What is coning and quartering?
Coning and quartering is a method used by analytical chemists to reduce the sample size of a powder without creating a systematic bias. The technique involves pouring the sample so that it takes on a conical shape, and then flattening it out into a cake.
What is riffle in chemistry?
riffle. (Science: chemical) A trough or sluice having cleats, grooves, or steps across the bottom for holding quicksilver and catching particles of gold when auriferous earth is washed; also, one of the cleats, grooves, or steps in such a trough. Also called ripple. Origin: CF.
What are subsampling techniques?
Subsampling (Fig. 1.36) is a method that reduces data size by selecting a subset of the original data. The subset is specified by choosing a parameter n, specifying that every nth data point is to be extracted.
What is quartering of aggregates?
Quartering is the alternative method of reducing the size of a bulk aggregate sample where a sample divider (riffle box) is not available. The bulk sample should be shovelled to form a cone, and turned over to form a new cone, this being done three times.
What does coning mean?
Coning is when the center connective tissue of the abdomen, the linea alba, protrudes outwards beyond the rest of the abdominal wall. This tends to occur due to diastasis recti, or the normal occurring separation of the six pack abs during pregnancy.
How do you use a riffle splitter?
With Riffle Sample Splitters, a homogenous, dry, free-flowing sample is poured evenly into the hopper / funnel. The material flows through the alternately arranged passages in the opposite direction (chutes / riffle bank) into the two collecting pans under the dividing head outlets.
What is the aim of riffling?
Riffle splitters are typically used in assay and analytical laboratories to reduce the size of samples provided from other sources (crushed rock, soils, powders and so on) to a lot size that is appropriate for the next stage of analytical sample preparation.
How does a riffle box work?
The riffle box is designed so that material poured in the top is divided approximately equally and diverted to two sides; material to one side of the box is discarded and the remainder tested or divided to a smaller sample. Coarse aggregates may be divided while damp, but fine aggregate should be surface-dry.
What is subsample mean?
transitive verb. : to draw samples from (a previously selected group or population) : sample a sample of. subsample.
What is meant by downsampling?
(1) To make a digital audio signal smaller by lowering its sampling rate or sample size (bits per sample). Downsampling is done to decrease the bit rate when transmitting over a limited bandwidth or to convert to a more limited audio format. Contrast with upsample.
What is quartering in construction?
The process of reducing a representative sample to a convenient size, or of dividing a sample into two or more smaller samples for testing, is called quartering. This is a non-mechanical method of reducing a sample.
Why is coning bad pregnancy?
This isn’t necessarily a bad thing, and it’s actually normal during pregnancy. Abdominal coning with an open diastasis, during a crunch exercise. As the baby grows, it causes increased pressure on the woman’s abdominal muscles. This increase in pressure causes the muscles at the front to separate.
How is coning and quartering used in chemistry?
Coning and quartering is a method used by analytical chemists to reduce the sample size of a powder without creating a systematic bias. The technique involves pouring the sample so that it takes on a conical shape, and then flattening it out into a cake.
What is the meaning of the term quartering?
Quartering may refer to: Dividing into four parts: Dismemberment – a form of execution. Hanged, drawn and quartered – another form of execution Coning and Quartering a process for splitting of an analytic sample Quartering the process of diluting an alloy by melting it with some other metal to make dissolution easier.
How are the operations of quartering and sizing achieved?
The operations are achieved by the process of sizing, coning, and quartering. Sizing should be done on the basis of sample weight to particle size ratio which can be determined by the formula Q=Kd2, which has been explained in Section 9.3.4.
Which is more efficient, coning or quartering?
If the process is performed only once, coning and quartering is no more efficient than taking alternate portions and discarding the others. PAC, 1990, 62, 1193.