A NEW HARDNESS TESTING METHOD FOR ELONGATED PRODUCTS

PREDICTIVE CONTROL OF SYSTEMS WITH MULTIPLEXED MEASUREMENTS

For high precision and accuracy in isotopic ratio measurement of transuranic elements using laser ablation assisted resonance ionization mass spectrometry, a dynamic correction method based on correlation of ion signals with energy and timing of each laser pulse was proposed. The feasibility of this dynamic correction method was investigated through the use of a programmable electronics device for fast acquisition of the energy and timing of each laser pulse.

In this paper, we propose five data fusion schemes for the Internet of Things (IoT) scenario,which are Relief and Perceptron (Re-P), Relief and Genetic Algorithm Particle Swarm Optimization (Re-GAPSO), Genetic Algorithm and Artificial Neural Network (GA-ANN), Rough and Perceptron (Ro-P)and Rough and GAPSO (Ro-GAPSO). All the schemes consist of four stages, including preprocessingthe data set based on curve fitting, reducing the data dimension and identifying the most effective featuresets according to data correlation, training classification algorithms, and finally predicting new databased on classification algorithms. The results derived from five compound schemes are investigated andcompared with each other with three metrics, namely, Quality of Train (QoT) Accuracy (Ac) and StorageCapacity (SC). While the Re-P scheme is only capable of separating classes that are linearly separable,Re-GAPSO one is a dynamic method, appropriate for constantly changing problems of the real life. Onthe other hand, GA-ANN is a Wrapper method and despite Relief can adapt itself to the machine learningalgorithm. Meanwhile, Ro-P scheme is useful for analyzing vague and imprecise information and, unlikeGA-ANN, has less calculative costs. Among these five schemes, Ro-GAPSO is a more precise one, whichhas less calculative cost and does not become stuck in local minima. Experimental results show that Re-Poutperforms other proposed and existing methods in terms of computational time complexity.

The metrological problems of measuring the physic and mechanical characteristics of materials by dynamic indentation are considered. It is shown that the estimation of measurement error demanding the creation of the reference blocks is ineffective due to the wide variety of controlled materials and a wide range of changes in their properties. A technique has been developed for evaluating the accuracy of measurements based on the errors of individual parameters included in the calculation equation, i.e. by determining the error of indirect measurements. The technique is based on the estimation of the boundaries of the random error of the measured characteristics of the material and the non-excluded systematic errors of the parameters that are used for the calculations of needed characteristics. The results of experimental studies are presented, indicating that due to the different character of the dependencies of hardness and elastic modulus, the error in measuring the elastic modulus exceeds the error in measuring hardness. In addition, it was found that the error in measuring the characteristics of materials by the dynamic indentation method exceeds the measurement error by the static indentation method and can be reduced by increasing the accuracy of the equipment used for the registration of impact process. The obtained values of the physic and mechanical characteristics of the materials and the values of the measurement error show that the dynamic indentation method can effectively solve the problem of non-destructive testing of hardness, elastic modulus, and strain hardening exponent of metals and products with an appropriate error.

The article is devoted to modification of the impact devices of Leeb hardness testers for the implementation of the dynamic instrumented indentation method. The results obtained made it possible to construct a load–displacement curve using primary EMF signals and made it possible to determine the values of the dissipated and elastic impact body energy, the maximal load of indentation, the maximal and residual penetration depth and the geometric parameters of the indentation region, namely the contact area of the indenter with the surface and the volume of the displaced material. The listed parameters of the indentation process allow us to measure the contact and volume hardness, the elastic modulus and the yield strength of test objects with portable hardness testers.

