The determination of crop coefficient (Kc) with adequate methodology is important to quantify regional water requirement. Jatropha (Jatropha curcas L.) Kc is still unknown and this information will be essential to provide reliable irrigation parameters, as well as for crop zoning. The objective of this study was to determine jatropha actual crop evapotranspiration (ETc) and Kc from 1st to 4th growing year, and correlate Kc with leaf area index (LAI) and cumulative thermal unit (CTU). The experiment was performed from March 2012 to August 2015 at \"Luiz de Queiroz\" College of Agriculture (ESALQ)/University of São Paulo (USP), at Piracicaba city, SP, Brazil. The experiment was divided into center pivot, drip, and rainfed treatments. Two large weighing lysimeters (12 m2 each lysimeter) per treatment were used to determine jatropha ETc (one plant per lysimeter). Reference evapotranspiration (ET0) was determined by Penman-Monteith method from a weather station data situated close to the treatments. Daily Kc was determined for the two irrigated treatments by the ration between ETc and ET0 (Kc=ETc/ET0). LAI was determined using the LAI-2200 plant canopy analyzer, which was previously calibrated for jatropha canopy type. In all growing years, LAI was almost zero at the beginning of vegetative stage, increasing until a maximum during productive stage, and decreasing to zero in the leaf senescence stage. Annual ETc trend during the three growing was very similar, which was explained by the different growing periods and the LAI variation. In the 1st year Kc was 0.47 for both treatments. In the 2nd, 3rd, and 4th years Kc ranged from 0.15 to 1.38 for center pivot treatment and from 0.15 to 1.25 for drip treatment. Kc average in 2nd, 3rd, and 4th years during vegetative and productive growing periods was 0.77, 0.93, and 0.82 for center pivot treatment, respectively, and 0.69, 0.79, and 0.74 for drip treatment, respectively. The relationship between Kc and LAI for the center pivot treatment was adjusted to a logarithmical equation with coefficient of determination (R2) and root mean square error (RMSE) of 0.7643 and 0.334, respectively. For the drip treatment R2 was 0.8443 and 0.2079, respectively. In all three years analyzed, Kc related to CTU by a 3rd degree polynomial equation for both treatments. / A determinação de coeficiente de cultivo (Kc) com metodologia adequada é essencial para quantificar o consumo hídrico de cultivos em diferentes regiões. Valores de Kc do pinhão-manso (Jatropha curcas L.) ainda não foram determinados e essa informação é muito importante para auxiliar o manejo de irrigação de maneira adequada. O objetivo desse estudo foi determinar a evapotranspiração (ETc) e Kc do 1º ao 4º ano de cultivo do pinhão-manso, e correlacionar Kc com o índice de área foliar (IAF) e a soma da unidade térmica (SUT). O experimento foi realizado de março de 2012 à agosto de 2015 na Escola Superior de Agricultura \"Luiz de Queiroz\" (ESALQ)/Universidade de São Paulo (USP), na cidade de Piracicaba, SP, Brasil. O experimento foi divido nos tratamentos irrigados por pivô central, gotejamento e sem irrigação. Foram utilizados dois lisímetros de pesagem (12 m2 de superfície em cada lisímetro) por tratamento para realizar a determinação de ETc (uma planta por lisímetros). A evapotranspiração de referência (ET0) foi determinado pelo método de Penman-Monteith a partir de dados meteorológicos coletados na estação meteorológica localizada ao lado do experimento. Valores diários de Kc foram determinados nos tratamentos irrigados pela razão entre ETc e ET0 (Kc=ETc/ET0). IAF foi determinado utilizando o equipamento LAI-2200 Plant Canopy Analyzer, que foi previamente calibrado para adequar as características do dossel do pinhão-manso. Em todos os anos avaliados, o IAF foi quase zero durante o início do período vegetativo, aumentando os valores conforme a planta começou a se desenvolver até atingir valores máximos durante o período produtivo, decrescendo os valores até zero no estádio de desenvolvimento de senescência foliar. A variação anual de ETc no 2º, 3º e 4º ano foi muito similar, explicado pelos diferentes períodos de desenvolvimento da cultura e a variação de IAF no ano. No 1º ano, Kc foi 0,47 para os dois tratamentos irrigados. No 2º, 3º e 4º ano, Kc variou de 0,15 a 1,38 no tratamento irrigado por pivô central e de 0,15 a 1,15 no tratamento irrigado por gotejamento. A média dos valores de Kc no 2º, 3º e 4º ano durante os períodos vegetativos e produtivos foi de 0,77, 0,93 e 0,82 no tratamento irrigado por pivô central, respectivamente, e 0,69, 0,79 e 0,74 no tratamento irrigado por gotejamento, respectivamente. A relação entre Kc e IAF mostrou, para o tratamento irrigado por pivô central, um ajuste logaritmo com coeficiente de determinação (R2) e somatória do erro médio ao quadrado (SEMQ) de 0,7643 e 0,334, respectivamente, e 0,8443 e 0,2079 para o tratamento irrigado por gotejamento, respectivamente. Nos três anos analisados, Kc correlacionado com SUT mostrou o melhor ajuste à equação polinomial de 2ª ordem para os dois tratamentos.

