No. 1

       Measurement of Physical Quantities

    Pages

Predrag B. Petrović, Maria Vesna Nikolić, Mihajlo Tatović:

New Electronic Interface Circuits for Humidity Measurement Based on the Current Processing Technique

Abstract: 

The paper describes a new electronic conditioning circuit based on the current-processing technique for accurate and reliable humidity measurement, without post-processing requirements. Pseudobrookite nanocrystalline (Fe₂TiO₅) thick film was used as capacitive humidity transducer in the proposed design. The interface integrated circuit was realized in TSMC 0.18 μm CMOS technology, but commercial devices were used for practical realization. The sensing principle of the sensor was obtained by converting the information on environment humidity into a frequency variable square-wave electric current signal. The proposed solution features high linearity, insensitivity to temperature, as well as low power consumption. The sensor has a linear function with relative humidity in the range of Relative Humidity (RH) 30-90 %, error below 1.5 %, and sensitivity 8.3 x 10¹⁴ Hz/F evaluated over the full range of changes. A fast recovery without the need of any refreshing methods was observed with a change in RH. The total power dissipation of readout circuitry was 1 mW.

Baofeng He, D. Patrick Webb, Jon Petzing:

Areal Surface Texture Parameters for Copper/Glass Plating Adhesion Characteristics

Abstract: 

Glass as an alternative printed circuit board material and interposer has been investigated for use in the micro-electronics industry. Electroless copper plating is used to provide the conductive layer, but there is limited understanding of how the surface topography of the glass substrate affects the copper/glass bonding strength exhibited in the current literature. A laser ablation technique was used to prepare glass surfaces with micro-scale structured features in this study, and these features were characterized quantitatively using areal surface texture parameters. The copper/glass bonding adhesion strength was quantified using a scratch testing technique, and the relationships between the critical loads measured and the areal surface parameters, as well as discussion of the underlying mechanisms, are presented in this report. Statistical analysis was employed to identify the most relevant areal parameters that may be used for prediction of the copper/glass bonding strength and for design of adhesion promoting surface textures. The experimental results suggest that the most significant areal surface texture parameters to consider are Sq, Sdq, Sdr, Sxp, Vv, Vmc, and Vvc, and the recommended value range for each parameter for optimal plating adhesion performance is given.

Xiaolei Wang, Huiliang Cao, Yuzhao Jiao, Taishan Lou, Guoqiang Ding, Hongmei Zhao, Xiaomin Duan:

Research on Novel Denoising Method of Variational Mode Decomposition in MEMS Gyroscope

Abstract: 

The noise signal in the gyroscope is divided into four levels: sampling frequency level, device bandwidth frequency level, resonant frequency level, and carrier frequency level. In this paper, the signal in the dual-mass MEMS gyroscope is analyzed. Based on the variational mode decomposition (VMD) algorithm, a novel dual-mass MEMS gyroscope noise reduction method is proposed. The VMD method with different four-level center frequencies is used to process the original output signal of the MEMS gyroscope, and the results are analyzed by the Allan analysis of variance, which shows that the ARW of the gyroscope is increased from 1.998*10^-1°/√h to 1.552*10^-4°/√h, BS increased from 2.5261°/h to 0.0093°/h.

Yuanlu Li:

Signal Smoothing with Time-Space Fractional Order Model

Abstract: 

The time-space fractional-order model (TSFOM) is a generation of the classical diffusion model which is an excellent smoothing method. In this paper, the fractional-order derivative in the model is found to have good performance for peak-preserving. To check the validity and performance of the model, some noisy signals are smoothed by some commonly used smoothing methods and results are compared with those of the proposed model. The comparison result shows that the proposed method outperforms the classical nonlinear diffusion model and some commonly used smoothing methods.

Peng Chen, Qin Chen, Zhijun Xie, Xiaohui Chen, Shaomei Zhao:

A Frequency-Time Algorithm of Parameter Estimation for Sinusoidal Signal in Noise

Abstract: 

In this paper, a computationally efficient and high precision parameter estimation algorithm with frequency-time combination is proposed to improve the estimation performance for sinusoidal signal in noise, which takes the advantages of frequency- and time-domain algorithms. The noise influence is suppressed through spectrum analysis to get coarse frequency, and the fine frequency is obtained by de-noising filtering and using linear prediction property. Then, estimation values of the amplitude and initial phase are obtained. The numerical results indicate that the proposed algorithm makes up for the shortcomings of frequency- and time-domain algorithms and improves the anti-interference performance and parameter estimation accuracy for sinusoidal signal.

