Absolute Intensity Values Research Articles

Sound of natural and artificial rain impact on ETFE membranes

Thin membranes are known to produce a drum-like effect when subjected to rainfall. Rain noise affects acoustic comfort and might disrupt communication, speech intelligibility and cognitive task performance. Therefore, assessment of the characteristics of noise produced by impact of rain on membranes in different architectural settings is important. Given inherent disparities between natural and artificial precipitation-primarily in terms of droplet size distribution and terminal velocities-underscores the importance of conducting evaluations using natural rain noise. The focus of this study is on the comparative assessment of the sound generated by natural rainfall versus the sound generated by the impact of individual droplet in a semi-anechoic room on single Ethylene tetrafluoroethylene (ETFE) membranes. The study assesses the extent of spectral variations of the rain sound produced in both approaches and the corresponding absolute value of noise intensity.

EUV Radiation in the Range of 10–20 nm from Liquid Spray Targets Containing O, Cl, Br and I Atoms under Pulsed Laser Excitation

The article describes the results of an investigation to determine the values of radiation intensities emitted by O-, Cl-, Br-, and I-containing liquid spray targets in absolute units in the wavelength range 10–20 nm when excited by pulsed laser radiation. The conversion coefficients of laser radiation into the EUV radiation are given for some wavelengths. The authors’ specially designed pulse extrusion liquid supply system was used to form the liquid spray targets. An Nd:YAG laser with λ = 1064 nm, τ = 8.4 ns, and Epulse = 0.8 J was used to excite the targets. Spectral measurements were made using a grazing incidence grating spectrometer–monochromator. The absolute intensities of a number of emission lines were also measured using a Bragg spectrometer based on a Mo/Be multilayer X-ray mirror, calibrated by both sensitivity and wavelength. The high values of absolute intensities of the liquid targets in the extreme ultraviolet wavelength range were demonstrated.

Application of Т1, Т2‑mapping technique for evaluation of intracranial meningioma consistency

Background. Meningiomas are the most common extracerebral intracranial neoplasms. Radicality of meningioma resection largely depends on its consistency, size, and closeness to important anatomical structures. Preoperative prognosis of meningioma density plays an important role in selection of surgical access and operative inventory, general radicality of tumor resection, and neurological outcome after surgery.Aim. To determine predictors of intracranial meningioma consistency using magnetic resonance imaging and T1, T2‑mapping technique.Materials and methods. The study included 96 patients with primary meningiomas who underwent surgery at the Federal Neurosurgical Center (Novosibirsk) between 2018 and 2021. Magnetic resonance images were analyzed using calculation of the ratio between signal intensity on T1‑weighted and T2‑weighted images with subsequent group and correlation statistical analysis for comparison of T1, T2‑mapping results with clinical, histological and intraoperative data.Results. Statistically significant increase in the signal intensity and standard deviation from the mean intensity on T1, T2‑maps of psammomatous meningiomas compared to all other subtypes was observed. Additionally, positive correlation between signal intensity form meningiomas on T1, T2‑maps and intraoperative data on tumor consistency was found.Conclusion. Images obtained using T, T2‑mapping technique are as informative as traditional T2‑weighted images for evaluation of intracranial meningioma consistency. Additionally, they allow to obtain absolute intensity values. Further prospective studies are necessary for confirmation of the obtained results.

INVESTIGATION OF SPATIAL DISTRIBUTION OF METAL VAPOURS ADMIXTURES IN THE PLASMA OF AN ELECTRIC ARC DISCHARGE

This work focuses on diagnosing the plasma in an electric arc discharge in an argon flow using optical emission spectroscopy. The method employed for determining the population of energy levels and the concentration of metal atoms based on the absolute values of emission intensity is described and validated. The experimental setup includes a spectrograph and an RGB CMOS matrix as the emission registration device. By obtaining the absolute values of the spectral radiances of Cu I lines and considering the axial symmetry of the electric arc discharge, the local radiation intensity of these lines is determined. Radial distributions of copper atom concentrations are then calculated using the absolute values of emission intensities and the radial distribution of the excitation temperature, which is determined using the Boltzmann plots technique. Two methods are employed for calculating the atom concentrations. The first method involves Boltzmann plots based on four spectral lines of Cu I and the corresponding excitation temperature. The second method determines the concentrations directly from the population of copper's energy levels, which are derived from the absolute values of emission intensity of the Cu I spectral lines. The results obtained from these two methods exhibit a coincidence of within 20%, supporting the recommendation of this technique for plasma diagnostics in electric arc discharges.

