Search results for "processi"
showing 10 items of 9638 documents
Quantitative colorimetric analysis of some inorganic salts using digital photography
2011
An analytical imaging approach to the quantitation of dissolved chemical species absorbed in the visible spectral region is reported. The approach uses digital images of a series of standard solutions of the target substance and their processing with appropriate software to assign a numeric value to each standard in terms of color intensity. Such a value is directly proportional to the analyte concentration and allows the construction of a calibration graph. The results thus obtained are compared with those provided by the classical spectrophotometricmethod used to run calibration curves for colored substances. The chemical imaging technique is relative simple and affordable; in fact, it ca…
SIGNAL PROCESSING ALGORITHM FOR SCHLIEREN EFFECT CORRECTION IN FLOW ANALYSIS
2001
Due to the radial refractive index gradients that sometimes develop in flow cells during the travelling of the samples through them, the absorbance records obtained in such conditions have a strange shape, particularly at low analyte levels. To correct this phenomenon, called Schlieren effect, a simple and reliable signal processing algorithm is described in correlation to the detector characteristics of noise. The algorithm is illustrated in nitrite and nitrate determinations with proflavin from more real samples. It has a solid theoretical support and involves the subtraction from the sample records of a smoothed signal, acquired by working with a blank solution.
A Paradigm Interpreting the City and the Analytic Network Process for the Management of Urban Transformations
2018
When urban and environmental transformations occur in areas where the equilibrium between nature and culture is complex and fragile, public ad-ministrations could decide to induce private investments using several tools, such as financial contributions to those projects of refurbishment that better re-spect the purpose of improving the environmental quality and of preserving the local architecture. Multicriteria models may support public decision process re-garding this issue, but it is essential to adopt a scientific paradigm that provides a major theoretical reference. This study proposes the development of a net-work model based on the scientific paradigm by Rizzo and the Analytic Net-wo…
Studiju programmās studentu saņemto atzīmju analīzes metodika un programmatūra
2021
Bakalaura darbs „Studiju programmās studentu saņemto atzīmju analīzes metodika un programmatūra” tika izstrādāts ar mērķi izveidot programmatūru un analizēt Latvijas Universitātes studiju programmas, apskatot studentu iegūtās atzīmes mācību priekšmetos. Bakalaura darba tēmas aizsācēji ir Kārlis Podnieks un Pēteris Ručevskis ar pētījumu „Kā Datorikas fakultātes pasniedzēji liek atzīmes: divi klasteri”, kas tika prezentēts Latvijas Universitātes 75.zinātniskajā konferencē. Bakalaura darba mērķis bija izstrādāt programmatūru, kas ļautu efektīvi apstrādāt studiju datus. Iegūtos datus izmantot eksperimentiem, lai apskatītu studiju programmas un to kursos studentu nopelnīto atzīmju sakarības. Izs…
Ancestral Reconstruction and Investigations of Genomic Recombination on some Pentapetalae Chloroplasts
2019
Abstract In this article, we propose a semi-automated method to rebuild genome ancestors of chloroplasts by taking into account gene duplication. Two methods have been used in order to achieve this work: a naked eye investigation using homemade scripts, whose results are considered as a basis of knowledge, and a dynamic programming based approach similar to Needleman-Wunsch. The latter fundamentally uses the Gestalt pattern matching method of sequence matcher to evaluate the occurrences probability of each gene in the last common ancestor of two given genomes. The two approaches have been applied on chloroplastic genomes from Apiales, Asterales, and Fabids orders, the latter belonging to Pe…
A study of the effect of molecular and aerosol conditions in the atmosphere on air fluorescence measurements at the Pierre Auger Observatory
2010
The air fluorescence detector of the Pierre Auger Observatory is designed to perforin calorimetric measurements of extensive air showers created by Cosmic rays of above 10(18) eV. To correct these measurements for the effects introduced by atmospheric fluctuations, the Observatory contains a group Of monitoring instruments to record atmospheric conditions across the detector site, ail area exceeding 3000 km(2). The atmospheric data are used extensively in the reconstruction of air showers, and are particularly important for the correct determination of shower energies and the depths of shower maxima. This paper contains a summary of the molecular and aerosol conditions measured at the Pierr…
Recovery of Lithium Carbonate from Dilute Li-Rich Brine via Homogenous and Heterogeneous Precipitation
2022
An extensive experimental campaign on Li recovery from relatively dilute LiCl solutions (i.e., Li+ similar to 4000 ppm) is presented to identify the best operating conditions for a Li2CO3 crystallization unit. Lithium is currently mainly produced via solar evaporation, purification, and precipitation from highly concentrated Li brines located in a few world areas. The process requires large surfaces and long times (18-24 months) to concentrate Li` up to 20,000 ppm. The present work investigates two separation routes to extract Li+ from synthetic solutions, mimicking those obtained from low-content Li+ sources through selective Li+ separation and further concentration steps: (i) addition of …
Watching adsorption and electron beam induced decomposition on the model system Mo(CO)(6)/Cu(111) by X-ray absorption and photoemission spectroscopies
2013
Abstract An in-depth study of the first steps of electron beam assisted growth of Mo from molybdenum hexacarbonyl on Cu(1 1 1) has been carried out exploiting the complementarity of X-ray photoemission and X-ray absorption spectroscopies. Frank van der Merwe (2D) growth mode has been observed for the completion of the two first monolayers of adsorbed molecules through a simple physisorption process. Irradiation of the Mo(CO)6 deposit by 1 keV electron beam induces a modification of molybdenum coordination, the average number of C-neighbors decreasing from 6 to 3. Decomposed molecules remain on the surface after annealing at 520 K and organize themselves, the molybdenum atoms moving in Cu(1 …
Is the selective information processing of food and body words specific to patients with eating disorders?
1993
The selective processing of food- and body size-related information was investigated using a modified version of the Stroop task. Anorexic and bulimic patients and matched female controls were compared on the basis of categorical (diagnosis), dimensional (restraint and drive for thinness) criteria, or both. The findings suggest that the phenomenon assessed by the Stroop paradigm is not exclusive to patients with a clinical eating disorder, but patients and those control subjects who are restrained eaters with a high drive for thinness share a selective processing of information related to shape and eating. The discussion focuses on the implications of these findings. © 1993 by lohn Wiley & …
An environment based approach for the ant colony convergence
2020
Abstract Ant colony optimization (ACO) algorithms are a bio inspired solutions which have been very successful in combinatorial problem solving, also known as NP-hard problems, including transportation system optimization. As opposed to exact methods, which could give the best results of a tested problem, this meta-heuristics is based on the stochastic logic but not on theoretical mathematics demonstration (or only on certain well defined applications). According to this, the weak point of this meta-heuristics is his convergence, its termination condition. We can finds many different termination criteria in the scientific literature, yet most of them are costly in resources and unsuitable f…