Increase In Brightness Research Articles

ASASSN-21co: A Detached Eclipsing Binary with an 11.9 yr Period

Abstract We use ASAS V-band and ASAS-SN g-band observations to model the long-period detached eclipsing binary ASASSN-21co. ASAS observations show an eclipse of depth V ∼ 0.6 mag in 2009 April. ASAS-SN g-band observations from 2021 March show an eclipse of similar duration and depth, suggesting an orbital period of 11.9 yr. We combine the g-band observations with additional BVRI photometry taken during the eclipse to model the eclipse using PHOEBE. We find that the system is best described by two M giants with a ratio of secondary radius to primary radius of ∼0.61. Optical spectra taken during the eclipse are consistent with at least one component of the binary being an M giant, and we find no temporal changes in the spectral features. The eclipse itself is asymmetric, showing an increase in brightness near mid-eclipse, likely due to rotational variability that is too low amplitude to be observed out-of-eclipse.

Feasibility Study of Microwave‐Assisted Biodiesel Production from Vegetable Oil Refinery Waste

AbstractVegetable oil refinery waste containing acid oil is used as an inexpensive feedstock for producing biodiesel by microwave‐assisted esterification (MAE) method. Effects of some main variables such as free fatty acid:methanol molar ratio (1:1, 1:5, and 1:10), reaction time (5, 30, and 60 min), and catalyst concentration (1%, 2%, and 3%) on physicochemical properties of produced biodiesel are investigated. Optimum reaction conditions of MAE are free fatty acid:methanol molar ratio of 1:10, reaction time of 60 min, and a catalyst concentration of 3%, while having 95.79% conversion yield. By increasing the conversion yield of the biodiesel, density and color brightness increase, while viscosity and refractive index decrease. There are no significant differences between physicochemical and heating properties of biodiesel produced by MAE and magnetic stirrer esterification (MSE) methods. Meanwhile, energy consumption of MAE method is almost four times lower than that of MSE. MAE as a promising alternative to the conventional esterification method can be considered as an energy‐efficient method for producing biodiesel from inexpensive vegetable oil refinery waste.Practical applications: Acid oil is an inexpensive by‐product of alkali refining in vegetable oil plants that would pollute the environment if not rendered safely. In this study, MAE is used to convert acid oil to biodiesel as a practical process for bringing alkali refining waste into production cycle. Acid oil can provide a reduction in the cost of biodiesel production. In addition, application of energy‐efficient MAE method can facilitate the economical production of biodiesel.

Investigating the effect of WO3 on the crystallization behavior of SiO2–B2O3 – Al2O3–Na2O – CaO–ZnO high VIS-NIR reflecting glazes

White glass enamels with high solar reflectance and containing different WO3 concentrations have been prepared and characterized with regard to their optical, mechanical and microstructural characteristics. Upon addition of WO3 to a glass containing SiO2, B2O3, Al2O3, Na2O, CaO, and ZnO, the crystallization of scheelite follows a crystallization mechanism of bulk type where scheelite grows in one-dimension in a patterned morphology dominated by the heating rate and the concentration of WO3. Octahedral bipyramids and arrow-like crystals appeared in enamels containing WO3 concentration above 6%. The presence of scheelite crystals with different orientations also leads to slight variations in hardness and Young modulus thus obtaining Hv values between 8 and 8.8 GPa and E values between 72 and 83 GPa. Similarly, the optical properties such as whiteness, brightness and solar reflectance increase with the presence of scheelite, and the highest solar reflectance occurs for the enamel containing arrow-like and bipyramidal crystals.

