and suppressed conidial germination of C. acutatum and C. gloeosporioides. The results from the present study will provide a basis for developing a reliable alternative to fungicides for anthracnose control.

Antagonistic Activities of Bacillus spp. Strains Isolated from Tidal Flat Sediment Towards Anthracnose Pathogens Colletotrichum acutatum and C. gloeosporioides in South Korea

Directory of Open Access Journals (Sweden)

Joon-Hee Han

2015-06-01

Full Text Available Anthracnose is a fungal disease caused by Colletotrichum species that is detrimental to numerous plant species. Anthracnose control with fungicides has both human health and environmental safety implications. Despite increasing public concerns, fungicide use will continue in the absence of viable alternatives. There have been relatively less efforts to search antagonistic bacteria from mudflats harboring microbial diversity. A total of 420 bacterial strains were isolated from mudflats near the western sea of South Korea. Five bacterial strains, LB01, LB14, HM03, HM17, and LB15, were characterized as having antifungal properties in the presence of C. acutatum and C. gloeosporioides. The three Bacillus atrophaeus strains, LB14, HM03, and HM17, produced large quantities of chitinase and protease enzymes, whereas the B. amyloliquefaciens strain LB01 produced protease and cellulase enzymes. Two important antagonistic traits, siderophore production and solubilization of insoluble phosphate, were observed in the three B. atrophaeus strains. Analyses of disease suppression revealed that LB14 was most effective for suppressing the incidence of anthracnose symptoms on pepper fruits. LB14 produced antagonistic compounds and suppressed conidial germination of C. acutatum and C. gloeosporioides. The results from the present study will provide a basis for developing a reliable alternative to fungicides for anthracnose control.

Faulting of rocks in three-dimensional strain fields I. Failure of rocks in polyaxial, servo-control experiments

Science.gov (United States)

Reches, Z.; Dieterich, J.H.

1983-01-01

The dependence of the number of sets of faults and their orientation on the intermediate strain axis is investigated through polyaxial tests, reported here, and theoretical analysis, reported in an accompanying paper. In the experiments, cubic samples of Berea sandstone, Sierra-White and Westerly granites, and Candoro and Solnhofen limestones were loaded on their three pairs of faces by three independent, mutually perpendicular presses at room temperature. Two of the presses were servo-controlled and applied constant displacement rates throughout the experiment. Most samples display three or four sets of faults in orthorhombic symmetry. These faults form in several yielding events that follow a stage of elastic deformation. In many experiments, the maximum and the intermediate compressive stresses interchange orientations during the yielding events, where the corresponding strains are constant. The final stage of most experiments is characterized by slip along the faults. ?? 1983.

Control of protein synthesis in Escherichia coli: strain differences in control of translational initiation after energy source shift-down.

OpenAIRE

Jacobson, L A; Jen-Jacobson, L

1980-01-01

We have studied the parameters of protein synthesis in a number of Escherichia coli strains after a shift-down from glucose-minimal to succinate-minimal medium. One group of strains, including K-12(lambda) (ATCC 10798) and NF162, showed a postshift translational yield of 50 to 65% and a 2- to 2.5-fold increase in the functional lifetime of general messenger ribonucleic acid. There was no change in the lag time for beta-galactosidase induction in these strains after the shift-down. A second gr...

Associations between Mycobacterium tuberculosis Strains and Phenotypes

Science.gov (United States)

Brown, Timothy; Nikolayevskyy, Vladyslav; Velji, Preya

2010-01-01

To inform development of tuberculosis (TB) control strategies, we characterized a total of 2,261 Mycobacterium tuberculosis complex isolates by using multiple phenotypic and molecular markers, including polymorphisms in repetitive sequences (spoligotyping and variable-number tandem repeats [VNTRs]) and large sequence and single-nucleotide polymorphisms. The Beijing family was strongly associated with multidrug resistance (p = 0.0001), and VNTR allelic variants showed strong associations with spoligotyping families: >5 copies at exact tandem repeat (ETR) A, >2 at mycobacterial interspersed repetitive unit 24, and >3 at ETR-B associated with the East African–Indian and M. bovis strains. All M. tuberculosis isolates were differentiated into 4 major lineages, and a maximum parsimony tree was constructed suggesting a more complex phylogeny for M. africanum. These findings can be used as a model of pathogen global diversity. PMID:20113558

Using Ring Strain to Control 4π-Electrocyclization Reactions: Torquoselectivity in Ring Closing of Medium-Ring Dienes and Ring Opening of Bicyclic Cyclobutenes.

Science.gov (United States)

Boon, Byron A; Green, Aaron G; Liu, Peng; Houk, K N; Merlic, Craig A

2017-05-05

Syntheses of strained cyclic dienes were accomplished via palladium(II)-catalyzed oxidative cyclizations of terminal bis(vinylboronate esters). The reactions generate strained (E,E)-1,3-dienes that undergo spontaneous 4π-electrocyclizations to form bicyclic cyclobutenes. Formation of the cyclobutenes is driven by the strain in the medium-ring (E,E)-1,3-diene intermediate. Thermal ring openings of the cyclobutenes give (Z,Z)-1,3-diene products, again for thermodynamic reasons. DFT calculations verified the thermodynamic versus kinetic control of the reactions, and kinetic studies are in excellent agreement with the calculated energy changes. An extension of the tandem coupling/4π-electrocyclization pathway was demonstrated by a palladium(II)-catalyzed oxidative homocoupling/8π-electrocyclization cascade.

Post-UV colony-forming ability of normal fibroblast strains and of the xeroderma pigmentosum group G strain

International Nuclear Information System (INIS)

Barrett, S.F.; Tarone, R.E.; Moshell, A.N.; Ganges, M.B.; Robbins, J.H.

1981-01-01

In xeroderma pigmentosum, an inherited disorder of defective DNA repair, post-uv colony-forming ability of fibroblasts from patients in complementation groups A through F correlates with the patients' neurological status. The first xeroderma pigmentosum patient assigned to the recently discovered group G had the neurological abnormalities of XP. Researchers have determined the post-uv colony-forming ability of cultured fibroblasts from this patient and from 5 more control donors. Log-phase fibroblasts were irradiated with 254 nm uv light from a germicidal lamp, trypsinized, and replated at known densities. After 2 to 4 weeks' incubation the cells were fixed, stained and scored for colony formation. The strains' post-uv colony-forming ability curves were obtained by plotting the log of the percent remaining post-uv colony-forming ability as a function of the uv dose. The post-uv colony-forming ability of 2 of the 5 new normal strains was in the previously defined control donor zone, but that of the other 3 extended down to the level of the most resistant xeroderma pigmentosum strain. The post-uv colony-forming ability curve of the group G fibroblasts was not significantly different from the curves of the group D fibroblast strains from patients with clinical histories similar to that of the group G patient

Effectiveness of composts and Trichoderma strains for control of Fusarium wilt of tomato

Directory of Open Access Journals (Sweden)

Yousra TAGHDI

2015-09-01

Full Text Available Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (FOL is a major limiting disease in tomato production in Morocco. Commercial and locally produced Moroccan composts and peat were found to reduce Fusarium wilt in tomato plants. We explored the presence of Trichoderma strains in these materials, and in six soils sampled in the North West of Morocco, where a low incidence of Fusarium wilt had been previously observed. The most abundant Trichoderma-like fungus was selected from each soil, compost or peat sample. Twelve Trichoderma strains were isolated and identified molecularly. Trichoderma asperellum CT9 and Trichoderma virens ST11 showed the greatest overall antagonistic activity against FOL, Rhizoctonia solani, Botrytis cinerea and Pythium ultimum. The three strains evaluated in in planta tests, CT9, ST11 and T. virens ST10, reduced tomato Fusarium wilt, and strain ST11  also promoted growth of tomato plants.

