Materials, Energy, Water and Environmental Sciences

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Drivers of increased soil erosion in East Africa’s agro-pastoral systems: changing interactions between the social, economic and natural domains
(Springer Berlin Heidelberg, 19-06-18) Wynants, Maarten; Kelly, Claire; Mtei, Kelvin; Munishi, Linus; Patrick, Aloyce; Rabinovich, Anna; Nasseri, Mona; Gilvear, David; Roberts, Neil; Boeckx, Pascal; Wilson, Geoff; Blake, William; Ndakidemi, Patrick
Increased soil erosion is one of the main drivers of land degradation in East Africa’s agricultural and pastoral landscapes. This wicked problem is rooted in historic disruptions to co-adapted agro-pastoral systems. Introduction of agricultural growth policies by centralised governance resulted in temporal and spatial scale mismatches with the complex and dynamic East African environment, which subsequently contributed to soil exhaustion, declining fertility and increased soil erosion. Coercive policies of land use, privatisation, sedentarisation, exclusion and marginalisation led to a gradual erosion of the indigenous social and economic structures. Combined with the inability of the new nation-states to provide many of the services necessary for (re)developing the social and economic domains, many communities are lacking key components enabling sustainable adaptation to changing internal and external shocks and pressures. Exemplary is the absence of growth in agricultural productivity and livelihood options outside of agriculture, which prohibits the absorption of an increasing population and pushes communities towards overexploitation of natural resources. This further increases social and economic pressures on ecosystems, locking agro-pastoral systems in a downward spiral of degradation. For the development and implementation of sustainable land management plans to be sustainable, authorities need to take the complex drivers of increased soil erosion into consideration. Examples from sustainable intensification responses to the demands of population increase, demonstrate that the integrity of locally adapted systems needs to be protected, but not isolated, from external pressures. Communities have to increase productivity and diversify their economy by building upon, not abandoning, existing linkages between the social, economic and natural domains. Locally adapted management practices need to be integrated in regional, national and supra-national institutions. A nested political and economic framework, wherein local communities are able to access agricultural technologies and state services, is a key prerequisite towards regional development of sustainable agro-pastoral systems that safeguard soil health, food and livelihood security.
Wastewater Treatment and other Research Initiatives with Vetiver Grass
(University of Dar es Salaam, 2003) Njau, Karoli; Mlay, H.
This paper described the role of substrate (soil) with respect to the type of macrophytes (plants) planted in the wastewater treatment in Horizontal Subsurface Flow (HSSF) Constructed wetlands (CWs). Wastewater parameters investigated include Nutrients: Phosphorus (Total Phosphorus, Ortho Phosphorus) and Nitrogen species (Total Kjeldahl Nitrogen (TKN Test)=(NH3-N + organic-N) and NH 3 -N) from the Maturation Waste Stabilization Ponds (WSP) effluent, which receives wastewater mainly of domestic nature from the University main Campus of Dar es Salaam, aimed at removing these species. Others were: BOD, COD, TSS and heavy metals from industrial effluents particularly from textile mills as well as physical parameters such as: EC, Temperature and pH. The three substrates were used: murram, granite and limestone; all locally available and of size range: 4-8mm and the two macrophytes used were: vetiver grass (vetiveria zizanioides) and common reeds (Phragmites mauritianus). Six HSSF CW cells packed with different substrates each and planted with different macrophytes, operated in parallel were used. Four cells received wastewater from the Maturation Waste Stabilization Ponds: The first cell was filled with murram and planted with vetiver grass (cell A). The remaining three cells were each filled with granite, murram and limestone respectively and planted with Phragmites mauritianus plants (cells B, C and D). The two other cells each of 1:0.6:0.3 m dimensions were used for industrial effluents treatment. One cell planted with Vetiver grass and another one with Phragmites mauritianus, both packed with limestone soil. The field experimental set-up was situated near the Waste Stabilization Ponds at the University of Dar es Salaam. The major findings of this study: Vetiver grass performed better than Phragmites mauritianus in removing of pollutants. For instance It was found from the treatment plant that: the organic removal (BOD) was on average 61.85% and 67.47% and COD of 37.9% and 46.2% for Phragmites mauritianus and Vetiver grass respectively. Compared with various reporters it was concluded this removal to be good.