The rapid expansion of biofuel projects in southern Africa creates an opportune issue against which to examine land-use tradeoffs within the areas of customary land tenure. For this an ecosystems services approach is used. Jatropha curcas (L), a perennial oilseed plant which has been the key focus of most of the region’s biofuel expansion to date is used as the focus biofuel crop for which case study data were obtained from Malawi, Mozambique, Zambia and South Africa. Despite the initial enthusiasm for jatropha, most projects have proven less successful than hoped, and many have collapsed. A few are, however, still showing signs of possible success and it is two of these that form the basis of the case studies. Hugely complex tradeoffs are involved when considering biofuel as a land-use option for communal areas. They range from global impacts such as biodiversity and global climate forcing, through national concerns of rural development, national food security and national fuel security, to local household concerns around improving livelihoods. Land that is converted to biofuel needs to be removed from some previous use, and in the southern African case it is typically woodlands and the multitude of services they provide, that suffer. The nature of the tradeoffs and the people affected change over the scale under consideration. For the local farmer it is only the local issues that are of concern, but national and global forces will change the policy environment and lead to new types of development such as biofuels. Change is inevitable, and in all developments there are likely to be both winners and losers. It is clear that the impacts arising from biofuel are situation dependent, and each community and location has unique social and environmental considerations that need to be taken into account. In the case of jatropha the final realised yield and the economic returns that this can generate, will be of critical importance and remain one of the main uncertainties. There are promising signs that under certain circumstances the balance of benefits from jatropha biofuel may be positive, but if implemented incorrectly or in the wrong place, there is extensive evidence of total project failure. It is clear that evidence-based data and assessment tools are needed to assist communities, developers and government departments to make sound decisions around biofuel (or other land-use based) development. A number of such tools are suggested in the thesis. Both the use of large-scale plantations or small-scale farmer centred projects have their advantages and disadvantages. It is probable that in the correct circumstances either can work. However, large-scale plantations can have huge negative social and environmental consequences if poorly implemented. Small-scale projects, though improving livelihoods, are unlikely to take the farmers out of poverty. Tradeoffs from any land-use change are inevitable. Empirical data on biofuel impacts on the environment and society are needed for the development of sound policy. A favourable policy environment can ensure that positive benefits from biofuel are obtained, whilst minimising negative impacts. To develop this policy means that southern African countries will have to clearly understand what they wish to achieve from biofuel, as well as having a clear understanding of impacts from biofuel implementation. Sound scientific knowledge needs to underpin this process. For instance governments may wish to increase the ratio of small-scale to large-scale plantation to increase the developmental benefits, ensure biofuel is used to promote national fuel security rather than being exported, or develop a medium-scale farming sector which can help move farmers out of poverty and assist in developing a market surplus of agricultural commodities. Analysing impacts from biofuel expansion is a complex and multi-dimensional problem and as such will require multi-criteria analysis tools to develop solutions. Global, national and local tradeoffs must all be considered. In addition a wide range of stakeholders are involved and participatory processes may be needed to capture their inputs. Tools to better analyse impacts, specifically at the local level are needed. These local results need to feed into national level economic assessments. The cost of biofuel introduction should be considered against the costs of not implementing biofuel, realising that doing nothing also has a cost and long-term impact. Third-party certification provides a useful tool for shifting costs of ensuring compliance with social and environmental legislation, from the state to biofuel companies. In addition ongoing monitoring and evaluation of existing projects is needed to learn from successes and failures, to identify unintended consequences, and to increase the resilience of projects, community livelihoods and the national economy. This will have to be supplemented with additional focused and ongoing research.

