SMS Geier

SMS "Geier" ("His Majesty's Ship "Vulture"") was an unprotected cruiser of the built for the German Imperial Navy ("Kaiserliche Marine"). She was laid down in 1893 at the Imperial Dockyard in Wilhelmshaven, launched in October 1894, and commissioned into the fleet a year later in October 1895. Designed for service in Germany's overseas colonies, the ship required the comparatively heavy armament of eight SK L/35 guns and a long cruising radius. She had a top speed of .
"Geier" spent the majority of her career on foreign stations, including tours in the Americas, East Asia, and Africa. In 1897, she was deployed to the Caribbean, and during the Spanish–American War the following year, she ferried Europeans out of the war zone to Mexico by crossing the blockade lines around Cuban ports. After being transferred to the western coast of the Americas in 1899, "Geier" was reassigned to China to help suppress the Boxer Rebellion in 1900. She remained in East Asian waters through 1905 before being recalled to Germany for major repairs. In 1911, the ship was assigned to the colony in German East Africa, though she served little time in the area, as the Italo-Turkish War of 1911–1912 and the Balkan Wars of 1912–13 required German warships in the Mediterranean to safeguard German interests. "Geier" returned to East Africa in early 1914, but in June that month, the new light cruiser arrived, and "Geier" headed to China for second deployment there.
"Geier" was still en route to the German base in Tsingtao when war broke out in Europe in August 1914. Slipping out of still-neutral British Singapore days before Britain declared war on Germany, she crossed the central Pacific in an attempt to link up with Maximilian von Spee's East Asia Squadron. While at sea, she captured one British freighter, but did not sink her. In need of engine repairs and coal, "Geier" put into the neutral United States port at Honolulu, Hawaii, in October 1914, where she was eventually interned. After the American entrance into the war in April 1917, the US Navy seized "Geier", commissioned her as USS "Schurz", and placed her on convoy duty. She was ultimately sunk following a collision with a freighter off the coast of North Carolina, with one man killed and twelve injured. She rests at a depth of and is a popular scuba diving site.
Design.
Through the 1870s and early 1880s, Germany built two types of cruising vessels: small, fast avisos suitable for service as fleet scouts and larger, long-ranged screw corvettes capable of patrolling the German colonial empire. A pair of new cruisers was authorized under the 1886–1887 fiscal year, intended for the latter purpose. General Leo von Caprivi, the Chief of the Imperial Admiralty, sought to modernize Germany's cruiser force. The first step in the program, the two s unprotected cruisers, provided the basis for the larger .
"Geier" was long overall and had a beam of and a draft of forward. She displaced normally and up to at full load. Her propulsion system consisted of two horizontal 3-cylinder triple-expansion steam engines that drove a pair of screw propellers. Steam was provided by four coal-fired cylindrical fire-tube boilers that were ducted into a single funnel. These provided a top speed of from , and a range of approximately at . She had a crew of 9 officers and 152 enlisted men.
The ship was armed with a main battery of eight SK L/35 quick-firing (QF) guns in single pedestal mounts, supplied with 800 rounds of ammunition in total. They had a range of . Two guns were placed side by side forward, two on each broadside, and two side by side aft. The gun armament was rounded out by five Hotchkiss revolver cannon for defense against torpedo boats. She was also equipped with two torpedo tubes with five torpedoes, both of which were mounted on the deck.
Service history.
"Geier" was ordered under the contract name "F" and was laid down at the Imperial Dockyard in Wilhelmshaven in 1893. She was launched on 18 October 1894, after which fitting-out work commenced. During her launching ceremony, "Vizeadmiral" (Vice Admiral) Victor Valois christened the ship. She was commissioned into the German Navy on 24 October 1895 for sea trials. Her trials were completed on 21 January 1896, and she was decommissioned temporarily in Kiel. During construction, her design was slightly modified based on experience from her sister ships that had already completed their sea trials. "Geier"s displacement was increased slightly by around compared to the other ships of the class and her stern was modified.
First deployment abroad.
"Geier" was recommissioned on 1 December 1897 for her first deployment abroad, to the West Indies. Until then, Germany had relied on school ships to protect German nationals in the region. Rising tensions in Haiti prompted the "Admiralstab" (Admiralty Staff) to send "Geier" to the Caribbean, replacing the old ironclad that had been scheduled to deploy there. The ironclad , which had recently been rebuilt into an armored cruiser, was sent to strengthen the German naval contingent. "Geier" departed Kiel on 9 December and arrived in Charlotte Amalie in the Danish West Indies on 3 January 1898, where she rendezvoused with the school ships and . "Charlotte" and "Stein" had already taken care of the situation in Haiti, so "Geier" went to Santiago de Cuba, where she stayed from 24 March to 6 April. She then received an order to visit Brazilian and Argentinian ports; stops included Pernambuco in Brazil (16–20 April) and Bahía Blanca in Argentina (23 April). While she was in the latter port, her tour of South America was cut short due to the outbreak of the Spanish–American War.
On 6 May she arrived in Saint Thomas. She thereafter made trips to Santiago de Cuba and San Juan. While in San Juan on 13–14 May, "Geier" witnessed an American squadron under Rear Admiral William T. Sampson bombard the city. The US government permitted "Geier" to cross the blockade line outside Havana to evacuate twenty civilians of various nationalities and take them to Veracruz in Mexico, arriving on the 29th. There, the governor of the city and the artillery officer from the training ship visited "Geier" for some practice torpedo launches. While "Geier" was in Mexico, the German ambassador invited her commander and 27 men to visit Mexico City, where they were received by President Porfirio Díaz. "Geier" thereafter returned to Cuba. On 16 June, the ship called on the port of Cienfuegos in Cuba. She passed through the American blockade of Santiago de Cuba twice, on 22–29 June and 1–4 August.
After the war ended, "Geier" visited New Orleans on 14 October, departing eleven days later for the Caribbean. She then resumed her tour of South America that had been interrupted by the war. She typically stopped in ports where significant numbers of Germans had emigrated. While in Buenos Aires, she received an order to proceed to the west coast of the continent. She transited the Straits of Magellan on 20–23 February 1899 and made stops in Valparaiso, Chile, Callao, Peru, and Panama. From 11 to 17 May, she stopped in Puerto San José, Guatemala, where she met a British cruiser; the two ships were sent there to settle financial disputes with the Guatemalan government. "Geier"s tour continued, with stops in Corinto, Nicaragua, Guayaquil, Ecuador, and Puntarenas, Costa Rica. While in Corinto, she received orders to proceed further north, to the western coast of the United States and Canada. She stopped in Acapulco before arriving in San Francisco on 14 August, where she underwent a boiler overhaul. On 18 September, she departed San Francisco bound for Vancouver, stopping in Esquimalt en route. On 18 October, she left Vancouver and began her return voyage south. She visited Chilean harbors in January and February 1900, including Puerto Montt on 14 February, before turning back north, as she had been assigned to the newly created West American station.
While in Acapulco on 9 July, "Geier" was ordered to cross the Pacific to join the forces of the Eight Nation Alliance fighting the Boxer Rebellion in Qing China. She left port on 11 July for Yokohama, Japan, by way of Honolulu, Hawaii. She arrived in Chefoo on 29 August, where she joined the ships of the East Asia Squadron. "Geier" first patrolled the Bohai Sea before docking in Tsingtao at the German-held Kiautschou Bay concession in October. On 28 October, she steamed to Shanghai, where she remained until February 1901. "Geier" then steamed up the Yangtze to Chungking, where she replaced her sister ship . On 5 April, "Geier" returned to Tsingtao; on the 29th, she was transferred to the coast of central China, where she replaced another sister, . "Geier" returned to Tsingtao on 18 July, and began a tour of Korean and Japanese ports four days later with the flagship of the East Asia Squadron, . The next twelve months were filled with cruises in the region.
On 15 October 1902, "Geier" began a long cruise south to the Dutch East Indies, which also included a stop in Singapore. The ship entered the dry dock in Nagasaki, Japan, for a major overhaul on 2 March 1903, which lasted until 26 April. At this time, "Geier" was formally assigned to the East Asia Squadron. The ship resumed its normal routine of cruises in East Asian waters with stops in various ports. In February 1904, the Russo-Japanese War broke out; from April to August, "Geier" was in Chemulpo, which had been captured by the Japanese. By 1905, the ship was suffering wear, having spent over seven years on foreign stations. The repair facilities in Tsingtao were insufficient for the amount of work that needed to be done, and so "Geier" was ordered to return to Germany. She left Tsingtao on 14 January and arrived in Kiel on 16 March, where she was decommissioned for a significant period of repair work. Her three-masted schooner barque rig was reduced to a two-masted topsail schooner rig.
Second overseas deployment.
In early 1911, "Geier" was recommissioned to replace the unprotected cruiser on the East African Station, based in German East Africa. On 2 May she left Danzig, arriving in Kiel the following day. There, she was equipped for the deployment abroad. The ship left Kiel on 8 May and arrived in Dar es Salaam on 9 July, where she joined "Seeadler". She cruised the colony's coast, but at the end of September she was ordered to the Mediterranean Sea, as the Italo-Turkish War had broken out on the 29th. At the time, the only German warship in the Mediterranean was the old gunboat , the station ship in Constantinople; this was a result of the heightened tensions in Europe following the Agadir Crisis in July, as most German warships in European waters had been recalled to Germany.
"Geier"s departure for the Mediterranean was delayed by a coal fire in Dar es Salaam, which required her crew to put out. She left East Africa on 2 October and arrived in Piraeus, Greece, on 16 October, where she remained until January 1912. She was then formally assigned to the Mediterranean Division, along with the recently arrived battlecruiser . From mid-April to mid-July, she made trips to provide humanitarian assistance in Libya, Palestine, and the Red Sea. These were interrupted by the arrival of Kaiser Wilhelm II's yacht "Hohenzollern"; the two ships cruised to the island of Corfu in early May. On 17 July, "Geier" went to Trieste in Austria-Hungary for an overhaul that lasted until 30 September. She thereafter went on a cruise of the eastern Mediterranean and visited several ports.
She was loading coal in Haifa on 31 January 1913 when a coal dust explosion killed two crew members. While cruising Turkish waters in August, she was ordered to replace the light cruiser in the international naval blockade of Montenegro during the Second Balkan War. She arrived off the mouth of the Bojana River in Montenegro on 11 August and patrolled it until 14 October, when she was released for a major overhaul in Triest. After repairs were completed on 4 January 1914, she was ordered to return to the East Africa Station. She arrived there on 22 February and conducted a survey of the harbor at Tanga. On 6 May, the ship was formally reclassified as a gunboat. The light cruiser arrived on 5 June to replace "Geier", which was then reassigned to the South Seas Station, where she would in turn replace her sister .
World War I.
"Geier"s captain learned of the rising tensions in Europe following the assassination of Archduke Franz Ferdinand of Austria while en route to the Pacific. The ship coaled in Singapore on 25–29 July, departing the day after Austria-Hungary declared war on Serbia. "Geier" thereafter proceeded southeast through the Gaspar Strait, rather than north to Tsingtao, where he would be expected to go. While off Batavia on 1 August, "Geier" received the order from Maximilian von Spee, the commander of the East Asia Squadron, to join him at Yap. On 3. August, she received word of the German mobilization and the order to begin cruiser warfare. She coaled at Jampea from the steamer of the "Deutsch-Australische Dampfschiffs-Gesellschaft" (DADG) on 6 August before steaming north through the Buton Strait. Off Celebes she rendezvoused with the DADG steamer , which acted as her collier.
"Geier"s crew made temporary repairs to the ship's engines and boilers before proceeding north to the Palau Islands. "Bochum" took "Geier" under tow to conserve coal. On 20 August, she managed to contact the cruiser , which was detached from the East Asia Squadron and operating as a commerce raider. "Emden" instructed "Geier" to rendezvous at the island of Anguar, but she was unable to reach the island before "Emden" departed. Nevertheless, the two ships met at sea the following day; one of "Geier"s cutters took her commander, Lieutenant Commander Curt Graßhoff, aboard "Emden" to meet with her captain. "Emden" then departed for the Molucca Strait, while "Geier" proceeded to Anguar. After arriving, "Geier" coaled from the HAPAG steamer . Graßhoff intended to rendezvous with the East Asia Squadron in the central Pacific, and proceeded through the Bismarck Archipelago before turning north to Kusaie. There, on 4 September, "Geier" captured the British freighter "Southport" and disabled the ship's engines before departing. The freighter's crew repaired the damage, however, and "Southport" made for Australia where she reported the German gunboat's presence.
On 11 September, "Geier" arrived in Majuro, though the East Asia Squadron had already departed the island on 30 August. By this time, the ship's engines were in such bad shape that she would have been unable to reach Tsingtao, though the point was moot, as Japanese forces had already besieged the port. In addition, opportunities for commerce raiding in the area were slim, and there were no suitably fast steamers available to arm as auxiliary cruisers. Graßhoff therefore decided to follow the East Asia Squadron to South America, despite the slow speed of his ship, which was reduced to . The Norddeutscher Lloyd (NDL) steamer towed "Geier" to the Marshall Islands, where further repairs were made from 17 to 20 September. By this time, the ship's coal and water supplies were so low that the ship would not be able to continue past Hawaii. She arrived in Honolulu on 15 October, where the then-neutral Americans requested that "Geier" be interned. Two Japanese ships—the battleship "Hizen" and the armored cruiser —had been patrolling in the area. Upon learning of the arrival of "Geier", the two ships remained just outside the three mile limit to await "Geier"s departure. Graßhoff was able to delay the internment request until 7 November owing to damage to the ship and poor weather. The following day, the US Navy interned "Geier".
Service as USS "Schurz".
The United States entered the war on the side of the Allies on 6 April 1917. The US Navy seized "Geier" and refitted her for service in the Navy as a gunboat. The ship was renamed USS "Schurz" on 9 June, and commissioned on 15 September 1917, under the command of Commander Arthur Crenshaw. "Schurz" departed Pearl Harbor on 31 October and escorted Submarine Division 3 to San Diego. Arriving on 12 November, she continued on with the submarines , , , and , in early December. At the end of the month, the convoy transited the Panama Canal and proceeded to Honduras. On 4 January 1918, "Schurz" was relieved of escort duty. She carried the American consul from Puerto Cortes to Omao and back, after which she sailed for Key West. From Florida, she was transferred to New Orleans and then sailed for Charleston, South Carolina on 1 February where she entered dry dock for periodic maintenance.
Assigned to the American Patrol Detachment, "Schurz" departed Charleston toward the end of April and, for the next two months, conducted patrols and performed escort duty and towing missions along the east coast and in the Caribbean. On 19 June, she departed New York for Key West. At 04:44 on the 21st, southwest of Cape Lookout lightship, she was rammed by the merchant ship "Florida". The ship hit "Schurz" on the starboard side, crumpling that wing of the bridge, penetrating the well and berth deck about 12 feet, and cutting through bunker no. 3 to the forward fire room. One of "Schurz"s crewmen was killed instantly; twelve others were injured. "Schurz" was abandoned and sank three hours later. The ship was struck from the Navy list on 26 August 1918.
Wreck.
The wreckage rests at a depth of with the top of the wreck situated at . In 2000, the ship was the subject of a Phase II archaeological investigation headed by East Carolina University. The wreck is protected by sovereign immunity and it is therefore illegal to recover artifacts from the site without permission. In 2013, "Scuba Diving" magazine named USS "Schurz" as one of the top ten wreck dives in North Carolina.


