Incident Rays Research Articles

RANCANGAN PERCOBAAN INFRARED THERMOMETER: KALIBRASI DAN KEUNGGULAN PEMANFAATANNYA

His experiment aims to determine whether the reading of the infrared thermometer depends on the distance or angle of the incident ray, know the calibration and validation of the infrared thermometer and determine the temperature as a function of position and time for 1-D and 2-D objects and analyze the measurement results. The first experiment was carried out on objects with different areas, namely walls and small aluminum slabs with a size of 3.8cm x 3.8cm. The second experiment was also conducted on different objects, namely water with a temperature of 30oC and 60oC, which was measured at the same temperature using an infrared thermometer and an alcohol thermometer. The third experiment was carried out on 1D objects with 2 different types of materials and one type of 2D material. From the results of the experiment it can be concluded several things, for experiment one obtained differences in the reading of the thermometer at various angles and distances for object 2 (small plates), while for objects with large areas such as thermometer reading walls remain the same for different distances and angles. The thermal conductivity coefficient of aluminum is greater than iron.

Low Cost High-Accuracy Compound Parabolic Concentrator System—A Manufacturing Methodology

Abstract One of the problems of designing a solar compound parabolic concentrator (CPC) is related to its manufacturing shape accuracy. The complexity of curving and holding the CPC profile in place is indeed a challenging issue, especially because there are no standardized molds and the process is typically handmade. It is very easy to provoke misalignment on the CPC surface and in consequence, divert the solar incident rays, affecting significantly the optical efficiency of the system. This work presents a novel, inexpensive methodology to manufacture a CPC with accuracy by using basic tools. The design starts with the acquisition of a pair of medium-density fiberboard wooden templates of the CPC profile that are used later to make a Styrofoam CPC mold and then cut with a hot-wire technique. A high-reflectance anodized aluminum sheet is curved to approximate the CPC shape and is then coupled with the temporary Styrofoam mold. The last part consists of the elaboration of a housing system to contain the parts. This is consolidated by a polyurethane resin that expands and fills all enclosure cavities, offering stiffness and stability. A photogrammetry analysis was implemented for the validation of the surface shape accuracy. The results from the optical analysis show that this technique achieved a high degree of accuracy and homogeneity on the CPC surface shape.

A subspace-based code tracking loop design for GPS multi-antenna receiver in multipath environment

Global Navigation Satellites Systems have been greatly developed in recent years, but receivers usually suffer the undesired measurement bias errors caused by multipath incidence in an urban area. We propose an effective subspace-based estimator cooperating with the conventional delay-locked loop (DLL) for Global Positioning System L1 C/A Signal. With the help of the multi-antenna, the incident rays could be distinguished in space. A forward and backward space spatial smooth technique is then taken to solve the coherent problem in signal subspace estimation. By using the structure of the receiving array, a subspace rotation invariance can be built, and the angles of arrival and relative delays of incident rays could be estimated jointly. After combining the estimates from DLL and subspace-based estimators, we can enhance the strength of the line-of-sight ray and achieve a modified delay tracking output without multipath bias effectively. Simulation results prove that compared with the existing methods, such as the narrow early-minus-late and the multipath estimating delay lock loop, the proposed method has the best multipath mitigation in the delay estimation.

Lensless light-field imaging through diffuser encoding

Microlens array-based light-field imaging has been one of the most commonly used and effective technologies to record high-dimensional optical signals for developing various potential high-performance applications in many fields. However, the use of a microlens array generally suffers from an intrinsic trade-off between the spatial and angular resolutions. In this paper, we concentrate on exploiting a diffuser to explore a novel modality for light-field imaging. We demonstrate that the diffuser can efficiently angularly couple incident light rays into a detected image without needing any lens. To characterize and analyse this phenomenon, we establish a diffuser-encoding light-field transmission model, in which four-dimensional light fields are mapped into two-dimensional images via a transmission matrix describing the light propagation through the diffuser. Correspondingly, a calibration strategy is designed to flexibly determine the transmission matrix, so that light rays can be computationally decoupled from a detected image with adjustable spatio-angular resolutions, which are unshackled from the resolution limitation of the sensor. The proof-of-concept approach indicates the possibility of using scattering media for lensless four-dimensional light-field recording and processing, not just for two- or three-dimensional imaging.

