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Item The 2005 and 2006 Eruptions Of Ol Doinyo Lengai: Assessing Deep and Shallow Processes At an Active Carbonatite Volcano Using Volatile Chemistry And Fluxes(2006-11) Fischer, Tobias; Burnard, Pete; Marty, Bernard; Palhol, Fabien; Mangasini, Frank; Shaw, A. M.960's and the oldest natrocarbonatite tuffs have been dated to 1250 years B.P.. Earlier eruptions produced phonolitic and nephelinitc lavas [1]. Since the 1960's the volcano has erupted frequently producing carbonatite lava flows. Explosive eruptions are much less frequent but have occurred in 1966, 1983 [1] and 1993 [3] producing ash, cones and natrocarbonatite tephra. In July 2005, we launched an expedition to the crater to collect gas and rock samples. On July 4, the volcano began erupting low viscosity, low T (540C) high velocity (2 m/sec) lava flows at a rate of about 0.3 m3/sec. By afternoon, the lava was flowing over the eastern crater rim. During the eruption we sampled gases from nearby hornitos at 120 and 168C, yielding pristine magmatic gases characterized by 75 mol% H2O, 22% CO2, < 1% SO2, H2S, HCl and traces of H2, He, Ar, N2, CH4 and CO. CO2-CH4-CO gas equilibrium temperatures are 580C consistent with lava flow temperatures. N2-He-Ar abundances indicate an upper mantle origin of volatiles, confirmed by isotopes [4]. SO2 flux measured by mini DOAS was low (10 t/day). CO2 fluxes calculated using CO2/SO2 are 3000 to 4000 t/day. Volatiles measured in the carbonatite lavas by SIMS show low H2O (< 0.7 wt%), high S (0.2 to 1 wt%) and Cl (0.6 to 1.4 wt%) and variable F (0.06 to 0.7 wt%). CO2 contents are 30 wt% with major and trace elements typical of natrocarbonatite lavas previously reported in [1]. The release of all CO2 (30 wt% or 20 t/day) from eruption lavas would only produce a small fraction of the measured CO2. In March 2006 eyewitnesses [3] reported the occurrence of an explosive eruption and some of us returned to the volcano on May 12. The morphology of the crater had changed and was now filled with lava 2 m deep. The central cone area had collapsed. We sampled a deposit of carbonatite ash containing accretionary lapilli suggesting water-magma or water-ash interaction. The measured SO2 flux was low (approx. 10 t/day). Our data and observations imply that 1) Ol Doinyo Lengai gases originate from the upper mantle and have equilibrium temperatures consistent with carbonatite magmas, 2) the CO2 flux measured during the eruption cannot be produced by the eruption of carbonatite lavas and additional CO2 is released from the mantle, 3) explosive eruptions (such as in 2006) may be triggered by hydromagmatic processes. Alternatively the fountain material interacted with rain at the surface.Item The 3rd International Training Course in Information Technology-based for Electric Engineering Education(2009-11) Mushi, Aviti Thadei; Justo, Jackson JohnThis is a report from the representatives of Tanzania to the Third International Training Course in Information Technology-based for Electric Engineering Education. It was held at Electronic Engineering Polytechnic Institute of Surabaya (EEPIS).Item 5.0 Building Innovation Networks in Dried Cassava Value Chain: Qualitative Evidence from Innovation Brokerage(2015) Mgumia, Athman H.; Mattee, Amon Z.; Kundi, Beatus A. T.Agricultural development in developing countries is challenged by weak innovation systems and lack of innovation capacities among key actors. Integration of agricultural innovation perspectives and value chain approach for development have made the interaction between a wide range of actors of innovation to become more complex demanding different sets of knowledge, environment and incentives. The traditional homogeneous intermediary layer of agricultural extension appeared to be ineffective to this situation. As a result the majority of smallholder farmers are facing exclusion from participating in supplying the long value chains. In countries characterized by mature innovation systems, a specialized innovation-brokering role emerged as an alternative to deal with innovation challenges in agricultural sectors (market and system failures). This study, using a case study approach, intended to offer empirical evidence of the roles of innovation brokerage implemented on cassava value chain by NGOs in the setting of developed countries and where the innovation brokerage is not recognized by the agricultural knowledge infrastructure (R&D institutions and extension services). Important outcome of this analysis was that innovation brokerage roles were crucial in agricultural innovation as it is beyond the capacity of R&D extension service. Hence, the Ministry of Agriculture Food Security and Cooperative and other relevant stakeholders should recognize the innovation brokerage roles and establish an institutional framework for