Absolute Measurements Research Articles

1520: Characterization of EBT, EBT-XD and OC-1 Films for Absolute Dose measurement in Electron Beams

1520: Characterization of EBT, EBT-XD and OC-1 Films for Absolute Dose measurement in Electron Beams

Dual-comb parallel sampling absolute distance measurements with an extended non-ambiguity range

Dual-comb parallel sampling absolute distance measurements with an extended non-ambiguity range

Quantification of the Uncertainty in Ultrasonic Wave Speed in Concrete: Application to Temperature Monitoring with Embedded Transducers.

This article presents an overall examination of how small temperature fluctuations affect P-wave velocity (Vp) measurements and their uncertainties in concrete using embedded piezoelectric transducers. This study highlights the fabrication of custom transducers tailored for long-term concrete monitoring. Accurate and reliable estimation of ultrasonic wave velocities is challenging, since they can be impacted by multiple experimental and environmental factors. In this work, a reliable methodology incorporating correction models is introduced for the quantification of uncertainties in ultrasonic absolute and relative velocity measurements. The study identifies significant influence quantities and suggests uncertainty estimation laws, enhancing measurement accuracy. Determining the onset time of the signal is very time-consuming if the onset is picked manually. After testing various methods to pinpoint the onset time, we selected the Akaike Information Criterion (AIC) due to its ability to produce sufficiently reliable results. Then, signal correlation was used to determine the influence of temperature (20 °C to 40 °C) on Vp in different concrete samples. This technique proved effective in evaluating velocity changes, revealing a persistent velocity decrease with temperature increases for various concrete compositions. The study demonstrated the capability of ultrasonic measurements to detect small variations in the state of concrete under the influence of environmental variables like temperature, underlining the importance of incorporating all influencing factors.

Absolute Stenosis Measures of Renal Artery Independently Influence Kidney Perfusion in Contrast-Enhanced Multidetector Computed Tomography.

Background: A renal artery lumen reduction of ≥60% indicates hemodynamically significant stenosis and is one of the main criteria for invasive revascularization. We hypothesize that direct parameters describing renal artery stenosis (RAS) could better correlate with renal blood flow and improve the criterion for revascularization. This study aimed to investigate RAS parameters independently associated with renal blood flow estimated in contrast-enhanced multidetector computed tomography (CE-MDCT). Methods: Ultrasound Doppler dynamic renal cortical perfusion (dRCP), CE-MDCT with cortical blood flow (CBF), and RAS assessment in the form of cross-sectional area reduction (CSAR), maximal diameter reduction (MaxDR), mean diameter (MeD), and minimal diameter (MinD) were investigated. Results: CBF correlated with CSAR (r = -0.422, p = 0.003), MeD (r = 0.344, p = 0.005) and MinD (r = 0.348, p= 0.005), whereas RCP correlated only with MeD (r = 0.357, p = 0.005) and MinD (r = 0.427, p< 0.001). In multivariable regression, only MeD was independently associated with CBF (R2 = 0.179; p < 0.001), and MeD < 3.5 mm substantially indicated CBF < 175 mL/100 g/min in ROC analysis. Conclusions: The directly measured mean diameter of RAS is independently associated with renal cortex blood flow and is probably a more appropriate parameter for the invasive RAS treatment criterion.

Microwave photonics frequency scanning approach to absolute distance measurement

An absolute distance measurement approach based on microwave photonics is proposed to provide a high-resolution and non-ambiguity range measurement solution by microwave frequency scanning. The microwave interference spectrum containing optical path difference information can be generated through two rounds of intensity modulation. The approach combines the characteristics of easy focusing and collimation of light waves, as well as easy manipulation of microwaves, to achieve accurate absolute distance measurement. The experimental results show that high-precision measurements can be achieved within the frequency scanning range of only 2 GHz. The error of the distance measurement is less than ±0.079 mm. In addition, the effectiveness of the scanning pattern and the data processing algorithm are verified.

Double ended frequency-scanning heterodyne interferometer for absolute length measurement of opaque blocks

A new contactless method based on frequency-scanning heterodyne interferometry is proposed to measure the absolute length of opaque blocks with fragile reflective surfaces. This method is significant in scientific research, such as determining the absolute length of torsion pendulums in gravitational experiments or test masses in gravitational wave detection programs. In addition to avoiding possible damage caused by contact measurement, this optical setup has the potential for higher measurement accuracy compared to contact measurement apparatuses. Two gauge blocks with nominal lengths of 40 mm and 50 mm are used to test the performance of the proposed interferometer, and the measurement results closely match their nominal lengths. The combined uncertainty is 0.62μm and 0.48μm for the 40 mm and 50 mm gauge blocks respectively.

