Bottom sampling

Figure 32 Stacked H NMR spectra of the contaminant (top) and fuel delivery system module filter (bottom) samples. 

An alternative operation to sample the coal is to employ bottom sampling, in which coal is sampled as it is discharged from the bottom of hopper cars. Since the coal is sampled in motion, bottom sampling is considered to be an improvement over car-top sampling. 

At each exposed floodplain sediment sample site clear the surface humus and litter to begin with, and then cut a vertical section through the exposed floodplain sediment sequence with a steel spade, thus exposing a clean vertical surface for sampling. If you collect both top and bottom samples, sample the bottom layer first at each sample site, and then the top layer. This procedure avoids cleaning the surface of the bottom layer from fallen top sample material, if the latter is taken first. 

Fig. 2. X-ray diffractogram of the converter flue dust (CFD) and the plasma treated samples produced therefrom sample R—from the reactor wall, sample RB—from the reactor bottom, sample C—from the cyclone. Assignation of peaks Fe, metallic iron M, magnetite W, wustite H, hematite G, graphite.

Figure 9. Partial H NMR spectrum of 13 LiN03 at 213 K. Top sample prepared by solid-liquid extraction using freshly opened CDC13. Bottom sample prepared with water-saturated CDCI3. (Reprinted with permission from ref. 32. Copyright 2004 American Chemical Society.)...

Figure 1. Top Schematic cross section through the cylindrical inhomogeneous capacitor bottom Sample-electrode-fiimace assembly used in the present experiments.

Besides theoretical prediction tools,63 commonly used devices include fluidization segregation testers and sifting segregation testers. The Jenike and Johanson fluidization tester is standardized through ASTM International.64 The tester fluidizes a powder sample (80 mL) in a column of air and allows the particles to settle in the column. The tester has a mechanism to retrieve top, middle, and bottom samples of the settled powder. The sample is then analyzed to determine if there is a property gradient within the column. However, the tester can be improved by making it material-sparing, more efficient, and more reproducible. 

Figure 3.22 Adsorptive stripping voltammograms of chromium in groundwater (top) and soil (bottom) samples, using cupferron as a chelating agent. Top curve a, response for electrolyte curve b, same as curve a but after spiking 20 pL of the sample (500-fold dilution) curves c and d, same as curve b, but after additions of 0.1 pg/I. chromium 20 s adsorption. Bottom curve a, response for the electrolyte curve b, same as curve a but after spiking 5 pL of the soil extract (2000-fold dilution) curves c and d, same as curve b but after additions of 0.5 p/L chromium 15 s adsorption. (Reproduced with permission from Ref. 53.)...

Figure 11.8 Fe P molar ratio in citrate-dithionate-bicarbonate (CDB) extracts in surface and bottom samples of suspended particles in surface (open circles) and bottom (solid circles) samples across a salinity gradient in Chesapeake Bay (USA). (Modified from Conley et al., 1995.)...

Figure 4.8 Photographs showing anthropogenic contamination observed in some G-BASE panned heavy mineral concentrates. Top Sample 307349P showing oxidised lead shot. Bottom Sample 307364P showing steel shot and a flake of paint.

Marine fungi were found in bottom samples in Odessa Bay from northeastern Asia (two species) [13] and an additional five species were recorded in Odessa port in 2006 (Data of B. Alexandrov). 

ASTM D 4057 (1981) describes a way to get a vertical top-to-bottom sample of petroleum products from a storage tank. A stoppered bottle is dropped vertically all the way to the bottom. Then it is unstoppered and pulled up at such a rate that the bottle is 3/4 full as it emerges from the top. Unfortunately, this is difficult even for a seasoned practitioner. Another way to sample vertically is to take samples from the top, middle, and bottom, also discussed in ASTM D 4057. A stoppered bottle is lowered to the desired depth, the stopper is pulled, the bottle is allowed to fill, and the bottle is raised. These latter samples are easier to obtain because they require little expertise. They also incur less extraction error. They do not give a full vertical cross section but give some representation of the different depths. 

Revelle R. R. (1944) Marine Bottom Samples Collected in the Pacific Ocean by the Carnegie on its Seventh Cruise. Carnegie Inst. Wash. Publ., Washington, DC, 556p. 

Abbasi conducted a submicro determination (down to 10 ppb levels) of Sb(III) and Sb(V) in natural and polluted waters and biological materials. The Sb(III) and Sb(V) concentrations obtained were as follows surface sample of reservoir water 0 and 0, near-bottom sample of reservoir water 0.17 and 0.16 ppb, sea water (India) 0 and 0.28 ppb, and polluted water (rubber industry) 0.85 and 1.91 ppb. Total antimony concentrations of goat liver and frog muscle were 0.094 and 0.027 ppb, respectively . ... 

The samples were collected in December 1983 during different phases in the tidal cycles and at different depths. ((S) represents the samples collected at 05 m depth and (B) represents the overlying bottom samples). The 4 sampling stations (Fig. 1) were selected in order to obtain a range from fresh to brackish water. Samples were collected up-river (1,2, 3, and 4) at high tide, and down-river (4 , 3 , 2 , and 1 ) at low tide. The measures of pH and electrical conductivity ratios were measured on-board. The salinity of all samples was calculated from the electrical conductivity ratios [ 1 ]. ... 

The apparatus in Figure 1 is arranged to sample 0.1 m from the sediment-water interface when the polyethylene sampling tube is attached directly to the anchoring weight and 0.5 m below the air-water interface. However, intermediate depths could also be sampled by adjusting the bottom sampling tube to other desired depths. 

For the bottom samples, the agreement between two limiting values is good, and there appears to be little excess fluoride over what would be calculated for H2SiFe. The correlation between the two values for surface samples is good (r = 0.928, 0.001) and statistically signiflcant, but... 

Typical spectra from top and bottom samples of the catalyst bed are shown In Figs. 8-11. The elements detected and approximate sufracc mole percentages are tabulated in Table 3. For comparison, previous results obtained on the fresh catalyst are included alsa Uncorrected elemental scnsitiviiy factors supplied by VG were used tn calculations of surface concentrations for most of the dements. Absolute concentrations may be ofl by a factor of two, but relative concentrations for a given element should be significant better than this. 

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