Sample records for stress measurement results

  1. Critical study of the method of calculating virgin rock stresses from measurement results of the CSIR triaxial strain cell

    Vreede, F. A.


    The manual of instructions for the user of the CSIR triaxial rock stress measuring equipment is critically examined. It is shown that the values of the rock stresses can be obtained from the strain gauge records by means of explicit formulae, which makes the manual's computer program obsolete. Furthermore statistical methods are proposed to check for faulty data and inhomogeneity in rock properties and virgin stress. The possibility of non-elastic behavior of the rock during the test is also checked. A new computer program based on the explicit functions and including the check calculations is presented. It is much more efficient than the one in the manual since it does not require computer sub-routines, allowing it to be used directly on any modern computer. The output of the new program is in a format suitable for direct inclusion in the report of an investigation using strain cell results.

  2. Normal and shear stresses on a residual limb in a prosthetic socket during ambulation: comparison of finite element results with experimental measurements.

    Sanders, J E; Daly, C H


    Interface stresses on a below-knee amputee residual limb during the stance phase of gait calculated using an analytical finite element model were compared with experimental interface stress measurements. The model was quasi-static and linear. Qualitatively, shapes of analytical and experimental interface stress waveforms were similar in that they were double-peaked with some distinct features apparent. However, quantitatively analytical resultant shear stress magnitudes were less than experimental values at all transducer measurement sites. Analytical normal stresses were less than experimental values at postero-proximal, postero-distal, and anteromedial proximal sites, but were greater than experimental values at antero-lateral distal and antero-lateral proximal sites. Anterior resultant shear angles were directed more distally in the model than in clinical data, an expected result since there was no relief for the tibial crest in the model. Model sensitivity analyses to shank loads showed interface normal and resultant shear stresses were most sensitive to axial force, sagittal bending moment, or sagittal shear force. The finite element model presented in this paper is significant because it contributes toward development of an analytical modeling technique to predict interface stress distributions for proposed prosthetic designs, provides insight into physical explanations of features apparent in interface stress waveforms (thereby enhancing understanding of interface mechanics), and provides insight into nonlinear characteristics that need to be added to improve the model.

  3. Residual-stress measurements

    Ezeilo, A.N.; Webster, G.A. [Imperial College, London (United Kingdom); Webster, P.J. [Salford Univ. (United Kingdom)


    Because neutrons can penetrate distances of up to 50 mm in most engineering materials, this makes them unique for establishing residual-stress distributions non-destructively. D1A is particularly suited for through-surface measurements as it does not suffer from instrumental surface aberrations commonly found on multidetector instruments, while D20 is best for fast internal-strain scanning. Two examples for residual-stress measurements in a shot-peened material, and in a weld are presented to demonstrate the attractive features of both instruments. (author).

  4. Preliminary Results of In-situ Stress Measurements along the Longmenshan Fault Zone after the Wenchuan Ms 8.0 Earthquake

    WU Manlu; ZHANG Yueqiao; LIAO Chunting; CHEN Qunce; MA Yinsheng; WU Jinsheng; YAN Junfeng; OU Mingyi


    Four months after the Wenchuan Ms 8 earthquake in western Sichuan, China, in situ stress measurements were carried out along the Longmenshan fault zone with the purpose of obtaining stress parameters for earthquake hazard assessment. In-situ stresses were measured in three new boreholes by using overcoring with the piezomagnetic stress gauges for shallow depths and hydraulic fracturing for lower depths. The maximum horizontal stress in shallow depths (~20 m) is about 4.3 MPa, oriented NI9°E, in the epicenter area at Yingxiu Town, about 9.7 MPa, oriented N51°W, at Baoxing County in the southwestern Longmenshan range, and about 2.6 MPa, oriented N39°E, near Kangding in the southernmost zone of the Longmenshan range. Hydraulic fracturing at borehole depths from 100 to 400 m shows a tendency towards increasing stress with depth. A comparison with the results measured before the Wenchuan earthquake along the Longmenshan zone and in the Tibetan Plateau demonstrates that the stress level remains relatively high in the southwestern segment of the Longmenshan range, and is still moderate in the epicenter zone. These results provide a key appraisal for future assessment of earthquake hazards of the Longmenshan fault zone and the aftershock occurrences of the Wenchuan earthquake.

  5. Outcome measure for stress urinary incontinence treatment (OMIT): results of two society of urodynamics and female urology (SUFU) surveys.

    Zimmern, Philippe; Kobashi, Kathleen; Lemack, Gary


    To reach some agreement on a minimum set of outcomes measures (OMs) for the post-operative evaluation of stress incontinent women, we applied the concept of "lower common denominator" to study which OM instruments are used amongst SUFU members. With SUFU approval, a short online, 11 items, email-based survey was prepared to assess what OMs current SUFU members are using in daily practice. The first survey administered after the annual SUFU meeting targeted recent SUFU meeting attendees. The same survey was redistributed later on to include all SUFU members. Each survey ran for a 10-day period. Response rate for the first survey was 50 (approximately 30%) and 106 (approximately 25%) for the second. Responders were geographically well distributed, had been in practice for 1-15 years (approximately 75%), performed 5-15 cases/month, and practiced in a university (56%) or group (30%) setting. Great consistency was noted between surveys for preferred questionnaires [UDI-6 (40-52%), UDI-6, and IIQ-7 (30-34%)], office tests [urinalysis and post-void residual (30-35%)], exam [Baden-Walker and/or POP-Q (38-55%), cough stress test (54-51%)], imaging (none), and urodynamics (none, unless complications). The most common "dislikes" in descending order were: 24 hr pad test, Q-tip test, bladder diary, long questionnaires, POP-Q. These two SUFU surveys did not explore what each physician thinks is the best OM but what members use regularly in their practices. Similar findings were noted in both surveys, supporting the concept that a minimum set of OM could be developed for reporting surgical outcomes of incontinence procedures in the future. (c) 2010 Wiley-Liss, Inc.

  6. Preliminary Results of Stress Measurement Using Drill Cores of TCDP Hole-A: an Application of Anelastic Strain Recovery Method to Three-Dimensional In-Situ Stress Determination

    Weiren Lin En-Chao Yeh1


    Full Text Available In order to understand the feature of rock stress change at different depths above, within, and beneath the Chelungpu fault after the Chi-Chi earthquake, we employed a core-based stress measurement method, anelastic strain recovery (ASR technique to determine both the orientations and magnitudes of present three-dimensional principal rock stresses using drill core samples retrieved from Taiwan Chelungpu-fault Drilling Project (TCDP main Hole-A. The core samples used were taken from three depths; and their lithology were sandstone at depths of 592 and 1755 m and siltstone at 1112 m. The anelastic strains of the specimens in nine directions, including six independent directions, were measured after its in-situ stress was released. Acquired anelastic strains were of high quality and reached several hundred microstrains, which is sufficiently high for the accuracy of the measurement system used. Thus, the strain data could be used for three dimensional analysis resulting in the determination of orientations and the estimation of magnitudes of the principal in-situ stresses. Preliminary stress measurement results showed that the orientations of principal stresses changed between the shallower depth above the fault and the deeper depth beneath it, that is, the present stress distribution in the TCDP hole might be influenced by the Chelungpu fault rupture. At the same time, anelastic strain recovery measurement is well suited for the task of directly determining the orientations of principal in-situ stresses and to estimate the magnitude of stresses at large/great depth.


    Rudolph, J


    The linear accelerator ELBE delivers high-brightness electron bunches to multiple user stations, including two IR-FEL oscillators [1], [2]. In the framework of an upgrade program the current thermionic injector is being replaced by a SRF-photoinjector [3], [4]. The SRF injector promises higher beam quality, especially required for future experiments with high power laser radiation. During the commissioning phase, the SRF-injector was running in parallel to the thermionic gun. After installation of a injection beamline (dogleg), beam from the SRF-injector can now be injected into the ELBE linac. Detailed characterization of the electron beam quality delivered by the new electron injector includes vertical slice emittance measurements in addition to measurements of projected emittance values. This report gives an overview of the status of the project and summarizes first measurement results as well as results of simulations performed with measurement settings.

  8. Interferometric Measurement Of Residual Stress

    Danyluk, Steven; Andonian, A. T.


    Stress averaged through thickness of plate measured nondestructively. Theory of elasticity combined with laser interferometric technique into technique for measurement of residual stresses in solid objects - usually in thin, nominally-flat plates. Measurements particularly useful in inspection of wafers of single-crystal silicon for making solar cells or integrated circuits, because stresses remaining after crystal-growing process cause buckling or fracture. Used to predict deflections of plates caused by known applied loads under specified boundary condition, or to infer applied loads that cause known deflections. Also used to relate known deflections to residual stresses equivalent to stresses produced by fictitious applied loads.

  9. Electromechanical Apparatus Measures Residual Stress

    Chern, Engmin J.; Flom, Yury


    Nondestructive test exploits relationship between stress and eddy-current-probe resistance. Yields data on residual stress or strain in metal tension/compression specimen (stress or strain remaining in specimen when no stress applied from without). Apparatus is assembly of commercial equipment: tension-or-compression testing machine, eddy-current probe, impedance gain-and-phase analyzer measuring impedance of probe coil, and desktop computer, which controls other equipment and processes data received from impedance gain-and-phase analyzer.

  10. Residual stress measurements in carbon steel

    Heyman, J. S.; Min, N.


    External dc magnetic field-induced changes in natural velocity of Rayleigh surface waves were measured in steel specimens under various stress conditions. The low field slopes of curves representing the fractional changes of natural velocity were proved to provide correct stress information in steels with different metallurgical properties. The slopes of curves under uniaxial compression, exceeding about one third of the yield stress, fell below zero in all the specimens when magnetized along the stress axis. The slopes under tension varied among different steels but remained positive in any circumstances. The stress effect was observed for both applied and residual stress. A physical interpretation of these results is given based on the stress-induced domain structure changes and the delta epsilon effect. Most importantly, it is found that the influence of detailed metallurgical properties cause only secondary effects on the obtained stress information.

  11. Experimental Measurement of In Situ Stress

    Tibbo, Maria; Milkereit, Bernd; Nasseri, Farzine; Schmitt, Douglas; Young, Paul


    The World Stress Map data is determined by stress indicators including earthquake focal mechanisms, in situ measurement in mining, oil and gas boreholes as well as the borehole cores, and geologic data. Unfortunately, these measurements are not only infrequent but sometimes infeasible, and do not provide nearly enough data points with high accuracy to correctly infer stress fields in deep mines around the world. Improvements in stress measurements of Earth's crust is fundamental to several industries such as oil and gas, mining, nuclear waste management, and enhanced geothermal systems. Quantifying the state of stress and the geophysical properties of different rock types is a major complication in geophysical monitoring of deep mines. Most stress measurement techniques involve either the boreholes or their cores, however these measurements usually only give stress along one axis, not the complete stress tensor. The goal of this project is to investigate a new method of acquiring a complete stress tensor of the in situ stress in the Earth's crust. This project is part of a comprehensive, exploration geophysical study in a deep, highly stressed mine located in Sudbury, Ontario, Canada, and focuses on two boreholes located in this mine. These boreholes are approximately 400 m long with NQ diameters and are located at depths of about 1300 - 1600 m and 1700 - 2000 m. Two borehole logging surveys were performed on both boreholes, October 2013 and July 2015, in order to perform a time-lapse analysis of the geophysical changes in the mine. These multi-parameter surveys include caliper, full waveform sonic, televiewer, chargeability (IP), and resistivity. Laboratory experiments have been performed on borehole core samples of varying geologies from each borehole. These experiments have measured the geophysical properties including elastic modulus, bulk modulus, P- and S-wave velocities, and density. The apparatus' used for this project are geophysical imaging cells capable

  12. Measurements for stresses in machine components

    Yakovlev, V F


    Measurements for Stresses in Machine Components focuses on the state of stress and strain of components and members, which determines the service life and strength of machines and structures. This book is divided into four chapters. Chapter I describes the physical basis of several methods of measuring strains, which includes strain gauges, photoelasticity, X-ray diffraction, brittle coatings, and dividing grids. The basic concepts of the electric strain gauge method for measuring stresses inside machine components are covered in Chapter II. Chapter III elaborates on the results of experim

  13. Bottom stress measurements on the inner shelf

    Sherwood, Christopher R.; Scully, Malcolm; Trowbridge, John


    Bottom stress shapes the mean circulation patterns, controls sediment transport, and influences benthic habitat in the coastal ocean. Accurate and precise measurements of bottom stress have proved elusive, in part because of the difficulty in separating the turbulent eddies that transport momentum from inviscid wave-induced motions. Direct covariance measurements from a pair of acoustic Doppler velocimeters has proved capable of providing robust estimates, so we designed a mobile platform coined the NIMBBLE for these measurements, and deployed two of them and two more conventional quadpods at seven sites on the inner shelf over a period of seven months. The resulting covariance estimates of stress and bottom roughness were lower than log-fit estimates, especially during calmer periods. Analyses of these data suggest the NIMBBLEs may provide an accurate and practical method for measuring bottom stress.

  14. Neutron stress measurement of W-fiber reinforced Cu composite

    Nishida, M; Ikeuchi, Y; Minakawa, N


    Stress measurement methods using neutron and X-ray diffraction were examined by comparing the surface stresses with internal stresses in the continuous tungsten-fiber reinforced copper-matrix composite. Surface stresses were measured by X-ray stress measurement with the sin sup 2 psi method. Furthermore, the sin sup 2 psi method and the most common triaxal measurement method using Hooke's equation were employed for internal stress measurement by neutron diffraction. On the other hand, microstress distributions developed by the difference in the thermal expansion coefficients between these two phases were calculated by FEM. The weighted average strains and stresses were compared with the experimental results. The FEM results agreed with the experimental results qualitatively and confirmed the importance of the triaxial stress analysis in the neutron stress measurement. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  15. Residual Stress Determination from a Laser-Based Curvature Measurement

    Swank, William David; Gavalya, Rick Allen; Wright, Julie Knibloe; Wright, Richard Neil


    Thermally sprayed coating characteristics and mechanical properties are in part a result of the residual stress developed during the fabrication process. The total stress state in a coating/substrate is comprised of the quench stress and the coefficient of thermal expansion (CTE) mismatch stress. The quench stress is developed when molten particles impact the substrate and rapidly cool and solidify. The CTE mismatch stress results from a large difference in the thermal expansion coefficients of the coating and substrate material. It comes into effect when the substrate/coating combination cools from the equilibrated deposit temperature to room temperature. This paper describes a laser-based technique for measuring the curvature of a coated substrate and the analysis required to determine residual stress from curvature measurements. Quench stresses were determined by heating the specimen back to the deposit temperature thus removing the CTE mismatch stress. By subtracting the quench stress from the total residual stress at room temperature, the CTE mismatch stress was estimated. Residual stress measurements for thick (>1mm) spinel coatings with a Ni-Al bond coat on 304 stainless steel substrates were made. It was determined that a significant portion of the residual stress results from the quenching stress of the bond coat and that the spinel coating produces a larger CTE mismatch stress than quench stress.

  16. Neutron residual stress measurements in linepipe

    Law, Michael [ANTSO, PMB1 Menai, NSW, 2234 (Australia)]. E-mail:; Gnaepel-Herold, Thomas [Department of Materials Science and Engineering, NCNR and University of Maryland (United States); Luzin, Vladimir [Department of Materials Science and Engineering, NCNR and University of Maryland (United States); Bowie, Graham [cNCNR and State University of New York at Stoneybrook (United States): Blue Scope Steel (Australia)


    Residual stresses in gas pipelines are generated by manufacturing and construction processes and may affect the subsequent pipe integrity. In the present work, the residual stresses in eight samples of linepipe were measured by neutron diffraction. Residual stresses changed with some coating processes. This has special implications in understanding and mitigating stress corrosion cracking, a major safety and economic problem in some gas pipelines.

  17. Analytical Investigation for In Situ Stress Measurement with Rheological Stress Recovery Method and Its Application

    Quansheng Liu


    Full Text Available In situ stress is one of the most important parameters in underground engineering. Due to the difficulty and weakness of current stress measurement methods in deep soft rock, a new one, rheological stress recovery (RSR method, to determine three-dimensional stress tensor is developed. It is supposed that rock stresses will recover gradually with time and can be measured by embedding transducers into the borehole. In order to explore the relationship between the measured recovery stress and the initial stress, analytical solutions are developed for the stress measurement process with RSR method in a viscoelastic surrounding rock. The results showed that the measured recovery stress would be more close to the initial stress if the rock mass has a better rheological property, and the property of grouting material should be close to that of rock mass. Then, the RSR method, as well as overcoring technique, was carried out to measure the in situ stresses in Pingdingshan Number 1 coal mines in Henan Province, China. The stress measurement results are basically in the same order, and the major principal stresses are approximately in the direction of NW-SE, which correlates well with the stress regime of Pingdingshan zone known from the tectonic movement history.

  18. Measurements of residual stress in fracture mechanics coupons

    Prime, Michael B [Los Alamos National Laboratory; Hill, Michael R [U.C. DAVIS; Nav Dalen, John E [HILL ENGINEERING


    This paper describes measurements of residual stress in coupons used for fracture mechanics testing. The primary objective of the measurements is to quantify the distribution of residual stress acting to open (and/or close) the crack across the crack plane. The slitting method and the contour method are two destructive residual stress measurement methods particularly capable of addressing that objective, and these were applied to measure residual stress in a set of identically prepared compact tension (C(T)) coupons. Comparison of the results of the two measurement methods provides some useful observations. Results from fracture mechanics tests of residual stress bearing coupons and fracture analysis, based on linear superposition of applied and residual stresses, show consistent behavior of coupons having various levels of residual stress.

  19. Flexible Micropost Arrays for Shear Stress Measurement

    Wohl, Christopher J.; Palmieri, Frank L.; Hopkins, John W.; Jackson, Allen M.; Connell, John W.; Lin, Yi; Cisotto, Alexxandra A.


    Increased fuel costs, heightened environmental protection requirements, and noise abatement continue to place drag reduction at the forefront of aerospace research priorities. Unfortunately, shortfalls still exist in the fundamental understanding of boundary-layer airflow over aerodynamic surfaces, especially regarding drag arising from skin friction. For example, there is insufficient availability of instrumentation to adequately characterize complex flows with strong pressure gradients, heat transfer, wall mass flux, three-dimensionality, separation, shock waves, and transient phenomena. One example is the acoustic liner efficacy on aircraft engine nacelle walls. Active measurement of shear stress in boundary layer airflow would enable a better understanding of how aircraft structure and flight dynamics affect skin friction. Current shear stress measurement techniques suffer from reliability, complexity, and airflow disruption, thereby compromising resultant shear stress data. The state-of-the-art for shear stress sensing uses indirect or direct measurement techniques. Indirect measurements (e.g., hot-wire, heat flux gages, oil interferometry, laser Doppler anemometry, small scale pressure drag surfaces, i.e., fences) require intricate knowledge of the studied flow, restrictive instrument arrangements, large surface areas, flow disruption, or seeding material; with smaller, higher bandwidth probes under development. Direct measurements involve strain displacement of a sensor element and require no prior knowledge of the flow. Unfortunately, conventional "floating" recessed components for direct measurements are mm to cm in size. Whispering gallery mode devices and Fiber Bragg Gratings are examples of recent additions to this type of sensor with much smaller (?m) sensor components. Direct detection techniques are often single point measurements and difficult to calibrate and implement in wind tunnel experiments. In addition, the wiring, packaging, and installation

  20. Experimental Development of a Novel Stress Sensor for in situ Stress Measurement

    Polsky, Yarom [ORNL; Lance, Michael J [ORNL; Mattus, Catherine H [ORNL; Daniels, Ryan J [ORNL


    This paper will describe ongoing work to adapt a previously demonstrated method for measuring stress in ceramics to develop a borehole deployed in situ stress sensor. The method involves the use of a cementitious material which exhibits a strong piezo-spectroscopic stress response as a downhole stress gage. A description of the conceptual approach will be provided along with preliminary analysis and proof-of-concept laboratory results.

  1. Measuring Interlayer Shear Stress in Bilayer Graphene

    Wang, Guorui; Dai, Zhaohe; Wang, Yanlei; Tan, PingHeng; Liu, Luqi; Xu, Zhiping; Wei, Yueguang; Huang, Rui; Zhang, Zhong


    Monolayer two-dimensional (2D) crystals exhibit a host of intriguing properties, but the most exciting applications may come from stacking them into multilayer structures. Interlayer and interfacial shear interactions could play a crucial role in the performance and reliability of these applications, but little is known about the key parameters controlling shear deformation across the layers and interfaces between 2D materials. Herein, we report the first measurement of the interlayer shear stress of bilayer graphene based on pressurized microscale bubble loading devices. We demonstrate continuous growth of an interlayer shear zone outside the bubble edge and extract an interlayer shear stress of 40 kPa based on a membrane analysis for bilayer graphene bubbles. Meanwhile, a much higher interfacial shear stress of 1.64 MPa was determined for monolayer graphene on a silicon oxide substrate. Our results not only provide insights into the interfacial shear responses of the thinnest structures possible, but also establish an experimental method for characterizing the fundamental interlayer shear properties of the emerging 2D materials for potential applications in multilayer systems.

  2. Are the Federal Reserve's Stress Test Results Predictable?

    Paul Glasserman; Gowtham Tangirala


    Regulatory stress tests have become a key tool for setting bank capital levels. Publicly disclosed results for four rounds of stress tests suggest that as the stress testing process has evolved, its outcomes have become more predictable and therefore arguably less informative. In particular, projected stress losses in the 2013 and 2014 stress tests are nearly perfectly correlated for bank holding companies that participated in both rounds. We also compare projected losses across different sce...

  3. Measuring stress variation with depth using Barkhausen signals

    Kypris, O.; Nlebedim, I. C.; Jiles, D. C.


    Magnetic Barkhausen noise analysis (BNA) is an established technique for the characterization of stress in ferromagnetic materials. An important application is the evaluation of residual stress in aerospace components, where shot-peening is used to strengthen the part by inducing compressive residual stresses on its surface. However, the evaluation of the resulting stress-depth gradients cannot be achieved by conventional BNA methods, where signals are interpreted in the time domain. The immediate alternative of using x-ray diffraction stress analysis is less than ideal, as the use of electropolishing to remove surface layers renders the part useless after inspection. Thus, a need for advancing the current BNA techniques prevails. In this work, it is shown how a parametric model for the frequency spectrum of Barkhausen emissions can be used to detect variations of stress along depth in ferromagnetic materials. Proof of concept is demonstrated by inducing linear stress-depth gradients using four-point bending, and fitting the model to the frequency spectra of measured Barkhausen signals, using a simulated annealing algorithm to extract the model parameters. Validation of our model suggests that in bulk samples the Barkhausen frequency spectrum can be expressed by a multi-exponential function with a dependence on stress and depth. One practical application of this spectroscopy method is the non-destructive evaluation of residual stress-depth profiles in aerospace components, thus helping to prevent catastrophic failures.

  4. Exercise-induced dehydration with and without environmental heat stress results in increased oxidative stress.

    Hillman, Angela R; Vince, Rebecca V; Taylor, Lee; McNaughton, Lars; Mitchell, Nigel; Siegler, Jason


    While in vitro work has revealed that dehydration and hyperthermia can elicit increased cellular and oxidative stress, in vivo research linking dehydration, hyperthermia, and oxidative stress is limited. The purpose of this study was to investigate the effects of exercise-induced dehydration with and without hyperthermia on oxidative stress. Seven healthy male, trained cyclists (power output (W) at lactate threshold (LT): 199 ± 19 W) completed 90 min of cycling exercise at 95% LT followed by a 5-km time trial (TT) in 4 trials: (i) euhydration in a warm environment (EU-W, control), (ii) dehydration in a warm environment (DE-W), (iii) euhydration in a thermoneutral environment (EU-T), and (iv) dehydration in a thermoneutral environment (DE-T) (W: 33.9 ± 0.9 °C; T: 23.0 ± 1.0 °C). Oxidized glutathione (GSSG) increased significantly postexercise in dehydration trials only (DE-W: p dehydration trials (p = 0.08 for both). Monocyte heat shock protein 72 (HSP72) concentration was increased (p = 0.01) while lymphocyte HSP32 concentration was decreased for all trials (p = 0.02). Exercise-induced dehydration led to an increase in GSSG concentration while maintenance of euhydration attenuated these increases regardless of environmental condition. Additionally, we found evidence of increased cellular stress (measured via HSP) during all trials independent of hydration status and environment. Finally, both 90-min and 5-km TT performances were reduced during only the DE-W trial, likely a result of combined cellular stress, hyperthermia, and dehydration. These findings highlight the importance of fluid consumption during exercise to attenuate thermal and oxidative stress during prolonged exercise in the heat.

  5. An ultrasonic technique for measuring stress in fasteners

    Stevens, K. J.; Day, P.; Byron, D.


    High temperature bolting alloys are extensively used in the thermal power generation industry as for example, reheat ESV and Governor valve studs. Remnant life assessment methodologies and plant maintenance procedures require the monitoring of the operational stress levels in these fasteners. Some conventional ultrasonic techniques require longitudinal wave measurements to be undertaken when the nut on the bolt is loosened and then re-tightened. Other techniques use a combination of shear waves and longitudinal waves. In this paper, the problems and pitfalls associated with various ultrasonic techniques for measuring stress in bolts, is discussed. An ultrasonic technique developed for measuring the stress in Durehete 1055 bolts is presented. Material from a textured rolled bar has been used as a test bed in the development work. The technique uses shear wave birefringence and compression waves at several frequencies to measure texture, fastener length and the average stress. The technique was developed by making ultrasonic measurements on bolts tensioned in universal testing machines and a hydraulic nut. The ultrasonic measurements of residual stress have been checked against strain gauge measurements. The Durehete bolts have a hollow cylinder geometry of restricted dimensions, which significantly alters compression and shear wave velocities from bulk values and introduces hoop stresses which can be measured by rotating the polarization of the shear wave probe. Modelling of the experimental results has been undertaken using theories for the elastic wave propagation through waveguides. The dispersion equations allow the velocity and length of the fastener to be measured ultrasonically in some situations where the length of the fastener can not be measured directly with a vernier caliper or micrometer and/or where it is undesirable to loosen nuts to take calibration readings of the shear and compression wave velocities.

  6. Soil compaction: Evaluation of stress transmission and resulting soil structure

    Naveed, Muhammad; Schjønning, Per; Keller, Thomas;

    and compaction-resulted soil structure at the same time. Stress transmission was quantified using both X-ray CT and Tactilus sensor mat, and soil-pore structure was quantified using X-ray CT. Our results imply that stress transmission through soil highly depends on the magnitude of applied load and aggregate......, as a result stress transmission mode was shifted from discrete towards more like a continuum. Continuum-like stress transmission mode was better simulated with Boussinesq (1885) model based on theory of elasticity compared to discrete. The soil-pore structure was greatly affected by increasing applied......Accurate estimation of stress transmission and resultant deformation in soil profiles is a prerequisite for the development of predictive models and decision support tools for preventing soil compaction. Numerous studies have been carried out on the effects of soil compaction, whilst relatively few...

  7. Measuring wind and stress under tropical cyclones with scatterometer

    Liu, W. Timothy


    Ocean surface stress, the turbulent transport of momentum, is largely derived from wind through a drag coefficient. In tropical cyclones (TC), scatterometers have difficulty in measuring strong wind and there is large uncertainty in the drag coefficient. We postulate that the microwave backscatter from ocean surface roughness, which is in equilibrium with local stress, does not distinguish weather systems. The reduced sensitivity of scatterometer wind retrieval algorithm under the strong wind is an air-sea interaction problem that is caused by a change in the behavior of the drag coefficient and not a sensor problem. Under this assumption, we applied a stress retrieval algorithm developed over a moderate wind range to retrieve stress under the strong winds of TCs. Over a moderate wind range, the abundant wind measurements and more established drag coefficient value allow sufficient stress data to be computed from wind to develop a stress retrieval algorithm for the scatterometer. Using unprecedented large amount of stress retrieved from the scatterometer coincident with strong winds in TC, we showed that the drag coefficient decreases with wind speed at a much steeper rate than previously revealed, for wind speeds over 25 m/s. The result implies that the ocean applies less drag to inhibit TC intensification and the TC causes less ocean mixing and surface cooling than previous studies indicated. With continuous and extensive coverage from constellations of scatterometers for several decades, the impact of tropical cyclones on the ocean and the feedback from the ocean are examined.

  8. Posttraumatic Stress Disorder Patients and Results of Violent Behavior

    Taner Oznur


    Full Text Available AIM: High levels of anger and aggression in post-traumatic stress disorder lead to unfavorable social, legal, physical and economic results to family members and the other social layers as much as patients. In this study, it is aimed to investigate the relation between both alcohol-cigarette consumption ratios and anger levels, characteristics of aggressive behaviors and the judicial outcome in cases diagnosed post-traumatic stress disorder due to armed conflict. METHODS: 38 cases diagnosed as post-traumatic stress disorder were included to the study. Pre- and post-traumatic alcohol/cigarette consumption amounts and aggressive behaviors are determined. Impact of Events Scale (Revised (IES-R was used for evaluating post-traumatic stress disorder symptom patterns and severity, Buss Perry Aggression Questionnaire was used for measuring anger and aggression levels, and Taylor and #8217;s Violence Rating Scale was used for evaluating the judicial outcome of aggression. RESULTS: 23 of cases (60.6% were married with children, 13 of cases (34.25 were single and 2 of cases (5.2% were divorced.18 of cases (47.4% were graduate. IES-R total score was 66,9 +/- 12,7, Buss Perry total score was 111,3 +/- 20,5, and Taylor and #8217;s Violence Rate was 2,5 +/- 1,0. When the pre- and post-traumatic aggressive behaviors were compared; physical violence to the partner was increased more than ten times, Physical and verbal violence to social individuals were increased more than four and seven times, respectively. And also it is observed that inflicting damage to property was increased 17 times, reckless driving was increased 11 times, and self-mutilation was increased 5 times. Alcohol consumption was determined as 0 (0 - 126 g/day for pre-trauma cases and 16.5 (0 - 294 g/day for post-trauma cases. Cigarette smoking was determined as 5 (0 and #8211; 40 cigarette/day for pre-trauma cases and 30 (0 -60 cigarette/day for post-trauma cases. CONCLUSION: Post

  9. Towards ambulatory mental stress measurement from physiological parameters

    Wijsman, J.L.P; Vullers, Ruud; Polito, Salvatore; Agell, Carlos; Penders, Julien; Hermens, Hermanus J.

    Ambulatory mental stress monitoring requires longterm physiological measurements. This paper presents a data collection protocol for ambulatory recording of physiological parameters for stress measurement purposes. We present a wearable sensor system for ambulatory recording of ECG, EMG, respiration

  10. Towards ambulatory mental stress measurement from physiological parameters

    Wijsman, Jacqueline; Vullers, Ruud; Polito, Salvatore; Agell, Carlos; Penders, Julien; Hermens, Hermie


    Ambulatory mental stress monitoring requires longterm physiological measurements. This paper presents a data collection protocol for ambulatory recording of physiological parameters for stress measurement purposes. We present a wearable sensor system for ambulatory recording of ECG, EMG, respiration

  11. Phase stress measurements in composite materials

    Akiniwa, Yoshiaki; Tanaka, Keisuke [Nagoya Univ. (Japan). School of Engineering


    Using an aluminum alloy composite containing 20 wt.% of SiC powder and an aluminum alloy itself, a phase stress under monoaxial tensile load was tested using x-ray and neutron methods, to compare both of them. For specimens, a 20 vol.% SiC powder reinforced aluminum alloy and an aluminum alloy itself were used. As a result, the following results could be obtained. Young`s modulus and Poisson ratio of the aluminum alloy itself using x-ray method were E=74.5 GPa and {nu}=0.312, respectively, and those using neutron method were E=75.3 GPa and {nu}=0.384, respectively. A relationship between loading stress and lattice strain of the aluminum alloy itself using neutron method was possible to approximate linearly by containing macroscopic plastic deformation region. The lattice strain of each phase in the composite increased proportionally with loading stress in its elastic region, but when remarkably increasing plastic deformation, the lattice strain decreased proportionally in aluminum phase and increased in SiC phase. (G.K.)

  12. Measurement of probability distributions for internal stresses in dislocated crystals

    Wilkinson, Angus J.; Tarleton, Edmund; Vilalta-Clemente, Arantxa; Collins, David M. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Jiang, Jun; Britton, T. Benjamin [Department of Materials, Imperial College London, Royal School of Mines, Exhibition Road, London SW7 2AZ (United Kingdom)


    Here, we analyse residual stress distributions obtained from various crystal systems using high resolution electron backscatter diffraction (EBSD) measurements. Histograms showing stress probability distributions exhibit tails extending to very high stress levels. We demonstrate that these extreme stress values are consistent with the functional form that should be expected for dislocated crystals. Analysis initially developed by Groma and co-workers for X-ray line profile analysis and based on the so-called “restricted second moment of the probability distribution” can be used to estimate the total dislocation density. The generality of the results are illustrated by application to three quite different systems, namely, face centred cubic Cu deformed in uniaxial tension, a body centred cubic steel deformed to larger strain by cold rolling, and hexagonal InAlN layers grown on misfitting sapphire and silicon carbide substrates.

  13. Measurement of residual stresses using fracture mechanics weight functions

    Fan, Y. [Bettis Atomic Power Laboratory, West Mifflin, PA (United States)


    A residual stress measurement method has been developed to quantify through-the-thickness residual stresses. Accurate measurement of residual stresses is crucial for many engineering structures. Fabrication processes such as welding and machining generate residual stresses that are difficult to predict. Residual stresses affect the integrity of structures through promoting failures due to brittle fracture, fatigue, stress corrosion cracking, and wear. In this work, the weight function theory of fracture mechanics is used to measure residual stresses. The weight function theory is an important development in computational fracture mechanics. Stress intensity factors for arbitrary stress distribution on the crack faces can be accurately and efficiently computed for predicting crack growth. This paper demonstrates that the weight functions are equally useful in measuring residual stresses. In this method, an artificial crack is created by a thin cut in a structure containing residual stresses. The cut relieves the residual stresses normal to the crack-face and allows the relieved residual stresses to deform the structure. Strain gages placed adjacent to the cut measure the relieved strains corresponding to incrementally increasing depths of the cut. The weight functions of the cracked body relate the measured strains to the residual stresses normal to the cut within the structure. The procedure details, such as numerical integration of the singular functions in applying the weight function method, will be discussed. (author)

  14. Improving Earthquake Stress Drop Measurements - What can we Really Resolve?

    Abercrombie, R. E.; Bannister, S. C.; Fry, B.; Ruhl, C. J.; Kozlowska, M.


    Earthquake stress drop is fundamental to understanding the physics of the rupture process. Although it is superficially simple to calculate an estimate of stress drop from the corner frequency of the radiated spectrum, it is much harder to be certain that measurements are reliable and accurate. The same is true of other measurements of stress drop and radiated energy. The large number of studies of earthquake stress drop, the high variability in results (~0.1-100 MPa), the large uncertainties, and the ongoing scaling controversy are evidence for this. We investigate the resolution and uncertainties of stress drops calculated using an empirical Green's function (EGF) approach. Earthquakes in 3 sequences at Parkfield, California are recorded by multiple borehole stations and have abundant smaller earthquakes to use as EGFs (Abercrombie, 2014). The earthquakes in the largest magnitude cluster (M~2.1) exhibit clear temporal variation of stress drop. Independent studies obtained a similar pattern implying that it is resolvable for these well-recorded, simple sources. The borehole data reveal a similar temporal pattern for another sequence, not resolvable in an earlier study using surface recordings. The earthquakes in the third sequence have complex sources; corner frequency measurements for this sequence are highly variable and poorly resolved. We use the earthquakes in the first cluster to quantify the uncertainties likely to arise in less optimal settings. The limited signal bandwidth and the quality of the EGF assumption are major sources of error. Averaging across multiple stations improves the resolution, as does using multiple good EGFs (Abercrombie, 2015). We adapt the approach to apply to larger data sets. We focus on New Zealand, with the aim of resolving stress drop variability in a variety of tectonic settings. We investigate stacking over stations and multiple EGFs, and compare earthquakes (M~3-6) from both the overlying and the subducting plates.

  15. Realtime 3D stress measurement in curing epoxy packaging

    Richter, Jacob; Hyldgård, A.; Birkelund, Karen;


    This paper presents a novel method to characterize stress in microsystem packaging. A circular p-type piezoresistor is implemented on a (001) silicon chip. We use the circular stress sensor to determine the packaging induced stress in a polystyrene tube filled with epoxy. The epoxy curing process...... is monitored by stress measurements. From the stress measurements we conclude that the epoxy cures in 8 hours at room temperature. We find the difference in in-plane normal stresses to be sigmaxx-sigmayy=6.7 MPa and (sigmaxx+sigmayy-0.4sigmazz)=232 MPa....

  16. Measuring Stress Distributions of Orthotropic Composite Material in Plane Stress State by the Lock-in Infrared Thermography Technique

    LI Xu-Dong; WANG Wei-Bo; LI Yong-Sheng; WU Dong-Liu


    Feasibility of measuring stress distributions of orthotropic composite materials and structures in plane stress state by the lock-in infrared thermography technique is analyzed and stress distributions of a lap joint structure made of a kind of glass reinforced plastic composite lamination plates under tensile loadings are obtained by the lock-in infrared thermography technique. Feasibility and credibility of using this technique to measure stress distributions of orthotropic composite materials and structures in plane stress state are proved by comparing the results with the data given by the digital speckle correlation method.%@@ Feasibility of measuring stress distributions of orthotropic composite materials and structures in plane stress state by the lock-in infrared thermography technique is analyzed and stress distributions of a lap joint structure made of a kind of glass reinforced plastic composite lamination plates under tensile loadings axe obtained by the lock-in infrared thermography technique.Feasibility and credibility of using this technique to measure stress distributions of orthotropic composite materials and structures in plane stress state axe proved by comparing the results with the data given by the digital speckle correlation method.

  17. Principles of the measurement of residual stress by neutron diffraction

    Webster, G.A.; Ezeilo, A.N. [Imperial Coll. of Science and Technology, London (United Kingdom). Dept. of Mechanical Engineering


    The presence of residual stresses in engineering components can significantly affect their load carrying capacity and resistance to fracture. In order to quantify their effect it is necessary to know their magnitude and distribution. Neutron diffraction is the most suitable method of obtaining these stresses non-destructively in the interior of components. In this paper the principles of the technique are described. A monochromatic beam of neutrons, or time of flight measurements, can be employed. In each case, components of strain are determined directly from changes in the lattice spacings between crystals. Residual stresses can then be calculated from these strains. The experimental procedures for making the measurements are described and precautions for achieving reliable results discussed. These include choice of crystal planes on which to make measurements, extent of masking needed to identify a suitable sampling volume, type of detector and alignment procedure. Methods of achieving a stress free reference are also considered. A selection of practical examples is included to demonstrate the success of the technique. (author) 14 figs., 1 tab., 18 refs.

  18. Demystifying Results-Based Performance Measurement.

    Jorjani, Hamid

    Many evaluators are convinced that Results-based Performance Measurement (RBPM) is an effective tool to improve service delivery and cost effectiveness in both public and private sectors. Successful RBPM requires self-directed and cross-functional work teams and the supporting infrastructure to make it work. There are many misconceptions and…

  19. Initial Results from the New Stress Map of Texas Project

    Lund Snee, J. E.; Zoback, M. D.


    Modern techniques for characterizing tectonic stress orientation and relative magnitude have been successfully used for more than 35 years. Nevertheless, large areas of North America lack high spatial resolution maps of stress orientation, magnitude, and faulting regime. In Texas, for example, geothermal resources. This year, we launched the Texas Stress Map project to characterize tectonic stress patterns at higher spatial resolution across Texas and nearby areas. Following a successful effort just completed in Oklahoma, we will evaluate borehole breakouts, drilling-induced tensile fractures, shear wave anisotropy, and earthquake data. The principal data source will be FMI (fullbore formation microimager), UBI (ultrasonic borehole imager), cross-dipole sonic, density, and caliper logs provided by private industry. Earthquake moment tensor solutions from the U.S. Geological Survey, Saint Louis University and other sources will also be used. Our initial focus is on the Permian Basin and Barnett Shale petroleum plays due to the availability of data, but we will expand our analysis across the state as the project progresses. In addition, we hope to eventually apply the higher spatial resolution data coverage to understanding tectonic and geodynamic characteristics of the southwestern United States and northeastern Mexico. Here we present early results from our work to constrain stress orientations and faulting regime in and near Texas, and we also provide a roadmap for the ongoing research.

  20. Measuring type II stresses using 3DXRD

    Oddershede, Jette; Schmidt, Søren; Poulsen, Henning Friis;


    An algorithm is presented for characterization of the grain resolved (type II) stress states in a polycrystalline sample based on monochromatic X-ray diffraction data. The algorithm is a robust 12-parameter-per-grain fit of the centre-of-mass grain positions, orientations and stress tensors...

  1. Comet assay as an indirect measure of systemic oxidative stress.

    Fang, Lei; Neutzner, Albert; Turtschi, Stephanie; Flammer, Josef; Mozaffarieh, Maneli


    Higher eukaryotic organisms cannot live without oxygen; yet, paradoxically, oxygen can be harmful to them. The oxygen molecule is chemically relatively inert because it has two unpaired electrons located in different pi * anti-bonding orbitals. These two electrons have parallel spins, meaning they rotate in the same direction about their own axes. This is why the oxygen molecule is not very reactive. Activation of oxygen may occur by two different mechanisms; either through reduction via one electron at a time (monovalent reduction), or through the absorption of sufficient energy to reverse the spin of one of the unpaired electrons. This results in the production of reactive oxidative species (ROS). There are a number of ways in which the human body eliminates ROS in its physiological state. If ROS production exceeds the repair capacity, oxidative stress results and damages different molecules. There are many different methods by which oxidative stress can be measured. This manuscript focuses on one of the methods named cell gel electrophoresis, also known as "comet assay" which allows measurement of DNA breaks. If all factors known to cause DNA damage, other than oxidative stress are kept constant, the amount of DNA damage measured by comet assay is a good parameter of oxidative stress. The principle is simple and relies upon the fact that DNA molecules are negatively charged. An intact DNA molecule has such a large size that it does not migrate during electrophoresis. DNA breaks, however, if present result in smaller fragments which move in the electrical field towards the anode. Smaller fragments migrate faster. As the fragments have different sizes the final result of the electrophoresis is not a distinct line but rather a continuum with the shape of a comet. The system allows a quantification of the resulting "comet" and thus of the DNA breaks in the cell.

  2. A Hydraulic Stress Measurement System for Deep Borehole Investigations

    Ask, Maria; Ask, Daniel; Cornet, Francois; Nilsson, Tommy


    present this new and unique stress measurement system and some initial test results from a 1200 m long borehole in crystalline rock.

  3. Galvanic Skin Response as a Measure of Soldier Stress


    in the body have been used as an effective measure of stress, including social stress such as performance in front of an audience (Nater, La Marca ...Lake, CA, 1992. Nater, U. M.; La Marca , R.; Florin, L.; Moses, A.; Langhans, W.; Koller, M. M.; Ehlert, U. Stress-Induced Changes in Human

  4. The Difficult Patient Stress Scale: a new instrument to measure interpersonal stress in nursing.

    Santamaria, N


    This study describes the development of the Difficult Patient Stress Scale, an instrument designed to investigate the stress that nurses experience when they are involved in interpersonal conflict with patients. The DPSS is based on the theoretical conceptualization of stress proposed by DeLongis, Lazarus and Folkman and on the personality theory of Individual Psychology. The DPSS utilises visual analog scales to measure nurses' responses to hypothetical scenarios that present typical, difficult nurse-patient situations. The DPSS has been tested over a period of two years with 228 nurses and the results to date indicate that it is valid, reliable and suitable for use in the clinical environment. It is proposed that it may provide a useful instrument for exploring the impact and frequency of interpersonal stressors in nursing and may assist in the development of educational programs to better equip nurses to deal with interpersonal nurse-patient conflict.

  5. Residual strain change resulting from stress corrosion in Carrara marble

    Voigtlaender, Anne; Leith, Kerry; Krautblatter, Michael


    Residual stresses and strains have been shown to play a fundamental role in determining the elastic behavior of engineering materials, yet the effect of these strains on brittle and elastic behavior of rocks remains unclear. In order to evaluate the impact of stored elastic strains on fracture propagation in rock, we undertook a four-month-long three-point bending test on three large 1100 x 100 x 100 mm Carrara Marble samples. This test induced stable low stress conditions in which strains were concentrated at the tip of a saw cut and pre-cracked notch. A corrosive environment was created at the tip of the notch on two samples (M2 and M4) by dripping calcite saturated water (pH ~ 7.5-8). Sample M5 was loaded in the same way, but kept dry. Samples were unloaded prior to failure, and along with an additional non-loaded reference sample (M0), cored into cylindrical subsamples (ø = 50 mm, h = 100 mm) before being tested for changes in residual elastic strains at the SALSA neutron diffractometer at the Institute Laue-Langevin (ILL), Grenoble, France. Three diffraction peaks corresponding to crystallographic planes hkl (110), (104) and (006) were measured in all three spatial directions relative to the notch. Shifts in the diffraction peak position (d) with respect to a strain free state are indicative of intergranular strain, while changes in the width of the peak (FWHM) reflect changes in intragranular strain. We observe distinctly different patterns in residual and volumetric strains in hkℓ (104) and (006) for the dry M5 and wet tested samples (M2 and M4) indicating the presence of water changes the deformation mechanism, while (110) is strained in compression around 200 μstrain in all samples. A broadening of the diffraction peaks (006) and (110) in front of the crack tip is observed in M2 and M4, while M5 shows no changes in the peak width throughout the depth of the sample. We suggest water present at the crack tip increased the rate of corrosion, allowing a

  6. Axillary temperature measurement: a less stressful alternative for hospitalised cats?

    Girod, M; Vandenheede, M; Farnir, F; Gommeren, K


    Rectal temperature measurement (RTM) can promote stress and defensive behaviour in hospitalised cats. The aim of this study was to assess if axillary temperature measurement (ATM) could be a reliable and less stressful alternative for these animals. In this prospective study, paired rectal and axillary temperatures were measured in 42 cats, either by a veterinarian or a student. To assess the impact of these procedures on the cat's stress state, their heart rate was checked and a cat stress score (CSS) was defined and graded from 1 (relaxed) to 5 (terrified). A moderate correlation was found between RTM and ATM (r=0.52; Pcats.

  7. A Study on Reynolds Shear Stress Measurement by LDV

    Mizue Munekata; Hideki Ohba; Kazuyoshi Matsuzaki


    The measurement results by Laser Doppler Velocimetry (LDV) are compared with the direct numerical simulation result by Eggels et al.[1] for a cylindrical pipe flow. In the case of a pipe flow, the bias error for mean velocity is very small, because the local turbulent intensity is very small all over the pipe cross section. However the difference of the combination of u' and v' have considerable effects on Reynolds shear stress. From our investigation, it is found that the selection of coincidence time that is a necessary parameter for combination of u' and v' is more important in obtaining the accurate Reynolds shear stress. The suitable coincidence time is selected for a jet flow and the effectiveness of coincident time method or equal time interval method with coincidence data is shown.

  8. Developments in wireline in-situ rock stress measurement

    Pedroso, Carlos [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Canas, Jesus A.; Holzberg, Bruno; Gmach, Helmut [Schlumberger Servicos de Petroleo Ltda., Rio de Janeiro, RJ (Brazil)


    This paper presents recent developments of in-situ stress measurements with wireline tools. The stress measurements are based on the micro hydraulic techniques that can be initialized when an interval is pressurized by pumping fluid until a tensile fracture begins or by packers fracturing (sleeve fracturing). Ultrasonic and Micro-resistivity borehole image logs (before and after the testes) are used as a complement, in order to observe the fractures created by the tests, evaluating the mechanical behavior of the formation. An offshore case study is presented, where shales and tight sandstones at depths deeper than 4500 meters depth were successfully evaluated. A workflow to succeed on stress measurements on such environments is proposed, what includes a planning phase: where breakdown pressures ranges are estimated and compared with the capacity of the tools, a Real Time Monitoring phase, where a decision tree is proposed to help on quick decisions while testing, and an interpretation phase, where appropriate techniques are indicated to evaluate the results. Also, the paper presents the main operational needs to succeed on such environments. Basically, such tests require an entirely software controlled, motorized and modular design tool consisting of dual packer (DP), pump out and flow control modules (Figure 1). These modules were upgraded for the present environment: conditions such as temperatures above 300 deg F, formation pressures above 10,000 psia, very low formation permeability, high pressure differential need and oil based mud (OBM) environment. (author)

  9. StressPhone: smartphone based platform for measurement of cortisol for stress detection (Conference Presentation)

    Jain, Aadhar; Rey, Elizabeth; Lee, Seoho; O'Dell, Dakota; Erickson, David


    Anxiety disorders are estimated to be the most common mental illness in US affecting around 40 million people and related job stress is estimated to cost US industry up to $300 billion due to lower productivity and absenteeism. A personal diagnostic device which could help identify stressed individuals would therefore be a huge boost for workforce productivity. We are therefore developing a point of care diagnostic device that can be integrated with smartphones or tablets for the measurement of cortisol - a stress related salivary biomarker, which is known to be strongly involved in body's fight-or-flight response to a stressor (physical or mental). The device is based around a competitive lateral flow assay whose results can then be read and quantified through an accessory compatible with the smartphone. In this presentation, we report the development and results of such an assay and the integrated device. We then present the results of a study relating the diurnal patterns of cortisol levels and the alertness of an individual based on the circadian rhythm and sleep patterns of the individual. We hope to use the insight provided by combining the information provided by levels of stress related to chemical biomarkers of the individual with the physical biomarkers to lead to a better informed and optimized activity schedule for maximized work output.

  10. Pulsed eddy current and ultrasonic data fusion applied to stress measurement

    Habibalahi, A.; Safizadeh, M. S.


    Stress measurement and its variation are key problems in the operating performance of materials. Stress can affect the material properties and the life of components. There are several destructive and nondestructive techniques that are used to measure stress. However, no single nondestructive testing (NDT) technique or method is satisfactory to fully assess stress. This paper presents an NDT data fusion method to improve stress measurement. An aluminum alloy 2024 specimen subjected to stress simulation is nondestructively inspected using pulsed eddy current and ultrasonic techniques. Following these nondestructive examinations, the information gathered from these two NDT methods has been fused using a suitable fuzzy combination operator. The results obtained with these processes are presented in this paper and their efficiency is discussed. It is shown that the fusion of NDT data with a suitable fuzzy operator can be adequate to improve the reliability of stress measurements.

  11. Stress Resultant Based Elasto-Viscoplastic Thick Shell Model

    Pawel Woelke


    Full Text Available The current paper presents enhancement introduced to the elasto-viscoplastic shell formulation, which serves as a theoretical base for the finite element code EPSA (Elasto-Plastic Shell Analysis [1–3]. The shell equations used in EPSA are modified to account for transverse shear deformation, which is important in the analysis of thick plates and shells, as well as composite laminates. Transverse shear forces calculated from transverse shear strains are introduced into a rate-dependent yield function, which is similar to Iliushin's yield surface expressed in terms of stress resultants and stress couples [12]. The hardening rule defined by Bieniek and Funaro [4], which allows for representation of the Bauschinger effect on a moment-curvature plane, was previously adopted in EPSA and is used here in the same form. Viscoplastic strain rates are calculated, taking into account the transverse shears. Only non-layered shells are considered in this work.

  12. Measurement of Residual Stress in a Welded Branch Connection and Effects on Fracture Behaviour

    Law, M.; Luzin, V.; Kirstein, O.


    The branch analysed in this paper was not post weld heat treated, resulting in significant residual stresses. Assessment codes assume these to be at, or close to, yield. An integrity assessment of a welded branch connection was carried out using these high assumed residual stresses. The weld then had residual stresses determined by neutron diffraction, performed using ANSTO's residual stress diffractometer, Kowari. The maximum measured residual stress (290 MPa or 60% of yield) was much lower than the yield value assumed by assessment codes. Reanalysing with the actual residual stresses almost doubled the critical crack size, increasing the safety of the connection.

  13. The measurement of in situ stress using NQR/NMR

    Schempp, E.; Murdoch, J. B.; Klainer, S. M.


    The measurement of stress in rocks underground is a difficult but very important problem in mining engineering and in the design of underground waste repositories. The structural stability of any excavation is critically dependent on the stress distribution in the surrounding rock and its capability to bear the stress, which can build up to hundreds of atmospheres in deep mines. Because existing methods for the determination of stress have limitations, Lawrence Berkeley Laboratory (LBL) has been investigating the use of spectroscopic techniques - nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) - for rapid in situ measurements of three-dimensional stress in both salt and hard rock. Efforts in the past year have been directed toward computer simulation of boreholes stress patterns and NQR lineshapes, laboratory measurements on salt and aluminosilicates, and construction of a state-of-the-art pulsed NQR spectrometer.

  14. Measurment Of Residual Stress In Ferromagnetic Materials

    Namkung, Min; Yost, William T.; Kushnick, Peter W.; Grainger, John L.


    Magnetoacoustic (MAC) and magnetoacoustic emission (MAE) techniques combined to provide complete characterization of residual stresses in ferromagnetic structural materials. Combination of MAC and MAE techniques makes it possible to characterize residual tension and compression without being limited by surface conditions and unavailability of calibration standards. Significant in field of characterization of materials as well as detection of fatigue failure.

  15. Local residual stress measurements on nitride layers

    Mansilla, C.; Ocelik, V.; De Hosson, J. Th. M.


    In this work, local stresses in different nitrided maraging steel samples of high practical interest for industrial applications were studied through the so-called micro-slit milling method using a focused ion beam. The nitrogen concentration profiles were acquired by glow discharge optical emission

  16. Measurment Of Residual Stress In Ferromagnetic Materials

    Namkung, Min; Yost, William T.; Kushnick, Peter W.; Grainger, John L.


    Magnetoacoustic (MAC) and magnetoacoustic emission (MAE) techniques combined to provide complete characterization of residual stresses in ferromagnetic structural materials. Combination of MAC and MAE techniques makes it possible to characterize residual tension and compression without being limited by surface conditions and unavailability of calibration standards. Significant in field of characterization of materials as well as detection of fatigue failure.

  17. Investigations of some rock stress measuring techniques and the stress field in Norway

    Hanssen, Tor Harald


    Rock stresses are important to the safe construction and operation of all man-made structures in rock, whether In mining, civil or petroleum engineering. The crucial issue is their relative magnitude and orientation. This thesis develops equipment and methods for further rock stress assessment and reevaluates existing overcoring rock stress measurements, and relates this information to the present geological setting. Both laboratory work and field work are involved. In the field, rock stresses are measured by the overcoring and the hydraulic fracturing technique. An observation technique for assessing likely high stresses is developed. The field data refer to several hydropower projects and to some offshore hydrocarbon fields. The principal sections are: (1) Tectonic setting in the western Fennoscandia, (2) Triaxial rock stress measurements by overcoring using the NTH cell (a strain gauge cell developed at the Norwegian technical university in Trondheim and based on the CSIR cell of the South African Council for Scientific and Industrial Research), (3) Laboratory testing of the NTH cell, (4) Quality ranking of stresses measured by the NTH cell, (4) Recalculated rock stresses and implications to the regional stress field, (5) Hydraulic fracturing stress measurements. 113 refs., 98 figs., 62 tabs.

  18. How to measure prenatal stress? A systematic review of psychometric instruments to assess psychosocial stress during pregnancy.

    Nast, Irina; Bolten, Margarete; Meinlschmidt, Gunther; Hellhammer, Dirk H


    A growing body of literature documents associations of maternal psychosocial stress during pregnancy with fetal, infant and child behaviour and development. However, findings across studies are often inconsistent, which may in part be due to differences in stress definitions and assessments. We systematically reviewed methods applied to assess maternal psychosocial stress during pregnancy in studies looking at associations with biobehavioural outcomes in the offspring. A systematic literature search was performed on Web of Science and PubMed for the time period between January 1999 and October 2009. Psychometric instruments assessing maternal psychosocial stress during pregnancy were identified and described if data on psychometric properties were available. We identified 115 publications that assessed psychosocial stress during pregnancy with validated methods. These publications applied overall 43 different instruments assessing constructs falling under seven categories, ordered according to their frequency of use: anxiety, depression, daily hassles, aspects of psychological symptomatology (not reduced to anxiety or depression), life events, specific socio-environmental stressors and stress related to pregnancy and parenting. If available, we provide information on validity and reliability of the instruments for samples of pregnant women. Within the 'prenatal stress' research, a broad range of instruments is applied to assess psychosocial stress during pregnancy. Prenatal stress research should take into consideration that the variety of methods in use might hamper the comparability of stress research results. In each category of stress constructs, one instrument with good psychometric properties in pregnant women is highlighted as the best currently available measure. © 2013 John Wiley & Sons Ltd.

  19. Final Report: Geothermal dual acoustic tool for measurement of rock stress

    Normann, Randy A. [Perma Works LLC, Pattonville, TX (United States)


    This paper outlines the technology need for a rock formation stress measurement in future EGS wells. This paper reports on the results of work undertaken under a Phase I, DOE/SBIR on the feasibility to build an acoustic well logging tool for measuring rock formation stress.

  20. Final Report. Geothermal Dual Acoustic Tool for Measurement of Rock Stress

    Normann, Randy A [Perma Works LLC, Pattonville, TX (United States)


    This paper outlines the technology need for a rock formation stress measurement in future EGS wells. This paper reports on the results of work undertaken under a Phase I, DOE/SBIR on the feasibility to build an acoustic well logging tool for measuring rock formation stress.

  1. Final Report: Geothermal Dual Acoustic Tool for Measurement of Rock Stress

    Normann, Randy A.


    This paper outlines the technology need for a rock formation stress measurement in future EGS wells. This paper reports on the results of work undertaken under a Phase I, DOE/SBIR on the feasibility to build an acoustic well logging tool for measuring rock formation stress.

  2. Residual Stress Measurements After Proof and Flight: ETP-0403

    Webster, Ronald L..


    The intent of this testing was to evaluate the residual stresses that occur in and around the attachment details of a case stiffener segment that has been subjected to flight/recovery followed by proof loading. Not measured in this test were stresses relieved at joint disassembly due to out-of-round and interference effects, and those released by cutting the specimens out of the case segment. The test article was lightweight case stiffener segment 1U50715, S/N L023 which was flown in the forward stiffener position on flight SRM 14A and in the aft position on flight SRM24A. Both of these flights were flown with the 3 stiffener ring configuration. Stiffener L023 had a stiffener ring installed only on the aft stub in its first flight, and it had both rings installed on its second flight. No significant post flight damage was found on either flight. Finally, the segment was used on the DM-8 static test motor in the forward position. No stiffener rings were installed. It had only one proof pressurization prior to assignment to its first use, and it was cleaned and proof tested after each flight. Thus, the segment had seen 3 proof tests, two flight pressurizations, and two low intensity water impacts prior to manufacturing for use on DM-8. On DM-8 it received one static firing pressurization in the horizontal configuration. Residual stresses at the surface and in depth were evaluated by both the x-ray diffraction and neutron beam diffraction methods. The x-ray diffraction evaluations were conducted by Technology for Energy Corporation (TEC) at their facilities in Knoxville, TN. The neutron beam evaluations were done by Atomic Energy of Canada Limited (AECL) at the Chalk River Nuclear Laboratories in Ontario. The results showed general agreement with relatively high compressive residual stresses on the surface and moderate to low subsurface tensile residual stresses.

  3. In-situ stress measurements and stress change monitoring to monitor overburden caving behaviour and hydraulic fracture pre-conditioning

    Puller Jesse W.; Mills Ken W.; Jeffrey Rob G.; Walker Rick J.


    A coal mine in New South Wales is longwall mining 300 m wide panels at a depth of 160–180 m directly below a 16–20 m thick conglomerate strata. As part of a strategy to use hydraulic fracturing to manage potential windblast and periodic caving hazards associated with these conglomerate strata, the in-situ stresses in the conglomerate were measured using ANZI strain cells and the overcoring method of stress relief. Changes in stress associated with abutment loading and placement of hydraulic fractures were also measured using ANZI strain cells installed from the surface and from underground. Overcore stress mea-surements have indicated that the vertical stress is the lowest principal stress so that hydraulic fractures placed ahead of mining form horizontally and so provide effective pre-conditioning to promote caving of the conglomerate strata. Monitoring of stress changes in the overburden strata during longwall retreat was undertaken at two different locations at the mine. The monitoring indicated stress changes were evi-dent 150 m ahead of the longwall face and abutment loading reached a maximum increase of about 7.5 MPa. The stresses ahead of mining change gradually with distance to the approaching longwall and in a direction consistent with the horizontal in-situ stresses. There was no evidence in the stress change monitoring results to indicate significant cyclical forward abutment loading ahead of the face. The for-ward abutment load determined from the stress change monitoring is consistent with the weight of over-burden strata overhanging the goaf indicated by subsidence monitoring.

  4. Recent results on Electroweak measurements from ATLAS

    Benekos Nektarios Chr.


    Full Text Available ATLAS measurements of multiboson production processes involving combinations of W,Z and isolated photons are summarized. Measurements using data at 7 TeV and at 8 TeV are presented. The measurements are performed using leptonic decay modes, including the invisible decay Z → v v̅, as well as semileptonic channels. Measurements of single and diboson production in association with two forward jets is sensitive to electroweak vector boson fusion and scattering processes. An observation of the electroweak production of the Z boson and an evidence of same sign WW production are reported.

  5. Measuring depth profiles of residual stress with Raman spectroscopy

    Enloe, W.S.; Sparks, R.G.; Paesler, M.A.


    Knowledge of the variation of residual stress is a very important factor in understanding the properties of machined surfaces. The nature of the residual stress can determine a part`s susceptibility to wear deformation, and cracking. Raman spectroscopy is known to be a very useful technique for measuring residual stress in many materials. These measurements are routinely made with a lateral resolution of 1{mu}m and an accuracy of 0.1 kbar. The variation of stress with depth; however, has not received much attention in the past. A novel technique has been developed that allows quantitative measurement of the variation of the residual stress with depth with an accuracy of 10nm in the z direction. Qualitative techniques for determining whether the stress is varying with depth are presented. It is also demonstrated that when the stress is changing over the volume sampled, errors can be introduced if the variation of the stress with depth is ignored. Computer aided data analysis is used to determine the depth dependence of the residual stress.

  6. Numerical and experimental demonstration of shear stress measurement at thick steel plates using acoustoelasticity

    Abbasi, Zeynab; Ozevin, Didem


    The purpose of this article is to numerically quantify the stress state of complex loaded thick steel plates using the fundamental theory of acoustoelasticity, which is the relationship with stress and ultrasonic velocity in the nonlinear regime. The normal and shear stresses of a thick plate can be measured using a phased array placement of ultrasonic sensors and Rayleigh ultrasonic waves. Three measurement angles (i.e., 0 45 and 90 degrees) are selected since three measurements are needed to solve the stress tensor in an isotropic plate. The ultrasonic data is influenced significantly by the frequency of the Rayleigh waves as well as the thickness of the plate being examined; consequently the overall experimental process is influenced by the measurement parameters. In this study, a numerical demonstration is implemented to extract the nonlinearity coefficients using a 3D structural geometry and Murnaghan material model capable of examining the effects of various plate thicknesses and ultrasonic frequencies on the shear stress measurement. The purpose is that as the thickness becomes smaller, the shear stress becomes negligible at the angled measurement. For thicker cross section, shear stress becomes influential if the depth of penetration of Rayleigh wave is greater than the half of the thickness. The correlation between the depth of penetration and shear stress is then obtained. The numerical results are compared with 1 MHz ultrasonic frequency and a 3/8 inch thick steel plate loaded uniaxially while the measurement direction is angled to have the presence of shear stress in the measurement direction.

