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Sample records for haz softening behavior

  1. Evaluation of HAZ liquation cracking susceptibility and HAZ softening behavior in modified 800H

    Energy Technology Data Exchange (ETDEWEB)

    Lundin, C.D.; Qiao, C.Y.P. (Tennessee Univ., Knoxville, TN (United States). Dept. of Materials Science and Engineering)

    1992-11-20

    A modified 800H alloy, developed at Oak Ridge National Laboratory (ORNL), is one of the candidate materials designed for high temperature applications. Extensive mechanical and corrosion investigations have been completed and it has been proven that modified 800 has excellent high temperature mechanical and metallurgical behavior. Weldability studies of modified 800H are being carried out at the University of Tennessee, Knoxville. A series of modified 800H alloys and two similar commercial high temperature materials (310Ta and HR3C) were used to conduct this investigation. A preliminary weldability evaluation has been accomplished and the major part of the results (HAZ liquation cracking resistance and HAZ softening behavior in modified 800H) is addressed in this report. The basic conclusion of this investigation is that modified 800H material possesses good resistance to HAZ liquation cracking especially with a grain size control (thermo-mechanical treatment). The information from this study is important to the further modification of the material in order to extend its applications.

  2. Effects of Nitrogen Content on the HAZ Softening of Ti-Containing High Strength Steels Manufactured by Accelerated Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Kook-soo; Jung, Ho-shin; Park, Chan [Pukyong National University, Busan (Korea, Republic of)

    2017-03-15

    The effects of nitrogen content on the HAZ softening of Ti-containing high strength steels manufactured by accelerating cooling were investigated and interpreted in terms of the microstructures in the softening zone. Regardless of their content, all of the steels investigated showed a softened zone 9-10 mm wide. The minimum hardness in the zone, however, was different, with lower hardness in the higher nitrogen content steel. Microstructural observations of the steel showed that the amount of soft ferrite was increased in the zone with an increase of nitrogen content of the steel, suggesting that microstructural evolution in the HAZ is influenced by the nitrogen content. Measurements of TiN particles showed that the degree of particles coarsening in the HAZ was lower in the higher nitrogen content steel. Therefore, it is believed that finer TiN particles in the HAZ inhibit austenite grain growth more effectively, and lead to an accelerated ferrite transformation in higher nitrogen content steel, resulting in a higher amount of soft ferrite microstructure in the softened zone.

  3. Failure Behaviors Depending on the Notch Location of the Impact Test Specimens on the HAZ

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Yun Chan; Kim, Dong Wook; Lee, Young Suk [Chungang Univ., Seoul (Korea, Republic of); Hong, Jae Keun; Park, Ji Hong [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2007-07-01

    Numerical studies were performed to examine the effects of notch location of impact specimens on the failure behavior of HAZ (Heat Affected Zone) when Charpy V-notch impact test were made at a low temperature (1 .deg. C). Carbon steel plate (SA-516 Gr. 70) with thickness of 25mm for pressure vessel was welded by SMAW (Shielded Metal-Arc Welding) and specimens were fabricated from the welded plate. Charpy tests were then performed with specimens having different notch positions of specimens varying from the fusion line through HAZ to base metal. A series of finite element analysis which simulates the Charpy test and crack propagation initiating at the tip of V-notch was carried out as well. The finite element analysis takes into account the irregular fusion line and non-homogenous material properties due to the notch location of the specimen in HAZ. Results reveals that the energies absorbed during impact test depend significantly on the notch location and direction of specimen. Finite element analysis also demonstrates that the notch location of specimens, to a great extent, influences the reliability and consistency of the test.

  4. Investigation on fracture behavior of the welded joint HAZ of ultra-fine grain steel SS400

    Institute of Scientific and Technical Information of China (English)

    朱政强; 陈立功; 荆洪阳; 葛景国; 倪纯珍; 饶德林

    2003-01-01

    The critical crack dimensions of both base-metal specimen and HAZ specimen are measured via wide-plate tensile tests. Based on the "fitness for purpose" principle, the fracture behavior of the ultra-fine grain steel SS400 welded joint HAZ is assessed. The test results indicate that overmatching is benefit for the whole capability's improvement of ultra-fine grain steel SS400. The test results are confirmed by using finite element method (FEM).

  5. Fatigue crack growth behavior of the simulated HAZ of 800 MPa grade high-performance steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sanghoon [Division of Materials Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kang, Donghwan; Kim, Tae-Won [School of Mechanical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Lee, Jongkwan [Research Institute of Industrial Science and Technology, 75-9, Youngcheon, Dongtan, Hwaseong, Gyeonggi-do 445-813 (Korea, Republic of); Lee, Changhee, E-mail: chlee@hanyang.ac.kr [Division of Materials Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)

    2011-03-15

    Research highlights: {yields} Fatigue crack resistances of HSB800 base steel and HAZs: Base steel > FGHAZ > CGHAZ > ICCGHAZ. {yields} In the case of ICCGHAZ, fatigue cracks are rapidly initiated and propagated through massive M-A constituents. {yields} Fatigue crack growth rate of CGHAZ was faster than that of FGHAZ, mainly due to the coarsened prior austenite grain and martensite packet. - Abstract: The present study focuses on the fatigue properties in the weld heat-affected zone (HAZ) of 800 MPa grade high-performance steel, which is commonly used in bridges and buildings. Single- and multi-pass HAZs were simulated by the Gleeble system. Fatigue properties were estimated using a crack propagation test under a 0.3 stress ratio and 0.1 load frequencies. The microstructures and fracture surfaces were analyzed by optical microscopy, scanning electron microscopy, and transmission electron microscopy. The results of the crack propagation test showed that the fatigue crack growth rate of coarse-grained HAZ (CGHAZ) was faster than fine-grained HAZ (FGHAZ), although both regions have identical fully martensite microstructures, because FGHAZ has smaller prior austenite grain and martensite packet sizes, which can act as effective barriers to crack propagation. The fatigue crack growth rate of intercritically reheated CGHAZ (ICCGHAZ) was the fastest among local zones in the HAZ, due to rapid crack initiation and propagation via the massive martensite-austenite (M-A) constituent.

  6. Viscosity and Softening Behavior of Alkali Zinc Sulfophosphate Glasses

    DEFF Research Database (Denmark)

    Da, Ning; Krolikowski, Sebastian; Nielsen, Karsten Hansgaard;

    2010-01-01

    We report on the softening properties and viscosity of glasses from the system ZnO-Na2O-SO3-P2O5 for low-temperature sealing applications. Up to a ratio of network-forming ions PO(4)3-:SO(4)2- of about 2:1, a gradual substitution of P2O5 by SO3 results in decreasing glass transition and softening...

  7. Optimization of hardening/softening behavior of plane frame structures using nonlinear normal modes

    DEFF Research Database (Denmark)

    Dou, Suguang; Jensen, Jakob Søndergaard

    2016-01-01

    /softening behavior of nonlinear mechanical systems. The iterative optimization procedure consists of calculation of nonlinear normal modes, solving an adjoint equation system for sensitivity analysis and an update of design variables using a mathematical programming tool. We demonstrate the method with examples......Devices that exploit essential nonlinear behavior such as hardening/softening and inter-modal coupling effects are increasingly used in engineering and fundamental studies. Based on nonlinear normal modes, we present a gradient-based structural optimization method for tailoring the hardening...

  8. Microstructure and Precipitation Behavior in HAZ of V and Ti Microalioyed Steel

    Institute of Scientific and Technical Information of China (English)

    FANG Fang; YONG Qi-long; YANG Cai-fu; SU Hang

    2009-01-01

    Three steels containing 0.05%C-0.1%V-0.01%N (steel V-LN),0.05%C-0.1%V-0.02%N (steel V-HN),and 0.05%C-0.1%V-0.02%N-0.01%Ti (steel V-HN-Ti),which were all essentially vanadium microalloyed steels,were subjected to simulating the microstructure of a coarse grained heat affected zone (CGHAZ).The process involved reheating to 1 350 ℃,rapid cooling to room temperature,and varying the welding heat input from 15 kJ/cm to 54 kJ/cm,including four cooling rates of t8/5 equal to 7.5 s,20 s,40 s,100 s,and the relationship of heat input to t8/5 was calculated by Quiksim software.The microstructure and precipitation of vanadium and titanium carbon nitrides are studied.The results indicate that the microstructure consists of granular bainite and some side plate ferrite in the grain boundary when the steels are produced with the highest heat input.As the heat input decreased,numerous polygonal ferrites and grain boundary ferrites appeared,and the size apparently increased.When the steel contained high nitrogen,it was considerably easier to form martensite-austenite island,which was even worse for the toughness and other properties of the steel.For the limitation of cooling time,vanadium carbon nitrides could not precipitate sufficiently,but as titanium was added,the unmelted or precipitated TiN on cooling absorbed some fraction of nitrogen in the matrix and made more precipitate positions for the round V(C,N),and thus several useful round particles could be seen in titanium-contained steel,and most of them were around TiN.By this experiment,we can conclude that with the help of titanium,nitrogen-enhanced steel had a better prior austenite grain size,was considerably easier to precipitate,reduced free nitrogen in the matrix effectively,and provided a very effective mechanism for restriction grain growth in the HAZ.

  9. BASIC STUDY ON TENSION SOFTENING AND CYCLIC DEFORMATION BEHAVIOR OF SOLIDIFIED BODY FOR THE COHESIVE SOIL

    Science.gov (United States)

    Urano, Kazuhiko; Adachi, Yuji; Mihara, Masaya; Yamada, Atsuo; Kawamura, Makoto

    So far, authors have proposed a method to improve earthquake resistance of pile foundations by partially solidifying an underground part of the pile foundations, and the effect of reinforcement has been confirmed by shaking table tests and the lateral loading tests of a full scale model. Though the solidified body is usually designed as an elastic body, it is possible to design the body considering the damage by the tensile stress when a seismic ground motion is assumed to be level 2. Therefore, material tests of the solidified body for the cohesive soil were executed, and the characteristics of the tension softening and the cyclic deformation behavior of the solidified bod y were clarified. Moreover, loading tests that used wall models of the solidified body were executed, and the effects of the shape on the tension softening and the cyclic deformation behavior of the solidified body were clarified. In addition, a numerical simulation by elastoplastic FEM analysis that considers the damage of the solidified body was executed, and the tension softening and the cyclic deformation behavior of the solidified body were reproduced.

  10. Determination of the strain rate dependent thermal softening behavior of thermoplastic materials for crash simulations

    Science.gov (United States)

    Hopmann, Christian; Klein, Jan; Schöngart, Maximilian

    2016-03-01

    Thermoplastic materials are increasingly used as a light weight replacement for metal, especially in automotive applications. Typical examples are frontends and bumpers. The loads on these structures are very often impulsive, for example in a crash situation. A high rate of loading causes a high strain rate in the material which has a major impact on the mechanical behavior of thermoplastic materials. The stiffness as well as the rigidity of polymers increases to higher strain rates. The increase of the mechanical properties is superimposed at higher rates of loading by another effect which works reducing on stiffness and rigidity, the increase of temperature caused by plastic deformation. The mechanical behavior of thermoplastic materials is influenced by temperature opposing to strain rate. The stiffness and rigidity are decreased to higher values of temperature. The effect of thermal softening on thermoplastic materials is investigated at IKV. For this purpose high-speed tensile tests are performed on a blend, consisting of Polybutylenterephthalate (PBT) and Polycarbonate (PC). In preliminary investigations the effects of strain rate on the thermomechanical behavior of thermoplastic materials was studied by different authors. Tensile impact as well as split Hopkinson pressure bar (SHPB) tests were conducted in combination with high-speed temperature measurement, though, the authors struggled especially with temperature measurement. This paper presents an approach which uses high-speed strain measurement to transpire the link between strain, strain rate and thermal softening as well as the interdependency between strain hardening and thermal softening. The results show a superimposition of strain hardening and thermal softening, which is consistent to preliminary investigations. The advantage of the presented research is that the results can be used to calibrate damage and material models to perform mechanical simulations using Finite Element Analysis.

  11. Haz-Map

    Data.gov (United States)

    U.S. Department of Health & Human Services — Haz-Map is an occupational health database designed for health and safety professionals and for consumers seeking information about the adverse effects of workplace...

  12. Hysteretic Behavior of Ligaments and Tendons: Microstructural Analysis of Damage, Softening and Non-Recoverable Stra

    Science.gov (United States)

    Ciarletta, P.; Amar, M. Ben

    A microstructural analysis of the hysteretic behavior of ligaments and tendons is proposed from the interaction of their extra-cellular matrix (ECM) components. The tensile response of the tissues during cyclic loading is modeled through a viscoelastic strain energy function. A transition-state theory is used to define the cooperative behavior of the temporary fibrillar network. The viscoelastic model incorporates four internal variables, describing the kinetics of two kinds of adaptive junctions in the ECM microstructure. Two softening variables ξ m , ξ f account for the number density of active matter that is actively connected in the rearranging network of temporary junctions. Conversely, two damage variables η m , η f provide the number density of matter that have been damaged and cannot be rearranged. A dissipation energy functionΦ(t) is linked to the internal variables by thermodynamically consistent evolution equations, describing the irreversible energy dissipation in the tensile cycle of loading and unloading. The model demonstrates the fundamental role of the ECM interactions in determining the time-dependent storage and release of elastic strain energy in ligaments and tendons.

  13. The Myth of Softening behavior of the Cohesive Zone Model Exact derivation of yield drop behavior of wood

    NARCIS (Netherlands)

    Van der Put, T.A.C.M.

    2015-01-01

    It is shown that the postulate of strain softening of the fracture stress is based on the error to regard the nominal stress to be the actual, ultimate stress, at the actual area of the fracture plan. Strain sof-tening called yield drop is elastic unloading of the actual elastic stress at the

  14. Oxidation behavior of base metal, weld metal and HAZ regions of SMAW weldment in ASTM SA210 GrA1 steel

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Ravindra [Metallurgical and Materials Engineering Department, Indian Institute of Technology Roorkee, Roorkee 247667 (India)], E-mail: ravirs_2002@rediffmail.com; Tewari, V.K.; Prakash, Satya [Metallurgical and Materials Engineering Department, Indian Institute of Technology Roorkee, Roorkee 247667 (India)

    2009-06-24

    Shielded metal arc welding (SMAW) was used to weld together ASTM SA210 GrA1 steel. The oxidation studies were conducted on different regions of shielded metal arc weldment i.e., base metal, weld metal and heat affected zone (HAZ) specimens after exposure to air at 900 deg. C under cyclic conditions. The thermo-gravimetric technique was used to establish kinetics of oxidation. X-ray diffraction (XRD) and scanning electron microscopy/energy-dispersive analysis (SEM/EDAX) techniques were used to analyze the oxidation products. Base metal showed more weight gain than that of weld metal and HAZ. The HAZ specimen showed the least weight gain due to the formation of densely inner oxide scale.

  15. Softening Behavior of Hardness and Surface Fatigue of Rolling-Sliding Contact in the Case of Developed Alloy Steels

    Science.gov (United States)

    Redda, Daniel Tilahun; Nakanishi, Tsutomu; Deng, Gang

    To get high performance, downsizing and weight saving of the power transmission systems, the improvement of machine elements has been required. In this study, case-carburized gear materials for a high load-carrying capacity were developed. Low-alloyed steels with 1%Cr-0.2%Mo, 1%Cr-0.2%Mo-1%Si and 1%Cr-0.2%Mo-2%Ni (Cr-Mo steel, Cr-Mo-Si steel and Cr-Mo-Ni steel) were melted in a hypoxia vacuum. Test rollers were made of the developed steels, and they were carburized (Type A and Type B), hardened and tempered. Heating retention tests were carried out to investigate the softening behavior of hardness at high heating temperatures in the case of the developed steels. Roller tests were conducted under the rolling-sliding contact and high-load conditions to study the surface fatigue of the developed steels. From the obtained test results, it was found that the softening behavior of surface hardness at high temperatures in the cases of Cr-Mo-Si steel (Type A) and Cr-Mo-Ni steel (Type B) is lower than that in the cases of Cr-Mo steel (Type A) and Cr-Mo steel (Type B). In the cases of Cr-Mo-Si steel (A) and Cr-Mo-Ni steel (B), micro- and small-pitting area ratios are smaller and large-pitting life is longer than those in the cases of Cr-Mo steel(A) and Cr-Mo steel(B) under the same carburizing treatment method and high-load conditions. Furthermore, the relationship between the softening behavior of surface hardness on the heating pattern and the surface fatigue on the rolling-sliding contact of the developed alloy steels was clarified.

  16. Mesoscopic analysis of the utilization of hardening model for a description of softening behavior based on disturbed state concept theory

    Institute of Scientific and Technical Information of China (English)

    Jian-ye ZHENG; An-li WU

    2008-01-01

    Mesoscopic characteristics of a clayey soil specimen subjected to macroscoptc loading are examined usmg a medical-use computerized tomography(CT)instrument.Disturbed state concept(DSC)theory is based on the utilization of the hardening model.DSC indirectly describes rnaterial behavior by claiming that the actual response of the material is expressed in terms of the relative intact(RI)response and the fully adjusted(FA) response.The occurrence of mesoscopic structural changes of material has similarities with the occurrence of a macroscopic response of the material under loadings.In general,the relative changing value of a softening material iS three to five times more than that of a hardening material.Whether special zones exist or not in a specimen cross section does not affect the following conclusion:hardening material and softening material show mechanical dififerences with CT statistical indices values prominently changing,and the change is related to the superposmg of a disturbance factor.A new disturbance factor evolution function is proposed.Thus,mesoscopic statistical indices are introduced to describe macroscopic behavior through the new evolution function.An application of the new evolution function proves the effectiveness of the amalgamation of a macroscopic and a mesoscopic experimental phenomenon measurement methods.

  17. A Critical Assessment of Cyclic Softening and Hardening Behavior in a Near- α Titanium Alloy During Thermomechanical Fatigue

    Science.gov (United States)

    Prasad, Kartik; Sarkar, Rajdeep; Rao, K. Bhanu Sankara; Sundararaman, M.

    2016-10-01

    Thermomechanical fatigue behavior of Ti-alloy Timetal 834 has been studied at two temperature intervals viz. 573 K to 723 K (300 °C to 450 °C) and 723 K to 873 K (450 °C to 600 °C) under mechanical strain-controlled cycling. Among the temperatures studied, the alloy exhibited initial cyclic softening followed by cyclic hardening at 723 K (450 °C) in the temperature interval of 573 K to 723 K (300 °C to 450 °C). However, continuous cyclic hardening was observed at 723 K (450 °C) in 723 K to 873 K (450 °C to 600 °C). At 573 K (300 °C) and 873 K (600 °C), cyclic softening was observed in the cyclic stress response curves in both the temperature intervals. The dislocation substructure was observed to be planar in both the modes of TMF loading. Based on TEM microstructures and few unconventional fatigue tests, the observed cyclic hardening is attributed to dynamic strain aging. The reduced fatigue life at 723 K to 873 K (450 °C to 600 °C) under OP-TMF loading was attributed to the combined effect of cyclic hardening (leading to early strain localization and crack initiation), oxidation, and development of tensile mean stresses.

  18. Alloy softening in binary iron solid solutions

    Science.gov (United States)

    Stephens, J. R.; Witzke, W. R.

    1976-01-01

    An investigation was conducted to determine softening and hardening behavior in 19 binary iron-alloy systems. Microhardness tests were conducted at four temperatures in the range 77 to 411 K. Alloy softening was exhibited by 17 of the 19 alloy systems. Alloy softening observed in 15 of the alloy systems was attributed to an intrinsic mechanism, believed to be lowering of the Peierls (lattice friction) stress. Softening and hardening rates could be correlated with the atomic radius ratio of solute to iron. Softening observed in two other systems was attributed to an extrinsic mechanism, believed to be associated with scavenging of interstitial impurities.

  19. The Influence of Processing Conditions on Microchemistry and the Softening Behavior of Cold Rolled Al-Mn-Fe-Si Alloys

    Directory of Open Access Journals (Sweden)

    Ning Wang

    2016-03-01

    Full Text Available Using different homogenization treatments, different initial microchemistry conditions in terms of solid solution levels of Mn, and number densities and sizes of constituents and dispersoids were achieved in an Al-Mn-Fe-Si model alloy. For each homogenized condition, the microchemistry and microstructure, which further change both during deformation and subsequent annealing, were quantitatively characterized. The influence of the different microchemistries, with special focus on different particle structures (constituents and dispersoids, on the softening behavior during annealing after cold rolling and the final grain structure has been systematically studied. Time-Temperature-Transformation diagrams with respect to precipitation and recrystallization as a basis for analysis of the degree of concurrent precipitation during back-annealing have been established. Densely distributed fine pre-existing dispersoids and/or conditions of significant concurrent precipitation strongly slows down recrystallization kinetics and lead to a grain structure of coarse and strongly elongated grains. At the lowest annealing temperatures, recrystallization may even be completely suppressed. In conditions of low number density and coarse pre-existing dispersoids, and limited additional concurrent precipitation, recrystallization generally results in an even, fine and equi-axed grain structure. Rough calculations of recrystallized grain size, assuming particle stimulated nucleation as the main nucleation mechanism, compare well with experimentally measured grain sizes.

  20. Finite element implementation of the Hoek-Brown material model with general strain softening behavior

    DEFF Research Database (Denmark)

    Sørensen, Emil Smed; Clausen, Johan Christian; Damkilde, Lars

    2015-01-01

    A numerical implementation of the Hoek–Brown criterion is presented, which is capable of modeling different post-failure behaviors observed in jointed rock mass. This is done by making the material parameters a function of the accumulated plastic strain. The implementation is for use in finite...... element calculations, and is based on the return mapping framework. The updated stress state together with the consistent constitutive matrix is found in principal stress space based on the principles of boundary planes. The implementation is verified through the simulation of a tunnel excavation...

  1. Fatigue crack growth prediction in 2xxx AA with friction stir weld HAZ properties

    Directory of Open Access Journals (Sweden)

    A. Tzamtzis

    2016-02-01

    Full Text Available An analytical model is developed to predict fatigue crack propagation rate under mode I loading in 2024 aluminum alloy with FSW HAZ material characteristics. Simulation of the HAZ local properties in parent 2024 AA was performed with overaging using specific heat treatment conditions. The model considers local cyclic hardening behavior in the HAZ to analyze crack growth. For the evaluation of the model, the analytical results have been compared with experimental fatigue crack growth on overaged 2024 alloy simulating material behavior at different positions within the HAZ. The analytical results showed that cyclic hardening at the crack tip can be used successfully with the model to predict FCG in a material at overaged condition associated with a location in the FSW HAZ.

  2. Stress Softening Behavior in the Mucosa-Submucosa and Muscle Layers in Normal and Diabetic Rat Esophagus

    DEFF Research Database (Denmark)

    Jiang, Hongbo; Liao, Donghua; Zhao, Jingbo

    2015-01-01

    Background & aims: Stress softening is a feature of mechanical preconditioning in soft tissue. Previously, we demonstrated that esophageal stress softening is reversible by muscle activation with KCl. Since the esophagus consists of muscle and mucosa-submucosa layers, the aim was to study......M KCl was added for maximum contraction for 3min. KCl was washed out to permit relaxation and contractions were eliminated by immersion into Ca2+-free solution. After 1h rest, the tubes were exposed to five repeated ramp distensions conformed to the aforesaid two series. Stress-strain curves were used...... losses due to stress softening were recovered by KCl-induced contraction. Such losses could not be recovered by KCl in the diabetic esophageal muscle layer. The normal esophageal mucosa-submucosa layer obtained extra energy gain by KCl activation whereas the diabetic mucosa-submucosa layer became softer...

  3. Reuse of experience in HazOp

    OpenAIRE

    Abrahamsen, Kristin Marheim; Knudsen, Andreas

    2004-01-01

    This report presents a study of the effect of reusing experience in the Hazards and Operability Analysis method (HazOp method) with regards to how the effectiveness of the method is affected. The study was conducted by first creating a software tool for experience reuse in HazOp, then testing that tool in a student experiment in which the participants used the tool when conducting a HazOp.During the experiment it was found that students using the tool found 21% more hazards in the system unde...

  4. Effect of welding heat input on HAZ character in ultra-fine grain steel welding

    Institute of Scientific and Technical Information of China (English)

    张富巨; 许卫刚; 王玉涛; 王燕; 张学刚; 廖永平

    2003-01-01

    In this essay, we studied how heat input affected the microstructure, hardness, grain size and heat-affected zone(HAZ) dimension of WCX355 ultra-fine grain steel which was welded respectively by the ultra narrow-gap welding (UNGW) process and the overlaying process with CO2 as protective atmosphere and laser welding process. The experimental results show when the heat input changed from 1.65kJ/cm to 5.93kJ/cm, the width of its HAZ ranged from 0.6mm to 2.1mm.The average grain size grew up from 2~5μm of base metal to 20~70μm and found no obvious soften phenomenon in overheated zone. The width of normalized zone was generally wide as 2/3 as that of the whole HAZ, and the grain size in this zone is smaller than that in base metal. Under the circumstance of equal heat input, the HAZ width of UNGW is narrower than that of the laser welding.

  5. EFFECTS OF THERMAL CYCLE ON MECHANICAL PROPERTIES AND FRACTOGRAPHY IN HAZ OF HQ130 STEEL

    Institute of Scientific and Technical Information of China (English)

    B. Liu; J.X. Qu; W.J. Sun

    2004-01-01

    The effect of different peak temperature (Tp) and cooling time (ts/5) on hardness,impact toughness and fracture morphology in the heat-affected zone (HAZ) of HQ130steel was studied by using welding thermo-simulation test. Experimental results show that the impact toughness and hardness decrease with the decrease of Tp or increase of t8/5 under the condition of a single thermal cycle. There is a brittle zone in the vicinity of Tp=800℃, where the impact toughness is considerably low. There is softened zone in vicinity of Tp=700℃, Where the hardness decreases but the toughness increases. In the practical application of multi-layer and multi-pass welding, the welding heat input should be strictly limited (t8/5≤20s) so as to reduce the softness and brittleness in the HAZ of HQ130 steel.

  6. Viscosity anomaly in core-softened liquids

    OpenAIRE

    Fomin, Yu. D.; Ryzhov, V. N.

    2013-01-01

    The present article presents a molecular dynamics study of several anomalies of core-softened systems. It is well known that many core-softened liquids demonstrate diffusion anomaly. Usual intuition relates the diffusion coefficient to shear viscosity via Stockes-Einstein relation. However, it can break down at low temperature. In this respect it is important to see if viscosity also demonstrates anomalous behavior.

  7. EFFECT OF MICROSTRUCTURE ON THE HARDENING AND SOFTENING BEHAVIORS OF POLYCRYSTALLINE SHAPE MEMORY ALLOYS PART I: MICROMECHANICS CONSTITUTIVE MODELING

    Institute of Scientific and Technical Information of China (English)

    Song Guquan; Sun Qingping; Hwang Kehchih

    2000-01-01

    The effects of microstructure and its evolution on the macroscopic superelastic stress-strain response of polycrystalline Shape Memory Alloy (SMA) are studied by a microstructure-based constitutive model developed in this paper. The model is established on the following basis: (1) the transformation conditions of the unconstrained single crystal SMA microdomaln (to be distinguished from the bulk single crystal), which serve as the local criterion for the derivation of overall transformation yield conditions of the polycrystal; (2) the micro-to macro-transition scheme by which the connection between the polycrystal aggregates and the single crystal microdomain is established and the macroscopic transformation conditions of the polycrystal SMA are derived;(3) the quantitative incorporation of three microstructure factors ( i.e., nucleation, growth and orientation distribution of martensite) into the modeling. These microstructural factors are intrinsic of specific polycrystal SMA systems and the role of each factor in the macroscopic constitutive response is quantitatively modeled. It is demonstrated that the interplay of these factors will result in different macroscopic transformation kinematics and kinetics which are responsible for the observed macroscopic stress-strain hardening or softening response, the latter will lead to the localization and propagation of transformation bands in TiNi SMA.

  8. The softening effect of heat-treated strengthened Al-Zn-Mg alloy in welding process

    Science.gov (United States)

    Zhang, Xiaohong; Chen, Jingqing; Zhang, Kang; Chen, Hui

    2017-07-01

    Weld joint softening occurs during the welding process of heat-treatable aluminum alloys and strongly influences the mechanical properties. In this work, the softening of heat-treated Al-Zn-Mg alloy was studied in the multipass welding process. By Gleeble-3500 thermal-mechanical simulator, the heat treatment and tensile test with welding thermal cycles were carried out to simulate the microstructure evolution and mechanical softening during multipass welding. After that, the softening mechanism of the HAZ was analyzed by microstructure analysis. The results indicate that the heat-treated Al-Zn-Mg alloy exhibited obvious softening after several thermal cycles with peak temperature higher than 200∘C, and this phenomenon is worse with increasing peak temperature. Based on the microstructure analysis, it was found that the reinforcement phase changes according to the applied thermal cycles, which strongly affects the strength of Al-Zn-Mg alloys.

  9. Numerical simulation of friction stir welding (FSW): Prediction of the heat affect zone using a softening model

    Science.gov (United States)

    Paulo, R. M. F.; Carlone, P.; Valente, R. A. F.; Teixeira-Dias, F.; Palazzo, G. S.

    2016-10-01

    In this work a numerical model is proposed to simulate Friction Stir Welding (FSW) process in AA2024-T3 plates. This model included a softening model that account for the temperature history and the hardness distribution on a welded plate can thus be predicted. The validation of the model was performed using experimental measurements of the hardness in the plate cross-section. There is an acceptable prediction of the material softening in the Heat Affected Zone (HAZ) using the adopted model.

  10. Hazardous chemical tracking system (HAZ-TRAC)

    Energy Technology Data Exchange (ETDEWEB)

    Bramlette, J D; Ewart, S M; Jones, C E

    1990-07-01

    Westinghouse Idaho Nuclear Company, Inc. (WINCO) developed and implemented a computerized hazardous chemical tracking system, referred to as Haz-Trac, for use at the Idaho Chemical Processing Plant (ICPP). Haz-Trac is designed to provide a means to improve the accuracy and reliability of chemical information, which enhances the overall quality and safety of ICPP operations. The system tracks all chemicals and chemical components from the time they enter the ICPP until the chemical changes form, is used, or becomes a waste. The system runs on a Hewlett-Packard (HP) 3000 Series 70 computer. The system is written in COBOL and uses VIEW/3000, TurboIMAGE/DBMS 3000, OMNIDEX, and SPEEDWARE. The HP 3000 may be accessed throughout the ICPP, and from remote locations, using data communication lines. Haz-Trac went into production in October, 1989. Currently, over 1910 chemicals and chemical components are tracked on the system. More than 2500 personnel hours were saved during the first six months of operation. Cost savings have been realized by reducing the time needed to collect and compile reporting information, identifying and disposing of unneeded chemicals, and eliminating duplicate inventories. Haz-Trac maintains information required by the Superfund Amendment Reauthorization Act (SARA), the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) and the Occupational Safety and Health Administration (OSHA).

  11. Effect of MgO content in sinter on the softening-melting behavior of mixed burden made from chromium-bearing vanadium-titanium magnetite

    Institute of Scientific and Technical Information of China (English)

    Xiang-xin Xue

    2016-01-01

    The effect of sinter with different MgO contents on the softening–melting behavior of mixed burden made from chro-mium-bearing vanadium–titanium magnetite was investigated. The results show that with increasing MgO content in the sinter, the softening interval and melting interval increased and the location of the cohesive zone shifted downward slightly and became moderately thicker. The softening–melting characteristic value was less pronounced when the MgO content in the sinter was 2.98wt%–3.40wt%. Increasing MgO content in the sinter reduced the content and recovery of V and Cr in the dripped iron. In addition, greater MgO contents in the sinter resulted in the generation of greater amounts of high-melting-point components, which adversely affected the permeability of the mixed burden. When the softening–melting behavior of the mixed burden and the recovery of valuable elements were taken into account, proper MgO con-tents in the sinter and slag ranged from 2.98wt% to 3.40wt% and from 11.46wt% to 12.72wt%, respectively, for the smelting of burden made from chromium-bearing vanadium–titanium magnetite in a blast furnace.

  12. Mechanical behavior of concrete and related porous materials under partial saturation: The effective stress and the viscous softening due to movement of nanometer-scale pore fluid

    Science.gov (United States)

    Vlahinic, Ivan

    It has been said that porous materials are like music: the gaps are as important as the filled-in bits. In other words, in addition to the solid structure, pore characteristics such as size and morphology play a crucial role in defining the overall physical properties of the porous materials. This work goes a step further and examines the behaviors of some porous media that arise when the pore network is occupied by two fluids, principally air and water, as a result of drying or wetting. Such a state gives rise to fluid capillarity which can generate significant negative fluid pressures. In the first part, a constitutive model for drying of an elastic porous medium is proposed and then extended to derive a novel expression for effective stress in partially saturated media. The model is motivated by the fact that in a system that is saturated by two different fluids, two different pressure inherently act on the surfaces of the pore network. This causes a non-uniform strain field in the solid structure, something that is not explicitly accounted for in the classic formulations of this problem. We use some standard micromechanical homogenization techniques to estimate the extent of the 'non-uniformity' and on this basis, evaluate the validity of the classic Bishop effective stress expression for partially saturated materials. In the second part, we examine a diverse class of porous materials which behave in an unexpected (and even counterintuitive) way under the internal moisture fluctuations. In particular, during wetting and drying alike, the solid viscosity of these materials appears to soften, sometimes by an order of magnitude or more. Under load, this can lead to significantly increased rates of deformations. On account of the recent experimental and theoretical findings on the nature of water flow in nanometer-size hydrophillic spaces, we provide a physical explanation for the viscous softening and propose a constitutive law on this basis. To this end, it also

  13. Microstructure, Tensile Properties and Work Hardening Behavior of GTA-Welded Dual-Phase Steels

    Science.gov (United States)

    Ashrafi, H.; Shamanian, M.; Emadi, R.; Saeidi, N.

    2017-03-01

    In the present study, microstructure, tensile properties and work hardening behavior of a DP700 steel after gas tungsten arc welding were investigated. Formation of bainite in the fusion zone resulted in a hardness increase compared to that for the base metal (BM), whereas tempering of the pre-existing martensite in the subcritical heat-affected zone (HAZ) led to softening. The GTA-welded joint exhibited a continuous yielding behavior and a yield strength close to that for the BM, while its ultimate tensile strength and total elongation were lower than those for the BM owing to the formation of soft zone in the HAZ. A joint efficiency of about 81% was obtained for the GTA-welded joint, and it failed in the softened HAZ. Analysis of work hardening based on the Kocks-Mecking approach showed one stage of hardening behavior corresponding to the stage III for both the DP700 BM and welded sample. It was also revealed that the DP700 BM has larger values of work hardening exponent and magnitude of work hardening compared with the welded sample. Analysis of fractured surfaces showed that the dominant fracture mode for both the DP700 BM and welded joint was ductile.

  14. RESEARCH ON THE WARM FORGING OF ALUMINUM ALLOYS:DEVELOPMENT OF A FORMULA TO DESCRIBE THE SOFTENING BEHAVIOR OF A2011 IN FORGING PROCESS

    Institute of Scientific and Technical Information of China (English)

    X.H. Zhang, K. Osakada; X. Y. Ruan

    2003-01-01

    To understand the forming behaviour of aluminum alloys, the upsetting test of alu-minum alloys at evaluated temperature is conducted. Because in warm forging theflow stress decreases with increasing straining, which is so-called work softening, noappropriate material formulation is available. For the evaluation of flow stress ofaluminum alloys in warm forging processes, in this paper, a formula is derived byanalyzing the stress data measured at various temperatures. It is demonstrated thatthe formula fits the flow stress obtained from experiment.

  15. Softening phenomenon during compression test in nanograined aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ko, S.H.; Jang, J.M.; Lee, W. [Korea Inst. of Industrial Technology, ChonAn (Korea)

    2005-07-01

    Al-Mg and Al-Mg-Cu alloys are known well to reveal superplasticity in tension at high temperatures. In this study, deformation behaviors of those alloys nanograined were investigated under compression test at room temperature. During plastic deformation softening phenomena occurred obviously in nanograined Al-1.5wt%Mg and Al-0.7wt%Mg-1.0wt%Cu alloys while slight strain hardening appeared in nanograined pure Al. These results suggest that the softening strongly depends on composition of alloys. The softening takes place over strain rate range from 10{sup -4} up to 10{sup -1}. (orig.)

  16. Resilience and ductility of Oxy-fuel HAZ cut

    Directory of Open Access Journals (Sweden)

    A. Martín-Meizoso,

    2014-10-01

    Full Text Available Cutting processes affect the material to a deeper or shallower attached-to-the-cut zone. Its microstructure, its hardness and mechanical properties are changed. Also the cutting process introduces surface roughness and residual stresses. In most cases it is recommended to remove this region by grinding, in order to keep a smoother surface, free from the above mentioned effects. This work presents the characterization results of the Heat Affected Zone (HAZ of a steel plate of grade S460M, with a thickness of 25 mm, cut by flame oxyfuel gas cutting. The HAZ microstructure is observed (and the depth of the HAZ measured, the hardness profile and the stress vs. strain curves until fracture are measured by testing micro-tensile samples, instrumented with strain gauges. Micro-Tensile specimens are 200 microns in thickness and were obtained from layers of the HAZ at different distances from the oxy-fuel cut. The obtained stress-strain curves are compared with the hardness measurements and the observed metallography.

  17. Behavior of exposed human lymphocytes to a neutron beam of the Reactor TRIGA Mark III; Comportamiento de linfocitos humanos expuestos a un haz de neutrones del Reactor Triga Mark III

    Energy Technology Data Exchange (ETDEWEB)

    Carbajal R, M. I.; Arceo M, C.; Aguilar H, F.; Guerrero C, C., E-mail: citlali.guerrero@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2012-10-15

    The living beings are permanently exposed to radiations of natural origin: cosmic and geologic, as well as the artificial radiations that come from sources elaborated by the man. The artificial sources have an important use in the medical area. Particularly has been increased the neutrons use due to the effectiveness that they have to damage the cells with regard to other radiation types. The biological indicator of exposition to ionizing radiation more reliable is the chromosomal aberrations study, specifically the dicentrics in human lymphocytes. This test allows, establishing the exposition dose in function of the damage quantity. The dicentrics have a behavior in function of the dose. The calibration curve that describes this behavior is specific for each type of ionizing radiation. In the year 2006 beginning was given to the expositions of human lymphocytes to a neutron beam generated in the reactor TRIGA Mark III of the Instituto Nacional de Investigaciones Nucleares (ININ) in Mexico. Up to 2008 the response dose curve comprised an interval of exposition time of up to 30 minutes. Moreover, the interval between 10 an 20 minutes is included, since was observed that this last is indispensable for the adjustment waited in a lineal model. (Author)

  18. Study of Flow Softening Mechanisms of a Nickel-Based Superalloy With Δ Phase

    Directory of Open Access Journals (Sweden)

    Lin Y.C.

    2016-09-01

    Full Text Available The flow softening behaviors of a nickel-based superalloy with δ phase are investigated by hot compression tests over wide ranges of deformation temperature and strain rate. Electron backscattered diffraction (EBSD, optical microscopy (OM, and scanning electron microscopy (SEM are employed to study the flow softening mechanisms of the studied superalloy. It is found that the flow softening behaviors of the studied superalloy are sensitive to deformation temperature and strain rate. At high strain rate and low deformation temperature, the obvious flow softening behaviors occur. With the increase of deformation temperature or decrease of strain rate, the flow softening degree becomes weaken. At high strain rate (1s−1, the flow softening is mostly induced by the plastic deformation heating and flow localization. However, at low strain rate domains (0.001-0.01s−1, the effects of deformation heating on flow softening are slight. Moreover, the flow softening at low strain rates is mainly induced by the discontinuous dynamic recrystallization and the dissolution of δ phase (Ni3Nb.

  19. On relationship between microfissuring and microstructure in the HAZ of Inconel 718

    Science.gov (United States)

    Thompson, R. G.

    1982-01-01

    Inconel 718, as well as many other metals, is susceptible to intergranular hot cracking in the weld heat-affected-zone (HAZ). These cracks form near the solidus temperature of the metal during the welding process. This problem is of particular concern to NASA/MSFC because the SSME is primarily constructed of welded Inconel 718. The present program studied microfissuring in the weld HAZ of Inconel 718 by simulating HAZ thermal cycles with the Gleeble machine. Previous researchers have studied the instantaneous mechanical properties of the HAZ using the Gleeble. The present study examines the instantaneous microstructure of the HAZ. This approach showed that second phase structures, high in niobium, melt and wet the grain boundaries in the HAZ during welding. It is postulated that the resultant HAZ grain boundaries, enriched in niobium, act as preferred sites for microfissure nucleation as the weld zone cools.

  20. Numerical study of the Notch Location of the Impact Test Specimens on the HAZ of SA516 Steels

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Yun Chan; Kim, Dong Wook; Lee, Young Seog [Chungang Univ., Seoul (Korea, Republic of); Hong, Jae Keun; Park, Ji Hong [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2007-07-01

    Experimental and numerical studies were performed to examine the effects of notch position on the failure behavior and energy absorption when the Charpy V-notch impact test is made at 1 .deg. C. For this purpose, carbon steel plate (SA-516 Gr. 70) with thickness of 25mm usually used for pressure vessel was welded by SMAW (Shielded Metal-Arc Welding) method and specimens were fabricated from the welded plate. The Charpy impact tests were then performed with specimens having different notch positions varying within HAZ. A series of three-dimensional FE analysis which simulates the Charpy test and crack propagation are carried out as well to examine the reproducibility of test results. The FE analysis takes into account the heterogeneous mechanical properties with complex microstructures in HAZ. Results reveal that the absorbed energies during impact test depend significantly on the notch position.

  1. Microstructure and dynamic tensile behavior of DP600 dual phase steel joint by laser welding

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Danyang, E-mail: dongdanyang@mail.neu.edu.cn [College of Science, Northeastern University, No. 11, Lane 3, WenHua Road, HePing District, Shenyang 110819 (China); Liu, Yang, E-mail: liuyang@mail.neu.edu.cn [Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education, Northeastern University, Shenyang 110819 (China); Yang, Yuling, E-mail: yulingyang@mail.neu.edu.cn [College of Science, Northeastern University, No. 11, Lane 3, WenHua Road, HePing District, Shenyang 110819 (China); Li, Jinfeng, E-mail: lijinfengboda@163.com [College of Science, Northeastern University, No. 11, Lane 3, WenHua Road, HePing District, Shenyang 110819 (China); Ma, Min, E-mail: sharon6789@163.com [College of Science, Northeastern University, No. 11, Lane 3, WenHua Road, HePing District, Shenyang 110819 (China); Jiang, Tao, E-mail: tao.jiang906@yahoo.com [College of Science, Northeastern University, No. 11, Lane 3, WenHua Road, HePing District, Shenyang 110819 (China)

    2014-01-31

    Dual phase (DP) steels have been widely used in the automotive industry to reduce vehicle weight and improve car safety. In such applications welding and joining have to be involved, which would lead to a localized change of the microstructure and property, and create potential safety and reliable issues under dynamic loading. The aim of the present study is to examine the rate-dependent mechanical properties, deformation and fracture behavior of DP600 steel and its welded joint (WJ) produced by Nd:YAG laser welding over a wide range of strain rates (0.001–1133 s{sup −1}). Laser welding results in not only significant microhardness increase in the fusion zone (FZ) and inner heat-affected zone (HAZ), but also the formation of a softened zone in the outer HAZ. The yield strength (YS) of the DP600 steel increases and the ultimate tensile strength (UTS) remains almost unchanged, but the ductility decreases after welding. The DP600 base metal (BM) and WJ are of positive strain rate sensitivity and show similar stress–strain response at all studied strain rates. The enhanced ductility at strain rates ranging from 1 to 100 s{sup −1} is attributed to the retardation of the propagation of plastic strain localization due to the positive strain rate sensitivity and the thermal softening caused by deformation induced adiabatic temperature rise during dynamic tensile deformation. The tensile failure occurs in the inner HAZ of the joint and the distance of failure location from the weld centerline decreases with increasing strain rate. The mechanism for the changing failure location can be related to the different strain rate dependence of the plastic deformation behavior of the microstructures in various regions across the joint. The DP600 WJ absorbs more energy over the whole measured strain rates than that of the BM due to the higher strength at the same strain when the deformation only up to 10% is considered.

  2. Exploiting material softening in hard PZTs for resonant bandwidth enhancement

    Science.gov (United States)

    Leadenham, S.; Moura, A.; Erturk, A.

    2016-04-01

    Intentionally designed nonlinearities have been employed by several research groups to enhance the frequency bandwidth of vibration energy harvesters. Another type of nonlinear resonance behavior emerges from the piezoelectric constitutive behavior for high excitation levels and is manifested in the form of softening stiffness. This material nonlinearity does not result in the jump phenomenon in soft piezoelectric ceramics, e.g. PZT-5A and PZT-5H, due to their large internal dissipation. This paper explores the potential for wideband energy harvesting using a hard (relatively high quality factor) PZT-8 bimorph by exploiting its material softening. A wide range of base excitation experiments conducted for a set of resistive electrical loads confirms the frequency bandwidth enhancement.

  3. Arsenic removal by lime softening

    DEFF Research Database (Denmark)

    Kaosol, T.; Suksaroj, C.; Bregnhøj, Henrik

    2002-01-01

    This paper focuses on the study of arsenic removal for drinking water by lime softening. The initial arsenic (V) concentration was 500 and 1,000 ug/L in synthetic groundwater. The experiments were performed as batch tests with varying lime dosages and mixing time. For the synthetic groundwater......, arsenic (V) removal increased with increasing lime dosage and mixing time, as well as with the resulting pH. The residual arsenic (V) in all cases was lower than the WHO guideline of 10 ug/L at pH higher than 11.5. Kinetic of arsenic (V) removal can be described by a first-order equation as C1 = C0*e......^-k*t. The relation between the constant (k value) and increasing lime dosage was found to be linear, described by k = 0.0034 (Dlime). The results support a theory from the literature that the arsenic (V) was removed by precipitation af Ca3(AsO4)2. The results obtained in the present study suggest that lime...

  4. Synthesis and Performance Properties of Cationic Fabric Softeners Derived from Free Fatty Acid of Tallow Fat.

    Science.gov (United States)

    Mondal, Mithun G; Pratap, Amit Prabhakar

    2016-08-01

    Esterquat cationic softener is basically the class of surface active quaternary ammonium compounds. Esterquat compounds were synthesized and their surface behavior, antibacterial activity and Textile softening properties were investigated. Easily found cheap material was used to synthesize cationic fabric softeners. This fabric softener will be a good for commercially and industrially important because their emulsify activity, rewettability dispersing power and softness. Free fatty acids were derived from tallow oil and were treated with triethanolamine and mono-ethanolamine at 140°C. This diester was quaternaries with dimethyl sulphate and benzyl chloride. The synthesized esterquat compounds were characterized by its cationic content, 1H NMR and FT-IR analysis. In addition to the cationic content, surface tension, CMC (critical micelle concentration), rewettability, fabric softening, emulsification and dispersing power were determined as their surface-active properties. The fabric softening activity of esterquat and esteramide prepared from DMS was better softening activity of fabrics compared to untreated cotton and polyester fabrics cloth. The presented result shows that the esterquat made from BCl exhibit the best dispersing power. The esterquat made from DMS both in TEA and MEA shows good rewettability was determined.

  5. Twinning in weld HAZ of ZK21 commercial magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The microstructure and properties of Mg ZK21 laser beam weld without filler were researched using optical microscopy (OM), electron microscopy and mechanical test. The results show that the fracture strain of the joints after laser beam welding reduces by about 10.7% at room temperature. By means of laser beam welding, the fusion zones contain tensile RS, while the base material far away from the fusion line is under balancing compressive RS. The microstructm-es of the weld were characterized by a narrow heat affected zone and twins. Significant { 10-12 } tension twins occur in the weld HAZ during laser welding processing. Due to the influence of temperature field and stress on morphologies, most of twins form twinning bands, which are nearly parallel to the welding direction.

  6. Pregnancy Constipation: Are Stool Softeners Safe?

    Science.gov (United States)

    Healthy Lifestyle Pregnancy week by week Is it safe to take stool softeners to treat pregnancy constipation? Answers from Roger ... 2014 Original article: http://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/expert-answers/pregnancy-constipation/faq- ...

  7. Nanotwinned fcc metals: Strengthening versus softening mechanisms

    Science.gov (United States)

    Stukowski, A.; Albe, K.; Farkas, D.

    2010-12-01

    The strengthening effect of twins in nanocrystalline metals has been reported both in experiment and simulation. While twins are mostly considered as effective barriers to dislocation slip transfer, they can also provide nucleation sites for dislocations or migrate during the deformation process, thereby contributing to plasticity. By comparing twinned and nontwinned samples, we study the effect of twins on the deformation behavior of nanocrystalline Cu and Pd using atomistic simulations. While Cu shows hardening due to the presence of twins, Pd shows the opposite effect. A quantitative dislocation analysis method is applied, which allows to analyze dislocation interactions with twin planes and grain boundaries and to measure dislocation, stacking fault, and twin-boundary densities as functions of strain. A statistical analysis of the occurring dislocation types provides direct evidence for the role of twin boundaries as effective sources for twinning dislocations, which are the reason for the observed softening in some fcc materials. In addition, we discuss how the orientation of the loading direction with respect to the twin planes affects the response of nanotwinned Cu and Pd.

  8. Flash sintering of dielectric nanoparticles as a percolation phenomenon through a softened film

    Science.gov (United States)

    Chaim, Rachman; Chevallier, Geoffroy; Weibel, Alicia; Estournès, Claude

    2017-04-01

    Recent work [Biesuz et al., J. Appl. Phys. 120, 145107 (2016)] showed analogies between the flash sintering and dielectric breakdown in α-aluminas pre-sintered to different densities. Here, we show that flash sintering of dielectric nanoparticles can be described as a universal behavior by the percolation model. The electrical system is composed of particles and their contact point resistances, the latter softened first due to preferred local Joule heating and thermal runaway during the flash. Local softening has a hierarchical and invasive nature and propagates between the electrodes. The flash event signals the percolation threshold by invasive nature of the softened layer at the particle surfaces. Rapid densification is associated with local particle rearrangements due to attractive capillary forces induced by the softened film at the particle contacts. Flash sintering is a critical phenomenon with a self-organizing character. The experimental electric conductivity results from flash sintering are in full agreement with those calculated from the percolation model.

  9. 桩-筏-土体系的地震软化行为及ABAQUS模拟研究%STUDY OF SEISMIC SOFTENING BEHAVIOR AND ABAQUS SIMULATION OF PILE-RAFT-CLAY SYSTEM

    Institute of Scientific and Technical Information of China (English)

    马亢; 许强

    2012-01-01

    通过开展离心机动力试验,充分揭示在地震荷载的持续作用下,土体将发生一定程度的软化,表现为周期的持续增大;然而基础(筏板)周期和桩身弯矩包络图几乎不发生改变,说明整个桩-筏结构在地震作用下的行为不会类似于土体发生软化(恶化的现象),而是能持续保持稳定,其动力行为主要取决于自身特性如桩身刚度和上部结构传递给筏板的荷载水平(惯性)等,同时土体的动力软化效应对桩-筏结构的影响很小.为了验证试验结果的正确性和合理性,采用ABAQUS 6.9程序对试验结果进行计算分析,土体模型包括软件内嵌的Hypoelastic非线性模型和所开发的考虑动力降强效应的HyperMas用户子程序模型(UMAT).计算结果符合试验实测结果,尤其能准确地捕捉桩身最大弯矩值和周期等重要的工程设计参数.且有侧重于基础单元的地震响应分析,非降强模型和降强模型的计算差异很小,再次说明土体软化对既有桩-筏结构影响很小,但采用非降强模型计算更为快捷、高效.%By conducting dynamic centrifuge tests on the pile-raft-clay system, that soil softening will be taken place in both near field and far field clay in a great degree is investigated, which are manifested as an increase in the resonance periods of clay layers with the level of shaking and successive earthquakes, while this is not the case for the pile-raft foundation since resonance periods of raft and bending moment envelopes of the pile are hardly affected by earthquake loadings. Furthermore, pile-raft dynamic behavior is hardly affected by the stiffness degradation of surrounding clay and could keep stable in successive earthquakes process. Then centrifuge tests are back-analyzed by using ABAQUS 6.9. The results show that, which are conducted using Hypoelastic model embedded in ABAQUS and a developed constitutive relationship, gave reasonably good agreement with the

  10. Prediction of HAZ grain size in welding of ultra fine grained steel with different parameters

    Institute of Scientific and Technical Information of China (English)

    Zhao Hongyun; Zhang Hongtao; Li Dongqing; Wang Guodong

    2010-01-01

    The temperature field and thermal cycling curve in the heat-affected zone during welding 400 MPa ultra fine grained steel by plasma arc were simulated using finite element method.The principle of grain growth kinetics was used to predict the grain size in the heat-affected zone under different welding parameters.The simulation results show that the growing tendency of HAZ grain could be controlled by adjusting the welding parameters,but the growth of HAZ grain could not be eliminated at all.The HAZ grain size became small with increasing of the cooling rate and added with increasing of welding current,arc voltage and welding speed.

  11. A nonlocal constitutive model for trabecular bone softening in compression.

    Science.gov (United States)

    Charlebois, Mathieu; Jirásek, Milan; Zysset, Philippe K

    2010-10-01

    Using the three-dimensional morphological data provided by computed tomography, finite element (FE) models can be generated and used to compute the stiffness and strength of whole bones. Three-dimensional constitutive laws capturing the main features of bone mechanical behavior can be developed and implemented into FE software to enable simulations on complex bone structures. For this purpose, a constitutive law is proposed, which captures the compressive behavior of trabecular bone as a porous material with accumulation of irreversible strain and loss of stiffness beyond its yield point and softening beyond its ultimate point. To account for these features, a constitutive law based on damage coupled with hardening anisotropic elastoplasticity is formulated using density and fabric-based tensors. To prevent mesh dependence of the solution, a nonlocal averaging technique is adopted. The law has been implemented into a FE software and some simple simulations are first presented to illustrate its behavior. Finally, examples dealing with compression of vertebral bodies clearly show the impact of softening on the localization of the inelastic process.

  12. A FRACTURE-ENERGY-BASED ELASTO-SOFTENING-PLASTIC CONSTITUTIVE MODEL FOR JOINTS OF GEOMATERIALS

    Institute of Scientific and Technical Information of China (English)

    沈新普; 沈国晓

    2002-01-01

    On the basis of plasticity and fracture mechanics for quasi- brittle materials, this article presented a constitutive model for gradual softening behavior of joints of geomaterials. Corresponding numerical tests are carried out at the local level. Characteristics of the model proposed are 1 ) plastic softening and dilatancy behavior are directly related to the fracture process of joint, and much less material and model parameters are required compared with those proposed by references; 2) the process of decohesion coupled with friction al sliding at both micro-scale and macro-scale is described.

  13. Transition region fracture toughness and microstructural alterations in the weld HAZ of RPV steel

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Hak Soo; Chung, In Sang [Kyungpook National Univ., Taegu (Korea, Republic of); Kim, Joo Hak; Hong, Jun Hwa; Moon, Jong Gul [KAERI, Taejon (Korea, Republic of)

    1999-10-01

    The fracture toughness of the thermal cycle simulated weld HAZ(Heat-Affected-Zone) of SA 508 C1.3 RPV(Reactor Pressure Vessel) steel was evaluated in the ductile-brittle transition region. Reference temperature(T{sub 0}), and master curve for each region in the weld HAZ were determined from the three point bending tests at low temperatures, by using the Weibull's statistical method as described in ASTM E1921. Most specimens were conformed to validate at the test temperatures. It was shown that the new test method, which evaluates the fracture toughness in the transition region, was effectively applicable to the weld HAZ. The fracture toughness test results indicated that the coarse grained HAZ region near the weld fusion line possesses relatively good fracture toughness. In contrast, the minimum toughness value was noted at the subcritically reheated HAZ region adjacent to the base metal. The volume fraction of tempered martensite, mean sizes of grains and precipitates were quantitatively analysed as microstructural factors, a discussion on the effects of these factors on fracture toughness of the weld HAZ is presented.

  14. Softening and elution of monomers in ethanol

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Asmussen, Erik; Munksgaard, E Christian;

    2009-01-01

    The purpose of this study was to investigate the effect of light-curing protocol on softening and elution of monomers in ethanol as measured on a model polymer. It was a further aim to correlate the measured values with previously reported data on degree of conversion and glass transition tempera...

  15. Multi-scale modeling of softening materials

    NARCIS (Netherlands)

    Lloberas Valls, O.; Simone, A.; Sluys, L.J.

    2008-01-01

    This paper presents an assessment of a two-scale framework for the study of softening materials. The procedure is based on a hierarchical Finite Element (FE) scheme in which computations are performed both at macro and mesoscopic scale levels. The methodology is chosen specifically to remain valid

  16. Constitutive Model for Multiaxial Ratcheting Predictions of Cyclic Softening Weld Metal

    Institute of Scientific and Technical Information of China (English)

    GAO Hong; CHEN Xu; JIAO Rong

    2005-01-01

    A series of fully reversed axial, torsional strain-controlled cyclic tests and two multiaxial ratcheting tests were conducted on weld metal specimens using an Instron8521 tension-torsional servo-controlled testing machine. The weld metal showed clear cyclic softening under axial, torsional and multiaxial loading. A modified kinematic hardening rule was proposed in which a multiaxial-loading-dependent parameter incorporated the radial evanescence term of the Burlet-Cailletaud mode with the Ohno-Wang kinematic hardening rule to predict the multiaxial ratcheting effects. The introduction of yield stress evolved with accumulated plasticity strain enables the model to predict cyclic plasticity behavior of cyclic softening or cyclic hardening materials. Thus modified model considers the isotropic hardening as well as kinematic hardening of yield surface, and it can present description of plasticity behavior and ratcheting of cyclic softening and cyclic hardening materials well under multiaxial loading.

  17. Development of a design methodology for high temperature cyclic applications of materials which experience cyclic softening

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, D.L.; Stubbins, J.F. (Illinois Univ., Urbana, IL (USA). Dept. of Mechanical and Industrial Engineering)

    1988-12-01

    The project has as its original focus the high temperature behavior of 2.25 Cr-1 Mo steel, heat treated to produce a predominantly bainitic microstructure and the load carrying response of components made of this material. Experiments were carried out on uniform and notched specimens under both steady and cyclic loading using specially acquired electromechanical test machines. It emerged that a very important feature of mechanical behavior under the conditions of interest was the strong tendency of this material to cyclically soften, particularly at high temperature in the creep range, giving the illusion of a severe creep-fatigue interaction under certain conditions. This finding led to a significant component of the project being devoted to investigation of the effects of local, as opposed to generalized, cyclic softening, and the implications this phenomenon might have on the setting of allowable design stress limits. The format of this report is as follows: The second chapter is a review of the work carried out in approximately chronological order under the headings of work was carried out under the following: (1) 2.25 Cr 1 Mo Steel -- Elevated Temperature Fatigue and Environmental Effects; (2) Preliminary Studies of Advanced Austenitics; (3) A Uniaxial Constitutive Model for Cyclic Softening; (4) The Iso-Cyclic Stress-Strain Approach to Evaluation of Components in Cyclic Softening Materials; (5) Testing of High Temperature Austenitic Alloys; and (6) Design Methodology for Aging Materials -- Application to Cyclic Softening. 65 refs., 39 figs., 7 tabs.

  18. Water Softeners: How Much Sodium Do They Add?

    Science.gov (United States)

    ... softened water, you may want to consider a water-purification system that uses potassium chloride instead. Another option is to soften only the hot water and use unsoftened cold water for drinking and ...

  19. Fracture Mechanics of an Elastic Softening Material like Concrete

    NARCIS (Netherlands)

    Reinhardt, H.W.

    1984-01-01

    Concrete is modelled as a linear elastic softening material and introduced into fracture mechanics. A discrete crack is considered with softening zones at the crack tips. Following the approach of Dugdale/Barenblatt, closing stresses are applied to the crack faces in the softening zone. The stresses

  20. Microstructure characterization and weldability evaluation of the weld heat affected zone (HAZ) in 310HCbN tubing

    Energy Technology Data Exchange (ETDEWEB)

    Lundin, C.D.; Qiao, C.Y.P. [Univ. of Tennessee, Knoxville, TN (United States)

    1995-08-01

    Metallographic evaluation on the Gleeble simulated HAZ samples of 310HCbN tubing material was performed in order to reveal potential degradation in mechanical properties and corrosion resistance. The carbide evolutionary process in the HAZ samples was studied. It is indicated that 310HCbN material showed a weld HAZ sensitization tendency that is associated with the formation of Cr{sub 23}C{sub 6}.

  1. Pressure induced elastic softening in framework aluminosilicate- albite (NaAlSi3O8)

    Science.gov (United States)

    Mookherjee, Mainak; Mainprice, David; Maheshwari, Ketan; Heinonen, Olle; Patel, Dhenu; Hariharan, Anant

    2016-10-01

    Albite (NaAlSi3O8) is an aluminosilicate mineral. Its crystal structure consists of 3-D framework of Al and Si tetrahedral units. We have used Density Functional Theory to investigate the high-pressure behavior of the crystal structure and how it affects the elasticity of albite. Our results indicate elastic softening between 6-8 GPa. This is observed in all the individual elastic stiffness components. Our analysis indicates that the softening is due to the response of the three-dimensional tetrahedral framework, in particular by the pressure dependent changes in the tetrahedral tilts. At pressure Mohorovicic discontinuity in thickened continental crustal regions.

  2. Lattice softening in body-centered-cubic lithium-magnesium alloys

    Science.gov (United States)

    Winter, I. S.; Tsuru, T.; Chrzan, D. C.

    2017-08-01

    A first-principles investigation of the influence of lattice softening on lithium-magnesium alloys near the body-centered-cubic (bcc)/hexagonal close-packed (hcp) transition composition is presented. Results show that lithium-magnesium alloys display a softening of the shear modulus C11-C12 , and an acoustic phonon branch between the Γ and N high symmetry points, as the composition approaches the stability limit for the bcc phase. This softening is accompanied by an increase in the size of the dislocation core region. Ideal tensile strength calculations predict that ordered phases of lithium-magnesium alloys are intrinsically brittle. Methods to make the alloys more ductile are discussed, and the propensity for these alloys to display gum-metal-like behavior is assessed.

  3. Correlation between tension softening relation and crack extension resistance in concrete

    Institute of Scientific and Technical Information of China (English)

    Xiufang ZHANG; Shilang XU

    2009-01-01

    Changes of the material fracture toughness with crack propagation can be described by a crack extension resistance curve, one of the fundamental fracture criteria in crack mechanics. Recently, experimental observation of the fracture behavior in concrete was used to develop a new fracture criterion, the crack extension GR resistance curve, to analyze crack propagation during the entire concrete fracture process. The variation of the crack extension resistance is mainly associated with the energy consumption in the fracture process zone ahead of the stress-free crack tip. The crack extension resistance is then a function of the softening curve, which is a basic mechanical property in the fracture process zone. The relationship between the softening curve and the crack extension GR resistance curve is then analyzed based on results of three-point bending beams tests. The results indicate that the characteristic points of the crack extension resistance GR curve is closely related to the characteristic point on used tension softening curve.

  4. Influence of heat input on HAZ liquation cracking in laser welded GH909 alloy

    Science.gov (United States)

    Yan, Fei; Hu, Chongjing; Zhang, Xiong; Cai, Yuanzheng; Wang, Chunming; Wang, Jun; Hu, Xiyuan

    2017-07-01

    In this paper, we describe influence of heat input on HAZ liquation cracking in laser welded GH909 alloy. The results demonstrated that more cracks were produced using high laser power and welding speed. The presence of cracks greatly weakened the hot ductility of this material and the binding force between the adjacent grains, resulting in reducing the tensile strength of welded joints. The occurrence of HAZ cracking was mainly attributable to the coarseness of microstructures and large tensile stresses. A new method was proposed to prevent HAZ liquation cracking using low laser power and welding speed at a constant heat input. The simulated results were consistent with the experimental results, verifying the correctness and feasibility of the method.

  5. Influence of cooling conditions on X70 pipeline steel in-service welding HAZ

    Institute of Scientific and Technical Information of China (English)

    Jin Haicheng; Wang Yong; Han Bin; Chen Yuhua

    2006-01-01

    The chamber device was designed and set up to simulate the in-service welding. The results show: the ts/5, t8/3 and inner wall peak temperature Tp decrease with the cooling rate increases. The welding energy is carried off by flowing medium,the cooling rate increases, and many unbalanced microstructures such as granular bainite, martensite and M-A generate; it worsens the properties of HAZ. Under air-cooling, the cooling rate is slow, the austenite grain grows obviously , the lath ferrite crosses the whole austenite, and it causes the hardness value is also big. The change of HAZ width is not obvious with the increase of cooling rate; and burn-through is not susceptible to the cooling rate. The quench microstructures increase and the hydrogen does not outflow from the HAZ easily when increase the cooling rate, so the susceptibility of hydrogen cracking increases.

  6. Softening in random networks of non-identical beams

    Science.gov (United States)

    Ban, Ehsan; Barocas, Victor H.; Shephard, Mark S.; Picu, R. Catalin

    2016-02-01

    Random fiber networks are assemblies of elastic elements connected in random configurations. They are used as models for a broad range of fibrous materials including biopolymer gels and synthetic nonwovens. Although the mechanics of networks made from the same type of fibers has been studied extensively, the behavior of composite systems of fibers with different properties has received less attention. In this work we numerically and theoretically study random networks of beams and springs of different mechanical properties. We observe that the overall network stiffness decreases on average as the variability of fiber stiffness increases, at constant mean fiber stiffness. Numerical results and analytical arguments show that for small variabilities in fiber stiffness the amount of network softening scales linearly with the variance of the fiber stiffness distribution. This result holds for any beam structure and is expected to apply to a broad range of materials including cellular solids.

  7. Hardening by annealing and softening by deformation in nanostructured metals

    DEFF Research Database (Denmark)

    Huang, X.; Hansen, N.; Tsuji, N.

    2006-01-01

    -dislocation and dislocation-interface reactions, such that heat treatment reduces the generation and interaction of dislocations, leading to an increase in strength and a reduction in ductility. A subsequent deformation step may restore the dislocation structure and facilitate the yielding process when the metal is stressed......We observe that a nanostructured metal can be hardened by annealing and softened when subsequently deformed, which is in contrast to the typical behavior of a metal. Microstructural investigation points to an effect of the structural scale on fundamental mechanisms of dislocation....... As a consequence, the strength decreases and the ductility increases. These observations suggest that for materials such as the nanostructured aluminum studied here, deformation should be used as an optimizing procedure instead of annealing....

  8. Seed softening patterns of forage legumes in a temperate/subtropical environment in Uruguay

    Directory of Open Access Journals (Sweden)

    Javier Do Canto

    2013-03-01

    their seed softening behavior is likely to be substantially modified in these summer moist environments.

  9. Complete Genome Sequence of Mycoplasma bovigenitalium Strain HAZ 596 from a Bovine Vagina in Japan

    Science.gov (United States)

    Nagai, Kazuya; Murakami, Kenji

    2017-01-01

    ABSTRACT Mycoplasma bovigenitalium, a mycoplasmal species involved in various bovine diseases, including genital disease and mastitis, is also a commensal microorganism that inhabits the bovine genital organs. We present here the complete 853,553-bp genome sequence of M. bovigenitalium strain HAZ 596, which was isolated from a bovine vagina in Japan. PMID:28183755

  10. Relation between occupation in the first coordination shells and Widom line in core-softened potentials.

    Science.gov (United States)

    Salcedo, Evy; Barraz, Ney M; Barbosa, Marcia C

    2013-04-28

    Three core-softened families of potentials are checked for the presence of density and diffusion anomalies. These potentials exhibit a repulsive core with a softening region and at larger distances an attractive well. We found that the region in the pressure-temperature phase diagram in which the anomalies are present increases if the slope between the core-softened scale and the attractive part of the potential decreases. The anomalous region also increases if the range of the core-softened or of the attractive part of the potential decreases. We also show that the presence of the density anomaly is consistent with the non-monotonic changes of the radial distribution function at each one of the two scales when temperature and density are varied. Then, using this anomalous behavior of the structure we show that the pressure and the temperature at which the radial distribution function of one of the two length scales equals the radial distribution function of the other length scales identify the Widom line.

  11. Medium-induced color flow softens hadronization

    CERN Document Server

    Beraudo, A; Wiedemann, U A

    2012-01-01

    Medium-induced parton energy loss, resulting from gluon exchanges between the QCD matter and partonic projectiles, is expected to underly the strong suppression of jets and high-$p_T$ hadron spectra observed in ultra-relativistic heavy ion collisions. Here, we present the first color-differential calculation of parton energy loss. We find that color exchange between medium and projectile enhances the invariant mass of energetic color singlet clusters in the parton shower by a parametrically large factor proportional to the square root of the projectile energy. This effect is seen in more than half of the most energetic color-singlet fragments of medium-modified parton branchings. Applying a standard cluster hadronization model, we find that it leads to a characteristic additional softening of hadronic spectra. A fair description of the nuclear modification factor measured at the LHC may then be obtained for relatively low momentum transfers from the medium.

  12. Controlled toothbrush abrasion of softened human enamel.

    Science.gov (United States)

    Voronets, J; Jaeggi, T; Buergin, W; Lussi, A

    2008-01-01

    The aim of this in vitro study was to compare toothbrush abrasion of softened enamel after brushing with two (soft and hard) toothbrushes. One hundred and fifty-six human enamel specimens were indented with a Knoop diamond. Salivary pellicle was formed in vitro over a period of 3 h. Erosive lesions were produced by means of 1% citric acid. A force-measuring device allowed a controlled toothbrushing force of 1.5 N. The specimens were brushed either in toothpaste slurry or with toothpaste in artificial saliva for 15 s. Enamel loss was calculated from the change in indentation depth of the same indent before and after abrasion. Mean surface losses (95% CI) were recorded in ten treatment groups: (1) soft toothbrush only [28 (17-39) nm]; (2) hard toothbrush only [25 (16-34) nm]; (3) soft toothbrush in Sensodyne MultiCare slurry [46 (27-65) nm]; (4) hard toothbrush in Sensodyne MultiCare slurry [45 (24-66) nm]; (5) soft toothbrush in Colgate sensation white slurry [71 (55-87) nm]; (6) hard toothbrush in Colgate sensation white slurry [85 (60-110) nm]; (7) soft toothbrush with Sensodyne MultiCare [48 (39-57) nm]; (8) hard toothbrush with Sensodyne MultiCare [40 (29-51) nm]; (9) soft toothbrush with Colgate sensation white [51 (37-65) nm]; (10) hard toothbrush with Colgate sensation white [52 (36-68) nm]. Neither soft nor hard toothbrushes produced significantly different toothbrush abrasion of softened human enamel in this model (p > 0.05). Copyright 2008 S. Karger AG, Basel.

