995 resultados para 7140-220
Resumo:
The Raman spectrum of lithium hydrazinium sulphate has been recorded both in the single crystal form and in aqueous solutions. The crystal exhibits thirty-eight Raman lines having the frequency shifts 52, 70, 104, 146, 174, 220, 260, 302, 350, 454, 470, 610, 630, 715, 977, 1094, 1115, 1132, 1177, 1191, 1260, 1444, 1493, 1577, 1630, 1670, 2205, 2484, 2553, 2655, 2734, 2848, 2894, 2939, 3028, 3132, 3290 and 3330 cm.−1 The aqueous solution gave rise to six Raman lines at 452, 980, 1050–1200, 1260, 1425 and 1570 cm.−1 apart from a maximum at 180 cm.−1 in the ‘wing’ accompanying the Rayleigh line. The observed Raman lines have been assigned as arising from the vibrations of the SO4 ion, N2H5+ ion, Li-O4 group, hydrogen bond and the lattice. The influence of the hydrogen bond on the N-H stretching vibrations has been pointed out. The various features of the observed spectrum strongly support the hypothesis that the NH3 group in the crystal is rotating around the N-N axis at room temperature.
Resumo:
We show that the dynamical Wigner functions for noninteracting fermions and bosons can have complex singularity structures with a number of new solutions accompanying the usual mass-shell dispersion relations. These new shell solutions are shown to encode the information of the quantum coherence between particles and antiparticles, left and right moving chiral states and/or between different flavour states. Analogously to the usual derivation of the Boltzmann equation, we impose this extended phase space structure on the full interacting theory. This extension of the quasiparticle approximation gives rise to a self-consistent equation of motion for a density matrix that combines the quantum mechanical coherence evolution with a well defined collision integral giving rise to decoherence. Several applications of the method are given, for example to the coherent particle production, electroweak baryogenesis and study of decoherence and thermalization.
Resumo:
Statistical learning algorithms provide a viable framework for geotechnical engineering modeling. This paper describes two statistical learning algorithms applied for site characterization modeling based on standard penetration test (SPT) data. More than 2700 field SPT values (N) have been collected from 766 boreholes spread over an area of 220 sqkm area in Bangalore. To get N corrected value (N,), N values have been corrected (Ne) for different parameters such as overburden stress, size of borehole, type of sampler, length of connecting rod, etc. In three-dimensional site characterization model, the function N-c=N-c (X, Y, Z), where X, Y and Z are the coordinates of a point corresponding to N, value, is to be approximated in which N, value at any half-space point in Bangalore can be determined. The first algorithm uses least-square support vector machine (LSSVM), which is related to aridge regression type of support vector machine. The second algorithm uses relevance vector machine (RVM), which combines the strengths of kernel-based methods and Bayesian theory to establish the relationships between a set of input vectors and a desired output. The paper also presents the comparative study between the developed LSSVM and RVM model for site characterization. Copyright (C) 2009 John Wiley & Sons,Ltd.
A study of the purification and properties of tryptophan synthetase of Bengal gram (Cicer arietinum)
Resumo:
Active preparations of tryptophan synthetase were obtained from Bengal gram (Cicer arietinum) by the following procedure: (1) precipitation of inactive materials by manganous sulfate, (2) Adsorption of impurities on Alumina Cγ, (3) Adsorption of tryptophan synthetase on tricalcium phosphate gel, removal of inert protein from the gel by treatment with phosphate buffer (pH 7.2), and selective elution of the enzyme by 0.15 M phosphate buffer pH 7.2 containing 10% ammonium sulfate and 10−3 M serine. A 220-fold purification of the enzyme with 44% recovery of the activity was achieved. The pH optimum, effect of temperature, and substrate concentration and other properties of the purified enzyme have been studied in detail. Only the Image -isomer of serine takes part in the reaction. The Km values for indole, Image -serine, and Image -serine were calculated to be 0.66, 4.1, and 8.6 × 10−4 M, respectively. A kinetic study of the inhibition of tryptophan synthetase by indole-propionic acid has shown that it is of a competitive type. It has been demonstrated for the first time that 4-nitro-salicylaldehyde can replace pyridoxal phosphate as a coenzyme for the tryptophan synthetase reaction.
