Effective Absorber Area in Semispherical Solar Collectors With Spiral Cylindrical Absorber

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Carlos Armenta-Déu
Keyword(s):  
Solar Radiation ◽  
Solar Collector ◽  
Effective Area ◽  
Geometrical Parameters ◽  
Applied Physics ◽  
Master Thesis ◽  
New Generation ◽  
New Algorithms

This paper develops an advanced methodology to determine the real contribution of the incidence solar radiation components, direct, diffuse, and reflected, onto a semispherical solar collector with spirally rolled up cylindrical absorber, as a function of the intercepted area of the solar radiation components by the collector’s receiver. Based on a previous work (2012, Study and Characterization of New Generation Semispherical Thermal Collectors, Ana Sofía Morillo Candás, Applied Physics Master, Master Thesis, UCM) in which the effective intercepted area for direct radiation was modeled, the present paper develops new algorithms for diffuse and reflected solar radiation and improves the existing one, with the aim at characterizing geometrical parameters of these types of collectors. The determination of the effective area intercepted by the receiver for the different components of the solar radiation is essential for the characterization of the collector’s thermal performance, as the energy received by the absorber depends on the type of radiation and on the effective area covered by each type.

New Algorithms for the Determination of Solar Radiation, Surface Temperature and PBL Height in CALMET

2004 ◽  
pp. 365-373
Author(s):  
G. Maffeis ◽  
R. Bellasio ◽  
J.S. Scire ◽  
M.G. Longoni ◽  
R. Bianconi ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Surface Temperature ◽  
New Algorithms

scholarly journals A Street Graph-Based Morphometric Characterization of Two Large Urban Areas

2021 ◽  
Vol 13 (3) ◽  
pp. 1025
Author(s):  
Luca Salvadori ◽  
Maria Grazia Badas ◽  
Annalisa Di Bernardino ◽  
Giorgio Querzoli ◽  
Simone Ferrari
Keyword(s):  
Aspect Ratio ◽  
Urban Areas ◽  
Accurate Determination ◽  
Geometrical Parameters ◽  
Urban Microclimate ◽  
Area Index ◽  
Planar Area ◽  
Morphometric Characterization

Urban microclimate modelling, both numerical and in the laboratory, has strong implications in many relevant health and life-style management issues e.g., in studies for assessment and forecast of air quality (for both outdoor and, as boundary conditions, indoor investigations), for thermometric trend analysis in urban zones, in cultural heritage preservation, etc. Moreover, the study of urban microclimate modelling is largely promoted and encouraged by international institutions for its implication in human health protection. In the present work, we propose and discuss an adaptive street graph-based method aimed at automatically computing the geometrical parameters adopted in atmospheric turbulent flow modelling. This method has been applied to two real cases, the Italian cities of Rome and Cagliari, and its results has been compared with the ones from traditional methods based on regular grids. Results show that the proposed method leads to a more accurate determination of the urban canyon parameters (Canyon Aspect Ratio and Building Aspect Ratio) and morphometric parameters (Planar Area Index and Frontal Area Index) compared to traditional regular grid-based methods, at least for the tested cases. Further investigations on a larger number of different urban contexts are planned to thoroughly test and validate the proposed algorithm.

Characterization of Impressed Current Technique to Model Corrosion of Reinforcement in Concrete

2020 ◽  
Vol 11 (1) ◽  
pp. 93-99
Author(s):  
Abu Zakir Morshed ◽  
Sheikh Shakib ◽  
Tanzim Jahin
Keyword(s):  
Immersion Time ◽  
Chloride Content ◽  
Engineering Science ◽  
Coastal Regions ◽  
Faraday’S Law ◽  
Current Technique ◽  
Corrosion Cell ◽  
Impressed Current

Corrosion of reinforcement is an important durability concern for the structures exposed to coastal regions. Since corrosion of reinforcement involves long periods of time, impressed current technique is usually used to accelerate the corrosion of reinforcement in laboratories. Characterization of impressed current technique was the main focus of this research,which involved determination of optimum chloride content and minimum immersion time of specimens for which the application of Faraday’s law could be efficient. To obtain optimum chloride content, the electrolytes in the corrosion cell were prepared similar to that of concrete pore solutions. Concrete prisms of 200 mm by 200 mm by 300 mm were used to determine the minimum immersion time for saturation. It was found that the optimum chloride content was 35 gm/L and the minimum immersion time for saturation was 140 hours. Accounting the results, a modified expression based on Faraday’s law was proposed to calculate weight loss due to corrosion. Journal of Engineering Science 11(1), 2020, 93-99

The Determination of Sense via Deleuze and Blanchot: Paradoxes of the Habitual, the Immemorial, and the Eternal Return

2008 ◽  
Vol 2 (2) ◽  
pp. 155-177 ◽  
Author(s):  
Eugene Brently Young
Keyword(s):  
Eternal Return

Eternal return is the paradox that accounts for the interplay between difference and repetition, a dynamic at the heart of Deleuze's philosophy, and Blanchot's approach to this paradox, even and especially through what it elides, further illuminates it. Deleuze draws on Blanchot's characterisations of difference, forgetting, and the unlivable to depict the ‘sense’ produced via eternal return, which, for Blanchot, is where repetition implicates or ‘carries’ pure difference. However, for Deleuze, difference and the unlivable are also developed by the living repetition or ‘contraction’ of habit, which results in his distinctive characterization of ‘force’, ‘levity’, and sense in eternal return.

SEM/EDS Characterization of Uncommon Metal Whiskers and Determination of Underlying Growth Mechanisms

2018 ◽  
Author(s):  
D. Basak ◽  
L. H. Ponce
Keyword(s):  
Reliability Analysis ◽  
Case Studies ◽  
Whisker Growth ◽  
Innovation Systems ◽  
Growth Mechanisms ◽  
Crystal Oscillator ◽  
Analysis Laboratory ◽  
Investigative Techniques

Abstract Two case-studies on uncommon metals whiskers, performed at the Reliability Analysis Laboratory (RAL) of Northrop Grumman Innovation Systems, are presented. The components analyzed are an Oven Controlled Crystal Oscillator (OCXO) and an Electromechanical Relay. Investigative techniques were used to determine the chemical and physical makeup of the metal whiskers and develop an understanding of the underlying effects and mechanisms that caused the conditions conducive to whisker growth.

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