337 research outputs found
Multi-use of the white mulberry (Morus alba L.)
In 2006 Institute of Natural Fibres and Medicinal Plants (INF&MP) began research on an old Polish cultivar of white mulberry - “Żółwińska”. By that time in Europe the white mulberry had been forgotten or known only as a plant associated with breeding of mulberry silkworms. Nevertheless, the initial studies have shown great potential of this plant in energy, food and pharmaceutical industries. The leaves and fruits contain very valuable active substances, which may be used in health care. What is more, very fast growth of mulberry causes that biomass of the plant may be used as biofuel. The aim of the article is promoting the white mulberry and presenting its possible various uses, which may be very useful for several sectors of the European economy
Application of mechanical activation in synthesizing multiferroic Pb(Fe1/2Nb1/2)O3 powders
In the study, the method of high-energy powder milling – mechanical activation (MA) was used for synthesizing
Pb(Fe1/2Nb1/2)O3 (PFN) powders. For the purpose of comparing the influence of high-energy milling on PFN synthesis, two groups of powder samples were used. The first mixture consisting of simple oxide powders; the second one consisting of compound oxide powders. The obtained powders were subjected to structural analysis with the use of XRD and Mossbauer spectroscopy. Tests revealed that during the process of high-energy milling of initial constituents a partial synthesis of PFN material phases occurs. By comparing the two methods of PFN synthesizing it may be stated that mechanical activation in the case of a simple oxide mixture (PFN1) is equally effective as for a compound oxide mixture (PFN2).[1] Y. X u, Ferroelectric materials and their applications. North – Holland, Amsterdam 1991.
[2] S.L. S w a r t z, V.E. W o o d, Condensed Matter News 1, 4-14 (1992)[3] E.G. F e s e n k o, A.Ya. D a n c i g e r, O.N. R a z u -m o v s k a y a, Novye piezokeramicheskie materialy, RGU, Rostov-na-Donu, 1983.
[4] O. R a y m o n d, R. F o n t, N. S u a r e z, J. P o r -t a l l e s, J. M. S i q u e i r o s, Ferroelectrics 294, 141
(2003).
[5] K. S i n g h, S.A. B a n d, W.K. K i n g e, Ferroelectrics 306, 179 (2004).
[6] X. G a o, J. X u e, J. W a n g, Journal of the American Ceramic Society 85, 565 (2002).
[7] D. B o c h e n e k, Z. S u r o w i a k, Journal of Alloys and Compounds 480, 732-736 (2009).
[8] D. B o c h e n e k, J. D u d e k, The European Physical Journal – Special Topics 154, 1 19-22 (2008).
[9] D. B o c h e n e k, R. Z a c h a r i a s z, Archives of Metallurgy and Materials, 54, 903-910 (2009).
[10] D. B o c h e n e k, Journal of Alloys and Compounds 504, 508-513 (2010).
[11] B.D. S t o j a n o v i c, A.Z. S i m o e s, C.O. P a i -v a - S a n t o s, C. J o v a l e k i c, V.V. M i t i c, J.A.
V a r e l a, Journal of the European Ceramic Society 25, 1985-1989 (2005). [12] J.S. B e n j a m i n, Scientific American 234, 40-43 (1976).
[13] A.S. K h i m, X. J u n m i n, J. W a n g, Journal of Alloys and Compounds 343, 156-163 (2002).
[14] X.S. G a o, J.M. X u e, T. Y u, Z.X. S h e n, J. W a n g, Materials Chemistry and Physics 75, 211-215 (2002).
[15] J. W a n g, D.M. W a n, J.M. X u e, W.B. N g, Singapore Patent 9801566-2, 1998.
[16] J. W a n g, D.M. W a n, J.M. X u e, W.B. N g, Journal of the American Ceramic Society 82, 477 (1999).
[17] D. D e r c z, J. D e r c z, K. P r u s i k, A. H a n c, L. P a j ą k, J. I l c z u k, Archives of Metallurgy and
Materials, 54, 741-745 (2009).
[18] L.B. K o n g, J. M a, H.T. H u a n g, W. Z h u, O.K. T a n, Materials Letters 50, 129-133 (2001).
[19] D. B o c h e n e k, Z. S u r o w i a k, J. K r o k - K o w a l -s k i, J. P o l t i e r o v a - V e j p r a v o v a, Journal of Electroceramics 25, 122-129 (2010).