Pseudophakic Dysphotopsia: Review of Incidence, Cause, and Treatment of Positive and Negative Dysphotopsia

We reviewed the literature concerning positive dysphotopsia (PD) and negative dysphotopsia (ND) regarding cause, incidence, and clinical and surgical management. In addition, we summarized our surgical experience in managing dysphotopsia. A PubMed review, limited to English language articles, yielded 149 citations; multifocal (diffractive optic) and phakic intraocular lens (IOL) dysphotopsia were excluded. Overall, 39 articles were determined to be relevant for the objectives of this investigation. Regarding PD, 7 articles corroborated that the cause of PD is related primarily to internal reflection of oblique light rays that strike the square (truncated) edge of the IOL and are reflected onto the retinal surface. No round-edged foldable IOLs are available in the United States at this time, although IOLs modified with a round anterior edge and square posterior edge show a trend toward decreased incidence of PD. High index of refraction (I/R), surface reflectivity, and IOL optic design are additional causative factors for PD. Regarding the authors' surgical experience, changing the optic material to have a lower I/R improved PD symptoms in the large majority of patients. The cause of ND seems to be multifactorial and less well understood, with some disparity between clinical and laboratory findings. Four articles that explore using ray-tracing optical modeling suggest an "illumination gap," in which some temporally incident light rays to the nasal retina pass anterior to the IOL and some are refracted posteriorly by the IOL, resulting in a gap and resultant temporal shadow. However clinically, ND is associated invariably with well-centered in-the-bag IOLs. Other implicating factors include nasal anterior capsule override, haptic orientation, large-angle κ value, and high hyperopia. Persistent ND has been treated successfully or reduced with reverse (anterior) optic capture, sulcus IOL placement, piggyback IOLs, and neodymium:yttrium-aluminum-garnet nasal capsulectomy. Two articles reference a new optic edge designed to capture the anterior capsulotomy, mimicking reverse optic capture. Persistent dysphotopsia after cataract surgery is a significant cause for patient dissatisfaction. The cause and management of both ND and PD are of significance, and new IOL designs and alternative surgical strategies may help to mitigate these unintended side effects of IOL implantation.

A comprehensive mathematical approach and optimization principle for solar flux distribution and optical efficiency in a solar tower

While designing and optimizing a concentrating solar central tower, it is crucial to obtain the accurate solar flux distribution and optical efficiency for a given heliostat field. Here we present a new model describing solar flux distribution on the surface of an external receiver, based on ray-tracing and a convolution algorithm. The receiver is located at the top of a center tower surrounded by abundant heliostats. The Ray-tracing algorithm allows to predict whether the incident ray is obstructed by adjacent mirrors or not, and the convolution algorithm yields the solar flux distribution on the reflected beams. The performance of single and multi-mirrors are compared with experimental data. Results show that the optical efficiency and solar flux distribution are mainly controlled by the interception factor, and shading and blocking factor. A comprehensive optimization principle is proposed to optimize the optical efficiency of heliostats field. Accordingly, application of this principle increases the average optical efficiency by+2% during daytime, while decreases the ratio of maximum solar flux to the minimum one from 8.6 to 7.8.

Dielectric metalenses at long-wave infrared wavelengths: Multiplexing and spectroscope

Metalenses, being composed of subwavelength phase-control nanostructures, can achieve peculiar manipulations of incident rays. Dispersion is one of the key optical characteristics to be eliminated or exploited in designing broadband optical systems. In the study, the silicon metalenses made of nanobricks are investigated to achieve multiwavelength multiplexing or spectroscope in the long-wave infrared regime. Firstly, the geometrical dependencies of silicon nanobricks’ transmittance, phase difference, and structural dispersion are investigated to obtain the fundament of constructing the metalenses. Then, the metalenses are constructed, of which the chromatic aberration is analyzed. Via spatial multiplexing, two multiwavelength-metalens configurations are proposed to realize achromatism and multifocal features respectively. Furthermore, via exploiting the nanobricks’ structural dispersion, a compact spectrometer based on an off-axis metalens is demonstrated. This study gives out an insight into exploiting the structural dispersion of silicon nanobricks in constructing metalenses, which paves an efficient way for the development of integrated imaging and spectroscopy systems in the long-wave infrared range.

