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L Fischer,
J Klempnauer,
S Beckebaum,
H J Metselaar,
P Neuhaus,
P Schemmer,
U Settmacher,
N Heyne,
P-A Clavien,
F Muehlbacher, [......],
C Klein,
G Kazemier,
A Pascher, J Schmidt,
F Rauchfuss,
A Schnitzbauer,
S Nadalin,
M Hack,
S Ladenburger,
H J Schlitt
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ABSTRACT: Posttransplant immunosuppression with calcineurin inhibitors (CNIs) is associated with impaired renal function, while mTor inhibitors such as everolimus may provide a renal-sparing alternative. In this randomized 1-year study in patients with liver transplantation (LTx), we sought to assess the effects of everolimus on glomerular filtration rate (GFR) after conversion from CNIs compared to continued CNI treatment. Eligible study patients received basiliximab induction, CNI with/without corticosteroids for 4 weeks post-LTx, and were then randomized (if GFR > 50 mL/min) to continued CNIs (N = 102) or subsequent conversion to EVR (N = 101). Mean calculated GFR 11 months postrandomization (ITT population) revealed no significant difference between treatments using the Cockcroft-Gault formula (-2.9 mL/min in favor of EVR, 95%-CI: [-10.659; 4.814], p = 0.46), whereas use of the MDRD formula showed superiority for EVR (-7.8 mL/min, 95%-CI: [-14.366; -1.191], p = 0.021). Rates of mortality (EVR: 4.2% vs. CNI: 4.1%), biopsy-proven acute rejection (17.7% vs. 15.3%), and efficacy failure (20.8% vs. 20.4%) were similar. Infections, leukocytopenia, hyperlipidemia and treatment discontinuations occurred more frequently in the EVR group. No hepatic artery thrombosis and no excess of wound healing impairment were noted. Conversion from CNI-based to EVR-based immunosuppression proved to be a safe alternative post-LTx that deserves further investigation in terms of nephroprotection.
American Journal of Transplantation 04/2012; 12(7):1855-65. · 6.39 Impact Factor
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Journal of Animal Breeding and Genetics 04/2010; 36(1):55 - 100. · 1.46 Impact Factor
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O Stadel,
R Muydinov,
H Keune, J Schmidt,
A Blednov,
G Dosovitsky,
S Samoylenkov,
O Gorbenko,
A Kaul,
G Kotzyba,
R Nast,
W Goldacker
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ABSTRACT: In a reel to reel MOCVD system YBCO films and buffer layers were deposited on textured NiW-tapes. The layers of all RTR MOCVD Coated Conductors were grown with excellent in plane and out of plane texture with FWHM of 5-7° and 1.4-4° respectively. The critical current densities of these films were up to 1 MA/cm2 at 77 K. MOCVD-YBCO films on MOD CeO2/LZO buffered NiW (delivered by FZ Karlsruhe) could be coated with critical current densities of up to 2 MA/cm2. The 'End to End' critical current of MOCVD-YBCO on MOD-LZO/NiW (delivered by Nexans Superconductors) was 58 A for a 700 nm thick film onto a 10 mm wide tape.
Journal of Physics Conference Series 03/2008; 97(1):012158.
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physica status solidi (RRL) - Rapid Research Letters 08/2007; 1(6):235 - 237. · 2.22 Impact Factor
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D Post,
W Houlberg,
G Bateman,
L Bromberg,
D Cohn,
P Colestock,
M Hughes,
D Ignat,
R Izzo,
S Jardin, [......],
M Petravic,
M Phillips,
N Pomphrey, J Schmidt,
D Strickler,
A Todd,
N Uckan,
R White,
S Wolfe,
K Young
[show abstract]
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ABSTRACT: The Compact Ignition Tokamak (CIT) is a proposed modest-size ignition experiment designed to study the physics of alpha particle heating. The basic concept is to achieve ignition in a modest-size minimum cost experiment by using a high plasma density to achieve nτE ~ 2 × 1020s/m3 required for ignition. The high density requires a high toroidal field (10 T). The high toroidal field allows a large plasma current (10 MA) which provides a high level of ohmic heating, improves the energy confinement, and allows a relatively high beta (~ 6%). The present CIT design also has a high degree of elongation (κ ~ 1.8) to aid in producing the large plasma current. A double null poloidal divertor and pellet injection are part of the design to provide impurity and particle control, improve the confinement, and provide flexibility for improving the plasma profiles. Auxiliary heating is expected to be necessary to achieve ignition, and 10-20 MW of ICRF is to be provided.