Multiparametric Methods for Rapid Classification of Diesel Fuel Quality Used in Automotive Engine Systems

Fuels should behave appropriately in all sections of the engine system: the engine, fuel delivery system, and tank. Fuel quality can be linked to the following three crucial areas: performance, fitness for current use, and stability. Classical methods of diesel fuel examination mostly rely on the absolute value measurement of one specific parameter while stabilizing outside conditions. In contrast, multiparametric methods depend on simultaneously measuring a set of parameters. Therefore, multiparametric methods open the possibility of intriguing new examinations and classifications of diesel fuel quality while raising specific issues relating to the instrumentation and construction of sensing devices. This paper presents a review, based on the published literature and the authors’ research, of the current state-of-the-art multiparametric methods for rapid diesel fuel quality classification and related instrumentation, systematizing the various types of methods from the point of view of the principles of their operation. The main conclusion is that different measuring procedures use similar methods of data processing. Moreover, the heavy, costly, and complex devices that enable standard examinations can be converted to simpler devices in the future, whose cost of use is significantly lower. However, to achieve this, progress in electronic devices is required.

Stressing the Relevance of Differentiating between Systematic and Random Measurement Errors in Ultrasound Muscle Thickness Diagnostics

BackgroundThe majority of studies that explore changes in musculature following resistance training interventions or examine atrophy due to immobilization or sarcopenia use ultrasound imaging. While most studies assume acceptable to excellent reliability, there seems to be unawareness of the existing absolute measurement errors. As early as 1998, methodological research addressed a collective unawareness of the random measurement error and its practical indications. Referring to available methodological approaches, within this work, we point out the limited value of focusing on relative, correlation-based reliability indices for the interpretability in scientific research but also for clinical application by assessing 1,512 muscle thickness values from more than 400 ultrasound images. To account for intra- and inter-day repeatability, data were collected on two consecutive days within four testing sessions. Commonly-stated reliability values (ICC, CV, SEM and MDC) were calculated, while evidence-based agreement analyses were applied to provide the accompanied systematic and random measurement error.ResultsWhile ICCs in the range of 0.832 to 0.998 are in accordance with the available literature, the mean absolute percentage error ranges from 1.34 to 20.38% and the mean systematic bias from 0.78 to 4.01 mm (all p ≤ 0.013), depending on the measurement time points chosen for data processing.ConclusionsIn accordance with prior literature, a more cautious interpretation of relative reliability values should be based on included systematic and random absolute measurement scattering. Lastly, this paper discusses the rationale for including different measurement error statistics when determining the validity of pre-post changes, thus, accounting for the certainty of evidence.

Towards optical measurements of membrane potential values in Bacillus subtilis using fluorescence lifetime.

Membrane potential (MP) changes can provide a simple readout of bacterial functional and metabolic state or stress levels. While several optical methods exist for measuring fast changes in MP in excitable cells, there is a dearth of such methods for absolute and precise measurements of steady-state membrane potentials (MPs) in bacterial cells. Conventional electrode-based methods for the measurement of MP are not suitable for calibrating optical methods in small bacterial cells. While optical measurement based on Nernstian indicators have been successfully used, they do not provide absolute or precise quantification of MP or its changes. We present a novel, calibrated MP recording approach to address this gap. In this study, we used a fluorescence lifetime-based approach to obtain a single-cell resolved distribution of the membrane potential and its changes upon extracellular chemical perturbation in a population of bacterial cells for the first time. Our method is based on (i) a unique VoltageFluor (VF) optical transducer, whose fluorescence lifetime varies as a function of MP via photoinduced electron transfer (PeT) and (ii) a quantitative phasor-FLIM analysis for high-throughput readout. This method allows MP changes to be easily visualized, recorded and quantified. By artificially modulating potassium concentration gradients across the membrane using an ionophore, we have obtained a Bacillus subtilis-specific MP versus VF lifetime calibration and estimated the MP for unperturbed B. subtilis cells to be -65 mV and that for chemically depolarized cells as -14 mV. We observed a population level MP heterogeneity of ~6-10 mV indicating a considerable degree of diversity of physiological and metabolic states among individual cells. Our work paves the way for deeper insights into bacterial electrophysiology and bioelectricity research.

Physical Fitness and Exercise Performance of Transgender Women.

