Short Measurement Time Research Articles

Electrochemical Reactions Affected by Electric Double Layer Overlap in Conducting Nanopores.

When a potential is applied to an electrode immersed in an electrolyte solution, ions with opposite charges accumulate around the electrode, forming an electrical double layer (EDL). Unlike flat electrodes, nanoporous electrodes with pore sizes comparable to the EDL thickness experience overlapping EDLs, altering the electrochemically effective surface area. Although previous research has primarily examined the ion charging dynamics and EDL formation in nanoporous electrodes, the impact of EDL overlap on Faraday reactions remains underexplored. In this study, we examined the influence of EDL overlap on electrochemical reactions within nanoporous electrodes using chronoamperometry and DC and AC voltammetry. We used the electrolyte concentration, measurement duration, overpotential, and electrode material as variables to determine the relationship between the extent of EDL overlap and the electrochemical reaction. The electrolyte concentration-dependent electrochemical reaction due to the EDL overlap was more pronounced for electrodes with faster potential changes, shorter measurement times, lower overpotentials, and slower catalytic activity. This is a unique nanoporous electrochemical phenomenon that is not observed on flat electrodes. These findings provide insight into the utilization of nanoporous electrodes in catalytic and sensor applications.

Automatic Algorithm Applied for Calculating Thermal Conductivity by Transient Plane Source Method

As a thermal conductivity measurement method, Transient Plane Source (TPS) method has gained much popularity because of its broad applicability, short measurement times, high precision and simple sample preparation. However, the accuracy of thermal conductivity calculations based on temperature rise data is often hindered by factors such as probe thickness, contact thermal resistance, and input power. Currently, there is no standardized criteria for selecting effective temperature rise data for thermal conductivity calculation. Consequently, the accuracy of results are limited by the operator's understanding of the TPS methods, and repeatability of the results is often poor. To address this issue, an automatic algorithm based on the international standard (ISO22007-2:2008) is proposed in this paper. By applying this algorithm to the measurement of different materials, it has been demonstrated that the proposed algorithm can produce more precise and consistent results than the conventional method. Additionally, the integration of the time window function , typically utilized solely for result validation in conventional methods, further enhances the objectivity and reproducibility of the results obtained by the automatic algorithm.

The Effect of Surface Preparation on Result Deviations During Roughness Measurements Using the Contact Method

This paper presents the influence of the preparation of the inspected surface on the deviations obtained when measuring the basic roughness parameters using the contact method. The problems described in the article are often encountered in industry when measurements are performed in mass production conditions, where a short measurement time is extremely important. Presented are the measurement results of five samples made of 1.0503 steel after the grinding process, subjected to various methods of preparation for roughness measurement: sample immediately after treatment, sample after treatment and after evaporation of liquid part of the coolant, sample after blowing with compressed air, sample after blowing with compressed air and washing in isopropyl alcohol, and the sample after blowing with compressed air and washing with acetone. The measurement results obtained from the contact profilometer provide the basis for developing recommendations regarding the preparation of surfaces for inter-operational and final measurements in the production process.

Revealing Spatial Molecular Heterogeneity of High-Density Biofunctionalized Surfaces Using DNA-PAINT.

The quantification and control of molecular densities and distributions on biofunctionalized surfaces are key for enabling reproducible functions in biosciences. Here, we describe an analysis methodology for quantifying the density and spatial distribution of high-density biofunctionalized surfaces, with densities in the order of 102-105 biomolecules per μm2 area, in a short measurement time. The methodology is based on single-molecule DNA-PAINT imaging combined with simulation models that compensate for lifetime and spatial undersampling effects, resulting in three distinct molecule counting methods and a statistical test for spatial distribution. The analysis methodology is exemplified for a surface with ssDNA affinity binder molecules coupled to a PLL-g-PEG antifouling coating. The results provide insights into the biofunctionalization efficiency, yield, and homogeneity. Furthermore, the data reveal that heterogeneity is inherent to the biofunctionalization process and shed light on the underlying molecular mechanisms. We envision that DNA-PAINT imaging with the developed analysis framework will become a versatile tool to study spatial heterogeneity of densely biofunctionalized surfaces for a wide range of applications.