  13. Early stiffening and softening of collagen: interplay of deformation mechanisms in biopolymer networks.

    Science.gov (United States)

    Kurniawan, Nicholas A; Wong, Long Hui; Rajagopalan, Raj

    2012-03-12

    Collagen networks, the main structural/mechanical elements in biological tissues, increasingly serve as biomimetic scaffolds for cell behavioral studies, assays, and tissue engineering, and yet their full spectrum of nonlinear behavior remains unclear. Here, with self-assembled type-I collagen as model, we use metrics beyond those in standard single-harmonic analysis of rheological measurements to reveal strain-softening and strain-stiffening of collagen networks both in instantaneous responses and at steady state. The results show how different deformation mechanisms, such as deformation-induced increase in the elastically active fibrils, nonlinear extension of individual fibrils, and slips in the physical cross-links in the network, can lead to the observed complex nonlinearity. We demonstrate how comprehensive rheological analyses can uncover the rich mechanical properties of biopolymer networks, including the above-mentioned softening as well as an early strain-stiffening, which are important for understanding physiological response of biological materials to mechanical loading.

  14. Flash sintering of dielectric nanoparticles as a percolation phenomenon through a softened film

    OpenAIRE

    Chaim, Rachman; Chevallier, Geoffroy; Weibel, Alicia; Estournès, Claude

    2017-01-01

    International audience; Recent work [Biesuz et al., J. Appl. Phys. 120, 145107 (2016)] showed analogies between the flash sintering and dielectric breakdown in α-aluminas pre-sintered to different densities. Here, we show that flash sintering of dielectric nanoparticles can be described as a universal behavior by the percolation model. The electrical system is composed of particles and their contact point resistances, the latter softened first due to preferred local Joule heating and thermal ...

  15. Estimation of the most influential factors on the laser cutting process heat affected zone (HAZ) by adaptive neuro-fuzzy technique

    Science.gov (United States)

    Petković, Dalibor; Nikolić, Vlastimir; Milovančević, Miloš; Lazov, Lyubomir

    2016-07-01

    Heat affected zone (HAZ) of the laser cutting process may be developed on the basis on combination of different factors. In this investigation was analyzed the HAZ forecasting based on the different laser cutting parameters. The main aim in this article was to analyze the influence of three inputs on the HAZ of the laser cutting process. The method of ANFIS (adaptive neuro fuzzy inference system) was applied to the data in order to select the most influential factors for HAZ forecasting. Three inputs are considered: laser power, cutting speed and gas pressure. According the results the cutting speed has the highest influence on the HAZ forecasting (RMSE: 0.0553). Gas pressure has the smallest influence on the HAZ forecasting (RMSE: 0.0801). The results can be used in order to simplify HAZ prediction and analyzing.

  16. Effect of weld heat input on toughness and structure of HAZ of a new super-high strength steel

    Indian Academy of Sciences (India)

    Wang Juan; Li Yajiang; Liu Peng

    2003-04-01

    Fracture morphology and fine structure in the heat-affected zone (HAZ) of HQ130 super-high strength steel are studied by means of SEM, TEM and electron diffraction technique. Test results indicated that the structure of HAZ of HQ130 steel was mainly lath martensite (ML), in which there were a lot of dislocations in the sub-structure inside ML lath, the dislocation density was about (0.3 ∼ 0.9) × 1012/cm2. No obvious twin was observed in the HAZ under the condition of normal weld heat input. By controlling weld heat input ($E \\leq$ 20 kJ/cm), the impact toughness in the HAZ can be assured.

  17. Enzyme catalyzed electricity-driven water softening system.

    Science.gov (United States)

    Arugula, Mary A; Brastad, Kristen S; Minteer, Shelley D; He, Zhen

    2012-12-10

    Hardness in water, which is caused by divalent cations such as calcium and magnesium ions, presents a major water quality problem. Because hard water must be softened before use in residential applications, there is great interest in the saltless water softening process because, unlike ion exchange softeners, it does not introduce additional ions into water. In this study, a saltless hardness removal driven by bioelectrochemical energy produced through enzymatic oxidation of glucose was proposed and investigated. Glucose dehydrogenase was coated on a carbon electrode to catalyze glucose oxidation in the presence of NAD⁺ as a cofactor/mediator and methylene green as an electrocatalyst. The results showed that electricity generation stimulated hardness removal compared with non-electricity conditions. The enzymatic water softener worked upon a 6h batch operation per day for eight days, and achieved an average hardness removal of 46% at a high initial concentration of 800 mg/L as CaCO₃. More hardness was removed at a lower initial concentration. For instance, at 200mg/L as CaCO₃ the enzymatic water softener removed 76.4±4.6% of total hardness. The presence of magnesium ions decreased hardness removal because of its larger hydrated radius than calcium ions. The enzymatic water softener removed 70-80% of total hardness from three actual hard water samples. These results demonstrated a proof-of-concept that enzyme catalyzed electricity generation can be used to soften hard water.

  18. Light color, low softening point hydrocarbon resins

    Energy Technology Data Exchange (ETDEWEB)

    Evans, M.L.; Hentges, S.G.

    1990-06-12

    This patent describes a hydrocarbon resin having a softening point of from 0{degrees} C to about 40{degrees} C, a Gardner color of about 7 or less, a number average molecular weight (Mn) of from about 100 to about 600, and a M{sub {ital w}}/M{sub {ital n}} ratio of from about 1.1 to about 2.7, prepared by Friedel Crafts polymerization of a hydrocarbon feed. It comprises: from about 5% to about 75% by weight of a C{sub 8} to C{sub 10} vinyl aromatic hydrocarbon stream; up to about 35% by weight of a piperylene stream; and from about 25% to about 70% by weight of a stream containing C{sub 4} to C{sub 8} monoolefin chain transfer agent of the formula RR{prime}C {double bond} CR{double prime}R triple{prime} where R and R{prime} are C{sub 1} to C{sub 5} alkyl, R{double prime} and R triple{prime} are independently selected from H and a C{sub 1} to C{sub 4} alkyl group.

  19. High Temperature Softening Behaviors and Flow Stress Model for a High Molybdenum Austenitic Stainless Steel%高钼奥氏体不锈钢高温软化行为与流变应力模型

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Single-stage and double-stage interrupted hot compression tests for physical simulating hot rolling have been carried out on the THERMECMATSTOR-Z simulator for 00Cr20Ni18Mo6Cu[ N] austenitic stainless steel under high temperature (1223~1373 K) and various strain rates (0.1~60 s- 1 ). The high temperature mechanical behaviors and microstructure evolution of the steel were studied. The activation energies of hot deformation and dynamic, static and metadynamic recrystallization were calculated. Serials of perfect flow stress model considering dynamic recrystallization were established. The predicted result by the model was well agreed with the experiment data.The kinetics of metadynamic and static recrystallization had also been determined.

  20. The effect of hardening laws and thermal softening on modeling residual stresses in FSW of aluminum alloy 2024-T3

    DEFF Research Database (Denmark)

    Sonne, Mads Rostgaard; Tutum, Cem Celal; Hattel, Jesper Henri;

    2013-01-01

    or kinematic hardening together with the metallurgical softening model were applied in order to give a first impression of the tendencies in residual stresses in friction stir welds when choosing different hardening and softening behaviors. Secondly, real friction stir butt welding of aluminum alloy 2024-T3...... were simulated and compared with experimentally obtained results for both temperatures and residual stresses (using the slitting method). The comparisons showed good agreement regarding temperatures whereas the residual stress comparisons indicated different sensitivities for the cold and hot welding...

  1. Analysis of pile load-transfer under pile-side softening

    Institute of Scientific and Technical Information of China (English)

    刘杰; 张可能

    2003-01-01

    A set of analytical equations for the variation of the axial force along depth and the pile-top load-settle-ment curve were established, using tri-linear softening model to pile-side soil and bilinear hardening model to pile-end soil . Influences of the pile-side and pile-end soil behavior on the load-settlement curve were discussed, indica-ting that the lowering reason for the variation step degree of the axial force along depth is the softening of the pile-side soil to result in the side friction lowering when the pile-top load is increased. To verify the reliability of thismethod, the parameters used in calculation are obtained from the test in Zhuzhou area. The obtained results are thencompared with the tested results. Contrast shows that the calculated results and the tested values are very close,which illustrates that the proposed method is reliable.

  2. Ratcheting induced cyclic softening behaviour of 42CrMo4 steel

    Science.gov (United States)

    Kreethi, R.; Mondal, A. K.; Dutta, K.

    2015-02-01

    Ratcheting is an important field of fatigue deformation which happens under stress controlled cyclic loading of materials. The aim of this investigation is to study the uniaxial ratcheting behavior of 42CrMo4 steel in annealed condition, under various applied stresses. In view of this, stress controlled fatigue tests were carried out at room temperature up to 200 cycles using a servo-hydraulic universal testing machine. The results indicate that accumulation of ratcheting strain increases monotonically with increasing maximum applied stress however; the rate of strain accumulation attains a saturation plateau after few cycles. The investigated steel shows cyclic softening behaviour under the applied stress conditions. The nature of strain accumulation and cyclic softening has been discussed in terms of dislocation distribution and plastic damage incurred in the material.

  3. Unusual phonon softening in the Kondo lattice CeCu 2

    Science.gov (United States)

    Loewenhaupt, Michael; Witte, Ulrike; Kramp, Sirko; Braden, Markus; Svoboda, Pavel

    2002-03-01

    CeCu2 is a Kondo lattice with antiferromagnetic order below 3.5 K and a Kondo temperature of about 6 K. Earlier neutron scattering experiments lead to the assumption of a coupling between a crystal field transition and some phonons with energies around 14 meV. With the results from our newly performed inelastic neutron measurements on a single crystal we found these assumptions confirmed. We observed an unusual softening of certain phonons with increasing temperature. This softening of up to 15% is much stronger than the normal thermal behavior of phonons. Additionally, the line width of these phonons is increasing. At the same time the magnetic response is strongly broadened by the coupling to the phonons. The findings for CeCu2 are discussed in relation with similar observation of a coupling between electronic and lattice degrees of freedom in CeAl2 and YbPO4.

  4. Genetic improvement of tomato by targeted control of fruit softening

    KAUST Repository

    Uluisik, Selman

    2016-07-25

    Controlling the rate of softening to extend shelf life was a key target for researchers engineering genetically modified (GM) tomatoes in the 1990s, but only modest improvements were achieved. Hybrids grown nowadays contain \\'non-ripening mutations\\' that slow ripening and improve shelf life, but adversely affect flavor and color. We report substantial, targeted control of tomato softening, without affecting other aspects of ripening, by silencing a gene encoding a pectate lyase. © 2016 Nature America, Inc. All rights reserved.

  5. Mechanical Properties and Microstructures of the HAZs of 11Cr F/M Steel for Gen-IV Nuclear Power Station

    Science.gov (United States)

    Li, Yongkui; Wang, Jian; Lu, Shanping; Rong, Lijian; Li, Dianzhong

    2015-02-01

    The weldability of a newly developed 11Cr ferritic/martensitic (F/M) steel to be used in Pb-Bi liquid cooled ADS for the fourth generation nuclear power station was studied by experiments and numerical simulation. In this work, an appropriate method for obtaining simulated heat-affected zones (HAZs) was developed. HAZs, including CG-HAZ, FG-HAZ, and IC-HAZ, were successfully simulated by Gleeble at heating rates of 209, 176, and 149 °C/s and peak temperatures of 1314, 1138, and 998 °C, respectively. Results of tension and impact tests indicated that the simulated HAZs had much higher strength and poorer toughness than the base metal. The poor toughness is caused by high carbon, silicon contents, and quenched martensitic microstructures. The tempering treatment is necessary for the developed steel before application in nuclear reactor.

  6. Rigid proteins and softening of biological membranes—with application to HIV-induced cell membrane softening

    Science.gov (United States)

    Agrawal, Himani; Zelisko, Matthew; Liu, Liping; Sharma, Pradeep

    2016-05-01

    A key step in the HIV-infection process is the fusion of the virion membrane with the target cell membrane and the concomitant transfer of the viral RNA. Experimental evidence suggests that the fusion is preceded by considerable elastic softening of the cell membranes due to the insertion of fusion peptide in the membrane. What are the mechanisms underpinning the elastic softening of the membrane upon peptide insertion? A broader question may be posed: insertion of rigid proteins in soft membranes ought to stiffen the membranes not soften them. However, experimental observations perplexingly appear to show that rigid proteins may either soften or harden membranes even though conventional wisdom only suggests stiffening. In this work, we argue that regarding proteins as merely non-specific rigid inclusions is flawed, and each protein has a unique mechanical signature dictated by its specific interfacial coupling to the surrounding membrane. Predicated on this hypothesis, we have carried out atomistic simulations to investigate peptide-membrane interactions. Together with a continuum model, we reconcile contrasting experimental data in the literature including the case of HIV-fusion peptide induced softening. We conclude that the structural rearrangements of the lipids around the inclusions cause the softening or stiffening of the biological membranes.

  7. Rigid proteins and softening of biological membranes-with application to HIV-induced cell membrane softening.

    Science.gov (United States)

    Agrawal, Himani; Zelisko, Matthew; Liu, Liping; Sharma, Pradeep

    2016-05-06

    A key step in the HIV-infection process is the fusion of the virion membrane with the target cell membrane and the concomitant transfer of the viral RNA. Experimental evidence suggests that the fusion is preceded by considerable elastic softening of the cell membranes due to the insertion of fusion peptide in the membrane. What are the mechanisms underpinning the elastic softening of the membrane upon peptide insertion? A broader question may be posed: insertion of rigid proteins in soft membranes ought to stiffen the membranes not soften them. However, experimental observations perplexingly appear to show that rigid proteins may either soften or harden membranes even though conventional wisdom only suggests stiffening. In this work, we argue that regarding proteins as merely non-specific rigid inclusions is flawed, and each protein has a unique mechanical signature dictated by its specific interfacial coupling to the surrounding membrane. Predicated on this hypothesis, we have carried out atomistic simulations to investigate peptide-membrane interactions. Together with a continuum model, we reconcile contrasting experimental data in the literature including the case of HIV-fusion peptide induced softening. We conclude that the structural rearrangements of the lipids around the inclusions cause the softening or stiffening of the biological membranes.

  8. Rock softening due to ultrasonic acoustical energy

    Science.gov (United States)

    Freund, F. T.; Freund, M. M.; Hedberg, C. M.; Haller, K. C.; Dahlgren, R.; Williams, C.; Agrawal, P.

    2011-12-01

    When igneous or high-grade metamorphic rocks are subjected to deviatoric stresses, dormant defects existing in the matrix of common rock-forming minerals become activated releasing mobile positive hole charge carriers. These defects consist of pairs of oxygen anions in the 1- valence state, e.g. peroxy links such as O3Si-OO-SiO3. When the peroxy bond breaks, O3Si-O:O-SiO3, an electron is transferred from a neighboring O2- creating a trapped electron defect, O3Si-O.O-SiO3, while the donor oxygen, now O-, turns into a defect electron or hole that can propagate as a highly mobile positive charge traveling along the upper edge of the valence band. There is evidence that the wave function associated with these positive hole charge carriers is highly delocalized. The delocalization lowers the electron density at the surrounding O2-, hence the bond energy, thereby affecting fundamental properties including the mechanical strength. To demonstrate the rock softening effect we mounted a rectangular bar of fine-grained gabbro about 30 cm long in a horizontal position clamping it at one end. A piezoelectric transducer (PZT) was epoxied to the fixed end of the rock bar to send ultrasonic energy at 57 KHz toward the cantilevered end. The downward deflection of the free end of the beam was measured with an interferometer to a high degree of precision. With ultrasonic energy present, the free end of the beam sagged near-instantaneously by about 0.2 μm and continued to sag slowly by about 0.4 μm over 120 sec. Upon turning off the PZT the rock bar returned slowly to the baseline deflection value. The ultrasound waves generated by the PZT activate positive holes, changing the apparent stiffness of the beam and causing its cantilevered end to bend downward. We also conducted experiments using an Instron 5569 Dual Column Testing System to subject rectangular plates (15.2 x 3.8 x 0.5 cm) of the same gabbro to dynamic three-point flexural tests. Using electrostatic fields of different

  9. The modeling of heat affected zone (HAZ in submerged arc welding (SAW surfacing steel element

    Directory of Open Access Journals (Sweden)

    J. Winczek

    2016-04-01

    Full Text Available In the work the bimodal heat source model in the description of the temperature field is presented. The electric arc was treated physically as one heat source, whose heat was divided: part of the heat is transferred by the direct impact of the electric arc, but another part of the heat is transferred to the weld by the melted material of the electrode. Computations of the temperature field during SAW surfacing of S355 steel element are carried out. The macrographic and metallographic analysis of the weld confirmed the depth and shapes of the fusion line and HAZ defined by the numerical simulation.

  10. Cefalometría 3D mediante tomografía computarizada de haz de cono

    OpenAIRE

    Montoto González, Gloria

    2015-01-01

    La cefalometría es una herramienta clínica de investigación esencial en la ortodoncia. Las imágenes en dos dimensiones tienen una serie de desventajas entre ellas la falta de perspectiva, errores en la proyección, superposición de estructuras, artefactos en la imagen, magnificación o errores de posición de la cabeza. La tomografía computarizada de haz de cono (TCCB) nos ofrece una alternativa a sistemas tradicionales de TC con ciertas ventajas como menor radiación y menor coste. OBJET...

  11. Microstructure and mechanical property in heat affected zone (HAZ in F82H jointed with SUS316L by fiber laser welding

    Directory of Open Access Journals (Sweden)

    S. Kano

    2016-12-01

    Full Text Available This study investigates the microstructure and mechanical property in heat affected zone (HAZ between F82H and SUS316L jointed by 4 kW fiber laser welding at different parameters such as laser scan rate and beam position. OM/FE-SEM observation, EPMA analysis and nano-indentation hardness test were utilized to characterize the microstructure and evaluate the mechanical property. Results show that the HAZ width is dependent on the welding condition. The precipitation of M23C6 particle in HAZ is found to be closely related to the distance from WM/HAZ interface. Decrease in Cr and C concentration in M23C6 depended on the welding condition; the decrease was relatively milder in the case of shifting the beam position to SUS side. Furthermore, the rapid increment in nano-indentation hardness, i.e. ≈2500 MPa, at HAZ/F82H interface was observed regardless of welding parameters. The temperatures at HAZ/F82H interface were estimated from Cr and C concentration change of M23C6 by EPMA. It was revealed that the temperature of HAZ/F82H interface increased with increasing HAZ width, and that the presence of over-tempered HAZ (THAZ region is confirmed only in the specimens welded right on the F82H/SUS interface (no-shift at the laser scan rate of 3 m/min.

  12. Comportamento respiratório e amaciamento de graviola (Annona muricata L. Após tratamentos pós-colheita com cera e 1-metilciclopropeno Respiratory behavior and softening of soursop fruit (Annona muricata L. after postharvest treatments with wax and 1-methylcyclopropene

    Directory of Open Access Journals (Sweden)

    Maria Auxiliadora Coêlho de Lima

    2010-02-01

    Full Text Available Avaliou-se o efeito da aplicação pós-colheita de 1-metilciclopropeno (1-MCP e cera sobre o comportamento respiratório e as mudanças bioquímicas associadas ao amaciamento de graviola 'Morada', durante o armazenamento refrigerado. Os frutos, produzidos em Limoeiro do Norte-Ceará, foram colhidos na maturidade fisiológica. Os tratamentos utilizados foram: controle, 200 nL.L-1 de 1-MCP, pulverização com cera Fruit wax® e pulverização com Fruit wax® seguida da aplicação de 200 nL.L-1 de 1-MCP. Os frutos foram armazenados por 0, 4, 8, 11, 13 e 15 dias, a 15,4±1,1ºC e 86±7% UR. Utilizou-se o delineamento experimental inteiramente casualizado, em fatorial 4x6, com quatro repetições. A partir do quarto e até o oitavo dia, observou-se intensa atividade metabólica, acompanhada por rápida degradação de amido e aumento da atividade da -galactosidase. Os tratamentos pós-colheita atrasaram ou reduziram a respiração e a produção de etileno. O amaciamento foi mais lento nos frutos tratados, principalmente entre o quarto e o oitavo dias. O tratamento cera+1-MCP reduziu temporariamente a atividade da poligalacturonase e manteve estável a da amilase. Entretanto, a cera foi o tratamento mais eficiente porque preservou a aparência por até treze dias.The effect of postharvest application of 1-methylcylopropene (1-MCP and wax on respiratory behavior and biochemical changes was evaluated regarding the softening of soursop fruit 'Morada', during refrigerated storage. Fruits produced in Limoeiro do Norte, State of Ceara, Brazil, were harvested at the physiological maturity stage. The treatments were: control, 200 nL.L-1 of 1-MCP, Fruit wax® sprayed on fruits, and Fruit wax® sprayed on fruits followed by application of 200 nL.L-1 of 1-MCP. The fruits were stored during 0, 4, 8, 11, 13 and 15 days, at 15.4±1.1ºC and 86±7% RH. A completely randomized experimental design was used, with a 4x6 factorial and four replications. From the

  13. Microstructural, Micro-hardness and Sensitization Evaluation in HAZ of Type 316L Stainless Steel Joint with Narrow Gap Welds

    Energy Technology Data Exchange (ETDEWEB)

    Islam, Faisal Shafiqul; Jang, Changheui [KAIST, Daejeon (Korea, Republic of); Kang, Shi Chull [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2015-10-15

    From Micro-hardness measurement HAZ zone was found approximately 1-1.5 mm in NGW and DL-EPR test confirmed that 316L NGW HAZ was not susceptible to sensitization as DOS <1% according to sensitization criteria based on reference. In nuclear power plants 316L stainless steels are commonly used material for their metallurgical stability, high corrosion resistance, and good creep and ductility properties at elevated temperatures. Welding zone considered as the weakest and failure initiation source of the components. For safety and economy of nuclear power plants accurate and dependable structural integrity assessment of main components like pressure vessels and piping are need as it joined by different welding process. In similar and dissimilar metal weld it has been observed that weld microstructure cause the variation of mechanical properties through the thickness direction. In the Heat Affected Zone (HAZ) relative to the fusion line face a unique thermal experience during welding.

  14. Intensidad de un haz de luz con momento angular orbital entero y no entero en campo lejano

    OpenAIRE

    2014-01-01

    La forma del patrón de intensidad en campo lejano de un haz luminoso con un valor bien definido de momento angular orbital entero y no en - tero es analizada teórica y experimentalmente. Mediante simulaciones numéricas de una onda plana difractada por un holograma en forma de tenedor se calcula para los haces con momento angular orbital entero m el radio promedio del anillo interno del haz en el régimen de Fraunhofer, mientras que para los haces con momento angular orbital no entero M se anal...

  15. Vibrational Softening of a Protein on Ligand Binding

    Energy Technology Data Exchange (ETDEWEB)

    Balog, Erica [Semmelweis University, Budapest, Hungary; Perahia, David [Ecole Normale Superieure de Cachan, Cachan, France; Smith, Jeremy C [ORNL; Merzel, Franci [National Institute of Chemistry, Solvenia

    2011-01-01

    Neutron scattering experiments have demonstrated that binding of the cancer drug methotrexate softens the low-frequency vibrations of its target protein, dihydrofolate reductase (DHFR). Here, this softening is fully reproduced using atomic detail normal-mode analysis. Decomposition of the vibrational density of states demonstrates that the largest contributions arise from structural elements of DHFR critical to stability and function. Mode-projection analysis reveals an increase of the breathing-like character of the affected vibrational modes consistent with the experimentally observed increased adiabatic compressibility of the protein on complexation.

  16. Low-temperature softening in body-centered cubic alloys

    Science.gov (United States)

    Pink, E.; Arsenault, R. J.

    1979-01-01

    In the low-temperature range, bcc alloys exhibit a lower stress-temperature dependence than the pure base metals. This effect often leads to a phenomenon that is called 'alloy softening': at low temperatures, the yield stress of an alloy may be lower than that of the base metal. Various theories are reviewed; the most promising are based either on extrinsic or intrinsic models of low-temperature deformation. Some other aspects of alloy softening are discussed, among them the effects on the ductile-brittle transition temperature.

  17. Estudio del haz de neutrones del reactor RP-10 aplicados a la neutrografía

    OpenAIRE

    Zegarra,Manuel; López, Alcides

    2014-01-01

    Se estudió el haz de neutrones del conducto radial N° 3 del reactor RP-10 que es usado para la obtención de neutrografías, mediante la comparación de registros neutrográficos con y sin el ducto interno, así como la determinación del flujo neutrónico a 2 grupos mediante hojuelas de In a lo largo del conducto exterior, encontrándose la presencia de fotones que crean señales en niveles comparables a los efectos de los neutrones que disminuyen la calidad del análisis. Se obtuvieron valores de al...

  18. Utilization of accident databases and fuzzy sets to estimate frequency of HazMat transport accidents.

    Science.gov (United States)

    Qiao, Yuanhua; Keren, Nir; Mannan, M Sam

    2009-08-15

    Risk assessment and management of transportation of hazardous materials (HazMat) require the estimation of accident frequency. This paper presents a methodology to estimate hazardous materials transportation accident frequency by utilizing publicly available databases and expert knowledge. The estimation process addresses route-dependent and route-independent variables. Negative binomial regression is applied to an analysis of the Department of Public Safety (DPS) accident database to derive basic accident frequency as a function of route-dependent variables, while the effects of route-independent variables are modeled by fuzzy logic. The integrated methodology provides the basis for an overall transportation risk analysis, which can be used later to develop a decision support system.

  19. Comparing Extended System Interactions with Motions in Softened Potentials

    CERN Document Server

    Barnes, Eric I

    2015-01-01

    Using an $N$-body evolution code that does not rely on softened potentials, I have created a suite of interacting binary cluster simulations. The motions of the centers-of-mass of the clusters have been tracked and compared to the trajectories of point masses interacting via one of four different softened potential prescriptions. There is a robust, nearly linear relationship between the impact parameter of the cluster interaction and the point-mass softening length that best approximates the cluster centers-of-mass motion. In an $N$-body simulation that adopts a fixed softening length, such a relationship leads to regimes where two-body effects, like dynamical friction, can be either larger or smaller than the corresponding cluster situation. Further consideration of more specific $N$-body simulations leads to an estimate that roughly 10 per cent of point-mass interactions in an $N$-body simulation will experience two-body effects larger than those for equivalent clusters.

  20. Stress-Softening and Residual Strain Effects in Suture Materials

    Directory of Open Access Journals (Sweden)

    Alex Elías-Zúñiga

    2013-01-01

    Full Text Available This work focuses on the experimental characterization of suture material samples of MonoPlus, Monosyn, polyglycolic acid, polydioxanone 2–0, polydioxanone 4–0, poly(glycolide-co-epsilon-caprolactone, nylon, and polypropylene when subjected to cyclic loading and unloading conditions. It is found that all tested suture materials exhibit stress-softening and residual strain effects related to the microstructural material damage upon deformation from the natural, undistorted state of the virgin suture material. To predict experimental observations, a new constitutive material model that takes into account stress-softening and residual strain effects is developed. The basis of this model is the inclusion of a phenomenological nonmonotonous softening function that depends on the strain intensity between loading and unloading cycles. The theory is illustrated by modifying the non-Gaussian average-stretch, full-network model to capture stress-softening and residual strains by using pseudoelasticity concepts. It is shown that results obtained from theoretical simulations compare well with suture material experimental data.

  1. Cyclic softening and thermally activated deformation of titanium and zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Dickson, J.I.; Handfield, L.; L' Esperance, G. (Ecole Polytechnique, Montreal, Quebec (Canada). Dept. de Genie Metallurgique)

    1983-08-01

    Cyclic softening in commercial purity zirconium and titanium corresponds principally to a decrease in effective stress and to an increase in screw dislocation mobility. This result indicates that the thermally activated deformation of these metals is not controlled by the overcoming of individual interstitial solute atoms by dislocations as usually proposed.

  2. Investigation of the precipitation mechanism in HAZ of super-martensitic stainless steels. Two-pass weld simulation

    Energy Technology Data Exchange (ETDEWEB)

    Ladanova, Elena; Solberg, Jan K. [The Norwegian University of Science and Technology, N-7491 Trondheim (Norway); Rogne, Trond [SINTEF Materials and Chemistry, N-7465 Trondheim (Norway)

    2004-07-01

    Weld simulation is widely used for studying weldability of steels. Mostly, HAZ of one pass welding is simulated, and the produced specimens are mainly used for mechanical testing. Another way of applying weld simulation is to find the temperature history giving a certain microstructure observed in the HAZ of a real multipass weld. In the present work, a two-pass weld simulation was used to investigate the precipitation mechanism of carbides in the HAZ of two super-martensitic stainless steels. Previously, a model for carbide precipitation was suggested. According to this model, a reheating of the HAZ in the martensitic stage is needed to provoke strong carbide formation. In the present work, the peak temperatures of the first and second heating pass and also the temperature of the inter-pass holding were varied together with holding time during the reheat (the second pass). The most favourable heating regime for grain boundary carbide precipitation was found for both investigated steels. In addition, measurements of the chromium content across prior austenite grain boundaries were done for one of the investigated steels. The thin foils were prepared from the specimens where the strongest carbide precipitation was observed. (authors)

  3. REMOVAL OF BERYLLIUM FROM DRINKING WATER BY CHEMICAL COAGULATION AND LIME SOFTENING

    Science.gov (United States)

    The effectiveness of conventional drinking water treatment and lime softening was evaluated for beryllium removal from two drinking water sources. ar test studies were conducted to determine how common coagulants (aluminum sulfate and ferric chloride and lime softening performed ...

  4. Ground reaction curves for circular excavations in non-homogeneous, axisymmetric strain-softening rock masses

    Institute of Scientific and Technical Information of China (English)

    J. González-Cao; F. Varas; F.G. Bastante; L.R. Alejano

    2013-01-01

    Fast methods to solve the unloading problem of a cylindrical cavity or tunnel excavated in elasto-perfectly plastic, elasto-brittle or strain-softening materials under a hydrostatic stress field can be derived based on the self-similarity of the solution. As a consequence, they only apply when the rock mass is homoge-neous and so exclude many cases of practical interest. We describe a robust and fast numerical technique that solves the tunnel unloading problem and estimates the ground reaction curve for a cylindrical cavity excavated in a rock mass with properties depending on the radial coordinate, where the solution is no longer self-similar. The solution is based on a continuation-like approach (associated with the unloading and with the incremental formulation of the elasto-plastic behavior), finite element spatial discretization and a combination of explicit sub-stepping schemes and implicit techniques to integrate the constitutive law, so as to tackle the difficulties associated with both strong strain-softening and elasto-brittle behav-iors. The developed algorithm is used for two practical ground reaction curve computation applications. The first application refers to a tunnel surrounded by an aureole of material damaged by blasting and the second to a tunnel surrounded by a ring-like zone of reinforced (rock-bolted) material.

  5. Effect of temperature on thermal softening of black sweet-bamboo culms (Dendrocalamus asper Backer in linseed oil

    Directory of Open Access Journals (Sweden)

    Banyat Cherdchim

    2004-11-01

    Full Text Available The aim of this research is to study the effect of temperature on thermal softening behavior of black sweet-bamboo culms in linseed oil. Pressing test rig with a length scale and a pointer indicating specimen height was constructed. This apparatus was used to apply a compressive force to bamboo specimen immersed in hot linseed oil in a boiler. Half circular cross-section specimens with thickness of 3 mm and length of 150 mm were dipped into water at room temperature to attain water saturated condition prior to immersing into linseed oil at various temperatures under the load of 20 N. Specimen height, used to calculate the degree of flatness, was measured as a function of time. The values of the final degree of flatness and the rate of degree of flatness were used for the analysis of thermal softening behavior of bamboo in linseed oil. It was found that thermal softening behavior of bamboo culms in linseed oil was divided into two temperature regimes with the glass transition temperature at 115ºC. At low temperature regime, deformation occurred slowly and showed only a single stage of deformation, corresponding to deformation in the glassy state. At high temperature regime, specimens deformed slowly in the first stage followed by a rapid deformation in the second stage, corresponding to deformations in the glassy and rubbery states, respectively. Effect of temperature on the rate of softening was well described by means of the Arrhenius equation with the activation energy ranging from 18 kJ/mole to 32 kJ/mole.

  6. Enhancing international earth science competence in natural hazards through 'geoNatHaz

    Science.gov (United States)

    Giardino, Marco; Clague, John J.

    2010-05-01

    "geoNatHaz" is a Transatlantic Exchange Partnership project (TEP 2009-2012) within the framework of the EU-Canada programme for co-operation in higher education, training, and youth. The project is structured to improve knowledge and skills required to assess and manage natural hazards in mountain regions. It provides student exchanges between European and Canadian universities in order to enhance international competence in natural hazard research. The university consortium is led by Simon Fraser University (Canada) and Università degli studi di Torino (Italy). Partner universities include the University of British Columbia, Queen's University, Università di Bologna, Université de Savoie, and the University of Athens. Université de Lausanne (Switzerland) supports the geoNatHaz advisory board through its bilateral agreements with Canadian partner universities. The geoNatHaz project promotes cross-cultural understanding and internationalization of university natural hazard curricula through common lectures, laboratory exercises, and field activities. Forty graduate students from the seven Canadian and European partner universities will benefit from the project between 2009 and 2012. Some students enrolled in graduate-level earth science and geologic engineering programs spend up to five months at the partner universities, taking courses and participating in research teams under the direction of project scientists. Other students engage in short-term (four-week) exchanges involving training in classic natural hazard case-studies in mountain regions of Canada and Europe. Joint courses are delivered in English, but complementary cultural activities are offered in the languages of the host countries. Supporting organizations offer internships and technical and scientific support. Students benefit from work-study programs with industry partners. Supporting organizations include government departments and agencies (Geological Survey of Canada; CNR-IRPI National

  7. Mechanism of Annealing Softening of Rolled or Forged Tool Steel

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In order to reduce hardness of rolled or forged steels after annealing and improve processability, the diameter and dispersity of carbides were measured by SEM and quantitative metallography. The microstructure of annealed steel was analyzed by TEM. The effects of the factors such as solute atoms, carbides, grain boundary and interphase boundary were studied. The mechanism of annealing softening of steels was analyzed on the examples of steels H13, S5, S7, X45CrNiMo4, which are treated with new technology. The results showed that the softening of H13, S7, S5 is easier obtained by isothermal or slow cooling annealing from slightly below A1, but hardness of X45CrNiMo4 after annealing is reduced effectively by obtaining coarse lamellar pearlite. Economic results can be obtained from good processability.

  8. Electric field-induced softening of alkali silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    McLaren, C.; Heffner, W.; Jain, H. [Department of Materials Science and Engineering, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Tessarollo, R.; Raj, R. [Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309 (United States)

    2015-11-02

    Motivated by the advantages of two-electrode flash sintering over normal sintering, we have investigated the effect of an external electric field on the viscosity of glass. The results show remarkable electric field-induced softening (EFIS), as application of DC field significantly lowers the softening temperature of glass. To establish the origin of EFIS, the effect is compared for single vs. mixed-alkali silicate glasses with fixed mole percentage of the alkali ions such that the mobility of alkali ions is greatly reduced while the basic network structure does not change much. The sodium silicate and lithium-sodium mixed alkali silicate glasses were tested mechanically in situ under compression in external electric field ranging from 0 to 250 V/cm in specially designed equipment. A comparison of data for different compositions indicates a complex mechanical response, which is observed as field-induced viscous flow due to a combination of Joule heating, electrolysis and dielectric breakdown.

  9. Modification of Textile Materials' Surface Properties Using Chemical Softener

    Directory of Open Access Journals (Sweden)

    Jurgita KOŽENIAUSKIENĖ

    2011-03-01

    Full Text Available In the present study the effect of technological treatment involving the processes of washing or washing and softening with chemical cationic softener "Surcase" produced in Great Britain on the surface properties of cellulosic textile materials manufactured from cotton, bamboo and viscose spun yarns was investigated. The changes in textile materials surface properties were evaluated using KTU-Griff-Tester device and FEI Quanta 200 FEG scanning electron microscope (SEM. It was observed that the worst hand properties and the higher surface roughness are observed of cotton materials if compared with those of bamboo and viscose materials. Also, it was shown that depending on the material structure the handle parameters of knitted materials are the better than the ones of woven fabrics.http://dx.doi.org/10.5755/j01.ms.17.1.249

  10. Solving the standard model problems in softened gravity

    Science.gov (United States)

    Salvio, Alberto

    2016-11-01

    The Higgs naturalness problem is solved if the growth of Einstein's gravitational interaction is softened at an energy ≲1 011 GeV (softened gravity). We work here within an explicit realization where the Einstein-Hilbert Lagrangian is extended to include terms quadratic in the curvature and a nonminimal coupling with the Higgs. We show that this solution is preserved by adding three right-handed neutrinos with masses below the electroweak scale, accounting for neutrino oscillations, dark matter and the baryon asymmetry. The smallness of the right-handed neutrino masses (compared to the Planck scale) and the QCD θ -term are also shown to be natural. We prove that a possible gravitational source of C P violation cannot spoil the model, thanks to the presence of right-handed neutrinos. Inflation is approximately described by the Starobinsky model in this context and can occur even if we live in a metastable vacuum.

  11. Electric field-induced softening of alkali silicate glasses

    Science.gov (United States)

    McLaren, C.; Heffner, W.; Tessarollo, R.; Raj, R.; Jain, H.

    2015-11-01

    Motivated by the advantages of two-electrode flash sintering over normal sintering, we have investigated the effect of an external electric field on the viscosity of glass. The results show remarkable electric field-induced softening (EFIS), as application of DC field significantly lowers the softening temperature of glass. To establish the origin of EFIS, the effect is compared for single vs. mixed-alkali silicate glasses with fixed mole percentage of the alkali ions such that the mobility of alkali ions is greatly reduced while the basic network structure does not change much. The sodium silicate and lithium-sodium mixed alkali silicate glasses were tested mechanically in situ under compression in external electric field ranging from 0 to 250 V/cm in specially designed equipment. A comparison of data for different compositions indicates a complex mechanical response, which is observed as field-induced viscous flow due to a combination of Joule heating, electrolysis and dielectric breakdown.

  12. Nonlinear softening as a predictive precursor to climate tipping

    CERN Document Server

    Sieber, Jan

    2011-01-01

    Approaching a dangerous bifurcation, from which a dynamical system such as the Earth's climate will jump (tip) to a different state, the current stable state lies within a shrinking basin of attraction. Persistence of the state becomes increasingly precarious in the presence of noisy disturbances. We consider an underlying potential, as defined theoretically for a saddle-node fold and (via averaging) for a Hopf bifurcation. Close to a stable state, this potential has a parabolic form; but approaching a jump it becomes increasingly dominated by softening nonlinearities. If we have already detected a decrease in the linear decay rate, nonlinear information allows us to estimate the propensity for early tipping due to noise. If there is no discernable trend in the linear analysis, nonlinear softening is even more important in showing the proximity to tipping. After extensive normal form calibration studies, we apply our technique to two geological time series from paleo-climate tipping events. For the ending of ...

  13. Solving the Standard Model Problems in Softened Gravity

    CERN Document Server

    Salvio, Alberto

    2016-11-16

    The Higgs naturalness problem is solved if the growth of Einstein's gravitational interaction is softened at an energy $ \\lesssim 10^{11}\\,$GeV (softened gravity). We work here within an explicit realization where the Einstein-Hilbert Lagrangian is extended to include terms quadratic in the curvature and a non-minimal coupling with the Higgs. We show that this solution is preserved by adding three right-handed neutrinos with masses below the electroweak scale, accounting for neutrino oscillations, dark matter and the baryon asymmetry. The smallness of the right-handed neutrino masses (compared to the Planck scale) and the QCD $\\theta$-term are also shown to be natural. We prove that a possible gravitational source of CP violation cannot spoil the model, thanks to the presence of right-handed neutrinos. Starobinsky inflation can occur in this context, even if we live in a metastable vacuum.

  14. Potassium softens vascular endothelium and increases nitric oxide release

    OpenAIRE

    2009-01-01

    In the presence of aldosterone, plasma sodium in the high physiological range stiffens endothelial cells and reduces the release of nitric oxide. We now demonstrate effects of extracellular potassium on stiffness of individual cultured bovine aortic endothelial cells by using the tip of an atomic force microscope as a mechanical nanosensor. An acute increase of potassium in the physiological range swells and softens the endothelial cell and increases the release of nitric oxide. A high physio...

  15. Phonon softening and dispersion in EuTiO3

    Science.gov (United States)

    Ellis, David S.; Uchiyama, Hiroshi; Tsutsui, Satoshi; Sugimoto, Kunihisa; Kato, Kenichi; Ishikawa, Daisuke; Baron, Alfred Q. R.

    2012-12-01

    We measured phonon dispersion in single-crystal EuTiO3 using inelastic x-ray scattering. A structural transition to an antiferrodistortive phase was found at a critical temperature T0=287±1 K using powder and single-crystal x-ray diffraction. Clear softening of the zone boundary R-point q=(0.50.50.5) acoustic phonon shows this to be a displacive transition. The mode energy plotted against reduced temperature could be seen to nearly overlap that of SrTiO3, suggesting a universal scaling relation. Phonon dispersion was measured along Γ-X (000)→(0.500). Mode eigenvectors were obtained from a shell model consistent with the q dependence of intensity and energy, which also showed that the dispersion is nominally the same as in SrTiO3 at room temperature, but corrected for mass. The lowest-energy optical mode, determined to be of Slater character, softens approximately linearly with temperature until the 70-100 K range where the softening stops, and at low temperature, the mode disperses linearly near the zone center.

  16. Precipitation softening: a pretreatment process for seawater desalination.

    Science.gov (United States)

    Ayoub, George M; Zayyat, Ramez M; Al-Hindi, Mahmoud

    2014-02-01

    Reduction of membrane fouling in reverse osmosis systems and elimination of scaling of heat transfer surfaces in thermal plants are a major challenge in the desalination of seawater. Precipitation softening has the potential of eliminating the major fouling and scaling species in seawater desalination plants, thus allowing thermal plants to operate at higher top brine temperatures and membrane plants to operate at a reduced risk of fouling, leading to lower desalinated water costs. This work evaluated the use of precipitation softening as a pretreatment step for seawater desalination. The effectiveness of the process in removing several scale-inducing materials such as calcium, magnesium, silica, and boron was investigated under variable conditions of temperature and pH. The treatment process was also applied to seawater spiked with other known fouling species such as iron and bacteria to determine the efficiency of removal. The results of this work show that precipitation softening at a pH of 11 leads to complete elimination of calcium, silica, and bacteria; to very high removal efficiencies of magnesium and iron (99.6 and 99.2 %, respectively); and to a reasonably good removal efficiency of boron (61 %).

  17. Pemanfaatan ter sebagai softener dalam pembuatan karet riklim

    Directory of Open Access Journals (Sweden)

    Arum Yuniari

    2006-07-01

    Full Text Available The aims of this research was to study the effect of Coal Tar as softener for reclaim rubber production from waste of rubber of tyre rethreading as input materials was scrap rubber. Coal Tar as softener was used with variation; 2,5; 5; 7,5; 10; 12,5 and 15% respectively from total scrap rubber. Reclaimed rubber was made at temperature 1200C for 1 hour in autoclave and than it was subsequently ground with two rolls mills. The characteristics of the reclaimed rubber was tested for the vulcanization and physical properties. The results showed that Coal Tar could be utilized as softener for reclaimed rubber. Reclaimed rubber production containing Coal Tar 15% would give good vulcanization and physical properties. The vulcanization 1062 seconds, maximum torque 39,08 kgf-cm, minimum torque 4,71 kgf-cm. Good physical properties : tensile strength 80,74 kg/cm2 elongation at break 444,62%, hardness 49 shore A, tear strength 40,39 kg/cm, density 1,15 g/cm3, abrasion resistance 1,87 mm3/kgm, and no crack detected on the flex cracking test of 150 kcs

  18. Microstructural Evolution and Dynamic Softening Mechanisms of Al-Zn-Mg-Cu Alloy during Hot Compressive Deformation

    Directory of Open Access Journals (Sweden)

    Cangji Shi

    2014-01-01

    Full Text Available The hot deformation behavior and microstructural evolution of an Al-Zn-Mg-Cu (7150 alloy was studied during hot compression at various temperatures (300 to 450 °C and strain rates (0.001 to 10 s−1. A decline ratio map of flow stresses was proposed and divided into five deformation domains, in which the flow stress behavior was correlated with different microstructures and dynamic softening mechanisms. The results reveal that the dynamic recovery is the sole softening mechanism at temperatures of 300 to 400 °C with various strain rates and at temperatures of 400 to 450 °C with strain rates between 1 and 10 s−1. The level of dynamic recovery increases with increasing temperature and with decreasing strain rate. At the high deformation temperature of 450 °C with strain rates of 0.001 to 0.1 s−1, a partially recrystallized microstructure was observed, and the dynamic recrystallization (DRX provided an alternative softening mechanism. Two kinds of DRX might operate at the high temperature, in which discontinuous dynamic recrystallization was involved at higher strain rates and continuous dynamic recrystallization was implied at lower strain rates.

  19. Controlling the Heat Affected Zone(HAZ) in HF Pipe and Tube Welding%高频焊管焊接热影响区(HAZ)的控制

    Institute of Scientific and Technical Information of China (English)

    汪翰云; 李超; 罗刚

    2012-01-01

    In this article.it found that the HAZ performance of high frequency longitudinal welded pipe is an important factor affecting welding quality.There are many influence factors,how to accurately adjust these factors, according to welded pipe products,to obtain perfect HAZ performance is an important research topic for a long time.lt introduced a kind of open-loop control HAZ technology, which combines experiential knowledge with theoretical calculation, make high frequency welded pipe units operate canonicaUy.let operator know units running state well,and complete setting parameters to ensure welded pipe units run successfully.%研究发现,高频直缝焊接钢管的焊接热影响区(HAZ)性能是影响焊接质量的重要因素.影响HAZ的因素有很多,如何根据所生产的焊管产品来准确调整这些影响参数,从而获得良好的HAZ性能是人们长期以来研究的重要课题.介绍了一种开环控制的焊接HAZ控制技术,将经验知识与理论计算相结合,规范了高频焊管机组运行,使操作者能够更准确地了解机组的运行状态,用较短的时间完成焊管机组成功运行的参数设置.

  20. Effect of strain hardening and strain softening on welding distortion and residual stress of A7N01-T4 aluminum alloy by simulation analysis

    Institute of Scientific and Technical Information of China (English)

    YAN De-jun; LIU Xue-song; LI Jun; YANG Jian-guo; FANG Hong-yuan

    2010-01-01

    The effect of strain hardening and strain softening behavior of flow stress changing with temperature on welding residual stress,plastic strain and welding distortion of A7N01-T4 aluminum alloy was studied by finite simulation method.The simulation results show that the weld seam undergoes strain hardening in the temperature range of 180-250℃,however,it exhibits strain softening at temperature above 250℃ during welding heating and cooling process.As a result,the strain hardening and strain softening effects counteract each other,introducing slightly influence on the welding residual stress,residual plastic strain and distortion.The welding longitudinal residual stress was determined by ultrasonic stress measurement method for the flat plates of A7N01-T4 aluminum alloy.The simulation results are well accordant with test ones.

  1. Structural transition and softening in Al–Fe intermetallic compounds induced by high energy ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Basariya, M. Raviathul, E-mail: ravia80@gmail.com [CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India); Department of Metallurgical Engineering, Indian Institute of Technology (BHU), Varanasi 221005 (India); Roy, Rajat K.; Pramanick, A.K.; Srivastava, V.C. [CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India); Mukhopadhyay, N.K. [Department of Metallurgical Engineering, Indian Institute of Technology (BHU), Varanasi 221005 (India)

    2015-06-25

    In the present investigation, powders of as-cast ingots of Al–25 at%Fe and Al–34.5 at%Fe alloys close to Al{sub 3}Fe and Al{sub 2}Fe intermetallic phases are subjected to high energy ball milling to understand the possibility of formation of amorphous and/or nanocrystalline phases or any other metastable phases. The development of microstructure, evolution of various metastable phases and their stability are investigated by x-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. Mechanical milling of the alloys, up to 50 h, was carried out in high energy planetary ball mill. It resulted in phase transformation from monoclinic and triclinic structures of Al{sub 3}Fe and Al{sub 2}Fe, respectively, to orthorhombic structure pertaining to Al{sub 5}Fe{sub 2} phase and structural transformation from crystalline to amorphous phase. Hardness measurements revealed a transition from hardening to softening behavior in these mechanically milled alloys undergoing prolonged milling. The softening effect in the milled powders, having a composite structure involving nanocrystalline and amorphous phases, is attributed to the competing phenomenon of grain size reduction and amorphous phase formation with increasing milling time.

  2. Metallization and softening of B{sub 6}O at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuehui [Institute of Physics and Chemistry, HNUST, Qinhuangdao, Hebei 066600 (China); Wang, Yachun; Yao, Tiankai; Li, Hui; Wu, Lailei; Yang, Meng [Key Laboratory of Metastable Materials Science and Technology, College of Material Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Zhang, Jingwu, E-mail: ziw@ysu.edu.cn [Key Laboratory of Metastable Materials Science and Technology, College of Material Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Gou, Huiyang, E-mail: huiyang.gou@gmail.com [Key Laboratory of Metastable Materials Science and Technology, College of Material Science and Engineering, Yanshan University, Qinhuangdao 066004 (China)

    2014-07-05

    Highlights: • Structural searching identified a high-pressure phase for B{sub 6}O with monoclinic Cc structure. • Cc structure B{sub 6}O is mechanically and dynamically stable. • Cc phase characterizes in pentagonal pyramids and zig-zag O–B1–O chains. • Cc phase shows metallization and softened hardness as compared to zero-pressure structure. - Abstract: Structural stability, elastic and electronic properties of boron suboxide, B{sub 6}O, up to 300 GPa were investigated by first-principles calculations. Structural searching and enthalpy differences calculations identify a high-pressure phase for B{sub 6}O with monoclinic Cc structure (denoted as β-B{sub 6}O), which is energetically preferable to the known R-3 m-type phase above 245 GPa. β-B{sub 6}O phase forms a three-dimensional covalent network mainly composed of pentagonal pyramids and zig-zag O–B1–O chains extended along c-direction. β-B{sub 6}O phase is found to be stable examined by the calculated elastic constants and phonon dispersion and exhibits metallic behavior and greater elastic and hardness anisotropy, totally different from the semiconducting character and relative isotropy of ground state structure. Moreover, β-B{sub 6}O is predicted to soften significantly with a Vicker’s hardness of about 20.7 GPa.

  3. Mechanism of intergranular stress corrosion cracking in HAZ for super-martensitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, Yukio; Kimura, Mitsuo [Tubular Products and Casting Research Dept., JFE Steel Corporation, 1-1, Kawasaki-cho, Handa (Japan); Nakamichi, Haruo; Sato, Kaoru [Analysis and Characterization Research Dept., JFE Steel Corporation, 1-1, Minamiwatarida-cho, Kawasaki-ku, Kawasaki (Japan); Itakura, Noritsugu [Products Service and Development Dept., Chita Works, JFE Steel Corporation. 1-1, Kawasaki-cho, Handa (Japan); Masamura, Katsumi [Tubular Products Business Planning Dept., JFE Steel Corporation, 2-2-3, Uchisaiwai-sho, Chiyoda-ku, Tokyo (Japan)

    2004-07-01

    Mechanism of intergranular stress corrosion cracking (IGSCC) for heat affected zone (HAZ) of super-martensitic stainless steel was studied using two types of the steel. One was a lean grade, which was Mo free and low Ni, and the other was a high grade, which was Mo added and high Ni. Specimens received heat treatments simulating welding thermal cycles were applied to SCC tests. Cracks were observed in some specimens after U-bend SCC test under low pH environments. Thermal cycle conditions with sensitization were verified from the results. No crack was observed in the specimen with the thermal cycle simulating post welding heat treatment (PWHT) after sensitizing conditions. Therefore, PWHT was clarified to be effective to prevent the cracking. Cr carbides were observed along prior austenite grain boundary intermittently, and Cr depleted zone was confirmed on the grain boundary adjacent to carbides that precipitated on the grain boundary. It is, therefore, concluded that the cracking results from Cr depletion on prior austenite grain boundary accompanied by precipitation of Cr carbides under specific welding conditions. (authors)

  4. Comparison of resistance to corrosion on haz of a ferritic stainless steel by different surface finishings

    Directory of Open Access Journals (Sweden)

    Juvenilson Costa Damascena

    2015-10-01

    Full Text Available Certain techniques, comprising machining and GTAW dressing, have been used in the weld bead edge (region of the welded joint between the weld metal and the base metal to increase the fillet radius of the region by reducing the stress concentrator factor, decreasing roughness, and increasing the life of weldings. Moreover, TIG Dressing may also provide a smooth change in the radius of the curvature and change the average grain size and promote a microstructural variation through the reflow of this region. Current study analyzes the effect of surface finish of the Heat Affected Zone (HAZ on resistance to corrosion of welded joints of simple deposition under plate by using machining techniques with sandpaper of different particle sizes and GTAW Dressing, comparing the effect of the two techniques in the resistance to corrosion in environments with chloride ions. ACE P410D ferritic stainless steel was employed as base metal and austenitic wire 308L for welding. Results showed that the condition sweetened with GTAW Dressing with pure argon at current 100A generated the lowest mass loss among the conditions under analysis.

  5. The Segregation and Liquation Crackings in the HAZ of Multipass Laser-Welded Joints for Nuclear Power Plants

    Science.gov (United States)

    Li, Gang; Lu, Xiaofeng; Zhu, Xiaolei; Huang, Jian; Liu, Luwei; Wu, Yixiong

    2017-08-01

    The segregation and liquation crackings in the heat-affected zone (HAZ) beside Inconel 52M overlays of multipass laser-welded joints are investigated for nuclear power plants. The results indicate that Nb-rich precipitates are distributed in chains and some aggregate together as coarse particles in the local regions at the interface. With increasing heat input, the transition width becomes widened and the fraction of the precipitates at the interface significantly increases. Closely associated to Nb segregation, liquation crackings occur along columnar dendrites in the HAZ beside Inconel 52M overlays. Due to no deformation coordination of the columnar dendrites with Nb-rich segregates in Inconel 52M overlays, liquation crackings occur in thermal cycle of multipass laser welding. The enrichment of Nb element in the interdendritic regions increases favorable factors of liquation crackings at grain boundaries.

  6. The effect of grain boundary segregation of boron in cast alloy 718 on HAZ microfissuring -- a SIMS analysis

    Energy Technology Data Exchange (ETDEWEB)

    Huang, X.; Chaturvedi, M.C. [Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Mechanical and Industrial Engineering; Richards, N.L. [Bristol Aerospace Ltd., Winnipeg, Manitoba (Canada); Jackman, J. [CANMET, Ottawa, Ontario (Canada)

    1997-08-01

    Secondary ion mass spectroscopy (SIMS) has been used to examine grain boundary segregation in cast alloy 718. The relationship between the boron segregation and the microfissuring tendency in heat affected zones (HAZ) around electron beam welds is discussed in this study. It is concluded that two types of segregation, namely equilibrium and non-equilibrium segregation, occurred during the homogenization heat treatment of the base material. Water quenching after the homogenization treatment inhibited non-equilibrium segregation of boron and other trace elements owing to insufficient time for diffusion of solute-vacancy complexes to occur. Intermediate cooling rates such as air cooling enhanced both non-equilibrium and equilibrium segregation, since equilibrium segregation occurred during holding at the heat treatment temperature. The value of net segregation produced by a combination of equilibrium segregation and non-equilibrium segregation varied with temperature in a U-shape. The nature of the grain boundary in the cast alloy was examined by using an electron backscattered diffraction (EBSD) technique and it was found that 93% of the grain boundaries were of the random type ({Sigma} > 49). The weldability of this alloy was found to be closely related to the grain boundary segregation of boron, i.e., the variation of HAZ total crack length (TCL) with pre-welding heat treatment temperatures has a trend similar to that of boron segregation with temperature after air cooling. Mechanisms for the effect of boron on HAZ microfissuring have been proposed.

  7. Intensidad de un haz de luz con momento angular orbital entero y no entero en campo lejano

    Directory of Open Access Journals (Sweden)

    Cristian Hernando Acevedo Cáceres

    2014-01-01

    Full Text Available La forma del patrón de intensidad en campo lejano de un haz luminoso con un valor bien definido de momento angular orbital entero y no en - tero es analizada teórica y experimentalmente. Mediante simulaciones numéricas de una onda plana difractada por un holograma en forma de tenedor se calcula para los haces con momento angular orbital entero m el radio promedio del anillo interno del haz en el régimen de Fraunhofer, mientras que para los haces con momento angular orbital no entero M se analiza la rotación de la distribución de intensidad en el campo lejano difractado provocada por el giro de la discontinuidad en el holograma en forma de tenedor. Los resultados experimentales de la forma del patrón de difracción en campo lejano de un haz con momento angular orbital entero y no entero producto de hacer incidir una onda electromagnética plana sobre un holograma computarizado en forma de tenedor desplegado sobre un modulador espacial de luz son presentados para corroborar los resultados teóricos.

  8. Effect of softening function on the cohesive crack fracture parameters of concrete CT specimen

    Indian Academy of Sciences (India)

    Shailendra Kumar; S V Barai

    2009-12-01

    The paper presents numerical study on the fracture parameters of concrete compact tension test specimens of different sizes using cohesive crack model. As softening function is the main ingredient of the cohesive crack model, seven numbers of widely used softening functions are incorporated in the model based on enhanced algorithm. It is found that the difference between the highest and the lowest peak loads obtained using various softening functions (except linear) is less than about 9%. The peak load predicted by the linear softening curve is about 16% larger than that of mean peak load predicted by other softening functions. The cohesive crack model with linear softening yields the fracture process zones lower by approximately 30–50% than those obtained by using the other softening relations for specimen size range 200–600 mm. The numerical results are further compared with a reference test result available in the literature. It is observed that some of softening relations (except linear) predict the experimentally obtained peak load up to 6% of accuracy whereas the linear softening curve overestimates it by about 30%. The numerically gained softening branch of load-displacement curves compare well with the experimental observation.

  9. Softening the Complexity of Entropic Motion on Curved Statistical Manifolds

    CERN Document Server

    Cafaro, Carlo; Lupo, Cosmo; Mancini, Stefano

    2011-01-01

    We study the information geometry and the entropic dynamics of a 3D Gaussian statistical model. We then compare our analysis to that of a 2D Gaussian statistical model obtained from the higher-dimensional model via introduction of an additional information constraint that resembles the quantum mechanical canonical minimum uncertainty relation. We show that the chaoticity (temporal complexity) of the 2D Gaussian statistical model, quantified by means of the Information Geometric Entropy (IGE) and the Jacobi vector field intensity, is softened with respect to the chaoticity of the 3D Gaussian statistical model.

  10. Development of Tensile Softening Model for Plain Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.K.; Song, Y.C. [Korea Electric Power Research Institute, Taejon (Korea)

    2002-07-01

    Large-scale direct tensile softenng tests using plate concrete specimens(4000, 5000psi) with notch were performed under uniaxial stress. There were presented the basic physical properties and the complete load-CMOD(Crack Mouth Opening Displacement) curves for them And them the fracture energy was evaluated using the complete load-CMOD curves respectively, and there was presents optimal tensile softening model which is modified by a little revision of an existing one. Therefore, here provided the real verification data through the tests for developing other nonlinear concrete finite element models. (author). 32 refs., 38 figs., 4 tabs.

  11. Phonon Softening and Dispersion in EuTiO3

    OpenAIRE

    Ellis, David S.; UCHIYAMA, Hiroshi; Tsutsui, Satoshi; Sugimoto, Kunihisa; Kato, Kenichi; Ishikawa, Daisuke; Baron, Alfred Q. R.

    2012-01-01

    We measured phonon dispersion in single crystal EuTiO$_3$ using inelastic x-ray scattering. A structural transition to an antiferrodistortive phase was found at a critical temperature $T_0$=287$\\pm$1 K using powder and single-crystal x-ray diffraction. Clear softening of the zone boundary \\emph{R}-point \\textbf{q}=(0.5 0.5 0.5) acoustic phonon shows this to be a displacive transition. The mode energy plotted against reduced temperature could be seen to nearly overlap that of $\\rm SrTiO_3$, su...

  12. PHONON SOFTENING IN INTERMEDIATE VALENT SmB6

    OpenAIRE

    Mörke, I.; Wachter, P.

    1981-01-01

    We have measured the Raman spectrum of a SmB6 single crystal and compared it to LaB6 and EuB6. Beside the three high energy Raman active phonons we found additional excitations in these compounds. Most prominent is a peak at 172 cm-1 for SmB6, 214 cm-1 for LaB6 and 220 cm-1 for EuB6. The spectra are analysed in terms of defect induced phonon scattering. The softening of the line in intermediate valent (IV) SmB6 is explained in analogy with the phonon anomalies found in other IV compounds.

  13. Life cycle assessment of central softening of very hard drinking water

    DEFF Research Database (Denmark)

    Godskesen, Berit; Hauschild, Michael Zwicky; Rygaard, Martin;

    2012-01-01

    Many consumers prefer softened water due to convenience issues such as avoidance of removing limescale deposits from household appliances and surfaces, and to reduce consumption of cleaning agents and laundry detergents leading to lower household expenses. Even though central softening of drinking...... water from the initial hardness of the region of study (Copenhagen, Denmark) which is 362 mg/L as CaCO(3) to a final hardness as CaCO(3) of 254 (a softening depth of 108) mg/L or 145 (a softening depth of 217) mg/L. Our study showed that the consumer preference can be met together with reducing...... Life Cycle Assessment (LCA) to quantify the environmental impacts of central softening of drinking water considering both the negative effects at the waterworks and the positive effects imposed by the changed water quality in the households. The LCA modeling considered central softening of drinking...

  14. Large-Strain Softening of Aluminum in Shear at Elevated Temperature: Influence of Dislocation Climb

    Science.gov (United States)

    Kassner, M. E.; Campbell, C. S.; Ermagan, R.

    2017-09-01

    This communication complements an earlier publication in this journal by the authors describing the basis for large-strain softening in aluminum under pure shear at elevated temperatures. Earlier work by the authors and the materials community only considered changes in the dislocation glide stress with the evolving texture as an explanation for the softening. New analysis finds that changes in the dislocation climb stress with texture development can explain the softening trends.

  15. Effect of potential remineralizing agents on acid softened enamel.

    Science.gov (United States)

    Turssi, Cecilia P; Maeda, Fernando A; Messias, Danielle C F; Neto, Francisco C Rehder; Serra, Mônica C; Galafassi, Daniel

    2011-06-01

    To assess whether pastes containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and calcium sodium phosphosilicate (CSP) protect acid softened enamel against further erosive episodes. Enamel slabs of bovine teeth with preformed erosion-like lesions were randomly assigned to five treatment groups (n = 15): A) CPP-ACP (MI Paste, GC America); B) CPP-ACP+Fluoride (CPP-ACP+F, MI Plus Paste, GC America); C) CSP (Tooth Revitalizing Paste, Oravive); D) fluoridated dentifrice (FD, Sensodyne Cool Gel, GSK); E) control (CO, unexposed to any product). Paste treatments (1:3 slurry in deionized water or undiluted product in the case of the CPP-ACP formulae) were performed between five cycles of alternating erosive challenge (0.3% citric acid, pH = 3.2) and remineralization in artificial saliva. Specimens were analyzed by Knoop surface microhardness (SMH). ANOVA indicated a significant (P< 0.0001) difference among the SMH values attained by acid softened enamel following the exposure to the pastes interspersed with erosion-remineralization cycles. Tukey's test ascertained that SMH values observed for the CPP-ACP+F and CSP groups did not differ from that of FD group, which were significantly higher than that found for the CO group. Specimens treated with CPP-ACP did not differ from any of the other groups.

  16. Internal friction and elastic softening in polycrystalline Nb3Sn

    Science.gov (United States)

    Bussière, J. F.; Faucher, B.; Snead, C. L., Jr.; Welch, D. O.

    1981-10-01

    The vibrating-reed technique was used to measure internal friction and Young's modulus of polycrystalline Nb3Sn in the form of composite Nb-Nb3Sn tapes from 6 to 300 K. In tapes with only small residual strain in the A 15 layers, a dramatic increase in internal friction with decreasing temperature is observed with an abrupt onset at ~48 K. The internal friction Q-1 between 6 and 48 K is believed to be associated with stress-induced motion of martensitic-domain walls. In this temperature range, Q-1 is approximately proportional to the square of the tetragonal strain of the martensitic phase; Q-1~(ca-1)2. With residual compressive strains of ~0.2%, the internal friction associated with domain-wall motion is considerably reduced. This is attributed to a biasing of domain-wall orientation with residual stress, which reduces wall motion induced by the (much smaller) applied stress. The transformation temperature, however, is unchanged (within +/- 1 K) by residual strains of up to 0.2%. Young's modulus exhibits substantial softening on cooling from 300 to 6 K. This softening is substantially reduced in the presence of small residual compressive strains, indicating a highly nonlinear stress-strain relationship as previously reported for V 3Si.

  17. Alloy hardening and softening in binary molybdenum alloys as related to electron concentration

    Science.gov (United States)

    Stephens, J. R.; Witzke, W. R.

    1972-01-01

    An investigation was conducted to determine the effects of alloy additions of hafnium, tantalum, tungsten, rhenium, osmium, iridium, and platinum on hardness of molybdenum. Special emphasis was placed on alloy softening in these binary molybdenum alloys. Results showed that alloy softening was produced by those elements having an excess of s+d electrons compared to molybdenum, while those elements having an equal number or fewer s+d electrons that molybdenum failed to produce alloy softening. Alloy softening and alloy hardening can be correlated with the difference in number of s+d electrons of the solute element and molybdenum.

  18. One- and Two-Dimensional Maximum Softening Indicators for Reinforced Concrete Structures under Seismic Excitation

    DEFF Research Database (Denmark)

    Nielsen, Søren R. K.; Köyüoglu, H. U.; Cakmak, A. S.

    The maximum softening concept is based on the variation of the vibrational periods of a structure during a seismic event. Maximum softening damage indicators, which measure the maximum relative stiffness reduction caused by stiffness and strength deterioration of the actual structure, are calcula......The maximum softening concept is based on the variation of the vibrational periods of a structure during a seismic event. Maximum softening damage indicators, which measure the maximum relative stiffness reduction caused by stiffness and strength deterioration of the actual structure...

  19. The Use of Haz-Flote to Efficiently Remove Mercury from Contaminated Materials

    Energy Technology Data Exchange (ETDEWEB)

    Terry Brown

    2009-03-03

    There are thousands of known contaminated sites in the United Stated, including Superfund sites (1500 to 2100 sites), RCRA corrective action sites (1500 to 3500 sites), underground storage tanks (295,000 sites), U.S. Department of Defense sites (7300 sites), U.S. Department of Energy sites (4,000 sites), mining refuse piles, and numerous other hazardous metals and organic contamination sites. Only a small percentage of these sites has been cleaned up. The development of innovative technologies to handle the various clean-up problems on a national and international scale is commonplace. Many innovative technologies have been developed that can be used to effectively remediate contaminated materials. Unfortunately, many of these technologies are only effective for materials coarser than approximately 200 mesh. In addition, these technologies usually require considerable investment in equipment, and the clean-up costs of soil material are relatively high - in excess of $100 to $500 per yd{sup 3}. These costs result from the elaborate nature of the processes, the costs for power, and the chemical cost. The fine materials are disposed of or treated at considerable costs. As a result, the costs often associated with amelioration of contaminated sites are high. Western Research institute is in the process of developing an innovative soil washing technology that addresses the removal of contaminants from the fine size-fraction materials located at many of the contaminated sites. This technology has numerous advantages over the other ex-situ soil washing techniques. It requires a low capital investment, low operating costs and results in high levels of re-emplacement of the cleaned material on site. The process has the capability to clean the fine fraction (<200 mesh) of the soil resulting in a replacement of 95+% of the material back on-side, reducing the costs of disposal. The Haz-Flote{trademark} technology would expand the application of soil washing technology to heavy

  20. Characterization of HAZ of API X70 Microalloyed Steel Welded by Cold-Wire Tandem Submerged Arc Welding

    Science.gov (United States)

    Mohammadijoo, Mohsen; Kenny, Stephen; Collins, Laurie; Henein, Hani; Ivey, Douglas G.

    2017-03-01

    High-strength low-carbon microalloyed steels may be adversely affected by the high-heat input and thermal cycle that they experience during tandem submerged arc welding. The heat-affected zone (HAZ), particularly the coarse-grained heat-affected zone (CGHAZ), i.e., the region adjacent to the fusion line, has been known to show lower fracture toughness compared with the rest of the steel. The deterioration in toughness of the CGHAZ is attributed to the formation of martensite-austenite (M-A) constituents, local brittle zones, and large prior austenite grains (PAG). In the present work, the influence of the addition of a cold wire at various wire feed rates in cold-wire tandem submerged arc welding, a recently developed welding process for pipeline manufacturing, on the microstructure and mechanical properties of the HAZ of a microalloyed steel has been studied. The cold wire moderates the heat input of welding by consuming the heat of the trail electrode. Macrostructural analysis showed a decrease in the CGHAZ size by addition of a cold wire. Microstructural evaluation, using both tint etching optical microscopy and scanning electron microscopy, indicated the formation of finer PAGs and less fraction of M-A constituents with refined morphology within the CGHAZ when the cold wire was fed at 25.4 cm/min. This resulted in an improvement in the HAZ impact fracture toughness. These improvements are attributed to lower actual heat introduced to the weldment and lower peak temperature in the CGHAZ by cold-wire addition. However, a faster feed rate of the cold wire at 76.2 cm/min adversely affected the toughness due to the formation of slender M-A constituents caused by the relatively faster cooling rate in the CGHAZ.

  1. Searching for Terrain Softening near Mercury's North Pole

    Science.gov (United States)

    Cobian, P. S.; Vilas, F.; Lederer, S. M.; Barlow, N. G.