Physica Scripta 02/2007; 1987(T16):89. · 1.20 Impact Factor
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G. Sonia,
E. Richter,
R. Lossy,
M. Mai, J. Schmidt,
M. Weyers,
G. Tränkle,
A. Denker,
J. Opitz-Coutureau,
G. Pensl,
I. Brauer,
H. P. Strunk
[show abstract]
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ABSTRACT: AlGaN/GaN heterojunction field effect transistors (HFETs) have been irradiated with protons at 68 MeV and 2 MeV with fluences up to 1013 cm–2 in order to simulate operation in space. Hall effect measurements, dc characteristics and RF load pull measurements at 2 GHz do not reveal significant changes indicating the suitability of the transistors for reliable operation in space. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
physica status solidi (c) 05/2006; 3(6):2338 - 2341.
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Y-K M Peng,
P J Fogarty,
T W Burgess,
D J Strickler,
B E Nelson,
J Tsai,
C A Neumeyer,
R Bell,
C Kessel,
J Menard, [......],
E Fredrickson,
L Grisham, J Schmidt,
P Rutherford,
S Sabbagh,
A Field,
A Sykes,
I Cook,
O Mitarai,
Y Takase
[show abstract]
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ABSTRACT: Recent experiments (Synakowski et al 2004 Nucl. Fusion 43 1648, Lloyd et al 2004 Plasma Phys. Control. Fusion 46 B477) on the Spherical Tokamak (or Spherical Torus, ST) (Peng 2000 Phys. Plasmas 7 1681) have discovered robust plasma conditions, easing shaping, stability limits, energy confinement, self-driven current and sustainment. This progress has encouraged an update of the plasma conditions and engineering of a Component Test Facility (CTF), (Cheng 1998 Fusion Eng. Des. 38 219) which is a very valuable step in the development of practical fusion energy. The testing conditions in a CTF are characterized by high fusion neutron fluxes Γn ≈ 8.8 × 1013 n s−1 cm−2 ('wall loading' WL ≈ 2 MW m−2), over size-scale >105 cm2 and depth-scale >50 cm, delivering >3 accumulated displacement per atom per year ('neutron fluence' >0.3 MW yr−1 m−2) (Abdou et al 1999 Fusion Technol. 29 1). Such conditions are estimated to be achievable in a CTF with R0 = 1.2 m, A = 1.5, elongation ~3, Ip ~ 12 MA, BT ~ 2.5 T, producing a driven fusion burn using 47 MW of combined neutral beam and RF heating power. A design concept that allows straight-line access via remote handling to all activated fusion core components is developed and presented. The ST CTF will test the lifetime of single-turn, copper alloy centre leg for the toroidal field coil without an induction solenoid and neutron shielding and require physics data on solenoid-free plasma current initiation, ramp-up to and sustainment at multiple megaampere level. A systems code that combines the key required plasma and engineering science conditions of CTF has been prepared and utilized as part of this study. The results show high potential for a family of relatively low cost CTF devices to suit a range of fusion engineering and technology test missions.
