Characterisation and differentiation of pigments employed on the façade of “Noto’s Valley” monuments (Sicily)

Most of the “Noto’s Valley” monuments façades, located in different towns of Sicily such as Ragusa Ibla, Modica and Noto, present different colours and in many cases the towns themselves are characterized by evident chromatic variations. The knowledge of colour and in particular the characterization of pigments is of utmost importance in the baroque Sicilian buildings, because the peculiarity of the colour is one of the features that makes the “Noto Valley” monuments a World Cultural Heritage site. The present works aim is to characterise and differentiate the pigments used on the façade of monuments and inside the plasters. In particular, we perform a micro-textural and analytical analysis through scanning electron microscopy (SEM) and a mineralogical investigation through the conjunction of optical microscopy and fourier transform infrared spectroscopy (FT-IR). All the experimental results have allowed us to clearly classify the pigments into earths rich in clay minerals and earth containing gypsum. Furthermore, we also show that the earths rich in clay minerals from Ragusa and Modica areas have local provenance.     

Procedure for verification of sound source coverage over façades according to the International Standard ISO 140–5

This paper presents a new verification procedure for sound source coverage according to ISO 140–5 requirements. The ISO 140–5 standard applies to the measurement of façade insulation and requires a sound source able to achieve a sufficiently uniform sound field in free field conditions on the façade under study. The proposed method involves the electroacoustic characterisation of the sound source in laboratory free field conditions (anechoic room) and the subsequent prediction by computer simulation of the sound free field radiated on a rectangular surface equal in size to the façade being measured. The loudspeaker is characterised in an anechoic room under laboratory controlled conditions, carefully measuring directivity, and then a computer model is designed to calculate the acoustic free field coverage for different loudspeaker positions and façade sizes. For each sound source position, the method provides the maximum direct acoustic level differences on a façade specimen and therefore determines whether the loudspeaker verifies the maximum allowed level difference of 5 dB (or 10 dB for façade dimensions greater than 5 m) required by the ISO standard. Additionally, the maximum horizontal dimension of the façade meeting the standard is calculated and provided for each sound source position, both with the 5 dB and 10 dB criteria. In the last section of the paper, the proposed procedure is compared with another method used by the authors in the past to achieve the same purpose: in situ outdoor measurements attempting to recreate free field conditions. From this comparison, it is concluded that the proposed method is able to reproduce the actual measurements with high accuracy, for example, the ground reflection effect, at least at low frequencies, which is difficult to avoid in the outdoor measurement method, and it is fully eliminated with the proposed method to achieve the free field requisite.     

Joint reconstruction of the speed of sound,absorption, and flows by the Novikov–Agaltsov functional algorithm

Numerical implementation of the two-dimensional functional-analytical Novikov–Agaltsov algorithm is considered and its possibilities are discussed. This algorithm is intended for reconstructing combined scalar-vector inhomogeneities describing spatial distributions of the speed of sound, absorption, and vector flow field. The results of the numerical simulation of the algorithm in the single- and multifrequency probing modes are presented. The obtained results illustrate an acceptable accuracy and interference resistance of the obtained estimates, which illustrates the application prospects of the algorithm in practical problems of acoustic tomography.     

Influence of loudspeaker directivity and measurement geometry on direct acoustic levels over façades for acoustic insulation tests with the International Standard ISO 140-5

The International Standard ISO 140-5 on field measurements of airborne sound insulation of façades establishes that the directivity of the measurement loudspeaker should be such that the variation in the local direct sound pressure level (ΔSPL) on the sample is ΔSPL < 5 dB (or ΔSPL < 10 dB for large façades). This condition is usually not very easy to accomplish nor is it easy to verify whether the loudspeaker produces such a uniform level. Direct sound pressure levels on the ISO standard façade essentially depend on the distance and directivity of the loudspeaker used. This paper presents a comprehensive analysis of the test geometry for measuring sound insulation and explains how the loudspeaker directivity, combined with distance, affects the acoustic level distribution on the façade.The first sections of the paper are focused on analysing the measurement geometry and its influence on the direct acoustic level variations on the façade. The most favourable and least favourable positions to minimise these direct acoustic level differences are found, and the angles covered by the façade in the reference system of the loudspeaker are also determined. Then, the maximum dimensions of the façade that meet the conditions of the ISO 140-5 standard are obtained for the ideal omnidirectional sound source and the piston radiating in an infinite baffle, which is chosen as the typical radiation pattern for loudspeakers.Finally, a complete study of the behaviour of different loudspeaker radiation models (such as those usually utilised in the ISO 140-5 measurements) is performed, comparing their radiation maps on the façade for searching their maximum dimensions and the most appropriate radiation configurations.     

