The hydraulics of IDEal drip irrigation system components were analyzed under controlled laboratory conditions and the results can be applied to the design of IDEal systems. The hydraulic loss coefficient for the lateral-submain connector valves was determined based on laboratory measurements. It was found that the hydraulic loss due to friction in the lay-flat laterals can be accurately estimated with standard friction loss equations using a smaller effective diameter based on the wall thickness and inlet pressure head. The equivalent length barb loss, expressed as an equivalent length of lateral, was calculated for button emitters, as well as for micro-tubes inserted to lengths of 5 and 10 cm. It was concluded that the barb loss is essentially constant over the micro-tube insertion range of 5-10 cm. The head-discharge relationship and coefficient of manufacturer's variation of pre-punched lateral holes (without emitters), button emitters, and micro-tubes were characterized. Finally, several IDEal drip irrigation systems in the Central Rift Valley of Ethiopia were evaluated in the field. Recommendations were given for future research and improvements in the manufacturing, installation, operation, and maintenance of IDEal drip irrigation equipment.

The demand for well-located land in order to be developed for the upper-middle to high-income housing, industries, offices, retail, etc in Mbombela Local Municipality, is substantial. Within the past 10 years, Mbombela Local Municipality, has experienced an increase in residential development on welllocated land in and around its urban centres, i.e. Nelspruit, White River and Hazyview. Most of the land in and around these urban centres is privately owned, and as such, development is mainly driven by the market forces. However, there has been persistence in the peripheralisation of the poor through the government’s programme on low-cost housing delivery in Mbombela Local Municipality. The high demand of well-located land has triggered high land prices and this is one of the causes of lack of access to urban land by the poor. Despite good government policies on socio-economic integration, there seems to be no challenges on the current situation, either by government, Mbombela Local Municipality or private organisations. This research argues that the lack of access to urban land by the poor is the cause of the persistent peripheralisation through the programme of low-cost housing delivery in Mbombela Local Municipality. These urban centres (Nelspruit, White River and Hazyview) accommodate only those who have power to purchase, and thus, creates a socio-economic gap because the poor are excluded by the market forces in these areas. Since the government and Mbombela Local Municipality own less land in and around the urban centres, the market forces become the sole supply of well-located land. It is therefore imperative that government, Mbombela Local Municipality and private organisations forge a partnership with the private sector and deduce a sound strategy that will seek to address and challenge the current situation.

The construction industry is massive but not so advanced in adapting and utilizing technology. Sensors and sensing technology are critical elements that can enhance the digitalization of the construction industry. The need for low-cost sensors is rapidly increasing as the industry steps into the construction 4.0 phase. This research is an exploratory study on the potential of low-cost sensors, concentrating on the temperature and humidity sensors in the production stage of construction. The methodology used in the research is a qualitative approach consisting of literature review and interviews. The literature review identified the state of art of low-cost temperature and humidity sensors. From interviews, the constraints, adaptation factors were identified. The potential application of the low-cost temperature and humidity sensors were identified from the literatures and interviews. The conclusion of the research was that there is a knowledge gap in the field of low-cost temperature and humidity sensors. Furthermore, there is lack of adaptation of sensor technology in the production stage of the construction industry even though it has potential to improve the productivity and quality.

