title: Graphics processing unit

text: "Integrated graphics processing unit" (IGPU), "Integrated graphics", "shared graphics solutions", "integrated graphics processors" (IGP) or "unified memory architecture" (UMA) utilize a portion of a computer's system RAM rather than dedicated graphics memory. IGPs can be integrated onto the motherboard as part of the (northbridge) chipset, or on the same die (integrated circuit) with the CPU (like AMD APU or Intel HD Graphics). On certain motherboards, AMD's IGPs can use dedicated sideport memory. This is a separate fixed block of high performance memory that is dedicated for use by the GPU. In early 2007, computers with integrated graphics account for about 90% of all PC shipments. They are less costly to implement than dedicated graphics processing, but tend to be less capable. Historically, integrated processing was considered unfit to play 3D games or run graphically intensive programs but could run less intensive programs such as Adobe Flash. Examples of such IGPs would be offerings from SiS and VIA circa 2004. However, modern integrated graphics processors such as AMD Accelerated Processing Unit and Intel Graphics Technology (HD, UHD, Iris, Iris Pro, Iris Plus, and Xe-LP) are more than capable of handling 2D graphics or low stress 3D graphics.


title: Graphics processing unit

text: Since the GPU computations are extremely memory-intensive, integrated processing may find itself competing with the CPU for the relatively slow system RAM, as it has minimal or no dedicated video memory. IGPs can have up to 29.856 GB/s of memory bandwidth from system RAM, whereas a graphics card may have up to 264 GB/s of bandwidth between its RAM and GPU core. This memory bus bandwidth can limit the performance of the GPU, though multi-channel memory can mitigate this deficiency. Older integrated graphics chipsets lacked hardware transform and lighting, but newer ones include it.


title: Graphics processing unit

text: This newer class of GPUs competes with integrated graphics in the low-end desktop and notebook markets. The most common implementations of this are ATI's HyperMemory and Nvidia's TurboCache.


title: Graphics processing unit

text: Hybrid graphics cards are somewhat more expensive than integrated graphics, but much less expensive than dedicated graphics cards. These share memory with the system and have a small dedicated memory cache, to make up for the high latency of the system RAM. Technologies within PCI Express can make this possible. While these solutions are sometimes advertised as having as much as 768 MB of RAM, this refers to how much can be shared with the system memory.


title: Graphics processing unit

text: It is becoming increasingly common to use a general purpose graphics processing unit (GPGPU) as a modified form of stream processor (or a vector processor), running compute kernels. This concept turns the massive computational power of a modern graphics accelerator's shader pipeline into general-purpose computing power, as opposed to being hardwired solely to do graphical operations. In certain applications requiring massive vector operations, this can yield several orders of magnitude higher performance than a conventional CPU. The two largest discrete (see "Dedicated graphics cards" above) GPU designers, AMD and Nvidia, are beginning to pursue this approach with an array of applications. Both Nvidia and AMD have teamed with Stanford University to create a GPU-based client for the Folding@home distributed computing project, for protein folding calculations. In certain circumstances, the GPU calculates forty times faster than the CPUs traditionally used by such applications.


title: Graphics processing unit

text: GPGPU can be used for many types of embarrassingly parallel tasks including ray tracing. They are generally suited to high-throughput type computations that exhibit data-parallelism to exploit the wide vector width SIMD architecture of the GPU.


title: Graphics processing unit

text: Furthermore, GPU-based high performance computers are starting to play a significant role in large-scale modelling. Three of the 10 most powerful supercomputers in the world take advantage of GPU acceleration.


title: Graphics processing unit

text: GPUs support API extensions to the C programming language such as OpenCL and OpenMP. Furthermore, each GPU vendor introduced its own API which only works with their cards, AMD APP SDK and CUDA from AMD and Nvidia, respectively. These technologies allow specified functions called compute kernels from a normal C program to run on the GPU's stream processors. This makes it possible for C programs to take advantage of a GPU's ability to operate on large buffers in parallel, while still using the CPU when appropriate. CUDA is also the first API to allow CPU-based applications to directly access the resources of a GPU for more general purpose computing without the limitations of using a graphics API.


title: Graphics processing unit

text: Since 2005 there has been interest in using the performance offered by GPUs for evolutionary computation in general, and for accelerating the fitness evaluation in genetic programming in particular. Most approaches compile linear or tree programs on the host PC and transfer the executable to the GPU to be run. Typically the performance advantage is only obtained by running the single active program simultaneously on many example problems in parallel, using the GPU's SIMD architecture. However, substantial acceleration can also be obtained by not compiling the programs, and instead transferring them to the GPU, to be interpreted there. Acceleration can then be obtained by either interpreting multiple programs simultaneously, simultaneously running multiple example problems, or combinations of both. A modern GPU can readily simultaneously interpret hundreds of thousands of very small programs.


title: Graphics processing unit

text: Some modern workstation GPUs, such as the Nvidia Quadro workstation cards using the Volta and Turing architectures, feature dedicating processing cores for tensor-based deep learning applications. In Nvidia's current series of GPUs these cores are called Tensor Cores. These GPUs usually have significant FLOPS performance increases, utilizing 4x4 matrix multiplication and division, resulting in hardware performance up to 128 TFLOPS in some applications. These tensor cores are also supposed to appear in consumer cards running the Turing architecture, and possibly in the Navi series of consumer cards from AMD.


title: Graphics processing unit

text: An external GPU is a graphics processor located outside of the housing of the computer, similar to a large external hard drive. External graphics processors are sometimes used with laptop computers. Laptops might have a substantial amount of RAM and a sufficiently powerful central processing unit (CPU), but often lack a powerful graphics processor, and instead have a less powerful but more energy-efficient on-board graphics chip. On-board graphics chips are often not powerful enough for playing video games, or for other graphically intensive tasks, such as editing video or 3D animation/rendering.


title: Graphics processing unit

text: Therefore, it is desirable to be able to attach a GPU to some external bus of a notebook. PCI Express is the only bus used for this purpose. The port may be, for example, an ExpressCard or mPCIe port (PCIe ×1, up to 5 or 2.5 Gbit/s respectively) or a Thunderbolt 1, 2, or 3 port (PCIe ×4, up to 10, 20, or 40 Gbit/s respectively). Those ports are only available on certain notebook systems. eGPU enclosures include their own power supply (PSU), because powerful GPUs can easily consume hundreds of watts.


title: Graphics processing unit

text: Official vendor support for external GPUs has gained traction recently.  One notable milestone was Apple's decision to officially support external GPUs with MacOS High Sierra 10.13.4.  There are also several major hardware vendors (HP, Alienware, Razer) releasing Thunderbolt 3 eGPU enclosures. This support has continued to fuel eGPU implementations by enthusiasts.


title: Buick

text: Buick () is a division of the American automobile manufacturer General Motors (GM). Started by automotive pioneer David Dunbar Buick in 1899, it was among the first American marques of automobiles, and was the company that established General Motors in 1908. Before the establishment of General Motors, GM founder William C. Durant had served as Buick's general manager and major investor.


title: Buick

text: In the North American market, Buick is a premium automobile brand, selling luxury vehicles positioned above GM's mainstream brands, while priced below the flagship luxury Cadillac division. Buick's current target demographic according to "The Detroit News" is "a successful executive with family."


title: Buick

text: After securing its market position in the late 1930s, when junior companion brand Marquette and Cadillac junior brand LaSalle were discontinued, Buick was positioned as an upscale luxury car below the Cadillac. During this same time period, many manufacturers were introducing V8 engines in their high-end models, while Buick used a straight-8 for all models starting in 1931. The first Buick V8 was introduced in 1953, then in 1962, the Buick V6 was introduced for the compact Special model. Buick engines, with few exceptions, have always used overhead valves which the company pioneered in the 1904 Buick Model B.


title: Buick

text: In 2017, Buick sold more than 1.4 million vehicles worldwide, a record for the brand. Buick's largest market is China, which accounts for 80% of its sales. Buicks are also sold in the United States, Canada, and Mexico. U.S. market share in 2022 was 1.2%, down by nearly half of its market share in 2000.


title: Buick

text: Buick is one of the oldest automobile brands in the world and currently the oldest in the United States. (Autocar, founded in 1897, is the oldest motor vehicle manufacturer in the western hemisphere; while originally an automobile maker, Autocar now builds heavy trucks. Oldsmobile, also an early automaker founded in 1897, is now defunct; Studebaker was founded in 1852, but did not begin producing automobiles until 1902; Henry Ford produced his first car in 1896 but did not start the Ford Motor Co. until 1903, and during the period in between was involved with other automobile manufacturers such as Cadillac, founded in 1902).


title: Buick

text: The first two Buick automobiles were made in 1899 and 1900 at the "Buick Auto-Vim and Power Company" by chief engineer Walter Marr, but company owner David Dunbar Buick was reluctant to begin making automobiles, being satisfied with stationary and marine engine production, so Marr left Buick in 1901 to found his own automobile company under his own name. His replacement was Eugene Richard, who applied for a patent in 1902 for Marr's valve-in-head (overhead valve) engine, which patent, number 771,095, was awarded to Richard in the name of Buick in 1904. In 1903, the third Buick automobile was made, this time by Richard, but in 1904 Buick, whose company was now called "Buick Motor Company", moved from Detroit to Flint, Michigan, and Richard stayed behind. Marr was rehired in Flint as chief engineer, to begin making automobiles in production. That year, 37 Buick automobiles were made, production increasing to 750 in 1905, 1,400 in 1906, 4,641 in 1907, and 8,800 in 1908, taking the number one spot away from close competitors Oldsmobile, Ford, and Maxwell.


title: Buick

text: David Buick incorporated his company as the Buick Motor Company on May 19, 1903, in Detroit, Michigan. Buick had been financed by a friend and fellow automobile enthusiast, Benjamin Briscoe, who in September 1903 sold control of the business to James H. Whiting, of Flint Wagon Works, in Flint, Michigan. Whiting moved Buick to Flint, to a location across the street from his factory, with the idea of adding Buick's engines to his wagons. David Buick stayed on as a manager and re-hired Walter Marr as chief engineer. The engine Buick and Marr developed for this automobile was a two-cylinder valve-in-head engine of 159 cubic inches, with each cylinder horizontal and opposed to the other by 180 degrees.