Theoretical study of the structure and stability of the Na2Cl+, NaCl 2−, Na3Cl 2+, and Na2Cl 3− ions
(Springer Nature Switzerland AG., 2007-11) Pogrebnaya, Tatiana P.; Pogrebnoi, Alexander M.; Kudin, Lev S.
The geometrical parameters, normal vibration frequencies, and thermochemical characteristics of the Na2Cl+, NaCl 2−, Na3Cl 2+, and Na2Cl 3− ions in saturated vapors over sodium chloride were calculated by the ab initio methods including electron correlation. According to calculations, the Na2Cl+ and NaCl 2− triatomic ions have a linear equilibrium D ∞h configuration. The pentaatomic ions can exist in the form of the D ∞h linear isomer, C 2v planar cyclic isomer, or D 3h bipyramidal isomer. At ∼1000 K the Na3Cl 2+ and Na2Cl 3− ions exist predominantly in the form of the linear isomers. The energies and enthalpies of the ion-molecule reactions involving the above ions were calculated. The formation enthalpy of the ions Δf H 0(0 K) was determined: 230 ± 2 kJ/mol (Na2Cl+), −96 ± 4 kJ/mol (Na2Cl 3−), −616 ± 2 kJ/mol (NaCl 2−), and −935 ± 4 kJ/mol (Na2Cl 3−).
Calculation of the Thermodynamic Characteristics of Ions in Vapor over Sodium Fluoride
(Springer Nature Switzerland AG., 2008-01) Pogrebnaya, Tatiana P.; Pogrebnoi, Tatiana P.; Kudin, Lev S.
The geometric parameters, normal vibration frequencies, and thermochemical characteristics of the ions present in vapor over sodium fluoride, Na2F+, Na3F 2+, NaF 2−, and Na2F 3−, were calculated ab initio by the Hartree-Fock method and taking into account electron correlation. The main equilibrium configuration of all ions was found to be the linear configuration of D ∞h symmetry. Pentaatomic ions could also exist as two isomers, planar cyclic of C 2v symmetry and bipyramidal of D 3h symmetry. Their energies were higher than that of the D ∞h isomers, and their contents in vapor were negligibly low. The energies and enthalpies of dissociation of the ions with the elimination of the NaF molecule were calculated. The enthalpies of formation of the ions were obtained.
Innovations and Sustainability: The Case of Improved Biomass Stoves' Adoption and Use in Tanzania
(Lund, Sweden – Spring, 2009) Rwiza, Mwemezi
The adoption and continued use of improved stoves in the developing countries is of social, economic and environmental concern. In most developing countries, biomass-based energy accounts for more than 90% of all household energy consumption. It is estimated that each year indoor air pollution is responsible for the death of 1.6 million people in dwellings that are poorly ventilated – approximately one death in every 20 seconds. Recent studies are increasingly showing that black carbon, mainly from open and residential burning of biomass, is altering the reflective ability of the atmosphere and ice surfaces hence exacerbating global warming. The invention and diffusion of improved stoves in developing countries is therefore perceived as instrumental in the efforts to combat the negative effects related to the use of traditional hearths. The overall aim of this study was to explore the problems that stove users face after adoption of improved stoves and to suggest what could possibly be done to overcome those problems. In this study a total of 26 stove users, non-users and promoters in Tanzania were interviewed using semi-structured, unstructured and focused interview methods. Results indicate that, at the field level; lack of appropriate projects’ evaluation, inadequate grassroots (end-users) involvement, capability problems, as well as stoves’ own technical faults and inflexibility are highly undermining the diffusion efforts. In practice; women who are the primary users of stoves are either passively or partially involved in the diffusion process. At the policy-making level; the government is yet to make stove programs a priority and has settled for the NGO-led dissemination efforts. Results from this study will be a useful contribution for researchers, policy makers, NGOs and groups involved in promoting the adoption and use of more sustainable innovations.
Manufacturing of Functionally Graded Porous Products by Selective Laser Sintering
(Scientific.Net, 2009-10) Erdala, M.; Dagb, S.; Jande, Yusufu; Tekind, C.M.
