Sample records for strain gage based

  1. Internally Mounting Strain Gages (United States)

    Jett, J. R., Jr.


    Technique for mounting strain gages inside bolt or cylinder simultaneously inserts gage, attached dowel segment, and length of expandable tubing. Expandable tubing holds gage in place while adhesive cures, assuring even distribution of pressure on gage and area gaged.

  2. Strain gage based determination of mixed mode SIFs (United States)

    Murthy, K. S. R. K.; Sarangi, H.; Chakraborty, D.


    Accurate determination of mixed mode stress intensity factors (SIFs) is essential in understanding and analysis of mixed mode fracture of engineering components. Only a few strain gage determination of mixed mode SIFs are reported in literatures and those also do not provide any prescription for radial locations of strain gages to ensure accuracy of measurement. The present investigation experimentally demonstrates the efficacy of a proposed methodology for the accurate determination of mixed mode I/II SIFs using strain gages. The proposed approach is based on the modified Dally and Berger's mixed mode technique. Using the proposed methodology appropriate gage locations (optimal locations) for a given configuration have also been suggested ensuring accurate determination of mixed mode SIFs. Experiments have been conducted by locating the gages at optimal and non-optimal locations to study the efficacy of the proposed approach. The experimental results from the present investigation show that highly accurate SIFs (0.064%) can be determined using the proposed approach if the gages are located at the suggested optimal locations. On the other hand, results also show the very high errors (212.22%) in measured SIFs possible if the gages are located at non-optimal locations. The present work thus clearly substantiates the importance of knowing the optimal locations of the strain gages apriori in accurate determination of SIFs.

  3. Development of high temperature strain gage, (5)

    International Nuclear Information System (INIS)

    Yuuki, Hiroshi; Kobayashi, Yukio; Kanai, Kenji; Yamaura, Yoshio


    Development and improvement of resistance wire type strain gages usable for experimental measurement of thermal strains generated at high temperature in various structures and equipments that consist of a Fast Breeder Reactor have been carried out, and various characteristics of the strain gages have been investigated. Based on the results obtained up to now, development and research of this time mainly aim to improve strain and fatigue characteristics. As the results, characteristics of strain gages with sensing elements of nichrome V are improved, specifically mechanical hysteresis is decreased, strain limit is increased, etc. Also, improvement is recognized in thermal output, and it becomes clear that dummy gages work effectively. However, a filling method of MgO and an inserting method of active-dummy elements are selected as primary objects to improve strain characteristics, and many hours are taken for these objects, so confirmations of characteristics of platinum-tungsten strain gages, strain sensing elements of which are troublesome to produce, have not been completely done, though the performance of the gages has been improved in several points. As to nichrome V strain gages, there is a fair prospect of obtaining ones, specifications of which are quite close to the goal, though problems in manufacturing technics remain for future. As to platinum-tungsten strain gages, it is expected that similar strain gages to nichrome V are obtainable by improvement in manufacturing of sensing elements. (auth.)

  4. Investigation of factors affecting the calibration of strain gage based transducers (''Goodzeit gages'') for SSC magnets

    International Nuclear Information System (INIS)

    Davidson, M.; Gilbertson, A.; Dougherty, M.


    These transducers are designed to measure stresses on SSC collared coils. They are individually calibrated with a bonded ten-stack of SSC inner coil cable by applying a known load and reading corresponding output from the gages. The transducer is supported by a notched ''backing plate'' that allows for bending of the gage beam during calibration or in use with an actual coil. Several factors affecting the calibration and use of the transducers are: the number of times a ''backing plate'' is used, the similarities or difficulties between bonded ten-stacks, and the differences between the ten-stacks and the coil they represent. The latter is probably the most important because a calibration curve is a model of how a transducer should react within a coil. If the model is wrong, the calibration curve is wrong. Information will be presented regarding differences in calibrations between Brookhaven National Labs (also calibrating these transducers) and Fermilab -- what caused these differences, the investigation into the differences between coils and ten-stacks and how they relate to transducer calibration, and some suggestions for future calibrations

  5. Properties of strain gages at cryogenic temperature

    International Nuclear Information System (INIS)

    Shibata, Nobuo; Fujiyoshi, Toshimitsu.


    At the time of developing superconduction generators, the stress measurement for rotor parts is required to grasp the safety and performance of the rotor at cryogenic temperature, which is cooled with liquid helium. In case of carrying out the stress measurement with strain gages, the problems are as follows. The strain gages and lead wires are exposed to cryogenic temperature from 4 to 10 K and strong magnetic field of about 3T, and subjected to high centrifugal acceleration of about 500G. In order to establish the techniques of the stress measurement under such conditions, the adhesives and damp-proof coatings for strain gages and strain gages themselves in Japan and foreign countries were examined on the properties at cryogenic temperature. As for the properties of strain gages, mainly the apparent strain owing to temperature change was investigated, and the change of the gage factors was studies only at liquid nitrogen temperature. The stress measurement with strain gages at low temperature had been studied in detail down to liquid nitrogen temperature concerning LNG tanks. The experimental apparatus, the samples, the testing methods and the test results of cooling tests on adhesives and damp-proof coatings, and the temperature characteristics of strain gages are reported. The usable adhesives and coatings were found, and correction by accurate temperature measurement is required for apparent strain. (Kako, I.)

  6. Accelerometer and strain gage evaluation

    International Nuclear Information System (INIS)

    Ammerman, D.J.; Madsen, M.M.; Uncapher, W.L.; Stenberg, D.R.; Bronowski, D.R.


    This document describes the method developed by Sandia National Laboratories (SNL) to evaluate transducer used in the design certification testing of nuclear material shipping packages. This testing project was performed by SNL for the Office of Civilian Radioactive Waste Management (OCRWM). This evaluation is based on the results of tests conducted to measure ruggedness, failure frequency, repeatability, and manufacturers' calibration data under both field and laboratory conditions. The results of these tests are provided and discussed. The transducer were selected for testing by surveying cask contractors and testing facilities. Important insights relating to operational characteristics of accelerometer types were gained during field testing. 11 refs., 105 figs., 16 tabs

  7. Evaluation results of the 700 deg C Chinese strain gages (United States)

    Hobart, H. F.


    There is a continuing interest and need for resistance strain gages capable of making static strain measurements on components located in the hot section of gas turbine engines. A paper by Tsen-tai Wu describes the development and evaluation of high temperature gauges fabricated from specially developed Fe-Cr-Al-V-Ti-Y alloy wire. Several of these gages and a quantity of P12-2 ceramic adhesive were purchased for evaluation. Nine members of the aircraft turbine engine community were invited to participate in an evaluation of these gages. Each participant was sent one strain gage, a small amount of ceramic adhesive, instructions for mounting the gage on a test beam, and a set of suggestions for the experiment. Data on gage factor variation with temperature, apparent strain, and drift are discussed.

  8. Theory and Practice of Shear/Stress Strain Gage Hygrometry (United States)

    Shams, Qamar A.; Fenner, Ralph L.


    Mechanical hygrometry has progressed during the last several decades from crude hygroscopes to state-of-the art strain-gage sensors. The strain-gage devices vary from different metallic beams to strain-gage sensors using cellulose crystallite elements, held in full shear restraint. This old technique is still in use but several companies are now actively pursuing development of MEMS miniaturized humidity sensors. These new sensors use polyimide thin film for water vapor adsorption and desorption. This paper will provide overview about modern humidity sensors.

  9. Evaluation test on stability of high temperature strain gage

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Toshimi (Kyowa Electronic Instruments Co. Ltd., Tokyo (Japan)); Ito, Haruhiko; Tanaka, Isao; Komori, Yoshihiro


    This report deals with the results on a stability test of high temperature strain gage which is utilized for development of the Stethoscope for OGL - 1 Components in Elevated Temperature Services (ab. SOCETS). The test has proved that the weldable strain gage (KHC - 20 - G5) exhibits excellent stability at 500/sup 0/C during 3000 to 4000 hours service and can be applied sufficiently to evaluate integrity of OGL - 1 high temperature pipings and others.

  10. Evaluation test on stability of high temperature strain gage

    International Nuclear Information System (INIS)

    Sato, Toshimi; Ito, Haruhiko; Tanaka, Isao; Komori, Yoshihiro.


    This report deals with the results on a stability test of high temperature strain gage which is utilized for development of the Stethoscope for OGL - 1 Components in Elevated Temperature Services (ab. SOCETS). The test has proved that the weldable strain gage (KHC - 20 - G5) exhibits excellent stability at 500 0 C during 3000 to 4000 hours service and can be applied sufficiently to evaluate integrity of OGL - 1 high temperature pipings and others. (author)

  11. Methodology to measure strains at high temperatures using electrical strain gages with free filaments

    International Nuclear Information System (INIS)

    Atanazio Filho, Nelson N.; Gomes, Paulo T. Vida; Scaldaferri, Denis H.B.; Silva, Luiz L. da; Rabello, Emerson G.; Mansur, Tanius R.


    An experimental methodology used for strains measuring at high temperatures is show in this work. In order to do the measurements, it was used electric strain gages with loose filaments attached to a stainless steel 304 beam with specific cements. The beam has triangular shape and a constant thickness, so the strain is the same along its length. Unless the beam surface be carefully prepared, the strain gage attachment is not efficient. The showed results are for temperatures ranging from 20 deg C to 300 deg C, but the experimental methodology could be used to measure strains at a temperature up to 900 deg C. Analytical calculations based on solid mechanics were used to verify the strain gage electrical installation and the measured strains. At a first moment, beam deformations as a temperature function were plotted. After that, beam deformations with different weighs were plotted as a temperature function. The results shown allowed concluding that the experimental methodology is trustable to measure strains at temperatures up to 300 deg C. (author)

  12. Evaluation test of high temperature strain gages used in a stethoscope for OGL-1 components in an elevated temperature service

    International Nuclear Information System (INIS)

    Sato, Toshimi; Tanaka, Isao; Komori, Yoshihiro; Suzuki; Toshiaki.


    The stethoscope for OGL-1 components in a elevated temperature service (SOCETS) is a measuring system of evaluation integrity of structures for high temperature pipings during operations of Japan Material Testing Reactor. This paper is described about the results on fundamental performance on high temperature strain gages. From their test results that have been based on correlation of temperature-timestrain factors, it became clear that two weldable strain gages and a capacitance strain gage were available for strain measurements of OGL-1 components. (author)

  13. Evaluation test of high temperature strain gages used in a stethoscope for OGL-1 components in an elevated temperature service

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Toshimi (Kyowa Electronic Inst. Co. Ltd. (Japan)); Tanaka, Isao; Komori, Yoshihiro; Suzuki; Toshiaki


    The stethoscope for OGL-1 components in a elevated temperature service (SOCETS) is a measuring system of evaluation integrity of structures for high temperature pipings during operations of Japan Material Testing Reactor. This paper is described about the results on fundamental performance on high temperature strain gages. From their test results that have been based on correlation of temperature-timestrain factors, it became clear that two weldable strain gages and a capacitance strain gage were available for strain measurements of OGL-1 components.

  14. A new strain gage method for measuring the contractile strain ratio of Zircaloy tubing

    International Nuclear Information System (INIS)

    Hwang, S.K.; Sabol, G.P.


    An improved strain gage method for determining the contractile strain ratio (CSR) of Zircaloy tubing was developed. The new method consists of a number of load-unload cyclings at approximately 0.2% plastic strain interval. With this method the CSR of Zircaloy-4 tubing could be determined accurately because it was possible to separate the plastic strains from the elastic strain involvement. The CSR values determined by use of the new method were in good agreement with those calculated from conventional post-test manual measurements. The CSR of the tubing was found to decrease with the amount of deformation during testing because of uneven plastic flow in the gage section. A new technique of inscribing gage marks by use of a YAG laser is discussed. (orig.)

  15. Nickel--chromium strain gages for cryogenic stress analysis of superconducting structures in high magnetic fields

    International Nuclear Information System (INIS)



    Magnetoresistance measurements of strain gages were made. The magnitude and variation of the magnetoresistance of a large number of strain gages were measured for the following conditions: (1) dc magnetic fields up to 12 T, (2) three orthogonal field directions, (3) increasing and decreasing fields, (4) a wide range of strain levels, and (5) liquid helium temperature

  16. Nickel--chromium strain gages for cryogenic stress analysis of superconducting structures in high magnetic fields

    International Nuclear Information System (INIS)

    Freynik, H.S. Jr.; Roach, D.R.; Deis, D.W.; Hirzel, D.G.


    Evaluation and calibration measurements were performed on commercial nickel-chromium metal-foil strain gages in a high-magnetic-field (12 T), liquid-helium (4.2 K) environment. The purpose was to fully characterize strain gages for use at cryogenic temperatures in high magnetic fields. In this study, the magnetoresistance of a number of strain gages was measured in three orthogonal directions at mechanical strain levels to 8900 μm/m. As a result, a unique calibration curve was defined for magnetoresistance strain errors that is independent of strain level and field direction to 12 T at 4.2 K. A current strain-gage application is the measurement of superconductor mechanical properties. These gages will soon be used in the stress analysis of superconducting fusion magnets during cooldown from ambient temperatures and during operation at 4.2 K with magnetic fields to 12 T

  17. Utilizing Photogrammetry and Strain Gage Measurement to Characterize Pressurization of an Inflatable Module (United States)

    Valle, Gerard D.; Selig, Molly; Litteken, Doug; Oliveras, Ovidio


    This paper documents the integration of a large hatch penetration into an inflatable module. This paper also documents the comparison of analytical load predictions with measured results utilizing strain measurement. Strain was measured by utilizing photogrammetric measurement and through measurement obtained from strain gages mounted to selected clevises that interface with the structural webbings. Bench testing showed good correlation between strain measurement obtained from an extensometer and photogrammetric measurement especially after the fabric has transitioned through the low load/high strain region of the curve. Test results for the full-scale torus showed mixed results in the lower load and thus lower strain regions. Overall strain, and thus load, measured by strain gages and photogrammetry tracked fairly well with analytical predictions. Methods and areas of improvements are discussed.

  18. Thermal expansion and magnetostriction measurements at cryogenic temperature using the strain gage method (United States)

    Wang, Wei; Liu, Huiming; Huang, Rongjin; Zhao, Yuqiang; Huang, Chuangjun; Guo, Shibin; Shan, Yi; Li, Laifeng


    Thermal expansion and magnetostriction, the strain responses of a material to temperature and a magnetic field, especially properties at low temperature, are extremely useful to study electronic and phononic properties, phase transitions, quantum criticality, and other interesting phenomena in cryogenic engineering and materials science. However, traditional dilatometers cannot provide magnetic field and ultra low temperature (<77 K) environment easily. This paper describes the design and test results of thermal expansion and magnetostriction at cryogenic temperature using the strain gage method based on a Physical Properties Measurements System (PPMS). The interfacing software and automation were developed using LabVIEW. The sample temperature range can be tuned continuously between 1.8 K and 400 K. With this PPMS-aided measuring system, we can observe temperature and magnetic field dependence of the linear thermal expansion of different solid materials easily and accurately.

  19. Improved Regression Analysis of Temperature-Dependent Strain-Gage Balance Calibration Data (United States)

    Ulbrich, N.


    An improved approach is discussed that may be used to directly include first and second order temperature effects in the load prediction algorithm of a wind tunnel strain-gage balance. The improved approach was designed for the Iterative Method that fits strain-gage outputs as a function of calibration loads and uses a load iteration scheme during the wind tunnel test to predict loads from measured gage outputs. The improved approach assumes that the strain-gage balance is at a constant uniform temperature when it is calibrated and used. First, the method introduces a new independent variable for the regression analysis of the balance calibration data. The new variable is designed as the difference between the uniform temperature of the balance and a global reference temperature. This reference temperature should be the primary calibration temperature of the balance so that, if needed, a tare load iteration can be performed. Then, two temperature{dependent terms are included in the regression models of the gage outputs. They are the temperature difference itself and the square of the temperature difference. Simulated temperature{dependent data obtained from Triumph Aerospace's 2013 calibration of NASA's ARC-30K five component semi{span balance is used to illustrate the application of the improved approach.

  20. Utilizing Photogrammetry and Strain Gage Measurement to Characterize Pressurization of Inflatable Modules (United States)

    Mohammed, Anil


    This paper focuses on integrating a large hatch penetration into inflatable modules of various constructions. This paper also compares load predictions with test measurements. The strain was measured by utilizing photogrammetric methods and strain gages mounted to select clevises that interface with the structural webbings. Bench testing showed good correlation between strain data collected from an extensometer and photogrammetric measurements, even when the material transitioned from the low load to high load strain region of the curve. The full-scale torus design module showed mixed results as well in the lower load and high strain regions. After thorough analysis of photogrammetric measurements, strain gage measurements, and predicted load, the photogrammetric measurements seem to be off by a factor of two.

  1. Indium tin oxide thin film strain gages for use at elevated temperatures (United States)

    Luo, Qing

    A robust ceramic thin film strain gage based on indium-tin-oxide (ITO) has been developed for static and dynamic strain measurements in advanced propulsion systems at temperatures up to 1400°C. These thin film sensors are ideally suited for in-situ strain measurement in harsh environments such as those encountered in the hot sections of gas turbine engines. A novel self-compensation scheme was developed using thin film platinum resistors placed in series with the active strain element (ITO) to minimize the thermal effect of strain or apparent strain. A mathematical model as well as design rules were developed for the self-compensated circuitry using this approach and close agreement between the model and actual static strain results has been achieved. High frequency dynamic strain tests were performed at temperatures up to 500°C and at frequencies up to 2000Hz to simulate conditions that would be encountered during engine vibration fatigue. The results indicated that the sensors could survive extreme test conditions while maintaining sensitivity. A reversible change in sign of the piezoresistive response from -G to +G was observed in the vicinity of 950°C, suggesting that the change carrier responsible for conduction in the ITO gage had been converted from a net "n-carrier" to a net "p-carrier" semiconductor. Electron spectroscopy for chemical analysis (ESCA) of the ITO films suggested they experienced an interfacial reaction with the Al2O3 substrate at 1400°C. It is likely that oxygen uptake from the substrate is responsible for stabilizing the ITO films to elevated temperatures through the interfacial reaction. Thermo gravimetric analysis of ITO films on alumina at elevated temperatures showed no sublimation of ITO films at temperature up to 1400°C. The surface morphology of ITO films heated to 800, 1200 and 1400°C were also evaluated by atomic force microscopy (AFM). A linear current-voltage (I--V) characteristic indicated that the contact interface

  2. Review of Trackside Monitoring Solutions: From Strain Gages to Optical Fibre Sensors

    Directory of Open Access Journals (Sweden)

    Georges Kouroussis


    Full Text Available A review of recent research on structural monitoring in railway industry is proposed in this paper, with a special focus on stress-based solutions. After a brief analysis of the mechanical behaviour of ballasted railway tracks, an overview of the most common monitoring techniques is presented. A special attention is paid on strain gages and accelerometers for which the accurate mounting position on the track is requisite. These types of solution are then compared to another modern approach based on the use of optical fibres. Besides, an in-depth discussion is made on the evolution of numerical models that investigate the interaction between railway vehicles and tracks. These models are used to validate experimental devices and to predict the best location(s of the sensors. It is hoped that this review article will stimulate further research activities in this continuously expanding field.

  3. Thermal expansion measurement of turbine and main steam piping by using strain gages in power plants

    International Nuclear Information System (INIS)

    Na, Sang Soo; Chung, Jae Won; Bong, Suk Kun; Jun, Dong Ki; Kim, Yun Suk


    One of the domestic co-generation plants have undergone excessive vibration problems of turbine attributed to external force for years. The root cause of turbine vibration may be shaft alignment problem which sometimes is changed by thermal expansion and external force, even if turbine technicians perfectly performed it. To evaluate the alignment condition from plant start-up to full load, a strain measurement of turbine and main steam piping subjected to thermal loading is monitored by using strain gages. The strain gages are bonded on both bearing housing adjusting bolts and pipe stoppers which installed in the x-direction of left-side main steam piping near the turbine inlet in order to monitor closely the effect of turbine under thermal deformation of turbine casing and main steam piping during plant full load. Also in situ load of constant support hangers in main steam piping system is measured by strain gages and its results are used to rebalance the hanger rod load. Consequently, the experimental stress analysis by using strain gages turns out to be very useful tool to diagnose the trouble and failures of not only to stationary components but to rotating machinery in power plants

  4. A Dual-Range Strain Gage Weighing Transducer Employing Automatic Switching (United States)

    Rodger A. Arola


    Describes a dual-range strain gage transducer which has proven to be an excellent weight-sensing device for weighing trees and tree-length logs; discusses basic principals of the design and operation; and shows that a single transducer having two sensitivity ranges with automatic internal switching can sense weight with good repeatability and that one calibration curve...

  5. Suitability of Strain Gage Sensors for Integration into Smart Sport Equipment: A Golf Club Example. (United States)

    Umek, Anton; Zhang, Yuan; Tomažič, Sašo; Kos, Anton


    Wearable devices and smart sport equipment are being increasingly used in amateur and professional sports. Smart sport equipment employs various sensors for detecting its state and actions. The correct choice of the most appropriate sensor(s) is of paramount importance for efficient and successful operation of sport equipment. When integrated into the sport equipment, ideal sensors are unobstructive, and do not change the functionality of the equipment. The article focuses on experiments for identification and selection of sensors that are suitable for the integration into a golf club with the final goal of their use in real time biofeedback applications. We tested two orthogonally affixed strain gage (SG) sensors, a 3-axis accelerometer, and a 3-axis gyroscope. The strain gage sensors are calibrated and validated in the laboratory environment by a highly accurate Qualisys Track Manager (QTM) optical tracking system. Field test results show that different types of golf swing and improper movement in early phases of golf swing can be detected with strain gage sensors attached to the shaft of the golf club. Thus they are suitable for biofeedback applications to help golfers to learn repetitive golf swings. It is suggested that the use of strain gage sensors can improve the golf swing technical error detection accuracy and that strain gage sensors alone are enough for basic golf swing analysis. Our final goal is to be able to acquire and analyze as many parameters of a smart golf club in real time during the entire duration of the swing. This would give us the ability to design mobile and cloud biofeedback applications with terminal or concurrent feedback that will enable us to speed-up motor skill learning in golf.

  6. Evaluation of metal-foil strain gages for cryogenic application in magnetic fields

    International Nuclear Information System (INIS)

    Freynik, H.S. Jr.; Roach, D.R.; Deis, D.W.; Hirzel, D.G.


    The requirement for the design and construction of large superconducting magnet systems for fusion research has raised a number of new questions regarding the properties of composite superconducting conductors. One of these, the effect of mechanical stress on the current-carrying capacity of Nb 3 Sn, is of major importance in determining the feasibility of constructing large magnets with this material. A typical experiment for determining such data involves the measurement of critical current versus magnetic field while the conductor is being mechanically strained to various degrees. Techniques are well developed for the current and field measurements, but much less so for the accurate measurement of strain at liquid-helium temperature in a high magnetic field. A study was made of commercial, metal-foil strain gages for use under these conditions. The information developed can also be applied to the use of strain gages as diagnostic tools in superconducting magnets

  7. Wireless Zigbee strain gage sensor system for structural health monitoring (United States)

    Ide, Hiroshi; Abdi, Frank; Miraj, Rashid; Dang, Chau; Takahashi, Tatsuya; Sauer, Bruce


    A compact cell phone size radio frequency (ZigBee) wireless strain measurement sensor system to measure the structural strain deformation was developed. The developed system provides an accurate strain measurement data stream to the Internet for further Diagnostic and Prognostic (DPS) correlation. Existing methods of structural measurement by strain sensors (gauges) do not completely satisfy problems posed by continuous structural health monitoring. The need for efficient health monitoring methods with real-time requirements to bidirectional data flow from sensors and to a commanding device is becoming critical for keeping our daily life safety. The use of full-field strain measurement techniques could reduce costly experimental programs through better understanding of material behavior. Wireless sensor-network technology is a monitoring method that is estimated to grow rapidly providing potential for cost savings over traditional wired sensors. The many of currently available wireless monitoring methods have: the proactive and constant data rate character of the data streams rather than traditional reactive, event-driven data delivery; mostly static node placement on structures with limited number of nodes. Alpha STAR Electronics' wireless sensor network system, ASWN, addresses some of these deficiencies, making the system easier to operate. The ASWN strain measurement system utilizes off-the-shelf sensors, namely strain gauges, with an analog-to-digital converter/amplifier and ZigBee radio chips to keep cost lower. Strain data is captured by the sensor, converted to digital form and delivered to the ZigBee radio chip, which in turn broadcasts the information using wireless protocols to a Personal Data Assistant (PDA) or Laptop/Desktop computers. From here, data is forwarded to remote computers for higher-level analysis and feedback using traditional cellular and satellite communication or the Ethernet infrastructure. This system offers a compact size, lower cost

  8. Wind Tunnel Strain-Gage Balance Calibration Data Analysis Using a Weighted Least Squares Approach (United States)

    Ulbrich, N.; Volden, T.


    A new approach is presented that uses a weighted least squares fit to analyze wind tunnel strain-gage balance calibration data. The weighted least squares fit is specifically designed to increase the influence of single-component loadings during the regression analysis. The weighted least squares fit also reduces the impact of calibration load schedule asymmetries on the predicted primary sensitivities of the balance gages. A weighting factor between zero and one is assigned to each calibration data point that depends on a simple count of its intentionally loaded load components or gages. The greater the number of a data point's intentionally loaded load components or gages is, the smaller its weighting factor becomes. The proposed approach is applicable to both the Iterative and Non-Iterative Methods that are used for the analysis of strain-gage balance calibration data in the aerospace testing community. The Iterative Method uses a reasonable estimate of the tare corrected load set as input for the determination of the weighting factors. The Non-Iterative Method, on the other hand, uses gage output differences relative to the natural zeros as input for the determination of the weighting factors. Machine calibration data of a six-component force balance is used to illustrate benefits of the proposed weighted least squares fit. In addition, a detailed derivation of the PRESS residuals associated with a weighted least squares fit is given in the appendices of the paper as this information could not be found in the literature. These PRESS residuals may be needed to evaluate the predictive capabilities of the final regression models that result from a weighted least squares fit of the balance calibration data.

  9. Iterative Strain-Gage Balance Calibration Data Analysis for Extended Independent Variable Sets (United States)

    Ulbrich, Norbert Manfred


    A new method was developed that makes it possible to use an extended set of independent calibration variables for an iterative analysis of wind tunnel strain gage balance calibration data. The new method permits the application of the iterative analysis method whenever the total number of balance loads and other independent calibration variables is greater than the total number of measured strain gage outputs. Iteration equations used by the iterative analysis method have the limitation that the number of independent and dependent variables must match. The new method circumvents this limitation. It simply adds a missing dependent variable to the original data set by using an additional independent variable also as an additional dependent variable. Then, the desired solution of the regression analysis problem can be obtained that fits each gage output as a function of both the original and additional independent calibration variables. The final regression coefficients can be converted to data reduction matrix coefficients because the missing dependent variables were added to the data set without changing the regression analysis result for each gage output. Therefore, the new method still supports the application of the two load iteration equation choices that the iterative method traditionally uses for the prediction of balance loads during a wind tunnel test. An example is discussed in the paper that illustrates the application of the new method to a realistic simulation of temperature dependent calibration data set of a six component balance.

  10. Design of membrane pressure indicators with strain gages

    International Nuclear Information System (INIS)

    Haberzettl, G.


    A special type of pressure indicators, more or less well known under the name of 'membrane pressure indicators' is dealt with. In principle, they consist of a pipe socket which is open at one end and sealed by the 'membrane' at the other end. In case of internal pressure from the open side, the membrane will begin to arch. This arch, which is proportional to the internal pressure, is measured by suitable methods. A special form of strain ganges, so-called 'membrane pressure roses' have turned out to be particularly suitable here. The article gives general guidelines for the construction of membrane pressure indicators. (orig./HT) [de

  11. Stress Measurement around a Circular Role in a Cantilever Beam under Bending Moment Using Strain Gage and Reflective Photoelasticity

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Tae Hyun; Park, Tae Geun; Yang, Min Bok [Kunsan National University, Gunsan (Korea, Republic of)


    It is necessary to study on the stress concentration experimentally, which is the main reason to avoid mechanical dilapidation and failure, when designing a mechanical structure. Stress concentration factor of a specimen of cantilever beam with a circular hole in the center was measured using both strain gage and photoelastic methods in this paper. In strain-gage measurement, three strain gages along the line near a hole of the specimen were installed and maximum strain was extrapolated from three measurements. In photoelastic measurement, two methods were employed. First, the Babinet-Soleil compensation method was used to measure the maximum strain. Secondly, photoelastic 4-step phase shilling method was applied to observe the strain distribution around the hole. Measurements obtained by different experiments were comparable within the range of experimental error

  12. Stress Measurement around a Circular Role in a Cantilever Beam under Bending Moment Using Strain Gage and Reflective Photoelasticity

    International Nuclear Information System (INIS)

    Baek, Tae Hyun; Park, Tae Geun; Yang, Min Bok


    It is necessary to study on the stress concentration experimentally, which is the main reason to avoid mechanical dilapidation and failure, when designing a mechanical structure. Stress concentration factor of a specimen of cantilever beam with a circular hole in the center was measured using both strain gage and photoelastic methods in this paper. In strain-gage measurement, three strain gages along the line near a hole of the specimen were installed and maximum strain was extrapolated from three measurements. In photoelastic measurement, two methods were employed. First, the Babinet-Soleil compensation method was used to measure the maximum strain. Secondly, photoelastic 4-step phase shilling method was applied to observe the strain distribution around the hole. Measurements obtained by different experiments were comparable within the range of experimental error

  13. Strain-gage signal-conditioning system for use in the LCP

    International Nuclear Information System (INIS)

    Ellis, J.F.; Walstrom, P.L.


    A strain-gage signal-conditioning system, providing wide-band noise rejection and isolation from high voltages that occur during emergency coil discharges, has been developed and tested. The multichannel system combines double-shielded transformers, neutralizing networks, and bandpass filters (with commercial 3-kHz carrier amplifier modules to isolate the strain gages to 5000 V) eliminate thermoelectric effects, and provide a signal bandwidth of 200 Hz. Common-mode interference occurs primarily as a result of beat-note effects between the carrier and the superimposed noise at frequencies near the odd harmonics of the carrier. The common-mode rejection of the test circuit was measured to be 120 dB for noise at 2750 and 3250 Hz, 135 dB at 3 kHz, and 135 dB and better at the odd harmonics of 9 kHz and above. The system has been successfully used in strain measurements on the toroidal field coils of the ISX-B tokamak and will be used in the Large Coil Test Facility to monitor strains in the energized coil conductors

  14. Problems in use and security of measurement of high temperature strain gages at various temperature limits up to 10000C

    International Nuclear Information System (INIS)

    Ziegler, K.


    The examples given show the quality and use of manufacturers' data for a series of behaviour criteria for strain gages in the high temperature region. These results should not only be regarded critically. The manufacturer must appreciate that the very costly programme of investigations on the users' side represents a product development for large parts for the manufacturer of the strain gauges. It would therefore be desirable if these considerations were to initiate investigations on the manufacturer's part, in order to clear up the problematic are of the use of strain gages in the high temperature field, in order to provide the customer with more reliable and better strain gage characteristics for very expensive high temperature strain measurements. (orig.) [de

  15. Quantum dots as mineral- and matrix-specific strain gages for bone biomechanical studies (United States)

    Zhu, Peizhi; Xu, Jiadi; Morris, Michael; Ramamoorthy, Ayyalusamy; Sahar, Nadder; Kohn, David


    We report the use of quantum dots (Qdots) as strain gages in the study of bone biomechanics using solid state nuclear magnetic resonance (NMR) spectroscopy. We have developed solid state NMR sample cells for investigation of deformations of bone tissue components at loads up to several Mega Pascal. The size constraints of the NMR instrumentation limit the bone specimen diameter and length to be no greater than 2-3 mm and 30 mm respectively. Further, magic angle spinning (MAS) solid state NMR experiments require the use of non-metallic apparatus that can be rotated at kilohertz rates. These experimental constraints preclude the use of standard biomechanical measurement systems. In this paper we explore the use of quantum dot center of gravity measurement as a strain gage technology consistent with the constraints of solid state NMR. We use Qdots that bind calcium (625 nm emission) and collagen (705 nm emission) for measurement of strain in these components. Compressive loads are applied to a specimen in a cell through a fine pitch screw turned with a mini-torque wrench. Displacement is measured as changes in the positions of arrays of quantum dots on the surface of a specimen. Arrays are created by spotting the specimen with dilute suspensions of Qdots. Mineral labeling is achieved with 705 nm carboxylated dots and matrix labeling with 565 nm quantum dots conjugated to collagen I antibodies. After each load increment the new positions of the quantum dots are measured by fluorescence microscopy. Changes in Qdot center of gravity as a function of applied load can be measured with submicron accuracy.

  16. Flexible Riser Monitoring Using Hybrid Magnetic/Optical Strain Gage Techniques through RLS Adaptive Filtering

    Directory of Open Access Journals (Sweden)

    Daniel Pipa


    Full Text Available Flexible riser is a class of flexible pipes which is used to connect subsea pipelines to floating offshore installations, such as FPSOs (floating production/storage/off-loading unit and SS (semisubmersible platforms, in oil and gas production. Flexible risers are multilayered pipes typically comprising an inner flexible metal carcass surrounded by polymer layers and spiral wound steel ligaments, also referred to as armor wires. Since these armor wires are made of steel, their magnetic properties are sensitive to the stress they are subjected to. By measuring their magnetic properties in a nonintrusive manner, it is possible to compare the stress in the armor wires, thus allowing the identification of damaged ones. However, one encounters several sources of noise when measuring electromagnetic properties contactlessly, such as movement between specimen and probe, and magnetic noise. This paper describes the development of a new technique for automatic monitoring of armor layers of flexible risers. The proposed approach aims to minimize these current uncertainties by combining electromagnetic measurements with optical strain gage data through a recursive least squares (RLSs adaptive filter.

  17. Dynamic testing of POSI-SEAL motor-operated butterfly valves using strain gages

    International Nuclear Information System (INIS)

    Richard, M.C.; Chiou, D.


    Utilities operating nuclear power plants recognize that the correct functioning of all motor-operated valves, and particularly those in safety-related systems, is of paramount importance. The U.S. Nuclear Regulatory Commission has issued Generic Letter 89-10 relative to this concern. Operability must be demonstrated under design-basis conditions. In order to demonstrate operability of motor-operated butterfly valves, the valve stem torque must be determined. The valve stem torque is a function of seat material, stem packing, stem bearing friction, and hydrodynamic lift and drag. The total valve operating hydrodynamic torque can be predicted using the valve manufacturer's data and the differential pressure. In order to validate the valve manufacturer's data, the actual total valve hydrodynamic torque is measured using strain gages mounted directly on the valve stem. This paper presents the results of comparing the predicted total valve operating hydrodynamic torque with the actual total valve operating hydrodynamic torque for six POSI-SEAL Class 150 high performance butterfly valves

  18. An introduction to NH-A neutron earth base moisture gage

    International Nuclear Information System (INIS)

    Zhu Huaian; Jiang Yulan; Yin Xilin; Yu Peiying; Luo Pinjie


    NH-A neutron earth base moisture gage is an accurate instrument which can measure earth moisture rapidly and non-destructively and display moisture results immediately. The deviation is estimated at ±0.012g/cm

  19. Analysis of residual transverse stresses in a thick UD glass/polyester pultruded profile using hole drilling with strain gage and digital image correlation (United States)

    Yuksel, Onur; Baran, Ismet; Ersoy, Nuri; Akkerman, Remko


    Process induced stresses inherently exist in fiber reinforced polymer composites particularly in thick parts due to the presence of non-uniform cure, shrinkage and thermal expansion/contraction during manufacturing. In order to increase the reliability and the performance of the composite materials, process models are developed to predict the residual stress formation. The accuracy of the process models is dependent on the geometrical (micro to macro), material and process parameters as well as the numerical implementation. Therefore, in order to have reliable process modelling framework, there is a need for validation and if necessary calibration of the developed models. This study focuses on measurement of the transverse residual stresses in a relatively thick pultruded profile (20×20 mm) made of glass/polyester. Process-induced residual stresses in the middle of the profile are examined with different techniques which have never been applied for transverse residual stresses in thick unidirectional composites. Hole drilling method with strain gage and digital image correlation are employed. Strain values measured from measurements are used in a finite element model (FEM) to simulate the hole drilling process and predict the residual stress level. The measured released strain is found to be approximately 180 μm/m from the strain gage. The tensile residual stress at the core of the profile is estimated approximately as 7-10 MPa. Proposed methods and measured values in this study will enable validation and calibration of the process models based on the residual stresses.

  20. Strain Gage Load Calibration of the Wing Interface Fittings for the Adaptive Compliant Trailing Edge Flap Flight Test (United States)

    Miller, Eric J.; Holguin, Andrew C.; Cruz, Josue; Lokos, William A.


    This is the presentation to follow conference paper of the same name. The adaptive compliant trailing edge (ACTE) flap experiment safety of flight requires that the flap to wing interface loads be sensed and monitored in real time to ensure that the wing structural load limits are not exceeded. This paper discusses the strain gage load calibration testing and load equation derivation methodology for the ACTE interface fittings. Both the left and right wing flap interfaces will be monitored and each contains four uniquely designed and instrumented flap interface fittings. The interface hardware design and instrumentation layout are discussed. Twenty one applied test load cases were developed using the predicted in-flight loads for the ACTE experiment.

  1. Standard test methods for performance characteristics of metallic bonded resistance strain gages

    CERN Document Server

    American Society for Testing and Materials. Philadelphia


    1.1 The purpose of this standard is to provide uniform test methods for the determination of strain gauge performance characteristics. Suggested testing equipment designs are included. 1.2 Test Methods E 251 describes methods and procedures for determining five strain gauge parameters: Section Part I—General Requirements 7 Part II—Resistance at a Reference Temperature 8 Part III—Gauge Factor at a Reference Temperature 9 Part IV—Temperature Coefficient of Gauge Factor\t10 Part V—Transverse Sensitivity\t11 Part VI—Thermal Output\t12 1.3 Strain gauges are very sensitive devices with essentially infinite resolution. Their response to strain, however, is low and great care must be exercised in their use. The performance characteristics identified by these test methods must be known to an acceptable accuracy to obtain meaningful results in field applications. 1.3.1 Strain gauge resistance is used to balance instrumentation circuits and to provide a reference value for measurements since all data are...

  2. Inexpensive Bolt-Load Gage (United States)

    Long, M. J.


    "Built-in" gage determines whether large bolt or stud has been torqued to desired load and provides for continuous inspection to ensure proper load is being maintained. Gage detects longitudinal stress/strain bolt; requires no electronic or sonic test equipment.

  3. Design and construction of a strain gage compression load cell to measure rolling forces

    International Nuclear Information System (INIS)

    Schoeffer, L.; Borchardt, I.G.; Carvalho, L.F.A.


    A complete detailed mechanical desion of a strain gauge compression load cell is presented. This cell was specialy designed to measure rolling forces at conventional duo or trio industrial roughing stands. The stands, in general, have little space (height) to adjust to the cells. Moreover the contact stands surfaces are very rough. Do to this facts, load cells of elastic cilindrical geometries are not recommended for accuracies better than 8%. This work describes the complete design and the construction of a circular (membrane) steel plate load cell. A prototype of 300 KN (approximately 30t) capacity, with 2% accuracies and with a height of 6 cm was constructed and tested. The design proposed is a general one and permits the construction of small load cells to measure any compression load [pt

  4. Streamflow Gaging Stations (United States)

    Department of Homeland Security — This map layer shows selected streamflow gaging stations of the United States, Puerto Rico, and the U.S. Virgin Islands, in 2013. Gaging stations, or gages, measure...

  5. Versatile radiation gaging system

    International Nuclear Information System (INIS)

    Long, P.J.


    The attributes of computerized versatile radiation gaging systems are described. The gages are used to measure plating thicknesses and material characteristics that can be determined from radiation attenuation and/or x-ray fluorescence measurements

  6. GAGES-II: Geospatial Attributes of Gages for Evaluating Streamflow (United States)

    Falcone, James A.


    This dataset, termed "GAGES II", an acronym for Geospatial Attributes of Gages for Evaluating Streamflow, version II, provides geospatial data and classifications for 9,322 stream gages maintained by the U.S. Geological Survey (USGS). It is an update to the original GAGES, which was published as a Data Paper on the journal Ecology's website (Falcone and others, 2010b) in 2010. The GAGES II dataset consists of gages which have had either 20+ complete years (not necessarily continuous) of discharge record since 1950, or are currently active, as of water year 2009, and whose watersheds lie within the United States, including Alaska, Hawaii, and Puerto Rico. Reference gages were identified based on indicators that they were the least-disturbed watersheds within the framework of broad regions, based on 12 major ecoregions across the United States. Of the 9,322 total sites, 2,057 are classified as reference, and 7,265 as non-reference. Of the 2,057 reference sites, 1,633 have (through 2009) 20+ years of record since 1950. Some sites have very long flow records: a number of gages have been in continuous service since 1900 (at least), and have 110 years of complete record (1900-2009) to date. The geospatial data include several hundred watershed characteristics compiled from national data sources, including environmental features (e.g. climate – including historical precipitation, geology, soils, topography) and anthropogenic influences (e.g. land use, road density, presence of dams, canals, or power plants). The dataset also includes comments from local USGS Water Science Centers, based on Annual Data Reports, pertinent to hydrologic modifications and influences. The data posted also include watershed boundaries in GIS format. This overall dataset is different in nature to the USGS Hydro-Climatic Data Network (HCDN; Slack and Landwehr 1992), whose data evaluation ended with water year 1988. The HCDN identifies stream gages which at some point in their history had

  7. Streamflow characteristics based on data through water year 2009 for selected streamflow-gaging stations in or near Montana: Chapter E in Montana StreamStats (United States)

    McCarthy, Peter M.


    Chapter E of this Scientific Investigations Report documents results from a study by the U.S. Geological Survey, in cooperation with the Montana Department of Environmental Quality and the Montana Department of Natural Resources and Conservation, to provide an update of statewide streamflow characteristics based on data through water year 2009 for streamflow-gaging stations in or near Montana. Streamflow characteristics are presented for 408 streamflow-gaging stations in Montana and adjacent areas having 10 or more years of record. Data include the magnitude and probability of annual low and high streamflow, the magnitude and probability of low streamflow for three seasons (March–June, July–October, and November–February), streamflow duration statistics for monthly and annual periods, and mean streamflows for monthly and annual periods. Streamflow is considered to be regulated at streamflow-gaging stations where dams or other large-scale human modifications affect 20 percent or more of the contributing drainage basin. Separate streamflow characteristics are presented for the unregulated and regulated periods of record for streamflow-gaging stations with sufficient data.

  8. Processing and Characterization of a Novel Distributed Strain Sensor Using Carbon Nanotube-Based Nonwoven Composites

    Directory of Open Access Journals (Sweden)

    Hongbo Dai


    Full Text Available This paper describes the development of an innovative carbon nanotube-based non-woven composite sensor that can be tailored for strain sensing properties and potentially offers a reliable and cost-effective sensing option for structural health monitoring (SHM. This novel strain sensor is fabricated using a readily scalable process of coating Carbon nanotubes (CNT onto a nonwoven carrier fabric to form an electrically-isotropic conductive network. Epoxy is then infused into the CNT-modified fabric to form a free-standing nanocomposite strain sensor. By measuring the changes in the electrical properties of the sensing composite the deformation can be measured in real-time. The sensors are repeatable and linear up to 0.4% strain. Highest elastic strain gage factors of 1.9 and 4.0 have been achieved in the longitudinal and transverse direction, respectively. Although the longitudinal gage factor of the newly formed nanocomposite sensor is close to some metallic foil strain gages, the proposed sensing methodology offers spatial coverage, manufacturing customizability, distributed sensing capability as well as transverse sensitivity.

  9. Strain measurement based battery testing (United States)

    Xu, Jeff Qiang; Steiber, Joe; Wall, Craig M.; Smith, Robert; Ng, Cheuk


    A method and system for strain-based estimation of the state of health of a battery, from an initial state to an aged state, is provided. A strain gauge is applied to the battery. A first strain measurement is performed on the battery, using the strain gauge, at a selected charge capacity of the battery and at the initial state of the battery. A second strain measurement is performed on the battery, using the strain gauge, at the selected charge capacity of the battery and at the aged state of the battery. The capacity degradation of the battery is estimated as the difference between the first and second strain measurements divided by the first strain measurement.

  10. Improved nuclear gage development - phase i and ii. Interim report

    International Nuclear Information System (INIS)

    Chan, E.L.; Champion, F.C.; Castanon, D.R.; Chang, J.C.; Hannon, J.B.


    This report contains Phase I and II of an investigation covering the design and construction of a prototype nuclear-moisture-density backscatter gage. Gage development was based upon the analysis of several factors which affect gage performance. This research indicated that the prototype gage measurements are approximately equivalent to measurements obtained by a commercial transmission gage. The implication of this research finding concerns the qualification of the backscatter test method as a valid, reliable, and expedient procedure for determining in-situ soil conditions

  11. SAF line pellet gaging

    International Nuclear Information System (INIS)

    Jedlovec, D.R.; Bowen, W.W.; Brown, R.L.


    Automated and remotely controlled pellet inspection operations will be utilized in the Secure Automated Fabrication (SAF) line. A prototypic pellet gage was designed and tested to verify conformance to the functions and requirements for measurement of diameter, surface flaws and weight-per-unit length

  12. Film-based Sensors with Piezoresistive Molecular Conductors as Active Components Strain Damage and Thermal Regeneration

    Directory of Open Access Journals (Sweden)

    Elena Laukhina


    Full Text Available The article is addressed to the development of flexible all-organic bi layer (BL film-based sensors being capable of measuring strain as a well-defined electrical signal in a wide range of elongations and temperature. The purpose was achieved by covering polycarbonate films with the polycrystalline layer of a high piezoresistive organic molecular conductor. To determine restrictions for sensor applications, the effect of monoaxial strain on the resistance and texture of the sensing layers of BL films was studied. The experiments have shown that the maximum strain before fracture is about 1 %. A thermal regeneration of the sensing layer of the BL film-based sensors that were damaged by cyclic load is also described. These sensors are able to take the place of conventional metal-based strain and pressure gages in low cost innovative controlling and monitoring technologies.

  13. Towards the determination of deformation rates - pinch-and-swell structures as a natural and simulated paleo-strain rate gage (United States)

    Peters, Max; Poulet, Thomas; Karrech, Ali; Regenauer-Lieb, Klaus; Herwegh, Marco


    Layered rocks deformed under viscous deformation conditions frequently show boudinage, a phenomenon that results from differences in effective viscosity between the involved layers. In the case of continuous necking of a mechanically stiffer layer embedded in a weaker matrix, symmetric boudins are interpreted as the result of dominant visco-plastic deformation (Goscombe et al., 2004). However, information on the physical conditions, material properties and deformation processes are yet unknown. Natural samples deformed under low-grade (TAustin and Evans (2007) combined with the thermodynamic approach of Regenauer-Lieb and Yuen (2004). Depending on the dissipated energy, grain sizes in these domains vary substantially in space and time. While low strain rates (low stresses) in the swells favor grain growth and GSI dominated deformation, high strain rates in the pinches provoke dramatic grain size reduction with an increasing contribution of GSS as a function of decreasing grain size. The development of symmetric necks observed in nature thus seems to coincide with the transition from dislocation to diffusion creep dominated flow with continuous grain size reduction and growth from swell to neck at relatively high extensional strains. REFERENCES Austin, N. and Evans, B. (2007). Paleowattmeters: A scaling relation for dynamically recrystallized grain size. Geology, 35. Goscombe, B.D., Passchier, C.W. and Hand, M. (2004). Boudinage classification: End-member boudin types and modified boudin structures, Journal of Structural Geology, 26. Herwegh, M., Poulet, T., Karrech, A. and Regenauer-Lieb, K. (in press). From transient to steady state deformation and grain size: A thermodynamic approach using elasto-visco-plastic numerical modeling. Journal of Geophysical Research. Karrech, A., Regenauer-Lieb, K. and Poulet, T. (2011a). A Damaged visco-plasticity model for pressure and temperature sensitive geomaterials. Journal of Engineering Science 49. Regenauer-Lieb, K. and Yuen

  14. Low pressure gage type VM-01

    International Nuclear Information System (INIS)

    Brandea, I.; Curuia, M.; Culcer, M.


    High vacuum systems became an important element of many applied technologies, from gas analysers to rocket engines. An intelligent apparatus for pressure measurement in the range of 10 -3 - 10 -8 mbar, with incorporated INTEL 80C51 microcontroller is presented. Based on a Bayard-Alpert hot cathode gage, equally developed in our institute, the pressure gage allows the displaying of different operation parameters and also of the error codes for different kinds of malfunctioning, as for instance missing of grid voltage, grid-collector breakdown, pressure increasing above 10 -3 mbar. Its operation is based on a microcontroller assembly language program especially worked out and introduced in the central units EPROM memory. The gage characteristics for different gases are also introduced in an EPROM memory, and the type of the gas is selected by the operator from the front panel. One can select also from the front panel the pressure unit (mbar, torr, Pa). If a remote control is necessary, this can be done by means of a PC, with a program written in the LabVIEW graphical programming language. The pressure gage was tested and calibrated in relation with an EDWARDS vacuum measuring system and provided a good accuracy (better than 25%). Its field of application is both laboratory and industrial measurements. Its main features are: - supply voltage, 220 V ac / 50 Hz; - power consumption, 30 W; - gage's grid supply voltage, 160 V; grid current, 2 mA / p = 10 -5 ...10 -8 mbar and 0.2 mA / p = 10 -3 ...10 -5 mbar; - cathode heating current, max. 3 A; - measuring range, 10 -3 ...10 -8 mbar; - error of measurement, ±35%; - remote control, according to the RS232 standard; - size, 320 x 200 x 100 mm; - weight, 3.5 Kg. (authors)

  15. GAGES: A stream gage database for evaluating natural and alteredflow conditions in the conterminous United States (United States)

    Falcone, James A.; Carlisle, Daren M.; Wolock, David M.; Meador, Michael R.


    Stream flow is a controlling element in the ecology of rivers and streams. Knowledge of the natural flow regime facilitates the assessment of whether specific hydrologic attributes have been altered by humans in a particular stream and the establishment of specific goals for stream-flow restoration. Because most streams are ungaged or have been altered by human influences, characterizing the natural flow regime is often only possible by estimating flow characteristics based on nearby stream gages of reference quality, i.e., gaged locations that are least disturbed by human influences. The ability to evaluate natural stream flow, that which is not altered by human activities, would be enhanced by the existence of a nationally consistent and up-to-date database of gages in relatively undisturbed watersheds.

  16. Discharge measurements at gaging stations (United States)

    Turnipseed, D. Phil; Sauer, Vernon B.


    The techniques and standards for making discharge measurements at streamflow gaging stations are described in this publication. The vertical axis rotating-element current meter, principally the Price current meter, has been traditionally used for most measurements of discharge; however, advancements in acoustic technology have led to important developments in the use of acoustic Doppler current profilers, acoustic Doppler velocimeters, and other emerging technologies for the measurement of discharge. These new instruments, based on acoustic Doppler theory, have the advantage of no moving parts, and in the case of the acoustic Doppler current profiler, quickly and easily provide three-dimensional stream-velocity profile data through much of the vertical water column. For much of the discussion of acoustic Doppler current profiler moving-boat methodology, the reader is referred to U.S. Geological Survey Techniques and Methods 3-A22 (Mueller and Wagner, 2009). Personal digital assistants (PDAs), electronic field notebooks, and other personal computers provide fast and efficient data-collection methods that are more error-free than traditional hand methods. The use of portable weirs and flumes, floats, volumetric tanks, indirect methods, and tracers in measuring discharge are briefly described.

  17. Stage measurement at gaging stations (United States)

    Sauer, Vernon B.; Turnipseed, D. Phil


    Stream and reservoir stage are critical parameters in the computation of stream discharge and reservoir volume, respectively. In addition, a record of stream stage is useful in the design of structures that may be affected by stream elevation, as well as for the planning for various uses of flood plains. This report describes equipment and methodology for the observation, sensing, and recording of stage in streams and reservoirs. Although the U.S. Geological Survey (USGS) still uses the traditional, basic stilling-well float system as a predominant gaging station, modern electronic stage sensors and water-level recorders are now commonly used. Bubble gages coupled with nonsubmersible pressure transducers eliminate the need for stilling wells. Submersible pressure transducers have become common in use for the measurement of stage in both rivers and lakes. Furthermore, noncontact methods, such as radar, acoustic, and laser methods of sensing water levels, are being developed and tested, and in the case of radar, are commonly used for the measurement of stage. This report describes commonly used gaging-station structures, as well as the design and operation of gaging stations. Almost all of the equipment and instruments described in this report will meet the accuracy standard set by the USGS Office of Surface Water (OSW) for the measurement of stage for most applications, which is ±0.01 foot (ft) or 0.2 percent of the effective stage. Several telemetry systems are used to transmit stage data from the gaging station to the office, although satellite telemetry has become the standard. These telemetry systems provide near real-time stage data, as well as other information that alerts the hydrographer to extreme or abnormal events, and instrument malfunctions.

  18. Magnitude, frequency, and trends of floods at gaged and ungaged sites in Washington, based on data through water year 2014 (United States)

    Mastin, Mark C.; Konrad, Christopher P.; Veilleux, Andrea G.; Tecca, Alison E.


    of the time equivalent to peak flows for peaks with a 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence intervals, respectively. Annual precipitation and drainage area were the significant basin characteristics in the regression equations for all four regression regions in Washington and forest cover was significant for the two regression regions in eastern Washington. Average standard error of prediction for the regional regression equations ranged from 70.19 to 125.72 percent for Regression Regions 1 and 2 on the eastern side of the Cascade Mountains and from 43.22 to 58.04 percent for Regression Regions 3 and 4 on the western side of the Cascade Mountains. The pseudo coefficient of determination (where a value of 100 signifies a perfect regression model) ranged from 68.39 to 90.68 for Regression Regions 1 and 2, and 92.35 to 95.44 for Regions 3 and 4.The calculated AEP statistics for the streamgages and the regional regression equations are expected to be incorporated into StreamStats after the publication of this report. StreamStats is the interactive Web-based map tool created by the U.S. Geological Survey to allow the user to choose a streamgage and obtain published statistics or choose ungaged locations where the program automatically applies the regional regression equations and computes the estimates of the AEP statistics.

  19. Peak-flow frequency analyses and results based on data through water year 2011 for selected streamflow-gaging stations in or near Montana: Chapter C in Montana StreamStats (United States)

    Sando, Steven K.; McCarthy, Peter M.; Dutton, DeAnn M.


    Chapter C of this Scientific Investigations Report documents results from a study by the U.S. Geological Survey, in cooperation with the Montana Department of Transportation and the Montana Department of Natural Resources, to provide an update of statewide peak-flow frequency analyses and results for Montana. The purpose of this report chapter is to present peak-flow frequency analyses and results for 725 streamflow-gaging stations in or near Montana based on data through water year 2011. The 725 streamflow-gaging stations included in this study represent nearly all streamflowgaging stations in Montana (plus some from adjacent states or Canadian Provinces) that have at least 10 years of peak-flow records through water year 2011. For 29 of the 725 streamflow-gaging stations, peak-flow frequency analyses and results are reported for both unregulated and regulated conditions. Thus, peak-flow frequency analyses and results are reported for a total of 754 analyses. Estimates of peak-flow magnitudes for 66.7-, 50-, 42.9-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities are reported. These annual exceedance probabilities correspond to 1.5-, 2-, 2.33-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence intervals.

  20. Measurement of aerosol concentration with a beta-ray gage

    International Nuclear Information System (INIS)

    Auzac, G. d'; Dubillot, J.


    Because dusts in suspension are a dangerous polluting agent, several methods have been used to monitor their concentration. Among these, the beta-ray gage enjoys a privileged position. The authors describe such a gage and discuss the conditions to be observed for it to be capable of giving results comparable to those obtained with manual gravimetric methods. The satisfactory results obtained led to standardization of the method and a whole range of instruments based on this principle are employed in pollution supervising networks and for continuously monitoring industrial emissions [fr

  1. Gage for measuring coastal erosion and sedimentation (United States)

    Carpini, T. D.; Moughon, W. C.


    Underwater sand height gage, which measures heights up to 12 inches, is comprised of two standard flush-diaphragm pressure transducers. Gage is very sensitive to buried water heights and is useful as a research tool in study of wet earth and landslide phenomena.

  2. Non-metallic gage for gap

    International Nuclear Information System (INIS)

    Hiroki, Hideo.


    The present invention concerns a non-metallic gage for detecting a gap which can not be seen from the out side such as a gap between a water pipe and fuel rods without damaging an objective material as to whether the gap is formed within a standard value or not. The gage is made of a synthetic resin, for example, polyacetal having such a hardness as not damaging the objective material and endurable to repeating flexure upon use. The gage comprises a short gage portion having a predetermined standard thickness and an flexible extended connection portion reduced in the thickness. Provision of the extended connection portion enables wide range flexure thereof such as ±60deg relative to insertion direction during insertion operation upon testing to solve a drawback in the prior art such as worry of breakage of the gage, thereby enabling to conduct inspection rapidly at high reliability. (N.H.)

  3. Ball mounting fixture for a roundness gage (United States)

    Gauler, Allen L.; Pasieka, Donald F.


    A ball mounting fixture for a roundness gage is disclosed. The fixture includes a pair of chuck assemblies oriented substantially transversely with respect to one another and mounted on a common base. Each chuck assembly preferably includes a rotary stage and a wobble plate affixed thereto. A ball chuck affixed to each wobble plate is operable to selectively support a ball to be measured for roundness, with the wobble plate permitting the ball chuck to be tilted to center the ball on the axis of rotation of the rotary stage. In a preferred embodiment, each chuck assembly includes a vacuum chuck operable to selectively support the ball to be measured for roundness. The mounting fixture enables a series of roundness measurements to be taken with a conventional rotating gagehead roundness instrument, which measurements can be utilized to determine the sphericity of the ball.

  4. The effects of incomplete annealing on the temperature dependence of sheet resistance and gage factor in aluminum and phosphorus implanted silicon on sapphire (United States)

    Pisciotta, B. P.; Gross, C.


    Partial annealing of damage to the crystal lattice during ion implantation reduces the temperature coefficient of resistivity of ion-implanted silicon, while facilitating controlled doping. Reliance on this method for temperature compensation of the resistivity and strain-gage factor is discussed. Implantation conditions and annealing conditions are detailed. The gage factor and its temperature variation are not drastically affected by crystal damage for some crystal orientations. A model is proposed to account for the effects of electron damage on the temperature dependence of resistivity and on silicon piezoresistance. The results are applicable to the design of silicon-on-sapphire strain gages with high gage factors.

  5. Strain-based fracture assessment of pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Olsoe, Erlend; Oestby, Erling; Nyhus, Baard [SINTEF, Trondheim (Norway); Skallerud, Bjoern; Holthe, Kjell [Norwegian University of Science and Technology (NTNU), Trondheim (Norway); Berg, Espen [LINKftr AS, Trondheim (Norway)


    The oil and gas industry moves into harsher regions and faces challenges with i.e. deep water, arctic conditions and seismic regions. Consequently, ensuring the integrity of pipelines becomes more challenging, and potential large deformation scenarios that can be attributed to the above mentioned areas have lead to a current strong focus on strain-based fracture assessment methods for pipelines. However, no widely established methods exist today. In this paper specific challenges related to development of such methods are discussed. Keywords are biaxial loading, crack driving force relations, ductile tearing resistance, and definition of strain capacity. The effect of the different features will be illustrated with both experimental and numerical simulation results. Experimental results presented will cover both large- and small-scale testing. A highly efficient and accurate line-spring based numerical fracture assessment method will be presented. A simplified scheme for a strain-based fracture assessment method will also be briefly outlined, and the extension of this method to also include partial safety factors is discussed. (author)

  6. Testing for moisture content in foods by neutron gaging

    International Nuclear Information System (INIS)

    Helf, S.


    Neutron gaging was applied to the testing for moisture content in bulk powdered foods and in canned Army field rations. The technique is based on the moderation or thermalization of fast neutrons by hydrogenous matter and the measurement of thermal neutron intensity as a function of moisture content. A small californium-252 capsule, of approximate output 10 7 neutrons per second, was used as the source of fast neutrons. It is concluded that a fast neutron moderation technique is feasible for the nondestructive measurement or control of moisture or both in near-dry bulk powdered foods. Samples must be measured under identical geometric conditions, that is, uniform bulk density and volume using a standard metal container or cell. For canned or otherwise prepacked rations, measurement of moisture is interfered with by variations in fill weight among cans or packages of the same product. A gamma-ray attenuation gaging method proved to be of insufficient sensitivity to correct for fill weight variation and was further complicated by nonuniformity in can wall dimensions. Neutron gaging, however, appears to be quite useful for monitoring a standard packaged item for fill weight since the neutron signal is virtually unaffected by variations in container dimensions. The radiation dose imparted to a sample or package of food subjected to such a test is judged to pose no threat to humans from subsequent consumption of the food. An estimate is given for the cost range of a commercial neutron gage and of encapsulated radioisotopic neutron sources

  7. Ultrasensitive, Stretchable Strain Sensors Based on Fragmented Carbon Nanotube Papers

    KAUST Repository

    Zhou, Jian; Yu, Hu; Xu, Xuezhu; Han, Fei; Lubineau, Gilles


    The development of strain sensors featuring both ultra high sensitivity and high stretchability is still a challenge. We demonstrate that strain sensors based on fragmented single-walled carbon nanotube (SWCNT) paper embedded in poly

  8. Latin square three dimensional gage master (United States)

    Jones, Lynn L.


    A gage master for coordinate measuring machines has an nxn array of objects distributed in the Z coordinate utilizing the concept of a Latin square experimental design. Using analysis of variance techniques, the invention may be used to identify sources of error in machine geometry and quantify machine accuracy.

  9. Sensitivity Enhancement of FBG-Based Strain Sensor. (United States)

    Li, Ruiya; Chen, Yiyang; Tan, Yuegang; Zhou, Zude; Li, Tianliang; Mao, Jian


    A novel fiber Bragg grating (FBG)-based strain sensor with a high-sensitivity is presented in this paper. The proposed FBG-based strain sensor enhances sensitivity by pasting the FBG on a substrate with a lever structure. This typical mechanical configuration mechanically amplifies the strain of the FBG to enhance overall sensitivity. As this mechanical configuration has a high stiffness, the proposed sensor can achieve a high resonant frequency and a wide dynamic working range. The sensing principle is presented, and the corresponding theoretical model is derived and validated. Experimental results demonstrate that the developed FBG-based strain sensor achieves an enhanced strain sensitivity of 6.2 pm/με, which is consistent with the theoretical analysis result. The strain sensitivity of the developed sensor is 5.2 times of the strain sensitivity of a bare fiber Bragg grating strain sensor. The dynamic characteristics of this sensor are investigated through the finite element method (FEM) and experimental tests. The developed sensor exhibits an excellent strain-sensitivity-enhancing property in a wide frequency range. The proposed high-sensitivity FBG-based strain sensor can be used for small-amplitude micro-strain measurement in harsh industrial environments.

  10. Long term strain behavior of PMMA based polymer optical fibers

    DEFF Research Database (Denmark)

    Bundalo, Ivan-Lazar; Nielsen, Kristian; Woyessa, Getinet


    We are reporting on the viscoelasticity of PMMA based Fiber Bragg Grating (FBG) strain sensors when exposed to repeated sequences of long term strain and relaxation with various duty-cycles. In terms of the FBG wavelength and how it follows the strain cycle, we have shown that in the small strain...... regime (up to 1%) an elastic-dominated fast relaxing range, which is followed by a mainly viscous relaxation, depends both on the strain level and on the strain duration. For a small ratio of the strain-relax durations, this fast relaxation range stays almost the same. However, with increasing strain...... duration, for the same relaxation time, this range will be shortened, which might influence the sensing capabilities of the fiber sensor....

  11. An ultrasensitive strain sensor with a wide strain range based on graphene armour scales. (United States)

    Yang, Yi-Fan; Tao, Lu-Qi; Pang, Yu; Tian, He; Ju, Zhen-Yi; Wu, Xiao-Ming; Yang, Yi; Ren, Tian-Ling


    An ultrasensitive strain sensor with a wide strain range based on graphene armour scales is demonstrated in this paper. The sensor shows an ultra-high gauge factor (GF, up to 1054) and a wide strain range (ε = 26%), both of which present an advantage compared to most other flexible sensors. Moreover, the sensor is developed by a simple fabrication process. Due to the excellent performance, this strain sensor can meet the demands of subtle, large and complex human motion monitoring, which indicates its tremendous application potential in health monitoring, mechanical control, real-time motion monitoring and so on.

  12. Mechanism of Strain Rate Effect Based on Dislocation Theory

    International Nuclear Information System (INIS)

    Kun, Qin; Shi-Sheng, Hu; Li-Ming, Yang


    Based on dislocation theory, we investigate the mechanism of strain rate effect. Strain rate effect and dislocation motion are bridged by Orowan's relationship, and the stress dependence of dislocation velocity is considered as the dynamics relationship of dislocation motion. The mechanism of strain rate effect is then investigated qualitatively by using these two relationships although the kinematics relationship of dislocation motion is absent due to complicated styles of dislocation motion. The process of strain rate effect is interpreted and some details of strain rate effect are adequately discussed. The present analyses agree with the existing experimental results. Based on the analyses, we propose that strain rate criteria rather than stress criteria should be satisfied when a metal is fully yielded at a given strain rate. (condensed matter: structure, mechanical and thermal properties)

  13. A self-strain feedback tuning-fork-shaped ionic polymer metal composite clamping actuator with soft matter elasticity-detecting capability for biomedical applications. (United States)

    Feng, Guo-Hua; Huang, Wei-Lun


    This paper presents a smart tuning-fork-shaped ionic polymer metal composite (IPMC) clamping actuator for biomedical applications. The two fingers of the actuator, which perform the clamping motion, can be electrically controlled through a unique electrode design on the IPMC material. The generated displacement or strain of the fingers can be sensed using an integrated soft strain-gage sensor. The IPMC actuator and associated soft strain gage were fabricated using a micromachining technique. A 13.5×4×2 mm(3) actuator was shaped from Nafion solution and a selectively grown metal electrode formed the active region. The strain gage consisted of patterned copper foil and polyethylene as a substrate. The relationship between the strain gage voltage output and the displacement at the front end of the actuator's fingers was characterized. The equivalent Young's modulus, 13.65 MPa, of the soft-strain-gage-integrated IPMC finger was analyzed. The produced clamping force exhibited a linear increasing rate of 1.07 mN/s, based on a dc driving voltage of 7 V. Using the developed actuator to clamp soft matter and simultaneously acquire its Young's modulus was achieved. This demonstrated the feasibility of the palpation function and the potential use of the actuator in minimally invasive surgery. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. GAGE cancer-germline antigens are recruited to the nuclear envelope by germ cell-less (GCL)

    DEFF Research Database (Denmark)

    Gjerstorff, Morten F; Rösner, Heike I; Pedersen, Christina B


    GAGE proteins are highly similar, primate-specific molecules with unique primary structure and undefined cellular roles. They are restricted to cells of the germ line in adult healthy individuals, but are broadly expressed in a wide range of cancers. In a yeast two-hybrid screen we identified the...... different dsDNA fragments, suggesting sequence-nonspecific binding. Dual association of GAGE family members with GCL at the nuclear envelope inner membrane in cells, and with dsDNA in vitro, implicate GAGE proteins in chromatin regulation in germ cells and cancer cells....... the metazoan transcriptional regulator, Germ cell-less (GCL), as an interaction partner of GAGE12I. GCL directly binds LEM-domain proteins (LAP2β, emerin, MAN1) at the nuclear envelope, and we found that GAGE proteins were recruited to the nuclear envelope inner membrane by GCL. Based on yeast two...

