Peening as a stress relieving method for welded joints

International Nuclear Information System (INIS)

Ferreira, M.L.R.

1984-01-01

The efficacy of the process of stress relieving by hammer-peening, in heavy plates of low carbon steel is analysed. The effects of peening in the mechanical properties of welded metal deposited by shield metal arc welding, using the electrodes E-6010, E-7018 and E-8018C-2, and the weld metal deposited by submerged arc welding, using the filler metals ENil and EA3, are also analysed. X-ray diffraction was used in order to verify the efficacy of peening as a stress-relieving process. The obtained results and the literature reviewed show that, peening is effective in stress relieving. (author) [pt

The Effect of Multiple Shot Peening on the Corrosion Behavior of Duplex Stainless Steel

Science.gov (United States)

Feng, Qiang; She, Jia; Wu, Xueyan; Wang, Chengxi; Jiang, Chuanhai

2018-03-01

Various types of shot peening treatments were applied to duplex stainless steel. The effects of shot peening intensity and working procedures on the microstructure were investigated. The domain size and microstrain evolution in the surface layer were characterized utilizing the Rietveld method. As the shot peening intensity increased, the surface roughness increased in the surface layer; however, it decreased after multiple (dual and triple) shot peening. The mole fraction of strain-induced martensite as a function of the intensity of shot peening was evaluated by XRD measurements. Both potentiodynamic polarization curves and salt spray tests of shot-peened samples in NaCl solution were investigated. The results indicate that traditional shot peening has negative effects on corrosion resistance with increasing shot peening intensity; however, the corrosion rate can be reduced by means of multiple shot peening.

An investigation of the properties of conventional and severe shot peened low alloy steel

Science.gov (United States)

Quang Trung, Pham; Butler, David Lee; Win Khun, Nay

2017-07-01

The effects of the conventional shot peening and severe shot peening process on the mechanical and tribological properties of shot peened AISI 4340 high strength steel were systematically investigated. Compared with the conventional shot peened sample, the ultrafine grain surface layer with a depth of about 20 µm generated by the severe shot peening process can enhance the hardness and wear resistance of the treated material. However, deeper dimples generated by the high media velocity in the severe shot peening process resulted in a higher surface roughness, which is considered as a side effect of this method reducing the fatigue life of the material. Applying a smaller shot size with an appropriate intensity can be used to peen the severe shot peened samples to not only reduce the surface roughness and friction coefficient but also improve the wear resistance for these samples. This work was presented in the shot peening section during ‘The 30th International Conference on Surface Modification Technologies, 2016, Milan, Italy’ (SMT30, ID 61, entitled ‘Comparison of the effects of conventional shot peening and severe shot peening processes on the mechanical and tribological properties of shot peened AISI 4340’) and the authors were encouraged to submit a manuscript to the Materials Research Express journal after adding some nessesary information.

Laser Peening Of Components Of Thin Cross-Section

Science.gov (United States)

Hackel, Lloyd A.; Halpin, John M.; Harris, Jr., Fritz B.

2004-10-19

The properties of a metal piece are altered by laser peening the piece on the first side using an acoustic coupling material operatively connected to the second side and subsequently laser peening the piece on the second side using an acoustic coupling material operatively connected to the first side.

External glass peening of zircaloy calandria tubes to increase the critical heat flux

International Nuclear Information System (INIS)

Fong, R.W.L.; Coleman, C.E.; Nitheanandan, T.; Kroeger, V.D.; Moyer, R.G.; Sanderson, D.B.; Root, J.H.; Rogge, R.B.

1997-12-01

Glass-peening the outside surfaces of Zircaloy calandria tubes increases the nucleation sites available for boiling heat transfer and has been demonstrated to enhance the critical heat flux (CHF) in pool-boiling experiments. The objective of this study is to optimise the heat-transfer enhancement by glass peening while ensuring that the microstructure of the peened tube is acceptable for reactor use. Pool-boiling tests were done using small Zircaloy tubes with as-received ('smooth') surfaces and variously peened surfaces, to evaluate two peening parameters, glass-bead size and the coverage of peened surface. Our results showed that the maximum enhancement of CHF (by 60% compared with as-received tubes) was obtained using a glass-bead size of 90-125 μm with a coverage of 100%. The CHF enhancement was found to be insensitive to glass-bead size over a wide range (from 60-90 μm to 125-180 μm). Using a fixed glass-bead size of 125-180 μm to evaluate the influence of peening coverage, the maximum effect on the CHF response was obtained with a coverage of 1 00%. The microstructures of the peened tubes were evaluated using light microscopy, X-ray and neutron diffraction, and mechanical tests. After peening, the microstructure in the subsurface layer (-30 μm) consisted of deformed α-Zr grains, and the crystallographic texture of the grains changed slightly. After stress-relieving at 500 degrees C for 1 h, some recrystallisation had occurred and the residual strains remaining in the tube were low. The tensile and burst properties of glass-peened and stress-relieved tubes were similar to those of as-received tubes. The microstructures introduced by peening and stress relieving were judged to have little effect on creep and growth behaviour. Since there are no deleterious consequences of the glass-peening treatment, the peened and stress-relieved tubes are found to be acceptable for reactor use. (author)

The Numerical FEM Model of the Kinematics of the Vibratory Shot Peening Process

Directory of Open Access Journals (Sweden)

Stanisław Bławucki

2017-12-01

Full Text Available The paper presents the results of numerical calculations, with the finite element method in the ABAQUS program environment, of the vibratory shot peening process with loose peening elements. The behaviour of shot peening elements was analysed in the kinematic aspect. The impact of the initial deployment of vibratory shot peening elements on their behaviour during processing was investigated, including the displacement, velocity, acceleration and the number of collisions. The way of determining the effectiveness of the processing with the vibratory shot peening was illustrated.

Effect of laser peening with glycerol as plasma confinement layer

Science.gov (United States)

Tsuyama, Miho; Ehara, Naoya; Yamashita, Kazuma; Heya, Manabu; Nakano, Hitoshi

2018-03-01

The effects of controlling the plasma confinement layer on laser peening were investigated by measuring the hardness and residual stress of laser-peened stainless steels. The plasma confinement layer contributes to increasing the pressure of shock waves by suppressing the expansion of the laser-produced plasma. Most previous studies on laser peening have employed water as the plasma confinement layer. In this study, a glycerol solution is used in the context of a large acoustic impedance. It is found that this glycerol solution is superior to water in its ability to confine plasma and that suitable conditions exist for the glycerol solution to act as a plasma confinement layer to achieve efficient laser peening.

Residual stress evaluation and curvature behavior of aluminum 7050 peen forming processed; Avaliacao da tensao residual em aluminio 7050 conformado pelo processo peen forming

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Rene Ramos de

2011-07-01

Shot peening is a superficial cold work process used to increase the fatigue life evaluated by residual stress measurements. The peen forming process is a variant of the shot peening process, where a curvature in the plate is obtained by the compression of the grains near to the surface. In this paper, the influence of the parameters such as: pressure of shot, ball shot size and thickness of aluminum 7050 samples with respect to residual stress profile and resulting arc height was studied. The evaluation of the residual stress profile was obtained by sin{sup 2} {psi} method. The results show that the formation of the curvature arc height is proportional to the shot peening pressure, of spheres size and inversely proportional to the thickness of the sample, and that stress concentration factor is larger for samples shot peened with small balls. On final of this paper presents an additional study on micro strain and average crystallite size, which can evaluate the profile of the samples after blasting. (author)

The wear and corrosion resistance of shot peened-nitrided 316L austenitic stainless steel

International Nuclear Information System (INIS)

Hashemi, B.; Rezaee Yazdi, M.; Azar, V.

2011-01-01

Research highlights: → Shot peening-nitriding increased the wear resistance and surface hardness of samples. → This treatment improved the surface mechanical properties. → Shot peening alleviates the adverse effects of nitriding on the corrosion behavior. -- Abstract: 316L austenitic stainless steel was gas nitrided at 570 o C with pre-shot peening. Shot peening and nitriding are surface treatments that enhance the mechanical properties of surface layers by inducing compressive residual stresses and formation of hard phases, respectively. The structural phases, micro-hardness, wear behavior and corrosion resistance of specimens were investigated by X-ray diffraction, Vickers micro-hardness, wear testing, scanning electron microscopy and cyclic polarization tests. The effects of shot peening on the nitride layer formation and corrosion resistance of specimens were studied. The results showed that shot peening enhanced the nitride layer formation. The shot peened-nitrided specimens had higher wear resistance and hardness than other specimens. On the other hand, although nitriding deteriorated the corrosion resistance of the specimens, cyclic polarization tests showed that shot peening before the nitriding treatment could alleviate this adverse effect.

Investigation on un-peened and laser shock peened weldment of Inconel 600 fabricated by ATIG welding process

Energy Technology Data Exchange (ETDEWEB)

Chandrasekar, G., E-mail: gopalsamychandrasekar@gmail.com [Department of Mechanical Engineering, PSNA College of Engineering and Technology, Dindigul 624622, Tamilnadu (India); Kailasanathan, C., E-mail: uthrakailash@yahoo.co.in [Department of Mechanical Engineering, Sethu Institute of Technology, Virudhunagar District, Kariapatti 626115, Tamilnadu (India); Verma, Dhanesh Kant, E-mail: dkverma@bheltry.co.in [Welding Research Institute, Bharat Heavy Electricals Limited, Thiruchirappalli 620014, Tamilnadu (India)

2017-04-06

The present investigation articulates the joining of Inconel 600 plates using activated tungsten inert gas (ATIG) welding process. Before joining of Inconel 600 plates, welding parameters have been optimized and suitable flux has been selected to produce complete weld penetration in a single pass welding. The various mechanical and metallurgical characterizations were performed on the un-peened ATIG (UP-ATIG) weldment. The experimental results attested that the tensile failure occurred in the weld zone and also the tensile strength is lower than the base metal (BM) because of coarser grain structures and tensile residual stresses in the weld zone. Laser shock peening (LSP) was carried out on the welded joint to enhance its properties. After LSP treatment, the significant improvement was observed in the laser peened ATIG (LP-ATIG) weldment and the fracture occurred at the parent metal side owing to the compressive residual stresses developed by LSP. Residual stress measurements indicated that the compressive residual stresses were higher at the surface and they decrease with increasing depth.

Investigation on un-peened and laser shock peened weldment of Inconel 600 fabricated by ATIG welding process

International Nuclear Information System (INIS)

Chandrasekar, G.; Kailasanathan, C.; Verma, Dhanesh Kant

2017-01-01

The present investigation articulates the joining of Inconel 600 plates using activated tungsten inert gas (ATIG) welding process. Before joining of Inconel 600 plates, welding parameters have been optimized and suitable flux has been selected to produce complete weld penetration in a single pass welding. The various mechanical and metallurgical characterizations were performed on the un-peened ATIG (UP-ATIG) weldment. The experimental results attested that the tensile failure occurred in the weld zone and also the tensile strength is lower than the base metal (BM) because of coarser grain structures and tensile residual stresses in the weld zone. Laser shock peening (LSP) was carried out on the welded joint to enhance its properties. After LSP treatment, the significant improvement was observed in the laser peened ATIG (LP-ATIG) weldment and the fracture occurred at the parent metal side owing to the compressive residual stresses developed by LSP. Residual stress measurements indicated that the compressive residual stresses were higher at the surface and they decrease with increasing depth.

Shot-peening of carbonitrided steel: influence of the process on the mechanical state

Directory of Open Access Journals (Sweden)

François M.

2010-06-01

Full Text Available Residual stresses have a significant role in affecting engineering properties of materials and shot peening process is an effective production technique to ensure required residual stress levels. This paper presents an analysis of an orthogonal design of experiment to establish an empirical relationship between main parameters of shot peening process and residual stress profiles for a carbonitrided steel. The hardening / softening evolution of the material is followed using hardness and diffraction peak width. Four critical peening parameters, i.e. shot size, incident angle, exposure time, airblast pressure, have been chosen and the range of peening conditions are established by using the Taguchi technique. In this study, a shot velocity measurement system is used to obtain the on-line velocity during the peening process and the relationship between the maximum compressive residual stresses and the shot velocity is also developed. Analysis of the experimental data showed that it is possible to optimize the shot peening process by an effective control of process parameters.

Residual stress evaluation and curvature behavior of aluminium 7050 peen forming processed; Avaliacao da tensao residual em aluminio 7050 conformado pelo processo peen forming

Energy Technology Data Exchange (ETDEWEB)

Oliveira, R.R. de; Lima, N.B., E-mail: rolivier@ipen.b, E-mail: nblima@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Braga, A.P.V.; Goncalves, M., E-mail: anapaola@ipt.b, E-mail: mgoncalves@ipt.b [Instituto de Pesquisas Tecnologicas (IPT), Sao Paulo, SP (Brazil)

2010-07-01

Shot peening is a superficial cold work process used to increase the fatigue life evaluated by residual stress measurements. The peen forming process is a variant of the shot peening process, where a curvature in the plate is obtained by the compression of the grains near to the surface. In this paper, the influence of the parameters such as: pressure of shot, ball shot size and thickness of aluminum 7050 samples with respect to residual stress profile and resulting arc height was studied. The evaluation of the residual stress profile was obtained by sin{sup 2} {Psi} method. (author)

Effect of shot peening on metastable austenitic stainless steels

Energy Technology Data Exchange (ETDEWEB)

Fargas, G., E-mail: gemma.fargas@upc.edu [CIEFMA - Departament de Ciència dels Materials i Enginyeria Metallúrgica, Universitat Politècnica de Catalunya, 08028 Barcelona (Spain); CRnE, Centre de Recerca en Nanoenginyeria, Universitat Politècnica de Catalunya, 08028 Barcelona (Spain); Roa, J.J.; Mateo, A. [CIEFMA - Departament de Ciència dels Materials i Enginyeria Metallúrgica, Universitat Politècnica de Catalunya, 08028 Barcelona (Spain); CRnE, Centre de Recerca en Nanoenginyeria, Universitat Politècnica de Catalunya, 08028 Barcelona (Spain)

2015-08-12

In this work, shot peening was performed in a metastable austenitic stainless steel EN 1.4318 (AISI 301LN) in order to evaluate its effect on austenite to martensite phase transformation and also the influence on the fatigue limit. Two different steel conditions were considered: annealed, i.e., with a fully austenitic microstructure, and cold rolled, consisting of a mixture of austenite and martensite. X-ray diffraction, electron back-scattered diffraction and focus ion beam, as well as nanoindentation techniques, were used to elucidate deformation mechanisms activated during shot peening and correlate with fatigue response. Results pointed out that extensive plastic deformation and phase transformation developed in annealed specimens as a consequence of shot peening. However, the increase of roughness and the generation of microcracks led to a limited fatigue limit improvement. In contrast, shot peened cold rolled specimens exhibited enhanced fatigue limit. In the latter case, the main factor that determined the influence on the fatigue response was the distance from the injector, followed successively by the exit speed of the shots and the coverage factor.

A study on corrosive behavior of spring steel by shot-peening process

International Nuclear Information System (INIS)

An, Jae Pil; Park, Keyung Dong

2004-01-01

In this study, the influence of shot peening on the corrosion was investigated on spring steel immersed in 3.5% NaCl. The immersion test was performed on the two kinds of specimens. Corrosion potential, polarization curve, residual stress and etc. were investigated from experimental results. From test results, the effect of shot peening on the corrosion was evaluated. In case of corrosion potential, shot peened specimen shows more activated negative direction as compared with parent metal. Surface of specimen, which is treated with the shot peened, is placed as more activated state against inner base metal. It can cause the anti-corrosion effect on the base metal

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

International Nuclear Information System (INIS)

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

2014-01-01

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

Surface layer investigation of duplex stainless steel S32205 after stress peening utilizing X-ray diffraction

International Nuclear Information System (INIS)

Feng, Qiang; Jiang, Chuanhai; Xu, Zhou

2013-01-01

Highlights: ► The stress shot peening is superior to the conventional shot peening. ► Residual stresses along the loaded direction are bigger than transverse direction. ► Higher prestress leads to smaller domain size, high density of dislocation. ► Compared to ferrite, austenite has much higher hardness and work hardening. ► Ferrite has higher recover of elastic deformation than austenite after unloading. - Abstract: Residual stresses and micro-hardness of duplex stainless steel S32205 after stress peening are measured and domain sizes and microstrain are calculated. The results show that stress peening can significantly improve the compressive residual stresses and micro-hardness in both austenite and ferrite, and the former is affected by both the prestress and the measurement directions. Microstructure investigation reveals that material deformation is enhanced after stress peening, and smaller domain sizes and higher microstrain are introduced. The compressive residual stress enhancement by stress peening in ferrite is more than that in austenite under the same stress peening, which is due to the more elastic deformation recover in ferrite. Therefore, the difference of residual stresses between ferrite and austenite can be narrowed down by conducting appropriate stress peening. Based on these investigations, it is concluded that stress peening is superior to conventional shot peening treatment to improve the surface properties of duplex stainless steel

IMPACT OF VIBRATORY AND ROTATIONAL SHOT PEENING ONTO SELECTED PROPERTIES OF TITANIUM ALLOY SURFACE LAYER

Directory of Open Access Journals (Sweden)

Kazimierz Zaleski

2014-06-01

Full Text Available This study presents the results of tests on impact of vibratory and rotational shot peening of the Ti6A12Mo2Cr titanium alloy onto the processed object surface roughness and surface layer microhardness. The external surfaces of ring-shaped samples were shot peened. The preceding process consisted of turning with a cubic boron nitride blade knife. Steel beads, having a diameter of 6 mm, were used as a processing medium. The variable parameters of shot peening were vibrator amplitude and shot peening time. The range of recommended technological parameters for vibratory and rotational shot peening was determined. As a result of shot peening, the surface roughness could be reduced by approximately 4 times and the surface layer could be hardened to the depth of approximately 0.4 mm.

Evaluation the Mechanical Properties of Shot Peened TIG Welded Aluminum Sheets

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Ahmed Ameed Zain Al-Abideen

2017-04-01

Full Text Available A tungsten inert gas (TIG welding is one of the most popular kinds of welding used to join metals mainly for aluminum alloys. However, many challenges may be met with this kind of joining process; these challenges arise from decay of mechanical properties of welded materials. In the present study, an attempt was made to enhancing the mechanical properties of TIG weld joint of 6061-T6 aluminum alloy by hardening the surfaces using shoot peening technique. To optimize the shoot peening process three times of exposure (5, 10, and 15 min. was used. All peened and unpeened, and welded and unwelded samples were characterized by metallographic test to indicate the phase transformation and modification in microstructure occurring during welding process. Tensile test and Vickers micro-hardness measurements were performed for all samples to investigate the effect of shoot peening on mechanical properties of welded aluminum. The results indicated a significant improvement in properties for peened welded and unwelded samples compared with those unpeened one. Also, the results showed that the tensile and microhardness properties were increased with increasing the time of exposure to 15 min. due to generation of compressive residual stresses at surface.

Numerical simulation of the shot peening process under previous loading conditions

International Nuclear Information System (INIS)

Romero-Ángeles, B; Urriolagoitia-Sosa, G; Torres-San Miguel, C R; Molina-Ballinas, A; Benítez-García, H A; Vargas-Bustos, J A; Urriolagoitia-Calderón, G

2015-01-01

This research presents a numerical simulation of the shot peening process and determines the residual stress field induced into a component with a previous loading history. The importance of this analysis is based on the fact that mechanical elements under shot peening are also subjected to manufacturing processes, which convert raw material into finished product. However, material is not provided in a virgin state, it has a previous loading history caused by the manner it is fabricated. This condition could alter some beneficial aspects of the residual stress induced by shot peening and could accelerate the crack nucleation and propagation progression. Studies were performed in beams subjected to strain hardening in tension (5ε y ) before shot peening was applied. Latter results were then compared in a numerical assessment of an induced residual stress field by shot peening carried out in a component (beam) without any previous loading history. In this paper, it is clearly shown the detrimental or beneficial effect that previous loading history can bring to the mechanical component and how it can be controlled to improve the mechanical behavior of the material

Laser Shot Peening System Final Report CRADA No. TC-1369-96

Energy Technology Data Exchange (ETDEWEB)

Stuart, B. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Harris, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-09-27

This CRADA project was established with a primary goal to develop a laser shot peening system which could operate at production throughput rates and produce the desired depth and intensity of induced shots. The first objective was to understand all parameters required for acceptable peening, including pulse energy, pulse temporal format, pulse spatial format, sample configuration and tamping mechanism. The next objective was to demonstrate the technique on representative samples and then on representative parts. The final objective was to implement the technology into a meaningful industrial peen.

Residual stress evaluation and curvature behavior of aluminum 7050 peen forming processed

International Nuclear Information System (INIS)

Oliveira, Rene Ramos de

2011-01-01

Shot peening is a superficial cold work process used to increase the fatigue life evaluated by residual stress measurements. The peen forming process is a variant of the shot peening process, where a curvature in the plate is obtained by the compression of the grains near to the surface. In this paper, the influence of the parameters such as: pressure of shot, ball shot size and thickness of aluminum 7050 samples with respect to residual stress profile and resulting arc height was studied. The evaluation of the residual stress profile was obtained by sin 2 ψ method. The results show that the formation of the curvature arc height is proportional to the shot peening pressure, of spheres size and inversely proportional to the thickness of the sample, and that stress concentration factor is larger for samples shot peened with small balls. On final of this paper presents an additional study on micro strain and average crystallite size, which can evaluate the profile of the samples after blasting. (author)

The effect of shot peening on notched low cycle fatigue

International Nuclear Information System (INIS)

Soady, K.A.; Mellor, B.G.; Shackleton, J.; Morris, A.; Reed, P.A.S.

2011-01-01

Highlights: → Shot peening improves notched component three point bend low cycle fatigue life. → Notch shape does not affect the efficacy of the peening process. → Strain hardening and residual stress effects need separate consideration. → Loading direction residual stresses do not relax under bend load. - Abstract: The improvement in low cycle fatigue life created by shot peening ferritic heat resistant steel was investigated in components of varying geometries based on those found in conventional power station steam turbine blades. It was found that the shape of the component did not affect the efficacy of the shot peening process, which was found to be beneficial even under the high stress amplitude three point bend loads applied. Furthermore, by varying the shot peening process parameters and considering fatigue life it has been shown that the three surface effects of shot peening; roughening, strain hardening and the generation of a compressive residual stress field must be included in remnant life models as physically separate entities. The compressive residual stress field during plane bending low cycle fatigue has been experimentally determined using X-ray diffraction at varying life fractions and found to be retained in a direction parallel to that of loading and to only relax to 80% of its original magnitude in a direction orthogonal to loading. This result, which contributes to the retention of fatigue life improvement in low cycle fatigue conditions, has been discussed in light of the specific stress distribution applied to the components. The ultimate aim of the research is to apply these results in a life assessment methodology which can be used to justify a reduction in the length of scheduled plant overhauls. This will result in significant cost savings for the generating utility.

Influence of the shot-peening treatment on the CRF gearing behaviour

International Nuclear Information System (INIS)

Molinie, D.; Lemaire, E.; Randrianarivo, L.; Dorier, C.

1998-01-01

Surface damage are observed in service on CRF case-hardened cases. Such damage is like surface fatigue which appears in the form of frosting and can come to a micro-spalling or even a spalling damage. Survey and studies realised on gears affected by such damage, led EDF and the manufacturer to search for appropriated solutions since 1985 (optimisation of the gear bottom profile, care of the grinding and the thermochemical processing, use of oils with higher viscosity). Simulations on a running wheel device can reproduce the meshing conditions on simplified specimen. The aim is to study the influence of residual stresses following a severe grinding and shot peening treatments. An empiric selection was realised among different shot peening treatments. Endurance tests are realised on case-hardened gears with or without shot-peening treatments. Compared with standard grinded gears, it appears that the shot-peening selected increases up to 40% the gear lifetime till extended spalling. (authors)

Feasibility of ultrasonic and eddy current methods for measurement of residual stress in shot peened metals

International Nuclear Information System (INIS)

Lavrentyev, Anton I.; Stucky, Paul A.; Veronesi, William A.

2000-01-01

Shot peening is a well-known method for extending the fatigue life of metal components by introducing compressive residual stresses near their surfaces. The capability to nondestructively evaluate the near surface residual stress would greatly aid the assurance of proper fatigue life in shot-peened components. This paper presents preliminary results from a feasibility study examining the use of ultrasonic and eddy current NDE methods for residual stress measurement in components where the stress has been introduced by shot peening. With an ultrasonic method, a variation of ultrasonic surface wave speed with shot peening intensity was measured. Near surface conductivity was measured by eddy current methods. Since the effective penetration depth of both methods employed is inversely related to the excitation frequency, by making measurements at different frequencies, each method has the potential to provide the stress-depth profile. Experiments were conducted on aluminum specimens (alloy 7075-T7351) peened within the Almen peening intensity range of 4C to 16C. The experimental results obtained demonstrate a correlation between peening intensity and Rayleigh wave velocity and between peening intensity and conductivity. The data suggests either of the methods may be suitable, with limitations, for detecting unsatisfactory levels of shot peening. Several factors were found to contribute to the measured responses: surface roughness, near surface plastic deformation (cold work) and residual stress. The contribution of each factor was studied experimentally. The feasibility of residual stress determination from the measured data is discussed

Microscopic analysis of effect of shot peening on corrosion fatigue behavior of aluminum alloy

International Nuclear Information System (INIS)

Kim, Jong Cheon; Cheong, Seong Kyun

2012-01-01

The object of this study considers corrosion fatigue improvement of 7075-T6 aluminum by using shot peening treatment on 3.5% NaCl solution at room temperature. Aluminum alloy is generally used in aerospace structural components because of the light weight and high strength characteristics. Many studies have shown that an aluminum alloy can be approximately 50% lighter than other materials. Mostly, corrosion leads to earlier fatigue crack propagation under tensile conditions and severely reduces the life of structures. Therefore, the technique to improve material resistance to corrosion fatigue is required. Shot peening technology is widely used to improve fatigue life and other mechanical properties by induced compressive residual stress. Even the roughness of treated surface causes pitting corrosion, the compressive residual stress, which is induced under the surface layer of material by shot peening, suppersses the corrosion and increases the corrosion resistance. The experimental results for shot peened specimens were compared with previous work for non treated aluminum alloy. The results show that the shot peening treatment affects the corrosion fatigue improvement of aluminum alloys and the induced compressive residual stress by shot peening treatment improves the resistance to corrosion fatigue

Microscopic analysis of effect of shot peening on corrosion fatigue behavior of aluminum alloy

Energy Technology Data Exchange (ETDEWEB)

Kim, Jong Cheon; Cheong, Seong Kyun [Seoul Nat' l Univ. of Science and Technology, Seoul (Korea, Republic of)

2012-11-15

The object of this study considers corrosion fatigue improvement of 7075-T6 aluminum by using shot peening treatment on 3.5% NaCl solution at room temperature. Aluminum alloy is generally used in aerospace structural components because of the light weight and high strength characteristics. Many studies have shown that an aluminum alloy can be approximately 50% lighter than other materials. Mostly, corrosion leads to earlier fatigue crack propagation under tensile conditions and severely reduces the life of structures. Therefore, the technique to improve material resistance to corrosion fatigue is required. Shot peening technology is widely used to improve fatigue life and other mechanical properties by induced compressive residual stress. Even the roughness of treated surface causes pitting corrosion, the compressive residual stress, which is induced under the surface layer of material by shot peening, suppersses the corrosion and increases the corrosion resistance. The experimental results for shot peened specimens were compared with previous work for non treated aluminum alloy. The results show that the shot peening treatment affects the corrosion fatigue improvement of aluminum alloys and the induced compressive residual stress by shot peening treatment improves the resistance to corrosion fatigue.

Effect of laser shock peening on residual stress and fatigue life of clad 2024 aluminium sheet containing scribe defects

International Nuclear Information System (INIS)

Dorman, M.; Toparli, M.B.; Smyth, N.; Cini, A.; Fitzpatrick, M.E.; Irving, P.E.

2012-01-01

Highlights: ► Effect of laser peen intensity on local residual stress fields in 2024 aluminium. ► Peening induces significant changes in surface topography and local hardness. ► Residual stress at peen spot centre in tension, spot overlap in compression. ► Notched fatigue lives increased; crack morphology correlated to residual stress field. ► Large peening power densities can cause fatigue life reduction in notched samples. - Abstract: Laser peening at a range of power densities has been applied to 2 mm-thick sheets of 2024 T351 aluminium. The induced residual stress field was measured using incremental hole drilling and synchrotron X-ray diffraction techniques. Fatigue samples were subjected to identical laser peening treatments followed by scribing at the peen location to introduce stress concentrations, after which they were fatigue tested. The residual stresses were found to be non-biaxial: orthogonal to the peen line they were tensile at the surface, moving into the desired compression with increased depth. Regions of peen spot overlap were associated with large compression strains; the centre of the peen spot remaining tensile. Fatigue lives showed moderate improvement over the life of unpeened samples for 50 μm deep scribes, and slight improvement for samples with 150 μm scribes. Use of the residual stress intensity K resid approach to calculate fatigue life improvement arising from peening was unsuccessful at predicting the relative effects of the different peening treatments. Possible reasons for this are explored.

Residual stress evaluation and curvature behavior of aluminium 7050 peen forming processed

International Nuclear Information System (INIS)

Oliveira, R.R. de; Lima, N.B.; Braga, A.P.V.; Goncalves, M.

2010-01-01

Shot peening is a superficial cold work process used to increase the fatigue life evaluated by residual stress measurements. The peen forming process is a variant of the shot peening process, where a curvature in the plate is obtained by the compression of the grains near to the surface. In this paper, the influence of the parameters such as: pressure of shot, ball shot size and thickness of aluminum 7050 samples with respect to residual stress profile and resulting arc height was studied. The evaluation of the residual stress profile was obtained by sin 2 Ψ method. (author)

Shot peening speed measurements using lidar technology

DEFF Research Database (Denmark)

Angelou, Nikolas; Zhang, Xiaodan; Sjöholm, Mikael

The shot peening technique is used for the surface modification of metallic components that are part of wind turbines, such as gears, bolts and blade coatings to prevent erosion. An important parameter of this technique is the dynamic energy of emitted shots. In this context the objective......, the risk of damaging the peening machine by installing an instrument inside the chamber during operation is eliminated by this approach. Laser anemometers are being researched and developed in the department of Wind Energy, mainly in the framework of the WindScanner.dk infrastructure project [1], but also...... validated and used in monitoring the wind conditions around wind turbines (wake and inflow), over complex terrain as well as offshore....

Role of residual stresses induced by double peening on fatigue durability of automotive leaf springs

International Nuclear Information System (INIS)

Scuracchio, Bruno Geoffroy; Batista de Lima, Nelson; Schön, Cláudio Geraldo

2013-01-01

Highlights: ► Proper choice of peening media is needed for higher fatigue strength in leaf springs. ► Optimum double-peening condition for leaf springs: 0.8 mm shot, followed by 0.3 mm. ► Fatigue life correlates with residual stress levels at the surface (up to 0.02 mm). ► Residual stress profile below 0.02 mm has no measurable effect over fatigue life. ► Failure of the investigated parts is nucleation-controlled. - Abstract: Improvement of fatigue life in parts subjected to cyclic stresses by application of mechanical surface treatment processes is already well known, both in the industry and in the academy. Dealing with automotive springs, the shot peening process becomes an essential step in manufacturing. In the case of leaf springs, however, a systematic investigation of the effect of shot peening on fatigue life is still required. The aim of the present work is to improve the knowledge on the role of shot peening in manufacturing leaf springs for vehicles, through the analysis of residual stresses by X-ray diffraction and fatigue tests on a series of samples that were subject to ten different peening schedules. Among the investigated processes, the usage of 0.8 mm diameter cast steel shot followed by a second peening with 0.3 mm diameter cast steel shot leads to optimal performance, regarding fatigue life. X-ray diffraction analysis shows that this improved performance may be attributed to residual compressive stress maintained until a depth of 0.02 mm below the surface, which directly influences fatigue crack nucleation. Residual stresses induced by shot peening in larger depths have no influence on the sample’s fatigue life

Experimental and Numerical Analysis of Microstructures and Stress States of Shot-Peened GH4169 Superalloys

Science.gov (United States)

Hu, Dianyin; Gao, Ye; Meng, Fanchao; Song, Jun; Wang, Rongqiao

2018-04-01

Combining experiments and finite element analysis (FEA), a systematic study was performed to analyze the microstructural evolution and stress states of shot-peened GH4169 superalloy over a variety of peening intensities and coverages. A dislocation density evolution model was integrated into the representative volume FEA model to quantitatively predict microstructural evolution in the surface layers and compared with experimental results. It was found that surface roughness and through-depth residual stress profile are more sensitive to shot-peening intensity compared to coverage due to the high kinetic energy involved. Moreover, a surface nanocrystallization layer was discovered in the top surface region of GH4169 for all shot-peening conditions. However, the grain refinement was more intensified under high shot-peening coverage, under which enough time was permitted for grain refinement. The grain size gradient predicted by the numerical framework showed good agreement with experimental observations.

Effects of shot peening on the residual stress of welded SS400 steel

International Nuclear Information System (INIS)

Lee, Jong Man; Kim, Tae Hyung; Cheong, Seong Kyun; Lee, Seung Ho

2002-01-01

The fatigue life of structures is usually determined by welding zone. The tensile residual stress, which is induced by welding, reduces the fatigue life and fatigue strength of welded structures. If we remove the tensile residual stress or induce the compressive residual stress, the fatigue life of welded structures will be improved. The change of hardness and compressive residual stress of welded zone after shot peening was investigated in this paper. The results show that the hardness was increased by shot peening. The residual stress was reduced by shot peening

Welding residual stress improvement in internal components by water jet peening

International Nuclear Information System (INIS)

Enomoto, K.; Hirano, K.; Hayashi, M.; Hayashi, E.

1996-01-01

Cavitations are generated when highly pressurized water is jetted in water. Surface residual stress is improved remarkably due to the peening effect of extremely high pressure caused by the collapse of cavitation bubbles. This technique is called water jet peening (WJP). WJP is expected to be an effective maintenance technique for the prevention of stress corrosion cracking caused by residual stress in various components of power generating plants. Various kinds of specimens were water jet peened to evaluate the fundamental characteristics of WJP and to select the most appropriate conditions for the residual stress improvement. Test results showed that WJP markedly improved the tensile residual stress caused by welding and grinding to the high compressive residual stress and seems to prevent the stress corrosion cracking

Effect of high energy shot peening pressure on the stress corrosion cracking of the weld joint of 304 austenitic stainless steel

International Nuclear Information System (INIS)

Zhiming, Lu; Laimin, Shi; Shenjin, Zhu; Zhidong, Tang; Yazhou, Jiang

2015-01-01

The weld joint of 304 stainless steel is treated using high energy shot peening(HESP) with various shot peening pressures. The grain size and metallographic microstructure of the specimen surface layer are analyzed using the X-ray diffraction method, and the surface hardness is measured. Slow strain rate tension tests are then performed to investigate the effect of shot peening pressure on the stress corrosion sensitivity. The results show that in the surface layer of the specimen, the grain refinement, hardness and the strain-induced plastic deformation all increase with the increasing shot peening pressure. Martensitic transformation is observed in the surface layer after being treated with HESP. The martensite phase ratio is found to increase with increasing shot peening pressure. The result also shows that the effects of the shot peening treatment on the stress corrosion sensitivity index depend on the shot peening pressure. When the shot peening pressure is less than 0.4 MPa, the grain refinement effect plays the main role, and the stress corrosion sensitivity index decreases with the increasing shot peening pressure. In contrast, when the shot peening pressure is higher than 0.4 MPa, the martensite transformation effect plays the main role, the stress corrosion sensitivity index increases with increasing shot peening pressure

Effect of Shot Peening on Tribological Behaviors of Molybdenum-Thermal Spray Coating using HVOF Method

Directory of Open Access Journals (Sweden)

H. Mohassel

2017-03-01

Full Text Available We have investigated the influence of post-shot peening on Mo-coating as compared to substrate steel 16MnCr5 (according to ZFN-413 A. Shot peening of carburized steel discs with and without Mo-coating was performed by using Shot size S230, Almen intensity 0.42 mm ’A’ and exposure time 96 sec. Tribological properties were analyzed, using pin-on-disc tribometer apparatus, under dry sliding conditions at different specific applied loads, sliding velocities and distance. Typical standardized methods were used for studying of surface integrity parameters (micro-hardness, topography and surface roughness. Surface morphology of the Mo-coating specimens with and without Shot Peening before and after wear was evaluated by Scanning Electron Microscopy. The results showed that shot peening after Mo-coating has considerable effect on improving wear resistance and because of having low friction coefficient has showed better wear behavior and tribologi cal properties over that of the un-peened Mo-coating.

Intermediarios radiales del movimiento roto-traslatorio de satélites artificiales

OpenAIRE

Soler Vera, Francisco Alejandro

2016-01-01

En esta tesis se presentan algunos modelos intermediarios del movimiento roto-traslatorio de un satélite u otro cuerpo celeste menor alrededor de uno esférico y mucho más masivo, considerando condiciones iniciales para las cuales la perturbación gravitatoria es la predominante sobre otros tipos de perturbaciones como la magnética o la aerodinámica, entre otras. En particular, analizaremos el conocido como “problema de gradiente de gravedad”, esto es, la aproximación de MacCullagh del desarr...

Effect of laser shot peening on precipitation hardened aluminum alloy 6061-T6 using low energy laser

Science.gov (United States)

Sathyajith, S.; Kalainathan, S.

2012-03-01

Mechanical properties of engineering material can be improved by introducing compressive residual stress on the material surface and refinement of their microstructure. Variety of mechanical process such as shot peening, water jet peening, ultrasonic peening, laser shot peening were developed in the last decades on this contrast. Among these, lasers shot peening emerged as a novel industrial treatment to improve the crack resistance of turbine blades and the stress corrosion cracking (SCC) of austenic stainless steel in power plants. In this study we successfully performed laser shot peening on precipitation hardened aluminum alloy 6061-T6 with low energy (300 mJ, 1064 nm) Nd:YAG laser using different pulse densities of 22 pulses/mm 2 and 32 pulses/mm 2. Residual stress evaluation based on X-ray diffraction sin 2 ψ method indicates a maximum of 190% percentage increase on surface compressive stress. Depth profile of micro-hardness shows the impact of laser generated shock wave up to 1.2 mm from the surface. Apart from that, the crystalline size and micro-strain on the laser shot peened surfaces have been investigated and compared with the unpeened surface using X-ray diffraction in conjunction with line broadening analysis through the Williamson-Hall plot.

A Study on the Microstructural Evolution of a Low Alloy Steel by Different Shot Peening Treatments

Directory of Open Access Journals (Sweden)

Juan González

2018-03-01

Full Text Available Recent studies have shown that severe shot peening can be categorized as a severe plastic deformation surface treatment that is able to strongly modify the microstructure of the surface layer of materials, by both increasing the dislocation density and introducing a large number of defects that define new grain boundaries and form ultrafine structure. In this work, conventional shot peening and severe shot peening treatments were applied to 39NiCrMo3 steel samples. The samples were characterized in terms of microstructure, surface roughness, microhardness, residual stresses, and surface work-hardening as a function of surface coverage. Particular attention was focused on the analysis of the microstructure to assess the evolution of grain size from the surface to the inner material to capture the gradient microstructure. Severe shot peening proved to cause a more remarkable improvement of the general mechanical characteristics compared to conventional shot peening; more significant improvement was associated with the microstructural alteration induced by the treatment. Our datas provide a detailed verification of the relationship between shot peening treatment parameters and the microstructure evolution from the treated surface to the core material.

Effect of shot peening process on fatigue behavior of an alloyed austempered ductile iron

Directory of Open Access Journals (Sweden)

Amir Sadighzadeh Benam

2011-08-01

Full Text Available Shot peening is one of the most common surface treatments to improve the fatigue behavior of metallic parts. In this study the effect of shot peening process on the fatigue behavior of an alloyed austempered ductile iron (ADI has been studied. Austempering heat treatment consisted of austenitizing at 875℃ for 90 min followed by austempering at three different temperatures of 320, 365 and 400℃. Rotating-bending fatigue test was carried out on samples after shot peening by 0.4 – 0.6 mm shots. XRD and SEM analysis, micro hardness and roughness tests were carried out to study the fatigue behavior of the samples. Results indicate that the fatigue strengths of samples austempered at 320, 365 and 400℃ are increased by 27.3%, 33.3% and 48.4%, respectively, after shot peening process.

Shot peening of doel 3 plant

International Nuclear Information System (INIS)

Slama, G.; Sort, M.

1985-12-01

The process implementation for DOEL consisted in: developing tooling and test procedures for an industrial application including ALARA considerations; qualifying process, tooling and procedures using representative conditions (full size mock-up, of steam generator channel head and associated working area); Establishing the reliability of tooling and procedures to comply permanently with the required criteria (chiefly Almen Intensity); and training and qualifying personnel. A variety of tests were performed by FRAMATOME and BELGATOM to qualify the process and characterize its effects on both inside and outside diameters of the tubes. These are: Mg Cl 2 ; 10% caustic tests at high temperature and pressure; tetrathionate; strain gauges and X rays stresses measurements; effects on precracked tubes; Leak tests after shot peening. The operation was performed at Doel in July 1985. Laboratory tests performed on mockups by FRAMATOME and BELGATOM could demonstrate that on tubes without cracks no difference was found between Eddy current signals from tubes shot-peened or not

Numerical investigation of a shot peening process by a finite element approach

DEFF Research Database (Denmark)

Liu, Hongsheng; Zhang, Xiaodan; Hansen, Niels

2014-01-01

Shot peening is a surface impact treatment widely used to improve the performance of a metal or a component. The better performance of the shot peened part is controlled by compressive residual stresses resulting from the plastic deformation of the surface layers by impacts of shot. The compressive...... residual stress is generally measured by X-ray diffraction. However, considerable cost and time are needed for such measurements. For this reason, in this work a 3D finite element (FE) model is introduced for a shot peening process. Through the FE simulations, the effect of process parameters...... such as damping ratio of material, friction coefficient, shot velocity and shot angle on the magnitude and distribution of the compressive residual stress is examined....

Influence of laser shock peening on irradiation defects in austenitic stainless steels

Energy Technology Data Exchange (ETDEWEB)

Lu, Qiaofeng [Department of Mechanical & Materials Engineering, University of Nebraska–Lincoln, Lincoln, NE 68588 (United States); Su, Qing [Nebraska Center for Energy Sciences Research, University of Nebraska–Lincoln, Lincoln, NE 68588 (United States); Wang, Fei [Department of Mechanical & Materials Engineering, University of Nebraska–Lincoln, Lincoln, NE 68588 (United States); Zhang, Chenfei; Lu, Yongfeng [Department of Electrical Engineering, University of Nebraska–Lincoln, Lincoln, NE 68588 (United States); Nastasi, Michael [Department of Mechanical & Materials Engineering, University of Nebraska–Lincoln, Lincoln, NE 68588 (United States); Nebraska Center for Energy Sciences Research, University of Nebraska–Lincoln, Lincoln, NE 68588 (United States); Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, NE 68588 (United States); Cui, Bai, E-mail: bcui3@unl.edu [Department of Mechanical & Materials Engineering, University of Nebraska–Lincoln, Lincoln, NE 68588 (United States); Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, NE 68588 (United States)

2017-06-15

The laser shock peening process can generate a dislocation network, stacking faults, and deformation twins in the near surface of austenitic stainless steels by the interaction of laser-driven shock waves with metals. In-situ transmission electron microscopy (TEM) irradiation studies suggest that these dislocations and incoherent twin boundaries can serve as effective sinks for the annihilation of irradiation defects. As a result, the irradiation resistance is improved as the density of irradiation defects in laser-peened stainless steels is much lower than that in untreated steels. After heating to 300 °C, a portion of the dislocations and stacking faults are annealed out while the deformation twins remain stable, which still provides improved irradiation resistance. These findings have important implications on the role of laser shock peening on the lifetime extension of austenitic stainless steel components in nuclear reactor environments. - Highlights: •Laser shock peening generates a dislocation network, stacking faults and deformation twins in stainless steels. •Dislocations and incoherent twin boundaries serve as effective sinks for the annihilation of irradiation defects. •Incoherent twin boundaries remain as stable and effective defect sinks at 300 °C.

Finite element analysis for prediction of the residual stresses induced by shot peening II

International Nuclear Information System (INIS)

Kim, Cheol; Seok, Chang Sung; Yang, Won Ho; Ryu, Myung Hai

2002-01-01

Shot peening is a surface impact treatment widely used to improve the performance of metal parts and welded details subjected to fatigue loading, contact fatigue, stress corrosion and other damage mechanisms. The better performance of the peened parts is mainly due to the residual stresses resulting from the plastic deformation of the surface layers of the material caused by the impact of the shot. In this paper the simulation technique is applied to predict the magnitude and distribution of the residual stress and plastic deformation caused by shot peening with the help of finite element analysis

Peen treatment on a titanium implant: effect of roughness, osteoblast cell functions, and bonding with bone cement

Directory of Open Access Journals (Sweden)

Khandaker M

2016-02-01

Full Text Available Morshed Khandaker,1,4 Shahram Riahinezhad,1 Fariha Sultana,1 Melville B Vaughan,2,4 Joshua Knight,2 Tracy L Morris3,4 1Department of Engineering & Physics, 2Department of Biology, 3Department of Mathematics and Statistics, 4Center for Interdisciplinary Biomedical Education and Research, University of Central Oklahoma, Edmond, OK, USA Abstract: Implant failure due to poor integration of the implant with the surrounding biomaterial is a common problem in various orthopedic and orthodontic surgeries. Implant fixation mostly depends upon the implant surface topography. Micron to nanosize circular-shaped groove architecture with adequate surface roughness can enhance the mechanical interlock and osseointegration of an implant with the host tissue and solve its poor fixation problem. Such groove architecture can be created on a titanium (Ti alloy implant by laser peening treatment. Laser peening produces deep, residual compressive stresses in the surfaces of metal parts, delivering increased fatigue life and damage tolerance. The scientific novelty of this study is the controlled deposition of circular-shaped rough spot groove using laser peening technique and understanding the effect of the treatment techniques for improving the implant surface properties. The hypothesis of this study was that implant surface grooves created by controlled laser peen treatment can improve the mechanical and biological responses of the implant with the adjoining biomaterial. The objective of this study was to measure how the controlled laser-peened groove architecture on Ti influences its osteoblast cell functions and bonding strength with bone cement. This study determined the surface roughness and morphology of the peen-treated Ti. In addition, this study compared the osteoblast cell functions (adhesion, proliferation, and differentiation between control and peen-treated Ti samples. Finally, this study measured the fracture strength between each kind of Ti samples

Residual stress behaviors induced by laser peening along the edge of curved models

International Nuclear Information System (INIS)

Im, Jong Bin; Grandhi, Ramana V.; Ro, Young Hee

2012-01-01

Laser peening (LP) induces high magnitude compressive residual stresses in a small region of a component. The compressive residual stresses cause plastic deformation that is resistant to fatigue fracture. Fatigue cracks are generally nucleated at critical areas, and LP is applied for those regions so as to delay the crack initiation. Many critical regions are located on the edge of the curved portion of structures because of stress concentration effects. Several investigations that are available for straight components may not give meaningful guidelines for peening curved components. Therefore, in this paper, we investigate residual stress behaviors induced by LP along the edge of curved models. Three curved models that have different curvatures are investigated for peening performance. Two types of peening configurations, which are simultaneous corner shot and sequential corner shots, are considered in order to obtain compressive residual stresses along an edge. LP simulations of multiple shots are performed to identify overlapping effects on the edge portion of a curved model. In addition, the uncertainty calculation of residual stress induced by LP considering laser pulse duration is performed

Assessment of surface hardening effects from shot peening on a Ni-based alloy using electron backscatter diffraction techniques

International Nuclear Information System (INIS)

Child, D.J.; West, G.D.; Thomson, R.C.

2011-01-01

An electron backscatter diffraction (EBSD)-based tool is described to assess the depth of strain-hardening effects of shot-peening treatments applied to the Ni-based superalloy, Udimet (copy right) alloy 720Li. The method consists of a statistical analysis of a number of data points from each grain scanned based on the grain orientation spread and their relative position from the shot-peened edge. The output is a quantitative measure of the depth of strain-hardening effects. The tool is used at various shot-peening intensities to demonstrate the ability to distinguish between these changes, using a range of intensities from 4 to 10 Almen. An increase in shot-peening intensity is observed to increase the depth of strain-hardening effects in the alloy. A comparison with residual stress measurements using X-ray diffraction for the same material shows that the strain-hardened depth determined by EBSD extends to approximately half the distance of the residual stress present due to shot peening. A comparison is also made with predicted profiles from the Peenstress SM model and subsequent microhardness testing. A positive correlation is observed between strained hardened depth and surface roughness of the peened samples. In each case, the increases in surface roughness and strain-hardened depth diminish toward the upper end of the shot-peening intensity range studied for this alloy.

The influence of shot peening on the fatigue and corrosion properties of an austenitic stainless steel for surgical implants

International Nuclear Information System (INIS)

Wieser, H.

1997-01-01

To roughen the surface surgical implants are often peened with granular media. Local depressions formed by the peening process lower the fatigue and corrosion resistance. This negative effect can be avoided by shot peening with spherical particles, which leads to high compressive residual stresses near the surface. As it is shown in this work several kinds of surface flaws like overlappings, cracks and sharp edged notches are formed by shot peening. Their form and depth and the reasons for their occurrence are not well known since the commonly used measurements with a stylus tip cannot detect them. For this reason sharp edged metallographic sections which represent the surface profile are examined. In order to estimate the maximum depth of these depressions a statistical model was developed applying the theory of statistics of extreme values. The influence of shot peening on fatigue and corrosion behavior is examined by fatigue tests in air, physiological NaCl-solution and by electrochemical corrosion tests. An increase of the fatigue resistance in air can be obtained by shot peening with large ceramic particles (0,6 mm to 0,8 mm) and low peening pressure since these conditions generate smaller surface flaws than with small balls and high pressure. In physiological NaCl-solution the fatigue resistance decreases after the shot peening treatment. This can be related to crevices formed by overlappings and cracks. Removal by subsequent electrolytical polishing the corrosion fatigue resistance increases again. (author)

Influence of laser shock peening on irradiation defects in austenitic stainless steels

Science.gov (United States)

Lu, Qiaofeng; Su, Qing; Wang, Fei; Zhang, Chenfei; Lu, Yongfeng; Nastasi, Michael; Cui, Bai

2017-06-01

The laser shock peening process can generate a dislocation network, stacking faults, and deformation twins in the near surface of austenitic stainless steels by the interaction of laser-driven shock waves with metals. In-situ transmission electron microscopy (TEM) irradiation studies suggest that these dislocations and incoherent twin boundaries can serve as effective sinks for the annihilation of irradiation defects. As a result, the irradiation resistance is improved as the density of irradiation defects in laser-peened stainless steels is much lower than that in untreated steels. After heating to 300 °C, a portion of the dislocations and stacking faults are annealed out while the deformation twins remain stable, which still provides improved irradiation resistance. These findings have important implications on the role of laser shock peening on the lifetime extension of austenitic stainless steel components in nuclear reactor environments.

The effect of controlled shot peening on fusion welded joints

International Nuclear Information System (INIS)

Lah, Nur Azida Che; Ali, Aidy; Ismail, Napsiah; Chai, Lim Poon; Mohamed, Abdul Aziz

2010-01-01

This work examines the effect of controlled shot peening (CSP) treatment on the fatigue strength of an ASTM A516 grade 70 carbon steel welded joint. Metallurgical modifications, hardness, elemental compositions, and internal discontinuities, such as porosity, inclusions, lack of penetration, and undercut found in treated and untreated fusion welded joints, were characterized. The fatigue results of as-welded and peened skimmed joints were compared. It was observed that the effect of the CSP and skimming processes improved the fatigue life of the fusion weld by 50% on MMA-welded, 63% on MIG-welded, and 60% on TIG-welded samples.

Application of Ultra High Pressure Cavitation Peening to Prevent PWSCC on Primary Plant Components

Energy Technology Data Exchange (ETDEWEB)

Poling, G.R.

2015-07-01

Primary Water Stress Corrosion Cracking (PWSCC) on Alloy 600/82/182 susceptible materials can lead to increased costs for maintenance and repair/replacement activities on nuclear power plant primary components. A process called Ultra High Pressure (UHP) cavitation peening can be safely and cost effectively applied to the susceptible materials to generate compressive stresses on the surface and prevent PWSCC initiation. AREVA has developed the tooling systems to apply the UHP cavitation peening process on reactor vessel head penetration nozzles, bottom mounted nozzles and primary nozzles. Applying the UHP cavitation peening process before PWSCC initiation will prevent future repairs/replacements, reduce maintenance costs, and provide more effective on-time for the reactor. (Author)

3-D analysis of fatigue crack behaviour in a shot peened steam turbine blade material

Energy Technology Data Exchange (ETDEWEB)

He, B.Y., E-mail: Binyan.he@soton.ac.uk [Engineering Materials, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom); Katsamenis, O.L. [muVIS X-ray Imaging Centre, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom); Mellor, B.G.; Reed, P.A.S. [Engineering Materials, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom)

2015-08-26

Serial mechanical sectioning and high resolution X-ray tomography have been used to study the three-dimensional morphology of small fatigue cracks growing in a 12 Cr tempered martensitic steam turbine blade material. A range of surface conditions has been studied, namely polished and shot peened (with varying levels of intensity). In the polished (unpeened) condition, inclusions (alumina and manganese sulphide) played an important role in initiating and controlling early fatigue crack behaviour. When fatigue cracks initiated from an alumina stringer, the crack morphology was normally dominated by single stringers, which were always in the centre of the fatigue crack, indicating its primary role in initiation. Manganese sulphide inclusion groups however seemed to dominate and affect the crack path along both the surface and depth crack growth directions. The more intensely shot peened condition did not however evidence inclusion or stringer affected fatigue crack initiation or growth behaviour; sub-surface crack coalescence being clearly observed by both serial sectioning and computed tomography (CT) imaging techniques at a depth of about 150–180 μm. These sub-surface crack coalescences can be linked to both the extent of the compressive residual stress as well as the depth of the plastic deformation arising from the intense shot peening process. Shot peening appears to provide a different defect population that initiates fatigue cracks and competes with the underlying metallurgical defect populations. The most beneficial shot peening process would in this case appear to “deactivate” the original metallurgical defect population and substitute a known defect distribution from the shot peening process from which fatigue cracks grow rather slowly in the strain hardened surface layer which also contains compressive residual stresses. A benefit to fatigue life in bending, even under Low Cycle Fatigue (LCF) conditions, has been observed in these tests if a

Effects of Oxidation and fractal surface roughness on the wettability and critical heat flux of glass-peened zirconium alloy tubes

International Nuclear Information System (INIS)

Fong, R.W.L.; Nitheanandan, T.; Bullock, C.D.; Slater, L.F.; McRae, G.A.

2003-05-01

Glass-bead peening the outside surfaces of zirconium alloy tubes has been shown to increase the Critical Heat Flux (CHF) in pool boiling of water. The CHF is found to correlate with the fractal roughness of the metal tube surfaces. In this study on the effect of oxidation on glass-peened surfaces, test measurements for CHF, surface wettability and roughness have been evaluated using various glass-peened and oxidized zirconium alloy tubes. The results show that oxidation changes the solid-liquid contact angle (i.e., decreases wettability of the metal-oxide surface), but does not change the fractal surface roughness, appreciably. Thus, oxidation of the glass-peened surfaces of zirconium alloy tubes is not expected to degrade the CHF enhancement obtained by glass-bead peening. (author)

Study on mitigation of stress corrosion cracking by peening

International Nuclear Information System (INIS)

Maeguchi, Takaharu; Tsutsumi, Kazuya; Toyoda, Masahiko; Ohta, Takahiro; Okabe, Taketoshi; Sato, Tomonobu

2010-01-01

In order to verify stability of residual stress improvement effect of peeing for mitigation of stress corrosion cracking in components of PWR plant, relaxation behavior of residual stress induced by water jet peening (WJP) and ultrasonic shot peening (USP) on surface of alloy 600 and its weld metal was investigated under various thermal aging and stress condition considered for actual plant operation. In the case of thermal aging at 320-380degC, surface residual stress relaxation was observed at the early stage of thermal aging, but no significant stress relaxation was observed after that. Applied stress below yield stress does not significantly affect stress relaxation behavior of surface residual stress. Furthermore, it was confirmed that cyclic stress does not accelerate stress relaxation. (author)

Finite element modelling of coverage effects during shot peening of IN718

Energy Technology Data Exchange (ETDEWEB)

Zimmermann, Marc; Hoffmeister, Juergen [Inst. fuer Werkstoffkunde I, Karlsruhe Inst. of Tech. (Germany); Schulze, Volker [Inst. fur Produktionstechnik, Karlsruhe Inst. of Tech. (Germany)

2010-08-15

Current 3D shot peening simulation models proposed in literature do not take into account coverage as a process parameter influencing the residual state after shot peening. In this study a classic approach, using an ordered dimple pattern, and a new approach, using a stochastic dimple pattern were tested to describe the correlation between coverage, the surface topography and the residual stress state. Model verification was conducted based on X-ray and confocal white light microscopy measurements on shot peened test specimens. The test material was age hardened IN718. Simulations showed that the dimple pattern and the impact order of the shots can have a strong influence on the calculated macroscopic residual stress state. The stochastic approach enabled a realistic prediction of the surface topography and the residual stress state for arbitrary values of coverage while the classic approach strongly underestimated the number of shot impacts needed to achieve a certain value of coverage. (orig.)

Development of portable laser peening systems for nuclear power reactors

International Nuclear Information System (INIS)

Chida, Itaru; Uehara, Takuya; Yoda, Masaki; Miyasaka, Hiroyuki; Kato, Hiromi

2009-01-01

Stress corrosion cracking (SCC) is the major factor to reduce the reliability of aged reactor components. Toshiba has developed various laser-based maintenance and repair technologies and applied them to existing nuclear power plants. Laser-based technology is considered to be the best tool for remote processing in nuclear power plants, and particularly so for the maintenance and repair of reactor core components. Accessibility could be drastically improved by a simple handling system owing to the absence of reactive force against laser irradiation and the flexible optical fiber. For the preventive maintenance, laser peening technology was developed and applied to reactor components in operating BWRs and PWRs. Laser peening is a novel process to improve residual stress from tensile to compressive on material surface layer by irradiating focused high-power laser pulses in water without any surface preparations. Laser peening systems, which deliver laser pulses with mirrors or through an optical fiber, were developed and have been applied to preventive maintenance against SCC in nuclear power reactors since 1999. Each system was composed of laser oscillators, a beam delivery system, a laser irradiation head, remote handling equipment and a monitor/control system. Beam delivery with mirrors was accomplished through alignment/tracking functions with sufficient accuracy. Reliable fiber-delivery was attained by the development of a novel input coupling optics and an irradiation head with auto-focusing. Recently, we have developed portable laser peening (PLP) system which could employ both mirror- and fiber- delivery technologies. Size and weight of the PLP system for BWR bottom was almost 1/25 compared to the previous system. PLP system would be the applicable to both BWRs and PWRs as one of the maintenance technologies. (author)

Shot Peening Effects on Subsurface Layer Properties and Fatigue Performance of Case-Hardened 18CrNiMo7-6 Steel

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H. S. Ho

2018-01-01

Full Text Available The present study is conducted with a dual-aim: firstly, to examine the effect of several single shot peening conditions on the subsurface layer properties and fatigue performance of the case-hardened 18CrNiMo7-6 steel, and secondly, to propose an optimized peening condition for improved fatigue performance. By carrying out the subsurface integrity analysis and fatigue testing, the underlying relationships among the peening process, subsurface layer property and fatigue performance are investigated, the way peening conditions affect the fatigue life and its associated scatter for the case-hardened 18CrNiMo7-6 steel is quantitatively assessed. The in-depth study shows that dual peening can be an optimized solution, for it is able to produce a subsurface layer with enhanced properties and eventually gain a significant improvement in fatigue performance.

Wavelength dependent deformation in a laser peened Ti-2.5Cu alloy

Energy Technology Data Exchange (ETDEWEB)

Umapathi, A., E-mail: umapathi.arimakula@gmail.com; Swaroop, S., E-mail: n.r.sathya.swaroop@gmail.com

2017-01-27

Laser peening without coating (LPwC) was performed on a Ti-2.5Cu alloy at wavelengths of 1064 and 532 nm and at a constant power density of approximately 7 GW cm{sup −2} with overlap rates of 53%, 63% and 73%. Surface softening due to thermal interaction of laser beam with material was observed till a depth of 500 µm (at 532 nm) and 200 µm (at 1064 nm), based on hardness data. This was corroborated (rather weakly) by residual stress analysis. In addition, softening due to mechanical effects (adiabatic heating) was observed in the bulk. Although there was an increase in mechanical softening with increase in overlap rates at 532 nm, it was observed, upon comparison with peened samples at 1064 nm, that the mechanical softening is a function of wavelength of radiation used for peening. It was observed that the onset of softening was earlier if the wavelength was shorter. Further, evidence of hardening in the form of twinning was found for the 1064 nm case while it was absent for the 532 nm case, for 73% overlap. The workhardened depth was more than 1000 µm, not observed in earlier studies based on residual stress analysis. The direct consequence of softening effect was found in the fatigue results. The fatigue life extended by a factor of 1.4 and 2.3 for the samples peened at 532 nm and 1064 nm respectively, consistent with the observed wavelength dependent onset of softening.