  7. Stress measurement in thick plates using nonlinear ultrasonics

    Abbasi, Zeynab, E-mail:, E-mail:; Ozevin, Didem, E-mail:, E-mail: [University of Illinois at Chicago, Civil and Materials Engineering, 842 W Taylor Street ERF 2095, Chicago, IL 60607 (United States)


    In this paper the interaction between nonlinear ultrasonic characteristics and stress state of complex loaded thick steel plates using fundamental theory of nonlinear ultrasonics is investigated in order to measure the stress state at a given cross section. The measurement concept is based on phased array placement of ultrasonic transmitter-receiver to scan three angles of a given cross section using Rayleigh waves. The change in the ultrasonic data in thick steel plates is influenced by normal and shear stresses; therefore, three measurements are needed to solve the equations simultaneously. Different thickness plates are studied in order to understand the interaction of Rayleigh wave penetration depth and shear stress. The purpose is that as the thickness becomes smaller, the shear stress becomes negligible at the angled measurement. For thicker cross section, shear stress becomes influential if the depth of penetration of Rayleigh wave is greater than the half of the thickness. The influences of plate thickness and ultrasonic frequency on the identification of stress tensor are numerically studied in 3D structural geometry and Murnaghan material model. The experimental component of this study includes uniaxial loading of the plate while measuring ultrasonic wave at three directions (perpendicular, parallel and angled to the loading direction). Instead of rotating transmitter-receiver pair for each test, a device capable of measuring the three angles is designed.

  8. Stress measurement in thick plates using nonlinear ultrasonics

    Abbasi, Zeynab; Ozevin, Didem


    In this paper the interaction between nonlinear ultrasonic characteristics and stress state of complex loaded thick steel plates using fundamental theory of nonlinear ultrasonics is investigated in order to measure the stress state at a given cross section. The measurement concept is based on phased array placement of ultrasonic transmitter-receiver to scan three angles of a given cross section using Rayleigh waves. The change in the ultrasonic data in thick steel plates is influenced by normal and shear stresses; therefore, three measurements are needed to solve the equations simultaneously. Different thickness plates are studied in order to understand the interaction of Rayleigh wave penetration depth and shear stress. The purpose is that as the thickness becomes smaller, the shear stress becomes negligible at the angled measurement. For thicker cross section, shear stress becomes influential if the depth of penetration of Rayleigh wave is greater than the half of the thickness. The influences of plate thickness and ultrasonic frequency on the identification of stress tensor are numerically studied in 3D structural geometry and Murnaghan material model. The experimental component of this study includes uniaxial loading of the plate while measuring ultrasonic wave at three directions (perpendicular, parallel and angled to the loading direction). Instead of rotating transmitter-receiver pair for each test, a device capable of measuring the three angles is designed.

  9. Comparing measured with simulated vertical soil stress under vehicle load

    Keller, Thomas; Lamandé, Mathieu; Arvidsson, Johan;

    in the soil profile at 0.3, 0.5 and 0.7 m depth was measured during wheeling at field capacity on five soils (13-66% clay). Stress propagation was then simulated with the semi-analytical model, using vertical stress at 0.1 m depth estimated from tyre characteristics as upper boundary condition, and v...

  10. Comparing measured with simulated vertical soil stress under vehicle load

    Keller, Thomas; Lamandé, Mathieu; Arvidsson, Johan

    in the soil profile at 0.3, 0.5 and 0.7 m depth was measured during wheeling at field capacity on five soils (13-66% clay). Stress propagation was then simulated with the semi-analytical model, using vertical stress at 0.1 m depth estimated from tyre characteristics as upper boundary condition, and v...

  11. Transient water stress in a vegetation canopy - Simulations and measurements

    Carlson, Toby N.; Belles, James E.; Gillies, Robert R.


    Consideration is given to observational and modeling evidence of transient water stress, the effects of the transpiration plateau on the canopy radiometric temperature, and the factors responsible for the onset of the transpiration plateau, such as soil moisture. Attention is also given to the point at which the transient stress can be detected by remote measurement of surface temperature.

  12. Measurement of spatial stress gradients near grain boundaries

    Basu, Indranil; Ocelík, Vaclav; De Hosson, Jeff Th M.


    A correlative method based on electron back scattered diffraction and focused ion-beam–digital image correlation slit milling technique was used to quantitatively determine spatially resolved stress profiles in the vicinity of grain boundaries in pure titanium. Measured local stress gradients were

  13. 3D Tyre/Road pavement contact stress measurements

    De Beer, Morris


    Full Text Available The CSIR’s proprietary Stress-in-Motion (SIM) measurements provide rational descriptions of 1D, 2D and 3D tyre/road pavement stresses for: Road pavement design testing and evaluation, as well as tyre design, testing and evaluation....

  14. Stress effects in prism coupling measurements of thin polymer films

    Agan, S.; Ay, F.; Kocabas, A.; Aydinli, A.


    Due to the increasingly important role of some polymers in optical waveguide technologies, precise measurement of their optical properties has become important. Typically, prism coupling to slab waveguides made of materials of interest is used to measure the relevant optical parameters. However, such measurements are often complicated by the softness of the polymer films when stress is applied to the prism to couple light into the waveguides. In this work, we have investigated the optical properties of three different polymers, polystyrene (PS), polymethyl-methacrylate (PMMA), and benzocyclobutane (BCB). For the first time, the dependence of the refractive index, film thickness, and birefringence on applied stress in these thin polymer films was determined by means of the prism coupling technique. Both symmetric trapezoid shaped and right-angle prisms were used to couple the light into the waveguides. It was found that trapezoid shaped prism coupling gives better results in these thin polymer films. The refractive index of PMMA was found to be in the range of 1.4869 up to 1.4876 for both TE and TM polarizations under the applied force, which causes a small decrease in the film thickness of up to 0.06 μm. PMMA waveguide films were found not to be birefringent. In contrast, both BCB and PS films exhibit birefringence albeit of opposing signs.

  15. A Comparison between Deep and Shallow Stress Fields in Korea Using Earthquake Focal Mechanism Inversions and Hydraulic Fracturing Stress Measurements

    Lee, Rayeon; Chang, Chandong; Hong, Tae-kyung; Lee, Junhyung; Bae, Seong-Ho; Park, Eui-Seob; Park, Chan


    We are characterizing stress fields in Korea using two types of stress data: earthquake focal mechanism inversions (FMF) and hydraulic fracturing stress measurements (HF). The earthquake focal mechanism inversion data represent stress conditions at 2-20 km depths, whereas the hydraulic fracturing stress measurements, mostly conducted for geotechnical purposes, have been carried out at depths shallower than 1 km. We classified individual stress data based on the World Stress Map quality ranking scheme. A total of 20 FMF data were classified into A-B quality, possibly representing tectonic stress fields. A total of 83 HF data out of compiled 226 data were classified into B-C quality, which we use for shallow stress field characterization. The tectonic stress, revealed from the FMF data, is characterized by a remarkable consistency in its maximum stress (σ1) directions in and around Korea (N79±2° E), indicating a quite uniform deep stress field throughout. On the other hand, the shallow stress field, represented by HF data, exhibits local variations in σ1 directions, possibly due to effects of topography and geologic structures such as faults. Nonetheless, there is a general similarity in σ1 directions between deep and shallow stress fields. To investigate the shallow stress field statistically, we follow 'the mean orientation and wavelength analysis' suggested by Reiter et al. (2014). After the stress pattern analysis, the resulting stress points distribute sporadically over the country, not covering the entire region evenly. In the western part of Korea, the shallow σ1directions are generally uniform with their search radius reaching 100 km, where the average stress direction agrees well with those of the deep tectonic stress. We note two noticeable differences between shallow and deep stresses in the eastern part of Korea. First, the shallow σ1 orientations are markedly non-uniform in the southeastern part of Korea with their search radius less than 25 km

  16. Measuring Stress and Ability to Recover from Stress with Salivary Alpha-Amylase Levels


    to be resilient. So what is salivary alpha amylase ? To start, an amylase is enzyme in the body that hydrolyzes starch (breaks it down) into...Ability to Recover from Stress with Salivary α- Amylase Levels Authors Brandon L. Mulrine Michael F. Sheehan Lolita M. Burrell Michael...TITLE AND SUBTITLE Measuring Stress and Ability to Recover from Stress with Salivary Alpha Amylase Levels 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  17. Stress-strain characteristics of materials at high strain rates. Part II. Experimental results

    Ripperger, E. A. [Texas. Univ., Austin, TX (US). Structural Mechanics Research Lab.


    These two reports were issued separately, but are cataloged as a unit. A photoelectric method for measuring displacements during high-velocity impacts is described. The theory of the system is discussed in detail, and a prototype system which was built and tested is described. The performance of the prototype system is evaluated by comparing the results which it gives with results obtained by other methods of measurement. The system was found capable of a resolution of at least 0.01 inches. static and dynamic stress-strain characteristics of seven high polymers, polyethylene, teflon, nylon, tenite M, tenite H, polystyrene, and saran, plus three metals, lead, copper, and aluminum, are described and compared by means of stress-strain curves and photographs. Data are also presented which show qualitatively the effects produced on stress-strain characteristics by specimen configuration, temperature, and impact velocity. It is shown that there is a definite strain-rate effect for all these materials except polystyrene. The effect is one of an apparent stiffening of the material with increasing strain rate, which is similar to the effect produced by lowering the temperature. The stress-strain measurements are examined critically, inconsistencies are pointed out, and possible sources of error suggested. Values of yield stress, modulus of elasticity and energy absorption for all materials (except copper and aluminum), specimen configurations, temperatures, and impact velocities included in the investigation are tabulated.

  18. Combined risk measures: representation results and applications

    Göttsche, Ove Ernst


    The analysis and interpretation of risk play a crucial role in different areas of modern finance. This includes pricing of financial products, capital allocation and derivation of economic capital. Key to this analysis is the quantification of the risk via risk measures. A promising approach is to d

  19. High precision stress measurements in semiconductor structures by Raman microscopy

    Uhlig, Benjamin


    Stress in silicon structures plays an essential role in modern semiconductor technology. This stress has to be measured and due to the ongoing miniaturization in today's semiconductor industry, the measuring method has to meet certain requirements. The present thesis deals with the question how Raman spectroscopy can be used to measure the state of stress in semiconductor structures. In the first chapter the relation between Raman peakshift and stress in the material is explained. It is shown that detailed stress maps with a spatial resolution close to the diffraction limit can be obtained in structured semiconductor samples. Furthermore a novel procedure, the so called Stokes-AntiStokes-Difference method is introduced. With this method, topography, tool or drift effects can be distinguished from stress related influences in the sample. In the next chapter Tip-enhanced Raman Scattering (TERS) and its application for an improvement in lateral resolution is discussed. For this, a study is presented, which shows the influence of metal particles on the intensity and localization of the Raman signal. A method to attach metal particles to scannable tips is successfully applied. First TERS scans are shown and their impact on and challenges for high resolution stress measurements on semiconductor structures is explained. (orig.)

  20. Ultrasonic measurement of residual stress in shot peened aluminum alloy

    Lavrentyev, Anton I.; Veronesi, William A.


    Shot peening is a well-known method for extending the fatigue life of metal components by introducing compressive residual stresses near their surfaces. The capability to non-destructively evaluate the near surface residual stress would greatly aid the assurance of proper fatigue life in shot-peened components. This paper addresses issues encountered in near-surface residual stress measurement by an ultrasonic surface wave method. In this method, a variation of ultrasonic surface wave speed with shot peening intensity is measured. Since the effective wave penetration depth inversely related to the excitation frequency, by making measurements at different frequencies, the method has the potential to provide the stress-depth profile. Experiments were conducted on aluminum specimens (alloy 7075-T7351) peened within the Almen peening intensity from 4A-16A. Several factors were found to contribute to the measured responses: surface roughness, near surface texture change, dislocation density increase and residual stress. In this paper, the contributions of residual stress, dislocation density and surface roughness to the overall effect are separately estimated. It is shown that the experimentally observed velocity change in shot peened samples is dominated by the effect of surface roughness while the role of residual stress is much smaller.



    In this article, a shear plate was mounted on the bottom in a wave flume and direct measurements of the smooth and rough bed shear stress under regular and irregular waves were conducted with the horizontal force exerted on the shear plates by the bottom shear stress in the wave boundary layer. Under immobile bed condition, grains of sand were glued uniformly and tightly onto the shear plate, being prevented from motion with the fluid flow and generation of sand ripples. The distribution of the bottom mean shear stress varying with time was measured by examining the interaction between the shear plate and shear transducers. The relation between the force measured by the shear transducers and its voltage is a linear one. Simultaneous measurements of the bottom velocity were carried out by an Acoustic Doppler Velocimeter (ADV), while the whole process was completely controlled by computers, bottom shear stress and velocity were synchronously measured. Based on the experimental results, it can be concluded that (1) the friction coefficient groews considerably with the increase of the Reynolds number, (2) the shear stress is a function varying with time and linearly proportional to the velocity. Compared with theoretical results and previous experimental data, it is shown that the experimental method is feasible and effective, A further study on the bed shear stress under regular or irregular waves can be carried out. And applicability to the laboratory studies on the initiation of sediments and the measurement of the shear stress after sediment imigration.



    Traditional methods of residual stress measurement are generally destructive or semi-destructive, as well as expensive, time-consuming and complex to implement. With the new development of welded structure, traditional methods can not satisfy the need of full life task management. So the acoustical theory is introduced, since the ultrasonic technique provides a useful nondestructive tool in the evaluation of stresses. In this study an ultrasonic stress measurement experimental installation is established, which consists of a special transducer, a signal emission unit and a signal recipient processing unit. Longitudinal critically refracted wave is selected as the measurement wave mode. The supporting software is programmed by Labview software. The longitudinal residual stress and transverse residual stress of twin wire welded plate are measured by this installment, in which the measuring process is real-time, quick and nondestructive. The experiment results indicate that the system can satisfy the need of life evaluation for welded structure. The system is light and portable.

  3. Remarks on residual stress measurement by hole-drilling and electronic speckle pattern interferometry.

    Barile, Claudia; Casavola, Caterina; Pappalettera, Giovanni; Pappalettere, Carmine


    Hole drilling is the most widespread method for measuring residual stress. It is based on the principle that drilling a hole in the material causes a local stress relaxation; the initial residual stress can be calculated by measuring strain in correspondence with each drill depth. Recently optical techniques were introduced to measure strain; in this case, the accuracy of the final results depends, among other factors, on the proper choice of the area of analysis. Deformations are in fact analyzed within an annulus determined by two parameters: the internal and the external radius. In this paper, the influence of the choice of the area of analysis was analysed. A known stress field was introduced on a Ti grade 5 sample and then the stress was measured in correspondence with different values of the internal and the external radius of analysis; results were finally compared with the expected theoretical value.

  4. Measurement of lattice rotations and internal stresses in over one hundred individual grains during a stress-induced martensitic transformation

    Hachi Younes El


    Full Text Available To better understand the properties of polycrystals at a microscopic scale during cyclic mechanical loading we have measured the relationship between grain orientations, their positions inside the sample and their internal stresses. In this work, in-situ 3DXRD technique was performed on over hundred grains during the stress-induced martensitic transformation in a Cu-Al-Be shape memory alloy. Information about the position, orientation, and stress field was obtained for each austenitic grain. These results have been used to develop a procedure that allows automatic processing for a large number of grains, matching them during loading and leads to a quantitative stress field. A strong heterogeneity of stress state between the grains at the surface and in the volume is evident.

  5. Three dimensional measurement of rhinoplasty results.

    Heerbeek, N. van; Ingels, K.J.A.O.; Loon, B. van; Plooij, J.M.; Berge, S.J.


    BACKGROUND: Pre- and postoperative imaging is important and essential for evaluation of the results of rhinoplasty surgery. Two-dimensional photographs are used routinely for this purpose, but have several disadvantages as opposed to three-dimensional imaging techniques, such as

  6. Repeated swim stress alters brain benzodiazepine receptors measured in vivo

    Weizman, R.; Weizman, A.; Kook, K.A.; Vocci, F.; Deutsch, S.I.; Paul, S.M.


    The effects of repeated swim stress on brain benzodiazepine receptors were examined in the mouse using both an in vivo and in vitro binding method. Specific in vivo binding of (/sup 3/H)Ro15-1788 to benzodiazepine receptors was decreased in the hippocampus, cerebral cortex, hypothalamus, midbrain and striatum after repeated swim stress (7 consecutive days of daily swim stress) when compared to nonstressed mice. In vivo benzodiazepine receptor binding was unaltered after repeated swim stress in the cerebellum and pons medulla. The stress-induced reduction in in vivo benzodiazepine receptor binding did not appear to be due to altered cerebral blood flow or to an alteration in benzodiazepine metabolism or biodistribution because there was no difference in (14C)iodoantipyrine distribution or whole brain concentrations of clonazepam after repeated swim stress. Saturation binding experiments revealed a change in both apparent maximal binding capacity and affinity after repeated swim stress. Moreover, a reduction in clonazepam's anticonvulsant potency was also observed after repeated swim stress (an increase in the ED50 dose for protection against pentylenetetrazol-induced seizures), although there was no difference in pentylenetetrazol-induced seizure threshold between the two groups. In contrast to the results obtained in vivo, no change in benzodiazepine receptor binding kinetics was observed using the in vitro binding method. These data suggest that environmental stress can alter the binding parameters of the benzodiazepine receptor and that the in vivo and in vitro binding methods can yield substantially different results.

  7. Demonstration of over core stress measurement from surface using the Sigra IST tool

    Gray, I


    Full Text Available 7 Core Sample Mechanical Properties Page 8 Stress Measurement Results Page 8 Principal and Tectonic Stresses and Tectonic Strains Page 9 Conclusions Page 11 Acknowledgments Page 11 Table 1 Sample Descriptions... Solutions Page 26 Appendix D Directional Survey Information Page 39 Appendix E Photographs of Each Test Core Page 41 4 5 TABLES Table 1- Sample Descriptions and Material...

  8. Measuring residual stress in ceramic zirconia-porcelain dental crowns by nanoindentation.

    Zhang, Y; Allahkarami, M; Hanan, J C


    Residual stress plays a critical role in failure of ceramic dental crowns. The magnitude and distribution of residual stress in the crown system are largely unknown. Determining the residual stress quantitatively is challenging since the crown has such complex contours and shapes. This work explored the feasibility and validity of measuring residual stress of zirconia and porcelain in ceramic crowns by nanoindentation. Nanoindentation tests were performed on the cross-section of a crown for both porcelain and zirconia along four critical locations: the thickest, thinnest and medium porcelain thicknesses. Zirconia and porcelain pieces, chipped off from the crown and annealed at 400 °C, were used as reference samples. The residual stress was determined by comparing the measured hardness of the stressed sample with that of the reference sample. Nanoindentation impression images were acquired through a scanning probe microscope (SPM) equipped with a Hysitron Triboindenter. Zirconia showed large pile-up. Residual stress is determined along the thickness of crowns at the chosen locations for both porcelain and zirconia. The measured results were compared with the results from X-ray diffraction (XRD) and finite element modeling (FEM). Results show there are large amounts of residual stresses in the dental crown and their magnitude differs between locations due to the complex shape of the crown. The average residual stress readings were as high as -637 MPa and 323 MPa for zirconia and porcelain respectively.

  9. Buried wire gage for wall shear stress measurements

    Murthy, V. S.; Rose, W. C.


    A buried wire gage for measuring wall shear stress in fluid flow was studied and further developed. Several methods of making this relatively new type of gage were examined to arrive at a successful technique that is well-suited for wind-tunnel testing. A series of measurements was made to demonstrate the adequacy of a two-point calibration procedure for these gages. The buried wire gage is also demonstrated to be ideally suited for quantitative measurement of wall shear stress in wind-tunnel testing.

  10. Measuring occupational stress: development of the pressure management indicator.

    Williams, S; Cooper, C L


    The study of occupational stress is hindered by the lack of compact and comprehensive standardized measurement tools. The Pressure Management Indicator (PMI) is a 120-item self-report questionnaire developed from the Occupational Stress Indicator (OSI). The PMI is more reliable, more comprehensive, and shorter than the OSI. It provides an integrated measure of the major dimensions of occupational stress. The outcome scales measure job satisfaction, organizational satisfaction, organizational security, organizational commitment, anxiety--depression, resilience, worry, physical symptoms, and exhaustion. The stressor scales cover pressure from workload, relationships, career development, managerial responsibility, personal responsibility, home demands, and daily hassles. The moderator variables measure drive, impatience, control, decision latitude, and the coping strategies of problem focus, life work balance, and social support.

  11. Residual stress measurement in silicon sheet by shadow moire interferometry

    Kwon, Y.; Danyluk, S.; Bucciarelli, L.; Kalejs, J. P.


    A shadow moire interferometry technique has been developed to measure residual strain in thin silicon sheet. The curvature of a segment of sheet undergoing four-point bending is analyzed to include the applied bending moments, the in-plane residual stresses, and the 'end effect' of the sheet since it is of finite length. The technique is applied to obtain residual stress distributions for silicon sheet grown by the edge-defined film-fed growth technique.

  12. Measuring Propellant Stress Relaxation Modulus Using Dynamic Mechanical Analyzer


    P. N., Singh, P. P., and Bhattacharya, B., “Determination of Activation Energy of Relaxation Events in Composite Solid Propellants by Dynamic...Article 3. DATES COVERED (From - To) 04 August 2016 – 29 March 2017 4. TITLE AND SUBTITLE Measuring Propellant Stress Relaxation Modulus Using Dynamic...ERC 14. ABSTRACT A method for determining the stress relaxation master curve of solid rocket propellants was developed. The propellant was tested in

  13. Research on Measurement of Bed Shear Stress Under WaveCurrent Interaction

    徐华; 夏云峰; 张世钊马炳和; 郝思禹; 杜德军


    The movement of sediment in estuary and on coast is directly restricted by the bed shear stress. Therefore, the research on the basic problem of sediment movement by the bed shear stress is an important way to research the theory of sediment movement. However, there is not a measuring and computing method to measure the bed shear stress under a complicated dynamic effect like wave and current. This paper describes the measurement and test research on the bed shear stress in a long launder of direct current by the new instrument named thermal shearometer based on micro-nanotechnology. As shown by the research results, the thermal shearometer has a high response frequency and strong stability. The measured results can reflect the basic change of the bed shear stress under wave and wave-current effect, and confirm that the method of measuring bed shear stress under wave-current effect with thermal shearometer is feasible. Meanwhile, a preliminary method to compute the shear stress compounded by wave-current is put forward according to the tested and measured results, and then a reference for further study on the basic theory of sediment movement under a complicated dynamic effect is provided.

  14. Post Traumatic Stress Disorder (PTSD): NIH Research to Results

    ... virtual reality" (VR) exposure therapy. The VR therapy combines traditional therapy and exposure via VR technology that ... families. Read More "Post Traumatic Stress Disorder (PTSD)" Articles PTSD: A Growing Epidemic / Symptoms, Diagnosis, Treatment / NIH ...

  15. Spallation and fracture resulting from reflected and intersecting stress waves.

    Kinslow, R.


    Discussion of the effects of stress waves produced in solid by explosions or high-velocity impacts. These waves rebound from free surfaces in the form of tensile waves that are capable of causing internal fractures or spallation of the material. The high-speed framing camera is shown to be an important tool for observing the stress waves and fracture in transparent targets, and its photographs provide valuable information on the mechanics of fracture.

  16. Measurement invariance of the perceived stress scale and latent mean differences across gender and time.

    Barbosa-Leiker, Celestina; Kostick, Marylynne; Lei, Ming; McPherson, Sterling; Roper, Virginia; Hoekstra, Trynke; Wright, Bruce


    Measurement invariance of the 2-factor model of the Perceived Stress Scale--10-item version (Cohen & Williamson, 1988) was tested across men and women at two time points and in the combined total sample over a 2-year time frame (n = 871). Measurement invariance results indicated that the scale measured the latent factors, stress and counter-stress, equivalently in men and women and over time. With measurement invariance demonstrated, differences in latent means were tested. Results indicated that men had lower levels of frequencies of stressors, and at one time point, higher levels of counter-stress, when compared with women. When examining change in frequencies of stressors and counter-stress over 2 years with the combined male and female sample, stressors remained stable, yet counter-stress increased over time. These findings may aid in the interpretation of results when examining stressors and counter-stress in clinical samples where one would expect stress to increase, whereas positive psychological states decrease.

  17. Eo-1 Hyperion Measures Canopy Drought Stress In Amazonia

    Asner, Gregory P.; Nepstad, Daniel; Cardinot, Gina; Moutinho, Paulo; Harris, Thomas; Ray, David


    The central, south and southeast portions of the Amazon Basin experience a period of decreased cloud cover and precipitation from June through November. There are likely important effects of seasonal and interannual rainfall variation on forest leaf area index, canopy water stress, productivity and regional carbon cycling in the Amazon. While both ground and spaceborne studies of precipitation continue to improve, there has been almost no progress made in observing forest canopy responses to rainfall variability in the humid tropics. This shortfall stems from the large stature of the vegetation and great spatial extent of tropical forests, both of which strongly impede field studies of forest responses to water availability. Those few studies employing satellite measures of canopy responses to seasonal and interannual drought (e.g., Bohlman et al. 1998, Asner et al. 2000) have been limited by the spectral resolution and sampling available from Landsat and AVHRR sensors. We report on a study combining the first landscape-level, managed drought experiment in Amazon tropical forest with the first spaceborne imaging spectrometer observations of this experimental area. Using extensive field data on rainfall inputs, soil water content, and both leaf and canopy responses, we test the hypothesis that spectroscopic signatures unique to hyperspectral observations can be used to quantify relative differences in canopy stress resulting from water availability.

  18. Molecular force sensors to measure stress in cells

    Prabhune, Meenakshi; Rehfeldt, Florian; Schmidt, Christoph F.


    Molecularly generated forces are essential for most activities of biological cells, but also for the maintenance of steady state or homeostasis. To quantitatively understand cellular dynamics in migration, division, or mechanically guided differentiation, it will be important to exactly measure stress fields within the cell and the extracellular matrix. Traction force microscopy and related techniques have been established to determine the stress transmitted from adherent cells to their substrates. However, different approaches are needed to directly assess the stress generated inside the cell. This has recently led to the development of novel molecular force sensors. In this topical review, we briefly mention methods used to measure cell-external forces, and then summarize and explain different designs for the measurement of cell-internal forces with their respective advantages and disadvantages.

  19. Realignment of Nanocrystal Aggregates into Single Crystals as a Result of Inherent Surface Stress

    Liu, Zhaoming [Department of Chemistry, Zhejiang University, Hangzhou Zhejiang 310027 China; Pan, Haihua [Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou Zhejiang 310027 China; Zhu, Genxing [Department of Chemistry, Zhejiang University, Hangzhou Zhejiang 310027 China; Li, Yaling [Department of Chemistry, Zhejiang University, Hangzhou Zhejiang 310027 China; Tao, Jinhui [Physical Sciences Division, Pacific Northwest National Laboratory, Richland WA 99354 USA; Jin, Biao [Department of Chemistry, Zhejiang University, Hangzhou Zhejiang 310027 China; Tang, Ruikang [Department of Chemistry, Zhejiang University, Hangzhou Zhejiang 310027 China; Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou Zhejiang 310027 China


    Assembly of nanoparticles building blocks during single crystal growth is widely observed in both natural and synthetic environments. Although this form of non-classical crystallization is generally described by oriented attachment, random aggregation of building blocks leading to single crystal products is also observed, but the mechanism of crystallographic realignment is unknown. We herein reveal that random attachment during aggregation-based growth initially produces a non-oriented growth front. Subsequent evolution of the orientation is driven by the inherent surface stress applied by the disordered surface layer and results in single crystal formation via grain boundary migration. This mechanism is corroborated by measurements of orientation rate vs external stress, demonstrating a predictive relationship between the two. These findings advance our understanding of aggregation-based growth of natural minerals by nanocrystals, and suggest an approach to material synthesis that takes advantage of stress induced co-alignment.

  20. Measuring Spatial Infiltration in Stormwater Control Measures: Results and Implications

    This presentation will provide background information on research conducted by EPA-ORD on the use of soil moisture sensors in bioretention/bioinfiltration technologies to evaluate infiltration mechanisms and compares monitoring results to simplified modeling assumptions. A serie...

  1. Normal stress measurement via image analysis of interfacial deformation

    Lowry, Brian; Höpfl, Wolfgang


    The first coefficient of normal stress in polymer solutions is determined via image analysis. The method measures pointwise normal stresses along a sheared liquid-liquid interface. In the case of a steady rotating liquid bridge, the deformation of the interface is strictly due to normal stress swelling effects. In our experiments, a cylindrical liquid bridge of polystyrene solution rotates in a cylindrical bath filled with a glycerol-water solution of similar density. The shape of the interface and the jump in normal stress across the interface are determined using pressure-stress image analysis (P-SIA) from high resolution digital images. The stress resolution is better than 0.1 Pa at the free interface. The polystyrene solution exhibits a normal stress at the interface which grows with the square of the rotation rate. This effect is absent for Newtonian liquids, and is in excellent agreement with the ideal low shear behaviour of polymer solutions. Small density differences between the liquids are taken into consideration, showing that centrifugal effects are negligible. This method is potentially an excellent alternative to classical rheometry at low shear rates.

  2. Detection of stress concentrations around a defect by magnetic Barkhausen noise measurements

    Mandal, K.; Dufour, D.; Sabet-Sharghi, R.; Sijgers, B.; Micke, D.; Krause, T.W.; Clapham, L.; Atherton, D.L. [Applied Magnetics Group, Department of Physics, Queen`s University, Kingston, K7L 3N6, Ontario (Canada)


    The stress distribution around a 50{percent} blind-hole pit in a steel pipe with a 9 mm wall has been studied using high-resolution magnetic Barkhausen noise (MBN) measurements. A magnetic disk read-head is used as the pick up coil in the MBN probe. The study shows a stress concentration factor of {approximately}2 at the defect edge perpendicular to the direction of applied stress and {approximately}{minus}0.6 at the edge parallel to the same. The experimental results are consistent with the analytical solutions obtained by the Airy{close_quote}s stress function approach. {copyright} {ital 1996 American Institute of Physics.}

  3. Effect of reference point selection on microscopic stress measurement using EBSD

    Mikami, Yoshiki, E-mail: [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Oda, Kazuo [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Kamaya, Masayuki [Institute of Nuclear Safety System, Inc., 64 Sata, Mihama-cho, Mikata-gun, Fukui 919-1205 (Japan); Mochizuki, Masahito [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)


    It is important to evaluate microscopic stress distributions on the order of the grain size to clarify the deformation and fracture behavior of structural materials. In this study, the microscopic stress distribution of coarse-grained austenitic stainless steel during tensile testing was measured using a method that employs cross-correlation of the electron backscatter diffraction (EBSD) pattern, and the effect of the reference point selection on the measured stress was investigated. First, parameters that characterize the quality of the EBSD pattern measurement—namely, the image quality (IQ), confidence index (CI), and Fit—and the parameter that corresponds to the extent of the plastic deformation—the kernel average misorientation (KAM)—were used to determine the reference point. It was confirmed that the value of the microscopic stress measured using the EBSD-based approach is relative to the value of the stress state of the reference point. Second, multiple reference points were determined within a grain by considering only the location, and the stress distribution in the grain was evaluated using each of the reference points. The deviation of the measured stress was calculated from the averaged value for all the measured results using a certain reference point, and its relationship to parameters such as the IQ, CI, Fit, and KAM of the reference point used was investigated. It was demonstrated that the choice of parameters did not significantly affect the evaluation of the relative stress distribution within a grain. The results of this study therefore show that the selection of the reference point does not affect the measured stress distribution, as long as the evaluation is limited to the relative stress within a grain for the selected reference point.

  4. Neutron diffraction facility for internal stress measurements at JAERI

    Tsuchiya, Yoshinori; Minakawa, Nobuaki; Morii, Yukio [Japan Atomic Energy Research Inst., Tokyo (Japan)


    The Neutron Diffractometer for Residual Stress Analysis (RESA) is a two axis type neutron diffractometer with a goniometer controllable to specimen position in high precision for spatial distribution measurement of residual stress and with one- and zero-dimensional detectors, and has a characteristics of providing a pin-hole type neutron ray diaphragm to obtain local informations of the specimen. It is elucidated from the reported examples that the RESA in JAERI has a capacity of sufficient detection to a local strain with 10{sup -3} to 10{sup -4}. The residual stress measurement in JAERI is just in beginning state, and has many necessities to do a lot of trial measurements on various materials in future. And, when finishing the construction of pulsed neutron source under planning in JAERI, it can be expected to realize a neutron intensity of more than one hundred for the residual stress measurement and to construct a powerful measurement instrument in combination with introduction of testing method for TOF. (G.K.)

  5. Study to evaluate the effectiveness of stress management workshops on response to general and occupational measures of stress.

    Heron, R J; McKeown, S; Tomenson, J A; Teasdale, E L


    This study was designed to evaluate the effectiveness of stress management training workshops within Zeneca Pharmaceuticals. The study was of cross-sectional design, comparing groups of workshop attendees and non-attendees. In addition, self-rated well-being scores of attendees were compared with results obtained pre-workshop and 2-3 months after the workshop. Employees participating in the study were drawn from the Manufacturing, Research and Development, Sales and Marketing sites of Zeneca Pharmaceuticals located in Cheshire, United Kingdom. Three hundred and ninety persons who had participated in stress management workshops since 1988 were matched for age, gender and department with an equal number of employees who had not attended stress management workshops. Outcome measures included self-rated well-being (as measured by the 30-question General Health Questionnaire), knowledge of company guidance on the management of stress in staff, and an assessment of coping strategies. Subjects who had not attended a stress management workshop were much more likely to have a poor understanding of the principles of management of stress in staff [odds ratio (OR) = 8.3; 95% confidence interval (CI) = 3.3-21.3] and more likely to have poor coping skills (OR = 2.8; CI = 1.3-6.1). However, mean scores for the two measures were similar in attendees and non-attendees. Self-rating of current well-being was strongly associated with the life-events score, but not related to workshop attendance. The study indicates that stress management training workshops reduce the prevalence of employees with a poor understanding of the principles of the management of stress in staff and with poor coping strategies. An improvement in the self-rated well-being observed shortly after the workshop was not sustained.

  6. Measurement techniques for in situ stresses around underground constructions in a deep clay formation

    Li X.L.


    Full Text Available Disposal in deep underground geological formations is internationally recognized as the most viable option for the long-term management of high-level radioactive waste. In Belgium, the Boom clay formation is extensively studied in this context, in particular at the 225 m deep HADES Underground Research Facility in Mol. A cost-effective design of deep underground structures requires an accurate assessment of the in situ stresses; a good estimation of these stresses is also essential when interpreting in situ experiments regarding the hydro-mechanical behaviour of the host formation. Different measurement techniques are available to provide data on the stress evolution and other mechanical properties of the geological formation. The measurement can be direct (measurement of total pressure, or it can be an indirect technique, deriving the stress from related quantities such as strain (changes in structural members. Most total stress measurements are performed through permanently installed sensors; also once-only measurements are performed through specific methods (e.g. pressuremeter. Direct measurement of the stress state is challenging due to the complex mechanical behaviour of the clay, and the fact that the sensor installation inevitably disturbs the original stress field. This paper describes ways to deal with these problems and presents the results obtained using different techniques at HADES.

  7. A New Method to Identify Quaternary Moraine:Acoustic Emission Stress Measurement

    ZHAO Zhizhong; QIAO Yansong; TIAN Jiaorong; WANG Min; LI Mingze; HE Peiyuan; QIAN Fang


    How to effectively identify glacial sediments, especially Quaternary moraine, has been in dispute for decades. The traditional methods, e.g., sedimentary and geomorphologic ones, are facing challenge in eastern China where controversial moraine deposits are dominatingly distributed. Here,for the first time, we introduce the acoustic emission (AE) stress measurement, a kind of historical stress measurement, to identify Quaternary moraine. The results demonstrate that it can be employed to reconstruct stress information of glaciation remaining in gravels, and may shed light on the identification of Quaternary moraine in eastern China. First, we measured the AE stress of gravels of glacial origin that are underlying the Xidatan Glacier, eastern Kunlun Mountains in western China.Second, we calculated the stress according to the actual thickness of the glacier. The almost identical stress values suggest that the glacial gravels can memorize and preserve the overlying glacier-derived aplomb stress. And then we introduce this new approach to the controversial moraine in Mount Lushan, eastern China. The results indicate that the stress is attributed to the Quaternary glacier, and the muddy gravels in the controversial moraine in Mount Lushan are moraine deposits but not others.

  8. The Acute Effect of Aerobic Exercise on Measures of Stress.

    Fort, Inza L.; And Others

    The immediate response of stress to aerobic exercise was measured by utilizing the Palmar Sweat Index (PSI) and the State-Trait Anxiety Inventory (STAI). Forty subjects (20 male and 20 female) from the ages of 18-30 sustained a single bout of aerobic activity for 30 minutes at 60 percent of their maximum heart rate. Pre-treatment procedures…

  9. Measuring short-term stress in birds: Comparing different endpoints of the endocrine-immune interface.

    Huber, Nikolaus; Fusani, Leonida; Ferretti, Andrea; Mahr, Katharina; Canoine, Virginie


    Stress is a collective term for certain conditions and sequences of physiological events enabling living organisms to overcome unpredictable and uncontrollable situations. The context-dependent nature, multidimensional course and large individual variability make stress responses difficult to measure. In avian species, a plethora of studies on short-term stress responses have been conducted by measuring the corticosteroid response to a standardized stress protocol. Here we aimed to test the viability of the Leukocyte Coping Capacity (LCC), measuring oxygen radical production by leukocytes, to assess short-term stress in birds. We collected blood samples from captive house sparrows (Passer domesticus) in the two seasons of winter and spring, right after capture and 30min thereafter. In order to assess the overall physiological stress response to a standardized stressor, i.e. handling and temporary constraint, we measured LCC and additionally combined it with measures of total circulating glucocorticoids (GCs) and oxidative stress. All three methodologies detected significant changes due to the stressor albeit they were not correlated with each other and revealed different information. There was no significant change in oxidative stress levels between the two time points although the amount of relative oxidative damage as well as the anti-oxidative capacity changed significantly. We observed a significant seasonal difference in GC stress response with no difference between sexes. On the contrary, LCC measures revealed with a high individual consistency, that individuals experienced a similar magnitude of stress in both seasons with a significant difference between sexes. Total GC-levels have to be interpreted with caution regarding the assessment of short-term stress reactions. We therefore suggest to supplementary combine classical approaches for measuring stress with the immunological tool of LCC. Our results reveal LCC as a strong and reliable tool to assess short

  10. Stunning fish with CO2 or electricity: contradictory results on behavioural and physiological stress responses.

    Gräns, A; Niklasson, L; Sandblom, E; Sundell, K; Algers, B; Berg, C; Lundh, T; Axelsson, M; Sundh, H; Kiessling, A


    Studies that address fish welfare before slaughter have concluded that many of the traditional systems used to stun fish including CO2 narcosis are unacceptable as they cause avoidable stress before death. One system recommended as a better alternative is electrical stunning, however, the welfare aspects of this method are not yet fully understood. To assess welfare in aquaculture both behavioural and physiological measurements have been used, but few studies have examined the relationship between these variables. In an on-site study aversive behaviours and several physiological stress indicators, including plasma levels of cortisol and ions as well as blood physiological variables, were compared in Arctic char (Salvelinus alpinus) stunned with CO2 or electricity. Exposure to water saturated with CO2 triggered aversive struggling and escape responses for several minutes before immobilization, whereas in fish exposed to an electric current immobilization was close to instant. On average, it took 5 min for the fish to recover from electrical stunning, whereas fish stunned with CO2 did not recover. Despite this, the electrically stunned fish had more than double the plasma levels of cortisol compared with fish stunned with CO2. This result is surprising considering that the behavioural reactions were much more pronounced following CO2 exposure. These contradictory results are discussed with regard to animal welfare and stress physiological responses. The present results emphasise the importance of using an integrative and interdisciplinary approach and to include both behavioural and physiological stress indicators in order to make accurate welfare assessments of fish in aquaculture.

  11. Research on a system and method of automated whole-field measurement of optical glass stress

    Zhang, Li-jun; Tang, Yi; Bai, Ting-zhu


    On the basis of the principle of single quarter wave plate method, a model of automatic whole-field measuring optical glass stress is presented, which is called "4+1steps phase shifting method" including the model for the isoclinic parameter and the stress birefringence. According to this model, an automatic whole-field measuring system is established. The correctness of the model was testified by numeric emulation experiments under the preset conditions of isoclinic angle and stress birefringence. Practical measurement obtained a result coincident with the actual distribution of the isoclinic angle and the birefringence. The automatic whole-field measuring model and system can achieve the whole process intelligently and automatically, and dispose the disadvantages of tradition method about interpreting the stress level by subjective judging birefringence of some selected spots.

  12. Comparison of surface wind stress measurements - Airborne radar scatterometer versus sonic anemometer

    Brucks, J. T.; Leming, T. D.; Jones, W. L.


    Sea surface wind stress measurements recorded by a sonic anemometer are correlated with airborne scatterometer measurements of ocean roughness (cross section of radar backscatter) to establish the accuracy of remotely sensed data and assist in the definition of geophysical algorithms for the scatterometer sensor aboard Seasat A. Results of this investigation are as follows: Comparison of scatterometer and sonic anemometer wind stress measurements are good for the majority of cases; however, a tendency exists for scatterometer wind stress to be somewhat high for higher wind conditions experienced in this experiment (6-9 m/s). The scatterometer wind speed algorithm tends to overcompute the higher wind speeds by approximately 0.5 m/s. This is a direct result of the scatterometer overestimate of wind stress from which wind speeds are derived. Algorithmic derivations of wind speed and direction are, in most comparisons, within accuracies defined by Seasat A scatterometer sensor specifications.

  13. Measuring multiple residual-stress components using the contour method and multiple cuts

    Prime, Michael B [Los Alamos National Laboratory; Swenson, Hunter [Los Alamos National Laboratory; Pagliaro, Pierluigi [U. PALERMO; Zuccarello, Bernardo [U. PALERMO


    The conventional contour method determines one component of stress over the cross section of a part. The part is cut into two, the contour of the exposed surface is measured, and Bueckner's superposition principle is analytically applied to calculate stresses. In this paper, the contour method is extended to the measurement of multiple stress components by making multiple cuts with subsequent applications of superposition. The theory and limitations are described. The theory is experimentally tested on a 316L stainless steel disk with residual stresses induced by plastically indenting the central portion of the disk. The stress results are validated against independent measurements using neutron diffraction. The theory has implications beyond just multiple cuts. The contour method measurements and calculations for the first cut reveal how the residual stresses have changed throughout the part. Subsequent measurements of partially relaxed stresses by other techniques, such as laboratory x-rays, hole drilling, or neutron or synchrotron diffraction, can be superimposed back to the original state of the body.

  14. A Steel Wire Stress Measuring Sensor Based on the Static Magnetization by Permanent Magnets.

    Deng, Dongge; Wu, Xinjun; Zuo, Su


    A new stress measuring sensor is proposed to evaluate the axial stress in steel wires. Without using excitation and induction coils, the sensor mainly consists of a static magnetization unit made of permanent magnets and a magnetic field measurement unit containing Hall element arrays. Firstly, the principle is illustrated in detail. Under the excitation of the magnetization unit, a spatially varying magnetized region in the steel wire is utilized as the measurement region. Radial and axial magnetic flux densities at different lift-offs in this region are measured by the measurement unit to calculate the differential permeability curve and magnetization curve. Feature parameters extracted from the curves are used to evaluate the axial stress. Secondly, the special stress sensor for Φ5 and Φ7 steel wires is developed accordingly. At last, the performance of the sensor is tested experimentally. Experimental results show that the sensor can measure the magnetization curve accurately with the error in the range of ±6%. Furthermore, the obtained differential permeability at working points 1200 A/m and 10000 A/m change almost linearly with the stress in steel wires, the goodness of linear fits are all higher than 0.987. Thus, the proposed steel wire stress measuring sensor is feasible.

  15. A Steel Wire Stress Measuring Sensor Based on the Static Magnetization by Permanent Magnets

    Dongge Deng


    Full Text Available A new stress measuring sensor is proposed to evaluate the axial stress in steel wires. Without using excitation and induction coils, the sensor mainly consists of a static magnetization unit made of permanent magnets and a magnetic field measurement unit containing Hall element arrays. Firstly, the principle is illustrated in detail. Under the excitation of the magnetization unit, a spatially varying magnetized region in the steel wire is utilized as the measurement region. Radial and axial magnetic flux densities at different lift-offs in this region are measured by the measurement unit to calculate the differential permeability curve and magnetization curve. Feature parameters extracted from the curves are used to evaluate the axial stress. Secondly, the special stress sensor for Φ5 and Φ7 steel wires is developed accordingly. At last, the performance of the sensor is tested experimentally. Experimental results show that the sensor can measure the magnetization curve accurately with the error in the range of ±6%. Furthermore, the obtained differential permeability at working points 1200 A/m and 10000 A/m change almost linearly with the stress in steel wires, the goodness of linear fits are all higher than 0.987. Thus, the proposed steel wire stress measuring sensor is feasible.

  16. Linear and nonlinear modulus surfaces in stress space, from stress-strain measurements on Berea sandstone

    M. Boudjema


    Full Text Available The elastic response of many rocks to quasistatic stress changes is highly nonlinear and hysteretic, displaying discrete memory. Rocks also display unusual nonlinear response to dynamic stress changes. A model to describe the elastic behavior of rocks and other consolidated materials is called the Preisach-Mayergoyz (PM space model. In contrast to the traditional analytic approach to stress-strain, the PM space picture establishes a relationship between the quasistatic data and a number density of hysteretic mesoscopic elastic elements in the rock. The number density allows us to make quantitative predictions of dynamic elastic properties. Using the PM space model, we analyze a complex suite of quasistatic stress-strain data taken on Berea sandstone. We predict a dynamic bulk modulus and a dynamic shear modulus surface as a function of mean stress and shear stress. Our predictions for the dynamic moduli compare favorably to moduli derived from time of flight measurements. We derive a set of nonlinear elastic constants and a set of constants that describe the hysteretic behavior of the sandstone.

  17. Measuring mechanical stresses on inserts during injection molding

    Martina Heinle


    Full Text Available Assembly molding presents an interesting approach to innovative product solutions. Here, individual components can be simultaneously positioned, affixed, and provided with a casing. However, while overmolding elements in the mold cavity with hot polymer melt, high mechanical loads occur on, in some cases, very sensitive components such as electronic devices. For the design of such systems, it is important to know these stresses, the influences on their quantities, and mathematical options for their prediction. In this article, a new measurement method for determining the forces acting on a small element in the cavity during the injection molding process in three dimensions is presented. Therefore, a new installation method for a force sensor was developed. The results in this article concentrate on force changes during one molding cycle. Our research shows that there are different mechanical load spectra in the different phases of the molding process. For example, the force component in flow direction on an element in the cavity is positive in the direction of the flow during filling. However, after the filling step, the force becomes negative due to the contraction of the injected material and results in a continuously increasing permanent force.

  18. Raman microprobe measurements of stress in ion implanted materials

    Nugent, K.W.; Prawer, S.; Weiser, P.S.; Dooley, S.P. [Melbourne Univ., Parkville, VIC (Australia). School of Physics


    Raman microprobe measurements of ion implanted diamond and silicon have shown significant shifts in the Raman line due to stresses in the materials. The Raman line shifts to higher energy if the stress is compressive and to lower energy for tensile stress{sup 1}. The silicon sample was implanted in a 60 {mu}m square with 2.56 x 10{sup 17} ions per square centimeter of 2 MeV Helium. This led to the formation of raised squares with the top 370mm above the original surface. In Raman studies of silicon using visible light, the depth of penetration of the laser beam into the sample is much less than one micron. It was found that the Raman line is due to the silicon overlying the damage region. The diamond sample was implanted with 2 x 10{sup 15} ions per square centimeter of 2.8 MeV carbon. It was concluded that the Raman spectrum could provide information concerning both the magnitude and the direction of stress in an ion implanted sample. It was possible in some cases to determine whether the stress direction is parallel or perpendicular to the sample surface. 1 refs., 2 figs.

  19. Stress Rupture Life Reliability Measures for Composite Overwrapped Pressure Vessels

    Murthy, Pappu L. N.; Thesken, John C.; Phoenix, S. Leigh; Grimes-Ledesma, Lorie


    Composite Overwrapped Pressure Vessels (COPVs) are often used for storing pressurant gases onboard spacecraft. Kevlar (DuPont), glass, carbon and other more recent fibers have all been used as overwraps. Due to the fact that overwraps are subjected to sustained loads for an extended period during a mission, stress rupture failure is a major concern. It is therefore important to ascertain the reliability of these vessels by analysis, since the testing of each flight design cannot be completed on a practical time scale. The present paper examines specifically a Weibull statistics based stress rupture model and considers the various uncertainties associated with the model parameters. The paper also examines several reliability estimate measures that would be of use for the purpose of recertification and for qualifying flight worthiness of these vessels. Specifically, deterministic values for a point estimate, mean estimate and 90/95 percent confidence estimates of the reliability are all examined for a typical flight quality vessel under constant stress. The mean and the 90/95 percent confidence estimates are computed using Monte-Carlo simulation techniques by assuming distribution statistics of model parameters based also on simulation and on the available data, especially the sample sizes represented in the data. The data for the stress rupture model are obtained from the Lawrence Livermore National Laboratories (LLNL) stress rupture testing program, carried out for the past 35 years. Deterministic as well as probabilistic sensitivities are examined.

  20. Test with different stress measurement methods in two orthogonal bore holes in Aespoe HRL

    Janson, Thomas; Stigsson, Martin [Golder Associates AB, Stockholm (Sweden)


    Within the scope of work, to provide the necessary rock mechanics support for the site investigations, SKB has studied some available pieces of equipment for in situ stress measurements in deep boreholes. A project with the objective to compare three different pieces of equipment for in situ stress measurements under similar conditions has been carried out. The main objective for the project is to compare the three different pieces of equipment for in situ stress measurements and find a strategy for SKB's Site Investigations to determine the state of stress in the rock mass. Two units of equipment use the overcoring method while the third uses the hydraulic fracturing method. The overcoring was performed by AECL, using Deep Door stopper Gauge System (DDGS), and SwedPower, using their triaxial strain measuring instrument (Borre Probe). MeSy Geo Systeme GmbH performed the hydraulic fracturing. The DDGS system is a new method to SKB while the experience of the SwedPower overcoring and the hydraulic fracturing methods are long. The tests were performed in the same orthogonal boreholes at Aespoe Hard Rock Laboratory (HRL), Oskarshamn, Sweden. The measured results have been verified against known conditions at the Aespoe HRL. The results from the three in situ stress measurement methods rose more questions than answers. Which illustrate the complexity to determine the in situ stresses in a rock mass. To understand the difference in results and answer the questions, it was necessary to do deeper investigations such as laboratory tests and theoretical calculations such as geological structure model, analysis of the influence of a nearby fracture, P-wave measurements, uniaxial tests on small cores from the HQ-3 core, theoretical and numerical analyses of the hole bottom (theoretical strains, stress concentrations and microcracking), auditing of DDGS measurements results and assumptions in the DDGS analyse and microscopy investigations on the cores. The following

  1. Measurement of heat treatment induced residual stresses by using ESPI combined with hole-drilling method

    Jie Cheng; Si-Young Kwak; Ho-Young Hwang


    In this study,residual stresses in heat treated specimen were measured by using ESPI(Electronic Speckle-Pattern Interferometry)combined with the hole-drilling method.The specimen,made of SUS 304austenitic stainless steel,was quenched and water cooled to room temperature.Numerical simulation using a hybrid FDM/FEM package was also carried out to simulate the heat treatment process.As a result,the thermal stress fields were obtained from both the experiment and the numerical simulation.By comparision of stress fields,results from the experimental method and numerical simulation well agreed to each other,therefore,it is proved that the presented experimental method is applicable and reliable for heat treatment induced residual stress measurement.

  2. Wall shear stress measurements using a new transducer

    Vakili, A. D.; Wu, J. M.; Lawing, P. L.


    A new instrument has been developed for direct measurement of wall shear stress. This instrument is simple and symmetric in design with small moving mass and no internal friction. Features employed in the design of this instrument eliminate most of the difficulties associated with the traditional floating element balances. Vibration problems associated with the floating element skin friction balances have been found to be minimized by the design features and optional damping provided. The unique design of this instrument eliminates or reduces the errors associated with conventional floating-element devices: such as errors due to gaps, pressure gradient, acceleration, heat transfer and temperature change. The instrument is equipped with various sensing systems and the output signal is a linear function of the wall shear stress. Measurement made in three different tunnels show good agreement with theory and data obtained by the floating element devices.

  3. Mechanical Stress Measurement During Thin-Film Fabrication

    Broadway, David M. (Inventor)


    A method and system are provided for determining mechanical stress experienced by a film during fabrication thereof on a substrate positioned in a vacuum deposition chamber. The substrate's first surface is disposed to have the film deposited thereon and the substrate's opposing second surface is a specular reflective surface. A portion of the substrate is supported. An optical displacement sensor is positioned in the vacuum deposition chamber in a spaced-apart relationship with respect to a portion of the substrate's second surface. During film deposition on the substrate's first surface, displacement of the portion of the substrate's second surface is measured using the optical displacement sensor. The measured displacement is indicative of a radius of curvature of the substrate, and the radius of curvature is indicative of mechanical stress being experienced by the film.

  4. X-ray residual stress measurement of laminated coating layers produced by plasma spraying

    Nishida, Masayuki (Faculty of Engineering, Tokushima Univ. (Japan)); Hanabusa, Takao (Faculty of Engineering, Tokushima Univ. (Japan)); Fujiwara, Haruo (Faculty of Engineering, Tokushima Univ. (Japan))


    The present paper describes residual stress in laminated layers deposited by thermal spraying on a low carbon steel substrate. Laminated layers were made of Al[sub 2]O[sub 3]-NiCr or Al[sub 2]O[sub 3]-NiAl with various combinations of mixing ratios. X-Ray diffraction was used to measure residual stress in the outermost surface layer. The results of finite-element method (FEM) thermal stress analysis were compared with the experimental results of X-ray measurements. From the X-ray stress measurements, tensile residual stress (100-300 MPa) was measured in the as-coated surface layers of all specimens. The effect of annealing on residual stress variation was also examined. In the case of the Al[sub 2]O[sub 3] (100%) layer of the Al[sub 2]O[sub 3]-NiCr system, residual stress of surface layers was not greatly affected by the method of lamination and did not change significantly upon annealing. In contrast, in the layer with mixed Al[sub 2]O[sub 3] and NiAl, residual stress in the as-coated layer was influenced by the mixing ratio of Al[sub 2]O[sub 3] and NiAl. Furthermore, residual stresses were gradually reduced in both the Al[sub 2]O[sub 3] and Ni phase following annealing. FEM calculation revealed that large compressive residual stress (about -2 GPa) was produced in the 100% Al[sub 2]O[sub 3] layer after a full annealing treatment. The value of residual stress depends on the difference between the thermal expansion coefficients of the laminated layers and the substrate. This result was exactly opposite to the experimental results for the fully annealed Al[sub 2]O[sub 3]-NiCr system. However, residual stresses in the mixed layer (Al[sub 2]O[sub 3]-NiAl) depended on the mixing ration of Al[sub 2]O[sub 3] and NiAl. This agrees qualitatively with the experimental results. (orig.)

  5. [Regional and individual factors of stress experience in Germany: results of a representative survey with the perceived stress questionnaire (PSQ)].

    Kocalevent, R-D; Hinz, A; Brähler, E; Klapp, B F


    The aim of the present study was to define, besides prevalence data, regional and individual factors of stress experience in a representative sample of the German general population. Regional factors were examined separately by federal state and the size of the political location. Individual factors were defined according to the severity of the stress experience as well as on the basis of central social factors such as family state, profession and earnings. The Perceived Stress Questionnaire (PSQ), a validated, self-evaluation process for recording a subjective representation of frequency estimates of stress experiences was used. Data acquisition was carried out by a market research institute in a multi-topic questionnaire (N=2,552). Households were selected by the random route procedure, target persons were also selected at random. The prevalence rate for an elevated stress experience was 14.5%, that for a very high stress experience 3.1% of the sample. People without education exhibited the highest rates of stress experience (36.8%), followed by the unemployed (30.6%). Individual and social factors that favour an increased stress experience are a subjectively poor state of health (OR: 3.42) or belonging to the lower social economic status (OR: 1.30). Furthermore, there are indications of regional factors such as size of the location as well as differences between the individual federal states. An east-west comparion did not show any significant differences with regard to stress experiences. In the light of the illness burden associated with chronic stress situations, preventative measures in cases of unemployment or low level of education should be given priority. © Georg Thieme Verlag KG Stuttgart · New York.

  6. Residual stress measurements of 2-phase sprayed coating layer

    Nishida, Masayuki [Kagawa Polytechnic College, Kagawa (Japan); Hanabusa, Takao


    In a series of the already reported single phase metal and ceramic melt sprayed films, on two phase melt sprayed films, their stress and thermal stress changes due to their bending load are tried to test. In order to prepare two phase state, austenitic stainless steel wire is used by a laser melt spraying method. In this method, CO{sub 2} laser is used for a thermal source, and proceeding direction of its laser is selected to cross melt spraying direction. As a result, the following facts can be elucidated. The stress values at {alpha}- and {gamma}-phase in the stainless steel film are linearly responsive to the bending load, and the stress change in {alpha}-phase is smaller than that in {gamma}-phase. In a heat and cool cycle, {alpha}-phase shows a trend of extension with increasing temperature but {gamma}-phase shows a trend of compression inversely. And, stress behavior at {alpha}- and {gamma}-phases in the stainless steel film does not agree with a mixing rule in common two-phase materials. (G.K.)

  7. Measurement of Residual Stress Field of Hardfacing Metal with RE Oxide and Its Numerical Simulation

    杨庆祥; 姚枚


    The temperature and residual stress fields of a medium-high carbon steel, welded by a cracking resistance electrode with rare earth (RE) oxide, were measured by thermo-vision analyzer and X-ray stress analyzer respectively. Meanwhile, the martensitic transformation temperatures of matrix, hard-face welding (hardfacing) metal welded by conventional hardfacing electrode and that welded by cracking resistance electrode with RE oxide were determined. According to the expe rimental data and the thermo-physical, mechanical parameters of materials, finite element method (FEM) of temperature and stress fields was established. In this FEM, the effect of martensitic transformation on residual stress of hardfacing metal of medium-high carbon steel was taken into account. The results show that, by adding RE oxide in the coat of hardfacing electrode, the martensitic trans formation temperature can be decreased, so that the residual tensile stress on the dangerous position can be decreased. Therefore, the cracking resistance of hardfacing metal can be improved.

  8. Coupled stress-strain and electrical resistivity measurements on copper based shape memory single crystals

    Gonzalez Cezar Henrique


    Full Text Available Recently, electrical resistivity (ER measurements have been done during some thermomechanical tests in copper based shape memory alloys (SMA's. In this work, single crystals of Cu-based SMA's have been studied at different temperatures to analyse the relationship between stress (s and ER changes as a function of the strain (e. A good consistency between ER change values is observed in different experiments: thermal martensitic transformation, stress induced martensitic transformation and stress induced reorientation of martensite variants. During stress induced martensitic transformation (superelastic behaviour and stress induced reorientation of martensite variants, a linear relationship is obtained between ER and strain as well as the absence of hys teresis. In conclusion, the present results show a direct evidence of martensite electrical resistivity anisotropy.


    WANGShu-hong; ZUODun-wen; WANGMin; WANGZong-rong


    The integrated structure parts are widely used in aircraft. The distortion caused by residual stresses in thick pre-stretched aluminum plates during machining integrated parts is a common and serious problem. To predict and control the machining distortion, the residual stress distribution in the thick plate must be measured firstly. The modified removal method for measuring residual stress in thick pre-stretched aluminum plates is proposed and the stress-strain relation matrix is deduced by elasticity theory. The residual stress distribution in specimen of 7050T7451 plate is measured by using the method, and measurement results are analyzed and compared with data obtained by other methods. The method is effective to measure the residual stress.

  10. Strain Measurement Using FBG on COPV in Stress Rupture Test

    Banks, Curtis; Grant, Joseph


    White Sands Test Facility (WSTF) was requested to perform ambient temperature hydrostatic pressurization testing of a Space Transportation System (STS) 40-in. Kevlar Composite Overwrapped Pressure Vessel (COPV). The 40-in. vessel was of the same design and approximate age as the STS Main Propulsion System (MPS) and Orbiter Maneuvering System (OMS) vessels. The NASA Engineering Safety Center (NESC) assembled a team of experts and conducted an assessment that involved a review of national Kevlar COPY data. During the review, the STS COPVs were found to be beyond their original certification of ten years. The team observed that the likelihood of STS COPV Stress rupture, a catastrophic burst before leak failure mode, was greater than previously believed. Consequently, a detailed assessment of remaining stress rupture life became necessary. Prior to STS-114, a certification deviation was written for two flights of OV-103 (Discovery) and OV-104 (Atlantis) per rationale that was based on an extensive review of the Lawrence Livermore National Laboratories, COPV data, and revisions to the STS COPV stress levels. In order to obtain flight rationale to extend the certification deviation through the end of the Program, the Orbiter Project Office has directed an interagency COPV team to conduct further testing and analysis to investigate conservatism in the stress rupture model and evaluate material age degradation. Additional analysis of stress rupture life requires understanding the fiber stresses including stress that occurs due to thru-wall composite compression in COPV components. Data must be obtained at both zero gauge pressure (pre-stress) and at the component operating pressure so that this phenomenon can be properly evaluated. The zero gauge pressure stresses are predominantly a result of the autofrettage process used during vessel manufacture. Determining these pre-stresses and the constitutive behavior of the overwrap at pressure will provide necessary information

  11. Modified Layer-Removal Method for Measurement of Residual Stress in Pre-stretched Aluminium Alloy Plate

    Liangbao Liu; Jianfei Sun; Wuyi Chen; Pengfei Sun


    Residual stress is one of the factors affecting the machining deformation of monolithic structure parts in the aviation industry. Thus, the studies on machining deformation rules induced by residual stresses largely depend on correctly and efficiently measuring the residual stresses of workpieces. A modified layer⁃removal method is proposed to measure residual stress by analysing the characteristics of a traditional layer⁃removal method. The coefficients of strain release are then deduced according to the simulation results using the finite element method ( FEM) . Moreover, the residual stress in a 7075T651 aluminium alloy plate is measured using the proposed method, and the results are then analyzed and compared with the data obtained by the traditional methods. The analysis indicates that the modified layer⁃removal method is effective and practical for measuring the residual stress distribution in pre⁃stretched aluminium alloy plates.

  12. Natural Variation in Stress Hormones, Comparisons Across Matrices, and Impacts Resulting from Induced Stress in the Bottlenose Dolphin.

    Houser, Dorian S; Champagne, Cory D; Crocker, Daniel E; Kellar, Nicholas M; Cockrem, John; Romano, Tracy; Booth, Rebecca K; Wasser, Samuel K


    Knowledge regarding stress hormones and how they vary in response to seasonality, gender, age, and reproductive status for any marine mammal is limited. Furthermore, stress hormones may be measured in more than one matrix (e.g., feces, blood, blubber), but the relationships between levels of a given hormone across these matrices are unknown, further complicating the interpretations of hormones measured in samples collected from wild animals. A study is underway to address these issues in a population of bottlenose dolphins trained for voluntary participation in sample collections from different matrices and across season and time of day.

