Physical property tests density measurements

Physical-property tests are used to measure the properties of adhesives in the liquid or gelled states prior to curing and in the solid state after curing. Tests for the uncured state such as viscosity, visual examination, and surface energy or contact angle assure that fillers, if used, have not settled out, that the material has not exceeded its pot life or shelf life, and that the supplier has not changed the formulation. Visual examination and density after cure are performed to verify that voids are not present or, if present, meet specification requirements. Finally, light transmission and index of refraction measurements are important for adhesives used in optoelectronic applications. 

Findings with PDU. Work with the PDU largely paralleled the bench-scale reactor tests there was one important addition—extensive three-phase fluidization studies. As was mentioned, the PDU is equipped with a traversing gamma-ray density detector that is capable of measuring bed density to within dbO.Ol specific gravity units. Thus, we could measure and correlate fluidized bed expansion as a function of liquid and gas velocities and physical properties, and could also determine the... 

The physical properties important for the projected use of hydraulic fluids are viscosity, density, foaming behavior, and fire resistance. There is no generally recognized test method for measuring flammability of hydraulic fluids, although various test methods maybe utilized (Moller 1989). 

Density, viscosity and elasticity of the foam lamellae, as essential physical properties of the foam, cannot be measured. They all depend on the physical properties of the investigated multiphase material system, including the type and concentration of surfactants. These properties can usually not be measured, particularly not if they are produced in situ by the bacterial culture. We will therefore introduce into the relevance list the sum of all physical properties, Si which affect the destructibility of the foam as well as the concentration, cT (e.g. in [ppm]), ofa known tenside used in the tests. 

There are other properties besides density and solubility that can be measured precisely and expressied in terms of numbers. Such another property is the melting point, the temperature at which a crystalline substance melts to form a liquid. The electrical conductivity and the thermal conductivity are similar properties. On the other hand, there are also interesting physical properties of a substance that are not so simple in nature. One such property is the malleability of a substaqce—the ease with which the substance can be hammered out into thin sheets. A related property is the ductility—the ease with which the substance can be drawn into a wire. Hardness is a similar property we say that one substance is less hard than a second substance when it is scratched by the second substance, but this test provides only qualitative information about the hardness. A discussion of hardness is piesented in Chapter 6. 

Test methods of interest for hydrocarbon analysis of residual fuel oil include tests that measure physical properties such as elemental analysis, density, refractive index, molecular weight, and boiling range. There may also be some emphasis on methods that are used to measure chemical composition and structural analysis, but these methods may not be as definitive as they are for other petroleum products. 

General aspects of petroleum quality (as a refinery feedstock) are assessed by measurement of physical properties such as relative density (specific gravity), refractive index, or viscosity, or by empirical tests such as pour point or oxidation stability that are intended to relate to behavior in service. In some cases the evaluation may include tests in mechanical rigs and engines either in the laboratory or under actual operating conditions. 

Analysis performed in the field is faster and more economical than analysis done in a laboratory. As analytical techniques are constantly improving and lighter and more portable equipment is being developed, more analytical work can be carried out directly in the field. Test methods are now available for measuring physical properties of oil such as viscosity, density, and even flash point in the field. Test kits have also been developed that can measure total petroleum hydrocarbons directly in the field. While these test kits are less accurate than laboratory methods, they are a rapid screening tool that minimizes laboratory analysis and may provide adequate data for making response decisions. 

Quantitative and (hopefully, at least) qualitative considerations are helpful in characterizing a liquid-liquid system for a potential extraction application. Batch shakeout tests are frequently the easiest way to determine basic feasibility by simply measuring the primary and secondary break times and by analyses to measure the compositions of the equilibrated phases. Such tests are readily conducted by mixing small volumes of each phase in a vial, which is then vigorously agitated and placed on a lab bench to settle. The resulting behavior of the liquid-liquid mixture depends on physical properties and system characteristics. The greater the density difference and interfacial tension between the two liquid phases, for example, the more rapidly the phases tend to separate. More viscous systems separate more slowly. 

Elemental Analysis and Physical Properties. Elemental analysis was accomplished by conventional microanalytical techniques in a commercial testing laboratory. Densities were measured on a Mettler/Paar digital density meter, model D.M. 40. Number average molecular weights were determined by VPO in benzene. Simulated distillation was accomplished using a 1/4" by 18" column of 3% dexsil 300 on chromosorb W, programmed from -30° to 350°C at 10°/minute with a 4 minute hold at 350°C. The detector was a flame ionization detector maintained at 400°C. 

The laboratory evaluations of cracking catalysts may be divided into essentially two categories (1) testing of activity for the conversion of a standard gas-oil to gasoline, gas, and coke, and (2) measurement of physical properties such as particle size, density, surface area, and pore-size distribution. 

A number of physical measurements on cracking catalysts are employed to complement the direct activity tests. Ries (26) has reviewed the principal methods employed in determining the physical properties of porous solids, and no attempt will be made to do so again in detail here. The determinations of surface area, bulk density, particle density, and real density are practically routine procedures in studying all types of cracking catalysts. From these data, the pore volume of catalyst particles, intergranular free volume, and average pore diameter can be calculated (Emmett and DeWitt, 27). 

Plate efficiencies and HETP values are complex functions of measurable physical properties temperature, pressure, composition, density, viscosity, diflusivity, and surface tension measurable hydrodynamic factors pressure drop and liquid and vapor flow rates plus factors that cannot be predicted or measured accurately foaming tendency, liquid and gas turbulence, bubble and droplet sizes, flow oscillations, emulsification, contact time, froth formation, and others. Values for plate efficiency, HETP, or HTU, particularly those that purport to compare various devices, are usually taken over a limited range of concentration and liquid-to-vapor ratios. The crossovers in Fig. 2.5 and the rather strange behavior of the ethyl alcohol-water system, Fig. 2.6, demonstrate the critical need for test data under expected operating conditions. ... 

Some polymers can be used to produce foam possessing a wide range of properties. For example, polyurethane can be made hard or soft, flexible or rigid, at high or low densities. Polyurethane has an exceptional range of physical property variation and provides an unprecedented example to which many of the other cellular polymer test methods can be compared. Indeed, many of the methods used for the polyurethane family of polymers are eommon to the other polymeric foams. This subject is extensive, and a chapter such as this cannot hope to be exhaustive. However, it is hoped that most major physical property measurements are covered or at least guidance given to the reader as to where details can be obtained. 

In the past, quality control of perfumes was done by measuring physical properties like the refractive index, density, and optical rotation, in addition to very simple chemical tests like acidimetry and measurement of the saponification and carbonyl indexes. However, these tests were only useful for checking the raw materials or the final product, and they did not offer an actual determination of the compounds that were present in an unknown perfume. 

Here, the sample is subjected to a sinusoidal oscillating mechanical deformation, in the rheometer s preheated test chamber, which is opposed by a mechanical resistance, measured as torque. The time for 90% or 95% increase in torque for a rheograph is regarded as the optimum cure time. The rise in torque is considered to be proportional to increase in crosslink density and the crosslink density determines the physical properties of the compounded rubber. 

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