Intex 18 ft. x 52 in. Ultra XTR Frame Round Above Ground Swimming Pool Set with Pump

Eighteen or 18 may refer to:

• 18 (number), the natural number following 17 and preceding 19
• one of the years 18 BC, AD 18, 1918, 2018 1818

52 may refer to:

• 52 (number)
• one of the years 52 BC, AD 52, 1952, 2052
• 52-hertz whale an individual male whale, also known as the loneliest whale, calling at the unusual 52 hertz range
• 52 (comics), a 2006–07 American weekly comic book series
• 52 (album series), series of albums by American singer Kristian Bush
• 52 Europa, a main-belt asteroid
• Tatra 52, a mid-size car

Above may refer to:

• Above (artist), Tavar Zawacki (born 1981), contemporary urban artist
• Above (magazine), an American environmental magazine 2009–2010
• Above (Mad Season album), 1995
• Above (Pillar album), 2000
• Above (Samael album), 2009
• "Above", a song by Finger Eleven from Tip

A frame is often a structural system that supports other components of a physical construction and/or steel frame that limits the construction's extent.

Frame and FRAME may also refer to:

A pump is a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic energy.

Mechanical pumps serve in a wide range of applications such as pumping water from wells, aquarium filtering, pond filtering and aeration, in the car industry for water-cooling and fuel injection, in the energy industry for pumping oil and natural gas or for operating cooling towers and other components of heating, ventilation and air conditioning systems. In the medical industry, pumps are used for biochemical processes in developing and manufacturing medicine, and as artificial replacements for body parts, in particular the artificial heart and penile prosthesis.

When a pump contains two or more pump mechanisms with fluid being directed to flow through them in series, it is called a multi-stage pump. Terms such as two-stage or double-stage may be used to specifically describe the number of stages. A pump that does not fit this description is simply a single-stage pump in contrast.

In biology, many different types of chemical and biomechanical pumps have evolved; biomimicry is sometimes used in developing new types of mechanical pumps.

Swimming is the self-propulsion of a person through water or other liquid, such as saltwater or freshwater environments, usually for recreation, sport, exercise, or survival. Swimmers achieve locomotion by coordinating limb and body movements to achieve hydrodynamic thrust that results in directional motion. Newborns can instinctively hold their breath underwater and exhibit rudimentary swimming movements as part of a survival reflex. Swimming requires endurance, skill, and efficient techniques to maximize speed and minimize energy consumption.

Swimming is a popular activity and competitive sport where certain techniques are deployed to move through water. It offers numerous health benefits, such as strengthened cardiovascular health, muscle strength, and increased flexibility. It is suitable for people of all ages and fitness levels.

Swimming is consistently among the top public recreational activities, and in some countries, swimming lessons are a compulsory part of the educational curriculum. As a formalized sport, swimming is featured in various local, national, and international competitions, including every modern Summer Olympics.

Swimming involves repeated motions known as strokes to propel the body forward. While the front crawl, also known as freestyle, is widely regarded as the fastest of the four main strokes, other strokes are practiced for special purposes, such as training.

Swimming comes with certain risks, mainly because of the aquatic environment where it takes place. For instance, swimmers may find themselves incapacitated by panic and exhaustion, both potential causes of death by drowning. Other dangers may arise from exposure to infection or hostile aquatic fauna. To minimize such eventualities, most facilities employ a lifeguard to keep alert for any signs of distress.

Swimmers often wear specialized swimwear, although depending on the area's culture, some swimmers may also swim nude or wear their day attire. In addition, a variety of equipment can be used to enhance the swimming experience or performance, including but not limited to the use of swimming goggles, floatation devices, swim fins, and snorkels.

With or WITH may refer to:

• With, a preposition in English
• Carl Johannes With (1877–1923), Danish doctor and arachnologist
• With (character), a character in D. N. Angel
• With (novel), a novel by Donald Harrington
• With (album), a 2014 album by TVXQ
• With (EP), a 2021 EP by Nam Woo-hyun

X, or x, is the twenty-fourth letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ex (pronounced ), plural exes.

In cryptography, XTR is an algorithm for public-key encryption. XTR stands for 'ECSTR', which is an abbreviation for Efficient and Compact Subgroup Trace Representation. It is a method to represent elements of a subgroup of a multiplicative group of a finite field. To do so, it uses the trace over ${\displaystyle GF(p^{2})}$ to represent elements of a subgroup of ${\displaystyle GF(p^{6})^{*}}$.

From a security point of view, XTR relies on the difficulty of solving Discrete Logarithm related problems in the full multiplicative group of a finite field. Unlike many cryptographic protocols that are based on the generator of the full multiplicative group of a finite field, XTR uses the generator ${\displaystyle g}$ of a relatively small subgroup of some prime order ${\displaystyle q}$ of a subgroup of ${\displaystyle GF(p^{6})^{*}}$. With the right choice of ${\displaystyle q}$, computing Discrete Logarithms in the group, generated by ${\displaystyle g}$, is, in general, as hard as it is in ${\displaystyle GF(p^{6})^{*}}$ and thus cryptographic applications of XTR use ${\displaystyle GF(p^{2})}$ arithmetics while achieving full ${\displaystyle GF(p^{6})}$ security leading to substantial savings both in communication and computational overhead without compromising security. Some other advantages of XTR are its fast key generation, small key sizes and speed.