  13. Laser Treatment of HVOF Coating: Modeling and Measurement of Residual Stress in Coating

    Arif, A. F. M.; Yilbas, B. S.


    High-velocity oxy-fuel (HVOF) coating of diamalloy 1005 (similar to Inconel 625 alloy) onto the Ti-6Al-4V alloy is considered and laser-controlled melting of the coating is examined. The residual stress developed after the laser treatment process is modeled using the finite element method (FEM). The experiment is conducted to melt the coating using a laser beam. The residual stress measurement in the coating after the laser treatment process is realized using the XRD technique. The morphological and metallurgical changes in the coating are examined using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). It is found that the residual stress reduces at the coating-base material interface and the residual stress predicted agrees with the XRD measurements. A compact and crack-free coating is resulted after the laser treatment process.

  14. Turbulent stress measurements with phase-contrast magnetic resonance through tilted slices

    MacKenzie, Jordan; Soederberg, Daniel; Lundell, Fredrik [Linne FLOW Centre, KTH Mechanics, Stockholm (Sweden); Swerin, Agne [SP Technical Research Institute of Sweden-Chemistry, Materials and Surfaces, Stockholm (Sweden); KTH Royal Institute of Technology, Surface and Corrosion Science, Stockholm (Sweden)


    Aiming at turbulent measurements in opaque suspensions, a simplistic methodology for measuring the turbulent stresses with phase-contrast magnetic resonance velocimetry is described. The method relies on flow-compensated and flow-encoding protocols with the flow encoding gradient normal to the slice. The experimental data is compared with direct numerical simulations (DNS), both directly but also, more importantly, after spatial averaging of the DNS data that resembles the measurement and data treatment of the experimental data. The results show that the most important MRI data (streamwise velocity, streamwise variance and Reynolds shear stress) is reliable up to at least anti r = 0.75 without any correction, paving the way for dearly needed turbulence and stress measurements in opaque suspensions. (orig.)

  15. Diffraction plane dependence of elastic constants in residual stress measurement by neutron diffraction

    Okido, Shinobu; Hayashi, Makoto [Hitachi Ltd., Tokyo (Japan); Morii, Yukio; Minakawa, Nobuaki; Tsuchiya, Yoshinori


    In a residual stress measurement by x-ray diffraction method and a neutron diffraction method, strictly speaking, the strain measurement of various diffracted surface was conducted and it is necessary to use its elastic modulus to convert from the strain to the stress. Then, in order to establish the residual stress measuring technique using neutron diffraction, it is an aim at first to make clear a diffraction surface dependency of elastic modulus for the stress conversion in various alloys. As a result of investigations the diffraction surface dependency of elastic module on SUS304 and STS410 steels by using RESA (Neutron diffractometer for residual stress analysis) installed at JRR-3M in Tokai Establishment of JAERI, following results are obtained. The elastic modulus of each diffraction surface considering till plastic region could be confirmed to be in a region of {+-}20% of that calculated by Kroner`s model and to be useful for that used on conversion to the stress. And, error of this elastic modulus was thought to cause the transition and defect formed at inner portion of the materials due to a plastic deformation. (G.K.)

  16. Effects of cutting and specimen size on neutron measurement of residual stresses

    Law, M.; Luzin, V.; Kirstein, O.


    To perform neutron residual stress measurements it is often necessary to cut samples to a manageable size. The effects of cutting a girth welded pipe were investigated with analytical methods and finite element analysis. The effect of cutting on measured stresses was calculated. A simplified method of modelling residual stresses in welds, "chill modelling", is introduced. In ring slitting a cut is made in the axial direction and the deformation is maeesured. The change in elastic stress can be calculated and added to neutron diffraction measurements made on a cut ring to calculate the original stresses. Residual stress measurements were performed to validate the ring slitting correction using ANSTO's residual stress diffractometer Kowari.

  17. Mental stress assessment using simultaneous measurement of EEG and fNIRS.

    Al-Shargie, Fares; Kiguchi, Masashi; Badruddin, Nasreen; Dass, Sarat C; Hani, Ahmad Fadzil Mohammad; Tang, Tong Boon


    Previous studies reported mental stress as one of the major contributing factors leading to various diseases such as heart attack, depression and stroke. An accurate stress assessment method may thus be of importance to clinical intervention and disease prevention. We propose a joint independent component analysis (jICA) based approach to fuse simultaneous measurement of electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) on the prefrontal cortex (PFC) as a means of stress assessment. For the purpose of this study, stress was induced by using an established mental arithmetic task under time pressure with negative feedback. The induction of mental stress was confirmed by salivary alpha amylase test. Experiment results showed that the proposed fusion of EEG and fNIRS measurements improves the classification accuracy of mental stress by +3.4% compared to EEG alone and +11% compared to fNIRS alone. Similar improvements were also observed in sensitivity and specificity of proposed approach over unimodal EEG/fNIRS. Our study suggests that combination of EEG (frontal alpha rhythm) and fNIRS (concentration change of oxygenated hemoglobin) could be a potential means to assess mental stress objectively.

  18. Residual stress measurements in the dissimilar metal weld in pressurizer safety nozzle of nuclear power plant

    Campos, Wagner R.C.; Rabello, Emerson G.; Mansur, Tanius R.; Scaldaferri, Denis H.B.; Paula, Raphael G., E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail: [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Souto, Joao P.R.S.; Carvalho Junior, Ideir T., E-mail:, E-mail: [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Metalurgica


    Weld residual stresses have a large influence on the behavior of cracking that could possibly occur under normal operation of components. In case of an unfavorable environment, both stainless steel and nickel-based weld materials can be susceptible to stress-corrosion cracking (SCC). Stress corrosion cracks were found in dissimilar metal welds of some pressurized water reactor (PWR) nuclear plants. In the nuclear reactor primary circuit the presence of tensile residual stress and corrosive environment leads to so-called Primary Water Stress Corrosion Cracking (PWSCC). The PWSCC is a major safety concern in the nuclear power industry worldwide. PWSCC usually occurs on the inner surface of weld regions which come into contact with pressurized high temperature water coolant. However, it is very difficult to measure the residual stress on the inner surfaces of pipes or nozzles because of inaccessibility. A mock-up of weld parts of a pressurizer safety nozzle was fabricated. The mock-up was composed of three parts: an ASTM A508 C13 nozzle, an ASTM A276 F316L stainless steel safe-end, an AISI 316L stainless steel pipe and different filler metals of nickel alloy 82/182 and AISI 316L. This work presents the results of measurements of residual strain from the outer surface of the mock-up welded in base metals and filler metals by hole-drilling strain-gage method of stress relaxation. (author)

  19. Hertzian impact: experimental study of the force pulse and resulting stress waves.

    McLaskey, Gregory C; Glaser, Steven D


    Ball impact has long been used as a repeatable source of stress waves in solids. The amplitude and frequency content of the waves are a function of the force-time history, or force pulse, that the ball imposes on the massive body. In this study, Glaser-type conical piezoelectric sensors are used to measure vibrations induced by a ball colliding with a massive plate. These measurements are compared with theoretical estimates derived from a marriage of Hertz theory and elastic wave propagation. The match between experiment and theory is so close that it not only facilitates the absolute calibration the sensors but it also allows the limits of Hertz theory to be probed. Glass, ruby and hardened steel balls 0.4 to 2.5 mm in diameter were dropped onto steel, glass, aluminum, and polymethylmethacrylate plates at a wide range of approach velocities, delivering frequencies up to 1.5 MHz into these materials. Effects of surface properties and yielding of the plate material were analyzed via the resulting stress waves and simultaneous measurements of the ball's coefficient of restitution. The sensors are sensitive to surface normal displacements down to about +/-1 pm in the frequency range of 20 kHz to over 1 MHz.

  20. Stress effect on conception rate in Nellore cows submmited to fixed time artificial insemination. Preliminary results

    Fábio Luis Nogueira Natal


    Full Text Available In beef cattle, fixed time artificial insemination (FTAI provides a method to inseminate large numbers of females in a specific time, which result in economical gains due, among others, to a more uniform calf crop. However, FTAI requires frequent manipulation of animals in order to inject hormones and for clinical examination. Consequently, animals seemed stressed in less or higher extent at the time of insemination. This can be a problem because it has been demonstrated that application of an acute stress treatment (electric shock, confinement, restraint and rotation twice a day during the follicular phase of the oestrous cycle prevents the pre-ovulatory LH surge. This study aimed to evaluate if FTAI efficiency of Nellore cows is affected by the degree of stress observed at time of AI. Nellore cows (n=92 were treated (Day 0 with a progesterone intravaginal devise (Primer®, Tecnopec, São Paulo, Brazil containing 1 g of progesterone and injected with estradiol benzoate (2mg EB, Estrogin, AUSA, Brazil. Primer was removed on Day 8 (08:00 AM and administered one injection of cloprostenol (125 mcg, Prolise®, Tecnopec, São Paulo, Brazil. Twenty-four hours later, cows received 2 mg EB and insemination (semen from one sire was done on the afternoon (14:00 to 16:00 PM of day 10. At time of FTAI, the stress condition was classified as 1 (low, 2 (moderate or 3 (high according the reactivity of cows to enter in the squeeze chute and apparent nervous behavior. Pregnancy status was evaluated by transrectal ultrasound on day 40 after FTAI. Data were analyzed by Chi-square test. Cows with moderate or high degree of stress had lower conception rate than low stressed cows (P<0.01. These results suggest that cow temperament must be considered in the planning of FTAI programs. Studies are in progress in order to measure hormonal parameters (cortisol and Alpha amylase that better reflects the “fight-or-flight” response to immediate stressors in order to

  1. Water avoidance stress results in an altered voiding phenotype in male mice.

    McGonagle, Erin; Smith, Ariana; Butler, Stephan; Sliwoski, Joanna; Valentino, Rita; Canning, Douglas; Zderic, Stephen A


    We set out to characterize the voiding phenotypes of male mice to a water avoidance stress (WAS) protocol and compare the molecular changes with those induced by surgically induced partial bladder outlet obstruction (pBOO). Six-week-old male Swiss Webster mice housed with sibling littermates were individually placed on a platform centered in the middle of a water filled basin for 1 hr daily for 4 weeks. A non stressed cohort of sibling littermates served as controls. Measured end points included voiding frequency, voided volume, bladder mass, and in vivo cystometry. Molecular end points included myosin heavy chain (MHC) isoform distribution by PCR, and nuclear translocation of hypoxia inducible factor (HIF1α) and the nuclear factor of activated T-cells (NFAT) by gel shift assay. These molecular endpoints were compared with samples from male mice undergoing anatomic pBOO. WAS resulted in increased average voided volumes and bladder mass, and a decrease in voiding frequency (P < 0.05). The slower MHC A isoform was only expressed in the pBOO group that developed severe hypertrophy. Gel shift assays revealed substantial increases in HIF1-α nuclear translocation in the group subjected to pBOO that developed severe hypertrophy but minimal changes in the pBOO group that developed minimal hypertrophy and the swim stress groups. The WAS model induces moderate bladder wall hypertrophy in the absence of any surgical manipulation. Copyright © 2012 Wiley Periodicals, Inc.

  2. A test case of the deformation rate analysis (DRA) stress measurement method

    Dight, P.; Hsieh, A. [Australian Centre for Geomechanics, Univ. of WA, Crawley (Australia); Johansson, E. [Saanio and Riekkola Oy, Helsinki (Finland); Hudson, J.A. [Rock Engineering Consultants (United Kingdom); Kemppainen, K.


    As part of Posiva's site and ONKALO investigations, the in situ rock stress has been measured by a variety of techniques, including hydraulic fracturing, overcoring, and convergence measurements. All these techniques involve direct measurements in a drillhole or at the rock surface. An alternative method is to test drillhole core in a way that enables estimation of the magnitudes and orientations of the in situ rock stress. The Kaiser Effect (KE) and Deformation Rate Analysis (DRA) are two ways to do this. In the work reported here, a 'blind' DRA test was conducted on core obtained from the POSE (Posiva's Olkiluoto Spalling Experiment) niche in the ONKALO. The term 'blind' means that the two first authors of this report, who conducted the tests at the Australian Centre for Geomechanics, did not know the depths below surface at which the cores had been obtained. The results of this DRA Test Case are presented, together with an explanation of the DRA procedure. Also, additional information that would help in such DRA testing and associated analysis is explained. One of the problems in comparing the DRA results with the known Olkiluoto stress field is that the latter is highly variable across the site, as experienced by the previous in situ stress measurements and as predicted by numerical analysis. The variability is mainly caused by the presence of the large brittle deformation zones which perturb the local stress state. However, this variability reduces with depth and the stress field becomes more stable at the {approx} 350 m at which the drillhole cores were obtained. Another compounding difficulty is that the stress quantity, being a second order tensor, requires six independent components for its specification. In other words, comparison of the DRA results and the known stress field requires comparison of six different quantities. In terms of the major principal stress orientation, the DRA results predict an orientation completely

  3. Green space and stress: evidence from cortisol measures in deprived urban communities.

    Roe, Jenny J; Thompson, Catharine Ward; Aspinall, Peter A; Brewer, Mark J; Duff, Elizabeth I; Miller, David; Mitchell, Richard; Clow, Angela


    Contact with green space in the environment has been associated with mental health benefits, but the mechanism underpinning this association is not clear. This study extends an earlier exploratory study showing that more green space in deprived urban neighbourhoods in Scotland is linked to lower levels of perceived stress and improved physiological stress as measured by diurnal patterns of cortisol secretion. Salivary cortisol concentrations were measured at 3, 6 and 9 h post awakening over two consecutive weekdays, together with measures of perceived stress. Participants (n = 106) were men and women not in work aged between 35-55 years, resident in socially disadvantaged districts from the same Scottish, UK, urban context as the earlier study. Results from linear regression analyses showed a significant and negative relationship between higher green space levels and stress levels, indicating living in areas with a higher percentage of green space is associated with lower stress, confirming the earlier study findings. This study further extends the findings by showing significant gender differences in stress patterns by levels of green space, with women in lower green space areas showing higher levels of stress. A significant interaction effect between gender and percentage green space on mean cortisol concentrations showed a positive effect of higher green space in relation to cortisol measures in women, but not in men. Higher levels of neighbourhood green space were associated with healthier mean cortisol levels in women whilst also attenuating higher cortisol levels in men. We conclude that higher levels of green space in residential neighbourhoods, for this deprived urban population of middle-aged men and women not in work, are linked with lower perceived stress and a steeper (healthier) diurnal cortisol decline. However, overall patterns and levels of cortisol secretion in men and women were differentially related to neighbourhood green space and warrant

  4. Residual stress measurement on propellant tank of 2219 aluminum alloy and study on its weak spot

    Huang, Chaoqun; Li, Huan; Li, Jianxiong; Luo, Chuanguang; Ni, Yanbing [Tianjin University, Tianjin (China)


    This paper presented residual stress measurement on two circumferential Variable polarity plasma arc welding (VPPAW) joints and one circular closed Friction stir welding (FSW) joint on the propellant tank of 2219 aluminum alloy using the indentation strain-gauge method. Quite large tensile residual stresses were attached to the center and inner areas of the circular closed FSW joint. There were very large tensile stresses in some points of the two circumferential VPPAW joints, among these points, the maximum value was +253 MPa, which was about 63 % of the yield strength of 410 MPa measured in the base material. In addition, the peak of compressive residual stress was about -160 MPa. Above all, there were two typical peaks of residual stress in the circumferential VPPAW joints, one was located in the middle part while the other one was near the start/end position of the joints. Combining the result of residual stress measurement with the characteristics of the tank structure, it can be concluded that circular closed FSW joint around the flange was a weak spot on the propellant tank. And the most vulnerable point on the circular closed FSW joint has also been found.

  5. On the Determination of Concrete Armour Unit Stress including Specific Results related to Dolosse

    Burcharth, H. F.; Howell, G.L.; Liu, Z.


    Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams for structu......Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams...... for structural integrity. The paper presents a general discussion of the problems related to stress etermination and describes the results and the analyses of model tests with 200 kg and 200 g load-cell instrumented Dolosse. Static stresses, wave-generate stresses due to impacts were studied as well as model...

  6. Retrodiction of a sequence of measurement results in qubit interferometers

    Hillery, Mark; Koch, Daniel


    We study how well we can retrodict results of measurements made on a quantum system if we can make measurements on its final state. We know what measurements were made, but not their results. An initial examination shows that we can gain anywhere from no information to perfect information about the results of previous measurements, depending on the measurements and the initial state of the system. The case of two two-outcome measurements, the second of which is a projective measurement, is examined in some detail. We then look at a model of a qubit interferometer in which measurements are made in order to determine the path the qubit followed. The measurement made on the final state of the qubit depends on the information about previous measurement results that we are trying to determine. One can attempt to find the result of just one of the measurements or all of them or to find a measurement sequence that was not realized. We study all three possibilities.

  7. Reynolds stress scaling in pipe flow turbulence—first results from CICLoPE

    Örlü, R.; Fiorini, T.; Segalini, A.; Bellani, G.; Talamelli, A.; Alfredsson, P. H.


    This paper reports the first turbulence measurements performed in the Long Pipe Facility at the Center for International Cooperation in Long Pipe Experiments (CICLoPE). In particular, the Reynolds stress components obtained from a number of straight and boundary-layer-type single-wire and X-wire probes up to a friction Reynolds number of 3.8×104 are reported. In agreement with turbulent boundary-layer experiments as well as with results from the Superpipe, the present measurements show a clear logarithmic region in the streamwise variance profile, with a Townsend-Perry constant of A2≈1.26. The wall-normal variance profile exhibits a Reynolds-number-independent plateau, while the spanwise component was found to obey a logarithmic scaling over a much wider wall-normal distance than the other two components, with a slope that is nearly half of that of the Townsend-Perry constant, i.e. A2,w≈A2/2. The present results therefore provide strong support for the scaling of the Reynolds stress tensor based on the attached-eddy hypothesis. Intriguingly, the wall-normal and spanwise components exhibit higher amplitudes than in previous studies, and therefore call for follow-up studies in CICLoPE, as well as other large-scale facilities.

  8. Residual stress measurement by successive extension of a slot: A literature review

    Prime, M.B.


    This report reviews the technical literature on techniques that employ successive extension of a slot and the resulting deformations to measure residual stress. Such techniques are known variously in the literature as the compliance or crack compliance method, the successive cracking method, the slotting method, and a fracture mechanics based approach. The report introduces the field and describes the basic aspects of these methods. The report then reviews all literature on the theoretical developments of the method. The theory portion first considers forward method solutions including fracture mechanics, finite element, analytical, and body force methods. Then it examines inverse solutions, including incremental inverses and series expansions. Next, the report reviews all experimental applications of slotting methods. Aspects reviewed include the specimen geometry and material, the details of making the slot, the method used to measure deformation, and the theoretical solutions used to solve for stress. Finally, the report makes a brief qualitative comparison between slotting methods and other residual stress measurement methods.

  9. Development of a New Technique to Assess Susceptibility to Predation Resulting from Sublethal Stresses (Indirect Mortality)

    Cada, G.F.


    Fish that pass through a hydroelectric turbine may not be killed directly, but may nonetheless experience sublethal stresses that will increase their susceptibility to predators (indirect mortality). There is a need to develop reliable tests for indirect mortality so that the full consequences of passage through turbines (and other routes around a hydroelectric dam) can be assessed. We evaluated a new technique for assessing indirect mortality, based on a behavioral response to a startling stimulus (akin to perceiving an approaching predator). We compare this technique to the standard predator preference test. The behavioral response is a rapid movement commonly referred to as a startle response, escape response, or C-shape, based on the characteristic body position assumed by the fish. When viewed from above, a startled fish bends into a C-shape, then springs back and swims away in a direction different from its original orientation. This predator avoidance (escape) behavior can be compromised by sublethal stresses that temporarily stun or disorient the fish. We subjected striped shiners and fathead minnows to varying intensities of either turbulence (10-, 20- or 30-min) or 2-min exposures to a fish anesthetic (100 or 200 mg/L of tricaine methanesulfonate), and evaluated their subsequent behavior. Individual fish were given a startle stimulus and filmed with a high-speed video camera. Each fish was startled and filmed twice before being stressed, and then at 1-, 5-, 15-, and 30-min post-exposure. The resulting image files were analyzed for a variety of behavioral measures including: presence of a response, time to first reaction, duration of reaction, time to formation of maximum C-shape, time to completion of C-shape, and completeness of C-shape. The most immediate measure of potential changes in fish behavior was whether stressed fish exhibited a startle response. For striped shiners, the number of fish not responding to the stimulus was significantly different

  10. Different stress modalities result in distinct steroid hormone responses by male rats

    M.L. Andersen


    Full Text Available Since both paradoxical sleep deprivation (PSD and stress alter male reproductive function, the purpose of the present study was to examine the influence of PSD and other stressors (restraint, electrical footshock, cold and forced swimming, N = 10 per group on steroid hormones in adult Wistar male rats. Rats were submitted to chronic stress for four days. The stressors (footshock, cold and forced swimming were applied twice a day, for periods of 1 h at 9:00 and 16:00 h. Restrained animals were maintained in plastic cylinders for 22 h/day whereas PSD was continuous. Hormone determination was measured by chemiluminescent enzyme immunoassay (testosterone, competitive immunoassay (progesterone and by radioimmunoassay (corticosterone, estradiol, estrone. The findings indicate that PSD (13.7 ng/dl, footshock (31.7 ng/dl and cold (35.2 ng/dl led to lower testosterone levels compared to the swimming (370.4 ng/dl and control (371.4 ng/dl groups. However, progesterone levels were elevated in the footshock (4.5 ng/ml and PSD (5.4 ng/ml groups compared to control (1.6 ng/ml, swimming (1.1 ng/ml, cold (2.3 ng/ml, and restrained (1.2 ng/ml animals. Estrone and estradiol levels were reduced in the PSD, footshock and restraint groups compared to the control, swimming and cold groups. A significant increase in corticosterone levels was found only in the PSD (299.8 ng/ml and footshock (169.6 ng/ml groups. These changes may be thought to be the full steroidal response to stress of significant intensity. Thus, the data suggest that different stress modalities result in distinct steroid hormone responses, with PSD and footshock being the most similar.

  11. A new device designed for direct yield stress measurements of cement spacer

    Gordon, C.L.; Tonmukayakul, P.; Morgan, R.L. [Halliburton Energy Services, Houston, TX (United States)


    The rheological properties of spacer fluids and cement slurries have a significant impact on the hydraulic shear stress of well casing walls. This paper described experimental studies and numerical models of a device designed to measure the yield stress and rheological properties of spacer and cement samples. The device was designed using the Couette principle for rheological measurements, and measured the yield stress of particle-laden samples between 4 and 150 degrees C. A sample contained in a gap between a stator and a blade located along the inside wall of a steel cup was analyzed using the device. A stator was attached to a torque device and remained static during the rheological measurement. Yield stress was measured by rotating the device at a low speed at 3 rpm and at steady state torque. Torque was recorded when the rotation stopped. Two aqueous mixtures of titanium oxide (TiO{sub 2}) particles were used for the experiment. A cement spacer comprised of a blend of barite, citric acid and water was also measured. A volume-averaged shear method was used to calculate shear rate and shear stress. Key dimensionless variables were the impeller Reynolds number; the Froude number; the Weber number; and the Weissenberg number. Accuracy was assessed by examining the data obtained with a model fluid where yield stress data was already determined. Results of the comparison showed that values obtained using the device were consistent and comparable with results obtained using other techniques. It was concluded that further research is needed to characterize the elastic fluids in the device. 13 refs., 2 tabs., 3 figs.

  12. Comparison of stress-measuring techniques at the DNA-UTP site, Rodgers Hollow, Kentucky

    Finley, R.E.


    The Defense Nuclear Agency (DNA) is developing explosives technology through its Underground Technology Program (UTP). Sandia National Laboratories (SNL) has supported the DNA by conducting research to characterize the in situ stress and rock mass deformability at one of the UTP underground sites at Rodgers Hollow, near Louisville, Kentucky on the Fort Knox Military Reservation. The purpose of SNL`s testing was to determine the in situ stress using three different measurement techniques and, if possible, to estimate the rock mass modulus near the underground opening. The three stress-measuring techniques are (1) borehole deformation measurements using overcoring, (2) Anelastic Strain Recovery (ASR) complemented by laboratory ultrasonic and mechanical properties testing, and (3) the in situ flatjack technique using cancellation pressure. Rock mass modulus around the underground opening was estimated using the load deformation history of the flatjack and surrounding rock. Borehole deformation measurements using the overcoring technique probably represent the most reliable method for in situ stress determination in boreholes up to 50 ft (15 m) deep in competent rock around an isolated excavation. The technique is used extensively by the tunneling and mining industries. The ASR technique is also a core-based technique and is used in the petroleum and natural gas industries for characterization of in situ stress from deep boreholes. The flatjack technique has also been used in the tunneling and mining industries, and until recently has been limited to measurement of the stress immediately around the excavation. Results from the flatjack technique must be further analyzed to calculate the in situ stress in the far field.

  13. Uncertainty Quantification and Comparison of Weld Residual Stress Measurements and Predictions.

    Lewis, John R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brooks, Dusty Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    In pressurized water reactors, the prevention, detection, and repair of cracks within dissimilar metal welds is essential to ensure proper plant functionality and safety. Weld residual stresses, which are difficult to model and cannot be directly measured, contribute to the formation and growth of cracks due to primary water stress corrosion cracking. Additionally, the uncertainty in weld residual stress measurements and modeling predictions is not well understood, further complicating the prediction of crack evolution. The purpose of this document is to develop methodology to quantify the uncertainty associated with weld residual stress that can be applied to modeling predictions and experimental measurements. Ultimately, the results can be used to assess the current state of uncertainty and to build confidence in both modeling and experimental procedures. The methodology consists of statistically modeling the variation in the weld residual stress profiles using functional data analysis techniques. Uncertainty is quantified using statistical bounds (e.g. confidence and tolerance bounds) constructed with a semi-parametric bootstrap procedure. Such bounds describe the range in which quantities of interest, such as means, are expected to lie as evidenced by the data. The methodology is extended to provide direct comparisons between experimental measurements and modeling predictions by constructing statistical confidence bounds for the average difference between the two quantities. The statistical bounds on the average difference can be used to assess the level of agreement between measurements and predictions. The methodology is applied to experimental measurements of residual stress obtained using two strain relief measurement methods and predictions from seven finite element models developed by different organizations during a round robin study.

  14. Comparison of local stress values obtained by two measuring methods on blast furnace shell

    P. Bigoš


    Full Text Available This paper describes measuring of time behaviour specified for local stress increments on the blast furnace shell that were performed using strain gauge sensors. These results are compared with values obtained by means of the second specific measuring method. There is also presented in this paper a commentary and discussion concerning the measured time behaviour obtained from the both measuring methods. This article presents results from another of experimental analysis series concerning the blast furnace shell in one concrete metallurgical plant.

  15. A nonnatural head-neck position (Rollkur) during training results in less acute stress in elite, trained, dressage horses.

    van Breda, Eric


    This study measured parameters of stress in recreational, trained horses (REC; n = 7) and elite (International Grand Prix level) trained, dressage horses (DRES; n = 5). The training of the DRES horses uses an unnatural head-neck position (Rollkur), whereas in the REC horses such training techniques are not common. The study measured stress by using heart rate variability analysis for 30 min postfeeding in the morning and 30 min postexercise after a morning training session. The study found no significant difference at rest between the REC and DRES horses. During the posttraining measurements, however, the DRES horses showed, among others, a less sympathetic and increased parasympathetic dominance. These results suggest that DRES horses tend to have less acute stress than do REC horses postexercise. The findings of this study suggest maintaining the health and well-being of DRES horses despite nonnatural, biomechanical positions.

  16. Comparison of measurements and simulation results in 300 mm CZ silicon crystal growth


    A special thermal modeling tool, CrysVUn, which was developed by Crystal Growth Laboratory (CGL) of Fraunhofer Institute of Integrated Systems and Devices Technology in Erlangen of Germany, was used for numerical analysis of growth Interface situation. The heat transportation, argon flow and melt convection have been considered. Cauchy's first and second laws of motion have been the governing partial equations for stress calculation. The measurement results and simulation results were compared and the interface shape and thermal stress distribution during 300 mm Czochralski (CZ) silicon crystal growth with different growth rates were predicted.

  17. Exposure to Early Life Stress Results in Epigenetic Changes in Neurotrophic Factor Gene Expression in a Parkinsonian Rat Model

    Thabisile Mpofana


    Full Text Available Early life adversity increases the risk of mental disorders later in life. Chronic early life stress may alter neurotrophic factor gene expression including those for brain derived neurotrophic factor (BDNF and glial cell derived neurotrophic factor (GDNF that are important in neuronal growth, survival, and maintenance. Maternal separation was used in this study to model early life stress. Following unilateral injection of a mild dose of 6-hydroxydopamine (6-OHDA, we measured corticosterone (CORT in the blood and striatum of stressed and nonstressed rats; we also measured DNA methylation and BDNF and GDNF gene expression in the striatum using real time PCR. In the presence of stress, we found that there was increased corticosterone concentration in both blood and striatal tissue. Further to this, we found higher DNA methylation and decreased neurotrophic factor gene expression. 6-OHDA lesion increased neurotrophic factor gene expression in both stressed and nonstressed rats but this increase was higher in the nonstressed rats. Our results suggest that exposure to early postnatal stress increases corticosterone concentration which leads to increased DNA methylation. This effect results in decreased BDNF and GDNF gene expression in the striatum leading to decreased protection against subsequent insults later in life.

  18. Quantifying Stress in Marine Mammals: Measuring Biologically Active Cortisol in Cetaceans and Pinnipeds


    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Quantifying Stress in Marine Mammals : Measuring...boonstra/ LONG-TERM GOALS This research will improve our ability to measure stress in marine mammals . Stress hormones (glucocorticoids... mammal researchers to measure free glucocorticoid levels. OBJECTIVES This project has two main objectives, both related to improving our

  19. Design and analysis of a toroidal tester for the measurement of core losses under axial compressive stress

    Alatawneh, Natheer; Rahman, Tanvir; Lowther, David A.; Chromik, Richard


    Electric machine cores are subjected to mechanical stresses due to manufacturing processes. These stresses include radial, circumferential and axial components that may have significant influences on the magnetic properties of the electrical steel and hence, on the output and efficiencies of electrical machines. Previously, most studies of iron losses due to mechanical stress have considered only radial and circumferential components. In this work, an improved toroidal tester has been designed and developed to measure the core losses and the magnetic properties of electrical steel under a compressive axial stress. The shape of the toroidal ring has been verified using 3D stress analysis. Also, 3D electromagnetic simulations show a uniform flux density distribution in the specimen with a variation of 0.03 T and a maximum average induction level of 1.5 T. The developed design has been prototyped, and measurements were carried out using a steel sample of grade 35WW300. Measurements show that applying small mechanical stresses normal to the sample thickness rises the delivered core losses, then the losses decrease continuously as the stress increases. However, the drop in core losses at high stresses does not go lower than the free-stress condition. Physical explanations for the observed trend of core losses as a function of stress are provided based on core loss separation to the hysteresis and eddy current loss components. The experimental results show that the effect of axial compressive stress on magnetic properties of electrical steel at high level of inductions becomes less pronounced.

  20. Residual stresses in a quenched superalloy turbine disc: Measurements and modeling

    Rist, M. A.; James, J. A.; Tin, S.; Roder, B. A.; Daymond, M. R.


    A series of neutron diffraction measurements have been carried out to determine the elastic residual strains deep within a large, 40-cm-diameter, forged and water-quenched IN718 aeroengine compressor disc. Neutron path lengths of up to 6 cm were necessary to probe the thickest parts of the forging, and three-dimensional strain and stress components have been derived for the first time in such a large superalloy specimen. Measurements have been compared with the results from a coupled thermal-mechanical finite-element model of the quenching process, based upon appropriate temperature-dependent material properties, with some success. The general residual stress state in the disc is one of near-surface compression, balanced by tension within the disc interior. The steepest stress and strain gradients occur in the transition region from compression to tension, about 1 cm below the surface all around the disc. The largest stress component is in the disc tangential direction and reaches a magnitude of 400 to 500 MPa near the disc surface and at its core. This exceeds the effective yield stress because of the presence of significant hydrostatic stress.

  1. Properties of Swedish posttraumatic stress measures after a disaster.

    Arnberg, Filip K; Michel, Per-Olof; Johannesson, Kerstin Bergh


    This study evaluated the properties of Swedish versions of self-report measures of posttraumatic stress disorder (PTSD), with emphasis on the Impact of Event Scale-Revised (IES-R). Survey data from adult survivors 1, 3, and 6 years after the 2004 Indian Ocean tsunami (n=1506) included the IES-R (from which the IES-6 was derived) and the 12-item General Health Questionnaire (GHQ-12). The PTSD Checklist (PCL) was included in one survey. A structured clinical interview was performed after 6 years (n=142). Factor analyses of the IES-R and PCL indicated that a dysphoric-arousal model provided good fit invariant across assessments. Both measures were accurate in excluding PTSD while all measures provided poorer positive predictive values. The IES-R, but not the IES-6 and GHQ-12, evidenced stability across assessments. In conclusion, the Swedish IES-R and PCL are sound measures of chronic PTSD, and the findings illustrate important temporal aspects of PTSD assessment.

  2. The estimation of the measurement results with using statistical methods

    Velychko, O.; Gordiyenko, T.


    The row of international standards and guides describe various statistical methods that apply for a management, control and improvement of processes with the purpose of realization of analysis of the technical measurement results. The analysis of international standards and guides on statistical methods estimation of the measurement results recommendations for those applications in laboratories is described. For realization of analysis of standards and guides the cause-and-effect Ishikawa diagrams concerting to application of statistical methods for estimation of the measurement results are constructed.

  3. Measurement and modelling of residual stresses in straightened commercial eutectoid steel rods

    Martinez-Perez, M.L. [ICMM, CSIC, Campus de Cantoblanco, E-28049 Madrid (Spain); Borlado, C.R. [ICMM, CSIC, Campus de Cantoblanco, E-28049 Madrid (Spain); Open University, Faculty of Technology, Milton Keynes, MK7 6AL (United Kingdom); Mompean, F.J. [ICMM, CSIC, Campus de Cantoblanco, E-28049 Madrid (Spain); Garcia-Hernandez, M. [ICMM, CSIC, Campus de Cantoblanco, E-28049 Madrid (Spain); Gil-Sevillano, J. [CEIT, Paseo de Manuel Lardizabal 15, E-20018 San Sebastian (Spain); Ruiz-Hervias, J. [Departamento de Ciencia de Materiales, UPM, E.T.S.I. Caminos, Canales y Puertos, c/ Profesor Aranguren s/n, E-28040 Madrid (Spain); Atienza, J.M. [Departamento de Ciencia de Materiales, UPM, E.T.S.I. Caminos, Canales y Puertos, c/ Profesor Aranguren s/n, E-28040 Madrid (Spain)]. E-mail:; Elices, M. [Departamento de Ciencia de Materiales, UPM, E.T.S.I. Caminos, Canales y Puertos, c/ Profesor Aranguren s/n, E-28040 Madrid (Spain); Peng, Ru Lin [NFL Studsvik, Uppsala University, S-61182 Nykoeping (Sweden); Daymond, M.R. [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, K7L 3N6 (Canada)


    Neutron strain scanning measurements on a eutectoid steel rod that has been subjected to standard industrial coiling and straightening operations are presented. Strains were determined non-destructively using two different diffractometers, one at a steady-state neutron source and the other at a pulsed spallation neutron source, with measurements made in both the ferrite and cementite components of the pearlitic microstructure. The residual stress state is explained in terms of a simplified analytical model for a two-phase material, which takes into account the successive loading operations contributing to residual stress. The results show that residual stresses generated by bending-straightening operations are significant and are likely to play an important role in the mechanical properties of the final wires.

  4. Numerical analysis of drilling hole work-hardening effects in hole-drilling residual stress measurement

    Li, H.; Liu, Y. H.


    The hole-drilling strain gage method is an effective semi-destructive technique for determining residual stresses in the component. As a mechanical technique, a work-hardening layer will be formed on the surface of the hole after drilling, and affect the strain relaxation. By increasing Young's modulus of the material near the hole, the work-hardening layer is simplified as a heterogeneous annulus. As an example, two finite rectangular plates submitted to different initial stresses are treated, and the relieved strains are measured by finite element simulation. The accuracy of the measurement is estimated by comparing the simulated residual stresses with the given initial ones. The results are shown for various hardness of work-hardening layer. The influence of the relative position of the gages compared with the thickness of the work-hardening layer, and the effect of the ratio of hole diameter to work-hardening layer thickness are analyzed as well.

  5. Stress-Related Growth in Racial/Ethnic Minority Adolescents: Measurement Structure and Validity

    Vaughn, Allison A.; Roesch, Scott C.; Aldridge, Arianna A.


    Stress-related growth is defined as the perception or experience of deriving benefits from encountering stressful circumstances and, thus, has been identified as a protective factor against stress. The current study revised and subsequently validated scores on an existing measure of stress-related growth in a sample of racial/ethnic minority…

  6. Measurement and Modeling of Job Stress of Electric Overhead Traveling Crane Operators

    Krishna, Obilisetty B.; Maiti, Jhareswar; Ray, Pradip K.; Samanta, Biswajit; Mandal, Saptarshi; Sarkar, Sobhan


    Background In this study, the measurement of job stress of electric overhead traveling crane operators and quantification of the effects of operator and workplace characteristics on job stress were assessed. Methods Job stress was measured on five subscales: employee empowerment, role overload, role ambiguity, rule violation, and job hazard. The characteristics of the operators that were studied were age, experience, body weight, and body height. The workplace characteristics considered were hours of exposure, cabin type, cabin feature, and crane height. The proposed methodology included administration of a questionnaire survey to 76 electric overhead traveling crane operators followed by analysis using analysis of variance and a classification and regression tree. Results The key findings were: (1) the five subscales can be used to measure job stress; (2) employee empowerment was the most significant factor followed by the role overload; (3) workplace characteristics contributed more towards job stress than operator's characteristics; and (4) of the workplace characteristics, crane height was the major contributor. Conclusion The issues related to crane height and cabin feature can be fixed by providing engineering or foolproof solutions than relying on interventions related to the demographic factors. PMID:26929839

  7. The advising alliance for international and domestic graduate students: Measurement invariance and implications for academic stress.

    Rice, Kenneth G; Suh, Hanna; Yang, Xiaohui; Choe, Elise; Davis, Don E


    We expanded the focus of a prior study of international graduate student advising relationships (Rice et al., 2009) to examine advising experiences of both international and domestic students. International (n = 434) and domestic (n = 387) students completed the Advisory Working Alliance Inventory (AWAI-S; Schlosser & Gelso, 2001) and measures of advising experiences, perceived academic stress, and desire to change advisor. Measurement invariance analyses suggested that a 23-item AWAI-S showed support for scalar invariance. A bifactor structure showed superior fit to the 3-factor model or a second-order factor model for the AWAI-S. International and domestic graduate students did not differ in ratings of general alliance, academic stress, or desire to change advisors. General alliance was strongly related to less academic stress and less desire to change advisors. International students who felt disrespected by their advisors were more likely to be academically stressed than domestic students. Structured mentoring experiences were associated with lower stress and less desire to change, and this effect was similar in both international and domestic students. Overall, results suggested that the current level of measurement, and possibly theory development, regarding the advisory alliance is good at identifying generic satisfaction but weaker at differentiating components of the alliance. (c) 2016 APA, all rights reserved).

  8. Mass measurements and nuclear physics - recent results from ISOLTRAP

    Herfurth, F [CERN, 1211 Geneva 23 (Switzerland); Ames, F [Sektion Physik, Ludwig-Maximilians-Universitaet, Muenchen, 85748 Garching (Germany); Audi, G [CSNSM-IN2P3-CNRS, 91405 Orsay-Campus (France); Beck, D [GSI, Planckstrasse 1, 64291 Darmstadt (Germany); Blaum, K [CERN, 1211 Geneva 23 (Switzerland); Bollen, G [NSCL, Michigan State University, East Lansing, MI 48824-1321 (United States); Kellerbauer, A [Sektion Physik, Ludwig-Maximilians-Universitaet, Muenchen, 85748 Garching (Germany); Kluge, H-J [GSI, Planckstrasse 1, 64291 Darmstadt (Germany); Kuckein, M [Sektion Physik, Ludwig-Maximilians-Universitaet, Muenchen, 85748 Garching (Germany); Lunney, D [CSNSM-IN2P3-CNRS, 91405 Orsay-Campus (France); Moore, R B [Department of Physics, McGill University, Montreal (Quebec) H3A 2T8 (Canada); Oinonen, M [Helsinki Institute of Physics, University of Helsinki, PO Box 9, 00014 Helsinki (Finland); Rodriguez, D [GSI, Planckstrasse 1, 64291 Darmstadt (Germany); Sauvan, E [CERN, 1211 Geneva 23 (Switzerland); Scheidenberger, C [GSI, Planckstrasse 1, 64291 Darmstadt (Germany); Schwarz, S [NSCL, Michigan State University, East Lansing, MI 48824-1321 (United States); Sikler, G [GSI, Planckstrasse 1, 64291 Darmstadt (Germany); Weber, C [GSI, Planckstrasse 1, 64291 Darmstadt (Germany)


    The Penning trap mass spectrometer ISOLTRAP is a facility for high-precision mass measurements of short-lived radioactive nuclei installed at ISOLDE/CERN in Geneva. More than 200 masses have been measured with relative uncertainties of 1 x 10{sup -7} or even close to 1 x 10{sup -8} in special cases. This publication gives an overview of the measurements performed with ISOLTRAP and discusses some results.

  9. Future Changes in Heat Stress over East Asia Resulting from Different Target Temperature Increases

    Lee, Sang-Min; Min, Seung-Ki


    In assessing the impact of global warming, it is very important to understand the change in comprehensive heat stress as a function of several variables, rather than only temperature. Furthermore, in order to assess and implement the target temperature goals of the 2015 Paris Agreement, it is essential to have effective and scientifically valid information to predict and measure regional impact. In this study, the future changes in summer heat stress over East Asia were examined based on the Wet-Bulb Globe Temperature (WBGT) using CMIP5 multimodel simulations (historical and RCP scenario simulations), and differences in heat stress changes were assessed between 1.5-degree and 2-degree warmer worlds. Future boreal summer heat stress of land regions over East Asia, in excess of the 50-year return value, shows a rapid and nonlinear increase from the 2000s, and it is expected that severe heat stress will occur in the overall East Asia region by the 2040s. In particular, extreme heat stress events were found to occur much more frequently than summer mean intensity of heat stress. Comparisons of the increase in heat stress between 1.5-degree and 2-degree warmer worlds indicated a 20% decrease in the area experiencing severe heat stress over East Asia, and relatively large benefits (i.e. less frequent and less severe heat stress) were found in the southeastern China, the Korean Peninsula and Japan compared to other regions. Further, the equilibrium scenarios showed a larger increase in heat stress over East Asia than the transient scenarios, particularly in case of the 1.5-degree warmer world, which was found due to warmer water in the northwestern North Pacific in the equilibrium scenarios.

  10. An Estimation Method of Stress in Soft Rock Based on In-situ Measured Stress in Hard Rock

    LI Wen-ping; LI Xiao-qin; SUN Ru-hua


    The law of variation of deep rock stress in gravitational and tectonic stress fields is analyzed based on the Hoek-Brown strength criterion. In the gravitational stress field, the rocks in the shallow area are in an elastic state and the deep, relatively soft rock may be in a plastic state. However, in the tectonic stress field, the relatively soft rock in the shallow area is in a plastic state and the deep rock in an elastic state. A method is proposed to estimate stress values in coal and soft rock based on in-situ measurements of hard rock. Our estimation method relates to the type of stress field and stress state. The equations of rock stress in various stress states are presented for the elastic, plastic and critical states. The critical state is a special stress state, which indicates the conversion of the elastic to the plastic state in the gravitational stress field and the conversion of the plastic to the elastic state in the tectonic stress field. Two cases studies show that the estimation method is feasible.

  11. Using of abrasive water jet for measurement of residual stress in railway wheels

    Hlaváček, P. (Petr); Brumek, J.; Horsák, L.


    The paper provides a general introduction to methods of measurement of residual stresses on railway wheels. Determination of residual stress distribution is necessary for the prediction of wheel service life and possible catastrophic failure. Therefore experimental section is devoted to residual stress measurement using strain gauges according to standard EN 13262 + A1. During measurement, several segments of tested wheel were cut by abrasive water jet to detect changes of residual stresses o...

  12. Results of the First TOF Mass Measurements at NSCL

    Matos, M.; Estrade, A.; Amthor, M.; Bazin, D.; Becerril, A.; Elliot, T.; Galaviz, D.; Gade, A.; Lorusso, G.; Pereira, J.; Portillo, M.; Rogers, A.; Schatz, H.; Stolz, A.; Shapira, D.; Smith, E.; Wallace, M.


    Time-of-Flight mass measurements technique, recently developed at the NSCL, MSU, was used to measure masses of exotic neutron-rich nuclides in the Fe region, important for r-process calculations as well as for calculations of processes occurring in the crust of accreting neutron stars. Results from the experiment will be presented and discussed.

  13. Soil Stress-Strain Behavior: Measurement, Modeling and Analysis

    Ling, Hoe I; Leshchinsky, Dov; Koseki, Junichi; A Collection of Papers of the Geotechnical Symposium in Rome


    This book is an outgrowth of the proceedings for the Geotechnical Symposium in Roma, which was held on March 16 and 17, 2006 in Rome, Italy. The Symposium was organized to celebrate the 60th birthday of Prof. Tatsuoka as well as honoring his research achievement. The publications are focused on the recent developments in the stress-strain behavior of geomaterials, with an emphasis on laboratory measurements, soil constitutive modeling and behavior of soil structures (such as reinforced soils, piles and slopes). The latest advancement in the field, such as the rate effect and dynamic behavior of both clay and sand, behavior of modified soils and soil mixtures, and soil liquefaction are addressed. A special keynote paper by Prof. Tatsuoka is included with three other keynote papers (presented by Prof. Lo Presti, Prof. Di Benedetto, and Prof. Shibuya).

  14. Children's stress during a restorative dental treatment: assessment using salivary cortisol measurements.

    Akyuz, S; Pince, S; Hekin, N


    Dental environment may be a source of stress for the young patient. Such stressful conditions may provoke fear in anxious children. It is well known that stress produces an activation adrenal steroid secretion. Among the methods for assessing child dental fear, measurement of salivary cortisol level is a simple method, because especially in children, sampling of saliva is easy, and cortisol levels in saliva closely mirror serum free cortisol levels, independent of salivary flow rate. For this study, the salivary cortisol levels of 8 children (mean age 5.6 yr) were measured receiving initial dental treatment. Saliva samples were collected via cotton rolls placed to the floor of the mouth at four stages; prior to treatment, during cavitation, placement of the liner and the restoration. Statistical comparison of the results were done by Student-t test. The increase in salivary cortisol levels during cavitation at the first and secondary appointments were significant (p0.05). The results of this study suggest that in restorative procedures, mostly it is the cavitation step that creates stress and anxiety in children. Knowledge of the most stressful condition may be helpful for the dentist to prepare the child to treatment steps.

  15. Measurement invariance of the Depression Anxiety Stress Scales-21 across medical student genders.

    Jafari, Peyman; Nozari, Farnoosh; Ahrari, Forooghosadat; Bagheri, Zahra


    This study aimed to assess whether male and female Iranian medical students perceived the meaning of the items in the Depression Anxiety Stress Scales-21 consistently. A convenience sample of 783 preclinical medical students from the first to sixth semester was invited to this cross-sectional study. Of the 477 respondents, 238 were male and 239 were female. All participants completed the Persian version of the Depression Anxiety Stress Scales-21. The graded response model was used to assess measurement invariance of the instrument across the gender groups. Categorical confirmatory factor analysis was used to evaluate the construct validity of the measure. Moreover, internal consistency was assessed via Cronbach's Alpha. Statistically significant differential item functioning was flagged for just item 6 in the depression subscales (c(2)=6.5, df=1, p=0.011). However, removing or retaining the item 6 in the stress subscale did not change our findings significantly, when we compared stress scores across two genders. The results of categorical confirmatory factor analysis supported the fit of the three-factor model of Depression Anxiety Stress Scales-21. Moreover, Cronbach's alpha was greater than 0.7 in depression, anxiety and stress subscales. This study revealed that Depression Anxiety Stress Scales-21 is an invariant measure across male and female medical students. Hence, this reliable and valid instrument can be used for meaningful comparison of distress scores between medical student genders. Gender comparisons of medical students' psychological profiles provide a better insight into gender influences on the outcome of medical education and medical practice.

  16. Static and dynamic stress analyses of the prototype high head Francis runner based on site measurement

    Huang, X.; Oram, C.; Sick, M.


    More efforts are put on hydro-power to balance voltage and frequency within seconds for primary control in modern smart grids. This requires hydraulic turbines to run at off-design conditions. especially at low load or speed-no load. Besides. the tendency of increasing power output and decreasing weight of the turbine runners has also led to the high level vibration problem of the runners. especially high head Francis runners. Therefore. it is important to carry out the static and dynamic stress analyses of prototype high head Francis runners. This paper investigates the static and dynamic stresses on the prototype high head Francis runner based on site measurements and numerical simulations. The site measurements are performed with pressure transducers and strain gauges. Based on the measured results. computational fluid dynamics (CFD) simulations for the flow channel from stay vane to draft tube cone are performed. Static pressure distributions and dynamic pressure pulsations caused by rotor-stator interaction (RSI) are obtained under various operating conditions. With the CFD results. static and dynamic stresses on the runner at different operating points are calculated by means of the finite element method (FEM). The agreement between simulation and measurement is analysed with linear regression method. which indicates that the numerical result agrees well with that of measurement. Furthermore. the maximum static and dynamic stresses on the runner blade are obtained at various operating points. The relations of the maximum stresses and the power output are discussed in detail. The influences of the boundary conditions on the structural behaviour of the runner are also discussed.

  17. Application of x-ray stress measurement to practical materials for plastic work

    Sekiguchi, Haruo; Kiriyama, Sadao


    X-ray diffraction stress measurement is achieved commonly from calculating elastic strain of crystal lattice. Therefore, the accuracy of the measurement is apt to be influenced from plastic zone or preferred orientation of surface layer for the measurement of practical materials with strong plastic work. It was found that the Two-Axis Oscillation Method was suitable to improve the accuracy of measurement on those materials. This papar discussed on the mechanism of residual stress mode during the process of plastic work, and described the application results on the plastic worked materials, such as spring steel surface treated by shot peening, titanium alloy with preferred orientation and mechanically worked surface of SUS 304 materials.

  18. Methods and results of investigation of the stressed state of rock masses and the development of effective means of controlling mine pressure during underground excavation of ore

    Aitmatov, I.T.; Akhmatov, V.I.; Borshch-Komponiets, V.I.; Vlokh, N.P.; Egorov, P.V.; Kuznetsov, S.V.; Kurlenya, M.V.; Leont' ev, A.V.; Markov, G.A.; Murashev, V.I.


    Experimental and theoretical work conducted in the Soviet Union in determining the stressed state of rock masses and developing underground strata control measures are reviewed. Methods of determining stresses in a rock mass were classified into two groups: mechanical and geophysical. A geodynamic model of the stressed state of the upper layers of the earth's crust was developed based on direct measurements in shafts using methods and apparatus developed in the USSR. Fundamental laws governing the initial stressed state of the earth's crust show that within the limits of a geologically homogeneous block, gravitational and tectonic components of the overall stress field are present with gradients of the stress field and its random components. A study was made of the stress-strain state of chamber roofs; the results made it possible to substantiate the limiting spans of fissured roofs in cleaned chambers.

  19. Method and results of studying conduction measuring transducers

    Dunaevskii, I.G.; Korotkov, B.N.; Povkh, I.L.; Cheplyukov, V.G.


    The method and results are given for determining the sensitivity of conduction measuring transducers with a local magnetic field. The results were obtained by frequency-dependent gradation on a model pulsation velocity gauge--a thermoanemometer. The effect of measuring a transducer's diameter, inter-electrode distance and nose line forms on its spatial resolution capacity was estimated. Adjustment functions were obtained for these transducers. A concept was formulated for measuring transducers belonging to the same class. 5 references, 5 figures.

  20. The cold driver: Cold stress while driving results in dangerous behavior.

    Morris, Drew M; Pilcher, June J


    Cool vehicle cabin temperatures can induce short-term non-hypothermic cold stress. The current study created a cold condition to examine the impact of cold stress on driving behavior. Forty-four participants drove a high-fidelity driving simulator during a thermal neutral or local torso cooled condition. Participants performed additional tasks to assess attention, psychomotor vigilance, and manual dexterity. Skin temperature was significantly lower in the cold condition while internal temperature was unaffected. Participants who had higher subjective ratings of cold followed lead vehicles closer and started to brake later. Participants in the cold condition followed the lead car 22% (0.82s) closer and started braking 20% (2.35s) later when approaching a stop sign during the car-following task. No change in attention, psychomotor vigilance, or dexterity was observed. The current results suggest that cold environmental conditions can contribute to dangerous driving behaviors. Measures of cold perception were also shown to predict changes in driving behavior.

  1. Measuring Bus Drivers' Occupational Stress Under Changing Working Conditions

    Hlotova, Y.; Cats, O.; Meijer, S.A.


    Stress is an immense problem in modern society; approximately half of all occupational illnesses are directly or indirectly related to stress. The work of a bus driver is typically associated with high stress levels that negatively influence individual well-being as well as workforce management. The

  2. Measuring Bus Drivers' Occupational Stress Under Changing Working Conditions

    Hlotova, Y.; Cats, O.; Meijer, S.A.


    Stress is an immense problem in modern society; approximately half of all occupational illnesses are directly or indirectly related to stress. The work of a bus driver is typically associated with high stress levels that negatively influence individual well-being as well as workforce management. The

  3. Basic Study on Estimating Water Stress of a Plant Using Vibration Measurement of Leaf

    Sano, Motoaki; Sugimoto, Tsuneyoshi; Hosoya, Hiroshi; Ohaba, Motoyoshi; Shibusawa, Sakae


    A new noninvasive method for estimating the water stress of a plant was proposed. In order to investigate this method, we first examined the characteristic frequency of an individual leaf picked from the plant, and obtained the result that its characteristic frequency decreased in proportion to the reduction in the water content of the leaf. Next, we applied this method to a leaf on a branch and confirmed the same tendency when the water stress was increased by stopping the water supply of a plant cultured in water. From these results, it was suggested that the water stress of the plant could be estimated from the vibration measurement of the leaf. Lastly, the relationship between the water potential of the leaf and its elastic constant was discussed with the soil-plant-atmosphere-continuum model (SPAC model), and Young's modulus of a tomato leaf was roughly estimated.

  4. Reynolds stress scaling in pipe flow turbulence-first results from CICLoPE.

    Örlü, R; Fiorini, T; Segalini, A; Bellani, G; Talamelli, A; Alfredsson, P H


    This paper reports the first turbulence measurements performed in the Long Pipe Facility at the Center for International Cooperation in Long Pipe Experiments (CICLoPE). In particular, the Reynolds stress components obtained from a number of straight and boundary-layer-type single-wire and X-wire probes up to a friction Reynolds number of 3.8×10(4) are reported. In agreement with turbulent boundary-layer experiments as well as with results from the Superpipe, the present measurements show a clear logarithmic region in the streamwise variance profile, with a Townsend-Perry constant of A2≈1.26. The wall-normal variance profile exhibits a Reynolds-number-independent plateau, while the spanwise component was found to obey a logarithmic scaling over a much wider wall-normal distance than the other two components, with a slope that is nearly half of that of the Townsend-Perry constant, i.e. A2,w≈A2/2. The present results therefore provide strong support for the scaling of the Reynolds stress tensor based on the attached-eddy hypothesis. Intriguingly, the wall-normal and spanwise components exhibit higher amplitudes than in previous studies, and therefore call for follow-up studies in CICLoPE, as well as other large-scale facilities.This article is part of the themed issue 'Toward the development of high-fidelity models of wall turbulence at large Reynolds number'. © 2017 The Author(s).

  5. Measurements of Creep Internal Stress Based on Constant Strain Rate and Its Application to Engineering

    TAO Wen-liang; WEI Tao


    This research is carried out on the basis of Constant Strain Rate(CSR) to measure creep internal stress. Measurements of creep internal stress are conducted on the material test machine by using the CSR method. A mathematical model of creep internal stress is also proposed and its application is presented in this paper.

  6. A new quantitative approach to measure perceived work-related stress in Italian employees.

    Cevenini, Gabriele; Fratini, Ilaria; Gambassi, Roberto


    We propose a method for a reliable quantitative measure of subjectively perceived occupational stress applicable in any company to enhance occupational safety and psychosocial health, to enable precise prevention policies and intervention and to improve work quality and efficiency. A suitable questionnaire was telephonically administered to a stratified sample of the whole Italian population of employees. Combined multivariate statistical methods, including principal component, cluster and discriminant analyses, were used to identify risk factors and to design a causal model for understanding work-related stress. The model explained the causal links of stress through employee perception of imbalance between job demands and resources for responding appropriately, by supplying a reliable U-shaped nonlinear stress index, expressed in terms of values of human systolic arterial pressure. Low, intermediate and high values indicated demotivation (or inefficiency), well-being and distress, respectively. Costs for stress-dependent productivity shortcomings were estimated to about 3.7% of national income from employment. The method identified useful structured information able to supply a simple and precise interpretation of employees' well-being and stress risk. Results could be compared with estimated national benchmarks to enable targeted intervention strategies to protect the health and safety of workers, and to reduce unproductive costs for firms.

  7. FEM Analysis and Measurement of Residual Stress by Neutron Diffraction on the Dissimilar Overlay Weld Pipe

    Kim, Kang Soo; Lee, Ho Jin; Woo, Wan Chuck; Seong, Baek Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Byeon, Jin Gwi; Park, Kwang Soo; Jung, In Chul [Doosan Heavy Industries and Construction Co., Changwon (Korea, Republic of)


    Much research has been done to estimate the residual stress on a dissimilar metal weld. There are many methods to estimate the weld residual stress and FEM (Finite Element Method) is generally used due to the advantage of the parametric study. And the X-ray method and a Hole Drilling technique for an experimental method are also usually used. The aim of this paper is to develop the appropriate FEM model to estimate the residual stresses of the dissimilar overlay weld pipe. For this, firstly, the specimen of the dissimilar overlay weld pipe was manufactured. The SA 508 Gr3 nozzle, the SA 182 safe end and SA376 pipe were welded by the Alloy 182. And the overlay weld by the Alloy 52M was performed. The residual stress of this specimen was measured by using the Neutron Diffraction device in the HANARO (High-flux Advanced Neutron Application ReactOr) research reactor, KAERI (Korea Atomic Energy Research Institute). Secondly, FEM Model on the dissimilar overlay weld pipe was made and analyzed by the ABAQUS Code (ABAQUS, 2004). Thermal analysis and stress analysis were performed, and the residual stress was calculated. Thirdly, the results of the FEM analysis were compared with those of the experimental methods

  8. Computer-assisted measurement of perceived stress: an application for a community-based survey.

    Kimura, Tomoaki; Uchida, Seiya; Tsuda, Yasutami; Eboshida, Akira


    The assessment of stress is a key issue in health promotion policies as well as in treatment strategies for patients. The aim of this study was to confirm the accessibility and reliability of computer-assisted data collection for perceived stress measurement, using the Japanese version of the Perceived Stress Scale (JPSS), within the setting of a community-based survey. There were two groups of participants in this survey. One group responded to a Web-based application, and the other to the VBA of a spreadsheet software. The total scores of JPSS were almost normally distributed. The means of total scores of JPSS were 23.6 and 23.1. These results were lower than the previous study of JPSS. Since Cronbach's alpha coefficients in both surveys were more than 0.8, high reliability was demonstrated despite a number of computer-illiterate and/or aged participants. They felt that the spreadsheet form was easier to respond to. Two components were extracted with the Varimax rotation of principal component analysis, and these were named "perception of stress and stressors" and "behavior to stress". This finding suggests that it is possible to determine sub-scales. From the viewpoint of preventive medicine, it is expected that the JPSS applications will be utilized to investigate the relationship between stress and other factors such as lifestyle, environment and quality of life.

  9. Statistical evaluation of characteristic SDDLV-induced stress resultants to discriminate between undamaged and damaged elements

    Hansen, Lasse Majgaard; Johansen, Rasmus Johan; Ulriksen, Martin Dalgaard


    evaluation of the characteristic stress resultants, hence facilitating general discrimination between damaged and undamaged elements. The three detection methods in question enable outlier analysis on the basis of, respectively, Euclidian distance, Hotelling’s statistics, and Mahalanobis distance. The study...


    Gökmen ATLIHAN


    Full Text Available In this study, the residual stresses in the forming of the seed capsule which used in manifacturing the ferforje was carried out. These residual stresses were made up in the process which bars with 8 mm diameter were converted to 6 x 6 mm2 square profiles. This process was actually a Rolling process performed at three levels. Plastic constant and strain hardening parameter were calculated at each level . Then, elasto-plastic stress analysis of the bar subjected to bending was analzed by means of Newton Cotes formulation. The load value that cause residual stresses on the steel bar was assumed to be constant in elasto-plastic analysis. Elastic, plastic and residual stresses under the load value were determined in each level and results were presented in the graphical format.

  11. Measurement of the stressed state of welded joints in the NPP process components and circulation pipelines based on acoustoelasticity theory

    A.I. Trofimov


    Full Text Available The paper presents the results of a theoretical justification and an experimental research for a method to measure the stressed state of welded joints in the nuclear power plant (NPP process components and circulation pipelines based on acoustoelasticity theory, as well as for ways to implement them technically. Devices for measuring the stressed state of welded joints in the NPP process components and circulation pipelines based on acoustoelasticity theory allow online measurement of residual stresses along the weld height and detection of crack formation points. The use of such devices will enable early crack detection in welded joints for an increased safety of the NPP operation.

  12. The Measurement of Wall Shear Stress in the Low-Viscosity Liquids

    Adamec J.


    Full Text Available The paper is focused on quantitative evaluation of the value of the wall shear stress in liquids with low viscosity by means of the method of the hot film anemometry in a laminar and turbulent flow. Two systems for calibration of probes are described in the paper. The first of these uses an innovative method of probe calibration using a known flow in a cylindrical gap between two concentric cylinders where the inner cylinder is rotated and a known velocity profile and shear rate, or shear stress profile, is calculated from the Navier-Stokes equations. This method is usable for lower values of the wall shear stress, particularly in the areas of laminar flow. The second method is based on direct calibration of the probes using a floating element. This element, with a size of 120x80 mm, is part of a rectangular channel. This method of calibration enables the probe calibration at higher shear rates and is applicable also to turbulent flow. Values obtained from both calibration methods are also compared with results of measurements of the wall shear stress in a straight smooth channel for a certain range of Reynolds numbers and compared with analytical calculations. The accuracy of the method and the influence of various parasitic phenomena on the accuracy of the measured results were discussed. The paper describes in particular the influence of geometric purity of the probe location, the impact of various transfer phenomena, requirements for the measured liquid and layout of the experiment.

  13. In situ stress measurement with the new LVDT - Cell - method description and verification

    Hakala, M. [KMS Hakala Oy, Nokia (Finland); Christiansson, R. [Svensk Kaernbraenslehantering AB, Stockholm (Sweden); Martin, D. [Univ. of Alberta, Edmonton (Canada); Siren, T.; Kemppainen, K.