Experimental Confirmation of the Optoelectronic Reciprocity Theorem in High-Efficiency CuIn1−xGaxSe2 Solar Cells

The optoelectronic reciprocity theorem has been proposed as a theorem relating electroluminescence (EL) and photovoltaic external quantum efficiency in solar cells. The theorem is vital for a fundamental understanding of solar cell operation and its application to device evaluation. Furthermore, with this theorem, it is also possible to estimate the open-circuit voltage (${V}_{\mathrm{OC}}$) of solar cells using the external radiative efficiency (${\ensuremath{\eta}}_{\mathrm{ext}}$) obtained from the absolute value of EL emission intensity, even for solar cells for which we cannot directly measure ${V}_{\mathrm{OC}}$, such as subcells of multijunction solar cells or individual $\mathrm{Si}$ cells in modules and arrays. However, it is not a priori obvious that the optoelectronic reciprocity theorem holds for the various solar cells that exist. In this study, we report the results of qualitative and quantitative confirmation of the validity of the optoelectronic reciprocity theorem for high-efficiency ${\mathrm{Cu}\mathrm{In}}_{1\ensuremath{-}x}{\mathrm{Ga}}_{x}{\mathrm{Se}}_{2}$ (CIGS) solar cells fabricated by us. The results confirm that our CIGS solar cells qualitatively and quantitatively satisfy the optoelectronic reciprocity theorem within the limits of measurement uncertainty. Also, we experimentally confirm that the value of the diode ideality factor for the applied voltage dependence of the EL emission intensity is exactly unity when the emission mechanism is the band-edge emission due to the direct recombination of electron-hole pairs. Finally, the importance of the ${\ensuremath{\eta}}_{\mathrm{ext}}$ for improving solar cell efficiency is explained.

EXPERIMENTAL ESTIMATE OF EROSION MECHANISM AT THE EARLY STAGE OF GULLY FORMATION<a href="#FN1"><sup>1</sup></a>

The article presents results of experiment and its theoretical justification aimed to study the mechanism and intensity of the early stage of gully head formation. The experiment was carried out using the jet installation that allows to change the angle of the water stream from 0.5 to 90° with the flow velocity of up to 6 m/s. The flow angle was changed with a 10° step, while the flow velocity was maintained in the range of 1.01–1.04 m/s. The intensity of soil erosion positively correlates with the flow angles (angles of attack) in the range from zero up to 40°. When the angle was increased to 50–90°, the intensity continuously declined. The lowest absolute values of erosion intensity were observed when the water flow was normal to the soil surface. There are two main reasons why the intensity of soil erosion changes with changing angle of stream flow; the first is hydraulic, the second is hydro-mechanical. The former determines weakening and destruction of inter-aggregate bonds by the water penetrating into the soil; the latter – by the combined vectors of forces of hydrodynamic head and forces keeping the particle (aggregate) in place. The experiment showed that the maximum impact of water jet on a separate soil particle occur at angle of 41°. The flow in a gully happens occasionally and the results obtained should be attributed to the early stage of erosion: the stage before formation of a so called gully headcut.

DIAGNOSTICS OF PLASMA OF ELECTRIC ARC DISCHARGE BETWEEN ASYMMETRIC SINGLE-COMPONENT Cu AND Ni ELECTRODES

In this work, the radial distributions of parameters of plasma with copper and nickel vapours admixtures in positive column of electric arc discharge were investigated by optical emission spectroscopy. The plasma temperature was determined by the Boltzmann plot technique on the basis of absolute values of radiation intensity of both copper and nickel atomic spectral lines. Concentrations of both kinds of metal atoms of electrode origin were determined by the method of absolute intensities of the corresponding spectral lines of radiation of such plasma.