Konica AR-mount

The Konica AR camera lens mount was introduced in 1965 with the Konica Autoreflex (Autorex in Japan market), together with a range of lenses. It features a comparably short flange focal distance of 40.50 mm for a 35 mm film SLR camera. Its diameter is 47 mm. The focus of the Konica Hexanon lenses were from 21 mm to 1000 mm; at the start one zoom 47-100mm f3.5 Hexanon AR-H was offered. Konica produced cameras for Konica AR bayonet until 1988.
For Konica-lenses with the older F-mount were adapters available.


Magnetovision

Magnetovision is the measuring technique enabling the visualization of magnetic field distribution in a given space.
Measuring setup.
Magnetovision measuring stand consists of a magnetometer, X-Y or X-Y-Z movement mechanism and data processing and visualization system.
Following modes of magnetovision signal acquisition are possible:
Magnetometers.
Typically, following types of sensors may be used:
Types.
There are different modes of magnetovision measurements. Measurements may be performed in 2D (X-Y) or 3D (X-Y-Z). Moreover, measurements of magnetic field may be absolute, differential or gradiometric.
Applications.
Magnetovision may be used for:
Data fusion.
Magnetovision images may be used for data fusion with visual signal. This creates new possibility of presentation of magnetic field distribution for further analyses.


Alexa toolbar


Magic Trackpad

The Magic Trackpad is a multi-touch trackpad produced by Apple Inc. Announced on July 27, 2010, it was 80% larger than the trackpad found on the then-current MacBook family of laptops.
A new version called the Magic Trackpad 2 came out on October 13, 2015.
Description.
The Magic Trackpad is made of glass and aluminium. The trackpad is designed in the same style as Apple's Wireless Keyboard and can sit flush to it. The entire trackpad can be used as a button. Pressing down on it puts pressure on two circular feet below to register a click. The trackpad connects via Bluetooth. The Magic Trackpad 2 is fully rechargeable using a Lightning cable.
Release and reception.
Initial reviews of the trackpad lauded its design but not its price.
Scott Stein of CNET wrote: "Apple's $69 Bluetooth device is minimalist and not particularly cheap"; "We're not sure we'd ditch our mouse and use the Magic Trackpad, but it's a compact solution for the touch-addicted."
Macworld also praised the trackpad's design similarity with the Apple Wireless Keyboard: "The Magic Trackpad is the same height and angle of inclination as the Apple Wireless Keyboard, making them a good fit, in terms of size and style."


Linear range

The linear range is that range of input or output values for which an electronic amplifier produces an output signal that is a direct, linear function of the input signal. That is, the output can be represented by the equation:
When operating in the linear range, no clipping occurs. If an amplifier were perfectly linear, no distortion (harmonic distortion or intermodulation distortion) would occur (although random noise may still be introduced).
Vacuum tube amplifiers tend to exhibit soft clipping; as they approach the maximum possible output value, the gain tends to drop, rounding the tops of the signal waveform. Transistor amplifiers, by comparison, tend to produce hard clipping; the gain remains approximately the same until the maximum possible output voltage is reached; at that point, hard clipping occurs and the waveform never exceeds that value. The sharp inflection points thus produced in the output waveform tend to have many more high-order harmonics. This is alleged to be the basis of the "transistor sound" that some audiophiles find offensive (although this would not have occurred if they would not have been driving their amplifiers beyond the linear range in the first place).


De Lisle carbine

The De Lisle carbine or De Lisle Commando carbine was a British firearm used during World War II that was designed with an integrated suppressor. That, combined with its use of subsonic ammunition, made it extremely quiet in action, possibly one of the quietest firearms ever made.
Few were manufactured as their use was limited to specialist military units.
History.
The weapon was designed as a private venture by William Godfray de Lisle (known as Godfray), an engineer who worked for the Air Ministry. He made the first prototype in .22 calibre; this he tested by shooting rabbits and other small game for the table, near his home on the Berkshire Downs. In 1943, he approached Major Sir Malcolm Campbell of Combined Operations with his prototype; this was informally tested by firing the weapon into the River Thames from the roof of the New Adelphi building in London. This was chosen to discover if people in the street below heard it firing – they did not. Combined Operations officials were impressed with the weapon and requested De Lisle produce a 9mm version. However, this was a failure. A third prototype, using the .45 ACP cartridge that was favoured by de Lisle, was much more successful. Tests of this showed the weapon had acceptable accuracy, produced no visible muzzle flash and was inaudible at a distance of .
Subsequent official firing tests recorded the De Lisle produced 85.5 dB of noise when fired. As a comparison, modern testing on a selection of handguns has shown that they produce 156 to 168 dB when firing without a suppressor, and 117 to 140 dB when firing with one fitted. The De Lisle's quietness was found to be comparable to the British Welrod pistol. However, the Welrod was useful only at very short range and used fabric and rubber components in the suppressor that required replacement after a few shots. The De Lisle was able to fire hundreds of rounds before the suppressor required disassembly for cleaning.
Combined Operations requested a small production run of De Lisle carbines and an initial batch of 17 were hand–made by Ford Dagenham, with Godfray De Lisle himself released from his Air Ministry duties so he could work full-time on the project; this initial batch was immediately put into combat use by the British Commandos. In 1944, the Sterling Armaments Company was given an order for 500 De Lisle carbines, but eventually only produced around 130. The Sterling version differed in a number of details from the earlier, Ford Dagenham model. Two prototypes of a further version, for Airborne forces, were made. These had folding stocks, similar to those fitted to the Sterling submachine gun.
During the remainder of World War II, the De Lisle carbine was mainly used by the Commandos, although they also saw some use by the Special Operations Executive (SOE). E. Michael Burke, the American former commander of a Jedburgh Team, stated that a De Lisle was used by them to assassinate two senior German officers in 1944.
A number of De Lisles were shipped to the Far East and used during the Burma Campaign. The De Lisle would also be used during the Korean War and the Malayan Emergency. It has been claimed the weapon was also used by the Special Air Service during the Northern Irish Troubles.
Description.
The De Lisle was based on a Short Magazine, Lee–Enfield Mk III* converted to .45 ACP by modifying the receiver, altering the bolt/bolthead, replacing the barrel with a modified Thompson submachine gun barrel (6 grooves, RH twist), and using modified magazines from the M1911 pistol. The primary feature of the De Lisle was its extremely effective suppressor, which made it very quiet in action. So quiet that working the bolt (to chamber the next round), makes a louder noise than firing a cartridge.
The .45 ACP cartridge was selected as its muzzle velocity is subsonic for typical barrel lengths; consequently it would both retain its full lethality and not require custom-loaded ammunition to use with a suppressor. Most rifle rounds are supersonic, where the bullet generates a "sonic boom" like any other object traveling at supersonic velocities, making them unsuitable for covert purposes. The Thompson gun barrel was "ported" (i.e. drilled with holes) to provide a controlled release of high pressure gas into the suppressor that surrounds it before the bullet leaves the barrel. The suppressor, in diameter, went all the way from the back of the barrel to well beyond the muzzle, making up half the overall length of the weapon. The suppressor provided a very large volume to contain the gases produced by firing; this was one of the keys to its effectiveness. The MP5SD and AS Val are among other modern firearms that use the same concept.
The Lee–Enfield bolt was shortened to feed the .45 ACP rounds; the Lee–Enfield's magazine set-up was replaced with a new assembly that held a modified M1911 magazine. The bolt operation offered an advantage in that the shooter could refrain from chambering the next round if absolute silence was required after firing; a semi-automatic weapon would not have offered this option as the cycling of the bolt coupled with rearward escaping propellant gas and the clink of the empty case against any hard surface would produce a noise with each shot. While the carbine was silent, it was not very accurate.
De Lisle's own .22 prototype was given to the National Army Museum in London, but it was subsequently lost and its present whereabouts are unknown. A reproduction of the .45 caliber carbine is manufactured by the American company Valkyrie Arms. Special Interest Arms for a time produced limited quantities of a De Lisle replica which incorporated an improved magazine adapter system that allows the use of unmodified M1911 magazines and also fully supports the barrel chamber in the action, later discontinued.