Biofuels now days consider as one of the successful alternative to meet the challenges associated with climate change and peak oil, as well as a way for poorer countries to develop an industry in order to enhance social and economic development. In many developing countries and particularly in Africa, this has led to large-scale investments in lands by foreign companies, and as a consequence there has been a debate on whether these actions are environmentally sustainable and whether this kind of activity actually brings economic development. The investments of biofuels in Africa, espe-cially the Jatropha plantations are debatable. Several arguments have been concentrat-ed on development goals, economic issues and environmental concerns. This report evaluates the status of some Jatropha projects in Sudan, Ethiopia, Kenya and Tanza-nia, the outcomes of the report show that biofuels from Jatropha lead to a significant socio -economic benefits by creating many jobs opportunities and improve the stand-ard of living in Africa. However, inadequate funding’s, high investment costs, no clear policies for biodiesel are the most challenging for Jatropha in Africa which need fur-ther mechanisms and ideology by African scientists, leaders, NGOs, farmers and deci-sion makers. In the studied countries, it was reported that the Jatropha produce low yields of oil seeds especially in the marginal lands with no enough water supplies. In Kenya the productivity of Jatropha is very low for large scale- project. Moreover some social and environmental impacts are also seen for Jatropha cultivations in Ethiopia, Kenya and Tanzania. Some Jatropha projects have impacted the food security nega-tively; nevertheless some biofuels experts believe that Jatropha has no any adverse im-pacts on food security since it is inedible and grown on marginal lands. In Ethiopia, the main environmental impacts of Jatropha are related to biodiversity, water quality and quantity. In Kenya, the environmental impacts are related to biodiversity, carbon emissions, water withdrawal, pollution of agro- chemicals usage, deforestation and soil erosion, whereas in Tanzania, the main environmental issues are connected to the change of land use system, impacts on biodiversity and impacts on water resources.

Thesis (M. Sc. (Horticulture)) -- University of Limpopo, 2020 / Tea is globally regarded as the second most consumed in the world after water. It is associated with various health benefits such as anti-cancer, anti-inflammation, anti-obesity and reduction in cholesterol blood levels. Jatropha zeyheri indigenous tea has medicinal and nutritional properties, therefore knowledge of its chemical compositions is essential for increasing its quality. This indigenous tea is currently harvested in rural areas when the leaves are already dry, which is in contrary to what is practised in most tea industries. Therefore, the determination of harvesting time has an opportunity to contribute towards increasing the quality of J. zeyheri indigenous tea. The study investigated whether harvesting times has an effect on essential and non-essential mineral elements and phytochemicals and antioxidant activity of J. zeyheri leaves. The study materials were collected in the wild at Khureng village, Lepelle-Nkumpi Municipality, Limpopo Province, South Africa. Five treatments constituting of harvesting times (February, March, April, May and June) were arranged in a randomised complete block design, with 10 replications. Leaves were harvested, oven-dried at 60°C for 24 hrs and pulverised. A microwave digestion system (PerkinElmer, Titan MPS, United States) was used to prepare the samples prior analysis. After the preparations, mineral elements were determined using Inductively Coupled Plasma Emission Spectrometer-9000 (Shimadzu, Japan). The 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity assay was used to quantify the antioxidant activity of the acetone extracts of plants. The total phenol and tannin contents in each plant extract were determined using the Folin-Ciocalteu