Cam

A cam is a rotating or sliding piece in a mechanical linkage used especially in transforming rotary motion into linear motion.[1][2] It is often a part of a rotating wheel (e.g. an eccentric wheel) or shaft (e.g. a cylinder with an irregular shape) that strikes a lever at one or more points on its circular path. The cam can be a simple tooth, as is used to deliver pulses of power to a steam hammer, for example, or an eccentric disc or other shape that produces a smooth reciprocating (back and forth) motion in the follower, which is a lever making contact with the cam.

Nockenwelle ani
Fig. 1 Animation showing rotating cams and cam followers producing reciprocating motion.
Elliptical cam mechanism
Elliptical disk cam with oscillating follower.

Overview

The cam can be seen as a device that rotates from spherical to reciprocating (or sometimes oscillating) motion.[3] A common example is the camshaft of an automobile, which takes the rotary motion of the engine and translates it into the reciprocating motion necessary to operate the intake and exhaust valves of the cylinders.

Displacement diagram

Basic Displacement Diagram
Fig. 2 Basic displacement diagram

Certain cams can be characterized by their displacement diagrams, which reflect the changing position a roller follower (a shaft with a rotating wheel at the end) would make as the cam rotates about an axis. These diagrams relate angular position, usually in degrees, to the radial displacement experienced at that position. Displacement diagrams are traditionally presented as graphs with non-negative values. A simple displacement diagram illustrates the follower motion at a constant velocity rise followed by a similar return with a dwell in between as depicted in figure 2.[4] The rise is the motion of the follower away from the cam center, dwell is the motion where the follower is at rest, and return is the motion of the follower toward the cam center.[5]

However, the most common type is in the valve actuators in internal combustion engines. Here, the cam profile is commonly symmetric and at rotational speeds generally met with, very high acceleration forces develop. Ideally, a convex curve between the onset and maximum position of lift reduces acceleration, but this requires impractically large shaft diameters relative to lift. Thus, in practice, the points at which lift begins and ends mean that a tangent to the base circle appears on the profile. This is continuous with a tangent to the tip circle. In designing the cam, the lift and the dwell angle are given. If the profile is treated as a large base circle and a small tip circle, joined by a common tangent, giving lift , the relationship can be calculated, given the angle between one tangent and the axis of symmetry ( being ), while is the distance between the centres of the circles (required), and is the radius of the base (given) and that of the tip circle (required)

and

Disc or Plate cam

Cam Profile
Fig. 3 Cam profile

The most commonly used cam is the cam plate (also known as disc cam or radial cam[6]) which is cut out of a piece of flat metal or plate.[7] Here, the follower moves in a plane perpendicular to the axis of rotation of the camshaft.[8] Several key terms are relevant in such a construction of plate cams: base circle, prime circle (with radius equal to the sum of the follower radius and the base circle radius), pitch curve which is the radial curve traced out by applying the radial displacements away from the prime circle across all angles, and the lobe separation angle (LSA - the angle between two adjacent intake and exhaust cam lobes).

The base circle is the smallest circle that can be drawn to the cam profile.

A once common, but now outdated, application of this type of cam was automatic machine tool programming cams. Each tool movement or operation was controlled directly by one or more cams. Instructions for producing programming cams and cam generation data for the most common makes of machine were included in engineering references well into the modern CNC era.[9]

This type of cam is used in many simple electromechanical appliance controllers, such as dishwashers and clothes washing machines, to actuate mechanical switches that control the various parts.

Cylindrical cam

Gearbox
Motorcycle transmission showing cylindrical cam with three followers. Each follower controls the position of a shift fork.
Threading setup helix and bushing American pacemaker lathe
Constant lead barrel cam in an American Pacemaker lathe. This cam is used to provide a repeatable cross slide setting when threading with a single-point tool.

A cylindrical cam or barrel cam is a cam in which the follower rides on the surface of a cylinder. In the most common type, the follower rides in a groove cut into the surface of a cylinder. These cams are principally used to convert rotational motion to linear motion parallel to the rotational axis of the cylinder. A cylinder may have several grooves cut into the surface and drive several followers. Cylindrical cams can provide motions that involve more than a single rotation of the cylinder and generally provide positive positioning, removing the need for a spring or other provision to keep the follower in contact with the control surface.

Applications include machine tool drives, such as reciprocating saws, and shift control barrels in sequential transmissions, such as on most modern motorcycles.

