Vernier calipers

In this experiment students measure the length of a pestle using a wooden meter stick, a stainless-steel ruler, and a vernier caliper. The data collected in this experiment provide an opportunity to discuss significant figures and sources of error. Statistical analysis includes the Q-test, f-test, and F-test. 

There are two categories of equipment which determine the selection of equipment general-purpose and special-to-type equipment. It should not be necessary to specify all the general-purpose equipment needed to perform basic measurements, which would be expected to be known by appropriately trained personnel. You should not need to tell an inspector or tester which micrometer, vernier caliper, voltmeter, or oscilloscope to use. These are the tools of the trade and they should select the tool which is capable of measuring the particular parameters with the accuracy and precision required. However, you will need to tell them which device to use if the measurement requires unusual equipment or the environmental conditions prevailing require that only equipment be selected that will operate in such an environment. In such cases the particular devices to be used should be specified in the test or inspection procedures. In order to demonstrate that you selected the appropriate device at some later date, you should consider recording the actual device used in the record of results. With mechanical devices this is not normally necessary because wear should be detected well in advance of there being a problem by periodic calibration. 

Pregnant females were sacrificed by carbon dioxide anesthesia on day 21 of gestation the uterine horns were exteriorized through a midline incision in the abdominal wall, and the number and position of live, dead, and resorbed fetuses were noted. After being weighed and sexed, the fetuses were examined for external anomalies the crown-rump length was measured with a vernier caliper. Half of each litter was preserved in Bouin s solution and later examined for soft tissue anomalies (16) the other half was preserved in alcohol, cleared and stained with Alizarin red-S, and examined for skeletal abnormalities (2). 

Ca and Cg) for simplicity. In this case two types of vernier structure are considered as shown in Fig. 2.32. Structure [a] is composed of A- and B-planes, which are stacked alternatively along the h-axis as. .. ABAB. .. Due to the difference between the dimensions of the unit cells of each plane, the unit length of the supercell structure along the c-axis is expressed by eqn (2.7). In structure [b], the structures A and B are mutually interpenetrated. The dimension of the super structure along the c-axis is also expressed by eqn (2.7). In each case, the relation between structures A and B is very similar to that between the main scale and vernier scale in vernier calipers. 

The very hard materials can be checked using the standard pressure settings. For softer materials, this will cause undue distortions. The micrometer or vernier calipers need to be gently passed over the item. The faces of the instrument must just touch the surface. This can be felt through the instrument as a very mild resistance. The measurements will represent the high points on the surface. 

A dial caliper (see Fig. 2.9) is easier to read than a vernier caliper, but this ease comes at a price. An acceptable vernier caliper can be purchased for 30 - 50, and it can be found with metric and English measurements on the same tool. A good-quality dial caliper may cost between 75 and 150, and it shows only metric or English measurements. On the dial caliper, the 10th place is read on the numbers of the dial itself, and the 100th place is read on the lines between the numbers. 

Another common tool for length measurement is the micrometer. Like the vernier caliper, in the United States, it is typically made with English measurements. Whereas the caliper can provide precision measurement (to 0.002 in.), you need a micrometer for greater precision ( 0.0001 in.). 

Blake measured a piece of steel three times using Vernier calipers. He recorded values of 13.62 mm, 13.53 mm, and 13.55 mm. His lab partner Ayako measured the same piece of steel. She recorded values of 13.45 mm,... 

Should it be necessary to measure the outside diameter of any glass tube to some reasonable degree of accuracy then a vernier caliper should be used. 

The extended jaws of a vernier caliper gauge are used to measure the bore or inside diameter of mbes in the same way. The bore of small diameter and capillary tubes can easily be measured with a taper gauge (Fig. 2.2). 

FIG. 2.1. (Left) (a) Vernier scale set at a reading 3.45 cm. (b) A typical Vernier caliper gauge, (c) Shows the coixect angle for accurate measurement of tube diameters, (d) An incoirect angle, which will result in enors of measurement. 

Artificial lighting over the glassblowing bench and machinery can be provided by. fluorescent tubes which reduce contrast and shadows. Additional lighting may be required where drawings and sketches are made, and for reading vernier calipers or a micrometer. 

The tumor growth is measured by vernier caliper and the tumor volume is calculated as per the formula 0.5 (length x widttf). 

Use the vernier calipers to measure the length of the piece of PTFE tubing, which should now be closer to 12 mm in length. 

The angle of the abduction-adduction axis with respect to the flexion-extension axis is 84.8 12.2°. The location and angulation of the T -wires of the axes with respect to the bones were measured, a, f ) directly with a goniometer. The positions of the pins in the bones were measured T,L) with a Vernier caliper. 

Experimental apparatus Temperature Chamber, plastic mould, ruler, vernier caliper, hacksaw, knife. 

The most common instrument using the above principle is the vernier caliper (see Fig. 6.4). These instruments are capable of external, internal, step and depth measurements (Fig. 6.5) and are available in a range of measuring capacities from 150 mm to 1000 mm. 

Dial calipers (Fig. 6.7) are a form of vernier caliper where readings of 1mm steps are taken from the vernier beam and subdivisions of this are read direct on a dial graduated in 0.02 mm divisions. 

Vernier calipers Large measuring range on one instrument. Capable of internal, external, step and depth measurements. Resolution of LCD model 0.01 mm... 

State the types of measurement which can be carried out using a vernier caliper. 

Measuring devices used to determine if the part meets customer specifications, including micrometers and vernier calipers. 

At first, core was measured with a vernier caliper to get its diameter and length, then it was vacuumpumping and saturated by formation water. After that, the core was put into the core holder to plus confining pressure 2.0 MPa. When the process was turned on, core was injected displacement of formation water forward, core was flowed the displaeement fluid more than 10 times the pore volume until the flow was stable. The core permeability K was calculated, then 2 PV the gel... 

The vernier caliper does not comply with this principle (Fig. 6.2). To ensure greatest accuracy of measurement, the workpiece being measured should be moved as close to the main beam as possible. The vernier depth gauge, however, does comply with Abbe s principle. 

Many of the electronic measuring instruments outlined in this chapter, e.g. vernier calipers, micrometers and dial test indicators, can be equipped to output data either through available data cables or by wireless transmitters/receivers. This data can be printed out or sent to a computer and collected and used by quality control to provide statistical information or for the generation of inspection certificates. 

Although the vernier caliper is extremely versatile in its ability to carry out external, internal, step and depth measurements, calipers with special jaws are available for special purpose applications, a few of which are shown in Fig. 6.11. 

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