Relevant bibliographies by topics / Bulk field measurement

Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers

Academic literature on the topic 'Bulk field measurement'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Bulk field measurement"

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Tomita, Masaru, Yusuke Fukumoto, Kenji Suzuki, and Yukikazu Iwasa. "Measurement of the magnetic field of resin-impregnated bulk superconductor annuli." Physica C: Superconductivity and its Applications 470 (December 2010): S33—S34. http://dx.doi.org/10.1016/j.physc.2010.01.020.

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Shibata, M., R. Kinjo, Y. W. Choi, M. Omer, H. Negm, T. Konstantin, K. Yoshida, et al. "Development of a field measurement system for the Bulk HTSC SAU." Journal of Physics: Conference Series 425, no. 3 (March 22, 2013): 032021. http://dx.doi.org/10.1088/1742-6596/425/3/032021.

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Baxter, E. F. "Field measurement of high temperature bulk reaction rates I: Theory and technique." American Journal of Science 302, no. 5 (May 1, 2002): 442–64. http://dx.doi.org/10.2475/ajs.302.5.442.

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GRMELA, L., R. MACKU, and P. TOMANEK. "Near-field measurement of ZnS:Mn nanocrystal and bulk thin-film electroluminescent devices." Journal of Microscopy 229, no. 2 (February 2008): 275–80. http://dx.doi.org/10.1111/j.1365-2818.2008.01900.x.

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Czarnetzki, U., D. Luggenhölscher, V. A. Kadetov, and H. F. Döbele. "Plasma diagnostics by laser spectroscopic electric field measurement." Pure and Applied Chemistry 77, no. 2 (January 1, 2005): 345–58. http://dx.doi.org/10.1351/pac200577020345.

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Laser spectroscopic electric field measurements have the potential to become a versatile tool for the diagnostics of low-temperature plasmas. From the spatially and temporally resolved field distribution in the sheath close to electrodes or surfaces in general, a broad range of important plasma parameters can be inferred directly: electron temperature; ion density distribution; displacement-, ion-, electron-diffusion current density; and the sheath potential. Indirectly, the electron and ion energy distribution functions and information on the ion dynamics in the sheath can also be obtained. Finally, measurements in the quasi-neutral bulk can also reveal even the plasma density distribution with high spatial and temporal resolution. The basic concepts for analysis of the field data are introduced and demonstrated by examples in hydrogen discharges.
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KACHANOSKI, R. G., I. J. VAN WESENBEECK, and E. De JONG. "FIELD SCALE PATTERNS OF SOIL WATER STORAGE FROM NON-CONTACTING MEASUREMENTS OF BULK ELECTRICAL CONDUCTIVITY." Canadian Journal of Soil Science 70, no. 3 (August 1, 1990): 537–42. http://dx.doi.org/10.4141/cjss90-056.

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Soil water storage (0–1.7 m) was measured every 10 m in a 660-m-long transect using a neutron probe and compared to bulk electrical conductivity, ECA, measurements obtained using noncontacting electomagnetic induction meters. Coherency analysis indicated a lack of correlation at scales less than 40 m. At scales greater than 40 m, ECA explained more than 80% of the variation of soil water storage. Measurement of ECA should be a simple and fast method of determining general field patterns of soil water storage. Key words: Spatial variability, soil water, coherency, electromagnetic induction
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Tokuyama, M., Y. Yanagi, and H. Ikuta. "Local measurement of the pulsed field magnetization process of melt-processed bulk superconductor." Physica C: Superconductivity and its Applications 463-465 (October 2007): 405–9. http://dx.doi.org/10.1016/j.physc.2007.03.444.

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Ting Liu, 刘婷, 陈险峰 Xianfeng Chen, 狄子昀 Ziyun Di, 张军锋 Junfeng Zhang, 李新碗 Xinwan Li, and 陈建平 Jianping Chen. "Measurement of the magnetic field-dependent refractive index of magnetic fluids in bulk." Chinese Optics Letters 6, no. 3 (2008): 195–97. http://dx.doi.org/10.3788/col20080603.0195.