INVESTIGATION OF THERMAL PLASMA OF ARC DISCHARGE BETWEEN NOVEL COMPOSITE Cu-W MATERIALS

In this work, the plasma emission of electric arc discharges between pairs of composite Cu-W electrodes was investigated by optical emission spectroscopy. Electrodes manufactured of Cu-W 50 vol.% composite materials by shock sintering technology at temperatures of 750, 850, 950, and 1050°C were used. The radial distributions of plasma temperature were determined by Boltzmann plot technique on the basis of the absolute values of intensity of both copper and tungsten spectral lines. The concentration of metal atoms of electrode origin (copper and tungsten) in the positive plasma column of electric arc discharges between studied electrodes manufactured of composite Cu-W materials was determined by the method of absolute intensities. The intensity of erosion of individual components of composite materials is estimated in an indirect way by comparing the radial distributions of atoms of materials of electrode origin for each type of the investigated arc discharge.

Monte Carlo simulation of handheld probes to detect non-invasive ductal carcinoma from diffuse optical reflectance signals

To identify the malignancy in human breast, hand-held optical probes are simulated using the Monte Carlo method. These devices were used to scan different tissue equivalent numerical breast phantoms to detect the embedded cancerous tissues in them. The phantoms were simulated with glandular tissues embedded with ductal carcinoma of size 5 mm and 2 mm diameter at various depths. Two optical probes namely dual side detector (DSD) probe and a single side detector (SSD) probe are designed through which one million light photons of wavelengths 600 nm and 800 nm respectively were passed into the numerical phantoms. The photons that were backscattered from the phantoms were received by the detectors in both probes. They were measured as signals and both probes were able to detect the presence of the embedded cancerous tissues at different depths. The results indicate that the probes with a light source at 800 nm could detect deep-seated inhomogeneities. The absolute value of Peak Intensity (|PI|) and Full Width at Half Maximum (FWHM) would be indicative of their location and approximate size of the embedded tissues. The |PI| decreases with the size and depth of the embedded tissue, and the FWHM increases with depth. The results show that the designed probes are capable of detecting small variations in tissues.

Selectively probing ferric ions in aqueous environments using protonated and neutral forms of 7-azaindole as a multiparametric chemosensor.

7-azaindole (7AI) dimer is a model molecule for DNA study and understanding the mutagenic behavior based on the excited-state proton transfer process in hydrogen-bonded networks. The neutral and protonated forms of 7AI monomer with significant fluorescence (FL) intensity fit the fluorescent sensor strategy to recognize selective metal ions. Out of several metal ions (Fe3+, Al3+, Fe2+, Pb2+, Ba2+, Ni2+, Zn2+, Mg2+, Ca2+, Cu2+, Hg2+ and Cd2+), the absorption, fluorescence and fluorescence lifetime of 7AI in the aqueous medium are selectively sensitive to the ferric (Fe3+) ions. The absolute value of absorption intensity increases linearly with concentration of a particular metal ions. FL intensity of both the forms of 7AI decreases gradually with Fe3+ ions and trails the linear Stern-Volmer relation. The formation of non-fluorescent complexes was confirmed with Benesi-Hildebrand and Job plots, along with FL and FL decays. The FL lifetime of the protonated form of 7AI, which is 0.83 ± 0.01ns, is nearly constant with Fe3+ ions concentrations, confirming the static quenching mechanism. The limit of detection (LoD) of Fe3+ ions over the long range of 16-363µM for the neutral and protonated forms of 7AI is 0.46 ± 0.02 and 0.49 ± 0.02µM, respectively, estimated using FL spectra. Additionally, the linear plot of absorbance with Fe3+ ions of both the forms of 7AI can also act as a calibration curve with very close LoDs, as obtained by FL spectra. Thus, the multi-parameters-based probe for detecting the Fe3+ ions over long-range in real aqueous environments with operational, high sensitivity, fast response (< 5s), and good selectivity (over 12 metal ions) is undoubtedly a superior approach over other methods.