Resumo:
Lappiin suunnitteilla olevat Pajala–Kolarin rauta- ja Soklin fosforikaivos ovat megaluokan hankkeita. Kaivosten rakentaminen ei voi kuitenkaan toteutua jos niiden tarvitsemia rautatie-, satama- ja tieinvestointeja ei voida toteuttaa. Tutkimuksen tavoitteena oli arvioida näiden väyläinvestointien aluetaloudellisia vaikutuksia. Tutkimus on jatkoa Ruraliassa juuri valmistuneelle yhdeksää Pohjois- ja Itä-Suomen kaivoshanketta koskevalle tutkimukselle, jossa keskitytään itse kaivosinvestointien vaikutuksiin. Tutkimuksen on rahoittanut Liikenne- ja viestintäministeriö yhdessä Työ- ja elinkeinoministeriön kanssa. Työvälineenä oli Ruraliassa kehitetty RegFinDyn-aluemalli. Simuloinnit suoritettiin vuosille 2008–2030 ja raportoitiin Lapin seutukuntien tasolla. Tulosten mukaan kaikki, mutta erityisesti mittavat rautatieinvestoinnit olisivat merkittäviä seutukuntien taloudelliselle kasvulle. Äkäsjoki–Ajos radan rakentaminen auttaisi Tunturi-Lapin, Torniolaakson ja Kemi–Tornion seutukuntia taantuman yli. Taloudellinen kasvu voisi lisääntyä läntisen Lapin seutukunnissa yhteensä 0,6–2,2% vuoteen 2011 ja yhteensä 1,3–4,3% vuoteen 2016 mennessä. Tämä olisi keskimäärin 0,1–0,5% vuodessa. Soklin kaivoksen tapauksessa Kemijärvi–Kelloselkä–Sokli rautatien vaikutukset Itä- ja Pohjois-Lapin seutukuntiin olisivat merkittäviä. Investointien edetessä Itä-Lapin seutukunnan taloudellinen kasvu voisi vahvistua kumulatiivisesti tarkasteltuna 8,3% vuoteen 2013 mennessä. Vuosikeskiarvona tämä olisi 2,8%. Radan vaikutus Pohjois-Lapin taloudelliseen kasvuun olisi pienempi, vuoteen 2014 mennessä yhteensä 3% eli keskimäärin 0,8% vuodessa. Väyläinvestointien työllisyysvaikutukset olisivat myönteisiä. Pajala–Kolarin kaivoksen rautatieinvestoinnit toisivat läntiseen Lappiin uusia työpaikkoja vuoteen 2015 mennessä yhteensä 418. Tästä Tunturi-Lapin osuus olisi 147, Torniolaakson 114 ja Kemi–Tornion seutukunnan 157. Vastaavat vuosikeskiarvot olisivat 52, 18, 14 ja 20. Soklin kaivoksen rautatieinvestoinnit toisivat jonkun verran enemmän uusia työpaikkoja Pajala–Kolariin verrattuna koska investoinnit olisivat suuremmat. Radan rakentaminen voisi tuoda Itä-Lappiin yhteensä 506 uutta työpaikkaa vuoden 2013 loppuun mennessä. Pohjois-Lapin työllisyys voisi lisääntyä 153 uudella työpaikalla. Yhteensä voisi siten syntyä 660 uutta työpaikkaa. Vastaavat vuosikeskiarvot olisivat 169, 51, 220 uutta työpaikkaa. Kun kaivoksia tarkastellaan yhdessä, työllisyysvaikutukset olisivat suurimmat vuonna 2015, jonka loppuun mennessä väyläinvestoinnit voisivat luoda yhteensä 1288 uutta työpaikkaa. Vastaava vuosikeskiarvo olisi 161. Taloudellisen kasvun ohella työllisyystulokset korostavat analysoitujen väyläinvestointien myönteistä aluetaloudellista merkitystä. Ruralia-instituutin arvioinnin perusteella molempien kaivosten rautatie-, satama- ja tieinvestoinnit olisivat toteuttamiskelpoisia aluetaloudellisin perustein. Ne lisäisivät tuotantoa, työllisyyttä, tuloja, kulutusta ja verotuloja useissa Lapin seutukunnissa.