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Pop, V. "The Influence of Heat Treatment on Electric Properties of Bulk (Bi,Pb):2223 Superconductor." International Journal of Modern Physics B 17, no. 21 (August 20, 2003): 3807–11. http://dx.doi.org/10.1142/s0217979203021824.

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The (Bi,Pb)(Sr,Ba) :2223 samples were prepared using different sintering temperatures. The electrical properties were investigated by electrical resistance and V–I characteristics measurements. The increase of sintering temperature induces the decrease of transition width and the increase of intergranular critical current density Jcj and phase purity. The critical current density from electrical measurement agrees with the results obtained from complex magnetic susceptibility measurements function of temperature and AC field amplitude.
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Nicolaou, Georgios, Robert Wicks, George Livadiotis, Daniel Verscharen, Christopher Owen, and Dhiren Kataria. "Determining the Bulk Parameters of Plasma Electrons from Pitch-Angle Distribution Measurements." Entropy 22, no. 1 (January 16, 2020): 103. http://dx.doi.org/10.3390/e22010103.

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Electrostatic analysers measure the flux of plasma particles in velocity space and determine their velocity distribution function. There are occasions when science objectives require high time-resolution measurements, and the instrument operates in short measurement cycles, sampling only a portion of the velocity distribution function. One such high-resolution measurement strategy consists of sampling the two-dimensional pitch-angle distributions of the plasma particles, which describes the velocities of the particles with respect to the local magnetic field direction. Here, we investigate the accuracy of plasma bulk parameters from such high-resolution measurements. We simulate electron observations from the Solar Wind Analyser’s (SWA) Electron Analyser System (EAS) on board Solar Orbiter. We show that fitting analysis of the synthetic datasets determines the plasma temperature and kappa index of the distribution within 10% of their actual values, even at large heliocentric distances where the expected solar wind flux is very low. Interestingly, we show that although measurement points with zero counts are not statistically significant, they provide information about the particle distribution function which becomes important when the particle flux is low. We also examine the convergence of the fitting algorithm for expected plasma conditions and discuss the sources of statistical and systematic uncertainties.
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Dissertations / Theses on the topic "Bulk field measurement"

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Armistead, K. "A series approach to wetting and layering transitions." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379879.

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Park, Keunhan. "Thermal Characterization of Heated Microcantilevers and a Study on Near-Field Radiation." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14597.

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Recently, remarkable advances have been made in the understanding of micro/nanoscale energy transport, opening new opportunities in various areas such as thermal management, data storage, and energy conversion. This dissertation focuses on thermally-sensed nanotopography using a heated silicon microcantilever and near-field thermophotovoltaic (TPV) energy conversion system. A heated microcantilever is a functionalized atomic force microscope (AFM) cantilever that has a small resistive heater integrated at the free end. Besides its capability of increasing the heater temperature over 1,000 K, the resistance of a heated cantilever is a very sensitive function of temperature, suggesting that the heated cantilever can be used as a highly sensitive thermal metrology tool. The first part of the dissertation discusses the thermal characterization of the heated microcantilever for its usage as a thermal sensor in various conditions. Particularly, the use of heated cantilevers for tapping-mode topography imaging will be presented, along with the recent experimental results on the thermal interaction between the cantilever and substrate. In the second part of the dissertation, the so-called near-field TPV device is introduced. This new type of energy conversion system utilizes the significant enhancement of radiative energy transport due to photon tunneling and surface polaritons. Investigation of surface and bulk polaritons in a multilayered structure reveals that radiative properties are significantly affected by polariton excitations. The dissertation then addresses the rigorous performance analysis of the near-field TPV system and a novel design of a near-field TPV device.
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Books on the topic "Bulk field measurement"

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Influence of bulk turbulence and entrance boundary layer thickness on the curved duct flow field. [Washington, DC]: National Aeronautics and Space Administration, Scientific and Technical Information Division, 1988.

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Furst, Eric M., and Todd M. Squires. Light scattering microrheology. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199655205.003.0005.

