Dynamics

Every object experiences some form of motion which is the result of different forces acting on the object. Dynamics is the study of the forces which are responsible for this motion. Dynamics (from Greek δυναμικός dynamikos "powerful", from δύναμις dynamis "power") may refer to:

Physics and engineering

Rigid body dynamics

Rigid-body dynamics studies the movement of systems of interconnected bodies under the action of external forces. The assumption that the bodies are rigid, which means that they do not deform under the action of applied forces, simplifies the analysis by reducing the parameters that describe the configuration of the system to the translation and rotation of reference frames attached to each body. This excludes bodies that display fluid highly elastic, and plastic behavior.

The dynamics of a rigid body system is described by the laws of kinematics and by the application of Newton's second law (kinetics) or their derivative form Lagrangian mechanics. The solution of these equations of motion provides a description of the position, the motion and the acceleration of the individual components of the system and overall the system itself, as a function of time. The formulation and solution of rigid body dynamics is an important tool in the computer simulation of mechanical systems.

Dynamic (record label)

Dynamic is an Italian independent record label located in Genoa. Founded in 1978, it specialises in classical music and opera, especially rarely performed works and has produced several world premiere recordings. The Dynamic catalogue contains over 400 titles, with about 25 new titles added each year and is distributed in 32 countries.

History

Dynamic was founded in 1978 by Pietro Mosetti Casaretto and his wife Marisa. Mosetti Casaretto, a surgeon and amateur violinist, took over a small label founded by the musicologist Edward Neill. In the beginning, Dynamic was a small family business. Mosetti Casaretto and his wife recorded in local churches, oratories and villas. The first recordings were issued on vinyl, the very first one being Paganini's Barucabà Variations played by Salvatore Accardo.

In 1985 the company moved to its current site in the Villa Quartana on the Righi hill overlooking Genoa, where it set up a recording hall that could house a small chamber orchestra. In the late 1990s Mosetti Casaretto retired, and management of the label was taken over by his son-in-law, Alberto Dellepiane. Over the years, the label's focus on chamber music and particularly violin music has widened to include full-length opera recordings on both CD and DVD. More recently, Dynamic has become a high definition content producer for television and cinema.

Disorder

Disorder may refer to :

Disease

A disease is a particular abnormal condition, a disorder of a structure or function, that affects part or all of an organism. The causal study of disease is called pathology. Disease is often construed as a medical condition associated with specific symptoms and signs. It may be caused by factors originally from an external source, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune diseases. In humans, "disease" is often used more broadly to refer to any condition that causes pain, dysfunction, distress, social problems, or death to the person afflicted, or similar problems for those in contact with the person. In this broader sense, it sometimes includes injuries, disabilities, disorders, syndromes, infections, isolated symptoms, deviant behaviors, and atypical variations of structure and function, while in other contexts and for other purposes these may be considered distinguishable categories. Diseases usually affect people not only physically, but also emotionally, as contracting and living with a disease can alter one's perspective on life, and one's personality.

Entropy

In thermodynamics, entropy (usual symbol S) is a measure of the number of specific realizations or microstates that may realize a thermodynamic system in a defined state specified by macroscopic variables. Entropy is commonly understood as a measure of molecular disorder within a macroscopic system. According to the second law of thermodynamics the entropy of an isolated system never decreases. Such a system spontaneously evolves towards thermodynamic equilibrium, the state with maximum entropy. Systems that are not isolated may decrease in entropy, provided they increase the entropy of their environment by at least that same amount. Since entropy is a state function, the change in the entropy of a system is the same for any process that goes from a given initial state to a given final state, whether the process is reversible or irreversible. However, irreversible processes increase the combined entropy of the system and its environment.

The change in entropy (ΔS) of a system was originally defined for a thermodynamically reversible process as