Faculty of Engineering Sciences and Technology

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Accuracy Assessment Of Preliminary Index Diagrams (PIDS) From High Resolution Orthoimages In Kenya
(2017-09-25) Wayumba, Gordon
In Kenya, various types of cadastral maps are in use for land administration; the most famous being Registry Index Maps (RIMs) used in the rural areas due to their ease of production by simple surveying techniques and air survey methods. Such RIMs initially intended as a temporary measure to speed up land registration pending preparation of more accurate documents, are still in use today resulting in unreliable and lack of up to-date survey information for better land administration. This study investigates a new system that would facilitate quick production of reliable, accurate and up to-date cadastral maps for land administration through the use of high spatial resolution satellite imagery (QuickBird). Three types of data were acquired and integrated to provide a database; namely QuickBird orthoimage, orthophoto and parcel areas from the RIMs. The evaluation was made by statistically comparing parcel areas from, orthophoto (reference data), QuickBird satellite orthoimage and the official PID Area List. The study has demonstrated that the high spatial resolution satellite imagery can be used as an input for indirect land surveying methodology. Statistical analysis indicated that there was no significant difference between parcel areas from orthophoto and satellite orthoimage while there was significant difference between PID and orthophoto areas. Good results were obtained for large and medium size parcels with an average area difference of 0.3% and 1.0% respectively and 2.6% for smaller sized parcels. However, with regard to the minimum requirements for a Land Registry Index Map to be of sufficient accuracy to perform its core functions of parcel identification, boundary relocation, mutation surveys and area computation, it can be reasonably concluded that PIDs from QuickBird orthoimage at a scale of 1:5000 met these requirements.
Accuracy Assessment Of Preliminary Index Diagrams (PIDS) From High Resolution Orthoimages In Kenya
(International Journal of Scientific Research and Engineering Studies, 2015-01) Wayumba, Gordon
Abstract: In Kenya, various types of cadastral maps are in use for land administration; the most famous being Registry Index Maps (RIMs) used in the rural areas due to their ease of production by simple surveying techniques and air survey methods. Such RIMs initially intended as a temporary measure to speed up land registration pending preparation of more accurate documents, are still in use today resulting in unreliable and lack of up to-date survey information for better land administration. This study investigates a new system that would facilitate quick production of reliable, accurate and up to-date cadastral maps for land administration through the use of high spatial resolution satellite imagery (QuickBird). Three types of data were acquired and integrated to provide a database; namely QuickBird orthoimage, orthophoto and parcel areas from the RIMs. The evaluation was made by statistically comparing parcel areas from, orthophoto (reference data), QuickBird satellite orthoimage and the official PID Area List. The study has demonstrated that the high spatial resolution satellite imagery can be used as an input for indirect land surveying methodology. Statistical analysis indicated that there was no significant difference between parcel areas from orthophoto and satellite orthoimage while there was significant difference between PID and orthophoto areas. Good results were obtained for large and medium size parcels with an average area difference of 0.3% and 1.0% respectively and 2.6% for smaller sized parcels. However, with regard to the minimum requirements for a Land Registry Index Map to be of sufficient accuracy to perform its core functions of parcel identification, boundary relocation, mutation surveys and area computation, it can be reasonably concluded that PIDs from QuickBird orthoimage at a scale of 1:5000 met these requirements
Agent-based modelling of urban sanitation: informal settlements in Nairobi
(2006) Obonyo, Esther; Omenya, Alfred
During the last two decades, Nairobi in Kenya has experienced a rapid increase in its urban population. With the number of houses failing to match the increase in urban population, a number of informal settlements (slums) have mushroomed. As the population of these areas continues to increase, the inability of the local authorities to provide basic sanitation services for the urban dwellers is becoming a serious problem. The unprocessed soil water being discarded into the environment is not only adversely affecting the ecosystem; it is also creating unhygienic conditions that are conducive for the transmission of diseases in the densely populated informal settlements. A number of community-based organisations (CBOs) have undertaken various initiatives to mitigate against such problems. These organizations operate largely independently and there is no evidence of an evaluation being undertaken across the board to model the social, economical and environmental impact of the existing sanitation initiatives. This paper describes a proposed agent-based model that is aimed at doing just that. The proposed system will increase the comparative efficacy in the selected domain by modeling the values and incentives for the different organisations in various scenarios.