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The fundamentals and best practices of passive microrheology using dynamic light scattering and diffusing wave spectroscopy are discussed. The principles of light scattering are introduced and applied in both the single and multiple scattering regimes, including derivations of the light and field autocorrelation functions. Applications to high-frequency microrheology and polymer dynamics are presented, including inertial corrections. Methods to treat gels and other non-ergodic samples, including multi-speckle and optical mixing designs are discussed. Dynamic light scattering (DLS) is a well established method for measuring the motion of colloids, proteins and macromolecules. Light scattering has several advantages for microrheology, especially given the availability of commercial instruments, the relatively large sample volumes that average over many probes, and the sensitivity of the measurement to small particle displacements, which can extend the range of length and timescales probed beyond those typically accessed by the methods of multiple particle tracking and bulk rheology.
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Eriksson, Olle, Anders Bergman, Lars Bergqvist, and Johan Hellsvik. Atomistic Spin Dynamics. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198788669.001.0001.

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The purpose of this book is to provide a theoretical foundation and an understanding of atomistic spin-dynamics, and to give examples of where the atomistic Landau-Lifshitz-Gilbert equation can and should be used. The contents involve a description of density functional theory both from a fundamental viewpoint as well as a practical one, with several examples of how this theory can be used for the evaluation of ground state properties like spin and orbital moments, magnetic form-factors, magnetic anisotropy, Heisenberg exchange parameters, and the Gilbert damping parameter. This book also outlines how interatomic exchange interactions are relevant for the effective field used in the temporal evolution of atomistic spins. The equation of motion for atomistic spin-dynamics is derived starting from the quantum mechanical equation of motion of the spin-operator. It is shown that this lead to the atomistic Landau-Lifshitz-Gilbert equation, provided a Born-Oppenheimer-like approximation is made, where the motion of atomic spins is considered slower than that of the electrons. It is also described how finite temperature effects may enter the theory of atomistic spin-dynamics, via Langevin dynamics. Details of the practical implementation of the resulting stochastic differential equation are provided, and several examples illustrating the accuracy and importance of this method are given. Examples are given of how atomistic spin-dynamics reproduce experimental data of magnon dispersion of bulk and thin-film systems, the damping parameter, the formation of skyrmionic states, all-thermal switching motion, and ultrafast magnetization measurements.
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Book chapters on the topic "Bulk field measurement"

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Torres-Rincon, Juan M. "Measurement of the Bulk Viscosity." In Hadronic Transport Coefficients from Effective Field Theories, 153–65. Cham: Springer International Publishing, 2013. http://dx.doi.org/10.1007/978-3-319-00425-9_10.

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Friedman, Shmulik P., Scott B. Jones, and David A. Robinson. "Geometrical Factors Affecting the Bulk Electrical Properties of Soils and Rocks: Measurements and Continuum Mean Field Computations." In Continuum Models and Discrete Systems, 81–82. Dordrecht: Springer Netherlands, 2004. http://dx.doi.org/10.1007/978-1-4020-2316-3_13.

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Singh, Devinder, and Kuldeep Chand Verma. "Magnetic Properties of Heusler Alloys and Nanoferrites." In Magnetic Skyrmions. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95466.

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In this chapter, results of our recent investigations on the structural, microstructural and magnetic properties of Cu-based Heusler alloys and MFe2O4 (M = Mn, Fe, Co, Ni, Cu, Zn) nanostructures will be discussed. The chapter is divided into two parts, the first part describes growth and different characterizations of Heusler alloys while in the second part magnetic properties of nano-ferrites are discussed. The Cu50Mn25Al25-xGax (x = 0, 2, 4, 8 and 10 at %) alloys have been synthesized in the form of ribbons. The alloys with x ≤ 8 show the formation of Heusler single phase of the Cu2MnAl structure. Further increase of Ga content gives rise to the formation of γ-Cu9Al4 type phase together with Cu2MnAl Heusler phase. The alloys are ferromagnetically ordered and the saturation magnetization (Ms) decreases slightly with increasing Ga concentration. Annealing of the ribbons significantly changes the magnetic properties of Cu50Mn25Al25-xGax alloys. The splitting in the zero field cooled (ZFC) and field cooled (FC) magnetization curves at low temperature has been observed for alloys. Another important class of material is Nanoferrites. The structural and magnetization behaviour of spinel MFe2O4 nanoferrites are quite different from that of bulk ferrites. X-ray diffraction study revealed spinel structure of MFe2O4 nanoparticles. The observed ferromagnetic behaviour of MFe2O4 depends on the nanostructural shape as well as ferrite inversion degree. The magnetic interactions in Ce doped CoFe2O4 are antiferromagnetic that was confirmed by zero field/field cooling measurements at 100 Oe. Log R (Ω) response measurement of MgFe2O4 thin film was taken for 10–90% relative humidity (% RH) change at 300 K.
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Marrone, Babetta L., and Robert C. Habbersett. "DNA Fragment Sizing by High-Sensitivity Flow Cytometry: Applications in Bacterial Identification." In Flow Cytometry for Biotechnology. Oxford University Press, 2005. http://dx.doi.org/10.1093/oso/9780195183146.003.0011.