Zeiss A-mount


Reaction engine

A reaction engine is an engine or motor that produces thrust by expelling reaction mass, in accordance with Newton's third law of motion. This law of motion is most commonly paraphrased as: "For every action force there is an equal, but opposite, reaction force."
Examples include jet engines, rocket engines, pump-jet, and more uncommon variations such as Hall effect thrusters, ion drives, mass drivers, and nuclear pulse propulsion.
Energy use.
Propulsive efficiency.
For all reaction engines that carry on-board propellant (such as rocket engines and electric propulsion drives) some energy must go into accelerating the reaction mass. Every engine wastes some energy, but even assuming 100% efficiency, the engine needs energy amounting to
(where M is the mass of propellent expended and formula_2 is the exhaust velocity), which is simply the energy to accelerate the exhaust.
Comparing the rocket equation (which shows how much energy ends up in the final vehicle) and the above equation (which shows the total energy required) shows that even with 100% engine efficiency, certainly not all energy supplied ends up in the vehicle – some of it, indeed usually most of it, ends up as kinetic energy of the exhaust.
If the specific impulse (formula_3) is fixed, for a mission delta-v, there is a particular formula_3 that minimises the overall energy used by the rocket. This comes to an exhaust velocity of about ⅔ of the mission delta-v (see the energy computed from the rocket equation). Drives with a specific impulse that is both high and fixed such as Ion thrusters have exhaust velocities that can be enormously higher than this ideal, and thus end up powersource limited and give very low thrust. Where the vehicle performance is power limited, e.g. if solar power or nuclear power is used, then in the case of a large formula_5 the maximum acceleration is inversely proportional to it. Hence the time to reach a required delta-v is proportional to formula_5. Thus the latter should not be too large.
On the other hand, if the exhaust velocity can be made to vary so that at each instant it is equal and opposite to the vehicle velocity then the absolute minimum energy usage is achieved. When this is achieved, the exhaust stops in space and has no kinetic energy; and the propulsive efficiency is 100% all the energy ends up in the vehicle (in principle such a drive would be 100% efficient, in practice there would be thermal losses from within the drive system and residual heat in the exhaust). However, in most cases this uses an impractical quantity of propellant, but is a useful theoretical consideration.
Some drives (such as VASIMR or electrodeless plasma thruster) actually can significantly vary their exhaust velocity. This can help reduce propellant usage and improve acceleration at different stages of the flight. However the best energetic performance and acceleration is still obtained when the exhaust velocity is close to the vehicle speed. Proposed ion and plasma drives usually have exhaust velocities enormously higher than that ideal (in the case of VASIMR the lowest quoted speed is around 15 km/s compared to a mission delta-v from high Earth orbit to Mars of about 4 km/s).
For a mission, for example, when launching from or landing on a planet, the effects of gravitational attraction and any atmospheric drag must be overcome by using fuel. It is typical to combine the effects of these and other effects into an effective mission delta-v. For example, a launch mission to low Earth orbit requires about 9.3–10 km/s delta-v. These mission delta-vs are typically numerically integrated on a computer.
Cycle efficiency.
All reaction engines lose some energy, mostly as heat.
Different reaction engines have different efficiencies and losses. For example, rocket engines can be up to 60–70% energy efficient in terms of accelerating the propellant. The rest is lost as heat and thermal radiation, primarily in the exhaust.
Oberth effect.
Reaction engines are more energy efficient when they emit their reaction mass when the vehicle is travelling at high speed.
This is because the useful mechanical energy generated is simply force times distance, and when a thrust force is generated while the vehicle moves, then:
where F is the force and d is the distance moved.
Dividing by length of time of motion we get:
Hence:
where P is the useful power and v is the speed.
Hence, v should be as high as possible, and a stationary engine does no useful work.
Delta-v and propellant.
Exhausting the entire usable propellant of a spacecraft through the engines in a straight line in free space would produce a net velocity change to the vehicle; this number is termed "delta-v" (formula_10).
If the exhaust velocity is constant then the total formula_10 of a vehicle can be calculated using the rocket equation, where "M" is the mass of propellant, "P" is the mass of the payload (including the rocket structure), and formula_12 is the velocity of the rocket exhaust. This is known as the Tsiolkovsky rocket equation:
For historical reasons, as discussed above, formula_12 is sometimes written as
where formula_16 is the specific impulse of the rocket, measured in seconds, and formula_17 is the gravitational acceleration at sea level.
For a high delta-v mission, the majority of the spacecraft's mass needs to be reaction mass. Because a rocket must carry all of its reaction mass, most of the initially-expended reaction mass goes towards accelerating reaction mass rather than payload. If the rocket has a payload of mass "P", the spacecraft needs to change its velocity by formula_10, and the rocket engine has exhaust velocity "ve", then the reaction mass "M" which is needed can be calculated using the rocket equation and the formula for formula_16:
For formula_10 much smaller than "ve", this equation is roughly linear, and little reaction mass is needed. If formula_10 is comparable to "ve", then there needs to be about twice as much fuel as combined payload and structure (which includes engines, fuel tanks, and so on). Beyond this, the growth is exponential; speeds much higher than the exhaust velocity require very high ratios of fuel mass to payload and structural mass.
For a mission, for example, when launching from or landing on a planet, the effects of gravitational attraction and any atmospheric drag must be overcome by using fuel. It is typical to combine the effects of these and other effects into an effective mission delta-v. For example, a launch mission to low Earth orbit requires about 9.3–10 km/s delta-v. These mission delta-vs are typically numerically integrated on a computer.
Some effects such as Oberth effect can only be significantly utilised by high thrust engines such as rockets; i.e., engines that can produce a high g-force (thrust per unit mass, equal to delta-v per unit time).
Energy.
In the ideal case formula_23 is useful payload and formula_24 is reaction mass (this corresponds to empty tanks having no mass, etc.). The energy required can simply be computed as
This corresponds to the kinetic energy the expelled reaction mass would have at a speed equal to the exhaust speed. If the reaction mass had to be accelerated from zero speed to the exhaust speed, all energy produced would go into the reaction mass and nothing would be left for kinetic energy gain by the rocket and payload. However, if the rocket already moves and accelerates (the reaction mass is expelled in the direction opposite to the direction in which the rocket moves) less kinetic energy is added to the reaction mass. To see this, if, for example, formula_12=10 km/s and the speed of the rocket is 3 km/s, then the speed of a small amount of expended reaction mass changes from 3 km/s forwards to 7 km/s rearwards. Thus, although the energy required is 50 MJ per kg reaction mass, only 20 MJ is used for the increase in speed of the reaction mass. The remaining 30 MJ is the increase of the kinetic energy of the rocket and payload.
In general:
Thus the specific energy gain of the rocket in any small time interval is the energy gain of the rocket including the remaining fuel, divided by its mass, where the energy gain is equal to the energy produced by the fuel minus the energy gain of the reaction mass. The larger the speed of the rocket, the smaller the energy gain of the reaction mass; if the rocket speed is more than half of the exhaust speed the reaction mass even loses energy on being expelled, to the benefit of the energy gain of the rocket; the larger the speed of the rocket, the larger the energy loss of the reaction mass.
We have
where formula_29 is the specific energy of the rocket (potential plus kinetic energy) and formula_10 is a separate variable, not just the change in formula_31. In the case of using the rocket for deceleration; i.e., expelling reaction mass in the direction of the velocity, formula_31 should be taken negative.
The formula is for the ideal case again, with no energy lost on heat, etc. The latter causes a reduction of thrust, so it is a disadvantage even when the objective is to lose energy (deceleration).
If the energy is produced by the mass itself, as in a chemical rocket, the fuel value has to be formula_33, where for the fuel value also the mass of the oxidizer has to be taken into account. A typical value is formula_34 = 4.5 km/s, corresponding to a fuel value of 10.1MJ/kg. The actual fuel value is higher, but much of the energy is lost as waste heat in the exhaust that the nozzle was unable to extract.
The required energy formula_35 is
Conclusions:
These results apply for a fixed exhaust speed.
Due to the Oberth effect and starting from a nonzero speed, the required potential energy needed from the propellant may be "less" than the increase in energy in the vehicle and payload. This can be the case when the reaction mass has a lower speed after being expelled than before – rockets are able to liberate some or all of the initial kinetic energy of the propellant.
Also, for a given objective such as moving from one orbit to another, the required formula_10 may depend greatly on the rate at which the engine can produce formula_10 and maneuvers may even be impossible if that rate is too low. For example, a launch to Low Earth orbit (LEO) normally requires a formula_10 of ca. 9.5 km/s (mostly for the speed to be acquired), but if the engine could produce formula_10 at a rate of only slightly more than "g", it would be a slow launch requiring altogether a very large formula_10 (think of hovering without making any progress in speed or altitude, it would cost a formula_10 of 9.8 m/s each second). If the possible rate is only formula_48 or less, the maneuver can not be carried out at all with this engine.
The power is given by
where formula_50 is the thrust and formula_51 the acceleration due to it. Thus the theoretically possible thrust per unit power is 2 divided by the specific impulse in m/s. The thrust efficiency is the actual thrust as percentage of this.
If, e.g., solar power is used, this restricts formula_51; in the case of a large formula_34 the possible acceleration is inversely proportional to it, hence the time to reach a required delta-v is proportional to formula_34; with 100% efficiency:
Examples:
Thus formula_34 should not be too large.
Power to thrust ratio.
The power to thrust ratio is simply:
Thus for any vehicle power P, the thrust that may be provided is:
Example.
Suppose a 10,000 kg space probe will be sent to Mars. The required formula_10 from LEO is approximately 3000 m/s, using a Hohmann transfer orbit. For the sake of argument, assume the following thrusters are options to be used:
Observe that the more fuel-efficient engines can use far less fuel; their mass is almost negligible (relative to the mass of the payload and the engine itself) for some of the engines. However, these require a large total amount of energy. For Earth launch, engines require a thrust to weight ratio of more than one. To do this with the ion or more theoretical electrical drives, the engine would have to be supplied with one to several gigawatts of power, equivalent to a major metropolitan generating station. From the table it can be seen that this is clearly impractical with current power sources.
Alternative approaches include some forms of laser propulsion, where the reaction mass does not provide the energy required to accelerate it, with the energy instead being provided from an external laser or other beam-powered propulsion system. Small models of some of these concepts have flown, although the engineering problems are complex and the ground-based power systems are not a solved problem.
Instead, a much smaller, less powerful generator may be included which will take much longer to generate the total energy needed. This lower power is only sufficient to accelerate a tiny amount of fuel per second, and would be insufficient for launching from Earth. However, over long periods in orbit where there is no friction, the velocity will be finally achieved. For example, it took the SMART-1 more than a year to reach the Moon, whereas with a chemical rocket it takes a few days. Because the ion drive needs much less fuel, the total launched mass is usually lower, which typically results in a lower overall cost, but the journey takes longer.
Mission planning therefore frequently involves adjusting and choosing the propulsion system so as to minimise the total cost of the project, and can involve trading off launch costs and mission duration against payload fraction.