Analysis of Electromagnetic Field Radiation from a Rectangular Cavity-Backed Slot Antenna Using ADI-FDTD Method
(2012) Musyoki, Stephen; Ouma, Heywood A.; K’Onditi, Dominic B.O.; Nyaory, George M.
In this paper, a rectangular Cavity Backed Slot Antenna (CBSA) Model excited by a probe is investigated. The analysis is carried out using the Alternating Direction Implicit - Finite Difference Time Domain (ADI-FDTD) Method which is applied to investigate its characteristics in terms of radiation patterns and power. This is because the method is capable of providing a more accurate definition of the electromagnetic fields within the rectangular apertures, while eliminating the Courant-Friedrich-Levy (CFL) stability condition which is present in the regular Finite Difference Time Domain (FDTD) method. A cavity-backed slot antenna structure with dimensions of 14cm×22cm×30cm is analyzed with the slot and aperture measurements done at 3GHz. Results showing current distribution on the material surrounding the apertures are presented and a discussion on the physical aspects of the aperture radiation phenomenon is also presented.
Architecture and planning under different political systems
(2015-05-19) Makachia, Peter
This book was initiated at the beginning of 2013 by Sven Thiberg, the co-founder and former chairman of ARC•PEACE (International Architects/Designers/Planners for Social Respons - ibility). He then submitted an application for funding from the Swedish Association of Architects, which granted us a sum of USD 1000. This allowed us to arrange a panel debate on Architecture and Planning under Different Political Systems in connection with ARC•PEACE’s General Assembly meeting in Vienna in April 2014. (It covered travel costs for panelists with scarce resources plus some administrative costs). Later on an invitation was sent out calling on ARC•PEACE members to send contributions to this book. There was a tremendous response, resulting in no less than 15 willing authors. In order to support the contributors, an editorial committee was formed composed of: 􀀀Prof Emer Sven Thiberg, Sweden 􀀀Prof Emer Dick Urban Vestbro, Sweden 􀀀Dr Osman El Kheir, Sudan 􀀀Dr Lina Suleiman, Sweden/Palestine 􀀀 All the papers have been examined by the editorial group. In some cases chapters were sent back to the author for revision, minor corrections or shortening. In order to ensure that the papers would be presented in proper English, the Swedish/South African journalist Madi Gray was approached. We extend thanks to her for doing the valuable work of thorough corrections. We also thank Ingrid Sillén for offering to do the layout and final editing, and for offering to use her company for publishing the book, including marketing and taking care of orders. Her costs have been covered by a donation of SEK 10000 by the Head of Department of Urban Planning and Environment at KTH. The donation was made “in honour of our long-time co-worker Dick Urban”.
Architecture and planning under different political systems
(ARC, 2014) Makachia, Peter
Aspects Of Customary Land Tenure Rights In Kenya
(2017-09-25) Wayumba, Gordon
This paper argues that the imposition of Western-style land tenure system into Kenya has not killed the spirit of the customary tenure. Instead, the customary system only went underground where it continued to grow despite the overlay of statutory law that was designed to replace it. That resilience and persistence is evident in several ways; for example, available literature indicates that many communities in Kenya continue to implement customary law in a way that indicates that customary tenure provides better solution to societal problems than the western statute laws. Consequently, many communities in Kenya continue to rely on customary tenure methods to solve land disputes as they claim that western-based courts are expensive, cumbersome and the judiciary system can be compromised. This paper therefore examines the current status of customary tenure among the Kenyan communities and how it performs visa vi vis the western-based tenure systems. The paper concludes that customary tenure still provides the only meaningful framework for the organization of social and economic livelihoods in Africa; and should therefore not be extinguished but instead be restructured to fit into modern economic regimes of the 21st Century.
Auto-resonant eniotron oscillator using a magnetron type cavity
(1991) Musyoki, Stephen; Yokoo, Kuniyoshi; Sato, Nobuyuki; Ono, Shoichi
In an ideal auto-resonant eniotron oscillator (ARPO), all the electrons are able to give almost all their kinetic energy to an electromagnetic wave, resulting in a conversion efficiency of nearly 100%. However, the electric field strength required to drive a highly efficient interaction is difficult to achieve in an ordinary rectangular or circular waveguide cavity because of the low interaction coupling between electrons and the electromagnetic wave in the cavity. In this aper, we describe our investigation of an ARPO with a magnetron type cavity in lace of that above. In this cavity, the coupling becomes sufficiently strong to confirm experimentally the romising features of an ARPO. Additionally, the experiments should be useful for developing highly efficient medium-power oscillators in the microwave region. Here we resent our rocedure for designing such an experimental tube and our computer simulation results for its operational characteristics
Auto-resonant peniotron amplifier with a down tapered DC magnetic field
(Taylor & Francis, 1990-02) Musyoki, Stephen; Yokoo, Kuniyoshi; Sato, Nabuyi; Ono, Shoichi
High efficiency operation of an auto-resonant peniotron amplifier operating with a down tapered DC magnetic field is discussed and the basic design concepts for a 200 GHz experimental prototype tube are described.
