Classical Physics

Direct composition measurements are made on equilibrium vapour and liquid phases of a five-component model gas condensate sample. The compositions of equilibrium phases are measured at two temperatures (303.15 and 353.15 K) and pressures of 30.44-19.41 MPa. Component balance calculations and evaluation of the internal consistency of the measured equilibrium ratios of components demonstrate the reliability of measurements.

We report the advantages and drawbacks of three protocols (adjustment, AFC-yes/no, and AFC-left/right discrimination protocols)e valuating the estimation of the interaural time differences (ITDs)f or correct lateralization perception. The protocols were compared with respect to reliability of the perceivedITD and just noticeable difference (JND)e stimations, robustness to participants' errors, effect of the number of tested blocks of trials, and test duration. Binaural stimuli were employed, including all spatial cues for sound sources placed at horizontal positions of 30 • and 90 • .All three protocols yielded comparable perceivedITD butdifferent JNDs at 30 •. At 90 • ,b oth the AFC-left/right and the adjustment protocols were more problematic than the yes/no protocol. Overall, only the yes/no protocol fulfilled the requirements of this study,i.e. aquick protocol that can be used for all angles.

Abstract Electric and Hybrid Electric vehicles (EV and HEV) seem to be the future of transport in smart cities and the key for the total reduction of noise disturbance and pollution in urban areas. However, several problems have to be solved to guarantee the safety of these types of vehicle. Up to now, the use of HEV has shown the dangers of a “quiet” transport system in urban environments; in fact, it has been estimated that an HEV is twice as likely to be involved in a pedestrian crash as would be an internal combustion engine (ICE) vehicle in the same situation. With the aim of improving their safety, different kinds of warning sounds are being designed to increase the detectability of EV and HEV without themselves becoming new annoying sound sources. The sound directivity, frequency of emission and intensity of warning sound systems will guarantee their efficiency and limited noise impact. Several research works bring to the fore a significant variation of the pedestrian response time to different acoustic stimuli. However, it is necessary to examine the suitability of these warning sounds according to the urban environments in which they are going to be emitted. Distinct areas inside the city have different soundscapes whose spectral content can vary significantly, masking some of the sounds suggested as an alert. This paper analyses in detail the main characteristics of several warning sounds proposed by the industry, conducting a comparative study of the different design trends. A total of 131 sighted listeners were exposed to a virtual road-crossing test. The behaviour and appropriateness of warning sounds are analysed depending on the urban environment. For this purpose, three clearly different soundscapes have been selected: stopped vehicles at a traffic light, a pedestrian shopping area and the vicinity of a playground. The results highlight the wide variability in pedestrian reaction time for the different warning sounds used. Some signals considerably improve the detectability of the vehicle, providing results even above the ICE vehicle ones. However, other warning sounds do not decrease the reaction time with respect to the EV. In addition, a clear dependence is observed between the detectability and the soundscape involved, changing the results for the same warning sound depending on the acoustic environment.

The paper presents the results of applying nonlocal means (NLMs) approach in the problem of separating respiration and cardiac sounds in a signal recorded on a human chest wall. The performance of the algorithm was tested both by simulated and real signals. As a quantitative efficiency measure of NLM filtra tion, the angle of divergence between isolated and reference signal was used. It is shown that for a wide range of signal to noise ratios, the algorithm makes it possible to efficiently solve this problem of separating cardiac and respiration sounds in the sum signal recorded on a human chest wall.

In this study, artificial neural networks (ANNs) were applied to predict the mean monthly wind speed of any target station using the mean monthly wind speeds of neighboring stations which are indicated as reference stations. Hourly wind speed data, collected by the Turkish State Meteorological Service (TSMS) at 8 measuring stations located in the eastern Mediterranean region of Turkey were used. The long-term wind data, containing hourly wind speeds, directions and related information, cover the period between 1992 and 2001. These data were divided into two sections. According to the correlation coefficients, reference and target stations were defined. The mean monthly wind speeds of reference stations were used and also corresponding months were specified in the input layer of the network. On the other hand, the mean monthly wind speed of the target station was utilized in the output layer of the network. Resilient propagation (RP) learning algorithm was applied in the present simulation. The hidden layers and output layer of the network consist of logistic sigmoid transfer function (logsig) and linear transfer function (purelin) as an activation function. Finally, the values determined by ANN model were compared with the actual data. The maximum mean absolute percentage error was found to be 14.13% for Antakya meteorological station and the best result was found to be 4.49% for Mersin meteorological station. r