A special case of this cam is constant lead, where the position of the follower is linear with rotation, as in a lead screw. The purpose and detail of implementation influence whether this application is called a cam or a screw thread, but in some cases, the nomenclature may be ambiguous.

Cylindrical cams may also be used to reference an output to two inputs, where one input is rotation of the cylinder, and the second is position of the follower axially along the cam. The output is radial to the cylinder. These were once common for special functions in control systems, such as fire control mechanisms for guns on naval vessels[10] and mechanical analog computers.[11]

An example of a cylindrical cam with two inputs is provided by a duplicating lathe, an example of which is the Klotz axe handle lathe,[12] which cuts an axe handle to a form controlled by a pattern acting as a cam for the lathe mechanism.

Face cam

A face cam produces motion by using a follower riding on the face of a disk. The most common type has the follower ride in a slot so that the captive follower produces radial motion with positive positioning without the need for a spring or other mechanism to keep the follower in contact with the control surface. A face cam of this type generally has only one slot for a follower on each face. In some applications, a single element, such as a gear, a barrel cam, or other rotating element with a flat face, may do duty as a face cam in addition to other purposes.

Face cams may provide repetitive motion with a groove that forms a closed curve, or may provide function generation with a stopped groove. Cams used for function generation may have grooves that require several revolutions to cover the complete function, and in this case, the function generally needs to be invertible so that the groove does not self intersect, and the function output value must differ enough at corresponding rotations that there is sufficient material separating the adjacent groove segments. A common form is the constant lead cam, where displacement of the follower is linear with rotation, such as the scroll plate in a scroll chuck. Non-invertible functions, which require the groove to self-intersect, can be implemented using special follower designs.

Sash lock
Sash window lock, traditional cam style, for double-hung sash window

A variant of the face cam provides motion parallel to the axis of cam rotation. A common example is the traditional sash window lock, where the cam is mounted to the top of the lower sash, and the follower is the hook on the upper sash. In this application, the cam is used to provide mechanical advantage in forcing the window shut, and also provides a self-locking action, like some worm gears, due to friction.

Face cams may also be used to reference a single output to two inputs, typically where one input is rotation of the cam and the other is radial position of the follower. The output is parallel to the axis of the cam. These were once common is mechanical analog computation and special functions in control systems.[13]

A face cam that implements three outputs for a single rotational input is the stereo phonograph, where a relatively constant lead groove guides the stylus and tone arm unit, acting as either a rocker-type (tone arm) or linear (linear tracking turntable) follower, and the stylus alone acting as the follower for two orthogonal outputs to representing the audio signals. These motions are in a plane radial to the rotation of the record and at angles of 45 degrees to the plane of the disk (normal to the groove faces). The position of the tone arm was used by some turntables as a control input, such as to turn the unit off or to load the next disk in a stack, but was ignored in simple units.

Heart shaped cam

This type of cam, in the form of a symmetric heart symbol, is used to return a shaft holding the cam to a set position by pressure from a roller. They were used for example on early models of Post Office Master clocks to synchronise the clock time with Greenwich Mean Time when the activating follower was pressed onto the cam automatically via a signal from an accurate time source.[14]

Snail drop cam

This type of cam was used for example in mechanical time keeping clocking-in clocks to drive the day advance mechanism at precisely midnight and consisted of a follower being raised over 24 hours by the cam in a spiral path which terminated at a sharp cut off at which the follower would drop down and activate the day advance. Where timing accuracy is required as in clocking-in clocks these were typically ingeniously arranged to have a roller cam follower to raise the drop weight for most of its journey to near its full height, and only for the last portion of its travel for the weight to be taken over and supported by a solid follower with a sharp edge. This ensured that the weight dropped at a precise moment, enabling accurate timing.[15] This was achieved by the use of two snail cams mounted coaxially with the roller initially resting on one cam and the final solid follower on the other but not in contact with its cam profile. Thus the roller cam was initially carried the weight, until at the final portion of the run the profile of the non-roller cam rose more than the other causing the solid follower to take the weight.

Linear cam

A linear cam is one in which the cam element moves in a straight line rather than rotates. The cam element is often a plate or block, but may be any cross section.[16] The key feature is that the input is a linear motion rather than rotational. The cam profile may be cut into one or more edges of a plate or block, may be one or more slots or grooves in the face of an element, or may even be a surface profile for a cam with more than one input. The development of a linear cam is similar to, but not identical to, that of a rotating cam.[17]

Copiadora llaves
Key duplicating machine. The original key (mounted in the left hand holder) acts as a linear cam to control the cut depth for the duplicate.

