Urban growth dynamics and expansion forms in 11 Tanzanian cities from 1990 to 2020

With rapid urban expansion across Tanzania,there is a need to institute steps to address factors and forms as well as impacts and challenges associated with the observed trend.This study’s aim is to use spatial urban landscape indices to analyze the spatial changes in urban forms,patterns,and rates across 11 urban centers in Tanzania over a 30-year study period(1990–2020).During the past three decades,urban lands of 11 cities and town in Tanzania have grown by a total of 480 km2.Leapfrog growth was found as the most dominant form of urban expansion in Tanzania while Dodoma,the capital city of Tanzania,had the highest rate of urban expansion when compared to all other individual cities.The most robust and significant interaction of the AWMLEI and MLEI was found in Kigoma,Arusha,Mtwara,Mafinga,and Tunduma cities.In contrast,Mbeya agricultural city,Arusha the tourist city,Tabora,and Geita Lake zone areas did show their own peculiarities revealing an interesting spatial temporal variation in rate and form of expansion.The outcome of this study reveals that the influence and management of economic and socio-cultural opportunities will be an effective tool for the determination of the rapidly expanding cities and towns of Tanzania.

Study on the Mechanism of Nanopatterning in Printed Electronics Based on Molecular Dynamics Simulation

In order to research the feasibility of using the selective adsorption principle to achieve automatic shaping of nano patterns,in this study,using the liquid gallium as the conductive ink and graphene as the printing plate surface,by changing the surface wettability of patterned areas on the nanoscale of graphene printed boards,the automatic formation of liquid gallium patterns on the graphene printed plate surface was simulated.The results indicated that liquid gallium can achieve automatic patterning on the surface of graphene patterned areas;the greater the interaction energy between gallium and carbon atoms,the clearer the pattern;gallium liquid is prone to remain in complex local positions of the pattern,making it difficult to shape the pattern;if the spacing between adjacent pattern lines is too large or too small,it will result in residual gallium liquid between the lines;increasing the thickness of the gallium film will cause the pattern to expand beyond the boundary,but increasing the thickness of the gallium film can also enhance the thickness and uniformity of the pattern lines.In summary,the principle of selective adsorption can be used to achieve the automatic formation of nano patterns,and the pattern formation effect is influenced by factors such as atomic interaction energy and pattern configuration.