assay method. The total flavonoid contents were determined using the Aluminium Chloride colorimetric assay. The absorbance for antioxidant activity and phytochemicals were recorded using UV/visible spectrophotometer (Beckman Coulter-DU730, USA). Harvesting times had highly significant effects on Cr, Fe, K, Mg, Ni, P and S contributing 58, 65, 73, 62, 55, 67 and 69%, respectively, in total treatment variation, but were significant on Ca, Cu, Mn, Al, Co and Na contributing 62, 58, 66, 53 and 57%, respectively, in total treatment variation (TTV). However, harvesting times did not influence Zn and Si amounts in J. zeyheri leaves. Harvesting times increased majority of essential and non-essential mineral elements, except for K which was gradually decreased. Essential and non-essential mineral elements over different harvesting times exhibited positive quadratic relations. Using the optimisation equation (x = –b1/2b2) from the quadratic equation, harvesting of J. zeyheri was optimised at 2.46 months. Harvesting times had highly significant effects on the antioxidant activity, total phenol and flavonoid contents contributing 62, 88 and 60% in total treatment variation, respectively, but was not significant on total tannin contents. The negative quadratic relationship models explained 51, 90 and 95% of the observed variation in antioxidant activity, total phenol and flavonoid contents, respectively. In conclusion, findings of this study suggested that harvesting of J. zeyheri leaves be done between April-May for improved accumulation of mineral elements, whereas, for phytochemicals and antioxidant activity the results suggested that further studies be conducted from early summer until winter to find the optimum harvesting time of J. zeyheri indigenous tea. / National Research Foundation (NRF)

Thesis (M.Sc. (Horticulture)) -- University of Limpopo, 2020 / Most rural communities harvest different plant parts of Jatropha zeyheri for nutritional and medicinal purposes. However, the decision of choosing to harvest the plant part with desired chemical components is essential for quality purposes. Nevertheless, there is a lack of information regarding the distribution of chemical composition in different plant parts of J. zeyheri tea. Therefore, the objectives of the study were to: (1) investigate the effect of different plant parts (stems, roots and leaves) of J. zeyheri on mineral composition and, (2) determine the effect of different plant parts (stems, roots and leaves) of J. zeyheri on phytochemicals and antioxidant activity. A study was conducted with three treatments, namely stems, roots and leaves arranged in a randomised complete block design (RCBD), with 10 replications. Plant materials were collected in the wild from mature plants between June-July 2018. Leaves and stems were manually separated, while roots were cut into smaller pieces, dried at 60°C for 48 hours in an air-forced oven and later finely ground using an electric grinder. Mineral elements were determined using Inductive Coupled Plasma Emission (ICPE-9000 Shimadzu, Japan). Phytochemical tests were performed to detect the presence of flavonoids, tannins, alkaloids and saponins, whereas 2,2-Diphenyl-1-picrylhydrazyl (DPPH) antioxidant qualitative test was performed using TLC plates. Antioxidant activity and phytochemicals constituents were quantified using UV/Visible spectrophotometer. Results of this study demonstrated that plant parts had a highly significant effect on essential mineral elements, copper (Cu), iron (Fe), potassium (K), magnesium (Mg), zinc (Zn), manganese (Mn), phosphorus (P) and nickel (Ni) contributing 82, 75, 97, 88, 86, 96, 79 and 82% to total treatment variation (TTV), respectively, whereas, calcium (Ca) had a significant effect contributing 69%, while no significant effect on sulphur (S) was observed. Among the tested essential mineral elements, Ca, Zn, Cu and Ni were consistently the highest in the leaf, followed by stem whereas, the root had the lowest contents. Manganese and Mg were consistently the highest in the