Differential expression of glutathione s-transferase enzyme in different life stages of various insecticide-resistant strains of Anopheles stephensi: a malaria vector.

Science.gov (United States)

Sanil, D; Shetty, V; Shetty, N J

2014-06-01

Interest in insect glutathione s-transferases (GSTs) has primarily focused on their role in insecticide resistance. These play an important role in biotransformation and detoxification of many different xenobiotic and endogenous substances including insecticides. The GST activity among 10 laboratory selected insecticide resistant and susceptible/control strains of Anopheles stephensi was compared using the substrates 1-chloro-2,4-dinitrobenzene (CDNB). The difference in the GST activities of different life stages of diverse insecticide resistant strains was compared and presented. About 100 larvae, pupae, adult males, adult females and eggs (100 μg in total weight) were collected and used for the experiment. The extracts were prepared from each of the insecticide-resistant strains and control. Protein contents of the enzyme homogenate and GST activities were determined. Deltamethrin and cyfluthrin-resistant strains of An. stephensi showed significantly higher GST activity. Larvae and pupae of DDT-resistant strain showed peak GST activity followed by the propoxur-resistant strain. On contrary, the GST activity was found in reduced quantity in alphamethrin, bifenthrin, carbofuran and chloropyrifos resistant strains. Adults of either sexes showed higher GST activity in mosquito strain resistant to organophosphate group of insecticides namely, temephos and chloropyrifos. The GST activity was closely associated with almost all of the insecticides used in the study, strengthening the fact that one of the mechanisms associated with resistance includes an increase of GST activity. This comparative data on GST activity in An. stephensi can be useful database to identify possible underlying mechanisms governing insecticide-resistance by GSTs.

Scientific Opinion on the essential composition of total diet replacements for weight control

DEFF Research Database (Denmark)

Tetens, Inge

2015-01-01

or authoritative bodies. Derived from the minimum content of macronutrients, the Panel proposed a minimum energy content of total diet replacements for weight control of 2 510 kJ/day (600 kcal/day). The Panel also advised on potential conditions and restrictions of use for these products....

Genomic Changes in an Attenuated ZB Strain of Foot-and-Mouth Disease Virus Serotype Asia1 and Comparison with Its Virulent Parental Strain

Directory of Open Access Journals (Sweden)

Aiguo Xin

2014-01-01

Full Text Available The molecular basis of attenuation of foot-and-mouth disease virus (FMDV serotype Asia1 ZB strain remains unknown. To understand the genetic changes of attenuation, we compared the entire genomes of three different rabbit-passaged attenuated ZB strains (ZB/CHA/58(att, ZBRF168, and ZBRF188 and their virulent parental strains (ZBCF22 and YNBS/58. The results showed that attenuation may be brought about by 28 common amino acid substitutions in the coding region, with one nucleotide point mutation in the 5′-untranslated region (5′-UTR and another one in the 3′-UTR. In addition, a total of 21 nucleotides silent mutations had been found after attenuation. These substitutions, alone or in combination, may be responsible for the attenuated phenotype of the ZB strain in cattle. This will contribute to elucidation of attenuating molecular basis of the FMDV ZB strain.

Strain response of stretchable micro-electrodes: Controlling sensitivity with serpentine designs and encapsulation

International Nuclear Information System (INIS)

Gutruf, Philipp; Walia, Sumeet; Nur Ali, Md; Sriram, Sharath; Bhaskaran, Madhu

2014-01-01

The functionality of flexible electronics relies on stable performance of thin film micro-electrodes. This letter investigates the behavior of gold thin films on polyimide, a prevalent combination in flexible devices. The dynamic behavior of gold micro-electrodes has been studied by subjecting them to stress while monitoring their resistance in situ. The shape of the electrodes was systematically varied to examine resistive strain sensitivity, while an additional encapsulation was applied to characterize multilayer behavior. The realized designs show remarkable tolerance to repetitive strain, demonstrating that curvature and encapsulation are excellent approaches for minimizing resistive strain sensitivity to enable durable flexible electronics

Tranexamic acid for control of blood loss in bilateral total knee replacement in a single stage

Directory of Open Access Journals (Sweden)

Mandeep S Dhillon

2011-01-01

Full Text Available Background: Tranexamic acid (TEA reduces blood loss and red cell transfusions in patients undergoing unilateral total knee arthroplasty (TKA. However, there is not much literature regarding the use of TEA in patients undergoing bilateral TKA in a single stage and the protocols for administration of TEA in such patients are ill-defined. Materials and Methods: We carried out a case control study evaluating the effect of TEA on postoperative hemoglobin (Hb, total drain output, and number of blood units transfused in 52 patients undergoing bilateral TKA in a single stage, and compared it with 56 matched controls who did not receive TEA. Two doses of TEA were administered in doses of 10 mg / kg each (slow intravenous (IV infusion, with the first dose given just before tourniquet release of the first knee and the second dose three hours after the first one. Results: A statistically significant reduction in the total drain output and requirement of allogenic blood transfusion in cases who received TEA, as compared to the controls was observed. The postoperative Hb and Hb at the time of discharge were found to be lower in the control group, and this result was found to be statistically significant. Conclusion: TEA administered in patients undergoing single stage bilateral TKA helped reduce total blood loss and decreased allogenic blood transfusion requirements. This might be particularly relevant, where facilities such as autologous reinfusion might not be available.

Control of superconductivity by means of electric-field-induced strain in superconductor/piezoelectric hybrids

Science.gov (United States)

Stamopoulos, D.; Zeibekis, M.; Zhang, S. J.

2018-01-01

The controlled modification of superconductivity by any means, specifically in hybrid systems, has attracted much interest in the recent decades. Here, we present experimental data and phenomenological modeling on the control of TC of superconducting (SC) Nb thin films, with thickness 3 nm ≤ dN b≤50 nm, under the application of in-plane strain, S(Eex) induced by an external out-of-plane electric field, Eex to piezoelectric (PE) single crystals, namely, ( 1 -x )Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT), with x = 0.27 and 0.31. We report experimental modification of TC of Nb by Eex, accurately described by a phenomenological model that incorporates the constitutive relation S(Eex) of PMN-xPT. The systematic experimental-phenomenological modeling approach introduced here is generic and paves the way for an understanding of the underlying physical mechanisms in any SC/PE hybrid.