  15. The shape of a strain-based failure assessment diagram

    International Nuclear Information System (INIS)

    Budden, P.J.; Ainsworth, R.A.


    There have been a number of recent developments of strain-based fracture assessment approaches, including proposals by Budden [Engng Frac Mech 2006;73:537–52] for a strain-based failure assessment diagram (FAD) related to the conventional stress-based FAD. However, recent comparisons with finite element (FE) data have shown that this proposed strain-based FAD can be non-conservative in some cases, particularly for deeper cracks and materials with little strain-hardening capacity. Therefore, this paper re-examines the shape of the strain-based FAD, guided by these FE analyses and some theoretical analysis. On this basis, modified proposals for the shape of the strain-based FAD are given, including simplified and more detailed options in line with the options available for stress-based FADs in existing fitness-for-service procedures. The proposals are then illustrated by a worked example and by comparison with FE data, which demonstrate that the new proposals are generally conservative. - Highlights: ► The strain-based failure assessment diagram approach to fracture is developed. ► The new approach modifies earlier proposals by Budden. ► A new generic Option 1 strain-based failure assessment diagram is proposed. ► Validation based on finite element J data for plates and cylinders is presented. ► The new approach is generally conservative compared with the finite element data.

  16. Monitoring of prestressed concrete pressure vessels. 1. An overview of concrete embedment strain instrumentation and calibration test results for selected concrete embedment strain meters

    International Nuclear Information System (INIS)

    Naus, D.J.; Hurtt, C.C.


    The report presents results of calibration tests on strain meters. The approach was divided into two phases: (1) an overview of meter performance criteria for PCPV applications and techniques for strain measurements in concrete and (2) procurement of commercially available gages and their evaluation to assess the reliability of manufacturer-supplied calibration factors. Calibration test results for gages embedded in 15.2-cm-diam by 54-cm cylindrical concrete specimens indicated that calibration factors should be determined (verified) by embedding samples of the gages in test specimens fabricated using a representative mix and that further research should be conducted on other measurement techniques based on inductance, capacitance, semiconductors, and fluidic principles

  17. Sensitivity of hot-cathode ionization vacuum gages in several gases (United States)

    Holanda, R.


    Four hot-cathode ionization vacuum gages were calibrated in 12 gases. The relative sensitivities of these gages were compared to several gas properties. Ionization cross section was the physical property which correlated best with gage sensitivity. The effects of gage accelerating voltage and ionization-cross-section energy level were analyzed. Recommendations for predicting gage sensitivity according to gage type were made.

  18. Low-temperature strain gauges based on silicon whiskers

    Directory of Open Access Journals (Sweden)

    Druzhinin A. A.


    Full Text Available To create low-temperature strain gauges based on p-type silicon whiskers tensoresistive characteristics of these crystals in 4,2—300 K temperature range were studied. On the basis of p-type Si whiskers with different resistivity the strain gauges for different materials operating at cryogenic temperatures with extremely high gauge factor at 4,2 K were developed, as well as strain gauges operating at liquid helium temperatures in high magnetic fields.

  19. Graphene based strain sensor with LCP substrate (United States)

    Nie, M.; Yang, H. S.; Xia, Y. H.


    A flexible strain sensor constructed by an efficient, low-cost fabrication strategy is presented in this paper. It is assembled by adhering grid-like graphene on LCP substrate. Kinds of measurement setup have been designed to verify that the proposed flexible sensor device is suitable to be used in health monitoring system. From the experiment results, it can be proved that the sensor exhibits the following features: ultra-light, relatively good sensitivity, high reversibility, superior physical robustness, easy fabrication. With the great performance of this flexible strain sensor, it is considered to play an important role in body monitoring, structural health monitoring system, fatigue detection and healthcare systems in the near future.

  20. Design, analysis, and initial testing of a fiber-optic shear gage for three-dimensional, high-temperature flows (United States)

    Orr, Matthew W.

    This investigation concerns the design, analysis, and initial testing of a new, two-component wall shear gage for 3D, high-temperature flows. This gage is a direct-measuring, non-nulling design with a round head surrounded by a small gap. Two flexure wheels are used to allow small motions of the floating head. Fiber-optic displacement sensors measure how far the polished faces of counterweights on the wheels move in relation to a fixed housing as the primary measurement system. No viscous damping was required. The gage has both fiber-optic instrumentation and strain gages mounted on the flexures for validation of the newer fiber optics. The sensor is constructed of Haynes RTM 230RTM, a high-temperature nickel alloy. The gage housing is made of 316 stainless steel. All components of the gage in pure fiber-optic form can survive to a temperature of 1073 K. The bonding methods of the backup strain gages limit their maximum temperature to 473 K. The dynamic range of the gage is from 0--500 Pa (0--10g) and higher shears can be measured by changing the floating head size. Extensive use of finite element modeling was critical to the design and analysis of the gage. Static structural, modal, and thermal analyses were performed on the flexures using the ANSYS finite element package. Static finite element analysis predicted the response of the flexures to a given load, and static calibrations using a direct force method confirmed these results. Finite element modal analysis results were within 16.4% for the first mode and within 30% for the second mode when compared with the experimentally determined modes. Vibration characteristics of the gage were determined from experimental free vibration data after the gage was subjected to an impulse. Uncertainties in the finished geometry make this level of error acceptable. A transient thermal analysis examined the effects of a very high heat flux on the exposed head of the gage. The 100,000 W/m2 heat flux used in this analysis is

  1. Ultrasensitive, Stretchable Strain Sensors Based on Fragmented Carbon Nanotube Papers

    KAUST Repository

    Zhou, Jian


    The development of strain sensors featuring both ultra high sensitivity and high stretchability is still a challenge. We demonstrate that strain sensors based on fragmented single-walled carbon nanotube (SWCNT) paper embedded in poly(dimethylsiloxane) (PDMS) can sustain their sensitivity even at very high strain levels (with a gauge factor of over 10(7) at 50% strain). This record sensitivity is ascribed to the low initial electrical resistance (5-28 Omega) of the SWCNT paper and the wide change in resistance (up to 10(6) Omega) governed by the percolated network of SWCNT in the cracked region. The sensor response remains nearly unchanged after 10 000 strain cycles at 20% proving the robustness of this technology. This fragmentation based sensing system brings opportunities to engineer highly sensitive stretchable sensors.

  2. Estimating flood magnitude and frequency at gaged and ungaged sites on streams in Alaska and conterminous basins in Canada, based on data through water year 2012 (United States)

    Curran, Janet H.; Barth, Nancy A.; Veilleux, Andrea G.; Ourso, Robert T.


    for all estimates. Final station flood frequency estimates for all study streamgages are presented for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities.Regional multiple-regression analysis was used to produce equations for estimating flood frequency statistics from explanatory basin characteristics. Basin characteristics, including physical and climatic variables, were updated for all study streamgages using a geographical information system and geospatial source data. Screening for similar-sized nested basins eliminated hydrologically redundant sites, and screening for eligibility for analysis of explanatory variables eliminated regulated peaks, outburst peaks, and sites with indeterminate basin characteristics. An ordinary least‑squares regression used flood-frequency statistics and basin characteristics for 341 streamgages (284 in Alaska and 57 in Canada) to determine the most suitable combination of basin characteristics for a flood-frequency regression model and to explore regional grouping of streamgages for explaining variability in flood-frequency statistics across the study area. The most suitable model for explaining flood frequency used drainage area and mean annual precipitation as explanatory variables for the entire study area as a region. Final regression equations for estimating the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probability discharge in Alaska and conterminous basins in Canada were developed using a generalized least-squares regression. The average standard error of prediction for the regression equations for the various annual exceedance probabilities ranged from 69 to 82 percent, and the pseudo-coefficient of determination (pseudo-R2) ranged from 85 to 91 percent.The regional regression equations from this study were incorporated into the U.S. Geological Survey StreamStats program for a limited area of the State—the Cook Inlet Basin. StreamStats is a national web-based

  3. An embeddable optical strain gauge based on a buckled beam. (United States)

    Du, Yang; Chen, Yizheng; Zhu, Chen; Zhuang, Yiyang; Huang, Jie


    We report, for the first time, a low cost, compact, and novel mechanically designed extrinsic Fabry-Perot interferometer (EFPI)-based optical fiber sensor with a strain amplification mechanism for strain measurement. The fundamental design principle includes a buckled beam with a coated gold layer, mounted on two grips. A Fabry-Perot cavity is produced between the buckled beam and the endface of a single mode fiber (SMF). A ceramic ferrule is applied for supporting and orienting the SMF. The principal sensor elements are packaged and protected by two designed metal shells. The midpoint of the buckled beam will experience a deflection vertically when the beam is subjected to a horizontally/axially compressive displacement. It has been found that the vertical deflection of the beam at midpoint can be 6-17 times larger than the horizontal/axial displacement, which forms the basis of a strain amplification mechanism. The user-configurable buckling beam geometry-based strain amplification mechanism enables the strain sensor to achieve a wide range of strain measurement sensitivities. The designed EFPI was used to monitor shrinkage of a square brick of mortar. The strain was measured during the drying/curing stage. We envision that it could be a good strain sensor to be embedded in civil materials/structures under a harsh environment for a prolonged period of time.

  4. An embeddable optical strain gauge based on a buckled beam (United States)

    Du, Yang; Chen, Yizheng; Zhu, Chen; Zhuang, Yiyang; Huang, Jie


    We report, for the first time, a low cost, compact, and novel mechanically designed extrinsic Fabry-Perot interferometer (EFPI)-based optical fiber sensor with a strain amplification mechanism for strain measurement. The fundamental design principle includes a buckled beam with a coated gold layer, mounted on two grips. A Fabry-Perot cavity is produced between the buckled beam and the endface of a single mode fiber (SMF). A ceramic ferrule is applied for supporting and orienting the SMF. The principal sensor elements are packaged and protected by two designed metal shells. The midpoint of the buckled beam will experience a deflection vertically when the beam is subjected to a horizontally/axially compressive displacement. It has been found that the vertical deflection of the beam at midpoint can be 6-17 times larger than the horizontal/axial displacement, which forms the basis of a strain amplification mechanism. The user-configurable buckling beam geometry-based strain amplification mechanism enables the strain sensor to achieve a wide range of strain measurement sensitivities. The designed EFPI was used to monitor shrinkage of a square brick of mortar. The strain was measured during the drying/curing stage. We envision that it could be a good strain sensor to be embedded in civil materials/structures under a harsh environment for a prolonged period of time.

  5. Parallel Microcracks-based Ultrasensitive and Highly Stretchable Strain Sensors. (United States)

    Amjadi, Morteza; Turan, Mehmet; Clementson, Cameron P; Sitti, Metin


    There is an increasing demand for flexible, skin-attachable, and wearable strain sensors due to their various potential applications. However, achieving strain sensors with both high sensitivity and high stretchability is still a grand challenge. Here, we propose highly sensitive and stretchable strain sensors based on the reversible microcrack formation in composite thin films. Controllable parallel microcracks are generated in graphite thin films coated on elastomer films. Sensors made of graphite thin films with short microcracks possess high gauge factors (maximum value of 522.6) and stretchability (ε ≥ 50%), whereas sensors with long microcracks show ultrahigh sensitivity (maximum value of 11,344) with limited stretchability (ε ≤ 50%). We demonstrate the high performance strain sensing of our sensors in both small and large strain sensing applications such as human physiological activity recognition, human body large motion capturing, vibration detection, pressure sensing, and soft robotics.

  6. Nanoscale strain engineering of graphene and graphene-based devices

    Institute of Scientific and Technical Information of China (English)

    N-C Yeh; C-C Hsu; M L Teague; J-Q Wang; D A Boyd; C-C Chen


    Structural distortions in nano-materials can induce dramatic changes in their electronic properties. This situation is well manifested in graphene, a two-dimensional honeycomb structure of carbon atoms with only one atomic layer thickness. In particular, strained graphene can result in both charging effects and pseudo-magnetic fields, so that controlled strain on a perfect graphene lattice can be tailored to yield desirable electronic properties. Here, we describe the theoretical foundation for strain-engineering of the electronic properties of graphene, and then provide experimental evidence for strain-induced pseudo-magnetic fields and charging effects in monolayer graphene. We further demonstrate the feasibility of nano-scale strain engineering for graphene-based devices by means of theoretical simula-tions and nano-fabrication technology.


    Energy Technology Data Exchange (ETDEWEB)

    Cook, Jr., H. L.


    Radioactivity gages are available in a variety of configurations to suit the problem of process measurement. The placement of any gage configuration must be selected carefully so that the process material flowing past the gage is representative of actual process conditions. The initial calibration of a gage is relatively simple but when the gage reading is compared with the existing manual sample measurement, confusion can result if the manual measurement is not basically accurate or subject to human error. Routine mechanical and electrical maintenance of the gage is relatively simple, because modern gages use solidstate circuitry with modular plug-in construction. Thus, routine maintenance of the gage is usually limited to restandardization to compensate for source decay. Two types of zero suppression are available, via. fixed and reductionwith-time. If reduction-with-time suppression is used the re-standardization period is about ten times longer than that required for fixed-zero suppression. Routine maintenance of the process piping and machinery is necessary to assure that a representative process material sample continues to flow through the gage. (auth)

  8. A methodology for strain-based fatigue reliability analysis

    International Nuclear Information System (INIS)

    Zhao, Y.X.


    A significant scatter of the cyclic stress-strain (CSS) responses should be noted for a nuclear reactor material, 1Cr18Ni9Ti pipe-weld metal. Existence of the scatter implies that a random cyclic strain applied history will be introduced under any of the loading modes even a deterministic loading history. A non-conservative evaluation might be given in the practice without considering the scatter. A methodology for strain-based fatigue reliability analysis, which has taken into account the scatter, is developed. The responses are approximately modeled by probability-based CSS curves of Ramberg-Osgood relation. The strain-life data are modeled, similarly, by probability-based strain-life curves of Coffin-Manson law. The reliability assessment is constructed by considering interference of the random fatigue strain applied and capacity histories. Probability density functions of the applied and capacity histories are analytically given. The methodology could be conveniently extrapolated to the case of deterministic CSS relation as the existent methods did. Non-conservative evaluation of the deterministic CSS relation and availability of present methodology have been indicated by an analysis of the material test results

  9. Modeling and Calculation of Dent Based on Pipeline Bending Strain

    Directory of Open Access Journals (Sweden)

    Qingshan Feng


    Full Text Available The bending strain of long-distance oil and gas pipelines can be calculated by the in-line inspection tool which used inertial measurement unit (IMU. The bending strain is used to evaluate the strain and displacement of the pipeline. During the bending strain inspection, the dent existing in the pipeline can affect the bending strain data as well. This paper presents a novel method to model and calculate the pipeline dent based on the bending strain. The technique takes inertial mapping data from in-line inspection and calculates depth of dent in the pipeline using Bayesian statistical theory and neural network. To verify accuracy of the proposed method, an in-line inspection tool is used to inspect pipeline to gather data. The calculation of dent shows the method is accurate for the dent, and the mean relative error is 2.44%. The new method provides not only strain of the pipeline dent but also the depth of dent. It is more benefit for integrity management of pipeline for the safety of the pipeline.

  10. Strain-based quench detection for a solenoid superconducting magnet

    International Nuclear Information System (INIS)

    Wang Xingzhe; Guan Mingzhi; Ma Lizhen


    In this paper, we present a non-electric quench detection method based on the strain gauge measurement of a superconducting solenoid magnet at cryogenic temperature under an intense magnetic field. Unlike the traditional voltage measurement of quench detection, the strain-based detection method utilizes low-temperature strain gauges, which evidently reduce electromagnetic noise and breakdown, to measure the magneto/thermo-mechanical behavior of the superconducting magnet during excitation. The magnet excitation, quench tests and trainings were performed on a prototype 5 T superconducting solenoid magnet. The transient strains and their abrupt changes were compared with the current, magnetic field and temperature signals collected during excitation and quench tests to indicate that the strain gauge measurements can detect the quench feature of the superconducting magnet. The proposed method is expected to be able to detect the quench of a superconducting coil independently or utilized together with other electrical methods. In addition, the axial quench propagation velocity of the solenoid is evaluated by the quench time lags among different localized strains. The propagation velocity is enhanced after repeated quench trainings. (paper)

  11. How the Schmidt-Boelter gage really works

    International Nuclear Information System (INIS)

    Kidd, C.T.; Nelson, C.G.


    The Schmidt-Boelter gage is but one version of a proven heat flux measurement concept generally referred to as the axial temperature gradient method. This gage has been used since the mid-1950's and has gained wide acceptance because the transducer provides a high-level, self-generating output signal directly proportional to the heat flux incident upon the sensing surface. Utilization of this transducer in aerospace measurements since the late 1970's has broadened the scope of application of the device, but has raised questions concerning the proper interpretation of the results. The principle of operation of the gage can correctly be divided into two distinct categories-the thermal and thermoelectric functions. The thermal response of the gage can be approximated by simple steady-state equations. But due to the number of different materials required in the construction of the gage, the transient temperature and heat conduction in gage members are more accurately characterized by finite-element thermal analysis techniques. Results of these analyses are presented in graphical format in the paper. Thermoelectric characteristics of the gage are accurately defined by basic principles of thermoelectric thermometry. Altogether, the analyses presented in this paper demonstrate how this transducer actually works. The conclusions presented herein may be different than opinions held by most casual users regarding gage operation. Results of limited laboratory experiments which support the analyses are described and presented

  12. Neutron moisture gaging of agricultural soil

    International Nuclear Information System (INIS)

    Pospisil, S.; Janout, Z.; Kovacik, M.


    The design is described of a neutron moisture gage which consists of a measuring probe, neutron detector, small electronic recording device and a 241 Am-Be radionuclide source. The neutron detector consists of a surface barrier semiconductor silicon detector and a conversion layer of lithium fluoride. The detection of triton which is the reaction product of lithium with neutrons by the silicon detector is manifested as a voltage pulse. The detector has low sensitivity for fast neutrons and for gamma radiation and is suitable for determining moisture values in large volume samples. Verification and calibration measurements were carried out of chernozem, brown soil and podzolic soils in four series. The results are tabulated. Errors of measurement range between 0.8 to 1.0%. The precision of measurement could be improved by the calibration of the device for any type of soil. (E.S.). 4 tabs., 6 refs., 5 figs

  13. Strain-based failure criteria for steel containments

    International Nuclear Information System (INIS)

    Fanous, F.; Greimann, L.F.


    The Containment Integrity Division of the Sandia National Laboratories (Sandia) has been conducting a program to evaluate the performance of containment buildings with internal pressure. Sandia has suggested that in the absence of leakage past penetrations, containment buildings will fail by rupturing after large plastic strains are developed up to ultimate strain of the material. This paper represents a portion of work conducted at Ames Laboratory for Sandia, the objective of which was to identify fabrication details that may affect the performance of a containment building. Construction drawings for nine steel containment buildings were surveyed, and several significant strain concentration regions were identified by using recommendations from Sandia and Section NE-3217 of the ASME Boiler and Pressure Vessel Code. These following regions were identified as: eccentricities in stiffener patterns around penetrations, eccentricities in containment shell middle surface, flat plate covers used on spare penetrations, containment base connection details, and containment heads. Examples of each of these regions were analyzed by the finite-element method, by simplified equations or both. In the case of middle surface eccentricities, the strains were found to be self-limiting. Even though flat plates have primary strains, they are typically designed so as not to control. Bolts in the base connection have primary strains and may control. The circumferential compressive strains introduced at the knuckle during buckling of the containment head grow as the pressure increases, but are somewhat restricted by the meridional tension. Finally, three analysis techniques and their associated failure criteria for the analysis of containment strength are introduced. (orig.)

  14. Experiences with strain based limit state design in The Netherlands

    NARCIS (Netherlands)

    Gresnigt, A.M.; Foeken, R.J. van


    Limit state design differs from conventional design methods in that each failure mode is specifically addressed (e.g. burst, collapse, local buckling, fracture due to insufficient strain capacity of the pipe wall, fatigue). Based on an extensive theoretical and experimental research programme,

  15. Comparison of Ruska and Rosemont pressure gages (U)

    International Nuclear Information System (INIS)

    Harvel, C.D.


    This paper reports that a 150,000 gallon tank was calibrated during the months of May and July of 1990. Six calibration runs were completed. Ruska and Rosemont pressure gages were installed to make in-tank liquid level measurements during the calibration process. A flow meter was used to measure the incremental volumes of water added to or removed from the tank. The Ruska and Rosemont gages were compared to determine the gage best suited for tank operation. One comparison criteria was the tolerance limits of error (LOE) for the predicted standardized in-tank volumes. For accountability purposes, the effects of the two gages on the LOE for the predicted inventory of U-235 were evaluated. The most important comparison criteria was the gage's contribution to the U-235 inventory LOE. The choice of which gage to use depends on the other measurement methods used for material accountability. The contributions to the inventory LOE were evaluated for two in-tank liquid level measurement methods, two concentration measurement methods, and one isotopic measurement method. The results indicate the Ruska pressure gage is best suited for tank operation only if the best concentration measurement method is used

  16. Seismic qualification of piping systems based on strain criteria

    International Nuclear Information System (INIS)

    Peters, K.; Rangette, A.


    Typical LMFBR piping is characterized by elevated temperature and low pressure levels. Taking into account operational conditions only these characteristics demand for and allow flexible piping design. The overestimation of the damage potential of seismic loading by e.g. improper failure criteria usually contradicts operational needs producing the known result of excessive ''snubberism'' and reduction of operational margins. As a matter of fact, due to its transiency seismic loading is essentially secondary provoking the natural design requirement ductility instead of stiffness and rigidity - i.e. exclusion of failure by strain control instead of stress control - and thus avoiding the LMFBR typical competition between operational needs and seismic qualification. The design requirement ductility needs judgement mechanisms, i.e. suitable load descriptions, allowed strain levels and strain evaluation tools. A simplified method for strain range estimation and the underlying basic ideas are roughly outlined. The status of verification and experience gained so far is described. The results achieved suggest that the qualification of piping based on ductility requirement controlled by strain criteria is not out of reach. (author)

  17. Systems and Methods for Implementing Bulk Metallic Glass-Based Strain Wave Gears and Strain Wave Gear Components (United States)

    Hofmann, Douglas C. (Inventor); Wilcox, Brian (Inventor)


    Bulk metallic glass-based strain wave gears and strain wave gear components. In one embodiment, a strain wave gear includes: a wave generator; a flexspline that itself includes a first set of gear teeth; and a circular spline that itself includes a second set of gear teeth; where at least one of the wave generator, the flexspline, and the circular spline, includes a bulk metallic glass-based material.

  18. Towards Scalable Strain Gauge-Based Joint Torque Sensors (United States)

    D’Imperio, Mariapaola; Cannella, Ferdinando; Caldwell, Darwin G.; Cuschieri, Alfred


    During recent decades, strain gauge-based joint torque sensors have been commonly used to provide high-fidelity torque measurements in robotics. Although measurement of joint torque/force is often required in engineering research and development, the gluing and wiring of strain gauges used as torque sensors pose difficulties during integration within the restricted space available in small joints. The problem is compounded by the need for a scalable geometric design to measure joint torque. In this communication, we describe a novel design of a strain gauge-based mono-axial torque sensor referred to as square-cut torque sensor (SCTS), the significant features of which are high degree of linearity, symmetry, and high scalability in terms of both size and measuring range. Most importantly, SCTS provides easy access for gluing and wiring of the strain gauges on sensor surface despite the limited available space. We demonstrated that the SCTS was better in terms of symmetry (clockwise and counterclockwise rotation) and more linear. These capabilities have been shown through finite element modeling (ANSYS) confirmed by observed data obtained by load testing experiments. The high performance of SCTS was confirmed by studies involving changes in size, material and/or wings width and thickness. Finally, we demonstrated that the SCTS can be successfully implementation inside the hip joints of miniaturized hydraulically actuated quadruped robot-MiniHyQ. This communication is based on work presented at the 18th International Conference on Climbing and Walking Robots (CLAWAR). PMID:28820446

  19. Bridge condition assessment based on long-term strain monitoring (United States)

    Sun, LiMin; Sun, Shouwang


    In consideration of the important role that bridges play as transportation infrastructures, their safety, durability and serviceability have always been deeply concerned. Structural Health Monitoring Systems (SHMS) have been installed to many long-span bridges to provide bridge engineers with the information needed in making rational decisions for maintenance. However, SHMS also confronted bridge engineers with the challenge of efficient use of monitoring data. Thus, methodologies which are robust to random disturbance and sensitive to damage become a subject on which many researches in structural condition assessment concentrate. In this study, an innovative probabilistic approach for condition assessment of bridge structures was proposed on the basis of long-term strain monitoring on steel girder of a cable-stayed bridge. First, the methodology of damage detection in the vicinity of monitoring point using strain-based indices was investigated. Then, the composition of strain response of bridge under operational loads was analyzed. Thirdly, the influence of temperature and wind on strains was eliminated and thus strain fluctuation under vehicle loads is obtained. Finally, damage evolution assessment was carried out based on the statistical characteristics of rain-flow cycles derived from the strain fluctuation under vehicle loads. The research conducted indicates that the methodology proposed is qualified for structural condition assessment so far as the following respects are concerned: (a) capability of revealing structural deterioration; (b) immunity to the influence of environmental variation; (c) adaptability to the random characteristic exhibited by long-term monitoring data. Further examination of the applicability of the proposed methodology in aging bridge may provide a more convincing validation.

  20. The role of GAGE cancer/testis antigen in metastasis

    DEFF Research Database (Denmark)

    Gjerstorff, Morten Frier; Terp, Mikkel Green; Hansen, Malene Bredahl


    with migratory and invasive properties and were found to be upregulated in cancer cells with metastasizing potential in a gastric cancer model. METHODS: We have addressed the direct role of GAGE proteins in supporting metastasis using an isogenic metastasis model of human cancer, consisting of 4 isogenic cell......) and moderately metastatic clones (LM3), stable downregulation of GAGE expression did not affect the ability of CL16 cells to establish primary tumors and form metastasis in the lungs of immunodeficient mice. CONCLUSIONS: These results suggest that GAGE proteins per se do not support metastasis and that further...

  1. Data acquisition from vacuum gage controlled by RS-232 standard using LabVIEW

    International Nuclear Information System (INIS)

    Brandea, Iulian; Culcer, Mihai; Steflea, Dumitru


    This paper deals with the problem of connecting a microcontroller-based vacuum gage to a personal computer, using the RS-232 hardware standard and the software LabVIEW and his collection of virtual instruments from National Instruments. To solve the problem an instrument driver was created. This provided the customer with a perfect solution for the remote control and data acquisition from an Intel 80CXX microcontroller-based vacuum gage. The remote control making use of an IBM-PC was design and manufactured in our institute. In order to make it intelligent the device was provided with a microprocessor or a microcontroller. To fulfill the requirements a vacuum gage with an 80C31 microcontroller and two Bayard-Alpert ion gauges, for very low pressures (10 -3 to 10 -7 mbar) and low pressure (10 mbar to 10 -3 mbar) was built. Because this microcontroller has a built-in circuitry for a serial communication, we established a serial communication between the PC (Pentium -166 MHz) and the vacuum gage, according to the RS-232 hardware standard. Optimum selection of software development tools however, was not as straightforward. Most producers use the C/C ++ - language programming tool for developing instrument drivers for their intelligent devices. One of the advantages of C/C ++ is its speed, but the compilation and the high-level skill required for optimum programming do not fit well with some requirements, particularly those of versatility, upgradability and user friendliness. After careful evaluation of several options, a final decision was to develop a hybrid software package using two different software development tools: LabVIEW, and assembly language. We chose LabVIEW because it is dedicated to data acquisition and communications, containing libraries for data collection, analysis, presentation and storage. The assembly language for Intel 8051's microcontrollers family is used to write the firmware for the vacuum gage and arithmetic routines. (authors)

  2. Vision system for dial gage torque wrench calibration (United States)

    Aggarwal, Neelam; Doiron, Theodore D.; Sanghera, Paramjeet S.


    In this paper, we present the development of a fast and robust vision system which, in conjunction with the Dial Gage Calibration system developed by AKO Inc., will be used by the U.S. Army in calibrating dial gage torque wrenches. The vision system detects the change in the angular position of the dial pointer in a dial gage. The angular change is proportional to the applied torque. The input to the system is a sequence of images of the torque wrench dial gage taken at different dial pointer positions. The system then reports the angular difference between the different positions. The primary components of this vision system include modules for image acquisition, linear feature extraction and angle measurements. For each of these modules, several techniques were evaluated and the most applicable one was selected. This system has numerous other applications like vision systems to read and calibrate analog instruments.

  3. A new strain based brick element for plate bending

    Directory of Open Access Journals (Sweden)

    L. Belounar


    Full Text Available This paper presents the development of a new three-dimensional brick finite element by the use of the strain based approach for the linear analysis of plate bending. The developed element has the three essential external degrees of freedom (U, V and W at each of the eight corner nodes as well as at the centroidal node. The displacement field of the developed element is based on assumed functions for the various strains satisfying the compatibility equations and the static condensation technique is used for the internal node. The performance of this element is evaluated on several problems related to thick and thin plate bending in linear analysis. The obtained results show the good performances and accuracy of the present element.

  4. Flexible textile-based strain sensor induced by contacts

    International Nuclear Information System (INIS)

    Zhang, Hui


    In this paper, the contact effects are used as the key sensing element to develop flexible textile-structured strain sensors. The structures of the contact are analyzed theoretically and the contact resistances are investigated experimentally. The electromechanical properties of the textiles are investigated to find the key factors which determine the sensitivity, repeatability, and linearity of the sensor. The sensing mechanism is based on the change of contact resistance induced by the change of the configuration of the textiles. In order to improve the performance of the textile strain sensor, the contact resistance is designed based on the electromechanical properties of the fabric. It can be seen from the results that the performance of the sensor is largely affected by the structure of the contacts, which are determined by the morphology of fiber surface and the structures of the yarn and fabric. (paper)

  5. Analysis of strain distribution and critical current of superconductors based on a strain-critical current measurement system

    International Nuclear Information System (INIS)

    Liu Fang; Wu Yu; Long Feng


    Based on Pacman device which is widely used to investigate the axial strain dependence of the critical current in superconductors, the finite element analysis method is employed to carry out the force analysis of the spring and the superconducting strand, thereby the axial and lateral strain distributions of the superconducting strand are obtained. According to the two extreme assumptions(low inter-filament resistance and high inter-filament resistance), the effects of the strain homogeneity at the cross section of the superconductor on the critical current is analyzed combined with the Nb 3 Sn deviatoric strain-critical current scaling law. (authors)

  6. Rapid discrimination of strain-dependent fermentation characteristics among Lactobacillus strains by NMR-based metabolomics of fermented vegetable juice.

    Directory of Open Access Journals (Sweden)

    Satoru Tomita

    Full Text Available In this study, we investigated the applicability of NMR-based metabolomics to discriminate strain-dependent fermentation characteristics of lactic acid bacteria (LAB, which are important microorganisms for fermented food production. To evaluate the discrimination capability, six type strains of Lactobacillus species and six additional L. brevis strains were used focusing on i the difference between homo- and hetero-lactic fermentative species and ii strain-dependent characteristics within L. brevis. Based on the differences in the metabolite profiles of fermented vegetable juices, non-targeted principal component analysis (PCA clearly separated the samples into those inoculated with homo- and hetero-lactic fermentative species. The separation was primarily explained by the different levels of dominant metabolites (lactic acid, acetic acid, ethanol, and mannitol. Orthogonal partial least squares discrimination analysis, based on a regions-of-interest (ROIs approach, revealed the contribution of low-abundance metabolites: acetoin, phenyllactic acid, p-hydroxyphenyllactic acid, glycerophosphocholine, and succinic acid for homolactic fermentation; and ornithine, tyramine, and γ-aminobutyric acid (GABA for heterolactic fermentation. Furthermore, ROIs-based PCA of seven L. brevis strains separated their strain-dependent fermentation characteristics primarily based on their ability to utilize sucrose and citric acid, and convert glutamic acid and tyrosine into GABA and tyramine, respectively. In conclusion, NMR metabolomics successfully discriminated the fermentation characteristics of the tested strains and provided further information on metabolites responsible for these characteristics, which may impact the taste, aroma, and functional properties of fermented foods.

  7. Restriction of GAGE protein expression to subpopulations of cancer cells is independent of genotype and may limit the use of GAGE proteins as targets for cancer immunotherapy

    DEFF Research Database (Denmark)

    Gjerstorff, M F; Johansen, L E; Nielsen, O


    The GAGE cancer testis antigen gene family encodes products that can be recognized by autologous T cells, and GAGE proteins have been suggested as potential targets for cancer immunotherapy. Analysis of GAGE expression in tumours has primarily been performed at the level of gene transcription, wh...

  8. New approach for calibration and interpretation of IRAD GAGE vibrating-wire stressmeters

    International Nuclear Information System (INIS)

    Mao, N.


    IRAD GAGE vibrating-wire stressmeters were installed in the Spent Fuel Facility at the Nevada Test Site to measure the change in in-situ stress during the Spent Fuel Test-Climax (SFT-C). This paper discusses the results of removing a cylindrical section of rock and gages as a unit through overcoring, and the subsequent post-test calibration of the stressmeters in the laboratory. The estimated in-situ stresses based on post test calibration data are quite consistent with those directly measured in nearby holes. The magnitude of stress change calculated from pre-test calibration data is generally much smaller than that estimated from post test calibration data. 11 refs., 5 figs., 2 tabs

  9. The Effect of Modeling Qualities, Tones and Gages in Ceramic Supply Chains' Master Planning

    Directory of Open Access Journals (Sweden)

    Isabel MUNDI


    Full Text Available Ceramic production processes are characterized by providing quantities of the same finished goods that differ in qualities, tones and gages. This aspect becomes a problem for ceramic supply chains (SCs that should promise and serve customer orders with homogeneous quantities of the same finished good. In this paper a mathematical programming model for the cen-tralized master planning of ceramic SC is proposed. Inputs to the master plan include demand forecasts in terms of customer order classes based on their order size and splitting percentages of a lot into homogeneous sub-lots. Then, the master plan defines the size and loading of lots to production lines and their distribution with the aim of maximizing the number of customer orders fulfilled with homogeneous quantities in the most efficient manner for the SC. Finally, the effect of modeling qualities, tones and gages in master planning is assessed.

  10. Tunable strain gauges based on two-dimensional silver nanowire networks

    International Nuclear Information System (INIS)

    Ho, Xinning; Cheng, Chek Kweng; Tey, Ju Nie; Wei, Jun


    Strain gauges are used in various applications such as wearable strain gauges and strain gauges in airplanes or structural health monitoring. Sensitivity of the strain gauge required varies, depending on the application of the strain gauge. This paper reports a tunable strain gauge based on a two-dimensional percolative network of silver nanowires. By varying the surface coverage of the nanowire network and the waviness of the nanowires in the network, the sensitivity of the strain gauge can be controlled. Hence, a tunable strain gauge can be engineered, based on demands of the application. A few applications are demonstrated. The strain gauge can be adhered to the human neck to detect throat movements and a glove integrated with such a strain gauge can detect the bending of the forefinger. Other classes of two-dimensional percolative networks of one-dimensional materials are also expected to exhibit similar tunable properties. (paper)

  11. Displacement sensing based on modal interference in polymer optical fibers with partially applied strain (United States)

    Mizuno, Yosuke; Hagiwara, Sonoko; Kawa, Tomohito; Lee, Heeyoung; Nakamura, Kentaro


    Strain sensing based on modal interference in multimode fibers (MMFs) has been extensively studied, but no experimental or theoretical reports have been given as to how the system works when strain is applied not to the whole MMF but only to part of the MMF. Here, using a perfluorinated graded-index polymer optical fiber as the MMF, we investigate the strain sensing characteristics of this type of sensor when strain is partially applied to fiber sections with different lengths. The strain sensitivity dependence on the length of the strained section reveals that this strain sensor actually behaves as a displacement sensor.

  12. Electron transport in gold colloidal nanoparticle-based strain gauges (United States)

    Moreira, Helena; Grisolia, Jérémie; Sangeetha, Neralagatta M.; Decorde, Nicolas; Farcau, Cosmin; Viallet, Benoit; Chen, Ke; Viau, Guillaume; Ressier, Laurence


    A systematic approach for understanding the electron transport mechanisms in resistive strain gauges based on assemblies of gold colloidal nanoparticles (NPs) protected by organic ligands is described. The strain gauges were fabricated from parallel micrometer wide wires made of 14 nm gold (Au) colloidal NPs on polyethylene terephthalate substrates, elaborated by convective self-assembly. Electron transport in such devices occurs by inter-particle electron tunneling through the tunnel barrier imposed by the organic ligands protecting the NPs. This tunnel barrier was varied by changing the nature of organic ligands coating the nanoparticles: citrate (CIT), phosphines (BSPP, TDSP) and thiols (MPA, MUDA). Electro-mechanical tests indicate that only the gold NPs protected by phosphine and thiol ligands yield high gauge sensitivity. Temperature-dependent resistance measurements are explained using the ‘regular island array model’ that extracts transport parameters, i.e., the tunneling decay constant β and the Coulomb charging energy EC. This reveals that the Au@CIT nanoparticle assemblies exhibit a behavior characteristic of a strong-coupling regime, whereas those of Au@BSPP, Au@TDSP, Au@MPA and Au@MUDA nanoparticles manifest a weak-coupling regime. A comparison of the parameters extracted from the two methods indicates that the most sensitive gauges in the weak-coupling regime feature the highest β. Moreover, the EC values of these 14 nm NPs cannot be neglected in determining the β values.

  13. An Embeddable Strain Sensor with 30 Nano-Strain Resolution Based on Optical Interferometry

    Directory of Open Access Journals (Sweden)

    Chen Zhu


    Full Text Available A cost-effective, robust and embeddable optical interferometric strain sensor with nanoscale strain resolution is presented in this paper. The sensor consists of an optical fiber, a quartz rod with one end coated with a thin gold layer, and two metal shells employed to transfer the strain and orient and protect the optical fiber and the quartz rod. The optical fiber endface, combining with the gold-coated surface, forms an extrinsic Fabry–Perot interferometer. The sensor was firstly calibrated, and the result showed that our prototype sensor could provide a measurement resolution of 30 nano-strain (nε and a sensitivity of 10.01 µε/µm over a range of 1000 µε. After calibration of the sensor, the shrinkage strain of a cubic brick of mortar in real time during the drying process was monitored. The strain sensor was compared with a commercial linear variable displacement transducer, and the comparison results in four weeks demonstrated that our sensor had much higher measurement resolution and gained more detailed and useful information. Due to the advantages of the extremely simple, robust and cost-effective configuration, it is believed that the sensor is significantly beneficial to practical applications, especially for structural health monitoring.

  14. A Review: Carbon Nanotube-Based Piezoresistive Strain Sensors

    Directory of Open Access Journals (Sweden)

    Waris Obitayo


    Full Text Available The use of carbon nanotubes for piezoresistive strain sensors has acquired significant attention due to its unique electromechanical properties. In this comprehensive review paper, we discussed some important aspects of carbon nanotubes for strain sensing at both the nanoscale and macroscale. Carbon nanotubes undergo changes in their band structures when subjected to mechanical deformations. This phenomenon makes them applicable for strain sensing applications. This paper signifies the type of carbon nanotubes best suitable for piezoresistive strain sensors. The electrical resistivities of carbon nanotube thin film increase linearly with strain, making it an ideal material for a piezoresistive strain sensor. Carbon nanotube composite films, which are usually fabricated by mixing small amounts of single-walled or multiwalled carbon nanotubes with selected polymers, have shown promising characteristics of piezoresistive strain sensors. Studies also show that carbon nanotubes display a stable and predictable voltage response as a function of temperature.

  15. Effects of C and Si on strain aging of strain-based API X60 pipeline steels (United States)

    Sung, Hyo Kyung; Lee, Dong Ho; Lee, Sunghak; Lee, Byeong-Joo; Hong, Seung-Pyo; Kim, Young-Woon; Yoo, Jang Yong; Hwang, Byoungchul; Shin, Sang Yong


    Four types of strain-based API X60 pipeline steels were fabricated by varying the C and Si contents, and the effects of C and Si on strain aging were investigated. The 0.05 wt% C steels consisted mainly of polygonal ferrite (PF), whereas the 0.08 wt% C steels consisted of acicular ferrite (AF). The volume fraction of AF increased with increasing C content because C is an austenite stabilizer element. The volume fractions of bainitic ferrite (BF) of the 0.15 wt% Si steels were higher than those of the 0.25 wt% Si steels, whereas the volume fractions of the secondary phases were lower. From the tensile properties before and after the aging process of the strainbased API X60 pipeline steels, the yield strength increased and the uniform and total elongation decreased, which is the strain aging effect. The strain aging effect in the strain-based API X60 pipeline steels was minimized when the volume fraction of AF was increased and secondary phases were distributed uniformly. On the other hand, an excessively high C content formed fine precipitates, and the strain aging effect occurred because of the interactions among dislocations and fine precipitates.

  16. Development and application of the variable focus laser leveling gage

    International Nuclear Information System (INIS)

    Gong Kun; Ma Jinglong


    The variable focus laser leveling gage was developed. The performance and structure were introduced. The several alignments and tests in KrF laser angle multi-path optical system were accomplished with them. Its application in other optical equipment was discussed too. (author)

  17. Latin-square three-dimensional gage master (United States)

    Jones, L.


    A gage master for coordinate measuring machines has an nxn array of objects distributed in the Z coordinate utilizing the concept of a Latin square experimental design. Using analysis of variance techniques, the invention may be used to identify sources of error in machine geometry and quantify machine accuracy.

  18. 49 CFR 213.110 - Gage restraint measurement systems. (United States)


    ... requirements specified in §§ 213.109 and 213.127. (5) If the PTLF becomes non-functional or is missing, the... and fastener requirements specified in §§ 213.109 and 213.127 provided that— (1) The track owner... the minimum design requirements of a GRMS vehicle which specify that— (1) Gage restraint shall be...

  19. Comparison of NEXRAD multisensor precipitation estimates to rain gage observations in and near DuPage County, Illinois, 2002–12 (United States)

    Spies, Ryan R.; Over, Thomas M.; Ortel, Terry W.


    In this report, precipitation data from 2002 to 2012 from the hourly gridded Next-Generation Radar (NEXRAD)-based Multisensor Precipitation Estimate (MPE) precipitation product are compared to precipitation data from two rain gage networks—an automated tipping bucket network of 25 rain gages operated by the U.S. Geological Survey (USGS) and 51 rain gages from the volunteer-operated Community Collaborative Rain, Hail, and Snow (CoCoRaHS) network—in and near DuPage County, Illinois, at a daily time step to test for long-term differences in space, time, and distribution. The NEXRAD–MPE data that are used are from the fifty 2.5-mile grid cells overlying the rain gages from the other networks. Because of the challenges of measuring of frozen precipitation, the analysis period is separated between days with or without the chance of freezing conditions. The NEXRAD–MPE and tipping-bucket rain gage precipitation data are adjusted to account for undercatch by multiplying by a previously determined factor of 1.14. Under nonfreezing conditions, the three precipitation datasets are broadly similar in cumulative depth and distribution of daily values when the data are combined spatially across the networks. However, the NEXRAD–MPE data indicate a significant trend relative to both rain gage networks as a function of distance from the NEXRAD radar just south of the study area. During freezing conditions, of the USGS network rain gages only the heated gages were considered, and these gages indicate substantial mean undercatch of 50 and 61 percent compared to the NEXRAD–MPE and the CoCoRaHS gages, respectively. The heated USGS rain gages also indicate substantially lower quantile values during freezing conditions, except during the most extreme (highest) events. Because NEXRAD precipitation products are continually evolving, the report concludes with a discussion of recent changes in those products and their potential for improved precipitation estimation. An appendix

  20. Use of colony-based bacterial strain typing for tracking the fate of Lactobacillus strains during human consumption

    Directory of Open Access Journals (Sweden)

    Drevinek Pavel


    Full Text Available Abstract Background The Lactic Acid Bacteria (LAB are important components of the healthy gut flora and have been used extensively as probiotics. Understanding the cultivable diversity of LAB before and after probiotic administration, and being able to track the fate of administered probiotic isolates during feeding are important parameters to consider in the design of clinical trials to assess probiotic efficacy. Several methods may be used to identify bacteria at the strain level, however, PCR-based methods such as Random Amplified Polymorphic DNA (RAPD are particularly suited to rapid analysis. We examined the cultivable diversity of LAB in the human gut before and after feeding with two Lactobacillus strains, and also tracked the fate of these two administered strains using a RAPD technique. Results A RAPD typing scheme was developed to genetically type LAB isolates from a wide range of species, and optimised for direct application to bacterial colony growth. A high-throughput strategy for fingerprinting the cultivable diversity of human faeces was developed and used to determine: (i the initial cultivable LAB strain diversity in the human gut, and (ii the fate of two Lactobacillus strains (Lactobacillus salivarius NCIMB 30211 and Lactobacillus acidophilus NCIMB 30156 contained within a capsule that was administered in a small-scale human feeding study. The L. salivarius strain was not cultivated from the faeces of any of the 12 volunteers prior to capsule administration, but appeared post-feeding in four. Strains matching the L. acidophilus NCIMB 30156 feeding strain were found in the faeces of three volunteers prior to consumption; after taking the Lactobacillus capsule, 10 of the 12 volunteers were culture positive for this strain. The appearance of both Lactobacillus strains during capsule consumption was statistically significant (p Conclusion We have shown that genetic strain typing of the cultivable human gut microbiota can be

  1. Development of piping strain sensor for stress evaluation

    International Nuclear Information System (INIS)

    Takahama, Tsunemichi; Nishimura, Kazuma; Ninomiya, Seiichiro; Matsumoto, Yoshihiro; Harada, Yutaka


    In a small diameter piping, stresses are generated due to internal fluid or pump vibrations especially around the welding parts. Authors have successfully developed a pipe strain sensor which is able to measure such stresses. Unlike conventional methods using strain gages and adhesive bond, the sensor can measure the strain without putting adhesive bond on the piping surface. However, the strain sensor can provide measurements with a level of accuracy equivalent to that of conventional method using strain gages and adhesive bond. Accordingly, the strain sensor can significantly reduce the working time without any loss of the measurement accuracy. (author)

  2. Sleep monitoring sensor using flexible metal strain gauge (United States)

    Kwak, Yeon Hwa; Kim, Jinyong; Kim, Kunnyun


    This paper presents a sleep monitoring sensor based on a flexible metal strain gauge. As quality of life has improved, interest in sleep quality, and related products, has increased. In this study, unlike a conventional single sensor based on a piezoelectric material, a metal strain gauge-based array sensor based on polyimide and nickel chromium (NiCr) is applied to provide movement direction, respiration, and heartbeat data as well as contact-free use by the user during sleeping. Thin-film-type resistive strain gage sensors are fabricated through the conventional flexible printed circuit board (FPCB) process, which is very useful for commercialization. The measurement of movement direction and respiratory rate during sleep were evaluated, and the heart rate data were compared with concurrent electrocardiogram (ECG) data. An algorithm for analyzing sleep data was developed using MATLAB, and the error rate was 4.2% when compared with ECG for heart rate.

  3. Highly sensitive strain sensors based on fragmentized carbon nanotube/polydimethylsiloxane composites (United States)

    Gao, Yang; Fang, Xiaoliang; Tan, Jianping; Lu, Ting; Pan, Likun; Xuan, Fuzhen


    Wearable strain sensors based on nanomaterial/elastomer composites have potential applications in flexible electronic skin, human motion detection, human–machine interfaces, etc. In this research, a type of high performance strain sensors has been developed using fragmentized carbon nanotube/polydimethylsiloxane (CNT/PDMS) composites. The CNT/PDMS composites were ground into fragments, and a liquid-induced densification method was used to fabricate the strain sensors. The strain sensors showed high sensitivity with gauge factors (GFs) larger than 200 and a broad strain detection range up to 80%, much higher than those strain sensors based on unfragmentized CNT/PDMS composites (GF composite particles during mechanical deformation, which causes significant resistance change in the strain sensors. The strain sensors can differentiate mechanical stimuli and monitor various human body motions, such as bending of the fingers, human breathing, and blood pulsing.

  4. Highly sensitive strain sensors based on fragmentized carbon nanotube/polydimethylsiloxane composites. (United States)

    Gao, Yang; Fang, Xiaoliang; Tan, Jianping; Lu, Ting; Pan, Likun; Xuan, Fuzhen


    Wearable strain sensors based on nanomaterial/elastomer composites have potential applications in flexible electronic skin, human motion detection, human-machine interfaces, etc. In this research, a type of high performance strain sensors has been developed using fragmentized carbon nanotube/polydimethylsiloxane (CNT/PDMS) composites. The CNT/PDMS composites were ground into fragments, and a liquid-induced densification method was used to fabricate the strain sensors. The strain sensors showed high sensitivity with gauge factors (GFs) larger than 200 and a broad strain detection range up to 80%, much higher than those strain sensors based on unfragmentized CNT/PDMS composites (GF sensors is ascribed to the sliding of individual fragmentized-CNT/PDMS-composite particles during mechanical deformation, which causes significant resistance change in the strain sensors. The strain sensors can differentiate mechanical stimuli and monitor various human body motions, such as bending of the fingers, human breathing, and blood pulsing.

  5. Annealing effects on strain and stress sensitivity of polymer optical fibre based sensors

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A. F.; Zubel, M. G.


    The annealing effects on strain and stress sensitivity of polymer optical fibre Bragg grating sensors after their photoinscription are investigated. PMMA optical fibre based Bragg grating sensors are first photo-inscribed and then they were placed into hot water for annealing. Strain, stress...... fibre tends to increase the strain, stress and force sensitivity of the photo-inscribed sensor....

  6. Towards highly sensitive strain sensing based on nanostructured materials

    International Nuclear Information System (INIS)

    Dao, Dzung Viet; Nakamura, Koichi; Sugiyama, Susumu; Bui, Tung Thanh; Dau, Van Thanh; Yamada, Takeo; Hata, Kenji


    This paper presents our recent theoretical and experimental study of piezo-effects in nanostructured materials for highly sensitive, high resolution mechanical sensors. The piezo-effects presented here include the piezoresistive effect in a silicon nanowire (SiNW) and single wall carbon nanotube (SWCNT) thin film, as well as the piezo-optic effect in a Si photonic crystal (PhC) nanocavity. Firstly, the electronic energy band structure of the silicon nanostructure is discussed and simulated by using the First-Principles Calculations method. The result showed a remarkably different energy band structure compared with that of bulk silicon. This difference in the electronic state will result in different physical, chemical, and therefore, sensing properties of silicon nanostructures. The piezoresistive effects of SiNW and SWCNT thin film were investigated experimentally. We found that, when the width of ( 110 ) p-type SiNW decreases from 500 to 35 nm, the piezoresistive effect increases by more than 60%. The longitudinal piezoresistive coefficient of SWCNT thin film was measured to be twice that of bulk p-type silicon. Finally, theoretical investigations of the piezo-optic effect in a PhC nanocavity based on Finite Difference Time Domain (FDTD) showed extremely high resolution strain sensing. These nanostructures were fabricated based on top-down nanofabrication technology. The achievements of this work are significant for highly sensitive, high resolution and miniaturized mechanical sensors

  7. Polymer film strain gauges for measuring large elongations (United States)

    Kondratov, A. P.; Zueva, A. M.; Varakin, R. S.; Taranec, I. P.; Savenkova, I. A.


    The paper shows the possibility to print polymer strain gages, microstrip lines, coplanar waveguides, and other prints for avionics using printing technology and equipment. The methods of screen and inkjet printing have been complemented by three new operations of preparing print films for application of an electrically conductive ink layer. Such additional operations make it possible to enhance the conductive ink layer adhesion to the film and to manufacture strain gages for measuring large elongations.

  8. Comparison of stress-based and strain-based creep failure criteria for severe accident analysis

    International Nuclear Information System (INIS)

    Chavez, S.A.; Kelly, D.L.; Witt, R.J.; Stirn, D.P.


    We conducted a parametic analysis of stress-based and strain-based creep failure criteria to determine if there is a significant difference between the two criteria for SA533B vessel steel under severe accident conditions. Parametric variables include debris composition, system pressure, and creep strain histories derived from different testing programs and mathematically fit, with and without tertiary creep. Results indicate significant differences between the two criteria. Stress gradient plays an important role in determining which criterion will predict failure first. Creep failure was not very sensitive to different creep strain histories, except near the transition temperature of the vessel steel (900K to 1000K). Statistical analyses of creep failure data of four independent sources indicate that these data may be pooled, with a spline point at 1000K. We found the Manson-Haferd parameter to have better failure predictive capability than the Larson-Miller parameter for the data studied. (orig.)

  9. New constraints on slip rates and locking depths of the San Andreas Fault System from Sentinel-1A InSAR and GAGE GPS observations (United States)

    Ward, L. A.; Smith-Konter, B. R.; Higa, J. T.; Xu, X.; Tong, X.; Sandwell, D. T.


    After over a decade of operation, the EarthScope (GAGE) Facility has now accumulated a wealth of GPS and InSAR data, that when successfully integrated, make it possible to image the entire San Andreas Fault System (SAFS) with unprecedented spatial coverage and resolution. Resulting surface velocity and deformation time series products provide critical boundary conditions needed for improving our understanding of how faults are loaded across a broad range of temporal and spatial scales. Moreover, our understanding of how earthquake cycle deformation is influenced by fault zone strength and crust/mantle rheology is still developing. To further study these processes, we construct a new 4D earthquake cycle model of the SAFS representing the time-dependent 3D velocity field associated with interseismic strain accumulation, co-seismic slip, and postseismic viscoelastic relaxation. This high-resolution California statewide model, spanning the Cerro Prieto fault to the south to the Maacama fault to the north, is constructed on a 500 m spaced grid and comprises variable slip and locking depths along 42 major fault segments. Secular deep slip is prescribed from the base of the locked zone to the base of the elastic plate while episodic shallow slip is prescribed from the historical earthquake record and geologic recurrence intervals. Locking depths and slip rates for all 42 fault segments are constrained by the newest GAGE Facility geodetic observations; 3169 horizontal GPS velocity measurements, combined with over 53,000 line-of-sight (LOS) InSAR velocity observations from Sentinel-1A, are used in a weighted least-squares inversion. To assess slip rate and locking depth sensitivity of a heterogeneous rheology model, we also implement variations in crustal rigidity throughout the plate boundary, assuming a coarse representation of shear modulus variability ranging from 20-40 GPa throughout the (low rigidity) Salton Trough and Basin and Range and the (high rigidity) Central

  10. Two New Quadrilateral Elements Based on Strain States

    Directory of Open Access Journals (Sweden)

    Mohammad Rezaiee-Pajand


    Full Text Available In this paper, two new quadrilateral elements are formulated to solve plane problems. Low sensitivity to geometric distortion, no parasitic shear error, rotational invariance, and satisfying the Felippa pure bending test are characteristics of these suggested elements. One proposed element is formulated by establishing equilibrium equations for the second-order strain field. The other suggested element is obtained by establishing equilibrium equations only for the linear part of the strain field. The number of the strain states decreases when the conditions among strain states are satisfied. Several numerical tests are used to demonstrate the performance of the proposed elements. Famous elements, which were suggested by other researchers, are used as a means of comparison. It is shown that these novel elements pass the strong patch tests, even for extremely poor meshes, and one of them has an excellent accuracy and fast convergence in other complicated problems.

  11. Nano-resonator frequency response based on strain gradient theory

    International Nuclear Information System (INIS)

    Miandoab, Ehsan Maani; Yousefi-Koma, Aghil; Pishkenari, Hossein Nejat; Fathi, Mohammad


    This paper aims to explore the dynamic behaviour of a nano-resonator under ac and dc excitation using strain gradient theory. To achieve this goal, the partial differential equation of nano-beam vibration is first converted to an ordinary differential equation by the Galerkin projection method and the lumped model is derived. Lumped parameters of the nano-resonator, such as linear and nonlinear springs and damper coefficients, are compared with those of classical theory and it is demonstrated that beams with smaller thickness display greater deviation from classical parameters. Stable and unstable equilibrium points based on classic and non-classical theories are also compared. The results show that, regarding the applied dc voltage, the dynamic behaviours expected by classical and non-classical theories are significantly different, such that one theory predicts the un-deformed shape as the stable condition, while the other theory predicts that the beam will experience bi-stability. To obtain the frequency response of the nano-resonator, a general equation including cubic and quadratic nonlinearities in addition to parametric electrostatic excitation terms is derived, and the analytical solution is determined using a second-order multiple scales method. Based on frequency response analysis, the softening and hardening effects given by two theories are investigated and compared, and it is observed that neglecting the size effect can lead to two completely different predictions in the dynamic behaviour of the resonators. The findings of this article can be helpful in the design and characterization of the size-dependent dynamic behaviour of resonators on small scales. (paper)

  12. Skin-friction measurements with hot-wire gages (United States)

    Houdeville, R.; Juillen, J. C.; Cousteix, J.


    The development of two hot-wire gauges for implantation in wind-tunnel models and their application to the measurement of skin-friction phenomena are reported. The measurement principle is explained; the design and calibration of a single-wire gage containing a thermocouple for temperature determination (Cousteix and Juillen, 1982-1983) are summarized; and sample results for 2D and 3D flows with positive pressure gradients are shown. An advanced design employing a thin hot film deposited on an 80-micron-diameter quartz fiber extending into a 1-mm-sq 0.8-mm-deep cavity is characterized and demonstrated on a pulsed flow on a flat plate, Tollmien-Schlichting waves, and a turbulent boundary layer. Two cold-wire temperature sensors are added to this gage to permit detection of the skin of the skin friction in the separated flow over a cylinder.

  13. Estimation of piping temperature fluctuations based on external strain measurements

    International Nuclear Information System (INIS)

    Morilhat, P.; Maye, J.P.


    Due to the difficulty to carry out measurements at the inner sides of nuclear reactor piping subjected to thermal transients, temperature and stress variations in the pipe walls are estimated by means of external thermocouples and strain-gauges. This inverse problem is solved by spectral analysis. Since the wall harmonic transfer function (response to a harmonic load) is known, the inner side signal will be obtained by convolution of the inverse transfer function of the system and of the strain measurement enables detection of internal temperature fluctuations in a frequency range beyond the scope of the thermocouples. (authors). 5 figs., 3 refs

  14. Dielectrophoresis-based discrimination of bacteria at the strain level based on their surface properties.

    Directory of Open Access Journals (Sweden)

    William A Braff

    Full Text Available Insulator-based dielectrophoresis can be used to manipulate biological particles, but has thus far found limited practical applications due to low sensitivity. We present linear sweep three-dimensional insulator-based dielectrophoresis as a considerably more sensitive approach for strain-level discrimination bacteria. In this work, linear sweep three-dimensional insulator-based dielectrophoresis was performed on Pseudomonas aeruginosa PA14 along with six isogenic mutants as well as Streptococcus mitis SF100 and PS344. Strain-level discrimination was achieved between these clinically important pathogens with applied electric fields below 10 V/mm. This low voltage, high sensitivity technique has potential applications in clinical diagnostics as well as microbial physiology research.

  15. Measurement of strains at high temperatures by means of electro-optics holography (United States)

    Sciammarella, Cesar A.; Bhat, G.; Vaitekunas, Jeffrey

    Electro-optics holographic-moire interferometry is used to measure strains at temperatures up to 1000 C. A description of the instrumentation developed to carry out the measurements is given. The data processing technique is also explained. Main problems encountered in recording patterns at high temperatures are analyzed and possible solutions are outlined. Optical results are compared with strain gage values obtained with instrumented specimens and with theoretical results. Very good agreement is found between optical, strain gage and theoretical results.

  16. Metallic nanoparticle-based strain sensors elaborated by atomic layer deposition (United States)

    Puyoo, E.; Malhaire, C.; Thomas, D.; Rafaël, R.; R'Mili, M.; Malchère, A.; Roiban, L.; Koneti, S.; Bugnet, M.; Sabac, A.; Le Berre, M.


    Platinum nanoparticle-based strain gauges are elaborated by means of atomic layer deposition on flexible polyimide substrates. Their electro-mechanical response is tested under mechanical bending in both buckling and conformational contact configurations. A maximum gauge factor of 70 is reached at a strain level of 0.5%. Although the exponential dependence of the gauge resistance on strain is attributed to the tunneling effect, it is shown that the majority of the junctions between adjacent Pt nanoparticles are in a short circuit state. Finally, we demonstrate the feasibility of an all-plastic pressure sensor integrating Pt nanoparticle-based strain gauges in a Wheatstone bridge configuration.

  17. Strain sensor system based on amorphous ferromagnetic ribbons

    Czech Academy of Sciences Publication Activity Database

    Jančárik, V.; Švec, P.; Kraus, Luděk


    Roč. 53, 10/S (2002), s. 92-94 ISSN 1335-3632. [Magnetic Measurements'02. Bratislava, 11.09.2002-13.09.2002] Grant - others:NATO(XX) SfP 973649 Institutional research plan: CEZ:AV0Z1010914 Keywords : strain sensor * magnetoelastic effect * amorphous ferromagnetic Subject RIV: BM - Solid Matter Physics ; Magnetism

  18. DNA-based identification of Lentinula edodes strains with species ...

    African Journals Online (AJOL)



    Feb 17, 2016 ... Received 7 November, 2015; Accepted 25 January, 2016. Lentinula edodes is among the five globally cultivated ... through polymerase chain reaction (PCR). As a prelude to additional nutritional and .... Eleven (11) strains of shiitake, namely LE005 (ATTC #28759),. LE006 (ATTC# 28760), LE 008 (ATTC# ...

  19. Strained superlattices and magnetic tunnel junctions based on doped manganites

    International Nuclear Information System (INIS)

    Yafeng Lu


    In the first part of this work the effect of biaxial strain on the structure and transport properties of doped manganites has been studied to explore the relevance of Jahn-Teller electron-lattice interaction for the CMR phenomenon in these materials. A series of high quality, coherently strained La 2/3 (Ca or Ba) 1/3 MnO 3 /SrTiO 3 superlattices with different modulation periods have been fabricated on (001) SrTiO 3 and NdGaO 3 substrates by laser molecular beam epitaxy. A detailed structural characterization was performed by high-angle X-ray diffraction (HAXRD) and low-angle X-ray reflectivity (LAXRR). The fabricated superlattices are very flat, show excellent structural coherence and very small mosaic spread (0.2 ∝0.03 ). The in-plane coherency strain could be varied by changing the thickness ratio of the constituent layers allowing for a systematic variation of the resulting lattice distortion of La 2/3 (Ca or Ba) 1/3 MnO 3 . By the in-plane coherency strain the out-of-plane lattice constant could be continuously adjusted by varying the relative thickness of the SrTiO 3 and La 2/3 (Ca or Ba) 1/3 MnO 3 layers: the c-axis lattice constant of La 2/3 Ba 1/3 MnO 3 was found to vary from 3.910 A to 3.975 A due to a compressive in-plane strain, whereas the c-axis constant of La 2/3 Ca 1/3 MnO 3 was found to change from 3.87 A to 3.79A due to tensile in-plane strain. The strain results in a biaxial distortion ε bi of La 2/3 (Ca or Ba) 1/3 MnO 3 that strongly affects the electrical transport properties and the magnetoresistance. Our measurements show that there is a clear correlation between ε bi and the temperature T p corresponding to the maximum in the resistivity versus temperature curves as well as the measured magnetoresistance in the two systems. In the second part of this work we have investigated the spin-dependent tunneling in trilayer structures of La 2/3 Ba 1/3 MnO 3 /SrTiO 3 /La 2/3 Ba 1/3 MnO 3 . (orig.)

  20. Establishing a Multi-scale Stream Gaging Network in the Whitewater River Basin, Kansas, USA (United States)

    Clayton, J.A.; Kean, J.W.


    Investigating the routing of streamflow through a large drainage basin requires the determination of discharge at numerous locations in the channel network. Establishing a dense network of stream gages using conventional methods is both cost-prohibitive and functionally impractical for many research projects. We employ herein a previously tested, fluid-mechanically based model for generating rating curves to establish a stream gaging network in the Whitewater River basin in south-central Kansas. The model was developed for the type of channels typically found in this watershed, meaning that it is designed to handle deep, narrow geomorphically stable channels with irregular planforms, and can model overbank flow over a vegetated floodplain. We applied the model to ten previously ungaged stream reaches in the basin, ranging from third- to sixth-order channels. At each site, detailed field measurements of the channel and floodplain morphology, bed and bank roughness, and vegetation characteristics were used to quantify the roughness for a range of flow stages, from low flow to overbank flooding. Rating curves that relate stage to discharge were developed for all ten sites. Both fieldwork and modeling were completed in less than 2 years during an anomalously dry period in the region, which underscores an advantage of using theoretically based (as opposed to empirically based) discharge estimation techniques. ?? 2010 Springer Science+Business Media B.V.

  1. Near Net Manufacturing Using Thin Gage Friction Stir Welding (United States)

    Takeshita, Jennifer; Potter, David; Holquin, Michael


    Friction Stir Welding (FSW) and near net spin forming of FSW aluminumn blanks were investigated for large-scale pressure vessel applications. With a specific focus on very thin gage 2xxx and 7xxx aluminum alloys, the program concentrated on the following: the criteria used for material selection, a potential manufacturing flow, and the effectiveness and associated risks of near net spin forming. Discussion will include the mechanical properties of the friction stir welds and the parent material from before and after the spin forming process. This effort was performed under a NASA Space Exploration initiative focused on increasing the affordability, reliability and performance of pressure vessels larger than 10 ft. diameter.