Influence of the Traverse Speed of the Stylus Tip on Changes in the Areal Texture Parameters of Machined Surfaces

Measurements of areal (3D) surface texture using optical methods are very popular because of the short measurement time compared to the stylus tip technique. However, they are very sensitive to measurement errors. In some cases, optical measurements are not recommended. The stylus measurement method is well known and can be the reference technique for surface texture measurement. The main disadvantage is the long measuring time. This time can be shortened using higher speeds of measurement. The effect of the speed of the measurement of stylus profilometer on changes in surface texture parameters was studied. Fifty surface topographies were measured using the stylus profilometer at speeds 0.5, 1, 2, 3, 4, and 5 mm/s in the same places. Surfaces after lapping, polishing, grinding, milling, laser texturing, and two-process random surfaces were measured and analyzed. Changes in parameters caused by the increase in the traverse speed depend on the characteristics and parameters of the surfaces. The random surfaces changed more than the deterministic ones. The increase in the traverse speed from 0.5 to 1 mm/s caused small changes in the parameters.

Building noise maps in Uruguay: a practical methodology

Uruguay is a small country in Latin America, with around 3400000 inhabitants. Its environmental legislation is still incomplete; for example, there is no national regulation on noise but only departmental Ordinances in each of its 19 Departments. Although it is well-known that they are very good management tools, noise maps are not mandatory in Uruguay. The Research Group on Environmental Noise at Universidad de la República has developed a research project that seeks the best practical methodology to build noise maps through manual measurements. The field work included the determination of the stabilization time of noise measurements, the comparison between long- and short-time measurements, the comparison between measurements taken at 1,20 m and 3,50 m, and the obtention of a national curve of highly annoyed people (%HA) with basis in the field measurements and simultaneous survey carried out on site. In this paper we present the results of these works and the proposed methodology for building noise maps throughout the country.

20 µm resolution multipixel ghost imaging with high-energy x-rays

Hard x-ray imaging is indispensable across diverse fields owing to its high penetrability. However, the resolution of traditional x-ray imaging modalities, such as computed tomography (CT) systems, is constrained by factors including beam properties, the limitations of optical components, and detection resolution. As a result, the typical resolution in commercial imaging systems that provide full-field imaging is limited to a few hundred microns, and scanning CT systems are too slow for many applications. This study advances high-photon-energy imaging by extending the concept of computational ghost imaging to multipixel ghost imaging with x-rays. We demonstrate a remarkable resolution of approximately 20 µm for an image spanning 0.9 by 1 cm2, comprised of 400,000 pixels and involving only 1000 realizations. Furthermore, we present a high-resolution CT reconstruction using our method, revealing enhanced visibility and resolution. Our achievement is facilitated by an innovative x-ray lithography technique and the computed tiling of images captured by each detector pixel. Importantly, this method maintains reasonable timeframes and can be scaled up for larger images without sacrificing the short measurement time, thereby opening intriguing possibilities for noninvasive high-resolution imaging of small features that are invisible with the present modalities.

Real-time detection of cerebral edema in mice based on low-field nuclear magnetic resonance

Cerebral edema is a secondary symptom of several conditions, including stroke, liver, failure, and severe craniocerebral injury. This study aimed to propose a Low-Field Nuclear Magnetic Resonance (LF-NMR) method for rapid and nondestructive measurement of brain water content and water phase state evaluating animal brain edema models. The water transverse relaxation time (T2) distribution in brain tissues was ascertained by measuring the T2 spectrograms of mouse brain tissues following various drying durations, in accordance with the shifting law of T2 peaks. A methodological study was carried out for the determination of water content in mouse brain tissue by the LF-NMR Peak Area (LF-NMR-PA) method using CuSO4 solution as standard solution. This method was studied in comparison with the wet/dry weight method and the Partial Least Squares Regression (PLSR) prediction method in normal and MCAO model mice, and further applied to the study of mannitol treatment of cerebral edema to validate the precision and accuracy of the hydration measurements as well as the method’s impact on subsequent experiments of cerebral infarct area measurement. In the T2 spectra of mouse brain tissues, the separate peaks T21 (0–10 ms), T22 (10–100 ms), and T23 (100–1000 ms) correspond to fat and bound water, water, and free water in brain tissue, respectively. The LF-NMR-PA method had good specificity, linearity, precision, stability, reproducibility, and recovery. The accuracy and range of use of the LF-NMR-PA method were better than those of the PLSR method, and its results were not significantly different from those of the wet/dry weight method. However, the short measurement time of the LF-NMR-PA method ensured the integrity of the tissues, and the determination of the moisture by this method did not have a significant effect on the subsequent determination of the area of cerebral infarction, which ensured the consistency of the experimental results.

Adding Rare Earth Oxide Markers to Polyoxymethylene to Improve Plastic Recycling through Tracer-Based Sorting.