A common example of a linear cam is a key for a pin tumbler lock. The pins act as the followers. This behavior is exemplified when the key is duplicated in a key duplication machine, where the original key acts as a control cam for cutting the new key.

History

An early cam was built into Hellenistic water-driven automata from the 3rd century BC.[18] The cam and camshaft later appeared in mechanisms by Al-Jazari, who used them in his automata, described in 1206.[19] The cam and camshaft appeared in European mechanisms from the 14th century.[20]

See also

References

  1. ^ "cam definition". Merriam Webster. Retrieved 2010-04-05. a rotating or sliding piece (as an eccentric wheel or a cylinder with an irregular shape) in a mechanical linkage used especially in transforming rotary motion into linear motion or vice versa
  2. ^ G., Shigley, J., & Uicker, J. (2010). Cam Design. Theory of machines and Mechanisms (4 ed.). Oxford University Press, USA. p. 200.CS1 maint: Multiple names: authors list (link)
  3. ^ Jensen, Preddben w. (1965). Cam Design and Manufacture. The Industrial Press, New York. p. 1.
  4. ^ Cam Design and Manufacture. The Industrial Press, New York. p. 8.
  5. ^ Introduction to Mechanisms - Cams"rise is the motion of the follower away from the cam center, dwell is the motion where the follower is at rest, and return is the motion of the follower toward the cam center"
  6. ^ "Cams; their profiles and the velocity and acceleration of their associated followers". Retrieved 29 August 2013.
  7. ^ Jensen, Preben w. (1965). Cam Design and Manufacture. The Industrial Press, New York. p. 1.
  8. ^ Introduction to Mechanisms - Cams "The follower moves in a plane perpendicular to the axis of rotation of the camshaft."
  9. ^ Oberg, Erik (1996). Machinery's Handbook, 25th Ed. Industrial Press. pp. 1050–1055.
  10. ^ Bomar, Null, and Wallace (1996). Gunners Mate 1 & C NAVEDTRA 14110. Naval Education and Training Professional Development and Technology Center. p. 4-2.CS1 maint: Multiple names: authors list (link)
  11. ^ Clymer, A. Ben. "The Mechanical Analog Computers of Hannibal Ford and William Newell". IEEE Annals of the History of Computing. 15 (2): 19–34. doi:10.1109/85.207741.
  12. ^ House handles Klotz lathe.
  13. ^ Bomar, Null, and Wallace (1996). Gunners Mate 1 & C NAVEDTRA 14110. Naval Education and Training Professional Development and Technology Center. p. 4-1.CS1 maint: Multiple names: authors list (link)
  14. ^ https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSnQxblcFmDowNoS4C-voIymQHG6o8sEAlxC9zAqhVivxtq6nsYwA
  15. ^ https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcQ5FMCIxzU8XAbFpEiXgZGi-GgRHVeci71oxiGHc9HTn8mUGEhG
  16. ^ "Linear cam mechanical interlock".
  17. ^ "Calculation equations:cams". Retrieved 29 August 2013.
  18. ^ Wilson, Andrew (2002): "Machines, Power and the Ancient Economy", The Journal of Roman Studies, Vol. 92, pp. 1–32 (16) https://www.jstor.org/stable/3184857
  19. ^ Georges Ifrah (2001). The Universal History of Computing: From the Abacus to the Quantum Computer, p. 171, Trans. E.F. Harding, John Wiley & Sons, Inc. (See [1])
  20. ^ A. Lehr (1981), De Geschiedenis van het Astronomisch Kunstuurwerk, p. 227, Den Haag. (See [2])

External links

Alternative medicine

Alternative medicine, fringe medicine, pseudomedicine or simply questionable medicine is promotion or use of practices which are unproven, disproven, impossible to prove, or excessively harmful in relation to their effect — in the attempt to achieve the healing effects of medicine. It differs from experimental medicine in that the latter employs responsible investigation, and is discarded when shown ineffective. The scientific consensus is that alternative therapies either do not, or cannot, work. In some cases laws of nature are violated by their basic claims; in others the treatment is so much worse that its use is unethical. Alternative practices, products, and therapies range from those which are simply ineffective to those having known harmful and toxic effects.

