Fast Measurement System Research Articles

Characterization of the Vaporization Inlet for Aerosols (VIA) for online measurements of particulate highly oxygenated organic molecules (HOMs)

Abstract. Particulate matter has major climate and health impacts, and it is therefore of utmost importance to be able to measure the composition of these particles to gain insights into their sources and characteristics. Many methods, both offline and online, have been employed over the years to achieve this goal. One of the most recent developments is the Vaporization Inlet for Aerosols (VIA) coupled to a nitrate Chemical Ionization Mass Spectrometer (NO3-CIMS), but a thorough understanding of the VIA–NO3-CIMS system remains incomplete. In this work, we ran a series of tests to assess the impacts from different systems and sampling parameters on the detection efficiency of highly oxygenated organic molecules (HOMs) in the VIA–NO3-CIMS system. Firstly, we found that the current VIA system (which includes an activated carbon denuder and a vaporization tube) efficiently transmits particles (> 90 % for particles larger than 50 nm) while also removing gaseous compounds (> 97% for tested volatile organic compounds – VOCs). One of the main differences between the VIA and traditional thermal desorption (TD) techniques is the very short residence time in the heating region, on the order of 0.1 s. We found that this short residence time, and the corresponding short contact with heated surfaces, is likely one of the main reasons why relatively reactive or weakly bound peroxides, for example, were observable using the VIA. However, the VIA also requires much higher temperatures in order to fully evaporate the aerosol components. For example, the evaporation temperature of ammonium sulfate particles using the VIA was found to be about 100–150 °C higher than in typical TD systems. We also observed that the evaporation of particles with larger sizes occurred at slightly higher temperatures compared to smaller particles. Another major aspect that we investigated was the gas-phase wall losses of evaporated molecules. With a more optimized interface between the VIA and the NO3-CIMS, we were able to greatly decrease wall losses and thus improve the sensitivity compared to our earlier VIA work. This interface included a dedicated sheath flow unit to cool the heated sample and provide the NO3-CIMS with the needed high flow (10 L min−1). Our results indicate that most organic molecules observable by the NO3-CIMS can evaporate and be transported efficiently in the VIA system, but upon contact with the hot walls of the VIA, the molecules are instantaneously lost. This loss potentially leads to fragmentation products that are not observable by the NO3-CIMS. Thermograms, obtained by scanning the VIA temperature, were found to be very valuable for both quantification purposes and for estimating the volatility of the evaporating compounds. We developed a simple one-dimensional model to account for the evaporation of particles and the temperature-dependent wall losses of the evaporated molecules, and we thereby estimate the concentration of HOMs in secondary organic aerosol (SOA) particles. Overall, our results provide much-needed insights into the key processes underlying the VIA–NO3-CIMS method. Although there are still some limitations that could be addressed through hardware improvements, the VIA–NO3-CIMS system is a very promising and useful system for fast online measurements of HOMs in the particle phase.

High accuracy calibration method for multi-line structured light three-dimensional scanning measurement system based on grating diffraction.

Multi-line structured light three-dimensional (3D) scanning measurement system enables to obtain the richer 3D profile data of the object simultaneously during one frame, ensuring high accuracy while structured light is deformed for the modulation by the object. Nevertheless, current calibration methods cannot fully take advantage of its high precision. In this paper, a fast and high-accuracy 3D measurement system based on multi-line lasers with a spatially precise structure via integrating a diffraction grating was proposed. This helps achieve precise calibration results of the light planes by introducing spatial constraint relations of the diffractive light, thus improving measurement accuracy. The operating principle and the workflow of the proposed system were described in detail. The measurement accuracy of the developed prototype was verified through contrastive experiments. At a working distance of 400 mm, the results show that the root mean square error (RMSE) of the proposed system is 0.083 mm, which is improved by 37.6% compared to the traditional calibration method of light planes for the ranging system. The system utilizing a grating that facilitates the integration of the device has great application value.

Fast quasi-coaxial vertical 3D measurement based on galvanometric scanner

Vertical measurement is widely studied for its ability to measure objects with drastic changes in surface shape such as deep holes and steps. This paper proposes a fast quasi-coaxial modulations-based 3D measurement system by using a galvanometric scanner, whose rotation is triggered by a field-programmable gate array (FPGA) and is synchronous with the imaging acquisition. In addition, to reduce the influence of background light on reconstruction, a segmented fitting algorithm is proposed, which can remove the background light intensity more appropriately. Experiments demonstrate the validity of the system and background light removal method proposed in this paper.

