49 research outputs found

    Experimental Investigations of Oxidation Stability of Biodiesel Produced from Manketti Seeds Oil (Schinziophyton rautanenii)

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    This research article published by ACS Publications, 2011In 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

    Synthesis and characterization of polyesters from renewable cardol

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    The preparation and thermal characteristics of new polyesters from cardol, a renewable monomer obtained as a by-product of the cashew industry, are reported. Cardol - a diol component of the natural product cashew nut shell liquid (CNSL) was isolated and reacted with adipoyl chloride and terephthaloyl chloride in a 1:1 molar ratio in hexane and toluene as solvents at 170 °C under nitrogen atmosphere. The cardol based polyesters [poly(cardyl adipate) and poly(cardyl terephthalate)] were produced in good yields of up to 63 and 54%, respectively. The polymers were analysed by FT-IR for functional groups elucidation and by combined thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) for thermal stability. The cardol-based polyesters were thermally stable up to about 400 °C. The thermal stability of poly(cardyl terephthalate) was higher than that of poly(cardyl adipate) under similar conditions. All prepared polyesters were insoluble in common laboratory solvents at room temperature

    Engine performance, exhaust emissions and combustion characteristics of a CI engine fuelled with croton megalocarpus methyl ester with antioxidant

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    This research article published by Elsevier Ltd., 2011The 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

    Evaluation of the Oxidation Stability of Biodiesel Produced from Moringa oleifera Oil

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    This research article published by ACS Publications, 2011Biodiesel 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

    FOSS4G 2018

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    The GEO-ICT is an institutional cooperation project aiming at improving the quality and societal relevance of geospatial and ICT research and education at the Universities of Dar es Salaam (UDSM), Ardhi University (ARU), State University of Zanzibar (SUZA) and Sokoine University of Agriculture (SUA). Jointly with the University of Turku (UTU) Finland, the institutions focus on strengthening geospatial and ICT skills of the staff, establishing new curricula, upgrading supportive infrastructures and creating synergetic cooperation modalities with different stakeholders in the society. In this paper we share how our practical experiences of the cooperation, including what is the background for the establishment of institutional cooperation between these universities, how is the project operating in practice, what type of activities and cooperation modalities we do together and how do we think institutional cooperation contributes to the advancement of geospatial expertise in Tanzania and what is the role of open source solutions in this development.</p

    Impact of antioxidant additives on the oxidation stability of biodiesel produced from Croton Megalocarpus oil

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    This research article published by Elsevier Ltd., 2011The 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

    BUILDING GEOSPATIAL COMPETENCES IN TANZANIAN UNIVERSITIES WITH OPEN SOURCE SOLUTIONS

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    The GEO-ICT is an institutional cooperation project aiming at improving the quality and societal relevance of geospatial and ICT research and education at the Universities of Dar es Salaam (UDSM), Ardhi University (ARU), State University of Zanzibar (SUZA) and Sokoine University of Agriculture (SUA). Jointly with the University of Turku (UTU) Finland, the institutions focus on strengthening geospatial and ICT skills of the staff, establishing new curricula, upgrading supportive infrastructures and creating synergetic cooperation modalities with different stakeholders in the society. In this paper we share how our practical experiences of the cooperation, including what is the background for the establishment of institutional cooperation between these universities, how is the project operating in practice, what type of activities and cooperation modalities we do together and how do we think institutional cooperation contributes to the advancement of geospatial expertise in Tanzania and what is the role of open source solutions in this development

    Childhood adversity, mental ill-health and aggressive behavior in an African orphanage: Changes in response to trauma-focused therapy and the implementation of a new instructional system

