Incident Rays Research Articles

Array analysis of P-wave polarization data for constraining near-surface shear wave speeds: Aplication to theValley of Mexico seismic network

SUMMARY We present an array method for constraining near-surface shear wave speed values from P-wave polarization data. As the direction of P-wave particle motion is determined both by the incident ray parameter and the local surficial shear wave speed, the latter can be inferred from three-component seismic records if the ray parameter is estimated first. Previous studies have analysed data recorded at a single station from various earthquakes in order to estimate near-surface shear wave speed. In contrast, this paper analyses data recorded at an array of stations. As such, this method can estimate both ray parameter data for the recorded earthquakes and near-surface shear wave speed values at the studied sites. And as an advantage, the method can analyse records of local and regional earthquakes where ray parameter information cannot be reliably estimated using 1D reference velocity models. Additionally, by processing polarization data spanning multiple events and stations, our method provides robust estimates for near-surface shear wave speed values. We apply this array-based method to a seismic array covering the Valley of Mexico. Analysed records correspond to regional earthquakes with epicentral distances of roughly 300 km. The corresponding ray parameter values for all earthquakes were estimated from the delay of the seismic waves arrival throughout the network as all stations have a reliable time reference. Near-surface shear wave speed values estimated from the array-based polarization analysis are correlated with major geological features of the area such as the Trans-Mexican Volcanic Belt and the local basin. We also apply the presented method to a minimal data scenario. The flexibility of this method allows it to employ a single ray parameter value as input, producing robust estimates for near-surface shear wave speed values within our case study. This feature becomes useful in a variety of scenarios, such as utilizing seismic data lacking timing information. The presented method constitutes an accessible and inexpensive alternative to study shallow seismic structure, opening opportunities to expand and complement current tools and techniques to assess seismic hazards.

Highly responsive MoS2/MoO3 heterojunction based broadband photodetector

Broadband photodetection finds indispensable utility across a spectrum of applications, spanning optical communication, spectrum switching, and memory storage. In this work, we demonstrate the fabrication of a heterojunction-based broadband photodetector using visible-infrared activated molybdenum disulfide (MoS2) and ultraviolet-responsive molybdenum trioxide (MoO3). The MoO3-x thin films were grown at room temperature using DC sputtering techniques, and subsequent annealing at varied temperatures mitigated defects, increased crystallinity, and produced stoichiometric MoO3 thin films. Through the sulphurisation of MoO3 via the chemical vapour deposition (CVD) technique, a heterojunction of transition metal oxide/transition metal dichalcogenide between MoO3 and MoS2 is developed. The heterostructure device exhibits broad spectral responsivity, ranging from ultraviolet A to short-wave infrared regions. In particular, ultraviolet ray incidence yields a maximum responsivity of 0.34 A W−1, a minimum noise equivalent power of 1.36 × 10−11 W Hz−1/2, and a maximum quantum efficiency of 119 %. Conversely, under infrared ray illumination, the device achieves a peak responsivity of 13.85 A W−1, a minimum noise equivalent power of 2.89 × 10−13 W Hz−1/2, and the highest quantum efficiency of 1618 %. The ensuing investigations hold promise for advancing heterojunction-based broadband photodetection applications.

Studies on the temperature dependent drift velocity for the HELIX Drift Chamber Tracker

HELIX (High Energy Light Isotope eXperiment) is a ballon experiment designed to measure abundance of cosmic ray isotopes from hydrogen to neon, with a particular interest in abundances of beryllium isotopes. HELIX aim to provide essential data to study the cosmic ray propagation in our galaxy. The Drift Chamber Tracker (DCT) in HELIX is a multi-wire gas drift chamber designed to measure the position of incident cosmic rays. It is located inside a magnet, bending the trajectory of incoming particles through 72-layers of tracking, enabling the measurement of the momentum of incoming particles.Before the data can be used for scientific analysis, the background must be taken out, and the instrument must be well calibrated. In order to exclude electronic noise from the DCT data it was necessary to determine the maximum drift velocity of each wire over a short period of time. To do this I developed an algorithm to be able to identify the maximum drift velocity for each wire over each dataset. This revealed a position dependence of the data within the detector. In order to attempt to characterize this dependence, so it can be accounted for in the calibration stage, I preformed a study on the temperature dependence of the drift velocities analyzing at data from different time periods over the course of the flight. To characterize this dependence I built a predicted heat map of the gas within the detector over the course of the flight. This involved calibrating the thermistors based on data collected when the experiment was on the ground. This helped confirm that the predicted temperature was reasonable and that the variation was temperature dependent. This algorithms and this study can now be applied to the full data set to develop a calibration method.