Complex illumination system for fast interferometric measurements

Freeform metrology is an enabling technology for today’s research and advanced manufacturing. The Tilted Wave Interferometer is a full field measurement system for fast and flexible measurements. It is based on an off-axis illumination scheme based on a microlens array. In this contribution, we present a novel illumination system for the tilted wave interferometer, that allows to reduce the measurement time by a factor of four using parallelization based on wavelength multiplexing. Here we present a design solution that utilizes the flexibility of 3D-printing. The microlenses are realized as multi-order diffractive optical elements, providing a high efficiency compared to colorfilter based realizations. To boost the light efficiency of the novel illumination system further, a field lens functionality is added to the system by adding individual micro-prisms to each microlens. The system is manufactured by the use of grayscale two-photon polymerisation.

Effect of temperature on evaporation dynamics of sheep's blood droplets and topographic analysis of induced patterns

To characterize various induced phenomena and the blood of healthy sheep using several parameters, the evaporation dynamics of 72 drops of sheep blood evaporated at several temperatures: 23, 37, 60, and 90 °C on glass hydrophilic substrates were studied. This allows the prediction of the sheep blood pattern, knowing the surface temperature and vice versa. To determine the variation in the Marangoni number between the center and the triple line, an infrared thermography method was used to measure the temperature variation along the surface of the drop. Simultaneously, a high-performance camera was used to measure the variation in the height of the drop during the evaporation using a superior algorithm software for image analysis, drop shape analyzer, under controlled conditions (Humidity = 40%, Tatm = 23 °C). The study of the evaporation dynamics and pattern formation shows the effect of temperature on the flow circulation inside the drop, resulting in the final deposit. The results showed two categories corresponding to two different evaporation phenomena induced by the thermal Marangoni effect. Furthermore, to transform the induced pattern of sheep blood evaporation into a 3D image, a topographic study was performed using a highly accurate, fast, and flexible optical 3D measurement system. The topographic parameters were subsequently extracted from these 3D images. The statistical study showed a good correlation between the topographic parameters and the surface temperature, and a significant difference between each temperature group for each parameter.

Study of the compression properties of welded seams formed using hot wedge, hot air, ultrasonic, and high-frequency welding techniques

The compression properties of welded seams depending on welding parameters using the hot wedge and hot air welding technique, ultrasonic welding technique, and high-frequency welding technique were studied. The compression properties, expressed by parameters such as compressional energy WC, compressional resilience RC, linearity LC, and compressibility C, are important information about the welded seam quality in terms of touch, voluminosity, stiffness, and flexibility of the welded seam. KES-FB and FAST measurement systems were used to test the compression properties of the welded seams. Based on the analysis of the results obtained, the influence of the welding parameters on the compression properties of the welded seam was determined. The results of the investigation showed that improperly selected welding parameters, such as the supply or introduction of too much heat into the material to be welded or too long exposure of the material in the weld zone to heat, result in welded seams with expressive extrusion edges, which affects the quality of the welded seams. These welded seams have very low values of compressional resilience RC and very high values of compressional energy WC and compressibility C.

Benchmarking a New Digital Data Acquisition System for Fast Neutron Metrology

The application of a CAEN DT5730 digitizer unit for fast neutron metrology is explored. Measurements were made at the Accelerator for Metrology and Neutron Applications in External Dosimetry (AMANDE) monoenergetic neutron facility of the IRSN, France, over a neutron energy range from 1.2 to 7.0 MeV using a BC501A scintillator. The DT5730 digitizer and an analog system based on NIM electronics and an MPA-3 multichannel analyzer acquisition unit were used, under identical beam conditions, for data acquisition. Several observables were compared between the two systems including the quality of pulse shape discrimination (PSD), neutron energy distribution derived from unfolding analyses, and deadtime effects over a range of beam currents from 0.1 to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5.1~\mu \text{A}$ </tex-math></inline-formula> . The suitability of the digital system for fast neutron metrology measurements both in the laboratory and in workplace fields is discussed.

