Probe development

New Aspects for Remote Field Eddy Current Probe Development. 

As probes must be manufactured individually for each different tube type, the probe development is an important factor for the economic use of the method. The classical procedure of probe development is a combination of experience and experiment. The new probe design is based on the experience with already manufactured probes. For an evaluation of the new design the probe must be manufactured. If the probe design is complicated, for example due to dual exciter coil arrangement or segmented differential detector coil systems, the costs of the development can be very high. Therefore a method for the pre-calculation of the probe performance is extremely useful. 

An important parameter for the probe development is the amplitude of the exciter current, because of its influence on the diameter of the wire... 

Intracellular calcium elevation is monitored by fluorescent chelators developed by Tsien and coworkers. These indicators are loaded into cells the same way the pH indicators are. With Quin-2 (14), one of the first such probes developed, the quantum yield increases about fourfold when Ca binds to it. The second generation of Ca probes, Indo-1 and Fura-2 (15), are now being widely used in a variety of cell types. These probes are in most cases... 

Figure 21 (A) A probe developed to examine the role of nuclear magnetization in the...

The solids circulation patterns were investigated with a force probe developed in-house. Typical force probe responses are presented in Figs. 43 and 44 for a probe located at 0.13 m from the jet nozzle and with different penetrations into the bed for an air tube velocity of 45.7 m/s. Sincetheforce probe is directional, the upward solids movement will produce a positive response from the probe and vice versa, the magnitude of the response being an indication of the magnitude of solids circulation rate. The number of major peaks per unit time is closely related to the actual bubble frequency in the bed. 

Each screening center has medicinal and synthetic chemistry expertise in order to optimize hits identified from HTS campaigns and develop them into chemical probes. Specific capabilities vary, however typical strategies employed include parallel synthesis, computational and informatics analysis, and analytical capabilities such as LC/MS techniques. The structures of novel compounds that are prepared, their synthetic protocols, analytical data and biological data are all available, and samples of final probes developed are deposited into the MLSMR. A Working Group comprised of chemists from each center meets regularly to share information, best practices, and insure optimal use of resources. 

Compared to 18, the anthrylene macrocycle 16b is a more promising building block for squaraine rotaxane fabrication and fluorescent probe development. 

Probe development simpler than wavelength ratiometric... 

Several papers have been devoted to the detection of toxic metal ions. Some of the probes developed for toxic metals include a selective neutral ionophore for lead... 

Recent LC-NMR Probe Developments 7.4.2.1 Cryogenically Cooled Flow Probes... 

Therefore, the ISE potential depends on the CO2 partial pressure with Nernstian slope. Contemporary microporous hydrophobic membranes permitted the construction of a number of gas probes, developed mainly by the Orion Research Company (for a survey see [143]. The most important among these sensors is the ammonia electrode, in which ammonia diffusing through the membrane affects the pH at a glass electrode. Other electrodes based on similar principles respond to SO2, HCN, H2S (with an internal S ISE), etc. The ammonia probe has a better detection limit than the ammonium ion ISE based on the non-actin ionophore. The response time of gas probes depends mostly on the rate of diffusion of the test gas through the microporous medium [77,143]. 

Solvatochromic probes report on the polarity of the local medium through changes in their UV vis absorption spectra. Perhaps the most famous example of these solvatochromic probes is provided by the Ex30 probe developed by Reichardt (Scheme 8). 

Some care must be exercised with this technique, as errors are introduced at very low frequencies and at very high frequencies, as well as for low values of dielectric constant and loss factor. The technique is valid for the frequencies of 915 and 2,450 MHz, for materials with loss factors greater than 1. The temperature range of the probe is limited to approximately 60°C. However, new probe development is nearing completion. Interpretation for lower loss materials such as fats and oils must be treated with caution. Typical open-ended probes utilize 3.5 mm (0.138 in) diameter coaxial line. For the measurement of solid samples, probes with flat flanges may be utilized (Hewlett Packard 1991). 

Fig. 2.5. Head structures of the miniaturized fiber-optic Raman probes developed by Motz et al. (modified from [29])...

Stepwise radical mechanisms have been proposed for the apparent [2 + 2] cycloaddition of disilenes with ketones by Baines et a/.140,141 They have found that the reactions of tetramesityldisilene 1 with trara-2-phenylcyclopropane carbaldehyde (208a) and fra/M,fra/M-2-methoxy-3-phcnylcyclopropane carbaldehyde (208b), a mechanistic probe developed by Newcomb et al.,142 undergo characteristic cyclopropane ring-opening as shown in Eq. (99). 

Figure 7.2.2 Schematic diagram of the flow probe developed by Dorn and co-workers and used for the direct coupling of SFC to NMR (a) insulated glass transfer line (b) glass insert (c) Cu/constantin thermocouple (d) stainless steel equilibrium coil (e) brass shield (f) Helmholtz coil (g) ceramic flow cell (h) brass Swagelok fitting. Reprinted with permission from Allen, L. A., Glass, T. E. and Dorn, H. C., Anal. Chem., 60, 390-394 (1988). Copyright (1988) American Chemical Society...

The use of capillary separations, an NMR probe that contains multiple coils, and the associated capillary fluidics to deliver the samples to and from the coils is the next step in probe development. A future exciting development will be the interfacing of such intelligent NMR probe and fluidic systems with other integrated detection modalities such as fluorescence, absorbance and mass spectrometry to provide an integrated system capable of delivering unprecedented structural information from complex samples. 

The local gas holdup and bubble behavior were measured by a reflective optic fiber probe developed by Wang and co-workers [21,22]. It can be known whether the probe is im-merging in the gas. The rate of the time that probe immerg-ing in the gas and the total sample time is gas holdup. Gas velocity can be got by the time difference that one bubble touch two probes and the distance between two probes. Chord length can be obtained from one bubble velocity and the time that the probe stays in the bubble. Bubble size distribution is got from the probability density of the chord length based on some numerical method. The local liquid velocity in the riser was measured by a backward scattering LDA system (system 9100-8, model TSI). Details have been given by Lin et al. [23]. 

Improvement of the techniques for monitoring local instantaneous concentrations down to the viscous dissipation microscale (e.g. spatial and time resolution of conductivity probes), development of new techniques (e.g. optical, radioactive tracer methods). 

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