Zemax Modeling Of A Self-Aligned Focusing Schlieren System With Simulated Compressible Flow

A self-aligned focusing schlieren system is simulated in the ANSYS Zemax OpticStudio software environment. The model uses a custom scatter-defining dynamic link library on the retroreflective background in order to scatter rays in the direction of the incident ray rather than the specular ray. Simulated compressible flow refractive index fields are imported into Zemax by use of the grid gradient object and a workaround to the maximum point limit is introduced. The Ronchi ruling is built as a high resolution bitmap image in MATLAB and set in Zemax as a slide object allowing the bitmap image to either transmit or terminate rays at each line pair. The Zemax simulations are compared to computational numerical schlieren and experimental conventional, path-integrated schlieren results from a hypersonic stagnation point injection flow configuration and an experimental image of a shock wave from a laser-induced breakdown. In the stagnation point injection simulations, the Zemax schlieren images capture complex flow features such as the Mach disk, shear layers, contact surface, and bow shock well, but contains long, curved features (striations) between the model and the bow shock that are not present in the synthetic schlieren image from the CFD or the experimental image. The image from Zemax of the spark-induced shock wave captures the shape and curvature of the shock but appears blurry due to grid discretization in the computational data.

Actinic keratosis and field cancerization: Profile of patients of a dermatology service in the city of Lagarto/SE

Objective: to evaluate the epidemiological profile, pattern of sun exposure, protective measures and lesion characteristics of patients with actinic keratosis and field cancerization in the city of Lagarto/SE. Methodology: this is a descriptive, cross-sectional and quantitative study using questionnaires over a period of 12 months. Results: the sample included 127 participants, the majority was female, with light skin phototype, low education, average age of 60 years and occupations more exposed to the sun. Participants tended to expose themselves to the sun during the period with the highest incidence of ultraviolet rays, the majority used mechanical photoprotection measures, but only about half of them used sunscreen. Of the total, 124 participants reported having skin lesions, most for more than 1 year, with associated symptoms and in areas of the body most exposed to the sun. Conclusion: most participants belong to risk groups for actinic keratosis and/or skin cancer, work in occupations exposed to the sun, in addition to being exposed at the most critical times of the day. The use of mechanical photoprotection barriers was superior to the use of sunscreen. The characteristics of the interviewees' skin lesions may indicate a delay in reaching the specialized service, making it important to adjust the local flow to optimize care for this population and ensure their early referral.

Graphical Interface in MATLAB for design and analysis of reflectors for lighting systems or solar collectors on parabolic surfaces

This project introduces the successful development of a MATLAB graphical interface for the design and analysis of reflectors and solar concentrators on parabolic surfaces. The integration of spline techniques for precise modeling of these surfaces has been implemented, along with the capability to generate STL files for 3D printing. The interface not only enables detailed and adaptable design of reflectors but also includes an advanced simulator for projecting incident rays and analyzing their reflection on the parabolic surface, focusing specifically on the focal point location. This has led to a significant increase in the efficiency of solar concentrators and lighting systems by enabling the precise placement of absorbers to maximize energy transfer. The obtained results confirm the initial hypothesis, demonstrating that the interface enhances the precision and efficiency in the design of these systems, thereby offering a valuable tool in both educational and professional realms in the fields of solar energy and lighting.

