scholarly journals Study of Aerodynamic Surface Roughness for Baghdad City Using Signal-Level Measurements

2019 ◽  
Vol 16 (1) ◽  
pp. 0215
Author(s):  
Haraj Et al.

Roughness length is one of the key variables in micrometeorological studies and environmental studies in regards to describing development of cities and urban environments. By utilizing the three dimensions ultrasonic anemometer installed at Mustansiriyah university, we determined the rate of the height of the rough elements (trees, buildings and bridges) to the surrounding area of the university for a radius of 1 km. After this, we calculated the zero-plane displacement length of eight sections and calculated the length of surface roughness. The results proved that the ranges of the variables above are ZH (9.2-13.8) m, Zd (4.3-8.1) m and Zo (0.24-0.48) m.

2019 ◽  
Vol 16 (1(Suppl.)) ◽  
pp. 0215
Author(s):  
Haraj Et al.

Roughness length is one of the key variables in micrometeorological studies and environmental studies in regards to describing development of cities and urban environments. By utilizing the three dimensions ultrasonic anemometer installed at Mustansiriyah university, we determined the rate of the height of the rough elements (trees, buildings and bridges) to the surrounding area of the university for a radius of 1 km. After this, we calculated the zero-plane displacement length of eight sections and calculated the length of surface roughness. The results proved that the ranges of the variables above are ZH (9.2-13.8) m, Zd (4.3-8.1) m and Zo (0.24-0.48) m.


1995 ◽  
Vol 11 (2) ◽  
pp. 133-137 ◽  
Author(s):  
Juan Fernández ◽  
Miguel A. Mateo ◽  
José Muñiz

The conditions are investigated in which Spanish university teachers carry out their teaching and research functions. 655 teachers from the University of Oviedo took part in this study by completing the Academic Setting Evaluation Questionnaire (ASEQ). Of the three dimensions assessed in the ASEQ, Satisfaction received the lowest ratings, Social Climate was rated higher, and Relations with students was rated the highest. These results are similar to those found in two studies carried out in the academic years 1986/87 and 1989/90. Their relevance for higher education is twofold because these data can be used as a complement of those obtained by means of students' opinions, and the crossing of both types of data can facilitate decision making in order to improve the quality of the work (teaching and research) of the university institutions.


2010 ◽  
Vol 14 (12) ◽  
pp. 2661-2669 ◽  
Author(s):  
J. Colin ◽  
R. Faivre

Abstract. Roughness length of land surfaces is an essential variable for the parameterisation of momentum and heat exchanges. The growing interest in the estimation of the surface turbulent flux parameterisation from passive remote sensing leads to an increasing development of models, and the common use of simple semi-empirical formulations to estimate surface roughness. Over complex surface land cover, these approaches would benefit from the combined use of passive remote sensing and land surface structure measurements from Light Detection And Ranging (LIDAR) techniques. Following early studies based on LIDAR profile data, this paper explores the use of imaging LIDAR measurements for the estimation of the aerodynamic roughness length over a heterogeneous landscape of the Heihe river basin, a typical inland river basin in the northwest of China. The point cloud obtained from multiple flight passes over an irrigated farmland area were used to separate the land surface topography and the vegetation canopy into a Digital Elevation Model (DEM) and a Digital Surface Model (DSM) respectively. These two models were then incorporated in two approaches: (i) a strictly geometrical approach based on the calculation of the plan surface density and the frontal surface density to derive a geometrical surface roughness; (ii) a more aerodynamic approach where both the DEM and DSM are introduced in a Computational Fluid Dynamics model (CFD). The inversion of the resulting 3-D wind field leads to a fine representation of the aerodynamic surface roughness. Examples of the use of these three approaches are presented for various wind directions together with a cross-comparison of results on heterogeneous land cover and complex roughness element structures.


2013 ◽  
Vol 29 (1) ◽  
pp. 35-47
Author(s):  
Claire Warden

The multi-spatial landscape of the North-West of England (Manchester–Salford and the surrounding area) provides the setting for Walter Greenwood's 1934 play Love on the Dole. Both the urban industrialized cityscape and the rural countryside that surrounds it are vital framing devices for the narrative – these spaces not simply acting as backdrops but taking on character roles. In this article Claire Warden reads the play's presentation of the North through the concept of landscape theatre, on the one hand, and Raymond Williams's city–country dialogism on the other, claiming that Love on the Dole is imbued with the revolutionary possibility that defines the very landscape in which it is set. From claustrophobic working-class kitchen to the open fields of Derbyshire, Love on the Dole has a sense of spatial ambition in which Greenwood regards all landscapes as tainted by the industrial world while maintaining their capacity to function independently. Ugliness and beauty, capitalist hegemony and socialistic hopefulness reside simultaneously in this important under-researched example of twentieth-century British theatre, thereby reflecting the ambivalent, shifting landscape of the North and producing a play that cannot be easily defined artistically or politically. Claire Warden is a Lecturer in Drama at the University of Lincoln. Her work focuses on peripheral British performances in the early to mid-twentieth century. She is the author of British Avant-Garde Theatre (Palgrave MacMillan, 2012) and is currently writing Modernist and Avant-Garde Performance: an Introduction for Edinburgh University Press, to be published in 2014.


