Basic Terms

Before considering chromatographic theory in more detail it is important to understand the basic parameters. Fig. 2.2 shows a typical chromatogram, which represents the concentration of solute eluting from a column (as determined by the response of a sample detector) plotted against either time or volume. 

After injection of the sample onto the column the compounds that do not interact with the stationary phase will be eluted at time in the void volume Vq. The void volume represents the sum of the interstitial volume between the particles of the stationary phase and the accessible volume within the particle pores. The retention time of the sample (t,) is the time from injection to the time of maximum concentration in the eluted peak. The retention volume is the volume of solvent required to elute the solute as measured from the 

The retention volume is directly related to the distribution or partition coefficient of the solute (K) between the stationary and mobile phases  

The efficiency of a chromatographic column is measured by the number of theoretical plates (A ) to which the column is equivalent. The term was originally used to describe the process of distillation and can be visualised as a series of hypothetical layers in which the solute concentrations in the relevant phases are assumed to be in 

It is generally assumed that, initially, injection volumes will spread to give a Poisson distribution and then to a Gaussian distribution. A typical Gaussian peak is shown in Fig. 2.3. 

Before we look at some details of the analysis process, let us recall some basic important statistical terms. 

An accident is an incident plus its consequences the end product of a sequence of events or actions resulting in an undesired consequence (injury, property damage, interruption, delay). An accident can be defined more formally as an undesired event, which results in physical harm and/ or property damage, usually resulting from contact with a 

In normal conversation we use the word accident loosely, and in doing so we often couple in a sense of bad luck on the part of the injured person, and a feeling that it could not have been foreseen. In safety management, we need to be clear that the luck, or the element of chance, is only concerned with the physical outcome of the incident, which is that sequence of events or actions resulting in the undesired consequences . For ease of reading, this book uses the word accident to describe injury events, except where an important distinction has to be made between accident and incident . 

An injury is thus a consequence of an incident - but not the only possible one. It has been shown that hundreds of incidents occur in the construction industry for every one that causes injury or loss. But all have the potential to do so. That is why it is important to look at all incidents as sources of information on what is going wrong. Relying on injury records only allows a review of a minority of incidents - those which happened to result in a serious injury consequence. We can make some reasonable estimates about the likelihood of, say, failure of a lifting appliance. Only chance will decide whether an injury rather than, or as well as, property damage will occur on a particular occasion, and how severe either will be. 

Hazard means the inherent property or ability of something to cause harm - the potential to interrupt or interfere with a process or person . Hazards may arise from interacting or influencing components, for example two chemicals interacting to produce a third. 

Risk is the chance or probability of loss , an evaluation of the potential for failure. It is easy to confuse the terms hazard and risk , but a simple way to remember the difference is that hazard describes potential for harm. 

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Jenkins A D, Kratochvi I P, Stepto R F T and Suter U W 1996 Glossary of basic terms In polymer science Pure. Appl. Chem. 68 2287- 311... 

In addition to these basic term s. force fieldsoften h ave cross term s that combine the above interactions. For example there may be a term which causes ati angle bend to interact with a bond stretch term (opening a bond angle may tend to lengthen the bonds in volved). 

It is hoped that the improvements will help to achieve die objectives for which die text was originally conceived, i.e. to summarize in relatively basic terms die hazards associated with chemicals and how the ensuing risks can be controlled, and to provide sufficient detailed information to supplement that obtainable from suppliers, government publications, trade associations, and computerized data banks where recourse to specialized textbooks may be premature, difficult or unnecessary. 

There are three basic terms used in the chlorination process chlorine demand, chlorine dosage and chlorine residual. Chlorine demand is the amount of chlorine which will reduced or consumed in the process of oxidizing impurities in the water. Chlorine dosage is the amount of chlorine fed into the water. Chlorine residual is the amount of chlorine still remaining in water after oxidation takes place. For example, if a water has 2.0 ppm chlorine demand and is fed into the water in a chlorine dosage of 5.0 ppm, the chlorine residual would be 3.0 ppm. 

Design input requirements may in fact be detailed in the contract. The customer may have drawn up a specification detailing the features and characteristics product or service needs to exhibit. (See Part 1 Chapter 1 on Quality characteristics and Part 2 Chapter 3 under Ensuring that the requirements are adequately defined and documented.) Alternatively, the customer needs may be stated in very basic terms for example ... 

General equations are given first to identify the basic terms which correlate with ASME Pressure Vessel Gode, Section TII. 

This section will briefly review some of the basic terms used to discuss errors. It is not intended to be a comprehensive treatment of the topic. Here, we will simply consider the basic definitions. We will not attempt to derive or even explain the underlying theory. For more detailed treatments, please refer to the bibliography. 

Although these two forms of analysis give rise to somewhat similar expressions, the basic terms are evaluated in quite different ways and the final expressions show many differences. Some data fit the Rohsenow equation reasonably well<88), and other data fit Forster s equation. 

To characterize rheological behavior of materials, some basic terms need to be defined. Consider a liquid material that is subjected to a shearing force as illustrated in Fig. 2. The liquid is assumed to consist of a series of parallel layers with the surface area A, the bottom layer being fixed. When a force is applied on the top layer, the top plane moves at a constant velocity, whereas each lower layer moves with a velocity directly proportional to its distance from the stationary bottom layer. The velocity gradient (dv/dr, the difference in velocity, dv, between the top and bottom planes of liquid separated by the distance, dr) is also called the rate of shear, G ... 

Mahdihassan, S. A critical comparison of basic terms in Greek and Chinese systems of alchemy. Studs Hist Med 8, no. 3-4 (1984) 143-152. 

Mahdihassan, S. Basic terms of Greek alchemy in historial perspective. Janus 57, no. 1 (Jan 1970) 42-52. 

Translation schemes One particularly systematic approach to development encodes a selection of patterns as translation schemes. To move from requirements spec to detailed code, you choose a succession of translations. Template packages can be used to represent translation schemes. Another variety of translation scheme expresses the semantics of a language, such as UML, by defining how it translates to more basic terms. This technique is especially useful for stereotypes, the variable part of the UML notation. 

A. Terminological-descriptive Value Chain Management Chemical Industry and Value Chain Characteristics Define the research field and basic terms Use of descriptive studies to narrow problem area investigated within research field Definition of types and relevant dimensions in the scope... 

Research field and basic terms are now introduced in chapter 2. 

Finally, having introduced the basic terms and concepts, this book is itself introduced, and the recommended ways of reading and usage are described. 

The basic terms vp and dp and the liquid properties are made non-dimensional in the equations according to the similarity theory ... 

In basic terms, all automated analyses of samples in the hquid state are performed by one of two methods, discrete or continuous, and occasionally by a combination of the two. There are several basic subdivisions in each group and some examples will be described here and throughout the other chapters of the book to provide a starting platform for the systems designer. 

Glossary of basic terms in polymer science (lUPAC Recommendations 1996), Pure Appl. Chem. 68, 2287-2311 (1996). Reprinted as Chapter 1 this volume. 

Definitions of Basic Terms Relating to Low-Molar-Mass and Polymer Liquid Crystals... 

This document provides definitions of the basic terms that are widely used in the field of liquid crystals and in polymer science (See references 1-39). It is the first publication of the Commission on Macromolecular Nomenclature dealing specifically with liquid crystals. 

BASIC TERMS IN POLYMER MIXTURES 1.1 polymer blend... 

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