Measurement Technology Research Articles

Analysis of the Accuracy of CAD Modeling in Engineering and Medical Industries Based on Measurement Data Using Reverse Engineering Methods

The reverse engineering (RE) process is often necessary in today’s engineering and medical industries. Expertise in measurement technology, data processing, and CAD modeling is required to ensure accurate reconstruction of an object’s geometry. However, errors are generated at every stage of geometric reconstruction, affecting the dimensional and geometric accuracy of the final 3D-CAD model. In this article, the geometry of reconstructed models was measured using contact and optical methods. The measurement data representing 2D profiles, 3D point clouds, and 2D images acquired in the reconstruction process were saved to a stereolithography (STL) model. The reconstructed models were then subjected to a CAD modeling process, and the accuracy of the parametric modeling was evaluated by comparing the 3D-CAD model to the 3D-STL model. Based on the results, the model used for clamping and positioning parts to perform the machining process and the connecting rod provided the most accurate mapping errors. These models represented deviations within ±0.02 mm and ±0.05 mm. The accuracy of CAD modeling for the turbine blade model and the pelvis part was comparable, presenting deviations within ±0.1 mm. However, the helical gear and the femur models showed the highest deviations of about ±0.2 mm. The procedures presented in the article specify the methods and resolution of the measurement systems and suggest CAD modeling strategies to minimize reconstruction errors. These results can be used as a starting point for further tests to optimize CAD modeling procedures based on the obtained measurement data.

Logo recognition of vehicles based on deep convolutional generative adversarial networks

Vehicle logo recognition plays a critical role in enhancing the efficiency of intelligent transportation systems by enabling accurate vehicle identification and tracking. Despite advancements in image recognition technologies, accurately detecting and classifying vehicle logos in diverse and dynamically changing environments remains a significant challenge. This research introduces an innovative approach utilizing a Deep Convolutional Generative Adversarial Network (DCGAN) framework, tailored specifically for the complex task of vehicle logo recognition. Unlike traditional methods, which heavily rely on manual feature extraction and pre-defined image processing techniques, our method employs a novel DCGAN architecture. This architecture automatically learns the distinctive features of vehicle logos directly from data, enabling more robust and accurate recognition across various conditions. Furthermore, we propose a refined training strategy for both the generator and discriminator components of our DCGAN, optimized through extensive experimentation, to enhance the model’s ability to generate high-fidelity vehicle logo images for improved training efficacy. The technical core of our approach lies in the strategic integration of transfer learning techniques. These techniques significantly boost classification accuracy by leveraging pre-learned features from vast image datasets, thereby addressing the challenge of limited labeled data in the vehicle logo domain. Our experimental results demonstrate a substantial improvement in logo detection and classification accuracy, achieving an Intersection over Union (IoU) ratio of 42.67 % and a classification accuracy of 99.78 %, which markedly surpasses the performance of existing methods. This research not only advances the field of vehicle logo recognition but also contributes to the broader domain of measurement science and technology, offering a technically sound and logically coherent solution to a complex problem.

Measurement of Light Interception by Crops under Solar Panels using PARbars

To analyse agrivoltaics systems and understand crop responses to shading, measurements of available light for the crop and light interception by the crop are important. Especially in row crops, there is a lot of variation in the amount of light at different heights, different positions relative to the row and over time. This spatial and temporal variation in light is difficult to capture with standard point measurement technology. Commercially available line quantum sensors are not long enough to cover the desired width within an agrivoltaics system and come at high cost. Therefore, custom made PARbars were used: bars of 1.5 m long having light sensors every 5 cm facing the sky and giving a total (line) irradiance value per time step. PARbars were installed above and below a raspberry crop row in both the agrivoltaics system and the control with a plastic foil cover, and a point sensor was installed in the open field. The difference between open field radiation and the top PARbar gives the light interception by the panel construction or the foil cover, the difference between the top and bottom PARbar gives the light interception by the crop. This information can be used in conjunction with destructive crop measurements to analyse impacts on leaf area and light interception, dry matter production and derived efficiency of photosynthesis. The crop in the current agrivoltaics system received half of the amount of light compared to the control system, but total biomass production was less reduced because of compensation by increasing specific leaf area and photosynthesis efficiency. Further analysis is needed to evaluate the agrivoltaics system and the impact of increasing shade on the crop, and to assess the trade-off between electricity production and crop production.

