Search results for "35"

Sedimentary humic substances from lakes in Latvia

1997

Humic and fulvic acids, isolated from sediments of lakes in different trophic states (Latvia) were studied. The humic substances (HS) were characterized by their elemental and functional composition, their spectral properties, and molecular mass. The humus properties strongly depend on the origin of the sedimentary HS. Substantial similarity between sedimentary HS from oligotrophic and dystrophic water bodies was found, unless the biology of these lakes greatly differs. Humic molecules from sediments of oligotrophic and dystrophic lakes are smaller, more uniform, and contain lower amounts of carboxyl- and hydroxyl-groups than HS from meso- and eutrophic water bodies. On the other hand, sedi…

Thermal energy storage in granular deposits

2017

Energy storage technology is crucial for the development of the use of renewable energy sources. This is a substantial constraint, however it can, to some extent, be solved by storing energy in its various forms: electrical, mechanical, chemical and thermal. This article presents the results of research in thermal properties of granular deposits. Correlation between temperature changes in the stores over a period of time and their physical properties has been studied. The results of the research have practical application in designing thermal stores based on bulk materials and ground deposits. Furthermore, the research results are significant for regeneration of the lower ground sources for…

Establishing material hygrothermal characteristics via long-term monitoring and best-fit numerical models

2020

Numerical models of heat and moisture transfer for performance forecast of lightweight insulating assemblies require many inputs. These include exterior climate data (i.e. temperature, relative humidity, solar radiation), interior climate data or standard models, transfer coefficients, correct initial conditions, etc. Most importantly, one needs reliable material models. A material model includes porosity, density, heat capacity, but also non-constant properties, such as thermal conductivity, vapor/liquid water diffusivity, sorption curves. These are, in general, difficult to determine, and material database entries often are incomplete, or simply non-existent. However, if one performs long…

Screening of halogenated aromatic compounds in some raw material lots for an aluminium recycling plant

2004

Four samples of scrap raw materials for an aluminium recycling plant were screened for the occurrence of persistent halogenated aromatic compounds. The samples contained waste from handling of electric and electronic plastics, filter dust from electronic crusher, cyclone dust from electronic crusher and light fluff from car shredder. In our screening analyses, brominated flame retardants were observed in all samples. Polybrominated diphenyl ethers (PBDE) were identified in all samples in amounts of 245–67450 ng/g. The major PBDE congeners found were decabromo- and pentabromodiphenyl ethers. 1,1-bis(2,4,6-tribromophenoxy)ethane, hexabromobenzene, ethyl-pentabromobenzene, tetrabromobisphenol-…

LFER and the Effect of Temperature on Oxyanion Adsorption by Goethite

2019

A linear relationship between the Gibbs free energy, ΔGr,H+, of the aqueous complex deprotonation reaction, and the Gibbs free energy, ΔGr,ads, of bidentate surface complexation reaction of oxyanions was derived from modelling of temperature dependent batch equilibrium adsorption experiments. As exemplified in this study, this relationship may be exploited to predict temperature-dependent adsorption behavior of oxyanions not yet known such as pertechnetate.

Una propuesta de tipificación de las regiones no urbanas en la Unión Europea

2016

Este trabajo presenta el proceso metodológico conducente a la elaboración de tipologías de desarrollo regional elaboradas en el marco del proyecto EDORA3 (European Development Opportunities for Rural Areas). Constituyen un importante punto de referencia en el proceso de actualización de los estereotipos que subyacen en el diseño e implementación de la política de desarrollo regional, y pueden convertirse en un instrumento de apoyo a la toma de decisiones mejor adaptado a la realidad regional europea.

Premio “Ecosistemas” al mejor resumen de Tesis Doctoral publicado en 2013

2014

Pyriproxyfen, a juvenoid hormone analog, does not induce male production in parthenogenetic lineages of Eucypris virens (Crustacea: Ostracoda)

2007

Analogs of juvenoid hormones are increasingly recommended for controlling insect pests in agriculture. One of these analogs, pyriproxyfen, was found to be very potent in inducing male production in Daphnia under laboratory conditions, even after acute exposure. Other studies also demonstrated a major role of juvenoid hormones for the sex determination in arthropods that have sex chromosomes. We exposed parthenogenetic lineages of the freshwater ostracod Eucypris virens to a wide range of pyriproxyfen concentrations, and compared mortality and fecundity between treated and control animals. Animals exposed to the highest concentrations of pyriproxyfen (3-30 nM) experienced a higher mortality …

THE POSSIBILITY OF DISPOSING OF SPENT COFFEE GROUND WITH ENERGY RECYCLING

2015

The current policy of waste management requires, above all, a gradual reduction of waste amount and, to a larger extent, forces us to seek new methods of waste disposal. Recycling the energy contained in biomass waste is a more and more universally applied method of thermal converting. Biomass combustion allows saving fossil fuels which fits into sustainable development. This paper checks the possibility of using spent coffee ground (SCG) in energy recycling using a combustion process. This particular biomass type up to now has not been widely examined, which inclines to consider its usage as a potential additive to alternative fuels. In the study, we examined the quality of fuel, which was…

Internal heat gain from different light sources in the building lighting systems

2017

EU directives and the Construction Law have for some time required investors to report the energy consumption of buildings, and this has indeed caused low energy consumption buildings to proliferate. Of particular interest, internal heat gains from installed lighting affect the final energy consumption for heating of both public and residential buildings. This article presents the results of analyses of the electricity consumption and the luminous flux and the heat flux emitted by different types of light sources used in buildings. Incandescent light, halogen, compact fluorescent bulbs, and LED bulbs from various manufacturers were individually placed in a closed and isolated chamber, and t…