scholarly journals Development of Solar Desalination Units Using Solar Concentrators or/and Internal Reflectors

2021 ◽  
Vol 12 (1) ◽  
pp. 45-61
Author(s):  
Mokhtar Mohammed ◽  
Taha Janan Mourad
Keyword(s):  
Energy Input ◽  
Climatic Conditions ◽  
The Sun ◽  
Solar Concentrator ◽  
Balance Equations ◽  
Solar Concentrators ◽  
Salty Water ◽  
Solar Desalination ◽  
Solar Distillation ◽  
The One

Solar distillation is one of the oldest and simplest technologies for desalination of salty water using renewable energy, namely solar energy, and the main problem of solar distillers is the low freshwater yield in contrast to the amount of energy input from the sun. To overcome the problem, this study develops three solar desalination units by using solar concentrators or/and internal reflectors, and compares the performance of three developed systems with the one of a conventional solar distiller under the climatic conditions of the Rabat region of Morocco. The three systems are: the solar distiller with a solar concentrator, the solar distiller with internal reflectors, and the solar distiller with a solar concentrator and internal reflectors. The energy balance equations of the systems are numerically resolved to utilize MATLAB software. The findings indicate that the utilization of the internal reflectors, the solar concentrator, and the solar concentrator and internal reflectors give better performance compared to the conventional solar distiller.

scholarly journals A Precise Algorithm for Computing Sun Position on a Satellite

2019 ◽  
Author(s):  
Tao Zheng ◽  
Fei Zheng ◽  
Xi Rui ◽  
Xiang Ji
Keyword(s):  
Coordinate System ◽  
High Precision ◽  
Pitch Angle ◽  
Azimuth Angle ◽  
Maximum Deviation ◽  
The Sun ◽  
Solar Concentrator ◽  
The Difference ◽  
The One ◽  
Right Ascension

To meet the high precision sun tracking needs of a space deployable membrane solar concentrator and other equipment, an existing algorithm for accurately computing the sun position is improved. Firstly, compared with other theories, the VSOP (variation seculaires des orbits planetaires) 87 theory is selected and adopted to obtain the sun position in the second equatorial coordinate system. Comparing the results with data of the astronomical almanac from 2015, it is found that the deviation of the apparent right ascension does not exceed 0.17 arc seconds, while that of the apparent declination does not exceed 1.2 arc seconds. Then, to eliminate the difference in the direction of the sun position with respect to the satellite caused by the size of the satellite’s orbit, a translation transform is introduced in the proposed algorithm. Finally, the proposed algorithm is applied to the orbit of the satellite designated by SJ-4 (shijian-4). Under the condition that both of the existing and improved algorithms adopt the VSOP87 theory to compute sun position in the second equatorial coordinate system, the maximum deviation of the azimuth angle on the SJ-4 is 35.19 arc seconds and the one of pitch angle is 19.93 arc seconds, when the deviation is computed by subtracting the results given by both algorithms. In summary, the proposed algorithm is more accurate than the existing one.

Dual-sensitized upconversion-assisted, triple-band absorbing luminescent solar concentrators

Nanoscale ◽  
2020 ◽  
Vol 12 (33) ◽  
pp. 17265-17271
Author(s):  
Seong Kyung Nam ◽  
Kiwon Kim ◽  
Ji-Hwan Kang ◽  
Jun Hyuk Moon
Keyword(s):  
Solar Light ◽  
Photovoltaic Systems ◽  
Solar Concentrator ◽  
Solar Concentrators ◽  
Luminescent Solar Concentrators ◽  
Luminescent Solar Concentrator ◽  
Triple Band

Luminescent solar concentrator-photovoltaic systems (LSC-PV) harvest solar light by using transparent photoluminescent plates, which is expected to be particularly useful for building-integrated PV applications.

Investigation of the natural ventilation of wind catchers with different geometries in arid region houses

2020 ◽  
Vol 14 (3) ◽  
pp. 7109-7124
Author(s):  
Nasreddine Sakhri ◽  
Younes Menni ◽  
Houari Ameur ◽  
Ali J. Chamkha ◽  
Noureddine Kaid ◽  
...  
Keyword(s):  
Arid Region ◽  
Natural Ventilation ◽  
Reduction Rate ◽  
Internal Flow ◽  
Climatic Conditions ◽  
Maximum Pressure ◽  
Ventilation Technique ◽  
Window Position ◽  
The One ◽  
Flow Velocities

