Optical Analysis of a New Solar Distiller with Cylindrical Surface Concentrator and Vertical Gap Evaporator

In this paper, a new solar distiller floating on ocean with cylindrical surface concentrator and vertical gap evaporator is proposed for solving the problem of freshwater shortage in islands. When the distiller is floating on ocean, the vertical gap will fill with seawater automatically due to the siphon effect of hydrophilic material. Then the seawater is heated to generate vapor when the incidence sunlight is concentrated to the gap by the cylindrical concentrator. Finally, the vapor reaches the arched transparent glass at the top of the device and condenses to produce fresh water. Optical simulation for the solar distiller is carried out to find the optimal radius of the cylindrical concentrator and the height of the vertical gap. The results indicate that when the radius and height is 6 cm and 5 cm respectively, 80% of the sunlight number within the incidence angle of 45° can be captured by the seawater in the vertical gap. The annual optical performance of the distiller is analyzed for the region within 17° north latitude. As the result, the device placed in east-west direction possesses superior performance. There are more than 10 working hours and 5 working hours in which the reception rate is more than 80% in summer solstice and winter solstice respectively. In autumnal equinox, there are more than 11 working hours with the reception rate exceeding 90%. Energy balance analysis for the whole system is carried out and the stable evaporation rate per unit solar collector area increases gently from 0.12 g/ (m2‧s) to 0.65 g/(m2‧s) when the solar irradiance increases from 500 W/m2 to 1000 W/m2.

High-Luminance Mid-Air Image Display for Outdoor Viewing by Focusing Sunlight

The mid-air image is a very powerful method for presenting computer graphics in a real environment, but it cannot be used in bright locations owing to the decrease in brightness during the imaging process. Therefore, to form a mid-air image with a high-brightness light source, a square pyramidal mirror structure was investigated, and the sunlight concentration was simulated. We simulated the tilt angle and combination angle of the condenser as parameters to calculate the luminance of the surface of a transparent liquid crystal display. The light collector was installed at 55∘ from the horizontal plane and mirror. A high level of illumination was obtained when these were laminated together at an angle of 70∘. To select a suitable diffuser, we prototyped and measured the brightness of the mid-air image with an LED lamp to simulate sunlight in three settings: summer solstice, autumnal equinox, and winter solstice. The maximum luminance of the mid-air image displayed by collecting actual sunlight was estimated to be 998.6 cd/m2. This is considerably higher than the maximum smartphone brightness to allow for outdoor viewing, and it can ensure fully compatible visibility.

Rhythms during the polar night: evidence of clock-gene oscillations in the Arctic scallop Chlamys islandica

Arctic regions are highly impacted by climate change and are characterized by drastic seasonal changes in light intensity and duration with extended periods of permanent light or darkness. Organisms use cyclic variations in light to synchronize daily and seasonal biological rhythms to anticipate cyclic variations in the environment, to control phenology and to maintain fitness. In this study, we investigated the diel biological rhythms of the Arctic scallop, Chlamys islandica , during the autumnal equinox and polar night. Putative circadian clock genes and putative light perception genes were identified in the Arctic scallop. Clock gene expression oscillated in the three tissues studied (gills, muscle, mantle edge). The oscillation of some genes in some tissues shifted from daily to tidal periodicity between the equinox and polar night periods and was associated with valve behaviour. These results are the first evidence of the persistence of clock gene expression oscillations during the polar night and might suggest that functional clockwork could entrain rhythmic behaviours in polar environments.

SANCTUARY "TEMPLE OF TIME" IN NORTHERN KHAKASSIA: MODELING LIGHT-AND-SHADOW PICTURE

The results of the study of the archaeological monument of Tagar culture (VIII-III centuries BC) "Temple of time", located in Northern Khakassia, are described. The main purpose of the study was to obtain natural scientific evidence of the monument calendar significance, as well as that its construction was performed in accordance with the light-and-dark picture during the sunrise and sunset at the equinoxes and winter solstice. To modeling the annual illumination of the monument by the Sun, azimuth orientation, geodesic measurements, and astronomical calculations were performed. In addition, in order to clarify the details, the simulation of a solar beam with a total station laser beam was applied. The modeling results were confirmed by direct observations during the autumnal equinox and winter solstice, when photographs were taken with recording of the shooting moments for subsequent astronomical calculations. As a result, the importance of astronomical research methods and direct observations on astronomically significant days of the year in the study of such archaeological objects is justified. Using astronomical calculations, it is proved that the light-and-shadow picture observed on the monument in modern times is almost identical to the light-and-shadow picture in the Tagar epoch. Suggestions have been made for using laser scanning to model a light-and-shadow picture. The monument "Temple of Time" is a unique object, it is a complex spatial structure in accordance with the illumination on astronomically significant days of the year. The direction of the main axis of the monument to the rising Sun at the winter solstice is made with an error of no more than 10, which indicates that the ancient organizers of the monument knew astronomical dates well and solved a direct problem by direct observations of the Sun. Measurements, calculations, modeling and field observations confirmed the assumptions about its calendar significance of the monument's discoverer, doctor of historical Sciences V. E. Larichev.