Dual-Frequency, Ratiometric Approaches to EAB Sensor Interrogation Support the Calibration-Free Measurement of Specific Molecules In Vivo.

Electrochemical aptamer-based (EAB) sensors represent the first molecular measurement technology that is both (1) independent of the chemical reactivity of the target, and thus generalizable to many targets and (2) able to function in an accurate, drift-corrected manner in situ in the living body. Signaling in EAB sensors is generated when an electrode-bound aptamer binds to its target ligand, altering the rate of electron transfer from an attached redox reporter and producing an easily detectable change in peak current when the sensor is interrogated using square wave voltammetry. Due to differences in the microscopic surface area of the interrogating electrodes, the baseline peak currents obtained from EAB sensors, however, can be highly variable. To overcome this, we have historically performed single-point calibration using measurements performed in a single sample of known target concentration. Here, however, we explore approaches to EAB sensor operation that negate the need to perform even single-point calibration of individual sensors. These are a ratiometric approach employing the ratio of the peak currents observed at two distinct square wave frequencies, and a kinetic differential measurement approach that employs the difference between peak currents seen at the two frequencies. Using in vivo measurements of vancomycin and phenylalanine as our test bed, we compared the output of these methods with that of the same sensor when single-point calibration was employed. Doing so we find that both methods support accurately drift-corrected measurements in vivo in live rats, even when employing rather crudely handmade devices. By removing the need to calibrate each individual sensor in a sample of known target concentration, these interrogation methods should significantly simplify the use of EAB sensors for in vivo applications.

Efficient and robust 3D reconstruction: Absolute phase extraction algorithm based on three gray images

The structured light three-dimensional (3D) measurement technology based on optical metrics has gained increasing applications, and there is a growing demand for capturing transient trajectory changes in dynamic scenes. Conventional temporal phase unwrapping (TPU) approaches often require multi-frequency fringe patterns for application. However, the inevitable conflict arises between the number of projected fringe patterns and the measurement speed. This paper proposes a highly accurate and robust 3D measurement method using only 3-step phase-shifting fringe patterns. To precisely reconstruct the 3D shape using the fewest fringe patterns, it is essential to extract as much information as possible from the available patterns. Therefore, we calculate the wrapped phase distribution using 3-step phase-shifting fringe patterns to ensure accuracy. Simultaneously, the trapezoidal phase-shifting method is employed to calculate the intensity ratio distribution. Through the proposed region-based indexing method, the intensity ratio map is transformed into an unwrapped phase map. Additionally, a novel self-correction method is introduced to correct the non-linear errors in the unwrapped phase map, which is then utilized for the calculation of the fringe order required for phase unwrapping. This high-speed measurement method utilizes only 3-step phase-shifting fringe patterns while retaining the advantages of TPU, meeting the requirements of high-speed and full-field measurements. Experimental results on both static and dynamic scenes validate the effectiveness and versatility of the proposed method, demonstrating its flexibility and simplicity in application. In our 3D measurement system, the method achieves 3D reconstruction of the dynamic object's trajectory at a measurement speed of 107 frames per second.

Enhancing solid-liquid separation performance of copper tailings by regulating settling floc properties

The effective improvement of dewatering performance of fine tailings slurry is a common challenge in tailings disposal and mining environmental protection worldwide. Flocculation is a commonly used method for solid-liquid separation of tailings, and the properties and structure of tailings flocs play a key role in sedimentation and filtration performance. This study proposed to improve the dewatering efficiency of tailings by regulating the floc properties and structure through polycarboxylate ether/ester (PCE). It simultaneously enhanced dewatering speed and reduced filter cake moisture. Dewatering experiments results showed that the assistance of PCE increased the initial filtration rate (IFR) of tailings by approximately 60 % and reduced filter cake moisture by 4.16 %. Moreover, the increase of shear strength in the slurry had a detrimental effect on dewatering performance. The dynamic evolution process of flocs was studied using focused beam reflectance measurement (FBRM) technology. The results showed that the addition of PCE caused a significant increase in floc size and counts, while the structural strength and regrowth ability of flocs also improved. Floc density calculations and scanning electron microscope (SEM) observations revealed that PCE caused densification of flocs, with particles aggregating more compactly. Contact angle analysis indicated that the adsorption of PCE on particles surface weakened their hydrophilicity. This study could conduce to understand the mechanism of dewatering performance enhancement in solid-liquid separation.

