Browsing Artículos científicos by Issue Date
Now showing items 1-20 of 38
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Orientation effect in poly (butylene succinate) fibers
(Polymers & Polymer Composites vol.11 no.1 51-56 2003, 2003)Fibers of poly (butylene succinate) (PBS) were prepared using a single screw extruder at various take-up speeds. Changes in fiber structure, morphology and physical properties were investigated using sonic velocity ... -
Analysis of energy transfer and ternary non-covalent filler/matrix/UV stabilizer interactions in carbon nanofiber and oxidized carbon nanofiber filled poly(methyl methacrylate) composites
(Elsevier, 2011-10-27)Ternary non-covalent interactions between carbon nanofibers (CNFs), oxidized carbon nanofibers (ox- CNFs), poly(methyl methacrylate) (PMMA) chains, and benzotriazole-containing UV stabilizers were analyzed using ... -
Chemical and functional characterization of antimicrobial metabolites isolated from ascidian Rhopalaea Birkelandi
(Universidad Nacional (Costa Rica), 2011-12)Marine ecosystems have a very large diversity of resources, most of them still partially unknown, and a few others exploited for development of new industrial and toxicological products. The objective of this investigation ... -
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 ... -
An anatomical comparison between bunch and fruit of oil palm with pineapple leaf and three woods from plantations in Costa Rica
(Journal of Oil Palm Research, 2013-04)Elaeis guineensis, Ananas comusus and forest plantations are planted widely in Costa Rica; however their residues (8000 t) are not utilised. The main objective of this work was to undertake an anatomical description of the ... -
Emisiones de contaminantes atmosféricos provenientes desde fuentes fijas
(2013-08-22)Las emisiones de contaminantes atmosféricos provenientes desde fuentes fijas están reguladas por el Reglamento sobre Emisión de Contaminantes Atmosféricos provenientes de Calderas (DE-30222-S-MINAE). La normativa presente ... -
Emisiones de contaminantes atmosféricos provenientes de calderas
(2013-08-22)Las emisiones de contaminantes atmosféricos provenientes desde fuentes fijas, como son las calderas, están reguladas por el Reglamento sobre Emisión de Contaminantes Atmosféricos provenientes de Calderas (DE-30222-S-MINAE). ... -
Concentración de mercurio en el aire
(2013-08-22)El mercurio es un metal tóxico emitido a la atmósfera mediante procesos naturales y antropogénicos. Los procesos naturales incluyen: la volatilización desde medios acuáticos y vegetación, la desgasificación de materiales ... -
Scattering of light by colloidal aluminosilicate particles Produces the unusual sky-blue color of Río Celeste (Tenorio Volcano Complex, Costa Rica)
(2013-09-18)Río Celeste (Sky-Blue River) in Tenorio National Park (Costa Rica), a river that derives from the confluence and mixing of two colorless streams-Río Buenavista (Buenavista River) and Quebrada Agria (Sour Creek)-is renowned ... -
Spatial and Temporal Variation of Stable Isotopes in Precipitation across Costa Rica: An Analysis of Historic GNIP Records
(2013-11-27)The location of Costa Rica on the Central American Isthmus creates unique microclimate systems that receive moisture inputs directly from the Caribbean Sea and the Pacific Ocean. In Costa Rica, stable isotope monitoring ... -
First measurements of methyl tert-butyl ether (MTBE) in the ambient air in San Jose, Costa Rica
(2014)A great interest has arisen in establishing the impact of organic compounds on human health and air quality, especially those compounds emitted by automotive traffic. Knowledge of urban air pollutant concentrations is ... -
The manufacture and properties of oil palm and pineapple leaf fiberboard panels
(WIT Transactions on Ecology and the Environment, 2014)Particleboards were manufactured from oil palm fruit, the oil palm mesocarp fiber of Elaeis guineensis, the leaves of pineapple (Ananas comosus) and the sawdust from three fast-growing species of trees (Gmelina arborea, ... -
Physical, mechanical and hydration kinetics of particleboards manufactured with woody biomass (Cupressus lusitanica, Gmelina arborea, Tectona grandis), agricultural resources, and Tetra Pak packages
(Waste Management and Research vol.32 no.2 106-114 2014, 2014-02-11)Lignocellulosic wastes resulting from agricultural activities as well as Tetra Pak residues from urban centres can cause significant levels of pollution. A possible action to minimize this problem is to use them in the ... -
Isotope hydrology and baseflow geochemistry in natural and human-altered watersheds in the Inland Pacific Northwest, USA
(2015-02-18)This study presents a stable isotope hydrology and geochemical analysis in the inland Pacific Northwest (PNW) of the USA. Isotope ratios were used to estimate mean transit times (MTTs) in natural and human-altered watersheds ... -
Synthesis of Dihydroindolo[2,3-c]carbazole as Potential Telomerase Inhibitor
(Journal of Heterocyclic Chemistry vol.53 no.3 762-766 2015, 2015-05-27)The dictyodendrins A-E were the first marine natural products that show inhibition of telomerase. A versatile and convergent route was described for the synthesis of derivatives of these pyrrolo[2,3-c]carbazole alkaloids ... -
Key drivers controlling stable isotope variations in daily precipitation of Costa Rica: Caribbean Sea versus Eastern Pacific Ocean moisture
(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 ... -
Groundwater recharge mechanisms inferred from isoscapes in a complex tropical mountainous region
(AGU Publications, 2016-05-23)Stable isotope variations and groundwater recharge mechanisms remain poorly understood across the tropics, particularly in Central America. Here stable isotopes (δ18O and δ2H) in groundwater, surface water, and rainfall ... -
Isomerization of fatty acids: A cellular barrier mechanism in nanotechnology?
(Journal of Nanoscience and Nanotechnology Vol.17 1-9, 2017-01)This work is a kinetic study of the coupling reaction of 2-mercaptoethanol with methyl undecenoate and with methyl oleate through " click " chemistry. Reversibility and reactivity of each system were followed through Fourier ... -
Recovery of acetate by anion exchange with consecutive CO2-expanded methanol desorption: A model-based approach
(Elsevier BV, 2018-04-07)Production of bio-based acetate is commonly hindered by the high costs of the downstream processing. In this paper, a model is developed to describe a new method that recovers acetate salts using anion exchange resins, and ...
