Specify Properties

You use Property Method to tell Aspen Plus what thermodynamic model you want to use. 

Initially all models are available. You can limit the choices by selecting an indushy or 

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Three frequently specified properties are density—specific gravity—API gravity, characterization factor, and sulfur content (2,6,7). The API (American Petroleum Institute) gravity is a measure of density or specific gravity (sp gr) ... 

An area that has used chemical stmctures for predictive purposes quite successfully is the estimation of thermophysical properties of compounds. There has been an extensive compilation of estimation methods (81), and prediction of physical properties has been automated using these techniques (82). More recendy, the use of group contribution techniques to design new molecules that have specified properties has been described (83). This approach to compound design is being used to develop replacement materials for chloroduorocarbons. 

Materia] Selector Access to (1) GE Select, a comprehensive database in Microsoft Windows format of the family of GE polymers which allows users to sort for the GE product families and grades of materials that will best meet the specified property ranges, and (2) CAMPUS, a worldwide database for plastic materials with uniform global protocol for acquiring and comparing data on competitive plastic materials. 

The recovery of petroleum from sandstone and the release of kerogen from oil shale and tar sands both depend strongly on the microstmcture and surface properties of these porous media. The interfacial properties of complex liquid agents—mixtures of polymers and surfactants—are critical to viscosity control in tertiary oil recovery and to the comminution of minerals and coal. The corrosion and wear of mechanical parts are influenced by the composition and stmcture of metal surfaces, as well as by the interaction of lubricants with these surfaces. Microstmcture and surface properties are vitally important to both the performance of electrodes in electrochemical processes and the effectiveness of catalysts. Advances in synthetic chemistry are opening the door to the design of zeolites and layered compounds with tightly specified properties to provide the desired catalytic activity and separation selectivity. 

The development of new and improved catalysts requires advances in our understanding of how to make catalysts with specified properties the relationships between surface stracture, composition, and catalytic performance the dynamics of chemical reactions occurring at a catalyst surface the deployment of catalytic surface within supporting microstracture and the dynamics of transport to and from that surface. Research opportmuties for chemical engineers are evident in four areas catalyst synthesis, characterization of surface stracture, surface chemistry, and design. 

SPECIFY PROPERTIES AND/OR PROCESS RESULTS SPECIFY PROCESS TO BE USED... 

Material, sufficiently homogeneous and stable with respect to one or more specified properties, which has been established to be fit for its intended use in a measurement process. 

A reference material characterized by a metrologically valid procedure for one or more specified properties, accompanied by a certificate that states the value of the specified property, its associated uncertainty and a statement of metrological traceability. 

Klein, J. A., Wu, D. T. Gani, R. (1992) Computer aided mixture design with specified property constraints, Computers and Chemical Engineering, 16, S229. 

Replacement of Ethyl Glycol Step 1 Pre-Specified Properties... 

Replacement of Methylene Chloride Step 1 Pre-specified Properties... 

Homogeneity Condition of being of uniform structure or composition with respect to one or more specified properties. A reference material is said to be homogeneous with respect to a specified property if the property value, as determined by tests on samples of specified size, is found to lie within the specified uncertainty limits, the samples being taken either from different supply units (bottles, packages, etc.) or from a single supply unit. 

However, the graphical approach is not appropriate for finding the absolute accuracy between more than two properties. The well-established statistical technique of regression analysis is more pertinent to determining the accuracy of points derived from one property and any number of other properties. There are many instances in which relationships of this sort enable properties to be predicted from other measured properties with as good precision as they can be measured by a single test. It would be possible to examine in this way the relationships between aU the specified properties of a product and to establish certain key properties from which the remainder could be predicted, but that would be a tedious task. 

To address performance, the results of nonfunctionality tests are considered sufficient if the test and acceptance criteria are appropriate for the intended purpose. Tests described there are typically considered sufficient standards for establishing specified properties and characteristics of specified materials of construction or packaging components. For nonfunctionality tests, an applicant should provide justification for the use of the test, a complete and detailed description of how the test was performed, and an explanation of what the test is intended to establish. If a related test is available, comparative data should be provided using both methods. Supporting data should include a demonstration of the suitability of the test for its intended use and its validation. 

