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This article discusses the use of spectrograms to analyze bird vocalizations and simulate bird songs using a sliding whistle and a smartphone. Spectrograms provide information about the frequency, duration, pitch, and modulation of bird sounds. The article also presents examples of different bird vocalizations, such as trills and clicking sounds, and explains how they can be replicated using the sliding whistle. The use of spectrograms and smartphone applications allows students to explore the physics of bird songs and engage in interactive learning activities. The author, Regis Barille, has a background in electronics and optronics and has conducted extensive research in experimental physics and environmental metrology. [Extracted from the article]

This article explores the use of smartphones as a tool to measure cabin pressure during flights. The study focuses on the pressure variations during takeoff and climbing, aiming to understand the relationship between pressure, altitude, and cabin pressurization for passenger comfort and safety. The article also discusses the management of cabin pressure throughout different stages of a flight, highlighting the role of the pressurization system in maintaining a safe level of oxygen for passengers. Additionally, the article suggests that studying cabin pressure variations can provide insights into pressure management in other systems, such as submarines or scuba diving. [Extracted from the article]

Magnesium-doped zinc oxide thin films were dip-coated onto porous ceramic and glass substrates under identical conditions (50 layers, same doping ratio). Structural, morphological, and photocatalytic properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), UV–visible spectrophotometry, and confocal microscopy. XRD analysis indicated a shift in peak positions towards higher angles, increased grain size, and lattice distortion on both substrates. Unique flower-shaped crystalline granulates were observed exclusively on the ceramic substrate (DD3Z). The energy gap decreased on the ceramic and increased on the glass substrate. The photocatalytic activity was evaluated using an aqueous orange II solution, showing significantly higher decomposition (80 ± 0.53 % after 6 h) on the ceramic compared to the glass substrate (30 %). The enhanced performance on ceramic substrates, particularly with DD3+ZrO 2 , was attributed to increased microporosity, surface roughness, and active material incorporation, facilitating greater photocatalytic efficiency. The findings suggest promising applications of these materials for efficient and cost-effective photocatalysis, with potential for reuse after thermal treatment at 500 °C. [ABSTRACT FROM AUTHOR]

To evaluate the role played by the substrates on the change and the actual difference of the studied samples on their structural, morphological, optical and photocatalytic properties, thin layers of zinc oxide grafted with magnesium were prepared with the same number of layers, doping ratio and experimental conditions with the use of two types of porous ceramic substrates and glassy. The XRD analysis detected the polycrystalline structure with wurtzite-type for all synthesized samples. The grain size was found to vary between 39 and 21 nm for DD3Z and 23 nm to 17 for glass. UV–visible absorbance data indicated that all MZO films absorb visible light at around 410 nm. In addition, a blue shift toward shorter wavelengths side was noted with increasing magnesium content up to 4 wt%, while the band gap showed an increasing trend achieving 3.07 eV for ceramics substrate. SEM analysis showed that the doping greatly affected the morphology of ZnO samples. Based on the results shown by the photocatalytic activities of orange II, the doping with magnesium gave a significant improvement to the samples with a ceramic substrate compared to the samples with a glass substrate. To reveal the mechanism of photolysis Hole/radical scavengers were used. It was found that the addition of Mg–ZnO networks increases the adsorption of hydroxyl ions on the surface and thus acts as a trap site leading to the reduction of hole/electron pair and thus increasing the activity and enhancing photodegradation. [ABSTRACT FROM AUTHOR]

In this work, a novel photoresponsive materials has been successfully developed. We have synthesized the series of azopolymers containing derivatives of sulfamerazine and studied their photochromic properties. The polymers were obtained from methacrylate azomonomers, butyl methacrylate and isobornyl methacrylate by radical polymerization. Spectral properties and photoisomerization kinetic constants were determined for thin transparent films, using UV–Vis spectroscopy. The maximum absorption of the films was observed at 432–440 nm. The obtained materials showed ability to reversible trans – cis photoisomerization. Reversibility of the process was confirmed during ellipsometric measurements. The change of the real part of the complex refractive index induced by laser irradiation was between 0.010 and 0.053. Additionally, some properties of described polymers and azobenzene derivatives were calculated and were utilized in order to better understand the differences in the photochromic behaviour of the new materials. Moreover, we determined the suitability of the obtained azopolymers for spontaneous surface relief grating inscription. Spontaneous surface relief grating recording on the thin azopolymer films was carried out using set-up with one laser beam. The spontaneous SRG was successfully recorded in all investigated polymers. [ABSTRACT FROM AUTHOR]

