scholarly journals Environmental, economic and energetic benefits from implantation of several modes of solar collector movements

2021 ◽  
Vol 12 (3) ◽  
pp. 313-321
Author(s):  
Mustafa Hamad ◽  
Mhanna Obaid
Keyword(s):  
Solar System ◽  
Solar Radiation ◽  
Solar Collector ◽  
The Other ◽  
Tracking Systems ◽  
Optical Efficiency ◽  
Solar Radiation Intensity ◽  
Solar Radiation Incident ◽  
The One ◽  
East West

In this research, the performance of a moving solar system on two axes was studied, the east-west axis, this axis represents the tilt angle of the solar collector. The other movement is the surface's rotation around the perpendicular axis on the surface in the east and west directions, which in turn represents the azimuth angle of the solar collector. All possibilities for these movements were also studied, in order to reach the optimal option, which in turn depends on the importance of alication and the available space on the one hand, and the economic conditions on the other hand. The maximum value of solar radiation intensity was adopted as a guide to compare the performance of six options for tracking systems. Despite the high costs of tracking systems, they often have a positive economic return, as these systems increase the efficiency of the solar system, whether it is electric or thermal twice, the first one by increasing the intensity of the solar radiation incident on the solar collector, and the second one by increasing the optical efficiency of the solar collectors and thus increasing the overall efficiency of the device. The percentage of increase in the sixth type of solar energy is about 38% compared to the fixed mode. The minimum optical efficiency of the dual tracking mode has been found as 84%, while for fixed mode is about 48%.

A search for ‘frozen optical messages’ from extraterrestrial civilizations

2002 ◽  
Vol 1 (1) ◽  
pp. 71-73 ◽  
Author(s):  
R. Weinberger ◽  
H. Hartl
Keyword(s):  
Solar System ◽  
The Other ◽  
Physical Processes ◽  
High Quality ◽  
Sky Surveys ◽  
Systematic Examination ◽  
Other Hand ◽  
Celestial Bodies ◽  
The One

For a quarter of a century we have been engaged in a systematic examination of high-quality photographic (optical) sky surveys in the search for new celestial bodies of various kinds. It took about 5000 hours to cover the whole northern celestial hemisphere and half of the southern one. In total, about 12000 new objects were discovered. From the very beginning of our programme we also searched for objects (or groupings of them) of rather peculiar morphology. The motivation was to detect objects revealing exceptional physical processes, on the one hand, but also to discover constructions possibly created by advanced extraterrestrial civilizations (ETCs), on the other hand. A number of very peculiar objects were indeed found (these were mostly studied in detail later), but none of these appeared likely to be the product of alien masterminds. We may conclude that at least within about 10000–20000 light-years around the Solar system no highly advanced ETCs intend to reveal themselves through such objects.

scholarly journals Numerical simulation of concentrating solar collector P2CC with a small concentrating ratio

2012 ◽  
Vol 16 (suppl. 2) ◽  
pp. 471-482 ◽  
Author(s):  
Velimir Stefanovic ◽  
Sasa Pavlovic ◽  
Marko Ilic ◽  
Nenad Apostolovic ◽  
Dragan Kustrimovic
Keyword(s):  
Mathematical Model ◽  
Fluid Flow ◽  
Solar Radiation ◽  
Solar Energy ◽  
Radiation Intensity ◽  
Solar Collector ◽  
Numerical Procedure ◽  
Working Fluid ◽  
Flow Rates ◽  
Solar Radiation Intensity

Solar energy may be practically utilized directly through transformation into heat, electrical or chemical energy. A physical and mathematical model is presented, as well as a numerical procedure for predicting thermal performances of the P2CC solar concentrator. The demonstrated prototype has the reception angle of 110? at concentration ratio CR = 1.38, with the significant reception of diffuse radiation. The solar collector P2CC is designed for the area of middle temperature conversion of solar radiation into heat. The working fluid is water with laminar flow through a copper pipe surrounded by an evacuated glass layer. Based on the physical model, a mathematical model is introduced, which consists of energy balance equations for four collector components. In this paper, water temperatures in flow directions are numerically predicted, as well as temperatures of relevant P2CC collector components for various values of input temperatures and mass flow rates of the working fluid, and also for various values of direct sunlight radiation and for different collector lengths. The device which is used to transform solar energy to heat is referred to as solar collector. This paper gives numerical estimated changes of temperature in the direction of fluid flow for different flow rates, different solar radiation intensity and different inlet fluid temperatures. The increase in fluid flow reduces output temperature, while the increase in solar radiation intensity and inlet water temperature increases output temperature of water. Furthermore, the dependence on fluid output temperature is determined, along with the current efficiency by the number of nodes in the numerical calculation.