Control of total voltage in the large distributed RF system of LEP

CERN Document Server

Ciapala, Edmond

1995-01-01

The LEP RF system is made up of a large number of independent RF units situated around the ring near the interaction points. These have different available RF voltages depending on their type and they may be inactive or unable to provide full voltage for certain periods. The original RF voltage control system was based on local RF unit voltage function generators pre-loaded with individual tables for energy ramping. This was replaced this year by a more flexible global RF voltage control system. A central controller in the main control room has direct access to the units over the LEP TDM system via multiplexers and local serial links. It continuously checks the state of all the units and adjusts their voltages to maintain the desired total voltage under all conditions. This voltage is distributed among the individual units to reduce the adverse effects of RF voltage asymmetry around the machine as far as possible. The central controller is a VME system with 68040 CPU and real time multitasking operating syste...

Whole-Genome Sequence of Pseudomonas graminis Strain UASWS1507, a Potential Biological Control Agent and Biofertilizer Isolated in Switzerland.

Science.gov (United States)

Crovadore, Julien; Calmin, Gautier; Chablais, Romain; Cochard, Bastien; Schulz, Torsten; Lefort, François

2016-10-06

We report here the whole-genome shotgun sequence of the strain UASWS1507 of the species Pseudomonas graminis, isolated in Switzerland from an apple tree. This is the first genome registered for this species, which is considered as a potential and valuable resource of biological control agents and biofertilizers for agriculture. Copyright © 2016 Crovadore et al.

Differential effects of decision latitude and control on the job demands-strain relationship: a cross-sectional survey study among elderly care nursing staff.

Science.gov (United States)

Schmidt, Klaus-Helmut; Diestel, Stefan

2011-03-01

According to the influential Job Demands-Control (JD-C) model developed by Karasek (1979; Karasek and Theorell, 1990), job strain is expected to result from high job demands and low job control as well as an interaction between both job characteristics. Previous research, however, has found such an interaction only rarely or inconsistently.It has been suggested that the conceptualization of the control variable (formerly referred to as decision latitude) may be particularly responsible for the lack of supportive findings. The present study aimed at clarifying this issue by contrasting a focused measure of control with a traditional measure of decision latitude in their relations to job strain of health care workers. The measure of decision latitude encompassed a wide range of job characteristics including control, task variety, and learning opportunities. A cross-sectional questionnaire survey was conducted with job satisfaction, psychosomatic complaints and emotional exhaustion as criterion measures of job strain. A supra-regional organization for residential elderly care with 11 nursing homes located in a federal state in Germany. Questionnaires were distributed to the whole nursing staff, of which 379 filled in the questionnaire during normal working hours (68% participation rate). In addition to confirmatory factor analyses, descriptive statistics, and bivariate correlations, hierarchical multiple regression analyses were performed for testing the corresponding interaction effects. Findings confirmed the assumption that the focused measure of control and the traditional measure of decision latitude represent distinct, yet correlated factors. Furthermore, findings revealed a significant interaction effect between job demands and control on all outcomes considered. By way of contrast, there was no equivalent interaction effect between job demands and decision latitude. In line with the JD-C model, the adverse influence of increasing demands on job satisfaction

Introducing lattice strain to graphene encapsulated in hBN

Science.gov (United States)

Tomori, Hikari; Hiraide, Rineka; Ootuka, Youiti; Watanabe, Kenji; Taniguchi, Takashi; Kanda, Akinobu

Due to the characteristic lattice structure, lattice strain in graphene produces an effective gauge field. Theories tell that by controlling spatial variation of lattice strain, one can tailor the electronic state and transport properties of graphene. For example, under uniaxial local strain, graphene exhibits a transport gap at low energies, which is attractive for a graphene application to field effect devices. Here, we develop a method for encapsulating a strained graphene film in hexagonal boron-nitride (hBN). It is known that the graphene carrier mobility is significantly improved by the encapsulation of graphene in hBN, which has never been applied to strained graphene. We encapsulate graphene in hBN using the van der Waals assembly method. Strain is induced by sandwiching a graphene film between patterned hBN sheets. Spatial variation of strain is confirmed with micro Raman spectroscopy. Transport measurement of encapsulated strained graphene is in progress.

Strain rate effects in stress corrosion cracking

Energy Technology Data Exchange (ETDEWEB)

Parkins, R.N. (Newcastle upon Tyne Univ. (UK). Dept. of Metallurgy and Engineering Materials)

1990-03-01

Slow strain rate testing (SSRT) was initially developed as a rapid, ad hoc laboratory method for assessing the propensity for metals an environments to promote stress corrosion cracking. It is now clear, however, that there are good theoretical reasons why strain rate, as opposed to stress per se, will often be the controlling parameter in determining whether or not cracks are nucleated and, if so, are propagated. The synergistic effects of the time dependence of corrosion-related reactions and microplastic strain provide the basis for mechanistic understanding of stress corrosion cracking in high-pressure pipelines and other structures. However, while this may be readily comprehended in the context of laboratory slow strain tests, its extension to service situations may be less apparent. Laboratory work involving realistic stressing conditions, including low-frequency cyclic loading, shows that strain or creep rates give good correlation with thresholds for cracking and with crack growth kinetics.

Methods for predicting isochronous stress-strain curves

International Nuclear Information System (INIS)

Kiyoshige, Masanori; Shimizu, Shigeki; Satoh, Keisuke.

1976-01-01

Isochronous stress-strain curves show the relation between stress and total strain at a certain temperature with time as a parameter, and they are drawn up from the creep test results at various stress levels at a definite temperature. The concept regarding the isochronous stress-strain curves was proposed by McVetty in 1930s, and has been used for the design of aero-engines. Recently the high temperature characteristics of materials are shown as the isochronous stress-strain curves in the design guide for the nuclear energy equipments and structures used in high temperature creep region. It is prescribed that these curves are used as the criteria for determining design stress intensity or the data for analyzing the superposed effects of creep and fatigue. In case of the isochronous stress-strain curves used for the design of nuclear energy equipments with very long service life, it is impractical to determine the curves directly from the results of long time creep test, accordingly the method of predicting long time stress-strain curves from short time creep test results must be established. The method proposed by the authors, for which the creep constitution equations taking the first and second creep stages into account are used, and the method using Larson-Miller parameter were studied, and it was found that both methods were reliable for the prediction. (Kako, I.)

Strain-tuning of edge magnetism in zigzag graphene nanoribbons.

Science.gov (United States)

Yang, Guang; Li, Baoyue; Zhang, Wei; Ye, Miao; Ma, Tianxing

2017-09-13

Using the determinant quantum Monte-Carlo method, we elucidate the strain tuning of edge magnetism in zigzag graphene nanoribbons. Our intensive numerical results show that a relatively weak Coulomb interaction may induce a ferromagnetic-like behaviour with a proper strain, and the edge magnetism can be enhanced greatly as the strain along the zigzag edge increases, which provides another way to control graphene magnetism even at room temperature.