The hunt for active components creates new opportunities to modify photocatalysis materials that we use on a daily basis to cleanse water from pollutants that pose a threat to human life and living organisms. The current study focuses on studying the structural, morphological, optical, electrical, and photocatalytic features of copper oxide (CuO). The work employs the sol-gel spin coating technique to investigate the structural, morphological, optical, electrical, and photocatalytic properties of copper oxide (CuO) doped with different concentrations (x = 5, 15, 25, and 50 wt %) of zinc (Zn). X-ray diffraction (XRD), atomic force microscope (AFM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and Fourier-transform infrared spectroscopy (FT-IR), UV–visible spectrophotometry (UV–Visible), and the four-point method were among the analytical techniques used to characterize the Cu 1-x Zn x O thin films. The films exhibit variation in thickness, ranging from 340 nm to 96 nm, as doping intensifies. Every film has a polycrystalline structure with crystallite sizes ranging from 27 to 51 nm, according to the results of the X-ray diffraction (XRD) investigation. The energy gap drops with increased doping, from 2.74 eV to 1.81 eV. The enhanced capacitance is elucidated by the presence of Zn particles within CuO nanostructures, which results in a notable enhancement of electrical conductivity. The introduction of Zn impurity into copper oxide resulted in a substantial enhancement in its photocatalysis activity when thin films of CuO doped with 50 wt% Zn were used, and the best degradation of orange II dye reached 30 %. It is considered that Zn-doped CuO can be an effective material for screening dyes using light, improving water quality, and addressing environmental difficulties. • Zn-doped CuO thin films have been prepared by the Spin-coating method. • XRD and MEB analysis showed that the crystallite sizeincreased with Zn doping rate andhad a nano-spherical shape and pores that enhanced photocatalysis degradation. • The deposited Zn:CuO thin layers showed a smooth, dense, and homogeneous surface. • Efficient decomposition, while applying photocatalysis ofOrange II. [ABSTRACT FROM AUTHOR]

Abstract: The copolymers consisting of chiral (S)-(−)-1-(4-nitrophenyl)pyrrolidin-2-yl]methyl 2-methacrylate ((S)-PYM) and azobenzene methacrylic co-monomers: 2-(methyl{4-[(E)-(5-methylisoxazol-3-yl)diazenyl]phenyl}amino)ethyl 2-methacrylate (ISM) or 2-{[4-[4-{(2,6-dimethylpirymidin-4-yl)amino]sulfonyl}phenyl) diazenyl]phenyl}-(methyl)amino]ethyl 2-methacrylate (SUM) were synthesized by radical polymerization. The quantum chemical calculations were carried out to predict spectral and nonlinear optical properties of the materials in question. The copolymers showed reversible photochromic properties under illumination with light by change of UV–vis spectra and ellipsometric parameters. The ellipsometric measurements made it possible to determine the change of refractive index under illumination that was in the range between 0.017 and 0.041 depending on copolymer type. Photochromic gratings were inscribed on the surface of polymer films in two kinds of experiments, leading to interesting conclusion that the surface relief grating could be recorded by two interfering laser beams as well as by a single linearly polarized laser beam. The chirooptical properties of the materials were investigated by circular dichroism spectroscopy. [Copyright &y& Elsevier]

We compare in this study two simple optical setups to measure the atmospheric turbulence characterized by the refractive index structure parameter C n 2 . The corresponding heat flux values sensed by the laser beam propagation are calculated leading to the plant evapotranspiration. The results are discussed and compared to measurements obtained with a well-known and calibrated eddy-covariant instrument. A fine analysis gives a good insight of the accuracy of the optical devices proposed here to measure the crop evapotranspiration. Additional evapotranspiration values calculated with meteorological sensor data and the use of different models are also compared in parallel. [ABSTRACT FROM AUTHOR]

