Search results for "engineering.material"
showing 10 items of 2352 documents
In-situ Mössbauer Spectroscopy with MIMOS II at Rio Tinto, Spain
2010
The Rio Tinto, located in southwest Spain, exhibits a nearly constant, acidic pHvalue along its course. Due to the formation of sulfate minerals, Rio Tinto is considered a potential analogue site for sulfate-rich regions on Mars, in particular at the landing site of the Mars Exploration Rover Opportunity, where the ferric sulfate mineral jarosite was identified with Opportunity's Mössbauer spectrometer. Primary and secondary mineralogy was investigated in situ with portable Raman and Mössbauer spectrometers at four different Rio Tinto sampling sites. The two techniques analyse different sample portions due to their specific field of view and sampling depth and provide complementar…
Pressure and Temperature Effects on Low-Density Mg3Ca(CO3)4 Huntite Carbonate
2019
Pressure (P)–volume (V)–temperature (T) relations of huntite [Mg3Ca(CO3)4] have been determined in situ up to 5 GPa and 500 °C using a resistive-heated diamond-anvil cell and synchrotron X-ray diff...
Designing solid optical sensors for in situ passive discrimination of volatile amines based on a new one-step hydrophilic PDMS preparation
2016
Abstract We reported an optimal material for embedding chemoresponsive dyes based on modified commercial PDMS. A new approach to impart hydrophilicity to H-PDMS in an unique step was developed by addition of tetraethyl orthosilicate (TEOS) and in absence of basic or acid aqueous mixtures or hydroxyl-compounds during the PDMS coating process. This incorporation significantly enhances the performance of PDMS-based devices for sensing applications. New colorimetric sensors for passive detection and in situ discrimination of volatile amines have been obtained. The limit of detection achieved was 1.5 mg m −3 for both, dimethylamine and methylamine, suitable to control real working atmospheres. T…
Mafic alkaline metasomatism in the lithosphere underneath East Serbia: evidence from the study of xenoliths and the host alkali basalts
2010
Effects of mafic alkaline metasomatism have been investigated by a combined study of the East Serbian mantle xenoliths and their host alkaline rocks. Fertile xenoliths and tiny mineral assemblages found in depleted xenoliths have been investigated. Fertile lithologies are represented by clinopyroxene (cpx)-rich lherzolite and spinel (sp)-rich olivine websterite containing Ti-Alrich Cr-augite, Fe-rich olivine, Fe-Al-rich orthopyroxene and Al-rich spinel. Depleted xenoliths, which are the predominant lithology in the suite of East Serbian xenoliths, are harzburgite, cpxpoor lherzolite and rare Mg-rich dunite. They contain small-scale assemblages occurring as pocket-like, symplectitic or irreg…
Effect of a novel physical pretreatment process on the drying kinetics of seedless grapes
2000
In this paper an alternative physical method for enhancing the drying rate of seedless grapes is proposed. It consists of the superficial abrasion of the grape peel using an inert abrasive material. The effectiveness of this novel process was compared to that of the traditional ethyl oleate dipping process by analysing not only their respective drying times, but also the peel surfaces by scanning electron microscopy. Moreover, the drying kinetics of the above two treatments was reconstructed by using a mathematical model in which the grape pretreatment used was assumed to affect the water diffusivity in the grape peel, but not in the grape pulp. Even though the abrasion method was found to …
Biofiltration System for Purification of Composting Waste Gases
2006
The biofiltration technique for the purification of polluted air from composting facility volatile compounds was studied. Two different biowaste composting techniques were compared with regard to emission of NH3 and H2S. The ammonia removal was observed in aerobic phase of active composting period, respectively H2S in anaerobic phase. Biofiltration process was realized in modified solid- state fermentation system (SSF). The biodegradation of volatile compounds was investigated in one and two stage systems with inert packing material and hemoautotrofic microorganisms designed DN-1 (Pseudomonas sp.), DN-2 (Nitrisomonas sp.), DN-3 (Nitrobacter sp.) and DN-13 (Sarcina sp.) and Thiopharus-3. The…
Effect of fillers on the properties of recycled polymers
2003
The main problems in post-consumer plastics recycling are due to the degradation undergone during lifetime and during processing steps. Moreover, for heterogeneous recycling, the incompatibility among the different polymeric phases give rise to secondary materials with low mechanical and thermomechanical properties. The properties-reprocessing relationships are an important tool for determining not only the properties of the recycled polymers but also the strategies to apply (processing conditions, stabilisers, fillers, compatibilizers, etc) in order to obtain recycled polymers with good mechanical properties. In this work the effect of adding inert fillers and modifier agents to recycled p…
Refractive index of the CuAlO2delafossite
2008
The refractive index of the CuAlO2 delafossite has been determined from interference measurements in single crystals performed in the visible, near and mid infrared regions of the spectrum. The analysis of the refractive index dispersion corresponding to light polarization perpendicular to the c-axis (P ⊥ c) yields a static dielectric constant of 0 = 7.7 ± 0.8 and a low frequency electronic constant ∞ = 5.1 ± 0.1. The relevant infrared active mode is found to be at 550 ± 25 cm−1. The electronic contribution can be well described by a Penn gap at 39 000 ± 1000 cm−1. Both the refractive index and its dispersion are found to be smaller for P||c than for P ⊥ c.
Raman and infrared spectromicroscopy of manganese oxides
2009
Abstract Confocal micro-Raman and micro-FT-IR spectroscopies have been used to probe the phase composition of nominally pure single-crystal MnO and mixed MnO–Mn 3 O 4 samples, grown by the method of chemical transport reactions on MgO(1 0 0) substrate. The presence of spinel Mn 3 O 4 phase has been clearly detected in both samples by Raman and FT-IR spectroscopies. The size of the spinel Mn 3 O 4 phase regions has been estimated to be below 20 μm.
Quaternary Heusler Compounds without Inversion Symmetry: CoFe 1+ x Ti 1– x Al and CoMn 1+ x V 1– x Al
2011
We report the quaternary Heusler compound derivatives CoFe1+xTi1–xAl and CoMn1+xV1–xAl, which do not have centers of inversion. Classical T2T′M (T, T′ = transition metal, M = main group element) Heusler compounds (prototype: Cu2MnAl) crystallize in the L21 structure, space group Fmm (225) that exhibits a center of inversion. Replacing one of the T2 atoms by another transition element (T″) results in a quaternary TT′T″M compound with F3m symmetry (Y; structure type LiMgPdSn) without center of inversion. In the case of “quasi closed shell” compounds with 24 valence electrons in the primitive cell, one expects the absence of ferromagnetism according to the Slater–Pauling rule. Increasing the n…