Search results for " Petr"

The dynamics of magnetic ordering in a natural hemo-ilmenite solid solution

2007

Geophysical Journal International, 169 (3)

Incorporation of trace metals Cu, Zn, and Cd into gypsum: Implication on their mobility and fate in natural and anthropogenic environments

2020

Abstract The coexistence of calcium (Ca2+), sulfate (SO42−) with trace metal cations (M(II)) can possibly lead to M(II)-gypsum coprecipitation and solid solution formation. However, gypsum's role in the fixation of M(II) is still largely unknown. This study investigated the precipitation of Ca2+ and SO42− in the presence of M(II) (i.e., Cu2+, Zn2+, or Cd2+) and the incorporation of the metal cations into the gypsum structure at different environmental conditions. Trace metals in two natural gypsum samples (Yunnan and Neimeng, China) and one hydrometallurgical byproduct gypsum sample from a Cu refinery were also assessed. X-ray diffraction, scanning electron microscopy-energy dispersive X-ra…

Porphyroblast crystallization kinetics: the role of the nutrient production rate

2011

The mechanisms that govern porphyroblast crystallization are investigated by comparing quantitative textural data with predictions from different crystallization models. Such numerical models use kinetic formulations of the main crystallization mechanism to predict textural characteristics, such as grain size distributions. In turn, data on porphyroblast textures for natural samples are used to infer which mechanism dominated during their formation. Whereas previous models assume that the rate-limiting step for a porphyroblast producing reaction is either transport or growth, the model advanced in this study considers the production of nutrients for porphyroblasts as a potentially rate-limi…

Petro-mineralogical controls on coda attenuation in volcanic rock samples

2021

SUMMARY Seismic attenuation measurements, especially those obtained from coda decay analysis, are becoming a key data source for the characterization of the heterogeneous Earth due to their sensitivity to small-scale heterogeneities. However, the relation between the scattering attenuation measured from coda waves and physical rock properties is still unclear. The goal of this study is to identify the main petrophysical and mineralogical factors controlling coda attenuation in volcanic rocks at the laboratory scale, as a necessary step before modelling seismic waves in real volcanic media. Coda wave attenuation was estimated from ultrasonic S-wave waveforms. To quantify the heterogeneity of…

Ciprofloxacin carrier systems based on hectorite/halloysite hybrid hydrogels for potential wound healing applications

2021

The design of multifunctional nanomaterials which can help the healing processes of skin, preventing the bacterial infections, is crucial for the development of suitable therapy for the treatment of chronic lesions. The use of clay minerals in wound healing applications is well documented since the prehistoric period and offers several advantages due to their intrinsic properties. Herein, we report the development of ciprofloxacin carrier systems based on hectorite/halloysite (Ht/Hal) hybrid hydrogels for potential wound healing applications. To achieve this objective firstly the ciprofloxacin molecules were loaded onto Hal by a supramolecular and covalent approach. The so obtained fillers …

Surface emissivity retrieval from Digital Airborne Imaging Spectrometer data

2002

[1] A study has been carried out on the most recent algorithms for the estimation of land surface emissivity (e) using high-resolution data (Digital Airborne Imaging Spectrometer, DAIS) over the Rhine Valley (France) and Castilla La Mancha (Spain). Three published methods have been applied for extracting absolute spectral emissivity information from images recorded during the DAISEX experiment in 1999. They are NDVI Thresholds Method (NDVITHM), Normalized Emissivity Method (NEM) and Temperature/Emissivity Separation (TES). These lather two methods were originally designed to work over geological surfaces. Five methods have been used for extracting relative spectral emissivity. They are temp…

Effects of organic aerosol constituents on extinction and absorption coefficients and liquid water contents of fogs and clouds

1978

We have speculated on the influence of organic material on extinction and absorption coefficients and liquid water content of fogs and of clouds immediately after their condensational stage. It results therefore, that the reduction of the speed of growth from fog to cloud droplets due to the presence of organic films largely reduces the properties mentioned. Compared to that their increase coming from the surface tension reduction due to organic material being dissolved or building up films is expected to be less effective.

Integrated Geophysical Investigations at the Greek Kamarina Site (Southern Sicily, Italy)

2018

Kamarina, located in southern Sicily (Italy), was an important Greek colony since its foundation in the sixth century BC. Archaeological excavations, carried out since the twentieth century, uncovered only limited portions of the site so far. Despite the importance of the Greek colony, the presence of remarkable buildings that archaeologists expected to bring to light has not found fully correspondence in the archaeological excavations. Consequently, the integrated geophysical prospection carried out in the study area is aimed to support and address the future archaeological investigations. After the photographic and thermographic survey obtained by an unmanned aerial vehicle, we performed …

Os isotope and PGE systematics of peridotites from the Othris Opiolite, Greece

2006

"Belye lilii" : genezis finskogo mifa v bolgarii, rol' russkogo fennofil'stva, finsko-bolgarskie kontakty i posredniki s konca XIX do konca XX veka

2004

Liilia Siibergin väitöstyössä osoitetaan, miten suomalaisista on kirjallisuuden kautta Bulgariassa tullut sankareita, joita kohtaan tunnetaan erityistä sympatiaa. Samalla suomalaisista sinkoutuu pois kaikki, mikä voisi viitata epätäydellisyyteen. – Emme enää voi puhua stereotypiasta, vaan kyseessä on kansallismyytti, Siiberg toteaa. Bulgarialaisilla ei kuitenkaan ole erityisasemaa suomalaisten mielissä. Väitöskirjassa tarkastellaan Suomen ja Bulgarian välisten kulttuuri- ja kirjallisuussuhteiden syntymistä ja kehitystä sekä tutkitaan kanssakäymisen erityispiirteitä vertailevan kirjallisuustieteen ja kulttuurintutkimuksen näkökulmasta. Siibergin esittämä malli Suomen kansallismyytin syntymis…