  2. Highly sensitive wearable strain sensor based on silver nanowires and nanoparticles (United States)

    Shengbo, Sang; Lihua, Liu; Aoqun, Jian; Qianqian, Duan; Jianlong, Ji; Qiang, Zhang; Wendong, Zhang


    Here, we propose a highly sensitive and stretchable strain sensor based on silver nanoparticles and nanowires (Ag NPs and NWs), advancing the rapid development of electronic skin. To improve the sensitivity of strain sensors based on silver nanowires (Ag NWs), Ag NPs and NWs were added to polydimethylsiloxane (PDMS) as an aid filler. Silver nanoparticles (Ag NPs) increase the conductive paths for electrons, leading to the low resistance of the resulting sensor (14.9 Ω). The strain sensor based on Ag NPs and NWs showed strong piezoresistivity with a tunable gauge factor (GF) at 3766, and a change in resistance as the strain linearly increased from 0% to 28.1%. The high GF demonstrates the irreplaceable role of Ag NPs in the sensor. Moreover, the applicability of our high-performance strain sensor has been demonstrated by its ability to sense movements caused by human talking, finger bending, wrist raising and walking.

  3. Polydimethylsiloxane (PDMS-Based Flexible Resistive Strain Sensors for Wearable Applications

    Directory of Open Access Journals (Sweden)

    Jing Chen


    Full Text Available There is growing attention and rapid development on flexible electronic devices with electronic materials and sensing technology innovations. In particular, strain sensors with high elasticity and stretchability are needed for several potential applications including human entertainment technology, human–machine interface, personal healthcare, and sports performance monitoring, etc. This article presents recent advancements in the development of polydimethylsiloxane (PDMS-based flexible resistive strain sensors for wearable applications. First of all, the article shows that PDMS-based stretchable resistive strain sensors are successfully fabricated by different methods, such as the filtration method, printing technology, micromolding method, coating techniques, and liquid phase mixing. Next, strain sensing performances including stretchability, gauge factor, linearity, and durability are comprehensively demonstrated and compared. Finally, potential applications of PDMS-based flexible resistive strain sensors are also discussed. This review indicates that the era of wearable intelligent electronic systems has arrived.

  4. Optical fiber strain sensor using fiber resonator based on frequency comb Vernier spectroscopy

    DEFF Research Database (Denmark)

    Zhang, Liang; Lu, Ping; Chen, Li


    A novel (to our best knowledge) optical fiber strain sensor using a fiber ring resonator based on frequency comb Vernier spectroscopy is proposed and demonstrated. A passively mode-locked optical fiber laser is employed to generate a phased-locked frequency comb. Strain applied to the optical fib...

  5. Development of a Waterproof Crack-Based Stretchable Strain Sensor Based on PDMS Shielding. (United States)

    Hong, Seong Kyung; Yang, Seongjin; Cho, Seong J; Jeon, Hyungkook; Lim, Geunbae


    This paper details the design of a poly(dimethylsiloxane) (PDMS)-shielded waterproof crack-based stretchable strain sensor, in which the electrical characteristics and sensing performance are not influenced by changes in humidity. This results in a higher number of potential applications for the sensor. A previously developed omni-purpose stretchable strain (OPSS) sensor was used as the basis for this work, which utilizes a metal cracking structure and provides a wide sensing range and high sensitivity. Changes in the conductivity of the OPSS sensor, based on humidity conditions, were investigated along with the potential possibility of using the design as a humidity sensor. However, to prevent conductivity variation, which can decrease the reliability and sensing ability of the OPSS sensor, PDMS was utilized as a shielding layer over the OPSS sensor. The PDMS-shielded OPSS sensor showed approximately the same electrical characteristics as previous designs, including in a high humidity environment, while maintaining its strain sensing capabilities. The developed sensor shows promise for use under high humidity conditions and in underwater applications. Therefore, considering its unique features and reliable sensing performance, the developed PDMS-shielded waterproof OPSS sensor has potential utility in a wide range of applications, such as motion monitoring, medical robotics and wearable healthcare devices.

  6. Development of a Waterproof Crack-Based Stretchable Strain Sensor Based on PDMS Shielding

    Directory of Open Access Journals (Sweden)

    Seong Kyung Hong


    Full Text Available This paper details the design of a poly(dimethylsiloxane (PDMS-shielded waterproof crack-based stretchable strain sensor, in which the electrical characteristics and sensing performance are not influenced by changes in humidity. This results in a higher number of potential applications for the sensor. A previously developed omni-purpose stretchable strain (OPSS sensor was used as the basis for this work, which utilizes a metal cracking structure and provides a wide sensing range and high sensitivity. Changes in the conductivity of the OPSS sensor, based on humidity conditions, were investigated along with the potential possibility of using the design as a humidity sensor. However, to prevent conductivity variation, which can decrease the reliability and sensing ability of the OPSS sensor, PDMS was utilized as a shielding layer over the OPSS sensor. The PDMS-shielded OPSS sensor showed approximately the same electrical characteristics as previous designs, including in a high humidity environment, while maintaining its strain sensing capabilities. The developed sensor shows promise for use under high humidity conditions and in underwater applications. Therefore, considering its unique features and reliable sensing performance, the developed PDMS-shielded waterproof OPSS sensor has potential utility in a wide range of applications, such as motion monitoring, medical robotics and wearable healthcare devices.

  7. A valley-filtering switch based on strained graphene. (United States)

    Zhai, Feng; Ma, Yanling; Zhang, Ying-Tao


    We investigate valley-dependent transport through a graphene sheet modulated by both the substrate strain and the fringe field of two parallel ferromagnetic metal (FM) stripes. When the magnetizations of the two FM stripes are switched from the parallel to the antiparallel alignment, the total conductance, valley polarization and valley conductance excess change greatly over a wide range of Fermi energy, which results from the dependence of the valley-related transmission suppression on the polarity configuration of inhomogeneous magnetic fields. Thus the proposed structure exhibits the significant features of a valley-filtering switch and a magnetoresistance device.

  8. A valley-filtering switch based on strained graphene

    International Nuclear Information System (INIS)

    Zhai Feng; Ma Yanling; Zhang Yingtao


    We investigate valley-dependent transport through a graphene sheet modulated by both the substrate strain and the fringe field of two parallel ferromagnetic metal (FM) stripes. When the magnetizations of the two FM stripes are switched from the parallel to the antiparallel alignment, the total conductance, valley polarization and valley conductance excess change greatly over a wide range of Fermi energy, which results from the dependence of the valley-related transmission suppression on the polarity configuration of inhomogeneous magnetic fields. Thus the proposed structure exhibits the significant features of a valley-filtering switch and a magnetoresistance device. (paper)

  9. Strain mapping near a triple junction in strained Ni-based alloy using EBSD and biaxial nanogauges

    Energy Technology Data Exchange (ETDEWEB)

    Clair, A. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France); Foucault, M.; Calonne, O. [Areva ANP, Centre Technique Departement Corrosion-Chimie, 30 Bd de l' industrie, BP 181, 71205 Le Creusot (France); Lacroute, Y.; Markey, L.; Salazar, M.; Vignal, V. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France); Finot, E., E-mail: [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France)


    Research highlights: > Surface strains measured using nanogauge were compared to the texture obtained by EBSD. > Statistics of the principal strain discern the grains according to the Schmid factor. > Strain hotspots were localized near a triple junction of alloy 600 under tensile loading. > Asymetrical profile of the GB strains is a criterion for surface cracking initiation. - Abstract: A key element for analyzing the crack initiation in strained polycrystalline alloys is the local quantification of the surface strain distribution according to the grain texture. Using electron backscattered diffraction, the local microstructure was determined to both localize a triple junction and deduce the local Schmid factors. Kernel average misorientation (KAM) was also used to map the areas of defect concentration. The maximum principal strain and the in-plane shear strain were quantified using the biaxial nanogauge. Distortions of the array of nanodots used as spot markers were analyzed near the triple junction. The crystallographic orientation and the surface strain were then investigated both statistically for each grain and locally at the grain boundaries. The superimposition of microstructure and strain maps allows the high strain gradient (reaching 3-fold the applied strain) to be localized at preferential grain boundaries near the triple junction. The Schmid factors and the KAM were compared to the maximum principal strain and the in-plane shear strain respectively. The polycrystalline deformation was attributable first to the rotation of some grains, followed by the elongation of all grains along their preferential activated slip systems.

  10. Out-of-plane strain effect on silicon-based flexible FinFETs

    KAUST Repository

    Ghoneim, Mohamed T.


    Summary form only given. We report out-of-plane strain effect on silicon based flexible FinFET, with sub 20 nm wide fins and hafnium silicate based high-κ gate dielectric. Since ultra-thin inorganic solid state substrates become flexible with reduced thickness, flexing induced strain does not enhance performance. However, detrimental effects arise as the devices are subject to various out-of-plane stresses (compressive and tensile) along the channel length.

  11. Out-of-plane strain effect on silicon-based flexible FinFETs

    KAUST Repository

    Ghoneim, Mohamed T.; Alfaraj, Nasir; Sevilla, Galo T.; Fahad, Hossain M.; Hussain, Muhammad Mustafa


    Summary form only given. We report out-of-plane strain effect on silicon based flexible FinFET, with sub 20 nm wide fins and hafnium silicate based high-κ gate dielectric. Since ultra-thin inorganic solid state substrates become flexible with reduced thickness, flexing induced strain does not enhance performance. However, detrimental effects arise as the devices are subject to various out-of-plane stresses (compressive and tensile) along the channel length.


    Ostankova, Yu V; Semenov, A V; Stoyanova, N A; Tokarevich, N K; Lyubimova, N E; Petrova, O A; Ananina, Yu V; Petrov, E M


    Comparative typing of Leptospira spp. strain collection based on analysis of 16S RNA fragment. 2 pairs of primers were used for PCR, that jointly flank 1423b.p. sized fragment. Sequences of Leptospira spp. strain 16S rRNA, presented in the international database, were used for phylogenetic analysis. A high similarity, including interspecies, of the 16S fragment in Leptospira spp. strains was shown independently of the source, serovar and serogroup. Heterogeneity of the primary matrix, spontaneous mutations of hotspots and erroneous nucleotide couplings, characteristic for 16S sequence of pathogenic Leptospira spp. strains, are discussed. Molecular-genetic characteristic of certain reference Leptospira spp. strains by 16S sequence is obtained. Results of the studies give evidence on expedience of introduction into clinical practice of identification of Leptospira spp. by 16S sequence directly from the clinical material, that would allow to significantly reduce identification time, dismiss complex type-specific sera and other labor-intensive methods.

  13. Different commercial yeast strains affecting the volatile and sensory profile of cava base wine. (United States)

    Torrens, Jordi; Urpí, Pilar; Riu-Aumatell, Montserrat; Vichi, Stefania; López-Tamames, Elvira; Buxaderas, Susana


    36 semi-industrial fermentations were carried out with 6 different yeast strains in order to assess differences in the wines' chemical and volatile profile. Two of the tested strains (Y3 and Y6) showed the fastest fermentation rates throughout 3 harvests and on 2 grape varieties. The wines fermented by three of the tested strains (Y5, Y3 and Y4) stand out for their high amounts of esters and possessed the highest fruity character. Wines from strains producing low amounts of esters and high concentrations of medium chain fatty acids, higher alcohols and six-carbon alcohols were the least appreciated at the sensory analysis. The data obtained in the present study show how the yeast strain quantitatively affects the final chemical and volatile composition of cava base wines and have repercussions on their sensory profile, independently of must variety and harvest year.

  14. The Formation and Evolution of Shear Bands in Plane Strain Compressed Nickel-Base Superalloy

    Directory of Open Access Journals (Sweden)

    Bin Tang


    Full Text Available The formation and evolution of shear bands in Inconel 718 nickel-base superalloy under plane strain compression was investigated in the present work. It is found that the propagation of shear bands under plane strain compression is more intense in comparison with conventional uniaxial compression. The morphology of shear bands was identified to generally fall into two categories: in “S” shape at severe conditions (low temperatures and high strain rates and “X” shape at mild conditions (high temperatures and low strain rates. However, uniform deformation at the mesoscale without shear bands was also obtained by compressing at 1050 °C/0.001 s−1. By using the finite element method (FEM, the formation mechanism of the shear bands in the present study was explored for the special deformation mode of plane strain compression. Furthermore, the effect of processing parameters, i.e., strain rate and temperature, on the morphology and evolution of shear bands was discussed following a phenomenological approach. The plane strain compression attempt in the present work yields important information for processing parameters optimization and failure prediction under plane strain loading conditions of the Inconel 718 superalloy.

  15. CIVAC CV-01 type pressure gage for middle vacuum pumps

    International Nuclear Information System (INIS)

    Olaru, Grigore; Aculai, Agustin


    The digital display pressure gage CIVAC CV-01 measures absolute pressures in vacuum range of 10 2 - 10 -3 mbar in any installation or equipment generating or using low pressures. It uses a transducer type PIRANI, model TR-02. It is a portable device, easy to exploit and handle. It is applied in research, chemistry, metallurgical industry, mechanical engineering. The system of coupling the transducer to the enclosure where the pressure is to be measured is of type ISO-PNEUROP with flange, collar and adjusting ring with a DN 25 ring gasket. The technical and functional features are: - Measuring error: ± 35% of real conventional value ; - Response time: 20 ms; - Number of measuring points: 1; - Output signal: 0 - 10 V d.c.; - Repeatability error: 5%; - Max weight: 1,600 Kg; Size: 91 x 117 x 187 mm. (authors)

  16. Operation of a nuclear test gage at low multiplications

    International Nuclear Information System (INIS)

    Baumann, N.P.


    The Nuclear Test Gage (NTG) at the Savannah River Plant is a subcritical multiplying facility (low k) with H 2 O moderator and 2.54-cm-diameter fuel slugs of 5 wt percent 235 U in aluminum alloy at a 4.285-cm triangular pitch. The core of the facility is 61-cm long with a normal diameter of 27 cm. The NTG is used for quality control of reactor components, such as 235 U-Al fuel tubes, Li--Al target tubes, control and safety rods, and miscellaneous special irradiation elements. A component is tested by passing it through an axial test port 11.63 cm in diameter. The ion chamber response from the resultant change in neutron source multiplication is then compared with corresponding responses from known standards

  17. Soil moisture determination with Tesla NZK 203 neutron gage

    International Nuclear Information System (INIS)

    Hally, J.


    Soil moisture was measured using the NZK 203 neutron probe manufactured by Tesla Premysleni. The individual measuring sites were spaced at a distance of 100 m. The NZK 203 set consists of a NPK 202 moisture gage and a NSK 301 scintillation detector and features the following specifications: moisture density measuring range 20 to 500 kg/m 3 , 241 Am-Be fast neutron source having a neutron flux of 7.5x10 4 n.sec -1 +-10%, operating temperature -10 to +45 degC. The measured counting rate was primarily affected by the statistical fluctuation of ionizing radiation and by instrument instability. In order that these effects should be limited each measurement was repeated 10 times with the optimum measurement time at an interval of 20 to 100 sec. The NZK 203 Tesla set was proven to be suitable for rapid and reproducible determination of moisture profiles. (J.P.)

  18. Fatigue Life Prediction of High Modulus Asphalt Concrete Based on the Local Stress-Strain Method

    Directory of Open Access Journals (Sweden)

    Mulian Zheng


    Full Text Available Previously published studies have proposed fatigue life prediction models for dense graded asphalt pavement based on flexural fatigue test. This study focused on the fatigue life prediction of High Modulus Asphalt Concrete (HMAC pavement using the local strain-stress method and direct tension fatigue test. First, the direct tension fatigue test at various strain levels was conducted on HMAC prism samples cut from plate specimens. Afterwards, their true stress-strain loop curves were obtained and modified to develop the strain-fatigue life equation. Then the nominal strain of HMAC course determined using finite element method was converted into local strain using the Neuber method. Finally, based on the established fatigue equation and converted local strain, a method to predict the pavement fatigue crack initiation life was proposed and the fatigue life of a typical HMAC overlay pavement which runs a risk of bottom-up cracking was predicted and validated. Results show that the proposed method was able to produce satisfactory crack initiation life.

  19. Geoscience Workforce Development at UNAVCO: Leveraging the NSF GAGE Facility (United States)

    Morris, A. R.; Charlevoix, D. J.; Miller, M.


    Global economic development demands that the United States remain competitive in the STEM fields, and developing a forward-looking and well-trained geoscience workforce is imperative. According to the Bureau of Labor Statistics, the geosciences will experience a growth of 19% by 2016. Fifty percent of the current geoscience workforce is within 10-15 years of retirement, and as a result, the U.S. is facing a gap between the supply of prepared geoscientists and the demand for well-trained labor. Barring aggressive intervention, the imbalance in the geoscience workforce will continue to grow, leaving the increased demand unmet. UNAVCO, Inc. is well situated to prepare undergraduate students for placement in geoscience technical positions and advanced graduate study. UNAVCO is a university-governed consortium facilitating research and education in the geosciences and in addition UNAVCO manages the NSF Geodesy Advancing Geosciences and EarthScope (GAGE) facility. The GAGE facility supports many facets of geoscience research including instrumentation and infrastructure, data analysis, cyberinfrastructure, and broader impacts. UNAVCO supports the Research Experiences in the Solid Earth Sciences for Students (RESESS), an NSF-funded multiyear geoscience research internship, community support, and professional development program. The primary goal of the RESESS program is to increase the number of historically underrepresented students entering graduate school in the geosciences. RESESS has met with high success in the first 9 years of the program, as more than 75% of RESESS alumni are currently in Master's and PhD programs across the U.S. Building upon the successes of RESESS, UNAVCO is launching a comprehensive workforce development program that will network underrepresented groups in the geosciences to research and opportunities throughout the geosciences. This presentation will focus on the successes of the RESESS program and plans to expand on this success with broader

  20. Design of cross-sensitive temperature and strain sensor based on sampled fiber grating

    Directory of Open Access Journals (Sweden)

    Zhang Xiaohang


    Full Text Available In this paper,a cross-sensitive temperature and strain sensor based on sampled fiber grating is designed.Its temperature measurement range is -50-200℃,and the strain measurement rangeis 0-2 000 με.The characteristics of the sensor are obtained using simulation method.Utilizing SPSS software,we found the dual-parameter matrix equations of measurement of temperature and strain,and calibrated the four sensing coefficients of the matrix equations.

  1. Prediction of material creep behaviour for strain based life assessment applications

    Energy Technology Data Exchange (ETDEWEB)

    Rantala, J.H.; Hurst, R.C. [EC JRC IAM, Petten (Netherlands); Bregani, F. [ENEL, Milan (Italy)


    In this work the idea of using constant load uniaxial creep test results instead of constant stress results for developing a CDM creep model for the P92 material is demonstrated. Due to limited availability of creep test results this work is based on incomplete test data and a general stress rupture line. In spite of these limitations a material creep model was developed for use in a FE analysis. Using P91 material as an example, a method is proposed to account for differences in strain evolution as a function of stress which normally manifests itself as lower strain values at low stresses in a normalised time-strain plot. This allows the CDM model to be used both in FE analysis and in strain-based life assessment engineering calculations. (orig.) 3 refs.

  2. Prediction of material creep behaviour for strain based life assessment applications

    Energy Technology Data Exchange (ETDEWEB)

    Rantala, J H; Hurst, R C [EC JRC IAM, Petten (Netherlands); Bregani, F [ENEL, Milan (Italy)


    In this work the idea of using constant load uniaxial creep test results instead of constant stress results for developing a CDM creep model for the P92 material is demonstrated. Due to limited availability of creep test results this work is based on incomplete test data and a general stress rupture line. In spite of these limitations a material creep model was developed for use in a FE analysis. Using P91 material as an example, a method is proposed to account for differences in strain evolution as a function of stress which normally manifests itself as lower strain values at low stresses in a normalised time-strain plot. This allows the CDM model to be used both in FE analysis and in strain-based life assessment engineering calculations. (orig.) 3 refs.

  3. Preparation and Property Research of Strain Sensor Based on PDMS and Silver Nanomaterials

    Directory of Open Access Journals (Sweden)

    Lihua Liu


    Full Text Available Based on the advantages and broad applications of stretchable strain sensors, this study reports a simple method to fabricate a highly sensitive strain sensor with Ag nanomaterials-polydimethylsiloxane (AgNMs-PDMS to create a synergic conductive network and a sandwich-structure. Three Ag nanomaterial samples were synthesized by controlling the concentrations of the FeCl3 solution and reaction time via the heat polyols thermal method. The AgNMs network’s elastomer nanocomposite-based strain sensors show strong piezoresistivity with a high gauge factor of 547.8 and stretchability from 0.81% to 7.26%. The application of our high-performance strain sensors was demonstrated by the inducting finger of the motion detection. These highly sensitive sensors conform to the current trends of flexible electronics and have prospects for broad application.

  4. Prion strain discrimination based on rapid in vivo amplification and analysis by the cell panel assay.

    Directory of Open Access Journals (Sweden)

    Yervand Eduard Karapetyan

    Full Text Available Prion strain identification has been hitherto achieved using time-consuming incubation time determinations in one or more mouse lines and elaborate neuropathological assessment. In the present work, we make a detailed study of the properties of PrP-overproducing Tga20 mice. We show that in these mice the four prion strains examined are rapidly and faithfully amplified and can subsequently be discriminated by a cell-based procedure, the Cell Panel Assay.

  5. Assessment of creep-fatigue damage using the UK strain based procedure

    International Nuclear Information System (INIS)

    Bate, S.K.


    The UK strain based procedures have been developed for the evaluation of damage in structures, arising from fatigue cycles and creep processes. The fatigue damage is assessed on the basis of modelling crack growth from about one grain depth to an allowable limit which represents an engineering definition of crack formation. Creep damage is based up on the exhaustion of available ductility by creep strain accumulation. The procedures are applicable only when level A and B service conditions apply, as defined in RCC-MR or ASME Code Case N47. The procedures require the components of strain to be evaluated separately, thus they may be used with either full inelastic analysis or simplified methods. To support the development of the UK strain based creep-fatigue procedures an experimental program was undertaken by NNC to study creep-fatigue interaction of structures operating at high temperature. These tests, collectively known as the SALTBATH tests considered solid cylinder and tube-plate specimens, manufactured from Type 316 stainless steel. These specimens were subjected to thermal cycles between 250 deg. C and 600 deg. C. In all the cases the thermal cycle produces tensile residual stresses during dwells at 600 deg. C. One of the tube-plate specimens was used as a benchmark for validating the strain based creep fatigue procedures and subsequently as part of a CEC co-operative study. This benchmark work is described in this paper. A thermal and inelastic stress analysis was carried out using the finite element code ABAQUS. The inelastic behaviour of the material was described using the ORNL constitutive equations. A creep fatigue assessment using the strain based procedures has been compared with an assessment using the RCC-MR inelastic rules. The analyses indicated that both the UK strain based procedures and the RCC-MR rules were conservative, but the conservatism was greater for the RCC-MR rules. (author). 8 refs, 8 figs, 4 tabs

  6. Pipeline Bending Strain Measurement and Compensation Technology Based on Wavelet Neural Network

    Directory of Open Access Journals (Sweden)

    Rui Li


    Full Text Available The bending strain of long distance oil and gas pipelines may lead to instability of the pipeline and failure of materials, which seriously deteriorates the transportation security of oil and gas. To locate the position of the bending strain for maintenance, an Inertial Measurement Unit (IMU is usually adopted in a Pipeline Inspection Gauge (PIG. The attitude data of the IMU is usually acquired to calculate the bending strain in the pipe. However, because of the vibrations in the pipeline and other system noises, the resulting bending strain calculations may be incorrect. To improve the measurement precision, a method, based on wavelet neural network, was proposed. To test the proposed method experimentally, a PIG with the proposed method is used to detect a straight pipeline. It can be obtained that the proposed method has a better repeatability and convergence than the original method. Furthermore, the new method is more accurate than the original method and the accuracy of bending strain is raised by about 23% compared to original method. This paper provides a novel method for precisely inspecting bending strain of long distance oil and gas pipelines and lays a foundation for improving the precision of inspection of bending strain of long distance oil and gas pipelines.

  7. [Determination of genetic bases of auxotrophy in Yersinia pestis ssp. caucasica strains]. (United States)

    Odinokov, G N; Eroshenko, G A; Kukleva, L M; Shavina, N Iu; Krasnov, Ia M; Kutyrev, V V


    Based on the results of computer analysis of nucleotide sequences in strains Yersinia pestis and Y. pseudotuberculosis recorded in the files of NCBI GenBank database, differences between genes argA, aroG, aroF, thiH, and thiG of strain Pestoides F (subspecies caucasica) were found, compared to other strains of plaque agent and pseudotuberculosis microbe. Using PCR with calculated primers and the method of sequence analysis, the structure of variable regions of these genes was studied in 96 natural Y. pestis and Y. pseudotuberculosis strains. It was shown that all examined strains of subspecies caucasica, unlike strains of plague-causing agent of other subspecies and pseudotubercolosis microbe, had identical mutations in genes argA (integration of the insertion sequence IS100), aroG (insertion of ten nucleotides), aroF (inserion of IS100), thiH (insertion of nucleotide T), and thiG (deletion of 13 nucleotides). These mutations are the reason for the absence in strains belonging to this subspecies of the ability to synthesize arginine, phenylalanine, tyrosine, and vitamin B1 (thiamine), and cause their auxotrophy for these growth factors.

  8. Strain-based control of crystal anisotropy for perovskite oxides on semiconductor-based material (United States)

    McKee, Rodney Allen; Walker, Frederick Joseph


    A crystalline structure and a semiconductor device includes a substrate of a semiconductor-based material and a thin film of an anisotropic crystalline material epitaxially arranged upon the surface of the substrate so that the thin film couples to the underlying substrate and so that the geometries of substantially all of the unit cells of the thin film are arranged in a predisposed orientation relative to the substrate surface. The predisposition of the geometries of the unit cells of the thin film is responsible for a predisposed orientation of a directional-dependent quality, such as the dipole moment, of the unit cells. The predisposed orientation of the unit cell geometries are influenced by either a stressed or strained condition of the lattice at the interface between the thin film material and the substrate surface.

  9. Development of a Brillouin scattering based distributed fibre optic strain sensor (United States)

    Brown, Anthony Wayne


    The parameters of the Brillouin spectrum of an optical fibre depend upon the strain and temperature conditions of the fibre. As a result, fibre optic distributed sensors based on Brillouin scattering can measure strain and temperature in arbitrary regions of a sensing fibre. In the past, such sensors have often been demonstrated under laboratory conditions, demonstrating the principle of operation. Although some field tests of temperature sensing have been reported, the actual deployment of such sensors in the field for strain measurements has been limited by poor spatial resolution (typically 1 m or more) and poor strain accuracy (+/-100 muepsilon). Also, cross-sensitivity of the Brillouin spectrum to temperature further reduces the accuracy of strain measurement while long acquisition times hinders field use. The high level of user knowledge and lack of automation required to operate the equipment is another limiting factor of the only commercially available unit. The potential benefits of distributed measurements are great for instrumentation of civil structures provided that the above limitations are overcome. However, before this system is used with confidence by practitioners, it is essential that it can be effectively operated in field conditions. In light of this, the fibre optics group at the University of New Brunswick has been developing an automated system for field measurement of strain in civil structures, particularly in reinforced concrete. The development of the sensing system hardware and software was the main focus of this thesis. This has been made possible, in part, by observation of the Brillouin spectrum for the case of using very short light pulses (performance to measure strain to an accuracy of 10 muepsilon; and allow the simultaneous measurement of strain and temperature to an accuracy of 204 muepsilon and 3°C are presented. Finally, the results of field measurement of strain on a concrete structure are presented.

  10. The effects of strain rate and carbon concentration on the dynamic strain aging of cold rolled Ni-based alloy in high temperature water

    International Nuclear Information System (INIS)

    Kuang, Wenjun; Was, Gary S.


    Graphical abstract: The stress amplitude of serrations first increases with decreasing strain rate and then gradually saturates. The matrix carbon concentration affects the stress amplitude and the tendency to saturation. - Abstract: The effect of strain rate on dynamic strain aging of cold-rolled Ni-based alloy was investigated. With decreasing strain rate, the stress amplitude of serrations first increased and then saturated. Compared with the solution-annealed condition, the thermally-treated condition produced smaller stress amplitudes that saturated at a lower strain rate. Observations are consistent with a mechanism in which the locking strength of solute atmospheres first increases with increasing solute atom arrival at dislocations and gradually saturates as solute reaches a critical level

  11. Comparative Analysis of two Helicobacter pylori Strains using Genomics and Mass Spectrometry-Based Proteomics

    Directory of Open Access Journals (Sweden)

    Roger Karlsson


    Full Text Available Helicobacter pylori, a gastroenteric pathogen believed to have co-evolved with humans over 100,000 years, shows significant genetic variability. This motivates the study of different H. pylori strains and the diseases they cause in order to identify determinants for disease evolution. In this study, we used proteomics tools to compare two H. pylori strains. Nic25_A was isolated in Nicaragua from a patient with intestinal metaplasia, and P12 was isolated in Europe from a patient with duodenal ulcers. Differences in the abundance of surface proteins between the two strains were determined with two mass spectrometry-based methods, label-free quantification (MaxQuant or the use of tandem mass tags (TMT. Each approach used a lipid-based protein immobilization (LPI™ technique to enrich peptides of surface proteins. Using the MaxQuant software, we found 52 proteins that differed significantly in abundance between the two strains (up- or downregulated by a factor of 1.5; with TMT, we found 18 proteins that differed in abundance between the strains. Strain P12 had a higher abundance of proteins encoded by the cag pathogenicity island, while levels of the acid response regulator ArsR and its regulatory targets (KatA, AmiE, and proteins involved in urease production were higher in strain Nic25_A. Our results show that differences in protein abundance between H. pylori strains can be detected with proteomic approaches; this could have important implications for the study of disease progression.

  12. Fabrication of strain gauge based sensors for tactile skins (United States)

    Baptist, Joshua R.; Zhang, Ruoshi; Wei, Danming; Saadatzi, Mohammad Nasser; Popa, Dan O.


    Fabricating cost effective, reliable and functional sensors for electronic skins has been a challenging undertaking for the last several decades. Application of such skins include haptic interfaces, robotic manipulation, and physical human-robot interaction. Much of our recent work has focused on producing compliant sensors that can be easily formed around objects to sense normal, tension, or shear forces. Our past designs have involved the use of flexible sensors and interconnects fabricated on Kapton substrates, and piezoresistive inks that are 3D printed using Electro Hydro Dynamic (EHD) jetting onto interdigitated electrode (IDE) structures. However, EHD print heads require a specialized nozzle and the application of a high-voltage electric field; for which, tuning process parameters can be difficult based on the choice of inks and substrates. Therefore, in this paper we explore sensor fabrication techniques using a novel wet lift-off photolithographic technique for patterning the base polymer piezoresistive material, specifically Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) or PEDOT:PSS. Fabricated sensors are electrically and thermally characterized, and temperaturecompensated designs are proposed and validated. Packaging techniques for sensors in polymer encapsulants are proposed and demonstrated to produce a tactile interface device for a robot.

  13. Standard Test Method for Measuring Heat Flux Using Flush-Mounted Insert Temperature-Gradient Gages

    CERN Document Server

    American Society for Testing and Materials. Philadelphia


    1.1 This test method describes the measurement of the net heat flux normal to a surface using gages inserted flush with the surface. The geometry is the same as heat-flux gages covered by Test Method E 511, but the measurement principle is different. The gages covered by this standard all use a measurement of the temperature gradient normal to the surface to determine the heat that is exchanged to or from the surface. Although in a majority of cases the net heat flux is to the surface, the gages operate by the same principles for heat transfer in either direction. 1.2 This general test method is quite broad in its field of application, size and construction. Two different gage types that are commercially available are described in detail in later sections as examples. A summary of common heat-flux gages is given by Diller (1). Applications include both radiation and convection heat transfer. The gages used for aerospace applications are generally small (0.155 to 1.27 cm diameter), have a fast time response ...

  14. Effect of strain on voltage-controlled magnetism in BiFeO₃-based heterostructures. (United States)

    Wang, J J; Hu, J M; Yang, T N; Feng, M; Zhang, J X; Chen, L Q; Nan, C W


    Voltage-modulated magnetism in magnetic/BiFeO3 heterostructures can be driven by a combination of the intrinsic ferroelectric-antiferromagnetic coupling in BiFeO3 and the antiferromagnetic-ferromagnetic exchange interaction across the heterointerface. However, ferroelectric BiFeO3 film is also ferroelastic, thus it is possible to generate voltage-induced strain in BiFeO3 that could be applied onto the magnetic layer across the heterointerface and modulate magnetism through magnetoelastic coupling. Here, we investigated, using phase-field simulations, the role of strain in voltage-controlled magnetism for these BiFeO3-based heterostructures. It is predicted, under certain condition, coexistence of strain and exchange interaction will result in a pure voltage-driven 180° magnetization reversal in BiFeO3-based heterostructures.

  15. Effect of strain on voltage-controlled magnetism in BiFeO3-based heterostructures (United States)

    Wang, J. J.; Hu, J. M.; Yang, T. N.; Feng, M.; Zhang, J. X.; Chen, L. Q.; Nan, C. W.


    Voltage-modulated magnetism in magnetic/BiFeO3 heterostructures can be driven by a combination of the intrinsic ferroelectric-antiferromagnetic coupling in BiFeO3 and the antiferromagnetic-ferromagnetic exchange interaction across the heterointerface. However, ferroelectric BiFeO3 film is also ferroelastic, thus it is possible to generate voltage-induced strain in BiFeO3 that could be applied onto the magnetic layer across the heterointerface and modulate magnetism through magnetoelastic coupling. Here, we investigated, using phase-field simulations, the role of strain in voltage-controlled magnetism for these BiFeO3-based heterostructures. It is predicted, under certain condition, coexistence of strain and exchange interaction will result in a pure voltage-driven 180° magnetization reversal in BiFeO3-based heterostructures. PMID:24686503

  16. Improving the durability of the optical fiber sensor based on strain transfer analysis (United States)

    Wang, Huaping; Jiang, Lizhong; Xiang, Ping


    To realize the reliable and long-term strain detection, the durability of optical fiber sensors has attracted more and more attention. The packaging technique has been considered as an effective method, which can enhance the survival ratios of optical fiber sensors to resist the harsh construction and service environment in civil engineering. To monitor the internal strain of structures, the embedded installation is adopted. Due to the different material properties between host material and the protective layer, the monitored structure embedded with sensors can be regarded as a typical model containing inclusions. Interfacial characteristic between the sensor and host material exists obviously, and the contacted interface is prone to debonding failure induced by the large interfacial shear stress. To recognize the local interfacial debonding damage and extend the effective life cycle of the embedded sensor, strain transfer analysis of a general three-layered sensing model is conducted to investigate the failure mechanism. The perturbation of the embedded sensor on the local strain field of host material is discussed. Based on the theoretical analysis, the distribution of the interfacial shear stress along the sensing length is characterized and adopted for the diagnosis of local interfacial debonding, and the sensitive parameters influencing the interfacial shear stress are also investigated. The research in this paper explores the interfacial debonding failure mechanism of embedded sensors based on the strain transfer analysis and provides theoretical basis for enhancing the interfacial bonding properties and improving the durability of embedded optical fiber sensors.

  17. United States Geological Survey discharge data from five example gages on intermittent streams (United States)

    U.S. Environmental Protection Agency — The data are mean daily discharge data at United States Geological Survey gages. Once column provides the date (mm/dd/yyyy) and the other column provides the mean...

  18. Portable neutron moisture gage for the moisture determination of structure parts

    International Nuclear Information System (INIS)

    Harnisch, M.


    For determining the moisture of structure parts during building or before repairing a portable neutron moisture gage consisting of a neutron probe and pulse analyzer has been developed. The measuring process, calibration, and prerequisites of application are briefly discussed

  19. Strain-Based Design Methodology of Large Diameter Grade X80 Linepipe

    Energy Technology Data Exchange (ETDEWEB)

    Lower, Mark D. [ORNL


    Continuous growth in energy demand is driving oil and natural gas production to areas that are often located far from major markets where the terrain is prone to earthquakes, landslides, and other types of ground motion. Transmission pipelines that cross this type of terrain can experience large longitudinal strains and plastic circumferential elongation as the pipeline experiences alignment changes resulting from differential ground movement. Such displacements can potentially impact pipeline safety by adversely affecting structural capacity and leak tight integrity of the linepipe steel. Planning for new long-distance transmission pipelines usually involves consideration of higher strength linepipe steels because their use allows pipeline operators to reduce the overall cost of pipeline construction and increase pipeline throughput by increasing the operating pressure. The design trend for new pipelines in areas prone to ground movement has evolved over the last 10 years from a stress-based design approach to a strain-based design (SBD) approach to further realize the cost benefits from using higher strength linepipe steels. This report presents an overview of SBD for pipelines subjected to large longitudinal strain and high internal pressure with emphasis on the tensile strain capacity of high-strength microalloyed linepipe steel. The technical basis for this report involved engineering analysis and examination of the mechanical behavior of Grade X80 linepipe steel in both the longitudinal and circumferential directions. Testing was conducted to assess effects on material processing including as-rolled, expanded, and heat treatment processing intended to simulate coating application. Elastic-plastic and low-cycle fatigue analyses were also performed with varying internal pressures. Proposed SBD models discussed in this report are based on classical plasticity theory and account for material anisotropy, triaxial strain, and microstructural damage effects

  20. Vibration based structural health monitoring in fibre reinforced composites employing the modal strain energy method

    NARCIS (Netherlands)

    Loendersloot, Richard; Ooijevaar, T.H.; Warnet, Laurent; Akkerman, Remko; de Boer, Andries; Meguid, S.A.; Gomes, J.F.S.


    The feasibility of a vibration based damage identification method is investigated. The Modal Strain Energy method is applied to a T–beam structure. The dynamic response of an intact structure and a damaged, delaminated structure is analysed employing a commercially available Finite Element package.

  1. Prediction of slope stability based on numerical modeling of stress–strain state of rocks (United States)

    Kozhogulov Nifadyev, KCh, VI; Usmanov, SF


    The paper presents the developed technique for the estimation of rock mass stability based on the finite element modeling of stress–strain state of rocks. The modeling results on the pit wall landslide as a flow of particles along a sloped surface are described.

  2. Strain-based finite elements for the analysis of cylinders with holes and normally intersecting cylinders

    International Nuclear Information System (INIS)

    Sabir, A.B.


    A finite element solution to the problems of stress distribution for cylindrical shells with circular and elliptical holes and also for normally intersecting thin elastic cylindrical shells is given. Quadrilateral and triangular curved finite elements are used in the analysis. The elements are of a new class, based on simple independent generalised strain functions insofar as this is allowed by the compatibility equations. The elements also satisfy exactly the requirements of strain-free-rigid body displacements and uses only the external 'geometrical' nodal degrees of freedom to avoid the difficulties associated with unnecessary internal degrees of freedom. We first develop strain based quadrilateral and triangular elements and apply them to the solution of the problem of stress concentrations in the neighbourhood of small and large circular and elliptical holes when the cylinders are subjected to a uniform axial tension. These results are compared with analytical solutions based on shallow shell approximations and show that the use of these strain based elements obviates the need for using an inordinately large number of elements. Normally intersecting cylinders are common configurations in structural components for nuclear reactor systems and design information for such configurations are generally lacking. The opportunity is taken in the present paper to provide a finite element solution to this problem. A method of substructing will be introduced to enable a solution to the large number of non banded set of simultaneous equations encountered. (orig./HP)

  3. Standard test method for determining residual stresses by the hole-drilling strain-gage method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia


    1.1 Residual Stress Determination: 1.1.1 This test method specifies a hole-drilling procedure for determining residual stress profiles near the surface of an isotropic linearly elastic material. The test method is applicable to residual stress profile determinations where in-plane stress gradients are small. The stresses may remain approximately constant with depth (“uniform” stresses) or they may vary significantly with depth (“non-uniform” stresses). The measured workpiece may be “thin” with thickness much less than the diameter of the drilled hole or “thick” with thickness much greater than the diameter of the drilled hole. Only uniform stress measurements are specified for thin workpieces, while both uniform and non-uniform stress measurements are specified for thick workpieces. 1.2 Stress Measurement Range: 1.2.1 The hole-drilling method can identify in-plane residual stresses near the measured surface of the workpiece material. The method gives localized measurements that indicate the...

  4. Development of Displacement Gages Exposed to Solid Rocket Motor Internal Environments (United States)

    Bolton, D. E.; Cook, D. J.


    The Space Shuttle Reusable Solid Rocket Motor (RSRM) has three non-vented segment-to-segment case field joints. These joints use an interference fit J-joint that is bonded at assembly with a Pressure Sensitive Adhesive (PSA) inboard of redundant O-ring seals. Full-scale motor and sub-scale test article experience has shown that the ability to preclude gas leakage past the J-joint is a function of PSA type, joint moisture from pre-assembly humidity exposure, and the magnitude of joint displacement during motor operation. To more accurately determine the axial displacements at the J-joints, two thermally durable displacement gages (one mechanical and one electrical) were designed and developed. The mechanical displacement gage concept was generated first as a non-electrical, self-contained gage to capture the maximum magnitude of the J-joint motion. When it became feasible, the electrical displacement gage concept was generated second as a real-time linear displacement gage. Both of these gages were refined in development testing that included hot internal solid rocket motor environments and simulated vibration environments. As a result of this gage development effort, joint motions have been measured in static fired RSRM J-joints where intentional venting was produced (Flight Support Motor #8, FSM-8) and nominal non-vented behavior occurred (FSM-9 and FSM-10). This data gives new insight into the nominal characteristics of the three case J-joint positions (forward, center and aft) and characteristics of some case J-joints that became vented during motor operation. The data supports previous structural model predictions. These gages will also be useful in evaluating J-joint motion differences in a five-segment Space Shuttle solid rocket motor.

  5. Design of Gages for Direct Skin Friction Measurements in Complex Turbulent Flows with Shock Impingement Compensation (United States)


    100 kW/m2 for 0.1 s. Along with the material change, an oil leak problem required a geometric change. Initially, we considered TIG welding or...shear and moment, is addressed through the design, development, and testing of the CF1 and CF2 gages. Chapter 3 presents the evolutionary process ...a shock. Chapter 4 examines the performance of each gage to the nominal load conditions. Through this process , objective 2 is met. The best

  6. Genetic characterization of Italian field strains of Schmallenberg virus based on N and NSs genes. (United States)

    Izzo, Francesca; Cosseddu, Gian Mario; Polci, Andrea; Iapaolo, Federica; Pinoni, Chiara; Capobianco Dondona, Andrea; Valleriani, Fabrizia; Monaco, Federica


    Following its first identification in Germany in 2011, the Schmallenberg virus (SBV) has rapidly spread to many other European countries. Despite the wide dissemination, the molecular characterization of the circulating strains is limited to German, Belgian, Dutch, and Swiss viruses. To fill this gap, partial genetic characterization of 15 Italian field strains was performed, based on S segment genes. Samples were collected in 2012 in two different regions where outbreaks occurred during distinct epidemic seasons. The comparative sequence analysis demonstrated a high molecular stability of the circulating viruses; nevertheless, we identified several variants of the N and NSs proteins not described in other SBV isolates circulating in Europe.

  7. A Comparative Study Between Strain And Stress Based Forming Limit Analysis By Applying Several Phenomenological Yield Criteria

    International Nuclear Information System (INIS)

    Butuc, Marilena C.; Vincze, Gabriela T.; Gracio, Jose J.; Barata da Rocha, A.


    The present work aims at analyzing a comparative study between the strain-based forming limit criterion (FLD) and the stress-based forming limit criterion (FLSD), under linear and complex strain paths. The selected material is an AA5182-0 aluminium alloy. Some relevant remarks about stress-based forming limit criterion concept are presented

  8. Analysis of structures based on a characteristic-strain model of creep

    Energy Technology Data Exchange (ETDEWEB)

    Bolton, J. [Alstom Power, Newbold Road, Rugby CV21 2NH (United Kingdom)], E-mail:


    A companion paper [Bolton J. In: A characteristic-strain model for creep, ECCC/I.Mech.E. conference on creep and fracture in high-temperature components, London, September 2005] describes a creep model based on a constant 'characteristic strain' at any temperature. The present paper discusses the application of such a model, first to simple structures and then to engineering components of general form under steady loading. A basis is proposed for identifying the stress within a structure, or within the critical part of a structure, which can be considered to govern both its overall and local deformations. The concept is similar to skeletal-point stress but is more readily applied to components of any shape. The implementation of the concept of 'structural stress' is discussed in the context of finite-element creep calculations. Consideration is given to the analysis of cracked structures, where very high strains at the crack tip must be accommodated.

  9. Analysis of structures based on a characteristic-strain model of creep

    International Nuclear Information System (INIS)

    Bolton, J.


    A companion paper [Bolton J. In: A characteristic-strain model for creep, ECCC/I.Mech.E. conference on creep and fracture in high-temperature components, London, September 2005] describes a creep model based on a constant 'characteristic strain' at any temperature. The present paper discusses the application of such a model, first to simple structures and then to engineering components of general form under steady loading. A basis is proposed for identifying the stress within a structure, or within the critical part of a structure, which can be considered to govern both its overall and local deformations. The concept is similar to skeletal-point stress but is more readily applied to components of any shape. The implementation of the concept of 'structural stress' is discussed in the context of finite-element creep calculations. Consideration is given to the analysis of cracked structures, where very high strains at the crack tip must be accommodated

  10. Up-taper-based Mach-Zehnder interferometer for temperature and strain simultaneous measurement. (United States)

    Kang, Zexin; Wen, Xiaodong; Li, Chao; Sun, Jiang; Wang, Jing; Jian, Shuisheng


    A novel all-fiber sensing configuration for simultaneous measurements of temperature and strain based on the up-taper Mach-Zehnder interferometer (MZI) with an in-line embedded fiber Bragg grating (FBG) is proposed and experimentally demonstrated. This configuration consists of two up-tapers fabricated by an excessive fusion splicing method and a short segment of inscribed FBG. Due to the different responses of the up-taper MZI and the FBG to the uniform variation of temperature and strain, the simultaneous measurement for these two variables could be achieved by real-time monitoring the transmission spectrum. For 0.01 nm wavelength resolution, a resolution of 0.311°C in temperature can be achieved, and the average strain resolution is 10.07 με.

  11. Transparent and stretchable strain sensors based on metal nanowire microgrids for human motion monitoring (United States)

    Cho, Ji Hwan; Ha, Sung-Hun; Kim, Jong-Man


    Optical transparency is increasingly considered as one of the most important characteristics required in advanced stretchable strain sensors for application in body-attachable systems. In this paper, we present an entirely solution-processed fabrication route to highly transparent and stretchable resistive strain sensors based on silver nanowire microgrids (AgNW-MGs). The AgNW-MG strain sensors are readily prepared by patterning the AgNWs on a stretchable substrate into a MG geometry via a mesh-template-assisted contact-transfer printing. The MG has a unique architecture comprising the AgNWs and can be stretched to ɛ = 35%, with high gauge factors of ˜6.9 for ɛ = 0%-30% and ˜41.1 for ɛ = 30%-35%. The sensor also shows a high optical transmittance of 77.1% ± 1.5% (at 550 nm) and stably maintains the remarkable optical performance even at high strains. In addition, the sensor responses are found to be highly reversible with negligible hysteresis and are reliable even under repetitive stretching-releasing cycles (1000 cycles at ɛ = 10%). The practicality of the AgNW-MG strain sensor is confirmed by successfully monitoring a wide range of human motions in real time after firmly laminating the device onto various body parts.

  12. Reliability Assessment for PSC Box-Girder Bridges Based on SHM Strain Measurements

    Directory of Open Access Journals (Sweden)

    Chuang Chen


    Full Text Available A reliability assessment method for prestressed concrete (PSC continuous box-girder bridges based on structural health monitoring (SHM strain measurements was proposed. First, due to the fact that measured strain was compositive and the variation periods of its components were different, a series of limit state equations under normal use limit state were given. Then, a linear fitting method was used to determine the relationship between the ambient temperature and the measured strain, which was aimed at extracting the vehicle load effect and the temperature load effect from the measured strain. Finally, according to the equivalent normalization method, the load effects unsatisfying the normal distribution by probability density function fitting were transformed, and the daily failure probabilities of monitored positions were calculated for evaluating the safety state of the girder. The results show that (1 the top plate of the box girder is more sensitive than the bottom plate to the high temperature, (2 the daily and seasonal strain variations induced by uniform temperature reveal an inconsistent tendency to the seasonal variation for mid-span cross sections, and (3 the generalized extreme value distribution is recommended for temperature gradient stress and vehicle induced stress fitting for box-girder bridges.

  13. Piezoresistive strain sensing of carbon nanotubes-based composite skin for aeronautical morphing structures (United States)

    Viscardi, Massimo; Arena, Maurizio; Barra, Giuseppina; Vertuccio, Luigi; Ciminello, Monica; Guadagno, Liberata


    Nowadays, smart composites based on different nano-scale carbon fillers, such as carbon nanotubes (CNTs), are increasingly being thought of as a more possible alternative solution to conventional smart materials, mainly for their improved electrical properties. Great attention is being given by the research community in designing highly sensitive strain sensors for more and more ambitious challenges: in such context, interest fields related to carbon nanotubes have seen extraordinary development in recent years. The authors aim to provide the most contemporary overview possible of carbon nanotube-based strain sensors for aeronautical application. A smart structure as a morphing wing needs an embedded sensing system in order to measure the actual deformation state as well as to "monitor" the structural conditions. Looking at more innovative health monitoring tools for the next generation of composite structures, a resin strain sensor has been realized. The epoxy resin was first analysed by means of a micro-tension test, estimating the electrical resistance variations as function of the load, in order to demonstrate the feasibility of the sensor. The epoxy dogbone specimen has been equipped with a standard strain gauge to quantify its strain sensitivity. The voltamperometric tests highlight a good linearity of the electrical resistance value as the load increases at least in the region of elastic deformation of the material. Such intrinsic piezoresistive performance is essentially attributable to the re-arrangement of conductive percolating network formed by MWCNT, induced by the deformation of the material due to the applied loads. The specimen has been prepared within this investigation, to demonstrate its performance for a future composite laminate typical of aerospace structures. The future carbon-fiber sensor can replace conventional metal foil strain gauges in aerospace applications. Furthermore, dynamic tests will be carried out to detect any non

  14. Magnetic attachment for implant overdentures: influence of contact relationship with the denture base on stability and bending strain. (United States)

    Yang, Tsung-Chieh; Maeda, Yoshinobu; Gonda, Tomoya; Wada, Masahiro


    This study evaluated how the contact height between the magnetic attachment and denture base influences stability and bending strain. An implant modified with strain gauges and a magnetic attachment mounted in an acrylic resin block were used to characterize systems with varying degrees or heights of contact with the abutment. Bending strain under lateral loading increased significantly as the contact height decreased. In the no contact and resilient contact groups, magnetic assemblies separated at reduced bending strain in all loading conditions. The contact height of the magnetic attachment influenced the stability and the amount of bending strain on the implant.

  15. Strain expansion-reduction approach (United States)

    Baqersad, Javad; Bharadwaj, Kedar


    Validating numerical models are one of the main aspects of engineering design. However, correlating million degrees of freedom of numerical models to the few degrees of freedom of test models is challenging. Reduction/expansion approaches have been traditionally used to match these degrees of freedom. However, the conventional reduction/expansion approaches are only limited to displacement, velocity or acceleration data. While in many cases only strain data are accessible (e.g. when a structure is monitored using strain-gages), the conventional approaches are not capable of expanding strain data. To bridge this gap, the current paper outlines a reduction/expansion technique to reduce/expand strain data. In the proposed approach, strain mode shapes of a structure are extracted using the finite element method or the digital image correlation technique. The strain mode shapes are used to generate a transformation matrix that can expand the limited set of measurement data. The proposed approach can be used to correlate experimental and analytical strain data. Furthermore, the proposed technique can be used to expand real-time operating data for structural health monitoring (SHM). In order to verify the accuracy of the approach, the proposed technique was used to expand the limited set of real-time operating data in a numerical model of a cantilever beam subjected to various types of excitations. The proposed technique was also applied to expand real-time operating data measured using a few strain gages mounted to an aluminum beam. It was shown that the proposed approach can effectively expand the strain data at limited locations to accurately predict the strain at locations where no sensors were placed.

  16. Strain-based HLA association analysis identified HLA-DRB1*09:01 associated with modern strain tuberculosis. (United States)

    Toyo-Oka, L; Mahasirimongkol, S; Yanai, H; Mushiroda, T; Wattanapokayakit, S; Wichukchinda, N; Yamada, N; Smittipat, N; Juthayothin, T; Palittapongarnpim, P; Nedsuwan, S; Kantipong, P; Takahashi, A; Kubo, M; Sawanpanyalert, P; Tokunaga, K


    Tuberculosis (TB) occurs as a result of complex interactions between the host immune system and pathogen virulence factors. Human leukocyte antigen (HLA) class II molecules play an important role in the host immune system. However, no study has assessed the association between HLA class II genes and susceptibility to TB caused by specific strains. This study investigated the possible association of HLA class II genes with TB caused by modern and ancient Mycobacterium tuberculosis (MTB). The study included 682 patients with TB and 836 control subjects who were typed for HLA-DRB1 and HLA-DQB1 alleles. MTB strains were classified using a large sequence polymorphism typing method. Association analysis was performed using common HLA alleles and haplotypes in different MTB strains. HLA association analysis of patients infected with modern MTB strains showed significant association for HLA-DRB1*09:01 (odds ratio [OR] = 1.82; P-value = 9.88 × 10 -4 ) and HLA-DQB1*03:03 alleles (OR = 1.76; P-value = 1.31 × 10 -3 ) with susceptibility to TB. Haplotype analysis confirmed that these alleles were in strong linkage disequilibrium and did not exert an interactive effect. Thus, the results of this study showed an association between HLA class II genes and susceptibility to TB caused by modern MTB strains, suggesting the importance of strain-specific analysis to determine susceptibility genes associated with TB. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Prediction of strain energy-based liquefaction resistance of sand-silt mixtures: An evolutionary approach (United States)

    Baziar, Mohammad H.; Jafarian, Yaser; Shahnazari, Habib; Movahed, Vahid; Amin Tutunchian, Mohammad


    Liquefaction is a catastrophic type of ground failure, which usually occurs in loose saturated soil deposits under earthquake excitations. A new predictive model is presented in this study to estimate the amount of strain energy density, which is required for the liquefaction triggering of sand-silt mixtures. A wide-ranging database containing the results of cyclic tests on sand-silt mixtures was first gathered from previously published studies. Input variables of the model were chosen from the available understandings evolved from the previous studies on the strain energy-based liquefaction potential assessment. In order to avoid overtraining, two sets of validation data were employed and a particular monitoring was made on the behavior of the evolved models. Results of a comprehensive parametric study on the proposed model are in accord with the previously published experimental observations. Accordingly, the amount of strain energy required for liquefaction onset increases with increase in initial effective overburden pressure, relative density, and mean grain size. The effect of nonplastic fines on strain energy-based liquefaction resistance shows a more complicated behavior. Accordingly, liquefaction resistance increases with increase in fines up to about 10-15% and then starts to decline for a higher increase in fines content. Further verifications of the model were carried out using the valuable results of some downhole array data as well as centrifuge model tests. These verifications confirm that the proposed model, which was derived from laboratory data, can be successfully utilized under field conditions.

  18. Geometric pre-patterning based tuning of the period doubling onset strain during thin film wrinkling

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Sourabh K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    Wrinkling of supported thin films is an easy-to-implement and low-cost fabrication technique for generation of stretch-tunable periodic micro and nano-scale structures. However, the tunability of such structures is often limited by the emergence of an undesirable period doubled mode at high strains. Predictively tuning the onset strain for period doubling via existing techniques requires one to have extensive knowledge about the nonlinear pattern formation behavior. Herein, a geometric pre-patterning based technique is introduced to delay the onset of period doubling that can be implemented to predictively tune the onset strain even with limited system knowledge. The technique comprises pre-patterning the film/base bilayer with a sinusoidal pattern that has the same period as the natural wrinkle period of the system. The effectiveness of this technique has been verified via physical and computational experiments on the polydimethylsiloxane/glass bilayer system. It is observed that the period doubling onset strain can be increased from the typical value of 20% for flat films to greater than 30% with a modest pre-pattern aspect ratio (2∙amplitude/period) of 0.15. In addition, finite element simulations reveal that (i) the onset strain can be increased up to a limit by increasing the amplitude of the pre-patterns and (ii) the delaying effect can be captured entirely by the pre-pattern geometry. As a result, one can implement this technique even with limited system knowledge, such as material properties or film thickness, by simply replicating pre-existing wrinkled patterns to generate prepatterned bilayers. Thus, geometric pre-patterning is a practical scheme to suppress period doubling that can increase the operating range of stretch-tunable wrinkle-based devices by at least 50%.

  19. Strain Dependence of Photoluminescense of Individual Carbon Nanotubes (United States)

    Nikolaev, Pavel N.; Leeuw, Tonya K.; Tsyboulski, Dmitri A.; Bachilo, Sergei M.; Weisman, Bruce; Arepalli, Sivaram


    We have investigated strain dependence of photoluminescense (PL) spectra of single wall carbon nanotubes (SWNT). Nanotubes were sparsely dispersed in a thin PMMA film applied to acrylic bar, and strained in both compression and extension by bending this bar in either direction in a homebuilt four-point bending rig. The average surface strain was measured with high accuracy by a resistive strain gage applied on top of the film. The near infrared imaging and spectroscopy were performed on the inverted microscope equipped with high numerical aperture reflective objective lens and InGaAs CCD cameras. PL was excited with a diode laser at either 658, 730 or 785 nm, linearly polarized in the direction of the strain. We were able to measure (n,m) types and orientation of individual nanotubes with respect to strain direction and strain dependence of their PL maxima. It was found that PL peak shifts with respect to the values measured in SDS micelles are a sum of three components. First, a small environmental shift due to difference in the dielectric constant of the surrounding media, that is constant and independent of the nanotube type. Second, shift due to isotropic compression of the film during drying. Third, shifts produced by the uniaxial loading of the film in the experiment. Second and third shifts follow expression based on the first-order expansion of the TB hamiltonian. Their magnitude is proportional to the nanotube chiral angle and strain, and direction is determined by the nanotube quantum number. PL strain dependence measured for a number of various nanotube types allows to estimate TB carbon-carbon transfer integral.

  20. Improving snow water equivalent simulations in an alpine basin using blended gage precipitation and snow pillow measurements (United States)

    Sohrabi, M.; Safeeq, M.; Conklin, M. H.


    Snowpack is a critical freshwater reservoir that sustains ecosystem, natural habitat, hydropower, agriculture, and urban water supply in many areas around the world. Accurate estimation of basin scale snow water equivalent (SWE), through both measurement and modeling, has been significantly recognized to improve regional water resource management. Recent advances in remote data acquisition techniques have improved snow measurements but our ability to model snowpack evolution is largely hampered by poor knowledge of inherently variable high-elevation precipitation patterns. For a variety of reasons, majority of the precipitation gages are located in low and mid-elevation range and function as drivers for basin scale hydrologic modeling. Here, we blend observed gage precipitation from low and mid-elevation with point observations of SWE from high-elevation snow pillow into a physically based snow evolution model (SnowModel) to better represent the basin-scale precipitation field and improve snow simulations. To do this, we constructed two scenarios that differed in only precipitation. In WTH scenario, we forced the SnowModel using spatially distributed gage precipitation data. In WTH+SP scenario, the model was forced with spatially distributed precipitation data derived from gage precipitation along with observed precipitation from snow pillows. Since snow pillows do not directly measure precipitation, we uses positive change in SWE as a proxy for precipitation. The SnowModel was implemented at daily time step and 100 m resolution for the Kings River Basin, USA over 2000-2014. Our results show an improvement in snow simulation under WTH+SP as compared to WTH scenario, which can be attributed to better representation in high-elevation precipitation patterns under WTH+SP. The average Nash Sutcliffe efficiency over all snow pillow and course sites was substantially higher for WTH+SP (0.77) than for WTH scenario (0.47). The maximum difference in observed and simulated

  1. Identification Of Some Strains Of Dinoflagellates Based On Morphology And Molecular Analysis

    Directory of Open Access Journals (Sweden)

    Hikmah Thoha


    Full Text Available Dinoflagellates are the important primary producers in aquatic environments. In oceans, they play interesting role in ecological functions such as red tide forming organisms, symbiont of coral reef or sea anemone and DSP (Diarrhetic Shellfish Poisoning or PSP (Paralytic Shellfish Poisoning producing organisms. Morphology and molecular analysis of dinoflagellates were conducted on November 2002 to March 2003. The phylogenetic studies based on 18S rDNA analyses, sequence have begun to appear more frequently in the literature, as attention has turned to relationships within the major eukaryotic lineages, particular importance for the taxonomy of the armored and unarmored genera of dinoflagellates (Gyrodinium sp., Cachonina sp., Gymnodinium sp., Amphidinium sp., because many of the genera cause extensive plankton blooms, fish kills and other harmful events, were studied used to amplify 18S rDNA, present in the total DNA extracted from algal pellet. The amplify approximately 1400 bp of the nuclear-encoded LSU rDNA gene using terminal primeirs DIR, products were cheked by 1.0 % agarose gel electrophoresis, then cloning with TA cloning KIT. Sequencing were analyzed by the GENETIX Mac Software, Homology search by Blast and Phylogenetic analysis. Results of hylogenetic analysis of 18S rDNA are: Strain no. 10893 (un identified from the genera, it is belonging Gymnodinium or Polarella. Strain no. 10795 is closely related other species Cachonina hallii. We tentatively named strain no 11151 and 11160 similar to Gyrodinium or Gymnodinium based on morphology, but these strain indepently position in this tree and is not a real of Gymnodinium sensu stricto. It is possible, we can establish the new genera for strain no. 11151; 11160 because this not cluster any other unarmored species.

  2. Operational verification of a blow out preventer utilizing fiber Bragg grating based strain gauges (United States)

    Turner, Alan L.; Loustau, Philippe; Thibodeau, Dan


    Ultra-deep water BOP (Blowout Preventer) operation poses numerous challenges in obtaining accurate knowledge of current system integrity and component condition- a salient example is the difficulty of verifying closure of the pipe and shearing rams during and after well control events. Ascertaining the integrity of these functions is currently based on a manual volume measurement performed with a stop watch. Advances in sensor technology now permit more accurate methods of BOP condition monitoring. Fiber optic sensing technology and particularly fiber optic strain gauges have evolved to a point where we can derive a good representation of what is happening inside a BOP by installing sensors on the outside shell. Function signatures can be baselined to establish thresholds that indicate successful function activation. Based on this knowledge base, signal variation over time can then be utilized to assess degradation of these functions and subsequent failure to function. Monitoring the BOP from the outside has the advantage of gathering data through a system that can be interfaced with risk based integrity management software and/or a smart monitoring system that analyzes BOP control redundancies without the requirement of interfacing with OEM control systems. The paper will present the results of ongoing work on a fully instrumented 13-½" 10,000 psi pipe ram. Instrumentation includes commonly used pressure transducers, accelerometers, flow meters, and optical strain gauges. Correlation will be presented between flow, pressure, acceleration signatures and the fiber optic strain gauge's response as it relates to functional verification and component level degradation trending.

  3. Development and validation of a strain-based Structural Health Monitoring system (United States)

    Katsikeros, Ch. E.; Labeas, G. N.


    An innovative Structural Health Monitoring (SHM) methodology, based on structural strain measurements, which are processed by a back-propagation feed-forward Artificial Neural Network (ANN), is proposed. The demonstration of the SHM methodology and the identification of its capabilities and drawbacks are performed by applying the method in the prediction of fatigue damage states of a typical aircraft cracked lap-joint structure. An ANN of suitable architecture is developed and trained by numerically generated strain data sets, which have been preprocessed by Fast Fourier Transformation (FFT) for the extraction of the Fourier Descriptors (FDs). The Finite Element (FE) substructuring technique is implemented in the stress and strain analysis of the lap-joint structure, due to its efficiency in the calculation of the numerous strain data, which are necessary for the ANN training. The trained network is successfully validated, as it is proven capable to accurately predict crack positions and lengths of a lap-joint structure, which is damaged by fatigue cracks of unknown location and extent. The proposed methodology is applicable to the identification of more complex types of damage or to other critical structural locations, as its basic concept is generic.

  4. Twin-Core Fiber-Based Mach Zehnder Interferometer for Simultaneous Measurement of Strain and Temperature (United States)

    Kowal, Dominik; Urbanczyk, Waclaw; Mergo, Pawel


    In this paper we present an all-fiber interferometric sensor for the simultaneous measurement of strain and temperature. It is composed of a specially fabricated twin-core fiber spliced between two pieces of a single-mode fiber. Due to the refractive index difference between the two cores in a twin-core fiber, a differential interference pattern is produced at the sensor output. The phase response of the interferometer to strain and temperature is measured in the 850–1250 nm spectral range, showing zero sensitivity to strain at 1000 nm. Due to the significant difference in sensitivities to both parameters, our interferometer is suitable for two-parameter sensing. The simultaneous response of the interferometer to strain and temperature was studied using the two-wavelength interrogation method and a novel approach based on the spectral fitting of the differential phase response. As the latter technique uses all the gathered spectral information, it is more reliable and yields the results with better accuracy. PMID:29558386

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

    Directory of Open Access Journals (Sweden)

    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.

  6. Expression, purification and characterization of the cancer-germline antigen GAGE12I: a candidate for cancer immunotherapy

    DEFF Research Database (Denmark)

    Gjerstorff, Morten F; Besir, Hüseyin; Larsen, Martin R


    GAGE cancer-germline antigens are frequently expressed in a broad range of different cancers, while their expression in normal tissues is limited to the germ cells of the immune privileged organs, testis and ovary. GAGE proteins are immunogenic in humans, which make them promising targets...... for immunotherapy and candidates for cancer vaccines. Recombinant proteins may be superior to peptides as immunogens, since they have the potential to prime both CD4(+) and CD8(+) T cells and are not dependent on patient HLA-type. We have developed a method for production of highly pure recombinant GAGE12I...... filtration and formaldehyde cross-linking indicated that GAGE12I forms tetramers. The purified recombinant GAGE12I represents a candidate molecule for vaccination of cancer patients and will form the basis for further structural analysis of GAGE proteins....

  7. Algal bioremediation of waste waters from land-based aquaculture using ulva: selecting target species and strains.

    Directory of Open Access Journals (Sweden)

    Rebecca J Lawton

    Full Text Available The optimised reduction of dissolved nutrient loads in aquaculture effluents through bioremediation requires selection of appropriate algal species and strains. The objective of the current study was to identify target species and strains from the macroalgal genus Ulva for bioremediation of land-based aquaculture facilities in Eastern Australia. We surveyed land-based aquaculture facilities and natural coastal environments across three geographic locations in Eastern Australia to determine which species of Ulva occur naturally in this region and conducted growth trials at three temperature treatments on a subset of samples from each location to determine whether local strains had superior performance under local environmental conditions. DNA barcoding using the markers ITS and tufA identified six species of Ulva, with U. ohnoi being the most common blade species and U. sp. 3 the most common filamentous species. Both species occurred at multiple land-based aquaculture facilities in Townsville and Brisbane and multiple strains of each species grew well in culture. Specific growth rates of U. ohnoi and U. sp. 3 were high (over 9% and 15% day(-1 respectively across temperature treatments. Within species, strains of U. ohnoi had higher growth in temperatures corresponding to local conditions, suggesting that strains may be locally adapted. However, across all temperature treatments Townsville strains had the highest growth rates (11.2-20.4% day(-1 and Sydney strains had the lowest growth rates (2.5-8.3% day(-1. We also found significant differences in growth between strains of U. ohnoi collected from the same geographic location, highlighting the potential to isolate and cultivate fast growing strains. In contrast, there was no clearly identifiable competitive strain of filamentous Ulva, with multiple species and strains having variable performance. The fast growth rates and broad geographical distribution of U. ohnoi make this an ideal species to

  8. Normalized Rotational Multiple Yield Surface Framework (NRMYSF) stress-strain curve prediction method based on small strain triaxial test data on undisturbed Auckland residual clay soils (United States)

    Noor, M. J. Md; Ibrahim, A.; Rahman, A. S. A.