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High-sensitivity, single-molecule detection in flow is a paradigm that has been defined at Los Alamos over the last two decades. A recent focus has been on applications of single- molecule detection for DNA fragment sizing using a compact, low-power, highsensitivity flow cytometer (HSFCM). There are three key aspects of our approach that distinguish it from conventional flow cytometry and yield the high level of sensitivity that we achieve: a detector with high photon-detection efficiency, a small probe volume to reduce background noise, and slow flow to provide extended analyte dwell time in the probe volume. An additional factor for applications in DNA fragment sizing is a DNA stain with significant fluorescence enhancement when bound to double-stranded DNA, and low background fluorescence in the unbound state. DNA fragment sizing by HSFCM has important applications in bacterial species and strain identification, where it can replace the cumbersome and time-consuming pulsed-field gel electrophoresis (PFGE) approach routinely used by public health labs for bacterial identification. The revolutionary capability to interrogate single DNA molecules, as well as potentially other submicron-sized biological particles, in a high-sensitivity flow cytometer will provide new scientific insights into cellular and molecular biology and introduce high-sensitivity flow cytometry to a wide variety of new applications in biotechnology. Flow cytometry has enabled major advances in the biomedical sciences by providing rapid, quantitative, and sensitive multiparameter measurements of individual cells and subcellular particles such as chromosomes. This analysis of individual entities produces information on population heterogeneity that is not revealed in ensemble measurements and that allows more precise quantitation of distinct attributes than is possi ble when measurements are done in bulk. However, one limitation of conventional flow cytometry is the inability to measure submicron-sized particles or weakly fluorescent particles labeled with fewer than several hundred fluorophores, primarily as a result of insufficient detection sensitivity. A wide variety of important biological particles, molecules, and molecular assemblies fall into these categories. There have been many reports of bacterial measurement and characterization by conventional flow cytometry, dating back to 1947. In 1979, Steen developed a microscope-based system specifically for applications in microbiology. Many bacteria are large enough to generate a light-scatter signal, which is useful for their detection.
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Laurent, Philippe, Jean-François Fagnard, and Philippe Vanderbemden. "AC Magnetic Measurements on Superconductors." In Advanced Instrument Engineering, 208–22. IGI Global, 2013. http://dx.doi.org/10.4018/978-1-4666-4165-5.ch016.

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This work describes the design and realisation of an apparatus to measure simultaneously the AC magnetic properties and the temperature distribution on the top surface of bulk superconducting samples (up to 32 mm in diameter) in cryogenic conditions (temperature range 78-120 K). First the authors describe the experimental set-up used for simultaneous thermal and magnetic characterization of the sample. Next, the authors describe the practical considerations required for generating the large AC magnetic fields, possibly in the presence of DC fields. Then the authors present the data acquisition system allowing both temperature and magnetic data to be recorded at high a sampling rate.” The performances and limitations of the system are discussed.
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Baer, Tomas, and William L. Hase. "Introduction." In Unimolecular Reaction Dynamics. Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195074949.003.0003.