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    <p>Abstract</p> <p>Background</p> <p>The number of orphans in Sub-Saharan Africa is constantly rising. While it is known that family or community care is preferable over institutional care of African orphans, little is known about the quality of care in orphanages and possibilities of improvement.</p> <p>Study 1</p> <p>Methods</p> <p>Exposure to traumatic stress, experiences of violence in the home, school and orphanage, as well as mental ill-health and aggression of 38 children (mean age of <it>M </it>= 8.64 years) living in an orphanage in rural Tanzania were assessed at two time points. The severity of post-traumatic stress disorder symptoms (PTSD), depressive symptoms, and internalizing and externalizing problems were used as indicators of mental ill-health.</p> <p>Results</p> <p>Violence experienced in the orphanage correlated more strongly with all indicators of mental ill-health than violence in the former home, school or neighborhood at time point 1. Additionally, violence experienced in the orphanage had a positive relationship with the aggressive behavior of the children at time point 2.</p> <p>Study 2</p> <p>Methods</p> <p>With the help of the pre-post assessment of Study 1, the implementation of a new instructional system and psychotherapeutic treatment (KIDNET) for trauma-related illness were evaluated.</p> <p>Results</p> <p>In response to both, a change in the instructional system and psychotherapeutic treatment of PTSD, a massive decline in experienced violence and in the severity of PTSD-symptoms was found, whereas depressive symptoms and internalizing and externalizing problems exhibited little change.</p> <p>Conclusions</p> <p>These studies show that violence, especially in the orphanage, can severely contribute to mental ill-health in orphans and that mental health can be improved by implementing a new instructional system and psychotherapeutic treatment in an orphanage. Moreover, the results indicate that the experience of violence in an orphanage also plays a crucial role in aggressive behavior of the orphans.</p

    Assessment of the Anthelmintic Efficacy of Albendazole in School Children in Seven Countries Where Soil-Transmitted Helminths Are Endemic

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    Soil-transmitted helminths (roundworms, whipworms and hookworms) infect millions of children in (sub)tropical countries, resulting in malnutrition, growth stunting, intellectual retardation and cognitive deficits. Currently, there is a need to closely monitor anthelmintic drug efficacy and to develop standard operating procedures, as highlighted in a World Health Organization–World Bank meeting on “Monitoring of Drug Efficacy in Large Scale Treatment Programs for Human Helminthiasis” in Washington DC at the end of 2007. Therefore, we have evaluated the efficacy of a commonly used treatment against these parasitic infections in school children in Africa, Asia and South-America using a standardized protocol. In addition, different statistical approaches to analyzing the data were evaluated in order to develop standardized procedures for data analysis. The results demonstrate that the applied treatment was highly efficacious against round- and hookworms, but not against whipworms. However, there was large variation in efficacy across the different trials which warrants further attention. This study also provides new insights into the statistical analysis of efficacy data, which should be considered in future monitoring and evaluation studies of large scale anthelmintic treatment programs. Finally, our findings emphasize the need to update the World Health Organization recommended efficacy threshold for the treatment of STH

    The orphaning experience: descriptions from Ugandan youth who have lost parents to HIV/AIDS

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    The HIV/AIDS epidemic has continued to pose significant challenges to countries in Sub-Saharan Africa. Millions of African children and youth have lost parents to HIV/AIDS leaving a generation of orphans to be cared for within extended family systems and communities. The experiences of youth who have lost parents to the HIV/AIDS epidemic provide an important ingress into this complex, evolving, multi-dimensional phenomenon. A fundamental qualitative descriptive study was conducted to develop a culturally relevant and comprehensive description of the experiences of orphanhood from the perspectives of Ugandan youth. A purposeful sample of 13 youth who had lost one or both parents to HIV/AIDS and who were affiliated with a non-governmental organization providing support to orphans were interviewed. Youth orphaned by HIV/AIDS described the experience of orphanhood beginning with parental illness, not death. Several losses were associated with the death of a parent including lost social capitol, educational opportunities and monetary assets. Unique findings revealed that youth experienced culturally specific stigma and conflict which was distinctly related to their HIV/AIDS orphan status. Exploitation within extended cultural family systems was also reported. Results from this study suggest that there is a pressing need to identify and provide culturally appropriate services for these Ugandan youth prior to and after the loss of a parent(s)
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