its functioning within the agricultural knowledge infrastructure.Item Access Authorization and Monitoring for Web Based Resources for e-Learning System for Secondary Schools in Tanzania(2007-11) Mkocha, K.; Kissaka, M. M.; Mwinyiwiwa, Bakari M. M.This paper presents the development of a mechanism for the authorization and monitoring of data for a web based e-learning system. System data as well as the different user groups accessing the data have been defined. Constraints to use the LAMP solution stack, the UML models are coded in PHP which is embedded in the HTML. These interfaces are used as doorways through which different users, as per their role, can access and work on the system data according to their clearance. On the other hand, the administrator can see different reports, from system logs by simply pressing a button.Item Accuracy of Road Management Data Collection at Various Information Quality Levels(Department of Civil Engineering, JKUAT, 2006) Mushule, Nurdin K.A complete pavement management system contains a number of different decision-support systems which operate together with an information system. Types of decision-support systems include planning, programming, preparation and operation. Planning systems are used for strategic planning to develop long term plans for the road network as a whole whilst programming systems are used to develop medium term plans. On the other hand, preparation and operation systems are employed for project preparation and management of maintenance operations, respectively. The most detailed data is required for the operation system whilst the planning system utilises the least detailed data. This paper presents the results of a research project which was carried out in Tanzania in order to establish the loss of data accuracy as the data collection moves from very detailed level (IQLI) to a higher Information Quality Level (IQLIV). In this study two types of defects, which have been found to be predominant in Tanzania, namely cracking and potholing, were investigated. The study found that there is a significant loss in data accuracy (for potholing and cracking assessment) as the level of data detail progresses from IQLI to higher level IQLs. However, the study demonstrated that, for the network level analysis, the impact of the loss in data accuracy on the resulting first year work programme and budget estimates is not as significant.Item An Adaptive Manufacturing Resource Selection for Machined Components(2008-12) Mwinuka, Tito E.Item Adhesion and Scratch Testing of Antibiotic Loaded Poly-Lactic Acid Biocomposite Thin Films on Metallic Implants(Trans Tech Publications, 2018-10) Karacan, Ipek; Chou, Joshua; Ben-Nissan, Besim; Macha, Innocent J; Juritza, Arion; Wang, Andy H; Muller, Wolfgang H; Grossin, David; Taraschi, Valerio; Oktar, Faik N; Swain, MichaelSurface modifications have been progressively applied in order to improve the mechanical, biological and chemical properties of metallic dental and orthopedic implants. Therefore, the novel and multifunctional biocomposites coating matrices, which also consist of local and targeted drug delivery systems, are the most recent applications in the medical field. In this study, gentamicin antibiotic containing HAp bioceramics were utilized in a biodegradable poly-lactic acid thin film matrix which was applied to Ti6Al4V metallic implant surfaces. Nanoindentation and scratch test methods were applied. It was observed that, bonding between coating and the substrate is strong enough to be used in implant applications. Additionally, it was observed that the hardness and Young's Modulus values of uncoated Ti6Al4V disc were 4.3 and 125.2 GPa, respectively. However, under the same testing conditions, it was also observed that the H values (0.6-0.8GPa) and the E (50-60 GPa) values of PLA-HAp biocomposite coated samples are slightly higher than the H values (0.4-0.6 GPa) and the E values (40-50GPa) of only PLA coated sample.Item Advanced Laboratory Investigation of Axial Cyclic Loading in Silica Sands(2015) Tsuha, Cristina de H. C.; Jardine, Richard J.; Yang, Zhongxuan X.; Silva, M.; Rimoy, Siya P.This paper describes the global behaviour of and local stress conditions applying to highly instrumented cyclic laboratory model displacement pile tests conducted in a calibration chamber on medium dense Fontainebleau NE34 sand. The instrumentation provided measurements of the contact stresses on the jacked pile shaft and the local vertical, radial and circumferential stresses in the surrounding soil mass, in tests involving a range of cyclic load amplitudes. The patterns of effective stress developing on and around the pile shaft are described. The data obtained are interpreted by reference to cyclic soil element tests conducted on the same soil, as described in the parallel investigation by Aghakouchak et al (2015), reported in the same symposium. The calibration chamber experiments offer a comprehensive understanding of the cyclic degradation processes, and provide key information for improving the design of piled foundations under cyclic loading.Item Advances in Bioglass and Glass Ceramics for Biomedical Applications(Wiley, 2016-05) Ben-Nissan, Besim; Choi, Andy H.; Macha, Innocent JItem Advances in Calcium Phosphate Nanocoatings and Nanocomposites(Springer, 2013-12) Choi, Andy H.; Ben-Nissan, Besim; Conway, Richard C.; Macha, Innocent JIt is possible by using nanocomposite approach to control the strength and Young’s modulus of the composite to become close to those of human cortical or cancellous bone. This is made possible with the help of secondary substitution phases. Various materials have been applied as biomaterials and tissue regeneration materials, and the in vivo cytotoxicity and biocompatibility have been the main consideration in their use and their long-term success. This chapter aims to give a brief introduction and current applications of calcium phosphate nanocomposites as tissue engineering and as a delivery vehicle for drugs, genes, and proteins. Furthermore, the chapter will also examine the potential use of calcium phosphate nanocomposite coatings for tissue engineering scaffolds.Item Advances in the HTAG Technology and Process of Biomass(Academic Journals, 2008) John, Geoffrey R.; Wilson, Lugano; Mhilu, Cuthbert F.High Temperature Air/Steam Gasification (HTAG) is a process in which a highly preheated air/steam is utilized as the oxidizer. The HTAG process follows the developments in the High Temperature Air Combustion (HiTAC), which has shown to be superior in energy saving and pollution reduction compared to the conventional combustion technology. The preheated oxidizer provides additional energy into the gasification process that enhances thermal decomposition of the gasified solid feedstock. Consequently, the HTAG increases both the calorific value of the producer gas, and the cold gasification efficiency. In this work, the advantages of the HTAG processes is presented by considering performance influencing parameters that include materials quality, oxidizer type, equivalence ratio (ER), gasification temperature, and bed additives.Item Ageing and Axial Cyclic Loading Studies of Displacement Piles in Sands(2013) Rimoy, Siya P.An investigation is presented into the mechanisms governing both the ageing and axial cyclic loading characteristics of displacement piles in silica sands. The thesis considers first the state–of–knowledge regarding the axial capacity of displacement piles in silica sands. Three main areas of uncertainty are identified; the stress regime setup by installation, the mechanisms of ageing that lead to capacity increases with time (set-up), and the effects of axial cyclic loading. New laboratory experiments are then described that involved tests with extensively instrumented 36mm diameter Mini-Imperial College Piles (Mini-ICP) with roughened (Rcla ~3.5μm) stainless steel shafts and 600 conical tip bases, that could measure axial loads, and interface radial and shear stresses at multiple positions along their shafts. Less extensively instrumented piles with varying diameters were also tested. Ten installations were made in the 1.2m diameter, 1.5m deep Grenoble– INP calibration chamber. Fresh pluviated sand masses were formed for each installation, which were typically instrumented with multiple commercially sourced (Kyowa and TML) miniature sensors to measure radial, vertical and circumferential stresses in the sand mass during pile installation, ageing, and axial static and cyclic loading tests. Key parameters that might affect pile behaviour were then isolated and considered in turn. The interpretation links the model tests to instrumented field studies and the ageing trends established from a field database. The model piles’ axial cyclic loading responses are analysed by developing cyclic interaction diagrams which are linked to full scale tests and laboratory experiments to identify the key mechanisms governing field cyclic behaviour. The interaction diagrams provide a straight-forward screening tool for addressing axial cyclic loading in practice. Reference is made to more elaborate procedures and to the experiments’ scope for validating numerical models.Item Alternative clay bricks inspired from termite mound biomimicry(Elsevier, 2022-06) Sanga, Reuben; Kilumile, Mernad; Mohamed, FatmaAs the world is witnessing vast pollution during material production, construction and demolition processes of buildings there is a need to seek for alternative materials that will reduce the environmental impact. The present study borrows inspirations from termite’s technique to create a material for constructing a naturally cemented mound structure. The studied