The Fourier slice theorem for ultrasonic reflectivity tomography and the correction to the effect caused by curvature of integral lines

For ultrasonic reflective tomographic imaging of differenttransmitter-receiver mode,we demonstrate that the Fourier slice theorem canbe used when the distance between the transducer and origin becomes muchlarger than the object to be reconstructed.Iterative reconstruction formulabased on the Fourier slice theorem is proposed for the case in which theparaxial approximation holds.The effect caused by the curvature of integrallines may be eliminated iteratively and better reconstructed images can be ex-pected.     

Threshold curves obtained under various gaseous conditions for free radical generation by burst ultrasound – Effects of dissolved gas,microbubbles and gas transport from the air

To understand the underlying concepts required for the determination of thresholds for free radical generation, effects of gas dissolution in and microbubble addition to sonicated solutions were investigated. Four solutions with different gaseous conditions, air-saturated and degassed solutions with and without microbubbles of 20 μm in diameter with shells, were studied in the presence of an air–liquid interface. These test solutions were exposed to 1 MHz ultrasound of 0.06 MPa_p-p at various pulse durations (PDs) from 0.1 to 5 ms and pulse repetition frequencies from 0.1 to 2 kHz. Generation of free radicals was evaluated using the electron spin resonance (ESR) spin trapping method and starch–iodine method. Thresholds of duty ratio (DR) corresponding to temporal average intensity of ultrasound for free radical generation were significantly greater in degassed solutions than in air-saturated solutions. Microbubbles had no significant effects in air-saturated solutions but caused a slight decrease in the threshold in degassed solutions. In all of these results, the DR of a threshold curve against pulse repetition period (PRP) was not constant but linearly decreased with it, suggesting that a balance between bubble growth and shrinkage during the ON and OFF times of burst ultrasound is the primary parameter for the interpretation of thresholds. The effect of an air–liquid interface of the solution was also examined, and it was revealed that gas transport from the air is a predominant factor determining the amount of free radicals.     

Rotational components of the v8 = 1, 2, and 3 and ground vibrational levels of CH3C15N for the frequency range 17–75 GHz

The microwave spectrum of methyl cyanide CH₃C¹⁵N was studied for the v₈ = 3 vibrational state in the frequency range of 17 to 75 GHz. In addition, some rotational components for the ground, v₈ = 1 and 2 were remeasured and these results compared to those found in the literature. The frequencies of 42 components were measured and these frequencies were used to produce a constant set which can be used to predict overall frequencies of spectral components in the ground, v₈ = 1, 2 up to an accuracy of 100 KHz and those for v₈ = 3, 4 up to an accuracy of 150 KHz. Previously obtained experimental data, available from the literature, and our own data for the ground, v₈ = 1 and 2, and the new data for v₈ = 3 are presented and compared with the frequencies obtained from a comprehensive equation derived from perturbation techniques.     

The first Brillouin zone of the hexagonal close-packed structure and study on the properties of vacancies and phonon dispersions by the improved ones of the modified analytic embedded atom method potentials for Ru,Sc, Ti,Y, and Zr

ABSTRACT

We studied the first Brillouin zone of the hexagonal close-packed (HCP) structure and the improved ones of the modified analytical embedded atom method (EAM) potentials were adopted to calculate the properties of the mono- and bi-vacancies and the phonon dispersions for HCP transition metals Ru, Sc, Ti, Y, and Zr. The agreements with the experimental data showed that the improved potentials for the HCP transition metals are available.     

Silica Nanoparticles as Adhesives for Biological Tissues? Re‐Examining the Effect of Particles Size,Particle Shape,and the Unexpected Role of Base

Development of new, effective, and patient‐friendly adhesives for biological tissues is important for medical and surgical practices such as bleeding control and organ repairing. While some commercially available silica nanoparticles such as LUDOX SM‐30 have shown adhesive properties for biological tissues, the role of inorganic base present in the adhesive properties of the silica nanoparticles has not been examined. Moreover, it remained unclear how the size and the shape of silica nanoparticles affect the adhesion properties. To address these questions, synthesis and characterization of a series of uniform silica nanostructures with different sizes and shapes is carried out. Unexpectedly, none of the synthesized silica nanostructures without additional inorganic base shows adhesion properties against liver tissues. Such surprising phenomena motivate to examine other factors in the commercial silica nanoparticles as tissue adhesives, and reach a conclusion that the inorganic base plays a key role in the adhesion properties. It is believed that this study answers the important question whether silica nanoparticles can act as biological adhesives or not. The conclusion also gives a lesson to other scientists and engineers in design and exploration of new biological adhesives.     

