Experimental procedure temperature

ASTM Method 1238, Standard Test Method for Flow Rates of Thermoplastics by Extrusion Plastometer [6], completely defines the melt index, both the instrument and the experimental procedure. Temperatures and instrument configurations for common materials are given along with recommended calibration procedures and round-robin results. This method must be strictly followed if consistent melt index results are to be obtained. A melt index measurement is performed at low stress levels compared to capillary rheometers measurements (typical weights are in the range of 1.2-21.6 kg) and is sensitive to variations in operating procedure, instrument cleanliness (between tests), and operator bias (items such as packing and sample preparation). 

Everett and co-workers [141] describe an improved experimental procedure for obtaining FJ quantities. Some of their data are shown in Fig. XI-10. Note the negative region for n at the lower temperatures. More recent but similar data were obtained by Phillips and Wightman [142]. 

In considering the differential energy of adsorption, it is useful to picture an experimental procedure which allows the adsorption to proceed at constant temperature and in infinitely small stages. Then... 

Following the movement of airborne pollutants requires a natural or artificial tracer (a species specific to the source of the airborne pollutants) that can be experimentally measured at sites distant from the source. Limitations placed on the tracer, therefore, governed the design of the experimental procedure. These limitations included cost, the need to detect small quantities of the tracer, and the absence of the tracer from other natural sources. In addition, aerosols are emitted from high-temperature combustion sources that produce an abundance of very reactive species. The tracer, therefore, had to be both thermally and chemically stable. On the basis of these criteria, rare earth isotopes, such as those of Nd, were selected as tracers. The choice of tracer, in turn, dictated the analytical method (thermal ionization mass spectrometry, or TIMS) for measuring the isotopic abundances of... 

An automated system for clinical analysis consists of the instmment (hardware), the reagents, and the experimental conditions (time, temperature, etc) required for each deterrnination. The reagents plus the experimental conditions are sometimes referred to as the chemistry of the system. The chemistry employed is generally similar to that used in manual assays because most automated assay methods have been adapted from the manual ones. However, automated analy2ers rarely afford the flexibiUty of experimental procedure that is possible in manual analysis. 

In particular we thought it would be useful to include cross-references of functional group transformations and an experimental procedure, so that the reader will be able to evaluate the reaction conditions at a glance for instance is this reaction carried out at room temperature or at 200 C For 1 h or 5 days Are special catalysts required How is the reaction worked up, what yield can be expected ... 

With correct experimental procedure TDS is straightforward to use and has been applied extensively in basic experiments concerned with the nature of reactions between pure gases and clean solid surfaces. Most of these applications have been catalysis-related (i. e. performed on surfaces acting as models for catalysts) and TDS has always been used with other techniques, e.g. UPS, ELS, AES, and LEED. To a certain extent it is quantifiable, in that the area under a desorption peak is proportional to the number of ions of that species desorbed in that temperature range, but measurement of the area is not always easy if several processes overlap. 

As described in Section 6.2.1., British Gas performed full-scale tests with LPG BLEVEs similar to those conducted by BASF. The experimenters measured very low overpressures firom the evaporating liquid, followed by a shock that was probably the so-called second shock, and by the pressure wave from the vapor cloud explosion (see Figure 6.6). The pressure wave firom the vapor cloud explosion probably resulted from experimental procedures involving ignition of the release. The liquid was below the superheat limit temperature at time of burst. 

Experimental Procedure. For the initial start-up of the continuous tirred tank reactor, the mixing speed and bath temperature were adjusted with the reactor full of solvent. The polymer seed and monomer feed rates were then adjusted simultaneously. 

The experimental procedure employed a capillary viscometer made of quartz as shown in Fig. 26. A solid sample was put in the filtration chamber and the top of the chamber was sealed under a vacuum. Then the sample was heated to melting and filtered into the viscometer and the connecting tube sealed at the middle. The viscometer was settled inside a transparent electric furnace and after the temperature of the melt was stabilized, the furnace containing the viscometer was turned upside down, which transferred the melt into the funnel. Then the tube was turned... 

