Tube sampler

The first indication of breakthrough of the C02 occurred in samples from all 3 U-tube samplers on 17 July, 2008 with slightly elevated C02 content and the presence of tracers. In mid-August, U2 became gassy and the pH dropped significantly. There was no coincident change in either the alkalinity or cation concentrations. By early September, U2 had converted entirely to gas lift. Over the same time frame, as the pH decreases, the per cent of C02 in the U2 samples (for gas exsolved from the water sample through decrease from formation to atmospheric pressure) increased from 4% to >40%. 

Breath (exhaled air) Collection using modified Haldan-Priestly tube sampler collection on adsorbent traps CS2 desorption GC 0.015 mg/m3 (1 L sample) 94.6-99.4 Periago et al. 1991... 

A rotary car dumper system (tube sampler) consists of several large-diameter tubes, each with one or two openings that are attached to a rotary car dumper. The openings are located in the path of the coal as it is discharged from the railcar. If, as has been claimed, the tubes collect coal predominantly from the top and far side of the car, the method is susceptible to bias because of the potential segregation of the coal constituents. 

Gibson, L.T., Cooksey, B.G., Littlejohn, D. and Tennent, N.H. (1997b) A diffusion tube sampler for the determination of acetic acid and formic add vapours in ambient air. Analytica Chimica Acta, 341, 11-19. 

During the cruises in the 1950s and 1960s, oceanographic measurements were performed by means of reversing thermometers (Wolf, 1959) and Nansen bottles. Since 1974, the seawater was collected in a rosette of tube samplers combined with the CTD (Voigt et al., 1976 Seehase, 1980). Between 1951 and 1960/1961, currents were measured by means of Ekman-Merz current meters (Helm, 1968). 

Brown et al. (1992) measured toluene, xylenes, decane and the TVOC concentrations in the air of 100 homes using the Perkin-Elmer tube packed with Tenax TA and a 4 week exposure period. Investigations of the influence of exposure time on net diffusive uptake rate have shown that for a more volatile VOC, such as benzene, the uptake rate is lower for 6 weeks than for 3 weeks exposure periods. There was no effect of exposure period on uptake for the less volatile compounds such as undecane. Brown and Crump (1993) further examined the influence of exposure period by exposing the tube samplers for periods of up to 7 months. No further decline in uptake rate with exposure period occurred for benzene after 5 months and no significant decline in the rate for undecane occurred until exposure periods exceeded 5 months. 

Grab samples provide iniAal information and periodic checks for surface water or water supply systems. The simplest collection from surface water is bottle or dipper submersion. These methods are effective for collecAng water near the top of the water column. To collect grab samples far below the surface, one needs an extendable tube sampler with a check valve to All the tube with the sample. 

Figure 3.5. Split tube sampler for obtaining samples from SPT tests.

The general-purpose open-tube sampler, U100. 

Apparatus—A typical extended-tube sampling assembly is shown in Fig. 7. The extended-tube sampler consists of a flexible tube connected to the suction of a... 

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