Selective laser sintering (SLS) is a rapid prototyping technique which is used to manufacture plastic and metal models. The porosity of the final product obtained by SLS can be controlled by changing the energy density level used during the manufacturing process. The energy density level is itself dependent upon manufacturing parameters such as laser power, hatching distance and scanning speed. Through mechanical characterization techniques, it is possible to quantitatively relate the energy density levels to particular strength values. The present study is directed towards manufacturing functionally graded polyamide products by changing the energy density level in a predetermined manner. The mechanical properties of the functionally graded components are characterized by means of tensile testing. Both homogeneous and functionally graded specimens are produced and tested in order to examine the influence of the energy density level on the mechanical response and on the ultimate tensile and rupture strengths. Selective laser sintering is shown to possess the potential to produce functionally graded porous specimens with controlled variations in physical and mechanical properties.
Structural and thermodynamic characteristics of ionic associates in vapors over sodium bromide and iodide
(Nature Switzerland AG., 2010-05-16) Pogrebnaya, Tatiana P.; Pogrebnoi, Alexander M.; Kudin, Lev S.
Nonempirical methods are used to calculate the geometric parameters, the frequencies of normal vibrations, and thermochemical characteristics of ions existing in saturated vapors over sodium bromide and iodide: Na2X+, NaX 2−, Na3X 2+, and Na2X 3− (X = Br, I). According to the calculations, Na2X+ and NaX 2− triatomic ions have a linear equilibrium configuration of D ∞h symmetry. Pentaatomic ions can exist in the form of three isomers: linear with D ∞h symmetry, planar cyclic with C 2v symmetry, and bipyramidal with D 3h symmetry. At a temperature of ∼1000 K, Na3X 2+ and NaX 3− pentaatomic ions are shown to be present in vapor mainly in the form of linear isomers. The energies and enthalpies of ion molecular reactions with the participation of the above ions are calculated, and the formation enthalpies of the ions are determined, Δ f H o(0 K): 293±2 kJ/mol (Na2Br+), 354±2 kJ/mol (Na2I+), −536±2 kJ/mol (NaBr 2−, −458±2 kJ/mol (NaI 2−, 24±5 kJ/mol (Na3Br 2+, 143±5 kJ/mol (Na3I 2+, −810±5 kJ/mol (Na2Br 3−, and −675±5 kJ/mol (Na2I 3−.
Small Scale Fisheries Management: Lessons from Cockle Harvesters in Nicaragua and Tanzania
(Taylor & Francis Online, 2010-06-01) Crawford, Brian; Herrera, Maria D.; Herrera, Herrera; Leclair, Carlos Rivas; Jiddawi, Narriman; Semba, Masumbuko; Haws, Maria
The role of women in gleaning fisheries tends to be underestimated and poorly documented although they play an important role in coastal food security and income generation. This article describes two initiatives for co-management of women dominated cockle (Anadara spp.) fisheries implemented in Zanzibar Island of Tanzania and in Nicaragua that were based on a Fiji model. In each case, significant progress was made at the pilot scale but required adaptation to the community and national context. The Nicaragua case resulted in increasing densities of cockles inside and outside small scale no-take zones in a small estuary after a two-year period of implementation. In Zanzibar, out of several no-take sites established on reef flats, only one showed similar results. Other sites’ poor performance is likely due to poor site selection, small size, and non-compliance. Varying degrees of poaching affected both locations and continues to be an issue. In Zanzibar, local and national government played highly supporting roles whereas in Nicaragua, local government was supportive but national government continues to exhibit top-down decision-making, while still evaluating the alternative co-management approach. In both cases, university extension initiatives were influential in building community capacity for management and playing an advocacy role with national government. Both locations are poised for scaling up to more geographic sites as well as fostering policy change that can lead to more integrated and ecosystem-scale approaches to sustainable fisheries management.
Influence of aging conditions on textural properties of water-glass-based silica aerogels prepared at ambient pressure
(Springer US, 2010-06-04) Sarawade, Pradip Bhikaji; Kim, Jong-Kil; Hilonga, Askwar; Kim, Hee Taik
The experimental results of aging time and temperature on the textural properties of water-glass (sodium silicate)-based silica aerogels are reported and discussed. Aging of the hydrogel for different times and temperatures led to an ability to increase the stiffness and strength of the networks. These improvements enabled the gel to withstand ambient pressure drying (APD) and, consequently, preserve the highly porous silica network without collapse. The pore size and volume increased with increasing aging temperature and time, while the specific surface area decreased. Monolithic aerogels with extremely low bulk density (~0.069 g/cm3), high specific surface area (820 m2g−1), large cumulative pore volume (3.8 cm3g−1), and high porosity (~96%) were obtained by aging at 60 oC for 18 hours. Therefore, easy synthesis of monolithic silica aerogels at ambient pressure is achievable using a relatively inexpensive silica precursor (sodium silicate).
