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Sample records for residual damage gsi

  1. DNA-DSB in CHO-K1 cells induced by heavy-ions: Break rejoining and residual damage (GSI)

    NASA Technical Reports Server (NTRS)

    Taucher-Scholz, G.; Heilmann, J.; Becher, G.; Kraft, G.

    1994-01-01

    DNA double strand breaks (DSB's) are the critical lesions involved in cellular effects of ionizing radiation. Therefore, the evaluation of DSB induction in mammalian cells after heavy ion irradiation is an essential task for the assessment of high-LET radiation risk in space. Of particular interest has been the question of how the biological efficiency for the cellular inactivation endpoint relates to the initial lesions (DSBs) at varying LETs. For cell killing, an increased Relative Biological Efficiency (RBE) has been determined for highLET radiation around 100-200 keV/mu m. At higher LET, the RBE's decrease again to values below one for the very heavy particles. At GSI, DSB-induction was measured in CHO-K1 cells following irradiation with accelerated particles covering a wide LET range. The electrophoretic elution of fragmented DNA out of agarose plugs in a constant electrical field was applied for the detection of DSB's. The fraction of DNA retained was determined considering the relative intensities of ethidium bromide fluorescence in the well and in the gel lane. Dose-effect curves were established, from which the RBE for DSB induction was calculated at a fraction of 0.7 of DNA retained In summary, these rejoining studies are in line with an enhanced severity of the DNA DSB's at higher LET's, resulting in a decreased repairability of the induced lesions. However, no information concerning the fidelity of strand breaks rejoining is provided in these studies. To assess correct rejoining of DNA fragments an experimental system involving individual DNA hybridization bands has been set up. In preliminary experiments Sal I generated DNA fragments of 0.9 Mbp were irradiated with xrays and incubated for repair However, restitution of the original signals was not observed, probably due to the high radiation dose necessary for breakage of a fragment of this size. A banding pattern with NotI hybridization signals in a higher MW range (3Mbp) has been obtained by varying

  2. Residual strength of damaged marine structures

    NASA Astrophysics Data System (ADS)

    Ghose, Dhruba J.; Nappi, Natale S.; Wiernicki, Christopher J.

    1994-09-01

    Traditionally assessment of ship's longitudinal strength has been made by comparing the elastic stresses at the deck or bottom shell to fractions of the material yield strength. This results in high reserve capacity due to inherent redundancies in ship structures. Residual strength, which is defined as the strength of the structure after damage, has rarely been considered either during design or at the time of repair. In this report, key elements required to undertake an engineering analysis to evaluate the residual strength have been identified. Emphasis has been placed on assessing the residual strength of marine structures damaged due to normal operating loads. Methods available to industry for evaluation of damage such as, fracture and ultimate strength have been summarized. An example problem, illustrating the application of an integrated approach to residual strength assessment on a particular ship type, is presented.

  3. Residual Strength of Blast Damaged Reinforced Concrete Columns

    DTIC Science & Technology

    2010-07-01

    both reinforced concrete columns and shear walls during seismic investigations [14]. 4.2.3. Effect of longitudinal reinforcement ratio As the...Residual strength of blast damaged reinforced concrete columns Xiaoli Bao, Bing Li* School of Civil and Environmental Engineering, Nanyang...DATES COVERED - 4. TITLE AND SUBTITLE Residual strength of blast damaged reinforced concrete columns 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  4. Mechanical relaxation of localized residual stresses associatedwith foreign object damage

    SciTech Connect

    Boyce, B.L.; Chen, X.; Peters, J.O.; Hutchinson, J.H.; Ritchie,R.O.

    2002-05-01

    Foreign-object damage associated with the ingestion ofdebris into aircraft turbine engines can lead to a marked degradation inthe high-cycle fatigue life of turbine components. This degradation isgenerally considered to be associated with the premature initiation offatigue cracks at or near the damage sites; this is suspected to be dueto, at least in part, the impact-induced residual stress state, which canbe strongly tensile in these locations.

  5. FAIR project at GSI

    NASA Astrophysics Data System (ADS)

    Kester, Oliver; Spiller, Peter; Stoecker, Horst

    FAIR -- the Facility for Antiproton and Ion Research in Europe -- constructed at GSI Helmholtzzentrum für Schwerionenforschung GmbH in Darmstadt comprises an international centre of heavy ion accelerators that will drive heavy ion and antimatter research (FBTR, 2006). FAIR will provide worldwide unique accelerator and experimental facilities allowing a large variety of fore-front research in physics and applied science. FAIR will deliver antiproton and ion beams of unprecedented intensities and qualities. The main part of the FAIR facility is a sophisticated and cost efficient accelerator system, which delivers parallel beams to different experiments of the FAIR experimental collaborations -- APPA, NuSTAR, CBM and PANDA. The accelerated primary beams will then be employed to create new, often highly exotic particles in a series of parallel experimental programs. Experiments with exotic particles will explore fundamental processes which are expected to have taken place in the early phases and still happen in the on-going evolution of the Universe. These processes produced the basic constituents of matter and overall structure we observe today...

  6. Residual Strength Prediction of Fuselage Structures with Multiple Site Damage

    NASA Technical Reports Server (NTRS)

    Chen, Chuin-Shan; Wawrzynek, Paul A.; Ingraffea, Anthony R.

    1999-01-01

    This paper summarizes recent results on simulating full-scale pressure tests of wide body, lap-jointed fuselage panels with multiple site damage (MSD). The crack tip opening angle (CTOA) fracture criterion and the FRANC3D/STAGS software program were used to analyze stable crack growth under conditions of general yielding. The link-up of multiple cracks and residual strength of damaged structures were predicted. Elastic-plastic finite element analysis based on the von Mises yield criterion and incremental flow theory with small strain assumption was used. A global-local modeling procedure was employed in the numerical analyses. Stress distributions from the numerical simulations are compared with strain gage measurements. Analysis results show that accurate representation of the load transfer through the rivets is crucial for the model to predict the stress distribution accurately. Predicted crack growth and residual strength are compared with test data. Observed and predicted results both indicate that the occurrence of small MSD cracks substantially reduces the residual strength. Modeling fatigue closure is essential to capture the fracture behavior during the early stable crack growth. Breakage of a tear strap can have a major influence on residual strength prediction.

  7. Statistical moments of autoregressive model residuals for damage localisation

    NASA Astrophysics Data System (ADS)

    Mattson, Steven G.; Pandit, Sudhakar M.

    2006-04-01

    Monitoring structural health is a problem with significant importance in the world today. Aging civil infrastructure and aircraft fleets have made non-destructive evaluation an important research topic. Non-destructive techniques based on dynamic signatures have struggled to gain widespread acceptance due to the perceived difficulty in applying these methods, as well as the mixed results they can produce. A simple and reliable method that is useful without in-depth knowledge of the structure is necessary to transition dynamic response-based health monitoring into the industrial mainstream. Modal parameters, including shifting frequencies, damping ratios, and mode shapes have received considerable attention as damage indicators. The results have been mixed and require an expert to carry out the testing and interpretation. Detailed knowledge of the structure before it becomes damaged is required, either in the form of experimental data or an analytical model. A method based on vector autoregressive (ARV) models is proposed. These models accurately capture the predictable dynamics present in the response. They leave the unpredictable portion, including the component resulting from unmeasured input shocks, in the residual. An estimate of the autoregressive model residual series standard deviation provides an accurate diagnosis of damage conditions. Additionally, a repeatable threshold level that separates damaged from undamaged is identified, indicating the possibility of damage identification and localisation without explicit knowledge of the undamaged structure. Similar statistical analysis applied to the raw data necessitates the use of higher-order moments that are more sensitive to disguised outliers, but are also prone to false indications resulting from overemphasising rarely occurring extreme values. Results are included from data collected using an eight-degree of freedom damage simulation test-bed, built and tested at Los Alamos National Laboratory (LANL

  8. A methodology to predict damage initiation, damage growth and residual strength in titanium matrix composites

    NASA Technical Reports Server (NTRS)

    Bakuckas, J. G., Jr.; Johnson, W. S.

    1994-01-01

    In this research, a methodology to predict damage initiation, damage growth, fatigue life, and residual strength in titanium matrix composites (TMC) is outlined. Emphasis was placed on micromechanics-based engineering approaches. Damage initiation was predicted using a local effective strain approach. A finite element analysis verified the prevailing assumptions made in the formulation of this model. Damage growth, namely, fiber-bridged matrix crack growth, was evaluated using a fiber bridging (FB) model which accounts for thermal residual stresses. This model combines continuum fracture mechanics and micromechanics analyses yielding stress-intensity factor solutions for fiber-bridged matrix cracks. It is assumed in the FB model that fibers in the wake of the matrix crack are idealized as a closure pressure, and an unknown constant frictional shear stress is assumed to act along the debond length of the bridging fibers. This frictional shear stress was used as a curve fitting parameter to the available experimental data. Fatigue life and post-fatigue residual strength were predicted based on the axial stress in the first intact 0 degree fiber calculated using the FB model and a three-dimensional finite element analysis.

  9. Residual force enhancement following eccentric induced muscle damage.

    PubMed

    Power, Geoffrey A; Rice, Charles L; Vandervoort, Anthony A

    2012-06-26

    During lengthening of an activated skeletal muscle, the force maintained following the stretch is greater than the isometric force at the same muscle length. This is termed residual force enhancement (RFE), but it is unknown how muscle damage following repeated eccentric contractions affects RFE. Using the dorsiflexors, we hypothesised muscle damage will impair the force generating sarcomeric structures leading to a reduction in RFE. Following reference maximal voluntary isometric contractions (MVC) in 8 young men (26.5±2.8y) a stretch was performed at 30°/s over a 30° ankle excursion ending at the same muscle length as the reference MVCs (30° plantar flexion). Surface electromyography (EMG) of the tibialis anterior and soleus muscles was recorded during all tasks. The damage protocol involved 4 sets of 25 isokinetic (30°/s) lengthening contractions. The same measures were collected at baseline and immediately post lengthening contractions, and for up to 10min recovery. Following the lengthening contraction task, there was a 30.3±6.4% decrease in eccentric torque (P<0.05) and 36.2±9.7% decrease in MVC (P<0.05) compared to baseline. Voluntary activation using twitch interpolation and RMS EMG amplitude of the tibialis anterior remained near maximal without increased coactivation for MVC. Contrary to our hypothesis, RFE increased (∼100-250%) following muscle damage (P<0.05). It appears stretch provided a mechanical strategy for enhanced muscle function compared to isometric actions succeeding damage. Thus, active force of cross-bridges is decreased because of impaired excitation-contraction coupling but force generated during stretch remains intact because force contribution from stretched sarcomeric structures is less impaired.

  10. Extra lethal damage due to residual incompletely repaired sublethal damage in hyperfractionated and continuous radiation treatment

    SciTech Connect

    Chen, J.; van de Geijn, J.; Goffman, T. )

    1991-05-01

    In the conventional linear--quadratic model of single-dose response, the {alpha} and {beta} terms reflect lethal damage created {ital during} the delivery of a dose, from two different presumed molecular processes, one linear with dose, the other quadratic. With the conventional one-fraction-per-day (or less) regimens, the sublethal damage (SLD), presumably repairing exponentially over time, is essentially completely fixed by the time of the next dose of radiation. If this assumption is true, the effects of subsequent fractions of radiation should be independent, that is, there should be little, if any, reversible damage left from previous fractions, at the time of the next dose. For multiple daily fractions, or for the limiting case, continuous radiation, this simplification may overlook damaged cells that have had insufficient time for repair. A generalized method is presented for accounting for extra lethal damage (ELD) arising from such residual SLD for hyperfractionation and continuous irradiation schemes. It may help to predict differences in toxicity and tumor control, if any, obtained with unconventional'' treatment regimens. A key element in the present model is the finite size and the dynamic character of the pool of sublethal damage. Besides creating the usual linear and quadratic components of lethal damage, each new fraction converts a certain fraction of the existing SLD into ELD, and creates some new SLD.

  11. Introducing Object-Oriented Concepts into GSI

    NASA Technical Reports Server (NTRS)

    Guo, Jing; Todling, Ricardo

    2017-01-01

    Enhancements are now being made to the Gridpoint Statistical Interpolation (GSI) data assimilation system to expand its capabilities. This effort opens the way for broadening the scope of GSI's applications by using some standard object-oriented features in Fortran, and represents a starting point for the so-called GSI refactoring, as a part of the Joint Effort for Data-assimilationI ntegration (JEDI) project of JCSDA.

  12. Damage localization and quantification of composite stratified beam Structures using residual force method

    NASA Astrophysics Data System (ADS)

    Behtani, A.; Bouazzouni, A.; Khatir, S.; Tiachacht, S.; Zhou, Y.-L.; Abdel Wahab, M.

    2017-05-01

    In this paper, the problem of using measured modal parameters to detect and locate damage in beam composite stratified structures with four layers of graphite/epoxy [0°/902°/0°] is investigated. A technique based on the residual force method is applied to composite stratified structure with different boundary conditions, the results of damage detection for several damage cases demonstrate that using residual force method as damage index, the damage location can be identified correctly and the damage extents can be estimated as well.

  13. Future Facility: FAIR at GSI

    NASA Astrophysics Data System (ADS)

    Rosner, Guenther

    2007-05-01

    The Facility for Antiproton and Ion Research, FAIR, is a new particle accelerator facility to be built at the GSI site in Germany. The research at FAIR will cover a wide range of topics in nuclear and hadron physics, high density plasma and atomic physics, and applications in condensed matter physics and biology. A 1.1 km circumference double ring of rapidly cycling 100 and 300 Tm synchrotrons, will be FAIR's central accelerator system. It will be used to produce, inter alia, high intensity secondary beams of antiprotons and short-lived radioactive nuclei. A subsequent suite of cooler and storage rings will deliver heavy ion and antiproton beams of unprecedented quality. Large experiments are presently being designed by the NUSTAR, PANDA, PAX, CBM, SPARC, FLAIR, HEDgeHOB and BIOMAT collaborations.

  14. The new data acquisition system at GSI

    SciTech Connect

    Essel, H.G.; Hoffmann, J.; Kurz, N.; Mayer, R.S.; Ott, W.; Schall, D.

    1996-02-01

    The new general purpose data acquisition system developed at GSI is currently installed at about 30 experiments at GSI and other sites. It is based on the LynxOS operating system. Several CPUs, i.e. GSI developed CAMAC computer boards, VME processor boards, and Aleph Event Builders, are connected by a memory mapped bus, i.e. a VSB or VME bus. It can be configured easily for various hardware setups and is highly optimized for fast trigger rates and data throughput. The first and successful experiment taking data with the system was the SHIP production run for elements 110 and 111.

  15. The FIRST experiment at GSI

    NASA Astrophysics Data System (ADS)

    Pleskac, R.; Abou-Haidar, Z.; Agodi, C.; Alvarez, M. A. G.; Aumann, T.; Battistoni, G.; Bocci, A.; Böhlen, T. T.; Boudard, A.; Brunetti, A.; Carpinelli, M.; Cirrone, G. A. P.; Cortes-Giraldo, M. A.; Cuttone, G.; De Napoli, M.; Durante, M.; Fernández-García, J. P.; Finck, C.; Golosio, B.; Gallardo, M. I.; Iarocci, E.; Iazzi, F.; Ickert, G.; Introzzi, R.; Juliani, D.; Krimmer, J.; Kurz, N.; Labalme, M.; Leifels, Y.; Le Fevre, A.; Leray, S.; Marchetto, F.; Monaco, V.; Morone, M. C.; Oliva, P.; Paoloni, A.; Piersanti, L.; Quesada, J. M.; Raciti, G.; Randazzo, N.; Romano, F.; Rossi, D.; Rousseau, M.; Sacchi, R.; Sala, P.; Sarti, A.; Scheidenberger, C.; Schuy, C.; Sciubba, A.; Sfienti, C.; Simon, H.; Sipala, V.; Spiriti, E.; Stuttge, L.; Tropea, S.; Younis, H.; Patera, V.

    2012-06-01

    The FIRST (Fragmentation of Ions Relevant for Space and Therapy) experiment at the SIS accelerator of GSI laboratory in Darmstadt has been designed for the measurement of ion fragmentation cross-sections at different angles and energies between 100 and 1000 MeV/nucleon. Nuclear fragmentation processes are relevant in several fields of basic research and applied physics and are of particular interest for tumor therapy and for space radiation protection applications. The start of the scientific program of the FIRST experiment was on summer 2011 and was focused on the measurement of 400 MeV/nucleon 12C beam fragmentation on thin (8 mm) graphite target. The detector is partly based on an already existing setup made of a dipole magnet (ALADiN), a time projection chamber (TP-MUSIC IV), a neutron detector (LAND) and a time of flight scintillator system (TOFWALL). This pre-existing setup has been integrated with newly designed detectors in the Interaction Region, around the carbon target placed in a sample changer. The new detectors are a scintillator Start Counter, a Beam Monitor drift chamber, a silicon Vertex Detector and a Proton Tagger scintillator system optimized for the detection of light fragments emitted at large angles. In this paper we review the experimental setup, then we present the simulation software, the data acquisition system and finally the trigger strategy of the experiment.

  16. Evaluation of residual strength of composite laminates damaged by low velocity impacts

    NASA Technical Reports Server (NTRS)

    Lal, K. M.

    1986-01-01

    This work presents the study of Low Velocity Transverse Impact damage of graphite-epoxy T300/5208 composite material. An energy dissipation model was developed to predict the residual strength from fracture mechanics concepts. The specimens, 100 mm diameter clamped plates, were impact damaged by a cantilever-type instrumented 1-inch diameter steel ball. This study was limited to impact velocity 6 m/sec. Rectangular strips, 50 mm x 125 mm, were cut from the impact-damaged specimens so that the impact damage zone was in the center of the strips. These strips were tested to obtain their residual strength. Predictions were compared with the test results.

  17. An examination of the ARX as a residual generator for damage detection

    NASA Astrophysics Data System (ADS)

    Bernal, Dionisio; Zonta, Daniele; Pozzi, Matteo

    2009-03-01

    Residuals that capture the difference between anticipated behavior and actual observations are often used to identify damage. Wanting to control the influence of unmeasured disturbances and noise in residuals, it is common to generate reference signals using feedback from measured outputs. Since there is much flexibility in the gains a wide range of models that react differently to changes are possible. This paper examines two questions: 1) how damage residuals generated by different closed loop models relate to each other and 2) how to rank the expected efficiency of alternative models. On the first question examination shows that the residuals from any model can be viewed as sums of filtered open loop residuals where the filter coefficients depend on the model structure but not on the damage. On the second item a general procedure based on Bayesian decision-making is proposed to quantify the economical benefit in adopting a specific autoregressive model.

  18. Mouse bone marrow cytogenetic damage produced by residues of tequila.

    PubMed

    Madrigal-Bujaidar, E; Rojas, A; Ramos, A; Rosas, E; Díaz Barriga-Arceo, S

    1990-06-01

    Five concentrations (50-860 mg/kg) of residues obtained after distillation and lyophilization of commercial tequila were injected into mice for evaluation of chromosome aberrations, sister-chromatid exchanges, and proliferation kinetics in mouse bone marrow cells. Appropriate positive and negative controls were included. Our results showed significant dose-related increases of chromosomal aberrations starting at 50 mg/kg and for sister-chromatid exchanges at 430 mg/kg. Cellular proliferation kinetics showed no alterations. With these data we demonstrated that the residues of tequila are genotoxic in vivo.

  19. Interpretation of body residues for natural resources damage assessment

    SciTech Connect

    Kubitz, J.A.; Markarian, R.K.; Lauren, D.J.; Dimitry, J.A. |

    1995-12-31

    A 28-day caged mussel study using Corbicula sp. was conducted on Sugarland Run and the Potomac River following a spill of No. 2 fuel oil. In addition, resident Corbicula sp. from the Potomac River were sampled at the beginning and end of the study. The summed body residues of 39 polycyclic aromatic hydrocarbons (PAHs) ranged from 0.56 to 41 mg/kg dry weight within the study area. The summed body residues of the 18 PAHs that are routinely measured in the national oceanic and Atmospheric Administration Status and Trends Program (NST) ranged from 0.5 to 20 mg/kg dry weight for mussels in this study. These data were similar to summed PAH concentrations reported in the NST for mussels from a variety of US coastal waters, which ranged from 0.4 to 24.5 mg/kg dry weight. This paper will discuss interpretation of PAH residues in Corbicula sp. to determine the spatial extent of the area affected by the oil spill. The toxicological significance of the PAH residues in both resident and caged mussels will also be presented.

  20. Residual tree damage during selection cuts using two skidding systems in the Missouri Ozarks

    Treesearch

    Robert L. Ficklin; John P. Dwyer; Bruce E. Cutter; Tom Draper

    1997-01-01

    Today, there is an interest in using alternative silvicultural systems like selection and two-aged management, because the public finds these systems more acceptable than clearcutting. However, repeated entries into forest stands to remove timber increase the risk of residual stand damage. Harvest techniques are desirable that (1) reduce the risk of stand damage and (2...

  1. Residual Strength of Composites with Multiple Impact Damage

    DTIC Science & Technology

    1994-03-01

    Follow On Structural Fatigue Test Program ( IFOSTP ). -5- 32 The CREDP Stabilator Repair As part of the CREDP program , the Aeronautical Research Laboratory...previously developed for single impact damaged structures , was applied. This methodology was verified via a coupon test program and an experimental... test rig for a dynamic test on the IFOSTP horizontal stabilator. The stabilator was mounted in the rig by means of the

  2. Effect of Curvature on the Impact Damage Characteristics and Residual Strength of Composite Plates

    NASA Technical Reports Server (NTRS)

    Ambur, Damodar R.; Starnes, James H., Jr.

    1998-01-01

    The results of a study of the response and failure characteristics of thin, cylindrically curved, composite plates subjected to low-speed impact damage are presented. The results indicate that the plate radius and the plate thickness are important structural parameters that influence the nonlinear response of a plate for a given amount of impact energy. Analytical and experimental contact-force results are compared for several plates and the results correlate well. The impact-energy levels required to cause damage initiation and barely visible impact damage are a function of the plate radius for a given plate thickness. The impact-energy levels required to initiate impact damage for plates with a certain range of radii are greater than plates with other radii. The contact-force results corresponding to these impact-energy levels follow a similar trend. Residual strength results for plates with barely visible impact damage suggest that the compression-after-impact residual strength is also a function of plate radius. The residual strength of impact-damaged flat plates appears to be lower than the residual strength of the corresponding cylindrically curved plates.

  3. Damage detection using modal frequency curve and squared residual wavelet coefficients-based damage indicator

    NASA Astrophysics Data System (ADS)

    Yang, Chen; Oyadiji, S. Olutunde

    2017-01-01

    A theoretical and experimental study of the frequency-based damage detection method has been presented in this paper. Based on the eigenvalue problem and perturbation assumption of defect in modal response, the theoretical basis of the modal frequency curve method is established. The extraction of defect characteristics from the modal frequency curve via discrete wavelet transform is illustrated. The above background leads to the development of a new multiple-mode damage indicator for damage localisation and a damage estimator for size prediction. Then, the proposed method has been applied to aluminium samples with pre-defined damage sections. Finite element modelling and experimental testing results are presented to demonstrate the performance of the method. Additionally, detectability with respect to the various mass ratios is investigated to support the ability of the method in real applications. The numerical and experimental results suggest that the use of the damage indicator provides a more robust and unambiguous damage identification than the sole use of the wavelet coefficients of the modes investigated. In addition, the damage estimator predicts the defect size to a satisfactory level.

  4. A Progressive Damage Methodology for Residual Strength Predictions of Notched Composite Panels

    NASA Technical Reports Server (NTRS)

    Coats, Timothy W.; Harris, Charles E.

    1998-01-01

    The translaminate fracture behavior of carbon/epoxy structural laminates with through-penetration notches was investigated to develop a residual strength prediction methodology for composite structures. An experimental characterization of several composite materials systems revealed a fracture resistance behavior that was very similar to the R-curve behavior exhibited by ductile metals. Fractographic examinations led to the postulate that the damage growth resistance was primarily due to fractured fibers in the principal load-carrying plies being bridged by intact fibers of the adjacent plies. The load transfer associated with this bridging mechanism suggests that a progressive damage analysis methodology will be appropriate for predicting the residual strength of laminates with through-penetration notches. A progressive damage methodology developed by the authors was used to predict the initiation and growth of matrix cracks and fiber fracture. Most of the residual strength predictions for different panel widths, notch lengths, and material systems were within about 10% of the experimental failure loads.

  5. Damage Characteristics and Residual Strength of Composite Sandwich Panels Impacted with and Without Compression Loading

    NASA Technical Reports Server (NTRS)

    McGowan, David M.; Ambur, Damodar R.

    1998-01-01

    The results of an experimental study of the impact damage characteristics and residual strength of composite sandwich panels impacted with and without a compression loading are presented. Results of impact damage screening tests conducted to identify the impact-energy levels at which damage initiates and at which barely visible impact damage occurs in the impacted facesheet are discussed. Parametric effects studied in these tests include the impactor diameter, dropped-weight versus airgun-launched impactors, and the effect of the location of the impact site with respect to the panel boundaries. Residual strength results of panels tested in compression after impact are presented and compared with results of panels that are subjected to a compressive preload prior to being impacted.

  6. Rock Mass Characterization by High-Resolution Sonic and GSI Borehole Logging

    NASA Astrophysics Data System (ADS)

    Agliardi, F.; Sapigni, M.; Crosta, G. B.

    2016-11-01

    We investigate the relationships between the in situ P-wave velocity (Vp) of rock masses, measured by borehole acoustic logging, and their Geological Strength Index (GSI), to support a reliable assessment of equivalent continuum rock mass properties at depth. We quantified both Vp and GSI in three deep boreholes drilled in a crystalline core complex of the central Italian Alps. The boreholes were driven up to 400 m in depth and provided high-quality drill cores in gneiss, schist and metasedimentary rocks with variable lithology. Geological and geomechanical logging was carried out for over 800 m of cores, and acoustic logging was performed for more than 600 m of borehole length. High-resolution core logging in terms of GSI was obtained using an original quantitative approach. Candidate empirical correlation functions linking Vp and GSI were tested by a two-step statistical analysis of the experimental dataset, including outlier removal and nonlinear regression analysis. We propose a sigmoid Vp-GSI equation valid over a depth range between 100 and 400 m. This accounts for extremely variable lithological, weathering and rock mass damage conditions, complementing existing shallow-depth approaches and showing potential for practical applications in different engineering settings.

  7. Coal tar residues produce both DNA adducts and oxidative DNA damage in human mammary epithelial cells.

    PubMed

    Leadon, S A; Sumerel, J; Minton, T A; Tischler, A

    1995-12-01

    In the present study we compare the metabolic activation of coal tar, as measured by the production of both DNA adducts and oxidative DNA damage, with that of a single carcinogen that is a constituent of this complex mixture in human mammary epithelial cells (HMEC). We find that a significant level of DNA adducts, detected by 32P-postlabeling, are formed in HMEC following exposure to coal tar residues. This treatment also results in the generation of high levels of oxidative DNA damage, as measured by the production of one type of oxidative base modification, thymine glycols. The amounts of both DNA adducts and thymine varied considerably between the various coal tar residues and did not correlate with either the total amount of polycyclic aromatic hydrocarbons (PAH) or the amount of benzo[a]pyrene (B[a]P) present in the residue. Fractionating the residue from one of the sites by sequential extraction with organic solvents indicated that while the ability to produce both types of DNA damage was contained mostly in a hexane-soluble fraction, a benzene-soluble fraction produced high levels of reactive oxygens relative to the number of total DNA adducts. We find that the total amount of PAH or B[a]P present in the coal tars from the various sites was not a predictor of the level of total DNA damage formed.

  8. Glucose autoxidation induces functional damage to proteins via modification of critical arginine residues.

    PubMed

    Chetyrkin, Sergei; Mathis, Missy; Pedchenko, Vadim; Sanchez, Otto A; McDonald, W Hayes; Hachey, David L; Madu, Hartman; Stec, Donald; Hudson, Billy; Voziyan, Paul

    2011-07-12

    Nonenzymatic modification of proteins in hyperglycemia is a major mechanism causing diabetic complications. These modifications can have pathogenic consequences when they target active site residues, thus affecting protein function. In the present study, we examined the role of glucose autoxidation in functional protein damage using lysozyme and RGD-α3NC1 domain of collagen IV as model proteins in vitro. We demonstrated that glucose autoxidation induced inhibition of lysozyme activity as well as NC1 domain binding to α(V)β(3) integrin receptor via modification of critical arginine residues by reactive carbonyl species (RCS) glyoxal (GO) and methylglyoxal while nonoxidative glucose adduction to the protein did not affect protein function. The role of RCS in protein damage was confirmed using pyridoxamine which blocked glucose autoxidation and RCS production, thus protecting protein function, even in the presence of high concentrations of glucose. Glucose autoxidation may cause protein damage in vivo since increased levels of GO-derived modifications of arginine residues were detected within the assembly interface of collagen IV NC1 domains isolated from renal ECM of diabetic rats. Since arginine residues are frequently present within protein active sites, glucose autoxidation may be a common mechanism contributing to ECM protein functional damage in hyperglycemia and oxidative environment. Our data also point out the pitfalls in functional studies, particularly in cell culture experiments, that involve glucose treatment but do not take into account toxic effects of RCS derived from glucose autoxidation.

  9. Birefringence and residual stress induced by CO2 laser mitigation of damage growth in fused silica

    NASA Astrophysics Data System (ADS)

    Gallais, L.; Cormont, P.; Rullier, J. L.

    2009-10-01

    We investigate the residual stress field created near mitigated sites and its influence on the efficiency on the CO2 laser mitigation of damage growth process. A numerical model of CO2 laser interaction with fused silica is developed that take into account laser energy absorption, heat transfer, thermally-induced stress and birefringence. Specific photoelastic methods are developed to characterize the residual stress near mitigated sites in fused silica samples. The stress distribution and quantitative values of stress levels are obtained for sites treated with the CO2 laser in various conditions of energy deposition (beam size, pulse duration, incident power). The results obtained also show that the presence of birefringence/residual stress around the mitigated sites has a critical effect on their laser damage resistance.

  10. Superheavy Element Research at Tasca at GSI

    NASA Astrophysics Data System (ADS)

    Düllmann, Christoph E.

    2014-09-01

    Experiments on the synthesis of the heaviest elements are in the center of the current research program on superheavy elements at GSI Darmstadt. At the gas-filled recoil separator TASCA, search experiments for the new elements 119 and 120 have been performed in the reactions 50Ti + 249Bk and 50Ti + 249Cf, respectively, and the production of element 117 in the reaction 48Ca + 249Bk was studied. The experiments were performed successfully and the data are currently under analysis.

  11. Logging damage to residual trees following commercial harvesting to different overstory retention levels in a mature hardwood stand in Tennessee

    Treesearch

    Wayne K. Clatterbuck

    2006-01-01

    Partial cutting in mature hardwood stands often causes physical damage to residual stems through felling and skidding resulting in a decline in bole quality and subsequent loss of tree value. This study assessed the logging damage to residual trees following commercial harvesting in a fully stocked, mature oak-hickory stand cut to three overstory basal area retention...

  12. Residual strength assessment of low velocity impact damage of graphite-epoxy laminates

    NASA Technical Reports Server (NTRS)

    Lal, K. M.

    1983-01-01

    This report contains the study of Low Velocity Transverse Impact Damage of graphite-epoxy T300/5208 composite laminates. The specimen, 100 mm diameter clamped plates, were impact damaged by a cantilever-type instrumented 1-inch diameter steel ball. Study was limited to impact velocity 6 m/sec. Rectangular strips, 50 mm x 125 mm, were cut from the impact-damage specimens so that the impact damage zone was in the center of the strips. These strips were tested in tension to obtain their residual strength. An energy dissipation model was developed to predict the residual strength from fracture mechanics concepts. Net energy absorbed I(a) was evaluated from coefficient of restitution concepts based on shear dominated theory of fiber-reinforced materials, with the modification that during loading and unloading the shear deformation are respectively elastic-plastic and elastic. Delamination energy I(d) was predicted by assuming that the stiffness of the laminate dropped due to debonding. Fiber-breakage energy, assumed to be equal to the difference of I(a) and I(d), was used to determine the residual strength. Predictions were compared with test results.

  13. Fatigue is more damaging than creep in ligament revealed by modulus reduction and residual strength.

    PubMed

    Thornton, Gail M; Schwab, Timothy D; Oxland, Thomas R

    2007-10-01

    Following injury of a complementary joint restraint, ligaments can be subjected to higher than normal stresses. Normal ligaments are exposed to static (creep) and cyclic (fatigue) loading from which damage can accumulate at these higher than normal stresses. This study tracked damage accumulation during creep and fatigue loading of normal rabbit medial collateral ligaments (MCLs) over a range of stresses, using modulus reduction as a marker of damage. Creep tests were interrupted occasionally with unloading/reloading cycles to measure modulus. Test stresses were normalized to ultimate tensile strength (UTS): 60%, 30%, and 15% UTS. Not all creep and fatigues tests progressed until rupture but were stopped and followed by an assessment of the residual strength of that partially damaged ligament using a monotonic failure test. Fatigue loading caused earlier modulus reduction than creep. Modulus reduction occurred at lower increases in strain (strain relative to initial strain) for fatigue than creep. In other words, at the same time or increase in strain, fatigue is more damaging than creep because the modulus ratio reduction is greater. These findings suggest that creep and fatigue have different strain and damage mechanisms. Ligaments exposed to creep or fatigue loading which produced a modulus reduction had decreased residual strength and increased toe-region strain in a subsequent monotonic failure test. This finding confirmed that modulus reduction during creep and fatigue is a suitable marker of partial damage in ligament. Cyclic loading caused damage earlier than static loading, likely an important consideration when ligaments are loaded to higher than normal magnitudes following injury of a complementary joint restraint.

  14. On Using Residual Voltage to Estimate Electrode Model Parameters for Damage Detection

    PubMed Central

    Krishnan, Ashwati; Kelly, Shawn K.

    2016-01-01

    Current technology has enabled a significant increase in the number of electrodes for electrical stimulation. For large arrays of electrodes, it becomes increasingly difficult to monitor and detect failures at the stimulation site. In this paper, we propose the idea that the residual voltage from a biphasic electrical stimulation pulse can serve to recognize damage at the electrode-tissue interface. We use a simple switch circuit approach to estimate the relaxation time constant of the electrode model, which essentially models the residual voltage in biphasic electrical stimulation, and compare it with standard electrode characterization techniques. Out of 15 electrodes in a polyimide-based SIROF array, our approach highlights 3 damaged electrodes, consistent with measurements made using cyclic voltammetry and electrode impedance spectroscopy. PMID:27231725

  15. Vision restoration after brain and retina damage: the "residual vision activation theory".

    PubMed

    Sabel, Bernhard A; Henrich-Noack, Petra; Fedorov, Anton; Gall, Carolin

    2011-01-01

    Vision loss after retinal or cerebral visual injury (CVI) was long considered to be irreversible. However, there is considerable potential for vision restoration and recovery even in adulthood. Here, we propose the "residual vision activation theory" of how visual functions can be reactivated and restored. CVI is usually not complete, but some structures are typically spared by the damage. They include (i) areas of partial damage at the visual field border, (ii) "islands" of surviving tissue inside the blind field, (iii) extrastriate pathways unaffected by the damage, and (iv) downstream, higher-level neuronal networks. However, residual structures have a triple handicap to be fully functional: (i) fewer neurons, (ii) lack of sufficient attentional resources because of the dominant intact hemisphere caused by excitation/inhibition dysbalance, and (iii) disturbance in their temporal processing. Because of this resulting activation loss, residual structures are unable to contribute much to everyday vision, and their "non-use" further impairs synaptic strength. However, residual structures can be reactivated by engaging them in repetitive stimulation by different means: (i) visual experience, (ii) visual training, or (iii) noninvasive electrical brain current stimulation. These methods lead to strengthening of synaptic transmission and synchronization of partially damaged structures (within-systems plasticity) and downstream neuronal networks (network plasticity). Just as in normal perceptual learning, synaptic plasticity can improve vision and lead to vision restoration. This can be induced at any time after the lesion, at all ages and in all types of visual field impairments after retinal or brain damage (stroke, neurotrauma, glaucoma, amblyopia, age-related macular degeneration). If and to what extent vision restoration can be achieved is a function of the amount of residual tissue and its activation state. However, sustained improvements require repetitive

  16. A Progressive Damage Methodology for Residual Strength Predictions of Center-Crack Tension Composite Panels

    NASA Technical Reports Server (NTRS)

    Coats, Timothy William

    1996-01-01

    An investigation of translaminate fracture and a progressive damage methodology was conducted to evaluate and develop a residual strength prediction capability for laminated composites with through penetration notches. This is relevant to the damage tolerance of an aircraft fuselage that might suffer an in-flight accident such as an uncontained engine failure. An experimental characterization of several composite materials systems revealed an R-curve type of behavior. Fractographic examinations led to the postulate that this crack growth resistance could be due to fiber bridging, defined here as fractured fibers of one ply bridged by intact fibers of an adjacent ply. The progressive damage methodology is currently capable of predicting the initiation and growth of matrix cracks and fiber fracture. Using two difference fiber failure criteria, residual strength was predicted for different size panel widths and notch lengths. A ply discount fiber failure criterion yielded extremely conservative results while an elastic-perfectly plastic fiber failure criterion showed that the fiber bridging concept is valid for predicting residual strength for tensile dominated failure loads. Furthermore, the R-curves predicted by the model using the elastic-perfectly plastic fiber criterion compared very well with the experimental R-curves.

  17. Residual stress and damage-induced critical fracture on CO2 laser treated fused silica

    SciTech Connect

    Matthews, M; Stolken, J; Vignes, R; Norton, M

    2009-11-02

    Localized damage repair and polishing of silica-based optics using mid- and far-IR CO{sub 2} lasers has been shown to be an effective method for increasing optical damage threshold in the UV. However, it is known that CO{sub 2} laser heating of silicate surfaces can lead to a level of residual stress capable of causing critical fracture either during or after laser treatment. Sufficient control of the surface temperature as a function of time and position is therefore required to limit this residual stress to an acceptable level to avoid critical fracture. In this work they present the results of 351 nm, 3 ns Gaussian damage growth experiments within regions of varying residual stress caused by prior CO{sub 2} laser exposures. Thermally stressed regions were non-destructively characterized using polarimetry and confocal Raman microscopy to measure the stress induced birefringence and fictive temperature respectively. For 1 {approx} 40s square pulse CO{sub 2} laser exposures created over 0.5-1.25 kW/cm{sup 2} with a 1-3 mm 1/e{sup 2} diameter beam (T{sub max} {approx} 1500-3000 K), the critical damage site size leading to fracture increases weakly with peak temperature, but shows a stronger dependence on cooling rate, as predicted by finite element hydrodynamics simulations. Confocal micro-Raman was used to probe structural changes to the glass over different thermal histories and indicated a maximum fictive temperature of 1900K for T{sub max} {ge} 2000 K. The effect of cooling rate on fictive temperature caused by CO{sub 2} laser heating are consistent with finite element calculations based on a Tool-Narayanaswamy relaxation model.

  18. Experimental measurements of surface damage and residual stresses in micro-engineered plasma facing materials

    NASA Astrophysics Data System (ADS)

    Rivera, David; Wirz, Richard E.; Ghoniem, Nasr M.

    2017-04-01

    The thermomechanical damage and residual stresses in plasma-facing materials operating at high heat flux are experimentally investigated. Materials with micro-surfaces are found to be more resilient, when exposed to cyclic high heat flux generated by an arc-jet plasma. An experimental facility, dedicated to High Energy Flux Testing (HEFTY), is developed for testing cyclic heat flux in excess of 10 MW/m2. We show that plastic deformation and subsequent fracture of the surface can be controlled by sample cooling. We demonstrate that W surfaces with micro-pillar type surface architecture have significantly reduced residual thermal stresses after plasma exposure, as compared to those with flat surfaces. X-ray diffraction (XRD) spectra of the W-(110) peak reveal that broadening of the Full Width at Half Maximum (FWHM) for micro-engineered samples is substantially smaller than corresponding flat surfaces. Spectral shifts of XRD signals indicate that residual stresses due to plasma exposure of micro-engineered surfaces build up in the first few cycles of exposure. Subsequent cyclic plasma heat loading is shown to anneal out most of the built-up residual stresses in micro-engineered surfaces. These findings are consistent with relaxation of residual thermal stresses in surfaces with micro-engineered features. The initial residual stress state of highly polished flat W samples is compressive (≈ -1.3 GPa). After exposure to 50 plasma cycles, the surface stress relaxes to -1.0 GPa. Micro-engineered samples exposed to the same thermal cycling show that the initial residual stress state is compressive at (- 250 MPa), and remains largely unchanged after plasma exposure.

  19. Vacuum arc ion source development at GSI

    SciTech Connect

    Spaedtke, P.; Emig, H.; Wolf, B.H.

    1996-08-01

    Ion beams produced by the Mevva ion source are well suited for the injection into a synchrotron accelerator due to the low repetition rate (0.2 ... 5 Hz, the higher repetition rate is for the optimization of the linear accelerator only) and the short pulse length (up to 0.5ms). From the beginning of the authors experience with the Mevva ion source at GSI they tried to improve the reliability of pulse-to-pulse reproducibility and to minimize the noise on the extracted ion beam. For accelerator application this is highly necessary, otherwise the accelerator tuning and optimization becomes very difficult or even impossible. Already the beam transport becomes difficult for a noisy beam, because space charge compensation can be destroyed (at least partially). Furthermore a noisy dc-beam results in some rf-buckets which might be even empty.

  20. The ASY-EOS Experiment at GSI

    NASA Astrophysics Data System (ADS)

    Russotto, P.; Chartier, M.; Cozma, M. D.; De Filippo, E.; Le Fèvre, A.; Gannon, S.; Gašparić, I.; Kiš, M.; Kupny, S.; Leifels, Y.; Lemmon, R. C.; Li, Q.; Łukasik, J.; Marini, P.; Pawłowski, P.; Trautmann, W.; Acosta, L.; Adamczyk, M.; Al-Ajlan, A.; Al-Garawi, M.; Al-Homaidhi, S.; Amorini, F.; Auditore, L.; Aumann, T.; Ayyad, Y.; Baran, V.; Basrak, Z.; Bassini, R.; Benlliure, J.; Boiano, C.; Boisjoli, M.; Boretzky, K.; Brzychczyk, J.; Budzanowski, A.; Cardella, G.; Cammarata, P.; Chajecki, Z.; Chbihi, A.; Colonna, M.; Czech, B.; Di Toro, M.; Famiano, M.; Greco, V.; Grassi, L.; Guazzoni, C.; Guazzoni, P.; Heil, M.; Heilborn, L.; Introzzi, R.; Isobe, T.; Kezzar, K.; Krasznahorkay, A.; Kurz, N.; La Guidara, E.; Lanzalone, G.; Lasko, P.; Lombardo, I.; Lynch, W. G.; Matthews, Z.; May, L.; Minniti, T.; Mostazo, M.; Pagano, A.; Papa, M.; Pirrone, S.; Pleskac, R.; Politi, G.; Porto, F.; Reifarth, R.; Reisdorf, W.; Riccio, F.; Rizzo, F.; Rosato, E.; Rossi, D.; Santoro, S.; Simon, H.; Skwirczynska, I.; Sosin, Z.; Stuhl, L.; Trifirò, A.; Trimarchi, M.; Tsang, M. B.; Verde, G.; Veselsky, M.; Vigilante, M.; Wieloch, A.; Wigg, P.; Wolter, H. H.; Wu, P.; Yennello, S.; Zambon, P.; Zetta, L.; Zoric, M.

    2016-05-01

    The elliptic-flow ratio of neutrons with respect to protons or light complex particles in reactions of heavy ions at pre-relativistic energies has been proposed as an observable sensitive to the strength of the symmetry term of the nuclear equation of state at supra-saturation densities. In the ASY-EOS experiment at the GSI laboratory, flows of neutrons and light charged particles were measured for 197Au+197Au collisions at 400 MeV/nucleon. Flow results obtained for the Au+Au system, in comparison with predictions of the UrQMD transport model, confirm the moderately soft to linear density dependence of the symmetry energy deduced from the earlier FOPI-LAND data.

  1. A Finite Element Analysis for Predicting the Residual Compressive Strength of Impact-Damaged Sandwich Panels

    NASA Technical Reports Server (NTRS)

    Ratcliffe, James G.; Jackson, Wade C.

    2008-01-01

    A simple analysis method has been developed for predicting the residual compressive strength of impact-damaged sandwich panels. The method is tailored for honeycomb core-based sandwich specimens that exhibit an indentation growth failure mode under axial compressive loading, which is driven largely by the crushing behavior of the core material. The analysis method is in the form of a finite element model, where the impact-damaged facesheet is represented using shell elements and the core material is represented using spring elements, aligned in the thickness direction of the core. The nonlinear crush response of the core material used in the analysis is based on data from flatwise compression tests. A comparison with a previous analysis method and some experimental data shows good agreement with results from this new approach.

  2. A Finite Element Analysis for Predicting the Residual Compression Strength of Impact-Damaged Sandwich Panels

    NASA Technical Reports Server (NTRS)

    Ratcliffe, James G.; Jackson, Wade C.

    2008-01-01

    A simple analysis method has been developed for predicting the residual compression strength of impact-damaged sandwich panels. The method is tailored for honeycomb core-based sandwich specimens that exhibit an indentation growth failure mode under axial compression loading, which is driven largely by the crushing behavior of the core material. The analysis method is in the form of a finite element model, where the impact-damaged facesheet is represented using shell elements and the core material is represented using spring elements, aligned in the thickness direction of the core. The nonlinear crush response of the core material used in the analysis is based on data from flatwise compression tests. A comparison with a previous analysis method and some experimental data shows good agreement with results from this new approach.

  3. Logging damage to residual trees following partial cutting in a green ash-sugarberry stand in the Mississippi Delta

    Treesearch

    James S. Meadows

    1993-01-01

    Partial cutting in bottomland hardwoods to control stand density and species composition sometimes results in logging damage to the lower bole and/or roots of residual trees. If severe, logging damage may lead to a decline in tree vigor, which may subsequently stimulate the production of epicormic branches, causing a decrease in bole quality and an eventual loss in...

  4. Logging Damage to Residual Trees Following Partial Cutting in a Green Ash-Sugarberry Stand in the Mississippi Delta

    Treesearch

    James S. Meadows

    1993-01-01

    Partial cutting in bottomland hardwoods to control stand density and species composition sometimes results in logging damage to the lower bole and/or roots of residual trees. If severe, logging damage may lead to a decline in tree vigor, which may subsequently stimulate the production of epicormic branches, causing a decrease in bole quality and an eventual loss in...

  5. Search for DNA damage by human alkyladenine DNA glycosylase involves early intercalation by an aromatic residue.

    PubMed

    Hendershot, Jenna M; O'Brien, Patrick J

    2017-09-29

    DNA repair enzymes recognize and remove damaged bases that are embedded in the duplex. To gain access, most enzymes use nucleotide flipping, whereby the target nucleotide is rotated 180° into the active site. In human alkyladenine DNA glycosylase (AAG), the enzyme that initiates base excision repair of alkylated bases, the flipped-out nucleotide is stabilized by intercalation of the side chain of tyrosine 162 that replaces the lesion nucleobase. Previous kinetic studies provided evidence for the formation of a transient complex that precedes the stable flipped-out complex, but it is not clear how this complex differs from nonspecific complexes. We used site-directed mutagenesis and transient-kinetic approaches to investigate the timing of Tyr(162) intercalation for AAG. The tryptophan substitution (Y162W) appeared to be conservative, because the mutant protein retained a highly favorable equilibrium constant for flipping the 1,N(6)-ethenoadenine (ϵA) lesion, and the rate of N-glycosidic bond cleavage was identical to that of the wild-type enzyme. We assigned the tryptophan fluorescence signal from Y162W by removing two native tryptophan residues (W270A/W284A). Stopped-flow experiments then demonstrated that the change in tryptophan fluorescence of the Y162W mutant is extremely rapid upon binding to either damaged or undamaged DNA, much faster than the lesion-recognition and nucleotide flipping steps that were independently determined by monitoring the ϵA fluorescence. These observations suggest that intercalation by this aromatic residue is one of the earliest steps in the search for DNA damage and that this interaction is important for the progression of AAG from nonspecific searching to specific-recognition complexes. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  6. Relevance of impacter shape to nonvisible damage and residual tensile strength of a thick graphite/epoxy laminate

    NASA Technical Reports Server (NTRS)

    Poe, Clarence C., Jr.

    1991-01-01

    A study was made to determine the relevance of impacter shape to nonvisible damage and tensile residual strength of a 36 mm thick graphite/epoxy motor case. The shapes of the impacters were as follows: 12.7 mm and 25.4 mm diameter hemispheres, a sharp corner, and a 6.3 mm diameter bolt-like rod. The investigation revealed that damage initiated when the contact pressure exceeded a critical level. However, the damage was not visible on the surface until an even higher pressure was exceeded. The impact energy to initiate damage or cause visible damage on the surface increased approximately with impacter diameter to the third power. The reduction in strength for nonvisible damage increased with increasing diameter, 9 and 30 percent for the 12.7 mm and 25.4 mm diameter hemispheres, respectively. The corner impacter made visible damage on the surface for even the smallest impact energy. The rod impacter acted like a punch and sliced through the composite. Even so, the critical level of pressure to initiate damage was the same for the rod and hemispherical impacters. Factors of safety for nonvisible damage increased with increasing kinetic energy of impact. The effects of impacter shape on impact force, damage size, damage visibility, and residual tensile strength were predicted quite well assuming Hertzian contact and using maximum stress criteria and a surface crack analysis.

  7. Proton microscopy at GSI and FAIR

    SciTech Connect

    Merrill, Frank E; Mariam, Fesseha G; Golubev, A A; Turtikov, V I; Varentsov, D

    2009-01-01

    Proton radiography was invented in the 1990's at Los Alamos National Laboratory (LANL) as a diagnostic to study dynamic material properties under extreme pressures, strain and strain rate. Since this time hundreds of dynamic proton radiography experiments have been performed at LANL and facilities have been commissioned at the Institute for Theoretical and Experimental Physics (ITEP) in Russia for similar applications in dynamic material studies. Recently an international collaboration was formed to develop a new proton radiography capability for the study of dynamic material properties at the Facility for Anti-proton and Ion Research (FAIR) located at Gesellschaft fuer Schwerionenforschung (GSI) in Darmstadt, Germany. This new Proton microscope for FAIR (PRIOR) will provide radiographic imaging of dynamic systems with unprecedented spatial, temporal and density resolution, resulting in a window for understanding dynamic material properties at new length scales. These dynamic experiments will be driven with many energy sources including heavy ions, high explosives and lasers. The design of the proton microscope and expected radiographic performance is presented.

  8. Conceptualizing a Genomics Software Institute (GSI).

    PubMed

    Gilbert, Jack A; Catlett, Charlie; Desai, Narayan; Knight, Rob; White, Owen; Robbins, Robert; Sankaran, Rajesh; Sansone, Susanna-Assunta; Field, Dawn; Meyer, Folker

    2012-03-19

    Microbial ecology has been enhanced greatly by the ongoing 'omics revolution, bringing half the world's biomass and most of its biodiversity into analytical view for the first time; indeed, it feels almost like the invention of the microscope and the discovery of the new world at the same time. With major microbial ecology research efforts accumulating prodigious quantities of sequence, protein, and metabolite data, we are now poised to address environmental microbial research at macro scales, and to begin to characterize and understand the dimensions of microbial biodiversity on the planet. What is currently impeding progress is the need for a framework within which the research community can develop, exchange and discuss predictive ecosystem models that describe the biodiversity and functional interactions. Such a framework must encompass data and metadata transparency and interoperation; data and results validation, curation, and search; application programming interfaces for modeling and analysis tools; and human and technical processes and services necessary to ensure broad adoption. Here we discuss the need for focused community interaction to augment and deepen established community efforts, beginning with the Genomic Standards Consortium (GSC), to create a science-driven strategic plan for a Genomic Software Institute (GSI).

  9. Conceptualizing a Genomics Software Institute (GSI)

    PubMed Central

    Gilbert, Jack A.; Catlett, Charlie; Desai, Narayan; Knight, Rob; White, Owen; Robbins, Robert; Sankaran, Rajesh; Sansone, Susanna-Assunta; Field, Dawn; Meyer, Folker

    2012-01-01

    Microbial ecology has been enhanced greatly by the ongoing ‘omics revolution, bringing half the world's biomass and most of its biodiversity into analytical view for the first time; indeed, it feels almost like the invention of the microscope and the discovery of the new world at the same time. With major microbial ecology research efforts accumulating prodigious quantities of sequence, protein, and metabolite data, we are now poised to address environmental microbial research at macro scales, and to begin to characterize and understand the dimensions of microbial biodiversity on the planet. What is currently impeding progress is the need for a framework within which the research community can develop, exchange and discuss predictive ecosystem models that describe the biodiversity and functional interactions. Such a framework must encompass data and metadata transparency and interoperation; data and results validation, curation, and search; application programming interfaces for modeling and analysis tools; and human and technical processes and services necessary to ensure broad adoption. Here we discuss the need for focused community interaction to augment and deepen established community efforts, beginning with the Genomic Standards Consortium (GSC), to create a science-driven strategic plan for a Genomic Software Institute (GSI). PMID:22675605

  10. Composite sandwich construction with syntactic foam core - A practical assessment of post-impact damage and residual strength

    NASA Technical Reports Server (NTRS)

    Hiel, C.; Dittman, D.; Ishai, O.

    1993-01-01

    An account is given of an inspection method that has been successfully used to assess the postimpact damage and residual strength of syntactic (glass microspheres in epoxy matrix) foam-core sandwich panels with hybrid (carbon and glass fiber-reinforced) composite skins, which inherently possess high damage tolerance. SEM establishes that the crushing of the microspheres is responsible for the absorption of most of the impact energy. Damage tolerance is a function of the localization of damage by that high impact energy absorption.

  11. Damage of composite structures: Detection technique, dynamic response and residual strength

    NASA Astrophysics Data System (ADS)

    Lestari, Wahyu

    2001-10-01

    Reliable and accurate health monitoring techniques can prevent catastrophic failures of structures. Conventional damage detection methods are based on visual or localized experimental methods and very often require prior information concerning the vicinity of the damage or defect. The structure must also be readily accessible for inspections. The techniques are also labor intensive. In comparison to these methods, health-monitoring techniques that are based on the structural dynamic response offers unique information on failure of structures. However, systematic relations between the experimental data and the defect are not available and frequently, the number of vibration modes needed for an accurate identification of defects is much higher than the number of modes that can be readily identified in the experiment. These motivated us to develop an experimental data based detection method with systematic relationships between the experimentally identified information and the analytical or mathematical model representing the defective structures. The developed technique use changes in vibrational curvature modes and natural frequencies. To avoid misinterpretation of the identified information, we also need to understand the effects of defects on the structural dynamic response prior to developing health-monitoring techniques. In this thesis work we focus on two type of defects in composite structures, namely delamination and edge notch like defect. Effects of nonlinearity due to the presence of defect and due to the axial stretching are studied for beams with delamination. Once defects are detected in a structure, next concern is determining the effects of the defects on the strength of the structure and its residual stiffness under dynamic loading. In this thesis, energy release rate due to dynamic loading in a delaminated structure is studied, which will be a foundation toward determining the residual strength of the structure.

  12. Impact damage resistance and residual property assessment of (0/+/-45/90)s SCS-6/Timetal 21S

    NASA Technical Reports Server (NTRS)

    Miller, Jennifer L.; Portanova, Marc A.; Johnson, W. Steven

    1995-01-01

    The impact damage resistance and residual mechanical properties of (0/ +/- 45/90)s SCS-6/Timetal 21S composites were evaluated. Both quasi-static indentation and drop-weight impact tests were used to investigate the impact behavior at two nominal energy levels (5.5 and 8.4 J) and determine the onset of internal damage. Through x-ray inspection, the extent of internal damage was characterized non-destructively. The composite strength and constant amplitude fatigue response were evaluated to assess the effects of the sustained damage. Scanning electron microscopy was used to characterize internal damage from impact in comparison to damage that occurs during mechanical loading alone. The effect of stacking sequence was examined by using specimens with the long dimension of the specimen both parallel (longitudinal) and perpendicular (transverse) to the 0 deg fiber direction. Damage in the form of longitudinal and transverse cracking occurred in all longitudinal specimens tested at energies greater than 6.3 J. Similar results occurred in the transverse specimens tested above 5.4 J. Initial load drop, characteristic of the onset of damage, occurred on average at 6.3 J in longitudinal specimens and at 5.0 J in transverse specimens. X-ray analysis showed broken fibers in the impacted region in specimens tested at the higher impact energies. At low impact energies, visible matrix cracking may occur, but broken fibers may not. Matrix cracking was noted along fiber swims and it appeared to depend on the surface quality of composite. At low impact energies, little damage has been incurred by the composite and the residual strength and residual life is not greatly reduced as compared to an undamaged composite. At higher impact energies, more damage occurred and a greater effect of the impact damage was observed.