An infrared study of Galactic OH/IR stars – III. Variability properties of the Arecibo sample

ABSTRACT We present the results of a near-infrared (NIR) monitoring programme carried out between 1999 and 2005 to determine the variability properties of the ‘Arecibo sample of OH/IR stars’. The sample consists of 385 IRAS-selected Asymptotic Giant Branch (AGB) candidates, for which their O-rich chemistry has been proven by the detection of 1612 MHz OH maser emission. The monitoring data were complemented by data collected from public optical and NIR surveys. We fitted the light curves obtained in the optical and NIR bands with a model using an asymmetric cosine function, and derived a period for 345 sources (∼90 per cent of the sample). Based on their variability properties, most of the Arecibo sources are classified as long-period large-amplitude variable (LPLAV) stars, 4 per cent as (candidate) post-AGB stars, and 3 per cent remain unclassified although they are likely post-AGB stars or highly obscured AGB stars. The period distribution of the LPLAVs peaks at ∼400 d, with periods between 300 and 800 d for most of the sources, and has a long tail up to ∼2100 d. Typically, the amplitudes are between 1 and 3 mag in the NIR and between 2 and 6 mag in the optical. We find correlations between periods and amplitudes, with larger amplitudes associated with longer periods, as well as between the period and the infrared colours, with the longer periods linked to the redder sources. Among the post-AGB stars, the light curve of IRAS 19566+3423 was exceptional, showing a large systematic increase (>0.4 mag yr−1) in K-band brightness over 7 yr.

Versatile, high brightness, cryogenic photoinjector electron source

Since the introduction of the radio-frequency (rf) photoinjector electron source over thirty years ago, peak performance demands have dictated the use of high accelerating electric fields. With recent strong advances in obtainable field values, attendant increases in beam brightness are expected to be dramatic. In this article, we examine the implementation of very high gradient acceleration in a high frequency, cryogenic rf photoinjector. We discuss in detail the effects of introducing, through an optimized rf cavity shape, rich spatial harmonic content in the accelerating modes in this device. Higher spatial harmonics give useful, enhanced linear focusing effects, as well as potentially deleterious nonlinear transverse forces. They also serve to strongly increase the ratio of average accelerating field to peak surface field, thus aiding in managing power and dark current-related challenges. We investigate two scenarios which are aimed at unique exploitation of the capabilities of this source. First, we investigate the obtaining of extremely high six-dimensional brightness for advanced free-electron laser applications. We also examine the use of a magnetized photocathode in the device for producing unprecedented low asymmetric emittance, high-current electron beams that reach linear collider-compatible performance. As both of the scenarios demand an advanced, compact solenoid design, we describe a novel cryogenic solenoid system. With the high field rf and magnetostatic structures introduced, we analyze the collective beam dynamics in these systems through theory and multi-particle simulations, including a particular emphasis on granularity effects associated with microscopic Coulomb interactions.

THE EFFECT OF AVERRHOA BILIMBI L (BELIMBING WULUH) GEL EXTRACT ON INCREASING THE DEGREE OF THE TEETH BRIGHTNESS (IN VIVO)

Discoloration (extrinsic and intrinsic) reduce the beauty of someone's appearance and confidence. Discoloration affected the increased aesthetic treatment needs in dentistry. Discoloration can be treated by teeth whitening procedures. Teeth whitening can be done with dental bleaching from the application of chemicals on the surface of the teeth. However, dental bleaching has side effects such as reduce the amount of calcium, phosphate and fluoride in tooth enamel, reduce enamel hardness, enamel surface roughness, and dental hypersensitivity. Belimbing wuluh is one of the herbal ingredients to minimise the risk; it contains oxalic acid, a natural peroxide compound. This study purposed to determine the effect of belimbing wuluh gel extract in increasing the degree of teeth brightness colour by in vivo in rabbits. This study used an experimental analytic method with 27 rabbits' incisors, divided into three groups: 50% belimbing wuluh gel, 40% oxalic acid gel, and negative control group. Rabbits' incisors were previously coated in a transparent varnish on the specified area. Teeth bleaching is done for 4 hours in 14 days. Colour measurements used camera and ring-light, which MATLAB will convert. The data were analysed statistically with One way ANOVA followed by a post-hoc NSK test (p <0.05). The result showed that belimbing wuluh gel extract caused an increase in the teeth colour's brightness (p = 0.0030). So, it can be concluded that belimbing wuluh gel extract affects increasing the degree of teeth brightness.

