QUES: The differential analyser, a mechanical analog computer designed to solve differential equations by integration, used wheel-and-disc mechanisms to perform the integration. In 1876 Lord Kelvin had already discussed the possible construction of such calculators, but he had been stymied by the limited output torque of the ball-and-disk integrators. In a differential analyzer, the output of one integrator drove the input of the next integrator, or a graphing output. The torque amplifier was the advance that allowed these machines to work. Starting in the 1920s, Vannevar Bush and others developed mechanical differential analyzers.
During what decade were mechanical differential analyzers developed?

ANS: 1920s

QUES: Over time, the relative power of these five nations fluctuated, which by the dawn of the 20th century had served to create an entirely different balance of power. Some, such as the United Kingdom and Prussia (as the founder of the newly formed German state), experienced continued economic growth and political power. Others, such as Russia and Austria-Hungary, stagnated. At the same time, other states were emerging and expanding in power, largely through the process of industrialization. These countries seeking to attain great power status were: Italy after the Risorgimento, Japan after the Meiji Restoration, and the United States after its civil war. By the dawn of the 20th century, the balance of world power had changed substantially since the Congress of Vienna. The Eight-Nation Alliance was a belligerent alliance of eight nations against the Boxer Rebellion in China. It formed in 1900 and consisted of the five Congress powers plus Italy, Japan, and the United States, representing the great powers at the beginning of 20th century.
What countries found their economic growth in early 20th century?

ANS: United Kingdom and Prussia

QUES: The Rev. John J. Cavanaugh, C.S.C. served as president from 1946 to 1952. Cavanaugh's legacy at Notre Dame in the post-war years was devoted to raising academic standards and reshaping the university administration to suit it to an enlarged educational mission and an expanded student body and stressing advanced studies and research at a time when Notre Dame quadrupled in student census, undergraduate enrollment increased by more than half, and graduate student enrollment grew fivefold. Cavanaugh also established the Lobund Institute for Animal Studies and Notre Dame's Medieval Institute. Cavanaugh also presided over the construction of the Nieuwland Science Hall, Fisher Hall, and the Morris Inn, as well as the Hall of Liberal Arts (now O'Shaughnessy Hall), made possible by a donation from I.A. O'Shaughnessy, at the time the largest ever made to an American Catholic university. Cavanaugh also established a system of advisory councils at the university, which continue today and are vital to the university's governance and development
Which institute involving animal life did Cavanaugh create at Notre Dame?

ANS: Lobund Institute for Animal Studies

QUES: Instruments like the duduk, the dhol, the zurna and the kanun are commonly found in Armenian folk music. Artists such as Sayat Nova are famous due to their influence in the development of Armenian folk music. One of the oldest types of Armenian music is the Armenian chant which is the most common kind of religious music in Armenia. Many of these chants are ancient in origin, extending to pre-Christian times, while others are relatively modern, including several composed by Saint Mesrop Mashtots, the inventor of the Armenian alphabet. Whilst under Soviet rule, Armenian classical music composer Aram Khatchaturian became internationally well known for his music, for various ballets and the Sabre Dance from his composition for the ballet Gayane.
What instruments are used in Armenian folk music?

ANS:
the duduk, the dhol, the zurna and the kanun