STUDY OF METHODS FOR MEASURING THE OPTICAL CHARACTERISTICS OF LOW-PRESSURE MERCURY LAMPS

Obtaining experimental data on the electrical and photometric parameters of low-pressure tubular amalgam lamps with a discharge in a mixture of mercury vapor and inert gases at high current densities of 0.5-1.2 A/cm2 with frequencies of tens of kilohertz is one of the key problems of modern metrology. Since a full-fledged study of the properties of experimental samples of mercury lamps is impossible without a reliable method of photometric measurements, and for ozone lamps such a technique, taking into account the features of the object of study, has not yet been proposed, its development and testing is the main task of this work. Based on the analysis of existing techniques, a technique for measuring the fluxes of the 185 and 254 nm lines of a low-pressure mercury lamp is proposed, taking into account the change in the nature of the spatial distribution of radiation during operation, without directly measuring the RIC. The method proposed by the author for measuring the fluxes of ozonizing and bactericidal radiation can be used as the basis for the development of an automated system for measuring parameters and monitoring the quality of gas-discharge UV radiation sources.

Experimental study on the use of unmanned aerial vehicles for the prediction of oil and gas facilities

The article is devoted to the topical problem of forecasting oil and gas promising objects using the latest remote sensing technologies. The proposed new approach to obtaining field verification data is an essential component of the methodology for solving oil and gas prospecting problems on land (satellite technology).Experimental field studies were carried out using the Ocean Optics STS-VIS Developers kit spectroradiometer installed on a quadcopter. Using the example of the Vostochnorogintsevska area, which is part of the Talalaevska-Rybaltsy oil and gas region of the Dnieper-Donetsk oil and gas region, the main stages of the developed method are demonstrated: a model of the fault-block structure was created, the neotectonic features of this area and its local blocks were estimated, photometric measurements of a multispectral satellite image along the route were carried out, birch leaves were sampled again along the same route for spectrometry using the ASD FieldSpec 3 FR instrument.The main objective of the experiment was to carry out field measurements with the Ocean Optics STS-VIS Developers kit spectroradiometer along a route that repeats the routes of measurements with spectrometers carried out earlier. The results showed that the optical anomaly, which is identified with a hydrocarbon accumulation, along the profile at the Vostochnorogintsevska area corresponds to the segment between points 15-26.The same anomaly has been established with the spectrometry device ASD FieldSpec 3 FR (2009 and 2021), the instrument SF-18 (1999 and 2004). Sufficiently accurately allocated transition from object to background, which corresponds to the boundary of the deposit on the drilling data (point 16 on the profile), i.e. has been confirmed in principle the possibility of allocating a low-intensity optical anomalies over hydrocarbon reservoirs using spectroradiometer STS-VIS Developers kit, mounted on quadrocopter.

Ground Photometric Measurements Inversion Methods for Space Object Characteristics Based on Nonlinear Filtering: A Short Review

: The ground space optical observation system considered as one of the main measurement methods to observe space object in Medium Earth Orbit (MEO), Highly Elliptical Orbit (HEO), and Geostationary Orbit (GEO) experiences difficulties in forming high-solution images for objects located in GEO that only appear as several light spots with limited pixels due to the impacts of observing distance, resolution ratio, and other atmospheric conditions. The light curve is the time duration of an object’s observed brightness. Through light curves, right ascension, and declination of space objects obtained from the ground-based optical observation system, the characteristic of space objects such as position, velocity, size, shape, and material can be inverted. This paper has analyzed the principles, applications, merits, and demerits of several non-linear filtering methods in detail. Besides, the scientific description of inversion for characteristics of a non-resolved space object from ground photometric measurements and the essence of the non-linear filtering inversion method have also been clarified. A selection principle of the non-linear filtering inversion method for different space object characteristics is then proposed, and the developing direction of such inversion methods is also described in the end.

The SAMI Galaxy Survey: stellar population and structural trends across the Fundamental Plane

We study the Fundamental Plane (FP) for a volume- and luminosity-limited sample of 560 early-type galaxies from the SAMI survey. Using r −band sizes and luminosities from new Multi-Gaussian Expansion (MGE) photometric measurements, and treating luminosity as the dependent variable, the FP has coefficients a = 1.294 ± 0.039, b = 0.912 ± 0.025, and zero-point c = 7.067 ± 0.078. We leverage the high signal-to-noise of SAMI integral field spectroscopy, to determine how structural and stellar-population observables affect the scatter about the FP. The FP residuals correlate most strongly (8σ significance) with luminosity-weighted simple-stellar-population (SSP) age. In contrast, the structural observables surface mass density, rotation-to-dispersion ratio, Sérsic index and projected shape all show little or no significant correlation. We connect the FP residuals to the empirical relation between age (or stellar mass-to-light ratio ϒ⋆ ) and surface mass density, the best predictor of SSP age amongst parameters based on FP observables. We show that the FP residuals (anti-)correlate with the residuals of the relation between surface density and ϒ⋆ . This correlation implies that part of the FP scatter is due to the broad age and ϒ⋆ distribution at any given surface mass density. Using virial mass and ϒ⋆ we construct a simulated FP and compare it to the observed FP. We find that, while the empirical relations between observed stellar population relations and FP observables are responsible for most (75 per cent) of the FP scatter, on their own they do not explain the observed tilt of the FP away from the virial plane.

