WorldWideScience

Sample records for aeroengines surface damage

  1. Machining the Integral Impeller and Blisk of Aero-Engines: A Review of Surface Finishing and Strengthening Technologies

    Science.gov (United States)

    Fu, Youzhi; Gao, Hang; Wang, Xuanping; Guo, Dongming

    2017-05-01

    The integral impeller and blisk of an aero-engine are high performance parts with complex structure and made of difficult-to-cut materials. The blade surfaces of the integral impeller and blisk are functional surfaces for power transmission, and their surface integrity has significant effects on the aerodynamic efficiency and service life of an aero-engine. Thus, it is indispensable to finish and strengthen the blades before use. This paper presents a comprehensive literature review of studies on finishing and strengthening technologies for the impeller and blisk of aero-engines. The review includes independent and integrated finishing and strengthening technologies and discusses advanced rotational abrasive flow machining with back-pressure used for finishing the integral impeller and blisk. A brief assessment of future research problems and directions is also presented.

  2. Surface integrity of GH4169 affected by cantilever finish grinding and the application in aero-engine blades

    Directory of Open Access Journals (Sweden)

    Li Xun

    2015-10-01

    Full Text Available GH4169 is the main material for aero-engine blades and integrated blisks. Because GH4169 has a poor milling performance, the profile precision and surface integrity of blades and integrated blisks are difficult to be met by utilizing the conventional milling process, which directly influence the global performance and reliability of aero-engines. Through grinding experiments on parameters and surface integrity optimization, the helical cantilever grinding process utilizing a 300# CBN RB wheel is presented and applied in finish machining of GH4169 blades. The profile errors of the blade surface are within ±0.01 mm, the roughness is less than 0.4 μm, the residual compressive stresses and the hardening rate are appropriate, there are no phenomena of burr and smearing with the grinding chips, and the leading/trailing edge can be smoothly connected with the suction/pressure surface. All the experimental results indicate that this grinding process is greatly suitable for the profile finish machining of GH4169 blades.

  3. Development in Geared Turbofan Aeroengine

    Science.gov (United States)

    Mohd Tobi, A. L.; Ismail, A. E.

    2016-05-01

    This paper looks into the implementation of epicyclic gear system to the aeroengine in order to increase the efficiency of the engine. The improvement made is in the direction of improving fuel consumption, reduction in pollutant gasses and perceived noise. Introduction of epicyclic gear system is capable to achieve bypass ratio of up to 15:1 with the benefits of weight and noise reduction. Radical new aircraft designs and engine installation are being studied to overcome some of the challenges associated with the future geared turbofan and open-rotor engine.

  4. Impact damage reduction by structured surface geometry

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Fedorov, Vladimir; McGugan, Malcolm

    2018-01-01

    performance was observed for polyurethane-coated fibre composites with structured geometries at the back surfaces. Repeated impacts by rubber balls on the coated side caused damage and delamination of the coating. The laminates with structured back surfaces showed longer durability than those with a flat back...

  5. Flat Surface Damage Detection System (FSDDS)

    Science.gov (United States)

    Williams, Martha; Lewis, Mark; Gibson, Tracy; Lane, John; Medelius, Pedro; Snyder, Sarah; Ciarlariello, Dan; Parks, Steve; Carrejo, Danny; Rojdev, Kristina

    2013-01-01

    The Flat Surface Damage Detection system (FSDDS} is a sensory system that is capable of detecting impact damages to surfaces utilizing a novel sensor system. This system will provide the ability to monitor the integrity of an inflatable habitat during in situ system health monitoring. The system consists of three main custom designed subsystems: the multi-layer sensing panel, the embedded monitoring system, and the graphical user interface (GUI). The GUI LABVIEW software uses a custom developed damage detection algorithm to determine the damage location based on the sequence of broken sensing lines. It estimates the damage size, the maximum depth, and plots the damage location on a graph. Successfully demonstrated as a stand alone technology during 2011 D-RATS. Software modification also allowed for communication with HDU avionics crew display which was demonstrated remotely (KSC to JSC} during 2012 integration testing. Integrated FSDDS system and stand alone multi-panel systems were demonstrated remotely and at JSC, Mission Operations Test using Space Network Research Federation (SNRF} network in 2012. FY13, FSDDS multi-panel integration with JSC and SNRF network Technology can allow for integration with other complementary damage detection systems.

  6. Generic methods for aero-engine exhaust emission prediction

    NARCIS (Netherlands)

    Shakariyants, S.A.

    2008-01-01

    In the thesis, generic methods have been developed for aero-engine combustor performance, combustion chemistry, as well as airplane aerodynamics, airplane and engine performance. These methods specifically aim to support diverse emission prediction studies coupled with airplane and engine

  7. Low surface damage dry etched black silicon

    Science.gov (United States)

    Plakhotnyuk, Maksym M.; Gaudig, Maria; Davidsen, Rasmus Schmidt; Lindhard, Jonas Michael; Hirsch, Jens; Lausch, Dominik; Schmidt, Michael Stenbæk; Stamate, Eugen; Hansen, Ole

    2017-10-01

    Black silicon (bSi) is promising for integration into silicon solar cell fabrication flow due to its excellent light trapping and low reflectance, and a continuously improving passivation. However, intensive ion bombardment during the reactive ion etching used to fabricate bSi induces surface damage that causes significant recombination. Here, we present a process optimization strategy for bSi, where surface damage is reduced and surface passivation is improved while excellent light trapping and low reflectance are maintained. We demonstrate that reduction of the capacitively coupled plasma power, during reactive ion etching at non-cryogenic temperature (-20 °C), preserves the reflectivity below 1% and improves the effective minority carrier lifetime due to reduced ion energy. We investigate the effect of the etching process on the surface morphology, light trapping, reflectance, transmittance, and effective lifetime of bSi. Additional surface passivation using atomic layer deposition of Al2O3 significantly improves the effective lifetime. For n-type wafers, the lifetime reaches 12 ms for polished and 7.5 ms for bSi surfaces. For p-type wafers, the lifetime reaches 800 μs for both polished and bSi surfaces.

  8. Recent trends in superalloys research for critical aero-engine components

    Energy Technology Data Exchange (ETDEWEB)

    Remy, Luc [Mine ParisTech, CNRS UMR 7633, 91 - Evry (France). Centre des Materiaux; Guedou, Jean-Yves [Snecma Safran Group, Moissy-Cramayel (France). Materials and Processes Dept.

    2010-07-01

    This paper is a brief survey of common research activity on superalloys for aero-engines between Snecma and Mines ParisTech Centre des Materiaux during recent years. First in disks applications, the development of new powder metallurgy superalloys is shown. Then grain boundary engineering is investigated in a wrought superalloy. Secondly, design oriented research on single crystals blades is shown: a damage model for low cycle fatigue is used for life prediction when cracks initiated at casting pores. The methodology developed for assessing coating life is illustrated for thermal barrier coating deposited on AMI single crystal superalloy. (orig.)

  9. Arcing and surface damage in DITE

    International Nuclear Information System (INIS)

    Goodall, D.H.J.; McCracken, G.M.

    1977-11-01

    An investigation into the arcing damage on surfaces exposed to plasmas in the DITE tokamak is described. It has been found that arcing occurs on the fixed limiters, on probes inserted into the plasma and on parts of the torus structure. For surfaces parallel to the toroidal field most of the arcs run across the surface orthogonal to the field direction. Observations in the scanning electron microscope show that the arc tracks are formed by a series of melted craters characteristic of cathode arc spots. The amount of metal removed from the surface is consistent with the concentration of metal observed in the plasma. In plasmas with hydrogen gas puffing during the discharge or with injection of low Z impurities, the arc tracks are observed to be much shallower than in normal low density discharges. Several types of surface damage other than arc tracks have also been observed on probes. These phenomena occur less frequently than arcing and appear to be associated with abnormal discharge conditions. (author)

  10. Experimental Technique of Titanium Fire in Aero-engine

    Directory of Open Access Journals (Sweden)

    MI Guangbao

    2016-06-01

    Full Text Available Titanium fire is the typical catastrophic fault in the aero-engine. Aiming at the urgent demand for experimental technique of titanium fire from advanced high thrust-weight ratio aero-engine, the combustion technology and theory of titanium alloy based on friction oxygen concentration method (FOC were systematically studied. The evaluation method of fireproof property and the friction ignition model were built, and the fireproof mechanism was illustrated. By generalizing recent progress in experimental technique of titanium fire from three levels, including evolutionary rule, mechanism and prevention and control technology, the ideas and directions of experimental technique associated with the application research of titanium fire in the future were proposed, namely overall evaluation of fireproof property close to air flow environment of the aero-engine, prediction model of fireproof property and experimental verification of fireproof technique under the air flow environment of aero-engine. It is necessary to establish the prevention system of titanium fire in aero-engine, which contributes to the realization of "full titanium" in compressor and to the increase of high thrust-weight ratio.

  11. Vibration modelling and verifications for whole aero-engine

    Science.gov (United States)

    Chen, G.

    2015-08-01

    In this study, a new rotor-ball-bearing-casing coupling dynamic model for a practical aero-engine is established. In the coupling system, the rotor and casing systems are modelled using the finite element method, support systems are modelled as lumped parameter models, nonlinear factors of ball bearings and faults are included, and four types of supports and connection models are defined to model the complex rotor-support-casing coupling system of the aero-engine. A new numerical integral method that combines the Newmark-β method and the improved Newmark-β method (Zhai method) is used to obtain the system responses. Finally, the new model is verified in three ways: (1) modal experiment based on rotor-ball bearing rig, (2) modal experiment based on rotor-ball-bearing-casing rig, and (3) fault simulations for a certain type of missile turbofan aero-engine vibration. The results show that the proposed model can not only simulate the natural vibration characteristics of the whole aero-engine but also effectively perform nonlinear dynamic simulations of a whole aero-engine with faults.

  12. Shark skin inspired riblet structures as aerodynamically optimized high temperature coatings for blades of aeroengines

    International Nuclear Information System (INIS)

    Büttner, Claudia C; Schulz, Uwe

    2011-01-01

    This paper deals with different structuring methods for high temperature resistant nickel alloys. The ideal structured surface for a possible application on the blades of aeroengines combines high oxidation resistance with low drag in a hot gas flow. The effect of drag reduction due to riblet structured surfaces was originally inspired by shark scales, which have a drag reducing riblet structure. The necessary riblet sizes for effective drag reduction depend on the temperature, pressure and velocity of the flowing medium (gas or liquid). These riblet sizes were calculated for the different sections in an aeroengine. The riblets were successfully produced on a NiCoCrAlY coating by picosecond laser treatment. This method is suitable for larger structures within the range of some tens of micrometers. Furthermore, experiments were performed by depositing different materials through polymer and metal masks via electrodeposition and physical vapor deposition. All fabricated structures were oxidized at 900–1000 °C for up to 100 h to simulate the temperature conditions in an aeroengine. The resulting shape of the riblets was characterized using scanning electron microscopy. The most accurate structures were obtained by using photolithography with a subsequent electrodeposition of nickel. This method is suited for single digit micrometer structures. The reduction of the wall shear stress was measured in an oil channel. The riblet structures prior to oxidation showed a reduction of the wall shear stress of up to 4.9% compared to a normal smooth surface. This proves that the fabricated riblet design can be used as a drag reducing surface

  13. Sensor fault diagnosis of aero-engine based on divided flight status.

    Science.gov (United States)

    Zhao, Zhen; Zhang, Jun; Sun, Yigang; Liu, Zhexu

    2017-11-01

    Fault diagnosis and safety analysis of an aero-engine have attracted more and more attention in modern society, whose safety directly affects the flight safety of an aircraft. In this paper, the problem concerning sensor fault diagnosis is investigated for an aero-engine during the whole flight process. Considering that the aero-engine is always working in different status through the whole flight process, a flight status division-based sensor fault diagnosis method is presented to improve fault diagnosis precision for the aero-engine. First, aero-engine status is partitioned according to normal sensor data during the whole flight process through the clustering algorithm. Based on that, a diagnosis model is built for each status using the principal component analysis algorithm. Finally, the sensors are monitored using the built diagnosis models by identifying the aero-engine status. The simulation result illustrates the effectiveness of the proposed method.

  14. Sensor fault diagnosis of aero-engine based on divided flight status

    Science.gov (United States)

    Zhao, Zhen; Zhang, Jun; Sun, Yigang; Liu, Zhexu

    2017-11-01

    Fault diagnosis and safety analysis of an aero-engine have attracted more and more attention in modern society, whose safety directly affects the flight safety of an aircraft. In this paper, the problem concerning sensor fault diagnosis is investigated for an aero-engine during the whole flight process. Considering that the aero-engine is always working in different status through the whole flight process, a flight status division-based sensor fault diagnosis method is presented to improve fault diagnosis precision for the aero-engine. First, aero-engine status is partitioned according to normal sensor data during the whole flight process through the clustering algorithm. Based on that, a diagnosis model is built for each status using the principal component analysis algorithm. Finally, the sensors are monitored using the built diagnosis models by identifying the aero-engine status. The simulation result illustrates the effectiveness of the proposed method.

  15. Fuselage boundary-layer refraction of fan tones radiated from an installed turbofan aero-engine.

    Science.gov (United States)

    Gaffney, James; McAlpine, Alan; Kingan, Michael J

    2017-03-01

    A distributed source model to predict fan tone noise levels of an installed turbofan aero-engine is extended to include the refraction effects caused by the fuselage boundary layer. The model is a simple representation of an installed turbofan, where fan tones are represented in terms of spinning modes radiated from a semi-infinite circular duct, and the aircraft's fuselage is represented by an infinitely long, rigid cylinder. The distributed source is a disk, formed by integrating infinitesimal volume sources located on the intake duct termination. The cylinder is located adjacent to the disk. There is uniform axial flow, aligned with the axis of the cylinder, everywhere except close to the cylinder where there is a constant thickness boundary layer. The aim is to predict the near-field acoustic pressure, and in particular, to predict the pressure on the cylindrical fuselage which is relevant to assess cabin noise. Thus no far-field approximations are included in the modelling. The effect of the boundary layer is quantified by calculating the area-averaged mean square pressure over the cylinder's surface with and without the boundary layer included in the prediction model. The sound propagation through the boundary layer is calculated by solving the Pridmore-Brown equation. Results from the theoretical method show that the boundary layer has a significant effect on the predicted sound pressure levels on the cylindrical fuselage, owing to sound radiation of fan tones from an installed turbofan aero-engine.

  16. Bacterial Cell Surface Damage Due to Centrifugal Compaction

    NARCIS (Netherlands)

    Peterson, Brandon W.; Sharma, Prashant K.; van der Mei, Henny C.; Busscher, Henk J.

    Centrifugal damage has been known to alter bacterial cell surface properties and interior structures, including DNA. Very few studies exist on bacterial damage caused by centrifugation because of the difficulty in relating centrifugation speed and container geometry to the damage caused. Here, we

  17. Continuum damage mechanics method for fatigue growth of surface cracks

    International Nuclear Information System (INIS)

    Feng Xiqiao; He Shuyan

    1997-01-01

    With the background of leak-before-break (LBB) analysis of pressurized vessels and pipes in nuclear plants, the fatigue growth problem of either circumferential or longitudinal semi-elliptical surface cracks subjected to cyclic loading is studied by using a continuum damage mechanics method. The fatigue damage is described by a scalar damage variable. From the damage evolution equation at the crack tip, a crack growth equation similar to famous Paris' formula is derived, which shows the physical meaning of Paris' formula. Thereby, a continuum damage mechanics approach is developed to analyze the configuration evolution of surface cracks during fatigue growth

  18. Optimization of Aeroengine Shop Visit Decisions Based on Remaining Useful Life and Stochastic Repair Time

    Directory of Open Access Journals (Sweden)

    Jing Cai

    2016-01-01

    Full Text Available Considering the wide application of condition-based maintenance in aeroengine maintenance practice, it becomes possible for aeroengines to carry out their preventive maintenance in just-in-time (JIT manner by reasonably planning their shop visits (SVs. In this study, an approach is proposed to make aeroengine SV decisions following the concept of JIT. Firstly, a state space model (SSM for aeroengine based on exhaust gas temperature margin is developed to predict the remaining useful life (RUL of aeroengine. Secondly, the effect of SV decisions on risk and service level (SL is analyzed, and an optimization of the aeroengine SV decisions based on RUL and stochastic repair time is performed to carry out JIT manner with the requirement of safety and SL. Finally, a case study considering two CFM-56 aeroengines is presented to demonstrate the proposed approach. The results show that predictive accuracy of RUL with SSM is higher than with linear regression, and the process of SV decisions is simple and feasible for airlines to improve the inventory management level of their aeroengines.

  19. Mining-induced surface damage and the study of countermeasures

    International Nuclear Information System (INIS)

    Cui Jixian

    1994-01-01

    Coal constitutes China's major energy resource. The majority of the coal is produced from underground mining operations. Surface subsidence may amount to 80% of the thickness of the seam mined, while the subsided volume is around 60% of the mined volume underground. An area of 20 hectares of land will be affected with each 1 million tons of coal mined, thereby causing severe surface damage. Following a description of the characteristics of surface damages due to underground mining disturbance, this paper elaborates on the damage prediction method, standards applied for evaluating the damages experienced by surface buildings, land reclamation methods in subsided area, measures for reinforcing and protecting buildings in mining-affected areas, and performance of antideformation buildings

  20. Modeling of laser damage initiated by surface contamination

    International Nuclear Information System (INIS)

    Feit, M.D.; Rubenchik, A.M.; Faux, D.R.; Riddle, R.A.; Shapiro, A.; Eder, D.C.; Penetrante, B.M.; Milam, D.; Genin, F.Y.; Kozlowski, M.R.

    1996-11-01

    The authors are engaged in a comprehensive effort to understand and model the initiation and growth of laser damage initiated by surface contaminants. This includes, for example, the initial absorption by the contaminant, heating and plasma generation, pressure and thermal loading of the transparent substrate, and subsequent shockwave propagation, 'splashing' of molten material and possible spallation, optical propagation and scattering, and treatment of material fracture. The integration use of large radiation hydrodynamics codes, optical propagation codes and material strength codes enables a comprehensive view of the damage process The following picture of surface contaminant initiated laser damage is emerging from our simulations

  1. Low surface damage dry etched black silicon

    DEFF Research Database (Denmark)

    Plakhotnyuk, Maksym M.; Gaudig, Maria; Davidsen, Rasmus Schmidt

    2017-01-01

    Black silicon (bSi) is promising for integration into silicon solar cell fabrication flow due to its excellent light trapping and low reflectance, and a continuously improving passivation. However, intensive ion bombardment during the reactive ion etching used to fabricate bSi induces surface dam...

  2. Automated analysis of damages for radiation in plastics surfaces

    International Nuclear Information System (INIS)

    Andrade, C.; Camacho M, E.; Tavera, L.; Balcazar, M.

    1990-02-01

    Analysis of damages done by the radiation in a polymer characterized by optic properties of polished surfaces, of uniformity and chemical resistance that the acrylic; resistant until the 150 centigrade grades of temperature, and with an approximate weight of half of the glass. An objective of this work is the development of a method that analyze in automated form the superficial damages induced by radiation in plastic materials means an images analyst. (Author)

  3. Characterization of the damage produced on different materials surfaces

    International Nuclear Information System (INIS)

    Dellavale Clara, Hector Damian

    2004-01-01

    In the present work the characterization techniques of surfaces ULOI and RIMAPS have been applied on laboratory samples made from aluminium, stainless steel and material based on fiberglass.The resultant surfaces of, chemical etching with corrosive agents Keller and Tucker, mechanic damage from the wear and tear of abrasive paper and sandrubbing with alumina particles, are analyzed to different level of damage.The systematic application of the above mentioned techniques is carried out with the objective of finding information, which allows to characterize the superficial damage, both in its incipient state as in the extreme situation revealed by the presence of etch pits. Important results have been obtained, in the characterization of the incipient stage of the chemical etching, using the curves of the normalized area.In addition, it was possible to verify the capacity of the techniques in the early detection of the preferential directions generated by the etch pits

  4. Damage to underground coal mines caused by surface blasting

    International Nuclear Information System (INIS)

    Fourie, A.B.; Green, R.W.

    1993-01-01

    An investigation of the potential damage to underground coal workings as a result of surface blasting at an opencast coal mine is described. Seismometers were installed in a worked out area of an underground mine, in the eastern Transvaal region of South Africa, and the vibration caused by nearby surface blasting recorded. These measurements were used to derive peak particle velocities. These velocities were correlated with observed damage underground in order to establish the allowable combination of the two blasting parameters of charge mass per relay, and blast-to-gage point distance. An upper limit of 110mm/sec peak particle velocity was found to be sufficient to ensure that the damage to the particular workings under consideration was minimal. It was further found that a cube-root scaling law provided a better fit to the field data than the common square-root law. 11 refs., 6 figs., 5 tabs

  5. The impact of mechanical log surface damage on chip size ...

    African Journals Online (AJOL)

    Mechanised harvesting operations are becoming more prevalent in South Africa with the realisation that motormanual and manual harvesting operations pose significant health and safety risks to workers. The damage inflicted by single-grip harvester feed rollers and delimbing knives on log surfaces during debranching ...

  6. NDE of Damage in Aircraft Flight Control Surfaces

    International Nuclear Information System (INIS)

    Hsu, David K.; Barnard, Daniel J.; Dayal, Vinay

    2007-01-01

    Flight control surfaces on an aircraft, such as ailerons, flaps, spoilers and rudders, are typically adhesively bonded composite or aluminum honeycomb sandwich structures. These components can suffer from damage caused by hail stone, runway debris, or dropped tools during maintenance. On composites, low velocity impact damages can escape visual inspection, whereas on aluminum honeycomb sandwich, budding failure of the honeycomb core may or may not be accompanied by a disbond. This paper reports a study of the damage morphology in such structures and the NDE methods for detecting and characterizing them. Impact damages or overload failures in composite sandwiches with Nomex or fiberglass core tend to be a fracture or crinkle or the honeycomb cell wall located a distance below the facesheet-to-core bondline. The damage in aluminum honeycomb is usually a buckling failure, propagating from the top skin downward. The NDE methods used in this work for mapping out these damages were: air-coupled ultrasonic scan, and imaging by computer aided tap tester. Representative results obtained from the field will be shown

  7. Multi-Dimensional Damage Detection for Surfaces and Structures

    Science.gov (United States)

    Williams, Martha; Lewis, Mark; Roberson, Luke; Medelius, Pedro; Gibson, Tracy; Parks, Steen; Snyder, Sarah

    2013-01-01

    Current designs for inflatable or semi-rigidized structures for habitats and space applications use a multiple-layer construction, alternating thin layers with thicker, stronger layers, which produces a layered composite structure that is much better at resisting damage. Even though such composite structures or layered systems are robust, they can still be susceptible to penetration damage. The ability to detect damage to surfaces of inflatable or semi-rigid habitat structures is of great interest to NASA. Damage caused by impacts of foreign objects such as micrometeorites can rupture the shell of these structures, causing loss of critical hardware and/or the life of the crew. While not all impacts will have a catastrophic result, it will be very important to identify and locate areas of the exterior shell that have been damaged by impacts so that repairs (or other provisions) can be made to reduce the probability of shell wall rupture. This disclosure describes a system that will provide real-time data regarding the health of the inflatable shell or rigidized structures, and information related to the location and depth of impact damage. The innovation described here is a method of determining the size, location, and direction of damage in a multilayered structure. In the multi-dimensional damage detection system, layers of two-dimensional thin film detection layers are used to form a layered composite, with non-detection layers separating the detection layers. The non-detection layers may be either thicker or thinner than the detection layers. The thin-film damage detection layers are thin films of materials with a conductive grid or striped pattern. The conductive pattern may be applied by several methods, including printing, plating, sputtering, photolithography, and etching, and can include as many detection layers that are necessary for the structure construction or to afford the detection detail level required. The damage is detected using a detector or

  8. Laser-based structural sensing and surface damage detection

    Science.gov (United States)

    Guldur, Burcu

    Damage due to age or accumulated damage from hazards on existing structures poses a worldwide problem. In order to evaluate the current status of aging, deteriorating and damaged structures, it is vital to accurately assess the present conditions. It is possible to capture the in situ condition of structures by using laser scanners that create dense three-dimensional point clouds. This research investigates the use of high resolution three-dimensional terrestrial laser scanners with image capturing abilities as tools to capture geometric range data of complex scenes for structural engineering applications. Laser scanning technology is continuously improving, with commonly available scanners now capturing over 1,000,000 texture-mapped points per second with an accuracy of ~2 mm. However, automatically extracting meaningful information from point clouds remains a challenge, and the current state-of-the-art requires significant user interaction. The first objective of this research is to use widely accepted point cloud processing steps such as registration, feature extraction, segmentation, surface fitting and object detection to divide laser scanner data into meaningful object clusters and then apply several damage detection methods to these clusters. This required establishing a process for extracting important information from raw laser-scanned data sets such as the location, orientation and size of objects in a scanned region, and location of damaged regions on a structure. For this purpose, first a methodology for processing range data to identify objects in a scene is presented and then, once the objects from model library are correctly detected and fitted into the captured point cloud, these fitted objects are compared with the as-is point cloud of the investigated object to locate defects on the structure. The algorithms are demonstrated on synthetic scenes and validated on range data collected from test specimens and test-bed bridges. The second objective of

  9. Damages of surface ozone: evidence from agricultural sector in China

    Science.gov (United States)

    Yi, Fujin; McCarl, Bruce A.; Zhou, Xun; Jiang, Fei

    2018-03-01

    This study measures the damages that surface ozone pollution causes within the Chinese agricultural sector under 2014 conditions. It also analyzes the agricultural benefits of ozone reductions. The analysis is done using a partial equilibrium model of China’s agricultural sector. Results indicate that there are substantial, spatially differentiated damages that are greatest in ozone-sensitive crop growing areas with higher ozone concentrations. The estimated damage to China’s agricultural sector range is between CNY 1.6 trillion and 2.2 trillion, which for comparison is about one fifth of 2014 agricultural revenue. When considering concentration reduction we find a 30% ozone reduction yields CNY 678 billion in sectoral benefits. These benefits largely fall to consumers with producers losing as the production gains lead to lower prices.

  10. Fault Diagnosis of Demountable Disk-Drum Aero-Engine Rotor Using Customized Multiwavelet Method

    Directory of Open Access Journals (Sweden)

    Jinglong Chen

    2015-10-01

    Full Text Available The demountable disk-drum aero-engine rotor is an important piece of equipment that greatly impacts the safe operation of aircraft. However, assembly looseness or crack fault has led to several unscheduled breakdowns and serious accidents. Thus, condition monitoring and fault diagnosis technique are required for identifying abnormal conditions. Customized ensemble multiwavelet method for aero-engine rotor condition identification, using measured vibration data, is developed in this paper. First, customized multiwavelet basis function with strong adaptivity is constructed via symmetric multiwavelet lifting scheme. Then vibration signal is processed by customized ensemble multiwavelet transform. Next, normalized information entropy of multiwavelet decomposition coefficients is computed to directly reflect and evaluate the condition. The proposed approach is first applied to fault detection of an experimental aero-engine rotor. Finally, the proposed approach is used in an engineering application, where it successfully identified the crack fault of a demountable disk-drum aero-engine rotor. The results show that the proposed method possesses excellent performance in fault detection of aero-engine rotor. Moreover, the robustness of the multiwavelet method against noise is also tested and verified by simulation and field experiments.

  11. Surface finish and subsurface damage in polycrystalline optical materials

    Science.gov (United States)

    Shafrir, Shai Negev

    We measure and describe surface microstructure and subsurface damage (SSD) induced by microgrinding of hard metals and hard ceramics used in optical applications. We examine grinding of ceramic materials with bonded abrasives, and, specifically, deterministic microgrinding (DMG). DMG, at fixed nominal infeed rate and with bound diamond abrasive tools, is the preferred technique for optical fabrication of ceramic materials. In DMG material removal is by microcracking. DMG provides cost effective high manufacturing rates, while attaining higher strength and performance, i.e., low level of subsurface damage (SSD). A wide range of heterogeneous materials of interest to the optics industry were studied in this work. These materials include: A binderless tungsten carbide, nonmagnetic Ni-based tungsten carbides, magnetic Co-based tungsten carbides, and, in addition, other hard optical ceramics, such as aluminum oxynitride (Al23O27N5/ALON), polycrystalline alumina (Al2O3/PCA), and chemical vapor deposited (CVD) silicon carbide (Si4C/SiC). These materials are all commercially available. We demonstrate that spots taken with magnetorheological finishing (MRF) platforms can be used for estimating SSD depth induced by the grinding process. Surface morphology was characterized using various microscopy techniques, such as: contact interferometer, noncontact white light interferometer, light microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The evolution of surface roughness with the amount of material removed by the MRF process, as measured within the spot deepest point of penetration, can be divided into two stages. In the first stage the induced damaged layer and associated SSD from microgrinding are removed, reaching a low surface roughness value. In the second stage we observe interaction between the MRF process and the material's microstructure as MRF exposes the subsurface without introducing new damage. Line scans taken parallel to the MR

  12. Damage identification in beams by a response surface based technique

    Directory of Open Access Journals (Sweden)

    Teidj S.

    2014-01-01

    Full Text Available In this work, identification of damage in uniform homogeneous metallic beams was considered through the propagation of non dispersive elastic torsional waves. The proposed damage detection procedure consisted of the following sequence. Giving a localized torque excitation, having the form of a short half-sine pulse, the first step was calculating the transient solution of the resulting torsional wave. This torque could be generated in practice by means of asymmetric laser irradiation of the beam surface. Then, a localized defect assumed to be characterized by an abrupt reduction of beam section area with a given height and extent was placed at a known location of the beam. Next, the response in terms of transverse section rotation rate was obtained for a point situated afterwards the defect, where the sensor was positioned. This last could utilize in practice the concept of laser vibrometry. A parametric study has been conducted after that by using a full factorial design of experiments table and numerical simulations based on a finite difference characteristic scheme. This has enabled the derivation of a response surface model that was shown to represent adequately the response of the system in terms of the following factors: defect extent and severity. The final step was performing the inverse problem solution in order to identify the defect characteristics by using measurement.

  13. Hydroxyapatite coating on damaged tooth surfaces by immersion

    International Nuclear Information System (INIS)

    Lim, Byoung-Ki; Ryu, Su-Chak; Sun, Fangfang; Koh, Kwangnak; Han, Dong-Wook; Lee, Jaebeom

    2009-01-01

    Hydroxyapatite (HAp) was coated on scratched areas of a human tooth and HAp disks by the immersion method in a HAp colloidal solution (≤20 μm of average diameter dispersed in DI water). The surface morphologies of the scratched area after immersion for 1-3 months were investigated showing that the damaged surfaces were remarkably recovered. Then, the mechanical property and chemical stability of the HAp coating layers on both specimens were determined via the Vickers hardness test and concentration measurement of extracted Ca 2+ ions, respectively, after strong acidic treatment. The cellular behavior of mouse calvaria-derived pre-osteoblastic cells (MC3T3-E1) was also examined on the HAp layers regenerated on micro-scratched HAp disks for the purpose of their potential applications on maxillofacial bone conservation and reconstruction for prosthetic dentistry, and artificial disk preparation of a vertebral column. The notable loss of Ca 2+ ions under a highly acidic condition was not observed in the layers coated by HAp adsorption, indicating that the coating surface was well adhered with the original surfaces of the respective specimen. Moreover, the HAp adsorption did not adversely affect the adhesion, growth and proliferation of MC3T3-E1 cells on the coated HAp layers for up to 21 days. These results suggest that the HAp coating on the scratched areas of the tooth would be effectively applicable for the development of long-term prevention of micro-cleavage and tooth health supporters to reduce discoloration and further maxillofacial and orthopedic applications.

  14. Surface Damage Mechanism of Monocrystalline Si Under Mechanical Loading

    Science.gov (United States)

    Zhao, Qingliang; Zhang, Quanli; To, Suet; Guo, Bing

    2017-03-01

    Single-point diamond scratching and nanoindentation on monocrystalline silicon wafer were performed to investigate the surface damage mechanism of Si under the contact loading. The results showed that three typical stages of material removal appeared during dynamic scratching, and a chemical reaction of Si with the diamond indenter and oxygen occurred under the high temperature. In addition, the Raman spectra of the various points in the scratching groove indicated that the Si-I to β-Sn structure (Si-II) and the following β-Sn structure (Si-II) to amorphous Si transformation appeared under the rapid loading/unloading condition of the diamond grit, and the volume change induced by the phase transformation resulted in a critical depth (ductile-brittle transition) of cut (˜60 nm ± 15 nm) much lower than the theoretical calculated results (˜387 nm). Moreover, it also led to abnormal load-displacement curves in the nanoindentation tests, resulting in the appearance of elbow and pop-out effects (˜270 nm at 20 s, 50 mN), which were highly dependent on the loading/unloading conditions. In summary, phase transformation of Si promoted surface deformation and fracture under both static and dynamic mechanical loading.

  15. Surface analysis of transition metal oxalates: Damage aspects

    Energy Technology Data Exchange (ETDEWEB)

    Chenakin, S.P., E-mail: chenakin@imp.kiev.ua [Université Libre de Bruxelles (ULB), Chimie-Physique des Matériaux, B-1050 Bruxelles (Belgium); Institute of Metal Physics, Nat. Acad. Sci. of Ukraine, Akad. Vernadsky Blvd. 36, 03680 Kiev (Ukraine); Szukiewicz, R. [Université Libre de Bruxelles (ULB), Chimie-Physique des Matériaux, B-1050 Bruxelles (Belgium); Barbosa, R.; Kruse, N. [Université Libre de Bruxelles (ULB), Chimie-Physique des Matériaux, B-1050 Bruxelles (Belgium); Voiland School of Chemical Engineering and Bioengineering, Washington State University, 155 Wegner Hall, Pullman, WA 99164-6515 (United States)

    2016-05-15

    Highlights: • Gas evolution from the Mn, Co, Ni and Cu oxalate hydrates in vacuum, during exposure to X-rays and after termination of X-ray irradiation is studied. • A comparative study of the damage caused by X-rays in NiC{sub 2}O{sub 4} and CuC{sub 2}O{sub 4} is carried out. • Effect of Ar{sup +} bombardment on the structure and composition of CoC{sub 2}O{sub 4} is studied. - Abstract: The behavior of transition metal oxalates in vacuum, under X-ray irradiation and low-energy Ar{sup +} ion bombardment was studied. A comparative mass-spectrometric analysis was carried out of gas evolution from the surface of Mn, Co, Ni and Cu oxalate hydrates in vacuum, during exposure to X-rays and after termination of X-ray irradiation. The rates of H{sub 2}O and CO{sub 2} liberation from the oxalates were found to be in an inverse correlation with the temperatures of dehydration and decomposition, respectively. X-ray photoelectron spectroscopy (XPS) was employed to study the X-ray induced damage in NiC{sub 2}O{sub 4} and CuC{sub 2}O{sub 4} by measuring the various XP spectral characteristics and surface composition of the oxalates as a function of time of exposure to X-rays. It was shown that Cu oxalate underwent a significantly faster degradation than Ni oxalate and demonstrated a high degree of X-ray induced reduction from the Cu{sup 2+} to the Cu{sup 1+} chemical state. 500 eV Ar{sup +} sputter cleaning of CoC{sub 2}O{sub 4} for 10 min was found to cause a strong transformation of the oxalate structure which manifested itself in an appreciable alteration of the XP core-level and valence band spectra. The analysis of changes in stoichiometry and comparison of XP spectra of bombarded oxalate with respective spectra of a reference carbonate CoCO{sub 3} implied that the bombardment-induced decomposition of CoC{sub 2}O{sub 4} gave rise to the formation of CoO-like and disordered CoCO{sub 3}-like phases.

  16. A GM (1, 1) Markov Chain-Based Aeroengine Performance Degradation Forecast Approach Using Exhaust Gas Temperature

    OpenAIRE

    Zhao, Ning-bo; Yang, Jia-long; Li, Shu-ying; Sun, Yue-wu

    2014-01-01

    Performance degradation forecast technology for quantitatively assessing degradation states of aeroengine using exhaust gas temperature is an important technology in the aeroengine health management. In this paper, a GM (1, 1) Markov chain-based approach is introduced to forecast exhaust gas temperature by taking the advantages of GM (1, 1) model in time series and the advantages of Markov chain model in dealing with highly nonlinear and stochastic data caused by uncertain factors. In this ap...

  17. Laser induced damage threshold on metallic surfaces during laser cleaning

    CSIR Research Space (South Africa)

    Labuschagne, K

    2005-07-01

    Full Text Available laser paint removal. Laser induced damage on 316L stainless steel was studied, with the target subjected to single and multiple pulse irradiations using a Q-switched Nd:YAG, with fluences between 0.15 and 11.8 J/cm2. Several different damage morphologies...

  18. Analytical Redundancy Design for Aeroengine Sensor Fault Diagnostics Based on SROS-ELM

    Directory of Open Access Journals (Sweden)

    Jun Zhou

    2016-01-01

    Full Text Available Analytical redundancy technique is of great importance to guarantee the reliability and safety of aircraft engine system. In this paper, a machine learning based aeroengine sensor analytical redundancy technique is developed and verified through hardware-in-the-loop (HIL simulation. The modified online sequential extreme learning machine, selective updating regularized online sequential extreme learning machine (SROS-ELM, is employed to train the model online and estimate sensor measurements. It selectively updates the output weights of neural networks according to the prediction accuracy and the norm of output weight vector, tackles the problems of singularity and ill-posedness by regularization, and adopts a dual activation function in the hidden nodes combing neural and wavelet theory to enhance prediction capability. The experimental results verify the good generalization performance of SROS-ELM and show that the developed analytical redundancy technique for aeroengine sensor fault diagnosis based on SROS-ELM is effective and feasible.

  19. The apparent effect of sample surface damage on the dielectric parameters of GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Engelbrecht, J.A.A. [Physics Department, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa)], E-mail: Japie.Engelbrecht@nmmu.ac.za; Hashe, N.G. [Physics Department, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Hillie, K.T. [CSIR-NML Laboratory, P.O. Box 395, Pretoria 0001 (South Africa); Claassens, C.H. [Physics Department, University of the Free State, Bloemfontein 9300 (South Africa)

    2007-12-15

    The dielectric and optical parameters determined by infrared reflectance spectroscopy and computer simulation of a set of GaAs substrates of various surface topologies are reported. The influence of surface damage on the parameters is noted.

  20. The apparent effect of sample surface damage on the dielectric parameters of GaAs

    International Nuclear Information System (INIS)

    Engelbrecht, J.A.A.; Hashe, N.G.; Hillie, K.T.; Claassens, C.H.

    2007-01-01

    The dielectric and optical parameters determined by infrared reflectance spectroscopy and computer simulation of a set of GaAs substrates of various surface topologies are reported. The influence of surface damage on the parameters is noted

  1. Simulation and measurement of ferromagnetic impurities in non-magnetic aeroengine turbine disks using fluxgate magnetometers

    OpenAIRE

    Sebastian Hantscher; Ruixin Zhou; Albert Seidl; Johann Hinken; Christian Ziep

    2015-01-01

    In this paper, ferromagnetic impurities in paramagnetic aeroengine turbine disks are investigated. Because such inclusions represent a significant threat in aviation, a detailed analysis is required for impured turbine disks. For this purpose, sensitive fluxgate magnetometers are used. After a premagnetisation, this sensor is able to detect small ferromagnetic particles by recording the variation of the magnetic flux density while the disk rotates below the sensor head. This trajectory create...

  2. The Brief Introduction of Different Laser Diagnostics Methods Used in Aeroengine Combustion Research

    Directory of Open Access Journals (Sweden)

    Fei Xing

    2016-01-01

    Full Text Available Combustion test diagnosis has always been one of the most important technologies for the development of aerospace engineering. The traditional methods of measurement have been unable to meet the requirements of accurate capture of the flow field in the development process of the aeroengine combustor. Therefore, the development of high-precision measurement and diagnostic techniques to meet the needs of the aeroengine combustor design is imperative. Laser diagnostics techniques developed quickly in the past several years. They are used to measure the parameters of the combustion flow field such as velocity, temperature, and components concentration with high space and time resolution and brought no disturbance. Planar laser-induced fluorescence, coherent anti-Stokes Raman scattering, tunable diode laser absorption spectroscopy, and Raman scattering were introduced systemically in this paper. After analysis of their own advantages and disadvantages, the authors considered validated Raman scattering system and Tunable Diode Laser Absorption Tomography are more suitable for research activities on aeroengine combustion systems.

  3. The modal surface interpolation method for damage localization

    Science.gov (United States)

    Pina Limongelli, Maria

    2017-05-01

    The Interpolation Method (IM) has been previously proposed and successfully applied for damage localization in plate like structures. The method is based on the detection of localized reductions of smoothness in the Operational Deformed Shapes (ODSs) of the structure. The IM can be applied to any type of structure provided the ODSs are estimated accurately in the original and in the damaged configurations. If the latter circumstance fails to occur, for example when the structure is subjected to an unknown input(s) or if the structural responses are strongly corrupted by noise, both false and missing alarms occur when the IM is applied to localize a concentrated damage. In order to overcome these drawbacks a modification of the method is herein investigated. An ODS is the deformed shape of a structure subjected to a harmonic excitation: at resonances the ODS are dominated by the relevant mode shapes. The effect of noise at resonance is usually lower with respect to other frequency values hence the relevant ODS are estimated with higher reliability. Several methods have been proposed to reliably estimate modal shapes in case of unknown input. These two circumstances can be exploited to improve the reliability of the IM. In order to reduce or eliminate the drawbacks related to the estimation of the ODSs in case of noisy signals, in this paper is investigated a modified version of the method based on a damage feature calculated considering the interpolation error relevant only to the modal shapes and not to all the operational shapes in the significant frequency range. Herein will be reported the comparison between the results of the IM in its actual version (with the interpolation error calculated summing up the contributions of all the operational shapes) and in the new proposed version (with the estimation of the interpolation error limited to the modal shapes).

  4. Low energy Ar ion bombardment damage of Si, GaAs, and InP surfaces

    International Nuclear Information System (INIS)

    Williams, R.S.

    1982-01-01

    Argon bombardment damage to (100) surfaces of Si, GaAs, and InP for sputter ion-gun potentials of 1, 2, and 3 kilovolts was studied using Rutherford backscattering. Initial damage rates and saturation damage levels were determined. Bombardment damage sensitivity increased for the sequence Si, GaAs, and InP. Saturation damage levels for Si and GaAs correspond reasonably to LSS projected range plus standard deviation estimates; damage to InP exceeded this level significantly. For an ion-gun potential of 3 keV, the initial sputter yield of P from an InP surface exceeded the sputter yield of In by four atoms per incident Ar projectile. (author)

  5. Thermal healing of the sub-surface damage layer in sapphire

    International Nuclear Information System (INIS)

    Pinkas, Malki; Lotem, Haim; Golan, Yuval; Einav, Yeheskel; Golan, Roxana; Chakotay, Elad; Haim, Avivit; Sinai, Ela; Vaknin, Moshe; Hershkovitz, Yasmin; Horowitz, Atara

    2010-01-01

    The sub-surface damage layer formed by mechanical polishing of sapphire is known to reduce the mechanical strength of the processed sapphire and to degrade the performance of sapphire based components. Thermal annealing is one of the methods to eliminate the sub-surface damage layer. This study focuses on the mechanism of thermal healing by studying its effect on surface topography of a- and c-plane surfaces, on the residual stresses in surface layers and on the thickness of the sub-surface damage layer. An atomically flat surface was developed on thermally annealed c-plane surfaces while a faceted roof-top topography was formed on a-plane surfaces. The annealing resulted in an improved crystallographic perfection close to the sample surface as was indicated by a noticeable decrease in X-ray rocking curve peak width. Etching experiments and surface roughness measurements using white light interferometry with sub-nanometer resolution on specimens annealed to different extents indicate that the sub-surface damage layer of the optically polished sapphire is less than 3 μm thick and it is totally healed after thermal treatment at 1450 deg. C for 72 h.

  6. Automated 3D Damaged Cavity Model Builder for Lower Surface Acreage Tile on Orbiter

    Science.gov (United States)

    Belknap, Shannon; Zhang, Michael

    2013-01-01

    The 3D Automated Thermal Tool for Damaged Acreage Tile Math Model builder was developed to perform quickly and accurately 3D thermal analyses on damaged lower surface acreage tiles and structures beneath the damaged locations on a Space Shuttle Orbiter. The 3D model builder created both TRASYS geometric math models (GMMs) and SINDA thermal math models (TMMs) to simulate an idealized damaged cavity in the damaged tile(s). The GMMs are processed in TRASYS to generate radiation conductors between the surfaces in the cavity. The radiation conductors are inserted into the TMMs, which are processed in SINDA to generate temperature histories for all of the nodes on each layer of the TMM. The invention allows a thermal analyst to create quickly and accurately a 3D model of a damaged lower surface tile on the orbiter. The 3D model builder can generate a GMM and the correspond ing TMM in one or two minutes, with the damaged cavity included in the tile material. A separate program creates a configuration file, which would take a couple of minutes to edit. This configuration file is read by the model builder program to determine the location of the damage, the correct tile type, tile thickness, structure thickness, and SIP thickness of the damage, so that the model builder program can build an accurate model at the specified location. Once the models are built, they are processed by the TRASYS and SINDA.

  7. Application of Laser Pulse Heating to Simulate Thermomechanical Damage at Gun Bore Surfaces

    National Research Council Canada - National Science Library

    Cote, Paul

    2003-01-01

    Laser pulse heating experiments were performed to provide insights into the thermomechanical damage effects that occur at the surface of coated and uncoated gun steel under cyclic rapid heating and cooling...

  8. Condition Assessment for Wastewater Pipes: Method for Assessing Cracking and Surface Damage of Concrete Pipes

    OpenAIRE

    Hauge, Petter

    2013-01-01

    The objective of the Master Thesis has been to provide an improved method for condition assessment, which will give a better correlation between Condition class and actual Condition of concrete pipes with cracking and/or surface damages. Additionally improvement of the characterization of cracking (SR) and surface (KO) damages was a sub goal.Based on the findings described in my Thesis and my Specialization Project (Hauge 2012), I recommend that the Norwegian condition assessment method based...

  9. Surface damage in the small intestine of the mouse after X - or neutron irradiation

    International Nuclear Information System (INIS)

    Hamlet, R.; Carr, K.E.; Nias, A.H.; Watt, C.

    1981-01-01

    Damage after X-irradiation includes lateral villous collapse, progressing after 3 - 5 days to villi which sometimes show signs of vertical collapse. After neutron irradiation vertical villous collapse is established earlier, with less swelling of villous tips. It seems, therefore, that at radiobiologically equivalent doses, neutron and X-irradiation produce different levels of surface damage, with neutron irradiation being the more destructive. Early villous tip damage may perhaps be due to disruption of susceptible cells already at the extrusion zone, or to stromal damage

  10. Probability of growth of small damage sites on the exit surface of fused silica optics.

    Science.gov (United States)

    Negres, Raluca A; Abdulla, Ghaleb M; Cross, David A; Liao, Zhi M; Carr, Christopher W

    2012-06-04

    Growth of laser damage on fused silica optical components depends on several key parameters including laser fluence, wavelength, pulse duration, and site size. Here we investigate the growth behavior of small damage sites on the exit surface of SiO₂ optics under exposure to tightly controlled laser pulses. Results demonstrate that the onset of damage growth is not governed by a threshold, but is probabilistic in nature and depends both on the current size of a damage site and the laser fluence to which it is exposed. We also develop models for use in growth prediction. In addition, we show that laser exposure history also influences the behavior of individual sites.

  11. Correlation of DT and DD fusion neutron damage in silicon surface barrier detector

    International Nuclear Information System (INIS)

    Iida, Toshiyuki; Sueyoshi, Yasuhiro; Sunarno; Takahashi, Akito

    1994-01-01

    In order to examine the correlation of DT and DD fusion neutron damage in Si, a silicon surface barrier detector (Si-SBD) was irradiation with neutrons from a deuteron accelerator. The leakage current increased proportionally with neutron fluence, which determined the neutron damage constant for the Si-SBD. The correlation factor of the DT and DD neutron damage in the Si-SBD was determined from the ratio of the DT and DD neutron damage constants and was found to be 2.3. We also calculated the rate of DT and DD neutron displacement damage for Si by using the TRIM-90 computer program and actual data on neutron reactions in the Si-SBD. The correlation factor of DT and DD neutron damage from the calculation agreed with that from the Si-SBD irradiation experiment. (author)

  12. Surface-structure dependence of healing radiation-damage mechanism in nanoporous tungsten

    Science.gov (United States)

    Duan, Guohua; Li, Xiangyan; Sun, Jingjing; Hao, Congyu; Xu, Yichun; Zhang, Yange; Liu, Wei; Liu, C. S.

    2018-01-01

    Under nuclear fusion environments, displacement damage in tungsten (W) is usually caused by neutrons irradiation through producing large quantities of vacancies (Vs) and self-interstitial atoms (SIAs). These defects not only affect the mechanical properties of W, but also act as the trap sites for implanted hydrogen isotopes and helium. Nano-porous (NP) W with a high fraction of free surfaces has been developed to mitigate the radiation damage. However, the mechanism of the surface reducing defects accumulation is not well understood. By using multi-scale simulation methods, we investigated the interaction of the SIA and V with different surfaces on across length and time scales. We found that, at a typical operation temperature of 1000 K, surface (1 1 0) preferentially heals radiation damage of W compared with surface (1 0 0) and boundary (3 1 0). On surface (1 1 0), the diffusion barrier for the SIA is only 0.68 eV. The annihilation of the SIA-V happens via the coupled motion of the V segregation towards the surface from the bulk and the two-dimensional diffusion of the SIA on the surface. Such mechanism makes the surface (1 1 0) owe better healing capability. On surface (1 0 0), the diffusion energy barrier for the SIA is 2.48 eV, higher than the diffusion energy barrier of the V in bulk. The annihilation of the SIA-V occurs via the V segregation and recombination. The SIA was found to migrate one-dimensionally along a boundary (3 1 0) with a barrier of 0.21 eV, leading to a lower healing efficiency in the boundary. This study suggested that the on-surface process plays an important role in healing radiation damage of NP W in addition to surface-enhanced diffusion and annihilation near the surface. A certain surface structure renders nano-structured W more radiation-tolerant.

  13. Manual on the Fatigue of Structures. II. Causes and Prevention of Damage. 7. Mechanical Surface Damage,

    Science.gov (United States)

    1981-06-01

    AO-A103 «29 ADVISORY 6R0UP FOR AEROSPACE RESEARCH AND DEVELOPMENT—ETC F/O 20/11 MANUAL ON THE FATIfUE OF STRUCTURES. IX. CAUSES AND PREVENTION —ETC... stresses . In the case of 99.999% pure aluminium Vyas and Preece240 investigated the changes in the surface finish of the metal under the electron...during the erosion process. In the case of annealed nickel and of electrolytically polished test specimens cavitation- stressed in distilled water at 25°C

  14. Effect of channel aspect ratio on chemical recuperation process in advanced aeroengines

    International Nuclear Information System (INIS)

    Zhang, Silong; Cui, Naigang; Xiong, Yuefei; Feng, Yu; Qin, Jiang; Bao, Wen

    2017-01-01

    The working process of an advanced aeroengine such as scramjet with endothermic hydrocarbon fuel cooling is a chemical recuperative cycle. The design of cooling channel in terms of engine real working conditions is very important for the chemical recuperation process. To study the effects of channel aspect ratio (AR) on chemical recuperation process of advanced aeroengines, three dimensional model of pyrolysis coolant flow inside asymmetrical rectangular cooling channels with fins is introduced and validated through experiments. Cases when AR varies from 1 to 8 are carried out. In the pyrolysis zone of the cooling channel, decreasing the channel aspect ratio can reduce the temperature difference and non-uniformity of fuel conversion in the channel cross section, and it can also increase the final conversion and corresponding chemical heat absorption. A small channel aspect ratio is beneficial for the chemical recuperation process and can guarantee the engine cooling performance in the pyrolysis zone of the cooling channel. - Highlights: • Large non-uniformity of conversion is bad for the chemical recuperation. • Small channel aspect ratio is beneficial for improving the chemical recuperation effectiveness. • Small channel aspect ratio is also beneficial for reducing the engine wall temperature.

  15. The Chaotic Prediction for Aero-Engine Performance Parameters Based on Nonlinear PLS Regression

    Directory of Open Access Journals (Sweden)

    Chunxiao Zhang

    2012-01-01

    Full Text Available The prediction of the aero-engine performance parameters is very important for aero-engine condition monitoring and fault diagnosis. In this paper, the chaotic phase space of engine exhaust temperature (EGT time series which come from actual air-borne ACARS data is reconstructed through selecting some suitable nearby points. The partial least square (PLS based on the cubic spline function or the kernel function transformation is adopted to obtain chaotic predictive function of EGT series. The experiment results indicate that the proposed PLS chaotic prediction algorithm based on biweight kernel function transformation has significant advantage in overcoming multicollinearity of the independent variables and solve the stability of regression model. Our predictive NMSE is 16.5 percent less than that of the traditional linear least squares (OLS method and 10.38 percent less than that of the linear PLS approach. At the same time, the forecast error is less than that of nonlinear PLS algorithm through bootstrap test screening.

  16. Numerical Prediction of the Influence of Thrust Reverser on Aeroengine's Aerodynamic Stability

    Science.gov (United States)

    Zhiqiang, Wang; Xigang, Shen; Jun, Hu; Xiang, Gao; Liping, Liu

    2017-11-01

    A numerical method was developed to predict the aerodynamic stability of a high bypass ratio turbofan engine, at the landing stage of a large transport aircraft, when the thrust reverser was deployed. 3D CFD simulation and 2D aeroengine aerodynamic stability analysis code were performed in this work, the former is to achieve distortion coefficient for the analysis of engine stability. The 3D CFD simulation was divided into two steps, the single engine calculation and the integrated aircraft and engine calculation. Results of the CFD simulation show that with the decreasing of relative wind Mach number, the engine inlet will suffer more severe flow distortion. The total pressure and total temperature distortion coefficients at the inlet of the engines were obtained from the results of the numerical simulation. Then an aeroengine aerodynamic stability analysis program was used to quantitatively analyze the aerodynamic stability of the high bypass ratio turbofan engine. The results of the stability analysis show that the engine can work stably, when the reverser flow is re-ingested. But the anti-distortion ability of the booster is weaker than that of the fan and high pressure compressor. It is a weak link of engine stability.

  17. Research and Development of Some Advanced High Temperature Titanium Alloys for Aero-engine

    Directory of Open Access Journals (Sweden)

    CAI Jian-ming

    2016-08-01

    Full Text Available Some advanced high temperature titanium alloys are usually selected to be manufactured into blade, disc, case, blisk and bling under high temperature environment in compressor and turbine system of a new generation high thrust-mass ratio aero-engine. The latest research progress of 600℃ high temperature titanium alloy, fireproof titanium alloy, TiAl alloy, continuous SiC fiber reinforced titanium matrix composite and their application technology in recent years in China were reviewed in this paper. The key technologies need to be broken through in design, processing and application of new material and component are put forward, including industrial ingot composition of high purified and homogeneous control technology, preparation technology of the large size bar and special forgings, machining technology of blisk and bling parts, material property evaluation and application design technique. The future with the continuous application of advanced high temperature titanium alloys, will be a strong impetus to the development of China's aero-engine technology.

  18. Takagi-Sugeno fuzzy model identification for turbofan aero-engines with guaranteed stability

    Directory of Open Access Journals (Sweden)

    Ruichao LI

    2018-06-01

    Full Text Available This paper is concerned with identifying a Takagi-Sugeno (TS fuzzy model for turbofan aero-engines working under the maximum power status (non-afterburning. To establish the fuzzy system, theoretical contributions are made as follows. First, by fixing antecedent parameters, the estimation of consequent parameters in state-space representations is formulated as minimizing a quadratic cost function. Second, to avoid obtaining unstable identified models, a new theorem is proposed to transform the prior-knowledge of stability into constraints. Then based on the aforementioned work, the identification problem is synthesized as a constrained quadratic optimization. By solving the constrained optimization, a TS fuzzy system is identified with guaranteed stability. Finally, the proposed method is applied to the turbofan aero-engine using simulation data generated from an aerothermodynamics component-level model. Results show the identified fuzzy model achieves a high fitting accuracy while stabilities of the overall fuzzy system and all its local models are also guaranteed. Keywords: Constrained optimization, Fuzzy system, Stability, System identification, Turbofan engine

  19. A Co-modeling Method Based on Component Features for Mechatronic Devices in Aero-engines

    Science.gov (United States)

    Wang, Bin; Zhao, Haocen; Ye, Zhifeng

    2017-08-01

    Data-fused and user-friendly design of aero-engine accessories is required because of their structural complexity and stringent reliability. This paper gives an overview of a typical aero-engine control system and the development process of key mechatronic devices used. Several essential aspects of modeling and simulation in the process are investigated. Considering the limitations of a single theoretic model, feature-based co-modeling methodology is suggested to satisfy the design requirements and compensate for diversity of component sub-models for these devices. As an example, a stepper motor controlled Fuel Metering Unit (FMU) is modeled in view of the component physical features using two different software tools. An interface is suggested to integrate the single discipline models into the synthesized one. Performance simulation of this device using the co-model and parameter optimization for its key components are discussed. Comparison between delivery testing and the simulation shows that the co-model for the FMU has a high accuracy and the absolute superiority over a single model. Together with its compatible interface with the engine mathematical model, the feature-based co-modeling methodology is proven to be an effective technical measure in the development process of the device.

  20. Damage phenomena at target surface by small leak

    International Nuclear Information System (INIS)

    Jeong, Kyung Chai; Jeong, J. Y.; Kim, B. H.; Kim, T. J.; Choi, J. H.

    2001-04-01

    Design of the steam generator should be considered the safety about the sodium-water reaction occurred by water leak in heat transfer tube. Water leak mainly occurred from welding defect at the process of tube connection, the vibration of heat transfer tube bundle in steam generating system, fretting, and pin hole in original tube manufacturing. The classification of water leak divided to two parts, roughly, in case of the water leak studies. One is small leak phenomena analysis, and the other is it of large leak which was mainly treated to the evaluation on pressure increasing from hydrogen gas formed by sodium-water reaction in sodium system. In small water leak, the leak propagation phenomena and the development of leak detecting system at initial stage of small water leak were studied, mainly. In this study, the corrosion phenomena on the target tube surface appeared by sodium-water reaction was analyzed through the small water leak experiments, and, also, the jet phenomena formed by N 2 gas injection through the leak nozzle under water medium was observed

  1. Measurements and TCAD Simulations of Bulk and Surface Radiation Damage Effects

    CERN Document Server

    F. Moscatelli; G. M. Bilei; A. Morozzi; G.-F. Dalla Betta; R. Mendicino; M. Boscardin; N. Zorzi; L. Servoli; P. Maccagnani

    2016-01-01

    In this work we propose the application of a radiation damage model based on the introduction of deep level traps/recombination centers suitable for device level numerical simulation of radiation detectors at very high fluences (e.g. 1÷2×1016 1-MeV equivalent neutrons per square centimeter) combined with a surface damage model developed by using experimental parameters extracted from measurements from gamma irradiated p-type dedicated test structures.

  2. Surface damage of W exposed to combined stationary D plasma and ELMs-like pulsed plasma

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Y.Z., E-mail: jaja880816@aliyun.com [Science and Technology on Reactor Fuel and Materials Laboratory, Nuclear Power Institute of China, Chengdu, Sichuan 610213 (China); Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Liu, W., E-mail: liuw@mail.tsinghua.edu.cn [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Xu, B.; Qu, S.L. [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Morgan, T.W. [FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research, 5612AJ Eindhoven (Netherlands)

    2017-04-15

    The surface damage of W under D plasma and ELMs-like transient heat loads was studied by combined stationary and pulsed D plasma. Low-flux transient heat loads will promote blister formation due to the gas expansion inside the blisters. On the contrary, high-flux transient heat loads will mitigate blistering due to the high surface temperature. Therefore, blistering on W surface first increased and then decreased with the increasing transient heat loads. The promotion effect of pulsed plasma on blistering is more obvious on [001] and [110] surfaces than on [111] surface, and the orientation dependence of blisters was mitigated by the transient heat loads. Surface modification induced by transient heat loads only formed on [001] and [110] surfaces, but did not form on [111] surface. The orientation dependence of surface modification was mainly due to the slipping system of dislocations.

  3. Molecular dynamics simulation of temperature effects on low energy near-surface cascades and surface damage in Cu

    Science.gov (United States)

    Zhu, Guo; Sun, Jiangping; Guo, Xiongxiong; Zou, Xixi; Zhang, Libin; Gan, Zhiyin

    2017-06-01

    The temperature effects on near-surface cascades and surface damage in Cu(0 0 1) surface under 500 eV argon ion bombardment were studied using molecular dynamics (MD) method. In present MD model, substrate system was fully relaxed for 1 ns and a read-restart scheme was introduced to save total computation time. The temperature dependence of damage production was calculated. The evolution of near-surface cascades and spatial distribution of adatoms at varying temperature were analyzed and compared. It was found that near-surface vacancies increased with temperature, which was mainly due to the fact that more atoms initially located in top two layers became adatoms with the decrease of surface binding energy. Moreover, with the increase of temperature, displacement cascades altered from channeling-like structure to branching structure, and the length of collision sequence decreased gradually, because a larger portion of energy of primary knock-on atom (PKA) was scattered out of focused chain. Furthermore, increasing temperature reduced the anisotropy of distribution of adatoms, which can be ascribed to that regular registry of surface lattice atoms was changed with the increase of thermal vibration amplitude of surface atoms.