Plasma Physics and Controlled Fusion 11/2005; 47(12B):B263. · 2.42 Impact Factor
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J. Arndt,
W. Decker,
H. Keune,
L. Klippe,
U. Krause,
C. Metz,
W. Nemetz,
K. Nubian,
A. Nürnberg,
M. Pulver,
S.V. Samoilenkov, J. Schmidt,
O. Stadel,
D. Stiens,
R. Stolle,
O.Y. Gorbenko,
A.R. Kaul,
I.E. Korsakov
Chemical Vapor Deposition 03/2004; 10(2):61 - 66. · 1.80 Impact Factor
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M. Ono,
M. Peng,
C. Kessel,
C. Neumeyer, J. Schmidt,
J. Chrzanowski,
D. Darrow,
L. Grisham,
P. Heitzenroeder,
T. Jarboe,
C. Jun,
S. Kaye,
J. Menard,
R. Raman,
T. Stevenson,
M. Viola,
J. Wilson,
R. Woolley,
I. Zatz
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ABSTRACT: A spherical torus (ST) fusion energy development path which is complementary to the proposed tokamak burning plasma experiments such as ITER is described. The ST strategy focuses on a compact component test facility (CTF) and high performance advanced regimes leading to more attractive Demo and power plant scale reactors. To provide the physical basis for the CTF an intermediate step needs to be taken, which we refer to as the 'next-step spherical torus' (NSST) device and which we examine in some detail herein. NSST is a 'performance extension' stage ST with a plasma current of 5–10 MA, R = 1.5 m, BT ≤ 2.6 T and the possibility of varying physical parameters. The mission of NSST is to (1) provide a sufficient physical basis for the design of a CTF; (2) explore advanced operating scenarios with high bootstrap current fraction and high performance which can be utilized by CTF, Demo, and power plants; and (3) contribute to the general science of high β toroidal plasmas. The NSST is designed to utilize a TFTR-like site to minimize the cost and time required for design and construction.
Nuclear Fusion 02/2004; 44(3):452. · 4.09 Impact Factor
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D. M. Hofmann,
H. Zhou,
D. R. Pfisterer,
H. Alves,
B. K. Meyer,
P. Baranov,
N. Romanov,
C. de Mello Donega,
A. Meijering,
S. Orinskii,
H. Blok, J. Schmidt
[show abstract]
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ABSTRACT: The chemical nature of donors unintentionally present in ZnO nanocrystals prepared by chemical methods has been studied by high frequency electron paramagnetic resonance and electron nuclear double resonance. The experiments show that H, which is present during the preparation process, and acts as a shallow donor in bulk ZnO, is located in the Zn(OH)2 shell covering the nanocrystals. We find that Li, probably in an interstitial position, is incorporated in the core of the nanocrystals. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
physica status solidi (c) 02/2004; 1(4):908 - 911.
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ABSTRACT: The design of extrusion lines deals with the extruder and the die as well as with the down stream equipment, especially the cooling section. This paper aids in the design of these three units, regarding different aspects. The scale-up of extruders by means of the model theory is demonstrated in its practical use with examples. Emphasis is laid on the design of series of single screw extruders with mixing-pins and of twin-screw extruders (scale-up). There the adequate selection of the necessary restrictions for the compilation of model laws is discussed in detail. This is an approach to the safe machine design on the basis of model theory.The present standard of the calculation of threedimensional flow patterns in extrusion dies by means of the finite-element-method (FEM) is shown in order to point out how design-aids for the die-designer are derived from these calculations. After a discussion of application-criteria for the FEM, examples will show possible ways of using FEM-results.For the shaping of Y-branches in twin-screw machines the FEM-results point to possible plate-out areas and to their avoidance by geometrical modifications. The calculation of a die for a T-profile helps to design the passages between entry and exit sections. Finally, flow coefficients for the calculation of pressure losses in different cross sections are given.The design and optimization of cooling sections, as it can be done with the aid of the actual cooling models, is shown for some important extrusion processes. Heat transfer coefficients for practical cases (film-sheet-, pipe- and parison extrusion) are presented. Examples show, how diagrams for the design and optimization of cooling sections (for example the reduction of internal stresses and warping) can be made, using a microcomputer.
Advances in Polymer Technology 03/2003; 2(2):75 - 106. · 0.88 Impact Factor
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ABSTRACT: Deuterium-labelled brassinosteroids, namely [26,28-2H6]castasterone, 8, and [26,28-2H6]brassinolide, 9, were synthesized starting from 6,6- ethylenedioxy-20-formyl-2α,3α-isopropylidenedioxy-5α-pregnane, 1, and 3-[2H3]methyl-but-1-yne-[4,4,4-2H3], 11. Upon alkylating cleavage of the epoxide 6 with trimethylaluminium-n-butyllithium an unusual migration of a neighbouring [2H3]methyl group takes place to afford deuteriation at positions 26 and 28. Copyright © 2002 John Wiley & Sons, Ltd.