    2004-01-01

    In 1999, following the initial discovery of radar bright craters near both poles of Mercury measured the depth-todiameter (d/D) ratios of 170 impact craters in Mariner 10 images covering four different regions on Mercury s surface. Rapid softening of crater structure, indicated by lower d/D ratios, could indicate the possibility of subsurface water ice in Mercury's terrain originating from an internal source in the planet. Their study included 3 specific radar bright craters suggested to contain ice. They concluded that no terrain softening was apparent, and a rapidly emplaced exogenic water source was the most likely source for the proposed ice in these craters. Recent radar observations of the Mercurian North pole have pinpointed many additional radar bright areas with a resolution 10x better than previous radar measurements, and which correlate with craters imaged by Mariner 10. These craters are correlated with regions that are permanently shaded from direct sunlight, and are consistent with observations of clean water ice. We have expanded the initial study by Barlow et al. to include d/D measurements of 12 craters newly identified as radar bright at latitudes poleward of +80o. The radar reflectivity resemblances to Mars south polar cap and echoes from three icy Galilean satellites suggest that these craters too may have polar ice on Mercury. The effect of subsurface H20 on impact craters is a decrease in its d/D ratio, and softening of crater rims over a period of time. The study of Barlow et al., focused on determining the d/D ratios of 170 impact craters in the Borealis (north polar), Tolstoj (equatorial), Kuiper (equatorial), and Bach (south polar) quadrangles. This work focuses on the newly discovered radar bright craters, investigating their d/D ratios as an expansion of the earlier work..We compare our results to the statistical results from Barlow et al. here. With the upcoming Messenger spacecraft mission to Mercury, this is an especially timely study

  2. Intrinsic stress mitigation via elastic softening during two-step electrochemical lithiation of amorphous silicon

    Science.gov (United States)

    Jia, Zheng; Li, Teng

    2016-06-01

    Recent experiments and first-principles calculations show the two-step lithiation of amorphous silicon (a-Si). In the first step, the lithiation progresses by the movement of a sharp phase boundary between a pristine a-Si phase and an intermediate L iη Si phase until the a-Si phase is fully consumed. Then the second step sets in without a visible interface, with the L iη Si phase continuously lithiating to a L i3.75 Si phase. This unique feature of lithiation is believed to have important consequences for mechanical durability of a-Si anodes in lithium ion batteries, however the mechanistic understanding of such consequences is still elusive so far. Here, we reveal an intrinsic stress mitigation mechanism due to elastic softening during two-step lithiation of a-Si, via chemo-mechanical modeling. We find that lithiation-induced elastic softening of a-Si leads to effective stress mitigation in the second step of lithiation. These mechanistic findings allow for the first time to quantitatively predict the critical size of an a-Si anode below which the anode becomes immune to lithiation-induced fracture, which is in good agreement with experimental observations. Further studies on lithiation kinetics suggest that the two-step lithiation also results in a lower stress-induced energy barrier for lithiation. The present study reveals the physical underpinnings of previously unexplained favorable lithiation kinetics and fracture behavior of a-Si anodes, and thus sheds light on quantitative design guidelines toward high-performance anodes for lithium ion batteries.

  3. Direct Cytoskeleton Forces Cause Membrane Softening in Red Blood Cells

    Science.gov (United States)

    Rodríguez-García, Ruddi; López-Montero, Iván; Mell, Michael; Egea, Gustavo; Gov, Nir S.; Monroy, Francisco

    2015-01-01

    Erythrocytes are flexible cells specialized in the systemic transport of oxygen in vertebrates. This physiological function is connected to their outstanding ability to deform in passing through narrow capillaries. In recent years, there has been an influx of experimental evidence of enhanced cell-shape fluctuations related to metabolically driven activity of the erythroid membrane skeleton. However, no direct observation of the active cytoskeleton forces has yet been reported to our knowledge. Here, we show experimental evidence of the presence of temporally correlated forces superposed over the thermal fluctuations of the erythrocyte membrane. These forces are ATP-dependent and drive enhanced flickering motions in human erythrocytes. Theoretical analyses provide support for a direct force exerted on the membrane by the cytoskeleton nodes as pulses of well-defined average duration. In addition, such metabolically regulated active forces cause global membrane softening, a mechanical attribute related to the functional erythroid deformability. PMID:26083919

  4. Cellulase Activity and Fruit Softening in Avocado 1

    Science.gov (United States)

    Pesis, Edna; Fuchs, Yoram; Zauberman, Giora

    1978-01-01

    Cellulase activity in detached avocado (Persea americana Mill.) fruits was found to be directly correlated with ripening processes such as climacteric rise of respiration, ethylene evolutin, and softening. This activity in the pericarp could be induced by ethylene treatment, and the more mature the fruit—the faster and the greater was the response. Only a very low cellulase activity could be detected in hard avocado fruit right after harvest. Cellulase activity was highest at the distal end of the fruit, lower in the midsection, and lowest at the proximal end. The enzyme is heat-labile and appeared to have activity of an endocellulase nature mainly. Electron micrographs of cell walls from hard and soft fruits are presented. ImagesFig. 4 PMID:16660305

  5. A truly Newtonian softening length for disc simulations

    CERN Document Server

    Huré, Jean-Marc

    2014-01-01

    The softened point mass model is commonly used in simulations of gaseous discs including self-gravity while the value of associated length \\lambda remains, to some degree, controversial. This ``parameter'' is however fully constrained when, in a discretized disc, all fluid cells are demanded to obey Newton's law. We examine the topology of solutions in this context, focusing on cylindrical cells more or less vertically elongated. We find that not only the nominal length depends critically on the cell's shape (curvature, radial extension, height), but it is either a real or an imaginary number. Setting \\lambda as a fraction of the local disc thickness -- as usually done -- is indeed not the optimal choice. We then propose a novel prescription valid irrespective of the disc properties and grid spacings. The benefit, which amounts to 2-3 more digits typically, is illustrated in a few concrete cases. A detailed mathematical analysis is in progress.

  6. Ion transport and softening in a polymerized ionic liquid

    Science.gov (United States)

    Kumar, Rajeev; Bocharova, Vera; Strelcov, Evgheni; Tselev, Alexander; Kravchenko, Ivan I.; Berdzinski, Stefan; Strehmel, Veronika; Ovchinnikova, Olga S.; Minutolo, Joseph A.; Sangoro, Joshua R.; Agapov, Alexander L.; Sokolov, Alexei P.; Kalinin, Sergei V.; Sumpter, Bobby G.

    2014-12-01

    Polymerized ionic liquids (PolyILs) are promising materials for various solid state electronic applications such as dye-sensitized solar cells, lithium batteries, actuators, field-effect transistors, light emitting electrochemical cells, and electrochromic devices. However, fundamental understanding of interconnection between ionic transport and mechanical properties in PolyILs is far from complete. In this work, local charge transport and structural changes in films of a PolyIL are studied using an integrated experiment-theory based approach. Experimental data for the kinetics of charging and steady state current-voltage relations can be explained by taking into account the dissociation of ions under an applied electric field (known as the Wien effect). Onsager's theory of the Wien effect coupled with the Poisson-Nernst-Planck formalism for the charge transport is found to be in excellent agreement with the experimental results. The agreement between the theory and experiments allows us to predict structural properties of the PolyIL films. We have observed significant softening of the PolyIL films beyond certain threshold voltages and formation of holes under a scanning probe microscopy (SPM) tip, through which an electric field was applied. The observed softening is explained by the theory of depression in glass transition temperature resulting from enhanced dissociation of ions with an increase in applied electric field.Polymerized ionic liquids (PolyILs) are promising materials for various solid state electronic applications such as dye-sensitized solar cells, lithium batteries, actuators, field-effect transistors, light emitting electrochemical cells, and electrochromic devices. However, fundamental understanding of interconnection between ionic transport and mechanical properties in PolyILs is far from complete. In this work, local charge transport and structural changes in films of a PolyIL are studied using an integrated experiment-theory based approach

  7. Fracture simulation of elastomer blended polypropylene based on elastoviscoplastic constitutive equation with craze and tensile softening law

    Science.gov (United States)

    Mae, H.

    2006-08-01

    The strong strain-rate dependence, neck propagation and craze evolution characterize the large plastic deformation and fracture behavior of polymer. In the latest study, Kobayashi, Tomii and Shizawa suggested the elastoviscoplastic constitutive equation based on craze evolution and annihilation and then applied it to the plane strain issue of polymer. In the previous study, the author applied their suggested elastoviscoplastic constitutive equation with craze effect to the three dimensional shell and then showed that the load displacement history was in good agreement with the experimental result including only microscopic crack such as crazes. For the future industrial applications, the macroscopic crack has to be taken into account. Thus, the main objective of this study is to propose the tensile softening equation and then add it to the elastoviscoplastic constitutive equation with craze effect so that the load displacement history can be roughly simulated during the macroscopic crack propagation. The tested material in this study is the elastomer blended polypropylene used in the interior and exterior of automobiles. First, the material properties are obtained based on the tensile test results at wide range of strain rates: 10 - 4-102 (1/sec). Next, the compact tension test is conducted and then the tensile softening parameters are fixed. Then, the dart impact test is carried out in order to obtain the load displacement history and also observe the macroscopic crack propagation at high strain rate. Finally, the fracture behavior is simulated and then compared with the experimental results. It is shown that the predictions of the constitutive equation with the proposed tensile softening equation are in good agreement with the experimental results for the future industrial applications.

  8. Simulación del haz de electrones en un TEM como flujo de partículas cargadas

    Directory of Open Access Journals (Sweden)

    Alberto Hernández-Valle

    2015-03-01

    Full Text Available Se simuló el comportamiento de un haz de electrones en un Microscopio Electrónico de Transmisión (TEM en función del voltaje de aceleración, la corriente de excitación de las lentes y la permeabilidad relativa de las piezas polares, por medio del software COMSOL Multiphysics versión 4.2a. Los resultados mostraron una baja velocidad vertical en los electrones dispersos, los cuales fueron filtrados por los diafragmas. Además, los gráficos expusieron que la densidad del flujo magnético aumentó con el incremento en la permeabilidad magnética de las piezas polares. Además, un aumento en la densidad del flujo magnético incrementó el ángulo de los electrones divergentes y redujo su velocidad vertical. Finalmente, las observaciones demostraron que el número de electrones que entran en el sistema no afecta el comportamiento general del haz ni la magnitud de la densidad del flujo magnético.

  9. Characterization of microstructure of HAZs in as-welded and service condition of P91 pipe weldments

    Science.gov (United States)

    Pandey, C.; Giri, A.; Mahapatra, M. M.; Kumar, P.

    2017-01-01

    Steels 9-12% Cr, having the high creep rupture strength are advocated for the modern low polluting thermal power plants. In the present investigation, the P91 pipe weldments have been characterized for microstructural responses in as-welded, post-weld heat treatment (PWHT) and ageing conditions. The PWHT of welded samples were carried out at 760 °C for time of 2 h and ageing at 760 °C for 720 h and 1440 h, respectively. The effect of time has been studied on precipitates size, distribution of precipitates and grain sizes present in various zones of P91 steel weldments. The impact toughness and hardness variation of heat affected zone (HAZ) have also been studied in as-welded condition as well as at different heat treatment condition. A significant change was observed in grain size and precipitates size after each heat treatment condition. The maximum impact toughness of HAZ was obtained after PWHT at 760 °C for 2 h. The main phase observed in weld fusion zone in as-welded, PWHT and ageing conditions were M23C6, MX, M7C3, Fe-rich M3C and M2C. The unwanted Z-phase (NbCrN) was also noticed in weld fusion zone after ageing of 1440 h.

  10. Corrosion Behavior of Metal Active Gas Welded Joints of a High-Strength Steel for Automotive Application

    Science.gov (United States)

    Garcia, Mainã Portella; Mantovani, Gerson Luiz; Vasant Kumar, R.; Antunes, Renato Altobelli

    2017-09-01

    In this work, the corrosion behavior of metal active gas-welded joints of a high-strength steel with tensile yield strength of 900 MPa was investigated. The welded joints were obtained using two different heat inputs. The corrosion behavior has been studied in a 3.5 wt.% NaCl aqueous solution using electrochemical impedance spectroscopy and potentiodynamic polarization tests. Optical microscopy images, scanning electron microscopy and transmission electron microscopy with energy-dispersive x-ray revealed different microstructural features in the heat-affected zone (HAZ) and the weld metal (WM). Before and after the corrosion process, the sample was evaluated by confocal laser scanning microscopy to measure the depth difference between HAZ and WM. The results showed that the heat input did not play an important role on corrosion behavior of HSLA steel. The anodic and cathodic areas of the welded joints could be associated with depth differences. The HAZ was found to be the anodic area, while the WM was cathodic with respect to the HAZ. The corrosion behavior was related to the amount and orientation nature of carbides in the HAZ. The microstructure of the HAZ consisted of martensite and bainite, whereas acicular ferrite was observed in the weld metal.

  11. Material characterization of the encapsulation of an ultrasound contrast microbubble and its subharmonic response: strain-softening interfacial elasticity model.

    Science.gov (United States)

    Paul, Shirshendu; Katiyar, Amit; Sarkar, Kausik; Chatterjee, Dhiman; Shi, William T; Forsberg, Flemming

    2010-06-01

    Two nonlinear interfacial elasticity models--interfacial elasticity decreasing linearly and exponentially with area fraction--are developed for the encapsulation of contrast microbubbles. The strain softening (decreasing elasticity) results from the decreasing association between the constitutive molecules of the encapsulation. The models are used to find the characteristic properties (surface tension, interfacial elasticity, interfacial viscosity and nonlinear elasticity parameters) for a commercial contrast agent. Properties are found using the ultrasound attenuation measured through a suspension of contrast agent. Dynamics of the resulting models are simulated, compared with other existing models and discussed. Imposing non-negativity on the effective surface tension (the encapsulation experiences no net compressive stress) shows "compression-only" behavior. The exponential and the quadratic (linearly varying elasticity) models result in similar behaviors. The validity of the models is investigated by comparing their predictions of the scattered nonlinear response for the contrast agent at higher excitations against experimental measurement. All models predict well the scattered fundamental response. The nonlinear strain softening included in the proposed elastic models of the encapsulation improves their ability to predict subharmonic response. They predict the threshold excitation for the initiation of subharmonic response and its subsequent saturation.

  12. Effect of acoustic softening on the thermal-mechanical process of ultrasonic welding.

    Science.gov (United States)

    Chen, Kunkun; Zhang, Yansong; Wang, Hongze

    2017-03-01

    Application of ultrasonic energy can reduce the static stress necessary for plastic deformation of metallic materials to reduce forming load and energy, namely acoustic softening effect (ASE). Ultrasonic welding (USW) is a rapid joining process utilizing ultrasonic energy to form a solid state joint between two or more pieces of metals. Quantitative characterization of ASE and its influence on specimen deformation and heat generation is essential to clarify the thermal-mechanical process of ultrasonic welding. In the present work, experiments were set up to found out mechanical behavior of copper and aluminum under combined effect of compression force and ultrasonic energy. Constitutive model was proposed and numerical implemented in finite element model of ultrasonic welding. Thermal-mechanical analysis was put forward to explore the effect of ultrasonic energy on the welding process quantitatively. Conclusions can be drawn that ASE increases structural deformation significantly, which is beneficial for joint formation. Meanwhile, heat generation from both frictional work and plastic deformation is slightly influenced by ASE. Based on the proposed model, relationship between ultrasonic energy and thermal-mechanical behavior of structure during ultrasonic welding was constructed.

  13. Alloy hardening and softening in binary molybdenum alloys as related to electron concentration.

    Science.gov (United States)

    Stephens, J. R.; Witzke, W. R.

    1972-01-01

    Determination of the effects of alloy additions of Hf, Ta, W, Re, Os, Ir, and Pt on the hardness of Mo. Special emphasis was placed on alloy softening in these binary Mo alloys. A modified microhardness test unit permitted hardness determinations at homologous temperatures ranging from 0.02 to 0.15, where alloy softening normally occurs in bcc alloys. Results showed that alloy softening was produced by those elements having an excess of s + d electrons compared to Mo while those elements having an equal number or fewer s + d electrons than Mo failed to produce alloy softening. The magnitude of the softening and the amount of solute element at the hardness minimum diminished rapidly with increasing test temperature. At solute concentrations where alloy softening was observed, the temperature sensitivity of hardness was lowered. For solute elements having an excess of s + d electrons or fewer s + d electrons than Mo, alloy softening and alloy hardening can be correlated with the difference in number of s + d electrons of the solute element and Mo.

  14. Life cycle assessment of central softening of very hard drinking water.

    Science.gov (United States)

    Godskesen, B; Hauschild, M; Rygaard, M; Zambrano, K; Albrechtsen, H-J

    2012-08-30

    Many consumers prefer softened water due to convenience issues such as avoidance of removing limescale deposits from household appliances and surfaces, and to reduce consumption of cleaning agents and laundry detergents leading to lower household expenses. Even though central softening of drinking water entailed an increased use of energy, sand and chemicals at the waterworks, the distributed and softened drinking water supported a decrease in consumption of energy and chemical agents in the households along with a prolonged service life of household appliances which heat water. This study used Life Cycle Assessment (LCA) to quantify the environmental impacts of central softening of drinking water considering both the negative effects at the waterworks and the positive effects imposed by the changed water quality in the households. The LCA modeling considered central softening of drinking water from the initial hardness of the region of study (Copenhagen, Denmark) which is 362 mg/L as CaCO(3) to a final hardness as CaCO(3) of 254 (a softening depth of 108) mg/L or 145 (a softening depth of 217) mg/L. Our study showed that the consumer preference can be met together with reducing the impact on the environment and the resource consumption. Environmental impacts decreased by up to 3 mPET (milli Personal Equivalent Targeted) and the break-even point from where central softening becomes environmentally beneficial was reached at a softening depth of only 22 mg/L as CaCO(3). Both energy-related and chemically related environmental impacts were reduced as well as the consumption of resources. Based on scarcity criteria, nickel was identified as the most problematic non-renewable resource in the system, and savings of up to 8 mPR (milli Person Reserve) were found.

  15. Elastic and mechanical softening in boron-doped diamond

    Science.gov (United States)

    Liu, Xiaobing; Chang, Yun-Yuan; Tkachev, Sergey N.; Bina, Craig R.; Jacobsen, Steven D.

    2017-01-01

    Alternative approaches to evaluating the hardness and elastic properties of materials exhibiting physical properties comparable to pure diamond have recently become necessary. The classic linear relationship between shear modulus (G) and Vickers hardness (HV), along with more recent non-linear formulations based on Pugh’s modulus extending into the superhard region (HV > 40 GPa) have guided synthesis and identification of novel superabrasives. These schemes rely on accurately quantifying HV of diamond-like materials approaching or potentially exceeding the hardness of the diamond indenter, leading to debate about methodology and the very definition of hardness. Elasticity measurements on such materials are equally challenging. Here we used a high-precision, GHz-ultrasonic interferometer in conjunction with a newly developed optical contact micrometer and 3D optical microscopy of indentations to evaluate elasticity-hardness relations in the ultrahard range (HV > 80 GPa) by examining single-crystal boron-doped diamond (BDD) with boron contents ranging from 50–3000 ppm. We observe a drastic elastic-mechanical softening in highly doped BDD relative to the trends observed for superhard materials, providing insight into elasticity-hardness relations for ultrahard materials. PMID:28233808

  16. Remineralizing agents: effects on acid-softened enamel.

    Science.gov (United States)

    Porcelli, H Bp; Maeda, F A; Silva, B R; Miranda, W G; Cardoso, P Ec

    2015-01-01

    This study sought to evaluate whether remineralizing toothpastes can protect acid-softened enamel against further erosive episodes. Fifty enamel slabs of bovine teeth with preformed erosion-like lesions were randomly assigned to 1 control and 4 experimental groups (n = 10): group 1, nanohydroxyapatite (nanoHAp) dentifrice; group 2, arginine and calcium carbonate (CaCO3) dentifrice; group 3, potassium nitrate (KNO3) and high-fluoride (F) availability dentifrice; group 4, ordinary fluoridated dentifrice (OFD); and group 5, control (deionized water). Initial hardness measurements were taken after the different treatments were applied. Statistically significant mineral gains of 8.0% and 10.0% were exhibited in groups 1 and 4, respectively. Groups 2 and 3 showed mineral gains of 4.5% and 2.1%, respectively; these were not statistically significant. Group 5 showed mineral loss (-11.8%). A 1-way analysis of variance showed no statistically significant differences in the mean microhardness values among groups. However, there are indications that the nanoHAp and OFD toothpastes may decrease erosive lesions after treatment, while the arginine + CaCO3 and KNO3 + F pastes may prevent the progression of erosive lesions.

  17. Elastic and mechanical softening in boron-doped diamond.

    Science.gov (United States)

    Liu, Xiaobing; Chang, Yun-Yuan; Tkachev, Sergey N; Bina, Craig R; Jacobsen, Steven D

    2017-02-24

    Alternative approaches to evaluating the hardness and elastic properties of materials exhibiting physical properties comparable to pure diamond have recently become necessary. The classic linear relationship between shear modulus (G) and Vickers hardness (HV), along with more recent non-linear formulations based on Pugh's modulus extending into the superhard region (HV > 40 GPa) have guided synthesis and identification of novel superabrasives. These schemes rely on accurately quantifying HV of diamond-like materials approaching or potentially exceeding the hardness of the diamond indenter, leading to debate about methodology and the very definition of hardness. Elasticity measurements on such materials are equally challenging. Here we used a high-precision, GHz-ultrasonic interferometer in conjunction with a newly developed optical contact micrometer and 3D optical microscopy of indentations to evaluate elasticity-hardness relations in the ultrahard range (HV > 80 GPa) by examining single-crystal boron-doped diamond (BDD) with boron contents ranging from 50-3000 ppm. We observe a drastic elastic-mechanical softening in highly doped BDD relative to the trends observed for superhard materials, providing insight into elasticity-hardness relations for ultrahard materials.

  18. Elastic and mechanical softening in boron-doped diamond

    Science.gov (United States)

    Liu, Xiaobing; Chang, Yun-Yuan; Tkachev, Sergey N.; Bina, Craig R.; Jacobsen, Steven D.

    2017-02-01

    Alternative approaches to evaluating the hardness and elastic properties of materials exhibiting physical properties comparable to pure diamond have recently become necessary. The classic linear relationship between shear modulus (G) and Vickers hardness (HV), along with more recent non-linear formulations based on Pugh’s modulus extending into the superhard region (HV > 40 GPa) have guided synthesis and identification of novel superabrasives. These schemes rely on accurately quantifying HV of diamond-like materials approaching or potentially exceeding the hardness of the diamond indenter, leading to debate about methodology and the very definition of hardness. Elasticity measurements on such materials are equally challenging. Here we used a high-precision, GHz-ultrasonic interferometer in conjunction with a newly developed optical contact micrometer and 3D optical microscopy of indentations to evaluate elasticity-hardness relations in the ultrahard range (HV > 80 GPa) by examining single-crystal boron-doped diamond (BDD) with boron contents ranging from 50–3000 ppm. We observe a drastic elastic-mechanical softening in highly doped BDD relative to the trends observed for superhard materials, providing insight into elasticity-hardness relations for ultrahard materials.

  19. Experimental evidence of zone-center optical phonon softening by accumulating holes in thin Ge

    Energy Technology Data Exchange (ETDEWEB)

    Kabuyanagi, Shoichi; Nishimura, Tomonori; Yajima, Takeaki; Toriumi, Akira [Department of Materials Engineering, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-8656 (Japan)

    2016-01-15

    We discuss the impact of free carriers on the zone-center optical phonon frequency in germanium (Ge). By taking advantage of the Ge-on-insulator structure, we measured the Raman spectroscopy by applying back-gate bias. Phonon softening by accumulating holes in Ge film was clearly observed. This fact strongly suggests that the phonon softening in heavily-doped Ge is mainly attributed to the free carrier effect rather than the dopant atom counterpart. Furthermore, we propose that the free carrier effect on phonon softening is simply understandable from the viewpoint of covalent bonding modification by free carriers.

  20. Surface grain coarsening and surface softening during machining of ultra-fine grained titanium

    Directory of Open Access Journals (Sweden)

    Symonova A.A.

    2012-01-01

    Full Text Available Experiments are run to show that different machining conditions applied to ultra-fine grained pure titanium lead to different levels of grain coarsening and softening near the machined surface. Under “hard” machining conditions the upper 40 microns of the machined surface are altered with a decreased microhardness. The experimental results are reasonably reproduced by model calculations. Expanding the parameter field of the model calculations, the surface coarsening diagram and the surface softening diagram due to machining are presented, showing the region of technological parameters, under which neither grain coarsening nor softening takes place along the machined surface.

  1. Long-term Creep Life Prediction and Its Reliability on HAZ Failure Data of Grade 91 Steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Woo Gon; Jang, Jin Sung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Jae Young [Pukyong National University, Busan (Korea, Republic of)

    2015-10-15

    Long-term creep life prediction on Grade 91 HAZ failure data was performed by LM parameter, and its reliability was successfully demonstrated using SCRI model based on Z-parameter. To improve the creep life prediction at the low stress range of high temperature range, the master curve with a 'sinh' function was newly proposed. By Monte-Carlo simulation, reliability assessment was made using the chosen service temperature and stress conditions. carbide/nitride forming elements such as V and Nb along with controlled addition of N in the plain 9Cr. 1Mo steel, offers a good combination of high creep strength and ductility over prolonged exposures at elevated temperatures. The choice of Gr. 91 steel for sodium-cooled fast reactor (SFR) applications is guided by its low thermal expansion coefficient and high resistance to stress corrosion cracking in water-steam systems compared to austenitic stainless steels.

  2. Perfect softening of the ferroelectric mode in the isotope-exchanged strontium titanate of SrTi18O3 studied by light scattering.

    Science.gov (United States)

    Takesada, M; Itoh, M; Yagi, T

    2006-06-09

    The mode of the isotope-induced ferroelectric strontium titanate shows a perfect softening at the ferroelectric phase transition temperature , where the frequency of the underdamped mode approaches completely to zero within the instrumental resolution. The spectra of the Raman inactive soft mode have been successfully observed owing to local symmetry breaking and by long-term accumulation of the spectral intensity with a high resolution technique. The mechanism of the phase transition is concluded to be an ideal displacive-type accompanied with perfect softening of the Slater-type polar mode. The difference between the soft mode behavior of and indicates that the origin of the quantum paraelectric state of lies in the quantum fluctuation of the oxide octahedron in the perovskite structure.

  3. Susceptibility and occurrence condition of HAZ liquation cracking on rail steels. Report 4. Study on rail welding with high-C welding materials; Reru ko no HAZ ekika ware hassei joken to ware kanjusei. 4. Reru no kotanso yoyu yosetsu gijutsu no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Karimine, K.; Uchino, K.; Okumura, M. [Nippon Steel Corp., Tokyo (Japan)

    1996-08-05

    In connection with HAZ liquation cracks which occur in the low-C EAW method which is currently used as a field welding process for rails, the effects of the critical carbon content and the critical welding conditions necessary for avoiding crack occurrence are elucidated, and the susceptibility of HAZ liquation cracks for rails is investigated to study the mechanism of crack occurrence. The trend of HAZ liquation cracks of rails is closely related to the difference in the C contents in the weld metal and the base rail metal, and the crack incidence increases with the increase in the difference of the C content in the range of higher than 0.3% C content. On the other hand, crack incidence can be avoided if the difference in the C content is less than 0.2%. Higher welding heat input increases HAZ liquation crack incidence with larger difference in the C contents between the weld metal and the base metal. When the difference in the C content is large, it is desirable to limit the use of high current using large size welding rods. Purification of steel materials by reducing such impurity elements as P and S is effective to reduce the susceptibility of HAZ liquation cracks. 9 refs., 15 figs., 5 tabs.

  4. Structural and thermodynamical properties of charged hard spheres in a mixture with core-softened model solvent.

    Science.gov (United States)

    Lukšič, Miha; Hribar-Lee, Barbara; Vlachy, Vojko; Pizio, O

    2012-12-28

    The canonical Monte Carlo computer simulations and integral equation theory were applied to examine the structural and thermodynamic properties of a mixture of ions and a core-softened fluid molecules. The positive and negative ions forming a +1:-1 salt were modeled as charged hard spheres, immersed in the dielectric medium. It was shown previously that the core-softened fluid under study is characterized by a set of structural, thermodynamic, and dynamic anomalies. The principal objective of this work was to elucidate how the presence of ions alters this behavior. The structural properties of the mixtures are discussed in terms of the pair distribution functions; in addition, the pair contribution to the excess entropy was calculated. Thermodynamic properties are investigated by using the dependencies of energy and compressibility factor on density, composition of the mixture, and reduced temperature. The heat capacity was also evaluated. Our principal findings concern the description of structural anomalies in the mixture, the dependence of the temperature of maximum density on the ionic concentration, and establishing the regions delimiting the structural and thermodynamic anomalies of the model mixture.

  5. Nonlinear dynamics of spring softening and hardening in folded-mems comb drive resonators

    KAUST Repository

    Elshurafa, Amro M.

    2011-08-01

    This paper studies analytically and numerically the spring softening and hardening phenomena that occur in electrostatically actuated microelectromechanical systems comb drive resonators utilizing folded suspension beams. An analytical expression for the electrostatic force generated between the combs of the rotor and the stator is derived and takes into account both the transverse and longitudinal capacitances present. After formulating the problem, the resulting stiff differential equations are solved analytically using the method of multiple scales, and a closed-form solution is obtained. Furthermore, the nonlinear boundary value problem that describes the dynamics of inextensional spring beams is solved using straightforward perturbation to obtain the linear and nonlinear spring constants of the beam. The analytical solution is verified numerically using a Matlab/Simulink environment, and the results from both analyses exhibit excellent agreement. Stability analysis based on phase plane trajectory is also presented and fully explains previously reported empirical results that lacked sufficient theoretical description. Finally, the proposed solutions are, once again, verified with previously published measurement results. The closed-form solutions provided are easy to apply and enable predicting the actual behavior of resonators and gyroscopes with similar structures. © 2011 IEEE.

  6. Development of cellulose-polypyrrole microfiber membranes and assessment of their capability on water softening

    Science.gov (United States)

    Barrera, C.; Arrieta, A.; Escobar, N.; Gañan, P.; Castro, C.

    2013-11-01

    The application of conducting polymer composite for water softening is based on the use of pyrrole's electrochemical properties joined with the flexibility and relatively high surface areas associated with cellulose fibers, to develop a new hybrid material that exhibits the inherent proprieties of both components. This hybrid would allow to promote an ion exchange reaction between the composite membrane and the hard water. The cellulose membranes obtained from banana plant agricultural waste (raquis), were uniform with individual and well separated fibers. The fibers were encapsulated by a continuous coating of polypyrrole by an in situ oxidative chemical polymerization. The amount of polypyrrole deposited on the fiber increased by increasing the monomer concentration, behavior that was identified through the observation of differences on the intensity of the light to dark color shift that coated the fibers after the polymerization. The ion removal capability of the membrane coted with the conducting polymer was tested using an experimental device, finding reductions on the conductivity for hard water within 23 to 66 μs/cm after 6 hours of the assay.

  7. Strain rate dependent deformation and failure behavior of laser welded DP780 steel joint under dynamic tensile loading

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yang, E-mail: liuyang@mail.neu.edu.cn [Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education, Northeastern University, Shenyang 110819 (China); Dong, Danyang, E-mail: dongdanyang@mail.neu.edu.cn [College of Science, Northeastern University, Shenyang 110819 (China); Wang, Lei, E-mail: wanglei@mail.neu.edu.cn [Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education, Northeastern University, Shenyang 110819 (China); Chu, Xi, E-mail: chuxi.ok@163.com [College of Science, Northeastern University, Shenyang 110819 (China); Wang, Pengfei, E-mail: wpf1963871400@163.com [College of Science, Northeastern University, Shenyang 110819 (China); Jin, Mengmeng, E-mail: 24401878@163.com [College of Science, Northeastern University, Shenyang 110819 (China)

    2015-03-11

    Laser welded DP steel joints are used widely in the automotive industry for weight reduction. Understanding the deformation and fracture behavior of the base metal (BM) and its welded joint (WJ), especially at high strain rates, is critical for the design of vehicle structures. This paper is concerned with the effects of strain rate on the tensile properties, deformation and fracture behavior of the laser welded DP780 steel joint. Quasi-static and dynamic tensile tests were performed on the WJ and BM of the DP780 steel using an electromechanical universal testing machine and a high-speed tensile testing machine over a wide range of strain rate (0.0001–1142 s{sup −1}). The microstructure change and microhardness distribution of the DP780 steel after laser welding were examined. Digital image correlation (DIC) and high-speed photography were employed for the strain measurement of the DP780 WJ during dynamic tensile tests. The DP780 WJ is a heterogeneous structure with hardening in fusion zone (FZ) and inner heat-affected zone (HAZ), and softening in outer HAZ. The DP780 BM and WJ exhibit positive strain rate dependence on the YS and UTS, which is smaller at lower strain rates and becomes larger with increasing strain rate, while ductility in terms of total elongation (TE) tends to increase under dynamic loading. Laser welding leads to an overall reduction in the ductility of the DP780 steel. However, the WJ exhibits a similar changing trend of the ductility to that of the BM with respect to the strain rate over the whole strain rate range. As for the DP780 WJ, the distance of tensile failure location from the weld centerline decreases with increasing strain rate. The typical ductile failure characteristics of the DP780 BM and WJ do not change with increasing strain rate. DIC measurements reveal that the strain localization starts even before the maximum load is attained in the DP780 WJ and gradual transition from uniform strains to severely localized strains

  8. The Softening of Hard Water and Complexometric Titrations. An Undergraduate Experiment

    Science.gov (United States)

    Ceretti, Helena; Hughes, Enrique A.; Zalts, Anita

    1999-10-01

    A 2-hour experiment for undergraduates is presented in which (i) water hardness is explained and demonstrated; (ii) ion-exchange resin properties are visually demonstrated and then used for softening water; (iii) complexometric titrations are used for evaluating water hardness before and after softening; and (iv) acid-base titration can be used to show that the Ca/Mg ions removed by the ion exchanger are replaced by H ions.

  9. Comparison of shear banding in BMGs due to thermal-softening and free volume creation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper reports a comparative study of shear banding in BMGs resulting from thermal softening and free volume creation. Firstly,the effects of thermal softening and free volume creation on shear instability are discussed. It is known that ther-mal softening governs thermal shear banding,hence it is essentially energy related. However,compound free volume creation is the key factor to the other instability,though void-induced softening seems to be the counterpart of thermal softening. So,the driving force for shear instability owing to free volume creation is very dif-ferent from the thermally assisted one. In particular,long wave perturbations are always unstable owing to compound free volume creation. Therefore,the shear instability resulting from coupled compound free volume creation and thermal softening may start more like that due to free volume creation. Also,the compound free volume creation implies a specific and intrinsic characteristic growth time of shear instability. Finally,the mature shear band width is governed by the corre-sponding diffusions (thermal or void diffusion) within the band. As a rough guide,the dimensionless numbers: Thermal softening related number B,Deborah number (denoting the relation of instability growth rate owing to compound free volume and loading time) and Lewis number (denoting the competition of different diffusions) show us their relative importance of thermal softening and free volume creation in shear banding. All these results are of particular significance in understanding the mechanism of shear banding in bulk metallic glasses (BMGs).

  10. Cost-benefit analysis of central softening for production of drinking water.

    Science.gov (United States)

    Van der Bruggen, B; Goossens, H; Everard, P A; Stemgée, K; Rogge, W

    2009-01-01

    Softening drinking water before distribution yields advantages with environmental impact, such as lower household products consumption, less scaling in piping and machines, and the avoidance of decentralized, domestic softeners. Central softening is under consideration in Flanders by the largest water supplier, VMW (Dutch acronym for "Flemish Company for Water Supply"), to deliver soft (15 degrees F) water to their customers. A case study is presented for a region with hard water (47 degrees F). The chosen technique is the pellet reactor, based on precipitation of CaCO(3) by NaOH addition. This softening operation has possibly large impact on the environment and the water consumption pattern. A cost-benefit analysis has been made to estimate the added value of central softening, by investigating the impact on the drinking water company, on their customers, on employment, on environment, on health, etc. The analysis for the region of study revealed benefits for customers which were higher than the costs for the drinking water company. However, pricing of drinking water remains an important problem. A sensitivity analysis of these results has also been made, to evaluate the impact of important hypothesis, and to be able to expand this study to other regions. The conclusions for this part show that softening is beneficial if water hardness is to be decreased by at least 5 degrees F.

  11. A novel eco-friendly technique for efficient control of lime water softening process.

    Science.gov (United States)

    Ostovar, Mohamad; Amiri, Mohamad

    2013-12-01

    Lime softening is an established type of water treatment used for water softening. The performance of this process is highly dependent on lime dosage. Currently, lime dosage is adjusted manually based on chemical tests, aimed at maintaining the phenolphthalein (P) and total (M) alkalinities within a certain range (2 P - M > or = 5). In this paper, a critical study of the softening process has been presented. It has been shown that the current method is frequently incorrect. Furthermore, electrical conductivity (EC) has been introduced as a novel indicator for effectively characterizing the lime softening process.This novel technique has several advantages over the current alkalinities method. Because no chemical reagents are needed for titration, which is a simple test, there is a considerable reduction in test costs. Additionally, there is a reduction in the treated water hardness and generated sludge during the lime softening process. Therefore, it is highly eco-friendly, and is a very cost effective alternative technique for efficient control of the lime softening process.

  12. Dehydration softening of serpentine as a trigger of intermediate-depth earthquakes

    Science.gov (United States)

    Shimizu, I.; Watanabe, Y.; Michibayashi, K.; Uehara, S.; Takahashi, M.; Katsuta, N.

    2011-12-01

    slip was obtained in the SEM-EBSD analysis. Significant volume loss in the samples suggests compaction and escape of water during deformation experiments. Mechanical behaviors and microstructural features of the pre-heated samples both indicated that the dominant deformation mechanism was cataclastic flow and compaction of reaction products. The reacted samples showed "dehydration softening" rather than "embrittlement". In contrast, the same antigorite-serpentinite deformed in a gas-medium apparatus at a low confining pressure (200 MPa) exhibited a semi-brittle behavior. This fact suggests that dehydration embrittlement is only effective at the shallow to middle crustal levels. In the subducting slabs, strain localization at the serpentinized mantle due to dehydration softening and high fluid pressure caused by pore collapse possibly trigger earthquakes in surrounding peridotite mantle.

  13. Expansion of spherical cavity of strain-softening materials with different elastic moduli of tension and compression

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An expansion theory of spherical cavities in strain-softening materials with different moduli of tension and compression was presented. For geomaterials, two controlling parameters were introduced to take into account the different moduli and strain-softening properties. By means of elastic theory with different moduli and stress-softening models, g. eneral solutions calculating Tresca and Mohr-Coulomb materials' stress and displacement fields of expansion of spherical cavity were derived. The effects caused by different elastic moduli in tensile and compression and strain-softening rates on stress and displacement fields and development of plastic zone of expansion of cavity were analyzed. The results show that the ultimate expansion pressure,stress and displacement fields and development of plastic zone vary with the different elastic moduli and strain-softening properties. If classical elastic theory is adopted and strain-softening properties are neglected, rather large errors may be the result.

  14. Creep Rupture of the Simulated HAZ of T92 Steel Compared to that of a T91 Steel

    Directory of Open Access Journals (Sweden)

    Yu-Quan Peng

    2017-02-01

    Full Text Available The increased thermal efficiency of fossil power plants calls for the development of advanced creep-resistant alloy steels like T92. In this study, microstructures found in the heat-affected zone (HAZ of a T92 steel weld were simulated to evaluate their creep-rupture-life at elevated temperatures. An infrared heating system was used to heat the samples to 860 °C (around AC1, 900 °C (slightly below AC3, and 940 °C (moderately above AC3 for one minute, before cooling to room temperature. The simulated specimens were then subjected to a conventional post-weld heat treatment (PWHT at 750 °C for two hours, where both the 900 °C and 940 °C simulated specimens had fine grain sizes. In the as-treated condition, the 900 °C simulated specimen consisted of fine lath martensite, ferrite subgrains, and undissolved carbides, while residual carbides and fresh martensite were found in the 940 °C simulated specimen. The results of short-term creep tests indicated that the creep resistance of the 900 °C and 940 °C simulated specimens was poorer than that of the 860 °C simulated specimens and the base metal. Moreover, simulated T92 steel samples had higher creep strength than the T91 counterpart specimens.

  15. Characterization and occurence of eairly softening disorder in 'golden' papaya fruits

    Directory of Open Access Journals (Sweden)

    Angelo Pedro Jacomino

    2010-12-01

    Full Text Available The occurrence of green skin and soft pulp in 'Golden' papaya fruit during certain seasons has been reported by farmers in the northern of the state of Espirito Santo, Brazil. The objective of this study was to characterize and determine the occurrence of this disorder, which was referred as "early softening disorder". Fruits were harvested weekly for 11 months (from September to July. The fruits were stored at 10°C, and then fruit flesh firmness and skin color were analyzed. The results of the firmness test were submitted to regression analysis assuming a linear trendline. The slope of the curve was called the 'softening index' (SI. Fruits with early softening are characterized by a loss of firmness in less than 10 days, even when stored under refrigeration. Although softened, the skin of the fruit remains partially green. Fruits with the disorder occurred more frequently from mid-summer to mid-autumn (February to May. It is not possible to distinguish early softening disorder fruits from those without the disorder by skin color and flesh firmness analysis at the time of the harvest.

  16. Progressive failure analysis of slope with strain-softening behaviour based on strength reduction method

    Institute of Scientific and Technical Information of China (English)

    Ke ZHANG; Ping CAO; Rui BAO

    2013-01-01

    Based on the strength reduction method and strain-softening model,a method for progressive failure analysis of strain-softening slopes was presented in this paper.The mutation is more pronounced in strain-softening analysis,and the mutation of displacement at slope crest was taken as critical failure criterion.An engineering example was provided to demonstrate the validity of the present method.This method was applied to a cut slope in an industry site.The results are as follows: (1) The factor of safety and the critical slip surface obtained by the present method are between those by peak and residual strength.The analysis with peak strength would lead to non-conservative results,but that with residual strength tends to be overly conservative.(2) The thickness of the shear zone considering strain-softening behaviour is narrower than that with non-softening analysis.(3) The failure of slope is the process of the initiation,propagation and connection of potential failure surface.The strength parameters are mobilized to a non-uniform degree while progressive failure occurs in the slope.(4) The factor of safety increases with the increase of residual shear strain threshold and elastic modulus.The failure mode of slope changes from shallow slip to deep slip.Poisson's ratio and dilation angle have little effect on the results.

  17. Effects of water re-saturation conditions and associated extractives leaching on thermal softening of wet wood

    OpenAIRE

    BREMAUD, Iris; Bardet, Sandrine; Gril, Joseph; Perré, Patrick

    2014-01-01

    International audience; Thermal softening, or thermo-activated viscoelasticity, is involved in several industrial and/or traditional craftsmanship techniques processing of wood. More fundamentally, it represents a very useful probe of chemical differences and/or of physical histories of wood samples [1,2,3,4,5]. Thermal softening of wet (= water-saturated) wood occurs at much lower temperature than that of completely (anhydrous) dried wood [6,7]. Softening of oven-dry wood happens at temperat...

  18. Molds in Brined Cucumbers: Cause of Softening During Air-Purging of Fermentations †

    Science.gov (United States)

    Costilow, Ralph N.; Gates, Karen; Lacy, Melvyn L.

    1980-01-01

    Softening of cucumbers in fermentations purged at high air-flow rates was caused by molds growing in the brined cucumbers, not in the brine. This conclusion is based on the following results: (i) no microorganisms were isolated in significant numbers from brines that caused softening of pasteurized brined cucumbers, (ii) no pectinolytic enzyme activities were produced in cucumber brines in the absence of cucumbers, (iii) the pickles in some air-purged fermentations became very soft without the appearance of any pectinolytic enzyme activity in the brine, (iv) mold hyphae were consistently observed in tissues of soft pickles, (v) molds consistently developed in cultures of slices of surface sterilized cucumbers taken from fermentations in which soft pickles were subsequently found, and (vi) molds belonging to the genera Alternaria, Fusarium, and Mucor isolated from slices all softened pasteurized brined cucumbers. Images PMID:16345619

  19. STUDY ON SOFTENING AND DROPPING PROPERTIES OF METALIZED BURDEN INSIDE BLAST FURNACE

    Directory of Open Access Journals (Sweden)

    Bi-yang Tuo

    2014-12-01

    Full Text Available The inferences of burden metallization rate on softening-melting dropping properties were investigated through softening-melting dropping test of three kinds of metalized burden pressure drop. The results indicated that the softeningmelting temperature interval of pre-reduction mixed burden is bigger than primeval mixed burden, the melting interval narrow with the rise of metallization rate of ferric burden as well as dropping temperature interval. The average pressure drop, maximum pressure drop and softening-melting dropping properties eigenvalue decrease with the rise of metallization rate of ferric burden. Besides, the dropping temperature of burden reduces with the rise of carbon content of molten iron. The combination high metalized burden and higher carbon content of molten iron is benefit to decreasing thickness of cohesive zone and improve permeability of cohesive zone.

  20. Communication: Surface-facilitated softening of ordinary and vapor-deposited glasses

    Science.gov (United States)

    Cubeta, Ulyana; Bhattacharya, Deepanjan; Sadtchenko, Vlad

    2017-08-01

    A common distinction between the ordinary glasses formed by melt cooling and the stable amorphous films formed by vapor deposition is the apparent mechanism of their devitrification. Using quasi-adiabatic, fast scanning calorimetry that is capable of heating rates in excess of 105 K s-1, we have investigated the softening kinetics of micrometer-scale, ordinary glass films of methylbenzene and 2-propanol. At the limit of high heating rates, the transformation mechanism of ordinary glasses is identical to that of their stable vapor-deposited counterparts. In both cases, softening is likely to begin at the sample surface and progress into its bulk via a transformation front. Furthermore, such a surface-facilitated mechanism complies with zero-order, Arrhenius rate law. The activation energy barriers for the softening transformation imply that the kinetics must be defined, at least in part, by the initial thermodynamic and structural state of the samples.

  1. [Non-edematous spontaneously resolving cerebellar softening. Diagnostic possibilities and value (author's transl)].

    Science.gov (United States)

    Samson, M; Parain, D; Mihout, B

    1980-01-01

    Non edematous cerebellar softenings are usually unrecognized even though their relatively high frequency of occurrence is proved by systematic anatomical studies. They should be suspected when an acute late-onset vestibular syndrome is noted, in which there is a particular type of homolateral disequilibrium and nystagmus, good vestibular reactivity, and possible association with a cerebellar syndrome. Softening can usually be confirmed after several days by the complementary examinations presently available: computer tomography of the posterior fossa and scintigraphy with labelled bleomycin. Non-edematous forms are spontaneously resolving disorders but surveillance during the first few days is necessary together with anti-edematous therapy as early signs are common to those of edematous softening, responsible for rapid involvement of the brain stem and blocking of fluid pathways.

  2. Heterotrophic plate count and consumer's health under special consideration of water softeners.

    Science.gov (United States)

    Hambsch, Beate; Sacré, Clara; Wagner, Ivo

    2004-05-01

    The phenomenon of bacterial growth in water softeners is well known since years. To upgrade the hygienic safety of water softeners, the German DIN Standard 19636 was developed, to assure that the distribution system could not be contaminated by these devices and that the drinking water to be used in the household still meets the microbiological standards according to the German drinking water guidelines, i.e. among others heterotrophic plate count (HPC) below 100 CFU/ml. Moreover, the standard for the water softeners includes a test for contamination with Pseudomonas aeruginosa which has to be disinfected during the regeneration phase. This is possible by sanitizing the resin bed during regeneration by producing chlorine. The results of the last 10 years of tests of water softeners according to DIN 19636 showed that it is possible to produce water softeners that comply with that standard. Approximately 60% of the tested models were accepted. P. aeruginosa is used as an indicator for potentially pathogenic bacteria being able to grow also in low nutrient conditions which normally prevail in drinking water. Like other heterotrophs, the numbers of P. aeruginosa increase rapidly as stagnation occurs. Normally P. aeruginosa is not present in the distributed drinking water. However, under certain conditions, P. aeruginosa can be introduced into the drinking water distribution system, for instance, during construction work. The occurrence of P. aeruginosa is shown in different cases in treatment plants, public drinking water systems and in-house installations. The compliance with DIN 19636 provides assurance that a water softener will not be a constant source of contamination, even if it is once inoculated with a potentially pathogenic bacterium like P. aeruginosa.

  3. The Etiology and Treatment of the Softened Phallus after the Radial Forearm Osteocutaneous Free Flap Phalloplasty

    Directory of Open Access Journals (Sweden)

    Seok-Kwun Kim

    2012-07-01

    Full Text Available BackgroundThe radial forearm osteocutaneous free flap is considered to be the standard technique for penile construction. One year after their operation, most patients experience a softened phallus, so that they suffer from difficulties in sexual intercourse. In this report, we present our experience with phalloplasty by radial forearm osteocutaneous free flap, as well as an evaluation of the etiology and treatment of the softened phallus.MethodsBetween March 2005 and February 2010, 58 patients underwent phalloplasty by radial forearm osteocutaneous free flap. Most of their neophallus had been softened subjectively and among them, 12 patients who wanted correction were investigated. We performed repetitive fat injection, artificial dermis grafting, silicone rod insertion, and rib bone with cartilaginous tip graft. Physical examination, plain radiograph, computed tomography, bone scintigraphy, and satisfaction scores were investigated.ResultsMost of the participants' penises have been softened after phalloplasty, and the skin elasticity had been also decreased. On plain radiograph, the distal end of the bone was self-rounded; however, the bone shape of the neophallus had no significant interval changes or resorption. Computed tomography showed equivocal density of cortical bone. On bone scintigraphy, the bone metabolism was active at 3 months postoperatively, and remained active 9 years postoperatively.ConclusionsThe use of a rib bone with cartilaginous tip graft could be an option for improvement of the softened phallus. Silicon rod insertion is also worth considering for rigidity of the softened phallus. Decreased rigidity due to soft tissue atrophy could be alleviated with repeated fat injection and artificial dermis grafting.

  4. Optimization of Structure and Material Properties for Solids Composed of Softening Material

    DEFF Research Database (Denmark)

    Bendsøe, Martin P.; Guedes, J.M.; J.M., Plaxton;

    1996-01-01

    Recent results on the design of material properties in the context of global structural optimization provide, in analytical form, a prediction of the optimal material tensor distributions for two or three dimensional continuum structures. The model developed for that purpose is extended here...... to cover the design of a structure and associated material properties for a system composed of a generic form of nonlinear softening material. As was established in the earlier study on design with linear materials, the formulation for combined 'material and structure' design with softening materials can...

  5. Studies on the role of polygalacturonase isoenzymes in tomato fruit softening and ripening

    OpenAIRE

    Harman, Jane Elizabeth

    1984-01-01

    Changes in the activity of polygalacturonase during the development and/or ripening of tomato fruit of a wide range of genotypes have been followed. Normal commercial cultivars have three forms of the enzyme; the isoenzyme having the highest molecular weight, PG1, appeared as fruit began to change colour, and its rate of accumulation was reflected in the rate of fruit softening.This early rate of softening was closely related to the eventual degree of softness shown by the fully ripe fruit.PG...

  6. Large elastic strain and elastocaloric effect caused by lattice softening in an iron-palladium alloy.

    Science.gov (United States)

    Kakeshita, Tomoyuki; Xiao, Fei; Fukuda, Takashi

    2016-08-13

    A Fe-31.2Pd (at.%) alloy exhibits a weak first-order martensitic transformation from a cubic structure to a tetragonal structure near 230 K. This transformation is associated with significant softening of elastic constant C'. Because of the softening, the alloy shows a large elastic strain of more than 6% in the [001] direction. In addition, the alloy has a critical point and shows a high elastocaloric effect in a wide temperature range for both the parent and the martensite phases.This article is part of the themed issue 'Taking the temperature of phase transitions in cool materials'.

  7. 40 CFR 141.553 - My system practices lime softening-is there any special provision regarding my combined filter...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false My system practices lime softening-is... Filter Effluent Requirements § 141.553 My system practices lime softening—is there any special provision regarding my combined filter effluent? If your system practices lime softening, you may...

  8. Two types of softening detected in X-ray afterglows of Swift bursts: internal and external shock origins?

    CERN Document Server

    Qin, Y -P; Fan, J H; Lu, R -J

    2008-01-01

    The softening process observed in the steep decay phase of early X-ray afterglows of Swift bursts has remained a puzzle since its discovery. The softening process can also be observed in the later phase of the bursts and its cause has also been unknown. Recently, it was suggested that, influenced by the curvature effect, emission from high latitudes would shift the Band function spectrum from higher energy band to lower band, and this would give rise to the observed softening process accompanied by a steep decay of the flux density. The curvature effect scenario predicts that the terminating time of the softening process would be correlated with the duration of the process. In this paper, based on the data from the UNLV GRB group web-site, we found an obvious correlation between the two quantities. In addition, we found that the softening process can be divided into two classes: the early type softening ($t_{s,max}\\leq "4000"s$) and the late type softening ($t_{s,max} > "4000"s$). The two types of softening s...

  9. Dehydration softening of serpentine and its roles in the intermediate-depth earthquakes

    Science.gov (United States)

    Shimizu, I.; Watanabe, Y.; Michibayashi, K.

    2010-12-01

    to pink, possibly due to highly oxidized atmosphere caused by free water release. Reaction products of olivine (forsterite) exhibited host-controlled weak lattice preferred orientation (LPO) but there was no evidence for intracrystalline slip. Mechanical behaviors and microstructural features both indicated that the dominant deformation mechanism of pre-heated samples was cataclastic flow of reaction products. Significant volume loss in these samples suggests compaction and escape of water during deformation experiments. Strain localization in the serpentinized parts of mantle due to dehydration softening and high fluid pressure caused by pore collapse would trigger earthquakes in surrounding peridotite mantle.

  10. Curvature Effect and the Spectral Softening Phenomenon Detected in GRB Afterglows

    Indian Academy of Sciences (India)

    Y.-P. Qin

    2011-03-01

    Detection of radiation from a relativistic fireball would be affected by the so-called curvature effect. I illustrate the expected temporal and spectral behaviours of this effect and show that it can well explain the observed spectral softening in the early GRB afterglows.

  11. Bacterial Colonization of Pellet Softening Reactors Used during Drinking Water Treatment

    NARCIS (Netherlands)

    Hammes, F.; Boon, N.; Vital, M.; Ross, P.; Magic-Knezev, A.; Dignum, M.

    2010-01-01

    Pellet softening reactors are used in centralized and decentralized drinking water treatment plants for the removal of calcium (hardness) through chemically induced precipitation of calcite. This is accomplished in fluidized pellet reactors, where a strong base is added to the influent to increase t

  12. Identification of Differentially Expressed Genes Associated with Apple Fruit Ripening and Softening by Suppression Subtractive Hybridization.

    Directory of Open Access Journals (Sweden)

    Zongying Zhang

    Full Text Available Apple is one of the most economically important horticultural fruit crops worldwide. It is critical to gain insights into fruit ripening and softening to improve apple fruit quality and extend shelf life. In this study, forward and reverse suppression subtractive hybridization libraries were generated from 'Taishanzaoxia' apple fruits sampled around the ethylene climacteric to isolate ripening- and softening-related genes. A set of 648 unigenes were derived from sequence alignment and cluster assembly of 918 expressed sequence tags. According to gene ontology functional classification, 390 out of 443 unigenes (88% were assigned to the biological process category, 356 unigenes (80% were classified in the molecular function category, and 381 unigenes (86% were allocated to the cellular component category. A total of 26 unigenes differentially expressed during fruit development period were analyzed by quantitative RT-PCR. These genes were involved in cell wall modification, anthocyanin biosynthesis, aroma production, stress response, metabolism, transcription, or were non-annotated. Some genes associated with cell wall modification, anthocyanin biosynthesis and aroma production were up-regulated and significantly correlated with ethylene production, suggesting that fruit texture, coloration and aroma may be regulated by ethylene in 'Taishanzaoxia'. Some of the identified unigenes associated with fruit ripening and softening have not been characterized in public databases. The results contribute to an improved characterization of changes in gene expression during apple fruit ripening and softening.

  13. Identification of Differentially Expressed Genes Associated with Apple Fruit Ripening and Softening by Suppression Subtractive Hybridization.

    Science.gov (United States)

    Zhang, Zongying; Jiang, Shenghui; Wang, Nan; Li, Min; Ji, Xiaohao; Sun, Shasha; Liu, Jingxuan; Wang, Deyun; Xu, Haifeng; Qi, Sumin; Wu, Shujing; Fei, Zhangjun; Feng, Shouqian; Chen, Xuesen

    2015-01-01

    Apple is one of the most economically important horticultural fruit crops worldwide. It is critical to gain insights into fruit ripening and softening to improve apple fruit quality and extend shelf life. In this study, forward and reverse suppression subtractive hybridization libraries were generated from 'Taishanzaoxia' apple fruits sampled around the ethylene climacteric to isolate ripening- and softening-related genes. A set of 648 unigenes were derived from sequence alignment and cluster assembly of 918 expressed sequence tags. According to gene ontology functional classification, 390 out of 443 unigenes (88%) were assigned to the biological process category, 356 unigenes (80%) were classified in the molecular function category, and 381 unigenes (86%) were allocated to the cellular component category. A total of 26 unigenes differentially expressed during fruit development period were analyzed by quantitative RT-PCR. These genes were involved in cell wall modification, anthocyanin biosynthesis, aroma production, stress response, metabolism, transcription, or were non-annotated. Some genes associated with cell wall modification, anthocyanin biosynthesis and aroma production were up-regulated and significantly correlated with ethylene production, suggesting that fruit texture, coloration and aroma may be regulated by ethylene in 'Taishanzaoxia'. Some of the identified unigenes associated with fruit ripening and softening have not been characterized in public databases. The results contribute to an improved characterization of changes in gene expression during apple fruit ripening and softening.

  14. ARSENIC REMOVAL FROM DRINKING WATER BY COAGULATION/FILTRATION AND LIME SOFTENING PLANTS

    Science.gov (United States)

    This report documents a long term performance (one year) study of 3 water treatment plants to remove arsenic from drinking water sources. The 3 plants consisted of 2 conventional coagulation/filtration plants and 1 lime softening plant. The study involved the collecting of weekly...

  15. Evaluation of the impact of lime softening waste disposal in natural environments

    Science.gov (United States)

    Drinking water treatment residues (WTR), generated from the lime softening processes, are commonly reused or disposed of in a number of applications; these include use as a soil amendment or a subsurface fill. Recently questions were posed by the Florida regulatory community on w...

  16. The Value of Fighting Irreversible Demise by Softening the Irreversible Cost

    NARCIS (Netherlands)

    Magis, P.; Sbuelz, A.

    2005-01-01

    We study a novel issue in the real-options-based technology innovation literature by means of double barrier contingent claims analysis.We show how much a ¯rm with the monopoly over a project is willing to spend in investment technology innovation that softens the irreversible cost of accessing the

  17. Influence of Amino-Ffunctional Macro and Micro Silicone Softeners on the Properties of Cotton Fabric

    Directory of Open Access Journals (Sweden)

    Abdul Wahab Jatoi

    2015-01-01

    Full Text Available Amino-functional silicone softeners are most widely used type of soft finishes owing to their outstanding permanent softness, smoothness and handle characteristics. These soft finishes are prepared in different emulsion droplet sizes such as macro and micro emulsions providing varying characteristics on the textile on which they are applied. The macroemulsions due to their larger droplet sizes lubricate fabric and yarn surfaces, while the micro-emulsion, thanks to their smaller sizes penetrate inside fiber pores. In this research amino-functional macro and micro emulsions have been applied on dyed cotton fabric in 1:1 combination and compared against their influence on physical properties such as bending length, abrasion resistance, tensile strength, crease resistance and water repellency. These emulsions have also been compared for their influence on colorimetric properties; color difference and color strength (K/S values. The results reveal that the softener`s application in combination improves the properties deteriorated by each softener when applied separately

  18. Effects of preoxidation on the swelling and softening of bituminous coals

    Energy Technology Data Exchange (ETDEWEB)

    Maloney, D. J.; Jenkins, R. G.; Walker, Jr., P. L.

    1980-04-01

    A study was conducted to evaluate the applicability of a DuPont 942-TMA (Thermomechanical Analyzer) dilatometer system for the characterization of the swelling and softening properties of caking coals. The results of this investigation demonstrate the utility of this dilatometer system. Several parameters clearly defined with this unit are characteristic of the plastic transitions occurring upon carbonization. These include softening, dilation and resolidification temperature and volume contraction, expansion and total dilation values. The transition parameters measured with the 942-TMA unit are influenced significantly by coal particle size, dilatometer load, and heating rate. All transition temperatures exhibit marked increases with increasing heating rate. Softening temperatures decrease with increasing load and particle size. Dilation temperatures are essentially independent of dilatometer load effects and resolidification temperatures are independent of load and particle size over the range of conditions used in this study. Volume contraction and expansion values show an increase with decreasing coal particle size. Volume expansion values also exhibit strong heating rate and load dependencies. The results point up the great difficulty involved in obtaining truly fresh unoxidized coal samples. Storage of fine coal particles for extended periods of time in atmospheres with even slight oxygen concentrations show signs of weathering. Exposure of an HVA coal to dry air at ambient temperature has much less effect on subsequent swelling and softening properties than does exposure to moist air.

  19. Advanced Chemical Precipitation Softening. Training Module 2.217.4.77.

    Science.gov (United States)

    McMullen, L. D.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with the operation and maintenance of a chemical precipitation softening system. Included are objectives, instructor guides, student handouts and transparency masters. This is the third level of a three module series. This module considers…

  20. Basic Chemical Precipitation Softening. Training Module 2.215.2.77.

    Science.gov (United States)

    McMullen, L. D.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with chemical precipitation softening. Included are objectives, an instructor guide, student handouts and transparency masters. This is the first level of a three module series and is designed for students with little or no operating…

  1. Reversible stress softening in layered rat esophagus in vitro after potassium chloride activation.

    Science.gov (United States)

    Jiang, Hongbo; Liao, Donghua; Zhao, Jingbo; Wang, Guixue; Gregersen, Hans

    2017-01-23

    Significant stress softening recovery after potassium chloride (KCl) administration was previously demonstrated in the intact rat esophageal wall. The aim of this study is to investigate the effect of KCl activation on stress softening recovery in the separated mucosa-submucosa layer and muscle layer of rat esophagus. Three series of loading-unloading distensions were carried out on 10 rat esophagi where the two separated layers were distended at luminal pressure levels 0.5, 1.0 and 2.0 kPa. Numerous distension cycles were done in [Formula: see text]-free Krebs solution before and after activation with KCl (110 mmol) for 3 min in calcium-containing media. The diameter and luminal pressure were recorded for stress and strain calculation. During KCl activation, the muscle layer responded with a high-amplitude contraction, and the mucosa-submucosa layer responded with a longer-lasting low-amplitude contraction. The hysteresis loop areas from the muscle layer were significantly bigger than those from the mucosa-submucosa layer at distension pressures 1.0 and 2.0 kPa ([Formula: see text]). The calculated stiffness in the mucosa-submucosa layer was significantly higher than that in the muscle layer ([Formula: see text]). After activation with KCl, the stored energy and the stiffness after the stress and viscoelasticity softening increased in both layers, indicating that the reversible stress softening in esophagus after KCl activation is existed in both layers.

  2. Haz-Map Glossary

    Science.gov (United States)

    ... for new molecules. Subsequent addition of in vivo test results (e.g., mouse micronucleus) to the battery database failed to improve its ... for new molecules. Subsequent addition of in vivo test results (e.g., mouse micronucleus) to the battery database failed to improve its ...

  3. Development and deployment of constitutive softening routines in Eulerian hydrocodes.

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, Timothy Jesse; Dewers, Thomas A.; Swan, Matthew Scot

    2013-03-01

    The state of the art in failure modeling enables assessment of crack nucleation, propagation, and progression to fragmentation due to high velocity impact. Vulnerability assessments suggest a need to track material behavior through failure, to the point of fragmentation and beyond. This eld of research is particularly challenging for structures made of porous quasi-brittle materials, such as ceramics used in modern armor systems, due to the complex material response when loading exceeds the quasi-brittle material's elastic limit. Further complications arise when incorporating the quasi-brittle material response in multi-material Eulerian hydrocode simulations. In this report, recent e orts in coupling a ceramic materials response in the post-failure regime with an Eulerian hydro code are described. Material behavior is modeled by the Kayenta material model [2] and Alegra as the host nite element code [14]. Kayenta, a three invariant phenomenological plasticity model originally developed for modeling the stress response of geologic materials, has in recent years been used with some success in the modeling of ceramic and other quasi-brittle materials to high velocity impact. Due to the granular nature of ceramic materials, Kayenta allows for signi cant pressures to develop due to dilatant plastic ow, even in shear dominated loading where traditional equations of state predict little or no pressure response. When a material's ability to carry further load is compromised, Kayenta allows the material's strength and sti ness to progressively degrade through the evolution of damage to the point of material failure. As material dilatation and damage progress, accommodations are made within Alegra to treat in a consistent manner the evolving state.

  4. ELASTO-PLASTIC CONSTITUTIVE MODEL OF SOIL-STRUCTURE INTERFACE IN CONSIDERATION OF STRAIN SOFTENING AND DILATION

    Institute of Scientific and Technical Information of China (English)

    Aizhao Zhou; Tinghao Lu

    2009-01-01

    The behavior of soil-structure interface plays a major role in the definition of soil-structure interaction. In this paper a bi-potential surface elasto-plastic model for soil-structure interface is proposed in order to describe the interface deformation behavior, including strain softening and normal dilatancy. The model is formulated in the framework of generalized potential theory, in which the soil-structure interface problem is regard as a two-dimensional mathematical problem in stress field, and plastic state equations are used to replace the traditional field surface. The relation curves of shear stress and tangential strain are fitted by a piecewise function composed by hyperbolic functions and hyperbolic secant functions, while the relation curves of normal strain and tangential strain are fitted by another piecewise function composed by quadratic functions and hyperbolic secant functions. The approach proposed has the advantage of deriving an elasto-plastic constitutive matrix without postulating the plastic potential functions and yield surface. Moreover, the mathematical principle is clear, and the entire model parameters can be identified by experimental tests. Finally, the predictions of the model have been compared with experimental results obtained from simple shear tests under normal stresses, and results show the model is reasonable and practical.

  5. Lower Greenschist Facies Oscillations Across the Brittle-Ductile Transition Induced by Alternating Reaction Softening and Hardening Events

    Science.gov (United States)

    Wintsch, R. P.; Yeh, M.

    2011-12-01

    contiguous bands constituting textural softening (Shea and Kronenberg, 1993). These reactions occur without any demonstrable change in temperature, and so produce a shift from brittle to ductile behavior. The reactions also involve a volume loss, such that they will be driven by a high normal stress; thus they are readily driven by a high normal stress. These ductile fabrics are in turn cut by K-feldspar veins that interrupt the mylonitic fabric produced by the above reactions. The K-feldspar veins add K-feldspar to the assemblage and interrupt the mylonitic fabric. Thus these structures constitute both reaction and textural hardening. Finally these may become boudinaged by continued ductile deformation in the mylonitic matrix, thus establishing a late ductile strain event. Together these overprinting textures and microstructures demonstrate two oscillations of brittle to ductile deformation all at lower greenschist facies conditions where only frictional behavior is predicted by experiments.

  6. Shear softening of Earth's inner core indicated by its high Poisson's ratio and elastic anisotropy

    CERN Document Server

    Wu, Zhongqing

    2016-01-01

    Earth's inner core exhibits an unusually high Poisson's ratio and noticeable elastic anisotropy. The mechanisms responsible for these features are critical for understanding the evolution of the Earth but remain unclear. This study indicates that once the correct formula for the shear modulus is used, shear softening can simultaneously explain the high Poisson's ratio and strong anisotropy of the inner core. Body-centred-cubic (bcc) iron shows shear instability at the pressures found in the inner-core and can be dynamically stabilized by temperature and light elements. It is very likely that some combinations of light elements stabilize the bcc iron alloy under inner-core conditions. Such a bcc phase would exhibit significant shear softening and match the geophysical constraints of the inner core. Identifying which light elements and what concentrations of these elements stabilize the bcc phase will provide critical information on the light elements of the inner core.

  7. Acoustic softening in metals during ultrasonic assisted deformation via CP-FEM

    KAUST Repository

    Siddiq, Amir

    2011-01-01

    In this paper, a phenomenological crystal plasticity model is modified to account for acoustic (ultrasonic) softening effects based on the level of ultrasonic intensity supplied to single and polycrystalline metals. The material parameters are identified using the inverse modeling approach by interfacing the crystal plasticity model with an optimization tool. The proposed model is validated and verified by comparing the microstructure evolution with experimental EBSD results reported in the literature. The model is able to capture the ultrasonic softening effect and the results show that as the ultrasonic intensity increases, the plastic deformation also increases. Differences in the stress-strain response are explained based on the slip system orientation tensor (Schmidt factors) which depends upon the crystal orientation. © 2010 Elsevier B.V. All rights reserved.

  8. INVESTIGATION OF SOFTENING AGENT PREPARATION AND PERFORMANCE OF HANDMADE ECOCOMPOSITES WITH CONIFEROUS WOOD AND BASALT FIBERS

    Institute of Scientific and Technical Information of China (English)

    GuangjianWang; DekuShang; KailiangZhang; LinnaHu; ZhenhuaGuo

    2004-01-01

    In this investigation, basalt mineral fiber softening agent was prepared in order to obtain desirable flexible performance. Stability and physical chemistry natures of softening agent were evaluated by particle size distribution, dilution, storage and folding endurance etc. Constitutes of basalt and wood fibers were determined by energy dispersion analysis X-ray which served as an accessory of scanning electron microscopy (SEM-EDAX). Naturally degradable ecocomposite was prepared by basalt and wood fibers. The results of SEM observation illustrated that the wood and basalt fibers were blended uniformly. The impact factors of beating degree, content of wood fibers and adhesive etc. were discussed. The structure of the naturally degradable ecocomposite was contrasted with that of pure wood fibers and the cause of excellent filtration performance was analyzed. Compared with traditional methods, it was of saving wood resource, a large amount of water and reducing second pollution. As a consequence, the ecocomposite harmonized with environment and accorded with requirement of benignly friendly environment.

  9. The importance of structural softening for the evolution and architecture of passive margins

    Science.gov (United States)

    Duretz, T.; Petri, B.; Mohn, G.; Schmalholz, S. M.; Schenker, F. L.; Müntener, O.

    2016-12-01

    Lithospheric extension can generate passive margins that bound oceans worldwide. Detailed geological and geophysical studies in present and fossil passive margins have highlighted the complexity of their architecture and their multi-stage deformation history. Previous modeling studies have shown the significant impact of coarse mechanical layering of the lithosphere (2 to 4 layer crust and mantle) on passive margin formation. We built upon these studies and design high-resolution (~100–300 m) thermo-mechanical numerical models that incorporate finer mechanical layering (kilometer scale) mimicking tectonically inherited heterogeneities. During lithospheric extension a variety of extensional structures arises naturally due to (1) structural softening caused by necking of mechanically strong layers and (2) the establishment of a network of weak layers across the deforming multi-layered lithosphere. We argue that structural softening in a multi-layered lithosphere is the main cause for the observed multi-stage evolution and architecture of magma-poor passive margins.