Purpose of research. Is to develop a layout of an experimental setup that allows conducting research with elastic elements by exercising a force impact on them as well as automatic data collection and analysis, which allows determining the stiffness coefficient and investigating simple harmonic oscillations.Methods. The developed device makes it possible to determine elasticity coefficient of the spring applying two methods – static and dynamic. The dynamic method requires strict adherence to a certain procedure of experimental stydy. In this case, the system under study is under the action of a restoring force directly proportional to the displacement, i.e. it is a simple generator of harmonic oscillations. The prototype of the experimental setup being created includes a supporting structure, a control system to which an ultrasonic distance measurement sensor is connected, and a special mobile application that allows visualizing and recording the results of measurements in a user-friendly form.Results. The developed prototype makes it possible to determine spring deformation by static and dynamic methods; the presence of a special mobile application for devices with the Android operating system allows the user to control the device from his mobile phone. The experimental device allows visualizing the obtained data graphically and export them to a file of variable values. Exported values are displayed in tabular form for further processing using statistical tools or numerical computing applications.Conclusion. To improve the quality of the educational and training process of physics students it is necessary to introduce special equipment for experimental research into the educational process. Such equipment can be applied in the studies conducted in various sections of mechanics, including kinematics, oscillatory motion, impact, elasticity, etc.

A method was developed to estimate the spread of treatment doses due to a given output measurement, time interval and action level in external photon beam radiotherapy. The method exploits empirical or simulated data of both output stability and the reproducibility of the absolute output measurements and relative constancy checks. The spread of an output and the probability that an output is outside the predefined tolerance limits were estimated for different quality control procedures of the output. The use of internationally recommended output measurement intervals of 3, 1 and 0.25 months together with an action level of ±2% results in the out-of-tolerance probability up to 49%, 26% and 3%, respectively, while the output is kept within up to ±5.5%, ±4.0% and ±2.0%, respectively. It was also found that the action level has more prominent relative influence than the measurement interval. The results suggest that similar treatment quality can be achieved by doubling the output measurement time interval and lowering the action level from ±2% to ±1.5% and the constancy check action level from ±3% to ±2%.

The accuracy and reproducibility of indirect measurement of cardiac output at rest by the carbon dioxide rebreathing (indirect Fick) method with an automated respiratory analysis system (Gould 9000IV) were compared with simultaneous measurements made in duplicate by dye dilution and thermodilution in 25 patients having cardiac catheterisation studies. Measurements of cardiac output by the carbon dioxide rebreathing method were not significantly different from those obtained with dye dilution (mean difference -0.3 l/min, SD 0.76, 95% confidence interval -0.7 to 0.1). Thermodilution significantly over-estimated cardiac output by a mean of 2.2 l/min or 39% (SD 1.5, 95% confidence interval 1.6 to 2.8) compared with the carbon dioxide rebreathing method and significantly overestimated cardiac output by 1.9 l/min or 31% (SD 1.2, 95% confidence interval 1.2 to 2.5) compared with dye dilution. The reproducibility of measurements of cardiac output in individual patients was satisfactory with the dye dilution method but was poor with carbon dioxide rebreathing and thermodilution. Indirect measurement of resting cardiac output by the Gould 9000IV automated carbon dioxide rebreathing method is more accurate but the variability inherent with this method requires that multiple measurements be taken for each determination. Measurement of cardiac output by the thermodilution method by a commercially available cardiac output computer was not satisfactory because not only was there considerable variability between repeat measurements but the method also consistently overestimated cardiac output compared with the dye dilution method.

This study presents a dynamic equivalent method of wind farms with permanent magnetic synchronous generator (PMSG) wind turbines for power system stability analysis. First, a novel clustering indicator is set up based on the morphology similarity distance and cosine similarity between trajectories with the measurable output characteristics time series of wind turbines, and the K‐means algorithm is applied to cluster the PMSGs. Combining silhouette coefficient, the robustness analysis of the clustering method under different scenarios is adopted. In each cluster, a trajectory sensitivity based key parameters selection is introduced to reduce the control parameters to be identified. Moreover, a multi‐objective adaptive function is established and the multi‐controllers aggregated parameters are optimised by adaptive evolutionary particle swarm optimisation algorithm. Thus, a wind farm model represented by multi equivalent wind turbines is obtained. The IEEE 39‐bus system with a PMSG‐based wind farm is used as test system to verify the validity of the proposed dynamic equivalent approach in time domain and frequency domain, respectively. It has been demonstrated that the proposed model can reduce the model complexity and improve the calculation efficiency of wind farms.