Journal of Labelled Compounds 01/2003; 46(3):231 - 242.
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ABSTRACT: Vinblastine and vincristine are two medically important bisindole alkaloids from Catharanthus roseus (Madagascar periwinkle). Attempts at production in cell cultures failed because a part of the complex pathway was not active, i.e. from tabersonine to vindoline. It starts with tabersonine 16-hydroxylase (T16H), a cytochrome P450-dependent enzyme. We now show that T16H is induced in the suspension culture by light and we report the cloning of the cDNA. The enzyme was expressed in Escherichia coli as translational fusion with the P450 reductase from C. roseus, and the reaction product was identified by mass spectrometry. The protein (CYP71D12) shares 47-52% identity with other members of the CYP71D subfamily with unknown function. The induction by light was strongly enhanced by a nutritional downshift (transfer into 8% aqueous sucrose). We discuss the possibility that the entire pathway to bisindoles can be expressed in suspension cultures.
FEBS Letters 10/1999; 458(2):97-102. · 3.54 Impact Factor
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J Schröder,
S Raiber,
T Berger,
A Schmidt, J Schmidt,
A M Soares-Sello,
E Bardshiri,
D Strack,
T J Simpson,
M Veit,
G Schröder
[show abstract]
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ABSTRACT: Heterologous screening of a cDNA library from Pinusstrobus seedlings identified clones for two chalcone synthase (CHS) related proteins (PStrCHS1 and PStrCHS2, 87.6% identity). Heterologous expression in Escherichia coli showed that PStrCHS1 performed the typical CHS reaction, that it used starter CoA-esters from the phenylpropanoid pathway, and that it performed three condensation reactions with malonyl-CoA, followed by the ring closure to the chalcone. PstrCHS2 was completely inactive with these starters and also with linear CoA-esters. Activity was detected only with a diketide derivative (N-acetylcysteamine thioester of 3-oxo-5-phenylpent-4-enoic acid) that corresponded to the CHS reaction intermediate postulated after the first condensation reaction. PstrCHS2 performed only one condensation, with 6-styryl-4-hydroxy-2-pyrone derivatives as release products. The enzyme preferred methylmalonyl-CoA against malonyl-CoA, if only methylmalonyl-CoA was available. These properties and a comparison with the CHS from Pinus sylvestris suggested for PstrCHS2 a special function in the biosynthesis of secondary products. In contrast to P. sylvestris, P. strobus contains C-methylated chalcone derivatives, and the methyl group is at the position predicted from a chain extension with methylmalonyl-CoA in the second condensation of the biosynthetic reaction sequence. We propose that PstrCHS2 specifically contributes the condensing reaction with methylmalonyl-CoA to yield a methylated triketide intermediate. We discuss a model that the biosynthesis of C-methylated chalcones represents the simplest example of a modular polyketide synthase.
Biochemistry 07/1998; 37(23):8417-25. · 3.42 Impact Factor
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J. Schröder,
S. Raiber,
T. Berger,
A. Schmidt, J. Schmidt,
A.M. Soares-Sello,
E. Bardshiri,
D. Strack,
T.J. Simpson,
M. Veit,
G. Schröder
[show abstract]
[hide abstract]
ABSTRACT: Heterologous screening of a cDNA library from Pinus strobus seedlings identified clones for two chalcone synthase (CHS) related proteins (PStrCHS1 and PStrCHS2, 87.6% identity). Heterologous expression in Escherichia coli showed that PStrCHS1 performed the typical CHS reaction, that it used starter CoA- esters from the phenylpropanoid pathway, and that it performed three condensation reactions with malonyl-CoA, followed by the ring closure to the chalcone. PstrCHS2 was completely inactive with these starters and also with linear CoA-esters. Activity was detected only with a diketide derivative (N-acetylcysteamine thioester of 3-oxo-5-phenylpent-4-enoic acid) that corresponded to the CHS reaction intermediate postulated after the first condensation reaction. PstrCHS2 performed only one condensation, with 6-styryl-4-hydroxy-2-pyrone derivatives as release products. The enzyme preferred methylmalonyl-CoA against malonyl-CoA, if only methylmalonyl-CoA was available. These properties and a comparison with the CHS from Pinus sylvestris suggested for PstrCHS2 a special function in the biosynthesis of secondary products. In contrast to P. sylvestris, P. strobus contains C- methylated chalcone derivatives, and the methyl group is at the position predicted from a chain extension with methylmalonyl-CoA in the second condensation of the biosynthetic reaction sequence. We propose that PstrCHS2 specifically contributes the condensing reaction with methylmalonyl-CoA to yield a methylated triketide intermediate. We discuss a model that the biosynthesis of C- methylated chalcones represents the simplest example of a modular polyketide synthase.