Alternative therapies may be credited for perceived improvement through placebo effects, decreased use or effect of medical treatment (and therefore either decreased side effects; or nocebo effects towards standard treatment), or the natural course of the condition or disease. Alternative treatment is not the same as experimental treatment or traditional medicine, although both can be misused in ways that are alternative. Alternative or complementary medicine is dangerous because it may discourage people from getting the best possible treatment, and may lead to a false understanding of the body and of science.

Alternative medicine is used by a significant number of people, though its popularity is often overstated. Large amounts of funding go to testing alternative medicine, with more than US$2.5 billion spent by the United States government alone. None have shown any effect beyond that of false treatment, and most studies showing any effect have been statistical flukes. Alternative medicine is a highly profitable industry, with a strong lobby. This fact is often overlooked by media or intentionally kept hidden, with alternative practice being portrayed positively when compared to "big pharma". The lobby has successfully pushed for alternative therapies to be subject to far less regulation than conventional medicine. Alternative therapies may even be allowed to promote use when there is demonstrably no effect, only a tradition of use. Regulation and licensing of alternative medicine and health care providers varies between and within countries. Despite laws making it illegal to market or promote alternative therapies for use in cancer treatment, many practitioners promote them. Alternative medicine is criticized for taking advantage of the weakest members of society.

Terminology has shifted over time, reflecting the preferred branding of practitioners. For example, the United States National Institutes of Health department studying alternative medicine, currently named National Center for Complementary and Integrative Health, was established as the Office of Alternative Medicine and was renamed the National Center for Complementary and Alternative Medicine before obtaining its current name. Therapies are often framed as "natural" or "holistic", in apparent opposition to conventional medicine which is "artificial" and "narrow in scope", statements which are intentionally misleading. When used together with functional medical treatment, alternative therapies do not "complement" (improve the effect of, or mitigate the side effects of) treatment. Significant drug interactions caused by alternative therapies may instead negatively impact functional treatment by making prescription drugs less effective, such as interference by herbal preparations with warfarin.

Alternative diagnoses and treatments are not part of medicine, or of science-based curricula in medical schools, nor are they used in any practice based on scientific knowledge or experience. Alternative therapies are often based on religious belief, tradition, superstition, belief in supernatural energies, pseudoscience, errors in reasoning, propaganda, fraud, or lies. Alternative medicine is based on misleading statements, quackery, pseudoscience, antiscience, fraud, and poor scientific methodology. Promoting alternative medicine has been called dangerous and unethical. Testing alternative medicine that has no scientific basis has been called a waste of scarce research resources. Critics state that "there is really no such thing as alternative medicine, just medicine that works and medicine that doesn't". that the very idea of "alternative" treatments is paradoxical, as any treatment proven to work is by definition "medicine",

The US NCCIH alone has spent around $2.5bn in grants without validating a single alternative therapy.

CAMK

CAMK, also written as CaMK, is an abbreviation for the Ca2+/calmodulin-dependent protein kinase class of enzymes. CAMKs are activated by increases in the concentration of intracellular calcium ions (Ca2+) and transfers phosphates from ATP to defined serine or threonine residues in other proteins. Activated CAMK is involved in the phosphorylation of transcription factors and therefore, in the regulation of expression of responding genes. Members of this enzyme class include:

CAMKICAMKIα

CAMKIβ

CAMKIδ

CAMKIγ

CAMKIICAMKIIα

CAMKIIβ

CAMKIIδ

CAMKIIγ

CAMKIII

CAMKIV

SCAMK

CAM ship

CAM ships were World War II-era British merchant ships used in convoys as an emergency stop-gap until sufficient escort carriers became available. CAM ship is an acronym for catapult aircraft merchant ship.They were equipped with a rocket-propelled catapult launching a single Hawker Hurricane, dubbed a "Hurricat" or "Catafighter" to destroy or drive away an attacking bomber. Normally the Hurricane fighter would be lost when the pilot then bailed out or ditched in the ocean near the convoy. CAM ships continued to carry their normal cargoes after conversion.

The concept was developed and tested by the five fighter catapult ships, commissioned as warships and commanded and crewed by the Royal Navy - but the CAM ships were merchant vessels, commanded and crewed by the Merchant Navy.