stem, followed by leaf whereas, the root had the lowest content. Iron was highest in the leaf followed by root and was lowest in the stem. Also, the stem had the highest content of K whereas, the leaf and the root had moderately lower content, and P was high in the leaf, whereas, stem and root had lower content. Similarly, plant parts had a highly significant effect on non-essential mineral elements, aluminium (Al), sodium (Na), cobalt (Co) and chromium (Cr) contributing 85, 72, 84 and 81% in TTV, respectively, whereas, not significant on silicon (Si). Among the tested non-essential mineral elements, the leaf had the highest content of Al, Na, Cr, and Co followed by the stem, whereas, the root had the lowest. The screening of phytochemicals showed that flavonoids, tannins, alkaloids and saponins were present within different plant parts of J. zeyheri. The results from DPPH qualitative assay of J. zeyheri plant parts showed more yellow spots in leaf and root whereas, there was lesser amount in stem indicating that the plant exhibited antioxidant activity. Plant parts had highly significant effect on total flavonoids contributing 72% in TTV, however, had a significant effect on tannins and antioxidant activity contributing 56 and 79% in TTV, respectively. In contrast, plant parts were not significant on total phenols. The leaf had the lowest of total flavonoids content, whereas root and stem reported the higher contents and root had a lower content of tannins and antioxidant activity, whereas stem and leaf reported higher contents. In conclusion, the majority of chemical properties were recorded in leaves followed by stems and lastly in the roots. The result of this study suggested that J. zeyheri tea beverage can be brewed from leaves predominantly followed by stems or alternatively they can be combined. / National Research Foundation (NRF) and Limpopo Agro-Food Technology Station (LATS)

Jatropha constitutes one of promising species suitable for providing oil for biodiesel production. So, looking for good practice and sustainable use of energy during Jatropha cultivation and lack of information about Jatropha in Mozambique, this study pretends to estimate the energy balance in Jatropha plantation in Sun biofuel farm, by calculating the energy indicators based on a life cycle approach in Sun Biofuel farm located in Manica province, Central Mozambique. Energy balance is a tool which can help to calculate all energy indicators in order to evaluate and analyse the energy efficiency, sustainability and environmental benefits. This study estimated the indicator of energy balance namely: energy input is the sum of all energy used during the process of Jatropha cultivation and oil production, energy output is the amount of energy produced, Net energy value can be calculated subtracting the energy output from the energy input, Energy productivity is the division of Jatropha produced by the respective input energy, specific energy is the division of energy input by Jatropha seed output and energy ratio is the energy output divided by energy input. Also data was collected on the farm of Sun Biofuel to estimate the sustainability of agricultural production of the company. The Jatropha production in Sun Biofuel farm (SBF) absorbed around 28 579 MJ/ha of energy during the production and 121 820 MJ/ha of energy gain as result of the all production. The total energy input was direct energy with 77% and Indirect energy with 23% used in Jatropha farm, and also the total energy input was divided into renewable with 26% and non-renewable with 74% of its contribution. The results revealed that the contribution of seed husks was (8%), woody products (38%), raw seed oil (30%), Shell (9%) and press cake (15%) of total energy output in Jatropha oil production farm. Net energy value (NEV), energy productivity, energy use efficiency and Specific energy was 93 241 MJ ha-1, 0.067 Kg MJ-1, 4.3 and 15.04 MJ Kg-1, respectively. According to these results the energy balance is positive and the energy use in Jatropha production is efficient.