  13. Experimental Investigations on Fatigue Damage and Residual Properties of Interacting Notched Woven E-Glass/Epoxy Composite

    NASA Astrophysics Data System (ADS)

    Bhaskara Rao, Pathakokila; Rama Krishna, Avasarala; Ramji, Koona; Satya Devi, Ambadipudi

    2015-10-01

    The interacting notched laminates of plain weave E-glass fiber reinforced with epoxy were fatigued at predetermined frequency in tension-tension to investigate the fatigue damage and residual properties. The results from stress-life curves summarize that damage growing around the notches due to stress concentration is the underlying cause for the variation in fatigue strengths among the geometrically different specimens considered. The residual strength and modulus decay with respect to cycle number at 50 % of the ultimate tensile strength were investigated. It is evident from the experimental data that the residual strength decreases with cycle number and increases due to redistribution of stress around the notches. The detailed study of the damage development under cyclic loads also explains the causes of modulus reduction for all the laminate geometries.

  14. S1219 residue of 53BP1 is phosphorylated by ATM kinase upon DNA damage and required for proper execution of DNA damage response

    SciTech Connect

    Lee, Haemi; Kwak, Hee-Jin; Cho, Il-taeg; Park, Seok Hee; Lee, Chang-Hun

    2009-01-02

    53BP1 is phosphorylated by the protein kinase ATM upon DNA damage. Even though several ATM phosphorylation sites in 53BP1 have been reported, those sites have little functional implications in the DNA damage response. Here, we show that ATM phosphorylates the S1219 residue of 53BP1 in vitro and that the residue is phosphorylated in cells exposed to ionizing radiation (IR). Transfection with siRNA targeting ATM abolished IR-induced phosphorylation at this residue, supporting the theory that this process is mediated by the kinase. To determine the functional relevance of this phosphorylation event, a U2OS cell line expressing S1219A mutant 53BP1 was established. IR-induced foci formation of MDC1 and {gamma}H2AX, DNA damage signaling molecules, was reduced in this cell line, implying that S1219 phosphorylation is required for recruitment of these molecules to DNA damage sites. Furthermore, overexpression of the mutant protein impeded IR-induced G2 arrest. In conclusion, we have shown that S1219 phosphorylation by ATM is required for proper execution of DNA damage response.

  15. S1219 residue of 53BP1 is phosphorylated by ATM kinase upon DNA damage and required for proper execution of DNA damage response.

    PubMed

    Lee, Haemi; Kwak, Hee-Jin; Cho, Il-taeg; Park, Seok Hee; Lee, Chang-Hun

    2009-01-02

    53BP1 is phosphorylated by the protein kinase ATM upon DNA damage. Even though several ATM phosphorylation sites in 53BP1 have been reported, those sites have little functional implications in the DNA damage response. Here, we show that ATM phosphorylates the S1219 residue of 53BP1 in vitro and that the residue is phosphorylated in cells exposed to ionizing radiation (IR). Transfection with siRNA targeting ATM abolished IR-induced phosphorylation at this residue, supporting the theory that this process is mediated by the kinase. To determine the functional relevance of this phosphorylation event, a U2OS cell line expressing S1219A mutant 53BP1 was established. IR-induced foci formation of MDC1 and gammaH2AX, DNA damage signaling molecules, was reduced in this cell line, implying that S1219 phosphorylation is required for recruitment of these molecules to DNA damage sites. Furthermore, overexpression of the mutant protein impeded IR-induced G2 arrest. In conclusion, we have shown that S1219 phosphorylation by ATM is required for proper execution of DNA damage response.

  16. Relevance of impacter shape to nonvisible damage and residual tensile strength of a thick graphite/epoxy laminate

    NASA Technical Reports Server (NTRS)

    Poe, C. C., Jr.

    1990-01-01

    A study was made to determine the relevance of impacter shape to nonvisible damage and tensile residual strength of a 36 mm (1.4 in.) thick graphite/epoxy motor case. The shapes of the impacters were as follows: 12.7 mm (0.5 in.) and 25.4 mm (1.0 in.) diameter hemispheres, a sharp corner, and a 6.3 mm (0.25 in.) diameter bolt-like rod. The investigation revealed that damage initiated when the contact pressure exceeded a critical level. However, the damage was not visible on the surface until an even higher pressure was exceeded. The damage on the surface consisted of a crater shaped like the impacter, and the damage below the surface consisted of broken fibers. The impact energy to initiate damage or cause visible damage on the surface increased approximately with impacter diameter to the third power. The reduction in strength for nonvisible damage increased with increasing diameter, 9 and 30 percent for the 12.7 mm (0.5 in.) and 25.4 mm (1.0 in.) diameter hemispheres, respectively. The corner impacter made visible damage on the surface for even the smallest impact energy. The rod impacter acted like a punch and sliced through the composite. Even so, the critical level of pressure to initiate damage was the same for the rod and hemispherical impacters. Factors of safety for nonvisible damage increased with increasing kinetic energy of impact. The effects of impacter shape on impact force, damage size, damage visibility, and residual tensile strength were predicted quite well assuming Hertzian contact and using maximum stress criteria and a surface crack analysis.

  17. Site reactivity in the free radicals induced damage to leucine residues: a theoretical study.

    PubMed

    Medina, M E; Galano, A; Alvarez-Idaboy, J R

    2015-02-21

    Several recent computational studies have tried to explain the observed selectivity in radical damage to proteins. In this work we use Density Functional Theory and Transition State Theory including tunnelling corrections, reaction path degeneracy, the effect of diffusion, and the role of free radicals to get further insights into this important topic. The reaction between a leucine derivative and free radicals of biological significance, in aqueous and lipid media, has been investigated. Both thermochemical and kinetic analyses, in both hydrophilic and hydrophobic environments, have been carried out. DPPH, ˙OOH, ˙OOCH3, ˙OOCH2Cl, ˙OOCHCl2 and ˙OOCHCH2 radicals do not react with the target molecule. The reactions are proposed to be kinetically controlled. The leucine gamma site was the most reactive for the reactions with ˙N3, ˙OOCCl3, ˙OCH3, ˙OCH2Cl, and ˙OCHCl2 radicals, with rate constants equal to 1.97 × 10(5), 3.24 × 10(4), 6.68 × 10(5), 5.98 × 10(6) and 8.87 × 10(8) M(-1) s(-1), respectively, in aqueous solution. The ˙Cl, ˙OH and ˙OCCl3 radicals react with leucine at the beta, gamma, and delta positions at rates close to the diffusion limit with the alpha position which is the slowest path and the most thermodynamically favored. The presented results confirm that the Bell-Evans-Polanyi principle does not apply for the reactions between amino acid residues and free radicals. Regarding the influence of the environment on the reactivity of the studied series of free radicals towards leucine residues, it is concluded that hydrophilic media slightly lower the reactivity of the studied radicals, compared to hydrophobic ones, albeit the trends in reactivity are very similar.

  18. Residual strength and crack propagation tests on C-130 airplane center wings with service-imposed fatigue damage

    NASA Technical Reports Server (NTRS)

    Snider, H. L.; Reeder, F. L.; Dirkin, W. J.

    1972-01-01

    Fourteen C-130 airplane center wings, each containing service-imposed fatigue damage resulting from 4000 to 13,000 accumulated flight hours, were tested to determine their fatigue crack propagation and static residual strength characteristics. Eight wings were subjected to a two-step constant amplitude fatigue test prior to static testing. Cracks up to 30 inches long were generated in these tests. Residual static strengths of these wings ranged from 56 to 87 percent of limit load. The remaining six wings containing cracks up to 4 inches long were statically tested as received from field service. Residual static strengths of these wings ranged from 98 to 117 percent of limit load. Damage-tolerant structural design features such as fastener holes, stringers, doublers around door cutouts, and spanwise panel splices proved to be effective in retarding crack propagation.

  19. Luminescence Studies of Residual Damage in Low-Dose Arsenic Implanted Silicon after High-Temperature Annealing

    NASA Astrophysics Data System (ADS)

    Sagara, Akihiko; Hiraiwa, Miori; Shibata, Satoshi; Sugie, Ryuichi; Yamada, Keiichi

    2011-01-01

    In order to prevent the degradation of device performance, it is necessary to detect and reduce residual damage remaining after ion implantation and annealing. In this study, we focused on the high-temperature annealing process after low-dose arsenic (As) implantation in silicon (Si) and evaluated the correlation of annealing conditions and damage by cathodoluminescence (CL) compared to Secondary Ion Mass Spectrometry (SIMS) and Junction Photo-Voltage (JPV) results. Increasing the annealing temperature with the high-heat-up rate, As profile and the sheet resistance didn't change. However, the intensity of the band-to-band transition increased with temperature. This implies the some kind of residual damage remains after low-temperature annealing and it is removed with increasing annealing temperature. On the other hand, with increasing the annealing time at 1200 °C, more As was piled-up at the SiO2/Si interface and the luminescence intensity decreased. We guess this piled-up As is inactive and it may create some kind of damage combined with the defects around the interface, and these damage types cause the suppression of the luminescence intensity. We concluded that the luminescence intensity reflects the various kinds of damage and optical characterization methods have a potential to evaluate defect evolution in annealing process.

  20. Effect of temperatures on impact damage and residual strength of CFRP composite laminates

    NASA Astrophysics Data System (ADS)

    Im, Kwang-Hee; Cha, Cheon-Seok; Park, Jae-Woung; Cha, Yong-Hun; Yang, In-Young; Jung, Jong-An

    2000-05-01

    In this paper, the effect of temperature variations (low and high temperatures) was experimentally studied on the impact damages of CFRP laminates. Composite laminates used for this experiment are CF/EPOXY orthotropic laminated plates with two-interfaces [06/906]s and [04/904]s, and CF/PEEK orthotropic laminated plates with two-interfaces [06/906]s. A steel ball launched by the air gun collides against CFRP laminates to generate impact damages. With impact-damaged specimens, nondestructive evaluation (NDE) technique, such as a scanning acoustic microscope (SAM) was performed on the delamination-damaged samples to characterize damage growth using the SAM after impact damages according to the temperatures. Therefore, this study aims experimentally to present the interrelations between the impact energy and impact damages (i.e. delamination area and matrix) of CFRP laminates. (CF/EPOXY, CF/PEEK) subjected to FOD (foreign object damages) under low and high temperatures.

  1. Spin physics with anti-protons at GSI

    SciTech Connect

    Maggiora, Marco

    2005-10-26

    New insights on the nucleon structure can be obtained by means of the new p-barbeams, possibly polarised, foreseen at GSI; experimental asymmetries in Drell-Yan processes are a powerful tool to directly access transversity h1(x) without its convolution with fragmentation functions. Spin asymmetries in hyperon production and nucleonic form factors are discussed as well.

  2. Girls' Science Investigations (GSI) New Haven: Evaluating the Impact

    NASA Astrophysics Data System (ADS)

    Knodell, Claire; Fleming, Bonnie

    2009-05-01

    Girls' Science Investigations (GSI) New Haven seeks to empower the girls of today to shape the science of tomorrow. Funded by the NSF and Yale University and held at Yale, this program was designed to motivate, empower, and interest middle school girls in developing the skills required to pursue a career in science during a day-long investigation of the session's featured topic in science. Yale students and female professors act as mentors and guide younger girls through an environment for understanding and exploring various disciplines of science through hands-on activities in a laboratory setting. GSI strives to close the gap between males and females one action-packed Saturday at a time. This paper evaluates the success of the program. Student participant evaluations over the past 2 years coupled with student testimony and GSI coordinator, instructors', and volunteers' interviews allowed for an analysis of GSI's ability to inspire girls to pursue careers in science. The data indicates that a majority of girls who attended the program were more inclined to continue their study of science. The positive results are detailed in the following paper which points to the hands-on activities and enthusiasm of instructors as integral to the program's success.

  3. Prospects for triggering in experiment PAX at GSI

    NASA Astrophysics Data System (ADS)

    Kulikov, A.; Macharashvili, G.

    2007-02-01

    In experiment PAX, proposed for the new accelerator complex at GSI, investigations in the field of high-energy spin physics with the use of a polarized antiproton beam are planned. In this paper the possibilities for triggering are considered taking into account the PAX detector properties and a probable configuration of the trigger system is discussed for the first time.

  4. Simulation of balloon angioplasty in residually stressed blood vessels-Application of a gradient-enhanced fibre damage model.

    PubMed

    Polindara, César; Waffenschmidt, Tobias; Menzel, Andreas

    2016-08-16

    In this contribution we study the balloon angioplasty in a residually stressed artery by means of a non-local gradient-enhanced fibre damage model. The balloon angioplasty is a common surgical intervention used to extend or reopen narrowed blood vessels in order to restore the continuous blood flow in, for instance, atherosclerotic arteries. Inelastic, i.e. predominantly damage-related and elastoplastic processes are induced in the artery during its inflation resulting in an irreversible deformation. As a beneficial consequence, provided that the inelastic deformations do not exceed a specific limit, higher deformations can be obtained within the same pressure level and a continuous blood flow can be guaranteed. In order to study the mechanical response of the artery in this scenario, we make use of the non-local gradient-enhanced model proposed in Waffenschmidt et al. (2014). In this contribution, we extend this model to make use of an incompressible format in connection with a Q1Q1P0 finite element implementation. The residual stresses in the artery are also taken into account following the framework presented in Waffenschmidt (2015). From the results it becomes apparent that, when the artery is subjected to radial stresses beyond the physiological range, damage evolution is triggered in the collagen fibres. The impact of the residual stresses on the structural response and on the circumferential stress distribution along the thickness of the arterial wall is also studied. It is observed that the residual stresses have a beneficial effect on the mechanical response of the arterial wall.

  5. Towards the Handing of Cloud-Affected Infrared Radiances in the GSI

    NASA Technical Reports Server (NTRS)

    McCarty, William

    2012-01-01

    In the gridpoint statistical interpolation (GSI) data assimilation algorithm, only thermal infrared measurements determined to be uncontaminated by clouds are assimilated. Using this approach, typically only 19-29% of footprints are deemed to have no cloud affects through the measured spectra. This study will discuss the efforts underway at the Global Modeling and Assimilation Office (GMAO) at NASA Goddard Space Flight Center, in conjunction with the Joint Center for Satellite Data Assimilation (JCSDA), to actively assimilate these morecomplicated observations by using a graybody assumption. In the GSI, cloud top pressure and effective cloud amount are retrieved concurrently using a minimum residual method. This study will address the limitations and advantages of the technique and the modifications underway to the assimilation system to incorporate those two parameters into the radiative transfer forward operators and TL/AD calculations. Furthermore, it will explain the efforts underway to incorporate these parameters into the control vector so that they can be altered variationally as part of the minimization.

  6. Damage assessment and residual compression strength of thick composite plates with through-the-thickness reinforcements

    NASA Technical Reports Server (NTRS)

    Smith, Barry T.

    1990-01-01

    Damage in composite materials was studied with through-the-thickness reinforcements. As a first step it was necessary to develop new ultrasonic imaging technology to better assess internal damage of the composite. A useful ultrasonic imaging technique was successfully developed to assess the internal damage of composite panels. The ultrasonic technique accurately determines the size of the internal damage. It was found that the ultrasonic imaging technique was better able to assess the damage in a composite panel with through-the-thickness reinforcements than by destructively sectioning the specimen and visual inspection under a microscope. Five composite compression-after-impact panels were tested. The compression-after-impact strength of the panels with the through-the-thickness reinforcements was almost twice that of the comparable panel without through-the-thickness reinforcement.

  7. Damage assessment and residual compression strength of thick composite plates with through-the-thickness reinforcements

    NASA Technical Reports Server (NTRS)

    Smith, Barry T.; Farley, Gary L.; Maiden, Janice; Coogan, Dreux; Moore, Judith G.

    1991-01-01

    Damage in composite materials was studied with through-the-thickness reinforcements. As a first step it was necessary to develop new ultrasonic imaging technology to better assess internal damage of the composite. A useful ultrasonic imaging technique was successfully developed to assess the internal damage of composite panels. The ultrasonic technique accurately determines the size of the internal damage. It was found that the ultrasonic imaging technique was better able to assess the damage in composite panel with through-the-thickness reinforcements than by destructively sectioning the specimen and visual inspection under a microscope. Five composite compression-after-impact panels were tested. The compression-after-impact strength of the panels with the through-the-thickness reinforcements was almost twice that of the comparable panel without through-the-thickness reinforcement.

  8. Experiments on Superheavy Elements at the GSI Ship

    NASA Astrophysics Data System (ADS)

    Hofmann, S.

    2012-01-01

    An overview of present experimental investigation of superheavy elements is given. Using cold fusion reactions which are based on lead and bismuth targets, relatively neutron deficient isotopes of the elements from 107 to 112 were synthesized at GSI in Darmstadt, Germany, a neutron deficient isotope of element 113 at RIKEN in Wako, Japan. In hot fusion reactions of 48Ca projectiles with actinide targets more neutron rich isotopes of element 112 and new elements up to 118 were produced at FLNR in Dubna, Russia. Recently, part of these data which represent the first identification of nuclei located on the predicted island of SHEs, was confirmed in independent experiments. The measured data combined with theoretical results were used for estimating cross-sections for production of element 120 isotopes. Also evaluated were their decay properties. An experiment for searching of isotopes of element 120 is planned at the GSI SHIP.

  9. An integrated data acquisition and analysis system at GSI

    SciTech Connect

    Essel, H.G.; Hoffmann, J.; Richter, M.; Sohlbach, H.; Spreng )

    1989-10-01

    GOOSY, the GSI data acquisition and analysis system has been extended to handle experimental set-ups and data from heavy-ion experiments at high energies. A new front-end system has been designed and built. It is a VME based multi-processor system connected to CAMAC and FASTBUS via standard VSB. This system allows pre-analysis and filtering of the raw data. The architecture of the system is presented and a status report is given in this paper.

  10. Girls' Science Investigations (GSI) New Haven Curriculum and Educational Method

    NASA Astrophysics Data System (ADS)

    Hilton, Sheena; Fleming, Bonnie

    2009-05-01

    Girls' Science Investigations (GSI) New Haven is a program which aims at encouraging middle school girls to pursue careers in science. To accomplish this goal, each day at GSI features a different area of science; ``the material world,'' ``the chemical world,'' and ``the electromagnetic world'' are examples of the sessions held during the past two years. Every session features a short explanation of the science topic given by a volunteer and a variety of hands-on activities, which allow the girls to experiment with and absorb the concepts presented in the short presentations. Activities are selected based on their ability to visualize the concepts under study. The education philosophy of GSI is that if the students have the opportunity to perform science experiments themselves, rather than just watching others do it, and enjoy performing these experiments, then the students will be more confident in their ability to succeed in a scientific field. Thus, in addition to encouraging girls to learn as much science as they can, the volunteers work to ensure that the girls enjoy the program as well. By giving the girls the opportunity to explore science in a fun and exciting way, the girls begin to see themselves as capable of becoming scientists and are more inclined to pursue science in the future.

  11. Characterization of complex rock masses by combined borehole GSI and sonic logging

    NASA Astrophysics Data System (ADS)

    Sapigni, Michele; Agliardi, Federico; Crosta, Giovanni B.

    2015-04-01

    Reliable assessment of the strength and hydraulic properties of rock masses at depth is key to a number of geological, engineering and geohazard applications, including tunnelling, reservoir characterization and slope stability analysis. Rock mass investigations usually exploit direct geomechanical core logging and indirect geophysical techniques. A cost-effective and reliable characterisation of rock mass quality by direct investigation is often hampered by extremely variable lithological and structural conditions. On the other hand, available indirect methods correlating rock mass properties with geophysical investigation results apply to near-surface (upper few tens of meters in depth) and rely on rock mass descriptors poorly suitable for complex rocks (including deformed, weathered, or damaged rocks). Thus, there is a need to set up: 1) robust and versatile approaches to quantify (direct) rock mass descriptors suitable for complex geological conditions from drillcores; 2) statistically-sound relationships between such descriptors and rock mass properties obtained by (indirect) geophysical methods. We focus on the analysis of relationships between sonic P-wave velocity and rock mass quality described by the Geological Strength Index (GSI), both quantified in deep boreholes. The GSI is a suitable descriptor of rock mass structure and weathering, suitable for application to nearly all kind of rock types and geological conditions. We used site investigation data gathered to design a 9.2 km long headrace tunnel in a crystalline core complex of the central italian Alps. We analysed three boreholes up to 400 m deep in gneiss and meta-sedimentary rocks (including gypsum-anhydrite, marbles, decomposed carbonates) from which high quality HQ drillcores were extracted, allowing high-resolution geological and geomechanical logging. In the same boreholes, geophysical logging was performed using a "full-wave" sonic tool (transmitter operating at 27 kHz, receivers recording up

  12. Residual stand damage survey for three small tractors used in harvesting northern hardwoods

    Treesearch

    Neil K. Huyler; George D. Aiken; Chris B. LeDoux

    1994-01-01

    There have always been concerns about the impact of timber harvesting with conventional ground-based harvesting equipment on many parts of the forest ecosystem. One of these parts, which is easily measured, is the residual stand. The interest in small tractors (less than 60 horsepower) has increased in recent years because private landowners are concerned that large...

  13. Mapping residual stresses after foreign object damage using the contour method

    SciTech Connect

    Prime, M. B.; Martineau, R. L.

    2002-01-01

    A 51-mm thick plate of High-Strength Low-Alloy (HSLA-100) steel was impacted by a 6.4 mm diameter tungsten carbide sphere traveling at 2.2 km/sec. The projectile penetration left a 10 mm diameter and 12 mm deep crater. A residual stress map over a cross-section through the crater was measured by the contour method. The predominant feature of the stress map was a peak compressive stress of 900 MPa, or 1.3 times the yield strength, centered about 1.5 crater radii below the crater floor. The results were compared with an explicit finite element simulation of the impact event. The model has good agreement with the measured residual stresses. As part of the study, residual stresses in the as-received HSLA-100 plate were also measured and found to be a typical quenching stress distribution with peak compressive stress of about 165 MPa a few mm below the surface and tensile stress of 200 MPa in the center of the plate thickness.

  14. Assimilation of GPM GMI Rainfall Product with WRF GSI

    NASA Technical Reports Server (NTRS)

    Li, Xuanli; Mecikalski, John; Zavodsky, Bradley

    2015-01-01

    The Global Precipitation Measurement (GPM) is an international mission to provide next-generation observations of rain and snow worldwide. The GPM built on Tropical Rainfall Measuring Mission (TRMM) legacy, while the core observatory will extend the observations to higher latitudes. The GPM observations can help advance our understanding of precipitation microphysics and storm structures. Launched on February 27th, 2014, the GPM core observatory is carrying advanced instruments that can be used to quantify when, where, and how much it rains or snows around the world. Therefore, the use of GPM data in numerical modeling work is a new area and will have a broad impact in both research and operational communities. The goal of this research is to examine the methodology of assimilation of the GPM retrieved products. The data assimilation system used in this study is the community Gridpoint Statistical Interpolation (GSI) system for the Weather Research and Forecasting (WRF) model developed by the Development Testbed Center (DTC). The community GSI system runs in independently environment, yet works functionally equivalent to operational centers. With collaboration with the NASA Short-term Prediction Research and Transition (SPoRT) Center, this research explores regional assimilation of the GPM products with case studies. Our presentation will highlight our recent effort on the assimilation of the GPM product 2AGPROFGMI, the retrieved Microwave Imager (GMI) rainfall rate data for initializing a real convective storm. WRF model simulations and storm scale data assimilation experiments will be examined, emphasizing both model initialization and short-term forecast of precipitation fields and processes. In addition, discussion will be provided on the development of enhanced assimilation procedures in the GSI system with respect to other GPM products. Further details of the methodology of data assimilation, preliminary result and test on the impact of GPM data and the

  15. Study of SHE at the GSI-SHIP

    NASA Astrophysics Data System (ADS)

    Hofmann, S.

    2009-04-01

    An overview of present experimental investigation of superheavy elements is given. Using cold fusion reactions which are based on lead and bismuth targets, relatively neutron deficient isotopes of the elements from 107 to 113 were synthesized at GSI in Darmstadt, Germany, and/or at RIKEN in Wako, Japan. In hot fusion reactions of 48Ca projectiles with actinide targets more neutron rich isotopes of the elements from 112 to 116 and even 118 were produced at FLNR in Dubna, Russia. Recently, part of these data, which represent the first identification of nuclei located on the predicted island of SHEs, were confirmed in two independent experiments. The data are compared with theoretical descriptions.

  16. Assimilation of Dual-Polarimetric Radar Observations with WRF GSI

    NASA Technical Reports Server (NTRS)

    Li, Xuanli; Mecikalski, John; Fehnel, Traci; Zavodsky, Bradley; Srikishen, Jayanthi

    2014-01-01

    Dual-polarimetric (dual-pol) radar typically transmits both horizontally and vertically polarized radio wave pulses. From the two different reflected power returns, more accurate estimate of liquid and solid cloud and precipitation can be provided. The upgrade of the traditional NWS WSR-88D radar to include dual-pol capabilities will soon be completed for the entire NEXRAD network. Therefore, the use of dual-pol radar network will have a broad impact in both research and operational communities. The assimilation of dual-pol radar data is especially challenging as few guidelines have been provided by previous research. It is our goal to examine how to best use dual-pol radar data to improve forecast of severe storm and forecast initialization. In recent years, the Development Testbed Center (DTC) has released the community Gridpoint Statistical Interpolation (GSI) DA system for the Weather Research and Forecasting (WRF) model. The community GSI system runs in independently environment, yet works functionally equivalent to operational centers. With collaboration with the NASA Short-term Prediction Research and Transition (SPoRT) Center, this study explores regional assimilation of the dual-pol radar variables from the WSR-88D radars for real case storms. Our presentation will highlight our recent effort on incorporating the horizontal reflectivity (ZH), differential reflectivity (ZDR), specific differential phase (KDP), and radial velocity (VR) data for initializing convective storms, with a significant focus being on an improved representation of hydrometeor fields. In addition, discussion will be provided on the development of enhanced assimilation procedures in the GSI system with respect to dual-pol variables. Beyond the dual-pol variable assimilation procedure developing within a GSI framework, highresolution (=1 km) WRF model simulations and storm scale data assimilation experiments will be examined, emphasizing both model initialization and short-term forecast

  17. HST Solar array impact survey: revised damage laws and residue analysis

    NASA Astrophysics Data System (ADS)

    Drolshagen, G.; Carey, W. C.; McDonnell, J. A. M.; Stevenson, T. J.; Mandeville, J. C.; Berthoud, L.

    1997-05-01

    This report presents results of the analysis of impact features on the retrieved Hubble Space Telescope (HST) solar array and compares them to similar data from EURECA. The post-flight meteroid/debris investigation programmes included optical surveys of all outer surfaces, impact residue analyses and hypervelocity calibration tests on MLI and solar array samples. Observed crater sizes range from about 2 μm to 6-7 mm. On the HST solar array impact fluxes at the same crater pit diameter are higher than for EURECA for sizes exceeding about 200 μm while they are comparable for smaller sizes. Impact fluxes on EURECA and HST do both exceed the 6 face averaged fluxes on LDEF. The residue analyses which were performed for EURECA MLI and HST solar array samples proved very difficult due to the complexity of the targets and they produced somewhat inconclusive results. Some results of hypervelocity impact calibration tests are presented. A comparison between the measured impact data and the predictions of present flux models is given.

  18. Three-dimensional finite element analysis of residual magnetic field for ferromagnets under early damage

    NASA Astrophysics Data System (ADS)

    Yao, Kai; Shen, Kai; Wang, Zheng-Dao; Wang, Yue-Sheng

    2014-03-01

    In this study, 3D finite element analysis is presented by calculating the residual magnetic field signals of ferromagnets under the plastic deformation. The contour maps of tangential and normal RMF gradients are given, and the 3D effect is discussed. The results show that the tangential peak-peak amplitude and normal peak-vale amplitude are remarkably different in 2D and 3D simulations, but the tangential peak-peak width and normal peak-vale width are similar. Moreover, some key points are capable of capturing the plastic-zone shape, especially when the lift-off is small enough. The present study suggests an effective defect identification method with Metal magnetic memory (MMM) technique.

  19. Structural basis of damage recognition by thymine DNA glycosylase: Key roles for N-terminal residues

    PubMed Central

    Coey, Christopher T.; Malik, Shuja S.; Pidugu, Lakshmi S.; Varney, Kristen M.; Pozharski, Edwin; Drohat, Alexander C.

    2016-01-01

    Thymine DNA Glycosylase (TDG) is a base excision repair enzyme functioning in DNA repair and epigenetic regulation. TDG removes thymine from mutagenic G·T mispairs arising from deamination of 5-methylcytosine (mC), and it processes other deamination-derived lesions including uracil (U). Essential for DNA demethylation, TDG excises 5-formylcytosine and 5-carboxylcytosine, derivatives of mC generated by Tet (ten-eleven translocation) enzymes. Here, we report structural and functional studies of TDG82-308, a new construct containing 29 more N-terminal residues than TDG111-308, the construct used for previous structures of DNA-bound TDG. Crystal structures and NMR experiments demonstrate that most of these N-terminal residues are disordered, for substrate- or product-bound TDG82-308. Nevertheless, G·T substrate affinity and glycosylase activity of TDG82-308 greatly exceeds that of TDG111-308 and is equivalent to full-length TDG. We report the first high-resolution structures of TDG in an enzyme-substrate complex, for G·U bound to TDG82-308 (1.54 Å) and TDG111-308 (1.71 Å), revealing new enzyme-substrate contacts, direct and water-mediated. We also report a structure of the TDG82-308 product complex (1.70 Å). TDG82-308 forms unique enzyme–DNA interactions, supporting its value for structure-function studies. The results advance understanding of how TDG recognizes and removes modified bases from DNA, particularly those resulting from deamination. PMID:27580719

  20. Superheavy element chemistry at GSI status and perspectives

    NASA Astrophysics Data System (ADS)

    Schädel, M.

    2007-10-01

    Superheavy elements have been synthesized and chemically characterized one-atom-at-a-time up to element 108. Presently, the quest for identification and investigation of element 112 is one of the hottest topics in this field. The transactinide elements 104 to 108 are members of group 4 to 8 of the periodic table and element 112 belongs into group 12. For some of these elements detailed chemical properties have been revealed which show stunning deviations from simple extrapolations within their respective group while others exhibit great similarities with their lighter homologues. All presently known chemical properties of seaborgium (Sg, element 106) — the heaviest element whose behavior was investigated in aqueous solution — and hassium (Hs, element 108) were obtained in experiments performed at the GSI in large international collaborations. Recently, the highly efficient and very clean separation of Hs was applied for nuclear studies of various Hs nuclides investigating their cross section and their nuclear decay properties in the region of the N=162 neutron shell. To overcome certain limitations of the presently used on-line chemical separations the new TransActinide Separator and Chemistry Apparatus (TASCA) — with a gas-filled recoil separator as a front-end tool — was designed and built at the GSI in a collaborative effort. Presently in its commissioning phase, TASCA shall be a key instrument for a big leap into quantitatively and qualitatively new experiments in the region of superheavy elements.

  1. Relieved residual damage in the hematopoietic system of mice rescued by radiation-induced adaptive response (Yonezawa Effect)

    PubMed Central

    Wang, Bing; Tanaka, Kaoru; Ninomiya, Yasuharu; Maruyama, Kouichi; VarèS, Guillaume; Eguchi-Kasai, Kiyomi; Nenoi, Mitsuru

    2013-01-01

    Existence of adaptive response (AR) was previously demonstrated in C57BL/6J mice. Irradiations were performed by delivering a priming low dose of X-rays (0.50 Gy) in combination with a challenge high dose of accelerated carbon or neon ion particles. AR was characterized by significantly decreased mortality in the 30-day survival test. This mouse AR model (‘Yonezawa Effect’) was originally established by using X-rays as both the priming and challenge irradiations. The underlying mechanism was due to radio-resistance occurring in blood-forming tissues. In this study, we verified the existence of AR and further investigated residual damage in the hematopoietic system in surviving animals. Results showed that the priming low dose of X-rays could relieve the detrimental effects on the hematopoietic system. We observed both an improvement in the blood platelet count and the ratio of polychromatic erythrocytes (PCEs) to the sum of PCEs and normochromatic erythrocytes (NCEs) and a marked reduction of the incidences of micronucleated PCEs and micronucleated NCEs. These findings suggest that the priming low dose of low linear energy transfer (LET) X-rays induced a protective effect on the hematopoietic system, which may play an important role in both rescue from acute lethal damage (mouse killing) and prevention of late detrimental consequences (residual anhematopoiesis and delayed genotoxic effects) caused by exposure to a high challenge dose from low-LET (X-ray) or high-LET (carbon and neon ion) irradiations. These findings provide new knowledge of the characterization of the Yonezawa Effect by providing new insight into the mechanistic study of AR in vivo. PMID:22923746

  2. Nonlinear Response and Residual Strength of Damaged Stiffened Shells Subjected to Combined Loads

    NASA Technical Reports Server (NTRS)

    Starnes, James H., Jr.; Britt, Vicki O.; Rose, Cheryl A.; Rankin, Charles C.

    1996-01-01

    The results of an analytical study of the nonlinear response of stiffened fuselage shells with long cracks are presented. The shells are modeled with a hierarchical modeling strategy and analyzed with a nonlinear shell analysis code that maintains the shell in a nonlinear equilibrium state while the crack is grown. The analysis accurately accounts for global and local structural response phenomena. Fuselage skins, frames stringers and failsafe straps are included in the models. Results are presented for various combinations of internal pressure and mechanical bending, vertical shear and torsion loads, and the effects of crack orientation and location on the shell response are described. These results indicate that the nonlinear interaction between the in-plane stress resultants and the out-of-plane displacements near a crack can significantly affect the structural response of the shell, and the stress-intensity factors associated with a crack that are used to predict residual strength. The effects of representative combined loading conditions on the stress-intensity factors associated with a crack are presented. The effects of varying structural parameters on the stress-intensity factors associated with a crack, and on self-similar and non-self-similar crack-growth are also presented.

  3. Influence of Corrosion Damage on Prediction of Residual Strength Capacities - An Experimental Analysis

    NASA Astrophysics Data System (ADS)

    Appuhamy, Jayasinghe Mudalige Ruwan Sanjeewa; Ohga, Mitao; Kaita, Tatsumasa; Chun, Pang-Jo; Fujii, Katashi; Dissanayake, Ranjith

    Civil infrastructure systems are prone to age related deterioration due to the exposure to aggressive environmental conditions and inadequate maintenance, and often causes reduction of their carrying capacities. Designing these systems for a particular service life and maintaining them in a safe condition during their entire service life have been recognized as very critical issues worldwide. There have been many damage examples of older steel bridge structures due to corrosion around the world during past few decades and they intensified the importance of attention to the careful evaluation of existing structures for the feasibility of current usage and strengthening them by retrofitting some selected corroded members to ensure the public safety. Therefore, a simple and accurate method to calculate the remaining yield and tensile strength by using a concept of representative effective thickness with correlation of initial thickness and the maximum corroded depth is proposed in this study, based on the results of many tensile coupon tests conducted on corroded specimens cut from a steel girder used for about hundred years with severe corrosion. The proposed methodology revealed more accurate and reliable estimation for the maintenance management of existing corroded steel structures.

  4. Overview and Perspectives of SHE Research at GSI SHIP

    NASA Astrophysics Data System (ADS)

    Hofmann, Sigurd

    Theoretical studies present a quite detailed view of the stability of nuclei in the region of the heaviest elements. Three regions of increased stability exist. Two for deformed nuclei at proton and neutron numbers Z = 100 and N = 152 and at Z = 108 and N = 162. The third region is located at Z = 114, 120 or 126 and N = 184 for spherical nuclei due to closed shells or subshells. Experimentally, the existence of these regions of increased stability is established by synthesis of nuclei in cold fusion reactions using lead or bismuth targets and in hot fusion reactions based on actinide targets. Present experiments are trying to consolidate existing data and to explore the extension of the island of spherical nuclei into the direction of still heavier elements. The present status of experiments at the GSI SHIP is given as well as an outlook on investigations planned for the near future.

  5. TRB for HADES and FAIR experiments at GSI

    NASA Astrophysics Data System (ADS)

    Fröhlich, I.; Schrader, C.; Stroeble, H.; Stroth, J.; Tarantrola, A.; Kajetanowicz, M.; Korcyl, K.; Krzemień, W.; Palka, M.; Salabura, P.; TrȨBACZ, R.; Skott, P.; Traxler, M.

    2008-06-01

    TRB module is a multi-purpose Trigger and Readout Board with on-board DAQ functionality developed for the upgrade of the HADES experiment. It contains single computer chip (Etrax) running Linux and the 100 Mbit/s Ethernet interface. It has been orginally designed as the 128-channel Time to Digital Converter based on the HPTDC chip from CERN. The new version of TRB contains 2 Gbit/s optical link and interface connector (15 Gbit/s) implementing the add-on card concept and making the board more flexible. Moreover, FPGA chip (Xilinx, Virtex 4 LX 40) and TigerSharc DSP provide new computing resources which can be used to run on-line analysis algorithms. The TRB is proposed as a prototype of base readout module for the planned detector systems PANDA and CBM at the future FAIR facility at GSI-Darmstadt.

  6. TREATMENT OF HYDROCARBON, ORGANIC RESIDUE AND PRODUCTION CHEMICAL DAMAGE MECHANISMS THROUGH THE APPLICATION OF CARBON DIOXIDE IN NATURAL GAS STORAGE WELLS

    SciTech Connect

    Lawrence J. Pekot; Ron Himes

    2004-05-31

    Core specimens and several material samples were collected from two natural gas storage reservoirs. Laboratory studies were performed to characterize the samples that were believed to be representative of a reservoir damage mechanism previously identified as arising from the presence of hydrocarbons, organic residues or production chemicals. A series of laboratory experiments were performed to identify the sample materials, use these materials to damage the flow capacity of the core specimens and then attempt to remove or reduce the induced damage using either carbon dioxide or a mixture of carbon dioxide and other chemicals. Results of the experiments showed that pure carbon dioxide was effective in restoring flow capacity to the core specimens in several different settings. However, in settings involving asphaltines as the damage mechanism, both pure carbon dioxide and mixtures of carbon dioxide and other chemicals provided little effectiveness in damage removal.

  7. Community Service and User Support for the Gridpoint Statistical Interpolation (GSI) Data Assimilation and Analysis System

    NASA Astrophysics Data System (ADS)

    Shao, H.; Hu, M.; Stark, D.; Newman, K.; Zhou, C.; Derber, J.; Lueken, M.

    2013-12-01

    The Gridpoint Statistical Interpolation (GSI) system is a unified variational data assimilation and analysis system for both global and regional applications. It is currently used as a data assimilation system by various operational centers, including the National Oceanic and Atmospheric Administration (NOAA) (e.g., Global Forecasting System (GFS), North American Mesoscale (NAM) system, the Hurricane WRF (HWRF), and the RAPid Refresh (RAP) system), the National Aeronautics and Space Administration (NASA) (Goddard Earth Observing System (GEOS) Model), and the Air Force Weather Agency (AFWA). This analysis system is also used to generate certain analysis products, such as output from NOAA's GFS reanalysis and the Real-Time Mesoscale Analysis (RTMA) (e.g., 2m temperature, 10m winds gust, surface pressure and surface visibility). GSI can also be used to generate analyses for climate studies (e.g., ozone and sea surface temperature (SST) analyses) or assimilate non-'traditional' fields (e.g., aerosol data assimilation) for air quality studies (e.g., dust storms). Lately, an effort was initiated to use GSI for data assimilation throughout the entire atmosphere. One example of such an effort is the development of a data assimilation system for the Whole Atmosphere Model (WAM) at NCEP. Over the past few years, GSI has been transitioned to a community resource through a joint effort led by the Developmental Testbed Center (DTC), in collaboration with the National Centers for Environmental Prediction (NCEP) Environmental Modeling Center (EMC) and other GSI partners. The DTC is a distributed facility with a goal of serving as a bridge between the research and operational communities by transitioning the operational capability to a community resource and committing the contributions from the research community to the operational repository. The DTC has hosted four Community GSI tutorials and released five versions of the community GSI system with a corresponding User's Guide

  8. Recent Super Heavy Element Experiments at GSI-SHIP

    NASA Astrophysics Data System (ADS)

    Stoyer, M.; Hofmann, S.; Heinz, S.; Mann, R.; Maurer, J.; Khuyagbaatar, J.; Ackermann, D.; Antalic, S.; Barth, W.; Burkhard, H. G.; Comas, V. F.; Dahl, L.; Eberhardt, K.; Henderson, R.; Heredia, J. A.; Hessberger, F. P.; Kenneally, J.; Kindler, B.; Kojouharov, I.; Kratz, J. V.; Lang, R.; Leino, M.; Lommel, B.; Moody, K.; Munzenberg, G.

    2014-09-01

    The synthesis of element 116 (Lv) in fusion-evaporation reactions of a 48Ca beam with 248Cm targets was studied at the velocity filter SHIP of GSI in Darmstadt. At excitation energies of the compound nuclei of 40.9 MeV, four decay chains were measured, which were assigned to the isotope 292Lv, and one chain, which was assigned to 293Lv. Measured cross-sections of (3.4 + 2.7 -1.6) pb and (0.9 + 2.1 -0.7) pb, respectively, and decay data of the chains agree with data measured previously at the Flerov Laboratory of Nuclear Reactions in Dubna. We measured the velocity spectra of the 116 isotopes and transfer products which reveal the reaction type underlying the synthesis of the nuclei. The experience gained in this experiment will serve as a basis for future experiments to study still heavier elements at the velocity filter SHIP. Searches for element 120 in fusion-evaporation reactions of a 54Cr beam with 248Cm targets were studied later at SHIP and progress in the analysis will be discussed. The synthesis of element 116 (Lv) in fusion-evaporation reactions of a 48Ca beam with 248Cm targets was studied at the velocity filter SHIP of GSI in Darmstadt. At excitation energies of the compound nuclei of 40.9 MeV, four decay chains were measured, which were assigned to the isotope 292Lv, and one chain, which was assigned to 293Lv. Measured cross-sections of (3.4 + 2.7 -1.6) pb and (0.9 + 2.1 -0.7) pb, respectively, and decay data of the chains agree with data measured previously at the Flerov Laboratory of Nuclear Reactions in Dubna. We measured the velocity spectra of the 116 isotopes and transfer products which reveal the reaction type underlying the synthesis of the nuclei. The experience gained in this experiment will serve as a basis for future experiments to study still heavier elements at the velocity filter SHIP. Searches for element 120 in fusion-evaporation reactions of a 54Cr beam with 248Cm targets were studied later at SHIP and progress in the analysis will be

  9. Effects of damage and thermal residual stresses on the overall elastoplastic behavior of particle-reinforced metal matrix composites

    NASA Astrophysics Data System (ADS)

    Liu, Haitao

    The objective of the present study is to investigate damage mechanisms and thermal residual stresses of composites, and to establish the frameworks to model the particle-reinforced metal matrix composites with particle-matrix interfacial debonding, particle cracking or thermal residual stresses. An evolutionary interfacial debonding model is proposed for the composites with spheroidal particles. The construction of the equivalent stiffness is based on the fact that when debonding occurs in a certain direction, the load-transfer ability will lose in that direction. By using this equivalent method, the interfacial debonding problem can be converted into a composite problem with perfectly bonded inclusions. Considering the interfacial debonding is a progressive process in which the debonding area increases in proportion to external loading, a progressive interfacial debonding model is proposed. In this model, the relation between external loading and the debonding area is established using a normal stress controlled debonding criterion. Furthermore, an equivalent orthotropic stiffness tensor is constructed based on the debonding areas. This model is able to study the composites with randomly distributed spherical particles. The double-inclusion theory is recalled to model the particle cracking problems. Cracks inside particles are treated as penny-shape particles with zero stiffness. The disturbed stress field due to the existence of a double-inclusion is expressed explicitly. Finally, a thermal mismatch eigenstrain is introduced to simulate the inconsistent expansions of the matrix and the particles due to the difference of the coefficients of thermal expansion. Micromechanical stress and strain fields are calculated due to the combination of applied external loads and the prescribed thermal mismatch eigenstrains. For all of the above models, ensemble-volume averaging procedures are employed to derive the effective yield function of the composites. Numerical

  10. TREATMENT OF HYDROCARBON, ORGANIC RESIDUE AND PRODUCTION CHEMICAL DAMAGE MECHANISMS THROUGH THE APPLICATION OF CARBON DIOXIDE IN NATURAL GAS STORAGE WELLS

    SciTech Connect

    Lawrence J. Pekot

    2004-06-30

    Two gas storage fields were studied for this project. Overisel field, operated by Consumer's Energy, is located near the town of Holland, Michigan. Huntsman Storage Unit, operated by Kinder Morgan, is located in Cheyenne County, Nebraska near the town of Sidney. Wells in both fields experienced declining performance over several years of their annual injection/production cycle. In both fields, the presence of hydrocarbons, organic materials or production chemicals was suspected as the cause of progressive formation damage leading to the performance decline. Core specimens and several material samples were collected from these two natural gas storage reservoirs. Laboratory studies were performed to characterize the samples that were believed to be representative of a reservoir damage mechanism previously identified as arising from the presence of hydrocarbons, organic residues or production chemicals. A series of laboratory experiments were performed to identify the sample materials, use these materials to damage the flow capacity of the core specimens and then attempt to remove or reduce the induced damage using either carbon dioxide or a mixture of carbon dioxide and other chemicals. Results of the experiments showed that pure carbon dioxide was effective in restoring flow capacity to the core specimens in several different settings. However, in settings involving asphaltines as the damage mechanism, both pure carbon dioxide and mixtures of carbon dioxide and other chemicals provided little effectiveness in damage removal.

  11. Effects of moisture, residual thermal curing stresses and mechanical load on the damage development in quasi-isotropic laminates

    NASA Technical Reports Server (NTRS)

    Kriz, R. D.; Stinchcomb, W. W.; Tenney, D. R.

    1980-01-01

    Classical laminate theory and a finite element model were used to predict stress states prior to the first formation of damage in laminates fabricated from T/300/5208. Crack patterns characteristic of the laminate in a wet or dry condition were also predicted using a shear lag model. Development of edge damage was recorded and observed during the test by transferring an image of the damage from the edge surface on to a thin acetate sheet such that the damage imprinted could be immediately viewed on a microfiche card reader. Moisture was shown to significantly alter the interior and edge dry stress states due to swelling and a reduction of elastic properties and to reduce the transverse strength in 90 deg plies. A model was developed in order to predict changes in first ply failure laminate loads due to differences in stacking sequence together with a wet or dry environmental condition.

  12. Polyimide-Damage-Free, CMOS-Compatible Removal of Polymer Residues from Deep Reactive Ion Etching Passivation

    NASA Astrophysics Data System (ADS)

    Wu, W. J.; Zhu, T.; Liu, J. Q.; Fan, J.; Tu, L. C.

    2015-03-01

    A method for removal of passivation polymer residues from deep reactive ion-etching (DRIE) has been systematically investigated in this study. The method combines dry oxygen plasma ashing and conventional photoresist wet stripping. Samples were carefully examined by x-ray photoelectron spectroscopy (XPS), energy-dispersive x-ray spectroscopy (EDX), and study of surface morphology. XPS and EDX analysis showed that the polymer residues consisted mainly of C-O, CF x ( x = 1, 2, 3), and C-CF bonds. Optimized oxygen plasma ashing effectively removes most of the fluorocarbon content, except some nano-residues. Subsequent conventional wet stripping in organic solvents could eliminate these stubborn nanoparticles while dissolving the underlying photoresist. Excellent removal is apparent from scanning electron microscopy images. The fluorine content determined by EDX analysis showed that the residues were completely removed. The metal layers, oxide insulator layers, and the polyimide insulators function well after this critical surface treatment. The excellent results show this is an outstanding method for removal of DRIE passivation polymer residues for MEMS fabrication.

  13. Structural comparison of AP endonucleases from the exonuclease III family reveals new amino acid residues in human AP endonuclease 1 that are involved in incision of damaged DNA.

    PubMed

    Redrejo-Rodríguez, Modesto; Vigouroux, Armelle; Mursalimov, Aibek; Grin, Inga; Alili, Doria; Koshenov, Zhanat; Akishev, Zhiger; Maksimenko, Andrei; Bissenbaev, Amangeldy K; Matkarimov, Bakhyt T; Saparbaev, Murat; Ishchenko, Alexander A; Moréra, Solange

    2016-01-01

    Oxidatively damaged DNA bases are substrates for two overlapping repair pathways: DNA glycosylase-initiated base excision repair (BER) and apurinic/apyrimidinic (AP) endonuclease-initiated nucleotide incision repair (NIR). In the BER pathway, an AP endonuclease cleaves DNA at AP sites and 3'-blocking moieties generated by DNA glycosylases, whereas in the NIR pathway, the same AP endonuclease incises DNA 5' to an oxidized base. The majority of characterized AP endonucleases possess classic BER activities, and approximately a half of them can also have a NIR activity. At present, the molecular mechanism underlying DNA substrate specificity of AP endonucleases remains unclear mainly due to the absence of a published structure of the enzyme in complex with a damaged base. To identify critical residues involved in the NIR function, we performed biochemical and structural characterization of Bacillus subtilis AP endonuclease ExoA and compared its crystal structure with the structures of other AP endonucleases: Escherichia coli exonuclease III (Xth), human APE1, and archaeal Mth212. We found conserved amino acid residues in the NIR-specific enzymes APE1, Mth212, and ExoA. Four of these positions were studied by means of point mutations in APE1: we applied substitution with the corresponding residue found in NIR-deficient E. coli Xth (Y128H, N174Q, G231S, and T268D). The APE1-T268D mutant showed a drastically decreased NIR activity and an inverted Mg(2+) dependence of the AP site cleavage activity, which is in line with the presence of an aspartic residue at the equivalent position among other known NIR-deficient AP endonucleases. Taken together, these data show that NIR is an evolutionarily conserved function in the Xth family of AP endonucleases.

  14. Summary of a study to determine low-velocity impact damage and residual tension strength for a thick graphite/epoxy motor case

    NASA Technical Reports Server (NTRS)

    Poe, C. C., Jr.

    1990-01-01

    Impacters of various shapes and masses were dropped from various heights onto 36 mm (1.4 in.) thick graphite/epoxy cylinders, which represented filament wound cases (FWC) for the booster motors of the Space Shuttle. Insert solid propellant was cast into some of the cylinders. The cylinders were impacted numerous times around the circumference and then cut into 51 mm (2.0 in.) wide tension specimens, each containing an impact site. Four indenters were used: a sharp corner, two hemispheres, and a bolt-like rod. The diameters of the hemispheres were 12.7 mm mm (0.5 in.) and 25.4 mm (1.0 in.), and the diameter of the rod was 6.3 mm (0.25 in.). Impacts with the rod were simulated by pressing the rod against the face of specimens. For the hemispheres, the damage initiated beneath the surface at a critical contact pressure and was not visible on the surface until an even larger pressure was exceeded. The damage consisted of matrix cracking and broken fiber. The rod an corner made visible surface damage in all tests. For the hemispheres, the tension strength was reduced considerably before the damage was visible on the surface, 30 percent for the 25.4 mm (1.0 in.) diameter hemisphere and 10 percent for the 12.7 mm (0.5 in.) diameter hemisphere. Analytical methods were used to predict the damage and residual tension strength. A factor of safety to account for nonvisible damage was determined.

  15. Vectra GSI, Inc. low-level waste melter testing Phase 1 test report

    SciTech Connect

    Stegen, G.E.; Wilson, C.N.

    1996-02-21

    A multiphase program was initiated in 1994 to test commercially available melter technologies for the vitrification of the low-level waste (LLW) stream from defense wastes stored in underground tanks at the Hanford Site in southeastern Washington State. Vectra GSI, Inc. was one of seven vendors selected for Phase 1 of the melter demonstration tests using simulated LLW that were completed during fiscal year 1995. The attached report prepared by Vectra GSI, Inc. describes results of melter testing using slurry feed and dried feeds. Results of feed drying and prereaction tests using a fluid bed calciner and rotary dryer also are described.

  16. Effects of moisture, residual thermal curing stresses, and mechanical load on the damage development in quasi-isotropic laminates

    NASA Technical Reports Server (NTRS)

    Kriz, R. D.; Stinchcomb, W. W.

    1982-01-01

    This investigation demonstrates how moisture absorbed in (0/+ or - 45/90)s and (0/90/+ or - 45)s graphite epoxy laminates significantly alters the stress state and chronology of damage development along the laminate edge during static tension and tension-tension cyclic loading. Emphasis is placed on using reasonable approximations for wet and dry elastic properties, including out-of-plane properties (nu sub 23 and G sub 23), since these properties are required by finite element and shear lag models to predict the stress state at the laminate edge. Moisture was observed to alter the dry edge stress state in the 90-deg plies of the (0/+ or - 45/90)s laminate such that delaminations occurred at a lower load and transverse cracks occurred at a higher load. A model was developed which predicted the differences in loads required to initiate damage in the 90-deg plies of the two laminates in the wet and dry conditions. Although moisture can alter the chronology of damage development, the damage state in each laminate observed prior to fracture appeared to be independent of moisture content.

  17. Residual stocking not seriously reduced by logging damage from thinning of West Virginia cherry-maple stands

    Treesearch

    Neil I. Lamson; H. Clay Smith; Gary W. Miller

    1984-01-01

    In north-central West Virginia, unmanaged 60-year-old cherry-maple stands were thinned to 75, 60, and 45 percent residual stocking. Cut trees were skidded tree length by a rubber-tired skidder. Logging destroyed or severely bent over 22, 23, and 45 percent of the unmarked stems in the 75, 60, and 45 percent stocked plots. Because 99 percent of the destroyed and bent...

  18. Novel Functional Residues in the Core Domain of Histone H2B Regulate Yeast Gene Expression and Silencing and Affect the Response to DNA Damage

    PubMed Central

    Kyriss, McKenna N. M.; Jin, Yi; Gallegos, Isaura J.; Sanford, James A.; Wyrick, John J.

    2010-01-01

    Previous studies have identified novel modifications in the core fold domain of histone H2B, but relatively little is known about the function of these putative histone modification sites. We have mutated core modifiable residues that are conserved in Saccharomyces cerevisiae histone H2B and characterized the effects of the mutants on yeast silencing, gene expression, and the DNA damage response. We identified three histone H2B core modifiable residues as functionally important. We find that mutating H2B K49 in yeast confers a UV sensitivity phenotype, and we confirm that the homologous residue in human histone H2B is acetylated and methylated in human cells. Our results also indicate that mutating H2B K111 impairs the response to methyl methanesulfonate (MMS)-induced DNA lesions and disrupts telomeric silencing and Sir4 binding. In contrast, mutating H2B R102 enhances silencing at yeast telomeres and the HML silent mating loci and increases Sir4 binding to these regions. The H2B R102A mutant also represses the expression of endogenous genes adjacent to yeast telomeres, which is likely due to the ectopic spreading of the Sir complex in this mutant strain. We propose a structural model by which H2B R102 and K111 regulate the binding of the Sir complex to the nucleosome. PMID:20479120

  19. Estimates of the collision symmetry planes in HADES experiment at GSI

    NASA Astrophysics Data System (ADS)

    Zaytsev, A. S.; Selyuzhenkov, I.

    2017-01-01

    Estimate of the collision symmetry planes is a crucial part of the anisotropic flow analysis in heavy-ion collisions. HADES experiment at GSI has different possibilities for symmetry plane estimation. In this letter different methods of the symmetry plane resolution calculation are compared and the differences are explained in terms of non-flow contribution.

  20. A superconducting CW-LINAC for heavy ion acceleration at GSI

    NASA Astrophysics Data System (ADS)

    Barth, Winfried; Aulenbacher, Kurt; Basten, Markus; Dziuba, Florian; Gettmann, Viktor; Miski-Oglu, Maksym; Podlech, Holger; Yaramyshev, Stepan

    2017-03-01

    Recently the Universal Linear Accelerator (UNILAC) serves as a powerful high duty factor (25%) heavy ion beam accelerator for the ambitious experiment program at GSI. Beam time availability for SHE (Super Heavy Element)-research will be decreased due to the limitation of the UNILAC providing Uranium beams with an extremely high peak current for FAIR simultaneously. To keep the GSI-SHE program competitive on a high level and even beyond, a standalone superconducting continuous wave (100% duty factor) LINAC in combination with the upgraded GSI High Charge State injector is envisaged. In preparation for this, the first LINAC section (financed by HIM and GSI) will be tested with beam in 2017, demonstrating the future experimental capabilities. Further on the construction of an extended cryo module comprising two shorter Crossbar-H cavities is foreseen to test until end of 2017. As a final R&D step towards an entire LINAC three advanced cryo modules, each comprising two CH cavities, should be built until 2019, serving for first user experiments at the Coulomb barrier.

  1. Initial study of applying GSI to precisely use all observations for Rapid Update Analysis

    NASA Astrophysics Data System (ADS)

    Liu, M.; Hu, M.

    2016-12-01

    The Gridpoint Statistical Interpolation (GSI) Data Assimilation System has been developed as the analysis component of both global (GFS) and regional (RAP, NAM, HRRR) numerical weather forecast in NOAA/NCEP. The analysis results are tuned for improving the forecast skills instead of fitting closely to the observations. Thus, most of the analysis fields of GSI do not precisely reflect the observations and cannot be used by forecasters as a "truth" for nowcasting and verification. As an advanced operational data analysis system, GSI should be able to give analysis fields that precisely use all the observations to reflect the real atmospheric status. This study is to investigate how to calibrate the GSI to achieve this goal. To make the analysis close to the observations, the observation and background error covariance are modified and evaluated using regional ARW cases. The test shows that reducing background impact scale and decreasing background variance play the most important and sensitive role to push the analysis toward the observations. At the same time, it is found that the precise analysis of the observation needs to consider the impact of terrain or coast on temperature, surface pressure, and moisture. An algorithm is developed to deal with the impact of observations near coastline on analysis grid explicitly. Both ideal and real cases were conducted to test and verify the algorithm under different seasons and resolutions. Results show that the algorithm can distinguish the characteristics of coastal observations automatically, and then improve the analysis in the vicinity of shorlines.