The generalized vectorial laws of reflection and refraction leading to the development of novel equations involving the coordinates of the source point, point of observation, and the point of incidence

This paper considers the derivation of novel equations involving the coordinates of a pair of points lying respectively on the incident ray and the reflected (refracted) ray as well as those of the point of incidence by making use of the generalized vectorial laws of reflection and refraction developed by the author in 2005. The novel equations developed will be applicable irrespective of the positions of the pair of points lying on the incident ray and the reflected (refracted) ray respectively. If, however, one of the pair of points considered is supposed to be the source point and the other one is considered as the point of observation, then such novel equations will effectively represent the relation(s) between the coordinates of the source point, point of observation and the point of incidence. The problem addressed is novel and interesting and the development of such novel equations increases the range of applicability of the generalized vectorial laws of reflection and refraction, there by enhancing the traditional optical physics literature as well.

Интерферометр для контроля углов клиньев

The paper considers an optoelectronic laser interferometer system to control wedge angles. This system records an interference pattern on an image sensor. The interferometer makes it possible to estimate the small angle of the wedge under investigation by the variation it introduces into the shape of the optical radiation wavefront, which the interferometer then converts into changing the size of the interference pattern. In the interferometer considered, the wedge under investigation refracts the incident ray cone. The error inherent in surface finishing causes the deformation of the working wavefront to be 2 to 4 times smaller as compared to the deformation in previously known control setups involving reflection from the wedge surfaces. The interferometer developed ensures highly accurate control of wedge angles at the surface polishing stage, including potential detection of wedge direction. If required, the interferometer may be used for comprehensive quality control of wedge manufacturing, assessing not only the surface nonplanarity, but also glass inhomogeneity; it may also be used to control prism angles

Multi-element lenslet array for efficient solar collection at extreme angles of incidence

Photovoltaics (PV) are a versatile and compact route to harness solar power. One critical challenge with current PV is preserving the optimal panel orientation angle with respect to the sun for efficient energy conversion. We experimentally demonstrate a bespoke multi-element lenslet array that allows for an increased power collection over a wide field of view by increasing the effective optical interaction length by up to 13 times specifically at large angles of incidence. This design can potentially be retrofitted onto already deployed amorphous silicon solar panels to yield an increased daily power generation by a factor of 1.36 for solar equivalent illumination. We 3D printed an optical proof of concept multi-element lenslet array to confirm an increase in power density for optical rays incident between 40 and 80 degrees. Our design indicates a novel optical approach that could potentially enable increased efficient solar collection in extreme operating conditions such as on the body of planes or the side of buildings.

Simulation of anti-reflecting dielectric films by the interference matrix method

In this work, the reflection coefficients of multilayer and gradient dielectric films are simulated. The basis of the conducted researches is the theoretical analysis of reflection coefficients for single and double layer films, which use the criterion of zero reflection coefficients for electromagnetic wave with a given wavelength. The specified length is selected based on the maximum spectral density data of the solar radiation. Numerical calculations were performed on the basis of the interference matrix method. Using this method, the reflection coefficients were calculated for the spectral range of electromagnetic radiation, in which photoelectric conversion of solar cells made of silicon occurs. The dependences of the reflection coefficients on the angle of incidence of the sun's rays are also calculated. Numerical methods were used to determine the average values of the reflection coefficients, taking into account the spectral density of solar radiation. Optimal values of the thicknesses of single and double layer films were found as well as gradient films with the linear law of change of the refractive index of the film material. The optimum values found were compared with the characteristics of the dielectric coatings used in solar power. Both traditional technologies based on CdTe and Cu(In,Ga)Se2 crystals and relatively new technologies based on the use of nanostructured films and porous silicon films have been considered. For these materials, the characteristics of the films are calculated, which provide values of reflection coefficients that are close to optimal values.

Optical Analysis and Reappraisal of the Peripheral Light Focusing Theory of Nasal Pterygia Formation.

