Low Temperature Measurements by Infrared Spectroscopy in CoFe2_2O4_4 Ceramic

In this paper results of new far-infrared and middle-infrared measurements (wavenumber range of 4000cm-1 - 100cm-1) in the range of the temperature from 300K to 8K of the CoFe2O4 ceramic are presented. The bands positions and their shapes are the same in the wide temperature range. The quality of the sample was investigated by X-ray, EDS and EPMA studies. The CoFe2O4 reveals the cubic structure (Fd-3m) in the temperature range from 85K to 360 K without any traces of distortion. On the current level of knowledge the polycrystalline CoFe2O4 does not exhibit phase transition in the temperature range from 8 K to 300 K.Comment: 10 pages, 6 figure

In vitro and in vivo studies on biocompatibility of carbon fibres

In the present study we focused on the in vitro and in vivo evaluation of two types of carbon fibres (CFs): hydroxyapatite modified carbon fibres and porous carbon fibres. Porous CFs used as scaffold for tissues regeneration could simultaneously serve as a support for drug delivery or biologically active agents which would stimulate the tissue growth; while addition of nanohydroxyapatite to CFs precursor can modify their biological properties (such as bioactivity) without subsequent surface modifications, making the process cost and time effective. Presented results indicated that fibre modification with HAp promoted formation of apatite on the fibre surface during incubation in simulated body fluid. The materials biocompatibility was determined by culturing human osteoblast-like cells of the line MG 63 in contact with both types of CFs. Both tested materials gave good support to adhesion and growth of bone-derived cells. Materials were implanted into the skeletal rat muscle and a comparative analysis of tissue reaction to the presence of the two types of CFs was done. Activities of marker metabolic enzymes: cytochrome c oxidase (CCO) and acid phosphatase were examined to estimate the effect of implants on the metabolic state of surrounding tissues. Presented results evidence the biocompatibility of porous CFs and activity that stimulates the growth of connective tissues. In case of CFs modified with hydroxyapatite the time of inflammatory reaction was shorter than in case of traditional CFs

XES PATTERN OF BaLaGa3O7:Nd SINGLE CRYSTALS

Analyse des spectres d'émission X de Ba, La (Lγ4, Lγ2,3) et Nd (Lγ1, Lβ2,15) et dans les régions des seuils a absorption L3 du La et L2 du Ba dans BaLaGa3O7 monocristaux avec Nd (jusqu'au 2.1 %at.) est presentée. Les résultats sont considerés par des déplacements chimiques et par des positions et intensités des satellites. It est confirmé que l'interaction de La avec de la réseau cristallin des cristaux est faible et que le niveau 4f du La participe dans l'intensité de la 5d - 2s transition. Le niveau 4f du Nd est plus loin de la bande de valence dans le cas de 2.1 %at.Investigation has been made on the Lγ4 X-ray emission line of barium and lanthanum, on the Lγ2,3 line of lanthanum, Lγ1 and Lβ2,15 lines of neodymium, as well as on the L3 emission band of lanthanum and L2 band of barium in the BaLaGa3O7 single crystals doped with Nd up to 2.1 at.% . The measurements have been performed using a single crystal spectrometer of the Johann type in the electron probe microanalysis mode. The chemica1 shifts and the satellites intensities observed for the doped crystals in comparison with the reference samples : BaF2 LaF3 and a metallic neodymium allowed us to describe the role of the 4f electrons of neodymium and of the 4f shell of lanthanum in the valence band of the crystals

Thermodynamic evaluation of biomass-to-biofuels production systems

Biomass is a renewable feedstock for producing modern energy carriers. However, the usage of biomass is accompanied by possible drawbacks, mainly due to limitation of land and water, and competition with food production. In this paper, the analysis concerns so-called second generation biofuels, like Fischer-Tropsch fuels or Substitute Natural Gas which are produced either from wood or from waste biomass. For these biofuels the most promising conversion case is the one which involves production of syngas from biomass gasification, followed by synthesis of biofuels. The thermodynamic efficiency of biofuels production is analyzed and compared using both the direct exergy analysis and the thermo-ecological cost. This analysis leads to the detection of exergy losses in various elements which forms the starting point to the improvement of conversion efficiency. The efficiency of biomass conversion to biofuels is also evaluated for the whole production chain, including biomass cultivation, transportation and conversion. The global effects of natural resources management are investigated using the thermo-ecological cost. The energy carriers' utilities such as electricity and heat are externally generated either from fossil fuels or from renewable biomass. In the former case the production of biofuels not always can be considered as a renewable energy source whereas in the latter case the production of biofuels leads always to the reduction of depletion of non-renewable resources. (C) 2013 Elsevier Ltd. All rights reserved

Evaluation of PCL and PCL/n-HAp fibres processed by melt spinning

In this work the process for the manufacture of polycaprolactone fibres containing hydroxyapatite nanoparticles by melt spinning method was developed. The effect of nanohydroxyapatite content on the fibre structure and properties was investigated with FTIR, SEM, DSC, TGA methods. The mechanical properties of obtained fibres enable further processing to scaffolds by nonwoven technologies

Reaction of winter spelt varieties on manure fertilization

W Katedrze Agronomii Uniwersytetu Przyrodniczego w Poznaniu, w latach 2007-2009 prowadzono badania nad reakcją dwóch odmian ozimych orkiszu pszennego (Schwabenpelz, Badengold) na nawożenie obornikiem (dawki obornika: 0, 15 i 30 t.ha-1). Ponadto zamierzano ustalić optymalne dawki obornika w uprawie tych odmian. Odmiany orkiszu ozimego Schwabenpelz i Badengold silnie reagowały na warunki pogodowe, szczególnie wilgotnościowe w okresie wegetacji. W korzystnym roku dla wzrostu i rozwoju roślin wydały one dwukrotnie wyższe plony niż w roku z okresowym niedoborem wody. Korzystne dla plonowania orkiszu okazało się zastosowanie 15 t obornika*ha-1. Wyższa dawka nawozu naturalnego nie tylko nie zwiększyła plonu ziarna, a często wywoływała tendencję jego spadku. Porównywane odmiany podobnie reagowały na nawożenie naturalne. Odmiana Badengold plonowała wyżej od odmiany Schwabenpelz i różnica ta wynosiła średnio 7,3t*ha-1, tj. 51%. Taka kolejność odmian wystąpiła w obu latach we wszystkich wariantach uprawowych.At Agronomy Department of Poznań University of Life Sciences in 2007-2009, experiments on reaction of two winter spelt cultivars (Schwabenpelz, Badengold) on manure fertilization (manure doses 0, 15 and 30 t*ha-1) were carried out. Moreover it was intended to find the optimal manure doses for this cultivars. Spelt cultivars Schwabenpelz and Badengold were strongly influenced by weather conditions, specially precipitation during vegetation period. In the suitable year for plants growth investigated cultivars yielded twice higher then in the year with low rainfall. It turned out that application of 15 tons of manure per hectare was advantageous for spelt. Higher rate didn't increase the yield and often caused tendency for yield decreasing. Both Schwabenpelz and Badengold cultivars reacted to natural fertilizer similarly. Badengold cv. Yielded higher then Schwabenpelz cv. and the difference reached 7.3 t*ha-1 (51%). That sequence was observed in both years and all cultivation variants