Petr Skočík, Martin Pospíšilík, Vojtěch Křesálek, Milan Adámek:

Indirect Measurement of Shielding Effectiveness of an Enclosure for a Security Camera

Abstract: 

This paper presents the results of our experiment, which consisted in measurement of the shielding effectiveness of a camera enclosure that was designed and constructed in order to increase the susceptibility of a camera against external electromagnetic fields. All activities, from defining of requirements to final design and measurements, were performed in the Laboratory of Electromagnetic Compatibility at the Faculty of Applied Informatics of Tomas Bata University in Zlín. The hereby described approach allowed to utilize standardized laboratory equipment that is normally used for device susceptibility test to radiated electric field. The measurement was made inside a semi-anechoic room additionally damped by absorbers placed on its floor. When configuring the experiment, relevant EMC standards EN 55016 and EN 61000-4-3 were considered. Although the uncertainty tolerances, allowed by the relevant standards, were quite high for measurements in such rooms, the results obtained by the experiment matched the theoretical expectations quite satisfactorily.

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     Measurement of Physical Quantities

Marek Vagaš, Ján Semjon, Alena Galajdová, Dušan Šimšík, Róbert Rákay,    Patrik Šarga, Martin Višňovský:

Testing of Selected Accuracy Parameters for the Single Axis Positioner at the Automated Workplace

Abstract: 

Although some authors realized various measurement techniques and relevant standards in the experimental verification, the existing contributions still did not mention more complex automated workplaces with industrial robotic arm participation. To solve this, we provide a different view of the interconnection between individual devices (positioner, robot, etc.) controlled by third-party methods (Siemens products). Also, to obtain the necessary effectiveness, we tested and verified selected accuracy parameters for the participating device component (positioner). The proposed work tries to fulfill expectations for a precise welding technology (to ensure simultaneous movements of both the industrial robotic arm and positioner) to achieve higher quality and better productivity, although the components are from different manufacturers.

Boris Širaiy, Vladimir Ilić, Lazar Toskić:

Usability of Wireless ECG Body Sensor for Cardiac Function Monitoring During Field Testing

Abstract: 

Wireless ECG body sensor Savvy is a feasible solution for reliable and accurate long-term heart rhythm monitoring. However, there were no studies dealing with usability of this sensor in field testing. Accordingly, the aim of the study is to evaluate the quality of the ECG signal measured with wearable wireless ECG body sensor when used in field test settings and to determine how different types of sensor fixation affects the quality of the ECG signal during sub-maximal and maximal running settings. Twenty-three participants, 10 females and 13 males, were included in the study (20.56 ± 1.19 years). All subjects performed shuttle run (SR), Cooper 2400 m (C), and 100 m sprint test (S), once wearing the sensor attached to self-adhesive skin electrodes, additionally fixed with self-adhesive tapes, and secondly with the sensor attached to Polar belt and strapped around the chest. Test outcomes were compared applying the Student t-test for dependent variables, or the non-parametric Wilcoxon test, depending on the results of the normality test. The results showed a significant difference (p<0.05) in the running speed that provides an assessable ECG signal between two different types of fixation in all three running tests – C, S, SR, as well as between the parameters “QRS detected as negative”, “correct software detection”, and “detected QRS” in the C and SR tests. Findings obtained in this study proved that if properly fixed, the ECG signal recorded with wireless ECG can be efficiently used for heart monitoring during physical activities in real setting and potentially could be used as additional tool in detection of cardiovascular diseases. In addition, fixation with Polar belt is more adequate for measurements made during physical activity in real setting compared to fixation with tape.