  4. Molecular dynamics simulation of temperature effects on low energy near-surface cascades and surface damage in Cu

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Guo; Sun, Jiangping; Guo, Xiongxiong; Zou, Xixi; Zhang, Libin; Gan, Zhiyin, E-mail: ganzhiyin@126.com

    2017-06-15

    The temperature effects on near-surface cascades and surface damage in Cu(0 0 1) surface under 500 eV argon ion bombardment were studied using molecular dynamics (MD) method. In present MD model, substrate system was fully relaxed for 1 ns and a read-restart scheme was introduced to save total computation time. The temperature dependence of damage production was calculated. The evolution of near-surface cascades and spatial distribution of adatoms at varying temperature were analyzed and compared. It was found that near-surface vacancies increased with temperature, which was mainly due to the fact that more atoms initially located in top two layers became adatoms with the decrease of surface binding energy. Moreover, with the increase of temperature, displacement cascades altered from channeling-like structure to branching structure, and the length of collision sequence decreased gradually, because a larger portion of energy of primary knock-on atom (PKA) was scattered out of focused chain. Furthermore, increasing temperature reduced the anisotropy of distribution of adatoms, which can be ascribed to that regular registry of surface lattice atoms was changed with the increase of thermal vibration amplitude of surface atoms.

  5. Surface Damage and Treatment by Impact of a Low Temperature Nitrogen Jet

    Science.gov (United States)

    Laribou, Hicham; Fressengeas, Claude; Entemeyer, Denis; Jeanclaude, Véronique; Tazibt, Abdel

    2011-01-01

    Nitrogen jets under high pressure and low temperature have been introduced recently. The process consists in projecting onto a surface a low temperature jet obtained from releasing the liquid nitrogen stored in a high pressure tank (e.g. 3000 bars) through a nozzle. It can be used in a range of industrial applications, including surface treatment or material removal through cutting, drilling, striping and cleaning. The process does not generate waste other than the removed matter, and it only releases neutral gas into the atmosphere. This work is aimed at understanding the mechanisms of the interaction between the jet and the material surface. Depending on the impacted material, the thermo-mechanical shock and blast effect induced by the jet can activate a wide range of damage mechanisms, including cleavage, crack nucleation and spalling, as well as void expansion and localized ductile failure. The test parameters (standoff distance, dwell time, operating pressure) play a role in selecting the dominant damage mechanism, but combinations of these various modes are usually present. Surface treatment through phase transformation or grain fragmentation in a layer below the surface can also be obtained by adequate tuning of the process parameters. In the current study, work is undertaken to map the damage mechanisms in metallic materials as well as the influence of the test parameters on damage, along with measurements of the thermo-mechanical conditions (impact force, temperature) in the impacted area.

  6. Noninvasive assessment of articular cartilage surface damage using reflected polarized light microscopy

    Science.gov (United States)

    Huynh, Ruby N.; Nehmetallah, George; Raub, Christopher B.

    2017-06-01

    Articular surface damage occurs to cartilage during normal aging, osteoarthritis, and in trauma. A noninvasive assessment of cartilage microstructural alterations is useful for studies involving cartilage explants. This study evaluates polarized reflectance microscopy as a tool to assess surface damage to cartilage explants caused by mechanical scraping and enzymatic degradation. Adult bovine articular cartilage explants were scraped, incubated in collagenase, or underwent scrape and collagenase treatments. In an additional experiment, cartilage explants were subject to scrapes at graduated levels of severity. Polarized reflectance parameters were compared with India ink surface staining, features of histological sections, changes in explant wet weight and thickness, and chondrocyte viability. The polarized reflectance signal was sensitive to surface scrape damage and revealed individual scrape features consistent with India ink marks. Following surface treatments, the reflectance contrast parameter was elevated and correlated with image area fraction of India ink. After extensive scraping, polarized reflectance contrast and chondrocyte viability were lower than that from untreated explants. As part of this work, a mathematical model was developed and confirmed the trend in the reflectance signal due to changes in surface scattering and subsurface birefringence. These results demonstrate the effectiveness of polarized reflectance microscopy to sensitively assess surface microstructural alterations in articular cartilage explants.

  7. Switching LPV Control with Double-Layer LPV Model for Aero-Engines

    Science.gov (United States)

    Tang, Lili; Huang, Jinquan; Pan, Muxuan

    2017-11-01

    To cover the whole range of operating conditions of aero-engine, a double-layer LPV model is built so as to take into account of the variability due to the flight altitude, Mach number and the rotational speed. With this framework, the problem of designing LPV state-feedback robust controller that guarantees desired bounds on both H_∞ and H_2 performances is considered. Besides this, to reduce the conservativeness caused by a single LPV controller of the whole flight envelope and the common Lyapunov function method, a new method is proposed to design a family of LPV switching controllers. The switching LPV controllers can ensure that the closed-loop system remains stable in the sense of Lyapunov under arbitrary switching logic. Meanwhile, the switching LPV controllers can ensure the parameters change smoothly. The validity and performance of the theoretical results are demonstrated through a numerical example.

  8. Reliability Estimation of Aero-engine Based on Mixed Weibull Distribution Model

    Science.gov (United States)

    Yuan, Zhongda; Deng, Junxiang; Wang, Dawei

    2018-02-01

    Aero-engine is a complex mechanical electronic system, based on analysis of reliability of mechanical electronic system, Weibull distribution model has an irreplaceable role. Till now, only two-parameter Weibull distribution model and three-parameter Weibull distribution are widely used. Due to diversity of engine failure modes, there is a big error with single Weibull distribution model. By contrast, a variety of engine failure modes can be taken into account with mixed Weibull distribution model, so it is a good statistical analysis model. Except the concept of dynamic weight coefficient, in order to make reliability estimation result more accurately, three-parameter correlation coefficient optimization method is applied to enhance Weibull distribution model, thus precision of mixed distribution reliability model is improved greatly. All of these are advantageous to popularize Weibull distribution model in engineering applications.

  9. Surface damage characteristics of CFC and tungsten with repetitive ELM-like pulsed plasma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Y., E-mail: ykikuchi@eng.u-hyogo.ac.jp [Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, 671-2280 Hyogo (Japan); Nishijima, D. [Center for Energy Research, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0417 (United States); Nakatsuka, M.; Ando, K.; Higashi, T.; Ueno, Y.; Ishihara, M.; Shoda, K.; Nagata, M. [Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, 671-2280 Hyogo (Japan); Kawai, T.; Ueda, Y. [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Fukumoto, N. [Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, 671-2280 Hyogo (Japan); Doerner, R.P. [Center for Energy Research, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0417 (United States)

    2011-08-01

    Surface damage of carbon fiber composite (CFC) and tungsten (W) due to repetitive ELM-like pulsed plasma irradiation has been investigated by using a magnetized coaxial plasma gun. CX2002U CFC and stress-relieved W samples were exposed to repetitive pulsed deuterium plasmas with duration of {approx}0.5 ms, incident ion energy of {approx}30 eV, and surface absorbed energy density of {approx}0.3-0.7 MJ/m{sup 2}. Bright spots on a CFC surface during pulsed plasma exposures were clearly observed with a high-speed camera, indicating a local surface heating. No melting of a W surface was observed under a single plasma pulse exposure at energy density of {approx}0.7 MJ/m{sup 2}, although cracks were formed. Cracking of the W surface grew with repetitive pulsed plasma exposures. Subsequently, the surface melted due to localized heat absorption.

  10. Surface Irregularity Factor as a Parameter to Evaluate the Fatigue Damage State of CFRP

    Science.gov (United States)

    Zuluaga-Ramírez, Pablo; Frövel, Malte; Belenguer, Tomás; Salazar, Félix

    2015-01-01

    This work presents an optical non-contact technique to evaluate the fatigue damage state of CFRP structures measuring the irregularity factor of the surface. This factor includes information about surface topology and can be measured easily on field, by techniques such as optical perfilometers. The surface irregularity factor has been correlated with stiffness degradation, which is a well-accepted parameter for the evaluation of the fatigue damage state of composite materials. Constant amplitude fatigue loads (CAL) and realistic variable amplitude loads (VAL), representative of real in- flight conditions, have been applied to “dog bone” shaped tensile specimens. It has been shown that the measurement of the surface irregularity parameters can be applied to evaluate the damage state of a structure, and that it is independent of the type of fatigue load that has caused the damage. As a result, this measurement technique is applicable for a wide range of inspections of composite material structures, from pressurized tanks with constant amplitude loads, to variable amplitude loaded aeronautical structures such as wings and empennages, up to automotive and other industrial applications. PMID:28793655

  11. Surface Irregularity Factor as a Parameter to Evaluate the Fatigue Damage State of CFRP

    Directory of Open Access Journals (Sweden)

    Pablo Zuluaga-Ramírez

    2015-11-01

    Full Text Available This work presents an optical non-contact technique to evaluate the fatigue damage state of CFRP structures measuring the irregularity factor of the surface. This factor includes information about surface topology and can be measured easily on field, by techniques such as optical perfilometers. The surface irregularity factor has been correlated with stiffness degradation, which is a well-accepted parameter for the evaluation of the fatigue damage state of composite materials. Constant amplitude fatigue loads (CAL and realistic variable amplitude loads (VAL, representative of real in- flight conditions, have been applied to “dog bone” shaped tensile specimens. It has been shown that the measurement of the surface irregularity parameters can be applied to evaluate the damage state of a structure, and that it is independent of the type of fatigue load that has caused the damage. As a result, this measurement technique is applicable for a wide range of inspections of composite material structures, from pressurized tanks with constant amplitude loads, to variable amplitude loaded aeronautical structures such as wings and empennages, up to automotive and other industrial applications.

  12. Advanced Engineering Methods for Assessing Welding Distortion in Aero-Engine Assemblies

    International Nuclear Information System (INIS)

    Jackson, Kathryn; Darlington, Roger

    2011-01-01

    Welding remains an attractive fabrication method for aero-engine assemblies, offering high production rates and reduced total cost, particularly for large complex assemblies. However, distortion generated during the welding process continues to provide a major challenge in terms of the control of geometric tolerances and residual stress. The welding distortion is influenced by the sequence and position of joints, the clamping configuration and the design of the assembly. For large complex assemblies the range of these options may be large. Hence the use of numerical simulation at an early stage of the product development process is valuable to enable a wide range of these factors to be explored with the aim of minimising welding distortions before production commences, and thereby reducing the product development time. In this paper, a new technique for simulation of welding distortions based on a shrinkage analysis is evaluated for an aero-engine assembly. The shrinkage simulations were built and solved using the ESI Group software Weld Planner. The rapid simulation speed enabled a wide range of welding plans to be explored, leading to recommendations for the fabrication process. The sensitivity of the model to mesh size and material properties is reported. The results of the shrinkage analysis were found to be similar to those of a transient analysis generated using ESI Group software SysWeld. The solution times were found to be significantly lower for the shrinkage analysis than the transient analysis. Hence it has been demonstrated that shrinkage analysis is a valuable tool for exploring the fabrication process of a welded assembly at an early stage of the product development process.

  13. The spectral analysis of an aero-engine assembly incorporating a squeeze-film damper

    Science.gov (United States)

    Holmes, R.; Dede, M. M.

    1989-01-01

    Aero-engine structures have very low inherent damping and so artificial damping is often introduced by pumping oil into annular gaps between the casings and the outer races of some or all of the rolling-element bearings supporting the rotors. The thin oil films so formed are called squeeze film dampers and they can be beneficial in reducing rotor vibration due to unbalance and keeping to reasonable limits the forces transmitted to the engine casing. However, squeeze-film dampers are notoriously non-linear and as a result can introduce into the assembly such phenomena as subharmonic oscillations, jumps and combination frequencies. The purpose of the research is to investigate such phenomena both theoretically and experimentally on a test facility reproducing the essential features of a medium-size aero engine. The forerunner of this work was published. It was concerned with the examination of a squeeze-film damper in series with housing flexibility when supporting a rotor. The structure represented to a limited extent the essentials of the projected Rolls Royce RB401 engine. That research demonstrated the ability to calculate the oil-film forces arising from the squeeze film from known motions of the bearing components and showed that the dynamics of a shaft fitted with a squeeze film bearing can be predicted reasonably accurately. An aero-engine will normally have at least two shafts and so in addition to the excitation forces which are synchronous with the rotation of one shaft, there will also be forces at other frequencies from other shafts operating on the squeeze-film damper. Theoretical and experimental work to consider severe loading of squeeze-film dampers and to include these additional effects are examined.

  14. Dry Etch Black Silicon with Low Surface Damage: Effect of Low Capacitively Coupled Plasma Power

    DEFF Research Database (Denmark)

    Iandolo, Beniamino; Plakhotnyuk, Maksym; Gaudig, Maria

    2017-01-01

    Black silicon fabricated by reactive ion etch (RIE) is promising for integration into silicon solar cells thanks to its excellent light trapping ability. However, intensive ion bombardment during the RIE induces surface damage, which results in enhanced surface recombination velocity. Here, we pr...... carrier lifetime thanks to reduced ion energy. Surface passivation using atomic layer deposition of Al2O3 improves the effective lifetime to 7.5 ms and 0.8 ms for black silicon n- and p-type wafers, respectively.......Black silicon fabricated by reactive ion etch (RIE) is promising for integration into silicon solar cells thanks to its excellent light trapping ability. However, intensive ion bombardment during the RIE induces surface damage, which results in enhanced surface recombination velocity. Here, we...... present a RIE optimization leading to reduced surface damage while retaining excellent light trapping and low reflectivity. In particular, we demonstrate that the reduction of the capacitively coupled power during reactive ion etching preserves a reflectance below 1% and improves the effective minority...

  15. Assessment of damage to the desert surfaces of Kuwait due to the Gulf War

    International Nuclear Information System (INIS)

    El-Baz, F.; Al-Ajmi, D.

    1993-01-01

    This is a preliminary report on a joint research project by Boston University and the Kuwait Institute for Scientific Research that commenced in April 1992. The project aim is to establish the extent and nature of environmental damage to the desert surface and coastal zone of Kuwait due to the Gulf War and its aftermath. Change detection image enhancement techniques were employed to enhance environmental change by comparison of Landsat Thematic Mapper images obtained before the wars and after the cessation of the oil and well fires. Higher resolution SPOT images were also utilized to evaluate the nature of the environmental damage to specific areas. The most prominent changes were due to: (1) the deposition of oil and course-grained soot on the desert surface as a result of ''oil rain'' from the plume that emanated from the oil well fires; (2) the formation of hundreds of oil lakes, from oil seepage at the damaged oil well heads; (3) the mobilization of sand and dust and (4) the pollution of segments of the coastal zone by the deposition of oil from several oil spills. Interpretation of satellite image data are checked in the field to confirm the observations, and to assess the nature of the damage. Final results will be utilized in establishing the needs for remedial action to counteract the harmful effects of the various types of damage to the environment of Kuwait

  16. Evaluation of surface fractal dimension of carbon for plasma-facing material damaged by hydrogen plasma

    International Nuclear Information System (INIS)

    Nishino, Nobuhiro

    1997-01-01

    The surface structure of the plasma facing materials (PFM) changes due to plasma-surface interaction in a nuclear fusion reactor. Usually B 4 C coated graphite block are used as PFM. In this report, the surface fractal was applied to study the surface structure of plasma-damaged PFM carbon. A convenient flow-type adsorption apparatus was developed to evaluate the surface fractal dimension of materials. Four branched alkanol molecules with different apparent areas were used as the probe adsorbates. The samples used here were B 4 C coated isotopic graphite which were subjected to hydrogen plasma for various periods of exposure. The monolayer capacities of these samples for alkanols were determined by applying BET theory. The surface fractal dimension was calculated using the monolayer capacities and molecular areas for probe molecules and was found to increase from 2 to 3 with the plasma exposure time. (author)

  17. Bulk and surface laser damage of silica by picosecond and nanosecond pulses at 1064 nm

    International Nuclear Information System (INIS)

    Smith, Arlee V.; Do, Binh T.

    2008-01-01

    We measured bulk and surface dielectric breakdown thresholds of pure silica for 14 ps and 8 ns pulses of 1064 nm light. The thresholds are sharp and reproducible. For the 8 ns pulses the bulk threshold irradiance is 4.75 ± 0.25 kW/μm 2 . The threshold is approximately three times higher for 14 ps pulses. For 8 ns pulses the input surface damage threshold can be made equal to the bulk threshold by applying an alumina or silica surface polish

  18. Experimental study of surface quality and damage when drilling unidirectional CFRP composites

    Directory of Open Access Journals (Sweden)

    Eshetu D. Eneyew

    2014-10-01

    Full Text Available In this study, an experimental investigation on the drilling of unidirectional carbon fiber reinforced plastic (UD-CFRP composite was conducted using polycrystalline diamond (PCD tipped eight facet drill. The quality of the drilled hole surface was examined through surface roughness measurements and surface damage by scanning electron microscopy (SEM. It was found that fiber pullout occurred in two specific sectors relative to the angle between the cutting direction and the fiber orientation. The thrust force was highly influenced by the feed rate than the cutting speed and it shows a significant variation throughout the rotation of the drill.

  19. Application of image based measurement techniques for the investigation of aeroengine performance on a commercial aircraft in ground operation

    OpenAIRE

    Schröder, Andreas; Geisler, Reinhard; Schanz, Daniel; Agocs, Janos; Pallek, Dieter; Schroll, Michael; Klinner, Joachim; Beversdorff, Manfred; Voges, Melanie; Willert, Christian

    2014-01-01

    The investigation of the flow and sound field upstream and downstream of a full scale aeroengine is aimed at providing important reference data required for reliable modeling and prediction. In this regard a wide variety of contactless and non-invasive laser optical and acoustic measurement techniques have matured in recent years to allow their application on full scale aircraft. Within a measurement campaign involving an Airbus A320 DLR research aircraft inside a sound-attenuating hangar at ...

  20. Damage resistance of AR-coated germanium surfaces for nanosecond CO2 laser pulses

    International Nuclear Information System (INIS)

    Newnam, B.E.; Gill, D.H.

    1977-01-01

    An evaluation of the state-of-the-art of AR coatings on gallium-doped germanium, used as a saturable absorber at 10.6 μm, has been conducted. Both 1-on-1 and N-on-1 laser damage thresholds were measured with 1.2 ns pulses on bare and coated surfaces. Only front surface damage was observed. With few exceptions, the thresholds for coated surfaces were centered at 0.49 +- 0.3 J/cm 2 . Bare Ge had a threshold ranging from 0.65 to 0.70 J/cm 2 . No significant differences due to substrate polish, crystallinity or doping level were evident and multiple-shot conditioning resulted in the same threshold as for single shot tests. From an analysis of standing-wave electric fields, damage for AR-coated Ge appeared to be limited by the surface properties of Ge. Measurements at both 1.2 and 70 ns indicated that the threshold (J/cm 2 ) of both coated and uncoated Ge increases as the square root of the pulse-width

  1. Reactive ion beam etching for microcavity surface emitting laser fabrication: technology and damage characterization

    International Nuclear Information System (INIS)

    Matsutani, A.; Tadokoro, T.; Koyama, F.; Iga, K.

    1993-01-01

    Reactive ion beam etching (RIBE) is an effective dry etching technique for the fabrication of micro-sized surface emitting (SE) lasers and optoelectronic devices. In this chapter, some etching characteristics for GaAs, InP and GaInAsP with a Cl 2 gas using an RIBE system are discussed. Micro-sized circular mesas including GaInAsP/InP multilayers with vertical sidewalls were fabricated. RIBE-induced damage in InP substrates was estimated by C-V and PL measurement. In addition, the removal of the induced damage by the second RIBE with different conditions for the InP wafer was proposed. The sidewall damage is characterized by photoluminescence emitted from the etched sidewall of a GaInAsP/InP DH wafer. (orig.)

  2. Surface structural damage associated with longwall mining near Tuscaloosa, Alabama: a case history

    International Nuclear Information System (INIS)

    Isphording, W.C.

    1992-01-01

    Initially the paper examines the frequency of coal mine subsidence and the influence on surface subsidence of subsurface mining methods, i.e. room and pillar and longwall mining. A case study of the subsidence damage caused to a log house near Tuscaloosa, Alabama (USA), when a longwall panel passed beneath it is presented. The damage resulted in the homeowners suing the mining company for negligence. The article discusses information provided to the plaintiffs attorneys by the author. Aspects covered are: the subsidence and damage to the property; prediction of subsidence; the monitoring of subsidence; and the prevention of subsidence. An out-of-court settlement was agreed by the two parties. 15 refs., 5 figs

  3. A GM (1, 1 Markov Chain-Based Aeroengine Performance Degradation Forecast Approach Using Exhaust Gas Temperature

    Directory of Open Access Journals (Sweden)

    Ning-bo Zhao

    2014-01-01

    Full Text Available Performance degradation forecast technology for quantitatively assessing degradation states of aeroengine using exhaust gas temperature is an important technology in the aeroengine health management. In this paper, a GM (1, 1 Markov chain-based approach is introduced to forecast exhaust gas temperature by taking the advantages of GM (1, 1 model in time series and the advantages of Markov chain model in dealing with highly nonlinear and stochastic data caused by uncertain factors. In this approach, firstly, the GM (1, 1 model is used to forecast the trend by using limited data samples. Then, Markov chain model is integrated into GM (1, 1 model in order to enhance the forecast performance, which can solve the influence of random fluctuation data on forecasting accuracy and achieving an accurate estimate of the nonlinear forecast. As an example, the historical monitoring data of exhaust gas temperature from CFM56 aeroengine of China Southern is used to verify the forecast performance of the GM (1, 1 Markov chain model. The results show that the GM (1, 1 Markov chain model is able to forecast exhaust gas temperature accurately, which can effectively reflect the random fluctuation characteristics of exhaust gas temperature changes over time.

  4. Fatigue damage behavior of a surface-mount electronic package under different cyclic applied loads

    Science.gov (United States)

    Ren, Huai-Hui; Wang, Xi-Shu

    2014-04-01

    This paper studies and compares the effects of pull-pull and 3-point bending cyclic loadings on the mechanical fatigue damage behaviors of a solder joint in a surface-mount electronic package. The comparisons are based on experimental investigations using scanning electron microscopy (SEM) in-situ technology and nonlinear finite element modeling, respectively. The compared results indicate that there are different threshold levels of plastic strain for the initial damage of solder joints under two cyclic applied loads; meanwhile, fatigue crack initiation occurs at different locations, and the accumulation of equivalent plastic strain determines the trend and direction of fatigue crack propagation. In addition, simulation results of the fatigue damage process of solder joints considering a constitutive model of damage initiation criteria for ductile materials and damage evolution based on accumulating inelastic hysteresis energy are identical to the experimental results. The actual fatigue life of the solder joint is almost the same and demonstrates that the FE modeling used in this study can provide an accurate prediction of solder joint fatigue failure.

  5. Surface damage through grazing incidence ions investigated by scanning tunneling microscopy

    International Nuclear Information System (INIS)

    Redinger, Alex

    2009-01-01

    Surface damage, caused by grazing incidence ions, is investigated with variable temperature scanning tunneling microscopy. The experiments are carried out on a Pt(111) crystal. The kinetic energy of noble gas ions is varied between 1-15 keV and the angle of incidence can be adjusted between θ = 78.5 and θ = 90 measured with respect to the surface normal. The damage patterns of single ion impacts, on flat terraces and at step edges of monoatomic height, are investigated at low surface temperatures. Ions hitting a flat terrace are usually specular reflected. The energy transfer from the ion to the crystal atoms is small and only little damage is produced. In contrast, at ascending step edges, which are illuminated by the ion beam, large angle scattering events occur. Sputtering, adatom and vacancy production is induced. However, a significant fraction of the ions, which hit step edges, enter the crystal and are guided in between two atomic layers parallel to the surface via small angle binary collisions. This steering process is denoted as subsurface channeling. The energy loss per length scale of the channeled particles is low, which results in long ion trajectories (up to 1000A). During the steering process, the ions produce surface damage. Depending on the ion species and the ion energy, adatom and vacancies or surface vacancy trenches of monoatomic width are observed. The surface damage can be used to track the path of the ion. This makes the whole trajectory of single ions with keV energy visible. The number of sputtered atoms per incident ion at ascending step edges, i.e. the step edge sputtering yield, is measured experimentally for different irradiation conditions. For θ = 86 , the sputtering yield is determined from the fluence dependent retraction of pre-existing illuminated step edges. An alternative method for the step edge sputtering yield determination, is the analysis of the concentration of ascending steps and of the removed amount of material as a

  6. Surface damage through grazing incidence ions investigated by scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Redinger, Alex

    2009-07-10

    Surface damage, caused by grazing incidence ions, is investigated with variable temperature scanning tunneling microscopy. The experiments are carried out on a Pt(111) crystal. The kinetic energy of noble gas ions is varied between 1-15 keV and the angle of incidence can be adjusted between {theta} = 78.5 and {theta} = 90 measured with respect to the surface normal. The damage patterns of single ion impacts, on flat terraces and at step edges of monoatomic height, are investigated at low surface temperatures. Ions hitting a flat terrace are usually specular reflected. The energy transfer from the ion to the crystal atoms is small and only little damage is produced. In contrast, at ascending step edges, which are illuminated by the ion beam, large angle scattering events occur. Sputtering, adatom and vacancy production is induced. However, a significant fraction of the ions, which hit step edges, enter the crystal and are guided in between two atomic layers parallel to the surface via small angle binary collisions. This steering process is denoted as subsurface channeling. The energy loss per length scale of the channeled particles is low, which results in long ion trajectories (up to 1000A). During the steering process, the ions produce surface damage. Depending on the ion species and the ion energy, adatom and vacancies or surface vacancy trenches of monoatomic width are observed. The surface damage can be used to track the path of the ion. This makes the whole trajectory of single ions with keV energy visible. The number of sputtered atoms per incident ion at ascending step edges, i.e. the step edge sputtering yield, is measured experimentally for different irradiation conditions. For {theta} = 86 , the sputtering yield is determined from the fluence dependent retraction of pre-existing illuminated step edges. An alternative method for the step edge sputtering yield determination, is the analysis of the concentration of ascending steps and of the removed amount

  7. Surface damage characterization of FBK devices for High Luminosity LHC (HL-LHC) operations

    Science.gov (United States)

    Moscatelli, F.; Passeri, D.; Morozzi, A.; Dalla Betta, G.-F.; Mattiazzo, S.; Bomben, M.; Bilei, G. M.

    2017-12-01

    The very high fluences (e.g. up to 2×1016 1 MeV neq/cm2) and total ionising doses (TID) of the order of 1 Grad, expected at the High Luminosity LHC (HL-LHC), impose new challenges for the design of effective, radiation resistant detectors. Ionising energy loss is the dominant effect for what concerns SiO2 and SiO2/Si interface radiation damage. In particular, surface damage can create a positive charge layer near the SiO2/Si interface and interface traps along the SiO2/Si interface, which strongly influence the breakdown voltage, the inter-electrode isolation and capacitance, and might also impact the charge collection properties of silicon sensors. To better understand in a comprehensive framework the complex and articulated phenomena related to surface damage at these very high doses, measurements on test structures have been carried out in this work (e.g. C-V and I-V). In particular, we have studied the properties of the SiO2 layer and of the SiO2/Si interface, using MOS capacitors, gated diodes (GD) and MOSFETs manufactured by FBK on high-resistivity n-type and p-type silicon, before and after irradiation with X-rays in the range from 50 krad(SiO2) to 20 Mrad(SiO2). Relevant parameters have been determined for all the tested devices, converging in the oxide charge density NOX, the surface generation velocity s0 and the integrated interface-trap density NIT dose-dependent values. These parameters have been extracted to both characterize the technology as a function of the dose and to be used in TCAD simulations for the surface damage effect modeling and the analysis and optimization of different classes of detectors for the next HEP experiments.

  8. Damage Mechanism in Counter Pairs Caused by Bionic Non-smoothed Surface

    Directory of Open Access Journals (Sweden)

    ZHANG Zhan-hui

    2016-08-01

    Full Text Available Four biomimetic non-smoothed surface specimens with different shapes were prepared by laser processing. Tests were conducted on MMU-5G wear and abrasion test machine to study the influencing rule of non-smoothed surfaces on counter pairs. The results show that the mass loss of the friction pair matching with the non-smoothed units is much greater than the ones matching with the smooth specimens. The pairs matching with different non-smoothed units suffer differently. The non-smoothed surface protruding zone exerts micro cutting on counter pairs. The striation causes the greatest mass loss of the pairs than the other non-smoothed units, which almost doubles the damage of the grid ones suffering the least. The difference in pairs damage is attributed to the different mechanism of undertaking the load in the process of wear. The damage can be alleviated effectively by changing the shapes of the units without increasing or decreasing the area ratio of the non-smoothed units.

  9. The Influence of Ballistic Damage on the Aeroelastic Characteristics of Lifting Surfaces.

    Science.gov (United States)

    1979-07-01

    tunnel wall was sealed with a flexible rubber gasket. The pressure measurements were made using Scanivalve pressure multiplexers and DRUCK pressure...discharge, having a 1.52 by 2.13 m (5 x 7 ft) test section. The drive system comprises four fans of 200 hp each, DRUCK model PDCR differential pressure...3, 4, 5, 6, 8, 9 Surface # IC LS 1 3 2 2 4 2 3 2 2 4 3 2 5 4 2 6 2 2 7 3 3 8 4 3 9 2 3 Damaged - Cases: ID, 2D, 3D , 4D, 5D, 6D, 8D, 9D 1 .Surface # IC

  10. Laser-induced damage of fused silica at 355 and 1065 nm initiated at aluminum contamination particles on the surface

    International Nuclear Information System (INIS)

    Genin, F.Y.; Michlitsch, K.; Furr, J.; Kozlowski, M.R.; Krulevitch, P.

    1997-01-01

    1-μm thick circular dots, 10-250 μm dia, were deposited onto 1.14 cm thick fused silica windows by sputtering Al through a mask. Al shavings were also deposited on the windows to investigate effects of particle-substrate adhesion. The silica windows were then illuminated repetitively using a 3-ns, 355 nm and an 8.6-ns, 1064 nm laser. The tests were conducted at near normal incidence with particles on input and output surfaces of the windows. During the first shot, a plasma ignited at the metal particle and damage initiated on the fused silica surface. The morphology of the damage at the metal dots were reproducible but different for input and output surface contamination. For input surface contamination, minor damage occurred where the particle was located; such damage ceased to grow with the removal of contaminant material. More serious damage (pits and cracks) was initiated on the output surface (especially at 355 nm) and grew to catastrophic proportions after few shots. Output surface contaminants were usually ejected on the initial shot, leaving a wave pattern on the surface. No further damage occurred with subsequent shots unless a shot (usually the first shot) cracked the surface; such behavior was mostly observed at 355 nm and occasionally for large shavings at 1064 nm. The size of the damaged area scaled with the size of the particle (except when catastrophic damage occurred). Onset of catastrophic damage on output surface occurred only when particles exceeded a critical size. Damage behavior of the sputtered dots was found to be qualitatively similar to that of the shavings. The artificial contamination technique accelerated the study by allowing better control of the test conditions

  11. Accumulated surface damage on ZnS crystals produced by closely spaced pairs of picosecond laser pulses

    International Nuclear Information System (INIS)

    Chase, L.L.; Lee, H.W.H.

    1988-12-01

    Excitation of a transparent ZnS crystal by repetitive picosecond dye laser pulses causes an accumulated surface modification leading to optical damage. The onset of the damage is detected by an abrupt increase in the emission of neutral Zn (and possibly S 2 ) from the surface. Comparison of the neutral emission thresholds with pulse-pair and single-pulse excitation shows that linear absorption is the dominant laser-surface interaction. In general, this measurement technique shows considerable promise for investigating the possible influence of nonlinear absorption or excitation processes on damage mechanisms. The data suggest that heating of small absorbing regions produces the surface modification that leads to the observed surface ablation. The nature of the damage observed at fluences above the threshold suggests that it is caused by heating of a relatively large (/approximately/10 - 100 μm) surface region that has been modified by the accumulation pulses. 3 refs., 5 figs

  12. Effect of electrical discharge machining on surface characteristics and machining damage of AISI D2 tool steel

    International Nuclear Information System (INIS)

    Guu, Y.H.; Hocheng, H.; Chou, C.Y.; Deng, C.S.

    2003-01-01

    In this work the electrical discharge machining (EDM) of AISI D2 tool steel was investigated. The surface characteristics and machining damage caused by EDM were studied in terms of machining parameters. Based on the experimental data, an empirical model of the tool steel was also proposed. A new damage variable was used to study the EDM damage. The workpiece surface and re-solidified layers were examined by a scanning electron microscopy. Surface roughness was determined with a surface profilometer. The residual stress acting on the EDM specimen was measured by the X-ray diffraction technique. Experimental results indicate that the thickness of the recast layer, and surface roughness are proportional to the power input. The EDM process introduces tensile residual stress on the machined surface. The EDM damage leads to strength degradation

  13. Roughness, surface energy, and superficial damages of CAD/CAM materials after surface treatment.

    Science.gov (United States)

    Strasser, Thomas; Preis, Verena; Behr, Michael; Rosentritt, Martin

    2018-02-05

    The aim of this study was to examine the effects of surface pre-treatment on CAD/CAM materials including ceramics, zirconia, resin-infiltrated ceramic, and resin-based composite. Specimens were made of ten CAD/CAM materials (Celtra Duo, Degudent, D; Vita Suprinity, Vita, D; E.max CAD, Ivoclar-Vivadent, FL; E.max ZirCAD, Ivoclar-Vivadent, FL; Vita Enamic, Vita, D; Cerasmart, GC, B; LAVA Ultimate, 3M, D; SHOFU Block HC, SHOFU, US; Grandio Blocs, VOCO, D; BRILLIANT Crios, Coltene, CH) and pretreated to represent clinical procedures (Hf 20 s/5%; phosphoric acid 20 s/37%; Monobond etch and prime (Ivoclar-Vivadent, FL); water-cooled diamond bur (80 μm; 4 μm); Al 2 O 3 -blasting (50 μm/1 bar, 50 μm/2 bar, 120 μm/1 bar, 120 μm/2 bar); untreated; manufacturer's instructions). SEM-analysis (Phenom, FEI, NL) of the surfaces was performed (magnifications ≤ 10,000×). Roughness values R a , R z (KJ 3D, Keyence, J), and surface energy SE (OCA15 plus, SCA20, DataPhysics, D) were determined (statistics: non-parametric Mann-Whitney U test/Kruskal-Wallis test for independent specimen, α = 0.05). Kruskal-Wallis revealed significant (p CAD/CAM materials require individual pre-treatment for optimized and protective surface activation. Cementation is a key factor for clinical success. Given the variety of available CAD/CAM materials, specific procedures are needed.

  14. Surface damage of TFTR protective plate candidate materials by energetic D+ irradiation

    International Nuclear Information System (INIS)

    Kaminsky, M.; Das, S.K.

    1979-01-01

    Experiments were conducted to determine the surface damage of ATJ graphite, V, Cu, and Type 316 stainless steel under 60-keV D + irradiation. The irradiations were conducted in the pulsed mode. For a total accumulated dose of 8.1 x 10 18 ions/cm 2 , blisters were readily seen for Cu surfaces, but no blisters were observed on Type 316 stainless steel and vanadium surfaces. For the case of ATJ graphite, the surface damage was observed in the form of ridges and grooves. In the case of copper, many large blisters with diameters ranging from 3.5 μm to 46 μm are observed in addition to some small ones (average diameter approx. 2 μm. The blister density of the large blisters is the highest in the case of copper (1.1 x 10 5 blisters/cm 2 ). These observations of blister formation are related to the differences in the premeability of deuterium in these materials. An examination of the cross section of the ridges in fractured samples of graphite indicates that they are not hollow. The mechanisms of formation of these ridges is not clear at present. 1 figure

  15. High-flux He+ irradiation effects on surface damages of tungsten under ITER relevant conditions

    International Nuclear Information System (INIS)

    Liu, Lu; Liu, Dongping; Hong, Yi; Fan, Hongyu; Ni, Weiyuan; Yang, Qi; Bi, Zhenhua; Benstetter, Günther; Li, Shouzhe

    2016-01-01

    A large-power inductively coupled plasma source was designed to perform the continuous helium ions (He + ) irradiations of polycrystalline tungsten (W) under International Thermonuclear Experimental Reactor (ITER) relevant conditions. He + irradiations were performed at He + fluxes of 2.3 × 10 21 –1.6 × 10 22 /m 2  s and He + energies of 12–220 eV. Surface damages and microstructures of irradiated W were observed by scanning electron microscopy. This study showed the growth of nano-fuzzes with their lengths of 1.3–2.0 μm at He + energies of >70 eV or He + fluxes of >1.3 × 10 22 /m 2  s. Nanometer-sized defects or columnar microstructures were formed in W surface layer due to low-energy He + irradiations at an elevated temperature (>1300 K). The diffusion and coalescence of He atoms in W surface layers led to the growth and structures of nano-fuzzes. This study indicated that a reduction of He + energy below 12–30 eV may greatly decrease the surface damage of tungsten diverter in the fusion reactor.

  16. Quantitative evaluation for small surface damage based on iterative difference and triangulation of 3D point cloud

    Science.gov (United States)

    Zhang, Yuyan; Guo, Quanli; Wang, Zhenchun; Yang, Degong

    2018-03-01

    This paper proposes a non-contact, non-destructive evaluation method for the surface damage of high-speed sliding electrical contact rails. The proposed method establishes a model of damage identification and calculation. A laser scanning system is built to obtain the 3D point cloud data of the rail surface. In order to extract the damage region of the rail surface, the 3D point cloud data are processed using iterative difference, nearest neighbours search and a data registration algorithm. The curvature of the point cloud data in the damage region is mapped to RGB color information, which can directly reflect the change trend of the curvature of the point cloud data in the damage region. The extracted damage region is divided into three prism elements by a method of triangulation. The volume and mass of a single element are calculated by the method of geometric segmentation. Finally, the total volume and mass of the damage region are obtained by the principle of superposition. The proposed method is applied to several typical injuries and the results are discussed. The experimental results show that the algorithm can identify damage shapes and calculate damage mass with milligram precision, which are useful for evaluating the damage in a further research stage.

  17. Process induced sub-surface damage in mechanically ground silicon wafers

    International Nuclear Information System (INIS)

    Yang Yu; De Munck, Koen; Teixeira, Ricardo Cotrin; Swinnen, Bart; De Wolf, Ingrid; Verlinden, Bert

    2008-01-01

    Micro-Raman spectroscopy, scanning electron microcopy, atomic force microscopy and preferential etching were used to characterize the sub-surface damage induced by the rough and fine grinding steps used to make ultra-thin silicon wafers. The roughly and ultra-finely ground silicon wafers were examined on both the machined (1 0 0) planes and the cross-sectional (1 1 0) planes. They reveal similar multi-layer damage structures, consisting of amorphous, plastically deformed and elastically stressed layers. However, the thickness of each layer in the roughly ground sample is much higher than its counterpart layers in the ultra-finely ground sample. The residual stress after rough and ultra-fine grinding is in the range of several hundreds MPa and 30 MPa, respectively. In each case, the top amorphous layer is believed to be the result of sequential phase transformations (Si-I to Si-II to amorphous Si). These phase transformations correspond to a ductile grinding mechanism, which is dominating in ultra-fine grinding. On the other hand, in rough grinding, a mixed mechanism of ductile and brittle grinding causes multi-layer damage and sub-surface cracks

  18. Type of Ground Surface during Plyometric Training Affects the Severity of Exercise-Induced Muscle Damage

    Directory of Open Access Journals (Sweden)

    Hamid Arazi

    2016-03-01

    Full Text Available The purpose of this study was to compare the changes in the symptoms of exercise-induced muscle damage from a bout of plyometric exercise (PE; 10 × 10 vertical jumps performed in aquatic, sand and firm conditions. Twenty-four healthy college-aged men were randomly assigned to one of three groups: Aquatic (AG, n = 8, Sand (SG, n = 8 and Firm (FG, n = 8. The AG performed PE in an aquatic setting with a depth of ~130 cm. The SG performed PE on a dry sand surface at a depth of 20 cm, and the FG performed PE on a 10-cm-thick wooden surface. Plasma creatine kinase (CK activity, delayed onset muscle soreness (DOMS, knee range of motion (KROM, maximal isometric voluntary contraction (MIVC of the knee extensors, vertical jump (VJ and 10-m sprint were measured before and 24, 48 and 72 h after the PE. Compared to baseline values, FG showed significantly (p < 0.05 greater changes in CK, DOMS, and VJ at 24 until 48 h. The MIVC decreased significantly for the SG and FG at 24 until 48 h post-exercise in comparison to the pre-exercise values. There were no significant (p > 0.05 time or group by time interactions in KROM. In the 10-m sprint, all the treatment groups showed significant (p < 0.05 changes compared to pre-exercise values at 24 h, and there were no significant (p > 0.05 differences between groups. The results indicate that PE in an aquatic setting and on a sand surface induces less muscle damage than on a firm surface. Therefore, training in aquatic conditions and on sand may be beneficial for the improvement of performance, with a concurrently lower risk of muscle damage and soreness.

  19. Dynamic behavior of aero-engine rotor with fusing design suffering blade off

    Directory of Open Access Journals (Sweden)

    Cun WANG

    2017-06-01

    Full Text Available Fan blade off (FBO from a running turbofan rotor will introduce sudden unbalance into the dynamical system, which will lead to the rub-impact, the asymmetry of rotor and a series of interesting dynamic behavior. The paper first presents a theoretical study on the response excited by sudden unbalance. The results reveal that the reaction force of the bearing located near the fan could always reach a very high value which may lead to the crush of ball, journal sticking, high stress on the other components and some other failures to endanger the safety of engine in FBO event. Therefore, the dynamic influence of a safety design named “fusing” is investigated by mechanism analysis. Meantime, an explicit FBO model is established to simulate the FBO event, and evaluate the effectiveness and potential dynamic influence of fusing design. The results show that the fusing design could reduce the vibration amplitude of rotor, the reaction force on most bearings and loads on mounts, but the sudden change of support stiffness induced by fusing could produce an impact effect which will couple with the influence of sudden unbalance. Therefore, the implementation of the design should be considered carefully with optimized parameters in actual aero-engine.

  20. Apparatus and method for atmospheric pressure reactive atom plasma processing for shaping of damage free surfaces

    Science.gov (United States)

    Carr,; Jeffrey, W [Livermore, CA

    2009-03-31

    Fabrication apparatus and methods are disclosed for shaping and finishing difficult materials with no subsurface damage. The apparatus and methods use an atmospheric pressure mixed gas plasma discharge as a sub-aperture polisher of, for example, fused silica and single crystal silicon, silicon carbide and other materials. In one example, workpiece material is removed at the atomic level through reaction with fluorine atoms. In this example, these reactive species are produced by a noble gas plasma from trace constituent fluorocarbons or other fluorine containing gases added to the host argon matrix. The products of the reaction are gas phase compounds that flow from the surface of the workpiece, exposing fresh material to the etchant without condensation and redeposition on the newly created surface. The discharge provides a stable and predictable distribution of reactive species permitting the generation of a predetermined surface by translating the plasma across the workpiece along a calculated path.

  1. Evaluation of Bulk and Surface Radiation Damage of Silicon Sensors for the ATLAS Upgrade

    CERN Document Server

    Mikeštíková, Marcela; Št'astný, Jan

    2015-01-01

    The electrical characteristics of different types of end-cap miniature n + -in- p strip sensors, ATLAS12A, were evaluated in Institute of Physics in Prague before and after proton and gamma irradiation. We report here on the bulk damage aspects, including the increase of leakage current and evaluation of the full depletion voltage and the surface damage, including the decrease of inter-strip resistance, changes in inter-strip capacitance and the effectiveness of punch-through protection structure. It was verified that different geometries of end-cap sensors do not influence their stability; the sensors should provide acceptable strip isolation and n ew gate PTP structure functions well even at the highest tested proton fluence 2× 10 15 n eq / cm 2

  2. Simulating damage for wind storms in the land surface model ORCHIDEE-CAN (revision 4262)

    Science.gov (United States)

    Chen, Yi-Ying; Gardiner, Barry; Pasztor, Ferenc; Blennow, Kristina; Ryder, James; Valade, Aude; Naudts, Kim; Otto, Juliane; McGrath, Matthew J.; Planque, Carole; Luyssaert, Sebastiaan

    2018-03-01

    Earth system models (ESMs) are currently the most advanced tools with which to study the interactions among humans, ecosystem productivity, and the climate. The inclusion of storm damage in ESMs has long been hampered by their big-leaf approach, which ignores the canopy structure information that is required for process-based wind-throw modelling. Recently the big-leaf assumptions in the large-scale land surface model ORCHIDEE-CAN were replaced by a three-dimensional description of the canopy structure. This opened the way to the integration of the processes from the small-scale wind damage risk model ForestGALES into ORCHIDEE-CAN. The integration of ForestGALES into ORCHIDEE-CAN required, however, developing numerically efficient solutions to deal with (1) landscape heterogeneity, i.e. account for newly established forest edges for the parameterization of gusts; (2) downscaling spatially and temporally aggregated wind fields to obtain more realistic wind speeds that would represents gusts; and (3) downscaling storm damage within the 2500 km2 pixels of ORCHIDEE-CAN. This new version of ORCHIDEE-CAN was parameterized over Sweden. Subsequently, the performance of the model was tested against data for historical storms in southern Sweden between 1951 and 2010 and south-western France in 2009. In years without big storms, here defined as a storm damaging less than 15 × 106 m3 of wood in Sweden, the model error is 1.62 × 106 m3, which is about 100 % of the observed damage. For years with big storms, such as Gudrun in 2005, the model error increased to 5.05 × 106 m3, which is between 10 and 50 % of the observed damage. When the same model parameters were used over France, the model reproduced a decrease in leaf area index and an increase in albedo, in accordance with SPOT-VGT and MODIS records following the passing of Cyclone Klaus in 2009. The current version of ORCHIDEE-CAN (revision 4262) is therefore expected to have the capability to capture the dynamics of

  3. The study of sub-surface damage distributions during grinding process on different abrasion materials

    Science.gov (United States)

    Kuo, Ching-Hsiang; Huang, Chien-Yao; Yu, Zong-Ru; Shu, Shyu-Cheng; Chang, Keng-Shou; Hsu, Wei-Yao

    2017-10-01

    The grinding process is the primary technology for curvature generation (CG) on glass optics. The higher material removal rate (MRR) leads to deeper sub-surface damage (SSD) on lens surface. The SSD must be removed by following lapping and polishing processes to ensure the lens quality. However, these are not an easy and an efficient process to remove the SSD from ground surface directly for aspheric surfaces with tens or hundreds microns departure from bestfit- sphere (BFS). An efficient fabrication procedure for large aspheric departure on glass materials must be considered. We propose 3-step fabrication procedures for aspheric surface with larger departure. 1st step is to generate a specific aspheric surface with depth less than 10 μm of SSD residual. 2nd step is to remove SSD and keep the aspheric form by using Zeeko polisher with higher MRR pad. Final step is to figure and finish the aspheric surface by using QED MRF machine. In this study, we focus on the 1st step to investigate the residual depth of SSD after grinding process on different abrasion materials. The materials of tested part are fused silica, S-NPH2, and S-PHM52. The cross grinding would be configured and depth of SSD/surface roughness would be evaluated in this study. The characteristic of SSD could be observed after etching by confocal microscope. The experimental results show the depth of SSD below 31.1 μm with #400 grinding wheel. And the near 10 μm depth of SSD would be achieved with #1,000 grinding wheel. It means the aspherization polishing on large parts with large departure from best fit sphere would be replaced. The fabrication of large aspheric part would be efficient.

  4. Dynamic modeling and vibration characteristics analysis of the aero-engine dual-rotor system with Fan blade out

    Science.gov (United States)

    Yu, Pingchao; Zhang, Dayi; Ma, Yanhong; Hong, Jie

    2018-06-01

    Fan Blade Out (FBO) from a running rotor of the turbofan engine will not only introduce the sudden unbalance and inertia asymmetry into the rotor, but also apply large impact load and induce rotor-to-stator rubbing on the rotor, which makes the mass, gyroscopic and stiffness matrixes of the dynamic equation become time-varying and highly nonlinear, consequently leads to the system's complicated vibration. The dynamic analysis of the aero-engine rotor system is one essential requirement of the authorities and is vital to the aero-engine's safety. The paper aims at studying the dynamic responses of the complicated dual-rotor systems at instantaneous and windmilling statuses when FBO event occurs. The physical process and mechanical characteristics of the FBO event are described qualitatively, based on which the dynamic modeling for an aero-engine dual-rotor system is carried out considering several excitations caused by FBO. Meanwhile the transient response during the instantaneous status and steady-state response at the windmilling status are obtained. The results reveal that the sudden unbalance can induce impact load to the rotor, and lead to the sharp increase of the vibration amplitude and reaction force. The rub-impact will apply constraint effects on the rotor and restrict the transient vibration amplitude, while the inertia asymmetry has little influence on the transient response. When the rotor with huge unbalance operates at windmilling status, the rub-impact turns to be the main factor determining the rotor's dynamic behavior, and several potential motion states, such as instable dry whip, intermittent rubbing and synchronous full annular rubbing would happen on certain conditions.

  5. One Generation of New Material, One Generation of New Type Engine:Development Trend of Aero-engine and Its Requirements for Materials

    Directory of Open Access Journals (Sweden)

    LIU Da-xiang

    2017-10-01

    Full Text Available Based on the brief review of accelerated developing status of aircraft power technology in the world, the present status and developing trend of key materials technology for aero-engine were analyzed. In accordance with the idea of "one generation of new material, one generation of new type engine", development requirements for the materials technology of the system and main parts of aero-engine were proposed. Suggestions for improving development and application level of the materials technology in China were presented from aspects of quality stability and technical maturity, investigation and verification for engineering, materials system and data, composite materials, airworthiness certificate,etc.

  6. AFM assessment of the surface nano/microstructure on chemically damaged historical and model glasses

    Energy Technology Data Exchange (ETDEWEB)

    Carmona, Noemi [Centro Nacional de Investigaciones Metalurgicas, CSIC, Avda. Gregorio del Amo, 8, 28040 Madrid (Spain); Kowal, Andrzej [Institute of Catalysis and Surface Chemistry, PAN, ul. Niezapominajek 8, 30239 Cracow (Poland); Rincon, Jesus-Maria [Instituto Eduardo Torroja de Ciencias de la Construccion, CSIC, C. Serrano Galvache s/n, 28033 Madrid (Spain); Villegas, Maria-Angeles, E-mail: mariangeles.villegas@cchs.csic.es [Centro Nacional de Investigaciones Metalurgicas, CSIC, Avda. Gregorio del Amo, 8, 28040 Madrid (Spain); Instituto de Historia, Centro de Ciencias Humanas y Sociales, CSIC, C. Albasanz, 26-28, 28037 Madrid (Spain)

    2010-01-15

    Surface chemical damage on selected historical glasses from 13th to 19th centuries was evaluated by means of atomic force microscopy (AFM). Nano- and microstructure, roughness and topography of ancient glass samples have been compared with those of model glasses prepared by conventional melting at the laboratory with similar compositions to those most frequently found in historical glass pieces. The results obtained allow discussing the chemical degradation mechanisms in terms of the acid and/or basic chemical attack carried out by the combination of gaseous pollutants and environmental humidity. Even though deep corrosion features escape to the observation order of magnitude of the AF microscope used, the AFM technique proves to be quite useful for the study and evaluation of the most common surface pathologies of historical glasses with different compositions once submitted to natural weathering.

  7. AFM assessment of the surface nano/microstructure on chemically damaged historical and model glasses

    International Nuclear Information System (INIS)

    Carmona, Noemi; Kowal, Andrzej; Rincon, Jesus-Maria; Villegas, Maria-Angeles

    2010-01-01

    Surface chemical damage on selected historical glasses from 13th to 19th centuries was evaluated by means of atomic force microscopy (AFM). Nano- and microstructure, roughness and topography of ancient glass samples have been compared with those of model glasses prepared by conventional melting at the laboratory with similar compositions to those most frequently found in historical glass pieces. The results obtained allow discussing the chemical degradation mechanisms in terms of the acid and/or basic chemical attack carried out by the combination of gaseous pollutants and environmental humidity. Even though deep corrosion features escape to the observation order of magnitude of the AF microscope used, the AFM technique proves to be quite useful for the study and evaluation of the most common surface pathologies of historical glasses with different compositions once submitted to natural weathering.

  8. Surface Contaminant Control Technologies to Improve Laser Damage Resistance of Optics

    Directory of Open Access Journals (Sweden)

    Xiaofeng Cheng

    2014-01-01

    Full Text Available The large high-power solid lasers, such as the National Ignition Facility (NIF of America and the Shenguang-III (SG-III laser facility of China, can output over 2.1 MJ laser pulse for the inertial confinement fusion (ICF experiments. Because of the enhancement of operating flux and the expansion of laser driver scale, the problem of contamination seriously influences their construction period and operation life. During irradiation by intense laser beams, the contaminants on the metallic surface of beam tubes can be transmitted to the optical surfaces and lead to damage of optical components. For the high-power solid-state laser facilities, contamination control focuses on the slab amplifiers, spatial filters, and final-optical assemblies. In this paper, an effective solution to control contaminations including the whole process of the laser driver is put forward to provide the safe operation of laser facilities, and the detailed technical methods of contamination control such as washing, cleanliness metrology, and cleanliness protecting are also introduced to reduce the probability of laser-induced damage of optics. The experimental results show that the cleanliness level of SG-III laser facility is much better to ensure that the laser facility can safely operate at high energy flux.

  9. Transient stress control of aeroengine disks based on active thermal management

    International Nuclear Information System (INIS)

    Ding, Shuiting; Wang, Ziyao; Li, Guo; Liu, Chuankai; Yang, Liu

    2016-01-01

    Highlights: • The essence of cooling in turbine system is a process of thermal management. • Active thermal management is proposed to control transient stress of disks. • The correlation between thermal load and transient stress of disks is built. • Stress level can be declined by actively adjusting the thermal load distribution. • Artificial temperature gradient can be used to counteract stress from rotating. - Abstract: The physical essence of cooling in the turbine system is a process of thermal management. In order to overcome the limits of passive thermal management based on thermal protection, the concept of active thermal management based on thermal load redistribution has been proposed. On this basis, this paper focuses on a near real aeroengine disk during a transient process and studies the stress control mechanism of active thermal management in transient conditions by a semi-analytical method. Active thermal management is conducted by imposing extra heating energy on the disk hub, which is represented by the coefficient of extra heat flow η. The results show that the transient stress level can be effectively controlled by actively adjusting the thermal load distribution. The decline ratio of the peak equivalent stress of the disk hub can be 9.0% for active thermal management load condition (η = 0.2) compared with passive condition (η = 0), even at a rotation speed of 10,000 r/min. The reason may be that the temperature distribution of the disk turns into an artificial V-shape because of the extra heating energy on the hub, and the resulting thermal stresses induced by the negative temperature gradients counteract parts of the stress from rotating.

  10. Surface damage in TEM thick α-Fe samples by implantation with 150 keV Fe ions

    International Nuclear Information System (INIS)

    Aliaga, M.J.; Caturla, M.J.; Schäublin, R.

    2015-01-01

    We have performed molecular dynamics simulations of implantation of 150 keV Fe ions in pure bcc Fe. The thickness of the simulation box is of the same order of those used in in situ TEM analysis of irradiated materials. We assess the effect of the implantation angle and the presence of front and back surfaces. The number and type of defects, ion range, cluster distribution and primary damage morphology are studied. Results indicate that, for the very thin samples used in in situ TEM irradiation experiments the presence of surfaces affect dramatically the damage produced. At this particular energy, the ion has sufficient energy to damage both the top and the back surfaces and still leave the sample through the bottom. This provides new insights on the study of radiation damage using TEM in situ

  11. Formation of plasma induced surface damage in silica glass etching for optical waveguides

    International Nuclear Information System (INIS)

    Choi, D.Y.; Lee, J.H.; Kim, D.S.; Jung, S.T.

    2004-01-01

    Ge, B, P-doped silica glass films are widely used as optical waveguides because of their low losses and inherent compatibility with silica optical fibers. These films were etched by ICP (inductively coupled plasma) with chrome etch masks, which were patterned by reactive ion etching (RIE) using chlorine-based gases. In some cases, the etched surfaces of silica glass were very rough (root-mean square roughness greater than 100 nm) and we call this phenomenon plasma induced surface damage (PISD). Rough surface cannot be used as a platform for hybrid integration because of difficulty in alignment and bonding of active devices. PISD reduces the etch rate of glass and it is very difficult to remove residues on a rough surface. The objective of this study is to elucidate the mechanism of PISD formation. To achieve this goal, PISD formation during different etching conditions of chrome etch mask and silica glass was investigated. In most cases, PISD sources are formed on a glass surface after chrome etching, and metal compounds are identified in theses sources. Water rinse after chrome etching reduces the PISD, due to the water solubility of metal chlorides. PISD is decreased or even disappeared at high power and/or low pressure in glass etching, even if PISD sources were present on the glass surface before etching. In conclusion, PISD sources come from the chrome etching process, and polymer deposition on these sources during the silica etching cause the PISD sources to grow. In the area close to the PISD source there is a higher ion flux, which causes an increase in the etch rate, and results in the formation of a pit

  12. Characterization of thermomechanical damage on tungsten surfaces during long-duration plasma transients

    Energy Technology Data Exchange (ETDEWEB)

    Rivera, David, E-mail: david.rivera.ucla@gmail.com; Crosby, Tamer; Sheng, Andrew; Ghoniem, Nasr M.

    2014-12-15

    A new experimental facility constructed at UCLA for the simulation of high heat flux effects on plasma-facing materials is described. The High Energy Flux Test Facility (HEFTY) is equipped with a Praxair model SG-100 plasma gun, which is nominally rated at 80 kW of continuous operation, of which approximately 30 kW reaches the target due to thermal losses. The gun is used to impart high intermittent heat flux to metal samples mounted within a cylindrical chamber. The system is capable of delivering an instantaneous heat flux in the range of 30–300 MW/m{sup 2}, depending on sample proximity to the gun. The duration of the plasma heat flux is in the range of 1–1000 s, making it ideal for studies of mild plasma transients of relatively long duration. Tungsten and tungsten-copper alloy metal samples are tested in these transient heat flux conditions, and the surface is characterized for damage evaluation using optical, SEM, XRD, and micro-fabrication techniques. Results from a Finite Element (FE) thermo-elastoplasticity model indicate that during the heat-up phase of a plasma transient pulse, the majority of the sample surface is under compressive stresses leading to plastic deformation of the surface. Upon sample cooling, the recovered elastic strain of cooler parts of the sample exceeds that from parts that deformed plastically, resulting in a tensile surface self-stress (residual surface stress). The intensity of the residual tensile surface stress is experimentally correlated with the onset of complex surface fracture morphology on the tungsten surface, and extending below the surface region. Micro-compression mechanical tests of W micro-pillars show that the material has significant plasticity, failing by a “barreling” mode before plasma exposure, and by normal dislocation slip and localized shear after plasma exposure. Ongoing modeling of the complex thermo-fracture process, coupled with elasto-plasticity is based on a phase field approach for distributed

  13. Quantification of acute vocal fold epithelial surface damage with increasing time and magnitude doses of vibration exposure.

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Kojima

    Full Text Available Because the vocal folds undergo repeated trauma during continuous cycles of vibration, the epithelium is routinely susceptible to damage during phonation. Excessive and prolonged vibration exposure is considered a significant predisposing factor in the development of vocal fold pathology. The purpose of the present study was to quantify the extent of epithelial surface damage following increased time and magnitude doses of vibration exposure using an in vivo rabbit phonation model. Forty-five New Zealand white breeder rabbits were randomized to nine groups and received varying phonation time-doses (30, 60, or 120 minutes and magnitude-doses (control, modal intensity phonation, or raised intensity phonation of vibration exposure. Scanning electron microscopy and transmission electron microscopy was used to quantify the degree of epithelial surface damage. Results revealed a significant reduction in microprojection density, microprojection height, and depth of the epithelial surface with increasing time and phonation magnitudes doses, signifying increased epithelial surface damage risk with excessive and prolonged vibration exposure. Destruction to the epithelial cell surface may provide significant insight into the disruption of cell function following prolonged vibration exposure. One important goal achieved in the present study was the quantification of epithelial surface damage using objective imaging criteria. These data provide an important foundation for future studies of long-term tissue recovery from excessive and prolonged vibration exposure.

  14. Detection of a milling-induced surface damage by the magnetic Barkhausen noise

    Science.gov (United States)

    Stupakov, A.; Neslušan, M.; Perevertov, O.

    2016-07-01

    The potential of the magnetic Barkhausen noise method for a non-destructive evaluation of the steel surface damage cased by milling was comprehensively investigated. A typical bearing steel was heat treated to three different hardnesses and then machined using the cutting tools with different degrees of the flank wear. The magnetic low-frequency measurements with a high reading depth were performed using a unique laboratory system providing a full control of the magnetization process. The high-frequency measurements were performed using a commercial Rollscan device. To study the induced magnetic anisotropy, the measurements were performed in two magnetization directions. In the feeding direction, the Barkhausen noise profiles showed a second high-field peak ascribed to an induced hardened surface layer, a so-called white layer. The most reliable results were obtained with the controlled waveform of the surface magnetic field measured directly by Hall sensors. In the perpendicular rotation direction, formation of the preferentially oriented matrix resulted in an enormously high Barkhausen noise activity. Based on these results, new magnetic parameters were proposed for the non-destructive evaluation of the white layer formation.

  15. Damage at a tungsten surface induced by impacts of self-atoms

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yong [Data Center for High Energy Density Physics, Institute of Applied Physics and, Computational Mathematics, P. O. Box 8009, Beijing 100088 (China); Krstic, Predrag, E-mail: predrag.krstic@stonybrook.edu [Institute for Advanced Computational Science, Stony Brook University, Stony Brook, NY 11794-5250 (United States); Zhou, Fu Yang [College of Material Sciences and Optoelectronic Technology, University of the Chinese Academy of Sciences, P. O. Box 4588, Beijing 100049 (China); Meyer, Fred [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6372 (United States)

    2015-12-15

    We study evolution of the surface defects of a 300 K tungsten surface due to the cumulative impact of 0.25–10 keV self-atoms. The simulation is performed by molecular dynamics with bond-order Tersoff-form potentials. At all studied impact energies the computation shows strong defect-recombination effect of both created Frenkel pairs as well as recombination of the implanted atoms with the vacancies created by the sputtering. This leads to a saturation of the cumulative count of vacancies, evident at energies below 2 keV, as long as the implantation per impact atom exceeds sputtering and to a saturation of the interstitial count when production of the sputtered particles per impact atom becomes larger than 1 (in the energy range 2-4 keV). The number of cumulative defects is fitted as functions of impact fluence and energy, enabling their analytical extrapolation outside the studied range of parameters. - Highlights: • We calculated cumulative creation of defects in tungsten by self-atom impact. • At some energies, the defect count saturate with increasing damage dose. • The defects are accumulated in the first few layers of the tungsten surface. • The interstitials are formed predominantly as adatoms.