title: Buick

text: Whiting built only a few automobiles in 1904, the Model B, before running out of operating capital, causing him to bring in William C. Durant that year as controlling investor. Durant built a few more model B's in 1904, stepped up production for the model C in 1905, and spent the next four years turning Buick into the biggest-selling automobile brand in the US.


title: Buick

text: During the 19th century, Durant had made his fortune as co-owner, also in Flint, with Josiah Dallas Dort, of the Durant-Dort Carriage Company, which by 1904 was the largest carriage-making company in the country and one of the largest in the world. Durant moved most Buick production to the former Durant-Dort Imperial Wheel plant in Jackson, Michigan in 1905. Buick continued car production in Jackson through 1907, when Factory #1 was completed in Flint. The Jackson plant continued production with Buick trucks through 1912. David Buick sold his stock upon departure in 1906, making him a wealthy man, but he died in modest circumstances 25 years later. In 1907, Durant agreed to supply motors to R. S. McLaughlin in Canada, an automaker, and in 1908 he founded General Motors.


title: Buick

text: Between 1899 and 1902, two prototype vehicles were built in Detroit, Michigan by Walter Lorenzo Marr. Some documentation exists of the 1901 or 1902 prototype with tiller steering similar to the Oldsmobile Curved Dash.


title: Buick

text: In mid-1904, another prototype was constructed for an endurance run, which convinced Whiting to authorize production of the first models offered to the public. The architecture of this prototype was the basis for the Model B.


title: Buick

text: The first Buick made for sale, the 1904 horizontally opposed 2-cylinder engine Model B, was built in Flint, Michigan at a re-purposed factory that was known as the Flint Wagon Works. There were 37 Buicks made that year, none of which survive. There are, however, two replicas in existence: the 1904 endurance car, at the Buick Gallery & Research Center in Flint, and a Model B assembled by an enthusiast in California for the division's 100th anniversary. Both of these vehicles use various parts from Buicks of that early era, as well as fabricated parts. These vehicles were each constructed with the two known surviving 1904 engines.


title: Buick

text: The early success of Buick is attributed mainly to what it called the valve-in-head engine, now known as the overhead valve (OHV), engine patented by Eugene Richard and developed by Richard, Buick, and Marr. The Model F had a two-cylinder engine, an 87-inch wheelbase and weighed 1,800 lbs. The creation of General Motors is attributed mainly to the success of Buick, so it can be said Marr and Richard's designs directly led to GM. The power train and chassis architecture introduced on the Model B was continued through the 1909 Model F.


title: Buick

text: The Model F was similar to the Model G, a lower-priced two-seat roadster, produced from 1906 until 1909. Both the F and G were powered by a two-cylinder 159 engine producing along with a 2-speed transmission as well as mechanical brakes on the rear wheels.


title: Buick

text: The flat-twin engine is inherently balanced, with torque presented to the chassis in a longitudinal manner. The engine was mounted amidships.


title: Buick

text: Billy Durant was a promoter, and Buick soon became the largest carmaker in America. Durant embarked on a series of corporate acquisitions, calling the new firm General Motors. At first, the manufacturers comprising General Motors competed against each other, but Durant ended that. He wanted each General Motors division to target one class of buyers. Buick was positioned below the Cadillac brand. To save on resources, Buick vehicles shared a common platform, called the GM A platform, that was shared with Chevrolet, Oakland, Oldsmobile, and Cadillac.


title: Buick

text: At first, Buick followed the likes of Napier in automobile racing, winning the first-ever race held at Indianapolis Motor Speedway.


title: Buick

text: The first full-size Buick to join the smaller Model B was in 1907, when the Buick Model D was introduced with a four-cylinder T-head engine, installed in the front with rear-wheel drive. This was one of the only cars with side valves that Buick ever made.


title: Buick

text: In 1910, Buick introduced the Model 10 with an OHV four-cylinder engine followed in 1911, with their first closed-body car, the Buick Six, that followed the same bodystyle that first appeared at Cadillac, and four years ahead of Ford. The car was built at the all-new factory in Flint which later became known as Buick City. Buick during the 1920s made various sized vehicles, with series designations for different years, sometimes using numbers, while later years using lettered designations. One of the larger vehicles, with straight-six, was the Buick Master Six.


title: Buick

text: In the 1910s and 1920s, Buick was a prestige brand in the Republic of China with the brand driven by or for high-level politicians and the Emperor. Buick now sells 80% of its production in the People's Republic of China and is a minor player in Taiwan.


title: Buick

text: In 1929, as part of General Motors' companion make program, Buick Motor Division launched the Marquette sister brand, designed to bridge the price gap between Buick and Oldsmobile; however, Marquette was discontinued in 1930. All Buick, Marquette, Viking, and Oldsmobile products shared the newly introduced GM B platform starting in 1926.


title: Buick

text: Buick debuted two major achievements for the 1931 model year, the OHV Buick Straight-8 engine and a synchromesh transmission in all models but the Series 50. The Eight was offered in three displacements, the 220 cubic inch (bore 2 7/8 in. stroke 4.25 in.), was available in the Series 50 with 77 brake HP. The Series 60 engine was a 272 cu. in. unit (bore 3 1/16 in., stroke 5 in.) giving 90 brake HP. Cadillac had previously introduced the Cadillac Type 51 with a flathead V8 engine in 1915 which made usage of an eight-cylinder engine a luxury feature.


title: Buick

text: The Series 80 and Series 90 used a 344 cu. in. version (bore 3 5/16 in., stroke 5 in.) for 104 brake HP. Automatic vacuum-operated spark advance was another feature replacing the steering column-mounted spark lever although an emergency lever was now dash mounted. Buick scored another first in 1939 when it became the first company to introduce turn signals, which did not appear on other car brands until almost a decade later. All 1939 models also had a steering column-mounted shift lever.


title: Buick

text: In the mid-1930s McLaughlin-Buicks were purchased by British monarch Edward VIII. He had a preference for the Canadian built McLaughlin-Buick. Buicks were used for royal transport within Canada, including for King George VI and Queen Elizabeth during the 1939 royal tour of Canada.


title: Buick

text: In the 1920s and 1930s Cadillac and Buick vehicles were popular with long-distance passenger service operators e.g. the Nairn Transport Company in the Middle East (Baghdad-Damascus).


title: Buick

text: 1907–1924. Four cylinders, in line, OHV, 165 to 392.6 cu. in. It was related to the Chevrolet Inline-4 engine


title: Buick

text: 1940 saw the first use of the "Estate" designation for Buick on the Super station wagon. World War II stopped automobile production in 1942. Starting that year, Buick produced the M18 Hellcat tank destroyer and supplied radial engines for the B-24 Liberator, Douglas C-47 Skytrain, and Douglas C-54 Skymaster. By the fall of 1945, automobile production resumed. In 1948, the Dynaflow automatic transmission was first offered by Buick. 1949 saw the debut of Buick's VentiPorts.


title: Buick

text: 1953 marked Buick's 50th anniversary as well as the introductions of the Buick V8 engine and the Roadmaster Skylark. In 1955, Buick had its best model year sales to date with 738,814 vehicles sold; a record that would hold until 1977. In 1957, Buick's new 364 cu. in. engine block and ball joint front suspension debuted and Roadmasters now had aluminum finned brake drums. 1959 saw the introduction of three new models: Electra, Invicta and LeSabre as well as a new 401 cu. in. V8 engine in the Electra and Invicta. An Electra also paced the Indianapolis 500 race that year.


title: Buick

text: An Electra 225 paced the Daytona 500 race in both 1960 and 1963. In 1961, a new Fireball V6 engine was introduced and the Skylark nameplate returned as the top model of the new Special compact car line. The Buick Special was named Motor Trend Car of the Year in 1962. Also in 1962, Wildcat was introduced as a trim level on Invicta and became its own model the following year. In 1963 the Riviera was introduced as its own model. In the mid-1960s Buick started officially selling German-built Opel cars through its North American dealerships. For 1967, radial tires became available as an option on all full-size Buicks.


title: Buick

text: The 1970s saw a number of new models added to the Buick lineup including the Estate Wagon as its own model in 1970, Centurion in 1971, Apollo in 1973, and Skyhawk in 1975. 1975 also saw the first appearance of the "Park Avenue" nameplate for Buick as a trim/option package on the Electra 225 Limited. A Buick Century paced the Indianapolis 500 race not once but twice in the mid-1970s. For 1976, Buick began selling rebadged Isuzu Geminis as Opels to replace the Opel Kadett models it had previously marketed. The following year, Electra 225 and LeSabre were redesigned and downsized and the Buick brand saw its best model year sales to date with 773,313 vehicles sold. 1978 marked Buick's 75th anniversary and welcomed a redesigned Century as well as a redesigned Regal coupe which was now available with a turbocharged V6 engine. Buick model year sales broke another record in 1978 with 795,316 vehicles sold. For 1979, the Riviera was redesigned; Riviera S-Type was named Motor Trend Car of the Year.


title: Buick

text: In the 1980s, Buick's lineup saw several changes including the downsizing of various models. In 1980, Lloyd Reuss was appointed as general manager and further pushed Buick into turbocharging, racing, and performance production cars, building momentum which continued a number of years after his departure in 1984 as he headed toward a brief term as GM president. Also in 1980, the Diesel engine becomes available on select Buick models and Somerset is introduced as a trim/option package on the Regal Limited. In 1981, the T-Type performance trim is introduced on the Riviera. Regal was the official pace car of the Indianapolis 500 race in 1981. In 1982, the Grand National high-performance package is first offered on Regal. A soft-top Riviera helped lead the return of the convertible, which had disappeared from domestic lineups in 1976. The following year, a Riviera convertible with a twin-turbo V6 paced the Indy 500. Also in 1983, Buick had its best model year to date with 810,435 vehicles sold.


title: Buick

text: In 1984, Buick was the official car of the XXIII Olympiad. A reorganization split manufacturing & engineering from sales and marketing. The first pilot Buick is produced at "Buick City", a state-of-the-art assembly center built inside the walls of Buick's home plant at Flint. Buick had its best model year sales to date with 906,626 vehicles sold plus Buick's worldwide sales topped one million for the first time. Lloyd Reuss ended his tenure as general manager of the Buick Motor Division in 1984.