Erhan Tiryaki, Özlem Kocahan, Serhat Özder:

An Improved Method for Determination of Refractive Index of Dielectric Films from Reflectance Spectrum by Using the Generalized Morse Wavelet

Abstract: 

The Generalized Morse Wavelet (GMW) algorithm was adapted to determine the refractive index of dielectric film from the reflectance spectrum. A theoretically generated reflectance spectrum in the range of 300-1200 nm wavelength was analyzed by the Continuous Wavelet Transform (CWT) and the refractive index dispersion was obtained by the mentioned method. In addition, a noisy reflectance spectrum was analyzed to show the advantages of the CWT method. Refractive index dispersions calculated by the Morlet and the Paul wavelet were compared to GMW at the end of the study.

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Measurement of Physical Quantities

Kang Zhang, Xiaorui Niu, Yunjiao Ma, Xiangmin Chen, Lida Liao, Jiateng Wu:

A New Demodulation Method for Mechanical Fault Feature Extraction based on LOD and IEE

Abstract: 

The rolling bearing and gear fault features are generally shown as modulation characteristics of their vibration signals. The empirical envelope (EE) method is an accordingly common demodulation method. However, the EE method has the defects of over- and undershoot, which may lead to demodulation error. According to this, an envelope optimization algorithm -- empirical optimal envelope (EOE) is introduced into the EE method, and an improved empirical envelope (IEE) method is obtained to calculate the instantaneous amplitude and instantaneous frequency of mono-component modulation signal. Furthermore, aiming at the actual measured mechanical vibration signal has multi-component modulation feature, the IEE method is combined with an adaptive signal decomposition method -- local oscillatory characteristic decomposition (LOD) proposed by the author, thereby a new multi-component signal demodulation method based on LOD and IEE is proposed. The proposed method is compared with Hilbert transform (HT) and Teager energy operator (TEO) demodulation methods by the simulation signal and actual measured mechanical vibration signal. The results show that the demodulation effects including edge effects, negative frequency, over- and undershoot of the proposed method are significantly improved and can extract the rolling bearing and gear fault feature information clearly.

Baofa Hu, Zhiwei Li, Yuanjie Wan, Peng Zhou, Chunquan Zhang, Haisheng San:

3D Printed Pressure Sensor Based on Surface Acoustic Wave Resonator

Abstract: 

This paper reports a 3-dimentional (3D) pressure sensor based on surface acoustic wave (SAW) resonators. The SAW resonators were designed and fabricated on 128°Y-X LiNbO₃ substrate using the MEMS technology. The pressure sensing structure was 3D-printed using polyactic acid plastic, and two SAW resonators were integrated in the 3D-printed chamber structure for both temperature and pressure sensing. The SAW-based gas pressure sensors demonstrate a sensitivity of 589 ppm/MPa at the pressure range of 100-600 kPa and temperature of 40 °C.  

Mochao Pei, Hongru Li, He Yu:

Degradation State Identification for Hydraulic Pumps Based on Multi-scale Ternary Dynamic Analysis, NSGA-II and SVM

Abstract: 

Degradation state identification for hydraulic pumps is crucial to ensure system performance. As an important step, feature extraction has always been challenging. The non-stationary and non-Gaussian characteristics of the vibration signal are likely to weaken the performance of traditional features. In this paper, an efficient feature extraction algorithm named multi-scale ternary dynamic analysis (MTDA) is proposed. MTDA reconstructs the phase space based on the given signal and converts each embedding vector into a ternary pattern independently, which enhances its capacity of describing the details of non-stationary signals. State entropy (SE) and state transition entropy (STE) are calculated to estimate the dynamical changes and complexity of each signal sample. The excellent performance of SE and STE in detecting frequency changes, amplitude changes, and the development process of fault is verified with the use of four simulated signals. The proposed multi-scale analysis enables them to provide a more precise estimation of entropy. Furthermore, support vector machine (SVM) and nondominated sorting genetic algorithm II (NSGA-II) are introduced to conduct feature selection and state identification. NSGA-II and SVM can conduct the joint optimization of these two goals. The details of the method proposed in this paper are tested using simulated signals and experimental data, and some studies related to the fault diagnosis of rotating machinery are compared with our method. All the results show that our proposed method has better performance, which obtains higher recognition accuracy and lower feature set dimension.