Zulaica Automatic Revolver

The Zulaica Automatic Revolver is an automatic revolver of Spanish origin. It was produced for a very short time. The weapon was fed from a 6 round cylinder and chambered in the .22 LR round.
Overview.
M. Zulaica y Cia., Eibar, Spain. began manufacturing 'Velo-Dog' type pocket revolvers in the early 1900s. In 1905, Zulaica patented an unusual automatic revolver design, but few were ever manufactured and even fewer have survived.


Pass through device (automotive)

A passthrough device is used in conjunction with a computer to reprogram vehicle control modules through the OBD-II/CANbus port. Each manufacturer has their own type, but SAE International standardized the J-2534 universal requirements in 2004, requiring all manufacturers to allow vehicles sold in the United States of America and Europe to accept powertrain reprogramming through specific universal parameters.


MS Athina B

The Athina B was a merchant ship. On 21 January 1980 she suffered engine failure in bad weather and beached at the English seaside resort of Brighton, to the east of the town's Palace Pier. The ship was a temporary tourist attraction, with the Volk's Electric Railway opening out of season to cash in on the large number of sightseers. The anchor of the ship is on display on Brighton seafront. A restaurant in Brighton bears the name of the ship and a painting of "Athena B" by Dennis Roxby Bott is in Brighton Museum.
Career.
Built as the "Kojima Maru" at Hiroshima in 1968, she initially sailed under the Japanese flag. She was renamed "Hung Wei" in 1973 and "Nina Pa" in 1976, before being sold and renamed the "Athina B" in 1979, sailing under the Greek flag.
Final voyage.
The "Athina B" left the Azores on 11 December 1979 laden with 3,000 tonnes of pumice. Her destination was the port at Shoreham-by-Sea, West Sussex. During the voyage, she had problems with her generator, gyro compass and radar, and put in at La Rochelle in France for repairs. On arrival at Shoreham on 20 January, force seven or eight winds meant she was unable to enter harbour. Her engines failed, and a Mayday call was issued. The Shoreham lifeboat "Dorothy and Philip Constance" took off half the crew and the captain's family, with the rest being rescued on the morning of 21 January. Four missions were needed to rescue all those on board. The ship drifted eastwards and eventually ran aground to the east of the Palace Pier. The ship broke her back and was declared a write-off.
Awards.
Coxwain Ken Voice was awarded a RNLI Silver Medal; Crew members Ken Everard, Michael Fox, Peter Huxtable, John Landale, Jack Silverson and Geoff Tugwell were awarded the RNLI's Thanks of the Institution on Vellum; Crew members Peter Everard and Derek Silverson received letters of thanks signed by the director of the RNLI for their part in the rescue of the crew of the "Athina B".
Salvage.
The ship remained on the beach for a month, guarded by the police to prevent looting. After a mobile crane was used to remove the cargo, she was refloated and towed to a scrapyard at Rainham, Kent on 21 February 1980, where she was scrapped.


Air Proving Ground Command

The Army Air Forces Proving Ground Command (AAF PGC) was the primary testing command of the United States Army Air Forces (1946-47), and then the United States Air Force (1947-57).
In March 1946, the Army Air Forces Center was redesignated the AAF PGC, adding the responsibilities of a similarly named organization in June, when it moved to Eglin Field, Florida. It became the Army Air Forces' (later the United States Air Force's) primary testing command (except for a brief period in 1948, when it was part of Air Materiel Command) until 1957. In 1957 the PGC was redesignated the Air Proving Ground Center and re-assigned to Air Research and Development Command (ARDC). The APGC continued its mission thereafter as part of the ARDC.
From 27 October 1942, the School of Applied Tactics, later the AAF Tactical Center and then the AAF Center, was stationed at Orlando Army Air Base, Florida. The Centre was redesignated the AAF PGC on 8 March 1946 and, the same day, re-stationed to
Eglin Field (later Air Force Base), Florida. It remained at Eglin AFB thereafter.
On 1 October 1998, the Air Force Development Test Center, as it had become, was redesignated the Air Armament Center. The Air Armament Center continued to carry out its tasks until it was inactivated on 1 October 2012.