PurposePterygia are much more common nasally than temporally. Ultraviolet (UV) radiation is a major risk factor. Coroneo proposed that the nasal preference is caused by the “peripheral light focusing effect,” (PLF), in which UV at an oblique angle passes through temporal cornea and is concentrated on and damages nasal limbal stem cells. This study evaluates whether the PLF is sufficient to explain the nasal preference.MethodsWhereas Coroneo and colleagues derived the maximum PLF intensity gain (UV concentration factor) as a function of incident angle (i.e., different nasal limbal positions were used for different incident angles) the current analysis derived intensity gain at a fixed position such at the nasal corneo-limbal junction (CLJ). This provided a measure of the total PLF irradiation at this position, which was compared to total direct irradiation of nasal and temporal limbus at the corresponding positions (e.g., CLJs). In Part 1, analysis was performed like that of Coroneo, using horizontally incident UV; in Part 2, the analysis was extended to include incident rays above and below the horizontal.ResultsIn both part 1 and part 2 of the study, the limbal UV irradiation of the nasal limbus from the PLF was not sufficient to explain the strong nasal location preference of pterygia.ConclusionsThe analysis calls into question the PLF explanation of nasal location preference. Other explanations of the nasal preference, and of pterygium pathogenesis, should be considered, such as temporal to nasal tear flow carrying substances such as cytokines to the nasal limbus.

Method of O.Podgorny determination of the phase reflected wave corresponding wave phase from a point source

A method for constructing, using a computer, the envelope of a family of circles of variable radius, the centers of which are located on a given curve G and touch the circle C with the center at the origin, is given. In this case, the limits of the parameter t Î [a, b], which determines the position of the center of each family circle on the curve G., are taken into account. In solving this problem, in the general case, the question arises of ordering the set of calculated coordinates of points on the corresponding branches of the envelope, which is difficult to formalize. In this paper, it is proposed to simplify the process of approximate finding of points on the envelope by calculating the coordinates of the points of intersection of "neighboring" pairs of circles. Namely, from N circles of the family SN, their pairs SK and SK+1 (K = 1..N-1) are sequentially selected, and common points are calculated for them. Then it can be argued that the set of found intersection points of all circles will be located on the branches of the desired envelope. О. Podgorny suggested using the above geometric model for interpretation at the graphic level of the relationship between the phases of the incident wave on the curve Г and the reflected wave from the curve G. Let the origin point be the source of the incident wave. Then the phase of the reflected wave from curve G can be considered orthotomics. The possibility of using orthotomics as lines for which the reflected rays constitute, respectively, a bundle or congruence of normals, О. Podgorny also demonstrated for the case of parallel incident rays. Here, as a basis for constructive constructions, mappings from a line in a plane were considered. The direct and orthotomics in the plane are the fronts of the incident and reflected waves, respectively, since the incident and reflected rays are their normals. The paper presents a computer implementation of the graphical method for determining the individual phases of the reflected waves, which correspond to the phases of the wave with a point source. These studies are important in solving problems in the field of architectural and construction physics and solar technology, which require the further development of constructive methods for modeling the reflected streams of sound or light.

