Search results for "TVE"
showing 10 items of 786 documents
Subjektīvās un objektīvās drošības atšķirības Rīgā: Lietotāju uztvere un digitālas segmentējamas kartes izstrāde
2021
Liela nozīme cilvēka ikdienas gaitās ir drošības uztverei apkārtējā vidē. To var ietekmēt dažāda veida faktori, tajā skaitā, noziegumu daudzums, satiksmes drošība, apgaismojums, apzaļojumi un pārskatāmība. Toties ne vienmēr cilvēka uztvertie faktori atbilst patiesajai situācijai. Lai noskaidrotu, kas ietekmē drošības uztveri Rīgā un vai tā atbilst patiesajai situācijai, tika veikts pētījums par vizuāli telpiskās drošības uztveri dažādos Rīgas reģionos, un tās ietekmējošiem faktoriem. Rezultātā tika izstrādāta tīmekļa lietotne, kurā digitālas kartes veidā tiek attēloti ievāktie dati, un veicot iegūto rezultātu analīzi, tika secināts, ka pastāv cieša korelācija starp izvirzītajiem drošību iet…
Epidemioloģisku situāciju uztveres telpiskā monitoringa rīka izveide
2021
Darba mērķis ir pētīt kā cilvēku uzskati, par kontaktu ar potenciāli saslimošu, atšķiras no ekspertu viedokļa, lai apzinātos kādi ir iespējamie veidi kā labāk samazināt atšķirību šajos uzskatos, kā uzlabot jau esošas sistēmas, kā monitorēt cilvēku attieksmi pret pandēmiju un atvieglot šo procesu. Par darba pamatu aptaujāto ikdienas cilvēku un ekspertu viedokļu salīdzinājumam, kalpos kursa darbā izveidota aptauja, kurā ir ievākta 32 cilvēku atbildes. Izmantojot šo aptauju, tiks ievāktas atbildes no cilvēkiem ar zināšanām par epidemioloģiju jeb ekspertiem un salīdzināts abu grupu viedoklis. Darba rezultātā tiks noskaidrots vai aptaujāto ikdienas cilvēku un ekspertu viedokļi, par epidemioloģis…
Didaktiskā rotaļa –fonemātiskās uztveres pilnveidošanas līdzeklis 5 – 6 gadīgiem bērniem ar fonētiski fonemātiskiem traucējumiem
2018
Diplomdarba „ Didaktiskā rotaļa – fonemātiskās uztveres pilnveidošanas līdzeklis 5 – 6 gadīgiem bērniem ar fonētiski fonemātiskiem traucējumiem” mērķis ir teorētiski un praktiski izzināt fonemātiskās uztveres pilnveides iespējas izmantojot didaktiskās rotaļas bērniem ar fonētiski fonemātiskiem traucējumiem. Tika izvirzīti šādi uzdevumi: 1.Izzināt psiholoģisko, pedagoģisko, logopēdisko literatūru problēmas skatījumā 2.Raksturot rotaļu koriģējoši attīstošo nozīmi fonemātiskās uztveres pilnveidošanā 3.Veikt pētījumu par didaktisko rotaļu izmantošanas iespējām fonemātiskās uztveres sekmēšanā bērniem ar fonētiski fonemātiskiem traucējumiem Diplomdarba izstrādē izmantotas teorētiskas un empīriskā…
Iron Doped-ZrSiO4: Structural, Microstructural and Vibrational Characterization
2015
Fex-ZrSiO4 is known for the applications in the ceramic industry such as ceramic pigment. In this article, we focus our attention to the structural, microstructural and vibrational changes of Fex-ZrSiO4 from free-mineralizer precursors, treated at different temperatures in the range of 1100-1600 °C. The refinements of X-ray diffraction patterns show that Fe3+ cations were distributed into tetrahedral sites replacing Si4+. The evolution of the shape distribution analyzed by transmission electron microscopy, reveal a polyhedral morphology at 1100 °C during 3h. In comparison, well-rounded and homogeneous particle size was determined in the sample heated at 1600 °C during 24 h. On the other han…
Discovery of new boron-rich chalcogenides: Orthorhombic B6X (X=S, Se)
2020
The authors thank T. Chauveau (LSPM) for help with Rietveld analysis, A. Jamali (LRCS) for assistance with SEM measurements, and Drs. Y. Tange (SPring-8) and N. Guignot (SOLEIL) for help in synchrotron experiments that were carried out during beamtimes allocated to proposals 2017A1047 & 2018A1121 at SPring-8 and proposal 20170092 at SOLEIL. Ab initio calculations have been performed using Rurik and Arkuda supercomputers. This work was financially supported by the European Union’s Horizon 2020 Research and Innovation Programme under Flintstone2020 project (grant agreement No. 689279). Z.W. thanks the National Science Foundation of China (grant No. 11604159). A.R.O. thanks the Russian Ministr…
New insight into δ-Pu alloy oxidation kinetics highlighted by using in-situ X-ray diffraction coupled with an original Rietveld refinement method
2018
Abstract The reactivity of a δ-Pu alloy was studied under dry oxygen at different temperatures. Phase analysis has shown the presence of α-and β-Pu2O3, PuO2, as well as the destabilisation of the δ-phase. The oxidation kinetics were studied using in-situ X-ray diffraction coupled with an original method of Rietveld refinement enabling an individual monitoring of the growth of each oxide. The results have evidenced a parabolic stage resulting from the thickening of the α-Pu2O3 layer, in which a compressive stress state develops. This stage is followed by the linear growth of a porous PuO2 scale.