Allan Wells

Allan Wipper Wells (born 3 May 1952) is a former British track and field sprinter who became the 100 metres Olympic champion at the 1980 Summer Olympics in Moscow. Within a fortnight of that, he also took on and beat America's best sprinters at an invitational meeting in Koblenz. In 1981, Wells was both the IAAF Golden Sprints and IAAF World Cup gold medallist. He is also a three-time European Cup gold medallist among many other sprint successes.
He was a multiple medallist for his native Scotland at the Commonwealth Games, winning two golds at the 1978 Commonwealth Games and completing a 100 metres/200 metres sprint double at the 1982 Commonwealth Games. Wells also recorded the fastest British 100/200 times in 1978, 1979, 1980, 1981, 1982, 1983 and 100 m in 1984.
Biography.
Early years and long jump.
Born in Edinburgh, Wells was educated at Fernieside Primary School and then Liberton High School. He left school at age 15 to begin an engineering apprenticeship. Wells was initially a triple jumper and long jumper and crowned Scottish indoor long jump champion in 1974.
Commonwealth and European sprint titles.
He began concentrating on sprint events in 1976. In 1977 he won the AAA's Indoor 60 metres title, and won his first of seven outdoor Scottish sprint titles.
In the 1978 season his times and victories continued to improve, he clocked a new British record at Gateshead 10.29, beating Don Quarrie and James Sanford, he also won the UK 100/200 Championships. At the Commonwealth Games in Edmonton, Alberta, Canada, he won the gold medal in the 200 m and silver in the 100 m. He also won the 4 × 100 m running the first leg with Drew McMaster, David Jenkins and Cameron Sharp running the other three legs.
This success continued in 1979, when he won the European Cup 200 metres in Turin, Italy, beating the new World record holder Pietro Mennea on his home ground; he also finished 3rd in the 100 metres.
Wells also beat Houston Mcteer in the 100m at Gateshead.
1980 – Olympic success and the showdown in Koblenz.
At the start of the 1980 season, Wells won the AAA's 100 metres, then went to the Côte d'Azur to finish preparing for the 1980 Moscow Olympic Games. Wells never used starting blocks, until a rule change forced him to do so for the Moscow Olympics. Prior to the Olympics he was put under pressure by Margaret Thatcher in the boycott of the games led by the Americans. Wells responded by declining all media requests. His Olympic participation was threatened by chronic back pain that arrived 2½ weeks before the games began. Each day he underwent four exhausting treatment sessions each day that left him too tired to train. Instead when not undergoing treatment he spent his time relaxing.
In Moscow, 28-year-old Wells qualified for the final, with a new British record 10.11 s, where he faced pre-race favourite Silvio Leonard of Cuba. By 60 metres the field were fading, and by 80 metres the race was between Leonard on the inside and Wells on the outside. Wells edged ahead, but Leonard drew even again. With seven metres to go Wells began an extreme lean which allowed his head and shoulder to cross the finish line before Leonard's chest in a photo finish; both men were given a final time of 10.25 s. Wells became the oldest Olympic 100 m champion at that time at the age of 28 years 83 days. He remains the last white male athlete to win the Olympic 100 metres title.
The 200 m final was another close affair. Wells from lane 7, exploded out of the blocks and ran a spectacular turn making up the stagger on Mennea to his outside after only 50 metres. Coming out of the turn he had a two-metre lead over Leonard, with Quarrie close behind in third while Mennea looking fully eclipsed. But Mennea shifted gears in the straight and caught Wells with 10 metres to go. Wells attempted a final dip which had brought him victory in the 100, but he fell short, and Wells won the silver medal behind Pietro Mennea, who beat him by 0.02 s; again he set a British record of 20.21 s. He went on to break a third British record, 38.62 s, with the sprint relay team that finished fourth in the final.
In a later interview Wells said the two issues he faced prior to the games inadvertently were key factors in his success. He said in an interview to "The Scotsman", "When we got to Moscow, [my wife and coach] Margot and I decided that I'd do six starts and see how it went. The fourth and fifth were full-out as if I was competing and I asked Margot what she thought: she said they were the best she'd ever seen me do. The rest had done me a lot of good, I was really fresh and committed, and those starts gave me the psychological edge over everyone else, which was key because the Olympics is all about your mental aptitude. You're at your fastest when you're relaxed and flowing (Wells' 10.11secs to qualify for the 100m final remains the Scottish record) rather than having to be aggressive."
Following the Moscow Olympics, there was some suggestion that Wells's gold medal had been devalued by the boycott of the games. Wells accepted an invitation to take on the best USA sprinters of the day, among others, at a track meeting in Koblenz in West Germany. Less than two weeks after the Moscow gold, Wells (10.19) won the final in Koblenz beating Americans Stanley Floyd (10.21), Mel Lattany (10.25), Carl Lewis (10.30) and Harvey Glance (10.31). Lattany went straight over to Wells after crossing the line to say, "For what it's worth, Allan, You're the Olympic champion and you would have been Olympic champion no matter who you ran against in Moscow."
At the end of 1980, Wells was awarded Scottish Sports Personality of the Year.
1981 World Cup win.
In 1981, after a successful tour of Australia and New Zealand, Wells won the European Cup 100 metres, beating East German Frank Emmelmann. Wells also finished 2nd in the 200.
He then demonstrated his calibre by finishing first in the "IAAF Golden sprints" in Berlin; which was the most prominent Sprint Meeting in the World that year. Although finishing second to the Frenchman Hermann Panzo by 0.01 secs in the 100, Wells emphatically won the 200 beating the top four American sprinters Mel Lattany, Jeff Phillips, Stanley Floyd, Steve Williams as well as Canada's Ben Johnson in the 100/200, 10.15/20.15 (200 wind assist) for Wells to win the event in an aggregate 30.30.
To add to this, Wells won the 100 metres at the IAAF World cup in Rome, beating the American Champion and world's fastest 100 m performer of the year which was 10.00 by Carl Lewis; Wells then finished 2nd in the world cup 200.
Afterwards, he beat the top Americans Mel Lattany and Stanley Floyd again, when he won a 200 in the Memorial Van Damme meeting in Brussels, Belgium.
Later sprinting career.
In 1982, in Brisbane, Queensland, Australia, Wells won two more Commonwealth titles in the 100 m, a wind assisted 10.02. and then the 200 m, and a bronze medal in the relay. He shared the 200 m title with Mike McFarlane of England in a rare dead heat.
In 1983, he won his 3rd European Cup title by winning the 200 metres, beating his old adversary Pietro Mennea in London, and again took 2nd in the 100.
He then went on and finished 4th in both the 100/200 sprint finals at the IAAF World Championships in Helsinki.
He reached the 100 m semi-finals at the 1984 Los Angeles Olympics, and was a member of the relay team that finished 7th in the final.
Wells missed most of 1985 with injury. He was not selected for the Commonwealth Games in Edinburgh in 1986, as he had failed to compete at the Scottish trials. However, in a stunning comeback, he soundly beat both Johnson and Mahorn, the respective Commonwealth 100 m and 200 m champions at Gateshead.
Wells gained additional attention at Gateshead for being the first to be seen sporting the now common Lycra running shorts. The sight of these led to him being dubbed Wilson of the Wizard (a comic book character).
Wells was consequently selected for Stuttgart in the European championships, coming fifth in both the 100 m and 200 m finals. To add to this, he also had a victory against Linford Christie at Crystal Palace at the end of 1986. One of his last victories was winning the Inverness Highland Games 100/200 double in 1987.
Wells's later career was punctuated by injury, but, by competing into his mid-30s, he helped to set the trend for sprinters to have longer careers.
After competitive retirement.
After retirement, he was a coach for the British bobsleigh team. His wife Margot Wells was also a Scottish 100/100 hurdles champion, and they are now based in Guildford, Surrey where she is a fitness consultant, and Allan is a retired systems engineer. Wells was also inducted alongside Eric Liddell and Wyndham Halswelle (two other former Scottish Athletic Olympic Champions) into the Scottish Sports Hall of Fame. Allan currently coaches the Bank of Scotland specialist sprint squad alongside another former Scottish sprinter, Ian Mackie.
Wells's personal best for the 100 metres is 10.11, and for the 200 metres is 20.21, run at the Moscow 1980 games, and both are still Scottish records.
Wells was the first baton holder for the Queen's Baton Relay for the 2014 Commonwealth Games, carrying the baton from Buckingham Palace in London.
In July 2014, Allan Wells received, along with his wife Margot, an Honorary Doctorate of Science from Edinburgh Napier University.
In June 2015, a BBC documentary (Panorama: "Catch Me If You Can") uncovered allegations by Wells' former teammate of historical doping by the 1980 Olympic 100m champion, beginning in 1977. Allan Wells forcefully denies the allegations.


Austin J. Tobin

Austin Joseph Tobin (May 25, 1903 – February 8, 1978) was an American businessman who served as the executive director of the Port of New York Authority, the precursor to the Port Authority of New York and New Jersey, from 1942 until 1972.
Tobin is widely known for authorizing the construction of the original World Trade Center, which was destroyed during the September 11 attacks in 2001.
Background.
Tobin was born on May 25, 1903, to an Irish-American family in Brooklyn, New York City. He was educated at the College of the Holy Cross and Fordham Law School.
Tobin joined the Port Authority in 1927, where he served the first 15 years of his career in the law department. He started out as a law clerk, and was promoted to assistant general counsel in 1935. In 1942, he was appointed as executive director of the Port Authority. During his thirty years as executive director, the agency gained control of LaGuardia Airport, Idlewild (later renamed John F. Kennedy International Airport), and Newark Airport. He oversaw the development of the original World Trade Center, the creation of the Lincoln Tunnel, and the Port Authority Bus Terminal. When Mr. Tobin joined the agency as a law clerk it had 300 employees. When he retired as executive director in 1972, the agency had 8,000 employees and an investment of $2.6‐billion in bridges, airports, ship terminals and other facilities, including the vast World Trade Center.
Tobin is noted for his difference of style from Robert Moses. Most particularly, for his relocation of bus terminal tenants. Furthermore, Tobin is also noted for prioritizing mass transit more so than Robert Moses.
In 1966, Tobin received The Hundred Year Association of New York's Gold Medal Award "in recognition of outstanding contributions to the City of New York."
He died on February 8, 1978, in Manhattan, New York City, at the age of 74.
Legacy.
In 1978, the Port Authority decided to rename the outdoor plaza at the World Trade Center, in his honor, as the Austin J. Tobin Plaza. The centerpiece of the plaza was "The Sphere", a 25-foot tall bronze sculpture designed by Fritz Koenig.
The plaza was destroyed during the September 11 attacks in 2001. The National September 11 Memorial now occupies the site.


TOZ rifle

TOZ rifles are a family of .22 Long Rifle bolt-action cadet rifles manufactured by the Tula Arms Plant (Russian abbreviation TOZ stands for "Tulsky Oruzheyny Zavod"). Most notably the TOZ-8, TOZ-17 and TOZ-78 which were used to train generations of Russian military, paramilitary and police cadets.
TOZ-8.
The TOZ-1 is a single-shot .22LR, bolt action cadet rifle designed in 1927 by V. Selivanov and Ya. Kanevsky. The TOZ-1s were made from the late 1920s to early 1930s, until it was replaced with the improved TOZ-8 rifles.
The TOZ-8 is a single shot .22LR bolt action cadet rifle conceived in 1932 by the designer-gunsmith D. M. Kochetov and serially produced at the Tula Arms Plant. The TOZ-8 is a simple device, trouble-free and reliable in operation. It was widely used for primary education in the school shooting, gunsmith and DOSAAF paramilitary organization in the USSR for decades. About one million TOZ-8s were made from the early 1930s to the late 1950s. Many TOZ-8 rifles are currently in civilian circulation and it is still used for hunting small game.
The receiver contains the bolt and trigger mechanism. The rifle uses bolt action: a rotating bolt locks the cartridge in the chamber, closes bore, ignites the cartridge, and ejects the spent cartridge. Lugs are missing; locking is performed on the charging handle. When the trigger is pressed, the hammer falls. The trigger is affixed to the rear end of the trigger springs from below. When pressing the trigger rests its ledges in the receiver and move down the release spring high neck than releases the trigger, which, along with hammer, moves forward under the influence of spring and drives the firing pin into the primer, igniting the cartridge and firing the shot.
There is no magazine. In place of the magazine guide is a special guide that controls the motion of the cartridge when it is rammed into the chamber. Sights include front and rear open sights. A cover protects the operator from hot gas in the event of case failure during firing (see ). The stock connects all parts of the rifle and serves for convenience when shooting; it has a butt, neck, and forearm.
TOZ-17.
The TOZ-17 is a .22 LR, bolt-action repeating rifle with a 5-round detachable magazine. It was designed in 1956. It has a similar appearance, sights and functions much the same as the Mosin–Nagant rifle. It intended for professional and amateur hunting and sport shooting.
The design reflects Soviet tradition,as it is very simple to use yet strong and functional. The rifle is very well built, reliable and accurate. It features twin extractors on the bolt which makes case ejection very positive. The bolt is considered large compared with most rimfire designs, paired with a large firing pin and spring assembly. The TOZ-17 has the bolt with a rear safety similar to BSA rifle as the BSA Sportsman.
The TOZ-17 has a free-floating barrel for increased accuracy. Its bore is anodized to reduce wear and increase barrel life. The TOZ-18 is the same rifle redesigned to accept a 2.5-power fixed focus scope. Its receiver has a standard dovetail rail for allowing a scope, but requires high rings to allow the scope to clear the rear sight.
TOZ-78.
The TOZ-78 is a .22 LR, bolt-action repeating rifle. It uses 5- and 10 round detachable magazines. The TOZ-78 was designed in 1986 and is still in production. It is based on the TOZ-17 and comes in various improved models. The TOZ-78-04 has a thread barrel to attach a suppressor. The TOZ-78-05 is a heavy barrel version designed to be used with a 2.5-power fixed focus scope. This model does not have iron sights. The TOZ-78-06 - heavy barrel version, with a thread barrel.


Bus-holder

A bus-holder (or Bus-keeper) is a weak latch circuit which holds last value on a tri-state bus.
The circuit is basically a delay element with the output connected back to the input through a relatively high impedance. This is usually achieved with two inverters connected back to back. The resistor drives the bus weakly; therefore other circuits can override the value of the bus when they are not in tri-state mode.
Bus-holders are used to prevent CMOS gate inputs from getting floating values when they are connected to tri-stated nets. Otherwise both transistors in the gate could get turned on, thus shorting the power supply and ground, which would destroy the CMOS gate. This is prevented by the bus-holder pulling the input to the last valid logic level (0 or 1) on the net. The circuit is usually placed in parallel with the tri-stated net.