  2. Development and Implementation of Dynamic Scripts to Execute Cycled GSI/WRF Forecasts

    NASA Technical Reports Server (NTRS)

    Zavodsky, Bradley; Srikishen, Jayanthi; Berndt, Emily; Li, Xuanli; Watson, Leela

    2014-01-01

    The Weather Research and Forecasting (WRF) numerical weather prediction (NWP) model and Gridpoint Statistical Interpolation (GSI) data assimilation (DA) are the operational systems that make up the North American Mesoscale (NAM) model and the NAM Data Assimilation System (NDAS) analysis used by National Weather Service forecasters. The Developmental Testbed Center (DTC) manages and distributes the code for the WRF and GSI, but it is up to individual researchers to link the systems together and write scripts to run the systems, which can take considerable time for those not familiar with the code. The objective of this project is to develop and disseminate a set of dynamic scripts that mimic the unique cycling configuration of the operational NAM to enable researchers to develop new modeling and data assimilation techniques that can be easily transferred to operations. The current version of the SPoRT GSI/WRF Scripts (v3.0.1) is compatible with WRF v3.3 and GSI v3.0.

  3. GSI experiments on the synthesis of superheavy elements

    NASA Astrophysics Data System (ADS)

    Heßberger, F. P.; Hofmann, S.; Ninov, V.; Armbruster, P.; Folger, H.; Lavrentev, A.; Leino, M. E.; Münzenberg, G.; Popeko, A. G.; Saro, S.; Stodel, Ch.; Yeremin, A. N.

    1998-02-01

    Evaporation residue production was investigated at SHIP in cold fusion reactions of Pb- and Bi-target nuclei with projectiles of elements between Ti (Z=22) and Se (Z=34) leading to compound nuclei ZCN=104-116. The isotopes 269110, 271110, 272111, and 277112 of the elements Z=110, Z=111 and Z=112 were unambiguously identified for the first time in bombardments of 208Pb, 209Bi with 62,64Ni and 70Zn. Excitation functions for 50Ti+208Pb and 58Fe+208Pb were measured with high precision, three new spontaneous fission (sf) activities 253104, 254104, 258106 were identified. A small α-decay branch of the even-even nucleus 256104 (bα≈0.003) was confirmed, allowing to estimate mass excesses Δmc2 for N-Z=48 nuclei up to 264Hs (Z=108). An analysis of the α-decay chains observed in a bombardment of 209Bi with 58Fe projectiles showed evidence for an isomeric state in 266Mt (Z=109). We further report on an attempt to produce element 116 and a second isotope of element 112 by the reactions 82Se+208Pb and 68Zn+208Pb, respectively.

  4. Pesticide residues, heavy metals, and DNA damage in sentinel oysters Crassostrea gigas from Sinaloa and Sonora, Mexico.

    PubMed

    Vázquez-Boucard, Celia; Anguiano-Vega, Gerardo; Mercier, Laurence; Rojas del Castillo, Emilio

    2014-01-01

    Pesticides and heavy metals were analyzed in sentinel Crassostrea gigas oysters placed in six aquaculture sites close to a contaminated agricultural region. Each site was sampled twice. Tests revealed the presence of organochlorine (OC) pesticides in the oysters at concentrations varying from 31.8 to 72.5 μg/kg for gamma-hexachlorocyclohexane (γ-HCH); from 1.2 to 3.1 μg/kg for dichlorodiphenyldichloroethylene (4,4-DDE); from 1.6 to 2.3 μg/kg for endosulfan I; and from 1.4 to 41.2 μg/kg for endosulfan II, as well as heavy metals in concentrations that exceeded Mexican tolerance levels (405.5 to 987.8 μg/g for zinc; 4.2 to 7.3 μg/g for cadmium; and 7.2 to 9.9 μg/g for lead). Significant levels of DNA damage in oyster hemocytes were also detected. There was a significant, positive correlation between genotoxic damage and concentration of nickel or the presence of endosulfan II. Cellular viability evaluated by cytotoxic analyses was found to be high at 80%. Marked inhibition in activity of acetylcholinesterase (AChE ) and induction of glutathione S-transferase (GST) activity was noted. Data demonstrated a significant relation between AChE activity inhibition and presence of endosulfan II, γ-HCH, copper, lead, and 4,4-DDE, as well as between AChE and GST activity at different sites.

  5. Microtubule-damaging drugs triggered bcl2 phosphorylation-requirement of phosphorylation on both serine-70 and serine-87 residues of bcl2 protein.

    PubMed

    Basu, A; Haldar, S

    1998-10-01

    Specifically anti-microtubule agents such as taxol, vincristine, vinblastine and dolastatin can trigger Bcl2 phosphorylation at G2-M phase of the cell cycle in malignant cells derived from a variety of human cancers. In this study, the status of Bcl2 phosphorylation was investigated in response to more antimicrotubule agents such as colchicine, colcemid or podophyllotoxin. Although these agents are not currently used for cancer therapy, they were able to trigger Bcl2 phosphorylation with simultaneous apoptosis in cancer cells. Previously, by using extensive site-directed mutagenesis studies we determined that mutation of serine-70 to alanine could not completely abrogate taxol induced Bcl2 phosphorylation. Studies reported here clearly indicate that serine-87 residue along with serine-70 of Bcl2 protein are necessary for microtubule damaging drug induced phosphorylation.

  6. A Large-scale Finite Element Model on Micromechanical Damage and Failure of Carbon Fiber/Epoxy Composites Including Thermal Residual Stress

    NASA Astrophysics Data System (ADS)

    Liu, P. F.; Li, X. K.

    2017-09-01

    The purpose of this paper is to study micromechanical progressive failure properties of carbon fiber/epoxy composites with thermal residual stress by finite element analysis (FEA). Composite microstructures with hexagonal fiber distribution are used for the representative volume element (RVE), where an initial fiber breakage is assumed. Fiber breakage with random fiber strength is predicted using Monte Carlo simulation, progressive matrix damage is predicted by proposing a continuum damage mechanics model and interface failure is simulated using Xu and Needleman's cohesive model. Temperature dependent thermal expansion coefficients for epoxy matrix are used. FEA by developing numerical codes using ANSYS finite element software is divided into two steps: 1. Thermal residual stresses due to mismatch between fiber and matrix are calculated; 2. Longitudinal tensile load is further exerted on the RVE to perform progressive failure analysis of carbon fiber/epoxy composites. Numerical convergence is solved by introducing the viscous damping effect properly. The extended Mori-Tanaka method that considers interface debonding is used to get homogenized mechanical responses of composites. Three main results by FEA are obtained: 1. the real-time matrix cracking, fiber breakage and interface debonding with increasing tensile strain is simulated. 2. the stress concentration coefficients on neighbouring fibers near the initial broken fiber and the axial fiber stress distribution along the broken fiber are predicted, compared with the results using the global and local load-sharing models based on the shear-lag theory. 3. the tensile strength of composite by FEA is compared with those by the shear-lag theory and experiments. Finally, the tensile stress-strain curve of composites by FEA is applied to the progressive failure analysis of composite pressure vessel.

  7. GSI experiments on the synthesis of superheavy elements

    SciTech Connect

    Hessberger, F. P.; Hofmann, S.; Ninov, V.; Armbruster, P.; Folger, H.; Muenzenberg, G.; Stodel, Ch.; Lavrentev, A.; Popeko, A. G.; Yeremin, A. N.; Leino, M. E.; Saro, S.

    1998-02-15

    Evaporation residue production was investigated at SHIP in cold fusion reactions of Pb- and Bi-target nuclei with projectiles of elements between Ti (Z=22) and Se (Z=34) leading to compound nuclei Z{sub CN}=104-116. The isotopes {sup 269}110, {sup 271}110, {sup 272}111, and {sup 277}112 of the elements Z=110, Z=111 and Z=112 were unambiguously identified for the first time in bombardments of {sup 208}Pb, {sup 209}Bi with {sup 62,64}Ni and {sup 70}Zn. Excitation functions for {sup 50}Ti+{sup 208}Pb and {sup 58}Fe+{sup 208}Pb were measured with high precision, three new spontaneous fission (sf) activities {sup 253}104, {sup 254}104, {sup 258}106 were identified. A small {alpha}-decay branch of the even-even nucleus {sup 256}104 (b{sub {alpha}}{approx_equal}0.003) was confirmed, allowing to estimate mass excesses {delta}mc{sup 2} for N-Z=48 nuclei up to {sup 264}Hs (Z=108). An analysis of the {alpha}-decay chains observed in a bombardment of {sup 209}Bi with {sup 58}Fe projectiles showed evidence for an isomeric state in {sup 266}Mt (Z=109). We further report on an attempt to produce element 116 and a second isotope of element 112 by the reactions {sup 82}Se+{sup 208}Pb and {sup 68}Zn+{sup 208}Pb, respectively.

  8. Logging damage

    Treesearch

    Ralph D. Nyland

    1989-01-01

    The best commercial logging will damage at least some residual trees during all forms of partial cutting, no matter how carefully done. Yet recommendations at the end of this Note show there is much that you can do to limit damage by proper road and trail layout, proper training and supervision of crews, appropriate equipment, and diligence.

  9. Residual rightward attentional bias after apparent recovery from right hemisphere damage: implications for a multicomponent model of neglect.

    PubMed Central

    Mattingley, J B; Bradshaw, J L; Bradshaw, J A; Nettleton, N C

    1994-01-01

    Unilateral neglect may be a multicomponent attentional disorder consisting of an initial automatic orienting of attention toward the ipsilesional side and a subsequent impairment in contralesionally reorienting attention, both of which are superimposed on a generalised reduction in attention resources. It has been hypothesised that patients' ability to reorient attention contralesionally may recover relatively quickly, but that the ipsilesional attention bias may be relatively persistent. This hypothesis was tested by consecutively examining 13 patients who had had a right hemisphere stroke, and who had left unilateral neglect. They were examined once shortly after the stroke and again 12 months later, using a battery of standard clinical and experimental tasks. Patients initially showed a strong and consistent rightward attentional bias in addition to a failure to reorient their attention leftward. After 12 months patients continued to show an abnormal ipsilesional attentional bias, though most were now able to fully reorient their attention toward the contralesional side. These results suggest that restitution of the capacity to reorient attention contralesionally may underlie the apparent recovery from clinical signs of unilateral neglect. The presence of a residual ipsilesional attentional bias in most patients, however, may, at least in part, account for the poor functional outcomes in some apparently "recovered" patients. Images PMID:8201332

  10. Influence of Source/Drain Residual Implant Lattice Damage Traps on Silicon Carbide Metal Semiconductor Field-Effect Transistor Drain I-V Characteristics

    NASA Astrophysics Data System (ADS)

    Adjaye, J.; Mazzola, M. S.

    4H-SiC n-channel power metal semiconductor field-effect transistors (MESFETs) with nitrogen n+-implanted source/drain ohmic contact regions, with and without p-buffer layer fabricated on semi-insulating substrates exhibited hysteresis in the drain I-V characteristics of both types of devices at 300 K and 480 K due to traps. However, thermal spectroscopic measurements could detect the traps only in the devices without p-buffer. Device simulation and optical admittance spectroscopy (OAS) are used to resolve the discrepancy in the initial experimental characterization results. Device simulations and OAS suggest that, in addition to the semi-insulating (SI) substrate traps, acceptor traps due to source/drain residual implant lattice damage contribute to the hysteresis observed in the drain I-V characteristics of the devices. Simulations suggest these traps are contained in the lateral straggle of the implanted source and drain regions since the drain current largely flows between the un-gated edges of the source and drain through the volume of lateral straggle traps. Since hysteresis in I-V curves is a manifestation of the presence of defects in devices and since defects degrade carrier mobility and hence device performance, efforts should be made to minimize the source/drain lateral straggle implant damage.

  11. Comparison of two freshwater turtle species as monitors of radionuclide and chemical contamination: DNA damage and residue analysis

    SciTech Connect

    Meyers-Schoene, L. ); Shugart, L.R.; Beauchamp, J.J.; Walton, B.T. )

    1993-08-01

    Two species of turtles that occupy different ecological niches were compared for their usefulness as monitors of freshwater ecosystems where both low-level radioactive and nonradioactive contaminants are present. The pond slider (Trachemys scripta) and common snapping turtle (Chelydra serpentina) were analyzed for the presence of [sup 90]Sr, [sup 137]Cs, [sup 60]Co, and Hg, radionuclides and chemicals known to be present at the contaminated site, and single-strand breaks in liver DNA. The integrity of the DNA was examined by the alkaline unwinding assay, a technique that detects strand breaks as a biological marker of possible exposure to genotoxic agents. This measure of DNA damage was significantly increased in both species of turtles at the contaminated site compared with turtles of the same species at a reference site, and shows that contaminant-exposed populations were under more severe genotoxic stress than those at the reference site. The level of strand breaks observed at the contaminated site was high and in the range reported for other aquatic species exposed to deleterious concentrations of genotoxic agents such as chemicals and ionizing radiation. Statistically significantly higher concentrations of radionuclides and Hg were detected in the turtles from the contaminated area. Mercury concentrations were significantly higher in the more carnivorous snapping turtle compared with the slider; however, both species were effective monitors of the contaminants.

  12. Assimilation of NUCAPS Retrieved Profiles in GSI for Unique Forecasting Applications

    NASA Technical Reports Server (NTRS)

    Berndt, Emily Beth; Zavodsky, Bradley; Srikishen, Jayanthi; Blankenship, Clay

    2015-01-01

    Hyperspectral IR profiles can be assimilated in GSI as a separate observation other than radiosondes with only changes to tables in the fix directory. Assimilation of profiles does produce changes to analysis fields and evidenced by: Innovations larger than +/-2.0 K are present and represent where individual profiles impact the final temperature analysis.The updated temperature analysis is colder behind the cold front and warmer in the warm sector. The updated moisture analysis is modified more in the low levels and tends to be drier than the original model background Analysis of model output shows: Differences relative to 13-km RAP analyses are smaller when profiles are assimilated with NUCAPS errors. CAPE is under-forecasted when assimilating NUCAPS profiles, which could be problematic for severe weather forecasting Refining the assimilation technique to incorporate an error covariance matrix and creating a separate GSI module to assimilate satellite profiles may improve results.

  13. Applications of the pulsed gas stripper technique at the GSI UNILAC

    NASA Astrophysics Data System (ADS)

    Scharrer, P.; Barth, W.; Bevcic, M.; Düllmann, Ch. E.; Gerhard, P.; Groening, L.; Horn, K. P.; Jäger, E.; Khuyagbaatar, J.; Krier, J.; Vormann, H.; Yakushev, A.

    2017-08-01

    In the frame of an upgrade program for the GSI UNILAC, preparing it for the use as an injector system for FAIR, a pulsed gas stripper cell was developed. It utilizes the required low duty cycle by applying a pulsed gas injection instead of a continuous gas inlet. The resulting lower gas consumption rate enables the use of low-Z gas targets over a wide range of stripper target thicknesses. The setup enables an increased flexibility for the accelerator by allowing the gas stripper to be used in time-sharing beam operation matching the capabilities of the GSI UNILAC like the acceleration of different ion beams in quasi-parallel operation. Measured charge state distributions of 238U, 50Ti, and CH3 beams on H2 and N2 gas highlight the benefits of the pulsed gas stripper cell for the accelerator operation and performance.

  14. Digital geological information delivery in the Geological Survey of Ireland (GSI)

    NASA Astrophysics Data System (ADS)

    Carter, Mary

    2014-05-01

    Digital information is delivered though a web portal with other spatial data from the Department of Communications Energy and Natural Resources. Individual viewers specific to major GSI topics can be access for a central web page on the GSI website. Most data is available to download from our data download site the Interactive Web Data Delivery System (IWDDS) which is interactively linked to our main viewers. More recent viewers include 3D viewers able to show the topography of a selected area, as well as dynamic legends for some layers and the ability to choose from a selection of basemaps and choose the transparency of each basemap. The hardware infrastructure for web delivery is based on virtual server technology and SAN technology, this maximises uptime and ease of administration as well as providing a flexible scaling of architecture as the need arises.

  15. Mechanism of 'GSI oscillations' in electron capture by highly charged hydrogen-like atomic ions

    SciTech Connect

    Krainov, V. P.

    2012-07-15

    We suggest a qualitative explanation of oscillations in electron capture decays of hydrogen-like {sup 140}Pr and {sup 142}Pm ions observed recently in an ion experimental storage ring (ESR) of Gesellschaft fuer Schwerionenforschung (GSI) mbH, Darmstadt, Germany. This explanation is based on the electron multiphoton Rabi oscillations between two Zeeman states of the hyperfine ground level with the total angular momentum F = 1/2. The Zeeman splitting is produced by a constant magnetic field in the ESR. Transitions between these states are produced by the second, sufficiently strong alternating magnetic field that approximates realistic fields in the GSI ESR. The Zeeman splitting amounts to only about 10{sup -5} eV. This allows explaining the observed quantum beats with the period 7 s.

  16. Real-time Aerosol Forecasting over North America using RAP-Chem and the GSI.

    NASA Astrophysics Data System (ADS)

    Pagowski, M.

    2015-12-01

    RAP-Chem is an implementation of WRF-Chem meteorology-chemistry model that is run daily at NOAA/ESRL over continental domain for air-quality forecasting. The chemical forecasts are combined with observations of species using three-dimensional variational data assimilation procedure implemented in the Gridpoint Statistical Interpolation (GSI). In the presentation we detail the method of the assimilation and show verification statistics of the model performance.

  17. Nuclear astrophysics experiments with stored, highly-charged ions at FRS-ESR at GSI

    SciTech Connect

    Scheidenberger, Christoph

    2010-08-12

    At the FRS-ESR complex of GSI a nuclear physics program with exotic nuclei has been established in last 18 years, which also addresses key questions and nuclear properties relevant in nuclear astrophysics. The paper summarizes production of exotic nuclei, lifetime studies of highly-charged ions, direct mass measurements and reactions at internal targets. A few comments on the analysis of two-body weak decays are given.

  18. Superheavy Element Studies with TASCA at GSI: Spectroscopy of Element 115 Decay Chains

    NASA Astrophysics Data System (ADS)

    Rudolph, Dirk

    Experimental campaigns on investigations of the superheavy elements 115, 117, 119, and 120 were conducted 2011 and 2012 at the gas-filled "TransActinide Separator and Chemistry Apparatus" (TASCA) at the GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany. Nuclear structure implications of first-ever α-photon coincidence spectroscopy on element 115 and its daughters obtained with the TASISpec set-up are discussed, likewise possible connections between decay chains associated with elements 115 and 117.

  19. Neutron dose measurements with the GSI ball at high-energy accelerators.

    PubMed

    Fehrenbacher, G; Gutermuth, F; Kozlova, E; Radon, T; Schuetz, R

    2007-01-01

    A moderator-type neutron monitor containing pairs of TLD 600/700 elements (Harshaw) modified with the addition of a lead layer (GSI ball) for the measurement of the ambient dose equivalent from neutrons at medium- and high-energy accelerators, is introduced in this work. Measurements were performed with the Gesellschaft für Schwerionenforschung (GSI) ball as well as with conventional polyethylene (PE) spheres at the high-energy accelerator SPS at European Organization for Nuclear Research [CERN (CERF)] and in Cave A of the heavy-ion synchrotron SIS at GSI. The measured dose values are compared with dose values derived from calculated neutron spectra folded with dose conversion coefficients. The estimated reading of the spheres calculated by means of the response functions and the neutron spectra is also included in the comparison. The analysis of the measurements shows that the PE/Pb sphere gives an improved estimate on the ambient dose equivalent of the neutron radiation transmitted through shielding of medium- and high-energy accelerators.

  20. Development and Implementation of Dynamic Scripts to Execute Cycled WRF/GSI Forecasts

    NASA Technical Reports Server (NTRS)

    Zavodsky, Bradley; Srikishen, Jayanthi; Berndt, Emily; Li, Quanli; Watson, Leela

    2014-01-01

    Automating the coupling of data assimilation (DA) and modeling systems is a unique challenge in the numerical weather prediction (NWP) research community. In recent years, the Development Testbed Center (DTC) has released well-documented tools such as the Weather Research and Forecasting (WRF) model and the Gridpoint Statistical Interpolation (GSI) DA system that can be easily downloaded, installed, and run by researchers on their local systems. However, developing a coupled system in which the various preprocessing, DA, model, and postprocessing capabilities are all integrated can be labor-intensive if one has little experience with any of these individual systems. Additionally, operational modeling entities generally have specific coupling methodologies that can take time to understand and develop code to implement properly. To better enable collaborating researchers to perform modeling and DA experiments with GSI, the Short-term Prediction Research and Transition (SPoRT) Center has developed a set of Perl scripts that couple GSI and WRF in a cycling methodology consistent with the use of real-time, regional observation data from the National Centers for Environmental Prediction (NCEP)/Environmental Modeling Center (EMC). Because Perl is open source, the code can be easily downloaded and executed regardless of the user's native shell environment. This paper will provide a description of this open-source code and descriptions of a number of the use cases that have been performed by SPoRT collaborators using the scripts on different computing systems.

  1. Use of MODIS Cloud Top Pressure to Improve Assimilation Yields of AIRS Radiances in GSI

    NASA Technical Reports Server (NTRS)

    Zavodsky, Bradley; Srikishen, Jayanthi

    2014-01-01

    Radiances from hyperspectral sounders such as the Atmospheric Infrared Sounder (AIRS) are routinely assimilated both globally and regionally in operational numerical weather prediction (NWP) systems using the Gridpoint Statistical Interpolation (GSI) data assimilation system. However, only thinned, cloud-free radiances from a 281-channel subset are used, so the overall percentage of these observations that are assimilated is somewhere on the order of 5%. Cloud checks are performed within GSI to determine which channels peak above cloud top; inaccuracies may lead to less assimilated radiances or introduction of biases from cloud-contaminated radiances.Relatively large footprint from AIRS may not optimally represent small-scale cloud features that might be better resolved by higher-resolution imagers like the Moderate Resolution Imaging Spectroradiometer (MODIS). Objective of this project is to "swap" the MODIS-derived cloud top pressure (CTP) for that designated by the AIRS-only quality control within GSI to test the hypothesis that better representation of cloud features will result in higher assimilated radiance yields and improved forecasts.

  2. Prognostic significance and relationship of worst lead residual ST segment elevation with myocardial damage assessed by cardiovascular MRI in myocardial infarction.

    PubMed

    Rommel, K P; Baum, A; Mende, M; Desch, S; Gutberlet, M; Schuler, G; Thiele, H; Eitel, I

    2014-08-01

    To investigate the relation of residual worst lead ST segment elevation (WL-STE) after ST segment myocardial infarction (STEMI) with infarct size and microvascular injury assessed by cardiovascular magnetic resonance (CMR) imaging. WL-STE in patients with acute reperfused STEMI has been shown to identify high risk patients for major adverse cardiovascular events (MACE). However, the relation of WL-STE with myocardial damage is unknown. In this multicentre study we analysed ECG data 90 min after primary percutaneous coronary intervention (PCI) in 763 STEMI patients. WL-STE was defined as the absolute magnitude of STE in the most affected lead on the post-PCI ECG. Patients were categorised into three groups (<1 mm, 1-2 mm, and ≥2 mm). CMR was performed within 1 week after infarction for comprehensive assessment of myocardial damage using a standardised protocol. The primary clinical endpoint was MACE defined as death, reinfarction, and new congestive heart failure within 12 months after infarction. WL-STE <1 mm, 1-2 mm, and ≥2 mm was present in 155 (20%), 328 (43%), and 280 (37%) patients, respectively. Myocardial damage determined by CMR demonstrated a graded relationship of infarct size (median (IQR) 13.3 (6.2-20.3)%LV vs 13.7 (7.6-21.3)%LV vs 22.5 (15.6-31.2)%LV, p<0.001), the myocardial salvage index (60.8 (37.0-84.5) vs 55.0 (36.6-73.9) vs 42.7 (26.2-58.2), p<0.001), and microvascular obstruction (0.0 (0.0-0.9)%LV vs 0.0 (0-1.0)%LV vs 1.2 (0.0-3.6)%LV, p<0.001) across the three groups. WL-STE ≥2 mm was strongly associated with MACE 12 month after infarction (HR 1.93, 95% CI 1.11 to 3.37; p=0.02). This largest CMR study to date correlating post-PCI WL-STE with markers of myocardial damage demonstrates that WL-STE is significantly associated with infarct size, myocardial salvage, microvascular obstruction, and MACE in a high risk STEMI population. NCT00712101. Published by the BMJ Publishing Group Limited. For permission to use (where

  3. Spectroscopy of η'-nucleus bound states at GSI and FAIR — very preliminary results and future prospects —

    NASA Astrophysics Data System (ADS)

    Fujioka, H.; Ayyad, Y.; Benlliure, J.; Brinkmann, K.-T.; Friedrich, S.; Geissel, H.; Gellanki, J.; Guo, C.; Gutz, E.; Haettner, E.; Harakeh, M. N.; Hayano, R. S.; Higashi, Y.; Hirenzaki, S.; Hornung, C.; Igarashi, Y.; Ikeno, N.; Itahashi, K.; Iwasaki, M.; Jido, D.; Kalantar-Nayestanaki, N.; Kanungo, R.; Knoebel, R.; Kurz, N.; Metag, V.; Mukha, I.; Nagae, T.; Nagahiro, H.; Nanova, M.; Nishi, T.; Ong, H. J.; Pietri, S.; Prochazka, A.; Rappold, C.; Reiter, M. P.; Rodríguez-Sánchez, J. L.; Scheidenberger, C.; Simon, H.; Sitar, B.; Strmen, P.; Sun, B.; Suzuki, K.; Szarka, I.; Takechi, M.; Tanaka, Y. K.; Tanihata, I.; Terashima, S.; Watanabe, Y. N.; Weick, H.; Widmann, E.; Winfield, J. S.; Xu, X.; Yamakami, H.; Zhao, J.

    2015-08-01

    The possible existence of η'-nucleus bound states has been put forward through theoretical and experimental studies. It is strongly related to the η' mass at finite density, which is expected to be reduced because of the interplay between the U A (1) anomaly and partial restoration of chiral symmetry. The investigation of the C( p, d) reaction at GSI and FAIR, as well as an overview of the experimental program at GSI and future plans at FAIR are discussed.

  4. A regional GSI-based EnKF system for the Rapid Refresh configuration: Tests for Satellite Radiance Observation

    NASA Astrophysics Data System (ADS)

    Zhu, Kefeng; Xue, Ming

    2015-04-01

    A regional ensemble Kalman filter data assimilation (EnKF) system based on the NCEP operational Grid-point Statistical Interpolation (GSI) system has been established for the target Rapid Refresh (RAP) applications. The EnKF system borrows the data processing and observation operators from the GSI system, and pre-calculates observation priors using the GSI. The filter is based on the serial ensemble square-root Kalman filter (EnSRF) and updates both the state vector and observation priors and its distributed memory parallelization is carried out at the state vector level. In this study, the impact of satellite radiance including AMSU, AIRS, MHS and HIRS within the established EnKF-RAP framework was examined. Testing is performed at the ~40 km grid spacing, and its performance is compared to the GSI system which uses three dimensional variation method. The performance is evaluated in terms of short-range (up to 18 hours) forecast errors verified again soundings. The assimilation of AMSU-A data improved the forecast accuracy for all the verified variables especially for the wind components; the assimilation of AIRS data greatly improved the forecast accuracy of relative humidity; when all the radiance data were assimilated, the forecast is the best. The forecast started from EnKF analysis is consistently better than from GSI analysis though the relative improvement is smaller than GSI. In additional, the configurations like bias correction and thinning for radiance assimilation within ENKF-RAP will be presented and discussed.

  5. Upgrading the GSI beamline microscope with a confocal fluorescence lifetime scanner to monitor charged particle induced chromatin decondensation in living cells

    NASA Astrophysics Data System (ADS)

    Abdollahi, Elham; Taucher-Scholz, Gisela; Durante, Marco; Jakob, Burkhard

    2015-12-01

    We report the upgrade of the GSI beamline microscope coupled to the linear accelerator UNILAC by a confocal FLIM scanner utilizing time correlated single photon counting technique (TCSPC). The system can now be used to address the radiation induced chromatin decondensation in more detail and with higher sensitivity compared to intensity based methods. This decondensation of heterochromatic areas is one of the early DNA damage responses observed after charged particle irradiation and might facilitate the further processing of the induced lesions. We describe here the establishment of different DNA dyes as chromatin compaction probes usable for quantification of the DNA condensation status in living cells utilizing lifetime imaging. In addition, we find an evidence of heterochromatic chromatin decondensation in ion irradiated murine chromocenters detected after subsequent fixation using FLIM measurements.

  6. Possible role of glutamine synthetase of the prokaryotic type (GSI-like) in nitrogen signaling in Medicago truncatula.

    PubMed

    Silva, Liliana S; Seabra, Ana R; Leitão, José N; Carvalho, Helena G

    2015-11-01

    Genes containing domains related to glutamine synthetase of the prokaryotic type (GSI-like) are widespread in higher plants, but their function is currently unknown. To gain insights into the possible role of GSI-like proteins, we characterized the GSI-like gene family of Medicago truncatula and investigated the functionality of the encoded proteins. M. truncatula contains two-expressed GSI-like genes, MtGSIa and MtGSIb, encoding polypeptides of 454 and 453 amino acids, respectively. Heterologous complementation assays of a bacterial glnA mutant indicate that the proteins are not catalytically functional for glutamine synthesis. Gene expression was investigated by qRT-PCR and western blot analysis in different organs of the plant and under different nitrogen (N) regimes, revealing that both genes are preferentially expressed in roots and root nodules, and that their expression is influenced by the N-status of the plant. Analysis of transgenic plants expressing MtGSI-like-promoter-gusA fusion, indicate that the two genes are strongly expressed in the root pericycle, and interestingly, the expression is enhanced at the sites of nodule emergence being particularly strong in specific cells located in front of the protoxylem poles. Taken together, the results presented here support a role of GSI-like proteins in N sensing and/or signaling, probably operating at the interface between perception of the N-status and the developmental processes underlying both root nodule and lateral root formation. This study indicates that GSI-like genes may represent a novel class of molecular players of the N-mediated signaling events.

  7. The symmetry energy at suprasaturation density and the ASY-EOS experiment at GSI

    NASA Astrophysics Data System (ADS)

    De Filippo, E.; Russotto, P.; Acosta, L.; Adamczyk, M.; Al-Ajlan, A.; Al-Garawi, M.; Al-Homaidhi, S.; Amorini, F.; Auditore, L.; Aumann, T.; Ayyad, Y.; Basrak, Z.; Benlliure, J.; Boisjoli, M.; Boretzky, K.; Brzychczyk, J.; Budzanowski, A.; Caesar, C.; Cardella, G.; Cammarata, P.; Chajecki, Z.; Chartier, M.; Chbihi, A.; Colonna, M.; Cozma, M. D.; Czech, B.; Di Toro, M.; Famiano, M.; Gannon, S.; Gašparić, I.; Grassi, L.; Guazzoni, C.; Guazzoni, P.; Heil, M.; Heilborn, L.; Introzzi, R.; Isobe, T.; Kezzar, K.; Kiš, M.; Krasznahorkay, A.; Kupny, S.; Kurz, N.; La Guidara, E.; Lanzalone, G.; Lasko, P.; Le Fèvre, A.; Leifels, Y.; Lemmon, R. C.; Li, Q. F.; Lombardo, I.; Łukasik, J.; Lynch, W. G.; Marini, P.; Matthews, Z.; May, L.; Minniti, T.; Mostazo, M.; Pagano, A.; Pagano, E. V.; Papa, M.; Pawłowski, P.; Pirrone, S.; Politi, G.; Porto, F.; Reviol, W.; Riccio, F.; Rizzo, F.; Rosato, E.; Rossi, D.; Santoro, S.; Sarantites, D. G.; Simon, H.; Skwirczynska, I.; Sosin, Z.; Stuhl, L.; Trautmann, W.; Trifirò, A.; Trimarchi, M.; Tsang, M. B.; Verde, G.; Veselsky, M.; Vigilante, M.; Wang, Yongjia; Wieloch, A.; Wigg, P.; Winkelbauer, J.; Wolter, H. H.; Wu, P.; Yennello, S.; Zambon, P.; Zetta, L.; Zoric, M.

    2017-03-01

    The ASY-EOS experiment at GSI laboratory measured the direct and elliptic flow of neutrons and light charged particles in the reaction 197Au+197 Au at 400 A MeV incident energy. The ratio of elliptic flow of neutrons with respect to that of the light charged particles was used as main experimental observable to probe the density dependence of the symmetry energy term of the nuclear equation of state. Results, obtained by comparison of the experimental data with the UrQMD model predictions, strongly support a moderately soft to linear density dependence of the symmetry energy at suprasaturation densities below 2ρ0.

  8. Study of she at GSI - Status and Perspectives for the Next Decade

    NASA Astrophysics Data System (ADS)

    Hessberger, F. P.

    2011-03-01

    An extensive program on synthesis of superheavy elements (SHE) and investigating their nuclear structure as well as their chemical properties has been performed at the UNILAC accelerator at GSI during the past three decades. Highlights of this research program were the identification of the new elements with atomic numbers Z = 107-112, detailed nuclear structure investigations and discovery of new K isomers in the transfermium region, first chemical characterization of element 108 (hassium) and identification of the deformed doubly magic nucleus 270Hs. Part of the latest results are presented and discussed. Current and prospected upgrades of the facility and the experimental set-ups are presented.

  9. The EXL experiment at FAIR and plans with the ESR at GSI

    SciTech Connect

    Kalantar-Nayestanaki, N.

    2011-10-28

    In this contribution, the physics program of the EXL experiment at FAIR-NuSTAR along with its experimental setup will be briefly outlined. This experiment aims to study the structure and the dynamics of radioactive nuclei which collide with light ions in inverse kinematics. On the way to the final measurements, several measurements have been proposed at the existing ESR at GSI with the purpose of understanding the detection systems for EXL and obtaining the first physics results in this type of experiments in a storage ring.

  10. Comparing symmetry energy predictions and recent constraints from the ASY-EOS experiment at GSI

    NASA Astrophysics Data System (ADS)

    Sammarruca, Francesca

    2017-04-01

    Predictions for the interaction part of the symmetry energy obtained from microscopic approaches based upon different foundations are reviewed and discussed in the light of recent updated constraints obtained from reaction observables in the ASY-EOS experiment at GSI. The discussion is then extended to the neutron skin thickness in 208Pb and its relation to the density derivatives of the symmetry energy at and below saturation density. With regard to the latter, the main point is to demonstrate the importance of proper consideration of the theoretical uncertainties of microscopic predictions in order to guide phenomenological analyses.

  11. Production of high current proton beams using complex H-rich molecules at GSI

    SciTech Connect

    Adonin, A. Barth, W.; Heymach, F.; Hollinger, R.; Vormann, H.; Yakushev, A.

    2016-02-15

    In this contribution, the concept of production of intense proton beams using molecular heavy ion beams from an ion source is described, as well as the indisputable advantages of this technique for operation of the GSI linear accelerator. The results of experimental investigations, including mass-spectra analysis and beam emittance measurements, with different ion beams (CH{sub 3}{sup +},C{sub 2}H{sub 4}{sup +},C{sub 3}H{sub 7}{sup +}) using various gaseous and liquid substances (methane, ethane, propane, isobutane, and iodoethane) at the ion source are summarized. Further steps to improve the ion source and injector performance with molecular beams are depicted.

  12. Determination of the mechanical parameters of rock mass based on a GSI system and displacement back analysis

    NASA Astrophysics Data System (ADS)

    Kang, Kwang-Song; Hu, Nai-Lian; Sin, Chung-Sik; Rim, Song-Ho; Han, Eun-Cheol; Kim, Chol-Nam

    2017-08-01

    It is very important to obtain the mechanical paramerters of rock mass for excavation design, support design, slope design and stability analysis of the underground structure. In order to estimate the mechanical parameters of rock mass exactly, a new method of combining a geological strength index (GSI) system with intelligent displacment back analysis is proposed in this paper. Firstly, average spacing of joints (d) and rock mass block rating (RBR, a new quantitative factor), surface condition rating (SCR) and joint condition factor (J c) are obtained on in situ rock masses using the scanline method, and the GSI values of rock masses are obtained from a new quantitative GSI chart. A correction method of GSI value is newly introduced by considering the influence of joint orientation and groundwater on rock mass mechanical properties, and then value ranges of rock mass mechanical parameters are chosen by the Hoek-Brown failure criterion. Secondly, on the basis of the measurement result of vault settlements and horizontal convergence displacements of an in situ tunnel, optimal parameters are estimated by combination of genetic algorithm (GA) and numerical simulation analysis using FLAC3D. This method has been applied in a lead-zinc mine. By utilizing the improved GSI quantization, correction method and displacement back analysis, the mechanical parameters of the ore body, hanging wall and footwall rock mass were determined, so that reliable foundations were provided for mining design and stability analysis.

  13. Numerical Simulation and RF Model Measurements of the New GSI IH-DTL

    NASA Astrophysics Data System (ADS)

    Krietenstein, B.; Weiland, T.; Ratzinger, U.; Tiede, R.; Minaev, S. A.

    1997-05-01

    Two IH drift tube cavities will be part of the new pre-stripper LINAC being under construction at the gsi.de>GSI accelerator facility in Darmstadt (Germany) in order to provide higher beam intensities. The first part of the cavity design process consisted of numerical electromagnetic simulations using MAFIA( Solution of M)axwell's equations using a Finite Integration Algorithm. Based on these calculations the tanks are under construction and a 1:5.88 scaled RF model was built to compare the results and to determine the exact drift tube geometry as well as to find optimum positions and shapes for the tuners. To accelerate the design process, an equivalent circuit model (ECM) is under construction, which will read its input parameters from MAFIA calculations. This paper describes the most important steps in the design process. It presents results for the MAFIA simulation, the rf model measurement the state of the ECM studies.

  14. Performance of upstream interaction region detectors for the FIRST experiment at GSI

    NASA Astrophysics Data System (ADS)

    Abou-Haidar, Z.; Agodi, C.; Alvarez, M. A. G.; Anelli, M.; Aumann, T.; Battistoni, G.; Bocci, A.; Böhlen, T. T.; Boudard, A.; Brunetti, A.; Carpinelli, M.; Cirrone, G. A. P.; Cortes-Giraldo, M. A.; Cuttone, G.; De Napoli, M.; Durante, M.; Fernández-García, J. P.; Finck, C.; Gallardo, M. I.; Golosio, B.; Iarocci, E.; Iazzi, F.; Ickert, G.; Introzzi, R.; Juliani, D.; Krimmer, J.; Kurz, N.; Labalme, M.; Leifels, Y.; Le F{èvre, A.; Leray, S.; Marchetto, F.; Monaco, V.; Morone, M. C.; Oliva, P.; Paoloni, A.; Patera, V.; Piersanti, L.; Pleskac, R.; Quesada, J. M.; Randazzo, N.; Romano, F.; Rossi, D.; Rosso, V.; Rousseau, M.; Sacchi, R.; Sala, P.; Sarti, A.; Schuy, C.; Sciubba, A.; Sfienti, C.; Simon, H.; Sipala, V.; Spiriti, E.; Stuttge, L.; Tropea, S.; Younis, H.

    2012-02-01

    The FIRST (Fragmentation of Ions Relevant for Space and Therapy) experiment at GSI has been designed to study carbon fragmentation, measuring 12C double differential cross sections (∂2σ/∂θ∂E) for different beam energies between 100 and 1000 MeV/u. The experimental setup integrates newly designed detectors in the, so called, Interaction Region around the graphite target. The Interaction Region upstream detectors are a 250 μm thick scintillator and a drift chamber optimized for a precise measurement of the ions interaction time and position on the target. In this article we review the design of the upstream detectors along with the preliminary results of the data taking performed on August 2011 with 400 MeV/u fully stripped carbon ion beam at GSI. Detectors performances will be reviewed and compared to those obtained during preliminary tests, performed with 500 MeV electrons (at the BTF facility in the INFN Frascati Laboratories) and 80 MeV/u protons and carbon ions (at the INFN LNS Laboratories in Catania).

  15. Use of MODIS Cloud Top Pressure to Improve Assimilation Yields of AIRS Radiances in GSI

    NASA Technical Reports Server (NTRS)

    Zavodsky, Bradley; Srikishen, Jayanthi

    2014-01-01

    Improvements to global and regional numerical weather prediction have been demonstrated through assimilation of data from NASA's Atmospheric Infrared Sounder (AIRS). Current operational data assimilation systems use AIRS radiances, but impact on regional forecasts has been much smaller than for global forecasts. Previously, it has been shown that cloud top designation associated with quality control procedures within the Gridpoint Statistical Interpolation (GSI) system used operationally by a number of Joint Center for Satellite Data Assimilation (JCSDA) partners may not provide the best representation of cloud top pressure (CTP). Because this designated CTP determines which channels are cloud-free and, thus, available for assimilation, ensuring the most accurate representation of this value is imperative to obtaining the greatest impact from satellite radiances. This paper examines the assimilation of hyperspectral sounder data used in operational numerical weather prediction by comparing analysis increments and numerical forecasts generated using operational techniques with a research technique that swaps CTP from the Moderate-resolution Imaging Spectroradiometer (MODIS) for the value of CTP calculated from the radiances within GSI.

  16. Towards detailed knowledge of atomic nuclei—the past, present and future of nuclear structure investigations at GSI

    NASA Astrophysics Data System (ADS)

    Gerl, J.; Gorska, M.; Wollersheim, H. J.

    2016-10-01

    Selected experimental nuclear structure physics results are presented which have been obtained at GSI since the mid 70ties employing the UNILAC and the SIS/FRS accelerator facility. It is shown how stable heavy-ion beams as well as radioactive isotope beams of this facility together with state-of-the-art instrumentation produced many discoveries and led to a multitude of important results covering many aspects of nuclear structure. Finally, we discuss the future directions of nuclear structure research at GSI with the FAIR/NUSTAR project.

  17. Facility for Antiproton and Ion Research, FAIR, at the GSI site

    SciTech Connect

    Rosner, Guenther

    2006-11-17

    FAIR is a new large-scale particle accelerator facility to be built at the GSI site in Germany. The research pursued at FAIR will cover a wide range of topics in nuclear and hadron physics, as well as high density plasma physics, atomic and antimatter physics, and applications in condensed matter physics and biology. The working horse of FAIR will be a 1.1km circumference double ring of rapidly cycling 100 and 300Tm synchrotrons, which will be used to produce high intensity secondary beams of short-lived radioactive ions or antiprotons. A subsequent suite of cooler and storage rings will deliver heavy ion and antiproton beams of unprecedented quality. Large experimental facilities are presently being designed by the NUSTAR, PANDA, PAX, CBM, SPARC, FLAIR, HEDgeHOB and BIOMAT collaborations.

  18. Lognormal Assimilation of Water Vapor in a WRF-GSI Cycled System

    NASA Astrophysics Data System (ADS)

    Fletcher, S. J.; Kliewer, A.; Jones, A. S.; Forsythe, J. M.

    2015-12-01

    Recent publications have shown the viability of both detecting a lognormally-distributed signal for water vapor mixing ratio and the improved quality of satellite retrievals in a 1DVAR mixed lognormal-Gaussian assimilation scheme over a Gaussian-only system. This mixed scheme is incorporated into the Gridpoint Statistical Interpolation (GSI) assimilation scheme with the goal of improving forecasts from the Weather Research and Forecasting (WRF) Model in a cycled system. Results are presented of the impact of treating water vapor as a lognormal random variable. Included in the analysis are: 1) the evolution of Tropical Storm Chris from 2006, and 2) an analysis of a "Pineapple Express" water vapor event from 2005 where a lognormal signal has been previously detected.

  19. Status of high current ion source operation at the GSI accelerator facility.

    PubMed

    Hollinger, R; Galonska, M; Gutermuth, B; Heymach, F; Krichbaum, H; Leible, K-D; Ochs, K; Schäffer, P; Schäffer, S; Spädtke, P; Stork, M; Wesp, A; Mayr, R

    2008-02-01

    Vacuum arc ion sources, Penning ion sources, and filament driven multicusp ion sources are used for the production of high current ion beams of a variety of metallic and gaseous ions at the GSI accelerator facility. For accelerator operation, the ion sources have to provide a stable beam over a long period of time with an energy of 2.2 keV/u and a maximum mass over charge ratio of 65. The status of beam time operation at the high current injector is presented here giving an outline on important ion source data, such as ion beam current, ion beam spectrum, transversal emittance, life time, duty factor, and transmission along the low energy beam transport section.

  20. Status of high current ion source operation at the GSI accelerator facility

    SciTech Connect

    Hollinger, R.; Galonska, M.; Gutermuth, B.; Heymach, F.; Krichbaum, H.; Leible, K.-D.; Ochs, K.; Schaeffer, P.; Schaeffer, S.; Spaedtke, P.; Stork, M.; Wesp, A.; Mayr, R.

    2008-02-15

    Vacuum arc ion sources, Penning ion sources, and filament driven multicusp ion sources are used for the production of high current ion beams of a variety of metallic and gaseous ions at the GSI accelerator facility. For accelerator operation, the ion sources have to provide a stable beam over a long period of time with an energy of 2.2 keV/u and a maximum mass over charge ratio of 65. The status of beam time operation at the high current injector is presented here giving an outline on important ion source data, such as ion beam current, ion beam spectrum, transversal emittance, life time, duty factor, and transmission along the low energy beam transport section.

  1. Experimental Evidence of the 90° Stop Band in the GSI UNILAC

    NASA Astrophysics Data System (ADS)

    Groening, L.; Barth, W.; Bayer, W.; Clemente, G.; Dahl, L.; Forck, P.; Gerhard, P.; Hofmann, I.; Kaiser, M. S.; Maier, M.; Mickat, S.; Milosic, T.; Jeon, D.; Uriot, D.

    2009-06-01

    In a particle accelerator with a periodic structure beam space charge force may excite resonant beam emittance growth if the particle’s transverse phase advance approaches 90°. A recent simulation study with the PARMILA code [D. Jeon , Phys. Rev. ST Accel. BeamsPRABFM1098-4402 12, 054204 (2009)]10.1103/PhysRevSTAB.12.054204 has shown the feasibility of measuring the stop band of this fourth order resonance in the GSI Universal Linear Accelerator UNILAC and proposed its experimental verification, which is reported here. Measurements of transverse phase space distributions behind a periodically focusing structure reveal a fourfold symmetry characteristic of fourth order resonances as well as a resonance stop band above σ0=90° per focusing cell. These experimental findings agree with results from three different beam dynamics simulation codes, i.e., DYNAMION, PARMILA, and TRACEWIN.

  2. The GSI 36 MHz high-current IH-type RFQ and HIIF-relevant extensions

    NASA Astrophysics Data System (ADS)

    Ratzinger, U.; Kaspar, K.; Malwitz, E.; Minaev, S.; Tiede, R.

    The GSI High-Current Injector linac for ions with mass to charge ratios up to 65 and beam intensities up to 16 mA is under construction and will deliver beam in 1999. The first section of that linac is a 36 MHz RFQ cavity with a total length of 9.2 m and an energy range from 2.2 to 120 keV/u. It will be the first RFQ in H110-mode operation. The advantages of that RF structure for the acceleration of very heavy ion beams are outlined. MAFIA calculations are compared with the results from bead pull measurements of the completed cavity. Possible extensions of that type of RF structure towards a multibeam cavity are discussed.

  3. The ASY-EOS experiment at GSI: investigating symmetry energy at supra-saturation densities

    NASA Astrophysics Data System (ADS)

    Russotto, P.; Chartier, M.; Cozma, M. D.; De Filippo, E.; Le Fèvre, A.; Gannon, S.; Gašparić, I.; Kiš, M.; Kupny, S.; Leifels, Y.; Lemmon, R. C.; Li, Q.; Łukasik, J.; Marini, P.; Pawłowski, P.; Santoro, S.; Trautmann, W.; Veselsky, M.; Acosta, L.; Adamczyk, M.; Al-Ajlan, A.; Al-Garawi, M.; Al-Homaidhi, S.; Amorini, F.; Auditore, L.; Aumann, T.; Ayyad, Y.; Baran, V.; Basrak, Z.; Bassini, R.; Benlliure, J.; Boiano, C.; Boisjoli, M.; Boretzky, K.; Brzychczyk, J.; Budzanowski, A.; Cardella, G.; Cammarata, P.; Chajecki, Z.; Chbihi, A.; Colonna, M.; Czech, B.; Di Toro, M.; Famiano, M.; Greco, V.; Grassi, L.; Guazzoni, C.; Guazzoni, P.; Heil, M.; Heilborn, L.; Introzzi, R.; Isobe, T.; Kezzar, K.; Krasznahorkay, A.; Kurz, N.; La Guidara, E.; Lanzalone, G.; Lasko, P.; Lombardo, I.; Lynch, W. G.; Matthews, Z.; May, L.; Minniti, T.; Mostazo, M.; Pagano, A.; Papa, M.; Pirrone, S.; Pleskac, R.; Politi, G.; Porto, F.; Reifarth, R.; Reisdorf, W.; Riccio, F.; Rizzo, F.; Rosato, E.; Rossi, D.; Simon, H.; Skwirczynska, I.; Sosin, Z.; Stuhl, L.; Trifirò, A.; Trimarchi, M.; Tsang, M. B.; Verde, G.; Vigilante, M.; Wieloch, A.; Wigg, P.; Wolter, H. H.; Wu, P.; Yennello, S.; Zambon, P.; Zetta, L.; Zoric, M.

    2014-03-01

    The elliptic-flow ratio of neutrons with respect to protons or light complex particles in reactions of heavy-ions at pre-relativistic energies has been proposed as an observable sensitive to the strength of the symmetry term of the nuclear equation of state at supra-saturation densities. The results obtained from the existing FOPI/LAND data for 197Au+197Au collisions at 400 MeV/nucleon in comparison with the UrQMD model simulations favoured a moderately soft symmetry term, but suffer from a considerable statistical uncertainty. These results have been confirmed by an independent analysis based on the Tübingen QMD simulations. In order to obtain an improved data set for Au+Au collisions and to extend the study to other systems, a new experiment was carried out at the GSI laboratory by the ASY-EOS collaboration. The present status of the data analysis is reported

  4. Measurement of the coupling impedances of the kickers in the SIS and ESR at GSI.

    NASA Astrophysics Data System (ADS)

    Blell, U.

    1997-05-01

    At high particle intensities coherent transverse beam oscillations may be excited due to the coupling of the beam to individual accelerators structures. The characteristic values to describe these beam instabilities are the longitudinal- and transverse coupling impedances. One reason for this beam instability is the inductive interaction between the beam and the kicker magnets. The type of the magnet, e.g. window-frame magnet or C-magnet, and its external electrical network are the most important quantities to identify the coupling impedances below the cut-off frequency of the beam pipe. For the kicker modules in the SIS and ESR accelerators at GSI the mathematical basis, theory and measured results will be presented.

  5. Status of high current ion source operation at the GSI accelerator facilitya)

    NASA Astrophysics Data System (ADS)

    Hollinger, R.; Galonska, M.; Gutermuth, B.; Heymach, F.; Krichbaum, H.; Leible, K.-D.; Ochs, K.; Schäffer, P.; Schäffer, S.; Spädtke, P.; Stork, M.; Wesp, A.; Mayr, R.

    2008-02-01

    Vacuum arc ion sources, Penning ion sources, and filament driven multicusp ion sources are used for the production of high current ion beams of a variety of metallic and gaseous ions at the GSI accelerator facility. For accelerator operation, the ion sources have to provide a stable beam over a long period of time with an energy of 2.2keV/u and a maximum mass over charge ratio of 65. The status of beam time operation at the high current injector is presented here giving an outline on important ion source data, such as ion beam current, ion beam spectrum, transversal emittance, life time, duty factor, and transmission along the low energy beam transport section.

  6. Is the GSI anomaly due to neutrino oscillations? A real time perspective

    SciTech Connect

    Wu Jun; Boyanovsky, Daniel; Hutasoit, Jimmy A.; Holman, Richard

    2010-08-15

    We study a model for the 'GSI anomaly' in which we obtain the time evolution of the population of parent and daughter particles directly in real time, considering explicitly the quantum entanglement between the daughter particle and neutrino mass eigenstates in the two-body decay. We confirm that the decay rate of the parent particle and the growth rate of the daughter particle do not feature a time modulation from interference of neutrino mass eigenstates. The lack of interference is a consequence of the orthogonality of the mass eigenstates. This result also follows from the density matrix obtained by tracing out the unobserved neutrino states. We confirm this result by providing a complementary explanation based on Cutkosky rules applied to the Feynman diagram that describes the self energy of the parent particle.

  7. A pulsed supersonic gas jet target for precision spectroscopy at the HITRAP facility at GSI

    NASA Astrophysics Data System (ADS)

    Tiedemann, D.; Stiebing, K. E.; Winters, D. F. A.; Quint, W.; Varentsov, V.; Warczak, A.; Malarz, A.; Stöhlker, Th.

    2014-11-01

    A pulsed supersonic gas jet target for experiments at the HITRAP facility at the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt has been designed and built as a multi-purpose installation for key experiments on fundamental atomic physics in strong fields. This setup is currently installed at the Institut für Kernphysik of Goethe-University, Frankfurt am Main (IKF), in order to explore its operation prior to its installation at the HITRAP facility. Design and performance of the target are described. The measured target densities of 5.9×1012 atoms/cm3 for helium and 8.1×1012 atoms/cm³ for argon at the stagnation pressure of 30 bar match the required values. The target-beam diameter of 0.9 mm and the pulsed operation mode (jet built-up-time ≤15 ms) are well suited for the use at HITRAP.

  8. Metallic magnetic calorimeters for high precision QED tests at GSI/FAIR

    NASA Astrophysics Data System (ADS)

    Pies, C.; Pabinger, A.; Kempf, S.; Fleischmann, A.; Gastaldo, L.; Enss, C.

    2009-12-01

    The quantum electrodynamics belongs to the best tested and established theories in modern physics. However, the evaluation of high order processes, as necessary in the presence of large electric fields, is still demanding. Of particular interest in this field is the Lamb shift of highly charged, hydrogen-like ions, as the theoretically claimed error bars start to be smaller than the experimental ones. We recently started to develop a 1×8 detector array for high resolution x-ray spectroscopy of hydrogen-like Uranium at the GSI/FAIR. The detectors are designed to have an energy resolution below 30 eV in the relevant energy range up to 100 keV. We discuss the considerations that lead to our present detector design, as well as the present micro-fabrication techniques.

  9. The KONUS IH-DTL proposal for the GSI UNILAC poststripper linac replacement

    NASA Astrophysics Data System (ADS)

    Hähnel, H.; Ratzinger, U.; Tiede, R.

    2017-07-01

    Motivated by the necessary replacement of the GSI UNILAC poststripper linac, a compact and efficient linac design based on IH-type cavities has been developed. Using KONUS beam dynamics, it was possible to design a linac consisting of only five cavities that can be operated by the existing UNILAC RF amplifier structure. The transversal focusing scheme is based on magnetic quadrupole triplet lenses. The optimized design provides full transmission and low emittance growth for the design current of 15 emA U28+, accelerating the beam from 1.4 MeV/u to 11.4 MeV/u. Extensive error studies were performed to define tolerances and verify the stability of the design with respect to misalignment and injection parameters. The design provides a compact and cost effective alternative to a new Alvarez linac. With a total length of just 22.8 meters it will leave room for future energy upgrades in the UNILAC tunnel.

  10. Facility for Antiproton and Ion Research, FAIR, at the GSI site

    NASA Astrophysics Data System (ADS)

    Rosner, Guenther

    2006-11-01

    FAIR is a new large-scale particle accelerator facility to be built at the GSI site in Germany. The research pursued at FAIR will cover a wide range of topics in nuclear and hadron physics, as well as high density plasma physics, atomic and antimatter physics, and applications in condensed matter physics and biology. The working horse of FAIR will be a 1.1km circumference double ring of rapidly cycling 100 and 300Tm synchrotrons, which will be used to produce high intensity secondary beams of short-lived radioactive ions or antiprotons. A subsequent suite of cooler and storage rings will deliver heavy ion and antiproton beams of unprecedented quality. Large experimental facilities are presently being designed by the NUSTAR, PANDA, PAX, CBM, SPARC, FLAIR, HEDgeHOB and BIOMAT collaborations.

  11. Transversity Measurement with Polarized Proton and Antiproton Interactions at Gsi:. the Pax Experiment

    NASA Astrophysics Data System (ADS)

    Dalpiaz, P. F.

    2006-02-01

    It has recently been suggested by the PAX collaboration that collisions of transversely polarized protons and antiprotons at the GSI-FAIR can be used to determine the nucleon's transversity densities from measurements of the double-spin asymmetry for the Drell-Yan process. The theoretical expectations for this observable are in the 0.3-0.4 range at the FAIR-HESR enrgies. PAX therefore proposes to build a polarized antiproton stored beam suitable for this measurament. Polarized antiprotons will be produced by spin filtering with an internal polarized gas target in a storage ring. The design and performance of the accelerator setup, and of the the detector will be briefly outlined.