title: Buick

text: In 1985, the Somerset was introduced as its own model. Also, the Electra coupe and sedan were redesigned and converted to front-wheel drive and were initially powered by a carbureted 3.0 liter Buick V6 engine, a fuel-injected 3.8 liter Buick V6 engine, or a 4.3 liter Oldsmobile diesel V6 engine. Each was mated to a 4-speed automatic transmission with a 0.70:1 overdrive gear. The 3.0 liter V6 and 4.3-liter diesel V6 were no longer offered after 1985. During the 1985 to 1989 model years, the Electra name also continued to be used on the rear-wheel-drive B-body "Estate" station wagon. Buick-powered cars won pole and second position in qualifying for Indianapolis 500. Over the next few years, Buick engines would set a number of stock-block records and twice would power a third or more of the 33-car Indy 500 field (11 in 1990 and 12 in 1992). 1985 would be the final year for the rear-drive LeSabre before another downsizing and conversion to front-wheel-drive for 1986 (sedans and coupes only; the rear-drive LeSabre Estate Wagon would soldier on largely unchanged a few more years). The top-line LeSabre Limited became the LeSabre Limited Collectors Edition to mark the end of an era for the rear-wheel-drive coupe and sedan; engine offerings included the standard 231 V6 (sedans and coupes) or optional Olds 307 V8 or Oldsmobile 350 diesel V8. 1985 saw Buick's best model year sales to date with 915,336 vehicles sold.


title: Buick

text: In 1986, the LeSabre was introduced on the new front wheel drive H platform, after departing from rear wheel drive on the GM B platform. Joining the LeSabre on the H-body included the Oldsmobile Delta 88. The new LeSabre's hood was hinged at the front of the car instead of near the cowl and windshield. The new styling and front-wheel drive also did not include Buick's long-standing Ventiports on the front fenders. In 1986, a LeSabre Grand National model was built to qualify the coupe body style for NASCAR competition. Less than 120 units were made, all finished in black with a gray interior.


title: Buick

text: Also for 1986, the E-body Riviera was converted to unibody construction and further downsized to a wheelbase similar in length to that of the Buick Regal. The V6 was now the only engine, rated initially at SAE and of torque. It used the Turbo-Hydramatic 440-T4 automatic with a 2.84:1 final drive ratio. This generation was noted for advanced electronic instrumentation displayed on a dash-mounted CRT. The CRT controlled the vehicle's climate control system and stereo, and also supplied advanced instrumentation such as a trip computer and maintenance reminder feature. Four-wheel disc brakes were standard. With a choice of three suspension packages available, up to the performance-oriented FE3 setting, handling was notably improved. The Riviera placed fourth for "Motor Trend"s 1986 Car of the Year contest. Fuel economy was notably improved for the 1986 Riviera, but the investment in the downsized, transverse engine front-wheel drive platform resulted in a substantial price increase to $19,831 for the base model to $21,577 for the new T-Type. Downsizing also resulted in a dimensional similarity to smaller, less expensive offerings from GM. The smaller dimensions, generic styling, and lack of a V8 led to Riviera sales plummeting to 22,138 for 1986.


title: Buick

text: In 1987, the last of the turbo/intercooled Regal Grand Nationals, often called the quickest American cars, were offered as well as 547 even quicker special-edition '87 GNXs. It would also be the last year for the rear-wheel-drive Regal. General manager Ed Mertz promoted the new "Premium American Motorcars" theme which focused Buick marketing on the various qualities that made the marque famous.


title: Buick

text: In 1988, Buick was the official car of the U.S. Olympic Team. The Reatta two-seater was introduced, to be followed two years later by a convertible. Also in 1988, Regal was downsized and converted to front-wheel drive. Bobby Allison won the Daytona 500 in a Regal that year. 1988 also saw the debut of the slogan "The Great American Road Belongs to Buick".


title: Buick

text: In 1989, a new Electra trim level was offered called the Park Avenue Ultra. The Ultra was an upgrade to the Electra Park Avenue and featured a standard leather-trimmed interior with dual 20-way power front seats (shared with Cadillac's restyled 1989 Fleetwood Sixty Special), lower-body accent exterior paint treatment, distinctive thick-padded vinyl top with limousine-style rear-window surround (available only on Ultra), simulated burled elm trim on the doors and instrument panel, unique aluminum wheels, anti-lock brakes, chromed B-pillar moldings, specific grille and tail lamps, leather-wrapped steering wheel, electronic instrumentation, padded glove-compartment door, unique interior door panel trim, and a variety of otherwise minor changes. With its long list of standard equipment, the Park Avenue Ultra carried a higher base price than Cadillac's Sedan de Ville. The Riviera was also restyled for 1989, adding 11 inches to its overall length. In the late 1980s, the Flint-built LeSabre ranked #1 in North America and #2 in the world in a major independent quality study which eventually led Buick to change its ad slogan from "The Great American Road Belongs to Buick" to "Buick: The New Symbol for Quality in America."


title: Buick

text: In 1990, the first Reatta convertible was produced. 1990 was also the last year for the Electra as Park Avenue, previously a trim level on the Electra, became its own model for the 1991 model year. In 1991, Buick led the industry in improvement in sales and market share. A new four-door Regal came to market for 1991, the first Regal sedan since 1984. Buick also introduced a supercharged 3.8-liter V6 in the Park Avenue Ultra. Supercharging became so popular at Buick that by the new millennium, Buick was the leading marketer and industry leader of supercharged cars. 1991 saw the return of the Roadmaster after a 33-year absence. The Roadmaster was first offered as a wagon only and then a sedan was added for 1992.


title: Buick

text: For 1992, the popular LeSabre was redesigned along the same lines as the previous year's Park Avenue. 1992 also saw the introduction of a new, redesigned Skylark. In 1993, a special edition LeSabre was sold to commemorate Buick's 90th anniversary. In addition to Custom trim level standard equipment, included were "90th Anniversary" badging, cassette player, cruise control, rear-window defogger, power driver's seat, carpeted floor mats, exterior pinstripes, and choice of wire or aluminum wheel covers.


title: Buick

text: In 1995, after a hiatus in 1994, the Riviera returned with radical styling that departed from the previous generations' more traditional image. A naturally aspirated 3800 V6 was standard, with a supercharged version rated at and available as an option. Rivieras were now built in Lake Orion, Michigan, riding the same Cadillac-derived G platform as the 4-door Oldsmobile Aurora.


title: Buick

text: In 1996, both the Roadmaster sedan and wagon were discontinued. In 1998, after 95 years in Flint, Buick headquarters was moved to Detroit. Bob Coletta, Buick general manager, saw the first Chinese Buick roll off line at Shanghai before he turned over the top Buick job to Roger Adams. Buick Gallery and Research Center opened at Flint's Sloan Museum. A reorganization of the division split sales from marketing.


title: Buick

text: In 1999, the last of nearly 16 million Buicks was built in Flint's Buick City. The last car, a 1999 LeSabre, rolled off the assembly line on June 29 that year. In a major independent quality study, Buick ranked #2 (and top domestic) among 37 international brands and Buick City shared top world position among automotive assembly plants. With sales of all coupes declining in the North American market, GM decided to discontinue the Riviera. 1999 was the car's last model year with production ceasing on November 25, 1998. The final 200 cars had special silver paint and trim, and were denoted "Silver Arrow" models, a designation which hearkened back to several Silver Arrow show cars that had been built off Riviera bodies by Bill Mitchell. The eighth-generation Rivieras received the most powerful V6 Buick engine since the Grand Nationals of the 1980s. The supercharged OHV V6 gave impressive torque and acceleration, pushing the car from 0 to in under 7 seconds, and turning the mile in 15.5 seconds and achieved MPG fuel efficiency ratings of 18 city/27 highway.


title: Buick

text: In the 2000s, Buick's lineup was modified with the compact and performance segments being abandoned in favor of the crossover/SUV market which was growing in popularity. In 2000, Buick headed into the new millennium with a redesigned LeSabre (best-selling U.S. full-size car for eight straight years) and a more powerful Century. Since the first Detroit experimental car of 1899–1900 and the first Flint production car of 1904, more than 35 million Buicks had been built. The 2000 LeSabre was introduced in March 1999 and was now built on GM's G platform; however GM chose to continue to refer to it as the H platform. The LeSabre was manufactured at GM's Detroit/Hamtramck Assembly factory in Hamtramck, Michigan and Lake Orion Assembly, in Lake Orion, Michigan. Some of the changes with the redesign included a new grille that did not open with the hood and slightly smaller exterior dimensions. Despite its somewhat smaller exterior size, it still offered similar interior room and more trunk space than the previous model. 2001 saw Buick's first entry into the crossover market with the introduction of the Rendezvous as a 2002 model. In 2003, the Buick Centieme crossover concept car commemorated Buick Motor Division's 100th anniversary. Some of the Centieme's exterior design and interior features would later appear on the 2008 Enclave crossover. In 2004, Buick added the Rainier mid-size SUV and the new Terraza minivan was added a year later.


title: Buick

text: In the years following, Buick began consolidating its North American lineup and by 2008 had reduced it to just three models: the LaCrosse/Allure, the Lucerne, and the new-for-2008 Enclave. The Super name had also returned after a 50-year absence as a new performance trim level on LaCrosse and Lucerne. The brand's total overall sales slipped in the United States, and, with a reputation for primarily appealing to older buyers, rumors circulated throughout this decade that the Buick marque would be discontinued. The profitability of the model lineup and popularity in China ensured Buick's future within General Motors, with the decision being made to discontinue the Pontiac brand instead.


title: Buick

text: Since 2005, GM had gradually consolidated Buick with GMC and former Pontiac dealerships to create the current Buick-GMC network. During General Motors Chapter 11 reorganization and emergence in 2009, the company designated Buick as a "core brand", citing the division's success in China. Behind the scenes, GM began to move products originally planned for other brands to Buick. The Opel Insignia was originally intended to become the second-generation Saturn Aura, but instead became the new Buick Regal. In the 2009 J.D. Power and Associates Vehicle Dependability Study, Buick tied with Jaguar as the most dependable brand in the United States.


title: Buick

text: The 2010s saw the return of a classic Buick nameplate. The Buick Regal, as well as the addition of several new ones. The decade also saw the brand's first hatchback since 1987, its first factory convertible since 1991, and its first station wagon since 1996. Buick further expanded its presence in the popular crossover/SUV market in the 2010s as well.