Morphological classification of compact and extended radio galaxies using convolutional neural networks and data augmentation techniques

ABSTRACT Machine-learning techniques have been increasingly used in astronomical applications and have proven to successfully classify objects in image data with high accuracy. The current work uses archival data from the Faint Images of the Radio Sky at Twenty Centimeters (FIRST) to classify radio galaxies into four classes: Fanaroff–Riley Class I (FRI), Fanaroff–Riley Class II (FRII), Bent-Tailed (BENT), and Compact (COMPT). The model presented in this work is based on Convolutional Neural Networks (CNNs). The proposed architecture comprises three parallel blocks of convolutional layers combined and processed for final classification by two feed-forward layers. Our model classified selected classes of radio galaxy sources on an independent testing subset with an average of 96 per cent for precision, recall, and F1 score. The best selected augmentation techniques were rotations, horizontal or vertical flips, and increase of brightness. Shifts, zoom, and decrease of brightness worsened the performance of the model. The current results show that model developed in this work is able to identify different morphological classes of radio galaxies with a high efficiency and performance.

43‐3: Laser Assisted LED for High Output Automotive DMD Headlight

Most of ADB headlight engines are designed using blue LED or laser light sources for the exciting the phosphor conversion layer producing white light output. The phosphor conversion layers have been fabricated by silicone‐based phosphor, glass‐based phosphor, ceramic‐based phosphor, and single crystal‐based phosphor. Among these different phosphor materials, the single crystal phosphor (SCP) exhibits excellent thermal stability, better conversion efficiency, and high transparency to yellow light, but the required high‐temperature fabrication process, has been an impediment for widespread commercial production. Recently, the issues of higher fabrication temperature of the SCP have been overcome by using a novel design of single crystal growth to produce SCP with higher yield and better uniformity. In this study, the ADB headlight consists of a well‐developed, high efficiency, automotive qualified white LED, a TI digit mirror device (DMD), a projection lens, and a Laser‐Assist™ LED system using two laser diodes and a SCP plate. The SCP plates are fabricated by Czochralski technology at the high temperature of 1,940°C. Using the laser for the Laser‐Assist™ process, a 50% increase in the LED is obtained. This increase in output enables the increase in FOV and brightness of the ADB headlight, which results in significant improvement of the visibility and the illumination distance. The proposed advanced ADB headlight with ultra‐reliable SCP and Laser‐Assist™ LED system will become one of the most promising ADB headlight candidates for use in the next‐generation autonomous vehicle applications.

47‐4: Student Paper: Ambient Light and Human Vision Effects on High‐Dynamic‐Range Displays

Ambient light and human vision effects on high‐dynamic‐range mini‐LED backlit LCDs (mLCDs) and OLED displays are investigated. Subjective visual experiment is also conducted to validate our analyses. As the ambient light brightness increases, the required local dimming zones for mLCDs to achieve comparable visual quality with OLED displays decreases dramatically.

A broad-band planar-microcavity quantum-dot single-photon source with a solid immersion lens

The integration of single quantum dots (QDs) into a planar Fabry–Pérot microcavity has been established as a direct and viable approach to vertically steer photons emitted from the quantum emitters, resulting in a strong increase in the source brightness, which becomes particularly evident when a lens with a low numerical aperture is used. However, the spectral bandwidth of QD–microcavity structures is limited and determined by their intrinsic quality factor; these structures are, thus, not ideal for the extraction of entangled photon pairs or for studies of exciton dynamics. We have found that, when a deterministic low-index solid immersion lens is placed on top of the QD in a QD–microcavity structure, the structure exhibits an enhancement in the bandwidth to 27 nm and a source brightness of 23%. The solid immersion lens is deterministically fabricated via two-photon absorption and can be remade several times without perturbing the QD, ensuring that the QD's intrinsic properties are preserved and ensuring its long-term reliability.