Leguminous cover crops differentially affect maize yields in three contrasting soil types of Kakamega, Western Kenya
(Journal of Agriculture and Rural Development in the Tropics and Subtropics (JARTS), 2011) Ngome, Ajebesone; Becker, Mathias; Mtei, Kelvin
Maize production in smallholder farming systems in Kenya is largely limited by low soil fertility. As mineral fertilizer is expensive, green manuring using leguminous cover crops could be an alternative strategy for farmers to enhance farm productivity. However due to variability in soil type and crop management, the effects of green manure are likely to differ with farms. The objectives of this study were to evaluate Mucuna pruriens and Arachis pintoi on (i) biomass and nitrogen fixation (15 N natural abundance),(ii) soil carbon and nitrogen stocks and (iii) their effects on maize yields over two cropping seasons in Kakamega, Western Kenya. Mucuna at 6 weeks accumulated 1–1.3 Mg ha^{-1} of dry matter and 33–56 kg ha^{-1} nitrogen of which 70% was nitrogen derived from the atmosphere (Ndfa). Arachis after 12 months accumulated 2–2.7 Mg ha^{-1} of dry matter and 51–74 kg N ha^{-1} of which 52-63% was from Ndfa. Soil carbon and nitrogen stocks at 0–15 cm depth were enhanced by 2-4 Mg C ha^{-1} and 0.3–1.0 Mg N ha^{-1} under Mucuna and Arachis fallow, irrespective of soil type. Maize yield increased by 0.5-2 Mg ha^{-1} in Mucuna and 0.5–3 Mg ha^{-1} in Arachis and the response was stronger on Nitisol than on Acrisol or Ferralsol. We concluded that leguminous cover crops seem promising in enhancing soil fertility and maize yields in Kenya, provided soil conditions and rainfall are suitable
Experimental Investigations of Oxidation Stability of Biodiesel Produced from Manketti Seeds Oil (Schinziophyton rautanenii)
(ACS Publications, 2011-04-12) Kivevele, Thomas; Mbarawa, Makame M.
In this study, biodiesel from Manketti seeds oil (Schinziophyton rautanenii) was investigated to determine its suitability for use as a petrodiesel substitute. The fuel-related properties of Manketti oil methyl ester (MOME) were determined and compared to global biodiesel standards. Most of the determined fuel properties of MOME fulfilled the minimum requirements of ASTM D6751 and EN 14214 biodiesel standards. However, MOME did not meet EN 14214 oxidation stability requirements (6 h). The stability of biodiesel is very critical, and biodiesel requires antioxidants to meet storage requirements and to ensure fuel quality at all points along the distribution chain. This study evaluated the effectiveness of three antioxidants: 1,2,3-trihydroxybenzene (pyrogallol, PY), 3,4,5-trihydroxybenzoic acid (propyl gallate, PG), and 2-tert-butyl-4-methoxyphenol (butylated hydroxyanisole, BHA) on the oxidation stability of MOME. The result showed that the effectiveness of these antioxidants was in the order of PY > PG > BHA. Overall, the biodiesel derived from Manketti seeds oil can be used as partial substitute for mineral diesel.