title: Buick

text: In January 2009, Buick unveiled the new 2010 LaCrosse sedan, an all-new styling direction that included traditional Buick cues. The market responded positively to the LaCrosse and reviews favorably compared it luxury models such as the Lexus ES. In 2010, Buick became the fastest-growing automotive brand in America and attracted a younger customer demographic. A GM company spokesman at the time said that Buick was positioned as a "premium" marque (entry-level luxury) to compete with various Acura, Infiniti, Lexus, and Volvo models, while Cadillac was aimed at the "luxury" performance segment which includes brands like BMW and Mercedes-Benz. An all-new Regal sedan, a smaller model based on the European Opel Insignia, was re-introduced for the 2011 model year after a seven-year absence. For 2012, the all-new Verano, which was a compact sedan based on the Chevrolet Cruze, joined the lineup. Additionally, the performance-oriented Regal GS officially went on sale and became the first Buick in almost 20 years to be offered with a manual transmission and a turbocharger. Buick also entered the hybrid market with the introduction of eAssist technology on the 2012 LaCrosse and Regal which helped improve fuel economy ratings by as much as 38% over the regular gas-engine versions. Meanwhile, sales of the Enclave crossover remained strong. In January 2012, the all-new Encore mini crossover was unveiled at the North American International Auto Show in Detroit. Also in 2012, a turbocharged version of the Verano was introduced and the Enclave was redesigned for the 2013 model year. In 2013, GM confirmed plans of a "hybrid global brand" which includes Opel/Vauxhall and Buick using more synergies between the brands. LaCrosse and Regal were refreshed for the 2014 model year. In 2015, the all-new Cascada subcompact convertible debuted at the North American International Auto Show in Detroit. The all-new 2017 LaCrosse was shown at the Los Angeles Auto Show in November. Buick also confirmed that the Envision compact crossover would be sold in North America starting summer 2016. The Verano compact sedan was dropped from the Buick lineup in North America in 2017. With GM selling off the Opel/Vauxhall division to Group PSA in March 2017, Buick is expected to move away from sharing Opel model/designs upon the completion of the current generation vehicles.


title: Buick

text: For 2018, Buick replaced the Regal sedan with an all-new model offering hatchback and station wagon body styles. This new Regal was the first hatchback from Buick for the North American market since the 1987 Skyhawk and the first station wagon since the 1996 Roadmaster. A sub-brand was also added in 2018 to accompany Buick, with the Avenir badge being applied to its top-of-the-line level trims, utilizing the same strategy as GMC's successful Denali sub-brand. 2019 would be the last year for the Cascada convertible globally and the LaCrosse sedan for the North American market.


title: Buick

text: New for 2020 was the Encore GX crossover which slotted in between the existing Encore and Envision. The Regal hatchback and station wagon were discontinued for the North American market in 2020.


title: Buick

text: In June, 2022, Buick Global Chief Duncan Aldred announced that Buick would transition its entire line-up to electric vehicles by 2030. As part of that plan, all Buick dealers would be given the opportunity to take a buyout rather than switch to all electric. Aldred explained the move saying that making the transition to electric would require a considerable investment in upgrading dealer facilities and not all dealers would be willing to make the financial commitment. Aldrerd also pointed out that most Buick dealers also sold other GM products, so accepting the buyout would not necessarily result in a dealership closing. Once Buick's top selling model in the North America, the Encore was discontinued in 2022 as more customers favored the larger Encore GX which was introduced for 2020 and became Buick's new top seller.


title: Buick

text: Buick has a long history of creating intriguing concept cars dating back to the Y-Job, the industry's first concept car, of 1938. Its most recent concepts, all electric vehicles, are the Buick Enspire concept unveiled in April 2018, the Buick Electra concept unveiled in September 2020, and the Buick Wildcat concept which was unveiled in June 2022.


title: Buick

text: The Buick Trishield is rooted in the ancestral coat of arms of the automaker's founder, David Dunbar Buick. That crest was a red shield with a checkered silver and azure diagonal line from the upper left to lower right, a stag above, and a punctured cross below. The division adopted this on its radiator grilles in 1937. In 1960, the logo underwent a major overhaul. Its single shield was replaced by a trio in red, white, and blue—denoting the LeSabre, Invicta, and Electra then in the Buick lineup. It was supplanted by the Buick Hawk in the 1970s, but the trishield reemerged in the 1980s, simplified, but with its same patriotic colors. The Trishield with red, white, and blue features, was simplified in 2005, but the colors have returned, representing the current trio of vehicles in the Buick marque for sedans and crossovers.


title: Buick

text: A traditional Buick styling cue dating to 1949 is a series of three or four 'vents' on the front fenders behind the front wheels. The source of this design feature was a custom car of Buick stylist Ned Nickles, which in addition had a flashing light within each hole, each synchronized with a specific spark plug to simulate the flames from the exhaust stack of a fighter airplane. Combined with the bombsight mascot (introduced in 1946), Nickle's custom Buick invoked an imaginary fighter airplane. The flashing light feature was not used by Buick in production.


title: Buick

text: The 1949 Buick Sales brochure stated the following "...four chrome-ringed Venti-Ports on forward fenders (three on all Super models) striking a smart aviation note while serving to ventilate the engine compartment." Air entered from the grille into the engine bay, was pressurized by the radiator fan and exited (partially) through the VentiPorts. However, sometime during the 1949 model year this attribute was discontinued and the VentiPorts became non-functional.


title: Buick

text: When introduced in 1949, there were only 2 model lines; the higher-priced Roadmaster had 4 ports per side, the lower series Super had 3. This was echoed over the next few years. By '54, Buick had added the Special and Century model lines, and although the Century and Super both used the same engine as the top-line Roadmaster, only the Roadmaster wore 4 VentiPorts. And the '53-54 Skylark had none.


title: Buick

text: Buick was not entirely consistent with how they applied the styling feature, so theories that their count was tied to engine or body shell size is not factually consistent. It is more accurate that Buick tied the Ventiport count to the model line, and that was dependent on the year in question. For example, in '55 the Century and Super were both 'promoted' to 4 VentiPorts per side, despite the fact that the Century was sharing the smaller body shell with the '3-holer' Special.


title: Buick

text: Buick temporarily dropped the VentiPorts for model years 1958 and 1959. 1958 is infamous for being relatively over-adorned; perhaps stylists decided there wasn't 'room' for Ventiports that year. But by model-year 1960, they were back.


title: Buick

text: In 1961, Buick introduced the first V6 engine installed in an American passenger car, called the Fireball V6 in the Buick Special, and three VentiPorts appeared on the side. This still was not tied to cylinder count, however, as the V8 LeSabres continued to carry 3 Ports per side. Also during this era, Buick used what the '67 Buick GS brochure called "vertical VentiPorts" to describe trim details seen on the lower half of front fenders on the Skylarks and Wildcat lines. The specialty Riviera model had neither, akin to the '53-54 Skylark. VentiPorts were used on most models over the next 2 decades.


title: Buick

text: VentiPorts appeared on the limited production 1987 Buick GNX, and once again they were functional. Then the feature was dropped again, until 2003 when VentiPorts were re-introduced on the Buick Park Avenue Ultra. After the Park Avenue was discontinued, Buick incorporated VentiPorts on the new-for-2006 Lucerne. For the first time, it seemed Buick was tying VentiPort count to the number of cylinders; the V6 Lucernes had three on each side, while V8s had four on each side.


title: Buick

text: Modern and edgy compared to the oval ones that adorned Buicks for years, the new VentiPorts have become a Buick-wide talisman again. The newly designed VentiPorts appear on every Buick model from 2014 until around 2017.


title: Buick

text: At one time, a letter from Buick surfaced that was a response to an inquiry regarding the name of the ports. The official name, according to the letter, was "Cruiserline VentiPorts".


title: Buick

text: Another styling cue from the 1940s through the 1970s was the Sweepspear, a curved trim line running almost the length of the car. Introduced as an option on the 1949 Buick Roadmaster Riviera hardtop coupe, the original Sweepspear was a chrome-plated steel rub strip which began level over the front wheel, gently curved down across the front fender and door, dove nearly to the rocker panel just ahead of the rear wheel, then flared up and over the rear wheel before leveling off again into a straight run back to the tail light.


title: Buick

text: In 1942 all GM vehicles had an appearance upgrade where the trailing edge of the front fender was extended across the front doors that was called "Airfoil" accented by parallel chrome strips on the front and rear fenders on Buick vehicles. In later years the character line of the "Airfoil" feature was accented with a stainless steel strip that evolved into the Buick "Sweepspear" for several decades.


title: Buick

text: The "Riviera trim", as it was initially called, was made available on the Roadmaster convertible very late in the '49 model year. It proved so popular that by the 1951 model year it was made a standard feature on all Buicks. On 1950s models with two-tone paint, the Sweepspear separated the two colors.


title: Buick

text: Originally stainless steel, the Sweepspear eventually became a vinyl rub strip or simple character line in the sheetmetal, as hinted in some versions of the Buick Riviera, distinct on the 1968-1969 Skylark, and appearing on the 2008 Invicta concept car. Often optional trim was available to reinforce a plain character line in the bodywork.


title: Buick

text: The 1958 Buick was marketed beginning in September 1957, just as the space age began with the launching of Sputnik I on October 4 of that year. The "Sweepspear" evolved into the "Delta Fin" reminiscent of a rocket ship, which appeared on the all-new appearance for 1959, and was trimmed down in 1960 and removed for 1961.


title: Buick

text: During the 1950s, the characteristic form of the Buick taillamps was a tier of small, circular bullet-shapes. In the early 1960s, most models began to evolve a wide, rectangular pattern, until the 1965 Skylark and Electra models appeared with full-width rear lamps.


title: Buick

text: The Buick styling cue (dating from the 1942–1958 period) that has most often reappeared, though, is for the grille to be a horizontal oval with many, thin, vertical chromed ribs bulging forward. This has sometimes been called the Buick "dollar grin" particularly on the early 1950s models, which had thick, highly polished ribs that somewhat resembled teeth. The 1950 model took this tooth theme to its extreme as the teeth crossed over the bumper exposing the 1950 "grin", which was the result of extending the bumper guards over the front bumper, and was advertised as "Front and Center with Duty plus Beauty". The 1951 model reined in the theme, bringing the bumper guard "teeth" back behind the bumper. Current Buick Models have a new take on the classic styling with their Chromed "Waterfall Grilles".