    Posiva Oy and SKB (Svensk Kaernbraenslehantering AB) tested the suitability a new LVDT-cell (Linear Variable Differential Transducer cell) to measure the induced stresses in the vicinity of an excavated surface and further to use these results to interpret the in situ state of stress. It utilises the overcoring methodology, measuring the radial convergence of four diameters using eight LVDTs, and is similar in concept to the USBM-gauge. A 127 mm diameter pilot-hole is required and the overcore diameter is 200 mm. The minimum overcoring length is 350 mm, and hence a compact drill can be utilised. Extensive testing of the LVDT-cell shows it to be robust and suitable for use in an underground environment. Sensitivity tests also show that the cell can withstand a range of operating conditions and still provide acceptable results. The in situ stress at the measurement location can be solved by numerical inversion using the results of at least three overcoring measurements around the three-dimensional tunnel section. The large dimensions of the measurement tool and the ability to utilise multiple measurements at various locations in a tunnel section, provides flexibility in selecting an appropriate rock mass volume. Because the inversion technique relies on knowing the exact location of the measurements and the geometry profile of the tunnel, modern survey techniques such as Lidar or photogrammetric technology should be used. Checks using traditional surveying techniques should also be used to ensure adequate survey resolution, specially in case of sidecoring measurements. To evaluate the suitability of the LVDT-cell to provide the in situ state of stress, tests were carried out in the drill-and-blast TASS tunnel and TBM tunnel at the Aespoe Hard Rock Laboratory in Sweden. The state of stress established using the LVDT-cell was in agreement with the state of stress established previously using traditional overcoring and hydraulic fracturing methods. In this study, the

  14. Reliable practical technique for in-situ rock stress measurements in deep gold mines.

    Stacey, TR


    Full Text Available The proposed primary output of this research project is the development of a set of equipment and method of in situ stress measurements in a high stress environment typical of the deep level gold mines....

  15. Effect of degree of lipomobilization on results of glucose test in dairy cows in heat stress

    Cincović M.R.


    Full Text Available Cows exposed to heat stress exhibit a decreased ability to mobilize lipids due to increased sensitivity to insulin, which is expressed in a decreased concentration of NEFA. However, certain cows can preserve the level of lipid mobilization after adapting to heat stress. We assumed that cows that have a preserved ability to mobilize lipids are less sensitive to insulin and that they have a lower tolerance for glucose. The aim of this work was to compare the results of an intravenous glucose tolerance test in cows that exhibited, in prolonged heat stress, a decreased (NEFA0.30 mmol/l ability for lipid mobilization. Glucose concentration and NEFA concentration were measured following intravenous application of glucose. The mean glycaemic index value did not differ statistically significantly between the two groups of cows at 10, 15 and 20 minutes after glucose application (p>0.05, but there was a tendency at 10 and 15 minutes for the glycaemia to be higher in cows with preserved lipomobilization (p<0.1. At 30, 60 and 90 minutes after glucose application, glycaemia was statistically significantly higher (p<0.01; p<0.05 and p<0.05 in the group of cows with preserved lipomobilization. The glycaemic index values (mmol/l shown in the same order (30, 60 and 90 minutes were as follows 9.91±0.21: 9.23±0.41; 5.41±0.5: 4.67±0.33 and 4.31±0.39: 3.47±0.37. The mean value for NEFA concentration in samples originating from the two experimental groups of cows did not differ statistically significantly following glucose application. The NEFA concentration showed a tendency to be higher in cows with preserved lipid mobilization in comparison with cows with decreased lipomobilization at 20 and 30 minutes after glucose application (p<0.1. Following the intravenous glucose tolerance test, NEFA and glucose concentrations were in a significant negative correlation, and that correlation was more expressed in cows with decreased lipomobilization. Cows with preserved

  16. Relationship between the onset of depression and stress response measured by the Brief Job Stress Questionnaire among Japanese employees: a cohort study.

    Keiko Wada

    Full Text Available BACKGROUND: The proportion of Japanese workers experiencing intense worry or stress during working life is in excess of 60%, and the incidence of psychiatric disorders and suicide due to psychological burden from work duties is increasing. To confirm whether the stress response measured by the Brief Job Stress Questionnaire (BJSQ can identify risk for depression, a cohort study was conducted to evaluate whether the stress response measured by BJSQ was associated with the onset of depression. METHODS: A total of 1,810 participants aged 20-70 years in 2005 completed the stress response of the BJSQ and were followed-up until August, 2007 by examining sick pay records. Depression was defined by a description in sick pay records that included "depression" or "depressive symptoms" as a reason for sick leave according to a physician's medical certificate. The participants were divided into quartiles (Ql, Q2, Q3, and Q4 according to the total stress response score of BJSQ at baseline. Furthermore, the participants were divided into a higher score category (Q4 and a lower score category (Q1-Q3. Risk ratios of the stress response of the BJSQ for onset of depression were calculated using a multivariable Cox proportional hazard model. RESULTS: Among 1,810 participants, 14 developed depression during a mean of 1.8 years of follow-up. The risk ratio was 2.96 (95% confidence interval [CI], 1.04-8.42, p for trend = 0.002 when the higher stress response score category of BJSQ was compared with the low stress response score category for sick leave due to depression. After adjusting for gender, age, marital status, and having children, the risk ratios were similar to no adjustment. CONCLUSIONS: These findings suggest that the stress response measured by the BJSQ can demonstrate risk for the onset of depression.

  17. Residual Stress Measurement and Calibration for A7N01 Aluminum Alloy Welded Joints by Using Longitudinal Critically Refracted ( LCR) Wave Transmission Method

    Zhu, Qimeng; Chen, Jia; Gou, Guoqing; Chen, Hui; Li, Peng; Gao, W.


    Residual stress measurement and control are highly important for the safety of structures of high-speed trains, which is critical for the structure design. The longitudinal critically refracted wave technology is the most widely used method in measuring residual stress with ultrasonic method, but its accuracy is strongly related to the test parameters, namely the flight time at the free-stress condition ( t 0), stress coefficient ( K), and initial stress (σ0) of the measured materials. The difference of microstructure in the weld zone, heat affected zone, and base metal (BM) results in the divergence of experimental parameters. However, the majority of researchers use the BM parameters to determine the residual stress in other zones and ignore the initial stress (σ0) in calibration samples. Therefore, the measured residual stress in different zones is often high in errors and may result in the miscalculation of the safe design of important structures. A serious problem in the ultrasonic estimation of residual stresses requires separation between the microstructure and the acoustoelastic effects. In this paper, the effects of initial stress and microstructure on stress coefficient K and flight time t 0 at free-stress conditions have been studied. The residual stress with or without different corrections was investigated. The results indicated that the residual stresses obtained with correction are more accurate for structure design.

  18. Wall shear stress measurement method based on parallel flow model near vascular wall in echography

    Shimizu, Motochika; Tanaka, Tomohiko; Okada, Takashi; Seki, Yoshinori; Nishiyama, Tomohide


    A high-risk vessel of arteriosclerosis is detected by assessing wall shear stress (WSS), which is calculated from the distribution of velocity in a blood flow. A novel echographic method for measuring WSS, which aims to distinguish a normal vessel from a high-risk vessel, is proposed. To achieve this aim, the measurement error should be less than 28.8%. The proposed method is based on a flow model for the area near a vascular wall under a parallel-flow assumption to avoid the influences of error factors. This was verified by an in vitro experiment in which the WSS of a carotid artery phantom was measured. According to the experimental results, the WSS measured by the proposed method correlated with the ground truth measured by particle image velocimetry; in particular, the correlation coefficient and measurement error between them were respectively 0.70 and 27.4%. The proposed method achieved the target measurement performance.

  19. Effects of perch access and age on physiological measures of stress in caged White Leghorn pullets.

    Yan, F F; Hester, P Y; Enneking, S A; Cheng, H W


    The neuroendocrine system controls animals' adaptability to their environments by releasing psychotropic compounds such as catecholamines [epinephrine (EP), norepinephrine (NE), and dopamine (DA)], corticosterone (CORT), and serotonin (5-hydroxytryptamine or 5-HT). Changes of these neuroendocrine compounds have been used as biomarkers of animals' stress responses associated with their well-being. Assuming that pullets, like laying hens, are highly motivated to perch, we hypothesize that pullets with access to perches will experience less stress than pullets that never have access to perches. The objective of this study was to examine the effects of perch access and age on physiological measurements of stress in White Leghorn pullets housed in conventional cages. Hatchlings (n = 1,064) were randomly assigned to 28 cages. Two parallel metal round perches were installed in each of 14 cages assigned the perch treatment, whereas control cages were without perches. Two birds per cage were bled at wk 4, 6, and 12 wk of age. Plasma levels of CORT, DA, EP, and NE, blood concentrations of 5-HT and Trp, and heterophil to lymphocyte ratios were measured. Data were analyzed using a 2-way ANOVA. The perch treatment or its interaction with age did not affect any parameter measured in the study. The increase in the concentrations of circulating EP, NE, 5-HT (numerical increase at 4 wk), and Trp in 4- and 6-wk-old pullets compared with 12-wk-old pullets is unclear, but may have been due to acute handling stress at younger ages. In contrast, concentrations of DA were less at 4 wk compared with levels at 6 and 12 wk of age. Plasma CORT levels and the heterophil to lymphocyte ratio, indicators of long-term stress, were unaffected by age (P = 0.07 and 0.49, respectively). These results indicated that age, but not perch access, affects neuroendocrine homeostasis in White Leghorn pullets. Pullets that were never exposed to perches showed no evidence of eliciting a stress response.

  20. Neutron diffraction measurements for the determination of residual stresses in MMC tensile and fatigue specimens

    Fiori, F.; Girardin, E.; Giuliani, A.;


    , residual stresses are present in both the matrix and the particles microstructure, prior to any macroscopic loading. They vary with the temperature and with the type and level of loading imposed to the material, having a strong influence on the mechanical behaviour of MMCs. Neutron diffraction measurements...... have been performed at RISO (Roskilde, DK) and HMI-BENSC (Berlin, D), for the determination of residual stress in AA2124 + 17% SiCp and AA359 + 20% SiCp specimens, submitted to tensile and fatigue tests. For each of the investigated samples, the macrostress has been separated from the elastic...... and thermal mismatch microstresses. The results show that, in general, the main contribution to the stress state of both matrix and reinforcement is given by the thermal microstresses, already existing due to heat treatment prior to mechanical tests. (C) 2000 Elsevier Science B.V. All rights reserved....

  1. Transactional stress and coping theory in accounting for psychological states measures

    V. Buško


    Full Text Available The paper examines a relative predictive value of some stable individual attributes and the processes of cognitive appraisals and coping with stress in accounting for specific components of anxiety state measures. Self-report instruments for the measurement of selected psychological constructs, i.e. perceived incompetence, externality, stress intensity and duration, situation-specific coping strategies, and the two anxiety state components, were taken in a sample of 449 male military basics trainees, ranging in age from 18-27. Hierarchical multiple regression analyses showed that the set of predictors employed could account for statistically, as well as theoretically and practically a significant part of variance in cognitive anxiety component (45,5%, and in visceral-emotional component (32,2% of the anxiety state. The extent of anxiety reactions assessed by both scales could primarily be explained by general perception of personal incompetence, as a relatively stable dimension of general self-concept. Of the ways of coping examined, reinterpretation of stressful events was the only strategy contributing to low level, whereas passivization, wishful thinking, and seeking social support contributed to higher levels of anxiety measured by both scales. The results give partial support to the basic hypotheses on the mediating role of coping in the relationships among particular components of the stress and coping models.

  2. Preliminary results of ground reflectivity measurements using noise radar

    Maślikowski, Łukasz; Krysik, Piotr; Dąbrowska-Zielińska, Katarzyna; Kowalik, Wanda; Bartold, Maciej


    The paper describes experimental L-band ground reflectivity measurement using noise radar demonstrator working as a scatterometer. The radar ground return is usually described with a scattering coefficient, a quantity that is independent from the scatterometer system. To calculate the coefficient in a function of incidence angle, range profile values obtained after range compression were used. In order to improve dynamic range of the measurement, antenna cross-path interference was removed using lattice filter. The ground return was measured at L band both for HH and VV polarizations of radar wave as well as for HV and VH crosspolarizations using log-periodic antennas placed at a 10 m high mast directed towards a meadow surface. In the paper the theoretical considerations, noise radar setup, measurement campaign and the results are described.

  3. Bed shear stress estimation on an open intertidal flat using in situ measurements

    Zhu, Q.; van Prooijen, B. C.; Wang, Z. B.; Ma, Y. X.; Yang, S. L.


    Accurate estimations for the bed shear stress are essential to predict the erosion and deposition processes in estuaries and coasts. This study used high-frequency in situ measurements of water depths and near-bed velocities to estimate bed shear stress on an open intertidal flat in the Yangtze Delta, China. To determine the current-induced bed shear stress (τc) the in situ near-bed velocities were first decomposed from the turbulent velocity into separate wave orbital velocities using two approaches: a moving average (MA) and energy spectrum analysis (ESA). τc was then calculated and evaluated using the log-profile (LP), turbulent kinetic energy (TKE), modified TKE (TKEw), Reynolds stress (RS), and inertial dissipation (ID) methods. Wave-induced bed shear stress (τw) was estimated using classic linear wave theory. The total bed shear stress (τcw) was determined based on the Grant-Madsen wave-current interaction model (WCI). The results demonstrate that when the ratio of significant wave height to water depth (Hs/h) is greater than 0.25, τcw is significantly overestimated because the vertical velocity fluctuations are contaminated by the surface waves generated by high winds. In addition, wind enhances the total bed shear stress as a result of the increases in both τw and τc generated by the greater wave height and reinforcing of vertical turbulence, respectively. From a comparison of these various methods, the TKEw method associated with ESA decomposition was found to be the best approach because: (1) this method generates the highest mean index of agreement; (2) it uses vertical velocities that are less affected by Doppler noise; and (3) it is less sensitive to the near-bed stratification structure and uncertainty in bed location and roughness.

  4. HOMs Simulation and Measurement Results of IHEP02 Cavity

    Zheng, Hongjuan; Zhao, Tongxian; Gao, Jie


    In cavities, there exists not only the fundamental mode which is used to accelerate the beam but also higher order modes (HOMs). The higher order modes excited by beam can seriously affect beam quality, especially for the higher R/Q modes. This paper reports on measured results of higher order modes in the IHEP02 1.3GHz low-loss 9-cell superconducting cavity. Using different methods, Qe of the dangerous modes passbands have been got. The results are compared with TESLA cavity results. R/Q of the first three passbands have also been got by simulation and compared with the results of TESLA cavity.

  5. The measurement of thermal stress distributions along the flow path in injection-molded flat plates

    Hastenberg, C.H.V.; Wildervanck, P.C.; Leenen, A.J.H.; Schennink, G.G.J.


    Internal stresses in injection-molded parts are the result of thermal, flow, and pressure histories. Internal stresses can be roughly divided into thermal and flow-induced stresses. In this paper, a modified layer-removal method is presented to determine thermal stress distributions in injection-mol

  6. Recent results on Higgs measurements and searches in ATLAS

    CERN. Geneva


    The excellent operation of the LHC, and a fast processing and analysis, has enabled ATLAS to produce many new results during the last months with similar or better sensitivity than the one reached during Run 1 of the LHC. The seminar will give an overview of the Standard Model Higgs boson measurements and of searches for non-standard scalar states or decay modes.

  7. Direct measurements of wall shear stress by buried wire gages in a shock-wave boundary-layer interaction region

    Murthy, V. S.; Rose, W. C.


    Detailed measurements of wall shear stress (skin friction) were made with specially developed buried wire gages in the interaction regions of a Mach 2.9 turbulent boundary layer with externally generated shocks. Separation and reattachment points inferred by these measurements support the findings of earlier experiments which used a surface oil flow technique and pitot profile measurements. The measurements further indicate that the boundary layer tends to attain significantly higher skin-friction values downstream of the interaction region as compared to upstream. Comparisons between measured wall shear stress and published results of some theoretical calculation schemes show that the general, but not detailed, behavior is predicted well by such schemes.

  8. On the reliability of neutron diffraction for residual stress measurement in cold-drawn steels

    Ruiz-Hervias, J.; Mompean, F.; Hofmann, M.; Atienza, J. M.


    Residual strains were measured in the ferrite phase of pearlitic steel rods along the radial, axial and hoop directions. Two samples with different initial diameters were subjected to one drawing pass (using same drawing parameters) with 20% section reduction and measured in two different neutron diffraction instruments. The results show that the residual strain state is very similar in both cases, regardless of the diameter of the initial rod. This means that the final residual strain-stress state is unique and it is related to the cold-drawing process parameters. In addition, the results show the reliability of strain scanning with different neutron instruments and experimental conditions.

  9. Measuring nonlinear stresses generated by defects in 3D colloidal crystals

    Lin, Neil Y C; Schall, Peter; Sethna, James P; Cohen, Itai


    The mechanical, structural and functional properties of crystals are determined by their defects and the distribution of stresses surrounding these defects has broad implications for the understanding of transport phenomena. When the defect density rises to levels routinely found in real-world materials, transport is governed by local stresses that are predominantly nonlinear. Such stress fields however, cannot be measured using conventional bulk and local measurement techniques. Here, we report direct and spatially resolved experimental measurements of the nonlinear stresses surrounding colloidal crystalline defect cores, and show that the stresses at vacancy cores generate attractive interactions between them. We also directly visualize the softening of crystalline regions surrounding dislocation cores, and find that stress fluctuations in quiescent polycrystals are uniformly distributed rather than localized at grain boundaries, as is the case in strained atomic polycrystals. Nonlinear stress measurements ...

  10. The Recent Results of the Solar Neutrino Measurement in Borexino

    Koshio, Yusuke


    The recent released results of 153.62 ton year exposure of solar neutrino data in Borexino are here discussed. Borexino is a multi-purpose detector with large volume liquid scintillator, located in the underground halls of the Laboratori Nazionali del Gran Sasso in Italy. The experiment is running since 2007. The first realtime 7Be solar neutrino measurement has been released in 2008. Thanks to the precise detector calibration in 2009, the 7Be flux measurement has been reached with an accuracy better than 5%. The result related to the day/night effect in the $^7$Be energy region is also discussed. These results validate the MSW-LMA model for solar neutrino oscillation.

  11. Recent results from the MISTRAL mass measurement program at ISOLDE

    Lunney, M D; Audi, G; Bollen, G; Borcea, C; Doubre, H; Gaulard, C; Henry, S; De Saint-Simon, M; Thibault, C; Toader, C F; Vieira, N


    The MISTRAL experiment (Mass measurements at ISOLDE with a Transmission and Radiofrequency spectrometer on-Line), conceived for very short-lived nuclides, has reached the end of its commissioning phase. Installed in 1997, results have been obtained consistent with all aspects of the projected spectrometer performance: nuclides with half-lives as short as 30 ms have been measured and accuracies of $\\pm$0.4 have been achieved, despite the presence of a systematic shift and difficulties with isobaric contamination. Masses of several nuclides, including $^{25-26}\\!$Ne and $^{32}$Mg that forms the famous island of inversion around N=20, have been significantly improved.

  12. Results of ionospheric measurements, got on micro satellite "Compass-2"

    Dokukin, Vladimir; Kuznetsov, V. D.; Garipov, G. K.; Kapustina, O.; Mikhailov, Yu. M.; Mikhailova, G. A.; Ruzhin, Yu. Ya.; Sinelnikov, V. M.; Shirokov, A. V.; Yashin, I. V.; Danilkin, V. A.; Degtyar, V. G.

    Results of measurements, executed by complex of scientific instruments of micro satellite Compass-2 in the period of 2006-2007, are presented. The project was aimed on registration and study of ionospheric effects, related to the natural and anthropogenic anomalous phenomena. The effects of interaction of solar wind with magnetosphere in the period of flare activity of the Sun and anomalous low frequency radiations, happened one day before the earthquake with magnitude 4.2, are registered. The data was got on measurements of corpuscular radiation, wide band radiations and low frequency waves along the orbit of satellite.

  13. A therapist-assisted Internet-based CBT intervention for posttraumatic stress disorder: preliminary results.

    Klein, Britt; Mitchell, Joanna; Gilson, Kathryn; Shandley, Kerrie; Austin, David; Kiropoulos, Litza; Abbott, Jo; Cannard, Gwenda


    Posttraumatic stress disorder (PTSD) is a debilitating mental health condition frequently associated with psychiatric comorbidity and diminished quality of life, and it typically follows a chronic, often lifelong, course. Previous research has shown that trauma-related psychopathology (but not necessarily clinical PTSD) can be effectively treated via the Internet. This study is the first of its kind to report on the online treatment of patients with a Diagnostic and Statistical Manual of Mental Disorders (fourth edition) clinical diagnosis of PTSD with therapist support by e-mail only. Preliminary findings are presented of an open trial involving a 10-week Internet-based therapist-assisted cognitive behavioural treatment for PTSD (PTSD Online). Pre and posttreatment measures of PTSD and related symptomatology were compared for 16 participants with a variety of trauma experiences. Participants showed clinically significant reductions in PTSD severity and symptomatology, moderate tolerance of the program content, and high therapeutic alliance ratings. No significant change was found on measures of more general psychological symptoms. The results suggest that PTSD Online appears to be an effective and accessible clinical treatment for people with a confirmed PTSD diagnosis.

  14. General job stress: a unidimensional measure and its non-linear relations with outcome variables.

    Yankelevich, Maya; Broadfoot, Alison; Gillespie, Jennifer Z; Gillespie, Michael A; Guidroz, Ashley


    This article aims to examine the non-linear relations between a general measure of job stress [Stress in General (SIG)] and two outcome variables: intentions to quit and job satisfaction. In so doing, we also re-examine the factor structure of the SIG and determine that, as a two-factor scale, it obscures non-linear relations with outcomes. Thus, in this research, we not only test for non-linear relations between stress and outcome variables but also present an updated version of the SIG scale. Using two distinct samples of working adults (sample 1, N = 589; sample 2, N = 4322), results indicate that a more parsimonious eight-item SIG has better model-data fit than the 15-item two-factor SIG and that the eight-item SIG has non-linear relations with job satisfaction and intentions to quit. Specifically, the revised SIG has an inverted curvilinear J-shaped relation with job satisfaction such that job satisfaction drops precipitously after a certain level of stress; the SIG has a J-shaped curvilinear relation with intentions to quit such that turnover intentions increase exponentially after a certain level of stress.

  15. PIV Measurement of Wall Shear Stress and Flow Structures within an Intracranial Aneurysm Model

    Chow, Ricky; Sparrow, Eph; Campbell, Gary; Divani, Afshin; Sheng, Jian


    The formation and rupture of an intracranial aneurysm (IA) is a debilitating and often lethal event. Geometric features of the aneurysm bulb and upstream artery, such as bulb size, bulb shape, and curvature of the artery, are two groups of factors that define the flow and stresses within an IA. Abnormal flow stresses are related to rupture. This presentation discusses the development of a quasi-3D PIV technique and its application in various glass models at Re = 275 and 550 to experimentally assess at a preliminary level the impact of geometry and flow rate. Some conclusions are to be drawn linking geometry of the flow domain to rupture risk. The extracted results also serve as the baseline case and as a precursor to a companion presentation by the authors discussing the impact of flow diverters, a new class of medical devices. The PIV experiments were performed in a fully index-matched flow facility, allowing for unobstructed observations over complex geometry. A reconstruction and analysis method was devised to obtain 3D mean wall stress distributions and flow fields. The quasi 3D measurements were reconstructed from orthogonal planes encompassing the entire glass model, spaced 0.4mm apart. Wall shear stresses were evaluated from the near-wall flow viscous stresses.

  16. Measuring bed shear stress along vegetated river beds using FST-hemispheres.

    Bockelmann-Evans, B N; Davies, R; Falconer, R A


    The measurement of the bed shear stress along vegetated river beds is essential for accurately predicting the water level, velocity and solute and sediment transport fluxes in computational hydroenvironmental models. Details are given herein of an experimental and theoretical study to determine the bed boundary shear stress along vegetated river beds introducing a novel field measuring method, namely the FliessWasserStammtisch (FST)-hemispheres. Although investigations have been conducted previously for sedimentary channels using the FST-hemispheres, this preliminary study is thought to be the first time that such hemispheres have been used to investigate the bed shear stresses in vegetated channels. FST-hemispheres were first developed by Statzner and Müller [1989. Standard hemispheres as indicators of flow characteristics in lotic benthos research. Freshwater Biology 21, 445-459] to act as an integrated indicator of the gross hydrodynamic stresses present near the bed. Test and validation data were found to be at least of the same order of magnitude for the stresses predicted from literature for sedimentary channels, with this study establishing the commencement of a database of calibrated FST-hemisphere laboratory data for vegetated channel beds. In a series of experiments, depths ranging from 0.1 to 0.28 m were considered, equating directly to comparable conditions in small rivers or streams. The results of this study provide a basis for enabling the FST-hemispheres to be used to evaluate the boundary shear stress for a wider range of applications in the future, including vegetated river beds.

  17. Seasonal Water Storage, the Resulting Deformation and Stress, and Occurrence of Earthquakes in California

    Johnson, C. W.; Burgmann, R.; Fu, Y.; Dutilleul, P.


    In California the accumulated winter snow pack in the Sierra Nevada, reservoirs and groundwater water storage in the Central Valley follow an annual periodic cycle and each contribute to the resulting surface deformation, which can be observed using GPS time series. The ongoing drought conditions in the western U.S. amplify the observed uplift signal as the Earth's crust responds to the mass changes associated with the water loss. The near surface hydrological mass loss can result in annual stress changes of ~1kPa at seismogenic depths. Similarly, small static stress perturbations have previously been associated with changes in earthquake activity. Periodicity analysis of earthquake catalog time series suggest that periods of 4-, 6-, 12-, and 14.24-months are statistically significant in regions of California, and provide documentation for the modulation of earthquake populations at periods of natural loading cycles. Knowledge of what governs the timing of earthquakes is essential to understanding the nature of the earthquake cycle. If small static stress changes influence the timing of earthquakes, then one could expect that events will occur more rapidly during periods of greater external load increases. To test this hypothesis we develop a loading model using GPS derived surface water storage for California and calculate the stress change at seismogenic depths for different faulting geometries. We then evaluate the degree of correlation between the stress models and the seismicity taking into consideration the variable amplitude of stress cycles, the orientation of transient load stress with respect to the background stress field, and the geometry of active faults revealed by focal mechanisms.

  18. Induced damage in Carrara Marble as a result of long-term low-magnitude environmental stresses

    Voigtlaender, Anne; Leith, Kerry; Krautblatter, Michael; Walter, Jens M.


    Damage of intact rock is commonly driven by the interaction of long-term low-magnitude external environmental stresses in combination with surface chemistry, rather than short-term loading in excess of intact rock strength. In order to determine the contribution of environmental stresses to the propagation of micro- and macroscopic fractures under natural environmental conditions we undertook long-term three-point bending tests on large size Carrara Marble specimens. The interaction of mechanical stresses induced by external loading and corrosive conditions (e.g. the presence of water) at the tip of a pre-existing crack is termed stress corrosion. We investigate stress corrosion below saw cut notches in wet and dry samples of Carrara Marble (M1-5, each 10cm x 10cm x 110cm). These were pre-loaded to about 66% of their assumed ultimate strength (determined by the fracture toughness (Kic) calculated for the crack tip). Two marble beams (M1, M3) were initially loaded to 22% and three (M2, M4, M5) to 55% of Kic. CaC03 saturated water was continuously dripped in the notch of samples --M1-4 to create corrosive conditions, while M5 was kept dry. After a three-week bedding period, loading on sample M1 was increased to 55%, M2 and M5 to 77% and M3 and M4 to 85% of Kic respectively. The tests were interrupted prior to failure of the specimens in order to allow the assessment of the crack-tip structure. During the testing period we used classical strain gages and acoustic emission sensors to measure strain and elastic stress changes through coda wave interferometry. Temperature and humidity were monitored and the outflowing fluid was collected for future analysis, throughout. The effect of induced damage on residual intrinsic stresses was evaluated using neutron diffraction on the SALSA instrument at the Institute Laue-Langevin (ILL, Grenoble, France), while texture measurements were undertaken using the X-ray goniometer at the Geoscience Center, University Göttingen, and

  19. Assessing College Student-Athletes' Life Stress: Initial Measurement Development and Validation

    Lu, Frank Jing-Horng; Hsu, Ya-Wen; Chan, Yuan-Shuo; Cheen, Jang-Rong; Kao, Kuei-Tsu


    College student-athletes have unique life stress that warrants close attention. The purpose of this study was to develop a reliable and valid measurement assessing college student-athletes' life stress. In Study 1, a focus group discussion and Delphi method produced a questionnaire draft, termed the College Student-Athletes' Life Stress Scale. In…

  20. Assessing College Student-Athletes' Life Stress: Initial Measurement Development and Validation

    Lu, Frank Jing-Horng; Hsu, Ya-Wen; Chan, Yuan-Shuo; Cheen, Jang-Rong; Kao, Kuei-Tsu


    College student-athletes have unique life stress that warrants close attention. The purpose of this study was to develop a reliable and valid measurement assessing college student-athletes' life stress. In Study 1, a focus group discussion and Delphi method produced a questionnaire draft, termed the College Student-Athletes' Life Stress Scale. In…

  1. Rapid changes in cell physiology as a result of acute thermal stress house sparrows, Passer domesticus.

    Jimenez, Ana G; Williams, Joseph B


    Given that our climate is rapidly changing, Physiological Ecologists have the critical task of identifying characteristics of species that make them either resilient or susceptible to changes in their natural air temperature regime. Because climate change models suggest that heat events will become more common, and in some places more extreme, it is important to consider how extreme heat events might affect the physiology of a species. The implications of more frequent heat wave events for birds have only recently begun to be addressed, however, the impact of these events on the cellular physiology of a species is difficult to assess. We have developed a novel approach using dermal fibroblasts to explore how short-term thermal stress at the whole animal level might affect cellular rates of metabolism. House sparrows, Passer domesticus were separated into a "control group" and a "heat shocked" group, the latter acclimated to 43°C for 24h. We determined the plasticity of cellular thermal responses by assigning a "recovery group" that was heat shocked as above, but then returned to room temperature for 24h. Primary dermal fibroblasts were grown from skin of all treatment groups and the pectoralis muscle was collected. We found that glycolysis (ECAR) and oxygen consumption rates (OCR), measured using a Seahorse XF 96 analyzer, were significantly higher in the fibroblasts from the heat shocked group of House sparrows compared with their control counterparts. Additionally, muscle fiber diameters decreased and, in turn, Na(+)-K(+)-ATPase maximal activity in the muscle significantly increased in heat shocked sparrows compared with birds in the control group. All of these physiological alterations due to short-term heat exposure were reversible within 24h of recovery at room temperature. These results show that acute exposure to heat stress significantly alters the cellular physiology of sparrows, but that this species is plastic enough to recover from such a thermal

  2. Survey of horizontal stresses in coal mines from available measurements and mapping.

    Frith, R


    Full Text Available OF HORIZONTAL STRESS IN THE WITBANK AND HIGHVELD COALFIELDS 21 4.1 Is Horizontal Stress at Work in Roadway Roof Behaviour? 21 4.2 Summary of Measured Horizontal Stresses 24 4.3 Proposed Model for the Origin of Horizontal Stress Within the Coalfields 27 4... effects of horizontal stress could be further mitigated within the practicalities of the mining methods in use. Based on the work undertaken, the following project findings have been arrived at: (a) Horizontal stresses are clearly evident within both...

  3. Comparison of computational analysis with clinical measurement of stresses on below-knee residual limb in a prosthetic socket.

    Zhang, M; Roberts, C


    Interface pressures and shear stresses between a below-knee residual limb and prosthetic socket predicted using finite element analyses were compared with experimental measurements. A three-dimensional nonlinear finite element model, based on actual residual geometry and incorporating PTB socket rectification and interfacial friction/slip conditions, was developed to predict the stress distribution. A system for measuring pressures and bi-axial shear stresses was used to measure the stresses in the PTB socket of a trans-tibial amputee. The FE-predicted results indicated that the peak pressure of 226 kPa occurred at the patellar tendon area and the peak shear stress of 50 kPa at the anterolateral tibia area. Quantitatively, FE-predicted pressures were 11%, on average, lower than those measured by triaxial transducers placed at all the measurement sites. Because friction/slip conditions between the residual limb and socket liner were taken into consideration by using interface elements in the FE model, the directions and magnitudes of shear stresses match well between the FE prediction and clinical measurements. The results suggest that the nonlinear mechanical properties of soft tissues and dynamic effects during gait should be addressed in future work.

  4. Correlation of predicted and measured thermal stresses on an advanced aircraft structure with dissimilar materials. [hypersonic heating simulation

    Jenkins, J. M.


    Additional information was added to a growing data base from which estimates of finite element model complexities can be made with respect to thermal stress analysis. The manner in which temperatures were smeared to the finite element grid points was examined from the point of view of the impact on thermal stress calculations. The general comparison of calculated and measured thermal stresses is guite good and there is little doubt that the finite element approach provided by NASTRAN results in correct thermal stress calculations. Discrepancies did exist between measured and calculated values in the skin and the skin/frame junctures. The problems with predicting skin thermal stress were attributed to inadequate temperature inputs to the structural model rather than modeling insufficiencies. The discrepancies occurring at the skin/frame juncture were most likely due to insufficient modeling elements rather than temperature problems.

  5. Results form RESUME 95. Measurements with mobile equipment

    Lidstroem, K.; Ulvsand, T.; Aagren, G. [National Defence Research Establisment, Div. of Ionising Radiation and Fallout, Umeaa (Sweden)


    This paper presents the results obtained during the NKS, (EKO-3), Exercise Resume-95 by a group from the Division of Ionising Radiation and Fallout, FOA, Umeaa, Sweden. Field gamma measurements were performed in two areas with a HPGe-detector (p-type, 50% relative efficiency) mounted vertically 1 m above the ground or horizontally in a car. One of the areas was an airfield, Vesivehmaa, where 19 measurements were done. The calculated Cs-137 activity was 52.1 {+-} 4.5 kBq/m{sup 2} assuming a two slice distribution model with a homogenous density and activity distribution in each slice. The report contains also the results from a task which included the finding, classification and estimation of the activity of hidden sources within two 10{sup *} 10 m-areas. (au).

  6. Residual stress in hydroxyapatite coating: nonlinear analysis and high-energy synchrotron measurements.

    Fogarassy, Paul; Cofino, Bruno; Millet, Pierre; Lodini, Alain


    The thermal deposition of hydroxyapatite (HA) on titanium alloy substrate (Ti-6A1-4V) leads to a structure that has very good osseointegration properties. However, clinical failures have been occasionally reported at the interface between substrate and coating. Lifetime is the main parameter in such prostheses; therefore, in order to improve their quality, it is necessary to evaluate the level of stresses near the interface. The high-energy synchrotron radiation combines the advantages of a bulk analysis and reduced volume of the gauge. The objective of our study was to calculate the residual stress using a nonlinear finite-element model and to measure residual stress level near the interface, in the hydroxyapatite coating and in titanium alloy substrate with a nondestructive and high-resolution experiment. The high-energy synchrotron radiation of the BM16 beam-line at ESRF (Grenoble-France) was used with a resolution of down to 10 micrometers. The experimental measurements validate the results found by means of nonlinear finite-element analysis of the plasma spraying induced stress.

  7. Development of procedures for the measurement of residual stress by neutron diffraction

    Webster, G A


    Neutron diffraction is a non-destructive method for determining residual stresses in crystalline materials. It is a relatively new technique and no standard is currently available for making these measurements. This paper gives the background to research that has been carried out to develop a standard. It outlines the main findings and indicates the precautions that are required to achieve accurate positioning and alignment of specimens (and components) in a neutron beam and the analysis required to obtain reliable results. It also shows that special attention is needed in dealing with near-surface measurements because of surface aberration. It is demonstrated that, provided the recommended procedures are followed, a positional tolerance of +-0.1 mm can be achieved with an accuracy in strain of propor to 10 sup - sup 4 , to give a resolution in residual stress of propor to 7 to 20 MPa in most materials of practical interest. (orig.)

  8. A system for remote measurements of the wind stress over the ocean

    Large, William G.; Businger, J. A.


    The DISSTRESS system for remote measurements of the surface wind stress over the ocean from ships and buoys is described. It is fully digital, utilizing the inertial dissipation technique. Parallel processing allows anemometer data to be filtered in natural frequency space; that is, the filter cutoffs shift linearly with the mean wind speed of the data to be filtered. The construction of the digital Butterworth bandpass filters is presented in detail. The performance of the system is evaluated by analyzing the results from 28 days of operation during the Frontal Air-Sea Interaction Experiment. The mean wind speed is checked, the anemometer response function is established, and drag coefficients are compared to previous studies. The capability of the system is demonstrated by continuous time series of the friction velocity computed every 20 min. The conclusion is that the surface wind stress can be measured more reliably and accurately (20 percent) with this system than from anemometer wind speeds and a bulk formula.

  9. Influence of Perceived Stress on Incident Amnestic Mild Cognitive Impairment: Results From the Einstein Aging Study.

    Katz, Mindy J; Derby, Carol A; Wang, Cuiling; Sliwinski, Martin J; Ezzati, Ali; Zimmerman, Molly E; Zwerling, Jessica L; Lipton, Richard B


    Stress is a potentially remediable risk factor for amnestic mild cognitive impairment (aMCI). Our objective is to determine whether perceived stress predicts incident aMCI and to determine if the influence of stress on aMCI is independent of known aMCI risk factors, particularly demographic variables, depression, and apolipoprotein genotype. The Einstein Aging Study is a longitudinal community-based study of older adults. The Perceived Stress Scale (PSS) was administered annually in the Einstein Aging Study to participants (N=507; 71 developed incident aMCI; mean follow-up time=3.6 y, SD=2.0) who were aged 70 years and older, free of aMCI and dementia at baseline PSS administration, and had at least 1 subsequent annual follow-up. Cox hazard models were used to examine time to aMCI onset adjusting for covariates. High levels of perceived stress are associated with a 30% greater risk of incident aMCI (per 5-point increase in PSS: hazard ratio=1.30; 95% confidence interval, 1.08-1.58) independent of covariates. The consistency of results after covariate adjustment and the lack of evidence for reverse causation in longitudinal analyses suggest that these findings are robust. Understanding of the effect of perceived stress on cognition may lead to intervention strategies that prevent the onset of aMCI and Alzheimer dementia.

  10. Stress Measurement with an Improved Hollow Inclusion Technique In Jinchuan Nickel Mine


    Borehole overcoring stress measurement with an improved hollow inclusion technique was carried out at 10 points on 3 levels in Jinchuan nickel mine which is situated in north-west of China. Through the measurement, 3-D in situ stress state at the measuring points and distribution characteristics of the stress field in the mine were obtained. The stress state in Jinchuan mine is dominated by the horizontal tectonic stress field. The maximum principal stress is horizontal which is about twice the weight of the overburden and its orientation is approximately vertical to the regional tectonic line. The difference between two horizontal principal stresses is quite large which is an important reason to cause failure of underground excavations.

  11. Current regional stress field and the resultant crustal deformation in SE Korea and their tectonic implication

    Kim, M. C.; Cho, H.; Son, M.


    To determine current regional stress field and to characterize the resultant crustal deformation in SE Korea, Quaternary fault, focal mechanism, and geotechnical in-situ stress data were synthetically analyzed. The Quaternary faults are extensively observed along major inherited fault zones and show compatible orientations with general trends of the inherited faults. Most of the Quaternary faults have a top-to-the-west thrust geometry and kinematics and show a tendency of upward-decreasing dip angle and upward-narrowing gouge zone. Slip-sense indicators and paleo-stress field reconstructions indicate that the faults resulted from reverse or transpressional faulting under an E-W compression. All the magnetic fabrics (AMS) of the fault gouges also indicate the prevailing reverse-slip faulting under an ENE-WNW compression. The dominant oblate magnetic fabrics parallel to fault plane and the degrees of anisotropy increasing in proportion to their oblatenesses indicate that the fabrics have formed by a progressive deformation due to continuous simple shear during the last reactivation stage as reverse faulting. The focal mechanism study in and around the Korean Peninsula show the horizontally clustered P-axes in ENE-WSW direction and the girdle-distributed T-axes in NNW trend. The geotechnical in-situ stress data in south Korea also show NE- or ENE-trending maximum horizontal stress. The current crustal deformation in Korea thus can be characterized by contractional structures produced under a regional E-W or ENE-WSW compression stress field, and most of the Quaternary faults resulted from the local re-activation of appropriately oriented inherited major faults. Considering the tectonic setting and structural features in Asia during the Neogene, the current stress regime is interpreted to have been caused by the cooperation of westward shallow subduction of Pacific Plate and collision of Indian and Eurasian continents since about 5-3.5 Ma.

  12. Clinical usefulness of carotid ultrasonography in patients with an inconclusive exercise treadmill stress test result.

    Karabay, Can Yucel; Kocabay, Gonenc; Guler, Ahmet; Kalayci, Arzu; Akgun, Taylan; Kirma, Cevat


    Although a treadmill exercise stress testing (EST) is often the first-line screening procedure for subjects with an intermediate probability of coronary artery disease (CAD), one limitation of this test is the high rate of inconclusive tests that result from borderline exercise-induced ST changes. The carotid intima media thickness (CIMT) correlates well with atherosclerosis. The purpose of this study was to evaluate the clinical usefulness of performing CIMT measurements in patients with an inconclusive EST. Symptomatic patients without history of vascular disease and with inconclusive EST result were included. Inconclusive results were defined as the presence of horizontal or downsloping ST-segment depression between 0.5 and 0.9 mm or 1.0 and 1.4 mm upsloping ST-segment depression. After inconclusive EST regarding electrocardiographic changes, the measurements of the CIMT and myocardial perfusion imaging study (MPS) were performed in all patients. The CIMT was measured at the posterior wall of the common carotid artery. The diagnosis of CAD was based on the presence of reversible perfusion defects on exercise MPS. A total of 87 patients (57 men) with a mean age of 58.9 ± 7.2 years were enrolled. The MPS was positive in 18 patients. The CIMT in patients with positive MPS was significantly greater than in patients with negative MPS. The CIMT was 0.82 ± 0.33 mm in patients with positive MPS and 0.63 ± 0.21 mm in patients with negative MPS (p = 0.004). Receiver operating characteristic curve analyses revealed that the greatest specificity was obtained when the cut-off value of CIMT was set at 0.66 mm (sensitivity 39%; specificity 72.5%; positive predictive value 27%; negative predictive value 82%). In patients with inconclusive electrocardiographic changes during EST, CIMT was a useful measurement to prevent alternative more expensive and invasive tests. Additionally, mean CIMT is useful for screening patients with an inconclusive EST result to exclude CAD

  13. Measurement and modeling of bed shear stress under solitary waves

    Jayakumar, S.; Guard, P.A.; Baldock, T.E.

    convolution integration methods forced with the free stream velocity and incorporating a range of eddy viscosity models. Wave friction factors were estimated from skin shear stress at different instances over the wave (viz., time of maximum positive total...

  14. Probability distributions of continuous measurement results for conditioned quantum evolution

    Franquet, A.; Nazarov, Yuli V.


    We address the statistics of continuous weak linear measurement on a few-state quantum system that is subject to a conditioned quantum evolution. For a conditioned evolution, both the initial and final states of the system are fixed: the latter is achieved by the postselection in the end of the evolution. The statistics may drastically differ from the nonconditioned case, and the interference between initial and final states can be observed in the probability distributions of measurement outcomes as well as in the average values exceeding the conventional range of nonconditioned averages. We develop a proper formalism to compute the distributions of measurement outcomes, and evaluate and discuss the distributions in experimentally relevant setups. We demonstrate the manifestations of the interference between initial and final states in various regimes. We consider analytically simple examples of nontrivial probability distributions. We reveal peaks (or dips) at half-quantized values of the measurement outputs. We discuss in detail the case of zero overlap between initial and final states demonstrating anomalously big average outputs and sudden jump in time-integrated output. We present and discuss the numerical evaluation of the probability distribution aiming at extending the analytical results and describing a realistic experimental situation of a qubit in the regime of resonant fluorescence.

  15. Short and long term measures of anxiety exhibit opposite results.

    Ehud Fonio

    Full Text Available Animal models of human diseases of the central nervous system, generalized anxiety disorder included, are essential for the study of the brain-behavior interface and obligatory for drug development; yet, these models fail to yield new insights and efficacious drugs. By increasing testing duration hundredfold and arena size tenfold, and comparing the behavior of the common animal model to that of wild mice, we raise concerns that chronic anxiety might have been measured at the wrong time, for the wrong duration, and in the wrong animal. Furthermore, the mice start the experimental session with a short period of transient adaptation to the novel environment (habituation period and a long period reflecting the respective trait of the mice. Using common measures of anxiety reveals that mice exhibit opposite results during these periods suggesting that chronic anxiety should be measured during the post-habituation period. We recommend tools for measuring the transient period, and provide suggestions for characterizing the post habituation period.

  16. Reliable cost effective technique for in situ ground stress measurements in deep gold mines.

    Stacey, TR


    Full Text Available percussion boreholes drilled with a conventional jackhammer • creating the enlargement, or stress/strain change, not by overcoring,but by drilling parallel, overlapping holes • control of the direction of adjacent holes, and prevention of movement... of drill chips into the measuring hole, by means of a special borehole guide • measurement of deformation changes in the first borehole, as a result of the drilling of the third borehole, by means of a borehole deformation meter • sequential deformation...

  17. Results from the BABAR Fully Inclusive Measurement of B? Xs?

    Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Tisserand, V.; Zghiche, A.; /Annecy, LAPP; Grauges, E.; /Barcelona, IFAE; Palano, A.; Pappagallo, M.; Pompili, A.; /Bari U. /INFN, Bari; Chen, J.C.; Qi, N.D.; Rong, G.; Wang, P.; Zhu, Y.S.; /Beijing, Inst. High Energy Phys.; Eigen, G.; Ofte, I.; Stugu, B.


    We present preliminary results from a lepton-tagged fully-inclusive measurement of B {yields} X{sub s}{gamma} decays, where X{sub s} is any strange hadronic state. Results are based on a BABAR data set of 88.5 million B{bar B} pairs at the {Upsilon}(4S) resonance. We present a reconstructed photon energy spectrum in the {Upsilon}(4S) frame, and partial branching fractions above minimum reconstructed photon energies of 1.9, 2.0, 2.1 and 2.2 GeV. We then convert these to measurements of partial branching fractions and truncated first and second moments of the true photon energy distribution in the B rest frame, above the same minimum photon energy values. The full correlation matrices between the first and second moments are included to allow fitting to any parameterized theoretical calculation. We also measure the direct CP asymmetry {Alpha}{sub CP}(B {yields} X{sub s+d{gamma}}) (based on the charge of the tagging lepton) above a reconstructed photon energy of 2.2 GeV.

  18. Results from the BABAR Fully Inclusive Measurement of B? Xs?

    Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Tisserand, V.; Zghiche, A.; /Annecy, LAPP; Grauges, E.; /Barcelona, IFAE; Palano, A.; Pappagallo, M.; Pompili, A.; /Bari U. /INFN, Bari; Chen, J.C.; Qi, N.D.; Rong, G.; Wang, P.; Zhu, Y.S.; /Beijing, Inst. High Energy Phys.; Eigen, G.; Ofte, I.; Stugu, B.


    We present preliminary results from a lepton-tagged fully-inclusive measurement of B {yields} X{sub s}{gamma} decays, where X{sub s} is any strange hadronic state. Results are based on a BABAR data set of 88.5 million B{bar B} pairs at the {Upsilon}(4S) resonance. We present a reconstructed photon energy spectrum in the {Upsilon}(4S) frame, and partial branching fractions above minimum reconstructed photon energies of 1.9, 2.0, 2.1 and 2.2 GeV. We then convert these to measurements of partial branching fractions and truncated first and second moments of the true photon energy distribution in the B rest frame, above the same minimum photon energy values. The full correlation matrices between the first and second moments are included to allow fitting to any parameterized theoretical calculation. We also measure the direct CP asymmetry {Alpha}{sub CP}(B {yields} X{sub s+d{gamma}}) (based on the charge of the tagging lepton) above a reconstructed photon energy of 2.2 GeV.

  19. Results from power quality measurements in Germany - An overview

    Gerdes, G.J.; Santjer, F. [German Wind Energy Inst, Wilhelmshaven (Germany)


    Grid interferences caused by wind turbines (WT) are getting a severe problem in Germany with the fast increasing number of installed turbines. The wind energy capacity was doubled annually in the past three years. The actual situation and the plannings for the next years will lead to a situation, where high wind energy penetration will exercise a big influence on the power and voltage quality of local utility networks. Measurements performed in Germany according to a national guideline show a big variety in power quality performance of WT`s, which does affect the requirements for grid connection and thus the economical situation of wind energy projects to a large extent. The results from more than 25 power quality measurements will be discussed in this paper. 5 refs., 5 figs., 1 tab.

  20. Measuring 35S of Aerosol Sulfate: Techniques and First Results

    Brothers, L. A.; Dominguez, G.; Bluen, B.; Corbin, A.; Abramian, A.; Thiemens, M. H.


    On a global and regional level, the cycling of sulfur in the environment has consequences for air quality, human health, and may contribute to global climate change. Due to its multiple oxidation states, the sulfur cycle is very complex and poorly understood. Stable isotopes are currently used to understand reaction pathways as well as sources and sinks of sulfurous compounds in the environment. Sulfur also has one short lived (τ1/2 ~87 d) radioactive isotope (35S) which is continuously made in the atmosphere by the cosmic ray spallation of argon, is then quickly oxidized to 35SO2 and enters the atmospheric sulfur cycle. The short-lived radioactive nature of this isotope of sulfur provides us with potentially powerful tracer for understanding the time scales at which sulfur is oxidized, deposited, and transported in the atmosphere and the deposition of atmospheric sulfate into rivers and water catchments. However, despite its potential, the use of 35S as a tracer of aerosol chemistry has not been fully exploited, Here we present details of instrumental set up for measuring 35S in aerosol sulfate and some preliminary results of measurements of 35S abundances in aerosols from Riverside (inland) and La Jolla (coastal) CA and discuss the sensitivity and limitations of the measurements in providing insights into day/night aerosol chemistry (Riverside) as well as the uptake of SO2 pollution in coastal environments by sea-salt aerosols. Also, we present preliminary results from measurement of sulfate in river water in Ecuador before and after precipitation events.

  1. A photoelastic measurement system for residual stress analysis in scintillating crystals by conoscopic imaging.

    Montalto, L; Paone, N; Scalise, L; Rinaldi, D


    The assessment of the stress state of scintillating crystals is an important issue for producers as well as users of such materials, because residual stress may arise during growth process. In this paper, a measurement system, based on the use of a photoelastic, conoscopic optical setup, is proposed for the assessment of stress state in scintillating crystals. Local stress values can be measured on the crystal in order to observe their spatial distribution. With the proposed system, it is possible to vary the dimensions of the inspected measurement volume. It has been validated with reference to a known stress state induced in a birefringent crystal sample and it has been tested for the case of loaded and unloaded samples, showing sub-millimetric spatial resolution and stress uncertainty ≤0.25 MPa. The proposed measurement system is a valid method for the inspection of scintillating crystals required by producers and users of such materials.

  2. Structural integrity assessment and stress measurement of CHASNUPP-1 fuel assembly

    Waseem,, E-mail:; Murtaza, Ghulam; Elahi, Nadeem


    Highlights: • Finite element model of CHASNUPP-1 fuel assembly produced, using Shell181 elements. • Non-linear contact and buckling analysis have been performed. • Structural integrity and stress measurement of fuel assembly is calculated. • Calculated stresses and deformations, are compared with test results. • Results of both studies are comparable, which validate finite element methodology. - Abstract: Fuel assembly of the PWR nuclear power plant is a long and flexible structure. This study has been made in an attempt to find the structural integrity of the fuel assembly (FA) of Chashma Nuclear Power Plant-1 (CHASNUPP-1) at room temperature in air. Non-linear contact and buckling analyses have been performed using ANSYS 13.0, in-order to determine the FA's deformation behaviour as well as the location/values of the maximum stress intensity and stresses developed in axial direction under applied compression load of 7350 N or 1.6 g being the FA's handling load (Zhang et al., 1994). The finite element (FE) model comprises spacer grids, fuel rods, flexible contact between the fuel rods and grids’ supports system (springs and dimples) and guide thimbles with dash-pots and flow holes, in addition to the spot welds between spacer grids and guide thimbles, has been developed using Shell181, Conta174 and Targe170 elements. FA is a non-straight structure. The actual behaviour of the geometry is non-linear. The value of the perturbation force is related to the geometry of the model and/or the tolerance defined for the geometry. Therefore, a sensitivity study has been made to determine the appropriate value of an arbitrary perturbation load. It has been observed that FA deformation values obtained through FE analysis and experiment (SNERDI Tech Doc, 1994) under applied compression load are comparable and show linear behaviours. Therefore, it is confirmed that buckling of FA will not occur at the specified load. Moreover, the values of stresses obtained

  3. Measuring systems of hard to get objects: problems with analysis of measurement results

    Gilewska, Grazyna


    The problem accessibility of metrological parameters features of objects appeared in many measurements. Especially if it is biological object which parameters very often determined on the basis of indirect research. Accidental component predominate in forming of measurement results with very limited access to measurement objects. Every measuring process has a lot of conditions limiting its abilities to any way processing (e.g. increase number of measurement repetition to decrease random limiting error). It may be temporal, financial limitations, or in case of biological object, small volume of sample, influence measuring tool and observers on object, or whether fatigue effects e.g. at patient. It's taken listing difficulties into consideration author worked out and checked practical application of methods outlying observation reduction and next innovative methods of elimination measured data with excess variance to decrease of mean standard deviation of measured data, with limited aomunt of data and accepted level of confidence. Elaborated methods wee verified on the basis of measurement results of knee-joint width space got from radiographs. Measurements were carried out by indirectly method on the digital images of radiographs. Results of examination confirmed legitimacy to using of elaborated methodology and measurement procedures. Such methodology has special importance when standard scientific ways didn't bring expectations effects.

  4. Finite element analysis and measurement for residual stress of dissimilar metal weld in pressurizer safety nozzle mockup

    Lee, Kyoung Soo; Kim, W.; Lee, Jeong Geun; Park, Chi Yong; Yang, Jun Seok; Kim, Tae Ryong [Korea Electric Power Research Institute, Daejeon (Korea, Republic of); Park, Jai Hak [Chungbuk University, Cheongju (Korea, Republic of)


    Finite element (FE) analysis and experiment for weld residual stress (WRS) in the pressurizer safety nozzle mockup is described in various processes and results. Foremost of which is the dissimilar simulation metal welding (DMW) between carbon steel and austenitic stainless steel. Thermal and structural analyses were compared with actual residual stress, and actual measurements of. Magnitude and distribution of WRS in the nozzle mockup were assessed. Two measurement methods were used: hole-drilling method (HDM) with strain gauge for residual stress on the surface of the mockup, and block removal and splitting layer (BRSL) method for through-thickness. FE analysis and measurement data showed good agreement. In conclusion, the characteristics of weld residual stress of DMW could be well understood and the simplified FE analysis was verified as acceptable for estimating WRS

  5. How integrated are behavioral and endocrine stress response traits? A repeated measures approach to testing the stress-coping style model.

    Boulton, Kay; Couto, Elsa; Grimmer, Andrew J; Earley, Ryan L; Canario, Adelino V M; Wilson, Alastair J; Walling, Craig A


    It is widely expected that physiological and behavioral stress responses will be integrated within divergent stress-coping styles (SCS) and that these may represent opposite ends of a continuously varying reactive-proactive axis. If such a model is valid, then stress response traits should be repeatable and physiological and behavioral responses should also change in an integrated manner along a major axis of among-individual variation. While there is some evidence of association between endocrine and behavioral stress response traits, few studies incorporate repeated observations of both. To test this model, we use a multivariate, repeated measures approach in a captive-bred population of Xiphophorus birchmanni. We quantify among-individual variation in behavioral stress response to an open field trial (OFT) with simulated predator attack (SPA) and measure waterborne steroid hormone levels (cortisol, 11-ketotestosterone) before and after exposure. Under the mild stress stimulus (OFT), (multivariate) behavioral variation among individuals was consistent with a strong axis of personality (shy-bold) or coping style (reactive-proactive) variation. However, behavioral responses to a moderate stressor (SPA) were less repeatable, and robust statistical support for repeatable endocrine state over the full sampling period was limited to 11-ketotestosterone. Although post hoc analysis suggested cortisol expression was repeatable over short time periods, qualitative relationships between behavior and glucocorticoid levels were counter to our a priori expectations. Thus, while our results clearly show among-individual differences in behavioral and endocrine traits associated with stress response, the correlation structure between these is not consistent with a simple proactive-reactive axis of integrated stress-coping style. Additionally, the low repeatability of cortisol suggests caution is warranted if single observations (or indeed repeat measures over short sampling

  6. Residual stress measurement in a metal microdevice by micro Raman spectroscopy

    Song, Chang; Du, Liqun; Qi, Leijie; Li, Yu; Li, Xiaojun; Li, Yuanqi


    Large residual stress induced during the electroforming process cannot be ignored to fabricate reliable metal microdevices. Accurate measurement is the basis for studying the residual stress. Influenced by the topological feature size of micron scale in the metal microdevice, residual stress in it can hardly be measured by common methods. In this manuscript, a methodology is proposed to measure the residual stress in the metal microdevice using micro Raman spectroscopy (MRS). To estimate the residual stress in metal materials, micron sized β-SiC particles were mixed in the electroforming solution for codeposition. First, the calculated expression relating the Raman shifts to the induced biaxial stress for β-SiC was derived based on the theory of phonon deformation potentials and Hooke’s law. Corresponding micro electroforming experiments were performed and the residual stress in Ni–SiC composite layer was both measured by x-ray diffraction (XRD) and MRS methods. Then, the validity of the MRS measurements was verified by comparing with the residual stress measured by XRD method. The reliability of the MRS method was further validated by the statistical student’s t-test. The MRS measurements were found to have no systematic error in comparison with the XRD measurements, which confirm that the residual stresses measured by the MRS method are reliable. Besides that, the MRS method, by which the residual stress in a micro inertial switch was measured, has been confirmed to be a convincing experiment tool for estimating the residual stress in metal microdevice with micron order topological feature size.

  7. Measurement results obtained from air quality monitoring system

    Turzanski, P.K.; Beres, R. [Provincial Inspection of Environmental Protection, Cracow (Poland)


    An automatic system of air pollution monitoring operates in Cracow since 1991. The organization, assembling and start-up of the network is a result of joint efforts of the US Environmental Protection Agency and the Cracow environmental protection service. At present the automatic monitoring network is operated by the Provincial Inspection of Environmental Protection. There are in total seven stationary stations situated in Cracow to measure air pollution. These stations are supported continuously by one semi-mobile (transportable) station. It allows to modify periodically the area under investigation and therefore the 3-dimensional picture of creation and distribution of air pollutants within Cracow area could be more intelligible.

  8. Measurement of heart rate variability and stress evaluation by using microwave reflectometric vital signal sensing

    Nagae, Daisuke; Mase, Atsushi


    In this paper, we present two robust signal processing techniques for stress evaluation using a microwave reflectometric cardiopulmonary sensing instrument. These techniques enable the heart rate variability (HRV) to be recovered from measurements of body-surface dynamic motion, which is subsequently used for the stress evaluation. Specifically, two novel elements are introduced: one is a reconfiguration of the HRV from the cross-correlation function between a measurement signal and a template signal which is constructed by averaging periodic component over a measurement time. The other is a reconstruction of the HRV from the time variation of the heartbeat frequency; this is evaluated by a repetition of the maximum entropy method. These two signal processing techniques accomplish the reconstruction of the HRV, though they are completely different algorithms. For validations of our model, an experimental setup is presented and several sets of experimental data are analyzed using the two proposed signal processing techniques, which are subsequently used for the stress evaluation. The results presented herein are consistent with electrocardiogram data.


    D. A. Stepanenko


    Full Text Available Problems of design, fabrication and application of sensors for measurement of mechanical stresses in ultrasonic waveguide systems based on Villari effect and providing spatial resolution of measurements are considered. Results of experimental studies of spatial distribution of vibration parameters in waveguide systems for ultrasonic thrombolysis are presented. Technique of calibration and potential applications of the sensors are described.

  10. EMDR for Syrian refugees with posttraumatic stress disorder symptoms: results of a pilot randomized controlled trial

    Ceren Acarturk


    Full Text Available Background: The most common mental health problems among refugees are depression and posttraumatic stress disorder (PTSD. Eye movement desensitization and reprocessing (EMDR is an effective treatment for PTSD. However, no previous randomized controlled trial (RCT has been published on treating PTSD symptoms in a refugee camp population. Objective: Examining the effect of EMDR to reduce the PTSD and depression symptoms compared to a wait-list condition among Syrian refugees. Method: Twenty-nine adult participants with PTSD symptoms were randomly allocated to either EMDR sessions (n=15 or wait-list control (n=14. The main outcome measures were Impact of Event Scale-Revised (IES-R and Beck Depression Inventory (BDI-II at posttreatment and 4-week follow-up. Results: Analysis of covariance showed that the EMDR group had significantly lower trauma scores at posttreatment as compared with the wait-list group (d=1.78, 95% CI: 0.92–2.64. The EMDR group also had a lower depression score after treatment as compared with the wait-list group (d=1.14, 95% CI: 0.35–1.92. Conclusion: The pilot RCT indicated that EMDR may be effective in reducing PTSD and depression symptoms among Syrian refugees located in a camp. Larger RCTs to verify the (cost- effectiveness of EMDR in similar populations are needed.

  11. Development of methodology for measurements of residual stresses in welded joint based on displacement of points in a coordinated table

    Aníbal Veras Siqueira Filho


    Full Text Available Residual stresses in a welded joint of ASTM A131 grade AH32 steel was measured either by the X-ray diffraction or by displacements of referenced points measured on a coordinate measuring machine before and after heat treatment. For all tests, the welding was performed with Shielded Metal Arc Welding, vertical-up position, by a certified welder. After welding, some specimens were subjected to marking, made through small holes evenly spaced and mapped on a coordinate measuring machine. After labeling, the samples were subjected to heat treatment at temperatures nearby recrystallization. After heat treatment, the samples were subjected to new measurements by coordinate measuring machine to evaluate the displacements of the points produced by the recrystallization. In parallel, residual stress measurements were made by XRD for validation of this new methodology. The results obtained either by X-ray or by coordinate measuring machine showed a good correlation between the two measurement methodologies employed.

  12. Physiologic Measures of Animal Stress during Transitional States of Consciousness

    Robert E. Meyer


    Full Text Available Determination of the humaneness of methods used to produce unconsciousness in animals, whether for anesthesia, euthanasia, humane slaughter, or depopulation, relies on our ability to assess stress, pain, and consciousness within the contexts of method and application. Determining the subjective experience of animals during transitional states of consciousness, however, can be quite difficult; further, loss of consciousness with different agents or methods may occur at substantially different rates. Stress and distress may manifest behaviorally (e.g., overt escape behaviors, approach-avoidance preferences [aversion] or physiologically (e.g., movement, vocalization, changes in electroencephalographic activity, heart rate, sympathetic nervous system [SNS] activity, hypothalamic-pituitary axis [HPA] activity, such that a one-size-fits-all approach cannot be easily applied to evaluate methods or determine specific species applications. The purpose of this review is to discuss methods of evaluating stress in animals using physiologic methods, with emphasis on the transition between the conscious and unconscious states.

  13. Accuracy of soil stress measurements as affected by transducer dimensions and shape

    Lamandé, Mathieu; Keller, Thomas; Berisso, Feto Esimo


    Accurate measurements of soil stress are needed to evaluate the impact of traffic on soil properties and prevent soil compaction. Four types of transducer commonly used to measure vertical stress were calibrated in realistic traffic conditions in the field. The four transducer types differed in s...