Laser shock peening on a 6056-T4 aluminium alloy for airframe applications

CSIR Research Space (South Africa)

Glaser, D

2014-03-01

Full Text Available stream_source_info Pityana1_2014_ABSTRACT ONLY.pdf.txt stream_content_type text/plain stream_size 1356 Content-Encoding ISO-8859-1 stream_name Pityana1_2014_ABSTRACT ONLY.pdf.txt Content-Type text/plain; charset=ISO-8859-1... Laser Shock Peening on a 6056-T4 Aluminium Alloy for Airframe Applications Daniel Glaser, Claudia Polese, Rachana D. Bedekar, Jasper Plaisier,Sisa Pityana, Bathusile Masina, Tebogo Mathebula, and Enrico Troiani Keywords: Laser Shock Peening...

Device and process for controlling the shoot peening efficiency, of a steam generator tube inner surface

International Nuclear Information System (INIS)

Isnardon, G.; Jacquier, P.; Voisembert, S.

1988-01-01

This device comprises an outer envelope of tubular shape applied on the face of the tubular plate around one end of the tube to be peened. A tool comprising a nozzle for the projection of the peening particles is axially mounted in the outer envelope. The controlling device comprises at least one piezoelectric sensor arranged to be in contact with the wall of the outer envelope and measuring means for the electrical signal generated by the sensor. The projection nozzle is brought into the outer envelope at the level of the sensor after each peening operation and the electrical voltage of the signal produced by the sensor is measured [fr

Effect of shot peening using ultra-fine particles on fatigue properties of 5056 aluminum alloy under rotating bending

Energy Technology Data Exchange (ETDEWEB)

Kikuchi, Shoichi, E-mail: kikuchi@mech.kobe-u.ac.jp [Department of Mechanical Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe-shi, Hyogo 657-8501 (Japan); Nakamura, Yuki [Department of Mechanical Engineering, National Institute of Technology, Toyota College, 2-1 Eisei-cho, Toyota-shi, Aichi 471-8525 (Japan); Nambu, Koichiro [Department of Mechanical Engineering, National Institute of Technology, Suzuka College, Shiroko-cho, Suzuka-shi, Mie 510-0294 (Japan); Ando, Masafumi [Innovation Team, IKK SHOT Co. Ltd., 412-4, Nunowari, Minami-Shibata-machi, Tokai-shi, Aichi 476-0001 (Japan)

2016-01-15

Shot peening using particles 10 μm in diameter (ultra-fine particle peening: Ultra-FPP) was introduced to improve the fatigue properties of 5056 aluminum alloy. The surface microstructures of the Ultra-FPP treated specimens were characterized using a micro-Vickers hardness tester, scanning electron microscopy (SEM), X-ray diffraction (XRD), non-contact scanning white light interferometry, and electron backscatter diffraction (EBSD). The Ultra-FPP treated specimen had higher hardness than the conventional FPP treated specimen with a short nozzle distance due to the high velocity of the ultra-fine particles. Furthermore, the surface hardness of the Ultra-FPP treated specimen tended to increase as the peening time decreased. Fatigue tests were performed in air at room temperature using a cantilever-type rotating bending fatigue testing machine. It was found that the fatigue life of the Ultra-FPP treated specimen tended to increase with decreasing peening time. Mainly, the Ultra-FPP improved the fatigue properties of 5056 aluminum alloy in the very high cycle regime of more than 10{sup 7} cycles compared with the un-peened specimens. This is because the release of the compressive residual stress is small during fatigue tests at low stress amplitudes.

Effects of Shot-Peening and Stress Ratio on the Fatigue Crack Propagation of AL 7475-T7351 Specimens

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Natália Ferreira

2018-03-01

Full Text Available Shot peening is an attractive technique for fatigue enhanced performance of metallic components, because it increases fatigue crack initiation life prevention and retards early crack growth. Engineering design based on fatigue crack propagation predictions applying the principles of fracture mechanics is commonly used in aluminum structures for aerospace engineering. The main purpose of present work was to analyze the effect of shot peening on the fatigue crack propagation of the 7475 aluminum alloy, under both constant amplitude loading and periodical overload blocks. The tests were performed on 4 and 8 mm thickness specimens with stress ratios of 0.05 and 0.4. The analysis of the shot-peened surface showed a small increase of the micro-hardness values due to the plastic deformations imposed by shot peening. The surface peening beneficial effect on fatigue crack growth is very limited; its main effect is more noticeable near the threshold. The specimen’s thickness only has marginal influence on the crack propagation, in opposite to the stress ratio. Periodic overload blocks of 300 cycles promotes a reduction of the fatigue crack growth rate for both intervals of 7500 and 15,000 cycles.

The finite element analysis for prediction of residual stresses induced by shot peening

International Nuclear Information System (INIS)

Kim, Cheol; Yang, Won Ho; Sung, Ki Deug; Cho, Myoung Rae; Ko, Myung Hoon

2000-01-01

The shot peening is largely used for a surface treatment in which small spherical parts called shots are blasted on a surface of a metallic components with velocities up to 100m/s. This treatment leads to an improvement of fatigue behavior due to the developed compressive residual stresses, and so it has gained widespread acceptance in the automobile and aerospace industries. The residual stress profile on surface layer depends on the parameters of shot peening, which are, shot velocity, shot diameter, coverage, impact angle, material properties etc. and the method to confirm this profile is only measurement by X-ray diffractometer. Despite its importance to automobile and aerospace industries, little attention has been devoted to the accurate modeling of the process. In this paper, the simulation technique is applied to predict the magnitude and distribution of the residual stress and plastic deformation caused by shot peening with the help of the finite element analysis

A Note on the Inverse Reconstruction of Residual Fields in Surface Peened Plates

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S. Ali Faghidian

Full Text Available Abstract A modified stress function approach is developed here to reconstruct induced stress, residual stress and eigenstrain fields from limited experimental measurements. The present approach is successfully applied to three experimental measurements set in surface peened plates with shallow shot peening affected zone. The well-rehearsed advantage of the proposed approach is that it not only minimizes the deviation of measurements from its approximations but also will result in an inverse solution satisfying a full range of continuum mechanics requirements. Also, the effect of component thickness as a geometric parameter influencing the residual stress state is comprehensively studied. A key finding of present study is that the plate thickness has no influence on the maximum magnitude of eigenstrain profile and compressive residual stresses within the shot peening affected zone while having a great influence on the magnitude of tensile residual stress and the gradient of linear residual stresses present in deeper regions.

Osseointegration improvement by shot peening in titanium dental implants

International Nuclear Information System (INIS)

Aparicio, C.; Gil, F.J.; Planell, J.A.; Padros, A.; Peraire, C.

1998-01-01

In order to optimize the implant-bone fixation, different shot peening treatments with different shot particles (TiO 2 , Al 2 O 3 ; SiC) have been made. The influence that each type of shot particle has in the bone colonization on the different treatment surfaces has been determined by means of osteoblast-like cells culture. Commercially pure titanium discs have been shot peened. Their qualitative and quantitative surface roughness have been characterized; as well as their surface contamination caused by the shot particles. Particle size has also been determined, before and after the treatment, in order to evaluate their breaking averages. Finally, a TiO 2 shot particles manufacture process by sintering has been developed. The manufacture has been necessary since this type of shot particles are not available in the market with the adequate size. (Author) 10 refs

On the residual stress modeling of shot-peened AISI 4340 steel: finite element and response surface methods

Science.gov (United States)

Asgari, Ali; Dehestani, Pouya; Poruraminaie, Iman

2018-02-01

Shot peening is a well-known process in applying the residual stress on the surface of industrial parts. The induced residual stress improves fatigue life. In this study, the effects of shot peening parameters such as shot diameter, shot speed, friction coefficient, and the number of impacts on the applied residual stress will be evaluated. To assess these parameters effect, firstly the shot peening process has been simulated by finite element method. Then, effects of the process parameters on the residual stress have been evaluated by response surface method as a statistical approach. Finally, a strong model is presented to predict the maximum residual stress induced by shot peening process in AISI 4340 steel. Also, the optimum parameters for the maximum residual stress are achieved. The results indicate that effect of shot diameter on the induced residual stress is increased by increasing the shot speed. Also, enhancing the friction coefficient magnitude always cannot lead to increase in the residual stress.

AN EFFECT OF SHOT PEENING ON GROWTH AND RETARDATION OF PHYSICALLY SHORT FATIGUE CRACKS IN AN AIRCRAFT Al-ALLOY

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Ivo Černý

2009-11-01

Full Text Available Results of an investigation of effect of shot peening on development of physically short fatigue crack in an aircraft V-95 Al-alloy, which is of a similar type as 7075 alloy, are described and discussed in the paper. The first part deals with adaptation and verification of direct current potential drop method for detection and measurement of short crack initiation and growth. The specific material and quite large dimensions of flat specimens with side necking of a low stress concentration factor had to be considered when position of electrodes was specified and the measurement method verified. The specimen type and dimensions were proposed taking account of the investigation of shot peening effects. Physically short fatigue cracks of the length from 0.2 mm to more than 3 mm, most of them between 0.8 – 1.5 mm, were prepared under high cycle fatigue loading of a constant nominal stress amplitude plus/minus 160 MPa. Specimens with existing short fatigue cracks were shot peened using two different groups of parameters. Development of crack growth after shot peening was measured and compared with crack growth in specimens without shot peening. Retardation of crack growth was significant particularly with cracks shorter than 2 mm. For the specific stress amplitude, evaluated results enable to estimate threshold length of defects, which after the application of shot peening will be reliably arrested.

Shot-peening effect on the structure, microhardness, and compressive stresses of the austenitic steel 1.4539

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Barbara Nasiłowska

2015-06-01

Full Text Available This article presents shot-peening effect on the structure, microhardness, and compressive stresses of the austenitic steel 1.4539. The research shows strengthening of the top layer and the formation of compressive stresses in the subsurface layers of the shot-peening elements.[b]Keyword[/b]: austenitic steel 1.4539, residual stresses, Waisman-Phillips’a method

Integration of Heat Treatment with Shot Peening of 17-4 Stainless Steel Fabricated by Direct Metal Laser Sintering

Science.gov (United States)

AlMangour, Bandar; Yang, Jenn-Ming

2017-11-01

Direct metal laser sintering (DMLS) is a promising powder-based additive manufacturing process for fabrication of near-net-shape parts. However, the typically poor fatigue performance of DMLS parts must be addressed for use in demanding industrial applications. Post-treatment can be applied to enhance the performance of such components. Earlier attempts at inducing grain refinement through severe plastic deformation of part surfaces using shot peening improved the physical and mechanical properties of metals without chemical alteration. However, heat treatment can modify the surface-hardening effects attained by shot peening. Hence, we examined the feasibility of applying shot peening combined with heat treatment to improve the performance of DMLS-fabricated 17-4 stainless steel parts through microstructural evolution studies and hardness measurements. Compared to a specimen treated only by shot peening, the sample exposed to additional heat treatment showed increased hardness due to aging of the dominant phase.

Estimation of fatigue strength enhancement for carburized and shot-peened gears

Science.gov (United States)

Inoue, Katsumi; Kato, Masana

1994-05-01

An experimental formula has been proposed to estimate the bending fatigue strength of carburized gears from the hardness and the residual stress. The derivation of the formula is briefly reviewed, and the effectiveness of the formula is demonstrated in this article. The comparison with many test results for carburized and shot-peened gears verifies that the formula is effective for the approximate estimation of the fatigue strength. The formula quantitatively shows a way of enhancing fatigue strength, i.e., the increase of hardness and residual stress at the fillet. The strength is enhanced about 300 MPa by an appropriate shot peening, and it can be improved still more by the surface removal by electropolishing.

Sangre, fetiche, ceguera: deseos y abrazos rotos

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José Luis Castro de Paz

2012-10-01

Full Text Available Segunda parte de la (hasta ahora oscura trilogía almodovariana sobre el deseo masculino, la “Mujer” objeto de ese deseo, y sus desoladores avatares (con Hable con ella [2002] y La piel que habito [2011], Los abrazos rotos constituye una de las cimas de la filmografía de Pedro Almodóvar, conjugando la reformulación de ciertos temas formales provenientes del cajón de formas fílmicas hitchcockiano –pero también, y aquí muy especialmente, del mejor cine español (Lorenzo Llobet-Gràcia– con una sutilísima e intransferible destilación formal. Una escritura que, partiendo de imágenes en cierta forma “alejadas del mundo” por saturación gráfica y metacinemato-gráfica, lleva el proceso a tal grado de abstracción que es capaz de (reactivarlas mediante la frotación de cada una con otras semejantes, alcanzando una inusitada potencia emocional para hablarnos de las heridas del mundo y del deseo, para volver a tocar la realidad perdida a través de una ostentosa y extravagante pero a la postre fructífera hipertrofia formalista.

Attaching Thermocouples by Peening or Crimping

Science.gov (United States)

Murtland, Kevin; Cox, Robert; Immer, Christopher

2006-01-01

Two simple, effective techniques for attaching thermocouples to metal substrates have been devised for high-temperature applications in which attachment by such conventional means as welding, screws, epoxy, or tape would not be effective. The techniques have been used successfully to attach 0.005- in. (0.127-mm)-diameter type-S thermocouples to substrates of niobium alloy C-103 and stainless steel 416 for measuring temperatures up to 2,600 F (1,427 C). The techniques are equally applicable to other thermocouple and substrate materials. In the first technique, illustrated in the upper part of the figure, a hole slightly wider than twice the diameter of one thermocouple wire is drilled in the substrate. The thermocouple is placed in the hole, then the edge of the hole is peened in one or more places by use of a punch (see figure). The deformed material at the edge secures the thermocouple in the hole. In the second technique a hole is drilled as in the first technique, then an annular relief area is machined around the hole, resulting in structure reminiscent of a volcano in a crater. The thermocouple is placed in the hole as in the first technique, then the "volcano" material is either peened by use of a punch or crimped by use of sidecutters to secure the thermocouple in place. This second technique is preferable for very thin thermocouples [wire diameter .0.005 in. (.0.127 mm)] because standard peening poses a greater risk of clipping one or both of the thermocouple wires. These techniques offer the following advantages over prior thermocouple-attachment techniques: . Because these techniques involve drilling of very small holes, they are minimally invasive . an important advantage in that, to a first approximation, the thermal properties of surrounding areas are not appreciably affected. . These techniques do not involve introduction of any material, other than the substrate and thermocouple materials, that could cause contamination, could decompose, or oxidize

Effect of Shot Peening on the Fatigue Strength of Automotive Tubular Stabilizer Bars DC 218

Directory of Open Access Journals (Sweden)

Wittek A.M.

2016-12-01

Full Text Available This paper concerns issues related to the development of designs of stabilizer bars for new motor vehicle models. It involves not only the designing of a stabilizer bar with the shape required by the manufacturer, but also the preparation of bending and heat treatment processes as well as the performance of strength and fatigue tests. In the prototype development phase, the simulations techniques (FEM may be used to assess the design. The article contains a detailed analysis of a stabilizer bar designated with the DC 218 VA symbol. Performed numerical strength and fatigue calculations showed that the developed stabilizer bar design with the desired shape did not achieve the required number of fatigue cycles. It was also proven at the test stand by testing a prototype stabilizer bar. Therefore, it was suggested to supplement the technological process with an additional shot peening operation whose main aim was to reduce the length of microcracks on the stabilizer bar’s surface. This effect was confirmed during comparative metallographic tests of not shot – peened and shot – peened stabilizer bars. After shot peening, the analysed stabilizer bar reached a fatigue strength which exceeded the limits set by the manufacturer.

Effects of Rayleigh damping, friction and rate-dependency on 3D residual stress simulation of angled shot peening

International Nuclear Information System (INIS)

Kim, Taehyung; Lee, Hyungyil; Hyun, Hong Chul; Jung, Sunghwan

2013-01-01

Highlights: ► We propose a 3D FE model to study peening residual stress involving angled shots. ► The FE model set with plastic shot are found to best match the X-ray diffraction data. ► The model provides 3D multi-shot impact FE solution with various incidence angles. - Abstract: In this study, we propose a 3D finite element (FE) model to study shot peening involving angled shots. Using the FE model for angled shot peening, we examine relationships with the residual stress introduced by shot peening of the factors such as the Rayleigh damping in the material, dynamic friction, and the rate dependency of the material and systematically integrate them with the FE model. The FE model is set with rigid shot, elastic shot, and plastic shot respectively. Plastic deformation of the shot is also explored with the FE model. The FE model is applied to study angled multi-shots. The FE results are verified with experimental data using X-ray diffraction (XRD). The FE model set with plastic shot are found to best match the XRD results validating accuracy of the 3D FE model properly integrated with the factors and plastically deformable shot ball. The proposed model will serve to simulate actual shot peening cases, which generally involve multi-shots with various incidence angles

Effect of shot peening on the residual stress and mechanical behaviour of low-temperature and high-temperature annealed martensitic gear steel 18CrNiMo7-6

DEFF Research Database (Denmark)

Yang, R.; Zhang, X.; Mallipeddi, D.

2017-01-01

A martensitic gear steel (18CrNiMo7-6) was annealed at 180 degrees C for 2h and at similar to 750 degrees C for 1h to design two different starting microstructures for shot peening. One maintains the original as-transformed martensite while the other contains irregular-shaped sorbite together...... with ferrite. These two materials were shot peened using two different peening conditions. The softer sorbite + ferrite microstructure was shot peened using 0.6 mm conditioned cut steel shots at an average speed of 25 m/s in a conventional shot peening machine, while the harder tempered martensite steel...

Evaluation of Surface Roughness by Image Processing of a Shot-Peened, TIG-Welded Aluminum 6061-T6 Alloy: An Experimental Case Study

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Anas M. Atieh

2018-05-01

Full Text Available Visual inspection through image processing of welding and shot-peened surfaces is necessary to overcome equipment limitations, avoid measurement errors, and accelerate processing to gain certain surface properties such as surface roughness. Therefore, it is important to design an algorithm to quantify surface properties, which enables us to overcome the aforementioned limitations. In this study, a proposed systematic algorithm is utilized to generate and compare the surface roughness of Tungsten Inert Gas (TIG welded aluminum 6061-T6 alloy treated by two levels of shot-peening, high-intensity and low-intensity. This project is industrial in nature, and the proposed solution was originally requested by local industry to overcome equipment capabilities and limitations. In particular, surface roughness measurements are usually only possible on flat surfaces but not on other areas treated by shot-peening after welding, as in the heat-affected zone and weld beads. Therefore, those critical areas are outside of the measurement limitations. Using the proposed technique, the surface roughness measurements were possible to obtain for weld beads, high-intensity and low-intensity shot-peened surfaces. In addition, a 3D surface topography was generated and dimple size distributions were calculated for the three tested scenarios: control sample (TIG-welded only, high-intensity shot-peened, and low-intensity shot-peened TIG-welded Al6065-T6 samples. Finally, cross-sectional hardness profiles were measured for the three scenarios; in all scenarios, lower hardness measurements were obtained compared to the base metal alloy in the heat-affected zone and in the weld beads even after shot-peening treatments.

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

Science.gov (United States)

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

2006-01-01

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

Eddy Current Nondestructive Residual Stress Assessment in Shot-Peened Nickel-Base Superalloys

International Nuclear Information System (INIS)

Blodgett, M.P.; Yu, F.; Nagy, P.B.

2005-01-01

Shot peening and other mechanical surface enhancement methods improve the fatigue resistance and foreign-object damage tolerance of metallic components by introducing beneficial near-surface compressive residual stresses and hardening the surface. However, the fatigue life improvement gained via surface enhancement is not explicitly accounted for in current engine component life prediction models because of the lack of accurate and reliable nondestructive methods that could verify the presence of compressive near-surface residual stresses in shot-peened hardware. In light of its frequency-dependent penetration depth, the measurement of eddy current conductivity has been suggested as a possible means to allow the nondestructive evaluation of subsurface residual stresses in surface-treated components. This technique is based on the so-called piezoresistivity effect, i.e., the stress-dependence of electrical resistivity. We found that, in contrast with most other materials, surface-treated nickel-base superalloys exhibit an apparent increase in electrical conductivity at increasing inspection frequencies, i.e., at decreasing penetration depths. Experimental results are presented to illustrate that the excess frequency-dependent apparent eddy current conductivity of shot-peened nickel-base superalloys can be used to estimate the absolute level and penetration depth of the compressive residual stress layer both before and after partial thermal relaxation

Effect of applied stress on the compressive residual stress introduced by laser peening

International Nuclear Information System (INIS)

Sumiya, Rie; Tazawa, Toshiyuki; Narazaki, Chihiro; Saito, Toshiyuki; Kishimoto, Kikuo

2016-01-01

Peening is the process which is able to be generated compressive residual stress and is known to be effective for preventing SCC initiation and improvement of fatigue strength. Laser peening is used for the nuclear power plant components in order to prevent SCC initiation. Although it is reported that the compressive residual stress decreases due to applied stresses under general operating condition, the change of residual stress might be large under excessive loading such as an earthquake. The objectives of this study are to evaluate the relaxation behavior of the compressive residual stress due to laser peening and to confirm the surface residual stress after loading. Therefore laser peened round bar test specimens of SUS316L which is used for the reactor internals of nuclear power plant were loaded at room temperature and elevated temperature and then surface residual stresses were measured by X-ray diffraction method. In the results of this test, it was confirmed that the compressive residual stress remained after applying uniform stress larger than 0.2% proof stress, and the effect of cyclic loading on the residual stress was small. The effect of applying compressive stress on the residual stress relaxation was confirmed to be less than that of applying tensile stress. Plastic deformation through a whole cross section causes the change in the residual stress distribution. As a result, the surface compressive residual stress is released. It was shown that the effect of specimen size on residual stress relaxation and the residual stress relaxation behavior in the stress concentration region can be explained by assumed stress relaxation mechanism. (author)

Development of fiber-delivered laser peening system to prevent stress corrosion cracking of reactor components

International Nuclear Information System (INIS)

Sano, Y.; Kimura, M.; Yoda, M.; Mukai, N.; Sato, K.; Uehara, T.; Ito, T.; Shimamura, M.; Sudo, A.; Suezono, N.

2001-01-01

The authors have developed a system to deliver water-penetrable intense laser pulses of frequency-doubled Nd:YAG laser through optical fiber. The system is capable of improving a residual stress on water immersed metal material remotely, which is effective to prevent the initiation of stress corrosion cracking (SCC) of reactor components. Experimental results showed that a compressive residual stress with enough amplitude and depth was built in the surface layer of type 304 stainless steel (SUS304) by irradiating laser pulses through optical fiber with diameter of 1 mm. A prototype peening head with miniaturized dimensions of 88 mm x 46 mm x 25 mm was assembled to con-firm the accessibility to the heat affected zone (HAZ) along weld lines of a reactor core shroud. The accessibility was significantly improved owing to the flexible optical fiber and the miniaturized peening head. The fiber delivered system opens up the possibility of new applications of laser peening. (author)

Microstructural evolution and mechanical properties of oil jet peened aluminium alloy, AA6063-T6

International Nuclear Information System (INIS)

Arun Prakash, N.; Gnanamoorthy, R.; Kamaraj, M.

2010-01-01

Grain size refinement by severe surface plastic deformation is one way of improving the surface properties. This paper describes the microstructural evolution due to severe surface plastic deformation by oil jet peening in aluminium alloy, AA6063-T6. Detail characterization of the treated surfaces using X-ray diffraction analysis and transmission electron microscopy revealed the formation of submicron size grains at and near the surface. The nozzle-traveling velocity decides the peening intensity and coverage and affects the surface properties. The specimen peened at low nozzle-traveling velocity exhibited an ultrafine grain size (∼210 nm) with high surface hardness (∼0.88 GPa), compressive residual stress (-102 ± 7 MPa) and dislocation density. The hardness is high at the surface and the depth of hardened layer is ∼400 μm. Formation of high-density dislocations and associated grain refinement resulted in increased surface hardness. Presence of surface modified layer will be beneficial in improving the fatigue and tribo behavior.

Thermal Effects on Thin Laser-Peened Ferritic-Martensitic Samples

International Nuclear Information System (INIS)

Caro, M; Zalesky, T; Hosemann, P; El-dasher, B S; Halsey, W G; Stuart, B

2007-01-01

Laser peening is emerging as a promising technique to improve the corrosion resistance of cladding material candidates for lead-cooled fast reactors (LFRs). The challenge is in the performance capability of ∼1 mm-thick fuel-pin cladding. Ferritic-martensitic (F/M) steels are foreseen as possible candidates that stand severe conditions of high dose (150 dpa), and high temperature (∼500-600 C) under the corrosive environments of molten lead or lead-bismuth. In this paper, we present the results of experiments carried on laser peened (LP) samples of F/M steels HT9, T91, EP823, as well as the austenitic material 316 L. The samples underwent a thermal treatment in an oven at 520 C, and XRD compressive stress results indicate that the F/M samples do not retain the residual stress after 2 weeks of heat treatment. The corrosion behavior in flowing lead-bismuth eutectic (LBE) at 535 C has been investigated as well. Also, irradiation experiments of LP samples to a maximum dose of ∼10 dpa are foreseen

Finite element modelling of shot peening process: Prediction of the compressive residual stresses, the plastic deformations and the surface integrity

International Nuclear Information System (INIS)

Frija, M.; Hassine, T.; Fathallah, R.; Bouraoui, C.; Dogui, A.

2006-01-01

This paper presents a numerical simulation of the shot peening process using finite element method. The majority of the controlling parameters of the process have been taken into account. The shot peening loading has been characterised by using energy equivalence between the dynamic impact and a static indentation of a peening shot in the treated surface. The behaviour of the subjected material is supposed to be elastic plastic with damage. An integrated law of the damage proposed by Lemaitre and Chaboche has been used. The proposed model leads to obtain the residual stress, the plastic deformation profiles and the surface damage. An application on a shot peened Ni-based super alloy Waspaloy has been carried out. The comparison of the residual stresses, obtained by X-ray diffraction method and by finite element calculation, shows a good correlation. The in-depth profile of the plastic deformations and the superficial damage values are in good agreement with the experimental observations

The effect of Laser Shock Peening on Fatigue Life Using Pure Water and Hydrofluoric Acid As a Confining Layer of Al – Alloy 7075-T6

Directory of Open Access Journals (Sweden)

Shaker Sakran Hassan

2018-01-01

Full Text Available Laser shock peening (LSP is deemed as a deep-rooted technology for stimulating compressive residual stresses below the surface of metallic elements. As a result, fatigue lifespan is improved, and the substance properties become further resistant to wear and corrosion. The LSP provides more unfailing surface treatment and a potential decrease in microstructural damage. Laser shock peening is a well-organized method measured up to the mechanical shoot peening. This kind of surface handling can be fulfilled via an intense laser pulse focused on a substantial surface in extremely shorter intervals. In this work, Hydrofluoric Acid (HF and pure water as a coating layer were utilized as a new technique to improve the properties and to harden the treated surface of the Al -alloy 7075-T6. Fatigue life by means of laser peened workpieces was improved to 154.3%, 9.78%, respectively, for Hydrofluoric (HF and pure water compared to un-peened specimens. And the outcomes of Vickers hardness test for laser shock peening with acid and pure water as well as un-peened specimens were 165.2HV30, 143.95HV30 and 134.7HV30, respectively showed a significant improvement in the hardness property.

Shot-Peening Effect on High Cycling Fatigue of Al-Cu Alloy

Science.gov (United States)

Fouad, Yasser; Metwally, Mostafa El

2013-12-01

The present work was aimed at evaluating the effects of shot-peening on the high cycle fatigue performance of the age-hardening aircraft alloy Al 2024 at different almen intensities. Shot-peening to full coverage (100 pct) was performed using spherically conditioned cut wire (SCCW 14) with an average shot size of 0.36 mm and at almen intensities of 0.1, 0.2, and 0.3 mmA. After applying the various mechanical surface treatments, the changes in the surface and near-surface layer properties such as microhardness, residual stress-depth profiles, and surface roughness were determined. The microhardness, surface roughness, and the residual stresses increased proportionally with the almen intensity. Electropolitically polished conditions were used as reference in the mechanically surface treated specimens. A significant improvement was seen in the fatigue performance of the 0.1 mmA.

Aneurisma de artéria ilíaca interna roto: relato de caso Ruptured internal iliac artery aneurysm: case report

Directory of Open Access Journals (Sweden)

Cristina Toledo Afonso

2009-03-01

Full Text Available Aneurismas isolados da artéria ilíaca interna são raros, acometem 0,1% da população e correspondem a 1% dos aneurismas aorto-ilíacos. Na maioria das vezes, os pacientes são assintomáticos, mas podem apresentar dor abdominal, massa pulsátil no hipogástrio ou na fossa ilíaca, sintomas compressivos urinários, gastrointestinais ou neurológicos. Podem ocasionar quadro de abdome agudo, principalmente quando há ruptura. O diagnóstico precoce dos aneurismas isolados de artéria ilíaca interna é incomum, sendo identificados quando mais volumosos ou rotos, o que aumenta significativamente sua morbimortalidade e torna seu prognóstico mais reservado. Dessa forma, representam um desafio terapêutico. A ligadura cirúrgica tem sido o tratamento mais comum, entretanto a cirurgia endovascular tem mostrado bons resultados, inclusive nos aneurismas rotos. É relatado caso de aneurisma de artéria ilíaca interna isolado roto diagnosticado durante laparotomia para abordagem de abdome agudo.Isolated internal iliac artery aneurysms are rare. They affect 0.1% of the population, and account for 1% of aortoiliac aneurysms. Patients are mostly asymptomatic, yet they can have abdominal pain, pulsatile mass in the hypogastrium or iliac fossa, or urinary, gastrointestinal or neurological compressive symptoms. Such aneurysms are likely to course with an acute abdomen, especially when ruptured. Early diagnosis of isolated internal iliac artery aneurysms is difficult, as they are more easily detected when larger or ruptured, which significantly raises their morbidity and mortality rate and determines a poor prognosis. Therefore, they are a therapeutic challenge. Surgical ligation has been the most common treatment; however, the endovascular approach has presented good outcomes, even in the event of ruptured aneurysms. A case of ruptured isolated iliac artery aneurysm diagnosed during a laparotomy (acute abdomen approach is reported.

Influence of plasma molybdenizing and shot-peening on fretting damage behavior of titanium alloy

Energy Technology Data Exchange (ETDEWEB)

Tang, Chang-bin, E-mail: tcbtop@126.com [School of Metallurgy and Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi 710055 (China); Institute of Corrosion and Protection, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Liu, Dao-xin, E-mail: liudaox@nwpu.edu.cn [Institute of Corrosion and Protection, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Tang, Bin [Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan Shanxi 030024 (China); Zhang, Xiao-hua [Institute of Corrosion and Protection, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Qin, Lin [Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan Shanxi 030024 (China); Liu, Cheng-song [Institute of Corrosion and Protection, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China)

2016-12-30

Highlights: • Plasma molybdenizing increases FW resistance of Ti6Al4V, but reduces its FF life. • Shot-peened plasmamolybdenizing surface enhances FW and FF resistance of Ti6Al4V. • Combined treatment yields low surface-roughness & high hardness gradient distribution. • Combined treatment yields beneficial residual compressive stress & good toughness. • Anti-wear & -fatigue performance improvements for surface engineering applications. - Abstract: Effect of plasma molybdenizing and shot-peening on fretting wear and fretting fatigue behaviors of Ti6Al4V alloy was investigated. The plasma molybdenized layer composed of a dense molybdenum deposition layer and a Mo–Ti solid–solution layer can increase surface hardness by 2.8 times and cause its volume loss by fretting wear to decrease to 1/14 compared with that of the substrate. Plasma molybdenized treatment results in a significant decrease in resistance of the substrate to fretting fatigue. It is ascribed that the molybdenized layer with high hardness yields a low toughness, and its high surface roughness leads to a micro-notched effect. However, proper combination plasma molybdenizing and subsequent shot-peening may enhance the simultaneous fretting fatigue and fretting wear resistance of Ti6Al4V significantly, which can decrease the fretting wear volume loss to 1/27, and may increase the fretting fatigue life by more than 69 times. A synergistic improvement in fretting fatigue of the titanium alloy by combining surface alloying with shot-peening can be achieved. The results indicate that a beneficial residual compressive stress distribution, high surface hardness with suitable hardness gradient distribution, good apparent toughness, relatively low surface roughness, and excellent surface integrity are achieved.

Conductivity Profile Determination by Eddy Current for Shot Peened Superalloy Surfaces Toward Residual Stress Assessment

International Nuclear Information System (INIS)

Shen, Y.; Lo, C. C. H.; Frishman, A. M.; Lee, C.; Nakagawa, N.

2007-01-01

This paper describes an eddy current model-based method for inverting near-surface conductivity deviation profiles of surface treated materials from swept-high frequency eddy current (SHFEC) data. This work forms part of our current research directed towards the development of an electromagnetic nondestructive technique for assessing residual stress of shot-peened superalloy components. The inversion procedure is based on the use of a parameterized function to describe the near-surface conductivity as a function of depth for a shot-peened surface, and the laterally uniform multi-layer theory of Cheng, Dodd and Deeds to calculate the resulting coil impedance deviations. The convergence of the inversion procedure has been tested against synthesized eddy current data. As a demonstration, the conductivity deviation profiles of a series of Inconel 718 specimens, shot peened at various Almen intensities, have been obtained by inversion. Several consistency tests were conducted to examine the reliability of the inverted conductivity profiles. The results show that conductivity deviation profiles can be reliably determined from SHFEC data within the accuracy of the current measurement system

EDF (Electricite de France) feedback shot-peening on feedwater plants working to 360 0 C: prediction correlation and follow-up of thermal stresses relaxation

International Nuclear Information System (INIS)

Gauchet, J.P.

1995-01-01

This study predicts life duration of shot-peening effect and finally to allow the plant operator to prepare routine stopping, considering the following four steps have been: the shot-peening parameters must been carefully chosen and implementation must be reliable and perfectly reproducible; the residual stresses and cold working state checked by X-ray diffraction; the EDF feedback on different steam-water system components working at around-300 0 C and repaired by shot-peening, like feed heater water boxes, water tanks and vessels, steam pipes; a program, carried out on a feedwater tank repaired by welding and hot-peening and working at 360 0 C, on the correlation between expected and effective results. (author). 7 refs., 3 figs., 1 tab

Effect of shot peening treatment in the behavior of residual stress in duplex stainless steel during medium cycle fatigue; Efeito do tratamento de shot peening no comportamento das tensoes residuais em aco inoxidavel duplex durante fadiga de medio ciclo

Energy Technology Data Exchange (ETDEWEB)

Pedrosa, Peter D.S.; Rebello, Joao Marcos A. [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEMM/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Metalurgica e de Materiais; Fonseca, Maria P. Cindra, E-mail: mcindra@vm.uff.b [Universidade Federal Fluminense (PGMEC/UFF), Niteroi, RJ (Brazil). Escola de Engenharia. Programa de Pos-Graduacao em Engenharia Mecanica

2010-07-01

The lifetime of duplex stainless steel parts experiencing cyclic fatigue is directly influenced by the residual stresses present in the ferrite and austenite phases. The motivation for this work was to analyze the behaviour of the residual stresses fields introduced by shot peening treatment in both phases, in the sample surface as in the subsurface layers, in low fatigue cycles, using the X-rays diffraction technique. The results shows that the compressive residual stresses introduced by the shot peening treatment in both phases improved fatigue life of the material. However, the cyclical loads produce partial or total relief in these residual stresses fields. It was verified that the shot peening process induced the formation of microcracks only in the ferrite phase. The largest variations in the total compressive residual stresses fields also occurred in this phase. The samples surfaces were analyzed by scanning electron microscopy. (author)

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

International Nuclear Information System (INIS)

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

2014-01-01

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

Corrosion Control of Alloy 690 by Shot Peening and Electropolishing under Simulated Primary Water Condition of PWRs

Directory of Open Access Journals (Sweden)

Kyung Mo Kim

2015-01-01

Full Text Available This work clarifies the effect of surface modifications on the corrosion rate of Alloy 690, a nickel-based alloy for steam generator tubes, under the simulated test conditions of the primary water chemistry in nuclear power plants. The surface stress was modified by the shot peening and electropolishing methods. The shot peening treatment was applied using ceramic beads with different intensities by varying the air pressure and projection angle. The corrosion rate was evaluated by gravimetric analysis and the surface was analyzed by scanning electron microscopy (SEM. The corrosion rate of Alloy 690 was evaluated from the influence of the stress state on the metal surface. Based on the observation of the surface after the corrosion test, the oxide composition and its structure were affected by the surface modifications. The corrosion behavior of Alloy 690 was distinguished by the shot peening intensity on the surface, and additional electropolishing was effective at reducing the dissolution of nickel ions from the metal surface.

Finite Element Simulation of Shot Peening: Prediction of Residual Stresses and Surface Roughness

Science.gov (United States)

Gariépy, Alexandre; Perron, Claude; Bocher, Philippe; Lévesque, Martin

Shot peening is a surface treatment that consists of bombarding a ductile surface with numerous small and hard particles. Each impact creates localized plastic strains that permanently stretch the surface. Since the underlying material constrains this stretching, compressive residual stresses are generated near the surface. This process is commonly used in the automotive and aerospace industries to improve fatigue life. Finite element analyses can be used to predict residual stress profiles and surface roughness created by shot peening. This study investigates further the parameters and capabilities of a random impact model by evaluating the representative volume element and the calculated stress distribution. Using an isotropic-kinematic hardening constitutive law to describe the behaviour of AA2024-T351 aluminium alloy, promising results were achieved in terms of residual stresses.

El cine en el cine: Los abrazos rotos (Pedro Almodóvar, 2009

Directory of Open Access Journals (Sweden)

Pedro Poyato

2012-10-01

Full Text Available El cine en el cine, tema recurrente en la filmografía de Pedro Almodóvar, protagoniza también Los abrazos rotos, película que contiene en su interior otra titulada Chicas y maletas. Pero las imágenes de esta segunda película, trasunto de otra anterior del propio Almodóvar, Mujeres al borde un ataque de nervios, coexisten con las de un documental sobre su rodaje. El resultado es una proliferación de imágenes segundas que, incorporadas según una estructura en abismo, el filme va a conjugar de múltiples y variadas maneras. El presente trabajo trata de dar cuenta de la génesis, funcionamiento y declinación de estas imágenes segundas y de los sentidos que de ello emanan.

Residual stress relaxation due to fretting fatigue in shot peened surfaces of Ti-6Al-4V

International Nuclear Information System (INIS)

Martinez, S.A.; Blodgett, M.P.; Mall, S.; Sathish, S.; Namjoshi, S.

2003-01-01

Fretting fatigue occurs at locations where the materials are sliding against each other under load. In order to enhance the fatigue life under fretting conditions the surface of the component is shot peened. In general, the shot peening process produces a compressive stress on the surface of the material, thereby increasing the resistance of the material to crack initiation. This paper presents the relaxation of residual stress caused during fretting fatigue. X-ray diffraction has been utilized as the method to measure residual stress in fretting fatigued samples of Ti-6Al-4V

Investigation of Mechanical, Microstructural and Corrosion behaviour of Titanium subjected to Laser Peening with and without Ablation

Science.gov (United States)

Ranjith Kumar, G.; Sowmya Joshi, K.; Rajyalakshmi, G.; Kalainathan, S.; Prabhakaran, S.

2018-02-01

Present competitive world is looking for Components with high strength and fatigue resistance finding their applications in aerospace, turbine parts and especially bio-medical devices with high bio-compatibility. Advanced surface engineering techniques are required to produce parts of higher complexities and desirable surface qualities. Laser peening stood first in a row of all various surface treatments of metallic component. This paper discusses about the mechanical properties like hardness and roughness then the surface morphology and the corrosion behaviour of the laser peened titanium samples with and without coating.

Laser Shot Peening Final Report CRADA No. TC-02059-03

Energy Technology Data Exchange (ETDEWEB)

Stuart, B. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hackel, L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-09-27

This was a collaborative effort between The Regents of the University of California, Lawrence Livermore National Laboratory (LLNL) and Metal Improvement Company, Inc. (MIC), to further develop the laser shot peening technology. This project had an emphasis on laser development and government and military applications including DOE’s natural gas and oil technology program (NGOTP), Yucca Mountain Project (YMP), F-22 Fighter, etc.

Compound technology of manufacturing and multiple laser peening on microstructure and fatigue life of dual-phase spring steel

Energy Technology Data Exchange (ETDEWEB)

Prabhakaran, S., E-mail: spkaran.kmd@gmail.com; Kalainathan, S., E-mail: kalainathan@yahoo.com

2016-09-30

The present work proposes an advanced double quenching and tempering heat treatment based laser surface modification process of dual-phase spring steel. Multiple laser peening without coating process utilized the decarburized surface as the protective layer for the further cold working process. The electron backscattering diffraction analysis on crystallographic orientation of individual grains and phase map exhibits a perfect dual-phase steel. Also, the high resolution transmission electron microscopic study explains the high strain induced microstructural grain refinement features and plastic deformation behaviors. The laser peening technique taking an advantage that it induces a large and high magnitude compressive residual stress with good thermal stability. The micro and nano-hardness profile provides better surface and sub-surface mechanical properties. The controlled average surface roughness is achieved in this course of work. The stress-strain characteristics on tensile properties are analyzed through the pre-fatigued specimens. The fully reversed high cycle fatigue test indicates that the current laser peening has substantially improves the fatigue life of the specimens.

Effect of shot peening treatment in the behavior of residual stress in duplex stainless steel during medium cycle fatigue

International Nuclear Information System (INIS)

Pedrosa, Peter D.S.; Rebello, Joao Marcos A.; Fonseca, Maria P. Cindra

2010-01-01

The lifetime of duplex stainless steel parts experiencing cyclic fatigue is directly influenced by the residual stresses present in the ferrite and austenite phases. The motivation for this work was to analyze the behaviour of the residual stresses fields introduced by shot peening treatment in both phases, in the sample surface as in the subsurface layers, in low fatigue cycles, using the X-rays diffraction technique. The results shows that the compressive residual stresses introduced by the shot peening treatment in both phases improved fatigue life of the material. However, the cyclical loads produce partial or total relief in these residual stresses fields. It was verified that the shot peening process induced the formation of microcracks only in the ferrite phase. The largest variations in the total compressive residual stresses fields also occurred in this phase. The samples surfaces were analyzed by scanning electron microscopy. (author)

Laser peening applications for next generation of nuclear power facilities

International Nuclear Information System (INIS)

Rankin, J.; Truong, C.; Walter, M.; Chen, H.-L.; Hackel, L.

2008-01-01

Generation of electricity by nuclear power can assist in achieving goals of reduced greenhouse gas emissions. Increased safety and reliability are necessary attributes of any new nuclear power plants. High pressure, hot water and radiation contribute to operating environments where Stress Corrosion Cracking (SCC) and hydrogen embrittlement can lead to potential component failures. Desire for improved steam conversion efficiency pushes the fatigue stress limits of turbine blades and other rotating equipment. For nuclear reactor facilities now being designed and built and for the next generations of designs, laser peening could be incorporated to provide significant performance life to critical subsystems and components making them less susceptible to fatigue, SCC and radiation induced embrittlement. These types of components include steam turbine blades, hubs and bearings as well as reactor components including cladding material, housings, welded assemblies, fittings, pipes, flanges, vessel penetrations, nuclear waste storage canisters. Laser peening has proven to be a commercial success in aerospace applications and has recently been put into use for gas and steam turbine generators and light water reactors. An expanded role for this technology for the broader nuclear power industry would be a beneficial extension. (author)

Laser shock peening of steam turbine blade for enhanced service life

Indian Academy of Sciences (India)

2014-02-13

Feb 13, 2014 ... Fretting-fatigue is an important factor influencing service life of turbine blades. The present paper describes laser shock peening of potential crack nucleation site in the root region of steam turbine blade for its enhanced service life. The experimental study, performed with an in-house developed 2.5 J/7 ns ...

Effects of shot-peening and atmospheric-pressure plasma on aesthetic improvement of Ti-Nb-Ta-Zr alloy for dental applications

Science.gov (United States)

Miura-Fujiwara, Eri; Suzuki, Yuu; Ito, Michiko; Yamada, Motoko; Matsutake, Sinpei; Takashima, Seigo; Sato, Hisashi; Watanabe, Yoshimi

2018-01-01

Ti and Ti alloys are widely used for biomedical applications such as artificial joints and dental devices because of their good mechanical properties and biochemical compatibility. However, dental devices made of Ti and Ti alloys do not have the same color as teeth, so they are inferior to ceramics and polymers in terms of aesthetic properties. In a previous study, Ti-29Nb-13Ta-4.6Zr was coated with a white Ti oxide layer by heat treatment to improve its aesthetic properties. Shot-peening is a severe plastic deformation process and can introduce a large shear strain on the peened surface. In this study, the effects of shot-peening and atmospheric-pressure plasma on Ti-29Nb-13Ta-4.6Zr were investigated to form a white layer on the surface for dental applications.

Residual stresses under quasi-static and cyclic loading in shot peened Inconel 718

Energy Technology Data Exchange (ETDEWEB)

Hoffmeister, Juergen; Schulze, Volker [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Inst. for Applied Materials; Hessert, Roland; Koenig, Gerhard [MTU Aero Engines, Munich (Germany)

2012-01-15

The residual stress state induced by shot peening should be taken into account in the dimensioning of turbine components. Understanding the changes in the residual stress state caused by the application of quasi-static and cyclic loads is a prerequisite. In order to describe the residual stress state after quasi-static loading, several different shot peened Inconel 718 specimens were loaded isothermally up to specific tensile loadings. To analyze the residual stress state after cyclic loading, isothermal low cycle fatigue tests were performed. These tests were stopped after a defined number of cycles. Finally, after the specimens had been subjected to different loads, the surface residual stresses and - for special loadings - the residual stress depth distributions were determined experimentally by using X-ray diffraction. The surface - core model was adapted so that the complete residual stress depth distribution after quasi-static and cyclic loading can now be described. (orig.)

A study on the corrosion characteristics of gear steel by shot peening

International Nuclear Information System (INIS)

Kang, Jin Shik; Kim, Tae Hyung; Cheong, Seong Kyun; Yoon, Jong Ku; Lee, Seung Ho

2001-01-01

The surface treatment technique to increase corrosion resistance is very important in mechanical components of structures. Therefore, this paper investigates the effects of shot peening on the corrosion resistance of SCM 420steel. The results show that the surface compressive residual stress largely increases, which cause the increase of corrosion resistance

THE EFFECT OF THE CONDITIONS OF SHOT PEENING THE INCONEL 718 NICKEL ALLOY ON THE GEOMETRICAL STRUCTURE OF THE SURFACE

Directory of Open Access Journals (Sweden)

Kazimierz Zaleski

2017-06-01

Full Text Available The article presents the research results of roughness and topography of the surface of Inconel 718 nickel alloy after shot peening. Evaluation of stereometric properties of the surface layer of the examined material was performed based on the amplitude, height and Abbott-Firestone curve parametres. The shot peening was carried out on the impulse shot peening stand. The impact energy Ej, distance between the traces xs and the ball diameter dk were changed in the range: Ej = 60 ÷ 240 mJ, xs = 0,15 ÷ 0,5 mm, dk = 3,95 ÷ 12,45 mm. The T8000 RC 120-140 device of the Hommel-Etamic company, along with the software, was used for measuring the surface roughness and for determining the material bearing curve. As a result of the machin-ing, the surface roughness was reduced and the selected functional parameters were improved.

A coupled creep plasticity model for residual stress relaxation of a shot-peened nickel-based superalloy

Science.gov (United States)

Buchanan, Dennis J.; John, Reji; Brockman, Robert A.; Rosenberger, Andrew H.

2010-01-01

Shot peening is a commonly used surface treatment process that imparts compressive residual stresses into the surface of metal components. Compressive residual stresses retard initiation and growth of fatigue cracks. During component loading history, shot-peened residual stresses may change due to thermal exposure, creep, and cyclic loading. In these instances, taking full credit for compressive residual stresses would result in a nonconservative life prediction. This article describes a methodical approach for characterizing and modeling residual stress relaxation under elevated temperature loading, near and above the monotonic yield strength of INI 00. The model incorporates the dominant creep deformation mechanism, coupling between the creep and plasticity models, and effects of prior plastic strain to simulate surface treatment deformation.

Laser shock peening of Ti-17 titanium alloy: Influence of process parameters

Energy Technology Data Exchange (ETDEWEB)

Cellard, C.; Retraint, D.; Francois, M. [University of Technology of Troyes (UTT), Charles Delaunay Institute, LASMIS, UMR CNRS 6279, 12 Rue Marie Curie, BP2060, 10010 Troyes Cedex (France); Rouhaud, E., E-mail: rouhaud@utt.fr [University of Technology of Troyes (UTT), Charles Delaunay Institute, LASMIS, UMR CNRS 6279, 12 Rue Marie Curie, BP2060, 10010 Troyes Cedex (France); Le Saunier, D. [SNECMA Evry - Corbeil, Route Henry Auguste Desbrueres, 91003 Evry (France)

2012-01-15

Highlights: Black-Right-Pointing-Pointer Laser shock peening parameters studied through a design of experiments. Black-Right-Pointing-Pointer Laser fluence, pulse duration, number of impacts and sample thickness are studied. Black-Right-Pointing-Pointer The observed work hardening is low, the roughness is lightly affected. Black-Right-Pointing-Pointer A significant part of hardness increase is due to compressive residual stresses. Black-Right-Pointing-Pointer High tensile residual stresses can appear on thin laser shocked specimens. - Abstract: The influence of the process parameters of laser shock peening was investigated on specimens made of an aeronautic titanium alloy: Ti-5Al-2Sn-2Zr-4Cr-4Mo (Ti-17). In order to quantify the effect of relevant process parameters, an experimental design was carried out. It is based on a full factorial design with four factors (laser fluence, pulse duration, number of impacts and thickness of the sample) and two levels for each factor. The process is characterised with the following variables: the depth of the impacts, the roughness of the treated surface, the hardening of the material (itself evaluated with the hardness and X-ray diffraction peak width), the residual stresses left in the sample and the global curvature of the sample. It is found that all the parameters have an influence on the residual stresses and that laser shock peening has no influence on roughness and low influence on work-hardening. The variables are then analysed in order to evaluate correlations. The increase in hardness is found to be essentially due to compressive residual stresses, cold work-hardening having only a small effect. In thin specimens, the stress redistribution due to self-equilibrium leads to tensile residual stresses at the treated surface and to large deformations of the specimens.

Dark field differential dynamic microscopy enables accurate characterization of the roto-translational dynamics of bacteria and colloidal clusters

Science.gov (United States)

Cerbino, Roberto; Piotti, Davide; Buscaglia, Marco; Giavazzi, Fabio

2018-01-01

Micro- and nanoscale objects with anisotropic shape are key components of a variety of biological systems and inert complex materials, and represent fundamental building blocks of novel self-assembly strategies. The time scale of their thermal motion is set by their translational and rotational diffusion coefficients, whose measurement may become difficult for relatively large particles with small optical contrast. Here we show that dark field differential dynamic microscopy is the ideal tool for probing the roto-translational Brownian motion of anisotropic shaped particles. We demonstrate our approach by successful application to aqueous dispersions of non-motile bacteria and of colloidal aggregates of spherical particles.

Microstructural changes due to laser peening in modified 9Cr-1Mo steel subjected to creep damage at 823K and 923K in air

International Nuclear Information System (INIS)

Nakasone, Yuji; Kizuki, Yuta; Suzuki, Hayao; Minowa, Takuya

2013-01-01

The present study has investigated microstructural changes due to laser peening in modified 9Cr-1Mo steel subjected to creep. The EBSD or Electron Backscatter Diffraction studies have been made on round-bar type specimens creeping at applied stresses of 230 and 240 MPa at 823 K and 105 MPa at 923K in air. Prior to the creep tests, laser peening was applied to specimens at laser power of 8.4-22GW/cm 2 per pulse in water. Microstructural change in each specimen after its creep test was investigated by EBSD/SEM. The EBSD/SEM analyses revealed that the laser peening treatment makes creep rupture time longer and it reveals local misorientation value for rupture. (author)

Analytic examination of mechanism for compressive residual stress introduction with low plastic strain using peening

International Nuclear Information System (INIS)

Ishibashi, Ryo; Hato, Hisamitsu; Miyazaki, Katsumasa; Yoshikubo, Fujio

2016-01-01

Our goal for this study was to understand the cause of the differences in surface properties between surfaces processed using water jet peening (WJP) and shot peening (SP) and to examine the compressive residual stress introduction process with low plastic strain using SP. The dynamic behaviors of stress and strain in surfaces during these processes were analyzed through elasto-plastic calculations using a finite-element method program, and the calculated results were compared with measured results obtained through experiments. Media impacting a surface results in a difference in the hardness and microstructure of the processed surface. During SP, a shot deforms the surface locally with stress concentration in the early stages of the impact, while shock waves deform the surface evenly throughout the wave passage across the surface during WJP. A shot with a larger diameter creates a larger impact area on the surface during shot impact. Thus, SP with a large-diameter shot suppresses the stress concentration under the same kinetic energy condition. As the shot diameter increases, the equivalent plastic strain decreases. On the other hand, the shot is subject to size restriction since the calculated results indicate the compressive residual stress at the surface decreased and occasionally became almost zero as the shot diameter increased. Thus, compressive residual stress introduction with low plastic strain by using SP is considered achievable by using shots with a large diameter and choosing the appropriate peening conditions. (author)

Surface mechanical property and residual stress of peened nickel-aluminum bronze determined by in-situ X-ray diffraction

Science.gov (United States)

Wang, Chengxi; Jiang, Chuanhai; Zhao, Yuantao; Chen, Ming; Ji, Vincent

2017-10-01

As one of the most important surface strengthening method, shot peening is widely used to improve the fatigue and stress corrosion crack resistance of components by introducing the refined microstructure and compressive residual stress in the surface layer. However, the mechanical properties of this thin layer are different from the base metal and are difficult to be characterized by conventional techniques. In this work, a micro uniaxial tensile tester equipped with in-situ X-ray stress analyzer was employed to make it achievable on a nickel-aluminum bronze with shot peening treatment. According to the equivalent stress-strain relationship based on Von Mises stress criterion, the Young's modulus and yield strength of the peened layer were calculated. The results showed that the Young's modulus was the same as the bulk material, and the yield strength corresponding to the permanent plastic strain of 0.2% was increased by 21% after SP. But the fractographic analysis showed that the fracture feature of the surface layer was likely to transform from the dimple to the cleavage, indicating the improved strength might be attained at the expense of ductility. The monotonic and cyclic loading were also performed via the same combined set-up. In addition, the specific relaxation behavior of compressive residual stress was quantified by linear logarithm relationship between residual stress and cycle numbers. It was found that the compressive residual stress mainly relaxed in the first few cycles, and then reached steady state with further cycles. The relaxation rate and the stable value were chiefly depended on the stress amplitude and number of cycles. The retained residual stress kept in compressive under all given applied stress levels, suggesting that the shot peening could introduce a more stable surface layer of compressive residual stress other than the elevated strength of nickel-aluminum bronze alloy.

Effects of static strain aging on residual stress stability and alternating bending strength of shot peened AISI 4140

Energy Technology Data Exchange (ETDEWEB)

Menig, R.; Schulze, V.; Voehringer, O. [Inst. fuer Werkstoffkunde 1, Univ. Karlsruhe (TH), Karlsruhe (Germany)

2002-07-01

Increases of residual stress stability and alternating bending strength of shot peened AISI 4140 are obtained by successive annealing treatments. This is caused by static strain aging effects, which lead to pinning of dislocations by carbon atoms and very small carbides. It will be shown that by well directed annealing of a quenched and tempered AISI 4140 it is possible to maximize the positive effects of static strain aging, without causing extended thermal residual stress relaxation. The amount of yield stress increases caused by static strain aging is quantified using tensile tests. Static strain aging is also found to be responsible for an increase of the quasi static and cyclic surface yield strength present after shot peening. (orig.)

NIMONIC 263 microstructure and surface characterization after laser shock peening

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P. Drobnjak

2015-07-01

Full Text Available The Laser Shock Peening (LSP is applied to the surface of Nimonic 263 alloy. The changes in microstructure and surface topography are observed and analyzed by Scanning Electron Microscopy (SEM, profilometer and microhardness tester. Various laser regimes are chosen which provoke effects of both mechanical and thermo-mechanical treatments of the sample surface. The optimal process parameters, that result in the finest microstructure, smooth and clean surface, are determined. Some wanted and unwanted phases leading to the crack formation are observed.

Microstructural variation through weld thickness and mechanical properties of peened friction stir welded 6061 aluminum alloy joints

Energy Technology Data Exchange (ETDEWEB)

Abdulstaar, Mustafa A., E-mail: mustafa.abdulstaar@gmail.com [Institute of Material Science and Engineering, Clausthal University of Technology, Agricolastr. 6, 38678 Clausthal-Zellerfeld (Germany); Al-Fadhalah, Khaled J. [Department of Mechanical Engineering, College of Engineering & Petroleum, Kuwait University, P.O. Box 5969, Safat 13060 (Kuwait); Wagner, Lothar [Institute of Material Science and Engineering, Clausthal University of Technology, Agricolastr. 6, 38678 Clausthal-Zellerfeld (Germany)

2017-04-15

The current study examined the effect of microstructure variation on the development of mechanical properties in friction stir welded joints of 6061-T6 aluminum alloy, which were subsequently processed by shot peening (SP). Following to FSW, fatigue specimens were extracted perpendicularly to the welding direction. Surface Skimming to 0.5 mm from crown and root sides of the joint was made and SP was later applied on the two sides using ceramic shots of two different Almen intensities of 0.18 mmA and 0.24 mmA. Microstructural examination by electron back scattered diffraction (EBSD) indicated variation in the grain refinement of the weld zone, with coarsest grains (5 μm) at the crown side and finest grains (2 μm) at the root side. Reduction of microhardness to 60 HV occurred in the weld zone for samples in FSW condition. Application of SP promoted significant strain hardening at the crown side, with Almen intensities of 0.24 mmA providing maximum increase in microhardness to 120 HV. On the contrary, only a maximum microhardness of 75 HV was obtained at the root side. The difference in strain hardening capability at the two sides was strongly dependent on grain size. The two Almen intensities produced similar distribution of compressive residual stresses in the subsurface regions that led to enhance the fatigue strength to the level of base metal for N ≥ 10{sup 5} cycles. Yet, the increase in fatigue strength was more pronounced with increasing Almen intensity to 0.24 mmA, demonstrating further enhancement by strain hardening. - Highlights: • Grain refinement was observed after friction stir welding of AA 6061-T6. • Reduction in microhardness and fatigue strength were obtained after welding. • Variation in grain refinement led to different hardening behavior after peening. • Shot peening induced beneficial compressive residual stresses. • Shot peening and surface skimming markedly improved the fatigue performance.

Influence of laser peening on the tensile strength and impact toughness of dissimilar welds of Inconel 625 and UNS S32205

Energy Technology Data Exchange (ETDEWEB)

Ramkumar, K. Devendranath, E-mail: ramdevendranath@gmail.com [School of Mechanical Engineering, VIT University, Vellore 632014 (India); Kumar, P. Siva Goutham; Krishna, V. Radha; Chandrasekhar, Aditya; Dev, Sidharth; Abraham, Winston Sunny [School of Mechanical Engineering, VIT University, Vellore 632014 (India); Prabhakaran, S.; Kalainathan, S. [Centre for Crystal Growth, VIT University, Vellore 632014 (India); Sridhar, R. [Saraswathi Velu Engineering College, Sholinghur, Vellore 632501 (India)

2016-10-31

The present study addresses the effect of fillers on the microstructure and tensile strength of dissimilar joints of Inconel 625 and UNS S32205 by pulsed current gas tungsten arc welding (PCGTAW) employing ERNiCrMo-10 and ERNiCrMo-14 fillers. This study attested that tensile failure occurred in the fusion zone of the dissimilar joints for both the cases in the as-welded un-peened condition. Double shot laser shock peening (DLSP) was performed on the fusion zone of these PCGTA welds on the cap and root regions of the weldments. It was assimilated that after DLSP on the cap and root regions of the weldments, the yield and tensile strength of the welded joints employing these fillers were improved considerably. Residual stress analysis were carried out on the dissimilar coupons using X-ray Diffraction analysis. The results demonstrated that after subjecting to double sided DLSP, the fusion zones were subjected to compressive residual stresses. The present study articulated that shot peening using low energy laser beam resulted in better tensile strength.

Fracture mechanics analysis of the steam generator tube after shot peening

International Nuclear Information System (INIS)

Shin, Kyu In; Jhung, Myung Jo; Choi, Young Hwan; Park, Jai Hak

2003-01-01

One of the main degradation of steam generator tubes is stress corrosion cracking induced by residual stress. The resulting damages can cause tube bursting or leakage of the primary water which contained radioactivity. Primary water stress corrosion crack occurs at the location of tube/tubesheet hard rolled transition zone. In order to investigate the effect of shot peening on stress corrosion cracking, stress intensity factors are calculated for the crack which is located in the induced residual stress field

Analysis of shot-peening and residual stress relaxation in the nickel-based superalloy RR1000

International Nuclear Information System (INIS)

Foss, B.J.; Gray, S.; Hardy, M.C.; Stekovic, S.; McPhail, D.S.; Shollock, B.A.