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The field of unimolecular reactions has witnessed impressive advances in both experimental and theoretical techniques during the past 20 years. These developments have resulted in experimental measurements that finally permit critical tests of the major assumptions made more than 60 years ago when Rice and Ramsperger (1927, 1928) and Kassel (1928) first proposed their statistical RRK theory of unimolecular decay. At the heart of these advances is our ability to prepare molecules in narrow ranges of internal energy, even in single quantum states, at energies below and above the dissociation limit. This has led to detailed spectroscopic studies of intramolecular vibrational energy redistribution (IVR), a process that is intimately related to the assumption of random energy flow in the statistical theory of unimolecular decay. This book is devoted exclusively to the study of state- or energy-selected systems. However, in order to place these studies in the context of the much larger field of unimolecular reactions in general, we provide a brief background of the field up to about 1970. The experimental studies of unimolecular reactions developed in three stages. The early studies involved strictly thermal systems in which molecules were energized by heating the sample either in a bulb (Chambers and Kistiakowsky, 1934; Schlag and Rabinovitch, 1960; Flowers and Frey, 1962; Schneider and Rabinovitch, 1962), or by more sophisticated methods such as shock tubes which were applied to unimolecular reactions by Tsang (1965, 1972, 1978, 1981) and others (Astholz et al., 1979; Brouwer et al.,1983). The drawback of these studies is that molecules were prepared in a very broad (albeit well characterized) distribution of internal energy states. A major advance was the use of chemical activation in the early 1960s in which a species such as CH2 reacted with a molecule, thereby forming an energized species which could either isomerize or be stabilized by collisions (Rabinovitch and Flowers, 1964; Rabinovitch and Setser, 1964; Kirk et al., 1968; Hassler and Setser, 1966; Simons and Taylor, 1969). This approach permitted the reacting species to be prepared in a narrow range of internal energies.
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Kennel, Charles F. "Bimodal Plasma Sheet Flow." In Convection and Substorms. Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195085297.003.0012.

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How does the plasma sheet respond to the complex pattern of waves coming over the poles from bursty magnetopause reconnection events, or to the vortices and other irregular perturbations coming around the flanks of the magnetosphere in the low-latitude boundary layer? It is probably too much to expect that the complex input from the dayside will sort itself out into a steady flow on the nightside, but there has been a seductive hope that, on a statistical basis, the observations of the plasma sheet could be rationalized using steady convection thinking. This hope depends on the belief that the average magnetic field configuration in the plasma sheet actually is compatible with steady convection. The first doubts on this score were raised by Erickson and Wolf (1980), and were subsequently elaborated by Tsyganenko (1982), Birn and Schindler (1983), and Liu and Hill (1985); the“plasma sheet pressure paradox” they posed is the subject of Section 9.2. Theoretical arguments are one thing, measurements are another; the truly important issue is whether the real plasma sheet manifests steady flow. Several groups have searched large data sets to see whether the statistically averaged flow in the central plasma sheet resembles the flow predicted by the steady convection model. This effort has led to a growing but still incomplete comprehension of the statistical properties of plasma sheet transport. Results obtained using ensembles of data acquired by ISEE 1 and AMPTE/IRM will be reviewed in Section 9.3. The unusual distribution of bulk flow velocities suggests that the plasma sheet flow is bimodal, alternating between a predominant irregular low-speed state and an infrequently occurring state of high-speed earthward flow. In search of steady plasma sheet flow, one could also look into substormfree periods of stable solar wind properties. One of the best such studies, in which great care was taken to find periods of exceptionally stable solar wind and geomagnetic conditions, is reviewed in Section 9.4. Even this study found highly irregular and bursty flow.
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Conference papers on the topic "Bulk field measurement"

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Ning, Yanong N., and David A. Jackson. "Recent developments in the field of bulk-optic current sensors." In Measurement Technology and Intelligent Instruments, edited by Li Zhu. SPIE, 1993. http://dx.doi.org/10.1117/12.156363.

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You, Ruquan, Haiwang Li, Zhi Tao, and Kuan Wei. "Measurement of the Mean Flow Field in a Smooth Rotating Channel With Coriolis and Buoyancy Effects." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63123.