Z-Sequence: photometric redshift predictions for galaxy clusters with sequential random k-nearest neighbours

ABSTRACT We introduce Z-Sequence, a novel empirical model that utilizes photometric measurements of observed galaxies within a specified search radius to estimate the photometric redshift of galaxy clusters. Z-Sequence itself is composed of a machine learning ensemble based on the k-nearest neighbours algorithm. We implement an automated feature selection strategy that iteratively determines appropriate combinations of filters and colours to minimize photometric redshift prediction error. We intend for Z-Sequence to be a standalone technique but it can be combined with cluster finders that do not intrinsically predict redshift, such as our own DEEP-CEE. In this proof-of-concept study, we train, fine-tune, and test Z-Sequence on publicly available cluster catalogues derived from the Sloan Digital Sky Survey. We determine the photometric redshift prediction error of Z-Sequence via the median value of |Δ$z$|/(1 + $z$) (across a photometric redshift range of 0.05 ≤ $z$ ≤ 0.6) to be ∼0.01 when applying a small search radius. The photometric redshift prediction error for test samples increases by 30–50 per cent when the search radius is enlarged, likely due to line-of-sight interloping galaxies. Eventually, we aim to apply Z-Sequence to upcoming imaging surveys such as the Legacy Survey of Space and Time to provide photometric redshift estimates for large samples of as yet undiscovered and distant clusters.

Posture Evaluation and Physical Therapy Intervention Using ISOFREE Medical Equipment, Adapted to Dentists – Case Study

ABSTRACT. Introduction: Dentistry is considered a profession with a high risk of developing musculoskeletal disorders, as a consequence of specific operations involving a high degree of concentration and precision, the whole organism being solicited in a multidirectional manner (Gopinadh et al., 2013). The objectives of the study are to evaluate the dentist’s posture with the help of IsoFree medical equipment and to develop an intervention program specific to postural disorders, most present in dentistry Methods: The research started on the 16th of November 2019 and ended on the 18th of May 2020 and included a case study of one subject. The protocol consisted of ten sessions of evaluation and intervention. The head, cervical and lumbar spine and foot were initially and finally evaluated using photometric measurements and the IsoFree equipment. The physical therapeutic intervention consisted of 19 exercises for each segment evaluated. Results: In the cervical spine, the CVA presents an improvement of 5O and the cranial angle (CA), has undergone an improvement from 26° to 23°, a decrease of 3O. In regard to the real time feedback evaluation with the IsoFree, a 5O improvement from the initial value of 5O was noted after physical therapeutic intervention. In the lumbar spine, the final evaluation on IsoFree reveals a 3O progress of the trunk, the final value being -1O. Using the standardized FPI evaluation, an initial score of +6 has been obtained as well as a final score of +4. In the initial bipodal evaluation with IsoFree, the average CoP X value is 1.88 mm and CoP Y value is 22.47 mm, while in the final evaluation the CoP values on the xOy axis are: 0,53 mm, respectively 13,74 mm. An increase in the values for both parameters of the stabilometry can be observedfrom the initial value of the ellipse surface area of 52.83 mm2 to 123.55 mm2, the final value. The perimeter has changed from 311.34 to 525.93 mm2. Conclusions: The evaluation using the IsoFree technology shows significant benefits while being in accordance with other methods of evaluation. The proposed physical therapeutic intervention has determined positive outcomes on the subject’s posture.

Wide binaries in planetary nebulae with Gaia DR2

Context. The Gaia Data Release 2 (DR2) was used to select a sample of 211 central stars of planetary nebulae (CSPNe) with good-quality astrometric measurements, which we refer to as Golden Astrometry Planetary Nebulae (GAPN). Gaia astrometric and photometric measurements allowed us to derive accurate distances and radii and to calculate luminosities with the addition of self-consistent literature values. Such information was used to plot the position of these stars in a Hertzsprung-Russel diagram and to study their evolutionary status in comparison with the evolutionary tracks of CSPNe. Aims. The extremely precise measurement of parallaxes and proper motions in Gaia DR2 has allowed us to search for wide binary companions in a region close to each of the central stars in the GAPN sample. We are interested in establishing the presence of binary companions at large separations which could allow to contribute additional information on the influence of binarity on the formation and evolution of planetary nebulae. We aim to study the evolutive properties of the binary pairs to check the consistency of spectral types and masses in order to better constrain the ages and evolutionary stage of the CSPNe. Methods. We limited our search to a region around 20 000 AU of each CSPN to minimise accidental detections. We only considered stars with reasonably good parallax and proper motions data, that is, with errors below 30% in DR2. We determined that the hypothetical binary pairs should show a statistically significant agreement for the three astrometric quantities, that is, parallax and both components of the proper motions. Results. We found eight wide binary systems among our GAPN sample, including one in a triple system. We compiled the astrometric and photometric measurements of these binary systems and discussed them in relation to previously published searches for binaries in PNe. By analysing the position in the HR diagram of the companion stars using Gaia photometry, we are able to estimate their temperatures, luminosities, masses and, for one star, the evolutionary age. The derived quantities yield a consistent scenario when compared with the corresponding values as obtained for the central stars using stellar evolutionary models in the postAGB phase.