2013-01-01

This work assesses the residual stress relaxation of the nickel-based alloy RR1000 due to thermal exposure and dwell-fatigue loading. A number of different characterization methods, including X-ray residual stress analysis, electron back-scattered diffraction, microhardness testing and focused ion beam secondary electron imaging, contributed to a detailed study of the shot-peened region. Thermal exposure at 700 °C resulted in a large reduction in the residual stresses and work-hardening effects in the alloy, but the subsurface remained in a beneficial compressive state. Oxidizing environments caused recrystallization in the near surface, but did not affect the residual stress-relaxation behaviour. Dwell-fatigue loading caused the residual stresses to return to approximately zero at nearly all depths. This work forms part of an ongoing investigation to determine the effects of shot-peening in this alloy with the motivation to improve the fatigue and oxidation resistance at 700 °C

Parametric study on single shot peening by dimensional analysis method incorporated with finite element method

Science.gov (United States)

Wu, Xian-Qian; Wang, Xi; Wei, Yan-Peng; Song, Hong-Wei; Huang, Chen-Guang

2012-06-01

Shot peening is a widely used surface treatment method by generating compressive residual stress near the surface of metallic materials to increase fatigue life and resistance to corrosion fatigue, cracking, etc. Compressive residual stress and dent profile are important factors to evaluate the effectiveness of shot peening process. In this paper, the influence of dimensionless parameters on maximum compressive residual stress and maximum depth of the dent were investigated. Firstly, dimensionless relations of processing parameters that affect the maximum compressive residual stress and the maximum depth of the dent were deduced by dimensional analysis method. Secondly, the influence of each dimensionless parameter on dimensionless variables was investigated by the finite element method. Furthermore, related empirical formulas were given for each dimensionless parameter based on the simulation results. Finally, comparison was made and good agreement was found between the simulation results and the empirical formula, which shows that a useful approach is provided in this paper for analyzing the influence of each individual parameter.

An investigation of the residual stress characterization and relaxation in peened friction stir welded aluminum-lithium alloy joints

International Nuclear Information System (INIS)

Hatamleh, Omar; Rivero, Iris V.; Swain, Shayla E.

2009-01-01

In this investigation the residual stresses generated from friction stir welded (FSW) 2195 aluminum-lithium alloy joints were characterized. The results derived from this research revealed significant levels of tensile residual stresses at the surface and throughout the thickness of the FSW samples. Furthermore, residual stress relaxation at the surface and throughout the thickness of the samples was assessed for laser peened friction stir welded aluminum-lithium joints. To do so the samples were cycled several times at a constant amplitude load. The results indicated that most of the relaxation for the surface residual stresses took place during the first cycle of loading. Also, residual stresses relaxation throughout the thickness of the welded region of unpeened samples significantly exceeded the relaxation exhibited by the laser peened samples.

Investigation on femto-second laser irradiation assisted shock peening of medium carbon (0.4% C) steel

Energy Technology Data Exchange (ETDEWEB)

Majumdar, Jyotsna Dutta, E-mail: jyotsna@metal.iitkgp.ernet.in [Dept. of Metal. & Maters. Eng., I. I. T., Kharagpur, WB 721302 (India); Gurevich, Evgeny L., E-mail: gurevich@lat.rub.de [Ruhr-Universität Bochum, Ls. Laseranwendungstechnik, Universitätsstr. 150, 44801 Bochum (Germany); Kumari, Renu, E-mail: renumetalbit@gmail.com [Dept. of Metal. & Maters. Eng., I. I. T., Kharagpur, WB 721302 (India); Ostendorf, Andreas, E-mail: andreas.ostendorf@ruhr-uni-bochum.de [Ruhr-Universität Bochum, Ls. Laseranwendungstechnik, Universitätsstr. 150, 44801 Bochum (Germany)

2016-02-28

Graphical abstract: - Highlights: • Peening effect of 0.4% C steel by femtosecond laser irradiation. • Microstructural investigation of the irradiated surface. • Residual stress decreased from 152 MPa to 140 MPa to −330 MPa by laser processing. • Decreased wear depth to a maximum of four times as compared to as-received substrate. • Mechanism of wear for both as-received and laser processed surface were established. - Abstract: In the present study, the effect of femtosecond laser irradiation on the peening behavior of 0.4% C steel has been evaluated. Laser irradiation has been conducted with a 100 μJ and 300 fs laser with multiple pulses under varied energy. Followed by laser irradiation, a detailed characterization of the processed zone was undertaken by scanning electron microscopy, and X-ray diffraction technique. Finally, the residual stress distribution, microhardness and wear resistance properties of the processed zone were also evaluated. Laser processing leads to shock peening associated with plasma formation and its expansion, formation of martensite and ferrito–pearlitic phase in the microstructure. Due to laser processing, there is introduction of residual stress on the surface which varies from high tensile (140 MPa) to compressive (−335 MPa) as compared to 152 MPa of the substrate. There is a significant increase in microhardness to 350–500 VHN as compared to 250 VHN of substrate. The fretting wear behavior against hardened steel ball shows a significant reduction in wear depth due to laser processing. Finally, a conclusion of the mechanism of wear has been established.

El Tratado de Lisboa (Un juego de espejos rotos

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Juan Manuel de Faramiñán Gilbert

2009-01-01

Full Text Available El fracaso del Tratado por el que se establece una Constitución para Europa produjo un periodo de incertidumbre y perplejidad del que ha costado mucho sobreponerse. Por un momento, todo parecía resquebrajarse y se tuvo la sensación de que la imagen de unidad en la diversidad, que con tanta dificultad se había forjado, se partía hecha añicoscomo un espejo roto. No obstante, como en un “juego de espejos rotos”, el ideal europeísta se ha ido recomponiendo con un gran esfuerzo, dando lugar a un texto, el Tratado de Lisboa, que encierra una solución de compromiso con el fin de saldar la crisis cuando el futuro de la Unión Europea parecía oscurecerse. Como en los poemas de Alejandra Pizarnik, “cuando el palacio de la noche encierra su hermosura, pulsaremos los espejos hasta que nuestros rostros canten como ídolos” y, así fue como con un esfuerzo milimetrado se ha ido recomponiendo este rompecabezas de cristales con el fin de que en él se refleje, otra vez, la ansiada imagen global. Como se señala enPreámbulo del Tratado de Lisboa, deberemos estar resueltos a salvar una nueva etapa en proceso de integración europea y habrá que recordar “la importancia histórica de que la división del continente europeo haya tocado a su fin y la necesidad de sentar unas bases firmes para la construcción de la futura Europa”.

Entre el collage y el bricolaje. Una cierta mirada hacia El desprecio de Godard en Los abrazos rotos de Almodóvar

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Agustín Gómez Gómez

2012-10-01

Full Text Available En Los abrazos rotos, Almodóvar construye un relato a partir de otros relatos. Lo hará de dos formas. Por una parte muestra -lo que denominamos collage- un conjunto de obras pictóricas y cinematográficas principalmente. Por otra construye unas relaciones más ocultas, menos visibles, que englobamos dentro de la definición de bricolage de Levi-Strauss. Esta última forma nos conduce a El desprecio (Le mépris, 1963 de Godard, que es la que utiliza para narrar la relación entre Martel y Lena.

Use of shot-peening to improve stress corrosion resistance of steam generator tubes of PWR nuclear power plants

International Nuclear Information System (INIS)

Michaut, B.; Slama, G.

1985-11-01

A shot-peening process has been developed for treating the internal side of thin tubes (1 to 1.3 mm) of which diameter is between 19 and 22 mm, used in steam generators of nuclear power plants; this process can be applied to irradiated media. Shot-peening effect has been characterised by stress profiles in depth (internal skin; measurement by X rays) and by induced stress profiles (external skin; stress gauge). The efficiency of the process (100%) has been established by corrosion testing on mockups, either in boiling MgCl 2 , or in caustic medium (10%) at 350 0 C under 180 bars of internal pressure. The process has been used with success on more than 20000 tubes and will be applied later at a larger scale in France and in foreign countries [fr

Modelling of the deformation of shot peened cylindrical specimens of 42 CrMo4 in uniaxial tension and deformation and of the resulting macro residual stresses

International Nuclear Information System (INIS)

Schulze, V.; Voehringer, O.; Macherauch, E.

1998-01-01

Tensile and compressive stress-strain-curves of shot peened and unpeened specimens of quenched and tempered 42 CrMo 4 (AISI 4140) with a diameter of 5 mm only differ in the yield strengths and in the Lueders-deformation. In comparison to the core the regions close to the surface of shot peened cylindrical specimens bear relatively large axial and tangential residual stresses and show different deformation properties. A multi-layer-model was developed to describe both the tensile as well as the compressive deformation behaviour of shot peened cylindrical specimens quantitatively. The calculated transitions from the elastic to the elastic-plastic deformation state during tensile and compressive loading agree quite well with the experimental observations. Also the changes of axial and tangential macro residual stresses after distinct tensile or compressive deformations are in best agreement with the measurements. (orig.)

Fatigue performance improvement in AISI 4140 steel by dynamic strain aging and dynamic precipitation during warm laser shock peening

Energy Technology Data Exchange (ETDEWEB)

Ye Chang [School of Industrial Engineering, Purdue University, West Lafayette, IN 47906 (United States); Suslov, Sergey; Kim, Bong Joong; Stach, Eric A. [School of Materials Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, IN (United States); Cheng, Gary J., E-mail: gjcheng@purdue.edu [School of Industrial Engineering, Purdue University, West Lafayette, IN 47906 (United States)

2011-02-15

Warm laser shock peening (WLSP) is a thermomechanical treatment technique combining the advantages of laser shock peening and dynamic strain aging (DSA). Through DSA, WLSP of steel increases the dislocation density and stabilizes the dislocation structure by pinning of mobile dislocations by carbon atoms. In addition, WLSP generates nanoscale carbide precipitates through strain-induced precipitation. The carbide precipitates stabilize the microstructure by dislocation pinning. This results in higher stability of the dislocation structure and thus improves the stability of the compressive residual stress. In this study the mechanism of fatigue performance improvement in AISI 4140 steel by WLSP is investigated. It is found that microstructures formed after WLSP lead to a higher stability of dislocation structures and residual stress, which are beneficial for fatigue performance.

Fatigue performance improvement in AISI 4140 steel by dynamic strain aging and dynamic precipitation during warm laser shock peening

International Nuclear Information System (INIS)

Ye Chang; Suslov, Sergey; Kim, Bong Joong; Stach, Eric A.; Cheng, Gary J.

2011-01-01

Warm laser shock peening (WLSP) is a thermomechanical treatment technique combining the advantages of laser shock peening and dynamic strain aging (DSA). Through DSA, WLSP of steel increases the dislocation density and stabilizes the dislocation structure by pinning of mobile dislocations by carbon atoms. In addition, WLSP generates nanoscale carbide precipitates through strain-induced precipitation. The carbide precipitates stabilize the microstructure by dislocation pinning. This results in higher stability of the dislocation structure and thus improves the stability of the compressive residual stress. In this study the mechanism of fatigue performance improvement in AISI 4140 steel by WLSP is investigated. It is found that microstructures formed after WLSP lead to a higher stability of dislocation structures and residual stress, which are beneficial for fatigue performance.

Evaluation of shot peening on the fatigue strength of anodized Ti-6Al-4V alloy

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Costa Midori Yoshikawa Pitanga

2006-01-01

Full Text Available The increasingly design requirements for modern engineering applications resulted in the development of new materials with improved mechanical properties. Low density, combined with excellent weight/strength ratio as well as corrosion resistance, make the titanium attractive for application in landing gears. Fatigue control is a fundamental parameter to be considered in the development of mechanical components. The aim of this research is to analyze the fatigue behavior of anodized Ti-6Al-4V alloy and the influence of shot peening pre treatment on the experimental data. Axial fatigue tests (R = 0.1 were performed, and a significant reduction in the fatigue strength of anodized Ti-6Al-4V was observed. The shot peening superficial treatment, which objective is to create a compressive residual stress field in the surface layers, showed efficiency to increase the fatigue life of anodized material. Experimental data were represented by S-N curves. Scanning electron microscopy technique (SEM was used to observe crack origin sites.

Laser Shock Peening on Microwave Sintered Aluminum Alloy Nanocompo-Sites

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S. Prabhakaran

2018-04-01

Full Text Available The current work focusses on low energy laser shock peening (LSP on graphene (0.4 wt % – AA 2900 nano-composite fabricated through powder metallurgy (PM technique. The added graphene serves the pinning effect and blocks the grain growth in the composite. Further, LSP has been carried out on the developed composites. As a consequence, LSP contributed the additional grain refinement effectively to the nanocomposites leading to large texture strengthening. Improvement in the hardness and tensile strength achieved with the addition of graphene and further improvement due to LSP process is achieved for the prepared nanocomposites.

A New Multi-Gaussian Auto-Correlation Function for the Modeling of Realistic Shot Peened Random Rough Surfaces

International Nuclear Information System (INIS)

Hassan, W.; Blodgett, M.

2006-01-01

Shot peening is the primary surface treatment used to create a uniform, consistent, and reliable sub-surface compressive residual stress layer in aero engine components. A by-product of the shot peening process is random surface roughness that can affect the measurements of the resulting residual stresses and therefore impede their NDE assessment. High frequency eddy current conductivity measurements have the potential to assess these residual stresses in Ni-base super alloys. However, the effect of random surface roughness is expected to become significant in the desired measurement frequency range of 10 to 100 MHz. In this paper, a new Multi-Gaussian (MG) auto-correlation function is proposed for modeling the resulting pseudo-random rough profiles. Its use in the calculation of the Apparent Eddy Current Conductivity (AECC) loss due to surface roughness is demonstrated. The numerical results presented need to be validated with experimental measurements

A STUDY ON THE PROPERTIES OF SURFACE – ACTIVE FLUIDS USED IN BURNISHING AND SHOT PEENING PROCESSES

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Kazmierz Zaleski

2016-09-01

Full Text Available A method is presented for the study of surface-active properties of a fluids, in burnishing and shot peening processes used, which consists in comparing mean plastic strains of thin metal foil subjected to tensile tests in the examined fluid and in air. As a surface-active additive to the fluid (mineral oil, methyl polymethacrylate solution was used. It was found that the surfactant activity coefficient depended on the type of examined fluid as well as on the thickness of the foil being stretched. Results of analyses of the surface-active properties of a fluid can be compared only when metal foils of equal thickness made from one specific material are used. It can be supposed that the introduction of methyl polymethacrylate solution as an additive to the metalworking fluid will have a beneficial effect on the course and the results of burnishing and shot peening of metals.

Evaluation of Fatigue Strength Improvement by CFRP Laminates and Shot Peening onto the Tension Flanges Joining Corrugated SteelWebs

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Zhi-Yu Wang

2015-08-01

Full Text Available Corrugated steel web with inherent high out-of-plane stiffness has a promising application in configuring large span highway bridge girders. Due to the irregularity of the configuration details, the local stress concentration poses a major fatigue problem for the welded flange plates of high strength low alloy structural steels. In this work, the methods of applying CFRP laminate and shot peening onto the surfaces of the tension flanges were employed with the purpose of improving the fatigue strength of such configuration details. The effectiveness of this method in the improvement of fatigue strength has been examined experimentally. Test results show that the shot peening significantly increases hardness and roughness in contrast to these without treatment. Also, it has beneficial effects on the fatigue strength enhancement when compared against the test data of the joints with CFRP strengthening. The stiffness degradation during the loading progress is compared with each treatment. Incorporating the stress acting on the constituent parts of the CFRP laminates, a discussion is made regarding the mechanism of the retrofit and related influencing factors such as corrosion and economic cost. This work could enhance the understanding of the CFRP and shot peening in repairing such welded details and shed light on the reinforcement design of welded joints between corrugated steel webs and flange plates.

Self-seeded single-frequency laser peening method

Science.gov (United States)

DAne, C Brent; Hackey, Lloyd A; Harris, Fritz B

2012-06-26

A method of operating a laser to obtain an output pulse having a single wavelength, comprises inducing an intracavity loss into a laser resonator having an amount that prevents oscillation during a time that energy from the pump source is being stored in the gain medium. Gain is built up in the gain medium with energy from the pump source until formation of a single-frequency relaxation oscillation pulse in the resonator. Upon detection of the onset of the relaxation oscillation pulse, the intracavity loss is reduced, such as by Q-switching, so that the built-up gain stored in the gain medium is output from the resonator in the form of an output pulse at a single frequency. An electronically controllable output coupler is controlled to affect output pulse characteristics. The laser acts a master oscillator in a master oscillator power amplifier configuration. The laser is used for laser peening.

Identification marking by means of laser peening

Science.gov (United States)

Hackel, Lloyd A.; Dane, C. Brent; Harris, Fritz

2002-01-01

The invention is a method and apparatus for marking components by inducing a shock wave on the surface that results in an indented (strained) layer and a residual compressive stress in the surface layer. One embodiment of the laser peenmarking system rapidly imprints, with single laser pulses, a complete identification code or three-dimensional pattern and leaves the surface in a state of deep residual compressive stress. A state of compressive stress in parts made of metal or other materials is highly desirable to make them resistant to fatigue failure and stress corrosion cracking. This process employs a laser peening system and beam spatial modulation hardware or imaging technology that can be setup to impress full three dimensional patterns into metal surfaces at the pulse rate of the laser, a rate that is at least an order of magnitude faster than competing marking technologies.

Potential of using water jet peening as a surface treatment process for welded\

Czech Academy of Sciences Publication Activity Database

Srivastava, M.; Tripathi, R.; Hloch, Sergej; Chattopadhyaya, S.; Dixit, A. R.

2016-01-01

Roč. 149, č. 149 (2016), s. 472-480 E-ISSN 1877-7058. [International Conference on Manufacturing Engineering and Materials, ICMEM 2016. Nový Smokovec, 06.06.2016-10.06.2016] R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : water jet * peening * residual stress Subject RIV: JQ - Machines ; Tools http://www.sciencedirect.com/science/article/pii/S1877705816312097

The influence of nanostructured features on bacterial adhesion and bone cell functions on severely shot peened 316L stainless steel.

Science.gov (United States)

Bagherifard, Sara; Hickey, Daniel J; de Luca, Alba C; Malheiro, Vera N; Markaki, Athina E; Guagliano, Mario; Webster, Thomas J

2015-12-01

Substrate grain structure and topography play major roles in mediating cell and bacteria activities. Severe plastic deformation techniques, known as efficient metal-forming and grain refining processes, provide the treated material with novel mechanical properties and can be adopted to modify nanoscale surface characteristics, possibly affecting interactions with the biological environment. This in vitro study evaluates the capability of severe shot peening, based on severe plastic deformation, to modulate the interactions of nanocrystallized metallic biomaterials with cells and bacteria. The treated 316L stainless steel surfaces were first investigated in terms of surface topography, grain size, hardness, wettability and residual stresses. The effects of the induced surface modifications were then separately studied in terms of cell morphology, adhesion and proliferation of primary human osteoblasts (bone forming cells) as well as the adhesion of multiple bacteria strains, specifically Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and ampicillin-resistant Escherichia coli. The results indicated a significant enhancement in surface work hardening and compressive residual stresses, maintenance of osteoblast adhesion and proliferation as well as a remarkable decrease in the adhesion and growth of gram-positive bacteria (S. aureus and S. epidermidis) compared to non-treated and conventionally shot peened samples. Impressively, the decrease in bacteria adhesion and growth was achieved without the use of antibiotics, for which bacteria can develop a resistance towards anyway. By slightly grinding the surface of severe shot peened samples to remove differences in nanoscale surface roughness, the effects of varying substrate grain size were separated from those of varying surface roughness. The expression of vinculin focal adhesions from osteoblasts was found to be singularly and inversely related to grain size, whereas the attachment of gram

Application of laser peening with a composite-type optical fiberscope for pancreatic calculus fracture

International Nuclear Information System (INIS)

Takei, Norio; Ishikawa, Noriko; Ito, Fuyumi; Nishimura, Akihiko; Oka, Kiyoshi

2010-01-01

For low infestation treatment on pancreatolithiasis, we propose that laser peening phenomena by use of a composite-type optical fiberscope are useful to crush pancreatic a calculus into fragments, Nanosecond laser pulses go through the composite-type optical fiberscope and are focused on the surface of the pancreatic calculus. Laser processed fracture shapes on the calculus were observed and the pulse energy dependence were measured. The essential points for system integration were discussed. (author)

Analysis of the Impact of Double Shot Peening on the Value of Roughness Parameter and Distribution of Stresses in the RSA 501 Alloy (Al Mg5 Mn1 Sc0.8 Zr0.4

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Paulina Byczkowska

2017-09-01

Full Text Available The bead blasting process is widespread in both the automotive and aerospace industry and is performed in order to improve the fatigue strength of various components. Bead blasting is a cold plastic forming process during which the surface of the material processed is hit by small, hard particles consisting of steel pellets, bearing balls or glass beads. It increases the hardness of the outer layer and establishes compression stresses inside it, which is why this processing is often used to improve fatigue strength. Contrary to other peening methods, bead blasting does not result in a reduction in the height of the processed surface’s unevenness in most cases. Shot peening changes the residual tensile stresses into residual compression stresses, thanks to which, the lifetime of the parts processed is extended and their carrying capacity is increased. The double shot peening process proposed by the authors consists in a two-stage bead blasting process. The first stage consists in blasting with round cast steel pellets, pellets cut from wire or cast iron pellets. During the second stage the same samples underwent glass bead blasting. The tests conducted on the RSA-501 aluminum alloy indicate that as a result of the processing medium’s impact in the form of glass beads or pellets of different diameter and shape, a permanent plastic deformation of the material surface occurs. On the basis of the obtained results it is possible to infer that the choice of parameters of both conventional shot peening and the double shot peening determine the impact thereof on the material’s mechanical properties. Thanks to the application of the double shot peening process there is a noticeable decrease in value of the Ra parameter, by about 40% on average. When analyzing the compressive stress results it is possible to state that after the first blasting process the value of stress was increasing when moving deeply into the sample from its surface, while after

Structural Technology Evaluation Analysis Program (STEAP). Delivery Order 0025: Laser Peening for Reliable Fatigue Life

Science.gov (United States)

2010-12-01

uncertainty in the material properties of steel associated with martensitic transformations on the residual stress field induced by the welding process. They...FEM calculation of residual stresses induced by laser shock processing in stainless steels ,” Modelling and Simulation in Materials Science and...the surface a small indentation or dimple. A schematic of the process is shown in figure 5. Figure 5: Schematic of the Shot Peening Process Steel balls

EFFECTS OF LASER SHOCK PEENING ON SCC BEHAVIOR OF ALLOY 600

Energy Technology Data Exchange (ETDEWEB)

Abhishek Telang; Amrinder Gill; S.R.Mannava; Vijay K. Vasudevan; Dong Qian; Sebastien P. Teysseyre

2013-08-01

In this study, the effects of laser shock peening (LSP) on stress corrosion cracking (SCC) behavior of Alloy 600 in tetrathionate solution were investigated. The degree of sensitization was quantified using double loop electrochemical potentiokinetic reactivation (DLEPR) tests. The sensitized Alloy 600 was demonstrated to be susceptible to intergranular SCC in tetrathionate solution. Following LSP, residual stresses and the amount of plastic strain introduced in Alloy 600 were characterized. The effects of LSP on SCC susceptibility of Alloy 600 in tetrathionate solution were evaluated by slow strain rate tests and constant load tests. Results indicate a significant increase in resistance to crack initiation and decreased susceptibility to SCC after LSP.

Numerical analysis of residual stress of Al-Mg-Mn-Sc-Zr alloy subjected to surface strengthening by shot peening

Directory of Open Access Journals (Sweden)

Mariusz Stegliński

2015-03-01

Full Text Available In this paper, we presented the results of the analysis of the stresses in the Al-Mg5%-Mn1,5%-Sc0,8%-Zr0,4% alloy after shot peening process using solver ANSYSANSYSANSYS LS-Dyna. The computational model illustrates the phenomena occurring as a result of plastic deformation caused by hitting a steel ball on the surface of the analyzed aluminium alloy. We analyzed two input variables: diameter and speed of a ball. The resulting normal stress distribution centred exposes the minimum compressive stress at a position located at a depth point of Belayev 0.125 mm with a value of σ = –345 MPa. Variable parameter shows the correlation of the boundary conditions of minimum stress increase with increasing ball’s diameter and its speed. Selected points of numerical analysis were verified with experimental results.[b]Keywords[/b]: materials science, numerical analysis, metal forming, shot peening, aluminium

Effects of laser shock peening with contacting foil on micro laser texturing surface of Ti6Al4V

Science.gov (United States)

Dai, Fengze; Zhang, Zidong; Ren, Xudong; Lu, Jinzhong; Huang, Shu

2018-02-01

Ti6Al4V samples with micro-dimple arrays were subjected to laser shock peening in contact with foil (HCLSP). The surface roughness, micro-hardness, the residual stress distribution and the surface morphology of the micro-dimple arrays were studied to evaluate the effects of HCLSP. Moreover, the surface topography of the foils in contact was also analyzed. The gap existence between the foil and the to-be treated surface led the mechanism of HCLSP to be different compared to regular laser shock peening. The surface roughness reduction, the work-hardening effects, the compressive residual stress and the micro crack enclosure were achieved. A simplified ball-hitting-surface model was utilized to analyze the HCLSP impact. The model could well explain the experimental results. When treated by the HCLSP with H62 foil at the laser power density of 4.24 GW/cm2, the Ti6Al4V samples with micro-dimple arrays exhibit well surface topography and mechanical performance.

Effects of combined plasma chromizing and shot peening on the fatigue properties of a Ti6Al4V alloy

Science.gov (United States)

Yu, Shouming; Liu, Daoxin; Zhang, Xiaohua; Du, Dongxing

2015-10-01

A plasma chromizing treatment was conducted on Ti6Al4V samples by employing the recently developed double glow plasma surface alloying technology. The Cr-alloyed layer consisted of four sub-layers, namely the Cr deposition, Cr2Ti, CrTi4, and Cr-Ti solid-solution layers. The local hardness and moduli were determined via nanoindentation. In addition, the fatigue properties of the samples were evaluated by using a rotating-bending fatigue machine under a given load. The results showed that the hardness or elastic moduli of the adjacent sub-layers differed significantly and the fatigue properties of the Ti6Al4V alloy deteriorated with the plasma chromizing treatment. This deterioration stemmed mainly from cracks initiated at the interfaces between the sub-layers and the microstructural changes of the substrate; these changes were induced by the high temperature used in the plasma chromizing process. However, the fatigue life of the plasma-chromized samples was increased by a shot peening post-treatment. The fatigue life of the samples resulting from this combination of treatments was slightly higher than that of the single-shot-peened Ti6Al4V substrate. In fact, the sample retaining only the Cr-Ti solid-solution layer (that is, the first three sub-layers were removed), when shot-peened, exhibited the highest fatigue life among all the tested samples; this was attributed to that sample having the highest residual compressive stress, the significant work hardening, and the good hardness to toughness balance.

Laser shock peening of titanium 6-4 alloy

International Nuclear Information System (INIS)

Brar, N.S.; Hopkins, A.; Laber, M.W.

2000-01-01

Laser shock peening of titanium 6-4 has been shown to improve its high cycle fatigue life. Residual compressive stresses generated on the surface of titanium 6-4, as a result of laser shocking, have shown dramatic improvement in the performance of aircraft turbine blades. Laser shocking of titanium was carried out with a 20 ns pulse width, 50 joule pulsed laser, operated by LSP Technologies, Columbus, OH. Titanium disks, 20-mm in diameter, and ranging in thicknesses from zero (bare LiF) to 3-mm were subjected to laser shock to monitor amplitude and temporal stress profiles of the pulsed laser. Laser shock stress amplitudes on the back of titanium disks were monitored with VISAR using LiF as the window material. The peak shock stress produced in LiF (titanium thickness zero) was measured to be 16±1 GPa. The laser shock amplitude decays to about 2.7 GPa while propagating through 3-mm thick disk of titanium 6-4

Effect of Applied Stress and Temperature on Residual Stresses Induced by Peening Surface Treatments in Alloy 600

Science.gov (United States)

Telang, A.; Gnäupel-Herold, T.; Gill, A.; Vasudevan, V. K.

2018-04-01

In this study, the effects of applied tensile stress and temperature on laser shock peening (LSP) and cavitation shotless peening (CSP)-induced compressive residual stresses were investigated using neutron and x-ray diffraction. Residual stresses on the surface, measured in situ, were lower than the applied stress in LSP- and CSP-treated Alloy 600 samples (2 mm thick). The residual stress averaged over the volume was similar to the applied stress. Compressive residual stresses on the surface and balancing tensile stresses in the interior relax differently due to hardening induced by LSP. Ex situ residual stress measurements, using XRD, show that residual stresses relaxed as the applied stress exceeded the yield strength of the LSP- and CSP-treated Alloy 600. Compressive residual stresses induced by CSP and LSP decreased by 15-25% in magnitude, respectively, on exposure to 250-450 °C for more than 500 h with 10-11% of relaxation occurring in the first few hours. Further, 80% of the compressive residual stresses induced by LSP and CSP treatments in Alloy 600 were retained even after long-term aging at 350 °C for 2400 h.

The flashcal process for the fabrication of fuel-metal oxides using the whiteshell roto-spray calciner

International Nuclear Information System (INIS)

Sridhar, T.S.

1988-01-01

A one-step, continuous, thermochemical calcination process, called the FLASHCAL (Flash Calcination) process has been developed for the production of single- and mixed-oxide powders of fuel metals (uranium, thorium and plutonium) from the respective nitrate solutions using the Whiteshell Roto-Spray Calciner (RSC). The metal-nitrate feed solution, either by itself or mixed with a suitable chemical reactant or additive, is converted to its oxide powder in the RSC at temperatures between 300 and 600 0 C. Rapid denitration takes place in the calciner, yielding the metal-oxide powders while simultaneously destroying any excess chemical additive and reaction by-products. In the production of precursor oxide powders suitable for fuel fabrication, the FLASHCAL process has advantages over batch calcination and other processes that involve precipitation and filtration steps because fewer processing and handling operations are needed. Results obtained with thorium nitrate and uranium nitrate-thorium nitrate mixtures indicate that some measure of control over the size distribution and morphology of the oxide product powders is possible in this process with the proper selection of chemical additive, as well as the operating parameters of the calciner

On the effectiveness of surface severe plastic deformation by shot peening at cryogenic temperature

Science.gov (United States)

Novelli, M.; Fundenberger, J.-J.; Bocher, P.; Grosdidier, T.

2016-12-01

The effect of cryogenic temperature (CT) on the graded microstructures obtained by severe shot peening using surface mechanical attrition treatment (SMAT) was investigated for two austenitic steels that used different mechanisms for assisting plastic deformation. For the metastable 304L steel, the depth of the hardened region increases because CT promotes the formation of strain induced martensite. Comparatively, for the 310S steel that remained austenitic, the size of the subsurface affected region decreases because of the improved strength of the material at CT but the fine twinned nanostructures results in significant top surface hardening.

In-situ observation of dislocation and analysis of residual stresses by FEM/DDM modeling in water cavitation peening of pure titanium

International Nuclear Information System (INIS)

Ju, D Y; Han, B

2015-01-01

In this paper, in order to approach this problem, specimens of pure titanium were treated with WCP, and the subsequent changes in microstructure, residual stress, and surface morphologies were investigated as a function of WCP duration. The influence of water cavitation peening (WCP) treatment on the microstructure of pure titanium was investigated. A novel combined finite element and dislocation density method (FEM/DDM), proposed for predicting macro and micro residual stresses induced on the material subsurface treated with water cavitation peening, is also presented. A bilinear elastic-plastic finite element method was conducted to predict macro-residual stresses and a dislocation density method was conducted to predict micro-residual stresses. These approaches made possible the prediction of the magnitude and depth of residual stress fields in pure titanium. The effect of applied impact pressures on the residual stresses was also presented. The results of the FEM/DDM modeling were in good agreement with those of the experimental measurements. (paper)

Investigation of the Use of Laser Shock Peening for Enhancing Fatigue and Stress Corrosion Cracking Resistance of Nuclear Energy Materials

Energy Technology Data Exchange (ETDEWEB)

Vasudevan, Vijay K. [Univ. of Cincinnati, OH (United States); Jackson, John [Idaho National Lab. (INL), Idaho Falls, ID (United States); Teysseyre, Sebastien [Idaho National Lab. (INL), Idaho Falls, ID (United States); Alexandreanu, Bogdan [Argonne National Lab. (ANL), Argonne, IL (United States); Chen, Yiren [Argonne National Lab. (ANL), Argonne, IL (United States)

2017-03-07

The objective of this project, which includes close collaboration with scientists from INL and ANL, is to investigate and demonstrate the use of advanced mechanical surface treatments like laser shock peening (LSP) and ultrasonic nanocrystal surface modification (UNSM) and establish baseline parameters for enhancing the fatigue properties and SCC resistance of nuclear materials like nickel-based alloy 600 and 304 stainless steel. The research program includes the following key elements/tasks: 1) Procurement of Alloy 600 and 304 SS, heat treatment studies; 2) LSP and UNSM processing of base metal and welds/HAZ of alloys 600 and 304; (3) measurement and mapping of surface and sub-surface residual strains/stresses and microstructural changes as a function of process parameters using novel methods; (4) determination of thermal relaxation of residual stresses (macro and micro) and microstructure evolution with time at high temperatures typical of service conditions and modeling of the kinetics of relaxation; (5) evaluation of the effects of residual stress, near surface microstructure and temperature on SCC and fatigue resistance and associated microstructural mechanisms; and (6) studies of the effects of bulk and surface grain boundary engineering on improvements in the SCC resistance and associated microstructural and cracking mechanisms

PTC-6 vacuum system: WallWalker{trademark} and Blastrac{reg_sign} shot blast cleaning system

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-02-01

The LTC Americas, Inc. wall decontamination technology consisted of two pneumatic hand-held tools: (1) a roto-peen scaler that used star cutters and (2) a 3-piston hammer with reciprocating bits. The hand-held tools were used in conjunction with the LTC PTC-6 vacuum system which captured dust and debris as the wall decontamination took place. Recommendations for improved worker safety and health during use of the PTC-6 vacuum system with hand-held tools include: (1) keeping all hoses and lines as orderly as possible in compliance with good housekeeping requirements; (2) ergonomic training to include techniques in lifting, bending, stooping, twisting, etc.; (3) use of a clamping system to hold hoses to the vacuum system; (4) a safety line on the air line connections; (5) use of a mechanical lifting system for waste drum removal; and (6) the use of ergonomically designed tools.

PTC-6 vacuum system: WallWaler trademark Blastrac reg-sign shot blast cleaning system

International Nuclear Information System (INIS)

1998-02-01

The LTC Americas, Inc. wall decontamination technology consisted of two pneumatic hand-held tools: (1) a roto-peen scaler that used star cutters and (2) a 3-piston hammer with reciprocating bits. The hand-held tools were used in conjunction with the LTC PTC-6 vacuum system which captured dust and debris as the wall decontamination took place. Recommendations for improved worker safety and health during use of the PTC-6 vacuum system with hand-held tools include: (1) keeping all hoses and lines as orderly as possible in compliance with good housekeeping requirements; (2) ergonomic training to include techniques in lifting, bending, stooping, twisting, etc.; (3) use of a clamping system to hold hoses to the vacuum system; (4) a safety line on the air line connections; (5) use of a mechanical lifting system for waste drum removal; and (6) the use of ergonomically designed tools

Residual stress and microstructural behaviour of a shot peened steel in fatigue. An X-ray diffraction study

Energy Technology Data Exchange (ETDEWEB)

Bergstroem, J.

1986-01-01

The surface residual stress behaviour during fatigue of the quenched and tempered medium strength low-alloyed steel SS 2244-05, equivalent to AISI 4140, has been investigated. Notched specimens of shot peened and ground surface conditions were used. The residual stresses were measured by the X-ray diffraction sin/sup 2/psi-method at intervals in the fatigue tests. Fatigue testing was performed with constant load amplitude at nominal pull-push and pull-pull cycling. The effects of peak-load and variable amplitude were also examined. It was found that the residual stress relaxation could be linked to a total mean stress relaxation towards zero, to an extent which is ruled by a softening criteria. Fatigue test data of the shot peened and ground surface conditions are also given. An X-ray diffraction line broadening analysis was undertaken to examine the microstructural behaviour due to fatigue loading and its correlation to the residual stress behaviour. Single-peak analysis with a Voigt-function method was used to estimate the microstructural parameters, domain size and microstrain. Multiple-peak analysis according to the Warren-Averbach method was used to verify the single-peak analysis. The dislocation density was found to decrease depending on the load amplitude, while the dislocation arrangement follows a pattern depending on yield history.

High temperature mechanical properties and surface fatigue behavior improving of steel alloy via laser shock peening

International Nuclear Information System (INIS)

Ren, N.F.; Yang, H.M.; Yuan, S.Q.; Wang, Y.; Tang, S.X.; Zheng, L.M.; Ren, X.D.; Dai, F.Z.

2014-01-01

Highlights: • The properties of 00C r 12 were improved by laser shock processing. • A deep layer of residual compressive stresses was introduced. • Fatigue life was enhanced about 58% at elevated temperature up to 600 °C. • The pinning effect is the reason of prolonging fatigue life at high temperature. - Abstract: Laser shock peening was carried out to reveal the effects on ASTM: 410L 00C r 12 microstructures and fatigue resistance in the temperature range 25–600 °C. The new conception of pinning effect was proposed to explain the improvements at the high temperature. Residual stress was measured by X-ray diffraction with sin 2 ψ method, a high temperature extensometer was utilized to measure the strain and control the strain signal. The grain and precipitated phase evolutionary process were observed by scanning electron microscopy. These results show that a deep layer of compressive residual stress is developed by laser shock peening, and ultimately the isothermal stress-controlled fatigue behavior is enhanced significantly. The formation of high density dislocation structure and the pinning effect at the high temperature, which induces a stronger surface, lower residual stress relaxation and more stable dislocation arrangement. The results have profound guiding significance for fatigue strengthening mechanism of components at the elevated temperature

Aplicación del shot peening en implantes dentales de titanio para la mejora de la osteointegración

Directory of Open Access Journals (Sweden)

Aparicio, C.

1998-05-01

Full Text Available In order to optimize the implant-bone fixation, different shot peening treatments with different shot particles (TiO₂, Al₂O₃ y SiC. La rugosidad, SiC have been made. The influence that each type of shot particle has in the bone colonization on the different treatment surfaces has been determined by means of osteoblast-like cells culture. Commercially pure titanium discs have been shot peened. Their qualitative and quantitative surface roughness have been characterized; as well as their surface contamination caused by the shot particles. Particle size has also been determined, before and after the treatment, in order to evaluate their breaking averages. Finally, a TiO₂ shot particles manufacture process by sintering has been developed. The manufacture has been necessary since this type of shot particles are not available in the market with the adequate size.

Con el propósito de optimizar la fijación entre el implante y el hueso, se han realizado tratamientos de shot peening con distintos tipos de partículas de proyección: TiO₂, Al₂O₃ y SiC. La rugosidad superficial obtenida será colonizada por hueso neoformado que producirá un anclaje implante-hueso. Para valorar la influencia que cada tipo de material abrasivo tiene en la colonización del hueso sobre las superficies tratadas, se han realizado ensayos in vitro de cultivos osteoblásticos. El shot peening se ha llevado a cabo en discos de titanio comercialmente puro, sobre los que se ha caracterizado cuantitativa y cualitativamente la rugosidad después del tratamiento; así como la contaminación de la superficie por las partículas. También se ha determinado el tamaño de las partículas, antes y después del tratamiento, para valorar sus porcentajes de rotura. Finalmente, se ha propuesto un proceso de fabricación de partículas de TiO₂ por sinterización en el laboratorio

Residual stresses evolution in hardening, cold drawn or shot-peening carbon steel as a function of the heating temperature

International Nuclear Information System (INIS)

Vannes, A.-B.; Parisot, Alain; Fougeres, Roger; Theolier, Maurice

1977-01-01

Residual stress variations are studied in hardening, cold-drawn, shot-peening carbon steel samples as a function of heating temperature or the tempering one. For temperatures between 100 0 C and 250 0 C, a relative maximum is observed for the mean level of the residual stresses. These results are explained on the basis of two antagonistic mechanisms: restoration and ageing [fr

Numerical Study of Mechanical Response of Pure Titanium during Shot Peening

Science.gov (United States)

Wang, Y. M.; Cheng, J. P.; Yang, H. P.; Zhang, C. H.

2018-05-01

Mechanical response of pure titanium impacted by a steel ball was simulated using finite element method to investigate stress and strain evolution during shot peening. It is indicated that biaxial residual stress was obtained in the surface layer while in the interior triaxial residual stress existed because the S33 was comparable to S11 and S22. With decreasing the depth from the top surface, the stress was higher during impacting, but the stress relief extent became more significant when the ball rebounded. Therefore the maximum residual stress was formed in the subsurface layer with depth of 130 μm. As for the residual strain, it is shown that the maximum residual strain LE33 was obtained at the depth of 60 μm corresponding to the maximum shear stress during impacting.

High energy x-ray synchrotron radiation analysis of residual stress distribution of shot-peened steels

International Nuclear Information System (INIS)

Tanaka, Keisuke; Akiniwa, Yoshiaki; Kimachi, Hirohisa; Suzuki, Kenji; Yanase, Etsuya; Nishio, Kouji; Kusumi, Yukihiro

2001-01-01

A high energy X-ray beam from synchrotron radiation source SPring-8 was used to determine the residual stress distribution beneath the shot-peened surface of carbon steel plates. By using the monochromatic X-ray beam with an energy of 72 keV, the relation between 2θ and sin 2 ψ was obtained by the side-inclination method upto sin 2 ψ = 0.9. The distribution of the residual stress was determined from the non-linearity of the relation between 2θ and sin 2 ψ. (author)

Conduta anestésica em cesariana em gestante com aneurisma intracraniano não roto Conducta anestésica en cesárea en embarazada con aneurisma cerebral íntegro Anesthetic conduct in cesarean section in a parturient with unruptured intracranial aneurysm

Directory of Open Access Journals (Sweden)

Luciana de Souza Cota Carvalho

2009-12-01

Full Text Available JUSTIFICATIVA E OBJETIVOS: O manuseio anestésico para cesariana programada em gestante com aneurisma intracraniano não roto é particularmente interessante, pois apresenta diversas particularidades relacionadas às alterações fisiológicas da gestação acrescida dos riscos de ruptura do aneurisma durante o procedimento anestésico. A literatura é escassa nesse assunto, sendo assim importante a divulgação dos casos. RELATO DO CASO: Gestante de termo, 31 anos, com aneurisma intracraniano não roto submetida à cesariana programada sob anestesia peridural simples. O procedimento evoluiu sem intercorrências para mãe e filho. CONCLUSÕES: Recomendações baseadas em evidências para anestesia obstétrica em pacientes portadoras de aneurisma intracraniano não roto não existem. Não há dados experimentais ou clínicos que confirmem ou refutem anestesia geral ou regional nesse contexto. Dessa forma, a decisão de qual técnica utilizar deve ser feita com bases individuais, ponderando os riscos e benefícios de cada procedimento e a experiência do profissional que irá conduzi-la.JUSTIFICATIVA Y OBJETIVOS: El manejo anestésico para la cesárea programada en embarazada con aneurisma cerebral íntegro es particularmente interesante, porque presenta diversas particularidades relacionadas con las alteraciones fisiológicas del embarazo y por añadidura, con los riesgos de ruptura del aneurisma durante el procedimiento anestésico. La literatura es parca en ese asunto, siendo muy importante la divulgación de los casos. RELATO DEL CASO: Embarazada de término, 31 años, con aneurisma cerebral no roto y sometida a la cesárea programada bajo anestesia epidural simple. El procedimiento evolucionó sin intercurrencias para la madre y el hijo. CONCLUSIONES: No existen recomendaciones basadas en evidencias, para la anestesia obstétrica en pacientes portadoras de aneurisma cerebral no roto. No hay datos experimentales o clínicos que confirmen o que

Community participation in the Gulf of Uraba: The Case of Bocas del Atrato township and the village of El Roto, municipality of Turbo, Antioquia

International Nuclear Information System (INIS)

Taborda M, Alexander; Maldonado L, Carolina; Palacio, Jaime

2008-01-01

The text sets out from the study of socio cultural aspects and particularly addressing on community participation, the results of a pilot aquaculture project to breed snook (C. undecimalis ) and tarpon (Megalops atlanticus) in The Corregimiento Bocas del Atrato and The Vereda El Roto, Municipality of Turbo, Antioquia. Interdisciplinary work that seeks to generate scientific knowledge tools to assist in mitigating the decline of fish resource in which is based the livelihood of these people, through Participatory Action Research methods. We analyze some socioeconomic and cultural aspects of these communities that influenced the development of the project, along with reflections on the experiences, by way of recommendations for future work such as a call to self critical review of what is the practice interdisciplinary projects of intervention within the framework of sustainable development. The research was conducted between January 2007 and June 2008.

A STUDY ON THE PROPERTIES OF SURFACE – ACTIVE FLUIDS USED IN BURNISHING AND SHOT PEENING PROCESSES

OpenAIRE

Kazmierz Zaleski

2016-01-01

A method is presented for the study of surface-active properties of a fluids, in burnishing and shot peening processes used, which consists in comparing mean plastic strains of thin metal foil subjected to tensile tests in the examined fluid and in air. As a surface-active additive to the fluid (mineral oil), methyl polymethacrylate solution was used. It was found that the surfactant activity coefficient depended on the type of examined fluid as well as on the thickness of the foil being stre...

Shot peening as a pre-treatment to anodic oxidation coating process of AW 6082 aluminum for fatigue life improvement

Czech Academy of Sciences Publication Activity Database

Hadzima, B.; Nový, F.; Trško, L.; Pastorek, F.; Jambor, M.; Fintová, Stanislava

2017-01-01

Roč. 93, 9-12 (2017), s. 3315-3323 ISSN 0268-3768 R&D Projects: GA MŠk(CZ) LQ1601 Institutional support: RVO:68081723 Keywords : Fatigue life * AW 6082 aluminum alloy * Anodizing * Shot peening * Ultrasonic fatigue testing Subject RIV: JL - Materials Fatigue, Friction Mechanics OBOR OECD: Audio engineering, reliability analysis Impact factor: 2.209, year: 2016 https://link.springer.com/content/pdf/10.1007%2Fs00170-017-0776-1.pdf

X-ray Diffraction Investigation of Annealing Behavior of Peened Surface Deformation Layer on Precipitation Hardening Stainless Steel

Science.gov (United States)

Huang, Junjie; Wang, Zhou; Gan, Jin; Yang, Ying; Huang, Feng; Wu, Gang; Meng, Qingshuai

2018-05-01

In order to investigate the recrystallization behavior of peened surface deformation layer of precipitation hardening stainless steel, a classic x-ray diffraction line profile analysis, Voigt method, was carried out on peened 17-4PH with different isothermal annealing temperatures. The activation energy of domain boundary migration ( Q a) and the activation energy of microstrain relaxation ( Q b) were calculated by regression analysis in different annealing temperature conditions. The results show that the value of Q a decreases with annealing temperature increasing, which is due to the influence of precipitation (ɛ-Cu) size on the movements of grain and subgrain boundaries. The maximum growth rate of ɛ-Cu particles occurs during 400 to 500 °C interval. Compared with growth behavior of domain size, microstrain relaxation behavior is less sensitive to precipitation particle size. The effects of annealing temperature and time on dislocation density are both significant when annealing temperature is lower than 500 °C. However, the effect of annealing temperature on dislocation density becomes insignificant when annealing temperature is higher than 500 °C. 300 °C annealing temperature only leads to the microstrain relaxation but nearly cannot lead to the domain size growth even if prolonging annealing time. Microstructure enhancement effect still exists in plastic deformation layer when 300 °C annealing temperature lasts for 60 min but nearly disappears when 600 °C annealing temperature lasts for 20 min.

X-ray Diffraction Investigation of Annealing Behavior of Peened Surface Deformation Layer on Precipitation Hardening Stainless Steel

Science.gov (United States)

Huang, Junjie; Wang, Zhou; Gan, Jin; Yang, Ying; Huang, Feng; Wu, Gang; Meng, Qingshuai

2018-04-01

In order to investigate the recrystallization behavior of peened surface deformation layer of precipitation hardening stainless steel, a classic x-ray diffraction line profile analysis, Voigt method, was carried out on peened 17-4PH with different isothermal annealing temperatures. The activation energy of domain boundary migration (Q a) and the activation energy of microstrain relaxation (Q b) were calculated by regression analysis in different annealing temperature conditions. The results show that the value of Q a decreases with annealing temperature increasing, which is due to the influence of precipitation (ɛ-Cu) size on the movements of grain and subgrain boundaries. The maximum growth rate of ɛ-Cu particles occurs during 400 to 500 °C interval. Compared with growth behavior of domain size, microstrain relaxation behavior is less sensitive to precipitation particle size. The effects of annealing temperature and time on dislocation density are both significant when annealing temperature is lower than 500 °C. However, the effect of annealing temperature on dislocation density becomes insignificant when annealing temperature is higher than 500 °C. 300 °C annealing temperature only leads to the microstrain relaxation but nearly cannot lead to the domain size growth even if prolonging annealing time. Microstructure enhancement effect still exists in plastic deformation layer when 300 °C annealing temperature lasts for 60 min but nearly disappears when 600 °C annealing temperature lasts for 20 min.

AN EFFECT OF SHOT PEENING ON GROWTH AND RETARDATION OF PHYSICALLY SHORT FATIGUE CRACKS IN AN AIRCRAFT Al-ALLOY

OpenAIRE

Ivo Černý

2009-01-01

Results of an investigation of effect of shot peening on development of physically short fatigue crack in an aircraft V-95 Al-alloy, which is of a similar type as 7075 alloy, are described and discussed in the paper. The first part deals with adaptation and verification of direct current potential drop method for detection and measurement of short crack initiation and growth. The specific material and quite large dimensions of flat specimens with side necking of a low stress concentration fac...

Relationship between microhardness and fatigue strength after glass micro-bead peening and ion implantation

International Nuclear Information System (INIS)

Lunarski, J.; Zielecki, M.

1989-01-01

Results of tests on fatigue strength and condition of the surface layer, produced by ion implantation or/and glass micro-bead peening for E1961Sz and 12H2N4MAZ steels and WT3-1 titanium alloy are reported. In the tests the following characteristics are measured: Knoop hardness, residual stresses (by etching method), surface roughness, and oscillatory bending fatigue limit at the resonance frequency of the specimen. The test results indicate that for the examined steels there is a strong correlation between surface microhardness and fatigue limit, in spite of various surface treatments. This fact enables to predict changes in the fatigue limit, basing on the results of surface microhardness measurements, which are inexpensive and easy to perform. (author)

Residual stress stability and alternating bending strength of AISI 4140 after shot peening and successive annealing

Energy Technology Data Exchange (ETDEWEB)

Menig, R.; Schulze, V.; Voehringer, O. [Inst. fuer Werkstoffkunde I, Univ. of Karlsruhe (TH), Karlsruhe (Germany)

2002-07-01

Increases of residual stress stability and alternating bending strength of shot peened AISI 4140 are obtained by successive annealing treatments. This is caused by static strain aging effects, which lead to pinning of dislocations by carbon atoms and finest carbides. It will be shown that by short-time annealing of a quenched and tempered AISI 4140 it is possible to maximize the positive effect of static strain aging, while minimizing the detrimental effect of thermal residual stress relaxation, which was measured by X-ray diffraction method. Static strain aging effects were also found to be responsible for an increase of the quasi static and cyclic surface yield strengths. (orig.)

On the Eigenstrain Application of Shot-Peened Residual Stresses Within a Crystal Plasticity Framework: Application to Ni-Base Superalloy Specimens (Postprint)

Science.gov (United States)

2016-01-06

alloys : a review,. Int J Fatigue 2002;24(10):1021–36. [4] Peyre P, Fabbro R, Merrien P, Lieurade HP. Laser shock processing of aluminium alloys ...Benedetti M, Fontanari V, Santus C, Bandini M. Notch fatigue behaviour of shot peened high-strength aluminium alloys : experiments and predictions...crack growth behaviour of aluminium alloy 2024-T351. Int J Fatigue 2009;31 (6):1081–8. [66] Korsunsky AM, Regino GM, Nowell D. Variational eigenstrain

Modelling of the deformation of shot peened cylindrical specimens of 42 CrMo4 in uniaxial tension and deformation and of the resulting macro residual stresses; Modellierung der einachsigen Zug- und Druck-Verformung kugelgestrahlter Zylinderproben aus verguetetem 42 CrMo4 und der dabei auftretenden Makroeigenspannungsaenderungen

Energy Technology Data Exchange (ETDEWEB)

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

1998-10-01

Tensile and compressive stress-strain-curves of shot peened and unpeened specimens of quenched and tempered 42 CrMo 4 (AISI 4140) with a diameter of 5 mm only differ in the yield strengths and in the Lueders-deformation. In comparison to the core the regions close to the surface of shot peened cylindrical specimens bear relatively large axial and tangential residual stresses and show different deformation properties. A multi-layer-model was developed to describe both the tensile as well as the compressive deformation behaviour of shot peened cylindrical specimens quantitatively. The calculated transitions from the elastic to the elastic-plastic deformation state during tensile and compressive loading agree quite well with the experimental observations. Also the changes of axial and tangential macro residual stresses after distinct tensile or compressive deformations are in best agreement with the measurements. (orig.) 29 refs.

Evaluation of shot peened surfaces using characterization technique of three-dimensional surface topography

International Nuclear Information System (INIS)

Kurokawa, S; Ariura, Y

2005-01-01

Objective parameters to characterize global topography of three-dimensional surfaces have been derived. The idea of this evaluation is to separate the topography into two global form deviations and residual ones according to the degree of curved surfaces. A shot peened Almen strip is measured by profilometer and concrete parameters of inclination and circular-arc shaped global topography are extracted using the characterization technique. The arc height is calculated using the circular arc-shaped part and compared with a value measured by an Almen gauge. The relation between the coverage and roughness parameters is also investigated. The advantage of this evaluation is that it is possible to determine the arc height and the coverage at the same time from single measured topography. In addition, human error can be excluded from measurement results. This method has the wide application in the field of measurement

On the effect of deep-rolling and laser-peening on the stress-controlled low- and high-cycle fatigue behavior of Ti-6Al-4V at elevated temperatures up to 550?C

Energy Technology Data Exchange (ETDEWEB)

Ritchie, IAltenberger, RKNalla, YSano LWagner, RO

2012-04-01

The effect of surface treatment on the stress/life fatigue behavior of a titanium Ti-6Al-4V turbine fan blade alloy is investigated in the regime of 102 to 106 cycles to failure under fully reversed stress-controlled isothermal push-pull loading between 25? and 550?C at a frequency of 5 Hz. Specifically, the fatigue behavior was examined in specimens in the deep-rolled and laser-shock peened surface conditions, and compared to results on samples in the untreated (machined and stress annealed) condition. Although the fatigue resistance of the Ti-6Al-4V alloy declined with increasing test temperature regardless of surface condition, deep-rolling and laser-shock peening surface treatments were found to extend the fatigue lives by factors of more than 30 and 5-10, respectively, in the high-cycle and low-cycle fatigue regimes at temperatures as high as 550?C. At these temperatures, compressive residual stresses are essentially relaxed; however, it is the presence of near-surface work hardened layers, with a nanocystalline structure in the case of deep-rolling and dense dislocation tangles in the case of laser-shock peening, which remain fairly stable even after cycling at 450?-550?C, that provide the basis for the beneficial role of mechanical surface treatments on the fatigue strength of Ti-6Al-4V at elevated temperatures.

Material model validation for laser shock peening process simulation

International Nuclear Information System (INIS)

Amarchinta, H K; Grandhi, R V; Langer, K; Stargel, D S

2009-01-01

Advanced mechanical surface enhancement techniques have been used successfully to increase the fatigue life of metallic components. These techniques impart deep compressive residual stresses into the component to counter potentially damage-inducing tensile stresses generated under service loading. Laser shock peening (LSP) is an advanced mechanical surface enhancement technique used predominantly in the aircraft industry. To reduce costs and make the technique available on a large-scale basis for industrial applications, simulation of the LSP process is required. Accurate simulation of the LSP process is a challenging task, because the process has many parameters such as laser spot size, pressure profile and material model that must be precisely determined. This work focuses on investigating the appropriate material model that could be used in simulation and design. In the LSP process material is subjected to strain rates of 10 6  s −1 , which is very high compared with conventional strain rates. The importance of an accurate material model increases because the material behaves significantly different at such high strain rates. This work investigates the effect of multiple nonlinear material models for representing the elastic–plastic behavior of materials. Elastic perfectly plastic, Johnson–Cook and Zerilli–Armstrong models are used, and the performance of each model is compared with available experimental results

Surface topography of cylindrical gear wheels after smoothing in abrasive mass, honing and shot peening

International Nuclear Information System (INIS)

Michalski, J; Pawlus, P; Zelasko, W

2011-01-01

The present paper presents the analysis of surface topography of gear teeth as the result of final machining processes. Teeth of multiple cylindrical gears shaped by grinding were smoothed in abrasive mass, honed or shot peened. The measurement of gears were made using coordinate measuring machine and 3D surface topography stylus instrument. The following deviations were studied; pitch deviation, total pitches deviations, variation of teeth thickness and deviation of gear radial run-out. Changes in teeth surface topography during machining process were determined. 3D surface topography parameters, surface directionality as well as areal autocorrelation and power spectral density functions were taken into consideration. As the results of the analysis, the best surface topography with regard to gear operational properties was recommended.

A parametric study of laser spot size and coverage on the laser shock peening induced residual stress in thin aluminium samples

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M. Sticchi

2015-07-01

Full Text Available Laser Shock Peening is a fatigue enhancement treatment using laser energy to induce compressive Residual Stresses (RS in the outer layers of metallic components. This work describes the variations of introduced RS-field with peen size and coverage for thin metal samples treated with under-water-LSP. The specimens under investigation were of aluminium alloy AA2024-T351, AA2139-T3, AA7050-T76 and AA7075-T6, with thickness 1.9 mm. The RS were measured by using Hole Drilling with Electronic Speckle Pattern Interferometry and X-ray Diffraction. Of particular interest are the effects of the above mentioned parameters on the zero-depth value, which gives indication of the amount of RS through the thickness, and on the value of the surface compressive stresses, which indicates the magnitude of induced stresses. A 2D-axisymmetrical Finite Element model was created for a preliminary estimation of the stress field trend. From experimental results, correlated with numerical and analytical analysis, the following conclusions can be drawn: increasing the spot size the zero-depth value increases with no significant change of the maximum compressive stress; the increase of coverage leads to significant increase of the compressive stress; thin samples of Al-alloy with low Hugoniot Elastic Limit (HEL reveal deeper compression field than alloy with higher HEL value.

The Effect Of Two-Stage Age Hardening Treatment Combined With Shot Peening On Stress Distribution In The Surface Layer Of 7075 Aluminum Alloy

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Kaczmarek Ł.

2015-09-01

Full Text Available The article present the results of the study on the improvement of mechanical properties of the surface layer of 7075 aluminum alloy via two-stage aging combined with shot peening. The experiments proved that thermo-mechanical treatment may significantly improve hardness and stress distribution in the surface layer. Compressive stresses of 226 MPa±5.5 MPa and hardness of 210±2 HV were obtained for selected samples.

Effects of laser shock peening on stress corrosion behavior of 7075 aluminum alloy laser welded joints

Energy Technology Data Exchange (ETDEWEB)

Wang, J.T., E-mail: jiasqq1225@126.com [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); School of Materials Engineering, Jiangsu University of Technology, Changzhou 213001 (China); Zhang, Y.K. [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); School of Mechanical Engineering, Southeast University, Nanjing 211189 (China); Chen, J.F.; Zhou, J.Y.; Ge, M.Z.; Lu, Y.L.; Li, X.L. [School of Materials Engineering, Jiangsu University of Technology, Changzhou 213001 (China)

2015-10-28

7075 aluminum alloy weldments were processed by an intensive process known as laser shock peening (LSP), meanwhile its stress corrosion behaviors were observed by scanning electron microscopy (SEM) and slow strain rate tensile (SSRT) tests. Results showed that the effect of LSP on corrosion behavior of the joint was fairly useful and obvious. With LSP, the elongation, time of fracture and static toughness after the SSRT test were improved by 11.13%, 20% and 100%, respectively. At the same time, the location of the fracture also changed. LSP led to a transition of the fracture type from transgranular to intergranular The reasons for these enhancements of the joint on corrosion behavior were caused by microstructure, residual stress, micro-hardness, and fracture appearance.

On the influence of mechanical surface treatments--deep rolling and laser shock peening--on the fatigue behavior of Ti-6Al-4V at ambient and elevated temperatures

International Nuclear Information System (INIS)

Nalla, R.K.; Altenberger, I.; Noster, U.; Liu, G.Y.; Scholtes, B.; Ritchie, R.O.

