Bottom sampler

Procedure. Mud Analyses. Sample Collection. Using bottom sampler, take samples by scraping off top inch of mud along three radii, 120° apart, and composite to make at least a 1-quart sample after free water is decanted. Mark sampling points on outside of tank to prevent resampling of same radii. 

Hvorslev, M.J., and Stetson, H.C. 1946. Free-fall coring tube Anew tj e of gravity bottom sampler. Bulletin Geological Society of America, 57 935-950. 

It is undesirable to have single valves opening to the atmosphere at the bottom of tanks unless such valves are normally blanked off. Therefore, sampling the bottom of a tank should be via a dip hatch in the tank top with a bottom sampler. A self-closing dip hatch is recommended. 

While with-in the mobile x-ray system, the waste in the sampler, is contained within a replaceable (and disposable) polyvinyl chloride (PVC) sleeve with a wall thickness of approximately 0.2-inches and a sealed bottom. It was anticipated that the PVC tube or sleeve would, with use, become highly contaminated with waste residues which drip of fall-off the sampler. The sleeve is coated with a conductive coating to prevent static electricity buildup . There are no sources of ignition in this sealed spare. The sampler (and waste) is coupling which includes a positive pressure gasket. This barrier is further isolated by a second barrier consisting of an epoxy coated aluminum sleeve also sealed-off from the main x-ray cabinet and PVC sleeve. There are also no potential sources of ignition in this isolated secondary space as well. 

Sediments from the bottom of streams, rivers, lakes, estuaries, and oceans are collected with a bottom grab sampler or with a corer. Grab samplers are equipped with a pair of jaws that close when they contact the sediment, scooping up sediment in the process (Figure 7.5). Their principal advantages are ease of use and the ability to collect a large sample. 

The regulations require three samples from the treated plot (one from each subplot) and a single sample from the control plot at each sampling interval. For foliage the preferred technique is to collect leaf punch samples. Leaf punch samplers are available in 5-, 2.5- and 1.25-cm punch areas. Common practice requires a sample of 40-5-cm leaf disks to provide a 400-cm sample using both the top and bottom of the leaf disk to calculate sample surface area. 

Terms used, methods of sampling, and sample handling will be different for water and submerged solid and semisolid samples. The methods described earlier (i.e., transect and grid sampling) are also applicable to these situations. However, semisolid samples, such as those obtained from lake bottoms, require a special sampler. 

Sediment samples were collected with a dredge-type sampler from a boat and also with the aid of a diver. One quart glass jars with aluminum foil-lined caps were used for the sediment samples after collection they were placed in a box containing dry ice. The composition of the river bottom sediments varied from coarse sand (>600m) in the center of the river to coarse and fine silt toward the banks. 

With very viscous or semi-solid liquids such as syrups, molasses and massecuite, the sample is taken by means of a cylindrical metal sampler in such a way that proportionate amounts are taken at different depths. With very dense products which may have crystallised sugar at the bottom, it is especially necessary to reach with the sampler the very bottom of the vessel. Several samples are withdrawn and mixed and the sample or samples for analysis (about 200 grams each) then stored in glass bottles with ground stoppers. 

A pipe sampler is an off-the-belt sampler that collects increments from within the stream cross section by means of one or two pipes. The sampling pipes are mounted at an obtuse angle on a horizontal axle positioned at right angles to the direction in which the coal flows and increments are collected through an orifice that is located in the bottom wall of the sampling pipe. 

To sample with airtight coring devices, we must have access to exposed soil, which may be the ground surface, the bottom and sidewalls of an excavation, the stockpile face or side, or soil in the excavator bucket. We may also apply this technique for sampling of subsurface soil brought to the ground level in a split spoon sampler. 

The Kemmerer sampler is a length of pipe with messenger-activated top and bottom stoppers. The liquid flows freely through the sampler, while it is being lowered to a desired depth on a measured line. Once this depth has been reached, a messenger is sent down the line to activate the top and bottom stopper closure. Because the Kemmerer sampler is typically made of brass, which is not an inert material, its use is limited. 

Aquatic Invertebrates. The initial impact of insecticides on most benthic invertebrates in streams is the inability to maintain their position on the streambed resulting in increased numbers being carried downstream in what is termed drift. Invertebrate drift in treated streams is easily sampled by holding a net in the current. Post-spray catches can be compared to both pre-spray diurnal patterns and catches at an untreated upstream station or in an untreated control stream. This method also can be used to document knockdown of streamside foliage-dwelling or arboreal insects if the net is set so as to sample the stream s surface. Impacts on stream invertebrates can also be determined by caging studies and by pre- and post-spray bottom fauna population assessments which either sample the numbers within a given area of natural streambed (e.g., Surber sampler) or on artificial substrates intentionally set in the stream before treatment to be colonized by resident populations. 

Fig. 29. Origin of systematic errors in spite of potentially error-free analysis. On-line sampling setups (top) and time trajectories of limiting substrate concentration during sample preparation in the two paradigmatic setups depending on the actual culture density (bottom). Either a filter in bypass loop is used for the preparation of cell-free supernatant (upper part in top insert) or an aliquot of the entire culture is removed using an automatic sampler valve and a sample bus for further inactivation and transport of the samples taken (lower part). Both methods require some finite time for sample transportation from the reactor outlet (at z = 0) to the location where separation of cells from supernatant or inactivation by adding appropriate inactivators (at z = L) takes place. During transport from z = 0 to z = L, the cells do not stop consuming substrate. A low substrate concentration in the reactor (namely s KS) and a maximal specific substrate consumption rate of 3 g g h 1 were assumed in the simulation example to reflect the situation of either a fed-batch or a continuous culture of an industrially relevant organism such as yeast. The actual culture density (in g 1 1) marks some trajectories in the mesh plot. Note that the time scale is in seconds...

Figure 3-48. Bending motion and a sampler of potential energy functions. Top bending vibration of a linear triatomic molecule, where r is the instantaneous distance between the end atoms and re is the equilibrium distance of the linear configuration (r

The drag sled snrface sampler (Fignre 3.5) is a simple device constructed of a 7.6-cm X 7.6-cm x 1.9-cm thick block of wood or other material, which is used to hold down a 10-cm x 10-cm piece of denim cloth sampling medium as it is dragged across the floor. The bottom of the block is covered with solveut-riused aluminum foil and the denim patch is placed over the foil. Staples or push-pins are typically used to secure the sampling medium to the block. A 3.6kg weight is centered on top of the block to provide a downward pressure of 4500 Pa. The... 

FIG. 19-7 Traversing linear bottom-dump sampler. Courtesy of Harrison R. Cocrper Systems, Inc. Salt Lake City, Utah )... 

Product from the reactor was sent to a stiU, set at about 230°C, with nitrogen stripping gas to cut the effluent stream at about 340°C. Both overhead and bottoms liquids were collected in cans on scales. Gas went through a gas meter and gas sampler for analysis. 

For liquids, there are several ways to apply the principle of correct sampling across the vertical dimension. A tool that uses the same idea as the thief is the coliwasa (Composite Liquid WAste SAmpler), shown in Figure 3.9. They come in various lengths and diameters, depending on the depth and size of the container lot. This hollow column is lowered slowly through the liquid until the desired depth is reached. Then the top and bottom are plugged to retain a core. 

Determination of r and /3. Samples of reservoir oil for analysis are obtained either by recombining surface samples of oil and gas in the proper proportions or by obtaining a sample under reservoir conditions by means of a bottom hole sampler. 

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