The wind catcher or wind tower is a natural ventilation technique that has been employed in the Middle East region and still until nowadays. The present paper aims to study the effect of the one-sided position of a wind catcher device against the ventilated space or building geometry and its natural ventilation performance. Four models based on the traditional design of a one-sided wind catcher are studied and compared. The study is achieved under the climatic conditions of the South-west of Algeria (arid region). The obtained results showed that the front and Takhtabush’s models were able to create the maximum pressure difference (ΔP) between the windward and leeward of the tower-house system. Internal airflow velocities increased with the increase of wind speed in all studied models. For example, at Vwind = 2 m/s, the internal flow velocities were 1.7, 1.8, 1.3, and 2.5 m/s for model 1, 2, 3, and 4, respectively. However, at Vwind = 6 m/s, the internal flow velocities were 5.6, 5.5, 2.5, and 7 m/s for model 1, 2, 3, and 4, respectively. The higher internal airflow velocities are given by Takhtabush, traditional, front and middle tower models, respectively, with a reduction rate between the tower outlet and occupied space by 72, 42, 36, and 33% for the middle tower, Takhtabush, traditional tower, and the front model tower, respectively. This reduction is due to the due to internal flow resistance. The third part of the study investigates the effect of window (exist opening) position on the opposite wall. The upper, middle and lower window positions are studied and compared. The air stagnation or recirculation zone inside the ventilated space reduced from 55% with the lower window to 46% for the middle window and reached 35% for the upper window position. The Front and Takhtabush models for the one-sided wind catcher with an upper window position are highly recommended for the wind-driven natural ventilation in residential houses that are located in arid regions.

Dombey and Son

2008 ◽  
Author(s):  
Charles Dickens ◽  
Dennis Walder
Keyword(s):  
Family Relationships ◽  
The Sun ◽  
The Novel ◽  
The Earth ◽  
The Future ◽  
Original Illustrations ◽  
The One

Dombey and Son ... Those three words conveyed the one idea of Mr. Dombey's life. The earth was made for Dombey and Son to trade in, and the sun and moon were made to give them light.' The hopes of Mr Dombey for the future of his shipping firm are centred on his delicate son Paul, and Florence, his devoted daughter, is unloved and neglected. When the firm faces ruin, and Dombey's second marriage ends in disaster, only Florence has the strength and humanity to save her father from desolate solitude. This new edition contains Dickens's prefaces, his working plans, and all the original illustrations by ‘Phiz’. The text is that of the definitive Clarendon edition. It has been supplemented by a wide-ranging Introduction, highlighting Dickens's engagement with his times, and the touching exploration of family relationships which give the novel added depth and relevance.

The Tychonic Method for Calculating the Ratio between the Eccentricities of Mars

2021 ◽  
Vol 52 (2) ◽  
pp. 212-234
Author(s):  
Christián C. Carman
Keyword(s):  
The Sun ◽  
Circular Orbits ◽  
The One

In Chapter 16 of Astronomia nova, Kepler describes and applies a method for finding the parameters of what he will call the vicarious hypothesis: a model that still assumes circular orbits and an equant point, but does not assume the bisection of the eccentricity, that is, that the center of the orbit is halfway between the equant point and the Sun. The method allows Kepler to find independently both centers in a very elegant way, but its application is tedious. He confesses that he had to apply it seventy times over a period of 5 years to obtain trustable results. Years earlier, when Kepler arrived to work with Tycho, he found that Tycho and Longomontanus had rejected bisection and somehow had obtained a ratio between eccentricities that, as Kepler himself highlights, happened to be very close to the one Kepler would later find after so much effort. Kepler does not say how Tycho and Longomontanus obtained their parameters and, to the best of my knowledge, there is no single published work that attempts to answer this question. Still, it is a very interesting question to ask how they arrived at values so close to those that took so much pain for Kepler to obtain. Recently, I published a paper describing a method Tycho used for finding Saturn’s parameters. In this paper, I show that by applying this method to the data of Tychonic observations of oppositions, it is possible to arrive at parameters very close to those that we know Tycho found. In this way, I argue that this is the method Tycho applied for obtaining Mars’s parameters. The simplicity of the Tychonic method contrasts with the complexity of Kepler’s.

scholarly journals Reproductive traits and floral visitors of Aechmea distichantha plants growing in different habitats of a South American xerophytic forest

Rodriguésia ◽  
2018 ◽  
Vol 69 (2) ◽  
pp. 385-396 ◽  
Author(s):  
Rodrigo M. Freire ◽  
Ignacio M. Barberis ◽  
José L. Vesprini
Keyword(s):  
Reproductive Traits ◽  
Climatic Conditions ◽  
Similar Proportion ◽  
South American ◽  
The Sun ◽  
Carpenter Bee ◽  
Carpenter Bees ◽  
Vegetative Traits ◽  
Floral Visitors ◽  
Almost All

Abstract Aechmea distichantha, a widely-distributed facultative epiphytic bromeliad species, is present from rainforests to xerophytic forests. At its southernmost distribution (Humid Chaco) it grows in the understory and forest edges. This animal-pollinated bromeliad shows high phenotypic plasticity on its vegetative traits, but there is no information about plasticity on its reproductive traits. Infructescences from shade plants were heavier, had longer rachis, more spikelets, higher number of fruits/spikelet and higher number of seeds/fruit than those from sun plants, but they presented similar number of open flowers. The number of visitation events was similar in both habitats, but more flowers were visited in the sun than in the shade. Flowers were visited by seven species (six insects and one hummingbird). In the sun, the carpenter bee was the most frequent visitor and visited almost all flowers, whereas in the shade different species of visitors attained similar proportion of visits and number of visited flowers. Despite visitation events were similar in both habitats, plants growing in the shade set more seeds/fruit than plants growing in the sun. The higher proportion of visits accomplished by carpenter bees compared to hummingbirds is probably a consequence of the climatic conditions in the austral location of these populations.

