Non-contact measurement and multi-objective analysis of drilling temperature when drilling B_4C reinforced aluminum composites

Non-contact measurements of machining temperatures were performed with optical pyrometer when drilling particle（B4C） reinforced metal matrix composites（MMCs） with different drills. The effect of particle content, cutting speed, feed rate and tool material on the maximum drilling temperature was investigated. The drilling parameters were optimized based on multiple performance characteristics in terms of the maximum cutting temperature and tool wear. According to the results, the most influential control factors on the cutting temperatures are found to be particle fraction, feed rate and interaction between the cutting speed and particle content, respectively. The influences of the cutting speed and drill material on the drilling temperature are found to be relatively lower for the used range of parameters. Minimum cutting temperatures are obtained with lower particle fraction and cutting speed, with relatively higher feed rates and carbide tools. The results reveal that optimal combination of the drilling parameters can be used to obtain both minimum cutting temperature and tool wear.

Research on Non-Contact Weak Current Detection Technology

With the continuous development of industrial technology, the weak current plays an increasingly important role in all fields of life. In order to facilitate the user to carry, the study of contactless weak current measurement technology is also emerging. This article’s design idea is based on two-dimensional reluctance sensor device built non-contact weak current detection system. The system uses the reluctance sensor HMC1002 to collect the current signal and the temperature sensor DS18B20 to compensate the temperature. The signals collected by the reluctance sensor and the temperature sensor are extremely weak. After being amplified by the amplifying circuit, the signal is conducive to subsequent detection and processing. Filter circuit can filter out interference signals to achieve the goal of improving accuracy. After the corresponding algorithm of the microcontroller will convert the signal voltage, easy to read and store, thus designing a non-contact current measurement capable of detecting weak currents and achieving higher accuracy.

Study on body temperature detection of pig based on infrared technology: A review

Body temperature is an important physiological indicator in the whole process of pig breeding.Temperature measurement is also an effective means to assist in disease diagnosis and pig health monitoring.In the conventional method of measuring body temperature,a mercury column is used to obtain the rectal temperature.The operation of thismethod is complicated and requires a large amount of labor.This kind of temperature measurement method is contact and canmake the pig stressed,which is disadvantageous for the healthy growth of pigs.Therefore,rectal temperaturemeasurement no longer meets the needs of the large-scale pig industry in China's welfare agriculture.In recent years,the emerging pig body temperature detection technologies are electronic temperaturemeasurement technology,infrared temperature measurement technology and so on.Infrared temperature measurement technology has been the main means of measuring the temperature of pig body surface with its advantages of non-contact,long distance and real-time.At present,infrared temperature measurement technology and infrared image processing technology used in pig breeding are still in the exploration stage.Nowadays,the infrared temperature measurement equipment based on point-by-point analysis represented by infrared thermometer and temperature measurement equipment based on full-field analysis represented by infrared thermal imager have been applied to pig breeding industry.These types of temperaturemeasurement are more in line with the needs of the pig breeding industry to transform and upgrade to the automation,in line with the development concept of welfare farming and smart agriculture,and its development prospects are very impressive.

Junction temperature measurement of alternating current light-emitting-diode by threshold voltage method

Junction temperature of alternating current light-emitting-diode （AC-LED） has a significant effect on its stable light output and lifetime. The threshold voltage measurement is employed to characterize the junction temperature of AC-LED, due to its excellent merits in high efficiency and accuracy. The threshold voltage is measured when the driving current of an AC-LED rises to a reference on-set value from the zero-crossing node. Based on multiple measurements of threshold voltage at different temperatures, a linear relationship was uncovered between the threshold voltage and the junction temperature of AC- LED with the correlating factor of temperature sensitive parameter （TSP）. Thereby, we can calculate the junction temperature with the TSP and threshold voltage once the AC-LED stays at thermal equilibrium state. The accuracy of the proposed junction temperature measurement technique was found to be ＋3.2℃ for the reference current of 1 mA. It is concluded that the method of threshold voltage is accurate and simple to implement, making it highly suitable for measuring the junction temperature of AC-LED in industry.