Reduce Measurement Time Research Articles

Multifocal hyperspectral Raman imaging setup for multi-well plates

High-throughput screening has become widespread in drug discovery. This increases the need for efficient, parallelized spectral imaging techniques. However, current designs focus on microplate readers without the capability of measuring hyperspectral images or microscopy setups. In this work, a novel setup for parallelized hyperspectral Raman spectroscopy is presented. Utilizing a unique combination of a diffractive element and a micro-lens array in a tailored optical setup, it was possible to acquire 64 high-resolution Raman spectra from a multi-well plate simultaneously. This allows an enormous reduction in measurement time in comparison to sequential readers. Thus, the presented parallelized hyperspectral Raman spectroscopic setup provides a time saving way for modern high-throughput screening applications and the advantage of chemically selective real-time comparison between the different micro-well spots.

A method for using Josephson voltage standards for direct characterization of high performance digitizers to establish AC voltage and current traceability to SI

A method for traceability to SI for ac voltage and current based on high performance digitizers is presented. In contrast to the existing thermal-based methods, the proposed method utilizes direct traceability to quantum-based waveforms via the use of Josephson voltage systems. This allows not only a simplification of the traceability chain and reduced measurement times but also offers the potential for analysis of the ac voltage and current waveform spectral content, a feature which is not possible using thermal methods. Scaling of current and voltage is achieved by the use of current shunts and resistive voltage dividers respectively. Target operating ranges are up to 1 A and 100 V with a frequency range up to 1 kHz for both. The corresponding target uncertainty for this traceability route is 1 μV V−1 and 2 μA A−1 up to frequencies of 1 kHz. The traceability chain is described and various components are characterized to validate their suitability for this task. It is demonstrated that these uncertainty targets can be met under certain conditions. The use of multi-tone calibration waveforms is investigated to further reduce measurement time. An uncertainty analysis method based on simulation using real component performance data is demonstrated.

Perimetric Comparison Between the IMOvifa and Humphrey Field Analyzer.

IMO visual function analyzer (IMOvifa), a binocular perimeter, has similar output to the Humphrey Field Analyzer (HFA), but reduced the measurement time. The purpose of this study is to evaluate the performance of IMOvifa, a perimeter that performs binocular visual field (VF) testing, and to compare its results with standard automated perimetry. All patients underwent HFA 24-2 SITA-Fast and IMOvifa 24-2 AIZE-Rapid on the same day. Mean deviation (MD), pattern SD (PSD), foveal threshold, and visual field index (VFI) were compared between the 2 perimeters using Wilcoxon signed-rank tests, Pearson correlation, and Bland-Altman plot. Measurement time for performing VF for both eyes was also collected for each device. In this cross-sectional study, 138 eyes (including 25 healthy, 48 glaucoma suspects, and 65 primary open angle glaucoma) of 69 patients were evaluated. Measurement time was significantly faster for IMOvifa compared with HFA (256 vs. 419s, P <0.001). No significant differences were seen in MD and VFI between HFA and IMOvifa (both P >0.05). Significant differences were seen in mean PSD 3.2 (2.7, 3.6) dB for HFA versus 4.1 (3.5, 4.6) for IMOvifa ( P <0.001), and foveal threshold 33.9 (33.1, 34.6) dB for HFA versus 30.6 (29.3, 31.9) dB for IMOvifa ( P <0.001). Pearson r was strong for MD ( r =0.90, P <0.001), PSD ( r =0.78, P <0.001), and VFI ( r =0.94, P <0.001). The mean difference (95% limits of agreement) was -0.1 (-3.8, 3.5) dB for MD, -0.4 (-3.4, 2.5) dB for PSD, and 0.1 (-8.9, 9.1) dB for VFI, respectively. IMOvifa reduced measurement time by 39%. MD, PSD, and VFI values for IMOvifa showed good agreement with HFA SITA-Fast strategy. This perimeter reduced fatigue for both patient and examiner. Additional studies are needed to determine whether it will be useful for routine VF testing.

Optimizing frequency sampling in CEST experiments.

