Use thermophysical property to quantify state of HIFU treatment for VLS

The aim of this study is to evaluate the performance of ADT methods in grading the effectiveness of HIFU treatment for VLS. High-intensity focused ultrasound has been identified as a promising treatment modality for vulvar lichen sclerosus, a common inflammatory disorder associated with an increased risk of developing vulvar carcinoma. With small probe on extensive VLS parts, the therapy was sometimes uneven, thus the total doses of HIFU machine couldn’t indicate the curative effect at each part. The current therapeutic effect was based on symptoms and skin appearance after 3 months, which was time-consuming. Until now, there has been no immediate quantitative assessment method of HIFU therapeutic response for VLS. In our study, active dynamic IR thermal (ADT) was scheduled to undergo HIFU therapy before and after treatment. The thermal time constant was calculated based on ADT images measured both before and after HIFU treatment. In the result of pig phantom measurements, with each part approximately the same thermal time constant before HIFU treatment, the change of thermal time constant was strictly positively associated with HIFU dose onto each part. This study demonstrates the clinical potential of ADT in fast and effective quantify state of HIFU treatment for VLS.

Estimation of Prepressure in Hydraulic Piston Accumulators for Industrial Wind Turbines Using Multi-Model Adaptive Estimation

Failures in pitch systems may cause fatal damage to industrial wind turbines. One of the main reasons for failures in pitch systems is gas leakages of hydraulic accumulators. Due to the limited accessibility of offshore turbines, automated fault detection algorithms potentially increase turbine availability. The gas leakage is detected without downtime by using a model-based approach together with a bank and extended Kalman filters (EKF’s). The residual is analyzed using multi-model adaptive estimation (MMAE). The applied accumulator model relies on a thermal time constant describing the heat flux from the gas to the surroundings. The thermal time constant has been empirically derived from a prepressure of 50 to 172 bar. The fault detection algorithm is tested experimentally in a laboratory on a 25 liters piston accumulator using a load scenario obtained from real turbine data and a prepressure range of 50–140 bar. The Bank of EKF’s can classify the prepressure within a range and thereby detect if a gas leakage has occurred before it results in failure.

Task‐specific measurement uncertainty budget of Curvic‐coupling using analytical methods

A number of Industrial reference components manufactured by grinding to achieve tight dimensional tolerances. In this paper, we present an uncertainty budget of a reference forty-tooth #Curvic measured using an accurate Coordinate Measuring Machine (CMM) in a temperature-controlled laboratory. A number of measurements conducted on Curvicto assess measurement repeatability and reproducibility. Expanded uncertainty budget evaluated from twenty-one Influencing factors, giving8.7 µm (7.1 µm from Type A) and 11 µm (9.6 µm from Type A), respectively, for repeatability and reproducibility test (k >2). Measurement uncertainty due to steady-state thermal effects is 2.2 µm. An adaptable model is presented to evaluate transient thermal effects, a factor often neglected in measurement uncertainty. Thermal time constant uncertainty associated with transient thermal effects is evaluated u(τ)= ±398 s, which corresponds to ±15 % of thermal time constant expanded uncertainty, u(τ)= ±2570 s. #Curvic® (Curvic is a trademark of The Gleason Works, 1000 University Avenue, Rochester, NY, 14603, USA)

Thermal processes during local laser heating of biological tissues

Introduction. Lasers in medicine are currently widely used for both diagnosis and treatment. Studies of the thermal processes that occur when a person is exposed to laser radiation have made it possible to developinnovative methods of treating many diseases. Purpose: to study thermal processes in biological tissues during their local laser heating (mathematical model and experiment). Materials and methods. Using the developed mathematical model of the process of local heating of a certain region inside biological tissue, we studied the process of heating the environment by continuous and pulsed laser radiation using infrared light with a wavelength of 0.98 μm, red light with a wavelength of 0.65 μm, green light with a wavelength 0.5 microns and blue light with a wavelength of 0.435 microns. Results. The sizes of the heated region, the time of establishment and decrease in temperature are determined. The calculation results are in good agreement with the obtained experimental data. Findings. The mode of heating biological tissue with laser radiation depends on the wavelength. The maximum heating temperature of the irradiated section with a radiation pulse duration much shorter than the thermal time constant is independent of the shape and duration of the pulse and is determined only by the energy of the absorbed radiation. The distribution of heat into the medium during the duration of the pulse is determined by its duration and thermal diffusivity of the tissue. To reduce the heating of the surrounding tissue, it is necessary to use short radiation pulses. The progress of tissue heating by a sequence of radiation pulses depends on the relationship between the duration of the pulses, the period of their repetition, and the thermal time constant of the medium. The average (smoothed) temperature is the same as when heated with continuous power equal to the average power of the pulse-modulated radiation.