Light pollution in India: appraisal of artificial night sky brightness of cities

The spectacular progress of lighting equipment in recent decades has resulted in an enormous increase in outdoor lights and night-sky brightness which is the most noticeable effects of light pollution has increased rapidly in many countries. Any pollution is a consequence of urbanization forces, which correspond to a significant threat to human health and the environment. Despite the increasing awareness and interest, there is a need for quantification of light pollution at a national and local scale. In developing nations like India, the supremacy of basic issues often undermines the new-found urban problems that have the potential of affecting the environment at a larger scale. Light pollution is one such predicament that needs a response. This study intends to mark the fundamental concept of light pollution, its impacts, and develop an atlas of the ten most populated Indian cities following the magnitude of their brightness computed using high-resolution satellite data. It also attempts to relate the degree of brightness of these cities with safety in cities, which is the primary purpose of lighting at night, also taking into account various factors that may impact the night time lighting and safety in urban areas. According to the study, street lights installed in a city exhibit a considerable correlation with the brightness levels of the cities, which may point towards a significant source of light pollution in cities. The paper concludes with a discussion of some best practices in the context of light pollution and the scope for further investigation.

Efeito da extração alcalina na redução do número Kappa no branqueamento ECF

The acid hydrolysis stage (A HT ) used in bleaching sequences of pulp, has as its main objective, the degradation of hexenuronic acids which are present in the pulp and can affect its brightness, reversal of brightness, among others. Despite the benefit of using the acid hydrolysis stage, the pH of this stage is not the most adequate, but when it comes to the degradation of lignin, it is more reactive in alkaline medium. Therefore, the present work sought to study an improvement in the bleaching process by the addition of an alkaline extraction stage after A HT stage, obtaining the best possible use of the chlorine dioxide stage. In this study, oxygen-delignified Kraft pulp from eucalyptus was used. Different ECF (Elemental Chlorine Free) bleaching sequences were performed in the pulp: D 0 (E+P)D 1 , A HT D 0 (E+P)D 1 , A HT /ED 0 (E+P)D 1 and A HT ED 0 (E+P)D 1 .As a result, the inclusion of a simple alkaline stage after the acid hydrolysis indicate a positive effect on the bleaching sequence, with a significant reduction in the consumption of chlorine dioxide. The inclusion of simple alkaline extraction also allowed the reduction of the kappa number and increased brightness, with a reduction of 0.3 points in the average Kappa number and a 1.3% ISO increase in brightness, analyzed after alkaline extraction with hydrogen peroxide of the sequence A HT /ED 0 (E+P)D 1 when compared to the one without simple alkaline extraction.

Efficient G protein coupling is not required for agonist-mediated internalization and membrane reorganization of the adenosine A3 receptor.

Organization of G protein‐coupled receptors at the plasma membrane has been the focus of much recent attention. Advanced microscopy techniques have shown that these receptors can be localized to discrete microdomains and reorganization upon ligand activation is crucial in orchestrating their signaling. Here, we have compared the membrane organization and downstream signaling of a mutant (R108A, R3.50A) of the adenosine A3 receptor (A3AR) to that of the wild‐type receptor. Fluorescence Correlation Spectroscopy (FCS) studies with a fluorescent agonist (ABEA‐X‐BY630) demonstrated that both wild‐type and mutant receptors bind agonist with high affinity but in subsequent downstream signaling assays the R108A mutation abolished agonist‐mediated inhibition of cAMP production and ERK phosphorylation. In further FCS studies, both A3AR and A3AR R108A underwent similar agonist‐induced increases in receptor density and molecular brightness which were accompanied by a decrease in membrane diffusion after agonist treatment. Using bimolecular fluorescence complementation, experiments showed that the R108A mutant retained the ability to recruit β‐arrestin and these receptor/arrestin complexes displayed similar membrane diffusion and organization to that observed with wild‐type receptors. These data demonstrate that effective G protein signaling is not a prerequisite for agonist‐stimulated β‐arrestin recruitment and membrane reorganization of the A3AR.