A Simple Calibration Method for a Fringe Projection System Embedded within an Additive Manufacturing Machine

In additive manufacturing (AM), especially for advanced powder fusion machines, it is of high importance to develop an in situ inspection system to monitor the printed surface and pre-print powder bed as the build cycle proceeds. Consequently, high resolution, high precision and fast detection measurement systems need to be investigated, as such optically based measurement systems can provide feedback for manufacturing process optimisation. Fringe projection technology has a great advantage in the measurement of topography in such environments. The implementation of a fringe projection system requires that the system is pre-calibrated in order to obtain high measurement resolution and repeatability. This paper presents a simple calibration method for an AM-based in situ fringe projection system using a phase-depth calibration model. If a calibration plate with certificated marks is used, however, the texture of the plate will affect the measured phase accuracy. A simple calibration method to reduce the calibration plate texture effect in the process of calibration is outlined. Experimental results show that the proposed method can eliminated these effects and improve measurement resolution and repeatability. The proposed in situ/in process inspection technique has been implemented within a commercial electron beam powder bed fusion additive manufacturing machine (EBAM), to demonstrate the capability for effective feedback during the manufacturing process.

An Ultrahigh Sensitive Microwave Microfluidic System for Fast and Continuous Measurements of Liquid Solution Concentrations.

In this paper, we describe a low-cost microwave microfluidic system of ultrahigh sensitivity for detecting small changes in the concentration of polar solutions (liquid dielectrics) in the 2.4 GHz ISM band. Its principle of operation is based on microwave interferometry, which is implemented using planar microstrip lines and integrated microwave components. The key features of this system include small solution intake (<200 µL per measurement), short time of measurement (ca. 20 ms), ultrahigh sensitivity of concentration changes (up to 55 dB/%), and low error of measurement (below 0.1%). The ultrahigh sensitivity was proven experimentally by measurements of the fat content of milk. In addition, it is a user-friendly system due to an effortless and fast calibration procedure. Moreover, it can be made relatively compact (<20 cm2) and features low power consumption (200 mW). Thus, the proposed system is perfect for industrial applications, especially for highly integrated lab-on-chip devices.

Neutron beam filter system for fast neutron cross-section measurement at the ANNRI beamline of MLF/J-PARC

A neutron filtering system has been introduced in the Accurate Neutron–Nucleus Reaction Measurement Instrument (ANNRI) beamline in the Materials and Life Science (MLF) facility of the Japan Proton Accelerator Research Complex (J-PARC) in order to produce quasi-monoenergetic neutron beams. The filtered neutron spectrum by the filter assemblies was analyzed by means of capture and transmission measurements and also by Monte Carlo simulations using PHITS. The characteristics of the filtered neutron beam are discussed alongside its viability in future applications for neutron cross-section measurements in the fast neutron region.

Flexible nanocellulose-based SERS substrates for fast analysis of hazardous materials by spiral scanning

Surface-enhanced Raman scattering (SERS) has proven to be a valuable tool for assessing harmful chemicals in various substances, including water, soil, and foods. However, a fast measurement system is required for multiplexed detection to extend the range of its applications. The rotating scanning stage of the SERS substrate is considered to be a promising approach to achieving a fast measurement system. This paper reports a facile measurement system by using a flexible nanocellulose-based SERS substrate and a spiral scanning system, which rotates the cylinder sample holder and moves the stage. A flexible nanocellulose-based SERS substrate deposited with Au nanoparticles is suitable for the spiral scanning system, which requires SERS substrates to be highly flexible and durable. The well-known toxic fungicide, thiram, was tested by this system. The results revealed that the nanocellulose-based SERS substrate is well-fitted with a spiral scanning system and that the signal data from a large area substrate can be obtained within 30 s. It is noteworthy that the error of spiral scanning measurements is smaller than that of multi-spot sampling. This work provides a powerful tool for Raman spectroscopic analysis, which requires quantitative and fast testing. Furthermore, various flexible SERS substrates can be utilized in this system for toxic materials detection.

A fast and precise three-dimensional measurement system based on multiple parallel line lasers

This paper conducts a trade-off between efficiency and accuracy of three-dimensional (3D) shape measurement based on the triangulation principle, and introduces a flying and precise 3D shape measurement method based on multiple parallel line lasers. Firstly, we establish the measurement model of the multiple parallel line lasers system, and introduce the concept that multiple base planes can help to deduce the unified formula of the measurement system and are used in simplifying the process of the calibration. Then, the constraint of the line spatial frequency, which maximizes the measurement efficiency while ensuring accuracy, is determined according to the height distribution of the object. Secondly, the simulation analyzing the variation of the systemic resolution quantitatively under the circumstance of a set of specific parameters is performed, which provides a fundamental thesis for option of the four system parameters. Thirdly, for the application of the precision measurement in the industrial field, additional profiles are acquired to improve the lateral resolution by applying a motor to scan the 3D surface. Finally, compared with the line laser, the experimental study shows that the present method of obtaining 41220 points per frame improves the measurement efficiency. Furthermore, the accuracy and the process of the calibration are advanced in comparison with the existing multiple-line laser and the structured light makes an accuracy better than 0.22 mm at a distance of 956.02 mm.