2016 ◽  
Vol 12 (2) ◽  
pp. 135-144
Author(s):  
Norbert Horvath ◽  
Csilla Csiha

Abstract The bondability of beech (Fagus sylvatica L.) wood with a one-component polyurethane (1K PUR) structural (load-bearing) adhesive has been investigated at the Simonyi Károly Faculty at the University of West Hungary. Our trial is considered a preliminary investigation in order to set the convenient parameters of bonding for the structural gluing of beech wood. Wood samples were characterized by their oven dry density, and the surfaces to be bonded were characterized by their surface roughness and surface tension after machining. Based on our measurements, we have made a suggestion on the value of the ensemble of open time, applied quantity and pressure, pressing time, and surface preparation/surface roughness parameters which result in good bonding and a shear strength higher than 10 N/mm2. Furthermore, we investigated the penetration of the adhesive into the surface and state that one-sided adhesive application results in differing levels of penetration. In order to check the suitability of beech wood for glued laminated timber production, further investigations according to EN standards are necessary. Based upon the considerations noted above, delamination tests are already under evaluation.


2021 ◽  
Author(s):  
Laura Dietrich ◽  
Hans Christian Steen-Larsen ◽  
Cécile Agosta ◽  
Xavier Fettweis ◽  
Anne-Katrine Faber ◽  
...  

<p>Precipitation along with sublimation and deposition are the main contributors to the surface mass balance (SMB) in the accumulation area of the Greenland Ice Sheet (GrIS). However, precipitation events are rare and intermittent. In between precipitation events the surface snow continuously undergoes sublimation and deposition. Recent studies imply that these surface exchange processes influence the isotopic composition of the surface snow which is later archived as a climate record in ice cores. In order to understand the possible implications on the recorded climate signal, sublimation needs to be quantified on a local scale.</p><p>Here we present simulated SMB components for eight ice core drilling sites on the GrIS using the regional climate model MAR (Modèle Atmosphérique Régional). We validated MAR against in-situ flux observations at the East Greenland Ice Core Project site and found a high sensitivity of sublimation to the downward long wave flux and to the parameterization of the surface roughness length. We propose a surface roughness length optimized for the interior of the GrIS which is supported by our observations.</p><p>Our results show that in the GrIS accumulation area the mass turnover via sublimation and deposition can reach the same order of magnitude as precipitation. This highlights the importance of a better understanding of how the climate signal is imprinted in the surface snow isotopic composition.</p>


Author(s):  
Bernard Richards

In his 1952 paper ‘The chemical basis of morphogenesis’ Turing postulated his now famous Morphogenesis Equation. He claimed that his theory would explain why plants and animals took the shapes they did. When I joined him, Turing suggested that I might solve his equation in three dimensions, a new problem. After many manipulations using rather sophisticated mathematics and one of the first factory-produced computers in the UK, I derived a series of solutions to Turing’s equation. I showed that these solutions explained the shapes of specimens of the marine creatures known as Radiolaria, and that they corresponded very closely to the actual spiny shapes of real radiolarians. My work provided further evidence for Turing’s theory of morphogenesis, and in particular for his belief that the external shapes exhibited by Radiolaria can be explained by his reaction–diffusion mechanism. While working in the Computing Machine Laboratory at the University of Manchester in the early 1950s, Alan Turing reignited the interests he had had in both botany and biology from his early youth. During his school-days he was more interested in the structure of the flowers on the school sports field than in the games played there (see Fig. 1.3). It is known that during the Second World War he discussed the problem of phyllotaxis (the arrangement of leaves and florets in plants), and then at Manchester he had some conversations with Claude Wardlaw, the Professor of Botany in the University. Turing was keen to take forward the work that D’Arcy Thompson had published in On Growth and Form in 1917. In his now-famous paper of 1952 Turing solved his own ‘Equation of Morphogenesis’ in two dimensions, and demonstrated a solution that could explain the ‘dappling’—the black-and-white patterns—on cows. The next step was for me to solve Turing’s equation in three dimensions. The two-dimensional case concerns only surface features of organisms, such as dappling, spots, and stripes, whereas the three-dimensional version concerns the overall shape of an organism. In 1953 I joined Turing as a research student in the University of Manchester, and he set me the task of solving his equation in three dimensions. A remarkable journey of collaboration began. Turing chatted to me in a very friendly fashion.


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