Engineering plastics, such as polyoxymethylene (POM), are high-performance thermoplastics designed to withstand high temperature or mechanical stress and are used in electronic equipment, the automotive industry, construction, or specific household utensils. POM is immiscible with other plastics but due to a low volume of production, no methods were developed to separate it from the residual plastic waste stream. Therefore, POM recycling is minimal despite its high market value. This paper provides a proof of concept for tracer-based sorting (TBS) as a potential solution for increasing the separation efficiency of low-volume, high-quality polymers. For this purpose, yttrium oxide (Y2O3) and cerium (IV) oxide (CeO2) have been embedded into the POM matrix. Mechanical tests of samples at varying concentrations (0.1 to 1000 ppm) of both tracers were conducted, followed by an analysis of detectability and dispersibility using a portable X-ray fluorescence spectrometer (p-XRF), subsequently optimizing detection time and tracer concentration. Finally, an experimental scenario was developed to test the fate and potential recovery of the tracer material after the thermal treatment of plastics. A low detectable concentration, short measurement time, low influence on mechanical parameters of the compound, and low loss ratio after simulated recycling prove Y2O3 to be a suitable tracer for the industrial implementation of TBS.

Rapid, non-contact identification of organic solvents: Monolithic GaN chips incorporating PDMS/PS photonic crystals

The prompt identification of organic solvents is essential in many practical scenarios. This work introduces a compact optical device for rapid, non-contact detection of organic solvents. The fabrication of the GaN chip employs a monolithic integration approach, enabling the simultaneous formation of on-chip components responsible for light emission and light detection. The self-assembled polystyrene (PS) spheres embedded in a polydimethylsiloxane (PDMS) layer as photonic crystals can effectively induce distinct optical changes when exposed to organic solvents. By analyzing the magnitude and recovery time of the photocurrent signals, up to seven types of organic samples can be distinguished. Different from traditional optical sensing systems, the proposed chip-level integration strategy eliminates the need for external assembly of optical components, resulting in an ultracompact millimeter-sized sensing unit. The developed device also offers features of simplicity of use and a short measurement time of less than 10 s, making it a feasible solution for quick detection in emergency scenarios.

GNSS location error reduction method for microtremor survey system based on EMD-CNN-LSTM

Abstract Large errors exist when the microtremor survey system uses the global navigation satellite system (GNSS) for static localization. Aiming at the problem that the existing methods cannot effectively weaken the random error and multipath error, an error weakening method based on Empirical Mode Decomposition (EMD), Convolutional Neural Networks (CNN), and Long Short-term Memory Networks (LSTM) is proposed. The model first uses EMD to decompose the high-frequency random error, then reconstructs the low-frequency component and extracts the local features using CNN, and finally learns the change rule of multipath error using LSTM and weakens it. The model can remove random errors in the early stage while reducing the interference of noise on the neural network in the later stage and then improve the accuracy of localization. The experimental results show that the model can effectively improve the localization accuracy in the case of short-time measurements so that the localization accuracy in the E, N, and U directions can be improved by 74.57%, 74.76%, and 71.86%, respectively, which is more than 10% higher than the localization accuracy improvement rate of the existing CNN-LSTM model.

Bayesian peak identification method for low count rate gamma spectrum under short-time measurement based on physical priors

A Bayesian peak identification method based on physical model had been proposed in this study to perform qualitative analysis for the low count rate gamma spectrum under short-time measurement. Based on the prior knowledge about gamma detection, the distribution of energy deposited in the detector near the region of interest of a target peak through photoelectric effect, Compton scattering and multiple scattering had been analyzed and approximated using three elementary components, then, the distribution of each component after convolution had been studied, and at last, a probabilistic mixture model had been proposed to directly describe the distribution of measured energy within region of interest. When the data measurement has been completed, a Gibbs sampler was used to estimate the posterior distribution of model parameters to discriminate the existence of target peaks. The numerical and physical experiments were performed to verify the effectiveness of the parameter estimation algorithm and the performance of the proposed identification method. The numerical experiments showed the identification precision is proportional to counts and peak-to-total ratio, when the peak-to-total ratio is greater than 0.5, the proposed method could identify the peak with a probability greater than 50% given 50 observations. The physical experiment used a NaI(Tl) detector to measure 137Cs, 60Co and 152Eu sources in a laboratory environment at different equivalent distances, the peak identification precision had been tested for the proposed method, and the experiments proved that the probabilistic model is a good approximation to the physical process, and the proposed identification method outperformed the conventional method under short-time measurement conditions.