Accurate absolute frequency measurement of the S(2) transition in the fundamental band of H2 near 2.03 μm.

A series of spectra of the quadrupolar electric S(2) transition of H2 in the 1-0 band near 4917 cm-1 has been recorded at seven pressure values between 2 and 100 Torr. The comb-referenced cavity ring down spectroscopy (CR-CRDS) technique was used for the recording of this very weak transition. The accuracy of the spectrum frequency axis is achieved by linking the CRDS setup to an optical frequency comb referenced to a GPS-referenced 10 MHz rubidium clock. Applying a multi-spectrum fit procedure to the seven averaged spectra with a quadratic speed dependence Nelkin-Ghatak profile, the transition frequency is determined (ν0 = 147 408 142 357 kHz) with an uncertainty of 150 kHz (∼1 × 10-9 in relative). This represents the smallest uncertainty achieved so far for a transition in the fundamental band of H2. The experimental frequency reported in this work is 1.53 MHz higher than the best-to-date theoretical value. This difference represents 1.5 times the 1σ-uncertainty (about 1 MHz) of the calculated frequency. The measurements also allow for the determination of the absolute intensity value of the S(2) line which shows an agreement with the ab initio value at the per mil level. In addition, the cross section of the collision induced absorption (CIA) underlying the S(2) line is accurately retrieved from the quadratic pressure dependence of the baseline level of the recorded spectra.

Outcomes of right lobe donors with BMI≥30 for living donor liver transplantation.

Donor BMI above 30 is generally considered contraindication for donor hepatectomy. We compared the donor outcomes based on BMI threshold and weight loss. All potential donors were identified and data were collected retrospectively. Steatosis was assessed based on liver-spleen Hounsfield unit difference and absolute liver intensity values. We compared BMI≥30 (n=53) and BMI<30 (n=64) donor outcomes. Donors with weight loss (WL) prior to surgery were also analyzed separately. Complications were graded by Clavien-Dindo classification. All donors underwent open right donor hepatectomy. There was no difference between BMI≥30 and<30 groups except female predominance in BMI≥30 group (P=.006). Both groups had similar rates of complication rates in all categories, similar remnant volume, operative time, length of stay and similar postoperative liver function recovery (all P>.05). On the other hand, donors with WL were more commonly male, had smaller graft size, and higher biliary complications rates compared to no-WL donors (all P<.05). Multivariate binary logistics regression analysis revealed no association between BMI or WL and outcomes. We demonstrate that donors with BMI≥30 have similar outcomes compared to BMI<30 donors with our defined selection criterion, therefore BMI≥30 is not an absolute contraindication to donate right liver, provided that there is no significant steatosis and remnant liver is satisfactory. For potential overweight donors, WL down to BMI<30 is a reasonable target. Higher biliary complication rates after WL should be investigated further.

Degree of oxidation of sonicated soybean oil using various sonication process parameters

SummaryThis research aimed to examine the effect of high‐intensity ultrasound (HIU) on the oxidation of soybean oil (SBO). Samples (5, 100, and 250 g) were sonicated at 25 °C using various sonication conditions: power level (settings 1, 5, and 9), tip size (12.7, 3.2, and 2 mm), and duration (5, 10, and 60 s). After sonication, the degree of oxidation of samples (sonicated and non‐sonicated SBO) were analysed using peroxide value (PV), oil stability index (OSI), and volatile compounds. Sonication was applied to obtain a range of absolute power (0–123.5 W), power density (0–14.2 W cm−3), and power intensity (0–1,120 W cm−2) values. The highest power density and power intensity were obtained with the highest HIU setting with the 3.2 mm tip. The highest power was obtained when HIU was applied using a 12.7 mm tip and setting 9 in 250 g of sample. No significant difference (P &gt; 0.05) was observed in PV (0.20 ± 0.01 mEq kg−1) nor OSI (10.05 ± 0.04 h), among the various sonication conditions tested. In addition, no differences were observed in the volatile compounds obtained. These results show that HIU can be used under mild sonication conditions such as the ones needed to change the physical properties of lipids without causing oxidative deterioration.