The Sweet-Parker layer in a system that exceeds a critical value of the Lundquist number ͑S͒ is unstable to the plasmoid instability. In this paper, a numerical scaling study has been done with an island coalescing system driven by a low level of random noise. In the early stage, a primary Sweet-Parker layer forms between the two coalescing islands. The primary Sweet-Parker layer breaks into multiple plasmoids and even thinner current sheets through multiple levels of cascading if the Lundquist number is greater than a critical value S c Ӎ 4 ϫ 10 4 . As a result of the plasmoid instability, the system realizes a fast nonlinear reconnection rate that is nearly independent of S, and is only weakly dependent on the level of noise. The number of plasmoids in the linear regime is found to scales as S 3/8 , as predicted by an earlier asymptotic analysis ͓N. F. Loureiro et al., Phys. Plasmas 14, 100703 ͑2007͔͒. In the nonlinear regime, the number of plasmoids follows a steeper scaling, and is proportional to S. The thickness and length of current sheets are found to scale as S −1 , and the local current densities of current sheets scale as S −1 . Heuristic arguments are given in support of theses scaling relations.

Translations are often applied on equations of state with the aim of improving the description of molar volumes. In the present note an alternative presentation of the ideas developed in the pioneering work of Ptneloux and Rauzy [PCneloux, A., E. Rauzy, A consistent correction for Redlich-Kwong-Soave volumes. Fluid Phase Equilib., 8 (1982) 7-23.1 is provided and some issues are discussed in a deeper level of detail. 0 1997 Elsevier Science B.V. Key~~wds: Model; Equation of state; Volume; Vapor pressure; Mixture: Translations * Corresponding author 0378.3812/97/$17.00 0 1997 Elsevier Science B.V. All rights reserved. /'II s037x-~x12(97)00185-4

Drift wave maps, area preserving maps that describe the motion of charged particles in drift waves, are derived. The maps allow the integration of particle orbits on the long time scale needed to describe transport. Calculations using the drift wave maps show that dramatic improvement in the particle confinement, in the presence of a given level and spectrum of EϫB turbulence, can occur for q(r) profiles with reversed shear. A similar reduction in the transport, i.e., one that is independent of the turbulence, is observed in the presence of an equilibrium radial electric field with shear. The transport reduction, caused by the combined effects of radial electric field shear and both monotonic and reversed shear magnetic q profiles, is also investigated.

By using the backward fractional Fokker-Planck equation we investigate the barrier crossing event in the presence of Lévy noise. After shortly review recent results obtained with different approaches on the time characteristics of the barrier crossing, we derive a general differential equation useful to calculate the nonlinear relaxation time. We obtain analytically the nonlinear relaxation time for free Lévy flights and a closed expression in quadrature of the same characteristics for cubic potential.

Ion acceleration from short pulse laser interactions at intensities of 2 Â 10 21 Wcm À2 was studied experimentally under a wide variety of parameters, including laser contrast, incidence angle, and target thickness. Trends in maximum proton energy were observed, as well as evidence of improvement in the acceleration gradients by using dual plasma mirrors over traditional pulse cleaning techniques. Extremely high efficiency acceleration gradients were produced, accelerating both the contaminant layer and high charge state ions from the bulk of the target. Two dimensional particle-in-cell simulations enabled the study of the influence of scale length on submicron targets, where hydrodynamic expansion affects the rear surface as well as the front. Experimental evidence of larger electric fields for sharp density plasmas is observed in simulation results as well for such targets, where target ions are accelerated without the need for contaminant removal. V C 2013 AIP Publishing LLC. [http://dx.

A new photopyroelectric (PPE) methodology, for optical characterization of general liquids, was used for the assessment of hemoglobin in human blood. The optical absorption coefficient of a hemoglobin reference was measured with this PPE methodology and its corresponding absorptivity, at 532 nm, was obtained. This last reference was used for hemoglobin quantification of blood from a healthy man.