For the past decade chemical exchange saturation transfer (CEST) experiments have been successfully applied to study exchange processes in biomolecules involving sparsely populated, transiently formed conformers. Initial implementations focused on extensive sampling of the CEST frequency domain, requiring significant measurement times. Here we show that the lengthy sampling schemes often used are not optimal and that reduced frequency sampling schedules can be developed without a priori knowledge of the exchange parameters, that only depend on the chosen B1 field, and, to a lesser extent, on the intrinsic transverse relaxation rates of ground state spins. The reduced sampling approach described here can be used synergistically with other methods for reducing measurement times such as those that excite multiple frequencies in the CEST dimension simultaneously, or make use of non-uniform sampling of indirectly detected time domains, to further decrease measurement times. The proposed approach is validated by analysis of simulated and experimental datasets.

Applications of image analysis in plant chromosome and chromatin structure study

BackgroundThe use of image analysis to understand the structure of chromosome and chromatin is critical to the study of genetic evolution and diversification. Furthermore, a detailed chromosome map and the structure of chromatin in the nucleus may contribute to the plant breeding and the study of fundamental biology and genetics in organisms.ResultsIn plants with a fully annotated genome project, such as the Leguminosae species, the integration of genetic information, including DNA sequence data, a linkage map, and the cytological quantitative chromosome map could further improve their genetic value. The numerical parameters of chromocenters in 3D can provide useful genetic information for phylogenetic studies of plant diversity and heterochromatic markers whose epigenetic changes may explain the developmental and environmental changes in the plant genome. Extended DNA fibers combined with fluorescence in situ hybridization revealed the highest spatial resolution of the obtained genome structure. Moreover, image analysis at the nano‐scale level using a helium ion microscope revealed the surface structure of chromatin, which consists of chromatin fibers compacted into plant chromosomes.ConclusionsThe studies described in this review sought to measure and evaluate chromosome and chromatin using the image analysis method, which may reduce measurement time and improve resolution. Further, we discussed the development of an effective image analysis to evaluate the structure of chromosome and chromatin. An effective application study of cell biology and the genetics of plants using image analysis methods is expected to be a major propeller in the development of new applications.

OsciCheck: A Novel Fluidic Transducer for Air-Coupled Ultrasonic Measurements

Ultrasonic measurement technology has become indispensable in NDT-CE. Air-coupled ultrasonic (ACU) measurement techniques promise to reduce measurement time. However, the signal quality suffers from large specific impedance mismatch at the transducer-air and air-specimen interface. Additionally, large pressure amplitudes are necessary for the penetration depth required in NDT-CE applications. To address the specific requirements of ultrasonic testing in NDT-CE, a robust ACU transducer was developed, that generates ultrasound by quickly switching a pressurized air flow. The simple design of the fluidic transducer makes the device maintenance free and resilient against harsh environmental conditions. Since the signal is generated by aeroacoustics, there is no specific impedance mismatch between the transducer and the surrounding air. The ultrasonic signal exhibits frequencies in the 30-60 kHz range and is therefore well suited to penetrate heterogenous materials such as concrete. This contribution gives an introduction in the working principle and signal characteristics of the fluidic transducer. Its application on different materials is validated. A detailed outlook is given to discuss the future potential of fluidic ultrasonic actuators.

Efficient Near-Field Radiofrequency Imaging of Impact Damage on CFRP Materials with Learning-Based Compressed Sensing.

Carbon fiber-reinforced polymer (CFRP) is a widely-used composite material that is vulnerable to impact damage. Light impact damages destroy the inner structure but barely show obvious change on the surface. As a non-contact and high-resolution method to detect subsurface and inner defect, near-field radiofrequency imaging (NRI) suffers from high imaging times. Although some existing works use compressed sensing (CS) for a faster measurement, the corresponding CS reconstruction time remains high. This paper proposes a deep learning-based CS method for fast NRI, this plugin method decreases the measurement time by one order of magnitude without hardware modification and achieves real-time imaging during CS reconstruction. A special 0/1-Bernoulli measurement matrix is designed for sensor scanning firstly, and an interpretable neural network-based CS reconstruction method is proposed. Besides real-time reconstruction, the proposed learning-based reconstruction method can further reduce the required data thus reducing measurement time more than existing CS methods. Under the same imaging quality, experimental results in an NRI system show the proposed method is 20 times faster than traditional raster scan and existing CS reconstruction methods, and the required data is reduced by more than 90% than existing CS reconstruction methods.