Understanding the Emergence and Functioning of River Committees in a Catchment of the Pangani Basin, Tanzania
(Water Alternatives, 2011-06) Komakech, Hans; van der Zaag, Pieter
In this paper we explore the emergence and functioning of river committees (RCs) in Tanzania, which are local water management structures that allocate and solve water conflict between different water users (smallholder irrigators, large commercial farmers, municipalities, etc) along one river. The paper is based on empirical research of three committees in the Themi sub-catchment. The committees mostly emerged in response to drought-induced competition and conflict over water, rapid urbanisation around Arusha town, and the presence of markets for agricultural produce. The RCs are mainly active during dry seasons when water is scarce. We find that the emergence of the RCs can be understood by using the concept of institutional bricolage. We then assess their effective functioning with the help of the eight design principles proposed by Ostrom and find that the best performing RC largely complied with five of them, which indicates that not all principles are necessary for a water institution to be effective and to endure over time. The other two studied RCs complied with only three of these principles. All RCs leave the resource boundary open to negotiation, which lowers the transaction cost of controlling the boundaries and also allows future demands to be met in the face of increasing resource variability. All RCs do not fully comply with the principle that all affected must take part in rule creation and modification. In all three cases, finally, the 'nesting' of lower-level institutional arrangements within higher-level ones is inconsistent. To explain the difference in the performance of the three RCs we need to consider factors related to heterogeneity. We find that the functioning of RCs is strongly influenced by group size, spatial distance, heterogeneity of users and uses, and market forces.
Impact of antioxidant additives on the oxidation stability of biodiesel produced from Croton Megalocarpus oil
(Elsevier Ltd., 2011-06) Kivevele, Thomas; Mbarawa, Makame M.; Bereczky, Ákos; Laza, Tamás; Madarász, J.
The increase in crude petroleum prices, limited resources of fossil fuels and environmental concerns have led to the search of alternative fuels, which promise a harmonious correlation with sustainable development, energy conservation, efficiency and environmental preservation. Biodiesel is well positioned to replace petroleum-based diesel. Biodiesel is a non-toxic, biodegradable and renewable biofuel. But the outstanding technical problem with biodiesel is that, it is more susceptible to oxidation owing to its exposure to oxygen present in the air and high temperature. This happens mainly due to the presence of varying numbers of double bonds in the free fatty acid molecules. This study evaluates oxidation stability of biodiesel produced from Croton megalocarpus oil. Thermal and Oxidation stability of Croton Oil Methyl Ester (COME) were determined by Rancimat and Thermogravimetry Analysis methods respectively. It was found that oxidation stability of COME did not meet the specifications of EN 14214 (6 h). This study also investigated the effectiveness of three antioxidants: 1,2,3 tri-hydroxy benzene (Pyrogallol, PY), 3,4,5-tri hydroxy benzoic acid (Propyl Gallate, PG) and 2-tert butyl-4-methoxy phenol (Butylated Hydroxyanisole, BHA) on oxidation stability of COME. The result showed that the effectiveness of these antioxidants was in the order of PY > PG > BHA.
Electrocatalytic reduction of CO2 gas at Sn based gas diffusion electrode
(Elsevier B.V., 2011-07-01) Machunda, Revocatus; Ju, HyungKuK; Lee, Jaeyoung
The tin (Sn) based gas diffusion electrode was fabricated and applied for CO2 electroreduction in a zero gap cell. The fabrication was done by electrodeposition from a simple citrateechloride plating solution by chronoamperometric method. The electrode showed good stability during CO2 reduction even though the conversion of CO2 into formate reached only 18% faradaic efficiency during the initial 5 min and maintained about 12% until the end of the reduction time of 1 h.
Engine performance, exhaust emissions and combustion characteristics of a CI engine fuelled with croton megalocarpus methyl ester with antioxidant
(Elsevier Ltd., 2011-08) Kivevele, Thomas; Kristóf, Lukács; Bereczky, Ákos; Mbarawa, Makame M.