Quantification of API content in pharmaceutical tablets within milliseconds by time-stretch near-infrared transmission spectroscopy

We explored the feasibility of high-speed and high-accuracy quantification of active pharmaceutical ingredient (API) content in tablet products by near-infrared (NIR) spectroscopy to improve the reliability of pharmaceuticals. For this purpose, we employed a high-power NIR time-stretch transmission spectrometer recently developed by us. By using this transmission spectrometer with a multivariate calibration model, we demonstrated the ability to quantify API content with a short measurement time of 3.9 ms per tablet for model pharmaceuticals. For the model tablet, the quantification ability of our spectrometer was comparable to that achieved by a commonly used Fourier-transform NIR (FT-NIR) spectrometer with a measurement time of several seconds. We also confirmed that the effect of irradiating tablets with the NIR pulses used in our spectrometer was negligible.

High Power Pulsed LED Driver for Vibration Measurements.

Vibration measurements pose specific experimental challenges to be faced. In particular, optical methods can be used to obtain full-field vibration information. In this scenario, stereo-camera systems can be developed to obtain 3D displacement measurements. As vibration frequency increases, the common approach is to reduce camera exposure time to avoid blurred images, which can lead to under-exposed images and data loss, as well as issues with the synchronization of the stereo pair. Both of these problems can be solved by using high-intensity light pulses, which can produce high-quality images and guarantee camera synchronization since data is saved by both cameras only during the short-time light pulse. To this extent, high-power Light-Emitting Diodes (LEDs) can be used, but even if the LED itself can have a fast response time, specific electronic drivers are needed to ensure the desired timing of the light pulse. In this paper, a circuit is specifically designed to achieve high-intensity short-time light pulses in the range of 1 µs. A prototype of the designed board was assembled and tested to check its capability to respect the specification. Three different measurement methods are proposed and validated to achieve short-time light pulse measurements: shunt voltage measurement, direct photodiode measurement with a low-cost sensor, and indirect pulse measurement through a low-frame-rate digital camera.

Efficiency and feasibility of semi-automated software for measuring left atrial volume in routine echocardiography in a pediatric population.

The traditional method for measuring left atrial volume (LAV) involves manual tracing. Recently, semi-automated techniques for measuring LAV, based on 2D speckle tracking echocardiography (STE) and 3D echocardiography (3DE), have become commercially available. This study aimed to investigate the efficiency and feasibility of these semi-automated software methods for LAV measurement in pediatric patients. We analyzed 207 pediatric patients with 2D and 3D echocardiographic images of the left atrium. The maximum LAV was measured using three techniques: (1) manual tracing, (2) STE-based semi-automated measurement, and (3) 3DE-based semi-automated measurement. We compared both LAV and the time required for LAV measurement among these three techniques. Intra- and inter-observer reproducibility of the LAV measurements was assessed using the intraclass correlation (ICC). There was no difference in the LAV between the manual tracing and the STE-based method, but the LAV measured by 3DE-based method was slightly smaller than manual tracing. The measurement time was 32.6 ± 3.5, 53.8 ± 10.8, and 33.8 ± 13.0s for manual tracing, STE-based, and 3DE-based techniques, respectively. There was no difference the time for LAV measurement between the manual tracing and the 3D-based technique. The agreement and ICC for intra-observer reproducibility was similar across all three techniques, but inter-observer reproducibility was superior with the 3DE-based technique. Although the maximum LAV obtained through the 3DE-based techniques was slightly smaller compared with the traditional manual tracing method, the 3DE-based technique is anticipated to be integrated into routine examinations owing to its short measurement time and superior reproducibility.

Frequency shift of parametric sound by face-to-face pair of sources in relative motion.

This paper reports an acoustic phenomenon regarding a parametric sound source (also referred to as a parametric array): a secondary sound wave is generated from the nonlinear interaction of multiple primary sound waves with varied frequency components, particularly when two relatively moving sound sources face each other. It was found that the frequency of the secondary wave fluctuated according to the source movement and provided a theoretical explanation for this phenomenon. It is experimentally demonstrated that this frequency shift was approximately proportional to the velocity of the moving source toward the fixed source and to the driving frequency of the moving source. This phenomenon has much in common with the Doppler's effect, but its unique property is that the frequency shift depends on neither the observation position nor the source velocity toward the observer. These sound generation principles enable measurement of the velocity of slowly moving sound sources while maintaining a low-modulation frequency band and a short measurement time. This phenomenon can potentially be applied to an alternative approach for acoustic noncontact velocimetry of moving objects.

