Property types measured

It is also possible to simulate nonequilibrium systems. For example, a bulk liquid can be simulated with periodic boundary conditions that have shifting boundaries. This results in simulating a flowing liquid with laminar flow. This makes it possible to compute properties not measurable in a static fluid, such as the viscosity. Nonequilibrium simulations give rise to additional technical difficulties. Readers of this book are advised to leave nonequilibrium simulations to researchers specializing in this type of work. 

In this chapter we define what is meant by a shock-wave equation of state, and how it is related to other types of equations of state. We also discuss the properties of shock-compressed matter on a microscopic scale, as well as discuss how shock-wave properties are measured. Shock data for standard materials are presented. The effects of phase changes are discussed, the measurements of shock temperatures, and sound velocities of shock materials are also described. We also describe the application of shock-compression data for porous media. 

Measurements of particle porosity are a valuable supplement to studies of specific surface area, and such data are particularly useful in the evaluation of materials used in direct compression processes. For example, both micromeritic properties were measured for several different types of cellulosic-type excipients [53]. Surface areas by the B.E.T. method were used to evaluate all types of pore structures, while the method of mercury intrusion porosimetry used could not detect pores smaller than 10 nm. The data permitted a ready differentiation between the intraparticle pore structure of microcrystalline and agglomerated cellulose powders. 

It is also essential to have a clear understanding of the analyte or property being measured. For example, an analyst may be studying the amount of lead present in paint used on toys. One possibility would be to use a method which determines the total amount of lead present. Alternatively, the analyst may be interested in the amount of lead that is released from a paint sample taken from a toy when it has been extracted with a stomach-acid simulant. In both cases, the end measurement is the same - the concentration of lead in a solution. However, the results from the two approaches would be very different. In the first case, the sample will have been digested with a strong acid solution which should release all of the lead present in the sample. In the second case, we would expect the results to be lower as the method is designed to estimate the amount of lead released under particular conditions. The second type of method is sometimes referred to as an empirical method. This is a method where the result produced is entirely dependent on the analytical method. In the above example, if the... 

A common laboratory device is a batch reactor, a nonflow type of reactor. As such, it is a closed vessel, and may be rigid (i.e., of constant volume) as well. Sample-taking or continuous monitoring may be used an alternative to the former is to divide the reacting system into several portions (aliquots), and then to analyze the aliquots at different times. Regardless of which of these sampling methods is used, the rate is determined indirectly from the property measured as a function of time. In Chapter 3, various ways of converting these direct measurements of a property into measures of rate are discussed in connection with the development of the rate law. 

The number and type of test pieces exposed for each measurement point will depend on the property being measured. If measurement is non-destructive, e.g., loss of mass or colour, then the same specimens can be used throughout the test, being replaced in the oven after each measurement. If the measurement is destructive then one set of specimens must be prepared for each combination of duration and temperature. It is recommended to expose at least two reserve sets in case the threshold level has not been reached by the end of the last planned duration. Usually the number specified in the relevant test method standard is chosen but, again, the more the better. An example and some of the problems are described in Section 12.2. 

In many systems, there may be just a few variables which have a large effect on the property being measured. If we can make this assumption, we may be able to select these variables from a number of others by a relatively small number of experiments. A design of the type shown can be used in which two levels, a high and low level, of each factor can be selected, In the design, 0 represents the low level and 1 the high level of each factor... 

Several European intensive short-term ( campaign-type ) projects have provided important information on the atmospheric aerosol properties in Europe, usually by concentrating on specific aerosol properties or interactions. However, these kinds of campaign-type measurements do not necessarily represent the seasonal or annual variations of the aerosol concentrations and can overestimate some properties of the aerosol populations. Long-term measurements, especially with intercalibrated instruments and common data handling and calibration protocols make the data comparison between stations much more reliable and provide the end users (e.g., atmospheric modelers) good datasets to compare with. 

To further explore the influence of silica material properties (morphology, surface area, silanol concentration, and surface treatment) on the silica flame-retardant properties, various types of silicas (silica gel, fumed silicas, and fused silica) were investigated.50 51 Material properties of the various silicas are summarized in Table 8.6. These different types of silicas were added to polypropylene and polyethylene oxide to determine their flame-retardant effectiveness and mechanisms. Polypropylene was chosen as a non-char-forming thermoplastic, and polyethylene oxide was chosen as a polar slightly char-forming thermoplastic. Flammability properties were measured in the cone calorimeter and the mass loss rate was measured in the radiative gasification device in nitrogen to exclude any gas phase oxidation reactions. 

Different materials expand at different rates when heated. Different types of the same materials can have different rates of expansion as well. Thus, different types of glass have radically different expansion properties. The measure of the rate of expansion of materials is the thermal coefficient of expansion stated in Acm/cm/ °C. Because the thermal coefficient of expansion of any material varies as the temperature varies, the thermal coefficient of expansion that is attributed to any particular glass is based on an average of the expansion figures compiled from a 0-300°C range. Table 1.2 includes the thermal coefficients of expansion for a variety of glasses. 