2003-01-01

It is well known that mechanical surface treatments, such as deep rolling, shot peening and laser shock peening, can significantly improve the fatigue behavior of highly-stressed metallic components. Deep rolling (DR) is particularly attractive since it is possible to generate, near the surface, deep compressive residual stresses and work hardened layers while retaining a relatively smooth surface finish. In the present investigation, the effect of DR on the low-cycle fatigue (LCF) and high-cycle fatigue (HCF) behavior of a Ti-6Al-4V alloy is examined, with particular emphasis on the thermal and mechanical stability of the residual stress states and the near-surface microstructures. Preliminary results on laser shock peened Ti-6Al-4V are also presented for comparison. Particular emphasis is devoted to the question of whether such surface treatments are effective for improving the fatigue properties at elevated temperatures up to ∼450 deg. C, i.e. at a homologous temperature of ∼0.4T/T m (where T m is the melting temperature). Based on cyclic deformation and stress/life (S/N) fatigue behavior, together with the X-ray diffraction and in situ transmission electron microscopy (TEM) observations of the microstructure, it was found that deep rolling can be quite effective in retarding the initiation and initial propagation of fatigue cracks in Ti-6Al-4V at such higher temperatures, despite the almost complete relaxation of the near-surface residual stresses. In the absence of such stresses, it is shown that the near-surface microstructures, which in Ti-6Al-4V consist of a layer of work hardened nanoscale grains, play a critical role in the enhancement of fatigue life by mechanical surface treatment

Residual stresses caused by head-on and 45° foreign object damage for a laser shock peened Ti–6Al–4V alloy aerofoil

International Nuclear Information System (INIS)

Zabeen, S.; Preuss, M.; Withers, P.J.

2013-01-01

This paper investigates the effect on the residual stresses of foreign object damage (FOD) to a previously laser shock peened (LSP) leading edge (LE). FOD was introduced onto the LE of the aerofoil-shaped specimen through ballistic impacts of a cube edge at angles of 0° and 45° to the leading edge. The residual stress distribution was mapped around the FOD notch by synchrotron X-ray diffraction. The results suggest that for both impact angles, the FOD event superimposed a significant additional residual stress on top of the pre-existing stress associated with the LSP process. In particular, the compressive stress was found to be largest directly beneath the notch and the tensile region, seen previously for unpeened aerofoils beneath the compressive zone, was absent due to the pre-existing peening stress field. This may help to explain the improved fatigue strength observed previously. It is shown that the FOD notch created by 45° impact was asymmetric in shape and smaller in depth compared to that created at 0°. The residual stresses were somewhat larger for the 0° impact condition than for 45° partly due to the larger notch depth introduced in the former case.

Enhancing the moderator effectiveness as a heat sink during loss-of-coolant accidents in CANDU-PHW reactors using glass-peened surfaces

International Nuclear Information System (INIS)

Nitheanandan, T.; Tiede, R.W.; Sanderson, D.B.; Fong, R.W.L.; Coleman, C.E.

1998-08-01

The horizontal fuel channel concept is a distinguishing feature of the CANDU-PHW reactor. Each fuel channel consists of a Zr-2.5Nb pressure tube and a Zircaloy-2 calandria tube, separated by a gas filled annulus. The calandria tube is surrounded by heavy-water moderator that also provides a backup heat sink for the reactor core. This heat sink (about 10 mm away from the hot pressure tube) ensures adequate cooling of fuel in the unlikely event of a loss-of-coolant accident (LOCA). One of the ways of enhancing the use of the moderator as a heat sink is to improve the heat-transfer characteristics between the calandria tube and the moderator. This enhancement can be achieved through surface modifications to the calandria tube which have been shown to increase the tube's critical heat flux (CHF) value. An increase in CHIF could be used to reduce moderator subcooling requirements for CANDU fuel channels or increase the margin to dryout. A series of experiments was conducted to assess the benefits provided by glass-peening the outside surface of calandria tubes for postulated LOCA conditions. In particular, the ability to increase the tube's CHF, and thereby reduce moderator subcooling requirements was assessed. Results from the experiments confirm that glass-peening the outer surface of a tube increases its CHF value in pool boiling. This increase in CHF could be used to reduce moderator subcooling requirements for CANDU fuel channels by at least 5 degrees C. (author)

Residual Stress Distribution and Microstructure of a Multiple Laser-Peened Near-Alpha Titanium Alloy

Science.gov (United States)

Umapathi, A.; Swaroop, S.

2018-04-01

Laser peening without coating (LPwC) was performed on a Ti-2.5 Cu alloy with multiple passes (1, 3 and 5), using a Nd:YAG laser (1064 nm) at a constant overlap rate of 70% and power density of 6.7 GW cm-2. Hardness and residual stress profiles indicated thermal softening near the surface (hardness (235 HV at 500 μm) and maximum residual stress (- 890 MPa at 100 μm) were observed for LPwC with 1 pass. Surface roughness and surface 3-D topography imaging showed that the surface roughness increased with the increase in the number of passes. XRD results indicated no significant β phases. However, peak shifts, broadening and asymmetry were observed and interpreted based on dislocation activity. Microstructures indicated no melting or resolidification or refinement of grains at the surface. Twin density was found to increase with the increase in the number of passes.

Ruptured thoracic aortic aneurysm in patient with systemic lupus erythematosus Aneurisma roto da aorta descendente em paciente com lúpus eritematoso sistêmico

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Daniel Oliveira De Conti

2011-03-01

Full Text Available It is reported a ruptured descending thoracic aortic aneurysm in a 25-year-old systemic lupus erythematosus woman who underwent 19 years steroid therapy. She was treated with 2 endovascular stent-grafts, discharged from hospital 13 days after the procedure in good health. Three months later she returned with hemorrhagic shock due to high digestive hemorrhage secondary to an aortic-esophageal fistula. She underwent to an open emergency surgery, and died during the post-operative period.Paciente de 25 anos, do sexo feminino, portadora de lúpus eritematoso sistêmico, fazendo uso de corticoesteroide havia 19 anos, deu entrada em unidade de emergência com aneurisma roto de aorta torácica descendente. Foi submetida a tratamento endovascular com 2 stents, recebeu alta hospitalar no 13º dia de pós-operatório, em boas condições de saúde. Três meses depois, retornou em choque hemorrágico secundário a hemorragia digestiva alta. Feito o diagnóstico de fístula aorto-esofágica, foi submetida à cirurgia aberta de emergência, indo a óbito durante o período pós-operatório.

A study on the reliability evaluation of shot peened aluminium alloy using accelerated life test

International Nuclear Information System (INIS)

Nam, Ji Hun; Cheong, Seong Kyun; Kang, Min Woo

2006-01-01

In this paper, the concept of accelerated life test, which is a popular research field nowadays, is applied to the shot peened material. To predict the efficient and exact room temperature fatigue characteristics from the high temperature fatigue data, the adequate accelerated model is investigated. Ono type rotary bending fatigue tester and high temperature chamber were used for the experiment. Room temperature fatigue lives were predicted by applying accelerated models and doing reliability evaluation. Room temperature fatigue tests were accomplished to check the effectiveness of predicted data and the adequate accelerated life test models were presented by considering errors. Experimental result using Arrhenius model, fatigue limit obtain almost 5.45% of error, inverse power law has about 1.36% of error, so we found that inverse power law is applied well to temperature-life relative of shot peended material

The gradient crystalline structure and microhardness in the treated layer of TC17 via high energy shot peening

International Nuclear Information System (INIS)

Li, Huimin; Liu, Yingang; Li, Miaoquan; Liu, Hongjie

2015-01-01

Graphical abstract: - Highlights: • The gradient nanocrystalline structure was induced in treated layer of TC17. • The thickness of nanograin layer with an average grain size of 10.5 nm was 20 μm. • The composition of the treated layer of TC17 was discussed. • The gradient variation of the microhardness was obtained in treated layer of TC17. - Abstract: The gradient nanocrystalline structure from the topmost surface to the matrix of a bulk coarse-grained TC17 was attained by using high energy shot peening treatment at an air pressure of 0.35 MPa and a processing duration of 30 min. The thickness from the topmost surface with a grain size of about 10.5 nm to the matrix with a micrometer structure was about 120 μm, and the thickness in the nanocrystalline layer was about 20 μm. The microscopic and nanocrystalline structure characteristic in the treated layer were investigated via X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscopy. The nanograins layer, the nanometer-thick laminated structure layer, the refined grains layer and the low-strain matrix layer occurred in sequence from the topmost surface to the matrix, and therefore the gradient nanocrystalline structure in the treated layer was produced by using high energy shot peening. TEM investigation confirmed that the dislocation activity with very high stacking fault energy induced by surface severe plastic deformation mainly controlled the grain refinement. The microhardness (HV 0.02 ) from the topmost surface to the matrix gradually increased by 43% from 440 to 629 and the gradient variation of the microhardness with the depths from the topmost surface to the matrix of treated TC17 was obtained.

Effects of Plasma ZrN Metallurgy and Shot Peening Duplex Treatment on Fretting Wear and Fretting Fatigue Behavior of Ti6Al4V Alloy.

Science.gov (United States)

Tang, Jingang; Liu, Daoxin; Zhang, Xiaohua; Du, Dongxing; Yu, Shouming

2016-03-23

A metallurgical zirconium nitride (ZrN) layer was fabricated using glow metallurgy using nitriding with zirconiuming prior treatment of the Ti6Al4V alloy. The microstructure, composition and microhardness of the corresponding layer were studied. The influence of this treatment on fretting wear (FW) and fretting fatigue (FF) behavior of the Ti6Al4V alloy was studied. The composite layer consisted of an 8-μm-thick ZrN compound layer and a 50-μm-thick nitrogen-rich Zr-Ti solid solution layer. The surface microhardness of the composite layer is 1775 HK 0.1 . A gradient in cross-sectional microhardness distribution exists in the layer. The plasma ZrN metallurgical layer improves the FW resistance of the Ti6Al4V alloy, but reduces the base FF resistance. This occurs because the improvement in surface hardness results in lowering of the toughness and increasing in the notch sensitivity. Compared with shot peening treatment, plasma ZrN metallurgy and shot peening composite treatment improves the FW resistance and enhances the FF resistance of the Ti6Al4V alloy. This is attributed to the introduction of a compressive stress field. The combination of toughness, strength, FW resistance and fatigue resistance enhance the FF resistance for titanium alloy.

Tribological Properties of Aluminum Alloy treated by Fine Particle Peening/DLC Hybrid Surface Modification

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Nanbu H.

2010-06-01

Full Text Available In order to improve the adhesiveness of the DLC coating, Fine Particle Peening (FPP treatment was employed as pre-treatment of the DLC coating process. FPP treatment was performed using SiC shot particles, and then AA6061-T6 aluminum alloy was DLC-coated. A SiC-rich layer was formed around the surface of the aluminum alloy by the FPP treatment because small chips of shot particles were embedded into the substrate surface. Reciprocating sliding tests were conducted to measure the friction coefficients. While the DLC coated specimen without FPP treatment showed a sudden increase in friction coefficient at the early stage of the wear cycles, the FPP/DLC hybrid treated specimen maintained a low friction coefficient value during the test period. Further investigation revealed that the tribological properties of the substrate after the DLC coating were improved with an increase in the amount of Si at the surface.

Effects of warm laser peening at elevated temperature on the low-cycle fatigue behavior of Ti6Al4V alloy

Energy Technology Data Exchange (ETDEWEB)

Zhou, J.Z.; Meng, X.K., E-mail: mengdetiankong10@126.com; Huang, S.; Sheng, J.; Lu, J.Z.; Yang, Z.R.; Su, C.

2015-09-03

This study focused on the effects of warm laser peening (WLP) on the fatigue behavior of Ti6Al4V titanium alloy during low-cycle fatigue (LCF) tests. The Ti6Al4V specimens were treated by laser peening at room temperature (RT-LP) and WLP at elevated temperatures from 100 °C to 400 °C. The residual stress relaxation (RSR) tests and LCF tests were conducted subsequently. In addition, the microstructure analysis of fracture surfaces was performed using scanning electron microscope (SEM). Finally, the fracture mechanism of the untreated, RT-LPed and 300 °C-WLPed samples during LCF was revealed. It is found that although the compressive residual stress (CRS) induced by WLP decreases at elevated temperatures, the depth and stability of CRS increase with the increasing treatment temperature, which help to retard the early fatigue crack initiation. Moreover, for the 300 °C-WLPed specimens, the growth rate of effective cracks is decreased and the lengths of crack growth paths are increased by the induced high angle boundaries (HABs) and nano-precipitates. Therefore, specimens treated by WLP at 300 °C are found to have a significantly extended fatigue life when subjected to low-cycle loads. This extended fatigue life is attributed to the great depth and stability of introduced CRS, as well as the enhanced fracture toughness. It can be concluded that 300 °C is the optimal temperature for WLP of Ti6Al4V titanium alloy from the perspective of LCF improvement.

PARTICIPACIÓN COMUNITARIA EN EL GOLFO DE URABÁ: EL CASO DEL CORREGIMIENTO BOCAS DEL ATRATO Y LA VEREDA EL ROTO, MUNICIPIO DE TURBO, ANTIOQUIA

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TABORDA MARÍN ALEXANDER

2010-05-01

Full Text Available El texto expone, desde el estudio de los aspectos socioculturales y el abordaje particular de la participación comunitaria, los resultados de un proyecto experimental de acuicultura de róbalo (Centropomus undecimalis y sábalo (Megalops atlanticus en el Corregimiento de Bocas del Atrato y la vereda El Roto, del Municipio de Turbo, Antioquia. Trabajo interdisciplinario que busca generar herramientas de conocimiento científico para contribuir en la mitigación de la disminución del recurso íctico en el que se basa el sustento de estas poblaciones mediante una metodología de Investigación Acción Participativa. Se analizan algunos aspectos culturales y socioeconómicos de estas comunidades que influyeron en el desarrollo del proyecto, junto con reflexiones sobre las experiencias vividas, a manera de recomendaciones para futuros trabajos de este tipo y como un llamado a la revisión autocrítica de lo que es la práctica de la interdisciplinariedad en proyectos de intervención en el marco del desarrollo sostenible. La investigación se desarrolló entre enero de 2007 y junio de 2008.

Residual stress improved by water jet peening using cavitation for small-diameter pipe inner surfaces

International Nuclear Information System (INIS)

Yasuo, Nakamura; Toshizo, Ohya; Koji, Okimura

2001-01-01

As one of degradation conditions on components used in water, the overlapping effect of environment, material and stress might cause stress corrosion cracking (SCC). Especially, for the tensile residual stress produced by welding, it is particularly effective to reduce the tensile residual stress on the material surface to prevent SCC. In this paper, the residual stress improvement method using cavitation impact generated by a water jet, called Water Jet Peening (WJP), has been developed as the maintenance technology for the inner surfaces of small-diameter Ni-Cr-Fe alloy (Alloy 600) pipes. As the results, by WJP for the inner surface of Alloy 600 pipe (inner diameter; approximately 10-15 mm), we confirmed that the compressive stress generated within the range from the surface to the inner part about 0.5 mm deep and took a maximum value about 350 MPa on the surface. (author)

Steam generator inspection activities at the EPRI NDE Center

International Nuclear Information System (INIS)

Krzywosz, K.

1988-01-01

Various types of corrosion and mechanical damage continue to affect the availability of both recirculating and once-through steam generators. Both the tube bundle and its supporting structure are affected. Intergranular attack and stress corrosion cracking (SCC) are the corrosion-assisted tube-wall damage mechanisms of most concern at this time. Fatigue cracking and fretting at antivibration bars are currently the mechanical damage forms causing most concern. Improved NDE equipment and techniques are providing better detection and characterization of adverse conditions within the steam generators and doing it at an earlier stage. This allows timely corrective action. To maintain the projected life expectancy of existing and new steam generators, remedial measures have been implemented. These measures include shot- or roto-peening, U-bend stress relief, chemical cleaning of secondary side, and sleeving of tubes. The improved NDE technology will also be instrumental in monitoring and assessing the effectiveness of the remedial measures. The revision of guidance documents for steam generator in-service inspection (ISI) is providing more relevant information to support this complex operation. A multitasked project is described that includes evaluation of steam generator tube NDE technology, transfer of this technology to utilities, and rapid response utility assistance

Evaluación del impacto de las técnicas de control del daño en el tratamiento de los pacientes con aneurisma roto de la aorta abdominal. Hospital Universitario San Vicente de Paúl, Medellín, Colombia, enero de 2000 a octubre de 2007

OpenAIRE

John Fernando García V.; Iván Ramiro Arismendi O.; René Fernando Timarán R.; Carolina Bravo C.; José Andrés Uribe M.; Giovanni García M.

2008-01-01

La mortalidad quirúrgica atribuible al aneurisma de la aorta abdominal (AAA) roto oscila entre 40 y 70% según los diversos informes de la literatura; la principal causa de ello es la falla orgánica múltiple (FOM), la que a su vez corresponde, en un porcentaje importante de casos, al complejo de hipertensión abdominal/síndrome del compartimento abdominal (HTA/SCA). A principios de la década de los años 90 aparecieron algunos artículos informando que los pacientes tratados con laparostomía, con...

High Strain Rate Response of 7055 Aluminum Alloy Subject to Square-spot Laser Shock Peening

Science.gov (United States)

Sun, Rujian; Zhu, Ying; Li, Liuhe; Guo, Wei; Peng, Peng

2017-12-01

The influences of laser pulse energy and impact time on high strain rate response of 7055 aluminum alloy subject to square-spot laser shock peening (SLSP) were investigate. Microstructural evolution was characterized by OM, SEM and TEM. Microhardness distribution and in-depth residual stress in 15 J with one and two impacts and 25 J with one and two impacts were analyzed. Results show that the original rolling structures were significantly refined due to laser shock induced recrystallization. High density of microdefects was generated, such as dislocation tangles, dislocation wall and stacking faults. Subgrains and nanograins were induced in the surface layer, resulting in grain refinement in the near surface layer after SLSP. Compressive residual stresses with maximum value of more than -200 MPa and affected depths of more than 1 mm can be generated after SLSP. Impact time has more effectiveness than laser pulse energy in increasing the magnitude of residual stress and achieving thicker hardening layer.

Aneurisma luético de arco aórtico roto, complicado pela oclusão de vasos braquiocefálicos e acidente vascular encefálico isquêmico: relato de caso tratado cirurgicamente

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CORSO Ricardo Barros

2002-01-01

Full Text Available Homem de 44 anos, com dor torácica crônica há um ano, apresentou dois episódios de acidentes vasculares encefálicos isquêmicos, desencadeados pela oclusão e trombose das artérias carótida e subclávia esquerdas, em aneurisma sifilítico gigante de arco aórtico roto. O paciente foi submetido à correção cirúrgica com sucesso via esternotomia mediana, utilizando-se proteção cerebral anterógrada e perfusão corporal distal contínuas. Aspectos referentes à técnica operatória utilizada e ampla revisão bibliográfica das diferentes formas de apresentação do comprometimento cardiovascular na sífilis terciária são discutidos.

Microstructures and Mechanical Properties of Commercially Pure Ti Processed by Rotationally Accelerated Shot Peening

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Zhaowen Huang

2018-03-01

Full Text Available Gradient structured materials possess good combinations of strength and ductility, rendering the materials attractive in industrial applications. In this research, a surface nanocrystallization (SNC technique, rotationally accelerated shot peening (RASP, was employed to produce a gradient nanostructured pure Ti with a deformation layer that had a thickness of 2000 μm, which is thicker than those processed by conventional SNC techniques. It is possible to fabricate a gradient structured Ti workpiece without delamination. Moreover, based on the microstructural features, the microstructure of the processed sample can be classified into three regions, from the center to the surface of the RASP-processed sample: (1 a twinning-dominated core region; (2 a “twin intersection”-dominated twin transition region; and (3 the nanostructured region, featuring nanograins. A microhardness gradient was detected from the RASP-processed Ti. The surface hardness was more than twice that of the annealed Ti sample. The RASP-processed Ti sample exhibited a good combination of yield strength and uniform elongation, which may be attributed to the high density of deformation twins and a strong back stress effect.

Effects of fretting fatigue on the residual stress of shot peened Ti-6Al-4V samples

International Nuclear Information System (INIS)

Martinez, S.A.; Sathish, S.; Blodgett, M.P.; Mall, S.; Namjoshi, S.

2005-01-01

X-ray diffraction residual stress measurement has been utilized as nondestructive tool for the characterization of fretting fatigue damage in shot peened samples of Ti-6Al-4V. Prior to fretting fatigue damage, compressive residual stresses were found to be uniform over the entire face of the sample and independent of the measurement direction. After fretting fatigue, inside and in the vicinity of the fretting damage zone large relaxation of compressive residual stress was observed. An anisotropic residual stress distribution has been observed in the fretting fatigue damaged region. Residual stress measurements in interrupted fretting fatigue experiments showed that the relaxation of residual stress increases as the number of fretting fatigue cycles increase. The results are discussed in the light of their importance in establishing X-ray diffraction residual stress measurement technique as a nondestructive tool to characterize fretting fatigue damage

Análisis tridimensional del proceso de granallado utilizando un modelo de múltiples impactos. // 3d shot peening process analysis using multiple impacts model.

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M. A. Calle Gonzales

2006-05-01

son comparados con resultados experimentales disponibles en la literatura especializada ypresentados en forma de gráficos y tablas.Palabras claves: Granallado, tensión residual, elementos finitos, modelación.____________________________________________________________________________Abstract.The shot peening is one of the most used superficial treatments for, amongst other applications, providing a considerableincrease of the fatigue life elements of machines and structures submitted to cyclic loads. The control of parameters, suchas, the depth of the plastic zone, residual stresses level, among others, is of vital importance to guarantee the adequateapplication of the treatment. To simulate the shot peening process, using the Finite Elements Method, a three-dimensionalrepresentative cell model of the treated part surface is created and submitted to the multiple impact shots. The modelevaluates the compression residual stresses field in different regions of the cell surface, due to the impact shots, in order tofind the best representation through out the cell. The representative profile evaluation is important, since it is responsiblefor the improvement of the mechanical properties of the component. The results reveal additionally, in an implicit way, theeffect of the shot peening process covering, in the behavior of the residual stress profile, which is also commented in thework. The results are compared with experimental results available in the specialized literature and presented in form ofgraphs and tables.Keyword: Shot peening, residual stress, finite elements, modeling.

Surface Morphology and Bending Deformation of 2024-T3 Thin Sheets with Laser Peen Forming

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Wu Junfeng

2018-01-01

Full Text Available Laser peen forming (LPF is a pure mechanical forming method through accumulated plastic strain, which has been successfully applied in wing components. Experimental investigation has been performed to understand the effect of process parameters such as constraint conditions, sheet thickness and laser energy on surface morphology and bending deformation of 2024-T3 thin sheets of dimensions of 76 mm ×19 mm (length × width. The research results indicated that bulges on the aluminum foil were generated at the bottom surface and not generated at the topmost surface. It was different for transition value of two-way bending deformations of thin sheets after LPF with different constraint conditions. Remain flat thicknesses of thin sheets after LPF were about 1 mm ~ 2 mm for 20 J, 25 J and 30 J. Arc heights and curvatures of 3 mm thickness sheets increased with laser energy and those of 2 mm thickness sheets only made little change. It was found that convex deformation, flat, concave deformation and laser deep drawing for thin sheets with different thicknesses after LPF.

Improvement in surface fatigue life of hardened gears by high-intensity shot peening

Science.gov (United States)

Townsend, Dennis P.

1992-04-01

Two groups of carburized, hardened, and ground spur gears that were manufactured from the same heat vacuum induction melted vacuum arc melted (VIM VAR) AISI 9310 steel were endurance tested for surface fatigue. Both groups were manufactured with a standard ground 16 rms surface finish. One group was subjected to a shot peening (SP) intensity of 7 to 9A, and the second group was subjected to a SP intensity of 15 to 17A. All gears were honed after SP to a surface finish of 16 rms. The gear pitch diameter was 8.89 cm. Test conditions were a maximum Hertz stress of 1.71 GPa, a gear temperature of 350 K, and a speed of 10000 rpm. The lubricant used for the tests was a synthetic paraffinic oil with an additive package. The following results were obtained: The 10 pct. surface fatigue (pitting) life of the high intensity (15 to 17A) SPed gears was 2.15 times that of the medium intensity (7 to 9A) SPed gears, the same as that calculated from measured residual stress at a depth of 127 microns. The measured residual stress for the high intensity SPed gears was 57 pct. higher than that for the medium intensity SPed gears at a depth of 127 microns and 540 pct. higher at a depth of 51 microns.

A direct comparison in the fatigue resistance enhanced by surface severe plastic deformation and shot peening in a C-2000 superalloy

Energy Technology Data Exchange (ETDEWEB)

Shaw, Leon L., E-mail: leon.shaw@uconn.edu [Department of Chemical, Materials and Biomolecular Engineering, University of Connecticut, Storrs, CT (United States); Tian, Jia-Wan [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN (United States); Ortiz, Angel L. [Departamento de Ingenieria Mecanica, Energetica y de los Materiales, Universidad de Extremadura, 06071 Badajoz (Spain); Dai Kun [Quality Engineering and Software Technology, East Hartford, CT 06108 (United States); Villegas, Juan C. [Intel Corporation, Chandler, AZ (United States); Liaw, Peter K. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN (United States); Ren Ruiming [School of Materials Science and Engineering, Dalian Jiaotong University, Dalian (China); Klarstrom, Dwaine L. [Haynes International, Inc., Kokomo, IN (United States)

2010-02-15

In this study, we present the first evidence and modeling efforts showing that surface severe plastic deformation (S{sup 2}PD) can be more effective in producing metallic components with superior fatigue properties than shot peening (SP). With the aid of a wide battery of characterization techniques (i.e., X-ray diffractometry, optical microscopy, scanning electron microscopy, transmission electron microscopy, and 3-dimensional non-contact optical profilometry), micro- and nano-hardness testing, and finite element modeling, we have identified the underlying mechanism for the fatigue improvement. It is shown that the enhancement in the fatigue limit is derived from a nanocrystalline surface layer, a work-hardened surface region, and residual compressive stresses at the surface, all of which are introduced by S{sup 2}PD and more substantial than that introduced by SP.

Characterization of the phase transformation in a nanostructured surface layer of 304 stainless steel induced by high-energy shot peening

International Nuclear Information System (INIS)

Ni Zhichun; Wang Xiaowei; Wang Jingyang; Wu Erdong

2003-01-01

Conversion electron Moessbauer spectroscopy and X-ray diffraction analysis have been used to investigate the relationship between character of phase transformation and treatment time in surface nanocrystallized 304 stainless steel (SS) induced by high-energy shot peening (HESP). The results demonstrate that the amount of martensite phase increases remarkably with increasing HESP treatment time, till a maximum value (91%) is reached for 15 min treatment. Longer treatment duration only results in a slight decrease of the amount of martensite phase. Two types of martensite with different magnetic hyperfine fields are observed in the Moessbauer spectra. A theoretical model based on a random distribution of the non-iron atoms in 304 SS is presented to illustrate the relationship between the magnetic hyperfine field and the number of coordinating non-iron atoms. The calculation agrees well with the experimental results

Dislocation pinning effects induced by nano-precipitates during warm laser shock peening: Dislocation dynamic simulation and experiments

Science.gov (United States)

Liao, Yiliang; Ye, Chang; Gao, Huang; Kim, Bong-Joong; Suslov, Sergey; Stach, Eric A.; Cheng, Gary J.

2011-07-01

Warm laser shock peening (WLSP) is a new high strain rate surface strengthening process that has been demonstrated to significantly improve the fatigue performance of metallic components. This improvement is mainly due to the interaction of dislocations with highly dense nanoscale precipitates, which are generated by dynamic precipitation during the WLSP process. In this paper, the dislocation pinning effects induced by the nanoscale precipitates during WLSP are systematically studied. Aluminum alloy 6061 and AISI 4140 steel are selected as the materials with which to conduct WLSP experiments. Multiscale discrete dislocation dynamics (MDDD) simulation is conducted in order to investigate the interaction of dislocations and precipitates during the shock wave propagation. The evolution of dislocation structures during the shock wave propagation is studied. The dislocation structures after WLSP are characterized via transmission electron microscopy and are compared with the results of the MDDD simulation. The results show that nano-precipitates facilitate the generation of highly dense and uniformly distributed dislocation structures. The dislocation pinning effect is strongly affected by the density, size, and space distribution of nano-precipitates.

Laser Shock Peening on Zr-based Bulk Metallic Glass and Its Effect on Plasticity: Experiment and Modeling

Science.gov (United States)

Cao, Yunfeng; Xie, Xie; Antonaglia, James; Winiarski, Bartlomiej; Wang, Gongyao; Shin, Yung C.; Withers, Philip J.; Dahmen, Karin A.; Liaw, Peter K.

2015-05-01

The Zr-based bulk metallic glasses (BMGs) are a new family of attractive materials with good glass-forming ability and excellent mechanical properties, such as high strength and good wear resistance, which make them candidates for structural and biomedical materials. Although the mechanical behavior of BMGs has been widely investigated, their deformation mechanisms are still poorly understood. In particular, their poor ductility significantly impedes their industrial application. In the present work, we show that the ductility of Zr-based BMGs with nearly zero plasticity is improved by a laser shock peening technique. Moreover, we map the distribution of laser-induced residual stresses via the micro-slot cutting method, and then predict them using a three-dimensional finite-element method coupled with a confined plasma model. Reasonable agreement is achieved between the experimental and modeling results. The analyses of serrated flows reveal plentiful and useful information of the underlying deformation process. Our work provides an easy and effective way to extend the ductility of intrinsically-brittle BMGs, opening up wider applications of these materials.

Intergranular stress study of TC11 titanium alloy after laser shock peening by synchrotron-based high-energy X-ray diffraction

Science.gov (United States)

Su, R.; Li, L.; Wang, Y. D.; Nie, Z. H.; Ren, Y.; Zhou, X.; Wang, J.

2018-05-01

The distribution of residual lattice strain as a function of depth were carefully investigated by synchrotron-based high energy X-ray diffraction (HEXRD) in TC11 titanium alloy after laser shock peening (LSP). The results presented big compressive residual lattice strains at surface and subsurface, then tensile residual lattice strains in deeper region, and finally close to zero lattice strains in further deep interior with no plastic deformation thereafter. These evolutions in residual lattice strains were attributed to the balance of direct load effect from laser shock wave and the derivative restriction force effect from surrounding material. Significant intergranular stress was evidenced in the processed sample. The intergranular stress exhibited the largest value at surface, and rapidly decreased with depth increase. The magnitude of intergranular stress was proportional to the severity of the plastic deformation caused by LSP. Two shocks generated larger intergranular stress than one shock.

40 CFR 74.20 - Data for baseline and alternative baseline.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Data for baseline and alternative baseline. 74.20 Section 74.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... baseline and alternative baseline. (a) Acceptable data. (1) The designated representative of a combustion...

In-situ X-ray residual stress measurement on a peened alloy 600 weld metal at elevated temperature under tensile load

International Nuclear Information System (INIS)

Yunomura, Tomoaki; Maeguchi, Takaharu; Kurimura, Takayuki

2014-01-01

In order to verify stability of residual stress improvement effect of peeing for mitigation of stress corrosion cracking in components of PWR plant, relaxation behavior of residual stress induced by water jet peening (WJP) on surface of alloy 600 weld metal (alloy 132) was investigated by in-situ X-ray residual stress measurement under thermal aging and stress condition considered for actual plant operation. Surface residual stress change was observed at the early stage of thermal aging at 360°C, but no significant further stress relaxation was observed after that. Applied stress below yield stress does not significantly affect stress relaxation behavior of surface residual stress. For the X-ray residual stress measurement, X-ray stress constant at room temperature for alloy 600 was determined experimentally with several surface treatment and existence of applied strain. The X-ray stress constant at elevated temperatures were extrapolated theoretically based on the X-ray stress constant at room temperature for alloy 600. (author)

Embarazo ectópico tubárico roto posterior a esterilización quirúrgica (Ruptured tubal ectopic pregnancy after surgical sterilization

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Ismael Suárez Torres

2014-07-01

Full Text Available Resumen (español La esterilización tubárica quirúrgica es un método comúnmente utilizado de anticoncepción. Aunque el embarazo después de la esterilización es poco común, este puede ocurrir y cuando esto ocurre existe un riesgo substancial de convertirse en un embarazo ectópico. Se presenta el caso un embarazo ectópico posterior a la esterilización quirúrgica tubárica en una paciente de 38 años, V gesta, III paras, I cesárea, con antecedentes de uso de dispositivos intrauterinos por varios años antes de la salpingectomía realizada 12 meses antes durante la cesárea, quien consultó por presentar marcada palidez cutáneo-mucosa, retraso menstrual y dolor abdominal de fuerte intensidad. Durante la laparotomía ambas trompas estaban separadas en dos porciones. La porción terminal de la trompa derecha se observó la presencia de una tumoración compatible con un embarazo ectópico tubárico roto. Abstract (english Surgical tubal sterilization is a commonly used method of contraception. Although pregnancy after sterilization is uncommon, when it occurs, there is a substantial risk that it will be an ectopic pregnancy. We report a case of ruptured tubal ectopic pregnancy following surgical tubal sterilization in a 38 years-old patient, gravida V, para III, cesarean I, with history of intrauterine device use for many years before salpingectomy performed 12 months before during cesarean section, who consulted for presenting menstrual delay and severe abdominal pain. During laparotomy both tubes were separated in two portions. There was observed in terminal portion of right tube the presence of a tumor compatible with ruptured tubal ectopic pregnancy.

Influence of Annealing on the Depth Microstructure of the Shot Peened Duplex Stainless Steel at Elevated Temperature

Science.gov (United States)

Feng, Qiang; She, Jia; Xiang, Yong; Wu, Xianyun; Wang, Chengxi; Jiang, Chuanhai

The depth profiles of residual stresses and lattice parameters in the surface layers of shot peened duplex stainless steel at elevated temperature were investigated utilizing X-ray diffraction analysis. At each deformation depth, residual stress distributions in both ferrite and austenite were studied by X-ray diffraction stress analysis which is performed on the basis of the sin2ψ method and the lattice parameters were explored by Rietveld method. The results reveal that difference changes of depth residual compressive stress profiles between ferrite and austenite under the same annealing condition are resulted from the diverse coefficient of thermal expansion, dislocation density, etc. for different phases in duplex stainless steel. The relaxations of depth residual stresses in austenite are more obvious than those in ferrite. The lattice parameters decrease in the surface layer with the extending of annealing time, however, they increase along the depth after annealing for 16min. The change of the depth lattice parameters can be ascribed to both thermal expansion and the relaxation of residual stress. The different changes of microstructure at elevated temperature between ferrite and austenite are discussed.

High Cycle Fatigue Performance in Laser Shock Peened TC4 Titanium Alloys Subjected to Foreign Object Damage

Science.gov (United States)

Luo, Sihai; Nie, Xiangfan; Zhou, Liucheng; Li, Yiming; He, Weifeng

2018-03-01

During their service, titanium alloys are likely to suffer from the foreign object damage (FOD), resulting in a decrease in their fatigue strength. Laser shock peening (LSP) has been proved to effectively increase the damage tolerance of military engine components by introducing a magnitude compressive residual stress in the near-surface layer of alloys. In this paper, smooth specimens of a TC4 titanium alloy were used and treated by LSP and subsequently exposed to FOD, which was simulated by firing a steel sphere with a nominal velocity of 300 m/s, at 90° with the leading edge of the LSP-treated region using a light gas gun. All impacted specimens were then subjected to fatigue loading. The results showed that LSP could effectively improve the fatigue strength of the damaged specimens. The effect of LSP on the fatigue strength was assessed through fracture observations, microhardness tests and residual stress analyses. The residual stresses due to the plastic deformation caused by LSP and the FOD impact, which were found to play a crucial role on the fatigue strength, were determined using the commercial software ABAQUS.

Tratamento cirúrgico em dois tempos do aneurisma toracoabdominal roto com prótese intraluminal sem sutura

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Rodrigo de Castro BERNARDES

1998-10-01

Full Text Available O tratamento cirúrgico dos aneurismas toracoabominais exige toracofreno laparotomia, períodos prolongados de pinçamento aórtico com isquemia visceral, sangramento abundante de difícil controle, complicações pulmonares, renais, neurológicas e distúrbios de coagulação com morbimortalidade muitas vezes proibitiva para pacientes de idade avançada, ou portadores de distúrbios respiratórios, renais ou cardíacos prévios. A rotura aumenta em muito a já elevada taxa de morbimortalidade. Crawford (1-3 e Borst (4 descreveram operação em dois tempos para tratamento de aneurisma que atinge mais de um segmento da aorta, com bons resultados. O objetivo de nosso trabalho é mostrar a técnica cirúrgica em dois tempos, empregando prótese intraluminal sem sutura (5, 6. Esta técnica nos proporciona uma operação menos agressiva por abordar somente o segmento roto da aorta, portanto apenas uma cavidade é manipulada (tórax ou abdome. A anastomose com prótese intraluminal reduz em muito o tempo de pinçamento da aorta e, conseqüentemente, a isquemia visceral, diminuindo, também, o sangramento. A redução da agressividade cirúrgica sobre estes pacientes já gravemente enfermos nos proporcionou bons resultados cirúrgicos.The surgical management of thoracoabdominal aneurysms requires thoracophrenic laparotomy, prolonged periods of aortic clamping with visceral ischemia, profuse bleeding leading to a difficult postoperative course with pulmonary, renal, neurological complications, coagulation disturbances and others. All this resulting in an elevated morbidity/mortality very often contraindicating it for the very elderly or those with prior respiratory, renal or cardiac symptoms. Rupture of this aneurysm greatly increases the already high rate of morbidity/mortality. Crawford and Borst have described a two-stage surgery with good results, for aneurysms that affect more than one segment of aorta. The objective of our report is to demonstrate

A long baseline global stereo matching based upon short baseline estimation

Science.gov (United States)

Li, Jing; Zhao, Hong; Li, Zigang; Gu, Feifei; Zhao, Zixin; Ma, Yueyang; Fang, Meiqi

2018-05-01

In global stereo vision, balancing the matching efficiency and computing accuracy seems to be impossible because they contradict each other. In the case of a long baseline, this contradiction becomes more prominent. In order to solve this difficult problem, this paper proposes a novel idea to improve both the efficiency and accuracy in global stereo matching for a long baseline. In this way, the reference images located between the long baseline image pairs are firstly chosen to form the new image pairs with short baselines. The relationship between the disparities of pixels in the image pairs with different baselines is revealed by considering the quantized error so that the disparity search range under the long baseline can be reduced by guidance of the short baseline to gain matching efficiency. Then, the novel idea is integrated into the graph cuts (GCs) to form a multi-step GC algorithm based on the short baseline estimation, by which the disparity map under the long baseline can be calculated iteratively on the basis of the previous matching. Furthermore, the image information from the pixels that are non-occluded under the short baseline but are occluded for the long baseline can be employed to improve the matching accuracy. Although the time complexity of the proposed method depends on the locations of the chosen reference images, it is usually much lower for a long baseline stereo matching than when using the traditional GC algorithm. Finally, the validity of the proposed method is examined by experiments based on benchmark datasets. The results show that the proposed method is superior to the traditional GC method in terms of efficiency and accuracy, and thus it is suitable for long baseline stereo matching.

Effect of Abrasive Waterjet Peening Surface Treatment of Steel Plates on the Strength of Single-Lap Adhesive Joints

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Kamil Anasiewicz

2017-09-01

Full Text Available The paper presents results of comparative study of shear strength of single–lap adhesive joints, depending on the method of surface preparation of steel plates with increased corrosion resistance. The method of preparing adherend surfaces is often one of the most important factors determining the strength of adhesive joints. Appropriate geometric surface development and cleaning of the surface enhances adhesion forces between adherend material and adhesive. One of the methods of shaping engineering materials is waterjet cutting, which in the AWJP – abrasive waterjet peening variant, serves to shape flat surfaces of the material by changing the roughness and introducing stresses into the surface layer. These changes are valuable when preparing adhesive joints. In the study, surface roughness parameters obtained with AWJP treatment, were analyzed in direct relation to the strength of the adhesive joint. As a consequence of the experimental results analysis, the increase in the strength of the adhesive joints was observed in a certain range of parameters used for AWJP treatment. A decrease in shear strength of adhesive joint with the most modified topography of overlap surface was observed.

Influence of specimen thickness on the fatigue behavior of notched steel plates subjected to laser shock peening

Science.gov (United States)

Granados-Alejo, V.; Rubio-González, C.; Vázquez-Jiménez, C. A.; Banderas, J. A.; Gómez-Rosas, G.

2018-05-01

The influence of specimen thickness on the fatigue crack initiation of 2205 duplex stainless steel notched specimens subjected to laser shock peening (LSP) was investigated. The purpose was to examine the effectiveness of LSP on flat components with different thicknesses. For the LSP treatment a Nd:YAG pulsed laser operating at 10 Hz with 1064 nm of wavelength was used; pulse density was 2500 pulses/cm2. The LSP setup was the waterjet arrangement without sample coating. Residual stress distribution as a function of depth was determined by the hole drilling method. Notched specimens 2, 3 and 4 mm thick were LSP treated on both faces and then fatigue loading was applied with R = 0.1. Experimental fatigue lives were compared with life predictions from finite element simulation. A good comparison of the predicted and experimental fatigue lives was observed. LSP finite element simulation helps in explaining the influence of thickness on fatigue lives in terms of equivalent plastic strain distribution variations associated with the change in thickness. It is demonstrated that specimen size effect is an important issue in applying LSP on real components. Reducing the specimen thickness, the fatigue life improvement induced by LSP is significantly increased. Fatigue life extension up to 300% is observed on thin specimens with LSP.

Developing RESRAD-BASELINE for environmental baseline risk assessment

International Nuclear Information System (INIS)

Cheng, Jing-Jy.

1995-01-01

RESRAD-BASELINE is a computer code developed at Argonne developed at Argonne National Laboratory for the US Department of Energy (DOE) to perform both radiological and chemical risk assessments. The code implements the baseline risk assessment guidance of the US Environmental Protection Agency (EPA 1989). The computer code calculates (1) radiation doses and cancer risks from exposure to radioactive materials, and (2) hazard indexes and cancer risks from exposure to noncarcinogenic and carcinogenic chemicals, respectively. The user can enter measured or predicted environmental media concentrations from the graphic interface and can simulate different exposure scenarios by selecting the appropriate pathways and modifying the exposure parameters. The database used by PESRAD-BASELINE includes dose conversion factors and slope factors for radionuclides and toxicity information and properties for chemicals. The user can modify the database for use in the calculation. Sensitivity analysis can be performed while running the computer code to examine the influence of the input parameters. Use of RESRAD-BASELINE for risk analysis is easy, fast, and cost-saving. Furthermore, it ensures in consistency in methodology for both radiological and chemical risk analyses

Microstructural response and grain refinement mechanism of commercially pure titanium subjected to multiple laser shock peening impacts

International Nuclear Information System (INIS)

Lu, J.Z.; Wu, L.J.; Sun, G.F.; Luo, K.Y.; Zhang, Y.K.; Cai, J.; Cui, C.Y.; Luo, X.M.

2017-01-01

The microstructural response and grain subdivision process in commercially pure (CP) titanium subjected to multiple laser shock peening (LSP) impacts were investigated by means of optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations. The micro-hardness curves as a function of the impact time were also determined. The deformation-induced grain refinement mechanism of the close-packed hexagonal (hcp) material by laser shock wave was subsequently analyzed. Experimental results showed that uniform equiaxed grains with an average size of less than 50 nm were generated due to the ultra-high plastic strain induced by multiple LSP impacts. Special attention was paid to four types of novel deformation-induced microstructural features, including a layered slip band in the tension deformation zone, and inverse-transformation martensite, micro-twin grating and micro-twin collision in the compression deformation zone. Furthermore, the grain refinement mechanism in the near-surface layer of CP titanium subjected to multiple LSP impacts contains two types of simultaneous subdivision modes: multi-directional mechanical twin (MT)-MT intersections at (sub)micrometer scale, and the intersection between longitudinal secondary MTs and transverse dislocation walls at nanometer scale. In addition, both grain refinement (nanocrystallization) and the existence of a small amount of inverse-transformation martensite induced by multiple LSP impacts contribute to an increase in the micro-hardness of the near-surface layer.

Effects of laser peening treatment on high cycle fatigue and crack propagation behaviors in austenitic stainless steel

International Nuclear Information System (INIS)

Masaki, Kiyotaka; Ochi, Yasuo; Matsumura, Takashi; Ikarashi, Takaaki; Sano, Yuji

2010-01-01

Laser peening without protective coating (LPwC) treatment is one of surface enhancement techniques using an impact wave of high pressure plasma induced by laser pulse irradiation. High compressive residual stress was induced by the LPwC treatment on the surface of low-carbon type austenitic stainless steel SUS316L. The affected depth reached about 1mm from the surface. High cycle fatigue tests with four-points rotating bending loading were carried out to confirm the effects of the LPwC treatment on fatigue strength and surface fatigue crack propagation behaviors. The fatigue strength was remarkably improved by the LPwC treatment over the whole regime of fatigue life up to 10 8 cycles. Specimens with a pre-crack from a small artificial hole due to fatigue loading were used for the quantitative study on the effect of the LPwC treatment. The fracture mechanics investigation on the pre-cracked specimens showed that the LPwC treatment restrained the further propagation of the pre-crack if the stress intensity factor range ΔK on the crack tip was less than 7.6 MPa√m. Surface cracks preferentially propagated into the depth direction as predicted through ΔK analysis on the crack by taking account of the compressive residual stresses due to the LPwC treatment. (author)

Minimization of spurious strains by using a Si bent-perfect-crystal monochromator: neutron surface strain scanning of a shot-peened sample

Science.gov (United States)

Rebelo Kornmeier, Joana; Gibmeier, Jens; Hofmann, Michael

2011-06-01

Neutron strain measurements are critical at the surface. When scanning close to a sample surface, aberration peak shifts arise due to geometrical and divergence effects. These aberration peak shifts can be of the same order as the peak shifts related to residual strains. In this study it will be demonstrated that by optimizing the horizontal bending radius of a Si (4 0 0) monochromator, the aberration peak shifts from surface effects can be strongly reduced. A stress-free sample of fine-grained construction steel, S690QL, was used to find the optimal instrumental conditions to minimize aberration peak shifts. The optimized Si (4 0 0) monochromator and instrument settings were then applied to measure the residual stress depth gradient of a shot-peened SAE 4140 steel sample to validate the effectiveness of the approach. The residual stress depth profile is in good agreement with results obtained by x-ray diffraction measurements from an international round robin test (BRITE-EURAM-project ENSPED). The results open very promising possibilities to bridge the gap between x-ray diffraction and conventional neutron diffraction for non-destructive residual stress analysis close to surfaces.

Minimization of spurious strains by using a Si bent-perfect-crystal monochromator: neutron surface strain scanning of a shot-peened sample

International Nuclear Information System (INIS)

Rebelo Kornmeier, Joana; Hofmann, Michael; Gibmeier, Jens

2011-01-01

Neutron strain measurements are critical at the surface. When scanning close to a sample surface, aberration peak shifts arise due to geometrical and divergence effects. These aberration peak shifts can be of the same order as the peak shifts related to residual strains. In this study it will be demonstrated that by optimizing the horizontal bending radius of a Si (4 0 0) monochromator, the aberration peak shifts from surface effects can be strongly reduced. A stress-free sample of fine-grained construction steel, S690QL, was used to find the optimal instrumental conditions to minimize aberration peak shifts. The optimized Si (4 0 0) monochromator and instrument settings were then applied to measure the residual stress depth gradient of a shot-peened SAE 4140 steel sample to validate the effectiveness of the approach. The residual stress depth profile is in good agreement with results obtained by x-ray diffraction measurements from an international round robin test (BRITE-EURAM-project ENSPED). The results open very promising possibilities to bridge the gap between x-ray diffraction and conventional neutron diffraction for non-destructive residual stress analysis close to surfaces

Effect of structure evolution induced by ultrasonic peening on the corrosion behavior of AISI-321 stainless steel

International Nuclear Information System (INIS)

Mordyuk, B.N.; Prokopenko, G.I.; Vasylyev, M.A.; Iefimov, M.O.

2007-01-01

A nanocrystalline surface layer was produced on an AISI-321 stainless steel by severe plastic deformation via ultrasonic peening (UP). The microstructural evolution of the surface layer was characterized by means of X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM). The volume fraction of strain-induced α-martensite as a function of the effective strain (e-bar) was evaluated quantitatively using XRD and magnetic measurements. Considering the e-bar magnitudes and the TEM data obtained, it is concluded that a grain refinement of austenitic structure passes ahead of the α-martensite formation, particularly in the top surface layer. The nanocrystalline austenitic grain structure (mean grain size∼15nm) was observed at e-bar=0.45, while the startup of the strain-induced martensitic transformation was revealed at the strain extent of 0.62. The nanostructured surface layer formed after straining to e-bar=0.8 already contains mainly the martensite nanograins characterized by an average size of about 10nm. Grain size increased gradually up to 60nm within the layer containing both austenite and martensite phases at a depth of about 30μm from the treated surface. Both the microhardness behavior of the stainless steel surface and its corrosion performance in 3.5% NaCl solution can be enhanced by the UP. They are shown to be in correlation with: (i) the grain refinement process and (ii) the increase in the volume fraction of strain-induced α-martensite

The Role of Cold Work in Eddy Current Residual Stress Measurements in Shot-Peened Nickel-Base Superalloys

International Nuclear Information System (INIS)

Yu, F.; Nagy, P. B.

2006-01-01

Recently, it was shown that eddy current methods can be adapted to residual stress measurement in shot-peened nickel-base superalloys. However, experimental evidence indicates that the piezoresistivity effect is simply not high enough to account for the observed apparent eddy current conductivity (AECC) increase. At the same time, X-ray diffraction data indicates that 'cold work' lingers even when the residual stress is fully relaxed and the excess AECC is completely gone. It is impossible to account for both observations with a single coherent explanation unless we assume that instead of a single 'cold work' effect, there are two varieties of cold work; type-A and type-B. Type-A cold work (e.g., changes in the microscopic homogeneity of the material) is not detected by X-ray diffraction as it does not significantly affect the beam width, but causes substantial conductivity change and exhibits strong thermal relaxation. Type-B cold work (e.g., dislocations) is detected by X-ray, but causes little or no conductivity change and exhibits weak thermal relaxation. Based on the assumption of two separate cold-work variables and that X-ray diffraction results indicate the presence of type-B, but not type-A, all observed phenomena can be explained. If this working hypothesis is proven right, the separation of residual stress and type-A cold work is less critical because they both relax much earlier and much faster than type-B cold work

Improving tribological performance of gray cast iron by laser peening in dynamic strain aging temperature regime

Science.gov (United States)

Feng, Xu; Zhou, Jianzhong; Mei, Yufen; Huang, Shu; Sheng, Jie; Zhu, Weili

2015-09-01

A high and stable brake disc friction coefficient is needed for automobile safety, while the coefficient degrades due to elevated temperature during the braking process. There is no better solution except changes in material composition and shape design optimization. In the dynamic strain aging(DSA) temperature regime of gray cast iron, micro-dimples with different dimple depth over diameter and surface area density are fabricated on the material surface by laser peening(LP) which is an LST method. Friction behavior and wear mechanism are investigated to evaluate the effects of surface texturing on the tribological performance of specimens under dry conditions. Through LP impacts assisted by DSA, the friction coefficients of the LPed specimens increase noticeably both at room temperature and elevated temperature in comparison to untreated specimens. Moreover, the coefficient of specimen with dimple depth over diameter of 0.03 and surface area density of 30% is up to 0.351 at room temperature, which dramatically rises up to 1.33 times that of untextured specimen and the value is still up to 0.3305 at 400°C with an increasing ratio of 35% compared to that of untreated specimen. The surface of textured specimen shows better wear resistance compared to untreated specimen. Wear mechanism includes adhesive wear, abrasive wear and oxidation wear. It is demonstrated that LP assisted by DSA can substantially improve wear resistance, raise the friction coefficient as well as its stability of gray cast iron under elevated temperatures. Heat fade and premature wear can be effectively relieved by this surface modification method.

Complicaciones por rotura de aneurismas cerebrales en pacientes operados Hospital Nacional Alberto Sabogal Sologuren 2006 - 2014

OpenAIRE

Coasaca Torres, Juan Amilcar

2016-01-01

Determinar las complicaciones que se presentan en el periodo preoperatorio, intraoperatorio y postoperatorio de los pacientes operados de aneurisma cerebral roto en el Hospital Nacional Alberto Sabogal Sologuren de 2006 a 2014. Para lo que se realizó un estudio cuantitativo, observacional, descriptivo, transversal y retrospectivo. Se revisaron las Historias Clínicas de los pacientes operados (clipaje) de aneurisma cerebral roto, que reunían los criterios de inclusión. La data obtenida fue eva...

Program Baseline Change Control Procedure

International Nuclear Information System (INIS)

1993-02-01

This procedure establishes the responsibilities and process for approving initial issues of and changes to the technical, cost, and schedule baselines, and selected management documents developed by the Office of Civilian Radioactive Waste Management (OCRWM) for the Civilian Radioactive Waste Management System. This procedure implements the OCRWM Baseline Management Plan and DOE Order 4700.1, Chg 1. It streamlines the change control process to enhance integration, accountability, and traceability of Level 0 and Level I decisions through standardized Baseline Change Proposal (BCP) forms to be used by the Level 0, 1, 2, and 3 Baseline Change Control Boards (BCCBs) and to be tracked in the OCRWM-wide Configuration Information System (CIS) Database.This procedure applies to all technical, cost, and schedule baselines controlled by the Energy System Acquisition Advisory Board (ESAAB) BCCB (Level 0) and, OCRWM Program Baseline Control Board (PBCCB) (Level 1). All baseline BCPs initiated by Level 2 or lower BCCBs, which require approval from ESAAB or PBCCB, shall be processed in accordance with this procedure. This procedure also applies to all Program-level management documents controlled by the OCRWM PBCCB

Program reference schedule baseline

International Nuclear Information System (INIS)

1986-07-01

This Program Reference Schedule Baseline (PRSB) provides the baseline Program-level milestones and associated schedules for the Civilian Radioactive Waste Management Program. It integrates all Program-level schedule-related activities. This schedule baseline will be used by the Director, Office of Civilian Radioactive Waste Management (OCRWM), and his staff to monitor compliance with Program objectives. Chapter 1 includes brief discussions concerning the relationship of the PRSB to the Program Reference Cost Baseline (PRCB), the Mission Plan, the Project Decision Schedule, the Total System Life Cycle Cost report, the Program Management Information System report, the Program Milestone Review, annual budget preparation, and system element plans. Chapter 2 includes the identification of all Level 0, or Program-level, milestones, while Chapter 3 presents and discusses the critical path schedules that correspond to those Level 0 milestones

CryoSat SAR/SARin Level1b products: assessment of BaselineC and improvements towards BaselineD

Science.gov (United States)

Scagliola, Michele; Fornari, Marco; Bouffard, Jerome; Parrinello, Tommaso

2017-04-01

CryoSat was launched on the 8th April 2010 and is the first European ice mission dedicated to the monitoring of precise changes in the thickness of polar ice sheets and floating sea ice. Cryosat carries an innovative radar altimeter called the Synthetic Aperture Interferometric Altimeter (SIRAL), that transmits pulses at a high pulse repetition frequency thus making the received echoes phase coherent and suitable for azimuth processing. This allows to reach a significantly improved along track resolution with respect to traditional pulse-width limited altimeters. CryoSat is the first altimetry mission operating in SAR mode and continuous improvements in the Level1 Instrument Processing Facility (IPF1) are being identified, tested and validated in order to improve the quality of the Level1b products. The current IPF, Baseline C, was released in operation in April 2015 and the second CryoSat reprocessing campaign was jointly initiated, taking benefit of the upgrade implemented in the IPF1 processing chain but also of some specific configurations for the calibration corrections. In particular, the CryoSat Level1b BaselineC products generated in the framework of the second reprocessing campaign include refined information for what concerns the mispointing angles and the calibration corrections. This poster will thus detail thus the evolutions that are currently planned for the CryoSat BaselineD SAR/SARin Level1b products and the corresponding quality improvements that are expected.

DairyBISS Baseline report

NARCIS (Netherlands)

Buizer, N.N.; Berhanu, Tinsae; Murutse, Girmay; Vugt, van S.M.

2015-01-01

This baseline report of the Dairy Business Information Service and Support (DairyBISS) project presents the findings of a baseline survey among 103 commercial farms and 31 firms and advisors working in the dairy value chain. Additional results from the survey among commercial dairy farms are

Numerical simulation of laser shock in the presence of the initial state due to welding

International Nuclear Information System (INIS)

Julan, Emricka

2014-01-01

Surface treatments as laser shock peening offer the possibility to reduce tensile stresses or to generate compressive stresses in order to prevent crack initiation or reduce crack growth rate in particular in the areas where tension weld residual stresses are present. Laser shock peening may be applied on different metallic components to prevent stress corrosion cracking of Inconel 600 and high cycle thermal fatigue of austenitic stainless steels. The main aim of the PhD thesis is to develop the numerical simulation of laser peening. In the first section, axisymmetrical and 3D numerical models for one or several pulses have been developed in Code Aster and Europlexus softwares. These models were validated by experimental tests carried out in PIMM-ENSAM laboratory. Parameters identification of Johnson-Cook constitutive law was carried out for Inconel 600 at high strain rates. Moreover a new test was proposed which allowed proving the isotropic behavior of Inconel 600 at high strain rates. A modification of the Johnson-Cook constitutive law was also proposed, to take into account in a new way the sensitivity of the law to high strain rates. The second section of the thesis concerns a study on the effect of an initial state of welding on residual stresses after application of laser peening. We could conclude that this initial state has no strong influence on final residual stresses. Finally, a qualitative study on the effect of strain hardening induced by laser peening on fatigue life of stainless steels was undertaken, which shows the advantage of laser peening on shot peening due to smaller strain hardening created by laser peening. (author)

Baseline rationing

DEFF Research Database (Denmark)

Hougaard, Jens Leth; Moreno-Ternero, Juan D.; Østerdal, Lars Peter Raahave

The standard problem of adjudicating conflicting claims describes a situation in which a given amount of a divisible good has to be allocated among agents who hold claims against it exceeding the available amount. This paper considers more general rationing problems in which, in addition to claims...... to international protocols for the reduction of greenhouse emissions, or water distribution in drought periods. We define a family of allocation methods for such general rationing problems - called baseline rationing rules - and provide an axiomatic characterization for it. Any baseline rationing rule within...... the family is associated with a standard rule and we show that if the latter obeys some properties reflecting principles of impartiality, priority and solidarity, the former obeys them too....

Baseline restoration using current conveyors

International Nuclear Information System (INIS)

Morgado, A.M.L.S.; Simoes, J.B.; Correia, C.M.

1996-01-01

A good performance of high resolution nuclear spectrometry systems, at high pulse rates, demands restoration of baseline between pulses, in order to remove rate dependent baseline shifts. This restoration is performed by circuits named baseline restorers (BLRs) which also remove low frequency noise, such as power supply hum and detector microphonics. This paper presents simple circuits for baseline restoration based on a commercial current conveyor (CCII01). Tests were performed, on two circuits, with periodic trapezoidal shaped pulses in order to measure the baseline restoration for several pulse rates and restorer duty cycles. For the current conveyor based Robinson restorer, the peak shift was less than 10 mV, for duty cycles up to 60%, at high pulse rates. Duty cycles up to 80% were also tested, being the maximum peak shift 21 mV. The peak shift for the current conveyor based Grubic restorer was also measured. The maximum value found was 30 mV at 82% duty cycle. Keeping the duty cycle below 60% improves greatly the restorer performance. The ability of both baseline restorer architectures to reject low frequency modulation is also measured, with good results on both circuits

Large short-baseline νμ disappearance

International Nuclear Information System (INIS)

Giunti, Carlo; Laveder, Marco

2011-01-01

We analyze the LSND, KARMEN, and MiniBooNE data on short-baseline ν μ →ν e oscillations and the data on short-baseline ν e disappearance obtained in the Bugey-3 and CHOOZ reactor experiments in the framework of 3+1 antineutrino mixing, taking into account the MINOS observation of long-baseline ν μ disappearance and the KamLAND observation of very-long-baseline ν e disappearance. We show that the fit of the data implies that the short-baseline disappearance of ν μ is relatively large. We obtain a prediction of an effective amplitude sin 2 2θ μμ > or approx. 0.1 for short-baseline ν μ disappearance generated by 0.2 2 2 , which could be measured in future experiments.

Investigation on the Tribological Behavior of Arc-Sprayed and Hammer-Peened Coatings Using Tungsten Carbide Cored Wires

Science.gov (United States)

Tillmann, W.; Hagen, L.; Schröder, P.