In spite of the evolving participation of transgender adults in exercise and sports, research investigating the physical fitness of transgender women remains scarce in the scientific literature. In this cross-sectional study, a variety of reference-standard measures of physical fitness of transgender women who had undergone gender-affirming orchiectomy (30 ± 4 years; n = 15) and who had not (27 ± 4 years: n = 15) were compared with reference males (28 ± 5 years; n = 15) and reference females (29 ± 5 years; n = 15) who were matched for age and estimated physical activity level. Transgender women had been undergoing feminizing gender-affirming therapy for 8-10 years. Height and lean mass of arms, legs, and trunk (measured via DXA) of transgender women were greater than those of reference females but lower than those of reference males (all p < 0.05). No significant differences were in isokinetic muscular torque found between reference females and transgender women. Both absolute and relative measures of maximal oxygen consumption were greater in reference males than in reference females and transgender women (all p < 0.05) with no significant difference between the latter two groups. Reference males had greater peak Wingate anaerobic power (expressed in both absolute and relative to body weight), countermovement jump, and squat jump than reference females and transgender women (all p < 0.05). There were no significant differences in anaerobic power between reference females and transgender women. The results on the field tests, including agility T-test and sprint running acceleration, were consistent with the anaerobic power tests. There were no statistical differences in any of the physical fitness measures between transgender women with and without orchiectomy. Transgender women demonstrated similar levels of reference-standard measures of physical fitness to females that were significantly lower than males.

The muon beam monitor for the FAMU experiment: design, simulation, test, and operation

FAMU is an INFN-led muonic atom physics experiment based at the RIKEN-RAL muon facility at the ISIS Neutron and Muon Source (United Kingdom). The aim of FAMU is to measure the hyperfine splitting in muonic hydrogen to determine the value of the proton Zemach radius with an accuracy better than 1%. The experiment has a scintillating-fibre hodoscope for beam monitoring and data normalisation. In order to carry out muon flux estimation, low-rate measurements were performed to extract the single-muon average deposited charge. Then, detector simulation in Geant4 and FLUKA allowed a thorough understanding of the single-muon response function, which is crucial for determining the muon flux. This work presents the design features of the FAMU beam monitor, along with the simulation and absolute calibration measurements in order to enable flux determination and enable data normalisation.

Effect of Macroeconomic Variables on Economic Growth in Nigeria

The study examined the effect of macro-economic variables on economic growth in Nigeria between 1990-2022. Specifically, the paper examined the effect of Exchange rate on Economic growth in Nigeria and determined the effect of interest rate on Economic growth in Nigeria. The paper employed ex-facto research design, using secondary data and adopted SVAR model. The paper found out that interest rate has a significant effect on Economic growth (RGDP) in Nigeria, and found that exchange rate has a significant effect on Economic growth (RGDP) in Nigeria. The study concluded that macroeconomic variables has a significant effect on Economic growth in Nigeria. Based on the study’s findings and conclusions above, the following recommendations were made: the government should improve on her foreign reserves as an absolute measure that will stabilize exchange rate to boost economic environment for effective investment to thrive and contribute to gross domestic product in Nigeria, and interest rate is found to have increased the potentials of Economic growth in Nigeria. It is therefore important to note that since interest rate have significantly affected the Economic growth in Nigeria, the CBN should improve on discount rate to stabilize interest rate to boost economic environment for effective investment to thrive and contribute to gross domestic product in Nigeria.

Application of the CIEMAT/NIST method to 14C low-level measurements

Radiocarbon dating of samples from benzene synthesis by low-level Liquid Scintillation Counting (LSC) method requires the availability of 14C standards in benzene, which are difficult to obtain, or the use of an absolute measurement which is out of reach for most analytical laboratories. This paper describes how the CIEMAT/NIST method can help to solve this issue and presents the measurements of low activity concentrations performed in the LRI-D using two different benzene base scintillator cocktails.

Wavefront sensing with a gradient phase filter

Wavefront sensors have now become core components in the fields of metrology of optical systems, biomedical optics, and adaptive optics systems for astronomy. However, none of the designs used or proposed so far achieve simultaneously a high spatial resolution at the pupil of the tested optics and absolute measurement accuracy comparable to those of modern laser-interferometers. This paper presents an improved wavefront sensor concept that reaches both previous goals. This device named Crossed-sine phase sensor (CSPS) is based on a fully transparent gradient phase filter (GPF) placed at an intermediate location between the virtual pupil and image planes of the tested optics. The theoretical principle of the sensor is described in Fourier optics formalism. Numerical simulations confirm that a measurement accuracy of λ/100 RMS is achievable. The CSPS also offers the advantages of being quasi-achromatic and working on spatially or spectrally extended, natural or artificial light sources.

Trends and inequalities in neonatal mortality rate in Bangladesh: Evidence from cross-sectional surveys.

