Incident Rays Research Articles

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.

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.

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.

Development and Baseline Comparison of a New Pulsed-Neutron Spectroscopy Tool for Carbon- Oxygen Analysis and Three-Phase Saturation Monitoring

A new slim multidetector pulsed-neutron wireline-logging tool has been developed for openhole or casedhole formation evaluation saturation analysis and time-lapse monitoring. With a greater neutron source output and high-spectral resolution gamma ray detectors, the tool can be operated with reduced uncertainty or faster logging speeds. New, fully programable digital electronics provide a range of acquisition modes optimized for specific formation evaluation objectives. Neutrons are generated from a high-output pulsed-neutron generator, which propagates radially outward, passing through the borehole, completion material, and into the formation. Energy is lost through scattering, and neutrons are absorbed by the surrounding material. Gamma rays are emitted from scattering and absorption interactions at discrete energies, which can be measured by one of three spectral gamma scintillation detectors. The energy distribution of these incident gamma rays by inelastic and capture interactions is affected by the elemental composition of the material. A salinity-independent oil-water saturation assessment begins with the deconvolution of neutron-induced gamma ray inelastic spectra into constituent elemental components. Carbon-oxygen ratios (C/O) of elemental yields are then compared to a reference model to determine the relative saturation and porosity-filled volume of oil and water. In PNC (pulsed-neutron capture) acquisition mode, a salinity-dependent oil-water saturation assessment is determined from neutron capture cross section (sigma) measurements, which are compared to formation and porosity fluids using a mass balance approach. Gas saturation assessment is determined from gas-sensitive inelastic (RIN13) and capture (RATO13) ratios. Gas ratios are compared to a reference model to assess the relative saturation of fluids, typically distinguishing gas from water or gas from oil. Gas saturation is not limited to hydrocarbon components and can also be used for saturation analysis of H2, He, CO2, N2, and other non-hydrocarbon-bearing components. A new Omni-mode acquisition combining simultaneous PNC and C/O measurements was also developed. This acquisition mode provides advantages in reducing multipass logging typically required from separate PNC and C/O acquisitions. By including PNC neutron capture sigma, gas-sensitive neutron capture and inelastic measurements, and C/O inelastic measurements, the simultaneous Omni-mode (PNC+C/O) acquisition is specifically optimized for three-phase saturation analysis applications, including baseline CO2 sequestration evaluation for carbon capture, utilization, and storage (CCUS) CO2 and steamflood time-lapse monitoring. Results from a field example are presented to demonstrate the new technology with spectral C/O saturation analysis compared to traditional windows C/O analysis and to compare the performance of the next-generation tool to the legacy tool. Multiphase saturations from C/O and RIN13 measurements and compatibility with legacy interpretations for time-lapse saturation monitoring are also presented.

SunSync Innovation: Empowering Traditional Solar Flat Plate Collectors with Autonomous Sun-Tracking for Tea Leaf Drying

Aim: This research focused on post-harvest technology for preserving tea leaves. The research introduces an innovative approach by incorporating an autonomous solar tracker into a flat plate solar collector, strategically optimizing its orientation towards the sun. The solar tracker, a low-cost and fully automatic prototype, plays a pivotal role in maximizing incident solar rays, thereby enhancing the overall energy absorption efficiency of the system at the same time increasing the quality of dried tea leaves.
 Methodology: The investigation delves into the realm of indirect solar drying methodologies, with a specific focus on the Sun-Tracking Solar Dryer (STSD). This sophisticated apparatus, engineered through the integration of light-dependent resistors, a wiper DC motor with gearbox, and a microcontroller, was developed within the confines of the Agricultural and Food Engineering department at IIT Kharagpur. Subsequent to its development, the study entails a comparative analysis wherein the position of the absorber in the dryer, as ascertained by the developed prototype, is juxtaposed with the ideal position requisite for optimal solar light incidence. Moreover, an examination of the dried tea leaves produced by the prototype is conducted, involving a comprehensive comparison with those dried using the conventional open sun drying method.
 Results: The instantiated prototype demonstrated commendable efficacy in aligning with the ideal position, exhibiting an average deviation of 3.25 degrees. Facilitated by this prototype, the attainment of the targeted moisture content in tea leaves was expedited, culminating 2 hours earlier than the conventional open sun drying method. The resultant dried product manifested a water activity of 0.531 and a DPPH radical scavenging activity of 73.53%, both registering a reduction in comparison to the open sun drying counterpart. Concurrently, the total phenolic content exhibited an increment of 11.48% when contrasted with the open sun drying process.
 Conclusion: The affordably developed prototype demonstrated exceptional capabilities in sun tracking, showcasing the promising potential for augmenting the efficiency of conventional flat plate solar collectors. Additionally, its performance in preserving the quality attributes of dried tea leaves was commendable.