Jatropha constitutes one of promising species suitable for providing oil for biodiesel production. So, looking for good practice and sustainable use of energy during Jatropha cultivation and lack of information about Jatropha in Mozambique, this study pretends to estimate the energy balance in Jatropha plantation in Sun biofuel farm, by calculating the energy indicators based on a life cycle approach in Sun Biofuel farm located in Manica province, Central Mozambique. Energy balance is a tool which can help to calculate all energy indicators in order to evaluate and analyse the energy efficiency, sustainability and environmental benefits. This study estimated the indicator of energy balance namely: energy input is the sum of all energy used during the process of Jatropha cultivation and oil production, energy output is the amount of energy produced, Net energy value can be calculated subtracting the energy output from the energy input, Energy productivity is the division of Jatropha produced by the respective input energy, specific energy is the division of energy input by Jatropha seed output and energy ratio is the energy output divided by energy input. Also data was collected on the farm of Sun Biofuel to estimate the sustainability of agricultural production of the company. The Jatropha production in Sun Biofuel farm (SBF) absorbed around 28 579 MJ/ha of energy during the production and 121 820 MJ/ha of energy gain as result of the all production. The total energy input was direct energy with 77% and Indirect energy with 23% used in Jatropha farm, and also the total energy input was divided into renewable with 26% and non-renewable with 74% of its contribution. The results revealed that the contribution of seed husks was (8%), woody products (38%), raw seed oil (30%), Shell (9%) and press cake (15%) of total energy output in Jatropha oil production farm. Net energy value (NEV), energy productivity, energy use efficiency and Specific energy was 93 241 MJ ha-1, 0.067 Kg MJ-1, 4.3 and 15.04 MJ Kg-1, respectively. According to these results the energy balance is positive and the energy use in Jatropha production is efficient.

El cultivo de Jatropha curcas L. constituye una alternativa como fuente energética renovable. Limitado a zonas cálidas, las investigaciones ya realizadas sobre su aprovechamiento no aportan suficiente información para el conocimiento completo de su explotación agrícola, llegando a ser una especie no domesticada en la actualidad. La presente tesis doctoral tiene como objetivo principal estudiar la influencia de determinados factores agroecológicos en climas subtropicales secos que afectan al rendimiento en peso de semilla de J. curcas. Se estableció un diseño experimental multifactorial bajo condiciones de aridez en la zona suroeste de la República Dominicana, considerando la respuesta de 2 variedades frente a 2 niveles de abonado, altura de surco, escarda y marco de plantación, cuya combinación definió cada uno de los tratamientos ensayados. Para atender el diseño, se acondicionaron 96 cuadros experimentales, de 400 m2 cada uno. La variabilidad observada para los rendimientos obtenidos indica que la productividad respondió a los factores adoptados. Los mayores valores (760 Kg/Ha) se registraron para la variedad Cabo Verde, bajo una elevada frecuencia de escarda, menor marco de plantación (2,5x3 m), aporcado de surcos (de 30 cm de altura) y mayor dosis de abonado (150 Kg/Ha). El desarrollo vegetativo y fenológico del cultivo estuvo fuertemente condicionado por los aportes hídricos propios del periodo húmedo. Los datos microclimáticos registrados de la parcela experimental se mostraron similares a los históricos recopilados del municipio más cercano. Se verifica la elevada capacidad de propagación de J. curcas, obteniendo altos porcentajes de supervivencia tanto en la reproducción por semilla (90%) como por estaca (100%). Para este último caso, la aplicación de auxinas (IBA) propició un mayor desarrollo radicular, hecho más evidente a dosis más elevadas (5 mg/L). La eliminación de los componentes de la vegetación arvense en las parcelas de cultivo representa partidas costosas en los programas de explotación. Por ello se dedica un apartado a este subecosistema, realizando un estudio fitosociológico a partir del muestreo de inventarios y cálculo de los índices sintéticos. Se definieron 4 asociaciones distintas según las clasificaciones dicotómicas obtenidas, que reflejan las afinidades ecológicas Cultivo experimental de Jatropha curcas L. en condiciones áridas de la República Dominicana (Antonio Cerveró Domènech) entre las