  14. Instruction manual for the use of CSIR triaxial rock stress measuring equipment

    Coetzer, SJ


    Full Text Available This is an updated version of CSIR Report no ME 1763 entitled "Instruction manual for the use for the CSIR triaxial rock stress measuring equipment" by F A Vreede. The manual contains a detailed description of CSIR Triaxial rock stress measuring...

  15. Neutrino measurements from the Sun and Earth: Results from Borexino

    Bellini, G.; Caccianiga, B.; D’Angelo, D.; Giammarchi, M.; Lombardi, P.; Ludhova, L.; Meroni, E.; Miramonti, L.; Ranucci, G., E-mail:; Re, A. [Dipartimento di Fisica, Universitá degli Studi e INFN, 20133 Milano (Italy); Benziger, J. [Chemical Engineering Department, Princeton University, Princeton, New Jersey 08544 (United States); Bick, D.; Hagner, C.; Meyer, M. [Institut für Experimentalphysik, Universität Hamburg, 22761 Hamburg (Germany); Bonfini, G.; Cavalcante, P.; Gabriele, F.; Gazzana, S.; Ianni, Aldo; Laubenstein, M. [INFN Laboratori Nazionali del Gran Sasso, 67100 Assergi (Italy); and others


    Important neutrino results came recently from Borexino, a massive, calorimetric liquid scintillator detector installed at the underground Gran Sasso Laboratory. With its unprecedented radiopurity levels achieved in the core of the detection medium, it is the only experiment in operation able to study in real time solar neutrino interactions in the challenging sub-MeV energy region. The recently achieved breakthrough observation of the fundamental pp flux, the precise measurement of the {sup 7}Be solar neutrino flux, and the results concerning the pep, {sup 8}B and CNO fluxes, together with their physics implications, are described in this work. Moreover, the detector has also provided a clean detection of terrestrial neutrinos, from which they emerge as a new probe of the interior of the Earth.

  16. Recent Results of TMD Measurements from Jefferson Lab Hall A

    Jiang, Xiaodong [LANL


    This slide-show presents results on transverse momentum distributions. The presentation covers: target single-spin asymmetry (SSA) (in parity conserving interactions); • Results of JLab Hall A polarized {sup 3}He target TMD measurement; • Semi-­inclusive deep-inelastic scattering channels (E06-010); • Target single-spin asymmetry A{sub UT}, Collins and Sivers SSA on neutron; • Double-spin asymmetry A{sub LT}, extract TMD g{sub 1T} on neutron; • Inclusive channels SSA (E06-010, E05-015, E07-013) • Target SSA: inclusive {sup 3}He(e,e’) quasi-elastic scattering; • Target SSA: inclusive {sup 3}He(e,e’) deep inelastic-elastic scattering; • New SIDIS experiments planned in Hall-A for JLab-12 GeV.

  17. Hippocampal Structural Plasticity Accompanies the Resulting Contextual Fear Memory Following Stress and Fear Conditioning

    Giachero, Marcelo; Calfa, Gaston D.; Molina, Victor A.


    The present research investigated the resulting contextual fear memory and structural plasticity changes in the dorsal hippocampus (DH) following stress and fear conditioning. This combination enhanced fear retention and increased the number of total and mature dendritic spines in DH. Intra-basolateral amygdala (BLA) infusion of midazolam prior to…

  18. Predischarge stress test after myocardial infarction in the old stage : results and prognostic value

    P.M. Fioretti (Paolo); J.W. Deckers (Jaap); R.W. Brower (Ronald); M.L. Simoons (Maarten); J.A.J.M. Beelen; P.G. Hugenholtz (Paul)


    textabstractThe aim of this study was to evaluate the results of predischarge stress testing in the elderly, and to assess the prognostic value of the test during one-year follow-up. The database consisted of 48 patients older than 64 years of age and 109 patients 55-64 years of age, who survived ac

  19. Statistical evaluation of characteristic SDDLV-induced stress resultants to discriminate between undamaged and damaged elements

    Hansen, L. M.; Johansen, R. J.; Ulriksen, M. D.; Tcherniak, D.; Damkilde, L.


    The stochastic dynamic damage location vector (SDDLV) method utilizes the vectors from the kernel of a damaged-induced transfer function matrix change to localize damages in a structure. The kernel vectors associated with the lowest singular values are converted into static pseudo-loads and applied alternately to an undamaged reference model with known stiffness matrix, hereby, theoretically, yielding characteristic stress resultants approaching zero in the damaged elements. At present, the discrimination between potentially damaged elements and undamaged ones is typically conducted on the basis of modified characteristic stress resultants, which are compared to a pre-defined tolerance value, without any thorough statistical evaluation. In the present paper, it is tested whether three widely-used statistical pattern-recognition-based damage-detection methods can provide an effective statistical evaluation of the characteristic stress resultants, hence facilitating general discrimination between damaged and undamaged elements. The three detection methods in question enable outlier analysis on the basis of, respectively, Euclidian distance, Hotelling's T2 statistics, and Mahalanobis distance. The study of the applicability of these methods is based on experimentally obtained accelerations of a cantilevered residential-sized wind turbine blade subjected to an unmeasured multi-impulse load. The characteristic stress resultants are derived by applying the static pseudo-loads to a representative finite element (FE) model of the actual blade.

  20. Fan Noise Source Diagnostic Test: LDV Measured Flow Field Results

    Podboy, Gary C.; Krupar, Martin J.; Hughes, Christopher E.; Woodward, Richard P.


    Results are presented of an experiment conducted to investigate potential sources of noise in the flow developed by two 22-in. diameter turbofan models. The R4 and M5 rotors that were tested were designed to operate at nominal take-off speeds of 12,657 and 14,064 RPMC, respectively. Both fans were tested with a common set of swept stators installed downstream of the rotors. Detailed measurements of the flows generated by the two were made using a laser Doppler velocimeter system. The wake flows generated by the two rotors are illustrated through a series of contour plots. These show that the two wake flows are quite different, especially in the tip region. These data are used to explain some of the differences in the rotor/stator interaction noise generated by the two fan stages. In addition to these wake data, measurements were also made in the R4 rotor blade passages. These results illustrate the tip flow development within the blade passages, its migration downstream, and (at high rotor speeds) its merging with the blade wake of the adjacent (following) blade. Data also depict the variation of this tip flow with tip clearance. Data obtained within the rotor blade passages at high rotational speeds illustrate the variation of the mean shock position across the different blade passages.

  1. Effect of Escitalopram on Mental Stress-Induced Myocardial Ischemia: The Results of the REMIT Trial

    Jiang, Wei; Velazquez, Eric J.; Kuchibhatla, Maragatha; Samad, Zainab; Boyle, Stephen H.; Kuhn, Cynthia; Becker, Richard C.; Ortel, Thomas L.; Williams, Redford B.; Rogers, Joseph G.; O’Connor, Christopher


    Importance Mental-stress-induced myocardial ischemia (MSIMI) is an intermediate surrogate endpoint representing the pathophysiological link between psychosocial risk factors and adverse outcomes of coronary heart disease (CHD). However, pharmacological interventions aimed at reducing MSIMI have not been well studied. Objective To examine the effects of 6 weeks of escitalopram treatment vs. placebo on MSIMI and other psychological stress-related biophysiological and emotional parameters. Design, Setting, and Participants The REMIT study is a randomized, double-blind, placebo-controlled trial of patients with clinically stable CHD and laboratory MSIMI. Enrollment occurred from 7/24/2007–8/24/2011 at a tertiary medical center. Interventions Eligible participants were randomized 1:1 to receive escitalopram (dose began at 5 mg with titration to 20 mg/day in 3 weeks) or placebo over 6 weeks. Main Outcome Measure Occurrence of MSIMI, defined as (1) development or worsening of regional wall motion abnormality; (2) left ventricular ejection fraction reduction ≥8%; and/or (3) horizontal or downsloping ST-segment depression ≥1mm in ≥2 leads lasting for ≥3 consecutive beats during ≥1 of 3 mental tasks. Results 127 participants were randomized to escitalopram (n=64) or placebo (n=63); 112 (96.1%) completed endpoint assessments (n=56 in each arm). At the end of 6 weeks, more patients taking escitalopram (34.2% [95% CI, 25.4 to 43.0]) had absence of MSIMI during the 3 mental stressors compared with patients taking placebo (17.5% [95% CI, 10.4 to 24.5]) based on unadjusted multiple imputation model for intention-to-treat analysis. A significant difference favoring escitalopram was observed (OR=2.62 [95% CI, 1.06 to 6.44]). Rates of exercise-induced ischemia were slightly lower at 6 weeks in the escitalopram group (45.8% [95% CI, 36.6 to 55.0]) than in patients receiving placebo (52.5% [95% CI, 43.3 to 61.7]), compared with baseline escitalopram (49.2% [95% CI, 39.9 to

  2. Maternal obesity and malnourishment exacerbate perinatal oxidative stress resulting in diabetogenic programming in F1 offspring.

    Saad, M I; Abdelkhalek, T M; Haiba, M M; Saleh, M M; Hanafi, M Y; Tawfik, S H; Kamel, M A


    The effect of in-utero environment on fetal health and survival is long-lasting, and this is known as the fetal origin hypothesis. The oxidative stress state during gestation could play a pivotal role in fetal programming and development of diseases such as diabetes. In this study, we investigated the effect of intra-uterine obesity and malnutrition on oxidative stress markers in pancreatic and peripheral tissues of F1 offspring both prenatally and postnatally. Furthermore, the effect of postnatal diet on oxidative stress profile was evaluated. The results indicated that intra-uterine obesity and malnourishment significantly increased oxidative stress in F1 offspring. Moreover, the programming effect of obesity was more pronounced and protracted than malnutrition. The obesity-induced programming of offspring tissues was independent of high-caloric environment that the offspring endured; however, high-caloric diet potentiated its effect. In addition, pancreas and liver were the most affected tissues by fetal reprogramming both prenatally and postnatally. In conclusion, maternal obesity and malnutrition-induced oxidative stress could predispose offspring to insulin resistance and diabetes.

  3. Sensing of damage and substrate stress in concrete using electro-mechanical impedance measurements of bonded PZT patches

    Narayanan, Arun; Subramaniam, Kolluru V. L.


    The influence of stress and induced damage in concrete on the electro-mechanical (EM) impedance response of bonded PZT patches is evaluated for applied compressive loading. Full field displacements obtained from digital image correlation are used to evaluate the level of stress-induced damage in concrete. Stress in the substrate produces an imposed strain on the PZT. A change in the imposed strain produces a rightward frequency shift and an increase in the amplitude of the resonant peak in the EM conductance spectrum of the PZT. An increase in the substrate compliance produces a decrease in the resonant frequency and an increase in the amplitude of the resonant peak. Changes in the resonant peak in the conductance spectrum induced by increasing substrate stress are of a significant magnitude when compared with the changes induced by damage. In the early stages of damage associated with distributed microcracking, the counteracting influences of increasing level of damage and increasing stress on the resonant peak result in no shift in frequency for measurements under applied load. There is however an increase in the amplitude of the resonance peak. When the applied stress is removed, there is a net decrease in frequency resulting from damage in the form of distributed microcracks. Measures of changes in the resonant peak based on root mean square deviation (RMSD), do not show any observable change when measurements are performed under applied loading. There is a consistent increase in RMSD values and frequency shift with increasing damage when the applied stress is removed. The centroidal measure of the normalized frequency spectrum reflects changes in substrate stress. At higher applied stress levels, there is a nonlinear increase in damage, leading to localization and cracking. The influence of damage is dominant in this region and significant changes are obtained in the RMSD values in both loaded and unloaded conditions.

  4. Prilimary result of temperature distribution and associated thermal stress in crust in Tianshui, China

    LIU Yao-wei; GAO An-tai; SHI Jin; SU He-jun


    The heat flow in crust and the thermal stress generated by the flow play a very important role in earthquake occurrence. Different crustal structure has different effect on heat distribution and associated thermal stress. In all of typical seismogenic crustal structure models, including the bulge of Moho surface, the deep-large fault in the mid-lower crust, low-velocity and high-conductive layer in the middle crust, and the typical crustal structure in mid-upper crust, the thermal stress produced by deep heat disturbance may move up to the mid-upper crust. This leads to upper brittle part of crust break and hence, strong earthquakes. This result is constructive in enhancing our understanding of the role of deep heat flow in curst in development of earthquake and its generation, as well as the generation mechanism of the shallow flowing fluid.

  5. Effect of acute stresses on zebra fish (Danio rerio) metabolome measured by NMR-based metabolomics.

    Mushtaq, Mian Yahya; Marçal, Rosilene Moretti; Champagne, Danielle L; van der Kooy, Frank; Verpoorte, Robert; Choi, Young Hae


    We applied an acute stress model to zebra fish in order to measure the changes in the metabolome due to biological stress. This was done by submitting the fish to fifteen minutes of acute confinement (netting) stress, and then five minutes for the open field and light/dark field tests. A polar extract of the zebra fish was then subjected to (1)H nuclear magnetic spectroscopy. Multivariate data analysis of the spectra showed a clear separation associated to a wide range of metabolites between zebra fish that were submitted to open field and light/dark field tests. Alanine, taurine, adenosine, creatine, lactate, and histidine were high in zebra fish to which the light/dark field test was applied, regardless of stress, while acetate and isoleucine/lipids appeared to be higher in zebra fish exposed to the open field test. These results show that any change in the environment, even for a small period of time, has a noticeable physiological impact. This research provides an insight of how different mechanisms are activated under different environments to maintain the homeostasis of the body. It should also contribute to establish zebra fish as a model for metabolomics studies.

  6. The comparison of methods for measuring oxidative stress in zebrafish brains.

    Moussavi Nik, Seyyed Hani; Croft, Kevin; Mori, Trevor A; Lardelli, Michael


    The zebrafish is a versatile model organism with the potential to contribute to our understanding of the molecular pathological mechanisms underlying Alzheimer's disease (AD). An early characteristic of AD brain pathology is lipid peroxidation resulting from oxidative stress. However, changes in lipid peroxidation have not yet been assessed in zebrafish brains, and an earlier attempt to observe changes in F₂-isoprostane levels in the brains of zebrafish exposed to hypoxia was unsuccessful. In this article, we examine the utility of various assays of lipid peroxidation and more general assays of intracellular oxidative stress to detect the changes in oxidative stress in the brains of adult zebrafish exposed to hypoxia or explanted into a sodium azide solution for chemical mimicry of hypoxia. Levels of F₂-isoprostanes and F₄-neuroprostanes were low and variable in zebrafish brains such that statistically significant changes due to hypoxia or chemical mimicry of hypoxia could not be observed. However, measurement of lipid hydroperoxides did reveal significant changes in lipid peroxidation under these conditions, while analyses of catalase gene expression and an assay based on 2',7'-dicholorofluorescein oxidation also revealed changes in oxidative stress levels.

  7. Rolling Mill Work Roll Stress Analysis and Strain Measurement

    R. K. Jones


    This study of a rolling mill work roll failure consisted of (a) a review of related published materials, (b) measuring strain on the spindles with strain gages, (c) performing finite element analyses (FEA) modeling of the work roll thrust groove section (using the measured spindle loading), (d) fabricating and testing an physical model of the work roll, using the good end of a broken work roll, (e) recording motor voltage and current, and (f) processing, analyzing, and comparing the results. A methodical approach was taken to determine the causes of the failures. The actual loading to which the work rolls were subjected was determined, then these loads were used in a FEA of the thrust groove sections of three work roll designs: failed, current, and proposed. To verify the FEA results, a physical model was fabricated, built, and subjected to instrumented tests. The study offered the following recommendations: remove the undercut groove in the thrust groove section on future procurements; investigate possible methods of removing the transverse keyway; forego the larger drive train upgrades proposed by the mill manufacturer; continue frequent thrust groove inspections; require chemical and mechanical property certifications on all future procurements; and immediately scrap any work rolls that exhibit surface cracking.

  8. Measurement and study of the distributing law of in-situ stresses in rock mass at great depth


    To solve the technical cruxes of the conventional system in deep rock mass, an automatic testing system for hydraulic fracturing that includes a single tube for hydraulic loop, a pressure-relief valve, central-tubeless packers, and a multichannel real-time data acquisition system was used for in-situ stresses measurement at great depths (over 1000 m) in a coalfield in Juye of Northern China.The values and orientations of horizontal principal stresses were determined by the new system. The virgin stress field and its distributing law were decided by the linear regression from the logged 37 points in seven boreholes. Besides, the typical boreholes arranged in both the adjacent zone and far away zone of the faults were analyzed, respectively. The results show that a stress concentration phenomenon and a deflection in the orientation of the maximal horizontal stress exist in the adjacent zone of the faults, which further provides theoretical basis for design and optimization of mining.

  9. Alterations of CNS structure & function by charged particle radiation & resultant oxidative stress

    Nelson, Gregory; Chang, Polly; Favre, Cecile; Fike, John; Komarova, Natalia; Limoli, Charles; Mao, Xiao-Wen; Obenaus, Andre; Raber, Jacob; Spigelman, Igor; Soltesz, Ivan; Song, Sheng-Kwei; Stampanoni, Marco; Vlkolinsky, Roman; Wodarz, Dominik

    were complex and suggested continuous remodeling of the brain for up to 6 months. Thus we demonstrated a suite of CNS structural and functional changes after proton and iron ion exposure in the low dose regime. Based on these findings we will now test whether oxidative stress mediates the reactions of CNS to radiation exposure and what role radiation quality and dose rate play in the responses. We will use cultured neural precursor cells (mouse human) to detect changes in oxidative status and differentiation as functions of charged particle charge and velocity. These results will inform the selection of particles for many in vivo measurements that will compare wild type mice to a transgenic strain that over-expresses a human catalase gene (which inactivates hydrogen peroxide) in the mitochondrial compartment. This will explicitly test the role of reactive oxygen species in mediating the mechanisms underlying the CNS endpoints that we will measure. We will extend the electrophysiological measurements on individual nerves in hippocampal slices to characterize both inhibitory and excitatory synapses. Further, multi-electrode arrays will be used to follow correlated electrical activity in different hippocampal regions in order to understand network-level function as well as synaptic efficacy and plasticity. Controlled oxidative stress on irradiated samples will explore whether response mechanisms are shared. To link alterations in neurogenesis to performance we will explore behavioral changes mediated by the hippocampus simultaneously with measures of expression of the Arc gene in newly-born neurons. This will test whether decrements in performance correlate with loss of new cells and whether behavior properly stimulates functional integration of the new cells; the behavioral paradigm will be contextual fear conditioning. We will develop mathematical frameworks for CNS responses to radiation in order to inform risk estimates. Finally, we will couple a high

  10. Creation of a questionnaire to measure stress among nurses engaged in palliative care on general wards.

    Terakado, Ako; Watanabe, Takako


    This study was conducted to create a questionnaire that measures stress among nurses engaged in palliative care on general wards. Nurses with at least 3 years of experience involved in palliative care on a general ward in six facilities in Japan were the subjects from September 7 to October 4, 2004. A draft questionnaire on stress factors and conditions of stress in nurses engaged in end-of-life care was created, and question items and content meaning were revised to produce 32 question items, with a four-point Likert scale for the responses. Two pretests were conducted. Internal validity was investigated and resulted in 31 question items. Factor analysis using the principal factor method (Varimax rotation) was performed, and Cronbach's coefficient alpha was used to evaluate internal consistency and check reliability. The survey response rate was 94%, with a valid response rate of 98%. Analysis was conducted using responses from 269 participants, of whom 98.9% were female, with a mean age of 35.4 years. The mean length of experience as a nurse was 13.6 years, and the mean length of experience in cancer nursing was 8 years. Results of factor analysis produced eigenvalues of 5.260-1.558 and a cumulative proportion of 58.032%. After two items were deleted, six stress-related factors were identified; their alpha coefficients were 0.753 to 0.912, ensuring high reliability. The questionnaire developed had high internal validity and high reliability, and it can thus serve as a first stage in elucidating stress among nurses engaged in palliative care on general wards.

  11. Election results of Southwest ballot measures affecting healthcare

    Robbins RA


    Full Text Available No abstract available. Article truncated after 150 words. Earlier this week an article was posted listing Southwest ballot measures that affect healthcare. Below are the results obtained from various internet sources. States: Arizona: 1. Recreational marijuana. Proposition 205: Legalizes recreational marijuana use for people 21 and older. Opponents of the measure include the Arizona Health and Hospital Association and Insys Therapeutics, a company that makes a cannabis-based pain medication. Defeated: Yes 929,518 (48% No 1,011,836 (52%. California 1.Medi-Cal hospital fee program. Proposition 52: Requires the legislature to get voter approval to use fee revenue for purposes other than generating federal matching funds and funding enhanced Medicaid payments and grants for hospitals. The initiative, which was written by the California Hospital Association and is supported by most state lawmakers, would also make the program permanent, requiring a supermajority in the legislature to end it. Passed: Yes 5,950,642 (70% No 2,599,764 (30%. 2. Tobacco tax. Proposition 56: Increases the ...

  12. Effect of Acupressure on Non-stress Test (NST Results: A Randomized-Controlled Trial Study

    Masoume Pirhadi


    Full Text Available BackgroundPregnancy and delivery are among the most stressful events in women’s life . Breech presentation is defined as a fetus in a longitudinal lie with the buttocks or feet closest to the cervix. This occurs in 3-4% of all deliveries.The risk for perinatal mortality was 1 in 300 for planned breech deliveries.Some conventional non-surgical therapies for breech presentation are available. acupoint (BL67 stimulations are commonly used for the correction of breech presentation. The present study aimed to evaluate the effect of acupressure on fetal wellbeing test results.MethodThis study is a clinical trialthat was conducted in one group and the two-steps.Participantswere pregnant women (primigravida who were 35 to 18 years that refer to Shahid Beheshti hospital in Isfahan in 2013 to receive routine prenatal care.The 32 pregnant women (32-36 weeks were randomly selected.They were stimulated immediately after the first Non stress test and before the second test.The researchers’ evaluated and analyzed variables using SPSS software version 20.FindingsMean (SD age of the subjects was 24/7±2/8 and 93/8% of them was housekeeper. The frequency of reactive Non Stress Test (NST was same before and after stimulation. The mean time of the tests’ result was decreased after stimulation significantly ( p-value=0.048. ConclusionsAlthough fetal non-stress test result wasn’t influenced by acupressure but this intervention led to shorter testing time to achieve results. In other words, after the intervention, the time it takes to reach a reactive fetal non-stress test is about 2/7 minutes less than the time without intervention.

  13. Measuring spiral arm torques results for M100

    Gnedin, O Y; Frei, Z; Gnedin, Oleg Y; Goodman, Jeremy; Frei, Zsolt


    Spiral arms, if they are massive, exert gravitational torques that transport angular momentum radially within galactic disks. These torques depend not on the pattern speed or permanence of the arms but only on the nonaxisymmetric mass distribution. Hence the torques can be measured from photometry. We demonstrate this using gri CCD data for M100 (NGC 4321). Since we find consistency among the three bands, we believe that dust and young stars in the arms do not seriously bias our results. If the present epoch is representative, the timescale for redistribution of angular momentum in M100 is 5-10 Gyr, the main uncertainty being the mass-to-light ratio of the disk.

  14. Responses of Early Lactating Ewes to Cold Stress Exposure Preliminary Results

    Dinu Gavojdian


    Full Text Available The aim of this study was to measure cold stress of ewes during post lambing period. The trial was undertaken at theExperimental Farm of Banat’s University of Agricultural Sciences and Veterinary Medicine Timisoara, duringFebruary 2012. Six secundiparous Turcana breed ewes were housed in two collective pens of 3.5 m x 2 m each, withdeep straw bedding, in shed where the average temperature was of -1.2°C. Cortisol levels from milk samples weredetermined as indicators of cold stress. Samples were collected at 14 hours after lambing, and at 7, 14 and 21 daysfollowing parturition. At 14 hours after lambing, mean cortisol levels were 7.78±0.47 μg/dl, and decreased asfollows: 5.08±0.72 μg/dl in the 7th of the trial, 2.75±0.50 μg/dl in day 14 and 1.61±0.43 μg/dl in day 21 of theobservations. Differences were significant between the 7 day sampling intervals (p≤0.01 during the first 14 daysafter lambing, while non-significant differences (p≥0.05 have been found between the 14 and 21 days samplings. Ithas been concluded that cortisol levels in milk samples could prove an indicator of sheep adrenal-cortex activity thatmay be applied to measure cold stress in lactating ewes.

  15. Laser deposition of YBaCuO thin films: stress measurements and microstructure investigations

    Gaboriaud, R. J.; Pailloux, F.


    Superconducting thin films of YBaCuO have been deposited by laser ablation at 750°C on MgO (001) single crystals. X-ray pole figures indicate a high crystalline quality of c-axis oriented films. A four-circle X-ray goniometer has been used for the measurements of the internal stress in the films by means of the fundamental metric tensor method generally used in the field of continuum mechanics. Microstructural investigation has been done by HRTEM on plan-view samples in order to study the film-substrate epitaxy relations from the observation of the moiré pattern brought about by the superimposition of both YBaCuO and MgO lattices (9% misfit). The results are discussed in terms of crystallographic accommodation and stress relaxation between the film and the substrate.

  16. Bias stress instability in organic transistors investigated by ac admittance measurements

    Di Girolamo, F. V.; Barra, M.; Capello, V.; Oronzio, M.; Romano, C.; Cassinese, A.


    In this paper, the bias stress effect (BSE) in organic field-effect transistors has been analyzed by an alternative experimental approach based on ac admittance (Y=G+jωC) measurements. conductance (C) and capacitance (G) curves have been recorded as a function of frequency at different times of the bias stress experiments and simultaneously fitted through a transmission line circuit, able to separately model the conducting properties of the channel and contact regions. The determination of the time behavior of the model fitting parameters is assumed as the starting point for a quantitative analysis of the BSE occurrence. This experimental procedure clarifies that both channel resistance (Rch) and contact resistance (Rc) are largely affected by the BSE, while the channel capacitance (Cch), related to the charge accumulation sheet, and the contact capacitance (Cc) result almost unchanged.

  17. Perceived stress, recurrent pain, and aggregate salivary cortisol measures in mid-adolescent girls and boys.

    Lindfors, Petra; Folkesson Hellstadius, Lisa; Östberg, Viveca


    Measures of perceived stress have been criticized for theoretical inconsistency. However, the validated pressure activation stress scale has been suggested as a theoretically sound alternative. But it is unclear how pressure and activation stress relate to objective and subjective measures including commonly used aggregate cortisol measures and health complaints respectively. Specifically, this study aimed at investigating how pressure and activation stress were related to aggregate salivary cortisol measures and recurrent pain in mid-adolescent girls and boys. Mid-adolescents (119 girls and 56 boys) provided self-reports in questionnaires on activation and pressure stress and recurrent pain (headache, stomach ache, neck/shoulder and back pain). Additionally, adolescents sampled saliva during an ordinary school day: (1) immediately at awakening; (2) 30 minutes after waking up; (3) 60 minutes after waking up, and (4) at 8 p.m. These samples were analyzed for cortisol. Hierarchical regressions showed no statistically significant associations between activation and pressure stress and cortisol, neither for girls nor for boys. However, activation and pressure stress were significantly associated with recurrent pain but only for girls. The findings may relate to subjective and objective measures reflecting distinct aspects of stress-related functioning. However, the study participants included mid-adolescents whose bodily systems are flexible and still relatively unaffected by the strain of their daily stress perceptions. To conclude, the non-significant relationships between activation and pressure stress and commonly used aggregate measures of cortisol adds to the understanding of how perceived stress may relate to physiological functioning in the daily life of adolescents when using such aggregate measures.

  18. Does uranium exposure induce oxidative stress and genotoxicity in the teleostean Danio rerio? first experimental results

    Barillet, S.; Devaux, A.; Simon, O.; Buet, A.; Pradines, C. [CEA Cadarache (DEI/SECRE/LRE), Laboratory of Radioecology and Ecotoxicology, Institute for Radioprotection and Nuclear Safety, 13 - Saint-Paul-lez-Durance (France)


    Within the Envirhom research program, key advances have been obtained in uranium bioaccumulation and underlying mechanisms understanding in various biological models at the individual level. However, considering different scales of biological effects (from early to delayed ones, from low to high level of organization) is crucial to provide ecologically relevant indicators. Organisms counteract stress induced by pollutant exposure through a wide range of physiological responses being both dose and time dependent. Effects at higher hierarchical levels are always preceded by early changes in biological processes, from subtle biochemical disturbances to impaired physiological functions, increased susceptibility to other stresses, reduced life-span Within this global context, preliminary experiments were carried out on adult zebra fish (Danio rerio), to assess early changes after short-term uranium exposure. Among the subsequent primary subcellular damages oxidative stress and genotoxicity (characterizing both chemo-toxicity and radiotoxicity) are relevant endpoints, thus requiring the knowledge of dose-effects relationships as a first operational approach to provide useful tool in predicting possible effects of U exposure. Zebra fish has been selected due to its small size (facilitating its maintenance) and its extended use in eco-toxicological studies. Moreover, its short life-cycle will allow to carry out chronic exposure experiments (along the whole life-cycle). Four uranium concentrations (0, 20, 100 and 500{mu}g.L{sup -1}) and five sampling times (0, 0.5, 1, 5 and 10 days) were selected. Catalase, glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were measured as oxidative stress bio-markers. DNA damage level was assessed in zebra fish erythrocytes using the comet assay. Uranium bioaccumulation was concurrently studied to understand observed bio-marker responses. Further experiments, dedicated to the assessment of the impact of chronic uranium

  19. The response of an equatorial ocean to simple wind stress patterns. I - Model formulation and analytic results. II - Numerical results

    Cane, M. A.


    A time-dependent, primitive equation, beta plane model that is two-dimensional in the horizontal has been developed to model wind-driven equatorial ocean circulation. A simple vertical structure consisting of two layers above the thermocline with the same constant density permits a steady-state undercurrent in the model. An analytical study of the linear dynamics of the model suggests that the addition of inertial effects is needed to simulate the undercurrent properly. Also, both linear and nonlinear dynamics of the model are investigated numerically. Such nonlinear response to wind stress as a strong eastward equatorial undercurrent and an intense eastward 'countercurrent' at three deg N are noted in the numerical results.

  20. Stress release model and proxy measures of earthquake size. Application to Italian seismogenic sources

    Varini, Elisa; Rotondi, Renata; Basili, Roberto; Barba, Salvatore


    This study presents a series of self-correcting models that are obtained by integrating information about seismicity and fault sources in Italy. Four versions of the stress release model are analyzed, in which the evolution of the system over time is represented by the level of strain, moment, seismic energy, or energy scaled by the moment. We carry out the analysis on a regional basis by subdividing the study area into eight tectonically coherent regions. In each region, we reconstruct the seismic history and statistically evaluate the completeness of the resulting seismic catalog. Following the Bayesian paradigm, we apply Markov chain Monte Carlo methods to obtain parameter estimates and a measure of their uncertainty expressed by the simulated posterior distribution. The comparison of the four models through the Bayes factor and an information criterion provides evidence (to different degrees depending on the region) in favor of the stress release model based on the energy and the scaled energy. Therefore, among the quantities considered, this turns out to be the measure of the size of an earthquake to use in stress release models. At any instant, the time to the next event turns out to follow a Gompertz distribution, with a shape parameter that depends on time through the value of the conditional intensity at that instant. In light of this result, the issue of forecasting is tackled through both retrospective and prospective approaches. Retrospectively, the forecasting procedure is carried out on the occurrence times of the events recorded in each region, to determine whether the stress release model reproduces the observations used in the estimation procedure. Prospectively, the estimates of the time to the next event are compared with the dates of the earthquakes that occurred after the end of the learning catalog, in the 2003-2012 decade.

  1. A database for storing the results of material radiopurity measurements

    Loach, J. C.; Cooley, J.; Cox, G. A.; Li, Z.; Nguyen, K. D.; Poon, A. W. P.


    Searches for rare nuclear processes, such as neutrinoless double beta-decay and the interactions of WIMP dark matter, are motivating experiments with ever-decreasing levels of radioactive backgrounds. These background reductions are achieved using various techniques, but amongst the most important is minimizing radioactive contamination in the materials from which the experiment is constructed. To this end there have been decades of advances in material sourcing, manufacture and certification, during which researchers have accumulated many thousands of measurements of material radiopurity. Some of these assays are described in publications, others are in databases, but many are still communicated informally. Until this work, there has been no standard format for encoding assay results and no effective, central location for storing them. The aim of this work is to address these long-standing problems by creating a concise and flexible material assay data format and powerful software application to manipulate it. A public installation of this software, available at, is the largest database of assay results ever compiled and is intended as a long-term repository for the community's data.

  2. Methods of Measuring Stress Relaxation in Composite Tape Springs


    additional analysis done in SOLIDWORKS . For the first method of analysis, PolyWorks is used to cut out the unnecessary portions of the raw scan data. Then...each tape spring is exported as a ‘.stl’ file. This file is imported as a surface into a SOLIDWORKS part file. The SOLIDWORKS parts are combined into...analyzed using MATLAB, PolyWorks, and SOLIDWORKS . These data provide a greater insight into the stress relaxation of tape springs when deformed

  3. Minimization and Mitigation of Wire EDM Cutting Errors in the Application of the Contour Method of Residual Stress Measurement

    Ahmad, Bilal; Fitzpatrick, Michael E.


    The contour method of residual stress measurement relies on the careful application of wire electro-discharge machining (WEDM) for the cutting stage. Changes in material removal rates during the cut lead to errors in the final calculated values of residual stress. In this study, WEDM cutting parameters have been explored to identify the optimum conditions for contour method residual stress measurements. The influence of machine parameters on the surface roughness and cutting artifacts in the contour cut is discussed. It has been identified that the critical parameter in improving the surface finish is the spark pulse duration. A typical cutting artifact and its impact on measured stress values have been identified and demonstrated for a contour cut in a welded marine steel. A procedure is presented to correct contour displacement data from the influence of WEDM cutting artifacts, and is demonstrated on the correction of a measured weld residual stress. The corrected contour method improved the residual stress magnitude up to 150 MPa. The corrected contour method results were validated by X-ray diffraction, incremental center hole drilling, and neutron diffraction.

  4. Results of Sexbierum Wind Farm: single wake measurements

    Cleijne, J.W.


    In the framework of the JOULE-0064 'Full-scale Measurements in Wind Turbine Arrays' in the period between June-November 1992 measurements have been performed in the Sexbierum Wind Farm. The aim of the measurements is to provide data for the validation of wake and wind farm models, which are being de

  5. Workshop on industrial application of neutron diffraction. Stress measurement by neutron diffraction

    Minakawa, N; Morii, Y; Oyama, Y


    This workshop was planned to make use of the neutron from the reactor and the pulse neutron source JSNS for the industrial world. Especially, this workshop focused on the stress measurement by the neutron diffraction and it was held on the Tokai JAERI from October 15 to 16, 2001. The participant total was 93 and 40 participated from the industrial world. The introduction of the residual stress development of measurement technique by the neutron diffraction method and a research of the measurement of the residual stress such as the nuclear reactor material, the ordinary structure material, the composite material, the quenching steel, the high strength material were presented and discussed in this workshop. Moreover, it was introduced for the industrial world that an internal stress measurement is important for development of new product or an improvement of a manufacturing process. The question from the industrial world about which can be measured the product form, the size, the measurement precision, the reso...

  6. Results from laboratory and field testing of nitrate measuring spectrophotometers

    Snazelle, Teri T.


    Five ultraviolet (UV) spectrophotometer nitrate analyzers were evaluated by the U.S. Geological Survey (USGS) Hydrologic Instrumentation Facility (HIF) during a two-phase evaluation. In Phase I, the TriOS ProPs (10-millimeter (mm) path length), Hach NITRATAX plus sc (5-mm path length), Satlantic Submersible UV Nitrate Analyzer (SUNA, 10-mm path length), and S::CAN Spectro::lyser (5-mm path length) were evaluated in the HIF Water-Quality Servicing Laboratory to determine the validity of the manufacturer's technical specifications for accuracy, limit of linearity (LOL), drift, and range of operating temperature. Accuracy specifications were met in the TriOS, Hach, and SUNA. The stock calibration of the S::CAN required two offset adjustments before the analyzer met the manufacturer's accuracy specification. Instrument drift was observed only in the S::CAN and was the result of leaching from the optical path insert seals. All tested models, except for the Hach, met their specified LOL in the laboratory testing. The Hach's range was found to be approximately 18 milligrams nitrogen per liter (mg-N/L) and not the manufacturer-specified 25 mg-N/L. Measurements by all of the tested analyzers showed signs of hysteresis in the operating temperature tests. Only the SUNA measurements demonstrated excessive noise and instability in temperatures above 20 degrees Celsius (°C). The SUNA analyzer was returned to the manufacturer at the completion of the Phase II field deployment evaluation for repair and recalibration, and the performance of the sensor improved significantly.


    亚敏; 戴福隆; 谢惠民; 吕坚


    Hole-drilling method is one of the most convenient methods for engineering residual ment data, hole-drilling technique can be used to solve non-uniform residual stress problems, both (MIIHD) for non-uniform residual stress measurement is introduced. Three dimensional finite element model is constructed by ABAQUS to obtain the coefficients for the residual stress calculation.An experimental system including real-time measurement, automatic data processing and residual stresses calculation is established. Two applications for non-uniform in-depth residual stress of surface nanocrystalline material and non-uniform in-plane residual stress of friction stir welding are presented.Experimental results show that MIIHD is effective for both non-uniform in-depth and in-plane residual stress measurements.

  8. Measurements of thermal residual stresses in SiC/Ti-15-3 composites

    Bobet, J.-L.; Masuda, C. [National Research Inst. for Metals, Tsukuba, Ibaraki (Japan)


    Residual stresses present in an as received and thermally cycled SCS-6/Ti-15-3 metal matrix composite (MMC) have been approached via X-ray diffraction (sin{sup 2}{psi}) experiments. Determination of stress profiles have been achieved by successive removal of the matrix from the composite surface by electropolishing. Axial and hoop stresses in the matrix were tensile (higher on the surface) and those measured in the fiber were compressive (about -500 to -600 MPa). A stress gradient normal to the surface of the composite was found. Measurement of residual stress levels in the composite subjected to thermal cycling from 400degC to 800degC in an inert atmosphere or in vacuum revealed a huge stress relaxation after only 200 cycles. (author)

  9. Prediction and measurement of relieved residual stress by the cryogenic heat treatment for Al6061 alloy: mechanical properties and microstructure

    Ko, Dae Hoon; Ko, Dae Cheol; Kim, Byung Min [Pusan National University, Busan (Korea, Republic of); Lim, Hak Jin; Lee, Jung Min [Poongsan Co., Gyungju (Korea, Republic of)


    The purpose of this study is to predict the residual stress resulting from the cryogenic heat treatment (CHT) which affects the mechanical properties and microstructure for Al6061 alloy. The CHT is very effective method to reduce the residual stress by quenching media such as liquid nitrogen, boiling water and steam. In this study, experimental T6 and CHT are carried out to measure the temperature of Al parts and to determine the convective heat transfer coefficient. This coefficient is used to predict the residual stress during FE-simulation. In order to consider the relaxation of residual stress during artificial ageing, the Zener-Wert-Avrami function with elasto-plastic nonlinear analysis is used in this study. The predicted residual stress is compared with the measured one by X-ray diffraction (XRD) and is found to be in good agreement with results of the FE-simulation. Further, after T6 and CHT, the electrical conductivity and hardness of the Al6061 alloy are measured to estimate the mechanical properties and its microstructure such as precipitates is observed by Transmission electron microscopy (TEM). Also, the creation of precipitates during T6 and CHT are verified by XRD with component analysis. It is found that CHT affects the residual stress, mechanical properties, and precipitation of the Al 6061 alloy.

  10. Instantaneous strain measurements during high-temperature stress cycling of a dispersion-strengthened niobium alloy

    Farkas, D.M.; Mishra, R.S.; Mukherjee, A.K. [Univ. of California, Davis, CA (United States). Dept. of Chemical Engineering and Materials Science


    Experimental results obtained from stress cycling tests performed during high-temperature creep of a dispersion strengthened niobium alloy indicate that the instantaneous strain following the stress change decreases with accumulated strain. The true work-hardening rate was shown to be a small fraction of the elastic modulus which remained fairly constant throughout the strain history. The instantaneous strain change from a stress addition was typically greater than the strain from the corresponding stress reduction. This effect is quite pronounced for small stress changes and diminishes as the magnitude of the stress change increases. This implies that the mobility of dislocations is impeded in the reverse direction unless the magnitude of stress reduction exceeds the value of the internal stress.

  11. Neutron scattering instruments for residual stress/strain measurements at KUR

    Ono, Masayoshi [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.


    A Kyoto University Reactor project research finished on March, 1997 is a first trial in Japan. In this research, some residual stress measurement in accompany with thermal and processing deformation history of various superconductive composite wires and so on were conducted to obtain a lot of research results. At TOF system, simultaneous measurement of the direction dependent collective texture using a multi point detector was useful, and at PSD system the strain measurement in a region under 10{sup -4} became possible to conduct. In addition, it is intending now to establish high performance instruments such as a two-stage type disc chopper at the TOF system and a high resolution vent type Si monocrystal monochromator at the PSD system. In particular, it is expected a the TOF system that a direction dependent collective texture and a stress distribution state in various kinds of functional materials can be measured simultaneously and without destruction. The mechanical property research of the metallic materials using low speed neutron scattering method is now a big interest in and out of Japan. This research contains a lot of contents coinciding to the industrial fields in an application research field of nuclear basic research and is expected in future to powerfully promote international cooperative research and to deeply recognize its usefulness and importance. (G.K.)

  12. Measuring stress before and during pregnancy: a review of population-based studies of obstetric outcomes.

    Witt, Whitney P; Litzelman, Kristin; Cheng, Erika R; Wakeel, Fathima; Barker, Emily S


    Mounting evidence from clinic and convenience samples suggests that stress is an important predictor of adverse obstetric outcomes. Using a proposed theoretical framework, this review identified and synthesized the population-based literature on the measurement of stress prior to and during pregnancy in relation to obstetric outcomes. Population-based, peer-reviewed empirical articles that examined stress prior to or during pregnancy in relation to obstetric outcomes were identified in the PubMed and PsycInfo databases. Articles were evaluated to determine the domain(s) of stress (environmental, psychological, and/or biological), period(s) of stress (preconception and/or pregnancy), and strength of the association between stress and obstetric outcomes. Thirteen studies were evaluated. The identified studies were all conducted in developed countries. The majority of studies examined stress only during pregnancy (n = 10); three examined stress during both the preconception and pregnancy periods (n = 3). Most studies examined the environmental domain (e.g. life events) only (n = 9), two studies examined the psychological domain only, and two studies examined both. No study incorporated a biological measure of stress. Environmental stressors before and during pregnancy were associated with worse obstetric outcomes, although some conflicting findings exist. Few population-based studies have examined stress before or during pregnancy in relation to obstetric outcomes. Although considerable variation exists in the measurement of stress across studies, environmental stress increased the risk for poor obstetric outcomes. Additional work using a lifecourse approach is needed to fill the existing gaps in the literature and to develop a more comprehensive understanding of the mechanisms by which stress impacts obstetric outcomes.

  13. Compassion satisfaction, compassion fatigue, anxiety, depression and stress in registered nurses in Australia: study 1 results.

    Hegney, Desley G; Craigie, Mark; Hemsworth, David; Osseiran-Moisson, Rebecca; Aoun, Samar; Francis, Karen; Drury, Vicki


    To explore compassion fatigue and compassion satisfaction with the potential contributing factors of anxiety, depression and stress. To date, no studies have connected the quality of work-life with other contributing and co-existing factors such as depression, anxiety and stress. A self-report exploratory cross sectional survey of 132 nurses working in a tertiary hospital. The reflective assessment risk profile model provides an excellent framework for examining the relationships between the professional quality of work factors and contributing factors within the established risk profiles. The results show a definite pattern of risk progression for the six factors examined for each risk profile. Additionally, burnout and secondary traumatic stress were significantly related to higher anxiety and depression levels. Higher anxiety levels were correlated with nurses who were younger, worked full-time and without a postgraduate qualification. Twenty percent had elevated levels of compassion fatigue: 7.6% having a very distressed profile. At-risk nurses' stress and depression scores were significantly higher than nurses with higher compassion satisfaction scores. The employed nurse workforce would benefit from a psychosocial capacity building intervention that reduces a nurse's risk profile, thus enhancing retention. © 2013 John Wiley & Sons Ltd.

  14. Is plant endophyte-mediated defensive mutualism the result of oxidative stress protection?

    White, James F; Torres, Mónica S


    In this review, we discuss the biology and beneficial effects of plant endophytes on host plants. The current explanation of endophyte protection (defensive mutualism) of host plants is based on the secondary metabolites (alkaloids) with antiherbivore properties produced by the symbiotic association between host plant and endophytes. We propose an alternative explanation of the mechanism of host protection through enhanced stress tolerance to oxidative stress. Several studies have demonstrated the production of different compounds (phenolics) with antioxidant capacity in endophyte-infected plants. Endophytes may also produce mannitol, other carbohydrates and small molecules (proline) with antioxidant capacity. We suggest that enhanced antioxidant production by symbiotic plants may be the result of the production of reactive oxygen species (ROS) by endophytes. In turn, symbiotic plants are protected from oxidative stress produced by plant diseases, droughts, heavy metals and other oxidative stressors by the production of antioxidants. We also discuss the lichen symbiosis and evaluate whether management of ROS also plays a role in this defensive mutualism. Future experiments are needed to evaluate the hypothesis that antioxidants are responsible for enhanced stress tolerance in endophyte-infected plants.

  15. Stress Measurement in Coal Seam Ahead of Longwall Face - Case Study

    Kukutsch, R. (Radovan); P. Koníček; Waclawik, P. (Petr); Ptáček, J.; Staš, L. (Lubomír); M. Vavro; Hastíková, A. (Alice)


    Stress measurement and stress monitoring is an important task in mining geomechanics, because knowledge of the stress - strain state in a rock mass is the determining factor for the proper planning of roadway support and for the correct design of underground mining. This strategy is useful for ensuring mining safety, because increasing depth causes several issues, especially in areas with rockbur st hazard, when roadways are loaded by the pressure ahead...

  16. Hyperhomocysteinemia is a result, rather than a cause, of depression under chronic stress.

    Shen Chengfeng

    Full Text Available BACKGROUND: Although the accumulation of homocysteine (Hcy has been implicated in the pathogenesis of depression, whether Hcy is directly involved and acts as the primary cause of depressive symptoms remains unclear. The present study was designed to clarify whether increased Hcy plays an important role in stress-induced depression. RESULTS: We employed the chronic unpredictable mild stress model (CUMS of depression for 8 weeks to observe changes in the plasma Hcy level in the development of depression. The results showed that Wistar rats exposed to a series of mild, unpredictable stressors for 4 weeks displayed depression-like symptoms such as anhedonia (decreased sucrose preferences and a decreased 5-Hydroxy Tryptophan (5-HT concentration in the hippocampus. At the end of 8 weeks, the plasma Hcy level increased in the CUMS rats. The anti-depressant sertraline could decrease the plasma Hcy level and improve the depression-like symptoms in the CUMS rats. RhBHMT, an Hcy metabolic enzyme, could decrease the plasma Hcy level significantly, although it could not improve the depressive symptoms in the CUMS rats. CONCLUSIONS: The results obtained from the experiments did not support the hypothesis that the increased Hcy concentration mediated the provocation of depression in CUMS rats, and the findings suggested that the increased Hcy concentration in the plasma might be the result of stress-induced depression.

  17. Mechanical Stress Results in Immediate Accumulation of Glucosinolates in Fresh-Cut Cabbage

    Tomaž Požrl


    Full Text Available The intensity of mechanical stress and the temperature significantly affect the levels of individual and total glucosinolates in shredded white cabbage (cv. Galaxy. Mild processing (shredding to 2 mm thickness at 8°C resulted in the accumulation of glucosinolates (40% increase in comparison with unshredded cabbage, which was already seen 5 min after the mechanical stress. Severe processing (shredding to 0.5 mm thickness at 20°C, however, resulted in an initial 50% decrease in glucosinolates. The glucosinolates accumulated in all of the cabbage samples 30 min from processing, resulting in higher levels than in unshredded cabbage, except for the severe processing at 20°C where the increase was not sufficient to compensate for the initial loss. Glucobrassicin and neoglucobrassicin were the major glucosinolates identified in the cabbage samples. Mechanical stress resulted in an increase in the relative proportion of glucobrassicin and in a decrease in neoglucobrassicin.

  18. Reynolds and Maxwell stress measurements in the reversed field pinch experiment Extrap-T2R

    Vianello, N.; Antoni, V.; Spada, E.; Spolaore, M.; Serianni, G.; Cavazzana, R.; Bergsåker, H.; Cecconello, M.; Drake, J. R.


    The complete Reynolds stress (RS) has been measured in the edge region of the Extrap-T2R reversed field pinch experiment. The RS exhibits a strong gradient in the region where a high E × B shear takes place. Experimental results show this gradient to be almost entirely due to the electrostatic contribution. This has been interpreted as experimental evidence of flow generation via turbulence mechanism. The scales involved in flow generation are deduced from the frequency decomposition of RS tensor. They are found related to magnetohydrodynamic activity but are different with respect to the scales responsible for turbulent transport.

  19. Wearable Biomedical Measurement Systems for Assessment of Mental Stress of Combatants in Real Time

    Fernando Seoane


    Full Text Available The Spanish Ministry of Defense, through its Future Combatant program, has sought to develop technology aids with the aim of extending combatants’ operational capabilities. Within this framework the ATREC project funded by the “Coincidente” program aims at analyzing diverse biometrics to assess by real time monitoring the stress levels of combatants. This project combines multidisciplinary disciplines and fields, including wearable instrumentation, textile technology, signal processing, pattern recognition and psychological analysis of the obtained information. In this work the ATREC project is described, including the different execution phases, the wearable biomedical measurement systems, the experimental setup, the biomedical signal analysis and speech processing performed. The preliminary results obtained from the data analysis collected during the first phase of the project are presented, indicating the good classification performance exhibited when using features obtained from electrocardiographic recordings and electrical bioimpedance measurements from the thorax. These results suggest that cardiac and respiration activity offer better biomarkers for assessment of stress than speech, galvanic skin response or skin temperature when recorded with wearable biomedical measurement systems.

  20. Study on in-situ stress measurement around coastal marginal land in Fujian

    LI Hong; AN Qi-mei; XIE Fu-ren


    The in-situ hydraulic fracturing stress measurements have been carried out around the coastal marginal land in Fujian Province. And the characteristics of magnitude, direction and distribution of tectonic stress have been obtained.Based on the observed stress data, the characteristics and activities of fault zones are analyzed and studied in the paper according to the Coulomb friction criteria. ① The maximum horizontal principal compressive stress is in the NW-WNW direction from the north to the south along the coastline verge, which is parallel to the strike of the NW-trending fault zone, consistent with the direction of principal compressive stress obtained from geological structure and across-fault deformation data, and different from that reflected by focal mechanism solution by about 20°. ② The horizontal principal stress increases with depth, the relation among three stresses is SH>Sv>Sh or SH≈Sv>Sh, and the stress state is liable to normal fault and strike-slip fault activities. ③ According to Coulomb friction criteria and taking the friction strength μ as 0.6~1.0 for analysis, the stress state reaching or exceeding the threshold for normal-fault frictional sliding near the fault implies that the current tectonic activity in the measuring area is mainly normal faulting. ④ The force source of current tectonic stress field comes mainly from the westward and northwestward horizontal extrusions from the Pacific and Philippine Plates respectively to the Eurasian Plate.

  1. Measurement of ability emotional intelligence: results for two new tests.

    Austin, Elizabeth J


    Emotional intelligence (EI) has attracted considerable interest amongst both individual differences researchers and those in other areas of psychology who are interested in how EI relates to criteria such as well-being and career success. Both trait (self-report) and ability EI measures have been developed; the focus of this paper is on ability EI. The associations of two new ability EI tests with psychometric intelligence, emotion perception, and the Mayer-Salovey-Caruso EI test (MSCEIT) were examined. The new EI tests were the Situational Test of Emotion Management (STEM) and the Situational Test of Emotional Understanding (STEU). Only the STEU and the MSCEIT Understanding Emotions branch were significantly correlated with psychometric intelligence, suggesting that only understanding emotions can be regarded as a candidate new intelligence component. These understanding emotions tests were also positively correlated with emotion perception tests, and STEM and STEU scores were positively correlated with MSCEIT total score and most branch scores. Neither the STEM nor the STEU were significantly correlated with trait EI tests, confirming the distinctness of trait and ability EI. Taking the present results as a starting-point, approaches to the development of new ability EI tests and models of EI are suggested.

  2. Tunka-Rex: Status and results of the first measurements

    Kostunin, D., E-mail: [Institut für Kernphysik, Karlsruhe Institute of Technology (KIT) (Germany); Budnev, N.M.; Gress, O.A. [Institute of Applied Physics ISU, Irkutsk (Russian Federation); Haungs, A.; Hiller, R.; Huege, T. [Institut für Kernphysik, Karlsruhe Institute of Technology (KIT) (Germany); Kazarina, Y. [Institute of Applied Physics ISU, Irkutsk (Russian Federation); Kleifges, M. [Institut für Prozessdatenverarbeitung und Elektronik, Karlsruhe Institute of Technology (KIT) (Germany); Konstantinov, A. [Skobeltsyn Institute of Nuclear Physics MSU, Moscow (Russian Federation); Konstantinov, E.N. [Institute of Applied Physics ISU, Irkutsk (Russian Federation); Korosteleva, E.E. [Skobeltsyn Institute of Nuclear Physics MSU, Moscow (Russian Federation); Krömer, O. [Institut für Prozessdatenverarbeitung und Elektronik, Karlsruhe Institute of Technology (KIT) (Germany); Kuzmichev, L.A. [Skobeltsyn Institute of Nuclear Physics MSU, Moscow (Russian Federation); Mirgazov, R.R.; Pankov, L. [Institute of Applied Physics ISU, Irkutsk (Russian Federation); Prosin, V.V. [Skobeltsyn Institute of Nuclear Physics MSU, Moscow (Russian Federation); Rubtsov, G.I. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Rühle, C. [Institut für Prozessdatenverarbeitung und Elektronik, Karlsruhe Institute of Technology (KIT) (Germany); Schröder, F.G. [Institut für Kernphysik, Karlsruhe Institute of Technology (KIT) (Germany); Svetnitsky, E. [Institute of Applied Physics ISU, Irkutsk (Russian Federation); and others


    Tunka-Rex is the new radio extension of Tunka-133 located in Siberia close to Lake Baikal. The latter is a photomultiplier array registering air-Cherenkov light from air showers induced by cosmic-ray particles with initial energies of approximately 10{sup 16}–10{sup 18}eV. Tunka-Rex extends this detector with 25 antennas spread over an area of 1 km{sup 2}. It is triggered externally by Tunka-133, and detects the radio emission of the same air showers. The combination of an air-Cherenkov and a radio detector provides a facility for hybrid measurements and cross-calibration between the two techniques. The main goal of Tunka-Rex is to determine the precision of the reconstruction of air-shower parameters using the radio detection technique. It started operation in autumn 2012. We present the overall concept of Tunka-Rex, the current status of the array and first analysis results.

  3. Propagation of Nonlinear Waves in Waveguides and Application to Nondestructive Stress Measurement

    Nucera, Claudio

    , where the classical physics of nonlinear wave propagation assumes finite strains, the case at hand of constrained thermal expansion is, instead, characterized by infinitesimal (ideally zero) strains. Hand-in-hand with the theoretical analyses, a comprehensive program of experimental testing has been conducted at UCSD's Large-Scale Rail NT Test-bed, a unique 70-ft track with controlled temperature excursions constructed at UCSD's Powell Laboratories with government and industry funding. A prototype has been constructed for wayside determination of the rail NT based on the measurement of wave nonlinearities. The experimental results obtained with the prototype in the Large-Scale Test-bed are extremely encouraging, showing an accuracy of only a few degrees for the determination of the rail NT. If confirmed in the field, this result could revolutionize the way CWR are maintained to prevent rail buckling with respect to the thermal stress management problem.

  4. Diagonalization and representation results for nonpositive sesquilinear form measures

    Hytönen, Tuomas; Pellonpää, Juha-Pekka; Ylinen, Kari


    We study decompositions of operator measures and more general sesquilinear form measures E into linear combinations of positive parts, and their diagonal vector expansions. The underlying philosophy is to represent E as a trace class valued measure of bounded variation on a new Hilbert space related to E. The choice of the auxiliary Hilbert space fixes a unique decomposition with certain properties, but this choice itself is not canonical. We present relations to Naimark type dilations and direct integrals.

  5. Glass-modified stress waves for adhesion measurement of ultra thin films for device applications

    Gupta, Vijay; Kireev, Vassili; Tian, Jun; Yoshida, Hiroshi; Akahoshi, Haruo


    Laser-generated stress wave profiles with rarefaction shocks (almost zero post-peak decay times) have been uncovered in different types of glasses and presented in this communication. The rise time of the pulses was found to increase with their amplitude, with values reaching as high as 50 ns. This is in contrast to measurements in other brittle crystalline solids where pulses with rise times of 1 -2 ns and post-peak decay times of 16 -20 ns were recorded. The formation of rarefaction shock is attributed to the increased compressibility of glasses with increasing pressures. This was demonstrated using a one-dimensional nonlinear elastic wave propagation model in which the wave speed was taken as a function of particle velocity. The technological importance of these pulses in measuring the tensile strength of very thin film interfaces is demonstrated by using a previously developed laser spallation experiment in which a laser-generated compressive stress pulse in the substrate reflects into a tensile wave from the free surface of the film and pries off its interface at a threshold amplitude. Because of the rarefaction shock, glass-modified waves allow generation of substantially higher interfacial tensile stress amplitudes compared with those with finite post-peak decay profiles. Thus, for the first time, tensile strengths of very strong and ultra thin film interfaces can be measured. Results presented here indicate that interfaces of 185-nm-thick films, and with strengths as high as 2.7 GPa, can be measured. Thus, an important advance has been made that should allow material optimization of ultra thin layer systems that may form the basis of future MEMS-based microelectronic, mechanical and clinical devices.

  6. Measurement of the residual stress in hot rolled strip using strain gauge method

    Kumar, Lokendra; Majumdar, Shrabani; Sahu, Raj Kumar


    Measurement of the surface residual stress in a flat hot rolled steel strip using strain gauge method is considered in this paper. Residual stresses arise in the flat strips when the shear cut and laser cut is applied. Bending, twisting, central buckled and edge waviness is the common defects occur during the cutting and uncoiling process. These defects arise due to the non-uniform elastic-plastic deformation, phase transformation occurring during cooling and coiling-uncoiling process. The residual stress analysis is very important because with early detection it is possible to prevent an object from failure. The goal of this paper is to measure the surface residual stress in flat hot rolled strip using strain gauge method. The residual stress was measured in the head and tail end of hot rolled strip considering as a critical part of the strip.

  7. Research on Measurements for Temperature and Stress of Pistons in Internal Combustion Engine

    DONG Xiao-rui; TAN Jian-song


    In both numerical simulation and experimental research for the piston of internal combustion engine, the verification foundations are always insufficient. The reason is the measurements for its transient temperature and stress under actual operation conditions are very difficult. A multi-channel measurement-storage technology is used in the engine bench experiment to measure the piston temperature and stress in real time. The temperature and stress changes in the engine operation process are obtained. They provide reliable instructive criteria for numerical analysis and experiment of the piston working state.

  8. Residual stress measurements with barkhausen noise in power plant creep failure analysis

    Karvonen, I. [CoMoTest Oy, Maentsaelae (Finland)] Suominen, L. [Stresstech Oy, Jyvaeskylae (Finland)


    Continuously developing power and process industry needs predictive maintenance inspection methods in order to prevent failures with correctly timed and properly specified measures. Materials` monitoring has traditionally been non-destructive inspection to detect growing cracks or other deficiencies. Recently, after the development of portable stress measurement systems, some advances has been reached. Based on stress anomalies due to creep, fatigue or corrosion, new applications have been found in the use of Barkhausen noise inspection. When the Barkhausen noise findings have been simultaneously confirmed with other stress measuring methods, a wider acceptance of the application of the method can be proposed. (orig.) 7 refs.

  9. Laser sheet scattered light method for industrial measurement of thickness residual stress distribution in flat tempered glass

    Castellini, P.; Stroppa, L.; Paone, N.


    The paper presents the laser sheet scattered light technique, a fast optical non contact method for measuring internal stress distribution over a cross section of flat glass specimens, designed for closed loop control of glass tempering furnaces. The technique is an evolution of the scattered light method for flat glass residual stress analysis and allows a full thickness stress profile to be measured with a single shot acquisition across a glass plate without any contact. A linearly polarized laser sheet, shaped into a thin plane of parallel light beams, enters orthogonally to the side of the flat glass illuminating its full thickness. Light sheet is orthogonal to the glass surface and travels parallel to it. Stress induced birefringence through the glass affects light polarization, thus scattered light intensity detected at 90° with respect to the polarization of the incident light appears spatially modulated in intensity. A camera aligned orthogonal to the laser light polarization collects an image of fringes whose shape is digitally analyzed to measure the thickness stress state. The paper describes the development of this technique by recalling the scattered light method, then describing its automation by scanning a collimated beam across the glass thickness and finally by showing that the scan method can be substituted by the light sheet method. Light sheet method provides a full field non contact stress measurement across the glass thickness, thus allowing for a fast inspection method, suitable for industrial use. Flat glass items for industrial use have bevelled edges; this does not allow measurements close to glass surface. To solve this limit, experimental data are extrapolated by a symmetrical polynomial fitting and imposing a zero integral to the stress profile. Results on surface stress measured by the laser sheet scattered method are in agreement with those of the automated light scattered method and show a fair agreement with measurement by an

  10. Measuring permeability, Young's modulus, and stress relaxation by the beam-bending technique

    Vichit-Vadakan, Wilasa

    Recent interest in the permeability of cement paste, mortars, and concrete lies in the need to gain further understanding of mechanisms affecting the durability of these materials. Conventional techniques for measuring permeability are cumbersome and often take days to complete just one measurement. This thesis proposes a new technique for measuring the permeability. The advantage of this technique is that the results are obtained in a few minutes to a few hours; moreover, there is no problem with leaks or need for high pressures. The method is particularly well suited for examining the changes in permeability and viscoelastic properties of young cement paste samples. When a saturated rod of a porous material is instantaneously deflected under three-point bending, two types of relaxation processes occur simultaneously: hydrodynamic relaxation, caused by the flow of liquid in the porous body to restore ambient pressure, and viscoelastic relaxation of the solid network. By measuring the decrease in the force required to sustain a constant deflection, it is possible to obtain the permeability and Young's modulus from the hydrodynamic relaxation function, in addition to the stress relaxation function of the sample. The exact viscoelastic solution is developed and the total relaxation is shown to be very closely approximated as the product of the hydrodynamic and stress relaxation functions. The analytical results are verified on porous VycorRTM glass saturated in various solvents, including normal alcohols, water, and glycerol. The results show excellent agreement with the theory. Consistent with observations of previous workers, the permeability is found to be influenced by the size of the solvent molecule; by assuming that the pore surfaces are covered with a monolayer of immobile solvent, the observed variation can be explained. The evolution of the permeability, Young's modulus, and stress relaxation function are reported for Type III Portland cement paste with

  11. Isolated systems with wind power. Results of measurements in Egypt

    Bindner, Henrik W.; Saleh, L.; Hafiez, S.A.;


    The objective of the measurements were to characterise different types of consumer loads in order to be able to construct load patterns to be used in feasibility studies where the available data often will be incomplete, not available or not existing. Measurements have been carried out at five di...