Solute property detectors measure a characteristic of the solute alone. These detectors are generally more sensitive yielding a detectable signal for nanogram quantities of solute. Representative detectors of this type include, for example, ultra-violet (UV), solute transport, fluorescence, and conductivity monitors. Other less frequently employed detectors of this nature are those based on radioactivity, polarography, and... 

In some situations where one or more of the latex properties are measured either directly or indirectly through their correlation with surrogate variables and where extreme nonlinearities such as the periodic generation of polymer particles does not occur, one can use much simpler modehng and control techniques. Linear transfer function-type models can he identified directly from the plant reactor data. Conventional control devices such as PID controllers or PID controllers with dead-time compensation can then be designed. If process data is also used to identify... 

We have investigated the recovered glassfiber-resin powder for its properties as a filler for epoxy resin compounds which are used as paints or adhesives, and compared it to conventional fillers, such as talc and calcium carbonate. The epoxy resin compound, composed of bisphenol A type epoxy resin (50.0wt%), aliphatic polyamine type hardener (18.0wt%) and filler (32.0%), was prepared. Strength and thermal expansion properties were measured for the molded epoxy resin compound cured 23°C for 7 days. Viscosity was measured for the epoxy resin compound before adding the hardener. Adhesive strength was measured by tearing two ferric boards bonded with the epoxy resin compound which was composed of bisphenol A type epoxy resin (49.2wt%), polyaminoamide type hardener (18.0wt %), and filler (32.8wt%), and was cured at 23°C for 7 days. 

The slope of the first part of the stress-strain curve is a measure of the flexibility of a board. Numerous attempts have been made to measure this property by measuring load versus deflection on the constant stress type of tester, but it is not practical on this type of machine. The area under the curve measures the total work required to break the board or the toughness of the board. 

Summary In concluding the treatment of physical properties of catalysts, let us review the purpose for studying properties and structure of porous solids. Heterogeneous reactions with solid catalysts occur on parts of the surface active for chemisorption. The number of these active sites and the rate of reaction is, in general, proportional to the extent of the surface. Hence it is necessary to know the surface area. This is evaluated by low-temperature-adsorption experiments in the pressure range where a mono-molecular layer of gas (usually nitrogen) is physically adsorbed on the catalyst surface. The effectiveness of the interior surface of a particle (and essentially all of the surface is in the interior) depends on the volume and size of the void spaces. The pore volume (and porosity) can be obtained by simple pycnometer-type measurements (see Examples 8-4 and 8-5). The average size (pore radius) can be estimated by Eq. (8-26) from the... 

Objects of this class determine what types of properties are available in descriptions of objects of various ArrayExpress classes. Attributes of this class include property name, measurement units, free-text description, list of class names determining which objects can have properties of this type. 

Tensile properties were measured by using Shimadzu mechanical tester DSS5000. The cross head speed was 2 mm/min. Viscoelastic properties(tensile storage modulus and tan S) were measured by a tensile type dynamic mechanical analysis(SEIKO Instrument DMS 200). The... 

CPB Materials. Various types of silane crosslinkers were employed to fabricate crosslinked polymer blend (CPB) dielectrics in this study (Fig. 4). The reactivity of each crosslinker was tested via in situ NMR kinetic studies. The CPB dielectrics were fabricated on various substrates using mixture of polymer and crosslinker solution via spin-coating and gravure-printing. Organic semiconductors and source/ drain electrodes were vacuum-deposited to complete the OFET device. Dielectric and OFET properties were measured under vacuum and ambient as described previously. 

Two general type of detection devices are available. These are bulk property detectors and solute property detectors. The bulk property detector measures a change in some overall physical property in the mobile phase as it emerges from the column. Two typical examples are measurement of refractive index and conductance. The solute property detector is sensitive to changes in a physical property of the solute as it emerges from the column in the mobile phase a typical example is the measurement of ultraviolet and / or visible absorption. In general,... 

Over the last ten years, the STM has given birth to a whole family of scanning proximity probes [6.66]. The nature of the feedback criteria, i.e. the property being measured and used to generate the vertical detail, along with the type of sample being examined, distinguishes which SPM is used. 

A new type of situation arose with the use of carbon for potable water supplies. It was soon recognized that decolorizing properties as measured by the M-RE would be needlessly costly because they have no direct value for removing tastes and odors from water supplies. A search for a test that would reveal the power of a carbon for removing taste and odor resulted in the phenol test. This made it practicable to produce carbons that not only were more effective for control of taste and odor but also could be manufactured at a much lower cost. All of this contributed much to great subsequent expansion in the use of carbon for potable water supplies. 

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