    Small strain triaxial test measurement is considered to be significantly accurate compared to the external strain measurement using conventional method due to systematic errors normally associated with the test. Three submersible miniature linear variable differential transducer (LVDT) mounted on yokes which clamped directly onto the soil sample at equally 120° from the others. The device setup using 0.4 N resolution load cell and 16 bit AD converter was capable of consistently resolving displacement of less than 1µm and measuring axial strains ranging from less than 0.001% to 2.5%. Further analysis of small strain local measurement data was performed using new Normalized Multiple Yield Surface Framework (NRMYSF) method and compared with existing Rotational Multiple Yield Surface Framework (RMYSF) prediction method. The prediction of shear strength based on combined intrinsic curvilinear shear strength envelope using small strain triaxial test data confirmed the significant improvement and reliability of the measurement and analysis methods. Moreover, the NRMYSF method shows an excellent data prediction and significant improvement toward more reliable prediction of soil strength that can reduce the cost and time of experimental laboratory test.

  9. Substructure based modeling of nickel single crystals cycled at low plastic strain amplitudes (United States)

    Zhou, Dong

    In this dissertation a meso-scale, substructure-based, composite single crystal model is fully developed from the simple uniaxial model to the 3-D finite element method (FEM) model with explicit substructures and further with substructure evolution parameters, to simulate the completely reversed, strain controlled, low plastic strain amplitude cyclic deformation of nickel single crystals. Rate-dependent viscoplasticity and Armstrong-Frederick type kinematic hardening rules are applied to substructures on slip systems in the model to describe the kinematic hardening behavior of crystals. Three explicit substructure components are assumed in the composite single crystal model, namely "loop patches" and "channels" which are aligned in parallel in a "vein matrix," and persistent slip bands (PSBs) connected in series with the vein matrix. A magnetic domain rotation model is presented to describe the reverse magnetostriction of single crystal nickel. Kinematic hardening parameters are obtained by fitting responses to experimental data in the uniaxial model, and the validity of uniaxial assumption is verified in the 3-D FEM model with explicit substructures. With information gathered from experiments, all control parameters in the model including hardening parameters, volume fraction of loop patches and PSBs, and variation of Young's modulus etc. are correlated to cumulative plastic strain and/or plastic strain amplitude; and the whole cyclic deformation history of single crystal nickel at low plastic strain amplitudes is simulated in the uniaxial model. Then these parameters are implanted in the 3-D FEM model to simulate the formation of PSB bands. A resolved shear stress criterion is set to trigger the formation of PSBs, and stress perturbation in the specimen is obtained by several elements assigned with PSB material properties a priori. Displacement increment, plastic strain amplitude control and overall stress-strain monitor and output are carried out in the user

  10. GAGE cancer-germline antigens bind DNA and are recruited to the nuclear envelope by Germ cell-less

    DEFF Research Database (Denmark)

    Gjerstorff, Morten; Rösner, Heike; Pedersen, Christina Bøg

    GAGE genes encode a highly similar, primate-specific protein family with unique primary structure and undefined roles in germ cells, various fetal cells and cancer cells. We report that GAGE proteins are intrinsically disordered proteins that provide novel interfaces between chromatin and the nuc......GAGE genes encode a highly similar, primate-specific protein family with unique primary structure and undefined roles in germ cells, various fetal cells and cancer cells. We report that GAGE proteins are intrinsically disordered proteins that provide novel interfaces between chromatin...... and the nuclear envelope. Structural analysis by NMR and CD spectroscopy showed GAGE proteins lack distinct secondary or tertiary structure and are therefore intrinsically disordered. In normal cells and cancer cells GAGE proteins localize predominantly in the nucleus; we found GAGE proteins formed stable......) at the nuclear envelope. Furthermore, exogenous and endogenous GAGE proteins were recruited to the nuclear envelope in GCL-overexpressing cells. Gene expression analysis and immunohistochemical staining suggest GAGE proteins and GCL interact physiologically in human cells that express both, including male germ...

  11. Prediction of stress- and strain-based forming limits of automotive thin sheets by numerical, theoretical and experimental methods (United States)

    Béres, Gábor; Weltsch, Zoltán; Lukács, Zsolt; Tisza, Miklós


    Forming limit is a complex concept of limit values related to the onset of local necking in the sheet metal. In cold sheet metal forming, major and minor limit strains are influenced by the sheet thickness, strain path (deformation history) as well as material parameters and microstructure. Forming Limit Curves are plotted in ɛ1 - ɛ2 coordinate system providing the classic strain-based Forming Limit Diagram (FLD). Using the appropriate constitutive model, the limit strains can be changed into the stress-based Forming Limit Diagram (SFLD), irrespective of the strain path. This study is about the effect of the hardening model parameters on defining of limit stress values during Nakazima tests for automotive dual phase (DP) steels. Five limit strain pairs were specified experimentally with the loading of five different sheet geometries, which performed different strain-paths from pure shear (-2ɛ2=ɛ1) up to biaxial stretching (ɛ2=ɛ1). The former works of Hill, Levy-Tyne and Keeler-Brazier made possible some kind of theoretical strain determination, too. This was followed by the stress calculation based on the experimental and theoretical strain data. Since the n exponent in the Nádai expression is varying with the strain at some DP steels, we applied the least-squares method to fit other hardening model parameters (Ludwik, Voce, Hockett-Sherby) to calculate the stress fields belonging to each limit strains. The results showed that each model parameters could produce some discrepancies between the limit stress states in the range of higher equivalent strains than uniaxial stretching. The calculated hardening models were imported to FE code to extend and validate the results by numerical simulations.

  12. Strain measurement on a compact nuclear reactor steam generator

    International Nuclear Information System (INIS)

    Scaldaferri, Denis Henrique Bianchi; Gomes, Paulo de Tarso Vida; Mansur, Tanius Rodrigues; Pozzo, Renato del; Mola, Jairo


    This work presents the strain measurement procedures applied to a compact nuclear reactor steam generator, during a hydrostatic test, using strain gage technology. The test was divided in two steps: primary side test and secondary side test. In the primary side test twelve points for strain measurement using rectangular rosettes, three points (two external and one internal) for temperature measurement using special strain gages and one point for pressure measurement using a pressure transducer were monitored. In the secondary side test 18 points for strain measurement using rectangular rosettes, four points (two external and two internal) for temperature measurement using special strain gages and one point for pressure measurement using a pressure transducer were monitored. The measurement points on both internal and external pressurizer walls were established from pre-calculated stress distribution by means of numerical approach (finite elements modeling). Strain values using a quarter Wheatstone bridge circuit were obtained. Stress values, from experimental strain were determined, and to numerical calculation results were compared. (author)

  13. Vibration based monitoring of stay cable force using wireless piezoelectric based strain sensor nodes

    International Nuclear Information System (INIS)

    Nguyen, Khac Duy; Kim, Jeong Tae


    This study presents a method to monitor cable force using wireless sensor nodes and piezoelectric sensors. The following approaches are carried out to achieve the objective. Firstly, the principle of piezoelectric materials (e.g., PZT) as strain sensors is reviewed. A cable force estimation method using dynamic features of cables measured by piezoelectric materials is presented. Secondly, the design of an automated cable force monitoring system using the data acquisition sensor node Imote2/SHM DAQ is described. The sensor node is originally developed by University of Illinois at Urbana champaign and is adopted in this study to monitor strain induced voltage from PZT sensors. The advantages of the system are cheap, and eligible for wireless communication and automated operation. Finally, the feasibility of the proposed monitoring system is evaluated on a lab scaled cable

  14. Strain sensitivity of carbon nanotube cement-based composites for structural health monitoring (United States)

    D'Alessandro, Antonella; Ubertini, Filippo; Laflamme, Simon; Rallini, Marco; Materazzi, Annibale L.; Kenny, Josè M.


    Cement-based smart sensors appear particularly suitable for monitoring applications, due to their self-sensing abilities, their ease of use, and their numerous possible field applications. The addition of conductive carbon nanofillers into a cementitious matrix provides the material with piezoresistive characteristics and enhanced sensitivity to mechanical alterations. The strain-sensing ability is achieved by correlating the variation of external loads or deformations with the variation of specific electrical parameters, such as the electrical resistance. Among conductive nanofillers, carbon nanotubes (CNTs) have shown promise for the fabrication of self-monitoring composites. However, some issues related to the filler dispersion and the mix design of cementitious nanoadded materials need to be further investigated. For instance, a small difference in the added quantity of a specific nanofiller in a cement-matrix composite can substantially change the quality of the dispersion and the strain sensitivity of the resulting material. The present research focuses on the strain sensitivity of concrete, mortar and cement paste sensors fabricated with different amounts of carbon nanotube inclusions. The aim of the work is to investigate the quality of dispersion of the CNTs in the aqueous solutions, the physical properties of the fresh mixtures, the electromechanical properties of the hardened materials, and the sensing properties of the obtained transducers. Results show that cement-based sensors with CNT inclusions, if properly implemented, can be favorably applied to structural health monitoring.

  15. Strain-Based Damage Determination Using Finite Element Analysis for Structural Health Management (United States)

    Hochhalter, Jacob D.; Krishnamurthy, Thiagaraja; Aguilo, Miguel A.


    A damage determination method is presented that relies on in-service strain sensor measurements. The method employs a gradient-based optimization procedure combined with the finite element method for solution to the forward problem. It is demonstrated that strains, measured at a limited number of sensors, can be used to accurately determine the location, size, and orientation of damage. Numerical examples are presented to demonstrate the general procedure. This work is motivated by the need to provide structural health management systems with a real-time damage characterization. The damage cases investigated herein are characteristic of point-source damage, which can attain critical size during flight. The procedure described can be used to provide prognosis tools with the current damage configuration.

  16. Wearable Wide-Range Strain Sensors Based on Ionic Liquids and Monitoring of Human Activities

    Directory of Open Access Journals (Sweden)

    Shao-Hui Zhang


    Full Text Available Wearable sensors for detection of human activities have encouraged the development of highly elastic sensors. In particular, to capture subtle and large-scale body motion, stretchable and wide-range strain sensors are highly desired, but still a challenge. Herein, a highly stretchable and transparent stain sensor based on ionic liquids and elastic polymer has been developed. The as-obtained sensor exhibits impressive stretchability with wide-range strain (from 0.1% to 400%, good bending properties and high sensitivity, whose gauge factor can reach 7.9. Importantly, the sensors show excellent biological compatibility and succeed in monitoring the diverse human activities ranging from the complex large-scale multidimensional motions to subtle signals, including wrist, finger and elbow joint bending, finger touch, breath, speech, swallow behavior and pulse wave.

  17. A study of microindentation hardness tests by mechanism-based strain gradient plasticity

    International Nuclear Information System (INIS)

    Huang, Y.; Xue, Z.; Gao, H.; Nix, W. D.; Xia, Z. C.


    We recently proposed a theory of mechanism-based strain gradient (MSG) plasticity to account for the size dependence of plastic deformation at micron- and submicron-length scales. The MSG plasticity theory connects micron-scale plasticity to dislocation theories via a multiscale, hierarchical framework linking Taylor's dislocation hardening model to strain gradient plasticity. Here we show that the theory of MSG plasticity, when used to study micro-indentation, indeed reproduces the linear dependence observed in experiments, thus providing an important self-consistent check of the theory. The effects of pileup, sink-in, and the radius of indenter tip have been taken into account in the indentation model. In accomplishing this objective, we have generalized the MSG plasticity theory to include the elastic deformation in the hierarchical framework. (c) 2000 Materials Research Society

  18. Strain gradient plasticity-based modeling of hydrogen environment assisted cracking

    DEFF Research Database (Denmark)

    Martínez Pañeda, Emilio; Niordson, Christian Frithiof; P. Gangloff, Richard


    Finite element analysis of stress about a blunt crack tip, emphasizing finite strain and phenomenologicaland mechanism-based strain gradient plasticity (SGP) formulations, is integrated with electrochemical assessment of occluded-crack tip hydrogen (H) solubility and two H-decohesion models...... to predict hydrogen environment assisted crack growth properties. SGP elevates crack tip geometrically necessary dislocation density and flow stress, with enhancement declining with increasing alloy strength. Elevated hydrostatic stress promotes high-trapped H concentration for crack tip damage......; it is imperative to account for SGP in H cracking models. Predictions of the threshold stress intensity factor and H-diffusion limited Stage II crack growth rate agree with experimental data for a high strength austenitic Ni-Cusuperalloy (Monel®K-500) and two modern ultra-high strength martensitic steels (Aer...

  19. Fast recovery strain measurements in a nuclear test environment

    International Nuclear Information System (INIS)

    Kitchen, W.R.; Nauman, W.J.; Vollmer, D.W.


    The recovery of early-time (50 μs or less) strain gage data on structural response experiments in underground nuclear tests has been a continuing problem for experimenters at the Nevada Test Site. Strain measurement is one of the primary techniques used to obtain experimental data for model verification and correlation with predicted effects. Peak strains generally occur within 50 to 100 μs of the radiation exposure. Associated with the exposure is an intense electromagnetic impulse that produces potentials of kilovolts and currents of kiloamperes on the experimental structures. For successful operation, the transducer and associated recording system must recover from the initial noise overload and accurately track the strain response within about 50 μs of the nuclear detonation. A gaging and fielding technique and a recording system design that together accomplish these objectives are described. Areas discussed include: (1) noise source model; (2) experimental cassette design, gage application, grounding, and shielding; (3) cable design and shielding between gage and recorder; (4) recorder design including signal conditioner/amplifier, digital encoder, buffer memory, and uphole data transmission; and (5) samples of experimental data

  20. Cost-effectiveness of the stream-gaging program in Maine; a prototype for nationwide implementation (United States)

    Fontaine, Richard A.; Moss, M.E.; Smath, J.A.; Thomas, W.O.


    This report documents the results of a cost-effectiveness study of the stream-gaging program in Maine. Data uses and funding sources were identified for the 51 continuous stream gages currently being operated in Maine with a budget of $211,000. Three stream gages were identified as producing data no longer sufficiently needed to warrant continuing their operation. Operation of these stations should be discontinued. Data collected at three other stations were identified as having uses specific only to short-term studies; it is recommended that these stations be discontinued at the end of the data-collection phases of the studies. The remaining 45 stations should be maintained in the program for the foreseeable future. The current policy for operation of the 45-station program would require a budget of $180,300 per year. The average standard error of estimation of streamflow records is 17.7 percent. It was shown that this overall level of accuracy at the 45 sites could be maintained with a budget of approximately $170,000 if resources were redistributed among the gages. A minimum budget of $155,000 is required to operate the 45-gage program; a smaller budget would not permit proper service and maintenance of the gages and recorders. At the minimum budget, the average standard error is 25.1 percent. The maximum budget analyzed was $350,000, which resulted in an average standard error of 8.7 percent. Large parts of Maine's interior were identified as having sparse streamflow data. It was determined that this sparsity be remedied as funds become available.

  1. Quantification of carotid artery plaque stability with multiple region of interest based ultrasound strain indices and relationship with cognition (United States)

    Meshram, N. H.; Varghese, T.; Mitchell, C. C.; Jackson, D. C.; Wilbrand, S. M.; Hermann, B. P.; Dempsey, R. J.


    Vulnerability and instability in carotid artery plaque has been assessed based on strain variations using noninvasive ultrasound imaging. We previously demonstrated that carotid plaques with higher strain indices in a region of interest (ROI) correlated to patients with lower cognition, probably due to cerebrovascular emboli arising from these unstable plaques. This work attempts to characterize the strain distribution throughout the entire plaque region instead of being restricted to a single localized ROI. Multiple ROIs are selected within the entire plaque region, based on thresholds determined by the maximum and average strains in the entire plaque, enabling generation of additional relevant strain indices. Ultrasound strain imaging of carotid plaques, was performed on 60 human patients using an 18L6 transducer coupled to a Siemens Acuson S2000 system to acquire radiofrequency data over several cardiac cycles. Patients also underwent a battery of neuropsychological tests under a protocol based on National Institute of Neurological Disorders and Stroke and Canadian Stroke Network guidelines. Correlation of strain indices with composite cognitive index of executive function revealed a negative association relating high strain to poor cognition. Patients grouped into high and low cognition groups were then classified using these additional strain indices. One of our newer indices, namely the average L  -  1 norm with plaque (AL1NWP) presented with significantly improved correlation with executive function when compared to our previously reported maximum accumulated strain indices. An optimal combination of three of the new indices generated classifiers of patient cognition with an area under the curve (AUC) of 0.880, 0.921 and 0.905 for all (n  =  60), symptomatic (n  =  33) and asymptomatic patients (n  =  27) whereas classifiers using maximum accumulated strain indices alone provided AUC values of 0.817, 0.815 and 0

  2. Behavior of porous beryllium under thermomechanical loading. Part 7. Calibration studies on the carbon piezoresistive gage

    International Nuclear Information System (INIS)

    Horning, R.R.; Isbell, W.M.


    The calibrations, time responses, and Hugoniot for carbon piezoresistive gages from two manufacturers are presented. These gages exhibit a high sensitivity of about --20 percent resistance change per GPa at 0.5 GPa. Their equilibrium times, when tested in fused silica, exceed 0.6 μs below 0.5 GPa but improve at higher stresses and under better impedance matching conditions. They can be made of low atomic number materials, making them interesting candidates for studying the mechanical responses of materials to electron and x-ray deposition. (U.S.)

  3. A piezoelectric-based infinite stiffness generation method for strain-type load sensors

    International Nuclear Information System (INIS)

    Zhang, Shuwen; Shao, Shubao; Xu, Minglong; Chen, Jie


    Under certain application conditions like nanoindentation technology and the mechanical property measurement of soft materials, the elastic deformation of strain-type load sensors affects their displacement measurement accuracy. In this work, a piezoelectric-based infinite stiffness generation method for strain-type load sensors that compensates for this elastic deformation is presented. The piezoelectric material-based deformation compensation method is proposed. An Hottinger Baldwin Messtechnik GmbH (HBM) Z30A/50N load sensor acts as the foundation of the method presented in this work. The piezoelectric stack is selected based on its size, maximum deformation value, blocking force and stiffness. Then, a clamping and fixing structure is designed to integrate the HBM sensor with the piezoelectric stack. The clamping and fixing structure, piezoelectric stack and HBM load sensor comprise the sensing part of the enhanced load sensor. The load-deformation curve and the voltage-deformation curve of the enhanced load sensor are then investigated experimentally. Because a hysteresis effect exists in the piezoelectric structure, the relationship between the control signal and the deformation value of the piezoelectric material is nonlinear. The hysteresis characteristic in a quasi-static condition is studied and fitted using a quadratic polynomial, and its coefficients are analyzed to enable control signal prediction. Applied arithmetic based on current theory and the fitted data is developed to predict the control signal. Finally, the experimental effects of the proposed method are presented. It is shown that when a quasi-static load is exerted on this enhanced strain-type load sensor, the deformation is reduced and the equivalent stiffness appears to be almost infinite. (paper)

  4. Lattice and strain analysis of atomic resolution Z-contrast images based on template matching

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Jian-Min, E-mail: [Department of Materials Science and Engineering, University of Illinois, Urbana, IL 61801 (United States); Seitz Materials Research Laboratory, University of Illinois, Urbana, IL 61801 (United States); Shah, Amish B. [Center for Microanalysis of Materials, Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Kim, Honggyu; Meng, Yifei; Gao, Wenpei [Department of Materials Science and Engineering, University of Illinois, Urbana, IL 61801 (United States); Seitz Materials Research Laboratory, University of Illinois, Urbana, IL 61801 (United States); Rouviére, Jean-Luc [CEA-INAC/UJF-Grenoble UMR-E, SP2M, LEMMA, Minatec, Grenoble 38054 (France)


    A real space approach is developed based on template matching for quantitative lattice analysis using atomic resolution Z-contrast images. The method, called TeMA, uses the template of an atomic column, or a group of atomic columns, to transform the image into a lattice of correlation peaks. This is helped by using a local intensity adjusted correlation and by the design of templates. Lattice analysis is performed on the correlation peaks. A reference lattice is used to correct for scan noise and scan distortions in the recorded images. Using these methods, we demonstrate that a precision of few picometers is achievable in lattice measurement using aberration corrected Z-contrast images. For application, we apply the methods to strain analysis of a molecular beam epitaxy (MBE) grown LaMnO{sub 3} and SrMnO{sub 3} superlattice. The results show alternating epitaxial strain inside the superlattice and its variations across interfaces at the spatial resolution of a single perovskite unit cell. Our methods are general, model free and provide high spatial resolution for lattice analysis. - Highlights: • A real space approach is developed for strain analysis using atomic resolution Z-contrast images and template matching. • A precision of few picometers is achievable in the measurement of lattice displacements. • The spatial resolution of a single perovskite unit cell is demonstrated for a LaMnO{sub 3} and SrMnO{sub 3} superlattice grown by MBE.

  5. Evaluation of the dynamic behavior of a Pelton runner based on strain gauge measurements (United States)

    Mack, Reiner; Probst, Christian


    A reliable mechanical design of Pelton runners is very important in the layout of new installations and modernizations. Especially in horizontal machines, where the housing is not embedded into concrete, a rupture of a runner bucket can have severe consequences. Even if a crack in the runner is detected on time, the outage time that follows the malfunction of the runner is shortening the return of investment. It is a fact that stresses caused by the runner rotation and the jet forces are superposed by high frequent dynamic stresses. In case of resonance it even can be the dominating effect that is limiting the lifetime of a runner. Therefore a clear understanding of the dynamic mechanisms is essential for a safe runner design. This paper describes the evaluation of the dynamic behavior of a Pelton runner installed in a model turbine based on strain gauge measurements. Equipped with strain gauges at the root area of the buckets, the time responses of the strains under the influence of various operational parameters were measured. As a result basic theories for the jet bucket excitation were verified and the influence of the water mass was detected by evaluating the frequency shift in case of resonance. Furthermore, the influence of the individual bucket masses onto the dynamic behaviour for different mode shapes got measured.

  6. Tensile behaviour of geopolymer-based materials under medium and high strain rates (United States)

    Menna, Costantino; Asprone, Domenico; Forni, Daniele; Roviello, Giuseppina; Ricciotti, Laura; Ferone, Claudio; Bozza, Anna; Prota, Andrea; Cadoni, Ezio


    Geopolymers are a promising class of inorganic materials typically obtained from an alluminosilicate source and an alkaline solution, and characterized by an amorphous 3-D framework structure. These materials are particularly attractive for the construction industry due to mechanical and environmental advantages they exhibit compared to conventional systems. Indeed, geopolymer-based concretes represent a challenge for the large scale uses of such a binder material and many research studies currently focus on this topic. However, the behaviour of geopolymers under high dynamic loads is rarely investigated, even though it is of a fundamental concern for the integrity/vulnerability assessment under extreme dynamic events. The present study aims to investigate the effect of high dynamic loading conditions on the tensile behaviour of different geopolymer formulations. The dynamic tests were performed under different strain rates by using a Hydro-pneumatic machine and a modified Hopkinson bar at the DynaMat laboratory of the University of Applied Sciences of Southern Switzerland. The results are processed in terms of stress-strain relationships and strength dynamic increase factor at different strain-rate levels. The dynamic increase factor was also compared with CEB recommendations. The experimental outcomes can be used to assess the constitutive laws of geopolymers under dynamic load conditions and implemented into analytical models.

  7. Strain ageing and yield plateau phenomena in γ-TiAl based alloys containing boron

    International Nuclear Information System (INIS)

    Cheng, T.T.; Bate, P.S.; Botten, R.R.; Lipsitt, H.A.


    There has been considerable interest over the past few years in γ-TiAl based alloys since they offer a combination of low density and useful mechanical properties at temperatures higher than those possible with conventional titanium alloys. However, there are still serious limitations to their use in engineering components due to their limited ductility and fracture toughness. Much of the recent work has been focused on improving the room temperature ductility of these materials, and a significant part of the work has been involved with studying the effects of thermo-mechanical processing (TMP) and alloying. One of the alloying additions which has received much attention is boron. Addition of boron (≥0.5 at.%) leads to refined as-cast grain structures and can increase the strength and ductility of these alloys. If boron does segregate to grain boundaries, it would be expected that segregation would also occur at dislocations, which can result in solute locking and yield point phenomena. Nakano and Umakoshi's results show some signs of this, with regions of distinct upward curvature in stress-strain curves for boron-containing material, although the flow stress was always increasing with strain. Evidence of strain ageing in TiAl alloys containing boron has also been reported by Wheeler et al., and the work reported here also suggests that boron can act to produce solute locking of glide dislocations in a different class of near γ-TiAl alloys

  8. Analysis of structures based on a characteristic-strain model of creep

    Energy Technology Data Exchange (ETDEWEB)

    Bolton, J. [Alstom Power, Newbold Road, Rugby CV21 2NH (United Kingdom)], E-mail:


    A companion paper [Bolton J. In: A characteristic-strain model for creep, ECCC/I.Mech.E. conference on creep and fracture in high-temperature components, London, September 2005] describes a creep model based on a constant 'characteristic strain' at any temperature. The present paper discusses the application of such a model, first to simple structures and then to engineering components of general form under steady loading. A basis is proposed for identifying the stress within a structure, or within the critical part of a structure, which can be considered to govern both its overall and local deformations. The concept is similar to skeletal-point stress but is more readily applied to components of any shape. The implementation of the concept of 'structural stress' is discussed in the context of finite-element creep calculations. Consideration is given to the analysis of cracked structures, where very high strains at the crack tip must be accommodated.

  9. Carbon nanotubes (CNTs) based strain sensors for a wearable monitoring and biofeedback system for pressure ulcer prevention and rehabilitation. (United States)

    Boissy, Patrick; Genest, Jonathan; Patenaude, Johanne; Poirier, Marie-Sol; Chenel, Vanessa; Béland, Jean-Pierre; Legault, Georges-Auguste; Bernier, Louise; Tapin, Danielle; Beauvais, Jacques


    This paper presents an overview of the functioning principles of CNTs and their electrical and mechanical properties when used as strain sensors and describes a system embodiment for a wearable monitoring and biofeedback platform for use in pressure ulcer prevention and rehabilitation. Two type of CNTs films (multi-layered CNTs film vs purified film) were characterized electrically and mechanically for potential use as source material. The loosely woven CNTs film (multi-layered) showed substantial less sensitivity than the purified CNTs film but had an almost linear response to stress and better mechanical properties. CNTs have the potential to achieve a much higher sensitivity to strain than other piezoresistors based on regular of conductive particles such as commercially available resistive inks and could become an innovative source material for wearable strain sensors. We are currently continuing the characterization of CNTs based strain sensors and exploring their use in a design for 3-axis strain sensors.

  10. Kirigami-based PVDF thin-film as stretchable strain sensor (United States)

    Hu, Nan; Chen, Dajing; Hao, Nanjing; Huang, Shicheng; Yu, Xiaojiao; Zhang, John X. J.; Chen, Zi

    Kirigami, as the sister of the origami, involves cutting of 2D sheets to form complex 3D geometries with out-of-plane patterns. Motivated by the development of the high-stretchable biomedical devices, we explore the stretchability of the kirigami-based PVDF thin film under tension. Our structural prototypes include a set of 2D geometry with kirigami-based pattern cutting on PVDF thin films. We first used paper models to generate a wide range of cutting patterns to study the deformation under compression tests, the results of which are compared with finite element simulations. We then proceeded to test different kirigami-based designs to identify geometric parameters that can tune the post-buckling response and strain distribution. Next, we fabricated and tested the PVDF thin film with kirigami pattern. Experiments showed that the PVDF film in the absence of cutting can be stretched to a limited extent and will break upon further stretching. In contrast, the kirigami-based films can be stretched up to 100% without failure. Our designs demonstrate the ability to significantly improve the strain range of the structure and sensing ability of a sensor. We envision a promising future to use this class of structural elements to develop highly stretchable materials, structures, and devices. Z.C. acknowledges the Society in Science-Branco Weiss fellowship, administered by ETH Zürich. J.X.J.Z. acknowledges the NIH Director's Transformative Research Award (1R01 OD022910-01).

  11. Identification and characterization of Lactococcus starter strains in milk-based traditional fermented products in the region of Iran

    Directory of Open Access Journals (Sweden)

    Farzad Rahmati


    Full Text Available The aim of the present research was identification and investigation of technological attributes of Lactococcus starter strains from traditional dairy products collected from the countryside of Boroujerd in Iran. 33 samples were cultured on selective media M17 and typical colonies surveyed for morphological properties. Totally, 37 strains were isolated based on the diversity in cell morphology and identified using API galleries and carbohydrate fermentation includes 17 strains of Lactococcus lactis (45.96%, 12 strains of Lactococcus garvieae (32.43% and 8 strains of Lactococcusplantarum (21.62%. Strains were appraised for hydrolysis of L-arginine, casein and starch. Furthermore, strains were evaluated for the ability to grow at temperature 10 °C, 45 °C and presence of 4% and 6.5% NaCl, antibiotic sensitivity, acidification ability, proteolytic and lipolytic activities. Generally, 3 strains of Lc.garvieae (GYLC1, BWLC1, DCLC1 and 7 strains of Lc. lactis (GCLC4, GWLC2, GWLC3, SWLC1, SWLC3, BCLC5, DYLC1 exposed the highest levels of technological properties in order to use as starter cultures.

  12. Monitoring the State of the Magmatic Structures of Elbrus Volcano Based on Observation of Lithosphere Strains

    International Nuclear Information System (INIS)

    Milyukov, Vadim; Myasnikov, Andrey; Mironov, Alexey


    An analysis of crustal strain recorded by the Baksan laser interferometer revealed a shallow magma chamber in the structure of Elbrus Volcano (The Northern Caucasus, Russia). The analysis is based on estimation of parameters of magmatic structures resonant modes excited by teleseismic signals. The resonance parameters we have found were interpreted in the framework of contemporary models of magma resonators. The depth and dimension of the magma chamber, as well as the properties of the magma fluid were estimated. It was suggested the changing the magma state due to rising the intrachamber pressure

  13. Characterization of high-strain rate mechanical behavior of AZ31 magnesium alloy using 3D digital image correlation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanli; Xu, Hanbing; Erdman, Donald L.; Starbuck, Michael J.; Simunovic, Srdjan [Oak Ridge National Laboratory, Oak Ridge, TN (United States)


    Characterization of the material mechanical behavior at sub-Hopkinson regime (0.1 to 1 000 s{sup -1}) is very challenging due to instrumentation limitations and the complexity of data analysis involved in dynamic loading. In this study, AZ31 magnesium alloy sheet specimens are tested using a custom designed servo-hydraulic machine in tension at nominal strain rates up to 1 000 s{sup -1}. In order to resolve strain measurement artifacts, the specimen displacement is measured using 3D Digital Image correlation instead from actuator motion. The total strain is measured up to {approx} 30%, which is far beyond the measurable range of electric resistance strain gages. Stresses are calculated based on the elastic strains in the tab of a standard dog-bone shaped specimen. Using this technique, the stresses measured for strain rates of 100 s{sup -1} and lower show little or no noise comparing to load cell signals. When the strain rates are higher than 250 s{sup -1}, the noises and oscillations in the stress measurements are significantly decreased from {approx} 250 to 50 MPa. Overall, it is found that there are no significant differences in the elongation, although the material exhibits slight work hardening when the strain rate is increased from 1 to 100 s{sup -1}. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Dualband MW/LW Strained Layer Superlattice Focal Plane Arrays for Satellite-Based Wildfire Detection, Phase II (United States)

    National Aeronautics and Space Administration — Infrared focal plane arrays (FPAs) based on Type-II strained layer superlattice (SLS) photodiodes have recently experienced significant advances. In Phase I we...

  15. Dualband MW/LW Strained Layer Superlattice Focal Plane Arrays For Satellite-Based Wildfire Detection, Phase I (United States)

    National Aeronautics and Space Administration — Dualband focal plane arrays (FPAs) based on gallium-free Type-II strained layer superlattice (SLS) photodiodes have recently experienced significant advances. We...

  16. Sex-Based Differences in Knee Kinetics With Anterior Cruciate Ligament Strain on Cadaveric Impact Simulations (United States)

    Schilaty, Nathan D.; Bates, Nathaniel A.; Nagelli, Christopher; Krych, Aaron J.; Hewett, Timothy E.


    maximum difference of 54.3-N·m increased abduction torque and 74.5-N·m increased abduction torque at 66 milliseconds postimpact. Conclusion: Under the tested conditions, increased external loads led to increased medial knee translation force, knee abduction moment, and external knee moment. Females exhibited greater forces and moments at the knee, especially at KAM, when loaded in similar conditions. As these KAM loads are associated with increased load and strain on the ACL, the sex-based differences observed in the present study may account for a portion of the underlying mechanics that predispose females to ACL injury as compared with males in a controlled simulated athletic task. Clinical Relevance: KAM increases strain to the ACL under clinically representative loading. Additionally, this work establishes the biomechanical characteristics of knee loading between sexes. PMID:29568787

  17. Arrangement for correcting values measured by mass per unit area or thickness gages

    International Nuclear Information System (INIS)

    Volger, G.; Sandke, E.; Heinz, P.


    The described arrangement can be applied to gaged making use of beta radiation and of a protective screen for shielding the radiation source and the ionization chamber of the measuring instrument. It has been aimed at counterbalancing measuring inaccuracies caused by temperature fluctuations in the measuring slot

  18. THz-wave generation via difference frequency mixing in strained silicon based waveguide utilizing its second order susceptibility χ((2)). (United States)

    Saito, Kyosuke; Tanabe, Tadao; Oyama, Yutaka


    Terahertz (THz) wave generation via difference frequency mixing (DFM) process in strain silicon membrane waveguides by introducing the straining layer is theoretically investigated. The Si(3)N(4) straining layer induces anisotropic compressive strain in the silicon core and results in the appearance of the bulk second order nonlinear susceptibility χ((2)) by breaking the crystal symmetry. We have proposed waveguide structures for THz wave generation under the DFM process by .using the modal birefringence in the waveguide core. Our simulations show that an output power of up to 0.95 mW can be achieved at 9.09 THz. The strained silicon optical device may open a widow in the field of the silicon-based active THz photonic device applications.

  19. Development of a fiber optic pavement subgrade strain measurement system (United States)

    Miller, Craig Emerson


    This dissertation describes the development of a fiber optic sensing system to measure strains within the soil subgrade of highway pavements resulting from traffic loads. The motivation to develop such a device include improvements to: (1)all phases of pavement design, (2)theoretical models used to predict pavement performance, and (3)pavement rehabilitation. The design of the sensing system encompasses selecting an appropriate transducer design as well as the development of optimal optical and demodulation systems. The first is spring based, which attempts to match its spring stiffness to that of the soil-data indicate it is not an optimal transducer design. The second transducer implements anchoring plates attached to two telescoping tubes which allows the soil to be compacted to a desired density between the plates to dictate the transducer's behavior. Both transducers include an extrinsic Fabry- Perot cavity to impose the soil strains onto a phase change of the optical signal propagating through the cavity. The optical system includes a low coherence source and allows phase modulation via path length stretching by adding a second interferometer in series with the transducer, resulting in a path matched differential interferometer. A digitally implemented synthetic heterodyne demodulator based on a four step phase stepping algorithm is used to obtain unambiguous soil strain information from the displacement of the Fabry-Perot cavity. The demodulator is calibrated and characterized by illuminating the transducer with a second long coherence source of different wavelength. The transducer using anchoring plates is embedded within cylindrical soil specimens of varying soil types and soil moisture contents. Loads are applied to the specimen and resulting strains are measured using the embedded fiber optic gage and LVDTs attached to the surface of the specimen. This experimental verification is substantiated using a finite element analysis to predict any differences

  20. A Novel Strain-Based Method to Estimate Tire Conditions Using Fuzzy Logic for Intelligent Tires

    Directory of Open Access Journals (Sweden)

    Daniel Garcia-Pozuelo


    Full Text Available The so-called intelligent tires are one of the most promising research fields for automotive engineers. These tires are equipped with sensors which provide information about vehicle dynamics. Up to now, the commercial intelligent tires only provide information about inflation pressure and their contribution to stability control systems is currently very limited. Nowadays one of the major problems for intelligent tire development is how to embed feasible and low cost sensors to obtain reliable information such as inflation pressure, vertical load or rolling speed. These parameters provide key information for vehicle dynamics characterization. In this paper, we propose a novel algorithm based on fuzzy logic to estimate the mentioned parameters by means of a single strain-based system. Experimental tests have been carried out in order to prove the suitability and durability of the proposed on-board strain sensor system, as well as its low cost advantages, and the accuracy of the obtained estimations by means of fuzzy logic.

  1. Footprints of phineas gage: Historical beginnings on the origins of brain and behavior and the birth of cerebral localizationism

    Directory of Open Access Journals (Sweden)

    Bhaskara P Shelley


    Full Text Available The intellectual revolution led by ancient Greek philosophers and physicians witnessed the extraordinary evolution of the birth of neuroscience from speculations of cardiocentrism (Aristotelism and encephalocentrism (Galenism. Later further development of neurosciences was hallmarked by the development of anatomic theories of phrenology by the German physician Franz Joseph Gall in 1796. Although phrenology was a pseudoscience, it was Gall who laid the foundations for the subsequent biologically based doctrine of brain behavior localization. The amazing story of Phineas Gage is a classic case in the nineteenth-century neurosciences literature that played a pivotal role in the concept of cerebral localizationism, a theory that moved beyond phrenology. This iconic case marked the historical beginnings of brain origins of human behavior and elucidated a link between brain trauma, prefrontal brain damage and personality change.

  2. An analytical method for calculating stresses and strains of ATF cladding based on thick walled theory

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Hyun; Kim, Hak Sung [Hanyang University, Seoul (Korea, Republic of); Kim, Hyo Chan; Yang, Yong Sik; In, Wang kee [KAERI, Daejeon (Korea, Republic of)


    In this paper, an analytical method based on thick walled theory has been studied to calculate stress and strain of ATF cladding. In order to prescribe boundary conditions of the analytical method, two algorithms were employed which are called subroutine 'Cladf' and 'Couple' of FRACAS, respectively. To evaluate the developed method, equivalent model using finite element method was established and stress components of the method were compared with those of equivalent FE model. One of promising ATF concepts is the coated cladding, which take advantages such as high melting point, a high neutron economy, and low tritium permeation rate. To evaluate the mechanical behavior and performance of the coated cladding, we need to develop the specified model to simulate the ATF behaviors in the reactor. In particular, the model for simulation of stress and strain for the coated cladding should be developed because the previous model, which is 'FRACAS', is for one body model. The FRACAS module employs the analytical method based on thin walled theory. According to thin-walled theory, radial stress is defined as zero but this assumption is not suitable for ATF cladding because value of the radial stress is not negligible in the case of ATF cladding. Recently, a structural model for multi-layered ceramic cylinders based on thick-walled theory was developed. Also, FE-based numerical simulation such as BISON has been developed to evaluate fuel performance. An analytical method that calculates stress components of ATF cladding was developed in this study. Thick-walled theory was used to derive equations for calculating stress and strain. To solve for these equations, boundary and loading conditions were obtained by subroutine 'Cladf' and 'Couple' and applied to the analytical method. To evaluate the developed method, equivalent FE model was established and its results were compared to those of analytical model. Based on the

  3. Standard guide for high-temperature static strain measurement

    CERN Document Server

    American Society for Testing and Materials. Philadelphia


    1.1 This guide covers the selection and application of strain gages for the measurement of static strain up to and including the temperature range from 425 to 650°C (800 to 1200°F). This guide reflects some current state-of-the-art techniques in high temperature strain measurement, and will be expanded and updated as new technology develops. 1.2 This practice assumes that the user is familiar with the use of bonded strain gages and associated signal conditioning and instrumentation as discussed in Refs. (1) and (2). The strain measuring systems described are those that have proven effective in the temperature range of interest and were available at the time of issue of this practice. It is not the intent of this practice to limit the user to one of the gage types described nor is it the intent to specify the type of system to be used for a specific application. However, in using any strain measuring system including those described, the proposer must be able to demonstrate the capability of the proposed sy...

  4. Textile-Based, Interdigital, Capacitive, Soft-Strain Sensor for Wearable Applications

    Directory of Open Access Journals (Sweden)

    Ozgur Atalay


    Full Text Available The electronic textile area has gained considerable attention due to its implementation of wearable devices, and soft sensors are the main components of these systems. In this paper, a new sensor design is presented to create stretchable, capacitance-based strain sensors for human motion tracking. This involves the use of stretchable, conductive-knit fabric within the silicone elastomer matrix, as interdigitated electrodes. While conductive fabric creates a secure conductive network for electrodes, a silicone-based matrix provides encapsulation and dimensional-stability to the structure. During the benchtop characterization, sensors show linear output, i.e., R2 = 0.997, with high response time, i.e., 50 ms, and high resolution, i.e., 1.36%. Finally, movement of the knee joint during the different scenarios was successfully recorded.

  5. Strain measurement in concrete using embedded carbon roving-based sensors

    International Nuclear Information System (INIS)

    Quadflieg, Till; Gries, Thomas; Stolyarov, Oleg


    This paper presents the results of the application of carbon rovings as strain sensors for measuring the strain in concrete. In this work, three types of electrically conductive carbon roving with different characteristics were used. The possibility of using carbon rovings as a strain sensor is demonstrated via measurements in tensile and four point bending tests. The experimental setups and methods for measuring the electrical resistance of carbon roving in the roving and concrete are described. The results of the characterization of the electrical behavior as a function of strain of carbon rovings and concrete are presented and discussed. The obtained results indicate that the strain range of carbon rovings optimally corresponds to the strain range of concrete. This characteristic behavior makes the carbon rovings well suited for the use as strain sensors. A good correlation has been found between the electrical resistance-strain curve of the carbon roving and the measurements in the concrete.

  6. Evaluating a slope-stability model for shallow rain-induced landslides using gage and satellite data (United States)

    Yatheendradas, S.; Kirschbaum, D.; Baum, Rex L.; Godt, Jonathan W.


    Improving prediction of landslide early warning systems requires accurate estimation of the conditions that trigger slope failures. This study tested a slope-stability model for shallow rainfall-induced landslides by utilizing rainfall information from gauge and satellite records. We used the TRIGRS model (Transient Rainfall Infiltration and Grid-based Regional Slope-stability analysis) for simulating the evolution of the factor of safety due to rainfall infiltration. Using a spatial subset of a well-characterized digital landscape from an earlier study, we considered shallow failure on a slope adjoining an urban transportation roadway near the Seattle area in Washington, USA.We ran the TRIGRS model using high-quality rain gage and satellite-based rainfall data from the Tropical Rainfall Measuring Mission (TRMM). Preliminary results with parameterized soil depth values suggest that the steeper slope values in this spatial domain have factor of safety values that are extremely close to the failure limit within an extremely narrow range of values, providing multiple false alarms. When the soil depths were constrained using a back analysis procedure to ensure that slopes were stable under initial condtions, the model accurately predicted the timing and location of the landslide observation without false alarms over time for gage rain data. The TRMM satellite rainfall data did not show adequately retreived rainfall peak magnitudes and accumulation over the study period, and as a result failed to predict the landslide event. These preliminary results indicate that more accurate and higher-resolution rain data (e.g., the upcoming Global Precipitation Measurement (GPM) mission) are required to provide accurate and reliable landslide predictions in ungaged basins.

  7. Longitudinally Jointed Edge-wise Compression Honeycomb Composite Sandwich Coupon Testing and FE Analysis: Three Methods of Strain Measurement, and Comparison (United States)

    Farrokh, Babak; AbdulRahim, Nur Aida; Segal, Ken; Fan, Terry; Jones, Justin; Hodges, Ken; Mashni, Noah; Garg, Naman; Sang, Alex; Gifford, Dawn; hide


    Three means (i.e., typical foil strain gages, fiber optic sensors, and a digital image correlation (DIC) system) were implemented to measure strains on the back and front surfaces of a longitudinally jointed curved test article subjected to edge-wise compression testing, at NASA Goddard Space Flight Center, according to ASTM C364. The Pre-test finite element analysis (FEA) was conducted to assess ultimate failure load and predict strain distribution pattern throughout the test coupon. The predicted strain pattern contours were then utilized as guidelines for installing the strain measurement instrumentations. The strain gages and fiber optic sensors were bonded on the specimen at locations with nearly the same strain values, as close as possible to each other, so that, comparisons between the measured strains by strain gages and fiber optic sensors, as well as the DIC system are justified. The test article was loaded to failure (at approximately 38 kips), at the strain value of approximately 10,000mu epsilon As a part of this study, the validity of the measured strains by fiber optic sensors is examined against the strain gage and DIC data, and also will be compared with FEA predictions.

  8. Internships and UNAVCO: Training the Future Geoscience Workforce Through the NSF GAGE Facility (United States)

    Morris, A. R.; MacPherson-Krutsky, C. C.; Charlevoix, D. J.; Bartel, B. A.


    Facilities are uniquely positioned to both serve a broad, national audience and provide unique workforce experience to students and recent graduates. Intentional efforts dedicated to broadening participation in the future geoscience workforce at the NSF GAGE (Geodesy Advancing Geosciences and EarthScope) Facility operated by UNAVCO, are designed to meet the needs of the next generation of students and professionals. As a university-governed consortium facilitating research and education in the geosciences, UNAVCO is well-situated to both prepare students for geoscience technical careers and advanced research positions. Since 1998, UNAVCO has offered over 165 student assistant or intern positions including engineering, data services, education and outreach, and business support. UNAVCO offers three formal programs: the UNAVCO Student Internship Program (USIP), Research Experiences in Solid Earth Science for Students (RESESS), and the Geo-Launchpad (GLP) internship program. Interns range from community college students up through graduate students and recent Masters graduates. USIP interns gain real-world work experience in a professional setting, collaborate with teams toward a common mission, and contribute their knowledge, skills, and abilities to the UNAVCO community. RESESS interns conduct authentic research with a scientist in the Front Range area as well as participate in a structured professional development series. GLP students are in their first 2 years of higher education and work alongside UNAVCO technical staff gaining valuable work experience and insight into the logistics of supporting scientific research. UNAVCO's efforts in preparing the next generation of scientists largely focuses on increasing diversity in the geosciences, whether continuing academic studies or moving into the workforce. To date, well over half of our interns and student assistants come from backgrounds historically underrepresented in the geosciences. Over 80% of former interns

  9. Comparison of DNA-based techniques for differentiation of production strains of ale and lager brewing yeast. (United States)

    Kopecká, J; Němec, M; Matoulková, D


    Brewing yeasts are classified into two species-Saccharomyces pastorianus and Saccharomyces cerevisiae. Most of the brewing yeast strains are natural interspecies hybrids typically polyploids and their identification is thus often difficult giving heterogenous results according to the method used. We performed genetic characterization of a set of the brewing yeast strains coming from several yeast culture collections by combination of various DNA-based techniques. The aim of this study was to select a method for species-specific identification of yeast and discrimination of yeast strains according to their technological classification. A group of 40 yeast strains were characterized using PCR-RFLP analysis of ITS-5·8S, NTS, HIS4 and COX2 genes, multiplex PCR, RAPD-PCR of genomic DNA, mtDNA-RFLP and electrophoretic karyotyping. Reliable differentiation of yeast to the species level was achieved by PCR-RFLP of HIS4 gene. Numerical analysis of the obtained RAPD-fingerprints and karyotype revealed species-specific clustering corresponding with the technological classification of the strains. Taxonomic position and partial hybrid nature of strains were verified by multiplex PCR. Differentiation among species using the PCR-RFLP of ITS-5·8S and NTS region was shown to be unreliable. Karyotyping and RFLP of mitochondrial DNA evinced small inaccuracies in strain categorization. PCR-RFLP of HIS4 gene and RAPD-PCR of genomic DNA are reliable and suitable methods for fast identification of yeast strains. RAPD-PCR with primer 21 is a fast and reliable method applicable for differentiation of brewing yeasts with only 35% similarity of fingerprint profile between the two main technological groups (ale and lager) of brewing strains. It was proved that PCR-RFLP method of HIS4 gene enables precise discrimination among three technologically important Saccharomyces species. Differentiation of brewing yeast to the strain level can be achieved using the RAPD-PCR technique. © 2016 The

  10. Effect of uniaxial strain on the tunnel magnetoresistance of T-shaped graphene nanoribbon based spin-valve (United States)

    Fouladi, A. Ahmadi


    We theoretically investigated the spin-dependent transport through a T-shaped graphene nanoribbon (TsGNR) based spin-valve consisting of armchair graphene sandwiched between two semi-infinite ferromagnetic armchair graphene nanoribbon leads in the presence of an applied uniaxial strain. Based on a tight-binding model and standard nonequilibrium Green's function technique, it is demonstrated that the tunnel magnetoresistance (TMR) for the system can be increased about 98% by tuning the uniaxial strain. Our results show that the absolute values of TMR around the zero bias voltage for compressive strain are larger than tensile strain. In addition, the TMR of the system can be nicely controlled by GNR width.

  11. Comparison of physically based constitutive models characterizing armor steel over wide temperature and strain rate ranges

    International Nuclear Information System (INIS)

    Xu, Zejian; Huang, Fenglei


    Both descriptive and predictive capabilities of five physically based constitutive models (PB, NNL, ZA, VA, and RK) are investigated and compared systematically, in characterizing plastic behavior of the 603 steel at temperatures ranging from 288 to 873 K, and strain rates ranging from 0.001 to 4500 s −1 . Determination of the constitutive parameters is introduced in detail for each model. Validities of the established models are checked by strain rate jump tests performed under different loading conditions. The results show that the RK and NNL models have better performance in the description of material behavior, especially the work-hardening effect, while the PB and VA models predict better. The inconsistency that is observed between the capabilities of description and prediction of the models indicates the existence of the minimum number of required fitting data, reflecting the degree of a model's requirement for basic data in parameter calibration. It is also found that the description capability of a model is dependent to a large extent on both its form and the number of its constitutive parameters, while the precision of prediction relies largely on the performance of description. In the selection of constitutive models, the experimental data and the constitutive models should be considered synthetically to obtain a better efficiency in material behavior characterization

  12. Design of Stress-Strain Measuring System for Bulldozing Plate Based on Virtual Instrument Technology

    International Nuclear Information System (INIS)

    Xu, S C; Li, J Q; Zhang, R


    Soil is a kind of discrete, multiphase compound that is composed of soil particles, liquid and air. When soil is disturbed by bulldozing plate, the mechanical behavior of the soil will become very complex. Based on the law of action and reaction, the dynamic mechanical behavior of disturbed soil was indirectly analyzed by measuring and studying the forces on the bulldozing plate by soil currently, so a stress-strain virtual measuring system for bulldozing plate, which was designed by the graphical programming language DASYLab, was used to measure the horizontal force Fz acting on the bulldozing plate. In addition, during the course of design, the experimental complexities and the interferential factors influencing on signal logging were analyzed when bulldozing plate worked, so the anti-jamming methods of hardware and software technology were adopted correlatively. In the end, the horizontal force Fz was analyzed with Error Theory, the result shown that the quantificational analysis of Fz were identical to the qualitative results of soil well, and the error of the whole test system is under 5 percent, so the tress-strain virtual measuring system was stable and credible

  13. Geometry of X-ray based measurement of residual strain at desired penetration depth

    Energy Technology Data Exchange (ETDEWEB)

    Morawiec, A. [Polish Academy of Sciences, Institute of Metallurgy and Materials Science, Krakow (Poland)


    X-ray based measurement of residual lattice strains at chosen penetration depth is one of the methods for investigating strain inhomogeneities in near-surface layers of polycrystalline materials. The measurement relies on determining shifts of Bragg peaks for various directions of the scattering vector with respect to the specimen. At each of these directions, to reach a given the penetration depth, a proper specimen orientation is required. The task of determining such orientations, albeit elementary, is quite intricate. The existing literature describes only partial solutions with unspecified domains of application, which fail if applied to beyond the domains. Therefore, geometric aspects of the measurement are analyzed in details. Explicit bounds on measurement parameters are given. The equation fundamental for the procedure is solved with respect to specimen orientations. For a given direction of the scattering vector, there are generally four different specimen orientations leading to the same penetration depth. This simple fact (overlooked in previous analyses) can be used for improving reliability of measurement results. Analytical formulas for goniometer angles representing these orientations are provided. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. MBE growth of Topological Isolators based on strained semi-metallic HgCdTe layers (United States)

    Grendysa, J.; Tomaka, G.; Sliz, P.; Becker, C. R.; Trzyna, M.; Wojnarowska-Nowak, R.; Bobko, E.; Sheregii, E. M.


    Particularities of Molecular Beam Epitaxial (MBE) technology for the growth of Topological Insulators (TI) based on the semi-metal Hg1-xCdx Te are presented. A series of strained layers grown on GaAs substrates with a composition close to the 3D Dirac point were studied. The composition of the layers was verified by means of the position of the E1 maximum in optical reflectivity in the visible region. The surface morphology was determined via atomic force and electron microscopy. Magneto-transport measurements show quantized Hall resistance curves and Shubnikov de Hass oscillations (up to 50 K). It has been demonstrated that a well-developed MBE technology enables one to grow strained Hg1-xCdx Te layers on GaAs/CdTe substrates with a well-defined composition near the 3D Dirac point and consequently allows one to produce a 3D topological Dirac semimetal - 3D analogy of graphene - for future applications.

  15. Creation of the Probiotic Consortium on the Base of Strains of Bifidobacterium spp.

    Directory of Open Access Journals (Sweden)

    Kozhakhmetov, S. S.


    Full Text Available Nowadays, a widespread circulation of disbiotic conditions among the population of all ages in Kazakhstan requires an active development in industry for both preparations and products with probiotic properties. The gained bacterial isolates, Bifidobacterium adolescentis 180, B. breve 204, B. breve 584 and B. breve 587 were used in our researches and screening showed they possess high probiotic properties. The consortium possesses strong antimicrobial activity to pathogenic and potentially-pathogenic microflora, insulated during disbacteriosis, as well as from vagina and urea. They are able to produce vitamin B12 and also have antimutagenic activity. As a result, the consortium on the base of strains of Bifidobacterium spp. was received, possessing the following advantages: contains live mass of microbial, antagonistically active strains B. breve and B. adolescentis; contains more than 10^9 alive Bifidobacteria; does not contain plasmids, which means that it could not be a carrier of antibiotic stability for Gram-positive receptive pathogenic and potentially-pathogenic microflora.

  16. Flux control-based design of furfural-resistance strains of Saccharomyces cerevisiae for lignocellulosic biorefinery. (United States)

    Unrean, Pornkamol


    We have previously developed a dynamic flux balance analysis of Saccharomyces cerevisiae for elucidation of genome-wide flux response to furfural perturbation (Unrean and Franzen, Biotechnol J 10(8):1248-1258, 2015). Herein, the dynamic flux distributions were analyzed by flux control analysis to identify target overexpressed genes for improved yeast robustness against furfural. The flux control coefficient (FCC) identified overexpressing isocitrate dehydrogenase (IDH1), a rate-controlling flux for ethanol fermentation, and dicarboxylate carrier (DIC1), a limiting flux for cell growth, as keys of furfural-resistance phenotype. Consistent with the model prediction, strain characterization showed 1.2- and 2.0-fold improvement in ethanol synthesis and furfural detoxification rates, respectively, by IDH1 overexpressed mutant compared to the control. DIC1 overexpressed mutant grew at 1.3-fold faster and reduced furfural at 1.4-fold faster than the control under the furfural challenge. This study hence demonstrated the FCC-based approach as an effective tool for guiding the design of robust yeast strains.

  17. Application of Lactobacillus acidophilus (LA 5) strain in fruit-based ice cream. (United States)

    Senanayake, Suraji A; Fernando, Sirimali; Bamunuarachchi, Arthur; Arsekularatne, Mariam


    A study was performed to apply a probiotic strain into fermented ice cream mix with suitable fruit bases to develop a value-added product with a substantial level of viable organisms for a sufficient shelf life. Pure direct vat strain culture of Lactobacillus acidophilus (LA 5) in freeze-dried form was inoculated into a mixture of ice cream, frozen, and the number of viable organisms during frozen storage for a period of time was enumerated, using turbidity measurements with a spectrophotometer. An ice cream sample prepared without the probiotic culture was compared with the test sample for quality, by testing the basic quality parameters for ice cream. Results show a reduction in the over run of the probiotic ice cream compared to the nonprobiotic ice cream. Significantly high level (P ice cream. Significantly low pH level in the probiotic sample may be due to the lactic acid produced by the probiotic culture. No significant difference (P > 0.05) in the fat content in the two types of ice cream was observed. A significantly low level (P ice cream. Results show the presence of a sufficient number of viable organisms in the product for the 10-week period, which would be beneficial to consumers.

  18. Damage Detection Based on Static Strain Responses Using FBG in a Wind Turbine Blade. (United States)

    Tian, Shaohua; Yang, Zhibo; Chen, Xuefeng; Xie, Yong


    The damage detection of a wind turbine blade enables better operation of the turbines, and provides an early alert to the destroyed events of the blade in order to avoid catastrophic losses. A new non-baseline damage detection method based on the Fiber Bragg grating (FBG) in a wind turbine blade is developed in this paper. Firstly, the Chi-square distribution is proven to be an effective damage-sensitive feature which is adopted as the individual information source for the local decision. In order to obtain the global and optimal decision for the damage detection, the feature information fusion (FIF) method is proposed to fuse and optimize information in above individual information sources, and the damage is detected accurately through of the global decision. Then a 13.2 m wind turbine blade with the distributed strain sensor system is adopted to describe the feasibility of the proposed method, and the strain energy method (SEM) is used to describe the advantage of the proposed method. Finally results show that the proposed method can deliver encouraging results of the damage detection in the wind turbine blade.

  19. Perpendicular magnetic tunnel junction with a strained Mn-based nanolayer (United States)

    Suzuki, K. Z.; Ranjbar, R.; Okabayashi, J.; Miura, Y.; Sugihara, A.; Tsuchiura, H.; Mizukami, S.


    A magnetic tunnel junction with a perpendicular magnetic easy-axis (p-MTJ) is a key device for spintronic non-volatile magnetoresistive random access memory (MRAM). Co-Fe-B alloy-based p-MTJs are being developed, although they have a large magnetisation and medium perpendicular magnetic anisotropy (PMA), which make it difficult to apply them to a future dense MRAM. Here, we demonstrate a p-MTJ with an epitaxially strained MnGa nanolayer grown on a unique CoGa buffer material, which exhibits a large PMA of more than 5 Merg/cm3 and magnetisation below 500 emu/cm3 these properties are sufficient for application to advanced MRAM. Although the experimental tunnel magnetoresistance (TMR) ratio is still low, first principles calculations confirm that the strain-induced crystal lattice distortion modifies the band dispersion along the tetragonal c-axis into the fully spin-polarised state; thus, a huge TMR effect can be generated in this p-MTJ.

  20. An Experimental Technique for Developing Intermediate Strain Rates in Ductile Metals (United States)


    detecting small changes is resistance [45]. Figure 2.11 shows a basic strain gage Wheatstone bridge circuit where R1, R2, R3, and R4 are individual resistors ...all of the resistances of the resistors and the strain gage in the bridge circuit are equal such that, R = R1 = R2 = R3 = R4 and the bridge is...piezoelectric material [45]. Figure 2.13 [45] shows a piezo - electric accelerometer configured such that a mass is threaded onto a post above a

  1. Application of the strain energy for fatigue life prediction (LCF) of metals by the energy-based criterion

    International Nuclear Information System (INIS)

    Shahram Shahrooi; Ibrahim Henk Metselaar; Zainul Huda; Ghezavati, H.R.


    Full text: In this study, the plastic strain energy under multiaxial fatigue condition has been calculated in the cyclic plasticity models by the stress-strain hysteresis loops. Then, using the results of these models, the fatigue lives in energy-based fatigue model is predicted and compared to experimental data. Moreover, a weighting factor on shear plastic work is presented to decrease the life factors in the model fatigue. (author)

  2. Complete genome sequence of cyanobacterium Nostoc sp. NIES-3756, a potentially useful strain for phytochrome-based bioengineering. (United States)

    Hirose, Yuu; Fujisawa, Takatomo; Ohtsubo, Yoshiyuki; Katayama, Mitsunori; Misawa, Naomi; Wakazuki, Sachiko; Shimura, Yohei; Nakamura, Yasukazu; Kawachi, Masanobu; Yoshikawa, Hirofumi; Eki, Toshihiko; Kanesaki, Yu


    To explore the diverse photoreceptors of cyanobacteria, we isolated Nostoc sp. strain NIES-3756 from soil at Mimomi-Park, Chiba, Japan, and determined its complete genome sequence. The Genome consists of one chromosome and two plasmids (total 6,987,571 bp containing no gaps). The NIES-3756 strain carries 7 phytochrome and 12 cyanobacteriochrome genes, which will facilitate the studies of phytochrome-based bioengineering. Copyright © 2015. Published by Elsevier B.V.

  3. Molecular beam epitaxy of alternating-strain ZnSe-based multilayer heterostructures for blue-green lasers

    International Nuclear Information System (INIS)

    Ivanov, S.V.; Toropov, A.A.; Sorokin, S.V.; Shubina, T.V.; Il'inskaya, N.D.; Lebedev, A.V.; Sedova, I.V.; Kop'ev, P.S.; Alferov, Zh.I.; Lugauer, H.-J.; Reuscher, G.; Keim, M.; Fischer, F.; Waag, A.; Landwehr, G.


    High-quality ZnSe-based heterostructures are grown by uninterrupted molecular beam epitaxy using the concept of strain compensation and alternating-strain multilayers. To verify the advantages of this technique, optically pumped ZnSSe/ZnCdSe laser structures containing short-period superlattices or multiple quantum wells have been grown and studied. A room-temperature injection laser diode with a BeZnSe/ZnSe superlattice waveguide is described

  4. Photograph-based ergonomic evaluations using the Rapid Office Strain Assessment (ROSA). (United States)

    Liebregts, J; Sonne, M; Potvin, J R


    The Rapid Office Strain Assessment (ROSA) was developed to assess musculoskeletal disorder (MSD) risk factors for computer workstations. This study examined the validity and reliability of remotely conducted, photo-based assessments using ROSA. Twenty-three office workstations were assessed on-site by an ergonomist, and 5 photos were obtained. Photo-based assessments were conducted by three ergonomists. The sensitivity and specificity of the photo-based assessors' ability to correctly classify workstations was 79% and 55%, respectively. The moderate specificity associated with false positive errors committed by the assessors could lead to unnecessary costs to the employer. Error between on-site and photo-based final scores was a considerable ∼2 points on the 10-point ROSA scale (RMSE = 2.3), with a moderate relationship (ρ = 0.33). Interrater reliability ranged from fairly good to excellent (ICC = 0.667-0.856) and was comparable to previous results. Sources of error include the parallax effect, poor estimations of small joint (e.g. hand/wrist) angles, and boundary errors in postural binning. While this method demonstrated potential validity, further improvements should be made with respect to photo-collection and other protocols for remotely-based ROSA assessments. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  5. Calculation of elastic-plastic strain ranges for fatigue analysis based on linear elastic stresses

    International Nuclear Information System (INIS)

    Sauer, G.


    Fatigue analysis requires that the maximum strain ranges be known. These strain ranges are generally computed from linear elastic analysis. The elastic strain ranges are enhanced by a factor K e to obtain the total elastic-plastic strain range. The reliability of the fatigue analysis depends on the quality of this factor. Formulae for calculating the K e factor are proposed. A beam is introduced as a computational model for determining the elastic-plastic strains. The beam is loaded by the elastic stresses of the real structure. The elastic-plastic strains of the beam are compared with the beam's elastic strains. This comparison furnishes explicit expressions for the K e factor. The K e factor is tested by means of seven examples. (orig.)

  6. Cost effective stream-gaging strategies for the Lower Colorado River basin; the Blythe field office operations (United States)

    Moss, Marshall E.; Gilroy, Edward J.


    This report describes the theoretical developments and illustrates the applications of techniques that recently have been assembled to analyze the cost-effectiveness of federally funded stream-gaging activities in support of the Colorado River compact and subsequent adjudications. The cost effectiveness of 19 stream gages in terms of minimizing the sum of the variances of the errors of estimation of annual mean discharge is explored by means of a sequential-search optimization scheme. The search is conducted over a set of decision variables that describes the number of times that each gaging route is traveled in a year. A gage route is defined as the most expeditious circuit that is made from a field office to visit one or more stream gages and return to the office. The error variance is defined as a function of the frequency of visits to a gage by using optimal estimation theory. Currently a minimum of 12 visits per year is made to any gage. By changing to a six-visit minimum, the same total error variance can be attained for the 19 stations with a budget of 10% less than the current one. Other strategies are also explored. (USGS)

  7. Dielectric oil-based polymer actuator for improved thickness strain and breakdown voltage

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Min Sung; Yamamoto, Akio [Dept. of Precision Engineering, School of Engineering, The University of Tokyo, Tokyo (Japan)


    Dielectric elastomer actuators (DEAs) have been increasingly investigated as alternative actuators to conventional ones. However, DEAs suffer from high rates of premature failure. Therefore, this study proposes a dielectric oil-based polymer actuator, also called a Dielectric liquid actuator (DLA), to compensate for the drawbacks of DEAs. DLA was experimentally compared with conventional DEAs. Results showed that DLA successfully prevented thermal runaway at defects in the electrode and excessive thinning of the film, resulting in increased breakdown voltage. Consequently, premature failure was inhibited, and the performance was improved. The breakdown voltages of DLA and DEA were 6000 and 2000 V, respectively, and their maximum thickness strains were 49.5% and 37.5%, respectively.

