Physics

  2010 MAR 16 - (VerticalNews.com) -- According to recent research published in the International Journal of Thermophysics, "The use of a typical measuring cryostat with a standard temperature controller was proposed for investigation of the temperature dependence of the thermal diffusivity of transparent samples. The basic idea is to use the cryostat heater to control the mean sample temperature and to generate the thermal wave in it, simultaneously. ...read more

  2010 MAR 16 - (VerticalNews.com) -- "High-resolution ultrasonic spectroscopy was applied for real-time monitoring of the heat-induced denaturation and aggregation processes in aqueous solutions of beta-lactoglobulin. The temperature profiles for the ultrasonic velocity and attenuation in the frequency range from 4MHz to 16MHz were measured during heating and cooling cycles, 35A degrees C to 120A degrees C to 35A degrees C, with different heating and cooling rates," scientists in Dublin, Ireland report ...read more

  2010 MAR 16 - (VerticalNews.com) -- "In this article, results of the measurements of the longitudinal and transverse wave velocities in steel have been presented as a function of temperature. The conducted tests involved two types of corrosion-resistant steel: X14CrMoS17 and X90CrMoV18," scientists writing in the International Journal of Thermophysics report.

  "The tests were based on the ultrasonic wave transition method using transducers operating at 5.4 MHz for the longitudinal wave and 3.2 MHz for the transverse wave. Measurements of the wave velocity were taken at temperatures from 293 K to 1,173 K. The longitudinal wave velocity in X14CrMoS17 steel varies from 6,002 m center dot s(-1) at 293 K to 5,115 m center dot s(-1) at 1,173 K, while the velocity in the X90CrMoV18 steel changes from 5,975 m center dot s(-1) at 293 K to 5,381 m center dot s(-1) at 1,023 K. The transverse wave velocities vary from 3,239 m center dot s(-1) at 293 K to 2,449 m center dot s(-1) at 1,173 K in X14CrMoS17 steel, and from 3,251 m center dot s(-1) at 293 K to 2,478 m center dot s(-1) at 1,173 K in X90CrMoV18 steel. The obtained results represented a basis for determination of the properties of the steels examined, such as Young's modulus, Poisson's ratio, Helmholtz's modulus of volume elasticity, or Lame's constants. The results have been verified by comparing the Young's modulus obtained with the values corresponding to individual steel grades and temperatures (293 K, 373 K, 473 K, 573 K, and 673 K) obtained by traditional methods of measuring mechanical properties as provided in PN-EN 10088-1:2007," wrote K. Nowacki and colleagues, Silesian Technical University ...read more