Using digital technologies to study the behavior of rubber balloons

In this paper, we have demonstrated the feasibility of using digital technologies to study the behavior of rubber balloons. The experiment to study the behavior of balloons was presented in a new way using the Vernier measuring system, Logger Pro 3 software, Tracker and Google Sheets. This allowed to significantly optimize the work, reduce measurement time and increase the time required to calculate and analyze the results.

New data processing method for nuclear material measurement using pulsed neutrons

Active neutron methods using pulsed neutrons are used to detect the presence of nuclear materials. In this study, we investigated a new data processing method and compared its performance to a conventional method. It is shown that the new method offers a significant reduction in measurement time and an increased sensitivity.

An Analysis on the Reduction of Measurement Time Using Interpolation Algorithm in Near-field RCS Measurements for Aircraft Shape

The importance of stealth technology is increasing in modern warfare, and Radar Cross Section(RCS) is widely used as an indicator of stealth technology. It is useful to measure RCS using an image-based near-field to far-field transformation algorithm in short-range monostatic conditions. However, the near-field measurement system requires a longer measurement time compared to other methods. In this work, it is proposed to reduce the measured data using an interpolation method in azimuth angular domain. The calculated far-field RCS values according to the sampling rate is shown, and the performance of the algorithm applied with interpolation in the angular domain is presented. It is shown that measurement samples can be reduced several times by using the redundancy in the angular domain while producing results similar to the conventional method.

Fourier-based decomposition for simultaneous 2-voxel MRS acquisition with 2SPECIAL.

To simultaneously acquire spectroscopic signals from two MRS voxels using a multi-banded 2 spin-echo, full-intensity acquired localized (2SPECIAL) sequence, and to decompose the signal to their respective regions by a novel voxel-GRAPPA (vGRAPPA) decomposition approach for in vivo brain applications at 7 T. A wideband, uniform rate, smooth truncation (WURST) multi-banded pulse was incorporated into SPECIAL to implement 2SPECIAL for simultaneous multi-voxel spectroscopy (sMVS). To decompose the acquired data, the voxel-GRAPPA decomposition algorithm is introduced, and its performance is compared to the SENSE-based decomposition. Furthermore, the limitations of two-voxel excitation concerning the multi-banded adiabatic inversion pulse, as well as of the combined B0 shim and B1 + adjustments, are evaluated. It was successfully shown that the 2SPECIAL sequence enables sMVS without a significant loss in SNR while reducing the total scan time by 21.6% compared to two consecutive acquisitions. The proposed voxel-GRAPPA algorithm properly reassigns the signal components to their respective origin region and shows no significant differences to the well-established SENSE-based algorithm in terms of leakage (both <10%) or Cramér-Rao lower bounds (CRLB) for in vivo applications, while not requiring the acquisition of additional sensitivity maps and thus decreasing motion sensitivity. The use of 2SPECIAL in combination with the novel voxel-GRAPPA decomposition technique allows a substantial reduction of measurement time compared to the consecutive acquisition of twosingle voxels without a significant decrease in spectral quality or metabolite quantification accuracy and thus provides a new option for multiple-voxel applications.

Multi-beam heterodyne laser Doppler vibrometer based on a line-scan CMOS digital camera.

Multi-beam laser Doppler vibrometers (MB-LDVs) have an advantage over scanning single-beam laser Doppler vibrometers (LDVs) due to the reduction in measurement time and their ability to measure non-stationary and transient events. However, the number of simultaneously interrogated points in current MB-LDVs is limited due to the complexity of the electronic hardware, which increases with the number of measurement channels. Recent developments of high-speed line-scan CMOS cameras suggest that their use in MB-LDVs can reduce the hardware complexity and increase the number of measurement channels. We developed a MB-LDV based on a digital line-scan CMOS camera that simultaneously measures vibrations on a linear array of 99 points. The experimental setup and performance of the developed MB-LDV are discussed in this paper.

Modified Plett-model for modeling voltage hysteresis in lithium-ion cells

Lithium-ion cells, especially anode materials like graphite or silicon, exhibit a charge-direction dependent voltage hysteresis. In literature, several approaches exist to model this effect. This paper aims at showing modifications to the so called Plett-model. It will be shown that the specific slope of the transition between charge and discharge OCV curves can be linked to the slope of the OCV curves themselves. This leads to a significant reduction in measurement and parameterization time. Furthermore, this paper features the application of the improved model to composite electrodes. The separation of the contributions of graphite and silicon leads to an improved modeling of the total voltage hysteresis.

