Factors affecting properties

Cement properties are affected by a number of factors. Some are determined by the manufacturer, for example the chemical composition of the cement components. Others are under the clinician s control. These include the powder/liquid ratio of the cement mix and the temperature of the surgery. Increase in either of these variables accelerates the reaction and affects properties. 

The powder/liquid ratio used in the cement mix affects a number of properties. As it is increased, setting time and working time are reduced. Compressive strength increases almost linearly with powder/liquid ratio (Savignac, Fairhurst Ryge, 1965). 

Film thickness is controlled by a number of factors. The grain size of the powder imposes a lower limit on its value and rheological characteristics of the cement affect flow (Jorgensen Peterson, 1963). An increase in the powder/liquid ratio or a delay in seating a restoration leads to an increase in film thickness. The geometry of the surfaces to be cemented also affects flow and hence film thickness (Windeler, 1979). 

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Factors Affecting Properties of Biodegradable Polymer Blends... 

C. Barbie, C. Angibaud, T. Damls, F. Lefebvre, M. Rabaud, M. Aprahamian, Some factors affecting properties of elastin-fibrin biomaterial. Biomaterials 10(7), 445-448 (1989)... 

H. Honma, K. Hagihara, and K. Kobayashi, Factors Affecting Properties of Electrolessly Deposited Copper, Circuit Technology (Japanese), Vol. 9, No. 1,1994, pp. 31-36. 

Conformational analysis is the study of how conformational factors affect the structure of a molecule and its physical chemical and biological properties... 

Many factors affect the mechanisms and kinetics of sorption and transport processes. For instance, differences in the chemical stmcture and properties, ie, ionizahility, solubiUty in water, vapor pressure, and polarity, between pesticides affect their behavior in the environment through effects on sorption and transport processes. Differences in soil properties, ie, pH and percentage of organic carbon and clay contents, and soil conditions, ie, moisture content and landscape position climatic conditions, ie, temperature, precipitation, and radiation and cultural practices, ie, crop and tillage, can all modify the behavior of the pesticide in soils. Persistence of a pesticide in soil is a consequence of a complex interaction of processes. Because the persistence of a pesticide can govern its availabiUty and efficacy for pest control, as weU as its potential for adverse environmental impacts, knowledge of the basic processes is necessary if the benefits of the pesticide ate to be maximized. 

To predict the comfort of a material, a combination of hand evaluation, eg, using the Kawabata system, as well as deterrnination of the heat and moisture transport properties, is necessary. Often, these values are correlated with a sensory evaluation of the tactile qualities of the material by a human subject panel. A thorough discussion of the many physical and psychological factors affecting comfort is available (134,135). 

Another important factor affecting the electronic properties is the steric barrier to planarity along the polymer chain. Since polyheterocycles and polyarylenes must adopt a planar geometry in the ionized state to form quinoid-like segments, steric factors that limit the ability of the polymer to adopt geometries which are planar with respect to adjacent rings have a detrimental effect on the electronic properties (181). 

The most important factors affecting performance are operating temperature, surface velocity, contaminant concentration and composition, catalyst properties, and the presence or absence of poisons or inhibitors. 

The properties of a given polymer will very much depend on the way in which crystallisation has taken place. A polymer mass with relatively few large spherulitic structures will be very different in its properties to a polymer with far more, but smaller, spherulites. It is thus useful to consider the factors affecting the formation of the initial nuclei for crystallisation (nucleation) and on those which affect growth. 

One of the most important conclusions from this is that since both the viscous and the high elastic components of deformation depend on both time and temperature, the total deformation will depend on time and temperature. Since this fact has been shown to be an important factor affecting many polymer properties it is proposed to consider the background to this in greater detail in the following section. 

Many properties have an influence on nucleophilicity. Those considered to be most significant are (1) the solvation energy of the nucleophile (2) the strength of the bond being formed to carbon (3) the size of the nucleophile (4) flie electronegativity of the attacking atom and (5) the polarizability of the attacking atom. Let us consider how each of these factors affects nucleophilicity ... 

Numerous factors affect the spread of luizardous substances into tlie area surrounding a leaking/buming container or contaituuent vessel. Evacuation decision-makers must carefully consider each of tliese factors in order to determine the conditions created by the release, tlie areas tluit have been or will be affected, and the heiilth affects on people. The factors tliat affect evacuation include amount of released material(s), physical and cheniical properties of the released material(s), health hazards, dispersion pattern, rate of release, and potential duration of release. Each of these factors is explained below. 

Fig. 6-8. Factors affecting the recognition properties of MIPs related to the monomer template assemblies.

Apart from the successful imprinting discussed above, the recognition for many templates is far from that is required for the particular application, even after careful optimization of the other factors affecting the molecular recognition properties. Often, a large excess of MAA in the synthesis step is required for recognition to be observed and then only in solvents of low to medium polarity and hydrogen bond... 

One of the important factors affecting composite properties is the amount of fiber it contains, i,e., percentage by volume. 

For a hot water environment general guidance can be given for the desirable properties in good enamels. Five factors affecting enamel life are corrosiveness of contact liquor, design, operating conditions, life of sacrificial anode (if any) and the durability of the enamel coat. This implies that... 

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