Molecular dynamics study of three amino acids as corrosion inhibitor for copper in hydrochloric acid solution.

Molecular dynamics (MD) simulation is used to study the corrosion inhibition mechanism of cysteine (Cys), glutamic (Glu) and glycine (Gly) for copper in hydrochloric acid solution. The adsorption energy and radial distribution function results show that all three amino acids can spontaneously adsorb on Cu (111) surface by chemical adsorption. The absolute value of adsorption energy and intensity is Cys > Glu > Gly. The diffusion coefficient and relative concentration curve show that all the three amino acids can inhibit the diffusion and aggregation ability of corrosion particles, so the three amino acids not only can slow down the aggregation of corrosive particles, but also effectively repel corrosive particles to protect the substrate. The inhibition ability obtained by the MD simulation shows the trend of Cys > Glu > Gly, which is consistent with the experimental results. The inhibition efficiency is determined by both the adsorption strength on the substrate surface and inhibition ability for the diffusion and aggregation ability of corrosion particles.

Measurements of the absolute values of the radiation intensity in the wavelength range of 6.6-32 nm of stainless steel targets with pulsed laser excitation

The paper presents experimental data on the absolute values of the radiation intensity in the wavelength range of 6.6-32 nm for a stainless steel target excited by a Nd: YAG laser with parameters λ=1064 nm, Epulse=0.45 J, tau=4 ns, ν=10 Hz. The results are of interest for various applications using laboratory laser-plasma sources of soft X-ray and extreme ultraviolet radiation. Keywords: extreme ultraviolet radiation, emission spectrum, laser spark, multilayer X-ray mirror.

Magnetic storm and term‐day observations at the Prague observatory Clementinum in the mid‐19th century

AbstractMagnetic observations at the Clementinum Observatory were started in July 1839 and data up to 1917 were published in yearbooks. In addition to regular daily observations with a typical 2‐hr time step, two categories of data with a higher cadence were provided in the first decade. The first category captures 73 magnetic storms with their magnitude being of at least a moderate level. The second category is the dense observations during the days that had been agreed for joint measurements by the observatories organized in the Göttingen Magnetic Union (GMU), these measurements being known as term‐day observations. Whereas four terms per year were set by GMU, many observatories agreed to carry out additional observations in the eight remaining months. The term‐day observations also continued being performed for several years after the end of the GMU activities in 1841. Data of 120 term days from January 1840 to December 1849 were published. The declination was observed using the magnetic compass principle, while a bifilar apparatus was used to measure the horizontal intensity. When converting the data to the physical units of the SI, we have achieved the consistency of these high cadence data with previously published regular hourly observations of the geomagnetic field. This requirement was also met by considering the temperature dependence of measurements by the bifilar apparatus in determining the absolute values of horizontal intensity. Revealing the historical observations of the geomagnetic field can serve as a valuable material for studying the space weather in the past and may also contribute to the refinement of global field modelling.

The temperature state of a plane dielectric layer at constant voltage and fixed temperature of one of the surfaces of this layer

The paper formulates the nonlinear problem of steady‐state heat conduction at the constant electric potential difference on the surfaces of a plane dielectric layer with the temperature‐dependent heat conduction coefficient and electrical resistivity. A fixed temperature value is set on one of the layer surfaces, and the convective heat exchange with the ambient medium occurs on the opposite surface. The formulation of the problem is transformed to integral ratios, which allows the calculation of the temperature distribution over the layer thickness, governed by the monotonic and nonmonotonic functions. The quantitative assay of the temperature state of a layer of a polymer dielectric made of amorphous polycarbonate is given as an example and the analysis of nonuniformity of the absolute value of electric field intensity over the thickness of this layer.

