Browsing Artículos científicos by Title
Now showing items 131-150 of 190
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Key drivers controlling stable isotope variations in daily precipitation of Costa Rica: Caribbean Sea versus Eastern Pacific Ocean moisture sources
(Elsevier, 2016)Costa Rica is located on the Central American Isthmus, which receives moisture inputs directly from the Caribbean Sea and the Eastern Pacific Ocean. This location includes unique mountainous and lowland microclimates, but ... -
Key hydrological processes in the Del Azul Creek basin, sub-humid Pampean Plain
(Elsevier B.V., 2021-02)Groundwater plays an important role in the economic development of the Chaco-Pampean Plain (Argentina), where industry, agriculture and cattle farming are the main economic activities. The 66% of the country's population ... -
Kinetics of anaerobic degradation of screened dairy manure by upflow fixed bed digesters: Effect of natural zeolite addition
(Taylor & Francis, 2009)The effect of the hydraulic retention time (HRT) on the performance of two up-flow anaerobic fixed bed digesters (UFAFBDs) packed with waste tire rubber (D1) and waste tire rubber and zeolite (D2) as micro-organism ... -
Kinetics of Isothermal Degradation Studies in Adhesives by Thermogra vimetric Data: Effect of Hydrophilic Nanosilica Fillers on the Thermal Properties of Thermoplastic Polyurethane-Silica Nanocomposites
(Recent Patents on Nanotechnology, 2008)The kinetics of thermal degradation process on thermoplastic polyurethanes (TPUs) adhesives with hydrophilic nanosilicas was studied using isothermal thermogravimetric analysis within the temperature range from 360 °C ... -
Lead acid battery recycling in Costa Rica: A case study
(WIT Transactions on Ecology and the Environment, 2012)This work describes the production of secondary lead in a smelter located in Costa Rica. The only input of the plant is scrap automotive batteries. We describe the environmental management strategies used for waste ... -
Manejo de Mercancías Químicas peligrosas en puerto Caldera, Puntarenas, Costa Rica
(Universidad Nacional (Costa Rica), 2009)Puerto Caldera, ubicado en Puntarenas, Costa Rica, en uno de los puertos más importantes de Centroamérica, ya que a través de él se trasiegan por año aproximadamente 1.5 millones de toneladas métricas de carga de diferentes ... -
Maxonine, a novel alkaloid from Simira maxonii
(Elsevier, 1989)A novel alkaloid, maxonine, with an indole-pyrido-naphthyridine skeleton, has been isolated from . Its structure was elucidated on the basis of 2D NMR spectral data. A novel alkaloid, maxonine (1), with an indolepyrido-n ... -
Medicinal Water? The occurrence and fate of pharmaceuticals in aquatic environments A short communication
(Universidad Nacional (Costa Rica), 2012)Although very little is known about the transport, fate and toxic effects of medical compounds in aquatic environments, the presence of these compounds in potable water sources can no longer be overlooked. We can ... -
Methane Dynamics in a Tropical Serpentinizing Environment: The Santa Elena Ophiolite, Costa Rica
(Universidad Nacional (Costa Rica), 2017)Uplifted ultramafic rocks represent an important vector for the transfer of carbon and reducing power from the deep subsurface into the biosphere and potentially support microbial life through serpentinization. This ... -
Modelling non-stationary water ages in a tropical rainforest: A preliminary spatially distributed assessment
(John Wiley and Sons Ltd, 2020)Pristine tropical forests play a critical role in regional and global climate systems. For a better understanding of the eco-hydrology of tropical “evergreen” vegetation, it is essential to know the partitioning of water ... -
Moisture transport and seasonal variations in the stable isotopic composition of rainfall in Central American and Andean Páramo during El Niño conditions (2015–2016)
(John Wiley and Sons Ltd, 2019)High‐elevation tropical grassland systems, called Páramo, provide essential ecosystem services such as water storage and supply for surrounding and lowland areas. Páramo systems are threatened by climate and land use ... -
Monitoreo de la concentración de SO2 en el aire y características físicoquímicas del agua de lluvia en el Volcán Irazú
(Tecnológico de Costa Rica, 2021-10)El dióxido de azufre y otros contaminantes químicos pueden llegar a la naturaleza y el ambiente por medio de la actividad volcánica. Debido a esto, en Costa Rica, las zonas cercanas a los volcanes se encuentran afectadas ... -
Nanochitin: Chemistry, Structure, Assembly, and Applications
(ACS Publications, 2022)Chitin, a fascinating biopolymer found in living organisms, fulfills current demands of availability, sustainability, biocompatibility, biodegradability, functionality, and renewability. A feature of chitin is its ability ... -
National Inventory of Mercury Release into Different Environmental Sectors Estimated by United Nations Environment Programme (UNEP) Toolkit in Costa Rica
(United Nations Environment Programme (UNEP) Toolkit, 2017)This paper summarizes the national inventory of mercury released into all environmental sectors (air, water, land, impurity in products, general wastes and sector specific treatment/disposal) for the year 2008 in the country ... -
Neutralización del efceto hemorrágico inducido por veneno Bothrops asper (Serpentes: Viperidae) por extractos de las plantas tropicales
(Universidad Nacional (Costa Rica), 1999)Organic extracts representing 48 species included in 30 families of Costa Rican tropical plants were evaluated for their hability to neutralize hemorrhagic acfivity lnduced by the venom of the snake Bothrops aspero Abioassay ... -
New advances in the method validation, extraction methods and measurement uncertainty for the determination of water-soluble hexavalent chromium in hydraulic cemen
(Elsevier, 2021)The quantification of Cr (VI) in the cement matrix is highly important, given the possibility of suffering illnesses including dermatitis, induced nasal carcinoma, and DNA damage produced by inhalation of and/or direct ... -
New advances in the method validation, extraction methods and measurement uncertainty for the determination of water-soluble hexavalent chromium in hydraulic cement
(Elsevier Ltd, 2021-04-20)The quantification of Cr (VI) in the cement matrix is highly important, given the possibility of suffering illnesses including dermatitis, induced nasal carcinoma, and DNA damage produced by inhalation of and/or direct ... -
Nutritional and bioactive composition of Spanish, Valencia, and Virginia type peanut skins
(Academic Press Inc., 2021-01-21)The aims of this study were to determine the proximate and amino acid compositions, mineral content, and fatty acid and proanthocyanidins (PAC) profiles of peanut skins (PS) from three varieties of peanuts. Proximate ... -
Obtención de acetato de celulosa a partir de desechos agroindustriales
(Universidad Nacional [Costa Rica], 1989-01-01)El propósito del presente trabajo fue encontrar usos alternativos para los residuos agrícolas. Se realizó la acetilación de celulosa de cáscara de piña, cáscara de arroz y aserrín. La reacción de acetilación se llevó a ... -
Obtención de lignina y celulosa de residuos de maíz
(Universidad Nacional, Costa Rica, 1992-01-01)Mediante un método de pulpeo sencillo se obtuvo la lignina y la celulosa de tusa y olote de maíz con buenos rendimientos. Los estudios de termogravimetría mostraron que estas ligninas son térmicamente menos estables que ...