Deep eutectic solvents (DESs) are considered as the new ionic liquids (ILs) analogues that have emerged as potential alternative 'green' solvents, for a diversity of applications. In this study, a type III DES based on ammonium salt was investigated as an alternative solvent to currently employed conventional organic solvents in separation processes. Activity coefficients at infinite dilution, g ∞ 13 for 19 organic solutes in the tetramethylammonium chloride þ ethylene glycol DES were measured by the gas-liquid chromatography (GLC) method at four temperatures in the range from (313.15e343.15) K. Experimental measurements were undertaken with an overall uncertainty of ±5.4%. The effect of the structure of the solutes on g ∞ 13 was also investigated. For all investigated solutes, Gibbs helmholtz relationship was utilised to derive partial molar excess enthalpy values at infinite dilution (DH E;ð∞Þ i) from experimental limiting activity coefficient data. From selectivity (S ∞ ij) and capacity (k ∞ j) values at infinte dilution, it was concluded that the investigated DES has the potential to replace a number of industrial solvents for the separation of various industrial mixtures.

A new mwrocomputer-based system ts descrtbed whtch has been developed for the assessment and development of smgmg abthty lt makes use of a spectally developed hardware interface whwh esttmates the fundamental frequency of a sung or spoken mput as the basts for (a) a measurement of vocal pttchmg accuracy (assessment), and (b) a vocal pttch &splay to provtde msual feedback (development) Results are dtscussed whwh are based on a study carrted out wtth the syatem in a Brtttsh prtmary school, and they mdtcate that this system ts effecttve m promotmg singing development

Fast ignition requires a precise knowledge of fast electron propagation in a dense hydrogen plasma. In this context, a dedicated HiPER (High Power laser Energy Research) experiment was performed on the VULCAN laser facility where the propagation of relativistic electron beams through cylindrically compressed plastic targets was studied. In this paper, we characterize the plasma parameters such as temperature and density during the compression of cylindrical polyimide shells filled with CH foams at three different initial densities. X-ray and proton radiography were used to measure the cylinder radius at different stages of the compression. By comparing both diagnostics results with 2D hydrodynamic simulations, we could infer densities from 2 to 11 g=cm 3 and temperatures from 30 to 120 eV at maximum compression at the center of targets. According to the initial foam density, kinetic, coupled (sometimes degenerated) plasmas were obtained. The temporal and spatial evolution of the resulting areal densities and electrical conductivities allow for testing electron transport in a wide range of configurations. V

The penetration of magnetic flux into a thin superconducting film of Nb 3 Sn with critical temperature 17.8 K and critical current density 6 MA/cm 2 was visualized using magneto-optical imaging. Below 8 K an avalanche-like flux penetration in form of big and branching dendritic structures was observed in response to increasing perpendicular applied field. When a growing dendritic branch meets a linear defect in the film, several scenarios were observed: the branch can turn and propagate along the defect, continue propagation right through it, or ''tunnel'' along a flux-filled defect and continue growth from its other end. The avalanches manifest themselves in numerous small and random jumps found in the magnetization curve.

Tonal noise emitted from large-diameter spray dryer exhaust stacks used in the dairy industry can give rise to complaints from nearby communities. In many cases, the tone at the fan blade passing frequency is characterized by a frequency above the first mode cut on frequency of the exhaust stack and both its amplitude and the frequency are time varying. The variation in amplitude is a result of turbulence and temperature variations in the duct which cause angular variations in the nodal plane of modes with diametrical nodes. This in turn results in large fluctuations in sound pressure with time at any specified location in the duct, thus presenting a significant challenge for an ANC system with fixed control source and error sensor locations. In many food processing industries, the use of sound absorptive materials in silencers is not acceptable and, particularly when the fan speed is variable, it is difficult to achieve an acceptable passive solution at a reasonable cost. Here, the design and implementation of an active noise control system for tonal noise propagating above the cut-on frequency of the first higher order mode in large size cylindrical industrial exhaust stack is discussed, where the frequency and amplitude vary significantly and relatively rapidly with time. Physical system design principles and control algorithm optimization for a practical active noise control system are 0003-682X/$ -see front matter Ó .au (X. Li).

This work shows the experimental data of excess properties at several temperatures and the vapor–liquid equilibria (VLE) obtained for four binary systems of alkyl methanoates (methyl to butyl) with decane, all measured at constant pressure of 101.32kPa. The isobaric VLE data were thermodynamically consistent according to the Fredenslund test and did not present an azeotrope. The experimental data of HmE

Simple and inexpensive low-temperature bolometers have been fabricated using commercial thick-film resistors. The bolometer resistance depends both on the temperature and on the bias voltage. The responsivity and time constant are deduced in this non-ideal case.