2017-01-01

Due to their outstanding properties, WC-W2C iron-based cermet coatings are widely used in the field of wear protection. Regarding commonly used WC-W2C reinforced coating systems, it has been reported that their tribological behavior is mainly determined by the carbide grain size fraction. Although the manufacturing route for arc-sprayed WC-W2C cermet coatings is in an advanced state, there is still a lack of knowledge concerning the performance of cored wires with tungsten carbides as filling material and their related coating properties when post-treatment processes are used such as machine hammer peening (MHP). A major objective was to characterize WC-W2C FeCMnSi coatings, deposited with different carbide grain size fractions as a filling using cored wires, with respect to their tribological behavior. Moreover, deposits derived from cored wires with a different amount of hard phases are investigated. According to this, polished MHP surfaces are compared to as-sprayed and polished samples by means of metallographic investigations. With the use of ball-on-disk and dry rubber wheel tests, dry sliding and rolling wear effects on a microscopic level are scrutinized. It has been shown that the MHP process leads to a densification of the microstructure formation. For dry sliding experiments, the MHP coatings obtain lower wear resistances, but lower coefficients of friction than the conventional coatings. In view of abrasion tests, the MHP coatings possess an improved wear resistance. Strain hardening effects at the subsurface area were revealed by the mechanical response using nanoindentation. However, the MHP process has caused a cracking of embedded carbides, which favor breakouts, leading to advanced third-body wear.

TAPIR--Finnish national geochemical baseline database.

Science.gov (United States)

Jarva, Jaana; Tarvainen, Timo; Reinikainen, Jussi; Eklund, Mikael

2010-09-15

In Finland, a Government Decree on the Assessment of Soil Contamination and Remediation Needs has generated a need for reliable and readily accessible data on geochemical baseline concentrations in Finnish soils. According to the Decree, baseline concentrations, referring both to the natural geological background concentrations and the diffuse anthropogenic input of substances, shall be taken into account in the soil contamination assessment process. This baseline information is provided in a national geochemical baseline database, TAPIR, that is publicly available via the Internet. Geochemical provinces with elevated baseline concentrations were delineated to provide regional geochemical baseline values. The nationwide geochemical datasets were used to divide Finland into geochemical provinces. Several metals (Co, Cr, Cu, Ni, V, and Zn) showed anomalous concentrations in seven regions that were defined as metal provinces. Arsenic did not follow a similar distribution to any other elements, and four arsenic provinces were separately determined. Nationwide geochemical datasets were not available for some other important elements such as Cd and Pb. Although these elements are included in the TAPIR system, their distribution does not necessarily follow the ones pre-defined for metal and arsenic provinces. Regional geochemical baseline values, presented as upper limit of geochemical variation within the region, can be used as trigger values to assess potential soil contamination. Baseline values have also been used to determine upper and lower guideline values that must be taken into account as a tool in basic risk assessment. If regional geochemical baseline values are available, the national guideline values prescribed in the Decree based on ecological risks can be modified accordingly. The national geochemical baseline database provides scientifically sound, easily accessible and generally accepted information on the baseline values, and it can be used in various

Quantum numbers and band topology of nanotubes

Energy Technology Data Exchange (ETDEWEB)

Damnjanovic, M [Faculty of Physics, University of Belgrade, POB 368, 11001 Belgrade (Yugoslavia); Milosevic, I [Faculty of Physics, University of Belgrade, POB 368, 11001 Belgrade (Yugoslavia); Vukovic, T [Faculty of Physics, University of Belgrade, POB 368, 11001 Belgrade (Yugoslavia); Maultzsch, J [Institut fuer Festkoerper Physik, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany)

2003-05-30

Nanotubes as well as polymers and quasi-1D subsystems of 3D crystals have line group symmetry. This allows two types of quantum numbers: roto-translational and helical. The roto-translational quantum numbers are linear and total angular (not conserved) momenta, while the helical quantum numbers are helical and complementary angular momenta. Their mutual relations determine some topological properties of energy bands, such as systematic band sticking or van Hove singularities related to parities. The importance of these conclusions is illustrated by the optical absorption in carbon nanotubes: parity may prevent absorption peaks at van Hove singularities.

Quantum numbers and band topology of nanotubes

International Nuclear Information System (INIS)

Damnjanovic, M; Milosevic, I; Vukovic, T; Maultzsch, J

2003-01-01

Nanotubes as well as polymers and quasi-1D subsystems of 3D crystals have line group symmetry. This allows two types of quantum numbers: roto-translational and helical. The roto-translational quantum numbers are linear and total angular (not conserved) momenta, while the helical quantum numbers are helical and complementary angular momenta. Their mutual relations determine some topological properties of energy bands, such as systematic band sticking or van Hove singularities related to parities. The importance of these conclusions is illustrated by the optical absorption in carbon nanotubes: parity may prevent absorption peaks at van Hove singularities

Quantum numbers and band topology of nanotubes

CERN Document Server

Damnjanovic, M; Vukovic, T; Maultzsch, J

2003-01-01

Nanotubes as well as polymers and quasi-1D subsystems of 3D crystals have line group symmetry. This allows two types of quantum numbers: roto-translational and helical. The roto-translational quantum numbers are linear and total angular (not conserved) momenta, while the helical quantum numbers are helical and complementary angular momenta. Their mutual relations determine some topological properties of energy bands, such as systematic band sticking or van Hove singularities related to parities. The importance of these conclusions is illustrated by the optical absorption in carbon nanotubes: parity may prevent absorption peaks at van Hove singularities.

Mechanisms of Residual Stress Generation in Mechanical Surface Treatment: the Role of Cyclic Plasticity and Texture

Science.gov (United States)

2015-08-24

Abstract This project investigated the response of two aluminium alloys to laser shock peening, studying the effects of hardening response through...Barter, S.A. & Ye, L. 2007, "The effect of laser power density on the fatigue life of laser-shock-peened 7050 aluminium alloy ", Fatigue & Fracture of...Wu, G., Yang, J.M. & Pan, T. 2004, "Laser shock peening on fatigue crack growth behaviour of aluminium alloy ", Fatigue & Fracture of Engineering

40 CFR 1042.825 - Baseline determination.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Baseline determination. 1042.825... Provisions for Remanufactured Marine Engines § 1042.825 Baseline determination. (a) For the purpose of this... not valid. (f) Use good engineering judgment for all aspects of the baseline determination. We may...

Oscillation Baselining and Analysis Tool

Energy Technology Data Exchange (ETDEWEB)

2017-03-27

PNNL developed a new tool for oscillation analysis and baselining. This tool has been developed under a new DOE Grid Modernization Laboratory Consortium (GMLC) Project (GM0072 - “Suite of open-source applications and models for advanced synchrophasor analysis”) and it is based on the open platform for PMU analysis. The Oscillation Baselining and Analysis Tool (OBAT) performs the oscillation analysis and identifies modes of oscillations (frequency, damping, energy, and shape). The tool also does oscillation event baselining (fining correlation between oscillations characteristics and system operating conditions).

33 CFR 2.20 - Territorial sea baseline.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Territorial sea baseline. 2.20... JURISDICTION Jurisdictional Terms § 2.20 Territorial sea baseline. Territorial sea baseline means the line.... Normally, the territorial sea baseline is the mean low water line along the coast of the United States...

Program Baseline Change Control Board charter

International Nuclear Information System (INIS)

1993-02-01

The purpose of this Charter is to establish the Program Baseline Change Control Board (PBCCB) for the Office of Civilian Radioactive Waste Management (OCRWM) Program, and to describe its organization, responsibilities, and basic methods of operation. Guidance for implementing this Charter is provided by the OCRWM Baseline Management Plan (BMP) and OCRWM Program Baseline Change Control Procedure

Establishing a store baseline during interim storage of waste packages and a review of potential technologies for base-lining

Energy Technology Data Exchange (ETDEWEB)

McTeer, Jennifer; Morris, Jenny; Wickham, Stephen [Galson Sciences Ltd. Oakham, Rutland (United Kingdom); Bolton, Gary [National Nuclear Laboratory Risley, Warrington (United Kingdom); McKinney, James; Morris, Darrell [Nuclear Decommissioning Authority Moor Row, Cumbria (United Kingdom); Angus, Mike [National Nuclear Laboratory Risley, Warrington (United Kingdom); Cann, Gavin; Binks, Tracey [National Nuclear Laboratory Sellafield (United Kingdom)

2013-07-01

Interim storage is an essential component of the waste management lifecycle, providing a safe, secure environment for waste packages awaiting final disposal. In order to be able to monitor and detect change or degradation of the waste packages, storage building or equipment, it is necessary to know the original condition of these components (the 'waste storage system'). This paper presents an approach to establishing the baseline for a waste-storage system, and provides guidance on the selection and implementation of potential base-lining technologies. The approach is made up of two sections; assessment of base-lining needs and definition of base-lining approach. During the assessment of base-lining needs a review of available monitoring data and store/package records should be undertaken (if the store is operational). Evolutionary processes (affecting safety functions), and their corresponding indicators, that can be measured to provide a baseline for the waste-storage system should then be identified in order for the most suitable indicators to be selected for base-lining. In defining the approach, identification of opportunities to collect data and constraints is undertaken before selecting the techniques for base-lining and developing a base-lining plan. Base-lining data may be used to establish that the state of the packages is consistent with the waste acceptance criteria for the storage facility and to support the interpretation of monitoring and inspection data collected during store operations. Opportunities and constraints are identified for different store and package types. Technologies that could potentially be used to measure baseline indicators are also reviewed. (authors)

Hazard Baseline Downgrade Effluent Treatment Facility

International Nuclear Information System (INIS)

Blanchard, A.

1998-01-01

This Hazard Baseline Downgrade reviews the Effluent Treatment Facility, in accordance with Department of Energy Order 5480.23, WSRC11Q Facility Safety Document Manual, DOE-STD-1027-92, and DOE-EM-STD-5502-94. It provides a baseline grouping based on the chemical and radiological hazards associated with the facility. The Determination of the baseline grouping for ETF will aid in establishing the appropriate set of standards for the facility

Laser shock peening without coating induced residual stress distribution, wettability characteristics and enhanced pitting corrosion resistance of austenitic stainless steel

Science.gov (United States)

Prabhakaran, S.; Kulkarni, Aniket; Vasanth, G.; Kalainathan, S.; Shukla, Pratik; Vasudevan, Vijay K.

2018-01-01

Low energy laser shock peening without coating (LSPwC) was conducted on AISI 304 austenitic stainless steel specimens with varying pulse densities or overlapping. Highest magnitude of compressive residual stress (CRS) was achieved for an optimized pulse density of 2500 pulses/cm2 (75% overlapping). The 2-D and 3-D topographical analysis were indicative of the fact that controlled roughening of the surface was achieved after the LSPwC process. After the LSPwC process, the hydrophilic unpeened surface was converted into the hydrophobic surface, thus decreasing the wettability characteristics of the surface. The X-ray diffraction (XRD) results reveal that there is a beginning of the martensite transformation and the rise in the intensity value of the peaks after LSPwC indicates the presence of compressive residual stresses induced in the specimen. The optical microscope and high-resolution transmission electron microscope results provided evidence of grain refinement and deformation induced refinement features such as multidirectional mechanical twinning, dislocations lines, micro shear cells and stacking faults in the near and sub-surface areas. The average hardness value of the LSPwC specimens was found to be increased by 28% more than the untreated specimen. The potentiodynamic polarization revealed that there was a considerable amount of increase in the pitting corrosion resistance after the LSPwC process, thus, supporting to extend the fatigue life of the specimen. The electrochemical impedance spectroscopic (EIS) analysis depicts that the LSPwC process supports the formation of the strong passivation layer in 3.5% NaCl solution.

Electromyographic permutation entropy quantifies diaphragmatic denervation and reinnervation.

Directory of Open Access Journals (Sweden)

Christopher Kramer

Full Text Available Spontaneous reinnervation after diaphragmatic paralysis due to trauma, surgery, tumors and spinal cord injuries is frequently observed. A possible explanation could be collateral reinnervation, since the diaphragm is commonly double-innervated by the (accessory phrenic nerve. Permutation entropy (PeEn, a complexity measure for time series, may reflect a functional state of neuromuscular transmission by quantifying the complexity of interactions across neural and muscular networks. In an established rat model, electromyographic signals of the diaphragm after phrenicotomy were analyzed using PeEn quantifying denervation and reinnervation. Thirty-three anesthetized rats were unilaterally phrenicotomized. After 1, 3, 9, 27 and 81 days, diaphragmatic electromyographic PeEn was analyzed in vivo from sternal, mid-costal and crural areas of both hemidiaphragms. After euthanasia of the animals, both hemidiaphragms were dissected for fiber type evaluation. The electromyographic incidence of an accessory phrenic nerve was 76%. At day 1 after phrenicotomy, PeEn (normalized values was significantly diminished in the sternal (median: 0.69; interquartile range: 0.66-0.75 and mid-costal area (0.68; 0.66-0.72 compared to the non-denervated side (0.84; 0.78-0.90 at threshold p<0.05. In the crural area, innervated by the accessory phrenic nerve, PeEn remained unchanged (0.79; 0.72-0.86. During reinnervation over 81 days, PeEn normalized in the mid-costal area (0.84; 0.77-0.86, whereas it remained reduced in the sternal area (0.77; 0.70-0.81. Fiber type grouping, a histological sign for reinnervation, was found in the mid-costal area in 20% after 27 days and in 80% after 81 days. Collateral reinnervation can restore diaphragm activity after phrenicotomy. Electromyographic PeEn represents a new, distinctive assessment characterizing intramuscular function following denervation and reinnervation.

10 CFR 850.20 - Baseline beryllium inventory.

Science.gov (United States)

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false Baseline beryllium inventory. 850.20 Section 850.20 Energy... Baseline beryllium inventory. (a) The responsible employer must develop a baseline inventory of the... inventory, the responsible employer must: (1) Review current and historical records; (2) Interview workers...

40 CFR 80.92 - Baseline auditor requirements.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Baseline auditor requirements. 80.92... (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Anti-Dumping § 80.92 Baseline auditor requirements. (a... determination methodology, resulting baseline fuel parameter, volume and emissions values verified by an auditor...

Integrated planning: A baseline development perspective

International Nuclear Information System (INIS)

Clauss, L.; Chang, D.

1994-01-01

The FEMP Baseline establishes the basis for integrating environmental activity technical requirements with their cost and schedule elements. The result is a path forward to successfully achieving the FERMCO mission. Specific to cost management, the FEMP Baseline has been incorporate into the FERMCO Project Control System (PCS) to provide a time-phased budget plan against which contractor performance is measured with an earned value management system. The result is the Performance Measurement Baseline (PMB), an important tool for keeping cost under control

Physics with a very long neutrino factory baseline

International Nuclear Information System (INIS)

Gandhi, Raj; Winter, Walter

2007-01-01

We discuss the neutrino oscillation physics of a very long neutrino factory baseline over a broad range of lengths (between 6000 km and 9000 km), centered on the 'magic baseline' (∼7500 km) where correlations with the leptonic CP phase are suppressed by matter effects. Since the magic baseline depends only on the density, we study the impact of matter density profile effects and density uncertainties over this range, and the impact of detector locations off the optimal baseline. We find that the optimal constant density describing the physics over this entire baseline range is about 5% higher than the average matter density. This implies that the magic baseline is significantly shorter than previously inferred. However, while a single detector optimization requires fine-tuning of the (very long) baseline length, its combination with a near detector at a shorter baseline is much less sensitive to the far detector location and to uncertainties in the matter density. In addition, we point out different applications of this baseline which go beyond its excellent correlation and degeneracy resolution potential. We demonstrate that such a long baseline assists in the improvement of the θ 13 precision and in the resolution of the octant degeneracy. Moreover, we show that the neutrino data from such a baseline could be used to extract the matter density along the profile up to 0.24% at 1σ for large sin 2 2θ 13 , providing a useful discriminator between different geophysical models

Vereplekid punasel vaibal / Jaak Lõhmus

Index Scriptorium Estoniae

Lõhmus, Jaak, 1955-

2009-01-01

62. Cannes'i festivali filmidest : Pedro Almodovari "Katkirebitud embused" ("Los abrazos rotos"), Lars von Trieri "Antikristus" ("Antichrist"), Quentin Tarantino "Vääritud tõprad" ("Inglourious Basterds")

Large-baseline InSAR for precise topographic mapping: a framework for TanDEM-X large-baseline data

Directory of Open Access Journals (Sweden)

M. Pinheiro

2017-09-01

Full Text Available The global Digital Elevation Model (DEM resulting from the TanDEM-X mission provides information about the world topography with outstanding precision. In fact, performance analysis carried out with the already available data have shown that the global product is well within the requirements of 10 m absolute vertical accuracy and 2 m relative vertical accuracy for flat to moderate terrain. The mission's science phase took place from October 2014 to December 2015. During this phase, bistatic acquisitions with across-track separation between the two satellites up to 3.6 km at the equator were commanded. Since the relative vertical accuracy of InSAR derived elevation models is, in principle, inversely proportional to the system baseline, the TanDEM-X science phase opened the doors for the generation of elevation models with improved quality with respect to the standard product. However, the interferometric processing of the large-baseline data is troublesome due to the increased volume decorrelation and very high frequency of the phase variations. Hence, in order to fully profit from the increased baseline, sophisticated algorithms for the interferometric processing, and, in particular, for the phase unwrapping have to be considered. This paper proposes a novel dual-baseline region-growing framework for the phase unwrapping of the large-baseline interferograms. Results from two experiments with data from the TanDEM-X science phase are discussed, corroborating the expected increased level of detail of the large-baseline DEMs.

The H + HeH(+) → He + H2(+) reaction from the ultra-cold regime to the three-body breakup: exact quantum mechanical integral cross sections and rate constants.

Science.gov (United States)

De Fazio, Dario

2014-06-21

In this work, we present a quantum mechanical scattering study of the title reaction from 1 mK to 2000 K. Total integral cross sections and thermal rate constants are compared with previous theoretical and experimental data and with simpler theoretical models to understand the range of validity of the approximations used in the previous studies. The obtained quantum reactive observables have been found to be nearly insensitive to the roto-vibrational energy of the reactants at high temperatures. More sensitive to the reactant's roto-vibrational energy are the data in the cold and ultra-cold regimes. The implications of the new data presented here in the early universe scenario are also discussed and analyzed.

The TDAQ Baseline Architecture

CERN Multimedia

Wickens, F J

The Trigger-DAQ community is currently busy preparing material for the DAQ, HLT and DCS TDR. Over the last few weeks a very important step has been a series of meetings to complete agreement on the baseline architecture. An overview of the architecture indicating some of the main parameters is shown in figure 1. As reported at the ATLAS Plenary during the February ATLAS week, the main area where the baseline had not yet been agreed was around the Read-Out System (ROS) and details in the DataFlow. The agreed architecture has: Read-Out Links (ROLs) from the RODs using S-Link; Read-Out Buffers (ROB) sited near the RODs, mounted in a chassis - today assumed to be a PC, using PCI bus at least for configuration, control and monitoring. The baseline assumes data aggregation, in the ROB and/or at the output (which could either be over a bus or in the network). Optimization of the data aggregation will be made in the coming months, but the current model has each ROB card receiving input from 4 ROLs, and 3 such c...

Sustainability of compressive residual stress by stress improvement processes

International Nuclear Information System (INIS)

Nishikawa, Satoru; Okita, Shigeru; Yamaguchi, Atsunori

2013-01-01

Stress improvement processes are countermeasures against stress corrosion cracking in nuclear power plant components. It is necessary to confirm whether compressive residual stress induced by stress improvement processes can be sustained under operation environment. In order to evaluate stability of the compressive residual stress in 60-year operating conditions, the 0.07% cyclic strains of 200 times at 593 K were applied to the welded specimens, then a thermal aging treatment for 1.66x10 6 s at 673 K was carried out. As the result, it was confirmed that the compressive residual stresses were sustained on both surfaces of the dissimilar welds of austenitic stainless steel (SUS316L) and nickel base alloy (NCF600 and alloy 182) processed by laser peening (LP), water jet peening (WJP), ultrasonic shot peening (USP), shot peening (SP) and polishing under 60-year operating conditions. (author)

THE US LONG BASELINE NEUTRINO EXPERIMENT STUDY.

Energy Technology Data Exchange (ETDEWEB)

BISHAI,M.

2007-08-06

The US Long Baseline Neutrino Experiment Study was commissioned jointly by Brookhaven National Laboratory (BNL)and Fermi National Accelerator Laboratory (FNAL) to investigate the potential for future U.S. based long baseline neutrino oscillation experiments using MW class conventional neutrino beams that can be produced at FNAL. The experimental baselines are based on two possible detector locations: (1) off-axis to the existing FNAL NuMI beamline at baselines of 700 to 810 km and (2) NSF's proposed future Deep Underground Science and Engineering Laboratory (DUSEL) at baselines greater than 1000km. Two detector technologies are considered: a megaton class Water Cherenkov detector deployed deep underground at a DUSEL site, or a 100kT Liquid Argon Time-Projection Chamber (TPC) deployed on the surface at any of the proposed sites. The physics sensitivities of the proposed experiments are summarized. We find that conventional horn focused wide-band neutrino beam options from FNAL aimed at a massive detector with a baseline of > 1000km have the best sensitivity to CP violation and the neutrino mass hierarchy for values of the mixing angle {theta}{sub 13} down to 2{sup o}.

Long Baseline Observatory (LBO)

Data.gov (United States)

Federal Laboratory Consortium — The Long Baseline Observatory (LBO) comprises ten radio telescopes spanning 5,351 miles. It's the world's largest, sharpest, dedicated telescope array. With an eye...

Hanford Site technical baseline database. Revision 1

International Nuclear Information System (INIS)

Porter, P.E.

1995-01-01

This report lists the Hanford specific files (Table 1) that make up the Hanford Site Technical Baseline Database. Table 2 includes the delta files that delineate the differences between this revision and revision 0 of the Hanford Site Technical Baseline Database. This information is being managed and maintained on the Hanford RDD-100 System, which uses the capabilities of RDD-100, a systems engineering software system of Ascent Logic Corporation (ALC). This revision of the Hanford Site Technical Baseline Database uses RDD-100 version 3.0.2.2 (see Table 3). Directories reflect those controlled by the Hanford RDD-100 System Administrator. Table 4 provides information regarding the platform. A cassette tape containing the Hanford Site Technical Baseline Database is available

75 FR 66748 - Notice of Baseline Filings

Science.gov (United States)

2010-10-29

...- 000] Notice of Baseline Filings October 22, 2010. ONEOK Gas Transportation, L.L.C Docket No. PR11-68... above submitted a revised baseline filing of their Statement of Operating Conditions for services...

2016 Annual Technology Baseline (ATB) - Webinar Presentation

Energy Technology Data Exchange (ETDEWEB)

Cole, Wesley; Kurup, Parthiv; Hand, Maureen; Feldman, David; Sigrin, Benjamin; Lantz, Eric; Stehly, Tyler; Augustine, Chad; Turchi, Craig; Porro, Gian; O' Connor, Patrick; Waldoch, Connor

2016-09-13

This deck was presented for the 2016 Annual Technology Baseline Webinar. The presentation describes the Annual Technology Baseline, which is a compilation of current and future cost and performance data for electricity generation technologies.

Associations between baseline allergens and polysensitization

DEFF Research Database (Denmark)

Carlsen, B.C.; Menne, T.; Johansen, J.D.

2008-01-01

Background: Identification of patients at risk of developing polysensitization is not possible at present. An association between weak sensitizers and polysensitization has been hypothesized. Objectives: To examine associations of 21 allergens in the European baseline series to polysensitization....... Patients/Methods: From a database-based study with 14 998 patients patch tested with the European baseline series between 1985 and 2005, a group of 759 (5.1%) patients were polysensitized. Odds ratios were calculated to determine the relative contribution of each allergen to polysensitization. Results...... denominator for the association between the allergens and the polysensitization was apparent, and any association, whether positive or negative, was relatively low. Based on these results, sensitization to specific baseline allergens cannot be used as risk indicators for polysensitization Udgivelsesdato: 2008...

Associations between baseline allergens and polysensitization

DEFF Research Database (Denmark)

Carlsen, Berit Christina; Menné, Torkil; Johansen, Jeanne Duus

2008-01-01

BACKGROUND: Identification of patients at risk of developing polysensitization is not possible at present. An association between weak sensitizers and polysensitization has been hypothesized. OBJECTIVES: To examine associations of 21 allergens in the European baseline series to polysensitization....... PATIENTS/METHODS: From a database-based study with 14 998 patients patch tested with the European baseline series between 1985 and 2005, a group of 759 (5.1%) patients were polysensitized. Odds ratios were calculated to determine the relative contribution of each allergen to polysensitization. RESULTS...... denominator for the association between the allergens and the polysensitization was apparent, and any association, whether positive or negative, was relatively low. Based on these results, sensitization to specific baseline allergens cannot be used as risk indicators for polysensitization....

TWRS technical baseline database manager definition document

International Nuclear Information System (INIS)

Acree, C.D.

1997-01-01

This document serves as a guide for using the TWRS Technical Baseline Database Management Systems Engineering (SE) support tool in performing SE activities for the Tank Waste Remediation System (TWRS). This document will provide a consistent interpretation of the relationships between the TWRS Technical Baseline Database Management software and the present TWRS SE practices. The Database Manager currently utilized is the RDD-1000 System manufactured by the Ascent Logic Corporation. In other documents, the term RDD-1000 may be used interchangeably with TWRS Technical Baseline Database Manager

Business-as-Unusual: Existing policies in energy model baselines

International Nuclear Information System (INIS)

Strachan, Neil

2011-01-01

Baselines are generally accepted as a key input assumption in long-term energy modelling, but energy models have traditionally been poor on identifying baselines assumptions. Notably, transparency on the current policy content of model baselines is now especially critical as long-term climate mitigation policies have been underway for a number of years. This paper argues that the range of existing energy and emissions policies are an integral part of any long-term baseline, and hence already represent a 'with-policy' baseline, termed here a Business-as-Unusual (BAuU). Crucially, existing energy policies are not a sunk effort; as impacts of existing policy initiatives are targeted at future years, they may be revised through iterative policy making, and their quantitative effectiveness requires ex-post verification. To assess the long-term role of existing policies in energy modelling, currently identified UK policies are explicitly stripped out of the UK MARKAL Elastic Demand (MED) optimisation energy system model, to generate a BAuU (with-policy) and a REF (without policy) baseline. In terms of long-term mitigation costs, policy-baseline assumptions are comparable to another key exogenous modelling assumption - that of global fossil fuel prices. Therefore, best practice in energy modelling would be to have both a no-policy reference baseline, and a current policy reference baseline (BAuU). At a minimum, energy modelling studies should have a transparent assessment of the current policy contained within the baseline. Clearly identifying and comparing policy-baseline assumptions are required for cost effective and objective policy making, otherwise energy models will underestimate the true cost of long-term emissions reductions.

Pakistan, Sindh Province - Baseline Indicators System : Baseline Procurement Performance Assessment Report

OpenAIRE

World Bank

2009-01-01

This document provides an assessment of the public procurement system in Sindh province using the baseline indicators system developed by the Development Assistance Committee of the Organization for Economic Cooperation and Development (OECD-DAC). This assessment, interviews and discussions were held with stakeholders from the public and private sectors as well as civil society. Developing...

Life Support Baseline Values and Assumptions Document

Science.gov (United States)

Anderson, Molly S.; Ewert, Michael K.; Keener, John F.

2018-01-01

The Baseline Values and Assumptions Document (BVAD) provides analysts, modelers, and other life support researchers with a common set of values and assumptions which can be used as a baseline in their studies. This baseline, in turn, provides a common point of origin from which many studies in the community may depart, making research results easier to compare and providing researchers with reasonable values to assume for areas outside their experience. This document identifies many specific physical quantities that define life support systems, serving as a general reference for spacecraft life support system technology developers.

76 FR 24798 - Airworthiness Directives; Rolls-Royce plc (RR) RB211-Trent 875-17, RB211-Trent 877-17, RB211...

Science.gov (United States)

2011-05-03

... Bulletin SB 72-D672--Introduction of Laser Shock Peening (LSP)) and also a part life upgrade to the... SB 72-D672--Introduction of Laser Shock Peening (LSP)) and also a part life upgrade to the retention...-applying dry film lubricant (DFL) to the fan blades after inspection, either Aircraft Maintenance Manual...

FAQs about Baseline Testing among Young Athletes

Science.gov (United States)

... a similar exam conducted by a health care professional during the season if an athlete has a suspected concussion. Baseline testing generally takes place during the pre-season—ideally prior to the first practice. It is important to note that some baseline ...

75 FR 74706 - Notice of Baseline Filings

Science.gov (United States)

2010-12-01

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Notice of Baseline Filings November 24, 2010. Centana Intrastate Pipeline, LLC. Docket No. PR10-84-001. Centana Intrastate Pipeline, LLC... applicants listed above submitted a revised baseline filing of their Statement of Operating Conditions for...

Geochemical baseline studies of soil in Finland

Science.gov (United States)

Pihlaja, Jouni

2017-04-01

The soil element concentrations regionally vary a lot in Finland. Mostly this is caused by the different bedrock types, which are reflected in the soil qualities. Geological Survey of Finland (GTK) is carrying out geochemical baseline studies in Finland. In the previous phase, the research is focusing on urban areas and mine environments. The information can, for example, be used to determine the need for soil remediation, to assess environmental impacts or to measure the natural state of soil in industrial areas or mine districts. The field work is done by taking soil samples, typically at depth between 0-10 cm. Sampling sites are chosen to represent the most vulnerable areas when thinking of human impacts by possible toxic soil element contents: playgrounds, day-care centers, schools, parks and residential areas. In the mine districts the samples are taken from the areas locating outside the airborne dust effected areas. Element contents of the soil samples are then analyzed with ICP-AES and ICP-MS, Hg with CV-AAS. The results of the geochemical baseline studies are published in the Finnish national geochemical baseline database (TAPIR). The geochemical baseline map service is free for all users via internet browser. Through this map service it is possible to calculate regional soil baseline values using geochemical data stored in the map service database. Baseline data for 17 elements in total is provided in the map service and it can be viewed on the GTK's web pages (http://gtkdata.gtk.fi/Tapir/indexEN.html).

Intrafractional baseline drift during free breathing breast cancer radiation therapy.

Science.gov (United States)

Jensen, Christer Andre; Acosta Roa, Ana María; Lund, Jo-Åsmund; Frengen, Jomar

2017-06-01

Intrafraction motion in breast cancer radiation therapy (BCRT) has not yet been thoroughly described in the literature. It has been observed that baseline drift occurs as part of the intrafraction motion. This study aims to measure baseline drift and its incidence in free-breathing BCRT patients using an in-house developed laser system for tracking the position of the sternum. Baseline drift was monitored in 20 right-sided breast cancer patients receiving free breathing 3D-conformal RT by using an in-house developed laser system which measures one-dimensional distance in the AP direction. A total of 357 patient respiratory traces from treatment sessions were logged and analysed. Baseline drift was compared to patient positioning error measured from in-field portal imaging. The mean overall baseline drift at end of treatment sessions was -1.3 mm for the patient population. Relatively small baseline drift was observed during the first fraction; however it was clearly detected already at the second fraction. Over 90% of the baseline drift occurs during the first 3 min of each treatment session. The baseline drift rate for the population was -0.5 ± 0.2 mm/min in the posterior direction the first minute after localization. Only 4% of the treatment sessions had a 5 mm or larger baseline drift at 5 min, all towards the posterior direction. Mean baseline drift in the posterior direction in free breathing BCRT was observed in 18 of 20 patients over all treatment sessions. This study shows that there is a substantial baseline drift in free breathing BCRT patients. No clear baseline drift was observed during the first treatment session; however, baseline drift was markedly present at the rest of the sessions. Intrafraction motion due to baseline drift should be accounted for in margin calculations.

Extracting Baseline Electricity Usage Using Gradient Tree Boosting

Energy Technology Data Exchange (ETDEWEB)

Kim, Taehoon [Ulsan Nat. Inst. of Sci. & Tech., Ulsan (South Korea); Lee, Dongeun [Ulsan Nat. Inst. of Sci. & Tech., Ulsan (South Korea); Choi, Jaesik [Ulsan Nat. Inst. of Sci. & Tech., Ulsan (South Korea); Spurlock, Anna [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sim, Alex [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Todd, Annika [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wu, Kesheng [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-05-05

To understand how specific interventions affect a process observed over time, we need to control for the other factors that influence outcomes. Such a model that captures all factors other than the one of interest is generally known as a baseline. In our study of how different pricing schemes affect residential electricity consumption, the baseline would need to capture the impact of outdoor temperature along with many other factors. In this work, we examine a number of different data mining techniques and demonstrate Gradient Tree Boosting (GTB) to be an effective method to build the baseline. We train GTB on data prior to the introduction of new pricing schemes, and apply the known temperature following the introduction of new pricing schemes to predict electricity usage with the expected temperature correction. Our experiments and analyses show that the baseline models generated by GTB capture the core characteristics over the two years with the new pricing schemes. In contrast to the majority of regression based techniques which fail to capture the lag between the peak of daily temperature and the peak of electricity usage, the GTB generated baselines are able to correctly capture the delay between the temperature peak and the electricity peak. Furthermore, subtracting this temperature-adjusted baseline from the observed electricity usage, we find that the resulting values are more amenable to interpretation, which demonstrates that the temperature-adjusted baseline is indeed effective.

75 FR 57268 - Notice of Baseline Filings

Science.gov (United States)

2010-09-20

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR10-103-000; Docket No. PR10-104-000; Docket No. PR10-105- 000 (Not Consolidated)] Notice of Baseline Filings September 13..., 2010, and September 10, 2010, respectively the applicants listed above submitted their baseline filing...

75 FR 65010 - Notice of Baseline Filings

Science.gov (United States)

2010-10-21

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR11-1-000; Docket No. PR11-2-000; Docket No. PR11-3-000] Notice of Baseline Filings October 14, 2010. Cranberry Pipeline Docket..., 2010, respectively the applicants listed above submitted their baseline filing of its Statement of...

THE 2014 ALMA LONG BASELINE CAMPAIGN: AN OVERVIEW

Energy Technology Data Exchange (ETDEWEB)

Partnership, ALMA [Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom); Fomalont, E. B.; Vlahakis, C.; Corder, S.; Remijan, A.; Barkats, D.; Dent, W. R. F.; Phillips, N.; Cox, P.; Hales, A. S. [Joint ALMA Observatory, Alonso de Córdova 3107, Vitacura, Santiago (Chile); Lucas, R. [Institut de Planétologie et d’Astrophysique de Grenoble (UMR 5274), BP 53, F-38041 Grenoble Cedex 9 (France); Hunter, T. R.; Brogan, C. L.; Amestica, R.; Cotton, W. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Asaki, Y. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Matsushita, S. [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China); Hills, R. E. [Astrophysics Group, Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Richards, A. M. S. [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Broguiere, D., E-mail: efomalon@nrao.edu [Institut de Radioastronomie Millime´trique (IRAM), 300 rue de la Piscine, Domaine Universitaire, F-38406 Saint Martin d’Hères (France); and others

2015-07-20

A major goal of the Atacama Large Millimeter/submillimeter Array (ALMA) is to make accurate images with resolutions of tens of milliarcseconds, which at submillimeter (submm) wavelengths requires baselines up to ∼15 km. To develop and test this capability, a Long Baseline Campaign (LBC) was carried out from 2014 September to late November, culminating in end-to-end observations, calibrations, and imaging of selected Science Verification (SV) targets. This paper presents an overview of the campaign and its main results, including an investigation of the short-term coherence properties and systematic phase errors over the long baselines at the ALMA site, a summary of the SV targets and observations, and recommendations for science observing strategies at long baselines. Deep ALMA images of the quasar 3C 138 at 97 and 241 GHz are also compared to VLA 43 GHz results, demonstrating an agreement at a level of a few percent. As a result of the extensive program of LBC testing, the highly successful SV imaging at long baselines achieved angular resolutions as fine as 19 mas at ∼350 GHz. Observing with ALMA on baselines of up to 15 km is now possible, and opens up new parameter space for submm astronomy.

THE 2014 ALMA LONG BASELINE CAMPAIGN: AN OVERVIEW

International Nuclear Information System (INIS)

Partnership, ALMA; Fomalont, E. B.; Vlahakis, C.; Corder, S.; Remijan, A.; Barkats, D.; Dent, W. R. F.; Phillips, N.; Cox, P.; Hales, A. S.; Lucas, R.; Hunter, T. R.; Brogan, C. L.; Amestica, R.; Cotton, W.; Asaki, Y.; Matsushita, S.; Hills, R. E.; Richards, A. M. S.; Broguiere, D.

2015-01-01

A major goal of the Atacama Large Millimeter/submillimeter Array (ALMA) is to make accurate images with resolutions of tens of milliarcseconds, which at submillimeter (submm) wavelengths requires baselines up to ∼15 km. To develop and test this capability, a Long Baseline Campaign (LBC) was carried out from 2014 September to late November, culminating in end-to-end observations, calibrations, and imaging of selected Science Verification (SV) targets. This paper presents an overview of the campaign and its main results, including an investigation of the short-term coherence properties and systematic phase errors over the long baselines at the ALMA site, a summary of the SV targets and observations, and recommendations for science observing strategies at long baselines. Deep ALMA images of the quasar 3C 138 at 97 and 241 GHz are also compared to VLA 43 GHz results, demonstrating an agreement at a level of a few percent. As a result of the extensive program of LBC testing, the highly successful SV imaging at long baselines achieved angular resolutions as fine as 19 mas at ∼350 GHz. Observing with ALMA on baselines of up to 15 km is now possible, and opens up new parameter space for submm astronomy

76 FR 8725 - Notice of Baseline Filings

Science.gov (United States)

2011-02-15

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Notice of Baseline Filings Enstor Grama Ridge Storage and Docket No. PR10-97-002. Transportation, L.L.C.. EasTrans, LLC Docket No. PR10-30-001... revised baseline filing of their Statement of Operating Conditions for services provided under section 311...

76 FR 5797 - Notice of Baseline Filings

Science.gov (United States)

2011-02-02

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR10-114-001; Docket No. PR10-129-001; Docket No. PR10-131- 001; Docket No. PR10-68-002 Not Consolidated] Notice of Baseline... applicants listed above submitted a revised baseline filing of their Statement of Operating Conditions for...

Office of Geologic Repositories program baseline procedures notebook (OGR/B-1)

International Nuclear Information System (INIS)

1986-06-01

Baseline management is typically applied to aid in the internal control of a program by providing consistent programmatic direction, control, and surveillance to an evolving system development. This fundamental concept of internal program control involves the establishment of a baseline to serve as a point of departure for consistent technical program coordination and to control subsequent changes from that baseline. The existence of a program-authorized baseline ensures that all participants are working to the same ground rules. Baseline management also ensures that, once the baseline is defined, changes are assessed and approved by a process which ensures adequate consideration of overall program impact. Baseline management also includes the consideration of examptions from the baseline. The process of baseline management continues through all the phases of an evolving system development program. As the Program proceeds, there will be a progressive increase in the data contained in the baseline documentation. Baseline management has been selected as a management technique to aid in the internal control of the Office of Geologic Repositories (OGR) program. Specifically, an OGR Program Baseline, including technical and programmatic requirements, is used for program control of the four Mined Geologic Disposal System field projects, i.e., Basalt Waste Isolation Project, Nevada Nuclear Waste Storage Investigation, Salt Repository Project and Crystalline Repository Project. This OGR Program Baseline Procedures Notebook provides a description of the baseline mwanagement concept, establishes the OGR Program baseline itself, and provides procedures to be followed for controlling changes to that baseline. The notebook has a controlled distribution and will be updated as required

Accelerated Best Basis Inventory Baselining Task

International Nuclear Information System (INIS)

SASAKI, L.M.

2001-01-01

The baselining effort was recently proposed to bring the Best-Basis Inventory (BBI) and Question No.8 of the Tank Interpretive Report (TIR) for all 177 tanks to the current standards and protocols and to prepare a TIR Question No.8 if one is not already available. This plan outlines the objectives and methodology of the accelerated BBI baselining task. BBI baselining meetings held during December 2000 resulted in a revised BBI methodology and an initial set of BBI creation rules to be used in the baselining effort. The objectives of the BBI baselining effort are to: (1) Provide inventories that are consistent with the revised BBI methodology and new BBI creation rules. (2) Split the total tank waste in each tank into six waste phases, as appropriate (Supernatant, saltcake solids, saltcake liquid, sludge solids, sludge liquid, and retained gas). In some tanks, the solids and liquid portions of the sludge and/or saltcake may be combined into a single sludge or saltcake phase. (3) Identify sampling events that are to be used for calculating the BBIs. (4) Update waste volumes for subsequent reconciliation with the Hanlon (2001) waste tank summary. (5) Implement new waste type templates. (6) Include any sample data that might have been unintentionally omitted in the previous BBI and remove any sample data that should not have been included. Sample data to be used in the BBI must be available on TWINS. (7) Ensure that an inventory value for each standard BBI analyte is provided for each waste component. Sample based inventories for supplemental BBI analytes will be included when available. (8) Provide new means and confidence interval reports if one is not already available and include uncertainties in reporting inventory values

75 FR 70732 - Notice of Baseline Filings

Science.gov (United States)

2010-11-18

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR11-71-000; Docket No. PR11-72-000; Docket No. PR11-73- 000] Notice of Baseline Filings November 10, 2010. Docket No. PR11-71-000..., 2010, the applicants listed above submitted their baseline filing of their Statement of Operating...

MALDI-TOF Baseline Drift Removal Using Stochastic Bernstein Approximation

Directory of Open Access Journals (Sweden)

Howard Daniel

2006-01-01

Full Text Available Stochastic Bernstein (SB approximation can tackle the problem of baseline drift correction of instrumentation data. This is demonstrated for spectral data: matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF data. Two SB schemes for removing the baseline drift are presented: iterative and direct. Following an explanation of the origin of the MALDI-TOF baseline drift that sheds light on the inherent difficulty of its removal by chemical means, SB baseline drift removal is illustrated for both proteomics and genomics MALDI-TOF data sets. SB is an elegant signal processing method to obtain a numerically straightforward baseline shift removal method as it includes a free parameter that can be optimized for different baseline drift removal applications. Therefore, research that determines putative biomarkers from the spectral data might benefit from a sensitivity analysis to the underlying spectral measurement that is made possible by varying the SB free parameter. This can be manually tuned (for constant or tuned with evolutionary computation (for .

Physics Potential of Long-Baseline Experiments

Directory of Open Access Journals (Sweden)

Sanjib Kumar Agarwalla

2014-01-01

Full Text Available The discovery of neutrino mixing and oscillations over the past decade provides firm evidence for new physics beyond the Standard Model. Recently, θ13 has been determined to be moderately large, quite close to its previous upper bound. This represents a significant milestone in establishing the three-flavor oscillation picture of neutrinos. It has opened up exciting prospects for current and future long-baseline neutrino oscillation experiments towards addressing the remaining fundamental questions, in particular the type of the neutrino mass hierarchy and the possible presence of a CP-violating phase. Another recent and crucial development is the indication of non-maximal 2-3 mixing angle, causing the octant ambiguity of θ23. In this paper, I will review the phenomenology of long-baseline neutrino oscillations with a special emphasis on sub-leading three-flavor effects, which will play a crucial role in resolving these unknowns. First, I will give a brief description of neutrino oscillation phenomenon. Then, I will discuss our present global understanding of the neutrino mass-mixing parameters and will identify the major unknowns in this sector. After that, I will present the physics reach of current generation long-baseline experiments. Finally, I will conclude with a discussion on the physics capabilities of accelerator-driven possible future long-baseline precision oscillation facilities.

Precise baseline determination for the TanDEM-X mission

Science.gov (United States)

Koenig, Rolf; Moon, Yongjin; Neumayer, Hans; Wermuth, Martin; Montenbruck, Oliver; Jäggi, Adrian

The TanDEM-X mission will strive for generating a global precise Digital Elevation Model (DEM) by way of bi-static SAR in a close formation of the TerraSAR-X satellite, already launched on June 15, 2007, and the TanDEM-X satellite to be launched in May 2010. Both satellites carry the Tracking, Occultation and Ranging (TOR) payload supplied by the GFZ German Research Centre for Geosciences. The TOR consists of a high-precision dual-frequency GPS receiver, called Integrated GPS Occultation Receiver (IGOR), and a Laser retro-reflector (LRR) for precise orbit determination (POD) and atmospheric sounding. The IGOR is of vital importance for the TanDEM-X mission objectives as the millimeter level determination of the baseline or distance between the two spacecrafts is needed to derive meter level accurate DEMs. Within the TanDEM-X ground segment GFZ is responsible for the operational provision of precise baselines. For this GFZ uses two software chains, first its Earth Parameter and Orbit System (EPOS) software and second the BERNESE software, for backup purposes and quality control. In a concerted effort also the German Aerospace Center (DLR) generates precise baselines independently with a dedicated Kalman filter approach realized in its FRNS software. By the example of GRACE the generation of baselines with millimeter accuracy from on-board GPS data can be validated directly by way of comparing them to the intersatellite K-band range measurements. The K-band ranges are accurate down to the micrometer-level and therefore may be considered as truth. Both TanDEM-X baseline providers are able to generate GRACE baselines with sub-millimeter accuracy. By merging the independent baselines by GFZ and DLR, the accuracy can even be increased. The K-band validation however covers solely the along-track component as the K-band data measure just the distance between the two GRACE satellites. In addition they inhibit an un-known bias which must be modelled in the comparison, so the

Baseline Response Levels Are a Nuisance in Infant Contingency Learning

Science.gov (United States)

Millar, W. S.; Weir, Catherine

2015-01-01

The impact of differences in level of baseline responding on contingency learning in the first year was examined by considering the response acquisition of infants classified into baseline response quartiles. Whereas the three lower baseline groups showed the predicted increment in responding to a contingency, the highest baseline responders did…

IPCC Socio-Economic Baseline Dataset

Data.gov (United States)

National Aeronautics and Space Administration — The Intergovernmental Panel on Climate Change (IPCC) Socio-Economic Baseline Dataset consists of population, human development, economic, water resources, land...

Baseline methodologies for clean development mechanism projects

Energy Technology Data Exchange (ETDEWEB)

Lee, M.K. (ed.); Shrestha, R.M.; Sharma, S.; Timilsina, G.R.; Kumar, S.

2005-11-15

The Kyoto Protocol and the Clean Development Mechanism (CDM) came into force on 16th February 2005 with its ratification by Russia. The increasing momentum of this process is reflected in more than 100 projects having been submitted to the CDM Executive Board (CDM-EB) for approval of the baselines and monitoring methodologies, which is the first step in developing and implementing CDM projects. A CDM project should result in a net decrease of GHG emissions below any level that would have resulted from other activities implemented in the absence of that CDM project. The 'baseline' defines the GHG emissions of activities that would have been implemented in the absence of a CDM project. The baseline methodology is the process/algorithm for establishing that baseline. The baseline, along with the baseline methodology, are thus the most critical element of any CDM project towards meeting the important criteria of CDM, which are that a CDM should result in 'real, measurable, and long term benefits related to the mitigation of climate change'. This guidebook is produced within the frame work of the United Nations Environment Programme (UNEP) facilitated 'Capacity Development for the Clean Development Mechanism (CD4CDM)' Project. This document is published as part of the projects effort to develop guidebooks that cover important issues such as project finance, sustainability impacts, legal framework and institutional framework. These materials are aimed to help stakeholders better understand the CDM and are believed to eventually contribute to maximize the effect of the CDM in achieving the ultimate goal of UNFCCC and its Kyoto Protocol. This Guidebook should be read in conjunction with the information provided in the two other guidebooks entitled, 'Clean Development Mechanism: Introduction to the CDM' and 'CDM Information and Guidebook' developed under the CD4CDM project. (BA)

Baseline methodologies for clean development mechanism projects

International Nuclear Information System (INIS)

Lee, M.K.; Shrestha, R.M.; Sharma, S.; Timilsina, G.R.; Kumar, S.

2005-11-01

The Kyoto Protocol and the Clean Development Mechanism (CDM) came into force on 16th February 2005 with its ratification by Russia. The increasing momentum of this process is reflected in more than 100 projects having been submitted to the CDM Executive Board (CDM-EB) for approval of the baselines and monitoring methodologies, which is the first step in developing and implementing CDM projects. A CDM project should result in a net decrease of GHG emissions below any level that would have resulted from other activities implemented in the absence of that CDM project. The 'baseline' defines the GHG emissions of activities that would have been implemented in the absence of a CDM project. The baseline methodology is the process/algorithm for establishing that baseline. The baseline, along with the baseline methodology, are thus the most critical element of any CDM project towards meeting the important criteria of CDM, which are that a CDM should result in 'real, measurable, and long term benefits related to the mitigation of climate change'. This guidebook is produced within the frame work of the United Nations Environment Programme (UNEP) facilitated 'Capacity Development for the Clean Development Mechanism (CD4CDM)' Project. This document is published as part of the projects effort to develop guidebooks that cover important issues such as project finance, sustainability impacts, legal framework and institutional framework. These materials are aimed to help stakeholders better understand the CDM and are believed to eventually contribute to maximize the effect of the CDM in achieving the ultimate goal of UNFCCC and its Kyoto Protocol. This Guidebook should be read in conjunction with the information provided in the two other guidebooks entitled, 'Clean Development Mechanism: Introduction to the CDM' and 'CDM Information and Guidebook' developed under the CD4CDM project. (BA)

Baseline budgeting for continuous improvement.

Science.gov (United States)

Kilty, G L

1999-05-01

This article is designed to introduce the techniques used to convert traditionally maintained department budgets to baseline budgets. This entails identifying key activities, evaluating for value-added, and implementing continuous improvement opportunities. Baseline Budgeting for Continuous Improvement was created as a result of a newly named company president's request to implement zero-based budgeting. The president was frustrated with the mind-set of the organization, namely, "Next year's budget should be 10 to 15 percent more than this year's spending." Zero-based budgeting was not the answer, but combining the principles of activity-based costing and the Just-in-Time philosophy of eliminating waste and continuous improvement did provide a solution to the problem.

Safe and sensible preprocessing and baseline correction of pupil-size data.

Science.gov (United States)

Mathôt, Sebastiaan; Fabius, Jasper; Van Heusden, Elle; Van der Stigchel, Stefan

2018-02-01

Measurement of pupil size (pupillometry) has recently gained renewed interest from psychologists, but there is little agreement on how pupil-size data is best analyzed. Here we focus on one aspect of pupillometric analyses: baseline correction, i.e., analyzing changes in pupil size relative to a baseline period. Baseline correction is useful in experiments that investigate the effect of some experimental manipulation on pupil size. In such experiments, baseline correction improves statistical power by taking into account random fluctuations in pupil size over time. However, we show that baseline correction can also distort data if unrealistically small pupil sizes are recorded during the baseline period, which can easily occur due to eye blinks, data loss, or other distortions. Divisive baseline correction (corrected pupil size = pupil size/baseline) is affected more strongly by such distortions than subtractive baseline correction (corrected pupil size = pupil size - baseline). We discuss the role of baseline correction as a part of preprocessing of pupillometric data, and make five recommendations: (1) before baseline correction, perform data preprocessing to mark missing and invalid data, but assume that some distortions will remain in the data; (2) use subtractive baseline correction; (3) visually compare your corrected and uncorrected data; (4) be wary of pupil-size effects that emerge faster than the latency of the pupillary response allows (within ±220 ms after the manipulation that induces the effect); and (5) remove trials on which baseline pupil size is unrealistically small (indicative of blinks and other distortions).

Performance Measurement Baseline Change Request

Data.gov (United States)

Social Security Administration — The Performance Measurement Baseline Change Request template is used to document changes to scope, cost, schedule, or operational performance metrics for SSA's Major...

Effect of some types of machining processes on beryllium fatigue strength properties

International Nuclear Information System (INIS)

Armbruster, M.

1977-01-01

The aim of this work, which is sponsored by the French D.G.R.S.T., is to determine a machining process giving both the highest tensile strength and the highest fatigue limit to beryllium parts. A comparison is made of the effects of : mechanical machining, electro discharge machining, electro-chemical machining, electrolytical and chemical polishing, glass shot peening, on the mechanical strength and fatigue limits of samples taken from hot pressed and extruded rods and from cast ingot sheets, either notched or not as required. Complementary examinations are performed principally by fractographic study. The results show that for beryllium, electrochemical machining followed by glass shot peening gives the best results; however mechanical machining with electrolytical polishing followed by glass shot peening are also satisfactory. (author)

An Automated Baseline Correction Method Based on Iterative Morphological Operations.

Science.gov (United States)

Chen, Yunliang; Dai, Liankui

2018-05-01

Raman spectra usually suffer from baseline drift caused by fluorescence or other reasons. Therefore, baseline correction is a necessary and crucial step that must be performed before subsequent processing and analysis of Raman spectra. An automated baseline correction method based on iterative morphological operations is proposed in this work. The method can adaptively determine the structuring element first and then gradually remove the spectral peaks during iteration to get an estimated baseline. Experiments on simulated data and real-world Raman data show that the proposed method is accurate, fast, and flexible for handling different kinds of baselines in various practical situations. The comparison of the proposed method with some state-of-the-art baseline correction methods demonstrates its advantages over the existing methods in terms of accuracy, adaptability, and flexibility. Although only Raman spectra are investigated in this paper, the proposed method is hopefully to be used for the baseline correction of other analytical instrumental signals, such as IR spectra and chromatograms.

Rationing with baselines

DEFF Research Database (Denmark)

Hougaard, Jens Leth; Moreno-Ternero, Juan D.; Østerdal, Lars Peter Raahave

2013-01-01

We introduce a new operator for general rationing problems in which, besides conflicting claims, individual baselines play an important role in the rationing process. The operator builds onto ideas of composition, which are not only frequent in rationing, but also in related problems...... such as bargaining, choice, and queuing. We characterize the operator and show how it preserves some standard axioms in the literature on rationing. We also relate it to recent contributions in such literature....

Mercury baseline levels in Flemish soils (Belgium)

International Nuclear Information System (INIS)

Tack, Filip M.G.; Vanhaesebroeck, Thomas; Verloo, Marc G.; Van Rompaey, Kurt; Ranst, Eric van

2005-01-01

It is important to establish contaminant levels that are normally present in soils to provide baseline data for pollution studies. Mercury is a toxic element of concern. This study was aimed at assessing baseline mercury levels in soils in Flanders. In a previous study, mercury contents in soils in Oost-Vlaanderen were found to be significantly above levels reported elsewhere. For the current study, observations were extended over two more provinces, West-Vlaanderen and Antwerpen. Ranges of soil Hg contents were distinctly higher in the province Oost-Vlaanderen (interquartile range from 0.09 to 0.43 mg/kg) than in the other provinces (interquartile ranges from 0.7 to 0.13 and 0.7 to 0.15 mg/kg for West-Vlaanderen and Antwerpen, respectively). The standard threshold method was applied to separate soils containing baseline levels of Hg from the data. Baseline concentrations for Hg were characterised by a median of 0.10 mg Hg/kg dry soil, an interquartile range from 0.07 to 0.14 mg/kg and a 90% percentile value of 0.30 mg/kg. The influence of soil properties such as clay and organic carbon contents, and pH on baseline Hg concentrations was not important. Maps of the spatial distribution of Hg levels showed that the province Oost-Vlaanderen exhibited zones with systematically higher Hg soil contents. This may be related to the former presence of many small-scale industries employing mercury in that region. - Increased mercury levels may reflect human activity

Tank waste remediation system technical baseline summary description

International Nuclear Information System (INIS)

Raymond, R.E.

1998-01-01

This document is one of the tools used to develop and control the mission work as depicted in the included figure. This Technical Baseline Summary Description document is the top-level tool for management of the Technical Baseline for waste storage operations

Poly[[tetrakis(μ2-pyrazine N,N′-dioxide-κ2O:O′erbium(III] tris(perchlorate

Directory of Open Access Journals (Sweden)

James D. Buchner

2010-09-01

Full Text Available The title three-dimensional coordination network, {[Er(C4H4N2O24](ClO43}n, is isostructural to that of other lanthanides. The Er+3 cation lies on a fourfold roto-inversion axis. It is coordinated in a distorted square-antiprismatic fashion by eight O atoms from bridging pyrazine N,N′-dioxide ligands. There are two unique pyrazine N,N′-dioxide ligands. One ring is located around an inversion center, and there is a a twofold rotation axis at the center of the other ring. There are also two unique perchlorate anions. One is centered on a twofold rotation axis and the other on a fourfold roto-inversion axis. The perchlorate anions are located in channels that run perpendicular to (001 and (110 and interact with the coordination network through C—H...O hydrogen bonds.

Simultaneous characterization of rotational and translational diffusion of optically anisotropic particles by optical microscopy

International Nuclear Information System (INIS)

Giavazzi, Fabio; Cerbino, Roberto; Haro-Pérez, Catalina

2016-01-01

We probe the roto-translational Brownian motion of optically anisotropic particles suspended in water with a simple and straightforward optical microscopy experiment that does not require positional or rotational particle tracking. We acquire a movie of the suspension placed between two polarizing elements and we extract the translational diffusion coefficient D T and the rotational diffusion coefficient D R from the analysis of the temporal correlation properties of the spatial Fourier modes of the intensity fluctuations in the movie. Our method is successfully tested with a dilute suspension of birefringent spherical colloidal particles obtained by polymerizing an emulsion of droplets of liquid crystal in a nematic phase, whose roto-translational dynamics is found to be well described by theory. The simplicity of our approach makes our method a viable alternative to particle tracking and depolarized dynamic light scattering. (paper)

Carbon tetrachloride ERA soil-gas baseline monitoring

International Nuclear Information System (INIS)

Fancher, J.D.

1994-01-01

From December 1991 through December 1993, Westinghouse Hanford Company performed routine baseline monitoring of selected wells ad soil-gas points twice weekly in the 200 West Area of the Hanford Site. This work supported the carbon Tetrachloride Expedited Response Action (ERA) and provided a solid baseline of volatile organic compound (VOC) concentrations in wells and in the subsurface at the ERA site. As site remediation continues, comparisons to this baseline can be one means of measuring the success of carbon tetrachloride vapor extraction. This report contains observations of the patterns and trends associated with data obtained during soil-gas monitoring at the 200 West Area: Monitoring performed since late 1991 includes monitoring soil-gas probes ad wellheads for volatile organic compounds (VOCs). This report reflects monitoring data collected from December 1991 through December 1993

324 Building Baseline Radiological Characterization

Energy Technology Data Exchange (ETDEWEB)

R.J. Reeder, J.C. Cooper

2010-06-24

This report documents the analysis of radiological data collected as part of the characterization study performed in 1998. The study was performed to create a baseline of the radiological conditions in the 324 Building.

Digital baseline estimation method for multi-channel pulse height analyzing

International Nuclear Information System (INIS)

Xiao Wuyun; Wei Yixiang; Ai Xianyun

2005-01-01

The basic features of digital baseline estimation for multi-channel pulse height analysis are introduced. The weight-function of minimum-noise baseline filter is deduced with functional variational calculus. The frequency response of this filter is also deduced with Fourier transformation, and the influence of parameters on amplitude frequency response characteristics is discussed. With MATLAB software, the noise voltage signal from the charge sensitive preamplifier is simulated, and the processing effect of minimum-noise digital baseline estimation is verified. According to the results of this research, digital baseline estimation method can estimate baseline optimally, and it is very suitable to be used in digital multi-channel pulse height analysis. (authors)

Characterisation of foreign object damage (FOD) and early fatigue crack growth in laser shock peened Ti-6Al-4V aerofoil specimens

Energy Technology Data Exchange (ETDEWEB)

Spanrad, S. [Mechanical Behaviour of Materials Laboratory, Department of Mechanical and Design Engineering, University of Portsmouth (United Kingdom); Tong, J., E-mail: jie.tong@port.ac.uk [Mechanical Behaviour of Materials Laboratory, Department of Mechanical and Design Engineering, University of Portsmouth (United Kingdom)

2011-02-25

Research highlights: {yields} A study of deformation in a generic LSPed aerofoil specimen subjected to high speed head-on and 45 deg. impacts, and subsequently fatigue loading. {yields} Characterisation of damage features considering geometry of the projectile, impact angle and impact velocity. {yields} Onset and early crack growth due to FOD in LSPed samples compared to those without LSP subjected to cubical impacts under simulated service loading conditions. - Abstract: Foreign object damage (FOD) has been identified as one of the primary life limiting factors for fan and compressor blades, with the leading edge of aerofoils particularly susceptible to such damage. In this study, a generic aerofoil specimen of Ti-6Al-4V alloy was used. The specimens were treated by laser shock peening (LSP) to generate compressive residual stresses in the leading edge region prior to impact. FOD was simulated by firing a cubical projectile at the leading edge using a laboratory gas gun at 200 m/s, head-on; and at 250 m/s, at an angle of 45 deg. The specimens were then subjected to 4-point bend fatigue testing under high cycle (HCF), low cycle (LCF) and combined LCF and HCF loading conditions. Scanning electron microscopy (SEM) was used to characterise the damage features due to FOD. Crack initiation and early crack growth due to FOD and subsequent fatigue growth were examined in detail. The results were compared between the two impact conditions; and with those from samples without LSP treatment as well as those impacted with spherical projectiles. The results seem to suggest that LSP has improved the crack growth resistance post FOD. Delayed onset of crack initiation was observed in LSPed samples compared to those without LSP under similar loading conditions. Damage features depend on the geometry of the projectile, the impact angle as well as the impact velocity.