  10. Influence of curing rate on softening in ethanol, degree of conversion, and wear of resin composite

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Peutzfeldt, Anne; Asmussen, Erik

    2011-01-01

    PURPOSE: To investigate the effect of curing rate on softening in ethanol, degree of conversion, and wear of resin composites. METHOD: With a given energy density and for each of two different light-curing units (QTH or LED), the curing rate was reduced by modulating the curing mode. Thus......, the irradiation of resin composite specimens (Filtek Z250, Tetric Ceram, Esthet-X) was performed in a continuous curing mode and in a pulse-delay curing mode. Wallace hardness was used to determine the softening of resin composite after storage in ethanol. Degree of conversion was determined by infrared...... spectroscopy (FTIR). Wear was assessed by a three-body test. Data were submitted to Levene's test, one and three-way ANOVA, and Tukey HSD test (alpha = 0.05). Results: Immersion in ethanol, curing mode, and material all had significant effects on Wallace hardness. After ethanol storage, resin composites...

  11. Particle Surface Softening as Universal Behaviour during Flash Sintering of Oxide Nano-Powders

    Directory of Open Access Journals (Sweden)

    Rachman Chaim

    2017-02-01

    Full Text Available The dissipated electric power in oxide powder compacts, subjected to flash sintering, is several hundreds of W·cm−3. This power is analyzed considering local softening/melting and transient plasma/liquid formation at the particle contacts due to thermal runaway. The sudden increase in compact electric conductivity and dissipated power referred to current percolation through the softening/liquid formed at the particle contacts, at the percolation threshold. The energy-balance and heat transfer considerations during the transient flash event are consistent with the local heating of the nanoparticle contacts to the ceramic melting temperature, or above it. The formation of the plasma by field emission of electrons is also considered.

  12. Pectin modifications and the role of pectin-degrading enzymes during postharvest softening of Jonagold apples.

    Science.gov (United States)

    Gwanpua, Sunny George; Van Buggenhout, Sandy; Verlinden, Bert E; Christiaens, Stefanie; Shpigelman, Avi; Vicent, Victor; Kermani, Zahra Jamsazzadeh; Nicolai, Bart M; Hendrickx, Marc; Geeraerd, Annemie

    2014-09-01

    This study aimed at understanding softening in Jonagold apple (Malus×domestica Borkh.) fruits, by investigating pectin modifications and the evolution of pectin-modifying enzymes during postharvest storage and ripening. Jonagold apples were harvested at commercial maturity and stored at different temperatures and controlled atmosphere conditions for 6 months, followed by exposure to ambient shelf life conditions (20 °C under air) for 2 weeks. The composition of the pectic material was analysed. Furthermore, the firmness and the ethylene production of the apples were assessed. Generally, the main changes in pectin composition associated with the loss of firmness during ripening in Jonagold apples were a loss of side chains neutral sugars, increased water solubility and decreased molar mass. Also, the activities of four important enzymes possibly involved in apple softening, β-galactosidase, α-arabinofuranosidase, polygalacturonase and pectin methylesterase, were measured. Pectin-related enzyme activities highly correlated with ethylene production, but not always with pectin modifications.

  13. Softening of monthly cigarette use in youth and the need to harden measures in surveillance

    Directory of Open Access Journals (Sweden)

    Lynn T. Kozlowski

    2014-01-01

    Conclusion: Additional measures of frequency and intensity of use of cigarettes and other tobacco/nicotine products need to be more regularly reported. These results indicate softening rather than hardening of “current smoking” and have important implications for tobacco surveillance and for tobacco research because of a increased likelihood of quitting smoking, b health effects of cigarette smoking, and c similar and interacting issues related to measuring the use of all tobacco/nicotine products.

  14. Technological Process and Equipment for Electric-local Softening Soil of Different Strength and Structure

    Directory of Open Access Journals (Sweden)

    Rizun, A.R.

    2014-09-01

    Full Text Available Electric-discharge technology for soil local softening is developed; the pre-production model of mobile high-energy electric-discharge generator with the controlled energy release is produced. Application of the proposed equipment and technology will allow essentially reduce construction materials and cost of the installation and construction works, in particular, capital investments in alternative energy, industrial, residential construction, and hydraulic engineering in general.

  15. Application of fractal dimensions to study the structure of flocs formed in lime softening process.

    Science.gov (United States)

    Vahedi, Arman; Gorczyca, Beata

    2011-01-01

    The use of fractal dimensions to study the internal structure and settling of flocs formed in lime softening process was investigated. Fractal dimensions of flocs were measured directly on floc images and indirectly from their settling velocity. An optical microscope with a motorized stage was used to measure the fractal dimensions of lime softening flocs directly on their images in 2 and 3D space. The directly determined fractal dimensions of the lime softening flocs were 1.11-1.25 for floc boundary, 1.82-1.99 for cross-sectional area and 2.6-2.99 for floc volume. The fractal dimension determined indirectly from the flocs settling rates was 1.87 that was different from the 3D fractal dimension determined directly on floc images. This discrepancy is due to the following incorrect assumptions used for fractal dimensions determined from floc settling rates: linear relationship between square settling velocity and floc size (Stokes' Law), Euclidean relationship between floc size and volume, constant fractal dimensions and one primary particle size describing entire population of flocs. Floc settling model incorporating variable floc fractal dimensions as well as variable primary particle size was found to describe the settling velocity of large (>50 μm) lime softening flocs better than Stokes' Law. Settling velocities of smaller flocs (lime floc size in this study indicated that two mechanisms are involved in the formation of these flocs: cluster-cluster aggregation for small flocs (50 μm). Therefore, the relationship between the floc fractal dimension and floc size appears to be determined by floc formation mechanisms.

  16. Proteomic analysis of peach fruit mesocarp softening and chilling injury using difference gel electrophoresis (DIGE

    Directory of Open Access Journals (Sweden)

    Campos-Vargas Reinaldo

    2010-01-01

    Full Text Available Abstract Background Peach fruit undergoes a rapid softening process that involves a number of metabolic changes. Storing fruit at low temperatures has been widely used to extend its postharvest life. However, this leads to undesired changes, such as mealiness and browning, which affect the quality of the fruit. In this study, a 2-D DIGE approach was designed to screen for differentially accumulated proteins in peach fruit during normal softening as well as under conditions that led to fruit chilling injury. Results The analysis allowed us to identify 43 spots -representing about 18% of the total number analyzed- that show statistically significant changes. Thirty-nine of the proteins could be identified by mass spectrometry. Some of the proteins that changed during postharvest had been related to peach fruit ripening and cold stress in the past. However, we identified other proteins that had not been linked to these processes. A graphical display of the relationship between the differentially accumulated proteins was obtained using pairwise average-linkage cluster analysis and principal component analysis. Proteins such as endopolygalacturonase, catalase, NADP-dependent isocitrate dehydrogenase, pectin methylesterase and dehydrins were found to be very important for distinguishing between healthy and chill injured fruit. A categorization of the differentially accumulated proteins was performed using Gene Ontology annotation. The results showed that the 'response to stress', 'cellular homeostasis', 'metabolism of carbohydrates' and 'amino acid metabolism' biological processes were affected the most during the postharvest. Conclusions Using a comparative proteomic approach with 2-D DIGE allowed us to identify proteins that showed stage-specific changes in their accumulation pattern. Several proteins that are related to response to stress, cellular homeostasis, cellular component organization and carbohydrate metabolism were detected as being

  17. Identification of Strain-Softening Properties and Computational Predictions of Localized Fracture.

    Science.gov (United States)

    1984-03-01

    OFFICE SYMBOL I de .4 a Code) LAWRENCE D. HOKANSON, Lt. Col. USAF (202) 767-4935 AFOSR/NA DO FORM 1473, 83 APR EDITION OF I JAN 73 IS OBSOLETE...crack band approach of Bazant and co-wor- kers [9] who interpreted the fictitious crack model of Hillerborg et al [10] within a crack band of finite...shear bands within linear bifurcation studies [13], [14]. In fact, Bazant offered some elementary strain-softening interpretation of concrete in

  18. Proteomic analysis of peach fruit mesocarp softening and chilling injury using difference gel electrophoresis (DIGE).

    Science.gov (United States)

    Nilo, Ricardo; Saffie, Carlos; Lilley, Kathryn; Baeza-Yates, Ricardo; Cambiazo, Verónica; Campos-Vargas, Reinaldo; González, Mauricio; Meisel, Lee A; Retamales, Julio; Silva, Herman; Orellana, Ariel

    2010-01-18

    Peach fruit undergoes a rapid softening process that involves a number of metabolic changes. Storing fruit at low temperatures has been widely used to extend its postharvest life. However, this leads to undesired changes, such as mealiness and browning, which affect the quality of the fruit. In this study, a 2-D DIGE approach was designed to screen for differentially accumulated proteins in peach fruit during normal softening as well as under conditions that led to fruit chilling injury. The analysis allowed us to identify 43 spots -representing about 18% of the total number analyzed- that show statistically significant changes. Thirty-nine of the proteins could be identified by mass spectrometry. Some of the proteins that changed during postharvest had been related to peach fruit ripening and cold stress in the past. However, we identified other proteins that had not been linked to these processes. A graphical display of the relationship between the differentially accumulated proteins was obtained using pairwise average-linkage cluster analysis and principal component analysis. Proteins such as endopolygalacturonase, catalase, NADP-dependent isocitrate dehydrogenase, pectin methylesterase and dehydrins were found to be very important for distinguishing between healthy and chill injured fruit. A categorization of the differentially accumulated proteins was performed using Gene Ontology annotation. The results showed that the 'response to stress', 'cellular homeostasis', 'metabolism of carbohydrates' and 'amino acid metabolism' biological processes were affected the most during the postharvest. Using a comparative proteomic approach with 2-D DIGE allowed us to identify proteins that showed stage-specific changes in their accumulation pattern. Several proteins that are related to response to stress, cellular homeostasis, cellular component organization and carbohydrate metabolism were detected as being differentially accumulated. Finally, a significant proportion of

  19. Lipídios estruturados obtidos a partir da mistura de gordura de frango, sua estearina e triacilgliceróis de cadeia média: II- pontos de amolecimento e fusão Structured lipids from chicken fat, its stearin, and medium chain triacyglycerol blends: II- softening and melting points

    Directory of Open Access Journals (Sweden)

    Ming Chih Chiu

    2008-01-01

    Full Text Available The aim of the present work is to investigate the effects of blending and chemical interesterification reactions on the softening and melting behavior of chicken fat, its stearin and medium chain triacylglycerols, and blends thereof in various ratios. Chemical interesterification is a promising alternative to the current processes of modifying the physical properties of fats. In the experimental design 7 samples corresponding to 7 different blend proportions were used. The results were represented in triangular diagrams. The addition of stearin influenced the softening and melting points. The mixture response surface methodology proved to be an extremely useful tool for the optimization of the fat mixtures.

  20. Induced mutations in tomato SlExp1 alter cell wall metabolism and delay fruit softening.

    Science.gov (United States)

    Minoia, Silvia; Boualem, Adnane; Marcel, Fabien; Troadec, Christelle; Quemener, Bernard; Cellini, Francesco; Petrozza, Angelo; Vigouroux, Jacqueline; Lahaye, Marc; Carriero, Filomena; Bendahmane, Abdelhafid

    2016-01-01

    Fruit ripening and softening are key traits for many fleshy fruit. Since cell walls play a key role in the softening process, expansins have been investigated to control fruit over ripening and deterioration. In tomato, expression of Expansin 1 gene, SlExp1, during fruit ripening was associated with fruit softening. To engineer tomato plants with long shelf life, we screened for mutant plants impaired in SlExp1 function. Characterization of two induced mutations, Slexp1-6_W211S, and Slexp1-7_Q213Stop, showed that SlExp1 loss of function leads to enhanced fruit firmness and delayed fruit ripening. Analysis of cell wall polysaccharide composition of Slexp1-7_Q213Stop mutant pointed out significant differences for uronic acid, neutral sugar and total sugar contents. Hemicelluloses chemistry analysis by endo-β-1,4-d-glucanase hydrolysis and MALDI-TOF spectrometry revealed that xyloglucan structures were affected in the fruit pericarp of Slexp1-7_Q213Stop mutant. Altogether, these results demonstrated that SlExp1 loss of function mutants yield firmer and late ripening fruits through modification of hemicellulose structure. These SlExp1 mutants represent good tools for breeding long shelf life tomato lines with contrasted fruit texture as well as for the understanding of the cell wall polysaccharide assembly dynamics in fleshy fruits.

  1. Softening and Hardening of a Micro-electro-mechanical systems (MEMS) Oscillator in a Nonlinear Regime

    Science.gov (United States)

    Johnson, Sarah; Edmonds, Terrence

    Micro-electro-mechanical systems or MEMS are used in a variety of today's technology and can be modeled using equations for nonlinear damped harmonic oscillators. Mathematical expressions have been formulated to determine resonance frequency shifts as a result of hardening and softening effects in MEMS devices. In this work we experimentally test the previous theoretical analysis of MEMS resonance frequency shifts in the nonlinear regime. Devices were put under low pressure at room temperature and swept through a range of frequencies with varying AC and DC excitation voltages to detect shifts in the resonant frequency. The MEMS device studied in this work exhibits a dominating spring softening effect due to the device's physical make-up. The softening effect becomes very dominant as the AC excitation is increased and the frequency shift of the resonance peak becomes quite significant at these larger excitations. Hardening effects are heavily dependent on mechanical factors that make up the MEMS devices. But they are not present in these MEMS devices. I will present our results along with the theoretical analysis of the Duffing oscillator model. This work was supported by NSF grant DMR-1461019 (REU) and DMR-1205891 (YL).

  2. Salivary a-amylase protects enamel surface against acid induced softening

    DEFF Research Database (Denmark)

    Lazovic, Maja Bruvo; Moe, Dennis; Kirkeby, Svend

    Objectives: Recently we have demonstrated individual differences in protection against acid-induced enamel softening offered by experimentally developed saliva pellicles. Although ethnicity seemed to be related to protection level, the saliva proteins responsible for the differences were not iden......Objectives: Recently we have demonstrated individual differences in protection against acid-induced enamel softening offered by experimentally developed saliva pellicles. Although ethnicity seemed to be related to protection level, the saliva proteins responsible for the differences were......, and one Chinese. After collection, saliva was dialysed and lyophilised and re-dissolved at 0.5% in Type I water. Next, four polished bovine enamel specimens were immersed into each sample under gentle and constant shaking for 12 hours. Last, specimens were exposed to an erosive challenge of pH 2.3 for 4......-TOF mass fingerprinting following trypsin digestion. Each persistent peak in the HPLC chromatograms was related to the protective effect against acid-induced enamel softening obtained by the corresponding saliva sample by multiple regression analysis. Results: One peak identified as a-amylase had...

  3. Using fabric softeners, drying and ironing in Germany. A non-representative census of consumer behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Braun, Verena; Stamminger, Rainer [Bonn Univ. (Germany). Household and Appliance Technology Section

    2011-05-15

    During the annually arranged Action Day Sustainable Washing on May 10{sup th}, 5284 questionnaires about laundry treatment were collected from private people in Germany with the aim of obtaining information about consumer behaviour and attitudes towards sustainability. This is a non-representative census as only 15% of all respondents were male. Nevertheless, relative distribution and correlation provide a relevant insight into consumers' behaviour towards washing, drying and ironing. The most important results of the analysis can be summed up as follows: - Nearly 50% of the respondents own a laundry-dryer. - Nearly one third of all respondents never use fabric softeners. The prevention of ecological damage was the reason for not using fabric softeners for 30% of the respondents. - About one fourth of all respondents always use fabric softeners, with younger people having a significantly higher attitude towards using them. - Under good weather conditions, about 90% of the respondents choose energy-saving alternatives to dry their laundry. - The average weekly time spent on ironing is about two hours on average of all respondents who gave information. The analysis shows that laundry treatment beyond the pure washing process is a multi-faceted process with several starting points of improvement in favour of sustainable handling. (orig.)

  4. Electrochemical Ion-Exchange Regeneration and Fluidized Bed Crystallization for Zero-Liquid-Discharge Water Softening.

    Science.gov (United States)

    Chen, Yingying; Davis, Jake R; Nguyen, Chi H; Baygents, James C; Farrell, James

    2016-06-01

    This research investigated the use of an electrochemical system for regenerating ion-exchange media and for promoting the crystallization of hardness minerals in a fluidized bed crystallization reactor (FBCR). The closed-loop process eliminates the creation of waste brine solutions that are normally produced when regenerating ion-exchange media. A bipolar membrane electrodialysis stack was used to generate acids and bases from 100 mM salt solutions. The acid was used to regenerate weak acid cation (WAC) ion-exchange media used for water softening. The base solutions were used to absorb CO2 gas and to provide a source of alkalinity for removing noncarbonate hardness by WAC media operated in H(+) form. The base solutions were also used to promote the crystallization of CaCO3 and Mg(OH)2 in a FBCR. The overall process removes hardness ions from the water being softened and replaces them with H(+) ions, slightly decreasing the pH value of the softened water. The current utilization efficiency for acid and base production was ∼75% over the operational range of interest, and the energy costs for producing acids and bases were an order of magnitude lower than the costs for purchasing acid and base in bulk quantities. Ion balances indicate that the closed-loop system will accumulate SO4(2-), Cl(-), and alkali metal ions. Acid and base balances indicate that for a typical water, small amounts of base will be accumulated.

  5. Effect of nitric oxide on ethylene synthesis and softening of banana fruit slice during ripening.

    Science.gov (United States)

    Cheng, Guiping; Yang, En; Lu, Wangjin; Jia, Yongxia; Jiang, Yueming; Duan, Xuewu

    2009-07-08

    The effects of nitric oxide (NO) on ethylene synthesis and softening of ripening-initiated banana slice were investigated. Fruit firmness, color, and contents of starch and acid-soluble pectin (ASP) were measured. In addition, ethylene production, 1-aminocyclopropane-1-carboxylic acid (ACC) content, expression and activities of ACC synthase (ACS) and ACC oxidase (ACO), and activities of cell-wall-modifying enzymes, polygalacturonase (PG), pectin methylesterase (PME), and endo-beta-1,4-glucanase, were analyzed. Application of NO reduced ethylene production, inhibited degreening of the peel and delayed softening of the pulp. The decrease of ethylene production was associated with the reduction in the activity of ACO and the expression of the MA-ACO1 gene. Moreover, the NO-treated fruit showed a lower expression of the MA-ACS1 gene but higher ACS activity and ACC content. In addition, NO treatment decreased the activities of PG, PME, and endo-beta-1,4-glucanase and maintained higher contents of ASP and starch, which may account for the delay of softening. We proposed that the inhibition of ACO activity and transcription of gene MA-ACO1 by NO resulted in decreased ethylene synthesis and the delay of ripening of banana slice.

  6. Surfactant softening of plant leaf cuticle model wax--a Differential Scanning Calorimetry (DSC) and Quartz Crystal Microbalance with Dissipation (QCM-D) study.

    Science.gov (United States)

    Fagerström, Anton; Kocherbitov, Vitaly; Westbye, Peter; Bergström, Karin; Arnebrant, Thomas; Engblom, Johan

    2014-07-15

    The aim was to quantify the softening effect that two surfactants (C10EO7 and C8G1.6) have on a plant leaf cuticle model wax. Effects on the thermotropic phase behavior and fluidity of the wax (C22H45OH/C32H66/H2O) were determined. The model wax is crystalline at ambient conditions, yet it is clearly softened by the surfactants. Both surfactants decreased the transition temperatures in the wax and the G″/G' ratio of the wax film increased in irreversible steps following surfactant exposure. C10EO7 has a stronger fluidizing effect than C8G1.6 due to stronger interaction with the hydrophobic waxes. Intracuticular waxes (IW) comprise both crystalline and amorphous domains and it has previously been proposed that the fluidizing effects of surfactants are due to interactions with the amorphous parts. New data suggests that this may be a simplification. Surfactants may also absorb in crevices between crystalline domains. This causes an irreversible effect and a softer cuticle wax.

  7. Analysis of Papaya Cell Wall-Related Genes during Fruit Ripening Indicates a Central Role of Polygalacturonases during Pulp Softening

    Science.gov (United States)

    Fabi, João Paulo; Broetto, Sabrina Garcia; da Silva, Sarah Lígia Garcia Leme; Zhong, Silin; Lajolo, Franco Maria; do Nascimento, João Roberto Oliveira

    2014-01-01

    Papaya (Carica papaya L.) is a climacteric fleshy fruit that undergoes dramatic changes during ripening, most noticeably a severe pulp softening. However, little is known regarding the genetics of the cell wall metabolism in papayas. The present work describes the identification and characterization of genes related to pulp softening. We used gene expression profiling to analyze the correlations and co-expression networks of cell wall-related genes, and the results suggest that papaya pulp softening is accomplished by the interactions of multiple glycoside hydrolases. The polygalacturonase cpPG1 appeared to play a central role in the network and was further studied. The transient expression of cpPG1 in papaya results in pulp softening and leaf necrosis in the absence of ethylene action and confirms its role in papaya fruit ripening. PMID:25162506

  8. Investigation of work softening mechanisms and texture in a hot deformed 6061 aluminum alloy at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ezatpour, H.R., E-mail: H.R.Ezatpour@gmail.com [Department of Materials Science and Metallurgical Engineering, Engineering Faculty, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Haddad Sabzevar, M.; Sajjadi, S.A. [Department of Materials Science and Metallurgical Engineering, Engineering Faculty, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Huang, Yz., E-mail: yzhuang@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2014-06-01

    Hot deformation behavior of 6061 aluminum alloy was investigated by performing compression test in the temperature range of 350–500 °C. Equivalent strain rates were selected in the range of 0.0005–0.5 s{sup −1} in order to obtain processing and stability maps of the studied material using a Dynamic Material Model. Microstructure of the samples after deformation was analyzed by light and electron microscopy and the differences were compared together. The stresses obtained from the flow curves were related to strain rate (ε) and temperature (T) by a constitutive equation in hyperbolic sine function with hot deformation activation energy of 274 kJ/mol, and were described by the Zener–Hollomon equation. Microstructure results showed that with decreasing Z value, the elongated grains coarsened and the tendency of dynamic recrystallization enhanced. Correspondingly, the subgrain size increased and the dislocation density decreased. Moreover, the main softening mechanism of the alloy transformed from dynamic recovery to dynamic recrystallization. XRD results showed that the (200) texture has an important role in development of dynamic recystallization at high temperature.

  9. Softening and Mineral Content of Cassava (Manihot esculenta Crantz) Leaves During the Fermentation to Produce Ntoba mbodi

    OpenAIRE

    S. Mokemiabeka; J. Dhellot; S.C. Kobawila; P. Diakabana; R.N. Ntietie Loukombo; A.G. Nyanga-Koumou; D. Louembe

    2011-01-01

    The aim of study is to investigate the softening of cassava leaves during the fermentation of Ntoba mbodi and the mineral content of cassava leaves fermented and unfermented. The softening of cassava leaves is a characteristic of fermentation to produce Ntoba mbodi. It is due to an enzymatic process. The activity of cellulase and polygalacturonase enzymes, very weak at the beginning of fermentation, increases sharply in 24 h and decreases thereafter. The pectinesterase and pectin lyase activi...

  10. Behaviorism

    National Research Council Canada - National Science Library

    Moore, J

    2011-01-01

    .... Watson proposed an alternative: classical S-R behaviorism. According to Watson, behavior was a subject matter in its own right, to be studied by the observational methods common to all sciences...

  11. Bazı Simpatomimetik Aminlerin 2,4-Dinitrobenzensülfenil Türevleri I: Türevlerin hazırlanması ve karakter ize edilmesi

    OpenAIRE

    ., Rasim TULUS ve Lale ZEYTİNOĞLU

    2013-01-01

    Serbest bazı eterli çözeltide 2,4-dinitrobenzensülfenil klorürle re­aksiyona sokmak suretiyle 6 simpatomimetik aminin (amfetamin, me-tamfetamin, efedrin, metoksifenamin, mefentermin ve siklopentamin) N-2,4-dinitrobenzensülfenil türevi (Si-Sg) hazırlandı. Sarı renkli olan bu türevler elementel analiz, Rast usulü ile molekül vezni tayini, tita-nometrik titrasyonla ekivalan vezni tayini, erime noktası, çözünürlük­lerinin tayini suretiyle karakterize edildi. Efedrin türevinde 2,4-dinit­robenzensü...

  12. 铁素体不锈钢CMT焊接接头HAZ组织性能研究%Microstructure and Properties of Ferritic Stainless Steel CMT Welding HAZ

    Institute of Scientific and Technical Information of China (English)

    贺舒榕; 王文先; 张婷婷; 张昭晗

    2014-01-01

    针对铁素体不锈钢焊接HAZ晶粒易长大的问题,提出采用小热输入的CM T 焊接工艺。通过分析接头HAZ的显微组织、显微硬度和冲击性能,探讨了4003铁素体不锈钢焊接接头 HAZ组织和性能,并与常规MIG焊焊接接头试样的组织、性能进行对比。试验结果表明:采用CMT焊接工艺获得的接头 HAZ粗晶区宽度为460μm ,明显窄于M IG焊接接头的粗晶区宽度545μm ;CM T接头强度与M IG焊接接头显微硬度值相近,但CMT接头HAZ冲击韧性较MIG焊接接头试样提高了16.28%。%In this paper ,CM T welding process as a kind of low heat input process was adopted ,aiming at the problem that the ferritic stainless steel HAZ grain is easy to grow up .Contrast to the traditional MIG welding joints ,the CMT welding joints'appearance ,microstructure ,microhardness and impact property in HAZ were analyzed of the 4003 ferritic stainless steel . The results show that the width of joint coarse grain zone of the CMT welding is 460μm ,which is narrower than the width value 545 μm of MIG welding joint .The microhardness of the CMT welding joint is near to the MIG welding joint ,but the toughness is increased by 16 .28% .

  13. Elastic Softening of Surface Acoustic Wave Caused by Vacancy Orbital in Silicon Wafer

    Science.gov (United States)

    Mitsumoto, Keisuke; Akatsu, Mitsuhiro; Baba, Shotaro; Takasu, Rie; Nemoto, Yuichi; Goto, Terutaka; Yamada-Kaneta, Hiroshi; Furumura, Yuji; Saito, Hiroyuki; Kashima, Kazuhiko; Saito, Yoshihiko

    2014-03-01

    We have performed surface acoustic wave (SAW) measurements to examine vacancies in a surface layer of a boron-doped silicon wafer currently used in semiconductor industry. A SAW with a frequency of fs = 517 MHz was optimally generated by an interdigital transducer with a comb gap of w=2.5 µm on a piezoelectric ZnO film deposited on the (001) silicon surface. The SAW propagating along the [100] axis with a velocity of vs=4.967 km/s is in agreement with the Rayleigh wave, which shows an ellipsoidal trajectory motion in the displacement components ux and uz within a penetration depth of λp = 3.5 µm. The elastic constant Cs of the SAW revealed the softening of ΔCs/Cs = 1.9 × 10-4 below 2 K down to 23 mK. Applied magnetic fields of up to 2 T completely suppress the softening. The quadrupole susceptibilities based on the coupling between the electric quadrupoles Ou, Ov, and Ozx of the vacancy orbital consisting of Γ8-Γ7 states and the symmetry strains ɛu, ɛv, and ɛzx associated with the SAW account for the softening and its field dependence on Cs. We deduced a low vacancy concentration N = 3.1 × 1012/cm3 in the surface layer within λp = 3.5 µm of the silicon wafer. This result promises an innovative technology for vacancy evaluation in the fabrication of high-density semiconductor devices in industry.

  14. Thermodynamic behaviour of gliadins mixture and the glass-softening transition of its dried state.

    Science.gov (United States)

    Ferrari, C; Johari, G P

    1997-10-01

    The glass-softening transition of a mixture of gliadins extracted from wheat flour has been studied in its dry state by differential scanning calorimetry (DSC). Further, the rate of removal of its water vapours on its evaporation from a gliadins mixture containing different amounts of water has been investigated, and through this the presence of any exothermic effect that could be attributed to polymerization of gliadins has been examined. The heat absorbed in this evaporation is comparable with the heat of evaporation of pure water measured in a separate experiment in identical conditions. This showed that the gliadins mixture did not polymerize on heating up to 473 K in the presence of moisture. In this respect the behaviour of the gliadins mixture differs remarkably from that of gluten studied before (J Phys Chem 1996:100:19692). The effects of purge gas, helium and argon, on the calorimetric effects during the evaporation of water have been studied. A restudy of gluten shows that helium decreases substantially the endothermic signal in the DSC measurements, and thereby reveals the exothermic effects of polymerization in gluten, but argon does not do so. The structural relaxation time, t, of dry gliadins mixtures at different temperatures has been calculated from an analysis of its glass-softening endotherm. The temperature at which t = 1 ks is 452 K, and the Tg, obtained by the usual method of intersection of the straight lines drawn, is 443 K, 7 K higher than for the polymerized dry gluten, the distribution of relaxation time parameter is 0.25, and increase in the heat capacity in this range is 0.21 J/g K. Physical ageing effects are considerable in the gliadins mixture, which alters the glass-softening endotherm but not the structural relaxation time or its distribution.

  15. Partonic energy loss in ultrarelativistic heavy ion collisions jet suppression versus jet fragmentation softening

    CERN Document Server

    Lokhtin, Igor P

    2003-01-01

    We discuss the modification of a jet fragmentation function due to medium-induced partonic energy loss in context of leading particle observables in ultrarelativistic nucleus-nucleus interactions. We also analyze the relation between in-medium softening jet fragmentation function and suppression of the jet rates due to energy loss outside the jet cone. The predicted anti-correlation between two effects allows to probe a fraction of partonic energy loss carried out of the jet cone and truly lost to the jet.

  16. Insights into the softening of chaotic statistical models by quantum considerations

    Science.gov (United States)

    Cafaro, C.; Giffin, A.; Lupo, C.; Mancini, S.

    2012-05-01

    We analyze the information geometry and the entropic dynamics of a 3D Gaussian statistical model and compare our analysis to that of a 2D Gaussian statistical model obtained from the higher-dimensional model via introduction of an additional information constraint that resembles the quantum mechanical canonical minimum uncertainty relation. We uncover that the chaoticity of the 2D Gaussian statistical model, quantified by means of the Information Geometric Entropy (IGE), is softened with respect to the chaoticity of the 3D Gaussian statistical model.

  17. Role of electron concentration in softening and hardening of ternary molybdenum alloys

    Science.gov (United States)

    Stephens, J. R.; Witzke, W. R.

    1975-01-01

    Effects of various combinations of hafnium, tantalum, rhenium, osmium, iridium, and platinum in ternary molybdenum alloys on alloy softening and hardening were determined. Hardness tests were conducted at four test temperatures over the temperature range 77 to 411 K. Results showed that hardness data for ternary molybdenum alloys could be correlated with anticipated results from binary data based upon expressions involving the number of s and d electrons contributed by the solute elements. The correlation indicated that electron concentration plays a dominant role in controlling the hardness of ternary molybdenum alloys.

  18. Gurzadyan's Problem 5 and improvement of softenings for cosmological simulations using the PP method

    CERN Document Server

    Eingorn, Maxim

    2014-01-01

    This Letter is devoted to different modifications of two standard softenings of the gravitational attraction, which are commonly used in cosmological simulations based on the particle-particle (PP) method, and their comparison. It is demonstrated that some of the proposed alternatives lead to almost the same accuracy as in the case of the pure Newtonian interaction, even despite the fact that the force resolution is allowed to equal half the minimum interparticle distance. The revealed way of precision improvement gives an opportunity to succeed in solving Gurzadyan's Problem 5 and bring modern computer codes up to a higher standard.

  19. Effects Of Various Parameters On The Thickening Of Softening Plant Sludges

    DEFF Research Database (Denmark)

    Peters, Günther H.J.; Baumann, E. R.; Larson, M. A.

    1989-01-01

    photomicrographs indicated that only the calcium carbonate precipitate has a well-defined crystal structure. The shift of the crystal size distribution (CSD) to greater sizes, observed by comparing the different sludges, may be due to bigger calcite crystals rather than to crystal size changes caused......Spectroscopic and thermal data for sludges from full-scale softening plants showed calcium and magnesium precipitated as calcite and an amorphous hydrated hydroxide, respectively. Magnesium ions were not incorporated into the calcium lattice to form a magnesian calcite. Scanning electron...

  20. Ab initio investigation of the anomalous phonon softening in FeSi

    Science.gov (United States)

    Stern, Robin; Madsen, Georg K. H.

    2016-10-01

    The anomalous softening of the acoustic phonon peak in FeSi has recently received considerable experimental attention. In our work, we investigate the effect of thermal disorder on the lattice dynamics and the filling of the narrow band gap of FeSi using density functional theory. We show, by comparing the phonon density of states from temperature-independent and temperature-dependent force constants, that thermal structural disorder together with thermal expansion explains the anomalously strong renormalization of the acoustic phonons. Furthermore, we find an intricate interplay between thermal disorder and volume in gap closure.

  1. Influence of the dye transfer inhibitors for the washing of softened cotton fabric

    OpenAIRE

    Carrión Fité, Francisco Javier

    2014-01-01

    In this, work the performance of several dye transfer inhibitors (DTI) copolymers (PVP, PVNO and PVNO with PVP) was tested for use as DTIs in washing softened undyed cotton fabric, in the presence of a direct dye in the washing bath, with and without water hardness. Three direct dyes were tested: red, blue and yellow. The detergent used was composed of an LAS anionic surfactant and a non-ionic fatty alcohol ethoxylate surfactant with 7¿m. OE, both separately and in the different molar proport...

  2. The Effect of Hydrogen on the Solid Solution Strengthening and Softening of Nickel.

    Science.gov (United States)

    1981-11-01

    Afl-A108 654e ILLINOIS UNIV AT URBANA DEPT OF METALLURGY AND MININS--ETC F/6 11/6 THE EFFECT OF HYDROGEN ON THE SOLID SOLUTION STRFNSTNFNING ANfl...RESOLUTION TEST CHART NATIONAL HUR[AU OF STANDARDS 1963 A, " , ..... . .... .. i ....... .. .. . t , LEVEL THE EFFECT OF HYDROGEN ON THE SOLID SOLUTION STRENGTHENING...Availability Codes IIAvail and/or Dist Special THE EFFECT OF HYDROGEN ON THE SOLID SOLUTION STRENGTHENING AND SOFTENING OF NICKEL J. Eastman, F. Heuhaum, T

  3. Behaviorism

    Science.gov (United States)

    Moore, J.

    2011-01-01

    Early forms of psychology assumed that mental life was the appropriate subject matter for psychology, and introspection was an appropriate method to engage that subject matter. In 1913, John B. Watson proposed an alternative: classical S-R behaviorism. According to Watson, behavior was a subject matter in its own right, to be studied by the…

  4. Behaviorism

    Science.gov (United States)

    Moore, J.

    2011-01-01

    Early forms of psychology assumed that mental life was the appropriate subject matter for psychology, and introspection was an appropriate method to engage that subject matter. In 1913, John B. Watson proposed an alternative: classical S-R behaviorism. According to Watson, behavior was a subject matter in its own right, to be studied by the…

  5. Hot deformation behavior of FGH96 superalloys

    Institute of Scientific and Technical Information of China (English)

    Jiantao Liu; Guoquan Liu; Benfu Hu; Yuepeng Song; Ziran Qin; Yiwen Zhang

    2006-01-01

    The hot deformation behavior of FGH96 superalloys at 1070-1170℃ and 5×10-4-2×10-1 s-1 were investigated by means of the isothermal compression tests at a Gleeble-1500 thermal mechanical simulator. The results show that dynamic recovery acts as the main softening mechanism below 2×10-3 s-1, whereas dynamic recrystallization acts as the main softening mechanism above 2×10-3 s-1during deformation; the temperature increase caused by the deformation and the corresponding softening stress is negligible; the thermal-mechanical constitutive model to describe the hot deformation behavior is given, and the value of the apparent deformation activation energy (Qdef) is determined to be 354.93 kJ/mol.

  6. Use of sonication for in-well softening of semivolatile organic compounds. 1997 annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    Peters, R.W.; Manning, J. [Argonne National Lab., IL (US); Hoffman, M.R. [California Inst. of Tech., Pasadena, CA (US); Gorelick, S. [Stanford Univ., CA (US)

    1997-01-01

    'This project investigates the in-situ degradation of semivolatile organic compounds (SVOCs) and volatile organic compounds (VOCs) using in-well sonication, in-well vapor stripping, and bioremediation. Pretreating groundwaters with sonication techniques in-situ would form VOCs that can be effectively removed by in-well vapor stripping and bioremediation. The mechanistic studies focus on the coupling of megasonics and ultrasonics to soften (i.e., partially degrade) the SVOCs; oxidative reaction mechanism studies; surface corrosion studies (on the reactor walls/well); enhancement due to addition of oxidants, quantification of the hydroxyl radical formation; identification/quantification of degradation products; volatility/degradability of the treated waters; development of a computer simulation model to describe combined in-well sonication/in-well vapor stripping/bioremediation; systems analysis/economic analysis; large laboratory-scale experiment verification; and field demonstration of the integrated technology. Benefits of this approach include: (1) Remediation is performed in-situ; (2) The treatment systems complement each other; their combination can drastically reduce or remove SVOCs and VOCs; (3) Ability to convert hard-to-degrade organics into more volatile organic compounds; (4) Ability to remove residual VOCs and softened SVOCs through the combined action of in-well vapor stripping and biodegradation; (5) Does not require handling or disposing of water at the ground surface; and (6) Cost-effective and improved efficiency, resulting in shortened clean-up times to remediate a site.'

  7. Phonon softening induced cubic-to-tetragonal phase transition in ReO3

    Science.gov (United States)

    Liu, Yaming; Zhang, Niu; Jia, Yu; Sun, Qiang; Chao, Mingju

    2015-10-01

    Within density functional theory, the structural, electronic and lattice dynamical properties of ReO3 in cubic Pm-3m and tetragonal P4/mbm phases are studied by using quasiharmonic approximation. The enthalpy-pressure curves show that a phase transition may take place at 5.0 kbar and the nonexistence of imaginary frequency in phonon dispersions demonstrates the two phases are dynamically stable under proper conditions. With the increase of pressure, an obvious softening of M3 mode at M point appears in cubic phase, and a cubic-to-tetragonal phase transition is accompanied with the presence of negative frequency in M3 mode at 5.0 kbar. In detail, one type of O atoms displaced from x = 0.2500 to x = 0.2401, which corresponds to the softening of M3 mode, are responsible for the phase transition. Our theoretical results show that ReO3 can exist in the tetragonal P4/mbm phase, and a cubic-to-tetragonal phase transition will appear at around 5.0 kbar.

  8. Influence of ethanol concentration on softening tests for cross-link density evaluation of dental composites

    Directory of Open Access Journals (Sweden)

    Rafael Ratto de Moraes

    2007-03-01

    Full Text Available This study investigated the influence of ethanol concentration on softening tests for cross-link density evaluation (microhardness of dental composites. Specimens of Filtek Z100 (3M ESPE were light-activated by standard or pulse-delay methods. After initial Knoop hardness readings (KHN1, half of specimens (n = 10 for each irradiation method was stored in 100% ethanol, and half in 75% ethanol, during 24 hours, and hardness was determined anew. Hardness deterioration (DKHN was recorded as the difference between pre and post-storage values. KHN1 data were submitted to one-way ANOVA and Tukey's test (alpha = 0.05, and hardness deterioration was analyzed by two-way ANOVA and Tukey's test (alpha= 0.05. For KHN1, no significant differences were detected between the activation modes (p = 0.697. Samples light-activated by the pulse-delay method presented significantly higher softening compared to the standard mode when samples were immersed in 100% ethanol. Conversely, no significant differences between curing modes were detected for samples stored in 75% ethanol.

  9. Synthetic Musk Fragrances in a Conventional Drinking Water Treatment Plant with Lime Softening.

    Science.gov (United States)

    Wombacher, William D; Hornbuckle, Keri C

    2009-11-01

    Synthetic musk fragrances are common personal care product additives and wastewater contaminants that are routinely detected in the environment. This study examines the presence eight synthetic musk fragrances (AHTN, HHCB, ATII, ADBI, AHMI, musk xylene, and musk ketone) in source water and the removal of these compounds as they flow through a Midwestern conventional drinking water plant with lime softening. The compounds were measured in water, waste sludge, and air throughout the plant. HHCB and AHTN were detected in 100% of the samples and at the highest concentrations. A mass balance on HHCB and AHTN was performed under warm and cold weather conditions. The total removal efficiency for HHCB and AHTN, which averaged between 67% to 89%, is dominated by adsorption to water softener sludge and its consequent removal by sludge wasting and media filtration. Volatilization, chlorine disinfection, and the disposal of backwash water play a minor role in the removal of both compounds. As a result of inefficient overall removal, HHCB and AHTN are a constant presence at low levels in finished drinking water.

  10. Damage constitutive model for strain-softening rock based on normal distribution and its parameter determination

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Firstly, using the damage model for rock based on Lemaitre hypothesis about strain equivalence, a new technique for measuring strength of rock micro-cells by adopting the Mohr-Coulomb criterion was developed, and a statistical damage evolution equation was established based on the property that strength of micro-cells is consistent with normal distribution function, through discussing the characteristics of random distributions for strength of micro-cells, then a statistical damage constitutive model that can simulate the full process of rock strain softening under specific confining pressure was set up. Secondly, a new method to determine the model parameters which can be applied to the situations under different confining pressures was proposed, by deeply studying the relations between the model parameters and characteristic parameters of the full stress-strain curve under different confining pressures. Therefore, a unified statistical damage constitutive model for rock softening which can reflect the effect of different confining pressures was set up. This model makes the physical property of model parameters explicit, contains only conventional mechanical parameters, and leads its application more convenient. Finally, the rationality of this model and its parameters-determining method were identified via comparative analyses between theoretical and experimental curves.

  11. Reversible stress softening of collagen based networks from the jumbo squid mantle (Dosidicus gigas)

    Energy Technology Data Exchange (ETDEWEB)

    Torres, F.G., E-mail: fgtorres@pucp.edu.pe [Department of Mechanical Engineering, Catholic University of Peru, Lima 32 (Peru); Troncoso, O.P.; Rivas, E.R. [Department of Mechanical Engineering, Catholic University of Peru, Lima 32 (Peru); Gomez, C.G. [Departament de Química Física and Institut de Ciencia dels Materials, Universitat de València, Dr. Moliner 50, Burjassot, E-46100 Valencia (Spain); Lopez, D. [Instituto de Ciencia y Tecnología de Polímeros, C.S.I.C., Calle Juan de la Cierva 3, 28006 Madrid (Spain)

    2014-04-01

    Dosidicus gigas is the largest and one of the most abundant jumbo squids in the eastern Pacific Ocean. In this paper we have studied the muscle of the mantle of D. gigas (DGM). Morphological, thermal and rheological properties were assessed by means of atomic force microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, differential scanning calorimetry, thermogravimetry and oscillatory rheometry. This study allowed us to assess the morphological and rheological properties of a collagen based network occurring in nature. The results showed that the DGM network displays a nonlinear effect called reversible stress softening (RSS) that has been previously described for other types of biological structures such as naturally occurring cellulose networks and actin networks. We propose that the RSS could play a key role on the way jumbo squids withstand hydrostatic pressure. The results presented here confirm that this phenomenon occurs in a wider number of materials than previously thought, all of them exhibiting different size scales as well as physical conformation. - Highlights: • We studied the structure property relationships of the jumbo squid mantle. • Rheological tests showed that such a mantle exhibits reversible stress softening (RSS). • RSS could also play a role on the way jumbo squids withstand hydrostatic pressure.

  12. INVESTIGATION OF SOFTENING AGENT PREPARATION AND PERFORMANCE OF HANDMADE ECOCOMPOSITES WITH CONIFEROUS WOOD AND BASALT FIBERS

    Institute of Scientific and Technical Information of China (English)

    Guangjian Wang; Deku Shang; Kailiang Zhang; Linna Hu; Zhenhua Guo

    2004-01-01

    In this investigation, basalt mineral fiber softening agent was prepared in order to obtain desirable flexible performance. Stability and physical chemistry natures of softening agent were evaluated by particle size distribution, dilution, storage and folding endurance etc. Constitutes of basalt and wood fibers were determined by energy dispersion analysis X-ray which served as an accessory of scanning electron microscopy (SEM-EDAX). Naturally degradable ecocomposite was prepared by basalt and wood fibers. The results of SEM observation illustrated that the wood and basalt fibers were blended uniformly. The impact factors of beating degree, content of wood fibers and adhesive etc. were discussed. The structure of the naturally degradable ecocomposite was contrasted with that of pure wood fibers and the cause of excellent filtration performance was analyzed. Compared with traditional methods, it was of saving wood resource,a large amount of water and reducing second pollution. As a consequence, the ecocomposite harmonized with environment and accorded with requirement of benignly friendly environment.

  13. TO SELECTION OF TECHNOLOGICAL SCHEME OF SOFTENING HEAT TREATMENT FOR HIGH CHROMIUM CAST IRON

    Directory of Open Access Journals (Sweden)

    V. G. Efremenko

    2014-03-01

    Full Text Available Purpose. High chromium cast irons with austenitic matrix have low machinability. The aim of work is search of new energy-saving modes of preliminary softening heat treatment enhancing the machinability of castings by forming an optimum microstructure. Methodology. Metallographic analysis, hardness testing and machinability testing are applied. Findings. It was found out that high temperature annealing with continuous cooling yields to martensite-austenite matrix in cast iron 270Х15Г2Н1MPhT, which abruptly affects the machinability of cast iron. Significant improvement of machinability is achieved by forming of structure "ferrite + granular carbides" and by decline of hardness to 37-39 HRC in the case of two-stage isothermal annealing in the subcritical temperature range or by the use of quenching and tempering (two-step or cyclic. Originality. It was found that the formation of the optimal structure of the matrix and achievement of desired hardness level needed for improving machinability of high chromium cast iron containing 3 % austenite-forming elements, can be obtained: 1 due to pearlite original austenite followed by spherodization eutectoid carbides, and 2 by getting predominantly martensite structure followed by the decay of martensite and carbides coagulation at high-temperature tempering. Practical value. The new energy-saving schemes of softening heat treatment to ensure the growth of machinability of high chromium cast iron, alloyed by higher quantity of austenite forming elements, are proposed.

  14. A local prescription for the softening length in self-gravitating gaseous discs

    CERN Document Server

    Huré, Jean-Marc

    2009-01-01

    In 2D-simulations of self-gravitating gaseous discs, the potential is often computed in the framework of "softened gravity" initially designed for N-body codes. In this special context, the role of the softening length LAMBDA is twofold: i) to avoid numerical singularities in the integral representation of the potential (i.e., arising when the relative separation vanishes), and ii) to acount for stratification of matter in the direction perpendicular to the disc mid-plane. So far, most studies have considered LAMBDA as a free parameter and various values or formulae have been proposed without much mathematical justification. In this paper, we demonstrate by means of a rigorous calculus that it is possible to define LAMBDA such that the gravitational potential of a flat disc coincides at order zero with that of a geometically thin disc of the same surface density. Our prescription for LAMBDA, valid in the local, axisymmetric limit, has the required properties i) and ii). It is mainly an analytical function of ...

  15. Softening of the elastic shear mode C{sub 66} in iron-based superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Boehmer, Anna; Burger, Philipp [Karlsruher Institut fuer Technologie, Institut fuer Festkoerperphysik, D-76021 Karlsruhe (Germany); Karlsruher Institut fuer Technologie, Fakultaet fuer Physik, D-76128 Karlsruhe (Germany); Hardy, Frederic; Schweiss, Peter; Fromknecht, Rainer; Wolf, Thomas; Meingast, Christoph [Karlsruher Institut fuer Technologie, Institut fuer Festkoerperphysik, D-76021 Karlsruhe (Germany); Reinecker, Marius; Schranz, Wilfried [Universitaet Wien, Fakultaet fuer Physik, A-1090 Wien, Vienna (Austria)

    2013-07-01

    The structural phase transition of underdoped iron-based superconductors is accompanied by a large softening of the elastic shear mode C{sub 66}, which has attracted considerable attention. This softening has been discussed both in terms of orbital and spin-nematic fluctuations which would be responsible for the structural phase transition and, possibly, superconductivity. However, sample requirements have so far restricted experimental investigations of C{sub 66} (via measurements of the ultrasound velocity) to the Ba(Fe,Co){sub 2}As{sub 2} system. Here, we report on a new technique, based on a three-point bending setup, to probe the Young's modulus of a sample with a capacitance dilatometer. For certain orientations, the Young's modulus is related to the elastic constant C{sub 66} whose effective temperature dependence can be obtained. Platelet-like samples, as frequently encountered for iron-based systems, are easily studied with our setup. Data on several systems are presented and discussed.

  16. A Technique for Mapping Characteristic Lengths to Preserve Energy Dissipated via Strain Softening in a Multiscale Analysis

    Science.gov (United States)

    Pineda, Evan J.; Bednarcyk, Brett A.; Arnold, Steven M.

    2014-01-01

    It is often advantageous to account for the microstructure of the material directly using multiscale modeling. For computational tractability, an idealized repeating unit cell (RUC) is used to capture all of the pertinent features of the microstructure. Typically, the RUC is dimensionless and depends only on the relative volume fractions of the different phases in the material. This works well for non-linear and inelastic behavior exhibiting a positive-definite constitutive response. Although, once the material exhibits strain softening, or localization, a mesh objective failure theories, such as smeared fracture theories, nodal and element enrichment theories (XFEM), cohesive elements or virtual crack closure technique (VCCT), can be utilized at the microscale, but the dimensions of the RUC must then be defined. One major challenge in multiscale progressive damage modeling is relating the characteristic lengths across the scales in order to preserve the energy that is dissipated via localization at the microscale. If there is no effort to relate the size of the macroscale element to the microscale RUC, then the energy that is dissipated will remain mesh dependent at the macroscale, even if it is regularized at the microscale. Here, a technique for mapping characteristic lengths across the scales is proposed. The RUC will be modeled using the generalized method of cells (GMC) micromechanics theory, and local failure in the matrix constituent subcells will be modeled using the crack band theory. The subcell characteristic lengths used in the crack band calculations will be mapped to the macroscale finite element in order to regularize the local energy in a manner consistent with the global length scale. Examples will be provided with and without the regularization, and they will be compared to a baseline case where the size and shape of the element and RUC are coincident (ensuring energy is preserved across the scales).

  17. A COMBINED PARAMETRIC QUADRATIC PROGRAMMING AND PRECISE INTEGRATION METHOD BASED DYNAMIC ANALYSIS OF ELASTIC-PLASTIC HARDENING/SOFTENING PROBLEMS

    Institute of Scientific and Technical Information of China (English)

    张洪武; 张新伟

    2002-01-01

    The objective of the paper is to develop a new algorithm for numericalsolution of dynamic elastic-plastic strain hardening/softening problems. The gradientdependent model is adopted in the numerical model to overcome the result mesh-sensitivity problem in the dynamic strain softening or strain localization analysis.The equations for the dynamic elastic-plastic problems are derived in terms of theparametric variational principle, which is valid for associated, non-associated andstrain softening plastic constitutive models in the finite element analysis. The preciseintegration method, which has been widely used for discretization in time domain ofthe linear problems, is introduced for the solution of dynamic nonlinear equations.The new algorithm proposed is based on the combination of the parametric quadraticprogramming method and the precise integration method and has all the advantagesin both of the algorithms. Results of numerical examples demonstrate not only thevalidity, but also the advantages of the algorithm proposed for the numerical solutionof nonlinear dynamic problems.

  18. Phonon softening in the CDW Systems NbSe{sub 2} and TiSe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Hott, Roland; Heid, Rolf; Bohnen, Klaus-Peter [Karlsruhe Institute of Technology, Institute of Solid State Physics, Karlsruhe (Germany); Weber, Frank [Karlsruhe Institute of Technology, Institute of Solid State Physics, Karlsruhe (Germany); Materials Science Division, Argonne National Laboratory, Argonne, Illinois (United States); Rosenkranz, Stephan; Castellan, John-Paul; Osborn, Raymond [Materials Science Division, Argonne National Laboratory, Argonne, Illinois (United States); Egami, Takeshi [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee (United States); Said, Ayman [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois (United States); Reznik, Dmitry [Karlsruhe Institute of Technology, Institute of Solid State Physics, Karlsruhe (Germany); Department of Physics, University of Colorado at Boulder, Boulder, Colorado (United States)

    2011-07-01

    We investigated the soft-mode behaviour of phonons in the charge density wave (CDW) systems NbSe{sub 2} and TiSe{sub 2} both theoretically in Density Functional Theory (DFT) based on ab-initio phonon calculations and experimentally by means of high resolution Inelastic X-ray Scattering (IXS). For both materials, the theoretical predictions for the phonon softening using the experimental lattice parameters coincide with the experimentally observed CDW instability behaviour. While TiSe{sub 2} shows a rather sharp phonon anomaly at T=190 K, the anomaly in NbSe{sub 2} at T=33 K is much broader than expected for a Fermi surface nesting driven CDW instability. For NbSe{sub 2}, we exclude Fermi surface nesting as main origin of the phonon softening. For TiSe{sub 2}, there is no need to go beyond DFT in order to describe the phonon softening.

  19. Fracture propagation in Indiana Limestone interpreted via linear softening cohesive fracture model

    Science.gov (United States)

    Rinehart, Alex J.; Bishop, Joseph E.; Dewers, Thomas

    2015-04-01

    We examine the use of a linear softening cohesive fracture model (LCFM) to predict single-trace fracture growth in short-rod (SR) and notched 3-point-bend (N3PB) test configurations in Indiana Limestone. The broad goal of this work is to (a) understand the underlying assumptions of LCFM and (b) use experimental similarities and deviations from the LCFM to understand the role of loading paths of tensile fracture propagation. Cohesive fracture models are being applied in prediction of structural and subsurface fracture propagation in geomaterials. They lump the inelastic processes occurring during fracture propagation into a thin zone between elastic subdomains. LCFM assumes that the cohesive zone initially deforms elastically to a maximum tensile stress (σmax) and then softens linearly from the crack opening width at σmax to zero stress at a critical crack opening width w1. Using commercial finite element software, we developed LCFMs for the SR and N3PB configurations. After fixing σmax with results from cylinder splitting tests and finding an initial Young's modulus (E) with unconfined compressive strength tests, we manually calibrate E and w1 in the SR model against an envelope of experimental data. We apply the calibrated LCFM parameters in the N3PB geometry and compare the model against an envelope of N3PB experiments. For accurate simulation of fracture propagation, simulated off-crack stresses are high enough to require inclusion of damage. Different elastic moduli are needed in tension and compression. We hypothesize that the timing and location of shear versus extensional micromechanical failures control the qualitative macroscopic force-versus-displacement response in different tests. For accurate prediction, the LCFM requires a constant style of failure, which the SR configuration maintains until very late in deformation. The N3PB configuration does not maintain this constancy. To be broadly applicable between geometries and failure styles, the LCFM

  20. Use prospect of the of athermic technologies of metal softening for rolling stock elements

    Directory of Open Access Journals (Sweden)

    N.N. Grischenko

    2013-06-01

    Full Text Available Purpose. The purpose of work is the possibility estimation of аthermic technologies use of cold-deformed metal softening for elements of railway car body and wheel. Methodology. The material for research is the carbon steel of the wheel rim fragment containing 0.55%С, 0.74%Mn, 0.33%Si, and the steel 20. The wheel steel is studied after heat strengthening and cold work after operation. Steel 20 is studied after plastic cold work by rolling. Electric pulse treatment (ET is carried out on the special equipment. As the property of metal strength the Vickers hardness number is used. The microstructure research is carried out using the light and electronic microscope. Findings. During operation of the rolling stock elements with different strength level origin of damages on metallic surfaces is caused by a simultaneous load action. Taking into account that forming of breakdown sites is largely determined by the state of metal volumes nearby the places of maximal active voltages, the technology development of defect accumulation slowdown or the level of active voltages development allow one to prolong the operating term of rolling stock elements. After electric pulse treatment of the wheel rim fragment the regular changes of metal internal structure corresponded to the hardness changes. The hardness of low carbon steel increases proportional to the increase of the level of cold work by rolling. Alternating bending of the cold-deformed flat is accompanied by strength decrease, which is caused by the metal substructure changes. Originality. The softening process of the cold-worked steel is accompanied by substructure changes, which to a greater extent correspond to the hardening development from the plastic cold-work: dispersion of the dislocation cellular structure, formation of the new sub boundaries and displacement of the formed sub boundaries. Practical value. Introduction of electric pulse treatment in the conditions of railway depots repair base

  1. X80管线钢焊接热影响区组织性能改善措施%Discussion on Improving Processing Measure of Welding HAZ Microstructure Performance for X80 Pipeline Steel

    Institute of Scientific and Technical Information of China (English)

    赵波; 李国鹏; 王旭; 谷雨; 肖福仁

    2014-01-01

    采用热模拟试验方法,研究了一种X80管线钢热影响区在不同冷速、焊接线能量和峰值温度下的金相组织和力学性能变化规律。试验表明:适当提高焊缝热影响区冷速可以改善其组织和强韧性能;在相同焊接线能量的条件下,试验X80钢焊接热影响区的临界区、粗晶区冲击韧性最差并分别出现一处谷值,细晶区强度最差;采用较小线能量焊接有利于改善热影响区综合强韧性;采用高熔敷率复合高效多丝埋弧焊低线能量化焊接工艺、随焊加速冷却工艺、焊后焊缝及热影响区局部中频正火热处理工艺,可以有效改善X80管线钢热影响区强韧匹配性能。%By using the thermal simulation test, the changing rules of the metallurgical structure and mechanical properties of weld HAZ of X80 pipeline steel under different cooling rates, welding heat inputs and peak temperatures were discussed in this essay. The tests showed that: Appropriate increase of the cooling rate in the weld HAZ can improve the microstructure, strength and toughness of the weld HAZ;under the same welding heat input, the impact toughness of the critical zone and the coarse grain zone are poor and a valley occurs respectively in these two zones, the strength of the fine grain zone is the lowest;welding adopting a relatively low heat input is beneficial to improve the comprehensive strength and toughness of weld HAZ. According to analysis result, a welding procedure with high deposit rate, high-efficiency multi-wire submerged arc welding and lower heat input, a simultaneous accelerate cooling process, and a local intermediate-frequency normalizing treatment of weld & HAZ post-welding can effectively improve the comprehensive strength-toughness performance of weld HAZ of pipeline steel.

  2. Endüstriyel İşletmelerde Franchising Model Önerisi: Hazır Beton Sektöründe Bir Uygulama

    Directory of Open Access Journals (Sweden)

    İpek Kazançoğlu

    2016-12-01

    Full Text Available Endüstriyel pazarda faaliyet gösteren firmaların daha hızlı büyüyerek, yeni pazarlara açılmasında franchising sistemi bir yeni bir satış, dağıtım kanalı olarak değerlendirilmektedir. Bu araştırmada amaç,  hazır beton sektöründe faaliyet gösteren bir firmanın franchising sistemini bir iş modeli olarak benimseme kararında dikkat etmesi gereken unsurları ve karşılaşılan zorlukları incelemektedir. Örnek olay çalışması olarak ele alınan çalışmada,  BATIBETON A.Ş. firmasının yedi yöneticiyle BATIBETON markasının franchising uygulamalarına ilişkin görüşlerini öğrenmek amacıyla derinlemesine görüşmeler yapılmıştır. Bu görüşmeler sonucunda, franchising sisteminin hazır beton sektöründe bir model önerisi olarak uygulanıp/uygulanmayacağı değerlendirilmiştir. Yapılan görüşmelerden elde edilen bulguların diğer endüstriyel işletmeler içinde geliştirilebilecek bir franchising iş modeli kararında etkili olabilecek faktörlerin anlaşılması yönünden uygulamaya katkı sağlayacağı düşünülmektedir.

  3. Zihinsel özürlü bireylere yiyecek hazırlama becerilerinin öğretimi ile ilgili alan yazın taraması

    Directory of Open Access Journals (Sweden)

    Funda Bozkurt

    2003-07-01

    Full Text Available Çalışmanın amacı, zihin özürlü bireylere yiyecek hazırlama becerilerinin öğretimi konusunda yürütülen çalışmaları, araştırmaya katılan denekler, ortam, hedef davranışlar, kullanılan öğretim yöntemi, araştırma modeli ve sonuçları açısından incelemektir. Bu amaçla, çalışmada bu konuda yürütülen araştırmalar, sıralanan özellikleri açısından tartışılmıştır. Çalışmada, 1988-2002 yılları arasında, zihin özürlü bireylere yiyecek hazırlama (pişirme becerilerinin öğretimine ilişkin yürütülen uygulamalı araştırmalar incelenmiştir. Çalışma sonunda zihin özürlü öğrencilerle çalışan öğretmen, araştırmacı ve uygulamacılara özetlenen çalışmalar doğrultusunda önerilerde bulunulmuştur. The purpose of the study is to examine the research studies on teaching food preparation skills to individuals with retardation in terms of participants, settings, targets bahaviors, instructional procedures, research design and findings. Furthermore, a discussion was conducted in terms of the above variables used in those studies. A review of literature was completed to find out the related published research articles from 1988 to 2002. At the enf of the study, recommendations are provided to teachers, researchers and practioners for teaching food preparation skills to students with mental retardation.

  4. Fatigue performance and cyclic softening of F82H, a ferritic martensic steel

    Energy Technology Data Exchange (ETDEWEB)

    Stubbins, J.F. [Univ. of Illinois, Urbana, IL (United States); Gelles, D.S. [Pacific Northwest National Laboratory, Richland, WA (United States)

    1996-04-01

    The room temperature fatigue performance of F82H has been examined. The fatigue life was determined in a series of strain-controlled tests where the stress level was monitored as a function of the number of accrued cycles. Fatigue lives in the range of 10{sup 3} to 10{sup 6} cycles to failure were examined. The fatigue performance was found to be controlled primarily by the elastic strain range over most of the range of fatigue lives examined. Only at low fatigue lives did the plastic strain range contribute to the response. However, when the significant plastic strain did contribute, the material showed a tendency to cyclically soften. That is the load carrying capability of the material degrades with accumulated fatigue cycles. The overall fatigue performance of the F82H alloy was found to be similiar to other advanced martensitic steels, but lower than more common low alloy steels which possess lower yield strengths.

  5. Pseudo-periodic surrogate test to sample time series in stochastic softening Duffing oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Gan Chunbiao [Department of Mechanics, CMEE, Zhejiang University, Hangzhou 310027 (China)]. E-mail: cb_gan@zju.edu.cn

    2006-09-11

    Identification of typical noise-contaminated sample response is a hard task in a nonlinear system under stochastic background since irregularity of the sample response may come from measure noise, dynamical noise, or nonlinear effect, etc., and conventional dynamical methods are generally not useful. Here, the pseudo-periodic surrogate algorithm by Small is employed to test the sample time series in the softening Duffing oscillator under the Gaussian white noise excitation. The correlation dimensions of the noisy periodic and the noise-induced chaotic time series of the system are compared with those of their corresponding surrogate data respectively, the leading Lyapunov exponents by Rosenstein's algorithm are also presented for comparison.

  6. A work softening joint element used in dynamic analysis of soil-structure

    Science.gov (United States)

    Toki, Kenzo; Yongen, Cai; Zhendong, Zhao

    1989-11-01

    This paper introduces an elasto-plastic joint element characterised by strain hardening and softening in the analysis of dynamic soil-structure interaction. The phenomena of separation and sliding on the contact surface between soil and structure can be better simulated and the process can also be described. The interaction problems in a typical soil-structure system are analyzed in terms of elasto-plastic joint element as well as elastic ones. The results show that the elasto-plastic joint element is much better than the elastic one in modelling, especially in that the relative displacements accross the joint element can be much greater than that of the elastic case. Separation and sliding are not only related to the coefficient of friction and cohesion but also to their changes with plastic volumetric strain.

  7. A work-hardening and softening constitutive model for sand: modified plastic strain energy approach

    Institute of Scientific and Technical Information of China (English)

    Fangle Peng; M.S.A. Siddiquee; Shaoming Liao

    2005-01-01

    The paper describes an energy-based constitutive model for sand, which is modified based on the modified plastic strain energy approach, represented by a unique relationship between the modified plastic strain energy and a stress parameter, independent of stress history. The modified plastic strain energy approach was developed based on results from a series of drained plastic strain compression tests along various stress paths on saturated dense Toyoura sand with accurate stress and strain measurements. The proposed model is coupled with an isotropically work-hardening and softening, non-associtated, elasto-plastic material description. The constitutive model concerns the inherent and stress systeminduced cross-anisotropic elastic deformation properties of sand. It is capable of simulating the deformation characteristics of stress history and stress path, the effects of pressure level, anisotropic strength and void ratio, and the strain localization.

  8. Unified solution of limit loads of thick wall cylinder subject to external pressure considering strain softening

    Institute of Scientific and Technical Information of China (English)

    CHEN Changfu; XIAO Shujun; YANG Yu

    2007-01-01

    Based on the unified strength theory [1],a unified strength criterion for strain softening materials,such as concrete or rock,was derived,and the elastic and plastic limit loads of a thick-walled cylinder made of these materials subject to external pressure were also given.In addition,the influence of some factors on the limit loads of such cylinders as the ratio of the external radius to intemal radius,rb/ra,the coefficient b,which reflects the effect of medium principal stress and the normal stress of the relevant surface on the material destroy degree,the ratio of tensile strength to compressed strength of the material,α,and the damage variable β were discussed in detail.Some examples were given and some meaningful results were obtained.

  9. Improved actuation strain of PDMS-based DEA materials chemically modified with softening agents

    Science.gov (United States)

    Biedermann, Miriam; Blümke, Martin; Wegener, Michael; Krüger, Hartmut

    2015-04-01

    Dielectric elastomer actuators (DEAs) are smart materials that gained much in interest particularly in recent years. One active field of research is the improvement of their properties by modification of their structural framework. The object of this work is to improve the actuation properties of polydimethylsiloxane (PDMS)-based DEAs by covalent incorporation of mono-vinyl-terminated low-molecular PDMS chains into the PDMS network. These low-molecular units act as a kind of softener within the PDMS network. The loose chain ends interfere with the network formation and lower the network's density. PDMS films with up to 50wt% of low-molecular PDMS additives were manufactured and the chemical, mechanical, electrical, and electromechanical properties of these novel materials were investigated.

  10. Analysis on cohesive crack opening displacement considering the strain softening effect

    Institute of Scientific and Technical Information of China (English)

    WANG; Limin; XU; Shilang; ZHAO; Xiqiang

    2006-01-01

    In order to investigate the crack propagation in quasi-brittle materials like rock, ceramic and concrete, Hillerborg and his co-researchers abstracted the fracture process zone in front of a stress free crack in terms of a "fictitious crack zone". On the fictitious crack zone, cohesive stresses distribute following a given softening relationship of stress vs. crack opening. Based on the polynomial or power series expression of cohesive crack opening displacement, the relationship of the cohesive stress vs. the crack opening displacement is established using elastic theory and integral equation, and some unknown physics variables are obtained using variation approach. The calculation results gained in this paper are close to the experimentally test ones.

  11. A local prescription for the softening length in self-gravitating gaseous discs

    Science.gov (United States)

    Huré, J.-M.; Pierens, A.

    2009-11-01

    In 2D-simulations of self-gravitating gaseous discs, the potential is often computed in the framework of “softened gravity” initially designed for N-body codes. In this special context, the role of the softening length λ is twofold: i) to avoid numerical singularities in the integral representation of the potential (i.e., arising when the separation |r -r'| → 0); and ii) to account for stratification of matter in the direction perpendicular to the disc mid-plane. So far, most studies have considered λ as a free parameter and various values or formulae have been proposed without much mathematical justification. In this paper, we demonstrate by means of a rigorous calculus that it is possible to define λ such that the gravitational potential of a flat disc coincides at order zero with that of a geometrically thin disc of the same surface density. Our prescription for λ, valid in the local, axisymmetric limit, has the required properties i) and ii). It is mainly an analytical function of the radius and disc thickness, and is sensitive to the vertical stratification. For mass density profiles considered (namely, profiles expandable over even powers of the altitude), we find that λ: i) is independant of the numerical mesh, ii) is always a fraction of the local thickness H; iii) goes through a minimum at the singularity (i.e., at null separation); and iv) is such that 0.13 ⪉ λ/H ⪉ 0.29 typically (depending on the separation and on density profile). These results should help us to improve the quality of 2D- and 3D-simulations of gaseous discs in several respects (physical realism, accuracy, and computing time).

  12. Influence Mechanism of Endogenous Abscisic Acid on Storage Softening Process of Hardy Kiwifruit

    Directory of Open Access Journals (Sweden)

    Li Shuqian

    2014-01-01

    Full Text Available In order to study the relation of Abscisic Acid (ABA with other biochemistry factors during hardy kiwifruit softening process. The changing trend of ABA under the fruits storage conditions of 20 and 0C was analyzed. A conclusion is drawn as below: During storage under 20C, it shows the highest content of ABA in 4 days to 222.19 &mu g/L, which reaches the almost same content in 3 and 5 days. The value keeps inclining since 5 days and decline rate is lower in 7 and 8 days. The lowest value is reached to 20.88 &mug/L in 10 days. During storage under 0C, ABA content is at a relatively high level but shows the slow down trend. ABA content falls greatly from 9 to 11 days. After this period, ABA content still follows up-trend and declining then. The peak appears in 15 days to 90.49 &mug/L, but it is lower than that in the first nine days. Moreover, peak during storage in environment under 0C is lower than that during the storage in environment at normal temperature, accordingly delaying fruit softening. As the ABA content rises to the highest level, the fruit hardness drops drastically. When ABA content slightly changes, the hardness decreases gently. ABA content is featured that same changing trend of ethylene content, respiratory intensity, pectase content and amylase content. Moreover, ABA has the same peak appearance time as amylase but it is later than appearance of both pectase and ethylene, they basically match each other. The rule of peak appearance time is not obvious for ABA and amylase. Mutual inhibition exists between peak appearance time of ABA and respiratory intensity. Quick ABA rise is accompanied with slow amylase rise and vice versa.

  13. 钛合金片层组织两相区变形时的流动软化机理分析%FLOW SOFTENING MECHANSIM OF A Ti ALLOY WITH LAMELLAR STRUCTURE DURING SUBTRANSUS DEFORMATION

    Institute of Scientific and Technical Information of China (English)

    宋鸿武; 张士宏; 程明; 李臻熙; 曹春晓; 包春玲

    2011-01-01

    钛合金片层组织在两相区变形时流动应力随应变的增加普遍表现为快速硬化和持续软化的特征.为了研究该流动软化的机理,采用等温热压缩实验研究了TC11合金片层组织在温度890-995℃和应变速率0.01-10 s-1范围内的热变形行为.理论计算表明α/β片层界面(α片层内孪晶界)产生的Hall-Petch强化效应远大于片层束集边界.TC11合金片层组织高温变形的流动软化机理可归结为硬滑移模式向软滑移模式转变导致Hall-Petch强化效应的减弱.%The flow stress has a considerable flow softening after a peak strain hardening at very low strains for Ti alloys with lamellar structure during subtransus deformation. In order to study the mechanism of such flow softening behavior, the deformation behavior of TC11 Ti alloy with a lamellar structure was studied using isothermal hot compression tests under a temperature range of 890-995 ℃ and a strain rate range of 0.01-10 s-1. Theoretical calculation shows the Hall-Petch strengthening effects induced by α/β interface as well as the twin boundary in α lamellar are far more significant than that of the colony boundary. The flow softening can be related to reduction of Hall-Petch strengthening effects due to transfer from the hard slip mode to the soft one.