A method using artificial neural network (ANN) was applied to estimate the vapor-liquid equilibrium (VLE) for the binary systems containing hydrofluoroethers (HFEs) and polar compounds. Our new estimation method is composed of three steps. In the first step, the sign of logarithm of activity coefficient (γ ) is estimated for each binary system using ANN, because it had been found that the binary systems containing HFEs show different thermodynamic behaviors depending on the sign for ln(γ ). In the second step, two sets of relation between liquid mole fraction and ln(γ ) are constructed: one held for the case of positive sign and the other held for that of negative sign. In the third step, vapor-liquid composition and equilibrium temperature are calculated using the estimated activity coefficient. In order to construct this new method, the isobaric VLE data of 18 binary systems including HFEs was used. As a result, our new method could estimate VLE with reasonable accuracy.

The problem presented in the paper belongs to a wide subject concerning the use of multimedia technology for the improvement of educational activities in museums and for attracting the audience with objects of art. Several examples of temporal and regular multimedia performances in galleries are known in Poland and abroad, but still the technology is not fully used in traditional museums. In the paper, the case study of multimedia presentation devoted to the collection of the historical instruments from the Museum of Musical Instruments in Poznań is described. By their nature, musical instruments are interactive, but for the reasons of security and costs, only on rare occasions may visitors listen to their sound. Multimedia can change this situation. The inspiration for creating the multimedia presentation was the 250th Anniversary of Wolfgang Amadeus Mozart birth. The historical 18th century instruments from the collection of the museum accompanied by the music of the composer have been virtually exposed. Shown during the "Museums Night" in May 2006, the presentation has gained interest of hundreds of guests and proved useful for future educational actions.

In magnetic fusion devices, radio frequency ͑rf͒ waves in the electron cyclotron ͑EC͒ and lower hybrid ͑LH͒ range of frequencies are being commonly used to modify the plasma current profile. In ITER, EC waves are expected to stabilize the neoclassical tearing mode ͑NTM͒ by providing current in the island region ͓R. Aymar et al., Nucl. Fusion 41, 1301 ͑2001͔͒. The appearance of NTMs severely limits the plasma pressure and leads to the degradation of plasma confinement. LH waves could be used in ITER to modify the current profile closer to the edge of the plasma. These rf waves propagate from the excitation structures to the core of the plasma through an edge region, which is characterized by turbulence-in particular, density fluctuations. These fluctuations, in the form of blobs, can modify the propagation properties of the waves by refraction. In this paper, the effect on rf due to randomly distributed blobs in the edge region is studied. The waves are represented as geometric optics rays and the refractive scattering from a distribution of blobs is formulated as a Fokker-Planck equation. The scattering can have two diffusive effects-one in real space and the other in wave vector space. The scattering can modify the trajectory of rays into the plasma and it can affect the wave vector spectrum. The refraction of EC waves, for example, could make them miss the intended target region where the NTMs occur. The broadening of the wave vector spectrum could broaden the wave generated current profile. The Fokker-Planck formalism for diffusion in real space and wave vector space is used to study the effect of density blobs on EC and LH waves in an ITER type of plasma environment. For EC waves the refractive effects become important since the distance of propagation from the edge to the core in ITER is of the order of a meter. The diffusion in wave vector space is small. For LH waves the refractive effects are insignificant but the diffusion in wave vector space is important. The theoretical model is general enough to study the effect of density blobs on all propagating cold plasma waves.

New absolute measurements, by the transient hot-wire technique, of the thermal conductivity of n-hexadecane and binary mixtures of n-hexadecane with ethanol and n-decane with butanol are presented. The temperature range examined was 295-345 K and the pressure atmospheric. The concentrations of the mixtures studied were 92% (by weight) of n-hexadecane and 30 and 70% (by weight) of n-decane. The overall uncertainty in the reported thermal conductivity data is estimated to be _+0.5%, an estimate confirmed by the measurement of the thermal conductivity of water. A recently extended semiempirical scheme for the prediction of the thermal conductivity of mixtures from the pure components is used to correlate and predict the thermal conductivity of these mixtures, as a function of both composition and temperature.

A time-domain formulation for sound propagation in rigid-frame porous media, including waveform attenuation and dispersion, is developed. The new formulation is based on inversion of the relaxation functions from a previous model [Wilson DK, Ostashev VE, Collier SL. J Acoust Soc Am 2004;116:1889-92], thereby casting the convolution integrals in a form amenable to numerical implementation. Numerical techniques are developed that accurately implement the relaxational equations and transparently reduce to previous results in low-and high-frequency limits. The techniques are demonstrated on calculations of outdoor sound propagation involving hills, barriers, and ground surfaces with various material properties. We also compare the relaxation formulation to a widely applied phenomenological model developed by Zwikker and Kosten. The two models can be made equivalent if the resistance constant, structure constant, and compression modulus in the ZK model are allowed to be weakly frequency dependent. But if the ZK parameters are taken to be constant, as is typically the case, the relaxation model provides more accurate calculations of attenuation by acoustically soft porous materials such as snow, gravel, and forest litter.

