https://hdl.handle.net/10646/152 2026-04-10T07:55:42Z https://hdl.handle.net/10646/3566 Investigating structural cracks for infrastructure: Case study of anonymous hospital, in Zimbabwe Matora, Tinashe; Shumba, Samson; Mushiri, Tawanda; Musiwa, Kudzie; Taaka, Dakarai; Mhizha, Stewart; Tumbare, Michael James The main objective of the research was to investigate the structural cracks for infrastructure at the anonymous Hospital in the place under study, in Zimbabwe and recommend the appropriate engineering solutions to the structural problems. The specific objectives involved conducting desk studies, geotechnical and materials investigations, investigating the structural designs for the existing infrastructure and producing the construction schedule. A reconnaissance survey was also conducted together with key informant interviews. Geotechnical tests included sieve analysis, shear strength tests, direct cone penetrometer test, chemical dispersive test and California bearing ratio test. Structural analysis and designs were also conducted to model the relevant solutions. Most of the crack widths exceeded the design limits so these are structural cracks. The soil in the vicinity of the site is classified as Clay of Intermediate Plasticity and Clay of Low Plasticity. The soil has adequate bearing capacity and the minimum foundation depth is 1.5 m for a bearing capacity of more than 100 kPa. It is concluded that the first cause of the cracks on some of the buildings were the use of weak construction material such as farm brick which would easily deform under a small load and the depth of the foundation was less than the minimum of 700 mm, which was also on weak soils. The mortar thickness was extensively huge resulting in hyaline horizontal cracks and the bearing capacity and factor of safety were inadequate resulting in foundation failure. The dispersive test also proved that the soils are sodic in nature. The bearing capacity of the soil in some areas is not adequate to carry the imposed loads. It is recommended to use reinforced strip foundations and deep foundations when constructing infrastructure at the site. Heavy duty concrete foundation underpinning is recommended for the existing buildings. The total cost for repairing the damaged infrastructure is valued at US$456 800. Conference Paper 2017-01-01T00:00:00Z https://hdl.handle.net/10646/3565 Design of a manually operated paper recycling machine Chikuku, Tauyanashe; Mushiri, Tawanda; Mombeyarara, Panashe Paper is used daily with learning institutions such as universities and schools being the main consumers. Due to its single usage it ends up being disposed hence most of the paper waste remains idle and unutilized although it is a valuable resource. Therefore, this paper explores the design of a cheap and efficient manually operated paper recycling machine. The design used integration of acquired knowledge on the recycling technology, existing manually operated and available paper recycling machines to form a cheap but efficient paper recycling machine. The benefits of the machine are not only centred on the merits of recycling paper but by the in-cooperation of the manually driving system which will also curb the high unemployment rates in developing countries. Due to the design being not 100% efficient due to the gear box, belt and chain transmission, the estimated efficiency is equal to 90% but using the 90% for design, the design power input is 450 watts and since an average person can produce 100 Watts constantly therefore 5 people are necessary to drive the machine. Conference paper 2017-01-01T00:00:00Z https://hdl.handle.net/10646/3485 Solar mini grids in Africa Chipandambira, N; Mushiri, Tawanda; Mugwindiri, K. The technological advancement in telecommunications, engineering and agriculture has made electricity access a key factor for the development of any region in the world. The African continent has remained largely undeveloped because the electrification rates are low especially in Sub-Saharan African and the lack of electricity access is most acute in the rural and peri-urban areas. This research paper investigates how the availability of electricity to the rural and peri-urban areas in Africa can help in achieving sustainable development goals. Renewable energy sources specifically solar have been identified as an alternative energy solution for the generation of electricity in remote areas through the use of solar mini-grids. As national power grid extension is capital intensive and generation of electricity using fossil fuel breeds huge operation costs and greenhouse gases. An exploration of the availability of the solar recourse in the continent and the level of abundance of the solar resource, sets solar energy as an electricity generation method which is clean, cheap and sustainable. This research paper furthermore explores the financial models that can be implemented by communities to ensure that the Solar Mini Grids are economically viable and sustainable. Conference paper 2017-05-22T00:00:00Z https://hdl.handle.net/10646/3376 Design of a bench saw cutting machine for wood with automatic braking system Mushiri, Tawanda; Masarakufa, Fortunate; Mbohwa, Charles This research paper explores the design of an automatic safety brake mechanism on a manual circular table saw machine which stops the blade from rotating when human flesh is detected in the blade proximity. Fatal injuries are occurring, human thumbs and entire hand cutting during operation when operator accidentally touches the spinning blade. It has become a matter of concern to develop the safety mechanism which can be retrofitted on old-model table saw machines used to train students at a university wood workshop. The researchers made use of capacitive proximity sensors to detect human flesh and then automatically activate the brake pawl to the rotating blade, D.C injection brake voltage which abruptly stop the running motor. The design procedure confirmed the quick release of the safety mechanism within 0.25 seconds as revealed from the simulation of circuits in Proteus software. With this design it is possible to stop the spinning blade in 0.25 seconds, before the operator touches the spinning blade and also the mechanism is adoptable to all circular saw machines (panel saw, bench saws), thus making a work-safe environment on the circular saws. Conference paper 2016-09-01T00:00:00Z