  16. Surface damage on 6H–SiC by highly-charged Xeq+ ions irradiation

    International Nuclear Information System (INIS)

    Zhang, L.Q.; Zhang, C.H.; Han, L.H.; Xu, C.L.; Li, J.J.; Yang, Y.T.; Song, Y.; Gou, J.; Li, J.Y.; Ma, Y.Z.

    2014-01-01

    Surface damage on 6H–SiC irradiated by highly-charged Xe q+ (q = 18, 26) ions to different fluences in two geometries was studied by means of AFM, Raman scattering spectroscopy and FTIR spectrometry. The FTIR spectra analysis shows that for Xe 26+ ions irradiation at normal incidence, a deep reflection dip appears at about 930 cm −1 . Moreover, the reflectance on top of reststrahlen band decreases as the ion fluence increases, and the reflectance at tilted incidence is larger than that at normal incidence. The Raman scattering spectra reveal that for Xe 26+ ions at normal incidence, surface reconstruction occurs and amorphous stoichiometric SiC and Si–Si and C–C bonds are generated and original Si–C vibrational mode disappears. And the intensity of scattering peaks decreases with increasing dose. The AFM measurement shows that the surface swells after irradiation. With increasing ion fluence, the step height between the irradiated and the unirradiated region increases for Xe 18+ ions irradiation; while for Xe 26+ ions irradiation, the step height first increases and then decreases with increasing ion fluence. Moreover, the step height at normal incidence is higher than that at tilted incidence by the irradiation with Xe 18+ to the same ion fluence. A good agreement between the results from the three methods is found

  17. Geometry and surface damage in micro electrical discharge machining of micro-holes

    Science.gov (United States)

    Ekmekci, Bülent; Sayar, Atakan; Tecelli Öpöz, Tahsin; Erden, Abdulkadir

    2009-10-01

    Geometry and subsurface damage of blind micro-holes produced by micro electrical discharge machining (micro-EDM) is investigated experimentally to explore the relational dependence with respect to pulse energy. For this purpose, micro-holes are machined with various pulse energies on plastic mold steel samples using a tungsten carbide tool electrode and a hydrocarbon-based dielectric liquid. Variations in the micro-hole geometry, micro-hole depth and over-cut in micro-hole diameter are measured. Then, unconventional etching agents are applied on the cross sections to examine micro structural alterations within the substrate. It is observed that the heat-damaged segment is composed of three distinctive layers, which have relatively high thicknesses and vary noticeably with respect to the drilling depth. Crack formation is identified on some sections of the micro-holes even by utilizing low pulse energies during machining. It is concluded that the cracking mechanism is different from cracks encountered on the surfaces when machining is performed by using the conventional EDM process. Moreover, an electrically conductive bridge between work material and debris particles is possible at the end tip during machining which leads to electric discharges between the piled segments of debris particles and the tool electrode during discharging.

  18. Geometry and surface damage in micro electrical discharge machining of micro-holes

    International Nuclear Information System (INIS)

    Ekmekci, Bülent; Sayar, Atakan; Öpöz, Tahsin Tecelli; Erden, Abdulkadir

    2009-01-01

    Geometry and subsurface damage of blind micro-holes produced by micro electrical discharge machining (micro-EDM) is investigated experimentally to explore the relational dependence with respect to pulse energy. For this purpose, micro-holes are machined with various pulse energies on plastic mold steel samples using a tungsten carbide tool electrode and a hydrocarbon-based dielectric liquid. Variations in the micro-hole geometry, micro-hole depth and over-cut in micro-hole diameter are measured. Then, unconventional etching agents are applied on the cross sections to examine micro structural alterations within the substrate. It is observed that the heat-damaged segment is composed of three distinctive layers, which have relatively high thicknesses and vary noticeably with respect to the drilling depth. Crack formation is identified on some sections of the micro-holes even by utilizing low pulse energies during machining. It is concluded that the cracking mechanism is different from cracks encountered on the surfaces when machining is performed by using the conventional EDM process. Moreover, an electrically conductive bridge between work material and debris particles is possible at the end tip during machining which leads to electric discharges between the piled segments of debris particles and the tool electrode during discharging

  19. Enamel cracks evaluation - A method to predict tooth surface damage during the debonding.

    Science.gov (United States)

    Dumbryte, Irma; Jonavicius, Tomas; Linkeviciene, Laura; Linkevicius, Tomas; Peciuliene, Vytaute; Malinauskas, Mangirdas

    2015-01-01

    The objective of this in vitro study was to evaluate the effect of the enamel cracks on the tooth damage during the debonding. Measurements of the cracks characteristics (visibility, direction, length, and location) were performed utilizing a scanning electron microscopy (SEM) technique and mathematically derived formulas (x=h/30, l=n*x) before and following the removal of mechanically retained metal and ceramic brackets. The likelihood of having greater extent enamel defects was higher for the teeth with pronounced cracks (odds vatios, OR=3.728), increased when the crack was located in more than one zone of the tooth (OR=1.998), and the inclination did not exceed 30-45° (OR=0.505). Using ceramic brackets the risk of greater amount tooth structure defects raised 1.45 times (OR=1.450). Enamel crack showing all these characteristics at the beginning of the orthodontic treatment and the use of ceramic brackets might predispose to higher risk of greater extent tooth surface damage after the debonding by 20.4%.

  20. Silicon surface damage caused by reactive ion etching in fluorocarbon gas mixtures containing hydrogen

    International Nuclear Information System (INIS)

    Norstroem, H.; Blom, H.; Ostling, M.; Nylandsted Larsen, A.; Keinonen, J.; Berg, S.

    1991-01-01

    For selective etching of SiO 2 on silicon, gases or gas mixtures containing hydrogen are often used. Hydrogen from the glow discharge promotes the formation of a thin film polymer layer responsible for the selectivity of the etching process. The reactive ion etch (RIE) process is known to create damage in the silicon substrate. The influence of hydrogen on the damage and deactivation of dopants is investigated in the present work. The distribution of hydrogen in silicon, after different etching and annealing conditions have been studied. The influence of the RIE process on the charge carrier concentration in silicon has been investigated. Various analytical techniques like contact resistivity measurements, four point probe measurements, and Hall measurements have been used to determine the influence of the RIE process on the electrical properties of processed silicon wafers. The hydrogen profile in as-etched and post annealed wafers was determined by the 1 H( 15 N,αγ) 12 C nuclear reaction. The depth of the deactivated surface layer is discussed in terms of the impinging hydrogen ion energy, i.e., the possibility of H + ions to pick up an energy equal to the peak-to-peak voltage of the rf signal

  1. Study of clean and ion bombardment damaged silver single crystal surfaces by work function measurements

    International Nuclear Information System (INIS)

    Chelvayohan, N.

    1982-06-01

    Work function values of the (110), (100) and (111) faces of silver single crystal were measured by the photoelectric emission method and found to be 4.14 +- 0.04 eV, 4.22 +-0.04 eV and 4.46 +- 0.02 eV respectively. Oxygen adsorption on the faces were studied by surface potential measurement. Strong oxygen adsorption was observed on (110) and (100) faces, whereas the (111) face was found to be inert for oxygen adsorption. Oxygen adsorption on the (111) face damaged by argon ion bombardment was also investigated. The above results were compared with those of early reported work function and oxygen adsorption values. (U.K.)

  2. APPLICATION OF ROUGH SET THEORY TO MAINTENANCE LEVEL DECISION-MAKING FOR AERO-ENGINE MODULES BASED ON INCREMENTAL KNOWLEDGE LEARNING

    Institute of Scientific and Technical Information of China (English)

    陆晓华; 左洪福; 蔡景

    2013-01-01

    The maintenance of an aero-engine usually includes three levels ,and the maintenance cost and period greatly differ depending on the different maintenance levels .To plan a reasonable maintenance budget program , airlines would like to predict the maintenance level of aero-engine before repairing in terms of performance parame-ters ,which can provide more economic benefits .The maintenance level decision rules are mined using the histori-cal maintenance data of a civil aero-engine based on the rough set theory ,and a variety of possible models of upda-ting rules produced by newly increased maintenance cases added to the historical maintenance case database are in-vestigated by the means of incremental machine learning .The continuously updated rules can provide reasonable guidance suggestions for engineers and decision support for planning a maintenance budget program before repai-ring .The results of an example show that the decision rules become more typical and robust ,and they are more accurate to predict the maintenance level of an aero-engine module as the maintenance data increase ,which illus-trates the feasibility of the represented method .

  3. Automated analysis of damages for radiation in plastics surfaces; Analisis automatizado de danos por radiacion en superficies plasticas

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, C; Camacho M, E; Tavera, L; Balcazar, M [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1990-02-15

    Analysis of damages done by the radiation in a polymer characterized by optic properties of polished surfaces, of uniformity and chemical resistance that the acrylic; resistant until the 150 centigrade grades of temperature, and with an approximate weight of half of the glass. An objective of this work is the development of a method that analyze in automated form the superficial damages induced by radiation in plastic materials means an images analyst. (Author)

  4. Roller Testing to Mimic Damage of the ISS SARJ Ring and Durability Test to Simulate Fifteen Years of SARJ Operation Using the Damaged Surface

    Science.gov (United States)

    Krantz, Timothy L.; Elchert, Justin P.; DellaCorte, Christopher; Dube, Michael J.

    2016-01-01

    The International Space Station's starboard Solar Alpha Rotary Joint (SARJ) experienced a breakdown of the joint's race ring surface. The starboard SARJ mechanism was cleaned and lubricated with grease. To provide some guidance on the expected behavior of the damaged SARJ ring with continued operations, experiments were conducted using rollers and a vacuum roller test rig. The approach of the experimental work involved three main steps: (1) initiate damage using conditions representative of the SARJ with inadequate lubrication; (2) propagate the damage by operating the test rollers without lubrication; and (3) assess the durability of the roller by testing to simulate the equivalent of 15 years of SARJ operation on the damaged surface assuming adequate grease lubrication. During the rig testing, additional and/or replacement grease was introduced at regular intervals to maintain good lubrication in the rig. The damage to the nitride layer continued even after application of grease. The grease lubrication proved to be effective for limiting the value of the axial force that can be developed. Limiting the axial force on the SARJ mechanism is important since the larger the axial force the more concentrated the load pressure becomes on the blend-radius location on the SARJ roller. After the testing simulating 15 years of SARJ operations, the wear depths were the order of 0.2 mm for the nitrided 15-5 roller and the order of 0.06 mm for the mating 440C roller. Metallographic inspections were done to search for indications of impending fatigue or other fracture indications that might eventually propagate and cause structural failure. There were no indications or features found that could eventually compromise structural integrity.

  5. Standard test method for damage to contacting solid surfaces under fretting conditions

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the studying or ranking the susceptibility of candidate materials to fretting corrosion or fretting wear for the purposes of material selection for applications where fretting corrosion or fretting wear can limit serviceability. 1.2 This test method uses a tribological bench test apparatus with a mechanism or device that will produce the necessary relative motion between a contacting hemispherical rider and a flat counterface. The rider is pressed against the flat counterface with a loading mass. The test method is intended for use in room temperature air, but future editions could include fretting in the presence of lubricants or other environments. 1.3 The purpose of this test method is to rub two solid surfaces together under controlled fretting conditions and to quantify the damage to both surfaces in units of volume loss for the test method. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5...

  6. Gear Fault Detection Effectiveness as Applied to Tooth Surface Pitting Fatigue Damage

    Science.gov (United States)

    Lewicki, David G.; Dempsey, Paula J.; Heath, Gregory F.; Shanthakumaran, Perumal

    2010-01-01

    A study was performed to evaluate fault detection effectiveness as applied to gear-tooth-pitting-fatigue damage. Vibration and oil-debris monitoring (ODM) data were gathered from 24 sets of spur pinion and face gears run during a previous endurance evaluation study. Three common condition indicators (RMS, FM4, and NA4 [Ed. 's note: See Appendix A-Definitions D were deduced from the time-averaged vibration data and used with the ODM to evaluate their performance for gear fault detection. The NA4 parameter showed to be a very good condition indicator for the detection of gear tooth surface pitting failures. The FM4 and RMS parameters perfomu:d average to below average in detection of gear tooth surface pitting failures. The ODM sensor was successful in detecting a significant 8lDOunt of debris from all the gear tooth pitting fatigue failures. Excluding outliers, the average cumulative mass at the end of a test was 40 mg.

  7. Surface damage and gas trapping profile measurements in copper during 20 kev He+ irradiation

    International Nuclear Information System (INIS)

    Terreault, B.; Veilleux, G.

    1980-01-01

    Surface damage due to 20 keV he + irradiation of OFHC Cu was studied by optical and scanning electron microscopy, and by gas trapping profile measurements with proton backscattering and elastic recoil detection. Both annealed (1 h at 773 K) and unannealed Cu were implanted, at 300 K (0.22Tsub(m)) and 500 K(0.37 Tsub(m)), up to fluences of 3 x 10 18 cm -2 . Additional results with thin (1 μm) evaporated films and stressed cold-rolled foils (3 μm) were obtained. At 500 K in bulk OFHC Cu pores and/or large (approx. 1μm) but scattered blisters appear; at 300 K in bulk or thin film Cu blisters are large and abundant. In all these cases a very large (>=1.5 x 10 1 7 cm -2 ) and sudden release of deeply implanted helium takes place, leading to a depleted profile at a depth of about 90 nm (approx. Rsub(p)). In contrast in cold-rolled foils the blisters are small (approx. 0.4 μm) and the profiles are undepleted. These results are explained by fissuration of helium-pressurized cavities. At high fluence blisters disappear, leaving a porous structure at 500 K and a rough micro-relief at 300 K; the helim profiles are flat and very wide (2-3 Rsub(p)). Blister disappearance, absence of flaking, and porous structure are discussed in terms of the width of the profiles and the formation of a helium-saturated, highly damaged (recrystallized), and permeable layer. (orig.)

  8. The size prediction of potential inclusions embedded in the sub-surface of fused silica by damage morphology

    Directory of Open Access Journals (Sweden)

    Gao Xiang

    2017-04-01

    Full Text Available A model for predicting the size ranges of different potential inclusions initiating damage on the surface of fused silica has been presented. This accounts for the heating of nanometric inclusions whose absorptivity is described based on Mie Theory. The depth profile of impurities has been measured by ICP-OES. By the measured temporal pulse profile on the surface of fused silica, the temperature and thermal stress has been calculated. Furthermore, considering the limit conditions of temperature and thermal stress strength for different damage morphologies, the size range of potential inclusions for fused silica is discussed.

  9. The Study of Foreign Object Damage Caused by Aircraft Operations on Unconventional and Bomb-Damaged Airfield Surfaces.

    Science.gov (United States)

    1981-06-01

    missile IR seeker heads and EO missiles such as MAVERICK should not be a problem for limited exposure of takeoff and landing. (3) Aircraft engines are...no rocks are thrown ahead of the tire. b. A trampoline effect exists directly behind the tire wherein the rebound of the soil tosses the surface...the fuselage skin as 138 scratches in the paint. One possible explanation is that the stones were raised by the trampoline effect and then received an

  10. Effect of Cavitation on Surface Damage of 16.7Cr-10Ni-2Mo Stainless Steel in Marine Environment

    Energy Technology Data Exchange (ETDEWEB)

    Chong, Sang-Ok; Han, Min-Su; Kim, Seong-Jong [Mokpo National Maritime University, Mokpo (Korea, Republic of)

    2015-10-15

    Stainless steel is generally known to have characteristics of excellent corrosion resistance and durability, but in a marine environment it can suffer from localized corrosion due to the breakdown of passivity film due to chloride ion in seawater. Furthermore, the damage behaviors are sped up under a cavitation environment because of complex damage from electrochemical corrosion and cavitation-erosion. In this study the characteristics of electrochemical corrosion and cavitation erosion behavior were evaluated on 16.7Cr-10Ni-2Mo stainless steel under a cavitation environment in natural seawater. The electrochemical experiments have been conducted at both static conditions and dynamic conditions inducing cavitation with different current density parameters. The surface morphology and damage behaviors were compared after the experiment. After the cavitation test with time variables morphological examinations on damaged specimens were analyzed by using a scanning electron microscope and a 3D microscope. the galvanostatic experiment gave a cleaner surface morphology presented with less damage depth at high current density regions. It is due to the effect of water cavitation peening under the cavitation condition. In the cavitation experiment, with amplitude of 30 μm and seawater temperature of 25 ℃, weight loss and cavitation-erosion damage depth were dramatically increased after 5 hours inducing cavitation.

  11. Biconvex intraocular lenses and Nd:YAG capsulotomy: Experimental comparison of surface damage with different poly(methyl methacrylate) formulations

    Energy Technology Data Exchange (ETDEWEB)

    Downing, J.E.; Alberhasky, M.T. (Greenview Hospital, Bowling Green, KY (USA))

    1990-11-01

    Biconvex posterior chamber lenses have optical advantages and decrease the risk of capsular opacification, but they are more likely to be pitted during ND:YAG capsulotomy because of apposition of the lens to the capsule. This study reports the likelihood of surface damage to different formulations of poly(methyl methacrylate) at the energy levels required to open posterior capsules. Molded lenses are more easily damaged than higher molecular weight lathe-cut materials (P less than .01), as expected. However, by keeping energy output low, even injection-molded lenses showed minimal damage, with mean pit size 39 +/- 39 microns at 1 mJ. By using a converging contact lens, low power, and keeping the focus behind the capsule, damage to all materials tested should be clinically insignificant.

  12. Scratch resistance and localised damage characteristics of polymer surfaces - a review

    Energy Technology Data Exchange (ETDEWEB)

    Briscoe, B.J. [Department of Chemical Engineering and Chemical Technology, Imperial College, London SW7 2BY (United Kingdom); Sinha, S.K. [Department of Mechanical Engineering, National University of Singapore (Singapore)

    2003-11-01

    The ''Scratch Test'' is, arguably, the earliest and amongst the now most widely used techniques for evaluating a wide range of surface mechanical properties. Some of the areas where this test has been successfully used in the engineering field, both by research and industry, include the determination of the relative hardness of materials, characterizations of coatings, paints and thin-films, modeling of the wear of materials and the estimation of different material deformation characteristics when subjected to hard asperity damage. In this paper we have reviewed the ''state-of-the-art'' in the scratch method for polymeric materials. The paper provides some important theoretical models that have been developed in the field of scratching for material property characterizations. Results from different types of scratch tests (macro, micro and nano scales) on a range of polymeric materials are presented with critical discussion on the usefulness of each result. Finally, various areas for further research in scratching of polymer surfaces have been identified. (Abstract Copyright [2003], Wiley Periodicals, Inc.) [German] Der ''Ritztest'' ist wohl das aelteste und mit am meisten verwendete Verfahren zur Beurteilung von oberflaechenmechanischen Eigenschaften. Zu den technischen Bereichen, in denen dieser Test sowohl in der Forschung als auch in der Industrie erfolgreich Anwendung gefunden hat, zaehlen die Bestimmung der relativen Materialhaerte, die Charakterisierung von Beschichtungen, Lackierungen und Duennschichten, die Modellierung des Werkstoffverschleisses sowie die Abschaetzung verschiedener Werkstoffverformungsparameter bei Beanspruchung durch harte Rauheitsspitzen. Der vorliegende Bericht beschreibt den gegenwaertigen Stand der Anwendung des Ritzverfahrens fuer polymere Materialien. Er enthaelt wichtige theoretische Modelle, die fuer die Anwendung des Ritzens zur Charakterisierung von

  13. Combined Bulk and Surface Radiation Damage Effects at Very High Fluences in Silicon Detectors: Measurements and TCAD Simulations

    CERN Document Server

    Moscatelli, F; Morozzi, A; Mendicino, R; Dalla Betta, G F; Bilei, G M

    2016-01-01

    In this work we propose a new combined TCAD radiation damage modelling scheme, featuring both bulk and surface radiation damage effects, for the analysis of silicon detectors aimed at the High Luminosity LHC. In particular, a surface damage model has been developed by introducing the relevant parameters (NOX, NIT) extracted from experimental measurements carried out on p-type substrate test structures after gamma irradiations at doses in the range 10-500 Mrad(Si). An extended bulk model, by considering impact ionization and deep-level cross-sections variation, was included as well. The model has been validated through the comparison of the simulation findings with experimental measurements carried out at very high fluences (2×1016 1 MeV equivalent n/cm2) thus fostering the application of this TCAD approach for the design and optimization of the new generation of silicon detectors to be used in future HEP experiments.

  14. [Challenge and treatment strategy for ocular surface damage in patients with long term use of antiglaucoma drugs].

    Science.gov (United States)

    He, Xiang-Ge

    2011-02-01

    Long term use of topical anti-glaucoma drugs has been shown to induce chronic conjunctivitis, superficial punctate keratitis (SPK) and dry eye symptom. Under these conditions, a loss of goblet cells in conjunctiva, epithelial squamous metaplasia and apoptosis were morphologically revealed. Benzalkonium Chloride (BKC), a most frequently used preservative in eye drops, has been found to be an important factor causing ocular surface damage. Furthermore, a big challenge for ophthalmologists is that toxic damage of medication to ocular surface tissues is mild, poor specificity, and delayed manifestation in patients, especially when coexisting with other ocular surface diseases. Impairment of ocular surface tissues greatly impacts the life quality of patients and subsequently influences compliance with glaucoma therapy. This paper emphasizes to take measures to prevent ocular surface tissue damage resulted from chronic use of topical anti-glaucoma drugs and further discusses the treatment strategy. Effective and long-lasting action drugs should always be selected for glaucomatous patients in order to decrease the frequency of topical instillation or at a more expensive medication, a fixed combination formula can be considered for glaucoma therapy. An early surgery or laser treatment is also proposed for the patients who require an IOP reduction with an existing ocular surface impairment. Future investigation and development of new medications with long-term efficacy and appropriate BKC are suggested and preservative-free or drugs with new preservative materials recommended.

  15. Volcanic ash ingestion by a large gas turbine aeroengine: fan-particle interaction

    Science.gov (United States)

    Vogel, Andreas; Clarkson, Rory; Durant, Adam; Cassiani, Massimo; Stohl, Andreas

    2016-04-01

    code (CD Adapco STAR-CCM+ with an implicit coupled flow and energy algorithm) for compressible high-speed flows including a Lagrangian particle-tracking model for the simulation of the particle behaviour for typical atmospheric particle size ranges between 1 and 100 μm. The simulations indicate that the predominant proportion of larger particles (> 20 microns) tend to be transported into the bypass duct of the engine (by the centrifugal effect of the fan), whereas the smaller particles follow the fluid flow streamlines and are distributed homogenously in the engine (bypass ducts and core region). This result is significant as it indicates that the absolute ash mass that causes issues for aeroengine operation is a fraction of the ambient (observed or forecast) ash quantity.

  16. He-ion and self-atom induced damage and surface-morphology changes of a hot W target

    International Nuclear Information System (INIS)

    Meyer, F W; Hijazi, H; Bannister, M E; Dadras, J; Krstic, P S; Meyer, H M III; Parish, C M

    2014-01-01

    We report results of measurements on the evolution of the surface morphology of a hot tungsten surface due to impacting low-energy (80–12 000 eV) He ions and of simulations of damage caused by cumulative bombardment of 1 and 10 keV W self-atoms. The measurements were performed at the ORNL Multicharged Ion Research Facility, while the simulations were done at the Kraken supercomputing facility of the University of Tennessee. At 1 keV, the simulations show strong defect-recombination effects that lead to a saturation of the total defect number after a few hundred impacts, while sputtering leads to an imbalance of the vacancy and interstitial number. On the experimental side, surface morphology changes were investigated over a broad range of fluences, energies and temperatures for both virgin and pre-damaged W-targets. At the lowest accumulated fluences, small surface-grain features and near-surface He bubbles are observed. At the largest fluences, individual grain characteristics disappear in focused ion beam/scanning electron microscopy (FIB/SEM) scans, and the entire surface is covered by a multitude of near-surface bubbles with a broad range of sizes, and disordered whisker growth, while in top-down SEM imaging the surface is virtually indistinguishable from the nano-fuzz produced on linear plasma devices. These features are evident at progressively lower fluences as the He-ion energy is increased. (paper)

  17. A new surface fractal dimension for displacement mode shape-based damage identification of plate-type structures

    Science.gov (United States)

    Shi, Binkai; Qiao, Pizhong

    2018-03-01

    Vibration-based nondestructive testing is an area of growing interest and worthy of exploring new and innovative approaches. The displacement mode shape is often chosen to identify damage due to its local detailed characteristic and less sensitivity to surrounding noise. Requirement for baseline mode shape in most vibration-based damage identification limits application of such a strategy. In this study, a new surface fractal dimension called edge perimeter dimension (EPD) is formulated, from which an EPD-based window dimension locus (EPD-WDL) algorithm for irregularity or damage identification of plate-type structures is established. An analytical notch-type damage model of simply-supported plates is proposed to evaluate notch effect on plate vibration performance; while a sub-domain of notch cases with less effect is selected to investigate robustness of the proposed damage identification algorithm. Then, fundamental aspects of EPD-WDL algorithm in term of notch localization, notch quantification, and noise immunity are assessed. A mathematical solution called isomorphism is implemented to remove false peaks caused by inflexions of mode shapes when applying the EPD-WDL algorithm to higher mode shapes. The effectiveness and practicability of the EPD-WDL algorithm are demonstrated by an experimental procedure on damage identification of an artificially-induced notched aluminum cantilever plate using a measurement system of piezoelectric lead-zirconate (PZT) actuator and scanning laser Doppler vibrometer (SLDV). As demonstrated in both the analytical and experimental evaluations, the new surface fractal dimension technique developed is capable of effectively identifying damage in plate-type structures.

  18. Surface-based reconstruction and diffusion MRI in the assessment of gray and white matter damage in multiple sclerosis

    Science.gov (United States)

    Caffini, Matteo; Bergsland, Niels; LaganÃ, Marcella; Tavazzi, Eleonora; Tortorella, Paola; Rovaris, Marco; Baselli, Giuseppe

    2014-03-01

    Despite advances in the application of nonconventional MRI techniques in furthering the understanding of multiple sclerosis pathogenic mechanisms, there are still many unanswered questions, such as the relationship between gray and white matter damage. We applied a combination of advanced surface-based reconstruction and diffusion tensor imaging techniques to address this issue. We found significant relationships between white matter tract integrity indices and corresponding cortical structures. Our results suggest a direct link between damage in white and gray matter and contribute to the notion of gray matter loss relating to clinical disability.

  19. Comparison of laser-based mitigation of fused silica surface damage using mid- versus far-infrared lasers

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S T; Matthews, M J; Elhadj, S; Cooke, D; Guss, G M; Draggoo, V G; Wegner, P J

    2009-12-16

    Laser induced growth of optical damage can limit component lifetime and therefore operating costs of large-aperture fusion-class laser systems. While far-infrared (IR) lasers have been used previously to treat laser damage on fused silica optics and render it benign, little is known about the effectiveness of less-absorbing mid-IR lasers for this purpose. In this study, they quantitatively compare the effectiveness and efficiency of mid-IR (4.6 {micro}m) versus far-IR (10.6 {micro}m) lasers in mitigating damage growth on fused silica surfaces. The non-linear volumetric heating due to mid-IR laser absorption is analyzed by solving the heat equation numerically, taking into account the temperature-dependent absorption coefficient {alpha}(T) at {lambda} = 4.6 {micro}m, while far-IR laser heating is well-described by a linear analytic approximation to the laser-driven temperature rise. In both cases, the predicted results agree well with surface temperature measurements based on infrared radiometry, as well as sub-surface fictive temperature measurements based on confocal Raman microscopy. Damage mitigation efficiency is assessed using a figure of merit (FOM) relating the crack healing depth to laser power required, under minimally-ablative conditions. Based on their FOM, they show that for cracks up to at least 500 {micro}m in depth, mitigation with a 4.6 {micro}m mid-IR laser is more efficient than mitigation with a 10.6 {micro}m far-IR laser. This conclusion is corroborated by direct application of each laser system to the mitigation of pulsed laser-induced damage possessing fractures up to 225 {micro}m in depth.

  20. Laser welding, cutting and surface treatment

    International Nuclear Information System (INIS)

    Crafer, R.C.

    1984-01-01

    Fourteen articles cover a wide range of laser applications in welding, cutting and surface treatment. Future trends are covered as well as specific applications in shipbuilding, the manufacture of heart pacemakers, in the electronics industry, in automobile production and in the aeroengine industry. Safety with industrial lasers and the measurement of laser beam parameters are also included. One article on 'Lasers in the Nuclear Industry' is indexed separately. (U.K.)

  1. Improved laser damage threshold performance of calcium fluoride optical surfaces via Accelerated Neutral Atom Beam (ANAB) processing

    Science.gov (United States)

    Kirkpatrick, S.; Walsh, M.; Svrluga, R.; Thomas, M.

    2015-11-01

    Optics are not keeping up with the pace of laser advancements. The laser industry is rapidly increasing its power capabilities and reducing wavelengths which have exposed the optics as a weak link in lifetime failures for these advanced systems. Nanometer sized surface defects (scratches, pits, bumps and residual particles) on the surface of optics are a significant limiting factor to high end performance. Angstrom level smoothing of materials such as calcium fluoride, spinel, magnesium fluoride, zinc sulfide, LBO and others presents a unique challenge for traditional polishing techniques. Exogenesis Corporation, using its new and proprietary Accelerated Neutral Atom Beam (ANAB) technology, is able to remove nano-scale surface damage and particle contamination leaving many material surfaces with roughness typically around one Angstrom. This surface defect mitigation via ANAB processing can be shown to increase performance properties of high intensity optical materials. This paper describes the ANAB technology and summarizes smoothing results for calcium fluoride laser windows. It further correlates laser damage threshold improvements with the smoothing produced by ANAB surface treatment. All ANAB processing was performed at Exogenesis Corporation using an nAccel100TM Accelerated Particle Beam processing tool. All surface measurement data for the paper was produced via AFM analysis on a Park Model XE70 AFM, and all laser damage testing was performed at Spica Technologies, Inc. Exogenesis Corporation's ANAB processing technology is a new and unique surface modification technique that has demonstrated to be highly effective at correcting nano-scale surface defects. ANAB is a non-contact vacuum process comprised of an intense beam of accelerated, electrically neutral gas atoms with average energies of a few tens of electron volts. The ANAB process does not apply mechanical forces associated with traditional polishing techniques. ANAB efficiently removes surface

  2. Cuticular surface damage of Ascaridia galli adult worms treated with Veitchia merrillii betel nuts extract in vitro.

    Science.gov (United States)

    Balqis, Ummu; Hambal, Muhammad; Rinidar; Athaillah, Farida; Ismail; Azhar; Vanda, Henni; Darmawi

    2017-07-01

    The objective of this research was to in vitro evaluate the cuticular surface damage of Ascaridia galli adult worms treated with ethanolic extract of betel nuts Veitchia merrillii . Phytochemical screening was done using FeCl 3 , Wagner and Dragendorff reagents, NaOH, MgHCl, and Liebermann-Burchard reaction test. Amount of 16 worms were segregated into four groups with three replicates. Four worms of each group submerged into phosphate buffered saline, 25 mg/ml, and 75 mg/ml crude ethanolic extract of V. merrillii , and 15 mg/ml albendazole. The effect of these extract was observed 40 h after incubation as soon as worms death. The worms were sectioned transversally and were explored for any cuticular histopathological changes in their body surface under microscope. We found that the ethanolic extract of V. merrillii betel nuts contains tannins, alkaloids, flavonoids, triterpenoids, and saponins. The ethanolic extract of betel nuts V. merrillii induces surface alterations caused cuticular damage of A. galli adult worms. We concluded that ethanolic extract of betel nuts V. merrillii possess anthelmintic activity caused cuticular damage of A. galli adult worms.

  3. Comparison of laser-induced surface damage density measurements with small and large beams: toward representativeness

    International Nuclear Information System (INIS)

    Lamaignere, Laurent; Dupuy, Gabriel; Donval, Thierry; Grua, Pierre; Bercegol, Herve

    2011-01-01

    Pulsed laser damage density measurements obtained with diverse facilities are difficult to compare, due to the interplay of numerous parameters, such as beam area and pulse geometry, which, in operational large beam conditions, are very different from laboratory measurements. This discrepancy could have a significant impact; if so, one could not even pretend that laser damage density control is a real measurement process. In this paper, this concern is addressed. Tests with large beams of centimeter size on a high-power laser facility have beam performed according to a parametric study and are compared to small beam laboratory tests. It is shown that laser damage densities obtained with large and small beams are equal, within calculated error bars.

  4. Experimental Study of Plasma-Surface Interaction and Material Damage Relevant to ITER Type I Elms

    International Nuclear Information System (INIS)

    Makhlai, V.A.; Bandura, A.N.; Byrka, O.V. and others; Landman, I.; Neklyudov, I.M.

    2006-01-01

    The paper presents experimental investigations of main features of plasma surface interaction and energy transfer to the material surface in dependence on plasma heat loads. The experiments were performed with QSPA repetitive plasma pulses of the duration of 0.25 ms and the energy density up to 2.5 MJ/m 2 . Surface morphology of the targets exposed to QSPA plasma screams is analyzed. Relative contribution of the Lorentz force and plasma pressure gradient to the resulting surface profile is discussed. development of cracking on the tungsten surface and swelling of the surface are found to be in strong dependence on initial temperature of the target

  5. Abbreviated machining schedule for fabricating beryllium parts free of surface damage

    International Nuclear Information System (INIS)

    Beitscher, S.; Capes, J.F.; Leslie, W.W.; Luckow, J.R.; Riegel, R.L.

    1979-01-01

    This study was performed to develop a more economical method of machining damage-free beryllium components at Rocky Flats. The present method involves a 9-pass schedule of lathe turning followed by a chemical etch. Prototype beryllium hemispherical shell parts and cylindrical tensile specimens machined to simulate the parts were utilized in this study. The main investigative methods used to evaluate the amount of machining damage were metallography and tensile tests. It was found that damage-free parts could be produced by carefully controlled machining if the number of machining passes was reduced to 4 or even 3, if followed by the standard etching treatment. These findings were made on Select S-65 grade beryllium, and probably apply to other common grades of powder source beryllium but not necessarily to ingot-source beryllium. It is recommended that the 4-pass schedule becomes the standard method to produce damage-free beryllium derived from powder. Significant savings in time, labor, and equipment can be realized by this change in method without decreasing the quality of the product

  6. Earliness, leaf surface wax and sugar content predict varietal differences for thrips damage in cabbage

    NARCIS (Netherlands)

    Voorrips, R.E.; Steenhuis-Broers, M.M.; Tiemens-Hulscher, M.; Lammerts Van Bueren, E.

    2010-01-01

    When cabbage is cultivated for storage in the Netherlands, it is usually harvested around mid-October. This type of cabbage crop may be severely damaged by thrips (Thrips tabaci). The thrips population on the plants and the more severe symptoms develop mostly during September and October. Also

  7. Effect of temperature on surface error and laser damage threshold for self-healing BK7 glass.

    Science.gov (United States)

    Wang, Chu; Wang, Hongxiang; Shen, Lu; Hou, Jing; Xu, Qiao; Wang, Jian; Chen, Xianhua; Liu, Zhichao

    2018-03-20

    Cracks caused during the lapping and polishing process can decrease the laser-induced damage threshold (LIDT) of the BK7 glass optical elements, which would shorten the lifetime and limit the output power of the high-energy laser system. When BK7 glass is heated under appropriate conditions, the surface cracks can exhibit a self-healing phenomenon. In this paper, based on thermodynamics and viscous fluid mechanics theory, the mechanisms of crack self-healing are explained. The heat-healing experiment was carried out, and the effect of water was analyzed. The multi-spatial-frequency analysis was used to investigate the effect of temperature on surface error for self-healing BK7 glass, and the lapped BK7 glass specimens before and after heat healing were detected by an interferometer and atomic force microscopy. The low-spatial-frequency error was analyzed by peak to valley and root mean square, the mid-spatial-frequency error was analyzed by power spectral density, and the high-spatial-frequency error was analyzed by surface roughness. The results showed that the optimal heating temperature for BK7 was 450°C, and when the heating temperature was higher than the glass transition temperature (555°C), the surface quality decreased a lot. The laser damage test was performed, and the specimen heated at 450°C showed an improvement in LIDT.

  8. Use of computed tomography slices 3D-reconstruction as a powerful tool to improve manufacturing processes on aeroengine components

    International Nuclear Information System (INIS)

    Castellan, C.; Dastarac, D.

    2000-01-01

    TURBOMECA has been using computed tomography for several years as an inner-health analysis powerful tool for engine components. From 2D slices of the examined part, detailed information about lacks or inclusions could easily be extracted. But, measurements on internal features were quickly required because no other NDT methods were able to do it. CT has thus logically become a powerful 2D dimensional measuring tool. Recently, with new software and the latest computers able to deal with huge files, CT has become a powerful 3D digitization tool and now, TOMO ADOUR can offer a complete solution for reverse engineering of complex parts. Several months ago, TURBOMECA introduced CT into many development, validation and industrialization processes and has demonstrated how to take corrective actions to process deviation on their aeroengine components by: extracting the nonexisting CAD model of a part, generating CAD compatible data to check dimensional conformity and, eventually correct design misfits or manufacturing drifts, highlighting the metallurgical health of first article parts, making the decision of repairing the defining the appropriate method, generating a file (.STL) to build a rapid prototype or a file to pilot tool parts for machining, calculating physical properties such as behavior or flow analysis on a 'real' model. The image also allows a drawing to be made of a part that was originally produced by a supplier or competitor. This paper will be illustrated with a large number of examples

  9. Application of laser cladding to the aeroengine component. Koku engine buhin eno laser nikumori yosetsu no tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Morita, A [Ishikawajima-Harima Heavy Industries, Co. Ltd., Tokyo (Japan)

    1991-08-01

    Keeping the pace with recent development and application of laser cladding, hard-facing is used more frequently on turbine blades made of superalloys used in aeroengines. This paper explains the basic principles and features of laser hard-facing technique, welding parameters, and examples of practical use. Examples of practical use include application to turbine blades used in ALF502R-5 turbo fan engines for commuter aircraft and high-pressure turbine blades used in RB211 turbo fan engines for large passenger aircraft. In the former engine, improvement of abrasion resistance was intended at the shroud section where blades are in contact with each other, for which inconel was used as the base material and CO-group alloy as the welding material. The welding used a powder supply system with a laser generator oscillating CO{sub 2} at 5 kW and employing a beam collecting mirror plus scanner to attain a beam covering wider width. Faces with higher performance were obtained than by the conventional TIG welding, and the finishing time was decreased largely. 2 refs., 9 figs., 3 tabs.

  10. Recent progress in fan and compressor for aeroengine. Koku engine yo fan asshukuki no saikin no gijutsu shinpo

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Y [National Aerospace Lab., Chofu, Tokyo (Japan)

    1994-03-10

    As the main components of the aeroengine, the fan and compressor reach to extremely high level stage technologically. Also at present when about 50 years passed after the jet engine was applied in practice, however, an effort for a modification is being continued, and furthermore even in the 1990s, the engines that adopted the new technologies are in succession being put in practical application. New engines in the 1990s are being applied in practice by adopting the study results on fan and compressor from the 1970s to the 1980s. Because, which way the future fan and compressor of the aircraft will go to has a relation with an aircraft trend from now on, and even in the 2000s the high subsonic speed aircrafts will be a center of the private air planes. The engine of high subsonic speed aircraft in the next generation will become an ultrahigh bypass ratio engine, the thrust efficiency is raised and noise is lowered, by lowering a fan pressure ratio and by increasing an air flow quantity compared with the current high bypass ratio turbofan engine. 16 figs.

  11. The effect of surface corrosion damage on the fatigue life of 6061-T6 aluminum alloy extrusions

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Matthew; Eason, Paul D.; Özdeş, Hüseyin; Tiryakioğlu, Murat, E-mail: m.tiryakioglu@unf.edu

    2017-04-06

    An investigation was performed where 6061-T6 extrusions were exposed to a 3.5% NaCl solution at pH 2 for 2 days and 24 days to create distinct surface flaws. The effect of these flaws on the rotating beam fatigue life was then investigated and analyzed by using Wöhler curves, Weibull statistics and scanning electron microscopy (SEM). It was determined that corrosion damage reduced the fatigue life significantly and specimens corroded for both 2-days and 24-days exhibited similar fatigue lives. Statistical analyses showed that fatigue life of all three datasets followed the 3-parameter Weibull distribution and the difference between the fatigue lives of two corroded datasets was statistically insignificant. Analysis of fracture surfaces showed that sizes of pits that led to fatigue crack initiation were very different in the two corroded datasets. Implications of the similarity in fatigue lives despite disparity in surface condition are discussed in detail in the paper.

  12. Simultaneous impact of neutron irradiation and sputtering on the surface structure of self–damaged ITER–grade tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Belyaeva, A. I., E-mail: aibelyaeva@mail.ru; Savchenko, A. A. [National Technical University “Kharkov Politechnical Institute”, Kharkov, 61002 (Ukraine); Galuza, A. A.; Kolenov, I. V. [Institute of Electrophysics and Radiation Technologies, National Academy of Science of Ukraine, Kharkov, 61024 (Ukraine)

    2014-07-15

    Simultaneous effects of neutron irradiation and long–term sputtering on the surface relief of ITER–grade tungsten were studied. The effects of neutron–induced displacement damage have been simulated by irradiation of tungsten target with W{sup 6+} ions of 20 MeV energy. Ar{sup +} ions with energy 600 eV were used as imitation of charge exchange atoms in ITER. The surface relief was studied after each sputtering act. The singularity in the WJ–IG surface relief was ascertained experimentally at the first time, which determines the law of roughness extension under sputtering. As follows from the experimental data, the neutron irradiation has not to make a decisive additional contribution in the processes developing under impact of charge exchange atoms only.

  13. Surface damage studies of ETFE polymer bombarded with low energy Si ions (≤100 keV)

    International Nuclear Information System (INIS)

    Minamisawa, Renato Amaral; Almeida, Adelaide De; Budak, Satilmis; Abidzina, Volha; Ila, Daryush

    2007-01-01

    Surface studies of ethylenetetrafluoroethylene (ETFE), bombarded with Si in a high-energy tandem Pelletron accelerator, have recently been reported. Si ion bombardment with a few MeV to a few hundred keV energies was shown to be sufficient to produce damage on ETFE film. We report here the use of a low energy implanter with Si ion energies lower than 100 keV, to induce changes on ETFE films. In order to determine the radiation damage, ETFE bombarded films were simulated with SRIM software and analyzed with optical absorption photometry (OAP), Raman and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy to show quantitatively the physical and chemical property changes. Carbonization occurs following higher dose implantation, and hydroperoxides were formed following dehydroflorination of the polymer

  14. Mitigation technologies for damage induced by pressure waves in high-power mercury spallation neutron sources (1). Material surface improvement

    International Nuclear Information System (INIS)

    Naoe, Takashi; Futakawa, Masatoshi; Wakui, Takashi; Kogawa, Hiroyuki; Shoubu, Takahisa; Takeuchi, Hirotsugu; Kawai, Masayoshi

    2008-01-01

    Liquid-mercury target systems for MW-class spallation neutron sources are being developed in the world. Proton beams will be used to induce the spallation reaction. At the moment the proton beam hits the target, pressure waves are generated in the mercury because of the abrupt heat deposition. The pressure waves interact with the target vessel leading to negative pressure that may cause cavitation along the vessel wall. Localized impacts by microjets and/or shock waves that are caused by cavitation bubble collapse impose pitting damage on the vessel wall. Bubble collapse behavior was observed by using a high-speed video camera, as well as simulated numerically. Localized impact due to cavitation bubble collapse was quantitatively estimated through comparison between numerical simulation and experiment. A novel surface treatment technique that consists of carburizing and nitriding processes was developed and the treatment condition was optimized to mitigate the pitting damage due to localized impacts. (author)

  15. Detection of a milling-induced surface damage by the magnetic Barkhausen noise

    Czech Academy of Sciences Publication Activity Database

    Stupakov, Alexandr; Neslušan, M.; Perevertov, Oleksiy

    2016-01-01

    Roč. 410, Jul (2016), 198-209 ISSN 0304-8853 R&D Projects: GA ČR GB14-36566G; GA ČR GA13-18993S Institutional support: RVO:68378271 Keywords : Barkhausen noise * surface field measurement * magnetization waveformcontrol * hard turning * surface integrity Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 2.630, year: 2016

  16. Cell surface damage and morphological changes in Oenococcus oeni after freeze-drying and incubation in synthetic wine.

    Science.gov (United States)

    Bravo-Ferrada, Bárbara Mercedes; Gonçalves, Sónia; Semorile, Liliana; Santos, Nuno C; Brizuela, Natalia; Elizabeth Tymczyszyn, E; Hollmann, Axel

    2018-04-28

    The aim of the present study was to evaluate the effects of freeze-drying in the presence of trehalose as a cryoprotectant, followed by incubation in synthetic wine, on surface damage, viability and l-malic acid consumption of the oenological strain Oenococcus oeni UNQOe 73.2. After freeze-drying, no significant differences were observed in the number of viable cells (for both acclimated and non-acclimated cultures) respect to the fresh culture. In contrast, loss of viability was observed after wine incubation for 24 h, being acclimated freeze-dried cells the best conditions for this. After the preservation process, small changes in cell morphology were observed by Atomic Force Microscopy (AFM). The Zeta potential and AFM showed that 24 h of wine incubation was enough to induce several cell surface modifications. Plate count data allowed us to establish that surface damage is an important factor for loss of viability, regardless of the acclimation treatment. Although the number of surviving O. oeni cells decreased dramatically after incubation in synthetic wine for 15 days, the consumption of l-malic acid was higher than 70%, with freeze-dried cells showing a better performance than fresh cultures. These results demonstrate that O. oeni freeze-dried cultures could be applied to direct wine inoculation, to conduct malolactic fermentation, maintaining its technological properties and reducing the time and costs of the winemaking process. Copyright © 2018. Published by Elsevier Inc.

  17. Effects of prior surface damage on high-temperature oxidation of Fe-, Ni-, and Co-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Peter Julian [ORNL; Lowe, Tracie M [ORNL; Pint, Bruce A [ORNL

    2009-01-01

    Multi-component metallic alloys have been developed to withstand high-temperature service in corrosive environments. Some of these applications, like exhaust valve seats in internal combustion engines, must also resist sliding, impact, and abrasion. The conjoint effects of temperature, oxidation, and mechanical contact can result in accelerated wear and the formation of complex surface layers whose properties differ from those of the base metal and the oxide scale that forms in the absence of mechanical contact. The authors have investigated the effects of prior surface damage, produced by scratch tests, on the localized reformation of oxide layers. Three high-performance commercial alloys, based on iron, nickel, and cobalt, were used as model materials. Thermogravimetric analysis (TGA) was used to determine their static oxidation rates at elevated temperature (850o C). A micro-abrasion, ball-cratering technique was used to measure oxide layer thickness and to compare it with TGA results. By using taper-sectioning techniques and energy-dispersive elemental mapping, a comparison was made between oxide compositions grown on non-damaged surfaces and oxides that formed on grooves produced by a diamond stylus. Microindentation and scratch hardness data revealed the effects of high temperature exposure on both the substrate hardness and the nature of oxide scale disruption. There were significant differences in elemental distribution between statically-formed oxides and those that formed on scratched regions

  18. Transient thermal driven bubble's surface and its potential ultrasound-induced damage

    Science.gov (United States)

    Movahed, Pooya; Freund, Jonathan B.

    2017-11-01

    Ultrasound-induced bubble activity in soft tissues is well-known to be a potential injury mechanism in therapeutic ultrasound treatments. We consider damage by transient thermal effects, including a hypothetical mechanism based on transient thermal phenomena, including viscous dissipation. A spherically symmetric compressible Navier-Stokes discretization is developed to solve the full governing equations, both inside and outside of the bubble, without the usual simplifications in the Rayleigh-Plesset bubble dynamics approach. Equations are solved in the Lagrangian framework, which provides a sharp and accurate representation of the interface as well as the viscous dissipation and thermal transport effects, which preclude reduction to the usual Rayleigh-Plesset ordinary differential equation. This method is used to study transient thermal effects at different frequencies and pressure amplitudes relevant to therapeutic ultrasound treatments. High temperatures achieved in the surrounding medium during the violent bubble collapse phase due to the viscous dissipation in the surrounding medium and thermal conduction from the bubble are expected to cause damage. This work was supported by NIH NIDDK Grant P01-DK043881.

  19. An Improved Method of Mitigating Laser Induced Surface Damage Growth in Fused Silica Using a Rastered, Pulsed CO2 Laser

    Energy Technology Data Exchange (ETDEWEB)

    Bass, I L; Guss, G M; Nostrand, M J; Wegner, P L

    2010-10-21

    A new method of mitigating (arresting) the growth of large (>200 m diameter and depth) laser induced surface damage on fused silica has been developed that successfully addresses several issues encountered with our previously-reported large site mitigation technique. As in the previous work, a tightly-focused 10.6 {micro}m CO{sub 2} laser spot is scanned over the damage site by galvanometer steering mirrors. In contrast to the previous work, the laser is pulsed instead of CW, with the pulse length and repetition frequency chosen to allow substantial cooling between pulses. This cooling has the important effect of reducing the heat-affected zone capable of supporting thermo-capillary flow from scale lengths on the order of the overall scan pattern to scale lengths on the order of the focused laser spot, thus preventing the formation of a raised rim around the final mitigation site and its consequent down-stream intensification. Other advantages of the new method include lower residual stresses, and improved damage threshold associated with reduced amounts of redeposited material. The raster patterns can be designed to produce specific shapes of the mitigation pit including cones and pyramids. Details of the new technique and its comparison with the previous technique will be presented.

  20. A New Quantitative Method for the Non-Invasive Documentation of Morphological Damage in Paintings Using RTI Surface Normals

    Directory of Open Access Journals (Sweden)

    Marcello Manfredi

    2014-07-01

    Full Text Available In this paper we propose a reliable surface imaging method for the non-invasive detection of morphological changes in paintings. Usually, the evaluation and quantification of changes and defects results mostly from an optical and subjective assessment, through the comparison of the previous and subsequent state of conservation and by means of condition reports. Using quantitative Reflectance Transformation Imaging (RTI we obtain detailed information on the geometry and morphology of the painting surface with a fast, precise and non-invasive method. Accurate and quantitative measurements of deterioration were acquired after the painting experienced artificial damage. Morphological changes were documented using normal vector images while the intensity map succeeded in highlighting, quantifying and describing the physical changes. We estimate that the technique can detect a morphological damage slightly smaller than 0.3 mm, which would be difficult to detect with the eye, considering the painting size. This non-invasive tool could be very useful, for example, to examine paintings and artwork before they travel on loan or during a restoration. The method lends itself to automated analysis of large images and datasets. Quantitative RTI thus eases the transition of extending human vision into the realm of measuring change over time.

  1. Wear surface damage of a Stainless Steel EN 3358 aeronautical component subjected to sliding

    Directory of Open Access Journals (Sweden)

    Ferdinando Felli

    2013-01-01

    Full Text Available The present paper describes the failure analysis of an aircraft component subjected to several episodes of in service failure, resulted in loss of the aircraft safety. Modern aircrafts are provided with mechanical systems which have the task to open not pressurized hatches during landing. The components of such systems are subject to considerable mechanical stresses in harsh environment (presence of moisture and pollutants, significant and sudden temperature variations. The system is constituted by a sliding piston, a related nipple and by a locking system consisting of 4 steel spheres which are forced into a countersink machined on the piston when the hatches is open. The whole system is activated by a preloaded spring. The machined parts, nipple and piston, are made of EN3358 steel (X3CrNiMo13-8-2, a precipitation hardening stainless steel with very low content of carbon often used in the aerospace. The samples provided by the manufacturer present different types of damage all referable to phenomena relative to the sliding of the piston inside the nipple. The present paper describes the different damage observed and the microstructure of the material, then are reported the results obtained from the characterization of the material of the samples by means of optical and electronic microscopy, carried out to define the mechanisms involved in the system seizure. In order to define the primary cause of failure and to propose solutions to be adopted, also analyzing the criticality of using this PH stainless steel for this application, the results of different tests were compared with system design and working data.

  2. Surface damage of 316 stainless steel irradiated with 4He+ to high doses

    International Nuclear Information System (INIS)

    Kaminsky, M.; Das, S.K.

    1978-01-01

    Surface blistering of niobium by implantation with helium ions in the 9 to 15 keV range was investigated. The apparent disappearance of blisters at sufficiently high doses was believed to be an equilibrium effect. To determine whether high temperature annealing causes the equilibrium condition, stainless steel-316 samples were irradiated at a constant 450 0 C. Results are presented

  3. Surface damages of polycrystalline W and La2O3-doped W induced by high-flux He plasma irradiation

    Science.gov (United States)

    Liu, Lu; Li, Shouzhe; Liu, Dongping; Benstetter, Günther; Zhang, Yang; Hong, Yi; Fan, Hongyu; Ni, Weiyuan; Yang, Qi; Wu, Yunfeng; Bi, Zhenhua

    2018-04-01

    In this study, polycrystalline tungsten (W) and three oxide dispersed strengthened W with 0.1 vol %, 1.0 vol % and 5.0 vol % lanthanum trioxide (La2O3) were irradiated with low-energy (200 eV) and high-flux (5.8 × 1021 or 1.4 × 1022 ions/m2ṡs) He+ ions at elevated temperature. After He+ irradiation at a fluence of 3.0 × 1025/m2, their surface damages were observed by scanning electron microscopy, energy dispersive spectroscopy, scanning electron microscopy-electron backscatter diffraction, and conductive atomic force microscopy. Micron-sized holes were formed on the surface of W alloys after He+ irradiation at 1100 K. Analysis shows that the La2O3 grains doped in W were sputtered preferentially by the high-flux He+ ions when compared with the W grains. For irradiation at 1550 K, W nano-fuzz was formed at the surfaces of both polycrystalline W and La2O3-doped W. The thickness of the fuzz layers formed at the surface of La2O3-doped W is 40% lower than the one of polycrystalline W. The presence of La2O3 could suppress the diffusion and coalescence of He atoms inside W, which plays an important role in the growth of nanostructures fuzz.

  4. Composite adaptive control of belt polishing force for aero-engine blade

    Science.gov (United States)

    Zhsao, Pengbing; Shi, Yaoyao

    2013-09-01

    The existing methods for blade polishing mainly focus on robot polishing and manual grinding. Due to the difficulty in high-precision control of the polishing force, the blade surface precision is very low in robot polishing, in particular, quality of the inlet and exhaust edges can not satisfy the processing requirements. Manual grinding has low efficiency, high labor intensity and unstable processing quality, moreover, the polished surface is vulnerable to burn, and the surface precision and integrity are difficult to ensure. In order to further improve the profile accuracy and surface quality, a pneumatic flexible polishing force-exerting mechanism is designed and a dual-mode switching composite adaptive control(DSCAC) strategy is proposed, which combines Bang-Bang control and model reference adaptive control based on fuzzy neural network(MRACFNN) together. By the mode decision-making mechanism, Bang-Bang control is used to track the control command signal quickly when the actual polishing force is far away from the target value, and MRACFNN is utilized in smaller error ranges to improve the system robustness and control precision. Based on the mathematical model of the force-exerting mechanism, simulation analysis is implemented on DSCAC. Simulation results show that the output polishing force can better track the given signal. Finally, the blade polishing experiments are carried out on the designed polishing equipment. Experimental results show that DSCAC can effectively mitigate the influence of gas compressibility, valve dead-time effect, valve nonlinear flow, cylinder friction, measurement noise and other interference on the control precision of polishing force, which has high control precision, strong robustness, strong anti-interference ability and other advantages compared with MRACFNN. The proposed research achieves high-precision control of the polishing force, effectively improves the blade machining precision and surface consistency, and

  5. Surface modification of amorphous nanosilica particles suppresses nanosilica-induced cytotoxicity, ROS generation, and DNA damage in various mammalian cells

    International Nuclear Information System (INIS)

    Yoshida, Tokuyuki; Yoshioka, Yasuo; Matsuyama, Keigo; Nakazato, Yasutaro; Tochigi, Saeko; Hirai, Toshiro; Kondoh, Sayuri; Nagano, Kazuya; Abe, Yasuhiro; Kamada, Haruhiko; Tsunoda, Shin-ichi; Nabeshi, Hiromi; Yoshikawa, Tomoaki; Tsutsumi, Yasuo

    2012-01-01

    Highlights: ► There is increasing concern regarding the potential health risks of nanomaterials. ► We evaluated the effect of surface properties of nanomaterials on cellular responses. ► We showed that the surface properties play an important in determining its safety. ► These data provide useful information for producing safer nanomaterials. -- Abstract: Recently, nanomaterials have been utilized in various fields. In particular, amorphous nanosilica particles are increasingly being used in a range of applications, including cosmetics, food technology, and medical diagnostics. However, there is concern that the unique characteristics of nanomaterials might induce undesirable effects. The roles played by the physical characteristics of nanomaterials in cellular responses have not yet been elucidated precisely. Here, by using nanosilica particles (nSPs) with a diameter of 70 nm whose surface was either unmodified (nSP70) or modified with amine (nSP70-N) or carboxyl groups (nSP70-C), we examined the relationship between the surface properties of nSPs and cellular responses such as cytotoxicity, reactive oxygen species (ROS) generation, and DNA damage. To compare the cytotoxicity of nSP70, nSP70-N, or nSP70-C, we examined in vitro cell viability after nSP treatment. Although the susceptibility of each cell line to the nSPs was different, nSP70-C and nSP70-N showed lower cytotoxicity than nSP70 in all cell lines. Furthermore, the generation of ROS and induction of DNA damage in nSP70-C- and nSP70-N-treated cells were lower than those in nSP70-treated cells. These results suggest that the surface properties of nSP70 play an important role in determining its safety, and surface modification of nSP70 with amine or carboxyl groups may be useful for the development of safer nSPs. We hope that our results will contribute to the development of safer nanomaterials.

  6. Damage caused by a nanosecond UV laser on a heated copper surface

    Energy Technology Data Exchange (ETDEWEB)

    Henč-Bartolić, V., E-mail: visnja.henc@fer.hr [University of Zagreb, Faculty of Electrical Engineering and Computing, Unska 3, 10000 Zagreb (Croatia); Bončina, T. [University of Maribor, Faculty of Mechanical Engineering, Smetanova 17, 2000 Maribor (Slovenia); Jakovljević, S., E-mail: suzana.jakovljevic@fsb.hr [University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, Ivana Lučića 5, 10002 Zagreb (Croatia); Panjan, P. [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Zupanič, F. [University of Maribor, Faculty of Mechanical Engineering, Smetanova 17, 2000 Maribor (Slovenia)

    2016-08-15

    Highlights: • A Cu-plate was exposed to nanosecond UV laser with max. energy 1.1 J/cm{sup 2}. • Surface topography was studied on the cold and heated copper plate. • At room temperature, a crater formed, the melt was ejected from it. • Capillary waves formed in the vicinity of the crater at 360 °C. - Abstract: This work studied the effect of thin copper plate temperature on its surface morphology after irradiation using a pulsed nanosecond UV laser. The surface characteristics were investigated using scanning electron microscopy, energy dispersive X-ray spectroscopy, focused ion beam and stylus profilometry. When a target was at room temperature, a crater and the radial flow of molten Cu from the crater was observed. When the thin target was warm (about 360 °C ± 20 °C), a crater was smaller, and quasi-semicircular waves with the periodicity of around 3 μm appeared in its vicinity. The origin of the waves is Marangoni effect, causing thermocapillary waves, which in same occasions had a structure of final states of chaos in Rayleigh–Bénard convection.

  7. Surface modification of basalt with silane coupling agent on asphalt mixture moisture damage

    Energy Technology Data Exchange (ETDEWEB)

    Min, Yahong; Fang, Ying; Huang, Xiaojun; Zhu, Yinhui; Li, Wensheng [College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 (China); Yuan, Jianmin [College of Materials Engineering, Hunan University, Changsha, 410082 (China); Tan, Ligang [College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082 (China); Wang, Shuangyin [State Key Laboratory of Chem/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 (China); Wu, Zhenjun, E-mail: wooawt@163.com [College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 (China)

    2015-08-15

    Graphical abstract: - Highlights: • A new silane coupling agent was synthesized based on KH570. • Basalt surface was modified using the new silane coupling agent. • Chemical bond between basalt and the new silane coupling agent was formed. • Asphalt mixture which used modified basalt show superior water stability. - Abstract: A new silane coupling agent was synthesized based on γ-(methacryloyloxy) propyltrimethoxysilane (KH570). The surface of basalt rocks was modified by KH570 and the new silane coupling agent (NSCA), and the interfacial interaction between silane coupling agent and basalt was also studied. Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis showed that the silane coupling agent molecule bound strongly with basalt rocks. Scanning electronic microscopy (SEM) observation showed that a thin layer of coupling agent was formed on the surface of modified basalt. The boiling test and immersion Marshall test confirmed that the moisture sensitivity of basalt modified with the new silane coupling agent increased more significantly than that untreated and treated with KH570. The Retained Marshall Strength of basalt modified with the new coupling agent increased from 71.74% to 87.79% compared with untreated basalt. The results indicated that the new silane coupling agent played an important role in improving the interfacial performance between basalt and asphalt.

  8. Susceptibility to scratch surface damage of wollastonite- and talc-containing polypropylene micrometric composites

    International Nuclear Information System (INIS)

    Hadal, R.; Dasari, A.; Rohrmann, J.; Misra, R.D.K.

