The requirement of Brevity In the course of Contributed Making decisions (SDM) regarding Cancer mali
Author : Castro Bowling | Published On : 25 Oct 2024
The results obtained from preliminary experiments on a composite material (carbon fibers embedded in epoxy resin) and on a high purity copper sample preheated to 323 K and 573 K, respectively, are presented. The performance and robustness of this heating device are potentially valuable for extending the range of studies in dynamic loading experiments for various materials under ramp compression using HPP drivers.Raja Ramanna Centre for Advanced Technology (RRCAT) has an ongoing program to develop 650 MHz, 5-cell elliptical superconducting RF (SCRF) cavities under the Indian Institutes and Fermilab Collaboration. The elliptical multi-cell SCRF cavity fabrication process involves forming of half-cells and their precise machining and joining by electron beam welding to form end groups and dumbbells, which are then joined to make the final cavity. To ensure that the final welded cavity achieves physical lengths and resonant frequencies within design tolerance and has good field flatness, the measurement and correction of resonant frequency are carried out for dumbbells and end groups. A novel method to identify the frequency of individual half-cells in a dumbbell cavity and a dedicated tuning fixture to correct them had been developed. The paper details the RF characterization and correction procedure employed during fabrication of the first six 650 MHz cavities at RRCAT.Electron-temperature (Te) measurements in implosions provide valuable diagnostic information, as Te is unaffected by residual flows and other non-thermal effects unlike ion temperature inferred from a fusion product spectrum. In OMEGA cryogenic implosions, measurement of Te(t) can be used to investigate effects related to time-resolved hot-spot energy balance. The proposed diagnostic utilizes five fast-rise (∼15 ps) scintillator channels with distinct x-ray filtering. Titanium and stepped aluminum filtering were chosen to maximize detector sensitivity in the 10 keV-20 keV range, as it has been shown that these x rays have similar density and temperature weighting to the emitted deuterium-tritium fusion neutrons. Initial data collected using a prototype nosecone on the existing neutron temporal diagnostic demonstrate the validity of this diagnostic technique. The proposed system will be capable of measuring spatially integrated Te(t) with 20 ps time resolution and less then 10% uncertainty at peak emission in cryogenic DT implosions.To use acoustic-emission technology to detect leaks inside valves, the necessary first step is to model the valve-internal-leakage acoustic-emission signal (VILAES) mathematically. read more A multi-variable classification model that relates the VILAES characteristics and the leakage rate under varying pressure is built by combining time-frequency domain characteristics and the random-forest method. A Butterworth bandpass filter is used to preprocess the VILAES from a liquid medium, and the best frequency band for filtering is determined as being 140 kHz-180 kHz. Then, (i) the standard deviation, (ii) root mean square, (iii) wavelet packet entropy, (iv) peak standard-deviation probability density, and (v) spectrum area are calculated as the VILAES characteristics, and six parameters-the pressure and the five VILAES characteristics-are used as the inputs for the random-forest classification model. Analysis shows that the five VILAES characteristics increase with an increase in the leakage rate. The multi-variable classification model is established by random forest to determine whether the valve leakage is small, medium, or large. The random forest uses many decision trees to predict the final result. For the same experimental data, the accuracy and operating time of the multi-variable classification model are compared with those of a support-vector-machine classification method for the bandpass and wavelet packet filtering preprocessing methods. The results show that the modeling method based on the combination of time-frequency characteristics and random forest has shorter operating time and higher accuracy.This study proposes a temperature model for the relaxation of magnetic nanoparticles and a phase measurement method under a mixing-frequency excitation field, which can improve the accuracy of temperature measurements in magnetic nanothermometry. According to the Debye-based magnetization model for magnetic nanoparticles, phases at mixing frequencies are used to solve the problem of a delay in the relaxation phase of the magnetic field at a high frequency. This method can improve the signal-to-noise ratio of the response of the magnetic nanoparticles and weaken the phase shift of the detection coils caused by the changes in temperature. The results of experiments show that the proposed method can achieve static temperature measurement error less than 0.1 K and dynamic temperature measurement error less than 0.2 K.To survey deep-buried and non-metallic pipelines without excavation, a pipeline survey instrument composed of a data collection and data processing part is developed. The data collection part is composed of a walking machine, a nine-axis micro-electro-mechanical system inertial measurement unit (MEMS-IMU) installed on the walking machine, odometers based on Hall magnetic switches, and a control/data storage circuit, while data processing is executed on the personal computer, where the attitude and trajectory are acquired with the complementary filter and dead reckoning on the collected data. Key technologies include the following (1) the gyro-bias is estimated with the parking mode when there is no angular motion excitation; (2) a magnetometer is introduced to assist MEMS-IMU tracking azimuth changes; (3) calibration based on ellipsoid fitting is designed for magnetometers and accelerometers without any references; (4) stretching and rotation on calculated trajectory are executed with position information of both pipeline ends. Test results on a pipeline of 104 m constructed on the ground show that the maximum error on the lateral direction is 0.13 m and the height is 0.06 m, while the mean errors are -0.04 m and -0.001 m, respectively.