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Analisis termodinamico de un sistema de refrigeracion solar por absorción usando soluciones de monometilamina - agua para la conservación de alimentos Texte intégral
2010
Cesar Isaza | Isaac Pilatowsky | Rosemberg Romero | Farid Cortés
Este trabajo presenta la viabilidad de los sistemas de refrigeración solar por absorción usando soluciones de monometilamina - agua (MMA-A) para aplicaciones en conservación de alimentos en las regiones rurales de Colombia, sin acceso a la red de energía eléctrica. Para suplir los re- guerímientos de energía térmica se propone un sistema de calentamiento de agua con energía solar usando colectores de placa y un sistema de respaldo convencional. En este trabajo se determinó el coeficiente de operación (COP) del sistema de refrigeración solar por absorción de una sola etapa en función de la temperatura en los diferentes componentes del ciclo. Los resultados indican gue el sistema podría mejorarse mediante un mejor diseño en el intercambiador de calor de solución, el evaporador y el rectificador Los resultados teóricos demuestran gue el uso de la solución de MM/4-/4 puede ser usada en sistemas de refrigeración por absorción operados con energía térmica de baja calidad, tales como la energía solar
Afficher plus [+] Moins [-]Retention of aroma compounds: an interlaboratory study on the effect of the composition of food matrices on thermodynamic parameters in comparison with water Texte intégral
2010
Kopjar, Mirela | Andriot, Isabelle | Saint-Eve, Anne | Souchon, Isabelle | Guichard, Elisabeth
BACKGROUND: Partition coefficients give an indication of the retention of aroma compounds by the food matrix. Data in the literature are obtained by various methods, under various conditions and expressed in various units, and it is thus difficult to compare the results. The aim of the present study was first to obtain gas/water and gas/matrix partition coefficients of selected aroma compounds, at different temperatures, in order to calculate thermodynamic parameters and second to compare the retention of these aroma compounds in different food matrices.RESULTS: Yogurts containing lipids and proteins induced a higher retention of aroma compounds than model gel matrices. The observed effects strongly depend on hydrophobicity of aroma compounds showing a retention for ethyl hexanoate and a salting out effect for ethyl acetate. A small but noticeable decrease in enthalpy of affinity is observed for ethyl butyrate and ethyl hexanoate between water and food matrices, suggesting that the energy needed for the volatilization is lower in matrices than in water.CONCLUSION: The composition and complexity of a food matrix influence gas/matrix partition coefficients or aroma compounds in function of their hydrophobicity and to a lower extent enthalpy of vaporization.
Afficher plus [+] Moins [-]Retention of aroma compounds: an interlaboratory study on the effect of the composition of food matrices on thermodynamic parameters in comparison with water Texte intégral
2010
Kopjar, Mirela | Andriot, Isabelle | Saint Eve, Anne | Souchon, Isabelle | Guichard, Elisabeth | FLAveur, VIsion et Comportement du consommateur (FLAVIC) ; Etablissement National d'Enseignement Supérieur Agronomique de Dijon (ENESAD)-Institut National de la Recherche Agronomique (INRA)-Université de Bourgogne (UB) | Faculty of Food Technology ; University of Osijek | Génie et Microbiologie des Procédés Alimentaires (GMPA) ; Institut National de la Recherche Agronomique (INRA)-AgroParisTech
Research Article | Partition coefficients give an indication of the retention of aroma compounds by the food matrix. Data in the literature are obtained by various methods, under various conditions and expressed in various units, and it is thus difficult to compare the results. The aim of the present study was first to obtain gas/water and gas/matrix partition coefficients of selected aroma compounds, at different temperatures, in order to calculate thermodynamic parameters and second to compare the retention of these aroma compounds in different food matrices.RESULTS: Yogurts containing lipids and proteins induced a higher retention of aroma compounds than model gel matrices. The observed effects strongly depend on hydrophobicity of aroma compounds showing a retention for ethyl hexanoate and a salting out effect for ethyl acetate. A small but noticeable decrease in enthalpy of affinity is observed for ethyl butyrate and ethyl hexanoate between water and food matrices, suggesting that the energy needed for the volatilization is lower in matrices than in water.CONCLUSION: The composition and complexity of a food matrix influence gas/matrix partition coefficients or aroma compounds in function of their hydrophobicity and to a lower extent enthalpy of vaporization.
