Balthasar van der Pol

Balthasar van der Pol was born on 27 January 1889 in Utrecht, Netherlands, the son of Balthazar van der Pol and Gerhardina Clasina Steffens. From 1911 to 1916, he studied physics at Utrecht University. After graduation, he travelled to England, where he worked under Ambrose Fleming at University College London and J. J. Thomson at the University of Cambridge. While in England, he studied the heuristics of wireless reception onboard ships. On 2 June 1917 in London, van der Pol married Pietronetta Posthuma, with whom he had a son and two daughters. In 1919, upon his return to the Netherlands, van der Pol became an assistant to Hendrik Lorentz at Teylers Museum in Harlem and returned to Utrecht University. The following year, he received his Ph.D. under Willem Henri Julius at Utrecht. In 1922, van der Pol joined Philips Research Laboratories in Eindhoven, where he worked until his retirement in 1949. In addition, he was appointed Professor of Theoretical Electricity at Technische Hogeschool Delft (now Delft University of Technology) in 1938. Van der Pol died on 6 October 1959 in Wassenaar at the age of 70. == Research ==

As observed by Hendrik Casimir, "Radio might have remained a field of haphazard empiricism along with wild commercial ventures, but for the influence of men like Van der Pol who stressed the need for a more scientific approach." The differential equations of coupled electrical systems drew his interest, and he developed the idea of "relaxation oscillations". With J. van der Mark he applied the idea to the heartbeat, which provided one of the earliest quantitative models of the action potential. These studies led him to the van der Pol equation and Oliver Heaviside’s operational calculus for dealing with differential equations. He submitted articles to Philosophical Magazine on the operational calculus and, in coordination with H. Bremmer, wrote Modern Operational Calculus based on the Two-sided Laplace Integral, published by Cambridge University Press. == Awards and honours ==

In 1935, van der Pol was awarded the Medal of Honor by the Institute of Radio Engineers "for his fundamental studies and contributions in the field of circuit theory and electromagnetic wave propagation phenomena". The asteroid 10443 van der Pol is named after him. In 1949, van der Pol became a Member of the Royal Netherlands Academy of Arts and Sciences. == Works ==

• 1928: (with J van der Mark) The Heartbeat considered as a Relaxation oscillation, and an Electrical Model of the Heart. Phil. Mag. Suppl. No. 6 pp 763–775 • 1947: An electro-mechanical investigation of the Riemann zeta function in the critical strip, Bulletin of the American Mathematical Society 53: 976–81 • 1964: (with H. Bremmer) Operational Calculus Cambridge University Press • 1960: Selected Scientific Papers, North-Holland Two volumes == References ==