Development of a Measurement Device for Micro Gas Flowrate Based on Laminar Flow Element with Micro-Curved Surface

The laminar flow meter (LFM) boasts several advantages such as no moving parts, a wide range ratio, high measurement accuracy, quick dynamic response, etc., and is a promising technology for micro gas flow measurement. In order to explore the influence of different curvature radii on curved surface gap LFM, three curved structures with different curvature radii were designed. The computational fluid dynamics method is applied to simulate the flow feature of three structures. The simulated velocity cloud and pressure distribution show that the larger the curvature radius, the more stable the flow of gas medium. The relationship between differential pressure and volume flow was obtained through the test within a flow range of 0~540 sccm. Regression analysis revealed that the volume flow measured by the curved surface LFM had a high linear relationship with the differential pressure. Experimental findings indicate that differential pressure of the structure with a curvature radius of 2 mm was greater than that of other two structures (curvature radius of 6 mm and 3 mm) at the same point. This indicates that adding the number of surfaces can effectively increase the pressure loss, so as to obtain a larger range ratio, but will increase the measurement error.

Determining the optimal diagnostic and risk stratification approaches for people with hypertension in two rural populations in Kenya and The Gambia: a study protocol for IHCoR-Africa Work Package 2.

Sub-Saharan Africa (SSA) has one of the highest prevalences of hypertension worldwide. The impact of hypertension is of particular concern in rural SSA, where access to clinics and hospitals is limited. Improvements in the management of people with hypertension in rural SSA could be achieved by sharing diagnosis and care tasks between the clinic and the community. To develop such a community-centred programme we need optimal approaches to identify and risk stratify patients with elevated blood pressure. The aim of the study is to improve the evidence base for diagnosis and risk estimation for a community-centred hypertension programme in two rural settings in SSA. We will conduct a cross-sectional study of 1250 adult participants in Kilifi, Kenya and Kiang West, The Gambia. The study has five objectives which will determine the: (1) accuracy of three blood pressure (BP) measurement methods performed by community health workers in identifying people with hypertension in rural SSA, compared to the reference standard method; (2) relationship between systolic BP and cardiovascular risk factors; (3) prevalence of hypertension-mediated organ damage (HMOD); (4) accuracy of innovative point-of-care (POC) technologies to identify patients with HMOD; and (5) cost-effectiveness of different combinations of BP and HMOD measurements for directing hypertension treatment initiation. This study will determine the accuracy of three methods for community BP measurement and POC technologies for HMOD assessment. Using the optimal methods in this setting it will estimate the prevalence of hypertension and provide the best estimate to date of HMOD prevalence in SSA populations. The cost-effectiveness of decision-making approaches for initiating treatment of hypertension will be modelled. These results will inform the development of a community-centred programme to improve care for hypertensive patients living in rural SSA. Existing community engagement networks will be used to disseminated within the research setting.

Developing a ‘fit for purpose’ approach to measuring methane emissions

Tackling methane emissions from fossil fuel operations represents one of the best near- and medium-term opportunities for limiting the effects of climate change. Over the last few years, independent methane studies have challenged the accuracy and completeness of publicly disclosed emissions estimates. To address this, new methane accounting and reporting frameworks have been developed. Central to these frameworks are key principles linked to measurement, monitoring, reporting, verification (MMRV) and reduction. Woodside has taken specific actions to measure and reduce its methane emissions and is developing a pathway to embed ongoing and sustainable measurements technologies in its operations. Previously, Woodside discussed the management and valuation of methane reductions, this paper will describe the approach taken to develop methane measurement plans including (i) the objective of measurement plans, (ii) measurement technology attributes and (iii) the identification of measurement technology use cases. It also overviews measurement techniques such as satellite, aerial, drone, handheld and continuous monitoring which can form part of a curated multi-scale approach to MMRV across a portfolio of assets.

A Combined Filtering Method for ZigBee Indoor Distance Measurement.