  12. Instruction manual for the use of the CSIR triaxial rock stress measuring equipment

    Vreede, F. A.


    A guide is presented for users of an instrument designed to measure the state of stress at any one point in a rock mass. The overscoring technique used to determine the absolute stress is described as well as equipment components. A computer program for processing the data is discussed and the equations on which the program is based are given.

  13. Evaluation of Various Pulse-Decay Laboratory Permeability Measurement Techniques for Highly Stressed Coals

    Feng, Ruimin; Harpalani, Satya; Pandey, Rohit


    The transient technique for laboratory permeability measurement, proposed by Brace et al. (J Geophys Res 73:2225-2236, 1968) and widely used for conventional gas reservoir rocks, is the preferred method when testing low-permeability rocks in the laboratory. However, Brace et al.'s solution leads to considerable errors since it does not take into account compressive storage and sorption effect when applied to sorptive rocks, such as, coals and shales. To verify the applicability of this solution when used to characterize fluid flow behavior of coal, an in-depth investigation of permeability evolution for flow of helium and methane depletion was conducted for San Juan coals using the pressure pulse-decay method under best replicated in situ conditions. Three permeability solutions, Brace et al.'s (1968), Dicker and Smits's (International meeting on petroleum engineering, Society of Petroleum Engineers, 1988) and Cui et al.'s (Geofluids 9:208-223, 2009), were utilized to establish the permeability trends. Both helium and methane permeability results exhibited very small difference between the Brace et al.'s solution and Dicker and Smits's solution, indicating that the effect of compressive storage is negligible. However, methane permeability enhancement at low pressures due to coal matrix shrinkage resulting from gas desorption can be significant and this was observed in pressure response plots and the estimated permeability values using Cui et al.'s solution only. Therefore, it is recommended that Cui et al.'s solution be employed to correctly include the sorption effect when testing coal permeability using the transient technique. A series of experiments were also carried out to establish the stress-dependent permeability trend under constant effective stress condition, and then quantify the sole contribution of the sorption effect on permeability variation. By comparison with the laboratory data obtained under in situ stress/strain condition, it was verified that

  14. Inversion of calcite twin data for stress (2) : EBSD as a tool for data measurements

    Parlangeau, Camille; Lacombe, Olivier; Brisset, Francois; Kohler, Eric; Daniel, Jean-Marc; Schueller, Sylvie


    and its coordinates entered in a file later used to pilot automatically the EBSD spot. This new procedure is applied on sections from natural samples; the EBSD data are converted and restored into the geographical framework and analyzed using the improved Etchecopar stress inversion technique. The results are compared to the results obtained from classical, optically-based measurements of the same sections using the Universal-stage. The advantages and limitations of this approach are discussed.

  15. Analysis of faults stability with dynamic phenomena in the mine based on slide criterion and in-situ stress measurement

    SONG Wei-hua; WANG Yu-feng; WANG Xin-hua


    For the study on the relationship between the dynamic phenomena in the mining such as mine earthquakes,outburst and faults slide,firstly,double shear friction experiments of sandstone were made,and its slide criterion was suggested considering the viewing of engineering.Secondly,in order to study the stability of underground rock and zone of tectonic stress field,based on the analysis on distribution characteristic of initial rock stress measurements,the geology structural model was built and tectonic stress field was made a back-analysis by applying finite element method.The calculating results fit with the analysis result of earthquakes mechanism and the distribution characteristic of the measurements.The high stress regional centers station locates discontinuous zone of I level faults and is corresponding to underground earthquakes scene.From then it is certain that tectonic stress is the major origin and necessary condition of mine earthquakes.The instability slide of the faults is the main manifest and the mining activity is the leading factor.Beipiao fault has a dominate effect on other sub faults and tectonic stress area and is dynamical fountain of dynamic phenomena in the Beipiao Mines.

  16. Analysis of faults stability with dynamic phenomena in the mine based on slide criterion and in-situ stress measurement

    SONG Wei-hua; WANG Yu-feng; WANG Xin-hua


    For the study on the relationshfp between the dynamic phenomena in the min-ing such as mine earthquakes, outburst and faults slide, firstly, double shear friction ex-periments of sandstone were made, and its slide criterion was suggested considering the viewing of engineering. Secondly, in order to study the stability of underground rock and zone of tectonic stress field, based on the analysis on distribution characteristic of initial rock stress measurements, the geology structural model was built and tectonic stress field was made a back-analysis by applying finite element method. The calculating results fit with the analysis result of earthquakes mechanism and the distribution characteristic of the measurements. The high stress regional centers station locates discontinuous zone of I level faults and is corresponding to underground earthquakes scene. From then it is cer-tain that tectonic stress is the major origin and necessary condition of mine earthquakes. The instability slide of the faults is the main manifest and the mining activity is the leading factor. Beipiao fault has a dominate effect on other sub faults and tectonic stress area and is dynamical fountain of dynamic phenomena in the Beipiao Mines.

  17. Bond strength and stress measurements in thermal barrier coatings

    Gell, M.; Jordan, E. [Univ. of Connecticut, Storrs, CT (United States)


    Thermal barrier coatings have been used extensively in aircraft gas turbines for more than 15 years to insulate combustors and turbine vanes from the hot gas stream. Plasma sprayed thermal barrier coatings (TBCs) provide metal temperature reductions as much as 300{degrees}F, with improvements in durability of two times or more being achieved. The introduction of TBCs deposited by electron beam physical vapor deposition (EB-PVD) processes in the last five years has provided a major improvement in durability and also enabled TBCs to be applied to turbine blades for improved engine performance. To meet the aggressive Advanced Turbine Systems goals for efficiency, durability and the environment, it will be necessary to employ thermal barrier coatings on turbine airfoils and other hot section components. For The successful application of TBCs to ATS engines with 2600{degrees}F turbine inlet temperatures and required component lives 10 times greater than those for aircraft gas turbine engines, it is necessary to develop quantitative assessment techniques for TBC coating integrity with time and cycles in ATS engines. Thermal barrier coatings in production today consist of a metallic bond coat, such as an MCrAlY overlay coating or a platinum aluminide (Pt-Al) diffusion coating. During heat treatment, both these coatings form a thin, tightly adherent alumina (Al{sub 2}O{sub 3}) film. Failure of TBC coatings in engine service occurs by spallation of the ceramic coating at or near the bond coat to alumina or the alumina to zirconia bonds. Thus, it is the initial strength of these bonds and the stresses at the bond plane, and their changes with engine exposure, that determines coating durability. The purpose of this program is to provide, for the first time, a quantitative assessment of TBC bond strength and bond plane stresses as a function of engine time and cycles.

  18. Genetic influence on blood pressure measured in the office, under laboratory stress and during real life

    Wang, Xiaoling; Ding, Xiuhua; Su, Shaoyong; Harshfield, Gregory; Treiber, Frank; Snieder, Harold

    To determine to what extent the genetic influences on blood pressure (BP) measured in the office, under psychologically stressful conditions in the laboratory and during real life are different from each other...

  19. A novel concept of measuring mass flow rates using flow induced stresses

    P I Jagad; B P Puranik; A W Date


    Measurement of mass flow rate is important for automatic control of the mass flow rate in many industries such as semiconductor manufacturing and chemical industry (for supply of catalyst to a reaction). In the present work, a new concept for direct measurement of mass flow rates which does not depend on the volumetric flow rate measurement and obviates the need for the knowledge of density is proposed from the measurement of the flow induced stresses in a substrate. The concept is formulated by establishing the relationship between the mass flow rate and the stress in the substrate. To this end, the flow field and the stress field in the substrate are evaluated simultaneously using a numerical procedure and the necessary correlations are derived. A least squares based procedure is used to derive the mass flow rate from the correlations as a function of the stress in the substrate.

  20. Measurement of stress-strain behaviour of human hair fibres using optical techniques.

    Lee, J; Kwon, H J


    Many studies have presented stress-strain relationship of human hair, but most of them have been based on an engineering stress-strain curve, which is not a true representation of stress-strain behaviour. In this study, a more accurate 'true' stress-strain curve of human hair was determined by applying optical techniques to the images of the hair deformed under tension. This was achieved by applying digital image cross-correlation (DIC) to 10× magnified images of hair fibres taken under increasing tension to estimate the strain increments. True strain was calculated by summation of the strain increments according to the theoretical definition of 'true' strain. The variation in diameter with the increase in longitudinal elongation was also measured from the 40× magnified images to estimate the Poisson's ratio and true stress. By combining the true strain and the true stress, a true stress-strain curve could be determined, which demonstrated much higher stress values than the conventional engineering stress-strain curve at the same degree of deformation. Four regions were identified in the true stress-strain relationship and empirical constitutive equations were proposed for each region. Theoretical analysis on the necking condition using the constitutive equations provided the insight into the failure mechanism of human hair. This analysis indicated that local thinning caused by necking does not occur in the hair fibres, but, rather, relatively uniform deformation takes place until final failure (fracture) eventually occurs.

  1. A new sensor for stress measurement based on blood flow fluctuations

    Fine, I.; Kaminsky, A. V.; Shenkman, L.


    It is widely recognized that effective stress management could have a dramatic impact on health care and preventive medicine. In order to meet this need, efficient and seamless sensing and analytic tools for the non-invasive stress monitoring during daily life are required. The existing sensors still do not meet the needs in terms of specificity and robustness. We utilized a miniaturized dynamic light scattering sensor (mDLS) which is specially adjusted to measure skin blood flow fluctuations and provides multi- parametric capabilities. Based on the measured dynamic light scattering signal from the red blood cells flowing in skin, a new concept of hemodynamic indexes (HI) and oscillatory hemodynamic indexes (OHI) have been developed. This approach was utilized for stress level assessment for a few usecase scenario. The new stress index was generated through the HI and OHI parameters. In order to validate this new non-invasive stress index, a group of 19 healthy volunteers was studied by measuring the mDLS sensor located on the wrist. Mental stress was induced by using the cognitive dissonance test of Stroop. We found that OHIs indexes have high sensitivity to the mental stress response for most of the tested subjects. In addition, we examined the capability of using this new stress index for the individual monitoring of the diurnal stress level. We found that the new stress index exhibits similar trends as reported for to the well-known diurnal behavior of cortisol levels. Finally, we demonstrated that this new marker provides good sensitivity and specificity to the stress response to sound and musical emotional arousal.

  2. Systematic Review of Uit Parameters on Residual Stresses of Sensitized AA5456 and Field Based Residual Stress Measurements for Predicting and Mitigating Stress Corrosion Cracking


    significant amount of grinding and other sorts of damage marks that may have influenced the measurements. These measurements will be repeated on non...Mech. Eng., Naval Postgraduate School, Monterey, CA, 2012. 107 [24] M. Pourbaix, Atlas of Electrochemical Equilibria, Houston, TX: National...Journal of Electrochemical Science and Technology, vol. 129, no. 12, pp. 2660–2665, Dec. 1982. [26] H. L. Logan, "Film rupture mechanism of stress

  3. Compassion satisfaction, compassion fatigue, anxiety, depression and stress in registered nurses in Australia: phase 2 results.

    Drury, Vicki; Craigie, Mark; Francis, Karen; Aoun, Samar; Hegney, Desley G


    This is the first two-phase Australian study to explore the factors impacting upon compassion satisfaction, compassion fatigue, anxiety, depression and stress and to describe the strategies nurses use to build compassion satisfaction into their working lives. Compassion fatigue has been found to impact on job satisfaction, the quality of patient care and retention within nursing. This study provides new knowledge on the influences of anxiety, stress and depression and how they relate to compassion satisfaction and compassion fatigue. In Phase 2 of the study, 10 nurses from Phase 1 of the study participated in individual interviews and a focus group. A semi-structured interview schedule guided the conversations with the participants. Data analysis resulted in seven main themes: social networks and support;infrastructure and support; environment and lifestyle; learning; leadership; stress; and suggestions to build psychological wellness in nurses. Findings suggest that a nurse’s capacity to cope is enhanced through strong social and collegial support, infrastructure that supports the provision of quality nursing care and positive affirmation. These concepts are strongly linked to personal resilience. for nursing management These findings support the need for management to develop appropriate interventions to build resilience in nurses.

  4. Fatigue Failure Results for Multi-Axial versus Uniaxial Stress Screen Vibration Testing

    Wayne E. Whiteman


    Full Text Available To date, the failure potential and prediction between simultaneous multi-axial versus sequentially applied uniaxial vibration stress screen testing has been the subject of great debate. In most applications, current vibration tests are done by sequentially applying uniaxial excitation to the test specimen along three orthogonal axes. The most common standards for testing military equipment are published in MIL-STD-810F and NAVMAT P-9492. Previous research had shown that uniaxial testing may be unrealistic and inadequate. This current research effort is a continuing effort to systematically investigate the differences between fatigue damage mechanisms and the effects of uniaxial versus tri-axial testing. This includes assessing the ability of the tri-axial method in predicting the formation of damage mechanisms, specifically looking at the effects of stress or fatigue failure. Multi-axial testing achieves the synergistic effect of exciting all modes simultaneously and induces a more realistic vibration stress loading condition. As such, it better approximates real-world operating conditions. This paper provides the latest results on the differences between multi-axial and uniaxial testing of a simple notched cantilever beam.

  5. Instrumented sphere method for measuring thermal pressure in fluids and isotropic stresses and reaction kinetics in thermosetting resins

    Merzlyakov, Mikhail; Meng, Yan; Simon, Sindee L.; McKenna, Gregory B.


    A novel technique is described for measuring thermal pressure in fluids and for measuring isotropic stress development and reaction kinetics in thermosetting resins during cure and thermal cycling. The method uses a 12.7-mm-diam sealed stainless steel spherical pressure vessel to impose three-dimensional isotropic constraints. The vessel is instrumented with strain gauges and thermocouples. Both isotropic stresses and reaction kinetics during cure at cure temperatures as high as 300 °C can be measured. In addition, measurement of the isotropic stress as a function of temperature yields the thermal pressure coefficient in both the glassy and rubbery (or liquid) states. Experimental results are presented for sucrose benzoate, a pressure-transmitting oil di-2-ethylhexylsebacate and an epoxy resin. The method provides reproducible estimates for the thermal pressure coefficient and the stresses are highly isotropic. A suggestion for improved versions of the device is: thicker walled vessels can be used to increase the upper stress limit (currently at 30 MPa). Also if a lower temperature range is to be studied, then aluminum can be used as a vessel material. Since epoxy resins have better adhesion to aluminum than to stainless steel, there may be an advantage to this.

  6. Nondestructive and Localized Measurements of Stress-Strain Curves and Fracture Toughness of Ferritic Steels at Various Temperatures Using Innovative Stress-Strain Microprobe Technology. Final Report for Period 8/13/1996--06/16/1999

    Fahmy M. Haggag


    The results presented in this report demonstrate the capabilities of Advanced Technology Corporation's patented Portable/In Situ Stress-Strain Microprobe (TM) (SSM) System and its Automated Ball Indentation (ABI) test techniques to nondestructively measure the yield strength, the stress-strain curve, and the fracture toughness of ferritic steel samples and components in a reliable and accurate manner.

  7. Urban traffic noise assessment by combining measurement and model results

    Eerden, F.J.M. van der; Graafland, F.; Wessels, P.W.; Basten, T.G.H.


    A model based monitoring system is applied on a local scale in an urban area to obtain a better understanding of the traffic noise situation. The system consists of a scalable sensor network and an engineering model. A better understanding is needed to take appropriate and cost efficient measures,

  8. Measurement of Perceived Stress Among Pregnant Women: A Comparison of Two Different Instruments.

    Solivan, Amber E; Xiong, Xu; Harville, Emily W; Buekens, Pierre


    Assess the amount of agreement between the classification of stress from the Perceived Stress Scale (PSS) and the Assessment of Stress portion of the Prenatal Psychosocial Profile (PPP) among pregnant women. A secondary data analysis on a cross-sectional study of 301 pregnant women from the New Orleans and Baton Rouge areas who were exposed to Hurricane Katrina was conducted. Women with complete data (219) were analyzed. Women scoring in the third tertile of each instrument were compared. The kappa statistic was used to assess agreement between instruments. Additional comparisons were made with three instruments that measure other important psychosocial constructs that could be related to stress: the Edinburgh Depression Scale (EDS) and the Assessments of Support (partner and other support) and Self-Esteem from the PPP. No significant difference was found between the two tests. The PSS and the PPP were both statistically significantly correlated to each other (ρ = 0.71, p < 0.01). Thirty-five women were classified discordantly resulting in a Kappa Coefficient of 0.61 (95% CI 0.50-0.72, p < 0.01). No significant differences were found between these two instruments in correlation with the EDS (PPP, r = 0.76; PSS, r = 0.72; p < 0.01 for each), partner support (PPP, r = -0.47; PSS r = -0.46; p < 0.01 for each), other support (PPP, r = -0.31; PSS r = -0.32; p < 0.01 for each) and self-esteem (PPP, r = -0.41; PSS, r = -0.52; p < 0.01 for each), respectively. Given the similarities between the PSS and PPP, researchers are encouraged to choose and administer one instrument to participants, or to use the instruments in combination as an external reliability check.

  9. 26 CFR 801.6 - Business results measures.


    ... audit. Records of tax enforcement results do not include tax enforcement results of individual cases... IRS personnel provided accurate tax law and account information. (3) Other work units. The quality... data that does not contain information regarding the tax enforcement result reached in any case...

  10. Swept frequency eddy current (SFEC) measurements of Inconel 718 as a function of microstructure and residual stress

    Chandrasekar, Ramya

    The goal of this thesis was to determine the dependency of swept frequency eddy current (SFEC) measurements on the microstructure of the Ni-based alloy, Inconel 718 as a function of heat treatment and shot peening. This involved extensive characterization of the sample using SEM and TEM coupled with measurements and analysis of the eddy current response of the various sample conditions using SFEC data. Specific objectives included determining the eddy current response at varying depths within the sample, and this was accomplished by taking SFEC measurements in frequencies ranging from 100 kHz to 50 MHz. Conductivity profile fitting of the resulting SFEC signals was obtained by considering influencing factors (such as surface damage). The problems associated with surface roughness and near surface damage produced by shot peening were overcome by using an inversion model. Differences in signal were seen as a result of precipitation produced by heat treatment and by residual stresses induced due to the shot peening. Hardness of the material, which is related both to precipitation and shot peening, was seen to correlate with the measured SFEC signal. Surface stress measurement was carried out using XRD giving stress in the near surface regions, but not included in the calculations due to shallow depth information provided by the technique compared to SFEC. By comparing theoretical SFEC signal computed using the microstructural values (precipitate fraction) and experimental SFEC data, dependency of the SFEC signals on microstructure and residual stress was obtained.

  11. Mindfulness training and stress reactivity in substance abuse: results from a randomized, controlled stage I pilot study.

    Brewer, Judson A; Sinha, Rajita; Chen, Justin A; Michalsen, Ravenna N; Babuscio, Theresa A; Nich, Charla; Grier, Aleesha; Bergquist, Keri L; Reis, Deidre L; Potenza, Marc N; Carroll, Kathleen M; Rounsaville, Bruce J


    Stress is important in substance use disorders (SUDs). Mindfulness training (MT) has shown promise for stress-related maladies. No studies have compared MT to empirically validated treatments for SUDs. The goals of this study were to assess MT compared to cognitive behavioral therapy (CBT) in substance use and treatment acceptability, and specificity of MT compared to CBT in targeting stress reactivity. Thirty-six individuals with alcohol and/or cocaine use disorders were randomly assigned to receive group MT or CBT in an outpatient setting. Drug use was assessed weekly. After treatment, responses to personalized stress provocation were measured. Fourteen individuals completed treatment. There were no differences in treatment satisfaction or drug use between groups. The laboratory paradigm suggested reduced psychological and physiological indices of stress during provocation in MT compared to CBT. This pilot study provides evidence of the feasibility of MT in treating SUDs and suggests that MT may be efficacious in targeting stress.

  12. Caring for the Caregivers: Results of an Extended, Five-component Stress-reduction Intervention for Hospital Staff.

    Sallon, Sarah; Katz-Eisner, Deborah; Yaffe, Hila; Bdolah-Abram, Tali


    The health-related consequences of stress in hospital workers and associated costs of absenteeism and high turnover have increased the need for programs targeting stress in this population. "Caring for the Caregivers," a multimodal approach to stress-reduction designed to address the multidimensional nature of stress in hospital staff, integrates five components: cognitive, somatic, dynamic, emotive and hands-on, in a flexible eight-month format. Significant improvements were demonstrated for 97 participants compared to 67 controls in pre-post scores for the Maslach Burnout Inventory, Job-Related Tension Index, Perceived Stress Scale, Productivity Scale, General Health Questionnaire, Positive and Negative Affect Schedule, and Visual Analogue Scales of 12 stress-associated symptoms. Together with significant reduction in upper respiratory infections and family doctor visits, these results suggest that providing hospital staff with multiple techniques addressing commonly encountered work stressors impacts positively on health and well-being and significantly reduces stress and burnout in this population.

  13. Vehicular-to-vehicular channel characterization and measurement results

    CAMPUZANO CANDEL, ANDRÉS JOSÉ; FERNÁNDEZ GONZÁLEZ, HERMAN ANTONIO; BALAGUER ANDRÉS, DAVID; Vila Jiménez, Antonio; Bernardo Clemente, Bernardo; Rodrigo Peñarrocha, Vicent Miquel; Reig, Juan; Valero-Nogueira, Alejandro; Rubio Arjona, Lorenzo


    Vehicular-to-Vehicular (V2V) communications are receiving considerable attention due to the introduction of the intelligent transportation system (ITS) concept. To design, evaluate and optimize ITS applications oriented to vehicular safety based on wireless systems, the knowledge of the propagation channel is vital, in particular the path loss. From a narrowband V2V channel measurements campaign carried out in a suburban area of the city of Valencia (Spain), this paper...

  14. Wall shear stress measurement in blade end-wall corner region

    Bhargava, R.; Raj, R.; Boldman, D. R.


    The magnitude and the direction of wall shear stress and surface pressure in the blade end-wall corner region were investigated. The measurements were obtained on a specially designed Preston tube, the tip of which could be concentrically rotated about its axis of rotation at the measurement location. The magnitude of wall shear stress in the vicinity of the corner was observed to increase significantly (170 percent) compared to its far-upstream value; the increase was consistently higher on the blade surface compared to the value on the plate surface of the blade end-wall corner. On both surfaces in the blade end-wall corner, the variation of the wall shear stress direction was found to be more predominant in the vicinity of the blade leading-edge location. The trend of the measured wall shear stress direction showed good agreement with the limiting streamline directions obtained from the flow visualization studies.


    Henningsen, Poul; Arentoft, Mogens; Lagergren, Jonas;


    A load transducer has been developed to measure the contact forces in the deformation zone during rolling. The transducer consists of a strain gauge equipped insert, embedded in the surface of the roll. The length of the insert exceeds the contact length between material and roll. By analyzing...

  16. In Situ Measurement of Voltage-Induced Stress in Conducting Polymers with Redox-Active Dopants.

    Sen, Sujat; Kim, Sung Yeol; Palmore, Lia R; Jin, Shenghua; Jadhav, Nitin; Chason, Eric; Palmore, G Tayhas R


    Minimization of stress-induced mechanical rupture and delamination of conducting polymer (CP) films is desirable to prevent failure of devices based on these materials. Thus, precise in situ measurement of voltage-induced stress within these films should provide insight into the cause of these failure mechanisms. The evolution of stress in films of polypyrrole (pPy), doped with indigo carmine (IC), was measured in different electrochemical environments using the multibeam optical stress sensor (MOSS) technique. The stress in these films gradually increases to a constant value during voltage cycling, revealing an initial break-in period for CP films. The nature of the ions involved in charge compensation of pPy[IC] during voltage cycling was determined from electrochemical quartz crystal microbalance (EQCM) data. The magnitude of the voltage-induced stress within pPy[IC] at neutral pH correlated with the radius of the hydrated mobile ion in the order Li(+) > Na(+) > K(+). At acidic pH, the IC dopant in pPy[IC] undergoes reversible oxidation and reduction within the range of potentials investigated, providing a secondary contribution to the observed voltage-induced stress. We report on the novel stress response of these polymers due to the presence of pH-dependent redox-active dopants and how it can affect material performance.

  17. Several methods applied to measuring residual stress in a known specimen

    Prime, M.B.; Rangaswamy, P.; Daymond, M.R.; Abelin, T.G.


    In this study, a beam with a precisely known residual stress distribution provided a unique experimental opportunity. A plastically bent beam was carefully prepared in order to provide a specimen with a known residual stress profile. 21Cr-6Ni-9Mn austenitic stainless steel was obtained as 43 mm square forged stock. Several methods were used to determine the residual stresses, and the results were compared to the known values. Some subtleties of applying the various methods were exposed.

  18. Measurement and Analysis on Hardness and Residual Stress of Heavy Forging after Heat Treatment


    The hardness and residual stress in the forging for cold roller during low temperature tempering, and the relationship of residual stress and cooling temperature of high temperature tempering for heavy forgings were studied. The stress relaxation constant at low temperature tempering and the elasto-plastisity inversion temperature at high temperature tempering were found. The results are of great importance to determine rational tempering cooling process of heavy forgings.

  19. Measurement of the stress field of a tunnel through its rock EMR

    Qiu, Liming; Wang, Enyuan; Song, Dazhao; Liu, Zhentang; Shen, Rongxi; Lv, Ganggang; Xu, Zhaoyong


    In order to quantitatively study the relationship between the disturbance stress of coal mine roadways and the electromagnetic radiation (EMR) of rocks, and further evaluate their internal stress distributions, we first examined the characteristics of EMR signals emitted from rock mass under uniaxial compression, analyzed the relationship between the stress inside the rock mass and its emitted EMR intensity, and put forward a new disturbance stress testing method by monitoring the EMR from the rock mass to retrieve its surrounding stress field. Then, we applied the method to monitor EMR intensity from the no.11803 rock roadway of the Nuodong coal mine, China, and inversely retrieved its stress field. Lastly, we analyzed the causes of local stress anomalies in the Nuodong area by testing the EMR intensity of its nearby areas, and we examined the geology of the whole region. The results showed that: (1) in the rock roadway and the surrounding area of the Nuodong coal mine, the disturbance stress was in the range of 4.8 ∼ 9.1 MPa, the angle between the direction of the stress field and the horizontal plane of the roadway was 35 ± 2.5°, the lateral pressure coefficient was 1.30 ∼ 1.57 (2) the Laoguishan and Yulong anticlines in the vicinity of the Nuodong coal mine caused great horizontal tectonic stress in the region, and the existence of the auxiliary roadway and F12 normal fault resulted in the formation of two high stress zones in the no.11803 rock roadway. Overall, monitoring the EMR from rock mass could ascertain the state, direction, size and distribution of disturbance stress in a roadway and further obtain the distribution of the stress field of an underground structure.

  20. Evaluation of Pressure Pain Threshold as a Measure of Perceived Stress and High Job Strain.

    Hven, Lisbeth; Frost, Poul; Bonde, Jens Peter Ellekilde


    To investigate whether pressure pain threshold (PPT), determined by pressure algometry, can be used as an objective measure of perceived stress and job strain. We used cross-sectional base line data collected during 1994 to 1995 within the Project on Research and Intervention in Monotonous work (PRIM), which included 3123 employees from a variety of Danish companies. Questionnaire data included 18 items on stress symptoms, 23 items from the Karasek scale on job strain, and information on discomfort in specified anatomical regions was also collected. Clinical examinations included pressure pain algometry measurements of PPT on the trapezius and supraspinatus muscles and the tibia. Associations of stress symptoms and job strain with PPT of each site was analyzed for men and women separately with adjustment for age body mass index, and discomfort in the anatomical region closest to the point of pressure algometry using multivariable linear regression. We found significant inverse associations between perceived stress and PPT in both genders in models adjusting for age and body mass index: the higher level of perceived stress, the lower the threshold. For job strain, associations were weaker and only present in men. In men all associations were attenuated when adjusting for reported discomfort in regions close to the site of pressure algometry. The distributions of PPT among stressed and non-stressed persons were strongly overlapping. Despite significant associations between perceived stress and PPT, the discriminative capability of PPT to distinguish individuals with and without stress is low. PPT measured by pressure algometry seems not applicable as a diagnostic tool of a state of mental stress.

  1. GSTM1 and APE1 genotypes affect arsenic-induced oxidative stress: a repeated measures study

    Quamruzzaman Quazi


    Full Text Available Abstract Background Chronic arsenic exposure is associated with an increased risk of skin, bladder and lung cancers. Generation of oxidative stress may contribute to arsenic carcinogenesis. Methods To investigate the association between arsenic exposure and oxidative stress, urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG was evaluated in a cohort of 97 women recruited from an arsenic-endemic region of Bangladesh in 2003. Arsenic exposure was measured in urine, toenails, and drinking water. Drinking water and urine samples were collected on three consecutive days. Susceptibility to oxidative stress was evaluated by genotyping relevant polymorphisms in glutathione-s transferase mu (GSTM1, human 8-oxoguanine glycosylase (hOGG1 and apurinic/apyrimidinic endonuclease (APE1 genes using the Taqman method. Data were analyzed using random effects Tobit regression to account for repeated measures and 8-OHdG values below the detection limit. Results A consistent negative effect for APE1 was observed across water, toenail and urinary arsenic models. APE1 148 glu/glu + asp/glu genotype was associated with a decrease in logged 8-OHdG of 0.40 (95%CI -0.73, -0.07 compared to APE1 148 asp/asp. An association between total urinary arsenic and 8-OHdG was observed among women with the GSTM1 null genotype but not in women with GSTM1 positive. Among women with GSTM1 null, a comparison of the second, third, and fourth quartiles of total urinary arsenic to the first quartile resulted in a 0.84 increase (95% CI 0.27, 1.42, a 0.98 increase (95% CI 033, 1.66 and a 0.85 increase (95% CI 0.27, 1.44 in logged 8-OHdG, respectively. No effects between 8-OHdG and toenail arsenic or drinking water arsenic were observed. Conclusion These results suggest the APE1 variant genotype decreases repair of 8-OHdG and that arsenic exposure is associated with oxidative stress in women who lack a functional GSTM1 detoxification enzyme.

  2. Drought stress and carbon uptake in an Amazon forest measured with spaceborne imaging spectroscopy.

    Asner, Gregory P; Nepstad, Daniel; Cardinot, Gina; Ray, David


    Amazônia contains vast stores of carbon in high-diversity ecosystems, yet this region undergoes major changes in precipitation affecting land use, carbon dynamics, and climate. The extent and structural complexity of Amazon forests impedes ground studies of ecosystem functions such as net primary production (NPP), water cycling, and carbon sequestration. Traditional modeling and remote-sensing approaches are not well suited to tropical forest studies, because (i) biophysical mechanisms determining drought effects on canopy water and carbon dynamics are poorly known, and (ii) remote-sensing metrics of canopy greenness may be insensitive to small changes in leaf area accompanying drought. New spaceborne imaging spectroscopy may detect drought stress in tropical forests, helping to monitor forest physiology and constrain carbon models. We combined a forest drought experiment in Amazônia with spaceborne imaging spectrometer measurements of this area. With field data on rainfall, soil water, and leaf and canopy responses, we tested whether spaceborne hyperspectral observations quantify differences in canopy water and NPP resulting from drought stress. We found that hyperspectral metrics of canopy water content and light-use efficiency are highly sensitive to drought. Using these observations, forest NPP was estimated with greater sensitivity to drought conditions than with traditional combinations of modeling, remote-sensing, and field measurements. Spaceborne imaging spectroscopy will increase the accuracy of ecological studies in humid tropical forests.

  3. Environmentally friendly pavements: Results from noise measurements 2005-2008

    Berge, Truls Svenn; Haukland, Frode; Ustad, Asbjørn


    CPX-measurements (tyre A) have been performed on a wide range of ordinary dense Norwegian road pavements and special test pavements, as part of the R&D project “Environmental friendly pavements” initiated by the Norwegian Public Roads Administration. The following conclusions can be made from the investigation:- New dense asphalt concrete pavements can give a tyre/road noise level (CPX) of 4-8 dB(A) lower noise level, compared to a chosen reference level for a pavement of type AC 0/11 and SMA...

  4. Measurement of in-situ stress in salt and rock using NQR techniques

    Schempp, E.; Hirschfeld, T.; Klainer, S.


    A discussion of how stress and strain affect the quantities which can be measured in an NQR experiment shows that, for stresses of the magnitude to be expected at depths up to about 10,000 feet, quadrupole coupling constants will fall in the range of 1 to 10 kHz for both the sodium and chloride ions in NaCl. The most promising system involves pulsed nuclear double resonance detection; and alterative is to observe the quadrupolar splitting of the NMR signal. Choices to be made in the measurement and mapping techniques are discussed. The well-known perturbation of the homogenous stress field in the neighborhood of a borehole is shown to be advantageous from the point of view of obtaining directional information on the stress. Construction and operation of a borehole stress sensor are considered. The NQR technique seems feasible for measuring the magnitude and direction of underground stress with a resolution of about 25 psi, or 2.5% at 1000 psi. Downhole instrumentation suitable for in-situ determinations of stress appears within the state of the art. Additional tasks required on the project are identified.

  5. First measurements results of the LHC longitudinal density monitor

    Jeff , A; Bravin, E; Boccardi, A; Bozyigit, S; Lefevre, T; Rabiller, A; Roncarolo, F; Welsch, C P; Fisher, A S


    Knowledge of the longitudinal distribution of particles is important for various aspects of accelerator operation, for example to check the injection quality and to characterize the development of ghost bunches before and during the physics periods. A new detector, the LHC Longitudinal Density Monitor (LDM) is a single-photon counting system measuring synchrotron light by means of an avalanche photodiode detector. The unprecedented energies reached in the LHC allow synchrotron light diagnostics to be used with both protons and heavy ions. The LDM is able to longitudinally profile the whole ring with a resolution close to the target of 50 ps. On-line correction for the effects of the detector deadtime, pile-up and afterpulsing allow a dynamic range of 105 to be achieved. The LDM operated during the 2010 lead ion run and during 2011 with protons. Measurements from both runs are presented in this contribution along with an analysis of the LDM performance and an outlook for future upgrades.

  6. R&D and Productivity: Measurement Issues and Econometric Results.

    Griliches, Zvi


    Discusses the relationship and contributions of research and development (R&D) to productivity growth in the United States. Focuses on the impacts of industrial R&D and presents study results on trends in productivity. (ML)

  7. Emotion self-regulation, psychophysiological coherence, and test anxiety: results from an experiment using electrophysiological measures.

    Bradley, Raymond Trevor; McCraty, Rollin; Atkinson, Mike; Tomasino, Dana; Daugherty, Alane; Arguelles, Lourdes


    This study investigated the effects of a novel, classroom-based emotion self-regulation program (TestEdge) on measures of test anxiety, socioemotional function, test performance, and heart rate variability (HRV) in high school students. The program teaches students how to self-generate a specific psychophysiological state--psychophysiological coherence--which has been shown to improve nervous system function, emotional stability, and cognitive performance. Implemented as part of a larger study investigating the population of tenth grade students in two California high schools (N = 980), the research reported here was conducted as a controlled pre- and post-intervention laboratory experiment, using electrophysiological measures, on a random stratified sample of students from the intervention and control schools (N = 136). The Stroop color-word conflict test was used as the experiment's stimulus to simulate the stress of taking a high-stakes test, while continuous HRV recordings were gathered. The post-intervention electrophysiological results showed a pattern of improvement across all HRV measures, indicating that students who received the intervention program had learned how to better manage their emotions and to self-activate the psychophysiological coherence state under stressful conditions. Moreover, students with high test anxiety exhibited increased HRV and heart rhythm coherence even during a resting baseline condition (without conscious use of the program's techniques), suggesting that they had internalized the benefits of the intervention. Consistent with these results, students exhibited reduced test anxiety and reduced negative affect after the intervention. Finally, there is suggestive evidence from a matched-pairs analysis that reduced test anxiety and increased psychophysiological coherence appear to be directly associated with improved test performance--a finding consistent with evidence from the larger study.

  8. The Border Community & Immigration Stress Scale: A Preliminary Examination of a Community Responsive Measure in Two Southwest Samples

    Carvajal, Scott C.; Rosales, Cecilia; Rubio-Goldsmith, Raquel; Sabo, Samantha; Ingram, Maia; McClelland, Debra Jean; Redondo, Floribella; Torres, Emma; Romero, Andrea J.; Oleary, Anna Ochoa; Sanchez, Zoila; de Zapien, Jill Guernsey


    Background Understanding contemporary socio-cultural stressors may assist educational, clinical and policy-level health promotion efforts. This study presents descriptive findings on a new measure, the Border Community & Immigration Stress Scale (BCISS). Methods The data were from two community surveys as part of community based participatory projects conducted in the Southwestern US border region. This scale includes stressful experiences reflected in extant measures, with new items reflecting heightened local migration pressures and health care barriers. Results Stressors representing each main domain, including novel ones, were reported with frequency and at high intensity in the predominantly Mexican-descent samples. Total stress was also significantly associated with mental and physical health indicators. Discussion The study suggests particularly high health burdens tied to the experience of stressors in the US border region. Further, many of the stressors are also likely relevant for other communities within developed nations also experiencing high levels of migration. PMID:22430894

  9. Analytical methods for the measurement of polymerization kinetics and stresses of dental resin-based composites: A review

    Ghavami-Lahiji, Mehrsima; Hooshmand, Tabassom


    Resin-based composites are commonly used restorative materials in dentistry. Such tooth-colored restorations can adhere to the dental tissues. One drawback is that the polymerization shrinkage and induced stresses during the curing procedure is an inherent property of resin composite materials that might impair their performance. This review focuses on the significant developments of laboratory tools in the measurement of polymerization shrinkage and stresses of dental resin-based materials during polymerization. An electronic search of publications from January 1977 to July 2016 was made using ScienceDirect, PubMed, Medline, and Google Scholar databases. The search included only English-language articles. Only studies that performed laboratory methods to evaluate the amount of the polymerization shrinkage and/or stresses of dental resin-based materials during polymerization were selected. The results indicated that various techniques have been introduced with different mechanical/physical bases. Besides, there are factors that may contribute the differences between the various methods in measuring the amount of shrinkages and stresses of resin composites. The search for an ideal and standard apparatus for measuring shrinkage stress and volumetric polymerization shrinkage of resin-based materials in dentistry is still required. Researchers and clinicians must be aware of differences between analytical methods to make proper interpretation and indications of each technique relevant to a clinical situation. PMID:28928776

  10. Surface preparation for XRD residual stress measurements; Preparacao de superficie para medicao de tensoes residuais em soldagem por DRX

    Mishchenko, Andrii; Oliveira, Bruno Jose de; Scotti, Americo, E-mail:, E-mail:, E-mail: [Universidade Federal de Uberlandia (UFU), MG (Brazil)


    A characteristic feature of the X Ray Diffraction (XRD) method for stress determination is that measurements occur at a thin surface layer. Steel sheets come with surfaces modified by lamination, cleaning (sandblasting, grinding) and even corrosion, which induce residual stresses or roughness inherent to the material. Therefore, surface preparation prior to the residual stress measurement is essential, although no standard procedure seems to be available. A general recommendation is to remove a thin layer so that only residual stresses related to the welding process will be measured. In this study, the use of portable electrolytic equipment was evaluated for mechanized surface material removal. Chemical compositions of electrolytic solutions and the influence of current on the removed material, removal time and temperature during the process were studied. As a result, a suitable chemical solution for electro etching of low carbon steel was developed and a set of “soft” parameters that allowed the removal of about 300 um in a reasonable time was found. Higher currents reduce the removal time, yet increasing the consumption of the solution and plate temperature (which could adversely alter the microstructure or generate thermal stresses). Furthermore, the influence of these parameters on the operability of the process was demonstrated. (author)

  11. Acoustic Measurements of Residual Stresses and Grain Sizes in Aluminum Alloys

    Fisher, Martin John

    The theory of acoustoelasticity relates the velocity of an acoustic wave in a solid to the elastic stress state in that solid. This thesis presents new theories, measurement techniques, and methodologies related to the use of longitudinal wave acoustoelasticity in aluminum alloys. A one-dimensional model has been developed to provide a simple understanding of the acoustoelastic effect. A new acoustic device for accurately measuring relative thickness variations has been designed and built. This device is used--in conjunction with a pulse-echo phase measurement device and a computer controlled scanning system--to measure acoustic velocity variations in plastically deformed and non-flat-and-parallel samples. Acoustic velocity variations from point to point in an unstressed sample can sometimes be on the same order as velocity changes due to applied or residual stresses, and this can make stress measurements difficult. A statistical theory has been developed to relate these unstressed velocity variations to the average grain size in the sample and to the active area of the acoustic transducer used. Large transducers and small grain sizes will minimize these variations. This relationship has been verified by tests on a number of aluminum alloys and a new method for non-destructive grain size determination has been suggested. A systematic methodology has been developed and tested for studying the influence of uniaxial plastic deformation on the acoustoelastic response. Samples have been plastically deformed in four-point bending to produce elastic-plastic and residual stress states. Acoustic measurements of these stresses have then been compared directly to theoretical predictions based on the materials' stress-strain curves and simple beam theory. In the aluminum alloys tested (2024-T351 and 7075-T651), the acoustoelastic constants are shown to be virtually unchanged by uniaxial plastic strains of less than 2.5%. Thus, the acoustoelastic technique can be reliably

  12. Serial measurements of exercise performance in pediatric heart transplant patients using stress echocardiography.

    Yeung, Joanne P; Human, Derek G; Sandor, George G S; De Souza, Astrid M; Potts, James E


    Heart transplantation is an increasingly acceptable therapeutic option for children with end-stage and complex congenital heart disease. With advances in surgery, immunosuppression, and follow-up care, functional outcomes need to be evaluated. We report the results of serial exercise testing performed using stress echocardiography in a cohort of pediatric HTP. HTP (n = 7) exercised on a semi-recumbent ergometer to volitional fatigue. Echocardiography-Doppler measurements, HR, and blood pressure were taken at rest and during staged exercise. Results were compared with healthy CON (n = 12). HTP did significantly less work during exercise (940 vs. 1218 J/kg, p HTP had a lower SF at peak exercise (48% vs. 52%, p HTP. HTP are able to exercise safely; however, their exercise tolerance is reduced, and hemodynamics and contractility are diminished. Over time, their hemodynamics and left ventricular function have remained relatively constant.

  13. A Novel Instrument and Methodology for the In-Situ Measurement of the Stress in Thin Films

    Broadway, David M.; Omokanwaye, Mayowa O.; Ramsey, Brian D.


    We introduce a novel methodology for the in-situ measurement of mechanical stress during thin film growth utilizing a highly sensitive non-contact variation of the classic spherometer. By exploiting the known spherical deformation of the substrate the value of the stress induced curvature is inferred by measurement of only one point on the substrate's surface-the sagittal. From the known curvature the stress can be calculated using the well-known Stoney equation. Based on this methodology, a stress sensor has been designed which is simple, highly sensitive, compact, and low cost. As a result of its compact nature, the sensor can be mounted in any orientation to accommodate a given deposition geometry without the need for extensive modification to an already existing deposition system. The technique employs the use of a double side polished substrate that offers good specular reflectivity and is isotropic in its mechanical properties, such as oriented crystalline silicon or amorphous soda lime glass, for example. The measurement of the displacement of the uncoated side during deposition is performed with a high resolution (i.e. 5nm), commercially available, inexpensive, fiber optic sensor which can be used in both high vacuum and high temperature environments (i.e. 10(exp-7) Torr and 480oC, respectively). A key attribute of this instrument lies in its potential to achieve sensitivity that rivals other measurement techniques such as the micro cantilever method but, due to the comparatively larger substrate area, offers a more robust and practical alternative for subsequent measurement of additional characteristics of the film that can might be correlated to film stress. We present measurement results of nickel films deposited by magnetron sputtering which show good qualitative agreement to the know behavior of polycrystalline films previously reported by Hoffman.

  14. Revisions and further developments of the occupational stress indicator: Lisrel results from four dutch studies.

    Evers, A.; Frese, M.; Cooper, C.L.


    The Occupational Stress Indicator (OSI) is a popular instrument for the diagnosis of stress and stress-related personality and outcome variables. However, one weakness of the OSI was the low reliability of some of its scales. This paper describes in a series of 4 studies improvements of the

  15. Measures of Model Uncertainty in the Assessment of Primary Stresses in Ship Structures

    Östergaard, Carsten; Dogliani, Mario; Guedes Soares, Carlos;


    The paper considers various models and methods commonly used for linear elastic stress analysis and assesses the uncertainty involved in their application to the analysis of the distribution of primary stresses in the hull of a containership example, through statistical evaluations of the results...

  16. An automated system for the measurement of magnetostriction in electrical steel sheet under applied stress

    Anderson, P I; Stanbury, H J


    The design of an automated system for the rapid assessment of the AC magnetostriction in electrical steel sheet under linear applied stress in the range +-10 MPa is described in detail. Typical results are presented showing the effect of induction on the unstressed material together with plots of the harmonics of magnetostriction and specific total loss versus applied stress.

  17. Residual stress measurement with high energy x-rays at the Advanced Photon Source.

    Winholtz, R. A.; Haeffner, D. R.; Green, R.E.L.; Varma, R.; Hammond, D.


    Preliminary measurements with high energy x-rays from the SRI CAT 1-ID beam line at the Advanced Photon show great promise for the measurement of stress and strain using diffraction. Comparisons are made with neutron measurements. Measurements of strains in a 2 mm thick 304 stainless steel weld show that excellent strain and spatial resolutions are possible. With 200 {micro}m slits, strain resolutions of 1 x 10{sup {minus}5} were achieved.

  18. Multiple Osmotic Stress Responses in Acidihalobacter prosperus Result in Tolerance to Chloride Ions

    Dopson, Mark; Holmes, David S.; Lazcano, Marcelo; McCredden, Timothy J.; Bryan, Christopher G.; Mulroney, Kieran T.; Steuart, Robert; Jackaman, Connie; Watkin, Elizabeth L. J.


    Extremely acidophilic microorganisms (pH optima for growth of ≤3) are utilized for the extraction of metals from sulfide minerals in the industrial biotechnology of “biomining.” A long term goal for biomining has been development of microbial consortia able to withstand increased chloride concentrations for use in regions where freshwater is scarce. However, when challenged by elevated salt, acidophiles experience both osmotic stress and an acidification of the cytoplasm due to a collapse of the inside positive membrane potential, leading to an influx of protons. In this study, we tested the ability of the halotolerant acidophile Acidihalobacter prosperus to grow and catalyze sulfide mineral dissolution in elevated concentrations of salt and identified chloride tolerance mechanisms in Ac. prosperus as well as the chloride susceptible species, Acidithiobacillus ferrooxidans. Ac. prosperus had optimum iron oxidation at 20 g L−1 NaCl while At. ferrooxidans iron oxidation was inhibited in the presence of 6 g L−1 NaCl. The tolerance to chloride in Ac. prosperus was consistent with electron microscopy, determination of cell viability, and bioleaching capability. The Ac. prosperus proteomic response to elevated chloride concentrations included the production of osmotic stress regulators that potentially induced production of the compatible solute, ectoine uptake protein, and increased iron oxidation resulting in heightened electron flow to drive proton export by the F0F1 ATPase. In contrast, At. ferrooxidans responded to low levels of Cl− with a generalized stress response, decreased iron oxidation, and an increase in central carbon metabolism. One potential adaptation to high chloride in the Ac. prosperus Rus protein involved in ferrous iron oxidation was an increase in the negativity of the surface potential of Rus Form I (and Form II) that could help explain how it can be active under elevated chloride concentrations. These data have been used to create a


    Enikeev A.G.


    Full Text Available The gene technology using in plant investigations came to the better understanding of plant physiological processes. At the same time unclear knowledge about transgenic plant physiology may occur a source of incorrect interpretation of obtained results and, consequently, wrong conclusions. In addition, the causes and mechanisms of pleiotropic effects associated with transgenic insertion and gene silencing are remaining unexplained. To solve the problem of transgenic plant physiology it is necessary to pay a close attention to physiological and biochemical peculiarities of plant-agrobacterium symbiosis, because it is a base of plant transformation. It was assumed earlier that agrobacterial transformation is a complex biotic stressing factor and transgenic plant is a long-term stressed organism. We suppose that physiological consequences of plant transformation are determined not only by foreign gene insertion, but largely by stress reaction of plant cells on agrobacterium transformation. Foreign DNA insertion to the plant recipient results in cascade of response reactions remarkably changing metabolism. The degree of such response is supposed to be in dependence on phylogenetic relations of gene donor and recipient. Cell cultures were obtained from tobacco plants (Nicotiana tabacum cv. ’Samsung’ transformed by following Agrobacterium tumefaciens strains: disarmed 669 one and LBA4400 one with hsp 101 in sense or antisense orientation. These cell cultures were used for investigations of the stress-reactions on biotic (bacterial infection agent Clavibacter michiganensis subsp. Sepedonicus and abiotic (high temperature, potassium fluoride factors. It was revealed that “sense” culture was superior to normal and “699” ones in tolerance to pointed stressing factors. Similar results were obtained for “antisense” culture, nevertheless it was a priori not expected to be tolerant. So, to assess the transformation consequence is necessary to

  20. Self-oscillation acoustic system destined to measurement of stresses in mass rocks

    Kwasniewski, Janusz; Dominik, Ireneusz; Dorobczynski, Lech


    The paper presents an electronic self-oscillation acoustic system (SAS) destined to measure of stresses variations in the elastic media. The system consists of piezoelectric detector, amplifier-limiter, pass-band filter, piezoelectric exciter and the frequency meter. The mass rock plays a role of delaying element, in which variations in stresses causing the variations of acoustic wave velocity of propagation, and successive variation in frequency of oscillations generated by system. The laboratory test permitted to estimate variations in frequency caused by variations in stresses of elastic medium. The principles of selection of frequency and other parameters of the electronic system in application to stresses measurement in condition of the mine were presented.

  1. Measurement and tailoring of residual stress in expanded austenite on austenitic stainless steel

    Fernandes, Frederico Augusto Pires; Christiansen, Thomas Lundin; Winther, Grethe


    Expanded austenite on stainless steel with a high interstitial nitrogen content is characterized by elasto-plastic accommodation of the large composition-induced lattice expansion leading to huge compressive residual stress. The elasto-plastic accommodation as well as the (steep) concentration...... profile has implications for the measurement strategy to determine lattice strains and associated residual stresses with X-ray diffraction. Lattice strain measurements were performed on nitrided as well as subsequently de-nitrided expanded austenite on AISI 316L stainless steel, for various grazing...... stresses in expanded austenite can be tailored by de-nitriding after nitriding, such that a condition of virtually zero stress at the surface is obtained....

  2. Stress

    ... diabetes. Your Stress-Free System for Family Dinners! - 2017-03-book-oclock-scramble.html Your Stress-Free System for Family Dinners! A year of delicious meals to help prevent ...

  3. Stress

    ... sudden negative change, such as losing a job, divorce, or illness Traumatic stress, which happens when you ... stress, so you can avoid more serious health effects. NIH: National Institute of Mental Health

  4. Spatial Resolution Correction for Electrochemical Wall-shear Stress Measurements using Rectangular Sensors

    Fethi Aloui


    Full Text Available This article is mainly motivated by the growing needs for highly resolved measurements for wall-bounded turbulent flows and aims to proposes a spatial correction coefficient in order to increase the wall-shear stress sensors accuracy. As it well known for the hot wire anemometry, the fluctuating streamwise velocity measurement attenuation is mainly due to the spatial resolution and the frequency response of the sensing element. The present work agrees well with this conclusion and expands it to the wall-shear stress fluctuations measurements using electrochemical sensors and suggested a correction method based on the spanwise correlation coefficient to take into account the spatial filtering effects on unresolved wall-shear stress measurements due to too large sensor spanwise size.

  5. An accelerometer based system to measure myocardial performance index during stress testing.

    Anh Dinh; Bui, Francis M; Tam Nguyen


    Stress testing is used to measure the performance of the heart in an elevated stress state, in order to monitor or diagnose certain heart problems. Many measurements can be used to determine the performance of the heart, with the Tei index being the measurement of interest in this work. The Tei index has been used as a reliable method to evaluate systolic and diastolic performance, as it overcomes some limitations of the classical echocardiographic indices. It is calculated based on the time intervals derived from echocardiography. This paper presents an exploratory study, which uses an accelerometer to record mechanical events occurring in each cardiac cycle, also known as the seismocardiogram (SCG). From timing measurements corresponding to various events in the heart, a metric for myocardial performance is calculated based on the Tei index. The use of SCG in addition to ECG has the potential to provide further insights about the heart during stress testing, since the SCG quantifies mechanical actions of the heart.

  6. The STAR W Program : New Results and Future Measurements

    Seele, Joseph


    The production of $W^\\pm$ bosons in longitudinally polarized p+p collisions at RHIC provides a new means of studying the spin-flavour asymmetries of the proton sea quark spin distributions. Details of the W$^\\pm$ event selection through the $e^\\pm$ decay channel at mid-rapidity are presented, along with preliminary results for the production cross section and parity-violating single-spin asymmetry, $A_L$, from the STAR Collaboration's 2009 data set at $\\sqrt{s} = 500$ GeV. Lastly, the expected sensitivities for future running are discussed.

  7. In situ stress and nanogravimetric measurements during underpotential deposition of bismuth on (111)-textured Au.

    Stafford, G R; Bertocci, U


    The surface stress associated with the underpotential deposition (upd) of bismuth on (111)-textured Au is examined, using the wafer curvature method, in acidic perchlorate and nitrate supporting electrolyte. The surface stress is correlated to Bi coverage by independent nanogravimetric measurements using an electrochemical quartz crystal nanobalance. The mass increase measured in the presence of perchlorate is consistent with the (2 x 2) and (p x square root 3)-2Bi adlayers reported in the literature. ClO(4)(-) does not play a significant role in the upd process. The complete Bi monolayer causes an overall surface stress change of about -1.4 N m(-1). We attribute this compressive stress to the formation of Bi-Au bonds which partially satisfy the bonding requirements of the Au surface atoms, thereby reducing the tensile surface stress inherent to the clean Au surface. At higher Bi coverage, an additional contribution to the compressive stress is due to the electrocompression of the (p x square root 3)-2Bi adlayer. In nitric acid electrolyte, NO(3)(-) coadsorbs with Bi over the entire upd region but has little fundamental impact on adlayer structure and stress.

  8. Transducer for measuring normal and friction stress in contact zone during rolling

    Henningsen, Poul; Wanheim, Tarras; Arentoft, Mogens


    by the friction conditions. To achieve this important information, measurements of the normal pressure and friction stresses in the deformation zone are requested. The interface conditions are analyzed by several authors [1-8] The direction of the friction stress is changing during the rolling gap....... At the entrance of the deformation zone, the peripherical velocity of the roll is higher than for the incoming material, which causes frictional stresses at the material acting in the rolling direction. At the outlet of the rolling gap, the velocity of the deformed material exceeds the velocity of the roll...

  9. The distorting effect of varying diets on fecal glucocorticoid measurements as indicators of stress

    Kalliokoski, Otto; Teilmann, A. Charlotte; Abelson, Klas S. P.


    The physiological stress response is frequently gauged in animals, non-invasively, through measuring glucocorticoids in excreta. A concern with this method is, however, the unknown effect of variations in diets on the measurements. With an energy dense diet, leading to reduced defecation, will low...

  10. Psychological and physiological responses to stress: a review based on results from PET and MRI studies

    Cortez, Celia Martins; Cruz, Frederico Alan de Oliveira; Silva, Dilson [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Inst. de Biologia Roberto Alcantara Gomes. Dept. de Ciencias Fisiologicas]. E-mail:


    A new application for the nuclear imaging techniques is the study of organic responses to stress. Neuroimaging techniques allow the assessment of brain activation changes in association with the metabolic responses to stress. In this paper, a review of general effects of the stress on organic activity is made, emphasizing important advances introduced by studies using PET and fMRI. The importance of the hypothalamus-pituitary-adrenal axis to onset the adequate psychical and organic responses to sustain the homeostasis during the stress is discussed, as well as the possibility of traumatic stressing experiences have negative effects on the brain. (author)

  11. Measuring Thermal Stress of Dairy Cattle Based on Temperature Humidity Index (THI) in Tropical Climate

    Sugiono; Dewi Hardiningtyas; Rudy Soenoko


    Thermal comfort for workers is very important factor to increase their performance, as well as the comfort level of dairy cattle will influence in milk productivity. The purposes of the paper is to measure the level of heat stress and then use the information to design the dairy cattle house for increasing thermal comfort. The research is started with literature review of heat stress and early survey of environment condition e.g. temperature, wind speed and relative humidity. The next step is...

  12. Measured Zero Net Energy Performance: Results, Lessons, and Surprises

    Brown, Carrie; LaRue, Anna; Pigman, Margaret; Roberts, Jon; Kaneda, David; Connelly, Dylan; Elliott, John; Pless, Shanti; Pande, Abhijeet; Dean, Edward; Anbarlilar, Can


    As more and more zero net energy (ZNE) buildings are built and monitored, we can learn from both careful case studies of individual projects as well as a broader perspective of trends over time. In a forum sponsored by Pacific Gas and Electric Company (PG&E), eight expert speakers discussed: results and lessons from monitoring occupied ZNE buildings; best practices for setting performance targets and getting actionable performance information, and; things that have surprised them about monitored ZNE buildings. This paper distills the content of the forum by laying out the most common hurdles that are encountered in setting up monitoring projects, frequent performance issues that the monitoring uncovers, and lessons learned that can be applied to future projects.

  13. Impact of Ramadan Intermittent Fasting on Oxidative Stress Measured by Urinary 15-F2t-Isoprostane

    Mo'ez Al-Islam Ezzat Faris


    fast Ramadan were recruited. Urine and serum sampling and anthropometric and dietary assessments were conducted one week before Ramadan (T0, at the end of the third week of Ramadan (T1, and one month after Ramadan (T2. Biochemical measurements included urinary 15FIP, creatinine, and hematological indices. Results revealed that the urinary level of 15FIP measured at T0 was normal, while they showed a significantly (P<0.05 higher level when measured at T1 concomitant with a significant (P<0.05 increase in the body weight and total body fat percent. In conclusion, results suggest that increased body weight is associated with increased lipid peroxidation and oxidative stress, and the impact of RIF on oxidative stress is mediated by the changes in body weight at the end of the month.

  14. Role Stress and Work Engagement as Antecedents of Job Satisfaction: Results From Portugal

    Daniel Moura


    Full Text Available With more organizations looking for employees who take initiative and respond creatively to the challenges of the job, engagement becomes important at both individual and organizational levels. Engaged employees are generally more satisfied with their work, committed and effective at work. According to the JDR model (Schaufeli & Bakker, 2004, engagement may be produced by two types of working conditions: job demands (i.e., role stress and job resources (i.e., self-efficacy. This study examines the role of role stress (role ambiguity and role conflict and work engagement as antecedents of job satisfaction. A cross sectional study using online questionnaires was conducted. The sample consisted of 312 Portuguese workers. Hierarchical multiple regressions analyses have revealed that job satisfaction was significantly predicted by role conflict and work engagement. Results support JDR model by showing that positive outcomes, such as job satisfaction, may be predicted by motivational process and job demands. On a practical level, JDR model provides a framework for understanding motivating workplaces and engaged and satisfied employees.

  15. Spreading of intolerance under economic stress: Results from a reputation-based model

    Martinez-Vaquero, Luis A.; Cuesta, José A.


    When a population is engaged in successive prisoner's dilemmas, indirect reciprocity through reputation fosters cooperation through the emergence of moral and action rules. A simplified model has recently been proposed where individuals choose between helping others or not and are judged good or bad for it by the rest of the population. The reputation so acquired will condition future actions. In this model, eight strategies (referred to as "leading eight") enforce a high level of cooperation, generate high payoffs, and are therefore resistant to invasions by other strategies. Here we show that, by assigning each individual one of two labels that peers can distinguish (e.g., political ideas, religion, and skin color) and allowing moral and action rules to depend on the label, intolerant behaviors can emerge within minorities under sufficient economic stress. We analyze the sets of conditions where this can happen and also discuss the circumstances under which tolerance can be restored. Our results agree with empirical observations that correlate intolerance and economic stress and predict a correlation between the degree of tolerance of a population and its composition and ethical stance.

  16. Feasibility of using a biowatch to monitor GSR as a measure of radiologists' stress and fatigue

    Krupinski, Elizabeth A.; MacKinnon, Lea; Reiner, Bruce I.


    We have been investigating the impact of fatigue on diagnostic performance of radiologists interpreting medical images. In previous studies we found evidence that eye strain could be objectively measured and that it correlates highly with degradations in diagnostic accuracy as radiologists work long hours. Eye strain however can be difficult to measure in a non-invasive and continuous manner over the work day so we have been investigating other ways to measure physiological stress and fatigue. In this study we evaluated the feasibility of using a commercially available biowatch to measure galvanic skin response (GSR), a well known indicator of stress. 10 radiology residents wore the biowatch for about 8 hours during their normal work day and data were automatically collected at 10 Hz. They completed the Swedish Occupational Fatigue Inventory (SOFI) at the start and finish of the day. GSR values (microsiemens) ranged from 0.14 to 38.27 with an average of 0.50 (0.28 median). Overall GSR tended to be fairly constant as the day progressed, but there were definite spikes indicating higher levels of stress. SOFI scores indicated greater levels of fatigue and stress at the end of the work day. Although further work is needed, GSR measurements obtained via an easy to wear watch may provide a means to monitor stress/fatigue and alert radiologists when to take a break from interpreting images to avoid making errors.

  17. Measuring wheel/rail contact stresses using ultrasound

    Marhsall, M.B.; Lewis, R.; Dwyer-Joyce, R.S.; Olofsson, O.; Bjorklund, S


    The investigation of contact area and pressure distribution in a wheel/rail contact is essential information required in fatigue and wear calculations to determine design life, regrinding requirements, and maintenance schedules. The aim of this work was to use ultrasound to non-destructively determine wheel/rail contact pressures. Three different contacts were investigated those resulting from; un-used, sand damaged, and worn wheel/rail specimens. \\ud \\ud A wheel/rail interface behaves like a...

  18. Differential effect of severe and moderate social stress on blood immune and endocrine measures and susceptibility to collagen type II arthritis in male rats.

    Stefanski, Volker; Hemschemeier, Susanne K; Schunke, Kerstin; Hahnel, Anja; Wolff, Christine; Straub, Rainer H


    The effects of social stress on several blood immune measures and collagen-induced arthritis (CIA) were investigated in Wistar rats using the resident-intruder confrontation paradigm to induce stress of different intensity. Male intruders were exposed for one week to a dominant opponent either repeatedly for 4h daily (moderate stress) or continuously (severe stress). Arthritis was induced by intradermal injection of collagen type II (CII) into the tail skin at the end of day 3 of confrontation. Only severe stress was associated with decreased CD4 and CD8 T cells, and the increase in granulocyte numbers and body mass loss was more pronounced under these conditions. Only severe stress reduced the susceptibility to arthritis by about 50%. Severity scores did not differ in the first five days after disease onset between all groups. Subsequent experiments focused on severely stressed rats indicated that disease progressed until day 10 only in control animals, but not in severely stressed males. Stressor exposure resulted in increased blood monocyte numbers, but these males failed to accumulate macrophages into the skin at the site of CII injection. High numbers of attacks experienced by intruders correlated with delayed disease onset in severely stressed rats. We hypothesize that severe stress persisting after disease induction exhibits beneficial effects on the susceptibility of CIA and propose that the specific endocrine and immunological profile associated with severe stress is an important factor for disease outcome--a factor which probably explains many of the conflicting data of previous stress studies on CIA.