Determining the influence of seasonal tilt angle on the efficiency of fixed solar photovoltaic modules

The object of this study is photovoltaic modules with different seasonal tilt angles at different geographical latitudes. The average annual efficiency of photovoltaic modules with different seasonal angles set at different geographical latitudes has been determined as the annual weighted average value of the cosine of the angle of incidence of solar rays on the plane of the photovoltaic module. The influence of seasonal tilt angles of photovoltaic modules at different geographical latitudes on their average annual efficiency was analyzed. Approximate values of the seasonal tilt angles of photovoltaic modules at different geographic latitudes take values that differ from the geographic latitude value by plus 15° for the winter period and minus 15° for the summer period. Modeling the average annual efficiency of photovoltaic modules depending on the seasonal tilt angles at different geographical latitudes made it possible to obtain refined values of the seasonal tilt angles of photovoltaic modules. Thus, at the latitude of 0°, 10°, 20°, 30°, 40°, 50°, and 60°, the tilt angle of photovoltaic modules for the winter period will be 14.8°, 24.6°, 34.5°. 44.4°, 54.1°, 63.6°, and 73°, respectively, and for summer ‒ minus 14.5°, minus 4.6°, 5°, 15.1°, 25.1°, 34.9°, and 44.7°. Dependences were obtained for determining the seasonal tilt angles of photovoltaic modules depending on the value of geographic latitude. The difference in the average annual efficiency of photovoltaic modules, which are installed at seasonal angles, and photovoltaic modules, which track the position of the Sun in the vertical plane, is 0.4 %. The results could be used as a basis for evaluating the efficiency of photovoltaic modules when determining the seasonal tilt angle at different geographic latitudes

Impact of Bi2O3 on the glass system B2O3 -TeO2–MgO–PbO on the purpose of radiation shielding efficacy

In this study, eight glass samples were prepared with the composition of [x Bi2O3-(75-x) B2O3–15TeO2 –5MgO–5PbO; where x = 0, 10, 20, 25, 30, 40, 50, and 60 mol%]. In the composition of those glass samples, various amountsof B2O3 were replaced by Bi2O3 to improve the glass material's radiation shielding capability. The mechanical properties of these glasses have been evaluated using densimeter and microhardness. The Vickers microhardness (Hv) slightly decreases as the amount of Bi2O3 increases due to the formation of Non-Bridging Oxygen (NBO). To evaluate the radiation shielding effectiveness of the prepared glass samples, we performed Monte Carlo simulations of several shielding parameters. The mass attenuation coefficients of the experimentally produced BTMPBi glass series were calculated using NIST and MCNP6, and reasonable agreement was found between the simulation and experimental results. The relative difference between NIST and MCNP6-based results was calculated, and the maximum deviation was 2.21% for the 1173 keV gamma ray incident in the BTMPBi60 glass sample. The value of the mean free path of those prepared glass samples maintained the following trend - BTMPBi0> BTMPBi10> BTMPBi20> BTMPBi25> BTMPBi30> BTMPBi40> BTMPBi50>BTMPBi60. The prepared glass sample BTMPBi0 showed a 2.6 times higher value of the mean free path at energy 1332 KeV compared with the prepared BTMPBi60. Analyzing the composition of the prepared glass samples, it is clear that the greater the amount of Bi2O3 the greater the value of linear attenuation coefficient (LAC) and effective atomic number. Based on the results, it can be concluded that the glass sample containing 60 mol % of Bi2O3 (BTMPBi60) exhibited the highest radiation shielding capability among all of the prepared samples.

Detection of Traveling Ionospheric Disturbances Triggered by 2022 Tonga Volcanic Eruptions Through CubeSats Coherent GNSS‐Reflectometry Measurement

AbstractWe present two case studies of traveling ionospheric disturbances (TIDs) triggered by the 2022 Tonga volcanic eruption observed by low‐cost CubeSat‐based global navigation satellite system reflectometry (GNSS‐R) measurements. The GNSS‐R data used in this work are from Spire Global CubeSats. Our analysis shows that coherent GNSS signals reflected over the ocean can be used to derive precise ionospheric total electron content (TEC) measurements. The first case shows clear TID structures with a TEC disturbance magnitude of ∼1 TEC unit (TECu) and horizontal wavelength of ∼330 km over Northwest Australia on the day of Tonga volcanic eruption. The second case shows the TIDs with ∼0.05 TECu disturbance magnitude and horizontal wavelength of ∼240 km over East Russia the day after the eruption. The second case is likely a TIDs propagated outward from Tonga for the second time after it traversed around the Earth. The GNSS‐R observed TID may be associated with the incident or reflection signal ray path. In this paper, the appropriate ray path was identified using simultaneous observations from ground receiver networks in the areas of both ray paths.