especies contempladas, de las que se elabora un catálogo florístico. Al final del documento se anexan otras especies determinadas taxonómicamente y que forman parte de la flora natural. Las plagas y enfermedades como subecosistema agrícola no tuvieron una incidencia significativa sobre el rendimiento del cultivo. Para el primer caso, aunque el control de ácaros resultó el de mayor dificultad, destacan los géneros Pachycoris sp. y Naupactus sp. por su distribución generalizada a lo largo del ciclo. Los daños causados por hongos se reducen al periodo de mayor humedad. Otro de los objetivos estudiados ha sido la fijación de CO2 del cultivo. Se determinó la capacidad sumidero de J.curcas al año y medio de edad para dicho gas, de aproximadamente 4 Tm CO2/Ha. En comparación con la especie más representativa de la vegetación natural P. juliflora, los resultados indican que para la zona elegida, ambas podrían fijar por superficie cantidades similares. La investigación finaliza con un apartado dedicado a la caracterización del aceite de la semilla. Tanto el contenido del mismo como los parámetros físico-químicos determinados (composición química, contenido en volátiles, carbono fijo y cenizas, y poder calorífico) mostraron valores similares para las muestras procedentes de distintas variedades, rendimientos en campo y edad de la plantación. El cultivo resultó viable. Sin embargo, es improbable que sin riego puedan alcanzarse resultados similares a los obtenidos en zonas con climas de mayor humedad, aspecto que contribuye a destacar la importancia de considerar el medio agroecológico. Para una óptima y rentable explotación, debe tenerse en cuenta la calidad del material vegetal y las labores agrícolas, como ha reflejado el efecto de los factores estudiados sobre el rendimiento. Los resultados obtenidos abren las puertas a continuar con la investigación y realizar más estudios acerca de la incidencia de los factores adoptados, evolución de la flora arvense como respuesta a la actividad antrópica, o el incremento de la productividad primaria de la planta, entre otros. / Cerveró Domènech, A. (2014). Cultivo experimental de Jatropha curcas L. en condiciones áridas de la República Dominicana [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48487

Parmi les technologies de solaire thermodynamique, la technologie du linéaire de Fresnel semble la plus adaptée aux régions d’Afrique Sub saharienne. Cela en raison de la simplicité de la technologie. C’est dans cette optique qu’un collecteur de type linéaire de Fresnel d’une superficie de 7,5 m² de miroirs a été construit au laboratoire énergies renouvelables et efficacité énergétique (LabEREE). La construction du collecteur s’est faite en utilisant en priorité les matériaux disponibles localement afinde rendre la technologie plus accessible aux populations locales et de réduire les coûts de fabrication. Des tests sont effectués sur le collecteur afin de déterminer ses rendements optiques, thermiques et globaux. Dans un premier temps, une revue bibliographie des différents collecteurs de type linéaire de Fresnel nous a permis d’identifier les variantes, de cette technologie, les plus adaptées au contexte dela région . Un modèle thermique et un modèle optique ont été mis en place comme outils de dimensionnement et d’optimisation du collecteur. Les résultats expérimentaux obtenus ont été utilisés pour valider les différents modèles mis en place. Le rendement global du collecteur obtenu expérimentalement est de 21% et il a un facteur de concentration local de 6. / Among the different technologies of concentrated solar power plant, the linear Fresnel, thanks to its simplicity, appears the most adapted to rural area of Sub Sahara region. A linear Fresnel collector of 7.5 m² has been built in “laboratoire énergies renouvelables et efficacité énergétique (LabEREE)”. The collector have been designed using material available locally by local man power. This reduces the total cost of the technology and makes it affordable for local population. The collector has been characterized in order to find optical, thermal and global efficiencies. In first time, a review on different linear Fresnel collector allows finding the technology that is most adapted to the Sub-Saharan region. An optical and thermal model of the collector has been done as a tool for designing and optimisation. The experimental results enable to validate the different models done. The collector has an effective concentration factor of 6 and a global efficiency of 21%.