  8. Dielectric oil-based polymer actuator for improved thickness strain and breakdown voltage

    International Nuclear Information System (INIS)

    Cho, Min Sung; Yamamoto, Akio


    Dielectric elastomer actuators (DEAs) have been increasingly investigated as alternative actuators to conventional ones. However, DEAs suffer from high rates of premature failure. Therefore, this study proposes a dielectric oil-based polymer actuator, also called a Dielectric liquid actuator (DLA), to compensate for the drawbacks of DEAs. DLA was experimentally compared with conventional DEAs. Results showed that DLA successfully prevented thermal runaway at defects in the electrode and excessive thinning of the film, resulting in increased breakdown voltage. Consequently, premature failure was inhibited, and the performance was improved. The breakdown voltages of DLA and DEA were 6000 and 2000 V, respectively, and their maximum thickness strains were 49.5% and 37.5%, respectively

  9. Phase 3 Trial of a Sabin Strain-Based Inactivated Poliovirus Vaccine. (United States)

    Liao, Guoyang; Li, Rongcheng; Li, Changgui; Sun, Mingbo; Jiang, Shude; Li, Yanping; Mo, Zhaojun; Xia, Jielai; Xie, Zhongping; Che, Yanchun; Yang, Jingsi; Yin, Zhifang; Wang, Jianfeng; Chu, Jiayou; Cai, Wei; Zhou, Jian; Wang, Junzhi; Li, Qihan


     The development of a Sabin strain-based inactivated poliovirus vaccine (Sabin-IPV) is imperative to protecting against vaccine-associated paralytic poliomyelitis in developing countries.  In this double-blinded, parallel-group, noninferiority trial, eligible infants aged 60-90 days were randomly assigned in a ratio of 1:1 to receive either 3 doses of Sabin-IPV or Salk strain-based IPV (Salk-IPV) at 30-day intervals and a booster at the age of 18 months. Immunogenicity and safety were assessed on the basis of a protocol.  Of 1438 infants, 1200 eligible infants were recruited and received either Sabin-IPV or Salk-IPV. From the Sabin-IPV and Salk-IPV groups, 570 and 564 infants, respectively, completed the primary immunization and formed the per-protocol population. The seroconversion rates of the participants who received Sabin-IPV were 100%, 94.9%, and 99.0% (types I, II, and III, respectively), and those of the participants who received Salk-IPV were 94.7%, 91.3%, and 97.9% 1 month after the completion of primary immunization. An anamnestic response for poliovirus types I, II, and III was elicited by a booster in both groups. Except in the case of fever, other adverse events were similar between the 2 groups.  The immune response induced by Sabin-IPV was not inferior to that established with Salk-IPV. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail

  10. Strain transfer analysis of optical fiber based sensors embedded in an asphalt pavement structure

    International Nuclear Information System (INIS)

    Wang, Huaping; Xiang, Ping


    Asphalt pavement is vulnerable to random damage, such as cracking and rutting, which can be proactively identified by distributed optical fiber sensing technology. However, due to the material nature of optical fibers, a bare fiber is apt to be damaged during the construction process of pavements. Thus, a protective layer is needed for this application. Unfortunately, part of the strain of the host material is absorbed by the protective layer when transferring the strain to the sensing fiber. To account for the strain transfer error, in this paper a theoretical analysis of the strain transfer of a three-layered general model has been carried out by introducing Goodman’s hypothesis to describe the interfacial shear stress relationship. The model considers the viscoelastic behavior of the host material and protective layer. The effects of one crack in the host material and the sensing length on strain transfer relationship are been discussed. To validate the effectiveness of the strain transfer analysis, a flexible asphalt-mastic packaged distributed optical fiber sensor was designed and tested in a laboratory environment to monitor the distributed strain and appearance of cracks in an asphalt concrete beam at two different temperatures. The experimental results indicated that the developed strain transfer formula can significantly reduce the strain transfer error, and that the asphalt-mastic packaged optical fiber sensor can successfully monitor the distributed strain and identify local cracks. (paper)

  11. Strain transfer analysis of optical fiber based sensors embedded in an asphalt pavement structure (United States)

    Wang, Huaping; Xiang, Ping


    Asphalt pavement is vulnerable to random damage, such as cracking and rutting, which can be proactively identified by distributed optical fiber sensing technology. However, due to the material nature of optical fibers, a bare fiber is apt to be damaged during the construction process of pavements. Thus, a protective layer is needed for this application. Unfortunately, part of the strain of the host material is absorbed by the protective layer when transferring the strain to the sensing fiber. To account for the strain transfer error, in this paper a theoretical analysis of the strain transfer of a three-layered general model has been carried out by introducing Goodman’s hypothesis to describe the interfacial shear stress relationship. The model considers the viscoelastic behavior of the host material and protective layer. The effects of one crack in the host material and the sensing length on strain transfer relationship are been discussed. To validate the effectiveness of the strain transfer analysis, a flexible asphalt-mastic packaged distributed optical fiber sensor was designed and tested in a laboratory environment to monitor the distributed strain and appearance of cracks in an asphalt concrete beam at two different temperatures. The experimental results indicated that the developed strain transfer formula can significantly reduce the strain transfer error, and that the asphalt-mastic packaged optical fiber sensor can successfully monitor the distributed strain and identify local cracks.

  12. High Strain Rate Testing of Welded DOP-26 Iridium

    Energy Technology Data Exchange (ETDEWEB)

    Schneibel, J. H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Miller, R. G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Carmichael, C. A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Fox, E. E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ulrich, G. B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); George, E. P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)


    The iridium alloy DOP-26 is used to produce Clad Vent Set cups that protect the radioactive fuel in radioisotope thermoelectric generators (RTGs) which provide electric power for spacecraft and rovers. In a previous study, the tensile properties of DOP-26 were measured over a wide range of strain rates and temperatures and reported in ORNL/TM-2007/81. While that study established the properties of the base material, the fabrication of the heat sources requires welding, and the mechanical properties of welded DOP-26 have not been extensively characterized in the past. Therefore, this study was undertaken to determine the mechanical properties of DOP-26 specimens containing a transverse weld in the center of their gage sections. Tensile tests were performed at room temperature, 750, 900, and 1090°C and engineering strain rates of 1×10-3 and 10 s-1. Room temperature testing was performed in air, while testing at elevated temperatures was performed in a vacuum better than 1×10-4 Torr. The welded specimens had a significantly higher yield stress, by up to a factor of ~2, than the non-welded base material. The yield stress did not depend on the strain rate except at 1090°C, where it was slightly higher for the faster strain rate. The ultimate tensile stress, on the other hand, was significantly higher for the faster strain rate at temperatures of 750°C and above. At 750°C and above, the specimens deformed at 1×10-3 s-1 showed pronounced necking resulting sometimes in perfect chisel-edge fracture. The specimens deformed at 10 s-1 exhibited this fracture behavior only at the highest test temperature, 1090°C. Fracture occurred usually in the fusion zone of the weld and was, in most cases, primarily intergranular.

  13. Deformation-strain field in Sichuan and its surrounding areas based on GPS data

    Directory of Open Access Journals (Sweden)

    Fuchao Chen


    Full Text Available The strain rate in Sichuan and its surrounding areas, and the activity rate and strain rate in two block boundary fault zones were calculated according to the block movement parameters estimated using the station speed obtained from regional GPS station observation data in these areas for 2009–2011 and GPS continuous station data for 2011–2013. The movement field characteristics in these areas were analyzed with the Sichuan Basin as the reference. Results show that the principal strain rate and maximum shear strain rate of the Bayan Har block were the largest, followed by those of the Sichuan–Yunnan block and Sichuan Basin. The deep normal strain rate in the Longmenshan fault zone was compressive and large over the study period. The normal strain rate in the Xianshuihe fault zone was tensile.

  14. Selection of Yeast Strains for Tequila Fermentation Based on Growth Dynamics in Combined Fructose and Ethanol Media. (United States)

    Aldrete-Tapia, J A; Miranda-Castilleja, D E; Arvizu-Medrano, S M; Hernández-Iturriaga, M


    The high concentration of fructose in agave juice has been associated with reduced ethanol tolerance of commercial yeasts used for tequila production and low fermentation yields. The selection of autochthonous strains, which are better adapted to agave juice, could improve the process. In this study, a 2-step selection process of yeasts isolated from spontaneous fermentations for tequila production was carried out based on analysis of the growth dynamics in combined conditions of high fructose and ethanol. First, yeast isolates (605) were screened to identify strains tolerant to high fructose (20%) and to ethanol (10%), yielding 89 isolates able to grow in both conditions. From the 89 isolates, the growth curves under 8 treatments of combined fructose (from 20% to 5%) and ethanol (from 0% to 10%) were obtained, and the kinetic parameters were analyzed with principal component analysis and k-means clustering. The resulting yeast strain groups corresponded to the fast, medium and slow growers. A second clustering of only the fast growers led to the selection of 3 Saccharomyces strains (199, 230, 231) that were able to grow rapidly in 4 out of the 8 conditions evaluated. This methodology differentiated strains phenotypically and could be further used for strain selection in other processes. A method to select yeast strains for fermentation taking into account the natural differences of yeast isolates. This methodology is based on the cell exposition to combinations of sugar and ethanol, which are the most important stress factors in fermentation. This strategy will help to identify the most tolerant strain that could improve ethanol yield and reduce fermentation time. © 2018 Institute of Food Technologists®.

  15. Strain- and stress-based forming limit curves for DP 590 steel sheet using Marciniak-Kuczynski method (United States)

    Kumar, Gautam; Maji, Kuntal


    This article deals with the prediction of strain-and stress-based forming limit curves for advanced high strength steel DP590 sheet using Marciniak-Kuczynski (M-K) method. Three yield criteria namely Von-Mises, Hill's 48 and Yld2000-2d and two hardening laws i.e., Hollomon power and Swift hardening laws were considered to predict the forming limit curves (FLCs) for DP590 steel sheet. The effects of imperfection factor and initial groove angle on prediction of FLC were also investigated. It was observed that the FLCs shifted upward with the increase of imperfection factor value. The initial groove angle was found to have significant effects on limit strains in the left side of FLC, and insignificant effect for the right side of FLC for certain range of strain paths. The limit strains were calculated at zero groove angle for the right side of FLC, and a critical groove angle was used for the left side of FLC. The numerically predicted FLCs considering the different combinations of yield criteria and hardening laws were compared with the published experimental results of FLCs for DP590 steel sheet. The FLC predicted using the combination of Yld2000-2d yield criterion and swift hardening law was in better coorelation with the experimental data. Stress based forming limit curves (SFLCs) were also calculated from the limiting strain values obtained by M-K model. Theoretically predicted SFLCs were compared with that obtained from the experimental forming limit strains. Stress based forming limit curves were seen to better represent the forming limits of DP590 steel sheet compared to that by strain-based forming limit curves.

  16. HydroCloud: A Web Application for Exploring Stream Gage Data

    Directory of Open Access Journals (Sweden)

    Martin C. Roberge


    Full Text Available HydroCloud ( is a mobile-friendly web application for visually browsing hydrology data from multiple sources. Data providers such as the US Geological Survey (USGS and the German 'Wasserstraßen- und Schifffahrtsverwaltung des Bundes' (WSV currently serve stream discharge data from more than 10,000 stream gages around the world. HydroCloud allows users to plot these data while out in the field, while also providing contextual information such as the current NEXRAD weather imagery or descriptive information about the stream gage and its watershed. Additional features include a chat mechanism for contacting developers, and the use of local storage for saving data.   Funding Statement: This project was supported in part by a grant from the Towson University School of Emerging Technology.

  17. Application of the nuclear gages in dynamic sedimentology for the solid transport study

    International Nuclear Information System (INIS)

    Lamdasni, Y.


    The problems caused by the solid particle transport in rivers, dams, harbors, estuaries and in navigation channels have considerable economical consequences. The technical difficulties met when trying to limit or manage these problems are very important because of lack of knowledge. The nuclear gages and the radioactive tracers can be the measurement and monitoring means which, associated to the conventional techniques, permit to develop strongly the knowledge in the solid transport field. This report gives the modes of solid transport and the problems caused by these transports and exposes the physical properties of the fine sediments and their behavior under the hydrodynamic effects. In the same way, it deals with the theory of the nuclear gages, often applied in dynamic sedimentology and gives some examples of their applications. 29 refs., 35 figs., 5 tabs. (F.M.)

  18. Low Cost Stream Gaging through Analysis of Stage Height Using Digital Photography (United States)

    Mui, C. K.; Royem, A. A.; Walter, M. T.


    Through the middle of the twentieth century, the US was relatively rich in active streamflow gages. Over the past four decades, the number of gages has decreased by approximately 10% (approx. 20 gages a year) and it is likely this trend will continue for the foreseeable future. Not only are streaflow data valuable for water resources planning and management, but they are invaluable for assessing how land use and climate changes are impacting the environment. Affordable, easy-to-use systems need to be developed to enable a wider community to establish and maintain streamflow observation sites. Currently USGS-like gauges cost 30,000 to 50,000 to build and $6,000/year to maintain. We are developing a system that uses digital images in conjunction with MATLAB for image post processing that has the potential to both accurately and cost effectively monitor stream gauge. We explored several different staff gauge designs in conjunction with associated image processing code. The most robust design so far consists of a brightly colored metal staff gauge and and code that allows a point-and-click method for training the image processing code to correctly identify the staff. We ultimately envision a system in which users can upload their images via the Internet and post-processing is done on a remote server, which also collates data and metadata for open-access downloading.

  19. Effect of bismuth surfactant on InP-based highly strained InAs/InGaAs triangular quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Y.; Zhang, Y. G., E-mail:; Chen, X. Y.; Xi, S. P.; Du, B.; Ma, Y. J. [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)


    We report the effect of Bi surfactant on the properties of highly strained InAs/InGaAs triangular quantum wells grown on InP substrates. Reduced surface roughness, improved heterostructure interfaces and enhanced photoluminescence intensity at 2.2 μm are observed by moderate Bi-mediated growth. The nonradiative processes are analysed based on temperature-dependent photoluminescence. It is confirmed that Bi incorporation is insignificant in the samples, whereas excessive Bi flux during the growth results in deteriorated performance. The surfactant effect of Bi is promising to improve InP-based highly strained structures while the excess of Bi flux needs to be avoided.

  20. Lower-energy neutron sources for increasing the sensitivity of nuclear gages for measuring the water content of bulk materials

    International Nuclear Information System (INIS)

    Bailey, S.M.


    The sensitivity of a gage using a nuclear source for measuring the water content of bulk materials, such as plastic concrete, is increased by use of a lithium or fluorine neutron nuclear source. 3 figures

  1. Sequence-based comparative study of classical swine fever virus genogroup 2.2 isolate with pestivirus reference strains. (United States)

    Kumar, Ravi; Rajak, Kaushal Kishor; Chandra, Tribhuwan; Muthuchelvan, Dhanavelu; Saxena, Arpit; Chaudhary, Dheeraj; Kumar, Ajay; Pandey, Awadh Bihari


    This study was undertaken with the aim to compare and establish the genetic relatedness between classical swine fever virus (CSFV) genogroup 2.2 isolate and pestivirus reference strains. The available complete genome sequences of CSFV/IND/UK/LAL-290 strain and other pestivirus reference strains were retrieved from GenBank. The complete genome sequence, complete open reading frame, 5' and 3' non-coding region (NCR) sequences were analyzed and compared with reference pestiviruses strains. Clustal W model in MegAlign program of Lasergene 6.0 software was used for analysis of genetic heterogeneity. Phylogenetic analysis was carried out using MEGA 6.06 software package. The complete genome sequence alignment of CSFV/IND/UK/LAL-290 isolate and reference pestivirus strains showed 58.9-72% identities at the nucleotide level and 50.3-76.9% at amino acid level. Sequence homology of 5' and 3' NCRs was found to be 64.1-82.3% and 22.9-71.4%, respectively. In phylogenetic analysis, overall tree topology was found similar irrespective of sequences used in this study; however, whole genome phylogeny of pestivirus formed two main clusters, which further distinguished into the monophyletic clade of each pestivirus species. CSFV/IND/UK/LAL-290 isolate placed with the CSFV Eystrup strain in the same clade with close proximity to border disease virus and Aydin strains. CSFV/IND/UK/LAL-290 exhibited the analogous genomic organization to those of all reference pestivirus strains. Based on sequence identity and phylogenetic analysis, the isolate showed close homology to Aydin/04-TR virus and distantly related to Bungowannah virus.

  2. Integrating a logarithmic-strain based hyper-elastic formulation into a three-field mixed finite element formulation to deal with incompressibility in finite-strain elasto-plasticity

    International Nuclear Information System (INIS)

    Dina Al Akhrass; Bruchon, Julien; Drapier, Sylvain; Fayolle, Sebastien


    This paper deals with the treatment of incompressibility in solid mechanics in finite-strain elasto-plasticity. A finite-strain model proposed by Miehe, Apel and Lambrecht, which is based on a logarithmic strain measure and its work-conjugate stress tensor is chosen. Its main interest is that it allows for the adoption of standard constitutive models established in a small-strain framework. This model is extended to take into account the plastic incompressibility constraint intrinsically. In that purpose, an extension of this model to a three-field mixed finite element formulation is proposed, involving displacements, a strain variable and pressure as nodal variables with respect to standard finite element. Numerical examples of finite-strain problems are presented to assess the performance of the formulation. To conclude, an industrial case for which the classical under-integrated elements fail is considered. (authors)

  3. Improving Streamflow Simulation in Gaged and Ungaged Areas Using a Multi-Model Synthesis Combined with Remotely-Sensed Data and Estimates of Uncertainty (United States)

    Lafontaine, J.; Hay, L.


    The United States Geological Survey (USGS) has developed a National Hydrologic Model (NHM) to support coordinated, comprehensive and consistent hydrologic model development, and facilitate the application of hydrologic simulations within the conterminous United States (CONUS). More than 1,700 gaged watersheds across the CONUS were modeled to test the feasibility of improving streamflow simulations in gaged and ungaged watersheds by linking statistically- and physically-based hydrologic models with remotely-sensed data products (i.e. - snow water equivalent) and estimates of uncertainty. Initially, the physically-based models were calibrated to measured streamflow data to provide a baseline for comparison. As many stream reaches in the CONUS are either not gaged, or are substantially impacted by water use or flow regulation, ancillary information must be used to determine reasonable parameter estimations for streamflow simulations. In addition, not all ancillary datasets are appropriate for application to all parts of the CONUS (e.g. - snow water equivalent in the southeastern U.S., where snow is a rarity). As it is not expected that any one data product or model simulation will be sufficient for representing hydrologic behavior across the entire CONUS, a systematic evaluation of which data products improve simulations of streamflow for various regions across the CONUS was performed. The resulting portfolio of calibration strategies can be used to guide selection of an appropriate combination of simulated and measured information for model development and calibration at a given location of interest. In addition, these calibration strategies have been developed to be flexible so that new data products or simulated information can be assimilated. This analysis provides a foundation to understand how well models work when streamflow data is either not available or is limited and could be used to further inform hydrologic model parameter development for ungaged areas.

  4. Nonlinear behavior of capacitive micro-beams based on strain gradient theory

    International Nuclear Information System (INIS)

    Fathalilou, Mohammad; Sadeghi, Morteza; Rezazadeh, Ghader


    This paper studies the size dependent behavior of materials in MEMS structures. This behavior becomes noticeable for a structure when the characteristic size such as thickness or diameter is close to its internal length-scale parameter and is insignificant for the high ratio of the characteristic size to the length-scale parameter, which is the case of the silicon base micro-beams. However, in some types of micro-beams like gold or nickel bases, the size dependent effect cannot be overlooked. In such cases, ignoring this behavior in modeling will lead to incorrect results. Some previous researchers have applied classic beam theory on their models and imposed a considerable hypothetical value of residual stress to match their theoretical results with the experimental ones. The equilibrium positions or fixed points of the gold and nickel micro-beams are obtained and shown that for a given DC voltage, there is a considerable difference between the obtained fixed points using classic beam theory, modified couple stress theory, and modified strain gradient theory. In addition, it is shown that the calculated static and dynamic pull-in voltages using higher order theories are much closer to the experimental results and are higher several times than those obtained by classic beam theory.

  5. Nonlinear fiber-optic strain sensor based on four-wave mixing in microstructured optical fiber

    DEFF Research Database (Denmark)

    Gu, Bobo; Yuan, Scott Wu; Frosz, Michael H.


    We demonstrate a nonlinear fiber-optic strain sensor, which uses the shifts of four-wave mixing Stokes and anti-Stokes peaks caused by the strain-induced changes in the structure and refractive index of a microstructured optical fiber. The sensor thus uses the inherent nonlinearity of the fiber a...

  6. Comprehensive comparison of macro-strain mode and displacement mode based on different sensing technologies (United States)

    Hong, Wan; Zhang, Jian; Wu, Gang; Wu, Zhishen


    A comprehensive comparison of macro-strain mode and displacement mode obtained from distributed macro-strain sensing and high-density point sensing (such as accelerometers) technologies is presented in this paper. Theoretical derivation reveals that displacement mode shape from accelerometers and modal macro-strain from distributed macro-strain sensors can be converted into each other. However, it is realized that displacement mode shape as global behavior of a structure can still be calculated with high-precision from modal macro-strain considering measurement errors in practical monitoring, whereas modal macro-strain can hardly be accurately achieved from displacement mode shape when signals are corrupted with noise in practical monitoring. Simulation and experiment results show that the calculated displacement mode shapes are very close to the actual ones even if the noise level reaches 5%. Meanwhile, damage index using measured modal macro-strain is still effective when the measurements are corrupted with 5% noise which is reliable for damage detection in practical monitoring. Calculating modal macro-strain from noise-polluted displacement mode shape will cause an unacceptable error if the noise level reaches only 0.5%, which has been verified in the simulation.

  7. Whole genome sequencing-based characterization of extensively drug resistant (XDR) strains of Mycobacterium tuberculosis from Pakistan

    KAUST Repository

    Hasan, Zahra; Ali, Asho; McNerney, Ruth; Mallard, Kim; Hill-Cawthorne, Grant A.; Coll, Francesc; Nair, Mridul; Pain, Arnab; Clark, Taane G.; Hasan, Rumina


    Objectives: The global increase in drug resistance in Mycobacterium tuberculosis (MTB) strains increases the focus on improved molecular diagnostics for MTB. Extensively drug-resistant (XDR) - TB is caused by MTB strains resistant to rifampicin, isoniazid, fluoroquinolone and aminoglycoside antibiotics. Resistance to anti-tuberculous drugs has been associated with single nucleotide polymorphisms (SNPs), in particular MTB genes. However, there is regional variation between MTB lineages and the SNPs associated with resistance. Therefore, there is a need to identify common resistance conferring SNPs so that effective molecular-based diagnostic tests for MTB can be developed. This study investigated used whole genome sequencing (WGS) to characterize 37 XDR MTB isolates from Pakistan and investigated SNPs related to drug resistance. Methods: XDR-TB strains were selected. DNA was extracted from MTB strains, and samples underwent WGS with 76-base-paired end fragment sizes using Illumina paired end HiSeq2000 technology. Raw sequence data were mapped uniquely to H37Rv reference genome. The mappings allowed SNPs and small indels to be called using SAMtools/BCFtools. Results: This study found that in all XDR strains, rifampicin resistance was attributable to SNPs in the rpoB RDR region. Isoniazid resistance-associated mutations were primarily related to katG codon 315 followed by inhA S94A. Fluoroquinolone resistance was attributable to gyrA 91-94 codons in most strains, while one did not have SNPs in either gyrA or gyrB. Aminoglycoside resistance was mostly associated with SNPs in rrs, except in 6 strains. Ethambutol resistant strains had embB codon 306 mutations, but many strains did not have this present. The SNPs were compared with those present in commercial assays such as LiPA Hain MDRTBsl, and the sensitivity of the assays for these strains was evaluated. Conclusions: If common drug resistance associated with SNPs evaluated the concordance between phenotypic and

  8. Whole genome sequencing-based characterization of extensively drug resistant (XDR) strains of Mycobacterium tuberculosis from Pakistan

    KAUST Repository

    Hasan, Zahra


    Objectives: The global increase in drug resistance in Mycobacterium tuberculosis (MTB) strains increases the focus on improved molecular diagnostics for MTB. Extensively drug-resistant (XDR) - TB is caused by MTB strains resistant to rifampicin, isoniazid, fluoroquinolone and aminoglycoside antibiotics. Resistance to anti-tuberculous drugs has been associated with single nucleotide polymorphisms (SNPs), in particular MTB genes. However, there is regional variation between MTB lineages and the SNPs associated with resistance. Therefore, there is a need to identify common resistance conferring SNPs so that effective molecular-based diagnostic tests for MTB can be developed. This study investigated used whole genome sequencing (WGS) to characterize 37 XDR MTB isolates from Pakistan and investigated SNPs related to drug resistance. Methods: XDR-TB strains were selected. DNA was extracted from MTB strains, and samples underwent WGS with 76-base-paired end fragment sizes using Illumina paired end HiSeq2000 technology. Raw sequence data were mapped uniquely to H37Rv reference genome. The mappings allowed SNPs and small indels to be called using SAMtools/BCFtools. Results: This study found that in all XDR strains, rifampicin resistance was attributable to SNPs in the rpoB RDR region. Isoniazid resistance-associated mutations were primarily related to katG codon 315 followed by inhA S94A. Fluoroquinolone resistance was attributable to gyrA 91-94 codons in most strains, while one did not have SNPs in either gyrA or gyrB. Aminoglycoside resistance was mostly associated with SNPs in rrs, except in 6 strains. Ethambutol resistant strains had embB codon 306 mutations, but many strains did not have this present. The SNPs were compared with those present in commercial assays such as LiPA Hain MDRTBsl, and the sensitivity of the assays for these strains was evaluated. Conclusions: If common drug resistance associated with SNPs evaluated the concordance between phenotypic and

  9. A comparison of EBSD based strain indicators for the study of Fe-3Si steel subjected to cyclic loading

    Energy Technology Data Exchange (ETDEWEB)

    Schayes, Claire [Université Lille 1 sciences et technologies, UMET – UMR CNRS 8207/ENSCL/Université de Lille, team Métallurgie Physique et Génie des Matériaux, Bâtiment C6, 59655 Villeneuve d' Ascq (France); Valeo Engine Electrical Systems, 2 Rue André Boulle, 94046 Créteil (France); Bouquerel, Jérémie, E-mail: [Université Lille 1 sciences et technologies, UMET – UMR CNRS 8207/ENSCL/Université de Lille, team Métallurgie Physique et Génie des Matériaux, Bâtiment C6, 59655 Villeneuve d' Ascq (France); Vogt, Jean-Bernard [Université Lille 1 sciences et technologies, UMET – UMR CNRS 8207/ENSCL/Université de Lille, team Métallurgie Physique et Génie des Matériaux, Bâtiment C6, 59655 Villeneuve d' Ascq (France); Palleschi, Frédéric [Valeo Engine Electrical Systems, 2 Rue André Boulle, 94046 Créteil (France); Zaefferer, Stefan [Max-Planck-Institut für Eisenforschung, Abteilung Mikrostrukturphysik und Umformtechnik, Max-Planck-Strasse 1, 40237 Düsseldorf (Germany)


    The current work aims at proposing an EBSD-based indicator for fatigue damage of a Fe-3Si steel. At the same time direct observation of dislocation structures is provided by electron channelling contrast imaging (ECCI). The investigation consisted in processing the EBSD data from patterns collected on specimen subjected to low cycle fatigue. It revealed two different regimes depending on the applied total strain variation which is explained by the identification of the dislocations structures and their evolution. At low strain variation, strain accommodation occurs by planar glide of dislocations uniformly distributed throughout the grains. No misorientation evolution is observed. At higher strain variation, the vein-channel structure is observed within the grain and the wall-channel structure in the vicinity of grain boundaries. The misorientation between these two dislocation structures is evaluated at about 0.7° which is detected by the EBSD analyses and explains the increase of the different misorientation based criteria. The EBSD study enables also the prediction of crack initiation mode. Finally, this study points out the limits of the EBSD technique as no misorientation evolution is detected at small strain variation. Indeed, the lattice distortion is too weak to be detected by conventional EBSD. - Highlights: • Microstructure investigation of the fatigue behaviour of an iron-silicon steel • Use of cECCI to investigate the fatigue dislocations structures • Characterisation of local plastic accommodation through EBSD misorientation criteria.

  10. 3D printed high performance strain sensors for high temperature applications (United States)

    Rahman, Md Taibur; Moser, Russell; Zbib, Hussein M.; Ramana, C. V.; Panat, Rahul


    Realization of high temperature physical measurement sensors, which are needed in many of the current and emerging technologies, is challenging due to the degradation of their electrical stability by drift currents, material oxidation, thermal strain, and creep. In this paper, for the first time, we demonstrate that 3D printed sensors show a metamaterial-like behavior, resulting in superior performance such as high sensitivity, low thermal strain, and enhanced thermal stability. The sensors were fabricated using silver (Ag) nanoparticles (NPs), using an advanced Aerosol Jet based additive printing method followed by thermal sintering. The sensors were tested under cyclic strain up to a temperature of 500 °C and showed a gauge factor of 3.15 ± 0.086, which is about 57% higher than that of those available commercially. The sensor thermal strain was also an order of magnitude lower than that of commercial gages for operation up to a temperature of 500 °C. An analytical model was developed to account for the enhanced performance of such printed sensors based on enhanced lateral contraction of the NP films due to the porosity, a behavior akin to cellular metamaterials. The results demonstrate the potential of 3D printing technology as a pathway to realize highly stable and high-performance sensors for high temperature applications.

  11. Fatigue strain mapping via digital image correlation for Ni-based superalloys: The role of thermal activation on cube slip

    International Nuclear Information System (INIS)

    Mello, Alberto W.; Nicolas, Andrea; Sangid, Michael D.


    A deformation mechanism map for a Ni-based superalloy is presented during cyclic loading at low (300 °C), intermediate (550 °C), and high (700 °C) temperatures for low (0.7%) and high (1.0%) applied strain amplitudes. Strain mapping is performed via digital image correlation (DIC) during interrupted fatigue experiments at elevated temperatures at 1, 10, 100 and 1000 cycles, for each specified loading and temperature condition. The DIC measurements are performed in a scanning electron microscope, which allows high-resolution measurements of heterogeneous slip events and a vacuum environment to ensure stability of the speckle pattern for DIC at high temperatures. The cumulative fatigue experiments show that the slip bands are present in the first cycle and intensify with number of cycles; resulting in highly localized strain accumulation. The strain mapping results are combined with microstructure characterization via electron backscatter diffraction. The combination of crystal orientations and high-resolution strain measurements was used to determine the active slip planes. At low temperatures, slip bands follow the {111} octahedral planes. However, as temperature increases, both the {111} octahedral and {100} cubic slip planes accommodate strain. The activation of cubic slip via cross-slip within the ordered intermetallic γ’ phase has been well documented in Ni-based superalloys and is generally accepted as the mechanism responsible for the anomalous yield phenomenon. The results in this paper represent an important quantifiable study of cubic slip system activity at the mesoscale in polycrystalline γ-γ’ Ni-based superalloys, which is a key advancement to calibrate the thermal activation components of polycrystalline deformation models.

  12. Fatigue strain mapping via digital image correlation for Ni-based superalloys: The role of thermal activation on cube slip

    Energy Technology Data Exchange (ETDEWEB)

    Mello, Alberto W.; Nicolas, Andrea; Sangid, Michael D., E-mail:


    A deformation mechanism map for a Ni-based superalloy is presented during cyclic loading at low (300 °C), intermediate (550 °C), and high (700 °C) temperatures for low (0.7%) and high (1.0%) applied strain amplitudes. Strain mapping is performed via digital image correlation (DIC) during interrupted fatigue experiments at elevated temperatures at 1, 10, 100 and 1000 cycles, for each specified loading and temperature condition. The DIC measurements are performed in a scanning electron microscope, which allows high-resolution measurements of heterogeneous slip events and a vacuum environment to ensure stability of the speckle pattern for DIC at high temperatures. The cumulative fatigue experiments show that the slip bands are present in the first cycle and intensify with number of cycles; resulting in highly localized strain accumulation. The strain mapping results are combined with microstructure characterization via electron backscatter diffraction. The combination of crystal orientations and high-resolution strain measurements was used to determine the active slip planes. At low temperatures, slip bands follow the {111} octahedral planes. However, as temperature increases, both the {111} octahedral and {100} cubic slip planes accommodate strain. The activation of cubic slip via cross-slip within the ordered intermetallic γ’ phase has been well documented in Ni-based superalloys and is generally accepted as the mechanism responsible for the anomalous yield phenomenon. The results in this paper represent an important quantifiable study of cubic slip system activity at the mesoscale in polycrystalline γ-γ’ Ni-based superalloys, which is a key advancement to calibrate the thermal activation components of polycrystalline deformation models.

  13. Ultrathin epidermal strain sensor based on an elastomer nanosheet with an inkjet-printed conductive polymer (United States)

    Tetsu, Yuma; Yamagishi, Kento; Kato, Akira; Matsumoto, Yuya; Tsukune, Mariko; Kobayashi, Yo; Fujie, Masakatsu G.; Takeoka, Shinji; Fujie, Toshinori


    To minimize the interference that skin-contact strain sensors cause natural skin deformation, physical conformability to the epidermal structure is critical. Here, we developed an ultrathin strain sensor made from poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) inkjet-printed on a polystyrene-polybutadiene-polystyrene (SBS) nanosheet. The sensor, whose total thickness and gauge factor were ˜1 µm and 0.73 ± 0.10, respectively, deeply conformed to the epidermal structure and successfully detected the small skin strain (˜2%) while interfering minimally with the natural deformation of the skin. Such an epidermal strain sensor will open a new avenue for precisely detecting the motion of human skin and artificial soft-robotic skin.

  14. SERS-based detection methods for screening of genetically modified bacterial strains

    DEFF Research Database (Denmark)

    Morelli, Lidia

    factories vary largely, including industrial production of valuable compounds for biofuels, polymer synthesis and food, cosmetic and pharmaceutical industry. The improvement of computational and biochemical tools has revolutionized the synthesis of novel modified microbial strains, opening up new......The importance of metabolic engineering has been growing over the last decades, establishing the use of genetically modified microbial strains for overproduction of metabolites at industrial scale as an innovative, convenient and biosustainable method. Nowadays, application areas of microbial...

  15. Microstructurally Based Prediction of High Strain Failure Modes in Crystalline Solids (United States)


    interfaces in hcp– fcc systems subjected to high strain-rate deformation and fracture modes, Journal of Materials Research, (8 2015): 0. doi: 10.1557/jmr...rupture • Comparison and validation with experimental observations/ measurements • New dislocation-density crystalline plasticity that accounts for...relationships between coherent interfaces in hcp– fcc systems subjected to high strain-rate deformation and fracture modes, Journal of Materials Research, Vol. 30

  16. Dynamic model updating based on strain mode shape and natural frequency using hybrid pattern search technique (United States)

    Guo, Ning; Yang, Zhichun; Wang, Le; Ouyang, Yan; Zhang, Xinping


    Aiming at providing a precise dynamic structural finite element (FE) model for dynamic strength evaluation in addition to dynamic analysis. A dynamic FE model updating method is presented to correct the uncertain parameters of the FE model of a structure using strain mode shapes and natural frequencies. The strain mode shape, which is sensitive to local changes in structure, is used instead of the displacement mode for enhancing model updating. The coordinate strain modal assurance criterion is developed to evaluate the correlation level at each coordinate over the experimental and the analytical strain mode shapes. Moreover, the natural frequencies which provide the global information of the structure are used to guarantee the accuracy of modal properties of the global model. Then, the weighted summation of the natural frequency residual and the coordinate strain modal assurance criterion residual is used as the objective function in the proposed dynamic FE model updating procedure. The hybrid genetic/pattern-search optimization algorithm is adopted to perform the dynamic FE model updating procedure. Numerical simulation and model updating experiment for a clamped-clamped beam are performed to validate the feasibility and effectiveness of the present method. The results show that the proposed method can be used to update the uncertain parameters with good robustness. And the updated dynamic FE model of the beam structure, which can correctly predict both the natural frequencies and the local dynamic strains, is reliable for the following dynamic analysis and dynamic strength evaluation.

  17. Highly Sensitive and Very Stretchable Strain Sensor Based on a Rubbery Semiconductor. (United States)

    Kim, Hae-Jin; Thukral, Anish; Yu, Cunjiang


    There is a growing interest in developing stretchable strain sensors to quantify the large mechanical deformation and strain associated with the activities for a wide range of species, such as humans, machines, and robots. Here, we report a novel stretchable strain sensor entirely in a rubber format by using a solution-processed rubbery semiconductor as the sensing material to achieve high sensitivity, large mechanical strain tolerance, and hysteresis-less and highly linear responses. Specifically, the rubbery semiconductor exploits π-π stacked poly(3-hexylthiophene-2,5-diyl) nanofibrils (P3HT-NFs) percolated in silicone elastomer of poly(dimethylsiloxane) to yield semiconducting nanocomposite with a large mechanical stretchability, although P3HT is a well-known nonstretchable semiconductor. The fabricated strain sensors exhibit reliable and reversible sensing capability, high gauge factor (gauge factor = 32), high linearity (R 2 > 0.996), and low hysteresis (degree of hysteresis wearable smart gloves. Systematic investigations in the materials design and synthesis, sensor fabrication and characterization, and mechanical analysis reveal the key fundamental and application aspects of the highly sensitive and very stretchable strain sensors entirely from rubbers.

  18. Surface strain rate colour map of the Tatra Mountains region (Slovakia based on GNSS data

    Directory of Open Access Journals (Sweden)

    Bednárik Martin


    Full Text Available The surface deformation of the Tatra Mountains region in Western Carpathians can nowadays be studied directly thanks to precise geodetic measurements using the GNSS. The strain or stress tensor field is, however, a rather complex “data structure” difficult to present legibly and with sufficient resolution in the form of a classical map. A novel and promising approach to the solution of this problem is coding the three principal strain or stress values into the three colour channels (red, green, blue of an RGB colour. In our previous study, the colour depended on the stress tensor shape descriptors. In the current study, the adapted colouring scheme uses a subset of shape descriptors common to stress and strain, which differ only in the scaling factor. In this manner, we generate the colour map of the surface strain rate field, where the colour of each grid point carries the information about the shape of the strain rate tensor at that point. The resulting strain rate colour map can be displayed simultaneously with the map of the faults or elevations and be easily checked for the data or interpolation method errors and incompatibility with the geophysical and geological expectations.

  19. A 3D finite-strain-based constitutive model for shape memory alloys accounting for thermomechanical coupling and martensite reorientation (United States)

    Wang, Jun; Moumni, Ziad; Zhang, Weihong; Xu, Yingjie; Zaki, Wael


    The paper presents a finite-strain constitutive model for shape memory alloys (SMAs) that accounts for thermomechanical coupling and martensite reorientation. The finite-strain formulation is based on a two-tier, multiplicative decomposition of the deformation gradient into thermal, elastic, and inelastic parts, where the inelastic deformation is further split into phase transformation and martensite reorientation components. A time-discrete formulation of the constitutive equations is proposed and a numerical integration algorithm is presented featuring proper symmetrization of the tensor variables and explicit formulation of the material and spatial tangent operators involved. The algorithm is used for finite element analysis of SMA components subjected to various loading conditions, including uniaxial, non-proportional, isothermal and adiabatic loading cases. The analysis is carried out using the FEA software Abaqus by means of a user-defined material subroutine, which is then utilized to simulate a SMA archwire undergoing large strains and rotations.

  20. Multiwavelength Raman-fiber-laser-based long-distance remote sensor for simultaneous measurement of strain and temperature. (United States)

    Han, Young-Geun; Tran, T V A; Kim, Sang-Hyuck; Lee, Sang Bae


    We propose a simple and flexible multiwavelength Raman-fiber-laser-based long-distance remote-sensing scheme for simultaneous measurement of strain and temperature by use of fiber Bragg gratings. By combining two uniform fiber Bragg gratings with a tunable chirped fiber grating, we readily achieve simultaneous two-channel sensing probes with a high extinction ratio of more than approximately 50 dB over a 50-km distance. When strain and temperature are applied, lasing wavelength separation and shift occur, respectively, since the two uniform fiber Bragg gratings have identical material composition and different cladding diameters. This allows simultaneous measurement of strain and temperature for long-distance sensing applications of more than 50 km.

  1. The impact of elastic and plastic strain on relaxation and crystallization of Pd–Ni–P-based bulk metallic glasses

    International Nuclear Information System (INIS)

    Mitrofanov, Yu.P.; Peterlechner, M.; Binkowski, I.; Zadorozhnyy, M.Yu.; Golovin, I.S.; Divinski, S.V.; Wilde, G.


    The effects of deformation and subsequent heat treatment on the low-temperature heat capacity, enthalpy relaxation rate and mechanical losses of two Pd–Ni–P-based bulk metallic glasses of slightly different compositions and different thermal stabilities have been investigated. It was found that the crystallization temperatures decreased significantly with imposed strain and the effect was more pronounced for the alloy with a higher thermal stability. The boson heat capacity peak increases with increasing strain in both alloys. However, after annealing treatments above room temperature, it relaxes to a lower enthalpy state as compared to that of the as-quenched state for the alloy with a lower thermal stability. The existence of two counteracting processes that might be related to different shear band structures within one homogeneously deformed sample is suggested. These results agree with the internal friction data, which indicate different regimes of mechanical damping as a function of the strain amplitude, while the critical amplitude of a transition between the regimes depends on the imposed strain. The results are interpreted within the energy landscape approach and advocate that the composition-dependent local atomic configurations affect significantly the response of the glass to an applied strain

  2. Displacement gage

    International Nuclear Information System (INIS)

    Tanner, D.E.


    This invention concerns a position indicator for detecting and indicating the position of a remotely placed component mobile about an axis, such as valves located inside vessels and pipelines under pressure physically inaccessible when the reactor is working. A light source is channelled and aligned on the spindle of the valve wheel. It reaches a fixed reflector secured to this spindle. The reflected light is received on a light collector of which each collector composed of a photodiode sends back the signal by optical fibre to the display area. The position of the wheel is therefore determined by the lighting of one of the optical fibres [fr

  3. Application of AFINCH as a tool for evaluating the effects of streamflow-gaging-network size and composition on the accuracy and precision of streamflow estimates at ungaged locations in the southeast Lake Michigan hydrologic subregion (United States)

    Koltun, G.F.; Holtschlag, David J.


    Bootstrapping techniques employing random subsampling were used with the AFINCH (Analysis of Flows In Networks of CHannels) model to gain insights into the effects of variation in streamflow-gaging-network size and composition on the accuracy and precision of streamflow estimates at ungaged locations in the 0405 (Southeast Lake Michigan) hydrologic subregion. AFINCH uses stepwise-regression techniques to estimate monthly water yields from catchments based on geospatial-climate and land-cover data in combination with available streamflow and water-use data. Calculations are performed on a hydrologic-subregion scale for each catchment and stream reach contained in a National Hydrography Dataset Plus (NHDPlus) subregion. Water yields from contributing catchments are multiplied by catchment areas and resulting flow values are accumulated to compute streamflows in stream reaches which are referred to as flow lines. AFINCH imposes constraints on water yields to ensure that observed streamflows are conserved at gaged locations.  Data from the 0405 hydrologic subregion (referred to as Southeast Lake Michigan) were used for the analyses. Daily streamflow data were measured in the subregion for 1 or more years at a total of 75 streamflow-gaging stations during the analysis period which spanned water years 1971–2003. The number of streamflow gages in operation each year during the analysis period ranged from 42 to 56 and averaged 47. Six sets (one set for each censoring level), each composed of 30 random subsets of the 75 streamflow gages, were created by censoring (removing) approximately 10, 20, 30, 40, 50, and 75 percent of the streamflow gages (the actual percentage of operating streamflow gages censored for each set varied from year to year, and within the year from subset to subset, but averaged approximately the indicated percentages).Streamflow estimates for six flow lines each were aggregated by censoring level, and results were analyzed to assess (a) how the

  4. Strain-based plastic instability acceptance criteria for ferritic steel safety class 1 nuclear components under level D

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Su; Lee, Han Sang; Kim, Yun Jae [Dept. of Mechanical Engineering, Korea University, Seoul (Korea, Republic of); Kim, Jong Sung [Dept. of Mechanical Engineering, Sunchon National University, Suncheon (Korea, Republic of); Kim, Jin Won [Dept. of Nuclear Engineering, Chosun University, Gwangju (Korea, Republic of)


    This paper proposes strain-based acceptance criteria for assessing plastic instability of the safety class 1 nuclear components made of ferritic steel during level D service loads. The strain-based criteria were proposed with two approaches: (1) a section average approach and (2) a critical location approach. Both approaches were based on the damage initiation point corresponding to the maximum load-carrying capability point instead of the fracture point via tensile tests and finite element analysis (FEA) for the notched specimen under uni-axial tensile loading. The two proposed criteria were reviewed from the viewpoint of design practice and philosophy to select a more appropriate criterion. As a result of the review, it was found that the section average approach is more appropriate than the critical location approach from the viewpoint of design practice and philosophy. Finally, the criterion based on the section average approach was applied to a simplified reactor pressure vessel (RPV) outlet nozzle subject to SSE loads. The application shows that the strain-based acceptance criteria can consider cumulative damages caused by the sequential loads unlike the stress-based acceptance criteria and can reduce the over conservatism of the stress-based acceptance criteria, which often occurs for level D service loads.

  5. Strain-based plastic instability acceptance criteria for ferritic steel safety class 1 nuclear components under level D

    International Nuclear Information System (INIS)

    Kim, Ji Su; Lee, Han Sang; Kim, Yun Jae; Kim, Jong Sung; Kim, Jin Won


    This paper proposes strain-based acceptance criteria for assessing plastic instability of the safety class 1 nuclear components made of ferritic steel during level D service loads. The strain-based criteria were proposed with two approaches: (1) a section average approach and (2) a critical location approach. Both approaches were based on the damage initiation point corresponding to the maximum load-carrying capability point instead of the fracture point via tensile tests and finite element analysis (FEA) for the notched specimen under uni-axial tensile loading. The two proposed criteria were reviewed from the viewpoint of design practice and philosophy to select a more appropriate criterion. As a result of the review, it was found that the section average approach is more appropriate than the critical location approach from the viewpoint of design practice and philosophy. Finally, the criterion based on the section average approach was applied to a simplified reactor pressure vessel (RPV) outlet nozzle subject to SSE loads. The application shows that the strain-based acceptance criteria can consider cumulative damages caused by the sequential loads unlike the stress-based acceptance criteria and can reduce the over conservatism of the stress-based acceptance criteria, which often occurs for level D service loads.

  6. Energy harvesting from vibration of Timoshenko nanobeam under base excitation considering flexoelectric and elastic strain gradient effects (United States)

    Managheb, S. A. M.; Ziaei-Rad, S.; Tikani, R.


    The coupling between polarization and strain gradients is called flexoelectricity. This phenomenon exists in all dielectrics with any symmetry. In this paper, energy harvesting from a Timoshenko beam is studied by considering the flexoelectric and strain gradient effects. General governing equations and related boundary conditions are derived using Hamilton's principle. The flexoelectric effects are defined by gradients of normal and shear strains which lead to a more general model. The developed model also covers the classical Timoshenko beam theory by ignoring the flexoelectric effect. Based on the developed model, flexoelectricity effect on dielectric beams and energy harvesting from cantilever beam under harmonic base excitation is investigated. A parametric study was conducted to evaluate the effects of flexoelectric coefficients, strain gradient constants, base acceleration and the attaching tip mass on the energy harvested from a cantilever Timoshenko beam. Results show that the flexoelectricity has a significant effect on the energy harvester performance, especially in submicron and nano scales. In addition, this effect makes the beam to behave softer than before and also it changes the harvester first resonance frequency. The present study provides guidance for flexoelectric nano-beam analysis and a method to evaluate the performance of energy harvester in nano-dielectric devices.

  7. Evolution of phase structure and giant strain at low driving fields in Bi-based lead-free incipient piezoelectrics

    International Nuclear Information System (INIS)

    Maqbool, Adnan; Hussain, Ali; Malik, Rizwan Ahmed; Rahman, Jamil Ur; Zaman, Arif; Song, Tae Kwon; Kim, Won-Jeong; Kim, Myong-Ho


    Graphical abstract: - Highlights: • Nb-doped BNBT–SZ ceramics were prepared by conventional solid state method. • A giant normalized strain of 825 pm/V at 4 kV/mm was achieved. • A large strain of 0.20% triggered at a relatively low field of 3 kV/mm. • Highest strain obtained in BNT-based ceramics at such a low driving field. • Ferroelectric to ergodic-relaxor phase transition occurred with Nb-doping. - Abstract: Lead-free 0.99[(Bi 0.5 Na 0.5 ) 0.935 Ba 0.065 Ti (1–x) Nb x O 3 ]–0.01SrZrO 3 (BNBTNb100x–SZ, with Nb100x = 0–1) ceramics were prepared by the conventional mixed oxide route. X-ray diffraction and Raman scattering was utilized for the structural evolution of Nb-modified BNBT–SZ ceramics at average and short-scale localized structure. Temperature dependent dielectric properties showed ferroelectric–ergodic relaxor (FE–ER) transition in Nb-modified BNBT–SZ ceramics by producing a significant disruption of the long-range FE order. A giant normalized strain of 825 pm/V at 4 kV/mm was achieved at Nb1.0. Interestingly, at a relatively low applied field of 3 kV/mm, the Nb0.75 sample displayed a large electric field-induced strain (EFIS) response of 0.20%, which is highest value obtained in non-textured lead-free BNT-based ceramics at such low driving field. The structural distortion induced by doping and electric poling is correlated with the dielectric, ferroelectric and EFIS response, and the evolution of giant strain was ascribed to reversible field induced phase transition from ER–FE phase

  8. Effect of plastic strain on elastic-plastic fracture toughness of SM490 carbon steel. Assessment by stress-based criterion for ductile crack initiation

    International Nuclear Information System (INIS)

    Kamaya, Masayuki


    Although the plastic strain induced in materials increases the mechanical strength, it may reduce the fracture toughness. In this study, the change in fracture toughness of SM490 carbon steel due to pre-straining was investigated using a stress-based criterion for ductile crack initiation. The specimens with blunt notch of various radiuses were used in addition to those with conventional fatigue pre-cracking. The degree of applied plastic strain was 5%, 10% or 20%. The fracture toughness was largest when the induced plastic strain was 5%, although it decreased for the plastic strains of 10% and 20%. The stress and strain distributions near the crack tip of fracture toughness test specimens was investigated by elastic-plastic finite element analyses using a well-correlated stress-strain curve for large strain. It was shown that the critical condition at the onset of the ductile crack was better correlated with the equivalent stress than the plastic strain at the crack tip. By using the stress-based criterion, which was represented by the equivalent stress and stress triaxiality, the change in the fracture toughness due to pre-straining could be reasonably explained. Based on these results, it was concluded that the stress-based criterion should be used for predicting the ductile crack initiation. (author)

  9. Geographical markers for Saccharomyces cerevisiae strains with similar technological origins domesticated for rice-based ethnic fermented beverages production in North East India. (United States)

    Jeyaram, Kumaraswamy; Tamang, Jyoti Prakash; Capece, Angela; Romano, Patrizia


    Autochthonous strains of Saccharomyces cerevisiae from traditional starters used for the production of rice-based ethnic fermented beverage in North East India were examined for their genetic polymorphism using mitochondrial DNA-RFLP and electrophoretic karyotyping. Mitochondrial DNA-RFLP analysis of S. cerevisiae strains with similar technological origins from hamei starter of Manipur and marcha starter of Sikkim revealed widely separated clusters based on their geographical origin. Electrophoretic karyotyping showed high polymorphism amongst the hamei strains within similar mitochondrial DNA-RFLP cluster and one unique karyotype of marcha strain was widely distributed in the Sikkim-Himalayan region. We conceptualized the possibility of separate domestication events for hamei strains in Manipur (located in the Indo-Burma biodiversity hotspot) and marcha strains in Sikkim (located in Himalayan biodiversity hotspot), as a consequence of less homogeneity in the genomic structure between these two groups, their clear separation being based on geographical origin, but not on technological origin and low strain level diversity within each group. The molecular markers developed based on HinfI-mtDNA-RFLP profile and the chromosomal doublets in chromosome VIII position of Sikkim-Himalayan strains could be effectively used as geographical markers for authenticating the above starter strains and differentiating them from other commercial strains.

  10. Beam model for seismic analysis of complex shear wall structure based on the strain energy equivalence

    International Nuclear Information System (INIS)

    Reddy, G.R.; Mahajan, S.C.; Suzuki, Kohei


    A nuclear reactor building structure consists of shear walls with complex geometry, beams and columns. The complexity of the structure is explained in the section Introduction. Seismic analysis of the complex reactor building structure using the continuum mechanics approach may produce good results but this method is very difficult to apply. Hence, the finite element approach is found to be an useful technique for solving the dynamic equations of the reactor building structure. In this approach, the model which uses finite elements such as brick, plate and shell elements may produce accurate results. However, this model also poses some difficulties which are explained in the section Modeling Techniques. Therefore, seismic analysis of complex structures is generally carried out using a lumped mass beam model. This model is preferred because of its simplicity and economy. Nevertheless, mathematical modeling of a shear wall structure as a beam requires specialized skill and a thorough understanding of the structure. For accurate seismic analysis, it is necessary to model more realistically the stiffness, mass and damping. In linear seismic analysis, modeling of the mass and damping may pose few problems compared to modeling the stiffness. When used to represent a complex structure, the stiffness of the beam is directly related to the shear wall section properties such as area, shear area and moment of inertia. Various beam models which are classified based on the method of stiffness evaluation are also explained under the section Modeling Techniques. In the section Case Studies the accuracy and simplicity of the beam models are explained. Among various beam models, the one which evaluates the stiffness using strain energy equivalence proves to be the simplest and most accurate method for modeling the complex shear wall structure. (author)

  11. High-resolution spatiotemporal strain mapping reveals non-uniform deformation in micropatterned elastomers (United States)

    Aksoy, B.; Rehman, A.; Bayraktar, H.; Alaca, B. E.


    Micropatterns are generated on a vast selection of polymeric substrates for various applications ranging from stretchable electronics to cellular mechanobiological systems. When these patterned substrates are exposed to external loading, strain field is primarily affected by the presence of microfabricated structures and similarly by fabrication-related defects. The capturing of such nonhomogeneous strain fields is of utmost importance in cases where study of the mechanical behavior with a high spatial resolution is necessary. Image-based non-contact strain measurement techniques are favorable and have recently been extended to scanning tunneling microscope and scanning electron microscope images for the characterization of mechanical properties of metallic materials, e.g. steel and aluminum, at the microscale. A similar real-time analysis of strain heterogeneity in elastomers is yet to be achieved during the entire loading sequence. The available measurement methods for polymeric materials mostly depend on cross-head displacement or precalibrated strain values. Thus, they suffer either from the lack of any real-time analysis, spatiotemporal distribution or high resolution in addition to a combination of these factors. In this work, these challenges are addressed by integrating a tensile stretcher with an inverted optical microscope and developing a subpixel particle tracking algorithm. As a proof of concept, the patterns with a critical dimension of 200 µm are generated on polydimethylsiloxane substrates and strain distribution in the vicinity of the patterns is captured with a high spatiotemporal resolution. In the field of strain measurement, there is always a tradeoff between minimum measurable strain value and spatial resolution. Current noncontact techniques on elastomers can deliver a strain resolution of 0.001% over a minimum length of 5 cm. More importantly, inhomogeneities within this quite large region cannot be captured. The proposed technique can

  12. High-resolution spatiotemporal strain mapping reveals non-uniform deformation in micropatterned elastomers

    International Nuclear Information System (INIS)

    Aksoy, B; Alaca, B E; Rehman, A; Bayraktar, H


    Micropatterns are generated on a vast selection of polymeric substrates for various applications ranging from stretchable electronics to cellular mechanobiological systems. When these patterned substrates are exposed to external loading, strain field is primarily affected by the presence of microfabricated structures and similarly by fabrication-related defects. The capturing of such nonhomogeneous strain fields is of utmost importance in cases where study of the mechanical behavior with a high spatial resolution is necessary. Image-based non-contact strain measurement techniques are favorable and have recently been extended to scanning tunneling microscope and scanning electron microscope images for the characterization of mechanical properties of metallic materials, e.g. steel and aluminum, at the microscale. A similar real-time analysis of strain heterogeneity in elastomers is yet to be achieved during the entire loading sequence. The available measurement methods for polymeric materials mostly depend on cross-head displacement or precalibrated strain values. Thus, they suffer either from the lack of any real-time analysis, spatiotemporal distribution or high resolution in addition to a combination of these factors. In this work, these challenges are addressed by integrating a tensile stretcher with an inverted optical microscope and developing a subpixel particle tracking algorithm. As a proof of concept, the patterns with a critical dimension of 200 µ m are generated on polydimethylsiloxane substrates and strain distribution in the vicinity of the patterns is captured with a high spatiotemporal resolution. In the field of strain measurement, there is always a tradeoff between minimum measurable strain value and spatial resolution. Current noncontact techniques on elastomers can deliver a strain resolution of 0.001% over a minimum length of 5 cm. More importantly, inhomogeneities within this quite large region cannot be captured. The proposed technique can

  13. Lignocellulose-Adapted Endo-Cellulase Producing Streptomyces Strains for Bioconversion of Cellulose-Based Materials. (United States)

    Ventorino, Valeria; Ionata, Elena; Birolo, Leila; Montella, Salvatore; Marcolongo, Loredana; de Chiaro, Addolorata; Espresso, Francesco; Faraco, Vincenza; Pepe, Olimpia


    Twenty-four Actinobacteria strains, isolated from Arundo donax, Eucalyptus camaldulensis and Populus nigra biomass during natural biodegradation and with potential enzymatic activities specific for the degradation of lignocellulosic materials, were identified by a polyphasic approach. All strains belonged to the genus Streptomyces ( S .) and in particular, the most highly represented species was Streptomyces argenteolus representing 50% of strains, while 8 strains were identified as Streptomyces flavogriseus (synonym S. flavovirens ) and Streptomyces fimicarius (synonyms Streptomyces acrimycini, Streptomyces baarnensis, Streptomyces caviscabies , and Streptomyces flavofuscus ), and the other four strains belonged to the species Streptomyces drozdowiczii, Streptomyces rubrogriseus, Streptomyces albolongus , and Streptomyces ambofaciens . Moreover, all Streptomyces strains, tested for endo and exo-cellulase, cellobiase, xylanase, pectinase, ligninase, peroxidase, and laccase activities using qualitative and semi-quantitative methods on solid growth medium, exhibited multiple enzymatic activities (from three to six). The 24 strains were further screened for endo-cellulase activity in liquid growth medium and the four best endo-cellulase producers ( S. argenteolus AE58P, S. argenteolus AE710A, S. argenteolus AE82P, and S. argenteolus AP51A) were subjected to partial characterization and their enzymatic crude extracts adopted to perform saccharification experiments on A. donax pretreated biomass. The degree of cellulose and xylan hydrolysis was evaluated by determining the kinetics of glucose and xylose release during 72 h incubation at 50°C from the pretreated biomass in the presence of cellulose degrading enzymes (cellulase and β-glucosidase) and xylan related activities (xylanase and β-xylosidase). The experiments were carried out utilizing the endo-cellulase activities from the selected S. argenteolus strains supplemented with commercial β-gucosidase and

  14. Design of bridge crane girder strain acquisition system based on virtual instrument

    Directory of Open Access Journals (Sweden)

    Wenxue LIU

    Full Text Available Girder is an important part of the bridge crane, which is also the main force element. In order to prevent accidents, it is necessary to collect the bridge crane girder stress data to analyse the fatigue life. This paper constructs a bridge crane girder strain acquisition system. The hardware system consists of sensors, connectors, data acquisition cards, wireless data transmission groups, POE power and host computer. The software system consists of NI MAX to interface with the computer's NI hardware and software resources,and LabVIEW programming to display and storage the girder strain data. Through this system, positions and working days strain data acquisition for the 50/10 t bridge crane girder gets the key positions strain data. The results show that the girder strain data acquisition system runs stably, channel signals of acquisition task transmit accurately, and the terminal data stores competely, meeting the detection requirements, which provides an important data support for the subsequent fatigue analysis and accurate remaining service life prediction of the crane girder.

  15. RNAseq-based transcriptome comparison of Saccharomyces cerevisiae strains isolated from diverse fermentative environments. (United States)

    Ibáñez, Clara; Pérez-Torrado, Roberto; Morard, Miguel; Toft, Christina; Barrio, Eladio; Querol, Amparo


    Transcriptome analyses play a central role in unraveling the complexity of gene expression regulation in Saccharomyces cerevisiae. This species, one of the most important microorganisms for humans given its industrial applications, shows an astonishing degree of genetic and phenotypic variability among different strains adapted to specific environments. In order to gain novel insights into the Saccharomyces cerevisiae biology of strains adapted to different fermentative environments, we analyzed the whole transcriptome of three strains isolated from wine, flor wine or mezcal fermentations. An RNA-seq transcriptome comparison of the different yeasts in the samples obtained during synthetic must fermentation highlighted the differences observed in the genes that encode mannoproteins, and in those involved in aroma, sugar transport, glycerol and alcohol metabolism, which are important under alcoholic fermentation conditions. These differences were also observed in the physiology of the strains after mannoprotein and aroma determinations. This study offers an essential foundation for understanding how gene expression variations contribute to the fermentation differences of the strains adapted to unequal fermentative environments. Such knowledge is crucial to make improvements in fermentation processes and to define targets for the genetic improvement or selection of wine yeasts. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Improved incorporation of strain gradient elasticity in the flexoelectricity based energy harvesting from nanobeams (United States)

    Zhou, Yarong; Yang, Xu; Pan, Dongmei; Wang, Binglei


    Flexoelectricity, the coupling of strain gradient and polarization, exists in all the dielectric materials and numerous models have been proposed to study this mechanism. However, the contribution of strain gradient elasticity has typically been underestimated. In this work, inspired by the one-length scale parameter model developed by Deng et al. [19], we incorporate three length-scale parameters to carefully capture the contribution of the purely mechanical strain gradients on flexoelectricity. This three-parameter model is more flexible and could be applied to investigate the flexoelectricity in a wide range of complicated deformations. Accordingly, we carry out our analysis by studying a dielectric nanobeam under different boundary conditions. We show that the strain gradient elasticity and flexoelectricity have apparent size effects and significant influence on the electromechanical response. In particular, the strain gradient effects could significantly reduce the energy efficiency, indicating their importance and necessity. This work may be helpful in understanding the mechanism of flexoelectricity at the nanoscale and sheds light on the flexoelectricity energy harvesting.

  17. Passive wireless strain measurement based upon the Villari effect and giant magnetoresistance (United States)

    Windl, Roman; Bruckner, Florian; Abert, Claas; Huber, Christian; Vogler, Christoph; Huber, Thomas; Oezelt, Harald; Suess, Dieter


    A passive wireless radio frequency-identification (RFID) stress/strain sensor is presented. Stress is transformed into a change of magnetic field by utilizing an amorphous metal ribbon. This magnetic field change is measured by a giant magnetoresistance magnetic field sensor and converted into a digital value with a RFID chip for wireless access. Standard metal foil strain gauges have a gauge factor GF from around 2 to 5 and suffer from the disadvantage of a physically connected power supply and measurement equipment. For the presented sensor, a strain range of -10 μm/m to 190 μm/m results in a linear sensor response, a gauge factor of GF ≈ 245, and a detectivity of 4.10 nm/m 1/√{Hz } . The detectivity of the presented sensor is similar to the detectivity of a reference metal foil strain gauge. Due to low power consumption and easy signal analysis, this sensor is well suited for long term strain measurement inside closed spaces. RFID adds features like multiple tag detection, wireless passive operation and a user data storage.

  18. Gage for gas flow measurement especially in gas-suction pipes

    International Nuclear Information System (INIS)

    Renner, K.; Stegmanns, W.


    The gage utilizes the differential pressure given by a differential pressure producer to generate, in a bypass, a partial gas flow measured by means of a direct-reading anemometer of windmill type. The partial gas flow is generated between pressure pick-up openings in the gas-suction pipe in front of a venturi insert and pressure pick-up openings at the bottleneck of the venturi insert. The reading of the anemometer is proportional to the main gas flow and independent of the variables of state and the properties of the gases to be measured. (RW) [de

  19. Doses of personnel employed in the manufacture of radioisotope thickness gages

    International Nuclear Information System (INIS)

    Kostenetskij, M.I.


    Doses of the personnel of one of the plants manifacturing radioisotope thickness gages of different types are determined. Annual doses to the body protected by shielding screens are low and according to the data of individual dosimetry constitute 5x10 -3 -6x10 -3 J/kg (0.5-0.6 rem). A table of radiation doses to hands obtained during all kind of operations, is given. Measures for the further reduction of radiation doses of the personnel are suggested [ru

  20. Damage identification method for continuous girder bridges based on spatially-distributed long-gauge strain sensing under moving loads (United States)

    Wu, Bitao; Wu, Gang; Yang, Caiqian; He, Yi


    A novel damage identification method for concrete continuous girder bridges based on spatially-distributed long-gauge strain sensing is presented in this paper. First, the variation regularity of the long-gauge strain influence line of continuous girder bridges which changes with the location of vehicles on the bridge is studied. According to this variation regularity, a calculation method for the distribution regularity of the area of long-gauge strain history is investigated. Second, a numerical simulation of damage identification based on the distribution regularity of the area of long-gauge strain history is conducted, and the results indicate that this method is effective for identifying damage and is not affected by the speed, axle number and weight of vehicles. Finally, a real bridge test on a highway is conducted, and the experimental results also show that this method is very effective for identifying damage in continuous girder bridges, and the local element stiffness distribution regularity can be revealed at the same time. This identified information is useful for maintaining of continuous girder bridges on highways.

  1. Model-based methodology to develop the isochronous stress-strain curves for modified 9Cr steels

    International Nuclear Information System (INIS)

    Kim, Woo Gon; Yin, Song Nan; Kim, Sung Ho; Lee, Chan Bock; Jung, Ik Hee


    Since high temperature materials are designed with a target life based on a specified amount of allowable strain and stress, their Isochronous Stress-Strain Curves (ISSC) are needed to avoid an excessive deformation during an intended service life. In this paper, a model-based methodology to develop the isochronous curves for a G91 steel is described. Creep strain-time curves were reviewed for typical high-temperature materials, and Garofalo's model which conforms well to the primary and secondary creep stages was proper for the G91 steel. Procedures to obtain an instantaneous elastic-plastic strain, ε i were given in detail. Also, to accurately determine the P 1 , P 2 and P 3 parameters in the Garofalo's model, a Nonlinear Least Square Fitting (NLSF) method was adopted and useful. The long-term creep curves for the G91 steel can be modeled by the Garofalo's model, and the long-term ISSCs can be developed using the modeled creep curves

  2. Serotyping of Actinobacillus pleuropneumoniae serotype 5 strains using a monoclonal-based polystyrene agglutination test

    DEFF Research Database (Denmark)

    Dubreuil, J.D.; Letellier, A.; Stenbæk, Eva


    A polystyrene agglutination test has been developed for serotyping Actinobacillus pleuropneumoniae serotype 5a and 5b strains. Protein A-coated polystyrene microparticles were sensitized with a murine monoclonal antibody recognizing an epitope on serotype 5 LPS-O chain as shown by SDS-PAGE and We......A polystyrene agglutination test has been developed for serotyping Actinobacillus pleuropneumoniae serotype 5a and 5b strains. Protein A-coated polystyrene microparticles were sensitized with a murine monoclonal antibody recognizing an epitope on serotype 5 LPS-O chain as shown by SDS...... suspension of bacterial cells grown for 18 h. All A, pleuropneumoniae strains had been previously serotyped using standard procedures, The polystyrene agglutination test was rapid (less than 3 min) and easy to perform. Overall a very good correlation (97.3%) with the standard techniques was found...