Indoor distance measurement technology utilizing Zigbee's Received Signal Strength Indication (RSSI) offers cost-effective and energy-efficient advantages, making it widely adopted for indoor distance measurement applications. However, challenges such as multipath effects, signal attenuation, and signal blockage often degrade the accuracy of distance measurements. Addressing these issues, this study proposes a combined filtering approach integrating Kalman filtering, Dixon's Q-test, Gaussian filtering, and mean filtering. Initially, the method evaluates Zigbee's transmission power, channel, and other parameters, analyzing their impact on RSSI values. Subsequently, it fits a signal propagation loss model based on actual measured data to understand the filtering algorithm's effect on distance measurement error. Experimental results demonstrate that the proposed method effectively improves the conversion relationship between RSSI and distance. The average distance measurement error, approximately 0.46 m, substantially outperforms errors derived from raw RSSI data. Consequently, this method offers enhanced distance measurement accuracy, making it particularly suitable for indoor positioning applications.

Comparation between Fibroscan and Hepatus for detecting NAFLD in patients with metabolic dysregulation

Background The clinical application of the innovative instantaneous elasticity and fat attenuation measurement technology, Hepatus, is currently in the evaluation stage. This study aimed to compare the detection performance of Fibroscan and Hepatus in patients with metabolic dysregulation who are "at-risk" for non-alcoholic fatty liver disease (NAFLD).Methods Between January 2021 and April 2021, 149 patients were enrolled in this study. Clinical data were collected, and all patients underwent both Fibroscan and Hepatus assessments to determine liver stiffness measurement (LSM) and attenuation parameters. The correlation between the results obtained from the two transient elastography (TE) devices was analyzed. Receiver operating characteristic curves (ROC) were constructed to compare the diagnostic value of Fibroscan and Hepatus for Hepatic Steatosis Index (HSI)-based NAFLD.Results The detection success rate of Hepatus (100.0%) was higher than that of Fibroscan (96.0%). LSM (r = 0.663, P0.05) and attenuation parameters (r = 0.778, P0.05) obtained by Fibroscan and Hepatus were significantly correlated. Hepatus tended to produce a higher LSM (Hepatus vs. Fibroscan: 6.04 vs. 5.66 kPa, P=0.016) but a lower attenuation parameter than Fibroscan (Hepatus vs. Fibroscan: 264 vs. 277 dB/m, P0.001). The area under the ROC curve for detecting HSI-based NAFLD was 0.811 for Fibroscan and 0.832 for Hepatus.Conclusion Measurements obtained by Fibroscan and Hepatus are strongly correlated, and the diagnostic value of the two TE devices is comparable in detecting HSI-based NAFLD. Hepatus offer a potential TE alternative in NAFLD examination.

Capillary Point Discharge-Optical Emission Spectrometer: field portable mercury analyzer

Environmental mercury pollution poses a serious threat to public health and ecosystems, underscoring the value of rapid and accurate on-site mercury measurement technologies. Therefore, a portable mercury analyzer was developed with capillary point discharge for excitation and cold vapor generation for sample introduction. A limit of detection (LOD) of 0.23 μg L−1 for mercury was achieved, relative standard deviations below 5 % were maintained in a 10-hour testing period. This method was successfully used for mercury determination of spiked water samples, fish meat, and laboratory wastewater. Powered by several power banks, it can be used to monitor mercury levels in water samples continuously over a working day. Compared with traditional technology, this one greatly reduces the size of the instrument, the consumption of working gas, and the construction cost, making it suitable for rapid field analysis of many types of samples for trace mercury.

Evaluation of the Influence of Water Content in Oil on the Metrological Performance of Oil Flow Measurement Systems

According to current Brazilian regulations, if the volumes of oil produced used as a reference for the payment of government shares and third parties contain a water content greater than 2% v/v, these volumes must be arbitrarily increased between 1.44% and 10.89% due exclusively to water content, which has caused operational problems for oil companies such as differences between volumes produced and volumes sold, and additional payments from government shares and third parties. This study aimed to evaluate the metrological performance of oil measurement systems with ultrasonic, Coriolis and positive displacement flow meters when subjected to varied water content, fluid temperature and flow rate conditions using the Design of Experiments and the Response Surface Methodology. The analysis of variance showed that the models presented good fits for the ultrasonic meter (coefficient of determination R2 of 97.96%, p-value of 0.001, and a standard deviation of 5.89 × 10−5); Coriolis meter (R2 of 90.91%, p-value of 0.037, and a standard deviation of 5.88 × 10−5); and positive displacement meter (R2 of 99.07%, p-value of 0.000, and a standard deviation of 4.85 × 10−5). The results of the experiments carried out indicate that the contribution of each parameter analyzed to the metrological performance of the measurement system varies depending on the measurement technology used by the flow meter. However, the fluid temperature proved to be a relevant parameter common to all flow measurement technologies evaluated. All measuring technologies evaluated were influenced by water content in the range of 0% to 10% v/v, with the measurement error being less than 0.2% when compared to a standard positive displacement type meter in almost all experimental conditions. The Coriolis-type flow meter was the one that presented the smallest error among the measuring technologies evaluated.