Temperature affects the morphology and calcification of Emiliania huxleyi strains

Science.gov (United States)

Rosas-Navarro, Anaid; Langer, Gerald; Ziveri, Patrizia

2016-05-01

The global warming debate has sparked an unprecedented interest in temperature effects on coccolithophores. The calcification response to temperature changes reported in the literature, however, is ambiguous. The two main sources of this ambiguity are putatively differences in experimental setup and strain specificity. In this study we therefore compare three strains isolated in the North Pacific under identical experimental conditions. Three strains of Emiliania huxleyi type A were grown under non-limiting nutrient and light conditions, at 10, 15, 20 and 25 °C. All three strains displayed similar growth rate versus temperature relationships, with an optimum at 20-25 °C. Elemental production (particulate inorganic carbon (PIC), particulate organic carbon (POC), total particulate nitrogen (TPN)), coccolith mass, coccolith size, and width of the tube element cycle were positively correlated with temperature over the sub-optimum to optimum temperature range. The correlation between PIC production and coccolith mass/size supports the notion that coccolith mass can be used as a proxy for PIC production in sediment samples. Increasing PIC production was significantly positively correlated with the percentage of incomplete coccoliths in one strain only. Generally, coccoliths were heavier when PIC production was higher. This shows that incompleteness of coccoliths is not due to time shortage at high PIC production. Sub-optimal growth temperatures lead to an increase in the percentage of malformed coccoliths in a strain-specific fashion. Since in total only six strains have been tested thus far, it is presently difficult to say whether sub-optimal temperature is an important factor causing malformations in the field. The most important parameter in biogeochemical terms, the PIC : POC ratio, shows a minimum at optimum growth temperature in all investigated strains. This clarifies the ambiguous picture featuring in the literature, i.e. discrepancies between PIC : POC

Strain-Level Diversity of Secondary Metabolism in Streptomyces albus

Science.gov (United States)

Seipke, Ryan F.

2015-01-01

Streptomyces spp. are robust producers of medicinally-, industrially- and agriculturally-important small molecules. Increased resistance to antibacterial agents and the lack of new antibiotics in the pipeline have led to a renaissance in natural product discovery. This endeavor has benefited from inexpensive high quality DNA sequencing technology, which has generated more than 140 genome sequences for taxonomic type strains and environmental Streptomyces spp. isolates. Many of the sequenced streptomycetes belong to the same species. For instance, Streptomyces albus has been isolated from diverse environmental niches and seven strains have been sequenced, consequently this species has been sequenced more than any other streptomycete, allowing valuable analyses of strain-level diversity in secondary metabolism. Bioinformatics analyses identified a total of 48 unique biosynthetic gene clusters harboured by Streptomyces albus strains. Eighteen of these gene clusters specify the core secondary metabolome of the species. Fourteen of the gene clusters are contained by one or more strain and are considered auxiliary, while 16 of the gene clusters encode the production of putative strain-specific secondary metabolites. Analysis of Streptomyces albus strains suggests that each strain of a Streptomyces species likely harbours at least one strain-specific biosynthetic gene cluster. Importantly, this implies that deep sequencing of a species will not exhaust gene cluster diversity and will continue to yield novelty. PMID:25635820

Establishing quality control ranges for antimicrobial susceptibility testing of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus: a cornerstone to develop reference strains for Korean clinical microbiology laboratories.

Science.gov (United States)

Hong, Sung Kuk; Choi, Seung Jun; Shin, Saeam; Lee, Wonmok; Pinto, Naina; Shin, Nari; Lee, Kwangjun; Hong, Seong Geun; Kim, Young Ah; Lee, Hyukmin; Kim, Heejung; Song, Wonkeun; Lee, Sun Hwa; Yong, Dongeun; Lee, Kyungwon; Chong, Yunsop

2015-11-01

Quality control (QC) processes are being performed in the majority of clinical microbiology laboratories to ensure the performance of microbial identification and antimicrobial susceptibility testing by using ATCC strains. To obtain these ATCC strains, some inconveniences are encountered concerning the purchase cost of the strains and the shipping time required. This study was focused on constructing a database of reference strains for QC processes using domestic bacterial strains, concentrating primarily on antimicrobial susceptibility testing. Three strains (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) that showed legible results in preliminary testing were selected. The minimal inhibitory concentrations (MICs) and zone diameters (ZDs) of eight antimicrobials for each strain were determined according to the CLSI M23. All resulting MIC and ZD ranges included at least 95% of the data. The ZD QC ranges obtained by using the CLSI method were less than 12 mm, and the MIC QC ranges extended no more than five dilutions. This study is a preliminary attempt to construct a bank of Korean QC strains. With further studies, a positive outcome toward cost and time reduction can be anticipated.

Analysis of alternative transportation methods for radioactive materials shipments including the use of special trains for spent fuel and wastes

International Nuclear Information System (INIS)

Smith, D.R.; Luna, R.E.; Taylor, J.M.

1978-01-01

Two studies were completed which evaluate the environmental impact of radioactive material transport. The first was a generic study which evaluated all radioactive materials and all transportation modes; the second addressed spent fuel and fuel-cycle wastes shipped by truck, rail and barge. A portion of each of those studies dealing with the change in impact resulting from alternative shipping methods is presented in this paper. Alternatives evaluated in each study were mode shifts, operational constraints, and, in generic case, changes in material properties and package capabilities. Data for the analyses were obtained from a shipper survey and from projections of shipments that would occur in an equilibrium fuel cycle supporting one hundred 1000-MW(e) reactors. Population exposures were deduced from point source radiation formulae using separation distances derived for scenarios appropriate to each shipping mode and to each exposed population group. Fourteen alternatives were investigated for the generic impact case. All showed relatively minor changes in the overall radiological impact. Since the radioactive material transport is estimated to be fewer than 3 latent cancer fatalities (LCF) for each shipment year (compared to some 300,000 yearly cancer fatalities or 5000 LCF's calculated for background radiation using the same radiological effects model), a 15% decrease caused by shifting from passenger air to cargo air is a relatively small effect. Eleven alternatives were considered for the fuel cycle/special train study, but only one produced a reduction in total special train baseline LCF's (.047) that was larger than 5%

Characterisation of two quorum sensing systems in the endophytic Serratia plymuthica strain G3: differential control of motility and biofilm formation according to life-style.