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Measurement of Physical Quantities

Adam Kotowski:

A Method for Improving the Accuracy of Natural Frequency Measurement Using In-the-loop Computing

Abstract: 

The method presented in the paper is based on in-the-loop computing applied for impulse response to obtain a spectrum with a much higher frequency resolution than using FFT. Then, higher spectrum frequency resolution results in greater accuracy in estimation of natural frequencies. The frequency resolution of estimated spectrum in this method is completely independent of the length of impulse response and, by extension, the method eliminates the problem of spectral resolution limitation using FFT due to finite length of recorded signals. This fact is very useful and is the main advantage of the proposed method. The results of the method have been shown and compared in quantitative terms to natural frequencies estimated using classical FFT with zero-padding as reference method.

Siquan Zhang:

Analytical Model of an I-core Coil for Nondestructive Evaluation of a Conducting Cylinder below an Infinite Plane Conductor

Abstract: 

An analytical model for eddy current testing of an I-core coil located above a two-layer conductive material is presented. The upper layer is an infinite plane conductor, and the bottom layer is a conductive cylinder. The method of truncated region eigenfunction expansion (TREE) is used to solve this axisymmetric problem. First the magnetic vector potential of a filamentary coil coaxial with the I-core over the two-layer conductor is considered. Then the closed form expression for the impedance of the multi-turn coil with rectangular cross section is derived by using the principle of superposition from the filamentary coil field. For frequencies ranging from 0.1 kHz to 10 kHz, both the impedance changes of the I-core coil located above the infinite plane conductor without the conducting cylinder, and in the absence of the two-layer conductor are calculated using Mathematica, respectively. The influence of the conducting cylinder below the infinite plane conductor on the impedance change is analyzed. The analytical calculation results are verified by the finite element method and experiment, the results agree very well, which verifies the correctness of the analytical model.

Ling-Xiang Liu, Zhong-Tai Qian:

True Cause for Multi-Layer Inductive Coils’ Sensitivity to Ambient Relative Humidity

Abstract: 

For analyzing the properties of humidity-effect on the measurement of the inductance of multi-layer coils, a formula that establishes an approximate relationship between the coil’s inherent capacitance and interlayer parasitic capacitance has been derived. Such a derivation using the inductor’s equivalent circuit to include humidity effects clarifies the characterization of inductance, after more than half a century of neglect in the literature.

Sreelekha Panda, Abhishek Das, Satyasis Mishra, Mihir Narayan Mohanty:

Epileptic Seizure Detection using Deep Ensemble Network with Empirical Wavelet Transform

Abstract: 

Epileptic seizure attack is caused by abnormal brain activity of human subjects. Certain cases will lead to death. The detection and diagnosis is therefore an important task. It can be performed either by direct patient activity during seizure or by electroencephalogram (EEG) signal analysis by neurologists. EEG signal processing and detection of seizures using machine learning techniques make this task easier than manual detection. To overcome this problem related to a neurological disorder, we have proposed the ensemble learning technique for improved detection of epilepsy seizures from EEG signals. In the first stage, EEG signal decomposition is done by utilizing empirical wavelet transform (EWT) for smooth analysis in terms of sub-bands. Further, features are extracted from each sub. Time and frequency domain features are the two categories used to extract the statistical features. These features are used in a stacked ensemble of deep neural network (DNN) model along with multilayer Perceptron (MLP) for the detection and classification of ictal, inter-ictal, and pre-ictal (normal) signals. The proposed method is verified using two publicly available datasets provided by the University of Bonn (UoB dataset) and Neurology and Sleep Center - New Delhi (NSC-ND dataset). The proposed algorithm resulted in 98.93 % and 98 % accuracy for the UoB and NSC-ND datasets, respectively.

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Measurement of Physical Quantities

Wiesław Szaj, Wiktoria Wojnarowska, Bogdan Pajdo:

First Evaluation of the PTN-104 Plethysmographic Sensor for Heart Rate

Abstract:

The purpose of this study was to examine the accuracy of HR measurements by the PTN-104 sensor in comparison to the fingertip pulse oximeter, which is a photoplethysmographic sensor (PPG). Twelve healthy participants underwent the same protocol during a single visit. Measurements were taken after each participant completed an initial rest period of 5 minutes and after 1-minute of exercising comprising of 30 squats. Each subject had the PTN-104 sensor attached to the index finger and a fingertip pulse oximeter to the opposite one. When examining the data in aggregate, there was a strong correlation between the PTN-104 sensor and PPG for HR (r = 0.988) with a mean bias of -2.55 bpm (95% LoA +5.0, -10.1). The PTN-104 sensor satisfied validity criteria for HR monitors, however, showed a lower accuracy for measurements at rest, which is surprising. Due to the noticed limitations, this study should be repeated with a larger group of subjects and the PTN-104 sensor should be compared to the gold standard method for measuring HR, which is ECG.