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To accommodate an expanding global population, a renewable raw material resource base, in conjunction with new building technologies, must be applied to the residential housing sector. Desirable characteristics of housing systems are economy, safety, environmental sustainability, durability, design flexibility and a long service life. The system should be acceptable to the end-user, consist of renewable, indigenous resources, and require a minimum investment in labor and equipment for both production and erection. The objective of this research was to develop a ready-to-assemble (RTA) framing system. Integral to the framing system is a nail plate connector, developed in this project, that laminates wood or wood composite elements into larger building components. The laminated components can be bolted together to form various structural configurations. Decisions on the development of the RTA system were structured according to an Innovation Development Decision Model (IDDP) that was constructed from previous adoption and diffusion research. The IDDP model elucidates and illustrates the innovation process from conceptual idea to product adoption. The critical issues for product acceptance include system performance in terms of safety, cost, and building code approval. The objective of the experimental portion of the research was to test the performance of the RTA connection system in specific modes and to develop a theoretical method to predict the strength of the connection. A series of experiments to quantify the shear strength and stiffness of six joint configurations assembled with the RTA connector were designed and conducted. The joints were fabricated from solid sawn lumber and three different wood-base composites. The experimental results indicated that the strength of the RTA connector in perpendicular-to-grain and parallel-to-grain orientations can be predicted from a theoretical dowel yield model. The material properties used in the yield model were adjusted for duration of load and safety. Empirical test values were within ±6.3 % of the predicted values from the theoretical model. Joint stiffness was evaluated, modeled and quantified in the linear and non-linear ranges. A structural analysis program was used to design and model a simple RTA building for realistic gravity and wind loads. The structural model was used to predict joint forces that the RTA connector must resist in-service. The computer model predictions were compared to the empirical joint test data. The results indicate that the RTA system can be designed to meet safety and serviceability criteria. A comparison between the estimated costs of a RTA building and the costs of traditional on site construction of a building of equal dimensions indicated that the RTA system is economically competitive. / Ph. D.

Providing affordable Internet access to rural populations in large developing countries to aid economic and social progress, using various non-conventional techniques has been a topic of active research recently. The main obstacle in providing fiber-optic based terrestrial Internet links to remote villages is the cost involved in laying the cable network and disproportionately low rate of return on investment due to low density of paid users. The conventional alternative to this is providing Internet access using geostationary satellite links, which can prove commercially infeasible in predominantly cost-driven rural markets in developing economies like India or China due to high access cost per user. A low-cost derivative of the conventional satellite-based Internet access system can be developed by utilizing an aging geostationary satellite nearing the end of its active life, allowing it to enter an inclined geosynchronous orbit by limiting station keeping to only east-west maneuvers to save fuel. Eliminating the need for individual satellite receiver modules by using one centrally located earth station per village and providing last mile connectivity using Wi-Fi can further reduce the access cost per user. A Ku band system design for rural India based on this concept, using an Intelsat 906 satellite is proposed in this thesis. The path of the satellite and the tracking requirements at village stations are determined. Components required for various blocks of the system are defined. Modulation schemes, FEC, data rates, number of customers to be served, link availability and outage statistics are presented. Quantitative analysis using link budgets and ITU rain models are provided. An optimized system design and a commercial deployment model are suggested which show the system is economically feasible. / Master of Science

Decent housing available to the working class in America is in very short supply. Manufactured housing could help to meet this basic need. But community groups and politicians often reject manufactured housing because they fear it will have a negative impact upon property values and the aesthetic character of their community. This thesis examines the reasons behind these fears, how the history of manufactured housing has fed into these fears and what design elements can allay these fears. Three site planning typologies are developed using the factors found in the research, that create a good neighborhood for both the residents and outside observers. The typologies inform three designs that illustrate how manufactured housing developments can be designed to fit compatibly into existing communities. / Master of Landscape Architecture

The energy absorption capacity of a series of axially crushed composite tubes fabricated from high tow count graphite fiber is compared with those of similar tubes fabricated from aerospace-grade fiber to determine the viability of considering the use of such fibers in automotive applications. To that end, graphite-epoxy tubular specimens with circular and square cross-sectional geometries; stacking sequences with ±45° fibers and with both ±45° and 0° fibers; and two different fiber types were fabricated and crushed both statically and dynamically to examine the energy absorption characteristics. The fiber types, in the form of preimpregnated tow (towpreg) from Thiokol, were Akzo Fortafil 50k fiber and aerospace-grade T300 12k fiber. Using the towpreg, sixteen tubes were filament wound on aluminum mandrels. Three specimens were cut from each of these tubes for a total of forty-eight specimens. Twenty-four of these specimens were crushed statically in a load frame and twenty-four were crushed dynamically in a drop fixture. In order to characterize the tubes and specimens, a number of measurements were taken. These measurements included length, wall thickness, cross-sectional dimensions, volume, and mass. Two important energy absorption measures were examined: the specific energy absorption (SEA) and the ratio of the peak load to the average load. The geometry had a significant effect on the energy absorption but the stacking sequence did not. It was also found that the 50k material was less effective at absorbing energy than the 12k material, but the 50k still may be acceptable. / Master of Science