Biocontainment of PCBs on flat concrete surfaces and coprecipitation of PCBs and metals in boiler chemical cleaning wastewater by microbial carbonate precipitation
(2010) Okwadha, GDO
Some industrial equipment such as electric transformers and capacitors are located in vaults and substations on flat concrete surfaces. Due to accidents, normal routine maintenance or replacements, these equipments may spill oil which may contain PCBs on these surfaces. These spills must be cleaned up in accordance with United States Environmental Protection Agency's (USEPA) guidelines. Current cleanup operations are abiotic in nature, encompassing both physical and chemical methods. These methods generate enormous amounts of impacted wastewater and solid wastes which have to be disposed of carefully at a cost. In addition, some chemicals used are harmful to both humans and other organisms. Epoxy coatings have been used to encapsulate PCBs on concrete surfaces. However, these coating systems can be ineffective because the adhesion with concrete is easily damaged by elevated temperatures causing failure of the coating system
Biocontainment of polychlorinated biphenyls (PCBs) on flat concrete surfaces by microbial carbonate precipitation
(2011) Li, Jin; Okwdha, GDO
In this study, a biosealant obtained from microbial carbonate precipitation (MCP) was evaluated as an alternative to an epoxy-coating system. A bacterium Sporosarcina pasteurii strain ATCC 11859, which metabolizes urea and precipitates calcite in a calcium-rich environment, was used in this study to generate the biosealant on a PCB-contaminated concrete surface. Concrete cylinders measuring 3 in (76.2 mm) by 6 in (152.4 mm) were made in accordance with ASTM C33 and C192 and used for this purpose. The PCB, urea, Ca2+, and bacterial cell concentrations were set at 10 ppm, 666 mM, 250 mM, and about 2.1 × 108 cells mL−1, respectively. The results indicate that the biosealed surfaces reduced water permeability by 1–5 orders of magnitude, and had a high resistance to carbonation. Since the MCP biosealant is thermally stable under temperatures of up to 840 °C, the high temperatures that normally exist in the surrounding equipment, which may contain PCB-based fluids, have no effect on the biosealed surfaces. Consequently, there is greater potential to obtain a stronger, coherent, and durable surface by MCP. No measurable amount of PCBs was detected in the permeating water, indicating that the leaching water, if any, will have a minimum impact on the surrounding environment.
Biocontainment of polychlorinated biphenyls (PCBs) on flat concrete surfaces by microbial carbonate precipitation
(2015-09-02) Okwadha, George
In this study, a biosealant obtained from microbial carbonate precipitation (MCP) was evaluated as an alternative to an epoxy-coating system. A bacterium Sporosarcina pasteurii strain ATCC 11859, which metabolizes urea and precipitates calcite in a calcium-rich environment, was used in this study to generate the biosealant on a PCB-contaminated concrete surface. Concrete cylinders measuring 3 in (76.2 mm) by 6 in (152.4 mm) were made in accordance with ASTM C33 and C192 and used for this purpose. The PCB, urea, Ca2þ, and bacterial cell concentrations were set at 10 ppm, 666 mM, 250 mM, and about 2.1 108 cells mL 1, respectively. The results indicate that the biosealed surfaces reduced water permeability by 1e5 orders of magnitude, and had a high resistance to carbonation. Since the MCP biosealant is thermally stable under temperatures of up to 840 C, the high temperatures that normally exist in the surrounding equipment, which may contain PCB-based fluids, have no effect on the biosealed surfaces. Consequently, there is greater potential to obtain a stronger, coherent, and durable surface by MCP. No measurable amount of PCBs was detected in the permeating water, indicating that the leaching water, if any, will have a minimum impact on the surrounding environment.