scholarly journals Cost-effective solar concentrators based on red fluorescent Zn(ii)–salicylaldiminato complex

RSC Advances ◽  
2016 ◽  
Vol 6 (21) ◽  
pp. 17474-17482 ◽  
Author(s):  
Pierpaolo Minei ◽  
Elisabetta Fanizza ◽  
Antonio M. Rodríguez ◽  
Ana B. Muñoz-García ◽  
Paola Cimino ◽  
...  
Keyword(s):  
Zinc Complex ◽  
Red Light ◽  
Cost Effective ◽  
Solar Concentrator ◽  
Solar Concentrators ◽  
Luminescent Solar Concentrator

A red light and concentrated zinc complex embedded in PMMA yields a cost-effective and efficient luminescent solar concentrator.

scholarly journals Gamma Astrometric Measurement Experiment: testing General Relativity with a small mission

2007 ◽  
Vol 3 (S248) ◽  
pp. 290-291 ◽  
Author(s):  
A. Vecchiato ◽  
M. G. Lattanzi ◽  
M. Gai ◽  
R. Morbidelli
Keyword(s):  
General Relativity ◽  
Solar Eclipse ◽  
Galactic Center ◽  
The Sun ◽  
Measurement Experiment ◽  
The One ◽  
First Time ◽  
Bending Of Light

AbstractGAME (Gamma Astrometric Measurement Experiment) is a concept for an experiment whose goal is to measure from space the γ parameter of the Parameterized Post-Newtonian formalism, by means of a satellite orbiting at 1 AU from the Sun and looking as close as possible to its limb. This technique resembles the one used during the solar eclipse of 1919, when Dyson, Eddington and collaborators measured for the first time the gravitational bending of light. Simple estimations suggest that, possibly within the budget of a small mission, one could reach the 10−6level of accuracy with ~106observations of relatively bright stars at about 2° apart from the Sun. Further simulations show that this result could be reached with only 20 days of measurements on stars ofV≤ 17 uniformly distributed. A quick look at real star densities suggests that this result could be greatly improved by observing particularly crowded regions near the galactic center.

Effect of Solar Brightness Profiles on the Performance of Parabolic Concentrating Collectors

2009 ◽  
Author(s):  
Daniel J. Chapman ◽  
Diego A. Arias
Keyword(s):  
Analytical Methods ◽  
Meteorological Data ◽  
Uncertainty Propagation ◽  
Gaussian Function ◽  
Analytical Models ◽  
The Sun ◽  
Solar Concentrator ◽  
Optical Performance ◽  
Optical Surface ◽  
Solar Brightness

Solar brightness profiles were used to model the optical performance of a parabolic linear solar concentrator. A sensitivity analysis of the sun size on collector performance was completed using analytical methods. Ray traces were created for solar brightness profiles having circumsolar ratios from 0–40%, slope errors of the optical surface from 2–5 mrads, and angles of incidence varying from 0–60 degrees. Using typical meteorological data for two locations, the optical performance was calculated and averaged over a year. Intercept factors of these simulations were compared to simpler analytical models that cast the sun shape as a Gaussian function. Results showed that collector performance is relatively insensitive to solar profile, and that using a representative Gaussian solar profile will tend to underestimate collector performance compared to using exact weighted solar profiles by about 1%. This difference is within the uncertainty propagation of the intercept factor calculated with analytical methods.

Treatment of frostbite in an open way (without dressings)

1937 ◽  
Vol 33 (1) ◽  
pp. 84-86
Author(s):  
V. A. Petrovykh
Keyword(s):  
Recovery Period ◽  
Climatic Conditions ◽  
The Other ◽  
Critical Approach ◽  
Tatar Strait ◽  
Other Hand ◽  
Number Of Patients ◽  
The One ◽  
Apparent Similarity ◽  
Methods Of Treatment

The harsh climatic conditions of the coast of the Tatar Strait make explainable the large number of patients with frostbite who passed under our supervision during the winter of 1935-36 and amounted to 2.8% (26 people) of the total contingent of inpatients. The variety of recommended methods for treating frostbite, on the one hand, and the relatively long recovery period for all of them, on the other hand, made us take a critical approach to the proposed methods of treatment. All currently existing methods are reduced to the treatment of frostbite areas with bandages; and on the locus morbi apply indifferent or slightly disinfecting ointments, or a similar property of a powder, or wipes moistened with slightly disinfecting solutions, for example, Sol. kalii hyperm. 1: 1000. The apparent similarity of the external manifestations of frostbite and burns inspired us with the idea of ​​conducting frostbite therapy in an "open way", which has long occupied a well-deserved place in the treatment of burns.

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