  14. A round-robin test with thermal simulation of the welding HAZ to draw CCT diagrams: a need for harmonized procedures and microconstituent terminologies

    Directory of Open Access Journals (Sweden)

    Américo Scotti

    2014-09-01

    Full Text Available Thermal simulations of heat affected zone (HAZ have been widely used. This is an economic expedite process for phase transformation evaluations in steels when subjected to weld thermal cycles as well as to draw continuous cooling transformation (CCT diagrams. Different approaches for the simulation and parameter settings have been used by several researchers, yet leading to not always even results. Thus, it was proposed a round-robin test trial performed by different laboratories, aiming to evidence potential sources of error or inadequacy of the approaches. A High Strength Low Alloy (HSLA steel was used as a case study. Despite the limited number of tests, the results show low robustness when comparing the outcomes from the different laboratories and point out for the need to take three actions. The first one is to implement a cooperative and multi-institutional program to assess the effect of relevant simulation parameters, such as the heating rate and holding time at peak temperature, on the final microstructure and transformation temperatures as well as on the hardness for a given cooling rate. The second is to propose calibration procedures for the simulation and measurement systems. The third action is to stimulate experts in this area to develop a guideline of terminology for constituents in the heat affected zone of ferritic steels.

  15. Altered cell wall disassembly during ripening of Cnr tomato fruit : implications for cell wall adhesion and fruit softening

    NARCIS (Netherlands)

    Orfila, C.; Huisman, M.M.H.; Willats, W.G.T.; Alebeek, van G.J.W.M.; Schols, H.A.; Seymour, G.B.; Knox, J.P.

    2002-01-01

    The Cnr (Colourless non-ripening) tomato (Lycopersicon esculentum Mill.) mutant has an aberrant fruit-ripening phenotype in which fruit do not soften and have reduced cell adhesion between pericarp cells. Cell walls from Cnr fruit were analysed in order to assess the possible contribution of pectic

  16. 40 CFR 141.564 - My system practices lime softening-is there any special provision regarding my individual filter...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false My system practices lime softening-is... People Individual Filter Turbidity Requirements § 141.564 My system practices lime softening—is there any special provision regarding my individual filter turbidity monitoring? If your system utilizes...

  17. Lowering the sensory threshold and enhancing the responsivity of biomimetic hair flow sensors by electrostatic spring softening

    NARCIS (Netherlands)

    Droogendijk, H.; Bruinink, C.M.; Sanders, Remco G.P.; Siebelder, Ortwin G.; Krijnen, Gijsbertus J.M.

    2011-01-01

    We report improvements in detection limit and responsivity of biomimetic hair flow sensors by electrostatic spring-softening (ESS). Applying a DC voltage to our capacitive flow sensors results in a reduced sensory threshold, which gives an improvement for the flow detection limit of more than 30%.

  18. QTL dynamics for fruit firmness and softening around an ethyle-dependent polygalacturonase gene in apple (Malus domestica Borkh.).

    NARCIS (Netherlands)

    Costa, F.; Peace, C.P.; Stella, S.; Serra, S.; Musacchi, S.; Bazzani, M.; Sansavini, S.; Weg, van de W.E.

    2010-01-01

    Apple fruit are well known for their storage life, although a wide range of flesh softening occurs among cultivars. Loss of firmness is genetically coordinated by the action of several cell wall enzymes, including polygalacturonase (PG) which depolymerizes cell wall pectin. By the analysis of ‘Fuji’

  19. Model-based prediction of fluid bed state in full-scale drinking water pellet softening reactors

    NARCIS (Netherlands)

    Kramer, O.; Jobse, M.A.; Baars, E.T.; van der Helm, A.W.C.; Colin, M.G.; Kors, L...J...; van Vugt, W.H.

    2015-01-01

    Softening at drinking water treatment plants is often realised by fluidised bed pellet reactors. Generally, sand is used as seeding material and pellets are produced as a by-product. To improve to sustainability, research has been carried out to replace the seeding material by re-using grained and s

  20. Elektif Kolonoskopi Öncesi Uygulanan Kolon Hazırlığı Talimatlarına Hastaların Uyumu; Anket Çalışması

    OpenAIRE

    Çakır, Tuğrul; Aslaner, Arif; Mayir, Burhan; Doğan, Uğur; Gündüz, Umut Rıza; Koşar, Mehmet Nuri; Oruç, Mehmet Tahir

    2016-01-01

    Amaç: Kolorektal hastalıklarının tanı ve tedavisi için kolonoskopi işlemi öncesi barsak hazırlığının yeterli olması çok önemlidir. Biz bu çalışmada; kolonoskopi işlemi öncesinde oral ve lavman yoluyla sağlanan kolon temizliğinin etkinliğini ve hastaların uyumunu değerlendirilmeyi amaçladık. Yöntemler: Çalışmaya kolonoskopi planlanan ve 250 ml Sennozit A-B ve kalsiyum tuzunu içeren solüsyon ve 210 ml sodyum hidrojen fosfat içerikli lavman ile barsak hazırlığı yapılan...

  1. Statistical Approach to Optimize the Process Parameters of HAZ of Tool Steel EN X32CrMoV12-28 after Die-Sinking EDM with SF-Cu Electrode

    Directory of Open Access Journals (Sweden)

    L’uboslav Straka

    2017-01-01

    Full Text Available The paper describes the results of the experimental research of the heat affected zone (HAZ of an eroded surface after die-sinking electrical discharge machining (EDM. The research was carried out on chrome-molybdenum-vanadium alloyed tool steel EN X32CrMoV12-28 (W.-Nr. 1.2365 after die-sinking EDM with a SF-Cu electrode. The aim of the experimental measurements was to contribute to the database of knowledge that characterizes the significant impact of the main technological and process parameters on the eroded surface properties during die-sinking EDM. The quality of the eroded surface was assessed from the viewpoint of surface roughness, microhardness variation, and the total HAZ depth of the thin sub-surface layer adjacent to the eroded surface. On the basis of measurement results, mathematical models were established by statistical methods. These models can be applied for computer simulation and prediction of the resultant quality of the machined surface after die-sinking EDM. The results achieved by simulation were compared with the results of experimental measurements and high correlation indexes between the predicted and real values were achieved. Suggested mathematical models can be also applied for the determination of the optimal combination of significant technological parameters in order to minimize microhardness and total HAZ depth variations of tool steel EN X32CrMoV12-28 after die-sinking EDM with a SF-Cu electrode.

  2. Üniversite öğrencilerinin teknolojiye hazır bulunuşluk düzeyi ve kişilik özellikleri arasındaki ilişki: Erciyes Üniversitesi örneği

    OpenAIRE

    Sönmez, Ebru; Akgül, Hanife

    2015-01-01

    Bu çalışmanın amacı, üniversite öğrencilerinin teknolojiye hazır bulunuşluk düzeyi ile kişilik tipleri arasındaki ilişkiyi incelemektir. Öğrencilerinin teknolojiye hazır bulunuşluk düzeylerini ölçmek üzere, Parasuraman tarafından geliştirilen Teknolojiye Hazır Bulunuşluk İndeksini (TRI) temel alarak Yen’in uyarlamış olduğu 18 ifadeden oluşan TRI kullanılmıştır. Bu indekste teknolojiye hazır bulunuşluk düzeyleri “yenilikçilik”, “güvensizlik”, “huzursuzluk” ve “iyimserlik” ol...

  3. Hallazgos radiográficos de connotación endodóntica utilizando tomografía computarizada de haz cónico

    Directory of Open Access Journals (Sweden)

    H. Monardes Cortés

    2015-04-01

    Full Text Available En la práctica de la odontología, la tomografía computarizada de haz cónico (TCHC ha sido utilizada en la indicación de implantes y cirugía maxilofacial. En endodoncia, ya ha comenzado su uso, por la posibilidad de conocer las tres dimensiones del diente. Este estudio busca determinar la frecuencia de las diferentes condiciones patológicas más prevalentes en endodoncia, mediante el uso de TCHC, para lo cual se identificaron y cuantificaron hallazgos radiográficos de connotación endodóntica en 128 TCHC en pacientes chilenos entre 7 y 78 años, de ambos sexos, evaluando un total de 1.213 dientes. Las imágenes fueron obtenidas por un equipo SkyView 3D TCHC Panoramic Imager® 12 bits (MyRay, Imola, Italia, con una exposición de 90 Kvp, 10 mA y observadas mediante el software Skyview viewer manager ver 1.2.0.6 MyRay por 2 observadores previamente calibrados. Se observaron los dientes de manera independiente, en los ejes sagital, coronal y axial con un intervalo de corte de 0,5 mm. Los datos se introdujeron en la versión 17.0 del paquete estadístico SPSS® para Windows (SPSS Inc., Chicago, IL para su análisis. Los hallazgos de connotación endodóntica fueron: lesión apical, terapia endodóntica realizada, taurodontismo, canales accesorios, dilaceraciones, ápices abiertos, reabsorción interna, reabsorción externa apical y cervical. Se encontró asociación significativa entre la presencia de lesiones apicales y dientes endodónticamente tratados (p= 0,00.

  4. Natural clinoptilolite composite membranes on tubular stainless steel supports for water softening.

    Science.gov (United States)

    Adamaref, Solmaz; An, Weizhu; Jarligo, Maria Ophelia; Kuznicki, Tetyana; Kuznicki, Steven M

    2014-01-01

    Disk membranes generated from high-purity natural clinoptilolite mineral rock have shown promising water desalination and de-oiling performance. In order to scale up production of these types of membranes for industrial wastewater treatment applications, a coating strategy was devised. A composite mixture of natural clinoptilolite from St. Cloud (Winston, NM, USA) and aluminum phosphate was deposited on the inner surface of porous stainless steel tubes by the slip casting technique. The commercial porous stainless steel tubes were pre-coated with a TiO2 layer of about 10 μm. Phase composition and morphology of the coating materials were investigated using X-ray diffraction and scanning electron microscopy. Water softening performance of the fabricated membranes was evaluated using Edmonton (Alberta, Canada) municipal tap water as feed source. Preliminary experimental results show a high water flux of 7.7 kg/(m(2) h) and 75% reduction of hardness and conductivity in a once-through membrane process at 95 °C and feed pressure of 780 kPa. These results show that natural zeolite coated, stainless steel tubular membranes have high potential for large-scale purification of oil sands steam-assisted gravity drainage water at high temperature and pressure requirements.

  5. Noise-induced chaos and basin erosion in softening Duffing oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Gan Chunbiao [Department of Mechanics, CMEE, Zhejiang University, Hangzhou 310027 (China)] e-mail: cb_gan@zju.edu.cn

    2005-09-01

    It is common for many dynamical systems to have two or more attractors coexist and in such cases the basin boundary is fractal. The purpose of this paper is to study the noise-induced chaos and discuss the effect of noises on erosion of safe basin in the softening Duffing oscillator. The Melnikov approach is used to obtain the necessary condition for the rising of chaos, and the largest Lyapunov exponent is computed to identify the chaotic nature of the sample time series from the system. According to the Melnikov condition, the safe basins are simulated for both the deterministic and the stochastic cases of the system. It is shown that the external Gaussian white noise excitation is robust for inducing the chaos, while the external bounded noise is weak. Moreover, the erosion of the safe basin can be aggravated by both the Gaussian white and the bounded noise excitations, and fractal boundary can appear when the system is only excited by the random processes, which means noise-induced chaotic response is induced.

  6. Deformation, warming and softening of Greenland’s ice by refreezing meltwater

    Science.gov (United States)

    Bell, Robin E.; Tinto, Kirsteen; Das, Indrani; Wolovick, Michael; Chu, Winnie; Creyts, Timothy T.; Frearson, Nicholas; Abdi, Abdulhakim; Paden, John D.

    2014-07-01

    Meltwater beneath the large ice sheets can influence ice flow by lubrication at the base or by softening when meltwater refreezes to form relatively warm ice. Refreezing has produced large basal ice units in East Antarctica. Bubble-free basal ice units also outcrop at the edge of the Greenland ice sheet, but the extent of refreezing and its influence on Greenland’s ice flow dynamics are unknown. Here we demonstrate that refreezing of meltwater produces distinct basal ice units throughout northern Greenland with thicknesses of up to 1,100 m. We compare airborne gravity data with modelled gravity anomalies to show that these basal units are ice. Using radar data we determine the extent of the units, which significantly disrupt the overlying ice sheet stratigraphy. The units consist of refrozen basal water commonly surrounded by heavily deformed meteoric ice derived from snowfall. We map these units along the ice sheet margins where surface melt is the largest source of water, as well as in the interior where basal melting is the only source of water. Beneath Petermann Glacier, basal units coincide with the onset of fast flow and channels in the floating ice tongue. We suggest that refreezing of meltwater and the resulting deformation of the surrounding basal ice warms the Greenland ice sheet, modifying the temperature structure of the ice column and influencing ice flow and grounding line melting.

  7. X-ray softening during the 2008 outburst of XTE J1810-189

    CERN Document Server

    Weng, Shan-Shan; Yi, Shu-Xu; Rong, Yu; Gao, Xu-Dong

    2015-01-01

    XTE J1810-189 underwent an outburst in 2008, and was observed over $\\sim 100$ d by RXTE. Performing a time-resolved spectral analysis on the photospheric radius expansion burst detected on 2008 May 4, we obtain the source distance in the range of 3.5--8.7 kpc for the first time. During its outburst, XTE J1810-189 did not enter into the high/soft state, and both the soft and hard colours decreased with decreasing flux. The fractional rms remained at high values ($\\sim 30$ per cent). The RXTE/PCA spectra for 3-25 keV can be described by an absorbed power-law component with an additional Gaussian component, and the derived photon index $\\Gamma$ increased from $1.84\\pm0.01$ to $2.25\\pm0.04$ when the unabsorbed X-ray luminosity in 3-25 keV dropped from $4\\times10^{36}$ ergs s$^{-1}$ to $6\\times10^{35}$ ergs s$^{-1}$. The relatively high flux, dense observations and broadband spectra allow us to provide strong evidence that the softening behaviour detected in the outburst of XTE J1810-189 originates from the evolut...

  8. Reversible stress softening of collagen based networks from the jumbo squid mantle (Dosidicus gigas).

    Science.gov (United States)

    Torres, F G; Troncoso, O P; Rivas, E R; Gomez, C G; Lopez, D

    2014-04-01

    Dosidicus gigas is the largest and one of the most abundant jumbo squids in the eastern Pacific Ocean. In this paper we have studied the muscle of the mantle of D. gigas (DGM). Morphological, thermal and rheological properties were assessed by means of atomic force microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, differential scanning calorimetry, thermogravimetry and oscillatory rheometry. This study allowed us to assess the morphological and rheological properties of a collagen based network occurring in nature. The results showed that the DGM network displays a nonlinear effect called reversible stress softening (RSS) that has been previously described for other types of biological structures such as naturally occurring cellulose networks and actin networks. We propose that the RSS could play a key role on the way jumbo squids withstand hydrostatic pressure. The results presented here confirm that this phenomenon occurs in a wider number of materials than previously thought, all of them exhibiting different size scales as well as physical conformation.

  9. Positively charged and bipolar layered poly(ether imide) nanofiltration membranes for water softening applications

    Science.gov (United States)

    Gassara, S.; Abdelkafi, A.; Quémener, D.; Amar, R. Ben; Deratani, A.

    2015-07-01

    Poly(ether imide) (PEI) ultrafiltration membranes were chemically modified with branched poly(ethyleneimine) to obtain nanofiltration (NF) membrane Cat PEI with a positive charge in the pH range below 9. An oppositely charged polyelectrolyte layer was deposited on the resulting membrane surface by using sodium polystyrene sulfonate (PSSNa) and sodium polyvinyl sulfonate (PVSNa) to prepare a bipolar layered membrane NF Cat PEI_PSS and Cat PEI_PVS having a negatively charged surface and positively charged pores. Cat PEI exhibited good performance to remove multivalent cations (more than 90% of Ca2+) from single salt solutions except in presence of sulfate ions. Adding an anionic polyelectrolyte layer onto the positively charged surface resulted in a significant enhancement of rejection performance even in presence of sulfate anions. Application of the prepared membranes in water softening of natural complex mixtures was successful for the different studied membranes and a large decrease of hardness was obtained. Moreover, Cat PEI_PSS showed a good selectivity for nitrate removal. Fouling experiments were carried out with bovine serum albumin, as model protein foulant. Cat PEI_PSS showed much better fouling resistance than Cat PEI with a quantitative flux recovery ratio.

  10. Experimental Study on the Softening Characteristics of Sandstone and Mudstone in Relation to Moisture Content

    Directory of Open Access Journals (Sweden)

    Gui-chen Li

    2017-01-01

    Full Text Available The kinetics of fluid-solid coupling during immersion is an important topic of investigation in rock engineering. Two rock types, sandstone and mudstone, are selected in this work to study the correlation between the softening characteristics of the rocks and moisture content. This is achieved through detailed studies using scanning electron microscopy, shear tests, and evaluation of rock index properties during exposure to different moisture contents. An underground roadway excavation is simulated by dynamic finite element modeling to analyze the effect of moisture content on the stability of the roadway. The results show that moisture content has a significant effect on shear properties reduction of both sandstone and mudstone, which must thus be considered in mining or excavation processes. Specifically, it is found that the number, area, and diameter of micropores, as well as surface porosity, increase with increasing moisture content. Additionally, stress concentration is negatively correlated with moisture content, while the influenced area and vertical displacement are positively correlated with moisture content. These findings may provide useful input for the design of underground roadways.

  11. Incomplete restoration of immobilization induced softening of young beagle knee articular cartilage after 50-week remobilization.

    Science.gov (United States)

    Haapala, J; Arokoski, J; Pirttimäki, J; Lyyra, T; Jurvelin, J; Tammi, M; Helminen, H J; Kiviranta, I

    2000-01-01

    The aim of this study was to characterize the biomechanical and structural changes in canine knee cartilage after an initial 11-week immobilization and subsequent remobilization period of 50 weeks. Cartilage from the immobilized and remobilized knee was compared with the tissue from age-matched control animals. Compressive stiffness, in the form of instant shear modulus (ISM) and equilibrium shear modulus (ESM) of articular cartilage, was investigated using an in situ indentation creep technique. The local variations in cartilage of glycosaminoglycan (GAG) concentration were measured with a microspectrophotometer after safranin O staining of histological sections. Using a computer-based quantitative polarized light microscopy method, collagen-related optical retardation, gamma, of cartilage zones were performed to investigate the collagen network of cartilage. Macroscopically, cartilage surfaces of the knee joint remained intact both after immobilization and remobilization periods. Immobilization caused significant softening of the lateral femoral and tibial cartilages, as expressed by ESM (up to 30%, p test points. The changes of ESM were positively correlated with the alterations in GAG content of the superficial and deep zones after immobilization and remobilization. This confirms the key role of protoglycans in the regulation of the equilibrium stiffness of articular cartilage. As a conclusion, immobilization of the joint of a young individual may cause long-term, if not permanent, alterations of cartilage biomechanical properties. This may predispose joint to degenerative changes later in life.

  12. An active head-neck model in whole-body vibration: vibration magnitude and softening.

    Science.gov (United States)

    Rahmatalla, Salam; Liu, Ye

    2012-04-05

    An active head-neck model is introduced in this work to predict human-dynamic response to different vibration magnitudes during fore-aft whole-body vibration. The proposed model is a rigid-link dynamic system augmented with passive spring-damper tissue-like elements and additional active dampers that resemble the active part of the muscles. The additional active dampers are functions of the input displacement, velocity, and acceleration and are based on active control theories and a kd-tree data-searching scheme. Five human subjects exposed to random fore-aft vibration with frequency content of 0.5-10 Hz were tested under different vibration with magnitudes of 0.46 m/s(2), 1.32 m/s(2), and 1.66 m/s(2) rms. The results showed that the proposed model was able to reasonably capture the softening characteristics of the human head-neck response during fore-aft whole-body vibration of different magnitudes. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Molecular Cloning and Characterization of Fruit Softening Related Gene Mannanase from Banana Fruit

    Institute of Scientific and Technical Information of China (English)

    ZHUANG Jun-ping; SU Jing; CHEN Wei-xin

    2006-01-01

    A 1 250 bp cDNA fragment encoding β-mannanase, named MaMAN, was cloned from banana (Musa spp cv. Baxi) fruit using degenerate primers designed with reference to the conserved nucleic acid sequences of known β-mannanase genes by RT-PCR. Sequence analysis showed that MaMAN cDNA encompassed a 1 085 bp open-reading frame (ORF), encoding a predicted polypeptide of 395 amino acids. Alignment of the deduced amino acid sequence of MaMAN and other putative β-mannanases showed that MaMAN has an identity of 86, 70, 69, 54, and 57%, respectively, to β-mannanases from tomato, lettuce, arabidopsis, carrot and oryza sativa. The catalytic residues: Asn203, Glu204, Glu318 and the active site residues: Arg86, His277, Tyr279, and Trp360, which were strictly conserved in the glycoside hydrolase family 5 to which all 3-mannanases belonged, were found in MaMAN. Semi-quantitative RT-PCR revealed that the level of MaMAN transcript in the pulp increased during banana fruit ripening, suggesting that MaMAN was likely to be involved highly in banana fruit softening.

  14. Pressure sensitive adhesive using light color, low softening point petroleum hydrocarbon resins

    Energy Technology Data Exchange (ETDEWEB)

    Ahner, M.E.

    1987-07-28

    This patent describes an adhesive composition comprising from about 20% to about 80% by weight of a copolymer and, correspondingly, from about 80% to about 20% by weight of a tackifying petroleum hydrocarbon resin having a softening point of from 0/sup 0/C to about 40/sup 0/C. It has a number average molecular weight of from about 100 to about 600, and a Gardner color less than about 7 prepared by the aluminum chloride catalyzed Friedel Crafts polymerization of a hydrocarbon feed comprising: (a) from about 5% to about 75% by weight of C/sub 8/ to C/sub 10/ vinyl aromatic hydrocarbon stream; (b) from about 10% to about 35% by weight of a piperylene concentrate; and (c) from about 25% to about 70% by weight of a C/sub 4/ to C/sub 8/ monoolefin chain transfer agent of the formula RR'C=CHR'' where R and R' are C/sub 1/ to C/sub 5/ alkyl, and R'' is H or C/sub 1/ to C/sub 4/ alkyl group.

  15. Effect of sample preservation on stress softening and permanent set of porcine skin.

    Science.gov (United States)

    Caro-Bretelle, A S; Gountsop, P N; Ienny, P; Leger, R; Corn, S; Bazin, I; Bretelle, F

    2015-09-18

    Skin is a composite material with a complex structure which exhibits a wide range of behaviours such as anisotropy, viscoelasticity, hyperelasticity, plasticity etc. Indeed it remains a great challenge to understand its behaviour as it is involved in many consumer and medical applications. In most studies, experiments are performed in situ or in vitro on fresh tissues but most of the time samples are preserved before testing (fridge, freezer, saline solution etc.). In this paper, the impact of samples conservation on the softening behaviour and on the permanent set is studied in order to select the appropriate conservation protocol. Samples are extracted from several pigs' abdomens (direction parallel to spine) and the mechanical testing consists in loading-unloading uniaxial tension tests instrumented with digital image correlation inducing thus reliable strain measurements in a chosen region of interest. The results of this study revealed that preservation conditions must be carefully chosen; conservation in a saline solution and freezing without any caution alter the irreversible part of the global mechanical behaviour of the tissues.

  16. Nonlinear acoustic propagation in bubbly liquids: Multiple scattering, softening and hardening phenomena.

    Science.gov (United States)

    Doc, Jean-Baptiste; Conoir, Jean-Marc; Marchiano, Régis; Fuster, Daniel

    2016-04-01

    The weakly nonlinear propagation of acoustic waves in monodisperse bubbly liquids is investigated numerically. A hydrodynamic model based on the averaged two-phase fluid equations is coupled with the Rayleigh-Plesset equation to model the dynamics of bubbles at the local scale. The present model is validated in the linear regime by comparing with the Foldy approximation. The analysis of the pressure signals in the linear regime highlights two resonance frequencies: the Minnaert frequency and a multiple scattering resonance that strongly depends on the bubble concentration. For weakly nonlinear regimes, the generation of higher harmonics is observed only for the Minnaert frequency. Linear combinations between the Minnaert harmonics and the multiple scattering resonance are also observed. However, the most significant effect observed is the appearance of softening-hardening effects that share some similarities with those observed for sandstones or cracked materials. These effects are related to the multiple scattering resonance. Downward or upward resonance frequency shifts can be observed depending on the characteristic of the incident wave when increasing the excitation amplitude. It is shown that the frequency shift can be explained assuming that the acoustic wave velocity depends on a law different from those usually encountered for sandstones or cracked materials.

  17. A Combined Softening and Hardening Mechanism for Low Frequency Human Motion Energy Harvesting Application

    Directory of Open Access Journals (Sweden)

    Khalis Suhaimi

    2014-01-01

    Full Text Available This paper concerns the mechanism for harvesting energy from human body motion. The vibration signal from human body motion during walking and jogging was first measured using 3-axes vibration recorder placed at various places on the human body. The measured signal was then processed using Fourier series to investigate its frequency content. A mechanism was proposed to harvest the energy from the low frequency-low amplitude human motion. This mechanism consists of the combined nonlinear hardening and softening mechanism which was aimed at widening the bandwidth as well as amplifying the low human motion frequency. This was realized by using a translation-to-rotary mechanism which converts the translation motion of the human motion into the rotational motion. The nonlinearity in the system was realized by introducing a winding spring stiffness and the magnetic stiffness. Quasi-static and dynamic measurement were conducted to investigate the performance of the mechanism. The results show that, with the right degree of nonlinearity, the two modes can be combined together to produce a wide flat response. For the frequency amplification, the mechanism manages to increase the frequency by around 8 times in terms of rotational speed.

  18. Observation of Low-Temperature Softening of Transverse Elastic Modulus Due to Cobalt Impurities in Mercury Selenide

    Science.gov (United States)

    Zhevstovskikh, Irina V.; Okulov, Vsevolod I.; Gudkov, Vladimir V.; Sarychev, Maksim N.; Medvedev, Kirill A.; Andriichuk, Myroslav D.; Paranchich, Lidiya D.

    2016-12-01

    Influence on elastic moduli of donor electron d-states of cobalt impurities has been investigated in mercury selenide crystals. Experiments have been carried out at the frequency of 53 MHz in the temperature interval of 1.3-100 K. Softening of the (C_{11} - C_{12})/2 modulus below 10 K has been observed in the impurity crystals in contrast with the (C_{11} + C_{12} + 2C_{44})/2 and C_{44} moduli those have exhibited hardening at cooling typical for dielectric and semiconductor crystals. The softening of the elastic modulus has been interpreted as manifestation of hybridization of the impurity d-states in the conduction band of the crystal. Comparison of theoretical calculations with experimental data has been proved to be in good agreement and has made it possible to determine the parameters characterizing the hybridized electron states.

  19. Phonon softening in the CDW systems NbSe{sub 2} and TiSe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Hott, Roland; Heid, Rolf; Bohnen, Klaus-Peter [Karlsruhe Institute of Technology, Institute of Solid State Physics, Karlsruhe (Germany); Weber, Frank; Castellan, John-Paul [Karlsruhe Institute of Technology, Institute of Solid State Physics, Karlsruhe (Germany); Materials Science Division, Argonne National Laboratory, Argonne, IL (United States); Rosenkranz, Stephan; Osborn, Raymond [Materials Science Division, Argonne National Laboratory, Argonne, IL (United States); Egami, Takeshi [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN (United States); Said, Ayman [Advanced Photon Source, Argonne National Laboratory, Argonne, IL (United States); Reznik, Dmitry [Karlsruhe Institute of Technology, Institute of Solid State Physics, Karlsruhe (Germany); Department of Physics, University of Colorado at Boulder, Boulder, CO (United States)

    2013-07-01

    We present new results on the soft-mode behaviour of phonons in the Charge Density Wave (CDW) systems NbSe{sub 2} and TiSe{sub 2}. Our theoretical predictions from Density Functional Theory (DFT) based on ab-initio phonon calculations coincide with the CDW instability behaviour that we observed experimentally by means of high resolution Inelastic X-ray Scattering (IXS). While TiSe{sub 2} shows a rather sharp phonon anomaly at T=190 K, the anomaly in NbSe{sub 2} at T=33 K is much broader than expected for a Fermi surface nesting driven CDW instability. For NbSe{sub 2}, we exclude Fermi surface nesting as main origin of the phonon softening. For TiSe{sub 2}, the phonon softening seems to be well described within the framework of DFT.

  20. Altered cell wall disassembly during ripening of Cnr tomato fruit: implications for cell adhesion and fruit softening

    DEFF Research Database (Denmark)

    Orfila, C.; Huisman, M.M.H.; Willats, William George Tycho

    2002-01-01

    polysaccharides to the non-softening and altered cell adhesion phenotype. Cell wall material (CWM) and solubilised fractions of mature green and red ripe fruit were analysed by chemical, enzymatic and immunochemical techniques. No major differences in CWM sugar composition were detected although differences were...... that was chelator-soluble was 50% less in Cnr cell walls at both the mature green and red ripe stages. Chelator-soluble material from ripe-stage Cnr was more susceptible to endo-polygalacturonase degradation than the corresponding material from wild-type fruit. In addition, cell walls from Cnr fruit contained......The Cnr (Colourless non-ripening) tomato (Lycopersicon esculentum Mill.) mutant has an aberrant fruit-ripening phenotype in which fruit do not soften and have reduced cell adhesion between pericarp cells. Cell walls from Cnr fruit were analysed in order to assess the possible contribution of pectic...

  1. A randomised controlled trial of ion-exchange water softeners for the treatment of eczema in children.

    Directory of Open Access Journals (Sweden)

    Kim S Thomas

    2011-02-01

    Full Text Available Epidemiological studies and anecdotal reports suggest a possible link between household use of hard water and atopic eczema. We sought to test whether installation of an ion-exchange water softener in the home can improve eczema in children.This was an observer-blind randomised trial involving 336 children (aged 6 months to 16 years with moderate/severe atopic eczema. All lived in hard water areas (≥200 mg/l calcium carbonate. Participants were randomised to either installation of an ion-exchange water softener plus usual eczema care, or usual eczema care alone. The primary outcome was change in eczema severity (Six Area Six Sign Atopic Dermatitis Score, SASSAD at 12 weeks, measured by research nurses who were blinded to treatment allocation. Analysis was based on the intent-to-treat population. Eczema severity improved for both groups during the trial. The mean change in SASSAD at 12 weeks was -5.0 (20% improvement for the water softener group and -5.7 (22% improvement for the usual care group (mean difference 0.66, 95% confidence interval -1.37 to 2.69, p = 0.53. No between-group differences were noted in the use of topical corticosteroids or calcineurin inhibitors.Water softeners provided no additional benefit to usual care in this study population. Small but statistically significant differences were found in some secondary outcomes as reported by parents, but it is likely that such improvements were the result of response bias, since participants were aware of their treatment allocation. A detailed report for this trial is also available at http://www.hta.ac.uk.Current Controlled Trials ISRCTN71423189 Please see later in the article for the Editors' Summary.

  2. QTL dynamics for fruit firmness and softening around an ethylene-dependent polygalacturonase gene in apple (Malus x domestica Borkh.).

    Science.gov (United States)

    Costa, Fabrizio; Peace, Cameron P; Stella, Sara; Serra, Sara; Musacchi, Stefano; Bazzani, Micaela; Sansavini, Silviero; Van de Weg, W Eric

    2010-06-01

    Apple fruit are well known for their storage life, although a wide range of flesh softening occurs among cultivars. Loss of firmness is genetically coordinated by the action of several cell wall enzymes, including polygalacturonase (PG) which depolymerizes cell wall pectin. By the analysis of 'Fuji' (Fj) and 'Mondial Gala' (MG), two apple cultivars characterized by a distinctive ripening behaviour, the involvement of Md-PG1 in the fruit softening process was confirmed to be ethylene dependent by its transcript being down-regulated by 1-methylcyclopropene treatment in MG and in the low ethylene-producing cultivar Fj. Comparing the PG sequence of MG and Fj, a single nucleotide polymorphism (SNP) was discovered. Segregation of the Md-PG1(SNP) marker within a full-sib population, obtained by crossing Fj and MG, positioned Md-PG1 in the linkage group 10 of MG, co-located with a quantitative trait locus (QTL) identified for fruit firmness in post-harvest ripening. Fruit firmness and softening analysed in different stages, from harvest to post-storage, determined a shift of the QTL from the top of this linkage group to the bottom, where Md-ACO1, a gene involved in ethylene biosynthesis in apple, is mapped. This PG-ethylene-related gene has beeen positioned in the apple genome on chromosome 10, which contains several QTLs controlling fruit firmness and softening, and the interplay among the allelotypes of the linked loci should be considered in the design of a marker-assisted selection breeding scheme for apple texture.

  3. Circular economy in drinking water treatment: reuse of ground pellets as seeding material in the pellet softening process.

    Science.gov (United States)

    Schetters, M J A; van der Hoek, J P; Kramer, O J I; Kors, L J; Palmen, L J; Hofs, B; Koppers, H

    2015-01-01

    Calcium carbonate pellets are produced as a by-product in the pellet softening process. In the Netherlands, these pellets are applied as a raw material in several industrial and agricultural processes. The sand grain inside the pellet hinders the application in some high-potential market segments such as paper and glass. Substitution of the sand grain with a calcite grain (100% calcium carbonate) is in principle possible, and could significantly improve the pellet quality. In this study, the grinding and sieving of pellets, and the subsequent reuse as seeding material in pellet softening were tested with two pilot reactors in parallel. In one reactor, garnet sand was used as seeding material, in the other ground calcite. Garnet sand and ground calcite performed equally well. An economic comparison and a life-cycle assessment were made as well. The results show that the reuse of ground calcite as seeding material in pellet softening is technologically possible, reduces the operational costs by €38,000 (1%) and reduces the environmental impact by 5%. Therefore, at the drinking water facility, Weesperkarspel of Waternet, the transition from garnet sand to ground calcite will be made at full scale, based on this pilot plant research.

  4. On the Rule of Mixtures for Predicting Stress-Softening and Residual Strain Effects in Biological Tissues and Biocompatible Materials

    Directory of Open Access Journals (Sweden)

    Alex Elías-Zúñiga

    2014-01-01

    Full Text Available In this work, we use the rule of mixtures to develop an equivalent material model in which the total strain energy density is split into the isotropic part related to the matrix component and the anisotropic energy contribution related to the fiber effects. For the isotropic energy part, we select the amended non-Gaussian strain energy density model, while the energy fiber effects are added by considering the equivalent anisotropic volumetric fraction contribution, as well as the isotropized representation form of the eight-chain energy model that accounts for the material anisotropic effects. Furthermore, our proposed material model uses a phenomenological non-monotonous softening function that predicts stress softening effects and has an energy term, derived from the pseudo-elasticity theory, that accounts for residual strain deformations. The model’s theoretical predictions are compared with experimental data collected from human vaginal tissues, mice skin, poly(glycolide-co-caprolactone (PGC25 3-0 and polypropylene suture materials and tracheal and brain human tissues. In all cases examined here, our equivalent material model closely follows stress-softening and residual strain effects exhibited by experimental data.

  5. Softening and Mineral Content of Cassava (Manihot esculenta Crantz Leaves During the Fermentation to Produce Ntoba mbodi

    Directory of Open Access Journals (Sweden)

    S. Mokemiabeka

    2011-12-01

    Full Text Available The aim of study is to investigate the softening of cassava leaves during the fermentation of Ntoba mbodi and the mineral content of cassava leaves fermented and unfermented. The softening of cassava leaves is a characteristic of fermentation to produce Ntoba mbodi. It is due to an enzymatic process. The activity of cellulase and polygalacturonase enzymes, very weak at the beginning of fermentation, increases sharply in 24 h and decreases thereafter. The pectinesterase and pectin lyase activity, already present at the beginning of fermentation, reaches the maximum after 24 h of fermentation for pectinesterase and 48 h for pectin lyase. The cellulase is mainly of microbial origin. The cassava leaves softening is gradual and becomes maximum at the end of fermentation. It is accompanied by a loss of water leading to a decrease in protein and magnesium content. The Ntoba mbodi is richer in ash than fresh cassava leaves. Although Ntoba mbodi is a vegetable rich in minerals, its sodium content is low. Thus, Ntoba mbodi can be recommended for a meal without peril.

  6. Improvement of 3D Polyester Fabric Surface with Nano Beta-Cyclodextrin and Hydrophilic Silicone and Microemulsion Softeners

    Directory of Open Access Journals (Sweden)

    M. M. Jolaei

    2016-12-01

    Full Text Available Modifying of polyester spacer fabric by β-Cyclodextrin may create new characteristics in the product. Using different siloxane including amino ethyl amino propyl polydimethylsiloxane and polyether amino functional siloxane can produce appropriate softness and lead to relative stability of β-CD on polyester fabric. In this research different concentration of siloxane compounds as a softener, and β- CD as a modifier are applied and some of the properties of the fabric including weight change, regain, water drop absorption time on fabric surface, chrome ion absorption and reactive dye absorption are studied. Also morphology of fabric surface has been examined by SEM images and chemical structure by FT-IR. We have also studied washing durability of the modified product after 10 times of washing. The results show that increasing of concentration of softener and β-CD leads to obtain a higher gain modification. In comparison of two different based softeners the amino ethyl amino propyl polydimethylsiloxane (AEAP- Silicon indicates a better durability than the polyether amino functional siloxane (PEA-Silicon.

  7. Normal and Fibrotic Rat Livers Demonstrate Shear Strain Softening and Compression Stiffening: A Model for Soft Tissue Mechanics.

    Science.gov (United States)

    Perepelyuk, Maryna; Chin, LiKang; Cao, Xuan; van Oosten, Anne; Shenoy, Vivek B; Janmey, Paul A; Wells, Rebecca G

    2016-01-01

    Tissues including liver stiffen and acquire more extracellular matrix with fibrosis. The relationship between matrix content and stiffness, however, is non-linear, and stiffness is only one component of tissue mechanics. The mechanical response of tissues such as liver to physiological stresses is not well described, and models of tissue mechanics are limited. To better understand the mechanics of the normal and fibrotic rat liver, we carried out a series of studies using parallel plate rheometry, measuring the response to compressive, extensional, and shear strains. We found that the shear storage and loss moduli G' and G" and the apparent Young's moduli measured by uniaxial strain orthogonal to the shear direction increased markedly with both progressive fibrosis and increasing compression, that livers shear strain softened, and that significant increases in shear modulus with compressional stress occurred within a range consistent with increased sinusoidal pressures in liver disease. Proteoglycan content and integrin-matrix interactions were significant determinants of liver mechanics, particularly in compression. We propose a new non-linear constitutive model of the liver. A key feature of this model is that, while it assumes overall liver incompressibility, it takes into account water flow and solid phase compressibility. In sum, we report a detailed study of non-linear liver mechanics under physiological strains in the normal state, early fibrosis, and late fibrosis. We propose a constitutive model that captures compression stiffening, tension softening, and shear softening, and can be understood in terms of the cellular and matrix components of the liver.

  8. On the Rule of Mixtures for Predicting Stress-Softening and Residual Strain Effects in Biological Tissues and Biocompatible Materials

    Science.gov (United States)

    Elías-Zúñiga, Alex; Baylón, Karen; Ferrer, Inés; Serenó, Lídia; Garcia-Romeu, Maria Luisa; Bagudanch, Isabel; Grabalosa, Jordi; Pérez-Recio, Tania; Martínez-Romero, Oscar; Ortega-Lara, Wendy; Elizalde, Luis Ernesto

    2014-01-01

    In this work, we use the rule of mixtures to develop an equivalent material model in which the total strain energy density is split into the isotropic part related to the matrix component and the anisotropic energy contribution related to the fiber effects. For the isotropic energy part, we select the amended non-Gaussian strain energy density model, while the energy fiber effects are added by considering the equivalent anisotropic volumetric fraction contribution, as well as the isotropized representation form of the eight-chain energy model that accounts for the material anisotropic effects. Furthermore, our proposed material model uses a phenomenological non-monotonous softening function that predicts stress softening effects and has an energy term, derived from the pseudo-elasticity theory, that accounts for residual strain deformations. The model’s theoretical predictions are compared with experimental data collected from human vaginal tissues, mice skin, poly(glycolide-co-caprolactone) (PGC25 3-0) and polypropylene suture materials and tracheal and brain human tissues. In all cases examined here, our equivalent material model closely follows stress-softening and residual strain effects exhibited by experimental data. PMID:28788466

  9. Investigation into a new softening agent for use on formalin-fixed, paraffin wax-embedded tissue.

    Science.gov (United States)

    Orchard, G E; Torres, J; Poirier, A; Sounthararajah, R; Webster, J; Notini, L; Hacker, L; Ismail, F; Nwokie, T; Humphrey, P; Spigler, E; Missaghian-Cully, S; Brewer, C; Meredith-Jones, A

    2009-01-01

    The use of tissue softening agents to improve microtomy of keratotic tissues is employed widely. Many of these softeners contain hazardous constituents such as phenol. In this study, the use of non-ionic surfactants or non-toxic ingredients are investigated with the aim of creating a new softening agent. The new agent should be more effective in facilitating the sectioning of hardened tissue while reducing toxicity and complications associated with sectioning hard tissue compared to a commercially available phenol-based formulation. Four formulations are compared against the commercial product for their capability to section routinely processed paraffin-embedded tissue under standard operating procedure parameters. The trial formulations were shown to be fast acting and enabled improved serial sectioning of hard keratotic tissue in nearly all the cases tested. There was no evidence of adverse staining using either tinctorial or immunohistochemical methods. The new formulations had advantages over the commercially available solutions, improving on the number and quality of sections attainable from the tissue blocks, as well as offering a composition less toxic than phenol-based products.

  10. Cyclic softening as a parameter for prediction of remnant creep rupture life of a Indian reduced activation ferritic–martensitic (IN-RAFM) steel subjected to fatigue exposures

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Aritra, E-mail: aritra@igcar.gov.in [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India); Vijayanand, V.D.; Shankar, Vani; Parameswaran, P.; Sandhya, R.; Laha, K.; Mathew, M.D.; Jayakumar, T. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India); Rajendrakumar, E. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat (India)

    2014-12-15

    Sequential fatigue-creep tests were conducted on Indian reduced activation ferritic–martensitic steel at 823 K leading to sharp decrease in residual creep life with increase in prior fatigue exposures. Extensive recovery of martensitic-lath structure taking place during fatigue deformation, manifested as cyclic softening in the cyclic stress response, shortens the residual creep life. Based on the experimental results, cyclic softening occurring during fatigue stage can be correlated with residual creep life, evolving in an empirical model which predicts residual creep life as a function of cyclic softening. Predicted creep lives for specimens pre-cycled at various strain amplitudes are explained on the basis of mechanism of cyclic softening.

  11. Biocompatible water softening system using cationic protein from moringa oleifera extract

    Science.gov (United States)

    Nisha, R. R.; Jegathambal, P.; Parameswari, K.; Kirupa, K.

    2017-07-01

    In developing countries like India, the deciding factors for the selection of the specific water purification system are the flow rate, cost of implementation and maintenance, availability of materials for fabrication or assembling, technical manpower, energy requirement and reliability. But most of them are energy and cost intensive which necessitate the development of cost-effective water purification system. In this study, the feasibility of development of an efficient and cost-effective water purifier using Moringa oleifera cationic protein coated sand column to treat drinking water is presented. Moringa oleifera seeds contain cationic antimicrobial protein which acts as biocoagulant in the removal of turbidity and also aids in water softening. The main disadvantage of using Moringa seeds in water purification is that the dissolved organic matter (DOM) which is left over in the water contributes to growth of any pathogens that come into contact with the stored water. To overcome this limitation, the Moringa oleifera cationic protein coated sand (MOCP c-sand) is prepared in which the flocculant and antimicrobial properties of the MOCP are maintained and the DOM to be rinsed away. The efficiency of MOCP c-sand in removing suspended particles and reducing total hardness (TH), chloride, total dissolved solids (TDS), electrical conductivity (EC) was also studied. Also, it is shown that the functionalized sand showed the same treatment efficiency even after being stored dry and in dehydrated condition for 3 months. This confirms MOCP c-sand's potential as a locally sustainable water treatment option for developing countries since other chemicals used in water purification are expensive.

  12. Evaluation of the impact of lime softening waste disposal in natural environments

    Energy Technology Data Exchange (ETDEWEB)

    Blaisi, Nawaf I.; Roessler, Justin; Cheng, Weizhi [Department of Environmental Engineering Sciences, University of Florida, PO Box 116450, Gainesville, FL 32611-6450 (United States); Townsend, Timothy, E-mail: ttown@ufl.edu [Department of Environmental Engineering Sciences, University of Florida, PO Box 116450, Gainesville, FL 32611-6450 (United States); Al-Abed, Souhail R. [National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268 (United States)

    2015-09-15

    Highlights: • Leaching tests conducted on WTR to assess potential for trace element release. • Aluminum leaching found to be elevated with respect to risk threshold. • Release in anaerobic conditions evaluated with column test run in nitrogen chamber. • Increased release of certain elements seen from residues under anaerobic conditions. • Different leaching tests produced results on two sides of regulatory threshold. - Abstract: Drinking water treatment residues (WTR), generated from the lime softening processes, are commonly reused or disposed of in a number of applications; these include use as a soil amendment or a subsurface fill. Recently questions were posed by the Florida regulatory community on whether lime WTR that contained a small percentage of other treatment additives could appropriately be characterized as lime WTR, in terms of total element content and leachability. A study was done using a broad range of leaching tests, including a framework of tests recently adopted by the United States-Environmental Protection Agency (EPA) and tests that were modified to account for scenario specific conditions, such as the presence of natural organic matter (NOM). The results of these additional leaching tests demonstrated that certain applications, including disposal in a water body with NOM or in placement anaerobic environment, did result in increased leaching of elements such as Fe, and that a site specific assessment should be conducted prior to using WTR in these types of applications. This study illustrates the importance of leaching test selection when attempting to provide an estimation of release in practice. Although leaching tests are just one component in a beneficial use assessment and other factors including aquifer and soil properties play a significant role in the outcome, leaching tests should be tailored to most appropriately represent the scenario or reuse application being evaluated.

  13. Pressure-induced low-lying phonon modes softening and enhanced thermal resistance in β -M g2A l4S i5O18

    Science.gov (United States)

    Li, Yiran; Tian, Zhilin; Luo, Yixiu; Wang, Jiemin; Sun, Luchao; Zheng, Liya; Wang, Jingyang

    2017-02-01

    Lattice thermal conductivities of β -M g2A l4S i5O18 were predicted at various hydrostatic pressures based on some theoretical models. An abnormal decrement on lattice thermal conductivity is observed for compressed crystal structure. A rigorous analysis of structural stability, bonding characteristics, vibration modes, group velocities, and mode Grüneisen parameters helps us to recognize the origin of this anomalous behavior. We attribute the negative dependent trend to the softening of low frequency phonons and strengthening of anharmonicity at elevated pressure, both of which arise from the specific corner-linked tetrahedral framework in the crystal structure. To validate theoretical calculations, we synthesized pure and dense β -M g2A l4S i5O18 ceramic by using a two-step processing method and determined its intrinsic lattice thermal conductivity by successfully eliminating the phonon scattering from defects and high-temperature thermal radiation. The experimental intrinsic values agreed quite well with the theoretical predictions. This paper reports an anomalous pressure-induced reduction of lattice thermal conductivity and also provides a key insight into the interesting phonon modification mechanism through tailoring the crystal structure of complex compounds.

  14. Characterization of major ripening events during softening in grape: turgor, sugar accumulation, abscisic acid metabolism, colour development, and their relationship with growth.

    Science.gov (United States)

    Castellarin, Simone D; Gambetta, Gregory A; Wada, Hiroshi; Krasnow, Mark N; Cramer, Grant R; Peterlunger, Enrico; Shackel, Kenneth A; Matthews, Mark A

    2016-02-01

    Along with sugar accumulation and colour development, softening is an important physiological change during the onset of ripening in fruits. In this work, we investigated the relationships among major events during softening in grape (Vitis vinifera L.) by quantifying elasticity in individual berries. In addition, we delayed softening and inhibited sugar accumulation using a mechanical growth-preventing treatment in order to identify processes that are sugar and/or growth dependent. Ripening processes commenced on various days after anthesis, but always at similarly low elasticity and turgor. Much of the softening occurred in the absence of other changes in berry physiology investigated here. Several genes encoding key cell wall-modifying enzymes were not up-regulated until softening was largely completed, suggesting softening may result primarily from decreases in turgor. Similarly, there was no decrease in solute potential, increase in sugar concentration, or colour development until elasticity and turgor were near minimum values, and these processes were inhibited when berry growth was prevented. Increases in abscisic acid occurred early during softening and in the absence of significant expression of the V. vinifera 9-cis-epoxycarotenoid dioxygenases. However, these increases were coincident with decreases in the abscisic acid catabolite diphasic acid, indicating that initial increases in abscisic acid may result from decreases in catabolism and/or exogenous import. These data suggest that softening, decreases in turgor, and increases in abscisic acid represent some of the earliest events during the onset of ripening. Later, physical growth, further increases in abscisic acid, and the accumulation of sugar are integral for colour development.

  15. Application of the specular and diffuse reflection analysis for in vitro diagnostics of dental erosion: correlation with enamel softening, roughness, and calcium release

    OpenAIRE

    Rakhmatullina, Ekaterina; Bossen, Anke; Höschele, Christoph; Wang, Xiaojie; Beyeler, Barbara; Meier, Christoph; Lussi, Adrian

    2011-01-01

    We present assembly and application of an optical reflectometer for the analysis of dental erosion. The erosive procedure involved acid-induced softening and initial substance loss phases, which are considered to be difficult for visual diagnosis in a clinic. Change of the specular reflection signal showed the highest sensitivity for the detection of the early softening phase of erosion among tested methods. The exponential decrease of the specular reflection intensity with erosive duration w...

  16. Application of the specular and diffuse reflection analysis for in vitro diagnostics of dental erosion: correlation with enamel softening, roughness, and calcium release

    OpenAIRE

    Rakhmatullina, Ekaterina; Bossen, Anke; Höschele, Christoph; Wang, Xiaojie; Beyeler, Barbara; Meier, Christoph; Lussi, Adrian

    2011-01-01

    We present assembly and application of an optical reflectometer for the analysis of dental erosion. The erosive procedure involved acid-induced softening and initial substance loss phases, which are considered to be difficult for visual diagnosis in a clinic. Change of the specular reflection signal showed the highest sensitivity for the detection of the early softening phase of erosion among tested methods. The exponential decrease of the specular reflection intensity with erosive duration w...

  17. Specific Changes of Exocarp and Mesocarp Occurring during Softening Differently Affect Firmness in Melting (MF) and Non Melting Flesh (NMF) Fruits

    OpenAIRE

    Onelli, E.; Ghiani, A.; Gentili, R; S Serra; Musacchi, S.; Citterio, S.

    2015-01-01

    Melting (MF) and non melting flesh (NMF) peaches differ in their final texture and firmness. Their specific characteristics are achieved by softening process and directly dictate fruit shelf life and quality. Softening is influenced by various mechanisms including cell wall reorganization and water loss. In this work, the biomechanical properties of MF Spring Crest's and NMF Oro A's exocarp and mesocarp along with the amount and localization of hydroxycinnamic acids and flavonoids were invest...

  18. Características imaginológicas de la osteosclerosis idiopática de los maxilares evaluada con tomografía computarizada de haz cónico

    OpenAIRE

    Tenorio-Estrada, Janet Kely; Quezada-Marquez, Milushka Miroslava; Evangelista-Alva, Alexis

    2015-01-01

    Objetivo: Determinar las características imaginológicas de la osteoesclerosis idiopática (OI) de los maxilares evaluada con tomografía computarizada de haz cónico (TCHC). Materiales y métodos: Se revisó 454 TCHC bimaxilares del Servicio de Radiología Oral y Maxilofacial de la sede de San Isidro del Posgrado de la Facultad de Estomatología Roberto Beltrán de la Universidad Peruana Cayetano Heredia, periodo 2011-2012. Se analizaron las variables sexo, edad, número, localización, tamaño, forma, ...

  19. Individual and combined effects of relaxin, estrogen, and progesterone in ovariectomized gilts. I. Effects on the growth, softening, and histological properties of the cervix.

    Science.gov (United States)

    Winn, R J; Baker, M D; Sherwood, O D

    1994-09-01

    Marked growth and softening of the uterine portion of the cervix occur during the last third of the 115-day gestation period in the gilt. These changes in the cervix are temporally correlated with elevated blood levels of relaxin, estrogen, and progesterone. We recently demonstrated that relaxin plays a major role in promoting both the growth and softening of the cervix that occur in pregnant gilts. The roles of estrogen and progesterone in these cervical changes remain poorly understood. Accordingly, this study determined the influence of relaxin, estrogen, and progesterone, individually and in combination, on cervical growth and softening in gilts. Fifteen days after ovariectomy, six to nine nonpregnant, sexually mature gilts were assigned to one of the following eight treatment groups: ovariectomized controls, relaxin treated, estrogen treated, progesterone treated, estrogen plus relaxin treated, progesterone plus relaxin treated, estrogen plus progesterone treated, and progesterone plus estrogen plus relaxin treated. Treatment was given for 10 days, with doses of relaxin (0.5 mg, four times daily), estradiol benzoate (1 mg, twice daily), and progesterone (50 mg, twice daily) selected to provide blood levels resembling those between days 100-110 of gestation. The growth, softening, and histological characteristics of the cervices were determined. Treatment with relaxin significantly increased the growth and softening and altered the histological characteristics of the uterine portion of the cervix in the absence of steroid treatment. Estrogen treatment alone increased cervical growth, but when given in combination with relaxin, estrogen did not augment relaxin's ability to increase either cervical growth or softening. Progesterone alone had little or no effect on the growth or softening of the uterine portion of the cervix. Unexpectedly, when given in combination with relaxin, progesterone augmented markedly relaxin's effects on softening and alteration of the

  20. Sculpting the maturation, softening and ethylene pathway: The influences of microRNAs on tomato fruits

    Directory of Open Access Journals (Sweden)

    Zuo Jinhua

    2012-01-01

    Full Text Available Abstract Background MicroRNAs (miRNAs, a ubiquitous class of short RNAs, play vital roles in physiological and biochemical processes in plants by mediating gene silencing at post-transcriptional (PTGS level. Tomato is a model system to study molecular basis of fleshy fruit ripening and senescence, ethylene biosynthesis and signal transduction owing to its genetic and molecular tractability. To study the functions of miRNAs in tomato fruit ripening and senescence, and their possible roles in ethylene response, the next generation sequencing method was employed to identify miRNAs in tomato fruit. Bioinformatics and molecular biology approaches were combined to profile the miRNAs expression patterns at three different fruit ripening stages and by exogenous ethylene treatment. Results In addition to 7 novel miRNA families, 103 conserved miRNAs belonging to 24 families and 10 non-conserved miRNAs matching 9 families were identified in our libraries. The targets of many these miRNAs were predicted to be transcriptional factors. Other targets are known to play roles in the regulation of metabolic processes. Interestingly, some targets were predicted to be involved in fruit ripening and softening, such as Pectate Lyase, beta-galactosidase, while a few others were predicted to be involved in ethylene biosynthesis and signaling pathway, such as ACS, EIN2 and CTR1. The expression patterns of a number of such miRNAs at three ripening stages were confirmed by stem-loop RT-PCR, which showed a strong negative correlation with that of their targets. The regulation of exogenous ethylene on miRNAs expression profiles were analyzed simultaneously, and 3 down-regulated, 5 up-regulated miRNAs were found in this study. Conclusions A combination of high throughput sequencing and molecular biology approaches was used to explore the involvement of miRNAs during fruit ripening. Several miRNAs showed differential expression profiles during fruit ripening, and a number of

  1. Weld heat-affected zone in Ti-6Al-4V alloys. Part 1: Computer simulation of the effect of weld variables on the thermal cycles in the HAZ

    Energy Technology Data Exchange (ETDEWEB)

    Shah, A.K. [Naval Dockyard, Bombay (India). Naval Chemical and Metallurgical Lab.; Kulkarni, S.D.; Gopinathan, V. [Indian Inst. of Technology, Bombay (India). Dept. of Metallurgical Engineering; Krishnan, R. [Gas Turbine Research Establishment, Bangalore (India)

    1995-09-01

    The weld thermal cycles encountered in the HAZ of titanium alloys have been characterized using modified Rosenthal equations. The results are shown in the form of axonometric plots depicting the effect of two weld variables keeping the other variables fixed. Computer simulation results show that the heat input and the plate thickness are the major variables affecting the thermal cycles in the HAZ. The effects of changes in welding speed are reflecting in the variation in the heat input. The electrode radius has minimal effect and can be termed as the minor variable. Preheat or interpass temperatures have an intermediate effect. An increase in electrode radius or decrease in plate thickness requires large apparent displacement of the heat source above the plate surface to be incorporated in the analytical solutions. The melt pool width increases sharply with an increase in the heat input (a/v) or a decrease in plate thickness (d); however, preheat temperature (T{sub 0}) has negligible effect. The effect of weld variables on the effective heat input is also similar. The t{sub 8/5} parameter increases sharply with reducing plate thickness or increasing heat input.

  2. Analysis of xyloglucan endotransglycosylase/hydrolase (XTH genes and diverse roles of isoenzymes during persimmon fruit development and postharvest softening.

    Directory of Open Access Journals (Sweden)

    Ye Han

    Full Text Available Xyloglucan endotransglycosylase/hydrolase (XTH enzymes have played a role in the remodeling of cell wall hemicelluloses. To investigate the function of XTHs in persimmon (Diospyros kaki L. fruit development and postharvest softening, five cDNAs (DkXTH1 to DkXTH5, whose putative proteins contained the conserved DEIDFEFLG motif of XTH, were cloned. Real time quantitative PCR analysis revealed that DkXTH1, DkXTH4, and DkXTH5 peaked in immature expanding fruit, and their higher expression was observed along with higher fruit firmness in cold-treated fruit or firmer cultivar fruit during storage. The opposite gene expression patterns were observed in DkXTH2 and DkXTH3, which reached maxima concomitance with pronounced fruit softening. Meanwhile, the xyloglucan endotransglycosylase (XET enzymes play important roles in both the rapid growth and ripening of persimmon fruit. Furthermore, the recombined DkXTH1 and DkXTH2 proteins showed significant XET activity without any detected XEH activity. However, the XET activity of recombined DkXTH2 protein had a higher affinity for small acceptor molecules than that of recombined DkXTH1 protein. The former might prefer to participate in cell wall restructuring, and the latter is more inclined to participate in cell wall assembly. Besides, DKXTH proteins could function by targeting to the cell wall under regulation of a signal peptide. The data suggested that individual DKXTHs could exhibit different patterns of expression, and the encoded products possessed specific enzymatic properties conferring on their respective functions in growth and postharvest softening of persimmon fruit.

  3. Climate change on Mars and the formation of gullies, lobate debris aprons, and softened craters

    Science.gov (United States)

    Parsons, Reid Allen

    Recent data acquired from spacecraft missions has bettered our understanding of the nature and distribution of ice- and water-related features formed during recent periods of climate change on Mars. Numerical modeling of physical processes constrained by these newly acquired observations is an important tool with which hypotheses relating to the Martian climate can be tested. This work describes the development and implementation of a set of these models focused on the formation of a few young, ice- and water-related features. The subjects of this research are gullies, lobate debris aprons (LDAs), and craters with subdued topography known as "softened" craters. Flow of liquid water and ice over and/or within the Martian surface has been invoked in the formation of these features. Quantifying processes such as fluvial erosion and ice deformation using laboratory experiments is a Rosetta stone with which we can read into the climate history of Mars that is written on its surface. We test the hypothesis that sediment transport on gully slopes occurs via fluvial transport processes by developing a numerical sediment transport model based on steep flume experiments performed by Smart [1984]. At 20° slopes, channels 1 m deep by 8m wide and 0.1 m deep by 3 m wide transport a sediment volume equal to the alcove volume of 6 x 105 m3 in 10 hours and 40 days, respectively, under constant flow conditions. Snowpack melting cannot produce the water discharge rates necessary for fluvial sediment transport, unless long-term (kyr) storage of the resulting meltwater occurs. If these volumes of water are discharged as groundwater, the required aquifer thicknesses and aquifer drawdown lengths would be unrealistically large for a single discharge event. More plausibly, the water volume required by the fluvial transport model could be discharged in ˜ 10 episodes for an aquifer 30 m thick, with a recurrence interval similar to that of Martian obliquity cycles (˜0.1 My). Radar

  4. Effect of loading condition, specimen geometry, size-effect and softening function on double- fracture parameters of concrete

    Indian Academy of Sciences (India)

    Shailendra Kumar; S V Barai

    2012-02-01

    This paper presents numerical investigation of the influence of the specimen geometry, loading condition, size-effect and softening function of concrete on double- fracture parameters. The input data needed for computation of the double- fracture parameters are obtained from the well-known version of Fictitious Crack Model (FCM). FCM is developed for three standard specimens: three-point bend test, compact tension specimen and four-point bend test of size range 100–600 mm at relative size of initial crack length 0.3. The analysis of numerical results shows some interesting behaviour of double- fracture parameters.

  5. EFFECT OF INITIAL GRAIN SIZE ON STATIC RECRYSTALLIZA-TION SOFTENING IN Cr STEEL USING STRESS RELAXATION TECHNIQUE

    Institute of Scientific and Technical Information of China (English)

    A.R. Morgridge

    2002-01-01

    Effect of initial grain size (I.G.S.) on static recrystallization softening in Cr steel(0.77wt.% CR) has been investigated through the use of interrupted hot compressiontests and stress relaxation curves from Gleeble 1500. Initial grain sizes were variedbetween 20 and 93 microns. Stress strains curves for Cr steel for different initialgrain sizes and recrystallization times have been highlighted. Similar observation wasmade for metadynamic recrystallization with shorter retardation times. Staticallyrecrystallized grain size also increased as initial grain size increases. It is found thatthe values of initial grain size have significant effects on the mean flow stress andstatic recrystallization kinetics as well as the peak strain values to initiate dynamicrecrystallization.

  6. Transcriptome Analysis and Ultrastructure Observation Reveal that Hawthorn Fruit Softening Is due to Cellulose/Hemicellulose Degradation

    Science.gov (United States)

    Xu, Jiayu; Zhao, Yuhui; Zhang, Xiao; Zhang, Lijie; Hou, Yali; Dong, Wenxuan

    2016-01-01

    Softening, a common phenomenon in many fruits, is a well coordinated and genetically determined process. However, the process of flesh softening during ripening has rarely been described in hawthorn. In this study, we found that ‘Ruanrou Shanlihong 3 Hao’ fruits became softer during ripening, whereas ‘Qiu JinXing’ fruits remained hard. At late developmental stages, the firmness of ‘Ruanrou Shanlihong 3 Hao’ fruits rapidly declined, and that of ‘Qiu JinXing’ fruits remained essentially unchanged. According to transmission electron microscopy, the middle lamella of ‘Qiu JinXing’ and ‘Ruanrou Shanlihong 3 Hao’ fruit flesh was largely degraded as the fruits matured. Microfilaments in ‘Qiu JinXing’ flesh were arranged close together and were deep in color, whereas those in ‘Ruanrou Shanlihong 3 Hao’ fruit flesh were arranged loosely, partially degraded and light in color. RNA-Seq analysis yielded approximately 46.72 Gb of clean data and 72,837 unigenes. Galactose metabolism and pentose and glucuronate interconversions are involved in cell wall metabolism, play an important role in hawthorn texture. We identified 85 unigenes related to the cell wall between hard- and soft-fleshed hawthorn fruits. Based on data analysis and real-time PCR, we suggest that β-GAL and PE4 have important functions in early fruit softening. The genes Ffase, Gns,α-GAL, PE63, XTH, and CWP, which are involved in cell wall degradation, are responsible for the different textures of hawthorn fruits. Thus, we hypothesize that the different textures of ‘Qiu JinXing’ and ‘Ruanrou Shanlihong 3 Hao’ fruits at maturity mainly result from cellulose/hemicelluloses degradation rather than from lamella degradation. Overall, we propose that different types of hydrolytic enzymes in cells interact to degrade the cell wall, resulting in ultramicroscopic Structure changes in the cell wall and, consequently, fruit softening. These results provide fundamental insight

  7. Transcriptome analysis and ultrastructure observation reveal that hawthorn fruit softening is due to cellulose/hemicellulose degradation

    Directory of Open Access Journals (Sweden)

    Jiayu Xu

    2016-10-01

    Full Text Available Softening, a common phenomenon in many fruits, is a well coordinated and genetically determined process. However, the process of flesh softening during ripening has rarely been described in hawthorn. In this study, we found that ‘Ruanrou Shanlihong 3 Hao’ fruits became softer during ripening, whereas ‘Qiu JinXing’ fruits remained hard. At late developmental stages, the firmness of ‘Ruanrou Shanlihong 3 Hao’ fruits rapidly declined, and that of ‘Qiu JinXing’ fruits remained essentially unchanged. According to transmission electron microscopy (TEM, the middle lamella of ‘Qiu JinXing’ and ‘Ruanrou Shanlihong 3 Hao’ fruit flesh was largely degraded as the fruits matured. Microfilaments in ‘Qiu JinXing’ flesh were arranged close together and were deep in color, whereas those in ‘Ruanrou Shanlihong 3 Hao’ fruit flesh were arranged loosely, partially degraded and light in color. RNA-Seq analysis yielded approximately 46.72 Gb of clean data and 72,837 unigenes. Galactose metabolism and pentose and glucuronate interconversions are involved in cell wall metabolism, play an important role in hawthorn texture. We identified 85 unigenes related to the cell wall between hard- and soft-fleshed hawthorn fruits. Based on data analysis and real-time PCR, we suggest that β-GAL and PE4 have important functions in early fruit softening. The genes Ffase, Gns, α-GAL, PE63, XTH and CWP, which are involved in cell wall degradation, are responsible for the different textures of hawthorn fruits. Thus, we hypothesize that the different textures of ‘Qiu JinXing’ and ‘Ruanrou Shanlihong 3 Hao’ fruits at maturity mainly result from cellulose/hemicelluloses degradation rather than from lamella degradation. Overall, we propose that different types of hydrolytic enzymes in cells interact to degrade the cell wall, resulting in ultramicroscopic Structure changes in the cell wall and, consequently, fruit softening. These results provide

  8. Development of two-step softening heat-treatment in ODS ferritic steel claddings with recrystallized grain structure

    Energy Technology Data Exchange (ETDEWEB)

    Narita, Takeshi; Ukai, Shigeharu; Kaito, Takeji; Ohtsuka, Satoshi [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center; Kobayashi, Toshimi [Sumitomo Metal Technology, Inc., Tokyo (Japan)

    2003-03-01

    Oxide dispersion-strengthened (ODS) ferritic steels have been developed as prospective cladding materials for attaining higher burnup and higher coolant outlet temperature in advanced fast reactors. In the cladding manufacturing process, two-step softening heat-treatment was developed as an effective method for application to the recrystalizing heat-treatment, which made possible the improvement of formability, ductility and the disappearance of strength anisotropy in the ODS ferritic steel claddings. A mass production process is predicted and cost reduction is concomitantly expected for manufacturing ODS ferritic steel claddings with an adequate strength level at 700degC for commercialized fast reactors. (author)

  9. The effects of initial welding temperature and welding parameters on the crystallization behaviors of laser spot welded Zr-based bulk metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Huei-Sen, E-mail: huei@mail.isu.edu.tw [Department of Materials Science and Engineering, I-Shou University, Kaohsiung County 84001, Taiwan (China); Chiou, Mau-Sheng; Chen, Hou-Guang [Department of Materials Science and Engineering, I-Shou University, Kaohsiung County 84001, Taiwan (China); Jang, Jason Shian-Ching [Department of Mechanical Engineering, National Central University, Taoyuan County 32001, Taiwan (China)

    2011-09-15

    This study investigated the effects of the initial welding temperature (IWT) and welding parameters on the crystallization behaviors of laser spot welded (Zr{sub 53}Cu{sub 30}Ni{sub 9}Al{sub 8})Si{sub 0.5} bulk metallic glass (BMG). After the welding process, the microstructure evolution, glass-forming ability (GFA) and mechanical properties of the welded samples were determined by a combination of scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and the Vicker's micro-hardness test. The results showed that the heat-affected zone (HAZ) crystallization seemed avoidable under the room temperature welding process. However, with a combination of a lower energy input (welding Condition C) and a lower IWT (at 0 deg. C), a crystallization-free HAZ was finally obtained. Using the above welding condition into the refined heat flow equation, a critical retention time of 79 ms for the crystallization temperature interval was estimated. Moreover, as the laser welded samples came to crystallization in the HAZ, it was observed that a higher content of spherical-type crystalline precipitates tended to result in a higher value of glass transition temperature, T{sub g}. Therefore, the GFA indices, {Delta}T{sub x}, {gamma} and {gamma}{sub m}, were reduced. Furthermore, it was found that the micro-hardness value in the HAZ crystallization area was decreased due to the massive cracks formed in most parts of the crystalline precipitates. For a crystallization-free HAZ, the hardness seemed unaffected.

  10. Repeated Short-term Spectral Softening in the Low/Hard State of the Galactic Black-Hole Candidate Swift J1753.5-0127

    CERN Document Server

    Yoshikawa, Akifumi; Nakahira, Satoshi; Matsuoka, Masaru; Negoro, Hitoshi; Mihara, Tatehiro; Tamagawa, Toru

    2015-01-01

    We report MAXI and Swift observations of short-term spectral softenings of the galactic black-hole X-ray binary Swift J1753.5-0127 in the low/hard state. These softening events are characterized by a simultaneous increase of soft X-rays (2-4 keV) and a decrease of hard X-rays (15-50 keV) lasting for a few tens of days. The X-ray energy spectra during the softening periods can be reproduced with a model consisting of a multi-color disk blackbody and its Comptonized component. The fraction of the Comptonized component decreased from 0.30 to 0.15 when the spectrum became softer; meanwhile the inner disk temperature (Tin) increased from 0.2 to 0.45 keV. These results imply that the softening events are triggered by a short-term increase of the mass accretion rate. During the observed spectral softening events, the disk flux (F) and Tin did not obey the relation: F is proportional to Tin^4, suggesting that the inner disk radius does not reach the innermost stable circular orbit.

  11. [Adsorption of calcium ion from aqueous solution using Na(+)-conditioned clinoptilolite for hot-water softening].