Vegetables cultivation under protected conditions

In addition, the biotic stresses also do not allow successful production of vegetables like capsicum, cucumber, tomato, chilli, okra/bhindi, cauliflower, cabbage, leafy vegetables etc. in the fields mainly during rainy and winter season. In spite of the great importance of vegetable crops, it faces a lot of restraints like temperature stress, photostress, moisture stress and weeds growth, nutrients deficiency in the soil, excessive wind velocity and atmospheric CO2. Some possible ways to reduce green house gas emissions are suggested and some sustainable adaptation strategies are indicated. We expand our survey of the existing research to the entire production system, including greenhouse structure, energy, electricity, growing media, and fertilizers. Different protected cultivation structures having different temperature, humidity, UV radiation ranges and also having different cost involvement in construction of structure which may results the production of vegetables with distinct advantage of good quality fruits, productivity and favorable market price to the growers/farmers. These limitations can be alleviated by adopting a unique, specialized hi-technology is called as protected cultivation. Intense heat and high incidence of UV rays in dry months reduce the quality of leafy vegetables in open which otherwise very good in protected structures. Protected cultivation has great scope to achieve self-sufficiency in vegetable sector even with less area. The shade net house is ideal for cultivation of vegetable during dry period in the tropical islands when extreme sunshine and heat are limiting factor to vegetable production. These structures are constructed using a UV stabilized agro-shade net (35%-70% shade) materials for creating partial shade condition inside the structure to favour the growth and development of partial shade requiring crops or to protect crop from scorching heat during hot/summer months. The partial shade effect helps in fast and better growth of leafy vegetables besides reducing the evapo-transpiration loss of water. Low cost shade net for high value leafy vegetables like coriander, palak, fenugreek and insect free brinjal crop. Consequently more pesticides are being used for protecting the crops which deteriorate the vegetable quality by the presence of residues. This also creates environmental concern as the limited soil and fresh water bodies are get contaminated. The net house can be used for year round cultivation of crops such as Capsicum, tomato, okra, cauliflower, cabbage, brinjal, beans, parthenocarpic cucumber and other cucurbits with reduced incidence of insect-pest and diseases and consequent low chemical residues on the produces. The cost can be reduced drastically by the use of local wood materials like bamboo/wooden poles. Vegetable growers can substantially increase their income by protected cultivation of vegetables in off-season as the vegetables produced during their normal season generally do not fetch good returns due to large availability of these vegetable in the markets. Off-season cultivation of cucurbits under low plastic tunnels is one of the most profitable technologies under northern plains of India. Protected cultivation enables us to grow vegetables in the off-season and also to extend the vegetable growing seasons for a much longer period than is possible under open field conditions. Though certain breakthroughs in vegetable cultivation in adverse climates using protected devices have been registered, more extensive research and generation of awareness are required to tap potential of protected cultivation of vegetable crops and also increase the area under protected devices.

Câncer de pele na região Norte do Brasil: levantamentos das notificações de 2014-2019

Introduction: Skin cancer is the most common neoplasm malignancy worldwide and is subdivided into melanoma and not melanoma. Brazil, being a tropical country and with a high incidence of UV rays, is one of the countries in the world most affected by this type of neoplasia. Objective: To describe the profile of patients with skin cancer in the northern region of Brazil, in the period from 2014 to 2019, using the data reported and present in DATASUS. Method: Historical series of skin cancer cases reported in the North of Brazil, between the years 2014 and 2019, accounted for through the DATASUS platform. Results: In the last 5 years, 2,610 cases of skin cancer were reported in the North, with Rondônia, Pará and Amazonas being the most affected states (for every 100 thousand inhabitants). Non-melanoma skin cancer is the most common, affecting mainly men over 40 years of age. The death rate is the lowest compared to all regions of the country and the world rate. Conclusion: Due to the deficit in medical care in the North, it is partly explained by the low number of skin cancer diagnoses and the lack of data on the platform.

Hydrostatic Fiber Optic Liquid Level Sensor with position sensitive detector

This article presents the rationale and methodology for developing an intrinsically safe device, namely, a hydrostatic fiber optic sensor with a position-sensitive detector for monitoring the level of oil products in large-capacity tanks at oil depots and during pumping in a raw material warehouses. This device suitable for continuous monitoring of the liquid level, based on the measurement of a hydrostatic column of liquid with automatic offset of changes in the density of the liquid. Offset is carried out by means of a displacer (a fully submerged float), inside which a housing with a position-sensitive detector (PSD) is integrated. Theoretical validation of the bellows suspension usage for a displacer is given. During filling a container with a liquid whose level is measured, liquid bellows, the movement of which is recorded by an optical triangulation sensor using the reflected infrared ray incident on the bottom of the bellows. The principle of the triangulation sensor operation is based on the geometric properties of the triangles. The pulses of infrared radiation come through a fiber optic cable. In order to measure the movement of the surface (the bottom of the bellows) by measuring the movement of the reflected beam, a position-sensitive detector is used, which is located in a remote controller. In this device for the intrinsic safety problem solution, optical inputs of a fiber optic flat cable are located in the active zone of the sensor, which is connected to the optical inputs of a position-sensitive detector, operated on the principles of photoelectric effect. The light spot moving along the sensitive zone and converted by the detector into a one-dimensional signal proportional to the distance to the object. hydrostatically applies pressure over the entire effective area of the measuring