Burnup measurement error analysis of HTR fuel spheres using ab-initio Monte-Carlo simulations

Multi-pass pebble-bed HTRs need a fast and efficient burnup measurement system (BUMS) for irradiated spherical fuel elements. Typically, for every single pass through the system, we are restricted to 55 h cooling time and 10 s measurement time. These restrictions make a high precision gamma spectrum collection and analysis difficult in general. Using the ab-initio Monte-Carlo simulation approach, we determine the one-sigma relative statistical uncertainty to be ±6.5% at the final 200 MWth MODUL burnup of 9.2% FIMA when the traditional gamma measurement systems are used. This FIMA uncertainty range is originated from the limiting statistics of a very short measurement time and the simultaneous interference of neighboring peaks at so short cooling times. It is the first time that the analysis contains the consideration of a 140La caused Compton shoulder which influenced the background near the Cs-137 peak. Longer cooling times would reduce peak interference and longer measurement times would allow better statistics, as would higher count rates in more advanced gamma counting systems and a narrower width of the four photopeaks in the near 137Cs spectrum. Thereby, the relative statistical error could be brought down to 2–3%, which would be better for engineers. The always existing relative statistical error which can be accepted and recommended in the real measurement should be evaluated in many aspects comprehensively.

Dynamic modulation performance of ferroelectric liquid crystal polarization rotators and Mueller matrix polarimeter optimization

A ferroelectric liquid crystal polarization rotator (FLCPR) has been widely used in polarization measurement due to its fast and stable modulation characteristics. The accurate characterization of the modulation performance of FLCPR directly affects the measurement accuracy of the instrument based on liquid crystal modulation. In this study, FLCPR is accurately characterized using a self-developed high-speed Stokes polarimeter. Strong linear and weak circular birefringence are observed during modulation processes, and all the optical parameters of FLCPR are dependent on driving voltage. A dual FLCPR-based Mueller matrix polarimeter is designed on the basis of the Stokes polarimeter. The designed polarimeter combines the advantages of the high modulation frequency of FLCPR and the ultrahigh temporal resolution of the fast polarization measurement system in the Stokes polarimeter. The optimal configuration of the designed polarizer is predicted in accordance with singular value decomposition. A simulated thickness measurement of a 24 nm standard SiO2 thin film is performed using the optimal configuration. Results show that the relative error in thickness measurement caused by using the unsatisfactory modulation characteristics of FLCPR reaches up to −4.34%. This finding demonstrates the importance of the accurate characterization of FLCPR in developing a Mueller matrix polarizer.

Plant Phenotyping by Deep-Learning-Based Planner for Multi-Robots

Manual plant phenotyping is slow, error prone, and labor intensive. In this letter, we present an automated robotic system for fast, precise, and noninvasive measurements using a new deep-learning-based next-best view planning pipeline. Specifically, we first use a deep neural network to estimate a set of candidate voxels for the next scanning. Next, we cast rays from these voxels to determine the optimal viewpoints. We empirically evaluate our method in simulations and real-world robotic experiments with up to three robotic arms to demonstrate its efficiency and effectiveness. One advantage of our new pipeline is that it can be easily extended to a multi-robot system where multiple robots move simultaneously according to the planned motions. Our system significantly outperforms the single robot in flexibility and planning time. High-throughput phenotyping can be made practically.

Photonics-based dual-functional system for simultaneous high-resolution radar imaging and fast frequency measurement.

A photonics-based dual-functional system is proposed that can simultaneously implement high-resolution radar imaging and fast frequency measurement. In this system, the radar is realized based on photonic frequency doubling and de-chirp receiving, and the frequency measurement is achieved by a novel frequency-to-time mapping method. In the experimental demonstration, the radar works in Ku band with a bandwidth of 6GHz (12-18GHz), through which inverse synthetic aperture radar imaging with a resolution as high as ∼2.6 cm×∼2.8 cm is achieved. The frequency measurement module operates in Ka band, which can achieve a measurement frequency range from 28GHz to 37GHz, with a measurement resolution of 40MHz and a refresh rate of 100kHz.

