Search results for "RAV"
showing 10 items of 5866 documents
Autoparka pārvaldības risinājums transporta loģistikas uzņēmuma uzlabošanai
2019
Diplomdarba tēma ir autoparka pārvaldības risinājums transporta loģistikas uzņēmuma uzlabošanai. Darbā tiek pētīts transporta loģistikas raksturojums un attīstības iespējas uzņēmumā SIA “Auto”. Transportēšana ir viena no galvenajām loģistikas darbībām. Lai to darbība būtu maksimāli efektīva un lai to varētu sasniegt, ir nepieciešams veikt transporta autoparka uzraudzību. Tāpēc transporta uzņēmumi izmanto globālās pozicionēšanas sistēmas savam transportam. Uzņēmumā SIA “Auto” nav vienotas šādas sistēmas, jo šobrīd tiek izmantotas vairākas tādas. Tā kā uzņēmumam ir savs autoparks, darba autore uzskata, ka efektīvākam darbam vajadzētu visā autoparkā ieviest vienotu sistēmu, kas arī ikdienā atv…
Correlation between oxidation states of transition metal ions and variation of the coercivity in mixed-valence defect spinel ferrites
1997
Abstract Due to the very high dispersion of mixed-valence spinel ferrites prepared by ‘soft chemistry’ it becomes possible to oxidize in the spinel lattice, not only ferrous ions but also different transition metal ions (Cr 3+ , Mn 2+ , Mn 3+ , Mo 3+ , Mo 4+ V 2+ , V 3+ , Cu + ), by ‘soft’ oxidation between 150 and 500°C, under formation of non-stoichiometric spinels cation vacancies. The oxidation state with the coordination and the oxidation temperature of the cations have been determined in coppermanganese ferrites by derivative thermogravimetry (DTG), based on the specific solid-state reactivity of cations in the redox reaction. For Co-modified non-stoichiometric spinels, which present…
Characterization of the non-stoichiometry in lanthanum oxyfluoride by FT-IR absorption, Raman scattering, X-ray powder diffraction and thermal analys…
1997
Abstract The FT-IR absorption, FT-Raman scattering, X-ray powder diffraction (XPD), and thermogravimetry were used to explore the non-stoichiometry in LaOF. The TGA-DTA analyses between 30 and 1500°C showed that the LaO1 − xF1 + 2x phases yielded the stoichiometric LaOF as an intermediate product. The temperature of formation of the LaOF and La2O3 increased with increasing excess of fluoride. The room temperature XPD data in 6.5 ⩽ 2θ ⩽ 121° range were analyzed by the Rietveld profile refinement method and subsequently by the bond valence calculations. All LaO1 − xF1 + 2x phases possess the tetragonal PbFCl-type structure (space group: P4/nmm; Z = 2) while the stoichiometric LaOF has the hex…
Electronic structure of large disc-type donors and acceptors
2010
Searching for new pi-conjugated charge-transfer systems, the electronic structure of a new acceptor-donor pair derived from coronene (C(24)H(12)) was investigated by ultraviolet photoelectron spectroscopy (UPS). The acceptor coronene-hexaone (C(24)H(6)O(6), in the following abbreviated as COHON) and the donor hexamethoxycoronene (C(30)H(24)O(6), abbreviated as HMC) were adsorbed as pure and mixed phases on gold substrates. At low coverage, COHON adsorption leads to the appearance of a charge-transfer induced interface state 1.75 eV below the Fermi energy. At multilayer coverage the photoemission intensity of the interface state drops and the valence spectrum of neutral COHON appears. The sa…
Electronic structure of metal‐free phthalocyanine : A valence effective Hamiltonian theoretical study
1988
We present a valence effective Hamiltonian (VEH) nonempirical investigation of the electronic properties of metal‐free phthalocyanine. The valence one‐electron energy levels are related to those of the phthalocyanine components: benzene, pyrrole, and isoindole. From the electronic structure standpoint, phthalocyanine has to be viewed as formed by joining four benzene moieties to the central carbon–nitrogen ring rather than by combining four isoindole units through nitrogen bridges. Comparison of the VEH density‐of‐valence‐states curves with the experimental ultraviolet photoelectron spectroscopy (UPS) data is quantitatively excellent and allows for a complete interpretation of the experimen…