The vulnerability of microhylid frogs, Cophixalus spp., to climate change in the Australian Wet Tropics

The paper presents experimental data of breakdown voltage as a function of voltage increase rate for nitrogen-filled tubes at pressures of 133 and 399 Pa. By fitting this data using polynomial approximation, static breakdown voltages for these tubes were estimated. The influence of voltage increase rate, voltage step, time interval between successive voltage step, and relaxation time on the static breakdown voltage was analyzed. The processes in gas advanced during breakdown were also analyzed, as well as their influence on the breakdown voltage.

A novel dynamic modeling method of defective four-row roller bearings considering the spatial contact correlation between the roller and defect zone

Chapter 9 - Variable Conversion Elements

Aerodynamic force measurement in high-enthalpy flow is very important for the design and optimization of hypersonic vehicles. Currently, impulse facilities are used for generating high-temperature and high-pressure driving gas to simulate the high-enthalpy flow with hypersonic flight-conditions, such as a shock tunnel. However, when force tests are conducted in an impulse facility, the inertial force has a large influence on the measuring results, which creates low-frequency vibrations of the test model and its motion cannot be addressed through digital filtering. In the case of a few milliseconds of test time, the structural design of the six-component balance is greatly challenged. Therefore, dynamic calibration becomes very important for improving the precision and accuracy of force measurement during short-duration. A new method, deep-learning-based single-vector dynamic self-calibration of the force measurement system, and intelligent force measurement system are proposed for obtaining high-accurate aerodynamic force in impulse facilities. One of the main features of this dynamic calibration method is the calibration of the overall force measurement system, not just the balance. Applying this method, the calibrated force measurement system is the wind tunnel test object, which ensures the consistency of calibration and application. In the evaluation, the test verification has achieved relatively ideal results, the large-scale low-frequency vibration interference has been basically eliminated, and the accuracy and reliability of the force measurement in impulse facility have been greatly improved.

The IC Profiler (ICP) manufactured by Sun Nuclear Corporation (SNC) is an ionization chamber (IC) array used for linear accelerator dosimetry measurements. Previous work characterized response of the ICP under various conditions, but there is limited work of its implementation into monthly QA measurement procedures. This work quantifies ICP accuracy and variables that affect accuracy for beam output measurements, and demonstrates feasibility of using the ICP for all recommended monthly dosimetry measurements. A total of 1985 output measurements on six Varian TrueBeam and Edge linear accelerators were performed using three ICP with quad wedges (QWs) and were compared with conventional IC measurements. The accuracy of the ICP for beam output was characterized as the difference between the ICP and IC. Variables that affect ICP accuracy, including gain settings, calibrations, and template baselining as well as machine or energy-specific bias were investigated. Measurements of profile constancy, energy, dose rate constancy, wedge factors, and gating were performed. The initially observed mean output difference between the ICP and IC was 0.16% (0.61%). When gain settings were optimized, the output difference accuracy improved to -0.02% (0.38%). The output accuracy of the ICP was not dependent on array, dose, temperature and pressure calibrations, or template baselining. Statistically, ICP output accuracy was dependent on machine and beam energy, but clinically, all measurements fell within 0.5% of unity. ICP measurements of energy, dose rate constancy, and wedge factors matched passing results with conventional IC in water measurements. Gating and beam profile constancy measurements demonstrated good stability using the ICP. Finally, monthly dosimetry QA using ICP was completed in an average of 33 min compared to 66 min using the IC. This work demonstrated the feasibility and efficiency of using the ICP, with specific considerations, as a measurement device for dosimetric linear accelerator monthly QA.