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Wyszukujesz frazę "Gutiérrez, L." wg kryterium: Autor


Wyświetlanie 1-8 z 8
Tytuł:
Role of calcium and magnesium cations in the interactions between kaolinite and chalcopyrite in seawater
Autorzy:
Uribe, L.
Gutierrez, L.
Laskowski, J. S.
Castro, S.
Powiązania:
https://bibliotekanauki.pl/articles/109955.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
froth flotation
chalcopyrite
chalcopyrite flotation
clay minerals
kaolinite
seawater
slime coating
Opis:
A number of flotation plants around the world have increased the use of seawater due to limited sources of fresh water. The aim of this research work is to study the role that Mg2+ and Ca2+ ions play in the interactions between kaolinite and chalcopyrite in seawater. In order to achieve this objective, the effect of kaolinite on flotation of chalcopyrite is studied over the pH range from 8 to 11, when flotation is carried out in seawater and in a 0.01M NaCl solution. The influence of calcium, magnesium, sodium, and potassium ions on the extent of depression by kaolinite is evaluated. The micro-flotation results indicate that chalcopyrite is depressed by kaolinite in both 0.01 NaCl solution and seawater. In the 0.01 NaCl solution, the depressing effect of kaolinite decreases as the pH increases from 8 to 11. However, the results obtained using seawater show that the depressing effect of kaolinite is similar to what is observed in a 0.01 NaCl solution only at pH values below 9, but above this pH kaolinite significantly affects the recovery of chalcopyrite. The results from experiments with using solutions containing individual cations show that the depressing action of kaolinite in the presence of Mg2+ and Ca2+ is more obvious at pH values of 9 and 10, respectively, which correlates with the pH values at which the first hydroxy-complexes of these divalent cations start forming. This seems to indicate that depressing effect of kaolinite on chalcopyrite in seawater may be related to formation of hydrolyzed species of calcium and magnesium. These species can induce heterocoagulation between kaolinite and chalcopyrite. The trends observed in the micro-flotation experiments are in good agreement with the results of the induction time measurements and slime coating tests.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 2; 737-749
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anderson Localization Phenomenon in One-Dimensional Elastic Systems
Autorzy:
Méndez-Sánchez, R.
Gutiérrez, L.
Morales, A.
Flores, J.
Díaz-de-Anda, A.
Monsivais, G.
Powiązania:
https://bibliotekanauki.pl/articles/1399046.pdf
Data publikacji:
2013-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.15.Rn
71.23.An
05.45.Mt
05.60.Gg
Opis:
The phenomenon of the Anderson localization of waves in elastic systems is studied. We analyze this phenomenon in two different sets of systems: disordered linear chains of harmonic oscillators and disordered rods which oscillate with torsional waves. The first set is analyzed numerically whereas the second one is studied both experimentally and theoretically. In particular, we discuss the localization properties of the waves as a function of the frequency. In doing that we have used the inverse participation ratio, which is related to the localization length. We find that the normal modes localize exponentially according to the Anderson theory. In the elastic systems, the localization length decreases with frequency. This behavior is in contrast with what happens in analogous quantum mechanical systems, for which the localization length grows with energy. This difference is explained by means of the properties of the reflection coefficient of a single scatterer in each case.
Źródło:
Acta Physica Polonica A; 2013, 124, 6; 1063-1068
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two significant experiences related to radon in a high risk area in Spain
Autorzy:
Sainz, C.
Gutierrez-Villanueva, J. -L.
Fuente, I.
Quindos, L.
Soto, J.
Arteche, J. -L.
Quindos Poncela, L. S.
Powiązania:
https://bibliotekanauki.pl/articles/148910.pdf
Data publikacji:
2010
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
radon
workplace
mitigation
pilot house
Opis:
Radon is a natural radioactive gas and it is currently accepted as being responsible for lung cancer in some cases. One of the most important sources of indoor radon is from the soil. The radium content of soil is also a very important factor to be taken into account. The natural radiation map of Spain (MARNA) classifies the country into three regions with different levels of natural gamma radiation. There are some areas in Spain with high levels of natural radiation one of those is the province of Salamanca. Western part of this province presents a population of 20 000 inhabitants and 7% of the houses have an indoor radon concentration above 400 Bqźm–3. In this high risk area, the village of Villar de la Yegua is of special interest: 11% of the houses in this village have an indoor radon level below 400 Bqźm–3, 89 per cent have above 400 Bqźm–3 and 71 per cent of the houses have a radon concentration above 1000 Bqźm–3. An old uranium mine site close to this village has been selected for the construction of an experimental pilot house. It is a two story house located in the place with a very high 226Ra concentration in soil. Radon in soil at 1 m depth has an average level of 250 kBqźm–3. We present in this work the characteristics of the experimental unit located in this high risk area and we describe the zone where one of the Spanish villages with the highest radon concentration is located. This is a very interesting place for further research on indoor radon concentration and it is a unique opportunity of testing radon monitors, radon passive detectors and remedial actions for the mitigation of radon in real conditions. It is common to carry out intercomparison exercises under laboratory conditions. Nonetheless, it is not so common to develop these exercises in real conditions as we have in the experimental unit we present here. We offer in this work the possibility for other research groups of testing their equipments in this unit and we also show the evolution of the works carried out in the locality of Villar de la Yegua.