Densities were measured for the liquid benzene and 1,3,5-trimethylbenzene, and for nine of their mixtures at four temperatures between 298.15 and 328.15 K and at pressures up to 40 MPa. An apparatus for density measurements of liquids and liquid mixtures whose main part is a high-pressure vibrating-tube densimeter working in a static mode was used for the measurement. The density data were fitted to the Tait equation and the isothermal compressibilities were calculated with the aid of this equation. Excess molar volumes were also calculated from the densities and fitted to the Redlich-Kister equation.

ABSTRACT The sound of a solid body electric guitar comes from the loudspeaker transducing into sound the string velocity. Because of mechanical string-structure coupling, the string vibration, and therefore the sound, substantially depends on the lutherie parameters. This study focuses on the comparison between ebony-fingerboard and rosewood-fingerboard guitars: is a change in the fingerboard wood perceived by the guitar players? In order to test the hypothesis that it is actually perceived, a psychological investigation is carried out. Two experimental methods are used: a free sorting task with recorded stimuli from the guitars (listening test) and a free verbalisation task where the guitarists play the guitars. In the listening test, the guitarists perceive differences between guitars, but the resulting clusters do not show an ebony/rosewood dichotomy. A linguistic analysis of the verbalisations exhibits psychological descriptors that are relevant for the discrimination of the wood of the fingerboard: PRECISION (referring to how each note stands out from others), and to a lesser extent ATTACK (referring to the guitar's response to musician's gesture) and BALANCE (referring to the frequency content). This study is part of a broader project aiming at establishing an explicite relation between mechanics, perception, and lutherie. A physical interpretation of the psychologically-relevant descriptors is eventually proposed in order to use them as hypotheses in a further hypothetico-deductive approach starting from physics and using psychophysical methods.

In this paper, we considered the study of Friedmann–Robertson–Walker (FRW) model in the framework of [Formula: see text] gravity, an extension of symmetric teleparallel gravity, recently defined by Xu et al. [[Formula: see text] gravity, Eur. Phys. J. C 79 (2019) 708]. The nonlinear model [Formula: see text], where [Formula: see text] and [Formula: see text] are constants, is taken into account. The equation of state of perfect fluid is assumed and 31 points of Hubble data are used to constrain the value of model parameter. To explore the evolution of the universe, the numerical solutions of cosmological implications, such as Hubble parameter, deceleration parameter, apparent magnitude and luminosity distance, are determined and the energy conditions are examined. The theoretical results of Hubble parameter are compared with [Formula: see text]CDM model. Further, 57 Supernova data (42 from Supernova cosmology project and 15 from Calán/Tolono supernova survey) are also used to have c...

STRAIGHT, a speech analysis, modification synthesis system, is an extension of the classical channel VOCODER that exploits the advantages of progress in information processing technologies and a new conceptualization of the role of repetitive structures in speech sounds. This review outlines historical backgrounds, architecture, underlying principles, and representative applications of STRAIGHT.

The nature of oscillations in the 1 kHz-60 MHz frequency range that have been observed during operation of Hall thrusters is quantitatively discussed. Contours of various plasma parameters measured inside the accelerating channel of a typical Hall thruster are used to evaluate the various stability criteria and dispersion relations of oscillations that are suspected to occur. A band by band up-to-date overview of the oscillations is carried out with a description of their observed behavior and a discussion of their nature and dependencies through comparison of the calculated contours to reported observations. The discussion encompasses the excitation of low frequency azimuthal drift waves that can form a rotating spoke, axially propagating ''transit-time'' oscillations, azimuthal drift waves, ionization instability-type waves, and wave emission peculiar to weakly ionized inhomogeneous plasmas in crossed electric and magnetic fields.

