Chalk (disambiguation)
Chalk may refer to:
Surname
Magnesium carbonate
Magnesium carbonate, MgCO3 (archaic name magnesia alba), is an inorganic salt that is a white solid. Several hydrated and basic forms of magnesium carbonate also exist as minerals.
Forms
The most common magnesium carbonate forms are the anhydrous salt called magnesite (MgCO3) and the di, tri, and pentahydrates known as barringtonite (MgCO3·2 H2O), nesquehonite (MgCO3·3 H2O), and lansfordite (MgCO3·5 H2O), respectively. Some basic forms such as artinite (MgCO3·Mg(OH)2·3 H2O), hydromagnesite (4 MgCO3·Mg(OH)2·4 H2O), and dypingite (4 MgCO3· Mg(OH)2·5 H2O) also occur as minerals.
Magnesite consists of white trigonal crystals. The anhydrous salt is practically insoluble in water, acetone, and ammonia. All forms of magnesium carbonate react in acids. Magnesium carbonate crystallizes in the calcite structure where in Mg2+ is surrounded by six oxygen atoms. The dihydrate one has a triclinic structure, while the trihydrate has a monoclinic structure.
References to 'light' and 'heavy' magnesium carbonates actually refer to the magnesium hydroxy carbonates hydromagnesite and dypingite (respectively).
Chalk (military)
In military terminology, a chalk is a group of paratroopers or other soldiers that deploy from a single aircraft. A chalk often corresponds to a platoon-sized unit for air assault operations, or a company-minus-sized organization for airborne operations. For air transport operations, it can consist of up to a company-plus-sized unit. Oftentimes, a load of paratroopers in one aircraft, prepared for a drop, is also referred to as a stick.
The term was first coined in World War II for airborne troops during Operation Overlord, the Allied invasion of Europe. The aircraft flight number was placed on the troops' backs with chalk. It was later used during the Vietnam War, when it was common practice to number with chalk the sides of the helicopters involved in an operation. During the Battle of Mogadishu (1993), the battle plan called for four chalks from the 75th Ranger Regiment to fast rope down from hovering MH-60L Black Hawk helicopters around the target building. The rangers would then create a four-corner defensive perimeter. The plan failed as two of the Black Hawks were shot down, and the assault turned into a forced evacuation.
Jason (surname)
Jason is a surname. Notable people with the surname include:
See also
List of companions in Doctor Who spin-offs
This is a list of fictional characters who were companions of the Doctor, in various spin-off media based on the long-running British science fiction television series, Doctor Who.
A
ARC
traveled with the 11th doctor
Alex Campbell
Alex is the Doctor's great grandson (the son of Susan Campbell) and features in the Eighth Doctor adventures. He is portrayed by Jake McGann.
He is initially wary of the Doctor due to the xenophobic atmosphere on Earth following the Dalek occupation. Despite this, he eventually accepts the Doctor but while he is impressed by the technology of the TARDIS he chooses not to travel with him as he wants to become an architect.
During the second Dalek invasion in the plays Lucie Miller and To The Death, Alex becomes a leader for the human resistance on Earth. He sacrifices himself to allow Lucie and Susan the opportunity to thwart the Dalek's plan.
Amy
Amy, portrayed by Ciara Janson, is a companion of the Fifth Doctor in the Key 2 Time series, which includes the plays The Judgement of Isskar, The Destroyer of Delights and The Chaos Pool.
Jason (cartoonist)
John Arne Sæterøy (born 16 May 1965), better known by the pen name Jason, is a Norwegian cartoonist, known for his sparse drawing style and silent, anthropomorphic animal characters.
He has been nominated for two Ignatz Awards (2000: Outstanding Story and Outstanding Series, 2001: Outstanding Story and Outstanding Series), has received praise in Time, and won the Harvey Award for best new talent in 2002, and several Eisner Awards.
Biography
Jason was born in Molde, and had his work published for the first time in 1981 in the Norwegian comics magazine KonK, to which he contributed several short stories during its lifespan. In 1989, he was admitted to Norway's National Academy of the Arts, where he studied graphical design and illustration. He won the Norwegian Comics Association award in 1991 for the short work pervo.
In 1995, Jason published his first graphic novel, Lomma full av regn (Pocket Full of Rain), for which he won the Sproing Award. In 1997, he started making Mjau Mjau, a semi-regular comic book featuring nothing but his own works. In 2001, he was once again awarded a Sproing, this time for Mjau Mjau 10. Since 2002, Jason has concentrated on making graphic novels.