Afficher plus [+] Moins [-]Ethiopia Nile Basin Climate Change Adaptation Dataset | Food and water security under global change: Developing adaptive capacity with a focus on rural Africa Texte intégral
2012 | 2010 | 2015
The household survey was carried out in the Nile River Basin in Ethiopia. The household sampling frame in Ethiopia was developed to ensure representation for the Nile River Basin at the woreda (district) level regarding level of rainfall patterns in terms of both annual total and variation; the four classes of traditionally defined agro-ecological zones (AEZs) found in the basin; vulnerability of food production systems (through the proxy of frequency of food aid in the past ten years); and irrigation prevalence. All data used for the sample frame is from the Atlas of the Ethiopian Rural Economy (Benson et al., 2006).; Each woreda was classified based on : agroecological zone (Kolla, Weynadega, Dega, and Bereha), the percent of cultivated land under irrigation (no data, 0-2%, 2-4%, 4-8%, and 8% or greater), average annual rainfall (0-854mm, 854-1133mm, 1133-1413mm, 1413-1692mm, 1692mm or greater), rainfall variability (coefficient of variation for annual rainfall), and vulnerability (number of years of food aid received in the past 10 years). ;Twenty woredas were selected such that across each of the above dimensions the proportion falling into each class for the sample matched as closely as possible the proportions for the entire Ethiopian Nile basin. Peasant associations (administrative units lower than districts) were also purposely selected to include households that irrigate their farms. One peasant association was selected from every woreda for a total of 20 peasant associations. Random sampling was used in selecting 50 households from each peasant administration within the 20 woredas. Thus, the final dataset contains 1,000 observations from 20 woredas in 5 regional states in Ethiopia (Tigray, Amhara, Oromiya, Benishangul Gumuz, and Southern Nations Nationalities and Peoples (SNNP)). | IFPRI1 | EPTD | The survey was conducted by the Ethiopian Development Research Institute (EDRI), in collaboration with the International Food Policy Research Institute (IFPRI). Funding for the survey was provided by the Federal Ministry for Economic Cooperation and Development (Germany). The project forms part of the Consultative Group on International Agricultural Research (CGIAR)’s Challenge Program on Water and Food (CPWF).; Dataset Citation: Food and Water Security under Global Change: Developing Adaptive Capacity with a Focus on Rural Africa— Ethiopia Nile Basin Climate Change Adaptation dataset. 2010. Washington, D.C.: International Food Policy Research Institute (IFPRI) (datasets).; Data file format(s): STATA, EXCEL; Principal contact: Yan Sun; Principal researcher: Claudia Ringler
Afficher plus [+] Moins [-]Comparación de energías y gases de efecto invernadero en calentamiento de agua para cocción de alimentos con electricidad y gas natural Texte intégral
2010
González, Alejandro Daniel
En este trabajo se estudia la energía usada y los gases de efecto invernadero emitidos en el calentamiento de agua destinado a la alimentación en los hogares. El objetivo es comparar los usos finales de electricidad y de gas natural. Se obtuvieron los rendimientos para calentamiento de agua en cocinas convencionales a gas natural, cocinas eléctricas de plato, y calentadores de agua eléctricos de inmersión. Los rendimientos de calentamiento de agua en el hogar fueron entre 29% y 62% para uso de gas natural, y entre 72% y 96% para el uso de electricidad. Para la electricidad se estudió el balance energético de la red troncal de Argentina que combina el uso de recursos fósiles, hidroeléctrico y nuclear. Cuando se consideran las eficiencias de la generación eléctrica, este recurso resulta menos conveniente que el gas para cocción en ollas, pero no así para el calentamiento de agua en tiempos cortos. | The aim of this work is to study the energy used and the greenhouse gas emissions associated with water heating in households. The objective is to compare end-use efficiencies for gas and electricity used in cooking. Experiments to obtain water heating efficiencies by using a custom natural gas appliance, a hot plate electrical device, and other electrical heaters have been performed. End-use efficiencies for water heating with gas were in the range of 29% to 62%, while for electricity were 72% to 96%. To assess the actual impact of electricity the generation stage in Argentina was studied, which combines fossil, as well as hydro and nuclear resources. When the efficiencies for generating electricity were considered, the use of natural gas turn to be more convenient than electricity for cooking, but the opposite was found when quick water heating in kettles is required. | Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES)