  3. Probe-based real-time PCR method for multilocus melt typing of Xylella fastidiosa strains. (United States)

    Brady, Jeff A; Faske, Jennifer B; Ator, Rebecca A; Castañeda-Gill, Jessica M; Mitchell, Forrest L


    Epidemiological studies of Pierce's disease (PD) can be confounded by a lack of taxonomic detail on the bacterial causative agent, Xylella fastidiosa (Xf). PD in grape is caused by strains of Xylella fastidiosa subsp. fastidiosa, but is not caused by other subspecies of Xf that typically colonize plants other than grape. Detection assays using ELISA and qPCR are effective at detecting and quantifying Xf presence or absence, but offer no information on Xf subspecies or strain identity. Surveying insects or host plants for Xf by current ELISA or qPCR methods provides only presence/absence and quantity information for any and all Xf subspecies, potentially leading to false assessments of disease threat. This study uses a series of adjacent-hybridizing DNA melt analysis probes that are capable of efficiently discriminating Xf subspecies and strain relationships in rapid real-time PCR reactions. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Welding deformation analysis based on improved equivalent strain method to cover external constraint during cooling stage

    Directory of Open Access Journals (Sweden)

    Tae-Jun Kim


    Full Text Available In the present study, external restraints imposed normal to the plate during the cooling stage were determined to be effective for reduction of the angular distortion of butt-welded or fillet-welded plate. A welding analysis model under external force during the cooling stage was idealized as a prismatic member subjected to pure bending. The external restraint was represented by vertical force on both sides of the work piece and bending stress forms in the transverse direction. The additional bending stress distribution across the plate thickness was reflected in the improved inherent strain model, and a set of inherent strain charts with different levels of bending stress were newly calculated. From an elastic linear FE analysis using the inherent strain values taken from the chart and comparing them with those from a 3D thermal elasto-plastic FE analysis, welding deformation can be calculated.

  5. Strain induced tunable wavelength filters based on flexible polymer waveguide Bragg reflector. (United States)

    Kim, Kyung-Jo; Seo, Jun-Kyu; Oh, Min-Cheol


    A tunable wavelength filter is demonstrated by imposing a strain on a polymeric Bragg reflection waveguide fabricated on a flexible substrate. The highly elastic property of flexible polymer device enables much wider tuning than the silica fiber. To produce a uniform grating pattern on a flexible plastic substrate, a post lift-off process along with an absorbing layer is incorporated. The flexible Bragg reflector shows narrow bandwidth, which is convincing the uniformity of the grating structure fabricated on plastic film. By stretching the flexible polymer device, the Bragg reflection wavelength is tuned continuously up to 45 nm for the maximum strain of 31,690 muepsilon, which is determined by the elastic expansion limit of waveguide polymer. From the linear wavelength shift proportional to the strain, the photoelastic coefficient of the ZPU polymer is found.

  6. Finite element analysis of fatigue crack closure under plane strain state

    International Nuclear Information System (INIS)

    Lee, Hak Joo; Kang, Jae Youn; Song, Ji Ho


    An elastic-plastic finite element analysis of fatigue crack closure is performed for plane strain conditions. The stabilization behavior of crack opening level and the effect of mesh size on the crack opening stress are investigated. In order to obtain a stabilized crack opening level for plane strain conditions, the crack must be advanced through approximately four times the initial monotonic plastic zone. The crack opening load tends to increase with the decrease of mesh size. The mesh size nearly equal to the theoretical plane strain cyclic plastic zone size may provide reasonable numerical results comparable with experimental crack opening data. The crack opening behavior is influenced by the crack growth increment and discontinuous opening behavior is observed. A procedure to predict the most appropriate mesh size for different stress ratio is suggested. Crack opening loads predicted by the FE analysis based on the procedure suggested resulted in good agreement with experimental ones within the error of 5 %. Effect of the distance behind the crack tip on the crack opening load determined by the ASTM compliance offset method based on the load-displacement relation and by the rotational offset method based on the load-differential displacement relation is investigated. Optimal gage location and method to determine the crack opening load is suggested

  7. Recent advances in condition assessment of components based on strain monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Parker, J.D. [University of Wales, Swansea (United Kingdom)


    Service experience indicates that creep cavitation and cracking can develop in components operating at high temperature and pressure. Life optimisation programmes for power generating plant require periodic evaluation of plant condition. Instrumentation to measure component deformation provides information regarding operating practices which lead to excessive loading and data which can be related to damage state. Indeed, even near weldments, where creep cavitation and cracking can develop with low overall strain, significant levels of deformation have been recorded in local regions. Thus, knowledge of strain accumulation allows identification of the factors affecting damage accumulation and provides a basis for predicting remaining life. (orig.) 8 refs.

  8. Recent advances in condition assessment of components based on strain monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Parker, J D [University of Wales, Swansea (United Kingdom)


    Service experience indicates that creep cavitation and cracking can develop in components operating at high temperature and pressure. Life optimisation programmes for power generating plant require periodic evaluation of plant condition. Instrumentation to measure component deformation provides information regarding operating practices which lead to excessive loading and data which can be related to damage state. Indeed, even near weldments, where creep cavitation and cracking can develop with low overall strain, significant levels of deformation have been recorded in local regions. Thus, knowledge of strain accumulation allows identification of the factors affecting damage accumulation and provides a basis for predicting remaining life. (orig.) 8 refs.


    International Nuclear Information System (INIS)

    SHOMAN, A.A.


    Special strains that produce only males are used now for the control of the medfly Ceratitis capitata using the sterile insect technique. The use of these strains has a major impact on the overall efficiency of SIT, by increasing significantly the amount of sterility induced in field population comparing by using bisexual strains. Genetic sexing strains (GSS) are based on the use of male-linked chromosomal translocations which enable selectable marker genes to be linked to the male sex. Two basic components are required in the medfly to construct and adapt a laboratory strain which exhibits genetic sexing properties. The first is Y-auto some translocation strain, which enables male and female pupae to be differentiated on the basis of colour and the second is temperature sensitive lethal (tsl) mutation strain, which enables females to be killed by an increase in ambient temperature

  10. Strain measurements during pressurized thermal shock experiment

    International Nuclear Information System (INIS)

    Tarso Vida Gomes, P. de; Julio Ricardo Barreto Cruz; Tanius Rodrigues Mansur; Denis Henrique Bianchi Scaldaferri; Miguel Mattar Neto


    For the life extension of nuclear power plants, the residual life of most of their components must be evaluated along all their operating time. Concerning the reactor pressure vessel, the pressurized thermal shock (PTS) is a very important event to be considered. For better understanding the effects of this kind of event, tests are made. The approach described here consisted of building a simplified in-scale physical model of the reactor pressure vessel, submitting it to the actual operating temperature and pressure conditions and provoking a thermal shock by means of cold water flow in its external surface. To conduct such test, the Nuclear Technology Development Center (CDTN) has been conducting several studies related to PTS and has also built a laboratory that has made possible the simulation of the PTS loading conditions. Several cracks were produced in the external surface of the reactor pressure vessel model. Strain gages were fixed by means of electrical discharge welding over the cracks regions in both external and internal surfaces. The temperature was monitored in 10 points across the vessel wall. The internal pressure was manually controlled and monitored using a pressure transducer. Two PTS experiments were conducted and this paper presents the strain measurement procedures applied to the reactor pressure vessel model, during the PTS, using strain gages experimental methodology. (authors)

  11. Microfabricated photoplastic cantilever with integrated photoplastic/carbon based piezoresistive strain sensor

    DEFF Research Database (Denmark)

    Gammelgaard, Lauge; Rasmussen, Peter Andreas; Calleja, M.


    We present an SU-8 micrometer sized cantilever strain sensor with an integrated piezoresistor made of a conductive composite of SU-8 polymer and carbon black particles. The composite has been developed using ultrasonic mixing. Cleanroom processing of the polymer composite has been investigated...

  12. Skin-like pressure and strain sensors based on transparent elastic films of carbon nanotubes. (United States)

    Lipomi, Darren J; Vosgueritchian, Michael; Tee, Benjamin C-K; Hellstrom, Sondra L; Lee, Jennifer A; Fox, Courtney H; Bao, Zhenan


    Transparent, elastic conductors are essential components of electronic and optoelectronic devices that facilitate human interaction and biofeedback, such as interactive electronics, implantable medical devices and robotic systems with human-like sensing capabilities. The availability of conducting thin films with these properties could lead to the development of skin-like sensors that stretch reversibly, sense pressure (not just touch), bend into hairpin turns, integrate with collapsible, stretchable and mechanically robust displays and solar cells, and also wrap around non-planar and biological surfaces such as skin and organs, without wrinkling. We report transparent, conducting spray-deposited films of single-walled carbon nanotubes that can be rendered stretchable by applying strain along each axis, and then releasing this strain. This process produces spring-like structures in the nanotubes that accommodate strains of up to 150% and demonstrate conductivities as high as 2,200 S cm(-1) in the stretched state. We also use the nanotube films as electrodes in arrays of transparent, stretchable capacitors, which behave as pressure and strain sensors.

  13. Tattoo-Like Strain Gauges Based on Silicon Nano-Membranes (United States)

    Lu, Nanshu


    This talk reports the in vivo measurement of tissue deformation through adhesive-free, conformable lamination of a tattoo-like elastic strain gauge consisted of piezoresistive silicon nano-membranes strategically integrated with tissue-like elastomeric substrates. The mechanical deformation in soft tissues cannot yet be directly quantified due to the lack of enabling tools. While stiff strain gauges for structural health monitoring have long existed, biological tissues are soft, curvilinear and highly deformable in contrast to civil or aerospace structures. An ultra-thin, ultra-soft, tattoo-like strain gauge that can conform to the convoluted surface of human body and stay attached during locomotion will be able to directly quantify tissue deformation without affecting the mechanical behavior of the tissue. While single crystalline silicon is known to have the highest gauge factor and best elastic response, it is intrinsically stiff and brittle. To achieve strain gauges with high compliance, high stretchability and reasonable sensitivity, single crystalline silicon nano-membranes will be transfer-printed onto polymeric support through carefully engineered stamps. The thickness and length of the Si strip will be chosen according to theoretical and numerical mechanics analysis which takes into account for the tradeoff between stretchability and sensitivity.

  14. Mycobacterium marinum strains can be divided into two distinct types based on genetic diversity and virulence

    NARCIS (Netherlands)

    van der Sar, Astrid M.; Abdallah, Abdallah M.; Sparrius, Marion; Reinders, Erik; Vandenbroucke-Grauls, Christina M. J. E.; Bitter, Wilbert


    Mycobacterium marinum causes a systemic tuberculosis-like disease in a large number of poikilothermic animals and is used as a model for mycobacterial pathogenesis. In the present study, we infected zebra fish (Danio rerio) with different strains of M. marinum to determine the variation in

  15. Strain profiles in ion implanted ceramic polycrystals: An approach based on reciprocal-space crystal selection

    Energy Technology Data Exchange (ETDEWEB)

    Palancher, H., E-mail:; Martin, G.; Fouet, J. [CEA, DEN, DEC, F-13108 Saint Paul lez Durance (France); Goudeau, P. [Institut Pprime, CNRS-Université de Poitiers–ENSMA, SP2MI, F-86360 Chasseneuil (France); Boulle, A. [Science des Procédés Céramiques et Traitements de Surface (SPCTS), CNRS UMR 7315, Centre Européen de la Céramique, 12 rue Atlantis, 87068 Limoges (France); Rieutord, F. [CEA, DSM, INAC, F-38054 Grenoble Cedex 9 (France); Favre-Nicolin, V. [Université Grenoble-Alpes, F-38041 Grenoble, France, Institut Universitaire de France, F-75005 Paris (France); Blanc, N. [Institut NEEL, CNRS-Univ Grenoble Alpes, F-38042 Grenoble (France); Onofri, C. [CEA, DEN, DEC, F-13108 Saint Paul lez Durance (France); CEMES, CNRS UPR 8011, 29 rue Jeanne Marvig, BP 94347, 31055 Toulouse Cedex 4 (France)


    The determination of the state of strain in implanted materials is a key issue in the study of their mechanical stability. Whereas this question is nowadays relatively easily solved in the case of single crystals, it remains a challenging task in the case of polycrystalline materials. In this paper, we take benefit of the intense and parallel beams provided by third generation synchrotron sources combined with a two-dimensional detection system to analyze individual grains in polycrystals, hence obtaining “single crystal-like” data. The feasibility of the approach is demonstrated with implanted UO{sub 2} polycrystals where the in-depth strain profile is extracted for individual grains using numerical simulations of the diffracted signal. The influence of the implantation dose is precisely analyzed for several diffracting planes and grains. This work suggests that, at low fluences, the development of strain is mainly due to ballistic effects with little effect from He ions, independently from the crystallographic orientation. At higher fluences, the evolution of the strain profiles suggests a partial and anisotropic plastic relaxation. With the present approach, robust and reliable structural information can be obtained, even from complex polycrystalline ceramic materials.

  16. Validation Tests of Fiber Optic Strain-Based Operational Shape and Load Measurements (United States)

    Bakalyar, John A.; Jutte, Christine


    Aircraft design has been progressing toward reduced structural weight to improve fuel efficiency, increase performance, and reduce cost. Lightweight aircraft structures are more flexible than conventional designs and require new design considerations. Intelligent sensing allows for enhanced control and monitoring of aircraft, which enables increased structurally efficiency. The NASA Dryden Flight Research Center (DFRC) has developed an instrumentation system and analysis techniques that combine to make distributed structural measurements practical for lightweight vehicles. Dryden's Fiber Optic Strain Sensing (FOSS) technology enables a multitude of lightweight, distributed surface strain measurements. The analysis techniques, referred to as the Displacement Transfer Functions (DTF) and Load Transfer Functions (LTF), use surface strain values to calculate structural deflections and operational loads. The combined system is useful for real-time monitoring of aeroelastic structures, along with many other applications. This paper describes how the capabilities of the measurement system were demonstrated using subscale test articles that represent simple aircraft structures. Empirical FOSS strain data were used within the DTF to calculate the displacement of the article and within the LTF to calculate bending moments due to loads acting on the article. The results of the tests, accuracy of the measurements, and a sensitivity analysis are presented.

  17. Are people living next to mobile phone base stations more strained? Relationship of health concerns, self-estimated distance to base station, and psychological parameters. (United States)

    Augner, Christoph; Hacker, Gerhard W


    Coeval with the expansion of mobile phone technology and the associated obvious presence of mobile phone base stations, some people living close to these masts reported symptoms they attributed to electromagnetic fields (EMF). Public and scientific discussions arose with regard to whether these symptoms were due to EMF or were nocebo effects. The aim of this study was to find out if people who believe that they live close to base stations show psychological or psychobiological differences that would indicate more strain or stress. Furthermore, we wanted to detect the relevant connections linking self-estimated distance between home and the next mobile phone base station (DBS), daily use of mobile phone (MPU), EMF-health concerns, electromagnetic hypersensitivity, and psychological strain parameters. Fifty-seven participants completed standardized and non-standardized questionnaires that focused on the relevant parameters. In addition, saliva samples were used as an indication to determine the psychobiological strain by concentration of alpha-amylase, cortisol, immunoglobulin A (IgA), and substance P. Self-declared base station neighbors (DBS base station neighbors are more strained than others. EMF-related health concerns cannot explain these findings. Further research should identify if actual EMF exposure or other factors are responsible for these results.

  18. Financial strain and cognitive-based smoking processes: The explanatory role of depressive symptoms among adult daily smokers. (United States)

    Robles, Zuzuky; Anjum, Sahar; Garey, Lorra; Kauffman, Brooke Y; Rodríguez-Cano, Rubén; Langdon, Kirsten J; Neighbors, Clayton; Reitzel, Lorraine R; Zvolensky, Michael J


    Little work has focused on the underlying mechanisms that may link financial strain and smoking processes. The current study tested the hypothesis that financial strain would exert an indirect effect on cognitive-based smoking processes via depressive symptoms. Three clinically significant dependent variables linked to the maintenance of smoking were evaluated: negative affect reduction motives, negative mood abstinence expectancies, and perceived barriers for quitting. Participants included 102 adult daily smokers (M age =33.0years, SD=13.60; 35.3% female) recruited from the community to participate in a self-guided (unaided; no psychological or pharmacological intervention) smoking cessation study. Results indicated that depressive symptoms explain, in part, the relation between financial strain and smoking motives for negative affect reduction, negative mood abstinence expectancies, and perceived barriers for quitting. Results indicate that smoking interventions for individuals with high levels of financial strain may potentially benefit from the addition of therapeutic tactics aimed at reducing depression. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Strain Amount Dependent Grain Size and Orientation Developments during Hot Compression of a Polycrystalline Nickel Based Superalloy

    Directory of Open Access Journals (Sweden)

    Guoai He


    Full Text Available Controlling grain size in polycrystalline nickel base superalloy is vital for obtaining required mechanical properties. Typically, a uniform and fine grain size is required throughout forging process to realize the superplastic deformation. Strain amount occupied a dominant position in manipulating the dynamic recrystallization (DRX process and regulating the grain size of the alloy during hot forging. In this article, the high-throughput double cone specimen was introduced to yield wide-range strain in a single sample. Continuous variations of effective strain ranging from 0.23 to 1.65 across the whole sample were achieved after reaching a height reduction of 70%. Grain size is measured to be decreased from the edge to the center of specimen with increase of effective strain. Small misorientation tended to generate near the grain boundaries, which was manifested as piled-up dislocation in micromechanics. After the dislocation density reached a critical value, DRX progress would be initiated at higher deformation region, leading to the refinement of grain size. During this process, the transformations from low angle grain boundaries (LAGBs to high angle grain boundaries (HAGBs and from subgrains to DRX grains are found to occur. After the accomplishment of DRX progress, the neonatal grains are presented as having similar orientation inside the grain boundary.

  20. The effect of strain distribution on microstructural developments during forging in a newly developed nickel base superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Buckingham, R.C. [Institute of Structural Materials, Swansea University, Bay Campus, Fabian Way, Swansea SA1 8EN (United Kingdom); Argyrakis, C.; Hardy, M.C. [Rolls-Royce plc, PO Box 31, Derby DE24 8BJ (United Kingdom); Birosca, S., E-mail: [Institute of Structural Materials, Swansea University, Bay Campus, Fabian Way, Swansea SA1 8EN (United Kingdom)


    In the current study, the effect of strain distribution in a simple forging geometry on the propensity for recrystallization, and its impact on mechanical properties has been investigated in a newly developed experimental nickel-based superalloy. The new alloy was produced via a Powder Metallurgy (PM) route and was subsequently Hot Isostatic Processed (HIP), isothermally forged, and heat treated to produce a coarse grain microstructure with average grain size of 23–32 μm. The alloy was examined by means of Electron Back-Scatter Diffraction (EBSD) to characterise the microstructural features such as grain orientation and morphology, grain boundary characteristics and the identification of potential Prior Particle Boundaries (PPBs) throughout each stage of the processing route. Results at the central region of the cross-section plane parallel to the loading direction showed significant microstructural differences across the forging depth. This microstructural variation was found to be highly dependent on the value of local strain imparted during forging such that areas of low effective strain showed partial recrystallisation and a necklace grain structure was observed following heat treatment. Meanwhile, a fully recrystallised microstructure with no PPBs was observed in the areas of high strain values, in the central region of the forging.

  1. Optimization of protection and calibration of the moisture-density gages troxler

    International Nuclear Information System (INIS)



    The purpose of this work is the implementation of the principle of optimization of the protection and calibration of moisture-density gages TROXLER. The main objectives are the application of radiation protection and the feasibility of a calibration laboratory design. The calibration of density and moisture may confirm the calibration of moisture-density gages TROXLER. The calibration of density consists of the assembly of measurements on three calibration blocks (magnesium, aluminium and magnesium/aluminium) built in the TRACKER. The value of density uncertainty is ±32 Kg.m -3 . The calibration of moisture is carried out on two calibration blocks (magnesium and magnesium/polyethylene)The value of moisture uncertainty is ±16 Kg.m -3 . The design of the laboratory returns to the dose limitation. The laboratory is designed mainly wall out of ordinary concrete, a good attenuator of the gamma radiations and neutron. For the design, the value of term source gamma is 25.77±0.20μSv.h -1 and the value of term source neutron is 7.88±0.35μSv.h -1 are used for the thickness of the walls. The importance of the design makes it possible to attenuate to the maximum doses and rates dose until the total absorption of the radiations. [fr

  2. Investigation of Size-Dependency in Free-Vibration of Micro-Resonators Based on the Strain Gradient Theory

    Directory of Open Access Journals (Sweden)

    R. Vatankhah

    Full Text Available Abstract This paper investigates the vibration behavior of micro-resonators based on the strain gradient theory, a non-classical continuum theory capable of capturing the size effect appearing in micro-scale structures. The micro-resonator is modeled as a clamped-clamped micro-beam with an attached mass subjected to an axial force. The governing equations of motion and both classical and non-classical sets of boundary conditions are developed based on the strain gradient theory. The normalized natural frequency of the micro-resonator is evaluated and the influences of various parameters are assessed. In addition, the current results are compared to those of the classical and modified couple stress continuum theories.

  3. Simultaneous distributed strain and temperature sensing based on combined Raman–Brillouin scattering using Fabry–Perot lasers

    International Nuclear Information System (INIS)

    Bolognini, Gabriele; Soto, Marcelo A; Di Pasquale, Fabrizio


    An investigation is performed of the possibility of achieving simultaneous distributed strain and temperature sensing based on hybrid Raman–Brillouin scattering with the use of multi-wavelength optical sources such as common Fabry–Perot (FP) lasers. By employing a self-heterodyne detection scheme based on a multi-wavelength optical local oscillator, the benefits of FP lasers are fully exploited, allowing for high-power Raman intensity measurements and a simultaneous high-accuracy detection of the Brillouin frequency shift parameter for each FP longitudinal mode. Experimental results point out a significant reduction of coherent Rayleigh noise, and highlight the enhanced performance in hybrid Raman–Brillouin sensing when using FP lasers; in particular using standard FP lasers at 1550 nm results in about 12 dB (7 dB) temperature (strain) accuracy improvement at 25 km sensing distance with respect to the use of standard distributed feedback lasers

  4. Simultaneous measurement of strain, temperature and refractive index based on multimode interference, fiber tapering and fiber Bragg gratings

    International Nuclear Information System (INIS)

    Oliveira, Ricardo; Osório, Jonas H; Aristilde, Stenio; Cordeiro, Cristiano M B; Bilro, Lúcia; Nogueira, Rogerio N


    We report the development of an optical fiber sensor capable of simultaneously measuring strain, temperature and refractive index. The sensor is based on the combination of two fiber Bragg gratings written in a standard single-mode fiber, one in an untapered region and another in a tapered region, spliced to a no-core fiber. The possibility of simultaneously measuring three parameters relies on the different sensitivity responses of each part of the sensor. The results have shown the possibility of measuring three parameters simultaneously with a resolution of 3.77 με , 1.36 °C and 5  ×  10 −4 , respectively for strain, temperature and refractive index. On top of the multiparameter ability, the simple production and combination of all the parts involved on this optical-fiber-based sensor is an attractive feature for several sensing applications. (paper)

  5. Microarray-based comparative genomic profiling of reference strains and selected Canadian field isolates of Actinobacillus pleuropneumoniae

    Directory of Open Access Journals (Sweden)

    MacInnes Janet I


    Full Text Available Abstract Background Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, is a highly contagious respiratory pathogen that causes severe losses to the swine industry worldwide. Current commercially-available vaccines are of limited value because they do not induce cross-serovar immunity and do not prevent development of the carrier state. Microarray-based comparative genomic hybridizations (M-CGH were used to estimate whole genomic diversity of representative Actinobacillus pleuropneumoniae strains. Our goal was to identify conserved genes, especially those predicted to encode outer membrane proteins and lipoproteins because of their potential for the development of more effective vaccines. Results Using hierarchical clustering, our M-CGH results showed that the majority of the genes in the genome of the serovar 5 A. pleuropneumoniae L20 strain were conserved in the reference strains of all 15 serovars and in representative field isolates. Fifty-eight conserved genes predicted to encode for outer membrane proteins or lipoproteins were identified. As well, there were several clusters of diverged or absent genes including those associated with capsule biosynthesis, toxin production as well as genes typically associated with mobile elements. Conclusion Although A. pleuropneumoniae strains are essentially clonal, M-CGH analysis of the reference strains of the fifteen serovars and representative field isolates revealed several classes of genes that were divergent or absent. Not surprisingly, these included genes associated with capsule biosynthesis as the capsule is associated with sero-specificity. Several of the conserved genes were identified as candidates for vaccine development, and we conclude that M-CGH is a valuable tool for reverse vaccinology.

  6. Quality and characteristics of fermented ginseng seed oil based on bacterial strain and extraction method

    Directory of Open Access Journals (Sweden)

    Myung-Hee Lee


    Results and Conclusion: The color of the fermented ginseng seed oil did not differ greatly according to the fermentation or extraction method. The highest phenolic compound content recovered with the use of supercritical fluid extraction combined with fermentation using the Bacillus subtilis Korea Food Research Institute (KFRI 1127 strain. The fatty acid composition did not differ greatly according to fermentation strain and extraction method. The phytosterol content of ginseng seed oil fermented with Bacillus subtilis KFRI 1127 and extracted using the supercritical fluid method was highest at 983.58 mg/100 g. Therefore, our results suggested that the ginseng seed oil fermented with Bacillus subtilis KFRI 1127 and extracted using the supercritical fluid method can yield a higher content of bioactive ingredients, such as phenolics, and phytosterols, without impacting the color or fatty acid composition of the product.

  7. Highly Sensitive and Stretchable Strain Sensor Based on Ag@CNTs. (United States)

    Zhang, Qiang; Liu, Lihua; Zhao, Dong; Duan, Qianqian; Ji, Jianlong; Jian, Aoqun; Zhang, Wendong; Sang, Shengbo


    Due to the rapid development and superb performance of electronic skin, we propose a highly sensitive and stretchable temperature and strain sensor. Silver nanoparticles coated carbon nanowires (Ag@CNT) nanomaterials with different Ag concentrations were synthesized. After the morphology and components of the nanomaterials were demonstrated, the sensors composed of Polydimethylsiloxane (PDMS) and CNTs or Ag@CNTs were prepared via a simple template method. Then, the electronic properties and piezoresistive effects of the sensors were tested. Characterization results present excellent performance of the sensors for the highest gauge factor (GF) of the linear region between 0-17.3% of the sensor with Ag@CNTs1 was 137.6, the sensor with Ag@CNTs2 under the strain in the range of 0-54.8% exhibiting a perfect linearity and the GF of the sensor with Ag@CNTs2 was 14.9.

  8. 2D modeling based comprehensive analysis of short channel effects in DMG strained VSTB FET (United States)

    Saha, Priyanka; Banerjee, Pritha; Sarkar, Subir Kumar


    The paper aims to develop two dimensional analytical model of the proposed dual material (DM) Vertical Super Thin Body (VSTB) strained Field Effect Transistor (FET) with focus on its short channel behaviour in nanometer regime. Electrostatic potential across gate/channel and dielectric wall/channel interface is derived by solving 2D Poisson's equation with parabolic approximation method by applying appropriate boundary conditions. Threshold voltage is then calculated by using the criteria of minimum surface potential considering both gate and dielectric wall side potential. Performance analysis of the present structure is demonstrated in terms of potential, electric field, threshold voltage characteristics and subthreshold behaviour by varying various device parameters and applied biases. Effect of application of strain in channel is further explored to establish the superiority of the proposed device in comparison to conventional VSTB FET counterpart. All analytical results are compared with Silvaco ATLAS device simulated data to substantiate the accuracy of our derived model.


    Czech Academy of Sciences Publication Activity Database

    Petrenec, Martin; Man, Jiří; Obrtlík, Karel; Polák, Jaroslav

    308/2005, č. 86 (2005), s. 269-274 ISSN 1429-6055. [Metody oceny struktury oraz wlasności materialów i wyrobów. Ustroń-Jaszowiec, 07.12.2005-09.12.2005] Institutional research plan: CEZ:AV0Z20410507 Keywords : low cycle fatigue * superalloy * cyclic strain localization Subject RIV: JL - Materials Fatigue, Friction Mechanics

  10. Strain sensors for civil engineering application based on CoFeCrSiB amorphous ribbons

    Czech Academy of Sciences Publication Activity Database

    Bydžovský, J.; Kollár, M.; Jančárik, V.; Švec, P.; Kraus, Luděk


    Roč. 52, Suppl. A (2002), s. A117-A120 ISSN 0011-4626. [Czech and Slovak Conference on Magnetism. Košice, 20.08.2001-23.08.2001] Grant - others:NATO(XX) SfP973649; VEGA(XX) 1/7609/20 Institutional research plan: CEZ:AV0Z1010914 Keywords : magnetic amorphous ribbon * stress-induced anisotropy * strain sensor Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.311, year: 2002

  11. An overview of the GAGE cancer/testis antigen family with the inclusion of newly identified members

    DEFF Research Database (Denmark)

    Gjerstorff, M F; Ditzel, H J


    . This review describes the structure and phylogeny of the GAGE family members and presents a revised nomenclature, which will enable a more clear distinction of genes and gene products. The GAGE gene locus at chromosome X p11.23 consists of at least 16 genes, each of which is located in one of an equal number...... of highly conserved tandem repeats, and more genes remain to be identified. These genes are likely the creation of unequal replication under positive selection after the divergence of primates from other mammals. The encoded products are predicted to be highly similar small acidic proteins involved in germ...

  12. Investigation on strain sensing properties of carbon-based nanocomposites for structural aircraft applications (United States)

    Lamberti, Patrizia; Spinelli, Giovanni; Tucci, Vincenzo; Guadagno, Liberata; Vertuccio, Luigi; Russo, Salvatore


    The mechanical and electrical properties of a thermosetting epoxy resin particularly indicated for the realization of structural aeronautic components and reinforced with multiwalled carbon nanotubes (MWCNTs, at 0.3 wt%) are investigated for specimens subjected to cycles and different levels of applied strain (i.e. ɛ) loaded both in axial tension and flexural mode. It is found that the piezoresistive behavior of the resulting nanocomposite evaluated in terms of variation of the electrical resistance is strongly affected by the applied mechanical stress mainly due to the high sensibility and consequent rearrangement of the electrical percolating network formed by MWCNTs in the composite at rest or even under a small strain. In fact, the variations in electrical resistance that occur during the mechanical stress are correlated to the deformation exhibited by the nanocomposites. In particular, the overall response of electrical resistance of the composite is characterized by a linear increase with the strain at least in the region of elastic deformation of the material in which the gauge factor (i.e. G.F.) of the sensor is usually evaluated. Therefore, the present study aims at investigating the possible use of the nanotechnology for application of embedded sensor systems in composite structures thus having capability of self-sensing and of responding to the surrounding environmental changes, which are some fundamental requirements especially for structural aircraft monitoring applications.

  13. Microstructure and strain rate effects on the mechanical behavior of particle reinforced epoxy-based reactive materials (United States)

    White, Bradley William

    The effects of reactive metal particles on the microstructure and mechanical properties of epoxy-based composites is investigated in this work. Particle reinforced polymer composites show promise as structural energetic materials that can provide structural strength while simultaneously being capable of releasing large amounts of chemical energy through highly exothermic reactions occurring between the particles and with the matrix. This advanced class of materials is advantageous due to the decreased amount of high density inert casings needed for typical energetic materials and for their ability to increase payload expectancy and decrease collateral damage. Structural energetic materials can be comprised of reactive particles that undergo thermite or intermetallic reactions. In this work nickel (Ni) and aluminum (Al) particles were chosen as reinforcing constituents due to their well characterized mechanical and energetic properties. Although, the reactivity of nickel and aluminum is well characterized, the effects of their particle size, volume fractions, and spatial distribution on the mechanical behavior of the epoxy matrix and composite, across a large range of strain rates, are not well understood. To examine these effects castings of epoxy reinforced with 20--40 vol.% Al and 0--10 vol.% Ni were prepared, while varying the aluminum nominal particle size from 5 to 50 mum and holding the nickel nominal particle size constant at 50 mum. Through these variations eight composite materials were produced, possessing unique microstructures exhibiting different particle spatial distributions and constituent makeup. In order to correlate the microstructure to the constitutive response of the composites, techniques such as nearest-neighbor distances, and multiscale analysis of area fractions (MSAAF) were used to quantitatively characterize the microstructures. The composites were investigated under quasi-static and dynamic compressive loading conditions to characterize

  14. Integrate genome-based assessment of safety for probiotic strains: Bacillus coagulans GBI-30, 6086 as a case study. (United States)

    Salvetti, Elisa; Orrù, Luigi; Capozzi, Vittorio; Martina, Alessia; Lamontanara, Antonella; Keller, David; Cash, Howard; Felis, Giovanna E; Cattivelli, Luigi; Torriani, Sandra; Spano, Giuseppe


    Probiotics are microorganisms that confer beneficial effects on the host; nevertheless, before being allowed for human consumption, their safety must be verified with accurate protocols. In the genomic era, such procedures should take into account the genomic-based approaches. This study aims at assessing the safety traits of Bacillus coagulans GBI-30, 6086 integrating the most updated genomics-based procedures and conventional phenotypic assays. Special attention was paid to putative virulence factors (VF), antibiotic resistance (AR) genes and genes encoding enzymes responsible for harmful metabolites (i.e. biogenic amines, BAs). This probiotic strain was phenotypically resistant to streptomycin and kanamycin, although the genome analysis suggested that the AR-related genes were not easily transferrable to other bacteria, and no other genes with potential safety risks, such as those related to VF or BA production, were retrieved. Furthermore, no unstable elements that could potentially lead to genomic rearrangements were detected. Moreover, a workflow is proposed to allow the proper taxonomic identification of a microbial strain and the accurate evaluation of risk-related gene traits, combining whole genome sequencing analysis with updated bioinformatics tools and standard phenotypic assays. The workflow presented can be generalized as a guideline for the safety investigation of novel probiotic strains to help stakeholders (from scientists to manufacturers and consumers) to meet regulatory requirements and avoid misleading information.

  15. Fatigue life evaluation based on welding residual stress relaxation and notch strain approach for cruciform welded joint

    International Nuclear Information System (INIS)

    Han, Jeong Woo; Han, Seung Ho; Shin, Byung Chun; Kim, Jae Hoon


    The fatigue strength of welded joint is influenced by the welding residual stress which is relaxed depending on local stress distributed in vicinity of stress raisers, eg. under cut, overlap and blow hole. To evaluate its fatigue life the geometry of the stress raisers and the welding residual stress should be taken into account. The several methods based on notch strain approach have been proposed in order to consider the two factors above mentioned. These methods, however, have shown considerable differences between analytical and experimental results. It is due to the fact that the amount of the relaxed welding residual stress evaluated by the cyclic stress-strain relationship do not correspond with that occurred in reality. In this paper the residual stress relaxation model based on experimental results was used in order to reduce the discrepancy of the estimated amount of the relaxed welding residual stress. Under an assumption of the superimposition of the relaxed welding residual stress and the local stress, a modified notch strain approach was proposed and verified to the cruciform welded joint

  16. Strain Localization and Weakening Processes in Viscously Deforming Rocks: Numerical Modeling Based on Laboratory Torsion Experiments (United States)

    Doehmann, M.; Brune, S.; Nardini, L.; Rybacki, E.; Dresen, G.


    Strain localization is an ubiquitous process in earth materials observed over a broad range of scales in space and time. Localized deformation and the formation of shear zones and faults typically involves material softening by various processes, like shear heating and grain size reduction. Numerical modeling enables us to study the complex physical and chemical weakening processes by separating the effect of individual parameters and boundary conditions. Using simple piece-wise linear functions for the parametrization of weakening processes allows studying a system at a chosen (lower) level of complexity (e.g. Cyprych et al., 2016). In this study, we utilize a finite element model to test two weakening laws that reduce the strength of the material depending on either the I) amount of accumulated strain or II) deformational work. Our 2D Cartesian models are benchmarked to single inclusion torsion experiments performed at elevated temperatures of 900 °C and pressures of up to 400 MPa (Rybacki et al., 2014). The experiments were performed on Carrara marble samples containing a weak Solnhofen limestone inclusion at a maximum strain rate of 2.0*10-4 s-1. Our models are designed to reproduce shear deformation of a hollow cylinder equivalent to the laboratory setup, such that material leaving one side of the model in shear direction enters again on the opposite side using periodic boundary conditions. Similar to the laboratory tests, we applied constant strain rate and constant stress boundary conditions.We use our model to investigate the time-dependent distribution of stress and strain and the effect of different parameters. For instance, inclusion rotation is shown to be strongly dependent on the viscosity ratio between matrix and inclusion and stronger ductile weakening increases the localization rate while decreasing shear zone width. The most suitable weakening law for representation of ductile rock is determined by combining the results of parameter tests with

  17. Peri-Implant Strain in an In Vitro Model. (United States)

    Hussaini, Souheil; Vaidyanathan, Tritala K; Wadkar, Abhinav P; Quran, Firas A Al; Ehrenberg, David; Weiner, Saul


    An in vitro experimental model was designed and tested to determine the influence that peri-implant strain may have on the overall crestal bone. Strain gages were attached to polymethylmethacrylate (PMMA) models containing a screw-type root form implant at sites 1 mm from the resin-implant interface. Three different types of crown superstructures (cemented, 1-screw [UCLA] and 2-screw abutment types) were tested. Loading (1 Hz, 200 N load) was performed using a MTS Mechanical Test System. The strain gage data were stored and organized in a computer for statistical treatment. Strains for all abutment types did not exceed the physiological range for modeling and remodeling of cancellous bone, 200-2500 με (microstrain). For approximately one-quarter of the trials, the strain values were less than 200 με the zone for bone atrophy. The mean microstrain obtained was 517.7 με. In conclusion, the peri-implant strain in this in vitro model did not exceed the physiologic range of bone remodeling under axial occlusal loading.

  18. Development of a New Gradient Based Strain-Criterion for Prediction of Bendability in Quality Assurance and FEA (United States)

    Denninger, Ralf; Liewald, Mathias; Sindel, Manfred


    Numerical simulation systems are more and more used in process development of car bodies. Nowadays, also the hemming process is optimised in FEA. Thus, the analysing of process robustness calls for a failure criterion for the specific bending and hemming load condition. For that purpose the experimental determination of bendability under various pre-load conditions that occur in real production, e.g. during deep drawing in press shop, is content of this contribution. Using these experimental results, a new approach for a strain-gradient based failure criterion for bending operations is presented to optimise bendability prediction. The bending-strain-gradient approach can be used both in production related departments of quality assurance as well as for simulative process design or process validation for vehicle manufacturing planning.

  19. Metabolomics-based prediction models of yeast strains for screening of metabolites contributing to ethanol stress tolerance (United States)

    Hashim, Z.; Fukusaki, E.


    The increased demand for clean, sustainable and renewable energy resources has driven the development of various microbial systems to produce biofuels. One of such systems is the ethanol-producing yeast. Although yeast produces ethanol naturally using its native pathways, production yield is low and requires improvement for commercial biofuel production. Moreover, ethanol is toxic to yeast and thus ethanol tolerance should be improved to further enhance ethanol production. In this study, we employed metabolomics-based strategy using 30 single-gene deleted yeast strains to construct multivariate models for ethanol tolerance and screen metabolites that relate to ethanol sensitivity/tolerance. The information obtained from this study can be used as an input for strain improvement via metabolic engineering.

  20. Refractive index and strain sensor based on twin-core fiber with a novel T-shaped taper (United States)

    Zhang, Chuanbiao; Ning, Tigang; Li, Jing; Zheng, JingJing; Gao, Xuekai; Pei, Li


    A compact in-fiber Mach-Zehnder interferometer (MZI) based on twin-core fiber (TCF) with a novel T-shaped taper is proposed and demonstrated. The taper was firstly fabricated by a short section of TCF, and then spliced with a section of cleaved single mode fiber (SMF). When the light transmit into the TCF, multiple modes will be excited and will propagate within the TCF. In experiment, the proposed device had a maximum interferometric extinction ratio about 17 dB. And the refractive index (RI), strain, and temperature response properties of the sensor have been investigated, which show a relatively high RI, strain sensitivity and low temperature cross sensitivity. Hence, the sensor can be a suitable candidate in the biochemical and physical sensing applications. And due to its easy and controllable fabrication, the novel drawing technology can be applied to more multicore optical fibers.

  1. EBSD-based techniques for characterization of microstructural restoration processes during annealing of metals deformed to large plastic strains

    DEFF Research Database (Denmark)

    Godfrey, A.; Mishin, Oleg; Yu, Tianbo


    Some methods for quantitative characterization of the microstructures deformed to large plastic strains both before and after annealing are discussed and illustrated using examples of samples after equal channel angular extrusion and cold-rolling. It is emphasized that the microstructures...... in such deformed samples exhibit a heterogeneity in the microstructural refinement by high angle boundaries. Based on this, a new parameter describing the fraction of regions containing predominantly low angle boundaries is introduced. This parameter has some advantages over the simpler high angle boundary...... on mode of the distribution of dislocation cell sizes is outlined, and it is demonstrated how this parameter can be used to investigate the uniformity, or otherwise, of the restoration processes occurring during annealing of metals deformed to large plastic strains. © (2012) Trans Tech Publications...

  2. Enhanced FBG sensor-based system performance assessment for monitoring strain along a prestressed CFRP rod in structural monitoring

    DEFF Research Database (Denmark)

    Kerrouche, A.; Boyle, W.J.O.; Sun, T.


    of the existing FBG-based system and the evaluation of the software developed to be compatible with a resolution reaching as high as +/- 0.15 mu epsilon is presented. The system has been tested under particular conditions where a prestressed CFRP (carbon fiber reinforced polymer) rod to which a FBG sensor......Fiber Bragg grating (FBG) sensor-based systems have been widely used for many engineering applications including most recently a number of applications in structural health monitoring. It is well known that strain and temperature both affect the FBG spectrum which in the interrogation system...

  3. Estimation of lattice strain for zirconia nanoparticles based on Williamson- Hall analysis

    Energy Technology Data Exchange (ETDEWEB)

    Aly, Kamal A., E-mail: [Physics Department, Faculty of Science & Arts, Khullais, University of Jeddah, Jeddah (Saudi Arabia); Physics Department, Faculty of Science, Al-Azhar University, Assiut Branch, Assiut (Egypt); Khalil, N.M. [Chemistry Department, Faculty of Science & Arts, Khullais, University of Jeddah, Jeddah (Saudi Arabia); Refractories, Ceramics and Building Materials Department, National Research Centre, 12311, Cairo (Egypt); Algamal, Yousif [Chemistry Department, Faculty of Science & Arts, Khullais, University of Jeddah, Jeddah (Saudi Arabia); Saleem, Qaid M.A. [Chemistry Department, Faculty of Science & Arts, Khullais, University of Jeddah, Jeddah (Saudi Arabia); Aden University, Shabwa (Yemen)


    Nanoparticles of Zirconia were prepared (ZrO{sub 2}) by the neutralization of zirconium oxychloride octahydrate (ZrOCl{sub 2}-8H{sub 2}O) (2M) and ammonia solution (2M) at pH 8. The ZrO{sub 2} crystalline state was revealed by X-ray diffraction (XRD). The analysis of Scanning electron microscopy (SEM) and Transmission Electron microscope (TEM) images reveals that the as-synthesized ZrO{sub 2} particles at firing temperature of 800 °C are uniform and of range of 30 nm. Increasing of the temperature up to 1100 °C leads to the increase in particle size and alters the powders shape due to agglomeration arose from zirconia calcination as well as the increase in particle size. The X-ray peak broadening analysis (XRDBA) was used in the estimation of the crystalline size. Williamson-Hall (W-H) analysis was applied successfully to determine the energy density, stress, and the strain values via uniform deformation model (UDM), uniform deformation stress model (UDSM) and uniform deformation energy density model (UDEDM). The mean of the strain root square was calculated. The different strain values obtained from these models predicting the zirconia isotropic behavior. In addition to that, the W-H analysis results were discussed in terms of that obtained by Scherrer’s relationship, SEM and TEM images. - Graphical abstract: XRD patterns for zirconia nano-particles at different calcined temperature. - Highlights: • Nanoparticles of Zirconia (ZrO{sub 2}) were synthesized. • The ZrO{sub 2} crystalline state was revealed by XRD, SEM and TEM. • SEM and TEM images reveals that the ZrO{sub 2} particles are uniform and relatively small. • Both blocky particles and the powders shape are affected by the firing temperature. • The crystalline sizes were estimated using X-ray peak broadening analysis (XRDBA).

  4. Spiking Phineas Gage: a neurocomputational theory of cognitive-affective integration in decision making. (United States)

    Wagar, Brandon M; Thagard, Paul


    The authors present a neurological theory of how cognitive information and emotional information are integrated in the nucleus accumbens during effective decision making. They describe how the nucleus accumbens acts as a gateway to integrate cognitive information from the ventromedial prefrontal cortex and the hippocampus with emotional information from the amygdala. The authors have modeled this integration by a network of spiking artificial neurons organized into separate areas and used this computational model to simulate 2 kinds of cognitive-affective integration. The model simulates successful performance by people with normal cognitive-affective integration. The model also simulates the historical case of Phineas Gage as well as subsequent patients whose ability to make decisions became impeded by damage to the ventromedial prefrontal cortex.

  5. Silica-Based and Borate-Based, Titania-Containing Bioactive Coatings Characterization: Critical Strain Energy Release Rate, Residual Stresses, Hardness, and Thermal Expansion

    Directory of Open Access Journals (Sweden)

    Omar Rodriguez


    Full Text Available Silica-based and borate-based glass series, with increasing amounts of TiO2 incorporated, are characterized in terms of their mechanical properties relevant to their use as metallic coating materials. It is observed that borate-based glasses exhibit CTE (Coefficient of Thermal Expansion closer to the substrate’s (Ti6Al4V CTE, translating into higher mode I critical strain energy release rates of glasses and compressive residual stresses and strains at the coating/substrate interface, outperforming the silica-based glasses counterparts. An increase in the content of TiO2 in the glasses results in an increase in the mode I critical strain energy release rate for both the bulk glass and for the coating/substrate system, proving that the addition of TiO2 to the glass structure enhances its toughness, while decreasing its bulk hardness. Borate-based glass BRT3, with 15 mol % TiO2 incorporated, exhibits superior properties overall compared to the other proposed glasses in this work, as well as 45S5 Bioglass® and Pyrex.

  6. Highly stretchable strain sensor based on polyurethane substrate using hydrogen bond-assisted laminated structure for monitoring of tiny human motions (United States)

    Huang, Ying; Zhao, Yunong; Wang, Yang; Guo, Xiaohui; Zhang, Yangyang; Liu, Ping; Liu, Caixia; Zhang, Yugang


    Strain sensors used as flexible and wearable electronic devices have improved prospects in the fields of artificial skin, robotics, human-machine interfaces, and healthcare. This work introduces a highly stretchable fiber-based strain sensor with a laminated structure made up of a graphene nanoplatelet layer and a carbon black/single-walled carbon nanotube synergetic conductive network layer. An ultrathin, flexible, and elastic two-layer polyurethane (PU) yarn substrate was successively deposited by a novel chemical bonding-based layered dip-coating process. These strain sensors demonstrated high stretchability (˜350%), little hysteresis, and long-term durability (over 2400 cycles) due to the favorable tensile properties of the PU substrate. The linearity of the strain sensor could reach an adjusted R-squared of 0.990 at 100% strain, which is better than most of the recently reported strain sensors. Meanwhile, the strain sensor exhibited good sensibility, rapid response, and a lower detection limit. The lower detection limit benefited from the hydrogen bond-assisted laminated structure and continuous conductive path. Finally, a series of experiments were carried out based on the special features of the PU strain sensor to show its capacity of detecting and monitoring tiny human motions.

  7. A flow cytometry-based assay for quantifying non-plaque forming strains of yellow fever virus.

    Directory of Open Access Journals (Sweden)

    Erika Hammarlund

    Full Text Available Primary clinical isolates of yellow fever virus can be difficult to quantitate by standard in vitro methods because they may not form discernable plaques or induce a measurable cytopathic effect (CPE on cell monolayers. In our hands, the Dakar strain of yellow fever virus (YFV-Dakar could not be measured by plaque assay (PA, focus-forming assay (FFA, or by measurement of CPE. For these reasons, we developed a YFV-specific monoclonal antibody (3A8.B6 and used it to optimize a highly sensitive flow cytometry-based tissue culture limiting dilution assay (TC-LDA to measure levels of infectious virus. The TC-LDA was performed by incubating serial dilutions of virus in replicate wells of C6/36 cells and stained intracellularly for virus with MAb 3A8.B6. Using this approach, we could reproducibly quantitate YFV-Dakar in tissue culture supernatants as well as from the serum of viremic rhesus macaques experimentally infected with YFV-Dakar. Moreover, the TC-LDA approach was >10-fold more sensitive than standard plaque assay for quantitating typical plaque-forming strains of YFV including YFV-17D and YFV-FNV (French neurotropic vaccine. Together, these results indicate that the TC-LDA technique is effective for quantitating both plaque-forming and non-plaque-forming strains of yellow fever virus, and this methodology may be readily adapted for the study and quantitation of other non-plaque-forming viruses.

  8. Omni-Purpose Stretchable Strain Sensor Based on a Highly Dense Nanocracking Structure for Whole-Body Motion Monitoring. (United States)

    Jeon, Hyungkook; Hong, Seong Kyung; Kim, Min Seo; Cho, Seong J; Lim, Geunbae


    Here, we report an omni-purpose stretchable strain sensor (OPSS sensor) based on a nanocracking structure for monitoring whole-body motions including both joint-level and skin-level motions. By controlling and optimizing the nanocracking structure, inspired by the spider sensory system, the OPSS sensor is endowed with both high sensitivity (gauge factor ≈ 30) and a wide working range (strain up to 150%) under great linearity (R 2 = 0.9814) and fast response time (sensor has advantages of being extremely simple, patternable, integrated circuit-compatible, and reliable in terms of reproducibility. Using the OPSS sensor, we detected various human body motions including both moving of joints and subtle deforming of skin such as pulsation. As specific medical applications of the sensor, we also successfully developed a glove-type hand motion detector and a real-time Morse code communication system for patients with general paralysis. Therefore, considering the outstanding sensing performances, great advantages of the fabrication process, and successful results from a variety of practical applications, we believe that the OPSS sensor is a highly suitable strain sensor for whole-body motion monitoring and has potential for a wide range of applications, such as medical robotics and wearable healthcare devices.

  9. Subband Structure and Effective Mass in the Inversion Layer of a Strain Si-Based Alloy P-Type MOSFET. (United States)

    Chen, Kuan-Ting; Fan, Jun Wei; Chang, Shu-Tong; Lin, Chung-Yi


    In this paper, the subband structure and effective mass of an Si-based alloy inversion layer in a PMOSFET are studied theoretically. The strain condition considered in our calculations is the intrinsic strain resulting from growth of the silicon-carbon alloy on a (001) Si substrate and mechanical uniaxial stress. The quantum confinement effect resulting from the vertically effective electric field was incorporated into the k · p calculation. The distinct effective mass, such as the quantization effective mass and the density-of-states (DOS) effective mass, as well as the subband structure of the silicon-carbon alloy inversion layer for a PMOSFET under substrate strain and various effective electric field strengths, were all investigated. Ore results show that subband structure of relaxed silicon-carbon alloys with low carbon content are almost the same as silicon. We find that an external stress applied parallel to the channel direction can efficiently reduce the effective mass along the channel direction, thus producing hole mobility enhancement.

  10. Simultaneous strain and temperature sensor based on polarization maintaining fiber and multimode fiber (United States)

    Xing, Rui; Dong, Changbin; Wang, Zixiao; Wu, Yue; Yang, Yuguang; Jian, Shuisheng


    A novel, simultaneous strain and temperature sensor utilizing polarization maintaining fiber (PMF) and multimode fiber (MMF) is proposed and experimentally demonstrated in this paper. The sensing head of this sensor can be obtained by splicing PMF and MMF in the structure of PMF-MMF-PMF. The extinction ratio of the transmission spectrum can be over 30 dB. The strain sensitivities of sensor by two spectrum dips can be 1.01 pm/με and 1.27 pm/με in the range from 0 to 2000 με. Meanwhile, the temperature sensitivities of 49 pm/°C and 41 pm/°C can be achieved by two spectrum dips in the range from 30 °C to 70 °C. The sensitivity difference between the two spectrum dips can be used to realize dual parameters fiber sensing. This sensor exhibits the advantages of simple fabrication, compact structure and multi-purpose measuring. It may have the great potential in fields of robot arms and artificial limbs.

  11. Research of a smart cutting tool based on MEMS strain gauge (United States)

    Zhao, Y.; Zhao, Y. L.; Shao, YW; Hu, T. J.; Zhang, Q.; Ge, X. H.


    Cutting force is an important factor that affects machining accuracy, cutting vibration and tool wear. Machining condition monitoring by cutting force measurement is a key technology for intelligent manufacture. Current cutting force sensors exist problems of large volume, complex structure and poor compatibility in practical application, for these problems, a smart cutting tool is proposed in this paper for cutting force measurement. Commercial MEMS (Micro-Electro-Mechanical System) strain gauges with high sensitivity and small size are adopted as transducing element of the smart tool, and a structure optimized cutting tool is fabricated for MEMS strain gauge bonding. Static calibration results show that the developed smart cutting tool is able to measure cutting forces in both X and Y directions, and the cross-interference error is within 3%. Its general accuracy is 3.35% and 3.27% in X and Y directions, and sensitivity is 0.1 mV/N, which is very suitable for measuring small cutting forces in high speed and precision machining. The smart cutting tool is portable and reliable for practical application in CNC machine tool.

  12. Modulation of persistent magnetoresistance by piezo-strain effect in manganite-based heterostructures (United States)

    Li, W.; Yan, H.; Chai, X. J.; Wang, S. H.; Dong, X. L.; Ren, L. X.; Chen, C. L.; Jin, K. X.


    Persistent magnetoresistance effects in the phase-separated Pr0.65(Ca0.25Sr0.75)0.35MnO3/SrTiO3 and Pr0.65(Ca0.25Sr0.75)0.35MnO3/0.7PbMg1/3Nb2/3O3-0.3PbTiO3 heterostructures under a low magnetic field are investigated. It is observed that the persistent magnetoresistance effects decrease with increasing temperatures and the values for the heterostructures on 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 and SrTiO3 substrates are about 86.6% and 33.2% at 40 K, respectively. More interestingly, the applied electric field on the 0.7PbMg1/3Nb2/3O3-0.3PbTiO3 substrate can suppress the persistent magnetoresistance effect, indicating that different energy landscapes can be dramatically modulated by the piezo-strain. These results are discussed in terms of the strain-induced competition in the ferromagnetic state and the charge-ordering phase by the energy scenario, which provide a promising approach for designing devices of electric-magnetic memories in all-oxide heterostructures.

  13. Metabolic regulation analysis of an ethanologenic Escherichia coli strain based on RT-PCR and enzymatic activities

    Directory of Open Access Journals (Sweden)

    Martinez Alfredo


    Full Text Available Abstract Background A metabolic regulation study was performed, based upon measurements of enzymatic activities, fermentation performance, and RT-PCR analysis of pathways related to central carbon metabolism, in an ethanologenic Escherichia coli strain (CCE14 derived from lineage C. In comparison with previous engineered strains, this E coli derivative has a higher ethanol production rate in mineral medium, as a result of the elevated heterologous expression of the chromosomally integrated genes encoding PDCZm and ADHZm (pyruvate decarboxylase and alcohol dehydrogenase from Zymomonas mobilis. It is suggested that this behavior might be due to lineage differences between E. coli W and C. Results This study demonstrated that the glycolytic flux is controlled, in this case, by reactions outside glycolysis, i.e., the fermentative pathways. Changes in ethanol production rate in this ethanologenic strain result in low organic acid production rates, and high glycolytic and ethanologenic fluxes, that correlate with enhanced transcription and enzymatic activity levels of PDCZm and ADHZm. Furthermore, a higher ethanol yield (90% of the theoretical in glucose-mineral media was obtained with CCE14 in comparison with previous engineered E. coli strains, such as KO11, that produces a 70% yield under the same conditions. Conclusion Results suggest that a higher ethanol formation rate, caused by ahigher PDCZm and ADHZm activities induces a metabolic state that cells compensate through enhanced glucose transport, ATP synthesis, and NAD-NADH+H turnover rates. These results show that glycolytic enzymatic activities, present in E. coli W and C under fermentative conditions, are sufficient to contend with increases in glucose consumption and product formation rates.

  14. Diagnostic tools based on minor groove binder probe technology for rapid identification of vaccinal and field strains of canine parvovirus type 2b. (United States)

    Decaro, Nicola; Martella, Vito; Elia, Gabriella; Desario, Costantina; Campolo, Marco; Buonavoglia, Domenico; Bellacicco, Anna Lucia; Tempesta, Maria; Buonavoglia, Canio


    TaqMan-based diagnostic tests have been developed for the identification of canine parvovirus type 2 (CPV-2) strains in the faeces of dogs with diarrhoea, including a minor groove binder (MGB) probe assay for identification of type 2-based vaccines and field strains (types 2a, 2b and 2c). Since type 2b vaccines have been licensed recently in Europe, two novel MGB assays were developed for discrimination between type 2b vaccines and field strains of CPV. Such assays have been found to be highly sensitive, specific and reproducible, allowing for simultaneous detection of type 2b vaccinal and field strains present in the same specimens. These new assays will help resolution of the diagnostic problems related to the detection of a type 2b strain in the faeces of dogs shortly after the administration of a type 2b vaccine.

  15. Static and Dynamic Strain Monitoring of Reinforced Concrete Components through Embedded Carbon Nanotube Cement-Based Sensors

    Directory of Open Access Journals (Sweden)

    Antonella D’Alessandro


    Full Text Available The paper presents a study on the use of cement-based sensors doped with carbon nanotubes as embedded smart sensors for static and dynamic strain monitoring of reinforced concrete (RC elements. Such novel sensors can be used for the monitoring of civil infrastructures. Because they are fabricated from a structural material and are easy to utilize, these sensors can be integrated into structural elements for monitoring of different types of constructions during their service life. Despite the scientific attention that such sensors have received in recent years, further research is needed to understand (i the repeatability and accuracy of sensors’ behavior over a meaningful number of sensors, (ii testing configurations and calibration methods, and (iii the sensors’ ability to provide static and dynamic strain measurements when actually embedded in RC elements. To address these research needs, this paper presents a preliminary characterization of the self-sensing capabilities and the dynamic properties of a meaningful number of cement-based sensors and studies their application as embedded sensors in a full-scale RC beam. Results from electrical and electromechanical tests conducted on small and full-scale specimens using different electrical measurement methods confirm that smart cement-based sensors show promise for both static and vibration-based structural health monitoring applications of concrete elements but that calibration of each sensor seems to be necessary.

  16. Bioactivity, Chemical Profiling, and 16S rRNA-Based Phylogeny of Pseudoalteromonas Strains Collected on a Global Research Cruise

    DEFF Research Database (Denmark)

    Vynne, Nikolaj Grønnegaard; Månsson, Maria; Nielsen, Kristian Fog


    One hundred one antibacterial Pseudoalteromonas strains that inhibited growth of a Vibrio anguillarum test strain were collected on a global research cruise (Galathea 3), and 51 of the strains repeatedly demonstrated antibacterial activity. Here, we profile secondary metabolites of these strains...

  17. MAGE-A1, GAGE and NY-ESO-1 cancer/testis antigen expression during human gonadal development

    DEFF Research Database (Denmark)

    Gjerstorff, Morten F; Kock, Kirsten; Nielsen, Ole


    BACKGROUND: Cancer/testis antigens (CTAs) are expressed in several cancers and during normal adult male germ cell differentiation. Little is known about their role in fetal development of human germ cells. METHODS: We examined expression of the CTAs MAGE-A1, GAGE and NY-ESO-1 in fetal gonads...

  18. Standard practice for strain controlled thermomechanical fatigue testing

    CERN Document Server

    American Society for Testing and Materials. Philadelphia


    1.1 This practice covers the determination of thermomechanical fatigue (TMF) properties of materials under uniaxially loaded strain-controlled conditions. A “thermomechanical” fatigue cycle is here defined as a condition where uniform temperature and strain fields over the specimen gage section are simultaneously varied and independently controlled. This practice is intended to address TMF testing performed in support of such activities as materials research and development, mechanical design, process and quality control, product performance, and failure analysis. While this practice is specific to strain-controlled testing, many sections will provide useful information for force-controlled or stress-controlled TMF testing. 1.2 This practice allows for any maximum and minimum values of temperature and mechanical strain, and temperature-mechanical strain phasing, with the restriction being that such parameters remain cyclically constant throughout the duration of the test. No restrictions are placed on en...

  19. Study of Post-Peak Strain Softening Mechanical Behaviour of Rock Material Based on Hoek–Brown Criterion


    Qibin Lin; Ping Cao; Peixin Wang


    In order to build the post-peak strain softening model of rock, the evolution laws of rock parameters m,s were obtained by using the evolutionary mode of piecewise linear function regarding the maximum principle stress. Based on the nonlinear Hoek–Brown criterion, the analytical relationship of the rock strength parameters m,s, cohesion c, and friction angle φ has been developed by theoretical derivation. According to the analysis on the four different types of rock, it is found that, within ...

  20. Clinical development of a novel inactivated poliomyelitis vaccine based on attenuated Sabin poliovirus strains. (United States)

    Verdijk, Pauline; Rots, Nynke Y; Bakker, Wilfried A M


    Following achievement of polio eradication, the routine use of all live-attenuated oral poliovirus vaccines should be discontinued. However, the costs per vaccine dose for the alternative inactivated poliovirus vaccine (IPV) are significantly higher and the current production capacity is not sufficient for worldwide distribution of the vaccine. In order to achieve cost-prize reduction and improve affordability, IPV production processes and dose-sparing strategies should be developed to facilitate local manufacture at a relatively lower cost. The use of attenuated Sabin instead of wild-type polio strains will provide additional safety during vaccine production and permits production in low-cost settings. Sabin-IPV is under development by several manufacturers. This article gives an overview of results from clinical trials with Sabin-IPV and discusses the requirements and challenges in the clinical development of this novel IPV.

  1. Antigen sparing with adjuvanted inactivated polio vaccine based on Sabin strains. (United States)

    Westdijk, Janny; Koedam, Patrick; Barro, Mario; Steil, Benjamin P; Collin, Nicolas; Vedvick, Thomas S; Bakker, Wilfried A M; van der Ley, Peter; Kersten, Gideon


    Six different adjuvants, each in combination with inactivated polio vaccine (IPV) produced with attenuated Sabin strains (sIPV), were evaluated for their ability to enhance virus neutralizing antibody titres (VNTs) in the rat potency model. The increase of VNTs was on average 3-, 15-, 24-fold with adjuvants after one immunization (serotypes 1, 2, and 3, respectively). Also after a boost immunization the VNTs of adjuvanted sIPV were on average another 7-20-27 times higher than after two inoculations of sIPV without adjuvant. The results indicate that it is feasible to increase the potency of inactivated polio vaccines by using adjuvants. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Nonlocal strain gradient theory calibration using molecular dynamics simulation based on small scale vibration of nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Mehralian, Fahimeh [Mechanical Engineering Department, Shahrekord University, Shahrekord (Iran, Islamic Republic of); Tadi Beni, Yaghoub, E-mail: [Faculty of Engineering, Shahrekord University, Shahrekord (Iran, Islamic Republic of); Karimi Zeverdejani, Mehran [Mechanical Engineering Department, Shahrekord University, Shahrekord (Iran, Islamic Republic of)


    Featured by two small length scale parameters, nonlocal strain gradient theory is utilized to investigate the free vibration of nanotubes. A new size-dependent shell model formulation is developed by using the first order shear deformation theory. The governing equations and boundary conditions are obtained using Hamilton's principle and solved for simply supported boundary condition. As main purpose of this study, since the values of two small length scale parameters are still unknown, they are calibrated by the means of molecular dynamics simulations (MDs). Then, the influences of different parameters such as nonlocal parameter, scale factor, length and thickness on vibration characteristics of nanotubes are studied. It is also shown that increase in thickness and decrease in length parameters intensify the effect of nonlocal parameter and scale factor.

  3. Maximum Likelihood based comparison of the specific growth rates for P. aeruginosa and four mutator strains

    DEFF Research Database (Denmark)

    Philipsen, Kirsten Riber; Christiansen, Lasse Engbo; Mandsberg, Lotte Frigaard


    with an exponentially decaying function of the time between observations is suggested. A model with a full covariance structure containing OD-dependent variance and an autocorrelation structure is compared to a model with variance only and with no variance or correlation implemented. It is shown that the model...... are used for parameter estimation. The data is log-transformed such that a linear model can be applied. The transformation changes the variance structure, and hence an OD-dependent variance is implemented in the model. The autocorrelation in the data is demonstrated, and a correlation model...... that best describes data is a model taking into account the full covariance structure. An inference study is made in order to determine whether the growth rate of the five bacteria strains is the same. After applying a likelihood-ratio test to models with a full covariance structure, it is concluded...

  4. Electro optical system to measure strains at high temperature (United States)

    Sciammarella, Cesar A.


    The measurement of strains at temperatures of the order of 1000 C has become a very important field of research. Technological advances in areas such as the analysis of high speed aircraft structures and high efficiency thermal engines require operational temperatures of this order of magnitude. Current techniques for the measurement of strains, such as electrical strain gages, are at the limit of their useful range and new methods need to be developed. Optical techniques are very attractive in this type of application because of their noncontacting nature. Holography is of particular interest because a minimal preparation of the surfaces is required. Optoelectronics holography is specially suited for this type of application, from the point of view of industrial use. There are a number of technical problems that need to be overcome to measure strains using holographic interferometry at high temperatures. Some of these problems are discussed, and solutions are given. A specimen instrumented with high temperature strains gages is used to compare the results of both technologies.

  5. Variation of Shrinkage Strain within the Depth of Concrete Beams

    Directory of Open Access Journals (Sweden)

    Jong-Hyun Jeong


    Full Text Available The variation of shrinkage strain within beam depth was examined through four series of time-dependent laboratory experiments on unreinforced concrete beam specimens. Two types of beam specimens, horizontally cast and vertically cast, were tested; shrinkage variation was observed in the horizontally cast specimens. This indicated that the shrinkage variation within the beam depth was due to water bleeding and tamping during the placement of the fresh concrete. Shrinkage strains were measured within the beam depth by two types of strain gages, surface-attached and embedded. The shrinkage strain distribution within the beam depth showed a consistent tendency for the two types of gages. The test beams were cut into four sections after completion of the test, and the cutting planes were divided into four equal sub-areas to measure the aggregate concentration for each sub-area of the cutting plane. The aggregate concentration increased towards the bottom of the beam. The shrinkage strain distribution was estimated by Hobbs’ equation, which accounts for the change of aggregate volume concentration.