title: Buick

text: In recent years, Buick has adopted a waterfall grille, as seen on the Buick Velite concept car from 2004 and first used in production with the Buick Lucerne introduced for the 2006 model year. This waterfall grille bears some resemblance to grilles of Buicks from the 1980s, such as the Grand National.


title: Buick

text: The Buick V8 engine, nicknamed the Nailhead because of its relatively small intake and exhaust valves which resembled nails, became popular with hot-rodders in the 1950s and 1960s because the vertical attachment of the valve covers, in contrast to the angled attachment of other V8 engines, enabled the engine to fit into smaller spaces while maintaining easy access for maintenance.


title: Buick

text: In addition to premium and luxury vehicles, Buick has also been well known for its offerings of high-performance cars. Some of the better-known examples included the Gran Sport and Skylark GSX models of the 1960s and 1970s, and the Grand National and GNX models of the 1980s, with a performance package revival called T-Type.


title: Buick

text: Buick is one of China's most popular, best selling automobiles. In 2016, General Motors sold over 1.1 million Buicks in China. Buicks have always been popular in China. In pre-World War II China, one in five cars was a Buick. Buicks were used by the last emperor Puyi, the first president Sun Yat-sen, and the first premier Zhou Enlai.


title: Buick

text: Since 1999, a Buick Regal for China has been produced and sold by Shanghai GM and has proven to be popular among upscale, professional families, establishing Buick as one of the most popular vehicle brands in China. In addition, Buick of China sells a compact Excelle, similar to a five-door hatchback version called the HRV, and a minivan named the GL8. Many Buicks for the local market are equipped with smaller more fuel-efficient engines with double overhead camshafts, than those with overhead valves in the same nameplate for the American market.


title: Buick

text: GM Taiwan was founded in August 1989. In the early 1990s, Buick, along with other GM brands, was very popular and frequently seen on Taiwanese streets. Park Avenue, 3rd and 4th generation Regal, and 6th generation Skylark used to be sold in Taiwan. In December 2004, General Motors signed a memorandum of understanding with Yulon, a firm based in Taiwan, for the licensed manufacture of Buick vehicles there. In July 2005, Yulon GM Motor Co. Ltd. (Yulon GM), a joint venture with 51 percent equity stake held by Yulon Motor and 49 percent by GM, was founded.


title: Buick

text: In April 2010, Buick debuted a localised version of LaCrosse, named Alpheon, to the South Korean market.


title: Buick

text: Buicks were sold in Mexico from 1921 to 1962, when a protectionist policy on behalf of the government restricted the percentage of imported parts that could be used in the manufacture of vehicles and the sale of imported cars. From then onwards, all GM products were sold by Chevrolet dealerships. In 1990, after a heavy modification to the protectionist policy of the sixties, GM started assembling the Buick Century in Mexico, at the plant in Ramos Arizpe, in the state of Coahuila, just south of Texas, and selling it through Mexican Chevrolet dealerships, so it was not uncommon for many people to call it "Chevrolet Century". In 1997, GM stopped selling Buicks in Mexico and the brand was not sold there until 2009.


title: Buick

text: With the announcement in 2009 of the elimination of the Pontiac brand, it was speculated that Buicks would be sold once again in Mexico since there was a large network of Pontiac-GMC dealerships already in place. On July 24, 2009, Grace Lieblein, the new president of GM in Mexico, revealed that the Buick brand would be available in Mexico in late September of that year, after an absence of a dozen years, with the LaCrosse and the Enclave models. Buick shared the dealership floor with Pontiac and GMC until the Pontiac brand faded away in the summer of 2010.


title: Buick

text: On March 26, 2019, Buick announced that the Mexican division will offer only crossovers (Encore, Envision, and Enclave). The La Crosse sedan, Regal hatchback and Regal TourX station wagon were dropped from the market as those brands are expected to go away due to Opel's future (under new owner PSA) regarding the Insignia that is tied to the North American-badged Regal and Buick's decision to make the La Crosse exclusive to China.


title: Buick

text: In Israel, Buicks are imported by Universal Motors, Ltd. (UMI), which also imports other GM vehicles. For model years 2004 and 2005, the Buick LeSabre and Buick Rendezvous were sold. For model years 2006 and 2007, the Buick LaCrosse and Buick Lucerne were sold alongside the Rendezvous. For model year 2008, the Buick LaCrosse and Buick Lucerne were available. Buicks were sold throughout the Middle East until the second-generation Buick Roadmaster was discontinued, and continued to be available in the Gulf Cooperation Council markets until 1996.


title: Buick

text: Buicks were once sold in New Zealand. They were also built at the GMNZ plant in Petone, outside Wellington. The Buick name was revived helicopter for the New Zealand market.


title: Buick

text: For many years, Buick was a substitute for Chevrolet in automobile racing. No earlier than the 1960s, Buick was a competitor in the Indianapolis 500, and (like almost every other American manufacturer) also participated in the Grand National stock car racing series using its Regal and later the Gran Sport.


title: Buick

text: The golden age of Buick in motorsport, however, was the early to late 1980s. General Motors entered the Regal, particularly the Grand National model, in the NASCAR Cup Series alongside the Oldsmobile Cutlass. Buick was also a major powerplant in the IndyCar Series and IMSA GT Series (particularly in the IMSA GTP class) for several years. The 1990s, however, proved to be the end of Buick's reign in motorsports, as GM replaced it for many years with Oldsmobile before phasing out that marque in 2004. Oldsmobile would be replaced by Pontiac until its demise in 2009, being replaced by Chevrolet.


title: Buick

text: The Buick Club of America, founded in 1966, is a non-profit organization dedicated to the preservation and restoration of automobiles built by the Buick Motor Division of General Motors Corporation.


title: Plague doctor

text: A plague doctor was a physician who treated victims of bubonic plague during epidemics mainly in the 16th and 17th century. These physicians were hired by cities to treat infected patients regardless of income, especially the poor that could not afford to pay.


title: Plague doctor

text: Plague doctors had a mixed reputation, with some citizens seeing their presence as a warning to leave the area or that death was near. Some plague doctors were said to charge patients and their families additional fees for special treatments or false cures. In many cases these doctors were not experienced physicians or surgeons, instead being volunteers, second-rate doctors, or young doctors just starting a career. In one case, a plague doctor was a fruit salesman before his employment as a physician. Plague doctors rarely cured patients, instead serving to record death tolls and the number of infected people for demographic purposes.


title: Plague doctor

text: In France and the Netherlands, plague doctors often lacked medical training and were referred to as "empirics." Plague doctors were known as municipal or "community plague doctors", whereas "general practitioners" were separate doctors and both might be in the same European city or town at the same time.


title: Plague doctor

text: According to Michel Tibayrenc's "Encyclopedia of Infectious Diseases", the first mention of the iconic plague doctor is found during the 1619 plague outbreak in Paris, in the written work of royal physician Charles de Lorme, serving King Louis XIII of France at the time. After De Lorme, German engraver Gerhart Altzenbach published a famous illustration in 1656, which publisher Paulus Fürst’s iconic "Doctor Schnabel von Rom"(1656) is based upon. In this satirical work Fürst describes how the doctor does nothing but terrify people and take money from the dead and dying.


title: Plague doctor

text: The city of Orvieto hired Matteo fu Angelo in 1348 for four times the normal rate of a doctor of 50 florin per year. Pope Clement VI hired several extra plague doctors during the Black Death plague to tend to the sick people of Avignon. Of 18 doctors in Venice, only one was left by 1348: five had died of the plague, and twelve were missing and may have fled away.


title: Plague doctor

text: The need for the elaborate costume came from the belief that the bubonic plaque was transmitted through miasma "poisoned air". Which was a theory from Hippocrates and Galen long before the plaque.


title: Plague doctor

text: Plague doctors practiced bloodletting and other remedies such as putting frogs or leeches on the buboes to "rebalance the humors." A plague doctor's principal task, besides treating people with the plague, was to compile public records of plague deaths.


title: Plague doctor

text: In certain European cities like Florence and Perugia, plague doctors were requested to do autopsies to help determine the cause of death and how the plague affected the people. Plague doctors also sometimes took patients’ last will and testament during times of plague epidemics, and gave advice to their patients about their conduct before death. This advice varied depending on the patient, and after the Middle Ages, the nature of the relationship between doctor and patient was governed by an increasingly complex ethical code.


title: Plague doctor

text: Some plague doctors wore a special costume consisting of an ankle-length overcoat and a bird-like beak mask, often filled with sweet or strong-smelling substances (commonly lavender), along with gloves, boots, a wide-brimmed hat, a linen hood, and an outer over-clothing garment. However, the costume was not worn by all medieval and early modern physicians studying and treating plague patients.


title: Plague doctor

text: The exact origins of the costume are unclear, however have been dated back to Italy and France. Most depictions come from satirical writings and political cartoons. The beaked plague doctor inspired costumes in Italian theatre as a symbol of general horror and death, though some historians insist that the plague doctor was originally fictional and inspired the real plague doctors later. Depictions of the beaked plague doctor rose in response to superstition and fear about the unknown source of the plague. Often, these plague doctors were the last thing a patient would see before death; therefore, the doctors were seen as a foreboding of death.


title: Plague doctor

text: It appears that the only contemporary sources which claim witness to this infamous costume are based in Italy during the 17th century. Later sources based in other areas do claim that this costume was in use in their country (most specifically during the black death), however, it is possible that they are being influenced by theatre and other works of fiction, already cited in this article.


title: Plague doctor

text: The typical mask had glass openings for the eyes and a curved leather beak shaped like a bird's beak with straps that held the beak in front of the doctor's nose. The mask had two small nose holes and was a type of respirator which contained aromatic items. The first known observation of the herbal-stuffed beak was from an the epidemic in Rome in 1656. The beak could hold dried flowers (like roses and carnations), herbs (like lavender and peppermint), camphor, or a vinegar sponge, as well as juniper berry, ambergris, cloves, labdanum, myrrh, and storax. The herbs right up against the nose inside the beak allowed for the doctor to have both of their hands free in order to examine the patient or corpse. The purpose of the mask was to keep away bad smells such as decaying bodies and the smell taken with the most caution was known as miasma or the "poisonous air" which were thought to be the principal cause of the disease. Doctors believed the herbs would counter the "evil" smells of the plague and prevent them from becoming infected.