First Grade Baseline Evaluation

Science.gov (United States)

Center for Innovation in Assessment (NJ1), 2013

2013-01-01

The First Grade Baseline Evaluation is an optional tool that can be used at the beginning of the school year to help teachers get to know the reading and language skills of each student. The evaluation is composed of seven screenings. Teachers may use the entire evaluation or choose to use those individual screenings that they find most beneficial…

Esophageal acid exposure decreases intraluminal baseline impedance levels

NARCIS (Netherlands)

Kessing, Boudewijn F.; Bredenoord, Albert J.; Weijenborg, Pim W.; Hemmink, Gerrit J. M.; Loots, Clara M.; Smout, A. J. P. M.

2011-01-01

Intraluminal baseline impedance levels are determined by the conductivity of the esophageal wall and can be decreased in gastroesophageal reflux disease (GERD) patients. The aim of this study was to investigate the baseline impedance in GERD patients, on and off proton pump inhibitor (PPI), and in

Measuring cognitive change with ImPACT: the aggregate baseline approach.

Science.gov (United States)

Bruce, Jared M; Echemendia, Ruben J; Meeuwisse, Willem; Hutchison, Michael G; Aubry, Mark; Comper, Paul

2017-11-01

The Immediate Post-Concussion Assessment and Cognitive Test (ImPACT) is commonly used to assess baseline and post-injury cognition among athletes in North America. Despite this, several studies have questioned the reliability of ImPACT when given at intervals employed in clinical practice. Poor test-retest reliability reduces test sensitivity to cognitive decline, increasing the likelihood that concussed athletes will be returned to play prematurely. We recently showed that the reliability of ImPACT can be increased when using a new composite structure and the aggregate of two baselines to predict subsequent performance. The purpose of the present study was to confirm our previous findings and determine whether the addition of a third baseline would further increase the test-retest reliability of ImPACT. Data from 97 English speaking professional hockey players who had received at least 4 ImPACT baseline evaluations were extracted from a National Hockey League Concussion Program database. Linear regression was used to determine whether each of the first three testing sessions accounted for unique variance in the fourth testing session. Results confirmed that the aggregate baseline approach improves the psychometric properties of ImPACT, with most indices demonstrating adequate or better test-retest reliability for clinical use. The aggregate baseline approach provides a modest clinical benefit when recent baselines are available - and a more substantial benefit when compared to approaches that obtain baseline measures only once during the course of a multi-year playing career. Pending confirmation in diverse samples, neuropsychologists are encouraged to use the aggregate baseline approach to best quantify cognitive change following sports concussion.

Study on the calibration and optimization of double theodolites baseline

Science.gov (United States)

Ma, Jing-yi; Ni, Jin-ping; Wu, Zhi-chao

2018-01-01

For the double theodolites measurement system baseline as the benchmark of the scale of the measurement system and affect the accuracy of the system, this paper puts forward a method for calibration and optimization of the double theodolites baseline. Using double theodolites to measure the known length of the reference ruler, and then reverse the baseline formula. Based on the error propagation law, the analyses show that the baseline error function is an important index to measure the accuracy of the system, and the reference ruler position, posture and so on have an impact on the baseline error. The optimization model is established and the baseline error function is used as the objective function, and optimizes the position and posture of the reference ruler. The simulation results show that the height of the reference ruler has no effect on the baseline error; the posture is not uniform; when the reference ruler is placed at x=500mm and y=1000mm in the measurement space, the baseline error is the smallest. The experimental results show that the experimental results are consistent with the theoretical analyses in the measurement space. In this paper, based on the study of the placement of the reference ruler, for improving the accuracy of the double theodolites measurement system has a reference value.

STATUS OF THE US LONG BASELINE NEUTRINO EXPERIMENT STUDY.

Energy Technology Data Exchange (ETDEWEB)

BISHAI,M.

2006-09-21

The US Long Baseline Neutrino Experiment Study was commissioned jointly by Brookhaven National Laboratory and Fermi National Accelerator Laboratory to investigate the potential for future U.S. based long baseline neutrino oscillation experiments beyond the currently planned program. The Study focused on MW class convention at neutrino beams that can be produced at Fermilab or BNL. The experimental baselines are based on two possible detector locations: (1) off-axis to the existing Fermilab NuMI beamline at baselines of 700 to 810 km and (2) NSF's proposed future Deep Underground Science and Engineering Laboratory (DUSEL) at baselines greater than 1000 km. Two detector technologies are considered: a megaton class Water Cherenkov detector deployed deep underground at a DUSEL site, or a 100kT Liquid Argon Time-Projection Chamber (TPC) deployed on the surface at any of the proposed sites. The physics sensitivities of the proposed experiments are summarized. We find that conventional horn focused wide-band neutrino beam options from Fermilab or BNL aimed at a massive detector with a baseline of > 1000 km have the best sensitivity to CP violation and the neutrino mass hierarchy for values of the mixing angle {theta}{sub 13} down to 2.2{sup o}.

Placental baseline conditions modulate the hyperoxic BOLD-MRI response.

Science.gov (United States)

Sinding, Marianne; Peters, David A; Poulsen, Sofie S; Frøkjær, Jens B; Christiansen, Ole B; Petersen, Astrid; Uldbjerg, Niels; Sørensen, Anne

2018-01-01

Human pregnancies complicated by placental dysfunction may be characterized by a high hyperoxic Blood oxygen level-dependent (BOLD) MRI response. The pathophysiology behind this phenomenon remains to be established. The aim of this study was to evaluate whether it is associated with altered placental baseline conditions, including a lower oxygenation and altered tissue morphology, as estimated by the placental transverse relaxation time (T2*). We included 49 normal pregnancies (controls) and 13 pregnancies complicated by placental dysfunction (cases), defined by a birth weight baseline BOLD)/baseline BOLD) from a dynamic single-echo gradient-recalled echo (GRE) MRI sequence and the absolute ΔT2* (hyperoxic T2*- baseline T2*) from breath-hold multi-echo GRE sequences. In the control group, the relative ΔBOLD response increased during gestation from 5% in gestational week 20 to 20% in week 40. In the case group, the relative ΔBOLD response was significantly higher (mean Z-score 4.94; 95% CI 2.41, 7.47). The absolute ΔT2*, however, did not differ between controls and cases (p = 0.37), whereas the baseline T2* was lower among cases (mean Z-score -3.13; 95% CI -3.94, -2.32). Furthermore, we demonstrated a strong negative linear correlation between the Log 10 ΔBOLD response and the baseline T2* (r = -0.88, p baseline conditions, as the absolute increase in placental oxygenation (ΔT2*) does not differ between groups. Copyright © 2017 Elsevier Ltd. All rights reserved.

Baseline restoration technique based on symmetrical zero-area trapezoidal pulse shaper

Energy Technology Data Exchange (ETDEWEB)

Zeng, Guoqiang, E-mail: 24829500@qq.com [Key Laboratory of Applied Nuclear Techniques in Geosciences Sichuan, Chengdu University of Technology, Chengdu 610059 (China); Yang, Jian, E-mail: 22105653@qq.com [Key Laboratory of Applied Nuclear Techniques in Geosciences Sichuan, Chengdu University of Technology, Chengdu 610059 (China); Hu, Tianyu; Ge, Liangquan [Key Laboratory of Applied Nuclear Techniques in Geosciences Sichuan, Chengdu University of Technology, Chengdu 610059 (China); Ouyang, Xiaoping [Northwest Institute of Nuclear Technology, Xi’an 710024,China (China); Zhang, Qingxian; Gu, Yi [Key Laboratory of Applied Nuclear Techniques in Geosciences Sichuan, Chengdu University of Technology, Chengdu 610059 (China)

2017-06-21

Since the baseline of the unipolar pulse shaper have the direct-current (DC) offset and drift, an additional baseline estimator is need to obtain baseline values in real-time. The bipolar zero-area (BZA) pulse shapers can be used for baseline restoration, but they cannot restrain the baseline drift due to their asymmetrical shape. In this study, three trapezoids are synthesized as a symmetrical zero-area (SZA) shape, which can remove the DC offset and restrain the baseline drift. This baseline restoration technique can be easily implemented in digital pulse processing (DPP) systems base on the recursive algorithm. To strengthen our approach, the iron's characteristic x-ray was detected using a Si-PIN diode detector. Compared with traditional trapezoidal pulse shapers, the SZA trapezoidal pulse shaper improved the energy resolution from 237 eV to 216 eV for the 6.403 keV Kα peak.

A Fully Customized Baseline Removal Framework for Spectroscopic Applications.

Science.gov (United States)

Giguere, Stephen; Boucher, Thomas; Carey, C J; Mahadevan, Sridhar; Dyar, M Darby

2017-07-01

The task of proper baseline or continuum removal is common to nearly all types of spectroscopy. Its goal is to remove any portion of a signal that is irrelevant to features of interest while preserving any predictive information. Despite the importance of baseline removal, median or guessed default parameters are commonly employed, often using commercially available software supplied with instruments. Several published baseline removal algorithms have been shown to be useful for particular spectroscopic applications but their generalizability is ambiguous. The new Custom Baseline Removal (Custom BLR) method presented here generalizes the problem of baseline removal by combining operations from previously proposed methods to synthesize new correction algorithms. It creates novel methods for each technique, application, and training set, discovering new algorithms that maximize the predictive accuracy of the resulting spectroscopic models. In most cases, these learned methods either match or improve on the performance of the best alternative. Examples of these advantages are shown for three different scenarios: quantification of components in near-infrared spectra of corn and laser-induced breakdown spectroscopy data of rocks, and classification/matching of minerals using Raman spectroscopy. Software to implement this optimization is available from the authors. By removing subjectivity from this commonly encountered task, Custom BLR is a significant step toward completely automatic and general baseline removal in spectroscopic and other applications.

High Baseline Postconcussion Symptom Scores and Concussion Outcomes in Athletes.

Science.gov (United States)

Custer, Aimee; Sufrinko, Alicia; Elbin, R J; Covassin, Tracey; Collins, Micky; Kontos, Anthony

2016-02-01

Some healthy athletes report high levels of baseline concussion symptoms, which may be attributable to several factors (eg, illness, personality, somaticizing). However, the role of baseline symptoms in outcomes after sport-related concussion (SRC) has not been empirically examined. To determine if athletes with high symptom scores at baseline performed worse than athletes without baseline symptoms on neurocognitive testing after SRC. Cohort study. High school and collegiate athletic programs. A total of 670 high school and collegiate athletes participated in the study. Participants were divided into groups with either no baseline symptoms (Postconcussion Symptom Scale [PCSS] score = 0, n = 247) or a high level of baseline symptoms (PCSS score > 18 [top 10% of sample], n = 68). Participants were evaluated at baseline and 2 to 7 days after SRC with the Immediate Post-concussion Assessment and Cognitive Test and PCSS. Outcome measures were Immediate Post-concussion Assessment and Cognitive Test composite scores (verbal memory, visual memory, visual motor processing speed, and reaction time) and total symptom score on the PCSS. The groups were compared using repeated-measures analyses of variance with Bonferroni correction to assess interactions between group and time for symptoms and neurocognitive impairment. The no-symptoms group represented 38% of the original sample, whereas the high-symptoms group represented 11% of the sample. The high-symptoms group experienced a larger decline from preinjury to postinjury than the no-symptoms group in verbal (P = .03) and visual memory (P = .05). However, total concussion-symptom scores increased from preinjury to postinjury for the no-symptoms group (P = .001) but remained stable for the high-symptoms group. Reported baseline symptoms may help identify athletes at risk for worse outcomes after SRC. Clinicians should examine baseline symptom levels to better identify patients for earlier referral and treatment for their

Baseline effects on carbon footprints of biofuels: The case of wood

Energy Technology Data Exchange (ETDEWEB)

Johnson, Eric, E-mail: johnsonatlantic@gmail.com [Atlantic Consulting, 8136 Gattikon (Switzerland); Tschudi, Daniel [ETH, Berghaldenstrasse 46, 8800 Thalwil (Switzerland)

2012-11-15

As biofuel usage has boomed over the past decade, so has research and regulatory interest in its carbon accounting. This paper examines one aspect of that carbon accounting: the baseline, i.e. the reference case against which other conditions or changes can be compared. A literature search and analysis identified four baseline types: no baseline; reference point; marginal fossil fuel; and biomass opportunity cost. The fourth one, biomass opportunity cost, is defined in more detail, because this is not done elsewhere in the literature. The four baselines are then applied to the carbon footprint of a wood-fired power plant. The footprint of the resulting wood-fired electricity varies dramatically, according to the type of baseline. Baseline type is also found to be the footprint's most significant sensitivity. Other significant sensitivities are: efficiency of the power plant; the growth (or re-growth) rate of the forest that supplies the wood; and the residue fraction of the wood. Length of the policy horizon is also an important factor in determining the footprint. The paper concludes that because of their significance and variability, baseline choices should be made very explicit in biofuel carbon footprints. - Highlights: Black-Right-Pointing-Pointer Four baseline types for biofuel footprinting are identified. Black-Right-Pointing-Pointer One type, 'biomass opportunity cost', is defined mathematically and graphically. Black-Right-Pointing-Pointer Choice of baseline can dramatically affect the footprint result. Black-Right-Pointing-Pointer The 'no baseline' approach is not acceptable. Black-Right-Pointing-Pointer Choice between the other three baselines depends on the question being addressed.

Evaluation of corrosive behavior of SAE 5155 by corrosion environment

International Nuclear Information System (INIS)

An, Jae Pil; Park, Keyung Dong

2005-01-01

In this study, the influence of shot peening and corrosive condition for corrosion property was investigated on immersed in 3.5% NaCl, 10% HNO 3 + 3% HF, 6% FeCl 3 . The immersion test was performed on two kinds of specimen. The immersion periods was performed 30days. Corrosion potential, weight loss were investigated from experimental results. From test results, the effect of shot peening on the corrosion was evaluated

Automated baseline change detection phase I. Final report

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-12-01

The Automated Baseline Change Detection (ABCD) project is supported by the DOE Morgantown Energy Technology Center (METC) as part of its ER&WM cross-cutting technology program in robotics. Phase 1 of the Automated Baseline Change Detection project is summarized in this topical report. The primary objective of this project is to apply robotic and optical sensor technology to the operational inspection of mixed toxic and radioactive waste stored in barrels, using Automated Baseline Change Detection (ABCD), based on image subtraction. Absolute change detection is based on detecting any visible physical changes, regardless of cause, between a current inspection image of a barrel and an archived baseline image of the same barrel. Thus, in addition to rust, the ABCD system can also detect corrosion, leaks, dents, and bulges. The ABCD approach and method rely on precise camera positioning and repositioning relative to the barrel and on feature recognition in images. In support of this primary objective, there are secondary objectives to determine DOE operational inspection requirements and DOE system fielding requirements.

Automated baseline change detection phase I. Final report

International Nuclear Information System (INIS)

1995-12-01

The Automated Baseline Change Detection (ABCD) project is supported by the DOE Morgantown Energy Technology Center (METC) as part of its ER ampersand WM cross-cutting technology program in robotics. Phase 1 of the Automated Baseline Change Detection project is summarized in this topical report. The primary objective of this project is to apply robotic and optical sensor technology to the operational inspection of mixed toxic and radioactive waste stored in barrels, using Automated Baseline Change Detection (ABCD), based on image subtraction. Absolute change detection is based on detecting any visible physical changes, regardless of cause, between a current inspection image of a barrel and an archived baseline image of the same barrel. Thus, in addition to rust, the ABCD system can also detect corrosion, leaks, dents, and bulges. The ABCD approach and method rely on precise camera positioning and repositioning relative to the barrel and on feature recognition in images. In support of this primary objective, there are secondary objectives to determine DOE operational inspection requirements and DOE system fielding requirements

Vegetation Parameter Extraction Using Dual Baseline Polarimetric SAR Interferometry Data

Science.gov (United States)

Zhang, H.; Wang, C.; Chen, X.; Tang, Y.

2009-04-01

For vegetation parameter inversion, the single baseline polarimetric SAR interferometry (POLinSAR) technique, such as the three-stage method and the ESPRIT algorithm, is limited by the observed data with the minimum ground to volume amplitude ration, which effects the estimation of the effective phase center for the vegetation canopy or the surface, and thus results in the underestimated vegetation height. In order to remove this effect of the single baseline inversion techniques in some extend, another baseline POLinSAR data is added on vegetation parameter estimation in this paper, and a dual baseline POLinSAR technique for the extraction of the vegetation parameter is investigated and improved to reduce the dynamic bias for the vegetation parameter estimation. Finally, the simulated data and real data are used to validate this dual baseline technique.

Information architecture. Volume 2, Part 1: Baseline analysis summary

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-12-01

The Department of Energy (DOE) Information Architecture, Volume 2, Baseline Analysis, is a collaborative and logical next-step effort in the processes required to produce a Departmentwide information architecture. The baseline analysis serves a diverse audience of program management and technical personnel and provides an organized way to examine the Department`s existing or de facto information architecture. A companion document to Volume 1, The Foundations, it furnishes the rationale for establishing a Departmentwide information architecture. This volume, consisting of the Baseline Analysis Summary (part 1), Baseline Analysis (part 2), and Reference Data (part 3), is of interest to readers who wish to understand how the Department`s current information architecture technologies are employed. The analysis identifies how and where current technologies support business areas, programs, sites, and corporate systems.

La comunicación de hoy, ¿una aberración?

Directory of Open Access Journals (Sweden)

Hugo Andrés Arévalo González

2013-12-01

Full Text Available Reseña del siguiente libro:MARTÍN-BARBERO, Jesús (2005. “Poner este roto país a comunicar”. En: Revista Signo y Pensamiento, Vol. XXIV, Núm. 46, Bogotá: Pontificia Universidad Javeriana. 163-169 pp

A study of man made radioactivity baseline in dietary materials

International Nuclear Information System (INIS)

de la Paz, L.; Estacio, J.; Palattao, M.V.; Anden, A.

1986-01-01

This paper describes the radioactivity baseline from literature data coming from various countries where data are available. 1979-1985 were chosen as the baseline years for the following: milk (fresh and powdered), meat and meat products, cereals, fruits, coffee and tea, fish and vegetables. Pre- and post-Chernobyl baseline data are given. (ELC). 21 figs; 17 refs

Validity and Reliability of Baseline Testing in a Standardized Environment.

Science.gov (United States)

Higgins, Kathryn L; Caze, Todd; Maerlender, Arthur

2017-08-11

The Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) is a computerized neuropsychological test battery commonly used to determine cognitive recovery from concussion based on comparing post-injury scores to baseline scores. This model is based on the premise that ImPACT baseline test scores are a valid and reliable measure of optimal cognitive function at baseline. Growing evidence suggests that this premise may not be accurate and a large contributor to invalid and unreliable baseline test scores may be the protocol and environment in which baseline tests are administered. This study examined the effects of a standardized environment and administration protocol on the reliability and performance validity of athletes' baseline test scores on ImPACT by comparing scores obtained in two different group-testing settings. Three hundred-sixty one Division 1 cohort-matched collegiate athletes' baseline data were assessed using a variety of indicators of potential performance invalidity; internal reliability was also examined. Thirty-one to thirty-nine percent of the baseline cases had at least one indicator of low performance validity, but there were no significant differences in validity indicators based on environment in which the testing was conducted. Internal consistency reliability scores were in the acceptable to good range, with no significant differences between administration conditions. These results suggest that athletes may be reliably performing at levels lower than their best effort would produce. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

On the roto-translatory internal motions of a three layer non-isobarycentric Earth model: a Lagrangian system approach

Science.gov (United States)

Escapa, Alberto; Fukushima, Toshio

2010-05-01

of this relative motion, three characteristic proper modes appear: one in the direction of the figure axis (polar mode) and two orthogonal to it (equatorial modes). These modes are usually referred as Slichter triplet. In the case of the polar mode, Busse (1974) determined analytically its expression in an implicit way; later other authors have obtained by numerical methods the values of all the modes (e.g Rieutord 2002). These expressions differ substantially from the single degenerate mode existing for a non-rotating model, the differences arising from the roto-traslatory coupling of the system. To construct an analytical description of the motion of this non-isobarycentric Earth model we have approximated it by a Lagrangian system, inspired in the successful of this variational approach to tackle the rotational dynamics of isobarycentric Earth models (e.g. Moritz 1982, Getino and Ferrándiz 2001). In this way, the fluid flow is represented as the sum of a rigid motion part plus a potential motion part. In this way, the resulting dynamical system is described by means of nine generalized co-ordinates. Once constructed the kinetic energy of each layer of the Earth model and the potential energy due to the gravitational interaction of the spherical rigid inner core with the fluid, we form the Euler-Lagrange equations of the system which turn out to be non-linear. By assuming a small departure with respect to the steady rotation configuration we linearice the differential equations of the motion, deriving from them the analytical expressions of the Slichter triplet. These expressions are compared with the existing numerical ones, appearing some discrepancies between both approaches. They might be caused by neglecting the non-linear terms in the resolution of the equations or by an incomplete description of the fluid flow. However, the numerical values of the modes derived with this treatment show a great improvement with respect to the values obtained from performing

Baseline effects on carbon footprints of biofuels: The case of wood

International Nuclear Information System (INIS)

Johnson, Eric; Tschudi, Daniel

2012-01-01

As biofuel usage has boomed over the past decade, so has research and regulatory interest in its carbon accounting. This paper examines one aspect of that carbon accounting: the baseline, i.e. the reference case against which other conditions or changes can be compared. A literature search and analysis identified four baseline types: no baseline; reference point; marginal fossil fuel; and biomass opportunity cost. The fourth one, biomass opportunity cost, is defined in more detail, because this is not done elsewhere in the literature. The four baselines are then applied to the carbon footprint of a wood-fired power plant. The footprint of the resulting wood-fired electricity varies dramatically, according to the type of baseline. Baseline type is also found to be the footprint's most significant sensitivity. Other significant sensitivities are: efficiency of the power plant; the growth (or re-growth) rate of the forest that supplies the wood; and the residue fraction of the wood. Length of the policy horizon is also an important factor in determining the footprint. The paper concludes that because of their significance and variability, baseline choices should be made very explicit in biofuel carbon footprints. - Highlights: ► Four baseline types for biofuel footprinting are identified. ► One type, ‘biomass opportunity cost’, is defined mathematically and graphically. ► Choice of baseline can dramatically affect the footprint result. ► The ‘no baseline’ approach is not acceptable. ► Choice between the other three baselines depends on the question being addressed.

Long baseline neutrino oscillation experiments

International Nuclear Information System (INIS)

Gallagher, H.

2006-01-01

In this paper I will review briefly the experimental results which established the existence of neutrino mixing, the current generation of long baseline accelerator experiments, and the prospects for the future. In particular I will focus on the recent analysis of the MINOS experiment. (author)

Baseline composition of solar energetic particles

International Nuclear Information System (INIS)

Meyer, J.

1985-01-01

We analyze all existing spacecraft observations of the highly variable heavy element composition of solar energetic particles (SEP) during non- 3 He-rich events. All data show the imprint of an ever-present basic composition pattern (dubbed ''mass-unbiased baseline'' SEP composition) that differs from the photospheric composition by a simple bias related to first ionization potential (FIP). In each particular observation, this mass-unbiased baseline composition is being distorted by an additional bias, which is always a monotonic function of mass (or Z). This latter bias varies in amplitude and even sign from observation to observation. To first order, it seems related to differences in the A/Z* ratio between elements (Z* = mean effective charge)

Magical properties of a 2540 km baseline superbeam experiment

International Nuclear Information System (INIS)

Raut, Sushant K.; Singh, Ravi Shanker; Uma Sankar, S.

2011-01-01

Lack of any information on the CP violating phase δ CP weakens our ability to determine neutrino mass hierarchy. Magic baseline of 7500 km was proposed to overcome this problem. However, to obtain large enough fluxes, at this very long baseline, one needs new techniques of generating high intensity neutrino beams. In this Letter, we highlight the magical properties of a 2540 km baseline. At such a baseline, using a narrow band neutrino superbeam whose no oscillation event rate peaks around the energy 3.5 GeV, we can determine neutrino mass hierarchy independently of the CP phase. For sin 2 2θ 13 ≥0.05, a very modest exposure of 10 Kiloton-years is sufficient to determine the hierarchy. For 0.02≤sin 2 2θ 13 ≤0.05, an exposure of about 100 Kiloton-years is needed.

Dynamic baseline detection method for power data network service

Science.gov (United States)

Chen, Wei

2017-08-01

This paper proposes a dynamic baseline Traffic detection Method which is based on the historical traffic data for the Power data network. The method uses Cisco's NetFlow acquisition tool to collect the original historical traffic data from network element at fixed intervals. This method uses three dimensions information including the communication port, time, traffic (number of bytes or number of packets) t. By filtering, removing the deviation value, calculating the dynamic baseline value, comparing the actual value with the baseline value, the method can detect whether the current network traffic is abnormal.

Forecasting Sensorimotor Adaptability from Baseline Inter-Trial Correlations

Science.gov (United States)

Beaton, K. H.; Bloomberg, J. J.

2014-01-01

One of the greatest challenges surrounding adaptation to the spaceflight environment is the large variability in symptoms, and corresponding functional impairments, from one crewmember to the next. This renders preflight training and countermeasure development difficult, as a "one-size-fits-all" approach is inappropriate. Therefore, it would be highly advantageous to know ahead of time which crewmembers might have more difficulty adjusting to the novel g-levels inherent to spaceflight. Such knowledge could guide individually customized countermeasures, which would enable more efficient use of crew time, both preflight and inflight, and provide better outcomes. The primary goal of this project is to look for a baseline performance metric that can forecast sensorimotor adaptability without exposure to an adaptive stimulus. We propose a novel hypothesis that considers baseline inter-trial correlations, the trial-to-trial fluctuations in motor performance, as a predictor of individual sensorimotor adaptive capabilities. To-date, a strong relationship has been found between baseline inter-trial correlations and adaptability in two oculomotor systems. For this project, we will explore an analogous predictive mechanism in the locomotion system. METHODS: Baseline Inter-trial Correlations: Inter-trial correlations specify the relationships among repeated trials of a given task that transpire as a consequence of correcting for previous performance errors over multiple timescales. We can quantify the strength of inter-trial correlations by measuring the decay of the autocorrelation function (ACF), which describes how rapidly information from past trials is "forgotten." Processes whose ACFs decay more slowly exhibit longer-term inter-trial correlations (longer memory processes), while processes whose ACFs decay more rapidly exhibit shorterterm inter-trial correlations (shorter memory processes). Longer-term correlations reflect low-frequency activity, which is more easily

Probing neutrino oscillations jointly in long and very long baseline experiments

International Nuclear Information System (INIS)

Wang, Y.F.; Whisnant, K.; Young Binglin; Xiong Zhaohua; Yang Jinmin

2002-01-01

We examine the prospects of making a joint analysis of neutrino oscillations at two baselines with neutrino superbeams. Assuming narrow band superbeams and a 100 kiloton water Cherenkov calorimeter, we calculate the event rates and sensitivities to the matter effect, the signs of the neutrino mass differences, the CP phase, and the mixing angle θ 13 . Taking into account all possible experimental errors under general consideration, we explore the optimum cases of a narrow band beam to measure the matter effect and the CP violation effect at all baselines up to 3000 km. We then focus on two specific baselines, a long baseline of 300 km and a very long baseline of 2100 km, and analyze their joint capabilities. We find that the joint analysis can offer extra leverage to resolve some of the ambiguities that are associated with the measurement at a single baseline

A baseline-free procedure for transformation models under interval censorship.

Science.gov (United States)

Gu, Ming Gao; Sun, Liuquan; Zuo, Guoxin

2005-12-01

An important property of Cox regression model is that the estimation of regression parameters using the partial likelihood procedure does not depend on its baseline survival function. We call such a procedure baseline-free. Using marginal likelihood, we show that an baseline-free procedure can be derived for a class of general transformation models under interval censoring framework. The baseline-free procedure results a simplified and stable computation algorithm for some complicated and important semiparametric models, such as frailty models and heteroscedastic hazard/rank regression models, where the estimation procedures so far available involve estimation of the infinite dimensional baseline function. A detailed computational algorithm using Markov Chain Monte Carlo stochastic approximation is presented. The proposed procedure is demonstrated through extensive simulation studies, showing the validity of asymptotic consistency and normality. We also illustrate the procedure with a real data set from a study of breast cancer. A heuristic argument showing that the score function is a mean zero martingale is provided.

Baseline cerebral oximetry values depend on non-modifiable patient characteristics.

Science.gov (United States)

Valencia, Lucía; Rodríguez-Pérez, Aurelio; Ojeda, Nazario; Santana, Romen Yone; Morales, Laura; Padrón, Oto

2015-12-01

The aim of the present study was to evaluate baseline regional cerebral oxygen saturation (rSO2) values and identify factors influencing preoperative rSO2 in elective minor surgery. Observational analysis post-hoc. Observational post-hoc analysis of data for the patient sample (n=50) of a previously conducted clinical trial in patients undergoing tumourectomy for breast cancer or inguinal hernia repair. Exclusion criteria included pre-existing cerebrovascular diseases, anaemia, baseline pulse oximetry values were recorded while the patient breathed room air, using the INVOS 5100C monitor™ (Covidien, Dublin, Ireland). Thirty-seven women (72%) and 13 men (28%) 48 ± 13 years of age were enrolled in this study. Baseline rSO2 was 62.01 ± 10.38%. Baseline rSO2 was significantly different between men (67.6 ± 11.2%) and women (60 ± 9.4%), (P=0.023). There were also differences between baseline rSO2 and ASA physical status (ASA I: 67.6 ± 10.7%, ASA II: 61.6 ± 8.4%, ASA III: 55.8 ± 13.9%, P=0.045). Baseline rSO2 had a positive correlation with body weight (r=0.347, P=0.014) and height (r=0.345, P=0.014). We also found significant differences in baseline rSO2 among patients with and without chronic renal failure (P=0.005). No differences were found in any other studied variables. Non-modifiable patient characteristics (ASA physical status, sex, chronic renal failure, body weight and height) influence baseline rSO2. Copyright © 2015 Société française d’anesthésie et de réanimation (Sfar). Published by Elsevier Masson SAS. All rights reserved.

Effects of Baseline Selection on Magnetocardiography: P-Q and T-P Intervals

International Nuclear Information System (INIS)

Lim, Hyun Kyoon; Kwon, Hyuk Chan; Kim, Tae En; Lee, Yong Ho; Kim, Jin Mok; Kim, In Seon; Kim, Ki Woong; Park, Yong Ki

2007-01-01

The baseline selection is the first and important step to analyze magnetocardiography (MCG) parameters. There are no difficulties to select the baseline between P- and Q-wave peak (P-Q interval) of MCG wave recorded from healthy subjects because the P-Q intervals of the healthy subjects do not much vary. However, patients with ischemic heart disease often show an unstable P-Q interval which does not seem to be appropriate for the baseline. In this case, T-P interval is alternatively recommended for the baseline. However, there has been no study on the difference made by the baseline selection. In this study, we studied the effect of the different baseline selection. MCG data were analyzed from twenty healthy subjects and twenty one patients whose baselines were alternatively selected in the T-P interval for their inappropriate P-Q interval. Paired T-test was used to compare two set of data. Fifteen parameters derived from the R-wave peak, the T-wave peak, and the period, T max/3 ∼ T max were compared for the different baseline selection. As a result, most parameters did not show significant differences (p>0.05) except few parameters. Therefore, there will be no significant differences if anyone of two intervals were selected for the MCG baseline. However, for the consistent analysis, P-Q interval is strongly recommended for the baseline correction.

40 CFR 80.915 - How are the baseline toxics value and baseline toxics volume determined?

Science.gov (United States)

2010-07-01

... baseline toxics value if it can determine an applicable toxics value for every batch of gasoline produced... of gasoline batch i produced or imported between January 1, 1998 and December 31, 2000, inclusive. i = Individual batch of gasoline produced or imported between January 1, 1998 and December 31, 2000, inclusive. n...

Residual stress control and design of next-generation ultra-hard gear steels

Science.gov (United States)

Qian, Yana

In high power density transmission systems, Ni-Co secondary hardening steels have shown great potential for next-generation gear applications due to their excellent strength, toughness and superior fatigue performance. Study of residual stress generation and evolution in Ferrium C61 and C67 gear steels revealed that shot peening and laser peening processes effectively produce desired beneficial residual stress in the steels for enhanced fatigue performance. Surface residual stress levels of -1.4GPa and -1.5GPa were achieved in shot peened C61 and laser peened C67, respectively, without introducing large surface roughness or defects. Higher compressive residual stress is expected in C67 according to a demonstrated correlation between attainable residual stress and material hardness. Due to the lack of appropriate shot media, dual laser peening is proposed for future peening optimization in C67. A novel non-destructive synchrotron radiation technique was implemented and applied for the first time for residual stress distribution analysis in gear steels with large composition and property gradients. Observed substantial residual stress redistribution and material microstructure change during the rolling contact fatigue screening test with extremely high 5.4GPa load indicates the unsuitability of the test as a fatigue life predictor. To exploit benefits of higher case hardness and associated residual stress, a new material and process (CryoForm70) aiming at 70Rc surface hardness was designed utilizing the systems approach based on thermodynamics and secondary hardening mechanisms. The composition design was first validated by the excellent agreement between experimental and theoretical core martensite start temperature in the prototype. A novel cryogenic deformation process was concurrently designed to increase the case martensite volume fraction from 76% to 92% for enhanced strengthening efficiency and surface hardness. High temperature vacuum carburizing was

Shifted Baselines Reduce Willingness to Pay for Conservation

Directory of Open Access Journals (Sweden)

Loren McClenachan

2018-02-01

Full Text Available A loss of memory of past environmental degradation has resulted in shifted baselines, which may result in conservation and restoration goals that are less ambitious than if stakeholders had a full knowledge of ecosystem potential. However, the link between perception of baseline states and support for conservation planning has not been tested empirically. Here, we investigate how perceptions of change in coral reef ecosystems affect stakeholders' willingness to pay (WTP for the establishment of protected areas. Coral reefs are experiencing rapid, global change that is observable by the public, and therefore provide an ideal ecosystem to test links between beliefs about baseline states and willingness to support conservation. Our survey respondents perceived change to coral reef communities across six variables: coral abundance, fish abundance, fish diversity, fish size, sedimentation, and water pollution. Respondants who accurately perceived declines in reef health had significantly higher WTP for protected areas (US $256.80 vs. $102.50 per year, suggesting that shifted baselines may reduce engagement with conservation efforts. If WTP translates to engagement, this suggests that goals for restoration and recovery are likely to be more ambitious if the public is aware of long term change. Therefore, communicating the scope and depth of environmental problems is essential in engaging the public in conservation.

Baseline Projection Data Book: GRI baseline projection of U.S. Energy Supply and Demand to 2010. 1992 Edition. Volume 1 and Volume 2

International Nuclear Information System (INIS)

Holtberg, P.D.; Woods, T.J.; Lihn, M.L.; Koklauner, A.K.

1992-01-01

The 1992 Baseline Projection Data Book provides backup data in tabular form for the 1992 GRI Baseline Projection of U.S. Energy Supply and Demand to 2010. Summary tables and data for the residential, commercial, industrial, electric utility, and transportation sectors are presented in the volume

Something of Value: How Franchise Sellers Make Training Pay

Science.gov (United States)

Berger, Gladys

1975-01-01

Training can be the most important benefit included in the purchase of a franchise. Several of these training programs used by franchise sellers (Castro Convertibles, Roto-Rooter, H and R Block, Dunhill Personnel Systems Inc., Carvel, Holiday Inns, Sheraton Inns Inc., McDonald's) are discussed. (Author/BP)

Baseline for the cumulants of net-proton distributions at STAR

International Nuclear Information System (INIS)

Luo, Xiaofeng; Mohanty, Bedangadas; Xu, Nu

2014-01-01

We present a systematic comparison between the recently measured cumulants of the net-proton distributions by STAR for 0–5% central Au + Au collisions at √(s NN )=7.7–200 GeV and two kinds of possible baseline measure, the Poisson and Binomial baselines. These baseline measures are assuming that the proton and anti-proton distributions independently follow Poisson statistics or Binomial statistics. The higher order cumulant net-proton data are observed to deviate from all the baseline measures studied at 19.6 and 27 GeV. We also compare the net-proton with net-baryon fluctuations in UrQMD and AMPT model, and convert the net-proton fluctuations to net-baryon fluctuations in AMPT model by using a set of formula

Parametric estimation of time varying baselines in airborne interferometric SAR

DEFF Research Database (Denmark)

Mohr, Johan Jacob; Madsen, Søren Nørvang

1996-01-01

A method for estimation of time varying spatial baselines in airborne interferometric synthetic aperture radar (SAR) is described. The range and azimuth distortions between two images acquired with a non-linear baseline are derived. A parametric model of the baseline is then, in a least square...... sense, estimated from image shifts obtained by cross correlation of numerous small patches throughout the image. The method has been applied to airborne EMISAR imagery from the 1995 campaign over the Storstrommen Glacier in North East Greenland conducted by the Danish Center for Remote Sensing. This has...... reduced the baseline uncertainties from several meters to the centimeter level in a 36 km scene. Though developed for airborne SAR the method can easily be adopted to satellite data...

The Effect of Pretest Exercise on Baseline Computerized Neurocognitive Test Scores.

Science.gov (United States)

Pawlukiewicz, Alec; Yengo-Kahn, Aaron M; Solomon, Gary

2017-10-01

Baseline neurocognitive assessment plays a critical role in return-to-play decision making following sport-related concussions. Prior studies have assessed the effect of a variety of modifying factors on neurocognitive baseline test scores. However, relatively little investigation has been conducted regarding the effect of pretest exercise on baseline testing. The aim of our investigation was to determine the effect of pretest exercise on baseline Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) scores in adolescent and young adult athletes. We hypothesized that athletes undergoing self-reported strenuous exercise within 3 hours of baseline testing would perform more poorly on neurocognitive metrics and would report a greater number of symptoms than those who had not completed such exercise. Cross-sectional study; Level of evidence, 3. The ImPACT records of 18,245 adolescent and young adult athletes were retrospectively analyzed. After application of inclusion and exclusion criteria, participants were dichotomized into groups based on a positive (n = 664) or negative (n = 6609) self-reported history of strenuous exercise within 3 hours of the baseline test. Participants with a positive history of exercise were then randomly matched, based on age, sex, education level, concussion history, and hours of sleep prior to testing, on a 1:2 basis with individuals who had reported no pretest exercise. The baseline ImPACT composite scores of the 2 groups were then compared. Significant differences were observed for the ImPACT composite scores of verbal memory, visual memory, reaction time, and impulse control as well as for the total symptom score. No significant between-group difference was detected for the visual motor composite score. Furthermore, pretest exercise was associated with a significant increase in the overall frequency of invalid test results. Our results suggest a statistically significant difference in ImPACT composite scores between

FED baseline engineering studies report

Energy Technology Data Exchange (ETDEWEB)

Sager, P.H.

1983-04-01

Studies were carried out on the FED Baseline to improve design definition, establish feasibility, and reduce cost. Emphasis was placed on cost reduction, but significant feasibility concerns existed in several areas, and better design definition was required to establish feasibility and provide a better basis for cost estimates. Design definition and feasibility studies included the development of a labyrinth shield ring concept to prevent radiation streaming between the torus spool and the TF coil cryostat. The labyrinth shield concept which was developed reduced radiation streaming sufficiently to permit contact maintenance of the inboard EF coils. Various concepts of preventing arcing between adjacent shield sectors were also explored. It was concluded that installation of copper straps with molybdenum thermal radiation shields would provide the most reliable means of preventing arcing. Other design studies included torus spool electrical/structural concepts, test module shielding, torus seismic response, poloidal conditions in the magnets, disruption characteristics, and eddy current effects. These additional studies had no significant impact on cost but did confirm the feasibility of the basic FED Baseline concept.

FED baseline engineering studies report

International Nuclear Information System (INIS)

Sager, P.H.

1983-04-01

Studies were carried out on the FED Baseline to improve design definition, establish feasibility, and reduce cost. Emphasis was placed on cost reduction, but significant feasibility concerns existed in several areas, and better design definition was required to establish feasibility and provide a better basis for cost estimates. Design definition and feasibility studies included the development of a labyrinth shield ring concept to prevent radiation streaming between the torus spool and the TF coil cryostat. The labyrinth shield concept which was developed reduced radiation streaming sufficiently to permit contact maintenance of the inboard EF coils. Various concepts of preventing arcing between adjacent shield sectors were also explored. It was concluded that installation of copper straps with molybdenum thermal radiation shields would provide the most reliable means of preventing arcing. Other design studies included torus spool electrical/structural concepts, test module shielding, torus seismic response, poloidal conditions in the magnets, disruption characteristics, and eddy current effects. These additional studies had no significant impact on cost but did confirm the feasibility of the basic FED Baseline concept

Baseline development, economic risk, and schedule risk: An integrated approach

International Nuclear Information System (INIS)

Tonkinson, J.A.

1994-01-01

The economic and schedule risks of Environmental Restoration (ER) projects are commonly analyzed toward the end of the baseline development process. Risk analysis is usually performed as the final element of the scheduling or estimating processes for the purpose of establishing cost and schedule contingency. However, there is an opportunity for earlier assessment of risks, during development of the technical scope and Work Breakdown Structure (WBS). Integrating the processes of risk management and baselining provides for early incorporation of feedback regarding schedule and cost risk into the proposed scope of work. Much of the information necessary to perform risk analysis becomes available during development of the technical baseline, as the scope of work and WBS are being defined. The analysis of risk can actually be initiated early on during development of the technical baseline and continue throughout development of the complete project baseline. Indeed, best business practices suggest that information crucial to the success of a project be analyzed and incorporated into project planning as soon as it is available and usable

Experimental study on the gasification characteristics of coal and orimulsion in 0.5 T/D gasifier

Energy Technology Data Exchange (ETDEWEB)

Park, Ho Young; Kim, Jong Young; An, Dal Hong; Park, Tae Jun [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center

1995-12-31

For the construction of commercial plant for IGCC imported from aboard in near future, it is aimed to get gasification data, practice the gasification design capability, and develop a fundamental key technology through the experiments for different kinds of coals (Datong, Roto, Alaska) by 0.5 T/D gasifier. We performed the experiments for physical properties and reactivities on selected coals by means of Drop Tube Reactor, numerical analysis for the reactor. Throughout the characteristic studies of orimulsion gasification, feasibility studies for orimulsion gasification as a fuel for power plant be performed. With the six experiment runs for the coal gasifier, several problems were found to remedy. After remedies, the gasifier could run at good operating conditions maintaining with 200% design feed rate over 1200-1550 degree. The third and fourth gasification runs with Roto were satisfactorily completed, during which gross heating values from produced gas were 7200-8200 Kcal/Nm{sup 3}. (author). 118 refs., 145 figs.

Experimental study on the gasification characteristics of coal and orimulsion in 0.5 T/D gasifier

Energy Technology Data Exchange (ETDEWEB)

Park, Ho Young; Kim, Jong Young; An, Dal Hong; Park, Tae Jun [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center

1996-12-31

For the construction of commercial plant for IGCC imported from aboard in near future, it is aimed to get gasification data, practice the gasification design capability, and develop a fundamental key technology through the experiments for different kinds of coals (Datong, Roto, Alaska) by 0.5 T/D gasifier. We performed the experiments for physical properties and reactivities on selected coals by means of Drop Tube Reactor, numerical analysis for the reactor. Throughout the characteristic studies of orimulsion gasification, feasibility studies for orimulsion gasification as a fuel for power plant be performed. With the six experiment runs for the coal gasifier, several problems were found to remedy. After remedies, the gasifier could run at good operating conditions maintaining with 200% design feed rate over 1200-1550 degree. The third and fourth gasification runs with Roto were satisfactorily completed, during which gross heating values from produced gas were 7200-8200 Kcal/Nm{sup 3}. (author). 118 refs., 145 figs.

Development of new duplex treatments on 100Cr6steel combining Thermochemical Treatments, Laser Shock Peening and Physical Vapour Deposition

International Nuclear Information System (INIS)

Osés, J.; Fuentes, G. G.; Santo Domingo, S.; Miguel, I.; Gimeno, S.; Carreras, L.; Peyre, P.; Gorny, C.

2017-01-01

100Cr6 steel (AISI 52100) is one of the most used steel grades in the manufacturing of through hardening bearings mainly due to its properties: controlled impurities during steel making process, high hardenability and well known mechanical properties such as wear and fatigue resistance on clean environments. These characteristics play an important role on the performance of a bearing together with the bearing design, loads and environment. However, there is an increasing set of demanding applications where the above mentioned steel does not fulfil the required needs and thus, bearing manufacturers continuously work on the development of technologies to improve the bearing performance. Nowadays thermochemical treatments (TCT), such as carbonitriding are being applied to this steel in order to enhance the performance of such pieces in contaminated environment, where particles can produce defects on the raceway, increasing the onset of defects that eventually lead to premature fail. These treatments induce the formation of carbides and nitrides which are directly related to the enhancement of the wear resistance and also to increasing the amount of Retained Austenite (RA) in the surface which may have a beneficial effect as it delays the crack propagation on subsurface regions, then increasing bearing fatigue life. In this work, different TCTs have been applied to 100Cr6 steel flat samples. Using a tribometer (ball-on-disc configuration) and a grinding machine, surface and in-depth wear resistance measurements have been carried out, obtaining wear resistance profiles that have been correlated with the microstructure, microhardness profiles and RA content. The most promising TCT has been combined either with Laser Shock Peening (LSP) treatments or carbonaceous Physical Vapour Deposition (PVD) coatings with the aim of improving not only the wear resistance but also the CoF of the duplex treated sample. The results obtained on flat samples are promising; the combination

Performance Analysis for Airborne Interferometric SAR Affected by Flexible Baseline Oscillation

Directory of Open Access Journals (Sweden)

Liu Zhong-sheng

2014-04-01

Full Text Available The airborne interferometric SAR platform suffers from instability factors, such as air turbulence and mechanical vibrations during flight. Such factors cause the oscillation of the flexible baseline, which leads to significant degradation of the performance of the interferometric SAR system. This study is concerned with the baseline oscillation. First, the error of the slant range model under baseline oscillation conditions is formulated. Then, the SAR complex image signal and dual-channel correlation coefficient are modeled based on the first-order, second-order, and generic slant range error. Subsequently, the impact of the baseline oscillation on the imaging and interferometric performance of the SAR system is analyzed. Finally, simulations of the echo data are used to validate the theoretical analysis of the baseline oscillation in the airborne interferometric SAR.

Influence of Baseline Psychological Health on Muscle Pain During Atorvastatin Treatment.

Science.gov (United States)

Zaleski, Amanda L; Taylor, Beth A; Pescatello, Linda S; Dornelas, Ellen A; White, Charles Michael; Thompson, Paul D

3-hydroxy-3-methylglutaryl coenzyme A reductase reductase inhibitors (statins) are generally well tolerated, with statin-associated muscle symptoms (SAMS) the most common side effect (~10%) seen in statin users. However, studies and clinical observations indicate that many of the self-reported SAMS appear to be nonspecific (ie, potentially not attributable to statins). Mental health and well-being influence self-perception of pain, so we sought to assess the effect of baseline well-being and depression on the development of muscle pain with 6 months of atorvastatin 80 mg/d (ATORVA) or placebo in healthy, statin-naive adults. The Psychological General Well-being Index (n = 83) and Beck Depression Inventory (n = 55) questionnaires were administered at baseline in participants (aged 59.5 ± 1.2 years) from the effect of Statins on Skeletal Muscle Function and Performance (STOMP) trial (NCT00609063). Muscle pain (Short-Form McGill Pain Questionnaire [SF-MPQ]), pain that interferes with daily life (Brief Pain Inventory [BPI]), and pain severity (BPI) were then measured before, throughout, and after treatment. At baseline, there were no differences in well-being (Psychological General Well-being Index), depression (Beck Depression Inventory), or pain measures (SF-MPQ and BPI) (P values ≥ .05) between the placebo and ATORVA groups. Baseline well-being correlated negatively with baseline BPI pain severity (r = -0.290, P = .008). Baseline depression correlated with baseline pain (SF-MPQ; r = 0.314, P = .020). Baseline well-being and depression did not predict the change in pain severity or interference after 6 months among the total sample or between groups (P values ≥ .05). Baseline well-being and depression were not significant predictors of pain after 6 months of ATORVA (P values ≥ .05). Thus, they do not appear to increase the risk of SAMS in otherwise healthy adults.

Baseline Report on HB2320

Science.gov (United States)

State Council of Higher Education for Virginia, 2015

2015-01-01

Staff provides this baseline report as a summary of its preliminary considerations and initial research in fulfillment of the requirements of HB2320 from the 2015 session of the General Assembly. Codified as § 23-7.4:7, this legislation compels the Education Secretary and the State Council of Higher Education for Virginia (SCHEV) Director, in…

Pediatric Heart Transplantation: Transitioning to Adult Care (TRANSIT): Baseline Findings.

Science.gov (United States)

Grady, Kathleen L; Hof, Kathleen Van't; Andrei, Adin-Cristian; Shankel, Tamara; Chinnock, Richard; Miyamoto, Shelley; Ambardekar, Amrut V; Anderson, Allen; Addonizio, Linda; Latif, Farhana; Lefkowitz, Debra; Goldberg, Lee; Hollander, Seth A; Pham, Michael; Weissberg-Benchell, Jill; Cool, Nichole; Yancy, Clyde; Pahl, Elfriede

2018-02-01

Young adult solid organ transplant recipients who transfer from pediatric to adult care experience poor outcomes related to decreased adherence to the medical regimen. Our pilot trial for young adults who had heart transplant (HT) who transfer to adult care tests an intervention focused on increasing HT knowledge, self-management and self-advocacy skills, and enhancing support, as compared to usual care. We report baseline findings between groups regarding (1) patient-level outcomes and (2) components of the intervention. From 3/14 to 9/16, 88 subjects enrolled and randomized to intervention (n = 43) or usual care (n = 45) at six pediatric HT centers. Patient self-report questionnaires and medical records data were collected at baseline, and 3 and 6 months after transfer. For this report, baseline findings (at enrollment and prior to transfer to adult care) were analyzed using Chi-square and t-tests. Level of significance was p Baseline demographics were similar in the intervention and usual care arms: age 21.3 ± 3.2 vs 21.5 ± 3.3 years and female 44% vs 49%, respectively. At baseline, there were no differences between intervention and usual care for use of tacrolimus (70 vs 62%); tacrolimus level (mean ± SD = 6.5 ± 2.3 ng/ml vs 5.6 ± 2.3 ng/ml); average of the within patient standard deviation of the baseline mean tacrolimus levels (1.6 vs 1.3); and adherence to the medical regimen [3.6 ± 0.4 vs 3.5 ± 0.5 (1 = hardly ever to 4 = all of the time)], respectively. At baseline, both groups had a modest amount of HT knowledge, were learning self-management and self-advocacy, and perceived they were adequately supported. Baseline findings indicate that transitioning HT recipients lack essential knowledge about HT and have incomplete self-management and self-advocacy skills.

Baseline Optimization for the Measurement of CP Violation, Mass Hierarchy, and $\\theta_{23}$ Octant in a Long-Baseline Neutrino Oscillation Experiment

Energy Technology Data Exchange (ETDEWEB)

Bass, M. [Colorado State U.; Bishai, M. [Brookhaven; Cherdack, D. [Colorado State U.; Diwan, M. [Brookhaven; Djurcic, Z. [Argonne; Hernandez, J. [Houston U.; Lundberg, B. [Fermilab; Paolone, V. [Pittsburgh U.; Qian, X. [Brookhaven; Rameika, R. [Fermilab; Whitehead, L. [Houston U.; Wilson, R. J. [Colorado State U.; Worcester, E. [Brookhaven; Zeller, G. [Fermilab

2015-03-19

Next-generation long-baseline electron neutrino appearance experiments will seek to discover CP violation, determine the mass hierarchy and resolve the θ23 octant. In light of the recent precision measurements of θ13, we consider the sensitivity of these measurements in a study to determine the optimal baseline, including practical considerations regarding beam and detector performance. We conclude that a detector at a baseline of at least 1000 km in a wide-band muon neutrino beam is the optimal configuration.

Should Studies of Diabetes Treatment Stratification Correct for Baseline HbA1c?

Science.gov (United States)

Jones, Angus G.; Lonergan, Mike; Henley, William E.; Pearson, Ewan R.; Hattersley, Andrew T.; Shields, Beverley M.

2016-01-01

Aims Baseline HbA1c is a major predictor of response to glucose lowering therapy and therefore a potential confounder in studies aiming to identify other predictors. However, baseline adjustment may introduce error if the association between baseline HbA1c and response is substantially due to measurement error and regression to the mean. We aimed to determine whether studies of predictors of response should adjust for baseline HbA1c. Methods We assessed the relationship between baseline HbA1c and glycaemic response in 257 participants treated with GLP-1R agonists and assessed whether it reflected measurement error and regression to the mean using duplicate ‘pre-baseline’ HbA1c measurements not included in the response variable. In this cohort and an additional 2659 participants treated with sulfonylureas we assessed the relationship between covariates associated with baseline HbA1c and treatment response with and without baseline adjustment, and with a bias correction using pre-baseline HbA1c to adjust for the effects of error in baseline HbA1c. Results Baseline HbA1c was a major predictor of response (R2 = 0.19,β = -0.44,pHbA1c were associated with response, however these associations were weak or absent after adjustment for baseline HbA1c. Bias correction did not substantially alter associations. Conclusions Adjustment for the baseline HbA1c measurement is a simple and effective way to reduce bias in studies of predictors of response to glucose lowering therapy. PMID:27050911

Baseline series fragrance markers fail to predict contact allergy.

Science.gov (United States)

Mann, Jack; McFadden, John P; White, Jonathan M L; White, Ian R; Banerjee, Piu

2014-05-01

Negative patch test results with fragrance allergy markers in the European baseline series do not always predict a negative reaction to individual fragrance substances. To determine the frequencies of positive test reactions to the 26 fragrance substances for which labelling is mandatory in the EU, and how effectively reactions to fragrance markers in the baseline series predict positive reactions to the fragrance substances that are labelled. The records of 1951 eczema patients, routinely tested with the labelled fragrance substances and with an extended European baseline series in 2011 and 2012, were retrospectively reviewed. Two hundred and eighty-one (14.4%) (71.2% females) reacted to one or more allergens from the labelled-fragrance substance series and/or a fragrance marker from the European baseline series. The allergens that were positive with the greatest frequencies were cinnamyl alcohol (48; 2.46%), Evernia furfuracea (44; 2.26%), and isoeugenol (40; 2.05%). Of the 203 patients who reacted to any of the 26 fragrances in the labelled-fragrance substance series, only 117 (57.6%) also reacted to a fragrance marker in the baseline series. One hundred and seven (52.7%) reacted to either fragrance mix I or fragrance mix II, 28 (13.8%) reacted to Myroxylon pereirae, and 13 (6.4%) reacted to hydroxyisohexyl 3-cyclohexene carboxaldehyde. These findings confirm that the standard fragrance markers fail to identify patients with contact allergies to the 26 fragrances. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A publication database for optical long baseline interferometry

Science.gov (United States)

Malbet, Fabien; Mella, Guillaume; Lawson, Peter; Taillifet, Esther; Lafrasse, Sylvain

2010-07-01

Optical long baseline interferometry is a technique that has generated almost 850 refereed papers to date. The targets span a large variety of objects from planetary systems to extragalactic studies and all branches of stellar physics. We have created a database hosted by the JMMC and connected to the Optical Long Baseline Interferometry Newsletter (OLBIN) web site using MySQL and a collection of XML or PHP scripts in order to store and classify these publications. Each entry is defined by its ADS bibcode, includes basic ADS informations and metadata. The metadata are specified by tags sorted in categories: interferometric facilities, instrumentation, wavelength of operation, spectral resolution, type of measurement, target type, and paper category, for example. The whole OLBIN publication list has been processed and we present how the database is organized and can be accessed. We use this tool to generate statistical plots of interest for the community in optical long baseline interferometry.

Back-calculating baseline creatinine overestimates prevalence of acute kidney injury with poor sensitivity.

Science.gov (United States)

Kork, F; Balzer, F; Krannich, A; Bernardi, M H; Eltzschig, H K; Jankowski, J; Spies, C

2017-03-01

Acute kidney injury (AKI) is diagnosed by a 50% increase in creatinine. For patients without a baseline creatinine measurement, guidelines suggest estimating baseline creatinine by back-calculation. The aim of this study was to evaluate different glomerular filtration rate (GFR) equations and different GFR assumptions for back-calculating baseline creatinine as well as the effect on the diagnosis of AKI. The Modification of Diet in Renal Disease, the Chronic Kidney Disease Epidemiology (CKD-EPI) and the Mayo quadratic (MQ) equation were evaluated to estimate baseline creatinine, each under the assumption of either a fixed GFR of 75 mL min -1  1.73 m -2 or an age-adjusted GFR. Estimated baseline creatinine, diagnoses and severity stages of AKI based on estimated baseline creatinine were compared to measured baseline creatinine and corresponding diagnoses and severity stages of AKI. The data of 34 690 surgical patients were analysed. Estimating baseline creatinine overestimated baseline creatinine. Diagnosing AKI based on estimated baseline creatinine had only substantial agreement with AKI diagnoses based on measured baseline creatinine [Cohen's κ ranging from 0.66 (95% CI 0.65-0.68) to 0.77 (95% CI 0.76-0.79)] and overestimated AKI prevalence with fair sensitivity [ranging from 74.3% (95% CI 72.3-76.2) to 90.1% (95% CI 88.6-92.1)]. Staging AKI severity based on estimated baseline creatinine had moderate agreement with AKI severity based on measured baseline creatinine [Cohen's κ ranging from 0.43 (95% CI 0.42-0.44) to 0.53 (95% CI 0.51-0.55)]. Diagnosing AKI and staging AKI severity on the basis of estimated baseline creatinine in surgical patients is not feasible. Patients at risk for post-operative AKI should have a pre-operative creatinine measurement to adequately assess post-operative AKI. © 2016 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Solid Waste Program technical baseline description

Energy Technology Data Exchange (ETDEWEB)

Carlson, A.B.

1994-07-01

The system engineering approach has been taken to describe the technical baseline under which the Solid Waste Program is currently operating. The document contains a mission analysis, function analysis, system definition, documentation requirements, facility and project bases, and uncertainties facing the program.

Geodesy by radio interferometry - Determinations of baseline vector, earth rotation, and solid earth tide parameters with the Mark I very long baseline radio interferometery system

Science.gov (United States)

Ryan, J. W.; Clark, T. A.; Coates, R. J.; Ma, C.; Wildes, W. T.

1986-01-01

Thirty-seven very long baseline radio interferometry experiments performed between 1972 and 1978 are analyzed and estimates of baseline vectors between six sites, five in the continental United States and one in Europe are derived. No evidence of significant changes in baseline length is found. For example, with a statistical level of confidence of approximately 85 percent, upper bounds on such changes within the United States ranged from a low of 10 mm/yr for the 850 km baseline between Westford, Massachusetts, and Green Bank, West Virginia, to a high of 90 mm/yr for the nearly 4000 km baseline between Westford and Goldstone, California. Estimates for universal time and for the x component of the position of the earth's pole are obtained. For the last 15 experiments, the only ones employing wideband receivers, the root-mean-square differences between the derived values and the corresponding ones published by the Bureau International de l'Heure are 0.0012 s and 0.018 arc sec respectively. The average value obtained for the radial Love number for the solid earth is 0.62 + or - 0.02 (estimated standard error).

Long-baseline neutrino oscillation experiments

International Nuclear Information System (INIS)

Crane, D.; Goodman, M.

1994-01-01

There is no unambiguous definition for long baseline neutrino oscillation experiments. The term is generally used for accelerator neutrino oscillation experiments which are sensitive to Δm 2 2 , and for which the detector is not on the accelerator site. The Snowmass N2L working group met to discuss the issues facing such experiments. The Fermilab Program Advisory Committee adopted several recommendations concerning the Fermilab neutrino program at their Aspen meeting immediately prior to the Snowmass Workshop. This heightened the attention for the proposals to use Fermilab for a long-baseline neutrino experiment at the workshop. The plan for a neutrino oscillation program at Brookhaven was also thoroughly discussed. Opportunities at CERN were considered, particularly the use of detectors at the Gran Sasso laboratory. The idea to build a neutrino beam from KEK towards Superkamiokande was not discussed at the Snowmass meeting, but there has been considerable development of this idea since then. Brookhaven and KEK would use low energy neutrino beams, while FNAL and CERN would plan have medium energy beams. This report will summarize a few topics common to LBL proposals and attempt to give a snapshot of where things stand in this fast developing field

40 CFR 80.1285 - How does a refiner apply for a benzene baseline?

Science.gov (United States)

2010-07-01

... baseline? 80.1285 Section 80.1285 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... (abt) Program § 80.1285 How does a refiner apply for a benzene baseline? (a) A benzene baseline... credits. (b) For U.S. Postal delivery, the benzene baseline application shall be sent to: Attn: MSAT2...