The Far Slower and More Conflict-Ridden Path to German Social Integration: Toward a Multicausal, Contextual, and Multidirectional Explanatory Framework

1999 ◽  
Vol 17 (4) ◽  
pp. 34-51 ◽  
Author(s):  
Stephen Kalberg
Keyword(s):  
Social Integration ◽  
The Other ◽  
Interaction Patterns ◽  
Explanatory Framework ◽  
The One ◽  
East West

The process of social integration between eastern and western Germans has been significantly slowed by unexpectedly severe tensions along two major axes: the tempo of life and work on the one hand, and interaction patterns on the other. Although distinct explanations for the antagonisms have been offered by easterners and westerners, they share a number of similar weaknesses: a tendency to look outward toward the putative weaknesses of “the other,” a failure to provide multidirectional and broadly multicausal explanations, and a neglect of the manner in which single factors are embedded contextually in configurations of forces. Articulating a series of arguments in opposition to all unidirectional, monocausal, and acontextual modes of analysis, and emphasizing the importance of bringing values, customs, and conventions into the debate, this study calls for an expansion of the parameters of the explanatory framework and a greater acknowledgment of the complexities of east/west social integration.

scholarly journals Editorial

2005 ◽  
Vol 4 (1) ◽  
pp. 1-2 ◽  
Author(s):  
Anja C. Anderson ◽  
Axel Brandenburg
Keyword(s):  
Solar System ◽  
Artificial Life ◽  
The Other ◽  
Extreme Conditions ◽  
The Public ◽  
The World ◽  
Earth Like Planets ◽  
The One ◽  
Astronomy And Astrophysics ◽  
Broad Interest

Astrobiology harbours a number of rather diverse disciplines combining expertise in astronomy and astrophysics, biophysics and biology, chemistry and biochemistry, geophysics and geology, as well as mathematics. The need to foster advances in astrobiology are two-fold. On the one hand, there are many scientific reasons: the discoveries of extra-solar planets which contribute to our understanding of the Solar System and the formation of Earth-like planets, the realization that life can thrive under rather extreme conditions making it more probable for life to exist elsewhere in the Solar System and beyond, and the fact that major resources are being spent in developing the technology to produce artificial life, which helps us to appreciate the range of possibilities that nature may have utilized on Earth or elsewhere. On the other hand, astrobiology touches upon some fundamental questions regarding our very existence, and it is perhaps this that attracts the broad interest of scientists and the public alike. As a result, astrobiology networks and astrobiology centres have been emerging all over the world.

Optical Performance Comparison of Six ACPCs for Concentrating Radiation on All-Glass Evacuated Solar Tubes

2015 ◽  
Vol 1092-1093 ◽  
pp. 52-58 ◽  
Author(s):  
Rui Hua Xu ◽  
Qi Chao Zhang ◽  
Run Sheng Tang
Keyword(s):  
Ray Tracing ◽  
Concentration Factor ◽  
Performance Comparison ◽  
Optical Performance ◽  
Acceptance Angle ◽  
Direct Sunlight ◽  
Optical Efficiency ◽  
The One ◽  
East West ◽  
Tracing Method

In this work, six asymmetric compound parabolic concentrators (ACPC) were designed for concentrating radiation on all-glass evacuated solar tubes (EST). The ACPCs are required to be horizontally oriented in the east-west direction and to collect direct sunlight for at least 6 hrs in any day of a year. The angular dependence of optical efficiency of six ACPCs, identical in the height of both reflectors after the higher reflector being truncated, was investigated by ray-tracing method, and the annual radiation on EST concentrated by ACPCs was estimated based on solar geometry and monthly horizontally radiation. Results shows that the ACPC designed based on “hat shaped” virtual absorber with a V-groove at the bottom of reflectors is the best in terms of the optical efficiency averaged over the acceptance angle, followed by the one designed based on “hat-shaped” absorber without a V-groove at the bottom, and the one designed based on the cover tube of EST is the worst. However, from the point of annual radiation on EST, the ACPC designed based on the cover tube is the best solution, followed by the one designed based on “ice-cream shaped” absorber and the one designed based on “hat shaped” absorber is the worst due to the smallest geometric concentration factor.