  19. Treating fibromyalgia with mindfulness-based stress reduction: results from a 3-armed randomized controlled trial.

    Schmidt, Stefan; Grossman, Paul; Schwarzer, Barbara; Jena, Susanne; Naumann, Johannes; Walach, Harald


    Mindfulness-based stress reduction (MBSR) is a structured 8-week group program teaching mindfulness meditation and mindful yoga exercises. MBSR aims to help participants develop nonjudgmental awareness of moment-to-moment experience. Fibromyalgia is a clinical syndrome with chronic pain, fatigue, and insomnia as major symptoms. Efficacy of MBSR for enhanced well-being of fibromyalgia patients was investigated in a 3-armed trial, which was a follow-up to an earlier quasi-randomized investigation. A total of 177 female patients were randomized to one of the following: (1) MBSR, (2) an active control procedure controlling for nonspecific effects of MBSR, or (3) a wait list. The major outcome was health-related quality of life (HRQoL) 2 months post-treatment. Secondary outcomes were disorder-specific quality of life, depression, pain, anxiety, somatic complaints, and a proposed index of mindfulness. Of the patients, 82% completed the study. There were no significant differences between groups on primary outcome, but patients overall improved in HRQoL at short-term follow-up (P=0.004). Post hoc analyses showed that only MBSR manifested a significant pre-to-post-intervention improvement in HRQoL (P=0.02). Furthermore, multivariate analysis of secondary measures indicated modest benefits for MBSR patients. MBSR yielded significant pre-to-post-intervention improvements in 6 of 8 secondary outcome variables, the active control in 3, and the wait list in 2. In conclusion, primary outcome analyses did not support the efficacy of MBSR in fibromyalgia, although patients in the MBSR arm appeared to benefit most. Effect sizes were small compared to the earlier, quasi-randomized investigation. Several methodological aspects are discussed, e.g., patient burden, treatment preference and motivation, that may provide explanations for differences. In a 3-armed randomized controlled trial in female patients suffering from fibromyalgia, patients benefited modestly from a mindfulness

  20. Review of Stress and the Measurement of Stress in Marine Mammals


    et al., 2006). Hair shaft cortisol will be determined using a technique recently validated for use in free-ranging terrestrial mammals ( Macbeth et...extracted into methanol, reconstituted in phosphate buffer, and measured using a commercially available enzyme- linked immunosorbent assay ( Macbeth ...species of delphinids. Marine Mammal Science 22, 1-16. Macbeth , B. J., Cattet, M. R. L., Stenhouse, G. B., Gibeau, M. L., and Janz, D. M. 2010. Hair


    Smaranda CIMPOERU


    Full Text Available Measuring financial stress is a key research issue that has gained a lot of interest in the years following the extreme events from 2007. Although a lot of models were used for assessing and measuring financial stress, none of the managed to forecast the global crisis from 2007. We can identify three generation of models plus the approach of measuring the probability of a crisis with financial stress indexes. In our paper, we review briefly the most important approaches in measuring financial stress from the specialty literature and we propose a case study for European countries. We apply a logistic regression model for panel data, using macroeconomic indicators with the goal of finding the most important triggers for a financial crisis or otherwise said, the early warning signals of a crisis. We obtain very good accuracy of the proposed model (85% and the results are of great importance for policy makers and also for researchers. The study highly contributes to the specialty literature, considering that it is the first early warning system developed on macroeconomic indicators only for European advanced and emerging economies. Moreover, it includes in the analysis a period of five year following 2007.

  2. Evolution of asthenospheric layers as a result of changing temperature and stress fields

    Czechowski, Leszek; Grad, Marek


    The lithosphere is underlain by the asthenosphere. Traditionally, the boundary between the lithosphere and the asthenosphere (LAB) is defined by a difference in response to stress: the lithosphere remains elastic or brittle, while the asthenosphere deforms viscously and accommodates strain through plastic deformation. The reology of rocks depends on many factors: temperature, pressure, chemical composition, size of grains, etc. However, the basic differences of lithosphere and asthenosphere properties could be explained as a result of the temperature and pressure. The effective viscosity of mantle is proportional to C exp(A q), where q is the ratio (melting temperature/temperature), C and A are positive constants. The mantle is not molten, so q >1. If the temperature is close to the melting temperature then q is close to 1 and effective viscosity is low (e.g. 1018 Pa s). This situation is observed in asthenosphere. The lithosphere is a thermal boundary layer for the convection in the mantle. The temperature of the upper part is low (q is high) but the temperature gradient in the lithosphere is high and temperature is increasing fast. In the mantle below the lithosphere, the temperature gradient is low (could be close to the adiabatic one). The melting temperature is increasing with depth faster than true temperature. Hence, q and the viscosity reach minimum value just below LAB and are increasing with depth in the mantle below. It is a typical situation. The tectonic processes in subduction zones could change this picture. The one lithospheric plate could be placed in the mantle below another plate. Distribution q in such a case could have two minima, so two asthenospheric layers could be formed. Another important factor determining rheological properties is a stress tensor T. Generally viscosity is proportional to the power of the invariant of the stress tensor: I(T)^(1-n). For n=1 the viscosity does not depend on stress (i.e. Newtonian rheology), for true mantle

  3. Evolution of asthenospheric layers as a result of changing stress field

    Czechowski, Leszek; Grad, Marek


    The lithosphere is underlain by the asthenosphere. Traditionally, the boundary between the lithosphere and the asthenosphere (LAB) is defined by a difference in response to stress: the lithosphere remains elastic or brittle, while the asthenosphere deforms viscously and accommodates strain through plastic deformation. The reology of rocks depends on many factors: temperature, pressure, chemical composition, size of grains, etc. However, the basic differences of lithosphere and asthenosphere properties could be explained as a result of the temperature and pressure. The effective viscosity of mantle is proportional to C exp(A q), where q is the ratio (melting temperature/temperature), C and A are positive constants. The mantle is not molten, so q>1. If the temperature is close to the melting temperature then q is close to 1 and effective viscosity is low (e.g. 1018 Pa s). This situation is observed in asthenosphere. The lithosphere is a thermal boundary layer for the convection in the mantle. The temperature of the upper part is low (q is high) but the temperature gradient in the lithosphere is high and temperature is increasing fast. In the mantle below the lithosphere, the temperature gradient is low (could be close to the adiabatic one). The melting temperature is increasing with depth faster than true temperature. Hence, q and the viscosity reach minimum value just below LAB and are increasing with depth in the mantle below. It is a typical situation. The tectonic processes in subduction zones could change this picture. The one lithospheric plate could be placed in the mantle below another plate. Distribution q in such a case could have two minima, so two asthenospheric layers could be formed. Another important factor determining rheological properties is a stress tensor T. Generally viscosity is proportional to the power of the invariant of the stress tensor: I(T)^(1-n). For n=1 the viscosity does not depend on stress (i.e. Newtonian rheology), for true mantle n

  4. 78 FR 78165 - Orders: Reporting by Regulated Entities of Stress Testing Results as of September 30, 2013...


    ... AGENCY 12 CFR Part 1238 Orders: Reporting by Regulated Entities of Stress Testing Results as of September... controls, that their operations and activities foster liquid, efficient, competitive, and resilient... prescribe for the regulated entities the scenarios to be used for stress testing. The Summary Instructions...

  5. Repeated exposure to heat stress results in a diaphragm phenotype that resists ventilator-induced diaphragm dysfunction.

    Yoshihara, Toshinori; Ichinoseki-Sekine, Noriko; Kakigi, Ryo; Tsuzuki, Takamasa; Sugiura, Takao; Powers, Scott K; Naito, Hisashi


    Controlled mechanical ventilation (CMV) is a life-saving intervention for patients in respiratory failure. Unfortunately, prolonged mechanical ventilation (MV) results in diaphragmatic atrophy and contractile dysfunction, both of which are predicted to contribute to problems in weaning patients from the ventilator. Therefore, developing a strategy to protect the diaphragm against ventilator-induced weakness is important. We tested the hypothesis that repeated bouts of heat stress result in diaphragm resistance against CMV-induced atrophy and contractile dysfunction. Male Wistar rats were randomly divided into six experimental groups: 1) control; 2) single bout of whole body heat stress; 3) repeated bouts of whole body heat stress; 4) 12 h CMV; 5) single bout of whole body heat stress 24 h before CMV; and 6) repeated bouts of whole body heat stress 1, 3, and 5 days before 12 h of CMV. Our results revealed that repeated bouts of heat stress resulted in increased levels of heat shock protein 72 in the diaphragm and protection against both CMV-induced diaphragmatic atrophy and contractile dysfunction at submaximal stimulation frequencies. The specific mechanisms responsible for this protection remain unclear: this heat stress-induced protection against CMV-induced diaphragmatic atrophy and weakness may be partially due to reduced diaphragmatic oxidative stress, diminished activation of signal transducer/transcriptional activator-3, lower caspase-3 activation, and decreased autophagy in the diaphragm.

  6. Noise Induce Stress Assessment via Salivary Cortisol Measuring


    Result: On the rest day and work day, between morning salivary cortisol was no significant difference in two groups. Comparing evening cortisol concentrations in work day with rest day a significant difference was observed, in worker group, but it was not significant in the other group. The evening cortisol in the working day in was significantly higher among workers than officers. .Conclusion: This study revealed that industrial noise exposure with levels higher than 80 dBA has a significant effect on salivary cortisol elevation.

  7. Physical Stress may Result in Growth Suppression and Pubertal Delay in Working Boys

    Muhammad Irfan


    Full Text Available Child labour is an immense problem in Pakistan. As labour boys are put under persistent/severe physical stress, we hypothesised, that it may result in higher levels of cortisol and exhaust glycogen, fats and protein. Depletion of fats may result in lower body weight, and insufficient leptin concentrations could excite gonadotropic releasing hormone (GnRH at normal time of puberty in working boys. Moreover, lower testosterone levels in working boys, due to delayed puberty, may result in suppression of somatotropic axis. Short/weak stature and failure of onset of puberty may cause poor performance, inferiority complex and psychological disorders. Therefore, the present study is designed to find out the timing of onset of puberty in working boys. The study will include 10–18 years of working boys as case and non-working boys of the same age group as control. Working boys will be labour boys, while the control group will not be involved in physical work. A questionnaire will be used to record socioeconomic status, major diseases, nutritional status, type and duration of work and family history of puberty, growth and obesity of subjects. Boys with familial history of pubertal delay, obesity, malnutrition, mental disorders, haematological diseases and severe/chronic diseases will be excluded. The intensity of physical working stress will be determined by a grading scale. The anthropometric data including height, weight, body mass index (BMI, bone age and tests of adiposity will be collected from subjects. The stages of pubertal onset will be determined by Tanner staging. Serum concentrations of hormones of growth, thyroid, adrenal, brain–gut and gonadal axis will be determined in non-working and working boys. Physical and hormonal tests of the working boys and the comparison with non-working boys are sufficient to test the idea

  8. Physical Stress May Result in Growth Suppression and Pubertal Delay in Working Boys

    Mazhar Qayyum


    Full Text Available Child labor is an immense problem of Pakistan. As labor boys stay under persistent/severe physical stress, we hypothesized, that it may result in higher levels of cortisol and exhaust glycogen, fats and proteins. Depletion of fats may result in lower body weight, and insufficient leptin concentrations to excite gonadotropic releasing hormone (GnRH at the normal time of puberty in working boys. Moreover, lower testosterone levels in working boys, due to delayed puberty, may result in suppression of somatotropic axis. The Short/weak stature and failure of the onset of puberty may cause poor performance, the inferiority complex and psychological disorders. Therefore, present study is designed to find out timing of onset of the puberty in working boys. The study will include 10-18 years of working boys as a case and non-working boys of same age groups as control. Working boys will be labor boys while the control group will not be involved in physical work. A questionnaire will be used to record socioeconomic status, major diseases, nutritional status, type, and duration of work and family history of puberty, growth and obesity of subjects. Boys with familial history of pubertal delay, obesity, malnutrition, mental disorders, hematological diseases and severe/chronic diseases will be excluded. The intensity of physical working stress will be determined by a grading scale. The anthropometric data including height, weight, body mass index (BMI, bone age, tests of adiposity will be collected from subjects. The stages of pubertal onset will be determined by Tanner staging. Serum concentrations of hormones of growth, thyroid, adrenal, brain-gut and gonadal axis will be determined in nonworking and working boys. Physical and hormonal tests of the working boys and comparison with non-working boys are sufficient to test the idea.

  9. A new nondestructive instrument for bulk residual stress measurement using tungsten kα1 X-ray

    Ma, Ce; Dou, Zuo-yong; Chen, Li; Li, Yun; Tan, Xiao; Dong, Ping; Zhang, Jin; Zheng, Lin; Zhang, Peng-cheng


    We describe an experimental instrument used for measuring nondestructively the residual stress using short wavelength X-ray, tungsten kα1. By introducing a photon energy screening technology, the monochromatic X-ray diffraction of tungsten kα1 was realized using a CdTe detector. A high precision Huber goniometer is utilized in order to reduce the error in residual stress measurement. This paper summarizes the main performance of this instrument, measurement depth, stress error, as opposed to the neutron diffraction measurements of residual stress. Here, we demonstrate an application on the determination of residual stress in an aluminum alloy welded by the friction stir welding.

  10. Stress induced by hooking, net towing, elevated sea water temperature and air in sablefish: Lack of concordance between mortality and physiological measures of stress

    Davis, M.W.; Olla, B.L.; Schreck, C.B.


    In a series of laboratory studies designed to simulate bycatch processes, sablefish Anoplopoma fimbria were either hooked for up to 24 h or towed in a net for 4 h and then subjected to an abrupt transfer to elevated sea water temperature and air. Mortality did not result from hooking or net towing followed by exposure to air, but increased for both capture methods as fish were exposed to elevated temperatures, reflecting the magnifying effect of elevated temperature on mortality. Hooking and exposure to air resulted in increased plasma cortisol and lactate concentrations, while the combination of hooking and exposure to elevated temperature and air resulted in increased lactate and potassium concentrations. In fish that were towed in a net and exposed to air, cortisol, lactate, potassium and sodium concentrations increased, but when subjected to elevated temperature and air, no further increases occurred above the concentrations induced by net towing and air, suggesting a possible maximum of the physiological stress response. The results suggest that caution should be exercised when using physiological measures to quantify stress induced by capture and exposure to elevated temperature and air, that ultimately result in mortality, since the connections between physiological stress and mortality in bycatch processes remain to be fully understood.


    Tarasenko V.I.


    dysfunction and resembles the phenotype of plants with inactivated genes encoding chloroplast proteins. The study of reactive oxygen species (ROS level revealed the significantly elevated superoxide content in the mutant plant leaves. Moreover, the measurement of enzymatic activity of different superoxide dismutase isoforms showed an increased level of CuZnSOD which is localized predominantly in chloroplasts. At the same time, the level of mitochondria-localized MnSOD remained unchanged. This fact also points to chloroplasts as a potential source of increased ROS content in mutant plants. To test this hypothesis, we studied the ROS level in the guard cells of mutant and wild-type plants. As a result, the significant increase of chloroplast-derived ROS content in guard cells of mutant plants was showed. Therefore, we conclude that an inactivation of the RTNLB16 gene leads to severe defects in chloroplast functioning and assotiated oxidative stress. We suppose that RTNLB16 protein participates in interactions between chloroplasts and other intracellular structures.

  12. Contraction stresses in dental composites adjacent to and at the bonded interface as measured by crack analysis.

    Yamamoto, Takatsugu; Nishide, Akihito; Swain, Michael V; Ferracane, Jack L; Sakaguchi, Ronald L; Momoi, Yasuko


    The objective of this study was to calculate stresses produced by polymerization contraction in regions surrounding a dental resin composite restoration. Initial cracks were made with a Vickers indenter at various distances from the edge of a cylindrical hole in a soda-lime glass disk. Indentation crack lengths were measured parallel to tangents to the hole edge. Resin composites (three brands) were placed in the hole and polymerized (two light irradiation protocols) at equal radiation exposures. The crack lengths were re-measured at 2 and 10 min after irradiation. Radial tensile stresses due to polymerization contraction at the location of the cracks (σ(crack)) were calculated from the incremental crack lengths and the fracture toughness K(c) of the glass. Contraction stresses at the composite-glass bonded interface (σ(interface)) were calculated from σ(crack) on the basis of the simple mechanics of an internally pressurized thick-walled cylinder. The greater the distance or the shorter the time following polymerization, the smaller was σ(crack). Distance, material, irradiation protocol and time significantly affected σ(crack). Two-step irradiation resulted in a significant reduction in the magnitude of σ(interface) for all resin composites. The contraction stress in soda-lime glass propagated indentation cracks at various distances from the cavity, enabling calculation of the contraction stresses.

  13. Flexural Capability of Patterned Transparent Conductive Substrate by Performing Electrical Measurements and Stress Simulations

    Chang-Chun Lee


    Full Text Available The suitability of stacked thin films for next-generation display technology was analyzed based on their properties and geometrical designs to evaluate the mechanical reliability of transparent conducting thin films utilized in flexural displays. In general, the high bending stress induced by various operation conditions is a major concern regarding the mechanical reliability of indium–tin–oxide (ITO films deposited on polyethylene terephthalate (PET substrates; mechanical reliability is commonly used to estimate the flexibility of displays. However, the pattern effect is rarely investigated to estimate the mechanical reliability of ITO/PET films. Thus, this study examined the flexible content of patterned ITO/PET films with two different line widths by conducting bending tests and sheet resistance measurements. Moreover, a stress–strain simulation enabled by finite element analysis was performed on the patterned ITO/PET to explore the stress impact of stacked film structures under various levels of flexural load. Results show that the design of the ITO/PET film can be applied in developing mechanically reliable flexible electronics.

  14. Standard test method for calibration of surface/stress measuring devices

    American Society for Testing and Materials. Philadelphia


    Return to Contents page 1.1 This test method covers calibration or verification of calibration, or both, of surface-stress measuring devices used to measure stress in annealed and heat-strengthened or tempered glass using polariscopic or refractometry based principles. 1.2 This test method is nondestructive. 1.3 This test method uses transmitted light, and therefore, is applicable to light-transmitting glasses. 1.4 This test method is not applicable to chemically tempered glass. 1.5 Using the procedure described, surface stresses can be measured only on the “tin” side of float glass. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  15. On Calculation Methods and Results for Straight Cylindrical Roller Bearing Deflection, Stiffness, and Stress

    Krantz, Timothy L.


    The purpose of this study was to assess some calculation methods for quantifying the relationships of bearing geometry, material properties, load, deflection, stiffness, and stress. The scope of the work was limited to two-dimensional modeling of straight cylindrical roller bearings. Preparations for studies of dynamic response of bearings with damaged surfaces motivated this work. Studies were selected to exercise and build confidence in the numerical tools. Three calculation methods were used in this work. Two of the methods were numerical solutions of the Hertz contact approach. The third method used was a combined finite element surface integral method. Example calculations were done for a single roller loaded between an inner and outer raceway for code verification. Next, a bearing with 13 rollers and all-steel construction was used as an example to do additional code verification, including an assessment of the leading order of accuracy of the finite element and surface integral method. Results from that study show that the method is at least first-order accurate. Those results also show that the contact grid refinement has a more significant influence on precision as compared to the finite element grid refinement. To explore the influence of material properties, the 13-roller bearing was modeled as made from Nitinol 60, a material with very different properties from steel and showing some potential for bearing applications. The codes were exercised to compare contact areas and stress levels for steel and Nitinol 60 bearings operating at equivalent power density. As a step toward modeling the dynamic response of bearings having surface damage, static analyses were completed to simulate a bearing with a spall or similar damage.

  16. Getting Results in Housing: A Framework for Monitoring Results in Housing Projects: Using Measurable Indicators

    Shlomo Angel; Michael Jacobs


    The aim of this paper is to help project teams develop results indicators for housing projects. These indicators are intended, primarily, as an instrument for managing projects and should help staff in the country offices, in headquarters and in executing agencies to identify the components of a project that are working as intended, and the ones that may need attention to keep the project on track. Additionally, the indicators can provide a foundation for project evaluations, at the mid-term ...

  17. Rock stress measurements. Preparatory stage of the equipment development project; Kallioperaen jaennitystilan mittaaminen. Laitekehityshankkeen valmisteluvaihe

    Mononen, S.; Hakala, M.; Mikkola, P


    In recent years the rock stress measurement methods used in Finland have been overcoring and hydraulic fracturing. There have been mainly two companies involved in these measurements, namely Suomen Malmi Oy (Smoy) and SwedPower AB. Smoy has done measurements for mines and for rock engineering projects, whereas SwedPower AB has mainly been involved in nuclear waste disposal investigations and conducted hydraulic fracturing measurements in deep boreholes. Smoy together with its partners started in February 2001 a project named JTM, which was a preliminary stage for a future project, which aims to develop a device most suitable for rock stress measurements in Finland. The partners in the project were HUT Rock Engineering, Posiva Oy, Saanio and Riekkola Oy, Gridpoint Finland Oy and Geopros Oy. Tekes, the National Technology Agency, provided almost half of the project funding. In the management group of the project were Pekka Mikkola (chairman) and Tero Laurila from Smoy, Pekka Saerkkae and Sakari Mononen (full-time researcher) from HUT, Aimo Hautojaervi (Posiva Oy), Erik Johansson (Saanio and Riekkola Oy), Matti Hakala (Gridpoint Finland Oy) and Heikki Haemaelaeinen (Geopros Oy). The aim of the JTM-project was to find out the needs for the development of a device most suitable for rock stress measurements in Finnish mines and rock engineering projects. During the project work was done to find out the range of rock stress measurement devices available, to find out the needs for measurements, and to get acquainted to the measurements done in Scandinavia. Also a report of the most suitable methods for Finnish rock conditions was done based on literature and on interviews of rock stress experts. Based on all the information collected during the project a clear picture of the needs for rock stress measurements in Finland could be formed and a preliminary plan of a future project was done. The aim of the suggested project is to build a device based on hydraulic fracturing

  18. A Method Using Optical Contactless Displacement Sensors to Measure Vibration Stress of Small-Bore Piping.

    Maekawa, Akira; Tsuji, Takashi; Takahashi, Tsuneo; Noda, Michiyasu


    In nuclear power plants, vibration stress of piping is frequently evaluated to prevent fatigue failure. A simple and fast measurement method is attractive to evaluate many piping systems efficiently. In this study, a method to measure the vibration stress using optical contactless displacement sensors was proposed, the prototype instrument was developed, and the instrument practicality for the method was verified. In the proposed method, light emitting diodes (LEDs) were used as measurement sensors and the vibration stress was estimated by measuring the deformation geometry of the piping caused by oscillation, which was measured as the piping curvature radius. The method provided fast and simple vibration estimates for small-bore piping. Its verification and practicality were confirmed by vibration tests using a test pipe and mock-up piping. The stress measured by both the proposed method and an accurate conventional method using strain gauges were in agreement, and it was concluded that the proposed method could be used for actual plant piping systems.

  19. Measured Results

    Wiley, Frank N.


    Teachers have the "germiest" jobs in America. Only one professional can do anything about getting rid of germs once they have infected buildings: the school custodian. Custodians should be the first line of defense against pathogens in schools. Unfortunately, most are not trained or equipped to deal with this invisible world. Facility maintenance…

  20. Studies of residual stress measurement and analysis techniques for a PWR dissimilar weld joint

    Ogawa, Naoki, E-mail: [Mitsubishi Heavy Industries, Ltd., 2-1-1, Shinhama, Arai-cho, Takasago 676-8686 (Japan); Muroya, Itaru; Iwamoto, Youichi; Ohta, Takahiro; Ochi, Mayumi; Hojo, Kiminobu [Mitsubishi Heavy Industries, Ltd., 2-1-1, Shinhama, Arai-cho, Takasago 676-8686 (Japan); Ogawa, Kazuo [Japan Nuclear Energy Safety Organization, 3-17-1, Toranomon, Minato-ku, Tokyo 105-0001 (Japan)


    For evaluation of the PWSCC crack propagation behavior, a test model was produced using the same fabrication process of Japanese PWR plants and the stress distribution change was measured during a fabrication process such as a hydrostatic test, welding a main coolant pipe to the stainless steel safe end and an operation condition test. For confirmation of validity of the numerical estimation method of the stress distribution, FE analysis was performed to calculate the stress distributions for each fabrication process. From the validation procedure, a standard residual stress evaluation method was established. Furthermore for consideration of characteristics of PWSCC's propagation behavior of the dissimilar welding joint of the safe end nozzles, the influence coefficients at the deepest point for the stress intensity factors of axial cracks with large aspect ratio a/c (crack depth/half of surface crack length) was prepared. The crack shape was assumed a rectangular shape and the stress intensity factors at the deepest point of the crack were calculated with change of crack depth using FE analysis. By using these stress distribution and influence coefficients, a behavior of a PWSCC crack propagation at the safe end nozzles can be estimated easily and rationally.

  1. Effect of normal stresses on the results of thermoplastic mold filling simulation

    Bakharev Alexander


    Full Text Available The paper deals with the effect of the normal stresses on the predicted flow front during the filling stage of thermoplastic injection molding. The normal stresses are predicted using the non-linear Criminale-Ericksen-Filbey model (a variant of the second-order fluid rheological model with viscosity, first and second normal stress coefficients dependent upon magnitude of shear rate incorporated into a comprehensive 3D simulation software for mold-filling analysis. The additional stress term allows the prediction of the so called ear-flow effect (melt racing on the edges of the cavity.

  2. The conformity of BPP and vibroacoustic stimulation results in fetal non reactive non stress test

    M. Modarres


    Full Text Available Background: The most frequently used test for evaluation of fetal health is the Non Stress Test (NST. Unfortunately it has a high incidence of false positive results. The combination of vibroacoustic stimulation with the NTS has been shown to reduce non reactive results. Methods: A tests assessment method was chosen with a simple randomized sampling. 40 pregnant women with non reactive NST in the first 20 minutes who received VAS in one of Tehran University's Hospitals were compared with BPP scores. A vibroacoustic stimulation was applied for a 3 seconds on the maternal abdomen and fallowed within 10 minutes.Data collection tools were NST, sonography instruments ,NST result paper, tooth brusher, watch, demographic questioner and check list. Data analysis was made by descriptive static and by using the Fisher's Exact Test (with level of significant at p<0/05. All statistical analysis were performed using an spss/win. Results: After VAS, 70% of non reactive tracing became reactive. All cases with fetal reactivity response after a VAS had a subsequent BPP score of 8 (negative predictive value of 100%. False positivity of VAS was lower than NST. Conclusion: VAS offers benefits, by decreasing the incidence of non reactive test and reducing test time. VAS lowers the rate of false positive NST. VAS is safe and allows more efficient of prenatal services. This test could be used as a rapid antepartum test to predict fetal well-being.

  3. Measurement of 3-D hydraulic conductivity in aquifer cores at in situ effective stresses.

    Wright, Martin; Dillon, Peter; Pavelic, Paul; Peter, Paul; Nefiodovas, Andrew


    An innovative and nondestructive method to measure the hydraulic conductivity of drill core samples in horizontal and vertical directions within a triaxial cell has been developed. This has been applied to characterizing anisotropy and heterogeneity of a confined consolidated limestone aquifer. Most of the cores tested were isotropic, but hydraulic conductivity varied considerably and the core samples with lowest values were also the most anisotropic. Hydraulic conductivity decreased with increasing effective stress due to closure of microfractures caused by sampling for all core samples. This demonstrates the importance of replicating in situ effective stresses when measuring hydraulic conductivity of cores of deep aquifers in the laboratory.

  4. Neutron measurements of stresses in a test artifact produced by laser-based additive manufacturing

    Gnäupel-Herold, Thomas; Slotwinski, John; Moylan, Shawn


    A stainless steel test artifact produced by Direct Metal Laser Sintering and similar to a proposed standardized test artifact was examined using neutron diffraction. The artifact contained a number of structures with different aspect ratios pertaining to wall thickness, height above base plate, and side length. Through spatial resolutions of the order of one millimeter the volumetric distribution of stresses in several was measured. It was found that the stresses peak in the tensile region around 500 MPa near the top surface, with balancing compressive stresses in the interior. The presence of a support structure (a one millimeter high, thin walled, hence weaker, lattice structure deposited on the base plate, followed by a fully dense AM structure) has only minor effects on the stresses.

  5. Hair Measurements of Cortisol, DHEA, and DHEA to Cortisol Ratio as Biomarkers of Chronic Stress among People Living with HIV in China: Known-Group Validation

    Li, Xiaoming; Zilioli, Samuele; Chen, Zheng; Deng, Huihua; Pan, Juxian


    Background Existing literature suggests that endocrine measures, including the steroid hormones of cortisol and Dehydroepiandrosterone (DHEA), as well as the DHEA to cortisol ratio in the human hair can be used as promising biomarkers of chronic stress among humans. However, data are limited regarding the validity of these measures as biomarkers of chronic stress among people living with HIV (PLWH), whose endocrine system or hypothalamic pituitary adrenal (HPA) axis may be affected by HIV infection and/or antiretroviral therapy (ART) medications. Method Using hair sample data and self-reported survey from 60 PLWH in China, we examined the validity of three endocrine measures among Chinese PLWH using a known-groups validation strategy. High-stress group (n = 30) and low-stress group (n = 30) of PLWH were recruited through individual assessment interviews by a local licensed psychologist. The endocrine measures in hair were extracted and assessed by LC-APCI-MS/MS method. Both bivariate and multivariate analyses were conducted to examine the associations between the endocrine measures and the stress level, and to investigate if the associations differ by ART status. Results The levels of endocrine measures among Chinese PLWH were consistent with existing studies among PLWH. Generally, this pilot study confirmed the association between endocrine measures and chronic stress. The high stress group showed higher level hair cortisol and lower DHEA to cortisol ratio. The higher stress group also reported higher scores of stressful life events, perceived stress, anxiety and depression. Hair cortisol level was positively related to anxiety; DHEA was negatively associated with stressful life events; and the DHEA to cortisol ratio was positively related to stressful life events and perceived stress. ART did not affect the associations between the endocrine measures and stress level. Conclusions Our findings suggest that hair cortisol and DHEA to cortisol ratio can be used as

  6. Local wall shear stress measurements with a thin plate submerged in the sublayer in wall turbulent flows

    Hua, Dan; Suzuki, Hiroki; Mochizuki, Shinsuke


    A local wall shear stress measurement technique has been developed using a thin plate, referred to as a sublayer plate which is attached to the wall in the sublayer of a near-wall turbulent flow. The pressure difference between the leading and trailing edges of the plate is correlated to the known wall shear stress obtained in the fully developed turbulent channel flow. The universal calibration curve can be well represented in dimensionless form, and the sensitivity of the proposed method is as high as that of the sublayer fence, even if the sublayer fence is enveloped by the linear sublayer. The results of additional experiments prove that the sublayer plate has fairly good angular resolution in detecting the direction of the local wall shear stress vector.

  7. Measurement of residual stresses in a multi-pass low alloy ferritic steel weld using X-ray diffraction

    McDonald, E.J.; Exworthy, L.F.; Flewitt, P.E.J. [Magnox Generation, Berkeley (United Kingdom); Hallam, K. [Interface Analysis Centre, Univ. of Bristol (United Kingdom); Bell, W. [Mitsui Babcock Energy Ltd, Renfrew (United Kingdom)


    A trial part through-section excavation manual metal arc repair weld, designed with a view to minimising residual stresses, was prepared by using a critical combination of weld metal strength, bead size and deposition pattern. The repair was in a low alloy ferritic CrMoV steel plate, and the weldment was made using a lower strength C-Mn steel weld metal. Residual stresses have been measured to a high spatial resolution, 1.5 mm, across the weldment using the X-ray diffraction technique with Cr K{alpha} X-radiation. Peak tensile stresses have been identified in the heat affected zone in the parent plate adjacent to the weld metal. Further measurements have been made using the rosette strain gauge centre hole relaxation and deep hole drilling techniques. Results from the experimental techniques are compared and the measured residual stress profiles are discussed with respect to the predictions of a finite element model for this particular multi-pass repair weld. (orig.)

  8. The measurement of shear stress and total heat flux in a nonadiabatic turbulent hypersonic boundary layer

    Mikulla, V.; Horstman, C. C.


    Turbulent shear stress and direct turbulent total heat-flux measurements have been made across a nonadiabatic, zero pressure gradient, hypersonic boundary layer by using specially designed hot-wire probes free of strain-gauging and wire oscillation. Heat-flux measurements were in reasonably good agreement with values obtained by integrating the energy equation using measured profiles of velocity and temperature. The shear-stress values deduced from the measurements, by assuming zero correlation of velocity and pressure fluctuations, were lower than the values obtained by integrating the momentum equation. Statistical properties of the cross-correlations are similar to corresponding incompressible measurements at approximately the same momentum-thickness Reynolds number.

  9. Measurement and prediction of residual stress in a bead-on-plate weld benchmark specimen

    Ficquet, X.; Smith, D.J. [Department of Mechanical Engineering, University of Bristol, Queen' s Building, University Walk, Bristol BS8 1TR (United Kingdom); Truman, C.E. [Department of Mechanical Engineering, University of Bristol, Queen' s Building, University Walk, Bristol BS8 1TR (United Kingdom)], E-mail:; Kingston, E.J. [Veqter Ltd, University Gate East, Park Row, Bristol BS1 5UB (United Kingdom); Dennis, R.J. [Frazer-Nash Consultancy Limited, 1 Trinity Street, College Green, Bristol BS1 5TE (United Kingdom)


    This paper presents measurements and predictions of the residual stresses generated by laying a single weld bead on a flat, austenitic stainless steel plate. The residual stress field that is created is strongly three-dimensional and is considered representative of that found in a repair weld. Through-thickness measurements are made using the deep hole drilling technique, and near-surface measurements are made using incremental centre hole drilling. Measurements are compared to predictions at the same locations made using finite element analysis incorporating an advanced, non-linear kinematic hardening model. The work was conducted as part of an European round robin exercise, coordinated as part of the NeT network. Overall, there was broad agreement between measurements and predictions, but there were notable differences.

  10. Measurement of the state of stress in silicon with micro-Raman spectroscopy

    Harris, Stephen J.; O'Neill, Ann E.; Yang, Wen; Gustafson, Peter; Boileau, James; Weber, W. H.; Majumdar, Bhaskar; Ghosh, Somnath


    Micro-Raman spectroscopy has been widely used to measure local stresses in silicon and other cubic materials. However, a single (scalar) line position measurement cannot determine the complete stress state unless it has a very simple form such as uniaxial. Previously published micro-Raman strategies designed to determine additional elements of the stress tensor take advantage of the polarization and intensity of the Raman-scattered light, but these strategies have not been validated experimentally. In this work, we test one such stategy [S. Narayanan, S. Kalidindi, and L. Schadler, J. Appl. Phys. 82, 2595 (1997)] for rectangular (110)- and (111)-orientated silicon wafers. The wafers are subjected to a bending stress using a custom-designed apparatus, and the state of (plane) stress is modeled with ABAQUS. The Raman shifts are calculated using previously published values for silicon phonon deformation potentials. The experimentally measured values for σxx, σyy, and τxy at the silicon surface are in good agreement with those calculated with the ABAQUS model.

  11. Measurement of the Full State of Stress of Silicon with Micro-Raman Spectroscopy

    Harris, Stephen; Weber, W. H.; Majumdar, Bhaskar; Ghosh, Somnath


    Micro-Raman spectroscopy has been widely used to measure local stresses in silicon and other cubic materials. However, a single (scalar) line position measurement cannot determine the complete stress state unless it is has a very simple form, such as uniaxial. Previously published micro-Raman strategies designed to determine additional elements of the stress tensor take advantage of the polarization and intensity of the Raman scattered light, but these strategies have not been validated experimentally. In this work we test one such stategy [S. Narayanan, S. Kalidindi, and L. Schadler, JAP. 82, 2595 (1997)] for rectangular (110)- and (111)-orientated silicon wafers. The wafers are subjected to a bending stress, and the state of (plane) stress is modeled with ABAQUS. The Raman shifts, intensities, and polarizations are calculated using previously published values for silicon phonon deformation potentials. The experimentally measured values for σxx, σyy, and τxy at the silicon surface are in good agreement with those calculated with the ABAQUS model.

  12. Objective measures of right ventricular function during exercise: results of a pilot study.

    Anjak, Ahmad; López-Candales, Angel; Lopez, Francisco R; Harris, David; Elwing, Jean


    A growing body of evidence seems to suggest that reduction in right ventricular (RV) systolic function is not only associated with both development of symptoms associated with pulmonary arterial hypertension (PAH) but also increased morbidity and adverse clinical outcomes. Recent data suggest that supine bicycle stress echocardiography (sBEE) is feasible and provides realistic resistance and compliance estimations. The study design was a retrospective analysis of sBEE obtained for clinical indications of dyspnea on exertion or unexplained exercise intolerance. A total of 30 sBEE studies were included. The first 10 sBEE studies served as a calibration cohort not only to establish objective measures of RV performance but also to determine feasibility and reproducibility. The following 20 sBEE served as a validation cohort. Our results demonstrate that tricuspid annular plane systolic excursion and tricuspid annular systolic velocity, even when measured by an untrained reader, are reliable and accurate measures of the RV response to exercise during a sBEE protocol. Furthermore, measurements of RV myocardial performance (Tei index) or peak RV strain during exercise not only are time consuming but also simply unreliable and should not be utilized to evaluate RV function during sBEE. The results of our pilot study suggest that sBEE might be promising for detecting RV abnormalities during exercise. A larger prospective study is now needed to determine if TAPSE and tricuspid annular systolic velocity recorded during sBEE might be useful in assessing patients presenting with dyspnea during exercise or suspected of having PAH. © 2013, Wiley Periodicals, Inc.

  13. Unconscious fearful priming followed by a psychosocial stress test results in higher cortisol levels.

    Hänsel, Alexander; von Känel, Roland


    Human perception of stress includes an automatic pathway that processes subliminal presented stimuli below the threshold of conscious awareness. Subliminal stimuli can therefore activate the physiologic stress system. Unconscious emotional signals were shown to significantly moderate reactions and responses to subsequent stimuli, an effect called 'priming'. We hypothesized that subliminal presentation of a fearful signal during the Stroop task compared with an emotionally neutral one will prime stress reactivity in a subsequently applied psychosocial stress task, thereby yielding a significant increase in salivary cortisol. Half of 36 participants were repeatedly presented either a fearful face or a neutral one. After this, all underwent a psychosocial stress task. The fearful group showed a significant increase in cortisol levels (p = 0.022). This change was not affected by sex, age and body mass index, and it also did not change when taking resting cortisol levels into account. Post-hoc analyses showed that the increase in cortisol in the fearful group started immediately after the psychosocial stress test. Hence, subliminal exposure to a fearful signal in combination with the Stroop and followed by a psychosocial stress test leads to an increase in stress reactivity.

  14. Cognitive Processing Therapy for Acute Stress Disorder Resulting from an Anti-Gay Assault

    Kaysen, Debra; Lostutter, Ty W.; Goines, Marie A.


    This case study describes Cognitive Processing Therapy (CPT) with a 30-year-old gay man with symptoms of acute stress disorder (ASD) following a recent homophobic assault. Treatment addressed assault-related posttraumatic stress disorder symptoms and depressive symptoms. Also addressed were low self-esteem, helplessness, and high degrees of…

  15. Tripod sigma : results of a pro-active work-stress survey

    Nelemans, R.; Wiezer, N.; Vaas, F.; Gort, J.; Groeneweg, J.


    Work related stress is an important causes of disability and absenteeism. TNO Work and Employment has developed an instrument, called Tripod Sigma, that identifies risks to work stress and provides tools for remedying these risks. The Tripod Sigma model is developed analogous to the Tripod philosoph

  16. Stress urinary incontinence and posterior bladder suspension defects. Results of vaginal repair versus Burch colposuspension

    Thunedborg, P; Fischer-Rasmussen, W; Jensen, S B


    Vaginal repair has been recommended in cases of stress urinary incontinence and posterior bladder suspension defect diagnosed by colpocysto-urethrography. Thirty-eight women with stress urinary incontinence and posterior suspension defect have been treated. First, 19 women underwent a vaginal rep...

  17. Tripod sigma: results of a pro-active work stress-survey

    Nelemans, R.; Wiezer, N.; Vaas, F.; Gort, J.; Groeneweg, J.


    Work related stress is an important causes of disability and absenteeism. TNO Work and Employment has developed an instrument, called Tripod Sigma, that identifies risks to work stress and provides tools for remedying these risks. The Tripod Sigma model is developed analogous to the Tripod

  18. Method of stress and measurement modes for research of thin dielectric films of MIS structures

    Andreev, Vladimir V.; Maslovsky, Vladimir M.; Andreev, Dmitrii V.; Stolyarov, Alexander A.


    The paper proposes a new method of stress and measurement modes for research of thin dielectric films of MIS structures. The method realizes injection of the most part of charge into gate dielectric in one of stress modes: either current owing through dielectric is constant or voltage applied to gate is constant. In order to acquire an additional information about changing of charge state of MIS structure, the stress condition is interrupted in certain time ranges and during these time ranges the mode, in which structure is, is the mode of measurement. In measurement mode, changing of electric fields at interfaces between dielectric and semiconductor is monitored. By using these data, density of charge, which is accumulated in gate dielectric, and its centroid are calculated. Besides, by using these data, one studies processes of generation and relaxation of charge in dielectric. In order to raise precision of the method and reduce an influence of switching effects in measurement mode, density of measurement current should be much lower than density of stress current.

  19. Physiological Consequences of Genetic Transformation: Result of Target Gene Expression or Stress Reaction?

    A.G. Enikeev


    Full Text Available The transgenic and non-transgenic tobacco cell cultures were analyzed for resistance to abiotic and biotic stress. The different physiological reaction of cell culture depending on T-DNA structure (or transgen structure was observed. The cell culture transformed by disarmed Agrobacterium tumefaciense A699 with pCNL 65 nptII demonstrated the same stress-resistance as non-transgenic control cell culture. The cell culture transformed by Agrobacterium tumefaciense LBA 4400 pBiCaMV nptII + hsp101 showed a raised stress-resistance to high temperature, high KF concentration, and to the action of Clavibacter michiganensis ssp sepidonicus. Obviously, the expression of transferred arabodopsis gene hsp101 provides protection properties of transgenic cell culture under the influence of various stress factors. Moreover, that agrobacterial transformation as previous stress-factor is supposed to make a contribution to formation of transgenic cell culture cross-resistance.

  20. Combined heart rate variability and dynamic measures for quantitatively characterizing the cardiac stress status during cycling exercise.

    Chen, Szi-Wen; Liaw, Jiunn-Woei; Chang, Ya-Ju; Chuang, Li-Ling; Chien, Chun-Tse


    In this study, we aimed to seek for different ways of measuring cardiac stress in terms of heart rate variability (HRV) and heart rate (HR) dynamics, and to develop a novel index that can effectively summarize the information reflected by these measures to continuously and quantitatively characterize the cardiac stress status during physical exercise. Standard deviation, spectral measure of HRV as well as a nonlinear detrended fluctuation analysis (DFA) based fractal-like behavior measure of HR dynamics were all evaluated on the RR time series derived from windowed electrocardiogram (ECG) data for the subjects undergoing cycling exercise. We recruited eleven young healthy subjects in our tests. Each subject was asked to maintain a fixed speed under a constant load during the pedaling test. We obtained the running estimates of the standard deviation of the normal-to-normal interval (SDNN), the high-fidelity power spectral density (PSD) of HRV, and the DFA scaling exponent α, respectively. A trend analysis and a multivariate linear regression analysis of these measures were then performed. Numerical experimental results produced by our analyses showed that a decrease in both SDNN and α was seen during the cycling exercise, while there was no significant correlation between the standard lower frequency to higher frequency (LF-to-HF) spectral power ratio of HRV and the exercise intensity. In addition, while the SDNN and α were both negatively correlated with the Borg rating of perceived exertion (RPE) scale value, it seemed that the LF-to-HF power ratio might not have substantial impact on the Borg value, suggesting that the SDNN and α may be further used as features to detect the cardiac stress status during the physical exercise. We further approached this detection problem by applying a linear discriminant analysis (LDA) to both feature candidates for the task of cardiac stress stratification. As a result, a time-varying parameter, referred to as the cardiac

  1. Finite Element Modeling of the Bulk Magnitization of Railroad Wheels to Improve Test Conditions for Magnetoacoustic Residual Stress Measurements

    Fulton, J. P.; Wincheski, B.; Namkung, M.; Utrata, D.


    The magnetoacoustic measurement technique has been used successfully for residual stress measurements in laboratory samples. However, when used to field test samples with complex geometries, such as railroad wheels, the sensitivity of the method declines dramatically. It has been suggested that the decrease in performance may be due, in part, to an insufficient or nonuniform magnetic induction in the test sample. The purpose of this paper is to optimize the test conditions by using finite element modeling to predict the distribution of the induced bulk magnetization of railroad wheels. The results suggest that it is possible to obtain a sufficiently large and uniform bulk magnetization by altering the shape of the electromagnet used in the tests. Consequently, problems associated with bulk magnetization can be overcome, and should not prohibit the magnetoacoustic technique from being used to make residual stress measurements in railroad wheels. We begin by giving a brief overview of the magnetoacoustic technique as it applies to residual stress measurements of railroad wheels. We then define the finite element model used to predict the behavior of the current test configuration along with the nonlinear constitutive relations which we obtained experimentally through measurements on materials typically used to construct both railroad wheels and electromagnets. Finally, we show that by modifying the pole of the electromagnet it is possible to obtain a significantly more uniform bulk magnetization in the region of interest.

  2. Confocal detection of Rayleigh scattering for residual stress measurement in chemically tempered glass

    Hödemann, S.; Möls, P.; Kiisk, V.; Murata, T.; Saar, R.; Kikas, J.


    A new optical method is presented for evaluation of the stress profile in chemically tempered (chemically strengthened) glass based on confocal detection of scattered laser beam. Theoretically, a lateral resolution of 0.2 μm and a depth resolution of 0.6 μm could be achieved by using a confocal microscope with high-NA immersion objective. The stress profile in the 250 μm thick surface layer of chemically tempered lithium aluminosilicate glass was measured with a high spatial resolution to illustrate the capability of the method. The confocal method is validated using transmission photoelastic and Na+ ion concentration profile measurement. Compositional influence on the stress-optic coefficient is calculated and discussed. Our method opens up new possibilities for three-dimensional scattered light tomography of mechanical imaging in birefringent materials.

  3. Confocal detection of Rayleigh scattering for residual stress measurement in chemically tempered glass

    Hödemann, S., E-mail:; Möls, P.; Kiisk, V.; Saar, R.; Kikas, J. [Institute of Physics, University of Tartu, Wilhelm Ostwald st., Tartu 50411 (Estonia); Murata, T. [Nippon Electric Glass Co., 7-1 Seiran 2-chome, Otsu-shi, Shiga 520-8639 (Japan)


    A new optical method is presented for evaluation of the stress profile in chemically tempered (chemically strengthened) glass based on confocal detection of scattered laser beam. Theoretically, a lateral resolution of 0.2 μm and a depth resolution of 0.6 μm could be achieved by using a confocal microscope with high-NA immersion objective. The stress profile in the 250 μm thick surface layer of chemically tempered lithium aluminosilicate glass was measured with a high spatial resolution to illustrate the capability of the method. The confocal method is validated using transmission photoelastic and Na{sup +} ion concentration profile measurement. Compositional influence on the stress-optic coefficient is calculated and discussed. Our method opens up new possibilities for three-dimensional scattered light tomography of mechanical imaging in birefringent materials.

  4. Urinary oxidative stress biomarkers among local residents measured 6years after the Hebei Spirit oil spill.

    Kim, Jung-Ah; Noh, Su Ryeon; Cheong, Hae-Kwan; Ha, Mina; Eom, Sang-Yong; Kim, Heon; Park, Myung-Sook; Chu, Yeonhee; Lee, Seung-Hwa; Choi, Kyungho


    In December 2007, the Hebei Spirit oil spill occurred on the west coast of South Korea. Association between crude oil exposure and the levels of urinary oxidative stress biomarkers was reported among the local residents, 1.5years after the accident. The aim of this study was to follow-up possible longer-term effects of the oil spill among the residents near the oil spill. Six years after the accident, urinary oxidative stress biomarkers of the residents were associated with surrogates of oil exposure. The target subjects were divided into two groups based on the distance of their residence to the spill site, i.e., those near the spill site ('Near' group, n=476), and those far from the spill ('Far' group, n=152). A questionnaire was administered by trained interviewers or self-reporting, and demographic information and other parameters of the participants, such as socioeconomic status, smoking and drinking behaviors, disease history, and duration of clean-up activities after the spill, were collected. The participants' levels of 8-hydroxy-2-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) in 12 h urine samples were measured as indicators of oxidative DNA damage and lipid peroxidation, respectively. A general linear model was used for statistical analysis. Urinary MDA and 8-OHdG levels measured from 'Near' group, i.e., geometric mean of 2.19μmol/g creatinine, and 5.41μg/g creatinine, respectively, were higher than those of 'Far' group. Especially, urinary 8-OHdG levels in the 'Near' group were significantly higher than those of 'Far' after adjusting relevant covariates. In addition, the duration of clean-up activities showed a significant association with both urinary 8-OHdG and MDA levels. Even 6years after the oil spill, positive associations between oxidative stress biomarkers and surrogates of oil exposure were evident. While the present study design lacks biomarkers of exposure, the results of this study suggest that the consequences of oil pollution may last

  5. An exploration of measures for comparing measurements with the results from meteorological models for Mexico City

    Williams, M.D.; Brown, M.J.


    Los Alamos National Laboratory and Instituto Mexicano del Petroleo have completed a joint study of options for improving air quality in Mexico City. We used a three-dimensional, prognostic, higher-order turbulence model for atmospheric circulation (HOTMAC) to treat domains that include an urbanized area. We tested the model against routine measurements and those of a major field program. During the field program, measurements included: (1) lidar measurements of aerosol transport and dispersion, (2) aircraft measurements of winds, turbulence, and chemical species aloft, (3) aircraft measurements of skin temperatures, and (4) Tethersonde measurements of winds and ozone. We made both graphical and statistical comparisons and we have reported some of the comparisons to provide insight into the meaning of statistical parameters including the index of agreement.

  6. Rock stress orientation measurements using induced thermal spalling in slim boreholes

    Hakami, Eva [Geosigma AB, Uppsala (Sweden)


    In the planning and design of a future underground storage for nuclear waste based on the KBS-3 method, one of the aims is to optimize the layout of deposition tunnels such that the rock stresses on the boundaries of deposition holes are minimized. Previous experiences from heating of larger scale boreholes at the Aespoe Hard Rock Laboratory (AHRL) gave rise to the idea that induced borehole breakouts using thermal loading in smaller diameter boreholes, could be a possible way of determining the stress orientation. Two pilot experiments were performed, one at the Aespoe Hard Rock Laboratory and one at ONKALO research site in Finland. An acoustic televiewer logger was used to measure the detailed geometrical condition of the borehole before and after heating periods. The acoustic televiewer gives a value for each 0.7 mm large pixel size around the borehole periphery. The results from the loggers are presented as images of the borehole wall, and as curves for the maximum, mean and minimum values at each depth. Any changes in the borehole wall geometry may thus be easily detected by comparisons of the logging result images. In addition, using an optical borehole televiewer a good and detailed realistic colour picture of the borehole wall is obtained. From these images the character of the spalls identified may be evaluated further. The heating was performed in a 4 m long section, using a heating cable centred in an 8 m deep vertical borehole, drilled from the floor of the tunnels. For the borehole in the Q-tunnel of AHRL the results from the loggings of the borehole before the heating revealed that breakouts existed even before this pilot test due to previous heating experiments at the site (CAPS). Quite consistent orientation and the typical shape of small breakouts were observed. After the heating the spalling increased slightly at the same locations and a new spalling location also developed at a deeper location in the borehole. At ONKALO three very small changes

  7. Measured Resolved Shear Stresses and Bishop Hill Stress States in Individual Grains of Austenitic Stainless Steel (Postprint)


    Activation of a slip system requires that it is critically stressed , i.e. that the shear stress resolved on the slip system exceeds a threshold...increment. A direct way of investigating which slip systemsmay be active in each grain is to investigate the stress state of the grain. From...correlation (DIC) system [29] and a load cell. The stress - strain curve in Fig. 1b) presents the maximum stress reading after each loading step. Relaxation

  8. [Measurement method of arterial shear stress of rats model based on ultrasonic particle imaging velocimetry].

    Xhu, Yiheng; Qian, Ming; Niu, Lili; Zheng, Hairong; Lu, Guangwen


    The development and progression of atherosclerosis and thrombosis are closely related to changes of hemodynamics parameters. Ultrasonic pulse wave Doppler technique is normally used for noninvasively blood flow imaging. However, this technique only provides one-dimensional velocity and depends on the angle between the ultrasound beam and the local velocity vector. In this study, ultrasonic particle image velocimetry method was used to assess whole field hemodynamic changes in normal blood vessels. By using the polynomial fitting method, we investigated the velocity gradient and assessed the shear in different blood flow velocity of 10 healthy rats. It was found that using four polynomial fitting could result in optimal measurement results. The results obtained by ultrasonic particle image velocimetry accorded with the results obtained using Doppler technique. The statistical average of cyclical vessel wall shear stress was positively related to the locational mean velocity. It is proven that ultrasonic particle image velocimetry method could be used to assess directly the real-time whole field hemodynamic changes in blood vessels and was non-invasively, and should be a good prosperous technique for monitoring complex blood flow in stenotic ar- teries.

  9. Review of magnetoacoustic residual stress measurement technique for iron-like ferromagnetic alloys

    Namkung, M.; Utrata, D.; Langlois, P.; Kushnick, P. W.; Grainger, J. L.


    It is shown that the elastic moduli of ironlike ferromagnetics depends explicitly on the state of 90 deg domain walls: the more 90 deg domain wall area available, the lower the elastic modulus. New experimental results obtained for three types of carbon and pure iron samples are presented. The magnetoacoustic response due to magnetization perpendicular to the uniaxial stress axis is considered as well as the magnetoacoustic response due to magnetization parallel to the uniaxial stress axis.

  10. Comparison of estimated core body temperature measured with the BioHarness and rectal temperature under several heat stress conditions.

    Seo, Yongsuk; DiLeo, Travis; Powell, Jeffrey B; Kim, Jung-Hyun; Roberge, Raymond J; Coca, Aitor


    Monitoring and measuring core body temperature is important to prevent or minimize physiological strain and cognitive dysfunction for workers such as first responders (e.g., firefighters) and military personnel. The purpose of this study is to compare estimated core body temperature (Tco-est), determined by heart rate (HR) data from a wearable chest strap physiology monitor, to standard rectal thermometry (Tre) under different conditions.  Tco-est and Tre measurements were obtained in thermoneutral and heat stress conditions (high temperature and relative humidity) during four different experiments including treadmill exercise, cycling exercise, passive heat stress, and treadmill exercise while wearing personal protective equipment (PPE).  Overall, the mean Tco-est did not differ significantly from Tre across the four conditions. During exercise at low-moderate work rates under heat stress conditions, Tco-est was consistently higher than Tre at all-time points. Tco-est underestimated temperature compared to Tre at rest in heat stress conditions and at a low work rate under heat stress while wearing PPE. The mean differences between the two measurements ranged from -0.1 ± 0.4 to 0.3 ± 0.4°C and Tco-est correlated well with HR (r = 0.795 - 0.849) and mean body temperature (r = 0.637 - 0.861).  These results indicate that, the comparison of Tco-est to Tre may result in over- or underestimation which could possibly lead to heat-related illness during monitoring in certain conditions. Modifications to the current algorithm should be considered to address such issues.

  11. Slow Replication Fork Velocity of Homologous Recombination-Defective Cells Results from Endogenous Oxidative Stress.

    Wilhelm, Therese; Ragu, Sandrine; Magdalou, Indiana; Machon, Christelle; Dardillac, Elodie; Técher, Hervé; Guitton, Jérôme; Debatisse, Michelle; Lopez, Bernard S


    Replications forks are routinely hindered by different endogenous stresses. Because homologous recombination plays a pivotal role in the reactivation of arrested replication forks, defects in homologous recombination reveal the initial endogenous stress(es). Homologous recombination-defective cells consistently exhibit a spontaneously reduced replication speed, leading to mitotic extra centrosomes. Here, we identify oxidative stress as a major endogenous source of replication speed deceleration in homologous recombination-defective cells. The treatment of homologous recombination-defective cells with the antioxidant N-acetyl-cysteine or the maintenance of the cells at low O2 levels (3%) rescues both the replication fork speed, as monitored by single-molecule analysis (molecular combing), and the associated mitotic extra centrosome frequency. Reciprocally, the exposure of wild-type cells to H2O2 reduces the replication fork speed and generates mitotic extra centrosomes. Supplying deoxynucleotide precursors to H2O2-exposed cells rescued the replication speed. Remarkably, treatment with N-acetyl-cysteine strongly expanded the nucleotide pool, accounting for the replication speed rescue. Remarkably, homologous recombination-defective cells exhibit a high level of endogenous reactive oxygen species. Consistently, homologous recombination-defective cells accumulate spontaneous γH2AX or XRCC1 foci that are abolished by treatment with N-acetyl-cysteine or maintenance at 3% O2. Finally, oxidative stress stimulated homologous recombination, which is suppressed by supplying deoxynucleotide precursors. Therefore, the cellular redox status strongly impacts genome duplication and transmission. Oxidative stress should generate replication stress through different mechanisms, including DNA damage and nucleotide pool imbalance. These data highlight the intricacy of endogenous replication and oxidative stresses, which are both evoked during tumorigenesis and senescence initiation

  12. Orientation on quantitative IR-thermografy in wall-shear stress measurements

    Mayer, R.


    Wall-shear stresses are highly important in the aerodynamic design of aircraft, because they determine the drag and thus the fuel consumption of an airplane. Due to this importance many different measurement techniques have been developed. Most of these techniques are intrusive, which means that the

  13. Association between objectively measured physical activity, chronic stress and leukocyte telomere length.

    von Känel, Roland; Bruwer, Erna J; Hamer, Mark; de Ridder, J Hans; Malan, Leoné


    Physical activity (PA) attenuates chronic stress and age-related and cardiovascular disease risks, whereby potentially slowing telomere shortening. We aimed to study the association between seven-day objectively measured habitual PA, chronic stress and leukocyte telomere length. Study participants were African (N.=96) and Caucasian (N.=107) school teachers of the Sympathetic activity and Ambulatory Blood Pressure in Africans study. All lifestyle characteristics (including PA) were objectively measured. The general health questionnaire and serum cortisol were assessed as psychological and physical measures of chronic stress. Leukocyte telomere length was measured using the quantitative real-time polymerase chain reaction. Africans had significantly shorter telomeres (Pstress or telomere length. However, more time spent with light intensity PA time was significantly and independently correlated with lower waist circumference (r=-0.21, P=0.004); in turn, greater waist circumference was significantly associated shorter telomeres (β=-0.17 [-0.30, -0.03], P=0.017). Habitual PA of different intensity was not directly associated with markers of chronic stress and leukocyte telomere length in this biethnic cohort. However, our findings suggest that light intensity PA could contribute to lowered age-related disease risk and healthy ageing by facilitating maintenance of a normal waist circumference.

  14. Enhancing Maritime Education and Training: Measuring a Ship Navigator's Stress Based on Salivary Amylase Activity

    Murai, Koji; Wakida, Shin-Ichi; Miyado, Takashi; Fukushi, Keiichi; Hayashi, Yuji; Stone, Laurie C.


    Purpose: The purpose of this paper is to propose that the measurement of salivary amylase activity is an effective index to evaluate the stress of a ship navigator for safe navigation training and education. Design/methodology/approach: Evaluation comes from the simulator and actual on-board experiments. The subjects are real captains who have…

  15. Obtaining Heat Stress Measurements. Module 15. Vocational Education Training in Environmental Health Sciences.

    Consumer Dynamics Inc., Rockville, MD.

    This module, one of 25 on vocational education training for careers in environmental health occupations, contains self-instructional materials on obtaining heat stress measurements. Following guidelines for students and instructors and an introduction that explains what the student will learn are three lessons: (1) naming and describing the…

  16. Biotechnology Predictors of Physical Security Personnel Performance: Cerebral Potential Measures Related to Stress.


    Rosenman, 1983), are oriented primarily toward matching personalities with certain patterns of clinical responses to stress. Other, more general schemes...measured for the medio -basal region of the frontal lobes or for the limbic formations. Factual information relevant to problems of this kind will

  17. Job stress and coping strategies among nurses: results of a self report survey.

    McAbee, R


    1. Many employers do not have the resources for sophisticated investigation, development, and implementation of stress reduction programs for employee health. This does not eliminate the need for such programs. 2. Occupational health nurses can develop stress reduction programs building on individual coping strategies used by workers. A simple survey of workers could provide baseline information for the development of these programs. 3. Exercise, open atmosphere for discussion, relaxation, and taking a break were the top four coping strategies reported by nurses and non-nurse female employees. Employers could easily support stress reduction programs built on these strategies.

  18. Influence of beverage composition on the results of erosive potential measurement by different measurement techniques.

    Jager, D.H.; Vieira, A.M.; Ruben, J.L.; Huysmans, M.C.D.N.J.M.


    The influence of beverage composition on the measurement of erosive potential is unclear. The aim of this study was to evaluate whether beverage composition influences the measurement of erosive potential and to evaluate the influence of exposure in small and large volumes. Eleven beverages were inc

  19. Influence of beverage composition on the results of erosive potential measurement by different measurement techniques

    Jager, D. H. J.; Vieira, A. M.; Ruben, J. L.; Huysmans, M. C. D. N. J. M.


    The influence of beverage composition on the measurement of erosive potential is unclear. The aim of this study was to evaluate whether beverage composition influences the measurement of erosive potential and to evaluate the influence of exposure in small and large volumes. Eleven beverages were inc

  20. Prenatal Stress as a Modifier of Associations between Phthalate Exposure and Reproductive Development: results from a Multicentre Pregnancy Cohort Study.

    Barrett, Emily S; Parlett, Lauren E; Sathyanarayana, Sheela; Redmon, J Bruce; Nguyen, Ruby H N; Swan, Shanna H


    Prenatal phthalate exposure is associated with altered male reproductive tract development, and in particular, shorter anogenital distance (AGD). AGD, a sexually dimorphic index of prenatal androgen exposure, may also be altered by prenatal stress. How these exposures interact to impact AGD is unknown. Here, we examine the extent to which associations between prenatal phthalate exposure and infant AGD are modified by prenatal exposure to stressful life events (SLEs). Phthalate metabolites [including those of diethylhexyl phthalate (DEHP) and their molar sum (ΣDEHP)] were measured in first trimester urine from 738 pregnant women participating in The Infant Development and the Environment Study (TIDES). Women completed questionnaires on SLEs, and permitted infant AGD measurements at birth. Subjects were classified as 'lower' and 'higher' stress (0 first trimester SLEs vs. 1+).We estimated relationships between phthalate concentrations and AGD (by infant sex and stress group) using adjusted multiple regression interaction models. In the lower stress group, first trimester ΣDEHP was inversely associated with two measures of male AGD: anoscrotal distance (AGD-AS; β = -1.78; 95% CI -2.97, -0.59) and anopenile distance (AGD-AP; β = -1.61; 95% CI -3.01, -0.22). By contrast, associations in the higher stress group were mostly positive and non-significant in male infants. No associations were observed in girls. Associations between prenatal phthalate exposure and altered genital development were only apparent in sons of mothers who reported no SLEs during pregnancy. Prenatal stress and phthalates may interact to shape fetal development in ways that have not been previously explored. © 2015 John Wiley & Sons Ltd.

  1. Psychological Stress Measure (PSM-9): integration of an evidence-based approach to assessment, monitoring, and evaluation of stress in physical therapy practice.