    2004-01-01

    The paper describes the effect of wollastonite and talc on the scratch deformation behavior of low and high crystallinity polypropylenes under identical test conditions. The vertical resolution of atomic force microscopy and lateral resolution of scanning electron microscopy is utilized to examine the characteristics of scratch damage. Contrary to the expectations that high crystallinity and stiffness of polypropylene composites should increase resistance to scratch deformation, the susceptibility to mechanical deformation depends on bonding of mineral particles to the polymer matrix. Scratch deformed regions in neat polypropylenes were free of voids and grooves, while reinforced-polypropylenes exhibited voids and debonding/detachment of filler particles. The severity of plastic deformation in reinforced polypropylenes is a function of debonding/detachment of mineral particles, which is comparatively more for talc-reinforced polypropylenes than wollastonite-reinforced polypropylenes because of the layered structure of talc that encourages delamination. Usage of coating and coupling agents improved the resistance to scratch deformation by promoting adhesion and bonding between the reinforcement and matrix

  9. Diagnosis of the surface layer damage in a 1960s reinforced concrete building

    Directory of Open Access Journals (Sweden)

    S.L. Pagliolico

    2014-01-01

    Full Text Available This work aimed to determine the degradation causes of the Palace of Public Works located in S. Giovanni square in Turin (Piedmont, Italy. The samples collected from the surface layer were characterized by means of scanning electron microscopy (SEM, X-ray diffraction (XRD, thermogravimetric coupled with differential thermal analysis (TG-DTA, mercury intrusion porosimetry measurements (MIP and phenolphthalein test. Metallographic and elemental analyses were also carried out on the steel reinforcing bars. An exhaustive picture of the main causes of deterioration was drawn in order to design the intervention of rehabilitation.

  10. Surface structural damage study in cortical bone due to medical drilling.

    Science.gov (United States)

    Tavera R, Cesar G; De la Torre-I, Manuel H; Flores-M, Jorge M; Hernandez M, Ma Del Socorro; Mendoza-Santoyo, Fernando; Briones-R, Manuel de J; Sanchez-P, Jorge

    2017-05-01

    A bone's fracture could be produced by an excessive, repetitive, or sudden load. A regular medical practice to heal it is to fix it in two possible ways: external immobilization, using a ferule, or an internal fixation, using a prosthetic device commonly attached to the bone by means of surgical screws. The bone's volume loss due to this drilling modifies its structure either in the presence or absence of a fracture. To observe the bone's surface behavior caused by the drilling effects, a digital holographic interferometer is used to analyze the displacement surface's variations in nonfractured post-mortem porcine femoral bones. Several nondrilled post-mortem bones are compressed and compared to a set of post-mortem bones with a different number of cortical drillings. During each compression test, a series of digital interferometric holograms were recorded using a high-speed CMOS camera. The results are presented as pseudo 3D mesh displacement maps for comparisons in the physiological range of load (30 and 50 lbs) and beyond (100, 200, and 400 lbs). The high resolution of the optical phase gives a better understanding about the bone's microstructural modifications. Finally, a relationship between compression load and bone volume loss due to the drilling was observed. The results prove that digital holographic interferometry is a viable technique to study the conditions that avoid the surgical screw from loosening in medical procedures of this kind.

  11. Separation of surface, subsurface and volume fatigue damage effects in AISI 348 steel for power plant applications

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Martin; Nowak, David; Walther, Frank [Technical Univ. Dortmund (Germany). Dept. of Materials Test Engineering (WPT); Starke, Peter [Saarland Univ., Saarbruecken (Germany). Chair of Non-Destructive Testing and Quality Assurance; Boller, Christian [Saarland Univ., Saarbruecken (Germany). Chair of Non-Destructive Testing and Quality Assurance; Fraunhofer IZFP, Saarbruecken (Germany)

    2016-08-01

    A wide range of industries including energy, chemistry, pharmacy, textiles, food and drink, pulp and paper, etc. is using stainless steels. Metastable austenitic steels such as used in power plants and chemical industry are subjected to cyclic mechanical and thermal loading in air as well as under the influence of corrosive media. This paper provides an overview on different nondestructive and electrochemical measurement techniques, which allow differentiating fatigue damage effects in total strain controlled multiple and constant amplitude tests with respect to damage appearance on surface, in subsurface area as well as in volume of specimens or components microstructure. In addition to conventional mechanical stress-strain hysteresis curves, electrical resistance, magnetic and open circuit potential measurements have been applied to characterize the cyclic deformation behavior of the metastable austenitic steel AISI 348 (X10CrNiNb18-9) in laboratory air and in distilled water. Based on these results obtained, the paper provides an outlook on the possibility for an efficient (remaining) fatigue life evaluation approach, which is adapted to the needs of the application areas.

  12. Surface damage on polycrystalline β-SiC by xenon ion irradiation at high fluence

    Science.gov (United States)

    Baillet, J.; Gavarini, S.; Millard-Pinard, N.; Garnier, V.; Peaucelle, C.; Jaurand, X.; Duranti, A.; Bernard, C.; Rapegno, R.; Cardinal, S.; Escobar Sawa, L.; De Echave, T.; Lanfant, B.; Leconte, Y.

    2018-05-01

    Polycrystalline β-silicon carbide (β-SiC) pellets were prepared by Spark Plasma Sintering (SPS). These were implanted at room temperature with 800 keV xenon at ion fluences of 5.1015 and 1.1017 cm-2. Microstructural modifications were studied by electronic microscopy (TEM and SEM) and xenon profiles were determined by Rutherford Backscattering Spectroscopy (RBS). A complete amorphization of the implanted area associated with a significant oxidation is observed for the highest fluence. Large xenon bubbles formed in the oxide phase are responsible of surface swelling. No significant gas release has been measured up to 1017 at.cm-2. A model is proposed to explain the different steps of the oxidation process and xenon bubbles formation as a function of ion fluence.

  13. Micro- and nano-scale damage on the surface of W divertor component during exposure to high heat flux loads with He

    International Nuclear Information System (INIS)

    Li, C.; Greuner, H.; Zhao, S.X.; Böswirth, B.; Luo, G.N.; Zhou, X.; Jia, Y.Z.; Liu, X.; Liu, W.

    2015-01-01

    Micro- and nano-scale surface damage on a W divertor component sample exposed to high heat flux loads generated with He atoms has been investigated through SEM, EBSD, AFM and FIB-SEM. The component sample was supplied by the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) and AT&M company, China, and the loading experiment was performed in the GLADIS facility at IPP Garching, Germany. Two typical damage structures were observed on the surface: the first one is characterized by obvious blisters and some grooves formed from ruptured blisters, and the other one is a kind of porous structure accompanying with at least ∼25 nm surface material loss. As the grain orientation is further away from , the damage morphology gradually changes from the former structure to the latter. The possible damage mechanism is discussed. - Highlights: • Two damage structures were observed on W component surface under He beam heating. • Blistering was more obvious in near grains. • Porous structure appeared in the grains away from . • A loose layer caused by He aggregation was formed in near-surface region.

  14. Assessment of DNA damages caused by exposure of bacterial cells and spores to the Mars surface environment

    Science.gov (United States)

    Fajardo-Cavazos, Patricia; Schuerger, Andrew; Robles-Martinez, Jose; Douki, Thierry; Nicholson, Wayne

    Joint NASA and ESA missions are planned for the next decade to investigate the possibility of present or past life on Mars [1]. Evidence of extraterrestrial life will likely rely on the de-tection of biomarkers, highlighting the importance of preventing forward contamination not only with viable microorganisms, but also with biomolecules that could compromise the valid-ity of life-detection experiments [2-4]. The designation of DNA as a high-priority biomarker makes it necessary to evaluate its persistence in extraterrestrial environments, and the effects of exposure on its biological activity. To accomplish this, we deposited naked DNA, cells and spores of Bacillus subtilis 168 or B. pumilus SAFR-032, or cells of Acinetobacter radioresistens 50v1 onto spacecraft-qualified aluminum coupons. Samples were exposed to a simulated Mars surface environment as described in detail previously [4, 5] for various periods of time, and DNA damage was assessed by a number of measurements. Double-and single-strand breaks were measured by neutral and alkaline agarose gel electrophoresis, and DNA bipyrimidine pho-toproducts were measured by HPLC-mass spectrometry, as described previously [6, 7]. Loss of functionality of DNA to serve as a template for replication by DNA polymerase was measured using a quantitative polymerase chain reaction (qPCR) assay [8]. In all cases, DNA damage was directly correlated with time of exposure to simulated martian solar radiation (UV, visible, and infrared wavelengths). Exposure of samples to Mars surface conditions, but shielded from solar radiation, did not result in appreciable damage over the time periods tested, relative to controls. DNA contained within cells or spores was much less susceptible to damage than was naked DNA. Using the qPCR assay, we found that inactivation of naked DNA or DNA extracted from exposed spores of B. subtilis followed a multiphasic dose-response, and that a fraction of DNA molecules retained functionality after

  15. Material Surface Damage under High Pulse Loads Typical for ELM Bursts and Disruptions in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Landman, I.S.; Pestchanyi, S.E.; Bazylev, B.N [Forschungszentrum Karlsruhe (Germany). Inst. for Pulsed Power and Microwave Technology; Safronov, V.M. [Troitsk Inst. for Innovation and Fusion Research (TRINITI) (Russian Federation); Garkusha, I.E. [Kharkov Inst. of Physics and Technology (KIPT) (Ukraine). Inst. of Plasma Physics

    2004-08-01

    The divertor armour material for the tokamak ITER will probably be carbon manufactured as fibre composites (CFC) and tungsten as either brush-like structures or thin plates. Disruptive pulse loads where the heat deposition Q may reach 10{sup 2} MJ/m{sup 2} on a time scale {tau} of 3 ms, or operation in the ELMy H-mode at repetitive loads with Q {approx} 3MJ/m{sup 2} and {tau}{approx}0.3 ms; deteriorate armour performance. This work surveys recent numerical and experimental investigations of erosion mechanisms at these off-normal regimes carried out at FZK, TRINITI, and IPP-Kharkov. The modelling uses the anisotropic thermomechanics code PEGASUS-3D for the simulation of CFC brittle destruction, the surface melt motion code MEMOS-1.5D for tungsten targets, and the radiation-magnetohydrodynamics code FOREV-2D for calculating the plasma impact and simulating the heat loads for the ITER regime. Experiments aimed at validating these codes are being carried out at the plasma gun facilities MK-200UG, QSPA-T, and QSPA-Kh50 which produce powerful streams of hydrogen plasma with Q=10-30MJ/m{sup 2} and {tau} = 0.03-0.5 ms. Essential results are, for CFC targets, the experiments at high heat loads and the development of a local overheating model incorporated in PEGASUS-3D, and for the tungsten targets the analysis of evaporation- and melt motion erosion on the base of MEMOS-1.5D calculations for repetitive ELMs.

  16. Material Surface Damage under High Pulse Loads Typical for ELM Bursts and Disruptions in ITER

    Science.gov (United States)

    Landman, I. S.; Pestchanyi, S. E.; Safronov, V. M.; Bazylev, B. N.; Garkusha, I. E.

    The divertor armour material for the tokamak ITER will probably be carbon manufactured as fibre composites (CFC) and tungsten as either brush-like structures or thin plates. Disruptive pulse loads where the heat deposition Q may reach 102 MJ/m 2 on a time scale Ïä of 3 ms, or operation in the ELMy H-mode at repetitive loads with Q âe 1/4 3 MJ/m2 and Ïä âe 1/4 0.3 ms, deteriorate armour performance. This work surveys recent numerical and experimental investigations of erosion mechanisms at these off-normal regimes carried out at FZK, TRINITI, and IPP-Kharkov. The modelling uses the anisotropic thermomechanics code PEGASUS-3D for the simulation of CFC brittle destruction, the surface melt motion code MEMOS-1.5D for tungsten targets, and the radiation-magnetohydrodynamics code FOREV-2D for calculating the plasma impact and simulating the heat loads for the ITER regime. Experiments aimed at validating these codes are being carried out at the plasma gun facilities MK-200UG, QSPA-T, and QSPA-Kh50 which produce powerful streams of hydrogen plasma with Q = 10–30 MJ/m2 and Ïä = 0.03–0.5 ms. Essential results are, for CFC targets, the experiments at high heat loads and the development of a local overheating model incorporated in PEGASUS-3D, and for the tungsten targets the analysis of evaporation- and melt motion erosion on the base of MEMOS-1.5D calculations for repetitive ELMs.

  17. Damage of niobium surfaces caused by bombardment with 4He+ ions of different energies typical for T-20

    International Nuclear Information System (INIS)

    Guseva, M.I.; Gusev, V.; Martynenko, Yu.V.; Das, S.K.; Kaminsky, N.

    1979-01-01

    The surface damage of cold worked and annealed polycrystalline Nb irradiated at room temperature with He + ions sequentially at different energies over the range from 0.5 keV to 1.8 MeV has been investigated. The individual energy and the dose of the He + ion was chosen to match the theoretically calculated He + ion spectrum expected in the Tokamak T-20. In one set of irradiations, targets were irradiated at Kurchatov Institute starting with 0.5 keV 4 He + ions and extending up to 90 keV in eleven steps. Subsequently, the same area was irradiated at ANL starting at 150 keV and increased in eight steps up to 1.8 MeV. The irradiations were carried out for a total dose of 5.0 C/cm 2 . In another set of irradiations the sequence was reversed. Scanning electron microscopy results show formation of blisters and exfoliation. For the same dose the broad energy implant (due to sequential irradiation) appears to decrease the blister diameter and density as compared to irradiation with monoenergetic He + ions at a given energy (in the energy range considered). Some estimates of surface erosion yields due to blistering are given

  18. Study of Surface Wear and Damage Induced by Dry Sliding of Tempered AISI 4140 Steel against Hardened AISI 1055 Steel

    Directory of Open Access Journals (Sweden)

    A. Elhadi

    2016-12-01

    Full Text Available In industry, the sliding mechanical systems are subject to friction and wear phenomena. These phenomena can be the origin of a reduction of the efficiency of the mechanical system even to be responsible for its incapacity. Generally, the materials of the parts which are moving relative (tribological couple of these systems are low alloy steels and carbon steels, thanks to their good mechanical and tribological properties. The present work aimed to study, the surface wear and damage induced by dry sliding of hard carbon steel AISI 1055 (disc against tempered low alloy steel AISI 4140 (pin with different hardness and applied loads was investigated. The results revealed that the interaction between the applied load and pin hardness result in complex thermo-mechanical behaviour of the worn surfaces. When a lower hardness pin is used, the main wear mechanisms observed on the discs were abrasion, adhesion, and oxidation. When a higher hardness pin is used, the wear of the discs is governed by delamination, oxidation, and plastic deformation. In particular, third-body wear occurs at high applied load resulting in higher wear rate of high hardness pins compared to low hardness pins.

  19. Study of laser-induced damage on the exit surface of silica components in the nanosecond regime in a multiple wavelengths configuration

    International Nuclear Information System (INIS)

    Chambonneau, Maxime

    2014-01-01

    In this thesis, laser-induced damage phenomenon on the surface of fused silica components is investigated in the nanosecond regime. This phenomenon consists in an irreversible modification of the material. In the nanosecond regime, laser damage is tightly correlated to the presence of non-detectable precursor defects which are a consequence of the synthesis and the polishing of the components. In this thesis, we investigate laser damage in a multiple wavelengths configuration. In order to better understand this phenomenon in these conditions of irradiation, three studies are conducted. The first one focuses on damage initiation. The results obtained in the single wavelength configurations highlight a coupling in the multiple wavelengths one. A comparison between the experiments and a model developed during this thesis enables us to improve the knowledge of the fundamental processes involved during this damage phase. Then, we show that post mortem characterizations of damage morphology coupled to an accurate metrology allow us to understand both the nature and also the chronology of the physical mechanisms involved during damage formation. The proposed theoretical scenario is confirmed through various experiments. Finally, we study damage growth in both the single and the multiple wavelengths cases. Once again, this last configuration highlights a coupling between the wavelengths. We show the necessity to account for the spatial characteristics of the laser beams during a growth session. (author) [fr

  20. A new approach to assess the chemical composition of powder deposits damaging the stone surfaces of historical monuments.

    Science.gov (United States)

    Fermo, Paola; Turrion, Raquel Gonzalez; Rosa, Mario; Omegna, Alessandra

    2015-04-01

    The issue of conservation of the monumental heritage worldwide is mainly related to atmospheric pollution that causes the degradation of stone surfaces. The powder deposits present on the stone monuments reflect the composition of the aerosol particulate matter (PM) to which the surfaces are exposed, so the chemical characterization of the outermost damaged layers is necessary in order to adopt mitigation measurements to reduce PM emissions. In the present paper, a new analytical approach is proposed to investigate the chemical composition of powder deposits present on Angera stone, a dolomitic rock used in the Richini courtyard, a masterpiece of Lombard Baroque and placed in Milan. Inorganic and organic components present in these deposits have been analyzed by IC (ion chromatography) and a new approach mainly bases on thermal analyses, respectively. Gypsum is the main inorganic constituent indicating a composition similar to that of black crusts, hard black patina covering the degraded building surfaces. Ammonium nitrate present in the powder is able to react with the stone substrate to form magnesium nitrate which can migrate into the porous stone. The carbonaceous fraction powder deposits (i.e. OC = Organic Carbon and EC = Elemental Carbon) have been quantified by a new simple thermal approach based on carbon hydrogen nitrogen (CHN) analysis. The presence of high concentration of EC confirms that the powder deposits are evolving to black crust. Low values of water-soluble organic carbon (WSOC, determined by total organic carbon-TOC), with respect to what is normally found in PM, may indicate a migration process of organic substances into the stone with a worsening of the conservation conditions. The presence of heavy metals of anthropogenic origin and acting as catalysts in the black crust formation process has been highlighted by SEM-EDS (electron microscopy coupled with an energy dispersive spectrometer) as well.

  1. Damage of niobium surfaces caused by bombardment with 4He+ ions of different energies typical for T-20

    International Nuclear Information System (INIS)

    Guseva, M.I.; Gusev, V.; Martynenko, Yu.V.; Das, S.K.; Kaminsky, M.

    1979-01-01

    The aim of the present studies was to study surface damage due to blistering of both annealed and cold-worked niobium (a candidate first wall material for keV) irradiated sequentially with 4 He + ions with energies of 0.5 to 1800 keV for a total dose of 5.0 C/cm 2 . A typical surface of cold-worked Nb after irradiations with 4 He + ions with increasing energy from 0.5 to 90 keV is shown. The blister diameters range from 0.1 μm to 3 μm, and most of the blisters have exfoliated. The blisters fall into several size classes, the two most dominant ones having most probable blister diameters of approx. 0.27 μm and approx. 2.0 μm. The skin thickness of the larger blisters was measured to be approx. 0.23 μm. Also shown is the same area after irradiation with 150-1800-keV 4 He + irradiation for a dose of 0.66 C/cm 2 . A few additional blisters can be seen. A cold-worked Nb surface that was irradiated only with 150-1800-keV 4 He + ions is also shown. It is seen that prior irradiation with 0.5-90-keV 4 He + helped in significantly reducing blistering. For a total dose of 0.5 C/cm 2 , the erosion yield due to helium blistering of Nb ranges from (5.4 +- 2.0) x 10 -3 to (1.5 +- 0.7) x 10 -2 atoms/ion. For the cold-worked Nb target the results indicate clearly that the 4 He + implantations for the energy range from 0.5 to 90 keV help to reduce both the density and diameter of blisters formed by subsequent He-implantation for the energy ranging from 150 to 1800 keV. 2 figures

  2. Relationship between Deck Level, Body Surface Temperature and Carcass Damages in Italian Heavy Pigs after Short Journeys at Different Unloading Environmental Conditions.

    Science.gov (United States)

    Arduini, Agnese; Redaelli, Veronica; Luzi, Fabio; Dall'Olio, Stefania; Pace, Vincenzo; Nanni Costa, Leonardo

    2017-02-10

    In order to evaluate the relationships between deck level, body surface temperature and carcass damages after a short journey (30 min), 10 deliveries of Italian heavy pigs, including a total of 1400 animals from one farm, were examined. Within 5 min after the arrival at the abattoir, the vehicles were unloaded. Environmental temperature and relative humidity were recorded and a Temperature Humidity Index (THI) was calculated. After unloading, maximum temperatures of dorsal and ocular regions were measured by a thermal camera on groups of pigs from each of the unloaded decks. After dehairing, quarters and whole carcasses were evaluated subjectively by a trained operator for skin damage using a four-point scale. On the basis of THI at unloading, deliveries were grouped into three classes. Data of body surface temperature and skin damage score were analysed in a model including THI class, deck level and their interaction. Regardless of pig location in the truck, the maximum temperature of the dorsal and ocular regions increased with increasing THI class. Within each THI class, the highest and lowest body surface temperatures were found in pigs located on the middle and upper decks, respectively. Only THI class was found to affect the skin damage score ( p trucks, even at relatively low temperature and THI, in order to improve welfare and reduce loss of carcass value.

  3. Kinetics of Accumulation of Damage in Surface Layers of Lithium-Containing Aluminum Alloys in Fatigue Tests with Rigid Loading Cycle and Corrosive Effect of Environment

    Science.gov (United States)

    Morozova, L. V.; Zhegina, I. P.; Grigorenko, V. B.; Fomina, M. A.

    2017-07-01

    High-resolution methods of metal physics research including electron, laser and optical microscopy are used to study the kinetics of the accumulation of slip lines and bands and the corrosion damage in the plastic zone of specimens of aluminum-lithium alloys 1441 and B-1469 in rigid-cycle fatigue tests under the joint action of applied stresses and corrosive environment. The strain parameters (the density of slip bands, the sizes of plastic zones near fracture, the surface roughness in singled-out zones) and the damage parameters (the sizes of pits and the pitting area) are evaluated.

  4. Study of surface damage on cell envelope assessed by AFM and flow cytometry of Lactobacillus plantarum exposed to ethanol and dehydration.

    Science.gov (United States)

    Bravo-Ferrada, B M; Gonçalves, S; Semorile, L; Santos, N C; Tymczyszyn, E E; Hollmann, A

    2015-06-01

    In this work, we evaluated freeze-drying damage at the surface level of oenological strain Lactobacillus plantarum UNQLp155, as well as its ability to grow in a synthetic wine with and without pre-acclimation. Damage on cell surface was studied by flow cytometry, zeta potential and atomic force microscopy, and cell survival was analysed by plate count. Results showed that beside cells acclimated at lower ethanol concentration (6% v/v) became more susceptible to drying than nonacclimated ones, after rehydration they maintain their increased ability to grow in a synthetic wine. Acclimation at a higher ethanol concentration (10% v/v) produces several damages on the cell surface losing its ability to grow in a synthetic wine. In this work, we showed for the first time that sublethal alterations on bacterial surface induced by a pre-acclimation with a low ethanol concentration (6%), upon a freeze-drying process, result in a better bacterial adaptation to the stress conditions of wine-like medium, as well as to the preservation process. Understanding the adaptation to ethanol of oenological strains and their effects on the preservation process has a strong impact on winemaking process and allows to define the most appropriate conditions to obtain malolactic starters cultures. © 2015 The Society for Applied Microbiology.

  5. Combined effect of bulk and surface damage on strip insulation properties of proton irradiated n$^{+}$-p silicon strip sensors

    CERN Document Server

    Dalal, R; Ranjan, K; Moll, M; Elliott-Peisert, A

    2014-01-01

    Silicon sensors in next generation hadron colliders willface a tremendously harsh radiation environment. Requirement tostudy rarest reaction channels with statistical constraints hasresulted in a huge increment in radiation flux, resulting in bothsurface damage and bulk damage. For sensors which are used in acharged hadron environment, both of these degrading processes takeplace simultaneously. Recently it has been observed in protonirradiated n$^{+}$-p Si strip sensors that n$^{+}$ strips had a goodinter-strip insulation with low values of p-spray and p-stop dopingdensities which is contrary to the expected behaviour from thecurrent understanding of radiation damage. In this work a simulationmodel has been devised incorporating radiation damage to understandand provide a possible explanation to the observed behaviour ofirradiated sensors.

  6. Time-resolved imaging of filamentary damage on the exit surface of fused silica induced by 1064 nm nanosecond laser pulse

    International Nuclear Information System (INIS)

    Chao, Shen; Xiang’ai, Cheng; Tian, Jiang; Zhiwu, Zhu; Yifan, Dai

    2015-01-01

    Laser-induced damage on the exit surface of fused silica with a filament was observed. The filament has a central hollow core surrounded by molten materials and no obvious cracks could be observed. The critical intensity for the transition from pure surface damage (SD) to filamentary damage (FD) was measured. Time-resolved shadowgraphic microscopy with nanosecond time resolution was employed to compare the propagation of shock wave and material response in the SD and FD process. The main different features during the material response process include: (i) thermoelastic shock waves launched in FD were multiple and a column envelope was observed in the lateral direction; (ii) more energy is deposited in the bulk for FD resulting to a lower speed of shock wave in air; (iii) the overall time for establishing the main character of the damage site for FD was shorter because of the absence of crack expansion. Self-focusing and temperature-activated optical absorption enhancement of the bulk material are discussed to explain the morphology difference between SD and FD and the evolution of filament length under different incident intensities. (paper)

  7. Activation of protein kinase A and clustering of cell surface receptors by N-methyl-N'-nitro-N-nitrosoguanidine are independent of genomic DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zheng; Wang Guliang; Yang Jun; Guo Lei; Yu Yingnian

    2003-07-25

    Alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) induces cellular stress leading to chromosomal aberrations, mutations and cell death. Previous reports from our laboratory have shown that low concentration of MNNG induces untargeted mutation (UTM), which occurs on intact DNA in mammalian cells through changes in gene expression profile. It also causes the activation of cAMP-protein kinase A (PKA) and up-regulation of POL-{beta}, which is demonstrated to play a role in DNA repair system. In order to find out the possible initial signal involved in UTM, we try to investigate whether the activation of PKA-CREB signal pathway is closely related to DNA damage. Our data shows that the treatment of low concentration MNNG (0.2 {mu}M) activates PKA-CREB pathway in a comparable level both in a nuclear and enucleated cell system. And similar to the cell response caused by UV, the clustering of cell surface receptors of epidermal growth factor (EGF) and tumor necrosis factor {alpha} (TNF{alpha}) was also observed in cells exposed to MNNG. It was further demonstrated that the clustering of the surface receptors is independent of the genomic DNA damage, as this phenomenon was also observed in enucleated cells. These observations indicate that the initiation of signal cascades induced by low concentration of MNNG might be associated with its interaction with cell surface receptors and/or direct activation of related signal proteins but not its DNA damaging property.

  8. Relationship between Deck Level, Body Surface Temperature and Carcass Damages in Italian Heavy Pigs after Short Journeys at Different Unloading Environmental Conditions

    Directory of Open Access Journals (Sweden)

    Agnese Arduini

    2017-02-01

    Full Text Available In order to evaluate the relationships between deck level, body surface temperature and carcass damages after a short journey (30 min, 10 deliveries of Italian heavy pigs, including a total of 1400 animals from one farm, were examined. Within 5 min after the arrival at the abattoir, the vehicles were unloaded. Environmental temperature and relative humidity were recorded and a Temperature Humidity Index (THI was calculated. After unloading, maximum temperatures of dorsal and ocular regions were measured by a thermal camera on groups of pigs from each of the unloaded decks. After dehairing, quarters and whole carcasses were evaluated subjectively by a trained operator for skin damage using a four-point scale. On the basis of THI at unloading, deliveries were grouped into three classes. Data of body surface temperature and skin damage score were analysed in a model including THI class, deck level and their interaction. Regardless of pig location in the truck, the maximum temperature of the dorsal and ocular regions increased with increasing THI class. Within each THI class, the highest and lowest body surface temperatures were found in pigs located on the middle and upper decks, respectively. Only THI class was found to affect the skin damage score (p < 0.05, which increased on quarters and whole carcasses with increasing THI class. The results of this study on short-distance transport of Italian heavy pigs highlighted the need to control and ameliorate the environmental conditions in the trucks, even at relatively low temperature and THI, in order to improve welfare and reduce loss of carcass value.

  9. Fiscal 1991 achievement report on next-generation industrial structure technology. Research and development of advanced materials for extreme environments (Development of methane fueled aeroengine); 1991 nendo chotaikankyosei senshin zairyo no kenkyu kaihatsu seika hokokusho. Methane nenryo kokukiyo engine no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1992-03-01

    Research and development was carried out for intermetallic compounds and fiber reinforced intermetallic compound composite materials for use as advanced materials. Activities were conducted in the four fields of (1) high specific strength intermetallic compounds, (2) high melting point intermetallic compounds, (3) fiber reinforced intermetallic compound composite materials, and (4) a comprehensive survey and research. In Field (1), ternary phase diagrams (Mo, Nb) were prepared for Ti-Al-X (X=metal) systems, and studies were made of alloy designs for Ti-Al based high specific strength intermetallic compounds. In Field (2), binary phase diagrams were prepared for Nb-Al systems, and the effect of phase and structure on their basic properties were investigated. A powder manufacturing tester was designed and built, and basic powder manufacturing tests were conducted. In Field (3), studies were made of heat treatment and surface coating technologies, and a silicon carbide based fiber was developed, excellent in oxidation resistance. In Field (4), technical trends were surveyed, and studies were made as to basic technical tasks to discharge for the development of materials for aeroengines. (NEDO)

  10. Correlation of damage threshold and surface geometry of nodular defects in HR coatings as determined by in-situ atomic force microscopy

    International Nuclear Information System (INIS)

    Staggs, M.C.; Kozlowski, M.R.; Siekhaus, W.J.; Balooch, M.

    1992-10-01

    Atomic force microscopy (AFM) was used to determine in-situ the correlation between the surface dimensions of defects in dielectric multilayer optical coatings and their susceptibility to damage by pulsed laser illumination. The primary surface defects studied were μm-scale domes associated with the classic nodule defect. The optical film studied was a highly reflective dielectric multilayer consisting of pairs of alternating HfO 2 and SiO 2 layers of quarter wave thickness at 1.06 μm. Nodule defect height and width dimensions were measured prior to laser illumination on two different samples. Correlation between these dimensions supported a simple model for the defect geometry. Defects with high nodule heights (> 0.6 μm) were found to be most susceptible to laser damage over a range of fluences between 0-35 J/cm 2 (1.06 μm, 10 ns, and 1/e 2 diam. of 1.3 mm). Crater defects, formed by nodules ejected from the coating prior to illumination, were also studied. None of the crater defects damaged when illuminated over the same range of fluences that the nodule defects were subjected to

  11. Diclofenac protects cultured human corneal epithelial cells against hyperosmolarity and ameliorates corneal surface damage in a rat model of dry eye.

    Science.gov (United States)

    Sawazaki, Ryoichi; Ishihara, Tomoaki; Usui, Shinya; Hayashi, Erika; Tahara, Kayoko; Hoshino, Tatsuya; Higuchi, Akihiro; Nakamura, Shigeru; Tsubota, Kazuo; Mizushima, Tohru

    2014-04-21

    Dry eye syndrome (DES) is characterized by an increase in tear osmolarity and induction of the expression and nuclear localization of an osmoprotective transcription factor (nuclear factor of activated T-cells 5 [NFAT5]) that plays an important role in providing protection against hyperosmotic tears. In this study, we screened medicines already in clinical use with a view of finding compounds that protect cultured human corneal epithelial cells against hyperosmolarity-induced cell damage. Viable cell number was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method and cellular NFAT5 level was measured by immunoblotting. The rat model for DES was developed by removal of the lacrimal glands, with an assessment of corneal surface damage based on levels of fluorescein staining and epithelial apoptosis. Some nonsteroidal anti-inflammatory drugs (NSAIDs), including diclofenac sodium (diclofenac), were identified during the screening procedure. These NSAIDs were able to suppress hyperosmolarity-induced apoptosis and cell growth arrest. In contrast, other NSAIDs, including bromfenac sodium (bromfenac), did not exert such a protective action. Treatment of cells with diclofenac, but not bromfenac, stimulated both the nuclear localization and expression of NFAT5 under hyperosmotic conditions. In the rat model for DES, topical administration of diclofenac (but not bromfenac) to eyes reduced corneal surface damage without affecting the volume of tear fluid. Diclofenac appears to protect cells against hyperosmolarity-induced cell damage and NFAT5 would play an important role in this protective action. The findings reported here may also indicate that the topical administration of diclofenac to eyes may be therapeutically beneficial for DES patients.

  12. Surface damage versus defect microstructures in He and H ion co-implanted Si{sub 3}N{sub 4}/Si

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, F. [School of Science, Tianjin University, Tianjin 300072 (China); Liu, C.L., E-mail: liuchanglong@tju.edu.cn [School of Science, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Institute of Advanced Materials Physics Faculty of Science, Tianjin 300072 (China); Gao, Y.J.; Wang, Z.; Wang, J. [School of Science, Tianjin University, Tianjin 300072 (China)

    2012-09-01

    Cz n-type Si (1 0 0) wafers with a top Si{sub 3}N{sub 4} layer of about 170 nm in thickness were sequentially implanted with 40 keV He ions at a fluence of 5 Multiplication-Sign 10{sup 16}/cm{sup 2} and 35 keV H ions at fluences of 1 Multiplication-Sign 10{sup 15}, 5 Multiplication-Sign 10{sup 15} and 1 Multiplication-Sign 10{sup 16}/cm{sup 2}, respectively. Creation and evolution of surface damage as well as micro-defects have been studied. Our results clearly show that production of surface damage depends strongly on both the H implant fluence and annealing temperature. Only blistering or localized exfoliation of the top Si{sub 3}N{sub 4} layer has been observed for post H implantation at fluences of 1 Multiplication-Sign 10{sup 15} and 5 Multiplication-Sign 10{sup 15}/cm{sup 2} upon 800 Degree-Sign C annealing. However, serious surface exfoliation has been found for the 1 Multiplication-Sign 10{sup 16}/cm{sup 2} H co-implanted samples after annealing at 450 Degree-Sign C and above. The exfoliation occurs at a depth of about 360 nm from the surface, which is obviously larger than the He or H ion range. Moreover, the exfoliated craters show clear two-step structures. Cross-sectional transmission electron microscopy (XTEM) observations reveal formation of micro-cracks in Si bulk and along the original interface, which is mainly responsible for the observed surface phenomena. The formation mechanism of micro-cracks has been discussed in combination of He and H implant-induced defects, impurities as well as their interactions upon annealing.

  13. DNA damage and oxidative stress in human liver cell L-02 caused by surface water extracts during drinking water treatment in a waterworks in China.

    Science.gov (United States)

    Xie, Shao-Hua; Liu, Ai-Lin; Chen, Yan-Yan; Zhang, Li; Zhang, Hui-Juan; Jin, Bang-Xiong; Lu, Wen-Hong; Li, Xiao-Yan; Lu, Wen-Qing

    2010-04-01

    Because of the daily and life-long exposure to disinfection by-products formed during drinking water treatment, potential adverse human health risk of drinking water disinfection is of great concern. Toxicological studies have shown that drinking water treatment increases the genotoxicity of surface water. Drinking water treatment is comprised of different potabilization steps, which greatly influence the levels of genotoxic products in the surface water and thus may alter the toxicity and genotoxicity of surface water. The aim of the present study was to understand the influence of specific steps on toxicity and genotoxicity during the treatment of surface water in a water treatment plant using liquid chlorine as the disinfectant in China. An integrated approach of the comet and oxidative stress assays was used in the study, and the results showed that both the prechlorination and postchlorination steps increased DNA damage and oxidative stress caused by water extracts in human derived L-02 cells while the tube settling and filtration steps had the opposite effect. This research also highlighted the usefulness of an integrated approach of the comet and oxidative stress assays in evaluating the genotoxicity of surface water during drinking water treatment. Copyright 2009 Wiley-Liss, Inc.

  14. Impact load-induced micro-structural damage and micro-structure associated mechanical response of concrete made with different surface roughness and porosity aggregates

    International Nuclear Information System (INIS)

    Erdem, Savaş; Dawson, Andrew Robert; Thom, Nicholas Howard

    2012-01-01

    The relationship between the nature of micro damage under impact loading and changes in mechanical behavior associated with different microstructures is studied for concretes made with two different coarse aggregates having significant differences mainly in roughness and porosity — sintered fly ash and uncrushed gravel. A range of techniques including X-ray diffraction, digital image analysis, mercury porosimetry, X-ray computed tomography, laser surface profilometry and scanning electron microscopy were used to characterize the aggregates and micro-structures. The concrete prepared with lightweight aggregates was stronger in compression than the gravel aggregate concrete due to enhanced hydration as a result of internal curing. In the lightweight concrete, it was deduced that an inhomogeneous micro-structure led to strain incompatibilities and consequent localized stress concentrations in the mix, leading to accelerated failure. The pore structure, compressibility, and surface texture of the aggregates are of paramount importance for the micro-cracking growth.

  15. Enhanced Etching, Surface Damage Recovery, and Submicron Patterning of Hybrid Perovskites using a Chemically Gas-Assisted Focused-Ion Beam for Subwavelength Grating Photonic Applications

    KAUST Repository

    Alias, Mohd Sharizal

    2015-12-22

    The high optical gain and absorption of organic–inorganic hybrid perovskites have attracted attention for photonic device applications. However, owing to the sensitivity of organic moieties to solvents and temperature, device processing is challenging, particularly for patterning. Here, we report the direct patterning of perovskites using chemically gas-assisted focused-ion beam (GAFIB) etching with XeF2 and I2 precursors. We demonstrate etching enhancement in addition to controllability and marginal surface damage compared to focused-ion beam (FIB) etching without precursors. Utilizing the GAFIB etching, we fabricated a uniform and periodic submicron perovskite subwavelength grating (SWG) absorber with broadband absorption and nanoscale precision. Our results demonstrate the use of FIB as a submicron patterning tool and a means of providing surface treatment (after FIB patterning to minimize optical loss) for perovskite photonic nanostructures. The SWG absorber can be patterned on perovskite solar cells to enhance the device efficiency through increasing light trapping and absorption.

  16. Study on the role of laser surface irradiation on damage and decohesion of Al/epoxy joints

    KAUST Repository

    Alfano, Marco; Lubineau, Gilles; Furgiuele, Franco M.; Paulino, Glá ucio Hermogenes

    2012-01-01

    In this work we investigate the effect of laser irradiation on the bond toughness of aluminum/epoxy bonded joints. The evolution of substrate surface morphology and wettability, for various sets of laser process parameters (i.e. laser power, line spacing, scan speed), was investigated by means of Scanning Electron Microscopy (SEM) and contact angle measurements. A proper combination of power, line spacing and scan speed was then selected and adhesive bonded Al/epoxy T-peel joints were prepared and tested. For comparison, similar samples were produced using substrates with classical grit blasting surface treatment. Finally, post-failure SEM analyses of fracture surfaces were performed, and in order to typify the increase in bond toughness of the joints, finite element simulations were carried out using a potential based cohesive zone model of fracture. © 2012 Elsevier Ltd.

  17. Study on the role of laser surface irradiation on damage and decohesion of Al/epoxy joints

    KAUST Repository

    Alfano, Marco

    2012-12-01

    In this work we investigate the effect of laser irradiation on the bond toughness of aluminum/epoxy bonded joints. The evolution of substrate surface morphology and wettability, for various sets of laser process parameters (i.e. laser power, line spacing, scan speed), was investigated by means of Scanning Electron Microscopy (SEM) and contact angle measurements. A proper combination of power, line spacing and scan speed was then selected and adhesive bonded Al/epoxy T-peel joints were prepared and tested. For comparison, similar samples were produced using substrates with classical grit blasting surface treatment. Finally, post-failure SEM analyses of fracture surfaces were performed, and in order to typify the increase in bond toughness of the joints, finite element simulations were carried out using a potential based cohesive zone model of fracture. © 2012 Elsevier Ltd.

  18. Protective or damage promoting effect of calcium carbonate layers on the surface of cement based materials in aqueous environments

    International Nuclear Information System (INIS)

    Schwotzer, M.; Scherer, T.; Gerdes, A.

    2010-01-01

    Cement based materials permanently exposed to aggressive aqueous environments are subject to chemical changes affecting their durability. However, this holds also for tap water that is considered to be not aggressive to cementitious materials, although in that case a formation of covering layers of CaCO 3 on the alkaline surfaces is commonly supposed to provide protection against reactive transport processes. Thus, investigations of the structural and chemical properties of the material/water interface were carried out in laboratory experiments and case studies to elucidate the consequences of surface reactions for the durability of cement based materials exposed to tap water. Focused Ion Beam investigations revealed that a protective effect of a CaCO 3 covering layer depends on its structural properties, which are in turn affected by the hydro-chemical conditions during crystallization. Surface precipitation of CaCO 3 can trigger further chemical degradation, if the required calcium is supplied by the pore solution of the material.

  19. A bioluminescence ATP assay for estimating surface hydrophobicity and membrane damage of Escherichia coli cells treated with pulsed electric fields

    Science.gov (United States)

    Pulse Electric Field (PEF) treatments, a non-thermal process have been reported to injure and inactivate bacteria in liquid foods. However, the effect of this treatment on bacterial cell surface charge and hydrophobicity has not been investigated. Apple juice (AJ, pH 3.8) purchased from a wholesale ...

  20. A molecular dynamics computer simulation of the time dependence of surface damage production in ion irradiated metal targets

    International Nuclear Information System (INIS)

    Webb, R.P.; Harrison, D.E.

    1984-01-01

    Molecular dynamics computer simulations have been used to study the development of ion-induced cascades in the surface region of an initially perfect single crystal metal target. A 16 mm movie has been produced to show the temporal progress of individual cascades. The cascades can then be seen to be formed from a few high energy primary knock-on initiated replacement collision sequences which overlap to form the more usual interpretation of a mature collision cascade. However, it is before the collision cascade has matured, and while the replacement sequences are spreading, that the majority of atoms (> 80%) are ejected. These qualitative observations are also upheld more quantatively in a global average, over many cascades, of the ejection time of each atom. This gives rise to the appearance of a statistical ejection front which propagates radially outwards, from the impact point on the crystal surface, with a well defined velocity. (author)

  1. Applications of high order harmonic radiation to UVX-solids interaction: high excitation density in electronic relaxation dynamics and surface damaging

    International Nuclear Information System (INIS)

    De Grazia, M.

    2007-12-01

    The new sources of radiation in the extreme-UV (X-UV: 10-100 nm), which deliver spatially coherent, ultra-short and intense pulses, allow studying high flux processes and ultra-fast dynamics in various domains. The thesis work presents two applications of the high-order laser harmonics (HH) to solid state physics. In Part I, we describe the optimization of the harmonic for studies of X-UV/solids interaction. In Part II, we investigate effects of high excitation density in the dynamics of electron relaxation in dielectric scintillator crystals - tungstates and fluorides, using time-resolved luminescence spectroscopy. Quenching of luminescence at short time gives evidence of the competition between radiative and non-radiative recombination of self-trapped excitons (STE). The non-radiative channel is identified to mutual interaction of STE at high excitation density. In Part III, we study the X-UV induced damage mechanism in various materials, either conductor (amorphous carbon) or insulators (organic polymers, e.g., PMMA). In PMMA-Plexiglas, in the desorption regime (0.2 mJ/cm 2 , i.e., below damage threshold), the surface modifications reflect X-UV induced photochemical processes that are tentatively identified, as a function of dose: at low dose, polymer chain scission followed by the blow-up of the volatile, low-molecular fragments leads to crater formation; at high dose, cross-linking in the near-surface layer of remaining material leads to surface hardening. These promising results have great perspectives considering the performances already attained and planned in the next future in the development of the harmonic sources. (author)

  2. Radiation damages of material surfaces by plasma emission in thermonuclear devices. Methods of study of surface phenomena and simulation effect of thermonuclear plasma

    International Nuclear Information System (INIS)

    Rybalko, V.F.

    1978-01-01

    Phenomena that can introduce a controlling contribution into the erosion of the first wall surface in thermonuclear reactor are reviewed. Considered are the main characteristics of the physical disintegration: dependence of the disintegration coefficient upon the energy and the incidence angle of the bombarding particles, upon the atomic number of the material of the target and the type of bombarding particles. Stressed is the lack of reliable data on the disintegration of materials by light ions, which are of a maximum interest in relation to the controlled thermonuclear synthesis. The chemical disintegration and some regularities of it for the carbon-hydrogen and carbon-oxygen systems are discussed briefly. Listed are the main properties of blistering and its contribution to the erosion of crystalline surfaces

  3. Molecular mechanism of ocular surface damage: application to an in vitro dry eye model on human corneal epithelium.

    Science.gov (United States)

    Meloni, Marisa; De Servi, Barbara; Marasco, Daniela; Del Prete, Salvatore

    2011-01-12

    The present study was concerned with the development of a new experimental model of dry eye using human reconstructed in vitro corneal epithelium (HCE). The model is based on the use of adapted culture conditions that induce relevant modifications at the cellular and molecular level thus mimicking dry eye. The HCE model was maintained in a controlled environmental setting (relative humidity eye. The evolution of the dry eye condition was assessed by histology, immunohistochemistry staining, scanning electron microscopy, and gene expression by using TaqMan gene assay technology (mucin-4 [MUC4], matrix metallopeptidase-9 [MMP9], tumor necrosis factor-α [TNF-α], and defensin β-2 [DEFB2). The effects of different commercially available tear substitutes on the induced dry eye condition were tested. This in vitro dry eye HCE model, that was well established within 24 h, has the characteristic features of a dry eye epithelium and could be satisfactorily used for preliminary assessment of the protective activity of some artificial tears. The transcriptional study of selected biomarkers showed an increase in MUC4, MMP9, TNF-α, and hBD-2 (DEFB2) gene expression. By using a dynamic approach, we were able to define a biomarker gene signature of dry eye-induced effects that could be predictive of corneal damage in vivo and to discriminate the efficacy among different commercial artificial tears.

  4. Surface damage mitigation of TC4 alloy via micro arc oxidation for oil and gas exploitation application: Characterizations of microstructure and evaluations on surface performance

    Science.gov (United States)

    Xie, Ruizhen; Lin, Naiming; Zhou, Peng; Zou, Jiaojuan; Han, Pengju; Wang, Zhihua; Tang, Bin

    2018-04-01

    Because of its excellent corrosion resistance, high specific strength and high tensile strength, TC4 titanium alloys used as petroleum tubes have received wide interest from material engineers after many technical investigations and estimations. However, because of its low surface hardness values, high coefficient of friction and poor wear resistance, the TC4 alloy is seldom adopted in tribological-related engineering components. In this work, micro-arc oxidation (MAO) coatings were fabricated on TC4 alloys in NaAlO2 and (NaPO3)6 electrolytes with and without ultrasonic assistance. The microstructural characterizations of the produced MAO coatings were investigated. Comparative estimations of electrochemical corrosion in CO2-saturated simulated oilfield brine and tribological behaviours on MAO coatings and TC4 alloys were conducted. The results showed that the introduction of ultrasound increased the thickness of the MAO coatings. The thickness increased by 34% and 15% in the NaAlO2 and (NaPO3)6 electrolytes, respectively. There was no significant discrepancy in phase constitutions when the MAO processes were conducted with and without ultrasonic assistance. Both MAO coatings obtained with and without ultrasonic assistance were found to improve the corrosion and wear resistance of the TC4 alloy. MAO treatments made it possible to ensure the working surface of a TC4 alloy with an enhanced surface performance for oil and gas exploitation applications.

  5. Unusual surface and edge morphologies, sp2 to sp3 hybridized transformation and electronic damage after Ar+ ion irradiation of few-layer graphene surfaces.

    Science.gov (United States)

    Al-Harthi, Salim Hamood; Elzain, Mohammed; Al-Barwani, Muataz; Kora'a, Amal; Hysen, Thomas; Myint, Myo Tay Zar; Anantharaman, Maliemadom Ramaswamy

    2012-08-19

    Roughness and defects induced on few-layer graphene (FLG) irradiated by Ar+ ions at different energies were investigated using X-ray photoemission spectroscopy (XPS) and atomic force microscopy techniques. The results provide direct experimental evidence of ripple formation, sp2 to sp3 hybridized carbon transformation, electronic damage, Ar+ implantation, unusual defects and edge reconstructions in FLG, which depend on the irradiation energy. In addition, shadowing effects similar to those found in oblique-angle growth of thin films were seen. Reliable quantification of the transition from the sp2-bonding to sp3-hybridized state as a result of Ar+ ion irradiation is achieved from the deconvolution of the XPS C (1s) peak. Although the ion irradiation effect is demonstrated through the shape of the derivative of the Auger transition C KVV spectra, we show that the D parameter values obtained from these spectra which are normally used in the literature fail to account for the sp2 to sp3 hybridization transition. In contrast to what is known, it is revealed that using ion irradiation at large FLG sample tilt angles can lead to edge reconstructions. Furthermore, FLG irradiation by low energy of 0.25 keV can be a plausible way of peeling graphene layers without the need of Joule heating reported previously.

  6. Measurement of Surface Damage through Boundary Detection: An Approach to Assess Durability of Cementitious Composites under Tannery Wastewater

    Directory of Open Access Journals (Sweden)

    Tanvir Manzur

    2016-01-01

    Full Text Available Concrete structures are often subjected to aggressive aqueous environments which consist of several chemical agents that can react with concrete to produce adverse effects. A Central Effluent Treatment Plant consisting of reinforced concrete structures which is being constructed at Savar, Bangladesh, is an example of such a case. The purpose of this treatment facility is to reduce the environmental pollution created by tannery wastewater. However, tannery wastewater consists of several chemicals such as sulfates, chlorides, and ammonium, which, from the literature, are known to generate detrimental effects on concrete. Evaluation of durability of concrete structures in such environments is therefore imperative. This paper highlights a technique of boundary detection developed through image processing performed using MATLAB. Cement mortar cubes were submerged in simulated tannery wastewater and the images of the surface of cubes were taken at several time intervals. In addition, readings for compressive strength and weight were also taken on the same days. In this paper, an attempt is made to correlate the results from image processing with that of strength and weight loss. It was found, within the scope of this study, that the specimens which suffered greater strength and weight loss also underwent greater loss of surface area.

  7. Damage detection of engine bladed-disks using multivariate statistical analysis

    Science.gov (United States)

    Fang, X.; Tang, J.

    2006-03-01

    The timely detection of damage in aero-engine bladed-disks is an extremely important and challenging research topic. Bladed-disks have high modal density and, particularly, their vibration responses are subject to significant uncertainties due to manufacturing tolerance (blade-to-blade difference or mistuning), operating condition change and sensor noise. In this study, we present a new methodology for the on-line damage detection of engine bladed-disks using their vibratory responses during spin-up or spin-down operations which can be measured by blade-tip-timing sensing technique. We apply a principle component analysis (PCA)-based approach for data compression, feature extraction, and denoising. The non-model based damage detection is achieved by analyzing the change between response features of the healthy structure and of the damaged one. We facilitate such comparison by incorporating the Hotelling's statistic T2 analysis, which yields damage declaration with a given confidence level. The effectiveness of the method is demonstrated by case studies.

  8. Earthquake damage to underground facilities

    International Nuclear Information System (INIS)

    Pratt, H.R.; Hustrulid, W.A.; Stephenson, D.E.

    1978-11-01

    The potential seismic risk for an underground nuclear waste repository will be one of the considerations in evaluating its ultimate location. However, the risk to subsurface facilities cannot be judged by applying intensity ratings derived from the surface effects of an earthquake. A literature review and analysis were performed to document the damage and non-damage due to earthquakes to underground facilities. Damage from earthquakes to tunnels, s, and wells and damage (rock bursts) from mining operations were investigated. Damage from documented nuclear events was also included in the study where applicable. There are very few data on damage in the subsurface due to earthquakes. This fact itself attests to the lessened effect of earthquakes in the subsurface because mines exist in areas where strong earthquakes have done extensive surface damage. More damage is reported in shallow tunnels near the surface than in deep mines. In mines and tunnels, large displacements occur primarily along pre-existing faults and fractures or at the surface entrance to these facilities.Data indicate vertical structures such as wells and shafts are less susceptible to damage than surface facilities. More analysis is required before seismic criteria can be formulated for the siting of a nuclear waste repository

  9. Multi-method Near-surface Geophysical Surveys for Site Response and Earthquake Damage Assessments at School Sites in Washington, USA

    Science.gov (United States)

    Cakir, R.; Walsh, T. J.; Norman, D. K.

    2017-12-01

    We, Washington Geological Survey (WGS), have been performing multi-method near surface geophysical surveys to help assess potential earthquake damage at public schools in Washington. We have been conducting active and passive seismic surveys, and estimating Shear-wave velocity (Vs) profiles, then determining the NEHRP soil classifications based on Vs30m values at school sites in Washington. The survey methods we have used: 1D and 2D MASW and MAM, P- and S-wave refraction, horizontal-to-vertical spectral ratio (H/V), and 2ST-SPAC to measure Vs and Vp at shallow (0-70m) and greater depths at the sites. We have also run Ground Penetrating Radar (GPR) surveys at the sites to check possible horizontal subsurface variations along and between the seismic survey lines and the actual locations of the school buildings. The seismic survey results were then used to calculate Vs30m for determining the NEHRP soil classifications at school sites, thus soil amplification effects on the ground motions. Resulting shear-wave velocity profiles generated from these studies can also be used for site response and liquefaction potential studies, as well as for improvement efforts of the national Vs30m database, essential information for ShakeMap and ground motion modeling efforts in Washington and Pacific Northwest. To estimate casualties, nonstructural, and structural losses caused by the potential earthquakes in the region, we used these seismic site characterization results associated with structural engineering evaluations based on ASCE41 or FEMA 154 (Rapid Visual Screening) as inputs in FEMA Hazus-Advanced Engineering Building Module (AEBM) analysis. Compelling example surveys will be presented for the school sites in western and eastern Washington.

  10. Radiation-induced damage of membranes

    International Nuclear Information System (INIS)

    Yonei, Shuji

    1977-01-01

    An outline of membranous structure was stated, and radiation-induced damage of membranes were surveyed. By irradiation, permeability of membranes, especially passive transportation mechanism, was damaged, and glycoprotein in the surface layers of cells and the surface layer structures were changed. The intramembranous damage was induced by decrease of electrophoresis of nuclear mambranes and a quantitative change of cytochrome P450 of microsomal membranes of the liver, and peroxidation of membranous lipid and SH substitute damage of membranous protein were mentioned as the mechanism of membranous damage. Recovery of membranous damage depends on radiation dose and temperature, and membranous damage participates largely in proliferation death. (tsunoda, M.)

  11. LX-10 Explosive Damage Studies

    Science.gov (United States)

    2015-03-03

    opposite end of the vessel. The inside of the bomb is fitted with a stainless steel liner to protect the inner surface and to change the bomb...19  18. Size Fractions for Spherical LX-10 Samples Impact Damaged Between 312 and 416 ft/s...19  19. Spherical LX-10 Sample Impact Damaged at 416 ft/s ....................................... 20  20

  12. Radiation damage

    CERN Document Server

    Heijne, Erik H M; CERN. Geneva

    1998-01-01

    a) Radiation damage in organic materials. This series of lectures will give an overview of radiation effects on materials and components frequently used in accelerator engineering and experiments. Basic degradation phenomena will be presented for organic materials with comprehensive damage threshold doses for commonly used rubbers, thermoplastics, thermosets and composite materials. Some indications will be given for glass, scintillators and optical fibres. b) Radiation effects in semiconductor materials and devices. The major part of the time will be devoted to treat radiation effects in semiconductor sensors and the associated electronics, in particular displacement damage, interface and single event phenomena. Evaluation methods and practical aspects will be shown. Strategies will be developed for the survival of the materials under the expected environmental conditions of the LHC machine and detectors. I will describe profound revolution in our understanding of black holes and their relation to quantum me...

  13. Damage to the surface of the small intestinal villus: an objective scale of assessment of the effects of single and fractionated radiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Carr, K.E.; Watt, C. (Glasgow Univ. (UK). Dept. of Anatomy); Hamlet, R.; Nias, A.H.W. (Glasgow Inst. of Radiotherapeutics and Oncology (UK))

    1983-07-01

    Scanning electron microscopy has been used to compare damage to mouse small intestinal mucosa after irradiation with different doses of photons and neutrons. Various stages of the collapse of villous structure seen after radiation include the production of conical and rudimentary villi and a flattened mucosa. A scale is proposed to relate radiation to villous damage. Points from this scale are taken to produce comparative ratios for equivalent damage produced by different radiation conditions. RBE values are quoted for neutron, X and gamma radiation given as single or fractionated irradiation doses and as whole or partial body irradiation. The relationship between the stroma in intravillous pegs and that of the pericryptal compartment is explored.

  14. Damage to the surface of the small intestinal villus: an objective scale of assessment of the effects of single and fractionated radiation doses

    International Nuclear Information System (INIS)

    Carr, K.E.; Watt, C.

    1983-01-01

    Scanning electron microscopy has been used to compare damage to mouse small intestinal mucosa after irradiation with different doses of photons and neutrons. Various stages of the collapse of villous structure seen after radiation include the production of conical and rudimentary villi and a flattened mucosa. A scale is proposed to relate radiation to villous damage. Points from this scale are taken to produce comparative ratios for equivalent damage produced by different radiation conditions. RBE values are quoted for neutron, X and gamma radiation given as single or fractionated irradiation doses and as whole or partial body irradiation. The relationship between the stroma in intravillous pegs and that of the pericryptal compartment is explored. (author)

  15. Tort Damages

    NARCIS (Netherlands)

    L.T. Visscher (Louis)

    2008-01-01

    textabstractAbstract: In this Chapter, I provide an overview of Law and Economics literature regarding tort damages. Where necessary, attention is also spent to rules of tort liability. Both types of rules provide behavioral incentives to both injurers and victims, with respect to their level of

  16. Analysis of the ways to decrease residual stresses on heat exchanging tubes and steam generator collector surfaces for reducing the material corrosion damage

    International Nuclear Information System (INIS)

    Stepanov, G.V.; Kharchenko, V.V.; Shatco, A.A.; Dranchenko, V.V.; Titov, V.F.

    1994-01-01

    Computer simulations have been carried out to analyze the effect of heat exchanger tube pressing forming process into a steam generator collector, on its residual stresses and strains. The program takes into consideration kinetic process peculiarities, material non-linear rheological properties, separate deformation of tubes and collectors in the presence of a clearance and their contact interaction, damage and crack appearance. 4 figs

  17. Comparing the use of 4.6 um lasers versus 10.6 um lasers for mitigating damage site growth on fused silica surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S T; Matthews, M J; Elhadj, S; Cooke, D; Guss, G M; Draggoo, V G; Wegner, P J

    2010-10-21

    The advantage of using mid-infrared (IR) 4.6 {micro}m lasers, versus far-infrared 10.6 {micro}m lasers, for mitigating damage growth on fused silica is investigated. In contrast to fused silica's high absorption at 10.6 {micro}m, silica absorption at 4.6 {micro}m is two orders of magnitude less. The much reduced absorption at 4.6 {micro}m enables deep heat penetration into fused silica when it is heated using the mid-IR laser, which in turn leads to more effective mitigation of damage sites with deep cracks. The advantage of using mid-IR versus far-IR laser for damage growth mitigation under non-evaporative condition is quantified by defining a figure of merit (FOM) that relates the crack healing depth to laser power required. Based on our FOM, we show that for damage cracks up to at least 500 {micro}m in depth, mitigation using a 4.6 {micro}m mid-IR laser is more efficient than mitigation using a 10.6 {micro}m far-IR laser.

  18. Coal transportation road damage

    International Nuclear Information System (INIS)

    Burtraw, D.; Harrison, K.; Pawlowski, J.A.

    1994-01-01

    Heavy trucks are primarily responsible for pavement damage to the nation's highways. In this paper we evaluate the pavement damage caused by coal trucks. We analyze the chief source of pavement damage (vehicle weight per axle, not total vehicle weight) and the chief cost involved (the periodic overlay that is required when a road's surface becomes worn). This analysis is presented in two stages. In the first section we present a synopsis of current economic theory including simple versions of the formulas that can be: used to calculate costs of pavement wear. In the second section we apply this theory to a specific example proximate to the reference environment for the Fuel Cycle Study in New Mexico in order to provide a numerical measure of the magnitude of the costs

  19. Cavitation damage of ceramics

    International Nuclear Information System (INIS)

    Kovalenko, V.I.; Marinin, V.G.

    1988-01-01

    Consideration is given to results of investigation of ceramic material damage under the effect of cavitation field on their surface, formed in water under the face of exponential concentrator, connected with ultrasonic generator UZY-3-0.4. Amplitude of vibrations of concentrator face (30+-2)x10 -6 m, frequency-21 kHz. It was established that ceramics resistance to cavitation effect correlated with the product of critical of stress intensity factor and material hardness

  20. Effect of deep structure and surface layer (a) simulation study on the heavy damage belt of the 1995 Hyogoken Nanbu earthquake; Hado simulation wo mochiita `shinsai no obi` ni tsuite no kento

    Energy Technology Data Exchange (ETDEWEB)

    Feng, S; Ishikawa, K; Kaji, Y [Chuokaihatsu Corp., Tokyo (Japan)

    1996-05-01

    A simulation study was done to identify the causes for the so-called heavy damage belt observed as a result of the Hyogoken Nanbu Earthquake. This study determines distributions of the maximum amplitudes on the ground surfaces, and discusses the effects of deep structures and low-velocity surface layers, based on the simulation by the wave equation with the underground model of Higashinada-ku and its vicinity in the north-south direction, observed seismic records and artificial waves. The two-dimensional scalar wave equation is used for the analysis. The velocity structure model used for the simulation is established, based on the elastic wave seismic survey results. The focus function is drawn by expanding or contracting the time scale, using the seismic records at Kobe Port Island and artificial waves. The analysis results show that the damage belt coincides with the areas at which the focusing zone of the deep structure overlap the amplification zone in the low-velocity ground surfaces, where relative density is amplified 1.5 to 2 times. It is also observed that large peaks repeat 2 to 3 times on the time scale. 5 refs., 8 figs., 1 tab.

  1. Irradiation damage

    Energy Technology Data Exchange (ETDEWEB)

    Howe, L.M

    2000-07-01

    There is considerable interest in irradiation effects in intermetallic compounds from both the applied and fundamental aspects. Initially, this interest was associated mainly with nuclear reactor programs but it now extends to the fields of ion-beam modification of metals, behaviour of amorphous materials, ion-beam processing of electronic materials, and ion-beam simulations of various kinds. The field of irradiation damage in intermetallic compounds is rapidly expanding, and no attempt will be made in this chapter to cover all of the various aspects. Instead, attention will be focused on some specific areas and, hopefully, through these, some insight will be given into the physical processes involved, the present state of our knowledge, and the challenge of obtaining more comprehensive understanding in the future. The specific areas that will be covered are: point defects in intermetallic compounds; irradiation-enhanced ordering and irradiation-induced disordering of ordered alloys; irradiation-induced amorphization.