The new photochromic hybrid materials containing different mole fractions of highly photoactive 4-[(E)-[4-[ethyl(2-hydroxyethyl)amino]phenyl]azo]-N-(4-methylpyrimidin-2-yl)benzenesulfonamide (SMERe) were prepared by a low temperature sol–gel process. The guest–host systems with triethoxyphenylsilane matrix were obtained. These materials were used to form thin transparent films by a spin-coating technique. Then the ability of thin hybrid films to reversible trans–cis photoisomerization under illumination was investigated using ellipsometry and UV–Vis spectroscopy. The reversible changes of refractive index of the films under illumination were in the range of 0.005–0.056. The maximum absorption of these materials was located at 462–486 nm. Moreover, the organic–inorganic azobenzene materials were used to form nanofibers by electrospinning using various parameters of the process. The microstructure of electrospun fibers depended on sols properties (e.g. concentration and viscosity of the sols) and process conditions (e.g. the applied voltage, temperature or type of the collector) at ambient conditions. The morphology of obtained nanofibers was analyzed by an optical microscopy and scanning electron microscopy. In most instances, the beadless fibers were obtained. The wettability of the surface of electrospun fibers deposited on glass substrates was investigated. [ABSTRACT FROM AUTHOR]

Properties such as absorption, structural and external aspect of Carbopol/silver nanoparticles composites, prepared in DMF by heating process up to 30, 60, 80, 100 and 120 °C, were investigated by UV-visible, FTIR and SEM-EDS analyses. Samples were named respectively D30 to D120, according to the temperature at which they were extracted. The results showed that instead of the appearance of silver aggregates observed by SEM microscopy, all the obtained materials present a single absorption band centred at 430 nm, attributed to the classical surface plasmon excitation of the silver nanoparticles. The presence of silver nanoparticles is also proved by the X-ray powder diffraction XRD patterns, which show the appearance of small peaks corresponding to the face centered cubic (f.c.c.) silver phase in the case of D100 and D120 samples. Additionally strong interactions between silver ions and carboxylic groups of Carbopol were identified by ATR-FTIR spectroscopy. The thermal properties of the carbopol are effectively enhanced by the presence of silver nanoparticles as evidenced by thermo-gravimetric analysis. Furthermore the water loss that generally occurs at 100 °C in acrylic acid polymer was completely avoided in these new materials since less than 2 % of weight loss is recorded up to 160 °C. Finally, the inhibiting activity of Carbopol/silver nanoparticles composites against staphylococcus Aureus micro-organisms was confirmed for all the obtained materials, suggesting their suitable uses as effective growth inhibitors of micro-organisms and making them appropriate for diverse antimicrobial control systems. [ABSTRACT FROM AUTHOR]

The photochromic polymer and sol-gel hybrid materials containing azo isoxazole derivatives were prepared. These new materials were used to form transparent films on glass plates by spin-coating technique. The maximum absorption band of the film was observed at 412-414 nm and 422 nm for polymer and hybrid materials, respectively. Illumination of the films with light caused isomerization of the diazo group manifested by decrease of the absorbance. The isomerization monitored during ellipsometric measurements showed decrease of refractive index on illumination. The magnitude of modulation of real part of the refractive index was in the range between 0.017 and 0.026. The surface relief grating (SRG) was successfully recorded in both polymer and copolymers films, containing methylisoxazole dye in the side chain. The refractive index modulation was also observed in the hybrid sol-gel film however no surface relief grating was recorded after 30 min inscription time. [ABSTRACT FROM AUTHOR]