    Science.gov (United States)

    Zhang, Shuo; Wang, Dong; Chen, Yuan-Chao; Zhang, Xing-Wen; Chen, Gui-Jun

    2015-02-01

    This work investigated adsorptive removal of calcium ion (Ca2+) by virtue of Na(+) -conditioned clinoptilolite simulating the process of softening for industrial hot-water system. Influential factors such as the activation/regeneration of sorbent and solution pH were tested. The kinetics/thermodynamics for adsorption of Ca2+ were analyzed and discussed. Results showed that: (1) The adsorption rate was in good agreement with the pseudo-second order kinetic models, and the process of adsorption better followed the Langmuir model; (2) Higher solution temperature allowed an enhanced efficiency on Ca2+ removal, albeit the maximum adsorption capacity of Na(+)-conditioned clinoptilolite was hardly affected; (3) The process of adsorption was dominated by chemisorption, and also characterized by entropy increase with spontaneous/endothermic nature; (4) Solution temperature was suggested to be controlled within the range of 6 to 10, and more than 9 times of sorbent regeneration could be ensured for an effective adsorption towards Ca2+ with initial concentration less than 20 mg x L(-1). It was demonstrated that the activated clinoptilolite should be a promising alternative adsorbent for industrial hot-water softening.

  12. Magnetic resonance colonography without bowel cleansing using oral and rectal stool softeners (fecal cracking) - a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Ajaj, Waleed; Lauenstein, Thomas C.; Kuehle, Christiane; Herborn, Christoph U.; Goehde, Susanne C. [University Hospital of Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Schneemann, Hubert [University Hospital of Essen, Institute of Pharmacy and Pharmaceutical Sciences, Essen (Germany); Ruehm, Stefan G. [David Geffen School of Medicine at UCLA, Department of Radiology, Los Angeles, CA (United States); Goyen, Mathias [University Hospital of Hamburg-Eppendorf, Medical Center, Hamburg (Germany)

    2005-10-01

    The aim of our study was to assess the effect of oral and rectal stool softeners on dark-lumen magnetic resonance (MR) colonography without bowel cleansing. Ten volunteers underwent MR colonography without colonic cleansing. A baseline examination was performed without oral or rectal administration of stool softeners. In a second set, volunteers ingested 60 ml of lactulose 24 h prior to MR examination. In a third examination, water as a rectal enema was replaced by a solution of 0.5%-docusate sodium (DS). A fourth MR examination was performed, in conjunction with both oral administration of lactulose and rectal application of DS. A T1-weighted data set was acquired at scanning times of 0, 5 and 10 min after colonic filling. A fourth data set was acquired 75 s after i.v. injection of contrast agent. Signal intensity of stool was calculated for all colonic segments. Without oral ingestion of lactulose or rectal enema with DS stool signal intensity was high and did not decrease over time. However, lactulose and DS caused a decrease in stool signal intensity. Both substances together led to a decreasing signal intensity of feces. Combination of lactulose and DS provided the lowest signal intensity of stool. Thus, feces could hardly be distinguished from dark rectal enema allowing for the assessment of the colonic wall. (orig.)

  13. Determinación de la absorción de haz láser en ensayos de refusión en régimen continuo

    Directory of Open Access Journals (Sweden)

    Lima, M.

    1998-04-01

    Full Text Available Not available

    [pt] Este trabalho estuda a absorção do feixe laser sobre a superfície de um ferro fundido branco por meio de ensaios calorimétricos. Um láser de CO2, trabalhando no modo contínuo, foi utilizado para produzir um traço refundido sobre a superfície de um ferro fundido branco em intervalos de velocidade de varredura do feixe entre 0,01 e 1,00 cm/s. O registro da temperatura em função do tempo foi realizada por três termopares fixados à superfície inferior da amostra. Verificou-se que cerva de 13 % da radiação incidente sobre a superfície da amostra é absorvida em forma de calor, para um feixe com 0,65 mm de diâmetro, idependentemente da velocidade de varredura do feixe. No caso do feixe com diâmetro de 1,11 mm, a absorção cai para cerca de 11 %. [es] Se estudia la absorción del rayo láser por la superficie de una fundición blanca utilizando ensayos calorimétricos. Se utilizó un láser tipo CO2 trabajando en modo continuo. Se realizaron trazos refundidos continuos en la superficie de la fundición blanca con velocidad de desplazamiento del haz láser comprendida entre 0,01 y 1,00 cm/s. Para el registro de la temperatura en función del tiempo se utilizaron tres termopares colocados sobre la superficie de la muestra. Se comprobó que, aproximadamente, el 13 % de la radiación incidente sobre la superficie de la muestra es absorbida en forma de calor, para un haz láser de 0,65 mm de diámetro, independientemente de la velocidad de paso del mismo. En el caso del haz láser de 1,11 mm de diámetro, la absorción disminuye a valores próximos al 11 %.

  14. Efecto de los ciclos térmicos sobre la ZAT de una soldadura multipasos de un acero inoxidable superdúplex SAF 2507 Effect of thermal cycles on the HAZ of a stainless steel multipass weld of superduplex SAF 2507

    Directory of Open Access Journals (Sweden)

    D. Villalobos

    2010-09-01

    Full Text Available Los ciclos térmicos de una soldadura multipasos que experimenta un acero inoxidable superdúplex SAF 2507, pueden promover la precipitación de fases secundarias reduciendo significativamente las propiedades mecánicas y la resistencia a la corrosión. Debido a su aplicación en la industria petroquímica, el estudio de las aleaciones superdúplex es de suma importancia para predecir su comportamiento en servicio cuando están involucrados procesos de soldadura por arco eléctrico. En este trabajo, se estudia el cambio microestructural de la zona afectada térmicamente correspondiente al primer cordón depositado de una unión multipasos de acero inoxidable superdúplex SAF 2507 mediante el proceso GTAW y bajo tres temperaturas de interpasos. Los resultados muestran que la temperatura de interpasos tiene una influencia sobre la precipitación de fase sigma en la zona afectada térmicamente del primer cordón depositado.Thermal cycles experienced by a superduplex stainless steel SAF 2507 when is welded, can promote the precipitation of secondary phases which decrease the mechanical properties as well as the corrosion resistance. Due to the application of the duplex alloys in the petrochemical industry, the study of these alloys has become very important in order to predict its service behavior. The aim of this work is to study the microstructural changes in the superduplex stainless steel weld joint after applying the GTAW process under three interpass temperatures after the deposition of every single pass. The results showed that slow cooling rates promoted by the deposition of the subsecuent passes and the higher interpass temperature, promote the precipitation of sigma phase in the HAZ while rapid cooling rates promoted by the lower interpass temperature do not promote the sigma phase precipitation.

  15. Thermal Behavior of an HSLA Steel and the Impact in Phase Transformation: Submerged Arc Welding (SAW) Process Approach to Pipelines

    Science.gov (United States)

    Costa, P. S.; Reyes-Valdés, F. A.; Saldaña-Garcés, R.; Delgado, E. R.; Salinas-Rodríguez, A.

    Heat input during welding metal fusion generates different transformations, such as grain growth, hydrogen cracking, and the formation of brittle structures, generally associated with the heat-affected zone (HAZ). For this reason, it is very important to know the behavior of this area before welding. This paper presents a study of the thermal behavior and its effect on phase transformations in the HAZ, depending on cooling rates (0.1-200 °C/s) to obtain continuous cooling transformation (CCT) curves for an high-strength low-alloy (HSLA) steel. In order to determine the formed phases, optical microscopy and Vickers microhardness measurement were used. The experimental CCT curve was obtained from an HSLA steel, and the results showed that, with the used cooling conditions, the steel did not provide formation of brittle structures. Therefore, it is unlikely that welds made by submerged arc welding (SAW) may lead to hydrogen embrittlement in the HAZ, which is one of the biggest problems of cracking in gas conduction pipelines. In addition, with these results, it will be possible to control the microstructure to optimize the pipe fabrication with SAW process in industrial plants.

  16. El uso de fotocélulas de haz simple y doble para medir la velocidad en carreras®. The use of single- and dual-beam photocells to measure the sprint time®.

    Directory of Open Access Journals (Sweden)

    Juan García-López

    2012-10-01

    Full Text Available ResuemnEl objetivo del estudio fue analizar la influencia de la tecnología de las fotocélulas en el registro de tiempo y su fiabilidad durante de carreras de velocidad de corta distancia. Participaron 25 estudiantes (20.5±0.5 años; 1.78±0.02 m; 77.5±1.8 kg que fueron evaluados en 3 días (2 de familiarización y 1 de test. Se registraron aleatoriamente 3 carreras de aceleración y 3 velocidad lanzada, cronometradas simultáneamente a los 5, 10 y 15 m por dos sistemas de fotocélulas DSD Laser System®: haz simple y doble haz. El tipo de fotocélulas utilizadas influyó en el tiempo de carrera (F=11.92 y p 0.80 a los 10 y 5 m, respectivamente. En la carrera lanzada ambos sistemas midieron prácticamente igual (diferencias de ~0.005 s, obteniendo registros fiables a los 15 y 10 m, respectivamente. En conclusión, en carreras de aceleración la distancia mínima a registrar con haz simple debe ser de 10 m, y de 5 m con haz doble, mientras que en carreras lanzadas deberían utilizarse unas distancias mínimas de 15 y 10 m, respectivamente. Futuros estudios deberían analizar la distancia óptima a la primera fotocélula en las carreras de aceleración, para aumentar la fiabilidad de la medición y facilitar la comparación entre registros de diferentes estudios.AbstractThe purpose was to analyze the influence of the timing gates’ technology on both running time performance and its reliability during short sprint distances. Twenty-five physical students participated (20.5±0.5 yr; 1.78±0.02 m; 77.5±1.8 kg, whose were evaluated during 3 separate days (2 familiarization sessions and 1 testing session. Three standing-start and 3 flying-start runs were randomized and simultaneously registered at 5, 10 and 15 m by two timing gates DSD Laser System®: single- and dual-beam. The type of timing gates affected the performance (F=11.92 y p0.80 at the distances of 10 and 5 m, respectively. During the flying-start runs, both systems obtained a very

  17. HAZ microstructure in joints made of X13CrMoCoVNbNB9-2-1 (PB2 steel welded with and without post-weld heat treatment

    Directory of Open Access Journals (Sweden)

    M. Łomozik

    2016-07-01

    Full Text Available The article presents the results of research butt welded joints made of X13CrMoCoVNbNB9-2-1 steel. The joints were welded with post-weld heat treatment PWHT and without PWHT, using the temper bead technique TBT. After welding the joint welded with PWHT underwent stress-relief annealing at 770 °C for 3 hours. The scope of structural tests included the microstructural examination of the coarse-grained heat affected zone (HAZ areas of the joints, the comparison of the morphology of these areas and the determination of carbide precipitate types of the coarse grain heat affected zone (CGHAZ of the joints welded with and without PWHT.

  18. Static Softening in a Ni-30Fe Austenitic Model Alloy After Hot Deformation: Microstructure and Texture Evolution

    Science.gov (United States)

    Beladi, Hossein; Cizek, Pavel; Taylor, Adam S.; Rohrer, Gregory S.; Hodgson, Peter D.

    2017-02-01

    In the current study, the microstructure and texture characteristics of a model Ni-30Fe austenitic alloy were investigated during hot deformation and subsequent isothermal holding. The deformation led to the formation of self-screening arrays of microbands within a majority of grains. The microbands characteristics underwent rather modest changes during the post-deformation annealing, which suggests that limited dislocation annihilation occurs within the corresponding dislocation walls. The fraction of statically recrystallized (SRX) grains progressively increased with the holding time and closely matched the softening fraction measured from the offset flow stress approach. The corresponding texture was weak and preserved its character with the holding time. There was no pronounced temperature effect on the grain boundary character distribution after the completion of SRX. The Σ3 and Σ9 coincidence site lattice boundaries were characterized as (111) pure twist and (1-14) symmetric tilt types, respectively. Nonetheless, the recrystallization temperature slightly affected the grain boundary network.

  19. Effect of water treatment additives on lime softening residual trace chemical composition--implications for disposal and reuse.

    Science.gov (United States)

    Cheng, Weizhi; Roessler, Justin; Blaisi, Nawaf I; Townsend, Timothy G

    2014-12-01

    Drinking water treatment residues (WTR) offer potential benefits when recycled through land application. The current guidance in Florida, US allows for unrestricted land application of lime softening WTR; alum and ferric WTR require additional evaluation of total and leachable concentrations of select trace metals prior to land application. In some cases a mixed WTR is produced when lime softening is accompanied by the addition of a coagulant or other treatment chemical; applicability of the current guidance is unclear. The objective of this research was to characterize the total and leachable chemical content of WTR from Florida facilities that utilize multiple treatment chemicals. Lime and mixed lime WTR samples were collected from 18 water treatment facilities in Florida. Total and leachable concentrations of the WTR were measured. To assess the potential for disposal of mixed WTR as clean fill below the water table, leaching tests were conducted at multiple liquid to solid ratios and under reducing conditions. The results were compared to risk-based soil and groundwater contamination thresholds. Total metal concentrations of WTR were found to be below Florida soil contaminant thresholds with Fe found in the highest abundance at a concentration of 3600 mg/kg-dry. Aluminum was the only element that exceeded the Florida groundwater contaminant thresholds using SPLP (95% UCL = 0.23 mg/L; risk threshold = 0.2 mg/L). Tests under reducing conditions showed elevated concentrations of Fe and Mn, ranging from 1 to 3 orders of magnitude higher than SPLP leachates. Mixed lime WTR concentrations (total and leachable) were lower than the ferric and alum WTR concentrations, supporting that mixed WTR are appropriately represented as lime WTR. Testing of WTR under reducing conditions demonstrated the potential for release of certain trace metals (Fe, Al, Mn) above applicable regulatory thresholds; additional evaluation is needed to assess management options where

  20. 有机硅多元共聚柔软剂的合成%Synthesis of multi-copolymer silicone softener

    Institute of Scientific and Technical Information of China (English)

    肖春艳; 贺江平; 崔妍蕾

    2016-01-01

    采用逐步聚合法合成有机硅多元共聚柔软剂,探究投料比、反应时间和温度以及后续溶剂的选择对柔软剂性能的影响,得出最佳的合成工艺。同时与市售柔软剂进行对比,并对整理后的织物进行耐洗性和电镜检测。结果表明,所合成的柔软剂性能优良,具有一定的市场前景。%The synthesis of multi- copolymer silicone softener was carried out by stepwise polymeriza⁃tion. The effects of feed ratio, reaction time and temperature, and solvent on softener performance were stud⁃ied to find out the optimal synthesized process. The comparison with the on- sale softener as wel as the test of washing fastness and SEM results showed the excel ent performance of self- made softener, which had market prospect.

  1. Comparison of heat-transfer coefficient for seawater with softening pretreatment and seawater%脱硬海水与海水传热系数的对比

    Institute of Scientific and Technical Information of China (English)

    杨雁鸣; 马敬环; 刘莹

    2013-01-01

    分别用经过脱硬预处理的海水和传统预处理的海水(以下称海水)进行水平管降膜蒸发实验.研究结果表明,在沸点低于70℃时,随着沸点的升高,两者的传热系数都逐渐增大,但脱硬后海水的传热系数略高于海水;在沸点高于70℃时,脱硬后海水的传热系数远远大于海水.也就是说,脱硬后海水可以在高温时也达到很高的传热系数,从而为脱硬预处理与多效蒸发系统相结合提供实验与设计基础.%In this paper,seawater with simple pretreatment and seawater with softening pretreatment were used to horizontal tube falling film evaporation experiments respectively.Experimentalresults showed that these two heat-transfer coefficients gradually increased with boiling point rising,and the heat-transfer seawater s when the boiling coefficient of seawater with softening pretreatment was slightly higher than seawater'point was below 70 ℃.The heat-transfer coefficient of seawater with softening pretreatment was much higher than the seawater' s when the boiling point was above 70 ℃.In an other word,seawater with softening pretreatment could achieve high heat-transfer coefficient at high temperatures.The experiment provided the experimental and designed base for the combination of softening pretreatment and multiple effect evaporation system.

  2. Generalized adiabatic polaron hopping: Meyer-Neldel compensation and Poole-Frenkel behavior.

    Science.gov (United States)

    Emin, David

    2008-04-25

    The commonly employed adiabatic treatment of polaron hopping is extended to treat the continuous alteration of a carrier wave function with the atoms' movements and a carrier's long-range interaction with a polar surrounding. These features, respectively, introduce carrier-induced softening of the atoms' vibrations and a hopping activation energy that depends on hopping distance. The Meyer-Neldel compensation effect results from carrier-induced softening of vibrations. Poole-Frenkel behavior emerges for electric-field driven polaron hopping in ionic and polar media.

  3. Pressure induced stiffening, thermal softening of bulk modulus and brittle nature of mercury chalcogenides

    Science.gov (United States)

    Varshney, Dinesh; Shriya, Swarna; Sapkale, Raju; Varshney, Meenu; Ameri, M.

    2015-07-01

    The pressure and temperature dependent elastic properties of mercury chalcogenides (HgX; X = S, Se and Te) with pressure induced structural transition from ZnS-type (B3) to NaCl-type (B1) structure have been analyzed within the framework of a model interionic interaction potential with long-range Coulomb and charge transfer interactions, short-range overlap repulsion and van der Waals (vdW) interactions as well as zero point energy effects. Emphasis is on the evaluation of the Bulk modulus with pressure and temperature dependency to yield the Poisson's ratio ν, the Pugh ratio ϕ, anisotropy parameter, Shear and Young's modulus, Lamé's constant, Klein man parameter, elastic wave velocity and Debye temperature. The Poisson's ratio behavior infers that HgX are brittle in nature. To our knowledge this is the first quantitative theoretical prediction of the pressure dependence of elastic and thermodynamical properties explicitly the ductile (brittle) nature of HgX and still awaits experimental confirmations.

  4. Softening Substrates Promote Chondrocytes Phenotype via RhoA/ROCK Pathway.

    Science.gov (United States)

    Zhang, Tao; Gong, Tao; Xie, Jing; Lin, Shiyu; Liu, Yao; Zhou, Tengfei; Lin, Yunfeng

    2016-09-01

    Due to its evascular, aneural, and alymphatic conditions, articular cartilage shows extremely poor regenerative ability. Thus, directing chondrocyte toward a desired location and function by utilizing the mechanical cues of biomaterials is a promising approach for effective tissue regeneration. However, chondrocytes cultured on Petri dish will lose their typical phenotype which may lead to compromised results. Therefore, we fabricated polydimethylsiloxane (PDMS) materials with various stiffness as culture substrates. Cell morphology and focal adhesion of chondrocytes displayed significant changes. The cytoskeletal tension of the adherent cells observed by average myosin IIA fluorescent intensity increased as stiffness of the underlying substrates decreased, consistent with the alteration of chondrocyte phenotype in our study. Immunofluorescent images and q-PCR results revealed that chondrocyte cultured on soft substrates showed better chondrocyte functionalization by more type II collagen and aggrecan expression, related to the lowest mRNA level of Rac-1, RhoA, ROCK-1, and ROCK-2. Taken together, this work not only points out that matrix elasticity can regulate chondrocyte functionalization via RhoA/ROCK pathway, but also provides new prospect for biomechanical control of cell behavior in cell-based cartilage regeneration.

  5. Surface softening in metal-ceramic sliding contacts: an experimental and numerical investigation.

    Science.gov (United States)

    Stoyanov, Pantcho; Merz, Rolf; Romero, Pedro A; Wählisch, Felix C; Abad, Oscar Torrents; Gralla, Robert; Stemmer, Priska; Kopnarski, Michael; Moseler, Michael; Bennewitz, Roland; Dienwiebel, Martin

    2015-02-24

    This study investigates the tribolayer properties at the interface of ceramic/metal (i.e., WC/W) sliding contacts using various experimental approaches and classical atomistic simulations. Experimentally, nanoindentation and micropillar compression tests, as well as adhesion mapping by means of atomic force microscopy, are used to evaluate the strength of tungsten-carbon tribolayers. To capture the influence of environmental conditions, a detailed chemical and structural analysis is performed on the worn surfaces by means of XPS mapping and depth profiling along with transmission electron microscopy of the debris particles. Experimentally, the results indicate a decrease in hardness and modulus of the worn surface compared to the unworn one. Atomistic simulations of nanoindentation on deformed and undeformed specimens are used to probe the strength of the WC tribolayer and despite the fact that the simulations do not include oxygen, the simulations correlate well with the experiments on deformed and undeformed surfaces, where the difference in behavior is attributed to the bonding and structural differences of amorphous and crystalline W-C. Adhesion mapping indicates a decrease in surface adhesion, which based on chemical analysis is attributed to surface passivation.

  6. Softened and flexible biodegradable poly(lactic acid) and its electromechanical properties for actuator application.

    Science.gov (United States)

    Thummarungsan, Natlita; Pattavarakorn, Datchanee; Sirivat, Anuvat

    2016-12-01

    Poly (lactic acid) (PLA) is a biodegradable polymer with high stiffness presenting a limitation for using in actuator applications. Adding a plasticizer is one way to solve this problem to enhance flexibility and improve electromechanical properties of pristine PLA. In this work, the PLA films were prepared via a simple solvent casting method. The influences of plasticizer type and electric field strength on electromechanical behavior of PLA films were investigated by the melt rheometer and bending measurement. For the PLA films filled with dibutyl phthalate (DBP), the storage modulus, G', immediately increased towards its steady state and rapidly recovered to its original value with and without electric field, respectively, which can be referred to a reversible system. On the other hand, the PLA film with Tween 20 processed the highest ∆G׳/G׳0 of 1.34 due to the available amount of polarized groups. In the bending measurement, the dielectrophoresis forces of plasticized PLA films were found to increase with increasing electric field where the deflections occurred towards anode side as the polarized groups generated negative charges. The DBP_PLA1.5D film exhibited the greatest bending and dielectrophoresis force. Thus, the biodegradable PLA along with DBP combine to have a great potential towards actuator application. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Relationship between crystallographic structure of the Ti{sub 2}O{sub 3}/MnS complex inclusion and microstructure in the heat-affected zone (HAZ) in steel processed by oxide metallurgy route and impact toughness

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Zhihui; Liu, Shilong [School of Materials Science and Engineering, University of Science and Technology Beijing (China); Wang, Xuemin, E-mail: wxm@mater.ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing (China); Shang, Chengjia [School of Materials Science and Engineering, University of Science and Technology Beijing (China); Misra, R.D.K. [Laboratory for Excellence in Advanced Steel Research, Center for Structural and Functional Materials Research and Innovation, Department of Metallurgical and Materials Engineering, University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States)

    2015-08-15

    A new method based on electron back scattered diffraction (EBSD) is proposed to determine the structure of titanium oxide/MnS complex inclusion which induced the formation of intragranular acicular ferrite (IAF) in heat-affected zone (HAZ) in steel processed by oxide metallurgy route. It was found that the complex inclusion was Ti{sub 2}O{sub 3}/MnS, the orientation relationship between Ti{sub 2}O{sub 3} and MnS was also examined, and the crystallographic orientation relationship among IAF, Ti{sub 2}O{sub 3}/MnS complex inclusion, austenite, bainite formed at lower temperature is researched systematically. It was observed that MnS precipitated on Ti{sub 2}O{sub 3} at specific habit plane and direction and MnS had a specific orientation relationship ((0001) Ti{sub 2}O{sub 3}//(111) MnS), <10–10> Ti{sub 2}O{sub 3}//<110> MnS) with respect to Ti{sub 2}O{sub 3}. Intragranular acicular ferrite (IAF) nucleated on MnS part of the Ti{sub 2}O{sub 3}/MnS complex inclusion had no specific orientation relationship with MnS. IAF and the surrounding bainite had different Bain groups, so that there was an increase in high angle boundaries, which was beneficial for the toughness of HAZ. - Highlights: • The inclusion of TiO{sub x}/MnS that induced IAF formation is identified to be Ti{sub 2}O{sub 3}/MnS. • The inclusion is identified based on electron back scattered diffraction (EBSD). • MnS and Ti{sub 2}O{sub 3} had specific orientation relationship of Ti{sub 2}O{sub 3}/MnS complex inclusion. • The IAFs formed on the same inclusion tend to be in one Bain group. • IAF and the surrounding bainite tend to be in different Bain groups.

  8. Development of a design methodology for high-temperature cyclic application of materials which experience cyclic softening

    Energy Technology Data Exchange (ETDEWEB)

    Leckie, F.A.; Marriott, D.L.; Stubbins, J.F.; Handrock, J.L.; Kschinka, B.

    1987-08-01

    The project described in this report has, as its beginning, two investigations, the first a study of the effect of material softening on the overall structural stability of complex components, and the second an evaluation of damage induced through cyclic loads combined with high temperature environmental effects. The initial work was carried out on one grade of 2.25Cr 1Mo steel, with the intention of extending the investigation to other grades once the investigative techniques had been settled. However, considerable interest has grown in the application of modified forms of austenitic steel to very high temperature use in superheaters and reheaters. The ability to utilize these materials can mean an increase of 100{degree}C in the top temperature in a power plant, which converts into a significant improvement in thermal efficiency for a very small investment in material. Therefore, the direction of this project has been modified to continue on this class rather than the ferritic alloys originally under consideration. The basic problem to be investigated in the austenitics is the concern for possible strength variations, either positive or negative, induced in the very complex microstructures by service conditions of cyclic load and high temperature. 23 refs., 31 figs., 6 tabs.

  9. Instability criterion for the system composed of elastic beam and strain-softening pillar based on gradient-dependent plasticity

    Institute of Scientific and Technical Information of China (English)

    Xuebin Wang

    2005-01-01

    A mechanical model is proposed for the system of elastic beam and strain-softening pillar where strain localization is initiated at peak shear stress. To obtain the plastic deformation of the pillar due to the shear slips of multiple shear bands, the pillar is divided into several narrow slices where compressive deformation is treated as uniformity. In the light of the compatibility condition of deformation, the total compressive displacement of the pillar is equal to the displacement of the beam in the middle span. An insta bility criterion is derived analytically based on the energy principle using a known size of localization band according to gradientdependent plasticity. The main advantage of the present model is that the effects of the constitutive parameters of rock and the geometrical size of structure are reflected in the criterion. The condition that the derivative of distributed load with respect to the deflection of the beam in the middle span is less than zero is not only equivalent to, but also even more concise in form than the instability criterion. To study the influences of constitutive parameters and geometrical size on stability, some examples are presented.

  10. Anomalous compression behavior of germanium during phase transformation

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Xiaozhi [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203 (China); Tan, Dayong [Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203 (China); Guangzhou Institute of Geochemistry, Chinese Academic of Sciences, Guangzhou 510640 (China); Ren, Xiangting [Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203 (China); Yang, Wenge, E-mail: yangwg@hpstar.ac.cn, E-mail: duanweihe@scu.edu.cn [Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203 (China); High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory, Carnegie Institution of Washington, Argonne, Illinois 60439 (United States); He, Duanwei, E-mail: yangwg@hpstar.ac.cn, E-mail: duanweihe@scu.edu.cn [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Institute of Fluid Physics and National Key Laboratory of Shockwave and Detonation Physic, China Academy of Engineering Physics, Mianyang 621900 (China); Mao, Ho-Kwang [Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203 (China); High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory, Carnegie Institution of Washington, Argonne, Illinois 60439 (United States); Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015 (United States)

    2015-04-27

    In this article, we present the abnormal compression and plastic behavior of germanium during the pressure-induced cubic diamond to β-tin structure transition. Between 8.6 GPa and 13.8 GPa, in which pressure range both phases are co-existing, first softening and followed by hardening for both phases were observed via synchrotron x-ray diffraction and Raman spectroscopy. These unusual behaviors can be interpreted as the volume misfit between different phases. Following Eshelby, the strain energy density reaches the maximum in the middle of the transition zone, where the switch happens from softening to hardening. Insight into these mechanical properties during phase transformation is relevant for the understanding of plasticity and compressibility of crystal materials when different phases coexist during a phase transition.

  11. Unconventional emergence of elastic softening induced by magnetic fields in the unusual heavy-fermion compound PrFe{sub 4}P{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, Y [Department of Materials Science and Engineering, Iwate University, Morioka 020-8551 (Japan); Yoshizawa, M [Department of Materials Science and Engineering, Iwate University, Morioka 020-8551 (Japan); Yamaguchi, T [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Hazama, H [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Nemoto, Y [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Goto, T [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Matsuda, T D [Department of Physics, Tokyo Metropolitan University, Hachioji 192-0397 (Japan); Sugawara, H [Department of Physics, Tokyo Metropolitan University, Hachioji 192-0397 (Japan); Sato, H [Department of Physics, Tokyo Metropolitan University, Hachioji 192-0397 (Japan)

    2002-11-18

    Ultrasonic measurement on the filled skutterudite compound PrFe{sub 4}P{sub 12} exhibits a mysterious temperature dependence of the elastic constant (C{sub 11} - C{sub 12})/2. Pronounced elastic softening at low temperatures is revived by applying a magnetic field. This fact strongly suggests the 4f-multiplet ground state of the Pr ion split by the crystalline electric field (CEF) to be a {gamma}{sub 3} non-Kramers doublet. The expectation value of a quadrupole moment with {gamma}{sub 3} symmetry in the CEF ground state, which leads to elastic softening at low temperature, was evaluated by theoretical fitting to the present results. This may imply that suppression of the electric quadrupole Kondo effect occurs in PrFe{sub 4}P{sub 12} and the quadrupole moment becomes steady due to the application of a magnetic field. (letter to the editor)

  12. Unconventional emergence of elastic softening induced by magnetic fields in the unusual heavy-fermion compound PrFe sub 4 P sub 1 sub 2

    CERN Document Server

    Nakanishi, Y; Yamaguchi, T; Hazama, H; Nemoto, Y; Goto, T; Matsuda, T D; Sugawara, H; Sato, H

    2002-01-01

    Ultrasonic measurement on the filled skutterudite compound PrFe sub 4 P sub 1 sub 2 exhibits a mysterious temperature dependence of the elastic constant (C sub 1 sub 1 - C sub 1 sub 2)/2. Pronounced elastic softening at low temperatures is revived by applying a magnetic field. This fact strongly suggests the 4f-multiplet ground state of the Pr ion split by the crystalline electric field (CEF) to be a GAMMA sub 3 non-Kramers doublet. The expectation value of a quadrupole moment with GAMMA sub 3 symmetry in the CEF ground state, which leads to elastic softening at low temperature, was evaluated by theoretical fitting to the present results. This may imply that suppression of the electric quadrupole Kondo effect occurs in PrFe sub 4 P sub 1 sub 2 and the quadrupole moment becomes steady due to the application of a magnetic field. (letter to the editor)

  13. Mössbauer spectroscopy research on magnetic softening of Fe84B10C6 amorphous alloy during low-temperature annealing

    Science.gov (United States)

    Cao, C. C.; Wang, Y. G.; Xia, G. T.; Zhu, L.; Meng, Y.; Zhai, X. B.

    2017-06-01

    The mechanism of magnetic softening in Fe84B10C6 amorphous alloys annealed at a temperature below the crystallization temperature has been investigated by Mössbauer spectroscopy. With the prolongation of annealing time, saturation flux density (B\\text{S}) increases gradually but coercivity (H\\text{C}) firstly declines to a minimum and then increases drastically. All the modulations of local structure strengthen the magnetic exchange between Fe neighbor atoms during low-temperature annealing. The structural relaxation at the early stage of annealing including annihilation of excess free volume and residual stress rotates the easy axis to the ribbon plane and weakens magnetic anisotropy, while the subsequent structural relaxation contributing to chemical inhomogeneity results in the inverse situation. Thus, appropriate annealing can magnetically soften amorphous alloys. For the Fe84B10C6 amorphous alloy, soft magnetic properties are optimized when annealed at 493 K for 100 s.

  14. Elastic softening mode change in Y{sub 1-x}Ca{sub x}TiO{sub 3} by Ca-doping

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Takashi [Department of Quantum Matter, ADSM, Hiroshima University, Higashi-Hiroshima 739-8530 (Japan)]. E-mail: tsuzuki@hiroshima-u.ac.jp; Morita, Shinya [Department of Quantum Matter, ADSM, Hiroshima University, Higashi-Hiroshima 739-8530 (Japan); Higaki, Haruhiro [Department of Quantum Matter, ADSM, Hiroshima University, Higashi-Hiroshima 739-8530 (Japan); Ishii, Isao [Department of Quantum Matter, ADSM, Hiroshima University, Higashi-Hiroshima 739-8530 (Japan); Takemura, Masaki [Department of Quantum Matter, ADSM, Hiroshima University, Higashi-Hiroshima 739-8530 (Japan); Iga, Fumitoshi [Department of Quantum Matter, ADSM, Hiroshima University, Higashi-Hiroshima 739-8530 (Japan); Takabatake, Toshiro [Department of Quantum Matter, ADSM, Hiroshima University, Higashi-Hiroshima 739-8530 (Japan); Tsubota, Masami [JAERI/SPring-8, Hyogo 679-5198 (Japan)

    2006-05-01

    We measured various elastic moduli of single-crystalline Y{sub 1-x}Ca{sub x}TiO{sub 3} (x=0, and 0.2) as a function of temperature by means of an ultrasonic technique. Remarkable elastic softening has been found in transverse C{sub 44} for the sample with x=0 around 60K, indicating structural symmetry lowering corresponding to the e{sub yz} strain. In contrast, the sample with x=0.2 shows large softening in C{sub 55} in response to e{sub zx} around 130K. These results reveal that Y{sub 1-x}Ca{sub x}TiO{sub 3} (x=0, and 0.2) undergo a structural transition and the crystal symmetry of the low temperature phase is changed by Ca-doping.

  15. Stressed Heat Affected Zone Simulations of AerMet 100 Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Puskar, Joseph D.; Smith, Mark F.

    1999-08-03

    AerMet 100 is a high strength, high fracture toughness alloy designed for use in aerospace applications. In previous work the welding behavior of this alloy has been evaluated, and it has been shown that a softened region in the heat-affected zone (HAZ) is a principal feature of the weld zone. A model for this softening, based on classical theories of precipitate coarsening and isothermal softening data, was developed and found to provide a reasonable description for weld thermal cycle simulation (Gleeble) experiments. Recent work has shown, however, that softening in real welds is not always well predicted by this model, so that additional effects, which are not captured in conventional Gleeble thermal cycle simulations must be addressed. In particular, the stresses associated with real weld HAZ's may modify the softening kinetics. In the current work, Gleeble simulations in both stress-free and stressed conditions have been conducted and the kinetics compared. The accuracy of the thermal model predictions have also been considered regarding their impact on estimated hardness values.

  16. Suppression of the structural phase transition and lattice softening in slightly underdoped Ba1-xKxFe2As2 with electronic phase separation

    DEFF Research Database (Denmark)

    Inosov, D.S.; Leineweber, A.; Yang, X.P.;

    2009-01-01

    We present x-ray powder diffraction (XRPD) and neutron-diffraction measurements on the slightly underdoped iron-pnictide superconductor Ba1−xKxFe2As2, Tc=32 K. Below the magnetic-transition temperature Tm=70 K, both techniques show an additional broadening of the nuclear Bragg peaks, suggesting a...... the lattice softening, showing that it can account for a major part of the observed increase in the microstrain....

  17. Influence of non-metallic inclusions on the strength properties of screws made of 35B2+Cr steel after softening

    OpenAIRE

    Krawczyk, J.; Pawłowski, B

    2012-01-01

    Purpose: This paper presents the results of the research on the influence of non-metallic inclusions on strength properties of 35B2+Cr steel screws.Design/methodology/approach: The investigations were carried out on screws after softening. The investigated steels with different fraction of non-metallic inclusions were delivered by three different suppliers.Findings: It was proved, that in spite of the level of fraction of non-metallic inclusions compatible with the corresponding standards, th...

  18. Application of the specular and diffuse reflection analysis for in vitro diagnostics of dental erosion: correlation with enamel softening, roughness, and calcium release

    Science.gov (United States)

    Rakhmatullina, Ekaterina; Bossen, Anke; Höschele, Christoph; Wang, Xiaojie; Beyeler, Barbara; Meier, Christoph; Lussi, Adrian

    2011-10-01

    We present assembly and application of an optical reflectometer for the analysis of dental erosion. The erosive procedure involved acid-induced softening and initial substance loss phases, which are considered to be difficult for visual diagnosis in a clinic. Change of the specular reflection signal showed the highest sensitivity for the detection of the early softening phase of erosion among tested methods. The exponential decrease of the specular reflection intensity with erosive duration was compared to the increase of enamel roughness. Surface roughness was measured by optical analysis, and the observed tendency was correlated with scanning electron microscopy images of eroded enamel. A high correlation between specular reflection intensity and measurement of enamel softening (r2 >= -0.86) as well as calcium release (r2 >= -0.86) was found during erosion progression. Measurement of diffuse reflection revealed higher tooth-to-tooth deviation in contrast to the analysis of specular reflection intensity and lower correlation with other applied methods (r2 = 0.42-0.48). The proposed optical method allows simple and fast surface analysis and could be used for further optimization and construction of the first noncontact and cost-effective diagnostic tool for early erosion assessment in vivo.

  19. Firmness at Harvest Impacts Postharvest Fruit Softening and Internal Browning Development in Mechanically Damaged and Non-damaged Highbush Blueberries (Vaccinium corymbosum L.).

    Science.gov (United States)

    Moggia, Claudia; Graell, Jordi; Lara, Isabel; González, Guillermina; Lobos, Gustavo A

    2017-01-01

    Fresh blueberries are very susceptible to mechanical damage, which limits postharvest life and firmness. Softening and susceptibility of cultivars "Duke" and "Brigitta" to developing internal browning (IB) after mechanical impact and subsequent storage was evaluated during a 2-year study (2011/2012, 2012/2013). On each season fruit were carefully hand-picked, segregated into soft (cultivar or season, high variability in fruit firmness was observed within each commercial harvest, and significant differences in IB and softening rates were found. "Duke" exhibited high softening rates, as well as high and significant r(2) between firmness and IB, but little differences for dropped vs. non-dropped fruit. "Brigitta," having lesser firmness rates, exhibited almost no relationships between firmness and IB (especially for non-dropped fruit), but marked differences between dropping treatments. Firmness loss and IB development were related to firmness at harvest, soft and firm fruit being the most and least damaged, respectively. Soft fruit were characterized by greater IB development during storage along with high soluble solids/acid ratio, which could be used together with firmness to estimate harvest date and storage potential of fruit. Results of this work suggest that the differences in fruit quality traits at harvest could be related to the time that fruit stay on the plant after turning blue, soft fruit being more advanced in maturity. Finally, the observed differences between segregated categories reinforce the importance of analyzing fruit condition for each sorted group separately.

  20. Ethylene regulates Apple (Malus x domestica) fruit softening through a dose x time-dependent mechanism and through differential sensitivities and dependencies of cell wall-modifying genes.

    Science.gov (United States)

    Ireland, Hilary S; Gunaseelan, Kularajathevan; Muddumage, Ratnasiri; Tacken, Emma J; Putterill, Jo; Johnston, Jason W; Schaffer, Robert J

    2014-05-01

    In fleshy fruit species that have a strong requirement for ethylene to ripen, ethylene is synthesized autocatalytically, producing increasing concentrations as the fruits ripen. Apple fruit with the ACC OXIDASE 1 (ACO1) gene suppressed cannot produce ethylene autocatalytically at ripening. Using these apple lines, an ethylene sensitivity dependency model was previously proposed, with traits such as softening showing a high dependency for ethylene as well as low sensitivity. In this study, it is shown that the molecular control of fruit softening is a complex process, with different cell wall-related genes being independently regulated and exhibiting differential sensitivities to and dependencies on ethylene at the transcriptional level. This regulation is controlled through a dose × time mechanism, which results in a temporal transcriptional response that would allow for progressive cell wall disassembly and thus softening. This research builds on the sensitivity dependency model and shows that ethylene-dependent traits can progress over time to the same degree with lower levels of ethylene. This suggests that a developmental clock measuring cumulative ethylene controls the fruit ripening process.

  1. Physical properties of root crops treated with novel softening technology capable of retaining the shape, color, and nutritional value of foods.

    Science.gov (United States)

    Umene, Shingo; Hayashi, Masahiro; Kato, Kumiko; Masunaga, Hiroaki

    2015-04-01

    Hard, difficult-to-eat root crops (carrots and burdock roots) were homogeneously softened by an enzyme permeation method so that they could be mashed easily by the tongue while retaining appearance, flavor, and nutrients. The appearance, color, and nutritional value of these foods were equivalent to those of normally cooked root crops of the same type. The firmness of the softened root crops was at least 100 times as low as normally cooked root crops and lower than some care food products for patients with swallowing disorders. Compared with control root crops, which were treated with a freeze-thaw infusion method, the treated foods were 10 to 25 times as soft, with significantly lower rates of foodstuff syneresis and better preservation of color and nutritional value. Furthermore, the cell walls of the treated burdock roots resembled those of normally cooked ones, while the cells of freeze-thaw infusion burdock roots were destroyed and few cell walls remained. It was expected that these root crops softened by the enzymatic processing could be one of the best model foods for patients with masticatory disturbance or swallowing disorders or both.

  2. Application of the specular and diffuse reflection analysis for in vitro diagnostics of dental erosion: correlation with enamel softening, roughness, and calcium release

    Science.gov (United States)

    Rakhmatullina, Ekaterina; Bossen, Anke; Höschele, Christoph; Wang, Xiaojie; Beyeler, Barbara; Meier, Christoph; Lussi, Adrian

    2011-01-01

    We present assembly and application of an optical reflectometer for the analysis of dental erosion. The erosive procedure involved acid-induced softening and initial substance loss phases, which are considered to be difficult for visual diagnosis in a clinic. Change of the specular reflection signal showed the highest sensitivity for the detection of the early softening phase of erosion among tested methods. The exponential decrease of the specular reflection intensity with erosive duration was compared to the increase of enamel roughness. Surface roughness was measured by optical analysis, and the observed tendency was correlated with scanning electron microscopy images of eroded enamel. A high correlation between specular reflection intensity and measurement of enamel softening (r2 ≥ −0.86) as well as calcium release (r2 ≥ −0.86) was found during erosion progression. Measurement of diffuse reflection revealed higher tooth-to-tooth deviation in contrast to the analysis of specular reflection intensity and lower correlation with other applied methods (r2 = 0.42–0.48). The proposed optical method allows simple and fast surface analysis and could be used for further optimization and construction of the first noncontact and cost-effective diagnostic tool for early erosion assessment in vivo. PMID:22029364

  3. Application of the specular and diffuse reflection analysis for in vitro diagnostics of dental erosion: correlation with enamel softening, roughness, and calcium release.

    Science.gov (United States)

    Rakhmatullina, Ekaterina; Bossen, Anke; Höschele, Christoph; Wang, Xiaojie; Beyeler, Barbara; Meier, Christoph; Lussi, Adrian

    2011-10-01

    We present assembly and application of an optical reflectometer for the analysis of dental erosion. The erosive procedure involved acid-induced softening and initial substance loss phases, which are considered to be difficult for visual diagnosis in a clinic. Change of the specular reflection signal showed the highest sensitivity for the detection of the early softening phase of erosion among tested methods. The exponential decrease of the specular reflection intensity with erosive duration was compared to the increase of enamel roughness. Surface roughness was measured by optical analysis, and the observed tendency was correlated with scanning electron microscopy images of eroded enamel. A high correlation between specular reflection intensity and measurement of enamel softening (r(2) ≥ -0.86) as well as calcium release (r(2) ≥ -0.86) was found during erosion progression. Measurement of diffuse reflection revealed higher tooth-to-tooth deviation in contrast to the analysis of specular reflection intensity and lower correlation with other applied methods (r(2) = 0.42-0.48). The proposed optical method allows simple and fast surface analysis and could be used for further optimization and construction of the first noncontact and cost-effective diagnostic tool for early erosion assessment in vivo.

  4. Determination of alkyltrimethylammonium surfactants in hair conditioners and fabric softeners by gas chromatography-mass spectrometry with electron-impact and chemical ionization.

    Science.gov (United States)

    Tsai, Pei-Chuan; Ding, Wang-Hsien

    2004-02-20

    The commercial hair conditioners and fabric softeners were analyzed for the content of alkyltrimethylammonium compounds (ATMACs) by gas chromatography-mass spectrometry (GC-MS) with electron impact (EI) and low-pressure positive-ion chemical ionization (PICI) modes. The method involves mixed diluted samples (adjust pH to 10.0) with potassium iodide to enhance the extraction of iodide-ATMA+ ion pairs by direct liquid-liquid extraction. The iodide-ATMA+ pairs were then demethylated to their corresponding nonionic alkyldimethylamines (ADMAs) by thermal decomposition in a GC injection-port. A high abundance of ADMAs was detected at the temperature above 300 degrees C in the GC injection-port. The enhanced selectivity of quasi-molecular ion chromatograms of C12-C18-ADMA, obtained using methanol PICI-MS enables ADMAs to be identified. The accuracy and precision of the method was validated and was successfully applied to determine contents of ATMAC in commercial hair conditioners and fabric softeners. The contents of total measured ATMAC ranged from 0.4 to 6.9% for hair conditioners, and from 3.3 to 4.6% for fabric softeners.

  5. Defect Recovery in Severely Deformed Ferrite Lamellae During Annealing and Its Impact on the Softening of Cold-Drawn Pearlitic Steel Wires

    Science.gov (United States)

    Chen, Y. Z.; Csiszár, G.; Cizek, J.; Shi, X. H.; Borchers, C.; Li, Y. J.; Liu, F.; Kirchheim, R.

    2016-02-01

    Cold-drawn pearlitic steel wires with a drawing true strain of 3 were annealed at temperatures ( T ann) ranging from 423 K to 723 K (150 °C to 450 °C) with an interval of 50 K. Recovery of the lattice defects in the severely deformed ferrite lamellae were characterized by means of high-energy X-ray diffraction and positron annihilation techniques (including positron annihilation spectroscopy and coincidence Doppler broadening spectroscopy). Accordingly, the impact of defect recovery on the softening of the annealed wires was investigated. It is found that at low temperatures [ T ann ≤ 523 K (250 °C)], the recovery of the lattice defects in ferrite lamellae is dominated by the agglomeration and annihilation of vacancy clusters, while at T ann > 523 K (250 °C), the recovery process is controlled by the annihilation of dislocations. Further analyses on the softening of the annealed wires indicate that the evolutions of dislocation density and concentration of vacancy clusters, and the strain age hardening in ferrite lamellae play important roles in changing the strength of the wires. The strain aging hardening leads to a maximum strength at 473 K (150 °C). Above 523 K (250 °C), the annihilations of vacancy clusters and dislocations in ferrite lamellae cause a continuous softening of the wires, where the decrease in dislocation density plays a major role.

  6. Specific Changes of Exocarp and Mesocarp Occurring during Softening Differently Affect Firmness in Melting (MF) and Non Melting Flesh (NMF) Fruits.

    Science.gov (United States)

    Onelli, E; Ghiani, A; Gentili, R; Serra, S; Musacchi, S; Citterio, S

    2015-01-01

    Melting (MF) and non melting flesh (NMF) peaches differ in their final texture and firmness. Their specific characteristics are achieved by softening process and directly dictate fruit shelf life and quality. Softening is influenced by various mechanisms including cell wall reorganization and water loss. In this work, the biomechanical properties of MF Spring Crest's and NMF Oro A's exocarp and mesocarp along with the amount and localization of hydroxycinnamic acids and flavonoids were investigated during fruit ripening and post-harvest. The objective was to better understand the role played by water loss and cell wall reorganization in peach softening. Results showed that in ripe Spring Crest, where both cell turgor loss and cell wall dismantling occurred, mesocarp had a little role in the fruit reaction to compression and probe penetration response was almost exclusively ascribed to the epidermis which functioned as a mechanical support to the pulp. In ripe Oro A's fruit, where cell wall disassembly did not occur and the loss of cell turgor was observed only in mesocarp, the contribution of exocarp to fruit firmness was consistent but relatively lower than that of mesocarp, suggesting that in addition to cell turgor, the integrity of cell wall played a key role in maintaining NMF fruit firmness. The analysis of phenols suggested that permeability and firmness of epidermis were associated with the presence of flavonoids and hydroxycinnamic acids.

  7. Specific Changes of Exocarp and Mesocarp Occurring during Softening Differently Affect Firmness in Melting (MF and Non Melting Flesh (NMF Fruits.

    Directory of Open Access Journals (Sweden)

    E Onelli

    Full Text Available Melting (MF and non melting flesh (NMF peaches differ in their final texture and firmness. Their specific characteristics are achieved by softening process and directly dictate fruit shelf life and quality. Softening is influenced by various mechanisms including cell wall reorganization and water loss. In this work, the biomechanical properties of MF Spring Crest's and NMF Oro A's exocarp and mesocarp along with the amount and localization of hydroxycinnamic acids and flavonoids were investigated during fruit ripening and post-harvest. The objective was to better understand the role played by water loss and cell wall reorganization in peach softening. Results showed that in ripe Spring Crest, where both cell turgor loss and cell wall dismantling occurred, mesocarp had a little role in the fruit reaction to compression and probe penetration response was almost exclusively ascribed to the epidermis which functioned as a mechanical support to the pulp. In ripe Oro A's fruit, where cell wall disassembly did not occur and the loss of cell turgor was observed only in mesocarp, the contribution of exocarp to fruit firmness was consistent but relatively lower than that of mesocarp, suggesting that in addition to cell turgor, the integrity of cell wall played a key role in maintaining NMF fruit firmness. The analysis of phenols suggested that permeability and firmness of epidermis were associated with the presence of flavonoids and hydroxycinnamic acids.

  8. Cloning and Expression Analysis of an XET cDNA in the Peel and Pulp of Banana Fruit Ripening and Softening

    Institute of Scientific and Technical Information of China (English)

    LUWang-Jin; RyoheiNAKANO; YasutakaKUBO; AkitsuguINABAt; JIANGYue-Ming

    2004-01-01

    Xyloglucan endotransglycosylase (XET) is thought to be involved in fruit softening throughdisassembly of xyloglucan, which is the predominant hemicellulose of cell wall. To study the relationshipbetween fruit softening and XET during banana (Musa acuminata Colla cv. Grand Nain) fruit ripening, a fulllength cDNA (1 095 bp) encoding an XET, MA-XET1, was isolated from ripening banana fruit using RT-PCRand RACE-PCR (rapid amplification of cDNA ends) methods. Sequence analysis showed that the cDNAcontains 5' untranslated region of 66 bp, 3' untranslated region of 189 bp and ORF of 840 bp, encoding apredicted polypeptide of 280 amino acids, including DE|DFEFL motif, which is a presumptive catalyticdomain conserved in XETs. DNA gel blot analysis demonstrated that MA-XET1 is encoded by a multi-copyfamily in the banana genome. RNA gel blot analysis revealed that the level of MA-XET1 transcript in thepulp was undetectable, increased and decreased slightly at the preclimacteric, climacteric and postclimactericstages, respectively. In the peel, accumulation of MA-XET1 transcript was low, increased dramatically andthen decreased rapidly, at preclimacteric, climacteric and postclimacteric stages, respectively. Treatmentof fruit with propylene, an analog of ethylene, decreased the firmness and enhanced the accumulation ofMA-XET1 transcript in the peel and pulp. These results suggest that MA-XET1 is involved in softening ofthe peel and pulp during banana fruit ripening and its expression is regulated by ethylene at transcriptionallevel.

  9. Segregation behavior of phosphorus in the heat-affected zone of an A533B/A182 dissimilar weld joint before and after simulated thermal aging

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Ziqing, E-mail: ziqing.zhai@rbm.qse.tohoku.ac.jp [Graduate School of Engineering, Tohoku University, 6-6-01-2 Aoba, Aramaki, Aoba-Ku, Sendai 980-8579 (Japan); Miyahara, Yuichi [Material Science Research Laboratory, Central Research Institute of Electric Power Industry, 2-6-1 Nagasaka, Yokosuka, Kanagawa 240-0196 (Japan); Abe, Hiroshi; Watanabe, Yutaka [Graduate School of Engineering, Tohoku University, 6-6-01-2 Aoba, Aramaki, Aoba-Ku, Sendai 980-8579 (Japan)

    2014-09-15

    Highlights: • Impacts of aging on P segregation in actual heat-affected zone were examined by 3D-APT. • Non-equilibrium segregation of P dominated in subsequent cooling after welding. • Equilibrium segregation of P prevailed in step-cooling heat treatment. • High enrichment of P at grain/packet boundaries occurred in CGHAZ and ICCGHAZ. • Level of P enrichment at precipitate/matrix interface seemed species-dependent. - Abstract: The segregation behavior of phosphorus (P) in the heat-affected zone (HAZ) of an A533B/A182 dissimilar weld joint before and after step cooling was investigated with atom probe tomography. At grain/packet boundaries, the final P segregation level consisted of non-equilibrium segregation that occurred during cooling after welding and post-weld heat treatment (PWHT) and equilibrium segregation that occurred during step cooling. In both processes, higher P coverage was observed in the coarse-grained and intercritically reheated coarse-grained HAZ than in the fine-grained HAZ and base material. The cooling after welding and PWHT seemed to have a pronounced impact on P segregation in the subsequent aging process. In addition, P segregation also occurred at the precipitate/matrix interfaces of cementite, Mo{sub 2}C and Al–Si rich precipitates. The evolution of P coverage at these two types of sites suggested increasing risks of embrittlement with an increase in aging time.

  10. Segregation behavior of phosphorus in the heat-affected zone of an A533B/A182 dissimilar weld joint before and after simulated thermal aging

    Science.gov (United States)

    Zhai, Ziqing; Miyahara, Yuichi; Abe, Hiroshi; Watanabe, Yutaka

    2014-09-01

    The segregation behavior of phosphorus (P) in the heat-affected zone (HAZ) of an A533B/A182 dissimilar weld joint before and after step cooling was investigated with atom probe tomography. At grain/packet boundaries, the final P segregation level consisted of non-equilibrium segregation that occurred during cooling after welding and post-weld heat treatment (PWHT) and equilibrium segregation that occurred during step cooling. In both processes, higher P coverage was observed in the coarse-grained and intercritically reheated coarse-grained HAZ than in the fine-grained HAZ and base material. The cooling after welding and PWHT seemed to have a pronounced impact on P segregation in the subsequent aging process. In addition, P segregation also occurred at the precipitate/matrix interfaces of cementite, Mo2C and Al-Si rich precipitates. The evolution of P coverage at these two types of sites suggested increasing risks of embrittlement with an increase in aging time.

  11. Experimental Investigation of Fatigue Crack Growth Behavior in Friction Stir Welded 7075-T111 Aluminum Alloy Joints under Constant Stress Intensity Factor Range Control Testing (For L T Orientation Specimen)

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Yeui Han; Kim, Seon Jin [Pukyong Nat' l Univ., Busan (Korea, Republic of)

    2013-06-15

    In this study, as a series of studies aimed at investigating the spatial randomness of fatigue crack growth for friction stir welded (FSWed) 7075-T111 aluminum alloy joints, the fatigue crack growth behavior of FSWed 7075-T111 aluminum alloy joints was investigated for L T orientation specimens. Fatigue crack growth tests were conducted under constant stress intensity factor range (SEFOR) control for 5 specimens of the FSWed 7075-T111 aluminum alloy, including base metal (B M), heat affected zone (Haz), and weld metal (W M) specimens. The mean fatigue crack growth rate of W M specimens was found to be the highest, whereas that of Haz and W M specimens was the lowest. Furthermore, the variability of fatigue crack growth rate was found to be the highest in W M specimens and lowest in B M specimens.

  12. Microstructure- and Strain Rate-Dependent Tensile Behavior of Fiber Laser-Welded DP980 Steel Joint

    Science.gov (United States)

    Jia, Qiang; Guo, Wei; Peng, Peng; Li, Minggao; Zhu, Ying; Zou, Guisheng

    2016-02-01

    DP980 steels were butt-welded by fiber laser welding. The microstructures, microhardness distribution, and tensile behavior of the joint were investigated. The results showed that the fusion zone (FZ) consisted of fully martensite with higher hardness compared to the base metal (BM). A softened zone (20 HV0.2 drop) was produced in heat-affected zone due to martensite tempering during the laser welding. The ultimate tensile strength (UTS) and yield strength (YS) of the laser-welded joint were not degraded compared to BM with the existence of softened zone. The UTS and YS of the welded joint increased with the increase of tensile strain rate. The work hardening exponents of the BM and welded joint showed weak positive strain rate dependence. The deformation of softened zone was restrained by the hardened FZ during loading, resulting in a higher work hardening rate of softened zone than that of BM. The failure of welded joint occurred in the BM instead of softened zone. The fracture surfaces of the joint exhibited typical ductile fracture over strain rate from 0.0001 to 0.1 s-1.

  13. Softening and hardening by. gamma. yields. epsilon. martensitic transformation during deformation in high Mn steels. Ko Mn tetsu gokin ni okeru. gamma. yields. epsilon. martensite hentai ni yoru nanka to koka

    Energy Technology Data Exchange (ETDEWEB)

    Tomota, Y.; Ryufuku, S.; Piao, M. (Ibaraki University, Ibaraki (Japan). Faculty of Engineering)

    1991-01-15

    In high Mn steel, martensitic transformation of gamma to epsilon occurs under the ordinary pressure. Its application comprises utilization of its configuration memory properties and high work hardening characteristics. The present report studied, by using Fe-Mn type alloy, added with Si or Co, the influence of martensitic transformation of gamma to epsilon on the deformation behavior. Tensile test, 2mm/min in speed, being made on molten/cast alloy ingot, thermally treated as specified, epsilon was quantitatively analyzed by X-ray diffraction. The above test/analysis pointed out many notes in result and knowledge, as follows among others: The addition with Si or Co, lowering the Neel temperature, quantitatively increases the epsilon martensite, produced by the processing. The produced quantity of epsilon martensite in case of addition with Si is small, as compared with that in case of two-element Fe-Mn type alloy without addition and in case of addition with Co. All the tested alloys give the softening phenomenon by the martensitic transformation of gamma to epsilon. The pre-existing epsilon plate is a strong barrier for the further plastic flow, which accordingly accelerates the work hardening. 20 refs., 10 figs., 1 tab.

  14. Scientific Opinion on the substantiation of a health claim related to beta-palmitate and contribution to softening of stools pursuant to Article 14 of Regulation (EC No 1924/2006

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA

    2014-02-01

    Full Text Available Following an application from Specialised Nutrition Europe (formerly IDACE, submitted for authorisation of a health claim pursuant to Article 14 of Regulation (EC No 1924/2006 via the Competent Authority of France, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA was asked to deliver an opinion on the scientific substantiation of a health claim related to beta-palmitate and contribution to softening of stools. The food constituent, beta-palmitate, that is the subject of the health claim, is sufficiently characterised. Contribution to softening of stools is a beneficial physiological effect for infants. In weighing the evidence the Panel took into account that, out of two human intervention studies with important methodological limitations, one suggested a stool-softening effect of beta-palmitate whereas the second did not, that one animal study did not support a stool-softening effect of beta-palmitate, and that the evidence provided for a mechanism by which beta-palmitate could contribute to the softening of stools is weak. The Panel concludes that a cause and effect relationship has not been established between the consumption of beta-palmitate and softening of stools.

  15. Higgs ultraviolet softening

    CERN Document Server

    Brivio, I; Gavela, M B; Gonzalez-Garcia, M C; Merlo, L; Rigolin, S

    2014-01-01

    We analyze the leading effective operators which induce a quartic momentum dependence in the Higgs propagator, for a linear and for a non-linear realization of electroweak symmetry breaking. Their specific study is relevant for the understanding of the ultraviolet sensitivity to new physics. Two methods of analysis are applied, trading the Lagrangian coupling by: i) a "ghost" scalar, after the Lee-Wick procedure; ii) other effective operators via the equations of motion. The two paths are shown to lead to the same effective Lagrangian at first order in the operator coefficients. It follows a modification of the Higgs potential and of the fermionic couplings in the linear realization, while in the non-linear one anomalous quartic gauge couplings, Higgs-gauge couplings and gauge-fermion interactions are induced in addition. Finally, all LHC Higgs and other data presently available are used to constrain the operator coefficients; the future impact of $pp\\rightarrow\\text{4 leptons}$ data via off-shell Higgs excha...

  16. Higgs ultraviolet softening

    Science.gov (United States)

    Brivio, I.; Éboli, O. J. P.; Gavela, M. B.; Gonzalez-García, M. C.; Merlo, L.; Rigolin, S.

    2014-12-01

    We analyze the leading effective operators which induce a quartic momentum dependence in the Higgs propagator, for a linear and for a non-linear realization of electroweak symmetry breaking. Their specific study is relevant for the understanding of the ultraviolet sensitivity to new physics. Two methods of analysis are applied, trading the Lagrangian coupling by: i) a "ghost" scalar, after the Lee-Wick procedure; ii) other effective operators via the equations of motion. The two paths are shown to lead to the same effective Lagrangian at first order in the operator coefficients. It follows a modification of the Higgs potential and of the fermionic couplings in the linear realization, while in the non-linear one anomalous quartic gauge couplings, Higgs-gauge couplings and gauge-fermion interactions are induced in addition. Finally, all LHC Higgs and other data presently available are used to constrain the operator coefficients; the future impact of pp → 4 leptons data via off-shell Higgs exchange and of vector boson fusion data is considered as well. For completeness, a summary of pure-gauge and gauge-Higgs signals exclusive to non-linear dynamics at leading-order is included.

  17. Süleyman Demirel Üniversitesi Yerleşkesinin Gürültü Haritalarının Coğrafi Bilgi Sistemleri ile Hazırlanması

    Directory of Open Access Journals (Sweden)

    Nihat MOROVA

    2014-02-01

    Full Text Available Özellikle son yıllarda artan nüfusa paralel olarak kentleşme ve teknolojik gelişmelerin giderek artmasının önemli sonuçlarından biri olan gürültü aynı zamanda önemli bir çevre, yaşam ve sağlık sorunudur. İstenmeyen ve bir anlam ifade etmeyen ses olarak tanımlanan gürültünün insan sağlığı üzerine çeşitli fizyolojik değişiklikler ve performans azalması gibi pek çok etkisi vardır. İletişimin temelini oluşturan karşılıklı konuşma ve bu konuşmanın kalitesi, anlaşılabilirliği, kullanım amacı ne olursa olsun bulunulan tüm mekanlar için öncelikli bir konudur. Bu nedenle özellikle kütüphane ve eğitim kurumlarında gürültü düzeyinin düşük olması istenmektedir. Eğitim kurumlarında öğrenmenin ve öğretmenin temel amaç olduğu düşünülürse, bu amacın gerçekleştirilmesinde hem kurum içi fizik ortam şartlarının ve hem de eğitim kurumlarındaki dersliklere etki eden dış ortam koşullarının bu amaçlar çerçevesinde en optimal değerler arasında olması gerekmektedir. Bu çalışmada; Süleyman Demirel Üniversitesi (SDÜ yerleşkesine ait dış mekanlarda gürültü haritası, Coğrafi Bilgi Sistemleri (CBS ile hazırlanmıştır. Bu amaçla yerleşke içerisinde daha önceden koordinatları belirlenen 96 noktada maksimum (Lmax, minimum (Lmin ve eşdeğer gürültü seviyeleri (Leq, ölçülerek ArcGIS 9.0 yazılımında IDW interpolasyon yöntemi kullanılarak her bir gürültü seviyesi için gürültü haritaları oluşturulmuştur. Hazırlanan bu haritalar Quickbird uydu görüntüsü ile örtüştürülerek Süleyman Demirel Üniversitesinin gürültüden etkilenen alanları belirlenmiştir. Anahtar Kelimeler: Gürültü Kirliliği, Gürültü Haritası, Coğrafi Bilgi Sistemleri, GPS, Süleyman Demirel Üniversitesi

  18. Aplicación de la tomografía computarizada de haz cónico en el diagnóstico de síndrome de Eagle

    Directory of Open Access Journals (Sweden)

    J. Verbel Bohórquez

    2014-12-01

    Full Text Available En la práctica odontológica, cada vez son más comunes las alteraciones con sintomatología dolorosa en la región maxilofacial que no son apropiadamente diagnosticadas, a causa del desconocimiento de síndromes craneofaciales y cervicofaríngeos, como el síndrome de Eagle. Este último se describe como el dolor orofacial relacionado con la elongación de la apófisis estiloide y/o calcificación del ligamento estilohioideo. La aparición de una patología asociada a tal estructura, está acompañada de otros síntomas como: disfonía, disfagia, dolor faríngeo, glositis, otalgia, tonsilitis, dolor facial, cefalea, odinofagia, dolor en la articulación temporomandibular e imposibilidad de realizar movimientos laterales del cuello. El presente artículo es una revisión bibliográfica cuyo objetivo consistió en describir los aspectos generales del Síndrome de Eagle y la aplicabilidad de ayudas imagenológicas actuales en su identificación y diagnóstico. Se realizó una búsqueda de literatura en bases de datos como: MEDLINE (Ovid, Pubmed, Science Direct, y scirus empleando descriptores como: Eagle syndrome, cone beam, styloid process, Eagle syndrome in dentistry. A partir de la búsqueda se seleccionaron 37 artículos. Finalmente se pudo concluir que entre los diversos métodos diagnósticos, el que permite un análisis detallado de los patrones radiográficos de síndrome de Eagle, es la tomografía computarizada de haz cónico (Cone Beam Coputed Tomography.

  19. Cyclic behaviors of amorphous shape memory polymers.

    Science.gov (United States)

    Yu, Kai; Li, Hao; McClung, Amber J W; Tandon, Gyaneshwar P; Baur, Jeffery W; Qi, H Jerry

    2016-04-01

    Cyclic loading conditions are commonly encountered in the applications of shape memory polymers (SMPs), where the cyclic characteristics of the materials determine their performance during the service life, such as deformation resistance, shape recovery speed and shape recovery ratio. Recent studies indicate that in addition to the physical damage or some other irreversible softening effects, the viscoelastic nature could also be another possible reason for the degraded cyclic behavior of SMPs. In this paper, we explore in detail the influence of the viscoelastic properties on the cyclic tension and shape memory (SM) behavior of an epoxy based amorphous thermosetting polymer. Cyclic experiments were conducted first, which show that although the epoxy material does not have any visible damage or irreversible softening effect during deformation, it still exhibits obvious degradation in the cyclic tension and SM behaviors. A linear multi-branched model is utilized to assist in the prediction and understanding of the mechanical responses of amorphous SMPs. Parametric studies based on the applied model suggest that the shape memory performance can be improved by adjusting programming and recovery conditions, such as lowering the loading rate, increasing the programming temperature, and reducing the holding time.

  20. Behavior of exposed human lymphocytes to a neutron beam of the reactor TRIGA Mark III; Comportamiento de linfocitos humanos expuestos a un haz de neutrones del reactor Triga Mark III

    Energy Technology Data Exchange (ETDEWEB)

    Carbajal R, M. I.

    2012-07-01

    Excessive exposure to ionizing radiation occurs in people who require radiation treatment, also in those for work can come to receive doses above the permitted levels. A third possibility of exposure is the release of radioactive material in which the general population is affected. Most of the time the exhibition is partial and only rarely occurs throughout the body. For various reasons, situations arise where it is impossible to determine by conventional physical methods, the amount of radiation you were exposed to the affected person and in these cases where the option to follow is the Biological Dosimetry, where the analysis of chromosomes dicentrics is used to estimate the dose of ionizing radiation exposure. A calibration curve is generated from in vitro analysis of dicentric chromosome, which are found in human lymphocytes, treated with different types and doses of radiation. The dicentric is formed from two lesions, one on each chromosome and their union results in a structure having two centromeres, acentric fragment with her for the union of several chromosomes leads to more complex structures as tri-centric s, tetra or penta-centric s, which have the same origin. The dose-response curve is estimated by observing the frequency of dicentrics and extrapolated to a dose-effect curve previously established, for which it is necessary that each lab has its own calibration curves, taking into account that for a Let low radiation, dose-effect curve follows a linear-quadratic model Y=C + {alpha}D + {beta}D. The production of dicentric chromosomes with a high Let, was studied using a beam of neutrons generated in the reactor TRIGA Mark III with an average energy of 1 MeV, adjusting the linear model Y={alpha}D. The dose-response relationship is established in blood samples from the same donor, the coefficient {alpha} of the dose-response is Y = (0.3692 {+-} 0.011 * D), also shows that saturation is reached in system 4 Gy. (Author)

  1. Firmness at Harvest Impacts Postharvest Fruit Softening and Internal Browning Development in Mechanically Damaged and Non-damaged Highbush Blueberries (Vaccinium corymbosum L.)

    Science.gov (United States)

    Moggia, Claudia; Graell, Jordi; Lara, Isabel; González, Guillermina; Lobos, Gustavo A.

    2017-01-01

    Fresh blueberries are very susceptible to mechanical damage, which limits postharvest life and firmness. Softening and susceptibility of cultivars “Duke” and “Brigitta” to developing internal browning (IB) after mechanical impact and subsequent storage was evaluated during a 2-year study (2011/2012, 2012/2013). On each season fruit were carefully hand-picked, segregated into soft (<1.60 N), medium (1.61–1.80 N), and firm (1.81–2.00 N) categories, and then either were dropped (32 cm) onto a hard plastic surface or remained non-dropped. All fruit were kept under refrigerated storage (0°C and 85–88% relative humidity) to assess firmness loss and IB after 7, 14, 21, 28, and 35 days. In general, regardless of cultivar or season, high variability in fruit firmness was observed within each commercial harvest, and significant differences in IB and softening rates were found. “Duke” exhibited high softening rates, as well as high and significant r2 between firmness and IB, but little differences for dropped vs. non-dropped fruit. “Brigitta,” having lesser firmness rates, exhibited almost no relationships between firmness and IB (especially for non-dropped fruit), but marked differences between dropping treatments. Firmness loss and IB development were related to firmness at harvest, soft and firm fruit being the most and least damaged, respectively. Soft fruit were characterized by greater IB development during storage along with high soluble solids/acid ratio, which could be used together with firmness to estimate harvest date and storage potential of fruit. Results of this work suggest that the differences in fruit quality traits at harvest could be related to the time that fruit stay on the plant after turning blue, soft fruit being more advanced in maturity. Finally, the observed differences between segregated categories reinforce the importance of analyzing fruit condition for each sorted group separately. PMID:28443123

  2. 黏弹性阻尼器温度软化效应补偿控制%Compensation Control of Thermal Softening Effect for Viscoelastic Dampers

    Institute of Scientific and Technical Information of China (English)

    刘文斌; 涂建维

    2016-01-01

    A strategy for compensation and control of thermal softening effect for a new kind of viscoelastic dampers is proposed. By inputting proper control current to the damper according to the real-time temperature, the softening effect of the damper at high temperature can be compensated. Therefore, intelligent control devices are the core of the damper compensation control. In this paper, a thermal compensation intelligent control device based on pulse width modulation technique is developed. The results show that this intelligent control device is of high accuracy and the thermal softening effect can be compensated well by this control strategy. The control accuracy and the compensation effect can meet the actual engineering needs of the dampers.%提出新型黏弹性阻尼器温度软化效应的补偿与控制策略,通过控制试验检验智能控制器精度及温度软化效应补偿控制效果。据此研制出基于脉宽调制技术的温度补偿智能控制器,结果表明,智能控制器精度较高,所提出的温度补偿控制策略可以很好地补偿黏弹性阻尼器温度软化效应,控制器精度与补偿效果均能满足阻尼器实际工作要求。

  3. Fluffy and softening finishes of hemp/cotton mixture fabrics%大麻/彩棉交织物蓬松柔软整理

    Institute of Scientific and Technical Information of China (English)

    奚杨; 姜凤琴

    2011-01-01

    To improve the flexibility and the feeling of hemp/cotton mixture fabrics, weak cationic softener and fluffy agents were used to process the mixture fabrics. Flexural rigidity was used as main evaluation index. Regression equation was made through quadratic regression orthogonal and the best ratio of softener and fluffy agents was calculated. The result demonstrated that the mass concentration of softener is 7. 656 g/L and the mass concentration of fluffy agents is 6. 862%. After treatment, the stiffness decreased significantly and the flexibility is increased significantly but the loss of strength is very small.%为了提高大麻/彩棉交织物的柔软度,分别选用弱阳离子型柔软剂和阳离子型蓬松片对织物进行处理,以抗弯刚度为主要评价指标.考虑到柔软剂与蓬松片的交互作用,通过二次回归正交试验建立回归方程,确定交互作用下试剂的最佳浓度.通过对处理前后交织物的断裂强力、断裂伸长及手感进行对比分析最后得出最佳整理工艺:柔软剂的质量浓度为7.656 g/L,蓬松片的质量分数为6.862%.经蓬松柔软处理的大麻/彩棉交织物,硬挺度明显下降,手感丰满、滑糯,柔软度明显增加且强力损失较小.

