Experimental monitoring techniques

Experimental monitoring techniques for polymer electrolyte membrane fuel cells... 

Experimentally, this technique is very similar to the TDI technique described above. A laser beam is incident normally on a diffraction grating or a preferentially scratched mirror deposited on the surface to obtain the normally reflected beam and the diffracted beams as described above. Instead of recombining the two beams that are located symmetrically from the normally reflected beam, each individual beam at an angle d is monitored by a VISAR. Fringes Fg produced in the interferometers are proportional to a linear combination of both the longitudinal U(t) and shear components F(t) of the free surface velocity (Chhabildas et al., 1979), and are given by... 

The monitoring techniques are used to obtain the absolute rate constants of DPC with other substrates (Q) known to react with triplet carbenes. The experiments are carried out at several reagent concentrations and the experimental pseudo-first-order rate constant, k bs, is plotted against the substrate concentration. It can be shown that feobs is expressed by Eq. 22... 

It is clear that a core-hole represents a very interesting example of an unstable state in the continuum. It is, however, also rather complicated [150]. A simpler system with similar characteristics is a doubly excited state in few-body systems, as helium. Here, it is possible [151-153] to simulate the whole sequence of events that take place when the interaction with a short light pulse first creates a wave packet in the continuum, including doubly excited states, and the metastable components subsequently decay on a timescale that is comparable to the characteristic time evolution of the electronic wave packet itself. On the experimental side, techniques for such studies are emerging. Mauritsson et al. [154] studied recently the time evolution of a bound wave packet in He, created by an ultra-short (350 as) pulse and monitored by an IR probe pulse, and Gilbertson et al. [155] demonstrated that they could monitor and control helium autoionization. Below, we describe how a simulation of a possible pump-probe experiment, targeting resonance states in helium, can be made. 

For positive identifications by GC/MS, the full mass spectrum of a tentatively identified component was compared to the mass spectrum of an authentic sample. If the spectra were identical, within experimental error, and if the gas chromatographic retention times of standard and unknown components on a 30-meter SE-54 fused silica capillary column agreed within two seconds, the identification was considered positive. When the amount of material present was insufficient for detection using full scan GC/MS techniques, the more sensitive single and multiple ion monitoring techniques were employed. Confirmation in these cases consisted of coincidences of retention times of mass chromatograms of the unknown and of the authentic sample. For chlorinated materials, the molecular ions contained additional information about the chlorine isotope distribution. Confirmation in those cases included the correct isotope... 

Experimentally the technique is simple since the sample may be irradiated from time to time and the emission intensity measured by a photomultiplier over a period of tens of seconds (Lange et al, 1998). However, these studies confirmed the limited usefulness of CRL alone for real-time monitoring since the emission is significant only in the glassy state, so this technique cannot detect the gel point for the majority of networks. When combined with other luminescence methods it has potential use because it is independent of the atmosphere and is readily adaptable to fibre-optics. 

The proposed DC pulse response monitoring technique is of potential interest in monitoring the contaminant level of the tesed media. This NDT technique is an economic test method as it saves time and effort. A simplified test is done in-sltu. The sensing probe is a simple pure copper write pairs ( the wire cell. 111). The experimental conditions should be fixed so the contaminant concentration will be the only test parameter. The electrode separation is fixed.The the cross section of the wire electrodes is also constant. Fresh metal surface is used in every experiment by simply cutting the end of the wire pairs by a sharpe shear. 

Mazurek, D. F. and DeWolf, J. T. Experimental study of bridge monitoring technique. Journal of Structural Engineering (ASCE) 116(9) (1990), 2532-2549. 

Microfluidic and nanofluidic chips have a wide range of applications in the chemical, biomedical, environmental, and biology areas, where a variety of chemical solutions are used. With the development of microfabrication technology, many new materials such as PDMS and poly (methyl methacrylate) (PMMA) are also employed for chip fabrication. Since each pair of sohd-liquid interface has its unique zeta potential and electroosmotic mobility, which have significant influences on flow control in such small-scale devices, it is very important to experimentally determine these two parameters using the current monitoring technique in order to develop microfluidic and nanofluidic devices for various applications. 

To characterize the electroosmotic mobility of the polybrene surfaces, we performed a series of experiments using the well-established current monitoring technique. In all our experiments, a 25 mM sodium carbonate/bicarbonate run buffer with pH 9.0 was used. Details of the experimental technique can be found in Sze et al. [11]. Briefly, however, to begin, the buffer solution was diluted to 95 % of its original concentration and introduced into a PDMS channel sealed to a glass surface which had undergone the polybrene surface treatment described above. 

Zeta Potential Measurement, Fig. 2 Schematic of the experimental setup for the current-monitoring technique (a)... 

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