[20] Y. Y a n g, H.B. H u a n g, J.-M. L i u, Z.G. L i u, Ferroelectrics 280, 75-82 (2002)
Structure and magnetic properties of nanocrystalline Fe-Mo alloys prepared by mechanosynthesis
Nanocrystalline samples of Fe8 0 Mo 20 and Fe50 Mo 50 alloys were prepared by the mechanical milling method. The structure, lattice parameters, and crystallite size were determined by the X -ray diffraction . The magnetic properties of the milled products were determined by the M ossbauer spectroscopy .
It was observed that in the case of the Fe80 Mo 20 alloy a solid solutio n of Mo in Fe was formed with the lattice parameters of Fe increasing from 0.28659 nm to 0.29240 nm and the crystalli te size decreasing from 250 nm to 20 nm. In the case of the Fe50 Mo 50 alloy there were no clear changes in values of the lattice parameters of Fe and Mo during the millin g pro cess, but the crystallite size decreased from 200 nm to 15 nm. M ossbauer spectra revealed different magnetic phases in the mechanosynthesized Fe-Mo samples. In the case of the Fe80 Mo 20 alloy , the spectrum for the milled mi xture indicated the formation of a solid solution. In contrast, for the Fe50 Mo50 the spectrum indicated the disappeara ce of the ferromagnetic phase
Strukture and Mossbauer spectroscopy studies of multiferroic mechanically activated aurivillius compounds
X-ray di raction and 57Fe Mössbauer spectroscopy were applied as complementary methods to investigate the
structure and hyper ne interactions of the Aurivillius compounds prepared by mechanical activation and subsequent
heat treatment. Preliminary milling of precursors enhanced the di usion process and pure Aurivillius compounds
were obtained at lower temperature as compared with conventional solid-state sintering technology (lower at least
by 50 K). All the investigated Aurivillius compounds are paramagnetic materials at room temperature
Search for canted spin arrangement in with Mössbauer spectroscopy
The materials studied were polycrystalline compounds E (x = 0.1, 0.2, 0.3, 0.4) which crystallize in a tetragonal lattice and display a variety of spin arrangements. The compounds have been measured with Mössbauer spectroscopy over the temperature range 80–320 K in order to investigate the spin reorientation processes. Each compound was studied in a wide temperature range, with precise Mössbauer scanning in the vicinity of the transition. The set of spectra obtained for a given compound was analyzed using simultaneous fi tting procedure to investigate the infl uence of the transition on the shape of the spectra. The fitting program was specifi ed to analyze the transition according to the ‘two state model’: spins fl ip abruptly from initial angle to fi nal arrangement ( ). Obtained results suggest that spin reorientation process cannot be described using only the mentioned above model. Additional computer simulations based on the Yamada–Kato model were conducted to determine temperature range and the type of spin alignments in the vicinity of the transition. These theoretical results supported by spectra analysis suggest the existence of intermediate (canted) spin arrangements in the studied compounds. The spin arrangement diagram was constructed
Spin reorientation process in Tm_{2–x}Ho_{x}Fe_{14}B : analysis of conical arrangement based on Mössbauer spectra
The spin reorientation process in the Tm2–xHoxFe14B series of compounds was studied using 57Fe
Mössbauer spectroscopy over the temperature range 5.2–320 K with a focus on the analysis of conical spin
arrangement. Each compound was studied by precise Mössbauer scanning in the vicinity of the transition and
during the transition. By applying computer simulations based on the simplified Yamada-Kato model, as well
as on some literature data for R2Fe14B (R = Tm, Ho) compounds, the above series was selected for studies as it
contains compounds with different spin arrangements (axial, planar, conical). It was a crucial requirement for
obtaining unambiguous angular dependences when applying a simultaneous fitting procedure of Mössbauer spectra.
