Remote probing probe

Fig. 2.6.5 Hardware for high field NMR remote probe in (c) contains a relatively large saddle-detection. Photographs (a) and (b) show la- coil and is used for (flow) imaging. The detec-boratory-built remote detection probes with tor probe in (d) contains a microsolenoid coil both rf coils built into the same body (c), (d) for optimized mass sensitivity, which is parti-and (e) are detector-only remote probes that cularly useful for microfluidic NMR applica-can be inserted from the top or bottom into the tions. The same probe is shown in (e) with a NMR imaging assembly, so that the well mounted holder for a microfluidic chip that is...

Sampling mode effects The goal was to be able to measure at-line, with no sample preparation at all, using a fiber-optic probe or a remote sampling head. However, the area sampled by the hber-optic probe is much smaller than for the sample transport module. It was found that the remote (probe) spectra were very similar to the static (sample transport) spectra, but the baselines were shifted significantly higher and the absorbance peaks consequently reduced in intensity as before, the characteristic peak positions were not affected. Calibration models developed using spectra obtained with the hber-optic probe performed equivalently to those developed with the sample transport module. 

Sampling method/sampler Laminar airflow Critical 1-6 environments Production areas 1-6 General areas 1-6 Flat Irregular environmental environ, surfaces surfaces Personnel barriers Volumetric 1-6 (SP) Y/N Remote probe possible External power Sample... 

Fig. 14.17). The advantage of a surface analysis technique for this application is obvious. It is easier to examine the surface with a remote probe (X-rays) than to devise a way of having an unmanned spacecraft take a sample for an analytical method that requires elaborate sample preparation. 

In the case of oversized samples (e.g., works of art), substrates with unusual shapes or difficult to get at samples such as board components or recessed sample areas, coatings can be remotely probed using a fiber-optic interface that directs the light from the source into a sampling probe head and thereafter collects the transmitted light into the detector of an IR spectrometer. The probe head (a mini-turized ATR element or a reflectance probe with actual sample interface areas as... 

Figure 4.22 (a) Hollow wave guide schematic and (b) mid-IR FlexIR with remote probes. 

Thermoelectrometry comprises methods for the measurement of resistance or capacitance during heating. Some equipment in this category provides remote probes for in situ monitoring of the curing of thermosets. 

Use of cheap, high efficiency fibre optics (remote probing, 100 m)... 

T. F. Cooney, H. T. Skinner and S. M. Angel, Comparative study of some fibre-optic remote probe designs. 1. Model for liquids and transparent solids, Appl. Spectrosc., 1996, 50, 836-848. 

Another attachment that can be effected to a Raman spectrometer is a remote probe. This consists of a fibre optic cable that passes the laser beam to a sample outside the conventional sampling chamber. This can be of use in many different applications, the most obvious of which is where the sample is too large or complex to fit into the instrument. In vivo biological studies utilize a fibre optic probe for the investigation of human tissue. Industrial process monitoring uses a Raman spectroscopic probe for online quality control during manufacture. 

Wark, D. Q. Hilleary, D. T. (1969). Atmospheric temperature successful test of remote probing. Science, 165, 1256-8. 

Fig. 5.13. Diagram of a Raman spectrometer with a fiber-optic remote probe. (Source Ref. [43].)...

New Aspects for Remote Field Eddy Current Probe Development. 

The development of Remote Field Eddy Current probes requires experience and expensive experiments. The numerical simulation of electromagnetic fields can be used not only for a better understanding of the Remote Field effect but also for the probe lay out. Geometrical parameters of the prohe can be derived from calculation results as well as inspection parameters. An important requirement for a realistic prediction of the probe performance is the consideration of material properties of the tube for which the probe is designed. The experimental determination of magnetization curves is necessary and can be satisfactory done with a simple experimental setup. 

Laser Raman diagnostic teclmiques offer remote, nonintnisive, nonperturbing measurements with high spatial and temporal resolution [158], This is particularly advantageous in the area of combustion chemistry. Physical probes for temperature and concentration measurements can be debatable in many combustion systems, such as furnaces, internal combustors etc., since they may disturb the medium or, even worse, not withstand the hostile enviromnents [159]. Laser Raman techniques are employed since two of the dominant molecules associated with air-fed combustion are O2 and N2. Flomonuclear diatomic molecules unable to have a nuclear coordinate-dependent dipole moment caimot be diagnosed by infrared spectroscopy. Other combustion species include CFl, CO2, FI2O and FI2 [160]. These molecules are probed by Raman spectroscopy to detenuine the temperature profile and species concentration m various combustion processes. 

The sample cells for molecular fluorescence are similar to those for optical molecular absorption. Remote sensing with fiber-optic probes (see Figure 10.30) also can be adapted for use with either a fluorometer or spectrofluorometer. An analyte that is fluorescent can be monitored directly. For analytes that are not fluorescent, a suitable fluorescent probe molecule can be incorporated into the tip of the fiber-optic probe. The analyte s reaction with the probe molecule leads to an increase or decrease in fluorescence. 

Fiber-Optic Probes. Fiber-optic probes provide remote sampling capabilities to Raman instmmentation, are stable, and give reproducible signals. Their historical niche has been in environmental monitoring. More recently these probes have been used in chemical process control and related areas such as incoming materials inspection. 

This procedure offers the possibiUty of remote noncontact velocity measurement, where no probes disturb the flow. It is thus compatible for use with hot or corrosive gases. Commercial laser velocimeters have become weU-developed measurement tools. Examples of laser velocimetry include remote measurement of wind velocity, measurement of vortex air flow near the wing tips of large aircraft, and in vivo measurement of the velocity of blood flow. 

Radiometry. Radiometry is the measurement of radiant electromagnetic energy (17,18,134), considered herein to be the direct detection and spectroscopic analysis of ambient thermal emission, as distinguished from techniques in which the sample is actively probed. At any temperature above absolute zero, some molecules are in thermally populated excited levels, and transitions from these to the ground state radiate energy at characteristic frequencies. Erom Wien s displacement law, T = 2898 //m-K, the emission maximum at 300 K is near 10 fim in the mid-ir. This radiation occurs at just the energies of molecular rovibrational transitions, so thermal emission carries much the same information as an ir absorption spectmm. Detection of the emissions of remote thermal sources is the ultimate passive and noninvasive technique, requiring not even an optical probe of the sampled volume. 

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