  6. Investigation of a Cross-Correlation Based Optical Strain Measurement Technique for Detecting radial Growth on a Rotating Disk (United States)

    Clem, Michelle M.; Woike, Mark R.


    The Aeronautical Sciences Project under NASA`s Fundamental Aeronautics Program is extremely interested in the development of novel measurement technologies, such as optical surface measurements in the internal parts of a flow path, for in situ health monitoring of gas turbine engines. In situ health monitoring has the potential to detect flaws, i.e. cracks in key components, such as engine turbine disks, before the flaws lead to catastrophic failure. In the present study, a cross-correlation imaging technique is investigated in a proof-of-concept study as a possible optical technique to measure the radial growth and strain field on an already cracked sub-scale turbine engine disk under loaded conditions in the NASA Glenn Research Center`s High Precision Rotordynamics Laboratory. The optical strain measurement technique under investigation offers potential fault detection using an applied high-contrast random speckle pattern and imaging the pattern under unloaded and loaded conditions with a CCD camera. Spinning the cracked disk at high speeds induces an external load, resulting in a radial growth of the disk of approximately 50.0-im in the flawed region and hence, a localized strain field. When imaging the cracked disk under static conditions, the disk will be undistorted; however, during rotation the cracked region will grow radially, thus causing the applied particle pattern to be .shifted`. The resulting particle displacements between the two images will then be measured using the two-dimensional cross-correlation algorithms implemented in standard Particle Image Velocimetry (PIV) software to track the disk growth, which facilitates calculation of the localized strain field. In order to develop and validate this optical strain measurement technique an initial proof-of-concept experiment is carried out in a controlled environment. Using PIV optimization principles and guidelines, three potential speckle patterns, for future use on the rotating disk, are developed

  7. Efficacy, Safety, and Interactions of a Live Infectious Bursal Disease Virus Vaccine for Chickens Based on Strain IBD V877. (United States)

    Geerligs, Harm J; Ons, Ellen; Boelm, Gert Jan; Vancraeynest, Dieter


    Infectious bursal disease (IBD) is a highly contagious disease in young chickens which can result in high morbidity and mortality and also in great economic losses. The main target for the virus is the lymphoid tissue with a special predilection for the bursa of Fabricius. Several vaccines are available to control the disease. Intermediate plus vaccines are used in chickens with high maternal antibody titers which face high infection pressure. An example of an intermediate plus vaccine is a live vaccine based on IBD strain V877. The results of an efficacy study in commercial broilers with different levels of maternally derived antibodies (MDA) showed that the V877-based IBD vaccine can break through maternal antibody titers of higher than 1100 as determined by an IBD ELISA. The safety of the vaccine was demonstrated in a study in which specific-pathogen-free (SPF) chickens were vaccinated with a tenfold dose of the vaccine strain and a tenfold dose of the vaccine strain after five back passages in SPF chickens. The vaccine virus caused lesions, as could be expected for an intermediate plus vaccine, but the scores were not much higher than the maximal scores allowed for mild IBD vaccines in the European Pharmacopoeia, and reversion to virulence was absent. In studies in SPF chickens, there were no negative impacts by the IBD V877 vaccine on the efficacy of a live QX-like IB vaccine and a live Newcastle disease La Sota vaccine in vaccination challenge studies, although the IBD vaccine had a negative effect on the antibody response generated by the QX-like IB vaccine. It is concluded that the IBD V877 vaccine has the capacity to break through high levels of MDA, has a satisfactory safety profile, and interactions with other live vaccines are limited. In order to limit bursal lesions after vaccination it is recommended to confirm the presence of MDA before vaccinating with the V877 vaccine.

  8. Genotyping of Bacillus anthracis strains based on automated capillary 25-loci Multiple Locus Variable-Number Tandem Repeats Analysis

    Directory of Open Access Journals (Sweden)

    Ciervo Alessandra


    Full Text Available Abstract Background The genome of Bacillus anthracis, the etiological agent of anthrax, is highly monomorphic which makes differentiation between strains difficult. A Multiple Locus Variable-number tandem repeats (VNTR Analysis (MLVA assay based on 20 markers was previously described. It has considerable discrimination power, reproducibility, and low cost, especially since the markers proposed can be typed by agarose-gel electrophoresis. However in an emergency situation, faster genotyping and access to representative databases is necessary. Results Genotyping of B. anthracis reference strains and isolates from France and Italy was done using a 25 loci MLVA assay combining 21 previously described loci and 4 new ones. DNA was amplified in 4 multiplex PCR reactions and the length of the resulting 25 amplicons was estimated by automated capillary electrophoresis. The results were reproducible and the data were consistent with other gel based methods once differences in mobility patterns were taken into account. Some alleles previously unresolved by agarose gel electrophoresis could be resolved by capillary electrophoresis, thus further increasing the assay resolution. One particular locus, Bams30, is the result of a recombination between a 27 bp tandem repeat and a 9 bp tandem repeat. The analysis of the array illustrates the evolution process of tandem repeats. Conclusion In a crisis situation of suspected bioterrorism, standardization, speed and accuracy, together with the availability of reference typing data are important issues, as illustrated by the 2001 anthrax letters event. In this report we describe an upgrade of the previously published MLVA method for genotyping of B. anthracis and apply the method to the typing of French and Italian B. anthracis strain collections. The increased number of markers studied compared to reports using only 8 loci greatly improves the discrimination power of the technique. An Italian strain belonging to the

  9. Nonlocal strain gradient based wave dispersion behavior of smart rotating magneto-electro-elastic nanoplates (United States)

    Ebrahimi, Farzad; Dabbagh, Ali


    Main object of the present research is an exact investigation of wave propagation responses of smart rotating magneto-electro-elastic (MEE) graded nanoscale plates. In addition, effective material properties of functionally graded (FG) nanoplate are presumed to be calculated using the power-law formulations. Also, it has been tried to cover both softening and stiffness-hardening behaviors of nanostructures by the means of employing nonlocal strain gradient theory (NSGT). Due to increasing the accuracy of the presented model in predicting shear deformation effects, a refined higher-order plate theory is introduced. In order to cover the most enormous circumstances, maximum amount of load generated by plate’s rotation is considered. Furthermore, utilizing a developed form of Hamilton’s principle, containing magneto-electric effects, the nonlocal governing equations of MEE-FG rotating nanoplates are derived. An analytical solution is obtained to solve the governing equations and validity of the solution method is proven by comparing results from present method with those of former attempts. At last, outcomes are plotted in the framework of some figures to show the influences of various parameters such as wave number, nonlocality, length scale parameter, magnetic potential, electric voltage, gradient index and angular velocity on wave frequency, phase velocity and escape frequency of the examined nanoplate.

  10. Low-voltage, large-strain soft electrothermal actuators based on laser-reduced graphene oxide/Ag particle composites (United States)

    Wang, Qian; Li, Yu-Tao; Zhang, Tian-Yu; Wang, Dan-Yang; Tian, Ye; Yan, Jun-Chao; Tian, He; Yang, Yi; Yang, Fan; Ren, Tian-Ling


    In this paper, low-voltage, large-strain flexible electrothermal actuators (ETAs) based on laser-reduced graphene oxide (LRGO)/Ag particle composites were fabricated in a simple and cost-efficient process. By adding Ag particles to the LRGO, the sheet resistance decreased effectively. Under a driving voltage of 28 V, the actuator obtained a bending angle of 192° within 6 s. Besides, the bending deformation could be precisely controlled by the driving voltage ranging from 10° to 192°. Finally, a gripper composed of two actuators was demonstrated to manipulate a piece of polydimethylsiloxane block. With the advantages of low-voltage, fast-response, and easy-to-manufacture, the graphene based ETAs have a promising application in soft robotics and soft machines.

  11. Highly strained InAlP/InGaAs-based coupled double quantum wells on InP substrates (United States)

    Gozu, Shin-ichiro; Mozume, Teruo


    InAlP/InGaAs based coupled double quantum wells (CDQWs) are proposed for optelectronic devices utilizing intersubband transitions. The aim of the proposed CDQW structure was to reduce the Al volume as compared with that in InGaAs/AlAsSb(AlAs/InAlAs) based CDQWs. By careful consideration of the band gap energy as well as conduction band offset and lattice constants for III–V materials, highly strained InAlP was chosen as the barrier material. With the appropriate CDQW structure and under the optimized growth conditions, proposed CDQWs exhibited clear X-ray diffraction satellite peaks, and almost identical optical absorption spectrum as compared with the InGaAs/AlAs/InAlAs CDQWs.

  12. Evidence based selection of probiotic strains to promote astronaut health or alleviate symptoms of illness on long duration spaceflight missions. (United States)

    Douglas, G L; Voorhies, A A


    Spaceflight impacts multiple aspects of human physiology, which will require non-invasive countermeasures as mission length and distance from Earth increases and the capability for external medical intervention decreases. Studies on Earth have shown that probiotics have the potential to improve some of the conditions that have manifested during spaceflight, such as gastrointestinal distress, dermatitis, and respiratory infections. The constraints and risks of spaceflight make it imperative that probiotics are carefully selected based on their strain-specific benefits, doses, delivery mechanisms, and relevance to likely crew conditions prior to evaluation in astronauts. This review focuses on probiotics that have been incorporated into healthy human gastrointestinal microbiomes and associated clinically with improvements in inflammatory state or alleviation of symptoms of crew-relevant illness. These studies provide an evidence base for probiotic selection with the greatest potential to support crew health and well-being in spaceflight.

  13. DNA microarray-based genome comparison of a pathogenic and a nonpathogenic strain of Xylella fastidiosa delineates genes important for bacterial virulence. (United States)

    Koide, Tie; Zaini, Paulo A; Moreira, Leandro M; Vêncio, Ricardo Z N; Matsukuma, Adriana Y; Durham, Alan M; Teixeira, Diva C; El-Dorry, Hamza; Monteiro, Patrícia B; da Silva, Ana Claudia R; Verjovski-Almeida, Sergio; da Silva, Aline M; Gomes, Suely L


    Xylella fastidiosa is a phytopathogenic bacterium that causes serious diseases in a wide range of economically important crops. Despite extensive comparative analyses of genome sequences of Xylella pathogenic strains from different plant hosts, nonpathogenic strains have not been studied. In this report, we show that X. fastidiosa strain J1a12, associated with citrus variegated chlorosis (CVC), is nonpathogenic when injected into citrus and tobacco plants. Furthermore, a DNA microarray-based comparison of J1a12 with 9a5c, a CVC strain that is highly pathogenic and had its genome completely sequenced, revealed that 14 coding sequences of strain 9a5c are absent or highly divergent in strain J1a12. Among them, we found an arginase and a fimbrial adhesin precursor of type III pilus, which were confirmed to be absent in the nonpathogenic strain by PCR and DNA sequencing. The absence of arginase can be correlated to the inability of J1a12 to multiply in host plants. This enzyme has been recently shown to act as a bacterial survival mechanism by down-regulating host nitric oxide production. The lack of the adhesin precursor gene is in accordance with the less aggregated phenotype observed for J1a12 cells growing in vitro. Thus, the absence of both genes can be associated with the failure of the J1a12 strain to establish and spread in citrus and tobacco plants. These results provide the first detailed comparison between a nonpathogenic strain and a pathogenic strain of X. fastidiosa, constituting an important step towards understanding the molecular basis of the disease.

  14. Key volatile aroma compounds of lactic acid fermented malt based beverages - impact of lactic acid bacteria strains. (United States)

    Nsogning Dongmo, Sorelle; Sacher, Bertram; Kollmannsberger, Hubert; Becker, Thomas


    This study aims to define the aroma composition and key aroma compounds of barley malt wort beverages produced from fermentation using six lactic acid bacteria (LAB) strains. Gas chromatography mass spectrometry-olfactometry and flame ionization detection was employed; key aroma compounds were determined by means of aroma extract dilution analysis. Fifty-six detected volatile compounds were similar among beverages. However, significant differences were observed in the concentration of individual compounds. Key aroma compounds (flavor dilution (FD) factors ≥16) were β-damascenone, furaneol, phenylacetic acid, 2-phenylethanol, 4-vinylguaiacol, sotolon, methional, vanillin, acetic acid, nor-furaneol, guaiacol and ethyl 2-methylbutanoate. Furthermore, acetaldehyde had the greatest odor activity value of up to 4266. Sensory analyses revealed large differences in the flavor profile. Beverage from L. plantarum Lp. 758 showed the highest FD factors in key aroma compounds and was correlated to fruity flavors. Therefore, we suggest that suitable LAB strain selection may improve the flavor of malt based beverages. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Effect of zinc additions on oxide rupture strain and repassivation kinetics of iron-based alloys in 288 C water

    International Nuclear Information System (INIS)

    Angeliu, T.M.; Andresen, P.L.


    The effect of Zn water chemistry additions on the mechanism of intergranular stress corrosion cracking (IGSCC) of Fe-based alloys in water at 288 C was evaluated in terms of the slip-dissolution model. In this model, an increase in the oxide film rupture strain or surface film repassivation kinetics improved resistance to IGSCC. The oxide rupture strain of type 304L (UNS S30403) stainless steel (SS) increased up to a factor of two in deaerated and 200 ppb oxygenated, high-purity water ( 300 h of exposure. Repassivation kinetics experiments showed Zn additions of ∼ 100 ppb increased the repassivation rate of an Fe-12% Cr alloys up to a factor of two in various deaerated water environments at 288 C. Life prediction modeling revealed that the combination of a more ductile oxide film and faster repassivation kinetics resulted in a reduction in the overall crack growth rate (CGR) by at least a factor of four. This factor of improvement was consistent with data from compact tension experiments in similar environments where CGR decreased as the Zn addition increased, with a greater decrease in CGR realized at lower pre-Zn CGR

  16. A model for strain hardening, recovery, recrystallization and grain growth with applications to forming processes of nickel base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Riedel, Hermann, E-mail: [Fraunhofer Institute for Materials Mechanics, Wöhlerstr. 11, 79108 Freiburg (Germany); Svoboda, Jiri, E-mail: [Institute of Physics of Materials, Academy of Science of the Czech Republic, Zizkova 22, Brno (Czech Republic)


    An ensemble of n spherical grains is considered, each of which is characterized by its radius r{sub i} and by a hardening variable a{sub i}. The hardening variable obeys a Chaboche-type evolution equation with dynamic and static recovery. The grain growth law includes the usual contribution of the grain boundary energy, a term for the stored energy associated with the hardening variable, and the Zener pinning force exerted by particles on the migrating grain boundaries. New grains develop by recrystallization in grains whose stored energy density exceeds a critical value. The growth or shrinkage of the particles, which restrain grain boundary migration, obeys a thermodynamic/kinetic evolution equation. This set of first order differential equations for r{sub i}, a{sub i} and the particle radius is integrated numerically. Fictitious model parameters for a virtual nickel base alloy are used to demonstrate the properties and capabilities of the model. For a real nickel alloy, model parameters are adjusted using measured stress-strain curves, as well as recrystallized volume fractions and grain size distributions. Finally the model with adjusted parameters is applied to a forming process with complex temperature-strain rate histories.

  17. A fully integrated GaAs-based three-axis Hall magnetic sensor exploiting self-positioned strain released structures

    International Nuclear Information System (INIS)

    Todaro, Maria T; Sileo, Leonardo; Epifani, Gianmichele; Tasco, Vittorianna; Cingolani, Roberto; De Vittorio, Massimo; Passaseo, Adriana


    In this work, we demonstrate a fully integrated three-axis Hall magnetic sensor by exploiting microfabrication technologies applied to a GaAs-based heterostructure. This allows us to obtain, by the same process, three mutually orthogonal sensors: an in-plane Hall sensor and two out-of-plane Hall sensors. The micromachined devices consist of a two-dimensional electron gas AlGaAs/InGaAs/GaAs multilayer which represents the sensing structure, grown on the top of an InGaAs/GaAs strained bilayer. After the release from the substrate, the strained bilayer acts as a hinge for the multilayered structure allowing the out-of-plane self-positioning of devices. Both the in-plane and out-of-plane Hall sensors show a linear response versus the magnetic field with a sensitivity for current-biased devices higher than 1000 V A −1 T −1 , corresponding to an absolute sensitivity more than 0.05 V T −1 at 50 µA. Moreover, Hall voltage measurements, as a function of the mechanical angle for both in-plane and out-of-plane sensors, demonstrate the potential of such a device for measurements of the three vector components of a magnetic field

  18. DNA Fingerprinting of Lactobacillus crispatus Strain CTV-05 by Repetitive Element Sequence-Based PCR Analysis in a Pilot Study of Vaginal Colonization


    Antonio, May A. D.; Hillier, Sharon L.


    Lactobacillus crispatus is one of the predominant hydrogen peroxide (H2O2)-producing species found in the vagina and is under development as a probiotic for the treatment of bacterial vaginosis. In this study, we assessed whether DNA fingerprinting by repetitive element sequence-based PCR (rep-PCR) can be used to distinguish the capsule strain of L. crispatus (CTV-05) from other endogenous strains as well as other species of vaginal lactobacilli. Vaginal and rectal lactobacilli were identifie...

  19. Strain Sensors Based on Sandwich Structures of Crumpled Graphene for Structural Health Monitoring (United States)

    National Aeronautics and Space Administration — Space based systems are subject to varied stresses which induce damage leading to failure, therefore it is necessary to develop an onboard system to monitor...

  20. Mehanical Properties of Electron Beam Welded Joints in Thick Gage CA6NM Stainless Steel (United States)

    Sarafan, Sheida; Wanjara, Priti; Gholipour, Javad; Champliaud, Henri; Mathieu, Louis


    Design of hydroelectric turbine components requires high integrity welds (without detectable volumetric defects) in heavy gage sections of stainless steel materials, such as ASTM A743 grade CA6NM—a low carbon 13% Cr-4% Ni martensitic stainless steel that is manufactured in cast form. In this work, 90-mm-thick plates of CA6NM were joined using a single-pass autogenous electron beam (EB) welding process and the mechanical properties were evaluated in the as-welded condition to characterize the performance of the joints. The static tensile properties that were evaluated in two directions—transverse and longitudinal to the EB weld seam—demonstrated conformance of the joints with the requirements of the ASME Section IX standard. The Charpy impact energies of the EB welds—measured at -18 °C on samples with V-notch roots located in the fusion and heat-affected zones—met the minimum requirements of 27 J specified in ASME Section VIII standard. In addition, bend tests that were conducted on the entire weld cross section displayed no discontinuities on the tension side of the bent joints. Hence, the developed EB welding process was demonstrated to render high-performance joints and promises key advantages for industrialization, such as cost savings through reductions in consumable material, production time and labor intensity.

  1. Tubular gage for a liquid-metal-cooled fast breeder reactor

    International Nuclear Information System (INIS)

    Hutter, E.; Tuma, L.A.


    Spring-loaded plungers are arranged about a housing for insertion into a polygonal tube, one plunger for each side of the tube. Each plunger has a locking cam and sliding wedge mechanism which can overcome the spring force associated with the plunger and lock it in any position. The wedges are operated by a rod movable axially in the housing. Several housings with their associated plungers can be stacked. The stack is lowered into the polygonal tube with all of the plungers locked in a fully inward position. When the stack is in the tube, each wedge is moved to release its locking cam, allowing each of the plungers to spring outward against an inner side of the tube. Each housing will thus gage the internal dimensions of the tube at its elevation. The plungers are locked in position, the entire stack is rotated to bring the plungers into the corners described by the intersections of the flat sides, and the stack is removed from the tube whereupon the dimensions across opposite locked plungers may be read by a micrometer

  2. Flight Test Results from the Rake Airflow Gage Experiment on the F-15B Airplane (United States)

    Frederick, Michael A.; Ratnayake, Nalin A.


    The Rake Airflow Gage Experiment involves a flow-field survey rake that was flown on the Propulsion Flight Test Fixture at the NASA Dryden Flight Research Center using the Dryden F-15B research test bed airplane. The objective of this flight test was to ascertain the flow-field angularity, local Mach number profile, total pressure distortion, and dynamic pressure at the aerodynamic interface plane of the Channeled Centerbody Inlet Experiment. This new mixed-compression, supersonic inlet is planned for flight test in the near term. Knowledge of the flow-field characteristics at this location underneath the airplane is essential to flight test planning and computational modeling of the new inlet, anairplane, flying at a free-stream Mach number of 1.65 and a pressure altitude of 40,000 ft, would achieve the desired local Mach number for the future inlet flight test. Interface plane distortion levels of 2 percent and a local angle of attack of -2 deg were observed at this condition. Alternative flight conditions for future testing and an exploration of certain anomalous data also are provided.

  3. Ten years of real-time streamflow gaging of turkey creek - where we have been and where we are going (United States)

    Paul Conrads; Devendra Amatya


    The Turkey Creek watershed is a third-order coastal plain stream system draining an area of approximately 5,240 hectares of the Francis Marion National Forest and located about 37 miles northwest of Charleston near Huger, South Carolina. The U.S. Department of Agriculture (USDA) Forest Service maintained a streamflow gaging station on Turkey Creek from 1964 to 1981....

  4. Ductile failure analysis of defective API X65 pipes based on stress-modified fracture strain criterion

    International Nuclear Information System (INIS)

    Oh, Chang Kyun; Kim, Yun Jae; Baek, Jong Hyun; Kim, Young Pyo; Kim, Woo Sik


    A local failure criterion for the API X65 steel is applied to predict ductile failure of full-scale API X65 pipes with simulated corrosion and gouge defects under internal pressure. The local failure criterion is the stress-modified fracture strain for the API X65 steel as a function of the stress triaxiality (defined by the ratio of the hydrostatic stress to the effective stress). Based on detailed FE analyses with the proposed local failure criteria, burst pressures of defective pipes are estimated and compared with experimental data. The predicted burst pressures are in good agreement with experimental data. Noting that an assessment equation against the gouge defect is not yet available, parametric study is performed, from which a simple equation is proposed to predict burst pressure for API X65 pipes with gouge defects

  5. A comprehensive study of bubble inflation in vacuum-assisted thermoforming based on whole-field strain measurements (United States)

    Ayadi, A.; Lacrampe, M.-F.; Krawczak, P.


    This paper focuses on the potential use of stereo-DIC in thermoforming conditions to monitor large deformations of softened thermoplastic sheets posteriori to the sagging phenomenon. The study concerns HIPS sheets which are softened by the radiative heat-transfer mode then stretched by inflation of compressed-air for 1.5 s to form a large and quasi-spherical dome of 250 mm in diameter. While the bubble-inflation operation leads to large deformations of the softened sheet, it shows transitional geometrical instabilities due to the initial surface sagging. When the temperature-induced surface deformations are inaccessible by the stereoscopic system during the heating operation, the geometrical instabilities limit the identification of the reference of displacements which affects the accuracy of results based on image-correlation computations. To compare between the principal strains assessed from bubble-inflation tests conducted at different thermal conditions, a method for filtering these instabilities is developed in this study.

  6. Theoretical Conversions of Different Hardness and Tensile Strength for Ductile Materials Based on Stress-Strain Curves (United States)

    Chen, Hui; Cai, Li-Xun


    Based on the power-law stress-strain relation and equivalent energy principle, theoretical equations for converting between Brinell hardness (HB), Rockwell hardness (HR), and Vickers hardness (HV) were established. Combining the pre-existing relation between the tensile strength ( σ b ) and Hollomon parameters ( K, N), theoretical conversions between hardness (HB/HR/HV) and tensile strength ( σ b ) were obtained as well. In addition, to confirm the pre-existing σ b -( K, N) relation, a large number of uniaxial tensile tests were conducted in various ductile materials. Finally, to verify the theoretical conversions, plenty of statistical data listed in ASTM and ISO standards were adopted to test the robustness of the converting equations with various hardness and tensile strength. The results show that both hardness conversions and hardness-strength conversions calculated from the theoretical equations accord well with the standard data.

  7. Genome based analysis of type-I polyketide synthase and nonribosomal peptide synthetase gene clusters in seven strains of five representative Nocardia species. (United States)

    Komaki, Hisayuki; Ichikawa, Natsuko; Hosoyama, Akira; Takahashi-Nakaguchi, Azusa; Matsuzawa, Tetsuhiro; Suzuki, Ken-ichiro; Fujita, Nobuyuki; Gonoi, Tohru


    Actinobacteria of the genus Nocardia usually live in soil or water and play saprophytic roles, but they also opportunistically infect the respiratory system, skin, and other organs of humans and animals. Primarily because of the clinical importance of the strains, some Nocardia genomes have been sequenced, and genome sequences have accumulated. Genome sizes of Nocardia strains are similar to those of Streptomyces strains, the producers of most antibiotics. In the present work, we compared secondary metabolite biosynthesis gene clusters of type-I polyketide synthase (PKS-I) and nonribosomal peptide synthetase (NRPS) among genomes of representative Nocardia species/strains based on domain organization and amino acid sequence homology. Draft genome sequences of Nocardia asteroides NBRC 15531(T), Nocardia otitidiscaviarum IFM 11049, Nocardia brasiliensis NBRC 14402(T), and N. brasiliensis IFM 10847 were read and compared with published complete genome sequences of Nocardia farcinica IFM 10152, Nocardia cyriacigeorgica GUH-2, and N. brasiliensis HUJEG-1. Genome sizes are as follows: N. farcinica, 6.0 Mb; N. cyriacigeorgica, 6.2 Mb; N. asteroides, 7.0 Mb; N. otitidiscaviarum, 7.8 Mb; and N. brasiliensis, 8.9 - 9.4 Mb. Predicted numbers of PKS-I, NRPS, and PKS-I/NRPS hybrid clusters ranged between 4-11, 7-13, and 1-6, respectively, depending on strains, and tended to increase with increasing genome size. Domain and module structures of representative or unique clusters are discussed in the text. We conclude the following: 1) genomes of Nocardia strains carry as many PKS-I and NRPS gene clusters as those of Streptomyces strains, 2) the number of PKS-I and NRPS gene clusters in Nocardia strains varies substantially depending on species, and N. brasiliensis strains carry the largest numbers of clusters among the species studied, 3) the seven Nocardia strains studied in the present work have seven common PKS-I and/or NRPS clusters, some of whose products are yet to be studied

  8. Precipitation data for water years 1992 and 1993 from a network of nonrecording gages at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Ambos, D.S.; Flint, A.L.; Hevesi, J.A.


    This report presents precipitation data collected in a storage gage network at Yucca Mountain, Nevada, from October 1, 1991, to September 30, 1993. The measured values indicate total accumulated precipitation for specified time intervals approximately corresponding to separate storm events. Installation of a precipitation monitoring network was initiated in January 1990, and was continually expanded and upgraded throughout the period ending in September 1993. The final network included 3 different gage types for a total of 133 gages at 108 locations within the three drainages overlying the potential repository site. Measured precipitation indicated above average accumulations for water years 1992 and 1993 relative to the most recent estimate of 6.7 inches for long-term average annual precipitation over the area of the network. The total precipitation averaged over the network in 1992 was about 8.2 inches with a maximum of about 11.2 inches measured at borehole USW GA-1. The total precipitation averaged over the network in 1993 was about 10.3 inches with a maximum of about 12.1 inches at neutron-access borehole UE-25 UZN number-sign 4

  9. Efficiency of PCR-based methods in discriminating Bifidobacterium longum ssp. longum and Bifidobacterium longum ssp. infantis strains of human origin. (United States)

    Srůtková, Dagmar; Spanova, Alena; Spano, Miroslav; Dráb, Vladimír; Schwarzer, Martin; Kozaková, Hana; Rittich, Bohuslav


    Bifidobacterium longum is considered to play an important role in health maintenance of the human gastrointestinal tract. Probiotic properties of bifidobacterial isolates are strictly strain-dependent and reliable methods for the identification and discrimination of this species at both subspecies and strain levels are thus required. Differentiation between B. longum ssp. longum and B. longum ssp. infantis is difficult due to high genomic similarities. In this study, four molecular-biological methods (species- and subspecies-specific PCRs, random amplified polymorphic DNA (RAPD) method using 5 primers, repetitive sequence-based (rep)-PCR with BOXA1R and (GTG)(5) primers and amplified ribosomal DNA restriction analysis (ARDRA)) and biochemical analysis, were compared for the classification of 30 B. longum strains (28 isolates and 2 collection strains) on subspecies level. Strains originally isolated from the faeces of breast-fed healthy infants (25) and healthy adults (3) showed a high degree of genetic homogeneity by PCR with subspecies-specific primers and rep-PCR. When analysed by RAPD, the strains formed many separate clusters without any potential for subspecies discrimination. These methods together with arabionose/melezitose fermentation analysis clearly differentiated only the collection strains into B. longum ssp. longum and B. longum ssp. infantis at the subspecies level. On the other hand, ARDRA analysis differentiated the strains into the B. longum/infantis subspecies using the cleavage analysis of genus-specific amplicon with just one enzyme, Sau3AI. According to our results the majority of the strains belong to the B. longum ssp. infantis (75%). Therefore we suggest ARDRA using Sau3AI restriction enzyme as the first method of choice for distinguishing between B. longum ssp. longum and B. longum ssp. infantis. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Wearable strain sensors based on thin graphite films for human activity monitoring (United States)

    Saito, Takanari; Kihara, Yusuke; Shirakashi, Jun-ichi


    Wearable health-monitoring devices have attracted increasing attention in disease diagnosis and health assessment. In many cases, such devices have been prepared by complicated multistep procedures which result in the waste of materials and require expensive facilities. In this study, we focused on pyrolytic graphite sheet (PGS), which is a low-cost, simple, and flexible material, used as wearable devices for monitoring human activity. We investigated wearable devices based on PGSs for the observation of elbow and finger motions. The thin graphite films were fabricated by cutting small films from PGSs. The wearable devices were then made from the thin graphite films assembled on a commercially available rubber glove. The human motions could be observed using the wearable devices. Therefore, these results suggested that the wearable devices based on thin graphite films may broaden their application in cost-effective wearable electronics for the observation of human activity.

  11. Whole genome sequencing options for bacterial strain typing and epidemiologic analysis based on single nucleotide polymorphism versus gene-by-gene-based approaches. (United States)

    Schürch, A C; Arredondo-Alonso, S; Willems, R J L; Goering, R V


    Whole genome sequence (WGS)-based strain typing finds increasing use in the epidemiologic analysis of bacterial pathogens in both public health as well as more localized infection control settings. This minireview describes methodologic approaches that have been explored for WGS-based epidemiologic analysis and considers the challenges and pitfalls of data interpretation. Personal collection of relevant publications. When applying WGS to study the molecular epidemiology of bacterial pathogens, genomic variability between strains is translated into measures of distance by determining single nucleotide polymorphisms in core genome alignments or by indexing allelic variation in hundreds to thousands of core genes, assigning types to unique allelic profiles. Interpreting isolate relatedness from these distances is highly organism specific, and attempts to establish species-specific cutoffs are unlikely to be generally applicable. In cases where single nucleotide polymorphism or core gene typing do not provide the resolution necessary for accurate assessment of the epidemiology of bacterial pathogens, inclusion of accessory gene or plasmid sequences may provide the additional required discrimination. As with all epidemiologic analysis, realizing the full potential of the revolutionary advances in WGS-based approaches requires understanding and dealing with issues related to the fundamental steps of data generation and interpretation. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  12. Valence band structure and density of states effective mass model of biaxial tensile strained silicon based on k · p theory

    International Nuclear Information System (INIS)

    Kuang Qian-Wei; Liu Hong-Xia; Wang Shu-Long; Qin Shan-Shan; Wang Zhi-Lin


    After constructing a stress and strain model, the valence bands of in-plane biaxial tensile strained Si is calculated by k · p method. In the paper we calculate the accurate anisotropy valance bands and the splitting energy between light and heavy hole bands. The results show that the valance bands are highly distorted, and the anisotropy is more obvious. To obtain the density of states (DOS) effective mass, which is a very important parameter for device modeling, a DOS effective mass model of biaxial tensile strained Si is constructed based on the valance band calculation. This model can be directly used in the device model of metal—oxide semiconductor field effect transistor (MOSFET). It also a provides valuable reference for biaxial tensile strained silicon MOSFET design. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  13. A TaqMan-based real time PCR assay for specific detection and quantification of Xylella fastidiosa strains causing bacterial leaf scorch in oleander. (United States)

    Guan, Wei; Shao, Jonathan; Singh, Raghuwinder; Davis, Robert E; Zhao, Tingchang; Huang, Qi


    A TaqMan-based real-time PCR assay was developed for specific detection of strains of X. fastidiosa causing oleander leaf scorch. The assay uses primers WG-OLS-F1 and WG-OLS-R1 and the fluorescent probe WG-OLS-P1, designed based on unique sequences found only in the genome of oleander strain Ann1. The assay is specific, allowing detection of only oleander-infecting strains, not other strains of X. fastidiosa nor other plant-associated bacteria tested. The assay is also sensitive, with a detection limit of 10.4fg DNA of X. fastidiosa per reaction in vitro and in planta. The assay can also be applied to detect low numbers of X. fastidiosa in insect samples, or further developed into a multiplex real-time PCR assay to simultaneously detect and distinguish diverse strains of X. fastidiosa that may occupy the same hosts or insect vectors. Specific and sensitive detection and quantification of oleander strains of X. fastidiosa should be useful for disease diagnosis, epidemiological studies, management of oleander leaf scorch disease, and resistance screening for oleander shrubs. Published by Elsevier B.V.

  14. A rapid NMR-based method for discrimination of strain-specific cell wall teichoic acid structures reveals a third backbone type in Lactobacillus plantarum. (United States)

    Tomita, Satoru; Tanaka, Naoto; Okada, Sanae


    The lactic acid bacterium Lactobacillus plantarum is capable of producing strain-specific structures of cell wall teichoic acid (WTA), an anionic polysaccharide found in the Gram-positive bacterial cell wall. In this study, we established a rapid, NMR-based procedure to discriminate WTA structures in this species, and applied it to 94 strains of L. plantarum. Six previously reported glycerol- and ribitol-containing WTA subtypes were successfully identified from 78 strains, suggesting that these were the dominant structures. However, the level of structural variety differed markedly among bacterial sources, possibly reflecting differences in strain-level microbial diversity. WTAs from eight strains were not identified based on NMR spectra and were classified into three groups. Structural analysis of a partial degradation product of an unidentified WTA produced by strain TUA 1496L revealed that the WTA was 1-O-β-d-glucosylglycerol. Two-dimensional NMR analysis of the polymer structure showed phosphodiester bonds between C-3 and C-6 of the glycerol and glucose residues, suggesting a polymer structure of 3,6΄-linked poly(1-O-β-d-glucosyl-sn-glycerol phosphate). This is the third WTA backbone structure in L. plantarum, following 3,6΄-linked poly(1-O-α-d-glucosyl-sn-glycerol phosphate) and 1,5-linked poly(ribitol phosphate). © FEMS 2017. All rights reserved. For permissions, please e-mail:

  15. The epitaxial growth and interfacial strain study of VO{sub 2}/MgF{sub 2} (001) films by synchrotron based grazing incidence X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Fan, L.L. [Key Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province, Yancheng Institute of Technology, Yancheng 224051 (China); National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China); Chen, S. [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China); Liu, Q.H. [Science and Technology on Electro-optical Information Security Control Laboratory, Tianjin 300300 (China); Liao, G.M.; Chen, Y.L.; Ren, H. [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China); Zou, C.W., E-mail: [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China)


    High quality VO{sub 2} films with different thickness were epitaxially grown on MgF{sub 2} (001) substrates by oxide molecular beam epitaxy method. The evolution of interfacial strain was investigated by synchrotron based grazing incidence X-ray diffraction. By adjusting the incidence angles, the penetration depth of X-ray in VO{sub 2} film could be controlled and the thickness-depend lattice distortion in the epitaxial VO{sub 2} film was investigated. Due to the lattice mismatching, the pronounced tensile strain was observed in ultra-thin VO{sub 2} film. As the film thickness increasing, the interfacial strain relaxed gradually and became fully relaxed for thick VO{sub 2} films. Combined with the electric transport measurement, it was revealed that the phase transition temperature of ultra-thin VO{sub 2} film decreased greatly. The effect of interfacial strain induced phase transition modulation and the intrinsic mechanism was systematically discussed. - Highlights: • We prepared high quality VO{sub 2} epitaxial films on MgF{sub 2} (001) substrates by oxide molecular beam epitaxy method. • Synchrotron radiation grazing incidence X-ray diffraction was employed to detect evolution of strain along depth profile. • Based on a classic band structure model, the mechanism of strain controlled phase transition of VO{sub 2} was discussed.

  16. Field Strain Measurement on the Fiber Scale in Carbon Fiber Reinforced Polymers Using Global Finite-Element Based Digital Image Correlation

    KAUST Repository

    Tao, Ran


    is aimed to accurately measure the displacement and strain fields at the fiber-matrix scale in a cross-ply composite. First, the theories of both local subset-based digital image correlation (DIC) and global finite-element based DIC are outlined. Second, in

  17. Casting and stress-strain simulations of a cast ductile iron component using microstructure based mechanical behavior

    International Nuclear Information System (INIS)

    Olofsson, Jakob; Svensson, Ingvar L


    The industrial demand for increased component performance with concurrent reductions in component weight, development times and verifications using physical prototypes drives the need to use the full potential of casting and Finite Element Method (FEM) simulations to correctly predict the mechanical behavior of cast components in service. The mechanical behavior of the component is determined by the casting process, and factors as component geometry and casting process parameters are known to affect solidification and microstructure formation throughout the component and cause local variations in mechanical behavior as well as residual stresses. Though residual stresses are known to be an important factor in the mechanical behavior of the component, the importance of local mechanical behavior is not well established and the material is typically considered homogeneous throughout the component. This paper deals with the influence of solidification and solid state transformation on microstructure formation and the effect of local microstructure variations on the mechanical behavior of the cast component in service. The current work aims to investigate the coupling between simulation of solidification, microstructure and local variations in mechanical behavior and stress-strain simulation. This is done by performing several simulations of a ductile iron component using a recently developed simulation strategy, a closed chain of simulations for cast components, able to predict and describe the local variations in not only elastic but also plastic behavior throughout the component by using microstructural parameters determined by simulations of microstructural evolution in the component during the casting process. In addition the residual stresses are considered. The results show that the FEM simulation results are significantly affected by including microstructure based mechanical behavior. When the applied load is low and the component is subjected to stress levels

  18. A flexible strain gauge exhibiting reversible piezoresistivity based on an anisotropic magnetorheological polymer

    International Nuclear Information System (INIS)

    Mietta, José L; Martín Negri, R; Jorge, Guillermo


    A flexible, anisotropic and portable stress sensor (logarithmic reversible response between 40–350 kPa) was fabricated, in which i) the sensing material, ii) the electrical contacts and iii) the encapsulating material, were based on polydimethylsiloxane (PDMS) composites. The sensing material is a slide of an anisotropic magnetorheological elastomer (MRE), formed by dispersing silver-covered magnetite particles (Fe 3 O 4 @Ag) in PDMS and by curing in the presence of a uniform magnetic field. Thus, the MRE is a structure of electrically conducting pseudo-chains (needles) aligned in a specific direction, in which electrical conductivity increases when stress is exclusively applied in the direction of the needles. Electrical conductivity appears only between contact points that face each other at both sides of the MRE slide. An array of electrical contacts was implemented based on PDMS-silver paint metallic composites. The array was encapsulated with PDMS. Using Fe 3 O 4 superparamagnetic nanoparticles also opens up possibilities for a magnetic field sensor, due to the magnetoresistance effects. (paper)

  19. Straining electrode behavior and corrosion resistance of nickel base alloys in high temperature acidic solution

    International Nuclear Information System (INIS)

    Yamanaka, Kazuo


    Repassivation behavior and IGA resistance of nickel base alloys containing 0∼30 wt% chromium was investigated in high temperature acid sulfate solution. (1) The repassivation rate was increased with increasing chromium content. And so the amounts of charge caused by the metal dissolution were decreased with increasing chromium content. (2) Mill-annealed Alloy 600 suffered IGA at low pH environment below about 3.5 at the fixed potentials above the corrosion potential in 10%Na 2 SO 4 +H 2 SO 4 solution at 598K. On the other hand, thermally-treated Alloy 690 was hard to occur IGA at low pH environments which mill-annealed Alloy 600 occurred IGA. (3) It was considered that the reason, why nickel base alloys containing high chromium content such as Alloy 690 (60%Ni-30%Cr-10%Fe) had high IGA/SCC resistance in high temperature acidic solution containing sulfate ion, is due to both the promotion of the repassivation and the suppression of the film dissolution by the formation of the dense chromium oxide film

  20. Observation and quantification of water penetration into Strain Hardening Cement-based Composites (SHCC) with multiple cracks by means of neutron radiography

    International Nuclear Information System (INIS)

    Zhang, P.; Wittmann, F.H.; Zhao, T.J.; Lehmann, E.H.; Tian, L.; Vontobel, P.


    Durability of reinforced concrete structures has become a crucial issue with respect to economy, ecology and sustainability. One major reason for durability problems of concrete structures is the limited strain capacity of cement-based materials under imposed tensile stress. By adding PVA fibers, a new material named Strain Hardening Cement-based Composites (SHCC) with high strain capacity can be produced. Due to the formation of multiple micro-cracks, wide cracks can be avoided in SHCC under an imposed strain. The high strain capacity, however, is beneficial with respect to durability only if the multi-crack formation in SHCC does not lead to significantly increased water penetration. If water and aggressive chemical compounds such as chlorides and sulfates dissolved in water penetrate into the cement-based matrix and reach the steel reinforcement service-life of reinforced concrete structures will be reduced significantly. In this project, neutron radiography was applied to observe and quantify the process of water penetration into uncracked SHCC and after the multi-crack formation. In addition, water penetration into integral water repellent cracked and uncracked SHCC, which has been produced by adding a silane-based water repellent agent to the fresh SHCC mortar has been investigated. Results will be discussed with respect to durability.

  1. Strain sensors optimal placement for vibration-based structural health monitoring. The effect of damage on the initially optimal configuration (United States)

    Loutas, T. H.; Bourikas, A.


    We revisit the optimal sensor placement of engineering structures problem with an emphasis on in-plane dynamic strain measurements and to the direction of modal identification as well as vibration-based damage detection for structural health monitoring purposes. The approach utilized is based on the maximization of a norm of the Fisher Information Matrix built with numerically obtained mode shapes of the structure and at the same time prohibit the sensorization of neighbor degrees of freedom as well as those carrying similar information, in order to obtain a satisfactory coverage. A new convergence criterion of the Fisher Information Matrix (FIM) norm is proposed in order to deal with the issue of choosing an appropriate sensor redundancy threshold, a concept recently introduced but not further investigated concerning its choice. The sensor configurations obtained via a forward sequential placement algorithm are sub-optimal in terms of FIM norm values but the selected sensors are not allowed to be placed in neighbor degrees of freedom providing thus a better coverage of the structure and a subsequent better identification of the experimental mode shapes. The issue of how service induced damage affects the initially nominated as optimal sensor configuration is also investigated and reported. The numerical model of a composite sandwich panel serves as a representative aerospace structure upon which our investigations are based.

  2. Design and Development of a Flexible Strain Sensor for Textile Structures Based on a Conductive Polymer Composite

    Directory of Open Access Journals (Sweden)

    Claude Dufour


    Full Text Available The aim of this work is to develop a smart flexible sensor adapted to textile structures, able to measure their strain deformations. The sensors are “smart” because of their capacity to adapt to the specific mechanical properties of textile structures that are lightweight, highly flexible, stretchable, elastic, etc. Because of these properties, textile structures are continuously in movement and easily deformed, even under very low stresses. It is therefore important that the integration of a sensor does not modify their general behavior. The material used for the sensor is based on a thermoplastic elastomer (Evoprene/carbon black nanoparticle composite, and presents general mechanical properties strongly compatible with the textile substrate. Two preparation techniques are investigated: the conventional melt-mixing process, and the solvent process which is found to be more adapted for this particular application. The preparation procedure is fully described, namely the optimization of the process in terms of filler concentration in which the percolation theory aspects have to be considered. The sensor is then integrated on a thin, lightweight Nylon fabric, and the electromechanical characterization is performed to demonstrate the adaptability and the correct functioning of the sensor as a strain gauge on the fabric. A normalized relative resistance is defined in order to characterize the electrical response of the sensor. Finally, the influence of environmental factors, such as temperature and atmospheric humidity, on the sensor performance is investigated. The results show that the sensor’s electrical resistance is particularly affected by humidity. This behavior is discussed in terms of the sensitivity of the carbon black filler particles to the presence of water.

  3. Improved actuation strain of PDMS-based DEA materials chemically modified with softening agents (United States)

    Biedermann, Miriam; Blümke, Martin; Wegener, Michael; Krüger, Hartmut


    Dielectric elastomer actuators (DEAs) are smart materials that gained much in interest particularly in recent years. One active field of research is the improvement of their properties by modification of their structural framework. The object of this work is to improve the actuation properties of polydimethylsiloxane (PDMS)-based DEAs by covalent incorporation of mono-vinyl-terminated low-molecular PDMS chains into the PDMS network. These low-molecular units act as a kind of softener within the PDMS network. The loose chain ends interfere with the network formation and lower the network's density. PDMS films with up to 50wt% of low-molecular PDMS additives were manufactured and the chemical, mechanical, electrical, and electromechanical properties of these novel materials were investigated.

  4. Ultra-Sensitive Strain Sensor Based on Flexible Poly(vinylidene fluoride) Piezoelectric Film (United States)

    Lu, Kai; Huang, Wen; Guo, Junxiong; Gong, Tianxun; Wei, Xiongbang; Lu, Bing-Wei; Liu, Si-Yi; Yu, Bin


    A flexible 4 × 4 sensor array with 16 micro-scale capacitive units has been demonstrated based on flexible piezoelectric poly(vinylidene fluoride) (PVDF) film. The piezoelectricity and surface morphology of the PVDF were examined by optical imaging and piezoresponse force microscopy (PFM). The PFM shows phase contrast, indicating clear interface between the PVDF and electrode. The electro-mechanical properties show that the sensor exhibits excellent output response and an ultra-high signal-to-noise ratio. The output voltage and the applied pressure possess linear relationship with a slope of 12 mV/kPa. The hold-and-release output characteristics recover in less than 2.5 μs, demonstrating outstanding electro-mechanical response. Additionally, signal interference between the adjacent arrays has been investigated via theoretical simulation. The results show the interference reduces with decreasing pressure at a rate of 0.028 mV/kPa, highly scalable with electrode size and becoming insignificant for pressure level under 178 kPa.

  5. Bending of Euler-Bernoulli nanobeams based on the strain-driven and stress-driven nonlocal integral models: a numerical approach (United States)

    Oskouie, M. Faraji; Ansari, R.; Rouhi, H.


    Eringen's nonlocal elasticity theory is extensively employed for the analysis of nanostructures because it is able to capture nanoscale effects. Previous studies have revealed that using the differential form of the strain-driven version of this theory leads to paradoxical results in some cases, such as bending analysis of cantilevers, and recourse must be made to the integral version. In this article, a novel numerical approach is developed for the bending analysis of Euler-Bernoulli nanobeams in the context of strain- and stress-driven integral nonlocal models. This numerical approach is proposed for the direct solution to bypass the difficulties related to converting the integral governing equation into a differential equation. First, the governing equation is derived based on both strain-driven and stress-driven nonlocal models by means of the minimum total potential energy. Also, in each case, the governing equation is obtained in both strong and weak forms. To solve numerically the derived equations, matrix differential and integral operators are constructed based upon the finite difference technique and trapezoidal integration rule. It is shown that the proposed numerical approach can be efficiently applied to the strain-driven nonlocal model with the aim of resolving the mentioned paradoxes. Also, it is able to solve the problem based on the strain-driven model without inconsistencies of the application of this model that are reported in the literature.

  6. Study of lattice strain evolution during biaxial deformation of stainless steel using a finite element and fast Fourier transform based multi-scale approach

    International Nuclear Information System (INIS)

    Upadhyay, M.V.; Van Petegem, S.; Panzner, T.; Lebensohn, R.A.; Van Swygenhoven, H.


    A multi-scale elastic-plastic finite element and fast Fourier transform based approach is proposed to study lattice strain evolution during uniaxial and biaxial loading of stainless steel cruciform shaped samples. At the macroscale, finite element simulations capture the complex coupling between applied forces in the arms and gauge stresses induced by the cruciform geometry. The predicted gauge stresses are used as macroscopic boundary conditions to drive a mesoscale elasto-viscoplastic fast Fourier transform model, from which lattice strains are calculated for particular grain families. The calculated lattice strain evolution matches well with experimental values from in-situ neutron diffraction measurements and demonstrates that the spread in lattice strain evolution between different grain families decreases with increasing biaxial stress ratio. During equibiaxial loading, the model reveals that the lattice strain evolution in all grain families, and not just the 311 grain family, is representative of the polycrystalline response. A detailed quantitative analysis of the 200 and 220 grain family reveals that the contribution of elastic and plastic anisotropy to the lattice strain evolution significantly depends on the applied stress ratio.

  7. Absolute Enumeration of Probiotic Strains Lactobacillus acidophilus NCFM® and Bifidobacterium animalis subsp. lactis Bl-04® via Chip-Based Digital PCR

    Directory of Open Access Journals (Sweden)

    Sarah J. Z. Hansen


    Full Text Available The current standard for enumeration of probiotics to obtain colony forming units by plate counts has several drawbacks: long time to results, high variability and the inability to discern between bacterial strains. Accurate probiotic cell counts are important to confirm the delivery of a clinically documented dose for its associated health benefits. A method is described using chip-based digital PCR (cdPCR to enumerate Bifidobacterium animalis subsp. lactis Bl-04 and Lactobacillus acidophilus NCFM both as single strains and in combination. Primers and probes were designed to differentiate the target strains against other strains of the same species using known single copy, genetic differences. The assay was optimized to include propidium monoazide pre-treatment to prevent amplification of DNA associated with dead probiotic cells as well as liberation of DNA from cells with intact membranes using bead beating. The resulting assay was able to successfully enumerate each strain whether alone or in multiplex. The cdPCR method had a 4 and 5% relative standard deviation (RSD for Bl-04 and NCFM, respectively, making it more precise than plate counts with an industry accepted RSD of 15%. cdPCR has the potential to replace traditional plate counts because of its precision, strain specificity and the ability to obtain results in a matter of hours.

  8. An elasto-plastic self-consistent model with hardening based on dislocation density, twinning and de-twinning: Application to strain path changes in HCP metals

    International Nuclear Information System (INIS)

    Zecevic, Milovan; Knezevic, Marko; Beyerlein, Irene J.; Tomé, Carlos N.


    In this work, we develop a polycrystal mean-field constitutive model based on an elastic–plastic self-consistent (EPSC) framework. In this model, we incorporate recently developed subgrain models for dislocation density evolution with thermally activated slip, twin activation via statistical stress fluctuations, reoriented twin domains within the grain and associated stress relaxation, twin boundary hardening, and de-twinning. The model is applied to a systematic set of strain path change tests on pure beryllium (Be). Under the applied deformation conditions, Be deforms by multiple slip modes and deformation twinning and thereby provides a challenging test for model validation. With a single set of material parameters, determined using the flow-stress vs. strain responses during monotonic testing, the model predicts well the evolution of texture, lattice strains, and twinning. With further analysis, we demonstrate the significant influence of internal residual stresses on (1) the flow stress drop when reloading from one path to another, (2) deformation twin activation, (3) de-twinning during a reversal strain path change, and (4) the formation of additional twin variants during a cross-loading sequence. The model presented here can, in principle, be applied to other metals, deforming by multiple slip and twinning modes under a wide range of temperature, strain rate, and strain path conditions

  9. Use of micro-CT-based finite element analysis to accurately quantify peri-implant bone strains: a validation in rat tibiae. (United States)

    Torcasio, Antonia; Zhang, Xiaolei; Van Oosterwyck, Hans; Duyck, Joke; van Lenthe, G Harry


    Although research has been addressed at investigating the effect of specific loading regimes on bone response around the implant, a precise quantitative understanding of the local mechanical response close to the implant site is still lacking. This study was aimed at validating micro-CT-based finite element (μFE) models to assess tissue strains after implant placement in a rat tibia. Small implants were inserted at the medio-proximal site of 8 rat tibiae. The limbs were subjected to axial compression loading; strain close to the implant was measured by means of strain gauges. Specimen-specific μFE models were created and analyzed. For each specimen, 4 different models were created corresponding to different representations of the bone-implant interface: bone and implant were assumed fully osseointegrated (A); a low stiffness interface zone was assumed with thickness of 40 μm (B), 80 μm (C), and 160 μm (D). In all cases, measured and computational strains correlated highly (R (2) = 0.95, 0.92, 0.93, and 0.95 in A, B, C, and D, respectively). The averaged calculated strains were 1.69, 1.34, and 1.15 times higher than the measured strains for A, B, and C, respectively, and lower than the experimental strains for D (factor = 0.91). In conclusion, we demonstrated that specimen-specific FE analyses provide accurate estimates of peri-implant bone strains in the rat tibia loading model. Further investigations of the bone-implant interface are needed to quantify implant osseointegration.

  10. Investigation on seasonal variation of thermal-induced strain in flexible pavements based on field and laboratory measurements

    Directory of Open Access Journals (Sweden)

    Simita Biswas


    Full Text Available Pavement temperature variation has a large influence on the structural response of flexible pavements. Daily and seasonal temperature fluctuation causes expansion and contraction of pavement material, which then leads to the generation of thermal strain. In this study, field observation and laboratory tests were conducted to investigate seasonal variation of thermal-induced strain in flexible pavement. Field observations were conducted at the Integrated Road Research Facility (IRRF’s test road in Edmonton, Alberta, Canada, which is fully equipped with structural and environmental monitoring instruments. The main objective of the field study was to compare the variation of thermal-induced strain in warm and cold seasons. Field results indicated that thermal-induced strain is 1.4–2.0 times greater in cold seasons than in warm seasons following the same pavement temperature variations; however, strain generation rate was greater in warm seasons. Laboratory testing of asphalt slab and cylindrical samples produced comparable ratios. Moreover, field observation and laboratory testing showed a similar trend of temperature and thermal strain variations. Keywords: Thermal-induced strain, Asphalt strain gauge, Field observation, Flexible pavement, Laboratory testing, Seasonal variation

  11. Strain-induced collagen organization at the micro-level in fibrin-based engineered tissue constructs

    NARCIS (Netherlands)

    Jonge, de N.; Kanters, F.M.W.; Baaijens, F.P.T.; Bouten, C.V.C.


    Full understanding of strain-induced collagen organization in complex tissue geometries to create tissues with predefined collagen architecture has not been achieved. This is mainly due to our limited knowledge of collagen remodeling in developing tissues. Here we investigate strain-induced collagen

  12. Temperature Compensated Strain Sensor Based on Cascaded Sagnac Interferometers and All-Solid Birefringent Hybrid Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Gu, Bobo; Yuan, Wu; He, Sailing


    We demonstrate a temperature compensated strain sensor with two cascaded Sagnac interferometers, that provide strain sensing and temperature compensation, respectively. The Sagnac interferometers use an all-solid hybrid photonic crystal fiber with stress-induced birefringence. The stress-induced ...

  13. Genomotyping of Pseudomonas putida strains using P. putida KT2440-based high-density DNA microarrays: Implications for transcriptomics studies

    NARCIS (Netherlands)

    Ballerstedt, H.; Volkers, R.J.M.; Mars, A.E.; Hallsworth, J.E.; Santos, V.A.M.D.; Puchalka, J.; Duuren, J. van; Eggink, G.; Timmis, K.N.; Bont, J.A.M. de; Wery, J.


    Pseudomonas putida KT2440 is the only fully sequenced P. putida strain. Thus, for transcriptomics and proteomics studies with other P. putida strains, the P. putida KT2440 genomic database serves as standard reference. The utility of KT2440 whole-genome, high-density oligonucleotide microarrays for

  14. A method of creep damage summation based on accumulated strain for the assessment of creep-fatigue endurance

    International Nuclear Information System (INIS)

    Hales, R.


    A method of combining long term creep data with relatively short term mechanical behaviour to provide an estimate of creep-fatigue endurance is presented. It is proposed that the creep-fatigue effect in high temperature cyclic deformation is governed by a difference in strain rate around the cycle and the associated variation in ductility with strain rate. (author)

  15. Patterned, highly stretchable and conductive nanofibrous PANI/PVDF strain sensors based on electrospinning and in situ polymerization (United States)

    Yu, Gui-Feng; Yan, Xu; Yu, Miao; Jia, Meng-Yang; Pan, Wei; He, Xiao-Xiao; Han, Wen-Peng; Zhang, Zhi-Ming; Yu, Liang-Min; Long, Yun-Ze


    A facile fabrication strategy via electrospinning and followed by in situ polymerization to fabricate a patterned, highly stretchable, and conductive polyaniline/poly(vinylidene fluoride) (PANI/PVDF) nanofibrous membrane is reported. Owing to the patterned structure, the nanofibrous PANI/PVDF strain sensor can detect a strain up to 110%, for comparison, which is 2.6 times higher than the common nonwoven PANI/PVDF mat and much larger than the previously reported values (usually less than 15%). Meanwhile, the conductivity of the patterned strain sensor shows a linear response to the applied strain in a wide range from 0% to about 85%. Additionally, the patterned PANI/PVDF strain sensor can completely recover to its original electrical and mechanical values within a strain range of more than 22%, and exhibits good durability over 10 000 folding-unfolding tests. Furthermore, the strain sensor also can be used to detect finger motion. The results demonstrate promising application of the patterned nanofibrous membrane in flexible electronic fields.A facile fabrication strategy via electrospinning and followed by in situ polymerization to fabricate a patterned, highly stretchable, and conductive polyaniline/poly(vinylidene fluoride) (PANI/PVDF) nanofibrous membrane is reported. Owing to the patterned structure, the nanofibrous PANI/PVDF strain sensor can detect a strain up to 110%, for comparison, which is 2.6 times higher than the common nonwoven PANI/PVDF mat and much larger than the previously reported values (usually less than 15%). Meanwhile, the conductivity of the patterned strain sensor shows a linear response to the applied strain in a wide range from 0% to about 85%. Additionally, the patterned PANI/PVDF strain sensor can completely recover to its original electrical and mechanical values within a strain range of more than 22%, and exhibits good durability over 10 000 folding-unfolding tests. Furthermore, the strain sensor also can be used to detect finger

  16. Strain rate behavior of magnetorheological materials

    International Nuclear Information System (INIS)

    Seminuk, Kenneth; Joshi, Vasant; Gump, Jared; Stoltz, Chad; Forbes, Jerry


    Strain rate response of two Hydroxyl-terminated Polybutadiene/ Iron (HTPB/Fe) compositions under electromagnetic fields has been investigated using a Split Hopkinson Pressure bar arrangement equipped with aluminum bars. Two HTPB/Fe compositions were developed, the first without plasticizer and the second containing plasticizer. Samples were tested with and without the application of a 0.01 Tesla magnetic field. Strain gauge data taken from the Split Hopkinson Pressure Bar has been used to determine the extent of change in mechanical properties by inducing a mild electromagnetic field onto each sample. Raw data from strain gages was processed using commercial software (Signo) and Excel spreadsheet. It is of particular interest to determine whether the mechanical properties of binder systems can be manipulated by adding ferrous or Magnetostrictive particulates. Data collected from the Split Hopkinson Pressure bar indicate changes in the Mechanical Stress-Strain curves and suggest that the impedance of a binder system can be altered by means of a magnetic field.

  17. Performance of a Distributed Simultaneous Strain and Temperature Sensor Based on a Fabry-Perot Laser Diode and a Dual-Stage FBG Optical Demultiplexer

    Directory of Open Access Journals (Sweden)

    Shinwon Kang


    Full Text Available A simultaneous strain and temperature measurement method using a Fabry-Perot laser diode (FP-LD and a dual-stage fiber Bragg grating (FBG optical demultiplexer was applied to a distributed sensor system based on Brillouin optical time domain reflectometry (BOTDR. By using a Kalman filter, we improved the performance of the FP-LD based OTDR, and decreased the noise using the dual-stage FBG optical demultiplexer. Applying the two developed components to the BOTDR system and using a temperature compensating algorithm, we successfully demonstrated the simultaneous measurement of strain and temperature distributions under various experimental conditions. The observed errors in the temperature and strain measured using the developed sensing system were 0.6 °C and 50 με, and the spatial resolution was 1 m, respectively.

  18. Performance of a distributed simultaneous strain and temperature sensor based on a Fabry-Perot laser diode and a dual-stage FBG optical demultiplexer. (United States)

    Kim, Suhwan; Kwon, Hyungwoo; Yang, Injae; Lee, Seungho; Kim, Jeehyun; Kang, Shinwon


    A simultaneous strain and temperature measurement method using a Fabry-Perot laser diode (FP-LD) and a dual-stage fiber Bragg grating (FBG) optical demultiplexer was applied to a distributed sensor system based on Brillouin optical time domain reflectometry (BOTDR). By using a Kalman filter, we improved the performance of the FP-LD based OTDR, and decreased the noise using the dual-stage FBG optical demultiplexer. Applying the two developed components to the BOTDR system and using a temperature compensating algorithm, we successfully demonstrated the simultaneous measurement of strain and temperature distributions under various experimental conditions. The observed errors in the temperature and strain measured using the developed sensing system were 0.6 °C and 50 με, and the spatial resolution was 1 m, respectively.

  19. Eraser-based eco-friendly fabrication of a skin-like large-area matrix of flexible carbon nanotube strain and pressure sensors. (United States)

    Sahatiya, Parikshit; Badhulika, Sushmee


    This paper reports a new type of electronic, recoverable skin-like pressure and strain sensor, produced on a flexible, biodegradable pencil-eraser substrate and fabricated using a solvent-free, low-cost and energy efficient process. Multi-walled carbon nanotube (MWCNT) film, the strain sensing element, was patterned on pencil eraser with a rolling pin and a pre-compaction mechanical press. This induces high interfacial bonding between the MWCNTs and the eraser substrate, which enables the sensor to achieve recoverability under ambient conditions. The eraser serves as a substrate for strain sensing, as well as acting as a dielectric for capacitive pressure sensing, thereby eliminating the dielectric deposition step, which is crucial in capacitive-based pressure sensors. The strain sensing transduction mechanism is attributed to the tunneling effect, caused by the elastic behavior of the MWCNTs and the strong mechanical interlock between MWCNTs and the eraser substrate, which restricts slippage of MWCNTs on the eraser thereby minimizing hysteresis. The gauge factor of the strain sensor was calculated to be 2.4, which is comparable to and even better than most of the strain and pressure sensors fabricated with more complex designs and architectures. The sensitivity of the capacitive pressure sensor was found to be 0.135 MPa -1 .To demonstrate the applicability of the sensor as artificial electronic skin, the sensor was assembled on various parts of the human body and corresponding movements and touch sensation were monitored. The entire fabrication process is scalable and can be integrated into large areas to map spatial pressure distributions. This low-cost, easily scalable MWCNT pin-rolled eraser-based pressure and strain sensor has huge potential in applications such as artificial e-skin in flexible electronics and medical diagnostics, in particular in surgery as it provides high spatial resolution without a complex nanostructure architecture.

  20. Strain measurements of nuclear power plant steam generator antiseismic supports

    International Nuclear Information System (INIS)

    Kulichevsky, R.


    The nuclear power plants steam generators have different types of structural supports. One of these types are the antiseismic supports, which are intended to be under stress only if a seismic event takes place. Nevertheless, the antiseismic supports lugs, that are welded to the steam generator vessel, are subjected to thermal fatigue because of the temperature cycles related with the shut down and start up operations performed during the life of the nuclear power plant. In order to evaluate the stresses that the lugs are subjected to, several strain gages were welded on two supports lugs, positioned at two heights of one of the Embalse nuclear power plant steam generators. In this paper, the instrumentation used and the strain measurements obtained during two start up operations are presented. The influence of the plant start up operation parameters on the lugs strain evolution is also analyzed. (author) [es

  1. Effect of axial strain on the critical current of Ag-sheathed Bi-based superconductors in magnetic fields up to 25 T

    International Nuclear Information System (INIS)

    Ekin, J.W.; Finnemore, D.K.; Li, Q.; Tenbrink, J.; Carter, W.


    The irreversible strain limit ε irrev for the onset of permanent axial strain damage to Ag-sheathed Bi 2 Sr 2 Ca 1 Cu 2 O 8+x and Bi 2 Sr 2 Ca 2 Cu 3 O 10+x superconductors has been measured to be in the range of 0.2%--0.35%. This strain damage onset is about an order of magnitude higher than for bulk sintered Y-, Bi-, or Tl-based superconductors and is approaching practical values for magnet design. The measurements show that the value of ε irrev is not dependent on magnetic field, nor does the critical current depend on strain below ε irrev at least up to 25 T at 4.2 K. Both of these factors indicate that the observed strain effect in Ag-sheathed Bi-based superconductors is not intrinsic to the superconductor material. Rather, the effect is extrinsic and arises from superconductor fracture. Thus, the damage onset is amenable to further enhancement. Indeed, the data suggest that subdividing the superconductor into fine filaments or adding Ag to the superconductor powder prior to processing significantly enhances the damage threshold ε irrev to above 0.6%

  2. The application of a 3 dimensional image scanner to the strain measurement

    International Nuclear Information System (INIS)

    Mazda, Taiji; Ogawa, Hiroshi; Suzuki, Michiaki; Nakano, Yasuo.


    A large strain measuring method for a laminated seismic isolation rubber, which will be introduced to reactor buildings of the Demonstration Fast Breeder Reactor (DFBR), was developed. With using strain gages, it is difficult to measure the large strain under the large displacement condition. With using the optical instruments, it is also impossible to measure the strain of a 3 dimensional object. We developed a new measuring method in which strain is calculated from a 3 dimensional deformation with using a 3 dimensional image scanner. This method is noncontact measuring method, and it can measure the strain of a 3 dimensional object under the large deformation. This work is one part of 'The Development of FBR Seismic Isolation system' operated by Central Research Institute of Electric Power Industry. (author)

  3. Strain monitoring of cement-based materials with embedded polyvinyl alcohol - carbon nanotube (PVA-CNT fibers

    Directory of Open Access Journals (Sweden)

    Zoi S. Metaxa


    Full Text Available This article investigates the possibility of exploiting innovative polyvinyl alcohol fibers reinforced with carbon nanotubes (PVA-CNT fiber as a strain sensor in cement mortars used in the restoration of Cultural Heritage Monuments. Two types of PVA-CNT fibers were embedded in the matrix at a short distance from the bottom of the beam and their readings were correlated with traditional sensors, e.g. strain gauges and Fiber Optic Bragg Gratings. The Electrical Resistance Change (ERC of the embedded PVA-CNT fiber was in-situ monitored during four-point bending mechanical tests. For the case of coated PVA-CNT fiber, a linear correlation of the applied strain at the bottom surface of the specimen along with ERC values of the fiber was noticed for the low strain regime. For the case of incremental increasing loading – unloading loops, the coated and annealed PVA-CNT fiber gave the best results either as embedded or as ‘surface attached’ sensor that exhibited linear correlation of ERC with applied strain for the low applied strain regime as well as hysteresis loops during unloading. The article discusses their high potential to be exploited as strain/damage sensor in applications of civil engineering as well as in restoration of Monuments of Cultural Heritage.