Figure 7.15. Optimal composition of PVDF/PMMA blend based on specified properties.

Design is the selection of variables (e.g., heat exchanger areas, maximum heater and cooler loads) which lead a given design structure (HEN topology or general process flow sheet) to have specified properties. 

A measurement of a specified property in an unknown material is a quantitative comparison by ratio or difference made of that property between a reference standard or reference material and the unknown or between relevant settings in an instrument, preferably in the appropriate unit for the quantity under investigation, provided ... 

The aim of the factory production is to produce, as economically as possible, a consistent product with the specified properties. The key points in achieving this are ... 

As noted in the introduction, a major aim of the current research is the development of "black-box" automated reactors that can produce particles with desired physicochemical properties on demand and without any user intervention. In operation, an ideal reactor would behave in the manner of Figure 12. The user would first specify the required particle properties. The reactor would then evaluate multiple reaction conditions until it eventually identified an appropriate set of reaction conditions that yield particles with the specified properties, and it would then continue to produce particles with exactly these properties until instructed to stop. There are three essential parts to any automated system—(1) physical machinery to perform the process at hand, (2) online detectors for monitoring the output of the process, and (3) decision-making software that repeatedly updates the process parameters until a product with the desired properties is obtained. The effectiveness of the automation procedure is critically dependent on the performance of these three subsystems, each of which must satisfy a number of key criteria the machinery should provide precise reproducible control of the physical process and should carry out the individual process steps as rapidly as possible to enable fast screening the online detectors should provide real-time low-noise information about the end product and the decision-making software should search for the optimal conditions in a way that is both parsimonious in terms of experimental measurements (in order to ensure a fast time-to-solution) and tolerant of noise in the experimental system. 

The essential feat me of Try lord, theory of turbulence is that it is unnecessary to suj.mhue anythinr about the motion of individual portions of a fluid in oust.- to iav. -y ig P..o such [properties as composition and momentum. Ic is ocly vccs ory to assume that such statistical calculations as exist between the. ciuv ami other specified properties of an element are fi.mct o urn-. or mace differences. If vt is the velocity of an element o) fluid in vom smmibv direction at time t, and vt -and vt + tf its velocity av. mb or. earlier and an instant later, respectively, the correlate) cot - cica- cb wav be written as follows ... 

Quantitative-structure-property relationship. A quantitative relationship between a specified property and the structure of a compound. Very similar to QSAR but of more relevance in coordination chemistry, where properties rather than activities are usually referred to. 

Each refinery has its own range of preferred crude oil feedstocks from which a desired product portfolio can be obtained. Crude oil typically is identified by its source country, underground reservoir, or some distinguishing physical or chemical property. The three most frequently specified properties are density, chemical characterization, and sulfur content. 

Equal. [Not all equals are equal.] The word equal and the symbol = have many different uses. The dictionary warns that equal things are alike or in agreement in a specified sense with respect to specified properties. This we must be careful about the specified sense and specified properties. 

Reference material, accompanied by documentation issued by an authoritative body and providing one or more specified property values with associated uncertainties and traceabilities, using valid procedures. 

It was assumed that the wake volume to bubble volume ratio, a, is a known constant and Vs can be determined if the bubble size is specified. It was further assumed that Vsup, a, m, and Vs are fixed. (This assumption is tantamount to the assumption of starting with liquid-fluidized bed at t = 0, or with a bed of specified properties and degree of expansion.) With these assumptions, Eqs. (197) and (198) were simplified to... 

After petroleum recovery and prior to the commencement of refining, there needs to be an estimate of the potential behavior of petroleum during refining operations. Briefly, three frequently specified properties that are used to evaluate petroleum are density (specific gravity, API gravity), characterization factor, and sulfur content (Matar, 1992 Speight, 1999 2000 2001). 

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