Noise-Generating and Imaging Mechanism Inspired Implicit Regularization Learning Network for Low Dose CT Reconstrution.

Low-dose computed tomography (LDCT) helps to reduce radiation risks in CT scanning while maintaining image quality, which involves a consistent pursuit of lower incident rays and higher reconstruction performance. Although deep learning approaches have achieved encouraging success in LDCT reconstruction, most of them treat the task as a general inverse problem in either the image domain or the dual (sinogram and image) domains. Such frameworks have not considered the original noise generation of the projection data and suffer from limited performance improvement for the LDCT task. In this paper, we propose a novel reconstruction model based on noise-generating and imaging mechanism in full-domain, which fully considers the statistical properties of intrinsic noises in LDCT and prior information in sinogram and image domains. To solve the model, we propose an optimization algorithm based on the proximal gradient technique. Specifically, we derive the approximate solutions of the integer programming problem on the projection data theoretically. Instead of hand-crafting the sinogram and image regularizers, we propose to unroll the optimization algorithm to be a deep network. The network implicitly learns the proximal operators of sinogram and image regularizers with two deep neural networks, providing a more interpretable and effective reconstruction procedure. Numerical results demonstrate our proposed method improvements of > 2.9 dB in peak signal to noise ratio, > 1.4% promotion in structural similarity metric, and > 9 HU decrements in root mean square error over current state-of-the-art LDCT methods.

USING SOLAR ENERGY AS NON-CONVENTIONAL ALTERNATIVE ENERGY IN SMALL AND MEDIUM-SIZED FARMS (Part II)

Considering that every day the sun generates more energy than the planet needs for daily consumption, harnessing solar energy represents one of the future solutions for clean, sustainable energy, obviously with the technological limitations related to the ability to transform this energy into electricity. The paper presents a functional model of equipment that allows the capture of solar energy using special panels, which can rotate both horizontally and vertically according to the sun, so that the incidence of rays with the radiating surface of the panels is maximum and the yields obtained at different angles of inclination in the vertical plane at 60, respectively in the horizontal plane at 0o.

UTILIZAREA ENERGIEI SOLARE CA SURSĂ ALATERNATIVĂ NECONVENŢIONALĂ DE ENERGIE ÎN FERMELE DE DIMENSIUNI MICI ŞI MEDII

Solar energy represents a future solution for clean, sustainable energy, because the sun generates much more energy every day than it is necessary for daily consumption, unlike fossil fuels. The only limitation related to this renewable resource is the ability to transform this energy into electricity. The paper presents a functional model of equipment that allows the capture of solar energy using special panels, which can rotate according to the sun, so that the incidence of rays with the radiating surface of the panels is maximum, and the yields obtained at different angles of inclination (in the vertical plane: 30 and 45, and in the horizontal plane: 0 to be maximum.

ASPECTE PRIVIND UTILIZAREA ENERGIEI SOLARE ÎN FERMELE MICI ŞI MEDII

Considering that every day the sun generates more energy than the planet needs for daily consumption, harnessing solar energy represents one of the future solutions for clean, sustainable energy, obviously with the technological limitations related to the ability to transform this energy into electricity. The paper presents a functional model of equipment that allows the capture of solar energy using special panels, which can rotate both horizontally and vertically according to the sun, so that the incidence of rays with the radiating surface of the panels is maximum and the yields obtained at different angles of inclination in the vertical plane at 60, respectively in the horizontal plane at 0o.

Determining the influence of mounting angle on the average annual efficiency of fixed solar photovoltaic modules