Science.gov (United States)

Liu, Xiaoguang; Jia, Jinli; Popat, Roman; Ortori, Catherine A; Li, Jun; Diggle, Stephen P; Gao, Kexiang; Cámara, Miguel

2011-02-01

N-acylhomoserine lactone (AHL)-based quorum sensing (QS) systems have been described in many plant-associated Gram-negative bacteria to control certain beneficial phenotypic traits, such as production of biocontrol factors and plant growth promotion. However, the role of AHL-mediated signalling in the endophytic strains of plant-associated Serratia is still poorly understood. An endophytic Serratia sp. G3 with biocontrol potential and high levels of AHL signal production was isolated from the stems of wheat and the role of QS in this isolate was determined. Strain G3 classified as Serratia plymuthica based on 16S rRNA was subjected to phylogenetic analysis. Using primers to conserved sequences of luxIR homologues from the Serratia genus, splIR and spsIR from the chromosome of strain G3 were cloned and sequenced. AHL profiles from strain G3 and Escherichia coli DH5α expressing splI or spsI from recombinant plasmids were identified by liquid chromatography-tandem mass spectrometry. This revealed that the most abundant AHL signals produced by SplI in E. coli were N-3-oxo-hexanoylhomoserine lactone (3-oxo-C6-HSL), N-3-oxo-heptanoylhomoserine lactone (3-oxo-C7-HSL), N-3-hydroxy-hexanoylhomoserine lactone (3-hydroxy-C6-HSL), N-hexanoylhomoserine lactone (C6-HSL), and N-heptanoyl homoserine lactone (C7-HSL); whereas SpsI was primarily responsible for the synthesis of N-butyrylhomoserine lactone (C4-HSL) and N-pentanoylhomoserine lactone (C5-HSL). Furthermore, a quorum quenching analysis by heterologous expression of the Bacillus A24 AiiA lactonase in strain G3 enabled the identification of the AHL-regulated biocontrol-related traits. Depletion of AHLs with this lactonase resulted in altered adhesion and biofilm formation using a microtiter plate assay and flow cells coupled with confocal laser scanning microscopy respectively. This was different from the closely related S. plymuthica strains HRO-C48 and RVH1, where biofilm formation for both strains is AHL

Characterisation of two quorum sensing systems in the endophytic Serratia plymuthica strain G3: differential control of motility and biofilm formation according to life-style

Directory of Open Access Journals (Sweden)

Li Jun

2011-02-01

Full Text Available Abstract Background N-acylhomoserine lactone (AHL-based quorum sensing (QS systems have been described in many plant-associated Gram-negative bacteria to control certain beneficial phenotypic traits, such as production of biocontrol factors and plant growth promotion. However, the role of AHL-mediated signalling in the endophytic strains of plant-associated Serratia is still poorly understood. An endophytic Serratia sp. G3 with biocontrol potential and high levels of AHL signal production was isolated from the stems of wheat and the role of QS in this isolate was determined. Results Strain G3 classified as Serratia plymuthica based on 16S rRNA was subjected to phylogenetic analysis. Using primers to conserved sequences of luxIR homologues from the Serratia genus, splIR and spsIR from the chromosome of strain G3 were cloned and sequenced. AHL profiles from strain G3 and Escherichia coli DH5α expressing splI or spsI from recombinant plasmids were identified by liquid chromatography-tandem mass spectrometry. This revealed that the most abundant AHL signals produced by SplI in E. coli were N-3-oxo-hexanoylhomoserine lactone (3-oxo-C6-HSL, N-3-oxo-heptanoylhomoserine lactone (3-oxo-C7-HSL, N-3-hydroxy-hexanoylhomoserine lactone (3-hydroxy-C6-HSL, N-hexanoylhomoserine lactone (C6-HSL, and N-heptanoyl homoserine lactone (C7-HSL; whereas SpsI was primarily responsible for the synthesis of N-butyrylhomoserine lactone (C4-HSL and N-pentanoylhomoserine lactone (C5-HSL. Furthermore, a quorum quenching analysis by heterologous expression of the Bacillus A24 AiiA lactonase in strain G3 enabled the identification of the AHL-regulated biocontrol-related traits. Depletion of AHLs with this lactonase resulted in altered adhesion and biofilm formation using a microtiter plate assay and flow cells coupled with confocal laser scanning microscopy respectively. This was different from the closely related S. plymuthica strains HRO-C48 and RVH1, where biofilm formation

Strain engineering of topological phase transition in elemental gray tin: Dirac semimetal phase in the missing half of strain spectrum

Science.gov (United States)

Huang, Huaqing; Liu, Feng

Gray tin was previously found to be a strong topological insulator under compressive uniaxial strain. Here, based on effective k . p analysis and first-principles calculations, we discover that gray tin becomes a Dirac semimetal in the other missing half of strain spectrum, under tensile uniaxial strain. In this newly found Dirac semimetal state, two Dirac points which are tunable by tensile [001] strains, lie in the kz axis and Fermi arcs appear in the (100) surface. A large negative magnetoresistance is anticipated in this half of strain spectrum, which shows as a strong signature of the chiral anomaly effect. Comparing to other Dirac semimetal materials, the proposed Dirac semimetal state in the nontoxic elemental gray tin can be more easily manipulated and accurately controlled. We envision that gray tin provides a perfect platform for strain engineering of topological phase transitions by sweeping through the strain spectrum from positive to negative and vice versa. This work was support by DOE-BES (Grant No. DE-FG02-04ER46148).

The Marine Fungi Rhodotorula sp. (Strain CNYC4007 as a Potential Feed Source for Fish Larvae Nutrition

Directory of Open Access Journals (Sweden)

M. Barra

2017-12-01

Full Text Available Fish oil is used in the production of feed for cultured fish owing to its high polyunsaturated fatty acid content (PUFA. The over-exploitation of fisheries and events like “El Niño” are reducing the fish oil supply. Some marine microorganisms are considered potentially as alternative fatty acid sources. This study assesses a strain of Rhodotorula sp. (strain CNYC4007; 27% docosahexaenoic acid (DHA of total fatty acids, as feed for fish larvae. The total length and ribonucleic acid (RNA/deoxyribonucleic acid (DNA ratio of Danio rerio larvae was determined at first feeding at six and 12 days old (post-yolk absorption larvae. Larvae fed with microencapsulated Rhodotorula sp. CNYC4007 had a significantly higher RNA/DNA ratio than control group (C1. At six days post-yolk absorption group, the RNA/DNA ratio of larvae fed with Rhodotorula sp. bioencapsulated in Brachionus sp. was significantly higher than control group fed with a commercial diet high in DHA (C2-DHA. Finally, at 12 days post-yolk absorption, the RNA/DNA ratio was significantly higher in larvae fed with Rhodotorula sp. CNYC4007 and C2-DHA (both bioencapsulated in Artemia sp. nauplii than in control group (C1. These results suggest that Rhodotorula sp. CNYC4007 can be an alternative source of DHA for feeding fish at larval stage, providing a sustainable source of fatty acids.