Cam'ron

Cameron Ezike Giles (born February 4, 1976), known professionally as Cam'ron (formerly Killa Cam), is an American rapper, actor and entrepreneur from Harlem, New York. He is the de facto leader of East Coast hip hop group The Diplomats (also known as Dipset), and is a member of the duo U.N. (Us Now). Cam'ron was also a part of the group Children of the Corn before they disbanded in 1997.

In 1998, Cam'ron released his debut album Confessions of Fire on Epic, the album would achieve Gold status by the RIAA. In 2000 Cam'ron released his second album S.D.E. (Sports Drugs & Entertainment). In 2001 Cam'ron signed a new label deal with Roc-A-Fella Records and released his critically acclaimed, third studio album Come Home with Me. it achieved Platinum status by the RIAA, and also contained Cam'ron's highest charting Billboard single to date, "Oh Boy," featuring his artist at the time Juelz Santana. In 2002 Cam'ron starred in the Roc-A-Fella films Paper Soldiers and Paid in Full. In 2004 Cam'ron released his fourth studio album Purple Haze to critical acclaim reaching Gold status by the RIAA.

In 2005 after disbanding his record label, Diplomat Records, from Roc-A-Fella Records due to business disagreements, Cam'ron signed the label to a distribution deal with Asylum Records. In 2006 Cam'ron released his fifth studio album, Killa Season. The album also contained a film of the same name, in which Cam'ron made his director/screenwriter debut and starred as the main character. In 2009, after taking a hiatus due to his mother's health, Cam'ron returned to music and released his sixth studio album Crime Pays. It reached number 3 on the Billboard 200.

Cam'ron is currently working on his seventh studio album titled Purple Haze 2, which he has stated will be his final album, however in June 2016 in an interview with DJ Whoo Kid he stated that his album had been renamed to Killa Season 2: The Pink Edition with an approximate release date of November 2016 with no mention of the project being his final album. The first single from the album "Oh Yeah" was released on May 19, 2016 and featured Juelz Santana.

Cam Gigandet

Cameron Joslin "Cam" Gigandet (; born August 16, 1982) is an American actor whose credits include a recurring role on The O.C. and appearances in feature films Twilight, Pandorum, Never Back Down, Burlesque, Easy A, The Roommate and Priest. He also starred in the short-lived CBS legal drama series Reckless. From 2016 to 2018, Gigandet starred in the Audience Network drama series Ice.

Cam Newton

Cameron Jerrell Newton (born May 11, 1989) is an American football quarterback for the Carolina Panthers of the National Football League (NFL). He played college football at Auburn and was drafted as the first overall pick by the Panthers in the 2011 NFL Draft. Newton is the only player in the modern era to be awarded the Heisman Trophy, win a national championship, and become the first overall pick in an NFL draft within a one-year span. He was the 2011 NFL Rookie of the Year, is a three-time Pro Bowler, and was named the NFL MVP in 2015.

In his rookie year, Newton broke all-time NFL rookie records for passing and rushing yards. He became the first NFL quarterback to throw for 400 yards in his first game, shattering Peyton Manning's first-game record by 120 yards. He also broke Otto Graham's 61-year-old record for passing yards by any quarterback in an NFL debut. Newton went on to become the first rookie quarterback to throw for 4,000 yards in a season. He also ran for 14 touchdowns, more in a single season than any quarterback in NFL history, breaking Steve Grogan's 35-year-old record.In 2015, Newton became the first quarterback in NFL history to throw for at least 30 touchdowns and rush for 10 in the same season (35 passing, 10 rushing). He also became the only quarterback ever to have 300 yards passing, 5 touchdown passes, and over 100 yards rushing in the same game. Newton capped off the 2015 season by capturing MVP honors and leading the Panthers to a 15–1 record and a trip to Super Bowl 50.

Camshaft

A camshaft is a shaft to which a cam is fastened or of which a cam forms an integral part.

Computer-aided manufacturing

Computer-aided manufacturing (CAM) is the use of software to control machine tools and related ones in the manufacturing of workpieces. This is not the only definition for CAM, but it is the most common; CAM may also refer to the use of a computer to assist in all operations of a manufacturing plant, including planning, management, transportation and storage. Its primary purpose is to create a faster production process and components and tooling with more precise dimensions and material consistency, which in some cases, uses only the required amount of raw material (thus minimizing waste), while simultaneously reducing energy consumption.

