Flight dynamics

Flight dynamics is the study of the performance, stability, and control of vehicles flying through the air or in outer space. It is concerned with how forces acting on the vehicle influence its speed and attitude with respect to time.

In fixed-wing aircraft, the changing orientation of the vehicle with respect to the local air flow is represented by two critical parameters, angle of attack ("alpha") and angle of sideslip ("beta"). These angles describe the vector direction of airspeed, important because it is the principal source of modulations in the aerodynamic forces and moments applied to the aircraft.

Spacecraft flight dynamics involve three forces: propulsive (rocket engine), gravitational, and lift and drag (when traveling through the earths or any other celestial atmosphere). Because aerodynamic forces involved with spacecraft flight are very small, this leaves gravity as the dominant force.

Aircraft and spacecraft share a critical interest in their orientation with respect to the earth horizon and heading, and this is represented by another set of angles, "yaw," "pitch" and "roll" which angles match their colloquial meaning, but also have formal definition as an Euler sequence. These angles are the product of the rotational equations of motion, where orientation responds to torque, just as the velocity of a vehicle responds to forces. For all flight vehicles, these two sets of dynamics, rotational and translational, operate simultaneously and in a coupled fashion to evolve the vehicle's state (orientation and velocity) trajectory.

List auf Sylt

List auf Sylt (known as List until 31 December 2008) is the northernmost municipality in Germany, located on the North Sea island of Sylt close to Denmark in the district of Nordfriesland in the state of Schleswig-Holstein.

Etymology

List derived from the Middle Low German Liste (ledge, bar or edge).

History

List was originally a Danish settlement. It was first mentioned in 1292 (Lystum). The original village was destroyed by the great flood of 1364. The settlement was rebuilt further east from the previous location. In the mid-15th century, a church named St. Jürgen was mentioned. In a treaty of 1460, Schleswig and Holstein were linked to the Danish crown, but List remained part of the royal enclaves, small areas of the Kingdom of Denmark situated within the Duchy of Schleswig, but directly controlled by the Danish king.

From the 16th century, the people of List mostly made a living from Oyster farming, raising sheep and collecting and selling gull eggs. At the time, List was an important protective anchorage. In 1644, a Swedish-Dutch fleet of 26 ships commanded by Admiral Thijssen was attacked in the Lister Tief and defeated by Danish ships commanded by king Christian IV of Denmark. The anchorage north of today's town was named Königshafen to honour this event.

List (abstract data type)

In computer science, a list or sequence is an abstract data type that represents an ordered sequence of values, where the same value may occur more than once. An instance of a list is a computer representation of the mathematical concept of a finite sequence; the (potentially) infinite analog of a list is a stream. Lists are a basic example of containers, as they contain other values. If the same value occurs multiple times, each occurrence is considered a distinct item.

The name list is also used for several concrete data structures that can be used to implement abstract lists, especially linked lists.

Many programming languages provide support for list data types, and have special syntax and semantics for lists and list operations. A list can often be constructed by writing the items in sequence, separated by commas, semicolons, or spaces, within a pair of delimiters such as parentheses '()', brackets '[]', braces '{}', or angle brackets '<>'. Some languages may allow list types to be indexed or sliced like array types, in which case the data type is more accurately described as an array. In object-oriented programming languages, lists are usually provided as instances of subclasses of a generic "list" class, and traversed via separate iterators. List data types are often implemented using array data structures or linked lists of some sort, but other data structures may be more appropriate for some applications. In some contexts, such as in Lisp programming, the term list may refer specifically to a linked list rather than an array.

List of Invader Zim characters

Invader Zim is an American animated television series created by Jhonen Vasquez and originally aired on Nickelodeon. The recurring cast includes long-term Nickelodeon voice actors Richard Steven Horvitz and Rodger Bumpass, with live-action television actors Kevin McDonald (The Kids in the Hall) and John de Lancie (Star Trek: The Next Generation). Vasquez voices parts in the show. The show was cancelled early in its run and some episodes were unfinished. The show ran for two seasons before its cancellation.

Main characters

Zim

Zim (voiced by Richard Steven Horvitz,Billy West in the pilot and Melissa Fahn as a smeet in "Parent Teacher Night") is an incompetent Irken invader who is foul-tempered, overzealous, impulsive, megalomaniac, and convinced of his own greatness. He dreams of regaining his leaders' trust by taking part in Operation Impending Doom II, so Zim is assigned to Earth, a planet which the Almighty Tallest believe has little to no chance of existing. However, against all odds, Zim makes it to Earth and establishes a base on a fake conquest mission. Because of his very small stature, Zim disguises himself as a human child using a hairpiece to cover his antennae and contact lenses to make his eyes look normal.

Tak (function)

In computer science, the Tak function is a recursive function, named after Ikuo Takeuchi (竹内郁雄). It is defined as follows:

This function is often used as a benchmark for languages with optimization for recursion.

tak() vs. tarai()

The original definition by Takeuchi was as follows:

tarai is short for tarai mawashi, "to pass around" in Japanese.

John McCarthy named this function tak() after Takeuchi.

However, in certain later references, the y somehow got turned into the z. This is a small, but significant difference because the original version benefits significantly by lazy evaluation. Though written in exactly the same manner as others, the Haskell code below runs much faster.

You can easily accelerate this function via memoization yet lazy evaluation still wins.

The best known way to optimize tarai is to use mutually recursive helper function as follows.

Here is an efficient implementation of tarai() in C:

Note the additional check for (x <= y) before z (the third argument) is evaluated, avoiding unnecessary recursive evaluation.

Tak (town)

Tak is a town (thesaban mueang) in north-west Thailand, capital of the Tak Province and the Tak district. As of 2005 the town had a population of 19,900 and an area of 7.27 km². It covers the tambon Rahaeng, Nong Luang, Chiang Ngoen, and Hua Diat. It is on the Ping River, 418 km north-north-west of Bangkok.

Geography

Tak is on the Ping River, which runs from north to south through the town. While the land to the east is fairly flat, the Tenasserim Hills and Dawna Range lie to the west.

Climate

Tak has a tropical savanna climate (Köppen climate classification Aw). Winters are dry and very warm. Temperatures rise until April, which is very hot with the average daily maximum at 38.5 °C (101.3 °F). The monsoon season runs from May through October, with heavy rain and somewhat cooler temperatures during the day, although nights remain warm.

Transportation

Route 105, through Mae Sot, forms one of two major transnational roads through the Tenasserim Hills to Burma. Route 1, also known as the Phahonyothin Road, passes through Tak. On the north side it leads to Lampang, Chiang Rai, and the border with Burma at Mae Sai. On the south side it leads to Kamphaeng Phet, Nakhon Sawan, and Bangkok. Route 12 leads east to Sukhothai, Phitsanulok, Chum Phae, Khon Kaen, Kalasin, and the border with Laos at Mukdahan.