Refine search
Results 2641-2650 of 26,567
Desarrollo del Agua Subterranea en el valle Viru
1967
Marquina Neyra, Enrique | Fuentes Melgar, Wilbert
A determinação da água livre em substâncias puras Full text
1967
Catani, R.A.(ESALQ) | Alcarde, J.C.(ESALQ) | Furlani, P.R.
This paper reports the study of the free water determination in CaSO4. 2H2O, Ca(H2PO4). H2O, CaHPO4.2H2O, (NH4)2HPO4, NaCl and in urea by the classical method of ovendryxng at 100-105°C and by the vacuumdessication method at 50°C in oven under vacuum of 20 inches. The vacuum-dessication method gave best results than the oven-drying (100-105ºC) method when the hydrated salts were analysed. | O presente trabalho relata os dados obtidos sôbre a determinação da água livre em diversas substâncias puras pelo método baseado no uso da estufa comum a 100-105ºC (método clássico) e pelo método que usa 20 polegadas (ou 50 mm de mercúrio) de vácuo a 50°C. As substâncias empregadas foram cloreto de sódio, sulfato de cálcio dihidratado, ortofosfato monocálcico monohidratado, ortofosfato bicálcico dihidratado, ortofosfato monácido de amônio e uréia cristalizada. Os resultados obtidos permitem concluir que o método que usa estufa a vácuo a 50°C apresenta uma tendência de retirar apenas a água livre das substâncias estudadas. Por outro lado, o método clássico que emprega estufa comum a 100-105°C, além da água livre, retira também uma fração variável da água de hidratação ou de cristalização das substâncias que a contém.
Show more [+] Less [-]Evapotranspiraciones potenciales y balances de agua en España
1965
Elías Castillo, Francisco | Giménez Ortiz, Rafael
El agua subterránea en la zona de Lima Full text
1963
Brinda una visión general sobre la situación del agua subterránea en Lima, en base a datos de campo así como cálculos estimativos.
Show more [+] Less [-]Algas de agua dulce del llano del Llobregat Full text
1940
Margalef, Ramón
18 pages, 1 table | Las siguientes notas se refieren a la flora algológica de los estanques, acequias, canales, zanjas y charcos que surcan los campos del llano del Llobregat, en las proximidades de la desembocadura del río. Las estaciones estudiadas, la mayoría a la derecha del Llobregat, se distribuyen en una extensión de 20 Km2, aproximadamente, comprendida entre la costa dos líneas convergetnes en el pueblo del Prat, de dirección E-O y NE-SO. [...] | Peer reviewed
Show more [+] Less [-]Tarifa de agua superficial con fines no agrarios
Otero Cisneros, Luis
Tratamiento de semilla de jitomate con agua caliente Full text
Díaz, Cristian Nava
El jitomate (Lycopersicum esculentum Mill.) es un cultivo muy importante.
Show more [+] Less [-]Tecnologias de desinfeccion del agua para consumo humano Full text
Roosa,Danielle Malek
Honduras has collected promising and interesting experiences in common disinfection of the water supply for consumption in rural and urban communities. Honduras has been responsible for introducing and developing community technologies such as chlorination by tablet and by solar disinfection (SODIS) to substantially reduce infant deaths caused by water-borne diseases. This document includes the following headings: presentation; description of the projects; the challenge of water disinfection in Honduras; water disinfection methods in public systems; water disinfection methods at the household level; and SODIS pilot projects in Honduras.