  2. Irradiation damage

    International Nuclear Information System (INIS)

    Howe, L.M.

    2000-01-01

    There is considerable interest in irradiation effects in intermetallic compounds from both the applied and fundamental aspects. Initially, this interest was associated mainly with nuclear reactor programs but it now extends to the fields of ion-beam modification of metals, behaviour of amorphous materials, ion-beam processing of electronic materials, and ion-beam simulations of various kinds. The field of irradiation damage in intermetallic compounds is rapidly expanding, and no attempt will be made in this chapter to cover all of the various aspects. Instead, attention will be focused on some specific areas and, hopefully, through these, some insight will be given into the physical processes involved, the present state of our knowledge, and the challenge of obtaining more comprehensive understanding in the future. The specific areas that will be covered are: point defects in intermetallic compounds; irradiation-enhanced ordering and irradiation-induced disordering of ordered alloys; irradiation-induced amorphization

  3. Mutagenicity and oxidative damage induced by an organic extract of the particulate emissions from a simulation of the deepwater horizon surface oil burns.

    Science.gov (United States)

    DeMarini, David M; Warren, Sarah H; Lavrich, Katelyn; Flen, Alexis; Aurell, Johanna; Mitchell, William; Greenwell, Dale; Preston, William; Schmid, Judith E; Linak, William P; Hays, Michael D; Samet, James M; Gullett, Brian K

    2017-04-01

    Emissions from oil fires associated with the "Deepwater Horizon" explosion and oil discharge that began on April 20, 2010 in the Gulf of Mexico were analyzed chemically to only a limited extent at the time but were shown to induce oxidative damage in vitro and in mice. To extend this work, we burned oil floating on sea water and performed extensive chemical analyses of the emissions (Gullett et al., Marine Pollut Bull, in press, ). Here, we examine the ability of a dichloromethane extract of the particulate material with an aerodynamic size ≤ 2.5 µm (PM 2.5 ) from those emissions to induce oxidative damage in human lung cells in vitro and mutagenicity in 6 strains of Salmonella. The extract had a percentage of extractable organic material (EOM) of 7.0% and increased expression of the heme oxygenase (HMOX1) gene in BEAS-2B cells after exposure for 4 hr at 20 µg of EOM/ml. However, the extract did not alter mitochondrial respiration rate as measured by extracellular flux analysis. The extract was most mutagenic in TA100 +S9, indicative of a role for polycyclic aromatic hydrocarbons (PAHs), reflective of the high concentrations of PAHs in the emissions (1 g/kg of oil consumed). The extract had a mutagenicity emission factor of 1.8 ± 0.1 × 10 5 revertants/megajoule thermal in TA98 +S9, which was greater than that of diesel exhaust and within an order of magnitude of open burning of wood and plastic. Thus, organics from PM 2.5 of burning oil can induce oxidative responses in human airway epithelial cells and are highly mutagenic. Environ. Mol. Mutagen. 58:162-171, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  4. Picosecond laser damage of fused silica at 355 nm

    International Nuclear Information System (INIS)

    Meng Xiangjie; Liu Hongjie; Wang Fang; Zhang Zhen; An Xinyou; Huang Jin; Jiang Xiaodong; Wu Weidong; Ren Weiyi

    2013-01-01

    This paper studies the initiated damage threshold, the damage morphology and the subsequent damage growth on fused silica's input-surface and exit-surface under picosecond laser irradiation at 355 nm. Defects induced fluorescence on surface of the optical component is observed. The results demonstrate a significant dependence of the initiated damage on pulse duration and surface defects, and that of the damage growth on self-focusing, sub-surface defects. The damage-threshold is 3.98 J/cm 2 of input surface and 2.91 J/cm 2 of exit surface. The damage morphologies are quite different between input surface and exit surface. Slow growth behavior appears for the diameter of exit-surface and linear growth one for the depth of exit-surface in the lateral side of damage site with the increase of shot number. Defects have changed obviously compared with nanosecond laser damage in the damage area. Several main reasons such as electric intensification and self-focusing for the observed initiated damage and damage growth behavior are discussed. (authors)

  5. The effect of high-flux H plasma exposure with simultaneous transient heat loads on tungsten surface damage and power handling

    Czech Academy of Sciences Publication Activity Database

    van Eden, G.G.; Morgan, T.W.; van der Meiden, H.J.; Matějíček, Jiří; Chráska, Tomáš; Wirtz, M.; De Temmerman, G.

    2014-01-01

    Roč. 54, č. 12 (2014), s. 123010-123010 ISSN 0029-5515 R&D Projects: GA ČR(CZ) GA14-12837S Institutional support: RVO:61389021 Keywords : ELMs * tungsten * thermal shock * melting * surface analysis * laser * hydrogen Subject RIV: JG - Metallurgy Impact factor: 3.062, year: 2014 http://iopscience.iop.org/0029-5515/54/12/123010/pdf/0029-5515_54_12_123010.pdf

  6. Damaged Skylab

    Science.gov (United States)

    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.

  7. Structural damage

    International Nuclear Information System (INIS)

    Gray, R.E.; Bruhn, R.W.

    1992-01-01

    Virtually all structures show some signs of distress due to deterioration of the building components, to changed loads, or to changed support conditions. Changed support conditions result from ground movements. In mining regions many cases of structural distress are attributed to mining without considering alternative causes. This is particularly true of coal mining since it occurs under extensive areas. Coal mining is estimated to have already undermined more than eight million acres and may eventually undermine 40 million acres in the United States. Other nonmetal and metal underground mines impact much smaller areas. Although it is sometimes difficult, even with careful study, to identify the actual cause of damage, persons responsible for underground coal mining should at least be aware of possible causes of building stress other than mine subsidence. This paper presents information on distress to structures and briefly reviews a number of causes of ground movements other than subsidence: Mass movements, dissolution, erosion, frost action, shrinking and swelling, yield into excavations and compressibility

  8. Depth-dependent and surface damages in MgAl sub 2 O sub 4 and MgO irradiated with energetic iodine ions

    CERN Document Server

    Aruga, T; Ohmichi, T; Okayasu, S; Kazumata, Y; Jitsukawa, S

    2002-01-01

    Samples of polycrystalline ceramics of MgAl sub 2 O sub 4 irradiated at the ambient temperature with 85 MeV I sup 7 sup + iodine ions to doses up to 1x10 sup 1 sup 9 m sup - sup 2 is observed to be amorphized up to depths around 6 mu m from the ion-incident surface for a dose of 1.2x10 sup 1 sup 9 m sup - sup 2 , through a cross-sectional transmission electron microscopy. A step height of 1 mu m is formed across the border between the masked and irradiated regions of the surface. The height of the step is observed to increase sharply from the irradiated area towards the edge at the border, forming a peak as tall as 1.5 mu m. A glossy, silver-gray film with a thickness less than 0.1 mu m is unexpectedly observed to have formed on the surface of samples of MgAl sub 2 O sub 4 and MgO, in about 3.5 years aging after the irradiation to 1.2x10 sup 1 sup 9 m sup - sup 2 , being left untouched in the air. The film is easily peeled off along grain boundaries and found to be amorphous from the electron diffraction patt...

  9. Radiation damage prediction system using damage function

    International Nuclear Information System (INIS)

    Tanaka, Yoshihisa; Mori, Seiji

    1979-01-01

    The irradiation damage analysis system using a damage function was investigated. This irradiation damage analysis system consists of the following three processes, the unfolding of a damage function, the calculation of the neutron flux spectrum of the object of damage analysis and the estimation of irradiation effect of the object of damage analysis. The damage function is calculated by applying the SAND-2 code. The ANISN and DOT3, 5 codes are used to calculate neutron flux. The neutron radiation and the allowable time of reactor operation can be estimated based on these calculations of the damage function and neutron flux. The flow diagram of the process of analyzing irradiation damage by a damage function and the flow diagram of SAND-2 code are presented, and the analytical code for estimating damage, which is determined with a damage function and a neutron spectrum, is explained. The application of the irradiation damage analysis system using a damage function was carried out to the core support structure of a fast breeder reactor for the damage estimation and the uncertainty evaluation. The fundamental analytical conditions and the analytical model for this work are presented, then the irradiation data for SUS304, the initial estimated values of a damage function, the error analysis for a damage function and the analytical results are explained concerning the computation of a damage function for 10% total elongation. Concerning the damage estimation of FBR core support structure, the standard and lower limiting values of damage, the permissible neutron flux and the allowable years of reactor operation are presented and were evaluated. (Nakai, Y.)

  10. Fatigue damage evaluation method for the longitudinal welded joint of a FBR main vessel in the vicinity of the sodium surface

    International Nuclear Information System (INIS)

    Tanigawa, Masayuki; Shimokoshi, Minoru; Negishi, Hitoshi; Nagata, Takashi

    1990-01-01

    Metallurgical discontinuities are dominant in the fatigue strength reductions at the welded joints of vessels whose surfaces could be finished. In the welded joints of SUS 304 with TYPE 308 weld metal fatigue strength reductions are caused by strain concentrations as the result of the softening of the weld metal. A combination model of two elastic fully plastic materials is applicable to the structures under thermal stresses where displacements are self-controlled. Metallurgical discontinuities are represented by the difference of the yield strength. The longitudinal welded joint of a large FBR main vessel in the vicinity of the sodium surface was analyzed using this model under various conditions related to the design. Strain concentrations at the welded joint could be evaluated using the elastic follow-up model. The maximum value of the elastic follow-up parameter was 3.0 if the yield stress ratio of the weld metal to the base metal was not less than 0.8. (author)

  11. A Model for Creep and Creep Damage in the γ-Titanium Aluminide Ti-45Al-2Mn-2Nb.

    Science.gov (United States)

    Harrison, William; Abdallah, Zakaria; Whittaker, Mark

    2014-03-14

    Gamma titanium aluminides (γ-TiAl) display significantly improved high temperature mechanical properties over conventional titanium alloys. Due to their low densities, these alloys are increasingly becoming strong candidates to replace nickel-base superalloys in future gas turbine aeroengine components. To determine the safe operating life of such components, a good understanding of their creep properties is essential. Of particular importance to gas turbine component design is the ability to accurately predict the rate of accumulation of creep strain to ensure that excessive deformation does not occur during the component's service life and to quantify the effects of creep on fatigue life. The theta (θ) projection technique is an illustrative example of a creep curve method which has, in this paper, been utilised to accurately represent the creep behaviour of the γ-TiAl alloy Ti -45Al-2Mn-2Nb. Furthermore, a continuum damage approach based on the θ-projection method has also been used to represent tertiary creep damage and accurately predict creep rupture.

  12. Unsteady Reynolds-averaged Navier-Stokes simulations of inlet distortion in the fan system of a gas-turbine aero-engine

    Science.gov (United States)

    Spotts, Nathan

    As modern trends in commercial aircraft design move toward high-bypass-ratio fan systems of increasing diameter with shorter, nonaxisymmetric nacelle geometries, inlet distortion is becoming common in all operating regimes. The distortion may induce aerodynamic instabilities within the fan system, leading to catastrophic damage to fan blades, should the surge margin be exceeded. Even in the absence of system instability, the heterogeneity of the flow affects aerodynamic performance significantly. Therefore, an understanding of fan-distortion interaction is critical to aircraft engine system design. This thesis research elucidates the complex fluid dynamics and fan-distortion interaction by means of computational fluid dynamics (CFD) modeling of a complete engine fan system; including rotor, stator, spinner, nacelle and nozzle; under conditions typical of those encountered by commercial aircraft. The CFD simulations, based on a Reynolds-averaged Navier-Stokes (RANS) approach, were unsteady, three-dimensional, and of a full-annulus geometry. A thorough, systematic validation has been performed for configurations from a single passage of a rotor to a full-annulus system by comparing the predicted flow characteristics and aerodynamic performance to those found in literature. The original contributions of this research include the integration of a complete engine fan system, based on the NASA rotor 67 transonic stage and representative of the propulsion systems in commercial aircraft, and a benchmark case for unsteady RANS simulations of distorted flow in such a geometry under realistic operating conditions. This study is unique in that the complex flow dynamics, resulting from fan-distortion interaction, were illustrated in a practical geometry under realistic operating conditions. For example, the compressive stage is shown to influence upstream static pressure distributions and thus suppress separation of flow on the nacelle. Knowledge of such flow physics is

  13. Improvement of interfacial adhesion and nondestructive damage evaluation for plasma-treated PBO and Kevlar fibers/epoxy composites using micromechanical techniques and surface wettability.

    Science.gov (United States)

    Park, Joung-Man; Kim, Dae-Sik; Kim, Sung-Ryong

    2003-08-15

    Comparison of interfacial properties and microfailure mechanisms of oxygen-plasma treated poly(p-phenylene-2,6-benzobisoxazole (PBO, Zylon) and poly(p-phenylene terephthalamide) (PPTA, Kevlar) fibers/epoxy composites were investigated using a micromechanical technique and nondestructive acoustic emission (AE). The interfacial shear strength (IFSS) and work of adhesion, Wa, of PBO or Kevlar fiber/epoxy composites increased with oxygen-plasma treatment, due to induced hydrogen and covalent bondings at their interface. Plasma-treated Kevlar fiber showed the maximum critical surface tension and polar term, whereas the untreated PBO fiber showed the minimum values. The work of adhesion and the polar term were proportional to the IFSS directly for both PBO and Kevlar fibers. The microfibril fracture pattern of two plasma-treated fibers appeared obviously. Unlike in slow cooling, in rapid cooling, case kink band and kicking in PBO fiber appeared, whereas buckling in the Kevlar fiber was observed mainly due to compressive and residual stresses. Based on the propagation of microfibril failure toward the core region, the number of AE events for plasma-treated PBO and Kevlar fibers increased significantly compared to the untreated case. The results of nondestructive AE were consistent with microfailure modes.

  14. Damage detection in high-rise buildings using damage-induced rotations

    International Nuclear Information System (INIS)

    Sung, Seung Hun; Jung, Ho Youn; Lee, Jung Hoon; Jung, Hyung Jo

    2016-01-01

    In this paper, a new damage-detection method based on structural vibration is proposed. The essence of the proposed method is the detection of abrupt changes in rotation. Damage-induced rotation (DIR), which is determined from the modal flexibility of the structure, initially occurs only at a specific damaged location. Therefore, damage can be localized by evaluating abrupt changes in rotation. We conducted numerical simulations of two damage scenarios using a 10-story cantilever-type building model. Measurement noise was also considered in the simulation. We compared the sensitivity of the proposed method to localize damage to that of two conventional modal-flexibility-based damage-detection methods, i.e., uniform load surface (ULS) and ULS curvature. The proposed method was able to localize damage in both damage scenarios for cantilever structures, but the conventional methods could not

  15. Damage detection in high-rise buildings using damage-induced rotations

    International Nuclear Information System (INIS)

    Sung, Seung Hoon; Jung, Ho Youn; Lee, Jung Hoon; Jung, Hyung Jo

    2014-01-01

    In this paper, a new damage-detection method based on structural vibration is proposed. The essence of the proposed method is the detection of abrupt changes in rotation. Damage-induced rotation (DIR), which is determined from the modal flexibility of the structure, initially occurs only at a specific damaged location. Therefore, damage can be localized by evaluating abrupt changes in rotation. We conducted numerical simulations of two damage scenarios using a 10-story cantilever-type building model. Measurement noise was also considered in the simulation. We compared the sensitivity of the proposed method to localize damage to that of two conventional modal-flexibility-based damage-detection methods, i.e., uniform load surface (ULS) and ULS curvature. The proposed method was able to localize damage in both damage scenarios for cantilever structures, but the conventional methods could not.

  16. Pulsed laser damage to optical fibers

    International Nuclear Information System (INIS)

    Allison, S.W.; Gillies, G.T.; Magnuson, D.W.; Pagano, T.S.

    1985-01-01

    This paper describes some observations of pulsed laser damage to optical fibers with emphasis on a damage mode characterized as a linear fracture along the outer core of a fiber. Damage threshold data are presented which illustrate the effects of the focusing lens, end-surface preparation, and type of fiber. An explanation based on fiber-beam misalignment is given and is illustrated by a simple experiment and ray trace

  17. 7 CFR 51.2294 - Very serious damage.

    Science.gov (United States)

    2010-01-01

    ... serious damage. Very serious damage means any defect, other than color, which very seriously affects the... than one-fourth of the surface of the portion of kernel in the aggregate; (c) Discoloration of the meat...

  18. 7 CFR 51.1323 - Serious damage.

    Science.gov (United States)

    2010-01-01

    ... frost injury, 15 percent of the surface. (3) On Anjou, smooth solid or smooth netlike russeting when the... Standards for Winter Pears 1 Definitions § 51.1323 Serious damage. Serious damage means any injury or defect...) Drought spot when more than two in number, or where the external injury affects an aggregate area of more...

  19. Small Optics Laser Damage Test Procedure

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, Justin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-10-19

    This specification defines the requirements and procedure for laser damage testing of coatings and bare surfaces designated for small optics in the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL).

  20. Damage analysis: damage function development and application

    International Nuclear Information System (INIS)

    Simons, R.L.; Odette, G.R.

    1975-01-01

    The derivation and application of damage functions, including recent developments for the U.S. LMFBR and CTR programs, is reviewed. A primary application of damage functions is in predicting component life expectancies; i.e., the fluence required in a service spectrum to attain a specified design property change. An important part of the analysis is the estimation of the uncertainty in such fluence limit predictions. The status of standardizing the procedures for the derivation and application of damage functions is discussed. Improvements in several areas of damage function development are needed before standardization can be completed. These include increasing the quantity and quality of the data used in the analysis, determining the limitations of the analysis due to the presence of multiple damage mechanisms, and finally, testing of damage function predictions against data obtained from material surveillance programs in operating thermal and fast reactors. 23 references. (auth)

  1. Laser-induced damage in optical materials

    CERN Document Server

    Ristau, Detlev

    2014-01-01

    Dedicated to users and developers of high-powered systems, Laser-Induced Damage in Optical Materials focuses on the research field of laser-induced damage and explores the significant and steady growth of applications for high-power lasers in the academic, industrial, and military arenas. Written by renowned experts in the field, this book concentrates on the major topics of laser-induced damage in optical materials and most specifically addresses research in laser damage that occurs in the bulk and on the surface or the coating of optical components. It considers key issues in the field of hi

  2. Cleaner aero-engines taking off

    International Nuclear Information System (INIS)

    Lothigius, J.

    1991-01-01

    Airlines operating on domestic routes in Sweden have to pay taxes on their emissions of nitrogen oxides, hydrocarbons and carbon dioxide. These taxes have spurred improvements in engine design, but are unlikely to slow the growth in air traffic

  3. Radiation damage of nonmetallic solids

    International Nuclear Information System (INIS)

    Goland, A.N.

    1975-01-01

    A review of data and information on radiation damage in nonmetallic solids is presented. Discussions are included on defects in nonmetals, radiation damage processes in nonmetals, electronic damage processes, physical damage processes, atomic displacement, photochemical damage processes, and ion implantation

  4. Femoral nerve damage (image)

    Science.gov (United States)

    The femoral nerve is located in the leg and supplies the muscles that assist help straighten the leg. It supplies sensation ... leg. One risk of damage to the femoral nerve is pelvic fracture. Symptoms of femoral nerve damage ...

  5. Damage Detection/Locating System Providing Thermal Protection

    Science.gov (United States)

    Woodard, Stanley E. (Inventor); Jones, Thomas W. (Inventor); Taylor, Bryant D. (Inventor); Qamar, A. Shams (Inventor)

    2010-01-01

    A damage locating system also provides thermal protection. An array of sensors substantially tiles an area of interest. Each sensor is a reflective-surface conductor having operatively coupled inductance and capacitance. A magnetic field response recorder is provided to interrogate each sensor before and after a damage condition. Changes in response are indicative of damage and a corresponding location thereof.

  6. Damage Localization of Severely Damaged RC-Structures Based on Measured Eigenperiods from a Single Response

    DEFF Research Database (Denmark)

    Skjærbæk, P. S.; Nielsen, Søren R.K.; Cakmak, A. S.

    This paper deals with the estimation of the damage location of severely damaged Reinforced Concrete (RC) structures excited by earthquakes. It is assumed that the building is instrumented with a sensor measuring the earthquake acceleration signal at ground surface and a sensor measuring only...

  7. A broader classification of damage zones

    Science.gov (United States)

    Peacock, D. C. P.; Dimmen, V.; Rotevatn, A.; Sanderson, D. J.

    2017-09-01

    Damage zones have previously been classified in terms of their positions at fault tips, walls or areas of linkage, with the latter being described in terms of sub-parallel and synchronously active faults. We broaden the idea of linkage to include structures around the intersections of non-parallel and/or non-synchronous faults. These interaction damage zones can be divided into approaching damage zones, where the faults kinematically interact but are not physically connected, and intersection damage zones, where the faults either abut or cross-cut. The damage zone concept is applied to other settings in which strain or displacement variations are taken up by a range of structures, such as at fault bends. It is recommended that a prefix can be added to a wide range of damage zones, to describe the locations in which they formed, e.g., approaching, intersection and fault bend damage zone. Such interpretations are commonly based on limited knowledge of the 3D geometries of the structures, such as from exposure surfaces, and there may be spatial variations. For example, approaching faults and related damage seen in outcrop may be intersecting elsewhere on the fault planes. Dilation in intersection damage zones can represent narrow and localised channels for fluid flow, and such dilation can be influenced by post-faulting stress patterns.

  8. Pollution Damage and Protection of Asian Hair

    Directory of Open Access Journals (Sweden)

    Xin Qu

    2018-02-01

    Full Text Available Cigarette smoke was used to simulate a polluted environment and an experiment was performed to reveal how virgin and bleached hair are damaged by a polluted environment. The dry/wet combability, surface contact angle, tryptophan content, and cuticle morphology of the smoke exposed hair were evaluated, and compared to unexposed virgin hair. The results showed that pollution exposure can cause significant chemical damage to hair. In particular, virgin hair exposure to pollution can cause damage to the hair cuticles (higher wet/dry combing, protein degradation, and a more hydrophilic hair surface. The experiment also demonstrated that the styling polymer, polyimide-1 (isobutylene/dimethyl amino propyl maleimide/ethoxylated maleimide/maleic acid copolymer, can provide effective protection against such hair damage.

  9. Fatigue damage monitoring of structural aluminum alloys

    Directory of Open Access Journals (Sweden)

    С.Р. Ігнатович

    2004-01-01

    Full Text Available  Results of the experiments directed on creation of a new tool method of fatigue damage diagnostics and an estimation of a residual life of aviation designs are presented. It is shown, that the defo rmation relief formed on a surface of cladding  layer of sheets of constructional alloys Д-16АТ, 2024-Т3, 7075-Т6  can be considered as the metal damage indicator  under cyclically repeating loadings.

  10. Radiation damage to mushrooms

    International Nuclear Information System (INIS)

    Sattler, P.W.

    1986-01-01

    This document contains newspaper cuttings and correspondence with various ministries in Hessen on the subject of radiation damage to mushrooms from the Odenwald area. The reader is given, amongst other things, detailed information on radiation damage to different types of mushroom in 1986. (MG) [de

  11. Animal damage to birch

    Science.gov (United States)

    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. Animal damage management handbook.

    Science.gov (United States)

    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...

  13. Nuclear damage - civil liability

    International Nuclear Information System (INIS)

    Simoes, A.C.

    1980-01-01

    An analysis is made of the civil liability for nuclear damage since there is a need to adjust the existing rules to the new situations created. The conventions that set up the new disciplining rules not considered in the common law for the liability of nuclear damage are also mentioned. (A.L.) [pt

  14. DNA damage and autophagy

    International Nuclear Information System (INIS)

    Rodriguez-Rocha, Humberto; Garcia-Garcia, Aracely; Panayiotidis, Mihalis I.; Franco, Rodrigo

    2011-01-01

    Both exogenous and endogenous agents are a threat to DNA integrity. Exogenous environmental agents such as ultraviolet (UV) and ionizing radiation, genotoxic chemicals and endogenous byproducts of metabolism including reactive oxygen species can cause alterations in DNA structure (DNA damage). Unrepaired DNA damage has been linked to a variety of human disorders including cancer and neurodegenerative disease. Thus, efficient mechanisms to detect DNA lesions, signal their presence and promote their repair have been evolved in cells. If DNA is effectively repaired, DNA damage response is inactivated and normal cell functioning resumes. In contrast, when DNA lesions cannot be removed, chronic DNA damage triggers specific cell responses such as cell death and senescence. Recently, DNA damage has been shown to induce autophagy, a cellular catabolic process that maintains a balance between synthesis, degradation, and recycling of cellular components. But the exact mechanisms by which DNA damage triggers autophagy are unclear. More importantly, the role of autophagy in the DNA damage response and cellular fate is unknown. In this review we analyze evidence that supports a role for autophagy as an integral part of the DNA damage response.

  15. Metabolite Damage and Metabolite Damage Control in Plants

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, Andrew D. [Horticultural Sciences Department and; Henry, Christopher S. [Mathematics and Computer Science Division, Argonne National Laboratory, Argonne, Illinois 60439, email:; Computation Institute, University of Chicago, Chicago, Illinois 60637; Fiehn, Oliver [Genome Center, University of California, Davis, California 95616, email:; de Crécy-Lagard, Valérie [Microbiology and Cell Science Department, University of Florida, Gainesville, Florida 32611, email: ,

    2016-04-29

    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.

  16. DNA damage and polyploidization.

    Science.gov (United States)

    Chow, Jeremy; Poon, Randy Y C

    2010-01-01

    A growing body of evidence indicates that polyploidization triggers chromosomal instability and contributes to tumorigenesis. DNA damage is increasingly being recognized for its roles in promoting polyploidization. Although elegant mechanisms known as the DNA damage checkpoints are responsible for halting the cell cycle after DNA damage, agents that uncouple the checkpoints can induce unscheduled entry into mitosis. Likewise, defects of the checkpoints in several disorders permit mitotic entry even in the presence of DNA damage. Forcing cells with damaged DNA into mitosis causes severe chromosome segregation defects, including lagging chromosomes, chromosomal fragments and chromosomal bridges. The presence of these lesions in the cleavage plane is believed to abort cytokinesis. It is postulated that if cytokinesis failure is coupled with defects of the p53-dependent postmitotic checkpoint pathway, cells can enter S phase and become polyploids. Progress in the past several years has unraveled some of the underlying principles of these pathways and underscored the important role of DNA damage in polyploidization. Furthermore, polyploidization per se may also be an important determinant of sensitivity to DNA damage, thereby may offer an opportunity for novel therapies.

  17. Method to reduce damage to backing plate

    Science.gov (United States)

    Perry, Michael D.; Banks, Paul S.; Stuart, Brent C.

    2001-01-01

    The present invention is a method for penetrating a workpiece using an ultra-short pulse laser beam without causing damage to subsequent surfaces facing the laser. Several embodiments are shown which place holes in fuel injectors without damaging the back surface of the sack in which the fuel is ejected. In one embodiment, pulses from an ultra short pulse laser remove about 10 nm to 1000 nm of material per pulse. In one embodiment, a plasma source is attached to the fuel injector and initiated by common methods such as microwave energy. In another embodiment of the invention, the sack void is filled with a solid. In one other embodiment, a high viscosity liquid is placed within the sack. In general, high-viscosity liquids preferably used in this invention should have a high damage threshold and have a diffusing property.

  18. Cantilever steel post damaged by wind

    Directory of Open Access Journals (Sweden)

    Wei Sha

    2014-10-01

    Full Text Available An analysis for the cause of fracture failure of a cantilever steel sign post damaged by wind has been carried out. An unusual cause of failure has been identified, which is the subject of this paper. Microscopy and microanalysis of the fracture surface showed that the failure was due to pre-existing cracks, from the fabrication of the post. This conclusion was reached after detecting and analysing a galvanised layer on the fracture surfaces.

  19. LSD and Genetic Damage

    Science.gov (United States)

    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)

  20. Diabetes and nerve damage

    Science.gov (United States)

    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 ...

  1. Frost damage of concrete subject to confinement

    DEFF Research Database (Denmark)

    Hasholt, Marianne Tange

    2016-01-01

    When internal frost damage is observed in real concrete structures, the usual pattern is cracks with a preferred orientation parallel to the exposed surface. When exposing concrete with poor frost resistance to a standardised freeze/thaw test in the laboratory, the orientations of the resulting...

  2. Integrated geomechanical modelling for deep subsurface damage

    NARCIS (Netherlands)

    Wees, J.D. van; Orlic, B.; Zijl, W.; Jongerius, P.; Schreppers, G.J.; Hendriks, M.

    2001-01-01

    Government, E&P and mining industry increasingly demand fundamental insight and accurate predictions on subsurface and surface deformation and damage due to exploitation of subsurface natural resources, and subsurface storage of energy residues (e.g. CO2). At this moment deformation is difficult to

  3. Laser-Induced Damage with Femtosecond Pulses

    Science.gov (United States)

    Kafka, Kyle R. P.

    The strong electric fields of focused femtosecond laser pulses lead to non-equilibrium dynamics in materials, which, beyond a threshold intensity, causes laser-induced damage (LID). Such a strongly non-linear and non-perturbative process renders important LID observables like fluence and intensity thresholds and damage morphology (crater) extremely difficult to predict quantitatively. However, femtosecond LID carries a high degree of precision, which has been exploited in various micro/nano-machining and surface engineering applications, such as human eye surgery and super-hydrophobic surfaces. This dissertation presents an array of experimental studies which have measured the damage behavior of various materials under femtosecond irradiation. Precision experiments were performed to produce extreme spatio-temporal confinement of the femtosecond laser-solid damage interaction on monocrystalline Cu, which made possible the first successful direct-benchmarking of LID simulation with realistic damage craters. A technique was developed to produce laser-induced periodic surface structures (LIPSS) in a single pulse (typically a multi-pulse phenomenon), and was used to perform a pump-probe study which revealed asynchronous LIPSS formation on copper. Combined with 1-D calculations, this new experimental result suggests more drastic electron heating than expected. Few-cycle pulses were used to study the LID performance and morphology of commercial ultra-broadband optics, which had not been systematically studied before. With extensive surface analysis, various morphologies were observed, including LIPSS, swelling (blisters), simple craters, and even ring-shaped structures, which varied depending on the coating design, number of pulses, and air/vacuum test environment. Mechanisms leading to these morphologies are discussed, many of which are ultrafast in nature. The applied damage behavior of multi-layer dielectric mirrors was measured and compared between long pulse (150 ps

  4. Compression of laminated composite beams with initial damage

    Science.gov (United States)

    Breivik, Nicole L.; Gurdal, Zafer; Griffin, O. H., Jr.

    1993-01-01

    The effect of isolated damage modes on the compressive strength and failure characteristics of laminated composite test specimens were evaluated experimentally and numerically. In addition to specimens without initial damage, specimens with three types of initial damage were considered: (1) specimens with short delaminations distributed evenly through the specimen thickness, (2) specimens with few long delaminations, and (3) specimens with local fiber damage in the surface plies under the three-point bend contact point. It was found that specimens with short multiple delamination experienced the greatest reduction in compression strength compared to the undamaged specimens. Single delaminations far from the specimen surface had little effect on the final compression strength, and moderate strength reduction was observed for specimens with localized surface ply damage.

  5. Damage symptoms of plants due to PAN exposure

    Energy Technology Data Exchange (ETDEWEB)

    Nouchi, I; Sawada, T; Ohashi, T; Odaira, T

    1974-11-01

    In order to identify the cause of plant damage which differed from that by ozone, a series of exposure experiments was carried out on Beta vulgaris, Japanese radish, French bean, luthern, tomato, and spinach in a controlled weather room by artificially synthesized PAN (peroxyacetyl nitrate). The damage appeared generally on younger leaves as a lustering and bronzing on the lower surface; there was a specific symptom in which the interveinary part of the lower surface depressed, leaving the veins in relief. At higher concentrations of PAN, damages appeared on the upper surface of leaves, however, bronzing and lustering were clearer during exposure to lower concentrations of PAN. The position of the leaves and the part of a leaf which was damaged were constant in the petunia, morning glory, and tobacco. There was a hyperbolic relationship between the concentration of PAN and the time period of appearance of the damage as was seen during sulfur dioxide and ozone exposures.

  6. Measurement of radiation damage on an optical reflector

    International Nuclear Information System (INIS)

    Peng, K.C.; Sahu, S.K.; Huang, H.C.; Ueno, K.; Chang, Y.H.; Wang, C.H.; Hou, W.S.

    1997-01-01

    We measured the radiation damage on an optical white fluorocarbon reflector called Goretex, which is to be used for aerogel threshold counters and crystal calorimeters of the BELLE detector of the KEK B-factory. Reflectance of the Goretex surface was monitored to see any effect of the radiation damage. Maximum equivalent dose was 8.6 Mrad. No radiation damage is observed within measurement errors. (orig.)

  7. Ion damage calculations in crystalline silicon

    International Nuclear Information System (INIS)

    Oen, O.S.

    1985-07-01

    Damage profiles in crystalline silicon produced by light (B) and heavy (Bi) ions with energies from 10 to 100 keV were studied using the computer program MARLOWE (version 12). The program follows not only the incident ion collision by collision, but also any Si target atom that is set into motion through an energetic collision. Thus, the transport effect of the complete cascade of recoiled target atoms is included in the damage profile. The influence of channeling was studied for Si(100) using beam tilt angles from the surface normal of 0 0 , 3 0 and 7 0 about the [001] or [011] axes. The effects of channeling on the damage profile are twofold: first, there is a large reduction of the central damage peak; second, there is a component of the damage profile that extends considerably deeper into the target than that found in conventional studies using a random target assemblage. The influence of amorphous overlayers of SiO 2 on the damage and implantation profiles in the Si(100) substrate has also been investigated

  8. Natural resource damage assessment

    International Nuclear Information System (INIS)

    Seddelmeyer, J.

    1991-01-01

    The assessment and collection of natural resource damages from petroleum and chemical companies unfortunate enough to have injured publicly owned natural resources is perhaps the most rapidly expanding area of environmental liability. The idea of recovering for injury to publicly owned natural resources is an extension of traditional common law tort concepts under which a person who negligently injures another or his property is called upon to compensate the injured party. Normally, once liability has been established, it is a fairly straightforward matter to calculate the various elements of loss, such as the cost to repair or replace damaged property, or medical expenses, and lost income. More difficult questions, such as the amount to be awarded for pain and suffering or emotional distress, are left to the jury, although courts limit the circumstances in which the jury is permitted to award such damages

  9. Detection of laser damage by Raman microscopy

    International Nuclear Information System (INIS)

    Fauchet, P.M.; Campbell, I.H.; Adar, F.

    1988-01-01

    The authors demonstrate that Raman miroscopy is a sensitive and quantitative tool to detect and characterize laser-induced damage in solids. After damage is induced with single or multiple high power laser pulses, a Raman microprobe maps the surface of the sample with one micron spatial resolution. By performing accurate measurements of the Stokes line, the authors have been able to measure stress, strain and crystallinity in various samples which had been exposed to high intensity pulses. These results are compared to those obtained using conventional tools such as Nomarski microscopy. Major advantages of Raman microscopy include sensitivity to subtle structural modifications and the fact that it gives quantitative measurements

  10. Failure and damage analysis of advanced materials

    CERN Document Server

    Sadowski, Tomasz

    2015-01-01

    The papers in this volume present basic concepts and new developments in failure and damage analysis with focus on advanced materials such as composites, laminates, sandwiches and foams, and also new metallic materials. Starting from some mathematical foundations (limit surfaces, symmetry considerations, invariants) new experimental results and their analysis are shown. Finally, new concepts for failure prediction and analysis will be introduced and discussed as well as new methods of failure and damage prediction for advanced metallic and non-metallic materials. Based on experimental results the traditional methods will be revised.

  11. Density of oxidation-induced stacking faults in damaged silicon

    NARCIS (Netherlands)

    Kuper, F.G.; Hosson, J.Th.M. De; Verwey, J.F.

    1986-01-01

    A model for the relation between density and length of oxidation-induced stacking faults on damaged silicon surfaces is proposed, based on interactions of stacking faults with dislocations and neighboring stacking faults. The model agrees with experiments.

  12. Nondestructive characterization of materials damage

    International Nuclear Information System (INIS)

    Dobmann, G.

    1999-01-01

    The paper discusses two examples of application of NDT for early detection of materials damage, or ageing effects. The first case shows the potential of micromagnetic testing techniques for early detection of hydrogen-induced stress corrosion cracking in pipework. Pipe specimens made of steel X20Cr13, which differed in materials state induced by various heat treatments, were exposed to corrosive attack induced in a closed cycle by simultaneous rinsing with NACE solution and stress application through stamp impact. Various micromagnetic testing parameters were measured at the specimens' outside surface during the annealing period. Further, fatigue experiments were made with specimen sets made of steel 1.4541, under various mechanical and temperature stresses (room temperature and 300 C), for measuring the remanent magnetization of the cylindrical fatigue test blocks (equal geometry) cut out of the specimens, in order to conclude information on the martensite content and the fatigue effects. (Orig./CB) [de

  13. mapDamage

    DEFF Research Database (Denmark)

    Ginolhac, Aurélien; Rasmussen, Morten; Gilbert, Tom

    2011-01-01

    Ancient DNA extracts consist of a mixture of contaminant DNA molecules, most often originating from environmental microbes, and endogenous fragments exhibiting substantial levels of DNA damage. The latter introduce specific nucleotide misincorporations and DNA fragmentation signatures in sequenci...... of the SAMtools suite and R environment and has been validated on both GNU/Linux and MacOSX operating systems....

  14. Core damage risk indicators

    International Nuclear Information System (INIS)

    Szikszai, T.

    1994-01-01

    The purpose of this document is to show a method for the fast recalculation of the PSA. To avoid the information loose, it is necessary to simplify the PSA models, or at least reorganize them. The method, introduced in this document, require that preparation, so we try to show, how to do that. This document is an introduction. This is the starting point of the work related to the development of the risk indicators. In the future, with the application of this method, we are going to show an everyday use of the PSA results to produce the indicators of the core damage risk. There are two different indicators of the plant safety performance, related to the core damage risk. The first is the core damage frequency indicator (CDFI), and the second is the core damage probability indicator (CDPI). Of course, we cannot describe all of the possible ways to use these indicators, rather we will try to introduce the requirements to establish such an indicator system and the calculation process

  15. Risk of nuclear damage

    International Nuclear Information System (INIS)

    Kienzl, K.

    1997-01-01

    Following the opening and words of welcome by Mr. Fritz Unterpertinger (unit director at the Austrian Federal Ministry for the Environment, Youth and Family; BMUJF) Mrs Helga Kromp-Kolb (professor at the Institute for Meteorology and Physics of the University of Natural Resources Science Vienna) illustrated the risks of nuclear damage in Europe by means of a nuclear risk map. She explained that even from a scientific or technical point of view the assessment of risks arising from nuclear power stations was fraught with great uncertainties. Estimates about in how far MCAs (maximum credible accident) could still be controlled by safety systems vary widely and so do assessments of the probability of a core melt. But there is wide agreement in all risk assessments conducted so far that MCAs might occur within a - from a human point of view - conceivable number of years. In this connection one has to bear in mind that the occurrence of such a major accident - whatever its probability may be - could entail immense damage and the question arises whether or not it is at all justifiable to expose the general public to such a risk. Klaus Rennings (Centre for European Economic Research, Mannheim, Germany) dealt with the economic aspects of nuclear risk assessment. He explained that there are already a number of studies available aiming to assess the risk of damage resulting from a core melt accident in economic terms. As to the probability of occurrence estimates vary widely between one incident in 3,333 and 250,000 year of reactor operation. It is assumed, however, that a nuclear accident involving a core melt in Germany would probably exceed the damage caused by the Chernobyl accident. The following speakers addressed the legal aspects of risks associated with nuclear installations. Mrs Monika Gimpel-Hinteregger (professor at the Institute for Civil Law in Graz) gave an overview on the applicable Austrian law concerning third party liability in the field of nuclear energy

  16. Wavelet Transformation for Damage Identication in Wind Turbine Blades

    DEFF Research Database (Denmark)

    Ulriksen, Martin Dalgaard; Skov, Jonas falk; Kirkegaard, Poul Henning

    2014-01-01

    The present paper documents a proposed modal and wavelet analysis-based structural health monitoring (SHM) method for damage identification in wind turbine blades. A finite element (FE) model of a full-scale wind turbine blade is developed and introduced to a transverse surface crack. Hereby, post......-damage mode shapes are derived through modal analysis and subsequently analyzed with continuous two-dimensional wavelet transformation for damage identification, namely detection, localization and assessment. It is found that valid damage identification is obtained even when utilizing the mode shape...

  17. Fabrication of Cheap Optical Transducers (CHOTs) on film carriers for in-situ application and generation of surface acoustic waves

    International Nuclear Information System (INIS)

    Ageeva, V; Stratoudaki, T; Clark, M; Somekh, M G

    2015-01-01

    Cheap optical transducers (CHOTs) are patterns on the surface of a component activated by lasers to generate and detect ultrasound. Excited optically, with minimal surface impact, and fully customizable, CHOTs provide a simple alternative to conventional piezoelectric transducers, offering wireless, remote operation. Of particular interest is application of CHOTs for in-situ ultrasonic inspection of hard-to reach and complex-geometry components such as those of aero-engines. A suitable fabrication method has been developed to allow in-situ application of CHOTs onto large size and curved components, as well as those already in service, challenging for current laboratory-based micro-patterning methods. This work describes the fabrication of a transferable g-CHOT for generation of ultrasound. The g- CHOT has been made on an SU8 carrier film using a sacrificial polystyrene layer, allowing the transducer to be transferred from the substrate and subsequently delivered and applied to the surface of the sample in-situ. The functionality of the fabricated transducer is demonstrated by detection of the Surface Acoustic Waves (SAW) generated by the g-CHOT transferred onto glass and aluminium samples

  18. Development of a nondestructive testing method and facility for investigation of surface reactions appearing in damage, corrosion, adsorption and catalytic processes encountered in the heat transfer systems of nuclear power plants and the energy storage problems

    International Nuclear Information System (INIS)

    Gumhalter, G.

    1986-08-01

    Studies of corrosion, oxide layer growth, etc., necessitate the investigation of processes which take place at surfaces: adsorption and desorption. Two problems are of major importance: i) initial stages of oxidative attack, e.g. the adsorptive properties of oxygen for a given system and possible synergetic effects of coadsorbed species like CO, H 2 O, OH, H 2 , SH 2 , impurities, and ii) the influence of surface conditions (crystalography, defects, pores, impurities, segregates) on the oxidative attack. An apparatus has been developed with three surface sensitive techniques: a) quartzcrystal micro-balance as a method for measuring the kinetics of deposition of thin metal films and gas adsorption, b) diode probe for the measurement of work function change caused by gas adsorption at metallic surfaces, and c) thermal desorption spectroscopy (TDS) which gives information on adsorption/desorption properties of a system studied: activation energy, preexponential factors for desorption, coverage, precursor states, lateral interaction, etc. The system investigated was oxygen/palladium foil (polycrystalline) by means of TDS and the following conclusions have been drawn: 1. Oxygen adsorbs on Pd foil both dissociatively and nondissociatively - depending on the adsorption temperature. 2. Certain amounts of oxygen penetrates into the surface and subsurface region, giving rise to a desorption peak around 1350K. 3. There are two groups of desorption peaks corresponding to atomically adsorbed oxygen (730K and 800K). The analysis of these peaks show the existence of strong lateral interactions between oxygen atoms at high coverages, which is not the case for low coverages. The position of the peaks and the dynamics of their evolution is consistent with the data obtained for Pd(111) and Pd(100) single crystal surfaces

  19. Numerical and Experimental Validation of a New Damage Initiation Criterion

    Science.gov (United States)

    Sadhinoch, M.; Atzema, E. H.; Perdahcioglu, E. S.; van den Boogaard, A. H.

    2017-09-01

    Most commercial finite element software packages, like Abaqus, have a built-in coupled damage model where a damage evolution needs to be defined in terms of a single fracture energy value for all stress states. The Johnson-Cook criterion has been modified to be Lode parameter dependent and this Modified Johnson-Cook (MJC) criterion is used as a Damage Initiation Surface (DIS) in combination with the built-in Abaqus ductile damage model. An exponential damage evolution law has been used with a single fracture energy value. Ultimately, the simulated force-displacement curves are compared with experiments to validate the MJC criterion. 7 out of 9 fracture experiments were predicted accurately. The limitations and accuracy of the failure predictions of the newly developed damage initiation criterion will be discussed shortly.

  20. Immunoassay of DNA damage

    International Nuclear Information System (INIS)

    Gasparro, F.P.; Santella, R.M.

    1988-01-01

    The direct photomodification of DNA by ultraviolet light or the photo-induced addition of exogenous compounds to DNA components results in alterations of DNA structure ranging from subtle to profound. There are two consequences of these conformational changes. First, cells in which the DNA has been damaged are capable of executing repair steps. Second, the DNA which is usually of very low immunogenicity now becomes highly antigenic. This latter property has allowed the production of a series of monoclonal antibodies that recognize photo-induced DNA damage. Monoclonal antibodies have been generated that recognize the 4',5'-monoadduct and the crosslink of 8-methoxypsoralen in DNA. In addition, another antibody has been prepared which recognizes the furan-side monoadduct of 6,4,4'-trimethylangelicin in DNA. These monoclonal antibodies have been characterized as to sensitivity and specificity using non-competitive and competitive enzyme-linked-immunosorbent assays (ELISA). (author)

  1. Neutron induced radiation damage

    International Nuclear Information System (INIS)

    Williams, M.M.R.

    1977-01-01

    We derive a general expression for the number of displaced atoms of type j caused by a primary knock-on of type i. The Kinchin-Pease model is used, but considerably generalised to allow for realistic atomic potentials. Two cases are considered in detail: the single particle problem causing a cascade and the neutron initiated problem which leads to multiple subcascades. Numerical results have been obtained for a variety of scattering laws. An important conclusion is that neutron initiated damage is much more severe than atom-initiated damage and leads to the number of displaced atoms being a factor of (A+1) 2 /4A larger than the single primary knock-on theory predicts. A is the ratio of the atomic mass to the neutron mass. The importance of this result to the theory of neutron sputtering is explained. (orig.) [de

  2. Immunoassay of DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Gasparro, F P; Santella, R M

    1988-09-01

    The direct photomodification of DNA by ultraviolet light or the photo-induced addition of exogenous compounds to DNA components results in alterations of DNA structure ranging from subtle to profound. There are two consequences of these conformational changes. First, cells in which the DNA has been damaged are capable of executing repair steps. Second, the DNA which is usually of very low immunogenicity now becomes highly antigenic. This latter property has allowed the production of a series of monoclonal antibodies that recognize photo-induced DNA damage. Monoclonal antibodies have been generated that recognize the 4',5'-monoadduct and the crosslink of 8-methoxypsoralen in DNA. In addition, another antibody has been prepared which recognizes the furan-side monoadduct of 6,4,4'-trimethylangelicin in DNA. These monoclonal antibodies have been characterized as to sensitivity and specificity using non-competitive and competitive enzyme-linked-immunosorbent assays (ELISA).

  3. Radiation damage in DNA

    International Nuclear Information System (INIS)

    Lafleur, V.

    1978-01-01

    A number of experiments are described with the purpose to obtain a better insight in the chemical nature and the biological significance of radiation-induced damage in DNA, with some emphasis on the significance of alkali-labile sites. It is shown that not only reactions of OH radicals but also of H radicals introduce breaks and other inactivating damage in single-standed phiX174 DNA. It is found that phosphate buffer is very suitable for the study of the reactions of H radicals with DNA, as the H 2 PO 4 - ions convert the hydrated electrons into H radicals. The hydrated electron, which does react with DNA, does not cause a detectable inactivation. (Auth.)

  4. Impact damage in aircraft composite sandwich panels

    Science.gov (United States)

    Mordasky, Matthew D.

    same geometry (19mm diameter) and surface finish. A peak absorbed energy for perforation of 34.5J was identied regardless of the projectile density. The effect of composite panel manufacturing methods on the impact damage and energy absorption of the panel was also investigated. Specifically, damage related to pre-cured facesheets is compared to the co-cured facesheets used throughout the study.

  5. Radiation damage of uranium

    International Nuclear Information System (INIS)

    Lazarevic, Dj.

    1966-11-01

    Study of radiation damage covered the following: Kinetics of electric resistance of uranium and uranium alloy with 1% of molybdenum dependent on the second phase and burnup rate; Study of gas precipitation and diffusion of bubbles by transmission electron microscopy; Numerical analysis of the influence of defects distribution and concentration on the rare gas precipitation in uranium; study of thermal sedimentation of uranium alloy with molybdenum; diffusion of rare gas in metal by gas chromatography method

  6. Nondestructive damage detection and evaluation technique for seismically damaged structures

    Science.gov (United States)

    Adachi, Yukio; Unjoh, Shigeki; Kondoh, Masuo; Ohsumi, Michio

    1999-02-01

    The development of quantitative damage detection and evaluation technique, and damage detection technique for invisible damages of structures are required according to the lessons from the 1995 Hyogo-ken Nanbu earthquake. In this study, two quantitative damage sensing techniques for highway bridge structures are proposed. One method is to measure the change of vibration characteristics of the bridge structure. According to the damage detection test for damaged bridge column by shaking table test, this method can successfully detect the vibration characteristic change caused by damage progress due to increment excitations. The other method is to use self-diagnosis intelligent materials. According to the reinforced concrete beam specimen test, the second method can detect the damage by rupture of intelligent sensors, such as optical fiber or carbon fiber reinforced plastic rod.

  7. Earthquake damage to underground facilities

    International Nuclear Information System (INIS)

    Pratt, H.R.; Stephenson, D.E.; Zandt, G.; Bouchon, M.; Hustrulid, W.A.

    1980-01-01

    In order to assess the seismic risk for an underground facility, a data base was established and analyzed to evaluate the potential for seismic disturbance. Substantial damage to underground facilities is usually the result of displacements primarily along pre-existing faults and fractures, or at the surface entrance to these facilities. Evidence of this comes from both earthquakes and large explosions. Therefore, the displacement due to earthquakes as a function of depth is important in the evaluation of the hazard to underground facilities. To evaluate potential displacements due to seismic effects of block motions along pre-existing or induced fractures, the displacement fields surrounding two types of faults were investigated. Analytical models were used to determine relative displacements of shafts and near-surface displacement of large rock masses. Numerical methods were used to determine the displacement fields associated with pure strike-slip and vertical normal faults. Results are presented as displacements for various fault lengths as a function of depth and distance. This provides input to determine potential displacements in terms of depth and distance for underground facilities, important for assessing potential sites and design parameters

  8. Sampling the potential energy surface of a DNA duplex damaged by a food carcinogen: Force field parameterization by ab initio quantum calculations and conformational searching using molecular mechanics computations

    Science.gov (United States)

    Wu, Xiangyang

    1999-07-01

    The heterocyclic amine 2-amino-3-methylimidazo (4, 5-f) quinoline (IQ) is one of a number of carcinogens found in barbecued meat and fish. It induces tumors in mammals and is probably involved in human carcinogenesis, because of great exposure to such food carcinogens. IQ is biochemically activated to a derivative which reacts with DNA to form a covalent adduct. This adduct may deform the DNA and consequently cause a mutation. which may initiate carcinogenesis. To understand this cancer initiating event, it is necessary to obtain atomic resolution structures of the damaged DNA. No such structures are available experimentally due to synthesis difficulties. Therefore, we employ extensive molecular mechanics and dynamics calculations for this purpose. The major IQ-DNA adduct in the specific DNA sequence d(5'G1G2C G3CCA3') - d(5'TGGCGCC3') with IQ modified at G3 is studied. The d(5'G1G2C G3CC3') sequence has recently been shown to be a hot-spot for mutations when IQ modification is at G3. Although this sequence is prone to -2 deletions via a ``slippage mechanism'' even when unmodified, a key question is why IQ increases the mutation frequency of the unmodified DNA by about 104 fold. Is there a structural feature imposed by IQ that is responsible? The molecular mechanics and dynamics program AMBER for nucleic acids with the latest force field was chosen for this work. This force field has been demonstrated to reproduce well the B-DNA structure. However, some parameters, the partial charges, bond lengths and angles, dihedral parameters of the modified residue, are not available in the AMBER database. We parameterized the force field using high level ab initio quantum calculations. We created 800 starting conformations which uniformly sampled in combination at 18° intervals three torsion angles that govern the IQ-DNA orientations, and energy minimized them. The most important structures are abnormal; the IQ damaged guanine is rotated out of its standard B

  9. Cavitation damage prediction for the JSNS mercury target vessel

    Energy Technology Data Exchange (ETDEWEB)

    Naoe, Takashi, E-mail: naoe.takashi@jaea.go.jp; Kogawa, Hiroyuki; Wakui, Takashi; Haga, Katsuhiro; Teshigawara, Makoto; Kinoshita, Hidetaka; Takada, Hiroshi; Futakawa, Masatoshi

    2016-01-15

    The liquid mercury target system for the Japan Spallation Neutron Source (JSNS) at the Materials and Life science experimental Facility (MLF) in the Japan Proton Accelerator Research Complex (J-PARC) is designed to produce pulsed neutrons. The mercury target vessel in this system, which is made of type 316L stainless steel, is damaged by pressure wave-induced cavitation due to proton beam bombardment. Currently, cavitation damage is considered to be the dominant factor influencing the service life of the target vessel rather than radiation damage. In this study, cavitation damage to the interior surface of the target vessel was predicted on the basis of accumulated damage data from off-beam and on-beam experiments. The predicted damage was compared with the damage observed in a used target vessel. Furthermore, the effect of injecting gas microbubbles on cavitation damage was predicted through the measurement of the acoustic vibration of the target vessel. It was shown that the predicted depth of cavitation damage is reasonably coincident with the observed results. Moreover, it was confirmed that the injection of gas microbubbles had an effect on cavitation damage.

  10. Uncertainty in urban flood damage assessment due to urban drainage modelling and depth-damage curve estimation.

    Science.gov (United States)

    Freni, G; La Loggia, G; Notaro, V

    2010-01-01

    Due to the increased occurrence of flooding events in urban areas, many procedures for flood damage quantification have been defined in recent decades. The lack of large databases in most cases is overcome by combining the output of urban drainage models and damage curves linking flooding to expected damage. The application of advanced hydraulic models as diagnostic, design and decision-making support tools has become a standard practice in hydraulic research and application. Flooding damage functions are usually evaluated by a priori estimation of potential damage (based on the value of exposed goods) or by interpolating real damage data (recorded during historical flooding events). Hydraulic models have undergone continuous advancements, pushed forward by increasing computer capacity. The details of the flooding propagation process on the surface and the details of the interconnections between underground and surface drainage systems have been studied extensively in recent years, resulting in progressively more reliable models. The same level of was advancement has not been reached with regard to damage curves, for which improvements are highly connected to data availability; this remains the main bottleneck in the expected flooding damage estimation. Such functions are usually affected by significant uncertainty intrinsically related to the collected data and to the simplified structure of the adopted functional relationships. The present paper aimed to evaluate this uncertainty by comparing the intrinsic uncertainty connected to the construction of the damage-depth function to the hydraulic model uncertainty. In this way, the paper sought to evaluate the role of hydraulic model detail level in the wider context of flood damage estimation. This paper demonstrated that the use of detailed hydraulic models might not be justified because of the higher computational cost and the significant uncertainty in damage estimation curves. This uncertainty occurs mainly

  11. Military Robotics and Collateral Damage

    National Research Council Canada - National Science Library

    Kott, Robert Douglass ;Alexander

    2004-01-01

    .... Such concepts raise important questions in terms of their impact on collateral damage. In a broader context, western warfare in general places a continuously growing emphasis on issues of collateral damage...

  12. Radiation damage in semiconductor detectors

    International Nuclear Information System (INIS)

    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

  13. Tokamak ARC damage

    International Nuclear Information System (INIS)

    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

  14. Fatigue Damage in Wood

    DEFF Research Database (Denmark)

    Clorius, Christian Odin; Pedersen, Martin Bo Uhre; Hoffmeyer, Preben

    1996-01-01

    An investigation of fatigue failure in wood subjected to load cycles in compression parallel to grain is presented. Fatigue failure is found to depend both on the total time under load and on the number of cycles.Recent accelerated fatigue research on wood is reviewed, and a discrepancy between...... to 10 Hz are used. The number of cycles to failure is found to be a poor measure of the fatigue performance of wood. Creep, maximum strain, stiffness and work are monitored throughout the fatigue tests. Accumulated creep is suggested identified with damage and a correlation between stiffness reduction...

  15. Contextualizing aquired brain damage

    DEFF Research Database (Denmark)

    Nielsen, Charlotte Marie Bisgaard

    2014-01-01

    Contextualizing aquired brain damage Traditional approaches study ’communicational problems’ often in a discourse of disabledness or deficitness. With an ontology of communcation as something unique and a presupposed uniqueness of each one of us, how could an integrational approach (Integrational...... for people with aquired brain injuries will be presented and comparatively discussed in a traditional versus an integrational perspective. Preliminary results and considerations on ”methods” and ”participation” from this study will be presented along with an overview of the project's empirical data....

  16. Severe fuel damage projects

    International Nuclear Information System (INIS)

    Sdouz, G.

    1987-10-01

    After the descriptions of the generation of a Severe Fuel Damage Accident in a LWR the hypothetical course of such an accident is explained. Then the most significant projects are described. At each project the experimental facility, the most important results and the concluding models and codes are discussed. The selection of the projects is concentrated on the German Projekt Nukleare Sicherheit (PNS), tests performed at the Idaho National Engineering Laboratory (INEL) and smaller projects in France and Great Britain. 25 refs., 26 figs. (Author)

  17. Tokamak ARC damage

    Energy Technology Data Exchange (ETDEWEB)

    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.

  18. Technical Note: Assessment of Impact Damage to Apple Fruits ...

    African Journals Online (AJOL)

    An impact damage assessment of fresh apple fruits was carried out to ascertain the effects of height and surfaces on bruise area and impact energy. Five different impact surfaces namely: Cardboard (E), wood (F), metal (G), plastic (H) and foam (I) were used for the experiment. The weighed fruits were dropped from different ...

  19. Damage free Ar ion plasma surface treatment on In{sub 0.53}Ga{sub 0.47}As-on-silicon metal-oxide-semiconductor device

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Donghyi; Shin, Seung Heon; Ahn, Jaehyun; Sonde, Sushant; Banerjee, Sanjay K. [Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Road, Austin, Texas 78758 (United States); Kwon, Hyuk-Min [SK Hynix, Icheon, 2091, Gyeongchung-daero, Bubal-eub, Icheon-si, Gyeonggi-do 136-1 (Korea, Republic of); Orzali, Tommaso; Kim, Tae-Woo, E-mail: twkim78@gmail.com [SEMATECH Inc., 257 Fuller Rd #2200, Albany, New York 12203 (United States); Kim, Dae-Hyun [Kyungpook National University, 80, Daehak-ro, Buk-gu, Daegu 702-701 (Korea, Republic of)

    2015-11-02

    In this paper, we investigated the effect of in-situ Ar ion plasma surface pre-treatment in order to improve the interface properties of In{sub 0.53}Ga{sub 0.47}As for high-κ top-gate oxide deposition. X-ray photoelectron spectroscopy (XPS) and metal-oxide-semiconductor capacitors (MOSCAPs) demonstrate that Ar ion treatment removes the native oxide on In{sub 0.53}Ga{sub 0.47}As. The XPS spectra of Ar treated In{sub 0.53}Ga{sub 0.47}As show a decrease in the AsO{sub x} and GaO{sub x} signal intensities, and the MOSCAPs show higher accumulation capacitance (C{sub acc}), along with reduced frequency dispersion. In addition, Ar treatment is found to suppress the interface trap density (D{sub it}), which thereby led to a reduction in the threshold voltage (V{sub th}) degradation during constant voltage stress and relaxation. These results outline the potential of surface treatment for III-V channel metal-oxide-semiconductor devices and application to non-planar device process.

  20. Ulnar nerve damage (image)

    Science.gov (United States)

    The ulnar nerve originates from the brachial plexus and travels down arm. The nerve is commonly injured at the elbow because of elbow fracture or dislocation. The ulnar nerve is near the surface of the body where ...

  1. Damage evaluation system for materials used in fossil thermal power plants

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, Hiroyuki [Science Univ. of Tokyo (Japan); Sakai, Shinsuke [Tokyo Univ. (Japan); Tomita, Akira [Japan Power Engineering and Inspection Corp., Tokyo (Japan); Koyama, Teruo [Babcock Hitachi K.K., Tokyo (Japan); Sakurai, Shigeo; Kawasaki, Yoshiya [Hitachi Ltd., Ibaraki (Japan)

    1998-11-01

    The summary of this research paper is as follows: The fundamental design of the damage evaluation system is carried out based on the basic concept. Prototype systems for boilers and turbines have been constructed: (a) Boiler: (I) Evaluation part: Outer surface of the primary pendant superheater tube; (II) Damage mode: Creep; (III) Damage evaluation method: Hardness measurement method; (b) Turbine: (I) Evaluation part: Inner surface at the center bore of high pressure turbine rotor; (II) Damage mode: Creep; (III) Damage evaluation method: Electric potential method. (orig./MM)

  2. Thoracic damage control surgery.

    Science.gov (United States)

    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.

  3. Hydrogen damage in stainless steel

    International Nuclear Information System (INIS)

    Caskey, G.R. Jr.