    Lemyre, Louise; Lalande-Markon, Marie-Pierre


    Stress can be a primary or secondary contributor to ill health via excessive and sustained sympathetic arousal leading to ischemic heart disease, hypertension, stroke, obesity, and mental ill health, or through related behaviors such as smoking, substance abuse, and over or inappropriate eating; or as a contextual variable in terms of risk factor and lifestyle outcome. In addition, psychosocial stress can impair recovery from any pathological insult or injury. Most assessments of stress relate to life events, and both past and current life stressors, acute and chronic, play a major role. However, beyond the impact of stressors, it is the reported state of feeling stressed that is the critical predictor of ill health. This article describes stress and its correlates, discusses models of stress, and presents the nine-item Psychological Stress Measure (PSM-9). This tool is aimed directly at the state of feeling stressed, is suited for assessing stress clinically in the general population and serving as an outcome measure. The tool is valid and reliable and easy to administer in health care settings; it has a normal distribution, which makes it a very sensitive-to-change instrument in repeated measures to document progress.

  2. Blood Contamination in Saliva: Impact on the Measurement of Salivary Oxidative Stress Markers

    Natália Kamodyová


    Full Text Available Salivary oxidative stress markers represent a promising tool for monitoring of oral diseases. Saliva can often be contaminated by blood, especially in patients with periodontitis. The aim of our study was to examine the impact of blood contamination on the measurement of salivary oxidative stress markers. Saliva samples were collected from 10 healthy volunteers and were artificially contaminated with blood (final concentration 0.001–10%. Next, saliva was collected from 12 gingivitis and 10 control patients before and after dental hygiene treatment. Markers of oxidative stress were measured in all collected saliva samples. Advanced oxidation protein products (AOPP, advanced glycation end products (AGEs, and antioxidant status were changed in 1% blood-contaminated saliva. Salivary AOPP were increased in control and patients after dental treatment (by 45.7% and 34.1%, p<0.01. Salivary AGEs were decreased in patients after microinjury (by 69.3%, p<0.001. Salivary antioxidant status markers were decreased in both control and patients after dental treatment (p<0.05 and p<0.01. One % blood contamination biased concentrations of salivary oxidative stress markers. Saliva samples with 1% blood contamination are visibly discolored and can be excluded from analyses without any specific biochemic detection of blood constituents. Salivary markers of oxidative stress were significantly altered in blood-contaminated saliva in control and patients with gingivitis after dental hygiene treatment.

  3. The revised Stress Measurement of Female Marriage Immigrants in Korea: Evaluation of the psychometric properties.

    Park, Min Hee; Yang, Sook Ja; Chee, Yeon Kyung


    The twenty-one item Stress Measurement of Female Marriage Immigrants (SMFMI) was developed to assess stress of female marriage immigrants in Korea. This study reports the psychometric properties of a revised SMFMI (SMFMI-R) for application with female marriage immigrants to Korea who were raising children. Participants were 190 female marriage immigrants from China, Vietnam, the Philippines, and other Asian countries, who were recruited using convenience sampling between November 2013 and December 2013. Survey questionnaires were translated into study participants' native languages (Chinese, Vietnamese, and English). Principal component analysis yielded nineteen items in four factors (family, parenting, cultural, and economic stress), explaining 63.5% of the variance, which was slightly better than the original scale. Confirmatory factor analysis indicated adequate fit for the four-factor model. Based on classic test theory and item response theory, strong support was provided for item discrimination, item difficulty, and internal consistency (Cronbach's alpha = 0.923). SMFMI-R scores were negatively associated with Korean proficiency and subjective economic status. The SMFMI-R is a valid, reliable, and comprehensive measure of stress for female marriage immigrants and can provide useful information to develop intervention programs for those who may be at risk for emotional stress.

  4. Towards an automatic early stress recognition system for office environments based on multimodal measurements: A review.

    Alberdi, Ane; Aztiria, Asier; Basarab, Adrian


    Stress is a major problem of our society, as it is the cause of many health problems and huge economic losses in companies. Continuous high mental workloads and non-stop technological development, which leads to constant change and need for adaptation, makes the problem increasingly serious for office workers. To prevent stress from becoming chronic and provoking irreversible damages, it is necessary to detect it in its early stages. Unfortunately, an automatic, continuous and unobtrusive early stress detection method does not exist yet. The multimodal nature of stress and the research conducted in this area suggest that the developed method will depend on several modalities. Thus, this work reviews and brings together the recent works carried out in the automatic stress detection looking over the measurements executed along the three main modalities, namely, psychological, physiological and behavioural modalities, along with contextual measurements, in order to give hints about the most appropriate techniques to be used and thereby, to facilitate the development of such a holistic system.

  5. Measurement of urethral closure function in women with stress urinary incontinence

    Klarskov, N; Scholfield, D; Soma, K;


    , double-blind, placebo controlled, crossover study 17 women with stress urinary incontinence or mixed urinary incontinence received 4 mg esreboxetine or placebo for 7 to 9 days followed by a washout period before crossing over treatments. Urethral pressure reflectometry and urethral pressure profilometry...... esreboxetine patients had significantly fewer incontinence episodes and reported a treatment benefit (global impression of change) compared to placebo. CONCLUSIONS: The opening pressure measured with urethral pressure reflectometry was less variable compared to the parameters measured with urethral pressure...

  6. New measurement technology for diagnostic evaluation of stress and deformation states in building objects

    Kollataj, Robert; Kollataj, Jerzy


    This paper presents a new wireless measurement method for static and dynamic examination of buildings, bridges, masts, towers, steel structures, silos etc. by using new generation telemetric modules operating in intelligent radio network. The system provides a possibility of steel and reinforced concrete structures evaluation by measurement of mechanical stresses, deformation and temperature - depending on used sensor. Developed and built prototype system can be used for the on line monitoring, quality assessment and the usefulness of the building objects over long time periods.

  7. Internal tibial torsion correction study. [measurements of strain for corrective rotation of stressed tibia

    Cantu, J. M.; Madigan, C. M.


    A quantitative study of internal torsion in the entire tibial bone was performed by using strain gauges to measure the amount of deformation occuring at different locations. Comparison of strain measurements with physical dimensions of the bone produced the modulus of rigidity and its behavior under increased torque. Computerized analysis of the stress distribution shows that more strain occurs near the torqued ends of the bones where also most of the twisting and fracturing takes place.

  8. A comparison of X-ray stress measurement methods \\\\based on the fundamental equation

    Miyazaki, Toshiyuki; Sasaki, Toshihiko


    Stress measurement methods using X-ray diffraction (XRD methods) are based on so-called fundamental equations. The fundamental equation is described in the coordinate system that best suites the measurement situation, and, thus, making a comparison between different XRD methods is not straightforward. However, by using the diffraction vector representation, the fundamental equations of different methods become identical. Furthermore, the differences between the various XRD methods are in the ...

  9. Optical measurements on overhead optical fiber cables for stresses and damage identification

    Ravet, Fabien L.; Heens, Bernard; Daniaux, D.; Froidure, Jean-Christophe; Blondel, Michel; Dascotte, M.; Lots, P.


    This paper concerns the characterization of various trunks of an OPGW based network. No strong fiber aging has been observed but combined OTDR and PMD measurements have pointed out strong cable clamping at suspension pylon. Large local losses have been measured at both 1.55 micrometers and 1.6 micrometers and stress induced birefringent behavior have been experienced. PMD temporal evolution has also been studied. A correlation between temperature variation and PMD evolution has been observed.

  10. New methods to directly measure adhesive stress and movement on glass

    Watts, David C.; Marouf, A. S.; Heindl, Detlef


    Practical scientific methods have been devised to measure cure-shrinkage phenomena for a small-volume disk geometry of adhesive agents, in liquid or paste form. These can be conducted simply, reproducibly and quickly, typically 5-120 min, once the apparati are set up. Originally utilised to measure shrinkage behavior in photocuring dental adhesives and biomaterials, the measurements may be applied as well to adhesives for fiber optic and optical applications. They are especially suitable for UV and visible-light curing adhesives. The 'bonded-disk' method is used for the measurement of shrinkage-strain kinetics and the Bioman method for shrinkage-stress of adhesives.

  11. The Relation of Arm Exercise Peak Heart Rate to Stress Test Results and Outcome

    Xian, Hong; Liu, Weijian; Marshall, Cynthia; Chandiramani, Pooja; Bainter, Emily; Martin, III, Wade H


    PURPOSEArm exercise is an alternative to pharmacologic stress testing for >50% of patients unable to perform treadmill exercise but no data exist regarding the effect of attained peak arm exercise heart rate on test sensitivity...

  12. Mechanical Stress Results in Immediate Accumulation of Glucosinolates in Fresh-Cut Cabbage

    Požrl, Tomaž; Cigić, Blaž; Demšar, Lea; Hribar, Janez; Polak, Tomaž


    The intensity of mechanical stress and the temperature significantly affect the levels of individual and total glucosinolates in shredded white cabbage (cv. Galaxy). Mild processing (shredding to 2 mm thickness) at 8...

  13. Nondestructive measurement of the residual stress TiN thin film coated on AISI 304 substrate by x-ray stress analyzer

    Zhang, Y. K.; Feng, A. X.; Lu, J. Z.; Kong, D. J.; Tang, C. P.


    Titanium nitride films are deposited on AISI 304 steel with a hollow-cathode-discharge (HCD) ion-plating technique. The status of residual stresses in TiN thin film coated on AISI304 substrate by HCD is studied by x-ray diffraction stress analyzer. By analyzing morphology of the residual stress of TiN thin film at interface between TiN film and AISI 304 substrate, the adhering mechanism of TiN thin film is understood as follows: the mechanical interlocking had important contribution to the adhesion strength, the thermal stress is the major factor which resulting TiN thin film peeling off spontaneously. The results show that the value of thin film is -210MPa~-650Mpa, and the thermal stress is compressive, the intrinsic stress is tensile, origins of the residual stress are primarily discussed.

  14. [Post-traumatic stress disorder in Germany. Results of a nationwide epidemiological study].

    Maercker, A; Forstmeier, S; Wagner, B; Glaesmer, H; Brähler, E


    In a representative epidemiological study (n=2426) with a broad age range of respondents (14-93 years), prevalence rates of traumatic life events, post-traumatic stress disorder (PTSD), and partial PTSD were estimated. A standardized interview using the trauma checklist of the Composite International Diagnostic Interview and a DSM-IV PTSD symptom checklist (Modified PTSD Symptom Scale) were applied. One-month prevalence rates were 2.3% for DSM-IV PTSD and 2.7% for partial PTSD. There were no gender differences but age-group differences did appear: among persons older than 60, the prevalence of PTSD was 3.4%, whereas the prevalence was estimated at 1.3% among persons aged 14-29 years and 1.9% among those aged 30-59 years. Partial PTSD exhibited the same age distribution, with 3.8% in the elderly, 2.4% in the middle-aged, and 1.3% in young adults. The results correspond with those of other international studies taking war-related consequences for older age groups into account. Our representative study provides the first evidence of higher PTSD prevalence rates among older age groups in the German population, which is assumed to be related to consequences of World War II.

  15. Mechanical Stress Evaluation of Si Metal-Oxide-Semiconductor Field-Effect Transistor Structure Using Polarized Ultraviolet Raman Spectroscopy Measurements and Calibrated Technology-Computer-Aided-Design Simulations

    Satoh, Akira; Tada, Tetsuya; Poborchii, Vladimir; Kanayama, Toshihiko; Satoh, Shigeo; Arimoto, Hiroshi


    The mechanical stresses in Si metal-oxide-semiconductor field-effect transistors (MOSFETs) were evaluated by polarized UV Raman spectroscopy measurements and stress simulations. To calibrate stress parameters of the materials used in the Si MOSFETs, we compared measured and simulated Raman frequency shifts on the cleaved Si(110) surfaces of the MOSFETs. Consequently, we extracted intrinsic stress values of -400 MPa for a SiO2, -200 MPa for polycrystalline Si (poly-Si), 700 MPa for Ni silicide, 1250 MPa for a SiN tensile stress liner, and -3500 MPa for a SiN compressive stress liner by finding good agreement between the measured and simulated Raman shift distributions. To verify our stress simulation, we investigated the source/drain width dependences of Raman frequency shifts near the channel regions of Si MOSFETs by top-view Raman measurements. The calculated Raman frequency shifts agreed well with the results of polarized Raman measurements in terms of not only relative tendencies but also absolute Raman shift values.


    P. S. Serenkov


    Full Text Available Necessity of system approach development to measurement modeling for the purpose of maintenance of the trust set level to their results is proved. The decision of a measuring problem subject to determined aim is considered as creation of models sequence: measurement process model and complex measuring channel model. As a demonstrative basis of maintenance of trust to result of measurements the complex of criteria of completeness and irredundant is formulated.

  17. Measuring stress level of dairy cows during milking using by geometric indices of heart rate variability

    Levente Kovács


    Full Text Available AbstractHeart rate (HR and heart rate variability (HRV were investigated in cows (n=32, age: 3.86 years, milk production: 35±2.5 kg, DIM: 150±15 milked in a parallel milking parlour. Geometric parameters of HRV (SD1 and SD2 were calculated using Poincare graphs. HRV indices of resting 1 h after midday milking (reference period were compared to those measured during the different phases of the evening milking (driving; in the holding pen; udder preparation; milking; after milking in the milking stall. There was no difference between the reference period and the different phases of milking in animal welfare terms. During the reference period SD2 (198.5 ms was significantly higher (p<0.05 than every other measured period suggesting an increasing parasympathetic tone after milking. This parasympathetic predominance decreased with time of the day (1.5 h after milking. SD2 was significantly affected by parity, by the breeding bull (p<0.01 and by milk production (p<0.05. SD2 was notably higher (102.8 ms in multiparous cows than in primiparous cows (p<0.017; α=0.005 during resting and milking. Results suggested that a conventional milking process is not really stressful for cows. Primiparous cows were more susceptible of milking process than multiparous ones. SD2 is a good marker of vagus activity and affected by several independent factors.

  18. Long-term changes in cognitive bias and coping response as a result of chronic unpredictable stress during adolescence

    Lauren eChaby


    Full Text Available Animals that experience adverse events in early life often have life-long changes to their physiology and behavior. Long-term effects of stress during early life have been studied extensively, but less attention has been given to the consequences of negative experiences solely during the adolescent phase. Adolescence is a particularly sensitive period of life when regulation of the glucocorticoid stress hormone response matures and specific regions in the brain undergo considerable change. Aversive experiences during this time might, therefore, be expected to generate long-term consequences for the adult phenotype. Here we investigated the long-term effects of exposure to chronic unpredictable stress during adolescence on adult decision making, coping response, cognitive bias, and exploratory behavior in rats. Rats exposed to chronic unpredictable stress (e.g. isolation, crowding, cage tilt were compared to control animals that were maintained in standard, predictable conditions throughout development. Unpredictable stress during adolescence resulted in a suite of long-term behavioral and cognitive changes including a negative cognitive bias (F1,12 = 5.000, P < 0.05, altered coping response (T1,14 = 2.216, P = 0.04, and accelerated decision making (T1,14 = 3.245, P = 0.01. Exposure to chronic stress during adolescence also caused a short-term increase in boldness behaviors; in a novel object test 15 days after the last stressor, animals exposed to chronic unpredictable stress had decreased latencies to leave a familiar shelter and approach a novel object (T1,14 = 2.240, P = 0.04; T1,14 = 2.419, P = 0.03, respectively. The results showed that stress during adolescence has long-term impacts on behavior and cognition that affect the interpretation of ambiguous stimuli, behavioral response to adverse events, and how animals make decisions. Stress during adolescence also induced short-term changes in the way animals moved around a novel environment.


    Knowles, C. R.


    Full Text Available Selective laser melting (SLM of Ti-6Al-4V has significant potential in the aerospace and biotechnology industries. SLM employs a focused laser beam to melt successive layers of metallic powder into complex components. This process can result in the generation of high thermally-induced residual stresses. These residual stresses, together with micro-flaws/ pores from the inherent fabrication process, may lead to premature fatigue crack initiation and propagation at relatively low cyclic stresses. The hole-drilling strain gauge method was used to evaluate residual stresses within SLM Ti-6Al-4V specimens, with the intention of understanding the associated mechanisms for the successful application of SLM Ti-6Al-4V in industry.

  20. Instrumented thick-walled tube method for measuring thermal pressure in fluids and isotropic stresses in thermosetting resins

    Merzlyakov, Mikhail; Simon, Sindee L.; McKenna, Gregory B.


    We have developed a method for measuring the thermal pressure coefficient and cure-induced and thermally induced stresses based on an instrumented thick-walled tube vessel. The device has been demonstrated at pressures up to 330 MPa and temperatures to 300 °C. The method uses a sealed stainless steel thick-walled tube to impose three-dimensional isotropic constraints. The tube is instrumented with strain gauges in hoop and in axial directions and can be used in open or closed configurations. By making measurements of the isotropic stresses as a function of temperature, the method allows determination of the thermal pressure coefficient in both the glassy and rubbery (or liquid) states. The method also can be used to measure isotropic stress development in thermosetting resins during cure and subsequent thermal cycling. Experimental results are presented for sucrose benzoate, di-2-ethylhexylsebacate, and an epoxy resin. The current report shows that the method provides reliable estimates for the thermal pressure coefficient. The thermal pressure coefficient is determined with resolution on the order of 10kPa/K. Among advantages of the method is that the tubes are reusable, even when measurements are made for cure response of thermosetting resins.

  1. Stresses and Strains in a Plate Resulting from two Closely-Spaced Interference-Fit Fasteners


    Trans-Australia Airlines, Library Qantas Airways Limited Ansett Airlines of Australia, Library Commonwealth Aircraft Corporation, Library Hawker fasteners (nominal centre distance equalling two hole diameters) in a D6ac steel plate. For comparison, a finite element analysis was performed...for the same geometry using the penalty element method. Measured strains showed broad agreementwith the results of the finite element analysis and the

  2. Further Tests of Changes in Fish Escape Behavior Resulting from Sublethal Stresses Associated with Hydroelectric Turbine Passage

    Ryon, M.G.


    and another 70 under control conditions (either transferred from the holding tank or injected into the Alden loop downstream of turbine). The resulting image files were analyzed for a variety of behavioral measures including: presence of a startle response, time to first reaction, duration of reaction, time to formation of the maximum C-shape, time to completion of the C-shape, completeness of the C-shape, direction of turn, and degree of turn. The data were evaluated for statistical significance and patterns of response were identified. The most immediate measure of potential changes in fish behavior was whether test and control fish exhibited a startle response. Unlike earlier studies, there was no significant difference among the treatment group and the controls for startle response. The majority of rainbow trout in all groups responded to the startle stimulus. There were however, significant differences in some of the particular aspects of the subsequent escape behavior. The time to first reaction, the duration of the reaction, and the times associated with maximum C-shape formation were all significantly different between the tank controls and the two groups of fish injected into the Alden turbine loop. There were no significant differences in behavioral responses between the trout passed through the turbine runner and those injected downstream of the runner. Other behavioral parameters, such as C-shape completeness ratio, were not significantly affected. The effect of the Alden turbine loop on some aspects of the escape behavior suggest that the process of movement through the system is important, but that the role of the added stress, if any, of passage through the turbine runner is minimal. It may be important that statistically significant differences in timing of phases of the startle response were detected, even though the majority of stressed fish still exhibited the startle response. This is in contrast to earlier studies, where timing of phases of the

  3. Comparison between Neutron Diffraction measurements and numerical simulation of residual stresses of a Wire-Drawing process

    Tomaz Fantin de Souza


    Full Text Available In this work, a drawing processed was simulated to calculate forces and the resulting residual stresses in the material. The calculated residual stresses were compared with experimentally measured residual stresses by the Neutron Diffraction Method. The modeled process was the Wire Drawing. The necessary parameters to model the process were taken from an industrial currently used process. Rods of an AISI 1045 steel with nominal diameters of 21.46 mm were reduced to 20.25 mm by drawing with an drawing angle of 15°. Compression tests were used to determinate flow curves of the real material an used in the simulation models. The possibility to estimate drawing forces by numerical simulation was evaluated by comparing simulated results with values from empirical equations given by the literature. The results have shown a sufficient accuracy for the calculation of forces, but the comparison of residual stresses has shown differences to the experimentally determined ones that can be minimized by the consideration of high strain rates in the compression tests, anisotropy of the material and kinematic hardening.

  4. A Novel Deflection Method for Measuring the Growth Stress of Thermally Growing Oxide Scales


    A kind of new deflection technique has been developed for measuring the growth stress of thermally growing oxide scales duringhigh temperature oxidation of alloys. The average growth stresses in oxide scales such as Al2O3, NiO and Cr2O3 formed onthe surface of the superalloys can be investigated by this technique. Unlike the comventional deflection method, the novelmethod does not need to apply a coating for preventing one main face of thin strip specimen from oxidizing and can be usedunaer tne condition of longer time and higher temperature.

  5. First Measurement of the Magnetic Turbulence Induced Reynolds Stress in a Tokamak

    徐国盛; 万宝年; 宋梅


    Reynolds stress component due to magnetic turbulence was first measured in the plasma edge region of the HT- 7 superconducting tokamak using an insertable magnetic probe. A radial gradient of magnetic Reynolds stress was observed to be dose to the velocity shear layer location; however, in this experiment its contribution to driving the poloidal flows is small compared to the electrostatic component. The electron heat transport driven by magnetic turbulence is quite small and cannot account for the total energy transport at the plasma edge.

  6. Through-Thickness Measurements of Residual Stresses in an Overlay Dissimilar Weld Pipe using Neutron Diffraction

    Woo, Wan Chuck; EM, Vyacheslav; Lee, Ho Jin; Kim, Kang Soo; Kang, Mi Hyun; Joo, Jong Dae; Seong, Baek Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Byeon, Jin Gwi; Park, Kwang Soo [Doosan Heavy Industries and Construction Co., Changwon (Korea, Republic of)


    The distribution of residual stresses in dissimilar material joints has been extensively studied because of the wide applications of the dissimilar welds in many inevitable complex design structures. Especially the cracking of dissimilar welding has been a long standing issue of importance in many components of the power generation industries such as nuclear power plant, boiling pressure system, and steam generators. In particular, several failure analysis and direct observations have shown that critical fractures have frequently occurred in one side of the dissimilar welded parts. For example, the heat-affected zone on the ferrite steel side is known to critical in many dissimilar welding pipes when ferrite (low carbon steel) and austenite (stainless) steels are joined. The main cause of the residual stresses can be attributed to the mismatch in the coefficient of thermal expansion between the dissimilar metals (ferrite and austenite). Additional cladding over circumferential welds is known to reinforce the mechanical property due to the beneficial compressive residual stress imposed on the weld and heat-affected zone. However, science-based quantitative measurement of the through thickness residual stress distribution is very limited in literature. The deep penetration capability of neutrons into most metallic materials makes neutron diffraction a powerful tool to investigate and map the residual stresses of materials throughout the thickness and across the weld. Furthermore, the unique volume averaged bulk characteristic of materials and mapping capability in three dimensions are suitable for the engineering purpose. Thus, the neutron-diffraction measurement method has been selected as the most useful method for the study of the residual stresses in various dissimilar metal welded structures. The purpose of this study is to measure the distribution of the residual stresses in a complex dissimilar joining with overlay in the weld pipe. Specifically, we measured

  7. Measurement of wall shear stress in chick embryonic heart using optical coherence tomography

    Ma, Zhenhe; Dou, Shidan; Zhao, Yuqian; Wang, Yi; Suo, Yanyan; Wang, Fengwen


    The cardiac development is a complicated process affected by genetic and environmental factors. Wall shear stress (WSS) is one of the components which have been proved to influence the morphogenesis during early stages of cardiac development. To study the mechanism, WSS measurement is a step with significant importance. WSS is caused by blood flow imposed on the inner surface of the heart wall and it can be determined by calculating velocity gradients of blood flow in a direction perpendicular to the wall. However, the WSS of the early stage embryonic heart is difficult to measure since the embryonic heart is tiny and beating fast. Optical coherence tomography (OCT) is a non-invasive imaging modality with high spatial and temporal resolution, which is uniquely suitable for the study of early stage embryonic heart development. In this paper, we introduce a method to measure the WSS of early stage chick embryonic heart based on high speed spectral domain optical coherence tomography (SDOCT). 4D (x,y,z,t) scan was performed on the outflow tract (OFT) of HH18 (~3 days of incubation) chick embryonic heart. After phase synchronization, OFT boundary segmentation, and OFT center line calculation, Doppler angle of the blood flow in the OFT can be achieved (This method has been described in previous publications). Combining with the Doppler OCT results, we calculate absolute blood flow velocity distribution in the OFT. The boundary of the OFT was segmented at each cross-sectional structural image, then geometrical center of the OFT can be calculated. Thus, the gradients of blood flow in radial direction can be calculated. This velocity gradient near the wall is termed wall shear rate and the WSS value is proportional to the wall shear rate. Based on this method, the WSS at different heart beating phase are compare. The result demonstrates that OCT is capable of early stage chicken embryonic heart WSS study.

  8. Elaboration of the Environmental Stress Hypothesis–Results from a Population-Based 6-Year Follow-Up

    Wagner, Matthias; Jekauc, Darko; Worth, Annette; Woll, Alexander


    The aim of this paper was to contribute to the elaboration of the Environmental Stress Hypothesis framework by testing eight hypotheses addressing the direct impact of gross motor coordination problems in elementary-school on selected physical, behavioral and psychosocial outcomes in adolescence. Results are based on a longitudinal sample of 940 participants who were (i) recruited as part of a population-based representative survey on health, physical fitness and physical activity in childhood and adolescence, (ii) assessed twice within 6 years, between the ages of 6 and 10 years old as well as between the ages of 12 and 16 years old (Response Rate: 55.9%) and (iii) classified as having gross motor coordination problems (N = 115) or having no gross motor coordination problems (N = 825) at baseline. Motor tests from the Körperkoordinationstest, measures of weight and height, a validated physical activity questionnaire as well as the Strength and Difficulties Questionnaire were conducted. Data were analyzed by use of binary logistic regressions. Results indicated that elementary-school children with gross motor coordination problems show a higher risk of persistent gross motor coordination problems (OR = 7.99, p elementary-school children without gross motor coordination problems. However, elementary-school children with gross motor coordination problems did not show a significantly higher risk of peer problems (OR = 1.35, p = 0.164) or diminished prosocial behavior (OR = 1.90, p = 0.168) in adolescence, respectively in comparison to elementary-school children without gross motor coordination problems. This study is the first to provide population-based longitudinal data ranging from childhood to adolescence in the context of the Environmental Stress Hypothesis which can be considered a substantial methodological progress. In summary, gross motor coordination problems represent a serious issue for a healthy transition from childhood to adolescence which

  9. New Computer Automated Holo-Photoelastic Method For Measuring Planar Principal Stress Magnitudes And Orientation

    Brown, G. M.; Sullivan, J. L.


    A complete experimental determination of the stress and strain fields in an arbitrary deformed structure is generally unavailable. However, for two dimensional elasticity problems, such determinations are possible since in those cases one needs only to solve for three stresses (two normal and one shear). In fact, such determinations have been conducted quite often. By using isochromatic and isoclinic photoelastic data, the shear difference and numerical iteration techniques (1) and the least squares techniques (2) have been successfully used for complete stress field determinations of two dimensional elasticity problems. Though the shear difference technique can be particularly sensitive to cumulative errors resulting from numerical integration, the least squares technique is not affected by this and appears to yield better accuracy. The methods just cited use both experimental data and one or more mechanics conditions(e.g., the equations of equilibrium) to determine the stress field. However, the stress field can also be obtained from experimental data alone for planar elasticity problems, if there is enough of it to solve for the three stresses. For example, the Moire* technique or the combination of isochromatic, isoclinic, and isopachic data (for transparent models) can be used for such determinations. Further, with the marriage of advanced image processing equipment to computers, such analyses using this type of data can be conveniently conducted. It is even possible that such analyses could be more accurate than those using the combined experimental/numerical techniques cited above. The purposes of this report are two fold: i) to describe a single apparatus for obtaining isochromatic, isopachic, and isoclinic results for complete stress field determinations of two dimensional transparent models, and ii) to compare experimental and theoretical stress field values for an antisymmetrically loaded beam obtained using that apparatus.

  10. Thermal stress measurement in continuous welded rails using the hole-drilling method

    Zhu, Xuan; Lanza di Scalea, Francesco; Fateh, Mahmood


    The absence of expansion joints in Continuous Welded Rail (CWR) has created the need for the railroad industry to determine the in-situ level of thermal stresses so as to prevent train accidents caused by rail buckling in hot weather and by rail breakage in cold weather. The development of non-destructive or semi-destructive methods for determining the level of thermal stresses in rails is today a high research priority. This study explores the known hole-drilling method as a possible solution to this problem. A new set of calibration coefficients to compute the relieved stress field with the finer hole depth increments was determined by a 3D Finite Element Analysis that modeled the entire hole geometry, including the mechanics of the hole bottom and walls. To compensate the residual stress components, a linear relationship was experimentally established between the longitudinal and the vertical residual stresses of two common sizes of rails, the 136RE and the 141RE, with statistical significance. This result was then utilized to isolate the longitudinal thermal stress component in hole-drilling tests conducted on the 136RE and 141RE thermally-loaded rails at the Large-scale CWR Test-bed of UCSD's Powell Research Laboratories. The results from the Test-bed showed that the hole-drilling procedure, with the appropriate residual stress compensation, can indeed estimate the in-situ thermal stresses to achieve a +/-5°F accuracy of Neutral Temperature determination with a 90% statistical confidence, which is the desired industry gold standard.

  11. Mindfulness Training and Reductions in Teacher Stress and Burnout: Results from Two Randomized, Waitlist-Control Field Trials

    Roeser, Robert W.; Schonert-Reichl, Kimberly A.; Jha, Amishi; Cullen, Margaret; Wallace, Linda; Wilensky, Rona; Oberle, Eva; Thomson, Kimberly; Taylor, Cynthia; Harrison, Jessica


    The effects of randomization to mindfulness training (MT) or to a waitlist-control condition on psychological and physiological indicators of teachers' occupational stress and burnout were examined in 2 field trials. The sample included 113 elementary and secondary school teachers (89% female) from Canada and the United States. Measures were…

  12. Adolescent traumatic stress experience results in less robust conditioned fear and post-extinction fear cue responses in adult rats.

    Moore, Nicole L T; Gauchan, Sangeeta; Genovese, Raymond F


    Early exposure to a traumatic event may produce lasting effects throughout the lifespan. Traumatic stress during adolescence may deliver a distinct developmental insult compared with more-often studied neonatal or juvenile traumatic stress paradigms. The present study describes the lasting effects of adolescent traumatic stress upon adulthood fear conditioning. Adolescent rats were exposed to a traumatic stressor (underwater trauma, UWT), then underwent fear conditioning during adulthood. Fear extinction was tested over five conditioned suppression extinction sessions three weeks later. The efficacies of two potential extinction-enhancing compounds, endocannabinoid reuptake inhibitor AM404 (10mg/kg) and M1 muscarinic positive allosteric modulator BQCA (10mg/kg), were also assessed. Finally, post-extinction fear responses were examined using a fear cue (light) as a prepulse stimulus. Rats traumatically stressed during adolescence showed blunted conditioned suppression on day 1 of extinction training, and AM404 reversed this effect. Post-extinction startle testing showed that fear conditioning eliminates prepulse inhibition to the light cue. Startle potentiation was observed only in rats without adolescent UWT exposure. AM404 and BQCA both ameliorated this startle potentiation, while BQCA increased startle in the UWT group. These results suggest that exposure to a traumatic stressor during adolescence alters developmental outcomes related to stress response and fear extinction compared to rats without adolescent traumatic stress exposure, blunting the adulthood fear response and reducing residual post-extinction fear expression. Efficacy of pharmacological interventions may also vary as a factor of developmental traumatic stress exposure.

  13. Characterization of Residual Stresses in Ferrous Components by Magnetic Anisotropy Measurements Using a Hall Effect Sensor Array Probe

    Lo, C. C. H.


    A new surface sensor probe comprising an angular array of Hall effect sensors has been developed for characterization of residual stresses in ferrous materials by means of stress-induced magnetic anisotropy measurements. The sensor probe applies a radially spreading ac magnetic field to a test sample, and detects stray fields in different directions simultaneously to determine the principal stress axes. In situ measurements were conducted on a annealed steel plate under four-point bending stresses to evaluate the probe performance. The ratio of stray field signals measured along and perpendicular to the stress axis varies linearly with the surface stress, indicating the possibility of characterizing residual stresses in ferrous components using the sensor array probe.

  14. Grapheme-color synesthesia and posttraumatic stress disorder: preliminary results from the veterans health study.

    Hoffman, Stuart N; Zhang, Xiaopeng; Erlich, Porat M; Boscarino, Joseph A


    Posttraumatic stress disorder (PTSD) is associated with altered neuropsychological function, possibly including complex visual information processing. Grapheme-color synesthesia refers to the phenomenon that a particular letter or number elicits the visual perception of a specific color. The study objective was to assess if grapheme-color synesthesia was associated with PTSD among US veterans. We surveyed 700 veterans who were outpatients in a multihospital system in Pennsylvania. All veterans had served at least one warzone deployment. PTSD and grapheme-color synesthesia were assessed using validated research instruments. The mean age of veterans was 59 years, and 96% were men. The prevalence of current PTSD was 7% (95% confidence interval [CI] = 5.1-8.8), and current partial PTSD was 11% (95% CI = 9.3-14.0). The prevalence of current depression was 6% (95% CI = 4.7-8.3). Altogether, 6% (95% CI = 4.8-8.5) of veterans screened positive for grapheme-color synesthesia. Bivariate analyses suggested that grapheme-color synesthesia was associated with current PTSD (odds ratio [OR] = 3.4, p = .004) and current partial PTSD (OR = 2.4, p = .013), but not current depression (OR = 1.1, p = .91). Multivariate logistic regression results, adjusting for age, sex, marital status, level of education, current psychotropic medication use, and concussion history, confirmed these results. Grapheme-color synesthesia seems to be associated with PTSD among veterans who had been deployed. This finding may have implications for PTSD diagnostic screening and treatment. Research is recommended to confirm this finding and to determine if synesthesia is a risk indicator for PTSD among nonveterans.

  15. Response of the diatom Phaeodactylum tricornutum to photooxidative stress resulting from high light exposure.

    Nuno Domingues

    Full Text Available The response of microalgae to photooxidative stress resulting from high light exposure is a well-studied phenomenon. However, direct analyses of photosystem II (PSII D1 protein (the main target of photoinhibition in diatoms are scarce. In this study, the response of the diatom model species Phaeodactylum tricornutum to short-term exposure to high light was examined and the levels of D1 protein determined immunochemically. Low light (LL acclimated cells (40 µmol photons m(-2 s(-1 subjected to high light (HL, 1,250 µmol photons m(-2 s(-1 showed rapid induction of non-photochemical quenching (NPQ and ca. 20-fold increase in diatoxanthin (DT concentration. This resulted from the conversion of diadinoxanthin (DD to DT through the activation of the DD-cycle. D1 protein levels under LL decreased about 30% after 1 h of the addition of lincomycin (LINC, a chloroplast protein synthesis inhibitor, showing significant D1 degradation and repair under low irradiance. Exposure to HL lead to a 3.2-fold increase in D1 degradation rate, whereas average D1 repair rate was 1.3-x higher under HL than LL, leading to decreased levels of D1 protein under HL. There were significant effects of both HL and LINC on P. tricornutum maximum quantum yield of PSII (F(v/F(m, showing a reduction of active PSII reaction centres. Partial recovery of F(v/F(m in the dark demonstrates the photosynthetic resilience of this diatom to changes in the light regime. P. tricornutum showed high allocation of total protein to D1 and an active D1-repair cycle to limit photoinhibition.

  16. Stress-Release Seismic Source for Seismic Velocity Measurement in Mines

    Swanson, P. L.; Clark, C.; Richardson, J.; Martin, L.; Zahl, E.; Etter, A.


    Accurate seismic event locations are needed to delineate roles of mine geometry, stress and geologic structures in developing rockburst conditions. Accurate absolute locations are challenging in mine environments with rapid changes in seismic velocity due to sharp contrasts between individual layers and large time-dependent velocity gradients attending excavations. Periodic use of controlled seismic sources can help constrain the velocity in this continually evolving propagation medium comprising the miners' workplace. With a view to constructing realistic velocity models in environments in which use of explosives is problematic, a seismic source was developed subject to the following design constraints: (i) suitable for use in highly disturbed zones surrounding mine openings, (ii) able to produce usable signals over km-scale distances in the frequency range of typical coal mine seismic events (~10-100 Hz), (iii) repeatable, (iv) portable, (v) non-disruptive to mining operations, and (vi) safe for use in potentially explosive gaseous environments. Designs of the compressed load column seismic source (CLCSS), which generates a stress, or load, drop normal to the surface of mine openings, and the fiber-optic based source-initiation timer are presented. Tests were conducted in a coal mine at a depth of 500 m (1700 ft) and signals were recorded on the surface with a 72-ch (14 Hz) exploration seismograph for load drops of 150-470 kN (16-48 tons). Signal-to-noise ratios of unfiltered signals ranged from ~200 immediately above the source (500 m (1700 ft)) to ~8 at the farthest extent of the array (slant distance of ~800 m (2600 ft)), suggesting the potential for use over longer range. Results are compared with signals produced by weight drop and sledge hammer sources, indicating the superior waveform quality for first-arrival measurements with the CLCSS seismic source.

  17. Measuring stress responses in female Geoffroy's spider monkeys: Validation and the influence of reproductive state.

    Rodrigues, Michelle A; Wittwer, Dan; Kitchen, Dawn M


    Fecal glucocorticoid metabolites are increasingly used to investigate physiological stress. However, it is crucial for researchers to simultaneously investigate the effects of reproductive state because estradiol and placental hormones can affect circulating glucocorticoid concentrations. Reports on the relationships between glucocorticoids and reproductive state are inconsistent among females. Unlike several primate species that have heightened glucocorticoid activity during lactation, humans experience reduced glucocorticoid activity during lactation. Rather than a taxonomic difference, we hypothesize that this is a result of different environmental stressors, particularly the threat of infanticide. Here, we expand the number of wild primate species tested by validating a glucocorticoid assay for female Geoffroy's spider monkeys. We investigate the effects of reproductive state on their glucocorticoid concentrations. Utilizing a routine veterinary exam on a captive population, we determined that fecal glucocorticoid metabolites increase in response to a stressor (anesthesia), and this rise is detected approximately 24 hr later. Additionally, we found that extracted hormone patterns in a wild population reflected basic reproductive biology-estradiol concentrations were higher in cycling than lactating females, and in lactating females with older offspring who were presumably resuming their cycle. However, we found that estradiol and glucocorticoid concentrations were significantly correlated in lactating but not cycling females. Similarly, we found that reproductive state and estradiol concentration, but not stage of lactation, predicted glucocorticoid concentrations. Unlike patterns in several other primate species that face a relatively strong threat of infanticide, lactating spider monkeys experience reduced glucocorticoid activity, possibly due to attenuating effects of oxytocin and lower male-initiated aggression than directed at cycling females. More

  18. Stress

    Keller, Hanne Dauer


    Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb.......Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb....

  19. Stress

    Keller, Hanne Dauer


    Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb.......Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb....

  20. Internet-based stress management for distressed managers: results from a randomised controlled trial.

    Persson Asplund, Robert; Dagöö, Jesper; Fjellström, Ida; Niemi, Linnea; Hansson, Katja; Zeraati, Forough; Ziuzina, Masha; Geraedts, Anna; Ljótsson, Brjánn; Carlbring, Per; Andersson, Gerhard


    The aim of this randomised controlled trial (RCT) was to evaluate the efficacy of a guided internet-based stress management intervention (iSMI) among distressed managers compared with a attention control group (AC) with full access to treatment-as-usual. A total sample of 117 distressed managers, mainly employed in the healthcare, IT, communication and educational sector, were randomised to either iSMI (n=59) or an AC group (n=58). The iSMI consisted of eight modules including cognitive behavioural stress management and positive management techniques. Participants received a minimal and weekly guidance from a psychologist or master-level psychology student focusing on support, feedback and adherence to the intervention. Self-report data were assessed at pre, post and 6 months after the intervention. The primary outcome was perceived stress (Perceived Stress Scale-14). The secondary outcomes included mental and work-related health outcomes. Participants in the iSMI intervention reported significantly less symptoms of perceived stress (d=0.74, 95% CI 0.30 to 1.19) and burnout (d=0.95, 95% CI 0.53 to 1.37) compared with controls, at postassessment. Significant medium-to-large effect sizes were also found for depression, insomnia and job satisfaction. Long-term effects (6 months) were seen on the mental health outcomes. This is one of the first studies showing that iSMIs can be an effective, accessible and potentially time-effective approach of reducing stress and other mental-related and work-related health symptoms among distressed managers. Future studies are needed addressing distressed managers and the potential of indirect effects on employee stress and satisfaction at work. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  1. Acoustical and optical backscatter measurements of sediment transport in the 1988 1989 STRESS experiment

    Lynch, J. F.; Gross, T. F.; Sherwood, C. R.; Irish, J. D.; Brumley, B. H.


    During the 1988-1989 Sediment Transport Events on Shelves and Slopes (STRESS) experiment, a 1-MHz acoustic backscatter system (ABSS), deployed in 90 m of water off the California coast measured vertical profiles of suspended sediment concentration from 1.5 to (nominally) 26 meters above bottom (m.a.b.). An 8-week-long time series was obtained, showing major sediment transport events (storms) in late December and early January. Comparison of the acoustics measurements from 1.5 m.a.b. are made with optical backscatter system (OBS) concentration estimates lower in the boundary layer (0.25 m.a.b.). Correlations between ABSS and OBS concentration measurements and the boundary layer forcing functions (waves, currents, and their non-linear interaction) provided a variety of insights into the nature of the sediment transport of the STRESS site. Transport rates and integrated transport are seen to be dominated by the largest storm events.

  2. Enhancement to Non-Contacting Stress Measurement of Blade Vibration Frequency

    Platt, Michael; Jagodnik, John


    A system for turbo machinery blade vibration has been developed that combines time-of-arrival sensors for blade vibration amplitude measurement and radar sensors for vibration frequency and mode identification. The enabling technology for this continuous blade monitoring system is the radar sensor, which provides a continuous time series of blade displacement over a portion of a revolution. This allows the data reduction algorithms to directly calculate the blade vibration frequency and to correctly identify the active modes of vibration. The work in this project represents a significant enhancement in the mode identification and stress calculation accuracy in non-contacting stress measurement system (NSMS) technology when compared to time-of-arrival measurements alone.

  3. H/L ratio as a measurement of stress in laying hens - methodology and reliability.

    Lentfer, T L; Pendl, H; Gebhardt-Henrich, S G; Fröhlich, E K F; Von Borell, E


    Measuring the ratio of heterophils and lymphocytes (H/L) in response to different stressors is a standard tool for assessing long-term stress in laying hens but detailed information on the reliability of measurements, measurement techniques and methods, and absolute cell counts is often lacking. Laying hens offered different sites of the nest boxes at different ages were compared in a two-treatment crossover experiment to provide detailed information on the procedure for measuring and the difficulties in the interpretation of H/L ratios in commercial conditions. H/L ratios were pen-specific and depended on the age and aviary system. There was no effect for the position of the nest. Heterophiles and lymphocytes were not correlated within individuals. Absolute cell counts differed in the number of heterophiles and lymphocytes and H/L ratios, whereas absolute leucocyte counts between individuals were similar. The reliability of the method using relative cell counts was good, yielding a correlation coefficient between double counts of r > 0.9. It was concluded that population-based reference values may not be sensitive enough to detect individual stress reactions and that the H/L ratio as an indicator of stress under commercial conditions may not be useful because of confounding factors and that other, non-invasive, measurements should be adopted.

  4. Transducer for measuring normal and friction stress in contact zone during rolling

    Henningsen, Poul; Wanheim, Tarras; Arentoft, Mogens


    For the cold rolling process, knowledge about interface conditions is important since it directly influences the maximum reduction ratio and thereby the number of steps required for a given reduction. The mechanical properties of the produced sheet and the surface quality are also influenced...... by the friction conditions. To achieve this important information, measurements of the normal pressure and friction stresses in the deformation zone are requested. The interface conditions are analyzed by several authors [1-8] The direction of the friction stress is changing during the rolling gap....... At the entrance of the deformation zone, the peripherical velocity of the roll is higher than for the incoming material, which causes frictional stresses at the material acting in the rolling direction. At the outlet of the rolling gap, the velocity of the deformed material exceeds the velocity of the roll...

  5. [Changes in Kinetics of Chemiluminescence of Plasma as a Measure of Systemic Oxidative Stress in Humans].

    Sozarukova, M M; Polimova, A M; Proskurnina, E V; Vladimirov, Yu A


    Oxidative stress is a pathogenetic factor of many diseases. The control of its level is important for early diagnosis and therapy adjustment. In this work, antioxidant status was estimated in blood plasma. In the system of 2,2'-azo-bis(2-amidinopropane)dihydrochloride-luminol a set of chemiluminescence kinetic curve parameters is proposed for oxidative stress level estimation (the latent period τ(lat) and the increasing of analytical signal ΔI(CL)). Uric acid and albumin were shown as the main components that responsible for changes in chemiluminescence kinetic curve of plasma. Serum albumin undergoes oxidative modification in dose-depend manner under the action of UV irradiation, it causes the enhancement of antioxidant properties. Changes in plasma chemiluminescence kinetics are proposed as a measure of oxidative stress in human body.

  6. Stresses and residual stresses optical measurements systems evaluation; Avaliacao de sistemas opticos de medicao de tensoes e tensoes residuais em dutos

    Peixoto Filho, Flavio Tito; Goncalves Junior, Armando Albertazzi [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Lab. de Metrologia e Automatizacao (LABMETRO)


    There is always a constant concern about the pipelines' integrity. An important control parameter is the level of total mechanical stresses acting over the pipeline. However, the loading and residual stresses acting on a pipeline are not measured in the field as much as necessary. Technical difficulties and the high cost of the nowadays techniques and the hostile measurement conditions are the main reason for that. An alternative method has been developed at the Universidade Federal de Santa Catarina (UFSC) since 1992. A new optical measurement device is used to measure strains, mechanical stresses and residual stresses acting over the structure. A metrological and functional evaluation of this system is the main focus of this paper. (author)

  7. Results of the Round Robin on opening-load measurement conducted by ASTM Task Group E24.04.04 on Crack Closure Measurement and Analysis

    Phillips, Edward P.


    An experimental Round Robin on the measurement of the opening load in fatigue crack growth tests was conducted on Crack Closure Measurement and Analysis. The Round Robin evaluated the current level of consistency of opening load measurements among laboratories and to identify causes for observed inconsistency. Eleven laboratories participated in the testing of compact and middle-crack specimens. Opening-load measurements were made for crack growth at two stress-intensity factor levels, three crack lengths, and following an overload. All opening-load measurements were based on the analysis of specimen compliance data. When all of the results reported (from all participants, all measurement methods, and all data analysis methods) for a given test condition were pooled, the range of opening loads was very large--typically spanning the lower half of the fatigue loading cycle. Part of the large scatter in the reported opening-load results was ascribed to consistent differences in results produced by the various methods used to measure specimen compliance and to evaluate the opening load from the compliance data. Another significant portion of the scatter was ascribed to lab-to-lab differences in producing the compliance data when using nominally the same method of measurement.

  8. Perceived and measured physical activity and mental stress levels in obstetricians.

    Martinez de Tejada, Begoña; Jastrow, Nicole; Poncet, Antoine; Le Scouezec, Iona; Irion, Olivier; Kayser, Bengt


    Obstetric work generates important subjective and objective mental stress and is perceived as a physically demanding activity by obstetricians. The aim of this study was to quantify physical and mental stress levels in obstetricians at work and during leisure activities to investigate their association with overall physical activity levels and professional experience. 18 obstetricians at the maternity unit of the University of Geneva Hospitals were enrolled in a prospective observational study. Physical activity and stress levels were measured in two different activity sectors (delivery room and outpatient clinic) and outside work. Physical activity was assessed by questionnaire, visual analogue scale (VAS), and accelerometer. Mental stress levels were assessed by validated questionnaires, VAS, measurement of urine catecholamines and salivary cortisol, and night-time heart rate variability indices. Daily stress levels were higher at work compared to outside work (all, P = 0.002). Adrenalin (P = 0.002) and dopamine (P = 0.09) levels were elevated after a labour suite shift and a trend was observed for reduced heart rate variability during the night after this shift. The median average daily number of steps was 7132 (range, 5283-8649). Subjects reached a median of 32 min (range, 19-49 min) of moderate or higher intensity (≥ 1952 counts/min) daily physical activity. Contrary to perception, obstetrics work is not physically demanding. It is, however, accompanied by important subjective and objective mental stress that may have a negative impact on health when combined with a lack of regular daily physical activity. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  9. Psychological and Work Stress Assessment of Patients following Angioplasty or Heart Surgery: Results of 1-year Follow-up Study.

    Fiabane, Elena; Giorgi, Ines; Candura, Stefano M; Argentero, Piergiorgio


    The aim of this study was to explore changes in subjective psychological health and perceived work stress among patients who returned to work (RTW) after a multidisciplinary cardiac rehabilitation (CR) following cardiac interventions. A total of 108 patients were evaluated at the beginning of their CR, at 6 and 12 months after discharge. Self-report questionnaires were used to assess depression, anxiety, illness perception and work stress at each time stage. Results showed reports of depressive symptoms significantly decreased (p work stress after their RTW. Patients' psychological health and work stress need to be assessed during the CR and should be also carefully monitored after the RTW in order to identify patients' psychological and work-related barriers and facilitate a safe and successful work reintegration. Copyright © 2014 John Wiley & Sons, Ltd.

  10. Measuring Thermal Stress of Dairy Cattle Based on Temperature Humidity Index (THI in Tropical Climate



    Full Text Available Thermal comfort for workers is very important factor to increase their performance, as well as the comfort level of dairy cattle will influence in milk productivity. The purposes of the paper is to measure the level of heat stress and then use the information to design the dairy cattle house for increasing thermal comfort. The research is started with literature review of heat stress and early survey of environment condition e.g. temperature, wind speed and relative humidity. The next step is using the information to determine the temperature humidity index (THI level for dairy cattle with maximum THI = 86 and 84 (moderate stress. The 3D CAD model and Computational Fluid Dynamic (CFD simulation are employed to looking for solution for reducing the discomfort thermal of dairy cattle. A scenario (fan air conditioning to get better condition of thermal comfort have been successfully presented with final THI index = 76 and 78 (mild stress. Finally, the paper shows how to reduce heat stress of cattle house by installation 3 exhaust fans in tropical climate.

  11. Aluminium induced oxidative stress results in decreased mitochondrial biogenesis via modulation of PGC-1α expression.

    Sharma, Deep Raj; Sunkaria, Aditya; Wani, Willayat Yousuf; Sharma, Reeta Kumari; Kandimalla, Ramesh J L; Bal, Amanjit; Gill, Kiran Dip


    The present investigation was carried out to elucidate a possible molecular mechanism related to the effects of aluminium-induced oxidative stress on various mitochondrial respiratory complex subunits with special emphasis on the role of Peroxisome proliferator activated receptor gamma co-activator 1α (PGC-1α) and its downstream targets i.e. Nuclear respiratory factor-1(NRF-1), Nuclear respiratory factor-2(NRF-2) and Mitochondrial transcription factor A (Tfam) in mitochondrial biogenesis. Aluminium lactate (10mg/kgb.wt./day) was administered intragastrically to rats for 12 weeks. After 12 weeks of exposure, we found an increase in ROS levels, mitochondrial DNA oxidation and decrease in citrate synthase activity in the Hippocampus (HC) and Corpus striatum (CS) regions of rat brain. On the other hand, there was a decrease in the mRNA levels of the mitochondrial encoded subunits-NADH dehydrogenase (ND) subunits i.e. ND1, ND2, ND3, Cytochrome b (Cytb), Cytochrome oxidase (COX) subunits i.e. COX1, COX3, ATP synthase (ATPase) subunit 6 along with reduced expression of nuclear encoded subunits COX4, COX5A, COX5B of Electron transport chain (ETC). Besides, a decrease in mitochondrial DNA copy number and mitochondrial content in both regions of rat brain was observed. The PGC-1α was down-regulated in aluminium treated rats along with NRF-1, NRF-2 and Tfam, which act downstream from PGC-1α in aluminium treated rats. Electron microscopy results revealed a significant increase in the mitochondrial swelling, loss of cristae, chromatin condensation and decreases in mitochondrial number in case of aluminium treated rats as compared to control. So, PGC-1α seems to be a potent target for aluminium neurotoxicity, which makes it an almost ideal target to control or limit the damage that has been associated with the defective mitochondrial function seen in neurodegenerative diseases. © 2013.

  12. Dry fracture method for simultaneous measurement of in-situ stress state and material properties

    Serata, S. [Serata Geomechanics, Inc., Richmond, CA (United States); Oka, S.; Kikuchi, S. [JDC Corp., Tokyo (Japan)


    Based on the dry fracture principle, a computerized borehole probe has been developed to measure stress state and material properties, simultaneously. The probe is designed to obtain a series of measurements in a continuing sequence along a borehole length, without any interruptive measures, such as resetting packers, taking indentation of borehole wall, overcoming, etc. The new dry fracture probe for the single fracture method is designed to overcome the difficulties posed by its ancestor which was based on the double fracture method. The accuracy of the single fracture method is confirmed by a close agreement with the theory, FE modeling and laboratory testing.

  13. Combined full field stress and strain measurement methods for granular materials

    Broere W.


    Full Text Available The current paper re-introduces the photoelastic measurement method in experimental geomechanics. A full-field phase stepping polariscope suitable for geomechanical model tests has been developed. Additional constraints on the measurement and mechanical setup arising from geomechanical test conditions are outlined as well as the opportunity to measure the displacement fields in the sample with digital image correlation. The capability of the current setup in retrieving the stress and strain field in a granular material is demonstrated.

  14. A Study on the gas productivity by using Experimental Results of Stress-induced Permeability Change in Coal Seam

    Kang, I. O.; Kim, K. H.; Han, J. M.; Lee, S. M.


    Methane Production from coal has become one of the more interesting practices in recent years to produce hydrocarbons. In the United States in 2005, it is estimated that 11% of all gas produced is from coalbed. The permeability is a measure of the capability of a porous medium to transmit fluid thought a network of microscopic channels. The permeability in coal is a direct function of the cleat volume. Since the volume of cleat changes with effect on the effective stress and sorption characteristics for production duration, the permeability also produces the alteration. Thus, to definitely estimate the gas production ability of the coal, it is essential that we especially understand changing aspects of permeability for production duration. Many researchers suggested the empirical equation to describe the effect of matrix shrinkage and effective stress. However, the past research associated with permeability change in coal focused on experimental results at a certain temperature.In this study, we have investigated the change of the sorption-induced permeability in pressure change with depth, an experimental approach considering temperature influence at the certain depth may be followed. Based on the received core from CBM field, we conducted the experiment both sorption and permeability according to the various pressure and temperatures.Firstly, experiment of the CH4 sorption was performed in the temperature ranged from 59℉ to 113℉ in the pressure ranges from 14.7 psia to 1,299 psia. Ot was found that CH3 isotherms display a normal Langmuir-type behavior from experiment ranges. In order to understand the effect of adsorption of CH4 in the change of sorption-induced permeability, we measured the permeability at the various pressures. When the pressure was increased by 100 psia, the results showed that the permeability alteration rate was 9.7% in reduction. Meanwhile, the permeability change rate was higher for a better affinity gas at lower temperature. Based on

  15. Ultrasonic Measurement of Transient Change in Stress-Strain Property of Radial Arterial Wall Caused by Endothelium-Dependent Vasodilation

    Ikeshita, Kazuki; Hasegawa, Hideyuki; Kanai, Hiroshi


    The endothelial dysfunction is considered to be an initial step of atherosclerosis. Additionally, it was reported that the smooth muscle, which constructs the media of the artery, changes its characteristics owing to atherosclerosis. Therefore, it is essential to develop a method for assessing the regional endothelial function and mechanical property of the arterial wall. There is a conventional technique of measuring the transient change in the diameter of the brachial artery caused by flow-mediated dilation (FMD) after the release of avascularization. For more sensitive and regional evaluation, we developed a method of measuring the change in the elasticity of the radial artery due to FMD. In this study, the transient change in the mechanical property of the arterial wall was further revealed by measuring the stress-strain relationship during each heartbeat. The minute change in the thickness (strain) of the radial arterial wall during a cardiac cycle was measured by the phased tracking method, together with the waveform of blood pressure which was continuously measured with a sphygmometer at the radial artery. The transient change in stress-strain relationship during a cardiac cycle was obtained from the measured changes in wall thickness and blood pressure to show the transient change in instantaneous viscoelasticity. From the in vivo experimental results, the stress-strain relationship shows the hysteresis loop. The slope of the loop decreased owing to FMD, which shows that the elastic modulus decreased, and the increasing area of the loop depends on the ratio of the loss modulus (depends on viscosity) to the elastic modulus when the Voigt model is assumed. These results show a potential of the proposed method for the thorough analysis of the transient change in viscoelasticity due to FMD.

  16. Measuring Stress-dependent Fluid Flow Behavior in Fractured Porous Media

    Huo, Da; Benson, Sally


    Maintaining long-term storage of CO2 is one of the most important factors for selecting the site for a geological CO2 storage project. Nevertheless, it is important to be prepared for possible leakage due to leaking wells or leakage pathways through the seal of a storage reservoir. This research project is motivated by the need to understand unexpected CO2 leakage. The goal of this research is to investigate stress-dependent fracture permeability and relative permeability of CO2/brine systems. Laboratory measurements of fracture permeability and fracture apertures have been made as a function of effective stress. The phenomenon that permeability decreases with effective pressure increase is observed. Due to deformation of the fracture surface during periods with high effective stress, hysteretic behavior of fractured rock permeability is also observed in core flood experiments. A series of experiments are conducted to investigate permeability hysteresis. A single saw-cut fracture is created in the rock sample to simplify the problem and to focus on the fracture itself. Permeability is measured using a high pressure core flood apparatus with X-Ray CT scanning to measure the fracture aperture distributions. Two permeability data sets, including a high permeability fractured Berea Sandstone and a low permeability fractured Israeli Zenifim Formation sandstone, show clear hysteretic behavior in both permeability and fracture aperture in repeated cycles of compression and decompression. Due to closure of the fracture aperture, when a fractured rock is compressed axially, the permeability has an exponential decline with effective pressure, as expected from stress-dependent permeability theory. When the fractured rock is decompressed afterwards, permeability increases, but not along the compression pathway and never returns to the original value. Depending on the nature of the fracture and host rock, permeability can decrease from a factor of 2 to 40. After one or more

  17. Ecologically relevant stress resistance: from microarrays and quantitative trait loci to candidate genes – A research plan and preliminary results using Drosophila as a model organism and climatic and genetic stress as model stresses

    Volker Loeschcke; Jesper G Sørensen; Torsten N Kristensen


    We aim at studying adaptation to genetic and environmental stress and its evolutionary implications at different levels of biological organization. Stress influences cellular processes, individual physiology, genetic variation at the population level, and the process of natural selection. To investigate these highly connected levels of stress effects, it is advisable – if not critical – to integrate approaches from ecology, evolution, physiology, molecular biology and genetics. To investigate the mechanisms of stress resistance, how resistance evolves, and what factors contribute to and constrain its evolution, we use the well-defined model systems of Drosophila species, representing both cosmopolitan species such as D. melanogaster with a known genome map, and more specialized and ecologically well described species such as the cactophilic D. buzzatii. Various climate-related stresses are used as model stresses including desiccation, starvation, cold and heat. Genetic stress or genetic load is modelled by studying the consequences of inbreeding, the accumulation of (slightly) deleterious mutations, hybridization or the loss of genetic variability. We present here a research plan and preliminary results combining various approaches: molecular techniques such as microarrays, quantitative trait loci (QTL) analyses, quantitative PCR, ELISA or Western blotting are combined with population studies of resistance to climatic and genetic stress in natural populations collected across climatic gradients as well as in selection lines maintained in the laboratory.

  18. Stress urinary incontinence and posterior bladder suspension defects. Results of vaginal repair versus Burch colposuspension

    Thunedborg, P; Fischer-Rasmussen, W; Jensen, S B


    Vaginal repair has been recommended in cases of stress urinary incontinence and posterior bladder suspension defect diagnosed by colpocysto-urethrography. Thirty-eight women with stress urinary incontinence and posterior suspension defect have been treated. First, 19 women underwent a vaginal...... after 6 months or at the long-term follow-up. A significantly smaller frequency of genital prolapse was found in the colposuspension group at long-term follow-up. No side effects such as frequency, urgency or bacteriuria were evident in the group treated by colposuspension. With reservation to the non...

  19. Cognitive-Behavioral Treatment of Posttraumatic Stress in Patients With Implantable Cardioverter Defibrillators: Results From a Randomized Controlled Trial.

    Ford, Jessica; Rosman, Lindsey; Wuensch, Karl; Irvine, Jane; Sears, Samuel F


    Approximately 20% of patients with implantable cardioverter defibrillators (ICDs) suffer from posttraumatic stress disorder (PTSD) due to a history of cardiac arrest, device implantation, and ICD shock. There has been very little examination of treatment of PTSD symptoms in these patients. This study evaluated the effect of a specific cognitive-behavioral therapy (CBT) intervention for ICD patients with high levels of PTSD symptoms: a manualized program consisting of 8 telephone sessions with a trained counselor, a patient education book, and a stress management procedure on compact disc. Participants were 193 ICD patients, who were randomized to CBT or usual cardiac care (UCC) who completed self-report surveys at the time of recruitment and 6 and 12 months after initial measurement. Previous publication on the primary research evaluation questions reported that the CBT condition resulted in greater improvement on PTSD and depression symptoms than the UCC for the general population of ICD patients, but did not evaluate the effect on those with elevated symptoms of PTSD. The authors conducted secondary analyses of the effect of treatment on high and low PTSD symptom groups based on a cutoff for the Impact of Event Scale-Revised (Weiss & Marmar, 1997). Participants in the CBT group who had high symptoms experienced significantly greater symptom reduction from baseline to 12 months (d = 2.44, p = .021) than the UCC group (d = 1.12). Participants with low symptoms had small reductions regardless of group assignment (d = 0.16, p = .031). ICD-focused CBT was sufficient to produce a large, statistically significant reduction in PTSD symptoms in ICD patients with indications for treatment.

  20. A study on factors of dissatisfaction and stress of the blacksmiths resulting from the organizational culture in the surgical instrument industry of India

    Tirthankar Ghosh


    Full Text Available Background: It is important to understand what motivates workers and the extent to which the organization and other contextual variables satisfy them. The aim of the study was to determine factors of dissatisfaction resulting from the organizational culture among the blacksmiths involved in the surgical instrument industry. Materials and Methods: Fifty male surgical blacksmiths each of the skilled and unskilled groups of the forging section were selected. Organizational Role Stress Scale was used to measure the individuals′ role stress and several forms of conflict within an organization. Also, the organizational culture and personal involvement in an organization was measured among the surgical blacksmiths. Results: The mean score for total role stress for Skilled was 71.7 and for unskilled was 77.2. The most frequent type of organizational culture was reported to be hierarchy, both by skilled and unskilled surgical blacksmiths, followed by market and clan culture. Conclusion: This study shows that the skilled surgical blacksmiths have lower level of stress and conflicts in comparison with unskilled surgical blacksmiths. Both skilled and unskilled surgical blacksmiths estimated their level of personal involvement as low and indicated insufficient involvement in work teams. The satisfaction of the employees with their status and role in the organizational culture was also poor for both skilled and unskilled surgical blacksmiths.