Search results for "iron [calorimeter]"
showing 10 items of 504 documents
Vibrational spectrum of the spin crossover complex [Fe(phen)(2)(NCS)(2)] studied by IR and Raman spectroscopy, nuclear inelastic scattering and DFT c…
2006
The vibrational modes of the low-spin and high-spin isomers of the spin crossover complex [Fe(phen)(2)(NCS)(2)] (phen = 1,10-phenanthroline) have been measured by IR and Raman spectroscopy and by nuclear inelastic scattering. The vibrational frequencies and normal modes and the IR and Raman intensities have been calculated by density functional methods. The vibrational entropy difference between the two isomers, DeltaS(vib), which is--together with the electronic entropy difference DeltaS(el)--the driving force for the spin-transition, has been determined from the measured and from the calculated frequencies. The calculated difference (DeltaS(vib) = 57-70 J mol(-1) K(-1), depending on the m…
The dynamics of (57)Fe nuclei in Fe(III)-DNA condensates.
2001
Abstract The dynamics of iron nuclei in the condensates obtained by interaction of Fe III with DNA, Fe III (DNA monomer) 2 , have been investigated by variable temperature 57 Fe Mossbauer spectroscopy. Studies were effected on gel and freeze-dried samples, obtaining nearly coincident values of the parameters isomer shift and nuclear quadrupole splitting in T ranges 20–260 K. Functions ln( A T / A 77.3 ) vs. T , here employed to investigate the dynamics of Fe nuclei, showed linear trends in the T ranges 20–150 and 150–260 K, respectively, the latter with larger slopes. Data coincided for gelled and freeze-dried specimens. No variation of δ or Δ E parameters occurred at the two T intervals, w…
NHC-Based Iron Sensitizers for DSSCs
2018
International audience; Nanostructured dye-sensitized solar cells (DSSCs) are promising photovoltaic devices because of their low cost and transparency. Ruthenium polypyridine complexes have long been considered as lead sensitizers for DSSCs, allowing them to reach up to 11% conversion efficiency. However, ruthenium suffers from serious drawbacks potentially limiting its widespread applicability, mainly related to its potential toxicity and scarcity. This has motivated continuous research efforts to develop valuable alternatives from cheap earth-abundant metals, and among them, iron is particularly attractive. Making iron complexes applicable in DSSCs is highly challenging due to an ultrafa…
Controlled hydrodynamic conditions on the formation of iron oxide nanostructures synthesized by electrochemical anodization: Effect of the electrode …
2017
[EN] Iron oxide nanostructures are of particular interest because they can be used as photocatalysts in water splitting due to their advantageous properties. Electrochemical anodization is one of the best techniques to synthesize nanostructures directly on the metal substrate (direct back contact). In the present study, a novel methodology consisting of the anodization of iron under hydrodynamic conditions is carried out in order to obtain mainly hematite (alpha-Fe2O3) nanostructures to be used as photocatalysts for photoelectrochemical water splitting applications. Different rotation speeds were studied with the aim of evaluating the obtained nanostructures and determining the most attract…
Iron oxide nanostructures for photoelectrochemical applications: Effect of applied potential during Fe anodization
2019
[EN] In photoelectrochemistry, a suitable photoanode leading to high efficiencies in photocatalytic processes is a research challenge. Iron oxide nanostructures are promising materials to be used as photoanodes. In this work, different potentials during iron anodization were applied to study the properties of the synthesized nanostructures. Results revealed that nanostructures anodized at 50V presented well-defined nanotubular structures with open-tube tops, and they achieved values of photocurrent density of 0.11 mA cm(-2) at 0 rpm and 0.14 mA cm(-2) at 1000 rpm (measured at 0.50 V-Ag/Agcl), corresponding to the oxygen evolution reaction from water, i.e. 2H(2)O+4h(+)-> 4H(+)+O-2, demonstra…
Highly siderophile elements (Re, Os, Ir, Ru, Rh, Pd, Au) in impact melts from three European impact craters (Sääksjärvi, Mien, and Dellen): Clues to …
1997
Twenty-two large (10 g) impact melt samples from three Scandinavian craters (i.e., Saaksjarvi, Finland; and Mien and Dellen, Sweden) were analyzed for highly siderophile elements (HSE: platinum group elements, Rh, and Au) by the nickel sulfide technique in combination with neutron activation. The ten impact melt samples from Saaksjarvi are enriched in Ir and other highly siderophile elements (Ir = 2.48 ± 0.73 ng/g) relative to average upper crust concentrations (0.03 ± 0.02 ng/g Ir). The twelve Dellen and Mien samples are marginally enriched in Ir (0.48 ± 0.23 ng/g for Dellen, and 0.37 ± 0.23 ng/g for Mien). The amount of meteoritic component corresponds to 0.5% of a nominal CI component fo…
Layer formation on silicon steel by processing in H2/H2O at elevated temperatures
1992
Silicon steel (Fe-3wt%Si), as used for transformers and generators, has been annealed in wet hydrogen at elevated temperatures. The composition, sequence, and thicknesses of the layers found by conversion electron Mossbauer spectroscopy (CEMS) and Auger electron spectroscopy (AES) depth profiling for a 10 minutes anneal in different atmospheres are reported. In the range from 500°C to 720°C we observed carbide formation, indicating that the decarburization is hindered. Above 800°C, the layers consist of fayalite or of fayalite and iron oxides, depending on the oxygen potentialaO. At 843°C, the onset of iron oxide formation was found ataO=0.33.
Effects of legume processing on calcium, iron and zinc contents and dialysabilities
2001
Legumes are a good source of calcium, iron and zinc, but are also a source of phytates and dietary fibre components that can negatively affect the bioavailability of these minerals. To estimate the latter, an in vitro dialysis method can be applied that gives the dialysability of a mineral as an estimate of its availability for absorption. Calcium, iron and zinc contents and dialysabilities in three legumes (beans, chickpeas and lentils) and the effects of cooking treatments and industrial processing on these parameters were studied. Beans had the highest calcium content (1.54 g kg -1 dry matter (DM)) and chickpeas the lowest iron content (46.9mg kg -1 DM), whilst the zinc contents were sim…
Oral Infections and the Risk of Mortality in the Iron Age
2008
Medically unattended oral abscesses may spread to their surrounding area or even throught the entire body. Depending on the individual`s constitution, such processes may lead to a life-threatening situation or death. (Pre)historic case studies deliver more information about distribution and adverse effects of oral infections and the risk of mortality. In this particular case report an iron aged skeleton of a 35- to 45-year-old woman from Eulau (Naumburg/ Saale, Germany) shows multiple periapical lesions and their effects on the viscerocranium. Furthermore, alterations on the long bones can be associated with chronic inflammation processes.
Metallorganic routes to nanoscale iron and titanium oxide particles encapsulated in mesoporous alumina: formation, physical properties, and chemical …
2000
Iron and titanium oxide nanoparticles have been synthesized in parallel mesopores of alumina by a novel organometallic "chimie douce" approach that uses bis(toluene)iron(0) (1) and bis(toluene)titanium(0) (2) as precursors. These complexes are molecular sources of iron and titanium in a zerovalent atomic state. In the case of 1, core shell iron/iron oxide particles with a strong magnetic coupling between both components, as revealed by magnetic measurements, are formed. Mossbauer data reveal superparamagnetic particle behavior with a distinct particle size distribution that confirms the magnetic measurements. The dependence of the Mossbauer spectra on temperature and particle size is explai…