CAM is now a system used in schools and lower educational purposes.

CAM is a subsequent computer-aided process after computer-aided design (CAD) and sometimes computer-aided engineering (CAE), as the model generated in CAD and verified in CAE can be input into CAM software, which then controls the machine tool. CAM is used in many schools alongside Computer-Aided Design (CAD) to create objects.

Go!Cam

The PSP Camera is a digital camera peripheral by Sony Computer Entertainment for the PlayStation Portable handheld video game system. In Japan, the PSP-300 was released as the Chotto Shot (ちょっとショット, "Quick Shot") on November 2, 2006, and was released in Singapore in the same year. For PAL regions, it is named the Go!Cam and was released May 25, 2007. A lower resolution version, the PSP-450x, was introduced in 2009. The PSP-450x camera was released in North America bundled with Invizimals on October 12, 2010, and was also bundled with EyePet on November 2, 2010.

The camera mounts on top of the PSP via the Mini USB connection slot and a screw. It can take still photographs and record video with audio. The microphone can also be used with the Talkman program and others.

Mount Wellington (New York)

Mount Wellington is a mountain located in the Central New York Region of New York near Springfield Center at the northern end of Otsego Lake. Mount Wellington rises 600 feet (180 m) above lake level. The extreme southern point of the mountain is called "Shad Cam". It is known as "The Sleeping Lion", as it looks similar to a lion laying down, viewed from Cooperstown, New York. It was originally named Mount Millington, but was renamed by George Hyde Clarke in honor of the Duke of Wellington, the victor of Waterloo, who had been Clarke's schoolmate at Eton College in England. Clarke Point is located on the lake, at the southern edge of the mountain.

Multiple-camera setup

The multiple-camera setup, multiple-camera mode of production, multi-camera or simply multicam is a method of filmmaking and video production. Several cameras—either film or professional video cameras—are employed on the set and simultaneously record or broadcast a scene. It is often contrasted with single-camera setup, which uses one camera.

Generally, the two outer cameras shoot close-up shots or "crosses" of the two most active characters on the set at any given time, while the central camera or cameras shoot a wider master shot to capture the overall action and establish the geography of the room. In this way, multiple shots are obtained in a single take without having to start and stop the action. This is more efficient for programs that are to be shown a short time after being shot as it reduces the time spent in film or video editing. It is also a virtual necessity for regular, high-output shows like daily soap operas. Apart from saving editing time, scenes may be shot far more quickly as there is no need for re-lighting and the set-up of alternative camera angles for the scene to be shot again from the different angle. It also reduces the complexity of tracking continuity issues that crop up when the scene is reshot from the different angles. It is an essential part of live television.

Drawbacks include a less optimized lighting which needs to provide a compromise for all camera angles and less flexibility in putting the necessary equipment on scene, such as microphone booms and lighting rigs. These can be efficiently hidden from just one camera but can be more complicated to set up and their placement may be inferior in a multiple-camera setup. Another drawback is in film usage—a four-camera setup may use (depending on the cameras involved) up to four times as much film (or storage space for digital) per take, compared with a single-camera setup.

While shooting, the director and assistant director create a line cut by instructing the technical director (or vision mixer in UK terminology) to switch between the feeds from the individual cameras. In the case of sitcoms with studio audiences, this line cut is typically displayed to them on studio monitors. The line cut might be refined later in editing, as often the output from all cameras is recorded, both separately and as a combined reference display called the q split. The camera currently being recorded to the line cut is indicated by a tally light controlled by a camera control unit (CCU) on the camera as a reference both for the actors and the camera operators.

Nest Labs

Nest Labs is an American manufacturer of smart home products including thermostats, smoke detectors, and security systems including smart doorbells and smart locks. Its flagship product, which was the company's first offering, is the Nest Learning Thermostat that was introduced in 2011. The product is programmable, self-learning, sensor-driven, and Wi-Fi-enabled – features that are often found in other Nest products. It was followed by the Nest Protect smoke and carbon monoxide detector in October 2013. After its acquisition of Dropcam in 2014, the company introduced its Nest Cam branding of security cameras beginning in June 2015.Co-founded by former Apple engineers Tony Fadell and Matt Rogers in 2010, the company quickly expanded to more than 130 employees by the end of 2012. Google acquired Nest Labs for US$3.2 billion in January 2014, when the company employed 280. As of late 2015, Nest employs more than 1,100 and has a primary engineering center in Seattle.