Experimental and theoretical study to explain the morphology of CaMoO4 crystals
2018
Abstract CaMoO 4 crystals were prepared by a controlled co-precipitation method and processed in a domestic microwave-assisted hydrothermal system with two different surfactants (ethyl 4-dimethylaminobenzoate and 1,2,4,5-benzenetetracarboxylic dianhydride). The corresponding structures were characterized by X-ray diffraction and Rietveld refinement techniques, Fourier transform infrared spectroscopy, ultraviolet–visible absorption spectroscopy, and photoluminescence measurements. Field emission scanning electron microscopy was used to investigate the morphology of the as-synthesized aggregates. The structure, the surface stability of the (001), (112), (100), (110), (101), and (111) surfaces…
On the existence of a pyrochlore-type phase in the system Bi2O3–TiO2
1995
The existence of a bismuth titanate in the range between Bi 2 Ti 4 O 11 (Bi 2 O 3 . 4 TiO 2 ) and Bi 4 Ti 3 O 12 (2 Bi 2 O 3 . 3 TiO 2 ) has been investigated by X-ray diffraction of samples prepared by solid state reactions. For reaction temperatures above 1100 °C and a starting composition Bi 2 O 3 . 2 TiO 2 there appeared additional lines which could be attributed to a cubic face-centred cell with a = 10.354 A. A multiphase Rietveld analysis based on X-ray powder diffraction data confirmed the structural model of a pyrochlore for this compound. There is evidence that this phase belongs to the group of defect pyrochlores with a Bi 3+ -deficiency resulting in a composition of Bi 1.833 Ti 2…
Isomerism in [MCl2(ERR‘)2] (M = Pd, Pt; E = S, Se; R, R‘ = Me, Ph)
2006
A series of thioether and selenoether complexes [MCl2(EPh2)2] and [MCl2(SMePh)2] (M = Pt, Pd; E = S, Se) have been prepared and characterized to explore the isomerism of the complexes in solution and in the solid state. The NMR spectroscopic information indicates that only one isomer is present in solution in case of the palladium complexes, while two isomers are formed in the case of most platinum complexes. Single-crystal X-ray structures of trans-[PdCl2(SPh2)2] (1t), trans-[PdCl2(SePh2)2] (2t), cis-[PtCl2(SePh2)2] (4c), trans-[PdCl2(SMePh)2] (5t), and trans-[PtCl2(SMePh)2] (7t) are reported and have been used as starting points for the X-ray powder diffraction structure determinations us…
Cation Distribution in a Titanium Ferrite Fe2.75Ti0.25O4Measured byin-SituAnomalous Powder Diffraction Using Rietveld Refinement
1998
Many ferrites contain different cations with various valence states and location in the spinel structure. In compounds such as these, only a combination of different techniques such as Mussbauer spectroscopy, IR analysis, and thermogravimetry allows the distribution of cations to be obtained. For very complicated distributions, the mathematical decomposition of derivative thermogravimetric curves (DTG) leading to quantitative distribution is uncertain. In this paper, we present an alternative technique based on resonant diffraction. The anomalous scattering of each cation in the crystalline material is used to determine its amount and position by Rietveld refinement. Since the energy for su…