barrel

A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden staves and bound by wood or metal hoops. The word vat is often used for large containers for liquids, usually alcoholic beverages; a small barrel or cask, typically with capacity of not more than ten gallons, is known as a keg.

barrel或cask是一个中空的圆柱形容器，中心凸起，形状细长。传统上，它们由木制的桶板制成，并用木头或金属箍捆绑。vat这个词通常用于盛装液体的大型容器，通常是酒精饮料；容量不超过10加仑的barrel或cask通常被称为keg。

Modern wooden barrels for wine-making are made of French common oak, white oak, or American white oak and typically have standard sizes: "Bordeaux type" 225 litres (59 US gal; 49 imp gal), "Burgundy type" 228 litres (60 US gal; 50 imp gal) and "Cognac type" 300 litres (79 US gal; 66 imp gal). 现代酿酒木桶由法国普通橡木、白橡木或美国白橡木制成，通常有标准尺寸：“波尔多型”225升（59美国加仑；49英磅加仑）、“勃艮第型”228升（60美国加仑；50英磅加仑）和“干邑型”300升（79美国加仑；66英磅加仑）。 In Britain, a gallon is equal to 4.564 litres. In America, it is equal to 3.785 litres.

A barrel is one of several units of volume applied in various contexts; there are dry barrels, fluid barrels (such as the U.K. beer barrel and U.S. beer barrel), oil barrels, and so forth. 桶是在各种情况下使用的几个体积单位之一；有干桶、液桶（如英国啤酒桶和美国啤酒桶）、油桶等。

In the worldwide oil industry, an oil barrel is defined as 42 US gallons, which is about 159 litres, or 35 imperial gallons. Oil companies that are listed on American stock exchanges typically report their production in terms of volume and use the units bbl (one barrel), or kbbl or Mbbl (one kilobarrel, one thousand barrels), or MMbbl (one million barrels), and occasionally for wider comprehensive statistics Gbbl (or sometimes Gbl), for giga-barrel (one billion barrels). There is a conflict concerning the units for oil barrels. For all other physical quantities, according to the International System of Units, the uppercase letter "M" means "mega-" ("one million"), for example: Mm (one million metres, megametres), MHz (one million hertz, or megahertz), MW (one million watts, or megawatt), MeV (one million electronvolt, or megaelectronvolt). But due to tradition, the Mbbl acronym is used today meaning "one thousand bbl", as a heritage of the roman number "M" meaning "one thousand". On the other hand, there are efforts to avoid this ambiguity, and most of the barrel dealers today prefer to use bbl, instead of Mbbl, mbbl, MMbbl or mmbbl.

https://solarsystem.nasa.gov/missions/mars-climate-orbiter/in-depth/
At 09:00:46 UT Sept. 23, 1999, the orbiter began its Mars orbit insertion burn as planned. The spacecraft was scheduled to re-establish contact after passing behind Mars, but, unfortunately, no signals were received from the spacecraft.

An investigation indicated that the failure resulted from a navigational error due to commands from Earth being sent in English units (in this case, pound-seconds) without being converted into the metric standard (Newton-seconds).

The error caused the orbiter to miss its intended orbit (87 to 93 miles or 140 to 50 kilometers) and to fall into the Martian atmosphere at approximately 35 miles (57 kilometers) in altitude and to disintegrate due to atmospheric stresses.

https://www.163.com/dy/article/FV3G7P3M0511DDSV.html
...
美国航天飞机“挑战者”号和“哥伦比亚”号，先后在1986年1月28日和2003年2月1日“机毁人亡”，各有7名宇航员殒命。这两次悲剧的原因并不是因为什么重大错误：前一次仅是一个密封圈破裂；后一次是外部燃料箱中的一块隔热泡沫碎片脱落，而这块碎片击中了航天飞机的左翼，使热防护部件形成裂孔，导致超高温气体在航天飞机重返大气层时进入了机体。

https://www.cnbc.com/2022/02/09/spacex-losing-starlink-satellites-due-to-geomagnetic-space-storm.html
Elon Musk's SpaceX expects to lose nearly an entire launch's worth of Starlink satellites after a storm created by the sun struck the Earth's atmosphere. The company launched 49 Starlink satellites on Feb. 3, but "up to 40 of the satellites" will be lost due to this geomagnetic storm.

https://www.ff.org/elon-musks-increasingly-bizarre-behavior-makes-him-an-even-worse-bet/
The King of All Government Money Recipients – is Elon Musk. Elon Musk's Growing Empire Is Fueled by $4.9 Billion in Government Subsidies That was written – in May 2015. More than years ago. That massive $5 billion tally – is unquestionably MUCH bigger now. Musk owns Solar City – a black hole solar panel company. And Musk merged Solar City with his Tesla – an electric car company. Which also receives tons of government dollars – both at the back end and at the point of sale. 所有政府资金接受者之王是埃隆·马斯克。2015年5月，埃隆·马斯克（Elon Musk）拿到了49亿美元的政府补贴，为其不断壮大的帝国提供了动力。多年前。50亿美元的巨额资金——毫无疑问，现在要多得多。马斯克拥有太阳城，一家黑洞太阳能电池板公司。马斯克将太阳能城与他的电动汽车公司特斯拉合并。在后端和销售点，它也收到大量政府资金。

A gun barrel is a crucial part of gun-type ranged weapons such as small firearms, artillery pieces and air guns. It is the straight shooting tube, usually made of rigid high-strength metal, through which a contained rapid expansion of high-pressure gas(es) is used to propel a projectile out of the front end (muzzle) at a high velocity. The hollow interior of the barrel is called the bore, and the diameter of the bore is called its caliber, usually measured in inches or millimetres. 枪管是小型火器、火炮和气枪等枪式远程武器的关键部件。它是一种直射管，通常由刚性高强度金属制成，通过它，高压气体的快速膨胀被用来以高速将弹丸推出前端（炮口）。枪管的中空内部称为枪膛，枪膛的直径称为口径，通常以英寸或毫米为单位。

In photography, barrel distortion is the distortion of an image produced by an optical system that causes straight lines at image margins to bulge outwards.