The High in the Sky Seuss Trolley Train Ride


Open Core Protocol

The Open Core Protocol (OCP) is a protocol for on-chip subsystem communications.
It is an openly licensed, core-centric protocol and defines a bus-independent, configurable interface. OCP International Partnership (OCP-IP) produces OCP specifications. OCP data transfer models range from simple request-grant handshaking through pipelined request-response to complex out-of-order operations.
Legacy IP cores can be adapted to OCP, while new implementations may take advantage of advanced features: designers select only those features and signals encompassing a core’s specific data, control and test configuration.
The Open Core Protocol (OCP) is one of several FPGA processor interconnects used to connect soft FPGA peripherals to FPGA CPUs --
both soft microprocessor and hard-macro processor.
Other such interconnects include
Advanced eXtensible Interface (AXI),
Avalon,
and the Wishbone bus.
FPGA vendor Altera joined the Open Core Protocol International Partnership in 2010.


Vertical loop

The generic roller coaster vertical loop, where a section of track causes the riders to complete a 360 degree turn, is the most basic of roller coaster inversions. At the top of the loop, riders are completely inverted.
History.
The vertical loop is not a recent roller coaster innovation. Its origins can be traced back to the 1850s when "centrifugal railways" were built in France and Great Britain. The rides relied on centripetal forces to hold the car in the loop. One early looping coaster was shut down after an accident.
Later attempts to build a looping roller coaster were carried out during the late 19th century with the "Flip Flap Railway" at Sea Lion Park. The ride was designed with a completely circular loop (rather than the teardrop shape used by many modern looping roller coasters), and caused neck injuries due to the intense G-forces pulled with the tight radius of the loop.
The next attempt at building a looping roller coaster was in 1901 when Edwin Prescott built the "Loop the Loop" at Coney Island. This ride used the modern teardrop-shaped loop and a steel structure, however more people wanted to watch the attraction, rather than ride. Vertical loops weren't attempted again until the design of Great American Revolution at Six Flags Magic Mountain, which opened in 1976. Its success depended largely on its clothoid-based (rather than circular) loop. The loop became a phenomenon, and many parks hastened to build roller coasters featuring them.
In 2000, a modern looping wooden roller coaster was built, the Son of Beast at Kings Island. Although the ride itself was made of wood, the loop was supported with steel structure. Due to maintenance issues however, the loop was removed at the end of the 2006 season. The loop was not the cause of the ride's issues, but was removed as a precautionary measure. It is the only successful installation of a loop on a wooden roller coaster. Due to an unrelated issue in 2009, Son of Beast was closed until 2012, when King's Island announced that it would be removed.
On June 22, 2013, Six Flags Magic Mountain introduced Full Throttle, a steel launch coaster with a loop, the tallest in the world at the time of its opening. , the largest vertical loop is located on Flash, a roller coaster produced by Mack Rides at Lewa Adventure in Shaanxi, China. The record is shared by Hyper Coaster in Turkey's Land of Legends theme park, built in 2018, which is identical to Flash at Lewa Adventure.
Loops on non-roller coasters.
In 2002, the Swiss company Klarer Freizeitanlagen AG begun working on a safe design for a looping water slide. Since then, multiple installations of the slide, named the AquaLoop and constructed by companies including Polin, Klarer, Aquarena and WhiteWater West, have appeared in many parks. This ride does not feature a vertical loop, instead using an inclined loop (a vertical loop tilted at an angle), which puts less force on the rider. AquaLoop slides feature a safety hatch, which can be opened by a rider in case they do not reach the highest point of the looping.
Physics/Mechanics.
Most roller coaster loops are not circular in shape. A commonly used shape is the clothoid loop, which resembles an inverted tear drop and allows for less intense G-forces throughout the element for the rider. The use of this shape was pioneered in 1976 on The New Revolution at Six Flags Magic Mountain, by Werner Stengel of leading coaster engineering firm Ing.-Büro Stengel GmbH.
On the way up, from the bottom to the top of the loop, gravity is in opposition to the direction of the cars and will slow the train. The train is slowest at the top of the loop. Once beyond the top, gravity helps to pull the cars down around the bend. If the loop's curvature is constant, the rider is subjected to the greatest force at the bottom. If the curvature of the track changes suddenly, as from level to a circular loop, the greatest force is imposed almost instantly (see jerk). Gradual changes in curvature, as in the clothoid, reduce the force maximum (permitting more speed) and allow the rider time to cope safely with the changing force.
Obviously this "gentling" runs somewhat contrary to the coaster's "raison d'être". Schwarzkopf-designed roller coasters often feature near-circular loops (in case of Thriller even without any reduction of curvature between two almost perfectly circular loops) resulting in intense rides—a trademark for the designer.
It is rare for a roller coaster to stall in a vertical loop, although this has happened before. The Psyké Underground coaster (then known as Sirocco) at Walibi Belgium once stranded riders upside-down for several hours. The design of the trains and the rider restraint system (in this case, a simple lap bar) prevented any injuries from occurring, and the riders were removed with the use of a cherry picker. A similar incident occurred on Demon at Six Flags Great America.


Charles Perry McCormick

Charles Perry McCormick (June 9, 1896 - June 16, 1970) was an American businessman and civic leader active in Baltimore, Maryland. At age 36, he became president of McCormick & Company, which he led for 23 years, building it into an international spices and flavorings company. He became known for his progressive Multiple Management system and for his civic involvement in the city of Baltimore and the state of Maryland at large.
Biography.
Born in Morelia, Mexico in 1896, McCormick was the son of the Baptist missionary Hugh Pendleton McCormick and Anne Pauline (Perry) McCormick. He lived with his family in Mexico, Puerto Rico, Birmingham, Alabama, Paris and back in the States in Baltimore. After regular education in those places, he finished his secondary schooling in the Class of 1915 at The Baltimore City College, an all-boys institution, the nation's third oldest public high school, founded 1839, and then located in its second building on the site at North Howard and West Centre Streets. He later graduated from The Johns Hopkins University in 1919. then in its first years at its new campus at Homewood in north Baltimore.
After graduation, McCormick started a regular four year apprenticeship in a factory and offices of McCormick & Company, his uncle's spice firm. McCormick had already earlier started part-time in the summer of 1912 as shipping department clerk. After gaining sales experience in the Middle West and Pacific Coast section, McCormick was appointed head of the import-export department in Baltimore. In 1928 he was promoted vice president in 1928, and after the death of his uncle Willoughby M. McCormick in 1932, he was elected president of McCormick & Company. McCormick retired in 1969 and was named Chairman Emeritus.
McCormick participated in a series of business and civic affairs. He was member of the board of the Federal Reserve Bank of Richmond in 1939 and its chairman in 1952; chairman of the Board of Regents of the University of Maryland; director of several banks in and around Baltimore; and National Councilor to the Chamber of Commerce of the United States.
In 1960, McCormick was awarded the 1960 Henry Laurence Gantt Medal by the American Management Association and the ASME. Robert G. Hess, chairman of the Gantt Medal Board of Award, gave a presentation, that the award was offered him for being "a dynamic leader in business; a successful practitioner of modern principles of scientific management and valuable contributor of accepted improvements to the management profession, encompassing the humanities without sacrifice of profitable corporate performance and in addition, to influential leadership in the local community and national affairs." President and General Manager, Wright Machinery Company, Division of Sperry Rand Corporation, and will make the presentation.
He was also selected for the Alumni Hall of Fame for his high school, The Baltimore City College.
Early life.
Charles Perry McCormick was born on June 9, 1896, in Morelia, Mexico. The son of Baptist missionary Reverend Hugh Pendleton McCormick and Anne Pauline McCormick (née Perry), he had two older siblings, Catherine (Katie) and Hugh. Following his peripatetic father, he attended primary school in Puerto Rico (where his father founded the University of Puerto Rico); grammar school in Birmingham, Alabama, and Boston, Massachusetts; and high school in Paris, France; Hamilton, Virginia; and Baltimore, Maryland. He matriculated to Baltimore's Johns Hopkins University in 1916, but his studies were interrupted by the Great War.
Naval career.
McCormick enlisted in the United States Navy on April 6, 1917. He served aboard the "U.S.S. W. A. Edwards" and the "U.S.S. Edgar F. Luckenbach". He also served as Naval Athletic Director, Fifth Naval District, for nine months.
Return to Baltimore.
After his short naval career, McCormick returned to Johns Hopkins in 1919 to complete his education. Upon graduation, he went to work full-time for his uncle Willoughby M. McCormick's business, McCormick & Co., where he had already worked summers as a high school and a college student.
Background.
McCormick and Co. was founded in 1889 by Willoughby M. McCormick. The elder McCormick is said to have run the company with an "iron hand" and during the Great Depression he cut salaries across the board, first by 25%, then a further 10%. Upon his sudden death in 1932, the company's directors tapped 36-year-old Charles McCormick to replace his uncle.
Career.
The younger McCormick worked his way from hauling crates to vice president. Along the way he had moved up to sales, to supervising four sales offices, to opening the West Coast markets. (According to "The American Weekly", McCormick disliked the "too-dingy or too-shiny reception rooms" he often waited in during his years traveling for McCormick & Co. Later, after becoming president of the firm, he remade the seventh floor of McCormick's factory building into a replica of an Elizabethan English village street, including a teahouse where tea would be served to guests.)
Upon being named president of McCormick & Co., Charles McCormick promptly raised salaries 10%, cut the work week from 56 hours to 45, and solicited suggestions for improvements. These actions raised morale and brought McCormick & Co. into the black for the first time in four years. He would soon transform the company's top-down organizational structure with a plan he called Multiple Management.
Multiple Management.
Multiple Management was a profit-sharing plan designed as a way to develop and promote leaders from within the organization, as well as to solicit input from a wider cross-section of employees. "The American Weekly" called it a "most extraordinary industrial democracy". A junior board made of young executives, a factory board made of foremen and section heads, and a board of salesmen would propose recommendations to improve materials, packaging, processes, and sales and advertising. These would be reviewed by a senior board, who approved the vast majority of the proposals. A joint Combined Board would facilitate communication among all the other boards.
Under Multiple Management, more than 7,000 suggestions were sent from the junior board to the senior board between 1932 and 1948. Suggestions ranged from new bottles and tins, "snappier" labels, and improvements in machinery, inventory, and quality control. In that time, sales rose from US$3.25 million to US$26 million, and by 1935 McCormick was the largest spice and flavoring-extract business in the U.S. By 1962, net sales amounted to US$50 million yearly.
McCormick collated his ideas in two books: "Multiple Management" in 1937, and a follow-up, "Power of People", in 1949. He wrote:"Too many bankers and industrialists associate with their own clique exclusively; too many labor men travel only with their fellows. There's nothing wrong with capitalism, but there's a lot wrong with some of the people who use it. American living is the best the world has ever seen. But of what lasting use will it be if we do not learn how to get along better with one another?"That same year, "Business Week" reported: "To this date, more than 500 companies in 46 countries have made inquiries or adopted the MM plan."
Retirement.
McCormick retired as president of McCormick & Co. in 1955. He stayed on as chairman of the company until August 1969.
Civic Engagement.
McCormick was very active in civil life, serving on dozens of boards and volunteer organizations. In a dryly appreciative biographical sketch subtitled "Man With A Mission" in "Baltimore" magazine, G. H. Pouder wrote, "Charles Perry McCormick believes that achievement comes only with serving and for that reason has tackled an appalling list of jobs for the public good, which can only be described as headaches of the first water." Similarly, his obituary in "The Evening Sun" began, "It took 69 lines of type in Who's Who to list Charles P. McCormick's memberships, awards and attainments and only the more important ones at that."
Among his more notable accomplishments, he was selected to represent U.S. management at the conference of the International Labor Organization in Geneva, Switzerland from 1949 to 1952; he was also vice chairman of the conference in 1955. He also served as chairman of the Civic Center Commission of Baltimore. He was appointed a member of the Board of Regents of the University of Maryland under three consecutive governors from 1948–1966. A lover of football, he was one of the businessmen who helped establish the Baltimore Colts and served as Chairman of the first Colts Football Club, and he set up an annual award to the "Unsung Hero" of Maryland interscholastic football.
Personal life.
McCormick married Marion Andrews Hinds on October 14, 1921. They had two children, Rosalie Anne and Charles Perry, Jr. They divorced in November 1943, and later that month, on November 27, McCormick married Anne Wollman McPhail in New York. They had two more children, John Grayson and Robert Newton. At the time of his death he was survived by seven grandchildren.
McCormick painted seascapes, drew his own Christmas cards, and carved wooden statuettes as gifts.
Death.
On June 14, 1970, McCormick suffered a heart attack and was taken to University Hospital in Baltimore. He died on June 16, 1970 at 5 P.M.
In an appreciation, "The Evening Sun" wrote:"The stories such a man leaves behind are many and, again and again, favorable. The tycoon who genuinely wanted to be called by his first name, by anybody: who likes for his executives to live in the same uniform housing district; who in the old Baltimore tradition wasn't afraid to list his uptown apartment and his Sherwood Forest place in the phone book - this was a man who bartered in teas, spices and humanity, whom lived his ideals to the full by his word and even more abundantly, by his example."


