Optical telescope with 3.75 ◦ field of view and pre-aperture slewing mirror with observation area of 50 ◦ ×120 ◦ for the system of observation of day time asteroids (the SODA project)

В работе предложена оптическая схема широкоугольного телескопа с полем зрения 3.75 ◦ и апертурой 30 см для космической системы обнаружения декаметровых астероидов (проект СОДА). Основная отличительная особенность телескопа - наличие предапертурного плоского зеркала, обеспечивающего область наведения 50 ◦ × 120 ◦ , время перенаведения между соседними площадками составит не более 3 с. Предложен современный КМОП детектор с мелким пикселем. В работе представлены области обзора телескопов проекта СОДА из точки Лагранжа L 1 при использовании двух, трех и четырех телескопов, кратко обсуждены преимущества и недостатки каждого из вариантов. We propose an optical scheme of a telescope with a field of view of 3.75 ◦ and 30 cm aperture for the space system for observation of decameter size asteroids (the SODA project). The main distinctive feature of this telescope is a pre-aperture flat mirror that provides an observation area of 50 ◦ ×120 ◦ and a repointing time between the adjacent fields of less than 3 s. A modern CMOS detector with a small pixel is proposed. Observable sky area when using 2, 3 and 4 telescopes are described. The advantages and disadvantages of each option are briefly discussed.

Implementation Of The Flat Beam Technology In Lighting devices Using A Flat Mirror Surface

The article discusses one of the ways to obtain a contrasting boundary between the illuminated and unlit areas of the object (illumination technology Flat Beam) in LED lighting systems using secondary optics in the form of a flat mirror surface. The results of studies of high-power LED light sources with different emitting surface areas and with three proposed options for fixing a flat mirror surface are presented. It is shown experimentally that the optical system for LED light sources in the form of a flat mirror surface allows changing the luminous intensity curve of LED light sources, converting it in a given plane from a cosine to a concentrated one. This is how the Flat Beam lighting technology is realized. Variants of the practical application of this lighting technology obtained by using a flat mirror surface with LEDs are also proposed.

Measurements of Bicarbonate in Water Containing Ocean-Level Sulfate Using a Simple Multi-Pass Optical Raman System

The concentration of dissolved inorganic carbon in the oceans at depths of a few meters to thousands of meters is a critical parameter for understanding global warming. The concentration is both pH dependent and depth dependent. Current analysis that employs pH meters must account for several other parameters, such as salinity, temperature, pressure, and the dissolved carbon’s form, carbon dioxide, bicarbonate, or carbonate. Recently, Raman spectroscopy has been used to measure these forms directly in water at ~1000 ppm, which is unfortunately insufficient for typical ocean concentrations, such as ~115 ppm bicarbonate near the surface. Here, we employed a simple multi-pass optical system, a flat mirror to reflect the laser back through the sample, and a concave mirror opposite the entrance slit that effectively doubled the laser power and the collected Raman photons, respectively. This multi-pass optical Raman system with a 1.5 W, 532 nm laser was used to measure 30 ppm bicarbonate in water that contained 2650 ppm sulfate to simulate ocean water, a bicarbonate concentration well below that near the ocean surface. Furthermore, spectral analysis employed the bicarbonate C=O symmetric stretch at 1360 cm−1 instead of the C–OH stretch at 1015 cm−1 to avoid the intense, overlapping sulfate SO4 symmetric stretch at 985 cm−1. The calculated standard deviation of ~5 ppm for the described approach suggests that accurate measurement of bicarbonate in situ is possible, which has been, heretofore, either calculated based on pH or measured in a lab.

Deterministic Approach to Achieve Full-Polarization Cloak

Achieving full-polarization (σ) invisibility on an arbitrary three-dimensional (3D) platform is a long-held knotty issue yet extremely promising in real-world stealth applications. However, state-of-the-art invisibility cloaks typically work under a specific polarization because the anisotropy and orientation-selective resonant nature of artificial materials made the σ-immune operation elusive and terribly challenging. Here, we report a deterministic approach to engineer a metasurface skin cloak working under an arbitrary polarization state by theoretically synergizing two cloaking phase patterns required, respectively, at spin-up (σ+) and spin-down (σ−) states. Therein, the wavefront of any light impinging on the cloak can be well preserved since it is a superposition of σ+ and σ− wave. To demonstrate the effectiveness and applicability, several proof-of-concept metasurface cloaks are designed to wrap over a 3D triangle platform at microwave frequency. Results show that our cloaks are essentially capable of restoring the amplitude and phase of reflected beams as if light was incident on a flat mirror or an arbitrarily predesigned shape under full polarization states with a desirable bandwidth of ~17.9%, conceiving or deceiving an arbitrary object placed inside. Our approach, deterministic and robust in terms of accurate theoretical design, reconciles the milestone dilemma in stealth discipline and opens up an avenue for the extreme capability of ultrathin 3D cloaking of an arbitrary shape, paving up the road for real-world applications.