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2018-08-20T13:36:48Z No. of bitstreams: 2 Dissertação - Lidya Cardozo da Silva - 2018.pdf: 2382834 bytes, checksum: e5a79619d923d442540c5bf0549318bd (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-08-20T13:38:04Z (GMT) No. of bitstreams: 2 Dissertação - Lidya Cardozo da Silva - 2018.pdf: 2382834 bytes, checksum: e5a79619d923d442540c5bf0549318bd (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-08-20T13:38:04Z (GMT). No. of bitstreams: 2 Dissertação - Lidya Cardozo da Silva - 2018.pdf: 2382834 bytes, checksum: e5a79619d923d442540c5bf0549318bd (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-07-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Jatropha curcas L. is a euphorbiaceous oilseed plant considered toxic to humans and animals due to the presence of phorbol esters (PEs). Traditionally, the detection of these toxic compounds has been done in J. curcas seeds and derivates via chromatographic separation methods such as HPLC-UV and HPLC-MS. Although efficient, these techniques are laborious and require high time and solvent consumption, thus it would be interesting the development of new analytical methods to determine these compounds with more practicality. Probe electrospray ionization is frequently used in ambient mass spectrometry allowing analysis with minimum sample preparation. However, for complex samples analysis, this technique presents low sensitivity and ionization suppression. In this study, a molecularly imprinted polymer-coated probe electrospray ionization mass spectrometry (MIPCPESI-MS) method was developed for determination of phorbol esters in methanolic extracts of Jatropha curcas leaves with direct extraction form the ionization source. The synthesized molecularly imprinted polymer (MIP) proved to be adequate for extraction of the PEs in methanolic extracts of J. curcas leaves with better performance as extraction phase in comparison with the non-imprinted polymer (NIP). The MIPCPESI method allowed detection of phorbol 12,13-diacetate (PDA) and other three PEs metabolite ions from Jatropha leaves with minimal sample preparation, and with higher signal intensities compared to analysis with conventional PESI. For the PDA, calibration curve exhibited linearity with R2 > 0.99, LOD and LOQ in µg.mL-1 range, precision and accuracy values, respectively, between 4.06 to 13.49% and -1.60 to -15.26 %. Finally, MIPCPESI was employed for PDA quantification in methanolic extracts of six different J. curcas leaves genotypes resulting in concentrations ranging from 222.19 ± 23.55 to 528.23 ± 19.72 µg.g-1 for toxic samples. / A Jatropha curcas L. é uma oleaginosa euforbiácea considerada tóxica para humanos e animais devido à presença de ésteres de forbol (PEs). Tradicionalmente, a detecção destes compostos tóxicos tem sido feita em tortas e sementes de J. curcas por meio do uso de técnicas de separação cromatográfica como HPLC-UV e HPLC-MS que apesar de eficientes são laboriosas e requerem alto consumo de tempo e solventes. Dessa forma, seria interessante o desenvolvimento de novas técnicas analíticas para determinação desses compostos com maior praticidade. Probe electrosrpay ionization (PESI) é uma das técnicas de ionização utilizadas na espectrometria de massas ambiente que permite análises rápidas com mínimo preparo de amostras. No entanto, para análise de amostras complexas essa técnica apresenta baixa sensibilidade e supressão iônica. Neste estudo, foi desenvolvido um método de análise por espectrometria de massas por Probe electrospray revestido com polímero molecularmente impresso (MIPCPESI-MS) para determinação de ésteres de forbol em extratos metanólicos de folhas de Jatropha curcas com extração direta da fonte de ionização. O polímero molecularmente impresso (MIP) sintetizado mostrou-se adequado para extração de PEs em extratos metanólicos de folhas de J. curcas tendo melhor desempenho como fase extratora quando comparado ao polímero não molecularmente impresso (NIP). O método MIPCPESI-MS possibilitou a detecção do forbol 12,13-diacetato (PDA) e de outros três íons metabólitos presentes nas folhas de J. curcas com mínimo preparo de amostras e com maior intensidade de sinais quando comparado às análises com PESI convencional. Para o PDA, a curva de calibração apresentou linearidade com R2 > 0.99, LOD e LOQ na faixa de µg.mL-1, valores de precisão entre 4.06 e 13.49 % e exatidão entre -1.60 e -15.26 %. Posteriormente, o método MIPCPESI foi empregado na quantificação de PDA em seis extratos metanólicos de diferentes genótipos de folhas de J. curcas resultando em valores concentrações entre 222.19 ± 23.55 a 528.23 ± 19.72 µg.g-1 nas amostras tóxicas.