  12. Experiments on the interaction of heavy ions with dense plasma at GSI-Darmstadt

    NASA Astrophysics Data System (ADS)

    Stöckl, C.; Boine-Frankenheim, O.; Geißel, M.; Roth, M.; Wetzler, H.; Seelig, W.; Iwase, O.; Spiller, P.; Bock, R.; Süß, W.; Hoffmann, D. H. H.

    One of the main objectives of the experimental plasma physics activities at the Gesellschaft für Schwerionenforschung (GSI) are the interaction processes of heavy ions with dense ionized matter. Gas-discharge plasma targets were used for energy loss and charge state measurements in a regime of electron density and temperature up to 10 19 cm -3 and 20 eV, respectively. An improved model of the charge exchange processes in fully ionized hydrogen plasma, taking into account multiple excited electronic configurations which subsequently ionize, has removed the discrepancies of previous theoretical descriptions. The energy loss of the ion beam in partially ionized plasmas such as argon was found to agree very well with our simple theoretical model based on the modified Bethe-Bloch theory. A new setup with a 100 J/5 GW Nd-glass laser now provides access to density ranges up to 10 21 cm -3 and temperatures of up to 100 eV. First results of interaction experiments with laser-produced plasma are presented. To fully exploit the experimental possibilities of the new laser-plasma setup both improved charge state detection systems and better plasma diagnostics are indispensable. Present developments and future possibilities in these fields are presented. This paper summarizes the following contributions: Interaction of heavy-ion beams with laser plasma by C. Stöckl et al. Energy Loss of Heavy Ions in a laser-produced plasma by M. Roth et al. Charge state measurements of heavy ions passing a laser produced plasma with high time resolution by W. Süß et al. Plasma diagnostics for laser-produced plasma by O. Iwase et al. Future possibilities of plasma diagnostics at GSI by M. Geißel et al.

  13. Studies on exotic nuclei by proton-induced direct reaction at GSI and FAIR

    SciTech Connect

    Kiselev, O. A.

    2007-02-26

    The proton-induced direct reactions like elastic, quasi-elastic scattering and knock-out at intermediate energies and inverse kinematics are the most powerful classical methods for obtaining spectroscopic information on the structure of unstable exotic nuclei. Few elastic scattering experiments performed at GSI with the gaseous and liquid hydrogen targets provided the most precise data on a nuclear matter distribution and a halo-core structure of the neutron-rich He and Li isotopes. The measured differential cross sections have been also used for probing density distributions as predicted by various microscopic theories. The comparison of the data with the latest calculations will be shown. The description of the recent experiment with proton-rich 8B and neutron-rich Be isotopes is presented.The experimental conditions at the future facility FAIR will provide unique opportunities for nuclear structure studies on nuclei far off stability, and will allow to reach new regions in the chart of nuclides of high interest for nuclear structure and astrophysics. In particular, predicted luminosity will allow for the investigation of direct reactions with stored and cooled radioactive beams at internal H, He, etc. targets of the storage ring NESR. This technique enables high resolution measurements down to very low momentum transfer and provides a gain in luminosity from accumulation and recirculation of the radioactive beams. In order to explore the experimental conditions for measurements planned at EXL/FAIR setup, a first attempt exploring experimentally the feasibility of its concept has been recently made. A detector setup was installed at the ESR storage ring at GSI, Darmstadt. A 136Xe beam was interacting to an internal hydrogen gas-jet target. The detector setup had all the basic ingredients as foreseen by EXL collaboration. A set of scattering reactions has been studied and the overall performance of the setup demonstrated the feasibility of the EXL experimental

  14. Discovery of biomarkers predictive of GSI response in triple-negative breast cancer and adenoid cystic carcinoma.

    PubMed

    Stoeck, Alexander; Lejnine, Serguei; Truong, Andrew; Pan, Li; Wang, Hongfang; Zang, Chongzhi; Yuan, Jing; Ware, Chris; MacLean, John; Garrett-Engele, Philip W; Kluk, Michael; Laskey, Jason; Haines, Brian B; Moskaluk, Christopher; Zawel, Leigh; Fawell, Stephen; Gilliland, Gary; Zhang, Theresa; Kremer, Brandon E; Knoechel, Birgit; Bernstein, Bradley E; Pear, Warren S; Liu, X Shirley; Aster, Jon C; Sathyanarayanan, Sriram

    2014-10-01

    Next-generation sequencing was used to identify Notch mutations in a large collection of diverse solid tumors. NOTCH1 and NOTCH2 rearrangements leading to constitutive receptor activation were confined to triple-negative breast cancers (TNBC; 6 of 66 tumors). TNBC cell lines with NOTCH1 rearrangements associated with high levels of activated NOTCH1 (N1-ICD) were sensitive to the gamma-secretase inhibitor (GSI) MRK-003, both alone and in combination with paclitaxel, in vitro and in vivo, whereas cell lines with NOTCH2 rearrangements were resistant to GSI. Immunohistochemical staining of N1-ICD in TNBC xenografts correlated with responsiveness, and expression levels of the direct Notch target gene HES4 correlated with outcome in patients with TNBC. Activating NOTCH1 point mutations were also identified in other solid tumors, including adenoid cystic carcinoma (ACC). Notably, ACC primary tumor xenografts with activating NOTCH1 mutations and high N1-ICD levels were sensitive to GSI, whereas N1-ICD-low tumors without NOTCH1 mutations were resistant. NOTCH1 mutations, immunohistochemical staining for activated NOTCH1, and HES4 expression are biomarkers that can be used to identify solid tumors that are likely to respond to GSI-based therapies. ©2014 American Association for Cancer Research.

  15. MEASURED AND CALCULATED LOSSES IN A MODEL DIPOLE FOR GSI'S HEAVY ION SYNCHROTRON.

    SciTech Connect

    WANDERER,P.; ANERELLA,M.; GANETIS,G.; GHOSH,A.K.; JOSHI,P.; MARONE,A.; MURATORE,J.; ET AL.

    2003-06-15

    The new heavy ion synchrotron facility proposed by GSI will have two superconducting magnet rings in the same tunnel, with rigidities of 300T{center_dot}m and 10OT{center_dot}m. Fast ramp times are needed. These can cause problems of ac loss and field distortion in the magnets. For the high energy ring, a lm model dipole magnet has been built, based on the RHIC dipole design. This magnet was tested under boiling liquid helium in a vertical dewar. The quench current showed very little dependence on ramp rate. The ac losses, measured by an electrical method, were fitted to straight line plots of loss/cycle versus ramp rate, thereby separating the eddy current and hysteresis components. These results were compared with calculated values, using parameters which had previously been measured on short samples of cable. Reasonably good agreement between theory and experiment was found, although the measured hysteresis loss is higher than expected in ramps to the highest field levels.

  16. Results of the ASY-EOS experiment at GSI: The symmetry energy at suprasaturation density

    NASA Astrophysics Data System (ADS)

    Russotto, P.; Gannon, S.; Kupny, S.; Lasko, P.; Acosta, L.; Adamczyk, M.; Al-Ajlan, A.; Al-Garawi, M.; Al-Homaidhi, S.; Amorini, F.; Auditore, L.; Aumann, T.; Ayyad, Y.; Basrak, Z.; Benlliure, J.; Boisjoli, M.; Boretzky, K.; Brzychczyk, J.; Budzanowski, A.; Caesar, C.; Cardella, G.; Cammarata, P.; Chajecki, Z.; Chartier, M.; Chbihi, A.; Colonna, M.; Cozma, M. D.; Czech, B.; De Filippo, E.; Di Toro, M.; Famiano, M.; Gašparić, I.; Grassi, L.; Guazzoni, C.; Guazzoni, P.; Heil, M.; Heilborn, L.; Introzzi, R.; Isobe, T.; Kezzar, K.; Kiš, M.; Krasznahorkay, A.; Kurz, N.; La Guidara, E.; Lanzalone, G.; Le Fèvre, A.; Leifels, Y.; Lemmon, R. C.; Li, Q. F.; Lombardo, I.; Łukasik, J.; Lynch, W. G.; Marini, P.; Matthews, Z.; May, L.; Minniti, T.; Mostazo, M.; Pagano, A.; Pagano, E. V.; Papa, M.; Pawłowski, P.; Pirrone, S.; Politi, G.; Porto, F.; Reviol, W.; Riccio, F.; Rizzo, F.; Rosato, E.; Rossi, D.; Santoro, S.; Sarantites, D. G.; Simon, H.; Skwirczynska, I.; Sosin, Z.; Stuhl, L.; Trautmann, W.; Trifirò, A.; Trimarchi, M.; Tsang, M. B.; Verde, G.; Veselsky, M.; Vigilante, M.; Wang, Yongjia; Wieloch, A.; Wigg, P.; Winkelbauer, J.; Wolter, H. H.; Wu, P.; Yennello, S.; Zambon, P.; Zetta, L.; Zoric, M.

    2016-09-01

    Directed and elliptic flows of neutrons and light-charged particles were measured for the reaction 197Au+197Au at 400 MeV/nucleon incident energy within the ASY-EOS experimental campaign at the GSI laboratory. The detection system consisted of the Large Area Neutron Detector (LAND), combined with parts of the CHIMERA multidetector, the ALADIN Time-of-flight Wall, and the Washington University Microball detector. The latter three arrays were used for the event characterization and reaction-plane reconstruction. In addition, an array of triple telescopes, KRATTA was used for complementary measurements of the isotopic composition and flows of light-charged particles. From the comparison of the elliptic-flow ratio of neutrons with respect to charged particles with UrQMD predictions, a value γ =0.72 ±0.19 is obtained for the power-law coefficient describing the density dependence of the potential part in the parametrization of the symmetry energy. It represents a new and more stringent constraint for the regime of suprasaturation density and confirms, with a considerably smaller uncertainty, the moderately soft to linear density dependence deduced from the earlier FOPI-LAND data. The densities probed are shown to reach beyond twice saturation.

  17. Status report on ECR ion source operation at the GSI accelerator facilities

    NASA Astrophysics Data System (ADS)

    Tinschert, K.; Bossler, J.; Schennach, S.; Schulte, H.

    1998-02-01

    The Caprice electron cyclotron resonance (ECR) ion source of the high charge state injector (HLI) as standard injection line for the UNILAC at GSI is now in permanent operation during all beam time periods of a year. So the ECR test stand which is equipped with the same version of Caprice mainly has to be used for preparatory work. Ion beams of a great variety of elements are demanded covering beam time periods of up to six weeks. Besides the stable and reliable operation with diverse gases the application of our high-temperature oven has become a standard method for all solid materials attaining a vapor pressure of 10-3 mbar between 800 and 1500 °C. It has been operated not only with pure metal samples but also with especially produced isotopic zinc oxide samples providing a stable beam of 68Zn10+ ions. Alternatively a low-temperature evaporator was constructed for high vapor pressure materials and was used for the production of Se and Zn ions. Experiences gained with the oven and evaporator method will be reported and results will be summarized. In order to investigate and improve ion extraction and beam transport through the low energy beam line under conditions equivalent to the HLI a new ECR injector setup is being built which is equipped with an identical analyzing system. The basic concept of the new setup is described.

  18. The Darmstadt Antiproton Project (PANDA) at the High Energy Storage Ring at GSI

    SciTech Connect

    Peters, Klaus J.

    2002-11-20

    Recently GSI presented the plans for a major new international research facility. A key feature of this new facility will be the delivery of intense, high-quality secondary beams which embody the production of antiprotons. For the antiproton beams a 50 Tm storage ring is planned, including electron and stochastic cooling, will be able to handle antiproton beams in the momentum range from 1.5 up to 15 GeV/c. The design luminosity is 2 x 10{sup 32} cm{sup -2} s{sup -1}. The PANDA Experiment will take place at an internal target and will cover the aspects of the structure of hadrons and the properties of hadronic matter in the corresponding energy range. The main topics to be addressed are: Spectroscopy of charmonium; Search for charmed hybrids and glueballs; Interaction of open and hidden charm with nucleons and nuclei; Single and double hypernuclei; Open charm spectroscopy; CP-Violation in the charm sector; Deeply Virtual Comptom Scattering, etc. The major part of the experimental program will make use of a general purpose detector PANDA. The concept of this detector is presented.

  19. Electrophysiological effects of 12C on patients undergoing heavy ions therapy at GSI: a pilot study

    NASA Astrophysics Data System (ADS)

    Sannita, W. G.; Narici, L.; Debus, J.; Carozzo, S.; Saturno, M.; Schardt, D.; Schulz-Ertner, D.

    Phosphenes light flashes observed in space have been attributed to heavy ions interfering with the retina photoreceptors However their generating mechanisms are still undefined and neurons of the retina and non-ocular visual structures are as sensitive to ionizing agents as retinal photoreceptors Multiple sources are therefore possible that could question safety in manned space travel Patients undergoing 12C ion therapy of skull tumors also involving the anterior optic pathway often report phosphenes similar to those described by astronauts and volunteers in accelerator experiments In a pilot study their occurrence either within each beam pulse or shortly after it in case of very short pulses correlated with the beam position and local dose deposited near the optic nerve or eye during irradiation Further research is in progress at the GSI Biophysics facilities in Darmstadt FRG Purposes of the study are 1- to identify electrophysiological cortical concomitants of phosphenes 2- to correlate phosphenes with irradiated portions of the anterior visual pathways and with known basic mechanisms of vision and 3- to obtain information to be used in the understanding of phosphenes observed in space We will present preliminary results from the first measurements

  20. Production and Decay of Element 114 Isotopes with the BGS (LBNL) and TASCA (GSI)

    NASA Astrophysics Data System (ADS)

    Gates, Jacklyn

    2010-11-01

    During the last 10 years, the Dubna Gas Filled Recoil Separator (DGFRS) group has published numerous reports of the production and decay of superheavy elements (SHE) with Z=112-118 in ^48Ca irradiations of actinide targets. Recently the production of element 114 in the ^242Pu(^48Ca,3-4n) reaction was verified at the Lawrence Berkeley National Laboratory using the Berkeley Gas-filled Separator (BGS). Later experiments at the BGS successfully extended the region of known SHE nuclides along the neutron-deficient side using the ^242Pu(^48Ca,5n)^285114 reaction. Almost concurrently with the BGS, the TransActinide Separator and Chemistry Apparatus at the GSI Helmholtzzentrum fúr Schwerionenforschung investigated the ^244Pu(^48Ca,3-4n) reaction and observed cross sections on the order of 10 pb for the production of element 114 when the more neutron-rich ^244Pu target was used. An alpha-decay branch in ^281Ds was also discovered, leading to the new nucleus ^277Hs. Cross sections, decay modes and decay properties all agree with those published by the DGFRS group. Implications of these results on the field of heavy elements will be discussed.

  1. Generic Safety Issue (GSI) 171 -- Engineered Safety Feature (ESF) failure from a loop subsequent to LOCA: Assessment of plant vulnerability and CDF contributions

    SciTech Connect

    Martinez-Guridi, G.; Samanta, P.; Chu, L.; Yang, J.

    1998-03-01

    Generic Safety Issue 171 (GSI-171), Engineered Safety Feature (ESF) from a Loss Of Offsite Power (LOOP) subsequent to a Loss Of Coolant Accident (LOCA), deals with an accident sequence in which a LOCA is followed by a LOOP. This issue was later broadened to include a LOOP followed by a LOCA. Plants are designed to handle a simultaneous LOCA and LOOP. In this paper, the authors address the unique issues that are involved i LOCA with delayed LOOP (LOCA/LOOP) and LOOP with delayed LOCA (LOOP/LOCA) accident sequences. LOCA/LOOP accidents are analyzed further by developing event-tree/fault-tree models to quantify their contributions to core-damage frequency (CDF) in a pressurized water reactor and a boiling water reactor (PWR and a BWR). Engineering evaluation and judgments are used during quantification to estimate the unique conditions that arise in a LOCA/LOOP accident. The results show that the CDF contribution of such an accident can be a dominant contributor to plant risk, although BWRs are less vulnerable than PWRs.

  2. Joint damage in rheumatoid arthritis progresses in remission according to the Disease Activity Score in 28 joints and is driven by residual swollen joints.

    PubMed

    Aletaha, Daniel; Smolen, Josef S

    2011-12-01

    Remission has been defined as the ultimate target for patients with rheumatoid arthritis. The Disease Activity Score in 28 joints (DAS28) has been criticized for the amount of disease activity that remains in patients despite their achieving DAS28 remission. This study was undertaken to investigate the significance of residual inflammation in remission in relation to radiographic progression. We pooled 1-year clinical data, kindly provided by the respective sponsors, on 864 patients in methotrexate monotherapy arms of recent pivotal trials. We identified patients who had attained persistent DAS28 remission from month 6 through month 12 (a DAS28(6-12) of <2.6). Among these patients we then assessed radiographic progression in total Sharp/van der Heijde scores (SHS) from baseline to 12 months between those with residual joint swelling (defined as a swollen joint count from month 6 through month 12 [SJC(6-12) ] of ≥2) and those without residual joint swelling (defined as an SJC(6-12) of <2). One hundred fourteen patients (13.2%) achieved a DAS28(6-12) of <2.6, of whom those without residual joint swelling (n = 92, 80.7%) had less radiographic progression over 1 year than those with residual joint swelling (n = 22, 19.3%) (mean ± SD SHS progression 0.2 ± 2.6 versus 2.2 ± 4.2; P = 0.11). Likewise, the proportion of patients with a total SHS progression of >0.5/year was significantly lower among those without joint swelling than among those with joint swelling (27.2% versus 50.0%; P = 0.039). DAS28 remitters without joint swelling showed progression comparable to that in the total group of remitters by the Simplified Disease Activity Index (remission defined as ≤3.3) and Clinical Disease Activity Index (remission defined as ≤2.8), namely, 0.2 versus -0.07 versus 0.16, respectively (P = 0.66). Radiographic progression with nonbiologic treatment is minimal only when patients in DAS28 remission have no persistent residual joint swelling. Under these conditions

  3. Monte Carlo simulations for the shielding of the future high-intensity accelerator facility FAIR at GSI.

    PubMed

    Radon, T; Gutermuth, F; Fehrenbacher, G

    2005-01-01

    The Gesellschaft für Schwerionenforschung (GSI) is planning a significant expansion of its accelerator facilities. Compared to the present GSI facility, a factor of 100 in primary beam intensities and up to a factor of 10,000 in secondary radioactive beam intensities are key technical goals of the proposal. The second branch of the so-called Facility for Antiproton and Ion Research (FAIR) is the production of antiprotons and their storage in rings and traps. The facility will provide beam energies a factor of approximately 15 higher than presently available at the GSI for all ions, from protons to uranium. The shielding design of the synchrotron SIS 100/300 is shown exemplarily by using Monte Carlo calculations with the FLUKA code. The experimental area serving the investigation of compressed baryonic matter is analysed in the same way. In addition, a dose comparison is made for an experimental area operated with medium energy heavy-ion beams. Here, Monte Carlo calculations are performed by using either heavy-ion primary particles or proton beams with intensities scaled by the mass number of the corresponding heavy-ion beam.

  4. Current Status of the Development of a Transportable and Compact VLBI System by NICT and GSI

    NASA Technical Reports Server (NTRS)

    Ishii, Atsutoshi; Ichikawa, Ryuichi; Takiguchi, Hiroshi; Takefuji, Kazuhiro; Ujihara, Hideki; Koyama, Yasuhiro; Kondo, Tetsuro; Kurihara, Shinobu; Miura, Yuji; Matsuzaka, Shigeru; Tanimoto, Daisuke

    2010-01-01

    MARBLE (Multiple Antenna Radio-interferometer for Baseline Length Evaluation) is under development by NICT and GSI. The main part of MARBLE is a transportable VLBI system with a compact antenna. The aim of this system is to provide precise baseline length over about 10 km for calibrating baselines. The calibration baselines are used to check and validate surveying instruments such as GPS receiver and EDM (Electro-optical Distance Meter). It is necessary to examine the calibration baselines regularly to keep the quality of the validation. The VLBI technique can examine and evaluate the calibration baselines. On the other hand, the following roles are expected of a compact VLBI antenna in the VLBI2010 project. In order to achieve the challenging measurement precision of VLBI2010, it is well known that it is necessary to deal with the problem of thermal and gravitational deformation of the antenna. One promising approach may be connected-element interferometry between a compact antenna and a VLBI2010 antenna. By measuring repeatedly the baseline between the small stable antenna and the VLBI2010 antenna, the deformation of the primary antenna can be measured and the thermal and gravitational models of the primary antenna will be able to be constructed. We made two prototypes of a transportable and compact VLBI system from 2007 to 2009. We performed VLBI experiments using theses prototypes and got a baseline length between the two prototypes. The formal error of the measured baseline length was 2.7 mm. We expect that the baseline length error will be reduced by using a high-speed A/D sampler.

  5. NASA SPoRT Modeling and Data Assimilation Research and Transition Activities Using WRF, LIS and GSI

    NASA Technical Reports Server (NTRS)

    Case, Jonathan L.; Blankenship, Clay B.; Zavodsky, Bradley T.; Srikishen, Jayanthi; Berndt, Emily B.

    2014-01-01

    weather research and forecasting ===== The NASA Short-term Prediction Research and Transition (SPoRT) program has numerous modeling and data assimilation (DA) activities in which the WRF model is a key component. SPoRT generates realtime, research satellite products from the MODIS and VIIRS instruments, making the data available to NOAA/NWS partners running the WRF/EMS, including: (1) 2-km northwestern-hemispheric SST composite, (2) daily, MODIS green vegetation fraction (GVF) over CONUS, and (3) NASA Land Information System (LIS) runs of the Noah LSM over the southeastern CONUS. Each of these datasets have been utilized by specific SPoRT partners in local EMS model runs, with select offices evaluating the impacts using a set of automated scripts developed by SPoRT that manage data acquisition and run the NCAR Model Evaluation Tools verification package. SPoRT is engaged in DA research with the Gridpoint Statistical Interpolation (GSI) and Ensemble Kalman Filter in LIS for soil moisture DA. Ongoing DA projects using GSI include comparing the impacts of assimilating Atmospheric Infrared Sounder (AIRS) radiances versus retrieved profiles, and an analysis of extra-tropical cyclones with intense non-convective winds. As part of its Early Adopter activities for the NASA Soil Moisture Active Passive (SMAP) mission, SPoRT is conducting bias correction and soil moisture DA within LIS to improve simulations using the NASA Unified-WRF (NU-WRF) for both the European Space Agency's Soil Moisture Ocean Salinity and upcoming SMAP mission data. SPoRT has also incorporated real-time global GVF data into LIS and WRF from the VIIRS product being developed by NOAA/NESDIS. This poster will highlight the research and transition activities SPoRT conducts using WRF, NU-WRF, EMS, LIS, and GSI.

  6. Hypochlorite-induced damage to proteins: formation of nitrogen-centred radicals from lysine residues and their role in protein fragmentation.

    PubMed Central

    Hawkins, C L; Davies, M J

    1998-01-01

    Stimulated monocytes and neutrophils generate hypochlorite (HOCl) via the release of the enzyme myeloperoxidase and hydrogen peroxide. HOCl damages proteins by reaction with amino acid side-chains or backbone cleavage. Little information is available about the mechanisms and intermediates involved in these reactions. EPR spin trapping has been employed to identify radicals on proteins, peptides and amino acids after treatment with HOCl. Reaction with HOCl gives both high- and low-molecular-mass nitrogen-centred, protein-derived radicals; the yield of the latter increases with both higher HOCl:protein ratios and enzymic digestion. These radicals, which arise from lysine side-chain amino groups, react with ascorbate, glutathione and Trolox. Reaction of HOCl-treated proteins with excess methionine eliminates radical formation, which is consistent with lysine-derived chloramines (via homolysis of N-Cl bonds) being the radical source. Incubation of HOCl-treated proteins, after removal of excess oxidant, gives rise to both nitrogen-centred radicals, over a period of hours, and time-dependent fragmentation of the protein. Treatment with excess methionine or antioxidants (Trolox, ascorbate, glutathione) protects against fragmentation; urate and bilirubin do not. Chloramine formation and nitrogen-centred radicals are therefore key species in HOCl-induced protein fragmentation. PMID:9620862

  7. Gsy, a novel glucansucrase from Leuconostoc mesenteroides, mediates the formation of cell aggregates in response to oxidative stress

    PubMed Central

    Yan, Minghui; Han, Jin; Xu, Xiaofen; Liu, Lianliang; Gao, Caixia; Zheng, Huajun; Chen, Yunxia; Tao, Yimin; Zhou, Hu; Li, Yunfei; Wu, Zhengjun

    2016-01-01

    Leuconostoc mesenteroides is a member of lactic acid bacteria (LAB) with wide applications in the food and medical industries. Species in the genus Leuconostoc are catalase-negative and generally regarded as facultative anaerobic or aerotolerant organisms. Despite their extensive use in industry, certain issues concerning the aerobic life of L. mesenteroides, e.g., the mechanism involved in the tolerance to oxygen, remain to be addressed. In this manuscript, a survival strategy employed by L. mesenteroides BD3749 in response to oxidative stress was elucidated. BD3749 cells cultivated in medium with sucrose available synthesized large amounts of exopolysaccharides, mostly consisting of insoluble EPS. When BD3749 cells were challenged with oxidative stress, the amount of insoluble EPS was greatly enhanced. The synthesized EPSs reduced the accumulation of reactive oxygen species (ROS) in bacterial cells and improved their survival during chronic oxidative stress. Another study showed that Gsy, a novel glucansucrase in the GH70 family that is induced by sucrose and up-regulated following exposure to oxygen, was responsible for the synthesis of insoluble EPS. Gsy was subsequently demonstrated to play pivotal roles in the formation of aggregates to alleviate the detrimental effects on BD3749 cells exerted by oxygen. PMID:27924943

  8. Time Modulation of the K-Shell Electron Capture Decay Rates of H-like Heavy Ions at GSI Experiments

    SciTech Connect

    Ivanov, A. N.; Kienle, P.

    2009-08-07

    According to experimental data at GSI, the rates of the number of daughter ions, produced by the nuclear K shell electron capture decays of the H-like heavy ions with one electron in the K shell, such as {sup 140}Pr{sup 58+}, {sup 142}Pm{sup 60+}, and {sup 122}I{sup 52+}, are modulated in time with periods T{sub EC} of the order of a few seconds, obeying an A scaling T{sub EC}=A/20 s, where A is the mass number of the mother nuclei, and with amplitudes a{sub d}{sup EC}approx0.21. We show that these data can be explained in terms of the interference of two massive neutrino mass eigenstates. The appearance of the interference term is due to overlap of massive neutrino mass eigenstate energies and of the wave functions of the daughter ions in two-body decay channels, caused by the energy and momentum uncertainties introduced by time differential detection of the daughter ions in GSI experiments.

  9. Begacestat (GSI-953): a novel, selective thiophene sulfonamide inhibitor of amyloid precursor protein gamma-secretase for the treatment of Alzheimer's disease.

    PubMed

    Martone, Robert L; Zhou, Hua; Atchison, Kevin; Comery, Thomas; Xu, Jane Z; Huang, Xinyi; Gong, Xioahai; Jin, Mei; Kreft, Anthony; Harrison, Boyd; Mayer, Scott C; Aschmies, Suzan; Gonzales, Cathleen; Zaleska, Margaret M; Riddell, David R; Wagner, Erik; Lu, Peimin; Sun, Shaiu-Ching; Sonnenberg-Reines, June; Oganesian, Aram; Adkins, Karissa; Leach, Michael W; Clarke, David W; Huryn, Donna; Abou-Gharbia, Magid; Magolda, Ronald; Bard, Jonathan; Frick, Glen; Raje, Sangeeta; Forlow, S Bradley; Balliet, Carrie; Burczynski, Michael E; Reinhart, Peter H; Wan, Hong I; Pangalos, Menelas N; Jacobsen, J Steven

    2009-11-01

    The presenilin containing gamma-secretase complex is responsible for the regulated intramembraneous proteolysis of the amyloid precursor protein (APP), the Notch receptor, and a multitude of other substrates. gamma-Secretase catalyzes the final step in the generation of Abeta(40) and Abeta(42) peptides from APP. Amyloid beta-peptides (Abeta peptides) aggregate to form neurotoxic oligomers, senile plaques, and congophilic angiopathy, some of the cardinal pathologies associated with Alzheimer's disease. Although inhibition of this protease acting on APP may result in potentially therapeutic reductions of neurotoxic Abeta peptides, nonselective inhibition of the enzyme may cause severe adverse events as a result of impaired Notch receptor processing. Here, we report the preclinical pharmacological profile of GSI-953 (begacestat), a novel thiophene sulfonamide gamma-secretase inhibitor (GSI) that selectively inhibits cleavage of APP over Notch. This GSI inhibits Abeta production with low nanomolar potency in cellular and cell-free assays of gamma-secretase function, and displaces a tritiated analog of GSI-953 from enriched gamma-secretase enzyme complexes with similar potency. Cellular assays of Notch cleavage reveal that this compound is approximately 16-fold selective for the inhibition of APP cleavage. In the human APP-overexpressing Tg2576 transgenic mouse, treatment with this orally active compound results in a robust reduction in brain, plasma, and cerebral spinal fluid Abeta levels, and a reversal of contextual fear-conditioning deficits that are correlated with Abeta load. In healthy human volunteers, oral administration of a single dose of GSI-953 produces dose-dependent changes in plasma Abeta levels, confirming pharmacodynamic activity of GSI-953 in humans.

  10. Strange meson-baryon interaction in hot and dense medium: recent progress for a road to GSI/FAIR

    NASA Astrophysics Data System (ADS)

    Cabrera, D.; Tolos, L.; Aichelin, J.; Bratkovskaya, E.

    2016-01-01

    We report recent results on the dynamics of strange hadrons in two-body reactions relevant for near-threshold production in heavy-ion collisions at GSI/FAIR and NICA-Dubna. In particular, K¯N scattering in hot and dense nuclear matter is studied within a chiral unitary framework in coupled channels, setting up the starting point for implementations in microscopic off-shell transport approaches. We focus on the calculation of transition rates with special attention to the excitation of hyperon resonances and isospin effects. Additionally, we explore “unconventional” strangeness generation by meson-meson and meson-baryon interactions in connection with recent HADES observations of deep sub-threshold Φ and Ξ production.

  11. Data-flow coupling and data-acquisition triggers for the PreSPEC-AGATA campaign at GSI

    NASA Astrophysics Data System (ADS)

    Ralet, D.; Pietri, S.; Aubert, Y.; Bellato, M.; Bortolato, D.; Brambilla, S.; Camera, F.; Dosme, N.; Gadea, A.; Gerl, J.; Golubev, P.; Grave, X.; Johansson, H. T.; Karkour, N.; Korichi, A.; Kurz, N.; Lafay, X.; Legay, E.; Linget, D.; Pietralla, N.; Rudolph, D.; Schaffner, H.; Stezowski, O.; Travers, B.; Wieland, O.

    2015-06-01

    The PreSPEC setup for high-resolution γ-ray spectroscopy using radioactive ion beams was employed for experimental campaigns in 2012 and 2014. The setup consisted of the state of the art Advanced GAmma Tracking Array (AGATA) and the High Energy γ deteCTOR (HECTOR+) positioned around a secondary target at the final focal plane of the GSI FRagment Separator (FRS) to perform in-beam γ-ray spectroscopy of exotic nuclei. The Lund York Cologne CAlorimeter (LYCCA) was used to identify the reaction products. In this paper we report on the trigger scheme used during the campaigns. The data-flow coupling between the Multi-Branch System (MBS) based Data AcQuisition (DAQ) used for FRS-LYCCA and the "Nouvelle Acquisition temps Réel Version 1.2 Avec Linux" (NARVAL) based acquisition system used for AGATA are also described.

  12. A new data acquisition system for Schottky signals in atomic physics experiments at GSI's and FAIR's storage rings

    NASA Astrophysics Data System (ADS)

    Trageser, C.; Brandau, C.; Kozhuharov, C.; Litvinov, Yu A.; Müller, A.; Nolden, F.; Sanjari, S.; Stöhlker, T.

    2015-11-01

    A new continuous and broadband data acquisition system for measurements of Schottky-signals of ions revolving in a storage ring has been implemented. This set-up is capable of recording the radio frequency (RF) signal of the ions that circulate in the storage ring with a sustained acquisition rate of more than 3.5× {10}7 IQ-samples per second. This allows several harmonics of the full momentum acceptance of a storage ring to be measured at the same time. The RF signal analyzer modules are complemented by further electronic modules such as counters, precision clocks and synchronization modules that facilitate a seamless integration with main experimental data acquisitions for atomic and nuclear physics. In this contribution, the setup and first results from a test run at the experimental storage ring at GSI, Darmstadt, Germany, are presented.

  13. Gamma-Secretase Inhibitor IX (GSI) Impairs Concomitant Activation of Notch and wnt-beta-catenin Pathways in CD44(+) Gastric Cancer Stem Cells.

    PubMed

    Barat, Samarpita; Chen, Xi; Cuong Bui, Khac; Bozko, Przemyslaw; Götze, Julian; Christgen, Matthias; Krech, Till; Malek, Nisar P; Plentz, Ruben R

    2017-02-03

    Cancer stem cells (CSC) are associated with tumor resistance and are characterized in gastric cancer (GC). Studies have indicated that Notch and wnt-beta-catenin pathways are crucial for CSC development. Using CD44(+) CSCs, we investigated the role of these pathways in GC carcinogenesis. We performed cell proliferation, wound healing, invasion, tumorsphere, and apoptosis assays. Immunoblot analysis of downstream signaling targets of Notch and wnt-beta-catenin were tested after gamma-secretase inhibitor IX (GSI) treatment. Immunohistochemistry, immunofluorescence, and Fluorescence activated cell sorting (FACS) were used to determine CD44 and Hairy enhancer of split-1 (Hes1) expression in human GC tissues. CD44(+) CSCs were subcutaneously injected into NMR-nu/nu mice and treated with vehicle or GSI. GC patients with expression of CD44 and Hes1 showed overall reduced survival. CD44(+) CSCs showed high expression of Hes1. GSI treatment showed effective inhibition of cell proliferation, migration, invasion, tumor sphere formation of CD44(+) CSCs, and induced apoptosis. Importanly, Notch1 was found to be important in mediating a crosstalk between Notch and wnt-beta-catenin in CD44(+) CSCs. Our study highlights a crosstalk between Notch and wnt-beta-catenin in gastric CD44(+) CSCs. Expression of CD44 and Hes1 is associated with patient overall survival. GSI could be an alternative drug to treat GC. © Stem Cells Translational Medicine 2017.

  14. Nonuniform radiation damage in permanent magnet quadrupoles.

    PubMed

    Danly, C R; Merrill, F E; Barlow, D; Mariam, F G

    2014-08-01

    We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL's pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components.

  15. Nonuniform radiation damage in permanent magnet quadrupoles

    SciTech Connect

    Danly, C. R.; Merrill, F. E.; Barlow, D.; Mariam, F. G.

    2014-08-15

    We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL’s pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components.

  16. The capture and dissemination of integrated 3D geospatial knowledge at the British Geological Survey using GSI3D software and methodology

    NASA Astrophysics Data System (ADS)

    Kessler, Holger; Mathers, Steve; Sobisch, Hans-Georg

    2009-06-01

    The Geological Surveying and Investigation in 3 Dimensions (GSI3D) software tool and methodology has been developed over the last 15 years. Since 2001 this has been in cooperation with the British Geological Survey (BGS). To-date over a hundred BGS geologists have learned to use the software that is now routinely deployed in building systematic and commercial 3D geological models. The success of the GSI3D methodology and software is based on its intuitive design and the fact that it utilises exactly the same data and methods, albeit in digital forms, that geologists have been using for two centuries in order to make geological maps and cross-sections. The geologist constructs models based on a career of observation of geological phenomena, thereby incorporating tacit knowledge into the model. This knowledge capture is a key element to the GSI3D approach. In BGS GSI3D is part of a much wider set of systems and work processes that together make up the cyberinfrastructure of a modern geological survey. The GSI3D software is not yet designed to cope with bedrock structures in which individual stratigraphic surfaces are repeated or inverted, but the software is currently being extended by BGS to encompass these more complex geological scenarios. A further challenge for BGS is to enable its 3D geological models to become part of the semantic Web using GML application schema like GeoSciML. The biggest benefits of widely available systematic geological models will be an enhanced public understanding of the sub-surface in 3D, and the teaching of geoscience students.

  17. The anti/syn conformation of 8-oxo-7,8-dihydro-2'-deoxyguanosine is modulated by Bacillus subtilis PolX active site residues His255 and Asn263. Efficient processing of damaged 3'-ends.

    PubMed

    Zafra, Olga; Pérez de Ayala, Lucía; de Vega, Miguel

    2017-04-01

    8-oxo-7,8-dihydro-2'-deoxyguanosine (8oxodG) is a major lesion resulting from oxidative stress and found in both DNA and dNTP pools. Such a lesion is usually removed from DNA by the Base Excision Repair (BER), a universally conserved DNA repair pathway. 8oxodG usually adopts the favored and promutagenic syn-conformation at the active site of DNA polymerases, allowing the base to hydrogen bonding with adenine during DNA synthesis. Here, we study the structural determinants that affect the glycosidic torsion-angle of 8oxodGTP at the catalytic active site of the family X DNA polymerase from Bacillus subtilis (PolXBs). We show that, unlike most DNA polymerases, PolXBs exhibits a similar efficiency to stabilize the anti and syn conformation of 8oxodGTP at the catalytic site. Kinetic analyses indicate that at least two conserved residues of the nucleotide binding pocket play opposite roles in the anti/syn conformation selectivity, Asn263 and His255 that favor incorporation of 8oxodGMP opposite dA and dC, respectively. In addition, the presence in PolXBs of Mn(2+)-dependent 3'-phosphatase and 3'-phosphodiesterase activities is also shown. Those activities rely on the catalytic center of the C-terminal Polymerase and Histidinol Phosphatase (PHP) domain of PolXBs and, together with its 3'-5' exonuclease activity allows the enzyme to resume gap-filling after processing of damaged 3' termini.

  18. SURVIVAL EFFICACY OF THE PEGYLATED G-CSFS MAXY-G34 AND NEULASTA IN A MOUSE MODEL OF LETHAL H-ARS, AND RESIDUAL BONE MARROW DAMAGE IN TREATED SURVIVORS

    PubMed Central

    Chua, Hui Lin; Plett, P. Artur; Sampson, Carol H.; Katz, Barry P.; Carnathan, Gilbert W.; MacVittie, Thomas J.; Lenden, Keith; Orschell, Christie M.

    2013-01-01

    In an effort to expand the worldwide pool of available medical countermeasures (MCM) against radiation, the PEGylated G-CSF (PEG-G-CSF) molecules Neulasta and Maxy-G34, a novel PEG-G-CSF designed for increased half-life and enhanced activity compared to Neulasta, were examined in a murine model of the Hematopoietic Syndrome of the Acute Radiation Syndrome (H-ARS), along with the lead MCM for licensure and stockpiling, G-CSF. Both PEG-G-CSFs were shown to retain significant survival efficacy when administered as a single dose 24hr post-exposure, compared to the 16 daily doses of G-CSF required for survival efficacy. Furthermore, 0.1 mg kg−1 of either PEG-G-CSF effected survival of lethally-irradiated mice that was similar to a 10-fold higher dose. The one dose/low dose administration schedules are attractive attributes of radiation MCM given the logistical challenges of medical care in a mass casualty event. Maxy-G34-treated mice that survived H-ARS were examined for residual bone marrow damage (RBMD) up to 9mo post-exposure. Despite differences in Sca-1 expression and cell cycle position in some hematopoietic progenitor phenotypes, Maxy-G34-treated mice exhibited the same degree of hematopoietic stem cell (HSC) insufficiency as vehicle treated H-ARS survivors in competitive transplantation assays of 150 purified Sca-1+cKit+lin-CD150+ cells. These data suggest that Maxy-G34, at the dose, schedule, and time frame examined, did not mitigate RBMD, but significantly increased survival from H-ARS at one-tenth the dose previously tested, providing strong support for advanced development of Maxy-G34, as well as Neulasta, as MCM against radiation. PMID:24276547

  19. Residual Cap

    NASA Image and Video Library

    2006-05-10

    This MOC image shows a summertime view of the south polar residual cap of Mars. In this image, mesas composed largely of solid carbon dioxide are separated from one another by irregularly-shaped depressions

  20. 77 FR 4890 - Damage Tolerance and Fatigue Evaluation for Composite Rotorcraft Structures, and Damage Tolerance...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-01

    ... static strength of composite rotorcraft structures using a damage tolerance evaluation, or a fatigue... regulations to require evaluation of fatigue and residual static strength of composite rotorcraft...

  1. X-ray spectroscopy of warm and hot electron components in the CAPRICE source plasma at EIS testbench at GSI

    NASA Astrophysics Data System (ADS)

    Mascali, D.; Celona, L.; Maimone, F.; Maeder, J.; Castro, G.; Romano, F. P.; Musumarra, A.; Altana, C.; Caliri, C.; Torrisi, G.; Neri, L.; Gammino, S.; Tinschert, K.; Spaedtke, K. P.; Rossbach, J.; Lang, R.; Ciavola, G.

    2014-02-01

    An experimental campaign aiming to detect X radiation emitted by the plasma of the CAPRICE source - operating at GSI, Darmstadt - has been carried out. Two different detectors (a SDD - Silicon Drift Detector and a HpGe - hyper-pure Germanium detector) have been used to characterize the warm (2-30 keV) and hot (30-500 keV) electrons in the plasma, collecting the emission intensity and the energy spectra for different pumping wave frequencies and then correlating them with the CSD of the extracted beam measured by means of a bending magnet. A plasma emissivity model has been used to extract the plasma density along the cone of sight of the SDD and HpGe detectors, which have been placed beyond specific collimators developed on purpose. Results show that the tuning of the pumping frequency considerably modifies the plasma density especially in the warm electron population domain, which is the component responsible for ionization processes: a strong variation of the plasma density near axis region has been detected. Potential correlations with the charge state distribution in the plasma are explored.

  2. Summary of the HypHI Phase 0 experiment and future plans with FRS at GSI (FAIR Phase 0)

    NASA Astrophysics Data System (ADS)

    Saito, T. R.; Rappold, C.; Bertini, O.; Bianchin, S.; Bozkurt, V.; Geissel, H.; Kavatsyuk, M.; Kim, E.; Ma, Y.; Maas, F.; Minami, S.; Nakajima, D.; Nociforo, C.; Özel-Tashenov, B.; Pochodzalla, J.; Scheidenberger, C.; Yoshida, K.

    2016-10-01

    Results of the HypHI Phase 0 experiment with the reaction of 6Li+12C at 2 A GeV are summarised. Invariant mass distributions as well as the lifetime measurements for 3ΛH and 4ΛH are discussed. The lifetime values for both the hypernuclei are respectively observed to be 183+42-32 ps and 140+48-33 ps, being significantly shorter than those of the Λ-hyperon. Statistical analyses of existing lifetime data for 3ΛH up to 2014 confirm a significantly short lifetime of 3ΛH, which is not explained by present models. Observed hypernuclear production cross section values for 3ΛH and 4ΛH are also summarised. In addition, observed signals for the final states of d +π- and t +π- are discussed. All the discussions on the results of the HypHI Phase 0 experiment in this article are based on [1-4]. We also present a new proposed experiment with the FRS (FRagment Separator) at GSI (FAIR Phase 0) to improve the precision of the hypernuclear spectroscopy with peripheral heavy ion induced reactions.

  3. Residual microstructure and damage geometry associated with high speed impact crater in Al{sub 2}O{sub 3} and TiB{sub 2} particles reinforced 2024 Al composite

    SciTech Connect

    Guo, Q.; Sun, D.L. Jiang, L.T.; Wu, G.H.; Chen, G.Q.

    2012-04-15

    The resistance of Al{sub 2}O{sub 3} + TiB{sub 2}/2024Al composite to hypervelocity impact was tested by a two-stage light gas gun. The impact damage behaviors of the Al{sub 2}O{sub 3} + TiB{sub 2}/2024Al composite by different-sized Al projectiles with a velocity of 2.49 km/s and the residual microstructures associated with the crater impacted by a 1.2 mm aluminum projectile were investigated by transmission electron microscopy and high-resolution transmission electron microscopy. Both the diameters of craters at front face and spalling areas at back face increased with the aluminum projectile diameter. The diameter of perforation on the 2 mm thick Al{sub 2}O{sub 3} + TiB{sub 2}/Al composite target was zero when impacted by 1.2 mm aluminum projectile and it increased to 2.4 mm when the projectile diameter was 1.5 mm, indicating that the critical perforation diameter of the aluminum projectile was between 1.2 mm and 1.5 mm when the 2 mm thick Al{sub 2}O{sub 3} + TiB{sub 2}/Al composite target was impacted by 2.49 km/s aluminum projectiles. The diameter of perforation increases with the diameter of Al projectile. In addition, under each impact condition, the diameters of craters at front face were smaller than that of spalling areas at back face. Microstructure observations by transmission electron microscopy demonstrated four characteristics: stacking faults around TiB{sub 2} particle and dislocations within the TiB{sub 2} particle; twins in the Al{sub 2}O{sub 3} particle; recrystal grains in 2024 Al matrix; and mixture of amorphous microstructure and nanograins in the matrix. - Highlights: Black-Right-Pointing-Pointer Stacking faults were produced around the edge of TiB{sub 2} particle after impact. Black-Right-Pointing-Pointer Twins with the twin plane of (2{sup Macron }112) were observed in Al{sub 2}O{sub 3} particle after impact. Black-Right-Pointing-Pointer Recrystal grains with size of 100 nm were formed in aluminum matrix after impact. Black

  4. Low-cost densification of permanent GPS networks for natural hazard mitigation: First tests on GSI's GEONET network

    NASA Astrophysics Data System (ADS)

    Rizos, Chris; Han, Shaowei; Ge, Linlin; Chen, Horng-Yue; Hatanaka, Yuki; Abe, Kaoru

    2000-10-01

    Researchers from The University of New South Wales (UNSW), Australia, and from the Geographical Survey Institute (GSI), Japan, have commenced a joint project to develop, deploy and test an innovative hardware/software system design for an automatic, continuously-operated ground deformation monitoring system based on low-cost GPS receiver technology. Conventional continuously-operated GPS (CGPS) networks, such as the one established in Japan by GSI to precisely measure earth surface movement, are very expensive. The high cost being primarily due to the fact that dual-frequency receivers are used. Japan's nationwide GEONET network is the world's largest, numbering nearly 1000 receiver stations, with an average station spacing of the order of 30 km. In order to densify such CGPS networks (important when high spatial resolution for the monitoring of the deformation phenomenon is required), and to promote the use of the CGPS technique in lesser developed countries, a significantly cheaper system architecture is needed. The proposed design is an integrated, dual-mode network consisting of low-cost, single-frequency GPS receivers across the area of interest, surrounded by a sparser network of dual-frequency GPS receivers. Initial tests of data collected at selected stations in the GEONET network have already shown that through enhanced data processing algorithms a CGPS network containing both single-frequency and dual-frequency receivers would be able to deliver better than centimetre level accuracies, at considerably lower cost than present systems based exclusively on dual-frequency instrumentation. This paper reports the results of the first field test of this new CGPS system design, in the Tsukuba area of Japan, in August 1999. The test network consisted of: (a) several stations of the GEONET network surrounding (b) an inner network of four single-frequency Canadian Marconi GPS receivers installed by UNSW researchers. The data from both the GEONET and the UNSW

  5. RESIDUAL RISK ASSESSMENTS - RESIDUAL RISK ...

    EPA Pesticide Factsheets

    This source category previously subjected to a technology-based standard will be examined to determine if health or ecological risks are significant enough to warrant further regulation for Coke Ovens. These assesments utilize existing models and data bases to examine the multi-media and multi-pollutant impacts of air toxics emissions on human health and the environment. Details on the assessment process and methodologies can be found in EPA's Residual Risk Report to Congress issued in March of 1999 (see web site). To assess the health risks imposed by air toxics emissions from Coke Ovens to determine if control technology standards previously established are adequately protecting public health.

  6. Accessing baryon to meson transition distribution amplitudes in meson production in association with a high invariant mass lepton pair at GSI-FAIR with P¯ANDA

    NASA Astrophysics Data System (ADS)

    Lansberg, J. P.; Pire, B.; Semenov-Tian-Shansky, K.; Szymanowski, L.

    2012-12-01

    Nucleon-antinucleon annihilation into a near backward- (or forward-) produced meson and a high invariant mass lepton pair admits a factorized description in terms of antinucleon (or nucleon) distribution amplitudes and nucleon-to-meson (or antinucleon-to-meson) transition distribution amplitudes. We estimate the cross section of backward (and forward) pion and η-meson production in association with a high invariant mass lepton pair for the kinematical conditions of GSI-FAIR. The cross sections are found to be large enough to be measured with the P¯ANDA detector. Interesting phenomenological applications of the approach are thus expected.

  7. Residual Cap

    NASA Technical Reports Server (NTRS)

    2006-01-01

    10 May 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a summertime view of the south polar residual cap of Mars. In this image, mesas composed largely of solid carbon dioxide are separated from one another by irregularly-shaped depressions. The variation in brightness across this scene is a function of several factors including, but not limited to, varying proportions of dust and solid carbon dioxide, undulating topography, and differences in the roughness of the slopes versus the flat surfaces.

    Location near: 86.7oS, 343.3oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  8. Spallation residues in the reaction {sup 56}Fe+p at 0.3A,0.5A,0.75A,1.0A, and 1.5A GeV

    SciTech Connect

    Villagrasa-Canton, C.; Boudard, A.; Ducret, J.-E.; Fernandez, B.; Leray, S.; Volant, C.; Audouin, L.; Bacri, C.-O.; Ferrant, L.; Rejmund, F.

    2007-04-15

    The spallation residues produced in the bombardment of {sup 56}Fe at 1.5A,1.0A,0.75A,0.5A, and 0.3A GeV on a liquid-hydrogen target have been measured using the reverse kinematics technique and the fragment separator at GSI (Darmstadt). This technique has permitted the full identification in charge and mass of all isotopes produced with cross sections larger than 10{sup -2} mb down to Z=8. Their individual production cross sections and recoil velocities at the five energies are presented. Production cross sections are compared with previously existing data and with empirical parametric formulas, often used in cosmic-ray astrophysics. The experimental data are also extensively compared with the results of different combinations of intranuclear cascade and deexcitation models. It is shown that the yields of the lightest isotopes cannot be accounted for by standard evaporation models. The GEMINI model, which includes an asymmetric fission decay mode, gives an overall good agreement with the data. These experimental data can be directly used for the estimation of composition modifications and damages in materials containing iron in spallation sources. They are also useful for improving high-precision cosmic-ray measurements.

  9. Damage accumulation in ceramics during ion implantation

    SciTech Connect

    McHargue, C.J.; Farlow, G.C.; Begun, G.M.; Williams, J.M.; White, C.W.; Appleton, B.R.; Sklad, P.S.; Angelini, P.

    1985-01-01

    The damage structures of ..cap alpha..-Al/sub 2/O/sub 3/ and ..cap alpha..-SiC were examined as functions of ion implantation parameters using Rutherford backscattering-channeling, analytical electron microscopy, and Raman spectroscopy. Low temperatures or high fluences of cations favor formation of the amorphous state. At 300/sup 0/K, mass of the bombarding species has only a small effect on residual damage, but certain ion species appear to stabilize the damage microstructure and increase the rate of approach to the amorphous state. The type of chemical bonding present in the host lattice is an important factor in determining the residual damage state.

  10. Studies on fission with ALADIN. Precise and simultaneous measurement of fission yields, total kinetic energy and total prompt neutron multiplicity at GSI

    NASA Astrophysics Data System (ADS)

    Martin, Julie-Fiona; Taieb, Julien; Chatillon, Audrey; Bélier, Gilbert; Boutoux, Guillaume; Ebran, Adeline; Gorbinet, Thomas; Grente, Lucie; Laurent, Benoit; Pellereau, Eric; Alvarez-Pol, Héctor; Audouin, Laurent; Aumann, Thomas; Ayyad, Yassid; Benlliure, Jose; Casarejos, Enrique; Cortina Gil, Dolores; Caamaño, Manuel; Farget, Fanny; Fernández Domínguez, Beatriz; Heinz, Andreas; Jurado, Beatriz; Kelić-Heil, Aleksandra; Kurz, Nikolaus; Nociforo, Chiara; Paradela, Carlos; Pietri, Stéphane; Ramos, Diego; Rodríguez-Sànchez, Jose-Luis; Rodríguez-Tajes, Carme; Rossi, Dominic; Schmidt, Karl-Heinz; Simon, Haik; Tassan-Got, Laurent; Vargas, Jossitt; Voss, Bernd; Weick, Helmut

    2015-12-01

    A novel technique for fission studies, based on the inverse kinematics approach, is presented. Following pioneering work in the nineties, the SOFIA Collaboration has designed and built an experimental set-up dedicated to the simultaneous measurement of isotopic yields, total kinetic energies and total prompt neutron multiplicities, by fully identifying both fission fragments in coincidence, for the very first time. This experiment, performed at GSI, permits to study the fission of a wide variety of fissioning systems, ranging from mercury to neptunium, possibly far from the valley of stability. A first experiment, performed in 2012, has provided a large array of unprecedented data regarding the nuclear fission process. An excerpt of the results is presented. With this solid starter, further improvements of the experimental set-up are considered, which are consistent with the expected developments at the GSI facility, in order to measure more fission observables in coincidence. The completeness reached in the SOFIA data, permits to scrutinize the correlations between the interesting features of fission, offering a very detailed insight in this still unraveled mechanism.

  11. Comment on 'Time modulation of K-shell electron capture decay rates of H-like heavy ions at GSI experiments.'

    SciTech Connect

    Lipkin, H. J.; Physics; Weizmann Inst. of Science; Tel Aviv Univ.

    2010-04-16

    A Comment on the Letter by A.N. Ivanov and P. Kienle, Physical Review Letters volume 103, Issue 6, 062502 (2009). The authors of the Letter offer a Reply to experimental data at GSI, the rates of the number of daughter ions, produced by the nuclear K shell electron capture decays of the H-like heavy ions with one electron in the K shell, such as {sup 140}Pr{sup 58+}, {sup 142}Pm{sup 60+}, and {sup 122}I{sup 52+}, are modulated in time with periods T{sub EC} of the order of a few seconds, obeying an A scaling T{sub EX}=A/20 s, where A is the mass number of the mother nuclei, and with amplitudes a{sub d {sup EC}}{approx}0.21. We show that these data can be explained in terms of the interference of two massive neutrino mass eigenstates. The appearance of the interference term is due to overlap of massive neutrino mass eigenstate energies and of the wave functions of the daughter ions in two-body decay channels, caused by the energy and momentum uncertainties introduced by time differential detection of the daughter ions in GSI experiments.

  12. residue and shunting pinholes

    NASA Astrophysics Data System (ADS)

    Gorji, Nima E.

    2014-09-01

    The present work considers two observable phenomena through the experimental fabrication and electrical characterization of the rf-sputtered CdS/CdTe thin film solar cells that extremely reduce the overall conversion efficiency of the device: CdCl2 residue on the surface of the semiconductor and shunting pinholes. The former happens through nonuniform treatment of the As-deposited solar cells before annealing at high temperature and the latter occurs by shunting pinholes when the cell surface is shunted by defects, wire-like pathways or scratches on the metallic back contact caused from the external contacts. Such physical problems may be quite common in the experimental activities and reduce the performance down to 4-5 % which leads to dismantle the device despite its precise fabrication. We present our electrical characterization on the samples that received wet CdCl2 surface treatment (uniform or nonuniform) and are damaged by the pinholes.

  13. Chapter 6: Fire damage of wood structures

    Treesearch

    B. Kukay; R.H. White; F. Woeste

    2012-01-01

    Depending on the severity, fire damage can compromise the structural integrity of wood structures such as buildings or residences. Fire damage of wood structures can incorporate several models that address (1) the type, cause, and spread of the fire, (2) the thermal gradients and fire-resistance ratings, and (3) the residual load capacity (Figure 6.1). If there is a...

  14. β-decay and β-delayed Neutron Emission Measurements at GSI-FRS Beyond N=126, for r-process Nucleosynthesis

    SciTech Connect

    Caballero-Folch, R.; Domingo-Pardo, C.; Cortès, G.; Taín, J.L.; Agramunt, J.; Algora, A.; Ameil, F.; Ayyad, Y.; Benlliure, J.; Bowry, M.; Calviño, F.; Cano-Ott, D.; Davinson, T.; and others

    2014-06-15

    New measurements of very exotic nuclei in the neutron-rich region beyond N=126 have been performed at the GSI facility with the fragment separator (FRS). The aim of the experiment is to determine half-lives and β-delayed neutron emission branching ratios of isotopes of Hg, Tl and Pb in this region. This contribution summarizes final counting statistics for identification and for implantation, as well as the present status of the data analysis of the half-lives. In summary, isotopes of Pt, Au, Hg, Tl, Pb, Bi, Po, At, Rn and Fr were clearly identified and several of them ({sup 208-211}Hg, {sup 211-215}Tl, {sup 214-218}Pb) were implanted with enough statistics to determine their half-lives. About half of them are expected to be neutron emitters, in such cases it will become possible to obtain the neutron emission probabilities, Pn.

