Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Importance of Temperature Control

Process efficiency (primary and secondary drying times) is directly related to these main operating parameters. It must be borne in mind that too high processing temperatures will compromise several important quality factors (therapeutic or biological activity, mechanical structure resistance, porosity, appearance, crack formation, etc.). [Pg.79]


Attention is directed to the importance of temperature control in conductance measurements. While the use of a thermostat is not essential in conductimetric titrations, constancy of temperature is required but it is usually only necessary to place the conductivity cell in a large vessel of water at the laboratory temperature. [Pg.523]

The importance of temperature-controlled scanning calorimetry for measurements of heat capacity and of scanning transitiometry for simultaneous caloric and pVT analysis has been demonstrated for polymorphic systems [9]. This approach was used to study an enantiotropic system characterized by multiphase (and hindered) transitions, the role of heat capacity as a means to understand homogeneous nucleation, and the creation of (p, T) phase diagrams. The methodology was shown to possess distinct advantages over the more commonly used combination of characterization techniques. [Pg.265]

The importance of temperature control of the GPC column cannot be overstated. The use of temperatures above ambient results in lower mobile-phase viscosity, which in turn reduces the back pressure generated by the column. Column life is prolonged, and in some cases higher flow rates may be employed. The reduction in mobile-phase viscosity improves both the rate and efficiency of mass transfer processes, enhancing column performance. While... [Pg.202]

The stability of both the racemate and isolated enantiomer was re-investigated, and although the materials were stable at ambient temperature, at >40 °C care would be required as epimerizahon could occur. This finding highlighted the importance of temperature control and monitoring during the isolation, but also indicated that it might be possible to introduce a simple procedure to effect racemization of the unwanted enantiomer. [Pg.210]

The importance of temperature control is significant for laboratory comparisons, accelerated shelf-life studies, and packaging requirements. Also, temperature may be essential when measuring aw levels near critical values, especially for government regulations or critical control points. The precision required in water activity applications will determine the need for temperature control. Several reasons for sample temperature control are ... [Pg.47]

III. The Freeze-Drying Process The Importance of Temperature Control... [Pg.395]

The importance of temperature control is illustrated by considering a sample with an activation energy of leV for the conductivity at 800°C a change of 1°C would produce a change of 1% in conductivity. At 300°C, the same error would produce a change of 3.5%. A temperature stability of 1°C or better can be easily achieved with present-day three-term controllers, but this alone is not sufQcient to ensure good temperature control temperature gradients in the rig must be kept to a minimum and the temperature sensor must be in thermal contact with the sample. [Pg.231]

In addition to maintaining the circulation of the reaction Hquid, the inert gas is important in temperature control, and it prevents the formation of a separate nonaqueous phase by carrying off substantial quantities of dichloropropane in the effluent. [Pg.74]

IMBALANCED BODY TEMPERATURE If the patient is receiving the analgesic for reduction of elevated body temperature the nurse checks the temperature immediately before and 45 to 60 minutes after administration of the drug. If a suppository fonn of the drug is used, it is important to check the patient after 30 minutes for retention of the suppository. If the drug fails to lower an elevated temperature, the nurse notifies the primary health care provider because other means of temperature control, such as a cooling blanket, may be necessary. [Pg.155]

A more detailed picture of the temperature dependence of the growth is given in Figure 2.4, where the island density is plotted as a function of temperature. It can be seen that only in the temperature range from 207 to 288 K the growth is perfectly template controlled and the number of islands matches the number of available nucleation sites. This illustrates the importance of kinetic control for the creation of ordered model catalysts by a template-controlled process. Obviously, there has to be a subtle balance between the adatom mobility on the surface and the density of template sites (traps) to allow a template-controlled growth. We will show more examples of this phenomenon below. [Pg.33]