  4. Low-Temperature Softening Due to Vacancy Orbital with Γ8 Quartet Ground State in Boron-Doped Floating Zone Silicon

    Science.gov (United States)

    Baba, Shotaro; Akatsu, Mitsuhiro; Mitsumoto, Keisuke; Komatsu, Satoru; Horie, Kunihiko; Nemoto, Yuichi; Yamada-Kaneta, Hiroshi; Goto, Terutaka

    2013-08-01

    We have carried out low-temperature ultrasonic measurements using shear-mode ultrasound to clarify the quantum state of a vacancy orbital in boron-doped silicon grown by the floating zone (FZ) method. The elastic constants (C11-C12)/2 and C44 of the transverse mode exhibit considerable softening below 2 and 5 K down to the base temperature of 30 mK, respectively. The elastic constant C44 measured by the three ultrasonic modes (kx,uy), (kz,ux), and (kx,uz) shows the different magnetic field dependences among the configurations under applied magnetic fields along the z-axis. The elastic softening and the magnetic field dependence of the elastic constants are accounted for by the quadrupole susceptibility based on the energy level scheme of the vacancy orbital with a Γ8 quartet ground state and Γ7 doublet excited state located at an energy of 1 K. The difference in C44 between the two ultrasonic modes (kz,ux) and (kx,uz) at fields along the z-axis indicates that the Γ8 quartet ground state is slightly split by local strain in the silicon sample. The quantum state of the vacancy orbital is expected to be sensitive to strain because of the extremely large quadrupole-strain coupling energy of gΓ≈ 105 K due to the extensively spreading orbital radius of r≈ 1 nm. The differences in variation of the low-temperature softening and magnetic field dependence among eight samples cut out from different locations of the present boron-doped FZ silicon ingot evidence the inhomogeneous distribution of the vacancy concentration.

  5. Phonon softening and lattice melting at the ferroelastic phase transition in Na2CO3

    DEFF Research Database (Denmark)

    Harris, M.J.; McMorrow, D.F.; Godfrey, K.W.

    1997-01-01

    We present the results of a detailed inelastic neutron scattering study of the dynamics of the ferroelastic phase transition in Na2Co3. The driving instability is a transverse acoustic mode that softens over a plane of wave vectors, resulting in a continuous loss of long-range order, in accord...... with theoretical predictions, At T-c a wide distribution of excitations is observed in the plane of critical wave vectors, similar to the dynamics of a liquid. Perpendicular to this plane the system possesses one-dimensional order....

  6. The transition from stress softening to stress hardening under cyclic loading induced by magnetic field for magneto-sensitive polymer gels

    Science.gov (United States)

    Xu, Yangguang; Liao, Guojiang; Zhang, Canyang; Wan, Qiang; Liu, Taixiang

    2016-04-01

    Magneto-sensitive polymer gel (MSPG) is a kind of ferromagnetic particle filled smart polymer composite, whose magneto-mechanical coupling mechanism has attracted increasing attention in recent years. In this work, the magneto-induced rheological response of MSPG under cyclic shear loading was investigated. It was found that magnetic field is the critical reason for the transition from stress softening to stress hardening under cyclic loading. Besides, the particle concentration and temperature are the controlling factors in the structure optimization of MSPG in the presence of magnetic field. The magneto-induced hardening mechanism was further proposed based on the related experimental results.

  7. Determination of Softening Traction-Separation Laws after Exposure to High Temperature%高温后混凝土软化本构曲线的确定

    Institute of Scientific and Technical Information of China (English)

    俞可权; 陆洲导

    2013-01-01

    Wedge-splitting tests of the concrete specimens after exposure to high temperature were conducted.Adopting three bilinear softening curves at room temperature and taking account of the quantitative relationship among unstable fracture toughness KIC T,initial fracture toughness KIC,ini.T and cohesive fracture toughness KIC,c,T from the double-K fracture model,the relationship of these three parameters for the concrete after exposure to high temperature was investigated.There are two cases of calculation of cohesive fracture toughness KIC,.T,and the similar values of KIC,c,T are obtained from the calculation using different softening curves.The calculated unstable fracture toughness KIC Tbased on the three softening curves has a good coincidence with the experimental value,which shows that the softening curves could well reflect the real fracture feature of the concrete after exposure to high temperature and the adaptability of application of double-K fracture model to the concrete after exposure to high temperature is proved.%结合高温后混凝土楔入劈拉法试验,采用3种常温下混凝土双线性软化本构曲线,借鉴常温下双K断裂模型中失稳韧度KIC,un,T与黏聚韧度KIC,c,T,起裂韧度KIC,ini,T间的定量关系,对高温后混凝土断裂韧度间的关系进行研究.结果表明:高温后黏聚韧度KIC,c,T的计算分为2种情况,用不同软化曲线计算得到的黏聚韧度值相近;由3种常温下的软化曲线计算得到的失稳断裂韧度值与实测失稳断裂韧度值能够较好吻合,现有软化曲线能较好地反映高温后混凝土断裂性能;同时验证了双K断裂模型对高温后混凝土的适用性.

  8. Adjustable rheology of fumed silica dispersion in urethane prepolymers: Composition-dependent sol and gel behaviors and energy-mediated shear responses

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Zhong, E-mail: 11329038@zju.edu.cn; Song, Yihu, E-mail: s-yh0411@zju.edu.cn; Wang, Xiang, E-mail: 11229036@zju.edu.cn; Zheng, Qiang, E-mail: zhengqiang@zju.edu.cn [MOE Key Laboratory of Macromolecule Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027 (China)

    2015-07-15

    Variation of colloidal and interfacial interactions leads to a microstructural diversity in fumed silica dispersions exhibiting absolutely different sol- or gel-like rheological responses. In this study, fumed silicas with different surface areas (200–400 m{sup 2}/g) and surface characteristics (hydrophilic or hydrophobic) are dispersed into moisture-cured polyurethane. The microstructures investigated using transmission electron microscope are associated perfectly with three different rheological behaviors: (i) Sols with well-dispersed silica aggregates, (ii) weak gels with agglomerate-linked networks, and (iii) strong gels with concentrated networks of large agglomerates. Though sols and gels are well distinguished by shear thickening or sustained thinning response through steady shear flow test, it is interesting that the sols and weak gels exhibit a uniform modulus plateau-softening-hardening-softening response with increasing dynamic strain at frequency 10 rad s{sup −1} while the strong gels show a sustained softening beyond the linear regime. Furthermore, the onset of softening and hardening can be normalized: The two softening are isoenergetic at mechanical energies of 0.3 J m{sup −3} and 10 kJ m{sup −3}. On the other hand, the hardening is initiated by a critical strain of 60%. The mechanisms involved in the generation of the sol- and the gel-like dispersions and their structural evolutions during shear are thoroughly clarified in relation to the polyols, the characteristic and content of silica and the curing catalysts.

  9. Haz-Mat Refresher: Chemical Precautions

    Science.gov (United States)

    Caliendo, Louis A.

    2012-01-01

    It is important that first responders remain aware of the possible hazards resulting from chemical accidents or the intentional use of chemicals in destructive devices. Chemical components can be utilized in the manufacturing of improvised explosive devices (IEDs), can enhance the effect of a more conventional device, or can pose hazards based on…

  10. Modeling high temperature materials behavior for structural analysis

    CERN Document Server

    Naumenko, Konstantin

    2016-01-01

    This monograph presents approaches to characterize inelastic behavior of materials and structures at high temperature. Starting from experimental observations, it discusses basic features of inelastic phenomena including creep, plasticity, relaxation, low cycle and thermal fatigue. The authors formulate constitutive equations to describe the inelastic response for the given states of stress and microstructure. They introduce evolution equations to capture hardening, recovery, softening, ageing and damage processes. Principles of continuum mechanics and thermodynamics are presented to provide a framework for the modeling materials behavior with the aim of structural analysis of high-temperature engineering components.

  11. Cavitation erosion behavior of nickel-aluminum bronze weldment

    Institute of Scientific and Technical Information of China (English)

    李小亚; 闫永贵; 许振明; 李建国

    2003-01-01

    Cavitation erosion behavior of nickel-aluminum bronze(NAB)weldment in 3.5% NaCl aqueous solution was studied by magnetostrictive vibratory device for cavitation erosion.The results show that cavitation erosion resistance of the weld zone(WZ)of the weldment is superior to that of the base metal.SEM observation of eroded specimens reveals that the phases undergoing selective attack by the stress of cavitation erosion at the early stage of cavitation erosion are:martensite in the WZ,α phase in the heat-affected zone(HAZ)and eutectoidal phase in the base metal; the microcracks causing cavitation damage initiate at the phase boundaries.

  12. Influence of Temperature on Mechanical Behavior During Static Restore Processes of Al-Zn-Mg-Cu High Strength Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    ZHANG Kun

    2017-06-01

    Full Text Available Flow stress behaviors of as-cast Al-Zn-Mg-Cu high strength aluminum alloy during static restore processes were investigated by: Isothermal double-pass compression tests at temperatures of 300-400℃, strain rates of 0.01-1 s-1, strains of 33% +20% with the holding times of 0~900 s after the first pass compression. The results indicate that the deformation temperature has a dramatical effect on mechanical behaviors during static restore processes of the alloy. (1 At 300 ℃ and 330 ℃ lower temperatures, the recovery during the deformation is slow, and deformation energy stored in matrix is higher, flow stresses at the second pass deformation decreased during the recovery and recrystallization, and the stress softening phenomena is observed. Stress softening is increased with the increasing holding time; Precipitation during the holding time inhibites the stress softening. (2 At 360 ℃ and 400 ℃ higher temperatures, the recovery during deformation is rapid, and deformation energy stored in matrix is lower. Solid solubility is higher after holding, so that flow stress at the second pass deformation is increased, stress hardening phenomena is observed. Stress hardening decreased with the increasing holding time duo to the recovery and recrystallization during holding period at 360 ℃; Precipitation during holding also inhibited the stress softening. However, Stress hardening remains constant with the increasing holding time duo to the reasanenal there are no recovery and recrystallization during holding period at 400 ℃.

  13. Enhancement of the superconducting transition temperature of MgB2 by a strain-induced bond-stretching mode softening.

    Science.gov (United States)

    Pogrebnyakov, A V; Redwing, J M; Raghavan, S; Vaithyanathan, V; Schlom, D G; Xu, S Y; Li, Qi; Tenne, D A; Soukiassian, A; Xi, X X; Johannes, M D; Kasinathan, D; Pickett, W E; Wu, J S; Spence, J C H

    2004-10-01

    We report a systematic increase of the superconducting transition temperature T(c) with a biaxial tensile strain in MgB2 films to well beyond the bulk value. The tensile strain increases with the MgB2 film thickness, caused primarily by the coalescence of initially nucleated discrete islands (the Volmer-Weber growth mode.) The T(c) increase was observed in epitaxial films on SiC and sapphire substrates, although the T(c) values were different for the two substrates due to different lattice parameters and thermal expansion coefficients. We identified, by first-principles calculations, the underlying mechanism for the T(c) increase to be the softening of the bond-stretching E(2g) phonon mode, and we confirmed this conclusion by Raman scattering measurements. The result suggests that the E(2g) phonon softening is a possible avenue to achieve even higher T(c) in MgB2-related material systems.

  14. CoF2: a model system for magnetoelastic coupling and elastic softening mechanisms associated with paramagnetic ↔ antiferromagnetic phase transitions.

    Science.gov (United States)

    Thomson, R I; Chatterji, T; Carpenter, M A

    2014-04-01

    Resonant ultrasound spectroscopy has been used to monitor variations in the elastic and anelastic behaviour of polycrystalline CoF2 through the temperature interval 10-290 K and in the frequency range ∼0.4-2 MHz. Marked softening, particularly of the shear modulus, and a peak in attenuation occur as the Néel point (TN=39 K) is approached from both high and low temperatures. Although the effective thermodynamic behaviour can be represented semiquantitatively with a Bragg-Williams model for a system with spin 1/2, the magnetoelastic coupling follows a pattern which is closely analogous to that of a Landau tricritical transition which is co-elastic in character. Analysis of lattice parameter data from the literature confirms that linear spontaneous strains scale with the square of the magnetic order parameter and combine to give effective shear and volume strains on the order of 1‰. Softening of the shear modulus at T>TN is attributed to coupling of acoustic modes with dynamical local ordering of spins and can be represented by a Vogel-Fulcher expression. At Tmechanism is attributed to spin-lattice relaxations under the influence of externally applied dynamic shear stress. CoF2 provides a reference or end-member behaviour against which the likely antiferromagnetic component of magnetoelastic behaviour in more complex multiferroic materials, with additional displacive instabilities, Jahn-Teller effects and ferroelastic microstructures, can be compared.

  15. Matrix Metalloproteinase 2 (MMP-2) Plays a Critical Role in the Softening of Common Carp Muscle during Chilled Storage by Degradation of Type I and V Collagens.

    Science.gov (United States)

    Xu, Chao; Wang, Cheng; Cai, Qiu-Feng; Zhang, Qian; Weng, Ling; Liu, Guang-Ming; Su, Wen-Jin; Cao, Min-Jie

    2015-12-30

    Matrix metalloproteinases (MMPs) are proposed to play important roles in the degradation of collagens, thus causing the post-mortem softening of fish muscle, although the specific mechanism remains largely unresolved. Previously, we reported the existence of gelatinase-like proteinases in common carp (Cyprinus carpio) muscle. The primary structures of these proteinases, however, have never been investigated. In the present study, two MMPs with molecular masses of 66 and 65 kDa were purified to homogeneity from common carp muscle by ammonium sulfate fractionation and a series of column chromatographies. Matrix-assisted laser desorption/ionization-tandem time-of-flight mass spectrometry (MALDI-TOF/TOF-MS/MS) analysis indicated that they are completely identical to MMP-2 from common carp. During chilled storage of common carp at 4 °C, the enzymatic activity of MMP-2 increased to 212% in 12 h while the texture profile increased over the first 2 h and gradually decreased. On the other hand, type V collagen was purified to homogeneity and a specific polyclonal antibody against this protein was prepared. Both type I and V collagens were effectively hydrolyzed by MMP-2 at 30 °C and even at 4 °C. Furthermore, injection of metalloproteinase proteinase inhibitor EDTA into the blood vessel of live common carp suppressed post-mortem tenderization significantly. All of these results confirmed that MMP-2 is a major proteinase responsible for the degradation of collagens, resulting in the softening of fish muscle during chilled storage.

  16. Suppression of the Structural Phase Transition and Lattice Softening in Slightly Underdoped Ba1−xKxFe2As2 with Electronic Phase Separation

    Energy Technology Data Exchange (ETDEWEB)

    Inosov, D.; Leineweber, A; Yang, X; Park, J; Christensen, N; Dinnebier, R; Sun, G; Niedermayer, C; Haug, H; et. al.

    2009-01-01

    We present x-ray powder diffraction (XRPD) and neutron-diffraction measurements on the slightly underdoped iron-pnictide superconductor Ba1-xKxFe2As2, Tc=32 K. Below the magnetic-transition temperature Tm=70 K, both techniques show an additional broadening of the nuclear Bragg peaks, suggesting a weak structural phase transition. However, macroscopically the system does not break its tetragonal symmetry down to 15 K. Instead, XRPD patterns at low temperature reveal an increase in the anisotropic microstrain proportionally in all directions. We associate this effect with the electronic phase separation previously observed in the same material and with the effect of lattice softening below the magnetic phase transition. We employ density-functional theory to evaluate the distribution of atomic positions in the presence of dopant atoms both in the normal and magnetic states and to quantify the lattice softening, showing that it can account for a major part of the observed increase in the microstrain.

  17. Alkali modification and softening finish of hemp yarn%大麻纱线的碱改性柔软整理

    Institute of Scientific and Technical Information of China (English)

    鞠金星; 王宝权; 吕站逵; 季英超

    2012-01-01

    针对大麻纱在针织机上生产时存在编织成圈困难的问题,提出了对大麻纱线进行柔软处理以提高其可编织性的方法.用氢氧化钠对大麻纱线进行改性,结合柔软剂进行柔软处理的方法降低大麻纱线的刚性,并采用正交试验的方法,确定了碱改性的最佳工艺:碱液质量浓度l00g/L,温度20℃,浸渍时间15min,浴比1:20.结合柔软剂整理可明显降低大麻纱线刚性,提高纯大麻纱线的上机编织效果.%The soft hemp yarn processing was studies to enhance their weave performance. Alkali modification together with treatment of caustic soda and softener was used for reducing the stiffness of hemp yarn. The result indicates that the best technological conditions were: alkali concentration 100 g/L, temperature 20 ℃ , soaking time is 15 min, liquor ratio 1 : 20. The treatment with softening agent can obviously reduce the stiffness of hemp yarn and improve its knitting performance.

  18. Softening temperature of lyophilized bovine serum albumin and gamma-globulin as measured by spin-spin relaxation time of protein protons.

    Science.gov (United States)

    Yoshioka, S; Aso, Y; Kojima, S

    1997-04-01

    We investigated the usefulness of the spin-spin relaxation time (T2) of protein protons as a probe for evaluating the molecular flexibility of freeze-dried protein formulations. It is proposed that the microscopic softening temperature determined from changes in the T2 of protein protons (Ts(T2)) is an important characteristic of freeze-dried protein formulations, the glass transition temperature (Tg) of which is generally difficult to determine by differential scanning calorimetry. We determined the molecular flexibility of lyophilized bovine serum albumin (BSA) and bovine gamma-globulin (BGG) by measuring the T2 of protein and water protons as well as the spin-lattice relaxation time (T1) of the latter as a function of temperature. The flexibility of freeze-dried BSA and BGG cakes markedly varied at temperatures above and below the Ts(T2), affecting the stability of the proteins. The denaturation and subsequent aggregation of lyophilized BSA and BGG cakes with a relatively high water content was enhanced in the softened state at temperatures above the Ts(T2). Lyophilized cakes with an extremely low water content were significantly denatured, even in the unsoftened state at temperatures below the Ts(T2), probably due to the thermodynamically unstable structures of protein molecules generated by a loss of structural water.

  19. A proposed food breakdown classification system to predict food behavior during gastric digestion.

    Science.gov (United States)

    Bornhorst, Gail M; Ferrua, Maria J; Singh, R Paul

    2015-05-01

    The pharmaceutical industry has implemented the Biopharmaceutics Classification System (BCS), which is used to classify drug products based on their solubility and intestinal permeability. The BCS can help predict drug behavior in vivo, the rate-limiting mechanism of absorption, and the likelihood of an in vitro-in vivo correlation. Based on this analysis, we have proposed a Food Breakdown Classification System (FBCS) framework that can be used to classify solid foods according to their initial hardness and their rate of softening during physiological gastric conditions. The proposed FBCS will allow for prediction of food behavior during gastric digestion. The applicability of the FBCS framework in differentiating between dissimilar solid foods was demonstrated using four example foods: raw carrot, boiled potato, white rice, and brown rice. The initial hardness and rate of softening parameter (softening half time) were determined for these foods as well as their hypothesized FBCS class. In addition, we have provided future suggestions as to the methodological and analytical challenges that need to be overcome prior to widespread use and adoption of this classification system. The FBCS gives a framework that may be used to classify food products based on their material properties and their behavior during in vitro gastric digestion, and may also be used to predict in vivo food behavior. As consumer demand increases for functional and "pharma" food products, the food industry will need widespread testing of food products for their structural and functional performance during digestion.

  20. Exploring the high-pressure behavior of superhard tungsten tetraboride

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Miao; Mohammadi, Reza; Mao, Zhu; Armentrout, Matt M.; Kavner, Abby; Kaner, Richard B.; Tolbert, Sarah H. (UCLA)

    2016-07-29

    In this work, we examine the high-pressure behavior of superhard material candidate WB{sub 4} using high-pressure synchrotron x-ray diffraction in a diamond anvil cell up to 58.4 GPa. The zero-pressure bulk modulus, K{sub 0}, obtained from fitting the pressure-volume data using the second-order Birch-Murnaghan equation of state is 326 {+-} 3 GPa. A reversible, discontinuous change in slope in the c/a ratio is further observed at {approx}42 GPa, suggesting that lattice softening occurs in the c direction above this pressure. This softening is not observed in other superhard transition metal borides such as ReB{sub 2} compressed to similar pressures. Speculation on the possible relationship between this softening and the orientation of boron-boron bonds in the c direction in the WB{sub 4} structure is included. Finally, the shear and Young's modulus values are calculated using an isotropic model based on the measured bulk modulus and an estimated Poisson's ratio for WB{sub 4}.

  1. EFFECT OF MICROSTRUCTURE ON THE HARDENING AND SOFTENING BEHAVIORS OF POLYCRYSTALLINE SHAPE MEMORY ALLOYS PART II: NUMERICAL SIMULATION UNDER AXISYMMETRICAL LOADING

    Institute of Scientific and Technical Information of China (English)

    Song Guquan; Sun Qingping; Hwang Kehchih

    2000-01-01

    Based on the microstructure-based constitutive model established in Part I, a detailed numerical investigation on the role of each microstructure parameter in the kinematical and kinetic evolution of polycrystalline SMA under axisymmetrical tension loading is performed. Some macroscopic constitutive features of stress-induced martensite transformation are discussed.

  2. Cracking and load-deformation behavior of fiber reinforced concrete: Influence of testing method

    DEFF Research Database (Denmark)

    Paegle, Ieva; Minelli, Fausto; Fischer, Gregor

    2016-01-01

    on the definition of measured and derived parameters, including toughness, elastic properties and strength. This paper discusses a number of test procedures for selected material properties including tension and flexure. A comparative experimental study was carried out using two distinct fiber reinforced...... cementitious composites with strain hardening and strain softening behavior. Digital Image Correlation was utilized in the experimental program to detect and quantify the formation of cracks. Results show that the different test methodologies valuate specific aspects of material performance. The outcome...

  3. Evaluation of a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate to repair acid-softened enamel using an intra-oral remineralization model.

    Science.gov (United States)

    Sullivan, R; Rege, A; Corby, P; Klaczany, G; Allen, K; Hershkowitz, D; Goldder, B; Wolff, M

    2014-01-01

    An intra-oral remineralization study was conducted to compare the ability of a dentifrice containing 8% arginine and calcium carbonate (Pro-Argin Technology), and 1450 ppm fluoride as sodium monofluorophosphate (MFP) to remineralize acid-softened bovine enamel specimens compared to a silica-based dentifrice with 1450 ppm fluoride as MFP. The intra-oral clinical study employed a double blind, two-treatment, crossover design, and used an upper palatal retainer to expose the enamel specimens to the oral environment during product use and periods of remineralization. The retainer was designed to house three partially demineralized bovine enamel samples. The study population was comprised of 30 adults, ages 18 to 70 years. The study consisted of two treatment phases with a washout period lasting seven (+/- three) days preceding each treatment phase. A silica-based dentifrice without fluoride was used during the washout period. The Test Dentifrice used in this study contained 8% arginine, calcium carbonate, and 1450 ppm fluoride as sodium monofluorophosphate (MFP). The Control Dentifrice was silica-based and contained 1450 ppm fluoride as MFP. The treatment period consisted of a three-day lead-in period with the assigned product. The panelists brushed two times per day during the three-day lead-in period with the assigned product. On the fourth day, the panelists began brushing with the assigned product with the retainer in their mouth. The panelists brushed for one minute, followed by a one-minute swish with the slurry and a rinse with 15 ml of water in the morning, in the afternoon, and night with the retainer in the mouth. The panelists brushed only their teeth and not the specimens directly. Changes in mineral content before and after treatment were measured using a Knoop microhardness tester. The results of the study showed that percent remineralization values for the Test Dentifrice and Control Dentifrice were 14.99% and 8.66%, respectively. A statistical analysis

  4. Phonon Softening in PrFeAsO1-y (y˜0.2) by Inelastic X-Ray Scattering

    Science.gov (United States)

    Baron, Alfred Q. R.; Fukuda, Tatsuo; Shamoto, Shin-Ichi; Uchiyama, Hiroshi; Mizuki, Jun-Ichiro; Nakamura, Hiroki; Machida, Masahiko; Ishikado, Motoyuki; Arai, Masatoshi; Kito, Hijiri; Eisaki, Hiroshi

    2009-03-01

    We present phonon dispersion measurements from single crystals of PrFeAsO1-y with Tc (onset) of 42 to 45 K made using inelastic x-ray scattering with 1.5 meV resolution at BL35XU of SPring-8. In agreement with our previous results on powders and crystals [1] we see pronounced softening of the in-plane Fe-As modes compared to phonon calculations using pseudopotential methods in the tetragonal (non-magnetic) structure. C-axis modes are somewhat harder. No strong changes in phonon spectra across Tc were observed at the momentum transfers investigated. We also compare our results against calculations of phonons in the magnetic parent material. [1] Fukuda, et al, J. Phys. Soc. Japan, 77 (2008), 103715.

  5. 榛子木质化花柱软化方法的改进%Improvement of Lignified Style Softening Method in Hazelnut

    Institute of Scientific and Technical Information of China (English)

    程云清; 张会弟; 刘剑锋

    2015-01-01

    以野生平榛( C。heterophylla Fisch。)雌花序为供试材料,研究榛子木质化花柱软化的方法。结果表明:(1)1。0 mol/L NaOH溶液浸泡并煮沸比相同处理下蒸馏水的软化效果好;(2)1。0 mol/L NaOH溶液浸泡材料并立即水煮软化20 min后的软化效果优于其他处理时间;(3)苯胺蓝染色环境的缓冲液最佳pH范围为5。7至7。1。此改进方法可以在一天内即可完成榛子花粉管形态的观察,较传统软化方法简单、快捷。%Pistilate flower of wild hazelnut ( C.heterophylla Fisch.) was used as study materials to improve style softening method.The results showed that:(1) 1.0 mol/L boiling NaOH solution soaking was more beneficial for softening of style compared with boiling distilled water;(2) the optimal treatment time was 20 min in 1.0 mol/L boiling NaOH solution;(3) The suitable buffer pH of aniline blue solution ranged from 5.7 to 7.1.After improvement,morphology of pollen tubes of hazelnut could be observed clearly within one day .Thus,this method is more simple and efficient than the traditional one .

  6. Study on softening Tilapia backbone by high pressure steam cooking%高压蒸煮软化罗非鱼鱼骨的研究

    Institute of Scientific and Technical Information of China (English)

    吴克刚; 张文祥; 柴向华; 何文龙

    2013-01-01

    To study softening Tilapia backbone by high pressure steam cooking,with pH,cooking pressure,steaming time and material/water ratio for study factors,the hardness of Tilapia backbone was evaluated with its maximum bearable pressure on universal testing machine.Results of single-factor experiments and orthogonal experiments showed that the softening effect of backbone was the best with the treatment condition of pH6.5,pressure of 0.13MPa,steaming time of 75min and material/water ratio of 1∶1.Under this condition,the hardness of Tilapia backbone was 33.0N.%以罗非鱼鱼骨为实验对象,以pH、蒸煮压力、蒸煮时间以及料液比为研究因素,采用万能试验机测量鱼骨最大承受压力来评价其硬度,研究高压蒸煮软化工艺.通过单因素实验及正交实验表明:当pH为6.5、蒸煮压力为0.13MPa、时间为75min、料液比为1∶1时,对鱼骨的软化效果最好,此工艺下所得鱼骨硬度为33.0N.

  7. Effects of Al2O3 and MgO on Softening, Melting, and Permeation Properties of CaO-FeO-SiO2 on a Coke Bed

    Science.gov (United States)

    Ueda, Shigeru; Kon, Tatsuya; Miki, Takahiro; Kim, Sun-Joong; Nogami, Hiroshi

    2016-08-01

    In ironmaking, maintaining gas permeability in blast furnace with low coke rate operation is essential to reduce carbon emissions. The high pressure loss in the cohesive zone decreases the gas permeability and affects the productivity of blast furnace. In order to increase the gas permeability in the cohesive zone, the thickness of the cohesive layer should be decreased. For this purpose, increasing softening temperature and decreasing dripping temperature of the iron ore are desired. In this study, softening, melting, and permeation of SiO2-FeO-CaO-Al2O3-MgO on a coke bed were investigated. The oxide sample in a tablet form was heated under CO/CO2 atmosphere, and the shape of the tablet was observed. The softening and melting temperatures of the SiO2-FeO-CaO system changed with the addition of Al2O3 and MgO. Oxide tablets with and without Al2O3 softened below and above the solidus temperature, respectively. The melting temperatures varied with the ratio of CO/CO2 in the gas. The permeation temperature was independent of the melting temperature, but dependent on the wettability.

  8. Map position and functional allelic diversity of Md-Exp7, a new putative expansin gene associated with fruit softening in apple (Malus x domestica Borkh.) and pear (Pyrus communis)

    NARCIS (Netherlands)

    Costa, F.; Weg, van de W.E.; Stella, S.; Dondini, L.; Pratesi, D.; Musacchi, S.; Sansavini, S.

    2008-01-01

    Fruit ripening can be considered as a complex set of biochemical and physiological changes occurring at the end of the developmental stage. Ripe fruit texture notably affects overall quality and consumer appreciation. Excessive softening limits shelf-life and storability, thereby increasing disease

  9. Non-Gaussian Stochastic Equivalent Linearization Method for Inelastic Nonlinear Systems with Softening Behaviour, under Seismic Ground Motions

    Directory of Open Access Journals (Sweden)

    Francisco L. Silva-González

    2014-01-01

    Full Text Available A non-Gaussian stochastic equivalent linearization (NSEL method for estimating the non-Gaussian response of inelastic non-linear structural systems subjected to seismic ground motions represented as nonstationary random processes is presented. Based on a model that represents the time evolution of the joint probability density function (PDF of the structural response, mathematical expressions of equivalent linearization coefficients are derived. The displacement and velocity are assumed jointly Gaussian and the marginal PDF of the hysteretic component of the displacement is modeled by a mixed PDF which is Gaussian when the structural behavior is linear and turns into a bimodal PDF when the structural behavior is hysteretic. The proposed NSEL method is applied to calculate the response of hysteretic single-degree-of-freedom systems with different vibration periods and different design displacement ductility values. The results corresponding to the proposed method are compared with those calculated by means of Monte Carlo simulation, as well as by a Gaussian equivalent linearization method. It is verified that the NSEL approach proposed herein leads to maximum structural response standard deviations similar to those obtained with Monte Carlo technique. In addition, a brief discussion about the extension of the method to muti-degree-of-freedom systems is presented.

  10. The Process, Methods and Technics in Compiling Dialect Maps: The Case of Dutch Dialect Atlases / Ağız Atlaslarının Hazırlanışında Süreç, Yöntem ve Teknikler: Flaman Ağız Atlasları Örneği

    Directory of Open Access Journals (Sweden)

    Nihal Çalışkan

    2013-09-01

    Full Text Available Dialect maps show the geographical distribution of linguistic variables. First atlases on European languages were published at the beginning of the 19th century. Since then, many atlases have been revealed at both national and regional level. Contemporarily the so called new age atlases are being compiled in parallel with the advances in digital sciences. In spite of this progress in dialect mapping, the Dialect Atlas of Turkish has not been compiled yet. This study aims to introduce one of the new-age atlas projects, Dutch Dialect Atlases, and particularly deals with the process and methods of the Syntactic Atlas of Dutch Dialects to guide the scholars who will undertake the future Dialect Atlas of Turkish. Ağız atlasları, dilde varyasyonu çeşitli dilbilimsel değişkenlerin coğrafi dağılımına göre gösteren haritalardır. İlk atlaslar Batı dillerinden hareketle 19. yüzyılın başlarında ortaya konmuştur. O tarihten bugüne kadar gerek geniş bölge gerekse dar bölge atlası olarak nitelendirebileceğimiz pek çok atlas hazırlanmış; günümüzde ise özellikle dijital ortamda kaydedilen gelişmelere paralel olarak elektronik erişime ve sorgulamaya uygun yeni nesil atlaslar ortaya çıkmıştır. Ağız atlasları alanındaki bütün bu gelişmelere rağmen Türkiye Türkçesinin ağız atlası henüz hazırlanabilmiş değildir. Bu çalışmada Türkiye Türkçesi için yapılacak ağız atlası çalışmalarında yararlanılabilmesi amacıyla, yeni nesil olarak nitelendirilebilecek atlas projelerinden Flaman ağız atlasları üzerinde durulacak, bunlardan söz dizimini esas alan atlasın hazırlanışındaki süreç, yöntem ve teknikler ele alınacaktır.

  11. Haz eso, haz aquello, mas yo estoy cayendo...: comprendiendo la enfermedad de Chron

    OpenAIRE

    2007-01-01

    Buscando compreender o significado e o impacto da doença de Chron na vida de seu portador, desenvolvemos este estudo, de natureza qualitativa, optando pela História Oral de Vida como referencial metodológico, tendo como base filosófica a corrente monista, advinda de Hipócrates, em que a prática médica tem por objeto a pessoa doente em sua totalidade, levando em conta seu temperamento e a sua história. A terapêutica deve restabelecer a harmonia da pessoa com seu ambiente e consigo mesma , trat...

  12. Investigation on Behavior of Rare Earth Element Cerium in Aluminum-Lithium Alloys by Internal Friction Method

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The behavior of rare earth element Ce in 2090 Al-Li alloys was studied by the method of low frequency internal friction.The results showed that rare earth element Ce can increase the activation energy of grain boundary and improve the grain boundary strength of alloys.Rare earth element Ce can decrease the tendency of softening of elastic modulus of 2090 Al-Li alloys after heat cycle and keep high elastic modulus of initial state.

  13. Prediction on the softening point of bitumen in producing by using SVR%沥青生产过程中软化点的SVR预测

    Institute of Scientific and Technical Information of China (English)

    蔡从中; 王桂莲; 裴军芳; 朱星键

    2011-01-01

    According to an experimental dataset on the softening points of 30 bitumen samples under different resistances and temperatures,the support vector regression(SVR) approach combined with particle swarm optimization(PSO) for its parameter optimization is proposed to conduct leave-one-out cross validation(LOOCV) for modeling and predicting the softening point of bitumen,and its prediction result is compared with that of multivariate linear regression(MLR).The maximum error 2.1 ℃ predicted by SVR is much less than 7.9 ℃ which is calculated by MLR modeling.The statistical results reveal that the root mean square error(RMSE=0.75 ℃),mean absolute error(MAE=0.32 ℃) and mean absolute percentage error(MAPE=0.28%) achieved by SVR-LOOCV are all less than those(RMSE=3.3 ℃,MAE=2.6 ℃ and MAPE=2.34%) calculated via MLR model.This study suggests that the softening point of bitumen can be forecasted timely by SVR to provide an accurate guidance for producing of high-quality bitumen.%根据30组不同电阻和温度下的沥青软化点的实测数据集,应用基于粒子群算法(PSO)寻优的支持向量回归(SVR)方法,并结合留一交叉验证(LOOCV)法对沥青软化点进行了建模和预测研究,将其预测结果与多元线性回归(MLR)模型的计算结果进行了比较。SVR-LOOCV预测的最大误差为2.1℃,远比MLR模型计算的最大误差7.9℃要小得多。统计结果表明:基于SVR-LOOCV预测结果的均方根误差(RMSE=0.75℃)、平均绝对误差(MAE=0.32℃)和平均绝对百分误差(MAPE=0.28%)相应也比MLR回归模型的预测结果(RMSE=3.3℃,MAE=2.6℃和MAPE=2.34%)要小。因此,应用SVR实时预测沥青产品的软化点,可为生产优质沥青提供准确的科学指导。

  14. Research on Softening Model of Soft Clay under Wave Load%波浪荷载作用下软黏土软化模型研究

    Institute of Scientific and Technical Information of China (English)

    付培帅; 唐小微; 韩小凯; 刘功勋

    2015-01-01

    波浪荷载能引起海床土体的主应力轴连续旋转。不同于地震、交通等循环荷载,在周期性波浪荷载作用的土体应力路径方式下,软黏土的软化效用更为明显。本文分别对天然和扰动的海床土体在波浪荷载作用下的应力响应进行模拟,并分析应力路径的特点;为描述软化后的应力-应变关系,将软化效用和累积塑性应变的参数引入到能够反应土体动力非线性的 Hardin-Drnevich 模型中,建立修正模型,使之能够反应软黏土体软化与塑性应变累计特性;通过与模拟波浪荷载下土体应力特征的循环耦合试验结果进行对比分析,验证该修正模型的可靠性。%Wave load causes continuous rotation of the principal stress axes of seabed soil.Unlike seismic load and traffic load,under the action of cyclical wave load,stiffness softening of soft clay is much more obvious.Numerical simulation is applied to obtain the stress response of undis-turbed and disturbed seabed soil,and to analyze the characteristics of the stress path.Under wave loads,the main feature of the seabed soil is the continuous rotation of its maximum principal stress axis;the maximum principal stress’cycle is similar to the wave load cycles.Under the in-fluence of the structure in the seabed disturbance,the soil’s stress path changed under the wave load,and the factors that affect the stress path can be generalized using the initial principal stress orientation,the initial stress ratio,the angle of the major principal stress direction,and other fac-tors.To describe the relation of a soil’s stress and strain after stiffness softening,two parameters were introduced to the Haridin-Drnevich model to reflect the stiffness softening and cumulative plastic strain phenomenon,and these two parameters are a function of the soil’s initial status, which influences its stress path under wave load.The cyclic coupling shear tests can probably sim-ulate the

  15. Optimización del recorrido y de la potencia de un haz láser de CO2 en el tratamiento térmico de válvulas de motores diesel

    Directory of Open Access Journals (Sweden)

    Tobar, M. J.

    2005-12-01

    álvula. La resolución de la ecuación de conducción del calor se presenta complicada, en el momento en el que se incluyen propiedades termofísicas dependientes de la temperatura y una descripción realista de la geometría de la pieza. En la modelización es necesario utilizar métodos numéricos y se ha escogido, en este caso, el Método de los Elementos Finitos en el marco del programa comercial ANSYS®. La aplicación del estudio paramétrico, tanto numérico como experimental, previamente realizado sobre probetas planas a geometrías más complejas, requiere de un ajuste fino de esos parámetros para conseguir resultados comparables y tratamientos equivalentes. Entre otros aspectos del problema cabe resaltar la necesidad de obtener un mapa de isotermas paralelo a la superficie tratada; además la naturaleza circular de la trayectoria que recorre por completo el asiento de la válvula hace que el haz láser, hacia el final de su trayectoria, vuelva sobre el punto inicial, pasando por puntos que ya han sido calentados en el arranque del proceso, por lo tanto el suministro de potencia sobre la pieza ha de adaptarse a estas nuevas condiciones. Evidentemente, es necesario realizar la simulación de la transición de fase, lo que se consigue con las propiedades termofísicas adecuadas y una correcta estimación del coeficiente de absorción en cada una de las fases. Este trabajo muestra las ventajas del modelado teórico como apoyo para la optimización del tratamiento térmico superficial por láser de piezas de geometría compleja partiendo de validaciones realizadas en piezas más sencillas.

  16. Influence of the solution temperature on the corrosion behavior of an austenitic stainless steel in phosphoric acid medium

    Energy Technology Data Exchange (ETDEWEB)

    Ibanez-Ferrandiz, M.V.; Blasco-Tamarit, E.; Garcia-Garcia, D.M.; Garcia-Anton, J. [Valencia Univ. Politecnica, Dept. de Ingenieria Quimica y Nuclear. ETSI Industriales, Valencia (Spain); Guenbour, A.; Bakour, S.; Benckokroun, A. [University Mohammed V-Agdal, Lab. Corrosion-Electrochimie, Faculty of Sciences, Rabat (Morocco)

    2009-07-01

    The objective of the present work is to study the effect of the solution temperature on the corrosion resistance of a highly alloyed austenitic stainless steel (UNS N08031) used as base metal, the welded metal obtained by TIG (Tungsten Inert Gas) welding using a Nickel-base alloy (UNS N06059) as filler metal, and the Heat Affected Zone (HAZ) of the base metal. The materials were tested in 5.5 M phosphoric acid solution at 25 C, 40 C, 60 C and 80 C. Open Circuit Potential tests and potentiodynamic anodic polarization curves have been carried out to obtain information about the electrochemical behavior of the materials. Corrosion potentials and corrosion current densities were obtained from Tafel analysis. The critic potentials and passivation current densities of the studied materials were also analyzed. The galvanic corrosion generated by the electrical contact between the welded metal, the base metal and the HAZ, was estimated from the polarisation diagrams according to the Mixed Potential Theory. The samples were etched to study their microstructure by Optical Microscopy. Results demonstrated that the corrosion potential values shift to more anodic potentials as temperature increases. The corrosion current densities and the passive current densities increased with temperature. Open circuit potential values were located in the passive zone of the potentiodynamic curves, which means that the materials passivated spontaneously. (authors)

  17. Creep rupture behavior of 9Cr–1.8W–0.5Mo–VNb (ASME grade 92) ferritic steel weld joint

    Energy Technology Data Exchange (ETDEWEB)

    Sakthivel, T., E-mail: tsakthivel@igcar.gov.in; Vasudevan, M.; Laha, K., E-mail: laha@igcar.gov.in; Parameswaran, P.; Chandravathi, K.S.; Panneer Selvi, S.; Maduraimuthu, V.; Mathew, M.D.

    2014-01-03

    Creep rupture behavior of 9Cr–1.8W–0.5Mo–VNb (ASME grade 92) ferritic steel weld joint fabricated by activated TIG (A-TIG) welding process have been investigated at 923 K over a stress range of 80–150 MPa. The weld joint was comprise of fusion zone, heat affected zone (HAZ) and base metal. The HAZ consisted of coarse prior-austenite grain (CGHAZ), fine prior-austenite grain (FGHAZ) and intercritical (ICHAZ) regions in an order away from the fusion zone to base metal. A hardness trough was observed at the outer edge of HAZ of the weld joint. TEM investigation revealed the presence of coarse M{sub 23}C{sub 6} precipitates and recovery of martensite lath structure into subgrain in the ICHAZ of the weld joint, leading to the hardness trough. The weld joint exhibited lower creep rupture lives than the base metal at relatively lower stresses. Creep rupture failure location of the weld joint was found to shift with applied stress. At high stresses fracture occurred in the base metal, whereas failure location shifted to FGHAZ at lower stresses with significant decrease in rupture ductility. SEM investigation of the creep ruptured specimens revealed precipitation of Laves phase across the joint, more extensively in the FGHAZ. On creep exposure, the hardness trough was found to shift from the ICHAZ to FGHAZ. Extensive creep cavitation was observed in the FGHAZ and was accompanied with the Laves phase, leading to the premature type IV failure of the steel weld joint at the FGHAZ.

  18. MICROSTRUCTURE AND IMPACT FRACTURE BEHAVIOUR OF HAZ OF F460 HEAVY SHIP PLATE WITH HIGH STRENGTH AND TOUGHNESS%F460高强韧厚船板焊接热影响区的组织和冲击断裂行为

    Institute of Scientific and Technical Information of China (English)

    刘东升; 程丙贵; 罗咪

    2011-01-01

    Thermal cycles of the heat-affected zone (HAZ) of an advanced F460 steel plate used as offshore structure and ship-building in the future were simulated by employing a Gleeble 3800 ther-momechanical simulator. The microstructures of the HAZ formed at different heat input energies (E) were characterized by means of OM, SEM, EBSD and TEM, and mechanical properties were measured. When E is equal to 15 kJ/cm, the microstructures consist of mainly lath-like martensite (LM) with high density dislocations and large misorientations, between the laths exist fine martensite/austenite (M/A) constituents. When E is equal to 30 kJ/cm, lath-like bainite (LB) is formed. The lath grains and M/A constituents will coarsen and the amount of high angle (≥15°) boundaries will decrease with the increase of E to 50 kJ/cm. When E is in a range of 100-300 kJ/cm, the microstructures consist of granular bainite (GB)+upper bainite (UB)+quasi-polygonal ferrite (QPF). The hardness of the HAZ (HV), the maximum Charpy V notch (CVN) impact load (Pm), the brittle fracture arrested load (Pa), the crack propagation rate, and the entire displacement (d0) of the CVN impact course decrease with the increase of E. The size of cleavage facets increases with the increase of E, which can be used to explain the effective grain size of the HAZ increases with the increase of E, as a result, the hardness decreases and low temperature toughness deteriorates as E increases. The upper limit of the simulated heat input E for the F460 steel is 30 kJ/cm which makes the toughness of the HAZ equivalent to that of the mother plate at -60 ℃.%使用Gleeble-3800热模拟试验机模拟单道次焊接条件下大厚度(50 mm)F460钢板热影响区(HAZ)热循环过程,通过OM,SEM,EBSD和TEM研究了HAZ的显微组织随热输入(E)的演化规律.测试了不同E下HAZ的室温硬度(HV),在-40和-60℃下进行了Charpy冲击示波实验(CVN).当E=15 kJ/cm时,显微组织为高位错密度板条马氏体(LM),板条

  19. A model based on the Fermi-Dirac distribution to determine the dose profile of a photon beam; Un modelo basado en la distribucion de Fermi-Dirac para determinar el perfil de dosis de un haz de fotones

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero, R.; Silva, P.; Gutt, F.; Diaz, J. [Instituto Venezolano de Investigaciones Cientificas (IVIC), Laboratorio Secundario de Calibracion Dosimetrica (LSCD), Apartado 21827, Caracas 1020 A (Venezuela)

    1998-12-31

    The objective of this work is to propose a new model based in the Fermi-Dirac distribution, in which it is considered that the photon beams possess a particles behavior when they interact with the matter. (Author)

  20. Solution of Strain-Softening Surrounding Rock in Deep Tunnel Incorporating 3D Hoek-Brown Failure Criterion and Flow Rule

    Directory of Open Access Journals (Sweden)

    Jin-feng Zou

    2016-01-01

    Full Text Available In order to investigate the influence of the intermediate principal stress on the stress and displacement of surrounding rock, a novel approach based on 3D Hoek-Brown (H-B failure criterion was proposed. Taking the strain-softening characteristic of rock mass into account, the potential plastic zone is subdivided into a finite number of concentric annulus and a numerical procedure for calculating the stress and displacement of each annulus was presented. Strains were obtained based on the nonassociated and associated flow rule and 3D plastic potential function. Stresses were achieved by the stress equilibrium equation and generalized Hoek-Brown failure criterion. Using the proposed approach, we can get the solutions of the stress and displacement of the surrounding rock considering the intermediate principal stress. Moreover, the proposed approach was validated with the published results. Compared with the results based on generalized Hoek-Brown failure criterion, it is shown that the plastic radius calculated by 3D Hoek-Brown failure criterion is smaller than those solved by generalized H-B failure criterion, and the influences of dilatancy effect on the results based on the generalized H-B failure criterion are greater than those based on 3D H-B failure criterion. The displacements considering the nonassociated flow rule are smaller than those considering associated flow rules.

  1. Characterizing and Exploring the Formation Mechanism of Salt Deposition by Reusing Advanced-softened, Silica-rich, Oilfield-produced Water (ASOW) in Superheated Steam Pipeline

    Science.gov (United States)

    Dong, Bin; Xu, Ying; Lin, Senmin; Dai, Xiaohu

    2015-11-01

    To dispose of large volumes of oilfield-produced water, an environmentally friendly method that reuses advanced-softened, silica-rich, oilfield-produced water (ASOW) as feedwater was implemented via a 10-month pilot-scale test in oilfield. However, salt deposition detrimental to the efficiency and security of steam injection system was generated in superheated steam pipeline. To evaluate the method, the characteristics and formation mechanism of the deposition were explored. The silicon content and total hardness of the ASOW were 272.20 mg/L and 0.018 mg/L, respectively. Morphology and composition of the deposition were determined by scanning electron microscope-energy dispersive spectrometry (SEM-EDS), inductively coupled plasma-mass spectroscopy (ICP-MS), X-ray diffraction (XRD), laser Raman spectroscopy (LRS) and X-ray photoelectron spectroscopy (XPS). Na2Si2O5, Na2CO3 and trace silanes were identified in the deposition. In addition, the solubility of the deposition was about 99%, suggesting that it is very different from traditional scaling. The results of a simulation experiment and thermal analysis system (TGA and TG-FTIR) proved that Na2CO3 and Si(OH)4 (gas) are involved in the formation of Na2Si2O5, which is ascribed mainly to the temperature difference between the superheated steam and the pipe wall. These findings provide an important reference for improving the reuse of ASOW and reducing its deposition.

  2. Softening of infrared-active mode of perovskite BaZrO{sub 3} proved by terahertz time-domain spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Helal, M. A.; Mori, T.; Kojima, S. [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan)

    2015-05-04

    The low-frequency infrared-active optical modes were studied in a barium zirconate, BaZrO{sub 3}, single crystal with the perovskite structure using terahertz (THz) time-domain spectroscopy (TDS). The real and imaginary parts of the dielectric constants were accurately determined in the frequency range between 0.2 and 2.7 THz. Upon cooling from room temperature to 8 K, the lowest-frequency TO1 mode at 2.32 THz showed a pronounced softening to 1.94 THz. The real part of the dielectric constant at 0.5 THz determined by THz-TDS obeys Barrett's relation, and the existence of a plateau confirms that the quantum effects lead to saturation of the soft mode frequencies of the TO1 and TO2 modes below ≈20 K. This is reminiscent of incipient ferroelectrics with the perovskite structure such as CaTiO{sub 3}.

  3. Density anomaly of charged hard spheres of different diameters in a mixture with core-softened model solvent. Monte Carlo simulation results

    Directory of Open Access Journals (Sweden)

    B. Hribar-Lee

    2013-01-01

    Full Text Available Very recently the effect of equisized charged hard sphere solutes in a mixture with core-softened fluid model on the structural and thermodynamic anomalies of the system has been explored in detail by using Monte Carlo simulations and integral equations theory (J. Chem. Phys., Vol. 137, 244502 (2012. Our objective of the present short work is to complement this study by considering univalent ions of unequal diameters in a mixture with the same soft-core fluid model. Specifically, we are interested in the analysis of changes of the temperature of maximum density (TMD lines with ion concentration for three model salt solutes, namely sodium chloride, potassium chloride and rubidium chloride models. We resort to Monte Carlo simulations for this purpose. Our discussion also involves the dependences of the pair contribution to excess entropy and of constant volume heat capacity on the temperature of maximum density line. Some examples of the microscopic structure of mixtures in question in terms of pair distributions functions are given in addition.

  4. Reaction dynamics. Extremely short-lived reaction resonances in Cl + HD (v = 1) → DCl + H due to chemical bond softening.

    Science.gov (United States)

    Yang, Tiangang; Chen, Jun; Huang, Long; Wang, Tao; Xiao, Chunlei; Sun, Zhigang; Dai, Dongxu; Yang, Xueming; Zhang, Dong H

    2015-01-02

    The Cl + H2 reaction is an important benchmark system in the study of chemical reaction dynamics that has always appeared to proceed via a direct abstraction mechanism, with no clear signature of reaction resonances. Here we report a high-resolution crossed-molecular beam study on the Cl + HD (v = 1, j = 0) → DCl + H reaction (where v is the vibrational quantum number and j is the rotational quantum number). Very few forward scattered products were observed. However, two distinctive peaks at collision energies of 2.4 and 4.3 kilocalories per mole for the DCl (v' = 1) product were detected in the backward scattering direction. Detailed quantum dynamics calculations on a highly accurate potential energy surface suggested that these features originate from two very short-lived dynamical resonances trapped in the peculiar H-DCl (v' = 2) vibrational adiabatic potential wells that result from chemical bond softening. We anticipate that dynamical resonances trapped in such wells exist in many reactions involving vibrationally excited molecules.

  5. X-ray softening in the new X-ray transient XTE J1719-291 during its 2008 outburst decay

    CERN Document Server

    Padilla, M Armas; Patruno, A; Russell, D M; Linares, M; Maccarone, T J; Homan, J; Wijnands, R

    2011-01-01

    The X-ray transient XTE J1719-291 was discovered with RXTE/PCA during its outburst in 2008 March, which lasted at least 46 days. Its 2-10 keV peak luminosity is 7E35 erg/s assuming a distance of 8 kpc, which classifies the system as a very faint X-ray transient. The outburst was monitored with Swift, RXTE, Chandra and XMM-Newton. We analysed the X-ray spectral evolution during the outburst. We fitted the overall data with a simple power-law model corrected for absorption and found that the spectral index increased with decreasing luminosity. However, the XMM-Newton spectrum can not be fitted with a simple one-component model, but it can be fitted with a thermal component (black body or disc black body) plus power-law model affected by absorption. Therefore, the softening of the X-ray spectrum with decreasing X-ray luminosity might be due to a change in photon index or alternatively it might be due to a change in the properties of the soft component. Assuming that the system is an X-ray binary, we estimated a ...

  6. Sex difference and menstrual cycle effects on semantic priming and rememberingAnlamsal hazırlama ve hatırlamada cinsiyet farkı ve menstural dönem etkileri

    Directory of Open Access Journals (Sweden)

    Evrim Gülbetekin

    2015-02-01

    fluctuate across the menstrual cycle. The findings were discussed in the context of the negative effects of increasing luteinizing hormone (LH levels on attentional and executive functions in both ovulatory phase and Alzheimer’s disease. ÖzetAmaç: Kadınların ve erkeklerin bazı bilişsel işlemlerde ve hemisferik özelleşmelerde farklılık gösterdiği; buna karşın, cinsiyet farklılıklarına ilişkin çalışmaların her zaman çok tutarlı olmadığı bilinmektedir. Son dönemlerde yapılan çalışmalar, kadınlardaki bilişsel becerilerin menstural döneme bağlı olarak dalgalanma gösterebildiğine işaret etmiştir. Sunulan çalışmada erkeklerin ve farklı menstural dönemdeki kadınların (yumurtlama ve mensturasyon anlamsal hazırlama (AH ve hatırlama görevindeki peformansları yönünden farklılık gösterip göstermediğini incelemek amaçlanmıştır. Ayrıca AH görevinde cinsiyete özgü hemisferik özelleşme olup olmadığı incelenmiştir.Yöntem: Çalışmaya 72 kadın ve 29 erkek üniversite öğrencisi katılmıştır. AH görevi için katılımcılara arka arkaya iki resim gösterilmiştir. Görsel-yarı alan tekniği kullanılarak ve deney gruplarına uygun olarak ilk resim sol görsel alanda, sağ görsel alanda ya da merkezde100ms sunulmuş; katılımcılardan merkezde sunulan birinci resimle ikinci resmin ilişkili olup olmadığını belirtmeleri istenmiştir. AH görevinin ardından katılımcılara deneydeki uyarıcıların bir listesi verilmiş ve bunun içinden hatırladıklarını bir dakikalık sürede işartlemeleri istenmiştir.Bulgular: Tüm gruplarda AH etkisinin olduğu; ancak bu göreve ilişkin bir hemisferik özelleşmenin olmadığı bulunmuştur. Erkekler ilişkili resimleri yumurtlama dönemindeki kadınlardan daha hızlı değerlendirirken, mensturasyon dönemindeki kadınlarla böyle bir farklılık gözlenmemiştir. Benzer şekilde erkeklerin hatırladıkları genel uyarıcı ve ilişkisiz uyarıcı say

  7. Study of Pitting Corrosion Behavior of FSW weldments of AA6101- T6 Aluminium Alloy

    Directory of Open Access Journals (Sweden)

    L.V. Kamble

    2015-09-01

    Full Text Available Friction Stir Welding (FSW is a promising solid state joining process widely used generally for Al alloys, especially in aerospace, marine and automobile applications. In present work, the microstructure and corrosion behavior of friction stir welded AA6101 T6 Al alloy is studied. The friction stir welding was carried using vertical milling machine with different tool rotational speeds and welding speeds. The microstructure at weld nugget or stir zone (SN, thermo-mechanically affected zone (TMAZ, heat affected zone (HAZ and base metal were observed using optical microscopy. The corrosion tests of base alloy and welded joints were carried out in 3.5% NaCl solution at temperature of 30º C. Corrosion rate and emf were determined using cyclic polarization measurement.

  8. MECHANICAL BEHAVIOR OF AMORPHOUS POLYMERS IN SHEAR

    Institute of Scientific and Technical Information of China (English)

    张赟; 黄筑平

    2004-01-01

    Based on the non-equilibrium thermodynamic theory, a new thermo-viscoelastic constitutive model for an incompressible material is proposed. This model can be considered as a kind of generalization of the non-Gaussian network theory in rubber elasticity to include the viscous and the thermal effects. A set of second rank tensorial internal variables was introduced, and in order to adequately describe the evolution of these internal variables, a new expression of the Helmholtz free energy was suggested. The mechanical behavior of the thermo-viscoelastic material under simple shear deformation was studied, and the "viscous dissipation induced" anisotropy due to the change of orientation distribution of molecular chains was examined. Influences of strain rate and thermal softening produced by the viscous dissipation on the shear stress were also discussed. Finally, the model predictions were compared with the experimental results performed by G'Sell et al., thus the validity of the proposed model is verified.

  9. Structural modifications and phonon softening in Bi sub 2 Sr sub 2 Ca sub 1 sub - sub x R sub x Cu sub 2 O sub 8 sub + subdelta (R = Pr and Gd) single crystals

    CERN Document Server

    Feng, S J; Han, Q; Ma, J; Shi, L; Sun, X F; Zuo, J; Li, X G

    2003-01-01

    The phonon Raman spectra of Bi sub 2 Sr sub 2 Ca sub 1 sub - sub x R sub x Cu sub 2 O sub 8 sub + subdelta (R = Pr and Gd) single crystals are systematically investigated. The experimental results show that the O(2) sub S sub r A sub 1 sub g mode softens with Pr and Gd doping, while the O(1) sub C sub u B sub 1 sub g mode softens with Pr doping but hardens with Gd doping. The changes of average ionic radius on the Ca site in Bi-based cuprates can account well for the Raman frequency shifts of the O(1) sub C sub u mode, but have little influence on the O(2) sub S sub r mode. The frequency softening of the O(2) sub S sub r mode in Pr-and Gd-doped Bi2212 crystals mainly results from contraction of the BiO bilayers with doping content. The correlation between the O(2) sub S sub r mode frequency and the c-axis parameter as well as the incommensurate modulation wavelength is discussed.

  10. Fatigue Hardening Behavior of 1.5 GPa Grade Transformation-Induced Plasticity-Aided Martensitic Steel

    Science.gov (United States)

    Sugimoto, Koh-Ichi; Hojo, Tomohiko

    2016-11-01

    Low cycle fatigue hardening/softening behavior of a 0.2 pct C-1.5 pct Si-1.5 pct Mn-1.0 pct Cr-0.2 pct Mo-0.05 pct Nb transformation-induced plasticity (TRIP)-aided steel consisting of a wide lath martensite structure matrix and a narrow lath martensite-metastable retained austenite mixture was investigated. The steel exhibited notable fatigue hardening in the same way as TRIP-aided bainitic ferrite steel, although conventional martensitic steel such as SCM420 steel with the same tensile strength exhibited fatigue softening. The considerable fatigue hardening of this steel is believed to be associated mainly with the compressive internal stress that results from a difference in flow stress between the matrix and the martensite-austenite-like phase, with a small contribution from the strain-induced transformation and dislocation hardenings.

  11. Correlation between the Cyclic Stress Behavior and Microstructure in 316LN based on the Analysis of Hysteresis Loops

    Institute of Scientific and Technical Information of China (English)

    CHANG Bo; ZHANG Zheng

    2014-01-01

    Total strain controlled cyclic test was performed on 316LN under uniaxial loadings. Through the partitioning of hysteresis loops, the evolution of two components of cyclic flow stress, the internal and effective stresses, was reported. The former one determines the cyclic stress response. Based on the transmission electron microscopic (TEM) observation on specimens loaded with scheduled cycles, it is found that planar dislocation structures prevail during the entire cyclic process at low strain amplitude, while a remarkable dislocation rearrangement from planar structures to heterogeneous spatial distributions is companied by a cyclic softening behavior at high strain amplitude. The competition between the evolution of the intergranular and the intragranular components of the internal stress caused by the transition of slip mode induces the cyclic hardening and softening at high strain levels. The intergranular internal stress represents the most part of the internal stress at low strain level.

  12. Effect of deformation temperature on the hot compressive behavior of metal matrix composites with misaligned whiskers

    Institute of Scientific and Technical Information of China (English)

    LI Aibin; MENG Qingyuan; GENG Lin; DENG Chunfeng; YAN Yiwu

    2007-01-01

    A multi-inclusion cell model is used to investigate the effect of deformation temperature and whisker rotation on the hot compressive behavior of metal matrix composites with misaligned whiskers. Numerical results show that deformation temperature influences the work-hardening behavior of the matrix and the rotation behavior of the whiskers. With increasing temperature, the work hardening rate of the matrix decreases, but the whisker rotation angle increases. Both whisker rotation and the increase of deformation temperature can induce reductions in the load supported by whisker and the load transferred from matrix to whisker. Additionally, it is found that during large strain deformation at higher temperatures, the enhancing of deformation temperature can reduce the effect of whisker rotation. Meanwhile, the stress-strain behavior of the composite is rather sensitive to deformation temperature. At a relatively lower temperature (150℃), the composite exhibits work hardening due to the matrix work hardening, but at relatively higher temperatures (300℃ and above),the composite shows strain softening due to whisker rotation. It is also found that during hot compression at higher temperatures, the softening rate of the composite decreases with increasing temperature. The predicted stress-strain behavior of the composite is approximately in agreement with the experimental results.

  13. Insights into transcriptional regulation of β-D-N-acetylhexosaminidase, an N-glycan-processing enzyme involved in ripening-associated fruit softening.

    Science.gov (United States)

    Irfan, Mohammad; Ghosh, Sumit; Kumar, Vinay; Chakraborty, Niranjan; Chakraborty, Subhra; Datta, Asis

    2014-11-01

    Tomato (Solanum lycopersicum) fruit ripening-specific N-glycan processing enzyme, β-D-N-acetylhexosaminidase (β-Hex), plays an important role in the ripening-associated fruit-softening process. However, the regulation of fruit ripening-specific expression of β-Hex is not well understood. We have identified and functionally characterized the fruit ripening-specific promoter of β-Hex and provided insights into its transcriptional regulation during fruit ripening. Our results demonstrate that RIPENING INHIBITOR (RIN), a global fruit ripening regulator, and ABSCISIC ACID STRESS RIPENING 1 (SlASR1), a poorly characterized ripening-related protein, are the transcriptional regulators of β-Hex. Both RIN and SlASR1 directly bound to the β-Hex promoter fragments containing CArG and C₂₋₃(C/G)A cis-acting elements, the binding sites for RIN and SlASR1, respectively. Moreover, β-Hex expression/promoter activity in tomato fruits was downregulated once expression of either RIN or SlASR1 was suppressed; indicating that RIN and SlASR1 positively regulate the transcription of β-Hex during fruit ripening. Interestingly, RIN could also bind to the SlASR1 promoter, which contains several CArG cis-acting elements, and SlASR1 expression was suppressed in rin mutant fruits, indicating that RIN also acts as a positive regulator of SlASR1 expression during fruit ripening. Taken together, these results suggest that RIN, both directly and indirectly, through SlASR1, regulates the transcription of β-Hex during fruit ripening. The fruit ripening-specific promoter of β-Hex could be a useful tool in regulating gene expression during fruit ripening.

  14. Structural and magnetic properties of Ni78Fe22 thin films sandwiched between low-softening-point glasses and application in spin devices

    Science.gov (United States)

    Misawa, Takahiro; Mori, Sumito; Komine, Takashi; Fujioka, Masaya; Nishii, Junji; Kaiju, Hideo

    2016-12-01

    We investigate the structural and magnetic properties of Ni78Fe22 thin films sandwiched between low-softening-point (LSP) glasses, which can be used in spin quantum cross (SQC) devices utilizing stray magnetic fields generated from magnetic thin-film edges. We also calculate the stray magnetic field generated between the two edges of Ni78Fe22 thin-film electrodes in SQC devices and discuss the applicability to spin-filter devices. Using the established fabrication technique, we successfully demonstrate the formation of LSP-glass/Ni78Fe22/LSP-glass structures with smooth and clear interfaces. The coercivity of the Ni78Fe22 thin films is enhanced from 0.9 to 103 Oe by increasing the applied pressure from 0 to 1.0 MPa in the thermal pressing process. According to the random anisotropy model, the enhancement of the coercivity is attributed to the increase in the crystal grain size. The stray magnetic field is also uniformly generated from the Ni78Fe22 thin-film edge in the direction perpendicular to the cross section of the LSP-glass/Ni78Fe22/LSP-glass structures. Theoretical calculation reveals that a high stray field of approximately 5 kOe is generated when the distance between two edges of the Ni78Fe22 thin-film electrodes is less than 5 nm and the thickness of Ni78Fe22 is greater than 20 nm. These experimental and calculation results indicate that Ni78Fe22 thin films sandwiched between LSP glasses are useful as electrodes for SQC devices, serving as spin-filter devices.

  15. Foliation development and reaction softening by dissolution and precipitation in the transformation of granodiorite to orthogneiss, Glastonbury Complex, Connecticut, U.S.A

    Science.gov (United States)

    Wintsch, R.P.; Aleinikoff, J.N.; Yi, K.

    2005-01-01

    Textures, microstructures, and patterns of chemical zoning in minerals in a granodioritic orthogneiss in the Glastonbury Complex, Connecticut, lead to the interpretation that foliation development was facilitated by retrograde hydration reactions in the presence of an aqueous fluid. Incomplete replacement of the metastable magmatic minerals K-feldspar + hastingsite + magnetite produced foliation-defining biotite + epidote + quartz. These reaction products did not replace K-feldspar - hastingsite interfaces; rather, either biotite or epidote replaced the amphibole, and plagioclase replaced K-feldspar. Biotite and epidote precipitated syntectonically in discrete layers that define the foliation in the orthogneiss, whereas quartz precipitated primarily in ribbons, further enhancing the fabric. Metastable REE-rich igneous titanite also dissolved, and was incompletely replaced by REE-poor, Al-bearing metamorphic titanite. The similar concentrations of the REE in epidote and titanite show that the REE released by titanite dissolution were precipitated locally as the allanite component in adjacent grains of epidote. The entire process was syntectonic, with most grains showing multiple overgrowths in the direction of extension as defined by stretched xenoliths. Sufficient U was present in the titanite overgrowths to allow SHRIMP dating of cores, mantles, and rims. These results suggest at least three retrograde Alleghanian events of growth in a span of ???30 m.y. Thus the dissolution - transportation - precipitation process not only describes the reaction mechanism but also leads to the redistribution of reaction products into nearly monomineralic layers, thus contributing to metamorphic differentiation and to the development of the foliation. The resulting orthogneiss was much weaker that the granodiorite protolith, owing to this reaction and textural softening.

  16. Expression and location of endo-beta-mannanase during the ripening of tomato fruit, and the relationship between its activity and softening.

    Science.gov (United States)

    Wang, Aoxue; Li, Jingfu; Zhang, Bingxiu; Xu, Xiangyang; Bewley, J Derek

    2009-10-15

    Endo-beta-mannanase is thought to play a role in tomato fruit ripening by participating in the degradation of cell walls. Its spatial and temporal expression during ripening was examined, as was the relationship between its activity and softening of the fruit using a large number of tomato lines, and by suppression of transcription of the endo-beta-mannanase (LeMan4a) gene. Immunolocalization studies showed that the enzyme is expressed in the fruit cell wall at all ripening stages, but it is not active during the initial green stage; this is not due to the presence of inhibitors of its activity, nor due to changes in its mRNA sequence. Transient expression in onion epidermal cells of endo-beta-mannanase transcripts fused to green fluorescent protein resulted in the expressed enzyme being localized to the cell walls. Transgenic tomato plants expressing a GUS gene attached to the LeMan4a promoter showed that this occurs initially during ripening in the skin and outer pericarp of the fruit, and later in the skin and throughout the pericarp. Fruit firmness and activity of endo-beta-mannanase were not strongly correlated during ripening of many lines of tomato. Several plants of cv. Micro-Tom were transformed using RNA interference (mRNAi) and antisense RNA strategies to suppress transcription of the LeMan4a gene. When endo-beta-mannanase activity was much reduced in the transgenic fruits, their firmness was higher compared to those of control fruits at the turning and orange-color stages, but at the red-ripe stage firmness was similar between the two fruit types. We suggest that while the enzyme does participate in fruit ripening it alone is not sufficient to cause hydrolysis of the cell walls which results in their weakening; it likely plays a cooperative role with other known wall-modifying enzymes, and/or is involved in cell wall rearrangement.