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The mean flow field in a smooth rotating channel was measured by particle image velocimetry under the effect of buoyancy force. In the experiments, the Reynolds number, based on the channel hydraulic diameter (D) and the bulk mean velocity (Um), is 10000, and the rotation numbers are 0, 0.13, 0.26, 0.39, 0.52, respectively. The four channel walls are heated with Indium Tin Oxide (ITO) heater glass, making the density ratio (d.r.) about 0.1 and the maximum value of buoyancy number up to 0.27. The mean flow field was simulated on a 3D reconstruction at the position of 3.5<X/D<6.5, where X is along the mean flow direction. The effect of Coriolis force and buoyancy force on the mean flow was taken into consideration in the current work. The results show that the Coriolis force pushes the mean flow to the trailing side, making the asymmetry of the mean flow with that in the static conditions. On the leading surface, due to the effect of buoyancy force, the mean flow field changes considerably. Comparing with the case without buoyancy force, separated flow was captured by PIV on the leading side in the case with buoyancy force. More details of the flow field will be presented in this work.
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Jenkins, Sean C., Igor V. Shevchuk, Jens von Wolfersdorf, and Bernhard Weigand. "Transient Thermal Field Measurements in a High Aspect Ratio Channel Related to Transient Thermochromic Liquid Crystal Experiments." In ASME Turbo Expo 2007: Power for Land, Sea, and Air. ASMEDC, 2007. http://dx.doi.org/10.1115/gt2007-27812.

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Measurements of transient fluid temperature distributions were made in a high aspect ratio (4:1) internally ribbed two-pass channel relating to the measurement of heat transfer using the transient thermochromic liquid crystal (TLC) technique. The temperature field was measured at several positions leading up to and around the 180° bend in a two-passage channel to account for variations in the bulk temperature used as a reference for the transient TLC technique. Results showed that the normalized distribution of the temperature field was time-invariant, an important result for the validation of heat transfer results using the transient TLC method. The normalized fluid temperature field was shown to be independent of the inlet temperature step and relatively independent of channel Reynolds number. Fluid temperature distributions were shown to be consistent over the length of the inlet channel, however, temperature field measurements made downstream of the bend exhibited a strong asymmetry. Finally, local temperature distributions were used to adjust the reference temperature used in calculating heat transfer coefficient distributions and to show the behavior of heat transfer due to 180° bends.
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Ishida, Akihiko, Daisuke Ichimura, and Masahiro Motosuke. "3D Velocity Measurement by Orthogonal-Plane Micro-PIV for Electrokinetic Enhancement of Surface Reaction." In ASME 2013 11th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icnmm2013-73214.

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In microfluidic systems, surface reaction is diffusion-limited because the effect of convection on mass transport decreases due to low Peclet number. It is indicated that an externally induced flow toward the reactive interface is effective to enhance the efficiency of the surface reaction. However, it is difficult to evaluate the flow velocity normal to the substrate, which directly contributes to the enhancement of the surface reaction, due to the monolithic dimension of microfluidic device. This paper reports the development of a 3D flow velocity measurement method by orthogonal-plane micro-PIV to evaluate the contribution of flow distortion by alternating-current electrokinetic phenomena on the reaction enhancement. 3D velocity field is reconstructed from two orthogonal velocity fields measured by 2D micro-PIV with different measurement planes; one is based on normal observation with the measurement plane parallel to the bottom wall and the other is based on a lateral observation with the plane perpendicular to the bottom wall through a sidewall of a fluidic channel made of PDMS (100 × 50 μm). Complete 3D velocity field is determined by scanning the measurement plane in each observation scheme. Validity of orthogonal-plane micro-PIV for the 3D velocity measurement was confirmed by the measurement of three component velocities in a tilt rectangular microchannel. Then, we investigated AC-driven electrothermal (ACET) effect induced by the property gradient of fluid due to temperature nonuniformity under an electric field application. Effective flow structure of ACET for the enhancement of surface reaction, a circular stirring fluid motion which conveys bulk fluid to the surface region, was observed. This stirring motion of fluid could improve the binding opportunities between suspended and immobilized species and result in the promotion of reaction efficiency. It is clarified that 3D flow of ACET contributes to the localized enhancement of the surface reaction efficiency.
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Bageant, Maia R., and David E. Hardt. "Measurement and Process Control in Precision Hot Embossing." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-65788.

