Browsing Escuela de Química by Title
Now showing items 453-472 of 492
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Stable isotopic characterization of nitrate wet deposition in the tropical urban atmosphere of Costa Rica
(Research Square, 2021)Increasing energy consumption and food production worldwide results in anthropogenic emissions of reactive nitrogen into the atmosphere. To date, however, little information is available on tropical urban environments where ... -
Statistical Approach to Regulation of Nanotechnology: Need, Advantages and Disadvantages
(Scientific Research Publishing (China), 2020)The need to have an express regulation covering nanotechnology has been the subject of debate in the scientific literature and identified as one of the main subsets of nanotechnology field research. However, most countries ... -
Structure and Properties of Biodegradable Polymers: Rolling Effect in Poly (butylene succinate) Sheets
(SAGE Publishing (Estados Unidos), 2004)Sheets made from poly (butylene succinate) (PBS) were prepared by extrusion. They have been studied under uniaxial drawing as a function of the draw condition. Changes in molecular orientation and crystallinity were ... -
Student Camps to Promote Scientific Vocations in STEM: The Quimi Camp Case
(Universidad Nacional (Costa Rica), 2023-06-01)[Objetivo] Desde el año 1988 y hasta el año 2018, el estudiantado de secundaria en Costa Rica debía aprobar un examen final para graduarse de la escuela secundaria, y ser elegible para una educación universitaria pública. ... -
Synthesis and characterization of silver nanoparticles and their application as an antibacterial agent
(MedCrave Group (Estados Unidos), 2019)A great interest for the study of nanoscale chemical species has been studied. This review presents the main methods of chemical reduction for the preparation of silver nanoparticles, such as the preparation of silver ... -
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 ... -
The effect of solution environment and the electrostatic factor on the crystallisation of desmotropes of irbesartan
(Royal Society of Chemistry, 2019)The experimental conditions necessary for stabilising irbesartan (IBS) tautomers in solution and selectively obtaining the desmotropic crystal forms are presented herein. 1H and 2H tautomers were stabilized in specific ... -
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, ... -
Toxicity of nanoparticles: A development opportunity in environment and health
(Allied Academies (Reino Unido), 2022)Nanoparticles have a promising future for application in various fields. They provide a development opportunity for scientists and workers from different areas of being able to work with materials at the nano-scale, ... -
Tracer hydrology in a hydrometric data-limited and complex tropical mountainous region: the case of the Central American Isthmus
(European Geosciences Union, 2019)Numerous socio-economic activities are dependent on the seasonal rainfall and groundwater recharge cycle across the Central American Isthmus. Demographic growth and unregulated land use changes resulted in extensive surface ... -
Tracer-aided modelling reveals quick runo generation and groundwater losses producing young stream ow ages in a tropical rainforest catchment
(2021-05-29)There is still limited understanding of how waters mix, where waters come from and for how long they reside in tropical catchments. In this study, we used a tracer-aided model (TAM) and a gamma convolution integral model ... -
Tracing water sources and fluxes in a dynamic tropical environment from observations to modeling
(Frontiers in Earth Science, 2020-11-06)Tropical regions cover approximately 36% of the Earth’s landmass. These regions are home to 40% of the world’s population, which is projected to increase to over 50% by 2030 under a remarkable climate variability scenario ... -
Tracking the water fingerprints of Cocos Island: A stable isotope analysis of precipitation, surface water, and groundwater
(Revista de Biología Tropical, 2016)The use of stable isotopes of water, both δ2H and δ18O has provided novel insights in hydrological studies, ecological applications, understanding climate variability, and reconstructing paleoclimate. However, information ... -
Tratamiento de aguas residuales con tecnologías alternativas en una pequeña unidad doméstica–productiva
(Universidad Nacional (Costa Rica), 2013)Se evaluó el sistema de tratamiento de aguas residuales instalado en una pequeña unidad doméstica-productiva ubicada en la zona de Escazú de la provincia de San José, mediante la medición de la demanda bioquímica de ... -
Tratamiento de lodos peligrosos residuales de la empresa Prolex S.A., mediante técnicas de inmovilización
(Universidad Nacional (Costa Rica), 2009-03)En Costa Rica existen serios problemas para el tratamiento de desechos peligrosos, especialmente los lodos categorizados como inorgánicos, por contener metales tóxicos. El presente estudio establece el uso de la técnica ... -
Using Sniffer4D and SnifferV portable gas detectors for UAS monitoring of degassing at the Turrialba Volcano Costa Rica
(Advanced UAV, 2023)Since the completion of the first Sniffer UAS payload research article titled; Using UAS with Sniffer4D Payload to Document Volcanic Gas Emissions for Volcanic Surveillance: In this study the UAS system deployed carried ... -
Using UAS for monitoring the summit of the Arenal Volcano Costa Rica
(Mersin Üniversitesi (Turquía), 2023)The Arenal summit is seldom studied for several reasons. First, the eruptive activity has stopped since October 2010, second the active summit crater C is difficult to reach due to an intense steep climb through the tropical ... -
Using UAS with Sniffer4D payload to document volcanic gas emissions for volcanic surveillance
(Advanced UAV, 2022)A consistent volcanic monitoring program is crucial to the safety of the population and the efficiency of the nation. Costa Rica´s National Commission for Risk Prevention the CNE helps manage this responsibility. The ... -
Uso alternativo de excedentes agroindustriales en la formulación de fertilizantes orgánicos foliares
(Universidad Nacional (Costa Rica), 2003)Debido a la reciente demanda de alimentos a nivel mundial provocado por la explosión demográfica que ha dado en las últimas décadas, la calidad de plaguicidas y fertilizantes químicos empleados ha aumentado a un ritmo ... -
Uso alternativo de residuos de caña de azúcar obtención de espumas rígidas de poliuretano
(Universidad Nacional (Costa Rica), 2004)En este trabajo se realizó un estudio para comprobar la efectiva sustitución parcial de los reactivos de uso común en la elaboración de espumas rígidas de poliuretano, por materiales lignocelulósicos provenientes de la ...