Temperature constant, and

The ability to smell a solute relies on it having a vapour pressure above the solution. Analysing the vapour above a gravy dish shows that it contains molecules of both solvent (water) and solute (gravy), hence its damp aroma. The vapour pressures above the gravy dish do not alter, provided that we keep the temperature constant and maintain the equilibrium between solution and vapour. 

If you take a gas at an initial volume (VJ) and pressure (P ) (amount and temperature constant) and change the volume (V2) and pressure (P2), you can relate the two sets of conditions to each other by the equation ... 

The crystallizer was an agitated vessel with an Inside diameter of 9.0 cm and a volume of about 1 1. It was equlppet with four vertical baffles, a water jacket to keep the solution temperature constant, and a nozzle through which nitrogen gas was Introduced In several experiments to suspend a speed crystal more effectively In the solution. Agitation was accomplished with a 5.0 cm stainless steel marine propeller having three blades driven by a variable speed motor. 

If there is no fluctuation of laser intensity, we have to measure /q only once. Actually, the envelope of laser pulses changes in a relatively long time range (typically from several minutes to a few tens of minutes) because of the change of environmental factors such as room temperature and coolant temperature. There is also an intensity jitter caused by factors such as the mechanical vibration of mirrors and the timing jitter of electronics. Furthermore, in our system, the laser system is located about 15 m from the beam port to prevent radiation damage to the laser system. (Later, it was moved into a clean room, which was installed in the control room to keep the room temperature constant and to keep the laser system clean. The distance is about 10 m.) Therefore it is predicted that a slight tilt of a mirror placed upstream will cause a displacement of the laser pulse at the downstream position where the photodetector is placed. 

The main reason why this procedure has not been developed commercially is that during the precipitation of nitrostarch by means of sulphuric acid a sticky intermediate product separates. This is difficult to mix, hence it is not easy to keep its temperature constant and correct, and its composition uniform. In consequence... 

We are now ready to expand our discussion of phase equilibria to consider composition as a variable. In doing so, we will usually hold temperature constant and see the effect of composition (usually mole fraction) on the equilibrium pressure (or pressure on the equilibrium mole fraction) or we will hold pressure constant and describe the relationship between temperature and mole fraction. 

The rate of a reaction is generally a function of the temperature and concentrations of reactants, products and other substances if present. The kinetic equation thus obtained is commonly called the rate equation or the rate law. To find the form of the kinetic equation and the values of its constants is the main task of the kinetic analysis. The first stage of the procedure consists in an experimental measurement of the reaction rate or the conversion in an adequate region of experimental variables. It is advisable to keep the temperature constant and to vary the concentrations this may be repeated for other temperatures if the tern-... 

The two main problems in the design of batch reactors for quantitative kinetic studies are effective removal or supply of heat to keep the temperature constant, and establishment of a sharp zero time. 

If, instead of keeping the volume constant, we keep the temperature constant and allow the volume to vary, we obtain on differentiation of the expression, TrfS = dXJ + pdv, with respect to volume TDS/hzi = DU/Dzi + p... 

Expansion methods are often used for measuring gas densities. In these methods, a sample is expanded from a small volume to a larger volume (where the ratio of volumes is accurately known), holding the temperature constant and measuring the pressure ratio. Typically, multiple expansions are used (a successive expansion technique known as the Burnett method is popular), with the final state being at a pressure sufficiently low that the density is accurately known by other means (such as correction of the ideal-gas law by the second virial coefficient). The Burnett expansion method may achieve uncertainties in density as low as 0.01%. 

J of heat (from the thermostatic bath maintaining the system temperature constant and... 

Temperature As with any chemical reaction, temperature affects methane production. Like the bacteria in our own bodies, the bacteria in the digester are most efficient between 35°C and 37°C. An external heat exchanger, combined with insulation around the digester chamber, help to keep the temperature constant and within the optimal range. 

Summarizing, we can trace back the important thermodynamic functions regarding an open system to the simple internal energy of a corresponding gathered closed system. We summarize the situation in Table 6.1. The last entries B and I in Table 6.1 are somewhat uncommon, however straightforward. Similar to a thermostat that keeps the temperature constant and a manostat that keeps the pressure constant, a chemostat is a device that keeps the chemical potential constant, even when matter enters it. The chemostat is a device with the property d/r/dn 0. In fact, commonly the term chemostat is used for a continuous bio-reactor [6, 7]. By the continuous feed of nutrients, the chemical conditions and thus the chemical potential of the contents are kept constant. 

An apparatus called Gnomix was constructed in 1976 by Zoller et al. [1]. The sample sits under mercury, which enables experiments in both solid and liquid phases. One can keep the temperature constant and vary the... 

In order to get dUldV), we hold the temperature constant and divide both sides by dV. We get... 

We use this device to observe the phase(s) present at various temperatures, pressures, and volumes. We arbitrarily decide to systematically decrease the volume while holding the temperature constant, and we record the pressure and the phase(s) present. Table 4.1 contains the results of one such experiment. 

Cholesteric liquid crystals can be used to measure the absolute temperature of a process provided proper calibration can be performed. Several calibration techniques have already been developed. Perhaps the most obvious is to keep the system temperature constant and measure the reflectance at several points with a spectrophotometer. 

At this point we decide to keep the temperature constant and set dT = 0 this leaves... 

The similarity between the DTA and DSC analyses lies in the fact that both evaluate temperature constantly, and the differences between them are that DTA performs a qualitative analysis of thermal events detected in the sample and DSC is able to quantify these events. However, DSC and DTA do not give absolute results because they measure heat flow dynamically, which hinder obtaining more accurate results since the analyses are not performed imder thermal equilibrium [21]. 

So theoretically, drains should behave differently in the northern and southern hemispheres. Why don t we observe this in reality The reason is that the Coriolis force is very, very small. The force of gravity is 10 million times stronger [18] Only under very carefully controlled conditions has this effect on drains actually been observed [19]. These scientific observations were made on carefully constructed vats of water with perfectly cylindrical drainpipes that were unplugged without disturbing the water. The scientists also found it necessary to eliminate any air currents in the room, keep the temperature constant, and wait for more than 24 hours after the vats were filled in order to see the expected vortex formed. So, we don t see these differences in drain vortices because our drains are far from perfect, and the way we fill the sinks imparts a clockwise or counterclockwise circulation that the liquid water "remembers" for a long time. 

From a thermodynamic point of view, molecular dynamics samples the microcanon-ical ensemble. In order to incorporate canonical thermal fluctuations by coupling the polymer system to a heat bath of canonical temperature T by means of a thermostat, Newton s equations of motion must be modified. Not the system energy E has to be constant, but the canonical expectation value ( ) at the given temperature. Thus, the task of the thermostat is twofold to keep the temperature constant and to sample the thermal... 

An alternative way to separate radiation from the object under study from that of the instrument is to hold the instrument temperature constant and occasionally intersperse measurements of deep space. For most purposes deep space is a nonemitting sink. The weak emission of the cosmic background ( 2.7 K), of stars, and of galaxies is negligible compared with that of objects in our Solar System. To cancel instrument emission one subtracts deep space readings from those of the object of interest. Deep space observations must occur often enough so that the effect of a residual drift in the instrument temperature, and in atmospheric conditions in case of ground-based observations, can be kept small in comparison with the planetary radiance to be measured. Deep space observations must not occur too often, however, so that data collection can proceed undisturbed in between space observations. The optimum duration of planetary and space measurements depends on the planetary intensity, the instrument temperature, and on the thermal time constants of the components involved. 

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