    1981-01-01

    Hydrogen damage has been studied in a wide variety of stainless steels. Both internal and external hydrogen damage were evaluated by ductility or J-integral under rising tensile loads and by fractography. Analysis of the data has emphasized the potential effects of strain-induced martensite on hydrogen damage. Strain-induced martensite was neither necessary nor sufficient for hydrogen damage in the alloys studied. Neither ductility loss nor fracture-mode change correlated generally with martensite formation. Alloy composition, particularly nickel and nitrogen contents, was the primary factor in resistance to hydrogen damage. Thermomechanical processing, however, could alter the degree of hydrogen damage in an alloy and was critical for optimizing resistance to hydrogen damage. 10 figures, 10 tables

  4. Numerical simulations for impact damage detection in composites using vibrothermography

    International Nuclear Information System (INIS)

    Pieczonka, L J; Uhl, T; Szwedo, M; Staszewski, W J; Aymerich, F

    2010-01-01

    Composite materials are widely used in many engineering applications due to their high strength-to-weight ratios. However, it is well known that composites are susceptible to impact damage. Detection of impact damage is an important issue in maintenance of composite structures. Various non-destructive image-based techniques have been developed for damage detection in composite materials. These include vibrothermography that detects surface temperature changes due to heating associated with frictional energy dissipation by damage. In the present paper numerical simulations are used to investigate heat generation in a composite plate with impact damage in order to support damage detection analysis with vibrothermography. Explicit finite elements are used to model ultrasonic wave propagation in the damaged plate. Simulated delamination and cracks induce frictional heating in the plate. Coupled thermo-mechanical simulations are performed in high frequencies using commercial LS-Dyna finite element code. Very good qualitative agreement between measurements and simulations has been obtained. The area of increased temperature corresponds very well with the damaged area in both experiments and simulations. Numerical model has to be further refined in order to quantitatively match the experiments. The main issues of concern are frictional and thermal properties of composites. The final goal of these research efforts is to predict damage detection sensitivity of vibrothermography in real engineering applications based on numerical models.

  5. Laser-Induced Damage Growth on Larger-Aperture Fused Silica Optical Components at 351 nm

    International Nuclear Information System (INIS)

    Wan-Qing, Huang; Wei, Han; Fang, Wang; Yong, Xiang; Fu-Quan, Li; Bin, Feng; Feng, Jing; Xiao-Feng, Wei; Wan-Guo, Zheng; Xiao-Min, Zhang

    2009-01-01

    Laser-induced damage is a key lifetime limiter for optics in high-power laser facility. Damage initiation and growth under 351 nm high-fluence laser irradiation are observed on larger-aperture fused silica optics. The input surface of one fused silica component is damaged most severely and an explanation is presented. Obscurations and the area of a scratch on it are found to grow exponentially with the shot number. The area of damage site grows linearly. Micrographs of damage sites support the micro-explosion damage model which could be used to qualitatively explain the phenomena

  6. Analysis of Boling's laser-damage morphology

    International Nuclear Information System (INIS)

    Sparks, M.S.

    1980-01-01

    Boling observed that his total-internal-reflection laser-damage sites in glass closely resembled the scattering cross section for small (ka << 1), perfectly conducting sphere and suggested that a very small plasma formed and grew to a larger size, still with ka << 1 satisfied. Even with ka = 1, for which the cross section is different from that observed, the scattered field still is too small to explain the damage in terms of constructive interference between the incident- and scattered fields. Furthermore, the characteristic shape of the scattering cross section that matches the damage patterns is for circular polarization or unpolarized light, in contrast to the experimental plane polarizations. Extending the ideas to include effects of the scattered field outside the glass, such as plasma formation, and to include the correct field (with interesting polarization, including longitudinal circuler polarization at certain distances from the surface) incident on the sphere may explain the experiments. Additional experiments and analysis would be useful to determine if the extended model is valid and to investigate related materials improvement, nondestructive testing, and the relation between laser damage, plasma initiation, and failure under stress, all initiated at small isolated spots

  7. Damage scenarios and an onboard support system for damaged ships

    Directory of Open Access Journals (Sweden)

    Choi Jin

    2014-06-01

    Full Text Available Although a safety assessment of damaged ships, which considers environmental conditions such as waves and wind, is important in both the design and operation phases of ships, in Korea, rules or guidelines to conduct such assessments are not yet developed. However, NATO and European maritime societies have developed guidelines for a safety assessment. Therefore, it is required to develop rules or guidelines for safety assessments such as the Naval Ship Code (NSC of NATO. Before the safety assessment of a damaged ship can be performed, the available damage scenarios must be developed and the safety assessment criteria must be established. In this paper, the parameters related to damage by accidents are identified and categorized when developing damage scenarios. The need for damage safety assessment criteria is discussed, and an example is presented. In addition, a concept and specifications for the DB-based supporting system, which is used in the operation phases, are proposed.

  8. Environmentally damaging electricity trade

    International Nuclear Information System (INIS)

    Billette de Villemeur, Etienne; Pineau, Pierre-Olivier

    2010-01-01

    Electricity trade across regions is often considered welfare enhancing. We show in this paper that this should be reconsidered if environmental externalities are taken into account. We consider two cases where trade is beneficial, before accounting for environmental damages: first, when two regions with the same technology display some demand heterogeneity; second when one region endowed with hydropower arbitrages with its 'thermal' neighbor. Our results show that under reasonable demand and supply elasticities, trade comes with an additional environmental cost. This calls for integrating environmental externalities into market reforms when redesigning the electricity sector. Two North American applications illustrate our results: trade between Pennsylvania and New York, and trade between hydro-rich Quebec and New York.

  9. Vasectomy and psychosexual damage.

    Science.gov (United States)

    Savage, P M

    1972-11-01

    The director of the Family Planning Project of the San Bernardino County (California) Health Department reviews the results of a questionnaire completed by 300 husbands and their wives 6 months to 1 year after vasectomy. The replies indicated psychosexual damage from vasectomy is virtually nonexistent. 100% of the males reported an enhanced or unchanged sense of masculinity. Vasectomy clinics have been conducted by the San Bernardino County Health Department since August 1970. More than 1000 vasectomies have been completed. Vasectomies are currently being performed at a rate of 12/week. Prevasectomy group counseling should inform couples of 1) the physiological mechanisms involved, 2) the situational nature of any psychologic changes, and 3) the probability of irreversibility of the procedure.

  10. Environmentally damaging electricity trade

    Energy Technology Data Exchange (ETDEWEB)

    Billette de Villemeur, Etienne [Toulouse School of Economics (IDEI and GREMAQ) (France); Pineau, Pierre-Olivier [HEC Montreal (Canada)

    2010-03-15

    Electricity trade across regions is often considered welfare enhancing. We show in this paper that this should be reconsidered if environmental externalities are taken into account. We consider two cases where trade is beneficial, before accounting for environmental damages: first, when two regions with the same technology display some demand heterogeneity; second when one region endowed with hydropower arbitrages with its ''thermal'' neighbor. Our results show that under reasonable demand and supply elasticities, trade comes with an additional environmental cost. This calls for integrating environmental externalities into market reforms when redesigning the electricity sector. Two North American applications illustrate our results: trade between Pennsylvania and New York, and trade between hydro-rich Quebec and New York. (author)

  11. Tactical Damage Control Resuscitation.

    Science.gov (United States)

    Fisher, Andrew D; Miles, Ethan A; Cap, Andrew P; Strandenes, Geir; Kane, Shawn F

    2015-08-01

    Recently the Committee on Tactical Combat Casualty Care changed the guidelines on fluid use in hemorrhagic shock. The current strategy for treating hemorrhagic shock is based on early use of components: Packed Red Blood Cells (PRBCs), Fresh Frozen Plasma (FFP) and platelets in a 1:1:1 ratio. We suggest that lack of components to mimic whole blood functionality favors the use of Fresh Whole Blood in managing hemorrhagic shock on the battlefield. We present a safe and practical approach for its use at the point of injury in the combat environment called Tactical Damage Control Resuscitation. We describe pre-deployment preparation, assessment of hemorrhagic shock, and collection and transfusion of fresh whole blood at the point of injury. By approaching shock with goal-directed therapy, it is possible to extend the period of survivability in combat casualties. Reprint & Copyright © 2015 Association of Military Surgeons of the U.S.

  12. Radiation damage in nonmetallic solids under dense electronic excitation

    International Nuclear Information System (INIS)

    Itoh, Noriaki; Tanimura, Katsumi; Nakai, Yasuo

    1992-01-01

    Basic processes of radiation damage of insulators by dense electronic excitation are reviewed. First it is pointed out that electronic excitation of nonmetallic solids produces the self-trapped excitons and defect-related metastable states having relatively long lifetimes, and that the excitation of these metastable states, produces stable defects. The effects of irradiation with heavy ions, including track registration, are surveyed on the basis of the microscopic studies. It is pointed out also that the excitation of the metastable states plays a role in laser-induced damage at relatively low fluences, while the laser damage has been reported to be governed by heating of free electrons produced by multiphoton excitation. Difference in the contributions of the excitation of metastable defects to laser-induced damage of surfaces, or laser ablation, and laser-induced bulk damage is stressed. (orig.)

  13. Mechanism of cavitation damage and structure of a cavitating eddy

    International Nuclear Information System (INIS)

    Efimov, A.V.; Vorob'ev, G.A.; Filenko, Yu.I.; Petrov, K.N.

    1976-01-01

    As a result of experimental studies of the structure of a cavitating eddy and the action of single cavitation bubbles on a solid surface the assumption of double nature of cavitation damage forces depending on its regimes was made. The first type of the damage forces is shock waves, appearing around collapsing spherical bubble, the second type is hydraulic impacts of microjets making a hole in a collapsing aspherical bubble. The outward appearance of single microdents differs from each other. The damage of the first type is accompanied by corrosion. The cavitation erosion intensity of the damage of the first type exceeds that of the damage of the second type by one order of magnitude. The values of the porosity of a cavitation eddy, the bubble concentration and the distance between them, the bubble distribution according to the size and the form for the initial cavitation stage are given from holographic investigations

  14. Implantation damage in silicon devices

    International Nuclear Information System (INIS)

    Nicholas, K.H.

    1977-01-01

    Ion implantation, is an attractive technique for producing doped layers in silicon devices but the implantation process involves disruption of the lattice and defects are formed, which can degrade device properties. Methods of minimizing such damage are discussed and direct comparisons made between implantation and diffusion techniques in terms of defects in the final devices and the electrical performance of the devices. Defects are produced in the silicon lattice during implantation but they are annealed to form secondary defects even at room temperature. The annealing can be at a low temperature ( 0 C) when migration of defects in silicon in generally small, or at high temperature when they can grow well beyond the implanted region. The defect structures can be complicated by impurity atoms knocked into the silicon from surface layers by the implantation. Defects can also be produced within layers on top of the silicon and these can be very important in device fabrication. In addition to affecting the electrical properties of the final device, defects produced during fabrication may influence the chemical properties of the materials. The use of these properties to improve devices are discussed as well as the degradation they can cause. (author)

  15. Multivariate pluvial flood damage models

    International Nuclear Information System (INIS)

    Van Ootegem, Luc; Verhofstadt, Elsy; Van Herck, Kristine; Creten, Tom

    2015-01-01

    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

  16. Multivariate pluvial flood damage models

    Energy Technology Data Exchange (ETDEWEB)

    Van Ootegem, Luc [HIVA — University of Louvain (Belgium); SHERPPA — Ghent University (Belgium); Verhofstadt, Elsy [SHERPPA — Ghent University (Belgium); Van Herck, Kristine; Creten, Tom [HIVA — University of Louvain (Belgium)

    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.

  17. Laser damage testing at LLL: an overview and an update

    International Nuclear Information System (INIS)

    Milam, D.; Lowdermilk, W.H.; Wirtenson, G.R.

    1978-01-01

    Damage thresholds for single layers of common coating materials such as MgF 2 , SiO 2 , ThF 4 , Al 2 O 3 , ZrO 2 , and TiO 2 are given. Laser-induced damage of coated and uncoated optically polished surfaces has been studied at LLL for laser pulsewidths between 0.17 ns and 3 ns. Two 1064 nm Nd lasers generated this range of pulsewidths. This report contains a review of the results

  18. Effect of machining damage on tensile properties of beryllium

    International Nuclear Information System (INIS)

    Hanafee, J.E.

    1976-01-01

    It is well established that damage introduced at the surface of beryllium during machining operations can lower its mechanical properties. Tensile tests were conducted to illustrate this on beryllium presently being used for parts in the W79 program and similar to the new powder-processed beryllium specified for production (tentative specification MEL 76-001319). The objective of this study is to quantitatively illuminate the importance of controlling machining damage in this particular grade of powder-processed beryllium

  19. Multi-scale fracture damage associated with underground chemical explosions

    Science.gov (United States)

    Swanson, E. M.; Sussman, A. J.; Wilson, J. E.; Townsend, M. J.; Prothro, L. B.; Gang, H. E.

    2018-05-01

    Understanding rock damage induced by explosions is critical for a number of applications including the monitoring and verification of underground nuclear explosions, mine safety issues, and modeling fluid flow through fractured rock. We use core observations, televiewer logs, and thin section observations to investigate fracture damage associated with two successive underground chemical explosions (SPE2 and SPE3) in granitic rock at both the mesoscale and microscale. We compare the frequency and orientations of core-scale fractures, and the frequency of microfractures, between a pre-experiment core and three post-experiment cores. Natural fault zones and explosion-induced fractures in the vicinity of the explosive source are readily apparent in recovered core and in thin sections. Damage from faults and explosions is not always apparent in fracture frequency plots from televiewer logs, although orientation data from these logs suggests explosion-induced fracturing may not align with the pre-existing fracture sets. Core-scale observations indicate the extent of explosion-induced damage is 10.0 m after SPE2 and 6.8 m after SPE3, despite both a similar size and location for both explosions. At the microscale, damage is observed to a range distance of 10.2 ± 0.9 m after SPE2, and 16.6 ± 0.9 and 11.2 ± 0.6 in two different cores collected after SPE3. Additional explosion-induced damage, interpreted to be the result of spalling, is readily apparent near the surface, but only in the microfracture data. This depth extent and intensity of damage in the near-surface region also increased after an additional explosion. This study highlights the importance of evaluating structural damage at multiple scales for a more complete characterization of the damage, and particularly shows the importance of microscale observations for identifying spallation-induced damage.

  20. Surface Water & Surface Drainage

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This data set contains boundaries for all surface water and surface drainage for the state of New Mexico. It is in a vector digital data structure digitized from a...

  1. Measurement of damage in systemic vasculitis: a comparison of the Vasculitis Damage Index with the Combined Damage Assessment Index

    DEFF Research Database (Denmark)

    Suppiah, Ravi; Flossman, Oliver; Mukhtyar, Chetan

    2011-01-01

    To compare the Vasculitis Damage Index (VDI) with the Combined Damage Assessment Index (CDA) as measures of damage from vasculitis.......To compare the Vasculitis Damage Index (VDI) with the Combined Damage Assessment Index (CDA) as measures of damage from vasculitis....

  2. Detection of Damage in Operating Wind Turbines by Signature Distances

    Directory of Open Access Journals (Sweden)

    James F. Manwell

    2013-01-01

    Full Text Available Wind turbines operate in the atmospheric boundary layer and are subject to complex random loading. This precludes using a deterministic response of healthy turbines as the baseline for identifying the effect of damage on the measured response of operating turbines. In the absence of such a deterministic response, the stochastic dynamic response of the tower to a shutdown maneuver is found to be affected distinctively by damage in contrast to wind. Such a dynamic response, however, cannot be established for the blades. As an alternative, the estimate of blade damage is sought through its effect on the third or fourth modal frequency, each found to be mostly unaffected by wind. To discern the effect of damage from the wind effect on these responses, a unified method of damage detection is introduced that accommodates different responses. In this method, the dynamic responses are transformed to surfaces via continuous wavelet transforms to accentuate the effect of wind or damage on the dynamic response. Regions of significant deviations between these surfaces are then isolated in their corresponding planes to capture the change signatures. The image distances between these change signatures are shown to produce consistent estimates of damage for both the tower and the blades in presence of varying wind field profiles.

  3. Electron damage in organic crystals

    International Nuclear Information System (INIS)

    Howitt, D.G.; Thomas, G.

    1977-01-01

    The effects of radiation damage in three crystalline organic materials (l-valine, cytosine, copper phthalocyanine) have been investigated by electron microscopy. The degradation of these materials has been found to be consistent with a gradual collapse of their crystal structures brought about by ionization damage to the comprising molecules. It is inferred that the crystallinity of these materials is destroyed by ionizing radiation because the damaged molecules cannot be incorporated into the framework of their original structures. (author)

  4. Thermography detection on the fatigue damage

    Science.gov (United States)

    Yang, Bing

    It has always been a great temptation in finding new methods to in-situ "watch" the material fatigue-damage processes so that in-time reparations will be possible, and failures or losses can be minimized to the maximum extent. Realizing that temperature patterns may serve as fingerprints for stress-strain behaviors of materials, a state-of-art infrared (IR) thermography camera has been used to "watch" the temperature evolutions of both crystalline and amorphous materials "cycle by cycle" during fatigue experiments in the current research. The two-dimensional (2D) thermography technique records the surface-temperature evolutions of materials. Since all plastic deformations are related to heat dissipations, thermography provides an innovative method to in-situ monitor the heat-evolution processes, including plastic-deformation, mechanical-damage, and phase-transformation characteristics. With the understanding of the temperature evolutions during fatigue, thermography could provide the direct information and evidence of the stress-strain distribution, crack initiation and propagation, shear-band growth, and plastic-zone evolution, which will open up wide applications in studying the structural integrity of engineering components in service. In the current research, theoretical models combining thermodynamics and heat-conduction theory have been developed. Key issues in fatigue, such as in-situ stress-strain states, cyclic softening and hardening observations, and fatigue-life predictions, have been resolved by simply monitoring the specimen-temperature variation during fatigue. Furthermore, in-situ visulizations as well as qualitative and quantitative analyses of fatigue-damage processes, such as Luders-band evolutions, crack propagation, plastic zones, and final fracture, have been performed by thermography. As a method requiring no special sample preparation or surface contact by sensors, thermography provides an innovative and convenient method to in-situ monitor

  5. Damage detection in concrete structures with smart piezoceramic transducers

    Science.gov (United States)

    Naidu, Akshay S. K.; Bhalla, Suresh

    2003-10-01

    Detection of damages and progressive deterioration in structures is a critical issue. Visual inspections are tedious and unreliable. Incipient damages are often not discernible by low frequency dynamic response and other NDE techniques. Smart piezoelectric ceramic (PZT) transducers are emerging as an effective alternative in health monitoring of structures. The electro-mechanical impedance method employs the self-actuating and sensing characteristics of the PZT, without having to use actuators and sensors separately. When excited by an ac source, the PZT transducers bonded to the host structure activates the higher modes of vibration locally. Changes in the admittance response of the transducer serves as an indicator of damage around the transducer. In this paper, the effectiveness of PZT transducers for characterizing damages in concrete, in terms of the damage extent and location, is experimentally examined. The root mean square deviation (RMSD) index, adopted to quantify the changes in the admittance signatures, correlates with the damage extent. The damages on the surface that is not mounted by the PZT are also discernible. An array of transducers proves effective in detecting the damaged zone. The progressive incipient crack can be detected much before it actually becomes visible to the naked eye.

  6. Radiation damage to histones

    International Nuclear Information System (INIS)

    Mee, L.K.; Adelstein, S.J.

    1985-01-01

    The damage to histones irradiated in isolation is being elaborated to aid the identification of the crosslinking sites in radiation-induced DNA-histone adducts. Histones are being examined by amino acid analysis to determine the destruction of residues and by polyacrylamide gel electrophoresis to delineate changes in conformation. For the slightly lysine-rich histone, H2A, a specific attack on selective residues has been established, the aromatic residues, tyrosine and phenylalanine, and the heterocyclic residue, histidine, being significantly destroyed. In addition, a significant increase in aspartic acid was found; this may represent a radiation product from scission of the ring in the histidine residues. The similarity of the effects on residues in nitrous oxide-saturated and nitrogen-saturated solutions suggests that OH . and e/sub aq//sup -/ are equally efficient and selective in their attack. On gel electrophoresis degradation of the histone H2A was found to be greatest for irradiations in nitrous oxide-saturated solutions, suggesting CH . is the most effective radical for producing changes in conformation; O/sub 2//sup -/ was essentially ineffective. Other histones are being examined for changes in amino acid composition, conformation, and for the formation of radiation products

  7. Shock Initiation of Damaged Explosives

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. [Scanning electron microscopy of heat-damaged bone tissue].

    Science.gov (United States)

    Harsanyl, L

    1977-02-01

    Parts of diaphyses of bones were exposed to high temperature of 200-1300 degrees C. Damage to the bone tissue caused by the heat was investigated. The scanning electron microscopic picture seems to be characteristic of the temperature applied. When the bones heated to the high temperature of 700 degrees C characteristic changes appear on the periostal surface, higher temperatura on the other hand causes damage to the compact bone tissue and can be observed on the fracture-surface. Author stresses the importance of this technique in the legal medicine and anthropology.

  9. High-Damage-Threshold Pinhole for Glass Fusion Laser Applications

    International Nuclear Information System (INIS)

    Kumit, N.A.; Letzring, S.A.; Johnson, R.P.

    1998-01-01

    We are investigating methods to fabricate high-damage-threshold spatial-filter pinholes that might not be susceptible to plasma closure for relatively high energies and long pulses. These are based on the observation that grazing-incidence reflection from glass can withstand in excess of 5 kJ/cm 2 (normal to the beam) without plasma formation. The high damage threshold results from both the cos q spreading of the energy across the surface and the reflection of a large fraction of the energy from the surface, thereby greatly reducing the field strength within the medium

  10. Fatigue damage of nuclear facilities

    International Nuclear Information System (INIS)

    2001-01-01

    The conference on the fatigue damage of nuclear facilities, organized by the SFEN (french society of nuclear energy), took place at Paris the 23. of november 2000. Eleven papers were presented, showing the state of the art and the research programs in the domain of the sizing rules, safety, installations damage, examination and maintenance. (A.L.B.)

  11. Grounding Damage to Conventional Vessels

    DEFF Research Database (Denmark)

    Lützen, Marie; Simonsen, Bo Cerup

    2003-01-01

    The present paper is concerned with rational design of conventional vessels with regard to bottom damage generated in grounding accidents. The aim of the work described here is to improve the design basis, primarily through analysis of new statistical data for grounding damage. The current regula...

  12. Structural Damage in Mexico City

    OpenAIRE

    Hall, John F.; Beck, James L.

    1986-01-01

    This paper describes the structural damage in Mexico City caused by the September 19, 1985 earthquake. Photographs which illustrate various features of structural behavior are included. One explanation is presented as to why buildings with fundamental periods of elastic vibration considerably below the predominant two‐second period of the ground motion were most vulnerable to damage.

  13. Damage control in vascular injury

    NARCIS (Netherlands)

    Leenen, L. P.H.

    2017-01-01

    The highest goal in damage control surgery is to stop the bleeding. Major injuries to the vessels therefore pose the major challenge in the damage control approach. Optimal care can be provided in combination with receiving and treatment rooms with CT, operative and endovascular capabilities. For

  14. Bilateral contact problem with adhesion and damage

    Directory of Open Access Journals (Sweden)

    Adel Aissaoui

    2014-05-01

    Full Text Available We study a mathematical problem describing the frictionless adhesive contact between a viscoelastic material with damage and a foundation. The adhesion process is modeled by a bonding field on the contact surface. The contact is bilateral and the tangential shear due to the bonding field is included. We establish a variational formulation for the problem and prove the existence and uniqueness of the solution. The existence of a unique weak solution for the problem is established using arguments of nonlinear evolution equations with monotone operators, a classical existence and uniqueness result for parabolic inequalities, and Banach's fixed point theorem.

  15. Damage growth in aerospace composites

    CERN Document Server

    2015-01-01

    This book presents novel methods for the simulation of damage evolution in aerospace composites that will assist in predicting damage onset and growth and thus foster less conservative designs which realize the promised economic benefits of composite materials. The presented integrated numerical/experimental methodologies are capable of taking into account the presence of damage and its evolution in composite structures from the early phases of the design (conceptual design) through to the detailed finite element method analysis and verification phase. The book is based on the GARTEUR Research Project AG-32, which ran from 2007 to 2012, and documents the main results of that project. In addition, the state of the art in European projects on damage evolution in composites is reviewed. While the high specific strength and stiffness of composite materials make them suitable for aerospace structures, their sensitivity to damage means that designing with composites is a challenging task. The new approaches describ...

  16. Steady State Shift Damage Localization

    DEFF Research Database (Denmark)

    Sekjær, Claus; Bull, Thomas; Markvart, Morten Kusk

    2017-01-01

    The steady state shift damage localization (S3DL) method localizes structural deterioration, manifested as either a mass or stiffness perturbation, by interrogating the damage-induced change in the steady state vibration response with damage patterns cast from a theoretical model. Damage is, thus...... the required accuracy when examining complex structures, an extensive amount of degrees of freedom (DOF) must often be utilized. Since the interrogation matrix for each damage pattern depends on the size of the system matrices constituting the FE-model, the computational time quickly becomes of first......-order importance. The present paper investigates two sub-structuring approaches, in which the idea is to employ Craig-Bampton super-elements to reduce the amount of interrogation distributions while still providing an acceptable localization resolution. The first approach operates on a strict super-element level...

  17. Radiation Damage in Scintillating Crystals

    CERN Document Server

    Zhu Ren Yuan

    1998-01-01

    Crystal Calorimetry in future high energy physics experiments faces a new challenge to maintain its precision in a hostile radiation environment. This paper discusses the effects of radiation damage in scintillating crystals, and concludes that the predominant radiation damage effect in crystal scintillators is the radiation induced absorption, or color center formation, not the loss of the scintillation light yield. The importance of maintaining crystal's light response uniformity and the feasibility to build a precision crystal calorimeter under radiation are elaborated. The mechanism of the radiation damage in scintillating crystals is also discussed. While the damage in alkali halides is found to be caused by the oxygen or hydroxyl contamination, it is the structure defects, such as oxygen vacancies, cause damage in oxides. Material analysis methods used to reach these conclusions are presented in details.

  18. Anisotropic creep damage in the framework of continuum damage mechanics

    International Nuclear Information System (INIS)

    Caboche, J.L.

    1983-01-01

    For some years, various works have shown the possibility of applying continuum mechanics to model the evolution of the damage variable, initially introduced by Kachanov. Of interest here are the complex problems posed by the anisotropy which affects both the elastic behaviour and the viscoplastic one, and also the rupture phenomenon. The main concepts of the Continuum Damage Mechanics are briefly reviewed together with some classical ways to introduce anisotropy of damage in the particular case of proportional loadings. Based on previous works, two generalizations are presented and discussed, which use different kinds of tensors to describe the anisotropy of creep damage: - The first one, by Murakami and Ohno introduces a second rank damage tensor and a net stress tensor through a net area definition. The effective stress-strain behaviour is then obtained by a fourth rank tensor. - The second theory, by the author, uses one effective stress tensor only, defined in terms of the macroscopic strain behaviour, through a fourth-order non-symmetrical damage tensor. The two theories are compared at several levels: difference and similarities are pointed out for the damage evolution during tensile creep as well as for anisotropy effects. The possibilities are discussed and compared on the basis of some existing experimental results, which leads to a partial validation of the two approaches. (orig.)

  19. DNA damage in neurodegenerative diseases

    Energy Technology Data Exchange (ETDEWEB)

    Coppedè, Fabio, E-mail: fabio.coppede@med.unipi.it; Migliore, Lucia, E-mail: lucia.migliore@med.unipi.it

    2015-06-15

    Highlights: • Oxidative DNA damage is one of the earliest detectable events in the neurodegenerative process. • The mitochondrial DNA is more vulnerable to oxidative attack than the nuclear DNA. • Cytogenetic damage has been largely documented in Alzheimer's disease patients. • The question of whether DNA damage is cause or consequence of neurodegeneration is still open. • Increasing evidence links DNA damage and repair with epigenetic phenomena. - Abstract: Following the observation of increased oxidative DNA damage in nuclear and mitochondrial DNA extracted from post-mortem brain regions of patients affected by neurodegenerative diseases, the last years of the previous century and the first decade of the present one have been largely dedicated to the search of markers of DNA damage in neuronal samples and peripheral tissues of patients in early, intermediate or late stages of neurodegeneration. Those studies allowed to demonstrate that oxidative DNA damage is one of the earliest detectable events in neurodegeneration, but also revealed cytogenetic damage in neurodegenerative conditions, such as for example a tendency towards chromosome 21 malsegregation in Alzheimer's disease. As it happens for many neurodegenerative risk factors the question of whether DNA damage is cause or consequence of the neurodegenerative process is still open, and probably both is true. The research interest in markers of oxidative stress was shifted, in recent years, towards the search of epigenetic biomarkers of neurodegenerative disorders, following the accumulating evidence of a substantial contribution of epigenetic mechanisms to learning, memory processes, behavioural disorders and neurodegeneration. Increasing evidence is however linking DNA damage and repair with epigenetic phenomena, thereby opening the way to a very attractive and timely research topic in neurodegenerative diseases. We will address those issues in the context of Alzheimer's disease

  20. DNA damage in neurodegenerative diseases

    International Nuclear Information System (INIS)

    Coppedè, Fabio; Migliore, Lucia

    2015-01-01

    Highlights: • Oxidative DNA damage is one of the earliest detectable events in the neurodegenerative process. • The mitochondrial DNA is more vulnerable to oxidative attack than the nuclear DNA. • Cytogenetic damage has been largely documented in Alzheimer's disease patients. • The question of whether DNA damage is cause or consequence of neurodegeneration is still open. • Increasing evidence links DNA damage and repair with epigenetic phenomena. - Abstract: Following the observation of increased oxidative DNA damage in nuclear and mitochondrial DNA extracted from post-mortem brain regions of patients affected by neurodegenerative diseases, the last years of the previous century and the first decade of the present one have been largely dedicated to the search of markers of DNA damage in neuronal samples and peripheral tissues of patients in early, intermediate or late stages of neurodegeneration. Those studies allowed to demonstrate that oxidative DNA damage is one of the earliest detectable events in neurodegeneration, but also revealed cytogenetic damage in neurodegenerative conditions, such as for example a tendency towards chromosome 21 malsegregation in Alzheimer's disease. As it happens for many neurodegenerative risk factors the question of whether DNA damage is cause or consequence of the neurodegenerative process is still open, and probably both is true. The research interest in markers of oxidative stress was shifted, in recent years, towards the search of epigenetic biomarkers of neurodegenerative disorders, following the accumulating evidence of a substantial contribution of epigenetic mechanisms to learning, memory processes, behavioural disorders and neurodegeneration. Increasing evidence is however linking DNA damage and repair with epigenetic phenomena, thereby opening the way to a very attractive and timely research topic in neurodegenerative diseases. We will address those issues in the context of Alzheimer's disease

  1. Experimental verification of a progressive damage model for composite laminates based on continuum damage mechanics. M.S. Thesis Final Report

    Science.gov (United States)

    Coats, Timothy William

    1994-01-01

    Progressive failure is a crucial concern when using laminated composites in structural design. Therefore the ability to model damage and predict the life of laminated composites is vital. The purpose of this research was to experimentally verify the application of the continuum damage model, a progressive failure theory utilizing continuum damage mechanics, to a toughened material system. Damage due to tension-tension fatigue was documented for the IM7/5260 composite laminates. Crack density and delamination surface area were used to calculate matrix cracking and delamination internal state variables, respectively, to predict stiffness loss. A damage dependent finite element code qualitatively predicted trends in transverse matrix cracking, axial splits and local stress-strain distributions for notched quasi-isotropic laminates. The predictions were similar to the experimental data and it was concluded that the continuum damage model provided a good prediction of stiffness loss while qualitatively predicting damage growth in notched laminates.

  2. Simulation of Anisotropic Rock Damage for Geologic Fracturing

    Science.gov (United States)

    Busetti, S.; Xu, H.; Arson, C. F.

    2014-12-01

    A continuum damage model for differential stress-induced anisotropic crack formation and stiffness degradation is used to study geologic fracturing in rocks. The finite element-based model solves for deformation in the quasi-linear elastic domain and determines the six component damage tensor at each deformation increment. The model permits an isotropic or anisotropic intact or pre-damaged reference state, and the elasticity tensor evolves depending on the stress path. The damage variable, similar to Oda's fabric tensor, grows when the surface energy dissipated by three-dimensional opened cracks exceeds a threshold defined at the appropriate scale of the representative elementary volume (REV). At the laboratory or wellbore scale (1000m) scales the damaged REV reflects early natural fracturing (background or tectonic fracturing) or shear strain localization (fault process zone, fault-tip damage, etc.). The numerical model was recently benchmarked against triaxial stress-strain data from laboratory rock mechanics tests. However, the utility of the model to predict geologic fabric such as natural fracturing in hydrocarbon reservoirs was not fully explored. To test the ability of the model to predict geological fracturing, finite element simulations (Abaqus) of common geologic scenarios with known fracture patterns (borehole pressurization, folding, faulting) are simulated and the modeled damage tensor is compared against physical fracture observations. Simulated damage anisotropy is similar to that derived using fractured rock-mass upscaling techniques for pre-determined fracture patterns. This suggests that if model parameters are constrained with local data (e.g., lab, wellbore, or reservoir domain), forward modeling could be used to predict mechanical fabric at the relevant REV scale. This reference fabric also can be used as the starting material property to pre-condition subsequent deformation or fluid flow. Continuing efforts are to expand the present damage

  3. Lightning Damage to Wind Turbine Blades From Wind Farms in the U.S

    DEFF Research Database (Denmark)

    Candela Garolera, Anna; Madsen, Søren Find; Nissim, Maya

    2016-01-01

    , laminate structure, and lightning protection systems. The statistics consist of the distribution of lightning damage along the blade and classify the damage by severity. In addition, the frequency of lightning damage to more than one blade of a wind turbine after a thunderstorm is assessed. The results......This paper presents statistical data about lightning damage on wind turbine blades reported at different wind farms in the U.S. The analysis is based on 304 cases of damage due to direct lightning attachment on the blade surface. This study includes a large variety of blades with different lengths...

  4. Forecasting Frost Damage: Follow the Water

    Science.gov (United States)

    Rempel, A. W.

    2015-12-01

    Frost damage takes place when the pressure exerted against pore walls exceeds the cohesive strength of water-infiltrated rock and causes cracks to extend. Elegant theoretical treatments supported by meticulous field and laboratory observations have combined to unravel the basic mechanical and thermodynamic controls in idealized systems. Frost damage is most vigorous when conditions are cold enough that the net pressure exerted against the pore walls can cause crack extension, yet warm enough to enable the flow that supplies further ice growth in the newly opened space. This insight is applied here to develop practical geomorphic process laws for the effects of frost damage at the larger scales that are relevant for describing the evolution of landscapes. To this end, a direct connection is made between the intensity of frost damage and the porosity increase that results from gradients in water flux under conditions that are cold enough for ice-rock interactions to propagate cracks. This implies that the annual temperature variation at the ground surface can be combined with considerations of heat and mass transport to derive rigorous forecasts of the potential for frost damage that are tied to the increases in water mass that accompany solidification in porous rock. As an example, the image shows the depth-integrated porosity change λ promoted by crack growth at temperatures colder than -ΔTc over an annual cycle for different choices of mean annual temperature MAT and surface amplitude A (assuming a thermal diffusivity of 1 mm2/s and a power-law relationship between permeability and undercooling with exponent α=4, such that a base value of 10-14m2 is reached at a reference undercooling of 0.1 ºC). The abrupt onset in cracking once MAT decreases below a threshold is produced by the requirement that undercooling surpass ΔTc in order to generate sufficient pressures to propagate cracks. The eventual reduction and gradual tail in λ at colder MAT is produced by

  5. Seismic damage identification for steel structures using distributed fiber optics.

    Science.gov (United States)

    Hou, Shuang; Cai, C S; Ou, Jinping

    2009-08-01

    A distributed fiber optic monitoring methodology based on optic time domain reflectometry technology is developed for seismic damage identification of steel structures. Epoxy with a strength closely associated to a specified structure damage state is used for bonding zigzagged configured optic fibers on the surfaces of the structure. Sensing the local deformation of the structure, the epoxy modulates the signal change within the optic fiber in response to the damage state of the structure. A monotonic loading test is conducted on a steel specimen installed with the proposed sensing system using selected epoxy that will crack at the designated strain level, which indicates the damage of the steel structure. Then, using the selected epoxy, a varying degree of cyclic loading amplitudes, which is associated with different damage states, is applied on a second specimen. The test results show that the specimen's damage can be identified by the optic sensors, and its maximum local deformation can be recorded by the sensing system; moreover, the damage evolution can also be identified.

  6. Pest damage assessment in fruits and vegetables using thermal imaging

    Science.gov (United States)

    Vadakkapattu Canthadai, Badrinath; Muthuraju, M. Esakki; Pachava, Vengalrao; Sengupta, Dipankar

    2015-05-01

    In some fruits and vegetables, it is difficult to visually identify the ones which are pest infested. This particular aspect is important for quarantine and commercial operations. In this article, we propose to present the results of a novel technique using thermal imaging camera to detect the nature and extent of pest damage in fruits and vegetables, besides indicating the level of maturity and often the presence of the pest. Our key idea relies on the fact that there is a difference in the heat capacity of normal and damaged ones and also observed the change in surface temperature over time that is slower in damaged ones. This paper presents the concept of non-destructive evaluation using thermal imaging technique for identifying pest damage levels of fruits and vegetables based on investigations carried out on random samples collected from a local market.

  7. Mechanisms of subsidence for induced damage and techniques for analysis

    International Nuclear Information System (INIS)

    Drumm, E.C.; Bennett, R.M.; Kane, W.F.

    1988-01-01

    Structural damage due to mining induced subsidence is a function of the nature of the structure and its position on the subsidence profile. A point on the profile may be in the tensile zone, the compressive zone, or the no-deformation zone at the bottom of the profile. Damage to structures in the tension zone is primarily due to a reduction of support during vertical displacement of the ground surface, and to shear stresses between the soil and structure resulting from horizontal displacements. The damage mechanisms due to tension can be investigated effectively using a two-dimensional plane stress analysis. Structures in the compression zone are subjected to positive moments in the footing and large compressive horizontal stresses in the foundation walls. A plane strain analysis of the foundation wall is utilized to examine compression zone damage mechanisms. The structural aspects affecting each mechanism are identified and potential mitigation techniques are summarized

  8. Study on Damage Mechanism of Ductile Cast Iron Cooling Stave

    Science.gov (United States)

    Wang, Cui; Zhang, Jianliang; Zuo, Haibin; Dai, Bing

    The damage mechanism of ductile cast iron cooling stave applied to No.4 blast furnace of Guofeng steel was analyzed through damage investigation in details, the damage causes: high-temperature gas flow erosion, wear of burden, high-temperature ablation, carburizing damage, improper operation on blast furnace, etc. were given out both in macroscopic and microscopic views. It can be obtained from metallographic diagrams that the diameter of graphite nodules increases, the number per unit area reduces, and roundness declines, successively, from cold to hot surface, which are not conducive to stave longevity. In summary, the material for staves manufacture should be better in comprehensive mechanical properties to prolong the service life, thus making blast furnace long campaign.

  9. Surface damage-caused inelastic relaxation in solids

    International Nuclear Information System (INIS)

    Darinskij, B.M.; Izmajlov, N.V.; Loginov, V.A.; Mitrokhin, V.I.; Yaroslavtsev, N.P.

    1987-01-01

    Internal friction (IF) in solids having different structure: crystalline- Si, Ga, P, GaAs, InP, InAs, CdTe, LiNbO 3 ; amorphous-crystalline-devitrified glass ST-50; amorphous- quartz glass, has been studied. IF peak was observed in each of the specimens at the frequency of bed oscillations equal to 8-30 kHz in the -70- -50 deg C temperature range. Its parameters (activation energy, frequency factor, etc.) for each of the materials are presented. Strong dependence of the peak height on the amplitude of deformation is ascertained, the annealing temperature is determined

  10. Damage of metal surfaces by a hot, dense deuterium plasma

    International Nuclear Information System (INIS)

    Panayotou, N.F.

    1978-01-01

    The effect of differences in alloy chemistry and systematic changes in microstructural interface density on the occurrence of unipolar arcing was studied. The effect of thermionic emission is examined by comparing the refractory metals W, Nb, and Nb-751 alloy to the non-refractory stainless steels, AISI 304, 316 and Nimonic PE-16. The effect of alloying additions is examined by comparing Mo containing 316 and Mo free 304 stainless steels as well as Zr containing Nb-751 and Zr free Nb. The effect of interface density is examined by systematically varying the density of microstructural interfaces in AISI 4130, a ferritic steel. Although most of the metals and alloys studied are candidate fusion reactor materials, 4130 was chosen on the basis of our ability to modify the density of microstructural interfaces in the material by heat treatment. The results are discussed with respect to available unipolar arcing theory. The significance of the work, in terms of actual power reactors is assessed and the need for further work defined

  11. Mitigation of wear damage by laser surface alloying technique

    CSIR Research Space (South Africa)

    Adebiyi, ID

    2016-04-01

    Full Text Available stream_source_info Adebiyi_2016.pdf.txt stream_content_type text/plain stream_size 1481 Content-Encoding UTF-8 stream_name Adebiyi_2016.pdf.txt Content-Type text/plain; charset=UTF-8 Advanced Manufacturing Techniques...

  12. Clinical light damage to the eye

    International Nuclear Information System (INIS)

    Miller, D.

    1987-01-01

    This book contains four sections: The Nature of Light and of Light Damage to Biological Tissues; Light Damage to the Eye; Protecting the Eye from Light Damage; and Overview of Light Damage to the Eye. Some of the paper titles are: Ultraviolet-Absorbing Intraocular Lens Implants; Phototoxic Changes in the Retina; Light Damage to the Lens; and Radiation, Light, and Sight

  13. Damage analysis. Product improvement through damage analysis; Schadensanalyse. Produktverbesserung durch Schadensanalyse

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    Within the 37th VDI annual meeting from 19th to 20th May, 2011 in Wuerzburg (Federal Republic of Germany) the following lectures and posters were presented: (1) Malpractice of material processing and heat processing of large gear wheels (P. Sommer); (2) Damages by faulty heat treatment - Case studies: Glow testing at a heat exchanger and wheel breakage of a high-strength screw connection (A. Thomas); (3) Crack formation in pole end plates of high-performance generators of a pumped-storage power plant - Causes and possibilities of remedy (J. Kinder); (4) Grind burn inspection for damage prevention at wind turbine gearboxes - Use of different processes for the investigation of peripheral-zone properties of case-hardened components (T. Griggel); (5) Damage inspection in coal mines using products from the degradation process as an example - damage - inspection - solution: This is the working method of the certification body (C. Kleine-Hegermann); (6) Damages at the sealing rings - Causes of the failure at radial shaft rings (K. Marchetti); (7) Thermal analyses at faulty plastic components (O. Jacobs); (8) Application of the micro computer tomography at damages of fibre-reinforced materials (H. Dinnebier); (9) The significance of 'material defects' from the view of lay people, lawyers and engineers - 'Material defect' in the literature, set of rules and expert opinion (C. Klinger); (10) Material defects from a legal view (P. Henseler); (11) Significance of material defects from the view of an engineering insurer (C. Harden); (12) Wear analyses by means of RNT and non-destructive surface analytics (K. Poehlmann); (13) Damages by means of non-metallic inclusions using ICE 3 as an example - Significance and localisation of single non-metallic inclusions in large components (D. Bettge); (14) Cathodic corrosion protection of pipeline steels (H.-G. Schoeneich); (15) Non-destructive and destructive investigations when assessing damages of corrosion at a

  14. Radiation damage in components

    International Nuclear Information System (INIS)

    Takano, Tomehachi

    1977-01-01

    The performance change of typical capacitors and resistors in electronic components by Co-60 γ-irradiation from the 1320 Ci source was examined in the range of 10 5 to 10 8 R. Specifically, the characteristic change during irradiation and the recovery after irradiation were continuously observed. The capacity change is +2.4% at maximum in ceramic and metallized paper capacitors, and -2.4% at maximum in mylar and paper capacitors. It is also +-0.4% at maximum in mica and polystyrene capacitors. Some of these capacitors showed the recovery of the capacity change, but the others did not. Dielectric loss varied by 15% at larger dose in some capacitors, and the recovery was not observed. While, the insulation resistance of the resistors of 10 15 Ω or more lowered to 10 13 Ω or less after 10 to 30 sec. irradiation, but recovered soon nearly to the initial values after irradiation was interrupted. The resistance change of carbon film resistors is about 0.2 to 2%, and recovered to the initial values in 100 hours after irradiation. The resistance change of composition resistors is large over the range of -13 to +35%, besides, no sign of recovery was seen. In carbon film resistors, the surface insulated type indicated far better results which are assumed to be caused by the selection of element materials and the forming of coating materials. (Wakatsuki, Y.)

  15. BDS thin film damage competition

    Science.gov (United States)

    Stolz, Christopher J.; Thomas, Michael D.; Griffin, Andrew J.

    2008-10-01

    A laser damage competition was held at the 2008 Boulder Damage Symposium in order to determine the current status of thin film laser resistance within the private, academic, and government sectors. This damage competition allows a direct comparison of the current state-of-the-art of high laser resistance coatings since they are all tested using the same damage test setup and the same protocol. A normal incidence high reflector multilayer coating was selected at a wavelength of 1064 nm. The substrates were provided by the submitters. A double blind test assured sample and submitter anonymity so only a summary of the results are presented here. In addition to the laser resistance results, details of deposition processes, coating materials, and layer count will also be shared.

  16. Probabilistic Fatigue Damage Program (FATIG)

    Science.gov (United States)

    Michalopoulos, Constantine

    2012-01-01

    FATIG computes fatigue damage/fatigue life using the stress rms (root mean square) value, the total number of cycles, and S-N curve parameters. The damage is computed by the following methods: (a) traditional method using Miner s rule with stress cycles determined from a Rayleigh distribution up to 3*sigma; and (b) classical fatigue damage formula involving the Gamma function, which is derived from the integral version of Miner's rule. The integration is carried out over all stress amplitudes. This software solves the problem of probabilistic fatigue damage using the integral form of the Palmgren-Miner rule. The software computes fatigue life using an approach involving all stress amplitudes, up to N*sigma, as specified by the user. It can be used in the design of structural components subjected to random dynamic loading, or by any stress analyst with minimal training for fatigue life estimates of structural components.

  17. Kava Linked to Liver Damage

    Science.gov (United States)

    ... of these countries to remove kava from the market. Although liver damage appears to be rare, the ... are marketed to men, women, children, and the elderly. Advice to Consumers Safety is a concern for ...

  18. Civil Liability for Environmental Damages

    Directory of Open Access Journals (Sweden)

    Daniela Ciochină

    2012-05-01

    Full Text Available We debated in this article the civil liability for environmental damages as stipulated in ourlegislation with reference to Community law. The theory of legal liability in environmental law is basedon the duty of all citizens to respect and protect the environment. Considering the importance ofenvironment in which we live, the liability for environmental damages is treated by the Constitution as aprinciple and a fundamental obligation. Many human activities cause environmental damages and, in linewith the principle of sustainable development, they should be avoided. However, when this is notpossible, they must be regulated (by criminal or administrative law in order to limit their adverse effectsand, according to the polluter pays principle, to internalize in advance their externalities (through taxes,insurances or other forms of financial security products. Communication aims to analyze these issues andlegal regulations dealing with the issue of liability for environmental damage.

  19. Corneal Damage from Infrared Radiation

    National Research Council Canada - National Science Library

    McCally, Russell

    2000-01-01

    ...) laser radiation at 10.6 (micrometer) and Tm: YAG laser radiation at 2.02 (micrometer). Retinal damage from sources with rectangular irradiance distributions was also modeled. Thresholds for CO(2...

  20. Radiation Damage and Dimensional Changes

    International Nuclear Information System (INIS)

    El-Barbary, A.A.; Lebda, H.I.; Kamel, M.A.

    2009-01-01

    The dimensional changes have been modeled in order to be accommodated in the reactor design. This study has major implications for the interpretation of damage in carbon based nuclear fission and fusion plant materials. Radiation damage of graphite leads to self-interstitials and vacancies defects. The aggregation of these defects causes dimensional changes. Vacancies aggregate into lines and disks which heal and contract the basal planes. Interstitials aggregate into interlayer disks which expand the dimension

  1. Apportioning liability for transborder damage

    International Nuclear Information System (INIS)

    Krause-Ablass, W.D.

    1988-01-01

    The author analyses the different legal systems applicable to transfrontier nuclear damage. Using examples, he describes the mechanisms enabling a victim of such damage to identify the competent court and the relevant law, according to whether the provisions of the Paris or the Vienna Convention come into play or whether the rules of private international law, incorporated in the various national laws are applicable (NEA) [fr

  2. Damage Atlas for Photographic materials

    Directory of Open Access Journals (Sweden)

    Kristel Van Camp

    2010-11-01

    Full Text Available La conservation des documents photographiques peut nécessiter des interventions préventives ou curatives. Ce choix est guidé par leur état de conservation. Une meilleure connaissance des détériorations est donc cruciale. Le répertoire présenté ici essaie de les classifier selon des caractéristiques spécifiques et leur niveau de gravité. Les différents types de dégradation sont illustrés et décrits avec une terminologie précise. L’auteur propose en regard de ceux-ci l’intervention qui semble la plus appropriée. Ce répertoire s’adresse à toutes les personnes concernées par la photographie, qu’ils soient dans le milieu de la conservation ou dans le domaine artistique, dans les musées ou dans les archives. In order to rescue a damaged photographic object, preventive or conservative actions are needed. Knowing the specific characteristics of different types of damage is crucial. A damage atlas can provide these characteristics. With this atlas the damage can be recognised and appropriate actions can be taken. This damage atlas offers a first attempt to such a characterisation in the field of photography. The damage atlas contains images and the necessary information about damage on photographic material. The atlas with special annotations about the terminology and the grade of the damage is meant for everybody who works with photographic material, as well in museums as in archives.

  3. Damage Localization and Quantification of Earthquake Excited RC-Frames

    DEFF Research Database (Denmark)

    Skjærbæk, P.S.; Nielsen, Søren R.K.; Kirkegaard, Poul Henning

    In the paper a recently proposed method for damage localization and quantification of RC-structures from response measurements is tested on experimental data. The method investigated requires at least one response measurement along the structure and the ground surface acceleration. Further, the t...

  4. Label-free electrochemical detection of singlet oxygen protein damage

    Czech Academy of Sciences Publication Activity Database

    Vargová, Veronika; Gimenez, R.E.; Černocká, Hana; Trujillo, D.C.; Tulli, F.; Zanini, V.I.P.; Paleček, Emil; Borsarelli, C.D.; Ostatná, Veronika

    2016-01-01

    Roč. 187, JAN 2016 (2016), s. 662-669 ISSN 0013-4686 R&D Projects: GA ČR GA13-00956S Institutional support: RVO:68081707 Keywords : singlet oxygen protein damage * surface-attached protein stability * mercury and carbon electrodes Subject RIV: BO - Biophysics Impact factor: 4.798, year: 2016

  5. RENAL DAMAGE WITH MALIGNANT NEOPLASMS

    Directory of Open Access Journals (Sweden)

    I. B. Kolina

    2015-01-01

    Full Text Available The relationship between renal damage and malignant neoplasms is one of the most actual problems of the medicine of internal diseases. Very often, exactly availability of renal damage determines the forecast of cancer patients. The range of renal pathologies associated with tumors is unusually wide: from the mechanical effect of the tumor or metastases on the kidneys and/or the urinary tract and paraneoplastic manifestations in the form of nephritis or amyloidosis to nephropathies induced with drugs or tumor lysis, etc. Thrombotic complications that develop as a result of exposure to tumor effects, side effects of certain drugs or irradiation also play an important role in the development of the kidney damage. The most frequent variants of renal damage observed in the practice of medical internists (therapists, urologists, surgeons, etc., as well as methods of diagnosis and treatment approaches are described in the article. Timely and successful prevention and treatment of tumor-associated nephropathies give hope for retaining renal functions, therefore, a higher life standard after completion of anti-tumor therapy. Even a shortterm episode of acute renal damage suffered by a cancer patient must be accompanied with relevant examination and treatment. In the caseof transformation of acute renal damage into the chronic kidney disease, such patients need systematic and weighted renoprotective therapy and correct dosing of nephrotoxic drugs.

  6. Advanced materials and protective coatings in aero-engines application

    OpenAIRE

    M. Hetmańczyk; L. Swadźba; B. Mendala

    2007-01-01

    Purpose: The following article demonstrates the characteristics of the materials applied as parts of aircraft engine turbines and the stationary gas turbines. The principal technologies for manufacturing the heat resistant coatings and the erosion and corrosion resistant coatings were characterized. Sample applications for the aforementioned coatings are presented: on turbine blades, compressor blades and on parts of combustion chambers of aircraft engines.Design/methodology/approach: The nic...

  7. Robust Nonlinear Control of Stall and Flutter in Aeroengines

    National Research Council Canada - National Science Library

    Murray, Richard

    2001-01-01

    ... (bleed valves and air injection). The goal of the third activity, begun after the initial student supported by the grant left Caltech, was to develop modeling and control approaches for complex, physical systems, including control...

  8. Design Of Cooling Configuration For Military Aeroengine V-Gutter

    Directory of Open Access Journals (Sweden)

    Batchu Suresh

    2017-07-01

    Full Text Available Military aircraft engines employ afterburner system for increasing the thrust required during combat and take-off flight conditions. V-gutter is employed for stabilisation of the flame during reheat. For fifth generation aero engine the gas temperature at the start of the afterburner is be-yond the allowable material limits of the V-gutter so it is required to cool the V-gutter to obtain acceptable creep life. The design of cooling configuration for the given source pressure is worked out for different rib configurations to obtain the allowable metal temperature with minimum coolant mass flow.1D network analysis is used to estimate the cooling mass flow and metal temperature for design flight condition. CFD analysis is carried out for four cooling configurations with different rib orientations. Out of four configurations one configuration is selected for the best cooling configuration.

  9. CEREBRAL CORTEX DAMAGE INDUCED BY ACUTE ORAL ...

    African Journals Online (AJOL)

    2018-02-28

    Feb 28, 2018 ... This study examines alcohol-induced cerebral cortex damage and the association with oxidative ... alcohol has profound effects on the function ... Chronic use of ..... Alcohol induced brain damage and liver damage in young.

  10. Growth of Laser Initiated Damage in Fused Silica at 527 nm

    International Nuclear Information System (INIS)

    Norton, M A; Donohue, E E; Hollingsworth, W G; McElroy, J N; Hackel, R P

    2003-01-01

    The effective lifetime of optics is limited by both laser-induced damage and the subsequent growth of laser initiated damage sites. We have measured the growth rate of laser-induced damage in fused silica in both air and vacuum at 527 nm. For damage on the exit surface, the data shows exponential growth in the lateral size of the damage site with shot number. The exponential growth coefficient depends linearly on the laser fluence. The behavior at the fluence threshold for growth is contrasted to that observed at 351 nm. The growth rate was not significantly affected by either the wavelength of the initiating fluence or the presence of 10 torr of air as compared to vacuum. When the damage is located on the input surface, it has both a higher threshold for growth and does not grow exponentially

  11. Glaucomatous damage of the macula.

    Science.gov (United States)

    Hood, Donald C; Raza, Ali S; de Moraes, Carlos Gustavo V; Liebmann, Jeffrey M; Ritch, Robert

    2013-01-01

    There is a growing body of evidence that early glaucomatous damage involves the macula. The anatomical basis of this damage can be studied using frequency domain optical coherence tomography (fdOCT), by which the local thickness of the retinal nerve fiber layer (RNFL) and local retinal ganglion cell plus inner plexiform (RGC+) layer can be measured. Based upon averaged fdOCT results from healthy controls and patients, we show that: 1. For healthy controls, the average RGC+ layer thickness closely matches human histological data; 2. For glaucoma patients and suspects, the average RGC+ layer shows greater glaucomatous thinning in the inferior retina (superior visual field (VF)); and 3. The central test points of the 6° VF grid (24-2 test pattern) miss the region of greatest RGC+ thinning. Based upon fdOCT results from individual patients, we have learned that: 1. Local RGC+ loss is associated with local VF sensitivity loss as long as the displacement of RGCs from the foveal center is taken into consideration; and 2. Macular damage is typically arcuate in nature and often associated with local RNFL thinning in a narrow region of the disc, which we call the macular vulnerability zone (MVZ). According to our schematic model of macular damage, most of the inferior region of the macula projects to the MVZ, which is located largely in the inferior quadrant of the disc, a region that is particularly susceptible to glaucomatous damage. A small (cecocentral) region of the inferior macula, and all of the superior macula (inferior VF), project to the temporal quadrant, a region that is less susceptible to damage. The overall message is clear; clinicians need to be aware that glaucomatous damage to the macula is common, can occur early in the disease, and can be missed and/or underestimated with standard VF tests that use a 6° grid, such as the 24-2 VF test. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Automatic detection and classification of damage zone(s) for incorporating in digital image correlation technique

    Science.gov (United States)

    Bhattacharjee, Sudipta; Deb, Debasis

    2016-07-01

    Digital image correlation (DIC) is a technique developed for monitoring surface deformation/displacement of an object under loading conditions. This method is further refined to make it capable of handling discontinuities on the surface of the sample. A damage zone is referred to a surface area fractured and opened in due course of loading. In this study, an algorithm is presented to automatically detect multiple damage zones in deformed image. The algorithm identifies the pixels located inside these zones and eliminate them from FEM-DIC processes. The proposed algorithm is successfully implemented on several damaged samples to estimate displacement fields of an object under loading conditions. This study shows that displacement fields represent the damage conditions reasonably well as compared to regular FEM-DIC technique without considering the damage zones.

  13. Fuel containment and damage tolerance for large composite primary aircraft structures. Phase 1: Testing

    Science.gov (United States)

    Sandifer, J. P.

    1983-01-01

    Technical problems associated with fuel containment and damage tolerance of composite material wings for transport aircraft were identified. The major tasks are the following: (1) the preliminary design of damage tolerant wing surface using composite materials; (2) the evaluation of fuel sealing and lightning protection methods for a composite material wing; and (3) an experimental investigation of the damage tolerant characteristics of toughened resin graphite/epoxy materials. The test results, the test techniques, and the test data are presented.

  14. Application of RMS for damage detection by guided elastic waves

    Energy Technology Data Exchange (ETDEWEB)

    Radzienski, M; Dolinski, L; Krawczuk, M [Gdansk University of Technology, Faculty of Electrical and Control Engineering, Narutowicza 11/12, 80-952 Gdansk (Poland); Zak, A; Ostachowicz, W, E-mail: Maciej.Radzienski@gmail.com [Szewalski Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Fiszera 14, 80-952 Gdansk (Poland)

    2011-07-19

    This paper presents certain results of an experimental study related with a damage detection in structural elements based on deviations in guided elastic wave propagation patterns. In order to excite guided elastic waves within specimens tested piezoelectric transducers have been applied. As excitation signals 5 sine cycles modulated by Hanning window have been used. Propagation of guided elastic waves has been monitored by a scanning Doppler laser vibrometer. The time signals recorded during measurement have been utilised to calculate the values of RMS. It has turned out that the values of RMS differed significantly in damaged areas from the values calculated for the healthy ones. In this way it has become possible to pinpoint precisely the locations of damage over the entire measured surface. All experimental investigations have been carried out for thin aluminium or composite plates. Damage has been simulated by a small additional mass attached on the plate surface or by a narrow notch cut. It has been shown that proposed method allows one to localise damage of various shapes and sizes within structural elements over the whole area under investigation.

  15. Application of RMS for damage detection by guided elastic waves

    Science.gov (United States)

    Radzieński, M.; Doliński, Ł.; Krawczuk, M.; dot Zak, A.; Ostachowicz, W.

    2011-07-01

    This paper presents certain results of an experimental study related with a damage detection in structural elements based on deviations in guided elastic wave propagation patterns. In order to excite guided elastic waves within specimens tested piezoelectric transducers have been applied. As excitation signals 5 sine cycles modulated by Hanning window have been used. Propagation of guided elastic waves has been monitored by a scanning Doppler laser vibrometer. The time signals recorded during measurement have been utilised to calculate the values of RMS. It has turned out that the values of RMS differed significantly in damaged areas from the values calculated for the healthy ones. In this way it has become possible to pinpoint precisely the locations of damage over the entire measured surface. All experimental investigations have been carried out for thin aluminium or composite plates. Damage has been simulated by a small additional mass attached on the plate surface or by a narrow notch cut. It has been shown that proposed method allows one to localise damage of various shapes and sizes within structural elements over the whole area under investigation.

  16. DNA Damage, Mutagenesis and Cancer

    Directory of Open Access Journals (Sweden)

    Ashis K. Basu

    2018-03-01

    Full Text Available A large number of chemicals and several physical agents, such as UV light and γ-radiation, have been associated with the etiology of human cancer. Generation of DNA damage (also known as DNA adducts or lesions induced by these agents is an important first step in the process of carcinogenesis. Evolutionary processes gave rise to DNA repair tools that are efficient in repairing damaged DNA; yet replication of damaged DNA may take place prior to repair, particularly when they are induced at a high frequency. Damaged DNA replication may lead to gene mutations, which in turn may give rise to altered proteins. Mutations in an oncogene, a tumor-suppressor gene, or a gene that controls the cell cycle can generate a clonal cell population with a distinct advantage in proliferation. Many such events, broadly divided into the stages of initiation, promotion, and progression, which may occur over a long period of time and transpire in the context of chronic exposure to carcinogens, can lead to the induction of human cancer. This is exemplified in the long-term use of tobacco being responsible for an increased risk of lung cancer. This mini-review attempts to summarize this wide area that centers on DNA damage as it relates to the development of human cancer.

  17. Autophagy in DNA Damage Response

    Directory of Open Access Journals (Sweden)

    Piotr Czarny

    2015-01-01

    Full Text Available DNA damage response (DDR involves DNA repair, cell cycle regulation and apoptosis, but autophagy is also suggested to play a role in DDR. Autophagy can be activated in response to DNA-damaging agents, but the exact mechanism underlying this activation is not fully understood, although it is suggested that it involves the inhibition of mammalian target of rapamycin complex 1 (mTORC1. mTORC1 represses autophagy via phosphorylation of the ULK1/2–Atg13–FIP200 complex thus preventing maturation of pre-autophagosomal structures. When DNA damage occurs, it is recognized by some proteins or their complexes, such as poly(ADPribose polymerase 1 (PARP-1, Mre11–Rad50–Nbs1 (MRN complex or FOXO3, which activate repressors of mTORC1. SQSTM1/p62 is one of the proteins whose levels are regulated via autophagic degradation. Inhibition of autophagy by knockout of FIP200 results in upregulation of SQSTM1/p62, enhanced DNA damage and less efficient damage repair. Mitophagy, one form of autophagy involved in the selective degradation of mitochondria, may also play role in DDR. It degrades abnormal mitochondria and can either repress or activate apoptosis, but the exact mechanism remains unknown. There is a need to clarify the role of autophagy in DDR, as this process may possess several important biomedical applications, involving also cancer therapy.

