Where did the term crack shot come from?
Where did the term crack shot come from?
Adjectival meaning “top-notch, superior” (as in a crack shot) is slang from 1793, perhaps from earlier verbal sense of “do any thing with quickness or smartness”.
What does good shot mean?
a good marksman
What are shots in photography?
The term “shot” can refer to two different parts of the filmmaking process: In production, a shot is the moment that the camera starts rolling until the moment it stops. In film editing, a shot is the continuous footage or sequence between two edits or cuts.
What is an example of cracking?
Cracking, as the name suggests, is a process in which large hydrocarbon molecules are broken down into smaller and more useful ones, for example: The cracking products, such as ethene, propene, buta-1,3-diene and C4 alkenes, are used to make many important chemicals.
What can butane be cracked into?
Commercially, n-butane can be added to gasoline to increase its volatility. Transformed to isobutane in a refinery process known as isomerization, it can be reacted with certain other hydrocarbons such as butylene to form valuable high-octane constituents of gasoline.
What can Octane be cracked into?
Q1. This question is about fuels. Octane (C8H18) is a hydrocarbon in petrol. (a) Cracking breaks down large hydrocarbon molecules into smaller hydrocarbon molecules.
What is required for catalytic cracking?
The catalytic cracking process involves the presence of solid acid catalysts, usually silica-alumina and zeolites. The catalysts promote the formation of carbocations, which undergo processes of rearrangement and scission of C-C bonds.
What is cracking in cyber crime?
Cracking is when someone performs a security hack for criminal or malicious reasons, and the person is called a “cracker.” Just like a bank robber cracks a safe by skillfully manipulating its lock, a cracker breaks into a computer system, program, or account with the aid of their technical wizardry.
Is Cracking a reversible reaction?
Cracking of ethane into ethylene and hydrogen is a reversible reaction. Thus, steam is introduced into the feed stream to reduce the partial pressure of ethane. Since steam is inert (no reaction with ethane or other components), its presence does not produce by-products.
What causes thermal cracking in asphalt?
Thermal cracking is primarily a result of the low temperature environment. After the thermal crack develops, water can enter the crack and cause ravelling of the joint and/or loss of base support. This significantly decreases the rideability of the pavement.
How do you keep concrete from cracking in the heat?
To maintaining cool concrete in hot weather, the temperature within the concrete can be reduced by using cool water or ice as part of the mixing water. Additionally, spraying aggregates with water can help keep the concrete cool.
What is the best weather for pouring concrete?
Experts agree—the best temperature to pour concrete is between 40° – 60°F. When temperatures dip below 40°F, the chemical reactions that strengthen concrete slow down and can lead to weaker concrete. According to the American Concrete Institute, hot weather is more than air temperature.
What causes stress cracks in windows?
Stress cracks are a naturally occurring result of expanding and contracting glass due to temperature changes. However, installing thicker glass and choosing glass features based on your climate and sun exposure needs may help decrease your risk.
Can Windows just crack?
Cracks can occur even when a window is not struck. The most common cause of inexplicable cracks in windows is stress. Stress cracks—also referred to as thermal stress cracks—can occur in windows when a thermal gradient causes the glass in your window to expand by different amounts in different parts of the window.
Can a window crack by itself?
The short answer is: not really. Stress cracks are a naturally occurring result of expanding and contracting glass due to temperature changes. However, installing thicker glass and choosing glass features based on your climate and sun exposure needs may help decrease your risk.
Can a window glass crack by itself?
Is Spontaneous Glass Breakage Normal? While rare, spontaneous glass breakage does happen sometimes in double-paned windows, due to the pressurized gas between the panes. It can also happen to tempered glass, which is a tougher type of glass that has been treated with heat and chemicals to withstand high impacts.
Why would a double pane window crack?
Many of these cracks occur as a result of installation mistakes. If the window insulation doesn’t match the elevation level, the pressure can cause the glass to break. Unfortunately, thermal stress cracks are not a rare thing. Extreme temperature fluctuations cause the glass to expand and contract.