  15. Effects of Kamdhenu Ark and Active Immunization by Gonadotropin Releasing Hormone Conjugate (GnRH-BSA) on Gonadosomatic Indices (GSI) and Sperm Parameters in Male Mus musculus

    PubMed Central

    Ganaie, Javid Ahmad; Gautam, Varsha; Shrivastava, Vinoy Kumar

    2011-01-01

    Background Active immunization against GnRH decreases the secretion of gonadotropins and causes cessation of gonadal function, thereby, inducing infertility. Based on the immunoenhancing activity of Kamdhenu ark (distilled cow urine), this study was performed to evaluate its effects on the gonadosomatic indices (GSI) and sperm parameters in male mice receiving a GnRH contraceptive vaccine. Methods Sixty adult male mice of Parke's strain were divided into three groups of twenty. Group I served as the controls, while group II was immunized by GnRH-BSA conjugate (50/0.2/35 µg/ml/g BW) by four intraperitoneal injections at different intervals on days 1, 30, 60 and 90. However, group III was supplemented daily by oral Kamdhenu ark (100 ppm) along with GnRH-BSA immunizations. The animals were sacrificed after 30, 60, 90 and 120 days and their testis and epididymis were dissected out weighed and semen analysis was performed. Results GSI values, sperm motility, sperm count and sperm morphology in male Mus musculus were decreased significantly in all the experimental groups as compared to the control group (p<0.01). Kamdhenu ark significantly enhanced the effect of GnRH vaccine on the aforesaid parameters especially in 90 and 120 days treated groups (p<0.05). Conclusion The changes witnessed in sperm parameters suggested that the GnRH-BSA immunization suppressed the activities of gonadotropins and testosterone directly through hypothalamo-hypophysial-gonadal axis and indirectly by acting on the testes which may modulate the sperm morphology, sperm count and motility. However, Kamdhenu ark seems to have enhanced these effects because of its immune-modulatory properties too. PMID:23926493

  16. Measurement of the fluence response of the GSI neutron ball dosemeter in the energy range from thermal to 19 MeV.

    PubMed

    Fehrenbacher, G; Kozlova, E; Gutermuth, F; Radon, T; Schütz, R; Nolte, R; Böttger, R

    2007-01-01

    At high-energy particle accelerators, area monitoring needs to be performed in a wide range of neutron energies. In principle, neutrons occur from thermal energies up to the energy of the accelerated ions, which is for the present GSI (Gesellschaft für Schwerionenforschung) accelerator facility approximately 1-2 GeV per nucleon. There are no passive dosemeters available, which are designed for the use at high-energy accelerators. At GSI, a neutron dosemeter was developed, which is suitable for the measurement of high-energy neutron radiation by the insertion of a lead layer around Thermoluminescence (TL) detection elements (pairs of TL 600/700) at the centre of the dosemeter. The design of the sphere was derived from the construction of the extended range rem-counters for the measurement of ambient dose equivalent H(10). In this work, the dosemeter fluence response was measured in the quasi-monoenergetic neutron fields of the accelerator facility of the PTB in Braunschweig and in the thermal neutron field of the GKSS research reactor FRG-1 in Geesthacht. For the accelerator measurements, the reactions (7)Li(p,n)(7)Be, (3)H(p,n)(3)He and (2)H(d,n)(3)He were used to produce neutron fields with energy peaks between 144 keV and 19 MeV. The measured fluence responses are 27% too low for thermal energies and show an agreement with approximately 14% for the accelerator produced neutron fields related to the computed fluence responses (MCNP, FLUKA calculations). The measured as well as the computed fluence responses of the dosemeter are compared with the corresponding conversion coefficients.

  17. Protein damage, radiation sensitivity and aging.

    PubMed

    Radman, Miroslav

    2016-08-01

    This paper promotes a concept that protein damage determines radiation resistance and underlies aging and age-related diseases. The first bottleneck in cell recovery from radiation damage is functional (proteome) rather than informational (DNA), since prokaryotic and eukaryotic cell death correlates with incurred protein, but not DNA, damage. Proteome protection against oxidative damage determines survival after ionizing or UV irradiation, since sufficient residual proteome activity is required to turn on the DNA damage response activating DNA repair and protein renewal processes. Extreme radiation and desiccation resistance of rare bacterial and animal species is accounted for by exceptional constitutive proteome protection against oxidative damage. After excessive radiation their well-protected proteome faithfully reconstitutes a transcription-competent genome from hundreds of DNA fragments. The observation that oxidative damage targeted selectively to cellular proteins results in aging-like phenotypes suggests that aging and age-related diseases could be phenotypic consequences of proteome damage patterns progressing with age.

  18. Damage Tolerance of Composite Laminates from an Empirical Perspective

    NASA Technical Reports Server (NTRS)

    Nettles, Alan T.

    2009-01-01

    Damage tolerance consists of analysis and experimentation working together. Impact damage is usually of most concern for laminated composites. Once impacted, the residual compression strength is usually of most interest. Other properties may be of more interest than compression (application dependent). A damage tolerance program is application specific (not everyone is building aircraft). The "Building Block Approach" is suggested for damage tolerance. Advantage can be taken of the excellent fatigue resistance of damaged laminates to save time and costs.

  19. Compressive residual strength of graphite/epoxy laminates after impact

    NASA Technical Reports Server (NTRS)

    Guy, Teresa A.; Lagace, Paul A.

    1992-01-01

    The issue of damage tolerance after impact, in terms of the compressive residual strength, was experimentally examined in graphite/epoxy laminates using Hercules AS4/3501-6 in a (+ or - 45/0)(sub 2S) configuration. Three different impactor masses were used at various velocities and the resultant damage measured via a number of nondestructive and destructive techniques. Specimens were then tested to failure under uniaxial compression. The results clearly show that a minimum compressive residual strength exists which is below the open hole strength for a hole of the same diameter as the impactor. Increases in velocity beyond the point of minimum strength cause a difference in the damage produced and cause a resultant increase in the compressive residual strength which asymptotes to the open hole strength value. Furthermore, the results show that this minimum compressive residual strength value is independent of the impactor mass used and is only dependent upon the damage present in the impacted specimen which is the same for the three impactor mass cases. A full 3-D representation of the damage is obtained through the various techniques. Only this 3-D representation can properly characterize the damage state that causes the resultant residual strength. Assessment of the state-of-the-art in predictive analysis capabilities shows a need to further develop techniques based on the 3-D damage state that exists. In addition, the need for damage 'metrics' is clearly indicated.

  20. Right Hemisphere Brain Damage

    MedlinePlus

    ... Language and Swallowing / Disorders and Diseases Right Hemisphere Brain Damage [ en Español ] What is right hemisphere brain ... right hemisphere brain damage ? What is right hemisphere brain damage? Right hemisphere brain damage (RHD) is damage ...

  1. The decays of three top contributors to the reactor ve high-energy spectrum, 92Rb, 96gsY, and 142Cs, studied with total absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Rasco, Bertis; MTAS Collaboration

    2016-09-01

    We report total absorption spectroscopy measurements of 92Rb, 96gsY, and 142Cs β decays, which are the most important contributors to the high energy ve spectral shape in nuclear reactors. The measurements were performed with the NaI(Tl) based Modular Total Absorption Spectrometer (MTAS). MTAS was constructed specifically to measure improved β-decay feeding patterns from neutron-rich nuclei, because it is difficult to measure β-decay feeding intensities with high energy precision γ-ray measurements due to the low efficiency of high precision detectors. Besides the impact to the high energy ve spectral shape in nuclear reactors, there are several other important applications of improved measurements of β-decay feeding patterns by total absorption spectroscopy; improve understanding of elemental abundances in the universe, help with stockpile stewardship, contribute to understanding of underlying nuclear structure, and improve measurements of decay heat. We will demonstrate some of the techniques for analyzing MTAS γ-decay data. This research was also sponsored by the Office of Nuclear Physics, U. S. Department of Energy under Contracts DE-AC05-00OR22725, DE-FG02-96ER40983, DE-FG02-96ER40978, and by the Polish National Science Center under Contract UMO-2013/08/T/ST2/00624.

  2. Modeling event building architecture for the triggerless data acquisition system for PANDA experiment at the HESR facility at FAIR/GSI

    NASA Astrophysics Data System (ADS)

    Korcyl, K.; Konorov, I.; Kühn, W.; Schmitt, L.

    2012-12-01

    A novel architecture is being proposed for the data acquisition and trigger system of the PANDA experiment at the HESR facility at FAIR/GSI. The experiment will run without hardware trigger signal using timestamps to correlate detector data from a given time window. The broad physics program in combination with the high rate of 2 * 107 interactions per second requires very selective filtering algorithms accessing information from many detectors. Therefore the effective filtering will happen later than in today's systems ie. after the event building. To assess that, the complete architecture will be built of two stages: the data concentrator stage providing event building and the rate reduction stage. For the former stage, which requires a throughput of 100 GB/s to perform event building, we propose two layers of ATCA crates filled with Compute Nodes - modules designed at IHEP and University of Giessen for trigger and data acquisition systems. Currently each board is equipped with 5 Virtex4 FX60 FPGAs and high bandwidth connectivity is provided by 8 front panel RocketIO ports and 12 backplane ports for the inter-module communication. We designed simplified models of the components of the architecture and using the SystemC library as support for the discrete event simulations, demonstrate the expected throughput of the full-size system. We also show impact of some architectural choices and key parameters on the architecture's performance.

  3. Nuclear-matter radius studies from 58Ni(α ,α ) experiments at the GSI Experimental Storage Ring with the EXL facility

    NASA Astrophysics Data System (ADS)

    Zamora, J. C.; Aumann, T.; Bagchi, S.; Bönig, S.; Csatlós, M.; Dillmann, I.; Dimopoulou, C.; Egelhof, P.; Eremin, V.; Furuno, T.; Geissel, H.; Gernhäuser, R.; Harakeh, M. N.; Hartig, A.-L.; Ilieva, S.; Kalantar-Nayestanaki, N.; Kiselev, O.; Kollmus, H.; Kozhuharov, C.; Krasznahorkay, A.; Kröll, Th.; Kuilman, M.; Litvinov, S.; Litvinov, Yu. A.; Mahjour-Shafiei, M.; Mutterer, M.; Nagae, D.; Najafi, M. A.; Nociforo, C.; Nolden, F.; Popp, U.; Rigollet, C.; Roy, S.; Scheidenberger, C.; von Schmid, M.; Steck, M.; Streicher, B.; Stuhl, L.; Thürauf, M.; Uesaka, T.; Weick, H.; Winfield, J. S.; Winters, D.; Woods, P. J.; Yamaguchi, T.; Yue, K.; Zenihiro, J.

    2017-09-01

    A novel method for measuring nuclear reactions in inverse kinematics with stored ion beams was successfully used to extract the nuclear-matter radius of 58Ni. The experiment was performed at the experimental heavy-ion storage ring at the GSI facility using a stored 58Ni beam at energies of 100 and 150 MeV/u and an internal helium gas-jet target. Elastically scattered α -recoils at low momentum transfers were measured with an in-ring detector system compatible with ultrahigh vacuum. Experimental angular distributions were fitted using density-dependent optical model potentials within the eikonal approximation. This permitted the extraction of the point-matter root-mean-square radius of 58Ni with an average value of 3.70(7) fm. Results from this work are in good agreement with several experiments performed in the past in normal kinematics. This pioneering experiment demonstrates a major breakthrough towards future investigations with far-from-stability stored beams using the present technique.

  4. Antioxidant properties of roasted coffee residues.

    PubMed

    Yen, Wen-Jye; Wang, Bor-Sen; Chang, Lee-Wen; Duh, Pin-Der

    2005-04-06

    The antioxidant activity of roasted coffee residues was evaluated. Extraction with four solvents (water, methanol, ethanol, and n-hexane) showed that water extracts of roasted coffee residues (WERCR) produced higher yields and gave better protection for lipid peroxidation. WERCR showed a remarkable protective effect on oxidative damage of protein. In addition, WERCR showed scavenging of free radicals as well as the reducing ability and to bind ferrous ions, indicating that WERCR acts as both primary and secondary antioxidants. The HPLC analyses showed that phenolic acids (chlorogenic acid and caffeic acid) and nonphenolic compounds [caffeine, trigonelline, nicotinic acid, and 5-(hydroxymethyl)furfuraldehyde] remained in roasted coffee residues. These compounds showed a protective effect on a liposome model system. The concentrations of flavonoids and polyphenolic compounds in roasted coffee residues were 8,400 and 20,400 ppm, respectively. In addition, the Maillard reaction products (MRPs) remaining in roasted coffee residues were believed to show antioxidant activity. These data indicate that roasted coffee residues have excellent potential for use as a natural antioxidant source because the antioxidant compounds remained in roasted coffee residues.

  5. Residual thermal stresses in composites for dimensionally stable spacecraft applications

    NASA Technical Reports Server (NTRS)

    Bowles, David E.; Tompkins, Stephen S.; Funk, Joan G.

    1992-01-01

    An overview of NASA LaRC's research on thermal residual stresses and their effect on the dimensional stability of carbon fiber reinforced polymer-matrix composites is presented. The data show that thermal residual stresses can induce damage in polymer matrix composites and significantly affect the dimensional stability of these composites by causing permanent residual strains and changes in CTE. The magnitude of these stresses is primarily controlled by the laminate configuration and the applied temperature change. The damage caused by thermal residual stresses initiates at the fiber/matrix interface and micromechanics level analyses are needed to accurately predict it. An increased understanding of fiber/matrix interface interactions appears to be the best approach for improving a composite's resistance to thermally induced damage.

  6. Residual thermal stresses in composites for dimensionally stable spacecraft applications

    NASA Technical Reports Server (NTRS)

    Bowles, David E.; Tompkins, Stephen S.; Funk, Joan G.

    1992-01-01

    An overview of NASA LaRC's research on thermal residual stresses and their effect on the dimensional stability of carbon fiber reinforced polymer-matrix composites is presented. The data show that thermal residual stresses can induce damage in polymer matrix composites and significantly affect the dimensional stability of these composites by causing permanent residual strains and changes in CTE. The magnitude of these stresses is primarily controlled by the laminate configuration and the applied temperature change. The damage caused by thermal residual stresses initiates at the fiber/matrix interface and micromechanics level analyses are needed to accurately predict it. An increased understanding of fiber/matrix interface interactions appears to be the best approach for improving a composite's resistance to thermally induced damage.

  7. Damaged Skylab

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The Saturn V vehicle, carrying the unmarned orbital workshop for the Skylab-1 mission, lifted off successfully and all systems performed normally. Sixty-three seconds into the flight, engineers in the operation support and control center saw an unexpected telemetry indication that signalled that damages occurred on one solar array and the micrometeoroid shield during the launch. The micrometeoroid shield, a thin protective cylinder surrounding the workshop protecting it from tiny space particles and the sun's scorching heat, ripped loose from its position around the workshop. This caused the loss of one solar wing and jammed the other. Still unoccupied, the Skylab was stricken with the loss of the heat shield and sunlight beat mercilessly on the lab's sensitive skin. Internal temperatures soared, rendering the station uninhabitable, threatening foods, medicines, films, and experiments. This image, taken during a fly-around inspection by the Skylab-2 crew, shows a crippled Skylab in orbit. The crew found their home in space to be in serious shape; the heat shield gone, one solar wing gone, and the other jammed. The Marshall Space Flight Center (MSFC) developed, tested, rehearsed, and approved three repair options. These options included a parasol sunshade and a twin-pole sunshade to restore the temperature inside the workshop, and a set of metal cutting tools to free the jammed solar panel.

  8. Isotopic production cross sections of residual nuclei in the spallation reaction 136Xe(200 A MeV)+p

    NASA Astrophysics Data System (ADS)

    Paradela, C.; Tassan-Got, L.; Benlliure, J.; Rodríguez-Sánchez, J. L.; Audouin, L.; Boudard, A.; Casarejos, E.; Enqvist, T.; Ducret, J. E.; Farget, F.; Fernández-Domínguez, B.; Fernández Ordóñez, M.; Giot, L.; Heinz, A.; Henzl, V.; Henzlova, D.; Kelić-Heil, A.; Lafriaskh, A.; Leray, S.; Napolitani, P.; Pereira, J.; Pérez-Loureiro, D.; Ricciardi, M. V.; Stéphan, C.; Schmidt, K.-H.; Schmitt, C.; Villagrasa, C.; Volant, C.; Yordanov, O.

    2017-04-01

    The residual nuclei produced in the spallation reaction of 136Xe nuclei at 200 A MeV on protons have been studied by measuring the isotopic distributions for the elements from cadmium (Z =48 ) to cesium (Z =55 ) by using the fragment separator (FRS) spectrometer at GSI and the inverse kinematics technique. This is one of the few measurements performed at such a low projectile energy, close to the validity limit for intranuclear cascade models such as incl or isabel. The experimental results have been compared to these intranuclear cascade codes coupled to the evaporation code abla. Both code combinations reproduce qualitatively the measured isotopic distributions; however, both underestimate the production of residues with mass numbers between 126 and 134. The measured cross sections are of interest for the planning of future radioactive beam or neutron source facilities.

  9. Nondestructive monitoring damage in composites using scanning laser acoustic microscopy

    NASA Technical Reports Server (NTRS)

    Wey, A. C.; Kessler, L. W.; Dos Reis, H. L. M.

    1992-01-01

    Several Nicalon fiber reinforced LAS (lithium alumino-silicate) glass matrix composites were tested to study the relation between the residual strength and the different amounts of damage. The samples were fatigued by four-point cyclic loading at a 5 Hz rate at 500 C for a different number of cycles. 10 MHz scanning laser acoustic microscope (SLAM) images were taken to monitor damage on the samples. Our SLAM results indicate that there were defects already existing throughout the sample before fatigue, and the resultant damage pattern from fatigue could be related to the initial defect distribution in the sample. Finally, the fatigued samples were fractured and the residual strength data could not be explained by the cyclic fatigue alone. Rather, the damage patterns evident in the SLAM images were needed to explain the scatter in the data. The results show that SLAM is useful in nondestructively monitoring damage and estimating residual strength of fatigued ceramic composites.

  10. Randomizing the unfolded state of peptides (and proteins) by nearest neighbor interactions between unlike residues.

    PubMed

    Toal, Siobhan E; Kubatova, Nina; Richter, Christian; Linhard, Verena; Schwalbe, Harald; Schweitzer-Stenner, Reinhard

    2015-03-23

    To explore the influence of nearest neighbors on conformational biases in unfolded peptides, we combined vibrational and 2D NMR spectroscopy to obtain the conformational distributions of selected "GxyG" host-guest peptides in aqueous solution: GDyG, GSyG, GxLG, GxVG, where x/y=A, K, L, V. Large changes of conformational propensities were observed due to nearest-neighbor interactions, at variance with the isolated pair hypothesis. We found that protonated aspartic acid and serine lose their above-the-average preference for turn-like structures in favor of polyproline II (pPII) populations in the presence of neighbors with bulky side chains. Such residues also decrease the above-the-average pPII preference of alanine. These observations suggest that the underlying mechanism involves a disruption of the hydration shell. Thermodynamic analysis of (3) J(H(N) ,H(α) ) (T) data for each x,y residue reveals that modest changes in the conformational ensemble masks larger changes of enthalpy and entropy governing the pPII↔β equilibrium indicating a significant residue dependent temperature dependence of the peptides' conformational ensembles. These results suggest that nearest-neighbor interactions between unlike residues act as conformational randomizers close to the enthalpy-entropy compensation temperature, eliminating intrinsic biases in favor of largely balanced pPII/β dominated ensembles at physiological temperatures. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Utilization of oak residues

    Treesearch

    Richard C. Allison

    1971-01-01

    Residues should be thought of as a raw material for specific uses rather than as a waste. Fines and solid wood residues are usually kept separated in waste-collection system, but species are rarely kept separated. The properties of each species dictate what uses can be made of them. Quantity, location, cost, moisture content, physical size, and presence of foreign...

  12. New elements produced at GSI

    SciTech Connect

    Hofmann, Sigurd

    1998-12-21

    In two series of experiments at SHIP, six new elements (Z=107-112) were synthesized via fusion reactions using lead or bismuth targets and 1n-deexcitation channels. The isotopes were unambiguously identified by means of {alpha}-{alpha} correlations. Not fission, but alpha decay is the dominant decay mode. Cross-sections decrease by two orders of magnitude from bohrium (Z=107) to element 112, for which a cross-section of 1 pb was measured. Based on our results, it is likely that the production of isotopes of element 114 close to the island of spherical SuperHeavy Elements (SHE) could be achieved by fusion reactions using {sup 208}Pb targets. Systematic studies of the reaction cross-sections indicate that the transfer of nucleons is an important process for the initiation of fusion. The data allow for the fixing of a narrow energy window for the production of SHE using 1n-emission channels. The likelihood of broadening the energy window by investigation of radiative capture reactions, use of neutron deficient projectile isotopes and use of actinide targets is discussed.

  13. Damage of hybrid composite laminates

    NASA Astrophysics Data System (ADS)

    Haery, Haleh A.; Kim, Ho Sung

    2013-08-01

    Hybrid laminates consisting of woven glass fabric/epoxy composite plies and woven carbon fabric/epoxy composite plies are studied for fatigue damage and residual strength. A theoretical framework based on the systems approach is proposed as a guide to deal with the complexity involving uncertainties and a large number of variables in the hybrid composite system. A relative damage sensitivity factor expression was developed for quantitative comparisons between non-hybrid and hybrid composites. Hypotheses derived from the theoretical framework were tested and verified. The first hypothesis was that the difference between two different sets of properties produces shear stress in interface between carbon fibre reinforced plastics (CRP) and glass fibre reinforced plastics (GRP), and eventually become a source for CRP/GRP interfacial delamination or longitudinal cracking. The second hypothesis was that inter-fibre bundle delamination occurs more severely to CRP sub-system than GRP sub-system.

  14. Concepts for improving the damage tolerance of composite compression panels

    NASA Technical Reports Server (NTRS)

    Rhodes, M. D.; Williams, J. G.

    1981-01-01

    The results of an experimental evaluation of graphite-epoxy composite compression panel impact damage tolerance and damage propagation arrest concepts are reported. The tests were conducted on flat plate specimens and blade-stiffened structural panels such as those used in commercial aircraft wings, and the residual strength of damaged specimens and their sensitivity to damage while subjected to in-plane compression loading were determined. Results suggest that matrix materials that fail by delamination have the lowest damage tolerance, and it is concluded that alternative matrix materials with transverse reinforcement to suppress the delamination failure mode and yield the higher-strain value transverse shear crippling mode should be developed.

  15. TENORM: Coal Combustion Residuals

    EPA Pesticide Factsheets

    Burning coal in boilers to create steam for power generation and industrial applications produces a number of combustion residuals. Naturally radioactive materials that were in the coal mostly end up in fly ash, bottom ash and boiler slag.

  16. Surrogate Modeling of High-Fidelity Fracture Simulations for Real-Time Residual Strength Predictions

    NASA Technical Reports Server (NTRS)

    Spear, Ashley D.; Priest, Amanda R.; Veilleux, Michael G.; Ingraffea, Anthony R.; Hochhalter, Jacob D.

    2011-01-01

    A surrogate model methodology is described for predicting in real time the residual strength of flight structures with discrete-source damage. Starting with design of experiment, an artificial neural network is developed that takes as input discrete-source damage parameters and outputs a prediction of the structural residual strength. Target residual strength values used to train the artificial neural network are derived from 3D finite element-based fracture simulations. A residual strength test of a metallic, integrally-stiffened panel is simulated to show that crack growth and residual strength are determined more accurately in discrete-source damage cases by using an elastic-plastic fracture framework rather than a linear-elastic fracture mechanics-based method. Improving accuracy of the residual strength training data would, in turn, improve accuracy of the surrogate model. When combined, the surrogate model methodology and high-fidelity fracture simulation framework provide useful tools for adaptive flight technology.

  17. Decays of the Three Top Contributors to the Reactor ν[over ¯]_{e} High-Energy Spectrum, ^{92}Rb, ^{96gs}Y, and ^{142}Cs, Studied with Total Absorption Spectroscopy.

    PubMed

    Rasco, B C; Wolińska-Cichocka, M; Fijałkowska, A; Rykaczewski, K P; Karny, M; Grzywacz, R K; Goetz, K C; Gross, C J; Stracener, D W; Zganjar, E F; Batchelder, J C; Blackmon, J C; Brewer, N T; Go, S; Heffron, B; King, T; Matta, J T; Miernik, K; Nesaraja, C D; Paulauskas, S V; Rajabali, M M; Wang, E H; Winger, J A; Xiao, Y; Zachary, C J

    2016-08-26

    We report total absorption spectroscopy measurements of ^{92}Rb, ^{96gs}Y, and ^{142}Cs β decays, which are the most important contributors to the high energy ν[over ¯]_{e} spectral shape in nuclear reactors. These three β decays contribute 43% of the ν[over ¯]_{e} flux near 5.5 MeV emitted by nuclear reactors. This ν[over ¯]_{e} energy is particularly interesting due to spectral features recently observed in several experiments including the Daya Bay, Double Chooz, and RENO Collaborations. Measurements were conducted at Oak Ridge National Laboratory by means of proton-induced fission of ^{238}U with on-line mass separation of fission fragments and the Modular Total Absorption Spectrometer. We observe a β-decay pattern that is similar to recent measurements of ^{92}Rb, with a ground-state to ground-state β feeding of 91(3)%. We verify the ^{96gs}Y ground-state to ground-state β feeding of 95.5(20)%. Our measurements substantially modify the β-decay feedings of ^{142}Cs, reducing the β feeding to ^{142}Ba states below 2 MeV by 32% when compared with the latest evaluations. Our results increase the discrepancy between the observed and the expected reactor ν[over ¯]_{e} flux between 5 and 7 MeV, the maximum excess increases from ∼10% to ∼12%.

  18. Continuum damage mechanics (CDM) modelling demonstrates that ligament fatigue damage accumulates by different mechanisms than creep damage.

    PubMed

    Schwab, Timothy D; Johnston, Clifton R; Oxland, Thomas R; Thornton, Gail M

    2007-01-01

    Ligaments can be subjected to creep and fatigue damage when loaded to higher than normal stresses due to injury of a complementary joint restraint. Continuum damage mechanics (CDM) assumes that diffuse damage accumulates in a material, thereby reducing the effective cross-sectional area and leading to eventual rupture. The objective of this study was to apply CDM modelling to ligament creep and fatigue to reveal mechanisms of damage. Fatigue was modelled by cyclically varying the stress in the creep model. A few novel approaches were used. First, area reduction was not assumed equal to modulus reduction; thus, allowing damaged fibres to potentially contribute to load-bearing through the extracellular matrix. Modulus ratio was related to area reduction using residual strength. Second, damage rate was not assumed constant but rather was determined directly from the modulus ratio change with respect to time. Third, modulus ratio was normalized to maximum modulus to avoid artificial calculation of negative damage. With this approach, the creep time-to-rupture was predicted with -4% error at 60% UTS and -13% error at 30% UTS. At 15% UTS, no test was undertaken experimentally for a duration as long as the 24 days predicted theoretically. Oscillating the time-dependent damage in the creep model could not completely explain the fatigue behaviour because the fatigue time-to-rupture was predicted with over 1300% error at all stresses. These results suggest that a cycle-dependent damage mechanism, in addition to a time-dependent one, was responsible for fatigue rupture. Cycle-dependent damage may be an important consideration for rehabilitation activities following injury of a complementary ligament restraint.

  19. Development of a viscoelastic continuum damage model for cyclic loading

    NASA Astrophysics Data System (ADS)

    Sullivan, R. W.

    2008-12-01

    A previously developed spectrum model for linear viscoelastic behavior of solids is used to describe the rate-dependent damage growth of a time dependent material under cyclic loading. Through the use of the iterative solution of a special Volterra integral equation, the cyclic strain history is described. The spectrum-based model is generalized for any strain rate and any uniaxial load history to formulate the damage function. Damage evolution in the body is described through the use of a rate-type evolution law which uses a pseudo strain to express the viscoelastic constitutive equation with damage. The resulting damage function is used to formulate a residual strength model. The methodology presented is demonstrated by comparing the peak values of the computed cyclic strain history as well as the residual strength model predictions to the experimental data of a polymer matrix composite.

  20. Probabilistic Evaluation of Blade Impact Damage

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Abumeri, G. H.

    2003-01-01

    The response to high velocity impact of a composite blade is probabilistically evaluated. The evaluation is focused on quantifying probabilistically the effects of uncertainties (scatter) in the variables that describe the impact, the blade make-up (geometry and material), the blade response (displacements, strains, stresses, frequencies), the blade residual strength after impact, and the blade damage tolerance. The results of probabilistic evaluations results are in terms of probability cumulative distribution functions and probabilistic sensitivities. Results show that the blade has relatively low damage tolerance at 0.999 probability of structural failure and substantial at 0.01 probability.

  1. Modeling and Characterization of Recompressed Damaged Materials

    SciTech Connect

    Becker, R; Belak, J; Campbell, G

    2002-12-16

    Ductile metals subjected to shock loading can develop internal damage through nucleation growth and coalescence of voids. The extent of damage can range from a well-defined spall plane induced by light shocks to more widespread damage caused by strong shocks. Because damage materials are often part of a dynamic system, significant additional deformation can occur in extensively damaged materials. To represent material behavior in simulation codes for stockpile stewardship calculations, both the damage and the recompression processes must be modeled accurately. Currently, no experimentally based models of recompression behavior are available for use in numerical simulations. The goals of this project are to (1) perform recompression experiments on samples containing controlled and well-characterized damage, (2) develop a model capturing the recompression behavior and residual strength based on the experimental data and micro-mechanical models, and (3) implement the model in an Advanced Simulation and Computing (ASCI) code (ALE3D). The recompression model, together with failure models based on underlying physical mechanisms, will provide a more accurate representation of material behavior-information that is needed for simulations of explosively loaded materials such as those required by the Stockpile Stewardship Program.

  2. Logging damage in thinned, young-growth true fir stands in California and recommendations for prevention.

    Treesearch

    Paul E. Aho; Gary Fiddler; Mike. Srago

    1983-01-01

    Logging-damage surveys and tree-dissection studies were made in commercially thinned, naturally established young-growth true fir stands in the Lassen National Forest in northern California. Significant damage occurred to residual trees in stands logged by conventional methods. Logging damage was substantially lower in stands thinned using techniques designed to reduce...

  3. Numerical simulation of damage progression in unidirectional composites

    NASA Astrophysics Data System (ADS)

    Chung, Michael

    1997-11-01

    The damage growth in unidirectional composite materials is a complex evolutionary process. The initiation, growth and interaction of these damage mechanisms are strongly influenced by the properties of the constituent materials. In addition, thermal residual stresses are usually induced in composite material during the curing process. Therefore it is essential to consider the effect of the properties of the constituent materials and thermal residual stresses on the fracture behavior of composite materials. In this study, a computational methodology that employs a hybrid micromechanical-anisotropic continuum model developed previously to simulate the damage growth on the constituent level of composite materials has been modified and extended to include the effect of temperature change. The unique features of this methodology is that multiple modes of damage can be simulated simultaneously, and the direction of damage growth, in the form of a crack path, needs not be pre-selected. More specifically, the methodology uses a special purpose finite element program, PSEUDO, with a node splitting and nodal force relaxation algorithm that is capable of generating new crack surfaces to simulate damage initiation and growth in unidirectional fiber reinforced composites. An incremental elastic-plastic algorithm with Jsb2 flow theory and isotropic hardening is incorporated to account for matrix plastic deformation when analyzing damage growth in metal matrix composites. Damage progression in two types of metal matrix composites, namely, the as-received boron/aluminum-5.6/6061-AR and the solution aged and treated boron/aluminum-5.6/6061-T6 metal matrix composites, with thermal residual stresses, have been analyzed. The results show that the thermal residual stresses do have significant effects on the damage initiation, damage progression and the notch strengths of the composite materials.

  4. Forest Residues Bundling Project

    Treesearch

    U.S. Forest Service

    2007-01-01

    During the summer of 2003, the U.S. Forest Service conducted an evaluation of biomass bundling for forest residue extraction. This CD provides a report of the project results, a video documentary project record, and a collection of images from the project. Additional information is available at:

  5. [China's crop residues resources evaluation].

    PubMed

    Xie, Guanghui; Wang, Xiaoyu; Ren, Lantian

    2010-07-01

    The availability of crop residues in China is reviewed in this article. The definition of crop residues is clarified as the total byproducts of field production and processing industry thereafter, and methodology for evaluating crop residues is discussed. Based on literature, the progress on the crop residue assessment is addressed. The annual field crops residues in China from 1991 to 1999 were estimated between 6.0-6.8 hundred million tons, while the data for the process residues were not available. From 2000 to 2007, the annual crop residues were estimated between 5.9-7.3 hundred million tons, while the processing residues at the range of 0.9-1.1 hundred million tons. The reasons for the significant variations are due to the disagreement on crop residue definition, different, even inaccurate residue to grain ratio data used in the estimations, and the lacking of clear understanding on the statistical analysis and grain outputs related to the crop residue evaluation. With the complete statistic analysis method, the author's group evaluated the residues in 2006 and 2007 to be 7.4 hundred million tones in total, including 6.5 hundred million tons for field crop residues and 0.9 hundred million tons for process residues. Moreover, the geographic distribution of the field crop residues was analyzed based on the harvest indices (HI) tested within the near five years.

  6. Photoexcited riboflavin induces oxidative damage to human serum albumin

    NASA Astrophysics Data System (ADS)

    Hirakawa, Kazutaka; Yoshioka, Takuto

    2015-08-01

    Photoexcited riboflavin induced damage of human serum albumin (HSA), a water soluble protein, resulting in the diminishment of fluorescence from the tryptophan residue. Because riboflavin hardly photosensitized singlet oxygen generation and sodium azide, a singlet oxygen quencher, did not inhibit protein damage, electron transfer-mediated oxidation of HSA was speculated. Fluorescence lifetime of riboflavin was not affected by HSA, suggesting that the excited triplet state of riboflavin is responsible for protein damage through electron transfer. In addition, the preventive effect of xanthone derivatives, triplet quenchers, on photosensitized protein damage could be evaluated using this photosensitized reaction system of riboflavin and HSA.

  7. Delamination, durability and damage tolerance of laminated composite materials

    NASA Technical Reports Server (NTRS)

    O'Brien, T. K.

    1991-01-01

    Research exploring the role of delamination on the durability and damage tolerance of advanced composite materials is reviewed. Recent studies on the characterization of composite delamination are summarized. Recent analytical solutions for interlaminar stresses and strain energy release rates associated with common sources of delamination are also reviewed. The role of delamination in low velocity impact, residual compression strength, and in fatigue is highlighted. Delamination is shown to be the common damage mode observed in all of these problems. A Damage Threshold/Fail-safety concept for addressing composite damage tolerance is discussed.

  8. Surrogate Modeling of High-Fidelity Fracture Simulations for Real-Time Residual Strength Predictions

    NASA Technical Reports Server (NTRS)

    Spear, Ashley D.; Priest, Amanda R.; Veilleux, Michael G.; Ingraffea, Anthony R.; Hochhalter, Jacob D.

    2011-01-01

    A surrogate model methodology is described for predicting, during flight, the residual strength of aircraft structures that sustain discrete-source damage. Starting with design of experiment, an artificial neural network is developed that takes as input discrete-source damage parameters and outputs a prediction of the structural residual strength. Target residual strength values used to train the artificial neural network are derived from 3D finite element-based fracture simulations. Two ductile fracture simulations are presented to show that crack growth and residual strength are determined more accurately in discrete-source damage cases by using an elastic-plastic fracture framework rather than a linear-elastic fracture mechanics-based method. Improving accuracy of the residual strength training data does, in turn, improve accuracy of the surrogate model. When combined, the surrogate model methodology and high fidelity fracture simulation framework provide useful tools for adaptive flight technology.

  9. The ASCE Residuals Transport Manual

    SciTech Connect

    Albertson, O.E.; Bizier, P.A.; Brown, J.; Koch, C.; Sadick, T.

    1999-07-01

    This presentation will highlight the ASCE Residuals Transport Manual, which has been published by ASCE this year. This document, which represents the state of the art in information on residuals transport, is designed to be used by both the active practitioner, as well as for instructional purposes. The authors will present the various chapters which cover the following topics: Conveyance of Water and Wastewater Residuals, Rheology, Sludge Characteristics, Quality and Quantity, Overview of Residuals Conveyance Devices, Pumping of Viscous Sludges and Slurries, Transport of Thickened Residuals, Conveyance of Dewatered Residuals, Transport of Granular and Compactable Residuals, and Case Studies. The Objective of the Transport Monograph is to summarize in one concise volume the general state of knowledge regarding residuals transport from both water and wastewater residuals. The presentation will cover each chapter and will review the pertinent information contained in the manual.

  10. Dynamic Rupture Simulations with Plastic Yielding in Fault Damage Zone

    NASA Astrophysics Data System (ADS)

    Day, S. M.; Roten, D.; Olsen, K. B.; Cui, Y.

    2016-12-01

    Observations of fault-zone trapped waves indicate that faults are surrounded by damage zones with reduced seismic velocities. We investigate how plastic effects around the fault, enhanced by the reduced strength of pre-fractured rocks inside the low-velocity zone (LVZ), affect ground motions at various distances from the fault. 3-D dynamic rupture simulations are performed with the AWP-ODC finite difference code, using a slip-weakening fault friction law, a Drucker-Prager (DP) yield criterion and depth-dependent stress. We simulate M 7.5 earthquakes with a LVZ embedded in a horizontally layered model, as well as M 7.7 earthquakes on the southern San Andreas fault with a LVZ added to the 3D heterogeneous mesh (SCEC CVM 3c). Within a 500 m wide and 4 km deep inner fault zone, we assume a 30% reduction in shear-wave velocity with respect to wallrock, and a reduced Geological Strength Index (GSI) of 30, 50 or 75, representative of a fractured rock mass of poor, moderate and good quality, respectively. The Hoek-Brown criterion is then used to derive equivalent friction angles and cohesions, consistent with these GSI values, for the DP criterion. In the linear case, the presence of a LVZ increases mean near-surface peak slip rates by 50%, from 2 to 3 m/s. These amplifications are compensated by fault zone plasticity in poor and moderate quality rock masses, where near-surface peak slip rates average to 0.5 m/s and 1.5 m/s, respectively; no significant reduction is obtained in good quality (almost unfractured) fault zones. Trapping of seismic waves inside the LVZ results in reduced peak ground velocities (PGVs) outside of the fault zone even in the linear case; these reductions are more pronounced if plasticity is taken into account. Plasticity acts by truncating frequency-distribution curves of PGVs obtained near the fault. In the horizontally layered medium, the highest PGVs are reduced from 2.6 m/s to 2.2 for moderate, and to 1.7 m/s for poor quality fault zones. In

  11. New damage-sensitive feature for structures with bolted joints

    NASA Astrophysics Data System (ADS)

    Luo, W. F.; Yu, L.

    2017-05-01

    Compared with riveted and welded joints, bolted joints have advantages of easily dismantled, high load carrying and load-transferring capacity. However, bolted joints are also weaker components of assembled structures. Structural damage detection (SDD) on bolted joints is much required in the field of structural health monitoring (SHM). A new SDD method is proposed for damage identification of structures with bolted joints based on residual error of AR model in time series analysis. Firstly, a new data standardization process is defined to maintain the information of damage location. Then, a new structural damage feature sensitive to structural damage is developed based on the standard deviation of AR model residual errors. To verify the proposed method, a bolted joint structure is designed and fabricated in laboratory, connection damages of structures are simulated by loosening the bolted joints. The acceleration responses of structures with bolted joints under healthy and damage cases are acquired. Finally, the SDD is performed by traditional DSF and the new DSF. The illustrated results show that the proposed method is a hybrid tool for the bolted joint damage detection with the new damage-sensitive feature. In addition, some related issues will be discussed as well.

  12. Size Effects in Impact Damage of Composite Sandwich Panels

    NASA Technical Reports Server (NTRS)

    Dobyns, Alan; Jackson, Wade

    2003-01-01

    Panel size has a large effect on the impact response and resultant damage level of honeycomb sandwich panels. It has been observed during impact testing that panels of the same design but different panel sizes will show large differences in damage when impacted with the same impact energy. To study this effect, a test program was conducted with instrumented impact testing of three different sizes of sandwich panels to obtain data on panel response and residual damage. In concert with the test program. a closed form analysis method was developed that incorporates the effects of damage on the impact response. This analysis method will predict both the impact response and the residual damage of a simply-supported sandwich panel impacted at any position on the panel. The damage is incorporated by the use of an experimental load-indentation curve obtained for the face-sheet/honeycomb and indentor combination under study. This curve inherently includes the damage response and can be obtained quasi-statically from a rigidly-backed specimen or a specimen with any support conditions. Good correlation has been obtained between the test data and the analysis results for the maximum force and residual indentation. The predictions can be improved by using a dynamic indentation curve. Analyses have also been done using the MSC/DYTRAN finite element code.

  13. Residual stresses in material processing

    SciTech Connect

    Kozaczek, K.J.; Watkins, T.R.; Hubbard, C.R.; Wang, Xun-Li; Spooner, S.

    1994-09-01

    Material manufacturing processes often introduce residual stresses into the product. The residual stresses affect the properties of the material and often are detrimental. Therefore, the distribution and magnitude of residual stresses in the final product are usually an important factor in manufacturing process optimization or component life prediction. The present paper briefly discusses the causes of residual stresses. It then adresses the direct, nondestructive methods of residual stress measurement by X-ray and neutron diffraction. Examples are presented to demonstrate the importance of residual stress measurement in machining and joining operations.

  14. A Coupled Approach for Structural Damage Detection with Incomplete Measurements

    NASA Technical Reports Server (NTRS)

    James, George; Cao, Timothy; Kaouk, Mo; Zimmerman, David

    2013-01-01

    This historical work couples model order reduction, damage detection, dynamic residual/mode shape expansion, and damage extent estimation to overcome the incomplete measurements problem by using an appropriate undamaged structural model. A contribution of this work is the development of a process to estimate the full dynamic residuals using the columns of a spring connectivity matrix obtained by disassembling the structural stiffness matrix. Another contribution is the extension of an eigenvector filtering procedure to produce full-order mode shapes that more closely match the measured active partition of the mode shapes using a set of modified Ritz vectors. The full dynamic residuals and full mode shapes are used as inputs to the minimum rank perturbation theory to provide an estimate of damage location and extent. The issues associated with this process are also discussed as drivers of near-term development activities to understand and improve this approach.

  15. Prediction of residual shear strength of corroded reinforced concrete beams

    NASA Astrophysics Data System (ADS)

    Imam, Ashhad; Azad, Abul Kalam

    2016-09-01

    With the aim of providing experimental data on the shear capacity and behavior of corroded reinforced concrete beams that may help in the development of strength prediction models, the test results of 13 corroded and four un-corroded beams are presented. Corrosion damage was induced by accelerated corrosion induction through impressed current. Test results show that loss of shear strength of beams is mostly attributable to two important damage factors namely, the reduction in stirrups area due to corrosion and the corrosion-induced cracking of concrete cover to stirrups. Based on the test data, a method is proposed to predict the residual shear strength of corroded reinforced concrete beams in which residual shear strength is calculated first by using corrosion-reduced steel area alone, and then it is reduced by a proposed reduction factor, which collectively represents all other applicable corrosion damage factors. The method seems to yield results that are in reasonable agreement with the available test data.

  16. Residual Neuromuscular Blockade.

    PubMed

    Plummer-Roberts, Anna L; Trost, Christina; Collins, Shawn; Hewer, Ian

    2016-02-01

    This article provides an update on residual neuromuscular blockade for nurse anesthetists. The neuromuscular junction, pharmacology for producing and reversing neuromuscular blockade, monitoring sites and methods, and patient implications relating to incomplete reversal of neuromuscular blockade are reviewed. Overall recommendations include using multiple settings when employing a peripheral nerve stimulator for monitoring return of neuromuscular function and administering pharmacologic reversal when the train-of-four ratio is below 0.9.

  17. Examination of Residuals

    DTIC Science & Technology

    1961-01-01

    observations have been made to test a prediction of the theory. Another example would be an experiment on extrasensory perception ; most people believe that...to have the same n and v and yet differ perceptibly in the properties of their residuals. This will be illustrated by two examples with very small n...logarithmically. In recording sensory perceptions or value judgments arbitrary numerical scores are sometimes used, and on the face of it these might as well be

  18. SRC Residual fuel oils

    DOEpatents

    Tewari, Krishna C.; Foster, Edward P.

    1985-01-01

    Coal solids (SRC) and distillate oils are combined to afford single-phase blends of residual oils which have utility as fuel oils substitutes. The components are combined on the basis of their respective polarities, that is, on the basis of their heteroatom content, to assure complete solubilization of SRC. The resulting composition is a fuel oil blend which retains its stability and homogeneity over the long term.

  19. First superheavy element experiments at the GSI recoil separator TASCA: The production and decay of element 114 in the {sup 244}Pu({sup 48}Ca,3-4n) reaction

    SciTech Connect

    Gates, J. M.; Duellmann, Ch. E.; Schaedel, M.; Ackermann, D.; Block, M.; Bruechle, W.; Essel, H. G.; Hartmann, W.; Hessberger, F. P.; Huebner, A.; Jaeger, E.; Khuyagbaatar, J.; Kindler, B.; Krier, J.; Kurz, N.; Lommel, B.; Schaffner, H.; Schausten, B.; Schimpf, E.; Steiner, J.

    2011-05-15

    Experiments with the new recoil separator, Transactinide Separator and Chemistry Apparatus (TASCA), at the GSI were performed by using beams of {sup 48}Ca to irradiate targets of {sup 206-208}Pb, which led to the production of {sup 252-254}No isotopes. These studies allowed for evaluation of the performance of TASCA when coupled to a new detector and electronics system. By following these studies, the isotopes of element 114 ({sup 288-291}114) were produced in irradiations of {sup 244}Pu targets with {sup 48}Ca beams at compound nucleus excitation energies around 41.7 and 37.5 MeV, demonstrating TASCA's ability to perform experiments with picobarn-level cross sections. A total of 15 decay chains were observed and were assigned to the decay of {sup 288-291}114. A new {alpha}-decay branch in {sup 281}Ds was observed, leading to the new nucleus {sup 277}Hs.

  20. Widespread fatigue damage monitoring: Issues and concerns

    NASA Technical Reports Server (NTRS)

    Swift, T.

    1994-01-01

    This paper is intended to illustrate the considerable effect that small in-service undetectable multi-site-damage (MSD) can have on the residual strength capability of aging aircraft structures. In general, very few people in the industry believe that tiny cracks of undetectable size are a problem because they know that many aircraft have been able to survive much larger damage. In fact they have been certified for this large damage capability. However, this is not the issue. The real issue is the effect the tiny cracks, at multiple sites, have on the large damage capability which the industry has become accustomed to expect and which the aircraft have been certified to sustain. The concern is that this message does not appear to be fully understood by many people outside the fracture community. The prime purpose of this paper, therefore, has been to convey this message by describing in simple terms the net section yielding phenomenon in ductile materials which causes loss in lead crack residual strength in the presence of MSD. The explanation continues with a number of examples on complex stiffened structures, using the results of previous finite element analyses, which illustrate that the effect of MSD is extremely sensitive to structural configuration. It is hoped that those members of the aviation community who believe that tiny cracks are not a problem will read this paper very carefully.

  1. Damage Pre-Cursors Based Assessment of Accrued Thermo-Mechanical Damage and Remaining Useful Life in Field Deployed Electronics

    NASA Astrophysics Data System (ADS)

    Lall, Pradeep; Harsha, Mahendra; Goebel, Kai; Jones, Jim

    Field deployed electronics may accrue damage due to environmental exposure and usage after finite period of service but may not often have any o-indicators of failure such as cracks or delamination. A method to interrogate the damage state of field deployed electronics in the pre-failure space may allow insight into the damage initiation, progression, and remaining useful life of the deployed system. Aging has been previously shown to effect the reliability and constitutive behavior of second-level leadfree interconnects. Prognostication of accrued damage and assessment of residual life can provide valuable insight into impending failure. In this paper, field deployed parts have been extracted and prognosticated for accrued damage and remaining useful life in an anticipated future deployment environment. A subset of the field deployed parts have been tested to failure in the anticipated field deployed environment to validate the assessment of remaining useful life. In addition, some parts have been subjected to additional known thermo-mechanical stresses and the incremental damage accrued validated with respect to the amount of additional damage imposed on the assemblies. The presented methodology uses leading indicators of failure based on micro-structural evolution of damage to identify accrued damage in electronic systems subjected to sequential stresses of thermal aging and thermal cycling. Damage equivalency methodologies have been developed to map damage accrued in thermal aging to the reduction in thermo-mechanical cyclic life based on damage proxies. The expected error with interrogation of system state and assessment of residual life has been quantified. Prognostic metrics including α-λmetric, sample standard deviation, mean square error, mean absolute percentage error, average bias, relative accuracy, and cumulative relative accuracy have been used to compare the performance of the damage proxies.

  2. ARX model-based damage sensitive features for structural damage localization using output-only measurements

    NASA Astrophysics Data System (ADS)

    Roy, Koushik; Bhattacharya, Bishakh; Ray-Chaudhuri, Samit

    2015-08-01

    The study proposes a set of four ARX model (autoregressive model with exogenous input) based damage sensitive features (DSFs) for structural damage detection and localization using the dynamic responses of structures, where the information regarding the input excitation may not be available. In the proposed framework, one of the output responses of a multi-degree-of-freedom system is assumed as the input and the rest are considered as the output. The features are based on ARX model coefficients, Kolmogorov-Smirnov (KS) test statistical distance, and the model residual error. At first, a mathematical formulation is provided to establish the relation between the change in ARX model coefficients and the normalized stiffness of a structure. KS test parameters are then described to show the sensitivity of statistical distance of ARX model residual error with the damage location. The efficiency of the proposed set of DSFs is evaluated by conducting numerical studies involving a shear building and a steel moment-resisting frame. To simulate the damage scenarios in these structures, stiffness degradation of different elements is considered. It is observed from this study that the proposed set of DSFs is good indicator for damage location even in the presence of damping, multiple damages, noise, and parametric uncertainties. The performance of these DSFs is compared with mode shape curvature-based approach for damage localization. An experimental study has also been conducted on a three-dimensional six-storey steel moment frame to understand the performance of these DSFs under real measurement conditions. It has been observed that the proposed set of DSFs can satisfactorily localize damage in the structure.

  3. Developments in impact damage modeling for laminated composite structures

    NASA Technical Reports Server (NTRS)

    Dost, Ernest F.; Avery, William B.; Swanson, Gary D.; Lin, Kuen Y.

    1991-01-01

    Damage tolerance is the most critical technical issue for composite fuselage structures studied in the Advanced Technology Composite Aircraft Structures (ATCAS) program. The objective here is to understand both the impact damage resistance and residual strength of the laminated composite fuselage structure. An understanding of the different damage mechanisms which occur during an impact event will support the selection of materials and structural configurations used in different fuselage quadrants and guide the development of analysis tools for predicting the residual strength of impacted laminates. Prediction of the damage state along with the knowledge of post-impact response to applied loads will allow for engineered stacking sequencies and structural configurations; intelligent decisions on repair requirements will also result.

  4. Wood Residue Distribution Simulator (WORDS)

    Treesearch

    Douglas A. Eza; James W. McMinn; Peter E. Dress

    1984-01-01

    Successful development of woody biomass for energy will depend on the distribution of local supply and demand within subregions, rather than on the total inventory of residues. The Wood Residue Distribution Simulator (WORDS) attempts to find a least-cost allocation of residues from local sources of supply to local sources of demand, given the cost of the materials,...

  5. Corrosion Damage Functions

    SciTech Connect

    Jones, Russell H.

    2002-11-30

    Corrosion damage can lead to reduced operational lifetimes. Often this damage is not as obvious as general corrosion but takes the form of pits, intergranular corrosion, crevice corrosion and hydrogen absorption. These types of corrosion damage lead to stress corrosion cracking, hydrogen induced cracking and corrosion fatigue. A critical step in defining a corrosion damage function is determining the relationship between the corrosion damage, the resulting crack propagation mechanism and component lifetimes. The sequence of events is often some localized corrosion event such as pitting, transition of the pit to a planar crack, propagation of this short crack, transition of the short crack to long crack conditions and continued propagation through Stage I, II, and III of the long crack SCC regimes. A description of critical corrosion damage processes and examples of the transition to long crack SCC conditions will be discussed.

  6. Damage Tolerance of Composites

    NASA Technical Reports Server (NTRS)

    Hodge, Andy

    2007-01-01

    Fracture control requirements have been developed to address damage tolerance of composites for manned space flight hardware. The requirements provide the framework for critical and noncritical hardware assessment and testing. The need for damage threat assessments, impact damage protection plans, and nondestructive evaluation are also addressed. Hardware intended to be damage tolerant have extensive coupon, sub-element, and full-scale testing requirements in-line with the Building Block Approach concept from the MIL-HDBK-17, Department of Defense Composite Materials Handbook.

  7. Impact damage of composites

    NASA Technical Reports Server (NTRS)

    Wu, Hsi-Young T.; Springer, George S.

    1986-01-01

    A model is described for estimating the impact damage of fiber reinforced composite plates. The displacements and stresses are calculated by a three dimensional transient, finite element method of solution of the governing equations applicable to a linearly elastic body. The region in which damage occurs is estimated using the Tsai-Wu failure criterion. A computer code was developed which can be used to calculate the impact force, displacements and velocities of the plate and the impact body, stresses and strains in the plate, and the damage area. Sample numerical results are presented illustrating the type of information provided by the code. Comparisons between measured and calculated damage areas are also given.

  8. Evaluation of thermal residual stresses in laser drilled alumina ceramics using Micro-Raman spectroscopy and COMSOL Multiphysics

    NASA Astrophysics Data System (ADS)

    Bharatish, A.; Narasimha Murthy, H. N.; Aditya, G.; Anand, B.; Satyanarayana, B. S.; Krishna, M.

    2015-07-01

    This paper presents evaluation of thermal residual stresses in the heat affected zone of laser drilled alumina ceramic by using Micro-Raman spectroscopy. The residual stresses were evaluated for the holes corresponding to the optimal parameters of laser power, scanning speed, frequency and hole diameter. Three such cases were considered for the study. Residual stresses were obtained as a function of the Raman shifts. The nature and magnitude of the residual stresses were indicative of the extent of damage caused in the heat affected zone. In cases where the initial tensile residual stresses exceeded the tensile strength of alumina, cracks were initiated. Laser drilling with higher laser power and lower scanning speed induced initially high compressive and cyclic thermal stresses, causing greater damage to the hole. Transient thermal analysis was performed using COMSOL Multiphysics to predict residual thermal stresses and to validate the micro-Raman results. Scanning Electron Microscopy was used to confirm the damage caused in the heat affected zone.

  9. Protein damage and repair controlling seed vigor and longevity.

    PubMed

    Ogé, Laurent; Broyart, Caroline; Collet, Boris; Godin, Béatrice; Jallet, Denis; Bourdais, Gildas; Job, Dominique; Grappin, Philippe

    2011-01-01

    The formation of abnormal isoaspartyl residues derived from aspartyl or asparaginyl residues is a major source of spontaneous protein misfolding in cells. The repair enzyme protein L: -isoaspartyl methyltransferase (PIMT) counteracts such damage by catalyzing the conversion of abnormal isoaspartyl residues to their normal aspartyl forms. Thus, this enzyme contributes to the survival of many organisms, including plants. Analysis of the accumulation of isoaspartyl-containing proteins and its modulation by the PIMT repair pathway, using germination tests, immunodetection, enzymatic assays, and HPLC analysis, gives new insights in understanding controlling mechanisms of seed longevity and vigor.

  10. Quantification of residual stress from photonic signatures of fused silica

    NASA Astrophysics Data System (ADS)

    Cramer, K. Elliott; Hayward, Maurice; Yost, William T.

    2014-02-01

    A commercially available grey-field polariscope (GFP) instrument for photoelastic examination is used to assess impact damage inflicted upon the outer-most pane of Space Shuttle windows made from fused silica. A method and apparatus for calibration of the stress-optic coefficient using four-point bending is discussed. The results are validated on known material (acrylic) and are found to agree with literature values to within 6%. The calibration procedure is then applied to fused-silica specimens and the stress-optic coefficient is determined to be 2.43 ± 0.54 × 10-12 Pa-1. Fused silica specimens containing impacts artificially made at NASA's Hypervelocity Impact Technology Facility (HIT-F), to simulate damage typical during space flight, are examined. The damage sites are cored from fused silica window carcasses and examined with the GFP. The calibrated GFP measurements of residual stress patterns surrounding the damage sites are presented.

  11. Animal damage to birch

    Treesearch

    James S. Jordan; Francis M. Rushmore

    1969-01-01

    A relatively few animal species are responsible for most of the reported damage to the birches. White-tailed deer, yellow-bellied sapsuckers, porcupines, moose, and hares are the major animals involved. We will review reports of damage, discuss the underlying causes, and describe possible methods of control. For example, heavy deer browsing that eliminates birch...

  12. Radiation damage annealing kinetics

    NASA Technical Reports Server (NTRS)

    Dresselhaus, M. S.