  18. Radiation exposure and chromosome damage

    International Nuclear Information System (INIS)

    Lloyd, D.

    1979-01-01

    Chromosome damage is discussed as a means of biologically measuring radiation exposure to the body. Human lymphocytes are commonly used for this test since the extent of chromosome damage induced is related to the exposure dose. Several hundred lymphocytes are analysed in metaphase for chromosome damage, particularly dicentrics. The dose estimate is made by comparing the observed dicentric yield against calibration curves, previously produced by in vitro irradiation of blood samples to known doses of different types of radiation. This test is useful when there is doubt that the film badge has recorded a reasonable whole body dose and also when there is an absence of any physical data. A case of deliberate exposure is described where the chromosome damage test estimated an exposure of 152 rads. The life span of cell aberrations is also considered. Regular checks on radiotherapy patients and some accidental overdose cases have shown little reduction in the aberration levels over the first six weeks after which the damage disappears slowly with a half-life of about three years. In conclusion, chromosome studies have been shown to be of value in resolving practical problems in radiological protection. (U.K.)

  19. The nucleosome: orchestrating DNA damage signaling and repair within chromatin.

    Science.gov (United States)

    Agarwal, Poonam; Miller, Kyle M

    2016-10-01

    DNA damage occurs within the chromatin environment, which ultimately participates in regulating DNA damage response (DDR) pathways and repair of the lesion. DNA damage activates a cascade of signaling events that extensively modulates chromatin structure and organization to coordinate DDR factor recruitment to the break and repair, whilst also promoting the maintenance of normal chromatin functions within the damaged region. For example, DDR pathways must avoid conflicts between other DNA-based processes that function within the context of chromatin, including transcription and replication. The molecular mechanisms governing the recognition, target specificity, and recruitment of DDR factors and enzymes to the fundamental repeating unit of chromatin, i.e., the nucleosome, are poorly understood. Here we present our current view of how chromatin recognition by DDR factors is achieved at the level of the nucleosome. Emerging evidence suggests that the nucleosome surface, including the nucleosome acidic patch, promotes the binding and activity of several DNA damage factors on chromatin. Thus, in addition to interactions with damaged DNA and histone modifications, nucleosome recognition by DDR factors plays a key role in orchestrating the requisite chromatin response to maintain both genome and epigenome integrity.

  20. Damage Maps of Veneered Zirconia under Simulated Mastication

    Science.gov (United States)

    Kim, Jae-Won; Kim, Joo-Hyung; Janal, Malvin N.; Zhang, Yu

    2016-01-01

    Zirconia based restorations often fracture from chipping and/or delamination of the porcelain veneers. We hypothesize that veneer chipping/delamination is a result of the propagation of near-contact induced partial cone cracks on the occlusal surface under mastication. Masticatory loading involves the opposing tooth sliding along the cuspal inner incline surface with an applied biting force. To test this hypothesis, flat porcelain veneered zirconia plates were cemented to dental composites and cyclically loaded (contact–slide–liftoff) at an inclination angle as a simplified model of zirconia based restorations under occlusion. In the light of in-situ observation of damage evolution in a transparent glass/zirconia/polycarbonate trilayer, postmortem damage evaluation of porcelain/zirconia/composite trilayers using a sectioning technique revealed that deep penetrating occlusal surface partial cone fracture is the predominant fracture mode of porcelain veneers. Clinical relevance is discussed. PMID:19029080

  1. Ion irradiation damage in ilmenite under cryogenic conditions

    International Nuclear Information System (INIS)

    Mitchell, J.N.; Yu, N.; Devanathan, R.; Sickafus, K.E.; Nastasi, M.A.

    1996-01-01

    A natural single crystal of ilmenite was irradiated at 100 K with 200 keV Ar 2+ . Rutherford backscattering spectroscopy and ion channeling with 2 MeV He + ions were used to monitor damage accumulation in the surface region of the implanted crystal. At an irradiation fluence of 1 x 10 15 Ar 2+ cm -2 , considerable near-surface He + ion dechanneling was observed, to the extent that ion yield from a portion of the aligned crystal spectrum reached the yield level of a random spectrum. This observation suggests that the near-surface region of the crystal was amorphized by the implantation. Cross-sectional transmission electron microscopy and electron diffraction on this sample confirmed the presence of a 150 mm thick amorphous layer. These results are compared to similar investigations on geikielite (MgTiO 3 ) and spinel (MgAl 2 O 4 ) to explore factors that may influence radiation damage response in oxides

  2. Periodontal tissue damage in smokers

    Directory of Open Access Journals (Sweden)

    Hutojo Djajakusuma

    2006-09-01

    Full Text Available Dental plaque is the primary etiological factor in periodontal diseases. However, there are many factors that can modify how an individual periodontal tissue will respond to the accumulation of dental plaque. Among such risk factors, there is increasing evidence that smoking tobacco products alters the expression and rate of progression of periodontal diseases. The aim of this study was to find out the loss of periodontal tissue adhesion in smokers by measuring pocket depth using probe, and by measuring alveolar bone damage using Bone Loss Score (BLS radiographic methods on teeth 12, 11, 21, 22, 32, 31, 41, 42. Based on T Test statistical analysis, there were significant differences in pocket depth damage of alveolar bone in smokers and non smokers. In conclusion there were increasing pocket depth and alveolar bone damage in smokers.

  3. Innovative repair of subsidence damage

    International Nuclear Information System (INIS)

    Marino, G.G.

    1992-01-01

    In order to improve handling of subsidence damages the Illinois Mine Subsidence Insurance Fund supported the development of novel cost-effective methods of repair. The research in developing the repairs was directed towards the most common and costly damages that had been observed. As a result repair techniques were designed for structurally cracked foundations in the tension zone; structurally cracked foundations in the compression zone; and damaged or undamaged tilted foundations. When appropriate the postulated methods would result in: 1. significant cost savings (over conventional procedures); 2. a structural capacity greater than when the foundation was uncracked; and 3. an aesthetic appeal. All the postulated repair methodologies were laboratory and/or field tested. This paper will summarize the essentials of each technique developed and the test results

  4. The CATDAT damaging earthquakes database

    Directory of Open Access Journals (Sweden)

    J. E. Daniell

    2011-08-01

    Full Text Available The global CATDAT damaging earthquakes and secondary effects (tsunami, fire, landslides, liquefaction and fault rupture database was developed to validate, remove discrepancies, and expand greatly upon existing global databases; and to better understand the trends in vulnerability, exposure, and possible future impacts of such historic earthquakes.

    Lack of consistency and errors in other earthquake loss databases frequently cited and used in analyses was a major shortcoming in the view of the authors which needed to be improved upon.

    Over 17 000 sources of information have been utilised, primarily in the last few years, to present data from over 12 200 damaging earthquakes historically, with over 7000 earthquakes since 1900 examined and validated before insertion into the database. Each validated earthquake includes seismological information, building damage, ranges of social losses to account for varying sources (deaths, injuries, homeless, and affected, and economic losses (direct, indirect, aid, and insured.

    Globally, a slightly increasing trend in economic damage due to earthquakes is not consistent with the greatly increasing exposure. The 1923 Great Kanto ($214 billion USD damage; 2011 HNDECI-adjusted dollars compared to the 2011 Tohoku (>$300 billion USD at time of writing, 2008 Sichuan and 1995 Kobe earthquakes show the increasing concern for economic loss in urban areas as the trend should be expected to increase. Many economic and social loss values not reported in existing databases have been collected. Historical GDP (Gross Domestic Product, exchange rate, wage information, population, HDI (Human Development Index, and insurance information have been collected globally to form comparisons.

    This catalogue is the largest known cross-checked global historic damaging earthquake database and should have far-reaching consequences for earthquake loss estimation, socio-economic analysis, and the global

  5. The CATDAT damaging earthquakes database

    Science.gov (United States)

    Daniell, J. E.; Khazai, B.; Wenzel, F.; Vervaeck, A.

    2011-08-01

    The global CATDAT damaging earthquakes and secondary effects (tsunami, fire, landslides, liquefaction and fault rupture) database was developed to validate, remove discrepancies, and expand greatly upon existing global databases; and to better understand the trends in vulnerability, exposure, and possible future impacts of such historic earthquakes. Lack of consistency and errors in other earthquake loss databases frequently cited and used in analyses was a major shortcoming in the view of the authors which needed to be improved upon. Over 17 000 sources of information have been utilised, primarily in the last few years, to present data from over 12 200 damaging earthquakes historically, with over 7000 earthquakes since 1900 examined and validated before insertion into the database. Each validated earthquake includes seismological information, building damage, ranges of social losses to account for varying sources (deaths, injuries, homeless, and affected), and economic losses (direct, indirect, aid, and insured). Globally, a slightly increasing trend in economic damage due to earthquakes is not consistent with the greatly increasing exposure. The 1923 Great Kanto (214 billion USD damage; 2011 HNDECI-adjusted dollars) compared to the 2011 Tohoku (>300 billion USD at time of writing), 2008 Sichuan and 1995 Kobe earthquakes show the increasing concern for economic loss in urban areas as the trend should be expected to increase. Many economic and social loss values not reported in existing databases have been collected. Historical GDP (Gross Domestic Product), exchange rate, wage information, population, HDI (Human Development Index), and insurance information have been collected globally to form comparisons. This catalogue is the largest known cross-checked global historic damaging earthquake database and should have far-reaching consequences for earthquake loss estimation, socio-economic analysis, and the global reinsurance field.

  6. Radiation-induced liver damage

    International Nuclear Information System (INIS)

    Marcial, V.A.; Santiago-Delpin, E.A.; Lanaro, A.E.; Castro-Vita, H.; Arroyo, G.; Moscol, J.A.; Gomez, C.; Velazquez, J.; Prado, K.

    1977-01-01

    Due to the recent increase in the use of radiation therapy in the treatment of cancer with or without chemotherapy, the risk of liver radiation damage has become a significant concern for the radiotherapist when the treated tumour is located in the upper abdomen or lower thorax. Clinically evident radiation liver damage may result in significant mortality, but at times patients recover without sequelae. The dose of 3000 rads in 3 weeks to the entire liver with 5 fractions per week of 200 rads each, seems to be tolerated well clinically by adult humans. Lower doses may lead to damage when used in children, when chemotherapy is added, as in recent hepatectomy cases, and in the presence of pre-existent liver damage. Reduced fractionation may lead to increased damage. Increased fractionation, limitation of the dose delivered to the entire liver, and restriction of the high dose irradiation volume may afford protection. With the aim of studying the problems of hepatic radiation injury in humans, a project of liver irradiation in the dog is being conducted. Mongrel dogs are being conditioned, submitted to pre-irradiation studies (haemogram, blood chemistry, liver scan and biopsy), irradiated under conditions resembling human cancer therapy, and submitted to post-irradiation evaluation of the liver. Twenty-two dogs have been entered in the study but only four qualify for the evaluation of all the study parameters. It has been found that dogs are susceptible to liver irradiation damage similar to humans. The initial mortality has been high mainly due to non-radiation factors which are being kept under control at the present phase of the study. After the initial experiences, the study will involve variations in total dose and fractionation, and the addition of anticoagulant therapy for possible prevention of radiation liver injury. (author)

  7. Radiation damage in plastic scintillators

    International Nuclear Information System (INIS)

    Majewski, S.

    1990-01-01

    Results of radiation damage studies in plastic scintillators are reviewed and critically analyzed from the point of view of applications of plastic scintillators in calorimetric detectors for the SSC. Damage to transmission and to fluorescent yield in different conditions is discussed. New directions in R ampersand D are outlined. Several examples are given of the most recent data on the new scintillating materials made with old and new plastics and fluors, which are exhibiting significantly improved radiation resistance. With a present rate of a vigorous R D programme, the survival limits in the vicinity of 100 MRad seem to be feasible within a couple of years

  8. Atom bombs and genetic damage

    International Nuclear Information System (INIS)

    Berry, R.J.

    1982-01-01

    Comments are made on a 1981 review on genetic damage in the off-spring of the atom bomb survivors in Hiroshima and Nagasaki. The main criticisms of the review concerned, 1) the 'minimal' doubling dose value for radiation-induced mutation in man, 2) the gametic doubling dose value for sex chromosome aneuploidy and 3) the validity of trebling an observed acute doubling dose to measure the effect of chronic irradiation. The firmest conclusion which may be deduced from the studies on A-bomb survivors is that humans are fairly resistant to genetic damage from radiation. (U.K.)

  9. Influence of intensity fluctuations on laser damage in optical materials

    International Nuclear Information System (INIS)

    Koldunov, M.F.; Manenkov, A.A.; Pocotilo, I.L.

    1995-01-01

    A study is reported of the influence of temporal fluctuations of laser radiation on the development of thermal explosion of absorbing inclusions and on the statistical properties of the laser induced damage in transparent dielectrics. A fluctuation time scale in which the fluctuations affect the thermal explosion of inclusions is established. An analysis is made of the conditions ensuring control of temporal fluctuations of laser radiation so as to eliminate their influence on the experimental statistical relationships governing laser damage associated with the distribution of absorbing inclusions in the bulk and on the surface of a sample

  10. Multiple pulse nanosecond laser induced damage threshold on hybrid mirrors

    Science.gov (United States)

    Vanda, Jan; Muresan, Mihai-George; Bilek, Vojtech; Sebek, Matej; Hanus, Martin; Lucianetti, Antonio; Rostohar, Danijela; Mocek, Tomas; Škoda, Václav

    2017-11-01

    So-called hybrid mirrors, consisting of broadband metallic surface coated with dielectric reflector designed for specific wavelength, becoming more important with progressing development of broadband mid-IR sources realized using parametric down conversion system. Multiple pulse nanosecond laser induced damage on such mirrors was tested by method s-on-1, where s stands for various numbers of pulses. We show difference in damage threshold between common protected silver mirrors and hybrid silver mirrors prepared by PVD technique and their variants prepared by IAD. Keywords: LIDT,

  11. Application of a Brittle Damage Model to Normal Plate-on-Plate Impact

    National Research Council Canada - National Science Library

    Raftenberg, Martin N

    2005-01-01

    .... For a range of values for the material constants introduced by the damage model, the target's free-surface velocity showed a gradual increase over time following the arrival of the initial compressive shock.

  12. Damage Propagation Modeling for Aircraft Engine Run-to-Failure Simulation

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper describes how damage propagation can be modeled within the modules of aircraft gas turbine engines. To that end, response surfaces of all sensors are...

  13. Damage invariant and high security acquisition of the internal fingerprint using optical coherence tomography

    CSIR Research Space (South Africa)

    Darlow, Luke N

    2016-11-01

    Full Text Available representation they offer. Using an emerging fingerprint acquisition technology – optical coherence tomography – to access an internal fingerprint under the skin surface, this paper serves to address two limitations of conventional scanners: fingertip skin damage...

  14. Short-pulse CO2-laser damage studies of NaCl and KCl windows

    International Nuclear Information System (INIS)

    Newnam, B.E.; Nowak, A.V.; Gill, D.H.

    1979-01-01

    The damage resistance of bare surfaces and the bulk interior of NaCl and KCl windows was measured with a short-pulse CO 2 laser at 10.6 μm. Parametric studies with 1.7-ns pulses indicated that adsorbed water was probably the limiting agent on surface thresholds in agreement with previous studies at long pulsewidths. Rear-surface thresholds up to 7 J/cm 2 were measured for polished NaCl windows, whereas KCl surfaces damaged at approximately 60% of this level. The breakdown electric-field thresholds of exit surfaces were only 50% of the value of the bulk materials. The pulsewidth dependence of surface damage from 1 to 65 ns, in terms of incident laser fluence, increased as t/sup 1/3/

  15. A review of thermographic techniques for damage investigation in composites

    Directory of Open Access Journals (Sweden)

    Laura Vergani

    2014-01-01

    Full Text Available The aim of this work is a review of scientific results in the literature, related to the application of thermographic techniques to composite materials. Thermography is the analysis of the surface temperature of a body by infrared rays detection via a thermal-camera. The use of this technique is mainly based on the modification of the surface temperature of a material, when it is stimulated by means of a thermal or mechanical external source. The presence of defects, in fact, induces a localized variation in its temperature distribution and, then, the measured values of the surface temperature can be used to localize and evaluate the dimensions and the evolution of defects. In the past, many applications of thermography were proposed on homogeneous materials, but only recently this technique has also been extended to composites. In this work several applications of thermography to fibres reinforced plastics are presented. Thermographic measurements are performed on the surface of the specimens, while undergoing static and dynamic tensile loading. The joint analysis of thermal and mechanical data allows one to assess the damage evolution and to study the damage phenomenon from both mechanical and energetic viewpoints. In particular, one of the main issues is to obtain information about the fatigue behaviour of composite materials, by following an approach successfully applied to homogenous materials. This approach is based on the application of infrared thermography on specimens subjected to static or stepwise dynamic loadings and on the definition of a damage stress, D, that is correlated to the fatigue strength of the material. A wide series of experimental fatigue tests has been carried out to verify if the value of the damage stress, D, is correlated with the fatigue strength of the material. The agreement between the different values is good, showing the reliability of the presented thermographic techniques, to the study of composite

  16. Modeling of Corrosion-induced Concrete Damage

    DEFF Research Database (Denmark)

    Thybo, Anna Emilie A.; Michel, Alexander; Stang, Henrik

    2013-01-01

    In the present paper a finite element model is introduced to simulate corrosion-induced damage in concrete. The model takes into account the penetration of corrosion products into the concrete as well as non-uniform formation of corrosion products around the reinforcement. To ac-count for the non...... of corrosion products affects both the time-to cover cracking and the crack width at the concrete surface.......In the present paper a finite element model is introduced to simulate corrosion-induced damage in concrete. The model takes into account the penetration of corrosion products into the concrete as well as non-uniform formation of corrosion products around the reinforcement. To ac-count for the non......-uniform formation of corrosion products at the concrete/reinforcement interface, a deterministic approach is used. The model gives good estimates of both deformations in the con-crete/reinforcement interface and crack width when compared to experimental data. Further, it is shown that non-uniform deposition...

  17. Engineering Polymer Blends for Impact Damage Mitigation

    Science.gov (United States)

    Gordon, Keith L.; Smith, Russell W.; Working, Dennis C.; Siochi, Emilie J.

    2016-01-01

    Structures containing polymers such as DuPont's Surlyn® 8940, demonstrate puncture healing when impacted by a 9 millimeter projectile traveling from speeds near 300 meters per second (1,100 feet per second) to hypervelocity impacts in the micrometeoroid velocity range of 5 kilometers per second (16,000 feet per second). Surlyn® 8940 puncture heals over a temperature range of minus 30 degrees Centigrade to plus 70 degrees Centigrade and shows potential for use in pressurized vessels subject to impact damage. However, such polymers are difficult to process and limited in applicability due to their low thermal stability, poor chemical resistance and overall poor mechanical properties. In this work, several puncture healing engineered melt formulations were developed. Moldings of melt blend formulations were impacted with a 5.56 millimeter projectile with a nominal velocity of 945 meters per second (3,100 feet per second) at about 25 degrees Centigrade, 50 degrees Centigrade and 100 degrees Centigrade, depending upon the specific blend being investigated. Self-healing tendencies were determined using surface vacuum pressure tests and tensile tests after penetration using tensile dog-bone specimens (ASTM D 638-10). For the characterization of tensile properties both pristine and impacted specimens were tested to obtain tensile modulus, yield stress and tensile strength, where possible. Experimental results demonstrate a range of new puncture healing blends which mitigate damage in the ballistic velocity regime.

  18. Damage observation in a high-manganese austenitic TWIP steel by synchrotron radiation computed tomography

    International Nuclear Information System (INIS)

    Lorthios, J.; Nguyen, F.; Gourgues, A.-F.; Morgeneyer, T.F.; Cugy, P.

    2010-01-01

    Internal damage below the fracture surface of a multiaxial specimen made of twinning-induced plasticity (TWIP) steel was observed by three-dimensional X-ray microtomography as very elongated 'primary' voids. Specific tools for the local damage analysis were developed. A gradient in void volume fraction was measured from the fracture surface down to the bulk of the scanned volume (from ∼0.06% to 90% in area fraction), indicating strongly localized final fracture.

  19. Extreme Ultraviolet (EUV) induced surface chemistry on Ru

    NARCIS (Netherlands)

    Liu, Feng; Sturm, Jacobus Marinus; Lee, Christopher James; Bijkerk, Frederik

    2013-01-01

    EUV photon induced surface chemistry can damage multilayer mirrors causing reflectivity loss and faster degradation. EUV photo chemistry involves complex processes including direct photon induced surface chemistry and secondary electron radiation chemistry. Current cleaning techniques include dry

  20. Damage limits of accelerator equipment

    CERN Document Server

    Rosell, Gemma

    2014-01-01

    Beam losses occur in particle accelerators for various reasons. The effect of lost particles on accelerator equipment becomes more severe with the increasing energies and intensities. The present study is focused on the damage potential of the proton beam as a function of particle energy and beam size. Injection and extraction energies of different accelerators at CERN were considered.

  1. DNA damage by Auger emitters

    International Nuclear Information System (INIS)

    Martin, R.F.; d'Cunha, Glenn; Gibbs, Richard; Murray, Vincent; Pardee, Marshall; Allen, B.J.

    1988-01-01

    125 I atoms can be introduced at specific locations along a defined DNA target molecule, either by site-directed incorporation of an 125 I-labelled deoxynucleotide or by binding of an 125 I-labelled sequence-selective DNA ligand. After allowing accumulation of 125 I decay-induced damage to the DNA, application of DNA sequencing techniques enables positions of strand breaks to be located relative to the site of decay, at a resolution corresponding to the distance between adjacent nucleotides [0.34 nm]. Thus, DNA provides a molecular framework to analyse the extent of damage following [averaged] individual decay events. Results can be compared with energy deposition data generated by computer-simulation methods developed by Charlton et al. The DNA sequencing technique also provides information about the chemical nature of the termini of the DNA chains produced following Auger decay-induced damage. In addition to reviewing the application of this approach to the analysis of 125 I decay induced DNA damage, some more recent results obtained by using 67 Ga are also presented. (author)

  2. Preparation of bubble damage detectors

    International Nuclear Information System (INIS)

    Tu Caiqing; Guo Shilun; Wang Yulan; Hao Xiuhong; Chen Changmao; Su Jingling

    1997-01-01

    Bubble damage detectors have been prepared by using polyacrylamide as detector solid and freon as detector liquid. Tests show that the prepared detectors are sensitive to fast neutrons and have proportionality between bubble number and neutron fluence within a certain range of neutron fluence. Therefore, it can be used as a fast neutron detector and a dosimeter

  3. Development of nondestructive evaluation of creep-fatigue damage in SUS316 stainless steel

    International Nuclear Information System (INIS)

    Shoji, Tetsuo; Kawahara, Tetsuji; Awano, Masakazu; Sato, Yasumoto

    1999-01-01

    Creep-fatigue is a fatal failure mode of high temperature structural materials. It is recognized that the law of linear damage, according to which creep-fatigue damage is expressed by the sum of the creep damage and the fatigue damage, is inadequate to evaluate creep-fatigue damage. This is due to the fact that the law of linear damage does not include the effect of interaction between the creep damage and the fatigue damage. Consequently, development of direct measurement of damage accumulation on the sample of interest is required for plant life evaluation. In this study, the induced current focusing potential drop (ICFPD) technique was used to evaluate the depth of small surface cracks in SUS316FR stainless steel which was subjected to creep-fatigue damage. It is shown that the potential drop increased during the micro-crack initiation and propagation. Correspondingly, the ICFPD technique applied to estimate micro-crack depth changes was used to accurately evaluate the residual life of creep-fatigue damaged structural materials. (author)

  4. Implementation of an anisotropic damage material model using general second order damage tensor

    NARCIS (Netherlands)

    Niazi, Muhammad Sohail; Mori, K.; Wisselink, H.H.; Pietrzyk, M.; Kusiak, J.; Meinders, Vincent T.; ten Horn, Carel; Majta, J.; Hartley, P.; Lin, J.

    2010-01-01

    Damage in metals is mainly the process of the initiation and growth of voids. With the growing complexity in materials and forming proc-esses, it becomes inevitable to include anisotropy in damage (tensorial damage variable). Most of the anisotropic damage models define the damage tensor in the

  5. Electrical impedance tomography-based sensing skin for quantitative imaging of damage in concrete

    International Nuclear Information System (INIS)

    Hallaji, Milad; Pour-Ghaz, Mohammad; Seppänen, Aku

    2014-01-01

    This paper outlines the development of a large-area sensing skin for damage detection in concrete structures. The developed sensing skin consists of a thin layer of electrically conductive copper paint that is applied to the surface of the concrete. Cracking of the concrete substrate results in the rupture of the sensing skin, decreasing its electrical conductivity locally. The decrease in conductivity is detected with electrical impedance tomography (EIT) imaging. In previous works, electrically based sensing skins have provided only qualitative information on the damage on the substrate surface. In this paper, we study whether quantitative imaging of the damage is possible. We utilize application-specific models and computational methods in the image reconstruction, including a total variation (TV) prior model for the damage and an approximate correction of the modeling errors caused by the inhomogeneity of the painted sensing skin. The developed damage detection method is tested experimentally by applying the sensing skin to polymeric substrates and a reinforced concrete beam under four-point bending. In all test cases, the EIT-based sensing skin provides quantitative information on cracks and/or other damages on the substrate surface: featuring a very low conductivity in the damage locations, and a reliable indication of the lengths and shapes of the cracks. The results strongly support the applicability of the painted EIT-based sensing skin for damage detection in reinforced concrete elements and other substrates. (paper)

  6. Effects of laser radiation on surfaces and coatings

    International Nuclear Information System (INIS)

    Lowdermilk, W.H.

    1985-01-01

    A summary is given of the principal aspects of laser-induced damage to polished optical surfaces and dielectric, thin-film, high-reflectivity and antireflective coatings. Methods for producing porous antireflective surfaces and coatings and their damage properties are also reviewed. Finally, new areas of basic research to solve current and future problems are addressed

  7. Quantification of change in vocal fold tissue stiffness relative to depth of artificial damage.

    Science.gov (United States)

    Rohlfs, Anna-Katharina; Schmolke, Sebastian; Clauditz, Till; Hess, Markus; Müller, Frank; Püschel, Klaus; Roemer, Frank W; Schumacher, Udo; Goodyer, Eric

    2017-10-01

    To quantify changes in the biomechanical properties of human excised vocal folds with defined artificial damage. The linear skin rheometer (LSR) was used to obtain a series of rheological measurements of shear modulus from the surface of 30 human cadaver vocal folds. The tissue samples were initially measured in a native condition and then following varying intensities of thermal damage. Histological examination of each vocal fold was used to determine the depth of artificial alteration. The measured changes in stiffness were correlated with the depth of cell damage. For vocal folds in a pre-damage state the shear modulus values ranged from 537 Pa to 1,651 Pa (female) and from 583 Pa to 1,193 Pa (male). With increasing depth of damage from the intermediate layer of the lamina propria (LP), tissue stiffness increased consistently (compared with native values) following application of thermal damage to the vocal folds. The measurement showed an increase of tissue stiffness when the depth of tissue damage was extending from the intermediate LP layer downwards. Changes in the elastic characteristics of human vocal fold tissue following damage at defined depths were demonstrated in an in vitro experiment. In future, reproducible in vivo measurements of elastic vocal fold tissue alterations may enable phonosurgeons to infer the extent of subepithelial damage from changes in surface elasticity.

  8. Analysis of localized damage in creep rupture

    International Nuclear Information System (INIS)

    Wang Zhengdong; Wu Dongdi

    1992-01-01

    Continuum Damage Mechanics studies the effect of distributed defects, whereas the failure of engineering structures is usually caused by local damage. In this paper, an analysis of localized damage in creep rupture is carried out. The material tested is a 2 1/4Cr-1Mo pressure vessel steel and the material constants necessary for damage analysis are evaluated. Notched specimens are used to reflect localized damage in creep rupture and the amount of damage is measured using DCPD method. Through FEM computation, stress components and effective stress in the region of notch root are evaluated and it is found that the von Mises effective stress can represent the damage effective stress in the analysis of localized creep damage. It is possible to develop a method for the assessment of safety of pressure vessels under creep through localized creep damage analysis. (orig.)

  9. Grinding damage assessment for CAD-CAM restorative materials.

    Science.gov (United States)

    Curran, Philippe; Cattani-Lorente, Maria; Anselm Wiskott, H W; Durual, Stéphane; Scherrer, Susanne S

    2017-03-01

    To assess surface/subsurface damage after grinding with diamond discs on five CAD-CAM restorative materials and to estimate potential losses in strength based on crack size measurements of the generated damage. The materials tested were: Lithium disilicate (LIT) glass-ceramic (e.max CAD), leucite glass-ceramic (LEU) (Empress CAD), feldspar ceramic (VM2) (Vita Mark II), feldspar ceramic-resin infiltrated (EN) (Enamic) and a composite reinforced with nano ceramics (LU) (Lava Ultimate). Specimens were cut from CAD-CAM blocs and pair-wise mirror polished for the bonded interface technique. Top surfaces were ground with diamond discs of respectively 75, 54 and 18μm. Chip damage was measured on the bonded interface using SEM. Fracture mechanics relationships were used to estimate fracture stresses based on average and maximum chip depths assuming these to represent strength limiting flaws subjected to tension and to calculate potential losses in strength compared to manufacturer's data. Grinding with a 75μm diamond disc induced on a bonded interface critical chips averaging 100μm with a potential strength loss estimated between 33% and 54% for all three glass-ceramics (LIT, LEU, VM2). The softer materials EN and LU were little damage susceptible with chips averaging respectively 26μm and 17μm with no loss in strength. Grinding with 18μm diamond discs was still quite detrimental for LIT with average chip sizes of 43μm and a potential strength loss of 42%. It is essential to understand that when grinding glass-ceramics or feldspar ceramics with diamond discs surface and subsurface damage are induced which have the potential of lowering the strength of the ceramic. Careful polishing steps should be carried out after grinding especially when dealing with glass-ceramics. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  10. Low voltage initiation of damaging arcs between electrical contacts

    International Nuclear Information System (INIS)

    Cuthrell, R.E.

    1975-07-01

    Metallic arcs were found to precede the firm contacting of electrical contacts which were closed without bounce. When the open-circuit voltages were below the ionization potential, the initiation of these arcs was found to depend on the presence of asperities on the surfaces and on asperity contracting, melting, and pinching off by magnetic forces. The arc is thought to be initiated inductively when the molten metallic asperity contact is pinched off, and the electrode damage is similar to that produced by the arcing of opening contacts. Arcing could not be produced for exceptionally smooth surfaces, or, for rough surfaces when the open-circuit potential was below the melting voltages of the electrode metals. In order to prevent damage to contact surfaces by melting or arcing, it is suggested that test potentials be limited to below the melting voltages, that the current be limited, the test circuits be designed to prevent inductively generated high voltage transients, and the contact surfaces be very smooth. In order to facilitate arc initiation in arc welding applications, it is suggested that the surfaces of electrodes and work pieces be roughened. (U.S.)

  11. Multiphysics model of thermomechanical and helium-induced damage of tungsten during plasma heat transients

    Energy Technology Data Exchange (ETDEWEB)

    Crosby, Tamer, E-mail: tcrosby@ucla.edu; Ghoniem, Nasr M., E-mail: ghoniem@ucla.edu

    2013-11-15

    A combination of transient heating and bombardment by helium and hydrogen atoms has been experimentally proven to lead to severe surface and sub-surface damage. We developed a computational model to determine the relationship between the thermomechanical loading conditions and the onset of damage and failure of tungsten surfaces. The model is based on a thermoelasticity fracture damage approach that was developed using the phase field method. The model simulates the distribution of helium bubbles inside the grains and on grain boundaries using space-dependent rate theory. In addition, the model is coupled with a transient heat conduction analysis for temperature distributions inside the material. The results show the effects of helium bubbles on reducing tungsten surface energy. Further, a temperature gradient in the material equals to 10 K/μm, resulted in deep cracks propagating from the tungsten surface.

  12. Investigation of cutting-induced damage in CMC bend bars

    Directory of Open Access Journals (Sweden)

    Neubrand A.

    2015-01-01

    Full Text Available Ceramic matrix composites (“CMC” with a strong fibre-matrix interface can be made damage-tolerant by introducing a highly porous matrix. Such composites typically have only a low interlaminar shear strength, which can potentially promote damage when preparing specimens or components by cutting. In order to investigate the damage induced by different cutting methods, waterjet cutting with and without abrasives, laser-cutting, wire eroding and cutoff grinding were used to cut plates of two different CMCs with a matrix porosity up to 35 vol.-%. For each combination of cutting method and composite, the flexural and interlaminar shear strength of the resulting specimens was determined. Additionally, the integrity of the regions near the cut surfaces was investigated by high-resolution x-ray computer tomography. It could be shown that the geometrical quality of the cut is strongly affected by the cutting method employed. Laser cut and waterjet cut specimens showed damage and delaminations near the cut surface leading to a reduced interlaminar shear strength of short bend bars in extreme cases.

  13. Subsurface damage mechanism of high speed grinding process in single crystal silicon revealed by atomistic simulations

    International Nuclear Information System (INIS)

    Li, Jia; Fang, Qihong; Zhang, Liangchi; Liu, Youwen

    2015-01-01

    Highlights: • Molecular dynamic model of nanoscale high speed grinding of silicon workpiece has been established. • The effect of grinding speed on subsurface damage and grinding surface integrity by analyzing the chip, dislocation movement, and phase transformation during high speed grinding process are thoroughly investigated. • Subsurface damage is studied by the evolution of surface area at first time for more obvious observation on transition from ductile to brittle. • The hydrostatic stress and von Mises stress by the established analytical model are studied subsurface damage mechanism during nanoscale grinding. - Abstract: Three-dimensional molecular dynamics (MD) simulations are performed to investigate the nanoscale grinding process of single crystal silicon using diamond tool. The effect of grinding speed on subsurface damage and grinding surface integrity by analyzing the chip, dislocation movement, and phase transformation are studied. We also establish an analytical model to calculate several important stress fields including hydrostatic stress and von Mises stress for studying subsurface damage mechanism, and obtain the dislocation density on the grinding subsurface. The results show that a higher grinding velocity in machining brittle material silicon causes a larger chip and a higher temperature, and reduces subsurface damage. However, when grinding velocity is above 180 m s −1 , subsurface damage thickness slightly increases because a higher grinding speed leads to the increase in grinding force and temperature, which accelerate dislocation nucleation and motion. Subsurface damage is studied by the evolution of surface area at first time for more obvious observation on transition from ductile to brittle, that provides valuable reference for machining nanometer devices. The von Mises stress and the hydrostatic stress play an important role in the grinding process, and explain the subsurface damage though dislocation mechanism under high

  14. Experiment and numerical simulation of welding induced damage: stainless steel 15-5PH

    International Nuclear Information System (INIS)

    Wu, T.

    2007-11-01

    The objective of this study is the prediction of damage and residual stresses induced by hot processing which leads to phase transformation in martensitic stainless steel. This study firstly concerns the modelling of the damage of material induced by a complex history of thermo-elastoplastic multiphase in heat-affected-zone (HAZ) of welding. In this work, a two-scale mode of elastoplastic damage multiphase was developed in the framework of thermodynamics of irreversible process. The constitutive equations are coupling with ductile damage, elasto-plasticity, phase transformation, and transformation plasticity. Besides, a damage equation was proposed based on the Lemaitre's damage model in the framework of continuum damage mechanics. The experiments of 15-5PH were implemented for the identification of phase transformation, transformation plasticity and damage models. Tensile tests of round specimens were used to identify the parameters of damage model as well as mechanical behaviours at various temperatures. Tests of flat notched specimen were designed to provide the validation of damage model and strain localization using three dimensional image correlation technologies. In addition, microscopic analysis was performed to provide microstructure characterization of 15-5PH and to discover the damage mechanism. Finally the numerical simulation was performed in the code CAST3M of CEA. On the one hand, numerical verification of the flat notched plates was implemented and compared with experimental results. On the other hand, we used the two-scale model including phase transformation, transformation plasticity and damage to simulate the level of residual stresses of a disk made of 15-5PH metal heated by laser. The internal variables, such as strain, stress, damage, were successfully traced in the simulation of two-scale model. The simulation results showed the transformation plasticity changes the level of residual stresses and should not be negligible; damage decreases

  15. Genetic damage following nuclear war

    International Nuclear Information System (INIS)

    Oftedal, P.

    1984-01-01

    Genetic damage may be caused by ionizing radiation from the exploding bomb itself, or from radioactive nuclides released or formed in the explosion. Long-wave radiation in the heat flash and physical force do not contribute. Thus only a small fraction of the energy of the explosion - fission or fusion- can cause genetic damage. Neutron irradiation is generally found to be 5-20 times more efficient than gamma irradiation for the same absorbed dose. Fetuses and children are generally more radiosensitive than adults. Exposure of gonads during the proliferative stage of gonad growth may conceivably lead to a ''fluctuation test'' effect, so that a gonad may contain a sector of cells carrying identical mutations. A corresponding development may take place if the gonad stem cell population has been severely depleted by an acute exposure and recovers

  16. Apportioning liability for transborder damages

    International Nuclear Information System (INIS)

    Krause-Ablass, W.-D.

    1988-01-01

    The legal situation in the case of cross border damage being caused by reactor accidents or transportation of nuclear material through more than one country is analysed. Two questions have to be asked - which country's courts have jurisdiction over the claims for damage? and which law is applicable? In considering the jurisdiction problem, the Paris and Vienna Conventions are discussed and also other rules of jurisdiction. The way the law is applicable is discussed in the second section. When the action for liability is based on the Paris or Vienna Convention the issue of reciprocity may arise and this is discussed. After a nuclear incident a potential plaintiff may have a choice amongst various jurisdictions and various available laws. Success may depend on the right choice of the forum chosen. This is illustrated by two examples. (U.K.)

  17. Genetic doping and health damages.

    Science.gov (United States)

    Fallahi, Aa; Ravasi, Aa; Farhud, Dd

    2011-01-01

    Use of genetic doping or gene transfer technology will be the newest and the lethal method of doping in future and have some unpleasant consequences for sports, athletes, and outcomes of competitions. The World Anti-Doping Agency (WADA) defines genetic doping as "the non-therapeutic use of genes, genetic elements, and/or cells that have the capacity to enhance athletic performance ". The purpose of this review is to consider genetic doping, health damages and risks of new genes if delivered in athletes. This review, which is carried out by reviewing relevant publications, is primarily based on the journals available in GOOGLE, ELSEVIER, PUBMED in fields of genetic technology, and health using a combination of keywords (e.g., genetic doping, genes, exercise, performance, athletes) until July 2010. There are several genes related to sport performance and if they are used, they will have health risks and sever damages such as cancer, autoimmunization, and heart attack.

  18. Civil liability for nuclear damage

    International Nuclear Information System (INIS)

    1963-01-01

    An international Convention on Civil Liability for Nuclear Damage was adopted in Vienna on 19 May 1963 by a sixty-nation conference convened by the International Atomic Energy Agency. The Convention, which is subject to ratification by the States signing it, will come into force three months after the deposit of the fifth instrument of ratification. The Convention is designee only to establish minimum rules regarding civil liability for nuclear damage; it may thus well be described as a framework convention, the main provisions of which represent the essential common denomination acceptable to as many States as possible. It leaves wide scope for national legislation and regional arrangements with a view to implementing these provisions The Convention does not purport to create a uniform civil law in this field, but it contains the minimal essential for protection of the public and forms the legal basis for uniform world-wide liability rules

  19. Damaging brands through market research:

    DEFF Research Database (Denmark)

    Horn, C.; Brem, Alexander; Ivens, B.

    2014-01-01

    Purpose – The purpose of this paper is to investigate the possibility of using the new marketing research tool of prediction markets (PMs), which integrates customers to into the marketing research process. The research questions are: does taking part in PMs influence customers’ brand perception......? Is there a danger of damaging a brand through this tool? Design/methodology/approach – The paper uses a series of five short-term (less than one hour) and five long-term (three weeks) experimental online PMs where customers are integrated into marketing research and apply a series of online-surveys before and after...... taking part as virtual stock market traders. Subjects of research are taken from the sporting goods industry. Findings – The paper shows that PMs can be used by marketing researchers without the danger of damaging the brand of the products that are subject of the PMs, although customers are being...

  20. Radiation damage in biomolecular systems

    CERN Document Server

    Fuss, Martina Christina

    2012-01-01

    Since the discovery of X-rays and radioactivity, ionizing radiations have been widely applied in medicine both for diagnostic and therapeutic purposes. The risks associated with radiation exposure and handling led to the parallel development of the field of radiation protection. Pioneering experiments done by Sanche and co-workers in 2000 showed that low-energy secondary electrons, which are abundantly generated along radiation tracks, are primarily responsible for radiation damage through successive interactions with the molecular constituents of the medium. Apart from ionizing processes, which are usually related to radiation damage, below the ionization level low-energy electrons can induce molecular fragmentation via dissociative processes such as internal excitation and electron attachment. This prompted collaborative projects between different research groups from European countries together with other specialists from Canada,  the USA and Australia. This book summarizes the advances achieved by these...

  1. A damage-tolerant glass.

    Science.gov (United States)

    Demetriou, Marios D; Launey, Maximilien E; Garrett, Glenn; Schramm, Joseph P; Hofmann, Douglas C; Johnson, William L; Ritchie, Robert O

    2011-02-01

    Owing to a lack of microstructure, glassy materials are inherently strong but brittle, and often demonstrate extreme sensitivity to flaws. Accordingly, their macroscopic failure is often not initiated by plastic yielding, and almost always terminated by brittle fracture. Unlike conventional brittle glasses, metallic glasses are generally capable of limited plastic yielding by shear-band sliding in the presence of a flaw, and thus exhibit toughness-strength relationships that lie between those of brittle ceramics and marginally tough metals. Here, a bulk glassy palladium alloy is introduced, demonstrating an unusual capacity for shielding an opening crack accommodated by an extensive shear-band sliding process, which promotes a fracture toughness comparable to those of the toughest materials known. This result demonstrates that the combination of toughness and strength (that is, damage tolerance) accessible to amorphous materials extends beyond the benchmark ranges established by the toughest and strongest materials known, thereby pushing the envelope of damage tolerance accessible to a structural metal.

  2. Smart accelerometer. [vibration damage detection

    Science.gov (United States)

    Bozeman, Richard J., Jr. (Inventor)

    1994-01-01

    The invention discloses methods and apparatus for detecting vibrations from machines which indicate an impending malfunction for the purpose of preventing additional damage and allowing for an orderly shutdown or a change in mode of operation. The method and apparatus is especially suited for reliable operation in providing thruster control data concerning unstable vibration in an electrical environment which is typically noisy and in which unrecognized ground loops may exist.

  3. Damage-resistant brittle coatings

    Energy Technology Data Exchange (ETDEWEB)

    Lawn, B.R.; Lee, K.S. [National Inst. of Stand. and Technol., Gaithersburg, MD (United States). Mater. Sci. and Eng. Lab.; Chai, H. [Tel Aviv Univ. (Israel). Faculty of Engineering; Pajares, A. [Universidad de Extremadura, Badajoz (Spain). Dept. de Fisica; Kim, D.K. [Korea Advanced Inst. of Science and Technolgy, Taejon (Korea). Dept. of Materials Science and Engineering; Wuttiphan, S. [National Metal and Materials Technology Center, Bangkok (Thailand); Peterson, I.M. [Corning Inc., NY (United States); Hu Xiaozhi [Western Australia Univ., Nedlands, WA (Australia). Dept. of Mechanical and Materials Engineering

    2000-11-01

    Laminate structures consisting of hard, brittle coatings and soft, tough substrates are important in a wide variety of engineering applications, biological structures, and traditional pottery. In this study the authors introduce a new approach to the design of damage-resistant brittle coatings, based on a combination of new and existing relations for crack initiation in well-defined contact-induced stress fields. (orig.)

  4. Analysis of radiation damaged nanocrystals

    International Nuclear Information System (INIS)

    Sitek, J.; Dekan, J.; Sedlackova, K.; Sagatova, A.

    2014-01-01

    Ribbon-shaped specimens of the master alloy were prepared by planar flow casting. The ribbons with nominal composition of (Fe_1_-_xN_x)_8_1Nb_7B_1_2 (x = 0, 0.25, 0.5, 0.75) were about 25 μm thick and 10 mm wide. To achieve nanocrystalline state, the amorphous ribbons were annealed in vacuum at the temperature of 550 grad C for 1 hour. Samples were irradiated by neutrons in nuclear reactor with fluence of 10"1"6 n/cm"2 and 10"1"7 n/cm"2. and by electrons in linear accelerator with dose 1 MGy at the Slovak Medical University. Moessbauer spectra were collected in transmission geometry by a conventional constant-acceleration spectrometer with a "5"7Co(Rh) source. All spectra were measured at room temperature and evaluated by the CONFIT program, which allows simultaneous treatment of crystalline and residual amorphous phase by means of individual lines and distribution of hyperfine components. After summarizing all obtained results, the fluence 10"1"6 n/cm"2 is still not sufficiently high significantly damage amorphous and crystalline structure. This fluence more or less modify the structure than damage. After fluence 10"17"n/cm"2 we observed beginning of the. structural damage. Our results show, that high electron dose also modify the structure of nanocrystaline alloys. In further study of this alloy it would be necessary to find the limit of electron dose under that the alloy is resistant against electron's damage. From point of view Moessbauer spectroscopy the most sensitive parameter is direction of net magnetic moment. (authors)

  5. Quantification of thermal damage in skin tissue

    Institute of Scientific and Technical Information of China (English)

    Xu Feng; Wen Ting; Lu Tianjian; Seffen Keith

    2008-01-01

    Skin thermal damage or skin burns are the most commonly encountered type of trauma in civilian and military communities. Besides, advances in laser, microwave and similar technologies have led to recent developments of thermal treatments for disease and damage involving skin tissue, where the objective is to induce thermal damage precisely within targeted tissue structures but without affecting the surrounding, healthy tissue. Further, extended pain sensation induced by thermal damage has also brought great problem for burn patients. Thus, it is of great importance to quantify the thermal damage in skin tissue. In this paper, the available models and experimental methods for quantification of thermal damage in skin tissue are discussed.

  6. Biologically important radiation damage in DNA

    International Nuclear Information System (INIS)

    Ward, J.F.

    1994-01-01

    Most DNA damage by the hydroxyl radical is confined to the bases, and this base damage represents an important component of locally multiply demanded sites (LMOS). The yields of the major damaged bases have been determined by gas chromatography mass spectrometry. For our propose, it was necessary to convert a known fraction of these damaged bases to strand breaks and then assay these labile sites as the increase in strand break yield over the normally observed level. Three potential agents by which this strategy of conversion of base damage to strand break could be implemented were identified in the original application: 1, Sl nuclease; 2, piperidine; and 3, base damage specific enzymes

  7. Economic measurement of environment damages

    Energy Technology Data Exchange (ETDEWEB)

    Krawiec, F.

    1980-05-01

    The densities, energy consumption, and economic development of the increasing population exacerbate environmental degradation. Air and water pollution is a major environmental problem affecting life and health, outdoor recreation, household soiling, vegetation, materials, and production. The literature review indicated that numerous studies have assessed the physical and monetary damage to populations at risk from excessive concentrations of major air and water pollutants-sulfur dioxide, total suspended particulate matter, oxidants, and carbon monoxide in air; and nutrients, oil, pesticides, and toxic metals and others in water. The measurement of the damages was one of the most controversial issues in pollution abatement. The methods that have been used to estimate the societal value of pollution abatement are: (1) chain of effects, (2) market approaches, and (3) surveys. National gross damages of air pollution of $20.2 billion and of water pollution of $11.1 billion for 1973 are substantial. These best estimates, updated for the economic and demographic conditions, could provide acceptable control totals for estimating and predicting benefits and costs of abating air and water pollution emissions. The major issues to be resolved are: (1) lack of available noneconomic data, (2) theoretical and empirical difficulties of placing a value on human life and health and on benefits such as aesthetics, and (3) lack of available demographic and economic data.

  8. Radiation damage of structural materials

    International Nuclear Information System (INIS)

    Koutsky, J.; Kocik, J.

    1994-01-01

    Maintaining the integrity of nuclear power plants (NPP) is critical in the prevention or control of severe accidents. This monograph deals with both basic groups of structural materials used in the design of light-water nuclear reactors, making the primary safety barriers of NPPs. Emphasis is placed on materials used in VVER-type nuclear reactors: Cr-Mo-V and Cr-Ni-Mo-V steel for reactor pressure vessels (RPV) and Zr-Nb alloys for fuel element cladding. The book is divided into seven main chapters, with the exception of the opening one and the chapter providing phenomenological background for the subject of radiation damage. Chapters 3-6 are devoted to RPV steels and chapters 7-9 to zirconium alloys, analyzing their radiation damage structure, changes of mechanical properties due to neutron irradiation as well as factors influencing the degree of their performance degradation. The recovery of damaged materials is also discussed. Considerable attention is paid to a comparison of VVER-type and western-type light-water materials

  9. Damage-induced tensile instability

    International Nuclear Information System (INIS)

    Hult, J.

    1975-01-01

    The paper presents a unified description of ductile and brittle rupture phenomena in structural components under tensile loading with particular emphasis on creep rupture. Two structural elements are analyzed in detail: 1) the uniform tensile bar subject to a Heaviside history of tensile force and superimposed such loadings, i.e. staircase histories, and 2) the thinwalled spherical pressure vessel subject to a Heaviside history of internal pressure. For both these structures the conditions for instantaneous as well as delayed rupture are analysed. It is shown that a state of mechanical instability will be reached at a certain load or after a certain time. The cases of purely ductile rupture and purely brittle fracture are identified as two limiting cases of this general instability phenomenon. The Kachanov-Rabotnov damage law implies that a structural component will fail in tension only when it has reached a state of complete damage, i.e. zero load carrying capacity. The extended law predicts failure at an earlier stage of the deterioration process and is therefore more compatible with experimental observation. Further experimental support is offered by predictions for staircase loading histories, both step-up and step-down type. The presented damage theory here predicts strain histories which are in closer agreement with test data than predictions based on other phenomenological theories

  10. DNA Damage and Pulmonary Hypertension

    Science.gov (United States)

    Ranchoux, Benoît; Meloche, Jolyane; Paulin, Roxane; Boucherat, Olivier; Provencher, Steeve; Bonnet, Sébastien

    2016-01-01

    Pulmonary hypertension (PH) is defined by a mean pulmonary arterial pressure over 25 mmHg at rest and is diagnosed by right heart catheterization. Among the different groups of PH, pulmonary arterial hypertension (PAH) is characterized by a progressive obstruction of distal pulmonary arteries, related to endothelial cell dysfunction and vascular cell proliferation, which leads to an increased pulmonary vascular resistance, right ventricular hypertrophy, and right heart failure. Although the primary trigger of PAH remains unknown, oxidative stress and inflammation have been shown to play a key role in the development and progression of vascular remodeling. These factors are known to increase DNA damage that might favor the emergence of the proliferative and apoptosis-resistant phenotype observed in PAH vascular cells. High levels of DNA damage were reported to occur in PAH lungs and remodeled arteries as well as in animal models of PH. Moreover, recent studies have demonstrated that impaired DNA-response mechanisms may lead to an increased mutagen sensitivity in PAH patients. Finally, PAH was linked with decreased breast cancer 1 protein (BRCA1) and DNA topoisomerase 2-binding protein 1 (TopBP1) expression, both involved in maintaining genome integrity. This review aims to provide an overview of recent evidence of DNA damage and DNA repair deficiency and their implication in PAH pathogenesis. PMID:27338373

  11. Database of average-power damage thresholds at 1064 nm

    International Nuclear Information System (INIS)

    Rainer, F.; Hildum, E.A.; Milam, D.

    1987-01-01

    We have completed a database of average-power, laser-induced, damage thresholds at 1064 nm on a variety of materials. Measurements were made with a newly constructed laser to provide design input for moderate and high average-power laser projects. The measurements were conducted with 16-ns pulses at pulse-repetition frequencies ranging from 6 to 120 Hz. Samples were typically irradiated for time ranging from a fraction of a second up to 5 minutes (36,000 shots). We tested seven categories of samples which included antireflective coatings, high reflectors, polarizers, single and multiple layers of the same material, bare and overcoated metal surfaces, bare polished surfaces, and bulk materials. The measured damage threshold ranged from 2 for some metals to > 46 J/cm 2 for a bare polished glass substrate. 4 refs., 7 figs., 1 tab

  12. Damage and fatigue crack growth of Eurofer steel first wall mock-up under cyclic heat flux loads. Part 2: Finite element analysis of damage evolution

    International Nuclear Information System (INIS)

    You, Jeong-Ha

    2014-01-01

    Highlights: • The surface heat flux load of 3.5 MW/m 2 produced substantial stresses and inelastic strains in the heat-loaded surface region, especially at the notch root. • The notch root exhibited a typical notch effect such as stress concentration and localized inelastic yield leading to a preferred damage development. • The predicted damage evolution feature agrees well with the experimental observation. • The smooth surface also experiences considerable stresses and inelastic strains. However, the stress intensity and the amount of inelastic deformation are not high enough to cause any serious damage. • The level of maximum inelastic strain is higher at the notch root than at the smooth surface. On the other hand, the amplitude of inelastic strain variation is comparable at both positions. • The amount of inelastic deformation is significantly affected by the length of pulse duration time indicating the important role of creep. - Abstract: In the preceding companion article (part 1), the experimental results of the high-heat-flux (3.5 MW/m 2 ) fatigue tests of a Eurofer bare steel first wall mock-up was presented. The aim was to investigate the damage evolution and crack initiation feature. The mock-up used there was a simplified model having only basic and generic structural feature of an actively cooled steel FW component for DEMO reactor. In that study, it was found that microscopic damage was formed at the notch root already in the early stage of the fatigue loading. On the contrary, the heat-loaded smooth surface exhibited no damage up to 800 load cycles. In this paper, the high-heat-flux fatigue behavior is investigated with a finite element analysis to provide a theoretical interpretation. The thermal fatigue test was simulated using the coupled damage-viscoplastic constitutive model developed by Aktaa. The stresses, inelastic deformation and damage evolution at the notch groove and at the smooth surface are compared. The different damage

  13. Compression of thick laminated composite beams with initial impact-like damage

    Science.gov (United States)

    Breivik, N. L.; Guerdal, Z.; Griffin, O. H., Jr.

    1992-01-01

    While the study of compression after impact of laminated composites has been under consideration for many years, the complexity of the damage initiated by low velocity impact has not lent itself to simple predictive models for compression strength. The damage modes due to non-penetrating, low velocity impact by large diameter objects can be simulated using quasi-static three-point bending. The resulting damage modes are less coupled and more easily characterized than actual impact damage modes. This study includes the compression testing of specimens with well documented initial damage states obtained from three-point bend testing. Compression strengths and failure modes were obtained for quasi-isotropic stacking sequences from 0.24 to 1.1 inches thick with both grouped and interspersed ply stacking. Initial damage prior to compression testing was divided into four classifications based on the type, extent, and location of the damage. These classifications are multiple through-thickness delaminations, isolated delamination, damage near the surface, and matrix cracks. Specimens from each classification were compared to specimens tested without initial damage in order to determine the effects of the initial damage on the final compression strength and failure modes. A finite element analysis was used to aid in the understanding and explanation of the experimental results.

  14. Case Study of Local Damage Indicators for a 2-Bay, 6-Storey RC-Frame subject to Earthquakes

    DEFF Research Database (Denmark)

    Skjærbæk, P. S.; Nielsen, Søren R. K.; Kirkegaard, Poul Henning

    1997-01-01

    A simulation study of a 2-bay, 6storey model test RC-frame(scale 1:5) subject to earthquakes is considered in this paper. Based on measured (simulated) storey accelerations and ground surface accelerations several indices for the storey damage, including interstorey drift, flexural damage ratios......, normalized cumulative dissipated energy, Park and Ang's indicator, a low-cycle fatigue damage index and a recently proposed local softening damage index estimated from time-varying eigenfrequencies are used to evaluate the damage state of the structure after the earthquake. Storey displacements are obtained...

  15. Case Study of Local Damage Indicators for a 2-Bay, 6-Storey RC-Frame subject to Earthquakes

    DEFF Research Database (Denmark)

    Skjærbæk, P. S.; Nielsen, Søren R. K.; Kirkegaard, Poul Henning

    A simulation study of a 2-bay, 6storey model test RC-frame(scale 1:5) subject to earthquakes is considered in this paper. Based on measured (simulated) storey accelerations and ground surface accelerations several indices for the storey damage, including interstorey drift, flexural damage ratios......, normalized cumulative dissipated energy, Park and Ang's indicator, a low-cycle fatigue damage index and a recently proposed local softening damage index estimated from time-varying eigenfrequencies are used to evaluate the damage state of the structure after the earthquake. Storey displacements are obtained...

  16. Modeling damage in concrete pavements and bridges.

    Science.gov (United States)

    2010-09-01

    This project focused on micromechanical modeling of damage in concrete under general, multi-axial loading. A : continuum-level, three-dimensional constitutive model based on micromechanics was developed. The model : accounts for damage in concrete by...

  17. Nerve damage from diabetes - self-care

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000326.htm Nerve damage from diabetes - self-care To use the ... or at other unusual times. Treating and Preventing Nerve Damage from Diabetes Treating diabetic neuropathy can make ...

  18. Damage Models for Soft Tissues: A Survey.

    Science.gov (United States)

    Li, Wenguang

    Damage to soft tissues in the human body has been investigated for applications in healthcare, sports, and biomedical engineering. This paper reviews and classifies damage models for soft tissues to summarize achievements, identify new directions, and facilitate finite element analysis. The main ideas of damage modeling methods are illustrated and interpreted. A few key issues related to damage models, such as experimental data curve-fitting, computational effort, connection between damage and fractures/cracks, damage model applications, and fracture/crack extension simulation, are discussed. Several new challenges in the field are identified and outlined. This review can be useful for developing more advanced damage models and extending damage modeling methods to a variety of soft tissues.

  19. Effective elastic properties of damaged isotropic solids

    International Nuclear Information System (INIS)

    Lee, U Sik

    1998-01-01

    In continuum damage mechanics, damaged solids have been represented by the effective elastic stiffness into which local damage is smoothly smeared. Similarly, damaged solids may be represented in terms of effective elastic compliances. By virtue of the effective elastic compliance representation, it may become easier to derive the effective engineering constants of damaged solids from the effective elastic compliances, all in closed form. Thus, in this paper, by using a continuum modeling approach based on both the principle of strain energy equivalence and the equivalent elliptical micro-crack representation of local damage, the effective elastic compliance and effective engineering constants are derived in terms of the undamaged (virgin) elastic properties and a scalar damage variable for both damaged two-and three-dimensional isotropic solids

  20. Quantification of thermal damage in skin tissue

    Institute of Scientific and Technical Information of China (English)

    徐峰; 文婷; 卢天健; Seffen; Keith

    2008-01-01

    Skin thermal damage or skin burns are the most commonly encountered type of trauma in civilian and military communities. Besides, advances in laser, microwave and similar technologies have led to recent developments of thermal treatments for disease and damage involving skin tissue, where the objective is to induce thermal damage precisely within targeted tissue structures but without affecting the surrounding, healthy tissue. Further, extended pain sensation induced by thermal damage has also brought great...

  1. Large area damage testing of optics

    International Nuclear Information System (INIS)

    Sheehan, L.; Kozlowski, M.; Stolz, C.

    1996-01-01

    The damage threshold specifications for the National Ignition Facility will include a mixture of standard small-area tests and new large-area tests. During our studies of laser damage and conditioning processes of various materials we have found that some damage morphologies are fairly small and this damage does not grow with further illumination. This type of damage might not be detrimental to the laser performance. We should therefore assume that some damage can be allowed on the optics, but decide on a maximum damage allowance of damage. A new specification of damage threshold termed open-quotes functional damage thresholdclose quotes was derived. Further correlation of damage size and type to system performance must be determined in order to use this measurement, but it is clear that it will be a large factor in the optics performance specifications. Large-area tests have verified that small-area testing is not always sufficient when the optic in question has defect-initiated damage. This was evident for example on sputtered polarizer and mirror coatings where the defect density was low enough that the features could be missed by standard small- area testing. For some materials, the scale-length at which damage non-uniformities occur will effect the comparison of small-area and large-area tests. An example of this was the sub-aperture tests on KD*P crystals on the Beamlet test station. The tests verified the large-area damage threshold to be similar to that found when testing a small-area. Implying that for this KD*P material, the dominate damage mechanism is of sufficiently small scale-length that small-area testing is capable of determining the threshold. The Beamlet test station experiments also demonstrated the use of on-line laser conditioning to increase the crystals damage threshold

  2. Structural Health Monitoring for Impact Damage in Composite Structures.

    Energy Technology Data Exchange (ETDEWEB)

    Roach, Dennis P.; Raymond Bond (Purdue); Doug Adams (Purdue)

    2014-08-01

    Composite structures are increasing in prevalence throughout the aerospace, wind, defense, and transportation industries, but the many advantages of these materials come with unique challenges, particularly in inspecting and repairing these structures. Because composites of- ten undergo sub-surface damage mechanisms which compromise the structure without a clear visual indication, inspection of these components is critical to safely deploying composite re- placements to traditionally metallic structures. Impact damage to composites presents one of the most signi fi cant challenges because the area which is vulnerable to impact damage is generally large and sometimes very dif fi cult to access. This work seeks to further evolve iden- ti fi cation technology by developing a system which can detect the impact load location and magnitude in real time, while giving an assessment of the con fi dence in that estimate. Fur- thermore, we identify ways by which impact damage could be more effectively identi fi ed by leveraging impact load identi fi cation information to better characterize damage. The impact load identi fi cation algorithm was applied to a commercial scale wind turbine blade, and results show the capability to detect impact magnitude and location using a single accelerometer, re- gardless of sensor location. A technique for better evaluating the uncertainty of the impact estimates was developed by quantifying how well the impact force estimate meets the assump- tions underlying the force estimation technique. This uncertainty quanti fi cation technique was found to reduce the 95% con fi dence interval by more than a factor of two for impact force estimates showing the least uncertainty, and widening the 95% con fi dence interval by a fac- tor of two for the most uncertain force estimates, avoiding the possibility of understating the uncertainty associated with these estimates. Linear vibration based damage detection tech- niques were investigated in the

  3. Percutaneous penetration through slightly damaged skin

    DEFF Research Database (Denmark)

    Nielsen, Jesper B

    2005-01-01

    with human skin. A slight damage to the barrier integrity was induced by pre-treatment of the skin with sodium lauryl sulphate (SLS) before pesticide exposure. The experimental model with 3 h pre-treatment with SLS (0.1% or 0.3%) assured a significant but controlled damage to the barrier integrity, a damage...

