Objects, Properties and Methods

VBA is an object-oriented programming language. Objects in Microsoft Excel are the familiar components of Excel, such as a worksheet, a chart, a toolbar or a range. Objects have properties and methods associated with them. Objects are the nouns of the language, properties are the adjectives, and methods are the verbs. 

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There are literally hundreds of VBA objects, properties and methods, and this can be confusing for the beginner. Chapter 14 focused cn the basic tools needed to create macros to automate chemical worksheet calculations how to transfer values from a sheet to a VBA module, how to perform calculations within a VBA module, how to perform logical branching and iterative looping, and how to send values back from a VBA module to a worksheet. In this chapter we ll use these tools to create some useful Sub procedures. 

VBA macro code consists of statements. Statements are constructed by using VBA commands, operators, variables, functions, objects, properties or methods. (VBA Help refers to keywords such as Beep, Do or Exit as statements, but here they ll be referred to as commands, and we ll use "statement" in a general way to refer to a line of VBA code.)... 

Just as objects can contain many other objects, a specific object can have several properties and methods. For instance, a cell can have as properties an address, a formula, and a value, and as methods we can select it, clear it, copy it, and so on. 

Because Range is such a common object in VBA, it can be combined with many different properties and methods. You can Activate a Range, Clear it, Copy it, Cut it, Delete it, and so on. You can also ask for the Address of a Range, for its Areas, Cells, Columns, Count, EntireRow, Formula, Format, etc. You can also refer to entire regions of the worksheet with instructions such as CurrentRegion or UsedRange. For the precise definitions of these, and examples of their use, refer to the Visual Basic Help file, which comes with Excel but may have to be installed if it was left out during the initial installation procedure. 

Table 1. Standard Properties and Methods of a COM Collection Object Shepherd and King (1999).

The property node automatically adapts to the class of the object that is referenced. The property node can also be used to get or set properties and methods on local or remote application instances and Vis. If the property node class is application or VI, refnum is not used. For the application class, the default is the current application instance. For the VI class, the default is the VI containing the property node. Further, the property node can be used to access the private data of a Lab VIEW class. 

A challenging task in material science as well as in pharmaceutical research is to custom tailor a compound s properties. George S. Hammond stated that the most fundamental and lasting objective of synthesis is not production of new compounds, but production of properties (Norris Award Lecture, 1968). The molecular structure of an organic or inorganic compound determines its properties. Nevertheless, methods for the direct prediction of a compound s properties based on its molecular structure are usually not available (Figure 8-1). Therefore, the establishment of Quantitative Structure-Property Relationships (QSPRs) and Quantitative Structure-Activity Relationships (QSARs) uses an indirect approach in order to tackle this problem. In the first step, numerical descriptors encoding information about the molecular structure are calculated for a set of compounds. Secondly, statistical and artificial neural network models are used to predict the property or activity of interest based on these descriptors or a suitable subset. 

The most effective specification is that which accomplishes the desired result with the fewest requirements. Properties and performance should be emphasized rather than how the objectives ate to be achieved. Excessive demonstration of emdition on the part of the writer or failure to recognize the usually considerable processing expertise held by the vendor results in a lengthy and overly detailed document that generally is counterproductive. Redundancy may lead to technical inconsistency. A requirement that cannot be assessed by a prescribed test method or quantitative inspection technique never should be included in the specifications. Wherever possible, tests should be easy to perform and highly correctable with service performance. Tests that indicate service life are especially useful. Standard test references, eg, ASTM methods, ate the most desirable, and those that ate needed should be selected carefully and the numbers of such references should be minimized. To eliminate unnecessary review activity by the would-be complier, the description of a standard test should not be paraphrased or condensed unless the original test is referenced. 

Chemical binders are appHed to webs in amounts ranging from about 5 to 60 wt %. In some instances when clays (qv) or other weight additives ate included, add-on levels can approach or even exceed the weight of the web. Waterborne binders ate appHed by spray, saturation, print, and foam methods. A general objective of each method is to apply the binder material in a manner sufficient to interlock the fibers and provide chemical and mechanical properties sufficient for the intended use of the fabfic. 

The objectives of this review are to discuss the fundamental and more recently discovered properties of water alone and to critically examine the system properties and measurement methods used to measure the mobility of water and solids in foods—specifically water activity, nuclear magnetic resonance (NMR), and the glass transition. 

The object of this work was to extend the field of application of the equation-of-state method. The method was applied to aqueous systems in conjunction with a model that treats water as a mixture of a limited number of polymers, an approach similar to that previously adopted for the carboxylic acids (2). Association is calculated by the law of mass action corrections for non-ideal behaviour are made by means the equation of state. A major problem of the method is the large number of parameters needed to describe the properties and concentrations of the polymers together with their interaction with molecules of other substances. The Mecke-Kemptner model (15) (also known as the Kretschmer-Wiebe model (16) and experimental values for hydrogen-bond energies were usecT for guidance in fixing these parameters. 

We have now concluded our consideration of the theory and methods of chemical thermodynamics. Our primary objective, to establish the principles and procedures by which the thermodynamic properties associated with a given transformation can be determined, has been acheived, and we have learned how these quantities can be used to judge the feasibility of that transformation. 

Active control of wettability is a subject of current research activity and is beyond our scope here. However, the first step in this process is a study of interfacial tension and contact angle, their basis in thermodynamics, and methods to measure these properties. This is the objective of this chapter. 

First, there is the obvious objection that there may be no experimental values for the properties and systems of interest. Second (and almost as obvious) is the possibility that the experimental values are wrong. Third, the experimental values may in fact be derived from experimental measurements by a number of steps that involve assumptions or other theoretical calculations. All of these objections are important, but in one sense they are orthogonal to the real issue what if our calculations contain multiple sources of error that can cancel with one another We know already that any truncated one-particle space and truncated jV-particle space treatment has two sources of error, these two truncations. And there is no reason to suppose that the error from these two sources cannot cancel, indeed, from the early days of large-scale correlated atomic wave functions there is good evidence that they do cancel [35]. Hence even if there are absolutely reliable experimental values for the properties and molecules we want to consider, using them to calibrate theoretical methods may be useless unless we can establish whether we have a cancellation of errors or not. 

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