In fact, because of atmospheric refraction and because the sun appears as a disk and not a point, part of the midnight sun may be seen on the night of the northern summer solstice up to about 50 ′ () south of the Arctic Circle ; similarly, on the day of the northern winter solstice, part of the sun may be seen up to about 50 ′ north of the Arctic Circle.

In two dimensions, closed disks are compact since for any infinite number of points sampled from a disk, some subset of those points must get arbitrarily close either to a point within the disc, or to a point on the boundary.

However, an open disk is not compact, because a sequence of points can tend to the boundary without getting arbitrarily close to any point in the interior.

The light is not focused to a point but forms an Airy disk having a central spot in the focal plane with radius to first null of

The Rayleigh criterion specifies that two point sources can be considered to be resolvable if the separation of the two images is at least the radius of the Airy disk, i. e. if the first minimum of one coincides with the maximum of the other.

As the 1980s began, hard disk drives were a rare and very expensive additional feature on personal computers ( PCs ); however by the late ' 80s, their cost had been reduced to the point where they were standard on all but the cheapest PC.

In fact, f coincides with its Taylor series at a in any disk centered at that point and lying within the domain of the function.

MMC allows a sequencer to send " Start ", " Stop ", and " Record " commands to a connected tape deck or hard disk recording system, and to fast-forward or rewind the device so that it starts playback at the same point as the sequencer.

Over this was placed a circular disk of paper ; an electromagnet with the embossing point connected to an arm travelled over the disk ; and any signals given through the magnets were embossed on the disk of paper.

For example, the sphere and torus are orientable, while the real projective plane is not ( because deleting a point or disk from the real projective plane produces the Möbius strip ).

With the disk drive top removed a small screwdriver could be used to slow the drive RPM below a certain point.

This disk has perforations through which each of the strands pass, thence being immediately wrapped on the cable, which slides through a bearing at this point.

* Universal micrometer sets come with interchangeable anvils, such as flat, spherical, spline, disk, blade, point, and knife-edge.

The monument consists of a granite disk embedded with a smaller bronze disk around the point, surrounded by smaller, appropriately located state seals and flags representing both the states and tribal nations of the area.

Circling the point, with two words in each state, the disk reads, " Four states here meet in freedom under God.

It is a subtle point even today that a real algebraic plane curve cannot enter a disk without leaving.

The point x, represented by a dot to the left of the picture, and the closed set F, represented by a closed disk to the right of the picture, are separated by their neighbourhoods U and V, represented by larger open disk s. The dot x has plenty of room to wiggle around the open disk U, and the closed disk F has plenty of room to wiggle around the open disk V, yet U and V do not touch each other.

According to the Internet Accuracy Project, disk jockey-singer J. P. " The Big Bopper " Richardson was the first to coin the phrase " music video ", in 1959.

In mathematics, the open unit disk ( or disc ) around P ( where P is a given point in the plane ), is the set of points whose distance from P is less than 1:

* David P. Helmbold, " A dynamic disk spin-down technique for mobile computing ", citeseer. ist. psu. edu, 1996

In P. baronii, the disk is composed of five unequal glands, where 2 or 2 pairs are fused partly or entirely.

When memory is near full, the MCP examines the working set, trying compaction ( since the system is segmented, not paged ), deallocating read-only segments ( such as code-segments which can be restored from their original copy ), and as a last resort, rolling dirty data segments out to disk.

Today DC motors are still found in applications as small as toys and disk drives, or in large sizes to operate steel rolling mills and paper machines.

The disk, when spun on the mirror, exhibits a spinning / rolling motion ( or spolling, a blend of " spin " and " roll "), slowly moving through different rates and types of motion before coming to rest – for example, the precession rate of the axis of symmetry accelerates as the disk spins down.

A spinning / rolling disk ultimately comes to rest ; and it does so quite abruptly, the final stage of motion being accompanied by a whirring sound of rapidly increasing frequency.

Moffatt's work inspired several other workers to investigate the dissipative mechanism of a spinning / rolling disk, whose results contradicted his explanation.

Railroads have been using disk brakes on passenger cars for more than 60 years, but coupled with a Rolokron anti-lock system to avoid the creation of flat spots ( or “ square wheels ”) when wheels lock and skid on the rail surface ( audible as steady bang-bang-bang noise as a train goes by — not to be confused with the bang-bang ... bang-bang .... bang-bang sound made by wheels rolling over a rail joint ).

Freight cars ( and some passenger cars like multiple-unit cars whose traction motors do not yield room on axles to allow the placement of disk brakes ) are equipped with clasp brakes which directly grab the rolling surface of the wheels ( much like the old horse buggy brakes of yesteryear ).

They are deeply involved in the procurement of new hardware, rolling out new software installs, maintaining the disk images for new computer installs, making sure that licenses are paid for and up to date for software that need it, maintaining the standards for server installations and applications, and monitoring the performance of the network, checking for security breaches, poor data management practices.

The laser turntable uses a laser as the pickup instead of a stylus in physical contact with the disk.

In disks that rotate, the seat is always in contact with the disk, but the area of contact changes as the disc is turned.

... As the disk revolves, 80 electrically operated hammers tap the back of the paper against an inked ribbon in contact with the disk, thus printing the proper characters in the proper places on the line.

The current flowed out through the sliding spring contact m, through the external circuit, and back into the center of the disk through the axle.

When the user pressed a key on the typewriter keyboard, a small amount of current from a battery flowed through the key into one of the contacts on the input side of the disk, through the wiring, and back out a different contact.

At the end of the stack of rotors was an additional, non-rotating disk, the " reflector ," wired such that the input was connected electrically back out to another contact on the same side and thus was " reflected " back through the three-rotor stack to produce the ciphertext.

The disk must then " wobble " or nutate about the vertical axis, since the bottom and the top of the disk remain in contact with the mounting chamber.

The term " crash " may originate from the phrase " head crash ", which occurs when the read / write heads inside a hard disk physically come into contact with --" crash " into — the platter, the magnetic data storage surface of a hard disk.

Measurements commonly made on-site and in direct contact with the water source in question include temperature, pH, dissolved oxygen, conductivity, oxygen reduction potential ( ORP ), turbidity, and Secchi disk depth.

The objective of play is to use a striker disk with a flick of the finger to make contact with and move lighter object disks called carrom men, which are thus propelled into one of four corner.

Sound can be produced when the tubes or rods come in contact with a suspended central clapper in the form of a ball or horizontal disk, or with each other.

Just after second contact, and again just before third contact during the transit, a small black " teardrop " appears to connect Venus ' disk to the limb of the Sun, making it impossible to accurately time the exact moment of second or third contact.

Features mentioned in the patent paperwork included optional hot swapping, guide rails for proper electrical contact, and a method to lock the drives in place once they were secured in the disk enclosure.

A head crash is a hard-disk failure that occurs when a read – write head of a hard disk drive comes in contact with its rotating platter, resulting in permanent and usually irreparable damage to the magnetic media on the platter surface.

A tiny particle of dirt or other detritus, excessive shock or vibration, or accidentally dropping a running drive can cause a head to bounce against its disk, destroying the thin magnetic coating on the area the heads come in contact with, and often damaging the heads in the process.

These create wedge-shaped regions of oil inside the bearing between the pads and a rotating disk, which support the applied thrust and eliminate metal-on-metal contact.

The vigilante Hardware gives Virgil a new costume and modified flying disk, which enables the two to remain in contact despite living in different cities.

In addition to allowing Static to remain in contact with Hardware, the disk also displays charts and other information relevant to the mission at hand.