Tunable strain gauges based on two-dimensional silver nanowire networks

International Nuclear Information System (INIS)

Ho, Xinning; Cheng, Chek Kweng; Tey, Ju Nie; Wei, Jun

2015-01-01

Strain gauges are used in various applications such as wearable strain gauges and strain gauges in airplanes or structural health monitoring. Sensitivity of the strain gauge required varies, depending on the application of the strain gauge. This paper reports a tunable strain gauge based on a two-dimensional percolative network of silver nanowires. By varying the surface coverage of the nanowire network and the waviness of the nanowires in the network, the sensitivity of the strain gauge can be controlled. Hence, a tunable strain gauge can be engineered, based on demands of the application. A few applications are demonstrated. The strain gauge can be adhered to the human neck to detect throat movements and a glove integrated with such a strain gauge can detect the bending of the forefinger. Other classes of two-dimensional percolative networks of one-dimensional materials are also expected to exhibit similar tunable properties. (paper)

Blood volume, blood pressure and total body sodium: internal signalling and output control

DEFF Research Database (Denmark)

Bie, P

2009-01-01

Total body sodium and arterial blood pressure (ABP) are mutually dependent variables regulated by complex control systems. This review addresses the role of ABP in the normal control of sodium excretion (NaEx), and the physiological control of renin secretion. NaEx is a pivotal determinant of ABP......, and under experimental conditions, ABP is a powerful, independent controller of NaEx. Blood volume is a function of dietary salt intake; however, ABP is not, at least not in steady states. A transient increase in ABP after a step-up in sodium intake could provide a causal relationship between ABP...... and the regulation of NaEx via a hypothetical integrative control system. However, recent data show that subtle sodium loading (simulating salty meals) causes robust natriuresis without changes in ABP. Changes in ABP are not necessary for natriuresis. Normal sodium excretion is not regulated by pressure. Plasma...

Haemophilus ducreyi Cutaneous Ulcer Strains Diverged from Both Class I and Class II Genital Ulcer Strains: Implications for Epidemiological Studies.

Directory of Open Access Journals (Sweden)

Dharanesh Gangaiah

2016-12-01

Full Text Available Haemophilus ducreyi has emerged as a major cause of cutaneous ulcers (CU in yaws-endemic regions of the tropics in the South Pacific, South East Asia and Africa. H. ducreyi was once thought only to cause the genital ulcer (GU disease chancroid; GU strains belong to 2 distinct classes, class I and class II. Using whole-genome sequencing of 4 CU strains from Samoa, 1 from Vanuatu and 1 from Papua New Guinea, we showed that CU strains diverged from the class I strain 35000HP and that one CU strain expressed β-lactamase. Recently, the Center for Disease Control and Prevention released the genomes of 11 additional CU strains from Vanuatu and Ghana; however, the evolutionary relationship of these CU strains to previously-characterized CU and GU strains is unknown.We performed phylogenetic analysis of 17 CU and 10 GU strains. Class I and class II GU strains formed two distinct clades. The class I strains formed two subclades, one containing 35000HP and HD183 and the other containing the remainder of the class I strains. Twelve of the CU strains formed a subclone under the class I 35000HP subclade, while 2 CU strains formed a subclone under the other class I subclade. Unexpectedly, 3 of the CU strains formed a subclone under the class II clade. Phylogenetic analysis of dsrA-hgbA-ncaA sequences yielded a tree similar to that of whole-genome phylogenetic tree.CU strains diverged from multiple lineages within both class I and class II GU strains. Multilocus sequence typing of dsrA-hgbA-ncaA could be reliably used for epidemiological investigation of CU and GU strains. As class II strains grow relatively poorly and are relatively more susceptible to vancomycin than class I strains, these findings have implications for methods to recover CU strains. Comparison of contemporary CU and GU isolates would help clarify the relationship between these entities.

Haemophilus ducreyi Cutaneous Ulcer Strains Diverged from Both Class I and Class II Genital Ulcer Strains: Implications for Epidemiological Studies.

Science.gov (United States)

Gangaiah, Dharanesh; Spinola, Stanley M

2016-12-01

Haemophilus ducreyi has emerged as a major cause of cutaneous ulcers (CU) in yaws-endemic regions of the tropics in the South Pacific, South East Asia and Africa. H. ducreyi was once thought only to cause the genital ulcer (GU) disease chancroid; GU strains belong to 2 distinct classes, class I and class II. Using whole-genome sequencing of 4 CU strains from Samoa, 1 from Vanuatu and 1 from Papua New Guinea, we showed that CU strains diverged from the class I strain 35000HP and that one CU strain expressed β-lactamase. Recently, the Center for Disease Control and Prevention released the genomes of 11 additional CU strains from Vanuatu and Ghana; however, the evolutionary relationship of these CU strains to previously-characterized CU and GU strains is unknown. We performed phylogenetic analysis of 17 CU and 10 GU strains. Class I and class II GU strains formed two distinct clades. The class I strains formed two subclades, one containing 35000HP and HD183 and the other containing the remainder of the class I strains. Twelve of the CU strains formed a subclone under the class I 35000HP subclade, while 2 CU strains formed a subclone under the other class I subclade. Unexpectedly, 3 of the CU strains formed a subclone under the class II clade. Phylogenetic analysis of dsrA-hgbA-ncaA sequences yielded a tree similar to that of whole-genome phylogenetic tree. CU strains diverged from multiple lineages within both class I and class II GU strains. Multilocus sequence typing of dsrA-hgbA-ncaA could be reliably used for epidemiological investigation of CU and GU strains. As class II strains grow relatively poorly and are relatively more susceptible to vancomycin than class I strains, these findings have implications for methods to recover CU strains. Comparison of contemporary CU and GU isolates would help clarify the relationship between these entities.

Estimation of strain from piezoelectric effect and domain switching in morphotropic PZT by combined analysis of macroscopic strain measurements and synchrotron X-ray data

International Nuclear Information System (INIS)

Kungl, Hans; Theissmann, Ralf; Knapp, Michael; Baehtz, Carsten; Fuess, Hartmut; Wagner, Susanne; Fett, Theo; Hoffmann, Michael J.

2007-01-01

Morphotropic PZT ceramics are State of the art materials for ferroelectric actuators. Essential performance parameters for these materials are strain and hysteresis. On a microscopic scale the strain provided by an electric field is due to two different mechanisms. The piezoelectric effect causes an elongation of the unit cells, whereas domain switching changes their crystallographic orientation by aligning the polarization axis towards the field direction. A method is outlined to estimate the contribution of the two mechanisms to total strain by combining macroscopic strain measurements and X-ray diffraction (XRD) data. Results from macroscopic measurements of remanent and unipolar strain with the corresponding data on texture, derived from in situ synchrotron radiation XRD patterns, are analyzed and evaluated by a semi-empirical approach. The method was applied to six morphotropic, LaSr doped PZT materials of different Zr/Ti ratios. Results are discussed with respect to the differences between the materials

Genome sequencing and analysis of BCG vaccine strains.

Directory of Open Access Journals (Sweden)

Wen Zhang

Full Text Available BACKGROUND: Although the Bacillus Calmette-Guérin (BCG vaccine against tuberculosis (TB has been available for more than 75 years, one third of the world's population is still infected with Mycobacterium tuberculosis and approximately 2 million people die of TB every year. To reduce this immense TB burden, a clearer understanding of the functional genes underlying the action of BCG and the development of new vaccines are urgently needed. METHODS AND FINDINGS: Comparative genomic analysis of 19 M. tuberculosis complex strains showed that BCG strains underwent repeated human manipulation, had higher region of deletion rates than those of natural M. tuberculosis strains, and lost several essential components such as T-cell epitopes. A total of 188 BCG strain T-cell epitopes were lost to various degrees. The non-virulent BCG Tokyo strain, which has the largest number of T-cell epitopes (359, lost 124. Here we propose that BCG strain protection variability results from different epitopes. This study is the first to present BCG as a model organism for genetics research. BCG strains have a very well-documented history and now detailed genome information. Genome comparison revealed the selection process of BCG strains under human manipulation (1908-1966. CONCLUSIONS: Our results revealed the cause of BCG vaccine strain protection variability at the genome level and supported the hypothesis that the restoration of lost BCG Tokyo epitopes is a useful future vaccine development strategy. Furthermore, these detailed BCG vaccine genome investigation results will be useful in microbial genetics, microbial engineering and other research fields.

