Closing leg

Open- and closed-leg grain elevators are a primary source of dust explosions. 

In a U-tube manometer with one end closed, the saturated vapour pressure of the manometer liquid in the closed leg is used as the reference pressure. For mercury at room temperature, this pressure is approximately 2 x 10 mbar which is much smaller than the smallest pressure measurable (without additional effort) of approximately 1 mbar Ah = 0.75 mm). Hence the measured pressure difference is taken directly as absolute pressure. The result is independent of gas species. 

In (b), total pressure in the closed leg is Pg + Png which is equal to the atmospheric pressure, P. Equating and solving for Pg yields Pg - Pa Png- The enclosed gas exerts less pressure than the atmosphere, and a lower pressure is obtained by subtracting the pressure difference from the atmospheric pressure. 

This corresponds to the physician s stethoscope case mentioned above, and has been realized [208] by bringing one leg of a resonatmg 33 kHz quartz tiinmg fork close to the surface of a sample, which is being rastered in the x-y plane. As the fork-leg nears the sample, the fork s resonant frequency and therefore its amplitude is changed by interaction with the surface. Since the behaviour of the system appears to be dependent on the gas pressure, it may be assumed that the coupling is due to hydrodynamic mteractions within the fork-air-sample gap. Since the fork tip-sample distance is approximately 200 pm -1.120), tire teclmique is sensitive to the near-field component of the scattered acoustic signal. 1 pm lateral and 10 mn vertical resolutions have been obtained by the SNAM. 

Figure 13 shows a typical iastallation of a differential pressure instmment for closed tanks. Connections from the instmments are made to taps ia the vessel at minimum and maximum levels. Between the instmment and the maximum level tap is a constant reference leg. This leg is filled with Hquid until its head is equivalent to the head of the Hquid ia the vessel at maximum level. The reference leg must remain constant, with no formation of vapor under varying ambient conditions. On some appHcations it may be necessary to fiH the reference leg with a Hquid, such as water or a light oil, that remains stable. If the Hquid used ia the reference leg has a higher specific gravity than the Hquid ia the tank, the resulting difference ia head must be corrected for ia the iastmment. Most differential pressure measuriag instmments are equipped mechanically to suppress this difference. 

The reaction was originally carried out batchwise in large stirred pots each containing about a ton of material. The operators had to watch the temperature closely, and to make sure they did not fall asleep, they sat on one-legged stools, next to the reactors. 

The first thing to note is that the furnace surrounds the sample-holder containing the differential thermocouples. A separate control thermocouple controls the furnace temperature and should be placed as close as possible to the position of the sample holder. Some commercial manufacturers use the Reference leg of the differential thermocouple to control the temperature. However, if you were to build a DTA using the components as shown in 7.1.14,... 

The authors thank Drs Shawn Hochman and David Weinshenker for their insightful comments and expertise that contributed to this work. Special thanks to our close colleagues Drs Glenda Keating and Michael Decker, who contributed much to the body of this work. Dr Rye is supported by USPHS grants NS-36977, NS-40221, and NS-43374, and the Restless Legs Syndrome and Arthur L. Williams Jr. Foundations. 

We can group animals into clusters according to how similar they are, comparing their key characteristics the more closely those characteristics match, the more similar are the two species. The choice of characteristics is inherently arbitrary, but we might include the number of legs, covered in fur or feathers, the speed of movement, size, color, carnivore/ vegetarian, and so on ... 

The OSHA investigation13 found that (1) no process hazard analysis had been performed in the polyethylene plant, and as a result, many serious safety deficiencies were ignored or overlooked (2) the single-block (DEMCO) valve on the settling leg was not designed to fail to a safe closed position when the air failed (3) rather than relying on a single-block valve, a double-... 

The U-tube is permanently or semipermanently deployed in a wellbore to provide the ability to periodically (or continuously) acquire samples. The U-tube is extremely simple, consisting of a loop of tubing, which has a tee at its base, terminating at a check valve that permits fluid to enter the loop of tubing (Fig. 1). A filter at the inlet removes particulates that can interfere with the operation of the check valve. At the surface, the U-tube drive leg is connected to a supply of high pressure N2 that closes the check valve... 

Disperse dyes from the monoazo and anthraquinone classes have been implicated in cases of contact dermatitis. Circumstances common to such cases appear to be heavy depths of these dyes on nylon rather than polyester and occurring in articles of clothing that are in direct contact with the skin, often in areas that are likely to become moistened by perspiration. Hosiery, socks, blouses and close-fitting athletic or fashion wear, such as velvet leggings, are representative of the types of garment where this problem has arisen [1]. 

When a pipeline is to be placed in service, the air in it shall be displaced. In order to avoid the creation of a combustible mixture, a slug of inert gas shall be introduced between the hydrogen and air. The hydrogen gas flow shall then be continued without interruption until all the air and inert gas have been removed from the facility. The vented gases shall be monitored and the vent closed before any substantial quantity of hydrogen gas is released to the atmosphere. Dead-ended legs of the pipeline system that cannot be swept by inert gas must be pressure purged. 

I could never understand why he took it all patiently, unruffled and even cheerfully. She was a terrible looking specimen of humanity with eyes almost closed with edema, a pale and pasty skin, red hair that was so thin that it showed her scalp, and what there was was straight and straggling. Her ankles were thicker than the calves of her legs and... 

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