title: Plague doctor

text: The wide-brimmed leather hat indicated their profession, they used wooden canes in order to point out areas needing attention and to examine patients without touching them. The canes were also used to keep people away and to remove clothing from plague victims without having to touch them. The doctor's long robe was made from linen because it was said germs did not stick to linen as easily as other materials. The robe was also sometimes made from goat skin which was said to be stronger against the plague than linen because of its small pores and polished texture. It was heard of for the robe to be sealed with oil or wax for an extra layer of protection so the "poisoned air" could not seep through the holes of the linen material. The costume of the plague doctor is the one of the first examples we have of a hazmat suit.


title: Plague doctor

text: This well known costume now is used as common costume in festivals mainly in Europe and within the art of theatre.


title: Plague doctor

text: A plague doctor's contract was an agreement between a town's administrators and a doctor to treat bubonic plague patients. These contracts are present in European city archives. Their contractual responsibility was to treat plague patients, and no other type of patient, to prevent spreading the disease to the uninfected. A plague doctor had to serve a long quarantine after seeing a plague patient. The doctor was regarded as a "contact" who by agreement had to live in isolation to be quarantined.


title: Plague doctor

text: The bargaining which always preceded the final contract often consisted of serious negotiations. For example, the town administrators of Turin in 1630 were considering the terms of an agreement requested by one Dr. Maletto to become their plague doctor. After much negotiating, they instructed their broker representatives to make a fair and prompt deal as soon as possible with this Dr. Maletto. They were told to get the best possible deal for their city, but to be careful not to lose the opportunity of hiring this plague doctor, as it would be difficult to find someone else to perform these dangerous duties at such a low rate.


title: Plague doctor

text: As an example of the tough negotiating that went on between plague doctors and infected European towns, there is in Pavia an original agreement between one Giovanni de Ventura and the city in their archives that shows a sixteen clause contract that was further amended after it was originally written. Clause one originally showed 30 florins per month for pay but was later modified to be net of living expenses. Clause two was originally that the pay was to be given two months in advance but later modified to monthly. Clause five provided originally a severance pay of two months but later modified that to one month's pay. Clause six said "the said master Giovanni shall not be bound nor held under obligation except only in attending the plague patients" which was later amplified with "...the doctor must treat all patients and visit infected places as it shall be found to be necessary." Clause seven had to do with full citizenship and the original text was modified with "according to how he shall behave himself."


title: Plague doctor

text: Bernardino di Francesco Rinaldi obtained a clause in his contract when he was hired as plague doctor by the city of Volterra in 1527 that said essentially that the city had the obligation to provide Bernardino with all and everything necessary for his life support (i.e. food, water), and for these living expenses to be paid through the city expenditures.


title: Plague doctor

text: In 1527, in the city of Prato, a plague doctor named Stefano Mezzettino was seen attending to other patients without a custodian. The rule in the plague doctor contract was that a custodian must always be with the plague doctor when he visits other patients. This created much danger for the public. He was fined for his illegal act and breaking the rule of the plague doctor contract.


title: Microwave oven

text: A microwave oven (commonly referred to as a microwave) is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. This induces polar molecules in the food to rotate and produce thermal energy in a process known as dielectric heating. Microwave ovens heat foods quickly and efficiently because excitation is fairly uniform in the outer of a homogeneous, high-water-content food item.


title: Microwave oven

text: The development of the cavity magnetron in the UK made possible the production of electromagnetic waves of a small enough wavelength (microwaves). American engineer Percy Spencer is generally credited with inventing the modern microwave oven after World War II from radar technology developed during the war. Named the "Radarange", it was first sold in 1946.


title: Microwave oven

text: Raytheon later licensed its patents for a home-use microwave oven that was introduced by Tappan in 1955, but it was still too large and expensive for general home use. Sharp Corporation introduced the first microwave oven with a turntable between 1964 and 1966. The countertop microwave oven was introduced in 1967 by the Amana Corporation. After microwave ovens became affordable for residential use in the late 1970s, their use spread into commercial and residential kitchens around the world, and prices fell rapidly during the 1980s. In addition to cooking food, microwave ovens are used for heating in many industrial processes.


title: Microwave oven

text: Microwave ovens are a common kitchen appliance and are popular for reheating previously cooked foods and cooking a variety of foods. They rapidly heat foods which can easily burn or turn lumpy if cooked in conventional pans, such as hot butter, fats, chocolate or porridge. Microwave ovens usually do not directly brown or caramelize food, since they rarely attain the necessary temperature to produce Maillard reactions. Exceptions occur in cases where the oven is used to heat frying-oil and other oily items (such as bacon), which attain far higher temperatures than that of boiling water.


title: Microwave oven

text: Microwave ovens have a limited role in professional cooking, because the boiling-range temperatures of a microwave oven does not produce the flavorful chemical reactions that frying, browning, or baking at a higher temperature produces. However, such high heat sources can be added to microwave ovens in the form of a convection microwave oven.


title: Microwave oven

text: The exploitation of high-frequency radio waves for heating substances was made possible by the development of vacuum tube radio transmitters around 1920. By 1930 the application of short waves to heat human tissue had developed into the medical therapy of diathermy. At the 1933 Chicago World's Fair, Westinghouse demonstrated the cooking of foods between two metal plates attached to a 10 kW, 60 MHz shortwave transmitter. The Westinghouse team, led by I. F. Mouromtseff, found that foods like steaks and potatoes could be cooked in minutes.


title: Microwave oven

text: However, lower-frequency dielectric heating, as described in the aforementioned patent, is (like induction heating) an electromagnetic heating effect, the result of the so-called near-field effects that exist in an electromagnetic cavity that is small compared with the wavelength of the electromagnetic field. This patent proposed radio frequency heating, at 10 to 20 megahertz (wavelength 30 to 15 meters, respectively). Heating from microwaves that have a wavelength that is small relative to the cavity (as in a modern microwave oven) is due to "far-field" effects that are due to classical electromagnetic radiation that describes freely propagating light and microwaves suitably far from their source. Nevertheless, the primary heating effect of all types of electromagnetic fields at both radio and microwave frequencies occurs via the dielectric heating effect, as polarized molecules are affected by a rapidly alternating electric field.


title: Microwave oven

text: The invention of the cavity magnetron made possible the production of electromagnetic waves of a small enough wavelength (microwaves). The magnetron was a crucial component in the development of short wavelength radar during World War II. In 1937–1940, a multi-cavity magnetron was built by British physicist Sir John Turton Randall, FRSE and coworkers, for the British and American military radar installations in World War II. A higher-powered microwave generator that worked at shorter wavelengths was needed, and in 1940, at the University of Birmingham in England, Randall and Harry Boot produced a working prototype. They invented a valve that could produce pulses of microwave radio energy at a wavelength of 10 cm, an unprecedented discovery.


title: Microwave oven

text: Sir Henry Tizard traveled to the U.S. in late September 1940 to offer the magnetron in exchange for their financial and industrial help (see Tizard Mission). An early 6 kW version, built in England by the General Electric Company Research Laboratories, Wembley, London, was given to the U.S. government in September 1940. The magnetron was later described by American historian James Phinney Baxter III as "[t]he most valuable cargo ever brought to our shores". Contracts were awarded to Raytheon and other companies for the mass production of the magnetron.


title: Microwave oven

text: In 1945, the heating effect of a high-power microwave beam was accidentally discovered by Percy Spencer, an American self-taught engineer from Howland, Maine. Employed by Raytheon at the time, he noticed that microwaves from an active radar set he was working on started to melt a Mr. Goodbar candy bar he had in his pocket. The first food deliberately cooked with Spencer's microwave oven was popcorn, and the second was an egg, which exploded in the face of one of the experimenters.


title: Microwave oven

text: To verify his finding, Spencer created a high-density electromagnetic field by feeding microwave power from a magnetron into a metal box from which it had no way to escape. When food was placed in the box with the microwave energy, the temperature of the food rose rapidly. On 8 October 1945, Raytheon filed a United States patent application for Spencer's microwave cooking process, and an oven that heated food using microwave energy from a magnetron was soon placed in a Boston restaurant for testing.


title: Microwave oven

text: Another early discovery of microwave oven technology was by British scientists, including James Lovelock, who in the 1950s used it to reanimate cryogenically frozen hamsters.


title: Microwave oven

text: In 1947, Raytheon built the "Radarange", the first commercially available microwave oven. It was almost tall, weighed and cost about US$5,000 ($ in dollars) each. It consumed 3 kilowatts, about three times as much as today's microwave ovens, and was water-cooled. The name was the winning entry in an employee contest. An early Radarange was installed (and remains) in the galley of the nuclear-powered passenger/cargo ship NS "Savannah". An early commercial model introduced in 1954 consumed 1.6 kilowatts and sold for US$2,000 to US$3,000 ($ to $ in dollars). Raytheon licensed its technology to the Tappan Stove company of Mansfield, Ohio in 1952. Under contract to Whirlpool, Westinghouse, and other major appliance manufacturers looking to add matching microwave ovens to their conventional oven line, Tappan produced several variations of their built-in model from roughly 1955 to 1960. Due to maintenance (some units were water-cooled), in-built requirement, and cost—US$1,295 ($ in dollars)—sales were limited.


title: Microwave oven

text: Japan's Sharp Corporation began manufacturing microwave ovens in 1961. Between 1964 and 1966, Sharp introduced the first microwave oven with a turntable, an alternative means to promote more even heating of food. In 1965, Raytheon, looking to expand their Radarange technology into the home market, acquired Amana to provide more manufacturing capability. In 1967, they introduced the first popular home model, the countertop Radarange, at a price of US$495 ($ in dollars). Unlike the Sharp models, a motor driven mode stirrer in the top of the oven cavity rotated allowing the food to remain stationary.


title: Microwave oven

text: In the 1960s, Litton bought Studebaker's Franklin Manufacturing assets, which had been manufacturing magnetrons and building and selling microwave ovens similar to the Radarange. Litton developed a new configuration of the microwave oven: the short, wide shape that is now common. The magnetron feed was also unique. This resulted in an oven that could survive a no-load condition: an empty microwave oven where there is nothing to absorb the microwaves. The new oven was shown at a trade show in Chicago, and helped begin a rapid growth of the market for home microwave ovens. Sales volume of 40,000 units for the U.S. industry in 1970 grew to one million by 1975. Market penetration was even faster in Japan, due to a less expensive re-engineered magnetron.