Analysis of Seasonal Signal in GPS Short-Baseline Time Series

Science.gov (United States)

Wang, Kaihua; Jiang, Weiping; Chen, Hua; An, Xiangdong; Zhou, Xiaohui; Yuan, Peng; Chen, Qusen

2018-04-01

Proper modeling of seasonal signals and their quantitative analysis are of interest in geoscience applications, which are based on position time series of permanent GPS stations. Seasonal signals in GPS short-baseline (paper, to better understand the seasonal signal in GPS short-baseline time series, we adopted and processed six different short-baselines with data span that varies from 2 to 14 years and baseline length that varies from 6 to 1100 m. To avoid seasonal signals that are overwhelmed by noise, each of the station pairs is chosen with significant differences in their height (> 5 m) or type of the monument. For comparison, we also processed an approximately zero baseline with a distance of pass-filtered (BP) noise is valid for approximately 40% of the baseline components, and another 20% of the components can be best modeled by a combination of the first-order Gauss-Markov (FOGM) process plus white noise (WN). The TEM displacements are then modeled by considering the monument height of the building structure beneath the GPS antenna. The median contributions of TEM to the annual amplitude in the vertical direction are 84% and 46% with and without additional parts of the monument, respectively. Obvious annual signals with amplitude > 0.4 mm in the horizontal direction are observed in five short-baselines, and the amplitudes exceed 1 mm in four of them. These horizontal seasonal signals are likely related to the propagation of daily/sub-daily TEM displacement or other signals related to the site environment. Mismodeling of the tropospheric delay may also introduce spurious seasonal signals with annual amplitudes of 5 and 2 mm, respectively, for two short-baselines with elevation differences greater than 100 m. The results suggest that the monument height of the additional part of a typical GPS station should be considered when estimating the TEM displacement and that the tropospheric delay should be modeled cautiously, especially with station pairs with

Remedial measures for nozzles susceptible to PWSCC

International Nuclear Information System (INIS)

Hunt, E.S.

1992-01-01

Remediating primary water stress corrosion cracking (PWSCC) is usually directed towards one of the three causes of PWSCC, material susceptiability, tensile stress, and an aggressive environment. The most practical remedial measures for primary loop penetration of PWSCC are considered to be shot peening, electropolishing, stress relief, and electroplating. The objective of shot peening is to induce a comprehensive residual stress on surfaces of Inconel 600 which are exposed to aggressive environments. Experience with steam generator tubes has shown this method is most effective if applied before PWSCC occurs. If it has already occurred, then the peening may retard but not arrest the corrosion. Electroplating consists of plating the inside surface of the Inconel 600 penetration with pure nickel. One of the major problems with this method was in obtaining surfaces uniformly free from pitting and roughness. Electropolishing for PWSCC remediation would remove the high strength cold work surfaces on the insides of nozzles which are produced by mechanical working e.g. machining. 5 figs

IEA Wind Task 26: Offshore Wind Farm Baseline Documentation

Energy Technology Data Exchange (ETDEWEB)

Smart, Gavin [Offshore Renewable Energy Catapult, Blyth, Northumberland (United Kingdom); Smith, Aaron [National Renewable Energy Lab. (NREL), Golden, CO (United States); Warner, Ethan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sperstad, Iver Bakken [SINTEF Energy Research, Trondheim (Norway); Prinsen, Bob [Ecofys, Utrecht (Netherlands). TKI Wind Op Zee; Lacal-Arantegui, Roberto [European Commission Joint Research Centre (JRC), Brussels (Belgium)

2016-06-02

This document has been produced to provide the definition and rationale for the Baseline Offshore Wind Farm established within IEA Wind Task 26--Cost of Wind Energy. The Baseline has been developed to provide a common starting point for country comparisons and sensitivity analysis on key offshore wind cost and value drivers. The baseline project reflects an approximate average of the characteristics of projects installed between 2012 and 2014, with the project life assumed to be 20 years. The baseline wind farm is located 40 kilometres (km) from construction and operations and maintenance (O&M) ports and from export cable landfall. The wind farm consists of 100 4-megawatt (MW) wind turbines mounted on monopile foundations in an average water depth of 25 metres (m), connected by 33-kilovolt (kV) inter-array cables. The arrays are connected to a single offshore substation (33kV/220kV) mounted on a jacket foundation, with the substation connected via a single 220kV export cable to an onshore substation, 10km from landfall. The wind farm employs a port-based O&M strategy using crew-transfer vessels.

Consideration of the baseline environment in examples of voluntary SEAs from Scotland

International Nuclear Information System (INIS)

Wright, Fiona

2007-01-01

Evidence from analysing and evaluating examples of three voluntary SEAs prepared in Scotland in the mid-late 1990s showed that different spatial and temporal scales were used when providing a baseline environment description. The SEAs analysed were prepared for: a wind farm siting programme that looked at national and short-term impacts; a land use plan that looked at regional and short-term impacts; and a transport plan that examined local and medium-term impacts. It was found that the two SEAs prepared by local government only considered impacts on the baseline environment within their jurisdictional boundaries whilst the SEA prepared by the private business considered impacts on the national baseline. A mixture of baseline data about planning, economic, environmental and social issues were included in the SEAs, however, evidence suggested that each SEA only focussed on those baseline features that might be significantly affected by the proposal. Each SEA also made extensive use of existing baseline information available from a variety of sources including local, and central government records and information from statutory bodies. All of the SEAs acknowledged that baseline data deficiencies existed and in certain cases steps were taken to obtain primary field data to help address these, however, it was also acknowledged that resource restrictions and decision-making deadlines limited the amount of primary baseline data that could be collected

Baselining PMU Data to Find Patterns and Anomalies

Energy Technology Data Exchange (ETDEWEB)

Amidan, Brett G.; Follum, James D.; Freeman, Kimberly A.; Dagle, Jeffery E.

2016-10-25

This paper looks at the application of situational awareness methodologies with respect to power grid data. These methodologies establish baselines that look for typical patterns and atypical behavior in the data. The objectives of the baselining analyses are to provide: real-time analytics, the capability to look at historical trends and events, and reliable predictions of the near future state of the grid. Multivariate algorithms were created to establish normal baseline behavior and then score each moment in time according to its variance from the baseline. Detailed multivariate analytical techniques are described in this paper that produced ways to identify typical patterns and atypical behavior. In this case, atypical behavior is behavior that is unenvisioned. Visualizations were also produced to help explain the behavior that was identified mathematically. Examples are shown to help describe how to read and interpret the analyses and visualizations. Preliminary work has been performed on PMU data sets from BPA (Bonneville Power Administration) and EI (Eastern Interconnect). Actual results are not fully shown here because of confidentiality issues. Comparisons between atypical events found mathematically and actual events showed that many of the actual events are also atypical events; however there are many atypical events that do not correlate to any actual events. Additional work needs to be done to help classify the atypical events into actual events, so that the importance of the events can be better understood.

Expuestos: experiencia y vestigios del cuerpo roto

OpenAIRE

Ileana Diéguez

2012-01-01

El artículo discute la relación entre el arte y la violencia en la producción contemporánea de América Latina, la investigación de la hipérbole de horror, tanto en el espectáculo real como la memoria del dolor expresado en la obra de algunos artistas como Rosa María Robles y Álvaro Villalobos.

200-BP-5 operable unit Technical Baseline report

International Nuclear Information System (INIS)

Jacques, I.D.; Kent, S.K.

1991-10-01

This report supports development of a remedial investigation/feasibility study work plan for the 200-BP-5 operable unit. The report summarizes baseline information for waste sites and unplanned release sites located in the 200-BP-5 operable unit. The sites were investigated by the Technical Baseline Section of the Environmental Engineering Group, Westinghouse Hanford Company (Westinghouse Hanford). The investigation consisted of review and evaluation of current and historical Hanford Site reports, drawings, and photographs, and was supplemented with recent inspections of the Hanford Site and employee interviews. No field investigations or sampling were conducted

Environmental baselines: preparing for shale gas in the UK

Science.gov (United States)

Bloomfield, John; Manamsa, Katya; Bell, Rachel; Darling, George; Dochartaigh, Brighid O.; Stuart, Marianne; Ward, Rob

2014-05-01

Groundwater is a vital source of freshwater in the UK. It provides almost 30% of public water supply on average, but locally, for example in south-east England, it is constitutes nearly 90% of public supply. In addition to public supply, groundwater has a number of other uses including agriculture, industry, and food and drink production. It is also vital for maintaining river flows especially during dry periods and so is essential for maintaining ecosystem health. Recently, there have been concerns expressed about the potential impacts of shale gas development on groundwater. The UK has abundant shales and clays which are currently the focus of considerable interest and there is active research into their characterisation, resource evaluation and exploitation risks. The British Geological Survey (BGS) is undertaking research to provide information to address some of the environmental concerns related to the potential impacts of shale gas development on groundwater resources and quality. The aim of much of this initial work is to establish environmental baselines, such as a baseline survey of methane occurrence in groundwater (National methane baseline study) and the spatial relationships between potential sources and groundwater receptors (iHydrogeology project), prior to any shale gas exploration and development. The poster describes these two baseline studies and presents preliminary findings. BGS are currently undertaking a national survey of baseline methane concentrations in groundwater across the UK. This work will enable any potential future changes in methane in groundwater associated with shale gas development to be assessed. Measurements of methane in potable water from the Cretaceous, Jurassic and Triassic carbonate and sandstone aquifers are variable and reveal methane concentrations of up to 500 micrograms per litre, but the mean value is relatively low at documented in the range 2km. The geological modelling process will be presented and discussed

Evidence of the shifting baseline syndrome in ethnobotanical research.

Science.gov (United States)

Hanazaki, Natalia; Herbst, Dannieli Firme; Marques, Mel Simionato; Vandebroek, Ina

2013-11-14

The shifting baseline syndrome is a concept from ecology that can be analyzed in the context of ethnobotanical research. Evidence of shifting baseline syndrome can be found in studies dealing with intracultural variation of knowledge, when knowledge from different generations is compared and combined with information about changes in the environment and/or natural resources. We reviewed 84 studies published between 1993 and 2012 that made comparisons of ethnobotanical knowledge according to different age classes. After analyzing these studies for evidence of the shifting baseline syndrome (lower knowledge levels in younger generations and mention of declining abundance of local natural resources), we searched within these studies for the use of the expressions "cultural erosion", "loss of knowledge", or "acculturation". The studies focused on different groups of plants (e.g. medicinal plants, foods, plants used for general purposes, or the uses of specific important species). More than half of all 84 studies (57%) mentioned a concern towards cultural erosion or knowledge loss; 54% of the studies showed evidence of the shifting baseline syndrome; and 37% of the studies did not provide any evidence of shifting baselines (intergenerational knowledge differences but no information available about the abundance of natural resources). The general perception of knowledge loss among young people when comparing ethnobotanical repertoires among different age groups should be analyzed with caution. Changes in the landscape or in the abundance of plant resources may be associated with changes in ethnobotanical repertoires held by people of different age groups. Also, the relationship between the availability of resources and current plant use practices rely on a complexity of factors. Fluctuations in these variables can cause changes in the reference (baseline) of different generations and consequently be responsible for differences in intergenerational knowledge. Unraveling

A proposal to create an extension to the European baseline series.

Science.gov (United States)

Wilkinson, Mark; Gallo, Rosella; Goossens, An; Johansen, Jeanne D; Rustemeyer, Thomas; Sánchez-Pérez, Javier; Schuttelaar, Marie L; Uter, Wolfgang

2018-02-01

The current European baseline series consists of 30 allergens, and was last updated in 2015. To use data from the European Surveillance System on Contact Allergies (ESSCA) to propose an extension to the European baseline series in response to changes in environmental exposures. Data from departmental and national extensions to the baseline series, together with some temporary additions from departments contributing to the ESSCA, were collated during 2013-2014. In total, 31689 patients were patch tested in 46 European departments. Many departments and national groups already consider the current European baseline series to be a suboptimal screen, and use their own extensions to it. The haptens tested are heterogeneous, although there are some consistent themes. Potential haptens to include in an extension to the European baseline series comprise sodium metabisulfite, formaldehyde-releasing preservatives, additional markers of fragrance allergy, propolis, Compositae mix, and 2-hydroxyethyl methacrylate. In combination with other published work from the ESSCA, changes to the current European baseline series are proposed for discussion. As well as addition of the allergens listed above, it is suggested that primin and clioquinol should be deleted from the series, owing to reduced environmental exposure. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

41 CFR 109-1.5202 - Establishment of a personal property holdings baseline.

Science.gov (United States)

2010-07-01

... personal property holdings baseline. 109-1.5202 Section 109-1.5202 Public Contracts and Property Management...-1.5202 Establishment of a personal property holdings baseline. (a) If the contractor is a new... baseline or may perform a complete physical inventory of all personal property. This physical inventory is...

75 FR 30014 - Consumers Energy Company; Notice of Baseline Filing

Science.gov (United States)

2010-05-28

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR10-25-000] Consumers Energy Company; Notice of Baseline Filing May 21, 2010. Take notice that on May 17, 2010, Consumers Energy Company (Consumers) submitted a baseline filing of its Statement of Operating Conditions for the...

Waste management project technical baseline description

International Nuclear Information System (INIS)

Sederburg, J.P.

1997-01-01

A systems engineering approach has been taken to describe the technical baseline under which the Waste Management Project is currently operating. The document contains a mission analysis, function analysis, requirement analysis, interface definitions, alternative analysis, system definition, documentation requirements, implementation definitions, and discussion of uncertainties facing the Project

Historical baselines of coral cover on tropical reefs as estimated by expert opinion

Directory of Open Access Journals (Sweden)

Tyler D. Eddy

2018-01-01

Full Text Available Coral reefs are important habitats that represent global marine biodiversity hotspots and provide important benefits to people in many tropical regions. However, coral reefs are becoming increasingly threatened by climate change, overfishing, habitat destruction, and pollution. Historical baselines of coral cover are important to understand how much coral cover has been lost, e.g., to avoid the ‘shifting baseline syndrome’. There are few quantitative observations of coral reef cover prior to the industrial revolution, and therefore baselines of coral reef cover are difficult to estimate. Here, we use expert and ocean-user opinion surveys to estimate baselines of global coral reef cover. The overall mean estimated baseline coral cover was 59% (±19% standard deviation, compared to an average of 58% (±18% standard deviation estimated by professional scientists. We did not find evidence of the shifting baseline syndrome, whereby respondents who first observed coral reefs more recently report lower estimates of baseline coral cover. These estimates of historical coral reef baseline cover are important for scientists, policy makers, and managers to understand the extent to which coral reefs have become depleted and to set appropriate recovery targets.

Historical baselines of coral cover on tropical reefs as estimated by expert opinion.

Science.gov (United States)

Eddy, Tyler D; Cheung, William W L; Bruno, John F

2018-01-01

Coral reefs are important habitats that represent global marine biodiversity hotspots and provide important benefits to people in many tropical regions. However, coral reefs are becoming increasingly threatened by climate change, overfishing, habitat destruction, and pollution. Historical baselines of coral cover are important to understand how much coral cover has been lost, e.g., to avoid the 'shifting baseline syndrome'. There are few quantitative observations of coral reef cover prior to the industrial revolution, and therefore baselines of coral reef cover are difficult to estimate. Here, we use expert and ocean-user opinion surveys to estimate baselines of global coral reef cover. The overall mean estimated baseline coral cover was 59% (±19% standard deviation), compared to an average of 58% (±18% standard deviation) estimated by professional scientists. We did not find evidence of the shifting baseline syndrome, whereby respondents who first observed coral reefs more recently report lower estimates of baseline coral cover. These estimates of historical coral reef baseline cover are important for scientists, policy makers, and managers to understand the extent to which coral reefs have become depleted and to set appropriate recovery targets.

Exploring non standard physics in long-baseline neutrino oscillation experiments

International Nuclear Information System (INIS)

Chatterjee, Sabya Sachi

2015-01-01

After the recent discovery of large th ( 13), the focus has been shifted to address the remaining fundamental issues like neutrino mass ordering and CP-violation in leptonic sector. Future proposed Long-Baseline facilities like DUNE (1300 km baseline from FNAL to Homestake) and LBNO (2290 km baseline from CERN to Pyhasalmi) are well suited to address these issues at high confidence level. Not only to the standard framework, these experiments are highly capable to look for some new physics beyond the Standard Model scenario. In this work, we explore whether these high precision future facilities are sensitive to new U(1) global symmetries and upto which confidence level. (author)

Way to increase the user access at the LCLS baseline

Energy Technology Data Exchange (ETDEWEB)

Geloni, Gianluca [European XFEL GmbH, Hamburg; Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2010-10-15

Although the LCLS photon beam is meant for a single user, the baseline undulator is long enough to serve two users simultaneously. To this end, we propose a setup composed of two simple elements: an X-ray mirror pair for X-ray beam deflection, and a short (4 m-long) magnetic chicane, which creates an offset for mirror pair installation in the middle of the baseline undulator. The insertable mirror pair can be used for spatial separation of the X-ray beams generated in the first and in the second half of the baseline undulator. The method of deactivating one half and activating another half of the undulator is based on the rapid switching of the FEL amplification process. As proposed elsewhere, using a kicker installed upstream of the LCLS baseline undulator and an already existing corrector in the first half of the undulator, it is possible to rapidly switch the X-ray beam from one user to another, thus providing two active beamlines at any time. We present simulation results dealing with the LCLS baseline, and show that it is possible to generate two saturated SASE X-ray beams in the whole 0.8-8 keV photon energy range in the same baseline undulator. These can be exploited to serve two users. Implementation of the proposed technique does not perturb the baseline mode of operation of the LCLS undulator. Moreover, the magnetic chicane setup is very flexible, and can be used as a self-seeding setup too. We present simulation results for the LCLS baseline undulator with SHAB (second harmonic afterburner) and show that one can produce monochromatic radiation at the 2nd harmonic as well as at the 1st. We describe an efficient way for obtaining multi-user operation at the LCLS hard X-ray FEL. To this end, a photon beam distribution system based on the use of crystals in the Bragg reflection geometry is proposed. The reflectivity of crystal deflectors can be switched fast enough by flipping the crystals with piezoelectric devices similar to those for X-ray phase retarders

Mechanical Thrombectomy in Elderly Stroke Patients with Mild-to-Moderate Baseline Disability.

Science.gov (United States)

Slawski, Diana E; Salahuddin, Hisham; Shawver, Julie; Kenmuir, Cynthia L; Tietjen, Gretchen E; Korsnack, Andrea; Zaidi, Syed F; Jumaa, Mouhammad A

2018-04-01

The number of elderly patients suffering from ischemic stroke is rising. Randomized trials of mechanical thrombectomy (MT) generally exclude patients over the age of 80 years with baseline disability. The aim of this study was to understand the efficacy and safety of MT in elderly patients, many of whom may have baseline impairment. Between January 2015 and April 2017, 96 patients ≥80 years old who underwent MT for stroke were selected for a chart review. The data included baseline characteristics, time to treatment, the rate of revascularization, procedural complications, mortality, and 90-day good outcome defined as a modified Rankin Scale (mRS) score of 0-2 or return to baseline. Of the 96 patients, 50 had mild baseline disability (mRS score 0-1) and 46 had moderate disability (mRS score 2-4). Recanalization was achieved in 84% of the patients, and the rate of symptomatic hemorrhage was 6%. At 90 days, 34% of the patients had a good outcome. There were no significant differences in good outcome between those with mild and those with moderate baseline disability (43 vs. 24%, p = 0.08), between those aged ≤85 and those aged > 85 years (40.8 vs. 26.1%, p = 0.19), and between those treated within and those treated beyond 8 h (39 vs. 20%, p = 0.1). The mortality rate was 38.5% at 90 days. The Alberta Stroke Program Early CT Score (ASPECTS) and the National Institutes of Health Stroke Scale (NIHSS) predicted good outcome regardless of baseline disability ( p baseline disability, and delayed treatment are associated with sub-optimal outcomes after MT. However, redefining good outcome to include return to baseline functioning demonstrates that one-third of this patient population benefits from MT, suggesting the real-life utility of this treatment.

77 FR 31841 - Hope Gas, Inc.; Notice of Baseline Filing

Science.gov (United States)

2012-05-30

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR12-23-001] Hope Gas, Inc.; Notice of Baseline Filing Take notice that on May 16, 2012, Hope Gas, Inc. (Hope Gas) submitted a revised baseline filing of their Statement of Operating Conditions for services provided under Section 311 of the...

77 FR 26535 - Hope Gas, Inc.; Notice of Baseline Filing

Science.gov (United States)

2012-05-04

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR12-23-000] Hope Gas, Inc.; Notice of Baseline Filing Take notice that on April 26, 2012, Hope Gas, Inc. (Hope Gas) submitted a baseline filing of their Statement of Operating Conditions for services provided under Section 311 of the...

75 FR 33799 - EasTrans, LLC; Notice of Baseline Filing

Science.gov (United States)

2010-06-15

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR10-30-000] EasTrans, LLC; Notice of Baseline Filing June 8, 2010. Take notice that on June 4, 2010, EasTrans, LLC submitted a baseline filing of its Statement of Operating Conditions for services provided under section 311 of the...

A Systematic Review and Meta-Analysis of Baseline Ohip-Edent Scores.

Science.gov (United States)

Duale, J M J; Patel, Y A; Wu, J; Hyde, T P

2018-03-01

OHIP-EDENT is widely used in the literature to assess Oral-Health-Related-Quality-of-Life (OHRQoL) for edentulous patients. However the normal variance and mean of the baseline OHIP scores has not been reported. It would facilitate critical appraisal of studies if we had knowledge of the normal variation and mean of baseline OHIP-EDENT scores. An established figure for baseline OHIP-EDENT, obtained from a meta-analysis, would simplify comparisons of studies and quantify variations in initial OHRQoL of the trial participants. The aim of this study is to quantify a normal baseline value for pre-operative OHIP-EDENT scores by a systematic review and meta-analysis of the available literature. A systematic literature review was carried. 83 papers were identified that included OHIP-EDENT values. After screening and eligibility assessment, 7 papers were selected and included in the meta-analysis. A meta-analysis for the 7 papers by a random-effect model yielded a mean baseline OHIP-EDENT score of 28.63 with a 95% Confidence intervals from 21.93 to 35.34. A pre-operative baseline OHIP-EDENT has been established by meta-analysis of published papers. This will facilitate the comparison of the initial OHRQoL of one study population to that found elsewhere in the published literature. Copyright© 2018 Dennis Barber Ltd.

Laser-Ultrasonic Testing and its Applications to Nuclear Reactor Internals

Science.gov (United States)

Ochiai, M.; Miura, T.; Yamamoto, S.

2008-02-01

A new nondestructive testing technique for surface-breaking microcracks in nuclear reactor components based on laser-ultrasonics is developed. Surface acoustic wave generated by Q-switched Nd:YAG laser and detected by frequency-stabilized long pulse laser coupled with confocal Fabry-Perot interferometer is used to detect and size the cracks. A frequency-domain signal processing is developed to realize accurate sizing capability. The laser-ultrasonic testing allows the detection of surface-breaking microcrack having a depth of less than 0.1 mm, and the measurement of their depth with an accuracy of 0.2 mm when the depth exceeds 0.5 mm including stress corrosion cracking. The laser-ultrasonic testing system combined with laser peening system, which is another laser-based maintenance technology to improve surface stress, for inner surface of small diameter tube is developed. The generation laser in the laser-ultrasonic testing system can be identical to the laser source of the laser peening. As an example operation of the system, the system firstly works as the laser-ultrasonic testing mode and tests the inner surface of the tube. If no cracks are detected, the system then changes its work mode to the laser peening and improves surface stress to prevent crack initiation. The first nuclear industrial application of the laser-ultrasonic testing system combined with the laser peening was completed in Japanese nuclear power plant in December 2004.

Base-line studies for DAE establishments

International Nuclear Information System (INIS)

Puranik, V.D.

2012-01-01

The Department of Atomic Energy has establishments located in various regions of the country and they include front-end fuel cycle facilities, nuclear power stations, back-end fuel cycle facilities and facilities for research and societal applications. These facilities handle naturally occurring radionuclides such as uranium, thorium and a variety of man-made radionuclides. These radionuclides are handled with utmost care so that they do not affect adversely the occupational workers or the members of public residing nearby. There is safety culture of the highest standard existing in all DAE establishments and it matches with the international standards. In addition, there is a perpetual environmental monitoring program carried out by the Environmental Survey Laboratories (ESLs) located at all DAE establishments. The environmental data generated by such program is studied regularly by experts to ensure compliance with the regulatory requirements. The regulatory requirements in the country are of international standards and ensure adequate protection of workers and members of public. In addition to such continued monitoring program and studies being carried out for the ongoing projects, base-line studies are carried out for all the new projects of the DAE. The purpose of the base-line studies is to establish a detailed base-line data set for a new DAE location well before the foundation stone is laid, so that the data collected when there is no departmental activity can be compared with the data generated later by the ESL. The data so generated is site specific and it varies from place to place depending upon the location of the site, e.g., inland or coastal, the presence of water bodies and pattern of irrigation, the geological characteristics of the location, the local culture and habits of the people, population density and urban or rural background. The data to be recorded as base-line data is generated over a period of at least one year covering all the seasons

National Cyberethics, Cybersafety, Cybersecurity Baseline Study

Science.gov (United States)

Education Digest: Essential Readings Condensed for Quick Review, 2009

2009-01-01

This article presents findings from a study that explores the nature of the Cyberethics, Cybersafety, and Cybersecurity (C3) educational awareness policies, initiatives, curriculum, and practices currently taking place in the U.S. public and private K-12 educational settings. The study establishes baseline data on C3 awareness, which can be used…

Linear MALDI-ToF simultaneous spectrum deconvolution and baseline removal.

Science.gov (United States)

Picaud, Vincent; Giovannelli, Jean-Francois; Truntzer, Caroline; Charrier, Jean-Philippe; Giremus, Audrey; Grangeat, Pierre; Mercier, Catherine

2018-04-05

Thanks to a reasonable cost and simple sample preparation procedure, linear MALDI-ToF spectrometry is a growing technology for clinical microbiology. With appropriate spectrum databases, this technology can be used for early identification of pathogens in body fluids. However, due to the low resolution of linear MALDI-ToF instruments, robust and accurate peak picking remains a challenging task. In this context we propose a new peak extraction algorithm from raw spectrum. With this method the spectrum baseline and spectrum peaks are processed jointly. The approach relies on an additive model constituted by a smooth baseline part plus a sparse peak list convolved with a known peak shape. The model is then fitted under a Gaussian noise model. The proposed method is well suited to process low resolution spectra with important baseline and unresolved peaks. We developed a new peak deconvolution procedure. The paper describes the method derivation and discusses some of its interpretations. The algorithm is then described in a pseudo-code form where the required optimization procedure is detailed. For synthetic data the method is compared to a more conventional approach. The new method reduces artifacts caused by the usual two-steps procedure, baseline removal then peak extraction. Finally some results on real linear MALDI-ToF spectra are provided. We introduced a new method for peak picking, where peak deconvolution and baseline computation are performed jointly. On simulated data we showed that this global approach performs better than a classical one where baseline and peaks are processed sequentially. A dedicated experiment has been conducted on real spectra. In this study a collection of spectra of spiked proteins were acquired and then analyzed. Better performances of the proposed method, in term of accuracy and reproductibility, have been observed and validated by an extended statistical analysis.

Atmospheric pressure loading parameters from very long baseline interferometry observations

Science.gov (United States)

Macmillan, D. S.; Gipson, John M.

1994-01-01

Atmospheric mass loading produces a primarily vertical displacement of the Earth's crust. This displacement is correlated with surface pressure and is large enough to be detected by very long baseline interferometry (VLBI) measurements. Using the measured surface pressure at VLBI stations, we have estimated the atmospheric loading term for each station location directly from VLBI data acquired from 1979 to 1992. Our estimates of the vertical sensitivity to change in pressure range from 0 to -0.6 mm/mbar depending on the station. These estimates agree with inverted barometer model calculations (Manabe et al., 1991; vanDam and Herring, 1994) of the vertical displacement sensitivity computed by convolving actual pressure distributions with loading Green's functions. The pressure sensitivity tends to be smaller for stations near the coast, which is consistent with the inverted barometer hypothesis. Applying this estimated pressure loading correction in standard VLBI geodetic analysis improves the repeatability of estimated lengths of 25 out of 37 baselines that were measured at least 50 times. In a root-sum-square (rss) sense, the improvement generally increases with baseline length at a rate of about 0.3 to 0.6 ppb depending on whether the baseline stations are close to the coast. For the 5998-km baseline from Westford, Massachusetts, to Wettzell, Germany, the rss improvement is about 3.6 mm out of 11.0 mm. The average rss reduction of the vertical scatter for inland stations ranges from 2.7 to 5.4 mm.

Safety Evaluation of the ESP Sludge Washing Baselines Runs. Revision 1

International Nuclear Information System (INIS)

Gupta, M.K.

1994-08-01

The purpose is to provide the technical basis for the evaluation of Unreviewed Safety Question for the Extended Sludge Processing (ESP) Sludge Washing Baseline Runs. The Baseline runs are necessary: to ascertain the mechanical fitness of the equipment and modifications not operated since 1988 and to resolve technical questions associated with process control; i.e., sludge suspension, sludge settling, heat transfer, and temperature control. These issues need to be resolved prior to resumption of normal ESP operations. The equipment used for the Baseline runs are Tanks 42H and 51H and their associated equipment

Network meta-analysis of disconnected networks: How dangerous are random baseline treatment effects?

Science.gov (United States)

Béliveau, Audrey; Goring, Sarah; Platt, Robert W; Gustafson, Paul

2017-12-01

In network meta-analysis, the use of fixed baseline treatment effects (a priori independent) in a contrast-based approach is regularly preferred to the use of random baseline treatment effects (a priori dependent). That is because, often, there is not a need to model baseline treatment effects, which carry the risk of model misspecification. However, in disconnected networks, fixed baseline treatment effects do not work (unless extra assumptions are made), as there is not enough information in the data to update the prior distribution on the contrasts between disconnected treatments. In this paper, we investigate to what extent the use of random baseline treatment effects is dangerous in disconnected networks. We take 2 publicly available datasets of connected networks and disconnect them in multiple ways. We then compare the results of treatment comparisons obtained from a Bayesian contrast-based analysis of each disconnected network using random normally distributed and exchangeable baseline treatment effects to those obtained from a Bayesian contrast-based analysis of their initial connected network using fixed baseline treatment effects. For the 2 datasets considered, we found that the use of random baseline treatment effects in disconnected networks was appropriate. Because those datasets were not cherry-picked, there should be other disconnected networks that would benefit from being analyzed using random baseline treatment effects. However, there is also a risk for the normality and exchangeability assumption to be inappropriate in other datasets even though we have not observed this situation in our case study. We provide code, so other datasets can be investigated. Copyright © 2017 John Wiley & Sons, Ltd.

Spent Nuclear Fuel Project technical baseline document. Fiscal year 1995: Volume 1, Baseline description

International Nuclear Information System (INIS)

Womack, J.C.; Cramond, R.; Paedon, R.J.

1995-01-01

This document is a revision to WHC-SD-SNF-SD-002, and is issued to support the individual projects that make up the Spent Nuclear Fuel Project in the lower-tier functions, requirements, interfaces, and technical baseline items. It presents results of engineering analyses since Sept. 1994. The mission of the SNFP on the Hanford site is to provide safety, economic, environmentally sound management of Hanford SNF in a manner that stages it to final disposition. This particularly involves K Basin fuel, although other SNF is involved also

Mass hierarchy sensitivity of medium baseline reactor neutrino experiments with multiple detectors

Energy Technology Data Exchange (ETDEWEB)

Wang, Hong-Xin, E-mail: hxwang@iphy.me [Department of Physics, Nanjing University, Nanjing 210093 (China); Zhan, Liang; Li, Yu-Feng; Cao, Guo-Fu [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Chen, Shen-Jian [Department of Physics, Nanjing University, Nanjing 210093 (China)

2017-05-15

We report the neutrino mass hierarchy (MH) determination of medium baseline reactor neutrino experiments with multiple detectors, where the sensitivity of measuring the MH can be significantly improved by adding a near detector. Then the impact of the baseline and target mass of the near detector on the combined MH sensitivity has been studied thoroughly. The optimal selections of the baseline and target mass of the near detector are ∼12.5 km and ∼4 kton respectively for a far detector with the target mass of 20 kton and the baseline of 52.5 km. As typical examples of future medium baseline reactor neutrino experiments, the optimal location and target mass of the near detector are selected for the specific configurations of JUNO and RENO-50. Finally, we discuss distinct effects of the reactor antineutrino energy spectrum uncertainty for setups of a single detector and double detectors, which indicate that the spectrum uncertainty can be well constrained in the presence of the near detector.

Dependence of optimum baseline setting on scatter fraction and detector response function

International Nuclear Information System (INIS)

Atkins, F.B.; Beck, R.N.; Hoffer, P.B.; Palmer, D.

1977-01-01

A theoretical and experimental investigation has been undertaken to determine the dependence of an optimum baseline setting on the amount of scattered radiation recorded in a spectrum, and on the energy resolution of the detector. In particular, baseline settings were established for clinical examinations which differed greatly in the amount of scattered radiation, namely, liver and brain scans, for which individual variations were found to produce only minimal fluctuations in the optimum baseline settings. This analysis resulted in an optimum baseline setting of 125.0 keV for brain scans and 127.2 keV for liver scans for the scintillation camera used in these studies. The criterion that was used is based on statistical considerations of the measurement of an unscattered component in the presence of a background due to scattered photons. The limitations of such a criterion are discussed, and phantom images are presented to illustrate these effects at various baseline settings. (author)

A comparison of baseline methodologies for 'Reducing Emissions from Deforestation and Degradation'

Directory of Open Access Journals (Sweden)

Kok Kasper

2009-07-01

Full Text Available Abstract Background A mechanism for emission reductions from deforestation and degradation (REDD is very likely to be included in a future climate agreement. The choice of REDD baseline methodologies will crucially influence the environmental and economic effectiveness of the climate regime. We compare three different historical baseline methods and one innovative dynamic model baseline approach to appraise their applicability under a future REDD policy framework using a weighted multi-criteria analysis. Results The results show that each baseline method has its specific strengths and weaknesses. Although the dynamic model allows for the best environmental and for comparatively good economic performance, its high demand for data and technical capacity limit the current applicability in many developing countries. Conclusion The adoption of a multi-tier approach will allow countries to select the baseline method best suiting their specific capabilities and data availability while simultaneously ensuring scientific transparency, environmental effectiveness and broad political support.

An Automatic Baseline Regulation in a Highly Integrated Receiver Chip for JUNO

Science.gov (United States)

Muralidharan, P.; Zambanini, A.; Karagounis, M.; Grewing, C.; Liebau, D.; Nielinger, D.; Robens, M.; Kruth, A.; Peters, C.; Parkalian, N.; Yegin, U.; van Waasen, S.

2017-09-01

This paper describes the data processing unit and an automatic baseline regulation of a highly integrated readout chip (Vulcan) for JUNO. The chip collects data continuously at 1 Gsamples/sec. The Primary data processing which is performed in the integrated circuit can aid to reduce the memory and data processing efforts in the subsequent stages. In addition, a baseline regulator compensating a shift in the baseline is described.

Stability analysis of geomagnetic baseline data obtained at Cheongyang observatory in Korea

Science.gov (United States)

Amran, Shakirah M.; Kim, Wan-Seop; Cho, Heh Ree; Park, Po Gyu

2017-07-01

The stability of baselines produced by Cheongyang (CYG) observatory from the period of 2014 to 2016 is analysed. Step heights of higher than 5 nT were found in H and Z components in 2014 and 2015 due to magnetic noise in the absolute-measurement hut. In addition, a periodic modulation behaviour observed in the H and Z baseline curves was related to annual temperature variation of about 20 °C in the fluxgate magnetometer hut. Improvement in data quality was evidenced by a small dispersion between successive measurements from June 2015 to the end of 2016. Moreover, the baseline was also improved by correcting the discontinuity in the H and Z baselines.

Stability analysis of geomagnetic baseline data obtained at Cheongyang observatory in Korea

Directory of Open Access Journals (Sweden)

S. M. Amran

2017-07-01

Full Text Available The stability of baselines produced by Cheongyang (CYG observatory from the period of 2014 to 2016 is analysed. Step heights of higher than 5 nT were found in H and Z components in 2014 and 2015 due to magnetic noise in the absolute-measurement hut. In addition, a periodic modulation behaviour observed in the H and Z baseline curves was related to annual temperature variation of about 20 °C in the fluxgate magnetometer hut. Improvement in data quality was evidenced by a small dispersion between successive measurements from June 2015 to the end of 2016. Moreover, the baseline was also improved by correcting the discontinuity in the H and Z baselines.

Corrective action baseline report for underground storage tank 2331-U Building 9201-1

International Nuclear Information System (INIS)

1994-01-01

The purpose of this report is to provide baseline geochemical and hydrogeologic data relative to corrective action for underground storage tank (UST) 2331-U at the Building 9201-1 Site. Progress in support of the Building 9201-1 Site has included monitoring well installation and baseline groundwater sampling and analysis. This document represents the baseline report for corrective action at the Building 9201-1 site and is organized into three sections. Section 1 presents introductory information relative to the site, including the regulatory initiative, site description, and progress to date. Section 2 includes the summary of additional monitoring well installation activities and the results of baseline groundwater sampling. Section 3 presents the baseline hydrogeology and planned zone of influence for groundwater remediation

77 FR 28373 - Liberty Energy (Midstates) Corp.; Notice of Baseline Filing

Science.gov (United States)

2012-05-14

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR12-24-000] Liberty Energy (Midstates) Corp.; Notice of Baseline Filing Take notice that on April 30, 2012, Liberty Energy (Midstates) Corp. submitted a baseline filing of their Statement of Operating Conditions for services provided...

Novel Method of Aluminum to Copper Bonding by Cold Spray

Science.gov (United States)

Fu, Si-Lin; Li, Cheng-Xin; Wei, Ying-Kang; Luo, Xiao-Tao; Yang, Guan-Jun; Li, Chang-Jiu; Li, Jing-Long

2018-04-01

Cold spray bonding (CSB) has been proposed as a new method for joining aluminum and copper. At high speeds, solid Al particles impacted the groove between the two substrates to form a bond between Al and Cu. Compared to traditional welding technologies, CSB does not form distinct intermetallic compounds. Large stainless steel particles were introduced into the spray powders as in situ shot peen particles to create a dense Al deposit and to improve the bond strength of joints. It was discovered that introducing shot peen particles significantly improved the flattening ratio of the deposited Al particles. Increasing the proportion of shot peen particles from 0 to 70 vol.% decreased the porosity of the deposits from 12.4 to 0.2%, while the shear strength of joints significantly increased. The tensile test results of the Al-Cu joints demonstrated that cracks were initiated at the interface between the Al and the deposit. The average tensile strength was 71.4 MPa and could reach 81% of the tensile strength of pure Al.

Improvement of Surface Layer Characteristics by Shot Lining

Science.gov (United States)

Harada, Yasunori

In the present study, lining of the metal with foils using shot peening was investigated to improve the surface layer characteristics. In the shot peening experiment, the foils set on the metal are pelted with hard particles traveling at a high velocity. The foils are bonded to the metal surface due to plastic deformation induced by the collision of the particles. The foils and the metal are heated to heighten the bondability because of the reduction of flow stress. Lining the metal with the hard powder sandwiched between two aluminum foil sheets was also attempted. In this experiment, a centrifugal shot peening machine wite an electrical heater was employed. The metals are commercially aluminium alloys and magnesium alloys, and the foils are commercially aluminum, titanium and nickel. The effects of shot speed and the heating temperature on the bondability were examined. Wear resistance was also evaluated by grinding. The foils were successfully bonded to the metal surface. It was found that the present method is effective in improving of surface layer characteristics.

Residual Stresses in a NiCrY-Coated Powder Metallurgy Disk Superalloy

Science.gov (United States)

Gabb, Timothy P.; Rogers, Richard B.; Nesbitt, James A.; Puleo, Bernadette J.; Miller, Robert A.; Telesman, Ignacy; Draper, Susan L.; Locci, Ivan E.

2017-01-01

Protective ductile coatings will be necessary to mitigate oxidation and corrosion attack on superalloy disks exposed to increasing operating temperatures in some turbine engine environments. However, such coatings must be resistant to harmful surface cracking during service. The objective of this study was to investigate how residual stresses evolve in such coatings. Cylindrical gage fatigue specimens of powder metallurgy-processed disk superalloy LSHR were coated with a NiCrY coating, shot peened, and then subjected to fatigue in air at room and high temperatures. The effects of shot peening and fatigue cycling on average residual stresses and other aspects of the coating were assessed. Shot peening did induce beneficial compressive residual stresses in the coating and substrate. However, these stresses became more tensile in the coating with subsequent heating and contributed to cracking of the coating in long intervals of cycling at 760 C. Substantial compressive residual stresses remained in the substrate adjacent to the coating, sufficient to suppress fatigue cracking. The coating continued to protect the substrate from hot corrosion pitting, even after fatigue cracks initiated in the coating.

Change Analysis in Structural Laser Scanning Point Clouds: The Baseline Method.

Science.gov (United States)

Shen, Yueqian; Lindenbergh, Roderik; Wang, Jinhu

2016-12-24

A method is introduced for detecting changes from point clouds that avoids registration. For many applications, changes are detected between two scans of the same scene obtained at different times. Traditionally, these scans are aligned to a common coordinate system having the disadvantage that this registration step introduces additional errors. In addition, registration requires stable targets or features. To avoid these issues, we propose a change detection method based on so-called baselines. Baselines connect feature points within one scan. To analyze changes, baselines connecting corresponding points in two scans are compared. As feature points either targets or virtual points corresponding to some reconstructable feature in the scene are used. The new method is implemented on two scans sampling a masonry laboratory building before and after seismic testing, that resulted in damages in the order of several centimeters. The centres of the bricks of the laboratory building are automatically extracted to serve as virtual points. Baselines connecting virtual points and/or target points are extracted and compared with respect to a suitable structural coordinate system. Changes detected from the baseline analysis are compared to a traditional cloud to cloud change analysis demonstrating the potential of the new method for structural analysis.

Change Analysis in Structural Laser Scanning Point Clouds: The Baseline Method

Directory of Open Access Journals (Sweden)

Yueqian Shen

2016-12-01

Full Text Available A method is introduced for detecting changes from point clouds that avoids registration. For many applications, changes are detected between two scans of the same scene obtained at different times. Traditionally, these scans are aligned to a common coordinate system having the disadvantage that this registration step introduces additional errors. In addition, registration requires stable targets or features. To avoid these issues, we propose a change detection method based on so-called baselines. Baselines connect feature points within one scan. To analyze changes, baselines connecting corresponding points in two scans are compared. As feature points either targets or virtual points corresponding to some reconstructable feature in the scene are used. The new method is implemented on two scans sampling a masonry laboratory building before and after seismic testing, that resulted in damages in the order of several centimeters. The centres of the bricks of the laboratory building are automatically extracted to serve as virtual points. Baselines connecting virtual points and/or target points are extracted and compared with respect to a suitable structural coordinate system. Changes detected from the baseline analysis are compared to a traditional cloud to cloud change analysis demonstrating the potential of the new method for structural analysis.

U-10Mo Baseline Fuel Fabrication Process Description

Energy Technology Data Exchange (ETDEWEB)

Hubbard, Lance R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Arendt, Christina L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dye, Daniel F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Clayton, Christopher K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lerchen, Megan E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lombardo, Nicholas J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zacher, Alan H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2017-09-27

This document provides a description of the U.S. High Power Research Reactor (USHPRR) low-enriched uranium (LEU) fuel fabrication process. This document is intended to be used in conjunction with the baseline process flow diagram (PFD) presented in Appendix A. The baseline PFD is used to document the fabrication process, communicate gaps in technology or manufacturing capabilities, convey alternatives under consideration, and as the basis for a dynamic simulation model of the fabrication process. The simulation model allows for the assessment of production rates, costs, and manufacturing requirements (manpower, fabrication space, numbers and types of equipment, etc.) throughout the lifecycle of the USHPRR program. This document, along with the accompanying PFD, is updated regularly

Spent nuclear fuel technical baseline description, Fiscal Year 1996: Volume II, supporting data

International Nuclear Information System (INIS)

Womack, J.C.

1995-11-01

The Technical Baseline Description documents the Project-Level functions and requirements, along with associated enabling assumptions, issues, trade studies, interfaces, and products. It is a snapshot in time of the baseline at the beginning of September 1995. It supports the individual subprojects in the development of lower-tier functions, requirements, and specifications in FY 1996. It also supports the need for Hanford site planning to be based on an integrated Hanford site systems engineering technical baseline; and is traceable to that baseline. This document replaces and supercedes WHC-SD-SNF-SD-003

75 FR 70732 - Enterprise Texas Pipeline LLC; Notice of Baseline Filing

Science.gov (United States)

2010-11-18

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR10-92-001] Enterprise Texas Pipeline LLC; Notice of Baseline Filing November 10, 2010. Take notice that on November 9, 2010, Enterprise Texas Pipeline LLC submitted a revised baseline filing of its Statement of Operating Conditions...

System maintenance test plan for the TWRS controlled baseline database system

International Nuclear Information System (INIS)

Spencer, S.G.

1998-01-01

TWRS [Tank Waste Remediation System] Controlled Baseline Database, formally known as the Performance Measurement Control System, is used to track and monitor TWRS project management baseline information. This document contains the maintenance testing approach for software testing of the TCBD system once SCR/PRs are implemented

40 CFR 80.290 - How does a refiner apply for a sulfur baseline?

Science.gov (United States)

2010-07-01

... baseline? 80.290 Section 80.290 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... (abt) Program-General Information § 80.290 How does a refiner apply for a sulfur baseline? (a) The... accordance with § 80.217. (b) The sulfur baseline request must be sent to: U.S. EPA, Attn: Sulfur Program...

Baseline inventory data recommendations for National Wildlife Refuges

Data.gov (United States)

Department of the Interior — The Baseline Inventory Team recommends that each refuge have available abiotic “data layers” for topography, aerial photography, hydrography, soils, boundaries, and...

Baseline for trust: defining 'new and additional' climate funding

Energy Technology Data Exchange (ETDEWEB)

Stadelmann, Martin [University of Zurich (Switzerland); Roberts, J. Timmons [Brown University (United States); Huq, Saleemul

2010-06-15

Climate finance is becoming a dark curve on the road from Copenhagen to Cancún. Poorer nations fear that richer ones will fulfil the US$30 billion 'fast-start' climate finance promises made in the non-binding Copenhagen Accord by relabelling or diverting basic development aid, or by simply delivering on past climate finance pledges. The problem is simple: contributor countries are operating with no clear baseline against which their promise of 'new and additional' funding can be counted – and they do not accept the baselines put forth by developing countries. A viable solution for the short term is to use projections of business-as-usual development assistance as baselines. The longer-term benchmark could be the provision of truly 'new' funds from new funding sources. Substantial up-front negotiations may be required, but seizing this opportunity to define baselines will build confidence on both sides and create predictability for future finance.

Office of Civilian Radioactive Waste Management Program Cost and Schedule Baseline

International Nuclear Information System (INIS)

1992-09-01

The purpose of this document is to establish quantitative expressions of proposed costs and schedule to serve as a basis for measurement of program performance. It identifies the components of the Program Cost and Schedule Baseline (PCSB) that will be subject to change control by the Executive (Level 0) and Program (Level 1) Change Control Boards (CCBS) and establishes their baseline values. This document also details PCSB reporting, monitoring, and corrective action requirements. The Program technical baseline contained in the Waste Management System Description (WMSD), the Waste Management System Requirements (WMSR), and the Physical System Requirements documents provide the technical basis for the PCSB. Changes to the PCSB will be approved by the Pregrain Change Control Board (PCCB)In addition to the PCCB, the Energy System Acquisition Advisory Board Baseline CCB (ESAAB BCCB) will perform control functions relating to Total Project Cost (TPC) and major schedule milestones for the Yucca Mountain Site Characterization Project and the Monitored Retrievable Storage (MRS) Project

Predicting Baseline for Analysis of Electricity Pricing

Energy Technology Data Exchange (ETDEWEB)

Kim, T. [Ulsan National Inst. of Science and Technology (Korea, Republic of); Lee, D. [Ulsan National Inst. of Science and Technology (Korea, Republic of); Choi, J. [Ulsan National Inst. of Science and Technology (Korea, Republic of); Spurlock, A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sim, A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Todd, A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wu, K. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-05-03

To understand the impact of new pricing structure on residential electricity demands, we need a baseline model that captures every factor other than the new price. The standard baseline is a randomized control group, however, a good control group is hard to design. This motivates us to devlop data-driven approaches. We explored many techniques and designed a strategy, named LTAP, that could predict the hourly usage years ahead. The key challenge in this process is that the daily cycle of electricity demand peaks a few hours after the temperature reaching its peak. Existing methods rely on the lagged variables of recent past usages to enforce this daily cycle. These methods have trouble making predictions years ahead. LTAP avoids this trouble by assuming the daily usage profile is determined by temperature and other factors. In a comparison against a well-designed control group, LTAP is found to produce accurate predictions.

CASA Uno GPS orbit and baseline experiments

Science.gov (United States)

Schutz, B. E.; Ho, C. S.; Abusali, P. A. M.; Tapley, B. D.

1990-01-01

CASA Uno data from sites distributed in longitude from Australia to Europe have been used to determine orbits of the GPS satellites. The characteristics of the orbits determined from double difference phase have been evaluated through comparisons of two-week solutions with one-week solutions and by comparisons of predicted and estimated orbits. Evidence of unmodeled effects is demonstrated, particularly associated with the orbit planes that experience solar eclipse. The orbit accuracy has been assessed through the repeatability of unconstrained estimated baseline vectors ranging from 245 km to 5400 km. Both the baseline repeatability and the comparison with independent space geodetic methods give results at the level of 1-2 parts in 100,000,000. In addition, the Mojave/Owens Valley (245 km) and Kokee Park/Ft. Davis (5409 km) estimates agree with VLBI and SLR to better than 1 part in 100,000,000.

Upper Extremity Radiography

Science.gov (United States)

... Estos tipos de exámenes se realizan para detectar estados tales huesos rotos, daños de los tejidos blandos y artritis. El médico le ... en interpretar las imágenes médicas de diagnóstico. Después de que el ... los resultados y conversará con usted sobre qué procedimientos adicionales ...

Development Of Regional Climate Mitigation Baseline For A DominantAgro-Ecological Zone Of Karnataka, India

Energy Technology Data Exchange (ETDEWEB)

Sudha, P.; Shubhashree, D.; Khan, H.; Hedge, G.T.; Murthy, I.K.; Shreedhara, V.; Ravindranath, N.H.

2007-06-01

Setting a baseline for carbon stock changes in forest andland use sector mitigation projects is an essential step for assessingadditionality of the project. There are two approaches for settingbaselines namely, project-specific and regional baseline. This paperpresents the methodology adopted for estimating the land available formitigation, for developing a regional baseline, transaction cost involvedand a comparison of project-specific and regional baseline. The studyshowed that it is possible to estimate the potential land and itssuitability for afforestation and reforestation mitigation projects,using existing maps and data, in the dry zone of Karnataka, southernIndia. The study adopted a three-step approach for developing a regionalbaseline, namely: i) identification of likely baseline options for landuse, ii) estimation of baseline rates of land-use change, and iii)quantification of baseline carbon profile over time. The analysis showedthat carbon stock estimates made for wastelands and fallow lands forproject-specific as well as the regional baseline are comparable. Theratio of wasteland Carbon stocks of a project to regional baseline is1.02, and that of fallow lands in the project to regional baseline is0.97. The cost of conducting field studies for determination of regionalbaseline is about a quarter of the cost of developing a project-specificbaseline on a per hectare basis. The study has shown the reliability,feasibility and cost-effectiveness of adopting regional baseline forforestry sectormitigation projects.

75 FR 38802 - DCP Raptor Pipeline, LLC; Notice of Baseline Filing

Science.gov (United States)

2010-07-06

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR10-42-000] DCP Raptor Pipeline, LLC; Notice of Baseline Filing June 28, 2010. Take notice that on June 22, 2010, DCP Raptor Pipeline, LLC submitted a baseline filing of its Statement of Operating Conditions for services provided...

Mass hierarchy sensitivity of medium baseline reactor neutrino experiments with multiple detectors

Directory of Open Access Journals (Sweden)

Hong-Xin Wang

2017-05-01

Full Text Available We report the neutrino mass hierarchy (MH determination of medium baseline reactor neutrino experiments with multiple detectors, where the sensitivity of measuring the MH can be significantly improved by adding a near detector. Then the impact of the baseline and target mass of the near detector on the combined MH sensitivity has been studied thoroughly. The optimal selections of the baseline and target mass of the near detector are ∼12.5 km and ∼4 kton respectively for a far detector with the target mass of 20 kton and the baseline of 52.5 km. As typical examples of future medium baseline reactor neutrino experiments, the optimal location and target mass of the near detector are selected for the specific configurations of JUNO and RENO-50. Finally, we discuss distinct effects of the reactor antineutrino energy spectrum uncertainty for setups of a single detector and double detectors, which indicate that the spectrum uncertainty can be well constrained in the presence of the near detector.

Guidance on Port Biological Baseline Surveys (PBBS)

Digital Repository Service at National Institute of Oceanography (India)

Awad, A.; Haag, F.; Anil, A.C.; Abdulla, A.

This publication has been prepared by GBP, IOI, CSIR-NIO and IUCN in order to serve as guidance to those who are planning to carry out a port biological baseline survey, in particular in the context of Ballast Water Management. It has been drafted...

Baseline and Multimodal UAV GCS Interface Design

Science.gov (United States)

2013-07-01

complete a computerized version of the NASA - TLX assessment of perceived mental workload. 2.3 Results The baseline condition ran smoothly and with...System MALE Medium-altitude, Long-endurance NASA - TLX NASA Task Load Index SA Situation Awareness TDT Tucker Davis Technologies UAV Uninhabited Aerial

48 CFR 34.202 - Integrated Baseline Reviews.

Science.gov (United States)

2010-10-01

... or contractor, and the Government, of the— (1) Ability of the project's technical plan to achieve the... successfully achieve the project schedule objectives; (3) Ability of the Performance Measurement Baseline (PMB... SPECIAL CATEGORIES OF CONTRACTING MAJOR SYSTEM ACQUISITION Earned Value Management System 34.202...

Baseline glucocorticoids are drivers of body mass gain in a diving seabird.

Science.gov (United States)

Hennin, Holly L; Wells-Berlin, Alicia M; Love, Oliver P

2016-03-01

Life-history trade-offs are influenced by variation in individual state, with individuals in better condition often completing life-history stages with greater success. Although resource accrual significantly impacts key life-history decisions such as the timing of reproduction, little is known about the underlying mechanisms driving resource accumulation. Baseline corticosterone (CORT, the primary avian glucocorticoid) mediates daily and seasonal energetics, responds to changes in food availability, and has been linked to foraging behavior, making it a strong potential driver of individual variation in resource accrual and deposition. Working with a captive colony of white-winged scoters (Melanitta fusca deglandi), we aimed to causally determine whether variation in baseline CORT drives individual body mass gains mediated through fattening rate (plasma triglycerides corrected for body mass). We implanted individuals with each of three treatment pellets to elevate CORT within a baseline range in a randomized order: control, low dose of CORT, high dose of CORT, then blood sampled and recorded body mass over a two-week period to track changes in baseline CORT, body mass, and fattening rates. The high CORT treatment significantly elevated levels of plasma hormone for a short period of time within the biologically relevant, baseline range for this species, but importantly did not inhibit the function of the HPA (hypothalamic-pituitary-adrenal) axis. Furthermore, an elevation in baseline CORT resulted in a consistent increase in body mass throughout the trial period compared to controls. This is some of the first empirical evidence demonstrating that elevations of baseline CORT within a biologically relevant range have a causal, direct, and positive influence on changes in body mass.

Baseline glucocorticoids are drivers of body mass gain in a diving seabird

Science.gov (United States)

Hennin, Holly; Berlin, Alicia; Love, Oliver P.

2016-01-01

Life-history trade-offs are influenced by variation in individual state, with individuals in better condition often completing life-history stages with greater success. Although resource accrual significantly impacts key life-history decisions such as the timing of reproduction, little is known about the underlying mechanisms driving resource accumulation. Baseline corticosterone (CORT, the primary avian glucocorticoid) mediates daily and seasonal energetics, responds to changes in food availability, and has been linked to foraging behavior, making it a strong potential driver of individual variation in resource accrual and deposition. Working with a captive colony of white-winged scoters (Melanitta fusca deglandi), we aimed to causally determine whether variation in baseline CORT drives individual body mass gains mediated through fattening rate (plasma triglycerides corrected for body mass). We implanted individuals with each of three treatment pellets to elevate CORT within a baseline range in a randomized order: control, low dose of CORT, high dose of CORT, then blood sampled and recorded body mass over a two-week period to track changes in baseline CORT, body mass, and fattening rates. The high CORT treatment significantly elevated levels of plasma hormone for a short period of time within the biologically relevant, baseline range for this species, but importantly did not inhibit the function of the HPA (hypothalamic–pituitary–adrenal) axis. Furthermore, an elevation in baseline CORT resulted in a consistent increase in body mass throughout the trial period compared to controls. This is some of the first empirical evidence demonstrating that elevations of baseline CORT within a biologically relevant range have a causal, direct, and positive influence on changes in body mass.

Item response theory analysis of the mechanics baseline test

Science.gov (United States)

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

2012-02-01

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

Information Technology Sector Baseline Risk Assessment

Science.gov (United States)

2009-08-01

alternative root be economically advantageous , an actor’s ability to exploit market forces and create an alternative root would be significantly improved...conduct their operations. Therefore, a loss or disruption to Internet services would not be advantageous for the desired outcomes of these syndicates.26... eCommerce Service loss or disruption [C] Traffic Redirection [C] = Undesired consequence Information Technology Sector Baseline Risk Assessment

The prognostic utility of baseline alpha-fetoprotein for hepatocellular carcinoma patients.

Science.gov (United States)

Silva, Jack P; Gorman, Richard A; Berger, Nicholas G; Tsai, Susan; Christians, Kathleen K; Clarke, Callisia N; Mogal, Harveshp; Gamblin, T Clark

2017-12-01

Alpha-fetoprotein (AFP) has a valuable role in postoperative surveillance for hepatocellular carcinoma (HCC) recurrence. The utility of pretreatment or baseline AFP remains controversial. The present study hypothesized that elevated baseline AFP levels are associated with worse overall survival in HCC patients. Adult HCC patients were identified using the National Cancer Database (2004-2013). Patients were stratified according to baseline AFP measurements into the following groups: Negative (2000). The primary outcome was overall survival (OS), which was analyzed by log-rank test and graphed using Kaplan-Meier method. Multivariate regression modeling was used to determine hazard ratios (HR) for OS. Of 41 107 patients identified, 15 809 (33.6%) were Negative. Median overall survival was highest in the Negative group, followed by Borderline, Elevated, and Highly Elevated (28.7 vs 18.9 vs 8.8 vs 3.2 months; P < 0.001). On multivariate analysis, overall survival hazard ratios for the Borderline, Elevated, and Highly Elevated groups were 1.18 (P = 0.267), 1.94 (P < 0.001), and 1.77 (P = 0.007), respectively (reference Negative). Baseline AFP independently predicted overall survival in HCC patients regardless of treatment plan. A baseline AFP value is a simple and effective method to assist in expected survival for HCC patients. © 2017 Wiley Periodicals, Inc.

Effect of computer game playing on baseline laparoscopic simulator skills.

Science.gov (United States)

Halvorsen, Fredrik H; Cvancarova, Milada; Fosse, Erik; Mjåland, Odd

2013-08-01

Studies examining the possible association between computer game playing and laparoscopic performance in general have yielded conflicting results and neither has a relationship between computer game playing and baseline performance on laparoscopic simulators been established. The aim of this study was to examine the possible association between previous and present computer game playing and baseline performance on a virtual reality laparoscopic performance in a sample of potential future medical students. The participating students completed a questionnaire covering the weekly amount and type of computer game playing activity during the previous year and 3 years ago. They then performed 2 repetitions of 2 tasks ("gallbladder dissection" and "traverse tube") on a virtual reality laparoscopic simulator. Performance on the simulator were then analyzed for association to their computer game experience. Local high school, Norway. Forty-eight students from 2 high school classes volunteered to participate in the study. No association between prior and present computer game playing and baseline performance was found. The results were similar both for prior and present action game playing and prior and present computer game playing in general. Our results indicate that prior and present computer game playing may not affect baseline performance in a virtual reality simulator.

Investigating the baselines of Bismuth, Optical Fiber and LED calibrated photomultiplier tubes

CERN Document Server

Evans, Hywel Turner

2016-01-01

LUCID is a detector that is the luminosity monitor for the ATLAS experiment, and its aim is to determine luminosity with an uncertainty of a few percent. The main purpose of this work is the study of the baseline stability of the LUCID readout channels during calibration runs. This study represents the first systematic approach of this problem performed by the LUCID group. By replacing the mean baseline with the minimum baseline of each event, an upper limit of 2.85% was placed upon possible improvement in determining the LED amplitude. It is therefore better to use a fixed baseline for LED, as pollution has been observed when calculating event by event. For Bismuth and Fiber, the improvement cannot be more than the gain stability of 1%, therefore the existing method is verified as optimal.