Midsummer Atmospheric Changes in Saturn’s Northern Hemisphere from the Hubble OPAL Program

Abstract Using the Hubble Space Telescope, Saturn was observed in 2018, 2019, and 2020, just after the northern hemisphere summer solstice. Analysis of multispectral imaging data reveals three years of cloud changes associated with a 70° N storm that began in 2018. Additionally, there is an increase in equatorial brightness and perhaps haze optical depth at 0° to 7° N. There are small midsummer changes at the north pole, with a thin blue feature near the polar hexagon’s outer edge disappearing between 2019 and 2020 and increasingly reddish polar haze. Zonal winds at most latitudes remain close to values obtained by the Cassini mission with a slight increase of winds in the equatorial zone. Yearly cloud changes, while noticeable, are small compared with the changes observed between the Voyager (northern spring) and Cassini (southern summer to northern spring) eras, but further observations will provide a longer baseline for comparison.

Postvolcanic Aerosols: Measurements of Altitude and Particle Sizes with Twilight-Sky Polarimetry

The intensity and polarization of the twilight-sky background were measured during the epoch of “purple lights” after the Raikoke volcanic eruption in the summer of 2019. The increase in brightness paired with the decrease in polarization was registered, and the changes were especially noticeable in the dusk segment. The altitude distribution of aerosol particles and their mean size were found with previously developed techniques. The median radius of the lognormal distribution (0.11 μm) is typical of the background conditions or weak eruptions; however, the aerosols were mostly concentrated in the upper troposphere and near the tropopause rather than in the stratosphere. From comparison with satellite data obtained almost a decade ago after similar eruptions (like those of the Kasatochi volcano and others), it has been shown that the properties of their aerosols are similar, which confirms that the purple light phenomenon observed in 2019 was of volcanic origin.

Geometric constraints of molecular self-assembly of normal alkanes on graphite

An abrupt increase of CH3-groups brightness as well as CH2-groups modulation along alkyl skeleton were observed in scanning tunneling microscopy (STM) images of n-alkanes monolayers on graphite. Analysis of STM-patterns demonstrates that both effects strongly depend on deformations of molecules and scanning conditions. We have observed that due to deformations, the monolayer is going to be compressed, thus methylene units protrude away from the surface forming a corrugated structure. Moreover, the distance between adjacent lamellae narrows, leading to the absence of furrows and, in particular, to a significant increasing of tunneling current from peripheral groups. The whole monolayer has been conserving its anomalous brightness for a few hours. Moreover, when the scanning conditions are changed, the monolayer could undergo an instantaneous reordering from the structure with increased brightness to the uniform one.

ДОСЛІДЖЕННЯ ЗВ'ЯЗКУ МІЖ БОМБОЮ ЕЛЛЕРМАНА І Hα-СЬОРЖАМИ

Based on the analysis of spectral observations in the H α line of a site of the active region NOAA 11024, where the Ellerman bomb appeared and developed and during our observations various types of chromospheric matter ejections were formed, a study of the connection between these small-scale elements of solar activity has been carried out. Spectral data with high spatial and temporal resolution were obtained with the French–Italian 90-cm vacuum telescope THEMIS (Tenerife, Spain) on July 4, 2009. The observation time was 20 minutes. The AR site under investigation was in the region of a new magnetic flux emerging at this time. A site with high activity was select – it was pore on it, the Ellerman bomb (EB) was developing and many chromospheric ejections (surge) arose. The features of the formation and development of surges that appeared near the pore, which was at a distance of 7.2 Mm from the Ellerman bomb, were studied. Changes in the line-of-sight velocity (Vlos) and the direction of chromospheric matter motion in Hα-surges are analyzed. During our observations, the maximum plasma velocity upward reached – 95 km/s, and downward – 80 km/s. In the upper part of the magnetic loops, the Vlos of the plasma varied between – 20 km/s and 15 km/s. The velocity values in the area without active formations did not exceed ± 2 km/s. The distribution of velocities within Hα-surges showed that they mainly had a fine structure – they consisted of several jets. In most cases, upward and downward plasma flows occurred simultaneously with an increase in the EB brightness. Our study showed that during a sharp increase in the brightness of the EB, the chromospheric mater velocities in the surges increased, the direction of its movement changed, new surges appeared, which indicates a connection of the Hα-surges that developed near the pore with the Ellerman bomb, as well indicates that all these processes were the result of magnetic reconnections caused by the emergence of a new serpentine magnetic flux and its interaction with the pre-existing magnetic field.