Źródło:
Nukleonika; 2010, 55, 4; 513-518
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microdamage distribution in fatigue fractures of bone allografts following gamma-ray exposure
Autorzy:
Presbítero, G.
Hernandez-Rodríguez, M. A. L.
Contreras-Hernandez, G. R.
Vilchez, J. F.
Susarrey, O.
Gutiérrez, D.
Powiązania:
https://bibliotekanauki.pl/articles/307297.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
rozkład Weibulla
pękanie zmęczeniowe
promieniowanie gamma
kość korowa
mikrouszkodzenia
allografts
Weibull distribution
fatigue fracture
gamma radiation
cortical bone
microdamage
Opis:
Although clear evidence of significant differences in bone properties have been extensively studied, results vary under the ranges usually used for sterilization purposes (25-35 kGy). Hence, the aim of this work was the study of the mechanical properties and microdamage development of human bones used as allografts following gamma-ray exposure, followed by an extensive statistical analysis of microdamage effects in fatigue behaviour. Methods: Specimens of the cortical region of human femurs were exposed to 15-25 kGy and 26-30 kGy radiation levels, then they were subjected to compression fatigue tests until fracture. The fatigue life was determined in relation to the radiation level, and the evolution of microdamage was assessed through fluorescence microscopy in order to calculate characteristic lengths of microcracks. Results: Significant differences in fatigue life were detected (p < 0.05) between non-radiated (control) and radiated specimens, resulting in a drastic 89.2% fatigue life reduction of the 15-25 kGy group, and 95.3% in the 26-30 kGy group in comparison to the control. Microdamage analysis showed a considerable increase in microcrack lengths when bone was exposed to gamma radiation, which may indicate that bones used as allografts could fracture at some point when subjected to in vivo loading conditions. Conclusions: The results of our research indicate that, even if a range of 15-25 kGy is suggested to sterilize bone allografts, such practice needs to be reconsidered. In addition, with use of Weibull distribution, this work describes the conditions in which microcracks grow towards the fracture of bones in relation to the decrease in their mechanical properties.
Źródło:
Acta of Bioengineering and Biomechanics; 2017, 19, 4; 43-53
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A fatal case of canine cutaneous leishmaniosis in a dog
Autorzy:
Ortega-Pacheco, A.
Gutierrez-Blanco, E.
Escamilla- Flores, W.
Cordero-Guillermo, L.
Jimenez-Coello, M.
Loria-Cervera, N.
Powiązania:
https://bibliotekanauki.pl/articles/6731.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Parazytologiczne
Źródło:
Annals of Parasitology; 2019, 65, 2
0043-5163
Pojawia się w:
Annals of Parasitology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Laboratory of Natural Radiation (LNR) : a place to test radon instruments under variable conditions of radon concentration and climatic variables
Autorzy:
Quindós Poncela, L. S.
Sainz Fernández, C.
Gutiérrez-Villanueva, J.-L.
Fuente Merino, I.
Celaya González, C.
Quindós López, L.
Quindós López, J.
Fernández Lopez, E.
Fernández Villar, A.
Powiązania:
https://bibliotekanauki.pl/articles/147764.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
active monitors
interlaboratory comparison
in-situ
radon
Opis:
The publication of the new European Union Basic Safety Standards represents a remarkable milestone in the fi eld of radiological protection in terms of adding radon exposure to this framework. Therefore, the coming years will bring the need to measure radon not only in the workplaces but also in the living spaces as a direct outcome of the application of the new EU Directive. So, the importance of having reliable instruments is evident and interlaboratory exercises are becoming more and more popular. However, most of them are carried out under constant conditions of meteorological variables. We present in this paper a facility to broaden the interlaboratory comparisons further by adding the study of radon exposures under real conditions of changes in climatic parameters. In addition, the facility has the possibility to verify the response of radon monitors when the radon concentration changes several orders of magnitude in a short period of time. Our work shows some results of one of the interlaboratory exercises carried out in the premises, where the radon levels were rather homogeneous in the testing room.
Źródło:
Nukleonika; 2016, 61, 3; 275-280
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fractal morphology of Beta vulgaris L. cell suspension culture permeabilized with Triton X-100
Autorzy:
Arenas-Ocampo, M.
Alamilla-Beltran, L.
Vanegas-Espinoza, P.E.
Camacho-Diaz, B.H.
Campos-Mendiola, R.
Gutierrez-Lopez, G.
Jimenez-Aparicio, A.
Powiązania:
https://bibliotekanauki.pl/articles/25018.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
morphology
Beta vulgaris
cell suspension culture
Triton X-100
morphometry
cell culture
chemical agent
Opis:
n this work, morphology of Beta vulgaris L. cells permeabilized with 0.7 mM of Triton X-100® was evaluated using digital image processing and concepts of fractal dimension (perimeter- area relations). Important morphometric changes were found when the contact-time with chemical agent was increased.The size of cells decreased, the cells lost the roundness and their shape was more sinuous; this behaviour was a result of a probable shrinkage caused by the excess of exposure with the permeabili- zation agent. Morphology of B. vulgaris cells after permeabili- zation, exhibited a fractal nature since the slope of the ratio of the logarithm of the perimeter vs logarithm of the area was higher than unit. Fractal geometry of the cell morphology was affected as a re- sult of the exposure to Triton X-100®. Those changes can be attri- buted to the loss of turgor and structure of the cell wall.
Źródło:
International Agrophysics; 2012, 26, 1
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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