Biochemistry. 01/1998; 37:8417-8425.
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ABSTRACT: The One-Dimensional non-steady-state Six-Layer SVAT model (SLODSVAT) was applied to a quasihomogeneous stand of spruce trees (Picea abies [L.] Karst) in the Solling hills (Germany) in order to describe the water transport from the soil into the atmosphere through the roots-stem-shoots-needles system of the trees and to predict the possible response to changes of soil water conditions on transpiration rate of the forest. The modelled water uptake and evapotranspiration rates were compared with long-term sap flow, eddy correlation and gradient flux measurements for a one-week test period (01-08.07.1995) which provided a variety of weather conditions including clear as well as partly cloudy and rainy days. Moreover, for this period the sensitivity of response of the transpiration rate and water uptake to changes of environmental conditions is estimated. The results show, that the SLODSVAT can describe and simulate the short-term variability of water uptake by the roots and evapotranspiration in the spruce forest adequately under different environmental conditions. For the selected period the SLODSVAT explained about 94% of the variation of water uptake (r2=0.940), and 88% and 78% of variation of evapotranspiration measured by Bowen ratio - energy balance (r2=0.881) and eddy correlation (r2=0.785) methods, respectively. Thus, these results give evidence that it is possible to estimate and predict evapotranspiration and transpiration rates for spruce forest ecosystems in the stand-scale during one vegetation period if appropriate input parameters for the soil and canopy structure and the atmospheric conditions are available.
Physics and Chemistry of the Earth Parts A/B/C 02/1996; 21(3):195-199. · 1.11 Impact Factor
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R. Goldston,
G. Bateman,
M. Bell,
P. Colestock,
S. Jardin,
S. Medley,
R. Perkins,
N. Pomphrey, J. Schmidt,
D. Stotler,
M. Ulrickson,
K. Young,
R. Bickerton,
E. Chaniotakis,
D. Cohn,
M. Porkolab,
D. Sigmar,
D. Hill,
Hou
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ABSTRACT: The mission of the CIT device is to determine the physics behavior of self-heated fusion plasmas, and to demonstrate the production of substantial amounts of fusion power. In order to achieve this mission at minimum risk and cost, CIT is designed to be a high field, compact, copper-coil device, of modest pulse length. The best measure of extrapolation in confinement properties is the dimensionless parameter {omega}{sub c}{tau}{sub E}. CIT is projected to stand midway between JET and ITER in this parameter, and so represents a relatively modest step. Nonetheless, because nT{tau}{sub E} {alpha} B for dimensionlessly similar devices (aB{sup 4/5} = const.). CIT should have about the same nT{tau}{sub E} as ITER, {minus}10x that of JET. Standard assumptions on confinement, impurity levels, and profile shapes project to Q = 25, with 20 MW of heating power, corresponding to {beta} = 3% (=21/aB) and a total fusion output power of 500 MW. Even given pessimistic projection assumptions. CIT can achieve its basic mission to determine the confinement physics, operational limits, and {alpha}-particle dynamics of self-heated fusion plasmas with {alpha} power greater than auxiliary heating power, while producing more than 100 MW of fusion power. In order to reach these conditions CIT will also demonstrate heating, fueling, and plasma handling techniques necessary to produce reactorlike power density, self-heated fusion plasmas. 3 refs., 3 figs.