Mochao Pei, Hongru Li, He Yu:

A Novel Three-stage Feature Fusion Methodology and its Application in Degradation State Identification for Hydraulic Pumps

Abstract:

The performance of feature is essential to the degradation state identification for hydraulic pumps. The initial feature set extracted from the vibration signal of the hydraulic pump is often high-dimensional and contains redundant information, which undermines the effectiveness of the feature set. The novel three-stage feature fusion scheme proposed in this paper aims to enhance the performance of the original features extracted from the vibration signal. First, sparse local Fisher discriminant analysis (SLFDA) performs intra-set fusion within the two original feature sets, respectively. SLFDA has a good effect on samples with intra-class multimodality, and the feature set fused by it has obvious multivariate normal distribution characteristics, which is conducive to the next fusion. Second, our modified intra-class correlation analysis (MICA) is used to fuse two feature sets in the second stage. MICA is a CCA (Canonical correlation analysis) -based method. A new class matrix is used to modify the covariance matrix between two feature sets, which allows MICA to conveniently inherit the discriminating structure while fusing features. Finally, we propose a feature selection algorithm based on kernel local Fisher discriminant analysis (KLFDA) and kernel canonical correlation analysis (KCCA) to select the desired features. This algorithm based on Max-Relevance and Min-Redundancy (mRMR) framework solves the problem that CCA cannot properly evaluate the correlation between features and the class variable, as well as accurately evaluates the correlation among features. Based on the experimental data, the proposed method is compared with several popular methods, and the feature fusion methods used in some previous studies related to the fault diagnosis of rotating machinery are compared with it as well. The results show that the fusion effectiveness of our method is better than other methods, which obtains higher recognition accuracy.

Przemysław Otomański, Eligiusz Pawłowski , Anna Szlachta:

The Evaluation of Expanded Uncertainty of DC Voltages in the Presence of Electromagnetic Interferences using the LabVIEW Environment

Abstract:

The paper presents a possible application of integrated LabVIEW environment to the final evaluation of measurement results in direct measurement. The possibilities of presenting and visualizing the uncertainty of measurement results in a convenient and user-friendly form are also discussed. The topics discussed in the paper were presented using a developed application in LabVIEW. The paper discusses the topic of measurement of direct voltages in the presence of strong electromagnetic interferences. These problems are frequently omitted or hardly emphasized.  It presents a suitable measuring system, a virtual measuring instrument created in the LabVIEW environment, and the results of tests carried out for an example NI PCI-6221 data acquisition board. The described approach can be applied also in other measurement situations.

Jelena Jovanović, Dragan Denić:

Mixed-mode Method Used for Pt100 Static Transfer Function Linearization

Abstract:

Pt100 is a resistance temperature detector characterized by a relatively linear resistance/temperature relationship in a narrow temperature range. However, the Pt100 sensor shows a certain degree of static transfer function nonlinearity of 4.42 % in the range between -200 °C and 850 °C, which is unacceptable for some applications. As a solution to this problem, a mixed-mode linearization method based on a special dual-stage piecewise linear ADC design is proposed in this paper. The first stage of the proposed dual-stage piecewise linear ADC is performed with a low-complex and low-power flash ADC of a novel sequential design. The novelty of the proposed sequential design is reflected in the fact that the number of employed comparators is equal to the flash ADC resolution. The second stage is performed with a delta-sigma ADC with a differential input and differential reference. Using the 6-bit flash ADC of novel design and the 24-bit delta-sigma ADC, the nonlinearity error is reduced to 2.6·10^-3 %, in the range between -200 °C and 850 °C. Two more ranges are examined, and the following results are obtained: in the range between 0 °C and 500 °C, the nonlinearity error is reduced from 1.99 % to 5·10^-4 %, while in the range between -50 °C and 150 °C, the nonlinearity error is reduced from 0.755 % to 2.15·10^-4 %.