    1971-01-01

    Various spectral response studies are reported that assess lithium doping effects on the recovery process of electron damaged silicon solar cells. Measurements of both the minority carrier lifetimes and the energy level spectrum of the defects are used to predict lifetime damage constants and carrier removal rates relevant to the operation of the solar lithium-doped cell and its annealing kinetics.

  13. Animal damage management handbook.

    Treesearch

    Hugh C. Black

    1994-01-01

    This handbook treats animal damage management (ADM) in the West in relation to forest, range, and recreation resources; predator management is not addressed. It provides a comprehensive reference of safe, effective, and practical methods for managing animal damage on National Forest System lands. Supporting information is included in references after each chapter and...

  14. Damage and intensity survey

    USGS Publications Warehouse

    Reagor, G.; Brewer, L.R.

    1992-01-01

    A field team (the tuhors) from the National Earthquake Information Center (USGS) conducted a damage survey of the epicentral area in the week following the earthquakes. Detailed information about damage and where and how strongly the earthquakes were felt was obtained through interviews with local residents and personal observations. 

  15. Squirrel Damage to Pines

    Treesearch

    USDA Forest Service

    1981-01-01

    Flagging (dead branch tips) on jack pine and red pine may be caused by insects, diseases, or mechanical damage. In the Lake States, flagging is often the result of mechanical damage, sometimes girdling, caused when the cones are torn off by red squirrels.

  16. Nonlinear damage analysis: Postulate and evaluation

    NASA Technical Reports Server (NTRS)

    Leis, B. N.; Forte, T. P.

    1983-01-01

    The objective of this program is to assess the viability of a damage postulate which asserts that the fatigue resistance curve of a metal is history dependent due to inelastic action. The study focusses on OFE copper because this simple model material accentuates the inelastic action central to the damage postulate. Data relevant to damage evolution and crack initiation are developed via a study of surface topography. The effects of surface layer residual stresses are explored via comparative testing as were the effects in initial prestraining. The results of the study very clearly show the deformation history dependence of the fatigue resistance of OFE copper. Furthermore the concept of deformation history dependence is shown to qualitatively explain the fatigue resistance of all histories considered. Likewise quantitative predictions for block cycle histories are found to accurately track the observed results. In this respect the assertion that damage per cycle for a given level of the damage parameter is deformation history dependent appears to be physically justified.

  17. Residual strength of thin panels with cracks

    NASA Technical Reports Server (NTRS)

    Madenci, Erdogan

    1994-01-01

    The previous design philosophies involving safe life, fail-safe and damage tolerance concepts become inadequate for assuring the safety of aging aircraft structures. For example, the failure mechanism for the Aloha Airline accident involved the coalescence of undetected small cracks at the rivet holes causing a section of the fuselage to peel open during flight. Therefore, the fuselage structure should be designed to have sufficient residual strength under worst case crack configurations and in-flight load conditions. Residual strength is interpreted as the maximum load carrying capacity prior to unstable crack growth. Internal pressure and bending moment constitute the two major components of the external loads on the fuselage section during flight. Although the stiffeners in the form of stringers, frames and tear straps sustain part of the external loads, the significant portion of the load is taken up by the skin. In the presence of a large crack in the skin, the crack lips bulge out with considerable yielding; thus, the geometric and material nonlinearities must be included in the analysis for predicting residual strength. Also, these nonlinearities do not permit the decoupling of in-plane and out-of-plane bending deformations. The failure criterion combining the concepts of absorbed specific energy and strain energy density addresses the aforementioned concerns. The critical absorbed specific energy (local toughness) for the material is determined from the global specimen response and deformation geometry based on the uniaxial tensile test data and detailed finite element modeling of the specimen response. The use of the local toughness and stress-strain response at the continuum level eliminates the size effect. With this critical parameter and stress-strain response, the finite element analysis of the component by using STAGS along with the application of this failure criterion provides the stable crack growth calculations for residual strength predictions.

  18. Residual strength of thin panels with cracks

    NASA Astrophysics Data System (ADS)

    Madenci, Erdogan

    1994-12-01

    The previous design philosophies involving safe life, fail-safe and damage tolerance concepts become inadequate for assuring the safety of aging aircraft structures. For example, the failure mechanism for the Aloha Airline accident involved the coalescence of undetected small cracks at the rivet holes causing a section of the fuselage to peel open during flight. Therefore, the fuselage structure should be designed to have sufficient residual strength under worst case crack configurations and in-flight load conditions. Residual strength is interpreted as the maximum load carrying capacity prior to unstable crack growth. Internal pressure and bending moment constitute the two major components of the external loads on the fuselage section during flight. Although the stiffeners in the form of stringers, frames and tear straps sustain part of the external loads, the significant portion of the load is taken up by the skin. In the presence of a large crack in the skin, the crack lips bulge out with considerable yielding; thus, the geometric and material nonlinearities must be included in the analysis for predicting residual strength. Also, these nonlinearities do not permit the decoupling of in-plane and out-of-plane bending deformations. The failure criterion combining the concepts of absorbed specific energy and strain energy density addresses the aforementioned concerns. The critical absorbed specific energy (local toughness) for the material is determined from the global specimen response and deformation geometry based on the uniaxial tensile test data and detailed finite element modeling of the specimen response. The use of the local toughness and stress-strain response at the continuum level eliminates the size effect. With this critical parameter and stress-strain response, the finite element analysis of the component by using STAGS along with the application of this failure criterion provides the stable crack growth calculations for residual strength predictions.

  19. A damage mechanics based approach to structural deterioration and reliability

    SciTech Connect

    Bhattcharya, B.; Ellingwood, B.

    1998-02-01

    Structural deterioration often occurs without perceptible manifestation. Continuum damage mechanics defines structural damage in terms of the material microstructure, and relates the damage variable to the macroscopic strength or stiffness of the structure. This enables one to predict the state of damage prior to the initiation of a macroscopic flaw, and allows one to estimate residual strength/service life of an existing structure. The accumulation of damage is a dissipative process that is governed by the laws of thermodynamics. Partial differential equations for damage growth in terms of the Helmholtz free energy are derived from fundamental thermodynamical conditions. Closed-form solutions to the equations are obtained under uniaxial loading for ductile deformation damage as a function of plastic strain, for creep damage as a function of time, and for fatigue damage as function of number of cycles. The proposed damage growth model is extended into the stochastic domain by considering fluctuations in the free energy, and closed-form solutions of the resulting stochastic differential equation are obtained in each of the three cases mentioned above. A reliability analysis of a ring-stiffened cylindrical steel shell subjected to corrosion, accidental pressure, and temperature is performed.

  20. Residual gas analyzer calibration

    NASA Technical Reports Server (NTRS)

    Lilienkamp, R. H.

    1972-01-01

    A technique which employs known gas mixtures to calibrate the residual gas analyzer (RGA) is described. The mass spectra from the RGA are recorded for each gas mixture. This mass spectra data and the mixture composition data each form a matrix. From the two matrices the calibration matrix may be computed. The matrix mathematics requires the number of calibration gas mixtures be equal to or greater than the number of gases included in the calibration. This technique was evaluated using a mathematical model of an RGA to generate the mass spectra. This model included shot noise errors in the mass spectra. Errors in the gas concentrations were also included in the valuation. The effects of these errors was studied by varying their magnitudes and comparing the resulting calibrations. Several methods of evaluating an actual calibration are presented. The effects of the number of gases in then, the composition of the calibration mixture, and the number of mixtures used are discussed.

  1. Metabolic Damage and Metabolic Damage Control in Plants

    SciTech Connect

    Hanson, Andrew D.; Henry, Christopher S.; Fiehn, Oliver; Crecy-Lagard, Valerie de

    2016-01-01

    It is increasingly clear that (a) many metabolites undergo spontaneous or enzyme-catalyzed side reactions in vivo, (b) the damaged metabolites formed by these reactions can be harmful, and (c) organisms have biochemical systems that limit the buildup of damaged metabolites. These damage-control systems either return a damaged molecule to its pristine state (metabolite repair) or convert harmful molecules to harmless ones (damage preemption). Because all organisms share a core set of metabolites that suffer the same chemical and enzymatic damage reactions, certain damage-control systems are widely conserved across the kingdoms of life. Relatively few damage reactions and damage-control systems are well known. Uncovering new damage reactions and identifying the corresponding damaged metabolites, damage-control genes, and enzymes demands a coordinated mix of chemistry, metabolomics, cheminformatics, biochemistry, and comparative genomics. This review illustrates the above points using examples from plants, which are at least as prone to metabolite damage as other organisms.

  2. Numerical prediction of the low-velocity impact damage and compression after impact strength of composite laminates

    NASA Astrophysics Data System (ADS)

    Tan, Wei; Falzon, Brian G.; Chiu, Louis N. S.; Price, Mark

    2015-02-01

    Low-velocity impact damage can drastically reduce the residual mechanical properties of the composite structure even when there is barely visible impact damage. The ability to computationally predict the extent of damage and compression after impact (CAI) strength of a composite structure can potentially lead to the exploration of a larger design space without incurring significant development time and cost penalties. A three-dimensional damage model, to predict both low-velocity impact damage and compression after impact CAI strength of composite laminates, has been developed and implemented as a user material subroutine in the commercial finite element package, ABAQUS/Explicit. The virtual tests were executed in two steps, one to capture the impact damage and the other to predict the CAI strength. The observed intra-laminar damage features, delamination damage area as well as residual strength are discussed. It is shown that the predicted results for impact damage and CAI strength correlated well with experimental testing.

  3. Thermopower of doped and damaged NbSe 3

    NASA Astrophysics Data System (ADS)

    Chaikin, P. M.; Fuller, W. W.; Lacoe, R.; Kwak, J. F.; Greene, R. L.; Eckert, J. C.; Ong, N. P.

    1981-07-01

    We have measured the thermoelectric power of pure NbSe 3 as well as samples which have been substitutionally doped with isoelectronic Ta and the charged impurity Ti and separate samples which have been radiation damaged by 2.5 MeV protons. We find that 5% Ta doping supresses the lower temperature charge density wave transition. In contrast, the radiation damaged samples and 0.1% Ti samples with larger residual resistivities then the Ta doped samples retain the CDW transitions. A discussion is given of the difference between doping and radiation damage.

  4. Fracture and damage; Winter Annual Meeting of the American Society of Mechanical Engineers, Anaheim, CA, Nov. 8-13, 1992

    NASA Technical Reports Server (NTRS)

    Nagar, Arvind (Editor)

    1992-01-01

    The latest developments in the area of fracture and damage at high temperatures are discussed, in particular: modeling; analysis and experimental techniques for interface damage in composites including the effects of residual stresses and temperatures; and crack growth, inelastic deformation and fracture parameters for isotropic materials. Also included are damage modeling and experiments at elevated temperatures.

  5. Fracture and damage; Winter Annual Meeting of the American Society of Mechanical Engineers, Anaheim, CA, Nov. 8-13, 1992

    NASA Technical Reports Server (NTRS)

    Nagar, Arvind (Editor)

    1992-01-01

    The latest developments in the area of fracture and damage at high temperatures are discussed, in particular: modeling; analysis and experimental techniques for interface damage in composites including the effects of residual stresses and temperatures; and crack growth, inelastic deformation and fracture parameters for isotropic materials. Also included are damage modeling and experiments at elevated temperatures.

  6. Residual stress near cracks of K and fused silica under 1064 nm nanosecond laser irradiation

    NASA Astrophysics Data System (ADS)

    Zhang, Zhen; Liu, Hongjie; Huang, Jin; Zhou, Xiaoyan; Ren, Dahua; Cheng, Xinlu; Jiang, Xiaodong; Wu, Weidong; Zheng, Wanguo

    2012-11-01

    Measurements of birefringence induced in K9 and fused silica specimens by cracks produced by 1064 nm Nd∶YAG laser have been presented. The Birefringence data is converted into the units of stress, thus permitting the estimation of residual stress near crack. The intensity of residual stress in K9 glass is larger than that in fused silica under the same condition. The similarity of residual stress distribution along the y-axis reveals that the nature of shock wave transmission in optical materials under 1064 nm laser irradiation is the same with each other. The value of residual stress can be influenced by laser parameters and characterization of optical material. Simulation based on a theoretical model giving the residual stress field around a crack is developed for comparison with experiment results. The probability of initial damage and the direction of the energy dissipation in cracks determine the residual stress distribution. The thermal stress coupling enlarges the asymmetry of residual stress distribution. Residual stress in optical material has a strong effect on fracture and should be taken into account in any formulation that involves the enhanced damage resistance of optical components used in laser induced damage experiments.

  7. Experimental determination of residual stress

    NASA Technical Reports Server (NTRS)

    Ferguson, Milton W.

    1991-01-01

    Residual stresses in finished parts have often been regarded as factors contributing to premature part failure and geometric distortions. Currently, residual stresses in welded structures and railroad components are being investigated. High residual stresses formed in welded structures due primarily to the differential contractions of the weld material as it cools and solidifies can have a profound effect on the surface performance of the structure. In railroad wheels, repeated use of the brakes causes high residual stresses in the rims which may lead to wheel failure and possible derailment. The goals of the study were: (1) to develop strategies for using x-ray diffraction to measure residual stress; (2) to subject samples of Inconel 718 to various mechanical and heat treatments and to measure the resulting stress using x-ray diffraction; and (3) to measure residual stresses in ferromagnetic alloys using magnetoacoustics.

  8. Materials recovery from shredder residues

    SciTech Connect

    Daniels, E. J.; Jody, B. J.; Pomykala, J., Jr.

    2000-07-24

    Each year, about five (5) million ton of shredder residues are landfilled in the US. Similar quantities are landfilled in Europe and the Pacific Rim. Landfilling of these residues results in a cost to the existing recycling industry and also represents a loss of material resources that are otherwise recyclable. In this paper, the authors outline the resources recoverable from typical shredder residues and describe technology that they have developed to recover these resources.

  9. War Damage Assessment

    NASA Technical Reports Server (NTRS)

    1994-01-01

    During and after the Persian Gulf war, hundreds of "oil lakes" were created in Kuwait by oil released from damaged wells. The lakes are a hazard to the Kuwait atmosphere, soil and ground water and must be carefully monitored. Boston University Center for Remote Sensing, assisted by other organizations, has accurately mapped the lakes using Landsat and Spot imagery. The war damage included the formation of over 300 oil lakes, oil pollution and sand dune movement. Total damage area is over 5,400 square kilometers - 30 percent of Kuwait's total surface area.

  10. Microwave emission and crop residues

    NASA Technical Reports Server (NTRS)

    Jackson, Thomas J.; O'Neill, Peggy E.

    1991-01-01

    A series of controlled experiments were conducted to determine the significance of crop residues or stubble in estimating the emission of the underlying soil. Observations using truck-mounted L and C band passive microwave radiometers showed that for dry wheat and soybeans the dry residue caused negligible attenuation of the background emission. Green residues, with water contents typical of standing crops, did have a significant effect on the background emission. Results for these green residues also indicated that extremes in plant structure, as created using parallel and perpendicular stalk orientations, can cause very large differences in the degree of attenuation.

  11. Microwave emission and crop residues

    NASA Technical Reports Server (NTRS)

    Jackson, Thomas J.; O'Neill, Peggy E.

    1991-01-01

    A series of controlled experiments were conducted to determine the significance of crop residues or stubble in estimating the emission of the underlying soil. Observations using truck-mounted L and C band passive microwave radiometers showed that for dry wheat and soybeans the dry residue caused negligible attenuation of the background emission. Green residues, with water contents typical of standing crops, did have a significant effect on the background emission. Results for these green residues also indicated that extremes in plant structure, as created using parallel and perpendicular stalk orientations, can cause very large differences in the degree of attenuation.

  12. DNA damage, EROD activity, condition indices, and their linkages with contaminants in female flounder (Platichthys flesus) from the southern Baltic Sea.

    PubMed

    Dabrowska, Henryka; Kopko, Orest; Góra, Agnieszka; Waszak, Ilona; Walkusz-Miotk, Jolanta

    2014-10-15

    The Baltic Sea is considered as one of the marine areas most exposed to human impacts. A variety of chemical contaminants pose a threat to the habitants. Female flounder (Platichthys flesus) collected from three locations in the southern Baltic Sea in February 2010 were examined for biomarkers of exposure to genotoxic agents (DNA damage), AhR-active contaminants (ethoxyresorufin-O-deethylase, EROD activity), and somatic condition indexes. Organochlorine contaminants (OCs) and polycyclic aromatic hydrocarbon (PAH) metabolites were also measured in individual flounder to evaluate the biological responses in the context of contaminant burden. The genotoxicity, mildly exceeding a background level, revealed a significant relationship with mono-ortho substituted PCB (m-oPCB). Hepatic EROD activity was highly induced, yet showed no association with any of the contaminants measured other than biliary 1-OH pyrene normalized to pigment absorbance. Significant negative relationships were observed for lipid-based OCs and the gonado-somatic index (GSI) as well as for Ʃm-oPCB concentrations and the condition factor (CF). Principal component analysis (PCA) revealed an overall connection between somatic condition indexes, biomarkers, and chemical variables. Of the three locations, flounder inhabiting the Gulf of Gdańsk had the greatest contaminant burden and appeared to be the most affected. Of great concern is the reduced GSI in this location which can be attributed to the effects of contaminants and warrants further investigation. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Diabetes and nerve damage

    MedlinePlus

    Diabetic neuropathy; Diabetes - neuropathy; Diabetes - peripheral neuropathy ... In people with diabetes, the body's nerves can be damaged by decreased blood flow and a high blood sugar level. This condition is ...

  14. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    Damaged power lines are seen during an aerial survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  15. LSD and Genetic Damage

    ERIC Educational Resources Information Center

    Dishotsky, Norman I.; And Others

    1971-01-01

    Reviews studies of the effects of lysergic acid diethylamide (LSD) on man and other organisms. Concludes that pure LSD injected in moderate doses does not cause chromosome or detectable genetic damage and is not a teratogen or carcinogen. (JM)

  16. Court Disallows Damage Claims

    ERIC Educational Resources Information Center

    Tomson, Bernard; Coplan, Norman

    1976-01-01

    In rejecting claims for damages, the Court finds that contract's "increase or decrease of cost" language is not applicable to added overhead costs and loss of labor efficiency resulting from delays over which the contractor has no control. (Author)

  17. LSD and Genetic Damage

    ERIC Educational Resources Information Center

    Dishotsky, Norman I.; And Others

    1971-01-01

    Reviews studies of the effects of lysergic acid diethylamide (LSD) on man and other organisms. Concludes that pure LSD injected in moderate doses does not cause chromosome or detectable genetic damage and is not a teratogen or carcinogen. (JM)

  18. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    Damage to a facility roof is seen during an aerial survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  19. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    Damage to a facility roof is seen during an aerial survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed

  20. Composites Damage Tolerance Workshop

    NASA Technical Reports Server (NTRS)

    Gregg, Wayne

    2006-01-01

    The Composite Damage Tolerance Workshop included participants from NASA, academia, and private industry. The objectives of the workshop were to begin dialogue in order to establish a working group within the Agency, create awareness of damage tolerance requirements for Constellation, and discuss potential composite hardware for the Crew Launch Vehicle (CLV) Upper Stage (US) and Crew Module. It was proposed that a composites damage tolerance working group be created that acts within the framework of the existing NASA Fracture Control Methodology Panel. The working group charter would be to identify damage tolerance gaps and obstacles for implementation of composite structures into manned space flight systems and to develop strategies and recommendations to overcome these obstacles.

  1. Mechanisms of freezing damage.

    PubMed

    Pegg, D E

    1987-01-01

    Freezing of aqueous systems involves numerous simultaneous changes but this review concentrates on direct effects of the formation of ice and the consequent concentration of solutes in the remaining liquid phase. It is generally believed that cell injury at low cooling rates is principally due to the concentration of both intracellular and extracellular electrolytes and that cryoprotectants act by reducing this build-up. New experimental data are presented to support this explanation; we find that the extent of damage to human red blood cells during freezing in solutions of sodium chloride/glycerol/water can be quantitatively accounted for by the increase in solute concentration. However, we also show that a given degree of damage occurs at lower concentrations of solute in the presence of higher concentrations of glycerol; it appears that glycerol contributes an element of damage itself. Recently published studies from Mazur's laboratory have suggested that the dominant damaging factor at low cooling rates is actually the reduction of the quantity of unfrozen water rather than the corresponding increase in salt concentration that accompanies freezing. These data are re-evaluated, and it is argued that the experimental results could equally well be explained by a susceptibility of cells to shrinkage and re-expansion as the concentration of external impermeant solutes first increases during freezing and then decreases during thawing. It is concluded that external ice probably has no directly damaging effect upon dilute suspensions of cells. However, it is also argued that ice is directly damaging whenever it forms intracellularly, and also when it forms extracellularly in densely packed cell suspensions. In the latter case the damage is probably due to recrystallization of the ice masses during thawing. Extracellular ice also has a directly damaging effect when tissues and organs are frozen. The difficulties of designing experimental methods that will yield

  2. Damage Detection Equipment

    NASA Image and Video Library

    2017-01-11

    The prototype Flexible Damage Detection System stands in a laboratory at NASA's Kennedy Space Center in Florida. The system uses circuits printed on thin thermal film and specialized software. The system is designed to show where damage to a surface occurs and how severe it may be. It could offer astronauts a real-time update on their spacecraft's condition during a mission without requiring a spacewalk.

  3. Damage Detection Equipment

    NASA Image and Video Library

    2017-03-10

    Martha Williams, who leads the team inventing the Flexible Damage Detection System, stands in a laboratory with a prototype at NASA's Kennedy Space Center in Florida. The system uses circuits printed on thin thermal film and specialized software. The system is designed to show where damage to a surface occurs and how severe it may be. It could offer astronauts a real-time update on their spacecraft's condition during a mission without requiring a spacewalk.

  4. Damage Detection Equipment

    NASA Image and Video Library

    2017-03-10

    Jamie Szafran, from left, Mark Lewis and Curtis Ihlefeld work with the prototype of the Flexible Damage Detection System in a laboratory with a prototype at NASA's Kennedy Space Center in Florida. The system uses circuits printed on thin thermal film and specialized software. The system is designed to show where damage to a surface occurs and how severe it may be. It could offer astronauts a real-time update on their spacecraft's condition during a mission without requiring a spacewalk.

  5. Damage Detection Equipment

    NASA Image and Video Library

    2017-03-10

    Curtis Ihlefeld, left, and Mark Lewis work with the prototype of the Flexible Damage Detection System in a laboratory with a prototype at NASA's Kennedy Space Center in Florida. The system uses circuits printed on thin thermal film and specialized software. The system is designed to show where damage to a surface occurs and how severe it may be. It could offer astronauts a real-time update on their spacecraft's condition during a mission without requiring a spacewalk.

  6. Damage Detection Equipment

    NASA Image and Video Library

    2017-01-11

    The complete prototype Flexible Damage Detection System stands in a laboratory at NASA's Kennedy Space Center in Florida. The system uses circuits printed on thin thermal film and specialized software. The system is designed to show where damage to a surface occurs and how severe it may be. It could offer astronauts a real-time update on their spacecraft's condition during a mission without requiring a spacewalk. Photo credit: NASA/Dimitri Gerondidakis

  7. Kinetic Damage from Meteorites

    NASA Technical Reports Server (NTRS)

    Cooke, William; Brown, Peter; Matney, Mark

    2017-01-01

    A Near Earth object impacting into Earth's atmosphere may produce damaging effects at the surface due to airblast, thermal pulse, or kinetic impact in the form of meteorites. At large sizes (greater than many tens of meters), the damage is amplified by the hypersonic impact of these large projectiles moving with cosmic velocity, leaving explosively produced craters. However, much more common is simple "kinetic" damage caused by the impact of smaller meteorites moving at terminal speeds. As of this date a handful of instances are definitively known of people or structures being directly hit and/or damaged by the kinetic impact of meteorites. Meteorites known to have struck humans include the Sylacauga, Alabama fall (1954) and the Mbale meteorite fall (1992). Much more common is kinetic meteorite damage to cars, buildings, and even a post box (Claxton, Georgia - 1984). Historical accounts indicate that direct kinetic damage by meteorites may be more common than recent accounts suggest (Yau et al., 1994). In this talk we will examine the contemporary meteorite flux and estimate the frequency of kinetic damage to various structures, as well as how the meteorite flux might affect the rate of human casualties. This will update an earlier study by Halliday et al (1985), adding variations expected in meteorite flux with latitude (Le Feuvre and Wieczorek, 2008) and validating these model predictions of speed and entry angle with observations from the NASA and SOMN fireball networks. In particular, we explore the physical characteristics of bright meteors which may be used as a diagnostic for estimating which fireballs produce meteorites and hence how early warning of such kinetic damage may be estimated in advance through observations and modeling.

  8. Kinetic Damage from Meteorites

    NASA Technical Reports Server (NTRS)

    Cooke, William; Brown, Peter; Matney, Mark

    2017-01-01

    A Near Earth object impacting into Earth's atmosphere may produce damaging effects at the surface due to airblast, thermal pulse, or kinetic impact in the form of meteorites. At large sizes (>many tens of meters), the damage is amplified by the hypersonic impact of these large projectiles moving with cosmic velocity, leaving explosively produced craters. However, much more common is simple "kinetic" damage caused by the impact of smaller meteorites moving at terminal speeds. As of this date a handful of instances are definitively known of people or structures being directly hit and/or damaged by the kinetic impact of meteorites. Meteorites known to have struck humans include the Sylacauga, Alabama fall (1954) and the Mbale meteorite fall (1992). Much more common is kinetic meteorite damage to cars, buildings, and even a post box (Claxton, Georgia - 1984). Historical accounts indicate that direct kinetic damage by meteorites may be more common than recent accounts suggest (Yau et al., 1994). In this talk we will examine the contemporary meteorite flux and estimate the frequency of kinetic damage to various structures, as well as how the meteorite flux might affect the rate of human casualties. This will update an earlier study by Halliday et al (1985), adding variations expected in meteorite flux with latitude (Le Feuvre and Wieczorek, 2008) and validating these model predictions of speed and entry angle with observations from the NASA and SOMN fireball networks. In particular, we explore the physical characteristics of bright meteors which may be used as a diagnostic for estimating which fireballs produce meteorites and hence how early warning of such kinetic damage may be estimated in advance through observations and modelling.

  9. RNF111-dependent neddylation activates DNA damage-induced ubiquitination

    PubMed Central

    Ma, Teng; Chen, Yibin; Zhang, Feng; Yang, Chao-Yie; Wang, Shaomeng; Yu, Xiaochun

    2013-01-01

    Summary Ubiquitin-like proteins have been shown to be covalently conjugated to targets. However, the functions of these ubiquitin-like proteins are largely unknown. Here, we have screened most known ubiquitin-like proteins after DNA damage and found that NEDD8 is involved in the DNA damage response. Following various DNA damage stimuli, NEDD8 accumulated at DNA damage sites, and this accumulation was dependent on an E2 enzyme UBE2M and an E3 ubiquitin ligase RNF111. We further found that histone H4 was polyneddylated in response to DNA damage, and NEDD8 was conjugated to the N-terminal lysine residues of H4. Interestingly, the DNA damage-induced polyneddylation chain could be recognized by the MIU (Motif Interacting with Ubiquitin) domain of RNF168. Loss of DNA damage-induced neddylation negatively regulated DNA damage-induced foci formation of RNF168 and its downstream functional partners, such as 53BP1 and BRCA1, thus affecting the normal DNA damage repair process. PMID:23394999

  10. On tide-induced lagrangian residual current and residual transport: 1. Lagrangian residual current

    USGS Publications Warehouse

    Feng, Shizuo; Cheng, Ralph T.; Pangen, Xi

    1986-01-01

    Residual currents in tidal estuaries and coastal embayments have been recognized as fundamental factors which affect the long-term transport processes. It has been pointed out by previous studies that it is more relevant to use a Lagrangian mean velocity than an Eulerian mean velocity to determine the movements of water masses. Under weakly nonlinear approximation, the parameter k, which is the ratio of the net displacement of a labeled water mass in one tidal cycle to the tidal excursion, is assumed to be small. Solutions for tides, tidal current, and residual current have been considered for two-dimensional, barotropic estuaries and coastal seas. Particular attention has been paid to the distinction between the Lagrangian and Eulerian residual currents. When k is small, the first-order Lagrangian residual is shown to be the sum of the Eulerian residual current and the Stokes drift. The Lagrangian residual drift velocity or the second-order Lagrangian residual current has been shown to be dependent on the phase of tidal current. The Lagrangian drift velocity is induced by nonlinear interactions between tides, tidal currents, and the first-order residual currents, and it takes the form of an ellipse on a hodograph plane. Several examples are given to further demonstrate the unique properties of the Lagrangian residual current.

  11. Taking inventory of woody residuals

    Treesearch

    David McKeever

    2003-01-01

    USDA Forest Service analysis finds 104 million tons of woody residuals available for recovery in the U.S., with wood in MSW and C&D debris streams comprising 28 million tons. The U.S. Department of Agriculture Forest Service conducts a variety of analyses to estimate the quantity of woody residuals in the United States. Its Forest Products Laboratory in Madison,...

  12. Residue-based scattering factors.

    PubMed

    Xu, Hongliang

    2016-11-01

    A glob is defined as a group of atoms in the crystal which can be chosen in various ways. Globs themselves can be used as scattering elements in the theory of structure determination, just as atoms are used at present. In this paper, amino-acid residues are chosen to form globs and empirical formulas for residue-based scattering factors have been developed.

  13. Flexure with damage

    NASA Astrophysics Data System (ADS)

    Manaker, David M.; Turcotte, Donald L.; Kellogg, Louise H.

    2006-09-01

    Ductile behaviour in rocks is often associated with plasticity due to dislocation motion or diffusion under high pressures and temperatures. However, ductile behaviour can also occur in brittle materials. An example would be cataclastic flow associated with folding at shallow crustal levels. Engineers utilize damage mechanics to model the continuum deformation of brittle materials. In this paper we utilize a modified form of damage mechanics that includes a yield stress. Here, damage represents a reduction in frictional strength. We use this empirical approach to simulate bending of the lithosphere through the problem of plate flexure. We use numerical simulations to obtain quasi-static solutions to the Navier equations of elasticity. We use the program GeoFEST v. 4.5 (Geophysical Finite Element Simulation Tool), developed by NASA Jet Propulsion Laboratory, to generate solutions for each time step. When the von Mises stress exceeds the critical stress on an element we apply damage to reduce the shear modulus of the element. Damage is calculated at each time step by a power-law relationship of the ratio of the critical stress to the von Mises stress and the critical strain to the von Mises strain. This results in the relaxation of the material due to increasing damage. To test our method, we apply our damage rheology to a semi-infinite plate deforming under its own weight. Where the von Mises stress exceeds the critical stress, we simulate the formation of damage and observe the time-dependent relaxation of the stress and strain to near the yield strength. We simulate a wide range of behaviours from slow relaxation to instantaneous failure, over timescales that span six orders of magnitude. Using this method, stress relaxation produces perfectly plastic behaviour in cases where failure does not occur. For cases of failure, we observe a rapid increase in damage, analogous to the acceleration of microcrack formation and acoustic emissions prior to failure. Thus

  14. Impact damage in filament wound composite bottles

    NASA Technical Reports Server (NTRS)

    Highsmith, Alton L.

    1993-01-01

    Increasingly, composite materials are being used in advanced structural applications because of the significant weight savings they offer when compared to more traditional engineering materials. The higher cost of composites must be offset by the increased performance that results from reduced structural weight if these new materials are to be used effectively. At present, there is considerable interest in fabricating solid rocket motor cases out of composite materials, and capitalizing on the reduced structural weight to increase rocket performance. However, one of the difficulties that arises when composite materials are used is that composites can develop significant amounts of internal damage during low velocity impacts. Such low velocity impacts may be encountered in routine handling of a structural component like a rocket motor case. The ability to assess the reduction in structural integrity of composite motor cases that experience accidental impacts is essential if composite rocket motor cases are to be certified for manned flight. While experimental studies of the post-impact performance of filament wound composite motor cases haven been proven performed (2,3), scaling impact data from small specimens to full scale structures has proven difficult. If such a scaling methodology is to be achieved, an increased understanding of the damage processes which influence residual strength is required. The study described herein was part of an ongoing investigation of damage development and reduction of tensile strength in filament wound composites subjected to low velocity impacts. The present study, which focused on documenting the damage that develops in filament wound composites as a result of such impacts, included two distinct tasks. The first task was to experimentally assess impact damage in small, filament wound pressure bottles using x-ray radiography. The second task was to study the feasibility of using digital image processing techniques to assist in

  15. 43 CFR 11.84 - Damage determination phase-implementation guidance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... the damage assessment. (2) Natural resource damages are the residual to be determined by incorporating... estimates of natural recovery rates as well as recovery rates that reflect management actions or resource... actions or resource acquisitions, including a “No Action-Natural Recovery” alternative. After the...

  16. Tree damage resulting from thinning in young-growth Douglas-fir and western hemlock.

    Treesearch

    Norman P. Worthington

    1961-01-01

    Thinning trials on three cooperative experimental forests in western Washington have provided an excellent opportunity to evaluate tree damage resulting from typical thinning operations in young-growth timber. The type and degree of damage can, of course, be expected to strongly affect condition and vigor of the residual stand and ultimate success of a thinning regime...

  17. Residual strains in conduit arteries.

    PubMed

    Rachev, A; Greenwald, S E

    2003-05-01

    Residual strains and stresses are those that exist in a body when all external loads are removed. Residual strains in arteries can be characterized by the opening angle of the sector-like cross-section which arises when an unloaded ring segment is radially cut. A review of experimental methods for measuring residual strains and the main results about the variation of the opening angle with arterial localization, age, smooth muscle activity, mechanical environment and certain vascular pathologies are presented and discussed. It is shown that, in addition to their well-established ability to homogenize the stress field in the arterial wall, residual strains make arteries more compliant and thereby improve their performance as elastic reservoirs and ensure more effective local control of the arterial lumen by smooth muscle cells. Finally, evidence that, in some cases, residual strains remain in arteries even after they have been cut radially is discussed.

  18. Determination of acrinathrin residues in honey and beeswax.

    PubMed

    Túri, M S; Mátray, E S

    1999-01-01

    The Asian bee mite (Varroa jacobsoni Oud.) causes variable damage in Hungarian apiaries due to the different and changing conditions. Plastic and wooden strips impregnated with synthetic pyrethroid-type active ingredients show a high efficacy against the mites. These treatments, however, may leave residues in bee products (honey, propolis, wax). After experimental treatment with Gabon PA 92, the levels of active ingredient (acrinathrin) residues were determined in honey and beeswax samples. The analytical results proved that the average concentration of acrinathrin residues was less than 0.01 mg/kg in honey and less than 0.10 mg/kg in beeswax. From the food-hygienic point of view it is favourable that the honey did not become 'contaminated' with acrinathrin during the experimental treatment. The analytical results serve as a basis for the registration of this veterinary product in Hungary.

  19. Assessing Tropical Cyclone Damage

    NASA Astrophysics Data System (ADS)

    Done, J.; Czajkowski, J.

    2012-12-01

    Landfalling tropical cyclones impact large coastal and inland areas causing direct damage due to winds, storm-surge flooding, tornadoes, and precipitation; as well as causing substantial indirect damage such as electrical outages and business interruption. The likely climate change impact of increased tropical cyclone intensity, combined with increases in exposure, bring the possibility of increased damage in the future. A considerable amount of research has focused on modeling economic damage due to tropical cyclones, and a series of indices have been developed to assess damages under climate change. We highlight a number of ways this research can be improved through a series of case study analyses. First, historical loss estimates are revisited to properly account for; time, impacted regions, the source of damage by type, and whether the damage was direct/indirect and insured/uninsured. Second, the drivers of loss from both the socio-economic and physical side are examined. A case is made to move beyond the use of maximum wind speed to more stable metrics and the use of other characteristics of the wind field such as direction, degree of gustiness, and duration is explored. A novel approach presented here is the potential to model losses directly as a function of climate variables such as sea surface temperature, greenhouse gases, and aerosols. This work is the first stage in the development of a tropical cyclone loss model to enable projections of losses under scenarios of both socio-economic change (such as population migration or altered policy) and physical change (such as shifts in tropical cyclone activity one from basin to another or within the same basin).

  20. Surface state reconstruction in ion-damaged SmB6

    DOE PAGES

    Wakeham, N.; Wang, Y. Q.; Fisk, Z.; ...

    2015-02-12

    We have used ion-irradiation to damage the (001) surfaces of SmB₆ single crystals to varying depths, and have measured the resistivity as a function of temperature for each depth of damage. We observe a reduction in the residual resistivity with increasing depth of damage. Our data are consistent with a model in which the surface state is not destroyed by the ion-irradiation, however instead the damaged layer is poorly conducting and the initial surface state is reconstructed below the damage. This behavior is consistent with a surface state that is topologically protected.

  1. Bioinformatic prediction and in vivo validation of residue-residue interactions in human proteins

    NASA Astrophysics Data System (ADS)

    Jordan, Daniel; Davis, Erica; Katsanis, Nicholas; Sunyaev, Shamil

    2014-03-01

    Identifying residue-residue interactions in protein molecules is important for understanding both protein structure and function in the context of evolutionary dynamics and medical genetics. Such interactions can be difficult to predict using existing empirical or physical potentials, especially when residues are far from each other in sequence space. Using a multiple sequence alignment of 46 diverse vertebrate species we explore the space of allowed sequences for orthologous protein families. Amino acid changes that are known to damage protein function allow us to identify specific changes that are likely to have interacting partners. We fit the parameters of the continuous-time Markov process used in the alignment to conclude that these interactions are primarily pairwise, rather than higher order. Candidates for sites under pairwise epistasis are predicted, which can then be tested by experiment. We report the results of an initial round of in vivo experiments in a zebrafish model that verify the presence of multiple pairwise interactions predicted by our model. These experimentally validated interactions are novel, distant in sequence, and are not readily explained by known biochemical or biophysical features.

  2. A new approach for the influence of residual stress on fatigue crack propagation

    NASA Astrophysics Data System (ADS)

    Zhu, Lin; Jia, Min-Ping

    Many manufacturing processes can induce residual stresses in produced components. These residual stresses influence the mean stress during cyclic loading. The initial residual stresses induced during manufacturing change during fatigue damage. This paper presents a research on the change of residual stress distribution during fatigue crack propagation; the research predicts crack propagation by considering residual stress. An analysis approach for the change in residual stress distribution is established according to the diffusion theory of cavity, which is also used to investigate cracks with different orientations. Experiments are conducted to verify the prediction results of residual stress. A probability density function based on Weibull distribution is established to evaluate the accuracy of predicted residual stress. The influence of residual stress on fatigue crack propagation is considered the effective stress intensity factor range, which is calculated under the combined stress field of applied stress and residual stress. An analysis model of crack propagation is established. Furthermore, the model of crack propagation is used to estimate the velocity of crack propagation for the cases, same as the cases of residual stress prediction. The case studies show that the results are basically identical with the experimental results, indicating that the proposed approach is acceptable.

  3. Reducing Radiation Damage

    SciTech Connect

    Blankenbecler, Richard

    2006-06-05

    This talk describes the use of a modified treatment sequence, i.e., radiation dose, geometry, dwell time, etc., to mitigate some of the deleterious effects of cancer radiotherapy by utilizing natural cell repair processes. If bad side effects can be reduced, a more aggressive therapy can be put into place. Cells contain many mechanisms that repair damage of various types. If the damage can not be repaired, cells will undergo apoptosis (cell death). Data will be reviewed that support the fact that a small dose of radiation will activate damage repair genes within a cell. Once the mechanisms are fully active, they will efficiently repair the severe damage from a much larger radiation dose. The data ranges from experiments on specific cell cultures using microarray (gene chip) techniques to experiments on complete organisms. The suggested effect and treatment is consistent with the assumption that all radiation is harmful, no matter how small the dose. Nevertheless, the harm can be reduced. These mechanisms need to be further studied and characterized. In particular, their time dependence needs to be understood before the proposed treatment can be optimized. Under certain situations it is also possible that the deleterious effects of chemotherapy can be mitigated and the damage to radiation workers can be reduced.

  4. Damage characterization of carbon/epoxy laminates using compression-after-impact (CAI) and ultrasonic NDE

    NASA Astrophysics Data System (ADS)

    Subramanian, A.; Dayal, V.; Barnard, D. J.

    2013-01-01

    A study of impact damage morphology in unidirectional carbon/epoxy laminates was performed. A "load drop" method was investigated for prediction of the delamination threshold energy (EDT) for impact. The impacted samples were subjected to uniaxial, in-plane compression to observe the growth of damage, failure modes, and residual strength. Samples were scanned before and after CAI using air-coupled through-transmission ultrasound and amplitude C-scans were collected for visual inspection of damage.

  5. Investigation of low velocity impact damage on filamentary composite materials

    NASA Technical Reports Server (NTRS)

    Bower, Mark V.

    1987-01-01

    Presented are the results of an investigation of the effect of low velocity impact on the residual modulus and residual strength of flat filamentary composite materials. Theoretical analysis of composite materials indicates that the modulus of the material must decrease as impact damage increases. This decrease must also correlate to the decrease in residual strength. This study attempts to verify these hypotheses. Graphite/epoxy laminates (AS4/3501-6) of various fiber orientations (8 (0 deg), 2 (+ or - 45 deg)sub 8) were impacted using a falling weight impact tester. Impact energies ranged from 0.42 to 1.55 ft-lb, with impact velocities from 2.03 to 3.98 ft/sec. The results show that there is a reduction in residual modulus of the plate as the impact energy increases.

  6. Quantification of Residual Stress from Photonic Signatures of Fused Silica

    NASA Technical Reports Server (NTRS)

    Cramer, K. Elliott; Hayward, Maurice; Yost, William E.

    2013-01-01

    A commercially available grey-field polariscope (GFP) instrument for photoelastic examination is used to assess impact damage inflicted upon the outer-most pane of Space Shuttle windows made from fused silica. A method and apparatus for calibration of the stress-optic coefficient using four-point bending is discussed. The results are validated on known material (acrylic) and are found to agree with literature values to within 6%. The calibration procedure is then applied to fused-silica specimens and the stress-optic coefficient is determined to be 2.43 +/- 0.54 x 10(exp -12)/Pa. Fused silica specimens containing impacts artificially made at NASA's Hypervelocity Impact Technology Facility (HIT-F), to simulate damage typical during space flight, are examined. The damage sites are cored from fused silica window carcasses and examined with the GFP. The calibrated GFP measurements of residual stress patterns surrounding the damage sites are presented. Keywords: Glass, fused silica, photoelasticity, residual stress

  7. Prediction of residual tensile strength of transversely impacted composite laminates

    NASA Technical Reports Server (NTRS)

    Lal, K. M.

    1982-01-01

    The response to low velocity impact of graphite-epoxy T300/5208 composite laminates is discussed. Steel balls of 3/8 inch, 5/8 inch, and 1 inch diameter were the projectiles. Impact energy was limited to 1.2 joules. Impacted specimens were ultrasonically C scanned to determine the impact damaged region. The threshold value of impact energy for impact damage was found to be approximately 0.3 joules. A model was developed to predict the tensile residual strength of impact damaged specimens from fracture mechanics concepts. Impacted specimens were tested in tension to provide a fracture data base. The experimental results agreed well with the predictions from fracture mechanics. In this study, the maximum impact velocity used to simulate the low velocity transverse impact from common objects like tool drops was 10 m/s.

  8. Damage Tolerance Assessment Branch

    NASA Technical Reports Server (NTRS)

    Walker, James L.

    2013-01-01

    The Damage Tolerance Assessment Branch evaluates the ability of a structure to perform reliably throughout its service life in the presence of a defect, crack, or other form of damage. Such assessment is fundamental to the use of structural materials and requires an integral blend of materials engineering, fracture testing and analysis, and nondestructive evaluation. The vision of the Branch is to increase the safety of manned space flight by improving the fracture control and the associated nondestructive evaluation processes through development and application of standards, guidelines, advanced test and analytical methods. The Branch also strives to assist and solve non-aerospace related NDE and damage tolerance problems, providing consultation, prototyping and inspection services.

  9. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    A tree is seen across a road during a survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  10. Hurricane Matthew Damage Assessment

    NASA Image and Video Library

    2016-10-08

    An aerial survey of NASA's Kennedy Space Center in Florida was conducted after Hurricane Matthew hit the Space Coast area. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  11. Crumpling Damaged Graphene

    PubMed Central

    Giordanelli, I.; Mendoza, M.; Andrade Jr., J. S.; Gomes, M. A. F.; Herrmann, H. J.

    2016-01-01

    Through molecular mechanics we find that non-covalent interactions modify the fractality of crumpled damaged graphene. Pristine graphene membranes are damaged by adding random vacancies and carbon-hydrogen bonds. Crumpled membranes exhibit a fractal dimension of 2.71 ± 0.02 when all interactions between carbon atoms are considered, and 2.30 ± 0.05 when non-covalent interactions are suppressed. The transition between these two values, obtained by switching on/off the non-covalent interactions of equilibrium configurations, is shown to be reversible and independent on thermalisation. In order to explain this transition, we propose a theoretical model that is compatible with our numerical findings. Finally, we also compare damaged graphene membranes with other crumpled structures, as for instance polymerised membranes and paper sheets, that share similar scaling properties. PMID:27173442

  12. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    The Vehicle Assembly Building is seen during an aerial survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  13. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    Launch Complex 39B is seen during an aerial survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed

  14. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    A support building is seen during an aerial survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  15. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    The Beach House is seen during an aerial survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  16. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    The NASA TV Support Building at the NASA News Center is seen during an aerial survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  17. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    The Kennedy Space Center Visitor Complex is seen during an aerial survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  18. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    The roof of the Operations Support Building II is seen during an aerial survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  19. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    The Launch Complex 39 area is seen during an aerial survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  20. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    Bob Cabana, director of NASA's Kennedy Space Center in Florida, begins an aerial survey of the center on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  1. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    A beach area is seen during a survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  2. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    The NASA News Center is seen during an aerial survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed

  3. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    A display area in front of the Vehicle Assembly Building is seen during an aerial survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  4. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    The Beach House is seen during an aerial survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed

  5. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    The roof of the Operations Support Building I is seen during an aerial survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  6. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    The Central Campus construction site is seen during an aerial survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed

  7. Hurricane Matthew Damage Survey

    NASA Image and Video Library

    2016-10-08

    Launch Complex 39B is seen during an aerial survey of NASA's Kennedy Space Center in Florida on Saturday. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Matthew as the storm passed to the east of Kennedy on Oct. 6 and 7, 2016. Officials determined that the center received some isolated roof damage, damaged support buildings, a few downed power lines, and limited water intrusion. Beach erosion also occurred, although the storm surge was less than expected. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  8. RESIDUAL RISK ASSESSMENT: MAGNETIC TAPE ...

    EPA Pesticide Factsheets

    This document describes the residual risk assessment for the Magnetic Tape Manufacturing source category. For stationary sources, section 112 (f) of the Clean Air Act requires EPA to assess risks to human health and the environment following implementation of technology-based control standards. If these technology-based control standards do not provide an ample margin of safety, then EPA is required to promulgate addtional standards. This document describes the methodology and results of the residual risk assessment performed for the Magnetic Tape Manufacturing source category. The results of this analyiss will assist EPA in determining whether a residual risk rule for this source category is appropriate.

  9. Electromagnetic zonal flow residual responses

    NASA Astrophysics Data System (ADS)

    Catto, Peter J.; Parra, Felix I.; Pusztai, István

    2017-08-01

    The collisionless axisymmetric zonal flow residual calculation for a tokamak plasma is generalized to include electromagnetic perturbations. We formulate and solve the complete initial value zonal flow problem by retaining the fully self-consistent axisymmetric spatial perturbations in the electric and magnetic fields. Simple expressions for the electrostatic, shear and compressional magnetic residual responses are derived that provide a fully electromagnetic test of the zonal flow residual in gyrokinetic codes. Unlike the electrostatic potential, the parallel vector potential and the parallel magnetic field perturbations need not relax to flux functions for all possible initial conditions.

  10. RESIDUAL RISK ASSESSMENT: INDUSTRIAL PROCESS ...

    EPA Pesticide Factsheets

    This document describes the residual risk assessment for the Industrial Process Cooling Towers source category. For stationary sources, section 112 (f) of the Clean Air Act requires EPA to assess risks to human health and the environment following implementation of technology-based control standards. If these technology-based control standards do not provide an ample margin of safety, then EPA is required to promulgate addtional standards. This document describes the methodology and results of the residual risk assessment performed for the Industrial Process Cooling Towers source category. The results of this analyiss will assist EPA in determining whether a residual risk rule for this source category is appropriate.

  11. RESIDUAL RISK ASSESSMENT: ETHYLENE OXIDE ...

    EPA Pesticide Factsheets

    This document describes the residual risk assessment for the Ethylene Oxide Commercial Sterilization source category. For stationary sources, section 112 (f) of the Clean Air Act requires EPA to assess risks to human health and the environment following implementation of technology-based control standards. If these technology-based control standards do not provide an ample margin of safety, then EPA is required to promulgate addtional standards. This document describes the methodology and results of the residual risk assessment performed for the Ethylene Oxide Commercial Sterilization source category. The results of this analyiss will assist EPA in determining whether a residual risk rule for this source category is appropriate.

  12. RESIDUAL RISK ASSESSMENT: ETHYLENE OXIDE ...

    EPA Pesticide Factsheets

    This document describes the residual risk assessment for the Ethylene Oxide Commercial Sterilization source category. For stationary sources, section 112 (f) of the Clean Air Act requires EPA to assess risks to human health and the environment following implementation of technology-based control standards. If these technology-based control standards do not provide an ample margin of safety, then EPA is required to promulgate addtional standards. This document describes the methodology and results of the residual risk assessment performed for the Ethylene Oxide Commercial Sterilization source category. The results of this analyiss will assist EPA in determining whether a residual risk rule for this source category is appropriate.

  13. Prediction of cavitation damage on spillway using K-nearest neighbor modeling.

    PubMed

    Fadaei Kermani, E; Barani, G A; Ghaeini-Hessaroeyeh, M

    2015-01-01

    Cavitation is a common and destructive process on spillways that threatens the stability of the structure and causes damage. In this study, based on the nearest neighbor model, a method has been presented to predict cavitation damage on spillways. The model was tested using data from the Shahid Abbaspour dam spillway in Iran. The level of spillway cavitation damage was predicted for eight different flow rates, using the nearest neighbor model. Moreover, based on the cavitation index, five damage levels from no damage to major damage have been determined. Results showed that the present model predicted damage locations and levels close to observed damage during past floods. Finally, the efficiency and precision of the model was quantified by statistical coefficients. Appropriate values of the correlation coefficient, root mean square error, mean absolute error and coefficient of residual mass show the present model is suitable and efficient.

  14. In-situ damage evolution and micro/macro transition for laminated composites

    NASA Astrophysics Data System (ADS)

    Fan, Jinghong; Zhang, Junqian

    In this paper, a theoretical formulation for the development of matrix cracking damage in composite laminates is presented. To describe the constraint effects on any layer k, an in situ damage effective function, Lambda(k)(ij), is introduced. An equivalent constraint model and a micro/macroscopic damage analysis are then developed to express Lambda(k)(ij) explicitly in terms of constraint stiffness and thickness ratio as well as a damage state variable, D(k). The reduction of E, G and nu in the in situ damage state and a constrained damage evolution law incorporating residual curing strain are then derived through Lambda(k)(ij) and d Lambda(k)(ij)/d D(k), respectively. A series of experimental results are correlated and some phenomena, such as the effects of the lamina thickness on damage initiation, damage evolution, and energy dissipation, are predicted and explained.

  15. Spectrometry researches on interaction and sonodynamic damage of riboflavin (RF) to bovine serum albumin (BSA).

    PubMed

    Wang, Zhiqiu; Li, Jushi; Wang, Jun; Zou, Mingming; Wang, Siyu; Li, Ying; Kong, Yumei; Xia, Lixin

    2012-02-15

    In this paper, the riboflavin (RF) was used to study the interaction and sonodynamic damage to bovine serum albumin (BSA) by fluorescence and UV-vis spectroscopy. The results showed that the RF could efficiently bind to BSA in aqueous solution. Under ultrasonic irradiation, the RF could obviously damage the BSA. In addition, synchronous fluorescence spectroscopy revealed that the RF showed more accessible to tryptophan (Trp) residues than to tyrosine (Tyr) residues. Also, it damaged Trp residues more seriously than Tyr residues under ultrasonic irradiation. At last, the generation of reactive oxygen species (ROS) in sonodynamic process was estimated by the method of Oxidation-Extraction Spectrometry (OES). And then, several radical scavengers were used to determine the kind of ROS. It was found that at least the singlet oxygen ((1)O(2)) and hydroxyl radicals (*OH) were generated. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Damage tolerance certification of a fighter horizontal stabilizer

    NASA Astrophysics Data System (ADS)

    Huang, Jia-Yen; Tsai, Ming-Yang; Chen, Jong-Sheng; Ong, Ching-Long

    1995-05-01

    A review of the program for the damage tolerance certification test of a composite horizontal stabilizer (HS) of a fighter is presented. The object of this program is to certify that the fatigue life and damage tolerance strength of a damaged composite horizontal stabilizer meets the design requirements. According to the specification for damage tolerance certification, a test article should be subjected to two design lifetimes of flight-by-flight load spectra simulating the in-service fatigue loading condition for the aircraft. However, considering the effect of environmental change on the composite structure, one additional lifetime test was performed. In addition, to evaluate the possibilities for extending the service life of the structure, one more lifetime test was carried out with the spectrum increased by a factor of 1.4. To assess the feasibility and reliability of repair technology on a composite structure, two damaged areas were repaired after two lifetimes of damage tolerance test. On completion of four lifetimes of the damage tolerance test, the static residual strength was measured to check whether structural strength after repair met the requirements. Stiffness and static strength of the composite HS with and without damage were evaluated and compared.

  17. Low-velocity impact damage in carbon-fiber composites

    SciTech Connect

    Gweon, Seongyun.

    1989-01-01

    The impact response of fiber composites was investigated to determine the effect of repetitive drop weight testing with increasing energy (RDTIE). The initiation and propagation of impact damage were traced by ultrasonic C-Scanning and sectioning through the damaged region. In thermosetting matrix composites, two or three distinct damage stages could be found from changes in stiffness and percent transferred energy. The first stage involved transverse cracking in the upper and/or bottom layers. In the second stage, the damage was through the sample thickness and in the third the damage propagated to the edge of the sample. In thermoplastic matrix composites, the type of damage was not clearly delineated and many different fracture mechanisms (e.g., delamination, fiber breakage, etc.) occurred simultaneously. Changes in stiffness with cumulative energy at which the damage occurred were affected by matrix, fiber, ply stacking sequence and sample geometry. A simple model was developed to predict these effects. The theory and experimental data were compared and showed reasonable agreement. Static three-point bending test was performed in order to compare with the impact test. In the thermosetting matrix materials, the impact tests and static tests showed similar results. However, thermoplastic matrix composites showed different results between impact tests and static tests. The repetitive drop weight test with increasing energy was compared with fatigue impact test at constant energy. Finally, the effect of impact damage on residual tensile modulus was determined.

  18. Laser shock processing induced residual compression: Impact on predicted crack growth threshold performance

    NASA Astrophysics Data System (ADS)

    Shepard, M. J.

    2005-08-01

    Design credit is not currently taken for laser shock processing (LSP) induced compressive residual stresses in damage tolerant design. The inclusion of these and other compressive stresses in design practice has the potential to dramatically increase predicted fatigue crack growth threshold performance and damage tolerant design life. In the current effort, Ti-6Al-4V coupons will be subjected to shot peening, glass bead peening, and high intensity laser shock processing. The in-depth residual stresses due to processing will be analyzed and then input into a linear elastic fracture mechanics analysis code to predict fatigue crack growth threshold performance. This analysis establishes both the utility and feasibility of incorporating LSP-induced compressive residual stresses into damage tolerant design practice.

  19. OECD Maximum Residue Limit Calculator

    EPA Pesticide Factsheets

    With the goal of harmonizing the calculation of maximum residue limits (MRLs) across the Organisation for Economic Cooperation and Development, the OECD has developed an MRL Calculator. View the calculator.

  20. Coping with brain damage

    NASA Technical Reports Server (NTRS)

    Waring, W.

    1974-01-01

    Two neurological disorders, cerebral palsy, and traumatic brain damage as from an accident, are considered. The discussion covers the incidence of disabilities, their characteristics, and what is now being done to deal with them, particularly in reference to areas in which the capabilities of the engineer can be effectively applied.

  1. Courtside: A Damaging Lesson

    ERIC Educational Resources Information Center

    Zirkel, Perry A.

    2004-01-01

    This case presents a costly lesson for teachers and for districts that include a liquidated, or stipulated, damages clause in their teacher employment contracts. Although the court enforced the clause in this case, in this well-reasoned recent decision and in most of the much older, canvassed case law from other jurisdictions, the answer to the…

  2. Modifying Radiation Damage

    PubMed Central

    Kim, Kwanghee; McBride, William H.