Genethlialogy, Katarchoscopy, and Astrological Authorities in John Tzetzes’s Allegories of the “Iliad”

In his Allegoriae Iliadis, John Tzetzes makes frequent use of contemporary astrological teachings: he references planetary aspects, transits, and the respective positions of luminaries, and several important passages of the Iliad are treated as openly astrological in nature. In Tzetzes’s poem, both life and death are decided by changing positions of stars, Alexander (Paris) is favored by Aphrodite (the planet Venus), and Hector is protected by Zeus (the planet Jupiter). The idea of royal birth (or imperial horoscope) plays an important part in Tzetzes’s exploration of the myth of Heracles, and the tropical nature of the sign of Libra, due to the sun’s entry into it at the autumnal equinox, is reflected in the (non-)efficiency of the Greek ramparts. This article considers these references to astrological lore against the wider background of the surviving Fachliteratur and thus seeks to provide insight into Tzetzes’s attitude toward astrology, and, simultaneously, into his own knowledge of the lore.

Multistatic meteor radar observations of gravity-wave–tidal interaction over southern Australia

This paper assesses the ability of a recently installed 55 MHz multistatic meteor radar to measure gravity-wave-driven momentum fluxes around the mesopause and applies it in a case study of measuring gravity wave forcing on the diurnal tide during a period following the autumnal equinox of 2018. The radar considered is in the vicinity of Adelaide, South Australia (34.9∘ S, 138.6∘ E), and consists of a monostatic radar and bistatic receiver separated by approximately 55 km. The assessment shows that the inclusion of the bistatic receiver reduces the relative uncertainty of the momentum flux estimate from about 75 % to 65 % (for a flux magnitude of ∼20 m2 s−2, 1 d's worth of integration, and for a gravity wave field synthesized from a realistic spectral model). This increase in precision appears to be entirely attributable to the increased number of meteor detections associated with the combined monostatic and bistatic receivers rather than changes in the meteors' spatial distribution. The case study reveals large modulations in the diurnal tidal amplitudes, with a maximum tidal amplitude of ∼50 m s−1 and an associated maximum zonal wind velocity of around 140 m s−1. While the observed gravity wave forcing exhibits a complex relationship with the tidal winds during this period, the components of the forcing are seen to be approximately out of phase with the tidal winds above 88 km. No clear phase relationship has been observed below 88 km.

Multistatic meteor radar observations of gravity wave-tidal interaction over Southern Australia

This paper assesses the ability of a recently-installed 55 MHz multistatic meteor radar to measure gravity wave-driven momentum fluxes around the mesopause, and applies it in a case study of measuring gravity wave forcing on the diurnal tide during a period following the autumnal equinox of 2018. The radar considered is in the vicinity of Adelaide, South Australia (34.9° S, 138.6° E) and consists of a monostatic radar and bistatic receiver separated by approximately 55 km. The assessment shows that the inclusion of the bistatic receiver reduces the relative uncertainty of the momentum flux estimate from about 75 % to 65 % (for a flux magnitude of ~ 20 m2 s−2, one day's worth of integration, and for a gravity wave field synthesized from a realistic spectral model). This increase in precision appears to be entirely attributable to the increased number of meteor detections associated with the combined monostatic and bistatic receivers, rather than changes in the meteors' spatial distribution. The case study reveals large modulations in the diurnal tidal amplitudes, with a maximum tidal amplitude of ~ 50 ms−1 and an associated maximum zonal wind velocity of around 140 ms−1. While the observed gravity wave forcing exhibits a complex relationship with the tidal winds during this period, the components of the forcing are seen to be approximately out of phase with the tidal winds above 88 km. No clear phase relationship has been observed below 88 km.

Book V. Parliament First.

Chapter I. Grande Acceptation. In the last nights of September, when the autumnal equinox is past, and grey September fades into brown October, why are the Champs Elysées illuminated; why is Paris dancing, and flinging fire-works? They are gala-nights, these last of September; Paris...

Az óravigília Peftjauneith koporsóján

According to the Graeco-Roman zodiacs, the appearance of the full moon on the day of the autumnal equinox signified the moment in the astral myth of Osiris when the god was resurrected. The paper argues that the concise version of the hour vigil on the interior surface of the lid of Peftjauneith’s coffin refers to the same mythical episode. Similarly to a few other coffins of the 26th dynasty, Peftjauneith’s composition includes a short exhortative text, a visual list of the hour goddesses, together with their names (twelve for the day, and twelve for the night), and the figure of Nut who is unusually depicted as swallowing the sun and giving birth to the moon. The even distribution of the hours points to the equinox, while the juxtaposition of the sun and the moon captures the rising of the full lunar disc. The whole scene thus refers to a detail of the hour vigil not documented elsewhere, namely, that it was ideally performed when the full moon coincided with the day of the equinox. With its setup, the hour vigil of Osiris on Peftjauneith’s coffin is a forerunner of the later Graeco-Roman zodiacs.