The use of biodiesel as a substitute for petroleum-based diesel has become of great interest for the reasons of combating the destruction of the environment, the price of petroleum-based diesel and dependency on foreign energy sources. But for practical feasibility of biodiesel, antioxidants are added to increase the oxidation stability during long term storage. It is quite possible that these additives may affect the clean burning characteristics of biodiesel. This study investigated the experimental effects of antioxidants on the oxidation stability, engine performance, exhaust emissions and combustion characteristics of a four cylinder turbocharged direct injection (TDI) diesel engine fuelled with biodiesel from croton megalocarpus oil. The three synthetic antioxidants evaluated its effectiveness on oxidation stability of croton oil methyl ester (COME) were 1, 2, 3 tri-hydroxy benzene (Pyrogallol, PY), 3, 4, 5-tri hydroxy benzoic acid (Propyl Gallate, PG) and 2-tert butyl-4-methoxy phenol (Butylated Hydroxyanisole, BHA). The fuel sample tested in TDI diesel engine include pure croton biodiesel (B100), croton biodiesel dosed with 1000 ppm of an effective antioxidant (B100 + PY1000), B20 (20% croton biodiesel and 80% mineral diesel) and diesel fuel which was used as base fuel. The result showed that the effectiveness of the antioxidants was in the order of PY > PG > BHA. The brake specific fuel consumption (BSFC) of biodiesel fuel with antioxidants decreased more than that of biodiesel fuel without antioxidants, but both were higher than that of diesel. Antioxidants had few effects on the exhaust emissions of a diesel engine running on biodiesel. Combustion characteristics in diesel engine were not influenced by the addition of antioxidants in biodiesel fuel. This study recommends PY and PG to be used for safeguarding biodiesel fuel from the effects of autoxidation during storage. Overall, the biodiesel derived from croton megalocarpus oil can be utilized as partial substitute for mineral diesel.
Water allocation and management in an emerging spate irrigation system in Makanya catchment, Tanzania
(Elsevier, 2011-09) Komakech, Hans; Mul, Marloes; van der Zaag, Pieter; Rwehumbiza, Filbert
Although spate irrigation systems are risk-prone, they can be an important component for livelihood security in semi-arid areas. Spate uses water (flood water), which upstream users often do not require, as rainfall during these periods is more than sufficient. The use of this flood water for spate irrigation is therefore a good opportunity to convert water with a low opportunity cost to high value water. As more rivers are closing, due to socio-economic and climate changes, spate irrigation may become increasingly relevant in semi-arid areas. Spate irrigation systems pose institutional and technical challenges: collective action is challenged by complex upstream–downstream interactions between users within the system, and the high labour demands for regular reconstruction of temporary diversion weirs and intake structures. This paper describes a spate irrigation system in Makanya village, Tanzania that emerged in response to increased upstream water use. We use three of the four dimensions (hydrological, hydraulic and sociological) of spate irrigation proposed by Van Steenbergen (1997) to assess the Makanya spate irrigation system. The Makanya spate irrigation system has an organisational structure that is similar to the canal irrigation (furrow) committees located upstream, and effectively deals with the institutional demands of managing water in spate irrigation systems. Water allocation is reminiscent to the water sharing arrangements existing in the full irrigation system, which previously was in place at the site and in the high- and midlands of the Makanya catchment and therefore set this system apart from the traditional spate irrigation practice elsewhere. Technically, a major challenge is the reconstruction of the head works after each flood. Another aspect is the changes in the river bed. Flash floods carry sediments that deposit on the fields, raising the elevation of the irrigated land every year and making it increasingly difficult for the river water to enter the plots. Improving system efficiency through modernisation of the diversion and distribution structures in this case is not feasible due to the huge amounts of sediments delivered to the system each year. Instead investments in conjunctive use of groundwater could be the solution because it involves a relatively small intervention, minimises the physical disturbance of the system, and therefore is likely to respect the existing locally developed water management arrangements.
Pangani River Basin over time and space: On the interface of local and basin level responses
(Elsevier, 2011-09) Komakech, Hans; van Koppen, Barbara; Mahoo, Henry; van der Zaag, Pieter
As the pressure on the water resources mounts within a river basin, institutional innovation may occur not as a result of a planned sequence of adjustments, but arising out of the interplay of several factors. By focusing on the basin trajectory this paper illustrates the importance of understanding how local-level institutional arrangements interface with national-level policies and basin-wide institutions. We expand Molle's typology of basin actors responses by explicitly introducing a meso-layer which depicts the interface where State-level and local-level initiatives and responses are played out; and focus on how this interaction finds expression in the creation and modification of hydraulic property rights. We subsequently apply this perspective to the case of Pangani River Basin in Tanzania. The Pangani River Basin development trajectory did not follow a linear path and sequence of responses. Attempts by the state government to establish ‘order’ in the basin by issuing water rights, levying water fees and designing a new basin institutional set-up have so far proven problematic, and instead generated ‘noise’ at the interface. So far water resources development in the Pangani has primarily focused on blue water, and the paper shows how investments in infrastructure to control blue water have shaped the relationship between water users, and between water user groups and the State. It remains unknown, however, what the implications will be of widespread investments in improved green water use throughout the basin – not only hydrologically for the availability of blue water, but also socially for the livelihoods of the basin population, and for the evolving relationships between green and blue water users, and between them and the State. The paper concludes with a question: will green water development engender a similar double-edged material-symbolic dynamic as blue water development has. The findings of this paper demonstrate that the expanded typology of basin actors’ responses helps to better understand the present situation. Such an improved understanding is useful in analysing current and proposed interventions.
