SERVICE PROPERTIES

The Standard covers bar, plates, sheets, strip, structural shapes rolled stock, pipes, sheets with laminar coating and strip of carbon, alloyed and electrical steels and sets up nondestructive magnetic method of mechanical and service properties and microstructure control. 

In evaluating the economics of a filler it is important to consider the volume of filler that can be added bringing the processing and service properties below that which can be tolerated. Thus in some cases it may be more economical to use a filler with a higher volume cost because more can be incorporated. To judge the economics of a filler simply on its price per unit weight is of little merit. 

In addition, service properties such as abrasion resistance are of interest. 

The acid number is a measure of the acidity of a product and is used as a guide in the quality control of resid or asphalt properties. Since a variety of oxidation products contribute to the acid number, and the organic acids vary widely in service properties, so the test is not sufficiently accurate to predict the precise behavior of asphalt in service. 

In keeping with the general theme of this book, our task is somewhat more difficult inasmuch as we routinely must deal with the effects of water on systems. The tests described in ASTM 3527D are designed to describe the qualities of hydrophobic materials. More often than not, the products that are the subjects of this book will be in moist environments. In many cases, the products will be immersed in water. While the dry tests provide some guidance, it is clear that tensile, compressive, and water flow-through tests are needed to determine and describe the in-service properties of the materials. 

The scope of compounding includes specifying the type and amount of various ingredients in a mix, evolving the mixing procedure and vulcanization methods and their details accordingly. This basically covers the consideration of the requirements of the end use and the service properties of the products, processibility of the compounds and cost. The three most important factors to be considered in the development of a compound are ... 

Many service properties of the products of cross-linking of reactive oligomers are essentially controlled by their distribution in functionality types (Entelis et al., 1989). This important statistical characteristic of... 

EFFECT OF HYDRODYNAMIC STIRRING IN A REACTOR ON SOME SERVICE PROPERTIES OF POLYMER PRODUCTS... 

Some interesting results have been obtained by Russian scientists [320, 321] who studied the influence of composition inhomogeneity on some service properties and supermolecular structures of copolymers. Two samples of copolymers of butyl acrylate with methacrylic acid were synthesized which had a similar average... 

This work aims to produce mixed calcium carboxylate stabilisers for use in place of calcium stearate for the stabilisation of PVC. The new stabilisers are based on mixed salts of stearic acid with derivatives of phthalic or maleic acid and also with branched alpha, alpha-branched carboxylic (C12-C16) acids, noted for their lower cost and adequate effectiveness. Test results are examined in detail for the performance of these stabilisers in terms of service properties, processability, and stabilising action. 2 refs. (Translated from Plasticheskie Massy, No.5, 2000, p.19)... 

The materials BG-M50 and BG-M80 have technological properties enabling their processing to be achieved by the method of pressure casting, as weU as improved service properties. What has been said can be illustrated by the data describing the properties of these materials, as follows ... 

Organic matrices are divided into thermosets and thermoplastics. The main thermoset matrices are polyesters, epoxies, phenolics, and polyimides, polyesters being the most widely used in commercial applications (3,4). Epoxy and polyimide resins are applied in advanced composites for structural aerospace applications (1,5). Thermoplastics Uke polyolefins, nylons, and polyesters are reinforced with short fibers (3). They are known as traditional polymeric matrices. Advanced thermoplastic polymeric matrices like poly(ether ketones) and polysulfones have a higher service temperature than the traditional ones (1,6). They have service properties similar to those of thermoset matrices and are reinforced with continuous fibers. Of course, composites reinforced with discontinuous fibers have weaker mechanical properties than those with continuous fibers. Elastomers are generally reinforced by the addition of carbon black or silica. Although they are reinforced polymers, traditionally they are studied separately due to their singular properties (see Chap. 3). 

A suitable refractory can be selected for a given purpose on the basis of information published in the literature and in manufacturers catalogues. On the other hand, there are certain rules which may be employed in a critical analysis of requirements for the properties and thus facilitate selection of the optimum material or improvement of its service properties. The following main criteria should be considered ... 

V.V. Grigo ev, Influence of Molecular Structure on Physicochemical and Service Properties of Synthetic Oils, Chem. Tech. Puels Oil, 35(2), 94—97, Mar.-Apr. (1999). 