12/1989
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R. Parker,
D.B. Montgomery,
R. Myer,
R. Pillsbury,
M. Porkolab,
D. Sigmar,
R. Thome,
G. Bateman,
P. Colestock,
H. Furth, [......],
J. Manickam,
C.K. Phillips,
N. Pomphrey,
D.E. Post,
P. Rutherford, J. Schmidt,
G. Sheffield,
D. Stotler,
W. Houlberg,
Say
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ABSTRACT: The CIT is a high-field, compact tokamak design whose objective is the study of physics issues associated with burning plasmas. The toroidal and poloidal field coils employ a copper-steel laminate, manufactured by explosive-bonding techniques, to support the forces generated by the design fields: 10 T toroidal field at the plasma center, and 21 T in the OH solenoid. A combination of internal and external PF coils provide control of the equilibrium and the ability to sweep the magnetic separatrix across the divertor plates during a pulse. At temperatures and {beta}{sub {alpha}} levels characteristic of ITER designs, the fusion power in CIT approaches 800 MW and can be the limiting factor in the pulse length. Ignition requires that the confinement time exceed present L-mode scalings by about a factor-of-two, which is anticipated to occur as a result of the operational flexibility incorporated into the design. Conventional operating limits given by {r angle}{beta}{l angle} < 3I/aB, {bar n}{sub 20} < 2B/Rq{sub e} and q{sub {Psi}} {le} 3.2 have been chosen and, in the case of MHD limits, have been justified by ideal stability analysis. The power required for CIT ignition ranges from 10 MW to 40 MW or more, depending on confinement assumptions, and either ICRF or ECRF heating, or both, will be used. 12 refs., 6 figs.
12/1987
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ABSTRACT: The development/modification and qualification of welding technology for generating compressive stresses in austenitic stainless steel piping welds are discussed. The following welding processes are considered:1.A modified, orbital gas tungsten arc (GTA) narrow-gap welding process with significant improvements over conventional and standard narrow-gap orbital pipe welding,2.The heat sink welding (HSW) process with internal cooling of the pipe with water or liquefied CO2 gas, and3.The postwelding process. Last pass heat sink welding (LPHSW) for altering residual stresses in an existing weld.Residual stresses have been measured by using the so-called ring-core as well as radiographic procedures. In support of experimental work required to qualify these welding techniques a numerical simulation effort was undertaken.
Nuclear Engineering and Design.
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ABSTRACT: In the past, weld-induced residual stresses caused damage to numerous (power) plant parts, components and systems (Erve, M., Wesseling, U., Kilian, R., Hardt, R., Brümmer, G., Maier, V., Ilg, U., 1994. Cracking in Stabilized Austenitic Stainless Steel Piping of German Boiling Water Reactors — Characteristic Features and Root Causes. 20. MPA-Seminar 1994, vol. 2, paper 29, pp.29.1–29.21). In the case of BWR nuclear power plants, this damage can be caused by the mechanism of intergranular stress corrosion cracking in austenitic piping or the core shroud in the reactor pressure vessel and is triggered chiefly by weld-induced residual stresses. One solution of this problem that has been used in the past involves experimental measurements of residual stresses in conjunction with weld optimization testing. However, the experimental analysis of all relevant parameters is an extremely tedious process. Numerical simulation using the finite element method (FEM) not only supplements this method but, in view of modern computer capacities, is also an equally valid alternative in its own right. This paper will demonstrate that the technique developed for numerical simulation of the welding process has not only been properly verified and validated on austenitic pipe welds, but that it also permits making selective statements on improvements to the welding process. For instance, numerical simulation can provide information on the starting point of welding for every weld bead, the effect of interpass cooling as far as a possible sensitization of the heat affected zone (HAZ) is concerned, the effect of gap width on the resultant weld residual stresses, or the effect of the ‘last pass heat sink welding’ (welding of the final passes while simultaneously cooling the inner surface with water) producing compressive stresses in the root area of a circumferential weld in an austenitic pipe. The computer program feresa (finite element residual stress analysis) was based on a commercially available abaqus code (Hibbitt, Karlsson, Sorensen, Inc, 1997. abaqus user's manual, version 5.6), and can be used as a 2-D or 3-D FEM analysis; depending on task definition it can provide a starting point for a fracture mechanics safety analysis with acceptable computing times.
Nuclear Engineering and Design.