Abstract: The methacrylate terpolymers, a nonchromophoric and chromophoric one, containing 2-hydroxyethyl groups were reacted with 3-isocyanatopropyltriethoxysilane to obtain reactive polymers able to form covalent bonding with –SiOH groups of the glass surface via triethoxysilane group condensation. Chemical modification of the Corning 2949 glass plates treated in this way resulted in increase of wetting angle from 11° to ca. 70–73°. Determination of ellipsometric parameters revealed low value of the substrate refractive index as compared with that of bulk Corning 2949 glass suggesting roughness of the surface. The AFM image of the bare glass surface and that modified with terpolymer monolayer confirmed this phenomenon. Modification of the glass with the terpolymer monolayer made it possible to create the substrate surface well suited for deposition of familiar chromophore film by spin-coating. The chromophore polymer film deposited onto the modified glass surface was found to be resistant to come unstuck in aqueous solution. [Copyright &y& Elsevier]

CuIn1-xZnxSe2 powders with various atomic percentages (x = 0, 0.05, 0.11, 0.16 and 0.21) were synthesized with the solvothermal method using metal chlorides and ethylendiamine as sources of precursors and a solvent, respectively. The experiment aims to investigate the effect of atomic percentages of Znx compounds on the structural and optical properties of CuIn1-xZnxSe2 in order to improve future technological applications based on this material. The powders' chalcopyrite phases were identified by X-ray diffraction. Energy dispersive X-ray spectroscopy analysis revealed the presence of Cu, In, Zn and Se with the expected atomic ratio of Zn/(In + Zn). Scanning electron microscopy and transmission electron microscopy analysis showed that the powders have large-scale desert rose-like structures. The nanopowders' optical study by UV-visible spectrophotometry showed that the CuIn1-xZnxSe2 energy gap values increase with the molar fraction of Znx. A change from 1.15 to 1.4 eV was observed. [ABSTRACT FROM AUTHOR]

Abstract: The chromophoric intermediate: 2,2′-({4-[(E)-(5-methylisoxazol-3-yl)diazenyl]phenyl}-imino)diethanol was used in polyaddition reaction with di-isocyanate to obtain a new polyurethane polymeric material showing nonlinear optical and photochromic properties. The maximum absorption band of the polymer film was at 418nm. The illumination of the film with crossed beams of the 488nm Ar+ laser yielded surface relief grating of regular structure. Measurement of the frequency doubling signal with 1064nm laser indicated the polymer as interesting material for photooptical applications. The measured nonlinear optical coefficient, d 33, reached 90.2pm/V. [Copyright &y& Elsevier]

• Cr-V-C-N coatings were deposited using magnetron sputtering technique. • The carbide and nitride phases were detected in the Cr-V-C-N coatings. • All Cr-V-C-N coatings exhibited dense and columnar morphology. • Carbon promoted the grain refinement of the nanocrystalline Cr-V-C-N coatings. • Cr 0.22 V 0.21 C 0.28 N 0.24 coating presented the best tribo-mechanical behavior. Cr-V-C-N thin films were deposited on XC100 steel and Si(100) wafers by a radio frequency magnetron sputtering technique using chromium and vanadium targets in an Ar/N 2 /CH 4 mixture atmosphere. The microstructure, mechanical and tribological properties of coatings were investigated as a function of carbon content. It has been found that the quaternary Cr-V-C-N coatings containing a low percentage of carbon (≤ 12.4 at.%) exhibited a mixture of chromium and vanadium nitrides nano-sized crystallite phases. The coatings containing a high carbon content (> 25 at.%) were consisted of nitride and carbide phases, where the large carbon atoms inserted through CrN and VN. Mechanical properties of the Cr-V-C-N coatings were influenced by the carbon addition. The maximum hardness value of 28.3 GPa was obtained for the coating containing 28 at.% of carbon which is related to the adhesion strength enhanced by the formation of carbide and nitride mixture. Addition of carbon into the Cr-V-N coating led to significantly decrease its friction coefficient from 0.63 to 0.47. The formation of carbides through the dispersion of carbon in the grains effectively improved the density of the Cr-V-C-N coatings so that the coating deposited under a high CH 4 flow rate exhibited a better wear resistance than the other Cr-V-N and Cr-V-C coatings. [ABSTRACT FROM AUTHOR]