Amber Sky

AmberSky Gdańsk is a 50-meter tall Ferris wheel in Gdańsk. It opened to the public on June 2016. It changed locations and reopened to the public on December 1, 2018. It is different from the Ferris wheel owned by Oscar Bruch from Germany that operated seasonally in Gdańsk before AmberSky's construction.
Design.
The Netherlands-based Dutch Wheels designed and constructed the wheel. It is a model R50SP-36. It has 36 climate controlled gondolas that can accommodate eight people each. A VIP gondola features a glass floor. It weighs 440 tonnes.
References.
9. Ubisoft, Operation Amber Sky Retrieved 2021-01-25.


Bridge passage


Barker lever

The Barker lever is a pneumatic system which multiplies the force of a finger on the key of a tracker pipe organ. It employs the wind pressure of the organ to inflate small bellows called "pneumatics" to overcome the resistance of the pallets (valves) in the organ's wind-chest . This lever allowed for the development of larger, more powerful organs still responsive to the human hand. These larger organs first flourished in France, e.g., the organ produced by Cavaillé-Coll at St. Sulpice. The first Barker lever was built in the Cavaillé-Coll organ of the Basilica of Saint-Denis.
This "contrivance" was named after Charles Spackman Barker (1804-79), engineer and organ-builder. A similar lever was developed by David Hamilton in 1835, and there has been debate whether Barker stole the design.


Goddard problem

In rocketry, the Goddard problem is to optimize the peak altitude of a rocket, ascending vertically, and taking into account atmospheric drag and the gravitational field. This was first posed by Robert H. Goddard in his 1919 publication, "A Method of Reaching Extreme Altitudes".


Leon P. Alford

Leon Pratt Alford (Jan. 3, 1877 – Feb. 2, 1942) was an American mechanical engineer, organizational theorist, and administrator for the American Society of Mechanical Engineers. known for his seminal work in the field of industrial management.
Biography.
Born in Simsbury, Connecticut, Alford graduated from the High School of Plainville, Connecticut, and in 1896 from the Worcester Polytechnic Institute. After ten years in the industry in various functions, he received his ME from Worcester Polytechnic Institute in 1905.
In 1896 Alford started as shop foreman at the McKay Metallic Fastening Assn. in Boston, which merged to McKay-Bigelow Heeling Assn. in 1897. After another two years as shop foreman, he found employ as production superintendent at the United Shoe Machinery Company in 1899 in Boston. The United Shoe Machinery Company, formed in 1899 out of the merger of three shoe machinery companies, developed revolutionary new shoemaking equipment, which revolutionized the shoe industry. The company employed 9,000 workers and in its best days supplied 85% of all shoemaking machines in the United States. In 1902 Alford got promoted to mechanical engineer, and invented and patented some new constructions for the United Shoe Machinery Company.
In 1907 Alford started working in engineering journalism for the Engineering Magazine company. From 1907 to 1911 he was engineering editor at the "American Machinist", and from 1911 to 1917 editor-in-chief. Sequentially he was editor for the "Industrial Management" from 1917 to 1920, from 1921 to 1923 editor for "Manufacturing Industrial Management," and from 1923 to 1928 consulting editor for the "Factory and Industrial Management" and vice-president of the Ronald Press Company in New York. Alford co-developed the theory called systematic management, and was an advocate of this management style within the American Society of Mechanical Engineers (ASME).
In 1929, Herbert Hoover appointed a president's commission to investigate the current state of the economy. Alford served on this panel and was the principal co-author of the committee's report, "Recent Economic Changes" (1929). From 1935 to 1937 he joined the Federal Communications Commission, where he was assistant engineer-in-charge of the manufacturing costs unit. In 1937 Alford jointed the faculty of New York University, where he became chairman of the department of administrative engineering.
Alford was elected fellow of the American Society of Mechanical Engineers and was its former vice-president, and fellow of the Institute of Management and its former president. He was awarded the first Melville Medal in 1927 and in 1929 the Henry Laurence Gantt Medal from the American Society of Mechanical Engineers.
Work.
Systematic management and scientific management.
Alford was a practitioner of systematic management and an advocate of this management style within the American Society of Mechanical Engineers. This systems of management principles, partly based on the ideas of Charles Babbage, was developed together with Alexander Hamilton Church, would paved the way to modern industrial management. Their views clashed with the scientific management approach advocated by Frederick Winslow Taylor. In 1912, Alford published a critique of scientific management that undermined Taylor's claims of success.
Alford argued that labor efficiency improvements at the Philadelphia plant of the Link-Belt Company were due to the personality of company's president, James Mapes Dodge. Dodge had won much respect and trust from the workers because of arrangements and incentives he offered so that they would accept Taylor's changes.
Later in 1912, Alford sat on the ASME committee that considered whether or not to publish Taylor's book, "The Principles of Scientific Management". Alford's criticisms of Taylor and his management techniques moderated the committee's position on the text. Because the committee's report was ambivalent about the merits of Scientific Management, the ASME declined to publish Taylor's book.
Industrial management.
Alford published his own management text, "Industrial Management". He advocated a reformist approach to labor and to unionism. In 1920, he co-founded the Management Division within the ASME. Alford advocated flexibility in "industrial relations" and "human engineering" and rejected fixed and rigid approaches to labor management such as scientific management. His approach to labor soon became the dominant accepted practice of corporate liberal management. Because of this approach, the Management Division soon became the largest division within the ASME.
Selected publications.
Books, a selection:
Articles, a selection:


