Browsing Química by Title
Now showing items 81-100 of 156
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Harnessing titanium dioxide surface toward novel functional materials
(2015)The ever-increasing worldwide energy consumption has led the society to quest for novel and functional materials that can be used in the development of solar fuels to some extent lessen the dependence on fossil fuels. In ... -
Heterogeneous Water Oxidation: Surface Activity versus Amorphization Activation in Cobalt Phosphate Catalysts
(2015)Is water oxidation catalyzed at the surface or within the bulk volume of solid oxide materials? This question is addressed for cobalt phosphate catalysts deposited on inert electrodes, namely crystallites of pakhomovskyite ... -
Homopropargyl alcohol 1,1-diphenylbut-3-yn-1-ol
(2018)The asymmetric unit of the title compound, C16H14O, contains one molecule with a central carbon atom having a distorted tetrahedral geometry made of a propargylic fragment, a hydroxy group and two aromatic rings. ... -
Homopropargyl alcohol 5,5-diphenylpent-2-yne-1,5-diol
(2018)In the title compound, C17H16O2, the central carbon atom has a distorted tetrahedral geometry [spread of angles = 105.71 (8)–112.75 (9)°] for its bonds to a homopropargylic but-2-yn-1-ol moiety, a hydroxy group and two ... -
Influence of bitumen and aggregate polarity on interfacial adhesion
(2017)The quality of the bitumen–aggregate interface formed in an asphalt mixture is dictated by the physicochemical properties of both materials, such as surface polarity. In order to better understand the role of polarity on ... -
Influence of nanosilica and diatomite on the physicochemical and mechanical properties of binder at unaged and oxidized conditions
(2016)Modification of binders helps address common distresses in pavements by changing their essential properties. In order to further characterize the role of additives in these changes, a set of nanosilica and diatomite modified ... -
Influence of rice field agrochemicals on the ecological status of a tropical stream
(2016-01-15)Many tropical countries contain a high density of protected ecosystems, and these may often be bordered by intensive agricultural systems. We investigated the chemical and ecological status of a stream connecting an area ... -
Light Reflection by Cuticles of Chrysina Jewel Scarabs: Optical Measurements, Morphology Characterization, and Theoretical Modeling
(2016)Cuticles of some Chrysina scarabs are characterized by flat, graded, and twisted structures of nanosized chitin fibrils. As inferred from SEM images, each species has its own spatial period or pitch P which is dependent ... -
Metals in coastal mollusks of Costa Rica
(2015-12)The input of contaminants to coastal ecosystems is a global problem on the rise. Data on metal pollution from tropical sites is often lacking and pilot surveys are urgently needed to provide a general framework to estimate ... -
Microbial Community Structure Alogn a Horizontal Oxygen Gradient in a Costa Rican Volcanic Influeced Acid Rock Drainage System
(2020-06-22)We describe the geochemistry and microbial diversity of a pristine environment that resembles an acid rock drainage (ARD) but it is actually the result of hydrothermal and volcanic influences. We designate this environment, ... -
Microwave assisted synthesis: A Mn/Ni reaction system affording Mn5Ni4, Mn2Ni2 and Mn7 complexes
(2013-11)Following our interest in microwave assisted synthesis in coordination chemistry; we report here the results of the study of a mixed metal Mn/Ni system under common bench-top conditions and using the microwave reactor. ... -
Modified Laccase-Gold Nanoparticles-Tetrathiafulvalene-SPCEs Based Biosensor to Determine W(VI) in Water
(2017)It was developed an amperometric biosensor to determine tungsten in water, based on the inhibition of laccase enzyme, by tungsten ions using pyrocathecol as a substrate. The enzyme was immobilized with a proper mixture ... -
Monomeric Germanium(II) Amides Bearing β-Diketiminato Ligands: Synthesis, Structural Characterization, and Thermal Properties
(2014-09)Germanium(II) compounds featuring β-diketiminate-type ligands are attractive for applications as nanoparticle precursors, imaging agents, and components of electronic devices. In this work, we report the synthesis of ... -
Neutral organic redox pairs based on sterically hindered hydroquinone/benzoquinone derivatives for dye-sensitized solar cells
(2018-06)Substituted derivatives of hydroquinone/benzoquinone were studied as organic redox mediators in the electrolyte for dye-sensitized solar cells (DSSCs). Thus, di-tert-butylhydroquinone (DTHQ), thymohydroquinone (ThymHQ) and ... -
Nickel-iron catalysts for electrochemical water oxidation – redox synergism investigated by in situ X-ray spectroscopy with millisecond time resolution
(2018)In future technological systems for chemical storage of renewable energy and production of non-fossil fuels, NiFe oxyhydroxides are prime candidates for efficient alkaline water oxidation (oxygen evolution reaction, OER). ...