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Microfluidic technologies hold a great deal of promise in advancing the medical field, but transitioning them from research to commercial production has proven problematic. We propose precision hot embossing as a process to produce high volumes of devices with low capital cost and a high degree of flexibility. Hot embossing has not been widely applied to precision forming of hard polymers at viable production rates. To this end we have developed experimental equipment capable of maintaining the necessary precision in forming parameters while minimizing cycle time. In addition, since equipment precision alone does not guarantee consistent product quality, our work also focuses on real-time sensing and diagnosis of the process. This paper covers both the basic details for a novel embossing machine, and the utilization of the force and displacement data acquired during the embossing cycle to diagnose the state of the material and process. The precision necessary in both the forming machine and the instrumentation will be covered in detail. It will be shown that variation in the material properties (e.g. thickness, glass transition temperature) as well as the degree of bulk deformation of the substrate can be detected from these measurements. If these data are correlated with subsequent downstream functional tests, a total measure of quality may be determined and used to apply closed-loop cycle-to-cycle control to the entire process. By incorporating automation and specialized precision equipment into a tabletop “microfactory” setting, we aim to demonstrate a high degree of process control and disturbance rejection for the process of hot embossing as applied at the micron scale.
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Venkatesan, Ganesh, and David L. Rhode. "CFD Determination of Pre-Chamber Flow Pertubation Inlet Boundary Conditions for Seal Rotordynamics Models." In ASME Turbo Expo 2003, collocated with the 2003 International Joint Power Generation Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/gt2003-38038.

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A new approach has been developed and utilized to determine the flow field perturbations (i.e. disturbances due to rotor whirl) upstream of a non-contacting seal. The results are proposed for use with bulk-flow perturbation and CFD-perturbation seal rotordynamic models, as well as with fully 3-D CFD models, to specify the approximate inlet boundary flow disturbance values at the computational domain inlet. The radially bulk-averaged disturbance quantities were evaluated in the upstream chamber from nearly 40 cases of geometry/operating conditions. The proposed upstream chamber boundary conditions are applicable for liquid as well as gas seals. For each of the measurement test cases considered, improved agreement with measurements was obtained when using the new boundary conditions, even though there was generally little room for improvement when not using the new boundary conditions. Based on the findings in this study it is recommended that the first-order correlations developed here be used to specify approximate boundary conditions at the domain inlet to be located in the upstream chamber.
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Du, F., C. Moreno, Z. Wang, and C. Saldana. "Incipient Plastic Strain Fields in Material Removal Processes." In ASME 2014 International Manufacturing Science and Engineering Conference collocated with the JSME 2014 International Conference on Materials and Processing and the 42nd North American Manufacturing Research Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/msec2014-4213.

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Knowledge of the plasticity associated with the incipient stage of chip formation is important for understanding the flow field underlying transient material removal processes. The transition from an incipient state of strain to steady-state was investigated in chip formation of copper. Characterization of the flow field was made by image correlation, hardness mapping and microstructure measurement. A framework for describing the incipient straining length in chip formation as a function of process parameters was established and explained by effects of the deformation on shear plane morphology. The present results are potentially useful for enabling better informed design of processing configurations wherein transient flow fields contribute significantly to the overall deformation process, such as in grain refinement methods for bulk materials and micro-mechanical surface texturing methods based on machining.
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8

Aga, Zelalem, and LeAnn Faidley. "Characterization of the Magnetostriction of Magnetorheological Elastomers." In ASME 2008 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2008. http://dx.doi.org/10.1115/smasis2008-516.