scholarly journals Reassessing the Greek National Schism of World War I: The Ideological Parameters

2019 ◽  
Vol 15 (1) ◽  
pp. 234
Author(s):  
Basil C. Gounaris ◽  
Marianna D. Christopoulos
Keyword(s):  
Nineteenth Century ◽  
World War I ◽  
German Idealism ◽  
The Other ◽  
World War ◽  
The Enlightenment ◽  
Political Choices ◽  
The One ◽  
East West ◽  
Economic Criteria

The National Schism that erupted in Greece during World War I has already been thoroughly analysed in the bibliography as a crisis of national unification, defined by geographical, political and socio economic criteria. The aim of this article is to move a step forward, to support that the National Schism might also be considered as an act in the broader and much older Greek ideological drama, that of the tantalising and incomplete “return” to the East via the European West. It is argued that the Schism, far from being a bipolar confrontation between supporters and opponents of Europe, did select from the East–West debate whatever arguments were necessary to invest military and political choices with a “deeper” meaning. Our approach focuses mostly on the rhetoric produced by the two opposing camps, the Venizelists and the anti-Venizelist block, from 1914 to 1922. It is, however, complemented by a retrospective presentation of the nineteenth-century debateover the Enlightenment and liberalism, on the one hand, and German idealism, on the other.

scholarly journals Evaluation of Global Solar Radiation Received by a Spherical Solar Collector

2012 ◽  
Vol 69 (2) ◽  
Author(s):  
Ferenc GáSPáR ◽  
Mugur BÄ‚LAN ◽  
Lorentz Já„NTSCHI ◽  
Victor ROȘ
Keyword(s):  
Solar Radiation ◽  
Flat Plate ◽  
Surface Area ◽  
Tilt Angle ◽  
Solar Collector ◽  
Global Solar Radiation ◽  
Radiation Incident ◽  
Solar Radiation Incident ◽  
Flat Plate Solar Collector ◽  
Existing Data

In the paper the global solar radiation incident on a fixed spherical solar collector is evaluated and compared to a south oriented with 46 grade tilt angle fixed flat plate solar collector. Mean daily and hourly solar radiation are calculated from existing data for Cluj-Napoca, Romania. The results show that depending on the equivalent absorbing surface area taken into account, spherical collectors can be more efficient in receiving solar radiation than flat plate collectors.

scholarly journals Walter Scott and the Islamic East: Ivanhoe and the Talisman

2018 ◽  
Vol 9 (1) ◽  
pp. 758-764
Author(s):  
Nisreen Tawfiq Yousef
Keyword(s):  
Nineteenth Century ◽  
Sir Walter Scott ◽  
The Other ◽  
Cultural Interaction ◽  
The West ◽  
Walter Scott ◽  
The One ◽  
The Relationship ◽  
East West

This paper examines representations of the Islamic East in two novels by Sir Walter Scott: Ivanhoe (1820) and The Talisman (1825). The paper’s argument is that Scott’s representations of the Islamic East seems influenced in very specific ways by dominant nineteenth-century portrayals of the East. Scott’s two novels present ambivalent depictions of the East, some of which deviate from standard patterns of representation of earlier centuries. For instance, on the one hand his novels attribute positive spiritual qualities to Saracens such as generosity, bravery and kindness to animals, while on the other, and often in the same passage, they sometimes depict Saracens as violent and atavistic. I argue that, through his various narrators and characters, Scott depicts the relationship between the Islamic East and the Christian West as a significant form of cultural interaction whereby the East is presented as complementing the West. However, Scott’s portrayal of East-West relation is complex, and it would be inaccurate to claim that this denotes total acceptance of Islamic manners, customs and perspectives. 

scholarly journals EFFECT OF SOLAR RADIATION INTENSITY ON THE VEGETATIVE GROWTH AND YIELD OF COFFEE