Given the significance of addressing neonatal mortality in pursuing the 2030 Sustainable Development Goal on child health, research focus on this area is crucial. Despite the persistent high rates of neonatal mortality rate (NMR) in Bangladesh, there remains a notable lack of robust evidence addressing inequalities in NMR in the country. Therefore, this study aims to fill the knowledge gap by comprehensively investigating inequalities in NMR in Bangladesh. The Bangladesh Demographic and Health Survey (BDHS) data from 2000 to 2017 were analyzed. The equity stratifiers used to measure the inequalities were wealth status, mother's education, place of residence, and subnational region. Difference (D) and population attributable fraction (PAF) were absolute measures, whereas population attributable risk (PAR) and ratio (R) were relative measures of inequality. Statistical significance was considered by estimating 95% confidence intervals (CIs) for each estimate. A declining trend in NMR was found in Bangladesh, from 50.2 in 2000 to 31.9 deaths per 1000 live births in 2017. This study detected significant wealth-driven (PAF: -20.6, 95% CI: -24.9, -16.3; PAR: -6.6, 95% CI: -7.9, -5.2), education-related (PAF: -11.6, 95% CI: -13.4, -9.7; PAR: -3.7, 95% CI: -4.3, -3.1), and regional (PAF: -20.6, 95% CI: -27.0, -14.3; PAR: -6.6, 95% CI: -8.6, -4.6) disparities in NMR in all survey points. We also found a significant urban-rural inequality from 2000 to 2014, except in 2017. Both absolute and relative inequalities in NMR were observed; however, these inequalities decreased over time. Significant variations in NMR across subgroups in Bangladesh highlight the need for comprehensive, and targeted interventions. Empowering women through improved access to economic resources and education may help address disparities in NMR in Bangladesh. Future research and policies should focus on developing strategies to address these disparities and promote equitable health outcomes for all newborns.

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The average density of the undecelerated H atom beam is approximately an order of magnitude higher (2.9 ± 1.9) ×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ imes $$\\end{document} 105\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^5$$\\end{document} cm-3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{-3}$$\\end{document}, with the average density of the molecular ammonia beam over two orders of magnitude higher again (5.1 ± 2.9) ×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ imes $$\\end{document} 107\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^7$$\\end{document} cm-3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{-3}$$\\end{document}. The average number densities measured for the two different species of interest in this work span more than three orders of magnitude. These findings highlight the need for accurate and precise experimental measurements of number densities—for each species of interest, under the appropriate experimental conditions—before doing absolute rate coefficient calculations.Graphical abstract

How Good Are We Really? Underestimating the Extent of Obstructive CAD With SPECT and PET Relative Myocardial Perfusion Imaging and With PET Absolute Myocardial Blood Flow Measurement

How Good Are We Really? Underestimating the Extent of Obstructive CAD With SPECT and PET Relative Myocardial Perfusion Imaging and With PET Absolute Myocardial Blood Flow Measurement

An Energy-Efficient FD-fNIRS Readout Circuit Employing a Mixer-First Analog Frontend and a Σ-Δ Phase-to-Digital Converter.

This paper presents a low-power frequency-domain functional near-infrared spectroscopy (FD-fNIRS) readout circuit for the absolute value measurement of tissue optical characteristics. The paper proposes a mixer-first analog front-end (AFE) structure and a 1-bit Σ-Δ phase-to-digital converter (PDC) to reduce the required circuit bandwidth and the laser modulation frequency, thereby saving power while maintaining high resolution. The proposed chip achieves sub-0.01° phase resolution and consumes 6.8 mW of power. Nine optical solid phantoms are produced to evaluate the chip. Compared to a self-built high-precision measurement platform that combines a network analyzer with an avalanche photodiode (APD) module, the maximum measuring errors of the absorption coefficient and reduced scattering coefficient are 10.6% and 12.3%, respectively.

Absolute wall thickness measurement of conducting plates using pulsed eddy currents

Absolute wall thickness measurement of conducting plates using pulsed eddy currents

Development of a measuring technique based on JET second D-T campaign (DTE2) experience for assessing fusion power at ITER during D-T operation using the radial gamma-ray spectrometer.

The ITER Radial Gamma-Ray Spectrometer (RGRS) consists of three gamma-ray detectors observing the plasma through three collimated, coplanar, radial lines of sight (LoS). The system was initially designed to monitor the runaway electron emission and the alpha-particle density profile [Nocente etal., Nucl. Fusion 57, 076016 (2017)]. This work presents a novel technique for measuring the fusion power during D-T operation using the RGRS. This method is based on the absolute measurement of the 17MeV fusion gamma-rays and a semi-analytical computation of their transport from the plasma source to the detectors. This approach was initially developed and tested at JET during the second D-T campaign (DTE2) on a single LoS diagnostic [Dal Molin etal., Phys. Rev. Lett. (submitted) (2024); Rebai etal., Phys. Rev. C (submitted) (2024); and Marcer etal., Nucl. Fusion (unpublished) (2024)]. This work exploits the multiple LoS of the RGRS to create a combined virtual diagnostic whose detected fraction of the total plasma emission is less affected by variations in the plasma emission profile, reducing systematic uncertainties on the estimated total emission, compared to the individual detectors.