title: Microwave oven

text: Several other companies joined in the market, and for a time most systems were built by defence contractors, who were most familiar with the magnetron. Litton was particularly well known in the restaurant business.


title: Microwave oven

text: While uncommon today, combination microwave-ranges were offered by major appliance manufacturers through much of the 1970's as a natural progression of the technology. Both Tappan and General Electric offered units that appeared to be conventional stove top/oven ranges, but included microwave capability in the conventional oven cavity. Such ranges were attractive to consumers since both microwave energy and conventional heating elements could be used simultaneously to speed cooking, and there was no loss of countertop space. The proposition was also attractive to manufacturers as the additional component cost could better be absorbed compared with countertop units where pricing was increasingly market-sensitive.


title: Microwave oven

text: By 1972, Litton (Litton Atherton Division, Minneapolis) introduced two new microwave ovens, priced at $349 and $399, to tap into the market estimated at $750 million by 1976, according to Robert I Bruder, president of the division. While prices remained high, new features continued to be added to home models. Amana introduced automatic defrost in 1974 on their RR-4D model, and was the first to offer a microprocessor controlled digital control panel in 1975 with their RR-6 model.


title: Microwave oven

text: Formerly found only in large industrial applications, microwave ovens increasingly became a standard fixture of residential kitchens in developed countries. By 1986, roughly 25% of households in the U.S. owned a microwave oven, up from only about 1% in 1971; the U.S. Bureau of Labor Statistics reported that over 90% of American households owned a microwave oven in 1997. In Australia, a 2008 market research study found that 95% of kitchens contained a microwave oven and that 83% of them were used daily. In Canada, fewer than 5% of households had a microwave oven in 1979, but more than 88% of households owned one by 1998. In France, 40% of households owned a microwave oven in 1994, but that number had increased to 65% by 2004.


title: Microwave oven

text: Adoption has been slower in less-developed countries, as households with disposable income concentrate on more important household appliances like refrigerators and ovens. In India, for example, only about 5% of households owned a microwave oven in 2013, well behind refrigerators at 31% ownership. However, microwave ovens are gaining popularity. In Russia, for example, the number of households with a microwave oven grew from almost 24% in 2002 to almost 40% in 2008. Almost twice as many households in South Africa owned microwave ovens in 2008 (38.7%) as in 2002 (19.8%). Microwave oven ownership in Vietnam in 2008 was at 16% of households, versus 30% ownership of refrigerators; this rate was up significantly from 6.7% microwave oven ownership in 2002, with 14% ownership for refrigerators that year.


title: Microwave oven

text: Consumer household microwave ovens usually come with a cooking power of between 600 and 1200 watts. The size of household microwave ovens can vary, but usually have an internal volume of around , and external dimensions of approximately wide, deep and tall.


title: Microwave oven

text: Microwaves can be turntable or flatbed. Turntable ovens include a glass plate or tray. Flatbed ones do not include a plate, so they have a flat and wider cavity.


title: Microwave oven

text: By position and type, US DOE classifies them as (1) countertop or (2) over the range and built-in (wall oven for a cabinet or a drawer model).


title: Microwave oven

text: Traditional microwaves rely on internal high voltage power from a line/mains transformer, but many newer models are powered by an inverter. Inverter microwaves can be useful for achieving more even cooking results, as they offer a seamless stream of cooking power.


title: Microwave oven

text: A traditional microwave only has two power output levels, fully on and fully off. Intermediate heat settings are achieved using duty-cycle modulation and switch between full power and off every few seconds, with more time on for higher settings.


title: Microwave oven

text: An inverter type, however, can sustain lower temperatures for a lengthy duration without having to switch itself off and on repeatedly. Apart from offering superior cooking ability, these microwaves are generally more energy-efficient.


title: Microwave oven

text: , the majority of countertop microwave ovens (regardless of brand) sold in the United States were manufactured by the Midea Group.


title: Microwave oven

text: A microwave oven heats food by passing microwave radiation through it. Microwaves are a form of non-ionizing electromagnetic radiation with a frequency in the so-called microwave region (300MHz to 300GHz). Microwave ovens use frequencies in one of the ISM (industrial, scientific, medical) bands, which are otherwise used for communication amongst devices that do not need a license to operate, so they do not interfere with other vital radio services.


title: Microwave oven

text: Consumer ovens work around a nominal 2.45 gigahertz (GHz)—a wavelength of in the 2.4 GHz to 2.5 GHz ISM band—while large industrial/commercial ovens often use 915 megahertz (MHz)—. Water, fat, and other substances in the food absorb energy from the microwaves in a process called dielectric heating. Many molecules (such as those of water) are electric dipoles, meaning that they have a partial positive charge at one end and a partial negative charge at the other, and therefore rotate as they try to align themselves with the alternating electric field of the microwaves. Rotating molecules hit other molecules and put them into motion, thus dispersing energy.


title: Microwave oven

text: This energy, dispersed as molecular rotations, vibrations and/or translations in solids and liquids, raises the temperature of the food, in a process similar to heat transfer by contact with a hotter body. It is a common misconception that microwave ovens heat food by operating at a special resonance of water molecules in the food. As noted microwave ovens can operate at many frequencies.


title: Microwave oven

text: Microwave heating is more efficient on liquid water than on frozen water, where the movement of molecules is more restricted. Defrosting is done at a low power setting, allowing time for conduction to carry heat to still frozen parts of food. Dielectric heating of liquid water is also temperature-dependent: At 0 °C, dielectric loss is greatest at a field frequency of about 10 GHz, and for higher water temperatures at higher field frequencies. A higher wattage power of the microwave oven results in faster cooking times.


title: Microwave oven

text: Microwave heating is less efficient on fats and sugars than on water because they have a smaller molecular dipole moment. Sugars and triglycerides (fats and oils) absorb microwaves due to the dipole moments of their hydroxyl groups or ester groups. However, due to the lower specific heat capacity of fats and oils and their higher vaporization temperature, they often attain much higher temperatures inside microwave ovens. This can induce temperatures in oil or fatty foods like bacon far above the boiling point of water, and high enough to induce some browning reactions, much in the manner of conventional broiling (UK: grilling), braising, or deep fat frying. The higher heat generated means that microwaving foods high in sugar, starch, or fat may damage some plastic containers. Foods high in water content and with little oil rarely exceed the boiling temperature of water and do not damage plastic.


title: Microwave oven

text: Cookware must be transparent to microwaves. Conductive cookware, such as metal pots, reflects microwaves, and prevents the microwaves from reaching the food. Cookware made of materials with high electrical permittivity will absorb microwaves, resulting in the cookware heating, rather than the food. Cookware made of melamine resin is a common type of cookware that will heat in a microwave oven, reducing the effectiveness of the microwave oven and creating a hazard from burns or shattered cookware.


title: Microwave oven

text: Microwave heating can cause localized thermal runaways in some materials with low thermal conductivity which also have dielectric constants that increase with temperature. An example is glass, which can exhibit thermal runaway in a microwave oven to the point of melting if preheated. Additionally, microwaves can melt certain types of rocks, producing small quantities of molten rock. Some ceramics can also be melted, and may even become clear upon cooling. Thermal runaway is more typical of electrically conductive liquids such as salty water.


title: Microwave oven

text: Another misconception is that microwave ovens cook food "from the inside out", meaning from the center of the entire mass of food outwards. This idea arises from heating behavior seen if an absorbent layer of water lies beneath a less absorbent drier layer at the surface of a food; in this case, the deposition of heat energy inside a food can exceed that on its surface. This can also occur if the inner layer has a lower heat capacity than the outer layer causing it to reach a higher temperature, or even if the inner layer is more thermally conductive than the outer layer making it feel hotter despite having a lower temperature. In most cases, however, with uniformly structured or reasonably homogenous food item, microwaves are absorbed in the outer layers of the item at a similar level to that of the inner layers.


title: Microwave oven

text: Depending on water content, the depth of initial heat deposition may be several centimetres or more with microwave ovens, in contrast with broiling/grilling (infrared) or convection heating—methods which deposit heat thinly at the food surface. Penetration depth of microwaves is dependent on food composition and the frequency, with lower microwave frequencies (longer wavelengths) penetrating further.


title: Microwave oven

text: In use, microwave ovens can be as low as 50% efficient at converting electricity into microwaves, but energy efficient models can exceed 64% efficiency. Stovetop cooking is about 40% efficient. Because they are used fairly infrequently, the average residential microwave oven consumes only 72 kWh per year. Globally, microwave ovens used an estimated 77 TWh per year in 2018, or 0.3% of global electricity generation.


title: Microwave oven

text: A 2000 study by Lawrence Berkeley National Laboratory found that the average microwave drew almost 3 watts of standby power when not being used, which would total approximately 26 kWh per year. New efficiency standards imposed by the United States Department of Energy in 2016 require less than 1 watt, or approximately 9 kWh per year, of standby power for most types of microwave ovens.


title: Microwave oven

text: In most ovens, the magnetron is driven by a linear transformer which can only feasibly be switched completely on or off. (One variant of the GE Spacemaker had two taps on the transformer primary, for high and low power modes.) Usually choice of power level doesn't affect intensity of the microwave radiation; instead, the magnetron is cycled on and off every few seconds, thus altering the large scale duty cycle. Newer models use "inverter" power supplies that use pulse-width modulation to provide effectively continuous heating at reduced power settings, so that foods are heated more evenly at a given power level and can be heated more quickly without being damaged by uneven heating.


title: Microwave oven

text: The microwave frequencies used in microwave ovens are chosen based on regulatory and cost constraints. The first is that they should be in one of the industrial, scientific, and medical (ISM) frequency bands set aside for unlicensed purposes. For household purposes, 2.45 GHz has the advantage over 915 MHz in that 915 MHz is only an ISM band in some countries (ITU Region 2) while 2.45 GHz is available worldwide. Three additional ISM bands exist in the microwave frequencies, but are not used for microwave cooking. Two of them are centered on 5.8 GHz and 24.125 GHz, but are not used for microwave cooking because of the very high cost of power generation at these frequencies. The third, centered on 433.92 MHz, is a narrow band that would require expensive equipment to generate sufficient power without creating interference outside the band, and is only available in some countries.


