Driving Factors of Urban Expansion in Peri-Urban Areas of Greater Cairo Region

Since the early 1980s, the Greater Cairo Metropolitan Region (GCMR) has witnessed a rapid urban expansion that has been mainly concentrated in the peri-urban areas (PUAs). Most of this expansion was against urban planning laws and has presented a critical challenge to the urban environment. It has also led to spatial fragmentation and loss of enormous agriculture lands. This research analyses the urban expansion in the PUAs of the GCMR, during the period (2001-2017) using GIS and remote sensing. In addition to presenting a set of driving factors of this expansion, which were extracted from the literature review and previous studies. The results of this research show that the urban expansion rate during the mentioned period reached to 461 hectares per year. Moreover, the population growth and accessibility were the most significant driving factors in the PUA of the GCR

Dye rejection membranes prepared from oxidized graphite particles

This article reports the comparison of different chemical methods to produce graphite-based particles with varying degrees of oxidation as well as graphene oxide (GO) and pristine graphite (PG). Detailed physico-chemical characterization of the resulting materials was carried out, highlighting structural differences and variable oxygen content. The particles were then used to produce supported membranes, which were tested for the rejection of three different organic dyes (Rhodamine B, Methyl Blue and Congo Red), and their performance was rationalized in terms of a combination of properties of the membranes and dyes. In particular, membranes produced using edge-oxidized graphite (EOG) showed comparable performance to those derived from GO in the removal of Congo Red, providing a promising alternative to the aforementioned

MEASURING PEDESTRIAN CATCHMENT AREA AROUND THE CAMPUS AS DEVELOPMENT CORE IN THE SUBURBS OF INDONESIA. CASE STUDY OF YOGYAKARTA’S SUBURBAN PUBLIC UNIVERSITY

Indonesia is facing a rapid population growth in urban areas, thus affecting massive expansion throughout city center. Indonesia’s way of urban development dominated by low density of land use. To pursue the successive case of developed countries that concentrating the development around the transit nodes to countermeasure the urban sprawl, we collected some suburban state universities in Indonesia and observed the possibility for higher education services to stimulate the compact growth around the campus. This research found that walkable area around campus has a different characteristic and revealed that the catchment areas are strongly depends on number of campus size and gates. In conclusion, campus has an important role to provide a walkable area around its location, and will need to be considered in the future studies and decision making steps by Indonesian city authorities

Disaster consequence mitigation and evaluation of roadside green spaces in Nanjing

The extensive layout of roadside green spaces make them important green disaster mitigation nodes in high-density areas of any city; hence, further improvements in their disaster mitigation functions would make the urban disaster prevention system more effective. In the present research, different types of roadside green spaces in the Gulou district of Nanjing were identified to establish a highly efficient urban disaster refuge green space system. A total of 35 built-up roadside green spaces were employed as the study site, and for field investigation and statistical analysis, 21 factors were selected from the aspects of spatial form, functional facilities, and surrounding environment. According to their disaster mitigation abilities, cluster analysis classified these roadside green spaces into four categories: complete type, potential type, centralized type, and broad type. Finally, by analyzing the characteristics of different types of roadside green spaces, corresponding optimization strategies were proposed. In comparison to previous investigations, our study focused on the quantitative evaluation of disaster mitigation and risk protection function of roadside green spaces. In the future, the obtained results will serve as important scientific references to the planning and construction of green spaces in high-density areas of Nanjing, China

Anomalous Lattice Vibrations of Single and Few-Layer MoS2

Molybdenum disulfide (MoS2) of single and few-layer thickness was exfoliated on SiO2/Si substrate and characterized by Raman spectroscopy. The number of S-Mo-S layers of the samples was independently determined by contact-mode atomic-force microscopy. Two Raman modes, E12g and A1g, exhibited sensitive thickness dependence, with the frequency of the former decreasing and that of the latter increasing with thickness. The results provide a convenient and reliable means for determining layer thickness with atomic-level precision. The opposite direction of the frequency shifts, which cannot be explained solely by van der Waals interlayer coupling, is attributed to Coulombic interactions and possible stacking-induced changes of the intralayer bonding. This work exemplifies the evolution of structural parameters in layered materials in changing from the 3-dimensional to the 2-dimensional regime.Comment: 14 pages, 4 figure

Synthesis of Large-Area MoS2 Atomic Layers with Chemical Vapor Deposition

Large-area MoS2 atomic layers are synthesized on SiO2 substrates by chemical vapor deposition using MoO3 and S powders as the reactants. Optical, microscopic and electrical measurements suggest that the synthetic process leads to the growth of MoS2 monolayer. The TEM images verify that the synthesized MoS2 sheets are highly crystalline.Comment: First submitted on 12-Dec-2011. Accepted in Adv. Mate

Optical properties of exfoliated MoS2 coaxial nanotubes - analogues of graphene

We report on the first exfoliation of MoS2 coaxial nanotubes. The single-layer flakes, as the result of exfoliation, represent the transition metal dichalcogenides' analogue of graphene. They show a very low degree of restacking in comparison with exfoliation of MoS2 plate-like crystals. MoS2 monolayers were investigated by means of electron and atomic force microscopies, showing their structure, and ultraviolet-visible spectrometry, revealing quantum confinement as the consequence of the nanoscale size in the z-direction

Growth of Large-Area and Highly Crystalline MoS2 Thin Layers on Insulating Substrates

The two-dimensional layer of molybdenum disulfide (MoS2) has recently attracted much interest due to its direct-gap property and potential applications in optoelectronics and energy harvesting. However, the synthetic approach to obtain high quality and large-area MoS2 atomic thin layers is still rare. Here we report that the high temperature annealing of a thermally decomposed ammonium thiomolybdate layer in the presence of sulfur can produce large-area MoS2 thin layers with superior electrical performance on insulating substrates. Spectroscopic and microscopic results reveal that the synthesized MoS2 sheets are highly crystalline. The electron mobility of the bottom-gate transistor devices made of the synthesized MoS2 layer is comparable with those of the micromechanically exfoliated thin sheets from MoS2 crystals. This synthetic approach is simple, scalable and applicable to other transition metal dichalcogenides. Meanwhile, the obtained MoS2 films are transferable to arbitrary substrates, providing great opportunities to make layered composites by stacking various atomically thin layers.Comment: manuscript submitted on 11-Dec-2011, revision submitted on 16-Feb-201

Photoelectrochemical properties of chemically exfoliated MoS2

10.1039/c3ta11633fJournal of Materials Chemistry A1318935-8941JMCA