Acid

An acid (from the Latin acidus/acēre meaning sour) is a chemical substance whose aqueous solutions are characterized by a sour taste, the ability to turn blue litmus red, and the ability to react with bases and certain metals (like calcium) to form salts. An aqueous solution of an acid has a pH of less than 7 and is colloquially also referred to as 'acid' (as in 'dissolved in acid'), while the strict definition refers only to the solute. An acid usually contains a hydrogen atom bonded to a chemical structure that is still energetically favorable after loss of H⁺ (a positive hydrogen ion or proton). A lower pH means a higher acidity, and thus a higher concentration of positive hydrogen ions in the solution. Chemicals or substances having the property of an acid are said to be acidic.

There are three common definitions for acids: the Arrhenius definition, the Brønsted-Lowry definition, and the Lewis definition. The Arrhenius definition defines acids as substances which increase the concentration of hydrogen ions (H⁺), or more accurately, hydronium ions (H₃O⁺), when dissolved in water. The Brønsted-Lowry definition is an expansion to include solvents other than water: an acid is a substance which can act as a proton donor. By this definition, any compound which can be deprotonated can be considered an acid. Examples include alcohols and amines which contain O-H or N-H fragments. A Lewis acid is a substance that can accept a pair of electrons to form a covalent bond. Examples of Lewis acids include all metal cations, and electron-deficient molecules such as boron trifluoride and aluminium trichloride.

Drill

A drill is a tool fitted with a cutting tool attachment or driving tool attachment, usually a drill bit or driver bit, used for boring holes in various materials or fastening various materials together with the use of fasteners. The attachment is gripped by a chuck at one end of the drill and rotated while pressed against the target material. The tip, and sometimes edges, of the cutting tool does the work of cutting into the target material. This may be slicing off thin shavings (twist drills or auger bits), grinding off small particles (oil drilling), crushing and removing pieces of the workpiece (SDS masonry drill), countersinking, counterboring, or other operations.

Drills are commonly used in woodworking, metalworking, construction and do-it-yourself projects. Specially designed drills are also used in medicine, space missions and other applications. Drills are available with a wide variety of performance characteristics, such as power and capacity.

History

Around 35,000 BCE, Homo sapiens discovered the benefits of the application of rotary tools. This would have rudimentarily consisted of a pointed rock being spun between the hands to bore a hole through another material. This led to the hand drill, a smooth stick, that was sometimes attached to flint point, and was rubbed between the palms. This was used by many ancient civilizations around the world including the Mayans. The earliest perforated artifacts, such as bone, ivory, shells and antlers found, are from the Upper Paleolithic era.

Carol

Carol may refer to:

Music

People

Places

Other uses

And I

"And I" is a song written by American R&B singer Ciara, and produced by Adonis Shropshire for Ciara's first album, Goodies (2004). It was released as the album's fourth and final single on August 30, 2005 (see 2005 in music) in North America.

The song was originally the third choice for the fourth single. Ciara has mentioned in an interview that "Thug Style", "Hotline" or "Pick up the Phone" would be the fourth single, but when Ciara suggested "And I" to executives at her previous record label LaFace, they were unhappy because they wanted "Next to You" to be the fourth single.

Chart performance

At the time of the U.S. release of "And I", Ciara's collaboration with Bow Wow, "Like You", and her collaboration with Missy Elliott, "Lose Control", were at the height of their popularity. "And I" peaked at 96 on the U.S. Billboard Hot 100 and 27 on Billboard's Hot R&B/Hip-Hop Singles & Tracks chart, which were poor positions compared to those attained by the first three singles from the album Goodies. It was not released outside North America because of this, and it is Ciara's least successful single.

Carlos Vives

Carlos Alberto Vives Restrepo (born 7 August 1961) is a Colombian singer, composer and actor.

Biography

Carlos Vives was born on 7 August 1961 in Santa Marta, Magdalena, Colombia, where he spent his first 12 years of life. At that age, he and his family moved to Bogotá in search of a better life. They lived with Diego Martínez and his family. He enrolled in Jorge Tadeo Lozano University and holds a publicist degree from the university. In Bogota, he also acquired a taste for rock, getting involved in the local music scene, and started playing in bars and cafés around the city.

1982–1989

In 1982, Vives began acting in a number of shows and telenovelas including "Pequeños Gigantes" (Little Giants – 1983) and "Tuyo es Mi Corazón" (Yours is My Heart – 1985). He finally found fame in 1986 by playing the title role of Gallito Ramírez, which told the story of a Colombian Caribbean coast boxer who falls in love with an uptight girl, who was portrayed by his first wife, Margarita Rosa de Francisco. That same year, he released his first album, Por Fuera y Por Dentro. The album, primarily made of ballads, failed to gain any success. In 1987, he released his second ballad album, No Podrás Escapar de Mí. Though the title track reached No. 30 on the Billboard Hot Latin Tracks, the album did not sell well. His next album, Al Centro de la Ciudad, would become his last album to feature synthesizer-romantic ballads. Some of the songs got some attention being featured in telenovelas, but the album, just as its predecessors, failed to gain success.