Clostridial Strain-Specific Characteristics Associated with Necrotizing Enterocolitis.

Science.gov (United States)

Schönherr-Hellec, Sophia; Klein, Geraldine L; Delannoy, Johanne; Ferraris, Laurent; Rozé, Jean Christophe; Butel, Marie José; Aires, Julio

2018-04-01

We aimed at identifying potential bacterial factors linking clostridia with necrotizing enterocolitis (NEC). We compared the phenotypic traits, stress responses, cellular cytotoxicity, and inflammatory capabilities of the largest collection of Clostridium butyricum and Clostridium neonatale strains isolated from fecal samples of NEC preterm neonates (PN) and control PNs. When strain characteristics were used as explanatory variables, a statistical discriminant analysis allowed the separation of NEC and control strains into separate groups. Strains isolated from NEC PN were characterized by a higher viability at 30°C ( P = 0.03) and higher aerotolerance ( P = 0.01), suggesting that NEC strains may have a competitive and/or survival advantage in the environmental gastrointestinal tract conditions of NEC PN. Heat-treated NEC bacteria induced higher production of interleukin-8 in Caco-2 cells ( P = 0.03), suggesting proinflammatory activity. In vitro , bacteria, bacterial components, and fecal filtrates showed variable cytotoxic effects affecting the cellular network and/or cell viability, without specific association with NEC or control samples. Altogether, our data support the existence of a specific clostridial strain signature associated with NEC. IMPORTANCE Clostridia are part of the commensal microbiota in preterm neonates (PN). However, microbiota analyses by culture and metagenomics have linked necrotizing enterocolitis (NEC) and intestinal colonization with clostridial species. Nevertheless, little is known about the specific characteristics that may be shared by clostridia associated with NEC compared to commensal clostridia. Therefore, our goal was to identify specific bacterial factors linking clostridial strains with NEC. We report the existence of a specific bacterial signature associated with NEC and propose that activation of the innate immune response may be a unifying causative mechanism for the development of NEC independent of a specific pathogenic

Use of abrupt strain path change for determining subsequent yield surface

DEFF Research Database (Denmark)

Kuwabara, T.; Kuroda, M.; Tvergaard, Viggo

2000-01-01

. In a biaxial tensile testing apparatus, a cruciform specimen is used, with the strains measured by a biaxial-strain gauge. Then, with the hydraulic pressure of two sets of opposing hydraulic cylinders servo-controlled independently, the testing apparatus can be used to prescribe an abrupt change of the strain...

Electrocardiogram of Clinically Healthy Mithun (Bos frontalis): Variation among Strains

Science.gov (United States)

Sanyal, Sagar; Das, Pradip Kumar; Ghosh, Probal Ranjan; Das, Kinsuk; Vupru, Kezha V.; Rajkhowa, Chandan; Mondal, Mohan

2010-01-01

A study was conducted to establish the normal electrocardiogram in four different genetic strains of mithun (Bos frontalis). Electrocardiography, cardiac electrical axis, heart rate, rectal temperature and respiration rate were recorded in a total of 32 adult male mithun of four strains (n = 8 each). It was found that the respiration and heart rates were higher (P electrocardiogram of mithun revealed that the amplitude and duration of P wave, QRS complex and T wave were different among four different genetic strains of mithun and the electrical axis of QRS complex for Nagamese and Mizoram mithuns are dissimilar to bovine species. PMID:20886013

Prognostic value of strain and strain rate in the prediction of postoperative atrial fibrillation in patients undergoing coronary artery bypass grafting: a systematic literature review

Directory of Open Access Journals (Sweden)

Leila Bigdelu

2016-03-01

Full Text Available Introduction: Atrial fibrillation (AF is a common dysrhythmia postoperatively after coronary artery bypass grafting (CABG. Myocardial strain and strain-rate imaging is used for the assessment of postoperative atrial fibrillation (POAF as a new echocardiographic method. Methods: PubMed and Scopus were searched thoroughly using the following search terms: (strain and strain rate AND (atrial fibrillation OR AF on March 2015 to find English articles in which the strain and strain-rate echocardiographic imaging had been used for the evaluation of AF in patients undergone CABG. Full text of the relevant papers was fully reviewed for data extraction.Result: Of overall 6 articles found in PubMed, 10 records found in Scopus and 4 articles found through reference list search, only 6 papers fully met the inclusion criteria for further assessment and data extraction. The results of strain and strain-rate assessment showed that in total of 542 patients undergoing CABG, POAF occurred in 106 patients. Studies showed that the reduction of left atrial (LA strain rate is correlated with AF. Consistently, the results of present review showed that LA strain and strain-rate in patients who developed AF postoperatively after CABG are significantly reduced, suggesting that strain and strain-rate could be a predictor of POAF.Conclusion: Based on the obtained results, strain and strain-rate is a suitable and accurate echocardiographic technique in the assessment of left atrial function , and it might be helpful to detect the patients who are at high risk of POAF.

Assessment of Low Cycle Fatigue Behavior of Powder Metallurgy Alloy U720

Science.gov (United States)

Gabb, Tomothy P.; Bonacuse, Peter J.; Ghosn, Louis J.; Sweeney, Joseph W.; Chatterjee, Amit; Green, Kenneth A.

2000-01-01

The fatigue lives of modem powder metallurgy disk alloys are influenced by variabilities in alloy microstructure and mechanical properties. These properties can vary as functions of variables the different steps of materials/component processing: powder atomization, consolidation, extrusion, forging, heat treating, and machining. It is important to understand the relationship between the statistical variations in life and these variables, as well as the change in life distribution due to changes in fatigue loading conditions. The objective of this study was to investigate these relationships in a nickel-base disk superalloy, U720, produced using powder metallurgy processing. Multiple strain-controlled fatigue tests were performed at 538 C (1000 F) at limited sets of test conditions. Analyses were performed to: (1) assess variations of microstructure, mechanical properties, and LCF failure initiation sites as functions of disk processing and loading conditions; and (2) compare mean and minimum fatigue life predictions using different approaches for modeling the data from assorted test conditions. Significant variations in life were observed as functions of the disk processing variables evaluated. However, the lives of all specimens could still be combined and modeled together. The failure initiation sites for tests performed at a strain ratio R(sub epsilon) = epsilon(sub min)/epsilon(sub max) of 0 were different from those in tests at a strain ratio of -1. An approach could still be applied to account for the differences in mean and maximum stresses and strains. This allowed the data in tests of various conditions to be combined for more robust statistical estimates of mean and minimum lives.

