An experimental study of the near wake of a two-dimensional hypersonic blunt body with mass addition

An experimental investigation of the steady, laminar near-wake flow field of a two-dimensional, adiabatic, circular cylinder with surface mass transfer has been made at a free-stream Mach number of 6.0. The pressure and mass-concentration fields associated with the transfer of argon, nitrogen or helium into the near wake were studied for mass transfer from the forward stagnation region, and from the base. For sufficiently low mass transfer rates from the base, for which a recirculating zone exists, the entire near-wake flow field correlates with the momentum flux, not the mass flux, of the injectant, and the mass-concentration field is determined by counter-current diffusion into the reversed flow. For mass addition from the forward stagnation region, the pressure field is undisturbed and the mass-concentration field is nearly uniform in the region of reversed flow. The axial decay of argon mass concentration in the intermediate wake, downstream of the neck, is explained with the aid of an integral solution in the incompressible plane, from which the location of the virtual origin for the asymptotic far-wake solution has been derived as one result

Working across species down on the farm: Howard S Liddell and the development of comparative psychopathology, c. 1923 to 1962

Seeking a scientific basis for understanding and treating mental illness, and inspired by the work of Ivan Pavlov, American physiologists, psychiatrists and psychologists in the 1920s turned to nonhuman animals. This paper examines how new constructs such as “experimental neurosis” emerged as tools to enable psychiatric comparison across species. From 1923 to 1962, the Cornell “Behavior Farm” was a leading interdisciplinary research center pioneering novel techniques to experimentally study nonhuman psychopathology. Led by the psychobiologist Howard Liddell, work at the Behavior Farm formed part of an ambitious program to develop new preventative and therapeutic techniques and bring psychiatry into closer relations with physiology and medicine. At the heart of Liddell’s activities were a range of nonhuman animals, including pigs, sheep, goats and dogs, each serving as a proxy for human patients. We examine how Pavlov’s conceptualization of ‘experimental neurosis’ was used by Liddell to facilitate comparison across species and communication between researchers and clinicians. Our close reading of his experimental system demonstrates how unexpected animal behaviors and emotions were transformed into experimental virtues. However, to successfully translate such behaviors from the animal laboratory into the field of human psychopathology, Liddell increasingly reached beyond, and, in effect, redefined, the Pavlovian method to make it compatible and compliant with an ethological approach to the animal laboratory. We show how the resultant Behavior Farm served as a productive “hybrid” place, containing elements of experiment and observation, laboratory and field. It was through the building of close and more naturalistic relationships with animals over extended periods of time, both normal and pathological, and within and outside of the experimental space, that Liddell could understand, manage, and make useful the myriad behavioral complexities that emerged from the life histories of experimental animals, the researchers who worked with them, and their shared relationships to the wider physical and social environments