IDENTIFICATION OF MAXIMUM INACCURACY OF TOOLMAKERS MICROSCOPE

Urgency of the research. There are several types of measurement devices. Industrial practice needs simple, fast and cheap measurement system for inspection of produced parts. There is a need for system like toolmakers microscope. Target setting. Toolmakers microscope is very popular because of its simplicity, but producer often do not provide information about the errors during the measurements. Actual scientific researches and issues analysis. Toolmakers microscope uses two methods of measurements – micrometer head slides in two axes XY and CCD camera for measurements of very small dimensions. Uninvestigated parts of general matters defining. The main problem is with expressing of uncertainty of measurements for both methods of measurements. There is no regulations and recommendation for using of both methods. The question of the probability distribution of measured values and number of minimum required measurements are uninvestigated, because the next research will be focused to this are. The research objective. The aim is to obtain maximum permissible error of explored toolmakers microscope. On the base of this the uncertainty of measurement could be expressed. Uncertainty measurement is non-separable parts of measurement results. The statement of basic materials. Gauge length blocks have been used for calibration of both measurement systems. Maximum permissible error has been estimated as math model for next using. Conclusions. The toolmakers microscope is suitable device for fast and cheap measurement right in industry condition. The producer did not provide information about the accuracy of measurement on this device. Calibration process can be used for estimation of this maximum error achieved during the measurement via using this device. Also this approach can be used for estimation of actual condition of measuring device.

Fast and precise 6D pose estimation of textureless objects using the point cloud and gray image.

Pose estimation for textureless objects is a challenging task in robotics, due to the scanty information of surfaces. In this paper, we design a vision system for fast and precise position and orientation measurement of textureless objects with a depth camera and a CCD camera. The corresponding process includes two parts: object segmentation in the point cloud and pose measurement in the gray image. Considering the relation between the object and its fixed panel, we first extract the panel in the point cloud by combining a random sample consensus algorithm with local surface normal. We then coarsely segment the possible area of the object based on an oriented bounding box. Finally, we transform the point cloud coordinates into the image coordinate system, and measure the precise pose of the object with a view-based matching method. Two types of cameras are brought together to make their respective advantages play well. The downscale method and coarse-to-fine strategy are utilized sufficiently to increase efficiency. Experiments show that our vision system achieves high pose measurement precision and enough efficiency. The average error is less than 2 mm for x and y, less than 4 mm for z, and 1° in orientation, meeting the requirements for our robotic grasping task.

Multipoint scanning dual-detection confocal microscopy for fast 3D volumetric measurement.

We propose a multipoint scanning dual-detection confocal microscopy (MS-DDCM) system for fast 3D volumetric measurements. Unlike conventional confocal microscopy, MS-DDCM can accomplish surface profiling without axial scanning. Also, to rapidly obtain 2D images, the MS-DDCM employs a multipoint scanning technique, with a digital micromirror device used to produce arrays of effective pinholes, which are then scanned. The MS-DDCM is composed of two CCDs: one collects the conjugate images and the other collects nonconjugate images. The ratio of the axial response curves, measured by the two detectors, provides a linear relationship between the height of the sample surface and the ratio of the intensity signals. Furthermore, the difference between the two images results in enhanced contrast. The normalising effect of the MS-DDCM provides accurate sample heights, even when the reflectance distribution of the surface varies. Experimental results confirmed that the MS-DDCM achieved high-speed surface profiling with improved image contrast capability.

Power Density Measurements at 15 GHz for RF EMF Compliance Assessments of 5G User Equipment

In this paper, different measurement schemes are studied in order to investigate the possibilities and limitations of scalar- and vector-based measurement systems for radio frequency electromagnetic fields compliance assessments of fifth generation mobile communication user equipment (UE). Two UE antenna array designs, transmitting at 15 GHz and employing patch and notch antenna elements, are considered for different phase excitations. Using free space power density as the exposure metric, the maximum permissible transmitted power of UE, compliant with the maximum permissible exposure limits specified by the U.S. Federal Communications Commission (FCC) and the basic restrictions of the International Commission on Non-Ionizing Radiation Protection, is determined. The accuracy of different measurement schemes is assessed using numerical simulation. Verifying measurements is carried out in a semianechoic chamber. The results indicate that, for UE employing array antennas and intended to be used in immediate vicinity of the human body, scalar measurement systems used in combination with straightforward field combination techniques will lead to overly conservative results. A more accurate and less conservative approach for these products is to conduct separate measurements for different excitations in order to span the space of possible excitations. This will result in a more complicated measurement setup and increase the measurement time, which points to a need for very fast measurement systems.