The idea that certain physical states could reproduce always the same temperature rises in the second half of seventeenth century (Hooke, 1664 Renaldini, 1694, see e.g. ref. [8]). Intuitions of this idea can be also found in Aristotele and Galeno. Nowadays, the importance of the control of the thermometric calibration is underestimated and the use of reference fixed points is usually limited to metrological laboratories. [Pg.193]

The accuracy of temperature controllers and sensors is typically about 0.1°. Because of their high-thermal mass, packed columns are more often operated isothermally, while due to their low-thermal mass, capillary columns are most often temperature programed. Important parameters related to basic column dimensions are shown in Table 14.4. [Pg.465]

The importance of temperature measurement can even be seen simplistically by consideration of the financial aspects of the sensors and devices used worldwide. Estimates on the worldwide sales oftemperature sensors run to several hundred million dollars per year,(1) a figure that could be increased several times when the associated controllers, indicators, and other aspects of the measurement system are added. [Pg.335]

Safety assessment scientists and technicians and even QA personnel sometimes overlook the importance of environmental control equipment to valid study results. Animals stressed by extremes of temperature or humidity may 5ueld spurious data reproductive toxicology studies may be compromised by malfunctioning timers for the control of light/ dark cycles inadequate air filtration may expose experimental animals to environmental contaminants that confound experimental results. [Pg.73]

When one considers the effect of variation of temperature during a test there are two distinct cases. First in long term tests such as creep it is important that the temperature control is very good ( 0.1°) naturally the precision of temperature control becomes more important close to relaxation temperature. Secondly in short term tests we must decide whether the experiment is conducted isothermally, or adiabatically. The moduli will of course be different in the two cases. [Pg.94]

In this chapter we take the steady-state designs of a variety of CSTR systems discussed in Chapter 2 and study their dynamics and control. The effects of reaction types, kinetics, design parameters, and heat removal schemes on controllability will be quantitatively explored. The important effects of design conversion and heat transfer area on the effectiveness of temperature control will be demonstrated. [Pg.107]

Some polymerization reactions are highly exothermic, so the problems of temperature control, which are the major emphasis of this book, are important in these systems. However, beyond the issue of temperature control, polymer reactors must produce a product with the desired properties. The final polymer product properties, such as viscosity, molecular weight distribution, particle size, and composition, are important for consistent performance of the polymer. These properties depend on more than just temperature and few can be measured online.12... [Pg.414]

Temperature is an important and often ignored parameter in method optimization. A lack of temperature control can result in poor inter- and intralaboratory reproducibility. Increased temperatures can speed up and alter separations and may improve efficiency and throughput, especially of macromolecules. High-temperature work using superheated water can eliminate organic solvents from the mobile phase, simplifying detection and solvent interferences in detection. At lower temperature the reduction in molecular motion can resolve interconverting chiral and structural analytes. [Pg.830]

The Gibbs phase rule is very useful in predicting the importance of the control variables in a chemical reaction system. These variables include pressure, temperature and composition, as well as the effect on phase equilibrium. It can also be used to predict which way a given reaction will progress when the controlled variables are changed. [Pg.134]


See other pages where Importance of Temperature Control is mentioned: [Pg.470]    [Pg.375]    [Pg.422]    [Pg.229]    [Pg.2]    [Pg.113]    [Pg.112]    [Pg.78]    [Pg.95]    [Pg.116]    [Pg.470]    [Pg.375]    [Pg.422]    [Pg.229]    [Pg.2]    [Pg.113]    [Pg.112]    [Pg.78]    [Pg.95]    [Pg.116]    [Pg.494]    [Pg.126]    [Pg.193]    [Pg.185]    [Pg.68]    [Pg.536]    [Pg.92]    [Pg.100]    [Pg.130]    [Pg.164]    [Pg.420]    [Pg.79]    [Pg.2414]    [Pg.2433]    [Pg.414]    [Pg.45]   


SEARCH



Import controls

Temperature control

Temperature control controllers

Temperature controller

Temperature-controlled

© 2024 chempedia.info