title: Microwave oven

text: The cooking chamber is similar to a Faraday cage to prevent the waves from coming out of the oven. Even though there is no continuous metal-to-metal contact around the rim of the door, choke connections on the door edges act like metal-to-metal contact, at the frequency of the microwaves, to prevent leakage. The oven door usually has a window for easy viewing, with a layer of conductive mesh some distance from the outer panel to maintain the shielding. Because the size of the perforations in the mesh is much less than the microwaves' wavelength (12.2 cm for the usual 2.45 GHz), microwave radiation cannot pass through the door, while visible light (with its much shorter wavelength) can.


title: Microwave oven

text: Modern microwave ovens use either an analog dial-type timer or a digital control panel for operation. Control panels feature an LED, liquid crystal or vacuum fluorescent display, numeric buttons for entering the cook time, a power level selection feature and other possible functions such as a defrost setting and pre-programmed settings for different food types, such as meat, fish, poultry, vegetables, frozen vegetables, frozen dinners, and popcorn. In the 90s brands such as Panasonic and GE began offering models with a scrolling-text display showing cooking instructions.


title: Microwave oven

text: Power settings are commonly implemented, not by actually varying the effect, but by repeatedly turning the power off and on. The highest setting thus represents continuous power. Defrost might represent power for two seconds followed by no power for five seconds. To indicate cooking has completed, an audible warning such as a bell or a beeper is usually present, and/or "End" usually appears on the display of a digital microwave.


title: Microwave oven

text: Microwave control panels are often considered awkward to use and are frequently employed as examples for user interface design.


title: Microwave oven

text: A variant of the conventional microwave oven is the convection microwave oven. A convection microwave oven is a combination of a standard microwave oven and a convection oven. It allows food to be cooked quickly, yet come out browned or crisped, as from a convection oven. Convection microwave ovens are more expensive than conventional microwave ovens. Some convection microwave ovens—those with exposed heating elements—can produce smoke and burning odors as food spatter from earlier microwave-only use is burned off the heating elements. Some ovens use high speed air; these are known as impingement ovens and are designed to cook food quickly in restaurants, but cost more and consume more power.


title: Microwave oven

text: In 2000, some manufacturers began offering high power quartz halogen bulbs to their convection microwave oven models, marketing them under names such as "Speedcook", "Advantium", "Lightwave" and "Optimawave" to emphasize their ability to cook food rapidly and with good browning. The bulbs heat the food's surface with infrared (IR) radiation, browning surfaces as in a conventional oven. The food browns while also being heated by the microwave radiation and heated through conduction through contact with heated air. The IR energy which is delivered to the outer surface of food by the lamps is sufficient to initiate browning caramelization in foods primarily made up of carbohydrates and Maillard reactions in foods primarily made up of protein. These reactions in food produce a texture and taste similar to that typically expected of conventional oven cooking rather than the bland boiled and steamed taste that microwave-only cooking tends to create.


title: Microwave oven

text: In order to aid browning, sometimes an accessory browning tray is used, usually composed of glass or porcelain. It makes food crisp by oxidizing the top layer until it turns brown. Ordinary plastic cookware is unsuitable for this purpose because it could melt.


title: Microwave oven

text: Frozen dinners, pies, and microwave popcorn bags often contain a susceptor made from thin aluminium film in the packaging or included on a small paper tray. The metal film absorbs microwave energy efficiently and consequently becomes extremely hot and radiates in the infrared, concentrating the heating of oil for popcorn or even browning surfaces of frozen foods. Heating packages or trays containing susceptors are designed for a single use and are then discarded as waste.


title: Microwave oven

text: Microwave ovens produce heat directly within the food, but despite the common misconception that microwaved food cooks from the inside out, 2.45 GHz microwaves can only penetrate approximately into most foods. The inside portions of thicker foods are mainly heated by heat conducted from the outer .


title: Microwave oven

text: Uneven heating in microwaved food can be partly due to the uneven distribution of microwave energy inside the oven, and partly due to the different rates of energy absorption in different parts of the food. The first problem is reduced by a stirrer, a type of fan that reflects microwave energy to different parts of the oven as it rotates, or by a turntable or carousel that turns the food; turntables, however, may still leave spots, such as the center of the oven, which receive uneven energy distribution. The location of dead spots and hot spots in a microwave oven can be mapped out by placing a damp piece of thermal paper in the oven.


title: Microwave oven

text: When the water-saturated paper is subjected to the microwave radiation it becomes hot enough to cause the dye to be darkened which can provide a visual representation of the microwaves. If multiple layers of paper are constructed in the oven with a sufficient distance between them a three-dimensional map can be created. Many store receipts are printed on thermal paper which allows this to be easily done at home.


title: Microwave oven

text: The second problem is due to food composition and geometry, and must be addressed by the cook, by arranging the food so that it absorbs energy evenly, and periodically testing and shielding any parts of the food that overheat. In some materials with low thermal conductivity, where dielectric constant increases with temperature, microwave heating can cause localized thermal runaway. Under certain conditions, glass can exhibit thermal runaway in a microwave oven to the point of melting.


title: Microwave oven

text: Due to this phenomenon, microwave ovens set at too-high power levels may even start to cook the edges of frozen food while the inside of the food remains frozen. Another case of uneven heating can be observed in baked goods containing berries. In these items, the berries absorb more energy than the drier surrounding bread and cannot dissipate the heat due to the low thermal conductivity of the bread. Often this results in overheating the berries relative to the rest of the food. "Defrost" oven settings either use low power levels or turn the power off and on repeatedly - designed to allow time for heat to be conducted within frozen foods from areas that absorb heat more readily to those which heat more slowly. In turntable-equipped ovens, more even heating can take place by placing food off-center on the turntable tray instead of exactly in the center, as this results in more even heating of the food throughout.


title: Microwave oven

text: There are microwave ovens on the market that allow full-power defrosting. They do this by exploiting the properties of the electromagnetic radiation LSM modes. LSM full-power defrosting may actually achieve more even results than slow defrosting.


title: Microwave oven

text: Microwave heating can be deliberately uneven by design. Some microwavable packages (notably pies) may include materials that contain ceramic or aluminium flakes, which are designed to absorb microwaves and heat up, which aids in baking or crust preparation by depositing more energy shallowly in these areas. Such ceramic patches affixed to cardboard are positioned next to the food, and are typically smokey blue or gray in colour, usually making them easily identifiable; the cardboard sleeves included with Hot Pockets, which have a silver surface on the inside, are a good example of such packaging. Microwavable cardboard packaging may also contain overhead ceramic patches which function in the same way. The technical term for such a microwave-absorbing patch is a susceptor.


title: Microwave oven

text: Any form of cooking diminishes overall nutrient content in food, particularly water-soluble vitamins common in vegetables, but the key variables are how much water is used in the cooking, how long the food is cooked, and at what temperature. Nutrients are primarily lost by leaching into cooking water, which tends to make microwave cooking effective, given the shorter cooking times it requires and that the water heated is in the food. Like other heating methods, microwaving converts vitamin B from an active to inactive form; the amount of conversion depends on the temperature reached, as well as the cooking time. Boiled food reaches a maximum of (the boiling point of water), whereas microwaved food can get internally hotter than this, leading to faster breakdown of vitamin B. The higher rate of loss is partially offset by the shorter cooking times required.


title: Microwave oven

text: Spinach retains nearly all its folate when cooked in a microwave oven; when boiled, it loses about 77%, leaching nutrients into the cooking water. Bacon cooked by microwave oven has significantly lower levels of nitrosamines than conventionally cooked bacon. Steamed vegetables tend to maintain more nutrients when microwaved than when cooked on a stovetop. Microwave blanching is 3–4 times more effective than boiled-water blanching for retaining of the water-soluble vitamins, folate, thiamin and riboflavin, with the exception of vitamin C, of which 29% is lost (compared with a 16% loss with boiled-water blanching).


title: Microwave oven

text: Microwave ovens heat food without getting hot themselves. Taking a pot off a stove, unless it is an induction cooktop, leaves a potentially dangerous heating element or trivet that remains hot for some time. Likewise, when taking a casserole out of a conventional oven, one's arms are exposed to the very hot walls of the oven. A microwave oven does not pose this problem.


title: Microwave oven

text: Food and cookware taken out of a microwave oven are rarely much hotter than . Cookware used in a microwave oven is often much cooler than the food because the cookware is transparent to microwaves; the microwaves heat the food directly and the cookware is indirectly heated by the food. Food and cookware from a conventional oven, on the other hand, are the same temperature as the rest of the oven; a typical cooking temperature is . That means that conventional stoves and ovens can cause more serious burns.


title: Microwave oven

text: The lower temperature of cooking (the boiling point of water) is a significant safety benefit compared with baking in the oven or frying, because it eliminates the formation of tars and char, which are carcinogenic. Microwave radiation also penetrates deeper than direct heat, so that the food is heated by its own internal water content. In contrast, direct heat can burn the surface while the inside is still cold. Pre-heating the food in a microwave oven before putting it into the grill or pan reduces the time needed to heat up the food and reduces the formation of carcinogenic char. Unlike frying and baking, microwaving does not produce acrylamide in potatoes, however unlike deep-frying, it is of only limited effectiveness in reducing glycoalkaloid (i.e., solanine) levels. Acrylamide has been found in other microwaved products like popcorn.


title: Microwave oven

text: Studies have investigated the use of the microwave oven to clean non-metallic domestic sponges which have been thoroughly wetted. A 2006 study found that microwaving wet sponges for two minutes (at 1000 watt power) removed 99% of coliforms, "E. coli" and MS2 phages. "Bacillus cereus" spores were killed at four minutes of microwaving.


title: Microwave oven

text: A 2017 study was less affirmative: about 60% of the germs were killed but the remaining ones quickly re-colonized the sponge.


title: Microwave oven

text: Water and other homogeneous liquids can superheat when heated in a microwave oven in a container with a smooth surface. That is, the liquid reaches a temperature slightly above its normal boiling point without bubbles of vapour forming inside the liquid. The boiling process can start explosively when the liquid is disturbed, such as when the user takes hold of the container to remove it from the oven or while adding solid ingredients such as powdered creamer or sugar. This can result in spontaneous boiling (nucleation) which may be violent enough to eject the boiling liquid from the container and cause severe scalding.