    2011-01-01

    Radiation leaves a fairly characteristic footprint in biological materials, but this is rapidly all but obliterated by the canonical biological responses to the radiation damage. The innate immune recognition systems that sense “danger” through direct radiation damage and through associated collateral damage set in motion a chain of events that, in a tissue compromised by radiation, often unwittingly result in oscillating waves of molecular and cellular responses as tissues attempt to heal. Understanding “nature’s whispers” that inform on these processes will lead to novel forms of intervention targeted more precisely towards modifying them in an appropriate and timely fashion so as to improve the healing process and prevent or mitigate the development of acute and late effects of normal tissue radiation damage, whether it be accidental, as a result of a terrorist incident, or of therapeutic treatment of cancer. Here we attempt to discuss some of the non-free radical scavenging mechanisms that modify radiation responses and comment on where we see them within a conceptual framework of an evolving radiation-induced lesion. PMID:20583981

  3. Loss and damage

    NASA Astrophysics Data System (ADS)

    Huq, Saleemul; Roberts, Erin; Fenton, Adrian

    2013-11-01

    Loss and damage is a relative newcomer to the climate change agenda. It has the potential to reinvigorate existing mitigation and adaptation efforts, but this will ultimately require leadership from developed countries and enhanced understanding of several key issues, such as limits to adaptation.

  4. Coping with brain damage

    NASA Technical Reports Server (NTRS)

    Waring, W.

    1974-01-01

    Two neurological disorders, cerebral palsy, and traumatic brain damage as from an accident, are considered. The discussion covers the incidence of disabilities, their characteristics, and what is now being done to deal with them, particularly in reference to areas in which the capabilities of the engineer can be effectively applied.

  5. Courtside: A Damaging Lesson

    ERIC Educational Resources Information Center

    Zirkel, Perry A.

    2004-01-01

    This case presents a costly lesson for teachers and for districts that include a liquidated, or stipulated, damages clause in their teacher employment contracts. Although the court enforced the clause in this case, in this well-reasoned recent decision and in most of the much older, canvassed case law from other jurisdictions, the answer to the…

  6. Americium recovery from reduction residues

    DOEpatents

    Conner, W.V.; Proctor, S.G.

    1973-12-25

    A process for separation and recovery of americium values from container or bomb'' reduction residues comprising dissolving the residues in a suitable acid, adjusting the hydrogen ion concentration to a desired level by adding a base, precipitating the americium as americium oxalate by adding oxalic acid, digesting the solution, separating the precipitate, and thereafter calcining the americium oxalate precipitate to form americium oxide. (Official Gazette)

  7. Residual fatigue life estimation using a nonlinear ultrasound modulation method

    NASA Astrophysics Data System (ADS)

    Piero Malfense Fierro, Gian; Meo, Michele

    2015-02-01

    Predicting the residual fatigue life of a material is not a simple task and requires the development and association of many variables that as standalone tasks can be difficult to determine. This work develops a modulated nonlinear elastic wave spectroscopy method for the evaluation of a metallic components residual fatigue life. An aluminium specimen (AA6082-T6) was tested at predetermined fatigue stages throughout its fatigue life using a dual-frequency ultrasound method. A modulated nonlinear parameter was derived, which described the relationship between the generation of modulated (sideband) responses of a dual frequency signal and the linear response. The sideband generation from the dual frequency (two signal output system) was shown to increase as the residual fatigue life decreased, and as a standalone measurement method it can be used to show an increase in a materials damage. A baseline-free method was developed by linking a theoretical model, obtained by combining the Paris law and the Nazarov-Sutin crack equation, to experimental nonlinear modulation measurements. The results showed good correlation between the derived theoretical model and the modulated nonlinear parameter, allowing for baseline-free material residual fatigue life estimation. Advantages and disadvantages of these methods are discussed, as well as presenting further methods that would lead to increased accuracy of residual fatigue life detection.

  8. Ovalbumin with Glycated Carboxyl Groups Shows Membrane-Damaging Activity

    PubMed Central

    Tang, Ching-Chia; Shi, Yi-Jun; Chen, Ying-Jung; Chang, Long-Sen

    2017-01-01

    The aim of the present study was to investigate whether glycated ovalbumin (OVA) showed novel activity at the lipid-water interface. Mannosylated OVA (Man-OVA) was prepared by modification of the carboxyl groups with p-aminophenyl α-dextro (d)-mannopyranoside. An increase in the number of modified carboxyl groups increased the membrane-damaging activity of Man-OVA on cell membrane-mimicking vesicles, whereas OVA did not induce membrane permeability in the tested phospholipid vesicles. The glycation of carboxyl groups caused a notable change in the gross conformation of OVA. Moreover, owing to their spatial positions, the Trp residues in Man-OVA were more exposed, unlike those in OVA. Fluorescence quenching studies suggested that the Trp residues in Man-OVA were located on the interface binds with the lipid vesicles, and their microenvironment was abundant in positively charged residues. Although OVA and Man-OVA showed a similar binding affinity for lipid vesicles, the lipid-interacting feature of Man-OVA was distinct from that of OVA. Chemical modification studies revealed that Lys and Arg residues, but not Trp residues, played a crucial role in the membrane-damaging activity of Man-OVA. Taken together, our data suggest that glycation of carboxyl groups causes changes in the structural properties and membrane-interacting features of OVA, generating OVA with membrane-perturbing activities at the lipid-water interface. PMID:28264493

  9. Evaluation of residue-residue contact prediction in CASP10

    PubMed Central

    Monastyrskyy, Bohdan; D’Andrea, Daniel; Fidelis, Krzysztof; Tramontano, Anna; Kryshtafovych, Andriy

    2013-01-01

    We present the results of the assessment of the intra-molecular residue-residue contact predictions from 26 prediction groups participating in the 10th round of the CASP experiment. The most recently developed direct coupling analysis methods did not take part in the experiment likely because they require a very deep sequence alignment not available for any of the 114 CASP10 targets. The performance of contact prediction methods was evaluated with the measures used in previous CASPs (i.e., prediction accuracy and the difference between the distribution of the predicted contacts and that of all pairs of residues in the target protein), as well as new measures, such as the Matthews correlation coefficient, the area under the precision-recall curve and the ranks of the first correctly and incorrectly predicted contact. We also evaluated the ability to detect inter-domain contacts and tested whether the difficulty of predicting contacts depends upon the protein length and the depth of the family sequence alignment. The analyses were carried out on the target domains for which structural homologs did not exist or were difficult to identify. The evaluation was performed for all types of contacts (short, medium, and long-range), with emphasis placed on long-range contacts, i.e. those involving residues separated by at least 24 residues along the sequence. The assessment suggests that the best CASP10 contact prediction methods perform at approximately the same level, and comparably to those participating in CASP9. PMID:23760879

  10. DISSOLUTION OF NEPTUNIUM OXIDE RESIDUES

    SciTech Connect

    Kyser, E

    2009-01-12

    This report describes the development of a dissolution flowsheet for neptunium (Np) oxide (NpO{sub 2}) residues (i.e., various NpO{sub 2} sources, HB-Line glovebox sweepings, and Savannah River National Laboratory (SRNL) thermogravimetric analysis samples). Samples of each type of materials proposed for processing were dissolved in a closed laboratory apparatus and the rate and total quantity of off-gas were measured. Samples of the off-gas were also analyzed. The quantity and type of solids remaining (when visible) were determined after post-dissolution filtration of the solution. Recommended conditions for dissolution of the NpO{sub 2} residues are: Solution Matrix and Loading: {approx}50 g Np/L (750 g Np in 15 L of dissolver solution), using 8 M nitric acid (HNO{sub 3}), 0.025 M potassium fluoride (KF) at greater than 100 C for at least 3 hours. Off-gas: Analysis of the off-gas indicated nitric oxide (NO), nitrogen dioxide (NO{sub 2}) and nitrous oxide (N{sub 2}O) as the only identified components. No hydrogen (H{sub 2}) was detected. The molar ratio of off-gas produced per mole of Np dissolved ranged from 0.25 to 0.4 moles of gas per mole of Np dissolved. A peak off-gas rate of {approx}0.1 scfm/kg bulk oxide was observed. Residual Solids: Pure NpO{sub 2} dissolved with little or no residue with the proposed flowsheet but the NpCo and both sweepings samples left visible solid residue after dissolution. For the NpCo and Part II Sweepings samples the residue amounted to {approx}1% of the initial material, but for the Part I Sweepings sample, the residue amounted to {approx}8 % of the initial material. These residues contained primarily aluminum (Al) and silicon (Si) compounds that did not completely dissolve under the flowsheet conditions. The residues from both sweepings samples contained minor amounts of plutonium (Pu) particles. Overall, the undissolved Np and Pu particles in the residues were a very small fraction of the total solids.

  11. Glycosylases utilize ``stop and go'' motion to locate DNA damage

    NASA Astrophysics Data System (ADS)

    Nelson, Shane

    2015-03-01

    Oxidative damage to DNA results in alterations that are mutagenic or even cytotoxic. Base excision repair is a mechanism that functions to identify and correct these lesions, and is present in organisms ranging from bacteria to humans. DNA glycosylases are the first enzymes in this pathway and function to locate and remove oxidatively damaged bases, and do so utilizing only thermal energy. However, the question remains of how these enzymes locate and recognize a damaged base among millions of undamaged bases. Utilizing fluorescence video microscopy with high spatial and temporal resolution, we have observed a number of different fluorescently labeled glycosylases (including bacterial FPG, NEI, and NTH as well as mammalian MutyH and OGG). These enzymes diffuse along DNA tightropes at approximately 0.01 +/- 0.005 μm2/s with binding lifetimes ranging from one second to several minutes. Chemically induced damage to the DNA substrate causes a ~ 50% reduction in diffusion coefficients and a ~ 400% increase in binding lifetimes, while mutation of the key ``wedge residue'' - which has been shown to be responsible for damage detection - results in a 200% increase in the diffusion coefficient. Utilizing a sliding window approach to measure diffusion coefficients within individual trajectories, we observe that distributions of diffusion coefficients are bimodal, consistent with periods of diffusive motion interspersed with immobile periods. Utilizing a unique chemo-mechanical simulation approach, we demonstrate that the motion of these glycosylases can be explained as free diffusion along the helical pitch of the DNA, punctuated with two different types of pauses: 1) rapid, short-lived pauses as the enzyme rapidly probes DNA bases to interrogate for damage and, 2) less frequent, longer lived pauses that reflect the enzyme bound to and catalytically removing a damaged base. These simulations also indicate that the wedge residue is critical for interrogation and recognition of

  12. Residual stresses in welded plates

    NASA Technical Reports Server (NTRS)

    Bernstein, Edward L.

    1994-01-01

    The purpose of this project was to develop a simple model which could be used to study residual stress. The mechanism that results in residual stresses in the welding process starts with the deposition of molten weld metal which heats the immediately adjacent material. After solidification of weld material, normal thermal shrinkage is resisted by the adjacent, cooler material. When the thermal strain exceeds the elastic strain corresponding to the yield point stress, the stress level is limited by this value, which decreases with increasing temperature. Cooling then causes elastic unloading which is restrained by the adjoining material. Permanent plastic strain occurs, and tension is caused in the region immediately adjacent to the weld material. Compression arises in the metal farther from the weld in order to maintain overall static equilibrium. Subsequent repair welds may add to the level of residual stresses. The level of residual stress is related to the onset of fracture during welding. Thus, it is of great importance to be able to predict the level of residual stresses remaining after a weld procedure, and to determine the factors, such as weld speed, temperature, direction, and number of passes, which may affect the magnitude of remaining residual stress. It was hoped to use traditional analytical modeling techniques so that it would be easier to comprehend the effect of these variables on the resulting stress. This approach was chosen in place of finite element methods so as to facilitate the understanding of the physical processes. The accuracy of the results was checked with some existing experimental studies giving residual stress levels found from x-ray diffraction measurements.

  13. Damage tolerance of a composite sandwich with interleaved foam core

    NASA Technical Reports Server (NTRS)

    Ishai, Ori; Hiel, Clement

    1992-01-01

    A composite sandwich panel consisting of carbon fiber-reinforced plastic (CFRP) skins and a syntactic foam core was selected as an appropriate structural concept for the design of wind tunnel compressor blades. Interleaving of the core with tough interlayers was done to prevent core cracking and to improve damage tolerance of the sandwich. Simply supported sandwich beam specimens were subjected to low-velocity drop-weight impacts as well as high velocity ballistic impacts. The performance of the interleaved core sandwich panels was characterized by localized skin damage and minor cracking of the core. Residual compressive strength (RCS) of the skin, which was derived from flexural test, shows the expected trend of decreasing with increasing size of the damage, impact energy, and velocity. In the case of skin damage, RCS values of around 50 percent of the virgin interleaved reference were obtained at the upper impact energy range. Based on the similarity between low-velocity and ballistic-impact effects, it was concluded that impact energy is the main variable controlling damage and residual strength, where as velocity plays a minor role.

  14. Damage tolerance of a composite sandwich with interleaved foam core

    NASA Technical Reports Server (NTRS)

    Ishai, Ori; Hiel, Clement

    1992-01-01

    A composite sandwich panel consisting of carbon fiber-reinforced plastic (CFRP) skins and a syntactic foam core was selected as an appropriate structural concept for the design of wind tunnel compressor blades. Interleaving of the core with tough interlayers was done to prevent core cracking and to improve damage tolerance of the sandwich. Simply supported sandwich beam specimens were subjected to low-velocity drop-weight impacts as well as high velocity ballistic impacts. The performance of the interleaved core sandwich panels was characterized by localized skin damage and minor cracking of the core. Residual compressive strength (RCS) of the skin, which was derived from flexural test, shows the expected trend of decreasing with increasing size of the damage, impact energy, and velocity. In the case of skin damage, RCS values of around 50 percent of the virgin interleaved reference were obtained at the upper impact energy range. Based on the similarity between low-velocity and ballistic-impact effects, it was concluded that impact energy is the main variable controlling damage and residual strength, where as velocity plays a minor role.

  15. Influence of Impactor Mass on the Damage Characteristics and Failure Strength of Laminated Composite Plates

    NASA Technical Reports Server (NTRS)

    Ambur, Damodar R.; Kemmerly, Heather L.

    1998-01-01

    The results of an experimental study of the effect of impactor mass on the low-speed impact response of laminated flat composite plates is presented. Dropped weight impact response, damage characteristics, and residual strengths of quasi-isotropic flat plates are presented for a range of energy levels by systematically varying the mass of the impactor. Measured contact forces and damage areas are also presented. The results indicate that the contact force and damage area are nonlinear functions of the impactor mass and vary considerably over the entire range of energy levels considered. The different damage levels induced in a plate specimen when impacted at a given energy level with impactors of different masses significantly influence its compressive residual strength. The results provide clear and consistent trends in contact force, damage area, and compression-after-impact strength when the data are expressed as a function of the impactor momentum.

  16. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    An aerial survey of NASA's Kennedy Space Center in Florida was conducted on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  17. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    The Multi-Payload Processing Facility (MPPF) is seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  18. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    A trailer flipped on it's side at the Turn Basin is seen during a survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  19. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    Center Director, Robert Cabana, conducts an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  20. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    Kars Park I is seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  1. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    The Blue Origin construction site at Exploration Park is seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  2. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    The shoreline is seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  3. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    Launch Complex 39B is seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  4. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    The Launch Control Center (LCC) is seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  5. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    Launch Complex 39 surrounding areas are seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  6. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    A tank stroage unit near Launch Complex 39 is seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  7. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    The Central Campus construction site and Headquarters building are seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  8. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    The Launch Complex 39 Press Site is seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  9. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    The Kennedy Space Center Visitor Complex is seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  10. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    The Beach House is seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  11. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    A boat dock torn apart is seen during a survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  12. Tornado damage risk assessment

    SciTech Connect

    Reinhold, T.A.; Ellingwood, B.

    1982-09-01

    Several proposed models were evaluated for predicting tornado wind speed probabilities at nuclear plant sites as part of a program to develop statistical data on tornadoes needed for probability-based load combination analysis. A unified model was developed which synthesized the desired aspects of tornado occurrence and damage potential. The sensitivity of wind speed probability estimates to various tornado modeling assumptions are examined, and the probability distributions of tornado wind speed that are needed for load combination studies are presented.

  13. Hydrothermal carbonization of agricultural residues.

    PubMed

    Oliveira, Ivo; Blöhse, Dennis; Ramke, Hans-Günter

    2013-08-01

    The work presented in this article addresses the application of hydrothermal carbonization (HTC) to produce a solid fuel named HTC-Biochar, whose characteristics are comparable to brown coal. Several batch HTC experiments were performed using agricultural residues (AR) as substrates, commonly treated in farm-based biogas plants in Germany. Different AR were used in different combinations with other biomass residues. The biogas potential from the resulting process water was also determined. The combination of different AR lead to the production of different qualities of HTC-Biochars as well as different mass and energy yields. Using more lignocellulosic residues lead to higher mass and energy yields for the HTC-Biochar produced. Whilst residues rich in carbohydrates of lower molecular weight such as corn silage and dough residues lead to the production of a HTC-Biochar of better quality and more similar to brown coal. Process water achieved a maximum of 16.3 L CH4/kg FM (fresh matter).

  14. Earthquake damage to schools

    USGS Publications Warehouse

    McCullough, Heather

    1994-01-01

    These unusual slides show earthquake damage to school and university buildings around the world. They graphically illustrate the potential danger to our schools, and to the welfare of our children, that results from major earthquakes. The slides range from Algeria, where a collapsed school roof is held up only by students' desks; to Anchorage, Alaska, where an elementary school structure has split in half; to California and other areas, where school buildings have sustained damage to walls, roofs, and chimneys. Interestingly, all the United States earthquakes depicted in this set of slides occurred either on a holiday or before or after school hours, except the 1935 tremor in Helena, Montana, which occurred at 11:35 am. It undoubtedly would have caused casualties had the schools not been closed days earlier by Helena city officials because of a damaging foreshock. Students in Algeria, the People's Republic of China, Armenia, and other stricken countries were not so fortunate. This set of slides represents 17 destructive earthquakes that occurred in 9 countries, and covers more than a century--from 1886 to 1988. Two of the tremors, both of which occurred in the United States, were magnitude 8+ on the Richter Scale, and four were magnitude 7-7.9. The events represented by the slides (see table below) claimed more than a quarter of a million lives.

  15. Crack Growth Simulation and Residual Strength Prediction in Airplane Fuselages

    NASA Technical Reports Server (NTRS)

    Chen, Chuin-Shan; Wawrzynek, Paul A.; Ingraffea, Anthony R.

    1999-01-01

    The objectives were to create a capability to simulate curvilinear crack growth and ductile tearing in aircraft fuselages subjected to widespread fatigue damage and to validate with tests. Analysis methodology and software program (FRANC3D/STAGS) developed herein allows engineers to maintain aging aircraft economically, while insuring continuous airworthiness, and to design more damage-tolerant aircraft for the next generation. Simulations of crack growth in fuselages were described. The crack tip opening angle (CTOA) fracture criterion, obtained from laboratory tests, was used to predict fracture behavior of fuselage panel tests. Geometrically nonlinear, elastic-plastic, thin shell finite element crack growth analyses were conducted. Comparisons of stress distributions, multiple stable crack growth history, and residual strength between measured and predicted results were made to assess the validity of the methodology. Incorporation of residual plastic deformations and tear strap failure was essential for accurate residual strength predictions. Issue related to predicting crack trajectory in fuselages were also discussed. A directional criterion, including T-stress and fracture toughness orthotropy, was developed. Curvilinear crack growth was simulated in coupon and fuselage panel tests. Both T-stress and fracture toughness orthotropy were essential to predict the observed crack paths. Flapping of fuselages were predicted. Measured and predicted results agreed reasonable well.

  16. The distribution of subsurface damage in fused silica

    SciTech Connect

    Miller, P E; Suratwala, T I; Wong, L L; Feit, M D; Menapace, J A; Davis, P J; Steele, R A

    2005-11-21

    Managing subsurface damage during the shaping process and removing subsurface damage during the polishing process is essential in the production of low damage density optical components, such as those required for use on high peak power lasers. Removal of subsurface damage, during the polishing process, requires polishing to a depth which is greater than the depth of the residual cracks present following the shaping process. To successfully manage, and ultimately remove subsurface damage, understanding the distribution and character of fractures in the subsurface region introduced during fabrication process is important. We have characterized the depth and morphology of subsurface fractures present following fixed abrasive and loose abrasive grinding processes. At shallow depths lateral cracks and an overlapping series of trailing indentation fractures were found to be present. At greater depths, subsurface damage consists of a series of trailing indentation fractures. The area density of trailing fractures changes as a function of depth, however the length and shape of individual cracks remain nearly constant for a given grinding process. We have developed and applied a model to interpret the depth and crack length distributions of subsurface surface damage in terms of key variables including abrasive size and load.

  17. DAMCAL; Damage Reach Stage-Damage Calculation: Users Manual

    DTIC Science & Technology

    1979-02-01

    M AD-A273 611 US Army Corps of Engineers Hydrologic Engineering Center GENERALIZED COMPUTER PROGRAM DTIC "k ELECTE DEC 13 1993 DAMCAL A Damage Reach...Stage- Damage Calculation User’s Manual February 1979 93-30134 ApprOved for Public Release. Distribution Unlimited. CPD-35 93 12 100 3 8 DAMCAL Damage ...Reach Stage- Damage Calculation Accesion For User’s Manual TIS ’C&I DTIC TA.3 Juhfificatoc.n By ............. .......................... February 1979

  18. Research on the residual stress of glass ceramic based on rotary ultrasonic drilling

    NASA Astrophysics Data System (ADS)

    Sun, Lipeng; Jin, Yuzhu; Chen, Jianhua

    2016-10-01

    In the process of machining, the glass ceramic is easy to crack and damage, etc. And the residual stress in the machined surface may cause the crack to different extent in the later stage. Some may even affect the performance of the product. The residual stress of rotary ultrasonic drilling and mechanical processing is compared in different machining parameters (spindle speed, feed rate). The effects of processing parameters and methods are researched, in order to reduce the residual stress in the mechanical processing of glass ceramic, and provide guidance for the actual processing.

  19. Observation of DNA damage of human hepatoma cells irradiated by heavy ions using comet assay

    PubMed Central

    Qiu, Li-Mei; Li, Wen-Jian; Pang, Xin-Yue; Gao, Qing-Xiang; Feng, Yan; Zhou, Li-Bin; Zhang, Gao-Hua

    2003-01-01

    AIM: Now many countries have developed cancer therapy with heavy ions, especially in GSI (Gesellschaft fürSchwerionenforschung mbH, Darmstadt, Germany), remarkable results have obtained, but due to the complexity of particle track structure, the basic theory still needs further researching. In this paper, the genotoxic effects of heavy ions irradiation on SMMC-7721 cells were measured using the single cell gel electrophoresis (comet assay). The information about the DNA damage made by other radiations such as X-ray, γ-ray, UV and fast neutron irradiation is very plentiful, while little work have been done on the heavy ions so far. Hereby we tried to detect the reaction of liver cancer cells to heavy ion using comet assay, meanwhile to establish a database for clinic therapy of cancer with the heavy ions. METHODS: The human hepatoma cells were chosen as the test cell line irradiated by 80Mev/u 20Ne10+ on HIRFL (China), the radiation-doses were 0, 0.5, 1, 2, 4 and 8 Gy, and then comet assay was used immediately to detect the DNA damages, 100-150 cells per dose-sample (30-50 cells were randomly observed at constant depth of the gel). The tail length and the quantity of the cells with the tail were put down. EXCEL was used for statistical analysis. RESULTS: We obtained clear images by comet assay and found that SMMC-7721 cells were all damaged apparently from the dose 0.5 Gy to 8 Gy (t-test: P < 0.001, vs control). The tail length and tail moment increased as the doses increased, and the number of cells with tails increased with increasing doses. When doses were higher than 2 Gy, nearly 100% cells were damaged. Furthermore, both tail length and tail moment, showed linear equation. CONCLUSION: From the clear comet assay images, our experiment proves comet assay can be used to measure DNA damages by heavy ions. Meanwhile DNA damages have a positive correlation with the dose changes of heavy ions and SMMC-7721 cells have a great radiosensitivity to 20Ne10+. Different

  20. LSD and genetic damage.

    PubMed

    Dishotsky, N I; Loughman, W D; Mogar, R E; Lipscomb, W R

    1971-04-30

    Of nine studies in vitro, six have indicated some degree of induced chromosomal breakage after exposure to LSD; three failed to confirm these results. The damage, when found, was generally of the chromatid type, arising during or after DNA synthesis. This damage, with one exception, was the result of concentrations of drug and durations of exposure which could not be achieved in humans with reasonable dosages. There did not appear to be a dose-response relation. The magnitude of damage, when found, was in the range encompassing the effects of many commonly used substances. The absence in vitro of excretory and detoxifying systems present in vivo, as well as several negative reports, cast doubt on the relevance of in vitro results. In 21 chromosomal studies in vivo, 310 subjects were examined. Of these, 126 were treated with pure LSD; the other 184 were exposed to illicit, "alleged" LSD. A maximum of only 18 of 126 (14.29 percent) of the subjects in the group exposed to pure LSD showed higher frequency of chromosome aberration than the controls. In contrast, a maximum of 90 of 184 (48.91 percent) of the subjects taking illicit LSD showed an increase in frequency of aberrations. Of all the subjects reported to have chromosome damage, only 18 of the 108 (16.67 percent) were exposed to pure LSD. The frequency of individuals with chromosomal damage reported among illicit drug users was more than triple that associated with the use of pharmacologically pure LSD. We conclude that chromosome damage, when found, was related to the effects of drug abuse in general and not, as initially reported, to LSD alone. We believe that pure LSD ingested in moderate dosages does not produce chromosome damage detectable by available methods. No significant work on carcinogenic potential of LSD has been reported so far. No cause-and-effect relation and no increase in the incidence of neoplasia among LSD users have been demonstrated. Case reports (three in 4.0 years) of leukemia and other

  1. Dry fermentation of agricultural residues

    NASA Astrophysics Data System (ADS)

    Jewell, W. J.; Chandler, J. A.; Dellorto, S.; Fanfoni, K. J.; Fast, S.; Jackson, D.; Kabrick, R. M.

    1981-09-01

    A dry fermentation process is discussed which converts agricultural residues to methane, using the residues in their as produced state. The process appears to simplify and enhance the possibilities for using crop residues as an energy source. The major process variables investigated include temperature, the amount and type of inoculum, buffer requirements, compaction, and pretreatment to control the initial available organic components that create pH problems. A pilot-scale reactor operation on corn stover at a temperature of 550 C, with 25 percent initial total solids, a seed-to-feed ratio of 2.5 percent, and a buffer-to-feed ratio of 8 percent achieved 33 percent total volatile solids destruction in 60 days. Volumetric biogas yields from this unit were greater than 1 vol/vol day for 12 days, and greater than 0.5 vol/vol day for 32 days, at a substrate density of 169 kg/m (3).

  2. RESIDUAL RISK ASSESSMENT: SYNTHETIC ORGANIC ...

    EPA Pesticide Factsheets

    This document describes the residual risk assessment for the Synthetic Organic Chemical Manufacturing Industry source category. For stationary sources, section 112 (f) of the Clean Air Act requires EPA to assess risks to human health and the environment following implementation of technology-based control standards. If these technology-based control standards do not provide an ample margin of safety, then EPA is required to promulgate addtional standards. This document describes the methodology and results of the residual risk assessment performed for the Synthetic Organic Chemical Manufacturing Industry source category. The results of this analyiss will assist EPA in determining whether a residual risk rule for this source category is appropriate. Update 9/19/2006: Proposed Rule June 14, 2006 - Risk Assessment complete September 2005 and only available in the Docket.

  3. Chemistry of combined residual chlorination

    SciTech Connect

    Leao, S.F.; Selleck, R.E.

    1982-01-01

    The decay of the combined chlorine residual was investigated in this work. Recent concerns about the formation of undesirable compounds such as chloroform with free residual chlorination have focused attention on the alternative use of combined residual chlorination. This work investigates the applicability of reactions proposed to describe the transformations and decay of the combined residual with time. Sodium hypochlorite was added to buffered solutions of ammonia with the chlorine residual being monitored over periods extending up to 10 days. The reaction was studied at four initial concentrations of hypochlorite of 100, 50, 25 and 10 mg/L as Cl/sub 2/ with molar application ratios of chlorine to ammonia, defined herein as M ratios, of 0.90, 0.50, 0.25 and 0.05 at each hypochlorite dose. Sixty-eight experiments were conducted at the pH of 6.6 and 7.2. The conclusions are: (1) in the absence of free chlorine, the concentration of NH/sub 3/ does not seem to affect the rate of disappearance of the residual other than through the formation of NHCl/sub 2/ by NH/sub 2/Cl hydrolysis; (2) the reaction between NHCl/sub 2/ and NH/sub 4//sup +/ to form NH/sub 2/Cl is either much slower than reported by Gray et. al. or the mechanism is different with a rate limiting step not involving NH/sub 3/ or NH/sub 4//sup +/; (3) a redox reaction in addition to the first-order decomposition of NHCl/sub 2/ appears necessary. Model simulation results indicated that a reaction of the type NH/sub 2/Cl + NHCl/sub 2/ ..-->.. P added to the first-order NHCl/sub 2/ decomposition can explain the results observed except at the higher chlorine doses.

  4. Notch Signaling Limits Supporting Cell Plasticity in the Hair Cell-Damaged Early Postnatal Murine Cochlea

    PubMed Central

    Korrapati, Soumya; Roux, Isabelle; Glowatzki, Elisabeth; Doetzlhofer, Angelika

    2013-01-01

    In mammals, auditory hair cells are generated only during embryonic development and loss or damage to hair cells is permanent. However, in non-mammalian vertebrate species, such as birds, neighboring glia-like supporting cells regenerate auditory hair cells by both mitotic and non-mitotic mechanisms. Based on work in intact cochlear tissue, it is thought that Notch signaling might restrict supporting cell plasticity in the mammalian cochlea. However, it is unresolved how Notch signaling functions in the hair cell-damaged cochlea and the molecular and cellular changes induced in supporting cells in response to hair cell trauma are poorly understood. Here we show that gentamicin-induced hair cell loss in early postnatal mouse cochlear tissue induces rapid morphological changes in supporting cells, which facilitate the sealing of gaps left by dying hair cells. Moreover, we provide evidence that Notch signaling is active in the hair cell damaged cochlea and identify Hes1, Hey1, Hey2, HeyL, and Sox2 as targets and potential Notch effectors of this hair cell-independent mechanism of Notch signaling. Using Cre/loxP based labeling system we demonstrate that inhibition of Notch signaling with a γ- secretase inhibitor (GSI) results in the trans-differentiation of supporting cells into hair cell-like cells. Moreover, we show that these hair cell-like cells, generated by supporting cells have molecular, cellular, and basic electrophysiological properties similar to immature hair cells rather than supporting cells. Lastly, we show that the vast majority of these newly generated hair cell-like cells express the outer hair cell specific motor protein prestin. PMID:24023676

  5. Residual contact restraints in cryogenics

    NASA Astrophysics Data System (ADS)

    Cretegny, J. F.; Demonicault, J. M.

    The use of residual stress measurements to evaluate the state of cryogenic turbomachines, whose surfaces are worn by the working conductions in dry contact, is addressed. Their contribution to the understanding of the reasons of possible ruptures is considered. It is stated that residual stress measurements should be used as a complementary tool rather than as input data for models. It is shown, thanks to two examples concerning the ball bearings and splines of the liquid hydrogen turbopump of the Vulcain engine, what can be expected from such techniques. Total exploitation of the results has still to be done, but preliminary results are quite encouraging.

  6. Pesticide residues in olive oil.

    PubMed

    Lentza-Rizos, C; Avramides, E J

    1995-01-01

    The attacks of pests and diseases and the presence of weeds make it necessary to apply pesticides to olive trees to ensure crop protection. Residues of these compounds may remain and contaminate the oil produced. For the analysis of pesticide residues in olive oil, the most common methods are multiresidue methods for fatty substrates, based on partitioning between hexane or light petroleum and acetonitrile. Recently, other methods have been applied, such as ready-to-use, disposable minicolumns or direct injection of oil into a capillary gas chromatograph equipped with a precolumn with an oil recovery tank. Although several pesticides are registered in oil-producing countries for use on olive trees, available literature on the level and fate of residues is very limited. However, it is clear that fat-soluble pesticides tend to concentrate in the oil, both after full coverage and bait spraying, and their use close to harvest should therefore be avoided. Because it is sometimes necessary to use such pesticides late in autumn because of their effectiveness in cases of severe attack, residue trials should be carried out to determine the residue concentration in oil and to set a reasonable preharvest safety interval. Data produced by such trials would permit the establishment of MRLs (tolerances) in olive oil to cover cases where the residues, although relatively high, are not of toxicological significance for consumers (risk assessment). Such is the case with corn oil and the fat-soluble insecticide methyl pirimiphos, registered in the U.S. for use on corn. The U.S. EPA tolerance for methyl pirimiphos in corn is 8 mg/kg, whereas it is 11 times higher (88 mg/kg) for corn oil because it is known to concentrate in the oil. Similar provisions for olive oil, based on data from residue trials according to Good Agricultural Practice, the long-term toxicity of each pesticide as expressed by its ADI for man, and olive oil consumption patterns, would facilitate international trade

  7. Damage tolerance of candidate thermoset composites for use on single stage to orbit vehicles

    NASA Technical Reports Server (NTRS)

    Nettles, A. T.; Lance, D.; Hodge, A.

    1994-01-01

    Four fiber/resin systems were compared for resistance to damage and damage tolerance. One toughened epoxy and three toughened bismaleimide (BMI) resins were used, all with IM7 carbon fiber reinforcement. A statistical design of experiments technique was used to evaluate the effects of impact energy, specimen thickness, and impactor diameter on the damage area, as computed by C-scans, and residual compression-after-impact (CAI) strength. Results showed that two of the BMI systems sustained relatively large damage zones yet had an excellent retention of CAI strength.

  8. Comparative investigation of damage performance on K9 and SiO2 under 1064-nm nanosecond laser irradiation

    NASA Astrophysics Data System (ADS)

    Liu, Hongjie; Wang, Fengrui; Zhang, Zhen; Huang, Jin; Zhou, Xinda; Jiang, Xiaodong; Wu, Weidong; Zheng, Wanguo

    2011-11-01

    Laser damage performance of K9 glass and fused silica glass were tested respectively at same experimental condition with 1064 nm nanosecond laser. The initial damage threshold (IDT), the damage growth threshold (DGT) and the damage growth laws of the two optics glass were investigated comparatively. The results show that the damage growth behavior of the two glasses are quite different, for example, the lower damage growth threshold and the higher damage growth coefficient for K9 glass, which can attribute to the difference of the material's damage morphology, optical absorption, residual stress near damage site between the two optics glass. The research is very important to choose transparent optical material applied in high power laser.

  9. Comparative investigation of damage performance on K9 and SiO2 under 1064-nm nanosecond laser irradiation

    NASA Astrophysics Data System (ADS)

    Liu, Hongjie; Wang, Fengrui; Zhang, Zhen; Huang, Jin; Zhou, Xinda; Jiang, Xiaodong; Wu, Weidong; Zheng, Wanguo

    2012-01-01

    Laser damage performance of K9 glass and fused silica glass were tested respectively at same experimental condition with 1064 nm nanosecond laser. The initial damage threshold (IDT), the damage growth threshold (DGT) and the damage growth laws of the two optics glass were investigated comparatively. The results show that the damage growth behavior of the two glasses are quite different, for example, the lower damage growth threshold and the higher damage growth coefficient for K9 glass, which can attribute to the difference of the material's damage morphology, optical absorption, residual stress near damage site between the two optics glass. The research is very important to choose transparent optical material applied in high power laser.

  10. DNA damage and mutation. Types of DNA damage

    NASA Astrophysics Data System (ADS)

    Chakarov, Stoyan; Petkova, Rumena; Russev, George Ch; Zhelev, Nikolai

    2014-02-01

    This review outlines the basic types of DNA damage caused by exogenous and endogenous factors, analyses the possible consequences of each type of damage and discusses the need for different types of DNA repair. The mechanisms by which a minor damaging event to DNA may eventually result in the introduction of heritable mutation/s are reviewed. The major features of the role of DNA damage in ageing and carcinogenesis are outlined and the role of iatrogenic DNA damage in human health and disease (with curative intent as well as a long-term adverse effect of genotoxic therapies) are discussed in detail.

  11. Collection of sugarcane crop residue for energy

    SciTech Connect

    Eiland, B.R.; Clayton, J.E.

    1982-12-01

    Crop residue left after sugarcane harvesting was recovered using a forage harvester and a large round baler. The quantity, bulk density and moisture content of the crop residue was determined in four fields. Crop residue from 7 ha was burned in boilers at a sugar mill. Samples of this residue were tested by a laboratory and compared to sugarcane bagasse.

  12. Residual Structures in Latent Growth Curve Modeling

    ERIC Educational Resources Information Center

    Grimm, Kevin J.; Widaman, Keith F.

    2010-01-01

    Several alternatives are available for specifying the residual structure in latent growth curve modeling. Two specifications involve uncorrelated residuals and represent the most commonly used residual structures. The first, building on repeated measures analysis of variance and common specifications in multilevel models, forces residual variances…

  13. Fiber composite structural durability and damage tolerance: Simplified predictive methods

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.; Ginty, Carol A.

    1987-01-01

    Simplified predictive methods and models (theory) to evaluate fiber/polymer-matrix composite material for determining structural durability and damage tolerance are presented and described. This theory includes equations for (1) fatigue and fracture of composites without and with defects, (2) impact resistance and residual strength after impact, (3) thermal fatigue, and (4) combined stress fatigue. Several examples are included to illustrate applications of the theory and to identify significant parameters and sensitivities. Comparisons with limited experimental data are made.

  14. Low Level Laser Retinal Damage

    DTIC Science & Technology

    1990-03-01

    18 Related Projects ........................ . . ....... 20 References . . . . .......................... 22 2 INTRODUCTION The objectives of...fluorescein is a potent phototoxic agent in the retina.26 The damage threshold for blue light retinal damage is lowered by a factor of ten after an... Related to the Probiem of Retinal Light Damage 1. Corneal Holography 2. Hematoporphyrin Studies 3. Fluorescein Fluorescence Measurements 7 EQUIPMENT

  15. Radiation damage in semiconductor detectors

    SciTech Connect

    Kraner, H.W.

    1981-12-01

    A survey is presented of the important damage-producing interactions in semiconductor detectors and estimates of defect numbers are made for MeV protons, neutrons and electrons. Damage effects of fast neutrons in germanium gamma ray spectrometers are given in some detail. General effects in silicon detectors are discussed and damage constants and their relationship to leakage current is introduced.

  16. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    A guard shack at the Shuttle Landing Facility, operated by Space Florida, is seen during a survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  17. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    An industrial building behind the Space Station Processing Facility (SSPF) is seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  18. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    The Central Campus construction site is seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm’s onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  19. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    The Operations Support Building I (OSB I) is seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The roof of the building is currently undergoing repair from Hurricane Matthew. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  20. Does orthodontics damage faces?

    PubMed

    DiBiase, A T; Sandler, P J

    2001-03-01

    With the increasing provision of orthodontic care in this country, certain practitioners have raised concerns regarding the use of elective extractions and retraction mechanics, especially the effects on the facial profile and the TMJ. The non-extraction versus extraction debate spans the history of orthodontics, and the concepts of facial attractiveness are subject to change as fashions change. Within the realms of evidence-based practice, there is little or no evidence to suggest that the philosophies and mechanics of contemporary orthodontics, in the vast majority of cases, cause damage to the profile or are directly linked to the development of TMJ dysfunction.

  1. Tokamak ARC damage

    SciTech Connect

    Murray, J.G.; Gorker, G.E.

    1985-01-01

    Tokamak fusion reactors will have large plasma currents of approximately 10 MA with hundreds of megajoules stored in the magnetic fields. When a major plasma instability occurs, the disruption of the plasma current induces voltage in the adjacent conducting structures, giving rise to large transient currents. The induced voltages may be sufficiently high to cause arcing across sector gaps or from one protruding component to another. This report reviews a tokamak arcing scenario and provides guidelines for designing tokamaks to minimize the possibility of arc damage.

  2. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    The Mobile Launcher (ML), Vehicle Assembly Building (VAB), Launch Control Center (LCC), and Launch Complex 39 surrounding areas are seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  3. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    The Mobile Launcher (ML), Launch Control Center (LCC), Vehicle Assembly Building (VAB), and Launch Complex 39 surrounding areas are seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  4. Hurricane Irma Damage Assessment

    NASA Image and Video Library

    2017-09-12

    The Vehicle Assembly Building (VAB), Launch Control Center (LCC), and Launch Complex 39 surrounding areas are seen during an aerial survey of NASA's Kennedy Space Center in Florida on September 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on September 10, 2017. NASA closed the center ahead of the storm's onset and only a small team of specialists known as the Rideout Team was on the center as the storm approached and passed.

  5. Structural integrity of fuselage panels with multisite damage

    NASA Astrophysics Data System (ADS)

    Park, Jai H.; Singh, Ripudaman; Pyo, Chang R.; Atluris, Satya N.

    1995-05-01

    Structural integrity assessment of aging flight vehicles is extremely important to ensure their economic and safe operation. A two-step analytical approach, developed to estimate the residual strength of pressurized fuselage stiffened shell panels with multi-bay fatigue cracking is presented in this article. Conventional finite element analysis of the damaged multibay panel is first carried out to obtain the load flow pattern through it. The Schwartz-Neumann alternating method is then applied to the fuselage skin with multiple site damage, to obtain stresses and the relevant crack tip parameters that govern the onset of fracture. Fracture mechanics as well as net section yield criteria are used to evaluate the static residual strength. The presence of holes with or without multisite damage ahead of a dominant crack is found to significantly degrade the capacity of the fuselage shell panels to sustain static internal pressure. An elastic-plastic alternating method is newly developed and applied to evaluate the residual strength of flat panels with multiple cracks. The computational methodologies presented herein are marked improvements to the present state-of-the-art, and are extremely efficient, both from engineering manpower as well as computational costs point of view. Once verified, they can very well complement the experimental requirements, reducing the cost of structural integrity assessment programs.

  6. Choosing forest residues management alternatives.

    Treesearch

    John M. Pierovich; Richard C. Smith

    1973-01-01

    Forest residues management involves disposal, modification, or utilization of wood products. The costs and benefits of the several alternatives available to forest managers must be evaluated in relation to land management goals and constraints in four areas: (1) unused wood fiber, (2) conflagrations, (3) impairment of forest resources, and (4) opposition to treatment...

  7. Residual Stresses in Ground Steels.

    DTIC Science & Technology

    1979-06-13

    stress near the surface can be lower. The level of residual stress is also strongly affected by carbon,’3 which influences the microplastic behaviour of...1966, Vol. 14, 99-104. 14. C. 3. )4cMahon: “ Microplastic Behaviour in Iron” in Mv. in Mater . S d . Res., Vol. 2, 121-140, Interscience, New York

  8. Managing woodwaste: Yield from residue

    SciTech Connect

    Nielson, E.; Rayner, S.

    1993-12-31

    Historically, the majority of sawmill waste has been burned or buried for the sole purpose of disposal. In most jurisdictions, environmental legislation will prohibit, or render uneconomic, these practices. Many reports have been prepared to describe the forest industry`s residue and its environmental effect; although these help those looking for industry-wide or regional solutions, such as electricity generation, they have limited value for the mill manager, who has the on-hands responsibility for generation and disposal of the waste. If the mill manager can evaluate waste streams and break them down into their usable components, he can find niche market solutions for portions of the plant residue and redirect waste to poor/no-return, rather than disposal-cost, end uses. In the modern mill, residue is collected at the individual machine centre by waste conveyors that combine and mix sawdust, shavings, bark, etc. and send the result to the hog-fuel pile. The mill waste system should be analyzed to determine the measures that can improve the quality of residues and determine the volumes of any particular category before the mixing, mentioned above, occurs. After this analysis, the mill may find a niche market for a portion of its woodwaste.

  9. Potential hazards of fumigant residues.

    PubMed Central

    Fishbein, L

    1976-01-01

    A spectrum of fumigants (primarily ethylene dibromide, 1,2-dibromo-3-chloropropane, ethylene oxide, symdibromotetetrachloroethane, 1,3-dichloropropene, dichlorovos, carbon tetrachloride, methyl bromide) as well as their degradation products in foodstuffs and soil have been examined mainly in regard to the potential mutagenicity of their residues. PMID:789068

  10. Thoracic damage control surgery.

    PubMed

    Gonçalves, Roberto; Saad, Roberto

    2016-01-01

    The damage control surgery came up with the philosophy of applying essential maneuvers to control bleeding and abdominal contamination in trauma patients who are within the limits of their physiological reserves. This concept was extended to thoracic injuries, where relatively simple maneuvers can shorten operative time of in extremis patients. This article aims to revise the various damage control techniques in thoracic organs that must be known to the surgeon engaged in emergency care. RESUMO A cirurgia de controle de danos surgiu com a filosofia de se aplicar manobras essenciais para controle de sangramento e contaminação abdominal, em doentes traumatizados, nos limites de suas reservas fisiológicas. Este conceito se estendeu para as lesões torácicas, onde manobras relativamente simples, podem abreviar o tempo operatório de doentes in extremis. Este artigo tem como objetivo, revisar as diversas técnicas de controle de dano em órgãos torácicos, que devem ser de conhecimento do cirurgião que atua na emergência.

  11. Damage Control Resuscitation.

    PubMed

    Bogert, James N; Harvin, John A; Cotton, Bryan A

    2016-03-01

    Resuscitation of the hemorrhaging patient has undergone significant changes in the last decade resulting in the concept of damage control resuscitation (DCR). Hemostatic resuscitation aims to address the physiologic derangements found in the hemorrhaging patient, namely coagulopathy, acidosis, and hypothermia. Strategies to achieve this are permissive hypotension, high ratio of plasma and platelet transfusion to packed red blood cell transfusion, and limitation of crystalloid administration. Damage control surgery aims for early hemorrhage control and minimizing operative time by delaying definitive repair until the patient's physiologic status has normalized. Together these strategies constitute DCR and have led to improved outcomes for hemorrhaging patients over the last 2 decades. Recently, DCR has been augmented by both pharmacologic and laboratory adjuncts to improve the care of the hemorrhaging patient. These include thrombelastography as a detailed measure of the clotting cascade, tranexamic acid as an antifibrinolytic, and the procoagulant activated factor VII. In this review, we discuss the strategies that makeup DCR, their adjuncts, and how they fit into the care of the hemorrhaging patient.

  12. Drugs and gastric damage.

    PubMed

    Cooke, A R

    1976-01-01

    The effects of aspirin, salicylate formulations and substitutes, smoking (nicotine), indomethacin, corticosteroids, phenylbutazone, ethanol, caffeine and reserpine on the gastric mucosa are discussed. The damaging effects of the drugs are considered in terms of the gastric mucosal barrier, gastric erosions, microbleeding and haematemesis and melaena and finally whether they cause peptic ulcer. There is suggestive evidence that unbuffered aspirin is a cause of haematemesis and melaena and of gastric ulcer but the incidence rates for hospital admission are low, being 10 to 15 per 100,000 heavy users per year. Aspirin in solution as acetylsalicylate buffered to maintain a neutral pH protects against gastric damage. Newer aspirin substitutes (mefenamic acid, fenoprofen, naproxen, tolmetin and ibuprofen) appear to cause less faecal blood loss than aspirin but their long-term effects have not been fully evaluated. Smoking is definitely associated with peptic ucler but the mechanism is unknown. Corticosteroids are probably not ulcerogenic despite clinical bias that they are. Indomethacin and phenylbutazone may be ulcerogenic but there is insufficient evidence to make firm judgements. Ethanol, caffeine and reserpine, on available evidence, are probably not ulcerogenic.

  13. Vibration-based damage detection for filament wound pressure vessel filled with fluid

    NASA Astrophysics Data System (ADS)

    Zhou, W.; Wu, Z.; Li, H.

    2008-03-01

    Filament wound pressure vessels have been extensively used in industry and engineering. The existing damage detection and health monitoring methods for these vessels, such as X-ray and ultrasonic scan, can not meet the requirement of online damage detection; moreover optical grating fibre can only sense the local damage, but not the damage far away from the location of sensors. Vibration-based damage detection methods have the potential to meet such requirements. There methods are based on the fact that damages in a structure results in a change in structural dynamic characteristics. A damage detection method based on a residual associated with output-only subspace-based modal identification and global or focused chi^2-tests built on that residual has been proposed and successfully experimented on a variety of test cases. The purpose of this work is to describe the damage detection method and apply this method to assess the composite structure filled with fluid. The results of identification and damage detection will be presented.

  14. Measurement of residual stress in bent pipelines

    NASA Astrophysics Data System (ADS)

    Alers, G. A.; McColskey, J. D.

    2002-05-01

    Buried gas and oil pipelines can be subjected to unexpected bending loads caused by such earth movements as earthquakes, wash-outs, road building, or mining subsidence as well as by denting from unintentional digging. In order to make a fitness-for-service assessment, it is necessary to measure any residual stresses that are left in the pipe wall as well as the degree of plastic flow within regions of severe damage. A portable instrument that uses EMATs to rapidly measure ultrasonic shear wave birefringence in the wall of a pipe has been developed and applied to a 5 m (15 ft) long section of 0.56 m (22 in) diameter linepipe loaded in three point bending by a 22 MN (five million pound) load frame. The results showed that: (1) a large correction for shear wave anisotropy caused by texture in the steel had to be introduced and (2) the degree of plastic flow could be deduced from changes in the texture contribution alone. An attempt to separate the stress and texture effects by using SH wave modes in the pipe wall proved unreliable because of magnetostrictive effects in the periodic permanent magnet EMATs used for these experiments.

  15. Crack Growth Simulation and Residual Strength Prediction in Airplane Fuselages

    NASA Technical Reports Server (NTRS)

    Chen, Chuin-Shan; Wawrzynek, Paul A.; Ingraffea, Anthony R.

    1999-01-01

    This is the final report for the NASA funded project entitled "Crack Growth Prediction Methodology for Multi-Site Damage." The primary objective of the project was to create a capability to simulate curvilinear fatigue crack growth and ductile tearing in aircraft fuselages subjected to widespread fatigue damage. The second objective was to validate the capability by way of comparisons to experimental results. Both objectives have been achieved and the results are detailed herein. In the first part of the report, the crack tip opening angle (CTOA) fracture criterion, obtained and correlated from coupon tests to predict fracture behavior and residual strength of built-up aircraft fuselages, is discussed. Geometrically nonlinear, elastic-plastic, thin shell finite element analyses are used to simulate stable crack growth and to predict residual strength. Both measured and predicted results of laboratory flat panel tests and full-scale fuselage panel tests show substantial reduction of residual strength due to the occurrence of multi-site damage (MSD). Detailed comparisons of n stable crack growth history, and residual strength between the predicted and experimental results are used to assess the validity of the analysis methodology. In the second part of the report, issues related to crack trajectory prediction in thin shells; an evolving methodology uses the crack turning phenomenon to improve the structural integrity of aircraft structures are discussed, A directional criterion is developed based on the maximum tangential stress theory, but taking into account the effect of T-stress and fracture toughness orthotropy. Possible extensions of the current crack growth directional criterion to handle geometrically and materially nonlinear problems are discussed. The path independent contour integral method for T-stress evaluation is derived and its accuracy is assessed using a p- and hp-version adaptive finite element method. Curvilinear crack growth is simulated in

  16. High residue amounts of kaolin further increase photosynthesis and fruit color in 'Empire' apple

    USDA-ARS?s Scientific Manuscript database

    Kaolin (Surround WP, NovaSource, Phoenix, AZ, USA) is commonly used to reduce sunburn damage in fruit crops and to reduce heat stress on foliage. It is typically applied at rates of 3% to 6%, resulting in leaf and fruit residue levels of 1-3 g/m2. Crop modeling of the effect of kaolin on leaf/cano...

  17. Residual stress evaluation and fatigue life prediction in the welded joint by x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Yoo, Keun Bong; Hwang, Kwon Tae; Chang, Jung Chel; Kim, Jae Hoon

    2009-07-01

    In the fossil power plant, the reliability of the components which consist of the many welded parts depends on the quality of welding. The residual stress is occurred by the heat flux of high temperature during weld process. This decreases the mechanical properties as the strength of fatigue and fracture. The residual stress of the welded part in the recently constructed power plants has been the cause of a variety of accidents. The objective of this study is measurement of the residual stress and the full width at half maximum intensity (FWHM) by X-ray diffraction method and to estimate the feasibility of this application for fatigue life assessment of the high-temperature pipeline. The materials used for the study is P92 steel for the use of high temperature pipe on super critical condition. The test results were analyzed by the distributed characteristics of residual stresses and FWHM in x-ray diffraction intensity curve. Also, X-ray diffraction tests using specimens simulated low cycle fatigue damage were performed in order to analyze fatigue properties when fatigue damage conditions become various stages. As a result of X-ray diffraction tests for specimens simulated fatigue damages, we conformed that the ratio of the FWHM due to fatigue damage has linear relationship with fatigue life ratio algebraically. From this relationship, it was suggested that direct expectation of the life consumption rate was feasible.

  18. Effects of seasonal prescribved fires on residual overstory trees in oak-dominate shelterwood stands

    Treesearch

    Patrick H. Brose; David H. Van Lear

    1999-01-01

    A study was initiated in 1994 to evaluate the degree of bole damage and crown decline residual overstory trees would experience because of prescribed burning of shelterwood stands. Three oak-dominated shelterwood stands, partially harvested 2 to 4 yr earlier, were divided into four treatments (unburned control, spring burn, summer burn, and winter burn). Fifteen...

  19. Surface state reconstruction in ion-damaged SmB6

    SciTech Connect

    Wakeham, N.; Wang, Y. Q.; Fisk, Z.; Ronning, F.; Thompson, J. D.

    2015-02-12

    We have used ion-irradiation to damage the (001) surfaces of SmB₆ single crystals to varying depths, and have measured the resistivity as a function of temperature for each depth of damage. We observe a reduction in the residual resistivity with increasing depth of damage. Our data are consistent with a model in which the surface state is not destroyed by the ion-irradiation, however instead the damaged layer is poorly conducting and the initial surface state is reconstructed below the damage. This behavior is consistent with a surface state that is topologically protected.

  20. An empirical modified fatigue damage model for impacted GFRP laminates

    NASA Astrophysics Data System (ADS)

    Naderi, S.; Hassan, M. A.; Bushroa, A. R.

    2014-10-01

    The aim of the present paper is to evaluate the residual strength of GFRP laminates following a low-velocity impact event under cyclic loading. The residual strength is calculated using a linear fatigue damage model. According to an investigation into the effect of low-velocity impact on the fatigue behavior of laminates, it seems laminate fatigue life decreases after impact. By normalizing the fatigue stress against undamaged static strength, the Fatigue Damage parameter “FD” is presented with a linear relationship as its slope which is a linear function of the initial impact energy; meanwhile, the constants were attained from experimental data. FD is implemented into a plane-stress continuum damage mechanics based model for GFRP composite laminates, in order to predict damage threshold in composite structures. An S-N curve is implemented to indicate the fatigue behavior for 2 mm thickness encompassing both undamaged and impacted samples. A decline in lifespan is evident when the impact energy level increases. Finally, the FD is intended to capture the unique GFRP composite characteristics.

  1. Non-repair Pathways for Minimizing Protein Isoaspartyl Damage in the Yeast Saccharomyces cerevisiae*

    PubMed Central

    Patananan, Alexander N.; Capri, Joseph; Whitelegge, Julian P.; Clarke, Steven G.

    2014-01-01

    The spontaneous degradation of asparaginyl and aspartyl residues to isoaspartyl residues is a common type of protein damage in aging organisms. Although the protein-l-isoaspartyl (d-aspartyl) O-methyltransferase (EC 2.1.1.77) can initiate the repair of l-isoaspartyl residues to l-aspartyl residues in most organisms, no gene homolog or enzymatic activity is present in the budding yeast Saccharomyces cerevisiae. Therefore, we used biochemical approaches to elucidate how proteins containing isoaspartyl residues are metabolized in this organism. Surprisingly, the level of isoaspartyl residues in yeast proteins (50–300 pmol of isoaspartyl residues/mg of protein extract) is comparable with organisms with protein-l-isoaspartyl (d-aspartyl) O-methyltransferase, suggesting a novel regulatory pathway. Interfering with common protein quality control mechanisms by mutating and inhibiting the proteasomal and autophagic pathways in vivo did not increase isoaspartyl residue levels compared with wild type or uninhibited cells. However, the inhibition of metalloproteases in in vitro aging experiments by EDTA resulted in an ∼3-fold increase in the level of isoaspartyl-containing peptides. Characterization by mass spectrometry of these peptides identified several proteins involved in metabolism as targets of isoaspartyl damage. Further analysis of these peptides revealed that many have an N-terminal isoaspartyl site and originate from proteins with short half-lives. These results suggest that one or more metalloproteases participate in limiting isoaspartyl formation by robust proteolysis. PMID:24764295

  2. Non-repair pathways for minimizing protein isoaspartyl damage in the yeast Saccharomyces cerevisiae.

    PubMed

    Patananan, Alexander N; Capri, Joseph; Whitelegge, Julian P; Clarke, Steven G

    2014-06-13

    The spontaneous degradation of asparaginyl and aspartyl residues to isoaspartyl residues is a common type of protein damage in aging organisms. Although the protein-l-isoaspartyl (d-aspartyl) O-methyltransferase (EC 2.1.1.77) can initiate the repair of l-isoaspartyl residues to l-aspartyl residues in most organisms, no gene homolog or enzymatic activity is present in the budding yeast Saccharomyces cerevisiae. Therefore, we used biochemical approaches to elucidate how proteins containing isoaspartyl residues are metabolized in this organism. Surprisingly, the level of isoaspartyl residues in yeast proteins (50-300 pmol of isoaspartyl residues/mg of protein extract) is comparable with organisms with protein-l-isoaspartyl (d-aspartyl) O-methyltransferase, suggesting a novel regulatory pathway. Interfering with common protein quality control mechanisms by mutating and inhibiting the proteasomal and autophagic pathways in vivo did not increase isoaspartyl residue levels compared with wild type or uninhibited cells. However, the inhibition of metalloproteases in in vitro aging experiments by EDTA resulted in an ∼3-fold increase in the level of isoaspartyl-containing peptides. Characterization by mass spectrometry of these peptides identified several proteins involved in metabolism as targets of isoaspartyl damage. Further analysis of these peptides revealed that many have an N-terminal isoaspartyl site and originate from proteins with short half-lives. These results suggest that one or more metalloproteases participate in limiting isoaspartyl formation by robust proteolysis.