1969 ◽  
Vol 26 (4) ◽  
pp. 73-90
Author(s):  
J. Guiscafré Arrillaga ◽  
Luis A. Gómez
Keyword(s):  
Soil Moisture ◽  
Relative Humidity ◽  
Solar Radiation ◽  
Ecological Factors ◽  
The Other ◽  
Growth And Yield ◽  
Full Sunlight ◽  
Solar Radiation Intensity ◽  
Yearly Average ◽  
One Year

Tn this study, four ecological factors were observed: solar radiation, air temperature, relative humidity and soil moisture. Of the four, solar radiation fluctuates more than any other and undoubtedly the other threefactors are influenced by solar radiation to a great extent. 1—Solar radiation varies widely with season and year. 2—The greatest intensity takes place during the months of June to September and the lowest from November to February. 3—The greatest intensity recorded under full sunlight was 1.91 gr. cal./ min./ cm.2 and the lowest was 1.35 gr. cal./ min./ cm.2. 4—The yearly average solar radiation under full sunlight was 144,754. 40 gr. cal./ cm.2. 5—The cumulative radiation for the 3 years that lasted the experiment was 434,263.20 gr. cal./ cm.2, under full sunlight. 6—Shade regulates solar radiation making it more uniform from one year to the other. 7-As solar radiation increases, growth and yield of coffee decrease. 8—Yield, and growth of coffee were definitely higher under 1/2 and 1/3 than under 2/3 and full sunlight. 9—Statistically significant differences in yield, were not found between plots with 1/2 and 1/3 sunlight. Growth was significantly higher under 1/3 exposure. 10—Radiation, produces distinctive formative effects on coffee. Plants under full sunlight were very weak, chlorotie and poorly developed. 11—Four ecological factors were measured: solar radiation, temperature, relative humidity and soil moisture. All are affected by radiation to a great extent, but other factors as vegetation have also some effect. 12—Solar radiation is negatively correlated with yields and growth. 13—Growth and yields are positively correlated. As expected low temperature and yield are associated and soil moisture acts independently in relation to growth. 14—Plants under full sunlight accumulated greater amounts of nitrogen and potash and to a less extent of phosphorous than under any other exposure. 15—An average of 53,143.20 gram calories per square centimeter per year is the optimum cumulative solar radiation for yield and growth of coffee. This amount is obtainable under natural shade of Guaba trees (Inga Inga) planted at not less than 16 x 16 feet.

scholarly journals A Methodology for Buildings Access to Solar Radiation in Sustainable Cities

2019 ◽  
Vol 11 (23) ◽  
pp. 6596 ◽  
Author(s):  
L. M. Fernández-Ahumada ◽  
J. Ramírez-Faz ◽  
R. López-Luque ◽  
A. Márquez-García ◽  
M. Varo-Martínez
Keyword(s):  
Solar Radiation ◽  
Regression Model ◽  
Mean Value ◽  
Urban Morphology ◽  
Sustainable Cities ◽  
Energy Sustainability ◽  
Solar Radiation Incident ◽  
Solar Access ◽  
The One

The growing need to improve the environmental and energy sustainability of buildings involves the use of solar radiation incident on their surfaces. However, in cities, this task is complicated due to the constructive geometry that leads to shading between buildings. In this context, this work presents a study of solar access to the façades of buildings in cities. The methodology is based on the determination of the incident annual solar radiation in 121 significant points of each façade considering the twelve representative days of the year. To characterize the influence of the different city typologies on solar access, the urban solar coefficient is proposed. A study of two neighborhoods in Cordoba (Spain) with different urban settings have been analyzed. Specifically, two typologies of neighborhoods have been compared: one with “L-shaped” and “U-shaped blocks” and another with “Grouped blocks”. For both of them, the Urban Solar Coefficient has been calculated, obtaining a higher mean value for the neighborhood with “L-shaped” and “U-shaped blocks” (0.317) than for the one with “Grouped blocks” (0.260). Accordingly, the results show that urban morphology can influence the Urban Solar Coefficient and solar access. Finally, a regression model for each neighborhood has been obtained in order to determine the dependence of the Urban Solar Coefficient on neighborhood geometry factors.

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