The object of this study is photovoltaic modules with different options for the angle of their installation to the horizon at different geographical latitudes. The scientific problem to solve was determining the dependence of the average annual efficiency of solar photovoltaic modules on the mounting angle of photovoltaic modules and the value of geographical latitude. It has been proven that the efficiency of installation of solar photovoltaic modules can be increased by reducing the angle of their inclination to the horizon depending on the value of the geographical latitude at which they are installed. The average annual efficiency of photovoltaic modules with different mounting angles to the horizon at different geographical latitudes was determined as the annual weighted average value of the cosine of the angle of incidence of solar rays on the plane of the photovoltaic module. The maximum of the average annual efficiency of photovoltaic modules corresponds to a smaller value of the angle of their installation to the horizon than the value of the geographical latitude. So, with a latitude value of 10°, 20°, 30°, 40°, 50°, and 60°, the mounting angle of photovoltaic modules to the horizon will be 9.5°, 18.8°, 28°, 37°, 45.8°, and 54°, respectively. A dependence was derived that allows determining the mounting angle of photovoltaic modules to the horizon dependent on the value of the geographical latitude at which they are installed. A mathematical expression was also constructed that makes it possible to determine the average annual efficiency of photovoltaic modules depending on the angle of their installation to the horizon for different values of geographic latitude. The results could be used in calculating the average annual efficiency of photovoltaic modules based on the adjusted values of the angle of their installation to the horizon at different geographical latitudes

Heat storage and release characteristics of a prototype CaCO3/CaO thermochemical energy storage system based on a novel fluidized bed solar reactor

CaCO3/CaO thermochemical energy storage (TCES) system has a high heat storage density (1780 kJ/kg) along with high heat storage and release temperature (650–850 °C), which can be applied to concentrated solar power (CSP) technology utilizing CO2 Brayton cycles to improve power generation efficiency. There are several problems to be urgently resolved in current CaCO3/CaO solar calciners, such as poor heat and mass transfer and low thermochemical efficiency. This paper proposed a prototype CaCO3/CaO TCES system based on a novel fluidized bed solar reactor, which has a serrated arc surface in alignment with the direction of the incident solar rays to receive concentrated solar energy. The natural limestone particles were used as the reactive particles. The effects of operating modes (intermittent/continuous), initial mass of reactive particles, and initial carbonation temperature Tcar,initial on the heat storage and release characteristics of the TCES system were experimentally explored. During the carbonation reaction stage, the effective carbonation degrees in the continuous mode were generally higher than in the intermittent mode under the experimental conditions and declined at a slower rate. The reactive particles were recovered from the reactor for microstructural characterization after completing the experiments, high-temperature particle agglomeration and pore structure clogging were directly responsible for the decrease of the effective carbonation degree. In the continuous mode, the average thermochemical and total thermal efficiencies of 24.7 % and 53.5 % were obtained in the 1st calcination reaction, respectively, which represents significant advantages over other CaCO3/CaO solar calciners. The novel fluidized bed reactor demonstrated excellent fluidization in the experiments and did not exhibit mechanical deformation after multiple experiments under non-uniform concentrated radiation provided by an 84 kWe high-flux solar simulator. Overall, this paper provides a successful gas-solid reactor design to be coupled with CSP technology.

Transverse electric waves in three-layered waveguide structure with a parabolic spatial profile of the dielectric constant, optical linear and nonlinear layers

A three-layered waveguide structure containing the Kerr nonlinear medium separated by an optical linear interlayer from a parabolic graded-index layer is considered. Exact solutions of the wave equation corresponding to several types of transverse electric waves existing in different ranges of values of the effective refractive index are found. The types of waves differ from each other by the presence or absence of oscillations in the interlayer and in the graded-index layer, as well as the form of attenuation in a nonlinear medium. The wave types obtained can be divided into two main groups. The first group includes such waves that can propagate with an arbitrarily varying effective refractive index in the allowable range of values. The second one includes such waves that can propagate at certain discrete values of the effective refractive index. Such values of the effective refractive index of waveguide modes are determined by the wavelength of the incident ray, difference between the dielectric constants of a parabolic graded-index layer, and its width. Even and odd waveguide modes are described separately. Field oscillations can be observed only in the interlayer for waves of the first group. Field oscillations can also be observed in the graded-index layer for waves of the second group. The field profile is a self-focusing nonlinear medium flatter than in a defocusing one for all types of waves. An increase in the same parameters has a different effect on the profiles of the different types of waves. The possibility of controlling the distribution of the wave energy between the layers of the waveguide structure by changing the angle of incidence is shown.