  3. Age-dependent changes in damage processes of hair cuticle.

    PubMed

    Takahashi, Toshie; Mamada, Akira; Breakspear, Steven; Itou, Takashi; Tanji, Noriyuki

    2015-03-01

    Human hair cuticle is always exposed to various stresses and then gradually lost in daily life. There are two typical patterns of cuticle damage: type L, where the cell membrane complex, the structure located between cuticle cells, is split and the cuticle lifts up, and type E, where the fragile substructure of the cuticle cell (endocuticle) is damaged so that its rugged residue is exposed. We previously reported that type L damage preferentially occurs in the case of Japanese females in their 20s to 40s. This study aims to elucidate the age-dependent change of cuticle and its effect on hair properties. Hair fibers collected from Japanese females (ranging from 10 to 70 years old) were evaluated in the aspects of inclination for each type of damage, resistance of cuticle against grooming stresses and content of fatty acid 18-MEA on hair surface. It was revealed that the dominant damage pattern shifts from type L to E with aging. Furthermore, the cuticle becomes gradually less resistant to daily grooming stress. The dominance of type E damage accelerates cuticle loss. Reduction of 18-MEA on weathered hair is accelerated with aging on elder hair. It has been reported that various age-dependent changes of whole hair shaft, such as diameter, density, elasticity, etc., occur in the age range of 40s and 50s. In this study, it was revealed that cuticle becomes more fragile and the hair surface properties deteriorate in the same age range. © 2015 Wiley Periodicals, Inc.

  4. Nondestructive damage evaluation in ceramic matrix composites for aerospace applications.

    PubMed

    Dassios, Konstantinos G; Kordatos, Evangelos Z; Aggelis, Dimitrios G; Matikas, Theodore E

    2013-01-01

    Infrared thermography (IRT) and acoustic emission (AE) are the two major nondestructive methodologies for evaluating damage in ceramic matrix composites (CMCs) for aerospace applications. The two techniques are applied herein to assess and monitor damage formation and evolution in a SiC-fiber reinforced CMC loaded under cyclic and fatigue loading. The paper explains how IRT and AE can be used for the assessment of the material's performance under fatigue. IRT and AE parameters are specifically used for the characterization of the complex damage mechanisms that occur during CMC fracture, and they enable the identification of the micromechanical processes that control material failure, mainly crack formation and propagation. Additionally, these nondestructive parameters help in early prediction of the residual life of the material and in establishing the fatigue limit of materials rapidly and accurately.

  5. Nondestructive Damage Evaluation in Ceramic Matrix Composites for Aerospace Applications

    PubMed Central

    Dassios, Konstantinos G.; Kordatos, Evangelos Z.; Aggelis, Dimitrios G.; Matikas, Theodore E.

    2013-01-01

    Infrared thermography (IRT) and acoustic emission (AE) are the two major nondestructive methodologies for evaluating damage in ceramic matrix composites (CMCs) for aerospace applications. The two techniques are applied herein to assess and monitor damage formation and evolution in a SiC-fiber reinforced CMC loaded under cyclic and fatigue loading. The paper explains how IRT and AE can be used for the assessment of the material's performance under fatigue. IRT and AE parameters are specifically used for the characterization of the complex damage mechanisms that occur during CMC fracture, and they enable the identification of the micromechanical processes that control material failure, mainly crack formation and propagation. Additionally, these nondestructive parameters help in early prediction of the residual life of the material and in establishing the fatigue limit of materials rapidly and accurately. PMID:23935428

  6. The effect of yield strength and ductility to fatigue damage

    NASA Technical Reports Server (NTRS)

    Yeh, H. Y.

    1973-01-01

    The cumulative damage of aluminium alloys with different yield strength and various ductility due to seismic loads was studied. The responses of an idealized beam with a centered mass at one end and fixed at the other end to El Centro's and Taft's earthquakes are computed by assuming that the alloys are perfectly elastoplastic materials and by using numerical technique. Consequently, the corresponding residual plastic strain can be obtained from the stress-strain relationship. The revised Palmgren-Miner cumulative damage theorem is utilized to calculate the fatigue damage. The numerical results show that in certain cases, the high ductility materials are more resistant to seismic loads than the high yield strength materials. The results also show that if a structure collapse during the earthquake, the collapse always occurs in the very early stage.

  7. Quantification of residual stress from photonic signatures of fused silica

    SciTech Connect

    Cramer, K. Elliott; Yost, William T.; Hayward, Maurice

    2014-02-18

    A commercially available grey-field polariscope (GFP) instrument for photoelastic examination is used to assess impact damage inflicted upon the outer-most pane of Space Shuttle windows made from fused silica. A method and apparatus for calibration of the stress-optic coefficient using four-point bending is discussed. The results are validated on known material (acrylic) and are found to agree with literature values to within 6%. The calibration procedure is then applied to fused-silica specimens and the stress-optic coefficient is determined to be 2.43 ± 0.54 × 10{sup −12} Pa{sup −1}. Fused silica specimens containing impacts artificially made at NASA’s Hypervelocity Impact Technology Facility (HIT-F), to simulate damage typical during space flight, are examined. The damage sites are cored from fused silica window carcasses and examined with the GFP. The calibrated GFP measurements of residual stress patterns surrounding the damage sites are presented.

  8. Crack arrest and residual strength of composite panels with softening strips

    SciTech Connect

    Chu, C.S. )

    1991-01-01

    The residual strength and crack-arresting capabilities of laminates with softening strips of either E-glass, Kevlar, or S-glass are investigated. Sixteen-ply panels (with strips replacing the 0 deg-ply fibers) are tested under different conditions including fatigue cycling (before and after an initial damage is introduced), and exposure to environmental moisture. It is found that S-glass functions better than Kevlar and E-glass in the crack-arrest and residual strength test (even though it experiences greater delamination than the other two materials); that the residual strength is not influenced by the size of the initial damage; and that moisture significantly affects the crack-arrest capability. It is concluded that these materials cannot be used as a crack-arrest mechanism for the fail-safe design of composite aircraft structures. 8 refs.

  9. Multivariate pluvial flood damage models

    SciTech Connect

    Van Ootegem, Luc; Verhofstadt, Elsy; Van Herck, Kristine; Creten, Tom

    2015-09-15

    Depth–damage-functions, relating the monetary flood damage to the depth of the inundation, are commonly used in the case of fluvial floods (floods caused by a river overflowing). We construct four multivariate damage models for pluvial floods (caused by extreme rainfall) by differentiating on the one hand between ground floor floods and basement floods and on the other hand between damage to residential buildings and damage to housing contents. We do not only take into account the effect of flood-depth on damage, but also incorporate the effects of non-hazard indicators (building characteristics, behavioural indicators and socio-economic variables). By using a Tobit-estimation technique on identified victims of pluvial floods in Flanders (Belgium), we take into account the effect of cases of reported zero damage. Our results show that the flood depth is an important predictor of damage, but with a diverging impact between ground floor floods and basement floods. Also non-hazard indicators are important. For example being aware of the risk just before the water enters the building reduces content damage considerably, underlining the importance of warning systems and policy in this case of pluvial floods. - Highlights: • Prediction of damage of pluvial floods using also non-hazard information • We include ‘no damage cases’ using a Tobit model. • The damage of flood depth is stronger for ground floor than for basement floods. • Non-hazard indicators are especially important for content damage. • Potential gain of policies that increase awareness of flood risks.

  10. Catalytic combustion of residual fuels

    NASA Technical Reports Server (NTRS)

    Bulzan, D. L.; Tacina, R. R.

    1981-01-01

    A noble metal catalytic reactor was tested using two grades of petroleum derived residual fuels at specified inlet air temperatures, pressures, and reference velocities. Combustion efficiencies greater than 99.5 percent were obtained. Steady state operation of the catalytic reactor required inlet air temperatures of at least 800 K. At lower inlet air temperatures, upstream burning in the premixing zone occurred which was probably caused by fuel deposition and accumulation on the premixing zone walls. Increasing the inlet air temperature prevented this occurrence. Both residual fuels contained about 0.5 percent nitrogen by weight. NO sub x emissions ranged from 50 to 110 ppm by volume at 15 percent excess O2. Conversion of fuel-bound nitrogen to NO sub x ranged from 25 to 50 percent.

  11. Limits of adaptation, residual interferences

    NASA Technical Reports Server (NTRS)

    Mokry, Miroslav (Editor); Erickson, J. C., Jr.; Goodyer, Michael J.; Mignosi, Andre; Russo, Giuseppe P.; Smith, J.; Wedemeyer, Erich H.; Newman, Perry A.

    1990-01-01

    Methods of determining linear residual wall interference appear to be well established theoretically; however they need to be validated, for example by comparative studies of test data on the same model in different adaptive-wall wind tunnels as well as in passive, ventilated-wall tunnels. The GARTEur CAST 7 and the CAST 10/DOA 2 investigations are excellent examples of such comparative studies. Results to date in both one-variable and two-variable methods for nonlinear wall interference indicate that a great deal more research and validation are required. The status in 2D flow is advanced over that in 3D flow as is the case generally with adaptive-wall development. Nevertheless, it is now well established that for transonic testing with extensive supercritical flow present, significant wall interference is likely to exist in conventional ventilated test sections. Consequently, residual correction procedures require further development hand-in-hand with further adaptive-wall development.

  12. 40 CFR 180.185 - DCPA; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...; tolerances for residues. (a) General. Tolerances for the combined residues of the herbicide dimethyl... residues of the herbicide dimethyl tetrachloroterephthalate (DCPA) and its metabolites monomethyl... residues. Tolerances are established for the combined indirect or inadvertent residues of the...

  13. 40 CFR 180.185 - DCPA; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...; tolerances for residues. (a) General. Tolerances for the combined residues of the herbicide dimethyl... residues of the herbicide dimethyl tetrachloroterephthalate (DCPA) and its metabolites monomethyl... residues. Tolerances are established for the combined indirect or inadvertent residues of the...

  14. 40 CFR 180.185 - DCPA; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...; tolerances for residues. (a) General. Tolerances for the combined residues of the herbicide dimethyl... residues of the herbicide dimethyl tetrachloroterephthalate (DCPA) and its metabolites monomethyl... residues. Tolerances are established for the combined indirect or inadvertent residues of the...

  15. 40 CFR 180.185 - DCPA; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...; tolerances for residues. (a) General. Tolerances for the combined residues of the herbicide dimethyl... residues of the herbicide dimethyl tetrachloroterephthalate (DCPA) and its metabolites monomethyl... residues. Tolerances are established for the combined indirect or inadvertent residues of the...

  16. 40 CFR 180.185 - DCPA; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...; tolerances for residues. (a) General. Tolerances for the combined residues of the herbicide dimethyl... residues of the herbicide dimethyl tetrachloroterephthalate (DCPA) and its metabolites monomethyl... residues. Tolerances are established for the combined indirect or inadvertent residues of the...

  17. The effect of residual gas scattering on Ga ion beam patterning of graphene

    SciTech Connect

    Thissen, Nick F. W. E-mail: a.a.bol@tue.nl; Vervuurt, R. H. J.; Weber, J. W.; Kessels, W. M. M.; Bol, A. A. E-mail: a.a.bol@tue.nl; Mulders, J. J. L.

    2015-11-23

    The patterning of graphene by a 30 kV Ga{sup +} focused ion beam (FIB) is studied by in-situ and ex-situ Raman spectroscopy. It is found that the graphene surrounding the patterned target area can be damaged at remarkably large distances of more than 10 μm. We show that scattering of the Ga ions in the residual gas of the vacuum system is the main cause of the large range of lateral damage, as the size and shape of the tail of the ion beam were strongly dependent on the system background pressure. The range of the damage was therefore greatly reduced by working at low pressures and limiting the total amount of ions used. This makes FIB patterning a feasible alternative to electron beam lithography as long as residual gas scattering is taken into account.

  18. Calcination/dissolution residue treatment

    SciTech Connect

    Knight, R.C.; Creed, R.F.; Patello, G.K.; Hollenberg, G.W.; Buehler, M.F.; O`Rourke, S.M.; Visnapuu, A.; McLaughlin, D.F.

    1994-09-01

    Currently, high-level wastes are stored underground in steel-lined tanks at the Hanford site. Current plans call for the chemical pretreatment of these wastes before their immobilization in stable glass waste forms. One candidate pretreatment approach, calcination/dissolution, performs an alkaline fusion of the waste and creates a high-level/low-level partition based on the aqueous solubilities of the components of the product calcine. Literature and laboratory studies were conducted with the goal of finding a residue treatment technology that would decrease the quantity of high-level waste glass required following calcination/dissolution waste processing. Four elements, Fe, Ni, Bi, and U, postulated to be present in the high-level residue fraction were identified as being key to the quantity of high-level glass formed. Laboratory tests of the candidate technologies with simulant high-level residues showed reductive roasting followed by carbonyl volatilization to be successful in removing Fe, Ni, and Bi. Subsequent bench-scale tests on residues from calcination/dissolution processing of genuine Hanford Site tank waste showed Fe was separated with radioelement decontamination factors of 70 to 1,000 times with respect to total alpha activity. Thermodynamic analyses of the calcination of five typical Hanford Site tank waste compositions also were performed. The analyses showed sodium hydroxide to be the sole molten component in the waste calcine and emphasized the requirement for waste blending if fluid calcines are to be achieved. Other calcine phases identified in the thermodynamic analysis indicate the significant thermal reconstitution accomplished in calcination.

  19. Electromechanical Apparatus Measures Residual Stress

    NASA Technical Reports Server (NTRS)

    Chern, Engmin J.; Flom, Yury

    1993-01-01

    Nondestructive test exploits relationship between stress and eddy-current-probe resistance. Yields data on residual stress or strain in metal tension/compression specimen (stress or strain remaining in specimen when no stress applied from without). Apparatus is assembly of commercial equipment: tension-or-compression testing machine, eddy-current probe, impedance gain-and-phase analyzer measuring impedance of probe coil, and desktop computer, which controls other equipment and processes data received from impedance gain-and-phase analyzer.

  20. Pesticidal residues in animal tissues

    USGS Publications Warehouse

    DeWitt, J.B.; Menzie, C.M.; Adomaitis, V.A.; Reichel, W.L.

    1960-01-01

    Tests with penned starlings, rats, pheasants, and ducks indicated that each species differs in sensitivity to the various pesticides. Residues in tissues are proportional to the degree of exposure during area treatment and they are also found in animals shot six or more months after treatment. The presence of more than 20-30 ppm of DDT, 20 ppm of chlordan, and 6-20 ppm of heptachlor epoxide in quail tissues indicated that the birds had ingested lethal dosages of the pesticides.

  1. Electromechanical Apparatus Measures Residual Stress

    NASA Technical Reports Server (NTRS)

    Chern, Engmin J.; Flom, Yury

    1993-01-01

    Nondestructive test exploits relationship between stress and eddy-current-probe resistance. Yields data on residual stress or strain in metal tension/compression specimen (stress or strain remaining in specimen when no stress applied from without). Apparatus is assembly of commercial equipment: tension-or-compression testing machine, eddy-current probe, impedance gain-and-phase analyzer measuring impedance of probe coil, and desktop computer, which controls other equipment and processes data received from impedance gain-and-phase analyzer.

  2. A fracture mechanics analysis of impact damage in a thick composite laminate

    NASA Technical Reports Server (NTRS)

    Poe, C. C., Jr.

    1985-01-01

    Graphite/epoxy filament-wound cases (FWC) for the solid rocket motors of the space shuttle are being made by NASA. The FWC cases are wound with AS4W graphite fiber impregnated with an epoxy resin and are about 1.4 inches or more thick. Graphite-epoxy composite laminates, unlike metals, can be damaged easily by low velocity impacts of objects like dropped tools. The residual tension strength of the FWC laminate, after impact, is being studied at Langley Research Center. The conditions that give minimum visual evidence of damage are being emphasized. A fracture mechanics analysis was developed to predict the residual strength, after impact, using radiographs to measure the size of the damage and an equivalent surface crack to represent the damage.

  3. Geotechnical characteristics of residual soils

    SciTech Connect

    Townsend, F.C.

    1985-01-01

    Residual soils are products of chemical weathering and thus their characteristics are dependent upon environmental factors of climate, parent material, topography and drainage, and age. These conditions are optimized in the tropics where well-drained regions produce reddish lateritic soils rich in iron and aluminum sesquioxides and kaolinitic clays. Conversely, poorly drained areas tend towards montmorillonitic expansive black clays. Andosols develop over volcanic ash and rock regions and are rich in allophane (amorphous silica) and metastable halloysite. The geological origins greatly affect the resulting engineering characteristics. Both lateritic soils and andosols are susceptible to property changes upon drying, and exhibit compaction and strength properties not indicative of their classification limits. Both soils have been used successfully in earth dam construction, but attention must be given to seepage control through the weathered rock. Conversely, black soils are unpopular for embankments. Lateritic soils respond to cement stabilization and, in some cases, lime stabilization. Andosols should also respond to lime treatment and cement treatments if proper mixing can be achieved. Black expansive residual soils respond to lime treatment by demonstrating strength gains and decreased expansiveness. Rainfall induced landslides are typical of residual soil deposits.

  4. Actinide recovery from pyrochemical residues

    SciTech Connect

    Avens, L.R.; Clifton, D.G.; Vigil, A.R.

    1985-05-01

    We demonstrated a new process for recovering plutonium and americium from pyrochemical waste. The method is based on chloride solution anion exchange at low acidity, or acidity that eliminates corrosive HCl fumes. Developmental experiments of the process flow chart concentrated on molten salt extraction (MSE) residues and gave >95% plutonium and >90% americium recovery. The recovered plutonium contained <500 ppM americium and <2500 ppM magnesium. The process operates by sorbing PuCl/sub 6//sup 2 -/ from high-chloride low-acid solution. Americium and other metals are washed from the ion exchange column with lN HNO/sub 3/-4.8M NaCl. After elution, plutonium is recovered by hydroxide precipitation, and americium is recovered by NaHCO/sub 3/ precipitation. All filtrates from the process can be discardable as low-level contaminated waste. Production-scale experiments are in progress for MSE residues. Flow charts for actinide recovery from electro-refining and direct oxide reduction residues are presented and discussed.

  5. An anisotropic damage model for concrete structures under cyclic loading-uniaxial modeling

    NASA Astrophysics Data System (ADS)

    Long, Yuchuan; He, Yuming

    2017-05-01

    An anisotropic damage model is developed based on conventional rotating crack approach. It uses nonlinear unloading/linear reloading branches to model the hysteretic behavior of concrete. Two damage variables, determined by the ratio of accumulated dissipating energy to fracture energy, are introduced to represent the stiffness degradation in tension and compression. Three cyclic tests are simulated by this model and sensitivity analyses are conducted as well. The numerical responses calculated by the damage model are consistent with those obtained from the experiments. The numerical results reflect the nonlinear behavior observed in those tests, such as the damage-induced stiffness degradation, accumulation of residual deformation, energy dissipation caused by hysteretic behavior and stiffness recovery effect due to crack closure. Sensitivity analyses show that the damage exponents have significant influence on the computational accuracy. It is concluded that the anisotropic damage model is applicable to the nonlinear analyses of concrete structures subjected to cyclic loading.

  6. Visualizing the search for radiation-damaged DNA bases in real time

    NASA Astrophysics Data System (ADS)

    Lee, Andrea J.; Wallace, Susan S.

    2016-11-01

    The Base Excision Repair (BER) pathway removes the vast majority of damages produced by ionizing radiation, including the plethora of radiation-damaged purines and pyrimidines. The first enzymes in the BER pathway are DNA glycosylases, which are responsible for finding and removing the damaged base. Although much is known about the biochemistry of DNA glycosylases, how these enzymes locate their specific damage substrates among an excess of undamaged bases has long remained a mystery. Here we describe the use of single molecule fluorescence to observe the bacterial DNA glycosylases, Nth, Fpg and Nei, scanning along undamaged and damaged DNA. We show that all three enzymes randomly diffuse on the DNA molecule and employ a wedge residue to search for and locate damage. The search behavior of the Escherichia coli DNA glycosylases likely provides a paradigm for their homologous mammalian counterparts.

  7. Surface crack analysis applied to impact damage in a thick graphite-epoxy composite

    NASA Technical Reports Server (NTRS)

    Poe, C. C., Jr.; Harris, C. E.; Morris, D. H.

    1988-01-01

    The residual tensile strength of a thick graphite/epoxy composite with impact damage was predicted using surface crack analysis. The damage was localized to a region directly beneath the impact site and extended only part way through the laminate. The damaged region contained broken fibers, and the locus of breaks in each layer resembled a crack perpendicular to the direction of the fibers. In some cases, the impacts broke fibers without making a visible crater. The impact damage was represented as a semi-elliptical surface crack with length and depth equal to that of the impact damage. The maximum length and depth of the damage were predicted with a stress analysis and a maximum shear stress criterion. The predictions and measurements of strength were in good agreement.

  8. Tensile strength of composite sheets with unidirectional stringers and crack-like damage

    NASA Technical Reports Server (NTRS)

    Poe, C. C., Jr.

    1984-01-01

    The damage tolerance characteristics of metal tension panels with riveted and bonded stringers are well known. The stringers arrest unstable cracks and retard propagation of fatigue cracks. Residual strengths and fatigue lives are considerably greater than those of unstiffened or integrally stiffened sheets. The damage tolerance of composite sheets with bonded composite stringers loaded in tension was determined. Cracks in composites do not readily propagate in fatigue, at least not through fibers. Moreover, the residual strength of notched composites is sometimes even increased by fatigue loading. Therefore, the residual strength aspect of damage tolerance, and not fatigue crack propagation, was investigated. About 50 graphite/epoxy composite panels were made with two sheet layups and several stringer configurations. Crack-like slots were cut in the middle of the panels to simulate damage. The panels were instrumented and monotonically loaded in tension to failure. The tests indicate that the composite panels have considerable damage tolerance, much like metal panels. The stringers arrested cracks that ran from the crack-like slots, and the residual strengths were considerably greater than those of unstiffened composite sheets. A stress intensity factor analysis was developed to predict the failing strains of the stiffened panels. Using the analysis, a single design curve was produced for composite sheets with bonded stringers of any configuration.

  9. Alleviating inequality in climate policy costs: an integrated perspective on mitigation, damage and adaptation

    NASA Astrophysics Data System (ADS)

    De Cian, E.; Hof, A. F.; Marangoni, G.; Tavoni, M.; van Vuuren, D. P.

    2016-07-01

    Equity considerations play an important role in international climate negotiations. While policy analysis has often focused on equity as it relates to mitigation costs, there are large regional differences in adaptation costs and the level of residual damage. This paper illustrates the relevance of including adaptation and residual damage in equity considerations by determining how the allocation of emission allowances would change to counteract regional differences in total climate costs, defined as the costs of mitigation, adaptation, and residual damage. We compare emission levels resulting from a global carbon tax with two allocations of emission allowances under a global cap-and-trade system: one equating mitigation costs and one equating total climate costs as share of GDP. To account for uncertainties in both mitigation and adaptation, we use a model-comparison approach employing two alternative modeling frameworks with different damage, adaptation cost, and mitigation cost estimates, and look at two different climate goals. Despite the identified model uncertainties, we derive unambiguous results on the change in emission allowance allocation that could lessen the unequal distribution of adaptation costs and residual damages through the financial transfers associated with emission trading.

  10. 7 CFR 51.2090 - Serious damage.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Standards for Grades of Almonds in the Shell Definitions § 51.2090 Serious damage. Serious damage means any..., rancidity, insect injury and damage by mold. The following defect shall be considered as serious damage...

  11. 7 CFR 51.2090 - Serious damage.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Standards for Grades of Almonds in the Shell Definitions § 51.2090 Serious damage. Serious damage means any..., rancidity, insect injury and damage by mold. The following defect shall be considered as serious damage...

  12. Radiation damage in macromolecular cryocrystallography.

    PubMed

    Ravelli, Raimond B G; Garman, Elspeth F

    2006-10-01

    X-ray radiation damage to cryocooled ( approximately 100 K) macromolecular crystals has emerged as a general problem, especially since the advent of third generation synchrotron undulator sources. Interest in understanding the physical and chemical phenomena behind the observed effects is growing rapidly. The specific structural damage seen in electron density maps has to be accounted for when studying intermediates, and can sometimes be related to biological function. Radiation damage induces non-isomorphism, thus hampering traditional phasing methods. However, specific damage can also be used to obtain phases. With an increased knowledge of expected crystal lifetime, beamline characteristics and types of damage, macromolecular crystallographers might soon be able to account for radiation damage in data collection, processing and phasing.

  13. Self-Healing Characteristics of Damaged Rock Salt under Different Healing Conditions.

    PubMed

    Chen, Jie; Ren, Song; Yang, Chunhe; Jiang, Deyi; Li, Lin

    2013-08-12

    Salt deposits are commonly regarded as ideal hosts for geologic energy reservoirs. Underground cavern construction-induced damage in salt is reduced by self-healing. Thus, studying the influencing factors on such healing processes is important. This research uses ultrasonic technology to monitor the longitudinal wave velocity variations of stress-damaged rock salts during self-recovery experiments under different recovery conditions. The influences of stress-induced initial damage, temperature, humidity, and oil on the self-recovery of damaged rock salts are analyzed. The wave velocity values of the damaged rock salts increase rapidly during the first 200 h of recovery, and the values gradually increase toward stabilization after 600 h. The recovery of damaged rock salts is subjected to higher initial damage stress. Water is important in damage recovery. The increase in temperature improves damage recovery when water is abundant, but hinders recovery when water evaporates. The presence of residual hydraulic oil blocks the inter-granular role of water and restrains the recovery under triaxial compression. The results indicate that rock salt damage recovery is related to the damage degree, pore pressure, temperature, humidity, and presence of oil due to the sealing integrity of the jacket material.

  14. Self-Healing Characteristics of Damaged Rock Salt under Different Healing Conditions

    PubMed Central

    Chen, Jie; Ren, Song; Yang, Chunhe; Jiang, Deyi; Li, Lin

    2013-01-01

    Salt deposits are commonly regarded as ideal hosts for geologic energy reservoirs. Underground cavern construction-induced damage in salt is reduced by self-healing. Thus, studying the influencing factors on such healing processes is important. This research uses ultrasonic technology to monitor the longitudinal wave velocity variations of stress-damaged rock salts during self-recovery experiments under different recovery conditions. The influences of stress-induced initial damage, temperature, humidity, and oil on the self-recovery of damaged rock salts are analyzed. The wave velocity values of the damaged rock salts increase rapidly during the first 200 h of recovery, and the values gradually increase toward stabilization after 600 h. The recovery of damaged rock salts is subjected to higher initial damage stress. Water is important in damage recovery. The increase in temperature improves damage recovery when water is abundant, but hinders recovery when water evaporates. The presence of residual hydraulic oil blocks the inter-granular role of water and restrains the recovery under triaxial compression. The results indicate that rock salt damage recovery is related to the damage degree, pore pressure, temperature, humidity, and presence of oil due to the sealing integrity of the jacket material. PMID:28811444

  15. Evaluation of residue drum storage safety risks

    SciTech Connect

    Conner, W.V.

    1994-06-17

    A study was conducted to determine if any potential safety problems exist in the residue drum backlog at the Rocky Flats Plant. Plutonium residues stored in 55-gallon drums were packaged for short-term storage until the residues could be processed for plutonium recovery. These residues have now been determined by the Department of Energy to be waste materials, and the residues will remain in storage until plans for disposal of the material can be developed. The packaging configurations which were safe for short-term storage may not be safe for long-term storage. Interviews with Rocky Flats personnel involved with packaging the residues reveal that more than one packaging configuration was used for some of the residues. A tabulation of packaging configurations was developed based on the information obtained from the interviews. A number of potential safety problems were identified during this study, including hydrogen generation from some residues and residue packaging materials, contamination containment loss, metal residue packaging container corrosion, and pyrophoric plutonium compound formation. Risk factors were developed for evaluating the risk potential of the various residue categories, and the residues in storage at Rocky Flats were ranked by risk potential. Preliminary drum head space gas sampling studies have demonstrated the potential for formation of flammable hydrogen-oxygen mixtures in some residue drums.

  16. Impact Damage to Composite Structures

    DTIC Science & Technology

    1986-02-01

    Security Classification of Document UNCLASSIFIED 6. Title IMPACT DAMAGE TO COMPOSITE STRUCTURES 7. Presented at 8. Authar(s)/Editor(s) Various 10...materials Composite structures Structural analysis Mechanical properties Impact strength Damage 14. Abstract The Structures and Materials Panel...POSTGRADUATE SCHOOL MOMTEREY, CAL1F.QRN.IA 9,19ili AGARD-R-729 AGARD REPORT No.729 Impact Damage to Composite Structures * DISTRIBUTION AND AVAILABILITY

  17. The oxidative damage initiation hypothesis for meiosis.

    PubMed

    Hörandl, Elvira; Hadacek, Franz

    2013-12-01

    The maintenance of sexual reproduction in eukaryotes is still a major enigma in evolutionary biology. Meiosis represents the only common feature of sex in all eukaryotic kingdoms, and thus, we regard it a key issue for discussing its function. Almost all asexuality modes maintain meiosis either in a modified form or as an alternative pathway, and facultatively apomictic plants increase frequencies of sexuality relative to apomixis after abiotic stress. On the physiological level, abiotic stress causes oxidative stress. We hypothesize that repair of oxidative damage on nuclear DNA could be a major driving force in the evolution of meiosis. We present a hypothetical model for the possible redox chemistry that underlies the binding of the meiosis-specific protein Spo11 to DNA. During prophase of meiosis I, oxidized sites at the DNA molecule are being targeted by the catalytic tyrosine moieties of Spo11 protein, which acts like an antioxidant reducing the oxidized target. The oxidized tyrosine residues, tyrosyl radicals, attack the phosphodiester bonds of the DNA backbone causing DNA double strand breaks that can be repaired by various mechanisms. Polyploidy in apomictic plants could mitigate oxidative DNA damage and decrease Spo11 activation. Our hypothesis may contribute to explaining various enigmatic phenomena: first, DSB formation outnumbers crossovers and, thus, effective recombination events by far because the target of meiosis may be the removal of oxidative lesions; second, it offers an argument for why expression of sexuality is responsive to stress in many eukaryotes; and third, repair of oxidative DNA damage turns meiosis into an essential characteristic of eukaryotic reproduction.

  18. Isothermal Fatigue, Damage Accumulation, and Life Prediction of a Woven PMC

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, Andrew L.

    1998-01-01

    This dissertation focuses on the characterization of the fully reversed fatigue behavior exhibited by a carbon fiber/polyimide resin, woven laminate at room and elevated temperatures. Nondestructive video edge view microscopy and destructive sectioning techniques were used to study the microscopic damage mechanisms that evolved. The residual elastic stiffness was monitored and recorded throughout the fatigue life of the coupon. In addition, residual compressive strength tests were conducted on fatigue coupons with various degrees of damage as quantified by stiffness reduction. Experimental results indicated that the monotonic tensile properties were only minimally influenced by temperature, while the monotonic compressive and fully reversed fatigue properties displayed noticeable reductions due to the elevated temperature. The stiffness degradation, as a function of cycles, consisted of three stages; a short-lived high degradation period, a constant degradation rate segment composing the majority of the life, and a final stage demonstrating an increasing rate of degradation up to failure. Concerning the residual compressive strength tests at room and elevated temperatures, the elevated temperature coupons appeared much more sensitive to damage. At elevated temperatures, coupons experienced a much larger loss in compressive strength when compared to room temperature coupons with equivalent damage. The fatigue damage accumulation law proposed for the model incorporates a scalar representation for damage, but admits a multiaxial, anisotropic evolutionary law. The model predicts the current damage (as quantified by residual stiffness) and remnant life of a composite that has undergone a known load at temperature. The damage/life model is dependent on the applied multiaxial stress state as well as temperature. Comparisons between the model and data showed good predictive capabilities concerning stiffness degradation and cycles to failure.

  19. Structural damage detection by a new iterative regularization method and an improved sensitivity function

    NASA Astrophysics Data System (ADS)

    Entezami, Alireza; Shariatmadar, Hashem; Sarmadi, Hassan

    2017-07-01

    A new sensitivity-based damage detection method is proposed to identify and estimate the location and severity of structural damage using incomplete noisy modal data. For these purposes, an improved sensitivity function of modal strain energy (MSE) based on Lagrange optimization problem is derived to adapt the initial sensitivity formulation of MSE to damage detection problem with the aid of new mathematical approaches. In the presence of incomplete noisy modal data, the sensitivity matrix is sparse, rectangular, and ill-conditioned, which leads to an ill-posed damage equation. To overcome this issue, a new regularization method named as Regularized Least Squares Minimal Residual (RLSMR) is proposed to solve the ill-posed damage equation. This method relies on Krylov subspace and exploits bidiagonalization and iterative algorithms to solve linear mathematical systems. For the majority of Krylov subspace methods, conventional direct methods for the determination of an optimal regularization parameter may not be proper. To cope with this limitation, a hybrid technique is introduced that depends on the residual of RLSMR method, the number of iterations, and the bidiagonalization algorithm. The accuracy and performance of the improved and proposed methods are numerically examined by a planner truss by incorporating incomplete noisy modal parameters and finite element modeling errors. A comparative study on the initial and improved sensitivity functions is conduced to investigate damage detectability of these sensitivity formulations. Furthermore, the accuracy and robustness of RLSMR method in detecting damage are compared with the well-known Tikhonov regularization method. Results show that the improved sensitivity of MSE is an efficient tool for using in the damage detection problem due to a high sensitivity to damage and reliable damage detectability in comparison with the initial sensitivity function. Additionally, it is observed that the RLSMR method with the aid

  20. Prediction of tissue thermal damage.

    PubMed

    Li, Xin; Zhong, Yongmin; Subic, Aleksandar; Jazar, Reza; Smith, Julian; Gu, Chengfan

    2016-04-29

    This paper presents a method to characterize tissue thermal damage by taking into account the thermal-mechanical effect of soft tissues for thermal ablation. This method integrates the bio-heating conduction and non-rigid motion dynamics to describe thermal-mechanical behaviors of soft tissues and further extends the traditional tissue damage model to characterize thermal-mechanical damage of soft tissues. Simulations and comparison analysis demonstrate that the proposed method can effectively predict tissue thermal damage and it also provides reliable guidelines for control of the thermal ablation procedure.

  1. DNA damage and breast cancer

    PubMed Central

    Davis, Jennifer D; Lin, Shiaw-Yih

    2011-01-01

    Cancer is intimately related to the accumulation of DNA damage, and repair failures (including mutation prone repair and hyperactive repair systems). This article relates current clinical categories for breast cancer and their common DNA damage repair defects. Information is included on the potential for accumulation of DNA damage in the breast tissue of a woman during her lifetime and the role of DNA damage in breast cancer development. We then cover endogenous and exogenous sources of DNA damage, types of DNA damage repair and basic signal transduction pathways for three gene products involved in the DNA damage response system; namely BRCA1, BRIT1 and PARP-1. These genes are often considered tumor suppressors because of their roles in DNA damage response and some are under clinical investigation as likely sources for effective new drugs to treat breast cancers. Finally we discuss some of the problems of DNA damage repair systems in cancer and the conundrum of hyper-active repair systems which can introduce mutations and confer a survival advantage to certain types of cancer cells. PMID:21909479

  2. Dose rate effects on damage formation in ion-implanted gallium arsenide

    SciTech Connect

    Haynes, T.E.; Holland, O.W.

    1990-09-01

    The residual damage in GaAs was measured by ion channeling following implantation of either 100 keV {sup 30}Si{sup +} at temperatures of 300K or 77K, or 360 keV {sup 120}Sn{sup +} at 300K. For room-temperature Si implants and fluences between 1 and 10 {times} 10{sup 14} Si/cm{sup 2}, the amount of damage created was strongly dependent upon the ion current density, which was varied between 0.05 and 12 {mu}A/cm{sup 2}. Two different stages of damage growth were identified by an abrupt increase in the damage growth rate as a function of fluence, and the threshold fluence for the onset of the second stage was found to be dependent on the dose rate. The dose rate effect on damage was substantially weaker for {sup 120}Sn{sup +} implants and was negligible for Si implants at 77K. The damage was found to be most sensitive to the average current density, demonstrating that the defects which are the precursors to the residual dose-rate dependent damage have active lifetimes of at least 3 {times} 10{sup {minus}4} s. The dose rate effect and its variation with ion mass and temperature are discussed in the context of homogeneous nucleation and growth of damage during ion irradiation.

  3. PESTICIDE RESIDUE RECOVERIES FROM SURFACE WIPES

    EPA Science Inventory

    Human exposure is a consequence of pesticide use indoors with a primary source resulting from residue deposition on household surfaces. Accurate measurements of surface residues is essential for estimating exposure from different routes. Various procedures have been developed ...

  4. 48 CFR 970.5001 - Residual powers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Residual powers. 970.5001 Section 970.5001 Federal Acquisition Regulations System DEPARTMENT OF ENERGY AGENCY SUPPLEMENTARY....5001 Residual powers....

  5. 48 CFR 250.104 - Residual powers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Residual powers. 250.104 Section 250.104 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT... Contractual Actions 250.104 Residual powers....

  6. 48 CFR 250.104 - Residual powers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Residual powers. 250.104 Section 250.104 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT... Contractual Actions 250.104 Residual powers....

  7. 48 CFR 970.5001 - Residual powers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Residual powers. 970.5001 Section 970.5001 Federal Acquisition Regulations System DEPARTMENT OF ENERGY AGENCY SUPPLEMENTARY....5001 Residual powers....

  8. 48 CFR 1850.104 - Residual powers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Residual powers. 1850.104 Section 1850.104 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND SPACE ADMINISTRATION... 1850.104 Residual powers....

  9. 48 CFR 250.104 - Residual powers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Residual powers. 250.104 Section 250.104 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT... Contractual Actions 250.104 Residual powers....

  10. 48 CFR 250.104 - Residual powers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Residual powers. 250.104 Section 250.104 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT... Contractual Actions 250.104 Residual powers....

  11. 48 CFR 1850.104 - Residual powers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Residual powers. 1850.104 Section 1850.104 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND SPACE ADMINISTRATION... 1850.104 Residual powers....

  12. 48 CFR 1850.104 - Residual powers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Residual powers. 1850.104 Section 1850.104 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND SPACE ADMINISTRATION... 1850.104 Residual powers....

  13. 48 CFR 970.5001 - Residual powers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Residual powers. 970.5001 Section 970.5001 Federal Acquisition Regulations System DEPARTMENT OF ENERGY AGENCY SUPPLEMENTARY....5001 Residual powers....

  14. 48 CFR 970.5001 - Residual powers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Residual powers. 970.5001 Section 970.5001 Federal Acquisition Regulations System DEPARTMENT OF ENERGY AGENCY SUPPLEMENTARY....5001 Residual powers....

  15. 48 CFR 970.5001 - Residual powers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Residual powers. 970.5001 Section 970.5001 Federal Acquisition Regulations System DEPARTMENT OF ENERGY AGENCY SUPPLEMENTARY....5001 Residual powers....

  16. 48 CFR 250.104 - Residual powers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Residual powers. 250.104 Section 250.104 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT... Contractual Actions 250.104 Residual powers....

  17. Interpretation on Recycling Plastics from Shredder Residue

    EPA Pesticide Factsheets

    EPA is considering an interpretation of its regulations that would generally allow for recycling of plastic separated from shredder residue under the conditions described in the Voluntary Procedures for Recycling Plastics from Shredder Residue.

  18. PESTICIDE RESIDUE RECOVERIES FROM SURFACE WIPES

    EPA Science Inventory

    Human exposure is a consequence of pesticide use indoors with a primary source resulting from residue deposition on household surfaces. Accurate measurements of surface residues is essential for estimating exposure from different routes. Various procedures have been developed ...

  19. Tyrosine-dependent oxidative DNA damage induced by carcinogenic tetranitromethane.

    PubMed

    Murata, Mariko; Kurimoto, Saori; Kawanishi, Shosuke

    2006-10-01

    Tetranitromethane (TNM) is used as an oxidizer in rocket propellants and explosives and as an additive to increase the cetane number of diesel fuel. TNM was reported to induce pulmonary adenocarcinomas and squamous cell carcinomas in mice and rats. However, the mechanisms underlying carcinogenesis induced by TNM has not yet been clarified. We previously revealed that nitroTyr and nitroTyr-containing peptides caused Cu(II)-dependent DNA damage in the presence of P450 reductase, which is considered to yield nitroreduction. Since TNM is a reagent for nitration of Tyr in proteins and peptides, we have hypothesized that TNM-treated Tyr and Tyr-containing peptides induce DNA damage by the modification of Tyr. We examined DNA damage induced by TNM-treated amino acids or peptides using (32)P-5'-end-labeled DNA fragments obtained from the human p53 tumor suppressor gene and the c-Ha-ras-1 protooncogene. TNM-treated Tyr and Lys-Tyr-Lys induced DNA damage including the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine in the presence of Cu(II) and NADH. DNA damage was inhibited by catalase and bathocuproine, indicating the involvement of H(2)O(2) and Cu(I). The cytosine residue of the ACG sequence complementary to codon 273, well-known hotspots of the p53 gene, was cleaved with piperidine and Fpg treatments. On the other hand, nitroTyr and Lys-nitroTyr-Lys did not induce DNA damage in the presence of Cu(II) and NADH. Time-of-flight mass spectrometry confirmed that reactions between Lys-Tyr-Lys and TNM yielded not only Lys-nitroTyr-Lys but also Lys-nitrosoTyr-Lys. Therefore, it is speculated that the nitrosotyrosine residue can induce oxidative DNA damage in the presence of Cu(II) and NADH. It is concluded that Tyr-dependent DNA damage may play an important role in the carcinogenicity of TNM. TNM is a new type of carcinogen that induces DNA damage not by itself but via Tyr modification.

  20. Ribonucleotide triggered DNA damage and RNA-DNA damage responses

    PubMed Central

    Wallace, Bret D; Williams, R Scott

    2014-01-01

    Research indicates that the transient contamination of DNA with ribonucleotides exceeds all other known types of DNA damage combined. The consequences of ribose incorporation into DNA, and the identity of protein factors operating in this RNA-DNA realm to protect genomic integrity from RNA-triggered events are emerging. Left unrepaired, the presence of ribonucleotides in genomic DNA impacts cellular proliferation and is associated with chromosome instability, gross chromosomal rearrangements, mutagenesis, and production of previously unrecognized forms of ribonucleotide-triggered DNA damage. Here, we highlight recent findings on the nature and structure of DNA damage arising from ribonucleotides in DNA, and the identification of cellular factors acting in an RNA-DNA damage response (RDDR) to counter RNA-triggered DNA damage. PMID:25692233

  1. Ribonucleotide triggered DNA damage and RNA-DNA damage responses.

    PubMed

    Wallace, Bret D; Williams, R Scott

    2014-01-01

    Research indicates that the transient contamination of DNA with ribonucleotides exceeds all other known types of DNA damage combined. The consequences of ribose incorporation into DNA, and the identity of protein factors operating in this RNA-DNA realm to protect genomic integrity from RNA-triggered events are emerging. Left unrepaired, the presence of ribonucleotides in genomic DNA impacts cellular proliferation and is associated with chromosome instability, gross chromosomal rearrangements, mutagenesis, and production of previously unrecognized forms of ribonucleotide-triggered DNA damage. Here, we highlight recent findings on the nature and structure of DNA damage arising from ribonucleotides in DNA, and the identification of cellular factors acting in an RNA-DNA damage response (RDDR) to counter RNA-triggered DNA damage.

  2. Road Damage Following Earthquake

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Ground shaking triggered liquefaction in a subsurface layer of water-saturated sand, producing differential lateral and vertical movement in a overlying carapace of unliquified sand and slit, which moved from right to left towards the Pajaro River. This mode of ground failure, termed lateral spreading, is a principal cause of liquefaction-related earthquake damage caused by the Oct. 17, 1989, Loma Prieta earthquake. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: S.D. Ellen, U.S. Geological Survey

  3. Road Damage Following Earthquake

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Ground shaking triggered liquefaction in a subsurface layer of water-saturated sand, producing differential lateral and vertical movement in a overlying carapace of unliquified sand and slit, which moved from right to left towards the Pajaro River. This mode of ground failure, termed lateral spreading, is a principal cause of liquefaction-related earthquake damage caused by the Oct. 17, 1989, Loma Prieta earthquake. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: S.D. Ellen, U.S. Geological Survey

  4. Assessment of damage in vasculitis: expert ratings of damage

    PubMed Central

    Jayne, David; Luqmani, Raashid; Merkel, Peter A.

    2009-01-01

    Objectives. Current measures of damage in vasculitis do not account for the possibility that some forms of damage may exert greater impact than others. As part of an international effort to revise how damage is quantified in vasculitis clinical research, an exercise was performed to measure expert ratings of damage items. Methods. Members of the Vasculitis Clinical Research Consortium and European Vasculitis Study Group were given a list of 129 items of damage related to WG and microscopic polyangiitis (MPA). Participants were asked to rate each item of damage on an integer scale from 0 to 10, where 10 represented the most severe form of damage and 0 indicated ‘no impact’. Results. A multidisciplinary panel of 50 investigators from North America, Europe and Australia–New Zealand participated. The highest median ratings (8–10) were assigned to items of damage associated with malignancy, tissue ischaemia, the central nervous system and cardiopulmonary manifestations. The mean scores ranged from 1.3 to 9.5. The highest s.d.s (⩾2.5) were associated with forms of damage that may benefit from surgical intervention or may not be causally associated with WG or MPA. Lower scores were assigned by nephrologists in comparison with rheumatologists and by Americans in comparison to Europeans, although the difference in median ranks used by these groups was not statistically significant (P > 0.05 for the comparisons). Conclusions. This exercise represents an important step in the development of a weighting system that may increase the utility of damage index scores for the assessment of patients with vasculitis. PMID:19454608

  5. Shock Initiation of Damaged Explosives

    SciTech Connect

    Chidester, S K; Vandersall, K S; Tarver, C M

    2009-10-22

    Explosive and propellant charges are subjected to various mechanical and thermal insults that can increase their sensitivity over the course of their lifetimes. To quantify this effect, shock initiation experiments were performed on mechanically and thermally damaged LX-04 (85% HMX, 15% Viton by weight) and PBX 9502 (95% TATB, 5% Kel-F by weight) to obtain in-situ manganin pressure gauge data and run distances to detonation at various shock pressures. We report the behavior of the HMX-based explosive LX-04 that was damaged mechanically by applying a compressive load of 600 psi for 20,000 cycles, thus creating many small narrow cracks, or by cutting wedge shaped parts that were then loosely reassembled, thus creating a few large cracks. The thermally damaged LX-04 charges were heated to 190 C for long enough for the beta to delta solid - solid phase transition to occur, and then cooled to ambient temperature. Mechanically damaged LX-04 exhibited only slightly increased shock sensitivity, while thermally damaged LX-04 was much more shock sensitive. Similarly, the insensitive explosive PBX 9502 was mechanically damaged using the same two techniques. Since PBX 9502 does not undergo a solid - solid phase transition but does undergo irreversible or 'rachet' growth when thermally cycled, thermal damage to PBX 9502 was induced by this procedure. As for LX-04, the thermally damaged PBX 9502 demonstrated a greater shock sensitivity than mechanically damaged PBX 9502. The Ignition and Growth reactive flow model calculated the increased sensitivities by igniting more damaged LX-04 and PBX 9502 near the shock front based on the measured densities (porosities) of the damaged charges.

  6. 9 CFR 311.39 - Biological residues.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Biological residues. 311.39 Section... Biological residues. Carcasses, organs, or other parts of carcasses of livestock shall be condemned if it is determined that they are adulterated because of the presence of any biological residues. ...

  7. 9 CFR 311.39 - Biological residues.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Biological residues. 311.39 Section... Biological residues. Carcasses, organs, or other parts of carcasses of livestock shall be condemned if it is determined that they are adulterated because of the presence of any biological residues. ...

  8. Polychlorinated Biphenyls (PCB) Residue Effects Database

    EPA Pesticide Factsheets

    The PCB Residue Effects (PCBRes) Database was developed to assist scientists and risk assessors in correlating PCB and dioxin-like compound residues with toxic effects. The purpose is to develop PCB critical residue values for fish, mammals and birds, especially as these relate to aquatic and aquatic-dependent species.

  9. 48 CFR 50.104 - Residual powers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Residual powers. 50.104... EXTRAORDINARY CONTRACTUAL ACTIONS AND THE SAFETY ACT Extraordinary Contractual Actions 50.104 Residual powers. This section prescribes standards and procedures for exercising residual powers under Pub. L....

  10. 48 CFR 50.104 - Residual powers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Residual powers. 50.104... EXTRAORDINARY CONTRACTUAL ACTIONS AND THE SAFETY ACT Extraordinary Contractual Actions 50.104 Residual powers. This section prescribes standards and procedures for exercising residual powers under Pub. L....

  11. 48 CFR 50.104 - Residual powers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Residual powers. 50.104... EXTRAORDINARY CONTRACTUAL ACTIONS AND THE SAFETY ACT Extraordinary Contractual Actions 50.104 Residual powers. This section prescribes standards and procedures for exercising residual powers under Pub. L....

  12. 48 CFR 50.104 - Residual powers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Residual powers. 50.104... EXTRAORDINARY CONTRACTUAL ACTIONS AND THE SAFETY ACT Extraordinary Contractual Actions 50.104 Residual powers. This section prescribes standards and procedures for exercising residual powers under Pub. L....

  13. 48 CFR 50.104 - Residual powers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Residual powers. 50.104... EXTRAORDINARY CONTRACTUAL ACTIONS AND THE SAFETY ACT Extraordinary Contractual Actions 50.104 Residual powers. This section prescribes standards and procedures for exercising residual powers under Pub. L....

  14. Process to recycle shredder residue

    DOEpatents

    Jody, Bassam J.; Daniels, Edward J.; Bonsignore, Patrick V.

    2001-01-01

    A system and process for recycling shredder residue, in which separating any polyurethane foam materials are first separated. Then separate a fines fraction of less than about 1/4 inch leaving a plastics-rich fraction. Thereafter, the plastics rich fraction is sequentially contacted with a series of solvents beginning with one or more of hexane or an alcohol to remove automotive fluids; acetone to remove ABS; one or more of EDC, THF or a ketone having a boiling point of not greater than about 125.degree. C. to remove PVC; and one or more of xylene or toluene to remove polypropylene and polyethylene. The solvents are recovered and recycled.

  15. Cyclophosphamide in diffuse lung damage.

    PubMed

    Musiatowicz, B; Sulkowska, M; Sulik, M; Famulski, W; Dziecioł, J; Sobaniec-Lotowska, M; Baltaziak, M; Arciuch, L; Rółkowski, R; Jabłońska, E

    1997-01-01

    Some cyclophosphamide toxic effects on lung tissue are presented. Cyclophosphamide metabolism, pathogenesis of lung damage and morphological lung tissue changes caused by that agent were characterized. Attention was focused on BAL evaluation as a useful method in the monitoring of lung tissue damage degree.

  16. Modelling Of Residual Stresses Induced By High Speed Milling Process

    SciTech Connect

    Desmaison, Olivier; Mocellin, Katia; Jardin, Nicolas

    2011-05-04

    Maintenance processes used in heavy industries often include high speed milling operations. The reliability of the post-process material state has to be studied. Numerical simulation appears to be a very interesting way to supply an efficient residual stresses (RS) distribution prediction.Because the adiabatic shear band and the serrated chip shaping are features of the austenitic stainless steel high speed machining, a 2D high speed orthogonal cutting model is briefly presented. This finite element model, developed on Forge registered software, is based on data taken from Outeiro and al.'s paper [1]. A new behaviour law fully coupling Johnson-Cook's constitutive law and Latham and Cockcroft's damage model is detailed in this paper. It ensures results that fit those found in literature.Then, the numerical tools used on the 2D model are integrated to a 3D high speed milling model. Residual stresses distribution is analysed, on the surface and into the depth of the material. Various revolutions and passes of the two teeth hemispheric mill on the workpiece are simulated. Thus the sensitivity of the residual stresses generation to the cutting conditions can be discussed. In order to validate the 3D model, a comparison of the cutting forces measured by EDF R and D to those given by numerical simulations is achieved.

  17. Modelling Of Residual Stresses Induced By High Speed Milling Process

    NASA Astrophysics Data System (ADS)

    Desmaison, Olivier; Mocellin, Katia; Jardin, Nicolas

    2011-05-01

    Maintenance processes used in heavy industries often include high speed milling operations. The reliability of the post-process material state has to be studied. Numerical simulation appears to be a very interesting way to supply an efficient residual stresses (RS) distribution prediction. Because the adiabatic shear band and the serrated chip shaping are features of the austenitic stainless steel high speed machining, a 2D high speed orthogonal cutting model is briefly presented. This finite element model, developed on Forge® software, is based on data taken from Outeiro & al.'s paper [1]. A new behaviour law fully coupling Johnson-Cook's constitutive law and Latham and Cockcroft's damage model is detailed in this paper. It ensures results that fit those found in literature. Then, the numerical tools used on the 2D model are integrated to a 3D high speed milling model. Residual stresses distribution is analysed, on the surface and into the depth of the material. Various revolutions and passes of the two teeth hemispheric mill on the workpiece are simulated. Thus the sensitivity of the residual stresses generation to the cutting conditions can be discussed. In order to validate the 3D model, a comparison of the cutting forces measured by EDF R&D to those given by numerical simulations is achieved.

  18. Damage Progression in Bolted Composites

    NASA Technical Reports Server (NTRS)

    Minnetyan, Levon; Chamis, Christos; Gotsis, Pascal K.

    1998-01-01

    Structural durability,damage tolerance,and progressive fracture characteristics of bolted graphite/epoxy composite laminates are evaluated via computational simulation. Constituent material properties and stress and strain limits are scaled up to the structure level to evaluate the overall damage and fracture propagation for bolted composites. Single and double bolted composite specimens with various widths and bolt spacings are evaluated. The effect of bolt spacing is investigated with regard to the structural durability of a bolted joint. Damage initiation, growth, accumulation, and propagation to fracture are included in the simulations. Results show the damage progression sequence and structural fracture resistance during different degradation stages. A procedure is outlined for the use of computational simulation data in the assessment of damage tolerance, determination of sensitive parameters affecting fracture, and interpretation of experimental results with insight for design decisions.

  19. Damage Progression in Bolted Composites

    NASA Technical Reports Server (NTRS)

    Minnetyan, Levon; Chamis, Christos C.; Gotsis, Pascal K.

    1998-01-01

    Structural durability, damage tolerance, and progressive fracture characteristics of bolted graphite/epoxy composite laminates are evaluated via computational simulation. Constituent material properties and stress and strain limits are scaled up to the structure level to evaluate the overall damage and fracture propagation for bolted composites. Single and double bolted composite specimens with various widths and bolt spacings are evaluated. The effect of bolt spacing is investigated with regard to the structural durability of a bolted joint. Damage initiation, growth, accumulation, and propagation to fracture are included in the simulations. Results show the damage progression sequence and structural fracture resistance during different degradation stages. A procedure is outlined for the use of computational simulation data in the assessment of damage tolerance, determination of sensitive parameters affecting fracture, and interpretation of experimental results with insight for design decisions.

  20. [Damage control surgery: a review].

    PubMed

    Camacho Aguilera, José Francisco; Mascareño Jiménez, Sergio

    2013-01-01

    To present a monographic review of the damage control surgery. Consult and literature review (131 references). We analyzed these relevant articles in relation to damage control surgery. From each reference we obtain concepts, data and techniques derivates of damage control surgery. Damage control surgery is a surgical technique that attempts to avoid the triad of coagulopathy,hypothermia and acidosis through application of three phases in patients with multiple lesions. These phases are: Initial laparotomy, stabilization in ICU and definitive surgery. During initial laparotomy efforts are made to controlling the surgical and non surgical bleeding (through packing) and avoid peritoneal contamination. During the stabilization phase the hypothermia, acidosis and coagulopathy are corrected in ICU. In definitive surgery, packing is removed and makes the definitive repair of lesions. For the trauma surgeon is important the knowledge about the concepts related to damage control surgery. This is applicable to multiple trauma patients, and disaster situations like terrorism acts and natural disasters.