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Precision balances

Important balancing techniques and concepts to be discussed in the sections to follow include in-place balancing, single-plane versus two-plane balancing, precision balancing, techniques that make use of a phase shift, and balancing standards. [Pg.939]

The most common rule of thumb is that a disc-shaped rotating part usually can be balanced in one correction plane only, whereas parts that have appreciable width require two-plane balancing. Precision tolerances, which become more meaningful for higher performance (even on relatively narrow face width), suggest two-plane balancing. However, the width should be the guide, not the diameter to width ratio. [Pg.939]

Precision balancing requires a G2.5 guide number, which is based on 2.5mm/sec (O.lin/sec) vibration velocity. As can be seen from this, 6.3mm/sec (0.25 in/sec) balanced rotors will vibrate more than the 2.5mm/sec (O.lin/sec) precision balanced rotors. Many vibration guidelines now consider 2.5mm/sec (0.1 in/sec) good, creating the demand for precision balancing. Precision balancing tolerances can produce velocities of 0.01 in/sec (0.3mm/sec) and lower. [Pg.939]

Balances with few such significant figures to the right of the decimal point (zero to three) are often referred to as ordinary balances or top-loading balances (precision is 100 to 1 mg). A top-loading balance is an electronic ordinary balance with a pan on the top, as shown in Figure 3.3. The electronic... [Pg.38]

As Soukup and Mayer have argued recently, "Without question, docimasy, namely, the analysis of ores and alloys of gold, silver, [and] copper, had great significance in Oberstockstall.. . . For anyone who had to examine ores or metal for coins, as well as for those who wanted to know whether their transmutations were finally crowned with success, exact balances, precise observations, and accurate computation were more important than wishes, conjectures, theories, and images." Ibid., 2. [Pg.221]

A stirred cell equipped with a 0.22iuni membrane filter was charged with 30 mL of latex, the dispersion of microsphere. The specific surfrice area was adjusted to 0.19 m per ImL and the ionic strength was calibrated to 0.01. At the constant stirrer speed, buffer solution was introduced into the stirred ceil until steady state flux was attained. Protein solutions were introduced with step of pulse injection. The permeate flux was measured continuously with an electronic balance (Precision plus, Ohaus Co., USA) by a data acquisition system. The electronic balance was connected to a PC through a RS 232C interfece. The surface charge density of microspheres was varied as 0.45, S.94, 9.14 and 10.25, and the stirrer speed was varied as 300,400 and 600rpm. [Pg.448]

Balance Precision A sensitive electronic balance can detect masses of 1 x 10 g. How many atoms of silver would be in a sample having this mass ... [Pg.359]

The relevant classes of balances for pharmaceutical purposes are semi-micro-balances, analytical balances, precision balances and platform or industrial balances [14]. They are categorised by their capacity and readability (Table 29.2) ... [Pg.657]

GFRP samples were weighed with a Mettler AT250 digital balance (precision 0.01 mg). The percent weight change as a function of time was calculated using equation [21.1] ... [Pg.786]

Radionuclides are usually extracted from filtrates of discrete samples (from the Rosette sampler, Gerard bottles or from the ship s seawater supply) by coprecipitation as Fe(OH)3, Mg(OH)2, Mn02, BaS04, PbS04 or Co-APDC. If quantitative recovery cannot be guaranteed, yield tracers are used. The sample volume has to be known accurately. Large volumes can be metered with a water meter (approximately 1 % error). Samples of approximately 25 L can conveniently be weighed on board with a balance (precision approximately 50 g). [Pg.369]

The underlying chemical principle is that life needs to flow. It needs enough of each metal to stick to non-metals a little bit, but not so much that it sticks everywhere and all the time. Life is balanced precisely at the point where there is enough free ion to use its sticky chemistry, but not so much that it cross-links the structures inside the cell. The inherent chemistry of the metal ions forces each cell to have just enough, but not too much, of each metal on hand. In this way, chemical laws of binding shape the concentrations of free metal ions in biology into a V. [Pg.30]

Fig. 15.25. Farinograph (according to Rohrlich and Thomas, 1967). The apparatus consists of a ther-mostated mixer or kneader (1), its blades are driven by an electromotor (2). The reaction torque acts through a lever system (4) of analytical balance precision on the indicator scale (5) simultaneously recorded on a strip chart recorder (6). The movement of the lever system is damped by an oil dash pot (3). The farinogram is a diagram of force versus time... Fig. 15.25. Farinograph (according to Rohrlich and Thomas, 1967). The apparatus consists of a ther-mostated mixer or kneader (1), its blades are driven by an electromotor (2). The reaction torque acts through a lever system (4) of analytical balance precision on the indicator scale (5) simultaneously recorded on a strip chart recorder (6). The movement of the lever system is damped by an oil dash pot (3). The farinogram is a diagram of force versus time...
In general, the owner notes no detailed correlation between the water meter readings and the change in water level in the pool, but he notes that on rainy days, the pool contains more than the expected amount, and on very dry days, less water is present than anticipated. So the owner is led to cover the pool with a tarpaulin. At that point, the owner finds that indeed the change in water level can be balanced precisely with the rates of water passage through the inlet and outlet. [Pg.36]

The 2e appear on both sides of the equation and cancel out when adding the two half-reactions together to recover the full redox reaction. In some cases, the half-reactions don t balance precisely, and it is important to consider that one half-reaction occurs multiple times for every time the other half-reaction occurs. That will ensure that the electrons always balance, and charge is conserved. Highlight 5.4 explains what to do in case of unbalanced numbers of electrons. [Pg.119]

TGA was used to measure the amount of methanol diffused into plain PP film. The specimens were heated from 25 to 120 at 20 C/min then held for 30 min. The balance precision within the TGA was 0.01 mg. Sample amount was about 6 mg. The test started within 5 minutes after the film was taken out of methanol and the liquid drops on the film were wiped off by a tissue. [Pg.2378]


See other pages where Precision balances is mentioned: [Pg.175]    [Pg.39]    [Pg.4]    [Pg.14]    [Pg.67]    [Pg.38]    [Pg.124]    [Pg.448]    [Pg.430]    [Pg.532]    [Pg.660]    [Pg.41]    [Pg.66]   
See also in sourсe #XX -- [ Pg.122 ]




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