  4. Simulation of daily streamflows at gaged and ungaged locations within the Cedar River Basin, Iowa, using a Precipitation-Runoff Modeling System model (United States)

    Christiansen, Daniel E.


    The U.S. Geological Survey, in cooperation with the Iowa Department of Natural Resources, conducted a study to examine techniques for estimation of daily streamflows using hydrological models and statistical methods. This report focuses on the use of a hydrologic model, the U.S. Geological Survey's Precipitation-Runoff Modeling System, to estimate daily streamflows at gaged and ungaged locations. The Precipitation-Runoff Modeling System is a modular, physically based, distributed-parameter modeling system developed to evaluate the impacts of various combinations of precipitation, climate, and land use on surface-water runoff and general basin hydrology. The Cedar River Basin was selected to construct a Precipitation-Runoff Modeling System model that simulates the period from January 1, 2000, to December 31, 2010. The calibration period was from January 1, 2000, to December 31, 2004, and the validation periods were from January 1, 2005, to December 31, 2010 and January 1, 2000 to December 31, 2010. A Geographic Information System tool was used to delineate the Cedar River Basin and subbasins for the Precipitation-Runoff Modeling System model and to derive parameters based on the physical geographical features. Calibration of the Precipitation-Runoff Modeling System model was completed using a U.S. Geological Survey calibration software tool. The main objective of the calibration was to match the daily streamflow simulated by the Precipitation-Runoff Modeling System model with streamflow measured at U.S. Geological Survey streamflow gages. The Cedar River Basin daily streamflow model performed with a Nash-Sutcliffe efficiency ranged from 0.82 to 0.33 during the calibration period, and a Nash-Sutcliffe efficiency ranged from 0.77 to -0.04 during the validation period. The Cedar River Basin model is meeting the criteria of greater than 0.50 Nash-Sutcliffe and is a good fit for streamflow conditions for the calibration period at all but one location, Austin, Minnesota

  5. A new macroscopically anisotropic pressure dependent yield function for metal matrix composite based on strain gradient plasticity for the microstructure

    DEFF Research Database (Denmark)

    Azizi, Reza; Legarth, Brian Nyvang; Niordson, Christian Frithiof


    Metal matrix composites with long aligned elastic fibers are studied using an energetic rate independent strain gradient plasticity theory with an isotropic pressure independent yield function at the microscale. The material response is homogenized to obtain a conventional macroscopic model...... is investigated numerically using a unit cell model with periodic boundary conditions containing a single fiber deformed under generalized plane strain conditions. The homogenized response can be modeled by conventional plasticity with an anisotropic yield surface and a free energy depending on plastic strain...

  6. Selection of microalgae and cyanobacteria strains for bicarbonate-based integrated carbon capture and algae production system. (United States)

    Chi, Zhanyou; Elloy, Farah; Xie, Yuxiao; Hu, Yucai; Chen, Shulin


    Using microalgae to capture CO2 from flue gas is an ideal way to reduce CO2 emission, but this is challenged by the high cost of carbon capture and transportation. To address this problem, a bicarbonate-based integrated carbon capture and algae production system (BICCAPS) has been proposed, in which bicarbonate is used for algae culture, and the regenerated carbonate from this process can be used to capture more CO2. High-concentration bicarbonate is obligate for the BICCAPS. Thus, different strains of microalgae and cyanobacteria were tested in this study for their capability to grow in high-concentration NaHCO3. The highest NaHCO3 concentrations they are tolerant to were determined as 0.30 M for Synechocystis sp. PCC6803, 0.60 M for Cyanothece sp., 0.10 M for Chlorella sorokiniana, 0.60 M for Dunaliella salina, and 0.30 M for Dunaliella viridis and Dunaliella primolecta. In further study, biomass production from culture of D. primolecta in an Erlenmeyer flask with either 0.30 M NaHCO3 or 2 % CO2 bubbling was compared, and no significant difference was detected. This indicates BICCAPS can reach the same biomass productivity as regular CO2 bubbling culture, and it is promising for future application.

  7. Sampling optimization for high-speed weigh-in-motion measurements using in-pavement strain-based sensors

    International Nuclear Information System (INIS)

    Zhang, Zhiming; Huang, Ying; Bridgelall, Raj; Palek, Leonard; Strommen, Robert


    Weigh-in-motion (WIM) measurement has been widely used for weight enforcement, pavement design, freight management, and intelligent transportation systems to monitor traffic in real-time. However, to use such sensors effectively, vehicles must exit the traffic stream and slow down to match their current capabilities. Hence, agencies need devices with higher vehicle passing speed capabilities to enable continuous weight measurements at mainline speeds. The current practices for data acquisition at such high speeds are fragmented. Deployment configurations and settings depend mainly on the experiences of operation engineers. To assure adequate data, most practitioners use very high frequency measurements that result in redundant samples, thereby diminishing the potential for real-time processing. The larger data memory requirements from higher sample rates also increase storage and processing costs. The field lacks a sampling design or standard to guide appropriate data acquisition of high-speed WIM measurements. This study develops the appropriate sample rate requirements as a function of the vehicle speed. Simulations and field experiments validate the methods developed. The results will serve as guidelines for future high-speed WIM measurements using in-pavement strain-based sensors. (paper)

  8. ReacKnock: identifying reaction deletion strategies for microbial strain optimization based on genome-scale metabolic network.

    Directory of Open Access Journals (Sweden)

    Zixiang Xu

    Full Text Available Gene knockout has been used as a common strategy to improve microbial strains for producing chemicals. Several algorithms are available to predict the target reactions to be deleted. Most of them apply mixed integer bi-level linear programming (MIBLP based on metabolic networks, and use duality theory to transform bi-level optimization problem of large-scale MIBLP to single-level programming. However, the validity of the transformation was not proved. Solution of MIBLP depends on the structure of inner problem. If the inner problem is continuous, Karush-Kuhn-Tucker (KKT method can be used to reformulate the MIBLP to a single-level one. We adopt KKT technique in our algorithm ReacKnock to attack the intractable problem of the solution of MIBLP, demonstrated with the genome-scale metabolic network model of E. coli for producing various chemicals such as succinate, ethanol, threonine and etc. Compared to the previous methods, our algorithm is fast, stable and reliable to find the optimal solutions for all the chemical products tested, and able to provide all the alternative deletion strategies which lead to the same industrial objective.

  9. Strain compensation in InGaN-based multiple quantum wells using AlGaN interlayers

    Directory of Open Access Journals (Sweden)

    Syed Ahmed Al Muyeed


    Full Text Available Data are presented on strain compensation in InGaN-based multiple quantum wells (MQW using AlGaN interlayers (ILs. The MQWs consist of five periods of InxGa1-xN/AlyGa1-yN/GaN emitting in the green (λ ∼ 535 nm ± 15 nm, and the AlyGa1-yN IL has an Al composition of y = 0.42. The IL is varied from 0 - 2.1 nm, and the relaxation of the MQW with respect to the GaN template layer varies with IL thickness as determined by reciprocal space mapping about the (202¯5 reflection. The minimum in the relaxation occurs at an interlayer thickness of 1 nm, and the MQW is nearly pseudomorphic to GaN. Both thinner and thicker ILs display increased relaxation. Photoluminescence data shows enhanced spectral intensity and narrower full width at half maximum for the MQW with 1 nm thick ILs, which is a product of pseudomorphic layers with lower defect density and non-radiative recombination.

  10. Sampling optimization for high-speed weigh-in-motion measurements using in-pavement strain-based sensors (United States)

    Zhang, Zhiming; Huang, Ying; Bridgelall, Raj; Palek, Leonard; Strommen, Robert


    Weigh-in-motion (WIM) measurement has been widely used for weight enforcement, pavement design, freight management, and intelligent transportation systems to monitor traffic in real-time. However, to use such sensors effectively, vehicles must exit the traffic stream and slow down to match their current capabilities. Hence, agencies need devices with higher vehicle passing speed capabilities to enable continuous weight measurements at mainline speeds. The current practices for data acquisition at such high speeds are fragmented. Deployment configurations and settings depend mainly on the experiences of operation engineers. To assure adequate data, most practitioners use very high frequency measurements that result in redundant samples, thereby diminishing the potential for real-time processing. The larger data memory requirements from higher sample rates also increase storage and processing costs. The field lacks a sampling design or standard to guide appropriate data acquisition of high-speed WIM measurements. This study develops the appropriate sample rate requirements as a function of the vehicle speed. Simulations and field experiments validate the methods developed. The results will serve as guidelines for future high-speed WIM measurements using in-pavement strain-based sensors.

  11. Damage detection methodology under variable load conditions based on strain field pattern recognition using FBGs, nonlinear principal component analysis, and clustering techniques (United States)

    Sierra-Pérez, Julián; Torres-Arredondo, M.-A.; Alvarez-Montoya, Joham


    Structural health monitoring consists of using sensors integrated within structures together with algorithms to perform load monitoring, damage detection, damage location, damage size and severity, and prognosis. One possibility is to use strain sensors to infer structural integrity by comparing patterns in the strain field between the pristine and damaged conditions. In previous works, the authors have demonstrated that it is possible to detect small defects based on strain field pattern recognition by using robust machine learning techniques. They have focused on methodologies based on principal component analysis (PCA) and on the development of several unfolding and standardization techniques, which allow dealing with multiple load conditions. However, before a real implementation of this approach in engineering structures, changes in the strain field due to conditions different from damage occurrence need to be isolated. Since load conditions may vary in most engineering structures and promote significant changes in the strain field, it is necessary to implement novel techniques for uncoupling such changes from those produced by damage occurrence. A damage detection methodology based on optimal baseline selection (OBS) by means of clustering techniques is presented. The methodology includes the use of hierarchical nonlinear PCA as a nonlinear modeling technique in conjunction with Q and nonlinear-T 2 damage indices. The methodology is experimentally validated using strain measurements obtained by 32 fiber Bragg grating sensors bonded to an aluminum beam under dynamic bending loads and simultaneously submitted to variations in its pitch angle. The results demonstrated the capability of the methodology for clustering data according to 13 different load conditions (pitch angles), performing the OBS and detecting six different damages induced in a cumulative way. The proposed methodology showed a true positive rate of 100% and a false positive rate of 1.28% for a

  12. Effect of out-of-plane specimen movement on strain measurement using digital-image-correlation-based video measurement in 2D and 3D

    DEFF Research Database (Denmark)

    Poling, Joel; Desai, Niranjan; Fischer, Gregor


    This study determined the effect of specimen out-of-plane movement relative to the sensor, on the accuracy of strains measured made applying 2D and 3D measurement approaches employing the state-of-the-art digital-image-correlation (DIC)-based tool iMETRUM. DIC provides a convenient and inexpensive...

  13. Log in and breathe out: internet-based recovery training for sleepless employees with work-related strain - results of a randomized controlled trial

    NARCIS (Netherlands)

    Thiart, H.; Lehr, D.; Ebert, D.D.; Berking, M.; Riper, H.


    Objectives The primary purpose of this randomized controlled trial (RCT) was to evaluate the efficacy of a guided internet-based recovery training for employees who suffer from both work-related strain and sleep problems (GET.ON Recovery). The recovery training consisted of six lessons, employing

  14. A quantitative approach to study the effect of local texture and heterogeneous plastic strain on the deformation micromechanism in RR1000 nickel-based superalloy

    International Nuclear Information System (INIS)

    Birosca, S.; Di Gioacchino, F.; Stekovic, S.; Hardy, M.


    In a weakly textured material with relatively pore-free and homogeneous microstructure, the local texture can influence primary crack propagation and secondary crack initiation, depending on specific microtexture cluster size. Moreover, the plastic strain assessment and strain quantity within individual grains are essential for understanding the material susceptibility to crack initiation and propagation at various loading conditions and temperature ranges. In the current study, electron backscatter diffraction (EBSD) is applied to measure the plastic strain present in RR1000 nickel-based superalloy microstructure following thermo-mechanical fatigue tests. The EBSD plastic strain measurements are evaluated to identify the distinctive deformation mode within individual grains. It was evident from the overall statistical analyses carried out for over 2000 grains that cube (〈0 0 1〉//loading direction) and near cube orientations (φ 1 , Φ, φ 2 : 0, 0–15, 0) behaved as “soft” grains with a high Schmid factor and contained low geometrically necessary dislocation (GND) density as a result of low strain hardening at the early stage of deformation for such grains. The near cube orientation (typically φ 1 , Φ, φ 2 : 0, 9, 0) was the softest orientation among the cube family. While the brass grains (〈1 1 1〉//loading direction) acted as “hard” grains that have the lowest Schmid factor with the highest Taylor factor and GND density compared with other oriented grains. A high GND content was found in the vicinity of the grain boundaries in the soft grains and on slip plane traces within the hard grains. It is concluded that GND absolute value for each grain can vary, as it is interrelated with deformation degree, but the GND locations within the grains give indications of the strain hardening state and deformation stages in hard and soft grains. Furthermore, the areas with random local texture contained high strain incompatibilities between neighbouring

  15. Design and performance investigation of a highly accurate apodized fiber Bragg grating-based strain sensor in single and quasi-distributed systems. (United States)

    Ali, Taha A; Shehata, Mohamed I; Mohamed, Nazmi A


    In this work, fiber Bragg grating (FBG) strain sensors in single and quasi-distributed systems are investigated, seeking high-accuracy measurement. Since FBG-based strain sensors of small lengths are preferred in medical applications, and that causes the full width at half-maximum (FWHM) to be larger, a new apodization profile is introduced for the first time, to the best of our knowledge, with a remarkable FWHM at small sensor lengths compared to the Gaussian and Nuttall profiles, in addition to a higher mainlobe slope at these lengths. A careful selection of apodization profiles with detailed investigation is performed-using sidelobe analysis and the FWHM, which are primary judgment factors especially in a quasi-distributed configuration. A comparison between the elite selection of apodization profiles (extracted from related literature) and the proposed new profile is carried out covering the reflectivity peak, FWHM, and sidelobe analysis. The optimization process concludes that the proposed new profile with a chosen small length (L) of 10 mm and Δnac of 1.4×10-4 is the optimum choice for single stage and quasi-distributed strain-sensor networks, even better than the Gaussian profile at small sensor lengths. The proposed profile achieves the smallest FWHM of 15 GHz (suitable for UDWDM), and the highest mainlobe slope of 130 dB/nm. For the quasi-distributed scenario, a noteworthy high isolation of 6.953 dB is achieved while applying a high strain value of 1500 μstrain (με) for a five-stage strain-sensing network. Further investigation was undertaken, proving that consistency in choosing the apodization profile in the quasi-distributed network is mandatory. A test was made of the inclusion of a uniform apodized sensor among other apodized sensors with the proposed profile in an FBG strain-sensor network.

  16. Job strain among blue-collar and white-collar employees as a determinant of total mortality: a 28-year population-based follow-up (United States)

    Seitsamo, Jorma; von Bonsdorff, Monika E; Ilmarinen, Juhani; Nygård, Clas-Håkan; Rantanen, Taina


    Objectives To investigate the effect of job demand, job control and job strain on total mortality among white-collar and blue-collar employees working in the public sector. Design 28-year prospective population-based follow-up. Setting Several municipals in Finland. Participants 5731 public sector employees from the Finnish Longitudinal Study on Municipal Employees Study aged 44–58 years at baseline. Outcomes Total mortality from 1981 to 2009 among individuals with complete data on job strain in midlife, categorised according to job demand and job control: high job strain (high job demands and low job control), active job (high job demand and high job control), passive job (low job demand and low job control) and low job strain (low job demand and high job control). Results 1836 persons died during the follow-up. Low job control among men increased (age-adjusted HR 1.26, 95% CI 1.12 to 1.42) and high job demand among women decreased the risk for total mortality HR 0.82 (95% CI 0.71 to 0.95). Adjustment for occupational group, lifestyle and health factors attenuated the association for men. In the analyses stratified by occupational group, high job strain increased the risk of mortality among white-collar men (HR 1.52, 95% CI 1.09 to 2.13) and passive job among blue-collar men (HR 1.28, 95% CI 1.05 to 1.47) compared with men with low job strain. Adjustment for lifestyle and health factors attenuated the risks. Among white-collar women having an active job decreased the risk for mortality (HR 0.78, 95% CI 0.60 to 1.00). Conclusion The impact of job strain on mortality was different according to gender and occupational group among middle-aged public sector employees. PMID:22422919

  17. Composite cavity based fiber optic Fabry–Perot strain sensors demodulated by an unbalanced fiber optic Michelson interferometer with an electrical scanning mirror

    International Nuclear Information System (INIS)

    Zhang, Jianzhong; Yang, Jun; Sun, Weimin; Yuan, Libo; Jin, Wencai; Peng, G D


    A composite cavity based fiber optic Fabry–Perot strain sensor system, interrogated by a white light source and demodulated by an unbalanced fiber optic Michelson interferometer with an electrical scanning mirror, is proposed and demonstrated. Comparing with the traditional extrinsic fiber optic Fabry–Perot strain sensor, the potential multiplexing capability and the dynamic measurement range are improved simultaneously. At the same time, the measurement stability of the electrical scanning mirror system is improved by the self-referenced signal of the sensor structure

  18. Wolbachia strain wPip yields a pattern of cytoplasmic incompatibility enhancing a Wolbachia-based suppression strategy against the disease vector Aedes albopictus

    Directory of Open Access Journals (Sweden)

    Calvitti Maurizio


    Full Text Available Abstract Background Cytoplasmic incompatibility (CI is induced in nature by Wolbachia bacteria, resulting in conditional male sterility. Previous research demonstrated that the two Wolbachia strains (wAlbA and wAlbB that naturally co-infect the disease vector mosquito Aedes albopictus (Asian tiger mosquito can be replaced with the wPip Wolbachia strain from Culex pipiens. Since Wolbachia-based vector control strategies depend upon the strength and consistency of CI, a greater understanding is needed on the CI relationships between wPip, wAlbA and wAlbB Wolbachia in Ae. albopictus. Methods This work consisted of a collaborative series of crosses carried out in Italy and in US to study the CI relationships between the “wPip” infected Ae. albopictus strain (ARwP and the superinfected SR strain. The Ae. albopictus strains used in Italian tests are the wPip infected ARwP strain (ARwPIT, the superinfected SR strain and the aposymbiotic AR strain. To understand the observed pattern of CI, crossing experiments carried out in USA focused on the study of the CI relationships between ARwP (ARwPUS and artificially-generated single infected lines, in specific HTA and HTB, harbouring only wAlbA and wAlbB Wolbachia respectively. Results The paper reports an unusual pattern of CI observed in crossing experiments between ARwP and SR lines. Specifically, ARwP males are able to induce full sterility in wild type females throughout most of their lifetime, while crosses between SR males and ARwP females become partially fertile with male aging. We demonstrated that the observed decrease in CI penetrance with SR male age, is related to the previously described decrease in Wolbachia density, in particular of the wAlbA strain, occurring in aged superinfected males. Conclusions The results here reported support the use of the ARwP Ae. albopictus line as source of “ready-made sterile males”, as an alternative to gamma radiation sterilized males, for autocidal

  19. Inter- and intra-strain variability of tandem repeats in Mycoplasma pneumoniae based on next-generation sequencing data. (United States)

    Zhang, Jing; Song, Xiaohong; Ma, Marella J; Xiao, Li; Kenri, Tsuyoshi; Sun, Hongmei; Ptacek, Travis; Li, Shaoli; Waites, Ken B; Atkinson, T Prescott; Shibayama, Keigo; Dybvig, Kevin; Feng, Yanmei


    To characterize inter- and intra-strain variability of variable-number tandem repeats (VNTRs) in Mycoplasma pneumoniae to determine the optimal multilocus VNTR analysis scheme for improved strain typing. Whole genome assemblies and next-generation sequencing data from diverse M. pneumoniae isolates were used to characterize VNTRs and their variability, and to compare the strain discriminability of new VNTR and existing markers. We identified 13 VNTRs including five reported previously. These VNTRs displayed different levels of inter- and intra-strain copy number variations. All new markers showed similar or higher discriminability compared with existing VNTR markers and the P1 typing system. Our study provides novel insights into VNTR variations and potential new multilocus VNTR analysis schemes for improved genotyping of M. pneumoniae.

  20. Progress of a Cross-Correlation Based Optical Strain Measurement Technique for Detecting Radial Growth on a Rotating Disk (United States)

    Clem, Michelle M.; Abdul-Aziz, Ali; Woike, Mark R.; Fralick, Gustave C.


    The modern turbine engine operates in a harsh environment at high speeds and is repeatedly exposed to combined high mechanical and thermal loads. The cumulative effects of these external forces lead to high stresses and strains on the engine components, such as the rotating turbine disks, which may eventually lead to a catastrophic failure if left undetected. The operating environment makes it difficult to use conventional strain gauges, therefore, non-contact strain measurement techniques is of interest to NASA and the turbine engine community. This presentation describes one such approach; the use of cross correlation analysis to measure strain experienced by the engine turbine disk with the goal of assessing potential faults and damage.

  1. Force Reconstruction from Ejection Tests of Stores from Aircraft Used for Model Predictions and Missing/Bad Gages

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Michael; Cap, Jerome S.; Starr, Michael J.; Urbina, Angel; Brink, Adam Ray


    One of the more severe environments for a store on an aircraft is during the ejection of the store. During this environment it is not possible to instrument all component responses, and it is also likely that some instruments may fail during the environment testing. This work provides a method for developing these responses from failed gages and uninstrumented locations. First, the forces observed by the store during the environment are reconstructed. A simple sampling method is used to reconstruct these forces given various parameters. Then, these forces are applied to a model to generate the component responses. Validation is performed on this methodology.

  2. Direct measurements of wall shear stress by buried wire gages in a shock-wave boundary-layer interaction region (United States)

    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.

  3. Sequence analysis-based characterization and identification of neurovirulence-associated variants of 36 EV71 strains from China. (United States)

    Xu, Jun; Wang, Fang; Zhao, Desheng; Liu, Jiang; Su, Hong; Wang, Baolong


    Enterovirus 71 (EV71) is the main pathogen of hand-foot-mouth disease (HFMD) and causes several neurological complications. As new strains of EV71 are constantly discovered, it is important to understand the genomic characteristics of the viruses and the mechanism of virulence. Herein, we isolated five strains of EV71 from HFMD patients with or without neurovirulence and sequenced their whole genomes. We then performed whole genome sequence analysis of totally 36 EV71 strains. The phylogenetic analysis of the VP1 region revealed all five isolated strains are clustered into C4a of C4 subgenotype. In addition, by comparing the complete genome sequences of 36 strains, 253 variable amino acid positions were found, 14 of which were identified to be associated with neurovirulence (P < 0.05). Moreover, a similar pattern of amino acid variants combination was identified in four strains without neurovirulence, indicating this type of variant pattern might be associated with avirulence. The strains with neurovirulence appeared to be distinguished from those without neurovirulence by the variants in VP1 and P2 regions, implying VP1 and P2 are the important regions associated with neurovirulence. Indeed, 3-D modeling of VP1 and P2 regions of non-neurovirulent and neurovirulent strains revealed that the different variants resulted in different protein structures and amino acid composition of ligand binding site, which might account for their difference in neurovirulence. In summary, our study reveals 14 variable amino acid positions of VP1, P2 and P3 regions are related to the virulence and that mutations in the capsid proteins of EV71 might contribute to neurovirulence. © 2018 Wiley Periodicals, Inc.

  4. Ultra-high density out-of-plane strain sensor 3D architecture based on sub-20 nm PMOS FinFET

    KAUST Repository

    Ghoneim, Mohamed T.; Alfaraj, Nasir; Sevilla, Galo T.; Hussain, Muhammad Mustafa


    Future wearable electronics require not only flexibility but also preservation of the perks associated with today's high-performance, traditional silicon electronics. In this work we demonstrate a state-of-the-art fin-shaped field-effect transistor (FinFET)-based, out-of-plane strain sensor on flexible silicon through transforming the bulk device in a transfer-less process. The device preserves the functionality and high performance associated with its bulk, inflexible state. Furthermore, gate leakage current shows sufficient dependence on the value of the applied out-of-plane strain that enables permits use of the flexible device as a switching device as well as a strain sensor.

  5. Ultra-high density out-of-plane strain sensor 3D architecture based on sub-20 nm PMOS FinFET

    KAUST Repository

    Ghoneim, Mohamed T.


    Future wearable electronics require not only flexibility but also preservation of the perks associated with today\\'s high-performance, traditional silicon electronics. In this work we demonstrate a state-of-the-art fin-shaped field-effect transistor (FinFET)-based, out-of-plane strain sensor on flexible silicon through transforming the bulk device in a transfer-less process. The device preserves the functionality and high performance associated with its bulk, inflexible state. Furthermore, gate leakage current shows sufficient dependence on the value of the applied out-of-plane strain that enables permits use of the flexible device as a switching device as well as a strain sensor.

  6. Development of an embedded thin-film strain-gauge-based SHM network into 3D-woven composite structure for wind turbine blades (United States)

    Zhao, Dongning; Rasool, Shafqat; Forde, Micheal; Weafer, Bryan; Archer, Edward; McIlhagger, Alistair; McLaughlin, James


    Recently, there has been increasing demand in developing low-cost, effective structure health monitoring system to be embedded into 3D-woven composite wind turbine blades to determine structural integrity and presence of defects. With measuring the strain and temperature inside composites at both in-situ blade resin curing and in-service stages, we are developing a novel scheme to embed a resistive-strain-based thin-metal-film sensory into the blade spar-cap that is made of composite laminates to determine structural integrity and presence of defects. Thus, with fiberglass, epoxy, and a thinmetal- film sensing element, a three-part, low-cost, smart composite laminate is developed. Embedded strain sensory inside composite laminate prototype survived after laminate curing process. The internal strain reading from embedded strain sensor under three-point-bending test standard is comparable. It proves that our proposed method will provide another SHM alternative to reduce sensing costs during the renewable green energy generation.

  7. Distribution of sequence-based types of legionella pneumophila serogroup 1 strains isolated from cooling towers, hot springs, and potable water systems in China. (United States)

    Qin, Tian; Zhou, Haijian; Ren, Hongyu; Guan, Hong; Li, Machao; Zhu, Bingqing; Shao, Zhujun


    Legionella pneumophila serogroup 1 causes Legionnaires' disease. Water systems contaminated with Legionella are the implicated sources of Legionnaires' disease. This study analyzed L. pneumophila serogroup 1 strains in China using sequence-based typing. Strains were isolated from cooling towers (n = 96), hot springs (n = 42), and potable water systems (n = 26). Isolates from cooling towers, hot springs, and potable water systems were divided into 25 sequence types (STs; index of discrimination [IOD], 0.711), 19 STs (IOD, 0.934), and 3 STs (IOD, 0.151), respectively. The genetic variation among the potable water isolates was lower than that among cooling tower and hot spring isolates. ST1 was the predominant type, accounting for 49.4% of analyzed strains (n = 81), followed by ST154. With the exception of two strains, all potable water isolates (92.3%) belonged to ST1. In contrast, 53.1% (51/96) and only 14.3% (6/42) of cooling tower and hot spring, respectively, isolates belonged to ST1. There were differences in the distributions of clone groups among the water sources. The comparisons among L. pneumophila strains isolated in China, Japan, and South Korea revealed that similar clones (ST1 complex and ST154 complex) exist in these countries. In conclusion, in China, STs had several unique allelic profiles, and ST1 was the most prevalent sequence type of environmental L. pneumophila serogroup 1 isolates, similar to its prevalence in Japan and South Korea.

  8. Experimental Method of Temperature and Strain Discrimination in Polymer Composite Material by Embedded Fiber-Optic Sensors Based on Femtosecond-Inscribed FBGs

    Directory of Open Access Journals (Sweden)

    Victor V. Shishkin


    Full Text Available Experimental method of temperature and strain discrimination with fiber Bragg gratings (FBGs sensors embedded in carbon fiber-reinforced plastic is proposed. The method is based on two-fiber technique, when two FBGs inscribed in different fibers with different sensitivities to strain and/or temperature are placed close to each other and act as a single sensing element. The nonlinear polynomial approximation of Bragg wavelength shift as a function of temperature and strain is presented for this method. The FBGs were inscribed with femtosecond laser by point-by-point inscription technique through polymer cladding of the fiber. The comparison of linear and nonlinear approximation accuracies for array of embedded sensors is performed. It is shown that the use of nonlinear approximation gives 1.5–2 times better accuracy. The obtained accuracies of temperature and strain measurements are 2.6–3.8°C and 50–83 με in temperature and strain range of 30–120°C and 0–400 με, respectively.

  9. Giant voltage manipulation of MgO-based magnetic tunnel junctions via localized anisotropic strain: A potential pathway to ultra-energy-efficient memory technology (United States)

    Zhao, Zhengyang; Jamali, Mahdi; D'Souza, Noel; Zhang, Delin; Bandyopadhyay, Supriyo; Atulasimha, Jayasimha; Wang, Jian-Ping


    Voltage control of magnetization via strain in piezoelectric/magnetostrictive systems is a promising mechanism to implement energy-efficient straintronic memory devices. Here, we demonstrate giant voltage manipulation of MgO magnetic tunnel junctions (MTJ) on a Pb(Mg1/3Nb2/3)0.7Ti0.3O3 piezoelectric substrate with (001) orientation. It is found that the magnetic easy axis, switching field, and the tunnel magnetoresistance (TMR) of the MTJ can be efficiently controlled by strain from the underlying piezoelectric layer upon the application of a gate voltage. Repeatable voltage controlled MTJ toggling between high/low-resistance states is demonstrated. More importantly, instead of relying on the intrinsic anisotropy of the piezoelectric substrate to generate the required strain, we utilize anisotropic strain produced using a local gating scheme, which is scalable and amenable to practical memory applications. Additionally, the adoption of crystalline MgO-based MTJ on piezoelectric layer lends itself to high TMR in the strain-mediated MRAM devices.

  10. Analysis of GAGE, NY-ESO-1 and SP17 cancer/testis antigen expression in early stage non-small cell lung carcinoma

    International Nuclear Information System (INIS)

    Gjerstorff, Morten F; Pøhl, Mette; Olsen, Karen E; Ditzel, Henrik J


    The unique expression pattern and immunogenic properties of cancer/testis antigens make them ideal targets for immunotherapy of cancer. The MAGE-A3 cancer/testis antigen is frequently expressed in non-small cell lung cancer (NSCLC) and vaccination with MAGE-A3 in patients with MAGE-A3-positive NSCLC has shown promising results. However, little is known about the expression of other cancer/testis antigens in NSCLC. In the present study the expression of cancer/testis antigens GAGE, NY-ESO-1 and SP17 was investigated in patients with completely resected, early stage, primary NSCLC. Tumor biopsies from normal lung tissue and from a large cohort (n = 169) of NSCLC patients were examined for GAGE, NY-ESO-1 and SP17 protein expression by immunohistochemical analysis. The expression of these antigens was further matched to clinical and pathological features using univariate cox regression analysis. GAGE and NY-ESO-1 cancer/testis antigens were not expressed in normal lung tissue, while SP17 was expressed in ciliated lung epithelia. The frequency of GAGE, NY-ESO-1 and SP17 expression in NSCLC tumors were 26.0% (44/169), 11.8% (20/169) and 4.7% (8/169), respectively, and 33.1% (56/169) of the tumors expressed at least one of these antigens. In general, the expression of GAGE, NY-ESO-1 and SP17 was not significantly associated with a specific histotype (adenocarcinoma vs. squamous cell carcinoma), but high-level GAGE expression (>50%) was more frequent in squamous cell carcinoma (p = 0.02). Furthermore, the frequency of GAGE expression was demonstrated to be significantly higher in stage II-IIIa than stage I NSCLC (17.0% vs. 35.8%; p = 0.02). Analysis of the relation between tumor expression of GAGE and NY-ESO-1 and survival endpoints revealed no significant associations. Our study demonstrates that GAGE, NY-ESO-1 and SP17 cancer/testis antigens are candidate targets for immunotherapy of NSCLC and further suggest that multi-antigen vaccines may be beneficial

  11. Genomic Variability of Mycobacterium tuberculosis Strains of the Euro-American Lineage Based on Large Sequence Deletions and 15-Locus MIRU-VNTR Polymorphism (United States)

    Rindi, Laura; Medici, Chiara; Bimbi, Nicola; Buzzigoli, Andrea; Lari, Nicoletta; Garzelli, Carlo


    A sample of 260 Mycobacterium tuberculosis strains assigned to the Euro-American family was studied to identify phylogenetically informative genomic regions of difference (RD). Mutually exclusive deletions of regions RD115, RD122, RD174, RD182, RD183, RD193, RD219, RD726 and RD761 were found in 202 strains; the RDRio deletion was detected exclusively among the RD174-deleted strains. Although certain deletions were found more frequently in certain spoligotype families (i.e., deletion RD115 in T and LAM, RD174 in LAM, RD182 in Haarlem, RD219 in T and RD726 in the “Cameroon” family), the RD-defined sublineages did not specifically match with spoligotype-defined families, thus arguing against the use of spoligotyping for establishing exact phylogenetic relationships between strains. Notably, when tested for katG463/gyrA95 polymorphism, all the RD-defined sublineages belonged to Principal Genotypic Group (PGG) 2, except sublineage RD219 exclusively belonging to PGG3; the 58 Euro-American strains with no deletion were of either PGG2 or 3. A representative sample of 197 isolates was then analyzed by standard 15-locus MIRU-VNTR typing, a suitable approach to independently assess genetic relationships among the strains. Analysis of the MIRU-VNTR typing results by using a minimum spanning tree (MST) and a classical dendrogram showed groupings that were largely concordant with those obtained by RD-based analysis. Isolates of a given RD profile show, in addition to closely related MIRU-VNTR profiles, related spoligotype profiles that can serve as a basis for better spoligotype-based classification. PMID:25197794

  12. Strain Variation along Cimandiri Fault, West Java Based on Continuous and Campaign GPS Observation From 2006-2016 (United States)

    Safitri, A. A.; Meilano, I.; Gunawan, E.; Abidin, H. Z.; Efendi, J.; Kriswati, E.


    The Cimandiri fault which is running in the direction from Pelabuhan Ratu to Padalarang is the longest fault in West Java with several previous shallow earthquakes in the last 20 years. By using continues and campaign GPS observation from 2006-2016, we obtain the deformation pattern along the fault through the variation of strain tensor. We use the velocity vector of GPS station which is fixed in stable International Terrestrial Reference Frame 2008 to calculate horizontal strain tensor. Least Square Collocation is applied to produce widely dense distributed velocity vector and optimum scale factor for the Least Square Weighting matrix. We find that the strain tensor tend to change from dominantly contraction in the west to dominantly extension to the east of fault. Both the maximum shear strain and dilatation show positive value along the fault and increasing from the west to the east. The findings of strain tensor variation along Cimandiri Fault indicate the post seismic effect of the 2006 Java Earthquake.

  13. A packaged, low-cost, robust optical fiber strain sensor based on small cladding fiber sandwiched within periodic polymer grating. (United States)

    Chiang, Chia-Chin; Li, Chein-Hsing


    In the present study, a novel packaged long-period fiber grating (PLPFG) strain sensor is first presented. The MEMS process was utilized to fabricate the packaged optical fiber strain sensor. The sensor structure consisted of etched optical fiber sandwiched between two layers of thick photoresist SU-8 3050 and then packaged with poly (dimethylsiloxane) (PDMS) polymer material to construct the PLPFG strain sensor. The PDMS packaging material was used to prevent the glue effect, wherein glue flows into the LPFG structure and reduces coupling strength, in the surface bonding process. Because the fiber grating was packaged with PDMS material, it was effectively protected and made robust. The resonance attenuation dip of PLPFG grows when it is loading. This study explored the size effect of the grating period and fiber diameter of PLPFG via tensile testing. The experimental results found that the best strain sensitivity of the PLPFG strain sensor was -0.0342 dB/με, and that an R2 value of 0.963 was reached.

  14. Changes in job strain and subsequent weight gain: a longitudinal study, based on the Danish Nurse Cohort. (United States)

    Vesterlund, Gitte Kingo; Keller, Amélie Cléo; Heitmann, Berit Lilienthal


    Obesity as well as job strain is increasing, and job strain might contribute to weight gain. The objective of the current study was to examine associations between longitudinal alterations in the components of job strain and subsequent weight gain. The study was designed as a prospective cohort study with three questionnaire surveys enabling measurement of job-strain alterations over 6 years and subsequent measurements of weight gain after further 10 years of follow-up. ANCOVA and trend analyses were conducted. Job demands were measured as job busyness and speed, and control as amount of influence. Employed nurses in Denmark. We included a sub-sample of 6188 female nurses from the Danish Nurse Cohort, which consisted of the nurses who participated in surveys in 1993, 1999 and 2009. A linear trend in weight gain was seen in nurses who were often busy in 1999 between those who were rarely v. sometimes v. often busy in 1993 (P=0·03), with the largest weight gain in individuals with sustained high busyness in both years. Loss of influence between 1993 and 1999 was associated with larger subsequent weight gain than sustained high influence (P=0·003) or sustained low influence (P=0·02). For speed, no associations were found. Busyness, speed and influence differed in their relationship to subsequent weight gain. A decrease in job influence and a sustained burden of busyness were most strongly related to subsequent weight gain. Focus on job strain reduction and healthy diet is essential for public health.

  15. Type I Diabetic Akita Mouse Model is Characterized by Abnormal Cardiac Deformation During Early Stages of Diabetic Cardiomyopathy with Speckle-Tracking Based Strain Imaging. (United States)

    Zhou, Yingchao; Xiao, Hong; Wu, Jianfei; Zha, Lingfeng; Zhou, Mengchen; Li, Qianqian; Wang, Mengru; Shi, Shumei; Li, Yanze; Lyu, Liangkun; Wang, Qing; Tu, Xin; Lu, Qiulun


    Diabetes mellitus (DM) has been demonstrated to have a strong association with heart failure. Conventional echocardiographic analysis cannot sensitively monitor cardiac dysfunction in type I diabetic Akita hearts, but the phenotype of heart failure is observed in molecular levels during the early stages. Male Akita (Ins2WT/C96Y) mice were monitored with echocardiographic imaging at various ages, and then with conventional echocardiographic analysis and speckle-tracking based strain analyses. With speckle-tracking based strain analyses, diabetic Akita mice showed changes in average global radial strain at the age of 12 weeks, as well as decreased longitudinal strain. These changes occurred in the early stage and remained throughout the progression of diabetic cardiomyopathy in Akita mice. Speckle-tracking showed that the detailed and precise changes of cardiac deformation in the progression of diabetic cardiomyopathy in the genetic type I diabetic Akita mice were uncoupled. We monitored early-stage changes in the heart of diabetic Akita mice. We utilize this technique to elucidate the underlying mechanism for heart failure in Akita genetic type I diabetic mice. It will further advance the assessment of cardiac abnormalities, as well as the discovery of new drug treatments using Akita genetic type I diabetic mice. © 2018 The Author(s). Published by S. Karger AG, Basel.

  16. Application of carbon nanotubes flexible strain sensor in smart textiles

    Directory of Open Access Journals (Sweden)

    Qiong CHENG


    Full Text Available Smart textiles have not only the necessary functions of daily wear, but also the intelligence. The focus of the current textile materials research is the selection of flexible material. For flexible materials, carbon material is one of the ideal materials for preparing flexible strain gauges. The application of flexible strain sensor prepared by carbon nanotubes as a flexible material in smart textiles is the research content. The research status of carbon nanotubes flexible strain sensor is introduced from the aspects of the structure, properties and application. The characteristics and functions of flexible strain gages prepared with carbon nanotube fibers and carbon nanotube films as flexible materials are discussed in terms of selection, preparation method, performance test and application. At the same time, the advantages and disadvantages of the flexible strain sensor of carbon nanotubes are reviewed from the aspects of preparation difficulty, production cost and practical application effect. High sensitivity with high strain will be a key research direction for carbon nanotube flexible strain sensors.

  17. Prolonged job strain and subsequent risk of cancer in women–a longitudinal study, based on the Danish Nurse Cohort

    DEFF Research Database (Denmark)

    Vesterlund, Gitte K.; Høeg, Beverley L.; Johansen, Christoffer


    Background: The role of psychological stress in cancer risk is continuously debated. Stress at work is the most common form of stress and previous studies have shown inconsistent results regarding cancer risk. In this longitudinal study, we examined the association between prolonged job strain......-related, digestive and lung cancers according to level of prolonged job strain. The women were followed from 1 January 2000 until cancer diagnosis, emigration, death or 31 December 2013 (mean follow-up 13 years) and models were adjusted for potential confounders. Effect modification was examined according to working...... nightshifts and full time. Results: No significant differences in the risk of overall cancer or any of the cancer subgroups were identified in relation to prolonged busyness, speed, influence, or overall job strain. Effect modification by working full time was observed when examining job influence in relation...

  18. Self-Evaluation of PANDA-FBG Based Sensing System for Dynamic Distributed Strain and Temperature Measurement. (United States)

    Zhu, Mengshi; Murayama, Hideaki; Wada, Daichi


    A novel method is introduced in this work for effectively evaluating the performance of the PANDA type polarization-maintaining fiber Bragg grating (PANDA-FBG) distributed dynamic strain and temperature sensing system. Conventionally, the errors during the measurement are unknown or evaluated by using other sensors such as strain gauge and thermocouples. This will make the sensing system complicated and decrease the efficiency since more than one kind of sensor is applied for the same measurand. In this study, we used the approximately constant ratio of primary errors in strain and temperature measurement and realized the self-evaluation of the sensing system, which can significantly enhance the applicability, as well as the reliability in strategy making.

  19. Strain Measurement during Stress Rupture of Composite Over-Wrapped Pressure Vessel with Fiber Bragg Gratings Sensors (United States)

    Banks, Curtis E.; Grant, Joseph; Russell, Sam; Arnett, Shawn


    Fiber optic Bragg gratings were used to measure strain fields during Stress Rupture (SSM) test of Kevlar Composite Over-Wrapped Pressure Vessels (COPV). The sensors were embedded under the over-wrapped attached to the liner released from the Kevlar and attached to the Kevlar released from the liner. Additional sensors (foil gages and fiber bragg gratings) were surface mounted on the COPY liner.

  20. Low-flow analysis and selected flow statistics representative of 1930-2002 for streamflow-gaging stations in or near West Virginia (United States)

    Wiley, Jeffrey B.


    Five time periods between 1930 and 2002 are identified as having distinct patterns of annual minimum daily mean flows (minimum flows). Average minimum flows increased around 1970 at many streamflow-gaging stations in West Virginia. Before 1930, however, there might have been a period of minimum flows greater than any period identified between 1930 and 2002. The effects of climate variability are probably the principal causes of the differences among the five time periods. Comparisons of selected streamflow statistics are made between values computed for the five identified time periods and values computed for the 1930-2002 interval for 15 streamflow-gaging stations. The average difference between statistics computed for the five time periods and the 1930-2002 interval decreases with increasing magnitude of the low-flow statistic. The greatest individual-station absolute difference was 582.5 percent greater for the 7-day 10-year low flow computed for 1970-1979 compared to the value computed for 1930-2002. The hydrologically based low flows indicate approximately equal or smaller absolute differences than biologically based low flows. The average 1-day 3-year biologically based low flow (1B3) and 4-day 3-year biologically based low flow (4B3) are less than the average 1-day 10-year hydrologically based low flow (1Q10) and 7-day 10-year hydrologic-based low flow (7Q10) respectively, and range between 28.5 percent less and 13.6 percent greater. Seasonally, the average difference between low-flow statistics computed for the five time periods and 1930-2002 is not consistent between magnitudes of low-flow statistics, and the greatest difference is for the summer (July 1-September 30) and fall (October 1-December 31) for the same time period as the greatest difference determined in the annual analysis. The greatest average difference between 1B3 and 4B3 compared to 1Q10 and 7Q10, respectively, is in the spring (April 1-June 30), ranging between 11.6 and 102.3 percent

  1. Report on an Assessment of the Application of EPP Results from the Strain Limit Evaluation Procedure to the Prediction of Cyclic Life Based on the SMT Methodology

    Energy Technology Data Exchange (ETDEWEB)

    Jetter, R. I. [R. I. Jetter Consulting, Pebble Beach, CA (United States); Messner, M. C. [Argonne National Lab. (ANL), Argonne, IL (United States); Sham, T. -L. [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, Y. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)


    The goal of the proposed integrated Elastic Perfectly-Plastic (EPP) and Simplified Model Test (SMT) methodology is to incorporate an SMT data based approach for creep-fatigue damage evaluation into the EPP methodology to avoid the separate evaluation of creep and fatigue damage and eliminate the requirement for stress classification in current methods; thus greatly simplifying evaluation of elevated temperature cyclic service. This methodology should minimize over-conservatism while properly accounting for localized defects and stress risers. To support the implementation of the proposed methodology and to verify the applicability of the code rules, analytical studies and evaluation of thermomechanical test results continued in FY17. This report presents the results of those studies. An EPP strain limits methodology assessment was based on recent two-bar thermal ratcheting test results on 316H stainless steel in the temperature range of 405 to 7050C. Strain range predictions from the EPP evaluation of the two-bar tests were also evaluated and compared with the experimental results. The role of sustained primary loading on cyclic life was assessed using the results of pressurized SMT data from tests on Alloy 617 at 9500C. A viscoplastic material model was used in an analytic simulation of two-bar tests to compare with EPP strain limits assessments using isochronous stress strain curves that are consistent with the viscoplastic material model. A finite element model of a prior 304H stainless steel Oak Ridge National Laboratory (ORNL) nozzle-to-sphere test was developed and used for an EPP strain limits and creep-fatigue code case damage evaluations. A theoretical treatment of a recurring issue with convergence criteria for plastic shakedown illustrated the role of computer machine precision in EPP calculations.

  2. Application of indirect stress measurement techniques (non strain gauge based technology) to quantify stress environments in mines

    CSIR Research Space (South Africa)

    Stacey, TR


    Full Text Available Reliable values of in situ stress are essential for the valid modelling of mine layouts. Available non-strain gauge methods are reviewed as potential practical techniques for South African mines. From this review it is concluded that the most...

  3. Characterizing Strain Variation in Engineered E. coli Using a Multi-Omics-Based Workflow

    DEFF Research Database (Denmark)

    Brunk, Elizabeth; George, Kevin W.; Alonso-Gutierrez, Jorge


    . Application of this workflow identified the roles of candidate genes, pathways, and biochemical reactions in observed experimental phenomena and facilitated the construction of a mutant strain with improved productivity. The contributed workflow is available as an open-source tool in the form of iPython...

  4. Covalent surface modification of prions: a mass spectrometry-based means of detecting distinctive structural features of prion strains (United States)

    Prions (PrPSc) are molecular pathogens that are able to convert the isosequential normal cellular prion protein (PrPC) into a prion. The only demonstrated differences between PrPC and PrPSc is conformational, they are isoforms. A given host can be infected by more than one kind or strain of prion. F...

  5. Influence of Cement Particle-Size Distribution on Early Age Autogenous Strains and Stresses in Cement-Based Materials

    DEFF Research Database (Denmark)

    Bentz, Dale P.; Jensen, Ole Mejlhede; Hansen, Kurt Kielsgaard


    The influence of cement particle-size distribution on autogenous strains and stresses in cement pastes of identical water-to-cement ratios is examined for cement powders of four different finenesses. Experimental measurements include chemical shrinkage, to quantify degree of hydration; internal r...

  6. Fiber Bragg grating based spatially resolved characterization of flux-pinning induced strain of rectangular-shaped bulk YBCO samples

    International Nuclear Information System (INIS)

    Latka, Ines; Habisreuther, Tobias; Litzkendorf, Doris


    Highlights: → Fiber Bragg gratings (FBG) act as strain sensors, also at cryogenic temperatures. → FBGs are not sensitive to magnetic fields. → Local, shape dependent magnetostriction was detected on rectangular samples. → Magnetostrictive effects of the top surface and in a gap between two samples are different. - Abstract: We report on measurements of the spatially resolved characterization of flux-pinning induced strain of rectangular-shaped bulk YBCO samples. The spatially resolved strain measurements are accomplished by the use 2 fiber Bragg grating arrays, which are with an included angle of 45 o fixed to the surface. In this paper first attempts to confirm the shape distortions caused by the flux-pinning induced strain as predicted in will be presented. Two sample setups, a single bulk and a 'mirror' arrangement, will be compared. This mirror setup represents a model configuration for a measurement inside the superconductor, where demagnetization effects can be neglected and the magnetic field merely has a z-component.

  7. An autonomous strain-based Structural Monitoring Framework for Life-Cycle Analysis of a Novel Structure

    Directory of Open Access Journals (Sweden)

    Yunus Emre Harmanci


    Full Text Available In recent years, developed societies have largely adopted smart systems operating on the basis of information extracted from data. For infrastructure systems as well, Structural Health Monitoring (SHM has long advocated a data-driven scheme for facilitating the operation and maintenance of infrastructure. In materializing such a goal, this paper demonstrates the procedures and outcomes of a SHM framework employed on an unconventional structure, namely the recently built Kaeng Krachan Elephant Shelter at the Zurich Zoo, relying on a deployed set of Fiber Bragg Grating (FBG strain sensors. The structure comprises an 80 meter span free-form timber-composite cupola, carried by a post-tensioned reinforced concrete (RC ring. FBG strain sensors are embedded into the ring in close vicinity to critical regions, selected in collaboration with the design engineers. The continuously acquired strain data is then exploited for extraction of performance indicators, relying on implementation of output-only identification methodologies. To this end, a non-parametric and a parametric output-only method, namely a Principal Component Analysis (PCA scheme versus a Vector AutoRegressive (VAR model, are employed and compared. Pre-conditioning of the predictive model is performed on the healthy, or undamaged, state of the structure, and the misfit between model predictions and subsequent measurements is exploited as a damage precursor. The VAR scheme proves in this case a more robust representation of the measured strains, when compared against PCA, as a result of its inherent feature of memory.

  8. Exploiting strain to enhance the Bi incorporation in GaAs-based III/V semiconductors using MOVPE (United States)

    Nattermann, L.; Ludewig, P.; Sterzer, E.; Volz, K.


    Bi containing III/V semiconductors are frequently mentioned for their importance as part of the next generation of optoelectronic devices. Bi containing ternary and quaternary materials like Ga(AsBi), Ga(NAsBi) or Ga(PAsBi) are promising candidates to meet the requirements for new laser structures for telecommunications and solar cell applications. However, in previous studies it was determined that the incorporation of sufficient amounts of Bi still poses a challenge, especially when using MOVPE (metalorganic vapour phase epitaxy) as the growth technique. In order to figure out which mechanisms are responsible for the limitation of Bi incorporation, this work deals with the question of whether there is a relationship between strain, induced by the large Bi atoms, and the saturation level of Bi incorporation in Ga(AsBi). Ga(NAsBi) structures were grown by MOVPE at a low temperature, 400 °C, and compared to Ga(PAsBi) as well as Ga(AsBi) growth. By using the two group V atoms P and N, which have a smaller covalent radius than Bi, the effect of local strain compensation was investigated systematically. The comparison of Bi incorporation in the two quaternary materials systems proved the importance of local strain for the limitation of Bi incorporation, in addition to other effects, like Bi surface coverage and hydrocarbon groups at the growth surface. This, of course, also opens up ways to strain-state-engineer the Bi incorporation in semiconductor alloys.

  9. Assessing the small-strain soil stiffness for offshore wind turbines based on in situ seismic measurements

    NARCIS (Netherlands)

    Versteijlen, W.G.; Van Dalen, K.N.; Metrikine, A.; Hamre, L.


    In this contribution, in situ seismic measurements are used to derive the small-strain shear modulus of soil as input for two soil-structure interaction (SSI) models to assess the initial soil stiffness for offshore wind turbine foundations. This stiffness has a defining influence on the first

  10. Flexible piezotronic strain sensor. (United States)

    Zhou, Jun; Gu, Yudong; Fei, Peng; Mai, Wenjie; Gao, Yifan; Yang, Rusen; Bao, Gang; Wang, Zhong Lin


    Strain sensors based on individual ZnO piezoelectric fine-wires (PFWs; nanowires, microwires) have been fabricated by a simple, reliable, and cost-effective technique. The electromechanical sensor device consists of a single electrically connected PFW that is placed on the outer surface of a flexible polystyrene (PS) substrate and bonded at its two ends. The entire device is fully packaged by a polydimethylsiloxane (PDMS) thin layer. The PFW has Schottky contacts at its two ends but with distinctly different barrier heights. The I- V characteristic is highly sensitive to strain mainly due to the change in Schottky barrier height (SBH), which scales linear with strain. The change in SBH is suggested owing to the strain induced band structure change and piezoelectric effect. The experimental data can be well-described by the thermionic emission-diffusion model. A gauge factor of as high as 1250 has been demonstrated, which is 25% higher than the best gauge factor demonstrated for carbon nanotubes. The strain sensor developed here has applications in strain and stress measurements in cell biology, biomedical sciences, MEMS devices, structure monitoring, and more.

  11. Strain-Annealing Based Grain Boundary Engineering to Evaluate its Sole Implication on Intergranular Corrosion in Extra-Low Carbon Type 304L Austenitic Stainless Steel (United States)

    Pradhan, S. K.; Bhuyan, P.; Kaithwas, C.; Mandal, Sumantra


    Strain-annealing based thermo-mechanical processing has been performed to promote grain boundary engineering (GBE) in an extra-low carbon type austenitic stainless steel without altering the grain size and residual strain to evaluate its sole influence on intergranular corrosion. Single-step processing comprising low pre-strain ( 5 and 10 pct) followed by annealing at 1273 K for 1 hour have resulted in a large fraction of Σ3 n boundaries and significant disruption in random high-angle grain boundaries (RHAGBs) connectivity. This is due to the occurrence of prolific multiple twinning in these specimens as confirmed by their large twin-related domain and twin-related grain size ratio. Among the iterative processing, the schedule comprising two cycles of 10 and 5 pct deformation followed by annealing at 1173 K for 1 hour has yielded the optimum GBE microstructure with the grain size and residual strain akin to the as-received condition. The specimens subjected to the higher number of iterations failed to realize GBE microstructures due to the occurrence of partial recrystallization. Owing to the optimum grain boundary character distribution, the GBE specimen has exhibited remarkable resistance against sensitization and intergranular corrosion as compared to the as-received condition. Furthermore, the lower depth of percolation in the GBE specimen is due to the significant disruption of RHAGBs connectivity as confirmed from its large twin-related domain and lower fractal dimension.

  12. A High-Resolution Demodulation Algorithm for FBG-FP Static-Strain Sensors Based on the Hilbert Transform and Cross Third-Order Cumulant

    Directory of Open Access Journals (Sweden)

    Wenzhu Huang


    Full Text Available Static strain can be detected by measuring a cross-correlation of reflection spectra from two fiber Bragg gratings (FBGs. However, the static-strain measurement resolution is limited by the dominant Gaussian noise source when using this traditional method. This paper presents a novel static-strain demodulation algorithm for FBG-based Fabry-Perot interferometers (FBG-FPs. The Hilbert transform is proposed for changing the Gaussian distribution of the two FBG-FPs’ reflection spectra, and a cross third-order cumulant is used to use the results of the Hilbert transform and get a group of noise-vanished signals which can be used to accurately calculate the wavelength difference of the two FBG-FPs. The benefit by these processes is that Gaussian noise in the spectra can be suppressed completely in theory and a higher resolution can be reached. In order to verify the precision and flexibility of this algorithm, a detailed theory model and a simulation analysis are given, and an experiment is implemented. As a result, a static-strain resolution of 0.9 nε under laboratory environment condition is achieved, showing a higher resolution than the traditional cross-correlation method.

  13. Flexible Strain Sensor Based on Layer-by-Layer Self-Assembled Graphene/Polymer Nanocomposite Membrane and Its Sensing Properties (United States)

    Zhang, Dongzhi; Jiang, Chuanxing; Tong, Jun; Zong, Xiaoqi; Hu, Wei


    Graphene is a potential building block for next generation electronic devices including field-effect transistors, chemical sensors, and radio frequency switches. Investigations of strain application of graphene-based films have emerged in recent years, but the challenges in synthesis and processing achieving control over its fabrication constitute the main obstacles towards device applications. This work presents an alternative approach, layer-by-layer self-assembly, allowing a controllable fabrication of graphene/polymer film strain sensor on flexible substrates of polyimide with interdigital electrodes. Carboxylated graphene and poly (diallyldimethylammonium chloride) (PDDA) were exploited to form hierarchical nanostructure due to electrostatic action. The morphology and structure of the film were inspected by using scanning electron microscopy, x-ray diffraction and Fourier transform infrared spectroscopy. The strain-sensing properties of the graphene/PDDA film sensor were investigated through tuning micrometer caliper exertion and a PC-assisted piezoresistive measurement system. Experimental result shows that the sensor exhibited not only excellent response and reversibility behavior as a function of deflection, but also good repeatability and acceptable linearity. The strain-sensing mechanism of the proposed sensor was attributed to the electrical resistance change resulted from piezoresistive effect.

  14. Effects of activity-rest schedules on physiological strain and spinal load in hospital-based porters. (United States)

    Beynon, C; Burke, J; Doran, D; Nevill, A


    Workers in physically demanding occupations require rest breaks to recover from physiological stress and biomechanical loading. Physiological stress can increase the risk of developing musculoskeletal disorders and repeated loading of the spine may increase the potential for incurring back pain. The aim of the study was to assess the impact of an altered activity-rest schedule on physiological and spinal loading in hospital-based porters. An existing 4-h activity-rest schedule was obtained from observations on eight male porters. This schedule formed the normal trial, which included two 5- and one 15-min breaks. An alternative 4-h schedule was proposed (experimental condition) that had two breaks each of 12.5 min. It was hypothesized that the experimental trial is more effective in promoting recovery from physiological strain and spinal shrinkage than the normal trial, due to the 5-min breaks being insufficient to allow physiological variables to return to resting levels or the intervertebral discs to reabsorb fluid. Ten males performed both test conditions and oxygen uptake VO2, heart rate, minute ventilation VE, perceived exertion and spinal shrinkage were recorded. There were no significant differences in any of the measured variables between the two trials (p > 0.05). Median heart rates were 78 (range 71-93) and 82 (71-90) beats.min(-1) for the normal trial and the experimental trial respectively, indicating that the activity was of low intensity. The light intensity was corroborated by the oxygen uptakes (0.75, range 0.65-0.94 1.min(-1)). Spinal shrinkage occurred to the same extent in the two trials (2.12 +/- 3.16 mm and 2.88 +/- 2.92 mm in the normal trial and the experimental trial respectively). Varying the length and positioning of the rest breaks did not significantly affect the physiological responses or magnitude of spinal shrinkage between the two trials. More physically demanding work than the porters' schedule should induce greater physiological

  15. Nursing staff competence, work strain, stress and satisfaction in elderly care: a comparison of home-based care and nursing homes. (United States)

    Hasson, Henna; Arnetz, Judith E


    The aims of this study were to: (1) compare older people care nursing staff's perceptions of their competence, work strain and work satisfaction in nursing homes and home-based care; and (2) to examine determinants of work satisfaction in both care settings. The shift in older people care from hospitals to community-based facilities and home care has had implications for nursing practice. Lack of competence development, high levels of work strain and low levels of work satisfaction among nursing staff in both care settings have been associated with high turnover. Few studies have compared staff perceptions of their competence and work in nursing homes as opposed to home-based care. A cross-sectional questionnaire survey. Nursing staff perceptions of their competence, work strain, stress and satisfaction were measured by questionnaire in 2003 in two older people care organizations in Sweden. Comparisons of all outcome variables were made between care settings both within and between the two organizations. Multiple regression analysis was used to determine predictors of work satisfaction in home care and nursing homes respectively. In general, staff in home-based care reported significantly less sufficient knowledge compared with staff in nursing homes. However, home care staff experienced significantly less physical and emotional strain compared with staff in nursing homes. Ratings of work-related exhaustion, mental energy and overall work satisfaction did not differ significantly between care settings. In both care settings, work-related exhaustion was the strongest (inverse) predictor of work satisfaction. Future interventions should focus on counteracting work-related exhaustion and improving competence development to improve work satisfaction among older people care nursing staff in both care settings. Relevance to clinical practice. Work-related exhaustion and lack of competence development may have significant negative implications for work satisfaction among

  16. Impact of Cardiac Resynchronization Therapy on Left Ventricular Mechanics: Understanding the Response through a New Quantitative Approach Based on Longitudinal Strain Integrals. (United States)

    Bernard, Anne; Donal, Erwan; Leclercq, Christophe; Schnell, Frédéric; Fournet, Maxime; Reynaud, Amélie; Thebault, Christophe; Mabo, Philippe; Daubert, J-Claude; Hernandez, Alfredo


    The mechanisms of improvement of left ventricular (LV) function with cardiac resynchronization therapy (CRT) are not yet elucidated. The aim of this study was to describe a new tool based on automatic quantification of the integrals of regional longitudinal strain signals and evaluate changes in LV strain distribution after CRT. This was a retrospective observational study of 130 patients with heart failure before CRT device implantation and after 3 to 6 months of follow-up. Integrals of regional longitudinal strain signals (from the beginning of the cardiac cycle to strain peak [IL,peak] and to the instant of aortic valve closure [IL,avc]) were analyzed retrospectively with custom-made algorithms. Response to CRT was defined as a decrease in LV end-systolic volume of ≥15%. Responders (61%) and nonresponders (39%) showed similar baseline values of regional IL,peak and IL,avc. At follow-up, significant improvements of midlateral IL,peak and of midlateral IL,avc were noted only in responders. Midlateral IL,avc showed a relative increase of 151 ± 276% in responders, whereas a decrease of 33 ± 69% was observed in nonresponders. The difference between IL,avc and IL,peak (representing wasted energy of the LV myocardium) of the lateral wall showed a relative change of -59 ± 103% in responders between baseline and CRT, whereas in nonresponders, the relative change was 21 ± 113% (P = .009). Strain integrals revealed changes between baseline and CRT in the lateral wall, demonstrating the beneficial effects of CRT on LV mechanics with favorable myocardial reverse remodeling. Copyright © 2015 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

  17. Genomic diversity of Mycobacterium tuberculosis Beijing strains isolated in Tuscany, Italy, based on large sequence deletions, SNPs in putative DNA repair genes and MIRU-VNTR polymorphisms. (United States)

    Garzelli, Carlo; Lari, Nicoletta; Rindi, Laura


    The Beijing genotype of Mycobacterium tuberculosis is cause of global concern as it is rapidly spreading worldwide, is considered hypervirulent, and is most often associated to massive spread of MDR/XDR TB, although these epidemiological or pathological properties have not been confirmed for all strains and in all geographic settings. In this paper, to gain new insights into the biogeographical heterogeneity of the Beijing family, we investigated a global sample of Beijing strains (22% from Italian-born, 78% from foreign-born patients) by determining large sequence polymorphism of regions RD105, RD181, RD150 and RD142, single nucleotide polymorphism of putative DNA repair genes mutT4 and mutT2 and MIRU-VNTR profiles based on 11 discriminative loci. We found that, although our sample of Beijing strains showed a considerable genomic heterogeneity, yielding both ancient and recent phylogenetic strains, the prevalent successful Beijing subsets were characterized by deletions of RD105 and RD181 and by one nucleotide substitution in one or both mutT genes. MIRU-VNTR analysis revealed 47 unique patterns and 9 clusters including a total of 33 isolates (41% of total isolates); the relatively high proportion of Italian-born Beijing TB patients, often occurring in mixed clusters, supports the possibility of an ongoing cross-transmission of the Beijing genotype to autochthonous population. High rates of extra-pulmonary localization and drug-resistance, particularly MDR, frequently reported for Beijing strains in other settings, were not observed in our survey. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. CE-MS-based metabolomics reveals the metabolic profile of maitake mushroom (Grifola frondosa) strains with different cultivation characteristics. (United States)

    Sato, Mayumi; Miyagi, Atsuko; Yoneyama, Shozo; Gisusi, Seiki; Tokuji, Yoshihiko; Kawai-Yamada, Maki


    Maitake mushroom (Grifola frondosa [Dicks.] Gray) is generally cultured using the sawdust of broadleaf trees. The maitake strain Gf433 has high production efficiency, with high-quality of fruiting bodies even when 30% of the birch sawdust on the basal substrate is replaced with conifer sawdust. We performed metabolome analysis to investigate the effect of different cultivation components on the metabolism of Gf433 and Mori52 by performing CE-MS on their fruiting bodies in different cultivation conditions to quantify the levels of amino acids, organic acids, and phosphorylated organic acids. We found that amino acid and organic acid content in Gf433 were not affected by the kind of sawdust. However, Gf433 contained more organic acids and less amino acids than Mori52, and Gf433 also contained more chitin compared with Mori52. We believe that these differences in the metabolome contents of the two strains are related to the high production efficiency of Gf433.

  19. Computer simulation of strain-induced ordering in interstitial solutions based on the b.c.c. Ta lattice

    International Nuclear Information System (INIS)

    Blanter, M.S.; Khachaturyan, A.G.


    A computer simulation is made of strain-induced ordering of interstitial atoms within octahedral interstices in the Ta host lattice. The calculation technique allows to take into account infinite-range strain-induced interaction. Computer simulation of ordering process enables to model the sequence of structure changes which occur during the ordering process and to find the equilibrium structure of the stable interstitial superstructures. The structures of high-temperature ordering phases obtained by the method of static concentration waves coincide with those obtained by means of computer simulation. However computer simulation enables to predict the structures of low-temperature ordered phases which cannot be obtained by the method of concentration waves. Comparison of computer simulation results and structures of observed ordered phases demonstrates good agreement. (author)

  20. Metallic-packaging fiber Bragg grating sensor based on ultrasonic welding for strain-insensitive temperature measurement (United States)

    Zhu, Lianqing; Yang, Runtao; Zhang, Yumin; Dong, Mingli; Lou, Xiaoping


    In this paper, a metallic-packaging fiber Bragg grating temperature sensor characterized by a strain insensitive design is demonstrated. The sensor is fabricated by the one-step ultrasonic welding technique using type-II fiber Bragg grating combined with an aluminum alloy substrate. Finite element analysis is used to perform theoretical evaluation. The result of the experiment illustrates that the metallic-packaging temperature sensor is insensitive to longitudinal strain. The sensor's temperature sensitivity is 36 pm/°C over the range of 50-110 °C, with the correlation coefficient (R2) being 0.999. The sensor's temporal response is 40 s at a sudden temperature change from 21 °C to 100 °C. The proposed sensor can be applied on reliable and precise temperature measurement.