  4. Damage Evaluation of Concrete Column under Impact Load Using a Piezoelectric-Based EMI Technique.

    Science.gov (United States)

    Fan, Shuli; Zhao, Shaoyu; Qi, Baoxin; Kong, Qingzhao

    2018-05-17

    One of the major causes of damage to column-supported concrete structures, such as bridges and highways, are collisions from moving vehicles, such as cars and ships. It is essential to quantify the collision damage of the column so that appropriate actions can be taken to prevent catastrophic events. A widely used method to assess structural damage is through the root-mean-square deviation (RMSD) damage index established by the collected data; however, the RMSD index does not truly provide quantitative information about the structure. Conversely, the damage volume ratio that can only be obtained via simulation provides better detail about the level of damage in a structure. Furthermore, as simulation can also provide the RMSD index relating to that particular damage volume ratio, the empirically obtained RMSD index can thus be related to the structural damage degree through comparison of the empirically obtained RMSD index to numerically-obtained RMSD. Thus, this paper presents a novel method in which the impact-induced damage to a structure is simulated in order to obtain the relationship between the damage volume ratio to the RMSD index, and the relationship can be used to predict the true damage degree by comparison to the empirical RMSD index. In this paper, the collision damage of a bridge column by moving vehicles was simulated by using a concrete beam model subjected to continuous impact loadings by a freefalling steel ball. The variation in admittance signals measured by the surface attached lead zirconate titanate (PZT) patches was used to establish the RMSD index. The results demonstrate that the RMSD index and the damage ratio of concrete have a linear relationship for the particular simulation model.

  5. Multi-physics modeling of multifunctional composite materials for damage detection

    Science.gov (United States)

    Sujidkul, Thanyawalai

    This study presents a modeling of multifunction composite materials for damage detection with its verification and validation to mechanical behavior predictions of Carbon Fibre Reinforced Polymer composites (CFRPs), CFRPs laminated composites, and woven SiC/SiC matrix composites that are subjected to fracture damage. Advantages of those materials are low cost, low density, high strength-to-weight ratio, and comparable specific tensile properties, the special of SiC/SiC is good environmental stability at high temperature. Resulting in, the composite has been used for many important structures such as helicopter rotors, aerojet engines, gas turbines, hot control surfaces, sporting goods, and windmill blades. Damage or material defect detection in a mechanical component can provide vital information for the prediction of remaining useful life, which will result in the prevention of catastrophic failures. Thus the understanding of the mechanical behavior have been challenge to the prevent damage and failure of composites in different scales. The damage detection methods in composites have been investigated widely in recent years. Non-destructive techniques are the traditional methods to detect the damage such as X-ray, acoustic emission and thermography. However, due to the invisible damage in composite can be occurred, to prevent the failure in composites. The developments of damage detection methods have been considered. Due to carbon fibers are conductive materials, in resulting CFRPs can be self-sensing to detect damage. As is well known, the electrical resistance has been shown to be a sensitive measure of internal damage, and also this work study in thermal resistance can detect damage in composites. However, there is a few number of different micromechanical modeling schemes has been proposed in the published literature for various types of composites. This works will provide with a numerical, analytical, and theoretical failure models in different damages to

  6. Radiation damage in lithium orthosilicate

    Energy Technology Data Exchange (ETDEWEB)

    Noda, K.; Nakazawa, T.; Ishii, Y.; Fukai, K.; Watanabe, H. (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment); Matsui, H.; Vollath, D.

    1993-11-01

    Radiation damage in lithium orthosilicate (Li[sub 4]SiO[sub 4]) and Al-doped Li[sub 4]SiO[sub 4] (Li[sub 3.7]Al[sub 0.1]SiO[sub 4]) irradiated with oxygen ions was studied with ionic conductivity measurements, Raman spectroscopy, Fourier transform infrared photo-acoustic spectroscopy (FT-IR PAS) and transmission electron microscopy. It was seen from the ionic conductivity measurements that lithium-ion vacancies were introduced as irradiation defects for Li-ions sites in both materials due to the irradiation. By the Raman spectroscopy, oxygen atoms in SiO[sub 4] tetrahedra were considered to be preferentially displaced due to the irradiation for Li[sub 4]SiO[sub 4], although only a decrease of the number of SiO[sub 4] tetrahedra occurred for Li[sub 3.7]Al[sub 0.1]SiO[sub 4] by displacement of both silicon and oxygen atoms. Decomposition of SiO[sub 4] tetrahedra and formation of some new phases having Si-O-Si and Si-O bonds were found to take place for both Li[sub 4]SiO[sub 4] and Li[sub 3.7]Al[sub 0.1]SiO[sub 4] by FT-IR PAS. In the electron microscopy, damage microstructure consisting of many voids or cavities and amorphization were observed for Li[sub 4]SiO[sub 4] irradiated with oxygen ions. The recovery behavior of radiation damage mentioned above was also investigated. (author).

  7. Damage instability and Earthquake nucleation

    Science.gov (United States)

    Ionescu, I. R.; Gomez, Q.; Campillo, M.; Jia, X.

    2017-12-01

    Earthquake nucleation (initiation) is usually associated to the loss of the stability of the geological structure under a slip-weakening friction acting on the fault. The key parameters involved in the stability of the fault are the stress drop, the critical slip distance but also the elastic stiffness of the surrounding materials (rocks). We want to explore here how the nucleation phenomena are correlated to the material softening during damage accumulation by dynamic and/or quasi-static processes. Since damage models are describing micro-cracks growth, which is generally an unstable phenomenon, it is natural to expect some loss of stability on the associated micro-mechanics based models. If the model accurately captures the material behavior, then this can be due to the unstable nature of the brittle material itself. We obtained stability criteria at the microscopic scale, which are related to a large class of damage models. We show that for a given continuous strain history the quasi-static or dynamic problems are instable or ill-posed (multiplicity of material responses) and whatever the selection rule is adopted, shocks (time discontinuities) will occur. We show that the quasi-static equilibria chosen by the "perfect delay convention" is always stable. These stability criteria are used to analyze how NIC (Non Interacting Crack) effective elasticity associated to "self similar growth" model work in some special configurations (one family of micro-cracks in mode I, II and III and in plane strain or plain stress). In each case we determine a critical crack density parameter and critical micro-crack radius (length) which distinguish between stable and unstable behaviors. This critical crack density depends only on the chosen configuration and on the Poisson ratio.

  8. Lack of correlation between villus and crypt damage in irradiated mouse intestine

    International Nuclear Information System (INIS)

    Carr, K.E.; Hamlet, R.; Nias, A.H.W.; Watt, C.

    1979-01-01

    It has been observed that scanning electron microscopy is a more sensitive indicator of mucosal damage at low radiation dose levels than conventional quantitative crypt counting techniques. Three different fractionation schedules were subjected to investigation by both of these methods to try and elucidate some features of irradiation damage to the whole of the intestinal mucosa, at dose levels commonly used in clinical practice. Despite variations in the qualitative observations, there was a marked difference in two of the schedules between damage expressed as crypt counts and that described by the qualitative techniques. In the first case high crypt numbers were associated with severe mucosal damage, whereas the second schedule produced a reduced crypt count in association with low damage to the surface mucosa. A third schedule produced results in which there was a general agreement between low crypt numbers and considerable surface mucosal damage. However, observations were made of mucosal formations not previously seen on damaged mucosa; surfaces. These resembled the appearance normally associated with the gut of patients suffering from coeliac disease. Variations in the qualitative observations were seen in the schedules so that their interpretation in terms of perturbation of cellular kinetics is difficult. (author)

  9. Radiation damage of structural materials

    CERN Document Server

    Koutsky, Jaroslav

    1994-01-01

    Maintaining the integrity of nuclear power plants is critical in the prevention or control of severe accidents. This monograph deals with both basic groups of structural materials used in the design of light-water nuclear reactors, making the primary safety barriers of NPPs. Emphasis is placed on materials used in VVER-type nuclear reactors: Cr-Mo-V and Cr-Ni-Mo-V steel for RPV and Zr-Nb alloys for fuel element cladding. The book is divided into 7 main chapters, with the exception of the opening one and the chapter providing a phenomenological background for the subject of radiation damage. Ch

  10. Radiation damage in silicon detectors

    CERN Document Server

    Lindström, G

    2003-01-01

    Radiation damage effects in silicon detectors under severe hadron and gamma-irradiation are surveyed, focusing on bulk effects. Both macroscopic detector properties (reverse current, depletion voltage and charge collection) as also the underlying microscopic defect generation are covered. Basic results are taken from the work done in the CERN-RD48 (ROSE) collaboration updated by results of recent work. Preliminary studies on the use of dimerized float zone and Czochralski silicon as detector material show possible benefits. An essential progress in the understanding of the radiation-induced detector deterioration had recently been achieved in gamma irradiation, directly correlating defect analysis data with the macroscopic detector performance.

  11. The ischemic perinatal brain damage

    International Nuclear Information System (INIS)

    Crisi, G.; Mauri, C.; Canossi, G.; Della Giustina, E.

    1986-01-01

    The term ''hypoxic-ischemic encephalopathy'' covers a large part of neonatal neuropathology including the various forms of intracerebral haemorrhage. In the present work the term is confined to ischemic brain edema and actual infarction, be it diffuse or focal. Eighteen newborns with CT evidence of ischemic brain lesions and infarctual necrosis were selected. Emphasis is placed on current data on neuropathology of ischemic brain edema and its CT appearance. Particular entities such as periventricular leukomalacia and multicystic encephalopathy are discussed. Relationship between CT and temporal profile of cerebral damage is emphasized in order to predict the structural sequelae and the longterm prognosis

  12. Damages by radiation in glasses

    International Nuclear Information System (INIS)

    Olguin, F.; Gutierrez, C.; Cisniega, G.; Flores, J.H.; Golzarri, J.I.; Espinoza, G.

    1997-01-01

    As a part of the works carried out to characterize the electrons beam from the Pelletron accelerator of the Mexican Nuclear Center aluminium-silicate glass samples were irradiated. The purpose of these irradiations is to cause alterations in the amorphous microstructure of the material by means of the creation of color centers. The population density of these defects, consequence to the irradiation, is function of the exposure time which varied from 1 to 30 minutes, with an electronic beam energy of 400 keV, doing the irradiations at free atmosphere. the obtained spectra are correlated by damage which the radiation produced. (Author)

  13. Air pollution damage to plants

    Energy Technology Data Exchange (ETDEWEB)

    Daly, G T

    1974-01-01

    The effects of the most important air pollutants on plants are described in detail. The include: smoke and particulates, sulfur dioxide, fluorides, peroxyacetyl nitrate, nitrogen oxides, and ozone. An attempt is made to show that plant injury by air pollution can be recognized and evaluated in the presence of effects from insect, fungal, bacterial, viral pathogens and the symptoms of nutrient and enviromental stress. All plants are more or less affected by toxic gases and metals absorbed from the air. For each plant and each pollutant there is a critical concentration above which damage occurs, and below which growth is normal.

  14. Structural damage and chemical contaminants on reprocessed arthroscopic shaver blades.

    Science.gov (United States)

    Kobayashi, Masahiko; Nakagawa, Yasuaki; Okamoto, Yukihiro; Nakamura, Shinichiro; Nakamura, Takashi

    2009-02-01

    In response to socioeconomic pressure to cut budgets in medicine, single-use surgical instruments are often reprocessed despite potential biological hazard. To evaluate the quality and contaminants of reprocessed shaver blades. Reprocessed shaver blades have mechanical damage and chemical contamination. Controlled laboratory study. Seven blades and 3 abraders were reprocessed 1 time or 3 times and then were assessed. In the first part of the study, structural damage on the blades after 3 reprocessings was compared to that after 1 reprocessing using optical microscopy. In the second part, surface damage was observed using optical microscopy and scanning electron microscopy; elemental and chemical analyses of contaminants found by the microscopy were performed using scanning electron microscopy/energy dispersive x-ray spectroscopy, scanning Auger microscopy, and Fourier transform infrared spectroscopy. Optical microscopic examination revealed abrasion on the surface of the inner blade and cracks on the inner tube after 1 reprocessing. These changes were more evident after 3 reprocessings. Scanning electron microscopy/energy dispersive x-ray spectroscopy of the inner cutter of the blade reprocessed once showed contaminants containing calcium, carbon, oxygen, and silicon, and Fourier transform infrared spectroscopy demonstrated biological protein consisting mainly of collagen, some type of salts, and polycarbonate used in plastic molding. Scanning electron microscopy/energy dispersive x-ray spectroscopy of the inner cutter of the reprocessed abrader revealed contaminants containing carbon, calcium, phosphorous, and oxygen, and Fourier transform infrared spectroscopy showed H2O, hydroxyapatite, and hydroxyl proteins. Scanning Auger microscopy showed that the tin-nickel plating on the moving blade and abrader was missing in some locations. This is the first study to evaluate both mechanical damage and chemical contaminants containing collagen, hydroxyapatite, and salts

  15. Surface contact fatigue failures in gears

    CSIR Research Space (South Africa)

    Fernandes, PJL

    1997-06-01

    Full Text Available Surface contact fatigue is the most common cause of gear failure. It results in damage to contacting surfaces which can significantly reduce the load-carrying capacity of components, and may ultimately lead to complete failure of a gear. Three types...

  16. Minimal surfaces

    CERN Document Server

    Dierkes, Ulrich; Sauvigny, Friedrich; Jakob, Ruben; Kuster, Albrecht

    2010-01-01

    Minimal Surfaces is the first volume of a three volume treatise on minimal surfaces (Grundlehren Nr. 339-341). Each volume can be read and studied independently of the others. The central theme is boundary value problems for minimal surfaces. The treatise is a substantially revised and extended version of the monograph Minimal Surfaces I, II (Grundlehren Nr. 295 & 296). The first volume begins with an exposition of basic ideas of the theory of surfaces in three-dimensional Euclidean space, followed by an introduction of minimal surfaces as stationary points of area, or equivalently

  17. Damage Detection of a Concrete Column Subject to Blast Loads Using Embedded Piezoceramic Transducers.

    Science.gov (United States)

    Xu, Kai; Deng, Qingshan; Cai, Lujun; Ho, Siuchun; Song, Gangbing

    2018-04-28

    Some of the most severe structural loadings come in the form of blast loads, which may be caused by severe accidents or even terrorist activities. Most commonly after exposure to explosive forces, a structure will suffer from different degrees of damage, and even progress towards a state of collapse. Therefore, damage detection of a structure subject to explosive loads is of importance. This paper proposes a new approach to damage detection of a concrete column structure subjected to blast loads using embedded piezoceramic smart aggregates (SAs). Since the sensors are embedded in the structure, the proposed active-sensing based approach is more sensitive to internal or through cracks than surface damage. In the active sensing approach, the embedded SAs act as actuators and sensors, that can respectively generate and detect stress waves. If the stress wave propagates across a crack, the energy of the wave attenuates, and the reduction of the energy compared to the healthy baseline is indicative of a damage. With a damage index matrix constructed by signals obtained from an array of SAs, cracks caused by blast loads can be detected throughout the structure. Conventional sensing methods such as the measurement of dynamic strain and acceleration were included in the experiment. Since columns are critical elements needed to prevent structural collapse, knowledge of their integrity and damage conditions is essential for safety after exposure to blast loads. In this research, a concrete column with embedded SAs was chosen as the specimen, and a series of explosive tests were conducted on the column. Experimental results reveal that surface damages, though appear severe, cause minor changes in the damage index, and through cracks result in significant increase of the damage index, demonstrating the effectiveness of the active sensing, enabled by embedded SAs, in damage monitoring of the column under blast loads, and thus providing a reliable indication of structural

  18. Focused ion beam damage to MOS integrated circuits

    International Nuclear Information System (INIS)

    Fleetwood, D.M.; Campbell, Ann N.; Hembree, Charles E.; Tangyunyong, Paiboon; Jessing, Jeffrey R.; Soden, Jerry M.

    2000-01-01

    Commercial focused ion beam (FIB) systems are commonly used to image integrated circuits (ICS) after device processing, especially in failure analysis applications. FIB systems are also often employed to repair faults in metal lines for otherwise functioning ICS, and are being evaluated for applications in film deposition and nanofabrication. A problem that is often seen in FIB imaging and repair is that ICS can be damaged during the exposure process. This can result in degraded response or out-right circuit failure. Because FIB processes typically require the surface of an IC to be exposed to an intense beam of 30--50 keV Ga + ions, both charging and secondary radiation damage are potential concerns. In previous studies, both types of effects have been suggested as possible causes of device degradation, depending on the type of device examined and/or the bias conditions. Understanding the causes of this damage is important for ICS that are imaged or repaired by a FIB between manufacture and operation, since the performance and reliability of a given IC is otherwise at risk in subsequent system application. In this summary, the authors discuss the relative roles of radiation damage and charging effects during FIB imaging. Data from exposures of packaged parts under controlled bias indicate the possibility for secondary radiation damage during FIB exposure. On the other hand, FIB exposure of unbiased wafers (a more common application) typically results in damage caused by high-voltage stress or electrostatic discharge. Implications for FIB exposure and subsequent IC use are discussed

  19. Damage assessment in CFRP laminates exposed to impact fatigue loading

    International Nuclear Information System (INIS)

    Tsigkourakos, George; Silberschmidt, Vadim V; Ashcroft, I A

    2011-01-01

    Demand for advanced engineering composites in the aerospace industry is increasing continuously. Lately, carbon fibre reinforced polymers (CFRPs) became one of the most important structural materials in the industry due to a combination of characteristics such as: excellent stiffness, high strength-to-weight ratio, and ease of manufacture according to application. In service, aerospace composite components and structures are exposed to various transient loads, some of which can propagate in them as cyclic impacts. A typical example is an effect of the wind gusts during flight. This type of loading is known as impact fatigue (IF); it is a repetition of low-energy impacts. Such loads can cause various types of damage in composites: fibre breaking, transverse matrix cracking, de-bonding between fibres and matrix and delamination resulting in reduction of residual stiffness and loss of functionality. Furthermore, this damage is often sub-surface, which reinforces the need for more regular inspection. The effects of IF are of major importance due its detrimental effect on the structural integrity of components that can be generated after relatively few impacts at low force levels compared to those in a standard fatigue regime. This study utilises an innovative testing system with the capability of subjecting specimens to a series of repetitive impacts. The primary subject of this paper is to assess the damaging effect of IF on the behaviour of drilled CFRP specimens, exposed to such loading. A detailed damage analysis is implemented utilising an X-ray micro computed tomography system. The main findings suggested that at early stages of life damage is governed by o degree splits along the length of the specimens resulting in a 20% reduction of stiffness. The final failure damage scenario indicated that transverse crasks in the 90 degree plies are the main reason for complete delamination which can be translated to a 50% stiffness reduction.

  20. Structural and electrical characterization of HBr/O2 plasma damage to Si substrate

    International Nuclear Information System (INIS)

    Fukasawa, Masanaga; Nakakubo, Yoshinori; Matsuda, Asahiko; Takao, Yoshinori; Eriguchi, Koji; Ono, Kouichi; Minami, Masaki; Uesawa, Fumikatsu; Tatsumi, Tetsuya

    2011-01-01

    Silicon substrate damage caused by HBr/O 2 plasma exposure was investigated by spectroscopic ellipsometry (SE), high-resolution Rutherford backscattering spectroscopy, and transmission electron microscopy. The damage caused by H 2 , Ar, and O 2 plasma exposure was also compared to clarify the ion-species dependence. Although the damage basically consists of a surface oxidized layer and underlying dislocated Si, the damage structure strongly depends on the incident ion species, ion energy, and oxidation during air and plasma exposure. In the case of HBr/O 2 plasma exposure, hydrogen generated the deep damaged layer (∼10 nm), whereas ion-enhanced diffusion of oxygen, supplied simultaneously by the plasma, caused the thick surface oxidation. In-line monitoring of damage thicknesses by SE, developed with an optimized optical model, showed that the SE can be used to precisely monitor damage thicknesses in mass production. Capacitance-voltage (C-V) characteristics of a damaged layer were studied before and after diluted-HF (DHF) treatment. Results showed that a positive charge is generated at the surface oxide-dislocated Si interface and/or in the bulk oxide after plasma exposure. After DHF treatment, most of the positive charges were removed, while the thickness of the ''Si recess'' was increased by removing the thick surface oxidized layer. As both the Si recess and remaining dislocated Si, including positive charges, cause the degradation of electrical performance, precise monitoring of the surface structure and understanding its effect on device performance is indispensable for creating advanced devices.

  1. Structural and electrical characterization of HBr/O{sub 2} plasma damage to Si substrate

    Energy Technology Data Exchange (ETDEWEB)

    Fukasawa, Masanaga; Nakakubo, Yoshinori; Matsuda, Asahiko; Takao, Yoshinori; Eriguchi, Koji; Ono, Kouichi; Minami, Masaki; Uesawa, Fumikatsu; Tatsumi, Tetsuya [Semiconductor Technology Development Division, Semiconductor Business Group, Professional, Device and Solutions Group, Sony Corporation, 4-14-1 Asahi-cho, Atsugi-shi, Kanagawa 243-0014 (Japan); Department of Aeronautics and Astronautics, Graduate School of Engineering, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Semiconductor Technology Development Division, Semiconductor Business Group, Professional, Device and Solutions Group, Sony Corporation, 4-14-1 Asahi-cho, Atsugi-shi, Kanagawa 243-0014 (Japan)

    2011-07-15

    Silicon substrate damage caused by HBr/O{sub 2} plasma exposure was investigated by spectroscopic ellipsometry (SE), high-resolution Rutherford backscattering spectroscopy, and transmission electron microscopy. The damage caused by H{sub 2}, Ar, and O{sub 2} plasma exposure was also compared to clarify the ion-species dependence. Although the damage basically consists of a surface oxidized layer and underlying dislocated Si, the damage structure strongly depends on the incident ion species, ion energy, and oxidation during air and plasma exposure. In the case of HBr/O{sub 2} plasma exposure, hydrogen generated the deep damaged layer ({approx}10 nm), whereas ion-enhanced diffusion of oxygen, supplied simultaneously by the plasma, caused the thick surface oxidation. In-line monitoring of damage thicknesses by SE, developed with an optimized optical model, showed that the SE can be used to precisely monitor damage thicknesses in mass production. Capacitance-voltage (C-V) characteristics of a damaged layer were studied before and after diluted-HF (DHF) treatment. Results showed that a positive charge is generated at the surface oxide-dislocated Si interface and/or in the bulk oxide after plasma exposure. After DHF treatment, most of the positive charges were removed, while the thickness of the ''Si recess'' was increased by removing the thick surface oxidized layer. As both the Si recess and remaining dislocated Si, including positive charges, cause the degradation of electrical performance, precise monitoring of the surface structure and understanding its effect on device performance is indispensable for creating advanced devices.

  2. Low cycle fatigue: high cycle fatigue damage accumulation in a 304L austenitic stainless steel

    International Nuclear Information System (INIS)

    Lehericy, Y.

    2007-05-01

    The aim of this study was to evaluate the consequences of a Low Cycle Fatigue pre-damage on the subsequent fatigue limit of a 304L stainless steel. The effects of hardening and severe roughness (grinding) have also been investigated. In a first set of tests, the evolution of the surface damage induced by the different LCF pre-cycling was characterized. This has permitted to identify mechanisms and kinetics of damage in the plastic domain for different surface conditions. Then, pre-damaged samples were tested in the High Cycle Fatigue domain in order to establish the fatigue limits associated with each level of pre-damage. Results evidence that, in the case of polished samples, an important number of cycles is required to initiate surface cracks ant then to affect the fatigue limit of the material but, in the case of ground samples, a few number of cycles is sufficient to initiate cracks and to critically decrease the fatigue limit. The fatigue limit of pre-damaged samples can be estimated using the stress intensity factor threshold. Moreover, this detrimental effect of severe surface conditions is enhanced when fatigue tests are performed under a positive mean stress (author)

  3. Non-destructive evaluation of UV pulse laser-induced damage performance of fused silica optics.

    Science.gov (United States)

    Huang, Jin; Wang, Fengrui; Liu, Hongjie; Geng, Feng; Jiang, Xiaodong; Sun, Laixi; Ye, Xin; Li, Qingzhi; Wu, Weidong; Zheng, Wanguo; Sun, Dunlu

    2017-11-24

    The surface laser damage performance of fused silica optics is related to the distribution of surface defects. In this study, we used chemical etching assisted by ultrasound and magnetorheological finishing to modify defect distribution in a fused silica surface, resulting in fused silica samples with different laser damage performance. Non-destructive test methods such as UV laser-induced fluorescence imaging and photo-thermal deflection were used to characterize the surface defects that contribute to the absorption of UV laser radiation. Our results indicate that the two methods can quantitatively distinguish differences in the distribution of absorptive defects in fused silica samples subjected to different post-processing steps. The percentage of fluorescence defects and the weak absorption coefficient were strongly related to the damage threshold and damage density of fused silica optics, as confirmed by the correlation curves built from statistical analysis of experimental data. The results show that non-destructive evaluation methods such as laser-induced fluorescence and photo-thermal absorption can be effectively applied to estimate the damage performance of fused silica optics at 351 nm pulse laser radiation. This indirect evaluation method is effective for laser damage performance assessment of fused silica optics prior to utilization.

  4. Shaped input distributions for structural damage localization

    DEFF Research Database (Denmark)

    Ulriksen, Martin Dalgaard; Bernal, Dionisio; Damkilde, Lars

    2018-01-01

    localization method is cast that operates on the premise of shaping inputs—whose spatial distribution is fixed—by use of a model, such that these inputs, in one structural subdomain at a time, suppress certain steady-state vibration quantities (depending on the type of damage one seeks to interrogate for......). Accordingly, damage is localized when the vibration signature induced by the shaped inputs in the damaged state corresponds to that in the reference state, hereby implying that the approach does not point directly to damage. Instead, it operates with interrogation based on postulated damage patterns...

  5. Air pollution and brain damage.

    Science.gov (United States)

    Calderón-Garcidueñas, Lilian; Azzarelli, Biagio; Acuna, Hilda; Garcia, Raquel; Gambling, Todd M; Osnaya, Norma; Monroy, Sylvia; DEL Tizapantzi, Maria Rosario; Carson, Johnny L; Villarreal-Calderon, Anna; Rewcastle, Barry

    2002-01-01

    Exposure to complex mixtures of air pollutants produces inflammation in the upper and lower respiratory tract. Because the nasal cavity is a common portal of entry, respiratory and olfactory epithelia are vulnerable targets for toxicological damage. This study has evaluated, by light and electron microscopy and immunohistochemical expression of nuclear factor-kappa beta (NF-kappaB) and inducible nitric oxide synthase (iNOS), the olfactory and respiratory nasal mucosae, olfactory bulb, and cortical and subcortical structures from 32 healthy mongrel canine residents in Southwest Metropolitan Mexico City (SWMMC), a highly polluted urban region. Findings were compared to those in 8 dogs from Tlaxcala, a less polluted, control city. In SWMMC dogs, expression of nuclear neuronal NF-kappaB and iNOS in cortical endothelial cells occurred at ages 2 and 4 weeks; subsequent damage included alterations of the blood-brain barrier (BBB), degenerating cortical neurons, apoptotic glial white matter cells, deposition of apolipoprotein E (apoE)-positive lipid droplets in smooth muscle cells and pericytes, nonneuritic plaques, and neurofibrillary tangles. Persistent pulmonary inflammation and deteriorating olfactory and respiratory barriers may play a role in the neuropathology observed in the brains of these highly exposed canines. Neurodegenerative disorders such as Alzheimer's may begin early in life with air pollutants playing a crucial role.

  6. Ultrasonic wave damage detecting device

    International Nuclear Information System (INIS)

    Miura, Yuichi; Nagao, Tetsuya; Nishi, Yuji; Kubota, Keisuke; Maruyama, Takayuki.

    1994-01-01

    Upon detecting a damage for a joint between a connecting nozzle at the outer circumference of a reactor pressure vessel and pipelines, the present invention greatly shortens the operation time. That is, it is noted that the connecting nozzle has a tapered portion and a small-diameter portion in view of strength. A main magnetic wheel supported on a base of a running vehicle is attracted to the small-diameter portion and an auxiliary magnet wheel is attracted to the tapered portion respectively and they are rolled. This regulate the deviation of the position of the base of the running vehicle in axial direction of the nozzle by the small-diameter portion and the tapered portion. Accordingly, the running vehicle can be circulated along a predetermined course on the outer circumference of the connecting nozzle without using tracks such as an existent ring track. The test can be performed conveniently only by placing the damage detecting device on the connecting nozzle. As a result, preparation time required before the test can remarkably be shortened. (I.S.)

  7. DNA damage repair and radiosensitivity

    International Nuclear Information System (INIS)

    Suzuki, Norio

    2003-01-01

    Tailored treatment is not new in radiotherapy; it has been the major subject for the last 20-30 years. Radiation responses and RBE (relative biological effectiveness) depend on assay systems, endpoints, type of tissues and tumors, radiation quality, dose rate, dose fractionation, physiological and environmental factors etc, Latent times to develop damages also differ among tissues and endpoints depending on doses and radiation quality. Recent progress in clarification of radiation induced cell death, especially of apoptotic cell death, is quite important for understanding radiosensitivity of tumor cure process as well as of tumorigenesis. Apoptotic cell death as well as dormant cells had been unaccounted and missed into a part of reproductive cell death. Another area of major progress has been made in clarifying repair mechanisms of radiation damage, i.e., non-homologous end joining (NHEJ) and homologous recombinational repair (HRR). New approaches and developments such as cDNA or protein micro arrays and so called informatics in addition to basic molecular biological analysis are expected to aid identifying molecules and their roles in signal transduction pathways, which are multi-factorial and interactive each other being involved in radiation responses. (authors)

  8. Rumble surfaces

    CSIR Research Space (South Africa)

    National Institute for Transport and Road

    1977-01-01

    Full Text Available Rumble surfaces are intermittent short lengths of coarse-textured road surfacings on which vehicle tyres produce a rumbling sound. used in conjunction with appropriate roadsigns and markings, they can reduce accidents on rural roads by alerting...

  9. Earthquake damage to underground facilities and earthquake related displacement fields

    International Nuclear Information System (INIS)

    Pratt, H.R.; Stephenson, D.E.; Zandt, G.; Bouchon, M.; Hustrulid, W.A.

    1982-01-01

    The potential seismic risk for an underground facility is considered in the evaluation of its location and design. The possible damage resulting from either large-scale displacements or high accelerations should be considered in evaluating potential sites of underground facilities. Scattered through the available literature are statements to the effect that below a few hundred meters shaking and damage in mines is less than at the surface; however, data for decreased damage underground have not been completely reported or explained. In order to assess the seismic risk for an underground facility, a data base was established and analyzed to evaluate the potential for seismic disturbance. Substantial damage to underground facilities is usually the result of displacements primarily along pre-existing faults and fractures, or at the surface entrance to these facilities. Evidence of this comes from both earthquakes as a function of depth is important in the evaluation of the hazard to underground facilities. To evaluate potential displacements due to seismic effects of block motions along pre-existing or induced fractures, the displacement fields surrounding two types of faults were investigated. Analytical models were used to determine relative displacements of shafts and near-surface displacement of large rock masses. Numerical methods were used to determine the displacement fields associated with pure strike-slip and vertical normal faults. Results are presented as displacements for various fault lengths as a function of depth and distance. This provides input to determine potential displacements in terms of depth and distance for underground facilities, important for assessing potential sites and design parameters

  10. A measure of vulnerability and damage tolerance

    International Nuclear Information System (INIS)

    Lind, Niels C.

    1995-01-01

    The purpose of the paper is to present probabilistic definitions of 'vulnerability' and 'damage tolerance'. A new measure of damage is also proposed. Disastrous failures, such as of the Titanic or the Chernobyl reactor, have revealed that some systems can be highly vulnerable. A seemingly insignificant damage can reduce such a system's resistance severely. Attempts to write design code requirements for damage tolerance or structural integrity have not been successful so far. One reason is that these ideas have not been defined with the necessary precision. The suggested definitions aim to be general, applicable to all engineered systems, and readily specializable to particular system types. Vulnerability is defined as the ratio of the failure probability of the damaged system to the failure probability of the undamaged system. It is argued that 'vulnerability' and 'damage tolerance' are complementary concepts. Damage tolerance is defined as the reciprocal of vulnerability. Vulnerability and damage tolerance both concern hypothetical future damage. A damage factor, applicable for the analysis of an existing structure in an assessed state of damage, is defined analogous to vulnerability. Application is illustrated by examples

  11. Surface thermodynamics

    International Nuclear Information System (INIS)

    Garcia-Moliner, F.

    1975-01-01

    Basic thermodynamics of a system consisting of two bulk phases with an interface. Solid surfaces: general. Discussion of experimental data on surface tension and related concepts. Adsorption thermodynamics in the Gibbsian scheme. Adsorption on inert solid adsorbents. Systems with electrical charges: chemistry and thermodynamics of imperfect crystals. Thermodynamics of charged surfaces. Simple models of charge transfer chemisorption. Adsorption heat and related concepts. Surface phase transitions

  12. Beam damage of self-assembled monolayers

    International Nuclear Information System (INIS)

    Rieke, P.C.; Baer, D.R.; Fryxell, G.E.; Engelhard, M.H.; Porter, M.S.

    1993-01-01

    X-ray and electron beam damage studies were performed on Br-terminated and methyl-terminated alkylsilane self-assembled monolayers. X-ray beam initiated damage was primarily limited to removal of the labile Br group and did not significantly damage the hydrocarbon chain. Some of the x-ray beam damage could be attributed to low-energy electrons emitted by the non-monochromatic source, but further damage was attributed to secondary electrons produced in the sample by x-ray exposure. Electron beams caused significant damage to the hydrocarbon chains. Maximum damage occurred with a beam energy of 600 eV and a dosage of 6x10 -3 C/cm 2

  13. Damage Detection and Deteriorating Structural Systems

    DEFF Research Database (Denmark)

    Long, Lijia; Thöns, Sebastian; Döhler, Michael

    2017-01-01

    This paper addresses the quantification of the value of damage detection system and algorithm information on the basis of Value of Information (VoI) analysis to enhance the benefit of damage detection information by providing the basis for its optimization before it is performed and implemented....... The approach of the quantification the value of damage detection information builds upon the Bayesian decision theory facilitating the utilization of damage detection performance models, which describe the information and its precision on structural system level, facilitating actions to ensure the structural...... detection information is determined utilizing Bayesian updating. The damage detection performance is described with the probability of indication for different component and system damage states taking into account type 1 and type 2 errors. The value of damage detection information is then calculated...

  14. Nuclear damage compensation and energy reform

    International Nuclear Information System (INIS)

    Yokemoto, Masafumi

    2013-01-01

    Nuclear damage compensation and energy reform were closely related. Nuclear damage compensation cost should be part of generation cost of nuclear power. Extend of nuclear damage compensation was limited by compensation standard of Tokyo Electric Power Co. (TEPCO) following guidelines of Dispute Reconciliation Committee for Nuclear Damage Compensation. TEPCO had already paid compensation of about two trillion yen until now, which was only a part of total damage compensation cost. TEPCO had been provided more than 3.4 trillion yen by Nuclear Damage Liability Facilitation Cooperation, which would be put back by nuclear operators including TEPCO. TEPCO could obtain present raising funds and try to reconstruct business with restart of nuclear power, which might disturb energy reform. Present nuclear damage compensation scheme had better be reformed with learning more from Minamata disease case in Japan. (T. Tanaka)

  15. Wiring Damage Analyses for STS OV-103

    Science.gov (United States)

    Thomas, Walter, III

    2006-01-01

    This study investigated the Shuttle Program s belief that Space Transportation System (STS) wiring damage occurrences are random, that is, a constant occurrence rate. Using Problem Reporting and Corrective Action (PRACA)-derived data for STS Space Shuttle OV-103, wiring damage was observed to increase over the vehicle s life. Causal factors could include wiring physical deterioration, maintenance and inspection induced damage, and inspection process changes resulting in more damage events being reported. Induced damage effects cannot be resolved with existent data. Growth analysis (using Crow-AMSAA, or CA) resolved maintenance/inspection effects (e.g., heightened awareness) on all wire damages and indicated an overall increase since Challenger Return-to-Flight (RTF). An increasing failure or occurrence rate per flight cycle was seen for each wire damage mode; these (individual) rates were not affected by inspection process effects, within statistical error.

  16. Radiation damage in materials. Primary knock-on atom energy analyses of cascade damage

    International Nuclear Information System (INIS)

    Sekimura, Naoto

    1995-01-01

    To understand cascade damage formation as a function of primary recoil energy, thin foils of gold were irradiated with 20 - 400 keV self-ions to 1.0 x 10 14 ions/m 2 at 300 K. Yield of groups of vacancy clusters saturated at ion energy higher than 100 keV. Number of clusters in a group had variation even from the same energy ions. Size distribution of the clusters was not strongly dependent on number of clusters in a group and ion energy. Density of vacancy clusters in a group formed near the specimen surface was calibrated to estimate vacancy cluster formation in neutron-irradiated material. A model was proposed to predict distribution of defect clusters in the irradiated materials based on a primary recoil spectrum. Examples of recomposed distribution of vacancy clusters in a group in irradiated gold were compared with the measured data. (author)

  17. Automated Damage Onset Analysis Techniques Applied to KDP Damage and the Zeus Small Area Damage Test Facility

    International Nuclear Information System (INIS)

    Sharp, R.; Runkel, M.

    1999-01-01

    Automated damage testing of KDP using LLNL's Zeus automated damage test system has allowed the statistics of KDP bulk damage to be investigated. Samples are now characterized by the cumulative damage probability curve, or S-curve, that is generated from hundreds of individual test sites per sample. A HeNe laser/PMT scatter diagnostic is used to determine the onset of damage at each test site. The nature of KDP bulk damage is such that each scatter signal may possess many different indicators of a damage event. Because of this, the determination of the initial onset for each scatter trace is not a straightforward affair and has required considerable manual analysis. The amount of testing required by crystal development for the National Ignition Facility (NIF) has made it impractical to continue analysis by hand. Because of this, we have developed and implemented algorithms for analyzing the scatter traces by computer. We discuss the signal cleaning algorithms and damage determination criteria that have lead to the successful implementation of a LabView based analysis code. For the typical R/1 damage data set, the program can find the correct damage onset in more than 80% of the cases, with the remaining 20% being left to operator determination. The potential time savings for data analysis is on the order of ∼ 100X over manual analysis and is expected to result in the savings of at least 400 man-hours over the next 3 years of NIF quality assurance testing

  18. Damage to Aspergillus fumigatus and Rhizopus oryzae Hyphae by Oxidative and Nonoxidative Microbicidal Products of Human Neutrophils In Vitro

    OpenAIRE

    Diamond, Richard D.; Clark, Robert A.

    1982-01-01

    Our previous studies established that human neutrophils could damage and probably kill hyphae of Aspergillus fumigatus and Rhizopus oryzae in vitro, primarily by oxygen-dependent mechanisms active at the cell surface. These studies were extended, again quantitating hyphal damage by reduction in uptake of 14C-labeled uracil or glutamine. Neither A. fumigatus nor R. oryzae hyphae were damaged by neutrophils from patients with chronic granulomatous disease, confirming the importance of oxidative...

  19. A Coupled Plastic Damage Model for Concrete considering the Effect of Damage on Plastic Flow

    OpenAIRE

    Zhou, Feng; Cheng, Guangxu

    2015-01-01

    A coupled plastic damage model with two damage scalars is proposed to describe the nonlinear features of concrete. The constitutive formulations are developed by assuming that damage can be represented effectively in the material compliance tensor. Damage evolution law and plastic damage coupling are described using the framework of irreversible thermodynamics. The plasticity part is developed without using the effective stress concept. A plastic yield function based on the true stress is ado...

  20. Legal protection against nuclear damage

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1959-04-15

    The IAEA Director General appointed an international Panel of Experts to go into the question of Civil Liability and State Responsibility for Nuclear Hazards. The Panel had before it certain basic postulates formulated after a preliminary and tentative consideration of the subject. From the viewpoint of the public, the first postulate is, of course, that the use of nuclear energy be regulated by adequate licensing and control mechanisms so as to prevent any accidents. To the extent, however, that nuclear damage cannot be prevented, there must be liability on the part of the enterprise which caused the damage and, where damage exceeds its liability or its financial resources there should be some assurance of compensation by the State. This should be so not only within the borders of one State, but especially also on an international basis. Security should be required for the possible liability of the enterprises connected with a nuclear incident. Litigation with respect to liability should be concentrated in the most convenient tribunal and be governed by a single clearly defined law. The methods of distribution should meet general standards of equity and be as expeditious as possible. Emergency measures, especially evacuation, first aid and decontamination, should be organized and financed without delay. At the same time, the liability of an enterprise should not exceed its reasonable financial capabilities. This means that a ceiling should be imposed upon the amount of third party liability to which an enterprise could be held. And the liability should generally be such as can be covered by adequate financial security. Uniformity in the treatment of victims of nuclear incidents in all these fields is a desirable goal. Yet, if a rule adopted on an international level or suggested by uniform legislation were to be viable, it should adapt itself to the social, economic and legal order already existing in individual States. This may mean that in certain fields it

  1. Legal protection against nuclear damage

    International Nuclear Information System (INIS)

    1959-01-01

    The IAEA Director General appointed an international Panel of Experts to go into the question of Civil Liability and State Responsibility for Nuclear Hazards. The Panel had before it certain basic postulates formulated after a preliminary and tentative consideration of the subject. From the viewpoint of the public, the first postulate is, of course, that the use of nuclear energy be regulated by adequate licensing and control mechanisms so as to prevent any accidents. To the extent, however, that nuclear damage cannot be prevented, there must be liability on the part of the enterprise which caused the damage and, where damage exceeds its liability or its financial resources there should be some assurance of compensation by the State. This should be so not only within the borders of one State, but especially also on an international basis. Security should be required for the possible liability of the enterprises connected with a nuclear incident. Litigation with respect to liability should be concentrated in the most convenient tribunal and be governed by a single clearly defined law. The methods of distribution should meet general standards of equity and be as expeditious as possible. Emergency measures, especially evacuation, first aid and decontamination, should be organized and financed without delay. At the same time, the liability of an enterprise should not exceed its reasonable financial capabilities. This means that a ceiling should be imposed upon the amount of third party liability to which an enterprise could be held. And the liability should generally be such as can be covered by adequate financial security. Uniformity in the treatment of victims of nuclear incidents in all these fields is a desirable goal. Yet, if a rule adopted on an international level or suggested by uniform legislation were to be viable, it should adapt itself to the social, economic and legal order already existing in individual States. This may mean that in certain fields it

  2. Preliminary observations of environmental damage due to the Gulf War

    International Nuclear Information System (INIS)

    El-Baz, F.

    1992-01-01

    Preparing for and conducting the Gulf War resulted in much damage to the environment of the region. The first and most visible effect is related to the damage caused by oil well fires in terms of air pollution as well as the potential damage to the petroleum reservoirs. The second detrimental effect has been caused by the oil spill in the Gulf water. Hundreds of miles of the western coastline of the Gulf are already covered with oil. Petroleum 'mats' have settled on coral reefs and have reduced Gulf water productivity. Foremost among the irreparable damages are changes to the terrain due to the digging of trenches, building walls of soil and otherwise disturbing the desert pavement in and around Kuwait. Disruption of the, usually, one-grain thick layer of pebbles on the desert floor exposes soil to wind action. Changing the contours of the normally flat land increases resistance to the wind and increases the potential of particle transport until the land is peneplained. This condition will increase the frequency and the ferocity of dust storms in the region. It will also result in the formation of new sand dunes; sand drifts already exist along roads in northern Kuwait. It is believed that the detrimental effects on the atmosphere will last for years, on the Gulf water for decades, and on the desert surface for centuries. (author). 12 refs, 1 fig

  3. Damage Detection for Historical Architectures Based on Tls Intensity Data

    Science.gov (United States)

    Li, Q.; Cheng, X.

    2018-04-01

    TLS (Terrestrial Laser Scanner) has long been preferred in the cultural heritage field for 3D documentation of historical sites thanks to its ability to acquire the geometric information without any physical contact. Besides the geometric information, most TLS systems also record the intensity information, which is considered as an important measurement of the spectral property of the scanned surface. Recent studies have shown the potential of using intensity for damage detection. However, the original intensity is affected by scanning geometry such as range and incidence angle and other factors, thus making the results less accurate. Therefore, in this paper, we present a method to detect certain damage areas using the corrected intensity data. Firstly, two data-driven models have been developed to correct the range and incidence angle effect. Then the corrected intensity is used to generate 2D intensity images for classification. After the damage areas being detected, they are re-projected to the 3D point cloud for better visual representation and further investigation. The experiment results indicate the feasibility and validity of the corrected intensity for damage detection.

  4. Visual method for detecting critical damage in railway contact strips

    Science.gov (United States)

    Judek, S.; Skibicki, J.

    2018-05-01

    Ensuring an uninterrupted supply of power in the electric traction is vital for the safety of this important transport system. For this purpose, monitoring and diagnostics of the technical condition of the vehicle’s power supply elements are becoming increasingly common. This paper presents a new visual method for detecting contact strip damage, based on measurement and analysis of the movement of the overhead contact line (OCL) wire. A measurement system configuration with a 2D camera was proposed. The experimental method has shown that contact strips damage can be detected by transverse displacement signal analysis. It has been proven that the velocity signal numerically established on that basis has a comparable level in the case of identical damage, regardless of its location on the surface of the contact strip. The proposed method belongs to the group of contact-less measurements, so it does not require interference with the structure of the catenary network nor the mounting of sensors in its vicinity. Measurement of displacements of the contact wire in 2D space makes it possible to combine the functions of existing diagnostic stands assessing the correctness of the mean contact force control adjustment of the current collector with the elements of the contact strip diagnostics, which involves detecting their damage which may result in overhead contact line rupture.

  5. Damage detection with concentrated configurations of piezoelectric transducers

    International Nuclear Information System (INIS)

    Wandowski, T; Malinowski, P; Ostachowicz, W M

    2011-01-01

    In this paper results of investigation on concentrated piezoelectric networks with different configurations are presented. They were used for elastic wave generation and acquisition. The elastic wave propagation phenomenon was used for damage localization in thin aluminium panels. This approach utilized the fact that any discontinuities existing in structural elements cause local changes of physical material properties which affect elastic wave propagation. Elastic waves were excited and received using piezoelectric transducer networks with different element arrangements. The method of transducer placement and the number of piezoelectric elements used had an influence on the accuracy of the damage localization algorithm. Obviously, the more elements there were, the more data had to be processed. After the acquisition process signal processing was conducted in order to create damage influence maps. These maps presents elastic wave energy connected with reflection from discontinuities. In order to create such a map a computer program was developed that assigns a mesh of points to the panel surface. At each point the energy of elastic wave reflection was calculated. This energy was extracted from the acquired signals. This paper summarizes an extensive experimental investigation that included three damage scenarios and twelve transducer configurations

  6. Preliminary observations of environmental damage due to the Gulf War

    Energy Technology Data Exchange (ETDEWEB)

    El-Baz, F [Boston Univ., Boston, MA (United States). Center for Remote Sensing

    1992-02-01

    Preparing for and conducting the Gulf War resulted in much damage to the environment of the region. The first and most visible effect is related to the damage caused by oil well fires in terms of air pollution as well as the potential damage to the petroleum reservoirs. The second detrimental effect has been caused by the oil spill in the Gulf water. Hundreds of miles of the western coastline of the Gulf are already covered with oil. Petroleum 'mats' have settled on coral reefs and have reduced Gulf water productivity. Foremost among the irreparable damages are changes to the terrain due to the digging of trenches, building walls of soil and otherwise disturbing the desert pavement in and around Kuwait. Disruption of the, usually, one-grain thick layer of pebbles on the desert floor exposes soil to wind action. Changing the contours of the normally flat land increases resistance to the wind and increases the potential of particle transport until the land is peneplained. This condition will increase the frequency and the ferocity of dust storms in the region. It will also result in the formation of new sand dunes; sand drifts already exist along roads in northern Kuwait. It is believed that the detrimental effects on the atmosphere will last for years, on the Gulf water for decades, and on the desert surface for centuries. (author). 12 refs, 1 fig.

  7. Fuel containment, lightning protection and damage tolerance in large composite primary aircraft structures

    Science.gov (United States)

    Griffin, Charles F.; James, Arthur M.

    1985-01-01

    The damage-tolerance characteristics of high strain-to-failure graphite fibers and toughened resins were evaluated. Test results show that conventional fuel tank sealing techniques are applicable to composite structures. Techniques were developed to prevent fuel leaks due to low-energy impact damage. For wing panels subjected to swept stroke lightning strikes, a surface protection of graphite/aluminum wire fabric and a fastener treatment proved effective in eliminating internal sparking and reducing structural damage. The technology features developed were incorporated and demonstrated in a test panel designed to meet the strength, stiffness, and damage tolerance requirements of a large commercial transport aircraft. The panel test results exceeded design requirements for all test conditions. Wing surfaces constructed with composites offer large weight savings if design allowable strains for compression can be increased from current levels.

  8. A modified bonded-interface technique with improved features for studying indentation damage of materials

    International Nuclear Information System (INIS)

    Low, I.M.

    1998-01-01

    A modified 'bonded-interface' technique with improved features for studying contact damage of ceramic (Al 2 O 3 graded Al 2 TiO 5 /Al 2 O 3 , Ti 3 SiC 2 ) and non-ceramic (epoxy, tooth) materials is developed and compared with the conventional method. This technique enables the surface damage around and below an indentor to be studied. When used in conjunction with Nomarski illumination and atomic force microscopy, this technique can reveal substantial information on the topography of indentation surface damage. In particular, it is ideal for monitoring the evolution of deformation-micro fracture damage of quasi-plastic materials. The technique is much less sophisticated, less time consuming, and user-friendly. It does not require a highly experience user to be proficient in the procedure. When compared with the conventional tool- clamp method, this modified technique gives similar, if not, identical results. Copyright (1998) Australasian Ceramic Society

  9. Reduction of damage initiation density in fused silica optics via UV laser conditioning

    Science.gov (United States)

    Peterson, John E.; Maricle, Stephen M.; Brusasco, Raymond M.; Penetrante, Bernardino M.

    2004-03-16

    The present invention provides a method for reducing the density of sites on the surface of fused silica optics that are prone to the initiation of laser-induced damage, resulting in optics which have far fewer catastrophic defects and are better capable of resisting optical deterioration upon exposure for a long period of time to a high-power laser beam having a wavelength of about 360 nm or less. The initiation of laser-induced damage is reduced by conditioning the optic at low fluences below levels that normally lead to catastrophic growth of damage. When the optic is then irradiated at its high fluence design limit, the concentration of catastrophic damage sites that form on the surface of the optic is greatly reduced.

  10. Wireless Damage Location Sensing System

    Science.gov (United States)

    Woodard, Stanley E. (Inventor); Taylor, Bryant Douglas (Inventor)

    2012-01-01

    A wireless damage location sensing system uses a geometric-patterned wireless sensor that resonates in the presence of a time-varying magnetic field to generate a harmonic response that will experience a change when the sensor experiences a change in its geometric pattern. The sensing system also includes a magnetic field response recorder for wirelessly transmitting the time-varying magnetic field and for wirelessly detecting the harmonic response. The sensing system compares the actual harmonic response to a plurality of predetermined harmonic responses. Each predetermined harmonic response is associated with a severing of the sensor at a corresponding known location thereof so that a match between the actual harmonic response and one of the predetermined harmonic responses defines the known location of the severing that is associated therewith.

  11. [Damage control in field surgery].

    Science.gov (United States)

    Samokhvalov, I M; Manukovskiĭ, V A; Badalov, V I; Severin, V V; Golovko, K P; Denisenko, V V

    2011-09-01

    Damage control surgery (DCS) is an important option in the store of war surgery and surgery of trauma. The main purpose of our investigation was to specify the percentage of the injured who need DCS. We performed retrospective study of the patients in the combat operations in Chechnya (1994-2002) and in peacetime (2005-2010). Total lethality in group with the standard surgical approach was 62.3%. It was significantly higher than the lethality in group of patients who underwent DCS - 50.0% (p < 0.05). Thus, the experience of DCS in War Surgery Department confirms that DCS is perspective tendency in treatment of patients with severe and extremely severe trauma, and allows decreasing lethality in 12.3%.

  12. Radiation damages in superconducting materials

    International Nuclear Information System (INIS)

    Heinz, W.; Seibt, E.

    1978-01-01

    Radiation damage investigations of technical superconductors are reported and discussed with respect to their main properties like critical current jsub(c), transition temperature Tsub(c), upper critical field Bsub(c2), pinning and annealing behaviour. Ordered A15 type alloys (like Nb 3 Sn and V 3 Ga) show significant reductions of all critical parameters above a threshold of about 2x10 21 m -2 with 50 MeV deuterons corresponding to 2x10 22 neutrons/m 2 (Esub(n)>0.1 MeV). Pure metals and disordered B1 type alloys (like Nb or NbTi) show only a small linear decrease in critical parameters (except Bsub(c2) of niobium). Experimental results are compared with theoretical calculations. (author)

  13. Mesoscopic scale thermal fatigue damage

    International Nuclear Information System (INIS)

    Robertson, C.; Fissolo, A.; Fivel, M.

    2001-01-01

    In an attempt to better understand damage accumulation mechanisms in thermal fatigue, dislocation substructures forming in 316L steel during one specific test were examined and simulated. Hence, thin foils taken out of massive, tested specimens were first observed in transmission electron microscopy (TEM). These observations help in determining one initial dislocation configuration to be implemented in a 3-D model combining 3D discrete dislocation dynamics simulation (DDD) and finite element method computations (FEM). It was found that the simulated mechanical behaviour of the DDD microstructure is compatible with FEM and experimental data. The numerically generated dislocation microstructure is similar to ladder-like dislocation arrangements as found in many fatigued f.c.c. materials. Distinct mechanical behaviour for the two active slip systems was shown and deformation mechanisms were proposed. (authors)

  14. Mesoscopic scale thermal fatigue damage

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, C.; Fissolo, A. [CEA Saclay, Dept. des Materiaux pour le Nucleaire, DMN, 91 - Gif sur Yvette (France); Fivel, M. [Centre National de la Recherche Scientifique, CNRS-GPM2, 38 - Saint Martin d' Heres (France)

    2001-07-01

    In an attempt to better understand damage accumulation mechanisms in thermal fatigue, dislocation substructures forming in 316L steel during one specific test were examined and simulated. Hence, thin foils taken out of massive, tested specimens were first observed in transmission electron microscopy (TEM). These observations help in determining one initial dislocation configuration to be implemented in a 3-D model combining 3D discrete dislocation dynamics simulation (DDD) and finite element method computations (FEM). It was found that the simulated mechanical behaviour of the DDD microstructure is compatible with FEM and experimental data. The numerically generated dislocation microstructure is similar to ladder-like dislocation arrangements as found in many fatigued f.c.c. materials. Distinct mechanical behaviour for the two active slip systems was shown and deformation mechanisms were proposed. (authors)

  15. Assessing smoke damage. First report

    Energy Technology Data Exchange (ETDEWEB)

    Andre, F; Hartig, W

    1957-06-01

    Briefly described are experiments comparing air pollution tests with rags impregnated with BaO, hung both in the tree tops and below the canopy of Spruce stands, with analyses of needles collected at the same points. S content of the atmosphere (expressed in mg H/sub 2/SO/sub 4/ content of the rags) was, at equal distances, markedly greater above than below the closed canopy, suggesting that the tallest trees would suffer most. While absolute S content of needles (also expressed in mg H/sub 2/SO/sub 4/) gave no indication of smoke damage, relative differences in S content between 1-year-old and 5-year-old needles proved to be a useful indication.

  16. Apophyseal damage in adolescent athlete

    International Nuclear Information System (INIS)

    Nehrer, S.; Huber, W.; Dirisamer, A.; Kainberger, F.

    2002-01-01

    The increasing demands on the adolescent athlete in high perfomance sports puts high biomechanical stress on the growing structures of the active and passive locomotor system. The ''growing factor'' itself increases stretching forces on tendon insertions, which are often overloaded when a physical demanding sport is performed additionally. The apophysis is an ossification nucleus near the tendon insertion, which appears before the growing age resumes and these apophysis finally fuses with the adjacent bone. The tensile forces from vigorous sports activity leads to a chronic or acute avulsion of the ossifying tendon insertion. The radiological appearance of this apophyseal damage with ossification and osteolytic processes is sometimes difficult with respect to differential diagnoses. Apophyseal impairment is associated with pain, tenderness to palpation and decreased muscle function. If it is not diagnosed and treated properly it can lead to end of career in many adolescent athletes. (orig.) [de

  17. Nanofoams Response to Radiation Damage

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Engang [Los Alamos National Laboratory; Serrano De Caro, Magdalena [Los Alamos National Laboratory; Wang, Yongqiang [Los Alamos National Laboratory; Nastasi, Michael [Nebraska Center for Energy Sciences Research, University of Nebraska-Lincoln, NE 68508; Zepeda-Ruiz, Luis [PLS, Lawrence Livermore National Laboratory, Livermore, CA 94551; Bringa, Eduardo M. [CONICET and Inst. Ciencias Basicas, Universidad Nacional de Cuyo, Mendoza, 5500 Argentina; Baldwin, Jon K. [Los Alamos National Laboratory; Caro, Jose A. [Los Alamos National Laboratory

    2012-07-30

    Conclusions of this presentation are: (1) np-Au foams were successfully synthesized by de-alloying process; (2) np-Au foams remain porous structure after Ne ion irradiation to 1 dpa; (3) SFTs were observed in irradiated np-Au foams with highest and intermediate flux, while no SFTs were observed with lowest flux; (4) SFTs were observed in irradiated np-Au foams at RT, whereas no SFTs were observed at LNT irradiation; (5) The diffusivity of vacancies in Au at RT is high enough so that the vacancies have enough time to agglomerate and thus collapse. As a result, SFTs were formed; (6) The high flux created much more damage/time, vacancies don't have enough time to diffuse or recombine. As a result, SFTs were formed.

  18. First results from electron-photon damage equivalence studies on a generic ethylene-propylene rubber

    International Nuclear Information System (INIS)

    Buckalew, W.H.

    1986-04-01

    As part of a simulator adequacy assessment program, the relative effectiveness of electrons and photons to produce damage in a generic ethylene propylene rubber (EPR) has been investigated. The investigation was limited in extent in that a single EPR material, in three thickness, was exposed to Cobalt-60 photons and three electron beam energies. Basing material damage on changes in the EPR mechanical properties elongation and tensile strength, we observed that EPR damage was a smoothly varying function of absorbed energy and independent of irradiating particle type. EPR damage tracked equally well as a function of both incident particle energy and material front surface dose. Based on these preliminary data, we tentatively concluded that a correlation between particle, particle energy, and material damage (as measured by changes in material elongation and/or tensile strength) has been demonstrated. 14 figs

  19. A frictional contact problem with wear involving elastic-viscoplastic materials with damage and thermal effects

    Directory of Open Access Journals (Sweden)

    Abdelmoumene Djabi

    2015-05-01

    Full Text Available We consider a mathematical problem for quasistatic contact between a thermo-elastic-viscoplastic body with damage and an obstacle. The contact is frictional and bilateral with a moving rigid foundation which results in the wear of the contacting surface. We employ the thermo-elasticviscoplastic with damage constitutive law for the material. The damage of the material caused by elastic deformations. The evolution of the damage is described by an inclusion of parabolic type. The problem is formulated as a coupled system of an elliptic variational inequality for the displacement, a parabolic variational inequality for the damage and the heat equation for the temperature. We establish a variational formulation for the model and we prove the existence of a unique weak solution to the problem. The proof is based on a classical existence and uniqueness result on parabolic inequalities, differential equations and fixed point arguments.

  20. Terrorism and nuclear damage coverage

    International Nuclear Information System (INIS)

    Horbach, N. L. J. T.; Brown, O. F.; Vanden Borre, T.

    2004-01-01

    This paper deals with nuclear terrorism and the manner in which nuclear operators can insure themselves against it, based on the international nuclear liability conventions. It concludes that terrorism is currently not covered under the treaty exoneration provisions on 'war-like events' based on an analysis of the concept on 'terrorism' and travaux preparatoires. Consequently, operators remain liable for nuclear damage resulting from terrorist acts, for which mandatory insurance is applicable. Since nuclear insurance industry looks at excluding such insurance coverage from their policies in the near future, this article aims to suggest alternative means for insurance, in order to ensure adequate compensation for innocent victims. The September 11, 2001 attacks at the World Trade Center in New York City and the Pentagon in Washington, DC resulted in the largest loss in the history of insurance, inevitably leading to concerns about nuclear damage coverage, should future such assaults target a nuclear power plant or other nuclear installation. Since the attacks, some insurers have signalled their intentions to exclude coverage for terrorism from their nuclear liability and property insurance policies. Other insurers are maintaining coverage for terrorism, but are establishing aggregate limits or sublimits and are increasing premiums. Additional changes by insurers are likely to occur. Highlighted by the September 11th events, and most recently by those in Madrid on 11 March 2004, are questions about how to define acts of terrorism and the extent to which such are covered under the international nuclear liability conventions and various domestic nuclear liability laws. Of particular concern to insurers is the possibility of coordinated simultaneous attacks on multiple nuclear facilities. This paper provides a survey of the issues, and recommendations for future clarifications and coverage options.(author)