Afficher plus [+] Moins [-]South Africa Limpopo Basin Climate Change Adaptation Dataset | Food and water security under global change: Developing adaptive capacity with a focus on rural Africa Texte intégral
2012 | 2010 | 2015
Ringler, Claudia; Sun, Yan
External publication used this dataset: Oyekale, Abayomi Samuel; and Vutela-Tekana, Sibongile Sylvia. 2012. A factor component analysis of the sources of income inequality in the Limpopo River Basin of South Africa. Life Science Journal 9(3): 720-725. http://www.lifesciencesite.com/lsj/life0903/101_8983life0903_720_725.pdf | This household survey was conducted as part of a project aimed to provide policymakers and stakeholders in South Africa with tools to better understand, analyze, and form policy decisions to adapt to global change. The survey was conducted in the Limpopo River Basin in South Africa during 2005. A total of 794 households from 19 districts, in 5 Water Management Areas (WMAs), across 4 provinces of South Africa were sampled. The South Africa sample was designed to capture the diverse agricultural patterns in the basin area: farming strata, type of cultivation (dry land and irrigation), major and minor crops and livestock, and all the sub-catchment areas in each of the 5 WMAs. Topics covered include household roaster including background information, farm and non-farm activities, assets, basic services, disease, shocks; land ownership and land holdings; farm machinery, farm buildings, wells and pumps, and wage rates; crop production including production cost and income for seasonal crops and for perennial crops; crop water use; livestock production; access to extension, markets and credit; expenditures on food and income; and climate change and adaptation options. | IFPRI1 | EPTD | The survey was conducted by the Center for Environmental Economics and Policy in Africa (CEEPA), University of Pretoria, in collaboration with the International Food Policy Research Institute (IFPRI). Funding for the survey was provided by the Federal Ministry for Economic Cooperation and Development (Germany). The project forms part of the Consultative Group on International Agricultural Research (CGIAR)’s Challenge Program on Water and Food (CPWF).; Dataset Citation: Food and Water Security under Global Change: Developing Adaptive Capacity with a Focus on Rural Africa. South Africa Limpopo Basin Climate Change Adaptation dataset. 2010. Washington, D.C.: International Food Policy Research Institute (IFPRI) (datasets).; Data file format(s): STATA, EXCEL; Principal contact: Yan Sun; Principal researcher: Claudia Ringler
Afficher plus [+] Moins [-]Utilization of membrane filtration for preconcentration and determination of Cu(II) and Pb(II) in food, water and geological samples by atomic absorption spectrometry Texte intégral
2010
Soylak, Mustafa | Unsal, Yunus Emre | Kizil, Nebiye | Aydın, Ayşe
A method for separation–preconcentration of Cu(II) and Pb(III) ions by membrane filtration has been presented. The analyte ions were collected on acetate membrane filter as their 1-2-pyridylazo 2-naphthol (PAN) complexes. The analytes were determined by flame atomic absorption spectrometry. The analytical parameters including pH, eluent type, sample volume, amount of PAN, etc. were examined in order to gain quantitative recoveries of analyte ions. The effects of foreign ions on the recoveries of analyte ions were also investigated. The detection limits by three sigma were found to be 1.2 and 3.5 μg L−1 for Cu(II) and Pb(II), respectively. The preconcentration factor was 60 for Cu(II) and 20 for Pb(II). The validation of the presented procedure was checked by the analysis of certified reference materials. The optimized method was successfully applied to food, water and geological samples with good results.
Afficher plus [+] Moins [-]EU Legislation on Food and Potable Water Safety which could be Potentially Applied on Board Ferries and Cruise Ships: A Comparison with US Legislation
2010
Arvanitoyannis, Ioannis | Hadjichristodoulou, Christos | Tserkezou, Persefoni | Mouchtouri, Varvara | Kremastinou, Jenny | Nichols, Gordon
The high number of people moving around by ferries and cruise ships in conjunction with great amounts of food and potable water transported (occasionally overloaded) and consumed by passengers constitute a possible risk for communicable diseases. Another issue of equally great importance is the food handlers who come from diverse origin and have a different mentality, habits, and background. In this paper an attempt is made to present comparatively EU and US legislation that could be potentially applicable to passenger ships food premises and potable water supplies. Moreover, food and water related hazards, not currently covered by EU legislation, were assessed together with US legislation and other guidelines for cruise ships.