A Multifunctional Online Estimation Method for Synchronous Inertia of Power Systems Using Short-Time Phasor Transient Measurement Data With Linear Least Square Method After Disturbance

A Multifunctional Online Estimation Method for Synchronous Inertia of Power Systems Using Short-Time Phasor Transient Measurement Data With Linear Least Square Method After Disturbance

Ultraviolet-Visible Absorption Spectroscopy of MoCl5, MoOCl4, and MoO2Cl2 Vapors.

This article reports quantitative absorption spectra for MoCl5, MoOCl4, and MoO2Cl2 in the vapor phase from 45,500 to 15,500 cm-1 (645 to 220 nm). Spectra are obtained in an ultrahigh purity stainless steel vacuum system by rapidly sampling a range of analyte partial pressures. The short measurement times and the differential absorbance method employed here minimize effects from uncontrolled transients such as window deposits. A detailed analysis of replicate measurements and time-resolved spectra shows generally reproducible spectral response from MoCl5 vapors at 120 °C. The presence of HCl and MoOCl4 impurities in the MoCl5 vapor samples is determined to be unlikely based on the analysis of absorbance-pressure curves and spectral peak fitting. Comparison with MoOCl4 and MoO2Cl2 spectra shows a unique spectral fingerprint for MoCl5 at 28,500 cm-1 providing a convenient means of discriminating between MoCl5 and its oxychlorides in the visible wavelengths. Adsorption behavior of MoCl5 on surfaces is also discussed with particular emphasis on the use of MoCl5 as a reactant in vapor phase thin film deposition processes.

Electrochemical Monitoring of Super-Engineering Polymer Depolymerization: A Rapid and Simple Approach

The mechanical properties and processability of polymers are strongly influenced by their molecular weight, underscoring the critical importance of controlling depolymerization during storage in polymer synthesis and application. However, conventional methods of determining molecular weight, including viscosity measurements, gel permeation chromatography (GPC), and nuclear magnetic resonance (NMR) spectroscopy, typically necessitate substantial quantities of polymer samples and protracted measurement times. Moreover, certain polymers may undergo continuous degradation post-polymerization, rendering depolymerization analysis via traditional means highly challenging. Hence, there is an imperative need to develop novel analysis techniques that overcome these limitations and facilitate comprehensive depolymerization characterization.To surmount these challenges, we have developed a novel electrochemical method utilizing cyclic voltammetry to facilitate polymer depolymerization measurement. For measuring degree of depolymerization, we used thermal depolymerization process. As the polymer's molecular weight diminishes because of thermal depolymerization, the solution viscosity decreases correspondingly, thereby enabling unimpeded redox species diffusion and a proportional increase in steady-state current. By constructing a calibration curve of current versus thermal depolymerization time for a polymer, we can swiftly and accurately determine its molecular weight tendency in solution. Our investigations indicate that this electrochemical technique is more efficient and cost-effective as it necessitates smaller sample volumes and shorter measurement times than conventional methods, and it exhibits excellent potential for analyzing and maintaining polymer properties across various industries.[1] Kim, J. W., Kim, S. J., Song, I. Y., Lee, W. E., Heo, K., Kim, S. Y., ... & Kim, B. K. (2022). Simple and rapid electrochemical monitoring for depolymerization of polyamic acid. Analytica Chimica Acta, 1233, 340489.

Research on rapid extraction of internal resistance of lithium battery based on short-time transient response

Unlike laboratory measurements and online parameter observations based on long-term continuous operation data, offline fast measurement of battery parameters is widely used for convenient and accurate acquisition of battery parameters in battery production and maintenance processes. However, too short allowable measurement time in engineering results in a small amount of dynamic information that the algorithm can obtain and unclear initial state values, making it difficult to improve the accuracy of the algorithm. This paper employs a local coordinate system established in the vicinity of the measurement moment to extract the transient behavior of battery terminal voltage response under excitation current, and investigates the characterization capability of these transients on ohmic and polarization internal resistance of batteries at different time points. Moreover, based on an equivalent circuit model, it evaluates how initial values of transient voltage affect accuracy in calculating internal resistance. Through customized working condition verification, the selection principles for rapid identification of time points and the basic requirements for excitation conditions have been determined. Comparative verification of online parameter identification results based on continuous time series demonstrates that the fast identification algorithm can accurately identify Ohmic internal resistance and effectively characterize the variation law of battery polarization.