Gas pressure measurement

Such systems have the experimental advantage that kinetic data may be obtained by gravimetric or evolved gas pressure measurements. However, these data must be interpreted with care, since gas release is not necessarily concurrent with the solid—solid interaction but may, in principle, be a distinct rate process under independent kinetic control and occur either before or after reaction between the solids. Possible mechanisms to be considered, therefore, include the following. 

H. Joachim H.Ilgen, SS 27, 76-9 121-25 (1932) (Gas pressure measurements using piezoelectric indicator) 10)Marshall 3 (1932) I33 (Closed bomb and pressure measuring devices) ll)Vennin, Burlot Lecorche (1932), 72-87 (Closed vessel and various pressure measuring devices used between WWI WWII in the laboratories of the Commission des Substances Explosives) 12)C. 

High resolution gas pressure measurements based on the evaluation of the refractive index can be performed with a Michelson-interferometer ... 

In most vacuum work where a high degree of accuracy is not required, gas pressures are measured in Torr. Where published results call for the highest degree of accuracy, gas pressures measured in Torr can be coixected for temperature and gravity and converted to pascals using the definition... 

Figure 12-1 Some laboratory devices for measuring pressure, (a) Schematic diagram of a closed-end barometer. At the level of the lower mercury surface, the pressure both inside and outside the tube must be equal to that of the atmosphere. There is no air inside the tube, so the pressure is exerted only by the mercury column h mm high. Hence, the atmospheric pressure must equal the pressure exerted by h mm Hg, or h torr. (b) The two-arm mercury barometer is called a manometer. In this sample, the pressure of the gas inside the flask is greater than the external atmospheric pressure. At the level of the lower mercury surface, the total pressure on the mercury in the left arm must equal the total pressure on the mercury in the right arm. The pressure exerted by the gas is equal to the external pressure plus the pressure exerted by the mercury column of height h mm, or (in torr) = (in torr) + h torr. (c) When the gas pressure measured by the manometer is less than the external atmospheric pressure, the pressure exerted by the atmosphere is equal to the gas pressure plus the pressure exerted by the mercury column, or...

Perhaps the most widely used TG-MS system, which includes DTG. DTA, and gas pressure measurements, is the Mettler thermoanalyzer. The system, which consists of a precision thermobalance, a high-vacuum system, a mass spectrometer, and a DTA measuring system, has been described in detail by numerous investigators (68-73). 

Qi Li-ming, et al. 2007. Analysis on the Gas Pressure Measurement Result Revision on the Basis of Gas Loss (Quantity Before Bore Being Sealed. Journal of China Coal Society 32(l) 60-63. 

The hole is sealed with grouting. The materials for hole sealing is often cement paste, which expands rather than shrinks. The hole is sealed by compressed air grouting device or mud pump. This manometric method applies to gas pressure measure at any condition in the pit, in particular applies to the measure of gas in close distance coal seams and coal seams groups. 

It is a growing trend to use active hole seating to determine the gas pressure of the coal seam in the future gas pressure measurement. 

Provide manometer/pressure gauge for gas pressure measurement. 

First, measurements are fairly sensitive to experimental circumstances, namely the preparation of the sorbent sample, i. e. activation, outgassing or still remnant preadsorbed substances such as water in zeolitic materials. Also gas pressure measurements, i. e. calibration of pressure gauges, leaks in the... 

Manometers are classical and still useful gas pressure measurement devices used also to calibrate semiconductor pressure sensors. Applying the manometers as pressure measurement devices, caution should be taken to prevent the overflowing as well as the spontaneous oscillation of the liquids. To obtain pressure distribution in one glance, the manometers can be assembled and connected to a common-reservoir. 

Figure 8 Frequency response of a particle pressure sensor to the gas pressure change, (a) Setup to test the dynamic response (b) gas pressure (measured by a pressure transducer) and the phase shift. (Campbell and Wang, 1990.) (With permission of Institute...

There are two devices to be set up and coupled for these experiments a gas pressure measurement device and a calorimeter. The gas is manipulated in, and transferred from, a vacuum line. The amount of gas introduced into the calorimeter is obtained by pressure, volume and temperature (PVT) measurements before and after each injection. PVT measurements, the coupling of the vacuum line to the calorimeter cell, and the calorimeter are described below [2]. 

Usually one varies the head of mercury or applied gas pressure so as to bring the meniscus to a fixed reference point [118], Grahame and co-workers [119], Hansen and co-workers [120] (see also Ref. 121), and Hills and Payne [122] have given more or less elaborate descriptions of the capillary electrometer apparatus. Nowadays, the capillary electrometer is customarily used in conjunction with capacitance measurements (see below). Vos and Vos [111] describe the use of sessile drop profiles (Section II-7B) for interfacial tension measurements, thus avoiding an assumption as to the solution-Hg-glass contact angle. 

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