Show more [+] Less [-]Temporal variations in groundwater nitrogen under intensive groundwater/surface-water interaction | Variations temporelles de l’azote des eaux souterraines sous forte interaction entre les eaux souterraines et les eaux de surface Variaciones temporales del nitrógeno en el agua subterránea bajo una intensiva interacción agua subterránea/agua superficial 强烈的地下水—地表水相互作用下地下水氮的季节性变化 Variação temporal do nitrogênio nas águas subterrâneas sob intensa interação água subterrânea/água superficial Full text
2019
Shen, Shuai | Ma, Teng | Du, Yao | Luo, Kewen | Deng, Yamin | Lu, Zongjie
Nitrogen (N) pollution in shallow groundwater within the Jianghan Plain—a depositional basin along the Yangtze River in China—is a serious issue affecting the local water supply. There is little concern regarding temporal variation patterns of groundwater N in regions with intensive groundwater/surface-water interactions thus far. In this study, a 2-year field monitoring program and a set of incubation experiments were jointly applied to characterize the seasonal variation mechanisms of groundwater N. Groundwater monitoring suggested that temporal N variations in monitoring wells of 25 and 10-m depth were correlated with fluctuations in water levels, with lower NH₄-N and higher NO₃⁻-N concentrations corresponding to groundwater discharge during the dry season, and with higher NH₄-N and lower NO₃⁻-N concentrations corresponding to groundwater recharge during the wet season. Batch sediment incubation experiments showed that buried organic carbon in sediments from the field site could not promote NH₄-N release, but exogenous organic carbon and oxidant input could catalyze organic N mineralization, resulting in NH₄-N release. Nevertheless, NO₃⁻-N release was limited in all incubations. Thus, the temporal variation patterns could be divided into (1) groundwater N in type-1 wells (25 and 10 m), controlled by the annual reversal of groundwater flow gradient, which determined whether there was input of exogenous organic carbon or oxidants, ultimately affecting organic N mineralization, denitrification and other transformation processes, and (2) groundwater N in type-2 wells (<4 m depth), which showed no significant seasonal variation, implying the process is mainly controlled by surface inputs in the shallower subsurface.
Show more [+] Less [-]Agua en Macondo : arreglos institucionales para la gobernanza del recurso hídrico en la cuenca del río Aracataca, Magdalena | Water in Macondo : institutional arrangements for water governance in the Aracataca river basin (Magdalena, Colombia) Full text
2020
Fonseca Cepeda, Valentina | Castillo Brieva, Daniel | Vilardy Quiroga, Sandra | Rodríguez Ramírez, Luz Ángela
La ecorregión de la Ciénaga Grande de Santa Marta conforma un complejo de humedales y redes hídricas que se caracteriza por su alta productividad y los diversos sistemas de uso de la biodiversidad ligados al agua. Parte de los cambios que han ocurrido en la ecorregión, se deben a las transformaciones en las dinámicas del agua dulce que entra al sistema deltáico a través de los ríos que descienden de la Sierra Nevada. Esta investigación indagó sobre el sistema de gobernanza del agua y su relación con la sostenibilidad a través de un estudio de caso en la cuenca del río Aracataca como sistema socioecológico. El estudio combinó datos cuantitativos obtenidos de la descripción hidrológica de la cuenca, así como datos cualitativos derivados de entrevistas y un juego de rol, los cuales fueron analizados desde la perspectiva socioecológica y el análisis de desarrollo institucional. El análisis evidenció que el manejo histórico del agua ha establecido un escenario problemático definido por tensiones entre intereses individuales y colectivos, heterogeneidad entre actores, e ineficiencia en los mecanismos de monitoreo y sanción. La configuración actual del sistema evidencia problemas de gobernanza antes que de escasez de agua a escala anual, los cuales requieren de cambios estructurales que permitan el desenvolvimiento de procesos de coordinación hacia la acción colectiva. La investigación identificó elementos de interés para enriquecer los discursos sobre la gestión de la Ciénaga Grande de Santa Marta, destacando la importancia de entender los problemas de conservación de la biodiversidad como problemas de recursos de uso común. | OPAL Oil Palm Adaptive Landscapes | Cuenca del río Aracataca | The Ciénaga Grande de Santa Marta forms a complex of wetlands and water networks characterized by its high productivity and the diverse biodiversity use systems linked to water. Changes in the region are in part due to changes in the fresh water dynamics that enters the deltaic system through the rivers that descend from the Sierra Nevada. This research described the water governance system and its relationship with sustainability through a case study in the Aracataca river basin as a socio-ecological system. The study combined quantitative data obtained from the hydrological description of the basin, as well as qualitative data derived from interviews and a role playing game, which were analyzed from the socio- ecological perspective and the institutional analysis of development. The analysis showed that the historical management of water has established a problematic scenario defined by conflicts between individual and collective interests, heterogeneity between actors, and inefficiency in monitoring and sanctioning mechanisms. The current configuration of the system shows governance problems rather than water shortages on an annual scale, which require structural changes that allow the development of coordination processes towards collective action. The research identified elements of interest to enrich the discourses on the management of the Ciénaga Grande de Santa Marta, highlighting the importance of understanding conservation problems as common-pool resources problems. | Magíster en Conservación y Uso de la Biodiversidad | Maestría
Show more [+] Less [-]