Spatial rules that generate urban patterns: Emergence of the power law in the distribution of axial line length     

Hani Rezayan  Mahmoud Reza Delavar  Andrew Ulrich Frank  A. Mansouri 《International Journal of Applied Earth Observation and Geoinformation》2010

This paper studies emergence/generation of power law in rank-order distribution of axial line length, which is a global pattern observed in real cities, due to interaction of a set of seven simple spatial rules at a local scale. These rules and their interactions form a model expected to simulate the morphological structure of free spaces in unplanned organic pedestrian small cities. Effects of each of the seven rules are discussed through repeated simulations of eight possible combinations of the rules, using a bottom-up process. The results show that the rules generate environments with statistically stable rank-order distribution of axial line length that follows the power law. It means that the axial maps of the simulated environments have a scale-free hierarchical structure such that their distributions lean toward short axial lines. It also represents dominance of local spatial structure, as the model renders a faster rate of growth at a local scale while allowing a steady growth at a global scale.  相似文献   

Mapping groundwater recharge potential zones in arid region using GIS and Landsat approaches,southeast Tunisia   总被引：1，自引：0，他引：1  

Dhekra Souissi  Mohamed Haythem Msaddek  Lahcen Zouhri  Ismail Chenini  Moufida El May  Mahmoud Dlala 《水文科学杂志》2018,63(2):251-268

The rapid growth of population and agricultural and industrial activities has caused an increase in demand on the Jeffara aquifers of Gabes (southeast Tunisia). In fact, the over-pumping of this aquifer system has resulted in water-level declines ranging from 0.25 to 1 m/year during the past three decades. The aim of this study is to identify favourable artificial recharge sites of this aquifer system based on the combined use of remotely sensed data, a geographic information system (GIS), the Shuttle Radar Topography Mission (SRTM) product and a multiple criteria decision making (MCDM) technique. The delineation of artificial recharge zones shows high to moderate potential for groundwater recharge (40%) in the Gabes region, with high precision of good potential proposed sites. Recharge processes need to account for natural conditions and ecosystems.  相似文献   

Microwave‐Assisted Modification of Nanoalumina with Vitamin B3 as an Eco‐Friendly Nanosorbent for Trace Metals     

Mohamed E. Mahmoud  Amal R. Rashad  Shymaa H. Ragab  Tarek M. Abdel‐Fattah 《洁净——土壤、空气、水》2019,47(3)

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Sources of the predynastic grinding stones in the hu-semaineh region,upper Egypt,and their cultural context     

Abdel-Moneim A. Mahmoud  Kathryn A. Bard 《Geoarchaeology》1993,8(3):241-245

Grinding stones excavated at the Predynastic site of HG in Upper Egypt were analyzed, and consist of igneous rocks (rhyolite porphyry, basalt, granite) and metamorphic rocks (marble, quartzite). These rocks were brought to the site in Predynastic times (ca. 4000–3000 B. C.) from the Dokkan Volcanics located in the Wadi Hammamat, possibly as far away as 150 km. This is further evidence for the widespread exchange network that existed in Predynastic Upper Egypt. Complex economic interaction, as evidenced by artifacts excavated at HG, was a prime force as the early state evolved in Egypt. © 1993 John Wiley & Sons, Inc.  相似文献   

海洋工程试验池中风场模拟     

彭涛  杨建民  李俊 《海洋工程》2009,27(2):8-13

在考虑海洋工程装备在极端海况和运行海况下的载荷与受力,风载荷也是一个不可忽视的因素.目前物理模型试验仍是研究海洋工程结构物载荷与运动性能的重要手段,而深海结构物在水平漂移运动较大,如何在较大范围内得到满足试验要求的风场,是提高试验能力的重要问题.应用数值计算方法对大范围的风场模拟进行了分析,并进行了相应的物理实验,在此基础上对海洋工程试验的风场模拟提出了若干建议.  相似文献