Field measurements experimental setup

In addition to Ti and T2, which reflect the rotational motion of water, NMR can also be used to measure the translational motion of water. If an additional, relatively small (compared to B0), steady magnetic field gradient is incorporated into a pulsed NMR experimental setup, a translational diffusion coefficient (D, m2/s) can be measured (called pulsed field gradient NMR). 

Up to this point, water mobility values obtained are average values for an entire sample. However, if magnetic field gradients in the x, y, and z directions are incorporated into a pulsed NMR experimental setup, the spatial distribution aspects of water mobility (7), T2, and D) can also be measured via the use of magnetic resonance imaging (MRI) techniques. 

Arrange with your teacher to plan and perform a field investigation using the experimental setup from this experiment to measure the background level radiation at various points around school or around town. Propose an explanation for your findings. 

Fig. 3. Experimental setup for field measurements without obstacles.

Fig, 6 shows the experimental setup to measure and register concentration fluctuation in the field. The FID device is mounted on a wheelbarrow to reach any position in the field. The ambient air is continuously pumped... 

Cl in conjunction with a direct exposure probe is known as desorption chemical ionization (DCI). [30,89,90] In DCI, the analyte is applied from solution or suspension to the outside of a thin resistively heated wire loop or coil. Then, the analyte is directly exposed to the reagent gas plasma while being rapidly heated at rates of several hundred °C s and to temperatures up to about 1500 °C (Chap. 5.3.2 and Fig. 5.16). The actual shape of the wire, the method how exactly the sample is applied to it, and the heating rate are of importance for the analytical result. [91,92] The rapid heating of the sample plays an important role in promoting molecular species rather than pyrolysis products. [93] A laser can be used to effect extremely fast evaporation from the probe prior to CL [94] In case of nonavailability of a dedicated DCI probe, a field emitter on a field desorption probe (Chap. 8) might serve as a replacement. [30,95] Different from desorption electron ionization (DEI), DCI plays an important role. [92] DCI can be employed to detect arsenic compounds present in the marine and terrestrial environment [96], to determine the sequence distribution of P-hydroxyalkanoate units in bacterial copolyesters [97], to identify additives in polymer extracts [98] and more. [99] Provided appropriate experimental setup, high resolution and accurate mass measurements can also be achieved in DCI mode. [100]... 

Similar measurements were carried out using an external electric field [72], Some differences in morphology and optical properties were measured, depending on the direction of the field with respect to the substrate. It is not clear, from the experimental setup, why the field should influence the deposition, since the field is external and should drop across the air and the glass walls of the reaction vessel. 

Figure 9.6 Experimental setup for measuring the angular distribution of the scattered light at different temperatures and externally applied electric fields. L is a He-Ne-laser, A/2 a half-wave retarder plate, P a Glan-Thomson prism, BS a beam splitter, PDl and PD2 are photodiodes and HV the high voltage amplifier. The sbn sample with 0.66 mol% Cerium is placed on a stack of Peltier-elements to control the temperature.

Figure 39 (a) Schematic representation of an experimental setup for measuring of three-dimensional anisotropy of the magnetic field effect on photoconductivity (C—crystal, M—mirror), (b) Orientation of the magnetic field B with respect to the crystal axes (a, b, c ). From Ref. 248. 

Figure 45 Schematic drawing of the experimental setup to measure EL output in magnetic field (B). This is a topical view of an Alq3 emitter based LED placed between the pole pieces (N, S) of an electromagnet in a way that magnetic field is parallel to the surface of the sandwich DL EL cell, and the electrofluorescence flux (/z/ d) leaves the cell perpendicular to B. Adapted from Ref. 301.

Describe a simple experimental setup involving a condenser by which the applied electric field E0 may be held fixed on insertion of test bodies, and describe a method for determining E0 in terms of simple experimental measurements and calculations. 

The application of laser Doppler velocimetry (LDV) to measure the electrophoretic mobility n of charged colloidal particles is known as laser Doppler electrophoresis (LDE). In a typical LDE experiment, an applied electric field drives the collective motion of charged colloidal particles. The particles pass through an interference pattern created by a dual-beam experimental setup (Section III.A.2). The collective electrophoretic velocity of the particles is then determined via intensity- or spectrum-based analysis of the scattered light, and the electrophoretic mobility n is calculated by dividing the velocity by the applied electric field strength. 

Even the elementary presentation given here makes it clear that transport-number measurements in fused salts are based on the transfer of the fused salt from the anode to the cathode compartment. The quantities measured are weight changes, the motion of indicator bubbles, the volume changes, etc. Some basic experimental setups shown in Fig. 5.42 include the apparatuses of Duke and Laity, Bloom, Hussey, and other pioneers in this field. 

Although in principle every experimental setup that measures the field dependence of the magnetization or a derivative of M could be used to observe the dHvA effect, usually an apparatus with a very high sensitivity has to be designed to resolve the oscillations. An overview of the different experimental techniques is given in Ref. [249], Two main realizations used to detect dHvA oscillations in organic superconductors are the torque and the modulation-field method. 

Fig. 24. Experimental setup for simultaneous measurements of temperature and NO concentration fields in a research SI engine.

The motion of the droplet in an applied electric field distorts the relationship between the charged center and the outer layer to create a dipole. With this simplistic view, it is possible to understand the principle behind electrophoretic mobility, whereby the relative motion of particles or emulsion droplets is measured with an applied electric field. These measurements often depend upon microscopic observation of the droplet motion in the applied electric field and a calculation of droplet velocities to determine their electrophoretic mobility. Figure 11 is a schematic of a typical experimental setup. 

The Nernst signal is measured by an experimental setup shown in Fig. 23a a temperature gradient VF is created in the x-direction, and a magnetic field B is applied in the z-direction. Due to the flow of loop currents, Efic appears in the y-direction and exerts force on electrons then, a real electric field develops to balance the fictitious electric field (E = -Egc) as in the Hall effect measurement. The Nernst signal is defined as the developed electric field in the j-direction, Ey, divided by... 

When the solid phase is fixed (e.g., as a capillary, membrane, or porous plug), a forced flow of liquid induces an electric field. The potential difference is sensed by two identical electrodes. The streaming potential or streaming current can be used to determine the potential. The streaming potential and electro-osmosis can be observed in similar experimental setups, except that the natures of the force and the flux are reversed. Thus, the recommendations and limitations discussed in Section 2.1.2 also apply to measurements based on the streaming potential. For example, the instrument cell induces a streaming potential, which may contribute substantially to the result of the measurement. A linear dependence between the potential obtained by electrophoresis and the streaming current measured by a commercial apparatus was observed in... 

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