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  • 1
    Electronic Resource
    Electronic Resource
    Spectral characteristics and effects of heat treatment on intrinsic Nd-doped fiber thermometer probes (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 139-145 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A detailed investigation of the practical spectroscopic features and the effect of prolonged exposure to elevated temperatures of an intrinsic Nd:doped fiber optic thermometer probe using the fluorescence decay time technique has been carried out. Results have shown the optimum length for the doped fiber and a maximum operating temperature of 750 °C, beyond which a range of high-temperature "annealing" effects are seen. These are discussed in light of the operation of the thermometers over the range from −196 to 750 °C and potentially above. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148489
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  • 2
    Electronic Resource
    Electronic Resource
    Quasidistributed fluorescence-based optical fiber temperature sensor system (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 146-151 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The use of multiple material fluorescence-based sensors, where each is optimized to a particular temperature range yet is pumped by the same light source, emitting over the same spectral region, makes for a very simple, convenient and promising optical arrangement which can be applied in real-time, quasidistributed temperature sensor systems. The fluorescence lifetime approach, which is an important technique to enable fluorescence emission to be exploited for thermometry, is adopted in the system discussed. An analysis scheme using Prony's method has been reported which enables exponential decays from either single-material or two material and quasidistributed sensors to be deconvolved and thus data and associated measurand information encoded in each individual signal to be recovered. In this work, in the development of quasidistributed temperature sensor algorithms based on Prony's method are used for the estimation of exponential time constants of a convolved triple exponential fluorescence decay, each corresponding to a different-point temperature. Experimental results obtained are presented to justify their use in practical multiexponential fluorescence decay analysis and show a comparison of the Prony method to the Marquardt nonlinear least-squares approximation algorithm to achieve the deconvolution. The computational time for Prony's approach is approximately one-thousandth that of the Marquardt technique while the accuracy achieved using Prony's method is still high enough for practical use. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148520
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  • 3
    Electronic Resource
    Electronic Resource
    Characterization of erbium-doped intrinsic optical fiber sensor probes at high temperatures (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 2924-2929 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The use of rare-earth-doped fibers for high temperature measurement has shown considerable promise. In this work, studies of the key characteristics of the performance of Er-doped fiber-based thermometer probes using the fluorescence decay time technique were carried out. Results showed the effects of fluorescence intensity as a function of doped fiber length and temporal and dopant concentration features of the probes. Annealing effects were seen to occur, and a satisfactory stable performance at up to 1100 °C was reported from this material, yielding improvement on results obtained with Nd-based systems. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149035
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  • 4
    Electronic Resource
    Electronic Resource
    Determination of local high temperature excursion in an intrinsic doped fiber fluorescence-based sensor (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 2930-2934 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A fluorescence-based intrinsic doped fiber temperature sensing system for determining local extremes of high temperatures has been demonstrated in this work. Data on this temperature rise are analyzed using a mathematical relationship, based on a correlation coefficient ratio scheme, to relate to the reduced fluorescence decay time information thus associated with the hot part of the fiber. In schemes incorporating this mathematical analysis, two separate sensor configurations have been demonstrated, one of which is to use short, single lengths of fiber spliced into a network and the other a long single length of doped fiber, using both Nd and Er doped fiber materials. The results show that the correlation coefficient ratio, R, will deviate from and be smaller than unity with the increase of the temperature of the localized region where the heat is applied, providing the mechanism for a simple high temperature excursion detection system. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149036
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  • 5
    Electronic Resource
    Electronic Resource