Bit Error Rate Performance Analysis of a Wideband Code Division Multiple Access System Model in an Indoor Environment using Convolution Coding over Additive White Gaussian Channel
(Volume 3, Issue 5 October 2014, 2014) Musyoki, Stephen; Kibet, Philip; Ombongi, Filbert
The research entails the development of a WCDMA system model in an indoor environment that transmits data over an Additive White Gaussian Noise channel. In this environment the data rate is taken as 2Mbps. The performance of this model is enhanced by employing convolution coding scheme which reduced the error rate encountered in the system. The results show that the performance of the system improves when convolution coding is implemented. The performance of QPSK is found to be better that that of 16-QAM which means that QPSK is an efficient modulation scheme but its throughput is less that of 16-QAM. Therefore, there must be a trade-off between the modulation format to be applied in a given system and the error rate generates at the receiver by that format. The convolution coding improves the power efficiency of the system when it is incorporated into the system.
Casting of semi-solid cast iron slurry using combination of cooling slope and pressurisation
(2004) Muumbo, A; Nomura, H; Takita, M
A system developed at Nagoya University combining a cooling slope, gravity pouring and pressurisation was utilised to cast components from hypoeutectic cast iron in the semi-solid state. Investigation of resulting microstructure and attendant defects was carried out, which revealed significant improvements in primary particle size refinement and globularity in components produced through semi-solid casting (SSC) when compared with normal gravity die casting (GDC) of super-heated melt. Sub-surface anomalies such as chilling tendency and skin-deep shrinkage cavities were unavoidable in components cast under pressure in a metallic mould at room temperature but, increasing the mould preheat temperature reduced the anomalies whereas increased pressurisation improved melt feeding and drastically reduced porosity attributed to gas entrapment and solidification shrinkage
The Challenge Of Sustaining Pastoralism Land Tenure System For Ecological Conservation Of The Maasai Mara
(2017-09-25) Wayumba, Gordon
In the Maasai Mara ecosystem, nomadic pastoralism remains a dominant form of land tenure where pastoralists align their livelihoods with seasonal climate variations by systematically moving their livestock to different feed locations. In recent past, nomadic pastoralism in the Maasai Mara is challenged by the concept of private property where conventional private property regimes seek to allocate individual rights to land traditionally over a fixed and well-defined areas, including group ranches. Following the period of decolonization in Africa, implementation of these programmes became popular worldwide, even in regions with arid and semi-arid climate. However, pastoralism as a tenure system persisted and conflicts soon ensured with the individual property owners; and contemporary drivers, many underpinned by climate change agenda, further complicate these tenure conflicts. Despite all the conflicts and the value of pastoralism in ecosystem conservation, spatial information about pastoralist’s tracks and migration corridors often remain undocumented. Consequently, the spatial information about pastoralism has not been incorporated in the local land information systems or land use planning. The situation is worsening as land is continuously being surveyed, demarcated and allocated for private purposes. Social and economic welfare among pastoralists has declined as it depends on the freedom to access water and grazing areas. The challenge is therefore to inventory the cattle tracks and migration corridors, and include this information in local land information system, so that it may contribute to better planning, and alleviating the problems resulting from depriving the pastoralists access to the daily and seasonal resources. This paper therefore set out to look into the changing pastoralist land tenure (and land use) regime in the Maasai Mara conservancy, in Kenya, and proposes innovative geospatial-based methodology for comprehensive documentation of the pastoralist routes as a means of understanding climate change induced migration and thereby plan how pastoralism can be better sustained for better ecological management.
Challenges of Implementing E-Learning in Kenya: A Case of Kenyan Public Universities
(2015) Tarus, John K; Gichoya, David; Muumbo, Alex M
In this paper, we discuss the challenges experienced by Kenyan public universities in implementation of e-learning and recommend possible solutions towards its successful implementation. In the last few years, most Kenyan public universities have adopted e-learning as a new approach to teaching and learning. However, the implementation challenges faced by these universities have continued to impact negatively on its effective utilization. This paper presents the findings from a survey of 148 staff of three Kenyan public universities who are currently using e-learning in blended mode approach. The purpose of this study was to investigate the challenges hindering the implementation of e-learning in Kenyan public universities. Data was collected through questionnaires, in-depth interviews and document analysis. The findings reveal that e-learning comes with some challenges that must be addressed by Kenyan public universities before successful implementation can be realized. However, the benefits and opportunities presented by e-learning far outweigh the challenges. The paper finally recommends some possible solutions that public universities could embrace towards successful implementation of e-learning.