Such an extended procedure was applied which allowed the temperature dependence of the angle describing
the position of the magnetization vector to be obtained. The results were compared with those from theoretical
simulations. The spin arrangement diagram was constructed. A conical spin arrangement was confirmed over
a wide temperature range
Corbu’s Hands
[EN] The aim of presented paper is to grasp a sense in which Le Corbusier influenced his professional partners within
ATBAT at 35 rue de Sèvres in Paris. On the example of Iannis Xenakis (Greek) and Jerzy Sołtan (Pole), which curriculum
and experience will be superposed, authors wish to analyse a means in which the formation of Le Corbusier’s Collaborators
induced a profoundly individualistic paths of both apprentices. Moreover it enabled both artists to develop autonomous views
on creative activities, which still stayed in mutual compliance. That allows to speculate upon the forcefulness of approach
towards passing skills that Le Corbusier applied in his Studio. With a parallel example of two pavilions for the World’s Fare
Expo’58 in Brussels, it is presented how compatible, despite of being completely different in form, those two projects are[ES] El objetivo del articulo es comprender cómo Le Corbusier influenciado sus socios profesionales en ATBAT a los
35 rue de Sèvres en Paris. Con un ejemplo de Iannis Xenakis (griego) y Jerzy Sołtan (polaco), autores desean analizar un
medio en el que la formacion de Colaboradores de Le Corbusier indujo a profunda indualistas sendas de los dos aprendices.
Con un ejemplo paralelo de dos pabellones para Expo'58 Fare del Mundo en Bruselas, se presenta el grado de
compatibilidad, a pesar de ser completamente diferente en la forma, son los dos proyectos.Rumież, A.; Oleszak, W. (2016). Corbu’s Hands. En LE CORBUSIER. 50 AÑOS DESPUÉS. Editorial Universitat Politècnica de València. 1977-1985. https://doi.org/10.4995/LC2015.2015.948OCS1977198
A Study of Point Defects in the B2-Phase Region of the Fe-Al System by Mossbauer Spectroscopy
In this work, we employed the Mössbauer spectroscopy and X-ray powder diffraction in a study of point defect formation in intermetallic phases of the B2 structure of the Fe{Al system as a function of Al concentration. The
results are compared with the concentrations of point defect determined from positron annihilation data. In the MÄossbauer effect, two types of samples are investigated: Fe{Al alloys with few additives obtained by induction melting and Al-rich metallic powders produced by the self-decomposition method and intensive grinding of high energy in the electro-magneto-mechanical mill.
We present the values of the 57Fe isomer shift and quadrupole splitting for the components describing the point defect in the local environment of a MÄossbauer nuclide. The concentration of the Fe vacancies and Fe atoms
substituting Al (Fe{AS) are determined. The results showed that an increase in Al content causes an increase in vacancy and Fe{AS concentration
Structure and magnetic properties of Bi5Ti3FeO15 ceramics prepared by sintering, mechanical activation and EDAMM process. A comparative study
Three different methods were used to obtain Bi5Ti3FeO15 ceramics, i.e. solid-state sintering, mechanical activation (MA) with subsequent thermal treatment, and electrical discharge assisted mechanical milling (EDAMM). The structure and magnetic properties of produced Bi5Ti3FeO15 samples were characterized using X-ray diffraction and Mössbauer spectroscopy. The purest Bi5Ti3FeO15 ceramics was obtained by standard solid-state sintering method. Mechanical milling methods are attractive because the Bi5Ti3FeO15 compound may be formed at lower temperature or without subsequent thermal treatment. In the case of EDAMM process also the time of processing is significantly shorter in comparison with solid-state sintering method. As revealed by Mössbauer spectroscopy, at room temperature the Bi5Ti3FeO15 ceramics produced by various methods is in paramagnetic state
Aneurysmal Lesions of Patients with Abdominal Aortic Aneurysm Contain Clonally Expanded T Cells
Abdominal aortic aneurysm (AAA) is a common disease with often life-threatening consequences. This vascular disorder is responsible for 1-2% of all deaths in men aged 65 years or older. Autoimmunity may be responsible for the pathogenesis of AAA. Although it is well documented that infiltrating T cells are essentially always present in AAA lesions, little is known about their role in the initiation and/or progression of the disease. To determine whether T cells infiltrating AAA lesions contain clonally expanded populations of T cells, we amplified beta-chain TCR transcripts by the nonpalindromic adaptor-PCR/Vbeta-specific PCR and/or Vbeta-specific PCR, followed by cloning and sequencing. We report in this article that aortic abdominal aneurysmal lesions from 8 of 10 patients with AAA contained oligoclonal populations of T cells. Multiple identical copies of beta-chain TCR transcripts were identified in these patients. These clonal expansions are statistically significant. These results demonstrate that alphabeta TCR(+) T lymphocytes infiltrating aneurysmal lesions of patients with AAA have undergone proliferation and clonal expansion in vivo at the site of the aneurysmal lesion, in response to unidentified self- or nonself Ags. This evidence supports the hypothesis that AAA is a specific Ag-driven T cell disease
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