termite mound was built from a mix of soil particles and termites saliva containing mucopolysaccharides and cellulase enzyme that digests cellulose into beta-glucose or shorter polysaccharides and oligosaccharides. These polysaccharides are found to be a source of soil stabilization and gluing property. In the process to mimic termites’ activities clay bricks were produced from a mix of clay soil and cassava flour in a form of hot cassava paste as a source of polysaccharides at 1.5%, 3%, 4.5% and 6% weight of soil. Brick samples created presented an optimal value at 1.5% cassava flour with compressive strength higher than that of burnt clay bricks at 4.28 MPa.Item Alternative Process Flow for Underground Mining Operations: Analysis of Conceptual Transport Methods Using Discrete Event Simulation(MDPI AG, Basel, Switzerland, 2016-06-30) Greberg, Jenny; Salama, Abubakary Juma; Gustafson, Anna; Skawina, BartłomiejAs the near surface deposits are being mined out, underground mines will increasingly operate at greater depths. This will increase the challenges related to transporting materials from deeper levels to the surface. For many years, the ore and waste transportation from most deep underground mines has depended on some or all of the following: truck haulage, conveyor belts, shafts, rails, and ore pass systems. In sub-level caving, and where ore passes are used, trains operating on the main lower level transport the ore from ore passes to a crusher, for subsequent hoisting to the surface through the shaft system. In many mines, the use of the ore pass system has led to several problems related to the ore pass availability, causing production disturbances and incurred cost and time for ore pass rehabilitation. These production disturbances have an impact on the mining activities since they increase the operational costs, and lower the mine throughput. A continued dependency on rock mass transportation using ore passes will generate high capital costs for various supporting structures such as rail tracks, shaft extensions, and crushers for every new main level. This study was conducted at an existing underground mine and analyzed the transport of ore from loading areas at the lower levels up to the existing shaft points using trucks without employing ore passes. The results show that, when the costs of extending ore passes to lower levels become too great or ore passes cannot be used for production, haul trucks can be a feasible alternative method for transport of ore and waste up the ramp to the existing crusher located at the previous main level. The use of trucks will avoid installing infrastructure at the next main level and extending the ore passes to lower levels, hence reducing costs.Item Alternative process flow for underground mining operations: analysis of conceptual transport methods using discrete event simulation(MDPI, 2016-09) Greberg, Jenny; Salama, Abubakary; Gustafson, Anna; Skawina, BartlomiejAs the near surface deposits are being mined out, underground mines will increasingly operate at greater depths. This will increase the challenges related to transporting materials from deeper levels to the surface. For many years, the ore and waste transportation from most deep underground mines has depended on some or all of the following: truck haulage, conveyor belts, shafts, rails, and ore pass systems. In sub-level caving, and where ore passes are used, trains operating on the main lower level transport the ore from ore passes to a crusher, for subsequent hoisting to the surface through the shaft system. In many mines, the use of the ore pass system has led to several problems related to the ore pass availability, causing production disturbances and incurred cost and time for ore pass rehabilitation. These production disturbances have an impact on the mining activities since they increase the operational costs, and lower the mine throughput. A continued dependency on rock mass transportation using ore passes will generate high capital costs for various supporting structures such as rail tracks, shaft extensions, and crushers for every new main level. This study was conducted at an existing underground mine and analyzed the transport of ore from loading areas at the lower levels up to the existing shaft points using trucks without employing ore passes. The results show that, when the costs of extending ore passes to lower levels become too great or ore passes cannot be used for production, haul trucks can be a feasible alternative method for transport of ore and waste up the ramp to the existing crusher located at the previous main level. The use of trucks will avoid installing infrastructure at the next main level and extending the ore passes to lower levels, hence reducing costsItem An Alternative Synthesis Method for Di Calcium Phosphate (Monetite) Powders from Mediterranean Mussel (Mytilus galloprovincialis) Shells(Springer NATURE, 2013-08) Macha, Innocent J; Ozyegin, Lutfiye S; Chou, Joshua; Samur, Ramazan; Oktar, Faik N; Ben-Nissan, BesimMarine species, such as corals, sea shells and nacres, attract special interest in bioceramics field for bone graft, bone cements and drug delivery applications. Most of the marine structures are made up of pure calcium carbonate (calcite or aragonite) with a very small amount of an organic matrix. In the past the most common way to transform these structures to hydroxyapatite was hydrothermal transformation method. This current work introduces a new approach for producing fine powders of calcium phosphates from Mediterranean mussel (Mytilus galloprovincialis) shells. A comparative study was carried out to investigate the differences of these powders under only hot plate heating and hot plate heating together with ultrasonic agitation while H3PO4 was added. The temperature of the hotplate was kept constant at 80 oC and then, H3PO4 was added drop wise into the solution for 2 hrs. The mixture was then placed into an oven at 100 oC for 24 hrs. They were further calcined at 800 oC for 3 hrs. XRD, FTIR and ICP-MS were used to identify the structure and composition. It was found that the final powders were predominantly monetite, with some tricalcium phosphate as a secondary phase. This relatively simple and efficient method can be easily applied to produce calcium phosphate precursor powders for a range of biomedical applications.Item Análisis De La Interacción Cíclica Arena-Pilote Bajo Cargas Axiales En Cámara De Calibración(2015) Silva, M.; Foray, P. Y.; Tsuha, Cristina de H. C.; Yang, Zhongxuan X.; Jardine, Richard J.; Rimoy, Siya P.El análisis de la distribución de tensiones a lo largo de un pilote modelo sometido a cargas axiales estáticas y cíclicas en una cámara de calibración es presentado. Una alta instrumentación permite estudiar en detalle las interacciones a nivel de la interfaz arena/pilote. Detallamos los mecanismos que controlan el mejoramiento o degradación en la capacidad de pilotes según la amplitud y tipo de cargas cíclicas aplicadas. Se introduce un nuevo diagrama de estabilidad cíclica.Item Analyses of Deteriorating Old Masonry Buildings; Characterisation of Materials for Establishment of their Compatible Repairs(2015) Makunza, John K.; Kumaran, Senthil G.Most of the Governmental and religious building structures in Rungwe district are masonry structures built during the German East Africa period. These structures are deteriorating despite of various efforts on their repair intervention using modern cements and paints. This paper studies the types of mineral binders used, composition and physical characteristics of these in-situ mortar materials for the purpose of deciding on their appropriate compatible repair materials. Field observations and investigations, laboratory materials testing and review of the literature showed that the in-situ mortar materials constituted of sub-hydraulic lime mineral binders to natural sand (1:3) mortars. Currently there are no producers of hydraulic lime in Africa and a limited production worldwide. Mix design and analysis of locally available hydrated lime plus pozzolana natural sand (1:3) mortar material have shown compatibility in chemical and major physical properties and characteristics with the substrate in-situ hardened sub-hydraulic masonry mortars. Therefore use of these repair mortars is recommended for compatible repairs to these masonry structures and as a regional alternative to cement based materials for low rise masonry structures.Item Analysis of an Extended Field Test Database Regarding Driven Pile Ageing in Sands(2015) Rimoy, Siya P.; Jardine, Richard J.Field testing has revealed that the axial capacities of piles driven in sand can increase dramatically with age after driving. Jardine et al (2006) showed from experiments conducted in Dunkirk that the processes are affected by the history of prior loading and assembled a modest database of field cases to support the evidence from their single test site. This paper reports an extended database that is used to assess: the distinct contributions of base and shaft loads; the potential influence of loading sign (compression or tension); the effects of any prior failures; the influence of groundwater type as well as the effects of pile diameter and material. The analysis presented is informed by parallel highly instrumented model tests that were designed to explore the fundamental driving mechanisms. The findings have important implications for the re-assessment and re-use of foundations in a wide range of onshore and offshore project settings.Item Analysis of Different Techniques for Improving Performance of Flat Plate Solar Collectors for Fruits Drying(2014-06) Bakari, Ramadhani; Minja, Rwaichi J. A.; Njau, Karoli N.