Considering the dynamic nature of portable computing devices with wireless communication capability, an extended model is introduced for worm spreading in the wireless ad hoc network, with a population of mobile agents in a planar distribution, starting from an initial infected seed. The effect of agents' mobility on worm spreading is investigated via extensive Monte Carlo simulations. The threshold behavior and the dynamics of worm epidemics in the wireless networks are greatly affected by both agents' mobility and spatial and temporal correlations. The medium access control mechanism for the wireless communication promotes the sensitivity of the spreading dynamics to agents' mobility.

In the textbook proofs of Lorentz covariance of the Dirac equation, one treats the wave function as a spinor and gamma matrices as scalars, leading to a quite complicated formalism with several pedagogic drawbacks. As an alternative, I propose to teach Dirac equation and its Lorentz covariance by using a much simpler, but physically equivalent formalism, in which these drawbacks do not appear. In this alternative formalism, the wave function transforms as a scalar and gamma matrices as components of a vector, such that the standard physically relevant bilinear combinations do not change their transformation properties. The alternative formalism allows also a natural construction of some additional non-standard bilinear combinations with well-defined transformation properties.

Two ITER TF dual channel Cable-in-Conduit Conductors (CICCs) have been tested in the SULTAN test facility. The samples were heated either by foil heaters mounted on the outside of the conductor jacket or by induced AC losses. The steady-state temperature response of several thermometers installed on the jacket surface as well as inside the cable were analyzed using the two-channel analytical model proposed by Renard et al. to obtain the equivalent transverse heat transfer coefficient between the bundle and central channel as a function of the mass flow rate. In addition, on the basis of the measured pressure drop and helium flow velocities, the friction factors for helium flow in the bundle and in the central channel were determined. The obtained results may serve as a reference for these cables.

Data have been compiled from the published literature on the partition coefficients of solutes and vapors into chloroform, carbon tetrachloride, dichloromethane and 1-chlorobutane from both water and from the gas phase. The logarithms of the water-to-chloroalkane (log P) and gas-tochloroalkane partition coefficients (log K) are correlated with the Abraham solvation parameter model. The derived correlations describe the observed log P and log K values within standard deviations of about 0.13 to 0.20 log units. For chloroform and carbon tetrachloride, the derived correlations were validated using training set and test set analyses. 2

The linear gradient theory (LGT) combined with the Soave-Redlich-Kwong (SRK EoS) and the Peng-Robinson (PR EoS) equations of state has been used to correlate the interfacial tension data of the methane-water system. The pure component influence parameters and the binary interaction coefficient for the mixture influence parameter have been obtained for this system. The model was successfully applied to correlate the interfacial tension data set to within 2.3% for the linear gradient theory and the SRK EoS (LGT-SRK) and 2.5% for the linear gradient theory and PE EoS (LGT-PR). A posteriori comparison of data not used in the parameterisation were to within 3.2% for the LGT-SRK model and 2.7% for the LGT-PR model. An exhaustive literature review resulted in a large database for the investigation which covers a wide range of temperature and pressures. The results support the success of the linear gradient theory modelling approach for this system.

High-order finite-difference schemes are less dispersive and dissipative but, at the same time, more isotropic than low-order schemes. They are well suited for solving computational acoustics problems. High-order finite-difference equations, however, support extraneous wave solutions which bear no resemblance to the exact solution of the original partial differential equations. These extraneous wave solutions, which invariably degrade the quality of the numerical solutions, are usually generated when solid-wall boundary conditions are imposed. A set of numerical boundary conditions simulating the presence of a solid wall for high-order finitedifference schemes using a minimum number of ghost values is proposed. The effectiveness of the numerical boundary conditions in producing quality solutions is analyzed and demonstrated by comparing the results of direct numerical simulations and exact solutions.

Photoacoustic spectroscopy (PAS) is widely used for diverse applications in different areas. These include studies in material, environmental, and life sciences. In the present work the study of pigments from pottery surfaces and volumes of Mexican (Aztec) and Poblana cultures that were developed in central Mexico from 1325 to 1521 and 1521 to 1800, respectively, is reported. The optical absorption spectra from each archeological sample was obtained using PAS. The superficial spectra were also compared with standard color pigments and archeological registers. Complementary energy dispersive spectroscopy (EDS) analysis of these archeological potteries gave us their elemental composition which agreed with other studies about their composition and technology of the pottery manufacturing.

Quantum Zakharov equations are obtained to describe the nonlinear interaction between quantum Langmuir waves and quantum ion-acoustic waves. These quantum Zakharov equations are applied to two model cases, namely the four-wave interaction and the decay instability. In the case of the four-wave instability, sufficiently large quantum effects tend to suppress the instability.