Dielectrophoresis: Measurement technologies and auxiliary sensing applications.

Dielectrophoresis (DEP), which arises from the interaction between dielectric particles and an aqueous solution in a nonuniform electric field, contributes to the manipulation of nano and microparticles in many fields, including colloid physics, analytical chemistry, molecular biology, clinical medicine, and pharmaceutics. The measurement of the DEP force could provide a more complete solution for verifying current classical DEP theories. This review reports various imaging, fluidic, optical, and mechanical approaches for measuring the DEP forces at different amplitudes and frequencies. The integration of DEP technology into sensors enables fast response, high sensitivity, precise discrimination, and label-free detection of proteins, bacteria, colloidal particles, and cells. Therefore, this review provides an in-depth overview of DEP-based fabrication and measurements. Depending on the measurement requirements, DEP manipulation can be classified into assistance and integration approaches to improve sensor performance. To this end, an overview is dedicated to developing the concept of trapping-on-sensing, improving its structure and performance, and realizing fully DEP-assisted lab-on-a-chip systems.

Innovative engine test bench set-up for testing of exhaust gas aftertreatment and detailed gas species analysis for CNG-SI-operation

For an efficient reduction of methane slip, a precise understanding of exhaust gas after treatment under real conditions is essential. Since it is not possible to produce catalytic converters in near-series geometry on a laboratory scale, it is necessary to resort to significantly smaller sample catalysts. Therefore, an engine test bench was designed to ensure real operating conditions for such samples with the help of space velocity and temperature control. A comparison between the actual and reference values of the space velocity results in a small deviation of 0.1% on average. Furthermore, the pressure conditions at the catalyst have been measured showing a propagation of pressure oscillations from the engine outlet which in combination with the space velocity regulation show that real conditions could be applied to the catalyst sample. Subsequently, the exhaust gas concentrations were monitored with a Fourier transform infrared spectrometer. The catalyst material used is PdO on Al2O3, common for methane oxidation. The measurements show that the CH4 conversion is higher under lean conditions, but is below complete conversion. In a final comparison between purely stoichiometric operation and dithering, the course of the CH4 conversion rate over the test period is examined more closely. In addition to sampling pre- and post-catalyst, the exhaust gas composition is measured spatially resolved within a catalyst channel using special measurement technology. In the temporal course of the CH4 emissions, a stabilizing effect due to the change of the operating mode can be seen, showing that dithering seems to prevent further deactivation.

Science in the service of politics. The cartographic representation of a local territorial context of the Kingdom of Naples in the early nineteenth century

The erudite priest Marciano Di Leo (1751–1819), a prominent personality in the historical and geographical panorama of his time, not only in his home territory, authored a vast literary and poetic production, but also tried his hand at producing some maps, referring to a province of the Kingdom of Naples. At a time when the principles of geodetic cartography had become increasingly known, even locally, hand in hand with improvements in technology and accuracy of measurements, the author reflects the historical narratives of progress of the European (and Neapolitan) Enlightenment and translates them into an unpublished manuscript of statistical, historical, and geographical nature, accompanied by numerous maps of various scales. The rediscovery of a largely unknown—and therefore not very thorough—minor cartographic production underscores the spread even in more marginal contexts of the most innovative ideas and increasingly precise scientific foundations in the cartographic-mathematical representation of the territory. It also illustrates the role of a number of intellectuals in the service of the political choices of their time, in an attempt-often unrealized-to bring about a decisive change of course in public administration, in accordance with Enlightenment ideals and in the spirit of reform that spread throughout Europe thanks to the French Revolution.