Magnetic Surveys With Unmanned Aerial Systems: Software for Assessing and Comparing the Accuracy of Different Sensor Systems, Suspension Designs and Compensation Methods

AbstractA typical problem for magnetic surveys with small Unmanned Aerial Systems (sUAS) is the heading error caused by undesired magnetic signals that originate from the aircraft. This can be addressed by suspending the magnetometers on sufficiently long tethers. However, tethered payloads require skilled pilots and are difficult to fly safely. Alternatively, the magnetometer can be fixed on the aircraft. In this case, aircraft magnetic signals are removed from the recordings with a process referred to as magnetic compensation, which requires parameters estimated from calibration flights flown in an area with magnetically low‐gradients prior to the survey. We present open‐source software fully written in Python to process data and compute compensations for two fundamentally different magnetometer systems (scalar and vector). We used the software to compare the precision of two commercially available systems by flying dense grid patterns over a 135 × 150 m area using different suspension configurations. The accuracy of the magnetic recordings is assessed using both standard deviations of the calibration pattern and tie‐line cross‐over differences from the survey. After compensation, the vector magnetometer provides the lowest heading error. However, the magnetic field intensity recovered with this system is relative and needs to be adjusted with absolute data if absolute intensity values are needed. Overall, the highest accuracy of all suspension configurations tested was obtained by fixing the magnetometer 0.5 m below the sUAS onto a self‐built carbon‐fiber frame, which also offered greater stability and allowed fully autonomous flights in a wide range of conditions.

Vortex-induced vibration response of a cactus-inspired cylinder near a stationary wall

Vortex-induced vibration (VIV) responses of a cactus-inspired cylinder near a stationary wall are numerically studied, and the effects of the height ratios (Ks/D, Ks is the height) of the cactus-inspired structure and the stationary wall on VIV response are discussed in detail. The VIV response region is usually divided into four sub-regions, namely, the initial branch (region I), the upper branch (region II), the lower branch (region III), and the desynchronization branch (region IV). The Reynolds number at which the maximum vibration amplitude occurs for the cylinder near the stationary wall is lower than that of a free-standing cylinder. The Reynolds number at which the maximum amplitude occurs decreases with an increase in the height ratio of the structure. Due to effects of the stationary wall, the critical reduced velocity at which the vortex phase jump occurs decreases. With an increase in the height ratio of the structure, the critical reduced velocity at which the vortex phase jump occurs gradually decreases. Vortex shedding is seen from the stationary wall, and the vortex moves clockwise. This vortex can weaken vortex shedding from the cylinder. Due to the large-amplitude motion, the vortex shedding from the cylinder is coupled with the stationary wall, which promotes the separation of the wall boundary layer. With an increase in the height ratio of the structure, the absolute value of vortex intensity gradually decreases, and the distance between the vortex-shedding position and the cylinder gradually increases. Therefore, the cactus-inspired structure not only changes the form of the wake vortex, but also changes the strength of the wake vortex.

Refining geomagnetic field intensity changes in Europe between 200 CE and 1800 CE. New data from the Mediterranean region

Absolute past geomagnetic intensity values can mainly be recovered by fired archaeological materials and volcanic rocks. Here, we present 10 new archeointensities from the Mediterranean region that help to better constrain geomagnetic field intensity changes in Europe over the last two millennia. The new archeointensity results were obtained from the Thellier classical method including thermoremanent magnetization (pTRM) checks and both the TRM anisotropy and cooling rate corrections and were derived from at least three specimens. The new data presented, together with a selection of previous archeointensities satisfying a set of quality criteria, confirm the presence of several intensity maxima in Europe over the last 2000 years. In particular, the new archeointensities allow to better define the starting point of the double-oscillation feature that occurred in Europe during the second half of the first millennium CE, and reinforce the existence of a relative maximum at the end of the 14th century - beginning of the 15th century in Western Europe. From selected European archeointensities two new paleosecular variation curves are constructed for Western and Eastern Europe using temporal cubic b-splines in a bootstrap approach. The obtained curves suggest that the occurrence of the intensity maxima is characterized by a period of about 300 ± 50 years. In addition, our results suggest that the maxima do not occur simultaneously in Western and Eastern Europe, pointing out an intensity eastward drift with a mean lag-time of about 100 years.