Localising and identifying radionuclides via energy-resolved angular photon responses

A technique for the in-situ localisation of radioactivity is described whereby the energy-resolved angular photon response of a collimated inorganic scintillation detector is used to derive the spatial arrangement of a variety of radioactive source configurations. The influence of photon radiation (X- and γ ray) incident on the collimated detector is expressed mathematically, by way of a sinc transform embedded to a dynamic linear regression model, to increase the spatial accuracy of the localisation. This approach is tested experimentally with two pairs of like radionuclides, two pairs of different combinations of radionuclides and three different radionuclides to demonstrate its combined isotopic discrimination and spatial localisation capabilities. A fit based on the model referred to above is observed to reproduce the data for the combined X- and γ-ray regions of interest effectively. This allows for increased resolution via interpolation between the data which is observed to improve location accuracy significantly. This research is relevant to applications in autonomous robotic exploration tasks and for the characterisation of contaminated environments associated with nuclear legacies and radiological emergencies.

Underwater acoustic self-focusing and bending in conformal Mikaelian lens by pentamode metafluid

In this paper, we present the design of an arc-shaped Mikaelian lens using conformal transformation acoustics. We have derived the propagation trajectory equation for vertically incident rays within the lens. The ray trajectories inside the designed lens exhibit the feature of self-focusing as well as of deflection of the propagation direction. The microstructure design of the lens is realized using pentamode material unit cells, which provide the necessary property for underwater acoustic wave manipulation. The simulation results demonstrate that the designed lens has a good self- focusing effect and can deflect the propagation direction of incident waves at the same time. The pentamode conformal Mikaelian lens shows potential applications in underwater imaging, detection and communication.

The path of a light ray in a semicircular cavity

It is well known that the path of a light ray incident on the inner reflecting wall of a circular cavity can be constructed by geometric means. Analogous to what is done in this more common geometric configuration, trajectories of light rays in a semicircular closed region with perfectly reflecting inner walls are found. A ruler-and-compass method for obtaining these trajectories is illustrated.

Geometric characteristics and design optimization of parabolic trough concentrators with a flat mirror as the secondary reflector designed based on two components of a solar source

Parabolic trough concentrators with a tubular receiver (PTCs) are widely used for the production of solar thermal power. However, the geometric concentration ratio (CR) of PTCs falls short of thermodynamic concentration limit (C0) by a factor larger than π, and restricted by the angle subtended by solar sources (Δs = 2θa). To increase CR, a novel idea by dividing a solar source into two components in the open angle is proposed for the design of PTC equipped with a secondary reflector (SR), and PTC with a flat mirror (FM) is designed as a trial of the idea. For such design idea, rays incident at rims of primary parabolic reflector (PR) from one component (S1) are required to directly redirect onto on the absorber tube (AT) and those from another component (S2) are required to arrive on the AT after reflections from PR first then from FM. To investigate effects of the angular division factor (k) of solar sources (Δs2 = kΔs) and rim angle (ϕe) of PR on the effective CR (Cg), a mathematical procedure to characterize the geometry is suggested and examined by ray-tracing technique. The analysis shows that the geometry of PTC-FM is dependent on k, ϕe and θa, and a set of optimal k and ϕe for maximizing Cg can be obtained when θa is given. Calculation results show that the optimal k for maximizing Cg is 0.5 regardless of θa, but the optimal ϕe of PTC-FM for maximizing Cg, is sensitive to θa. As compared to conventional PTCs, the Cg of optimized PTC-FM is increased more than 80%, larger than 56.5% of C0, for k = 0.5 and θa < 1.0°. Empirical expressions for a quick estimation of optimal ϕe are also proposed based on numerical calculations. Results by ray-tracing analysis indicate that the optimal ϕe for maximizing CR and average solar concentration ratio are almost identical when the reflectivity of PR and FM is higher than 0.8. In principle, the novel idea is applicable for the design of other solar concentrators, therefore a further increase of Cg of PTCs is possible by using other imaging and non-imaging optics as the SR.

Determining the efficiency of installing fixed solar photovoltaic modules and modules with different tracking options

The object of this study is photovoltaic modules in various installation options. The physical model of the Earth's illumination by a parallel flow of solar rays has been refined. The dependence of the cosine of the angle of incidence of the Sun's rays on the angular length of the day, as well as the average annual efficiency of the installation of photovoltaic modules, both fixed and with various tracking options, was determined. Refinement of the physical model implies determining the angle of inclination as the angle between the inclined axis of the Earth and its projection on a vertical plane, perpendicular to the line connecting the centers of the Earth and the Sun. This line passes through the center of the Earth. The concept of the average annual efficiency of the installation of photovoltaic modules is introduced as the annual weighted average value of the cosine of the angle of incidence of solar rays on the plane of the photovoltaic module. Various options for installing photovoltaic modules were analyzed: fixed horizontal on the equator; stationary, installed at an angle to the horizon; one that performs tracking in horizontal (vertical) planes; with full tracking. The efficiency of installing a photovoltaic module at each latitude can be equal to the efficiency of installing this module at the equator, that is, 47.93 % when installing the module at an angle of inclination to the horizon equal to the latitude. Tracking in the vertical plane makes it possible to increase the efficiency of the photovoltaic module installation by up to 50 %. Compared to full tracking, tracking in the horizontal plane at an angle of latitude makes it possible to obtain the efficiency of the installation of the photovoltaic module at the level of 97.93 %. The results could be used as a basis for evaluating the efficiency of the installation of photovoltaic modules at different latitudes with different techniques of their installation, as well as for the subsequent generation of electricity