Pembelajaran inkuiri terbimbing tentang cermin datar untuk siswa SMP

This study aims to determine the use of guided inquiry learning to understanding students' concept about image formation by flat mirror . This study uses a mixed method research of embedded experimental design. The research subject was 88 students of Private Junior High School in the city of Malang . Then, results showed that learning can improve students' understanding of the concept well ( d - effect size = 2.32 and N -gain = 0.47 ) . Penelitian ini bertujuan untuk mengetahui efektifas pembelajaran inkuiri terbimbing terhadap pemahaman konsep siswa tentang cermin datar. Penelitian ini menggunakan metode penelitian mixed method jenis embedded experimental model. Subjek penelitian sebanyak 88 siswa di salah satu SMP swasta di kota Malang. Hasil penelitian menunjukkan, pembelajaran dapat meningkatan pemahaman konsep siswa dengan baik (d-effect size = 2,32 dan N-gain 0,47).

Autonomous solar thermal system design for indirect dehydration of Aguaymanto (Physalis Peruviana L.), Junín

This paper aimed to design an autonomous indirect solar dryer, which can dehydrate the aguaymanto in a costeffective manner, yielding a quality product suitable for export from the central part highland of Peru. To complete this task, it was proposed to design a prototype of autonomous solar dryer of 100 kg per batch of aguaymanto, equipped with flat reflectors and forced air feed, and powered with photovoltaic energy. This system allows to dry aguaymanto fruit at the requirements needed for its exportation. The fryer has the following dimensions: inner dimensions of the drying chamber: bottom 0.60 m, width 1.40 m, and height 1.10 m, with additional 0.05 m for insulation. Hence, the outer measures are bottom 0.70 m, width 1.50 m, and height 1.20 m. Two solar collectors are proposed with the dimensions of each: 1.50 m wide, 2.40 m long, and 0.15 m height; 2 flat mirror reflectors are required. A 80 Wp photovoltaic panel was selected for the forced air system and process control. This solar dryer is expected to cope with the problem of post-harvest deterioration. Also, it will facilitate the export by improving product quality and providing a cost-effective technology.

Heat Conduction On Pan Using Portable Parabolic Stove With Addition Of Flat Mirror

This research aims to develop the parabolic stove with addition of some flat mirrors around the parabolic mirror. It will increase the heat transfer of conduction in the pan. The parabolic itself has around and concave shape, making it suitable for concentrating solar energy. The experimental method was carried out in this research and the test was carried out in an open space with solar radiation intensities with ranging from 169.6 W/m² to 974.4 W/m². The results of heat conduction on a pan without the addition of a flat mirror generate a 105.15 Watt, addition of one flat mirror will generate a 174.82 Watt, addition of two flat mirrors will generate a 259.24 Watt, addition of three flat mirrors will generate a 342.79 Watt and addition of four flat mirrors will generate a 412.26 Watt. The heat conduction depends on the intensity of the sun caught by the reflector. If the sun intensity decreases, the surface temperature between of the outer pan wall (T1) and the inner wall temperature (T2) will decrease too. Keywords: Heat conduction, sun intensity, parabolic stove

OPTIMALISASI PENERIMAAN INTENSITAS CAHAYA MATAHARI PADA PERMUKAAN PANEL SURYA (SOLAR CELL) MENGGUNAKAN CERMIN

Abstrak Energi surya merupakan salah satu energi yang bias dikonversi menjadi energi listrik dengan menggunakan panel surya (photovoltaic solar). Pada penelitian ini, dirancang panel surya dengan cermin datar sebagai reflektor scanning dengan empat buah reflektor pada empat sisi panel surya. Tujuan yang ingin dicapai dalam penelitian ini yaitu untuk mendapatkan keluaran panel surya yang optimal menggunakan cemin sebagai media reflektornya dan mendapatkan konfigurasi penempatan cermin untuk meningkatkan keluaran arus dan tegangan panel surya. Metode yang digunakan dalam penelitian ini adalah metode eksperimen dengan melakukan percobaan terhadap objek bahan penelitian dengan kemiringan reflektor cermin 30o, 45o, dan 60o. Dengan penambahan reflector cermin pada panel surya menyebabkan peningkatan keluaran panel surya pada pukul 12.00 Wita. Panel tanpa reflektor mengahasilkan Arus 2,1 Ampere, Tegangan 6,52 Volt. Panel reflektor 30o menghasilkan Arus 1,89 Ampere, Tegangan 6,25 Volt, Panel reflektor 45o, Arus 2,33 Ampere, Tegangan 6,15 Volt dan Panel reflektor Arus 3,02 Ampere, dan Tegangan 6,41 Volt.Kata kunci: Energi; fotovoltaik; panel surya; cermin. Abstract Solar energy is one of the energies that can be converted into electrical energy using solar panels (photovoltaic solar). In this study, a solar panel with a flat mirror as a scanning reflector was designed with four reflectors on the four sides of the solar panel. The objectives to be achieved in this study are to obtain optimal solar panel output using the mirror as a reflector medium and obtain a mirror placement configuration to increase the current and voltage output of the solar panels. The method used in this research is an experimental method by conducting experiments on the object of the research material with a mirror reflector tilt of 30o, 45o, and 60o. With the addition of a mirror reflector on the solar panel, it causes an increase in the output of the solar panel at 12.00 GMT+08. The panel without a reflector produces a current of 2.1 Ampere, a voltage of 6.52 volts. The 30o-reflector panel produces a current of 1.89 Amperes, a Voltage of 6.25 Volts, a 450 Reflector Panel, a Current of 2.33 Amperes, a Voltage of 6.15 Volts and a Current 3.02 Amperes of Reflector Panel, and a Voltage of 6.41 Volts. Keywords: Energy; photovoltaic; solar panel; mirror