Coffin ray

Hypnos monopterygius, also known as the coffin ray or Australian numbfish, is a species of electric ray endemic to Australia, where it is common in inshore waters shallower than . It is the sole member of its family Hypnidae. This small species typically reaches in length. Greatly enlarged pectoral fins and an extremely short tail, coupled with diminutive dorsal and caudal fins all concentrated towards the rear, give the coffin ray a distinctive pear-like shape. It is a varying shade of brown in color above, and has tiny eyes and a large, highly distensible mouth.
The sluggish and nocturnal coffin ray frequents sandy or muddy habitats, where it can bury itself during daytime. It can produce a powerful electric shock reaching 200 volts for attack and defense. This species is a voracious predator that feeds mainly on benthic bony fishes, often tackling fish approaching or exceeding itself in size. On occasion, it may also consume invertebrates and even small penguins and rats. Reproduction is aplacental viviparous, in which the developing embryos are nourished by yolk and maternally produced histotroph ("uterine milk"). The female gives birth to 4–8 pups during summer. The coffin ray can deliver a severe, albeit non-fatal, shock to a human. Not valued commercially, it is very hardy and can usually survive being captured and discarded. The International Union for Conservation of Nature (IUCN) has listed this species under Least Concern, as its population does not seem threatened by human activity.
Taxonomy and phylogeny.
The first scientific reference to the coffin ray was written by English zoologist and botanist George Shaw to accompany Frederick Polydore Nodder's illustrations of a beached fish, published in their 1795 work "The Naturalist's Miscellany". Shaw interpreted the specimen as a goosefish, calling it the "single-finned Lophius" or "Lophius monopterygius" in Latin. Independently, French zoologist Auguste Duméril described a new electric ray in an 1852 volume of the journal "Revue et Magasin de Zoologie", based on two specimens collected off New South Wales. He named it "Hypnos subnigrum"; the genus name is derived from the Greek word for "sleep", referring to the ray's ability to induce numbness. Eventually, Gilbert Percy Whitley recognized that Nodder had illustrated the same species that Duméril had described, and thus the proper binomial name became "Hypnos monopterygius". In 1902, Edgar Ravenswood Waite proposed "Hypnarce" as a replacement name for "Hypnos", which he believed was preoccupied by the butterfly genus "Hypna". However, the International Code of Zoological Nomenclature (ICZN) does not seem to require the change, and thus "Hypnarce" is regarded as a junior synonym.
The common name "coffin ray" comes from the coffin-like shape of beached specimens, which become bloated after death. This species may also be referred to as crampfish, electric ray, numbfish, numbie, short-tail electric ray, or torpedo. Phylogenetic studies, based on morphology, have found that "Hypnos" is most closely related to the genus "Torpedo". Hence, some taxonomists classify it with "Torpedo" in the family Torpedinidae (in its own subfamily, Hypninae). On the other hand, there are also taxonomists who believe "Hypnos" to be distinctive enough to merit its own separate family, Hypnidae.
Distribution and habitat.
The coffin ray has a wide but disjunct distribution in tropical and warm-temperate Australian waters. The western part of its range extends from Gulf St Vincent in South Australia to Broome in Western Australia, and the eastern part from Eden in New South Wales to Heron Island in Queensland. It does not occur off Victoria or Tasmania. This common, bottom-dwelling species is typically found close to shore, no deeper than , though it has been recorded from as deep as . It favors habitats with sandy or muddy bottoms, including beaches, estuaries, and bays, and can also be found over seagrass as well as on and around rocky and coral reefs.
Description.
The unusual pear-like shape of the coffin ray distinguishes it from all other rays. Its body is flabby, with two large, kidney-shaped electric organs visible on both sides of the head. The pectoral fins form a greatly enlarged disc about as wide as long, that is thick at the center and thin at the margins. The leading margin of the disc is straight to gently concave. The eyes are minute and can be elevated on short stalks. Close behind the eyes and slightly larger are the spiracles, which are rimmed by small papillae in some individuals. The nostrils are located just ahead of the mouth, and are connected to it by a pair of broad grooves. Between the nostrils is a short curtain of skin that overlaps the mouth. The capacious mouth forms a very long, wide arch; the slender jaws can be distended dramatically, though are not particularly protrusible. Adults have over 60 rows of small teeth in either jaw; each tooth has three long cusps. The five pairs of gill slits are small and placed beneath the disc.
The pelvic fins are relatively large and merged with the pectoral fin disc at the front to form a roughly circular secondary disc. The two dorsal fins are shaped like rounded lobes and are located very close to the caudal fin, which is of similar size with a nearly symmetrical, rounded margin. The tail is extremely short, such as that the caudal fin barely extends past the pelvic fin disc. The skin is entirely devoid of dermal denticles, and may be creased in areas. The dorsal coloration ranges from dark to reddish brown, to grayish, pinkish, or yellowish, and may be plain or sparsely patterned with irregular darker and lighter markings. The underside is pale, as are the spiracle papillae. This species grows to a length of , or possibly even , though most are only around long.
Biology and ecology.
The coffin ray is a slow and weak swimmer that moves forward with a jerky, fluttery motion. It is nocturnal and spends most of the day buried in sediment with only its spiracles showing. When disturbed, it has been observed performing a possible defense behavior, wherein it erupts from the bottom and swims in a loop with its mouth agape. This species is sometimes stranded on land by the ebbing tide, but can survive out of water for hours. Like in other electric rays, the coffin ray's electric organs are derived from muscle tissue and consist of numerous vertical columns, each formed from a stack of jelly-filled "electric plates" that essentially acts as a battery. It is capable of generating up to 200 volts of electricity and delivering 50 shocks over span of ten minutes, with each successive shock weakening. The coffin ray employs electricity both to subdue prey and deter predators.
The diet of the coffin ray consists mostly of benthic bony fishes, but also includes cephalopods and on occasion crustaceans and polychaete worms. Penguins and rats have also been recorded from the stomachs of this species. The coffin ray ambushes prey from the substrate, and swallows them whole head-first before re-burying. It often takes extremely large prey relative to its size; one observed individual long had swallowed a flathead ("Platycephalus" sp.) long, and the tail of the prey fish was still protruding from its mouth. Dead specimens have been recovered that had apparently choked trying to swallow too-large prey. The coffin ray is aplacental viviparous, in which the developing embryos are nourished by yolk, later supplemented by histotroph ("uterine milk") secreted by the mother. Females give birth to litters of 4–8 pups in summer; the newborns measure approximately long. Males and females both attain sexual maturity around long. This species is known to be parasitized by the tapeworms "Acanthobothrium angelae" and "Lacistorhynchus dollfusi", and the nematode "Echinocephalus overstreeti".
Human interactions.
When approached, the coffin ray tends to keep still in its place of concealment on the sea floor. As a result, many divers, swimmers, and bathers have been shocked after accidentally contacting it. While not life-threatening, the shock can be quite severe. The shock can still be perceived by a person pouring a stream of seawater on the ray. The coffin ray has no economic value. In 1883, Edward Pierson Ramsay noted that it was the only ray native to Port Jackson that was inedible. It is caught incidentally by commercial trawlers, but is hardy enough to usually be returned to the water alive. It is also caught in lobster traps and infrequently taken by spear fishers. As it remains common and widespread, the International Union for Conservation of Nature (IUCN) has assessed this species as Least Concern. It has been kept in public aquariums, but requires moving food.


Barrett REC7

The Barrett REC7 (designation stands for "reliability-enhanced carbine") is an American firearm manufactured as a selective-fire fully-automatic and semi-automatic rifle by Barrett Firearms. It is an M4 carbine utilizing a short-stroke gas piston system. REC7 is available in either 5.56×45mm NATO or 6.8mm Remington SPC. The REC7 is Barrett’s second AR-pattern rifle chambered for the 6.8mm Remington SPC cartridge, the first being the Barrett M468 rifle. The 6.8 SPC-chambered M468 rifle employed the same direct gas-impingement system as the M4.
Design and features.
Unlike possible replacements for the M16/M4 such as the now canceled XM8, the REC7 is not an entirely new rifle, instead it is made up of an upper receiver that is attached to a M16/M4 lower receiver and is compatible with many accessories intended for the M16/M4 family. It can also be mated to M16/M4 lower receivers currently in the possession of the US military. The rifle uses a short-stroke gas piston mechanism, unlike the M16 or M4 which use direct impingement.
In addition, the REC7 uses the new 6.8mm Remington SPC (6.8×43mm) cartridge, a round that is of roughly equivalent length to 5.56×45mm NATO ammunition, so it is compatible with a standard-size lower receiver currently in use by the United States military.
The REC7 uses a short-stroke gas piston designed by Barrett. It rides above the barrel and is housed inside the fore-end. The spring-loaded piston is a one-piece 17-4 stainless steel rod. The forward and rearward movement of the piston is approximately one inch.
Like many AR-15 type rifles, such as the M16/M4, the barrel is threaded to allow muzzle attachments such as a suppressor. The REC7 employs a free-floating Daniel Defense rail system, which allows many military accessories such as a bipod, night vision devices, and combat optics to be placed on the rifle. The REC7 features forged 7075 aluminum upper and lower receivers that are hard-coat anodized a deep black. The lower receiver has a single-stage trigger, a Magpul enhanced trigger guard for firing with gloves, and a beveled magazine well for rapid magazine changes. The upper receiver is flat-top with a Picatinny rail. The barrel is chrome-lined and is fitted with a M16A2 flash suppressor, a six-position Magpul MOE butt stock and pistol grip.
The REC7 outfitted in a shortened barrel PDW configuration was one of the weapons displayed to U.S. Army officials during an invitation-only Industry Day on November 13, 2008. The goal of the Industry Day was to review current carbine technology prior to writing formal requirements for a future replacement for the M4 carbine.
The Barrett Enhanced Bolt is made from high-strength 9310 steel. The bolt is designed specifically for use in the piston operated REC7, not just adapted from a direct gas bolt. The bolt’s gas-ring-free design is easy to clean. Reinforced at critical areas, every bolt is proofed and magnetic-particle inspected to guarantee reliable performance.
At the heart of the operating system is a nitrided, two-position, forward-venting gas plug that retains the piston. The piston can be accessed through the front of the gas block without removing the handguard so optical sights or laser devices do not need to be zeroed after routine maintenance.
The REC7 rifle’s forged 7075 aluminum upper and lower receivers are Type 3 hardcoat anodized. The lower houses an ultra-dependable single-stage trigger. The upper supports a free-floated, hammer-forged, chrome-lined barrel with M4 feed ramps machined into the receiver and the barrel extension. A mil-spec A2 flash hider protects the muzzle.


SS Narragansett

The SS "Narragansett" was a passenger paddle steamer of the Stonington Line that burned and sank on June 11, 1880, after a collision with her sister ship the SS "Stonington" in Long Island Sound.
The "Narragansett" had taken on approximately 300 passengers at the North River Pier at Jay St. in New York City at 5:00 pm. Later that evening, at around 11:30 pm, in heavy fog, she collided with the "Stonington" near the mouth of the Connecticut River. The "Stonington" was damaged, but was able to return to a port and took no casualties. The "Narragansett" had a huge gash in the side of her hull, caught fire and burned rapidly. Many of the passengers asleep in their staterooms were unable to escape.
Significant controversy followed the collision, as the captains of the two ships gave different accounts of the accident and the events leading up to it, and the crew of the "Narragansett" faced accusations of neglecting its duty. Approximately 50 passengers and at least five crewman, lost their lives on the "Narragansett".
Historical note.
One of the passengers on the "Stonington" was Charles J. Guiteau who, just over a year later, assassinated President James A. Garfield. Guiteau was on deck at the time of the collision, and afterwards believed that he had been miraculously spared to punish Garfield.
One of the passengers on the "Narragansett" was John Reilly of the Cincinnati Stars, who was en-route to Providence to meet up with his team. After the collision, Reilly put a life preserver on and jumped overboard. He was in the water for over an hour.


Phil Muntz

Eric Phillip Muntz (May 18, 1934 – August 1, 2017) was a prominent American scientist and a former Canadian football player who played for the Calgary Stampeders in 1956 and Toronto Argonauts from 1957 to 1960. He previously played at the University of Toronto
where he received a B.S. degree in Aeronautical Engineering in 1956 and a PhD in 1961 specializing in Aerophysics.
Since 1969, Muntz was a professor at University of Southern California Phil Muntz made important contributions to the development of electron beam fluorescence technique as well as its applications for high-speed flow measurements. He was an inventor on over 25 patents.
In 1993, Muntz was elected a member of US National Academy of Engineering with the citation "For technical and academic leadership in rarified-gas dynamics and non-equilibrium flow phenomena".
In late 1990s and early 2000s, Muntz introduced and developed the concept of Knudsen compressor, a multi-stage vacuum pump with no moving parts or fluids. He died on August 1, 2017.


Panel dividing equipment

Panel dividing equipment is a type of woodworking machine (panel line) that is intended to divide master panel into sized parts.
A panel saw is one such device.