Dynamic Down-Selection of Measurement Markers for Optimized Robust Control of Overlay Errors in Photolithography Processes

Control of overlay errors in lithography process in semiconductor manufacturing uses in-process measurements of overlay errors from markers distributed across a wafer to adapt controllable process parameters on the relevant lithography tools in order to minimize future errors. Intuitively speaking, the use of a larger number of measurement markers should lead to improvements in one’s ability to control the overlay errors. However, those gains come with simultaneous increases in the metrology times, which negatively impacts throughput. Therefore, one should carefully and strategically select markers which most efficiently enable suppression of overlay errors. This paper proposes a novel optimization framework that couples a recently introduced approach for robust control of overlay errors in photolithography processes with a strategic selection of overlay measurement markers to enable improved control of overlay errors using a reduced number of measurements. Application of the newly proposed method to the data and models from an industrial-scale semiconductor lithography process shows that the newly proposed combination of the robust overlay control paradigm and optimized marker selection enables improved overlay control, even with a significantly reduced number of markers. Thus, the new methodology enables reduction of measurement times and subsequent overall cycle times, without deteriorating the outgoing product quality.

Modeling of Key Specifications for RF Amplifiers Using the Extreme Learning Machine.

The amplifier is a key component of the radio frequency (RF) front-end, and its specifications directly determine the performance of the system in which it is located. Unfortunately, amplifiers’ specifications degrade with temperature and even lead to system failure. To study how the system failure is affected by the amplifier specification degradation, it is necessary to couple the amplifier specification degradation into the system optimization design. Furthermore, to couple the amplifier specification degradation into the optimal design of the system, it is necessary to model the characteristics of the amplifier specification change with temperature. In this paper, the temperature characteristics of two amplifiers are modeled using an extreme learning machine (ELM), and the results show that the model agrees well with the measurement results and can effectively reduce measurement time and cost.

Non-destructive characterisation of out-of-plane fibre waviness in carbon fibre reinforced polymers by X-ray dark-field radiography

ABSTRACT Fibre waviness is a frequently encountered problem in composite design and manufacturing as it can severely influence mechanical properties of components. In this work, we propose a new method for the detection and quantification of out-of-plane fibre waviness in carbon fibre composites using Talbot-Lau grating interferometry. The sensitivity of X-ray dark-field imaging to the orientation of carbon fibres is exploited to visualise fibre waviness by radiographic imaging and reduce measurement times in comparison to full computed tomography scans. We show that fibre waviness can be qualitatively detected by single radiographic images providing a valid option, for example, for in-line monitoring of similar specimens. Furthermore, quantitative evaluation of fibre waviness angles can be performed by repeated radiographic imaging over an angular range of roughly 10°. Therefore, the number of required projection images can be reduced significantly. With this method, we evaluated wave angles at an error of less than ±1.5° compared to results achieved by full computed tomography scans.

The Effect of Inter-pulse Interval on TMS Motor Evoked Potentials in Active Muscles.

ObjectiveThe time interval between transcranial magnetic stimulation (TMS) pulses affects evoked muscle responses when the targeted muscle is resting. This necessitates using sufficiently long inter-pulse intervals (IPIs). However, there is some evidence that the IPI has no effect on the responses evoked in active muscles. Thus, we tested whether voluntary contraction could remove the effect of the IPI on TMS motor evoked potentials (MEPs).MethodsIn our study, we delivered sets of 30 TMS pulses with three different IPIs (2, 5, and 10 s) to the left primary motor cortex. These measurements were performed with the resting and active right hand first dorsal interosseous muscle in healthy participants (N = 9 and N = 10). MEP amplitudes were recorded through electromyography.ResultsWe found that the IPI had no significant effect on the MEP amplitudes in the active muscle (p = 0.36), whereas in the resting muscle, the IPI significantly affected the MEP amplitudes (p < 0.001), decreasing the MEP amplitude of the 2 s IPI.ConclusionsThese results show that active muscle contraction removes the effect of the IPI on the MEP amplitude. Therefore, using active muscles in TMS motor mapping enables faster delivery of TMS pulses, reducing measurement time in novel TMS motor mapping studies.

