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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Environmental Natural Processes that Achieve Thermal Comfort in Multifamily Buildings in Hot Arid Regions

Moreno, Paola January 2015 (has links)
Buildings, especially in hot climates, consume a lot of energy when people want to be comfortable inside them, which translates to very expensive fees each month. The most innovative response to this problem is renewable energy, that is used, in this case, to run mechanical HVAC systems. Renewable energy is the solution for many problems, but to avoid urban heat islands when using excessive HVAC systems (powered by renewables), and to solve thermal comfort-related problems, there has to be other solution. The major challenge to find it would be to have a change of thinking process. If a building in a hot-arid region uses natural processes to emulate the functions of HVAC systems, and the proper passive strategies, then, it will provide thermal comfort to its users, diminishing the need of a mechanical system. This hypothesis will be carried out by extracting the natural processes found in a specific case in nature, applying them into a building's design, and then simulating its energy efficiency with the adequate software. There will be a comparison of the same proposed building without the natural processes, to have tangible numbers showing that these proposed strategies, in fact, work. With explanatory detailed diagrams and the energy analysis, the hypothesis could be proven correct or incorrect. The significance of this approach relies on the proximity to the natural processes that have been working in different aspects of life since the beginning of time. They have been there all the time, waiting until architects, engineers, and people in general use them, instead of making more new energy-using inventions. By having the numbers from a conventional building and the ones of the proposed building, and the right environmental diagrams, the experiment should be valid. In the near future, there should be more research focused on nature and its processes, in order to be able to reduce the use of mechanical systems, and with that, reduce the energy use and the carbon footprint.
2

Ecological Impact of Epigeal Termitaria on Vertebrates in the Tsavo Region of Southeast Kenya

Mahan, Margaret M. 01 August 2009 (has links)
Termites ecologically engineer their environment by producing termitaria (mounds) used by many other species as dens, lookouts or food sources. The role of termite mounds in biological communities is relatively unknown, despite their ubiquitous nature. I investigated their impact on vertebrates in the Tsavo region of Kenya. Through the characterization of mounds, trapping, direct observation, and collecting microclimate data, I was able to determine the importance of mounds to vertebrates. I found uniform dispersion of mounds, that soil type is correlated with the size of mounds, and that vertebrate activity increases with mound size. I also found no significant differences in overall numbers of animals and species between mound and non-mound areas. Reptiles were found at mound sites significantly more than at non-mound sites, especially the great plated lizard and short-necked skink. I determined that mounds’ microclimate is less variable than that of the ambient. More work is needed to further our understanding of termite mounds' impacts on vertebrates. This study led to discoveries of species not known to be in the area by myself or my affiliated parties.
3

How elephants utilize a miombo-wetland ecosystem in Ugalla landscape, Western Tanzania

Kalumanga, Elikana January 2015 (has links)
African elephants are ‘keystone’ species with respect to biodiversity conservation in Africa since they maintain habitats that support several animal communities by changing vegetation structure through foraging and by dispersing seeds between landscapes. Elephants are also ‘flagship’ species because, given their impressive size, they can make people sympathetic and stimulate local and international concerns for their protection. Economically, elephants contribute to national revenues as tourists are willing to pay to watch them. Despite all these factors, little is known however about elephant movement and how they utilize resources, especially in miombo-wetland ecosystems. This thesis investigates how elephants utilize resources in a miombo-wetland ecosystem in the Ugalla landscape of Western Tanzania over different protected areas containing different resource users. Using Global Positioning System (GPS) collars fitted to six elephants, it was observed that some elephant families are not confined in one protected area in the Ugalla landscape. Rather, they moved readily between different protected areas. Elephant movements were restricted to areas near the rivers, especially the Ugalla River, during the dry season and were dispersed widely during the wet season. As they move, elephants in the miombo woodlands of Ugalla selected the most abundant woody plants for browsing. Common to many woody plants, the browsed plants were short of mineral nutrients (e.g., sodium, calcium). Elephants obtained additional minerals by eating soils from certain termite mounds. Soils from termite mounds are richer in mineral elements (e.g., sodium, calcium, iron) compared to soils from the surrounding flood plain or compared to the browsed plants. However, the recorded termite mounds from which elephants eat soils were not evenly distributed in the landscape but confined mainly to the flood plains in the Ugalla Game Reserve. The Ugalla River, which is the main source of water for the elephants and other animals and also supports fishing activities by the local people in Ugalla during the dry seasons, is infested by the water hyacinth (Eichhornia crassipes). Such infestation potentially limits access to these precious surface water supplies. In addition at the regional level, the Ugalla River is among the major rivers that flow into the Lake Tanganyika which is shared by the countries of Tanzania, Burundi, Democratic Republic of Congo and Zambia. Thus, the spread of water hyacinth if left unchecked threatens to impact Lake Tanganyika, affecting many countries and ecosystem services. This thesis highlights that sustainable conservation of biodiversity in different protected areas in the Ugalla landscape requires an integrated management approach that will embrace conservation of different interrelated landscape resources required by both wildlife and the rural poor populations for their livelihoods. Regular coordinated wildlife anti-poaching patrols should be initiated across the entire Ugalla landscape because the elephants, among other wildlife, utilize different protected areas in Ugalla. Local communities should also be engaged in conservation initiatives (e.g., controlling the spread of the water hyacinth) as these directly impact local livelihoods. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Manuscript. Paper 2: Manuscript. Paper 3: Manuscript. Paper 4: Manuscript.</p> / INTEGRATED NATURAL RESOURCES MANAGEMENT

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