Resumo:
Ingarden (1962, 1964) postulates that artworks exist in an “Objective purely intentional” way. According to this view, objectivity and subjectivity are opposed forms of existence, parallel to the opposition between realism and idealism. Using arguments of cognitive science, experimental psychology, and semiotics, this lecture proposes that, particularly in the aesthetic phenomena, realism and idealism are not pure oppositions; rather they are aspects of a single process of cognition in different strata. Furthermore, the concept of realism can be conceived as an empirical extreme of idealism, and the concept of idealism can be conceived as a pre-operative extreme of realism. Both kind of systems of knowledge are mutually associated by a synecdoche, performing major tasks of mental order and categorisation. This contribution suggests that the supposed opposition between objectivity and subjectivity, raises, first of all, a problem of translatability, more than a problem of existential categories. Synecdoche seems to be a very basic transaction of the mind, establishing ontologies (in the more Ingardean way of the term). Wegrzecki (1994, 220) defines ontology as “the central domain of philosophy to which other its parts directly or indirectly refer”. Thus, ontology operates within philosophy as the synecdoche does within language, pointing the sense of the general into the particular and/or viceversa. The many affinities and similarities between different sign systems, like those found across the interrelationships of the arts, are embedded into a transversal, synecdochic intersemiosis. An important question, from this view, is whether Ingardean’s pure objectivities lie basically on the impossibility of translation, therefore being absolute self-referential constructions. In such a case, it would be impossible to translate pure intentionality into something else, like acts or products.
Resumo:
W/Cr codoped Bi4Ti3O12 ceramics, Bi4Ti3-xWxO12+x+0.2 wt%Cr2O3 (BITWC, x=0-0.15), were prepared using a solid-state reaction method. The crystallographic evolution and phase analysis were distinctly determined focusing on the X-ray diffraction peak changes in (020)/(200) and (220)/(1115) diffraction planes, by which the lattice parameters, a, b, and c can be refined. The thermal variations of permittivity, dielectric loss (tan delta), impedance, and electrical conductivity properties were characterized. A decrease in the values of Curie temperature from 675 degrees to 640 degrees C and an increase in the values of the dielectric constant due to an increase of W6+/Cr3+ content were observed. The highest piezoelectric constant, d(33) of 22 pC/N, was achieved with the composition of Bi4Ti2.975W0.025O12.025+0.2 wt% Cr2O3. Also, this composition had a lower electrical conductivity than the other investigated compositions.
Resumo:
Aspects of large-scale organized structures in sink flow turbulent and reverse-transitional boundary layers are studied experimentally using hot-wire anemometry. Each of the present sink flow boundary layers is in a state of 'perfect equilibrium' or 'exact self-preservation' in the sense of Townsend (The Structure of Turbulent Shear Flow, 1st and 2nd edns, 1956, 1976, Cambridge University Press) and Rotta (Progr. Aeronaut. Sci., vol. 2, 1962, pp. 1-220) and conforms to the notion of 'pure wall-flow' (Coles, J. Aerosp. Sci., vol. 24, 1957, pp. 495-506), at least for the turbulent cases. It is found that the characteristic inclination angle of the structure undergoes a systematic decrease with the increase in strength of the streamwise favourable pressure gradient. Detectable wall-normal extent of the structure is found to be typically half of the boundary layer thickness. Streamwise extent of the structure shows marked increase as the favourable pressure gradient is made progressively severe. Proposals for the typical eddy forms in sink flow turbulent and reverse-transitional flows are presented, and the possibility of structural self-organization (i.e. individual hairpin vortices forming streamwise coherent hairpin packets) in these flows is also discussed. It is further indicated that these structural ideas may be used to explain, from a structural viewpoint, the phenomenon of soft relaminarization or reverse transition of turbulent boundary layers when subjected to strong streamwise favourable pressure gradients. Taylor's 'frozen turbulence' hypothesis is experimentally shown to be valid for flows in the present study even though large streamwise accelerations are involved, the flow being even reverse transitional in some cases. Possible conditions, which are required to be satisfied for the safe use of Taylor's hypothesis in pressure-gradient-driven flows, are also outlined. Measured convection velocities are found to be fairly close to the local mean velocities (typically 90% or more) suggesting that the structure gets convected downstream almost along with the mean flow.