    Application of singular value decomposition in average temperature measurement using fluorescence decay techniques (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 1716-1723 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Average, rather than point specific temperature measurement is important in a number of industrial situations. In this work, a method to improve this type of measurement using the fluorescence lifetime-related mathematical parameter, the singular value (SV), is discussed in detail. The analysis reported shows that with rare-earth doped fibers used as temperature sensor probe elements, for average temperature measurement, such a system works well especially when the lifetimes obtained from different sensing probes are very close to each other. The SV scheme, based on matrix theory, is important because the average temperature-dependent singular value possesses the characteristics of both high speed and high precision. Using the method, an average temperature sensing scheme is demonstrated in experiments carried out over the region from 20 to 100 °C, in which Nd3+ doped fibers are employed as the intrinsic temperature sensor elements. When two temperature sensing probes are used in the measuring region, the precision determined for the average temperature estimation is ±3.6 °C. When three sensors are employed instead of two, the precision is similar at ±3.4 °C. Results obtained indicate that with more sensor elements used in the sensing region, the accuracy achieved is not diminished due to the averaging effect in the measurement. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148831
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  • 6
    Electronic Resource
    Electronic Resource
    Ytterbium-based fluorescence decay time fiber optic temperature sensor systems (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 4179-4185 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A series of different Yb-doped fibers has been investigated to determine their potential for use as the active elements in fluorescence–lifetime based thermometry, over a wide range from room temperature to 700 °C. Heat treatment ("annealing") has been shown to be necessary in practical applications to achieve consistent and reproducible calibration curves, each of which is consistent with the results of a simple two level model. Each sample studied was found to possess unique sensitivity characteristics, enabling an optimized selection for specific applications. The response of the thermometer and the error in the measurement was found to be, at 〈±5 °C, consistent with the stability of the calibrated oven used. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149267
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  • 7
    Electronic Resource
    Electronic Resource
    Intrinsic doped fluorescence decay-time based measurements—strain and temperature characteristics for sensor purposes (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 4186-4190 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: With current research in "smart" structures driving interest in the development of intrinsic (in-fiber) sensors for simultaneous strain and temperature monitoring, a new sensor approach is presented. In this, the fluorescence decay-time technique, which is familiar as a method of temperature monitoring with a range of materials is extended to investigate the strain sensitivity of an important temperature probe using Nd-doped fiber, in both single and multimode form. For these fibers, strain and temperature sensitivities are presented, "stress annealing" effects are investigated and the potential for compact, multiparameter intrinsic sensors using Nd-doped fiber is discussed. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149241
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  • 8
    Electronic Resource
    Electronic Resource
    Phorbol Myristate Acetate Downregulates the Binding Sites for Colony-Stimulating Factor-1 on Osteoclasts Isolated from Rats (1998)
    Springer
    Calcified tissue international 62 (1998), S. 148-152 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Osteoclasts — Colony-stimulating factor-1 — Colony-stimulating factor-1 receptor — Downregulation — Phorbol myristate acetate.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Colony-stimulating factor-1 (CSF-1) is the growth factor for the cells of the mononuclear phagocytic system and for osteoclasts. We tested whether phorbol myristate acetate (PMA), a phorbol ester activating protein kinase C, modulates the number of binding sites for CSF-1 on isolated rat osteoclasts. PMA decreased binding of CSF-1 to osteoclasts within 60 minutes. The effect of PMA was dose dependent at concentrations between 10−9 M and 10−6 M. The inactive phorbol ester, 4α-phorbol 12,13-didecanoate, had only a slight effect. Since the osteoclast preparation was contaminated with other cells, the action of PMA on the osteoclasts might have been either direct or indirect. In pure osteoclasts harvested by a micropipette, the downregulation of CSF-1 binding by PMA reached only about three-quarters of that in nonpurified preparations. Addition of osteoblastic osteosarcoma UMR106 cells increased the effect of PMA. Antiserum against CSF-1, which was added to osteoclasts contaminated with other cells, mainly osteoblasts, partially inhibited the effect of PMA, but the antiserum had no effect in pure osteoclasts. These data suggest that the effect mediated by osteoblasts or other contaminating cells is due to the release of CSF-1, which is known to downregulate its binding sites on osteoclasts. The direct action of PMA on osteoclasts decreased the binding only to about 40%, in contrast to CSF-1 which completely downregulated the binding. The data also differ from the published results about macrophages. In these cells, PMA downregulates the binding of CSF-1 completely. The CSF-1 binding sites on osteoclasts recovered within 4 hours after removal of PMA, and cycloheximide, an inhibitor of protein synthesis, inhibited the recovery.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002239900408
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