Maciej Jakubczak, Jacek Kurzyna, Arsenii Riazantsev:

Experimental Verification of the Magnetic Field Topography inside a small Hall Thruster

Abstract:

The magnetic circuit of a 500 W class Hall thruster, an electric propulsive device for spacecraft, was characterized experimentally and the results compared with simulation in order to verify the design. The commercial 3D gaussmeter, which was used in this work, was additionally recalibrated to compensate for translation and rotation of individual Hall sensors inside the probe. The Stokes stream function approach was applied to reconstruct the magnetic field topography in the thruster. The procedure, carried out on four different cases, yielded very good agreement between simulations and measurements, even for cusped configurations. Presented technique could be used as a robust method of verification of new magnetic circuit designs not only for Hall thrusters but also for a wide class of plasma devices for which detailed knowledge about actual distribution of magnetic field is crucial for optimization.

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Measurement of Physical Quantities

Branko Štrbac, Dragan Rodić, Milan Delić, Borislav Savković, Miodrag Hadžistević:

Investigation of Functional Dependency between the Characteristics of the Machining Process and Flatness Error Measured on a CMM

Abstract:

Numerous studies have shown that the choice of measurement strategy (number and position of measurement points) when measuring form error on a coordinate-measuring machine (CMM) depends on the characteristics of the machining process which was used to machine the examined surface. The accuracy of form error assessment is the primary goal of verification procedures and accuracy is considered perfect only in the case of the ideal verification operator. Since the ideal verification operator in the “point-by-point” measuring mode is almost never used in practice, the aim of this study was to examine a relationship which had not been examined in earlier studies, namely how the machining process, surface roughness and a reduced number of points in the measurement strategy affect the accuracy of flatness error assessment. The research included four most common cutting processes applied to flat surfaces divided into nine different classes of roughness. In order to determine functional dependency between the observed input variables and the output, statistical regression models and neuro-fuzzy logic (artificial intelligence tool) were used. The analyses confirmed the significance of all three input parameters, with surface roughness being the most significant one. Both the statistical regression models and neuro-fuzzy models proved to be adequate, matching the experimental results. The use of these models makes it possible to determine flatness error measured on a CMM if input variables considered in the paper are known.

Kiril Demerdziev, Vladimir Dimchev:

Analysis of Errors in Active Power and Energy Measurements Under Random Harmonic Distortion Conditions

Abstract:

As harmonic distortion of voltage and current is reality in the power system, the need for accurate measurement of electrical power and energy goes beyond the instruments’ specifications and calibration procedures regarding pure sine wave signals. Several international standards and recommendations provide test signals for examination of electricity meters under non-sinusoidal conditions, however, not all of the test signal parameters’ possible states are faithfully represented in those documents. Because the high order harmonics may possess random amplitudes and phase shifts in relation to components at fundamental frequency, it is important that the meter’s performance is verified with random waveforms as well. The non-linear dependence between the measured power/energy and the phase shifts, both between fundamental and harmonic components, provides additional complexity of such an analysis. Simple test signals, which are in accordance with the standards’ demands and propositions, are used for determination of the measurement error in case of different harmonic distortion parameter change. In order for a general error function for any measurement device to be determined, mathematical modelling, regarding the results from multiple tests, is performed. The mathematical model presents a strong dependence between a single component’s phase shifts and a meter’s error and it provides a systematization of all signal parameters’ influence on the measurement accuracy.

Sichen Fan, Jun Ruan, Dandan Liu, Xinliang Wang, Fan Yang, Yong Guan, Hui Zhang, Junru Shi, Yang Bai, Shougang Zhang:

Phase Variation Measurement in Mach–Zehnder Interferometric Switch

Abstract:

Phase variations of the interrogation field lead to frequency shifts in Ramsey-type atomic clocks. This paper reports the development of a 300 MHz Mach–Zehnder (MZ) switch that effectively suppresses phase-transient effects. Similar to MZ interferometers, this radio-frequency (RF) MZ switch comprises two arms that are power- and phase-matched with each other. By inserting a PIN diode RF switch in one arm, the other arm remains undisturbed, freeing it of the phase transient. Trigger phase fluctuation measurements are implemented by using a lock-in amplifier to extract the in-phase and quadrature (I/Q) demodulation data. The results show that the extinction ratio of the RF MZ switch phase fluctuations is <5 μrad, which is significantly lower than that of a PIN (50 μrad). When applied to a cesium fountain clock, the RF MZ switch produces a frequency shift better than 1.73 × 10⁻¹⁶.