Afficher plus [+] Moins [-]Efecto de la adición de minerales en agua o en alimento sobre variables productivas y fisiológicas en pollos de engorde bajo estrés calórico Texte intégral
2010
Farfán, Charly(Universidad Central de Venezuela Facultad de Agronomía Instituto de Producción Animal) | Oliveros, Yngrid(INIA CENIAP) | De Basilio, Vasco(Universidad Central de Venezuela Facultad de Agronomía Instituto de Producción Animal)
A través de un experimento con 192 pollos mantenidos a 30°C en promedio de temperatura ambiente (TA) entre 28 días y 35 días, se evaluó el efecto de la adición de minerales en el agua o el alimento sobre las variables productivas y fisiológicas durante la etapa de finalización, bajo condiciones de estrés calórico crónico y agudo en pollos de engorde. Luego se simuló a los 36 días de edad, el estrés agudo con 36 °C/6 horas, incluyendo 3 tratamientos: T1= Alimento balanceado sin adición mineral, T2= Alimento balanceado con adición mineral en alimento y T3= Alimento balanceado con adición mineral en agua. El diseño experimental fue un arreglo completamente al azar, con 8 repeticiones/tratamiento, 8 pollos/repetición. La composición del suplemento mineral fue: NaHCO3 (0,83%); NH4Cl (0,07%) y; NaCl (0,30%), obteniéndose un balance de electrólitos de 240 mEq. Se evaluaron, el consumo de alimento, consumo de agua, ganancia de peso, conversión de alimento, temperatura corporal (TC), nivel de hiperventilación (NH), durante el estrés crónico y mortalidad (M) durante el estrés agudo. Los datos fueron analizados mediante pruebas de ANAVAR y de Chicuadrado para la mortalidad. Encontrándose que al adicionar minerales tanto en el agua como en el alimento, no hubo efecto significativo en las variables productivas. Se observó que los pollos que recibieron minerales (T2 y T3), incrementaron el consumo promedio de agua en un 34% (P=0,016) con respecto al T1. La adición de minerales en el agua permitió una disminución (P=0,007) de la TC (42,80 ± 0,16 °C), NH (159,95 ± 4,93 insp/min) y una reducción de la M hasta un 22% durante la simulación del estrés calórico agudo. Se concluye que la adición de minerales afecta principalmente las variables fisiológicas y la mortalidad | In order to evaluate the effect of mineral supplying in water or feed on productive and physiological variables in broilers under acute and chronic heat stress during final growth stage an experiment was conducted. Using a completely randomized design, a total of 195 broilers were randomly assigned to three treatments with 8 replicates of 8 birds each one. The treatments were T1 = basal diet with no mineral addition; T2 = basal diet plus mineral addition in feed; T3 = basal diet plus mineral addition in water, which were applied from 28 days of age. Before this period all broilers were receiving a same balance diet. The composition of the mineral formula used was: NaHCO3 (0,83%); NH4Cl (0,07%); NaCl (0,30%), obtaining an electrolytes balance of 240 mEq. Between 28 to 35 days of age, all these groups of birds were subjected at 30 ºC and the following day an acute heat stress was simulated using 36ºC for 6 hours. At 28 to 36 days old the following parameters were measured: feed and water consumption, body weight gain, feed conversion index, body temperature (BT), hyperventilation level (HL) and mortality (M) during acute stress. An ANOVA test was applied to all variables except M, which a Chi-squared test was performed. No significant effects on productive variables were found with minerals adding, neither to the water nor to the feed. Water consumption was 34% greater in T3 and T2 (P=0,016) regard to T1, which not received minerals. Mineral addition in water reduced significantly (P=0,007) BT (42,80 ± 0,16 °C), HL (159,95 ± 4,93 breaths/min) and M was reduced until 22% during acute heat stress period. It is concluded that mineral supplying affects mostly physiological variables and mortality
Afficher plus [+] Moins [-]Adaptation options to reduce the vulnerability of Mekong water resources, food security and the environment to impacts of development and climate change. Report to AusAID Texte intégral
2010
Mainuddin, M. | Hoanh, Chu Thai | Jirayoot, K. | Halls, A.S. | Kirby, M. | Lacombe, Guillaume | Srinetr, V.
The report aims to provide critical input to the Mekong River Commission's (MRC) regional Climate Change and Adaptation Initiative (CCAI) which was launched shortly after the formulation of this project. The CCAI is a collaborative regional initiative designed to address the shared climate change adaptation challenges of LMB countries in response to the potential effects of climate change on the socio-economic characteristics and natural resources of the LMB region. MRC has identified need for a more informed understanding of the potential impacts from climate change. To contribute to this aim, the purpose of this report is: 1. To present the framework of climate change analysis and its application to the Basin Development Plan (BDP) Scenarios; 2. To present the results from the application of the Decision Support Framework (DSF) models of the Mekong River Commission (MRC) in order to analyse the impacts of climate change and selected BDP Scenarios on flow regimes; 3. To present climate change impacts on floods and fisheries in the LMB; 4. To present the impact of climate change on the productivity of major crops grown in the basin and their consequences on the overall food security of the basin considering future population growth. 5. To present the results of applying simple adaptation strategies related to agriculture and food security; and 6. To determine further studies necessary to identify suitable adaptation strategies for dealing with such impacts.
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