1,720,966 research outputs found
An Accurate Inverse Model for the Detection of Leaks in Sealed Landfills
No full textLeaks from landfills to underlying soil layers are one of the main problems that endanger the sustainability of waste disposal in landfills. Indeed, the possible failing of in-situ equipment can give rise to serious pollution consequences or costly inspection work in the landfill body. In this paper, we develop the time dependent mathematical relationship between the concentration of water at the surface of the landfill and the flux at the bottom of the landfill. This makes it possible to detect a leak using non-expensive measurements made at the surface of the landfill. The resulting model is obtained by analytically solving Richard’s equation with a piecewise linear boundary condition at the bottom. The unknown coefficients of the piecewise linear functions, which can be estimated using the measurements at the surface, provide the necessary information for detecting leaks. The algorithm has been numerically tested using simulated data of rain precipitation. The method proposed could be conveniently used to complement the usual monitoring techniques due to the limited costs of its implementation
Analyzing the Efficiency of Using Different Chemical Compositions for Intensifying the Phytoextraction Processes of Mercury and Other Heavy Metals Based on Multivariate Image Tools
No full textA method is proposed and multifactorial experiments are carried out to determine the effectiveness of various compositions of chemical additives for intensifying the processes of phytoextraction of mercury and other heavy metals from soils. White creeping clover (lat. Trifolium repens L.) is used as the object of experiment. As a result of a systematic analysis of the results of experiments using the tools of multivariate visualization of large data arrays in the form of various diagrams (petal, line, bubble, and thermal), the following was established: the presence of a positive effect of monoethanolamine salt of thioacetic acid and sodium thiosulfate on phytoextraction of mercury; a pronounced positive effect of Trilon B on the phytoextraction of heavy metals, simultaneously accompanied by a destructive effect on the growth and development of plants; a positive effect on the condition of plants of phytohormone and iron chelate supplements; and the ability of oxyethylidene diphosphonic acid to protect plants from the negative effects of heavy metals
Systematical analysis of chemical methods in metal nanoparticles synthesis
No full textWe propose a short review paper on the mainly adopted techniques for the production of metal nanoparticles in industrial and laboratory scale. The methods are grouped according to the wellknown classification in bottom-up and top-down schemes, with a particular emphasis on the operating conditions specifically adopted. Namely, some aspects concerning the experimental setup, the choice of precursors and reactants and the relevant technical advantages/limitations of the methods are discussed and compared in light of the most recent issues in matter of metal nanoparticles synthesis
Production of Carbon Adsorbents from Hydrolysis Industry Waste and Methods for their Modification
No full textAbstract: Sorbents obtained from lignin, the multi-ton hydrolysis industry waste, were modified using a fullerene extract. The introduction of fullerenes into the material was performed at the mixing stage, prior to the processes of carbonization and activation. A water-alcohol solution of fullerenes was used to introduce the modifier. Based on a derivatographic analysis, it was shown that the use of fullerenes as modifiers leads to a decrease in the oxidation temperature of carbon material. Additionally, the results of X-ray studies showed a decrease in the size of carbon-graphite crystallites in the modified materials. This method of modification reduces energy consumption during the production of activated carbon, which lessens its negative impact on the environment and reduces the cost of its production. Activated carbon modified with fullerenes differs from unmodified activated carbon by an increased degree of hydrophobicity, which makes it effective in the process of purification of aqueous and highly humidified gaseous media from organic and inorganic compounds. The introduction of fullerenes increases the absorption properties of activated carbon obtained from aqueous media by 20% for methylene blue and 30% for iodine. At the same time, the porous structure of the obtained activated carbon remains practically unchanged
Predicting Emissions from the Chemical and Energy Industries: Progress in Applying Modeling Approaches
No full textA review of international experience in the development and implementation of emissions monitoring systems based on mathematical models at industrial facilities is presented. The main problems of the use of such systems are analyzed, their benefits and weaknesses are identified. It has been found that although regulatory approval of predictive emissions monitoring systems differs from country to country, there is a trend towards the widespread adoption of emission simulation technologies
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Multifractal Analysis of the Mechanical PropOKerties of the Texture of Biopolymer-Inorganic Composites of Chitosan-Silicon Dioxide
No full textAn original multifractal algorithm is proposed for calculating the fractal characteristics of the cluster texture of biopolymer-inorganic (BIN) composites from microphotographic images (MPIs) of their texture, which allows one to determine the quantitative dependence of the mechanical properties of biopolymer–inorganic composites on the characteristics of their cluster texture. As a result of the studies conducted on the MPI texture of the “chitosan-silicon dioxide” BIN composites using a multifractal algorithm, it was found that such important indicators as strength and plasticity can be quantitatively described using generalized fractal pixel dimensions of MPI samples of the BIN composite. It was established that when the amount of silicon dioxide in the samples of the BIN composite changes, the mechanical characteristics of the BIN composites, such as strength and plasticity, can be quantitatively described using generalized fractal pixel dimensions of the MPIs of the BIN composite samples
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