Valeurs de référence du valproate de sodium (CAS n°1069-66-5). Valeurs toxicologiques de référence par voie orale et inhalation, valeurs limites d’ex…
2021
Le site de Sanofi situé à Mourenx, dans le bassin industriel de Lacq (64), produit un médicament antiépileptique, la Dépakine®, dont le principe actif est le valproate de sodium (VPS). Ce site est une installation classée pour la protection de l’environnement (ICPE) soumise à autorisation au titre de l’article L.511-1 et suivants du Code de l’environnement. Les rejets dans l’environnement d’une telle installation sont encadrés par des limites établies sur la base d’une évaluation quantitative des risques sanitaires (EQRS). En 2017, Sanofi Chimie a réalisé une évaluation de l’impact sur la santé et l’environnement des rejets atmosphériques de valproate, en utilisant des valeurs toxicologique…
Krāsas 20. gadsimta antiutopiskajos romānos
2017
Šīs pētījums apskata krāsu izmantošanu, valodu un simbolismu 20. gadsimta antiutopiskajā literatūrā. Darba pamatuzdevums ir izpētīt krāsu paleti antiutopiskajos romānos: kādi krāsu termini ir izmantoti, kādas ir to galvenās funkcijas, simbolisms un konteksts. Lai sasniegtu šo mērķi, ir apskatīti pētījumi par krāsu simbolismu, kā arī tika savākti dati priekš kvantitatīvas and kvalitatīvas analīzes. Tika secināts, ka romānos Mēs, Brīnšķīgā jaunā pasaule un Kalpones stāsts izmantotās krāsas pārsvarā ir bāziskie krāsu termini, saskaņā ar Berlina un Keja teoriju. Terminiem ir trīs galvenās funkcijas: individualizēt varoni, akcentēt ‘utopisko’ valsts pilsoņu vienādību un raksturot ‘utopisko’ vals…
From corona virus to corona crisis : the value of an analytical and geographical understanding of crisis
2020
Abstract The term ‘crisis’ is omnipresent. The current corona virus pandemic is perceived as the most recent example. However, the notion of crisis is increasingly deployed as a signifier of relevance, rather than as an analytical concept. Moreover, human geography has so far little contributed to the interdisciplinary crisis research field which is fixated on the temporal aspects of crisis but neglects its spatiality. Against this background, the first aim of the paper is to demonstrate the value of thinking about crisis analytically. Therefore, we introduce theoretical knowledge developed within a recently emerging literature on crisis management. Second, we demonstrate the relevance of i…
Natural optical anisotropy of h-BN: Highest giant birefringence in a bulk crystal through the mid-infrared to ultraviolet range
2018
The giant birefringence of layered h-BN was demonstrated by analyzing the interference patterns in reflectance and transmittance measurements in the mid-infrared to the deep ultraviolet energy range. The refractive index for polarization perpendicular to the c axis is much higher than the refractive index for polarization parallel to the c axis, and it displays a strong increase in the ultraviolet range that is attributed to the huge excitonic effects arising from the unique electronic structure of h-BN. Thus, h-BN is shown to exhibit a giant negative birefringence that ranges from -0.7 in the visible to -2 in the deep ultraviolet close to the band gap. The electronic dielectric constants f…
Polidoro da Caravaggio (1499 ca.-1543)
2011
Nell'ambito degli artisti siciliani, o attivi in Sicilia, citati da Giorgio Vasari ne "Le vite de più eccellenti, pittori, scultori et architettori", il testo analizza la biografia e l'attività a Messina dell'architetto e pittore Polidoro da Caravaggio nel primo Cinquecento.