Nissan RB engine

The RB engine is a 2.0–3.0 L straight-6 four-stroke gasoline from Nissan, produced from 1985–2004.

Both SOHC and DOHC versions have an aluminium head. The SOHC versions have 2 valves per cylinder and the DOHC versions have 4 valves per cylinder; each cam lobe moves only one valve. All RB engines have belt-driven cams and a cast iron block. Most turbo models have an intercooled turbo (the exceptions being the single cam RB20ET & RB30ET engines), and most have a recirculating factory blow off valve (the exceptions being when fitted to Laurels and Cefiros) to reduce compressor surge when the throttle quickly closes. The Nissan RB Engine is derived from the six cylinder Nissan L20A engine which has the same bore and stroke as the RB20. All RB engines were made in Yokohama, Japan where the new VR38DETT is now made. Some RB engines were rebuilt by Nissan's NISMO division at the Omori Factory in Tokyo as well. All Z-Tune Skylines were rebuilt at the Omori Factory.

Overhead camshaft

Overhead camshaft, commonly abbreviated to OHC, is a valvetrain configuration which places the camshaft of an internal combustion engine of the reciprocating type within the cylinder heads ("above" the pistons and combustion chambers) and drives the valves or lifters in a more direct manner compared with overhead valves (OHV) and pushrods.

Overhead valve engine

An overhead valve engine (OHV engine), or "pushrod engine", is a reciprocating piston engine whose poppet valves are sited in the cylinder head. An OHV engine's valvetrain operates its valves via a camshaft within the cylinder block, cam followers (or "tappets"), pushrods, and rocker arms.

The OHV engine was an advance over the older flathead engine, whose valves were sited within the cylinder block. Some early "OHV" engines known as "F-heads" used both side-valves and overhead valves. A further advance over the OHV design is the overhead camshaft, or "OHC", engine, whose camshaft lies in the cylinder head itself, above the valves. To avoid confusion, OHC engines are not referred to as OHV despite also having their valves in the head.

River Cam

The River Cam is the main river flowing through Cambridge in eastern England. After leaving Cambridge, it flows north and east into the Great Ouse to the south of Ely at Pope's Corner. The Great Ouse connects the Cam to the North Sea at King's Lynn: The total distance from Cambridge to the sea is about 40 mi (64 km) and is navigable for punts, small boats, and rowing craft. The Great Ouse also connects to England's canal system via the Middle Level Navigations and the River Nene. In total, the Cam runs for around 69 kilometres (43 mi) from its furthest source (near Debden in Essex) to its confluence with the Great Ouse.

Variable valve timing

In internal combustion engines, variable valve timing (VVT) is the process of altering the timing of a valve lift event, and is often used to improve performance, fuel economy or emissions. It is increasingly being used in combination with variable valve lift systems. There are many ways in which this can be achieved, ranging from mechanical devices to electro-hydraulic and camless systems. Increasingly strict emissions regulations are causing many automotive manufacturers to use VVT systems.

Two-stroke engines use a power valve system to get similar results to VVT.

Webcam

A webcam is a video camera that feeds or streams its image in real time to or through a computer to a computer network. When "captured" by the computer, the video stream may be saved, viewed or sent on to other networks travelling through systems such as the internet, and e-mailed as an attachment. When sent to a remote location, the video stream may be saved, viewed or on sent there. Unlike an IP camera (which connects using Ethernet or Wi-Fi), a webcam is generally connected by a USB cable, or similar cable, or built into computer hardware, such as laptops.

The term "webcam" (a clipped compound) may also be used in its original sense of a video camera connected to the Web continuously for an indefinite time, rather than for a particular session, generally supplying a view for anyone who visits its web page over the Internet. Some of them, for example, those used as online traffic cameras, are expensive, rugged professional video cameras.

Webcam model

A webcam model (colloquial gender-neutral: camodel; female: camgirl; male: camboy) is a video performer who is streamed upon the Internet with a live webcam broadcast. A webcam model often performs erotic acts online, such as stripping, in exchange for money, goods, or attention. They may also sell videos of their performances. Since many webcam models operate from their homes, they are free to choose the amount of sexual content for their broadcasts. While most display nudity and sexually provocative behavior, some choose to remain mostly clothed and merely talk about various topics while still soliciting payment as tips from their fans.

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