Peter Alexis Boodberg (born Pyotr Alekseyevich von Budberg; 8 April 1903 – 29 June 1972) was a Russian-American scholar, linguist, and sinologist who taught at the University of California, Berkeley for 40 years.
 Boodberg was influential in 20th century developments in the studies of the development of Chinese characters, Chinese philology, and Chinese historical phonology.
Frichs is a Danish company based in Horsens, founded in 1854 in Aarhus.
 Frichs today produce ship engines but started out in the 19th century producing a long range of farm and industry equipment, ships, church bells, cranes and later through the 20th century locomotives and train carriages.
 In the early to mid 20th century it was a major company and employer in Aarhus at its height employing some 1000 people.
 The company was the sole Danish supplier of locomotives for the Danish State Railways from 1919 to the mid 1950s and sold locomotives across Europe and to Siam and New Zealand.
 In 1980 the company was sold to "Kosan" and then restructured and rebased to Horsens.
Steel guitar is a type of guitar or the method of playing the instrument.
 Developed in Hawaii in the late 19th and early 20th centuries, a steel guitar is usually positioned horizontally; strings are plucked with one hand, while the other hand changes the pitch of one or more strings with the use of a bar or slide called a steel (generally made of metal, but also of glass or other materials).
 The earliest use of an electrified steel guitar was first made in the early 1930s by Bob Dunn of Milton Brown and His Brownies, a western swing band from Fort Worth, Texas; the instrument was perfected in the mid to late 1930s by Fort Worth's Leon McAluff, who played for western swing band Bob Wills and His Texas Playboys.
 Nashville later picked up the use of the steel guitar in the early days of the late 1940s and early 1950s "Honky Tonk" country & western music with a number of fine steel guitarists backing names like :Hank Williams, Lefty Frizell and Webb Pierce.
 The term steel guitar is often mistakenly used to describe any metal body resophonic guitar.
The New York Central Hudsons were a series of 4-6-4 "Hudson" type steam locomotives built by the American Locomotive Company and the Lima Locomotive Works from 1927 to 1938 for the New York Central Railroad.
 Named after the Hudson River, the 4-6-4 wheel arrangement came to be known as the "Hudson" type in the United States as these locomotives were the first examples built and used in North America.
 Built for high-speed passenger train work, the Hudson locomotives were famously known for hauling the New York Central's crack passenger trains, such as the "20th Century Limited" and the "Empire State Express".
 With the onset of diesel locomotives in the mid 20th Century, all Hudson locomotives were retired, with none preserved.
Raphael S. Soriano, FAIA, (August 1, 1904 – July 21, 1988) was an architect and educator, who helped define a period of 20th-century architecture that came to be known as Mid-century modern.
 He pioneered the use of modular prefabricated steel and aluminum structures in residential and commercial design and construction.
Zurvanism is an extinct heretical branch of Zoroastrianism in which the divinity Zurvan is a First Principle (primordial creator deity) who engendered equal-but-opposite twins, Ahura Mazda and Angra Mainyu.
 Zurvanism is also known as "Zurvanite Zoroastrianism", and may be contrasted with Mazdaism, which is the surviving form of Zoroastrianism and in which Ahura Mazda and Angra Mainyu are either themselves primordial (the traditional view), or the 19th/20th century developments in which Ahura Mazda is no longer the Creator of only the good, but also perceived as the origin of Angra Mainyu.
Mid-century modern is a term that describes mid–20th century developments in interior, product, and graphic design, architecture, and urban development from roughly 1933 to 1965.
 The term, employed as a style descriptor as early as the mid-1950s, was reaffirmed in 1983 by Cara Greenberg in the title of her book, "Mid-Century Modern: Furniture of the 1950s" (Random House), celebrating the style that is now recognized by scholars and museums worldwide as a significant design movement.
New materials in 20th-century art were introduced to art making from the very beginning of the century.
 The introduction of new materials (and techniques) and heretofore non-art materials helped drive change in art during the 20th century.
 Traditional materials and techniques were not necessarily displaced in the 20th century.
 Rather they functioned alongside innovations that came with the 20th century.
 Such mainstays as oil-on-canvas painting, and sculpting in traditional materials continued right through the 20th century into the 21st century.
 Furthermore, even "traditional" materials were greatly expanded in the course of the 20th century.
 The number of pigments available to artists (painters, primarily) has increased both in quantity and quality, by most reckoning.
 New formulations for traditional materials especially the commercial availability of acrylic paint have become widely used, introducing initial issues over their stability and longevity.
Smog is a type of air pollutant.
 The word "smog" was coined in the early 20th century as a portmanteau of the words smoke and fog to refer to smoky fog, its opacity, and odour.
 The word was then intended to refer to what was sometimes known as pea soup fog, a familiar and serious problem in London from the 19th century to the mid 20th century.
 This kind of visible air pollution is composed of nitrogen oxides, sulphur oxides, ozone, smoke or particulates among others (less visible pollutants include carbon monoxide, CFCs and radioactive sources).
 Human-made smog is derived from coal emissions, vehicular emissions, industrial emissions, forest and agricultural fires and photochemical reactions of these emissions.
Anarchism in the United States began in the mid 19th century and started to grow in influence as it entered the American labor movements, growing an anarcho-communist current as well as gaining notoriety for violent propaganda by the deed and campaigning for diverse social reforms in the early 20th century.
 As the post-World War II era anarchism regained influence through new developments such as anarcho-pacifism, the American new left and the counterculture of the 1960s.
 In contemporary times, anarchism in the United States influenced and became influenced and renewed by developments both inside and outside the worldwide anarchist movement such as platformism, insurrectionary anarchism, the new social movements (anarcha-feminism, queer anarchism and green anarchism) and the alterglobalization movements.

Question: What type of steel was used in mid–20th century developments and was a Raphael S. Soriano specialty?
Answer: prefabricated steel