ENHANCING TERRESTRIAL POINT CLOUDS USING UPSAMPLING STRATEGY: FIRST OBSERVATION AND TEST ON FARO FLASH TECHNOLOGY

Abstract. Nowadays 3D digitization through the combination or hybridization of different sensors, with the final aim of accelerating the phases of data acquisition and storage, develops user friendly and robotics systems, making efficient the operator role. New technologies as Hybrid Reality Capture™ (HRC), with Flash Technology (FARO Tech.) certainly fits into this market trend, and it is characterized by rapid acquisition, involving 3D scanning data with panoramic images contribution. The system is still under patent, and nothing is yet released on the technology. This research presents the analysis and discussion of results based on the raw and processed data related to the new FARO system. The assumption – based on the information declared by the manufacturer (FARO, 2023) – is that the new colored Flash scans are faster and denser than scans of the same resolution obtained using traditional static scanning method, due to the crucial contribution of the PanoCam data and resolution on which the upsampling strategy is based. An evaluation based on detailed analysis of the upsampling results is reported, delivering that the surface point density exponentially decreases with the distance and with the ray incidence inclination. A comparison with a mobile mapping technology is finally presented and discussed.

Novel composite based on silicone rubber and a nano mixture of SnO2, Bi2O3, and CdO for gamma radiation protection

Recently, there has been a surge of interest in the application of radiation-shielding materials. One promising research avenue involves using free-lead metal oxides/polymer composites, which have been studied for their radiation shielding and characterization properties. This study reinforced the dimethylpolysiloxane (silicone rubber) composites with micro- and nano-sized particles of tin oxide, cadmium oxide, and bismuth oxide as additive materials. The composites were tested with 20 and 50 weight fractions, and their attenuation coefficients were measured using a NaI(TI) detector at gamma-ray energies ranging from 59.54 to 1408.01 keV. Also, the thermal and mechanical properties of the composites were observed and compared with those of free silicone rubber. The results showed that the 50% nano metal oxide/SR composites exhibited better thermal stability and attenuation properties than the other composites, also possessing unique attributes such as lightweight composition and exceptional flexibility. Consequently, this composite material holds immense potential for safeguarding vital organs, including the eyes and gonads, during radiological diagnosis or treatment procedures. Its exceptional ability to absorb a significant portion of incident rays makes it an invaluable asset in the field of radiation protection.

Ray Tracing and Simulation of Parabolic Dish Collectorusing Soltrace for Vehicle Applications

Concentrated solar power has the potential to produce large-scale renewable energy sources. Concentrated solar energy is produced using mirrors, reflective materials, or lenses on conical surfaces such as a parabolic dishes, parabolic troughs, towers, Fresnel reflector systems, and dish sterling collectors. The concentrated light source was converted into heat energy, which drove the heat engine into an electrical power generator. To gain more heat energy, the solar rays must be trapped and concentrated on their conical focus points. To increase the net overall efficiency of the system, it is vital to know the optical performances of the subsystem formed by the solar receiver and the parabolic concentrator. In this study, a beam of incident solar rays was traced on a parabolic dish collector, and a simulation is performed for concentrator behaviour using the ray-tracing code SolTrace developed by the NREL laboratory. For an incident radiation of 1000 W/m2 (considering 10000 photon rays), their optical performance and solar heat flux were simulated. The results show that the number of elements in SolTrace varies depending on the CFD mesh density, the number of rays utilised in the Monte Carlo technique and their impact on generating a resolution-independent solution. Investigating the ray tracing of the disc concentrator, the propulsive energy for viable applications can be analysed.

Remote Determination of Wool Color

Analysis of the financial condition of the sheep industry is partly due to the low color purity of sheared wool, in the absence of animal selection to form sheep flocks with the same stripe color and the creation of conditions that would make it impossible to mix animals in flocks with different colors. To enable the above objectives to be achieved, theoretical studies of the conditions of reflection and absorption of optical radiation by the wool coat of animals were carried out, for which purpose the model of the incident ray interacting with the surface of sheep wool was improved and studied. The role of the reflected flux in diffuse scattering on individual wool layers is determined and a model of the reflected flux in the presence of local internal inhomogeneities is developed. The obtained functional dependences characterizing both the reflected and scattered light made it possible to formulate the requirements regarding technical implementation of the proposed method of flock formation by wool color.