  17. FEM modeling of softened base metal in narrow-gap joint by CMT+P MIX welding procedure%冷金属过渡复合脉冲焊接(CMT+P)窄间隙焊接头基体软化现象的有限元模拟

    Institute of Scientific and Technical Information of China (English)

    舒凤远; 吕耀辉; 刘玉欣; 徐富家; 孙哲; 何鹏; 徐滨士

    2014-01-01

    A required finite element method (FEM) model applicable for narrow gap CMT and CMT+P MIX welding was established based on the interactions between arc, base metal and filler metal. A novel method of simplifying wire feeding pulses and heat input pulses was supposed under the conduction of equivalent input. The method together with composed double-ellipse heat sources was included in the model. The model was employed in the investigation of thermal cycling and the identification of the softened zone of AA7A52 base plates. Low-frequency behavior emerged in the form of low-cooling rate sects, which were not expected under experimental conditions. The softened zone including the quenched zone and averaging zone of the base plate was much wider internal the base plate than that close to the surfaces. The reliability of the predictions in thermal cycling was supported by infrared imaging test results of the thermal cycle process.%根据电弧对基体材料及填充材料的作用过程建立了 CMT 和 CMT+P 过程的有限元模型,其中基于等效热输入原则简化了 CMT 焊接过程中焊丝进退和热输入之间的相互作用过程。对热源的处理中,采用复合双椭球热源模型。基于该有限元模型研究了热循环规律,由此划分出AA7A52母材的焊接热影响区。模拟计算结果与实验结果的不同之处是,冷却过程中出现低频效应,这种低频效应的表现方式为低冷却速率。软化区包括淬火区和过时效区,基板内部的软化范围明显大于基板近表层区域。通过红外测温实验验证了计算模拟结果的准确性。

  18. Effect of the welding profile generated by the modified indirect electric arc technique on the fatigue behavior of 6061-T6 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ambriz, R.R., E-mail: ricraf74@gmail.com [Universite Lille Nord de France, F-59000 Lille (France); USTL, LML, F-59650 Villeneuve d' Ascq (France); CNRS, UMR 8107, F-59650 Villeneuve d' Ascq (France); Mesmacque, G. [Universite Lille Nord de France, F-59000 Lille (France); USTL, LML, F-59650 Villeneuve d' Ascq (France); CNRS, UMR 8107, F-59650 Villeneuve d' Ascq (France); Ruiz, A. [Instituto de Investigaciones Metalurgicas, Universidad Michoacana de San Nicolas de Hidalgo, A.P. 888, C.P. 58000, Morelia Michoacan (Mexico); Amrouche, A. [Universite Lille Nord de France, F-59000 Lille (France); USTL, LML, F-59650 Villeneuve d' Ascq (France); CNRS, UMR 8107, F-59650 Villeneuve d' Ascq (France); Lopez, V.H. [Instituto de Investigaciones Metalurgicas, Universidad Michoacana de San Nicolas de Hidalgo, A.P. 888, C.P. 58000, Morelia Michoacan (Mexico)

    2010-03-25

    This paper reports the effect of the welding profile generated by the modified indirect electric arc (MIEA) technique on the fatigue behavior of 6061-T6 welded joints. The calculations are based on the effect of the stress concentration factor produced by the characteristic geometry of the welding profile formed during the welding process. It was found that the fatigue life of welded samples using this welding technique was larger in comparison with data reported in the literature. Also, measurements of microhardness and tension testing were performed to account for the effect of different levels of fatigue damage on the mechanical properties of these welds. Experimental findings reveal that, with reference to undamaged samples, fatigue damage increases the microhardness in the weld metal and heat affected zone (HAZ) whereas it only produces a moderate increase in yield strength of approximately 14% for a 75% of fatigue damage. Tensile and fatigue tests indicate that the thermal affection undergone by the plates during fusion welding dictates failure in the HAZ under tension stress but not under fatigue. The failure mechanism under fatigue is discussed in terms of theoretical analyses and fractography.

  19. Microstructure characteristics and temperature-dependent high cycle fatigue behavior of advanced 9% Cr/CrMoV dissimilarly welded joint

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Qingjun [Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, Shanghai 200240 (China); Lu, Fenggui, E-mail: Lfg119@sjtu.edu.cn [Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, Shanghai 200240 (China); Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai University, Shanghai 200072 (China); Cui, Haichao [Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, Shanghai 200240 (China); Ding, Yuming; Liu, Xia [Shanghai Turbine Plant of Shanghai Electric Power Generation Equipment Co. Ltd., Shanghai 200240 (China); Gao, Yulai, E-mail: ylgao@shu.edu.cn [Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai University, Shanghai 200072 (China)

    2014-10-06

    Advanced 9% Cr and CrMoV steels chosen as candidate materials are first welded by narrow-gap submerged arc welding (NG-SAW) to fabricate the heavy section rotor. The present work focuses on studying the high-cycle fatigue (HCF) behavior of advanced 9% Cr/CrMoV dissimilarly welded joint at different temperatures. Conditional fatigue strength of this dissimilarly welded joint was obtained by HCF tests at room temperature (RT), 400 °C and 470 °C. It was observed that the failure occurred at the side of CrMoV base metal (BM), weld metal (WM) and heat affected zone (HAZ) of CrMoV side over 5×10{sup 7} cycles for the specimens tested at RT, 400 °C and 470 °C. The detailed microstructures of BMs, WMs and HAZs as well as fracture appearance were observed by optical microscopy (OM) and scanning electron microscopy (SEM). Precipitation and aggregation of carbides along the grain boundaries were clearly detected with the increase of temperature, which brought a negative effect on the fatigue properties. It is interesting to note that the inclusion size leading to crack initiation became smaller for the HCF test at higher temperature. Therefore, reduction in the inclusion size in a welded joint helps to improve the HCF performance at high temperature.

  20. An exact solution for the history-dependent material and delamination behavior of laminated plates subjected to cylindrical bending

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Todd O [Los Alamos National Laboratory

    2009-01-01

    The exact solution for the history-dependent behavior of laminated plates subjected to cylindrical bending is presented. The solution represents the extension of Pagano's solution to consider arbitrary types of constitutive behaviors for the individual lamina as well as arbitrary types of cohesive zones models for delamination behavior. Examples of the possible types of material behavior are plasticity, viscoelasticity, viscoplasticity, and damaging. Examples of possible CZMs that can be considered are linear, nonlinear hardening, as well as nonlinear with softening. The resulting solution is intended as a benchmark solution for considering the predictive capabilities of different plate theories. Initial results are presented for several types of history-dependent material behaviors. It is shown that the plate response in the presence of history-dependent behaviors can differ dramatically from the elastic response. These results have strong implications for what constitutes an appropriate plate theory for modeling such behaviors.

  1. Effects of adaptation and preparation studies on abilities of first grade students according to class teachersSınıf öğretmenlerine göre ilkokul birinci sınıf uyum ve hazırlık çalışmalarının öğrencilerin becerilerine etkisi

    Directory of Open Access Journals (Sweden)

    Remzi Kılıç

    2014-11-01

    Full Text Available Aim of the research is to determine the effects of adaptation and preparation studies on abilities of students in Turkish, Math, Social Sciences, Games and Physical Activities, Musical and Visual Arts that is performed by class teachers of first grade students. Sampling of this research that has been designed as to the Scanning Model consists of 27 class teachers who are choosen randomly, and their actual students,789 in total,from the schools of Çekmeköy, Pendik, Kadıköy, Sultanbeyli in İstanbul. In the research, as a data collection device which has been developed by researchers " Student Evaluation Form For First Grade Adaptation and Preparation Studies" and " Student Information Form" is used.In conclusion of the research, according to the evaluation of the class teachers, on the grounds of adaptation and preparation studies, it is clear that ;athey positively affect the ability developments of the students,bthey equally affect the ability developments of both male and female studentscthey are less effective in 60-66 month old students when compared to the other age group of two.dthey are much more effective on the students who get pre-school education. ÖzetBu araştırmanın amacı ilkokul birinci sınıfta görev yapan sınıf öğretmenlerine göre uyum ve hazırlık çalışmalarının öğrencilerin Türkçe, Matematik, Hayat Bilgisi, Oyun ve Fiziki Etkinlikler, Müzik ve Görsel Sanatlar dersleri becerilerine olan etkisini belirlemektir. Tarama modeline göre tasarlanan bu araştırmanın örneklemini İstanbul ili Çekmeköy, Pendik, Kadıköy ve Sultanbeyli ilçelerindeki ilkokullarda görev yapmakta olan ve yansız olarak seçilen 27 birinci sınıf öğretmeni ve bu öğretmenlerin sınıflarında öğrenim gören 789 öğrenci oluşturmaktadır. Araştırmada veri toplama aracı olarak araştırmacılar tarafından geliştirilen “ilkokul birinci sınıf uyum ve hazırlık çalışmaları öğrenci değerlendirme formu

  2. Measurement and analysis of the effect of an uneven surface (STEP) in an electron beam quality control planners; Medida y analisis de efecto de una superficie irregular (ESCALON) en un haz de electrones para control de calidad de planificadores

    Energy Technology Data Exchange (ETDEWEB)

    Angulo Pain, E.; Urena Llinares, A.; Ramos Caballero, L. J.; Quinones Rodriguez, L. A.; Castro Ramirez, I.; Iborro Oquendo, M.

    2011-07-01

    The objective of this study is to analyze the behavior of the algorithm for calculating electron of our scheduler when there is a discontinuity or step in the phantom with respect to the incidence of the beam. It reflects the special situation in some areas of treatment where the irregularity on the surface is very large surface constituting a real step, as for example in areas close to the jaw. Therefore, as stated in the National Protocol for quality control planning systems of radiation therapy in SEFM DOH5 test, we verify the accuracy of the calculation under the conditions described above.

  3. 原状黄土遇水及饱和后软化特征研究%A study of soften characteristics of wet and saturated loess

    Institute of Scientific and Technical Information of China (English)

    董林; 王兰民; 夏坤; 王峻

    2016-01-01

    黄土由于特殊的结构性导致其水敏性,以往相关研究多采用室内试验的方法.文章以动三轴弯曲元试验系统对原状黄土和饱和黄土在各级围压下的剪切波速与轴向变形进行了测试,并对兰州市西固区某饱和黄土场地进行了现场钻孔及原位试验.室内及现场试验结果表明,黄土遇水模量软化,饱和黄土更具有触变性.进一步对比饱和粉土与砂土的剪切波速与标贯击数统计关系,发现饱和粉土由于触变性导致标贯击数较小,而剪切波速为小应变无损测试,最终表现为剪切波速相同的饱和粉土与砂土,粉土标贯击数显著小于砂土.%Structural loess is water sensitivity,and previous studies are almost made by laboratory tests.Using cyclic triaxial apparatus along with the bender element system,shear-wave velocity and axial deformation of undisturbed loess and saturated loess were tested under different confining pressures.Furthermore,a borehole and in-situ tests were carried out at a saturated loess site in the Xigu district near Lanzhou.The laboratory and in-situ test results show that loess will soften during wetting,and saturated loess presents thixotropy.By comparing the statistical relationship between the shear-wave velocity and SPT blow count of saturated silts with that of sands,it is found that SPT blow count for saturated silts are small due to thixotropy,and the shear-wave velocity is a small strain and non-destructive test.For the saturated silt and sand with an identical shear-wave velocity,the SPT blow count of the saturated silt is significantly less than that of sand.

  4. Magnetic Transitions in the Spin-5/2 Frustrated Magnet BiMn2PO6 and Strong Lattice Softening in BiMn2PO6 and BiZn2PO6 Below 200 K

    Energy Technology Data Exchange (ETDEWEB)

    Nath, R [Indian Institute of Science Education and Research; Ranjith, K M [Indian Institute of Science Education and Research; Roy, B [Ames Laboratory; Johnston, D C [Ames Laboratory; Furukawa, Y [Ames Laboratory; Tsirlin, A A [National Institute of Chemical Physics and Biophysics

    2014-07-01

    The crystallographic, magnetic, and thermal properties of polycrystalline BiMn2PO6 and its nonmagnetic analog BiZn2PO6 are investigated by x-ray diffraction, magnetization M, magnetic susceptibility χ, heat capacity Cp, and P31 nuclear magnetic resonance (NMR) measurements versus applied magnetic field H and temperature T as well as by density-functional band theory and molecular-field calculations. Both compounds show a strong monotonic lattice softening on cooling, where the Debye temperature decreases by a factor of two from ΘD~650 K at T=300 K to ΘD~300 K at T=2 K. The χ(T) data for BiMn2PO6 above 150 K follow a Curie-Weiss law with a Curie constant consistent with a Mn+2 spin S=5/2 with g factor g=2 and an antiferromagnetic (AFM) Weiss temperature θCW≃-78 K. The χ data indicate long-range AFM ordering below TN≃30 K, confirmed by a sharp λ-shaped peak in Cp(T) at 28.8 K. The magnetic entropy at 100 K extracted from the Cp(T) data is consistent with spin S=5/2 for the Mn+2 cations. The band-theory calculations indicate that BiMn2PO6 is an AFM compound with dominant interactions J1/kB≃6.7 K and J3/kB≃5.6 K along the legs and rungs of a Mn two-leg spin-ladder, respectively. However, sizable and partially frustrating interladder couplings lead to an anisotropic three-dimensional magnetic behavior with long-range AFM ordering at TN≃30 K observed in the χ, Cp, and NMR measurements. A second magnetic transition at ≈10 K is observed from the χ and NMR measurements but is not evident in the Cp data. The Cp data at low T suggest a significant contribution from AFM spin waves moving in three dimensions and the absence of a spin-wave gap. A detailed analysis of the NMR spectra indicates commensurate magnetic order between 10 and 30 K, while below 10 K additional features appear that may arise from an incommensurate modulation and/or spin canting. The commensurate order is consistent with microscopic density functional calculations that yield a

  5. Dynamic recrystallization behavior of AZ61 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hai-tao; YAN An-qing; LIU Chu-ming

    2005-01-01

    An AZ61 alloy was subjected to hot compression at temperatures ranging from 523 K to 673 K,with strain rates of 0. 001 - 1 s-1. Flow softening occurs at all temperatures and strain rates. There are peak and plateau stresses on flow curves. The initiation and evolution of dynamic recrystallization(DRX) were studied by the flow softening mechanism based on the flow curves and microstructural observations. A linear relationship was established between the logarithmic value of the critical strain for DRX initiation(lnεc) and the logarithmic value of the Zener-Hollomon parameter (lnZ). The volume fraction of DRX grain (ψd) is formulated as a function of the process parameters including strain rate, temperature, and strain. The calculated values of ψd agree well with the values extracted from the flow curves. The size of DRX grain(d) was also formulated as a function of the ZenerHollomon parameter. This study suggests that DRX behavior of AZ61 can be predicated from plastic process parameters.

  6. Dynamic recrystallization behavior and kinetics of high strength steel

    Institute of Scientific and Technical Information of China (English)

    吴光亮; 周超洋; 刘新彬

    2016-01-01

    The dynamic recrystallization behavior of high strength steel during hot deformation was investigated. The hot compression test was conducted in the temperature range of 950−1150 °C under strain rates of 0.1, 1 and 5 s−1. It is observed that dynamic recrystallization (DRX) is the main flow softening mechanism and the flow stress increases with decreasing temperature and increasing strain rate. The relationship between material constants (Q, n, α and lnA) and strain is identified by the sixth order polynomial fit. The constitutive model is developed to predict the flow stress of the material incorporating the strain softening effect and verified. Moreover, the critical characteristics of DRX are extracted from the stress−strain curves under different deformation conditions by linear regression. The dynamic recrystallization volume fraction decreases with increasing strain rate at a constant temperature or decreasing deformation temperature under a constant strain rate. The kinetics of DRX increases with increasing deformation temperature or strain rate.

  7. The Effects of Preservation Methods and Temperature of Softening Specimens on DNA Extraction from Apis mellifera%保存方式和回软温度对蜜蜂标本 DNA 提取的影响

    Institute of Scientific and Technical Information of China (English)

    张红利; 贾鑫磊; 刘建霞; 张永芳

    2016-01-01

    旨在探寻保存方式及制作干标本前回软温度对蜜蜂不同部位 DNA 的影响。采用酚-氯仿法对不同方式保存的蜜蜂以及不同温度回软后的蜜蜂干标本的总 DNA 进行提取,通过琼脂糖凝胶电泳和 PCR 扩增对 DNA 的提取结果进行鉴定。电泳结果显示,从新鲜标本、无水乙醇泡制或自然干燥保存半年的标本中均可提取到较高质量的总 DNA,尤以头部与足部提取效果最佳。经不同水浴温度回软后保存半年的蜜蜂干标本总 DNA 提取结果显示,回软温度为65℃时对蜜蜂 DNA 的破坏性最小,DNA 提取的最佳部位为蜜蜂足部。正交试验结果显示,55℃回软后的足部为蜜蜂干标本 DNA 提取的最优组合。PCR 扩增结果显示,本实验提取的总 DNA 能成功地应用于蜜蜂线粒体基因16S rRNA 和 CO I 的扩增。从保存方式、提取部位和回软操作3个因素对蜜蜂标本DNA 的提取进行了研究,提供了较好的选择方案。%This work aims to explore the effects of preservation methods and temperature while softening specimens before drying the specimen on DNA from different parts of bees. The phenol - chloroform method was used to extract the total DNA from bee specimens preserved in different methods and from those dried bee specimens softened at different temperatures. The extracted DNA was analyzed and identified using agarose gel electrophoresis and the PCR amplification. The electrophoresis images showed that fine-quality DNA was extracted from all specimens,including specimens collected freshly,specimens soaked with alcohol,and specimens dried under natural conditions,and the quality of genomic DNA from the head and the leg of these specimens was better than that from other parts. The total extracted DNA results from dried bees softened under different bath temperatures and preserved half year showed that 65℃ was the optimal softening temperature,and the damages to bee’s DNA

  8. Analysis of Author's Presence Metadiscourse in Dictionary of the K haz ars from the Perspective of Linguistic Adaptation Theory%顺应论视角下作者现身元话语的语用分析--以《哈扎尔辞典》为例

    Institute of Scientific and Technical Information of China (English)

    韩斌

    2015-01-01

    文章在顺应论的框架下分析了《哈扎尔辞典》中作者现身元话语的顺应性特征,发现作者正是通过有意识地动态顺应文本的交际语境与语言结构来实现与读者的交流,并表达出了对读者和文本的态度和观点,从而实现了文本创作的目的。%Within the framework of the Linguistic Adaptation Theory ,this paper analyzes the adapta‐tive features of the author's presence metadiscourse in Dictionary of the K haz ars and finds that the author in the fiction dynamically adapts to the contextual correlates and the structural objects with a relatively high degree of salience in order to interact with readers and express his attitudes toward the readers and the fiction itself ,and finally realizes the communicative intention of the fiction .

  9. An Explicit Approach Toward Modeling Thermo-Coupled Deformation Behaviors of SMPs

    Directory of Open Access Journals (Sweden)

    Hao Li

    2017-03-01

    Full Text Available A new elastoplastic J 2 -flow models with thermal effects is proposed toward simulating thermo-coupled finite deformation behaviors of shape memory polymers. In this new model, an elastic potential evolving with development of plastic flow is incorporated to characterize the stress-softening effect at unloading and, moreover, thermo-induced plastic flow is introduced to represent the strain recovery effect at heating. It is shown that any given test data for both effects may be accurately simulated by means of direct and explicit procedures. Numerical examples for model predictions compare well with test data in literature.

  10. Deformation and fatigue behaviors of carburized automotive gear steel and predictions

    Directory of Open Access Journals (Sweden)

    Bonglae Jo

    2016-07-01

    Full Text Available The fatigue behavior of carburized components such as automotive transmission gears is very complex due to hardness and microstructure difference, residual stresses and multi-axial stress states developed between the case and the core. In addition, automotive gears in service, commonly used in helical type, are actually subjected to complex stress conditions such as bending, torsion, and contact stress states. This study presents experimental and analytical results on deformation behavior of carburized steels, widely used in automotive gears, under cyclic stress conditions including axial and torsion loadings. Axial fatigue tests and rotating bending fatigue tests are also included. Predictions of cyclic deformation and fatigue behaviors of the carburized steel with two-layer model are compared with experimental results. The carburized steel investigated in this study exhibited cyclic softening under both axial loading and torsional loading. Predicted results with simple two-layer model for the cyclic deformation and fatigue behaviors were comparatively similar to the experimental data.

  11. Constitutive Modeling for Flow Behaviors of Superaustenitic Stainless Steel S32654 during Hot Deformation

    Institute of Scientific and Technical Information of China (English)

    En-xiang PU; Han FENG; Min LIU; Wen-jie ZHENG; Han DONG; Zhi-gang SONG

    2016-01-01

    Hot deformation behavior of superaustenitic stainless steel S32654 was investigated with hot compression tests at temperatures of 950-1 250 ℃ and strain rates of 0�001-10 s-1 .Above 1 150 ℃,with strain rate lower than 0�1 s-1 ,the flow curves exhibit nearly steady-state behavior,while at higher strain rate,continuous flow softening occurs.To provide a precise prediction of flow behavior for the alloy,the constitutive modeling considering effect of strain was derived on the basis of the obtained experimental data and constitutive relationship which incorporated Ar-rhenius term and hyperbolic-sine type equation.The material constantsα,n,Q and lnA are found to be functions of the strain and can be fitted employing eighth-order polynomial.The developed constitutive model can be employed to describe the deformation behavior of superaustenitic stainless steel S32654.

  12. Hot Deformation Behavior and Processing Maps of 2099 Al-Li Alloy

    Science.gov (United States)

    Chen, Bin; Tian, Xiao-lin; Li, Xiao-ling; Lu, Chen

    2014-06-01

    Hot deformation behavior and processing maps of the 2099 Al-Li alloy are investigated by tensile test at the temperature range from 250 to 450 °C and the strain rate range from 0.001 to 5.0 s-1. The typical true stress-true strain curves show that the flow stress increases with increasing the strain rate and decreasing the deforming temperature. All curves exhibit rapid work hardening at an initial stage of strain followed by remarkable dynamic softening. Based on the flow stress behavior, the processing maps are calculated and analyzed according to the dynamic materials model (DMM). The processing maps exhibit an instability domain in the temperature and strain rate ranges: T = 250-260 °C and = 0.1-0.5 s-1. The maps also exhibit an optimum hot working condition in the stability domain that occurs in the temperature of 400 °C for a strain rate of 0.001 s-1 and having a maximum efficiency of 60%. The microstructural examinations exhibit the occurrence of dynamic recovery (DRV) during hot deformation of the 2099 alloy which is the dominant softening mechanism in the alloy. The fracture behavior changes from a brittle fracture to a ductile fracture as strain rate decreases and temperature increases.

  13. Effects of heating and cooling rate on transformation behaviors in weld heat affected zone of low carbon steel; Teitanso koban no yosetsu netsu eikyobu no hentai kyodo ni oyobosu kanetsu reikyaku sokudo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Kanetsuki, Y.; Katsumata, M. [Kobe Steel, Ltd., Kobe (Japan)

    1998-01-25

    Discussions were given on effects of welding heat cycles on transformation behaviors in a weld heat affected zone (HAZ). Test pieces are low-carbon fine ferrite pearlite organization steel sheets, which have been treated with a thermomechanical control process (TMCP). The heat cycling was experimented at a maximum temperature of 1350 degC by using a high-frequency heating coil, heating rates from 0.15 to 200 degC/s, cooling rates from 10 to 80 degC/s at an elevated temperature region (higher than 900 degC), and transformation regions (lower than 900 degC) from 0.5 to 6 degC. A transformation curve in actual welding heat cycling was interpreted from these results. Shear-type inverse transformation (from ferrite to austenite) occurs in a rate region corresponding to the heating rate realized during welding. Austenite containing internal stress and a lower structure formed by this inverse transformation accelerates transformation into grain boundary ferrite (GBF) and acerous ferrite (AF). On the other hand, slow cooling in the elevated temperature region releases the internal stress, restores the lower structure, and suppresses the GBF and AF transformation. The GBF tends to precipitate pearlite in adjacent regions and deteriorates the HAZ tenacity. 17 refs., 8 figs., 1 tab.

  14. High-temperature low cycle fatigue behavior of a gray cast iron

    Energy Technology Data Exchange (ETDEWEB)

    Fan, K.L., E-mail: 12klfan@tongji.edu.cn; He, G.Q.; She, M.; Liu, X.S.; Lu, Q.; Yang, Y.; Tian, D.D.; Shen, Y.

    2014-12-15

    The strain controlled low cycle fatigue properties of the studied gray cast iron for engine cylinder blocks were investigated. At the same total strain amplitude, the low cycle fatigue life of the studied material at 523 K was higher than that at 423 K. The fatigue behavior of the studied material was characterized as cyclic softening at any given total strain amplitude (0.12%–0.24%), which was attributed to fatigue crack initiation and propagation. Moreover, this material exhibited asymmetric hysteresis loops due to the presence of the graphite lamellas. Transmission electron microscopy analysis suggested that cyclic softening was also caused by the interactions of dislocations at 423 K, such as cell structure in ferrite, whereas cyclic softening was related to subgrain boundaries and dislocation climbing at 523 K. Micro-analysis of specimen fracture appearance was conducted in order to obtain the fracture characteristics and crack paths for different strain amplitudes. It showed that the higher the temperature, the rougher the crack face of the examined gray cast iron at the same total strain amplitude. Additionally, the microcracks were readily blunted during growth inside the pearlite matrix at 423 K, whereas the microcracks could easily pass through pearlite matrix along with deflection at 523 K. The results of fatigue experiments consistently showed that fatigue damage for the studied material at 423 K was lower than that at 523 K under any given total strain amplitude. - Highlights: • The low cycle fatigue behavior of the HT250 for engine cylinder blocks was investigated. • TEM investigations were conducted to explain the cyclic deformation response. • The low cycle fatigue cracks of HT250 GCI were studied by SEM. • The fatigue life of the examined material at 523 K is higher than that at 423 K.

  15. The relationship between the exam anxiety of the female students preparing for university exam and their menstrual cycle problemsÜniversite sınavına hazırlanan kız öğrencilerin sınav kaygıları ile adet sorunları arasındaki ilişki

    Directory of Open Access Journals (Sweden)

    Yasemin Şanlı

    2015-02-01

    Full Text Available The objective of the study is to determine the relationship between the exam anxiety of the female students preparing for university entrance exam and their menstrual cycle problems. The population of the study is composed of final year female students (n=833 of the high schools in the province of Duzce in 2012-2013 educational year, and the sample of the study is composed of the female students  accepting to take part in the study from the high schools except for the vocational ones (n=502.  Daily Menstrual Symptom Evaluation Scale, and Exam Anxiety Inventory were used in the study for demographic information of the female students. It is determined at the end of the study that the female students preparing for the university entrance exam mostly suffered from menstrual pain and that their exam anxiety levels are high, that university entrance exam caused stress, and that the female students who considers passing the exam as the most important thing in their lives had irregular periods and the higher their exam anxiety is, the more complains they had in their menstrual cycles. ÖzetBu araştırmanın amacı üniversite sınavına hazırlanan kız öğrencilerin sınav kaygıları ile menstruel siklus (adet sorunları arasındaki ilişkiyi belirlemektir. Araştırmanın evrenini 2012-2013 eğitim-öğretim yılında Düzce il merkezine bağlı liselerin son sınıfında okuyan kız öğrenciler (n=833, örneklemini ise meslek liseleri dışındaki liselerin son sınıfında okuyan, çalışmaya katılmayı kabul eden kız öğrenciler (n=502 oluşturmuştur. Veri toplamada kızların genel özelliklerini sorgulayan anket formu, Günlük Menstruel Semptom Değerlendirme Ölçeği ve Sınav Kaygısı Envanteri kullanılmıştır. Çalışma sonucunda, üniversite sınavına hazırlanan kız öğrencilerin çok büyük bir çoğunluğunun adet sancısı yaşadığı, sınav kaygılarının yüksek olduğu, üniversite sınavının kız

  16. Zihin engelli birey için hazırlanan akran aracılı sosyal beceri öğretim programının etkiliğini incelenmesi

    Directory of Open Access Journals (Sweden)

    Elif Sazak Pınar

    2003-07-01

    Full Text Available Bu araştırmanın amacı, akran aracılı sosyal beceri öğretim programının, zihin engelli öğrencinin “kendini tanıtma”, “yardım ya da bilgi isteme” ve “paylaşma” becerilerini kazanmasında etkili olup olmadığını ortaya koymaktır. Araştırmaya, Bolu ilinde bulunan bir ilköğretim okulunun 1. sınıfına devam eden normal gelişim gösteren iki öğrenci ile aynı okulun özel eğitim sınıfına devam eden bir öğrenci katılmıştır. Araştırmada, tek denekli araştırma yöntemlerinden Becerilerarası Çoklu Yoklama Modeli kullanılmıştır. Hedef sosyal beceriler olan; kendini tanıtma, yardım ya da bilgi isteme ve paylaşma becerilerinin akran aracılığıyla zihin engelli öğrenciye kazandırılması için, akran aracılı öğretim yöntemine dayalı öğretim planları geliştirilmiştir. Geliştirilen öğretim planları, haftada 30 dakikalık oturumlar şeklinde uygulanmıştır. Öğretim oturumları sonunda, izleme oturumları yapılmıştır. Araştırmanın sonunda, akran aracılı sosyal beceri öğretiminin, öğrenciye öğretilmesi hedeflenen kendini tanıtma, yardım ya da bilgi isteme ve paylaşma becerilerinin kazandırılmasında etkili olduğu görülmüştür. The purpose of this study was to present the effectiveness of Peer Tutoring Socaial Skills Intervention Program in acquisition of “self-introduction”, “asking for information or help”, and “sharing skills” sby student with mental retardation. Two normally developing first graders, attending to a regular classroom, an done student, attending to a self-contained special education classroom of the same primary school in Bolu, participated in this study. Multiple probe model with probe condition across behavior, which is one of the single subject research designs, was used for this research. The intervention programs were developed to make the student with mental retardation acquire self-introduction, asking for information

  17. Effects of cold work and stress on oxidation and SCC behavior of stainless steels in PWR primary water environments

    Energy Technology Data Exchange (ETDEWEB)

    Shoji, T.; Sakaguchi, K.; Lu, Z. [Fracture and Reliability Research Institute, Tohoku University, Sendai City 980-8579 (Japan); Hirano, S.; Hasegawa, Y. [Kansai Electric Power Co (Japan); Kobayashi, T.; Fujimoto, K.; Nomura, Y. [Mitsubishi Heavy Industries (Japan)

    2011-07-01

    Intergranular stress corrosion cracking (SCC) samples taken from a weld HAZ of 316 stainless steel welded to a low alloy steel of steam generator nozzle with nickel base alloy 82 in Mihama Unit 2 PWR plant were analyzed by extensive metallographic observation, micro-Raman spectroscopy, TEM analysis of stainless steel material, oxide morphology, compositional profiles as well as their crystal structures. The crack growth history during the plant operation is discussed in connection to a residual stress distribution at HAZ and distribution of oxides on/in the cracks. Possible time dependence of crack growth rate with crack growth in components was proposed based upon the evidences observed about oxides. The importance of surface integrity assessment in SCC initiation and propagation is emphasized from a point of view of oxidation localization which can be promoted by strain (dislocation density), straining and stress, which play a crucial role in oxidation due to accelerated mass transfer in oxides as well as underlying metallic materials. Especially, preferential oxidation along slip bands suggests that oxygen diffusion in such a region with a high dislocation density is faster than the other region. This fact implies that grain boundary can also be a preferential path of oxidation as has been observed by TEM, TOFSIMS and 3D-APT. This localization of oxidation and acceleration is discussed based upon an analysis of profile development at a stressed oxide/metal interface. The effects of environmental parameters, temperature, loading mode, and rolling procedures on SCC of stainless steels in simulated PWR environments were investigated by laboratory tests. Strong interactions among grain boundary structure, environmental parameters and interfacial oxidation kinetics, and SCC behavior are observed

  18. Behavioral coaching.

    Science.gov (United States)

    Seniuk, Holly A; Witts, Benjamin N; Williams, W Larry; Ghezzi, Patrick M

    2013-01-01

    The term behavioral coaching has been used inconsistently in and outside the field of behavior analysis. In the sports literature, the term has been used to describe various intervention strategies, and in the organizational behavior management literature it has been used to describe an approach to training management personnel and staff. This inconsistency is problematic in terms of the replication of behavioral coaching across studies and aligning with Baer, Wolf, and Risley's (1968) technological dimension of applied behavior analysis. The current paper will outline and critique the discrepancies in the use of the term and suggest how Martin and Hrycaiko's (1983) characteristics of behavioral coaching in sports may be used to bring us closer to establishing a consistent definition of the term. In addition, we will suggest how these characteristics can also be applicable to the use of the term behavioral coaching in other domains of behavior analysis.

  19. Verbal behavior

    OpenAIRE

    Michael, Jack

    1984-01-01

    The recent history and current status of the area of verbal behavior are considered in terms of three major thematic lines: the operant conditioning of adult verbal behavior, learning to be an effective speaker and listener, and developments directly related to Skinner's Verbal Behavior. Other topics not directly related to the main themes are also considered: the work of Kurt Salzinger, ape-language research, and human operant research related to rule-governed behavior.

  20. Verbal behavior

    OpenAIRE

    Michael, Jack

    1984-01-01

    The recent history and current status of the area of verbal behavior are considered in terms of three major thematic lines: the operant conditioning of adult verbal behavior, learning to be an effective speaker and listener, and developments directly related to Skinner's Verbal Behavior. Other topics not directly related to the main themes are also considered: the work of Kurt Salzinger, ape-language research, and human operant research related to rule-governed behavior.

  1. Deformation behavior of dispersion-strengthened copper at high temperature

    Institute of Scientific and Technical Information of China (English)

    WANG Mengjun; ZHANG Yingchun; LUO Yun; LIU Xinyu

    2006-01-01

    The deformation behavior of dispersion-strengthened copper with different compositions was investigated by hot compression simulation tests on a Gleeble-1500 thermal-mechanical simulator. The microstructure during deformation at high temperature was also studied. The result shows that at the beginning of hot compression simulation, the flowing stress of the dispersion-strengthened copper quickly attains a peak value and the stress shows a greater decrease when the temperature is higher and the strain rate is lower. The dispersion particles lead to an obvious increase in the recrystallization temperature. Under experimental conditions, dynamic recovery is the main softening method. The constitutive equation at high temperature of 1.2%Al2O3-0.4%WC/Cu is obtained.

  2. Investigation on hot deformation behavior of AZ31 madnesium alloy

    Institute of Scientific and Technical Information of China (English)

    汪凌云; HUANG; Guangsheng; 等

    2002-01-01

    The hot compressive deformation of extruded AZ31 magnesium alloy with the mass fractions of Al and Zn equal to 3%and 1% respectively is studied by a Gleeble-1500D thermal mechanical simulator over the temperature range from 200℃to 400℃ and the strain rate from 10-3 s-1 to 100s-1.The true stress-strain curves of the strain of 65% are tested.The deformation activation energy is obtained and the flow stress model is established by analyzng the effects of strain rate and temperature on the flow stress.Zener-Hollomon parameter is introduced to describe the softening behaviors of AZ31 magnesium alloy resulted from dynamic recrystallization during the hot compressive deformation,whose natural logarithm is linear with the critical strain of dynamic recrystallization.

  3. Influence of bending test configuration on cracking behavior of FRC

    DEFF Research Database (Denmark)

    Finazzi, Silvia; Paegle, Ieva; Fischer, Gregor;

    2014-01-01

    This paper describes an investigation of the influence of the testing configuration for Fiber Reinforced Concrete in bending and aims at evaluating the influence of the test configuration details on the characterization of the material. Two different types of FRC, Steel Fiber Reinforced Concrete...... (SFRC) and Engineered Cementitious Composites (ECC), were tested and are described in this study. The materials were chosen so that one of them would be strain hardening (ECC) and the other tension softening (SFRC). Notched and un-notched three- and four-point bending tests were carried out to determine...... the flexural load-deformation response of FRC. This research focuses particularly on the influence of the appearance and depth of the notch on the cracking behavior of FRC. For this purpose, several specimens, both un-notched and notched with different depths of the notch (25 mm and 45 mm), were tested...

  4. Nonlinear behavior analysis of spur gear pairs with a one-way clutch

    Science.gov (United States)

    Gill-Jeong, Cheon

    2007-04-01

    Nonlinear behavior analysis of a paired spur gear system with a one-way clutch was used to verify whether a one-way clutch is effective for reducing torsional vibration. The dynamic responses were studied over a wide frequency range by speed sweeping to check the nonlinear behavior using numerical integration. The gear system with a one-way clutch showed typical nonlinear behavior, such as softening nonlinearity and jump phenomena. The oscillating component of the dynamic transmission error was reduced over the entire frequency range compared to a system without a one-way clutch, and double-side contact could be prevented, even with very small backlash. Installing a one-way clutch on both sides of the gear system was more effective at mitigating the negative effects of various parameter changes than installing one only on the input or output side.

  5. Nonlinear behavior of ionically and covalently cross-linked alginate hydrogels

    Science.gov (United States)

    Hashemnejad, Seyedmeysam; Zabet, Mahla; Kundu, Santanu

    2015-03-01

    Gels deform differently under applied load and the deformation behavior is related to their network structures and environmental conditions, specifically, strength and density of crosslinking, polymer concentration, applied load, and temperature. Here, we investigate the mechanical behavior of both ionically and covalent cross-linked alginate hydrogel using large amplitude oscillatory shear (LAOS) and cavitation experiments. Ionically-bonded alginate gels were obtained by using divalent calcium. Alginate volume fraction and alginate to calcium ratio were varied to obtain gels with different mechanical properties. Chemical gels were synthesized using adipic acid dihdrazide (AAD) as a cross-linker. The non-linear rheological parameters are estimated from the stress responses to elucidate the strain softening behavior of these gels. Fracture initiation and propagation mechanism during shear rheology and cavitation experiments will be presented. Our results provide a better understanding on the deformation mechanism of alginate gel under large-deformation.

  6. Periodic behaviors

    CERN Document Server

    Napp, Diego; Shankar, Shiva

    2010-01-01

    This paper studies behaviors that are defined on a torus, or equivalently, behaviors defined in spaces of periodic functions, and establishes their basic properties analogous to classical results of Malgrange, Palamodov, Oberst et al. for behaviors on R^n. These properties - in particular the Nullstellensatz describing the Willems closure - are closely related to integral and rational points on affine algebraic varieties.

  7. PERIODIC BEHAVIORS

    NARCIS (Netherlands)

    Napp, Diego; Put, Marius van der; Shankar, Shiva

    2010-01-01

    This paper studies behaviors that are defined on a torus, or equivalently, behaviors defined in spaces of periodic functions, and establishes their basic properties analogous to classical results of Malgrange, Palamodov, Oberst et al. for behaviors on R(n). These properties-in particular the Nullste

  8. Behaviorally Speaking.

    Science.gov (United States)

    Porter, Elias H.; Dutton, Darell W. J.

    1987-01-01

    Consists of two articles focusing on (1) a modern behavioral model that takes cues from Hippocrates' Four Temperaments and (2) use of a behavioral approach to improve the effectiveness of meetings. Lists positive and negative behaviors within the meeting context. (CH)

  9. Behavior Of Austempered Ductile Irons (ADI) Subjected To Laser Surface Melting

    Science.gov (United States)

    Jones, D. L.; Fagoaga, I.; Liceaga, J. F.; Sanz Justes, Pedro; Jasnowski, Kazie S.

    1989-03-01

    The near surface microstructure of 3 austempered ductile irons has been modified using laser surface melting (LSM). A white cast iron layer was produced to depths of up to 500 microns. The microstructure of this region varied depending upon the parameters used. A heat affected zone (HAZ) appeared at an abrupt transition between the LSM zone and the substrate. The size of the HAZ, which varied between 20 and 200 microns was predominately affected by the pass velocity in the range of energies used. The hardness profiles showed large variations in the Haz probably due to varing tempering effects from the subsequent passes.

  10. Preparation of two ester-containing Gemini quaternary ammonium softener and its properties%双酯基Gemini季铵盐柔软剂的制备及性能

    Institute of Scientific and Technical Information of China (English)

    娄平均; 朱红军; 丁徽; 牛华

    2011-01-01

    A di-ester Gemini quaternary ammonium softener( DEGOS) is prepared with dimethyl stearic acid ethyl tertiary amine and 1,3-dichloro-2-propanol as raw materials. The optimum synthesis conditions ara determined via orthogonal experiments as follows∶reaction at 80 ℃ for 12 hours with n( 1 , 3-dichloro-2-propanol) ∶ n ( dimethyl stearic acid ethyl tertiary amine) = 1 ∶ 2.1and ethanol of 40% , and the yield reaches 89.3%. The product is characterized by FTIR, elemental analysis and 1H-NMR, and its application properties are studied. The results show that the product features good surface activity with surface tension of 35.9 mN/m, critical micelle concentration of 0.039 mmol/L and Krafft point of - 3.41 ℃, good softening property similar to that of commercial softener D1821, and good rewetting property and biodegradability, as well as low influence on whiteness of the fabric.%以二甲基硬脂酸乙酯基叔胺和l,3-二氯-2-丙醇为原料,合成了一种双酯基Gemini季铵盐织物柔软剂(DEGQS).通过正交试验考察了反应的影响因素,确定优化工艺条件为:n(1,3-二氯-2-丙醇):n(二甲基硬脂酸乙酯基叔胺)=1:2.1,反应温度80℃,W(乙醇)=40%(占反应物总量的质量分数),反应时间12 h,在该条件下目标产物的收率达到89.3%.通过FTIR、元素分析和1H-NMR对DEGQS进行表征,并研究其应用性能,结果表明,该柔软剂的表面张力35.9 mN/m,临界胶束浓度0.039 mmol/L,Krafft点为-3.41℃,表面活性较好,柔软性能与D1821基本相当,具有优良的再润湿性和生物降解性能,对织物的白度影响较小.

  11. Modeling of high homologous temperature deformation behavior for stress and life-time analyses

    Energy Technology Data Exchange (ETDEWEB)

    Krempl, E. [Rensselaer Polytechnic Institute, Troy, NY (United States)

    1997-12-31

    Stress and lifetime analyses need realistic and accurate constitutive models for the inelastic deformation behavior of engineering alloys at low and high temperatures. Conventional creep and plasticity models have fundamental difficulties in reproducing high homologous temperature behavior. To improve the modeling capabilities {open_quotes}unified{close_quotes} state variable theories were conceived. They consider all inelastic deformation rate-dependent and do not have separate repositories for creep and plasticity. The viscoplasticity theory based on overstress (VBO), one of the unified theories, is introduced and its properties are delineated. At high homologous temperature where secondary and tertiary creep are observed modeling is primarily accomplished by a static recovery term and a softening isotropic stress. At low temperatures creep is merely a manifestation of rate dependence. The primary creep modeled at low homologous temperature is due to the rate dependence of the flow law. The model is unaltered in the transition from low to high temperature except that the softening of the isotropic stress and the influence of the static recovery term increase with an increase of the temperature.

  12. Influence of Prior Fatigue Cycling on Creep Behavior of Reduced Activation Ferritic-Martensitic Steel

    Science.gov (United States)

    Sarkar, Aritra; Vijayanand, V. D.; Parameswaran, P.; Shankar, Vani; Sandhya, R.; Laha, K.; Mathew, M. D.; Jayakumar, T.; Rajendra Kumar, E.

    2014-06-01

    Creep tests were carried out at 823 K (550 °C) and 210 MPa on Reduced Activation Ferritic-Martensitic (RAFM) steel which was subjected to different extents of prior fatigue exposure at 823 K at a strain amplitude of ±0.6 pct to assess the effect of prior fatigue exposure on creep behavior. Extensive cyclic softening that characterized the fatigue damage was found to be immensely deleterious for creep strength of the tempered martensitic steel. Creep rupture life was reduced to 60 pct of that of the virgin steel when the steel was exposed to as low as 1 pct of fatigue life. However, creep life saturated after fatigue exposure of 40 pct. Increase in minimum creep rate and decrease in creep rupture ductility with a saturating trend were observed with prior fatigue exposures. To substantiate these findings, detailed transmission electron microscopy studies were carried out on the steel. With fatigue exposures, extensive recovery of martensitic-lath structure was distinctly observed which supported the cyclic softening behavior that was introduced due to prior fatigue. Consequently, prior fatigue exposures were considered responsible for decrease in creep ductility and associated reduction in the creep rupture strength.

  13. Making Behavioral Activation More Behavioral

    Science.gov (United States)

    Kanter, Jonathan W.; Manos, Rachel C.; Busch, Andrew M.; Rusch, Laura C.

    2008-01-01

    Behavioral Activation, an efficacious treatment for depression, presents a behavioral theory of depression--emphasizing the need for clients to contact positive reinforcement--and a set of therapeutic techniques--emphasizing provision of instructions rather than therapeutic provision of reinforcement. An integration of Behavioral Activation with…

  14. Deformation Behavior and Microstructure Evolution of As-Cast 42CrMo Alloy in Isothermal and Non-isothermal Compression

    Science.gov (United States)

    Qin, Fangcheng; Li, Yongtang; Qi, Huiping; Lv, Zhenhua

    2016-11-01

    The isothermal and non-isothermal multi-pass compression tests of centrifugal casting 42CrMo steel were conducted on a Gleeble-3500 thermal simulation machine. The effects of compression passes and finishing temperatures on deformation behavior and microstructure evolution were investigated. It is found that the microstructure is homogeneous with equiaxed grains, and the flow stress does not show significant change with the increase in passes, while the peak softening coefficient increases first and then decreases during inter-pass. Moreover, the dominant mechanisms of controlled temperature and accumulated static recrystallization for grain refinement and its homogeneous distribution are found after 5 passes deformation. As the finishing temperature increases, the flow stress decreases gradually, but the dynamic recrystallization accelerates and softening effect increases, resulting in the larger grain size and homogeneous microstructure. The microhardness decreases sharply because the sufficient softening occurs in microstructure. When the finishing temperature is 890 °C, the carbide particles are precipitated in the vicinity of the grain boundaries, thus inhibiting the dislocation motion. Thus, the higher finishing temperature (≥970 °C) for centrifugal casting 42CrMo alloy should be avoided in non-isothermal multi-pass deformation, which is beneficial to grain refinement and properties improvement.

  15. An Experimental Investigation of the Dynamic Behavior of an In-Plane MEMS Shallow Arch Under Electrostatic Excitation

    KAUST Repository

    Ramini, Abdallah

    2016-01-20

    We present experimental investigation of the nonlinear dynamics of a clamped-clamped in-plane MEMS shallow arch when excited by an electrostatic force. We explore the dynamic behaviors of the in-plane motion of the shallow arches via frequency sweeps in the neighborhood of the first resonance frequency. The shallow arch response is video microscopy recorded and analyzed by means of digital imaging. The experimental data show local softening behavior for small DC and AC loads. For high voltages, the experimental investigation reveals interesting dynamics, where the arch exhibits a dynamic snap-Through behavior. These attractive experimental results verify the previously reported complex behavior of in-plane MEMS arches and show promising results to implement these structures for variety of sensing and actuation applications. © Copyright 2015 by ASME.

  16. On softened water reverse osmosis centralized control scheme and common defect analysis%软化水反渗透系统集控方案及常见故障分析

    Institute of Scientific and Technical Information of China (English)

    张琦

    2015-01-01

    介绍了软化水反渗透系统的主要包含部分及功能,着重对该系统常见的故障进行了原因分析,主要有RO增压泵不工作、计量泵不工作、反渗透产水量下降等问题,以制定出有效的解决措施,保证系统的正常运行。%The paper introduces the main parts and functions of the softened water reverse osmosis system,analyzes reasons for common defects of the system,including the insufficiency in the RO booster pump and metering pump,and lower water yield of the reverse osmosis,so as to make the effective solutions and ensure the common operation of the system.

  17. Bond Stretching Phonon Softening And Kinks in the Angle-Resolved Photoemission Spectra of Optimally Doped Bi(2)Sr(1.6)La(0.4)Cu(2)O(6)+-Delta Superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Graf, J.; d' Astuto, M.; Jozwiak, C.; Garcia, D.R.; Saini, N.L.; Krisch, M.; Ikeuchi, K.; Baron, A.Q.R.; Eisaki, H.; Lanzara, A.

    2009-05-19

    We report the first measurement of the Cu-O bond stretching phonon dispersion in optimally doped Bi{sub 2}Sr{sub 1.6}La{sub 0.4}Cu{sub 2}O{sub 6+{delta}} using inelastic x-ray scattering. We found a softening of this phonon at q = ({approx} 0.25, 0, 0) from 76 to 60 meV, similar to the one reported in other cuprates. A comparison with angle-resolved photoemission data on the same sample revealed an excellent agreement in terms of energy and momentum between the angle-resolved photoemission nodal kink and the soft part of the bond stretching phonon. Indeed, we find that the momentum space where a 63 {+-} 5 meV kink is observed can be connected with a vector q = ({zeta}, 0, 0) with {zeta} {ge} 0.22, corresponding exactly to the soft part of the bond stretching phonon.

  18. Bond stretching phonon softening and angle-resolved photoemission kinks in optimally doped Bi2Sr1:6La0:4Cu2O6+sigma superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Graf, Jeff; d& #39; Astuto, M.; Jozwiak, C.; Garcia, D.R.; Saini, N.L.; Krisch, M.; Ikeuchi, K.; Baron, A.Q.R.; Eisaki, H.; Lanzara, Alessandra

    2008-05-08

    We report the first measurement of the Cu-O bond stretching phonon dispersion in optimally doped Bi2Sr1.6La0.4Cu2O6+delta using inelastic x-ray scattering. We found a softening of this phonon at q=(0.25,0,0) from 76 to 60 meV, similar to the one reported in other cuprates. A comparison with angle-resolved photoemission data on the same sample revealed an excellent agreement in terms of energy and momentum between the angle-resolved photoemission nodal kink and the soft part of the bond stretching phonon. Indeed, we find that the momentum space where a 63+-5 meV kink is observed can be connected with a vector q=(xi,0,0) with xi>= 0.22, corresponding exactly to the soft part of the bond stretching phonon.

  19. Monte Carlo and theoretical calculations of the first four perturbation coefficients in the high temperature series expansion of the free energy for discrete and core-softened potential models

    Science.gov (United States)

    Zhou, Shiqi; Solana, J. R.

    2013-06-01

    The first four perturbation coefficients in the expansion of the Helmholtz free energy in power series of the inverse of the reduced temperature for a number of potential models with hard-sphere cores plus core-softened and discontinuous tails are obtained from Monte Carlo simulations. The potential models considered include square-well, double square-well, and square-shoulder plus square-well, with different potential parameters. These simulation data are used to evaluate the performance of a traditional macroscopic compressibility approximation (MCA) for the second order coefficient and a recent coupling parameter series expansion (CPSE) for the first four coefficients. Comprehensive comparison indicates the incapability of the MCA for the second order coefficient in most non-stringent situations, and significance of the CPSE in accurately calculating these four coefficients.

  20. Process optimisation of lime milk leaching and control of cold lime softening at the power plant STEAG Fenne; Optimierung des Kalkansatzes und Regelung der Kalkmilchdosierung in der KZA des STEAG-Kraftwerks Fenne

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Christian [Steag Kraftwerk Fenne, Voelklingen (Germany). Anlagentechnik; Arenz, Helmut [Steag Kraftwerk Fenne, Voelklingen (Germany). Technischer Service; Wysk, Ralf [NALCO Deutschland GmbH, Frankfurt am Main (Germany). National Account Managing Kraftwerke

    2013-06-01

    An increase in turbidity in the cleaned water of the cold lime softener higher than the raw water input of the river Saar was observed at the Fenne site at some days in 2009. Also the post-installed sand filter could not restrain the fine particles. Under these circumstances the demineralisation water production had serious problems because of heavily fouled membranes in the reverse osmosis system. Only the immense personal actions of the operating staff could enable the reliability of the water preparation system on site. Together with Nalco the power plant service department implemented a plant audit on site. The purpose of the plant audit was to find the reason for the bottleneck in water preparation and to optimise and automate the water treatment system under the aspects of economical reliability and control efficiency. (orig.)

  1. Psychological behaviorism and behaviorizing psychology

    Science.gov (United States)

    Staats, Arthur W.

    1994-01-01

    Paradigmatic or psychological behaviorism (PB), in a four-decade history of development, has been shaped by its goal, the establishment of a behaviorism that can also serve as the approach in psychology (Watson's original goal). In the process, PB has become a new generation of behaviorism with abundant heuristic avenues for development in theory, philosophy, methodology, and research. Psychology has resources, purview and problem areas, and nascent developments of many kinds, gathered in chaotic diversity, needing unification (and other things) that cognitivism cannot provide. Behaviorism can, within PB's multilevel framework for connecting and advancing both psychology and behaviorism. PMID:22478175

  2. Psychological behaviorism and behaviorizing psychology.

    Science.gov (United States)

    Staats, A W

    1994-01-01

    Paradigmatic or psychological behaviorism (PB), in a four-decade history of development, has been shaped by its goal, the establishment of a behaviorism that can also serve as the approach in psychology (Watson's original goal). In the process, PB has become a new generation of behaviorism with abundant heuristic avenues for development in theory, philosophy, methodology, and research. Psychology has resources, purview and problem areas, and nascent developments of many kinds, gathered in chaotic diversity, needing unification (and other things) that cognitivism cannot provide. Behaviorism can, within PB's multilevel framework for connecting and advancing both psychology and behaviorism.

  3. D_3合成氨基硅油在织物柔软整理中的应用%Application of D3 Synthesized Amino- Silicone Oil in Fabric Softening and Finishing

    Institute of Scientific and Technical Information of China (English)

    杜高敏; 单巨川; 郑庆康; 冯西宁

    2012-01-01

    采用六甲基环三硅氧烷(D3)合成不同氨值的羟基、甲基和甲氧基封端氨基硅油乳液并将其用于纯棉、涤/棉织物进行柔软整理,通过分析氨值、封端剂对整理后织物的手感、白度、强力、平均弯曲长度等指标的影响,得出D3合成氨基硅油对纺织品柔软整理的可行性。试验结果表明,通常情况下,随着氨值增加,整理后织物的手感变好、平均弯曲长度变小、强力下降、白度稍有降低;具有活性封端剂的氨基硅油整理织物的柔软性要优于非活性封端剂氨基硅油。%Hydroxyl, methyl and methoxyl terminal amino - silicone emulsion with different amine values synthesized by using D3 (hexamethylcyclotrisioxane) was applied to the softening and finishing of pure cotton of softening and finishing of D3 synthesized amino - silicone oil for fabric was concluded. The experiment showed that with the increase of amine value, the handle of fabric was better, average bending length was shortened and whiteness was decreased after finishing, the softness of fabric finished by amino - silicone oil with active end - capping reagent was better than the one with non - active end - capping reagent.

  4. 半水石膏-矿渣胶凝材料力学性能及软化系数研究%Research on Mechanical Properties and Softening Coefficient of Hemihydrate-slag Cement

    Institute of Scientific and Technical Information of China (English)

    李书琴; 艾永平; 刘利军; 黄晓明

    2011-01-01

    In this paper, mechanical properties and softening coefficient of hemihydrate-slag cement with different additives and curing system are studied. The results show that the change in the amount of cement clinker has no obvious effect on its strength; retardant slurry could control the types of minerals in the formation mechanism and change the quantity, scale of the hydration product in half water gypsum condensation, hardening, and impact the structure of the hardening; the strength of sample has little difference from maintenance system 1 (standard curing) and maintenance system 2( natural maintenance ),but the softening coefficient is high in maintenance system 2; besides dihydrate gypsum.%本文研究了外加剂(水泥熟料和柠檬酸盐缓凝剂)和养护制度对石膏-矿渣胶凝材料力学性能和软化系数的影响.结果表明:水泥熟料量的变化对其强度影响不明显;缓凝剂可以控制浆体中各类矿物的生成机制,改变水化产物在半水石膏凝结、硬化前的数量、比例及影响硬化体的结构组成;养护制度1(标准养护)和养护制度2(自然养护)养护后的试样强度相差不大,但养护制度2条件下养护后所得制品软化系数较高.

  5. Teleological behaviorism.

    Science.gov (United States)

    Rachlin, H

    1992-11-01

    A psychological science of efficient causes, using internal mechanisms to explain overt behavior, is distinguished from another psychological science, based on Aristotelian final causes, using external objects and goals to explain overt behavior. Efficient-cause psychology is designed to answer the question of how a particular act is emitted; final-cause psychology is designed to answer the question of why a particular act is emitted. Physiological psychology, modern cognitive psychology, and some parts of behaviorism including Skinnerian behaviorism are efficient-cause psychologies; final-cause psychology, a development of Skinnerian behaviorism, is here called teleological behaviorism. Each of these two conceptions of causality in psychology implies a different view of the mind, hence a different meaning of mental terms.

  6. Desenvolvimento da ferrita delta na solda e ZTA resultante de soldagem plasma pulsada em um aço inoxidável supermartensítico Delta-ferrite development in weld and HAZ produced by pulsed plasma arc welding in a supermartensitic stainless steel

    Directory of Open Access Journals (Sweden)

    Sérgio L. Henke

    2013-03-01

    Full Text Available A ferrita delta é considerada uma fase indesejável na microestrutura dos aços inoxidáveis martensíticos haja vista a mesma poder influenciar no desempenho da resistência à fadiga, tenacidade e corrosão sob-tensão. Sendo assim, o objetivo deste trabalho foi investigar o efeito da soldagem plasma pulsada sobre a distribuição e quantidade de ferrita delta em um aço inoxidável supermartensítico. Para tal foram obtidos cordões por meio de fusão superficial sobre uma amostra de aço inoxidável supermartensítico de alta liga utilizando corrente pulsada e convencional. Em seguida foi efetuada a caracterização microestrutural, em especial da ferrita delta, via análises metalográficas por meio de microscopia óptica e eletrônica de varredura . Os experimentos revelaram que, para o mesmo aporte térmico, a pulsação de corrente promoveu a formação de ferrita delta na forma de bandas ao longo do cordão de solda e redução significativa desta fase na ZTA quando comparada à soldagem convencional.The objective of this study was to investigate the effect of pulsed plasma welding on the distribution and amount of delta ferrite which is considered an undesirable phase in a supermartensitic stainless steel. For such weld beads have been obtained by melting the surface of a sample of a high-alloy supermartensitic stainless steel using pulsed and conventional current. Microstructural characterization, especially of delta ferrite, was performed by metallographic analysis by means of optical microscopy and scanning electron microscopy. The experiments showed that for the same heat input, pulsed current promoted the formation of delta ferrite in the form of bands along the weld bead and caused a significant reduction of this phase in HAZ as compared to conventional welding.

  7. Behavioral economics.

    Science.gov (United States)

    Camerer, Colin F

    2014-09-22

    Behavioral economics uses evidence from psychology and other social sciences to create a precise and fruitful alternative to traditional economic theories, which are based on optimization. Behavioral economics may interest some biologists, as it shifts the basis for theories of economic choice away from logical calculation and maximization and toward biologically plausible mechanisms.

  8. Aggressive behavior

    NARCIS (Netherlands)

    Didden, H.C.M.; Lindsay, W.R.; Lang, R.; Sigafoos, J.; Deb, S.; Wiersma, J.; Peters-Scheffer, N.C.; Marschik, P.B.; O’Reilly, M.F.; Lancioni, G.E.

    2016-01-01

    Aggressive behavior is common in individuals with intellectual and developmental disabilities (IDDs), and it is most often targeted for intervention. Psychological, contextual, and biological risk factors may contribute to the risk of aggressive behavior. Risk factors are gender (males), level of ID

  9. Aggressive behavior

    NARCIS (Netherlands)

    Didden, H.C.M.; Lindsay, W.R.; Lang, R.; Sigafoos, J.; Deb, S.; Wiersma, J.; Peters-Scheffer, N.C.; Marschik, P.B.; O’Reilly, M.F.; Lancioni, G.E.

    2016-01-01

    Aggressive behavior is common in individuals with intellectual and developmental disabilities (IDDs), and it is most often targeted for intervention. Psychological, contextual, and biological risk factors may contribute to the risk of aggressive behavior. Risk factors are gender (males), level of ID

  10. The Phenomenological Constitutive Description of Dynamic Recrystallization Softening Behavior of AZ80 Magnesium Alloy%AZ80镁合金动态再结晶软化行为的唯象本构描述

    Institute of Scientific and Technical Information of China (English)

    佟莹

    2010-01-01

    采用热物理模拟机Gleeble1500对多组AZ80镁合金试样进行压缩试验,温度范围为250~400℃,应变速率范围为0.01~10s-1.真应力-应变曲线显示,应力迅速达到峰值之后发生软化,峰值应力随应变速率的增加而提高,随试验温度的升高而减小.金相分析表明,变形条件对动态再结晶软化的影响规律描述为:试样压缩60%后,晶粒大小随着应变速率的增加而减小,显微维氏硬度随细化后晶粒尺寸的减小而非线性减小,随应变速率的增加而减小.引入一种包含软化因子的唯象本构模型,并应用多元线性回归方法对相关的系数进行求解,结果发现求解获得的本构方程能够较好地描述AZ80镁合金的流变软化行为.

  11. Monotonic and Cyclic Behavior of DIN 34CrNiMo6 Tempered Alloy Steel

    Directory of Open Access Journals (Sweden)

    Ricardo Branco

    2016-04-01

    Full Text Available This paper aims at studying the monotonic and cyclic plastic deformation behavior of DIN 34CrNiMo6 high strength steel. Monotonic and low-cycle fatigue tests are conducted in ambient air, at room temperature, using standard 8-mm diameter specimens. The former tests are carried out under position control with constant displacement rate. The latter are performed under fully-reversed strain-controlled conditions, using the single-step test method, with strain amplitudes lying between ±0.4% and ±2.0%. After the tests, the fracture surfaces are examined by scanning electron microscopy in order to characterize the surface morphologies and identify the main failure mechanisms. Regardless of the strain amplitude, a softening behavior was observed throughout the entire life. Total strain energy density, defined as the sum of both tensile elastic and plastic strain energies, was revealed to be an adequate fatigue damage parameter for short and long lives.

  12. Constitution modeling and deformation behavior of yttrium bearing TiAl alloy

    Institute of Scientific and Technical Information of China (English)

    CHEN Yuyong; YANG Fei; KONG Fantao; XIAO Shulong

    2011-01-01

    The deformation flow behaviors of Ti-45Al-5.4V-3.6Nb-0.3Y alloy at different temperatures and strain rates were studied by isothermal compressing simulation test. The apparent activation energy of deformation was calculated to be 402.096 kJ/mol and constitutive equation was established to describe the flow behavior. Microstructure and flow softening observations exhibited that Ti-45Al-5.4V-3.6Nb-0.3Y alloy had bad hot workability at low temperature (lower than 1 100 ℃) and high strain rate (higher than 0.5 s-1) characterized by localization deformation and instability. With deformation temperature higher than 1 150 ℃ and strain rate lower than 0.01 s-1, the alloy owned good hot deformability, and plenty of dynamic recrystallized grains could be observed in the deformed microstructures.

  13. Biochemical and nutritional characterization of three prickly pear species with different ripening behavior.

    Science.gov (United States)

    Hernández-Pérez, Talia; Carrillo-López, Armando; Guevara-Lara, Fidel; Cruz-Hernández, Andrés; Paredes-López, Octavio

    2005-12-01

    Biochemical and nutritional changes were studied during the ripening process of three Opuntia morphospecies with different ripening behavior: Naranjona (O. ficus-indica), Blanca Cristalina (Opuntia sp.), and Esmeralda (Opuntia sp.) of early, early-intermediate, and intermediate-late ripening, respectively. In loss of fresh weight, Naranjona showed the highest values, while in Blanca Cristalina and Esmeralda, a discrete weight loss was found. No significant differences were found among morphospecies in soluble solids, total titratable acidity and pH during the postharvest days. Blanca Cristalina and Esmeralda showed an increase in the content of carotenoids, while these diminished in Naranjona. The cell wall enzymes evaluated showed particular behaviors during the ripening of each morphospecies suggesting a fine biochemical control and not a clear relationship between fruit softening and enzyme activity. This study provides basic information on prickly pear ripening, in order to understand this process for its control and for improving shelf life.

  14. Araplara Türkçe Öğretmek Amacıyla Hazırlanmış Kaşgarlı Mahmut Türkçe Öğretim Seti’nde Kültür Aktarımı Cultural Transfer In Mahmud Al Kashgari Turkish Teaching Set Prepared For Teaching Turkish To Arabs

    Directory of Open Access Journals (Sweden)

    İsa YILMAZ

    2013-07-01

    . Dil ile kültür arasında bu şekilde bir alışveriş vardır. Bu ilişkiye dil ve kültürden söz edilen her alanda dikkat edilmesi gerekir. Bu alanlardan olan dil öğretiminde dil ile kültür arasındaki ilişki her aşamada göz önünde bulundurulmalıdır. Çünkü dil öğretimi aynı zamanda kültür aktarımı demektir. Bu sebeple Avrupa Dilleri Öğretimi Ortak Çerçeve Metni’nde de dil öğretiminde kültür aktarımının önemi üzerinde durulmuştur.Bu çalışmada dil öğretiminin kültürlerarası etkileşimde bir araç olduğu düşüncesinden hareketle, öncelikle Türkçe öğretimi amacıyla hazırlanmış olan ders kitaplarının kültür aktarımı sürecindeki yeri ve önemi üzerinde durulmuştur. Daha sonra Araplara Türkçe öğretimi amacıyla hazırlanmış olan Kaşgarlı Mahmut Türkçe Öğretim Seti kültür aktarımı bağlamında ele alınmış ve belirli ölçütlere göre değerlendirilmiştir. Bu incelemeler sonucunda temel seviye metinlerinde orta seviye metinlerine göre daha fazla aktarımın yapıldığı ve yapılan aktarımların da genellikle doğrudan olduğu anlaşılmıştır. Orta seviye metinlerinde ise daha çok edebî ve tarihsel aktarımların yapıldığı görülmüştür. Bu sonuçlara göre Türk yaşantısı ve gelenek-görenekleriyle ilgili ögelere daha fazla yer verilmesi gerektiği düşüncesi oluşmuştur.

  15. Low cycle fatigue behavior of high strength gun steels

    Institute of Scientific and Technical Information of China (English)

    Maoqiu Wang; Han Dong; Qi Wang; Changgang Fan

    2004-01-01

    The low cycle fatigue (LCF) behavior of two high strength steels, with nominal chemical compositions (mass fraction, %)of 0.40C-1.5Cr-3Ni-0.4Mo-0.2V (PCrNi3MoV) and 0.25C-3Cr-3Mo-0.8Ni-0.1Nb (25Cr3Mo3NiNb), was investigated by using the smooth bar specimens subjected to strained-controlled push-pull loading. It is found that both steels show cyclic softening, but 25Cr3Mo3NiNb steel has a lower tendency to cyclic softening. 25Cr3Mo3NiNb steel has higher fatigue ductility, and its transition fatigue life is almost three times that of PCrNi3MoV. 25Cr3Mo3NiNb steel also shows higher LCF life either at a given total strain amplitude above 0.5% or at any given plastic strain amplitude, despite its lower monotonic tensile strength than that of PCrNi3MoV.It also means that 25Cr3Mo3NiNb steel can endure higher total strain amplitude and plastic strain amplitude at a given number of reversals to failure within 104. 25Cr3Mo3NiNb steel is expected to be a good gun steel with high LCF properties because only several thousand firings are required for gun barrel in most cases.

  16. Cost Behavior

    DEFF Research Database (Denmark)

    Hoffmann, Kira

    The objective of this dissertation is to investigate determinants and consequences of asymmetric cost behavior. Asymmetric cost behavior arises if the change in costs is different for increases in activity compared to equivalent decreases in activity. In this case, costs are termed “sticky......” if the change is less when activity falls than when activity rises, whereas costs are termed “anti-sticky” if the change is more when activity falls than when activity rises. Understanding such cost behavior is especially relevant for decision-makers and financial analysts that rely on accurate cost information...

  17. Behavioral epigenetics

    Science.gov (United States)

    Lester, Barry M.; Tronick, Edward; Nestler, Eric; Abel, Ted; Kosofsky, Barry; Kuzawa, Christopher W.; Marsit, Carmen J.; Maze, Ian; Meaney, Michael J.; Monteggia, Lisa M.; Reul, Johannes M. H. M.; Skuse, David H.; Sweatt, J. David; Wood, Marcelo A.

    2013-01-01

    Sponsored by the New York Academy of Sciences, the Warren Alpert Medical School of Brown University and the University of Massachusetts Boston, “Behavioral Epigenetics” was held on October 29–30, 2010 at the University of Massachusetts Boston Campus Center, Boston, Massachusetts. This meeting featured speakers and panel discussions exploring the emerging field of behavioral epigenetics, from basic biochemical and cellular mechanisms to the epigenetic modulation of normative development, developmental disorders, and psychopathology. This report provides an overview of the research presented by leading scientists and lively discussion about the future of investigation at the behavioral epigenetic level. PMID:21615751

  18. Cost Behavior

    DEFF Research Database (Denmark)

    Hoffmann, Kira

    The objective of this dissertation is to investigate determinants and consequences of asymmetric cost behavior. Asymmetric cost behavior arises if the change in costs is different for increases in activity compared to equivalent decreases in activity. In this case, costs are termed “sticky......” if the change is less when activity falls than when activity rises, whereas costs are termed “anti-sticky” if the change is more when activity falls than when activity rises. Understanding such cost behavior is especially relevant for decision-makers and financial analysts that rely on accurate cost information...

  19. Influences of post weld heat treatment on fatigue crack growth behavior of TIG welding of 6013 T4 aluminum alloy joint (Part 1. Fatigue crack growth across the weld metal)

    Energy Technology Data Exchange (ETDEWEB)

    Haryadi, Gunawan Dwi; Kim, Seon Jin [Pukyong National University, Busan (Korea, Republic of)

    2011-09-15

    The present study evaluates the influences of PWHT on FCG behavior and tensile properties of TIG butt welded Al 6013-T4 sheets. Crack propagation tests were carried out on compact tension (CT) specimens. The T82 heat treatment was varied in three artificial aging times (soaking) of 6, 18 and 24 hours. The results of T82 heat treatment with artificial aging variations were tested for their fatigue crack growth rates at the main metal zone, the heat-affected zone (HAZ), and the welded metal zone. It has been observed that the various agings in heat treatment T82 are sensitive to the mechanical properties (fatigue crack growth rate test, tensile test). The results show that PWHT-T82 for 18 hours aging is the highest fatigue resistance, while the aging 18 hours provided the highest tensile test result.

  20. Magnetically frustrated behavior in multiferroics RMn2O5 (R =Bi, Eu, and Dy): A Raman scattering study

    Science.gov (United States)

    García-Flores, A. F.; Granado, E.; Martinho, H.; Rettori, C.; Golovenchits, E. I.; Sanina, V. A.; Oseroff, S. B.; Park, S.; Cheong, S.-W.

    2007-05-01

    A temperature dependent Raman scattering study in multiferroic single crystals RMn2O5 (R =Bi, Eu, and Dy) was performed. The Raman spectra were measured in the range from 150to450cm-1 involving mostly Mn-O-Mn bending vibrations, complementing our previous work in a higher frequency range involving Mn-O stretching modes. A number of studied phonons present anomalous frequency behavior below a characteristic temperature, T*˜60-65K, such as that found for the stretching modes. The sign and magnitude of such anomalous behavior appear to be correlated with the ionic radius of R, being softening for R =Bi and hardening for R =Eu and Dy in the range between TC/TN and T*. The anomalous phonon behaviors in both bending and stretching modes are consistent with an interpretation in terms of the spin-phonon coupling in a scenario of strong magnetic correlations.