Theoretical Study of Structure, Vibration Spectra and Thermodynamic Properties of Cluster Ions in Vapors over Potassium, Rubidium and Cesium Chlorides
(Springer Nature Switzerland AG., 2011-10-04) Pogrebnaya, Tatiana P.; Hishamunda, Jean B.; Girabawe, Camille; Pogrebnoi, Alexander M.
The geometrical structure, the frequencies of normal vibrations, and the thermodynamic characteristics of tri- and pentaatomic cluster ions M2Cl+, MCl 2 − , M3Cl 2 + , and M2Cl 3 − (M = K, Rb, or Cs) existing in saturated vapors over potassium, rubidium, and cesium chlorides have been calculated by nonempirical methods. According to the calculations, the triatomic ions have a linear equilibrium configuration of D ∞h symmetry. For the pentaatomic ions M3Cl 2 + and M2Cl 3 − , three isomeric forms were considered. The most abundant isomer in saturated vapor was found to be the linear one (D ∞h) for K3Cl 2 + , Rb3Cl 2 + , K2Cl 3 − , Rb2Cl 3 − and Cs2Cl 3 − , and the angular V-shaped (C 2v) for Cs3Cl 2 + . The concentration of the other two isomers, cyclic and bipyramidal, is negligible. The energies and enthalpies of dissociation of the ions have been found. The enthalpies of formation of the ions, Δf H°(0 K) in kJ/mol, were obtained: 116 ± 3 (K2Cl+), −623 ± 3 (KCl 2 − ), −228 ± 7 (K3Cl 2 + ), −971 ± 6 (K2Cl 3 − ), 91 ± 3 (Rb2Cl+), −620 ± 3 (RbCl 2 − ), −256 ± 5 (Rb3Cl 2 + ), −967 ± 4 (Rb2Cl 3 − ), 51 ± 4 (Cs2Cl+), −622 ± 3 (CsCl 2 − ), −301 ± 8 (Cs3Cl 2 + ), −975 ± 6 (Cs2Cl 3 − ).
Evaluation of the Oxidation Stability of Biodiesel Produced from Moringa oleifera Oil
(ACS Publications, 2011-10-19) Kivevele, Thomas; Mbarawa, Makame M.; Bereczky, Ákos; Zöldy, Máté
Biodiesel is considered as an alternative fuel to petroleum-based conventional diesel fuel. Dependent upon the raw material, biodiesel can contain more or less unsaturated fatty acids in its composition, which are susceptible to oxidation reactions accelerated by exposure to oxygen and high temperatures. The present study evaluated the oxidative stability of biodiesel produced by methanolysis of Moringa oleifera oil, primarily available on the African continent. The evaluation was conducted by means of the Rancimat instrument, at a temperature of 110 °C, with an air flow of 10 L/h. Moringa oil methyl ester (MOME) displayed an oxidation stability of 5.05 h. Thus, MOME met the oxidative stability requirement in the American Society for Testing and Materials (ASTM) D6751 standard, which prescribes a minimum of 3 h, but did not meet the minimum requirement prescribed in the EN 14214 standard, which is 6 h. Also, this study evaluated the effectiveness of four antioxidants, 1,2,3-trihydroxybenzene [pyrogallol (PY)], 3,4,5-trihydroxybenzoic acid [propyl gallate (PG)], 2-tert-butyl-4-methoxyphenol [butylated hydroxyanisole (BHA)], and 2,6-di-tert-butyl-4-methylphenol [butylated hydroxytoluene (BHT)], on the oxidation stability of MOME. The result showed that the effectiveness of these antioxidants was in the order of PY > PG > BHA > BHT.