Resumo:
Modeling and forecasting of implied volatility (IV) is important to both practitioners and academics, especially in trading, pricing, hedging, and risk management activities, all of which require an accurate volatility. However, it has become challenging since the 1987 stock market crash, as implied volatilities (IVs) recovered from stock index options present two patterns: volatility smirk(skew) and volatility term-structure, if the two are examined at the same time, presents a rich implied volatility surface (IVS). This implies that the assumptions behind the Black-Scholes (1973) model do not hold empirically, as asset prices are mostly influenced by many underlying risk factors. This thesis, consists of four essays, is modeling and forecasting implied volatility in the presence of options markets’ empirical regularities. The first essay is modeling the dynamics IVS, it extends the Dumas, Fleming and Whaley (DFW) (1998) framework; for instance, using moneyness in the implied forward price and OTM put-call options on the FTSE100 index, a nonlinear optimization is used to estimate different models and thereby produce rich, smooth IVSs. Here, the constant-volatility model fails to explain the variations in the rich IVS. Next, it is found that three factors can explain about 69-88% of the variance in the IVS. Of this, on average, 56% is explained by the level factor, 15% by the term-structure factor, and the additional 7% by the jump-fear factor. The second essay proposes a quantile regression model for modeling contemporaneous asymmetric return-volatility relationship, which is the generalization of Hibbert et al. (2008) model. The results show strong negative asymmetric return-volatility relationship at various quantiles of IV distributions, it is monotonically increasing when moving from the median quantile to the uppermost quantile (i.e., 95%); therefore, OLS underestimates this relationship at upper quantiles. Additionally, the asymmetric relationship is more pronounced with the smirk (skew) adjusted volatility index measure in comparison to the old volatility index measure. Nonetheless, the volatility indices are ranked in terms of asymmetric volatility as follows: VIX, VSTOXX, VDAX, and VXN. The third essay examines the information content of the new-VDAX volatility index to forecast daily Value-at-Risk (VaR) estimates and compares its VaR forecasts with the forecasts of the Filtered Historical Simulation and RiskMetrics. All daily VaR models are then backtested from 1992-2009 using unconditional, independence, conditional coverage, and quadratic-score tests. It is found that the VDAX subsumes almost all information required for the volatility of daily VaR forecasts for a portfolio of the DAX30 index; implied-VaR models outperform all other VaR models. The fourth essay models the risk factors driving the swaption IVs. It is found that three factors can explain 94-97% of the variation in each of the EUR, USD, and GBP swaption IVs. There are significant linkages across factors, and bi-directional causality is at work between the factors implied by EUR and USD swaption IVs. Furthermore, the factors implied by EUR and USD IVs respond to each others’ shocks; however, surprisingly, GBP does not affect them. Second, the string market model calibration results show it can efficiently reproduce (or forecast) the volatility surface for each of the swaptions markets.
Resumo:
Results are presented to show that as the thermal decomposition of orthorhombic ammonium perchlorate proceeds there is an accumulation, in the solid, of hydrochloric and nitric acids, the concentrations of which increase up to 15% decomposition after which they decrease until they reach the original values.