Irradiation effects in strain aged pressure vessel steel

Energy Technology Data Exchange (ETDEWEB)

Grounes, M; Myers, H P

1962-02-15

Tensile specimens, Charpy-V notch and subsize impact specimens of an aluminium killed carbon manganese steel, have been irradiated at 160 - 190 deg C in the reactor G1. The total neutron dose received was 2.4 x 10{sup 18} n/cm{sup 2} (> 1 MeV). Specimens were prepared from normalized plate and from strain aged material from the same plate. It was found that the changes in brittle ductile transition temperature due to neutron irradiation and those due to strain ageing must be considered additive.

The ability of a cold-adapted Rhodotorula mucilaginosa strain from Tibet to control blue mold in pear fruit.

Science.gov (United States)

Hu, Hao; Yan, Fujie; Wilson, Charles; Shen, Qing; Zheng, Xiaodong

2015-12-01

Cold-adapted yeasts were isolated from soil samples collected in Tibet and evaluated as potential biocontrol agents against blue mold (Penicillium expansum) of pear fruit in cold storage. YC1, an isolate identified as Rhodotorula mucilaginosa, was found to exhibit the greatest biocontrol activity among the different isolates that were screened. A washed cell suspension of YC1 exhibited the best biocontrol activity among three different preparations that were used in the current study. A concentration of 10(8) cells/ml reduced the incidence of decay to 35 %, compared to the control where decay incidence was 100 %. A higher intracellular level of trehalose and a higher proportion of polyunsaturated acids present in YC1, was associated with increased the tolerance of this strain to low temperatures, relative to the other strains that were evaluated. The increased tolerance to low temperature allowed the YC1 strain of yeast to more effectively compete for nutrients and space in wounded pear fruit that had been inoculated with spores of P. expansum and placed in cold storage. The present study demonstrated the ability to select cold-adapted yeasts from cold climates and use them as biocontrol agents of postharvest diseases of fruit placed in cold storage.

Neuromuscular Strain Increases Symptom Intensity in Chronic Fatigue Syndrome.

Directory of Open Access Journals (Sweden)

Peter C Rowe

Full Text Available Chronic fatigue syndrome (CFS is a complex, multisystem disorder that can be disabling. CFS symptoms can be provoked by increased physical or cognitive activity, and by orthostatic stress. In preliminary work, we noted that CFS symptoms also could be provoked by application of longitudinal neural and soft tissue strain to the limbs and spine of affected individuals. In this study we measured the responses to a straight leg raise neuromuscular strain maneuver in individuals with CFS and healthy controls. We randomly assigned 60 individuals with CFS and 20 healthy controls to either a 15 minute period of passive supine straight leg raise (true neuromuscular strain or a sham straight leg raise. The primary outcome measure was the symptom intensity difference between the scores during and 24 hours after the study maneuver compared to baseline. Fatigue, body pain, lightheadedness, concentration difficulties, and headache scores were measured individually on a 0-10 scale, and summed to create a composite symptom score. Compared to individuals with CFS in the sham strain group, those with CFS in the true strain group reported significantly increased body pain (P = 0.04 and concentration difficulties (P = 0.02 as well as increased composite symptom scores (all P = 0.03 during the maneuver. After 24 hours, the symptom intensity differences were significantly greater for the CFS true strain group for the individual symptom of lightheadedness (P = 0.001 and for the composite symptom score (P = 0.005. During and 24 hours after the exposure to the true strain maneuver, those with CFS had significantly higher individual and composite symptom intensity changes compared to the healthy controls. We conclude that a longitudinal strain applied to the nerves and soft tissues of the lower limb is capable of increasing symptom intensity in individuals with CFS for up to 24 hours. These findings support our preliminary observations that increased mechanical

Driver electronics design and control for a total artificial heart linear motor.

Science.gov (United States)

Unthan, Kristin; Cuenca-Navalon, Elena; Pelletier, Benedikt; Finocchiaro, Thomas; Steinseifer, Ulrich

2018-01-27

For any implantable device size and efficiency are critical properties. Thus, a linear motor for a Total Artificial Heart was optimized with focus on driver electronics and control strategies. Hardware requirements were defined from power supply and motor setup. Four full bridges were chosen for the power electronics. Shunt resistors were set up for current measurement. Unipolar and bipolar switching for power electronics control were compared regarding current ripple and power losses. Here, unipolar switching showed smaller current ripple and required less power to create the necessary motor forces. Based on calculations for minimal power losses Lorentz force was distributed to the actor's four coils. The distribution was determined as ratio of effective magnetic flux through each coil, which was captured by a force test rig. Static and dynamic measurements under physiological conditions analyzed interaction of control and hardware and all efficiencies were over 89%. In conclusion, the designed electronics, optimized control strategy and applied current distribution create the required motor force and perform optimal under physiological conditions. The developed driver electronics and control offer optimized size and efficiency for any implantable or portable device with multiple independent motor coils. Graphical Abstract ᅟ.

Large head metal-on-metal cementless total hip arthroplasty versus 28mm metal-on-polyethylene cementless total hip arthroplasty: design of a randomized controlled trial

Directory of Open Access Journals (Sweden)

van Raaij Jos JAM

2008-10-01

Full Text Available Abstract Background Osteoarthritis of the hip is successfully treated by total hip arthroplasty with metal-on-polyethylene articulation. Polyethylene wear debris can however lead to osteolysis, aseptic loosening and failure of the implant. Large head metal-on-metal total hip arthroplasty may overcome polyethylene wear induced prosthetic failure, but can increase systemic cobalt and chromium ion concentrations. The objective of this study is to compare two cementless total hip arthroplasties: a conventional 28 mm metal-on-polyethylene articulation and a large head metal-on-metal articulation. We hypothesize that the latter arthroplasties show less bone density loss and higher serum metal ion concentrations. We expect equal functional scores, greater range of motion, fewer dislocations, fewer periprosthetic radiolucencies and increased prosthetic survival with the metal-on-metal articulation. Methods A randomized controlled trial will be conducted. Patients to be included suffer from non-inflammatory degenerative joint disease of the hip, are aged between 18 and 80 and are admitted for primary cementless unilateral total hip arthroplasty. Patients in the metal-on-metal group will receive a cementless titanium alloy acetabular component with a cobalt-chromium liner and a cobalt-chromium femoral head varying from 38 to 60 mm. Patients in the metal-on-polyethylene group will receive a cementless titanium alloy acetabular component with a polyethylene liner and a 28 mm cobalt-chromium femoral head. We will assess acetabular bone mineral density by dual energy x-ray absorptiometry (DEXA, serum ion concentrations of cobalt, chromium and titanium, self reported functional status (Oxford hip score, physician reported functional status and range of motion (Harris hip score, number of dislocations and prosthetic survival. Measurements will take place preoperatively, perioperatively, and postoperatively (6 weeks, 1 year, 5 years and 10 years. Discussion