Krzysztof Dziarski, Arkadiusz Hulewicz:

Uncertainty of Thermographic Temperature Measurement with an Additional close-up Lens

Abstract:

The thermographic temperature measurement is burdened with uncertainty. This non-contact temperature measurement method makes it possible to measure the temperature of the electrical device under load. When the observed object is small (a few square millimeters) the spatial resolution of the thermographic cameras is often insufficient. In this case, the use of the additional macro lens is needed. After using an additional lens, the uncertainty of the thermographic measurement is different from the uncertainty of thermographic measurement without an additional lens. The values of the uncertainty contributions depend on the conditions during the measurement and the used methodology. The authors constructed an uncertainty budget of thermographic temperature measurement with an additional macro lens, based on EA-4/02 (European Accreditation publications). The uncertainty contributions were also calculated. On the basis of the calculated values of the uncertainty contributions, it was determined which factor had the greatest impact on the value of the thermographic temperature measurement with an additional lens.

Liping Tian, Lingbin Shen, Lin Chen, Lili Li, Jinshou Tian, Ping Chen, Wei Zhao:

A New Design of Large-format Streak Tube with Single-lens Focusing System

Abstract:

Streak tubes with large-format and high spatial resolution are central to mm-spatial-resolved STIL detection system and hyperspectral resolved ICF experiment. In this paper, we established a large-format streak tube with a three-coaxial-cylindrical single-lens focusing system, a spherically curved photocathode and phosphor screen model in CST Particle Studio. The temporal and spatial resolution were calculated and mimicked based on the Monte-Carlo sampling method in static and dynamic mode. The simulated results show that the static spatial resolution reaches 50 lp/mm over the whole 50 mm effective photocathode length, and the physical temporal resolution is better than 45 ps. Furthermore, in dynamic working mode, the streak tube can achieve spatial resolution of 10 lp/mm and temporal resolution of 60 ps. The simulation results provide a comprehensive guidance for the design and production of large-format high spatial resolution streak tubes.

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Jun Che, Yanxia Sun, Xiaojun Jin, Yong Chen:

3D Measurement of Discontinuous Objects with Optimized Dual-frequency Grating Profilometry

Abstract:

Three-dimensional profilometry tends to be less effective at measuring discontinuous surfaces. To overcome this problem, an optimized profilometry based on fringe projection is proposed in this paper. Due to the limitation of the shooting angle, there are projection blind spots on the surface of discontinuous objects. Since the noises and unwrapping errors are always localized at the projection blind spots, an algorithm is designed to determine the blind spots automatically with the light intensity difference information. Besides, in order to improve the measurement accuracy, a processing scheme is introduced to deal with the local height distortion introduced by the dual-frequency grating profilometry. Lots of measurement tests on various surfaces are carried out to assess the optimized profilometry, and experimental results indicate that the modified profilometry system works more robust with high reliability and accuracy in measuring different kinds of surfaces, especially discontinuous ones.

Peter Andris, Tomáš Dermek, Ivan Frollo:

Calibration of NMR Receiver using Spectrometer Characteristics

Abstract:

This article describes the measurement of the relation between input and output signals using two techniques: with a signal generator and with the thermal noise of a known resistance. Each of the techniques has its advantages and disadvantages. Both methods are tested and the results are compared. The input signal of the receiver is known in volts, while the output signal is in ADC (analogue-to-digital converter) units. It is the main difference versus the gain. Knowledge of the relation enables recalculation of the output signal into the input of the receiver or vice versa. It is important in some experiments. The method with the harmonic signal requires a suitable NMR spectroscopic console, generator of the harmonic signal and an attenuator, the method with the noise requires only the NMR console. It indicates that both methods are simple and cheap. The measured data are processed on a standard PC using common programs.

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