Compositional causes

Thermodynamic Isotope Effect. The change in equilibrium composition caused by isotopic substitution. 

Thermal Conductivity Detector In the thermal conductivity detector (TCD), the temperature of a hot filament changes when the analyte dilutes the carrier gas. With a constant flow of helium carrier gas, the filament temperature will remain constant, but as compounds with different thermal conductivities elute, the different gas compositions cause heat to be conducted away from the filament at different rates, which in turn causes a change in the filament temperature and electrical resistance. The TCD is truly a universal detector and can detect water, air, hydrogen, carbon monoxide, nitrogen, sulfur dioxide, and many other compounds. For most organic molecules, the sensitivity of the TCD detector is low compared to that of the FID, but for the compounds for which the FID produces little or no signal, the TCD detector is a good alternative. 

In a batch reactor, the relative monomer concentrations will change with time because the two monomers react at different rates. For polymerizations with a short chain life, the change in monomer concentration results in a copolymer composition distribution where polymer molecules formed early in the batch will have a different composition from molecules formed late in the batch. For living polymers, the drift in monomer composition causes a corresponding change down the growing chain. This phenomenon can be used advantageously to produce tapered block copolymers. 

The limit of detection for this instrument is about 10 pg/ ml for polystyrene in 2-butanone,163 which is close to two orders of magnitude higher than that of the deflection-type DRI. Moreover, the response of the ELSD is linear over only two decades in concentration.163 The ELSD is a useful backup detector when the DRI or UV detectors are not appropriate, e.g., when the UV absorbance or RI change is a function of copolymer composition as well as concentration or in gradient elution systems where changes in solvent composition cause drift in baselines of the UV and DRI detectors. Compounds about as volatile as the solvent are poorly detected by ELSD. 

An emulsifiable concentrate is prepared from pesticides that are soluble in common organic solvents, such as xylene and kerosene. Using emulsifiers in the composition causes the formulation to disperse into small particles, called an emulsion, when diluted in water. 

In the La2 xAxCu04 series where A may be Ba, Sr, Ca, or Na, Tc initially increases with increasing x but the Cu-O distance is also decreasing. Which should we really be correlating with Tc, the carrier concentration or the Cu-O distance The answer seems to be both. Application of pressure for a fixed composition causes an increase in... 

Vapour pressure systems are tempered in that a properly designed pressure relief system can remove latent heat at a sufficient rate to hold the temperature approximately constant at constant pressure (see Figure 3.3). (The temperature may actually rise or fall slightly at constant pressure due to changes in the liquid composition caused by the reaction and by preferential vaporisation of the more... 

However, as reservoir pressure decreases below the bubble point, the liquid changes composition. The gas that evolves takes the smaller molecules from the liquid, leaving the remaining reservoir liquid with relatively more molecules with large complex shapes. This changing liquid composition causes large increases in viscosity of the oil in the reservoir as pressure decreases below the bubble point. 

Table 4. Scaling exponents from the scaling law D cc 4>" for PNIPAAm gels of various compositions caused to swell and shrink over a series of temperature intervals, as shown in Fig. 11 [121]...

Heat transfer to a system in which there are no phase transitions, no chemical reactions, and no changes in composition causes the temperature of the system to change. Our object here is to develop relations between the quantity of heat transferred and the resulting temperature change. 

Some carbides exist over a composition range owing to vacancies in the C sublattice. Preoccupation with stoichiometric compositions cause measured properties to be assigned to this composition when the material is deficient in carbon. Further, vacancies in the deficient material can order, thereby causing subtle changes in crystal structure and properties. This is frequently overlooked. 

SAFETY PROFILE Variable toxicity depending upon composition. Cause local irritation of eyes, nose, throat, and lungs. Some may lead to chronic bronchitis, emphysema, and bronchial asthma. Dermatitis may result from short contact. Asthma, angioneurotic edema, hives, etc., may result from short periods of inhalation. A topic eczema, angioneurotic edema, hives, etc., may also result from prolonged contact. A common air contaminant. Nuisance aerosols do evoke some tissue response in the lung upon inhalation of sufficient amounts. However, this reaction is potentially reversible and leaves no scar tissue. 

In sediments and the maflc portion of the subducted crust, all of the reactions involving hydrous phases and carbonates involve solid solutions whose compositions depend on the bulk composition, in addition to pressure and temperature. Different bulk compositions cause different phase compositions and thus cause reactions to shift in P-T space, i.e., to start shallower or deeper. In peridotites, amphibole and to some extent chlorite are controlled by continuous and discontinuous reactions however, the other volumetrically important hydrous phases (e.g., brucite, serpentine, talc, and phase A ) in altered harzburgites display a relatively restricted compositional range, at least compared to those present in mafic eclogites. As a result, breakdown reactions of hydrous phases in harzburgites are dominated (in a first approximation) by discontinuous reactions, and take place over a restricted depth range of only a few kilometers. 

This paper will analyse these variations in , and A with a view to rationalising the observations and then examine the A values to determine if they may be used to characterise the damage process via a damage factor and a bridging stress. Such parameters are additional items of information which may be deduced from the usual test which may prove useful in understanding damage in composites caused by interlaminar crack growth. 

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