Long-term optical photometric monitoring of the FUor star V900 Mon

We present results from photometric monitoring of V900 Mon, one of the newly discovered and still under-studied object from the FU Orionis type. The FUor phenomenon is very rarely observed, but it is essential for stellar evolution. Since we only know about twenty stars of this type, the study of each new object is very important for our knowledge. Our data were obtained in optical spectral region with the BVRI Johnson-Cousins set of filters during the period from September 2011 to April 2021. In order to follow the photometric history of the object, we measured its stellar magnitudes on available plates from the Mikulski Archive for Space Telescopes. The collected archival data suggest that the rise in brightness of V900 Mon began after January 1989 and the outburst goes on so far. In November 2009, when the outburst was registered, the star had already reached the level of brightness close to the current one. Our observations indicate that during the period 2011-2017 the stellar magnitude increased gradually in each pass band. The observed amplitude of the outburst is about 4 magnitudes (R). During the last three years, the increase in brightness has stopped and there has even been a slight decline. The comparison of light curves of the known FUor objects shows that they are very diverse and are rarely repeated. However, the photometric data we have so far show that V900 Mon's light curve is somewhat similar to those of V1515 Cyg and V733 Cep.

Bleach enhancement of mixed wood pulp by mixture of thermo-alkali-stable xylanase and mannanase derived through co-culturing of Alkalophilic Bacillus sp. NG-27 and Bacillus nealsonii PN-11

The Application of a combination of enzymes is the best alternative to reduce the use of chemicals in the paper industry. Bacillus sp. NG-27 and Bacillus nealsonii PN-11 are known to produce thermoalkali stable xylanse (X) and mannanase (M) respectively having potential for pulp biobleaching. The Present study, reports the production of a mixture of X + M by co-culturing of strains in SSF and standardizing its application for pulp biobleaching. Production of enzymes by co-cultivation in SSF was optimized by statistical methods. Substantial increase in the yield of enzymes; 3.61 fold of xylanase and 37.71 fold of mannanase was achieved. Application of enzyme cocktail for pulp biobleaching resulted in a 45.64% reduction of kappa number with 55 IU g−1odp of enzyme dose (xylanase:mannanase; 3:1) at pH 8.0 in 1h at 65 °C along with significant increase in brightness (11%) and whiteness (75%). The Same quality of paper as made up from chemical treated pulp can be made from enzyme-treated pulp with 30% less use of chlorine. Structural analysis of enzyme-treated pulp showed dissolution of hemicellulose as indicated by pores, cracks and increased roughness all over the surface. Cocktail of X + M produced economically in a single fermentation having all the requisite characteristics for pulp biobleaching is a highly suitable candidate for application in the pulp and paper industry.

An Outburst by AM CVn Binary SDSS J113732.32+405458.3

Abstract We report the discovery of a one magnitude increase in the optical brightness of the 59.63 minutes orbital period AM CVn binary SDSS J113732.32+405458.3. Public g, r, and i band data from the Zwicky Transient Facility exhibit a subsequent decline over a 300 days period, while a few data points from commissioning show that the peak was likely seen. Such an outburst is likely due to a change in the state of the accretion disk, making this the longest period AM CVn binary to reveal an unstable accretion disk. The object is now back to its previously observed (by SDSS and PS-1) quiescent brightness that is likely set by the accreting white dwarf. Prior observations of this object also imply that the recurrence times for such outbursts are likely more than 12 yr.