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Magnetorheological Elastomers (MREs) are polymer composites comprised of an elastomer matrix material with a filler of magnetic particles. The interaction of the filler particles when exposed to a magnetic field can result in a change in stiffness and a strain. However, the main focus of previous research has been on field induced change in stiffness. The goal of this study is therefore to characterize the magnetostriction (field induced strain) of these materials. The measurement of the magnetostriction of MRE was carried out by placing the specimens in a magnetic field produced by a solenoid coil and measuring the resulting strain using a capacitive sensor. A one cycle sinusoidal voltage was input to the solenoid coil that surrounded the MRE specimen to produce the magnetic field. In order to study the effect of mass percentage of iron filler particles on magnetostriction, specimens with different iron filler composition varying from 10 to 30% were produced. The effect of bulk stiffness of the specimen and the magnitude of applied magnetic field on magnetostriction properties has also been studied. The results reveal that increasing the mass percentage of iron in the specimen increases the magnitude of the magnetostriction. In addition, the magnetostriction of MRE showed dependence on the level of applied magnetic field and on the bulk stiffness of the MRE specimens.
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9

DeSilva, Upul, Richard H. Bunce, and Heiko Claussen. "Novel Gas Turbine Exhaust Temperature Measurement System." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-95152.

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Siemens Energy, Inc. has been investigating the potential of a new approach to measuring the process gas temperature leaving the turbine of their heavy industrial gas turbine engines using an acoustic pyrometer system. This system measures the bulk temperature crossing a plane behinds the last row of turbine blades and is a non-intrusive measurement. It has the potential to replace the current intrusive multiple point measurement sensor arrays for both engine control and performance evaluation. The acoustic pyrometer is a device that measures the transit time of an acoustic pulse across the exhaust duct of the engine. An estimate of the temperature of the process fluid can be made from the transit time. Multiple passes may be made at various radial positions to improve the measurement. The gas turbine exhaust is a challenging environment for acoustic temperature measurement where there can be significant temperature stratification and high velocity. Previous applications of acoustic pyrometers to measure process gas temperature in power plants have been confined to applications such as boilers where rapid temperature changes are not expected and fluid velocity patterns are well known. The present study describes the results of acoustic pyrometer testing in an operating gas turbine engine under load using an active acoustic pyrometer system containing eight sets of transmitters and receivers, all external to the turbine exhaust flow path. This active method technology is based on the temperature dependence of the isentropic speed of sound from the simple ideal gas assumptions. Sound transmitters and receivers are mounted around the exhaust duct to measure the speed of sound. Very sophisticated topographical mapping techniques have been developed to extract temperature distribution from using any where from 2 to 8 sensors with up to 24 paths and 400 points. Cross correlation of sensor results to obtain topographical mapping of gas isotherms in a plane in full engine field tests have been conducted to prove the feasible of this technology on a gas turbine engine. The initial installation of the active acoustic pyrometer system in an engine exhaust was accomplished in 2009. All the tests indicate that the steady state measurements of the acoustic pyrometer system fall within 10C of the measured exhaust thermocouple data. An additional installation on a different model engine was subsequently made and data have been gathered and analyzed. Results of these tests are presented and future evaluation options discussed.
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Niu, Zhe, Yulong Zhao, and Bian Tian. "The Design and Implementation of High Pressure Rectangular Diaphragm Sensor Based on MEMS Technology." In ASME/ISCIE 2012 International Symposium on Flexible Automation. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/isfa2012-7132.

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This paper describes the design and fabrication of a piezoresistive high-pressure rectangular sensor which will be used in the petrochemical industry field. The stress distribution of the piezoresistance on the membrane was analyzed by the Finite Element Method through the ANSYS software. The piezoresistance was fabricated on SOI wafers by the MEMS bulk-micromachining technology and the silicon substrate was bonded with the Pyrex 7740# glass by the anodic bonding technology. The linearity, sensitivity, repeatability and accuracy of the fabricated result were 0.3%, 1.109mV/MPa, 0.41% and 0.57%, respectively. This type of microstructure sensor has advantages of high sensitivity, linearity and accuracy. Meanwhile, the sensor has a wide measurement range because of the rectangular membrane. The piezorsistive high pressure rectangular diaphragm sensor offers several advantages such as, high sensitivity, linearity and accuracy, and additionally, the wide measurement range of the sensor will guarantee its great applications in the petrochemical industry fields.
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