City Culture and society
(URP, 2011-12-04) Makachia, Peter
In her century of existence, Nairobi has served as a laboratory of various housing strategies targeting the indigenous Africans and the poor. Discriminated based on racial segregation during colonisation, the poor have also been the object of post-colonial economic marginalisation. Consequently informal settlements and dweller-initiated transformations of formal housing has become their only mode of urban domicile. The paper looks at the later model and isolates the strategic policy and design choices that have guided the dwellers’ drive to transform the provided houses. The investigation uses an historical review of related literature in existing housing estates in city’s Eastlands’ District. Further, a case study of Kaloleni Rental Estate from the district was undertaken. The resultant dwellings point to informalisation leading to deterioration through use of ‘temporary’ materials and unplanned space uses in these formal schemes. The strategies based on modernist templates which ignored consultation, local cultural spatial paradigms and basic functional needs are faulted for the proliferation of these undue transformations that compromise the living environments. Further, the continued lack of tenant security in transforming dwellings has aided in the continual physical and social deterioration of neighbourhoods. The recommendations include a phased design guided densification model, socially inclusive through the incorporation of the existing dwellership and their participation.
Colour and Nutrient Removal from Textile Waste Water Using an Enhanced Fluidised Bed Bioreactor
(2011) Nzila, C; Wambua, P; Githaiga, J; Tuigong, D; Kiriamiti, HK; Kiambi, S-L; Muumbo, A
Textile waste water contains an array of chemicals with different biodegradation characteristics that often presents chronic colour and nutrient removal problems. Conventional and advanced methods commonly applied to treat textile wastewater are normally costly and require substantial investment costs. Enhanced anaerobic digestion (E.A.D) of textile wastewater, in comparison with other processes, seems to be most promising since it drastically reduces the organic and colour load of the wastewater at substantially minimised costs. This possibility offers textile industries an opportunity to cost effectively treat their effluents. This study evaluated colour and COD removal from raw textile waste water by means of an enhanced fluidised bed bioreactor. The enhancement of the bioreactor entailed pretreatment of the raw waste water using a coagulant (AlCl3) and a polyelectrolyte organic flocculant (Calflock 2900) to remove the suspended solids. The enhanced system was operated semi-continuously under laboratory conditions for 1680 hours. The fluidised bed anaerobic bioreactor was operated at a Bv of 2.6g COD/L.d and HRT of 12 hours. The enhancement process on average achieved respectively 40 ± 13 per cent and 68 per cent COD and colour removal efficiencies. The combined system on average achieved 72 ± 7per cent and 87 ± 4 per cent COD and colour removal efficiencies respectively however the bioreactor produced a low amount of biogas. The bioreactor operated without the need to discharge regularly the biological excess of sludge produced. The implementation of the combined system proved to be quite promising thus a new approach for the treatment of textile wastewater is thus proposed.
Control of Energy in Offices in Nairobi
(Nairobi University, 2012) Makachia, Peter
Heavily glazed office buildings in the Kenyan Capital City Nairobi, common in recent times does not augur well for a micro and macro architectural environment. This has a consequent negative impact on energy use in office spaces. By use of computer simulations, traditional tools and literature review glazing use in office fenestration is analysed and its implications for architectural design investigated. The results indicate a direct relationship between the variable parameters of glazing type and size, glazed opening orientation, shading devices and control of energy loads within the office spaces and the objective of human comfort in the office spaces. In conclusion it is recommended that optimum levels of glazing size and type as well as suitable glazing orientations for architectural use in office buildings in Nairobi.
Control of Energy in Offices in Nairobi
(Nairobi University, 2009) Makachia, Peter
Heavily glazed office buildings in the Kenyan Capital City Nairobi, common in recent times does not augur well for a micro and macro architectural environment. This has a consequent negative impact on energy use in office spaces. By use of computer simulations, traditional tools and literature review glazing use in office fenestration is analysed and its implications for architectural design investigated. The results indicate a direct relationship between the variable parameters of glazing type and size, glazed opening orientation, shading devices and control of energy loads within the office spaces and the objective of human comfort in the office spaces. In conclusion it is recommended that optimum levels of glazing size and type as well as suitable glazing orientations for architectural use in office buildings in Nairobi.

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