Chemical and Process

A chemical substance is any material substance used in or obtained by a process in chemistry. It can be an element, a compound, or a mixture thereof:

• A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions.
• A chemical element is a substance that cannot be divided or changed into different substances by ordinary chemical methods. The smallest particle of such an element is an atom, which consists of electrons centered on a nucleus of protons and neutrons.

• A molecule is the smallest particle of an element or compound that retains the characteristics of the element or compound.

• An ion is an atom or a molecule with a net electric charge, having lost (cation) or gained (anion) an electron.

• A chemical reaction is a process involving one, two or more substances (called reactants), characterized by a chemical change and yielding one or more product(s) which are different from the reactants.

Look up Process in Wiktionary, the free dictionary

Process (lat. processus - movement) is a naturally occurring or designed sequence of operations or events, possibly taking up time, space, expertise or other resource, which produces some outcome. A process may be identified by the changes it creates in the properties of one or more objects under its influence. Compare: project. See also: process management, process theory, and Category:Nature.

Examples

A process may be categorized as singular, recurrent, or periodic. A singular process would be one which occurs only once. Few processes in nature can be considered singular. Most processes found in nature are recurrent, or repeat more than once. Recurring processes which repeat at a constant rate are considered periodic. The more periodic a process is the more useful it is as the basis of a clock. Below are a few specific examples of processes.

• The Bessemer process is a way of producing steel.
• The process of mining extracts ore.
• Evolution is a natural process which explains the adaptation of species over long peroids of time. (generally assumed to be an example of a recurrent process)
• The creation of the universe by God would be an example of a divine process. (generally assumed to be a singular process)
• Process music
• Civic governance and conflict resolution
• Error correction in the information processing of a stream of data.
• Protein biosynthesis

Art

See process music and Sol Lewitt.

Business

Businesses organize interactions by means of business processes.

Computing

Computing has many concepts of process.

Program execution

In computing, a computer process is a running instance of a program, including all variables and other states. A multitasking operating system switches between processes to give the appearance of simultaneous execution, though in fact, in general, only one process can be executing per CPU core. Some new processors, such as Intel's Pentium 4 with Hyperthreading capability, can actually execute two proceses at a time, because some parts of the core are doubled. More companies announced development of multicore processors.

Software development

A software development process is a sequence of steps that practitioners and managers take to create software. The steps usually include requirements analysis, programming, testing, and other steps.

Different processes mix the steps together in different ways, and assign responsibility to people in different ways.

The CMM is a meta-process that defines rigid goals up front, and emphasizes scientific management. Some dislike its emphasis on paperwork.

Agile processes take the opposite approach, making things flexible.

In SSADM a process is a part of a data flow diagram, and represents an action performed on the data.

Information system development

In the context of Information System Development a process is performed to produce a product. Such processes are also called techniques.

Products represent what shall be constructed, e.g. class diagrams, state charts, and so on. Processes (techniques) are the procedures which describe in what order the construction of the products shall be performed, e.g. “at first, identify classes and objects” to construct a class diagram, “identify states”, and so on. In [Rolland1993] the term process is defined as “a related set of activities conducted to the specific purpose of product definition”.

Both together, the set of products and their corresponding processes/techniques form a Method [Saeki] [Rolland1998]. Processes of the same nature are classified together into a Process Model.

References

Engineering

Chemical engineering

A chemical process is a series of unit operations used to produce a material in large quantities.

In the chemical industry, chemical engineers will use the following to define or illustrate a process:

• Process Flow Diagram (PFD)
• Piping and Instrumentation Diagram (P&ID)
• Simplified Process Description
• Detailed Process Description

Philosophy

In philosophy and systems theory, basic processes, or logical homologies as they were termed by Ludwig von Bertalanffy, are unifying principles which operate in many different systemic contexts. For example, feedback is a principle that figures prominently in the science of cybernetics. Natural and industrial processes utilize basic processes such as feedback.

There is a philosophical system known as process philosophy, created by Alfred North Whitehead; related to this is process theology.

References

• Ludwig von Bertalanffy, General System Theory, George Braziller, New York, 1968, pages 84,85 ISBN 0807604534

External links

• Article defining process in Principia Cybernetica Web

Processes in Science

Any method (or event) that results in a transformation in a physical or biological object, a substance or an organism, is a process in science. Some example of such processes are: activation, combustion, crystallization, centrifugation, diffraction, dispersion, distillation, electrolysis, electrophoresis, emulsification, evaporation, hydrolysis, nuclear fission, nuclear fusion, oxidation, phosphorescence, pyrolysis, reduction, reflection, refraction, scattering, sedimentation, sublimation are a few examples of common processes in physical sciences. Similarly, birth, cell division, fermentation, fertilization, germination, growth, geotropism, heliotropism, hybridization, metamorphosis, photosynthesis, transpiration are a few examples of biological processess.

See also

• Stochastic process
• Process group