Investigation of analytical harmonic frequency and potential energy function,vibrational levels for the X^2∑^＋ and A^2Л states of CN radical

This paper calculates the equilibrium structure and the potential energy functions of the ground state （X^2∑^＋） and the low lying excited electronic state （A^2Л） of CN radical are calculated by using CASSCF method. The potential energy curves are obtained by a least square fitting to the modified Murrell-Sorbie function. On the basis of physical theory of potential energy function, harmonic frequency （ωe） and other spectroscopic constants （ωeχe, βe and αe） are calculated by employing the Rydberg-Klei-Rees method. The theoretical calculation results are in excellent agreement with the experimental and other complicated theoretical calculation data. In addition, the eigenvalues of vibrational levels have been calculated by solving the radial one-dimensional SchrSdinger equation of nuclear motion using the algebraic method based on the analytical potential energy function.     

Line broadening,shifting and mixing parameters for the ν1 + ν3 band of OCS perturbed by N2 and O2

In this paper, we report measured Rosenkranz N₂- and O₂-broadening, induced pressure-shift and mixing coefficients for OCS in the ν₁ + ν₃ band, using a multi-pressure fitting technique applied to the measured shapes of the lines, including the interference effects caused by the line overlaps. These measurements were made by analysing six laboratory absorption spectra recorded at 0.004 cm^?1 resolution using the Fourier transform spectrometer Bruker IFS125HR located at the Laboratoire Interuniversitaire des Systèmes Atmosphériques, in Créteil. The spectra have been recorded in the 1850–3000 cm^?1 wave number range at 295 K, using a multipass absorption cell with an optical path of 3.249 m. The total sample pressures ranged from 5.97 to 83.28 Torr with OCS volume mixing ratios between 0.001 and 0.013 in nitrogen or oxygen. We have been able to determine the N₂- and O₂-pressure-broadening coefficients of 81 ν₁ + ν₃ transitions with rotational quantum number J up to 50. The measured N₂- and O₂-broadening coefficients range from 0.0815 ± 0.0698 to 0.1169 ± 0.1027 cm^?1 atm^?1 at 295 K, respectively. Most of the measured pressure shifts are positive. The reported N₂- and O₂-induced pressure-shift coefficients vary from about ?0.0103 ± 0.0092 to 0.0097 ± 0.0092 cm^?1 atm^?1, respectively. We have examined the dependence of the measured broadening parameters on the quantum number m (m = ?J for the P branch and m = J + 1 for the R branch) and also developed an empirical expression to describe the broadening coefficients in terms of |m|. On average, this empirical expression reproduces the measured broadening coefficients to within 2%. Using a semi-classical Robert and Bonamy formalism, the theoretical broadening coefficients have been calculated at room temperature and compared with the experimental results. The theoretical results of the broadening coefficients are in very good overall agreement with the experimental data (2%).     

Calculating Hamiltonian parameters for Yb^3＋ in a low-symmetry lattice site, and fitting the structure and levels of Yb^3＋ ：RETaO4 （RE = Gd, Y, and Sc）

An iterative method is used to find the values of the Hamiltonian parameters for Yb^3＋ in a given low-symmetry crys- talline site. Samples of Yb^3＋ ：RETaO4 （RE = Gd, Y, and Sc） were prepared and their structures were determined. Based on the obtained structural data, their orbital-spin parameters and crystal field parameters were fitted by the superposition model （SM）. Using the crystal field parameters obtained by the SM fitting as the initial parameters, the Hamiltonian parameters were fitted iteratively. The calculated and experimental energy levels for Yb^3＋：RETaO4 are consistent, and the maximal mean-root-square deviation is only 2.84 cm^- 1, indicating that the method is effective to determine the Hamiltonian parameters of Yb^3＋ in low-symmetry crystalline sites.     

Lead and strontium isotopes as indicators for mixing processes of waters in the former mine ‘Himmelfahrt Fundgrube’, Freiberg (Germany)†

To pinpoint the origin and mixing processes of mine waters, different mine water types from the polymetallic sulphide ore deposit ‘Himmelfahrt Fundgrube’ (Freiberg, Germany) were analysed by thermal ionisation mass spectrometry using lead and strontium isotope ratios.

Results show that the lead isotope composition of different mine waters results from a mixture of at least two sources: released lead from oxidised sulphide ores (mainly galena) and anthropogenic lead from groundwater. Furthermore, there are indications for an additional lead source. Strontium isotopes in mine waters identify at least three different sources: released strontium from weathered host rock (Grey Gneisses), released strontium from weathered gangue carbonates, and probably strontium from anthropogenic inputs. Contrary to former oxygen and sulphur isotope studies, strontium isotope compositions as well as hydrochemical parameters show the important role of gangue carbonates as an element source in mine waters.     

A green method for the synthesis of pyrrole derivatives using arylglyoxals, 1,3-diketones and enaminoketones in water or water–ethanol mixture as solvent

Molecular Diversity - Three-component reaction between arylglyoxals, 1,3-dicetones and enaminoketones leads to new polyfunctionalized tetraone derivatives which may be easily converted to...