Energy Efficiency Studies - Modelling and Analysis of Solar Tracker System

Solar energy is of key importance to meet the increasing demands of the electrical power needs of the society as solar energy is available in abundance, is free, clean and pollution free in nature. In order to obtain more power by increasing the receptance of incident rays from sun, a solar tracking mechanism has been developed. This paper presents an energy efficiency case study of a single-axis solar tracker which converts solar energy to electrical energy. The tracker is programmed in such a way that it gets tilted to follow sun’s movement accurately throughout the day. It was observed that the generated power output with tracking is higher in comparison to the fixed PV system. How to cite this article: Bhateja P, Gupta A, Sharam VS. Energy Efficiency Studies - Modelling and Analysis of Solar Tracker System. J Adv Res Alt Energ Env Eco 2019; 6(3&4): 1-6. DOI: https://doi.org/10.24321/2455.3093.201902

Double-wedge Sagnac lateral shearing interferometer for measuring the upper atmospheric wind field

The double-wedge Sagnac lateral shearing interferometer was put forward as a novel device for the upper atmospheric wind field measurement, and its shearing principle was presented. Using the geometrical optics, the exact expression of the optical path difference (OPD) within the range of the whole field was calculated when the incident ray with arbitrary directions arrived at the incoming plane. In order to analyze and discuss the influences of different parameters on the OPD, the computer simulations were performed for two moveable directions (the hypotenuse and right angle side) of the moving wedge prism. The OPD of the double-wedge Sagnac lateral shearing interferometer was changed by the moving wedge prism, which could enlarge the field of view be as much as possible for a specific OPD. These works provided an important theoretical guidance for improving the detecting precision of the upper atmospheric wind field, and had great practical value for the development of the double-wedge Sagnac lateral shearing interferometer apparatus.

Finite Element Model and Design of Effective Focal Panel and Receiver Tube for Solar Steam Producer

Solar energy is an excellent alternative to replace conventional energy sources. Here solar energy is converted to electrical energy using a parabolic trough and a turbine. Incident rays of solar radiation falling on the trough get reflected and concentrated on the focal length of the parabolic collector. The receiver tube is placed on this axis. The thermal fluid is made to pass inside the tube (water). The concentration of solar energy on this tube raises the temperature of water converting it to steam. Steam is made to pass through a nozzle increasing its kinetic energy. It passes to the blades of an impulse turbine where the rotor rotates, and the shaft produces mechanical energy. The turbine is connected to a generator which converts mechanical energy into electrical energy, producing power. Thermal and structural stresses are determined using FEA software Ansys Workbench for the selection of appropriate sheet and tube material.

Low-temperature chemistry induced by cosmic rays: positive and negative ion desorption from nitrile-bearing astrophysical ice analogues

ABSTRACT In cold core of dark molecular clouds, where the UV radiation from external sources is strongly attenuated, cosmic rays can induce chemical reactions on the surface of ice-covered grains promoting the ejection of the processed material to the gas phase. We report the positive and negative secondary ion emission from pure CH3CN, C2H3CN, and i-C3H7CN ices due to the bombardment of heavy ions (252Cf fission fragments), simulating the incidence of cosmic rays on to icy surfaces. The secondary ions emitted from each sample were analysed by time-of-flight mass spectrometry, using Plasma Desorption Mass Spectrometry technique. Several ionic species were identified, indicating strong fragmentation on the frozen surface. Proton-transfer processes are suggested to play a role for positive ion desorption, as evidenced by the protonated RCNH+ parent molecules and (RCN)nH+ ionic clusters. The high electron affinity of the cyano radical seems to contribute to the strong emission of CN−, as well as anions attributed to the CHmCN− fragment and (RCN)nCN− cluster series. Sputtering and desorption of ion clusters (positive and negative) induced by heavy ion bombardment are suggested to constitute a route by which new neutral or ionized molecular species may be delivered to the gas phase where thermal desorption is negligible.