Integrated Process for Sustainable Agro-process Waste Treatment and Climate Change Mitigation in Eastern Africa
(International Livestock Research Institute (ILRI), 2011-11) Njau, Karoli; Kyambadde, Joseph; Dawit, Mekibib David; Hermogène, Nsengimana
Eastern Africa countries are faced with similar development challenges including high population growth rate, low agricultural productivity, increasing number of agro-processing industries, pollution and contamination of water sources by agro-processing industrial wastes, inadequate energy supplies and climate change effects such as extreme drought and flooding. It is therefore imperative to address these challenges in an integrated and regional manner, in which key stakeholders including the public and private sectors are actively engaged. The goal of this Consortium is to contribute to climate change mitigation, environmental sustainability, and agricultural development by applying strategic waste management innovation systems in Eastern Africa (focussing on Ethiopia, Tanzania and Uganda). Specifically the project aims to: (1) Strengthen capacity to sustainably manage agro-process wastewater in Eastern Africa; (2) Develop and optimize innovative wastewater treatment processes integrating biogas production and water/nutrient reuse for enhanced industrial and agricultural productivity in Eastern Africa and; (3) Evaluate and disseminate the economic, environmental and social benefits of the integrated wastewater treatment bioprocesses. We will achieve our objectives by use of appropriate technologies that will be designed, developed and optimized to achieve: (1) better treatment of agro-process wastewaters (slaughterhouse, tannery and Banana wine processing wastewaters) in Uganda, Ethiopia and Tanzania, respectively and; (2) generation of useable by-products such as biogas, bio-fertilizers, and agricultural products (vegetables, flowers, animal feed/pasture grass) from wastewater treatment processes. Through this integrated wastewater treatment approach, we will contribute to environmental, social and economic development of Eastern African countries including reduction in pollution and contamination of water sources receiving agro-processing wastewaters, reduction in incidences of water related diseases such as diarrhoea, reductions in emission of greenhouse gases (GHG); generation of renewable energy source (biogas), slow down the rate of deforestation for firewood and charcoal, reduce indoor air pollution (IAP) and respiratory diseases since Biogas burns smoke free, and improve agricultural productivity by provision bio-fertilizers. The proposed Consortium hinges on lessons learned from the successes and challenges of previous SIDA/SAREC projects in Eastern Africa, especially BIO-EARN programme phase 3 which carried out treatment of slaughterhouse wastewater at City Abattoir (Uganda) and tannery wastewater at Modjo Tannery (Ethiopia). Whereas the project treated these industrial wastewaters, they were not economically sustainable because they did not addvalue to wastes by integrating hydroponic systems for vegetables and flowers cultivation, production of useable byproducts such as biogas and bio-fertilizers into the treatment process to make it sustainable. The proposed Environmental Innovation Project Consortium II comprises of scientists from Waste Stabilization Ponds (WSP) & Constructed Wetland Research and Development group (University of Dar Es Salaam - UDSM), Department of Biochemistry (Makerere University - MAK), School of Graduate Studies University of Addis Ababa (Ethiopia - AAU), National University of Rwanda (NUR), and AKUT Burkard and Partner (Germany, www.akut-umwelt.de, AKUT). The private sector partners involved in this consortium include Bassajabalaba Hides and Skins - City Abattoir (Uganda), Modjo Tannery, Addis Ababa (Ethiopia), and Banana Investments Ltd, Arusha, (Tanzania). Each scientific partner contributes technical skills, experiences and synergies to the Consortium: UDSM has engineers with technical experiences in constructed wetland technologies; AKUT Partner has experience in designing and installation of industrial scale biogas digester plants; MAK and AAU have experiences in operation of reactors and constructed wetlands treating slaughterhouse and tannery wastewaters, respectively. On the other hand, Bassajabalaba Hides and Skins, City Abattoir (Uganda) and Modjo, Tannery (Ethiopia) both have over four years (2006-2010) experience in operation of integrated technologies treating high strength slaughterhouse and tannery wastewaters, respectively, under the SIDA/SAREC supported BIO-EARN project. Whereas Banana Investments Ltd, Arusha (Tanzania) have not participated in similar arrangements, they have committed strong technical, financial and in kind support towards the success of the proposed Consortium project. The proposed Consortium project is anticipated to run on budget of USD 1,199,684 over a period of three years (2011 -2013).

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