The efficiency of fine filtration affects the surface finish after mechanical processing of semifinished products (sheets, forgings etc.) and such service properties as fatigue endurance. For example, the use of the UZFIRALS process... 

A service property Within a transaction, a system has to react on certain previous inputs within a reasonable number of rounds, whereas at other times, it may be idle and wait for new inputs. 

This section defines both the minimal service that is common to all signature schemes and special service properties that can be used to classify signature schemes. Section 5.2.1 discusses what kind of specification is used and why. Section 5.2.2 gives a brief informal overview of the actual service specification. Sections 5.2.3 to 5.2.7 contain details about the minimal service and about formalization in general. Additional service properties are considered in Sections 5.2.8 to 5.2.12. 

In principle, one can define an arbitrary number of additional service properties. In... 

The general definition should contain few transactions, because any transaction included here has to be offered by all schemes, i.e., they have to react on the corresponding input events in a way prescribed by the minimal requirements. Adding more transactions as special service properties is discussed in Section 5.2.11. 

In the following, strong preconditions are made, and stronger requirements with weaker preconditions are additional service properties (see Section 5.2.8, User-Friendliness ). It should not be hard to devise general constructions that transform schemes fulfilling the minimal requirements into schemes fulfilling stronger, safer requirements. 

The first type of additional service properties is that some signature schemes fulfil stronger versions of the requirements on the results of the three common transactions, in particular disputes. 

As shown in Figure 6.1, all these schemes are with non-interactive authentication, i.e., the notion of a signature exists, and without invisibility. Additional service properties they have in common are ... 

The second service property in which existing fail-stop signature schemes differ is the dependence of authentication on the recipients (see Section 5.2.10). This classification is independent of that according to risk bearers. However, the cases... 

Before the requirements that remain from Section 7.1.3 are formalized, the additional service properties that standard fail-stop signature schemes should have according to Section 6.1.2 are considered. It turns out that most of these requirements are automatically fulfilled according to the assumed structure of the entities around the algorithms from Definition 7.1 or 7.2, respectively. The only remaining one, the strong requirement of the signer on disputes in the case with special risk bearers, can be fulfilled by similar structural measures. 

The choice of a service that meets the needs of the caller is performed by a component called service trader. This is a variation of a name server, where searching for services is done in terms of service type (the kind of service) and non-functional service properties. The CORBA specification includes a standard trading service, which has, in our view, a major drawback (e.g., for multimedia applications) It only performs a hard match (yes/no) of the service parameters onto the request parameters, and does not allow for selection of services that do not exactly fulfill the requirements but have almost the desired properties. 

Our approach [265, 440, 445] enhances the simple selection mechanism of the CORBA trader to consider QoS. Here, an importer (which is the client using a trader to search for a service) describes a service by service tjrpe and service properties as before, but it is possible to specify roles for several values of the same property, namely a target value for the property, a lower bound (minimum acceptable quality) and an upper bound (maximum useful quality). This enhancement allows a client to formulate wishes and limits on service properties, see Fig. 4.16. Additionally, preferences for specifying the importance of properties can be expressed. These values, describing different aspects for the same quality criterion, are called Service Request Property. The importer can specify a whole vector of such properties to express its complete requirements on a service through different QoS aspects. In a similar way, a server offering a service can describe its limitations and capabilities by expressing upper and lower bounds for the quality aspects it can deliver. 

Trading is a valuable concept to support binding between clients and servers in large open systems. Still, individual servers can be overloaded. To avoid such an overload, load balancing can be used. A load balancer tries to realize a perfect distribution of the clients requests to the available servers. Yet, it can only select one server in a particular group in large open systems, the load balancer would have to know exactly the type of the service to select a server. Additionally, the load balancer can only select a server based on its load, not on its service properties. 

Thus, a combination of trader and load balancer seems to be a suitable solution for a load-oriented assignment of servers to clients in a distributed environment [439, 441, 442]. A simple approach would be the usage of load values as dynamic service properties within the trader. The trader could perform a load distribution based on these attributes. Yet, it could be hard or even impossible for a service provider to offer an additional interface where the trader could request the information about dynamic attributes, especially in cases where legacy applications are used. Furthermore, this concept is inflexible, as a more differentiated interpretation of the load value would be hard. Therefore, this simple solution is not feasible in our environment. 

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