A novel methodology to assess optical profilometer stability to discriminate surface roughness

A new method is proposed to investigate the measurement variation of instruments and their ability to discriminate two TA6V surfaces obtained by grinding with SiC grit papers (80 and 120). Three optical measurement technologies included into a single apparatus, namely Confocal Microscopy (CM), Focus Variation (FV) and Coherence Scanning Interferometry (CSI), were used to measure both ground surfaces according to a specific experimental protocol (MorphoMeca Monitoring) based on measurement iterations and repetitions. From the measurements, four indices were built from the Sa roughness parameter to assess the Quality (ratio of the topographical variability over the measurement noise), the Drift (related to surface fluctuations) and the Stability (estimation of the temporal drift using a second order autoregressive model) of the three measurement technologies (modes), as well as their Relevance (computed from an analysis of variance) to discriminate ground surfaces with close roughness. For these investigated surfaces, it was especially highlighted that the Quality Index is four times higher for the CSI mode than for the FV and CM modes. All the used measurement modes experienced small drifting (Drift Index) during the measurements. The CSI mode was slightly more sensitive to drift than the FV and CM modes. The Stability Index indicated that there was no memory effect between two acquisitions for each measurement mode, i.e., the temporal drift did not depend on the measurement mode. Moreover, the three measurement modes are able to discriminate the two ground surfaces with the same accuracy through the Sa parameter. However, the Sa values may vary depending on the measurement modes, and it was finally shown that the Sa parameter is minimized by 0.03 μm for the FV mode compared with the CSI mode, due to its smoothing effect.

Research on water level measurement technology based on the residual length ratio of image characters

Research on water level measurement technology based on the residual length ratio of image characters

Partially “invisible” pulsation of asymmetric soliton molecules

Pulsation is a universal phenomenon in all disciplines of nonlinear science, which generally exhibit various nonlinear soliton dynamic modes in nonlinear optics. With the emergence of real-time spectral measurement technology, a new phenomenon of optical soliton pulsation, “invisible” soliton pulsation, has gradually attracted researchers’ attention. In this paper, by solving the coupled Ginzburg–Landau equation, we have discovered the partially “invisible” pulsation phenomenon of asymmetric soliton molecules (SMs) composed of two unequal-intensity pulses in a normal-dispersion Mamyshev oscillator for the first time. It is indicated that the fluctuation periods of each internal pulse in asymmetric SMs in terms of peak power, energy, and relative phase difference are all four roundtrips. However, the oscillation period of asymmetric SMs energy is two roundtrips, only half of the above period. Further research shows that the oscillation of the relative phase difference between two internal pulses in SMs is related to the variation of their intensity difference, which can also affect the position change of the spectral modulation peak. This work will enrich the research on “invisible” soliton pulsation and is of great significance for promoting the development of nonlinear dissipative systems.

AHFO-based soil water content sensing technology considering soil–sensor thermal contact resistance

The actively heated fiber-optic (AHFO) technology has become emerged as a research focus due to its advantages of distributed, real-time measurement and good durability. These attributes have led to the gradual application of AHFO technology to the water content measurement of in situ soil. However, all existing in situ applications of AHFO technology fail to consider the effect of soil–sensor contact quality on water content measurements, limiting potential for the wider application of AHFO technology. To address this issue, the authors propose a method for determining the soil–sensor thermal contact resistance based on the principle of an infinite cylindrical heat source. This is then used to establish an AHFO water content measurement technology that considers the thermal contact resistance. The reliability and validity of the new measurement technology are explored through a laboratory test and a field case study, and the spatial-temporal evolution of the soil water content in the case is revealed. The results demonstrate that method for determining the soil–sensor thermal contact resistance is highly effective and applicable to all types of soils. This method requires only the moisture content, dry density, and thermal response of the in situ soil to be obtained. In the field case, the measurement error of soil water content between the AHFO method, which takes into account the thermal contact resistance, and the neutron scattering method is only 0.011. The water content of in situ soil exhibits a seasonal variation, with an increase in spring and autumn and a decrease in summer and winter. Furthermore, the response of shallow soils to precipitation and evaporation is significant. These findings contribute to the enhancement of the accuracy of the AHFO technology in the measurement of the water content of in situ soils, thereby facilitating the dissemination and utilization of this technology.