Non-destructive characterization of out-of-plane fiber waviness in carbon fiber reinforced polymers by X-ray dark-field radiography

Fibre waviness is a frequently encountered problem in composite design and manufacturing as it can severely influence mechanical properties of components. In this work we propose a new method for the detection and quantification of out-of-plane fibre waviness in carbon fibre composites using Talbot-Lau grating interferometry. The sensitivity of X-ray dark-field imaging to the orientation of carbon fibres is exploited to visualize fibre waviness by radiographic imaging and reduce measurement times in comparison to full computed tomography scans. We show that fibre waviness can be qualitatively detected by single radiographic images providing a valid option, e.g. for in-line monitoring of similar specimens. Furthermore, quantitative evaluation of fibre waviness angles can be performed by repeated radiographic imaging over an angular range of roughly 10°. Therefore, the number of required projection images can be reduced significantly. With this method, we evaluated wave angles at an error of less than ±1.5° compared to results achieved by full computed tomography scans.

OrthoChirp: A fast spectro-mechanical probe for monitoring transient microstructural evolution of complex fluids during shear

Shear-induced microstructural changes are observed ubiquitously in materials as diverse as hydrogels, or drilling fluids, as well as many consumer products. Superposition rheometry, consisting of superimposing Small Amplitude Oscillatory Shear (SAOS) on top of a constant rate unidirectional shear has often been used to gain insight into these shear-induced changes. Orthogonal superposition (OSP), in which the two modes of deformation are perpendicular, has been preferred over parallel superposition to avoid non-linear cross-coupling of the steady shear and small amplitude oscillatory deformation fields. This cross-coupling can lead to unphysical sign changes in the measured material properties, and makes it difficult to unambiguously interpret the flow-induced mechanical properties. Recently, orthogonal superposition has been used to investigate the shear-induced anisotropy produced in colloidal gels by comparing the transient evolution of the orthogonal moduli with the parallel moduli immediately after cessation of shear. However, probing transient evolution using the OSP technique can be challenging for rapidly mutating complex materials which evolve on time scales comparable to the time scale of the experiment. Using a weakly associated alginate gel, we demonstrate the potential to substantially reduce the measurement time by superimposing fast Optimally Windowed Chirp (OWCh) deformations orthogonally to the steady shearing deformation. We evaluate the changes in the rate-dependent relaxation spectrum in the direction of the applied unidirectional shear rate, as well as in the orthogonal direction, by measuring the damping function and shear-induced changes in the orthogonal moduli respectively. We observe systematic differences between the two sets of spectra that we measure in the two orthogonal directions, enabling us to quantify the flow-induced generation of microstructural anisotropy in the alginate gel. • Reduction of measurement time for orthogonal superposition (OSP) rheometry. • Possible to superpose optimally windowed chirps (OWCh) orthogonally to steady shear. • Shear flow induces microstructural anisotropy in weakly associating alginate gels. • Observation of transient evolutions in rapidly mutating complex materials • Different rate-dependent relaxation spectra in orthogonal directions.

FishSizer: Software solution for efficiently measuring larval fish size

Length and depth of fish larvae are part of the fundamental measurements in many marine ecology studies involving early fish life history. Until now, obtaining these measurements has required intensive manual labor and the risk of inter‐ and intra‐observer variability.We developed an open‐source software solution to semi‐automate the measurement process and thereby reduce both time consumption and technical variability. Using contrast‐based edge detection, the software segments images of a fish larva into “larva” and “background.” Length and depth are extracted from the “larva” segmentation while taking curvature of the larva into consideration. The graphical user interface optimizes workflow and ease of usage, thereby reducing time consumption for both training and analysis. The software allows for visual verification of all measurements.A comparison of measurement methods on a set of larva images showed that this software reduces measurement time by 66%–78% relative to commonly used software.Using this software instead of the commonly used manual approach has the potential to save researchers from many hours of monotonous work. No adjustment was necessary for 89% of the images regarding length (70% for depth). Hence, the only workload on most images was the visual inspection. As the visual inspection and manual dimension extraction works in the same way as currently used software, we expect no loss in accuracy.