On the feasibility of routine baseline improvement in processing of geomagnetic observatory data

Science.gov (United States)

Soloviev, Anatoly; Lesur, Vincent; Kudin, Dmitry

2018-02-01

We propose a new approach to the calculation of regular baselines at magnetic observatories. The proposed approach is based on the simultaneous analysis of the irregular absolute observations and the continuous time-series deltaF, widely used for estimating the data quality. The systematic deltaF analysis allows to take into account all available information about the operation of observatory instruments (i.e., continuous records of the field variations and its modulus) in the intervals between the times of absolute observations, as compared to the traditional baseline calculation where only spot values are considered. To establish a connection with the observed spot baseline values, we introduce a function for approximate evaluation of the intermediate baseline values. An important feature of the algorithm is its quantitative estimation of the resulting data precision and thus determination of the problematic fragments in raw data. We analyze the robustness of the algorithm operation using synthetic data sets. We also compare baselines and definitive data derived by the proposed algorithm with those derived by the traditional approach using Saint Petersburg observatory data, recorded in 2015 and accepted by INTERMAGNET. It is shown that the proposed method allows to essentially improve the resulting data quality when baseline data are not good enough. The obtained results prove that the baseline variability in time might be quite rapid.[Figure not available: see fulltext.

Baseline Screening Mammography: Performance of Full-Field Digital Mammography Versus Digital Breast Tomosynthesis.

Science.gov (United States)

McDonald, Elizabeth S; McCarthy, Anne Marie; Akhtar, Amana L; Synnestvedt, Marie B; Schnall, Mitchell; Conant, Emily F

2015-11-01

Baseline mammography studies have significantly higher recall rates than mammography studies with available comparison examinations. Digital breast tomosynthesis reduces recalls when compared with digital mammographic screening alone, but many sites operate in a hybrid environment. To maximize the effect of screening digital breast tomosynthesis with limited resources, choosing which patient populations will benefit most is critical. This study evaluates digital breast tomosynthesis in the baseline screening population. Outcomes were compared for 10,728 women who underwent digital mammography screening, including 1204 (11.2%) baseline studies, and 15,571 women who underwent digital breast tomosynthesis screening, including 1859 (11.9%) baseline studies. Recall rates, cancer detection rates, and positive predictive values were calculated. Logistic regression estimated the odds ratios of recall for digital mammography versus digital breast tomosynthesis for patients undergoing baseline screening and previously screened patients, adjusted for age, race, and breast density. In the baseline subgroup, recall rates for digital mammography and digital breast tomosynthesis screening were 20.5% and 16.0%, respectively (p = 0.002); digital breast tomosynthesis screening in the baseline subgroup resulted in a 22% reduction in recall compared with digital mammography, or 45 fewer patients recalled per 1000 patients screened. Digital breast tomosynthesis screening in the previously screened patients resulted in recall reduction of 14.3% (p tomosynthesis than from digital mammography alone.

Functional Testing Protocols for Commercial Building Efficiency Baseline Modeling Software

Energy Technology Data Exchange (ETDEWEB)

Jump, David; Price, Phillip N.; Granderson, Jessica; Sohn, Michael

2013-09-06

This document describes procedures for testing and validating proprietary baseline energy modeling software accuracy in predicting energy use over the period of interest, such as a month or a year. The procedures are designed according to the methodology used for public domain baselining software in another LBNL report that was (like the present report) prepared for Pacific Gas and Electric Company: ?Commercial Building Energy Baseline Modeling Software: Performance Metrics and Method Testing with Open Source Models and Implications for Proprietary Software Testing Protocols? (referred to here as the ?Model Analysis Report?). The test procedure focuses on the quality of the software?s predictions rather than on the specific algorithms used to predict energy use. In this way the software vendor is not required to divulge or share proprietary information about how their software works, while enabling stakeholders to assess its performance.

Is CP violation observable in long baseline neutrino oscillation experiments?

International Nuclear Information System (INIS)

Tanimoto, M.

1997-01-01

We have studied CP violation originating from the phase of the neutrino-mixing matrix in the long baseline neutrino oscillation experiments. The direct measurement of CP violation is the difference of the transition probabilities between CP-conjugate channels. In those experiments, the CP-violating effect is not suppressed if the highest neutrino mass scale is taken to be 1 endash 5 eV, which is appropriate for the cosmological hot dark matter. Assuming the hierarchy for the neutrino masses, the upper bounds of CP violation have been calculated for three cases, in which mixings are constrained by the recent short baseline ones. The calculated upper bounds are larger than 10 -2 , which will be observable in the long baseline accelerator experiments. The matter effect, which is not CP invariant, has been also estimated in those experiments. copyright 1997 The American Physical Society

Integrated Baseline Review (IBR) Handbook

Science.gov (United States)

Fleming, Jon F.; Terrell, Stefanie M.

2018-01-01

The purpose of this handbook is intended to be a how-to guide to prepare for, conduct, and close-out an Integrated Baseline Review (IBR). It discusses the steps that should be considered, describes roles and responsibilities, tips for tailoring the IBR based on risk, cost, and need for management insight, and provides lessons learned from past IBRs. Appendices contain example documentation typically used in connection with an IBR. Note that these appendices are examples only, and should be tailored to meet the needs of individual projects and contracts.

Environmental Baseline File National Transportation

International Nuclear Information System (INIS)

Harris, M.

1999-01-01

This Environmental Baseline File summarizes and consolidates information related to the national-level transportation of commercial spent nuclear fuel. Topics addressed include: shipments of commercial spent nuclear fuel based on mostly truck and mostly rail shipping scenarios; transportation routing for commercial spent nuclear fuel sites and DOE sites; radionuclide inventories for various shipping container capacities; transportation routing; populations along transportation routes; urbanized area population densities; the impacts of historical, reasonably foreseeable, and general transportation; state-level food transfer factors; Federal Guidance Report No. 11 and 12 radionuclide dose conversion factors; and national average atmospheric conditions

The optimized baseline project: Reinventing environmental restoration at Hanford

International Nuclear Information System (INIS)

Goodenough, J.D.; Janaskie, M.T.; Kleinen, P.J.

1994-01-01

The U.S. Department of Energy Richland Operations Office (DOE-RL) is using a strategic planning effort (termed the Optimized Baseline Project) to develop a new approach to the Hanford Environmental Restoration program. This effort seeks to achieve a quantum leap improvement in performance through results oriented prioritization of activities. This effort was conducted in parallel with the renegotiation of the Tri-Party Agreement and provided DOE with an opportunity to propose innovative initiatives to promote cost effectiveness, accelerate progress in the Hanford Environmental Restoration Program and involve stakeholders in the decision-making process. The Optimized Baseline project is an innovative approach to program planning and decision-making in several respects. First, the process is a top down, value driven effort that responds to values held by DOE, the regulatory community and the public. Second, planning is conducted in a way that reinforces the technical management process at Richland, involves the regulatory community in substantive decisions, and includes the public. Third, the Optimized Baseline Project is being conducted as part of a sitewide Hanford initiative to reinvent Government. The planning process used for the Optimized Baseline Project has many potential applications at other sites and in other programs where there is a need to build consensus among diverse, independent groups of stakeholders and decisionmakers. The project has successfully developed and demonstrated an innovative approach to program planning that accelerates the pace of cleanup, involves the regulators as partners with DOE in priority setting, and builds public understanding and support for the program through meaningful opportunities for involvement

Baseline neurocognitive testing in sports-related concussions: the importance of a prior night's sleep.

Science.gov (United States)

McClure, D Jake; Zuckerman, Scott L; Kutscher, Scott J; Gregory, Andrew J; Solomon, Gary S

2014-02-01

The management of sports-related concussions (SRCs) utilizes serial neurocognitive assessments and self-reported symptom inventories to assess recovery and safety for return to play (RTP). Because postconcussive RTP goals include symptom resolution and a return to neurocognitive baseline levels, clinical decisions rest in part on understanding modifiers of this baseline. Several studies have reported age and sex to influence baseline neurocognitive performance, but few have assessed the potential effect of sleep. We chose to investigate the effect of reported sleep duration on baseline Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) performance and the number of patient-reported symptoms. We hypothesized that athletes receiving less sleep before baseline testing would perform worse on neurocognitive metrics and report more symptoms. Cross-sectional study; Level of evidence, 3. We retrospectively reviewed 3686 nonconcussed athletes (2371 male, 1315 female; 3305 high school, 381 college) with baseline symptom and ImPACT neurocognitive scores. Patients were stratified into 3 groups based on self-reported sleep duration the night before testing: (1) short, sleep duration on baseline ImPACT performance. A univariate ANCOVA was performed to investigate the influence of sleep on total self-reported symptoms. When controlling for age and sex as covariates, the MANCOVA revealed significant group differences on ImPACT reaction time, verbal memory, and visual memory scores but not visual-motor (processing) speed scores. An ANCOVA also revealed significant group differences in total reported symptoms. For baseline symptoms and ImPACT scores, subsequent pairwise comparisons revealed these associations to be most significant when comparing the short and intermediate sleep groups. Our results indicate that athletes sleeping fewer than 7 hours before baseline testing perform worse on 3 of 4 ImPACT scores and report more symptoms. Because SRC management and RTP

Carbon intensity of electricity generation and CDM baseline: case studies of three Chinese provinces

International Nuclear Information System (INIS)

Zhang Chi; Heller, T.C.; May, M.M.

2005-01-01

A difficult and persistent issue in the discussion of Clean Development Mechanism is estimating a carbon emissions baseline, against which tradable permits may be certified. This paper examines the proposition of adopting sectoral, as opposed to project level, baselines by conducting case studies of the electricity industry in three Chinese provinces. We find that complicated central planning, financial and institutional factors have been behind the declining trend of carbon intensity in electricity generation and its provincial variations. Government planned electricity development which incorporates many of these factors and the associated industry carbon intensity may serve as a second best baseline. However, the limitation of the baseline we examine in this study plus difficulties numerous studies have revealed in baseline setting suggests that using baselines based on counterfactuals of what would happen will in the end either miss good emission reduction opportunities, or compromise the integrity of the regime

Toward Baseline Software Anomalies in NASA Missions

Science.gov (United States)

Layman, Lucas; Zelkowitz, Marvin; Basili, Victor; Nikora, Allen P.

2012-01-01

In this fast abstract, we provide preliminary findings an analysis of 14,500 spacecraft anomalies from unmanned NASA missions. We provide some baselines for the distributions of software vs. non-software anomalies in spaceflight systems, the risk ratings of software anomalies, and the corrective actions associated with software anomalies.

Detecting CP violation in a single neutrino oscillation channel at very long baselines

International Nuclear Information System (INIS)

Latimer, D. C.; Escamilla, J.; Ernst, D. J.

2007-01-01

We propose a way of detecting CP violation in a single neutrino oscillation channel at very long baselines (on the order of several thousands of kilometers), given precise knowledge of the smallest mass-squared difference. It is shown that CP violation can be characterized by a shift in L/E of the peak oscillation in the ν e -ν μ appearance channel, both in vacuum and in matter. In fact, matter effects enhance the shift at a fixed energy. We consider the case in which sub-GeV neutrinos are measured with varying baseline and also the case of a fixed baseline. For the varied baseline, accurate knowledge of the absolute neutrino flux would not be necessary; however, neutrinos must be distinguishable from antineutrinos. For the fixed baseline, it is shown that CP violation can be distinguished if the mixing angle θ 13 were known

Pipeline integrity: ILI baseline data for QRA

Energy Technology Data Exchange (ETDEWEB)

Porter, Todd R. [Tuboscope Pipeline Services, Houston, TX (United States)]. E-mail: tporter@varco.com; Silva, Jose Augusto Pereira da [Pipeway Engenharia, Rio de Janeiro, RJ (Brazil)]. E-mail: guto@pipeway.com; Marr, James [MARR and Associates, Calgary, AB (Canada)]. E-mail: jmarr@marr-associates.com

2003-07-01

The initial phase of a pipeline integrity management program (IMP) is conducting a baseline assessment of the pipeline system and segments as part of Quantitative Risk Assessment (QRA). This gives the operator's integrity team the opportunity to identify critical areas and deficiencies in the protection, maintenance, and mitigation strategies. As a part of data gathering and integration of a wide variety of sources, in-line inspection (ILI) data is a key element. In order to move forward in the integrity program development and execution, the baseline geometry of the pipeline must be determined with accuracy and confidence. From this, all subsequent analysis and conclusions will be derived. Tuboscope Pipeline Services (TPS), in conjunction with Pipeway Engenharia of Brazil, operate ILI inertial navigation system (INS) and Caliper geometry tools, to address this integrity requirement. This INS and Caliper ILI tool data provides pipeline trajectory at centimeter level resolution and sub-metre 3D position accuracy along with internal geometry - ovality, dents, misalignment, and wrinkle/buckle characterization. Global strain can be derived from precise INS curvature measurements and departure from the initial pipeline state. Accurate pipeline elevation profile data is essential in the identification of sag/over bend sections for fluid dynamic and hydrostatic calculations. This data, along with pipeline construction, operations, direct assessment and maintenance data is integrated in LinaViewPRO{sup TM}, a pipeline data management system for decision support functions, and subsequent QRA operations. This technology provides the baseline for an informed, accurate and confident integrity management program. This paper/presentation will detail these aspects of an effective IMP, and experience will be presented, showing the benefits for liquid and gas pipeline systems. (author)

Capabilities of long-baseline experiments in the presence of a sterile neutrino

International Nuclear Information System (INIS)

Dutta, Debajyoti; Gandhi, Raj; Kayser, Boris; Masud, Mehedi; Prakash, Suprabh

2016-01-01

Assuming that there is a sterile neutrino, we ask what then is the ability of long-baseline experiments to i) establish that neutrino oscillation violates CP, ii) determine the three-neutrino mass ordering, and iii) determine which CP-violating phase or phases are the cause of any CP violation that may be observed. We find that the ability to establish CP violation and to determine the mass ordering could be very substantial. However, the effects of the sterile neutrino could be quite large, and it might prove very difficult to determine which phase is responsible for an observed CP violation. We explain why a sterile neutrino changes the long-baseline sensitivities to CP violation and to the mass ordering in the ways that it does. We note that long-baseline experiments can probe the presence of sterile neutrinos in a way that is different from, and complementary to, the probes of short-baseline experiments. We explore the question of how large sterile-active mixing angles need to be before long-baseline experiments can detect their effects, or how small they need to be before the interpretation of these experiments can safely disregard the possible existence of sterile neutrinos.

Baseline recommendations for greenhouse gas mitigation projects in the electric power sector

Energy Technology Data Exchange (ETDEWEB)

Kartha, Sivan; Lazarus, Michael [Stockholm Environment Institute/Tellus Institute, Boston, MA (United States); Bosi, Martina [International Energy Agency, Paris, 75 (France)

2004-03-01

The success of the Clean Development Mechanism (CDM) and other credit-based emission trading regimes depends on effective methodologies for quantifying a project's emissions reductions. The key methodological challenge lies in estimating project's counterfactual emission baseline, through balancing the need for accuracy, transparency, and practicality. Baseline standardisation (e.g. methodology, parameters and/or emission rate) can be a means to achieve these goals. This paper compares specific options for developing standardised baselines for the electricity sector - a natural starting point for baseline standardisation given the magnitude of the emissions reductions opportunities. The authors review fundamental assumptions that baseline studies have made with respect to estimating the generation sources avoided by CDM or other emission-reducing projects. Typically, studies have assumed that such projects affect either the operation of existing power plants (the operating margin) or the construction of new generation facilities (the build margin). The authors show that both effects are important to consider and thus recommend a combined margin approach for most projects, based on grid-specific data. They propose a three-category framework, according to projects' relative scale and environmental risk. (Author)

Study on judgement baseline for XRF on-line detection system

International Nuclear Information System (INIS)

Zhang Quanshi; Bao Min

2000-01-01

Based on the Signal Detection Theory (SDT) and the statistics principle, the choice method of judgement baseline was studied. According to the characteristics of X-ray Fluorescence (XRF) spectra in the on-line detection system, the calculation methods for the characteristic peak of the element-tagged and background were carried out. The complex judgement baseline were rationally selected after a lot of experiments and analyzing. The operating results of near one year show that it is available

Baseline Evaluations to Support Control Room Modernization at Nuclear Power Plants

Energy Technology Data Exchange (ETDEWEB)

Boring, Ronald L.; Joe, Jeffrey C.

2015-02-01

For any major control room modernization activity at a commercial nuclear power plant (NPP) in the U.S., a utility should carefully follow the four phases prescribed by the U.S. Nuclear Regulatory Commission in NUREG-0711, Human Factors Engineering Program Review Model. These four phases include Planning and Analysis, Design, Verification and Validation, and Implementation and Operation. While NUREG-0711 is a useful guideline, it is written primarily from the perspective of regulatory review, and it therefore does not provide a nuanced account of many of the steps the utility might undertake as part of control room modernization. The guideline is largely summative—intended to catalog final products—rather than formative—intended to guide the overall modernization process. In this paper, we highlight two crucial formative sub-elements of the Planning and Analysis phase specific to control room modernization that are not covered in NUREG-0711. These two sub-elements are the usability and ergonomics baseline evaluations. A baseline evaluation entails evaluating the system as-built and currently in use. The usability baseline evaluation provides key insights into operator performance using the control system currently in place. The ergonomics baseline evaluation identifies possible deficiencies in the physical configuration of the control system. Both baseline evaluations feed into the design of the replacement system and subsequent summative benchmarking activities that help ensure that control room modernization represents a successful evolution of the control system.

Baseline Evaluations to Support Control Room Modernization at Nuclear Power Plants

International Nuclear Information System (INIS)

Boring, Ronald L.; Joe, Jeffrey C.

2015-01-01

For any major control room modernization activity at a commercial nuclear power plant (NPP) in the U.S., a utility should carefully follow the four phases prescribed by the U.S. Nuclear Regulatory Commission in NUREG-0711, Human Factors Engineering Program Review Model. These four phases include Planning and Analysis, Design, Verification and Validation, and Implementation and Operation. While NUREG-0711 is a useful guideline, it is written primarily from the perspective of regulatory review, and it therefore does not provide a nuanced account of many of the steps the utility might undertake as part of control room modernization. The guideline is largely summative–intended to catalog final products–rather than formative–intended to guide the overall modernization process. In this paper, we highlight two crucial formative sub-elements of the Planning and Analysis phase specific to control room modernization that are not covered in NUREG-0711. These two sub-elements are the usability and ergonomics baseline evaluations. A baseline evaluation entails evaluating the system as-built and currently in use. The usability baseline evaluation provides key insights into operator performance using the control system currently in place. The ergonomics baseline evaluation identifies possible deficiencies in the physical configuration of the control system. Both baseline evaluations feed into the design of the replacement system and subsequent summative benchmarking activities that help ensure that control room modernization represents a successful evolution of the control system.

Effect of Enamel Caries Lesion Baseline Severity on Fluoride Dose-Response

Directory of Open Access Journals (Sweden)

Frank Lippert

2017-01-01

Full Text Available This study aimed to investigate the effect of enamel caries lesion baseline severity on fluoride dose-response under pH cycling conditions. Early caries lesions were created in human enamel specimens at four different severities (8, 16, 24, and 36 h. Lesions were allocated to treatment groups (0, 83, and 367 ppm fluoride as sodium fluoride based on Vickers surface microhardness (VHN and pH cycled for 5 d. The cycling model comprised 3 × 1 min fluoride treatments sandwiched between 2 × 60 min demineralization challenges with specimens stored in artificial saliva in between. VHN was measured again and changes versus lesion baseline were calculated (ΔVHN. Data were analyzed using two-way ANOVA (p<0.05. Increased demineralization times led to increased surface softening. The lesion severity×fluoride concentration interaction was significant (p<0.001. Fluoride dose-response was observed in all groups. Lesions initially demineralized for 16 and 8 h showed similar overall rehardening (ΔVHN and more than 24 and 36 h lesions, which were similar. The 8 h lesions showed the greatest fluoride response differential (367 versus 0 ppm F which diminished with increasing lesion baseline severity. The extent of rehardening as a result of the 0 ppm F treatment increased with increasing lesion baseline severity, whereas it decreased for the fluoride treatments. In conclusion, lesion baseline severity impacts the extent of the fluoride dose-response.

GNSS Single Frequency, Single Epoch Reliable Attitude Determination Method with Baseline Vector Constraint

Directory of Open Access Journals (Sweden)

Ang Gong

2015-12-01

Full Text Available For Global Navigation Satellite System (GNSS single frequency, single epoch attitude determination, this paper proposes a new reliable method with baseline vector constraint. First, prior knowledge of baseline length, heading, and pitch obtained from other navigation equipment or sensors are used to reconstruct objective function rigorously. Then, searching strategy is improved. It substitutes gradually Enlarged ellipsoidal search space for non-ellipsoidal search space to ensure correct ambiguity candidates are within it and make the searching process directly be carried out by least squares ambiguity decorrelation algorithm (LAMBDA method. For all vector candidates, some ones are further eliminated by derived approximate inequality, which accelerates the searching process. Experimental results show that compared to traditional method with only baseline length constraint, this new method can utilize a priori baseline three-dimensional knowledge to fix ambiguity reliably and achieve a high success rate. Experimental tests also verify it is not very sensitive to baseline vector error and can perform robustly when angular error is not great.

Site Outcomes Baseline Multi Year Work Plan Volume 1, River Corridor Restoration Baseline

International Nuclear Information System (INIS)

Wintczak, T.M.

2001-01-01

The River Corridor Restoration volume is a compilation of Hanford Site scope, which excludes the approximately 194 km 2 Central Plateau. The River Corridor scope is currently contractually assigned to Fluor Hanford, Bechtel Hanford, inc., DynCorp, and Pacific Northwest National Laboratory, and others. The purpose of this project specification is to provide an overall scoping document for the River Corridor Restoration volume, and to provide a link with the overall Hanford Site River Corridor scope. Additionally, this specification provides an integrated and consolidated source of information for the various scopes, by current contract, for the River Corridor Restoration Baseline. It identifies the vision, mission, and goals, as well as the operational history of the Hanford Site, along with environmental setting and hazards

Classification of baseline toxicants for QSAR predictions to replace fish acute toxicity studies.

Science.gov (United States)

Nendza, Monika; Müller, Martin; Wenzel, Andrea

2017-03-22

Fish acute toxicity studies are required for environmental hazard and risk assessment of chemicals by national and international legislations such as REACH, the regulations of plant protection products and biocidal products, or the GHS (globally harmonised system) for classification and labelling of chemicals. Alternative methods like QSARs (quantitative structure-activity relationships) can replace many ecotoxicity tests. However, complete substitution of in vivo animal tests by in silico methods may not be realistic. For the so-called baseline toxicants, it is possible to predict the fish acute toxicity with sufficient accuracy from log K ow and, hence, valid QSARs can replace in vivo testing. In contrast, excess toxicants and chemicals not reliably classified as baseline toxicants require further in silico, in vitro or in vivo assessments. Thus, the critical task is to discriminate between baseline and excess toxicants. For fish acute toxicity, we derived a scheme based on structural alerts and physicochemical property thresholds to classify chemicals as either baseline toxicants (=predictable by QSARs) or as potential excess toxicants (=not predictable by baseline QSARs). The step-wise approach identifies baseline toxicants (true negatives) in a precautionary way to avoid false negative predictions. Therefore, a certain fraction of false positives can be tolerated, i.e. baseline toxicants without specific effects that may be tested instead of predicted. Application of the classification scheme to a new heterogeneous dataset for diverse fish species results in 40% baseline toxicants, 24% excess toxicants and 36% compounds not classified. Thus, we can conclude that replacing about half of the fish acute toxicity tests by QSAR predictions is realistic to be achieved in the short-term. The long-term goals are classification criteria also for further groups of toxicants and to replace as many in vivo fish acute toxicity tests as possible with valid QSAR

Baseline frontostriatal-limbic connectivity predicts reward-based memory formation.

Science.gov (United States)

Hamann, Janne M; Dayan, Eran; Hummel, Friedhelm C; Cohen, Leonardo G

2014-12-01

Reward mediates the acquisition and long-term retention of procedural skills in humans. Yet, learning under rewarded conditions is highly variable across individuals and the mechanisms that determine interindividual variability in rewarded learning are not known. We postulated that baseline functional connectivity in a large-scale frontostriatal-limbic network could predict subsequent interindividual variability in rewarded learning. Resting-state functional MRI was acquired in two groups of subjects (n = 30) who then trained on a visuomotor procedural learning task with or without reward feedback. We then tested whether baseline functional connectivity within the frontostriatal-limbic network predicted memory strength measured immediately, 24 h and 1 month after training in both groups. We found that connectivity in the frontostriatal-limbic network predicted interindividual variability in the rewarded but not in the unrewarded learning group. Prediction was strongest for long-term memory. Similar links between connectivity and reward-based memory were absent in two control networks, a fronto-parieto-temporal language network and the dorsal attention network. The results indicate that baseline functional connectivity within the frontostriatal-limbic network successfully predicts long-term retention of rewarded learning. © 2014 Wiley Periodicals, Inc.

Localizing gravitational wave sources with single-baseline atom interferometers

Science.gov (United States)

Graham, Peter W.; Jung, Sunghoon

2018-02-01

Localizing sources on the sky is crucial for realizing the full potential of gravitational waves for astronomy, astrophysics, and cosmology. We show that the midfrequency band, roughly 0.03 to 10 Hz, has significant potential for angular localization. The angular location is measured through the changing Doppler shift as the detector orbits the Sun. This band maximizes the effect since these are the highest frequencies in which sources live for several months. Atom interferometer detectors can observe in the midfrequency band, and even with just a single baseline they can exploit this effect for sensitive angular localization. The single-baseline orbits around the Earth and the Sun, causing it to reorient and change position significantly during the lifetime of the source, and making it similar to having multiple baselines/detectors. For example, atomic detectors could predict the location of upcoming black hole or neutron star merger events with sufficient accuracy to allow optical and other electromagnetic telescopes to observe these events simultaneously. Thus, midband atomic detectors are complementary to other gravitational wave detectors and will help complete the observation of a broad range of the gravitational spectrum.

Leveraging probabilistic peak detection to estimate baseline drift in complex chromatographic samples

NARCIS (Netherlands)

Lopatka, M.; Barcaru, A.; Sjerps, M.J.; Vivó-Truyols, G.

2016-01-01

Accurate analysis of chromatographic data often requires the removal of baseline drift. A frequently employed strategy strives to determine asymmetric weights in order to fit a baseline model by regression. Unfortunately, chromatograms characterized by a very high peak saturation pose a significant

Socioeconomic position and participation in baseline and follow-up visits

DEFF Research Database (Denmark)

Bender, Anne M; Jørgensen, Torben; Hansen, Bodil Helbech

2012-01-01

Background:The aim of this paper was to identify the extent of socioeconomic inequality in participation at baseline and follow-up visits.Design:The Inter99 study is a randomized intervention with the aim of investigating the effects of an individualized lifestyle consultation on ischaemic heart ...... inequality in participation at baseline and follow-up visits. Effort should be made to increase participation in individualized lifestyle interventions among persons of low socioeconomic position. Otherwise, the consequence may be increased socioeconomic inequality in IHD....

Baseline study of radiology services for the purpose of PACS evaluation

International Nuclear Information System (INIS)

Mun, S.K.; Benson, H.; Welsh, C.; Elliott, L.P.; Davros, W.

1988-01-01

This paper reports initial results of a radiology department baseline study of workload and data flow patterns for image generation, film library activities, report generation reporting activities at the film alternators and report transcription and validation. The authors analyze the film based operations prior to full implementation of the image management and communication system. The baseline study topics are examined

Baseline LAW Glass Formulation Testing

International Nuclear Information System (INIS)

Kruger, Albert A.; Mooers, Cavin; Bazemore, Gina; Pegg, Ian L.; Hight, Kenneth; Lai, Shan Tao; Buechele, Andrew; Rielley, Elizabeth; Gan, Hao; Muller, Isabelle S.; Cecil, Richard

2013-01-01

The major objective of the baseline glass formulation work was to develop and select glass formulations that are compliant with contractual and processing requirements for each of the LAW waste streams. Other objectives of the work included preparation and characterization of glasses with respect to the properties of interest, optimization of sulfate loading in the glasses, evaluation of ability to achieve waste loading limits, testing to demonstrate compatibility of glass melts with melter materials of construction, development of glass formulations to support ILAW qualification activities, and identification of glass formulation issues with respect to contract specifications and processing requirements

Baseline atmospheric program Australia 1993

International Nuclear Information System (INIS)

Francey, R.J.; Dick, A.L.; Derek, N.

1996-01-01

This publication reports activities, program summaries and data from the Cape Grim Baseline Air Pollution Station in Tasmania, during the calendar year 1993. These activities represent Australia's main contribution to the Background Air Pollution Monitoring Network (BAPMoN), part of the World Meteorological Organization's Global Atmosphere Watch (GAW). The report includes 5 research reports covering trace gas sampling, ozone and radon interdependence, analysis of atmospheric dimethylsulfide and carbon-disulfide, sampling of trace gas composition of the troposphere, and sulfur aerosol/CCN relationship in marine air. Summaries of program reports for the calendar year 1993 are also included. Tabs., figs., refs

El ALBA y los “anti”. Un proyecto de integración alternativo latinoamericano

Directory of Open Access Journals (Sweden)

Adolfo A. Abadía

2014-12-01

Full Text Available Reseña del libro:Bagley, B. M. y Defort M. (Eds. (2014. ¿La hegemonía norteamericana en declive? El desafío del ALBA y la nueva integración latinoamericana del siglo XXI. ColecciónEl sur es cielo roto. Cali, Colombia: Facultad de Derecho y Ciencias Sociales,Universidad Icesi. 640 pp.

Las cortes de Cádiz

Directory of Open Access Journals (Sweden)

Abelardo Forero Benavides

1966-07-01

Full Text Available Esta es una página gloriosa e infecunda de la historia de España. La mayor parte de su territorio está ocupado por las tropas francesas. Se adelanta una guerrilla cruel en contra del usurpador. El rey Fernando continúa cautivo en Valancay. La resistencia tenaz y formidable ha roto todos los cálculos de Bonaparte.

MERI: an ultra-long-baseline Moon-Earth radio interferometer.

Science.gov (United States)

Burns, J. O.

Radiofrequency aperture synthesis, pioneered by Ryle and his colleagues at Cambridge in the 1960's, has evolved to ever longer baselines and larger arrays in recent years. The limiting resolution at a given frequency for modern ground-based very-long-baseline interferometry is simply determined by the physical diameter of the Earth. A second-generation, totally space-based VLB network was proposed recently by a group at the Naval Research Laboratory. The next logical extension of space-based VLBI would be a station or stations on the Moon. The Moon could serve as an outpost or even the primary correlator station for an extended array of space-based antennas.

Wide-Baseline Stereo-Based Obstacle Mapping for Unmanned Surface Vehicles

Science.gov (United States)

Mou, Xiaozheng; Wang, Han

2018-01-01

This paper proposes a wide-baseline stereo-based static obstacle mapping approach for unmanned surface vehicles (USVs). The proposed approach eliminates the complicated calibration work and the bulky rig in our previous binocular stereo system, and raises the ranging ability from 500 to 1000 m with a even larger baseline obtained from the motion of USVs. Integrating a monocular camera with GPS and compass information in this proposed system, the world locations of the detected static obstacles are reconstructed while the USV is traveling, and an obstacle map is then built. To achieve more accurate and robust performance, multiple pairs of frames are leveraged to synthesize the final reconstruction results in a weighting model. Experimental results based on our own dataset demonstrate the high efficiency of our system. To the best of our knowledge, we are the first to address the task of wide-baseline stereo-based obstacle mapping in a maritime environment. PMID:29617293

2017 Annual Technology Baseline

Energy Technology Data Exchange (ETDEWEB)

Cole, Wesley J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hand, M. M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Eberle, Annika [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Beiter, Philipp C [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kurup, Parthiv [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Turchi, Craig S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Feldman, David J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Margolis, Robert M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Augustine, Chad R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Maness, Michael [Formerly NREL; O' Connor, Patrick [Oak Ridge National Laboratory

2018-03-26

Consistent cost and performance data for various electricity generation technologies can be difficult to find and may change frequently for certain technologies. With the Annual Technology Baseline (ATB), the National Renewable Energy Laboratory annually provides an organized and centralized set of such cost and performance data. The ATB uses the best information from the Department of Energy national laboratories' renewable energy analysts as well as information from the Energy Information Administration for fuel-based technologies. The ATB has been reviewed by experts and it includes the following electricity generation technologies: land-based wind, offshore wind, utility-scale solar photovoltaics (PV), commercial-scale solar PV, residential-scale solar PV, concentrating solar power, geothermal power, hydropower, coal, natural gas, nuclear, and conventional biopower. This webinar presentation introduces the 2017 ATB.

Baseline Vascular Cognitive Impairment Predicts the Course of Apathetic Symptoms After Stroke: The CASPER Study.

Science.gov (United States)

Douven, Elles; Köhler, Sebastian; Schievink, Syenna H J; van Oostenbrugge, Robert J; Staals, Julie; Verhey, Frans R J; Aalten, Pauline

2018-03-01

To examine the influence of vascular cognitive impairment (VCI) on the course of poststroke depression (PSD) and poststroke apathy (PSA). Included were 250 stroke patients who underwent neuropsychological and neuropsychiatric assessment 3 months after stroke (baseline) and at a 6- and 12-month follow-up after baseline. Linear mixed models tested the influence of VCI in at least one cognitive domain (any VCI) or multidomain VCI (VCI in multiple cognitive domains) at baseline and domain-specific VCI at baseline on levels of depression and apathy over time, with random effects for intercept and slope. Almost half of the patients showed any VCI at baseline, and any VCI was associated with increasing apathy levels from baseline to the 12-month follow-up. Patients with multidomain VCI had higher apathy scores at the 6- and 12-month follow-up compared with patients with VCI in a single cognitive domain. Domain-specific analyses showed that impaired executive function and slowed information processing speed went together with increasing apathy levels from baseline to 6- and 12-month follow-up. None of the cognitive variables predicted the course of depressive symptoms. Baseline VCI is associated with increasing apathy levels from baseline to the chronic stroke phase, whereas no association was found between baseline VCI and the course of depressive symptoms. Health professionals should be aware that apathy might be absent early after stroke but may evolve over time in patients with VCI. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Twenty-month follow-up of occlusal caries lesions deemed questionable at baseline

DEFF Research Database (Denmark)

Makhija, Sonia K; Gilbert, Gregg H; Funkhouser, Ellen

2014-01-01

-three clinicians from The National Dental Practice-Based Research Network participated in this study, recording lesion characteristics at baseline and lesion status at 20 months. RESULTS: At baseline, 1,341 QOC lesions were examined; the treatment that was planned for 1,033 of those at baseline was monitoring...... (oral hygiene instruction, applying or prescribing fluoride or varnish, or both), and the remaining 308 received a sealant (n = 192) or invasive therapy (n = 116). At the 20-month visit, clinicians continued to monitor 927 (90 percent) of the 1,033 monitored lesions. Clinicians decided to seal 61 (6...

40 CFR 80.245 - How does a small refiner apply for a sulfur baseline?

Science.gov (United States)

2010-07-01

... sulfur baseline? 80.245 Section 80.245 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Provisions § 80.245 How does a small refiner apply for a sulfur baseline? (a) Any refiner seeking small refiner status must apply for a refinery sulfur baseline by the deadline under § 80.235 for each of the...

The steroids for corneal ulcers trial: study design and baseline characteristics.

Science.gov (United States)

Srinivasan, Muthiah; Mascarenhas, Jeena; Rajaraman, Revathi; Ravindran, Meenakshi; Lalitha, Prajna; Glidden, David V; Ray, Kathryn J; Hong, Kevin C; Oldenburg, Catherine E; Lee, Salena M; Zegans, Michael E; McLeod, Stephen D; Lietman, Thomas M; Acharya, Nisha R

2012-02-01

To provide comprehensive trial methods and baseline data for the Steroids for Corneal Ulcers Trial and to present epidemiological characteristics such as risk factors, causative organisms, and ulcer severity. Baseline data from a 1:1 randomized, placebo-controlled, double-masked clinical trial comparing prednisolone phosphate, 1%, with placebo as adjunctive therapy for the treatment of bacterial corneal ulcers. Eligible patients had a culture-positive bacterial corneal ulcer and had been taking moxifloxacin for 48 hours. The primary outcome for the trial is best spectacle-corrected visual acuity at 3 months from enrollment. This report provides comprehensive baseline data, including best spectacle-corrected visual acuity, infiltrate size, microbiological results, and patient demographics, for patients enrolled in the trial. Of 500 patients enrolled, 97% were in India. Two hundred twenty patients (44%) were agricultural workers. Median baseline visual acuity was 0.84 logMAR (Snellen, 20/125) (interquartile range, 0.36-1.7; Snellen, 20/50 to counting fingers). Baseline visual acuity was not significantly different between the United States and India. Ulcers in India had larger infiltrate/scar sizes (P = .04) and deeper infiltrates (P = .04) and were more likely to be localized centrally (P = .002) than ulcers enrolled in the United States. Gram-positive bacteria were the most common organisms isolated from the ulcers (n = 366, 72%). The Steroids for Corneal Ulcers Trial will compare the use of a topical corticosteroid with placebo as adjunctive therapy for bacterial corneal ulcers. Patients enrolled in this trial had diverse ulcer severity and on average significantly reduced visual acuity at presentation. clinicaltrials.gov Identifier: NCT00324168.

77 FR 21760 - Atmos Energy Colorado/Kansas Division; Notice of Baseline Filing

Science.gov (United States)

2012-04-11

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR12-19-000] Atmos Energy Colorado/Kansas Division; Notice of Baseline Filing Take notice that on March 30, 2012, Atmos Energy Colorado/Kansas Division (Atmos) submitted a baseline filing of their Statement of Operating Conditions for...

Forecasting Sensorimotor Adaptability from Baseline Inter-Trial Correlations

Science.gov (United States)

Beaton, K. H.; Bloomberg, J. J.

2016-01-01

One of the greatest challenges for sensorimotor adaptation to the spaceflight environment is the large variability in symptoms, and corresponding functional impairments, from one crewmember to the next. This renders preflight training and countermeasure development difficult, as a "one-size-fits-all" approach is inappropriate. Therefore, it would be highly advantageous to know ahead of time which crewmembers might have more difficulty adjusting to the novel g-levels inherent to spaceflight. This information could guide individually customized countermeasures, which would enable more efficient use of crew time and provide better outcomes. The principal aim of this work is to look for baseline performance metrics that relate to locomotor adaptability. We propose a novel hypothesis that considers baseline inter-trial correlations, the trial-to-trial fluctuations ("noise") in motor performance, as a predictor of individual adaptive capabilities.

Baseline Neurocognitive Test Results In Non-concussed Athletes: Does Sleep Matter?

OpenAIRE

McClure, D. Jake; Zuckerman, Scott L.; Kutscher, Scott J.; Gregory, Andrew; Solomon, Gary S.

2013-01-01

Objectives: When managing sport-related concussions (SRC), sports medicine physicians utilize serial neurocognitive assessments and self-reported symptom inventories when evaluating athlete recovery and safety for returning to play (RTP). Since post-concussive RTP goals include symptom resolution and return to neurocognitive baseline, clinical decisions rest on an understanding of modifiers of baseline performance. Several studies have reported the influence of age, gender and sport on baseli...

CryoSat Ice Processor: High-Level Overview of Baseline-C Data and Quality-Control

Science.gov (United States)

Mannan, R.; Webb, E.; Hall, A.; Bouffard, J.; Femenias, P.; Parrinello, T.; Bouffard, J.; Brockley, D.; Baker, S.; Scagliola, M.; Urien, S.

2016-08-01

Since April 2015, the CryoSat ice products have been generated with the new Baseline-C Instrument Processing Facilities (IPFs). This represents a major upgrade to the CryoSat ice IPFs and is the baseline for the second CryoSat Reprocessing Campaign. Baseline- C introduces major evolutions with respect to Baseline- B, most notably the release of freeboard data within the L2 SAR products, following optimisation of the SAR retracker. Additional L2 improvements include a new Arctic Mean Sea Surface (MSS) in SAR; a new tuneable land ice retracker in LRM; and a new Digital Elevation Model (DEM) in SARIn. At L1B new attitude fields have been introduced and existing datation and range biases reduced. This paper provides a high level overview of the changes and evolutions implemented at Baseline-C in order to improve CryoSat L1B and L2 data characteristics and exploitation over polar regions. An overview of the main Quality Control (QC) activities performed on operational Baseline-C products is also presented.

Effect of surface stress states on the corrosion behavior of alloy 690

Energy Technology Data Exchange (ETDEWEB)

Kim, Myung Mo; Shim, Hee Sang; Seo, Myung Ji; Hur, Do Haeng [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-05-15

The test environment simulated the primary water chemistry in PWRs. Dissolved oxygen (DO), dissolved hydrogen (DH), pH and conductivity were monitored at room temperature using sensors manufactured by Orbisphere and Mettler Toledo. The temperature and pressure were maintained at 330 .deg. C and 150 bars during the corrosion test. The condition of the test solution was lithium (LiOH) 2 ppm and boron (H3BO4) 1,200 ppm, DH 35 cc/kg (STP) and less than 5 ppb DO. The flow rate of the loop system was 3.8 L/hour. Corrosion tests were conducted for 500 hours. The corrosion release rate was evaluated by a gravimetric analysis method using a two-step alkaline permanganate-ammonium citrate (AP/AC) descaling process. Compressive residual stress is induced by shot peening treatment but its value reveals some different trend between the shot peening intensity on the surface of Alloy 690 TT. A higher shot peening intensity causes a reduction in the corrosion rate and it is considered that the compressive residual stress beneath the surface layer suppresses the metal ion transfer in an alloy matrix.

Astrometry of 25 Southern Hemisphere Radio Sources From A VLBI Short-Baseline Survey

National Research Council Canada - National Science Library

Fey, Alan

2004-01-01

.... These positions are derived from Mark III Very Long Baseline Interferometry observations made between 2003 September and 2004 May on the intra-Australia baseline connecting Hobart, Tasmania and Parkes, New South Wales...

Baseline and cognition activated brain SPECT imaging in depression

International Nuclear Information System (INIS)

Zhao Jinhua; Lin Xiangtong; Jiang Kaida; Liu Yongchang; Xu Lianqin

1998-01-01

Purpose: To evaluate the regional cerebral blood flow (rCBF) abnormalities through the semiquantitative analysis of the baseline and cognition activated rCBF imaging in unmedicated depressed patients. Methods: 27 depressed patients unmedicated by anti-depressants were enrolled. The diagnosis (depression of moderate degree with somatization) was confirmed by the ICD-10 criteria. 15 age matched normal controls were studied under identical conditions. Baseline and cognition activated 99m Tc-ECD SPECT were performed on 21 of the 27 patients with depression and 13 of the 15 normal controls. Baseline 99m Tc-ECD SPECT alone were performed on the rest 6 patients with depression and 2 normal controls. The cognitive activation is achieved by Wisconsin Card Sorting Test (WCST). 1110 MBq of 99m Tc-ECD was administered by intravenous bolus injection 5 minutes after the onset of the WCST. Semi-quantitative analysis was conducted with the 7th, 8th, 9th, 10th, 11th slices of the transaxial imaging. rCBF ratios of every ROI were calculated using the average tissue activity in the region divided by the maximum activity in the cerebellum. Results: 1) The baseline rCBF of left frontal (0.720) and left temporal lobe (0.720) were decreased significantly in depressed patients comparing with those of the control subjects. 2) The activated rCBF of left frontal lobe (0.719) and left temporal lobe (0.690), left parietal lobe (0.701) were decreased evidently than those of the controls. Conclusions: 1) Hypoperfusions of left frontal and left temporal cortexes were identified in patients with depression. 2) The hypoperfusion of left frontal and left temporal cortexes may be the cause of cognition disorder and depressed mood in patients with depression. 3) Cognition activated brain perfusion imaging is helpful for making a more accurate diagnosis of depression

How to deal with cost differences at baseline

NARCIS (Netherlands)

Van Asselt, Antoinette D.I.; Van Mastrigt, Ghislaine A.P.G.; Dirksen, Carmen D.; Arntz, Arnoud; Severens, Johan L.; Kessels, Alfons G.H.

BACKGROUND: To our knowledge, adjustment for baseline imbalances in costs has never been performed in trial-based cost-effectiveness analyses. METHODS: We used data from a clinical trial performed in the Netherlands comparing two outpatient psychotherapies: schema-focused therapy (SFT) versus

High baseline activity in inferior temporal cortex improves neural and behavioral discriminability during visual categorization

Science.gov (United States)

Emadi, Nazli; Rajimehr, Reza; Esteky, Hossein

2014-01-01

Spontaneous firing is a ubiquitous property of neural activity in the brain. Recent literature suggests that this baseline activity plays a key role in perception. However, it is not known how the baseline activity contributes to neural coding and behavior. Here, by recording from the single neurons in the inferior temporal cortex of monkeys performing a visual categorization task, we thoroughly explored the relationship between baseline activity, the evoked response, and behavior. Specifically we found that a low-frequency (baseline activity. This enhancement of the baseline activity was then followed by an increase in the neural selectivity and the response reliability and eventually a higher behavioral performance. PMID:25404900

Choice of baseline climate data impacts projected species' responses to climate change.

Science.gov (United States)

Baker, David J; Hartley, Andrew J; Butchart, Stuart H M; Willis, Stephen G

2016-07-01

Climate data created from historic climate observations are integral to most assessments of potential climate change impacts, and frequently comprise the baseline period used to infer species-climate relationships. They are often also central to downscaling coarse resolution climate simulations from General Circulation Models (GCMs) to project future climate scenarios at ecologically relevant spatial scales. Uncertainty in these baseline data can be large, particularly where weather observations are sparse and climate dynamics are complex (e.g. over mountainous or coastal regions). Yet, importantly, this uncertainty is almost universally overlooked when assessing potential responses of species to climate change. Here, we assessed the importance of historic baseline climate uncertainty for projections of species' responses to future climate change. We built species distribution models (SDMs) for 895 African bird species of conservation concern, using six different climate baselines. We projected these models to two future periods (2040-2069, 2070-2099), using downscaled climate projections, and calculated species turnover and changes in species-specific climate suitability. We found that the choice of baseline climate data constituted an important source of uncertainty in projections of both species turnover and species-specific climate suitability, often comparable with, or more important than, uncertainty arising from the choice of GCM. Importantly, the relative contribution of these factors to projection uncertainty varied spatially. Moreover, when projecting SDMs to sites of biodiversity importance (Important Bird and Biodiversity Areas), these uncertainties altered site-level impacts, which could affect conservation prioritization. Our results highlight that projections of species' responses to climate change are sensitive to uncertainty in the baseline climatology. We recommend that this should be considered routinely in such analyses. © 2016 John Wiley

The impact of GPS receiver modifications and ionospheric activity on Swarm baseline determination

Science.gov (United States)

Mao, X.; Visser, P. N. A. M.; van den IJssel, J.

2018-05-01

The European Space Agency (ESA) Swarm mission is a satellite constellation launched on 22 November 2013 aiming at observing the Earth geomagnetic field and its temporal variations. The three identical satellites are equipped with high-precision dual-frequency Global Positioning System (GPS) receivers, which make the constellation an ideal test bed for baseline determination. From October 2014 to August 2016, a number of GPS receiver modifications and a new GPS Receiver Independent Exchange Format (RINEX) converter were implemented. Moreover, the on-board GPS receiver performance has been influenced by the ionospheric scintillations. The impact of these factors is assessed for baseline determination of the pendulum formation flying Swarm-A and -C satellites. In total 30 months of data - from 15 July 2014 to the end of 2016 - is analyzed. The assessment includes analysis of observation residuals, success rate of GPS carrier phase ambiguity fixing, a consistency check between the so-called kinematic and reduced-dynamic baseline solution, and validations of orbits by comparing with Satellite Laser Ranging (SLR) observations. External baseline solutions from The German Space Operations Center (GSOC) and Astronomisches Institut - Universität Bern (AIUB) are also included in the comparison. Results indicate that the GPS receiver modifications and RINEX converter changes are effective to improve the baseline determination. This research eventually shows a consistency level of 9.3/4.9/3.0 mm between kinematic and reduced-dynamic baselines in the radial/along-track/cross-track directions. On average 98.3% of the epochs have kinematic solutions. Consistency between TU Delft and external reduced-dynamic baseline solutions is at a level of 1 mm level in all directions.

Addendum to the 2015 Eastern Interconnect Baselining and Analysis Report

Energy Technology Data Exchange (ETDEWEB)

Amidan, Brett G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Follum, James D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2016-06-30

This report serves as an addendum to the report 2015 Eastern Interconnect Baselining and Analysis Report (Amidan, Follum, and Freeman, 2015). This addendum report investigates the following: the impact of shorter record lengths and of adding a daily regularization term to the date/time models for angle pair measurements, additional development of a method to monitor the trend in phase angle pairs, the effect of changing the length of time to determine a baseline, when calculating atypical events, and a comparison between quantitatively discovered atypical events and actual events.

Studies into the Effects of Surface Roughness on Spatial Eddy-Current Data from Nickel-Based Engine Alloys

International Nuclear Information System (INIS)

Johnson, M.J.; Nakagawa, N.; Wendt, S.E.; Hentscher, S.R.; Nelson, D.L.; Buhr, K.T.; Kilbugh, B.A.; Raithel, D.C.

2005-01-01

Eddy-current scans have been carried out on two Inconel-718 specimens following the application of various levels of shot peening and heat treatments. The conventional analysis of roughened or shot peened surfaces looks at multi-frequency impedance measurements and interprets the data as a change in conductivity or liftoff. An approach involving the statistical analysis of scanned eddy-current impedance data is suggested as an alternative that may provide a more sensitive way of determining the treatment history of a component. It is possible that an analysis of these statistical distributions in spatial eddy-current data could be used to determine the level of remaining residual stress in engine components

Large scale, highly dense nanoholes on metal surfaces by underwater laser assisted hydrogen etching near nanocrystalline boundary

Energy Technology Data Exchange (ETDEWEB)

Lin Dong; Zhang, Martin Yi; Ye Chang; Liu Zhikun; Liu, C. Richard [School of Industrial Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47906 (United States); Cheng, Gary J., E-mail: gjcheng@purdue.edu [School of Industrial Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47906 (United States)

2012-03-01

A new method to generate large scale and highly dense nanoholes is presented in this paper. By the pulsed laser irradiation under water, the hydrogen etching is introduced to form high density nanoholes on the surfaces of AISI 4140 steel and Ti. In order to achieve higher nanohole density, laser shock peening (LSP) followed by recrystallization is used for grain refinement. It is found that the nanohole density does not increase until recrystallization of the substructures after laser shock peening. The mechanism of nanohole generation is studied in detail. This method can be also applied to generate nanoholes on other materials with hydrogen etching effect.

Large scale, highly dense nanoholes on metal surfaces by underwater laser assisted hydrogen etching near nanocrystalline boundary

International Nuclear Information System (INIS)

Lin Dong; Zhang, Martin Yi; Ye Chang; Liu Zhikun; Liu, C. Richard; Cheng, Gary J.

2012-01-01

A new method to generate large scale and highly dense nanoholes is presented in this paper. By the pulsed laser irradiation under water, the hydrogen etching is introduced to form high density nanoholes on the surfaces of AISI 4140 steel and Ti. In order to achieve higher nanohole density, laser shock peening (LSP) followed by recrystallization is used for grain refinement. It is found that the nanohole density does not increase until recrystallization of the substructures after laser shock peening. The mechanism of nanohole generation is studied in detail. This method can be also applied to generate nanoholes on other materials with hydrogen etching effect.

A Mean-Shift-Based Feature Descriptor for Wide Baseline Stereo Matching

Directory of Open Access Journals (Sweden)

Yiwen Dou

2015-01-01

Full Text Available We propose a novel Mean-Shift-based building approach in wide baseline. Initially, scale-invariance feature transform (SIFT approach is used to extract relatively stable feature points. As to each matching SIFT feature point, it needs a reasonable neighborhood range so as to choose feature points set. Subsequently, in view of selecting repeatable and high robust feature points, Mean-Shift controls corresponding feature scale. At last, our approach is employed to depth image acquirement in wide baseline and Graph Cut algorithm optimizes disparity information. Compared with the existing methods such as SIFT, speeded up robust feature (SURF, and normalized cross-correlation (NCC, the presented approach has the advantages of higher robustness and accuracy rate. Experimental results on low resolution image and weak feature description in wide baseline confirm the validity of our approach.

Profile of NASA software engineering: Lessons learned from building the baseline

Science.gov (United States)

Hall, Dana; Mcgarry, Frank

1993-01-01

It is critically important in any improvement activity to first understand the organization's current status, strengths, and weaknesses and, only after that understanding is achieved, examine and implement promising improvements. This fundamental rule is certainly true for an organization seeking to further its software viability and effectiveness. This paper addresses the role of the organizational process baseline in a software improvement effort and the lessons we learned assembling such an understanding for NASA overall and for the NASA Goddard Space Flight Center in particular. We discuss important, core data that must be captured and contrast that with our experience in actually finding such information. Our baselining efforts have evolved into a set of data gathering, analysis, and crosschecking techniques and information presentation formats that may prove useful to others seeking to establish similar baselines for their organization.

Wide baseline stereo matching based on double topological relationship consistency

Science.gov (United States)

Zou, Xiaohong; Liu, Bin; Song, Xiaoxue; Liu, Yang

2009-07-01

Stereo matching is one of the most important branches in computer vision. In this paper, an algorithm is proposed for wide-baseline stereo vision matching. Here, a novel scheme is presented called double topological relationship consistency (DCTR). The combination of double topological configuration includes the consistency of first topological relationship (CFTR) and the consistency of second topological relationship (CSTR). It not only sets up a more advanced model on matching, but discards mismatches by iteratively computing the fitness of the feature matches and overcomes many problems of traditional methods depending on the powerful invariance to changes in the scale, rotation or illumination across large view changes and even occlusions. Experimental examples are shown where the two cameras have been located in very different orientations. Also, epipolar geometry can be recovered using RANSAC by far the most widely method adopted possibly. By the method, we can obtain correspondences with high precision on wide baseline matching problems. Finally, the effectiveness and reliability of this method are demonstrated in wide-baseline experiments on the image pairs.

Very long baseline interferometry applied to polar motion, relativity, and geodesy. Ph.D. thesis

International Nuclear Information System (INIS)

Ma, C.

1978-01-01

The causes and effects of diurnal polar motion are described. An algorithm was developed for modeling the effects on very long baseline interferometry observables. A selection was made between two three-station networks for monitoring polar motion. The effects of scheduling and the number of sources observed on estimated baseline errors are discussed. New hardware and software techniques in very long baseline interferometry are described

Earth matter effects at very long baselines and the neutrino mass hierarchy

International Nuclear Information System (INIS)

Gandhi, Raj; Ghoshal, Pomita; Goswami, Srubabati; Mehta, Poonam; Sankar, S. Uma

2006-01-01

We study matter effects which arise in the muon neutrino oscillation and survival probabilities relevant to atmospheric neutrino and very long baseline (>4000 Km) beam experiments. The interrelations between the three probabilities P μe , P μτ , and P μμ are examined. It is shown that large and observable sensitivity to the neutrino mass hierarchy can be present in P μμ and P μτ . We emphasize that at baselines >7000 Km, matter effects in P μτ are important under certain conditions and can be large. The muon survival rates in experiments with very long baselines thus depend on matter effects in both P μτ and P μe . We also indicate where these effects provide sensitivity to θ 13 and identify ranges of energies and baselines where this sensitivity is maximum. The effect of parameter degeneracies in the three probabilities at these baselines and energies is studied in detail and large parts of the parameter space are identified which are free from these degeneracies. In the second part of the paper, we focus on using the matter effects studied in the first part as a means of determining the mass hierarchy via atmospheric neutrinos. Realistic event rate calculations are performed for a charge discriminating 100 kT iron calorimeter which demonstrate the possibility of realizing this very important goal in neutrino physics. It is shown that for atmospheric neutrinos, a careful selection of energy and baseline ranges is necessary in order to obtain a statistically significant signal, and that the effects are largest in bins where matter effects in both P μe and P μτ combine constructively. Under these conditions, up to a 4σ signal for matter effects is possible (for Δ 31 >0) within a time scale appreciably shorter than the one anticipated for neutrino factories

Improving the accuracy of energy baseline models for commercial buildings with occupancy data

International Nuclear Information System (INIS)

Liang, Xin; Hong, Tianzhen; Shen, Geoffrey Qiping

2016-01-01

Highlights: • We evaluated several baseline models predicting energy use in buildings. • Including occupancy data improved accuracy of baseline model prediction. • Occupancy is highly correlated with energy use in buildings. • This simple approach can be used in decision makings of energy retrofit projects. - Abstract: More than 80% of energy is consumed during operation phase of a building’s life cycle, so energy efficiency retrofit for existing buildings is considered a promising way to reduce energy use in buildings. The investment strategies of retrofit depend on the ability to quantify energy savings by “measurement and verification” (M&V), which compares actual energy consumption to how much energy would have been used without retrofit (called the “baseline” of energy use). Although numerous models exist for predicting baseline of energy use, a critical limitation is that occupancy has not been included as a variable. However, occupancy rate is essential for energy consumption and was emphasized by previous studies. This study develops a new baseline model which is built upon the Lawrence Berkeley National Laboratory (LBNL) model but includes the use of building occupancy data. The study also proposes metrics to quantify the accuracy of prediction and the impacts of variables. However, the results show that including occupancy data does not significantly improve the accuracy of the baseline model, especially for HVAC load. The reasons are discussed further. In addition, sensitivity analysis is conducted to show the influence of parameters in baseline models. The results from this study can help us understand the influence of occupancy on energy use, improve energy baseline prediction by including the occupancy factor, reduce risks of M&V and facilitate investment strategies of energy efficiency retrofit.

Effects of baseline conditions on the simulated hydrologic response to projected climate change

Science.gov (United States)

Koczot, Kathryn M.; Markstrom, Steven L.; Hay, Lauren E.

2011-01-01

Changes in temperature and precipitation projected from five general circulation models, using one late-twentieth-century and three twenty-first-century emission scenarios, were downscaled to three different baseline conditions. Baseline conditions are periods of measured temperature and precipitation data selected to represent twentieth-century climate. The hydrologic effects of the climate projections are evaluated using the Precipitation-Runoff Modeling System (PRMS), which is a watershed hydrology simulation model. The Almanor Catchment in the North Fork of the Feather River basin, California, is used as a case study. Differences and similarities between PRMS simulations of hydrologic components (i.e., snowpack formation and melt, evapotranspiration, and streamflow) are examined, and results indicate that the selection of a specific time period used for baseline conditions has a substantial effect on some, but not all, hydrologic variables. This effect seems to be amplified in hydrologic variables, which accumulate over time, such as soil-moisture content. Results also indicate that uncertainty related to the selection of baseline conditions should be evaluated using a range of different baseline conditions. This is particularly important for studies in basins with highly variable climate, such as the Almanor Catchment.

Infrared thermometry and the crop water stress index. I. History, theory, and baselines

International Nuclear Information System (INIS)

Gardner, B.R.; Nielsen, D.C.; Shock, C.C.

1992-01-01

Development of portable infrared thermometers and the definition of the Crop Water Stress Index (CWSI) have led to widespread interest in infrared thermometry to monitor water stress and schedule irrigations. But the CWSI concept is still new and poorly understood by many. The purpose of this paper is to review the definition of CWSI, and the determination and interpretation of the non-water-stressed baselines used to compute CWSI. The non-water-stressed baseline equation normalizes the canopy minus air temperature differential for variations in vapor pressure deficit. Non-water-stressed baselines can be determined empirically from measurements of canopy and air temperatures and vapor pressure deficit, made diurnally on a single day, or at a single time of day over many days, on well-watered plants. The value of the maximum canopy minus air temperature differential under maximum water stress should also be determined empirically. Causes for CWSI values falling outside of the defined 0 to 10 unit range are reviewed. Non-water-stressed baselines may shift with plant growth stage. Effective use of CWSI is dependent on understanding the definition of CWSI, and the proper determination and use of non-water-stressed baselines. (author)

Leveraging probabilistic peak detection to estimate baseline drift in complex chromatographic samples.

Science.gov (United States)

Lopatka, Martin; Barcaru, Andrei; Sjerps, Marjan J; Vivó-Truyols, Gabriel

2016-01-29

Accurate analysis of chromatographic data often requires the removal of baseline drift. A frequently employed strategy strives to determine asymmetric weights in order to fit a baseline model by regression. Unfortunately, chromatograms characterized by a very high peak saturation pose a significant challenge to such algorithms. In addition, a low signal-to-noise ratio (i.e. s/npeak detection algorithm. A posterior probability of being affected by a peak is computed for each point in the chromatogram, leading to a set of weights that allow non-iterative calculation of a baseline estimate. For extremely saturated chromatograms, the peak weighted (PW) method demonstrates notable improvement compared to the other methods examined. However, in chromatograms characterized by low-noise and well-resolved peaks, the asymmetric least squares (ALS) and the more sophisticated Mixture Model (MM) approaches achieve superior results in significantly less time. We evaluate the performance of these three baseline correction methods over a range of chromatographic conditions to demonstrate the cases in which each method is most appropriate. Copyright © 2016 Elsevier B.V. All rights reserved.