Shock (mechanics)

A mechanical or physical shock is a sudden acceleration caused, for example, by impact, drop, kick, earthquake, or explosion. Shock is a transient physical excitation.

Shock describes matter subject to extreme rates of force wtr to time. Shock is a vector that has units of an acceleration (rate of change of velocity). The unit g (or g) represents multiples of the acceleration of gravity and is conventionally used.

A shock pulse can be characterised by its peak acceleration, the duration, and the shape of the shock pulse (half sine, triangular, trapezoidal, etc.). The Shock response spectrum is a method for further evaluating a mechanical shock.

Shock measurement

Shock measurement is of interest in several fields such as

Acute stress reaction

Acute stress reaction (also called acute stress disorder, psychological shock, mental shock, or simply shock) is a psychological condition arising in response to a terrifying or traumatic event, or witnessing a traumatic event. It should not be confused with the unrelated circulatory condition of shock, or the concept of shock value.

"Acute stress response" was first described by Walter Cannon in the 1920s as a theory that animals react to threats with a general discharge of the sympathetic nervous system. The response was later recognized as the first stage of a general adaptation syndrome that regulates stress responses among vertebrates and other organisms.

Signs and symptoms

Common symptoms that sufferers of acute stress disorder experience are: numbing; emotional detachment; muteness; derealization; depersonalization; psychogenic amnesia; continued re-experiencing of the event via thoughts, dreams, and flashbacks; and avoidance of any stimulation that reminds them of the event. During this time, they must have symptoms of anxiety, and significant impairment in at least one essential area of functioning. Symptoms last for a minimum of 2 days, and a maximum of 4 weeks, and occur within 4 weeks of the event.

CSI: Miami (season 4)

The fourth season of CSI: Miami premiered on CBS on September 19, 2005 and ended May 22, 2006. The series stars David Caruso and Emily Procter.

Description

With a mole in their midst, Horatio and Calleigh head a team of elite Crime Scene Investigators as they enter their most challenging season yet. Under the roof of a state-of-the-art redesigned crime lab, the dynamic duo investigate a series of crimes including a night-club murder, the death of a pool boy, a cold case rape, and a murder with a double-jeopardy clause, all whilst under the scrutiny of an anonymous mole, and facing a series of cases that threaten the team. With Alexx accused of murdering a child molester, Horatio accused of murdering an innocent woman, Wolfe facing the loss of his eye, and Mac Taylor joining the team when a prisoner transfer goes awry, it's ultimately Delko that faces the greatest loss, when his sister is gunned down by the Mala Noche gang in an attack that will begin a narrative that will recur throughout the next several seasons.

Katana

Historically, katana (刀) were one of the traditionally made Japanese swords (日本刀, nihontō) that were used by the samurai of feudal Japan. Modern versions of the katana are sometimes made using non-traditional materials and methods. The katana is characterized by its distinctive appearance: a curved, slender, single-edged blade with a circular or squared guard and long grip to accommodate two hands.

History

The production of swords in Japan is divided into specific time periods:

The first use of "katana" (gatana) as a word to describe a long sword that was different from a tachi occurs as early as the Kamakura Period (1185–1333). These references to "uchigatana" and "tsubagatana" seem to indicate a different style of sword, possibly a less costly sword for lower-ranking warriors. The evolution of the tachi into the katana seems to have started during the early Muromachi period (1337 to 1573). Starting around the year 1400, long swords signed with the "katana" signature were made. This was in response to samurai wearing their tachi in what is now called "katana style" (cutting edge up). Japanese swords are traditionally worn with the signature facing away from the wearer. When a tachi was worn in the style of a katana, with the cutting edge up, the tachi's signature would be facing the wrong way. The fact that swordsmiths started signing swords with a katana signature shows that some samurai of that time period had started wearing their swords in a different manner.

Katana (disambiguation)

Katana is Japanese for backsword and often refers to uchigatana, especially in English. For a list of fictional katana, see Katanas in fiction. Katana may also refer to:

Dreamcast

The Dreamcast (Japanese: ドリームキャスト, Hepburn: Dorīmukyasuto) is a home video game console released by Sega on November 27, 1998 in Japan, September 9, 1999 in North America, and October 14, 1999 in Europe. It was the first in the sixth generation of video game consoles, preceding Sony's PlayStation 2, Nintendo's GameCube and Microsoft's Xbox. The Dreamcast is Sega's final home console, marking the end of the company's 18 years in the console market.

In contrast to the expensive hardware of the unsuccessful Sega Saturn, the Dreamcast was designed to reduce costs with "off-the-shelf" components, including a Hitachi SH-4 CPU and an NEC PowerVR2 GPU. Released in Japan to a subdued reception, the Dreamcast enjoyed a successful U.S. launch backed by a large marketing campaign, but interest in the system steadily declined as Sony built hype for the upcoming PlayStation 2. Sales did not meet Sega's expectations despite several price cuts, and the company continued to incur significant financial losses. After a change in leadership, Sega discontinued the Dreamcast on March 31, 2001, withdrawing from the console business and restructuring itself as a third-party publisher. 9.13 million Dreamcast units were sold worldwide.