The kinetics of the various reactions have been explored in detail using large-volume chambers that can be used to simulate reactions in the troposphere. They have frequently used hydroxyl radicals formed by photolysis of methyl (or ethyl) nitrite, with the addition of NO to inhibit photolysis of NO2. This would result in the formation of 0( P) atoms, and subsequent reaction with Oj would produce ozone, and hence NO3 radicals from NOj. Nitrate radicals are produced by the thermal decomposition of NjOj, and in experiments with O3, a scavenger for hydroxyl radicals is added. Details of the different experimental procedures for the measurement of absolute and relative rates have been summarized, and attention drawn to the often considerable spread of values for experiments carried out at room temperature (-298 K) (Atkinson 1986). It should be emphasized that in the real troposphere, both the rates—and possibly the products—of transformation will be determined by seasonal differences both in temperature and the intensity of solar radiation. These are determined both by latitude and altitude. 

In order to confirm that the absorption bands appeared at 3668, 2936 and 2870 cm are derived from the reaction of CH4 with the adsorbed peroxide, CD, was used instead of CH,. The IR spectra recorded in the regions of 4000-2000 cm and of 1500-700 cm are show n in Fig. 7. The experimental procedures for the results of Fig. 7 were the same as those for Fig. 6. When the temperature w as increased to 473 K in the presence of CD4, the bands at 895 cm, ascribed to the adsorbed peroxide, decreased remarkably. The new bands at 2692, 2208 and 2124 cm w ere observed simultaneously. Obviously, these are the isotopic bands of those... 

Tyrpical experimental procedures are as follows for DP method, which is used for the industrial production of gold catalysts. To an aqueous solution of H AuCU, the pH of which is 2-3, an aqueous solution of NaOH is added to adjust the pH at a fix point in the range of 6-10. In neutral or weakly basic solution AuClj" ion is transformed into AuCl (OH)4l ( = 4 0). To this solution support materials are immersed or dispersed. When the pH, concentration, and temperature are carefully adjusted, solid Au(OH)3 precipitate is deposited exclusively on the... 

General Experimental Procedures. Charge 1.0 eq. of substrate, 0.005 eq. or less catalyst, 8 volumes of dichloromethane, 8 volume of methanol. Purge the system three times each with nitrogen and hydrogen. Maintain the temperature at 25°C and hydrogen pressure at 45 psig, until the reaction is deemed complete. 

A rational development of models for moisture uptake begins with a description of the experimental procedure used to determine moisture uptake as a function of time. The first step in the experiment is to control the relative humidity to which a sample will be exposed. One technique to control humidity is to use saturated salt solutions. When placed in a closed system and held at a constant temperature, a saturated aqueous salt solution will provide a constant humidity (RH0) within that system. Table 1 lists relative humidities that will be maintained over various saturated salt solutions [14],... 

Experimental Procedure. In a typical liquefaction experiment, the autoclave was charged at room temperature with Tetralin-d12, coal and deuterium gas. In E10, a rocking autoclave was used. In El9, a stirred autoclave was used with a special stirrer which conformed to the shape of the autoclave liner. 

The experimental procedure to carry out the solvent-acceptor reactions have previously been described [2,3]. In summary, the desired amount of solvent was charged to a stirred autoclave and heated to a temperature about 5°C above reaction temperature. The acceptor with additional solvent was injected into the reactor which rapidly came to the desired... 

It is commendable experimental procedure to repeat each run in duplicate and to be satisfied if the two results agree, but this is expensive in terms of the labor costs involved. Moreover, repetition of each run is not always necessary. For example, if one is studying the effect on the reaction rate of a variable such as temperature or reactant concentration, a series of experiments in which the parameter under investigation is systematically varied may be planned. If a plot of the results versus this parameter yields a smooth curve, one generally assumes that the reproducibility of the data is satisfactory. 

The experimental procedure is outlined schematically in Fig. 13 a detailed description was given by Hartog et al. 37). Benzene vapor and deuterium gas, in the molar ratio of 1 18, were passed through a catalyst bed and then through a cold trap immersed in liquid nitrogen in which the hydrocarbons were frozen out. The temperature of the catalyst bed was... 

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